diff options
Diffstat (limited to 'contrib/gcc')
| -rw-r--r-- | contrib/gcc/cp/g++.1 | 1 | ||||
| -rw-r--r-- | contrib/gcc/cpp.1 | 1 | ||||
| -rw-r--r-- | contrib/gcc/doc/cpp.1 | 817 | ||||
| -rw-r--r-- | contrib/gcc/doc/gcc.1 | 9464 | ||||
| -rw-r--r-- | contrib/gcc/doc/gcov.1 | 453 | ||||
| -rw-r--r-- | contrib/gcc/f/BUGS | 130 | ||||
| -rw-r--r-- | contrib/gcc/f/NEWS | 531 | ||||
| -rw-r--r-- | contrib/gcc/f/g77.1 | 1719 | ||||
| -rw-r--r-- | contrib/gcc/gcc.1 | 4191 |
9 files changed, 0 insertions, 17307 deletions
diff --git a/contrib/gcc/cp/g++.1 b/contrib/gcc/cp/g++.1 deleted file mode 100644 index a5be7bceeff4..000000000000 --- a/contrib/gcc/cp/g++.1 +++ /dev/null @@ -1 +0,0 @@ -.so man1/gcc.1 diff --git a/contrib/gcc/cpp.1 b/contrib/gcc/cpp.1 deleted file mode 100644 index 54c4dfb19832..000000000000 --- a/contrib/gcc/cpp.1 +++ /dev/null @@ -1 +0,0 @@ -.so man1/cccp.1 diff --git a/contrib/gcc/doc/cpp.1 b/contrib/gcc/doc/cpp.1 deleted file mode 100644 index 8b7412325911..000000000000 --- a/contrib/gcc/doc/cpp.1 +++ /dev/null @@ -1,817 +0,0 @@ -.\" Automatically generated by Pod::Man version 1.15 -.\" Wed Feb 5 03:13:55 2003 -.\" -.\" Standard preamble: -.\" ====================================================================== -.de Sh \" Subsection heading -.br -.if t .Sp -.ne 5 -.PP -\fB\\$1\fR -.PP -.. -.de Sp \" Vertical space (when we can't use .PP) -.if t .sp .5v -.if n .sp -.. -.de Ip \" List item -.br -.ie \\n(.$>=3 .ne \\$3 -.el .ne 3 -.IP "\\$1" \\$2 -.. -.de Vb \" Begin verbatim text -.ft CW -.nf -.ne \\$1 -.. -.de Ve \" End verbatim text -.ft R - -.fi -.. -.\" Set up some character translations and predefined strings. \*(-- will -.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left -.\" double quote, and \*(R" will give a right double quote. | will give a -.\" real vertical bar. \*(C+ will give a nicer C++. Capital omega is used -.\" to do unbreakable dashes and therefore won't be available. \*(C` and -.\" \*(C' expand to `' in nroff, nothing in troff, for use with C<> -.tr \(*W-|\(bv\*(Tr -.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' -.ie n \{\ -. ds -- \(*W- -. ds PI pi -. if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch -. if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch -. ds L" "" -. ds R" "" -. ds C` "" -. ds C' "" -'br\} -.el\{\ -. ds -- \|\(em\| -. ds PI \(*p -. ds L" `` -. ds R" '' -'br\} -.\" -.\" If the F register is turned on, we'll generate index entries on stderr -.\" for titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and -.\" index entries marked with X<> in POD. Of course, you'll have to process -.\" the output yourself in some meaningful fashion. -.if \nF \{\ -. de IX -. tm Index:\\$1\t\\n%\t"\\$2" -.. -. nr % 0 -. rr F -.\} -.\" -.\" For nroff, turn off justification. Always turn off hyphenation; it -.\" makes way too many mistakes in technical documents. -.hy 0 -.if n .na -.\" -.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2). -.\" Fear. Run. Save yourself. No user-serviceable parts. -.bd B 3 -. \" fudge factors for nroff and troff -.if n \{\ -. ds #H 0 -. ds #V .8m -. ds #F .3m -. ds #[ \f1 -. ds #] \fP -.\} -.if t \{\ -. ds #H ((1u-(\\\\n(.fu%2u))*.13m) -. ds #V .6m -. ds #F 0 -. ds #[ \& -. ds #] \& -.\} -. \" simple accents for nroff and troff -.if n \{\ -. ds ' \& -. ds ` \& -. ds ^ \& -. ds , \& -. ds ~ ~ -. ds / -.\} -.if t \{\ -. ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" -. ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' -. ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' -. ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' -. ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' -. ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' -.\} -. \" troff and (daisy-wheel) nroff accents -.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' -.ds 8 \h'\*(#H'\(*b\h'-\*(#H' -.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#] -.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H' -.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u' -.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#] -.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#] -.ds ae a\h'-(\w'a'u*4/10)'e -.ds Ae A\h'-(\w'A'u*4/10)'E -. \" corrections for vroff -.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u' -.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u' -. \" for low resolution devices (crt and lpr) -.if \n(.H>23 .if \n(.V>19 \ -\{\ -. ds : e -. ds 8 ss -. ds o a -. ds d- d\h'-1'\(ga -. ds D- D\h'-1'\(hy -. ds th \o'bp' -. ds Th \o'LP' -. ds ae ae -. ds Ae AE -.\} -.rm #[ #] #H #V #F C -.\" ====================================================================== -.\" -.IX Title "CPP 1" -.TH CPP 1 "gcc-3.2.2" "2003-02-05" "GNU" -.UC -.SH "NAME" -cpp \- The C Preprocessor -.SH "SYNOPSIS" -.IX Header "SYNOPSIS" -cpp [\fB\-D\fR\fImacro\fR[=\fIdefn\fR]...] [\fB\-U\fR\fImacro\fR] - [\fB\-I\fR\fIdir\fR...] [\fB\-W\fR\fIwarn\fR...] - [\fB\-M\fR|\fB\-MM\fR] [\fB\-MG\fR] [\fB\-MF\fR \fIfilename\fR] - [\fB\-MP\fR] [\fB\-MQ\fR \fItarget\fR...] [\fB\-MT\fR \fItarget\fR...] - [\fB\-x\fR \fIlanguage\fR] [\fB\-std=\fR\fIstandard\fR] - \fIinfile\fR \fIoutfile\fR -.PP -Only the most useful options are listed here; see below for the remainder. -.SH "DESCRIPTION" -.IX Header "DESCRIPTION" -The C preprocessor, often known as \fIcpp\fR, is a \fImacro processor\fR -that is used automatically by the C compiler to transform your program -before compilation. It is called a macro processor because it allows -you to define \fImacros\fR, which are brief abbreviations for longer -constructs. -.PP -The C preprocessor is intended to be used only with C, \*(C+, and -Objective-C source code. In the past, it has been abused as a general -text processor. It will choke on input which does not obey C's lexical -rules. For example, apostrophes will be interpreted as the beginning of -character constants, and cause errors. Also, you cannot rely on it -preserving characteristics of the input which are not significant to -C-family languages. If a Makefile is preprocessed, all the hard tabs -will be removed, and the Makefile will not work. -.PP -Having said that, you can often get away with using cpp on things which -are not C. Other Algol-ish programming languages are often safe -(Pascal, Ada, etc.) So is assembly, with caution. \fB\-traditional\fR -mode preserves more white space, and is otherwise more permissive. Many -of the problems can be avoided by writing C or \*(C+ style comments -instead of native language comments, and keeping macros simple. -.PP -Wherever possible, you should use a preprocessor geared to the language -you are writing in. Modern versions of the \s-1GNU\s0 assembler have macro -facilities. Most high level programming languages have their own -conditional compilation and inclusion mechanism. If all else fails, -try a true general text processor, such as \s-1GNU\s0 M4. -.PP -C preprocessors vary in some details. This manual discusses the \s-1GNU\s0 C -preprocessor, which provides a small superset of the features of \s-1ISO\s0 -Standard C. In its default mode, the \s-1GNU\s0 C preprocessor does not do a -few things required by the standard. These are features which are -rarely, if ever, used, and may cause surprising changes to the meaning -of a program which does not expect them. To get strict \s-1ISO\s0 Standard C, -you should use the \fB\-std=c89\fR or \fB\-std=c99\fR options, depending -on which version of the standard you want. To get all the mandatory -diagnostics, you must also use \fB\-pedantic\fR. -.SH "OPTIONS" -.IX Header "OPTIONS" -The C preprocessor expects two file names as arguments, \fIinfile\fR and -\&\fIoutfile\fR. The preprocessor reads \fIinfile\fR together with any -other files it specifies with \fB#include\fR. All the output generated -by the combined input files is written in \fIoutfile\fR. -.PP -Either \fIinfile\fR or \fIoutfile\fR may be \fB-\fR, which as -\&\fIinfile\fR means to read from standard input and as \fIoutfile\fR -means to write to standard output. Also, if either file is omitted, it -means the same as if \fB-\fR had been specified for that file. -.PP -Unless otherwise noted, or the option ends in \fB=\fR, all options -which take an argument may have that argument appear either immediately -after the option, or with a space between option and argument: -\&\fB\-Ifoo\fR and \fB\-I foo\fR have the same effect. -.PP -Many options have multi-letter names; therefore multiple single-letter -options may \fInot\fR be grouped: \fB\-dM\fR is very different from -\&\fB\-d\ \-M\fR. -.Ip "\fB\-D\fR \fIname\fR" 4 -.IX Item "-D name" -Predefine \fIname\fR as a macro, with definition \f(CW\*(C`1\*(C'\fR. -.Ip "\fB\-D\fR \fIname\fR\fB=\fR\fIdefinition\fR" 4 -.IX Item "-D name=definition" -Predefine \fIname\fR as a macro, with definition \fIdefinition\fR. -There are no restrictions on the contents of \fIdefinition\fR, but if -you are invoking the preprocessor from a shell or shell-like program you -may need to use the shell's quoting syntax to protect characters such as -spaces that have a meaning in the shell syntax. -.Sp -If you wish to define a function-like macro on the command line, write -its argument list with surrounding parentheses before the equals sign -(if any). Parentheses are meaningful to most shells, so you will need -to quote the option. With \fBsh\fR and \fBcsh\fR, -\&\fB\-D'\fR\fIname\fR\fB(\fR\fIargs...\fR\fB)=\fR\fIdefinition\fR\fB'\fR works. -.Sp -\&\fB\-D\fR and \fB\-U\fR options are processed in the order they -are given on the command line. All \fB\-imacros\fR \fIfile\fR and -\&\fB\-include\fR \fIfile\fR options are processed after all -\&\fB\-D\fR and \fB\-U\fR options. -.Ip "\fB\-U\fR \fIname\fR" 4 -.IX Item "-U name" -Cancel any previous definition of \fIname\fR, either built in or -provided with a \fB\-D\fR option. -.Ip "\fB\-undef\fR" 4 -.IX Item "-undef" -Do not predefine any system-specific macros. The common predefined -macros remain defined. -.Ip "\fB\-I\fR \fIdir\fR" 4 -.IX Item "-I dir" -Add the directory \fIdir\fR to the list of directories to be searched -for header files. -.Sp -Directories named by \fB\-I\fR are searched before the standard -system include directories. -.Sp -It is dangerous to specify a standard system include directory in an -\&\fB\-I\fR option. This defeats the special treatment of system -headers -\&. It can also defeat the repairs to buggy system headers which \s-1GCC\s0 -makes when it is installed. -.Ip "\fB\-o\fR \fIfile\fR" 4 -.IX Item "-o file" -Write output to \fIfile\fR. This is the same as specifying \fIfile\fR -as the second non-option argument to \fBcpp\fR. \fBgcc\fR has a -different interpretation of a second non-option argument, so you must -use \fB\-o\fR to specify the output file. -.Ip "\fB\-Wall\fR" 4 -.IX Item "-Wall" -Turns on all optional warnings which are desirable for normal code. At -present this is \fB\-Wcomment\fR and \fB\-Wtrigraphs\fR. Note that -many of the preprocessor's warnings are on by default and have no -options to control them. -.Ip "\fB\-Wcomment\fR" 4 -.IX Item "-Wcomment" -.PD 0 -.Ip "\fB\-Wcomments\fR" 4 -.IX Item "-Wcomments" -.PD -Warn whenever a comment-start sequence \fB/*\fR appears in a \fB/*\fR -comment, or whenever a backslash-newline appears in a \fB//\fR comment. -(Both forms have the same effect.) -.Ip "\fB\-Wtrigraphs\fR" 4 -.IX Item "-Wtrigraphs" -Warn if any trigraphs are encountered. This option used to take effect -only if \fB\-trigraphs\fR was also specified, but now works -independently. Warnings are not given for trigraphs within comments, as -they do not affect the meaning of the program. -.Ip "\fB\-Wtraditional\fR" 4 -.IX Item "-Wtraditional" -Warn about certain constructs that behave differently in traditional and -\&\s-1ISO\s0 C. Also warn about \s-1ISO\s0 C constructs that have no traditional C -equivalent, and problematic constructs which should be avoided. -.Ip "\fB\-Wimport\fR" 4 -.IX Item "-Wimport" -Warn the first time \fB#import\fR is used. -.Ip "\fB\-Wundef\fR" 4 -.IX Item "-Wundef" -Warn whenever an identifier which is not a macro is encountered in an -\&\fB#if\fR directive, outside of \fBdefined\fR. Such identifiers are -replaced with zero. -.Ip "\fB\-Werror\fR" 4 -.IX Item "-Werror" -Make all warnings into hard errors. Source code which triggers warnings -will be rejected. -.Ip "\fB\-Wsystem-headers\fR" 4 -.IX Item "-Wsystem-headers" -Issue warnings for code in system headers. These are normally unhelpful -in finding bugs in your own code, therefore suppressed. If you are -responsible for the system library, you may want to see them. -.Ip "\fB\-w\fR" 4 -.IX Item "-w" -Suppress all warnings, including those which \s-1GNU\s0 \s-1CPP\s0 issues by default. -.Ip "\fB\-pedantic\fR" 4 -.IX Item "-pedantic" -Issue all the mandatory diagnostics listed in the C standard. Some of -them are left out by default, since they trigger frequently on harmless -code. -.Ip "\fB\-pedantic-errors\fR" 4 -.IX Item "-pedantic-errors" -Issue all the mandatory diagnostics, and make all mandatory diagnostics -into errors. This includes mandatory diagnostics that \s-1GCC\s0 issues -without \fB\-pedantic\fR but treats as warnings. -.Ip "\fB\-M\fR" 4 -.IX Item "-M" -Instead of outputting the result of preprocessing, output a rule -suitable for \fBmake\fR describing the dependencies of the main -source file. The preprocessor outputs one \fBmake\fR rule containing -the object file name for that source file, a colon, and the names of all -the included files, including those coming from \fB\-include\fR or -\&\fB\-imacros\fR command line options. -.Sp -Unless specified explicitly (with \fB\-MT\fR or \fB\-MQ\fR), the -object file name consists of the basename of the source file with any -suffix replaced with object file suffix. If there are many included -files then the rule is split into several lines using \fB\e\fR\-newline. -The rule has no commands. -.Sp -This option does not suppress the preprocessor's debug output, such as -\&\fB\-dM\fR. To avoid mixing such debug output with the dependency -rules you should explicitly specify the dependency output file with -\&\fB\-MF\fR, or use an environment variable like -\&\fB\s-1DEPENDENCIES_OUTPUT\s0\fR. Debug output -will still be sent to the regular output stream as normal. -.Sp -Passing \fB\-M\fR to the driver implies \fB\-E\fR. -.Ip "\fB\-MM\fR" 4 -.IX Item "-MM" -Like \fB\-M\fR but do not mention header files that are found in -system header directories, nor header files that are included, -directly or indirectly, from such a header. -.Sp -This implies that the choice of angle brackets or double quotes in an -\&\fB#include\fR directive does not in itself determine whether that -header will appear in \fB\-MM\fR dependency output. This is a -slight change in semantics from \s-1GCC\s0 versions 3.0 and earlier. -.Ip "\fB\-MF\fR \fIfile\fR" 4 -.IX Item "-MF file" -@anchor{\-MF} -When used with \fB\-M\fR or \fB\-MM\fR, specifies a -file to write the dependencies to. If no \fB\-MF\fR switch is given -the preprocessor sends the rules to the same place it would have sent -preprocessed output. -.Sp -When used with the driver options \fB\-MD\fR or \fB\-MMD\fR, -\&\fB\-MF\fR overrides the default dependency output file. -.Ip "\fB\-MG\fR" 4 -.IX Item "-MG" -When used with \fB\-M\fR or \fB\-MM\fR, \fB\-MG\fR says to treat missing -header files as generated files and assume they live in the same -directory as the source file. It suppresses preprocessed output, as a -missing header file is ordinarily an error. -.Sp -This feature is used in automatic updating of makefiles. -.Ip "\fB\-MP\fR" 4 -.IX Item "-MP" -This option instructs \s-1CPP\s0 to add a phony target for each dependency -other than the main file, causing each to depend on nothing. These -dummy rules work around errors \fBmake\fR gives if you remove header -files without updating the \fIMakefile\fR to match. -.Sp -This is typical output: -.Sp -.Vb 1 -\& test.o: test.c test.h -.Ve -.Vb 1 -\& test.h: -.Ve -.Ip "\fB\-MT\fR \fItarget\fR" 4 -.IX Item "-MT target" -Change the target of the rule emitted by dependency generation. By -default \s-1CPP\s0 takes the name of the main input file, including any path, -deletes any file suffix such as \fB.c\fR, and appends the platform's -usual object suffix. The result is the target. -.Sp -An \fB\-MT\fR option will set the target to be exactly the string you -specify. If you want multiple targets, you can specify them as a single -argument to \fB\-MT\fR, or use multiple \fB\-MT\fR options. -.Sp -For example, \fB\-MT\ '$(objpfx)foo.o'\fR might give -.Sp -.Vb 1 -\& $(objpfx)foo.o: foo.c -.Ve -.Ip "\fB\-MQ\fR \fItarget\fR" 4 -.IX Item "-MQ target" -Same as \fB\-MT\fR, but it quotes any characters which are special to -Make. \fB\-MQ\ '$(objpfx)foo.o'\fR gives -.Sp -.Vb 1 -\& $$(objpfx)foo.o: foo.c -.Ve -The default target is automatically quoted, as if it were given with -\&\fB\-MQ\fR. -.Ip "\fB\-MD\fR" 4 -.IX Item "-MD" -\&\fB\-MD\fR is equivalent to \fB\-M \-MF\fR \fIfile\fR, except that -\&\fB\-E\fR is not implied. The driver determines \fIfile\fR based on -whether an \fB\-o\fR option is given. If it is, the driver uses its -argument but with a suffix of \fI.d\fR, otherwise it take the -basename of the input file and applies a \fI.d\fR suffix. -.Sp -If \fB\-MD\fR is used in conjunction with \fB\-E\fR, any -\&\fB\-o\fR switch is understood to specify the dependency output file -(but \f(CW@pxref\fR{\-MF}), but if used without \fB\-E\fR, each \fB\-o\fR -is understood to specify a target object file. -.Sp -Since \fB\-E\fR is not implied, \fB\-MD\fR can be used to generate -a dependency output file as a side-effect of the compilation process. -.Ip "\fB\-MMD\fR" 4 -.IX Item "-MMD" -Like \fB\-MD\fR except mention only user header files, not system -\&\-header files. -.Ip "\fB\-x c\fR" 4 -.IX Item "-x c" -.PD 0 -.Ip "\fB\-x c++\fR" 4 -.IX Item "-x c++" -.Ip "\fB\-x objective-c\fR" 4 -.IX Item "-x objective-c" -.Ip "\fB\-x assembler-with-cpp\fR" 4 -.IX Item "-x assembler-with-cpp" -.PD -Specify the source language: C, \*(C+, Objective-C, or assembly. This has -nothing to do with standards conformance or extensions; it merely -selects which base syntax to expect. If you give none of these options, -cpp will deduce the language from the extension of the source file: -\&\fB.c\fR, \fB.cc\fR, \fB.m\fR, or \fB.S\fR. Some other common -extensions for \*(C+ and assembly are also recognized. If cpp does not -recognize the extension, it will treat the file as C; this is the most -generic mode. -.Sp -\&\fBNote:\fR Previous versions of cpp accepted a \fB\-lang\fR option -which selected both the language and the standards conformance level. -This option has been removed, because it conflicts with the \fB\-l\fR -option. -.Ip "\fB\-std=\fR\fIstandard\fR" 4 -.IX Item "-std=standard" -.PD 0 -.Ip "\fB\-ansi\fR" 4 -.IX Item "-ansi" -.PD -Specify the standard to which the code should conform. Currently cpp -only knows about the standards for C; other language standards will be -added in the future. -.Sp -\&\fIstandard\fR -may be one of: -.RS 4 -.if n .Ip "\f(CW""""iso9899:1990""""\fR" 4 -.el .Ip "\f(CWiso9899:1990\fR" 4 -.IX Item "iso9899:1990" -.PD 0 -.if n .Ip "\f(CW""""c89""""\fR" 4 -.el .Ip "\f(CWc89\fR" 4 -.IX Item "c89" -.PD -The \s-1ISO\s0 C standard from 1990. \fBc89\fR is the customary shorthand for -this version of the standard. -.Sp -The \fB\-ansi\fR option is equivalent to \fB\-std=c89\fR. -.if n .Ip "\f(CW""""iso9899:199409""""\fR" 4 -.el .Ip "\f(CWiso9899:199409\fR" 4 -.IX Item "iso9899:199409" -The 1990 C standard, as amended in 1994. -.if n .Ip "\f(CW""""iso9899:1999""""\fR" 4 -.el .Ip "\f(CWiso9899:1999\fR" 4 -.IX Item "iso9899:1999" -.PD 0 -.if n .Ip "\f(CW""""c99""""\fR" 4 -.el .Ip "\f(CWc99\fR" 4 -.IX Item "c99" -.if n .Ip "\f(CW""""iso9899:199x""""\fR" 4 -.el .Ip "\f(CWiso9899:199x\fR" 4 -.IX Item "iso9899:199x" -.if n .Ip "\f(CW""""c9x""""\fR" 4 -.el .Ip "\f(CWc9x\fR" 4 -.IX Item "c9x" -.PD -The revised \s-1ISO\s0 C standard, published in December 1999. Before -publication, this was known as C9X. -.if n .Ip "\f(CW""""gnu89""""\fR" 4 -.el .Ip "\f(CWgnu89\fR" 4 -.IX Item "gnu89" -The 1990 C standard plus \s-1GNU\s0 extensions. This is the default. -.if n .Ip "\f(CW""""gnu99""""\fR" 4 -.el .Ip "\f(CWgnu99\fR" 4 -.IX Item "gnu99" -.PD 0 -.if n .Ip "\f(CW""""gnu9x""""\fR" 4 -.el .Ip "\f(CWgnu9x\fR" 4 -.IX Item "gnu9x" -.PD -The 1999 C standard plus \s-1GNU\s0 extensions. -.RE -.RS 4 -.RE -.Ip "\fB\-I-\fR" 4 -.IX Item "-I-" -Split the include path. Any directories specified with \fB\-I\fR -options before \fB\-I-\fR are searched only for headers requested with -\&\f(CW\*(C`#include\ "\f(CIfile\f(CW"\*(C'\fR; they are not searched for -\&\f(CW\*(C`#include\ <\f(CIfile\f(CW>\*(C'\fR. If additional directories are -specified with \fB\-I\fR options after the \fB\-I-\fR, those -directories are searched for all \fB#include\fR directives. -.Sp -In addition, \fB\-I-\fR inhibits the use of the directory of the current -file directory as the first search directory for \f(CW\*(C`#include\ "\f(CIfile\f(CW"\*(C'\fR. -.Ip "\fB\-nostdinc\fR" 4 -.IX Item "-nostdinc" -Do not search the standard system directories for header files. -Only the directories you have specified with \fB\-I\fR options -(and the directory of the current file, if appropriate) are searched. -.Ip "\fB\-nostdinc++\fR" 4 -.IX Item "-nostdinc++" -Do not search for header files in the \*(C+\-specific standard directories, -but do still search the other standard directories. (This option is -used when building the \*(C+ library.) -.Ip "\fB\-include\fR \fIfile\fR" 4 -.IX Item "-include file" -Process \fIfile\fR as if \f(CW\*(C`#include "file"\*(C'\fR appeared as the first -line of the primary source file. However, the first directory searched -for \fIfile\fR is the preprocessor's working directory \fIinstead of\fR -the directory containing the main source file. If not found there, it -is searched for in the remainder of the \f(CW\*(C`#include "..."\*(C'\fR search -chain as normal. -.Sp -If multiple \fB\-include\fR options are given, the files are included -in the order they appear on the command line. -.Ip "\fB\-imacros\fR \fIfile\fR" 4 -.IX Item "-imacros file" -Exactly like \fB\-include\fR, except that any output produced by -scanning \fIfile\fR is thrown away. Macros it defines remain defined. -This allows you to acquire all the macros from a header without also -processing its declarations. -.Sp -All files specified by \fB\-imacros\fR are processed before all files -specified by \fB\-include\fR. -.Ip "\fB\-idirafter\fR \fIdir\fR" 4 -.IX Item "-idirafter dir" -Search \fIdir\fR for header files, but do it \fIafter\fR all -directories specified with \fB\-I\fR and the standard system directories -have been exhausted. \fIdir\fR is treated as a system include directory. -.Ip "\fB\-iprefix\fR \fIprefix\fR" 4 -.IX Item "-iprefix prefix" -Specify \fIprefix\fR as the prefix for subsequent \fB\-iwithprefix\fR -options. If the prefix represents a directory, you should include the -final \fB/\fR. -.Ip "\fB\-iwithprefix\fR \fIdir\fR" 4 -.IX Item "-iwithprefix dir" -.PD 0 -.Ip "\fB\-iwithprefixbefore\fR \fIdir\fR" 4 -.IX Item "-iwithprefixbefore dir" -.PD -Append \fIdir\fR to the prefix specified previously with -\&\fB\-iprefix\fR, and add the resulting directory to the include search -path. \fB\-iwithprefixbefore\fR puts it in the same place \fB\-I\fR -would; \fB\-iwithprefix\fR puts it where \fB\-idirafter\fR would. -.Sp -Use of these options is discouraged. -.Ip "\fB\-isystem\fR \fIdir\fR" 4 -.IX Item "-isystem dir" -Search \fIdir\fR for header files, after all directories specified by -\&\fB\-I\fR but before the standard system directories. Mark it -as a system directory, so that it gets the same special treatment as -is applied to the standard system directories. -.Ip "\fB\-fpreprocessed\fR" 4 -.IX Item "-fpreprocessed" -Indicate to the preprocessor that the input file has already been -preprocessed. This suppresses things like macro expansion, trigraph -conversion, escaped newline splicing, and processing of most directives. -The preprocessor still recognizes and removes comments, so that you can -pass a file preprocessed with \fB\-C\fR to the compiler without -problems. In this mode the integrated preprocessor is little more than -a tokenizer for the front ends. -.Sp -\&\fB\-fpreprocessed\fR is implicit if the input file has one of the -extensions \fB.i\fR, \fB.ii\fR or \fB.mi\fR. These are the -extensions that \s-1GCC\s0 uses for preprocessed files created by -\&\fB\-save-temps\fR. -.Ip "\fB\-ftabstop=\fR\fIwidth\fR" 4 -.IX Item "-ftabstop=width" -Set the distance between tab stops. This helps the preprocessor report -correct column numbers in warnings or errors, even if tabs appear on the -line. If the value is less than 1 or greater than 100, the option is -ignored. The default is 8. -.Ip "\fB\-fno-show-column\fR" 4 -.IX Item "-fno-show-column" -Do not print column numbers in diagnostics. This may be necessary if -diagnostics are being scanned by a program that does not understand the -column numbers, such as \fBdejagnu\fR. -.Ip "\fB\-A\fR \fIpredicate\fR\fB=\fR\fIanswer\fR" 4 -.IX Item "-A predicate=answer" -Make an assertion with the predicate \fIpredicate\fR and answer -\&\fIanswer\fR. This form is preferred to the older form \fB\-A\fR -\&\fIpredicate\fR\fB(\fR\fIanswer\fR\fB)\fR, which is still supported, because -it does not use shell special characters. -.Ip "\fB\-A -\fR\fIpredicate\fR\fB=\fR\fIanswer\fR" 4 -.IX Item "-A -predicate=answer" -Cancel an assertion with the predicate \fIpredicate\fR and answer -\&\fIanswer\fR. -.Ip "\fB\-A-\fR" 4 -.IX Item "-A-" -Cancel all predefined assertions and all assertions preceding it on -the command line. Also, undefine all predefined macros and all -macros preceding it on the command line. (This is a historical wart and -may change in the future.) -.Ip "\fB\-dCHARS\fR" 4 -.IX Item "-dCHARS" -\&\fI\s-1CHARS\s0\fR is a sequence of one or more of the following characters, -and must not be preceded by a space. Other characters are interpreted -by the compiler proper, or reserved for future versions of \s-1GCC\s0, and so -are silently ignored. If you specify characters whose behavior -conflicts, the result is undefined. -.RS 4 -.Ip "\fBM\fR" 4 -.IX Item "M" -Instead of the normal output, generate a list of \fB#define\fR -directives for all the macros defined during the execution of the -preprocessor, including predefined macros. This gives you a way of -finding out what is predefined in your version of the preprocessor. -Assuming you have no file \fIfoo.h\fR, the command -.Sp -.Vb 1 -\& touch foo.h; cpp -dM foo.h -.Ve -will show all the predefined macros. -.Ip "\fBD\fR" 4 -.IX Item "D" -Like \fBM\fR except in two respects: it does \fInot\fR include the -predefined macros, and it outputs \fIboth\fR the \fB#define\fR -directives and the result of preprocessing. Both kinds of output go to -the standard output file. -.Ip "\fBN\fR" 4 -.IX Item "N" -Like \fBD\fR, but emit only the macro names, not their expansions. -.Ip "\fBI\fR" 4 -.IX Item "I" -Output \fB#include\fR directives in addition to the result of -preprocessing. -.RE -.RS 4 -.RE -.Ip "\fB\-P\fR" 4 -.IX Item "-P" -Inhibit generation of linemarkers in the output from the preprocessor. -This might be useful when running the preprocessor on something that is -not C code, and will be sent to a program which might be confused by the -linemarkers. -.Ip "\fB\-C\fR" 4 -.IX Item "-C" -Do not discard comments. All comments are passed through to the output -file, except for comments in processed directives, which are deleted -along with the directive. -.Sp -You should be prepared for side effects when using \fB\-C\fR; it -causes the preprocessor to treat comments as tokens in their own right. -For example, comments appearing at the start of what would be a -directive line have the effect of turning that line into an ordinary -source line, since the first token on the line is no longer a \fB#\fR. -.Ip "\fB\-gcc\fR" 4 -.IX Item "-gcc" -Define the macros _\|_GNUC_\|_, _\|_GNUC_MINOR_\|_ and -_\|_GNUC_PATCHLEVEL_\|_. These are defined automatically when you use -\&\fBgcc \-E\fR; you can turn them off in that case with -\&\fB\-no-gcc\fR. -.Ip "\fB\-traditional\fR" 4 -.IX Item "-traditional" -Try to imitate the behavior of old-fashioned C, as opposed to \s-1ISO\s0 -C. -.Ip "\fB\-trigraphs\fR" 4 -.IX Item "-trigraphs" -Process trigraph sequences. -.Ip "\fB\-remap\fR" 4 -.IX Item "-remap" -Enable special code to work around file systems which only permit very -short file names, such as \s-1MS-DOS\s0. -.Ip "\fB\-$\fR" 4 -.IX Item "-$" -Forbid the use of \fB$\fR in identifiers. The C standard allows -implementations to define extra characters that can appear in -identifiers. By default \s-1GNU\s0 \s-1CPP\s0 permits \fB$\fR, a common extension. -.Ip "\fB\-h\fR" 4 -.IX Item "-h" -.PD 0 -.Ip "\fB\*(--help\fR" 4 -.IX Item "help" -.Ip "\fB\*(--target-help\fR" 4 -.IX Item "target-help" -.PD -Print text describing all the command line options instead of -preprocessing anything. -.Ip "\fB\-v\fR" 4 -.IX Item "-v" -Verbose mode. Print out \s-1GNU\s0 \s-1CPP\s0's version number at the beginning of -execution, and report the final form of the include path. -.Ip "\fB\-H\fR" 4 -.IX Item "-H" -Print the name of each header file used, in addition to other normal -activities. Each name is indented to show how deep in the -\&\fB#include\fR stack it is. -.Ip "\fB\-version\fR" 4 -.IX Item "-version" -.PD 0 -.Ip "\fB\*(--version\fR" 4 -.IX Item "version" -.PD -Print out \s-1GNU\s0 \s-1CPP\s0's version number. With one dash, proceed to -preprocess as normal. With two dashes, exit immediately. -.SH "ENVIRONMENT" -.IX Header "ENVIRONMENT" -This section describes the environment variables that affect how \s-1CPP\s0 -operates. You can use them to specify directories or prefixes to use -when searching for include files, or to control dependency output. -.PP -Note that you can also specify places to search using options such as -\&\fB\-I\fR, and control dependency output with options like -\&\fB\-M\fR. These take precedence over -environment variables, which in turn take precedence over the -configuration of \s-1GCC\s0. -.Ip "\fB\s-1CPATH\s0\fR" 4 -.IX Item "CPATH" -.PD 0 -.Ip "\fBC_INCLUDE_PATH\fR" 4 -.IX Item "C_INCLUDE_PATH" -.Ip "\fB\s-1CPLUS_INCLUDE_PATH\s0\fR" 4 -.IX Item "CPLUS_INCLUDE_PATH" -.Ip "\fB\s-1OBJC_INCLUDE_PATH\s0\fR" 4 -.IX Item "OBJC_INCLUDE_PATH" -.PD -Each variable's value is a list of directories separated by a special -character, much like \fB\s-1PATH\s0\fR, in which to look for header files. -The special character, \f(CW\*(C`PATH_SEPARATOR\*(C'\fR, is target-dependent and -determined at \s-1GCC\s0 build time. For Windows-based targets it is a -semicolon, and for almost all other targets it is a colon. -.Sp -\&\fB\s-1CPATH\s0\fR specifies a list of directories to be searched as if -specified with \fB\-I\fR, but after any paths given with \fB\-I\fR -options on the command line. The environment variable is used -regardless of which language is being preprocessed. -.Sp -The remaining environment variables apply only when preprocessing the -particular language indicated. Each specifies a list of directories -to be searched as if specified with \fB\-isystem\fR, but after any -paths given with \fB\-isystem\fR options on the command line. -.Sp -See also \f(CW@ref\fR{Search Path}. -.Ip "\fB\s-1DEPENDENCIES_OUTPUT\s0\fR" 4 -.IX Item "DEPENDENCIES_OUTPUT" -@anchor{\s-1DEPENDENCIES_OUTPUT\s0} -If this variable is set, its value specifies how to output -dependencies for Make based on the non-system header files processed -by the compiler. System header files are ignored in the dependency -output. -.Sp -The value of \fB\s-1DEPENDENCIES_OUTPUT\s0\fR can be just a file name, in -which case the Make rules are written to that file, guessing the target -name from the source file name. Or the value can have the form -\&\fIfile\fR\fB \fR\fItarget\fR, in which case the rules are written to -file \fIfile\fR using \fItarget\fR as the target name. -.Sp -In other words, this environment variable is equivalent to combining -the options \fB\-MM\fR and \fB\-MF\fR, -with an optional \fB\-MT\fR switch too. -.Ip "\fB\s-1SUNPRO_DEPENDENCIES\s0\fR" 4 -.IX Item "SUNPRO_DEPENDENCIES" -This variable is the same as the environment variable -\&\fB\s-1DEPENDENCIES_OUTPUT\s0\fR, except that -system header files are not ignored, so it implies \fB\-M\fR rather -than \fB\-MM\fR. However, the dependence on the main input file is -omitted. -.SH "SEE ALSO" -.IX Header "SEE ALSO" -\&\fIgpl\fR\|(7), \fIgfdl\fR\|(7), \fIfsf-funding\fR\|(7), -\&\fIgcc\fR\|(1), \fIas\fR\|(1), \fIld\fR\|(1), and the Info entries for \fIcpp\fR, \fIgcc\fR, and -\&\fIbinutils\fR. -.SH "COPYRIGHT" -.IX Header "COPYRIGHT" -Copyright (c) 1987, 1989, 1991, 1992, 1993, 1994, 1995, 1996, -1997, 1998, 1999, 2000, 2001 -Free Software Foundation, Inc. -.PP -Permission is granted to copy, distribute and/or modify this document -under the terms of the \s-1GNU\s0 Free Documentation License, Version 1.1 or -any later version published by the Free Software Foundation. A copy of -the license is included in the -man page \fIgfdl\fR\|(7). -This manual contains no Invariant Sections. The Front-Cover Texts are -(a) (see below), and the Back-Cover Texts are (b) (see below). -.PP -(a) The \s-1FSF\s0's Front-Cover Text is: -.PP -.Vb 1 -\& A GNU Manual -.Ve -(b) The \s-1FSF\s0's Back-Cover Text is: -.PP -.Vb 3 -\& You have freedom to copy and modify this GNU Manual, like GNU -\& software. Copies published by the Free Software Foundation raise -\& funds for GNU development. -.Ve diff --git a/contrib/gcc/doc/gcc.1 b/contrib/gcc/doc/gcc.1 deleted file mode 100644 index 16a2b28300fd..000000000000 --- a/contrib/gcc/doc/gcc.1 +++ /dev/null @@ -1,9464 +0,0 @@ -.\" Automatically generated by Pod::Man version 1.15 -.\" Wed Feb 5 03:13:56 2003 -.\" -.\" Standard preamble: -.\" ====================================================================== -.de Sh \" Subsection heading -.br -.if t .Sp -.ne 5 -.PP -\fB\\$1\fR -.PP -.. -.de Sp \" Vertical space (when we can't use .PP) -.if t .sp .5v -.if n .sp -.. -.de Ip \" List item -.br -.ie \\n(.$>=3 .ne \\$3 -.el .ne 3 -.IP "\\$1" \\$2 -.. -.de Vb \" Begin verbatim text -.ft CW -.nf -.ne \\$1 -.. -.de Ve \" End verbatim text -.ft R - -.fi -.. -.\" Set up some character translations and predefined strings. \*(-- will -.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left -.\" double quote, and \*(R" will give a right double quote. | will give a -.\" real vertical bar. \*(C+ will give a nicer C++. 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The ``overall options'' allow you to stop this -process at an intermediate stage. For example, the \fB\-c\fR option -says not to run the linker. Then the output consists of object files -output by the assembler. -.PP -Other options are passed on to one stage of processing. Some options -control the preprocessor and others the compiler itself. Yet other -options control the assembler and linker; most of these are not -documented here, since you rarely need to use any of them. -.PP -Most of the command line options that you can use with \s-1GCC\s0 are useful -for C programs; when an option is only useful with another language -(usually \*(C+), the explanation says so explicitly. If the description -for a particular option does not mention a source language, you can use -that option with all supported languages. -.PP -The \fBgcc\fR program accepts options and file names as operands. Many -options have multi-letter names; therefore multiple single-letter options -may \fInot\fR be grouped: \fB\-dr\fR is very different from \fB\-d\ \-r\fR. -.PP -You can mix options and other arguments. For the most part, the order -you use doesn't matter. Order does matter when you use several options -of the same kind; for example, if you specify \fB\-L\fR more than once, -the directories are searched in the order specified. -.PP -Many options have long names starting with \fB\-f\fR or with -\&\fB\-W\fR\-\-\-for example, \fB\-fforce-mem\fR, -\&\fB\-fstrength-reduce\fR, \fB\-Wformat\fR and so on. Most of -these have both positive and negative forms; the negative form of -\&\fB\-ffoo\fR would be \fB\-fno-foo\fR. This manual documents -only one of these two forms, whichever one is not the default. -.SH "OPTIONS" -.IX Header "OPTIONS" -.Sh "Option Summary" -.IX Subsection "Option Summary" -Here is a summary of all the options, grouped by type. Explanations are -in the following sections. -.Ip "\fIOverall Options\fR" 4 -.IX Item "Overall Options" -\&\fB\-c \-S \-E \-o\fR \fIfile\fR \fB\-pipe \-pass-exit-codes \-x\fR \fIlanguage\fR -\&\fB\-v \-### \-\-help \-\-target-help \-\-version\fR -.Ip "\fIC Language Options\fR" 4 -.IX Item "C Language Options" -\&\fB\-ansi \-std=\fR\fIstandard\fR \fB\-aux-info\fR \fIfilename\fR -\&\fB\-fno-asm \-fno-builtin \-fno-builtin-\fR\fIfunction\fR -\&\fB\-fhosted \-ffreestanding -\&\-trigraphs \-no-integrated-cpp \-traditional \-traditional-cpp -\&\-fallow-single-precision \-fcond-mismatch -\&\-fsigned-bitfields \-fsigned-char -\&\-funsigned-bitfields \-funsigned-char -\&\-fwritable-strings\fR -.Ip "\fI\*(C+ Language Options\fR" 4 -.IX Item " Language Options" -\&\fB\-fno-access-control \-fcheck-new \-fconserve-space -\&\-fno-const-strings \-fdollars-in-identifiers -\&\-fno-elide-constructors -\&\-fno-enforce-eh-specs \-fexternal-templates -\&\-falt-external-templates -\&\-ffor-scope \-fno-for-scope \-fno-gnu-keywords -\&\-fno-implicit-templates -\&\-fno-implicit-inline-templates -\&\-fno-implement-inlines \-fms-extensions -\&\-fno-nonansi-builtins \-fno-operator-names -\&\-fno-optional-diags \-fpermissive -\&\-frepo \-fno-rtti \-fstats \-ftemplate-depth-\fR\fIn\fR -\&\fB\-fuse-cxa-atexit \-fvtable-gc \-fno-weak \-nostdinc++ -\&\-fno-default-inline \-Wabi \-Wctor-dtor-privacy -\&\-Wnon-virtual-dtor \-Wreorder -\&\-Weffc++ \-Wno-deprecated -\&\-Wno-non-template-friend \-Wold-style-cast -\&\-Woverloaded-virtual \-Wno-pmf-conversions -\&\-Wsign-promo \-Wsynth\fR -.Ip "\fIObjective-C Language Options\fR" 4 -.IX Item "Objective-C Language Options" -\&\fB\-fconstant-string-class=\fR\fIclass-name\fR -\&\fB\-fgnu-runtime \-fnext-runtime \-gen-decls -\&\-Wno-protocol \-Wselector\fR -.Ip "\fILanguage Independent Options\fR" 4 -.IX Item "Language Independent Options" -\&\fB\-fmessage-length=\fR\fIn\fR -\&\fB\-fdiagnostics-show-location=\fR[\fBonce\fR|\fBevery-line\fR] -.Ip "\fIWarning Options\fR" 4 -.IX Item "Warning Options" -\&\fB\-fsyntax-only \-pedantic \-pedantic-errors -\&\-w \-W \-Wall \-Waggregate-return -\&\-Wcast-align \-Wcast-qual \-Wchar-subscripts \-Wcomment -\&\-Wconversion \-Wno-deprecated-declarations -\&\-Wdisabled-optimization \-Wdiv-by-zero \-Werror -\&\-Wfloat-equal \-Wformat \-Wformat=2 -\&\-Wformat-nonliteral \-Wformat-security -\&\-Wimplicit \-Wimplicit-int -\&\-Wimplicit-function-declaration -\&\-Werror-implicit-function-declaration -\&\-Wimport \-Winline -\&\-Wlarger-than-\fR\fIlen\fR \fB\-Wlong-long -\&\-Wmain \-Wmissing-braces -\&\-Wmissing-format-attribute \-Wmissing-noreturn -\&\-Wmultichar \-Wno-format-extra-args \-Wno-format-y2k -\&\-Wno-import \-Wpacked \-Wpadded -\&\-Wparentheses \-Wpointer-arith \-Wredundant-decls -\&\-Wreturn-type \-Wsequence-point \-Wshadow -\&\-Wsign-compare \-Wswitch \-Wsystem-headers -\&\-Wtrigraphs \-Wundef \-Wuninitialized -\&\-Wunknown-pragmas \-Wunreachable-code -\&\-Wunused \-Wunused-function \-Wunused-label \-Wunused-parameter -\&\-Wunused-value \-Wunused-variable \-Wwrite-strings\fR -.Ip "\fIC-only Warning Options\fR" 4 -.IX Item "C-only Warning Options" -\&\fB\-Wbad-function-cast \-Wmissing-declarations -\&\-Wmissing-prototypes \-Wnested-externs -\&\-Wstrict-prototypes \-Wtraditional\fR -.Ip "\fIDebugging Options\fR" 4 -.IX Item "Debugging Options" -\&\fB\-d\fR\fIletters\fR \fB\-dumpspecs \-dumpmachine \-dumpversion -\&\-fdump-unnumbered \-fdump-translation-unit\fR[\fB-\fR\fIn\fR] -\&\fB\-fdump-class-hierarchy\fR[\fB-\fR\fIn\fR] -\&\fB\-fdump-tree-original\fR[\fB-\fR\fIn\fR] \fB\-fdump-tree-optimized\fR[\fB-\fR\fIn\fR] -\&\fB\-fdump-tree-inlined\fR[\fB-\fR\fIn\fR] -\&\fB\-fmem-report \-fpretend-float -\&\-fprofile-arcs \-fsched-verbose=\fR\fIn\fR -\&\fB\-ftest-coverage \-ftime-report -\&\-g \-g\fR\fIlevel\fR \fB\-gcoff \-gdwarf \-gdwarf-1 \-gdwarf-1+ \-gdwarf-2 -\&\-ggdb \-gstabs \-gstabs+ \-gvms \-gxcoff \-gxcoff+ -\&\-p \-pg \-print-file-name=\fR\fIlibrary\fR \fB\-print-libgcc-file-name -\&\-print-multi-directory \-print-multi-lib -\&\-print-prog-name=\fR\fIprogram\fR \fB\-print-search-dirs \-Q -\&\-save-temps \-time\fR -.Ip "\fIOptimization Options\fR" 4 -.IX Item "Optimization Options" -\&\fB\-falign-functions=\fR\fIn\fR \fB\-falign-jumps=\fR\fIn\fR -\&\fB\-falign-labels=\fR\fIn\fR \fB\-falign-loops=\fR\fIn\fR -\&\fB\-fbounds-check -\&\-fbranch-probabilities \-fcaller-saves \-fcprop-registers -\&\-fcse-follow-jumps \-fcse-skip-blocks \-fdata-sections -\&\-fdelayed-branch \-fdelete-null-pointer-checks -\&\-fexpensive-optimizations \-ffast-math \-ffloat-store -\&\-fforce-addr \-fforce-mem \-ffunction-sections -\&\-fgcse \-fgcse-lm \-fgcse-sm -\&\-finline-functions \-finline-limit=\fR\fIn\fR \fB\-fkeep-inline-functions -\&\-fkeep-static-consts \-fmerge-constants \-fmerge-all-constants -\&\-fmove-all-movables \-fno-branch-count-reg -\&\-fno-default-inline \-fno-defer-pop -\&\-fno-function-cse \-fno-guess-branch-probability -\&\-fno-inline \-fno-math-errno \-fno-peephole \-fno-peephole2 -\&\-funsafe-math-optimizations \-fno-trapping-math -\&\-fomit-frame-pointer \-foptimize-register-move -\&\-foptimize-sibling-calls \-fprefetch-loop-arrays -\&\-freduce-all-givs \-fregmove \-frename-registers -\&\-frerun-cse-after-loop \-frerun-loop-opt -\&\-fschedule-insns \-fschedule-insns2 -\&\-fno-sched-interblock \-fno-sched-spec -\&\-fsched-spec-load \-fsched-spec-load-dangerous -\&\-fsingle-precision-constant \-fssa \-fssa-ccp \-fssa-dce -\&\-fstrength-reduce \-fstrict-aliasing \-fthread-jumps -\&\-ftrapv \-funroll-all-loops \-funroll-loops -\&\-\-param\fR \fIname\fR\fB=\fR\fIvalue\fR -\&\fB\-O \-O0 \-O1 \-O2 \-O3 \-Os\fR -.Ip "\fIPreprocessor Options\fR" 4 -.IX Item "Preprocessor Options" -\&\fB\-$ \-A\fR\fIquestion\fR\fB=\fR\fIanswer\fR \fB\-A-\fR\fIquestion\fR[\fB=\fR\fIanswer\fR] -\&\fB\-C \-dD \-dI \-dM \-dN -\&\-D\fR\fImacro\fR[\fB=\fR\fIdefn\fR] \fB\-E \-H -\&\-idirafter\fR \fIdir\fR -\&\fB\-include\fR \fIfile\fR \fB\-imacros\fR \fIfile\fR -\&\fB\-iprefix\fR \fIfile\fR \fB\-iwithprefix\fR \fIdir\fR -\&\fB\-iwithprefixbefore\fR \fIdir\fR \fB\-isystem\fR \fIdir\fR -\&\fB\-M \-MM \-MF \-MG \-MP \-MQ \-MT \-nostdinc \-P \-remap -\&\-trigraphs \-undef \-U\fR\fImacro\fR \fB\-Wp,\fR\fIoption\fR -.Ip "\fIAssembler Option\fR" 4 -.IX Item "Assembler Option" -\&\fB\-Wa,\fR\fIoption\fR -.Ip "\fILinker Options\fR" 4 -.IX Item "Linker Options" -\&\fB -\&\fR\fIobject-file-name\fR \fB\-l\fR\fIlibrary\fR -\&\fB\-nostartfiles \-nodefaultlibs \-nostdlib -\&\-s \-static \-static-libgcc \-shared \-shared-libgcc \-symbolic -\&\-Wl,\fR\fIoption\fR \fB\-Xlinker\fR \fIoption\fR -\&\fB\-u\fR \fIsymbol\fR -.Ip "\fIDirectory Options\fR" 4 -.IX Item "Directory Options" -\&\fB\-B\fR\fIprefix\fR \fB\-I\fR\fIdir\fR \fB\-I- \-L\fR\fIdir\fR \fB\-specs=\fR\fIfile\fR -.Ip "\fITarget Options\fR" 4 -.IX Item "Target Options" -\&\fB\-b\fR \fImachine\fR \fB\-V\fR \fIversion\fR -.Ip "\fIMachine Dependent Options\fR" 4 -.IX Item "Machine Dependent Options" -\&\fIM680x0 Options\fR -.Sp -\&\fB\-m68000 \-m68020 \-m68020\-40 \-m68020\-60 \-m68030 \-m68040 -\&\-m68060 \-mcpu32 \-m5200 \-m68881 \-mbitfield \-mc68000 \-mc68020 -\&\-mfpa \-mnobitfield \-mrtd \-mshort \-msoft-float \-mpcrel -\&\-malign-int \-mstrict-align\fR -.Sp -\&\fIM68hc1x Options\fR -.Sp -\&\fB\-m6811 \-m6812 \-m68hc11 \-m68hc12 -\&\-mauto-incdec \-mshort \-msoft-reg-count=\fR\fIcount\fR -.Sp -\&\fI\s-1VAX\s0 Options\fR -.Sp -\&\fB\-mg \-mgnu \-munix\fR -.Sp -\&\fI\s-1SPARC\s0 Options\fR -.Sp -\&\fB\-mcpu=\fR\fIcpu-type\fR -\&\fB\-mtune=\fR\fIcpu-type\fR -\&\fB\-mcmodel=\fR\fIcode-model\fR -\&\fB\-m32 \-m64 -\&\-mapp-regs \-mbroken-saverestore \-mcypress -\&\-mfaster-structs \-mflat -\&\-mfpu \-mhard-float \-mhard-quad-float -\&\-mimpure-text \-mlive-g0 \-mno-app-regs -\&\-mno-faster-structs \-mno-flat \-mno-fpu -\&\-mno-impure-text \-mno-stack-bias \-mno-unaligned-doubles -\&\-msoft-float \-msoft-quad-float \-msparclite \-mstack-bias -\&\-msupersparc \-munaligned-doubles \-mv8\fR -.Sp -\&\fIConvex Options\fR -.Sp -\&\fB\-mc1 \-mc2 \-mc32 \-mc34 \-mc38 -\&\-margcount \-mnoargcount -\&\-mlong32 \-mlong64 -\&\-mvolatile-cache \-mvolatile-nocache\fR -.Sp -\&\fI\s-1AMD29K\s0 Options\fR -.Sp -\&\fB\-m29000 \-m29050 \-mbw \-mnbw \-mdw \-mndw -\&\-mlarge \-mnormal \-msmall -\&\-mkernel-registers \-mno-reuse-arg-regs -\&\-mno-stack-check \-mno-storem-bug -\&\-mreuse-arg-regs \-msoft-float \-mstack-check -\&\-mstorem-bug \-muser-registers\fR -.Sp -\&\fI\s-1ARM\s0 Options\fR -.Sp -\&\fB\-mapcs-frame \-mno-apcs-frame -\&\-mapcs-26 \-mapcs-32 -\&\-mapcs-stack-check \-mno-apcs-stack-check -\&\-mapcs-float \-mno-apcs-float -\&\-mapcs-reentrant \-mno-apcs-reentrant -\&\-msched-prolog \-mno-sched-prolog -\&\-mlittle-endian \-mbig-endian \-mwords-little-endian -\&\-malignment-traps \-mno-alignment-traps -\&\-msoft-float \-mhard-float \-mfpe -\&\-mthumb-interwork \-mno-thumb-interwork -\&\-mcpu=\fR\fIname\fR \fB\-march=\fR\fIname\fR \fB\-mfpe=\fR\fIname\fR -\&\fB\-mstructure-size-boundary=\fR\fIn\fR -\&\fB\-mbsd \-mxopen \-mno-symrename -\&\-mabort-on-noreturn -\&\-mlong-calls \-mno-long-calls -\&\-msingle-pic-base \-mno-single-pic-base -\&\-mpic-register=\fR\fIreg\fR -\&\fB\-mnop-fun-dllimport -\&\-mpoke-function-name -\&\-mthumb \-marm -\&\-mtpcs-frame \-mtpcs-leaf-frame -\&\-mcaller-super-interworking \-mcallee-super-interworking\fR -.Sp -\&\fI\s-1MN10200\s0 Options\fR -.Sp -\&\fB\-mrelax\fR -.Sp -\&\fI\s-1MN10300\s0 Options\fR -.Sp -\&\fB\-mmult-bug \-mno-mult-bug -\&\-mam33 \-mno-am33 -\&\-mno-crt0 \-mrelax\fR -.Sp -\&\fIM32R/D Options\fR -.Sp -\&\fB\-m32rx \-m32r \-mcode-model=\fR\fImodel-type\fR \fB\-msdata=\fR\fIsdata-type\fR -\&\fB\-G\fR \fInum\fR -.Sp -\&\fIM88K Options\fR -.Sp -\&\fB\-m88000 \-m88100 \-m88110 \-mbig-pic -\&\-mcheck-zero-division \-mhandle-large-shift -\&\-midentify-revision \-mno-check-zero-division -\&\-mno-ocs-debug-info \-mno-ocs-frame-position -\&\-mno-optimize-arg-area \-mno-serialize-volatile -\&\-mno-underscores \-mocs-debug-info -\&\-mocs-frame-position \-moptimize-arg-area -\&\-mserialize-volatile \-mshort-data-\fR\fInum\fR \fB\-msvr3 -\&\-msvr4 \-mtrap-large-shift \-muse-div-instruction -\&\-mversion-03.00 \-mwarn-passed-structs\fR -.Sp -\&\fI\s-1RS/6000\s0 and PowerPC Options\fR -.Sp -\&\fB\-mcpu=\fR\fIcpu-type\fR -\&\fB\-mtune=\fR\fIcpu-type\fR -\&\fB\-mpower \-mno-power \-mpower2 \-mno-power2 -\&\-mpowerpc \-mpowerpc64 \-mno-powerpc -\&\-maltivec \-mno-altivec -\&\-mpowerpc-gpopt \-mno-powerpc-gpopt -\&\-mpowerpc-gfxopt \-mno-powerpc-gfxopt -\&\-mnew-mnemonics \-mold-mnemonics -\&\-mfull-toc \-mminimal-toc \-mno-fp-in-toc \-mno-sum-in-toc -\&\-m64 \-m32 \-mxl-call \-mno-xl-call \-mpe -\&\-msoft-float \-mhard-float \-mmultiple \-mno-multiple -\&\-mstring \-mno-string \-mupdate \-mno-update -\&\-mfused-madd \-mno-fused-madd \-mbit-align \-mno-bit-align -\&\-mstrict-align \-mno-strict-align \-mrelocatable -\&\-mno-relocatable \-mrelocatable-lib \-mno-relocatable-lib -\&\-mtoc \-mno-toc \-mlittle \-mlittle-endian \-mbig \-mbig-endian -\&\-mcall-aix \-mcall-sysv \-mcall-netbsd -\&\-maix-struct-return \-msvr4\-struct-return -\&\-mabi=altivec \-mabi=no-altivec -\&\-mprototype \-mno-prototype -\&\-msim \-mmvme \-mads \-myellowknife \-memb \-msdata -\&\-msdata=\fR\fIopt\fR \fB\-mvxworks \-G\fR \fInum\fR \fB\-pthread\fR -.Sp -\&\fI\s-1RT\s0 Options\fR -.Sp -\&\fB\-mcall-lib-mul \-mfp-arg-in-fpregs \-mfp-arg-in-gregs -\&\-mfull-fp-blocks \-mhc-struct-return \-min-line-mul -\&\-mminimum-fp-blocks \-mnohc-struct-return\fR -.Sp -\&\fI\s-1MIPS\s0 Options\fR -.Sp -\&\fB\-mabicalls \-march=\fR\fIcpu-type\fR \fB\-mtune=\fR\fIcpu=type\fR -\&\fB\-mcpu=\fR\fIcpu-type\fR \fB\-membedded-data \-muninit-const-in-rodata -\&\-membedded-pic \-mfp32 \-mfp64 \-mfused-madd \-mno-fused-madd -\&\-mgas \-mgp32 \-mgp64 -\&\-mgpopt \-mhalf-pic \-mhard-float \-mint64 \-mips1 -\&\-mips2 \-mips3 \-mips4 \-mlong64 \-mlong32 \-mlong-calls \-mmemcpy -\&\-mmips-as \-mmips-tfile \-mno-abicalls -\&\-mno-embedded-data \-mno-uninit-const-in-rodata -\&\-mno-embedded-pic \-mno-gpopt \-mno-long-calls -\&\-mno-memcpy \-mno-mips-tfile \-mno-rnames \-mno-stats -\&\-mrnames \-msoft-float -\&\-m4650 \-msingle-float \-mmad -\&\-mstats \-EL \-EB \-G\fR \fInum\fR \fB\-nocpp -\&\-mabi=32 \-mabi=n32 \-mabi=64 \-mabi=eabi -\&\-mfix7000 \-mno-crt0 \-mflush-func=\fR\fIfunc\fR \fB\-mno-flush-func\fR -.Sp -\&\fIi386 and x86\-64 Options\fR -.Sp -\&\fB\-mcpu=\fR\fIcpu-type\fR \fB\-march=\fR\fIcpu-type\fR \fB\-mfpmath=\fR\fIunit\fR -\&\fB\-masm=\fR\fIdialect\fR \fB\-mno-fancy-math-387 -\&\-mno-fp-ret-in-387 \-msoft-float \-msvr3\-shlib -\&\-mno-wide-multiply \-mrtd \-malign-double -\&\-mpreferred-stack-boundary=\fR\fInum\fR -\&\fB\-mmmx \-msse \-msse2 \-m3dnow -\&\-mthreads \-mno-align-stringops \-minline-all-stringops -\&\-mpush-args \-maccumulate-outgoing-args \-m128bit-long-double -\&\-m96bit-long-double \-mregparm=\fR\fInum\fR \fB\-momit-leaf-frame-pointer -\&\-mno-red-zone -\&\-mcmodel=\fR\fIcode-model\fR -\&\fB\-m32 \-m64\fR -.Sp -\&\fI\s-1HPPA\s0 Options\fR -.Sp -\&\fB\-march=\fR\fIarchitecture-type\fR -\&\fB\-mbig-switch \-mdisable-fpregs \-mdisable-indexing -\&\-mfast-indirect-calls \-mgas \-mjump-in-delay -\&\-mlong-load-store \-mno-big-switch \-mno-disable-fpregs -\&\-mno-disable-indexing \-mno-fast-indirect-calls \-mno-gas -\&\-mno-jump-in-delay \-mno-long-load-store -\&\-mno-portable-runtime \-mno-soft-float -\&\-mno-space-regs \-msoft-float \-mpa-risc-1\-0 -\&\-mpa-risc-1\-1 \-mpa-risc-2\-0 \-mportable-runtime -\&\-mschedule=\fR\fIcpu-type\fR \fB\-mspace-regs\fR -.Sp -\&\fIIntel 960 Options\fR -.Sp -\&\fB\-m\fR\fIcpu-type\fR \fB\-masm-compat \-mclean-linkage -\&\-mcode-align \-mcomplex-addr \-mleaf-procedures -\&\-mic-compat \-mic2.0\-compat \-mic3.0\-compat -\&\-mintel-asm \-mno-clean-linkage \-mno-code-align -\&\-mno-complex-addr \-mno-leaf-procedures -\&\-mno-old-align \-mno-strict-align \-mno-tail-call -\&\-mnumerics \-mold-align \-msoft-float \-mstrict-align -\&\-mtail-call\fR -.Sp -\&\fI\s-1DEC\s0 Alpha Options\fR -.Sp -\&\fB\-mno-fp-regs \-msoft-float \-malpha-as \-mgas -\&\-mieee \-mieee-with-inexact \-mieee-conformant -\&\-mfp-trap-mode=\fR\fImode\fR \fB\-mfp-rounding-mode=\fR\fImode\fR -\&\fB\-mtrap-precision=\fR\fImode\fR \fB\-mbuild-constants -\&\-mcpu=\fR\fIcpu-type\fR \fB\-mtune=\fR\fIcpu-type\fR -\&\fB\-mbwx \-mmax \-mfix \-mcix -\&\-mfloat-vax \-mfloat-ieee -\&\-mexplicit-relocs \-msmall-data \-mlarge-data -\&\-mmemory-latency=\fR\fItime\fR -.Sp -\&\fI\s-1DEC\s0 Alpha/VMS Options\fR -.Sp -\&\fB\-mvms-return-codes\fR -.Sp -\&\fIClipper Options\fR -.Sp -\&\fB\-mc300 \-mc400\fR -.Sp -\&\fIH8/300 Options\fR -.Sp -\&\fB\-mrelax \-mh \-ms \-mint32 \-malign-300\fR -.Sp -\&\fI\s-1SH\s0 Options\fR -.Sp -\&\fB\-m1 \-m2 \-m3 \-m3e -\&\-m4\-nofpu \-m4\-single-only \-m4\-single \-m4 -\&\-m5\-64media \-m5\-64media-nofpu -\&\-m5\-32media \-m5\-32media-nofpu -\&\-m5\-compact \-m5\-compact-nofpu -\&\-mb \-ml \-mdalign \-mrelax -\&\-mbigtable \-mfmovd \-mhitachi \-mnomacsave -\&\-mieee \-misize \-mpadstruct \-mspace -\&\-mprefergot \-musermode\fR -.Sp -\&\fISystem V Options\fR -.Sp -\&\fB\-Qy \-Qn \-YP,\fR\fIpaths\fR \fB\-Ym,\fR\fIdir\fR -.Sp -\&\fI\s-1ARC\s0 Options\fR -.Sp -\&\fB\-EB \-EL -\&\-mmangle-cpu \-mcpu=\fR\fIcpu\fR \fB\-mtext=\fR\fItext-section\fR -\&\fB\-mdata=\fR\fIdata-section\fR \fB\-mrodata=\fR\fIreadonly-data-section\fR -.Sp -\&\fITMS320C3x/C4x Options\fR -.Sp -\&\fB\-mcpu=\fR\fIcpu\fR \fB\-mbig \-msmall \-mregparm \-mmemparm -\&\-mfast-fix \-mmpyi \-mbk \-mti \-mdp-isr-reload -\&\-mrpts=\fR\fIcount\fR \fB\-mrptb \-mdb \-mloop-unsigned -\&\-mparallel-insns \-mparallel-mpy \-mpreserve-float\fR -.Sp -\&\fIV850 Options\fR -.Sp -\&\fB\-mlong-calls \-mno-long-calls \-mep \-mno-ep -\&\-mprolog-function \-mno-prolog-function \-mspace -\&\-mtda=\fR\fIn\fR \fB\-msda=\fR\fIn\fR \fB\-mzda=\fR\fIn\fR -\&\fB\-mv850 \-mbig-switch\fR -.Sp -\&\fI\s-1NS32K\s0 Options\fR -.Sp -\&\fB\-m32032 \-m32332 \-m32532 \-m32081 \-m32381 -\&\-mmult-add \-mnomult-add \-msoft-float \-mrtd \-mnortd -\&\-mregparam \-mnoregparam \-msb \-mnosb -\&\-mbitfield \-mnobitfield \-mhimem \-mnohimem\fR -.Sp -\&\fI\s-1AVR\s0 Options\fR -.Sp -\&\fB\-mmcu=\fR\fImcu\fR \fB\-msize \-minit-stack=\fR\fIn\fR \fB\-mno-interrupts -\&\-mcall-prologues \-mno-tablejump \-mtiny-stack\fR -.Sp -\&\fIMCore Options\fR -.Sp -\&\fB\-mhardlit \-mno-hardlit \-mdiv \-mno-div \-mrelax-immediates -\&\-mno-relax-immediates \-mwide-bitfields \-mno-wide-bitfields -\&\-m4byte-functions \-mno-4byte-functions \-mcallgraph-data -\&\-mno-callgraph-data \-mslow-bytes \-mno-slow-bytes \-mno-lsim -\&\-mlittle-endian \-mbig-endian \-m210 \-m340 \-mstack-increment\fR -.Sp -\&\fI\s-1MMIX\s0 Options\fR -.Sp -\&\fB\-mlibfuncs \-mno-libfuncs \-mepsilon \-mno-epsilon \-mabi=gnu -\&\-mabi=mmixware \-mzero-extend \-mknuthdiv \-mtoplevel-symbols -\&\-melf \-mbranch-predict \-mno-branch-predict \-mbase-addresses -\&\-mno-base-addresses\fR -.Sp -\&\fI\s-1IA-64\s0 Options\fR -.Sp -\&\fB\-mbig-endian \-mlittle-endian \-mgnu-as \-mgnu-ld \-mno-pic -\&\-mvolatile-asm-stop \-mb-step \-mregister-names \-mno-sdata -\&\-mconstant-gp \-mauto-pic \-minline-divide-min-latency -\&\-minline-divide-max-throughput \-mno-dwarf2\-asm -\&\-mfixed-range=\fR\fIregister-range\fR -.Sp -\&\fID30V Options\fR -.Sp -\&\fB\-mextmem \-mextmemory \-monchip \-mno-asm-optimize -\&\-masm-optimize \-mbranch-cost=\fR\fIn\fR \fB\-mcond-exec=\fR\fIn\fR -.Sp -\&\fIS/390 and zSeries Options\fR -.Sp -\&\fB\-mhard-float \-msoft-float \-mbackchain \-mno-backchain -\&\-msmall-exec \-mno-small-exec \-mmvcle \-mno-mvcle -\&\-m64 \-m31 \-mdebug \-mno-debug\fR -.Sp -\&\fI\s-1CRIS\s0 Options\fR -.Sp -\&\fB\-mcpu=\fR\fIcpu\fR \fB\-march=\fR\fIcpu\fR \fB\-mtune=\fR\fIcpu\fR -\&\fB\-mmax-stack-frame=\fR\fIn\fR \fB\-melinux-stacksize=\fR\fIn\fR -\&\fB\-metrax4 \-metrax100 \-mpdebug \-mcc-init \-mno-side-effects -\&\-mstack-align \-mdata-align \-mconst-align -\&\-m32\-bit \-m16\-bit \-m8\-bit \-mno-prologue-epilogue \-mno-gotplt -\&\-melf \-maout \-melinux \-mlinux \-sim \-sim2\fR -.Sp -\&\fI\s-1PDP-11\s0 Options\fR -.Sp -\&\fB\-mfpu \-msoft-float \-mac0 \-mno-ac0 \-m40 \-m45 \-m10 -\&\-mbcopy \-mbcopy-builtin \-mint32 \-mno-int16 -\&\-mint16 \-mno-int32 \-mfloat32 \-mno-float64 -\&\-mfloat64 \-mno-float32 \-mabshi \-mno-abshi -\&\-mbranch-expensive \-mbranch-cheap -\&\-msplit \-mno-split \-munix-asm \-mdec-asm\fR -.Sp -\&\fIXstormy16 Options\fR -.Sp -\&\fB\-msim\fR -.Sp -\&\fIXtensa Options\fR -.Sp -\&\fB\-mbig-endian \-mlittle-endian -\&\-mdensity \-mno-density -\&\-mmac16 \-mno-mac16 -\&\-mmul16 \-mno-mul16 -\&\-mmul32 \-mno-mul32 -\&\-mnsa \-mno-nsa -\&\-mminmax \-mno-minmax -\&\-msext \-mno-sext -\&\-mbooleans \-mno-booleans -\&\-mhard-float \-msoft-float -\&\-mfused-madd \-mno-fused-madd -\&\-mserialize-volatile \-mno-serialize-volatile -\&\-mtext-section-literals \-mno-text-section-literals -\&\-mtarget-align \-mno-target-align -\&\-mlongcalls \-mno-longcalls\fR -.Ip "\fICode Generation Options\fR" 4 -.IX Item "Code Generation Options" -\&\fB\-fcall-saved-\fR\fIreg\fR \fB\-fcall-used-\fR\fIreg\fR -\&\fB\-ffixed-\fR\fIreg\fR \fB\-fexceptions -\&\-fnon-call-exceptions \-funwind-tables -\&\-fasynchronous-unwind-tables -\&\-finhibit-size-directive \-finstrument-functions -\&\-fno-common \-fno-ident \-fno-gnu-linker -\&\-fpcc-struct-return \-fpic \-fPIC -\&\-freg-struct-return \-fshared-data \-fshort-enums -\&\-fshort-double \-fshort-wchar \-fvolatile -\&\-fvolatile-global \-fvolatile-static -\&\-fverbose-asm \-fpack-struct \-fstack-check -\&\-fstack-limit-register=\fR\fIreg\fR \fB\-fstack-limit-symbol=\fR\fIsym\fR -\&\fB\-fargument-alias \-fargument-noalias -\&\-fargument-noalias-global \-fleading-underscore\fR -.Sh "Options Controlling the Kind of Output" -.IX Subsection "Options Controlling the Kind of Output" -Compilation can involve up to four stages: preprocessing, compilation -proper, assembly and linking, always in that order. The first three -stages apply to an individual source file, and end by producing an -object file; linking combines all the object files (those newly -compiled, and those specified as input) into an executable file. -.PP -For any given input file, the file name suffix determines what kind of -compilation is done: -.Ip "\fIfile\fR\fB.c\fR" 4 -.IX Item "file.c" -C source code which must be preprocessed. -.Ip "\fIfile\fR\fB.i\fR" 4 -.IX Item "file.i" -C source code which should not be preprocessed. -.Ip "\fIfile\fR\fB.ii\fR" 4 -.IX Item "file.ii" -\&\*(C+ source code which should not be preprocessed. -.Ip "\fIfile\fR\fB.m\fR" 4 -.IX Item "file.m" -Objective-C source code. Note that you must link with the library -\&\fIlibobjc.a\fR to make an Objective-C program work. -.Ip "\fIfile\fR\fB.mi\fR" 4 -.IX Item "file.mi" -Objective-C source code which should not be preprocessed. -.Ip "\fIfile\fR\fB.h\fR" 4 -.IX Item "file.h" -C header file (not to be compiled or linked). -.Ip "\fIfile\fR\fB.cc\fR" 4 -.IX Item "file.cc" -.PD 0 -.Ip "\fIfile\fR\fB.cp\fR" 4 -.IX Item "file.cp" -.Ip "\fIfile\fR\fB.cxx\fR" 4 -.IX Item "file.cxx" -.Ip "\fIfile\fR\fB.cpp\fR" 4 -.IX Item "file.cpp" -.Ip "\fIfile\fR\fB.c++\fR" 4 -.IX Item "file.c++" -.Ip "\fIfile\fR\fB.C\fR" 4 -.IX Item "file.C" -.PD -\&\*(C+ source code which must be preprocessed. Note that in \fB.cxx\fR, -the last two letters must both be literally \fBx\fR. Likewise, -\&\fB.C\fR refers to a literal capital C. -.Ip "\fIfile\fR\fB.f\fR" 4 -.IX Item "file.f" -.PD 0 -.Ip "\fIfile\fR\fB.for\fR" 4 -.IX Item "file.for" -.Ip "\fIfile\fR\fB.FOR\fR" 4 -.IX Item "file.FOR" -.PD -Fortran source code which should not be preprocessed. -.Ip "\fIfile\fR\fB.F\fR" 4 -.IX Item "file.F" -.PD 0 -.Ip "\fIfile\fR\fB.fpp\fR" 4 -.IX Item "file.fpp" -.Ip "\fIfile\fR\fB.FPP\fR" 4 -.IX Item "file.FPP" -.PD -Fortran source code which must be preprocessed (with the traditional -preprocessor). -.Ip "\fIfile\fR\fB.r\fR" 4 -.IX Item "file.r" -Fortran source code which must be preprocessed with a \s-1RATFOR\s0 -preprocessor (not included with \s-1GCC\s0). -.Ip "\fIfile\fR\fB.ads\fR" 4 -.IX Item "file.ads" -Ada source code file which contains a library unit declaration (a -declaration of a package, subprogram, or generic, or a generic -instantiation), or a library unit renaming declaration (a package, -generic, or subprogram renaming declaration). Such files are also -called \fIspecs\fR. -.Ip "\fIfile\fR\fB.adb\fR" 4 -.IX Item "file.adb" -Ada source code file containing a library unit body (a subprogram or -package body). Such files are also called \fIbodies\fR. -.Ip "\fIfile\fR\fB.s\fR" 4 -.IX Item "file.s" -Assembler code. -.Ip "\fIfile\fR\fB.S\fR" 4 -.IX Item "file.S" -Assembler code which must be preprocessed. -.Ip "\fIother\fR" 4 -.IX Item "other" -An object file to be fed straight into linking. -Any file name with no recognized suffix is treated this way. -.PP -You can specify the input language explicitly with the \fB\-x\fR option: -.Ip "\fB\-x\fR \fIlanguage\fR" 4 -.IX Item "-x language" -Specify explicitly the \fIlanguage\fR for the following input files -(rather than letting the compiler choose a default based on the file -name suffix). This option applies to all following input files until -the next \fB\-x\fR option. Possible values for \fIlanguage\fR are: -.Sp -.Vb 7 -\& c c-header cpp-output -\& c++ c++-cpp-output -\& objective-c objc-cpp-output -\& assembler assembler-with-cpp -\& ada -\& f77 f77-cpp-input ratfor -\& java -.Ve -.Ip "\fB\-x none\fR" 4 -.IX Item "-x none" -Turn off any specification of a language, so that subsequent files are -handled according to their file name suffixes (as they are if \fB\-x\fR -has not been used at all). -.Ip "\fB\-pass-exit-codes\fR" 4 -.IX Item "-pass-exit-codes" -Normally the \fBgcc\fR program will exit with the code of 1 if any -phase of the compiler returns a non-success return code. If you specify -\&\fB\-pass-exit-codes\fR, the \fBgcc\fR program will instead return with -numerically highest error produced by any phase that returned an error -indication. -.PP -If you only want some of the stages of compilation, you can use -\&\fB\-x\fR (or filename suffixes) to tell \fBgcc\fR where to start, and -one of the options \fB\-c\fR, \fB\-S\fR, or \fB\-E\fR to say where -\&\fBgcc\fR is to stop. Note that some combinations (for example, -\&\fB\-x cpp-output \-E\fR) instruct \fBgcc\fR to do nothing at all. -.Ip "\fB\-c\fR" 4 -.IX Item "-c" -Compile or assemble the source files, but do not link. The linking -stage simply is not done. The ultimate output is in the form of an -object file for each source file. -.Sp -By default, the object file name for a source file is made by replacing -the suffix \fB.c\fR, \fB.i\fR, \fB.s\fR, etc., with \fB.o\fR. -.Sp -Unrecognized input files, not requiring compilation or assembly, are -ignored. -.Ip "\fB\-S\fR" 4 -.IX Item "-S" -Stop after the stage of compilation proper; do not assemble. The output -is in the form of an assembler code file for each non-assembler input -file specified. -.Sp -By default, the assembler file name for a source file is made by -replacing the suffix \fB.c\fR, \fB.i\fR, etc., with \fB.s\fR. -.Sp -Input files that don't require compilation are ignored. -.Ip "\fB\-E\fR" 4 -.IX Item "-E" -Stop after the preprocessing stage; do not run the compiler proper. The -output is in the form of preprocessed source code, which is sent to the -standard output. -.Sp -Input files which don't require preprocessing are ignored. -.Ip "\fB\-o\fR \fIfile\fR" 4 -.IX Item "-o file" -Place output in file \fIfile\fR. This applies regardless to whatever -sort of output is being produced, whether it be an executable file, -an object file, an assembler file or preprocessed C code. -.Sp -Since only one output file can be specified, it does not make sense to -use \fB\-o\fR when compiling more than one input file, unless you are -producing an executable file as output. -.Sp -If \fB\-o\fR is not specified, the default is to put an executable file -in \fIa.out\fR, the object file for \fI\fIsource\fI.\fIsuffix\fI\fR in -\&\fI\fIsource\fI.o\fR, its assembler file in \fI\fIsource\fI.s\fR, and -all preprocessed C source on standard output. -.Ip "\fB\-v\fR" 4 -.IX Item "-v" -Print (on standard error output) the commands executed to run the stages -of compilation. Also print the version number of the compiler driver -program and of the preprocessor and the compiler proper. -.Ip "\fB\-###\fR" 4 -.IX Item "-###" -Like \fB\-v\fR except the commands are not executed and all command -arguments are quoted. This is useful for shell scripts to capture the -driver-generated command lines. -.Ip "\fB\-pipe\fR" 4 -.IX Item "-pipe" -Use pipes rather than temporary files for communication between the -various stages of compilation. This fails to work on some systems where -the assembler is unable to read from a pipe; but the \s-1GNU\s0 assembler has -no trouble. -.Ip "\fB\*(--help\fR" 4 -.IX Item "help" -Print (on the standard output) a description of the command line options -understood by \fBgcc\fR. If the \fB\-v\fR option is also specified -then \fB\*(--help\fR will also be passed on to the various processes -invoked by \fBgcc\fR, so that they can display the command line options -they accept. If the \fB\-W\fR option is also specified then command -line options which have no documentation associated with them will also -be displayed. -.Ip "\fB\*(--target-help\fR" 4 -.IX Item "target-help" -Print (on the standard output) a description of target specific command -line options for each tool. -.Ip "\fB\*(--version\fR" 4 -.IX Item "version" -Display the version number and copyrights of the invoked \s-1GCC\s0. -.Sh "Compiling \*(C+ Programs" -.IX Subsection "Compiling Programs" -\&\*(C+ source files conventionally use one of the suffixes \fB.C\fR, -\&\fB.cc\fR, \fB.cpp\fR, \fB.c++\fR, \fB.cp\fR, or \fB.cxx\fR; -preprocessed \*(C+ files use the suffix \fB.ii\fR. \s-1GCC\s0 recognizes -files with these names and compiles them as \*(C+ programs even if you -call the compiler the same way as for compiling C programs (usually with -the name \fBgcc\fR). -.PP -However, \*(C+ programs often require class libraries as well as a -compiler that understands the \*(C+ language\-\-\-and under some -circumstances, you might want to compile programs from standard input, -or otherwise without a suffix that flags them as \*(C+ programs. -\&\fBg++\fR is a program that calls \s-1GCC\s0 with the default language -set to \*(C+, and automatically specifies linking against the \*(C+ -library. On many systems, \fBg++\fR is also -installed with the name \fBc++\fR. -.PP -When you compile \*(C+ programs, you may specify many of the same -command-line options that you use for compiling programs in any -language; or command-line options meaningful for C and related -languages; or options that are meaningful only for \*(C+ programs. -.Sh "Options Controlling C Dialect" -.IX Subsection "Options Controlling C Dialect" -The following options control the dialect of C (or languages derived -from C, such as \*(C+ and Objective-C) that the compiler accepts: -.Ip "\fB\-ansi\fR" 4 -.IX Item "-ansi" -In C mode, support all \s-1ISO\s0 C89 programs. In \*(C+ mode, -remove \s-1GNU\s0 extensions that conflict with \s-1ISO\s0 \*(C+. -.Sp -This turns off certain features of \s-1GCC\s0 that are incompatible with \s-1ISO\s0 -C89 (when compiling C code), or of standard \*(C+ (when compiling \*(C+ code), -such as the \f(CW\*(C`asm\*(C'\fR and \f(CW\*(C`typeof\*(C'\fR keywords, and -predefined macros such as \f(CW\*(C`unix\*(C'\fR and \f(CW\*(C`vax\*(C'\fR that identify the -type of system you are using. It also enables the undesirable and -rarely used \s-1ISO\s0 trigraph feature. For the C compiler, -it disables recognition of \*(C+ style \fB//\fR comments as well as -the \f(CW\*(C`inline\*(C'\fR keyword. -.Sp -The alternate keywords \f(CW\*(C`_\|_asm_\|_\*(C'\fR, \f(CW\*(C`_\|_extension_\|_\*(C'\fR, -\&\f(CW\*(C`_\|_inline_\|_\*(C'\fR and \f(CW\*(C`_\|_typeof_\|_\*(C'\fR continue to work despite -\&\fB\-ansi\fR. You would not want to use them in an \s-1ISO\s0 C program, of -course, but it is useful to put them in header files that might be included -in compilations done with \fB\-ansi\fR. Alternate predefined macros -such as \f(CW\*(C`_\|_unix_\|_\*(C'\fR and \f(CW\*(C`_\|_vax_\|_\*(C'\fR are also available, with or -without \fB\-ansi\fR. -.Sp -The \fB\-ansi\fR option does not cause non-ISO programs to be -rejected gratuitously. For that, \fB\-pedantic\fR is required in -addition to \fB\-ansi\fR. -.Sp -The macro \f(CW\*(C`_\|_STRICT_ANSI_\|_\*(C'\fR is predefined when the \fB\-ansi\fR -option is used. Some header files may notice this macro and refrain -from declaring certain functions or defining certain macros that the -\&\s-1ISO\s0 standard doesn't call for; this is to avoid interfering with any -programs that might use these names for other things. -.Sp -Functions which would normally be built in but do not have semantics -defined by \s-1ISO\s0 C (such as \f(CW\*(C`alloca\*(C'\fR and \f(CW\*(C`ffs\*(C'\fR) are not built-in -functions with \fB\-ansi\fR is used. -.Ip "\fB\-std=\fR" 4 -.IX Item "-std=" -Determine the language standard. This option is currently only -supported when compiling C. A value for this option must be provided; -possible values are -.RS 4 -.Ip "\fBc89\fR" 4 -.IX Item "c89" -.PD 0 -.Ip "\fBiso9899:1990\fR" 4 -.IX Item "iso9899:1990" -.PD -\&\s-1ISO\s0 C89 (same as \fB\-ansi\fR). -.Ip "\fBiso9899:199409\fR" 4 -.IX Item "iso9899:199409" -\&\s-1ISO\s0 C89 as modified in amendment 1. -.Ip "\fBc99\fR" 4 -.IX Item "c99" -.PD 0 -.Ip "\fBc9x\fR" 4 -.IX Item "c9x" -.Ip "\fBiso9899:1999\fR" 4 -.IX Item "iso9899:1999" -.Ip "\fBiso9899:199x\fR" 4 -.IX Item "iso9899:199x" -.PD -\&\s-1ISO\s0 C99. Note that this standard is not yet fully supported; see -<\fBhttp://gcc.gnu.org/gcc-3.1/c99status.html\fR> for more information. The -names \fBc9x\fR and \fBiso9899:199x\fR are deprecated. -.Ip "\fBgnu89\fR" 4 -.IX Item "gnu89" -Default, \s-1ISO\s0 C89 plus \s-1GNU\s0 extensions (including some C99 features). -.Ip "\fBgnu99\fR" 4 -.IX Item "gnu99" -.PD 0 -.Ip "\fBgnu9x\fR" 4 -.IX Item "gnu9x" -.PD -\&\s-1ISO\s0 C99 plus \s-1GNU\s0 extensions. When \s-1ISO\s0 C99 is fully implemented in \s-1GCC\s0, -this will become the default. The name \fBgnu9x\fR is deprecated. -.RE -.RS 4 -.Sp -Even when this option is not specified, you can still use some of the -features of newer standards in so far as they do not conflict with -previous C standards. For example, you may use \f(CW\*(C`_\|_restrict_\|_\*(C'\fR even -when \fB\-std=c99\fR is not specified. -.Sp -The \fB\-std\fR options specifying some version of \s-1ISO\s0 C have the same -effects as \fB\-ansi\fR, except that features that were not in \s-1ISO\s0 C89 -but are in the specified version (for example, \fB//\fR comments and -the \f(CW\*(C`inline\*(C'\fR keyword in \s-1ISO\s0 C99) are not disabled. -.RE -.Ip "\fB\-aux-info\fR \fIfilename\fR" 4 -.IX Item "-aux-info filename" -Output to the given filename prototyped declarations for all functions -declared and/or defined in a translation unit, including those in header -files. This option is silently ignored in any language other than C. -.Sp -Besides declarations, the file indicates, in comments, the origin of -each declaration (source file and line), whether the declaration was -implicit, prototyped or unprototyped (\fBI\fR, \fBN\fR for new or -\&\fBO\fR for old, respectively, in the first character after the line -number and the colon), and whether it came from a declaration or a -definition (\fBC\fR or \fBF\fR, respectively, in the following -character). In the case of function definitions, a K&R-style list of -arguments followed by their declarations is also provided, inside -comments, after the declaration. -.Ip "\fB\-fno-asm\fR" 4 -.IX Item "-fno-asm" -Do not recognize \f(CW\*(C`asm\*(C'\fR, \f(CW\*(C`inline\*(C'\fR or \f(CW\*(C`typeof\*(C'\fR as a -keyword, so that code can use these words as identifiers. You can use -the keywords \f(CW\*(C`_\|_asm_\|_\*(C'\fR, \f(CW\*(C`_\|_inline_\|_\*(C'\fR and \f(CW\*(C`_\|_typeof_\|_\*(C'\fR -instead. \fB\-ansi\fR implies \fB\-fno-asm\fR. -.Sp -In \*(C+, this switch only affects the \f(CW\*(C`typeof\*(C'\fR keyword, since -\&\f(CW\*(C`asm\*(C'\fR and \f(CW\*(C`inline\*(C'\fR are standard keywords. You may want to -use the \fB\-fno-gnu-keywords\fR flag instead, which has the same -effect. In C99 mode (\fB\-std=c99\fR or \fB\-std=gnu99\fR), this -switch only affects the \f(CW\*(C`asm\*(C'\fR and \f(CW\*(C`typeof\*(C'\fR keywords, since -\&\f(CW\*(C`inline\*(C'\fR is a standard keyword in \s-1ISO\s0 C99. -.Ip "\fB\-fno-builtin\fR" 4 -.IX Item "-fno-builtin" -.PD 0 -.Ip "\fB\-fno-builtin-\fR\fIfunction\fR\fB \fR(C and Objective-C only)" 4 -.IX Item "-fno-builtin-function (C and Objective-C only)" -.PD -Don't recognize built-in functions that do not begin with -\&\fB_\|_builtin_\fR as prefix. -.Sp -\&\s-1GCC\s0 normally generates special code to handle certain built-in functions -more efficiently; for instance, calls to \f(CW\*(C`alloca\*(C'\fR may become single -instructions that adjust the stack directly, and calls to \f(CW\*(C`memcpy\*(C'\fR -may become inline copy loops. The resulting code is often both smaller -and faster, but since the function calls no longer appear as such, you -cannot set a breakpoint on those calls, nor can you change the behavior -of the functions by linking with a different library. -.Sp -In \*(C+, \fB\-fno-builtin\fR is always in effect. The \fB\-fbuiltin\fR -option has no effect. Therefore, in \*(C+, the only way to get the -optimization benefits of built-in functions is to call the function -using the \fB_\|_builtin_\fR prefix. The \s-1GNU\s0 \*(C+ Standard Library uses -built-in functions to implement many functions (like -\&\f(CW\*(C`std::strchr\*(C'\fR), so that you automatically get efficient code. -.Sp -With the \fB\-fno-builtin-\fR\fIfunction\fR option, not available -when compiling \*(C+, only the built-in function \fIfunction\fR is -disabled. \fIfunction\fR must not begin with \fB_\|_builtin_\fR. If a -function is named this is not built-in in this version of \s-1GCC\s0, this -option is ignored. There is no corresponding -\&\fB\-fbuiltin-\fR\fIfunction\fR option; if you wish to enable -built-in functions selectively when using \fB\-fno-builtin\fR or -\&\fB\-ffreestanding\fR, you may define macros such as: -.Sp -.Vb 2 -\& #define abs(n) __builtin_abs ((n)) -\& #define strcpy(d, s) __builtin_strcpy ((d), (s)) -.Ve -.Ip "\fB\-fhosted\fR" 4 -.IX Item "-fhosted" -Assert that compilation takes place in a hosted environment. This implies -\&\fB\-fbuiltin\fR. A hosted environment is one in which the -entire standard library is available, and in which \f(CW\*(C`main\*(C'\fR has a return -type of \f(CW\*(C`int\*(C'\fR. Examples are nearly everything except a kernel. -This is equivalent to \fB\-fno-freestanding\fR. -.Ip "\fB\-ffreestanding\fR" 4 -.IX Item "-ffreestanding" -Assert that compilation takes place in a freestanding environment. This -implies \fB\-fno-builtin\fR. A freestanding environment -is one in which the standard library may not exist, and program startup may -not necessarily be at \f(CW\*(C`main\*(C'\fR. The most obvious example is an \s-1OS\s0 kernel. -This is equivalent to \fB\-fno-hosted\fR. -.Ip "\fB\-trigraphs\fR" 4 -.IX Item "-trigraphs" -Support \s-1ISO\s0 C trigraphs. The \fB\-ansi\fR option (and \fB\-std\fR -options for strict \s-1ISO\s0 C conformance) implies \fB\-trigraphs\fR. -.Ip "\fB\-no-integrated-cpp\fR" 4 -.IX Item "-no-integrated-cpp" -Invoke the external cpp during compilation. The default is to use the -integrated cpp (internal cpp). This option also allows a -user-supplied cpp via the \fB\-B\fR option. This flag is applicable -in both C and \*(C+ modes. -.Sp -We do not guarantee to retain this option in future, and we may change -its semantics. -.Ip "\fB\-traditional\fR" 4 -.IX Item "-traditional" -Attempt to support some aspects of traditional C compilers. -Specifically: -.RS 4 -.Ip "\(bu" 4 -All \f(CW\*(C`extern\*(C'\fR declarations take effect globally even if they -are written inside of a function definition. This includes implicit -declarations of functions. -.Ip "\(bu" 4 -The newer keywords \f(CW\*(C`typeof\*(C'\fR, \f(CW\*(C`inline\*(C'\fR, \f(CW\*(C`signed\*(C'\fR, \f(CW\*(C`const\*(C'\fR -and \f(CW\*(C`volatile\*(C'\fR are not recognized. (You can still use the -alternative keywords such as \f(CW\*(C`_\|_typeof_\|_\*(C'\fR, \f(CW\*(C`_\|_inline_\|_\*(C'\fR, and -so on.) -.Ip "\(bu" 4 -Comparisons between pointers and integers are always allowed. -.Ip "\(bu" 4 -Integer types \f(CW\*(C`unsigned short\*(C'\fR and \f(CW\*(C`unsigned char\*(C'\fR promote -to \f(CW\*(C`unsigned int\*(C'\fR. -.Ip "\(bu" 4 -Out-of-range floating point literals are not an error. -.Ip "\(bu" 4 -Certain constructs which \s-1ISO\s0 regards as a single invalid preprocessing -number, such as \fB0xe-0xd\fR, are treated as expressions instead. -.Ip "\(bu" 4 -String ``constants'' are not necessarily constant; they are stored in -writable space, and identical looking constants are allocated -separately. (This is the same as the effect of -\&\fB\-fwritable-strings\fR.) -.Ip "\(bu" 4 -All automatic variables not declared \f(CW\*(C`register\*(C'\fR are preserved by -\&\f(CW\*(C`longjmp\*(C'\fR. Ordinarily, \s-1GNU\s0 C follows \s-1ISO\s0 C: automatic variables -not declared \f(CW\*(C`volatile\*(C'\fR may be clobbered. -.Ip "\(bu" 4 -The character escape sequences \fB\ex\fR and \fB\ea\fR evaluate as the -literal characters \fBx\fR and \fBa\fR respectively. Without -\&\fB\-traditional\fR, \fB\ex\fR is a prefix for the hexadecimal -representation of a character, and \fB\ea\fR produces a bell. -.RE -.RS 4 -.Sp -This option is deprecated and may be removed. -.Sp -You may wish to use \fB\-fno-builtin\fR as well as \fB\-traditional\fR -if your program uses names that are normally \s-1GNU\s0 C built-in functions for -other purposes of its own. -.Sp -You cannot use \fB\-traditional\fR if you include any header files that -rely on \s-1ISO\s0 C features. Some vendors are starting to ship systems with -\&\s-1ISO\s0 C header files and you cannot use \fB\-traditional\fR on such -systems to compile files that include any system headers. -.Sp -The \fB\-traditional\fR option also enables \fB\-traditional-cpp\fR. -.RE -.Ip "\fB\-traditional-cpp\fR" 4 -.IX Item "-traditional-cpp" -Attempt to support some aspects of traditional C preprocessors. -See the \s-1GNU\s0 \s-1CPP\s0 manual for details. -.Ip "\fB\-fcond-mismatch\fR" 4 -.IX Item "-fcond-mismatch" -Allow conditional expressions with mismatched types in the second and -third arguments. The value of such an expression is void. This option -is not supported for \*(C+. -.Ip "\fB\-funsigned-char\fR" 4 -.IX Item "-funsigned-char" -Let the type \f(CW\*(C`char\*(C'\fR be unsigned, like \f(CW\*(C`unsigned char\*(C'\fR. -.Sp -Each kind of machine has a default for what \f(CW\*(C`char\*(C'\fR should -be. It is either like \f(CW\*(C`unsigned char\*(C'\fR by default or like -\&\f(CW\*(C`signed char\*(C'\fR by default. -.Sp -Ideally, a portable program should always use \f(CW\*(C`signed char\*(C'\fR or -\&\f(CW\*(C`unsigned char\*(C'\fR when it depends on the signedness of an object. -But many programs have been written to use plain \f(CW\*(C`char\*(C'\fR and -expect it to be signed, or expect it to be unsigned, depending on the -machines they were written for. This option, and its inverse, let you -make such a program work with the opposite default. -.Sp -The type \f(CW\*(C`char\*(C'\fR is always a distinct type from each of -\&\f(CW\*(C`signed char\*(C'\fR or \f(CW\*(C`unsigned char\*(C'\fR, even though its behavior -is always just like one of those two. -.Ip "\fB\-fsigned-char\fR" 4 -.IX Item "-fsigned-char" -Let the type \f(CW\*(C`char\*(C'\fR be signed, like \f(CW\*(C`signed char\*(C'\fR. -.Sp -Note that this is equivalent to \fB\-fno-unsigned-char\fR, which is -the negative form of \fB\-funsigned-char\fR. Likewise, the option -\&\fB\-fno-signed-char\fR is equivalent to \fB\-funsigned-char\fR. -.Ip "\fB\-fsigned-bitfields\fR" 4 -.IX Item "-fsigned-bitfields" -.PD 0 -.Ip "\fB\-funsigned-bitfields\fR" 4 -.IX Item "-funsigned-bitfields" -.Ip "\fB\-fno-signed-bitfields\fR" 4 -.IX Item "-fno-signed-bitfields" -.Ip "\fB\-fno-unsigned-bitfields\fR" 4 -.IX Item "-fno-unsigned-bitfields" -.PD -These options control whether a bit-field is signed or unsigned, when the -declaration does not use either \f(CW\*(C`signed\*(C'\fR or \f(CW\*(C`unsigned\*(C'\fR. By -default, such a bit-field is signed, because this is consistent: the -basic integer types such as \f(CW\*(C`int\*(C'\fR are signed types. -.Sp -However, when \fB\-traditional\fR is used, bit-fields are all unsigned -no matter what. -.Ip "\fB\-fwritable-strings\fR" 4 -.IX Item "-fwritable-strings" -Store string constants in the writable data segment and don't uniquize -them. This is for compatibility with old programs which assume they can -write into string constants. The option \fB\-traditional\fR also has -this effect. -.Sp -Writing into string constants is a very bad idea; ``constants'' should -be constant. -.Ip "\fB\-fallow-single-precision\fR" 4 -.IX Item "-fallow-single-precision" -Do not promote single precision math operations to double precision, -even when compiling with \fB\-traditional\fR. -.Sp -Traditional K&R C promotes all floating point operations to double -precision, regardless of the sizes of the operands. On the -architecture for which you are compiling, single precision may be faster -than double precision. If you must use \fB\-traditional\fR, but want -to use single precision operations when the operands are single -precision, use this option. This option has no effect when compiling -with \s-1ISO\s0 or \s-1GNU\s0 C conventions (the default). -.Sh "Options Controlling \*(C+ Dialect" -.IX Subsection "Options Controlling Dialect" -This section describes the command-line options that are only meaningful -for \*(C+ programs; but you can also use most of the \s-1GNU\s0 compiler options -regardless of what language your program is in. For example, you -might compile a file \f(CW\*(C`firstClass.C\*(C'\fR like this: -.PP -.Vb 1 -\& g++ -g -frepo -O -c firstClass.C -.Ve -In this example, only \fB\-frepo\fR is an option meant -only for \*(C+ programs; you can use the other options with any -language supported by \s-1GCC\s0. -.PP -Here is a list of options that are \fIonly\fR for compiling \*(C+ programs: -.Ip "\fB\-fno-access-control\fR" 4 -.IX Item "-fno-access-control" -Turn off all access checking. This switch is mainly useful for working -around bugs in the access control code. -.Ip "\fB\-fcheck-new\fR" 4 -.IX Item "-fcheck-new" -Check that the pointer returned by \f(CW\*(C`operator new\*(C'\fR is non-null -before attempting to modify the storage allocated. The current Working -Paper requires that \f(CW\*(C`operator new\*(C'\fR never return a null pointer, so -this check is normally unnecessary. -.Sp -An alternative to using this option is to specify that your -\&\f(CW\*(C`operator new\*(C'\fR does not throw any exceptions; if you declare it -\&\fB\f(BIthrow()\fB\fR, G++ will check the return value. See also \fBnew -(nothrow)\fR. -.Ip "\fB\-fconserve-space\fR" 4 -.IX Item "-fconserve-space" -Put uninitialized or runtime-initialized global variables into the -common segment, as C does. This saves space in the executable at the -cost of not diagnosing duplicate definitions. If you compile with this -flag and your program mysteriously crashes after \f(CW\*(C`main()\*(C'\fR has -completed, you may have an object that is being destroyed twice because -two definitions were merged. -.Sp -This option is no longer useful on most targets, now that support has -been added for putting variables into \s-1BSS\s0 without making them common. -.Ip "\fB\-fno-const-strings\fR" 4 -.IX Item "-fno-const-strings" -Give string constants type \f(CW\*(C`char *\*(C'\fR instead of type \f(CW\*(C`const -char *\*(C'\fR. By default, G++ uses type \f(CW\*(C`const char *\*(C'\fR as required by -the standard. Even if you use \fB\-fno-const-strings\fR, you cannot -actually modify the value of a string constant, unless you also use -\&\fB\-fwritable-strings\fR. -.Sp -This option might be removed in a future release of G++. For maximum -portability, you should structure your code so that it works with -string constants that have type \f(CW\*(C`const char *\*(C'\fR. -.Ip "\fB\-fdollars-in-identifiers\fR" 4 -.IX Item "-fdollars-in-identifiers" -Accept \fB$\fR in identifiers. You can also explicitly prohibit use of -\&\fB$\fR with the option \fB\-fno-dollars-in-identifiers\fR. (\s-1GNU\s0 C allows -\&\fB$\fR by default on most target systems, but there are a few exceptions.) -Traditional C allowed the character \fB$\fR to form part of -identifiers. However, \s-1ISO\s0 C and \*(C+ forbid \fB$\fR in identifiers. -.Ip "\fB\-fno-elide-constructors\fR" 4 -.IX Item "-fno-elide-constructors" -The \*(C+ standard allows an implementation to omit creating a temporary -which is only used to initialize another object of the same type. -Specifying this option disables that optimization, and forces G++ to -call the copy constructor in all cases. -.Ip "\fB\-fno-enforce-eh-specs\fR" 4 -.IX Item "-fno-enforce-eh-specs" -Don't check for violation of exception specifications at runtime. This -option violates the \*(C+ standard, but may be useful for reducing code -size in production builds, much like defining \fB\s-1NDEBUG\s0\fR. The compiler -will still optimize based on the exception specifications. -.Ip "\fB\-fexternal-templates\fR" 4 -.IX Item "-fexternal-templates" -Cause \fB#pragma interface\fR and \fBimplementation\fR to apply to -template instantiation; template instances are emitted or not according -to the location of the template definition. -.Sp -This option is deprecated. -.Ip "\fB\-falt-external-templates\fR" 4 -.IX Item "-falt-external-templates" -Similar to \fB\-fexternal-templates\fR, but template instances are -emitted or not according to the place where they are first instantiated. -.Sp -This option is deprecated. -.Ip "\fB\-ffor-scope\fR" 4 -.IX Item "-ffor-scope" -.PD 0 -.Ip "\fB\-fno-for-scope\fR" 4 -.IX Item "-fno-for-scope" -.PD -If \fB\-ffor-scope\fR is specified, the scope of variables declared in -a \fIfor-init-statement\fR is limited to the \fBfor\fR loop itself, -as specified by the \*(C+ standard. -If \fB\-fno-for-scope\fR is specified, the scope of variables declared in -a \fIfor-init-statement\fR extends to the end of the enclosing scope, -as was the case in old versions of G++, and other (traditional) -implementations of \*(C+. -.Sp -The default if neither flag is given to follow the standard, -but to allow and give a warning for old-style code that would -otherwise be invalid, or have different behavior. -.Ip "\fB\-fno-gnu-keywords\fR" 4 -.IX Item "-fno-gnu-keywords" -Do not recognize \f(CW\*(C`typeof\*(C'\fR as a keyword, so that code can use this -word as an identifier. You can use the keyword \f(CW\*(C`_\|_typeof_\|_\*(C'\fR instead. -\&\fB\-ansi\fR implies \fB\-fno-gnu-keywords\fR. -.Ip "\fB\-fno-implicit-templates\fR" 4 -.IX Item "-fno-implicit-templates" -Never emit code for non-inline templates which are instantiated -implicitly (i.e. by use); only emit code for explicit instantiations. -.Ip "\fB\-fno-implicit-inline-templates\fR" 4 -.IX Item "-fno-implicit-inline-templates" -Don't emit code for implicit instantiations of inline templates, either. -The default is to handle inlines differently so that compiles with and -without optimization will need the same set of explicit instantiations. -.Ip "\fB\-fno-implement-inlines\fR" 4 -.IX Item "-fno-implement-inlines" -To save space, do not emit out-of-line copies of inline functions -controlled by \fB#pragma implementation\fR. This will cause linker -errors if these functions are not inlined everywhere they are called. -.Ip "\fB\-fms-extensions\fR" 4 -.IX Item "-fms-extensions" -Disable pedantic warnings about constructs used in \s-1MFC\s0, such as implicit -int and getting a pointer to member function via non-standard syntax. -.Ip "\fB\-fno-nonansi-builtins\fR" 4 -.IX Item "-fno-nonansi-builtins" -Disable built-in declarations of functions that are not mandated by -\&\s-1ANSI/ISO\s0 C. These include \f(CW\*(C`ffs\*(C'\fR, \f(CW\*(C`alloca\*(C'\fR, \f(CW\*(C`_exit\*(C'\fR, -\&\f(CW\*(C`index\*(C'\fR, \f(CW\*(C`bzero\*(C'\fR, \f(CW\*(C`conjf\*(C'\fR, and other related functions. -.Ip "\fB\-fno-operator-names\fR" 4 -.IX Item "-fno-operator-names" -Do not treat the operator name keywords \f(CW\*(C`and\*(C'\fR, \f(CW\*(C`bitand\*(C'\fR, -\&\f(CW\*(C`bitor\*(C'\fR, \f(CW\*(C`compl\*(C'\fR, \f(CW\*(C`not\*(C'\fR, \f(CW\*(C`or\*(C'\fR and \f(CW\*(C`xor\*(C'\fR as -synonyms as keywords. -.Ip "\fB\-fno-optional-diags\fR" 4 -.IX Item "-fno-optional-diags" -Disable diagnostics that the standard says a compiler does not need to -issue. Currently, the only such diagnostic issued by G++ is the one for -a name having multiple meanings within a class. -.Ip "\fB\-fpermissive\fR" 4 -.IX Item "-fpermissive" -Downgrade messages about nonconformant code from errors to warnings. By -default, G++ effectively sets \fB\-pedantic-errors\fR without -\&\fB\-pedantic\fR; this option reverses that. This behavior and this -option are superseded by \fB\-pedantic\fR, which works as it does for \s-1GNU\s0 C. -.Ip "\fB\-frepo\fR" 4 -.IX Item "-frepo" -Enable automatic template instantiation at link time. This option also -implies \fB\-fno-implicit-templates\fR. -.Ip "\fB\-fno-rtti\fR" 4 -.IX Item "-fno-rtti" -Disable generation of information about every class with virtual -functions for use by the \*(C+ runtime type identification features -(\fBdynamic_cast\fR and \fBtypeid\fR). If you don't use those parts -of the language, you can save some space by using this flag. Note that -exception handling uses the same information, but it will generate it as -needed. -.Ip "\fB\-fstats\fR" 4 -.IX Item "-fstats" -Emit statistics about front-end processing at the end of the compilation. -This information is generally only useful to the G++ development team. -.Ip "\fB\-ftemplate-depth-\fR\fIn\fR" 4 -.IX Item "-ftemplate-depth-n" -Set the maximum instantiation depth for template classes to \fIn\fR. -A limit on the template instantiation depth is needed to detect -endless recursions during template class instantiation. \s-1ANSI/ISO\s0 \*(C+ -conforming programs must not rely on a maximum depth greater than 17. -.Ip "\fB\-fuse-cxa-atexit\fR" 4 -.IX Item "-fuse-cxa-atexit" -Register destructors for objects with static storage duration with the -\&\f(CW\*(C`_\|_cxa_atexit\*(C'\fR function rather than the \f(CW\*(C`atexit\*(C'\fR function. -This option is required for fully standards-compliant handling of static -destructors, but will only work if your C library supports -\&\f(CW\*(C`_\|_cxa_atexit\*(C'\fR. -.Ip "\fB\-fvtable-gc\fR" 4 -.IX Item "-fvtable-gc" -Emit special relocations for vtables and virtual function references -so that the linker can identify unused virtual functions and zero out -vtable slots that refer to them. This is most useful with -\&\fB\-ffunction-sections\fR and \fB\-Wl,\-\-gc-sections\fR, in order to -also discard the functions themselves. -.Sp -This optimization requires \s-1GNU\s0 as and \s-1GNU\s0 ld. Not all systems support -this option. \fB\-Wl,\-\-gc-sections\fR is ignored without \fB\-static\fR. -.Ip "\fB\-fno-weak\fR" 4 -.IX Item "-fno-weak" -Do not use weak symbol support, even if it is provided by the linker. -By default, G++ will use weak symbols if they are available. This -option exists only for testing, and should not be used by end-users; -it will result in inferior code and has no benefits. This option may -be removed in a future release of G++. -.Ip "\fB\-nostdinc++\fR" 4 -.IX Item "-nostdinc++" -Do not search for header files in the standard directories specific to -\&\*(C+, but do still search the other standard directories. (This option -is used when building the \*(C+ library.) -.PP -In addition, these optimization, warning, and code generation options -have meanings only for \*(C+ programs: -.Ip "\fB\-fno-default-inline\fR" 4 -.IX Item "-fno-default-inline" -Do not assume \fBinline\fR for functions defined inside a class scope. - Note that these -functions will have linkage like inline functions; they just won't be -inlined by default. -.Ip "\fB\-Wabi\fR (\*(C+ only)" 4 -.IX Item "-Wabi ( only)" -Warn when G++ generates code that is probably not compatible with the -vendor-neutral \*(C+ \s-1ABI\s0. Although an effort has been made to warn about -all such cases, there are probably some cases that are not warned about, -even though G++ is generating incompatible code. There may also be -cases where warnings are emitted even though the code that is generated -will be compatible. -.Sp -You should rewrite your code to avoid these warnings if you are -concerned about the fact that code generated by G++ may not be binary -compatible with code generated by other compilers. -.Sp -The known incompatibilites at this point include: -.RS 4 -.Ip "\(bu" 4 -Incorrect handling of tail-padding for bit-fields. G++ may attempt to -pack data into the same byte as a base class. For example: -.Sp -.Vb 2 -\& struct A { virtual void f(); int f1 : 1; }; -\& struct B : public A { int f2 : 1; }; -.Ve -In this case, G++ will place \f(CW\*(C`B::f2\*(C'\fR into the same byte -as\f(CW\*(C`A::f1\*(C'\fR; other compilers will not. You can avoid this problem -by explicitly padding \f(CW\*(C`A\*(C'\fR so that its size is a multiple of the -byte size on your platform; that will cause G++ and other compilers to -layout \f(CW\*(C`B\*(C'\fR identically. -.Ip "\(bu" 4 -Incorrect handling of tail-padding for virtual bases. G++ does not use -tail padding when laying out virtual bases. For example: -.Sp -.Vb 3 -\& struct A { virtual void f(); char c1; }; -\& struct B { B(); char c2; }; -\& struct C : public A, public virtual B {}; -.Ve -In this case, G++ will not place \f(CW\*(C`B\*(C'\fR into the tail-padding for -\&\f(CW\*(C`A\*(C'\fR; other compilers will. You can avoid this problem by -explicitly padding \f(CW\*(C`A\*(C'\fR so that its size is a multiple of its -alignment (ignoring virtual base classes); that will cause G++ and other -compilers to layout \f(CW\*(C`C\*(C'\fR identically. -.RE -.RS 4 -.RE -.Ip "\fB\-Wctor-dtor-privacy\fR (\*(C+ only)" 4 -.IX Item "-Wctor-dtor-privacy ( only)" -Warn when a class seems unusable, because all the constructors or -destructors in a class are private and the class has no friends or -public static member functions. -.Ip "\fB\-Wnon-virtual-dtor\fR (\*(C+ only)" 4 -.IX Item "-Wnon-virtual-dtor ( only)" -Warn when a class declares a non-virtual destructor that should probably -be virtual, because it looks like the class will be used polymorphically. -.Ip "\fB\-Wreorder\fR (\*(C+ only)" 4 -.IX Item "-Wreorder ( only)" -Warn when the order of member initializers given in the code does not -match the order in which they must be executed. For instance: -.Sp -.Vb 5 -\& struct A { -\& int i; -\& int j; -\& A(): j (0), i (1) { } -\& }; -.Ve -Here the compiler will warn that the member initializers for \fBi\fR -and \fBj\fR will be rearranged to match the declaration order of the -members. -.PP -The following \fB\-W...\fR options are not affected by \fB\-Wall\fR. -.Ip "\fB\-Weffc++\fR (\*(C+ only)" 4 -.IX Item "-Weffc++ ( only)" -Warn about violations of the following style guidelines from Scott Meyers' -\&\fIEffective \*(C+\fR book: -.RS 4 -.Ip "\(bu" 4 -Item 11: Define a copy constructor and an assignment operator for classes -with dynamically allocated memory. -.Ip "\(bu" 4 -Item 12: Prefer initialization to assignment in constructors. -.Ip "\(bu" 4 -Item 14: Make destructors virtual in base classes. -.Ip "\(bu" 4 -Item 15: Have \f(CW\*(C`operator=\*(C'\fR return a reference to \f(CW\*(C`*this\*(C'\fR. -.Ip "\(bu" 4 -Item 23: Don't try to return a reference when you must return an object. -.RE -.RS 4 -.Sp -and about violations of the following style guidelines from Scott Meyers' -\&\fIMore Effective \*(C+\fR book: -.RS 4 -.RE -.Ip "\(bu" 4 -Item 6: Distinguish between prefix and postfix forms of increment and -decrement operators. -.Ip "\(bu" 4 -Item 7: Never overload \f(CW\*(C`&&\*(C'\fR, \f(CW\*(C`||\*(C'\fR, or \f(CW\*(C`,\*(C'\fR. -.RE -.RS 4 -.Sp -If you use this option, you should be aware that the standard library -headers do not obey all of these guidelines; you can use \fBgrep \-v\fR -to filter out those warnings. -.RE -.Ip "\fB\-Wno-deprecated\fR (\*(C+ only)" 4 -.IX Item "-Wno-deprecated ( only)" -Do not warn about usage of deprecated features. -.Ip "\fB\-Wno-non-template-friend\fR (\*(C+ only)" 4 -.IX Item "-Wno-non-template-friend ( only)" -Disable warnings when non-templatized friend functions are declared -within a template. With the advent of explicit template specification -support in G++, if the name of the friend is an unqualified-id (i.e., -\&\fBfriend foo(int)\fR), the \*(C+ language specification demands that the -friend declare or define an ordinary, nontemplate function. (Section -14.5.3). Before G++ implemented explicit specification, unqualified-ids -could be interpreted as a particular specialization of a templatized -function. Because this non-conforming behavior is no longer the default -behavior for G++, \fB\-Wnon-template-friend\fR allows the compiler to -check existing code for potential trouble spots, and is on by default. -This new compiler behavior can be turned off with -\&\fB\-Wno-non-template-friend\fR which keeps the conformant compiler code -but disables the helpful warning. -.Ip "\fB\-Wold-style-cast\fR (\*(C+ only)" 4 -.IX Item "-Wold-style-cast ( only)" -Warn if an old-style (C-style) cast to a non-void type is used within -a \*(C+ program. The new-style casts (\fBstatic_cast\fR, -\&\fBreinterpret_cast\fR, and \fBconst_cast\fR) are less vulnerable to -unintended effects, and much easier to grep for. -.Ip "\fB\-Woverloaded-virtual\fR (\*(C+ only)" 4 -.IX Item "-Woverloaded-virtual ( only)" -Warn when a function declaration hides virtual functions from a -base class. For example, in: -.Sp -.Vb 3 -\& struct A { -\& virtual void f(); -\& }; -.Ve -.Vb 3 -\& struct B: public A { -\& void f(int); -\& }; -.Ve -the \f(CW\*(C`A\*(C'\fR class version of \f(CW\*(C`f\*(C'\fR is hidden in \f(CW\*(C`B\*(C'\fR, and code -like this: -.Sp -.Vb 2 -\& B* b; -\& b->f(); -.Ve -will fail to compile. -.Ip "\fB\-Wno-pmf-conversions\fR (\*(C+ only)" 4 -.IX Item "-Wno-pmf-conversions ( only)" -Disable the diagnostic for converting a bound pointer to member function -to a plain pointer. -.Ip "\fB\-Wsign-promo\fR (\*(C+ only)" 4 -.IX Item "-Wsign-promo ( only)" -Warn when overload resolution chooses a promotion from unsigned or -enumeral type to a signed type over a conversion to an unsigned type of -the same size. Previous versions of G++ would try to preserve -unsignedness, but the standard mandates the current behavior. -.Ip "\fB\-Wsynth\fR (\*(C+ only)" 4 -.IX Item "-Wsynth ( only)" -Warn when G++'s synthesis behavior does not match that of cfront. For -instance: -.Sp -.Vb 4 -\& struct A { -\& operator int (); -\& A& operator = (int); -\& }; -.Ve -.Vb 5 -\& main () -\& { -\& A a,b; -\& a = b; -\& } -.Ve -In this example, G++ will synthesize a default \fBA& operator = -(const A&);\fR, while cfront will use the user-defined \fBoperator =\fR. -.Sh "Options Controlling Objective-C Dialect" -.IX Subsection "Options Controlling Objective-C Dialect" -This section describes the command-line options that are only meaningful -for Objective-C programs; but you can also use most of the \s-1GNU\s0 compiler -options regardless of what language your program is in. For example, -you might compile a file \f(CW\*(C`some_class.m\*(C'\fR like this: -.PP -.Vb 1 -\& gcc -g -fgnu-runtime -O -c some_class.m -.Ve -In this example, only \fB\-fgnu-runtime\fR is an option meant only for -Objective-C programs; you can use the other options with any language -supported by \s-1GCC\s0. -.PP -Here is a list of options that are \fIonly\fR for compiling Objective-C -programs: -.Ip "\fB\-fconstant-string-class=\fR\fIclass-name\fR" 4 -.IX Item "-fconstant-string-class=class-name" -Use \fIclass-name\fR as the name of the class to instantiate for each -literal string specified with the syntax \f(CW\*(C`@"..."\*(C'\fR. The default -class name is \f(CW\*(C`NXConstantString\*(C'\fR. -.Ip "\fB\-fgnu-runtime\fR" 4 -.IX Item "-fgnu-runtime" -Generate object code compatible with the standard \s-1GNU\s0 Objective-C -runtime. This is the default for most types of systems. -.Ip "\fB\-fnext-runtime\fR" 4 -.IX Item "-fnext-runtime" -Generate output compatible with the NeXT runtime. This is the default -for NeXT-based systems, including Darwin and Mac \s-1OS\s0 X. -.Ip "\fB\-gen-decls\fR" 4 -.IX Item "-gen-decls" -Dump interface declarations for all classes seen in the source file to a -file named \fI\fIsourcename\fI.decl\fR. -.Ip "\fB\-Wno-protocol\fR" 4 -.IX Item "-Wno-protocol" -Do not warn if methods required by a protocol are not implemented -in the class adopting it. -.Ip "\fB\-Wselector\fR" 4 -.IX Item "-Wselector" -Warn if a selector has multiple methods of different types defined. -.Sh "Options to Control Diagnostic Messages Formatting" -.IX Subsection "Options to Control Diagnostic Messages Formatting" -Traditionally, diagnostic messages have been formatted irrespective of -the output device's aspect (e.g. its width, ...). The options described -below can be used to control the diagnostic messages formatting -algorithm, e.g. how many characters per line, how often source location -information should be reported. Right now, only the \*(C+ front end can -honor these options. However it is expected, in the near future, that -the remaining front ends would be able to digest them correctly. -.Ip "\fB\-fmessage-length=\fR\fIn\fR" 4 -.IX Item "-fmessage-length=n" -Try to format error messages so that they fit on lines of about \fIn\fR -characters. The default is 72 characters for \fBg++\fR and 0 for the rest of -the front ends supported by \s-1GCC\s0. If \fIn\fR is zero, then no -line-wrapping will be done; each error message will appear on a single -line. -.Ip "\fB\-fdiagnostics-show-location=once\fR" 4 -.IX Item "-fdiagnostics-show-location=once" -Only meaningful in line-wrapping mode. Instructs the diagnostic messages -reporter to emit \fIonce\fR source location information; that is, in -case the message is too long to fit on a single physical line and has to -be wrapped, the source location won't be emitted (as prefix) again, -over and over, in subsequent continuation lines. This is the default -behavior. -.Ip "\fB\-fdiagnostics-show-location=every-line\fR" 4 -.IX Item "-fdiagnostics-show-location=every-line" -Only meaningful in line-wrapping mode. Instructs the diagnostic -messages reporter to emit the same source location information (as -prefix) for physical lines that result from the process of breaking -a message which is too long to fit on a single line. -.Sh "Options to Request or Suppress Warnings" -.IX Subsection "Options to Request or Suppress Warnings" -Warnings are diagnostic messages that report constructions which -are not inherently erroneous but which are risky or suggest there -may have been an error. -.PP -You can request many specific warnings with options beginning \fB\-W\fR, -for example \fB\-Wimplicit\fR to request warnings on implicit -declarations. Each of these specific warning options also has a -negative form beginning \fB\-Wno-\fR to turn off warnings; -for example, \fB\-Wno-implicit\fR. This manual lists only one of the -two forms, whichever is not the default. -.PP -The following options control the amount and kinds of warnings produced -by \s-1GCC\s0; for further, language-specific options also refer to -\&\f(CW@ref\fR{\*(C+ Dialect Options} and \f(CW@ref\fR{Objective-C Dialect Options}. -.Ip "\fB\-fsyntax-only\fR" 4 -.IX Item "-fsyntax-only" -Check the code for syntax errors, but don't do anything beyond that. -.Ip "\fB\-pedantic\fR" 4 -.IX Item "-pedantic" -Issue all the warnings demanded by strict \s-1ISO\s0 C and \s-1ISO\s0 \*(C+; -reject all programs that use forbidden extensions, and some other -programs that do not follow \s-1ISO\s0 C and \s-1ISO\s0 \*(C+. For \s-1ISO\s0 C, follows the -version of the \s-1ISO\s0 C standard specified by any \fB\-std\fR option used. -.Sp -Valid \s-1ISO\s0 C and \s-1ISO\s0 \*(C+ programs should compile properly with or without -this option (though a rare few will require \fB\-ansi\fR or a -\&\fB\-std\fR option specifying the required version of \s-1ISO\s0 C). However, -without this option, certain \s-1GNU\s0 extensions and traditional C and \*(C+ -features are supported as well. With this option, they are rejected. -.Sp -\&\fB\-pedantic\fR does not cause warning messages for use of the -alternate keywords whose names begin and end with \fB_\|_\fR. Pedantic -warnings are also disabled in the expression that follows -\&\f(CW\*(C`_\|_extension_\|_\*(C'\fR. However, only system header files should use -these escape routes; application programs should avoid them. -.Sp -Some users try to use \fB\-pedantic\fR to check programs for strict \s-1ISO\s0 -C conformance. They soon find that it does not do quite what they want: -it finds some non-ISO practices, but not all\-\-\-only those for which -\&\s-1ISO\s0 C \fIrequires\fR a diagnostic, and some others for which -diagnostics have been added. -.Sp -A feature to report any failure to conform to \s-1ISO\s0 C might be useful in -some instances, but would require considerable additional work and would -be quite different from \fB\-pedantic\fR. We don't have plans to -support such a feature in the near future. -.Sp -Where the standard specified with \fB\-std\fR represents a \s-1GNU\s0 -extended dialect of C, such as \fBgnu89\fR or \fBgnu99\fR, there is a -corresponding \fIbase standard\fR, the version of \s-1ISO\s0 C on which the \s-1GNU\s0 -extended dialect is based. Warnings from \fB\-pedantic\fR are given -where they are required by the base standard. (It would not make sense -for such warnings to be given only for features not in the specified \s-1GNU\s0 -C dialect, since by definition the \s-1GNU\s0 dialects of C include all -features the compiler supports with the given option, and there would be -nothing to warn about.) -.Ip "\fB\-pedantic-errors\fR" 4 -.IX Item "-pedantic-errors" -Like \fB\-pedantic\fR, except that errors are produced rather than -warnings. -.Ip "\fB\-w\fR" 4 -.IX Item "-w" -Inhibit all warning messages. -.Ip "\fB\-Wno-import\fR" 4 -.IX Item "-Wno-import" -Inhibit warning messages about the use of \fB#import\fR. -.Ip "\fB\-Wchar-subscripts\fR" 4 -.IX Item "-Wchar-subscripts" -Warn if an array subscript has type \f(CW\*(C`char\*(C'\fR. This is a common cause -of error, as programmers often forget that this type is signed on some -machines. -.Ip "\fB\-Wcomment\fR" 4 -.IX Item "-Wcomment" -Warn whenever a comment-start sequence \fB/*\fR appears in a \fB/*\fR -comment, or whenever a Backslash-Newline appears in a \fB//\fR comment. -.Ip "\fB\-Wformat\fR" 4 -.IX Item "-Wformat" -Check calls to \f(CW\*(C`printf\*(C'\fR and \f(CW\*(C`scanf\*(C'\fR, etc., to make sure that -the arguments supplied have types appropriate to the format string -specified, and that the conversions specified in the format string make -sense. This includes standard functions, and others specified by format -attributes, in the \f(CW\*(C`printf\*(C'\fR, -\&\f(CW\*(C`scanf\*(C'\fR, \f(CW\*(C`strftime\*(C'\fR and \f(CW\*(C`strfmon\*(C'\fR (an X/Open extension, -not in the C standard) families. -.Sp -The formats are checked against the format features supported by \s-1GNU\s0 -libc version 2.2. These include all \s-1ISO\s0 C89 and C99 features, as well -as features from the Single Unix Specification and some \s-1BSD\s0 and \s-1GNU\s0 -extensions. Other library implementations may not support all these -features; \s-1GCC\s0 does not support warning about features that go beyond a -particular library's limitations. However, if \fB\-pedantic\fR is used -with \fB\-Wformat\fR, warnings will be given about format features not -in the selected standard version (but not for \f(CW\*(C`strfmon\*(C'\fR formats, -since those are not in any version of the C standard). -.Sp -\&\fB\-Wformat\fR is included in \fB\-Wall\fR. For more control over some -aspects of format checking, the options \fB\-Wno-format-y2k\fR, -\&\fB\-Wno-format-extra-args\fR, \fB\-Wformat-nonliteral\fR, -\&\fB\-Wformat-security\fR and \fB\-Wformat=2\fR are available, but are -not included in \fB\-Wall\fR. -.Ip "\fB\-Wno-format-y2k\fR" 4 -.IX Item "-Wno-format-y2k" -If \fB\-Wformat\fR is specified, do not warn about \f(CW\*(C`strftime\*(C'\fR -formats which may yield only a two-digit year. -.Ip "\fB\-Wno-format-extra-args\fR" 4 -.IX Item "-Wno-format-extra-args" -If \fB\-Wformat\fR is specified, do not warn about excess arguments to a -\&\f(CW\*(C`printf\*(C'\fR or \f(CW\*(C`scanf\*(C'\fR format function. The C standard specifies -that such arguments are ignored. -.Sp -Where the unused arguments lie between used arguments that are -specified with \fB$\fR operand number specifications, normally -warnings are still given, since the implementation could not know what -type to pass to \f(CW\*(C`va_arg\*(C'\fR to skip the unused arguments. However, -in the case of \f(CW\*(C`scanf\*(C'\fR formats, this option will suppress the -warning if the unused arguments are all pointers, since the Single -Unix Specification says that such unused arguments are allowed. -.Ip "\fB\-Wformat-nonliteral\fR" 4 -.IX Item "-Wformat-nonliteral" -If \fB\-Wformat\fR is specified, also warn if the format string is not a -string literal and so cannot be checked, unless the format function -takes its format arguments as a \f(CW\*(C`va_list\*(C'\fR. -.Ip "\fB\-Wformat-security\fR" 4 -.IX Item "-Wformat-security" -If \fB\-Wformat\fR is specified, also warn about uses of format -functions that represent possible security problems. At present, this -warns about calls to \f(CW\*(C`printf\*(C'\fR and \f(CW\*(C`scanf\*(C'\fR functions where the -format string is not a string literal and there are no format arguments, -as in \f(CW\*(C`printf (foo);\*(C'\fR. This may be a security hole if the format -string came from untrusted input and contains \fB%n\fR. (This is -currently a subset of what \fB\-Wformat-nonliteral\fR warns about, but -in future warnings may be added to \fB\-Wformat-security\fR that are not -included in \fB\-Wformat-nonliteral\fR.) -.Ip "\fB\-Wformat=2\fR" 4 -.IX Item "-Wformat=2" -Enable \fB\-Wformat\fR plus format checks not included in -\&\fB\-Wformat\fR. Currently equivalent to \fB\-Wformat -\&\-Wformat-nonliteral \-Wformat-security\fR. -.Ip "\fB\-Wimplicit-int\fR" 4 -.IX Item "-Wimplicit-int" -Warn when a declaration does not specify a type. -.Ip "\fB\-Wimplicit-function-declaration\fR" 4 -.IX Item "-Wimplicit-function-declaration" -.PD 0 -.Ip "\fB\-Werror-implicit-function-declaration\fR" 4 -.IX Item "-Werror-implicit-function-declaration" -.PD -Give a warning (or error) whenever a function is used before being -declared. -.Ip "\fB\-Wimplicit\fR" 4 -.IX Item "-Wimplicit" -Same as \fB\-Wimplicit-int\fR and \fB\-Wimplicit-function-declaration\fR. -.Ip "\fB\-Wmain\fR" 4 -.IX Item "-Wmain" -Warn if the type of \fBmain\fR is suspicious. \fBmain\fR should be a -function with external linkage, returning int, taking either zero -arguments, two, or three arguments of appropriate types. -.Ip "\fB\-Wmissing-braces\fR" 4 -.IX Item "-Wmissing-braces" -Warn if an aggregate or union initializer is not fully bracketed. In -the following example, the initializer for \fBa\fR is not fully -bracketed, but that for \fBb\fR is fully bracketed. -.Sp -.Vb 2 -\& int a[2][2] = { 0, 1, 2, 3 }; -\& int b[2][2] = { { 0, 1 }, { 2, 3 } }; -.Ve -.Ip "\fB\-Wparentheses\fR" 4 -.IX Item "-Wparentheses" -Warn if parentheses are omitted in certain contexts, such -as when there is an assignment in a context where a truth value -is expected, or when operators are nested whose precedence people -often get confused about. -.Sp -Also warn about constructions where there may be confusion to which -\&\f(CW\*(C`if\*(C'\fR statement an \f(CW\*(C`else\*(C'\fR branch belongs. Here is an example of -such a case: -.Sp -.Vb 7 -\& { -\& if (a) -\& if (b) -\& foo (); -\& else -\& bar (); -\& } -.Ve -In C, every \f(CW\*(C`else\*(C'\fR branch belongs to the innermost possible \f(CW\*(C`if\*(C'\fR -statement, which in this example is \f(CW\*(C`if (b)\*(C'\fR. This is often not -what the programmer expected, as illustrated in the above example by -indentation the programmer chose. When there is the potential for this -confusion, \s-1GCC\s0 will issue a warning when this flag is specified. -To eliminate the warning, add explicit braces around the innermost -\&\f(CW\*(C`if\*(C'\fR statement so there is no way the \f(CW\*(C`else\*(C'\fR could belong to -the enclosing \f(CW\*(C`if\*(C'\fR. The resulting code would look like this: -.Sp -.Vb 9 -\& { -\& if (a) -\& { -\& if (b) -\& foo (); -\& else -\& bar (); -\& } -\& } -.Ve -.Ip "\fB\-Wsequence-point\fR" 4 -.IX Item "-Wsequence-point" -Warn about code that may have undefined semantics because of violations -of sequence point rules in the C standard. -.Sp -The C standard defines the order in which expressions in a C program are -evaluated in terms of \fIsequence points\fR, which represent a partial -ordering between the execution of parts of the program: those executed -before the sequence point, and those executed after it. These occur -after the evaluation of a full expression (one which is not part of a -larger expression), after the evaluation of the first operand of a -\&\f(CW\*(C`&&\*(C'\fR, \f(CW\*(C`||\*(C'\fR, \f(CW\*(C`? :\*(C'\fR or \f(CW\*(C`,\*(C'\fR (comma) operator, before a -function is called (but after the evaluation of its arguments and the -expression denoting the called function), and in certain other places. -Other than as expressed by the sequence point rules, the order of -evaluation of subexpressions of an expression is not specified. All -these rules describe only a partial order rather than a total order, -since, for example, if two functions are called within one expression -with no sequence point between them, the order in which the functions -are called is not specified. However, the standards committee have -ruled that function calls do not overlap. -.Sp -It is not specified when between sequence points modifications to the -values of objects take effect. Programs whose behavior depends on this -have undefined behavior; the C standard specifies that ``Between the -previous and next sequence point an object shall have its stored value -modified at most once by the evaluation of an expression. Furthermore, -the prior value shall be read only to determine the value to be -stored.''. If a program breaks these rules, the results on any -particular implementation are entirely unpredictable. -.Sp -Examples of code with undefined behavior are \f(CW\*(C`a = a++;\*(C'\fR, \f(CW\*(C`a[n] -= b[n++]\*(C'\fR and \f(CW\*(C`a[i++] = i;\*(C'\fR. Some more complicated cases are not -diagnosed by this option, and it may give an occasional false positive -result, but in general it has been found fairly effective at detecting -this sort of problem in programs. -.Sp -The present implementation of this option only works for C programs. A -future implementation may also work for \*(C+ programs. -.Sp -The C standard is worded confusingly, therefore there is some debate -over the precise meaning of the sequence point rules in subtle cases. -Links to discussions of the problem, including proposed formal -definitions, may be found on our readings page, at -<\fBhttp://gcc.gnu.org/readings.html\fR>. -.Ip "\fB\-Wreturn-type\fR" 4 -.IX Item "-Wreturn-type" -Warn whenever a function is defined with a return-type that defaults to -\&\f(CW\*(C`int\*(C'\fR. Also warn about any \f(CW\*(C`return\*(C'\fR statement with no -return-value in a function whose return-type is not \f(CW\*(C`void\*(C'\fR. -.Sp -For \*(C+, a function without return type always produces a diagnostic -message, even when \fB\-Wno-return-type\fR is specified. The only -exceptions are \fBmain\fR and functions defined in system headers. -.Ip "\fB\-Wswitch\fR" 4 -.IX Item "-Wswitch" -Warn whenever a \f(CW\*(C`switch\*(C'\fR statement has an index of enumeral type -and lacks a \f(CW\*(C`case\*(C'\fR for one or more of the named codes of that -enumeration. (The presence of a \f(CW\*(C`default\*(C'\fR label prevents this -warning.) \f(CW\*(C`case\*(C'\fR labels outside the enumeration range also -provoke warnings when this option is used. -.Ip "\fB\-Wtrigraphs\fR" 4 -.IX Item "-Wtrigraphs" -Warn if any trigraphs are encountered that might change the meaning of -the program (trigraphs within comments are not warned about). -.Ip "\fB\-Wunused-function\fR" 4 -.IX Item "-Wunused-function" -Warn whenever a static function is declared but not defined or a -non\e-inline static function is unused. -.Ip "\fB\-Wunused-label\fR" 4 -.IX Item "-Wunused-label" -Warn whenever a label is declared but not used. -.Sp -To suppress this warning use the \fBunused\fR attribute. -.Ip "\fB\-Wunused-parameter\fR" 4 -.IX Item "-Wunused-parameter" -Warn whenever a function parameter is unused aside from its declaration. -.Sp -To suppress this warning use the \fBunused\fR attribute. -.Ip "\fB\-Wunused-variable\fR" 4 -.IX Item "-Wunused-variable" -Warn whenever a local variable or non-constant static variable is unused -aside from its declaration -.Sp -To suppress this warning use the \fBunused\fR attribute. -.Ip "\fB\-Wunused-value\fR" 4 -.IX Item "-Wunused-value" -Warn whenever a statement computes a result that is explicitly not used. -.Sp -To suppress this warning cast the expression to \fBvoid\fR. -.Ip "\fB\-Wunused\fR" 4 -.IX Item "-Wunused" -All all the above \fB\-Wunused\fR options combined. -.Sp -In order to get a warning about an unused function parameter, you must -either specify \fB\-W \-Wunused\fR or separately specify -\&\fB\-Wunused-parameter\fR. -.Ip "\fB\-Wuninitialized\fR" 4 -.IX Item "-Wuninitialized" -Warn if an automatic variable is used without first being initialized or -if a variable may be clobbered by a \f(CW\*(C`setjmp\*(C'\fR call. -.Sp -These warnings are possible only in optimizing compilation, -because they require data flow information that is computed only -when optimizing. If you don't specify \fB\-O\fR, you simply won't -get these warnings. -.Sp -These warnings occur only for variables that are candidates for -register allocation. Therefore, they do not occur for a variable that -is declared \f(CW\*(C`volatile\*(C'\fR, or whose address is taken, or whose size -is other than 1, 2, 4 or 8 bytes. Also, they do not occur for -structures, unions or arrays, even when they are in registers. -.Sp -Note that there may be no warning about a variable that is used only -to compute a value that itself is never used, because such -computations may be deleted by data flow analysis before the warnings -are printed. -.Sp -These warnings are made optional because \s-1GCC\s0 is not smart -enough to see all the reasons why the code might be correct -despite appearing to have an error. Here is one example of how -this can happen: -.Sp -.Vb 12 -\& { -\& int x; -\& switch (y) -\& { -\& case 1: x = 1; -\& break; -\& case 2: x = 4; -\& break; -\& case 3: x = 5; -\& } -\& foo (x); -\& } -.Ve -If the value of \f(CW\*(C`y\*(C'\fR is always 1, 2 or 3, then \f(CW\*(C`x\*(C'\fR is -always initialized, but \s-1GCC\s0 doesn't know this. Here is -another common case: -.Sp -.Vb 6 -\& { -\& int save_y; -\& if (change_y) save_y = y, y = new_y; -\& ... -\& if (change_y) y = save_y; -\& } -.Ve -This has no bug because \f(CW\*(C`save_y\*(C'\fR is used only if it is set. -.Sp -This option also warns when a non-volatile automatic variable might be -changed by a call to \f(CW\*(C`longjmp\*(C'\fR. These warnings as well are possible -only in optimizing compilation. -.Sp -The compiler sees only the calls to \f(CW\*(C`setjmp\*(C'\fR. It cannot know -where \f(CW\*(C`longjmp\*(C'\fR will be called; in fact, a signal handler could -call it at any point in the code. As a result, you may get a warning -even when there is in fact no problem because \f(CW\*(C`longjmp\*(C'\fR cannot -in fact be called at the place which would cause a problem. -.Sp -Some spurious warnings can be avoided if you declare all the functions -you use that never return as \f(CW\*(C`noreturn\*(C'\fR. -.Ip "\fB\-Wreorder\fR (\*(C+ only)" 4 -.IX Item "-Wreorder ( only)" -Warn when the order of member initializers given in the code does not -match the order in which they must be executed. For instance: -.Ip "\fB\-Wunknown-pragmas\fR" 4 -.IX Item "-Wunknown-pragmas" -Warn when a #pragma directive is encountered which is not understood by -\&\s-1GCC\s0. If this command line option is used, warnings will even be issued -for unknown pragmas in system header files. This is not the case if -the warnings were only enabled by the \fB\-Wall\fR command line option. -.Ip "\fB\-Wall\fR" 4 -.IX Item "-Wall" -All of the above \fB\-W\fR options combined. This enables all the -warnings about constructions that some users consider questionable, and -that are easy to avoid (or modify to prevent the warning), even in -conjunction with macros. -.Ip "\fB\-Wdiv-by-zero\fR" 4 -.IX Item "-Wdiv-by-zero" -Warn about compile-time integer division by zero. This is default. To -inhibit the warning messages, use \fB\-Wno-div-by-zero\fR. Floating -point division by zero is not warned about, as it can be a legitimate -way of obtaining infinities and NaNs. -.Ip "\fB\-Wmultichar\fR" 4 -.IX Item "-Wmultichar" -Warn if a multicharacter constant (\fB'\s-1FOOF\s0'\fR) is used. This is -default. To inhibit the warning messages, use \fB\-Wno-multichar\fR. -Usually they indicate a typo in the user's code, as they have -implementation-defined values, and should not be used in portable code. -.Ip "\fB\-Wsystem-headers\fR" 4 -.IX Item "-Wsystem-headers" -Print warning messages for constructs found in system header files. -Warnings from system headers are normally suppressed, on the assumption -that they usually do not indicate real problems and would only make the -compiler output harder to read. Using this command line option tells -\&\s-1GCC\s0 to emit warnings from system headers as if they occurred in user -code. However, note that using \fB\-Wall\fR in conjunction with this -option will \fInot\fR warn about unknown pragmas in system -headers\-\-\-for that, \fB\-Wunknown-pragmas\fR must also be used. -.PP -The following \fB\-W...\fR options are not implied by \fB\-Wall\fR. -Some of them warn about constructions that users generally do not -consider questionable, but which occasionally you might wish to check -for; others warn about constructions that are necessary or hard to avoid -in some cases, and there is no simple way to modify the code to suppress -the warning. -.Ip "\fB\-W\fR" 4 -.IX Item "-W" -Print extra warning messages for these events: -.RS 4 -.Ip "\(bu" 4 -A function can return either with or without a value. (Falling -off the end of the function body is considered returning without -a value.) For example, this function would evoke such a -warning: -.Sp -.Vb 5 -\& foo (a) -\& { -\& if (a > 0) -\& return a; -\& } -.Ve -.Ip "\(bu" 4 -An expression-statement or the left-hand side of a comma expression -contains no side effects. -To suppress the warning, cast the unused expression to void. -For example, an expression such as \fBx[i,j]\fR will cause a warning, -but \fBx[(void)i,j]\fR will not. -.Ip "\(bu" 4 -An unsigned value is compared against zero with \fB<\fR or \fB<=\fR. -.Ip "\(bu" 4 -A comparison like \fBx<=y<=z\fR appears; this is equivalent to -\&\fB(x<=y ? 1 : 0) <= z\fR, which is a different interpretation from -that of ordinary mathematical notation. -.Ip "\(bu" 4 -Storage-class specifiers like \f(CW\*(C`static\*(C'\fR are not the first things in -a declaration. According to the C Standard, this usage is obsolescent. -.Ip "\(bu" 4 -The return type of a function has a type qualifier such as \f(CW\*(C`const\*(C'\fR. -Such a type qualifier has no effect, since the value returned by a -function is not an lvalue. (But don't warn about the \s-1GNU\s0 extension of -\&\f(CW\*(C`volatile void\*(C'\fR return types. That extension will be warned about -if \fB\-pedantic\fR is specified.) -.Ip "\(bu" 4 -If \fB\-Wall\fR or \fB\-Wunused\fR is also specified, warn about unused -arguments. -.Ip "\(bu" 4 -A comparison between signed and unsigned values could produce an -incorrect result when the signed value is converted to unsigned. -(But don't warn if \fB\-Wno-sign-compare\fR is also specified.) -.Ip "\(bu" 4 -An aggregate has a partly bracketed initializer. -For example, the following code would evoke such a warning, -because braces are missing around the initializer for \f(CW\*(C`x.h\*(C'\fR: -.Sp -.Vb 3 -\& struct s { int f, g; }; -\& struct t { struct s h; int i; }; -\& struct t x = { 1, 2, 3 }; -.Ve -.Ip "\(bu" 4 -An aggregate has an initializer which does not initialize all members. -For example, the following code would cause such a warning, because -\&\f(CW\*(C`x.h\*(C'\fR would be implicitly initialized to zero: -.Sp -.Vb 2 -\& struct s { int f, g, h; }; -\& struct s x = { 3, 4 }; -.Ve -.RE -.RS 4 -.RE -.Ip "\fB\-Wfloat-equal\fR" 4 -.IX Item "-Wfloat-equal" -Warn if floating point values are used in equality comparisons. -.Sp -The idea behind this is that sometimes it is convenient (for the -programmer) to consider floating-point values as approximations to -infinitely precise real numbers. If you are doing this, then you need -to compute (by analysing the code, or in some other way) the maximum or -likely maximum error that the computation introduces, and allow for it -when performing comparisons (and when producing output, but that's a -different problem). In particular, instead of testing for equality, you -would check to see whether the two values have ranges that overlap; and -this is done with the relational operators, so equality comparisons are -probably mistaken. -.Ip "\fB\-Wtraditional\fR (C only)" 4 -.IX Item "-Wtraditional (C only)" -Warn about certain constructs that behave differently in traditional and -\&\s-1ISO\s0 C. Also warn about \s-1ISO\s0 C constructs that have no traditional C -equivalent, and/or problematic constructs which should be avoided. -.RS 4 -.Ip "\(bu" 4 -Macro parameters that appear within string literals in the macro body. -In traditional C macro replacement takes place within string literals, -but does not in \s-1ISO\s0 C. -.Ip "\(bu" 4 -In traditional C, some preprocessor directives did not exist. -Traditional preprocessors would only consider a line to be a directive -if the \fB#\fR appeared in column 1 on the line. Therefore -\&\fB\-Wtraditional\fR warns about directives that traditional C -understands but would ignore because the \fB#\fR does not appear as the -first character on the line. It also suggests you hide directives like -\&\fB#pragma\fR not understood by traditional C by indenting them. Some -traditional implementations would not recognize \fB#elif\fR, so it -suggests avoiding it altogether. -.Ip "\(bu" 4 -A function-like macro that appears without arguments. -.Ip "\(bu" 4 -The unary plus operator. -.Ip "\(bu" 4 -The \fBU\fR integer constant suffix, or the \fBF\fR or \fBL\fR floating point -constant suffixes. (Traditional C does support the \fBL\fR suffix on integer -constants.) Note, these suffixes appear in macros defined in the system -headers of most modern systems, e.g. the \fB_MIN\fR/\fB_MAX\fR macros in \f(CW\*(C`<limits.h>\*(C'\fR. -Use of these macros in user code might normally lead to spurious -warnings, however gcc's integrated preprocessor has enough context to -avoid warning in these cases. -.Ip "\(bu" 4 -A function declared external in one block and then used after the end of -the block. -.Ip "\(bu" 4 -A \f(CW\*(C`switch\*(C'\fR statement has an operand of type \f(CW\*(C`long\*(C'\fR. -.Ip "\(bu" 4 -A non-\f(CW\*(C`static\*(C'\fR function declaration follows a \f(CW\*(C`static\*(C'\fR one. -This construct is not accepted by some traditional C compilers. -.Ip "\(bu" 4 -The \s-1ISO\s0 type of an integer constant has a different width or -signedness from its traditional type. This warning is only issued if -the base of the constant is ten. I.e. hexadecimal or octal values, which -typically represent bit patterns, are not warned about. -.Ip "\(bu" 4 -Usage of \s-1ISO\s0 string concatenation is detected. -.Ip "\(bu" 4 -Initialization of automatic aggregates. -.Ip "\(bu" 4 -Identifier conflicts with labels. Traditional C lacks a separate -namespace for labels. -.Ip "\(bu" 4 -Initialization of unions. If the initializer is zero, the warning is -omitted. This is done under the assumption that the zero initializer in -user code appears conditioned on e.g. \f(CW\*(C`_\|_STDC_\|_\*(C'\fR to avoid missing -initializer warnings and relies on default initialization to zero in the -traditional C case. -.Ip "\(bu" 4 -Conversions by prototypes between fixed/floating point values and vice -versa. The absence of these prototypes when compiling with traditional -C would cause serious problems. This is a subset of the possible -conversion warnings, for the full set use \fB\-Wconversion\fR. -.RE -.RS 4 -.RE -.Ip "\fB\-Wundef\fR" 4 -.IX Item "-Wundef" -Warn if an undefined identifier is evaluated in an \fB#if\fR directive. -.Ip "\fB\-Wshadow\fR" 4 -.IX Item "-Wshadow" -Warn whenever a local variable shadows another local variable, parameter or -global variable or whenever a built-in function is shadowed. -.Ip "\fB\-Wlarger-than-\fR\fIlen\fR" 4 -.IX Item "-Wlarger-than-len" -Warn whenever an object of larger than \fIlen\fR bytes is defined. -.Ip "\fB\-Wpointer-arith\fR" 4 -.IX Item "-Wpointer-arith" -Warn about anything that depends on the ``size of'' a function type or -of \f(CW\*(C`void\*(C'\fR. \s-1GNU\s0 C assigns these types a size of 1, for -convenience in calculations with \f(CW\*(C`void *\*(C'\fR pointers and pointers -to functions. -.Ip "\fB\-Wbad-function-cast\fR (C only)" 4 -.IX Item "-Wbad-function-cast (C only)" -Warn whenever a function call is cast to a non-matching type. -For example, warn if \f(CW\*(C`int malloc()\*(C'\fR is cast to \f(CW\*(C`anything *\*(C'\fR. -.Ip "\fB\-Wcast-qual\fR" 4 -.IX Item "-Wcast-qual" -Warn whenever a pointer is cast so as to remove a type qualifier from -the target type. For example, warn if a \f(CW\*(C`const char *\*(C'\fR is cast -to an ordinary \f(CW\*(C`char *\*(C'\fR. -.Ip "\fB\-Wcast-align\fR" 4 -.IX Item "-Wcast-align" -Warn whenever a pointer is cast such that the required alignment of the -target is increased. For example, warn if a \f(CW\*(C`char *\*(C'\fR is cast to -an \f(CW\*(C`int *\*(C'\fR on machines where integers can only be accessed at -two- or four-byte boundaries. -.Ip "\fB\-Wwrite-strings\fR" 4 -.IX Item "-Wwrite-strings" -When compiling C, give string constants the type \f(CW\*(C`const -char[\f(CIlength\f(CW]\*(C'\fR so that -copying the address of one into a non-\f(CW\*(C`const\*(C'\fR \f(CW\*(C`char *\*(C'\fR -pointer will get a warning; when compiling \*(C+, warn about the -deprecated conversion from string constants to \f(CW\*(C`char *\*(C'\fR. -These warnings will help you find at -compile time code that can try to write into a string constant, but -only if you have been very careful about using \f(CW\*(C`const\*(C'\fR in -declarations and prototypes. Otherwise, it will just be a nuisance; -this is why we did not make \fB\-Wall\fR request these warnings. -.Ip "\fB\-Wconversion\fR" 4 -.IX Item "-Wconversion" -Warn if a prototype causes a type conversion that is different from what -would happen to the same argument in the absence of a prototype. This -includes conversions of fixed point to floating and vice versa, and -conversions changing the width or signedness of a fixed point argument -except when the same as the default promotion. -.Sp -Also, warn if a negative integer constant expression is implicitly -converted to an unsigned type. For example, warn about the assignment -\&\f(CW\*(C`x = \-1\*(C'\fR if \f(CW\*(C`x\*(C'\fR is unsigned. But do not warn about explicit -casts like \f(CW\*(C`(unsigned) \-1\*(C'\fR. -.Ip "\fB\-Wsign-compare\fR" 4 -.IX Item "-Wsign-compare" -Warn when a comparison between signed and unsigned values could produce -an incorrect result when the signed value is converted to unsigned. -This warning is also enabled by \fB\-W\fR; to get the other warnings -of \fB\-W\fR without this warning, use \fB\-W \-Wno-sign-compare\fR. -.Ip "\fB\-Waggregate-return\fR" 4 -.IX Item "-Waggregate-return" -Warn if any functions that return structures or unions are defined or -called. (In languages where you can return an array, this also elicits -a warning.) -.Ip "\fB\-Wstrict-prototypes\fR (C only)" 4 -.IX Item "-Wstrict-prototypes (C only)" -Warn if a function is declared or defined without specifying the -argument types. (An old-style function definition is permitted without -a warning if preceded by a declaration which specifies the argument -types.) -.Ip "\fB\-Wmissing-prototypes\fR (C only)" 4 -.IX Item "-Wmissing-prototypes (C only)" -Warn if a global function is defined without a previous prototype -declaration. This warning is issued even if the definition itself -provides a prototype. The aim is to detect global functions that fail -to be declared in header files. -.Ip "\fB\-Wmissing-declarations\fR" 4 -.IX Item "-Wmissing-declarations" -Warn if a global function is defined without a previous declaration. -Do so even if the definition itself provides a prototype. -Use this option to detect global functions that are not declared in -header files. -.Ip "\fB\-Wmissing-noreturn\fR" 4 -.IX Item "-Wmissing-noreturn" -Warn about functions which might be candidates for attribute \f(CW\*(C`noreturn\*(C'\fR. -Note these are only possible candidates, not absolute ones. Care should -be taken to manually verify functions actually do not ever return before -adding the \f(CW\*(C`noreturn\*(C'\fR attribute, otherwise subtle code generation -bugs could be introduced. You will not get a warning for \f(CW\*(C`main\*(C'\fR in -hosted C environments. -.Ip "\fB\-Wmissing-format-attribute\fR" 4 -.IX Item "-Wmissing-format-attribute" -If \fB\-Wformat\fR is enabled, also warn about functions which might be -candidates for \f(CW\*(C`format\*(C'\fR attributes. Note these are only possible -candidates, not absolute ones. \s-1GCC\s0 will guess that \f(CW\*(C`format\*(C'\fR -attributes might be appropriate for any function that calls a function -like \f(CW\*(C`vprintf\*(C'\fR or \f(CW\*(C`vscanf\*(C'\fR, but this might not always be the -case, and some functions for which \f(CW\*(C`format\*(C'\fR attributes are -appropriate may not be detected. This option has no effect unless -\&\fB\-Wformat\fR is enabled (possibly by \fB\-Wall\fR). -.Ip "\fB\-Wno-deprecated-declarations\fR" 4 -.IX Item "-Wno-deprecated-declarations" -Do not warn about uses of functions, variables, and types marked as -deprecated by using the \f(CW\*(C`deprecated\*(C'\fR attribute. -(@pxref{Function Attributes}, \f(CW@pxref\fR{Variable Attributes}, -\&\f(CW@pxref\fR{Type Attributes}.) -.Ip "\fB\-Wpacked\fR" 4 -.IX Item "-Wpacked" -Warn if a structure is given the packed attribute, but the packed -attribute has no effect on the layout or size of the structure. -Such structures may be mis-aligned for little benefit. For -instance, in this code, the variable \f(CW\*(C`f.x\*(C'\fR in \f(CW\*(C`struct bar\*(C'\fR -will be misaligned even though \f(CW\*(C`struct bar\*(C'\fR does not itself -have the packed attribute: -.Sp -.Vb 8 -\& struct foo { -\& int x; -\& char a, b, c, d; -\& } __attribute__((packed)); -\& struct bar { -\& char z; -\& struct foo f; -\& }; -.Ve -.Ip "\fB\-Wpadded\fR" 4 -.IX Item "-Wpadded" -Warn if padding is included in a structure, either to align an element -of the structure or to align the whole structure. Sometimes when this -happens it is possible to rearrange the fields of the structure to -reduce the padding and so make the structure smaller. -.Ip "\fB\-Wredundant-decls\fR" 4 -.IX Item "-Wredundant-decls" -Warn if anything is declared more than once in the same scope, even in -cases where multiple declaration is valid and changes nothing. -.Ip "\fB\-Wnested-externs\fR (C only)" 4 -.IX Item "-Wnested-externs (C only)" -Warn if an \f(CW\*(C`extern\*(C'\fR declaration is encountered within a function. -.Ip "\fB\-Wunreachable-code\fR" 4 -.IX Item "-Wunreachable-code" -Warn if the compiler detects that code will never be executed. -.Sp -This option is intended to warn when the compiler detects that at -least a whole line of source code will never be executed, because -some condition is never satisfied or because it is after a -procedure that never returns. -.Sp -It is possible for this option to produce a warning even though there -are circumstances under which part of the affected line can be executed, -so care should be taken when removing apparently-unreachable code. -.Sp -For instance, when a function is inlined, a warning may mean that the -line is unreachable in only one inlined copy of the function. -.Sp -This option is not made part of \fB\-Wall\fR because in a debugging -version of a program there is often substantial code which checks -correct functioning of the program and is, hopefully, unreachable -because the program does work. Another common use of unreachable -code is to provide behavior which is selectable at compile-time. -.Ip "\fB\-Winline\fR" 4 -.IX Item "-Winline" -Warn if a function can not be inlined and it was declared as inline. -.Ip "\fB\-Wlong-long\fR" 4 -.IX Item "-Wlong-long" -Warn if \fBlong long\fR type is used. This is default. To inhibit -the warning messages, use \fB\-Wno-long-long\fR. Flags -\&\fB\-Wlong-long\fR and \fB\-Wno-long-long\fR are taken into account -only when \fB\-pedantic\fR flag is used. -.Ip "\fB\-Wdisabled-optimization\fR" 4 -.IX Item "-Wdisabled-optimization" -Warn if a requested optimization pass is disabled. This warning does -not generally indicate that there is anything wrong with your code; it -merely indicates that \s-1GCC\s0's optimizers were unable to handle the code -effectively. Often, the problem is that your code is too big or too -complex; \s-1GCC\s0 will refuse to optimize programs when the optimization -itself is likely to take inordinate amounts of time. -.Ip "\fB\-Werror\fR" 4 -.IX Item "-Werror" -Make all warnings into errors. -.Sh "Options for Debugging Your Program or \s-1GCC\s0" -.IX Subsection "Options for Debugging Your Program or GCC" -\&\s-1GCC\s0 has various special options that are used for debugging -either your program or \s-1GCC:\s0 -.Ip "\fB\-g\fR" 4 -.IX Item "-g" -Produce debugging information in the operating system's native format -(stabs, \s-1COFF\s0, \s-1XCOFF\s0, or \s-1DWARF\s0). \s-1GDB\s0 can work with this debugging -information. -.Sp -On most systems that use stabs format, \fB\-g\fR enables use of extra -debugging information that only \s-1GDB\s0 can use; this extra information -makes debugging work better in \s-1GDB\s0 but will probably make other debuggers -crash or -refuse to read the program. If you want to control for certain whether -to generate the extra information, use \fB\-gstabs+\fR, \fB\-gstabs\fR, -\&\fB\-gxcoff+\fR, \fB\-gxcoff\fR, \fB\-gdwarf-1+\fR, \fB\-gdwarf-1\fR, -or \fB\-gvms\fR (see below). -.Sp -Unlike most other C compilers, \s-1GCC\s0 allows you to use \fB\-g\fR with -\&\fB\-O\fR. The shortcuts taken by optimized code may occasionally -produce surprising results: some variables you declared may not exist -at all; flow of control may briefly move where you did not expect it; -some statements may not be executed because they compute constant -results or their values were already at hand; some statements may -execute in different places because they were moved out of loops. -.Sp -Nevertheless it proves possible to debug optimized output. This makes -it reasonable to use the optimizer for programs that might have bugs. -.Sp -The following options are useful when \s-1GCC\s0 is generated with the -capability for more than one debugging format. -.Ip "\fB\-ggdb\fR" 4 -.IX Item "-ggdb" -Produce debugging information for use by \s-1GDB\s0. This means to use the -most expressive format available (\s-1DWARF\s0 2, stabs, or the native format -if neither of those are supported), including \s-1GDB\s0 extensions if at all -possible. -.Ip "\fB\-gstabs\fR" 4 -.IX Item "-gstabs" -Produce debugging information in stabs format (if that is supported), -without \s-1GDB\s0 extensions. This is the format used by \s-1DBX\s0 on most \s-1BSD\s0 -systems. On \s-1MIPS\s0, Alpha and System V Release 4 systems this option -produces stabs debugging output which is not understood by \s-1DBX\s0 or \s-1SDB\s0. -On System V Release 4 systems this option requires the \s-1GNU\s0 assembler. -.Ip "\fB\-gstabs+\fR" 4 -.IX Item "-gstabs+" -Produce debugging information in stabs format (if that is supported), -using \s-1GNU\s0 extensions understood only by the \s-1GNU\s0 debugger (\s-1GDB\s0). The -use of these extensions is likely to make other debuggers crash or -refuse to read the program. -.Ip "\fB\-gcoff\fR" 4 -.IX Item "-gcoff" -Produce debugging information in \s-1COFF\s0 format (if that is supported). -This is the format used by \s-1SDB\s0 on most System V systems prior to -System V Release 4. -.Ip "\fB\-gxcoff\fR" 4 -.IX Item "-gxcoff" -Produce debugging information in \s-1XCOFF\s0 format (if that is supported). -This is the format used by the \s-1DBX\s0 debugger on \s-1IBM\s0 \s-1RS/6000\s0 systems. -.Ip "\fB\-gxcoff+\fR" 4 -.IX Item "-gxcoff+" -Produce debugging information in \s-1XCOFF\s0 format (if that is supported), -using \s-1GNU\s0 extensions understood only by the \s-1GNU\s0 debugger (\s-1GDB\s0). The -use of these extensions is likely to make other debuggers crash or -refuse to read the program, and may cause assemblers other than the \s-1GNU\s0 -assembler (\s-1GAS\s0) to fail with an error. -.Ip "\fB\-gdwarf\fR" 4 -.IX Item "-gdwarf" -Produce debugging information in \s-1DWARF\s0 version 1 format (if that is -supported). This is the format used by \s-1SDB\s0 on most System V Release 4 -systems. -.Ip "\fB\-gdwarf+\fR" 4 -.IX Item "-gdwarf+" -Produce debugging information in \s-1DWARF\s0 version 1 format (if that is -supported), using \s-1GNU\s0 extensions understood only by the \s-1GNU\s0 debugger -(\s-1GDB\s0). The use of these extensions is likely to make other debuggers -crash or refuse to read the program. -.Ip "\fB\-gdwarf-2\fR" 4 -.IX Item "-gdwarf-2" -Produce debugging information in \s-1DWARF\s0 version 2 format (if that is -supported). This is the format used by \s-1DBX\s0 on \s-1IRIX\s0 6. -.Ip "\fB\-gvms\fR" 4 -.IX Item "-gvms" -Produce debugging information in \s-1VMS\s0 debug format (if that is -supported). This is the format used by \s-1DEBUG\s0 on \s-1VMS\s0 systems. -.Ip "\fB\-g\fR\fIlevel\fR" 4 -.IX Item "-glevel" -.PD 0 -.Ip "\fB\-ggdb\fR\fIlevel\fR" 4 -.IX Item "-ggdblevel" -.Ip "\fB\-gstabs\fR\fIlevel\fR" 4 -.IX Item "-gstabslevel" -.Ip "\fB\-gcoff\fR\fIlevel\fR" 4 -.IX Item "-gcofflevel" -.Ip "\fB\-gxcoff\fR\fIlevel\fR" 4 -.IX Item "-gxcofflevel" -.Ip "\fB\-gvms\fR\fIlevel\fR" 4 -.IX Item "-gvmslevel" -.PD -Request debugging information and also use \fIlevel\fR to specify how -much information. The default level is 2. -.Sp -Level 1 produces minimal information, enough for making backtraces in -parts of the program that you don't plan to debug. This includes -descriptions of functions and external variables, but no information -about local variables and no line numbers. -.Sp -Level 3 includes extra information, such as all the macro definitions -present in the program. Some debuggers support macro expansion when -you use \fB\-g3\fR. -.Sp -Note that in order to avoid confusion between \s-1DWARF1\s0 debug level 2, -and \s-1DWARF2\s0, neither \fB\-gdwarf\fR nor \fB\-gdwarf-2\fR accept -a concatenated debug level. Instead use an additional \fB\-g\fR\fIlevel\fR -option to change the debug level for \s-1DWARF1\s0 or \s-1DWARF2\s0. -.Ip "\fB\-p\fR" 4 -.IX Item "-p" -Generate extra code to write profile information suitable for the -analysis program \f(CW\*(C`prof\*(C'\fR. You must use this option when compiling -the source files you want data about, and you must also use it when -linking. -.Ip "\fB\-pg\fR" 4 -.IX Item "-pg" -Generate extra code to write profile information suitable for the -analysis program \f(CW\*(C`gprof\*(C'\fR. You must use this option when compiling -the source files you want data about, and you must also use it when -linking. -.Ip "\fB\-Q\fR" 4 -.IX Item "-Q" -Makes the compiler print out each function name as it is compiled, and -print some statistics about each pass when it finishes. -.Ip "\fB\-ftime-report\fR" 4 -.IX Item "-ftime-report" -Makes the compiler print some statistics about the time consumed by each -pass when it finishes. -.Ip "\fB\-fmem-report\fR" 4 -.IX Item "-fmem-report" -Makes the compiler print some statistics about permanent memory -allocation when it finishes. -.Ip "\fB\-fprofile-arcs\fR" 4 -.IX Item "-fprofile-arcs" -Instrument \fIarcs\fR during compilation to generate coverage data -or for profile-directed block ordering. During execution the program -records how many times each branch is executed and how many times it is -taken. When the compiled program exits it saves this data to a file -called \fI\fIsourcename\fI.da\fR for each source file. -.Sp -For profile-directed block ordering, compile the program with -\&\fB\-fprofile-arcs\fR plus optimization and code generation options, -generate the arc profile information by running the program on a -selected workload, and then compile the program again with the same -optimization and code generation options plus -\&\fB\-fbranch-probabilities\fR. -.Sp -The other use of \fB\-fprofile-arcs\fR is for use with \f(CW\*(C`gcov\*(C'\fR, -when it is used with the \fB\-ftest-coverage\fR option. -.Sp -With \fB\-fprofile-arcs\fR, for each function of your program \s-1GCC\s0 -creates a program flow graph, then finds a spanning tree for the graph. -Only arcs that are not on the spanning tree have to be instrumented: the -compiler adds code to count the number of times that these arcs are -executed. When an arc is the only exit or only entrance to a block, the -instrumentation code can be added to the block; otherwise, a new basic -block must be created to hold the instrumentation code. -.Ip "\fB\-ftest-coverage\fR" 4 -.IX Item "-ftest-coverage" -Create data files for the \fBgcov\fR code-coverage utility. -The data file names begin with the name of your source file: -.RS 4 -.Ip "\fIsourcename\fR\fB.bb\fR" 4 -.IX Item "sourcename.bb" -A mapping from basic blocks to line numbers, which \f(CW\*(C`gcov\*(C'\fR uses to -associate basic block execution counts with line numbers. -.Ip "\fIsourcename\fR\fB.bbg\fR" 4 -.IX Item "sourcename.bbg" -A list of all arcs in the program flow graph. This allows \f(CW\*(C`gcov\*(C'\fR -to reconstruct the program flow graph, so that it can compute all basic -block and arc execution counts from the information in the -\&\f(CW\*(C`\f(CIsourcename\f(CW.da\*(C'\fR file. -.RE -.RS 4 -.Sp -Use \fB\-ftest-coverage\fR with \fB\-fprofile-arcs\fR; the latter -option adds instrumentation to the program, which then writes -execution counts to another data file: -.RS 4 -.RE -.Ip "\fIsourcename\fR\fB.da\fR" 4 -.IX Item "sourcename.da" -Runtime arc execution counts, used in conjunction with the arc -information in the file \f(CW\*(C`\f(CIsourcename\f(CW.bbg\*(C'\fR. -.RE -.RS 4 -.Sp -Coverage data will map better to the source files if -\&\fB\-ftest-coverage\fR is used without optimization. -.RE -.Ip "\fB\-d\fR\fIletters\fR" 4 -.IX Item "-dletters" -Says to make debugging dumps during compilation at times specified by -\&\fIletters\fR. This is used for debugging the compiler. The file names -for most of the dumps are made by appending a pass number and a word to -the source file name (e.g. \fIfoo.c.00.rtl\fR or \fIfoo.c.01.sibling\fR). -Here are the possible letters for use in \fIletters\fR, and their meanings: -.RS 4 -.Ip "\fBA\fR" 4 -.IX Item "A" -Annotate the assembler output with miscellaneous debugging information. -.Ip "\fBb\fR" 4 -.IX Item "b" -Dump after computing branch probabilities, to \fI\fIfile\fI.14.bp\fR. -.Ip "\fBB\fR" 4 -.IX Item "B" -Dump after block reordering, to \fI\fIfile\fI.29.bbro\fR. -.Ip "\fBc\fR" 4 -.IX Item "c" -Dump after instruction combination, to the file \fI\fIfile\fI.16.combine\fR. -.Ip "\fBC\fR" 4 -.IX Item "C" -Dump after the first if conversion, to the file \fI\fIfile\fI.17.ce\fR. -.Ip "\fBd\fR" 4 -.IX Item "d" -Dump after delayed branch scheduling, to \fI\fIfile\fI.31.dbr\fR. -.Ip "\fBD\fR" 4 -.IX Item "D" -Dump all macro definitions, at the end of preprocessing, in addition to -normal output. -.Ip "\fBe\fR" 4 -.IX Item "e" -Dump after \s-1SSA\s0 optimizations, to \fI\fIfile\fI.04.ssa\fR and -\&\fI\fIfile\fI.07.ussa\fR. -.Ip "\fBE\fR" 4 -.IX Item "E" -Dump after the second if conversion, to \fI\fIfile\fI.26.ce2\fR. -.Ip "\fBf\fR" 4 -.IX Item "f" -Dump after life analysis, to \fI\fIfile\fI.15.life\fR. -.Ip "\fBF\fR" 4 -.IX Item "F" -Dump after purging \f(CW\*(C`ADDRESSOF\*(C'\fR codes, to \fI\fIfile\fI.09.addressof\fR. -.Ip "\fBg\fR" 4 -.IX Item "g" -Dump after global register allocation, to \fI\fIfile\fI.21.greg\fR. -.Ip "\fBh\fR" 4 -.IX Item "h" -Dump after finalization of \s-1EH\s0 handling code, to \fI\fIfile\fI.02.eh\fR. -.Ip "\fBk\fR" 4 -.IX Item "k" -Dump after reg-to-stack conversion, to \fI\fIfile\fI.28.stack\fR. -.Ip "\fBo\fR" 4 -.IX Item "o" -Dump after post-reload optimizations, to \fI\fIfile\fI.22.postreload\fR. -.Ip "\fBG\fR" 4 -.IX Item "G" -Dump after \s-1GCSE\s0, to \fI\fIfile\fI.10.gcse\fR. -.Ip "\fBi\fR" 4 -.IX Item "i" -Dump after sibling call optimizations, to \fI\fIfile\fI.01.sibling\fR. -.Ip "\fBj\fR" 4 -.IX Item "j" -Dump after the first jump optimization, to \fI\fIfile\fI.03.jump\fR. -.Ip "\fBk\fR" 4 -.IX Item "k" -Dump after conversion from registers to stack, to \fI\fIfile\fI.32.stack\fR. -.Ip "\fBl\fR" 4 -.IX Item "l" -Dump after local register allocation, to \fI\fIfile\fI.20.lreg\fR. -.Ip "\fBL\fR" 4 -.IX Item "L" -Dump after loop optimization, to \fI\fIfile\fI.11.loop\fR. -.Ip "\fBM\fR" 4 -.IX Item "M" -Dump after performing the machine dependent reorganisation pass, to -\&\fI\fIfile\fI.30.mach\fR. -.Ip "\fBn\fR" 4 -.IX Item "n" -Dump after register renumbering, to \fI\fIfile\fI.25.rnreg\fR. -.Ip "\fBN\fR" 4 -.IX Item "N" -Dump after the register move pass, to \fI\fIfile\fI.18.regmove\fR. -.Ip "\fBr\fR" 4 -.IX Item "r" -Dump after \s-1RTL\s0 generation, to \fI\fIfile\fI.00.rtl\fR. -.Ip "\fBR\fR" 4 -.IX Item "R" -Dump after the second scheduling pass, to \fI\fIfile\fI.27.sched2\fR. -.Ip "\fBs\fR" 4 -.IX Item "s" -Dump after \s-1CSE\s0 (including the jump optimization that sometimes follows -\&\s-1CSE\s0), to \fI\fIfile\fI.08.cse\fR. -.Ip "\fBS\fR" 4 -.IX Item "S" -Dump after the first scheduling pass, to \fI\fIfile\fI.19.sched\fR. -.Ip "\fBt\fR" 4 -.IX Item "t" -Dump after the second \s-1CSE\s0 pass (including the jump optimization that -sometimes follows \s-1CSE\s0), to \fI\fIfile\fI.12.cse2\fR. -.Ip "\fBw\fR" 4 -.IX Item "w" -Dump after the second flow pass, to \fI\fIfile\fI.23.flow2\fR. -.Ip "\fBX\fR" 4 -.IX Item "X" -Dump after \s-1SSA\s0 dead code elimination, to \fI\fIfile\fI.06.ssadce\fR. -.Ip "\fBz\fR" 4 -.IX Item "z" -Dump after the peephole pass, to \fI\fIfile\fI.24.peephole2\fR. -.Ip "\fBa\fR" 4 -.IX Item "a" -Produce all the dumps listed above. -.Ip "\fBm\fR" 4 -.IX Item "m" -Print statistics on memory usage, at the end of the run, to -standard error. -.Ip "\fBp\fR" 4 -.IX Item "p" -Annotate the assembler output with a comment indicating which -pattern and alternative was used. The length of each instruction is -also printed. -.Ip "\fBP\fR" 4 -.IX Item "P" -Dump the \s-1RTL\s0 in the assembler output as a comment before each instruction. -Also turns on \fB\-dp\fR annotation. -.Ip "\fBv\fR" 4 -.IX Item "v" -For each of the other indicated dump files (except for -\&\fI\fIfile\fI.00.rtl\fR), dump a representation of the control flow graph -suitable for viewing with \s-1VCG\s0 to \fI\fIfile\fI.\fIpass\fI.vcg\fR. -.Ip "\fBx\fR" 4 -.IX Item "x" -Just generate \s-1RTL\s0 for a function instead of compiling it. Usually used -with \fBr\fR. -.Ip "\fBy\fR" 4 -.IX Item "y" -Dump debugging information during parsing, to standard error. -.RE -.RS 4 -.RE -.Ip "\fB\-fdump-unnumbered\fR" 4 -.IX Item "-fdump-unnumbered" -When doing debugging dumps (see \fB\-d\fR option above), suppress instruction -numbers and line number note output. This makes it more feasible to -use diff on debugging dumps for compiler invocations with different -options, in particular with and without \fB\-g\fR. -.Ip "\fB\-fdump-translation-unit\fR (C and \*(C+ only)" 4 -.IX Item "-fdump-translation-unit (C and only)" -.PD 0 -.Ip "\fB\-fdump-translation-unit-\fR\fIoptions\fR\fB \fR(C and \*(C+ only)" 4 -.IX Item "-fdump-translation-unit-options (C and only)" -.PD -Dump a representation of the tree structure for the entire translation -unit to a file. The file name is made by appending \fI.tu\fR to the -source file name. If the \fB-\fR\fIoptions\fR form is used, \fIoptions\fR -controls the details of the dump as described for the -\&\fB\-fdump-tree\fR options. -.Ip "\fB\-fdump-class-hierarchy\fR (\*(C+ only)" 4 -.IX Item "-fdump-class-hierarchy ( only)" -.PD 0 -.Ip "\fB\-fdump-class-hierarchy-\fR\fIoptions\fR\fB \fR(\*(C+ only)" 4 -.IX Item "-fdump-class-hierarchy-options ( only)" -.PD -Dump a representation of each class's hierarchy and virtual function -table layout to a file. The file name is made by appending \fI.class\fR -to the source file name. If the \fB-\fR\fIoptions\fR form is used, -\&\fIoptions\fR controls the details of the dump as described for the -\&\fB\-fdump-tree\fR options. -.Ip "\fB\-fdump-tree-\fR\fIswitch\fR\fB \fR(\*(C+ only)" 4 -.IX Item "-fdump-tree-switch ( only)" -.PD 0 -.Ip "\fB\-fdump-tree-\fR\fIswitch\fR\fB-\fR\fIoptions\fR\fB \fR(\*(C+ only)" 4 -.IX Item "-fdump-tree-switch-options ( only)" -.PD -Control the dumping at various stages of processing the intermediate -language tree to a file. The file name is generated by appending a switch -specific suffix to the source file name. If the \fB-\fR\fIoptions\fR -form is used, \fIoptions\fR is a list of \fB-\fR separated options that -control the details of the dump. Not all options are applicable to all -dumps, those which are not meaningful will be ignored. The following -options are available -.RS 4 -.Ip "\fBaddress\fR" 4 -.IX Item "address" -Print the address of each node. Usually this is not meaningful as it -changes according to the environment and source file. Its primary use -is for tying up a dump file with a debug environment. -.Ip "\fBslim\fR" 4 -.IX Item "slim" -Inhibit dumping of members of a scope or body of a function merely -because that scope has been reached. Only dump such items when they -are directly reachable by some other path. -.Ip "\fBall\fR" 4 -.IX Item "all" -Turn on all options. -.RE -.RS 4 -.Sp -The following tree dumps are possible: -.RS 4 -.RE -.Ip "\fBoriginal\fR" 4 -.IX Item "original" -Dump before any tree based optimization, to \fI\fIfile\fI.original\fR. -.Ip "\fBoptimized\fR" 4 -.IX Item "optimized" -Dump after all tree based optimization, to \fI\fIfile\fI.optimized\fR. -.Ip "\fBinlined\fR" 4 -.IX Item "inlined" -Dump after function inlining, to \fI\fIfile\fI.inlined\fR. -.RE -.RS 4 -.RE -.Ip "\fB\-fsched-verbose=\fR\fIn\fR" 4 -.IX Item "-fsched-verbose=n" -On targets that use instruction scheduling, this option controls the -amount of debugging output the scheduler prints. This information is -written to standard error, unless \fB\-dS\fR or \fB\-dR\fR is -specified, in which case it is output to the usual dump -listing file, \fI.sched\fR or \fI.sched2\fR respectively. However -for \fIn\fR greater than nine, the output is always printed to standard -error. -.Sp -For \fIn\fR greater than zero, \fB\-fsched-verbose\fR outputs the -same information as \fB\-dRS\fR. For \fIn\fR greater than one, it -also output basic block probabilities, detailed ready list information -and unit/insn info. For \fIn\fR greater than two, it includes \s-1RTL\s0 -at abort point, control-flow and regions info. And for \fIn\fR over -four, \fB\-fsched-verbose\fR also includes dependence info. -.Ip "\fB\-fpretend-float\fR" 4 -.IX Item "-fpretend-float" -When running a cross-compiler, pretend that the target machine uses the -same floating point format as the host machine. This causes incorrect -output of the actual floating constants, but the actual instruction -sequence will probably be the same as \s-1GCC\s0 would make when running on -the target machine. -.Ip "\fB\-save-temps\fR" 4 -.IX Item "-save-temps" -Store the usual ``temporary'' intermediate files permanently; place them -in the current directory and name them based on the source file. Thus, -compiling \fIfoo.c\fR with \fB\-c \-save-temps\fR would produce files -\&\fIfoo.i\fR and \fIfoo.s\fR, as well as \fIfoo.o\fR. This creates a -preprocessed \fIfoo.i\fR output file even though the compiler now -normally uses an integrated preprocessor. -.Ip "\fB\-time\fR" 4 -.IX Item "-time" -Report the \s-1CPU\s0 time taken by each subprocess in the compilation -sequence. For C source files, this is the compiler proper and assembler -(plus the linker if linking is done). The output looks like this: -.Sp -.Vb 2 -\& # cc1 0.12 0.01 -\& # as 0.00 0.01 -.Ve -The first number on each line is the ``user time,'' that is time spent -executing the program itself. The second number is ``system time,'' -time spent executing operating system routines on behalf of the program. -Both numbers are in seconds. -.Ip "\fB\-print-file-name=\fR\fIlibrary\fR" 4 -.IX Item "-print-file-name=library" -Print the full absolute name of the library file \fIlibrary\fR that -would be used when linking\-\-\-and don't do anything else. With this -option, \s-1GCC\s0 does not compile or link anything; it just prints the -file name. -.Ip "\fB\-print-multi-directory\fR" 4 -.IX Item "-print-multi-directory" -Print the directory name corresponding to the multilib selected by any -other switches present in the command line. This directory is supposed -to exist in \fB\s-1GCC_EXEC_PREFIX\s0\fR. -.Ip "\fB\-print-multi-lib\fR" 4 -.IX Item "-print-multi-lib" -Print the mapping from multilib directory names to compiler switches -that enable them. The directory name is separated from the switches by -\&\fB;\fR, and each switch starts with an \fB@} instead of the -\&\f(CB@samp\fB{-\fR, without spaces between multiple switches. This is supposed to -ease shell-processing. -.Ip "\fB\-print-prog-name=\fR\fIprogram\fR" 4 -.IX Item "-print-prog-name=program" -Like \fB\-print-file-name\fR, but searches for a program such as \fBcpp\fR. -.Ip "\fB\-print-libgcc-file-name\fR" 4 -.IX Item "-print-libgcc-file-name" -Same as \fB\-print-file-name=libgcc.a\fR. -.Sp -This is useful when you use \fB\-nostdlib\fR or \fB\-nodefaultlibs\fR -but you do want to link with \fIlibgcc.a\fR. You can do -.Sp -.Vb 1 -\& gcc -nostdlib <files>... `gcc -print-libgcc-file-name` -.Ve -.Ip "\fB\-print-search-dirs\fR" 4 -.IX Item "-print-search-dirs" -Print the name of the configured installation directory and a list of -program and library directories gcc will search\-\-\-and don't do anything else. -.Sp -This is useful when gcc prints the error message -\&\fBinstallation problem, cannot exec cpp0: No such file or directory\fR. -To resolve this you either need to put \fIcpp0\fR and the other compiler -components where gcc expects to find them, or you can set the environment -variable \fB\s-1GCC_EXEC_PREFIX\s0\fR to the directory where you installed them. -Don't forget the trailing '/'. -.Ip "\fB\-dumpmachine\fR" 4 -.IX Item "-dumpmachine" -Print the compiler's target machine (for example, -\&\fBi686\-pc-linux-gnu\fR)\-\-\-and don't do anything else. -.Ip "\fB\-dumpversion\fR" 4 -.IX Item "-dumpversion" -Print the compiler version (for example, \fB3.0\fR)\-\-\-and don't do -anything else. -.Ip "\fB\-dumpspecs\fR" 4 -.IX Item "-dumpspecs" -Print the compiler's built-in specs\-\-\-and don't do anything else. (This -is used when \s-1GCC\s0 itself is being built.) -.Sh "Options That Control Optimization" -.IX Subsection "Options That Control Optimization" -These options control various sorts of optimizations: -.Ip "\fB\-O\fR" 4 -.IX Item "-O" -.PD 0 -.Ip "\fB\-O1\fR" 4 -.IX Item "-O1" -.PD -Optimize. Optimizing compilation takes somewhat more time, and a lot -more memory for a large function. -.Sp -Without \fB\-O\fR, the compiler's goal is to reduce the cost of -compilation and to make debugging produce the expected results. -Statements are independent: if you stop the program with a breakpoint -between statements, you can then assign a new value to any variable or -change the program counter to any other statement in the function and -get exactly the results you would expect from the source code. -.Sp -With \fB\-O\fR, the compiler tries to reduce code size and execution -time, without performing any optimizations that take a great deal of -compilation time. -.Ip "\fB\-O2\fR" 4 -.IX Item "-O2" -Optimize even more. \s-1GCC\s0 performs nearly all supported optimizations -that do not involve a space-speed tradeoff. The compiler does not -perform loop unrolling or function inlining when you specify \fB\-O2\fR. -As compared to \fB\-O\fR, this option increases both compilation time -and the performance of the generated code. -.Sp -\&\fB\-O2\fR turns on all optional optimizations except for loop unrolling, -function inlining, and register renaming. It also turns on the -\&\fB\-fforce-mem\fR option on all machines and frame pointer elimination -on machines where doing so does not interfere with debugging. -.Sp -Please note the warning under \fB\-fgcse\fR about -invoking \fB\-O2\fR on programs that use computed gotos. -.Ip "\fB\-O3\fR" 4 -.IX Item "-O3" -Optimize yet more. \fB\-O3\fR turns on all optimizations specified by -\&\fB\-O2\fR and also turns on the \fB\-finline-functions\fR and -\&\fB\-frename-registers\fR options. -.Ip "\fB\-O0\fR" 4 -.IX Item "-O0" -Do not optimize. -.Ip "\fB\-Os\fR" 4 -.IX Item "-Os" -Optimize for size. \fB\-Os\fR enables all \fB\-O2\fR optimizations that -do not typically increase code size. It also performs further -optimizations designed to reduce code size. -.Sp -If you use multiple \fB\-O\fR options, with or without level numbers, -the last such option is the one that is effective. -.PP -Options of the form \fB\-f\fR\fIflag\fR specify machine-independent -flags. Most flags have both positive and negative forms; the negative -form of \fB\-ffoo\fR would be \fB\-fno-foo\fR. In the table below, -only one of the forms is listed\-\-\-the one which is not the default. -You can figure out the other form by either removing \fBno-\fR or -adding it. -.Ip "\fB\-ffloat-store\fR" 4 -.IX Item "-ffloat-store" -Do not store floating point variables in registers, and inhibit other -options that might change whether a floating point value is taken from a -register or memory. -.Sp -This option prevents undesirable excess precision on machines such as -the 68000 where the floating registers (of the 68881) keep more -precision than a \f(CW\*(C`double\*(C'\fR is supposed to have. Similarly for the -x86 architecture. For most programs, the excess precision does only -good, but a few programs rely on the precise definition of \s-1IEEE\s0 floating -point. Use \fB\-ffloat-store\fR for such programs, after modifying -them to store all pertinent intermediate computations into variables. -.Ip "\fB\-fno-default-inline\fR" 4 -.IX Item "-fno-default-inline" -Do not make member functions inline by default merely because they are -defined inside the class scope (\*(C+ only). Otherwise, when you specify -\&\fB\-O\fR, member functions defined inside class scope are compiled -inline by default; i.e., you don't need to add \fBinline\fR in front of -the member function name. -.Ip "\fB\-fno-defer-pop\fR" 4 -.IX Item "-fno-defer-pop" -Always pop the arguments to each function call as soon as that function -returns. For machines which must pop arguments after a function call, -the compiler normally lets arguments accumulate on the stack for several -function calls and pops them all at once. -.Ip "\fB\-fforce-mem\fR" 4 -.IX Item "-fforce-mem" -Force memory operands to be copied into registers before doing -arithmetic on them. This produces better code by making all memory -references potential common subexpressions. When they are not common -subexpressions, instruction combination should eliminate the separate -register-load. The \fB\-O2\fR option turns on this option. -.Ip "\fB\-fforce-addr\fR" 4 -.IX Item "-fforce-addr" -Force memory address constants to be copied into registers before -doing arithmetic on them. This may produce better code just as -\&\fB\-fforce-mem\fR may. -.Ip "\fB\-fomit-frame-pointer\fR" 4 -.IX Item "-fomit-frame-pointer" -Don't keep the frame pointer in a register for functions that -don't need one. This avoids the instructions to save, set up and -restore frame pointers; it also makes an extra register available -in many functions. \fBIt also makes debugging impossible on -some machines.\fR -.Sp -On some machines, such as the \s-1VAX\s0, this flag has no effect, because -the standard calling sequence automatically handles the frame pointer -and nothing is saved by pretending it doesn't exist. The -machine-description macro \f(CW\*(C`FRAME_POINTER_REQUIRED\*(C'\fR controls -whether a target machine supports this flag. -.Ip "\fB\-foptimize-sibling-calls\fR" 4 -.IX Item "-foptimize-sibling-calls" -Optimize sibling and tail recursive calls. -.Ip "\fB\-ftrapv\fR" 4 -.IX Item "-ftrapv" -This option generates traps for signed overflow on addition, subtraction, -multiplication operations. -.Ip "\fB\-fno-inline\fR" 4 -.IX Item "-fno-inline" -Don't pay attention to the \f(CW\*(C`inline\*(C'\fR keyword. Normally this option -is used to keep the compiler from expanding any functions inline. -Note that if you are not optimizing, no functions can be expanded inline. -.Ip "\fB\-finline-functions\fR" 4 -.IX Item "-finline-functions" -Integrate all simple functions into their callers. The compiler -heuristically decides which functions are simple enough to be worth -integrating in this way. -.Sp -If all calls to a given function are integrated, and the function is -declared \f(CW\*(C`static\*(C'\fR, then the function is normally not output as -assembler code in its own right. -.Ip "\fB\-finline-limit=\fR\fIn\fR" 4 -.IX Item "-finline-limit=n" -By default, gcc limits the size of functions that can be inlined. This flag -allows the control of this limit for functions that are explicitly marked as -inline (ie marked with the inline keyword or defined within the class -definition in c++). \fIn\fR is the size of functions that can be inlined in -number of pseudo instructions (not counting parameter handling). The default -value of \fIn\fR is 600. -Increasing this value can result in more inlined code at -the cost of compilation time and memory consumption. Decreasing usually makes -the compilation faster and less code will be inlined (which presumably -means slower programs). This option is particularly useful for programs that -use inlining heavily such as those based on recursive templates with \*(C+. -.Sp -\&\fINote:\fR pseudo instruction represents, in this particular context, an -abstract measurement of function's size. In no way, it represents a count -of assembly instructions and as such its exact meaning might change from one -release to an another. -.Ip "\fB\-fkeep-inline-functions\fR" 4 -.IX Item "-fkeep-inline-functions" -Even if all calls to a given function are integrated, and the function -is declared \f(CW\*(C`static\*(C'\fR, nevertheless output a separate run-time -callable version of the function. This switch does not affect -\&\f(CW\*(C`extern inline\*(C'\fR functions. -.Ip "\fB\-fkeep-static-consts\fR" 4 -.IX Item "-fkeep-static-consts" -Emit variables declared \f(CW\*(C`static const\*(C'\fR when optimization isn't turned -on, even if the variables aren't referenced. -.Sp -\&\s-1GCC\s0 enables this option by default. If you want to force the compiler to -check if the variable was referenced, regardless of whether or not -optimization is turned on, use the \fB\-fno-keep-static-consts\fR option. -.Ip "\fB\-fmerge-constants\fR" 4 -.IX Item "-fmerge-constants" -Attempt to merge identical constants (string constants and floating point -constants) accross compilation units. -.Sp -This option is default for optimized compilation if assembler and linker -support it. Use \fB\-fno-merge-constants\fR to inhibit this behavior. -.Ip "\fB\-fmerge-all-constants\fR" 4 -.IX Item "-fmerge-all-constants" -Attempt to merge identical constants and identical variables. -.Sp -This option implies \fB\-fmerge-constants\fR. In addition to -\&\fB\-fmerge-constants\fR this considers e.g. even constant initialized -arrays or initialized constant variables with integral or floating point -types. Languages like C or \*(C+ require each non-automatic variable to -have distinct location, so using this option will result in non-conforming -behavior. -.Ip "\fB\-fno-branch-count-reg\fR" 4 -.IX Item "-fno-branch-count-reg" -Do not use ``decrement and branch'' instructions on a count register, -but instead generate a sequence of instructions that decrement a -register, compare it against zero, then branch based upon the result. -This option is only meaningful on architectures that support such -instructions, which include x86, PowerPC, \s-1IA-64\s0 and S/390. -.Ip "\fB\-fno-function-cse\fR" 4 -.IX Item "-fno-function-cse" -Do not put function addresses in registers; make each instruction that -calls a constant function contain the function's address explicitly. -.Sp -This option results in less efficient code, but some strange hacks -that alter the assembler output may be confused by the optimizations -performed when this option is not used. -.Ip "\fB\-ffast-math\fR" 4 -.IX Item "-ffast-math" -Sets \fB\-fno-math-errno\fR, \fB\-funsafe-math-optimizations\fR, and \fB\-fno-trapping-math\fR. -.Sp -This option causes the preprocessor macro \f(CW\*(C`_\|_FAST_MATH_\|_\*(C'\fR to be defined. -.Sp -This option should never be turned on by any \fB\-O\fR option since -it can result in incorrect output for programs which depend on -an exact implementation of \s-1IEEE\s0 or \s-1ISO\s0 rules/specifications for -math functions. -.Ip "\fB\-fno-math-errno\fR" 4 -.IX Item "-fno-math-errno" -Do not set \s-1ERRNO\s0 after calling math functions that are executed -with a single instruction, e.g., sqrt. A program that relies on -\&\s-1IEEE\s0 exceptions for math error handling may want to use this flag -for speed while maintaining \s-1IEEE\s0 arithmetic compatibility. -.Sp -This option should never be turned on by any \fB\-O\fR option since -it can result in incorrect output for programs which depend on -an exact implementation of \s-1IEEE\s0 or \s-1ISO\s0 rules/specifications for -math functions. -.Sp -The default is \fB\-fmath-errno\fR. -.Ip "\fB\-funsafe-math-optimizations\fR" 4 -.IX Item "-funsafe-math-optimizations" -Allow optimizations for floating-point arithmetic that (a) assume -that arguments and results are valid and (b) may violate \s-1IEEE\s0 or -\&\s-1ANSI\s0 standards. When used at link-time, it may include libraries -or startup files that change the default \s-1FPU\s0 control word or other -similar optimizations. -.Sp -This option should never be turned on by any \fB\-O\fR option since -it can result in incorrect output for programs which depend on -an exact implementation of \s-1IEEE\s0 or \s-1ISO\s0 rules/specifications for -math functions. -.Sp -The default is \fB\-fno-unsafe-math-optimizations\fR. -.Ip "\fB\-fno-trapping-math\fR" 4 -.IX Item "-fno-trapping-math" -Compile code assuming that floating-point operations cannot generate -user-visible traps. Setting this option may allow faster code -if one relies on ``non-stop'' \s-1IEEE\s0 arithmetic, for example. -.Sp -This option should never be turned on by any \fB\-O\fR option since -it can result in incorrect output for programs which depend on -an exact implementation of \s-1IEEE\s0 or \s-1ISO\s0 rules/specifications for -math functions. -.Sp -The default is \fB\-ftrapping-math\fR. -.Ip "\fB\-fbounds-check\fR" 4 -.IX Item "-fbounds-check" -For front-ends that support it, generate additional code to check that -indices used to access arrays are within the declared range. This is -currenly only supported by the Java and Fortran 77 front-ends, where -this option defaults to true and false respectively. -.PP -The following options control specific optimizations. The \fB\-O2\fR -option turns on all of these optimizations except \fB\-funroll-loops\fR -and \fB\-funroll-all-loops\fR. On most machines, the \fB\-O\fR option -turns on the \fB\-fthread-jumps\fR and \fB\-fdelayed-branch\fR options, -but specific machines may handle it differently. -.PP -You can use the following flags in the rare cases when ``fine-tuning'' -of optimizations to be performed is desired. -.PP -Not all of the optimizations performed by \s-1GCC\s0 have \fB\-f\fR options -to control them. -.Ip "\fB\-fstrength-reduce\fR" 4 -.IX Item "-fstrength-reduce" -Perform the optimizations of loop strength reduction and -elimination of iteration variables. -.Ip "\fB\-fthread-jumps\fR" 4 -.IX Item "-fthread-jumps" -Perform optimizations where we check to see if a jump branches to a -location where another comparison subsumed by the first is found. If -so, the first branch is redirected to either the destination of the -second branch or a point immediately following it, depending on whether -the condition is known to be true or false. -.Ip "\fB\-fcse-follow-jumps\fR" 4 -.IX Item "-fcse-follow-jumps" -In common subexpression elimination, scan through jump instructions -when the target of the jump is not reached by any other path. For -example, when \s-1CSE\s0 encounters an \f(CW\*(C`if\*(C'\fR statement with an -\&\f(CW\*(C`else\*(C'\fR clause, \s-1CSE\s0 will follow the jump when the condition -tested is false. -.Ip "\fB\-fcse-skip-blocks\fR" 4 -.IX Item "-fcse-skip-blocks" -This is similar to \fB\-fcse-follow-jumps\fR, but causes \s-1CSE\s0 to -follow jumps which conditionally skip over blocks. When \s-1CSE\s0 -encounters a simple \f(CW\*(C`if\*(C'\fR statement with no else clause, -\&\fB\-fcse-skip-blocks\fR causes \s-1CSE\s0 to follow the jump around the -body of the \f(CW\*(C`if\*(C'\fR. -.Ip "\fB\-frerun-cse-after-loop\fR" 4 -.IX Item "-frerun-cse-after-loop" -Re-run common subexpression elimination after loop optimizations has been -performed. -.Ip "\fB\-frerun-loop-opt\fR" 4 -.IX Item "-frerun-loop-opt" -Run the loop optimizer twice. -.Ip "\fB\-fgcse\fR" 4 -.IX Item "-fgcse" -Perform a global common subexpression elimination pass. -This pass also performs global constant and copy propagation. -.Sp -\&\fINote:\fR When compiling a program using computed gotos, a \s-1GCC\s0 -extension, you may get better runtime performance if you disable -the global common subexpression elmination pass by adding -\&\fB\-fno-gcse\fR to the command line. -.Ip "\fB\-fgcse-lm\fR" 4 -.IX Item "-fgcse-lm" -When \fB\-fgcse-lm\fR is enabled, global common subexpression elimination will -attempt to move loads which are only killed by stores into themselves. This -allows a loop containing a load/store sequence to be changed to a load outside -the loop, and a copy/store within the loop. -.Ip "\fB\-fgcse-sm\fR" 4 -.IX Item "-fgcse-sm" -When \fB\-fgcse-sm\fR is enabled, A store motion pass is run after global common -subexpression elimination. This pass will attempt to move stores out of loops. -When used in conjunction with \fB\-fgcse-lm\fR, loops containing a load/store sequence -can be changed to a load before the loop and a store after the loop. -.Ip "\fB\-fdelete-null-pointer-checks\fR" 4 -.IX Item "-fdelete-null-pointer-checks" -Use global dataflow analysis to identify and eliminate useless checks -for null pointers. The compiler assumes that dereferencing a null -pointer would have halted the program. If a pointer is checked after -it has already been dereferenced, it cannot be null. -.Sp -In some environments, this assumption is not true, and programs can -safely dereference null pointers. Use -\&\fB\-fno-delete-null-pointer-checks\fR to disable this optimization -for programs which depend on that behavior. -.Ip "\fB\-fexpensive-optimizations\fR" 4 -.IX Item "-fexpensive-optimizations" -Perform a number of minor optimizations that are relatively expensive. -.Ip "\fB\-foptimize-register-move\fR" 4 -.IX Item "-foptimize-register-move" -.PD 0 -.Ip "\fB\-fregmove\fR" 4 -.IX Item "-fregmove" -.PD -Attempt to reassign register numbers in move instructions and as -operands of other simple instructions in order to maximize the amount of -register tying. This is especially helpful on machines with two-operand -instructions. \s-1GCC\s0 enables this optimization by default with \fB\-O2\fR -or higher. -.Sp -Note \fB\-fregmove\fR and \fB\-foptimize-register-move\fR are the same -optimization. -.Ip "\fB\-fdelayed-branch\fR" 4 -.IX Item "-fdelayed-branch" -If supported for the target machine, attempt to reorder instructions -to exploit instruction slots available after delayed branch -instructions. -.Ip "\fB\-fschedule-insns\fR" 4 -.IX Item "-fschedule-insns" -If supported for the target machine, attempt to reorder instructions to -eliminate execution stalls due to required data being unavailable. This -helps machines that have slow floating point or memory load instructions -by allowing other instructions to be issued until the result of the load -or floating point instruction is required. -.Ip "\fB\-fschedule-insns2\fR" 4 -.IX Item "-fschedule-insns2" -Similar to \fB\-fschedule-insns\fR, but requests an additional pass of -instruction scheduling after register allocation has been done. This is -especially useful on machines with a relatively small number of -registers and where memory load instructions take more than one cycle. -.Ip "\fB\-fno-sched-interblock\fR" 4 -.IX Item "-fno-sched-interblock" -Don't schedule instructions across basic blocks. This is normally -enabled by default when scheduling before register allocation, i.e. -with \fB\-fschedule-insns\fR or at \fB\-O2\fR or higher. -.Ip "\fB\-fno-sched-spec\fR" 4 -.IX Item "-fno-sched-spec" -Don't allow speculative motion of non-load instructions. This is normally -enabled by default when scheduling before register allocation, i.e. -with \fB\-fschedule-insns\fR or at \fB\-O2\fR or higher. -.Ip "\fB\-fsched-spec-load\fR" 4 -.IX Item "-fsched-spec-load" -Allow speculative motion of some load instructions. This only makes -sense when scheduling before register allocation, i.e. with -\&\fB\-fschedule-insns\fR or at \fB\-O2\fR or higher. -.Ip "\fB\-fsched-spec-load-dangerous\fR" 4 -.IX Item "-fsched-spec-load-dangerous" -Allow speculative motion of more load instructions. This only makes -sense when scheduling before register allocation, i.e. with -\&\fB\-fschedule-insns\fR or at \fB\-O2\fR or higher. -.Ip "\fB\-ffunction-sections\fR" 4 -.IX Item "-ffunction-sections" -.PD 0 -.Ip "\fB\-fdata-sections\fR" 4 -.IX Item "-fdata-sections" -.PD -Place each function or data item into its own section in the output -file if the target supports arbitrary sections. The name of the -function or the name of the data item determines the section's name -in the output file. -.Sp -Use these options on systems where the linker can perform optimizations -to improve locality of reference in the instruction space. \s-1HPPA\s0 -processors running \s-1HP-UX\s0 and Sparc processors running Solaris 2 have -linkers with such optimizations. Other systems using the \s-1ELF\s0 object format -as well as \s-1AIX\s0 may have these optimizations in the future. -.Sp -Only use these options when there are significant benefits from doing -so. When you specify these options, the assembler and linker will -create larger object and executable files and will also be slower. -You will not be able to use \f(CW\*(C`gprof\*(C'\fR on all systems if you -specify this option and you may have problems with debugging if -you specify both this option and \fB\-g\fR. -.Ip "\fB\-fcaller-saves\fR" 4 -.IX Item "-fcaller-saves" -Enable values to be allocated in registers that will be clobbered by -function calls, by emitting extra instructions to save and restore the -registers around such calls. Such allocation is done only when it -seems to result in better code than would otherwise be produced. -.Sp -This option is always enabled by default on certain machines, usually -those which have no call-preserved registers to use instead. -.Sp -For all machines, optimization level 2 and higher enables this flag by -default. -.Ip "\fB\-funroll-loops\fR" 4 -.IX Item "-funroll-loops" -Unroll loops whose number of iterations can be determined at compile -time or upon entry to the loop. \fB\-funroll-loops\fR implies both -\&\fB\-fstrength-reduce\fR and \fB\-frerun-cse-after-loop\fR. This -option makes code larger, and may or may not make it run faster. -.Ip "\fB\-funroll-all-loops\fR" 4 -.IX Item "-funroll-all-loops" -Unroll all loops, even if their number of iterations is uncertain when -the loop is entered. This usually makes programs run more slowly. -\&\fB\-funroll-all-loops\fR implies the same options as -\&\fB\-funroll-loops\fR, -.Ip "\fB\-fprefetch-loop-arrays\fR" 4 -.IX Item "-fprefetch-loop-arrays" -If supported by the target machine, generate instructions to prefetch -memory to improve the performance of loops that access large arrays. -.Ip "\fB\-fmove-all-movables\fR" 4 -.IX Item "-fmove-all-movables" -Forces all invariant computations in loops to be moved -outside the loop. -.Ip "\fB\-freduce-all-givs\fR" 4 -.IX Item "-freduce-all-givs" -Forces all general-induction variables in loops to be -strength-reduced. -.Sp -\&\fINote:\fR When compiling programs written in Fortran, -\&\fB\-fmove-all-movables\fR and \fB\-freduce-all-givs\fR are enabled -by default when you use the optimizer. -.Sp -These options may generate better or worse code; results are highly -dependent on the structure of loops within the source code. -.Sp -These two options are intended to be removed someday, once -they have helped determine the efficacy of various -approaches to improving loop optimizations. -.Sp -Please let us (<\fBgcc@gcc.gnu.org\fR> and <\fBfortran@gnu.org\fR>) -know how use of these options affects -the performance of your production code. -We're very interested in code that runs \fIslower\fR -when these options are \fIenabled\fR. -.Ip "\fB\-fno-peephole\fR" 4 -.IX Item "-fno-peephole" -.PD 0 -.Ip "\fB\-fno-peephole2\fR" 4 -.IX Item "-fno-peephole2" -.PD -Disable any machine-specific peephole optimizations. The difference -between \fB\-fno-peephole\fR and \fB\-fno-peephole2\fR is in how they -are implemented in the compiler; some targets use one, some use the -other, a few use both. -.Ip "\fB\-fbranch-probabilities\fR" 4 -.IX Item "-fbranch-probabilities" -After running a program compiled with \fB\-fprofile-arcs\fR, you can compile it a second time using -\&\fB\-fbranch-probabilities\fR, to improve optimizations based on -the number of times each branch was taken. When the program -compiled with \fB\-fprofile-arcs\fR exits it saves arc execution -counts to a file called \fI\fIsourcename\fI.da\fR for each source -file The information in this data file is very dependent on the -structure of the generated code, so you must use the same source code -and the same optimization options for both compilations. -.Sp -With \fB\-fbranch-probabilities\fR, \s-1GCC\s0 puts a \fB\s-1REG_EXEC_COUNT\s0\fR -note on the first instruction of each basic block, and a -\&\fB\s-1REG_BR_PROB\s0\fR note on each \fB\s-1JUMP_INSN\s0\fR and \fB\s-1CALL_INSN\s0\fR. -These can be used to improve optimization. Currently, they are only -used in one place: in \fIreorg.c\fR, instead of guessing which path a -branch is mostly to take, the \fB\s-1REG_BR_PROB\s0\fR values are used to -exactly determine which path is taken more often. -.Ip "\fB\-fno-guess-branch-probability\fR" 4 -.IX Item "-fno-guess-branch-probability" -Do not guess branch probabilities using a randomized model. -.Sp -Sometimes gcc will opt to use a randomized model to guess branch -probabilities, when none are available from either profiling feedback -(\fB\-fprofile-arcs\fR) or \fB_\|_builtin_expect\fR. This means that -different runs of the compiler on the same program may produce different -object code. -.Sp -In a hard real-time system, people don't want different runs of the -compiler to produce code that has different behavior; minimizing -non-determinism is of paramount import. This switch allows users to -reduce non-determinism, possibly at the expense of inferior -optimization. -.Ip "\fB\-fstrict-aliasing\fR" 4 -.IX Item "-fstrict-aliasing" -Allows the compiler to assume the strictest aliasing rules applicable to -the language being compiled. For C (and \*(C+), this activates -optimizations based on the type of expressions. In particular, an -object of one type is assumed never to reside at the same address as an -object of a different type, unless the types are almost the same. For -example, an \f(CW\*(C`unsigned int\*(C'\fR can alias an \f(CW\*(C`int\*(C'\fR, but not a -\&\f(CW\*(C`void*\*(C'\fR or a \f(CW\*(C`double\*(C'\fR. A character type may alias any other -type. -.Sp -Pay special attention to code like this: -.Sp -.Vb 4 -\& union a_union { -\& int i; -\& double d; -\& }; -.Ve -.Vb 5 -\& int f() { -\& a_union t; -\& t.d = 3.0; -\& return t.i; -\& } -.Ve -The practice of reading from a different union member than the one most -recently written to (called ``type-punning'') is common. Even with -\&\fB\-fstrict-aliasing\fR, type-punning is allowed, provided the memory -is accessed through the union type. So, the code above will work as -expected. However, this code might not: -.Sp -.Vb 7 -\& int f() { -\& a_union t; -\& int* ip; -\& t.d = 3.0; -\& ip = &t.i; -\& return *ip; -\& } -.Ve -Every language that wishes to perform language-specific alias analysis -should define a function that computes, given an \f(CW\*(C`tree\*(C'\fR -node, an alias set for the node. Nodes in different alias sets are not -allowed to alias. For an example, see the C front-end function -\&\f(CW\*(C`c_get_alias_set\*(C'\fR. -.Ip "\fB\-falign-functions\fR" 4 -.IX Item "-falign-functions" -.PD 0 -.Ip "\fB\-falign-functions=\fR\fIn\fR" 4 -.IX Item "-falign-functions=n" -.PD -Align the start of functions to the next power-of-two greater than -\&\fIn\fR, skipping up to \fIn\fR bytes. For instance, -\&\fB\-falign-functions=32\fR aligns functions to the next 32\-byte -boundary, but \fB\-falign-functions=24\fR would align to the next -32\-byte boundary only if this can be done by skipping 23 bytes or less. -.Sp -\&\fB\-fno-align-functions\fR and \fB\-falign-functions=1\fR are -equivalent and mean that functions will not be aligned. -.Sp -Some assemblers only support this flag when \fIn\fR is a power of two; -in that case, it is rounded up. -.Sp -If \fIn\fR is not specified, use a machine-dependent default. -.Ip "\fB\-falign-labels\fR" 4 -.IX Item "-falign-labels" -.PD 0 -.Ip "\fB\-falign-labels=\fR\fIn\fR" 4 -.IX Item "-falign-labels=n" -.PD -Align all branch targets to a power-of-two boundary, skipping up to -\&\fIn\fR bytes like \fB\-falign-functions\fR. This option can easily -make code slower, because it must insert dummy operations for when the -branch target is reached in the usual flow of the code. -.Sp -If \fB\-falign-loops\fR or \fB\-falign-jumps\fR are applicable and -are greater than this value, then their values are used instead. -.Sp -If \fIn\fR is not specified, use a machine-dependent default which is -very likely to be \fB1\fR, meaning no alignment. -.Ip "\fB\-falign-loops\fR" 4 -.IX Item "-falign-loops" -.PD 0 -.Ip "\fB\-falign-loops=\fR\fIn\fR" 4 -.IX Item "-falign-loops=n" -.PD -Align loops to a power-of-two boundary, skipping up to \fIn\fR bytes -like \fB\-falign-functions\fR. The hope is that the loop will be -executed many times, which will make up for any execution of the dummy -operations. -.Sp -If \fIn\fR is not specified, use a machine-dependent default. -.Ip "\fB\-falign-jumps\fR" 4 -.IX Item "-falign-jumps" -.PD 0 -.Ip "\fB\-falign-jumps=\fR\fIn\fR" 4 -.IX Item "-falign-jumps=n" -.PD -Align branch targets to a power-of-two boundary, for branch targets -where the targets can only be reached by jumping, skipping up to \fIn\fR -bytes like \fB\-falign-functions\fR. In this case, no dummy operations -need be executed. -.Sp -If \fIn\fR is not specified, use a machine-dependent default. -.Ip "\fB\-fssa\fR" 4 -.IX Item "-fssa" -Perform optimizations in static single assignment form. Each function's -flow graph is translated into \s-1SSA\s0 form, optimizations are performed, and -the flow graph is translated back from \s-1SSA\s0 form. Users should not -specify this option, since it is not yet ready for production use. -.Ip "\fB\-fssa-ccp\fR" 4 -.IX Item "-fssa-ccp" -Perform Sparse Conditional Constant Propagation in \s-1SSA\s0 form. Requires -\&\fB\-fssa\fR. Like \fB\-fssa\fR, this is an experimental feature. -.Ip "\fB\-fssa-dce\fR" 4 -.IX Item "-fssa-dce" -Perform aggressive dead-code elimination in \s-1SSA\s0 form. Requires \fB\-fssa\fR. -Like \fB\-fssa\fR, this is an experimental feature. -.Ip "\fB\-fsingle-precision-constant\fR" 4 -.IX Item "-fsingle-precision-constant" -Treat floating point constant as single precision constant instead of -implicitly converting it to double precision constant. -.Ip "\fB\-frename-registers\fR" 4 -.IX Item "-frename-registers" -Attempt to avoid false dependencies in scheduled code by making use -of registers left over after register allocation. This optimization -will most benefit processors with lots of registers. It can, however, -make debugging impossible, since variables will no longer stay in -a ``home register''. -.Ip "\fB\-fno-cprop-registers\fR" 4 -.IX Item "-fno-cprop-registers" -After register allocation and post-register allocation instruction splitting, -we perform a copy-propagation pass to try to reduce scheduling dependencies -and occasionally eliminate the copy. -.Ip "\fB\*(--param\fR \fIname\fR\fB=\fR\fIvalue\fR" 4 -.IX Item "param name=value" -In some places, \s-1GCC\s0 uses various constants to control the amount of -optimization that is done. For example, \s-1GCC\s0 will not inline functions -that contain more that a certain number of instructions. You can -control some of these constants on the command-line using the -\&\fB\*(--param\fR option. -.Sp -In each case, the \fIvalue\fR is an integer. The allowable choices for -\&\fIname\fR are given in the following table: -.RS 4 -.Ip "\fBmax-delay-slot-insn-search\fR" 4 -.IX Item "max-delay-slot-insn-search" -The maximum number of instructions to consider when looking for an -instruction to fill a delay slot. If more than this arbitrary number of -instructions is searched, the time savings from filling the delay slot -will be minimal so stop searching. Increasing values mean more -aggressive optimization, making the compile time increase with probably -small improvement in executable run time. -.Ip "\fBmax-delay-slot-live-search\fR" 4 -.IX Item "max-delay-slot-live-search" -When trying to fill delay slots, the maximum number of instructions to -consider when searching for a block with valid live register -information. Increasing this arbitrarily chosen value means more -aggressive optimization, increasing the compile time. This parameter -should be removed when the delay slot code is rewritten to maintain the -control-flow graph. -.Ip "\fBmax-gcse-memory\fR" 4 -.IX Item "max-gcse-memory" -The approximate maximum amount of memory that will be allocated in -order to perform the global common subexpression elimination -optimization. If more memory than specified is required, the -optimization will not be done. -.Ip "\fBmax-gcse-passes\fR" 4 -.IX Item "max-gcse-passes" -The maximum number of passes of \s-1GCSE\s0 to run. -.Ip "\fBmax-pending-list-length\fR" 4 -.IX Item "max-pending-list-length" -The maximum number of pending dependencies scheduling will allow -before flushing the current state and starting over. Large functions -with few branches or calls can create excessively large lists which -needlessly consume memory and resources. -.Ip "\fBmax-inline-insns\fR" 4 -.IX Item "max-inline-insns" -If an function contains more than this many instructions, it -will not be inlined. This option is precisely equivalent to -\&\fB\-finline-limit\fR. -.RE -.RS 4 -.RE -.Sh "Options Controlling the Preprocessor" -.IX Subsection "Options Controlling the Preprocessor" -These options control the C preprocessor, which is run on each C source -file before actual compilation. -.PP -If you use the \fB\-E\fR option, nothing is done except preprocessing. -Some of these options make sense only together with \fB\-E\fR because -they cause the preprocessor output to be unsuitable for actual -compilation. -.PP -You can use \fB\-Wp,\fR\fIoption\fR to bypass the compiler driver -and pass \fIoption\fR directly through to the preprocessor. If -\&\fIoption\fR contains commas, it is split into multiple options at the -commas. However, many options are modified, translated or interpreted -by the compiler driver before being passed to the preprocessor, and -\&\fB\-Wp\fR forcibly bypasses this phase. The preprocessor's direct -interface is undocumented and subject to change, so whenever possible -you should avoid using \fB\-Wp\fR and let the driver handle the -options instead. -.Ip "\fB\-D\fR \fIname\fR" 4 -.IX Item "-D name" -Predefine \fIname\fR as a macro, with definition \f(CW\*(C`1\*(C'\fR. -.Ip "\fB\-D\fR \fIname\fR\fB=\fR\fIdefinition\fR" 4 -.IX Item "-D name=definition" -Predefine \fIname\fR as a macro, with definition \fIdefinition\fR. -There are no restrictions on the contents of \fIdefinition\fR, but if -you are invoking the preprocessor from a shell or shell-like program you -may need to use the shell's quoting syntax to protect characters such as -spaces that have a meaning in the shell syntax. -.Sp -If you wish to define a function-like macro on the command line, write -its argument list with surrounding parentheses before the equals sign -(if any). Parentheses are meaningful to most shells, so you will need -to quote the option. With \fBsh\fR and \fBcsh\fR, -\&\fB\-D'\fR\fIname\fR\fB(\fR\fIargs...\fR\fB)=\fR\fIdefinition\fR\fB'\fR works. -.Sp -\&\fB\-D\fR and \fB\-U\fR options are processed in the order they -are given on the command line. All \fB\-imacros\fR \fIfile\fR and -\&\fB\-include\fR \fIfile\fR options are processed after all -\&\fB\-D\fR and \fB\-U\fR options. -.Ip "\fB\-U\fR \fIname\fR" 4 -.IX Item "-U name" -Cancel any previous definition of \fIname\fR, either built in or -provided with a \fB\-D\fR option. -.Ip "\fB\-undef\fR" 4 -.IX Item "-undef" -Do not predefine any system-specific macros. The common predefined -macros remain defined. -.Ip "\fB\-I\fR \fIdir\fR" 4 -.IX Item "-I dir" -Add the directory \fIdir\fR to the list of directories to be searched -for header files. -Directories named by \fB\-I\fR are searched before the standard -system include directories. -.Sp -It is dangerous to specify a standard system include directory in an -\&\fB\-I\fR option. This defeats the special treatment of system -headers -\&. It can also defeat the repairs to buggy system headers which \s-1GCC\s0 -makes when it is installed. -.Ip "\fB\-o\fR \fIfile\fR" 4 -.IX Item "-o file" -Write output to \fIfile\fR. This is the same as specifying \fIfile\fR -as the second non-option argument to \fBcpp\fR. \fBgcc\fR has a -different interpretation of a second non-option argument, so you must -use \fB\-o\fR to specify the output file. -.Ip "\fB\-Wall\fR" 4 -.IX Item "-Wall" -Turns on all optional warnings which are desirable for normal code. At -present this is \fB\-Wcomment\fR and \fB\-Wtrigraphs\fR. Note that -many of the preprocessor's warnings are on by default and have no -options to control them. -.Ip "\fB\-Wcomment\fR" 4 -.IX Item "-Wcomment" -.PD 0 -.Ip "\fB\-Wcomments\fR" 4 -.IX Item "-Wcomments" -.PD -Warn whenever a comment-start sequence \fB/*\fR appears in a \fB/*\fR -comment, or whenever a backslash-newline appears in a \fB//\fR comment. -(Both forms have the same effect.) -.Ip "\fB\-Wtrigraphs\fR" 4 -.IX Item "-Wtrigraphs" -Warn if any trigraphs are encountered. This option used to take effect -only if \fB\-trigraphs\fR was also specified, but now works -independently. Warnings are not given for trigraphs within comments, as -they do not affect the meaning of the program. -.Ip "\fB\-Wtraditional\fR" 4 -.IX Item "-Wtraditional" -Warn about certain constructs that behave differently in traditional and -\&\s-1ISO\s0 C. Also warn about \s-1ISO\s0 C constructs that have no traditional C -equivalent, and problematic constructs which should be avoided. -.Ip "\fB\-Wimport\fR" 4 -.IX Item "-Wimport" -Warn the first time \fB#import\fR is used. -.Ip "\fB\-Wundef\fR" 4 -.IX Item "-Wundef" -Warn whenever an identifier which is not a macro is encountered in an -\&\fB#if\fR directive, outside of \fBdefined\fR. Such identifiers are -replaced with zero. -.Ip "\fB\-Werror\fR" 4 -.IX Item "-Werror" -Make all warnings into hard errors. Source code which triggers warnings -will be rejected. -.Ip "\fB\-Wsystem-headers\fR" 4 -.IX Item "-Wsystem-headers" -Issue warnings for code in system headers. These are normally unhelpful -in finding bugs in your own code, therefore suppressed. If you are -responsible for the system library, you may want to see them. -.Ip "\fB\-w\fR" 4 -.IX Item "-w" -Suppress all warnings, including those which \s-1GNU\s0 \s-1CPP\s0 issues by default. -.Ip "\fB\-pedantic\fR" 4 -.IX Item "-pedantic" -Issue all the mandatory diagnostics listed in the C standard. Some of -them are left out by default, since they trigger frequently on harmless -code. -.Ip "\fB\-pedantic-errors\fR" 4 -.IX Item "-pedantic-errors" -Issue all the mandatory diagnostics, and make all mandatory diagnostics -into errors. This includes mandatory diagnostics that \s-1GCC\s0 issues -without \fB\-pedantic\fR but treats as warnings. -.Ip "\fB\-M\fR" 4 -.IX Item "-M" -Instead of outputting the result of preprocessing, output a rule -suitable for \fBmake\fR describing the dependencies of the main -source file. The preprocessor outputs one \fBmake\fR rule containing -the object file name for that source file, a colon, and the names of all -the included files, including those coming from \fB\-include\fR or -\&\fB\-imacros\fR command line options. -.Sp -Unless specified explicitly (with \fB\-MT\fR or \fB\-MQ\fR), the -object file name consists of the basename of the source file with any -suffix replaced with object file suffix. If there are many included -files then the rule is split into several lines using \fB\e\fR\-newline. -The rule has no commands. -.Sp -This option does not suppress the preprocessor's debug output, such as -\&\fB\-dM\fR. To avoid mixing such debug output with the dependency -rules you should explicitly specify the dependency output file with -\&\fB\-MF\fR, or use an environment variable like -\&\fB\s-1DEPENDENCIES_OUTPUT\s0\fR. Debug output -will still be sent to the regular output stream as normal. -.Sp -Passing \fB\-M\fR to the driver implies \fB\-E\fR. -.Ip "\fB\-MM\fR" 4 -.IX Item "-MM" -Like \fB\-M\fR but do not mention header files that are found in -system header directories, nor header files that are included, -directly or indirectly, from such a header. -.Sp -This implies that the choice of angle brackets or double quotes in an -\&\fB#include\fR directive does not in itself determine whether that -header will appear in \fB\-MM\fR dependency output. This is a -slight change in semantics from \s-1GCC\s0 versions 3.0 and earlier. -.Ip "\fB\-MF\fR \fIfile\fR" 4 -.IX Item "-MF file" -@anchor{\-MF} -When used with \fB\-M\fR or \fB\-MM\fR, specifies a -file to write the dependencies to. If no \fB\-MF\fR switch is given -the preprocessor sends the rules to the same place it would have sent -preprocessed output. -.Sp -When used with the driver options \fB\-MD\fR or \fB\-MMD\fR, -\&\fB\-MF\fR overrides the default dependency output file. -.Ip "\fB\-MG\fR" 4 -.IX Item "-MG" -When used with \fB\-M\fR or \fB\-MM\fR, \fB\-MG\fR says to treat missing -header files as generated files and assume they live in the same -directory as the source file. It suppresses preprocessed output, as a -missing header file is ordinarily an error. -.Sp -This feature is used in automatic updating of makefiles. -.Ip "\fB\-MP\fR" 4 -.IX Item "-MP" -This option instructs \s-1CPP\s0 to add a phony target for each dependency -other than the main file, causing each to depend on nothing. These -dummy rules work around errors \fBmake\fR gives if you remove header -files without updating the \fIMakefile\fR to match. -.Sp -This is typical output: -.Sp -.Vb 1 -\& test.o: test.c test.h -.Ve -.Vb 1 -\& test.h: -.Ve -.Ip "\fB\-MT\fR \fItarget\fR" 4 -.IX Item "-MT target" -Change the target of the rule emitted by dependency generation. By -default \s-1CPP\s0 takes the name of the main input file, including any path, -deletes any file suffix such as \fB.c\fR, and appends the platform's -usual object suffix. The result is the target. -.Sp -An \fB\-MT\fR option will set the target to be exactly the string you -specify. If you want multiple targets, you can specify them as a single -argument to \fB\-MT\fR, or use multiple \fB\-MT\fR options. -.Sp -For example, \fB\-MT\ '$(objpfx)foo.o'\fR might give -.Sp -.Vb 1 -\& $(objpfx)foo.o: foo.c -.Ve -.Ip "\fB\-MQ\fR \fItarget\fR" 4 -.IX Item "-MQ target" -Same as \fB\-MT\fR, but it quotes any characters which are special to -Make. \fB\-MQ\ '$(objpfx)foo.o'\fR gives -.Sp -.Vb 1 -\& $$(objpfx)foo.o: foo.c -.Ve -The default target is automatically quoted, as if it were given with -\&\fB\-MQ\fR. -.Ip "\fB\-MD\fR" 4 -.IX Item "-MD" -\&\fB\-MD\fR is equivalent to \fB\-M \-MF\fR \fIfile\fR, except that -\&\fB\-E\fR is not implied. The driver determines \fIfile\fR based on -whether an \fB\-o\fR option is given. If it is, the driver uses its -argument but with a suffix of \fI.d\fR, otherwise it take the -basename of the input file and applies a \fI.d\fR suffix. -.Sp -If \fB\-MD\fR is used in conjunction with \fB\-E\fR, any -\&\fB\-o\fR switch is understood to specify the dependency output file -(but \f(CW@pxref\fR{\-MF}), but if used without \fB\-E\fR, each \fB\-o\fR -is understood to specify a target object file. -.Sp -Since \fB\-E\fR is not implied, \fB\-MD\fR can be used to generate -a dependency output file as a side-effect of the compilation process. -.Ip "\fB\-MMD\fR" 4 -.IX Item "-MMD" -Like \fB\-MD\fR except mention only user header files, not system -\&\-header files. -.Ip "\fB\-x c\fR" 4 -.IX Item "-x c" -.PD 0 -.Ip "\fB\-x c++\fR" 4 -.IX Item "-x c++" -.Ip "\fB\-x objective-c\fR" 4 -.IX Item "-x objective-c" -.Ip "\fB\-x assembler-with-cpp\fR" 4 -.IX Item "-x assembler-with-cpp" -.PD -Specify the source language: C, \*(C+, Objective-C, or assembly. This has -nothing to do with standards conformance or extensions; it merely -selects which base syntax to expect. If you give none of these options, -cpp will deduce the language from the extension of the source file: -\&\fB.c\fR, \fB.cc\fR, \fB.m\fR, or \fB.S\fR. Some other common -extensions for \*(C+ and assembly are also recognized. If cpp does not -recognize the extension, it will treat the file as C; this is the most -generic mode. -.Sp -\&\fBNote:\fR Previous versions of cpp accepted a \fB\-lang\fR option -which selected both the language and the standards conformance level. -This option has been removed, because it conflicts with the \fB\-l\fR -option. -.Ip "\fB\-std=\fR\fIstandard\fR" 4 -.IX Item "-std=standard" -.PD 0 -.Ip "\fB\-ansi\fR" 4 -.IX Item "-ansi" -.PD -Specify the standard to which the code should conform. Currently cpp -only knows about the standards for C; other language standards will be -added in the future. -.Sp -\&\fIstandard\fR -may be one of: -.RS 4 -.if n .Ip "\f(CW""""iso9899:1990""""\fR" 4 -.el .Ip "\f(CWiso9899:1990\fR" 4 -.IX Item "iso9899:1990" -.PD 0 -.if n .Ip "\f(CW""""c89""""\fR" 4 -.el .Ip "\f(CWc89\fR" 4 -.IX Item "c89" -.PD -The \s-1ISO\s0 C standard from 1990. \fBc89\fR is the customary shorthand for -this version of the standard. -.Sp -The \fB\-ansi\fR option is equivalent to \fB\-std=c89\fR. -.if n .Ip "\f(CW""""iso9899:199409""""\fR" 4 -.el .Ip "\f(CWiso9899:199409\fR" 4 -.IX Item "iso9899:199409" -The 1990 C standard, as amended in 1994. -.if n .Ip "\f(CW""""iso9899:1999""""\fR" 4 -.el .Ip "\f(CWiso9899:1999\fR" 4 -.IX Item "iso9899:1999" -.PD 0 -.if n .Ip "\f(CW""""c99""""\fR" 4 -.el .Ip "\f(CWc99\fR" 4 -.IX Item "c99" -.if n .Ip "\f(CW""""iso9899:199x""""\fR" 4 -.el .Ip "\f(CWiso9899:199x\fR" 4 -.IX Item "iso9899:199x" -.if n .Ip "\f(CW""""c9x""""\fR" 4 -.el .Ip "\f(CWc9x\fR" 4 -.IX Item "c9x" -.PD -The revised \s-1ISO\s0 C standard, published in December 1999. Before -publication, this was known as C9X. -.if n .Ip "\f(CW""""gnu89""""\fR" 4 -.el .Ip "\f(CWgnu89\fR" 4 -.IX Item "gnu89" -The 1990 C standard plus \s-1GNU\s0 extensions. This is the default. -.if n .Ip "\f(CW""""gnu99""""\fR" 4 -.el .Ip "\f(CWgnu99\fR" 4 -.IX Item "gnu99" -.PD 0 -.if n .Ip "\f(CW""""gnu9x""""\fR" 4 -.el .Ip "\f(CWgnu9x\fR" 4 -.IX Item "gnu9x" -.PD -The 1999 C standard plus \s-1GNU\s0 extensions. -.RE -.RS 4 -.RE -.Ip "\fB\-I-\fR" 4 -.IX Item "-I-" -Split the include path. Any directories specified with \fB\-I\fR -options before \fB\-I-\fR are searched only for headers requested with -\&\f(CW\*(C`#include\ "\f(CIfile\f(CW"\*(C'\fR; they are not searched for -\&\f(CW\*(C`#include\ <\f(CIfile\f(CW>\*(C'\fR. If additional directories are -specified with \fB\-I\fR options after the \fB\-I-\fR, those -directories are searched for all \fB#include\fR directives. -.Sp -In addition, \fB\-I-\fR inhibits the use of the directory of the current -file directory as the first search directory for \f(CW\*(C`#include\ "\f(CIfile\f(CW"\*(C'\fR. -.Ip "\fB\-nostdinc\fR" 4 -.IX Item "-nostdinc" -Do not search the standard system directories for header files. -Only the directories you have specified with \fB\-I\fR options -(and the directory of the current file, if appropriate) are searched. -.Ip "\fB\-nostdinc++\fR" 4 -.IX Item "-nostdinc++" -Do not search for header files in the \*(C+\-specific standard directories, -but do still search the other standard directories. (This option is -used when building the \*(C+ library.) -.Ip "\fB\-include\fR \fIfile\fR" 4 -.IX Item "-include file" -Process \fIfile\fR as if \f(CW\*(C`#include "file"\*(C'\fR appeared as the first -line of the primary source file. However, the first directory searched -for \fIfile\fR is the preprocessor's working directory \fIinstead of\fR -the directory containing the main source file. If not found there, it -is searched for in the remainder of the \f(CW\*(C`#include "..."\*(C'\fR search -chain as normal. -.Sp -If multiple \fB\-include\fR options are given, the files are included -in the order they appear on the command line. -.Ip "\fB\-imacros\fR \fIfile\fR" 4 -.IX Item "-imacros file" -Exactly like \fB\-include\fR, except that any output produced by -scanning \fIfile\fR is thrown away. Macros it defines remain defined. -This allows you to acquire all the macros from a header without also -processing its declarations. -.Sp -All files specified by \fB\-imacros\fR are processed before all files -specified by \fB\-include\fR. -.Ip "\fB\-idirafter\fR \fIdir\fR" 4 -.IX Item "-idirafter dir" -Search \fIdir\fR for header files, but do it \fIafter\fR all -directories specified with \fB\-I\fR and the standard system directories -have been exhausted. \fIdir\fR is treated as a system include directory. -.Ip "\fB\-iprefix\fR \fIprefix\fR" 4 -.IX Item "-iprefix prefix" -Specify \fIprefix\fR as the prefix for subsequent \fB\-iwithprefix\fR -options. If the prefix represents a directory, you should include the -final \fB/\fR. -.Ip "\fB\-iwithprefix\fR \fIdir\fR" 4 -.IX Item "-iwithprefix dir" -.PD 0 -.Ip "\fB\-iwithprefixbefore\fR \fIdir\fR" 4 -.IX Item "-iwithprefixbefore dir" -.PD -Append \fIdir\fR to the prefix specified previously with -\&\fB\-iprefix\fR, and add the resulting directory to the include search -path. \fB\-iwithprefixbefore\fR puts it in the same place \fB\-I\fR -would; \fB\-iwithprefix\fR puts it where \fB\-idirafter\fR would. -.Sp -Use of these options is discouraged. -.Ip "\fB\-isystem\fR \fIdir\fR" 4 -.IX Item "-isystem dir" -Search \fIdir\fR for header files, after all directories specified by -\&\fB\-I\fR but before the standard system directories. Mark it -as a system directory, so that it gets the same special treatment as -is applied to the standard system directories. -.Ip "\fB\-fpreprocessed\fR" 4 -.IX Item "-fpreprocessed" -Indicate to the preprocessor that the input file has already been -preprocessed. This suppresses things like macro expansion, trigraph -conversion, escaped newline splicing, and processing of most directives. -The preprocessor still recognizes and removes comments, so that you can -pass a file preprocessed with \fB\-C\fR to the compiler without -problems. In this mode the integrated preprocessor is little more than -a tokenizer for the front ends. -.Sp -\&\fB\-fpreprocessed\fR is implicit if the input file has one of the -extensions \fB.i\fR, \fB.ii\fR or \fB.mi\fR. These are the -extensions that \s-1GCC\s0 uses for preprocessed files created by -\&\fB\-save-temps\fR. -.Ip "\fB\-ftabstop=\fR\fIwidth\fR" 4 -.IX Item "-ftabstop=width" -Set the distance between tab stops. This helps the preprocessor report -correct column numbers in warnings or errors, even if tabs appear on the -line. If the value is less than 1 or greater than 100, the option is -ignored. The default is 8. -.Ip "\fB\-fno-show-column\fR" 4 -.IX Item "-fno-show-column" -Do not print column numbers in diagnostics. This may be necessary if -diagnostics are being scanned by a program that does not understand the -column numbers, such as \fBdejagnu\fR. -.Ip "\fB\-A\fR \fIpredicate\fR\fB=\fR\fIanswer\fR" 4 -.IX Item "-A predicate=answer" -Make an assertion with the predicate \fIpredicate\fR and answer -\&\fIanswer\fR. This form is preferred to the older form \fB\-A\fR -\&\fIpredicate\fR\fB(\fR\fIanswer\fR\fB)\fR, which is still supported, because -it does not use shell special characters. -.Ip "\fB\-A -\fR\fIpredicate\fR\fB=\fR\fIanswer\fR" 4 -.IX Item "-A -predicate=answer" -Cancel an assertion with the predicate \fIpredicate\fR and answer -\&\fIanswer\fR. -.Ip "\fB\-A-\fR" 4 -.IX Item "-A-" -Cancel all predefined assertions and all assertions preceding it on -the command line. Also, undefine all predefined macros and all -macros preceding it on the command line. (This is a historical wart and -may change in the future.) -.Ip "\fB\-dCHARS\fR" 4 -.IX Item "-dCHARS" -\&\fI\s-1CHARS\s0\fR is a sequence of one or more of the following characters, -and must not be preceded by a space. Other characters are interpreted -by the compiler proper, or reserved for future versions of \s-1GCC\s0, and so -are silently ignored. If you specify characters whose behavior -conflicts, the result is undefined. -.RS 4 -.Ip "\fBM\fR" 4 -.IX Item "M" -Instead of the normal output, generate a list of \fB#define\fR -directives for all the macros defined during the execution of the -preprocessor, including predefined macros. This gives you a way of -finding out what is predefined in your version of the preprocessor. -Assuming you have no file \fIfoo.h\fR, the command -.Sp -.Vb 1 -\& touch foo.h; cpp -dM foo.h -.Ve -will show all the predefined macros. -.Ip "\fBD\fR" 4 -.IX Item "D" -Like \fBM\fR except in two respects: it does \fInot\fR include the -predefined macros, and it outputs \fIboth\fR the \fB#define\fR -directives and the result of preprocessing. Both kinds of output go to -the standard output file. -.Ip "\fBN\fR" 4 -.IX Item "N" -Like \fBD\fR, but emit only the macro names, not their expansions. -.Ip "\fBI\fR" 4 -.IX Item "I" -Output \fB#include\fR directives in addition to the result of -preprocessing. -.RE -.RS 4 -.RE -.Ip "\fB\-P\fR" 4 -.IX Item "-P" -Inhibit generation of linemarkers in the output from the preprocessor. -This might be useful when running the preprocessor on something that is -not C code, and will be sent to a program which might be confused by the -linemarkers. -.Ip "\fB\-C\fR" 4 -.IX Item "-C" -Do not discard comments. All comments are passed through to the output -file, except for comments in processed directives, which are deleted -along with the directive. -.Sp -You should be prepared for side effects when using \fB\-C\fR; it -causes the preprocessor to treat comments as tokens in their own right. -For example, comments appearing at the start of what would be a -directive line have the effect of turning that line into an ordinary -source line, since the first token on the line is no longer a \fB#\fR. -.Ip "\fB\-gcc\fR" 4 -.IX Item "-gcc" -Define the macros _\|_GNUC_\|_, _\|_GNUC_MINOR_\|_ and -_\|_GNUC_PATCHLEVEL_\|_. These are defined automatically when you use -\&\fBgcc \-E\fR; you can turn them off in that case with -\&\fB\-no-gcc\fR. -.Ip "\fB\-traditional\fR" 4 -.IX Item "-traditional" -Try to imitate the behavior of old-fashioned C, as opposed to \s-1ISO\s0 -C. -.Ip "\fB\-trigraphs\fR" 4 -.IX Item "-trigraphs" -Process trigraph sequences. -These are three-character sequences, all starting with \fB??\fR, that -are defined by \s-1ISO\s0 C to stand for single characters. For example, -\&\fB??/\fR stands for \fB\e\fR, so \fB'??/n'\fR is a character -constant for a newline. By default, \s-1GCC\s0 ignores trigraphs, but in -standard-conforming modes it converts them. See the \fB\-std\fR and -\&\fB\-ansi\fR options. -.Sp -The nine trigraphs and their replacements are -.Sp -.Vb 2 -\& Trigraph: ??( ??) ??< ??> ??= ??/ ??' ??! ??- -\& Replacement: [ ] { } # \e ^ | ~ -.Ve -.Ip "\fB\-remap\fR" 4 -.IX Item "-remap" -Enable special code to work around file systems which only permit very -short file names, such as \s-1MS-DOS\s0. -.Ip "\fB\-$\fR" 4 -.IX Item "-$" -Forbid the use of \fB$\fR in identifiers. The C standard allows -implementations to define extra characters that can appear in -identifiers. By default \s-1GNU\s0 \s-1CPP\s0 permits \fB$\fR, a common extension. -.Ip "\fB\-h\fR" 4 -.IX Item "-h" -.PD 0 -.Ip "\fB\*(--help\fR" 4 -.IX Item "help" -.Ip "\fB\*(--target-help\fR" 4 -.IX Item "target-help" -.PD -Print text describing all the command line options instead of -preprocessing anything. -.Ip "\fB\-v\fR" 4 -.IX Item "-v" -Verbose mode. Print out \s-1GNU\s0 \s-1CPP\s0's version number at the beginning of -execution, and report the final form of the include path. -.Ip "\fB\-H\fR" 4 -.IX Item "-H" -Print the name of each header file used, in addition to other normal -activities. Each name is indented to show how deep in the -\&\fB#include\fR stack it is. -.Ip "\fB\-version\fR" 4 -.IX Item "-version" -.PD 0 -.Ip "\fB\*(--version\fR" 4 -.IX Item "version" -.PD -Print out \s-1GNU\s0 \s-1CPP\s0's version number. With one dash, proceed to -preprocess as normal. With two dashes, exit immediately. -.Sh "Passing Options to the Assembler" -.IX Subsection "Passing Options to the Assembler" -You can pass options to the assembler. -.Ip "\fB\-Wa,\fR\fIoption\fR" 4 -.IX Item "-Wa,option" -Pass \fIoption\fR as an option to the assembler. If \fIoption\fR -contains commas, it is split into multiple options at the commas. -.Sh "Options for Linking" -.IX Subsection "Options for Linking" -These options come into play when the compiler links object files into -an executable output file. They are meaningless if the compiler is -not doing a link step. -.Ip "\fIobject-file-name\fR" 4 -.IX Item "object-file-name" -A file name that does not end in a special recognized suffix is -considered to name an object file or library. (Object files are -distinguished from libraries by the linker according to the file -contents.) If linking is done, these object files are used as input -to the linker. -.Ip "\fB\-c\fR" 4 -.IX Item "-c" -.PD 0 -.Ip "\fB\-S\fR" 4 -.IX Item "-S" -.Ip "\fB\-E\fR" 4 -.IX Item "-E" -.PD -If any of these options is used, then the linker is not run, and -object file names should not be used as arguments. -.Ip "\fB\-l\fR\fIlibrary\fR" 4 -.IX Item "-llibrary" -.PD 0 -.Ip "\fB\-l\fR \fIlibrary\fR" 4 -.IX Item "-l library" -.PD -Search the library named \fIlibrary\fR when linking. (The second -alternative with the library as a separate argument is only for -\&\s-1POSIX\s0 compliance and is not recommended.) -.Sp -It makes a difference where in the command you write this option; the -linker searches and processes libraries and object files in the order they -are specified. Thus, \fBfoo.o \-lz bar.o\fR searches library \fBz\fR -after file \fIfoo.o\fR but before \fIbar.o\fR. If \fIbar.o\fR refers -to functions in \fBz\fR, those functions may not be loaded. -.Sp -The linker searches a standard list of directories for the library, -which is actually a file named \fIlib\fIlibrary\fI.a\fR. The linker -then uses this file as if it had been specified precisely by name. -.Sp -The directories searched include several standard system directories -plus any that you specify with \fB\-L\fR. -.Sp -Normally the files found this way are library files\-\-\-archive files -whose members are object files. The linker handles an archive file by -scanning through it for members which define symbols that have so far -been referenced but not defined. But if the file that is found is an -ordinary object file, it is linked in the usual fashion. The only -difference between using an \fB\-l\fR option and specifying a file name -is that \fB\-l\fR surrounds \fIlibrary\fR with \fBlib\fR and \fB.a\fR -and searches several directories. -.Ip "\fB\-lobjc\fR" 4 -.IX Item "-lobjc" -You need this special case of the \fB\-l\fR option in order to -link an Objective-C program. -.Ip "\fB\-nostartfiles\fR" 4 -.IX Item "-nostartfiles" -Do not use the standard system startup files when linking. -The standard system libraries are used normally, unless \fB\-nostdlib\fR -or \fB\-nodefaultlibs\fR is used. -.Ip "\fB\-nodefaultlibs\fR" 4 -.IX Item "-nodefaultlibs" -Do not use the standard system libraries when linking. -Only the libraries you specify will be passed to the linker. -The standard startup files are used normally, unless \fB\-nostartfiles\fR -is used. The compiler may generate calls to memcmp, memset, and memcpy -for System V (and \s-1ISO\s0 C) environments or to bcopy and bzero for -\&\s-1BSD\s0 environments. These entries are usually resolved by entries in -libc. These entry points should be supplied through some other -mechanism when this option is specified. -.Ip "\fB\-nostdlib\fR" 4 -.IX Item "-nostdlib" -Do not use the standard system startup files or libraries when linking. -No startup files and only the libraries you specify will be passed to -the linker. The compiler may generate calls to memcmp, memset, and memcpy -for System V (and \s-1ISO\s0 C) environments or to bcopy and bzero for -\&\s-1BSD\s0 environments. These entries are usually resolved by entries in -libc. These entry points should be supplied through some other -mechanism when this option is specified. -.Sp -One of the standard libraries bypassed by \fB\-nostdlib\fR and -\&\fB\-nodefaultlibs\fR is \fIlibgcc.a\fR, a library of internal subroutines -that \s-1GCC\s0 uses to overcome shortcomings of particular machines, or special -needs for some languages. -.Sp -In most cases, you need \fIlibgcc.a\fR even when you want to avoid -other standard libraries. In other words, when you specify \fB\-nostdlib\fR -or \fB\-nodefaultlibs\fR you should usually specify \fB\-lgcc\fR as well. -This ensures that you have no unresolved references to internal \s-1GCC\s0 -library subroutines. (For example, \fB_\|_main\fR, used to ensure \*(C+ -constructors will be called.) -.Ip "\fB\-s\fR" 4 -.IX Item "-s" -Remove all symbol table and relocation information from the executable. -.Ip "\fB\-static\fR" 4 -.IX Item "-static" -On systems that support dynamic linking, this prevents linking with the shared -libraries. On other systems, this option has no effect. -.Ip "\fB\-shared\fR" 4 -.IX Item "-shared" -Produce a shared object which can then be linked with other objects to -form an executable. Not all systems support this option. For predictable -results, you must also specify the same set of options that were used to -generate code (\fB\-fpic\fR, \fB\-fPIC\fR, or model suboptions) -when you specify this option.[1] -.Ip "\fB\-shared-libgcc\fR" 4 -.IX Item "-shared-libgcc" -.PD 0 -.Ip "\fB\-static-libgcc\fR" 4 -.IX Item "-static-libgcc" -.PD -On systems that provide \fIlibgcc\fR as a shared library, these options -force the use of either the shared or static version respectively. -If no shared version of \fIlibgcc\fR was built when the compiler was -configured, these options have no effect. -.Sp -There are several situations in which an application should use the -shared \fIlibgcc\fR instead of the static version. The most common -of these is when the application wishes to throw and catch exceptions -across different shared libraries. In that case, each of the libraries -as well as the application itself should use the shared \fIlibgcc\fR. -.Sp -Therefore, the G++ and \s-1GCJ\s0 drivers automatically add -\&\fB\-shared-libgcc\fR whenever you build a shared library or a main -executable, because \*(C+ and Java programs typically use exceptions, so -this is the right thing to do. -.Sp -If, instead, you use the \s-1GCC\s0 driver to create shared libraries, you may -find that they will not always be linked with the shared \fIlibgcc\fR. -If \s-1GCC\s0 finds, at its configuration time, that you have a \s-1GNU\s0 linker that -does not support option \fB\*(--eh-frame-hdr\fR, it will link the shared -version of \fIlibgcc\fR into shared libraries by default. Otherwise, -it will take advantage of the linker and optimize away the linking with -the shared version of \fIlibgcc\fR, linking with the static version of -libgcc by default. This allows exceptions to propagate through such -shared libraries, without incurring relocation costs at library load -time. -.Sp -However, if a library or main executable is supposed to throw or catch -exceptions, you must link it using the G++ or \s-1GCJ\s0 driver, as appropriate -for the languages used in the program, or using the option -\&\fB\-shared-libgcc\fR, such that it is linked with the shared -\&\fIlibgcc\fR. -.Ip "\fB\-symbolic\fR" 4 -.IX Item "-symbolic" -Bind references to global symbols when building a shared object. Warn -about any unresolved references (unless overridden by the link editor -option \fB\-Xlinker \-z \-Xlinker defs\fR). Only a few systems support -this option. -.Ip "\fB\-Xlinker\fR \fIoption\fR" 4 -.IX Item "-Xlinker option" -Pass \fIoption\fR as an option to the linker. You can use this to -supply system-specific linker options which \s-1GCC\s0 does not know how to -recognize. -.Sp -If you want to pass an option that takes an argument, you must use -\&\fB\-Xlinker\fR twice, once for the option and once for the argument. -For example, to pass \fB\-assert definitions\fR, you must write -\&\fB\-Xlinker \-assert \-Xlinker definitions\fR. It does not work to write -\&\fB\-Xlinker \*(L"\-assert definitions\*(R"\fR, because this passes the entire -string as a single argument, which is not what the linker expects. -.Ip "\fB\-Wl,\fR\fIoption\fR" 4 -.IX Item "-Wl,option" -Pass \fIoption\fR as an option to the linker. If \fIoption\fR contains -commas, it is split into multiple options at the commas. -.Ip "\fB\-u\fR \fIsymbol\fR" 4 -.IX Item "-u symbol" -Pretend the symbol \fIsymbol\fR is undefined, to force linking of -library modules to define it. You can use \fB\-u\fR multiple times with -different symbols to force loading of additional library modules. -.Sh "Options for Directory Search" -.IX Subsection "Options for Directory Search" -These options specify directories to search for header files, for -libraries and for parts of the compiler: -.Ip "\fB\-I\fR\fIdir\fR" 4 -.IX Item "-Idir" -Add the directory \fIdir\fR to the head of the list of directories to be -searched for header files. This can be used to override a system header -file, substituting your own version, since these directories are -searched before the system header file directories. However, you should -not use this option to add directories that contain vendor-supplied -system header files (use \fB\-isystem\fR for that). If you use more than -one \fB\-I\fR option, the directories are scanned in left-to-right -order; the standard system directories come after. -.Sp -If a standard system include directory, or a directory specified with -\&\fB\-isystem\fR, is also specified with \fB\-I\fR, the \fB\-I\fR -option will be ignored. The directory will still be searched but as a -system directory at its normal position in the system include chain. -This is to ensure that \s-1GCC\s0's procedure to fix buggy system headers and -the ordering for the include_next directive are not inadvertantly changed. -If you really need to change the search order for system directories, -use the \fB\-nostdinc\fR and/or \fB\-isystem\fR options. -.Ip "\fB\-I-\fR" 4 -.IX Item "-I-" -Any directories you specify with \fB\-I\fR options before the \fB\-I-\fR -option are searched only for the case of \fB#include "\fR\fIfile\fR\fB"\fR; -they are not searched for \fB#include <\fR\fIfile\fR\fB>\fR. -.Sp -If additional directories are specified with \fB\-I\fR options after -the \fB\-I-\fR, these directories are searched for all \fB#include\fR -directives. (Ordinarily \fIall\fR \fB\-I\fR directories are used -this way.) -.Sp -In addition, the \fB\-I-\fR option inhibits the use of the current -directory (where the current input file came from) as the first search -directory for \fB#include "\fR\fIfile\fR\fB"\fR. There is no way to -override this effect of \fB\-I-\fR. With \fB\-I.\fR you can specify -searching the directory which was current when the compiler was -invoked. That is not exactly the same as what the preprocessor does -by default, but it is often satisfactory. -.Sp -\&\fB\-I-\fR does not inhibit the use of the standard system directories -for header files. Thus, \fB\-I-\fR and \fB\-nostdinc\fR are -independent. -.Ip "\fB\-L\fR\fIdir\fR" 4 -.IX Item "-Ldir" -Add directory \fIdir\fR to the list of directories to be searched -for \fB\-l\fR. -.Ip "\fB\-B\fR\fIprefix\fR" 4 -.IX Item "-Bprefix" -This option specifies where to find the executables, libraries, -include files, and data files of the compiler itself. -.Sp -The compiler driver program runs one or more of the subprograms -\&\fIcpp\fR, \fIcc1\fR, \fIas\fR and \fIld\fR. It tries -\&\fIprefix\fR as a prefix for each program it tries to run, both with and -without \fImachine\fR\fB/\fR\fIversion\fR\fB/\fR. -.Sp -For each subprogram to be run, the compiler driver first tries the -\&\fB\-B\fR prefix, if any. If that name is not found, or if \fB\-B\fR -was not specified, the driver tries two standard prefixes, which are -\&\fI/usr/lib/gcc/\fR and \fI/usr/local/lib/gcc-lib/\fR. If neither of -those results in a file name that is found, the unmodified program -name is searched for using the directories specified in your -\&\fB\s-1PATH\s0\fR environment variable. -.Sp -The compiler will check to see if the path provided by the \fB\-B\fR -refers to a directory, and if necessary it will add a directory -separator character at the end of the path. -.Sp -\&\fB\-B\fR prefixes that effectively specify directory names also apply -to libraries in the linker, because the compiler translates these -options into \fB\-L\fR options for the linker. They also apply to -includes files in the preprocessor, because the compiler translates these -options into \fB\-isystem\fR options for the preprocessor. In this case, -the compiler appends \fBinclude\fR to the prefix. -.Sp -The run-time support file \fIlibgcc.a\fR can also be searched for using -the \fB\-B\fR prefix, if needed. If it is not found there, the two -standard prefixes above are tried, and that is all. The file is left -out of the link if it is not found by those means. -.Sp -Another way to specify a prefix much like the \fB\-B\fR prefix is to use -the environment variable \fB\s-1GCC_EXEC_PREFIX\s0\fR. -.Sp -As a special kludge, if the path provided by \fB\-B\fR is -\&\fI[dir/]stage\fIN\fI/\fR, where \fIN\fR is a number in the range 0 to -9, then it will be replaced by \fI[dir/]include\fR. This is to help -with boot-strapping the compiler. -.Ip "\fB\-specs=\fR\fIfile\fR" 4 -.IX Item "-specs=file" -Process \fIfile\fR after the compiler reads in the standard \fIspecs\fR -file, in order to override the defaults that the \fIgcc\fR driver -program uses when determining what switches to pass to \fIcc1\fR, -\&\fIcc1plus\fR, \fIas\fR, \fIld\fR, etc. More than one -\&\fB\-specs=\fR\fIfile\fR can be specified on the command line, and they -are processed in order, from left to right. -.Sh "Specifying Target Machine and Compiler Version" -.IX Subsection "Specifying Target Machine and Compiler Version" -By default, \s-1GCC\s0 compiles code for the same type of machine that you -are using. However, it can also be installed as a cross-compiler, to -compile for some other type of machine. In fact, several different -configurations of \s-1GCC\s0, for different target machines, can be -installed side by side. Then you specify which one to use with the -\&\fB\-b\fR option. -.PP -In addition, older and newer versions of \s-1GCC\s0 can be installed side -by side. One of them (probably the newest) will be the default, but -you may sometimes wish to use another. -.Ip "\fB\-b\fR \fImachine\fR" 4 -.IX Item "-b machine" -The argument \fImachine\fR specifies the target machine for compilation. -This is useful when you have installed \s-1GCC\s0 as a cross-compiler. -.Sp -The value to use for \fImachine\fR is the same as was specified as the -machine type when configuring \s-1GCC\s0 as a cross-compiler. For -example, if a cross-compiler was configured with \fBconfigure -i386v\fR, meaning to compile for an 80386 running System V, then you -would specify \fB\-b i386v\fR to run that cross compiler. -.Sp -When you do not specify \fB\-b\fR, it normally means to compile for -the same type of machine that you are using. -.Ip "\fB\-V\fR \fIversion\fR" 4 -.IX Item "-V version" -The argument \fIversion\fR specifies which version of \s-1GCC\s0 to run. -This is useful when multiple versions are installed. For example, -\&\fIversion\fR might be \fB2.0\fR, meaning to run \s-1GCC\s0 version 2.0. -.Sp -The default version, when you do not specify \fB\-V\fR, is the last -version of \s-1GCC\s0 that you installed. -.PP -The \fB\-b\fR and \fB\-V\fR options actually work by controlling part of -the file name used for the executable files and libraries used for -compilation. A given version of \s-1GCC\s0, for a given target machine, is -normally kept in the directory \fI/usr/local/lib/gcc-lib/\fImachine\fI/\fIversion\fI\fR. -.PP -Thus, sites can customize the effect of \fB\-b\fR or \fB\-V\fR either by -changing the names of these directories or adding alternate names (or -symbolic links). If in directory \fI/usr/local/lib/gcc-lib/\fR the -file \fI80386\fR is a link to the file \fIi386v\fR, then \fB\-b -80386\fR becomes an alias for \fB\-b i386v\fR. -.PP -In one respect, the \fB\-b\fR or \fB\-V\fR do not completely change -to a different compiler: the top-level driver program \fBgcc\fR -that you originally invoked continues to run and invoke the other -executables (preprocessor, compiler per se, assembler and linker) -that do the real work. However, since no real work is done in the -driver program, it usually does not matter that the driver program -in use is not the one for the specified target. It is common for the -interface to the other executables to change incompatibly between -compiler versions, so unless the version specified is very close to that -of the driver (for example, \fB\-V 3.0\fR with a driver program from \s-1GCC\s0 -version 3.0.1), use of \fB\-V\fR may not work; for example, using -\&\fB\-V 2.95.2\fR will not work with a driver program from \s-1GCC\s0 3.0. -.PP -The only way that the driver program depends on the target machine is -in the parsing and handling of special machine-specific options. -However, this is controlled by a file which is found, along with the -other executables, in the directory for the specified version and -target machine. As a result, a single installed driver program adapts -to any specified target machine, and sufficiently similar compiler -versions. -.PP -The driver program executable does control one significant thing, -however: the default version and target machine. Therefore, you can -install different instances of the driver program, compiled for -different targets or versions, under different names. -.PP -For example, if the driver for version 2.0 is installed as \fBogcc\fR -and that for version 2.1 is installed as \fBgcc\fR, then the command -\&\fBgcc\fR will use version 2.1 by default, while \fBogcc\fR will use -2.0 by default. However, you can choose either version with either -command with the \fB\-V\fR option. -.Sh "Hardware Models and Configurations" -.IX Subsection "Hardware Models and Configurations" -Earlier we discussed the standard option \fB\-b\fR which chooses among -different installed compilers for completely different target -machines, such as \s-1VAX\s0 vs. 68000 vs. 80386. -.PP -In addition, each of these target machine types can have its own -special options, starting with \fB\-m\fR, to choose among various -hardware models or configurations\-\-\-for example, 68010 vs 68020, -floating coprocessor or none. A single installed version of the -compiler can compile for any model or configuration, according to the -options specified. -.PP -Some configurations of the compiler also support additional special -options, usually for compatibility with other compilers on the same -platform. -.PP -These options are defined by the macro \f(CW\*(C`TARGET_SWITCHES\*(C'\fR in the -machine description. The default for the options is also defined by -that macro, which enables you to change the defaults. -.PP -.I "M680x0 Options" -.IX Subsection "M680x0 Options" -.PP -These are the \fB\-m\fR options defined for the 68000 series. The default -values for these options depends on which style of 68000 was selected when -the compiler was configured; the defaults for the most common choices are -given below. -.Ip "\fB\-m68000\fR" 4 -.IX Item "-m68000" -.PD 0 -.Ip "\fB\-mc68000\fR" 4 -.IX Item "-mc68000" -.PD -Generate output for a 68000. This is the default -when the compiler is configured for 68000\-based systems. -.Sp -Use this option for microcontrollers with a 68000 or \s-1EC000\s0 core, -including the 68008, 68302, 68306, 68307, 68322, 68328 and 68356. -.Ip "\fB\-m68020\fR" 4 -.IX Item "-m68020" -.PD 0 -.Ip "\fB\-mc68020\fR" 4 -.IX Item "-mc68020" -.PD -Generate output for a 68020. This is the default -when the compiler is configured for 68020\-based systems. -.Ip "\fB\-m68881\fR" 4 -.IX Item "-m68881" -Generate output containing 68881 instructions for floating point. -This is the default for most 68020 systems unless \fB\*(--nfp\fR was -specified when the compiler was configured. -.Ip "\fB\-m68030\fR" 4 -.IX Item "-m68030" -Generate output for a 68030. This is the default when the compiler is -configured for 68030\-based systems. -.Ip "\fB\-m68040\fR" 4 -.IX Item "-m68040" -Generate output for a 68040. This is the default when the compiler is -configured for 68040\-based systems. -.Sp -This option inhibits the use of 68881/68882 instructions that have to be -emulated by software on the 68040. Use this option if your 68040 does not -have code to emulate those instructions. -.Ip "\fB\-m68060\fR" 4 -.IX Item "-m68060" -Generate output for a 68060. This is the default when the compiler is -configured for 68060\-based systems. -.Sp -This option inhibits the use of 68020 and 68881/68882 instructions that -have to be emulated by software on the 68060. Use this option if your 68060 -does not have code to emulate those instructions. -.Ip "\fB\-mcpu32\fR" 4 -.IX Item "-mcpu32" -Generate output for a \s-1CPU32\s0. This is the default -when the compiler is configured for CPU32\-based systems. -.Sp -Use this option for microcontrollers with a -\&\s-1CPU32\s0 or \s-1CPU32+\s0 core, including the 68330, 68331, 68332, 68333, 68334, -68336, 68340, 68341, 68349 and 68360. -.Ip "\fB\-m5200\fR" 4 -.IX Item "-m5200" -Generate output for a 520X ``coldfire'' family cpu. This is the default -when the compiler is configured for 520X-based systems. -.Sp -Use this option for microcontroller with a 5200 core, including -the \s-1MCF5202\s0, \s-1MCF5203\s0, \s-1MCF5204\s0 and \s-1MCF5202\s0. -.Ip "\fB\-m68020\-40\fR" 4 -.IX Item "-m68020-40" -Generate output for a 68040, without using any of the new instructions. -This results in code which can run relatively efficiently on either a -68020/68881 or a 68030 or a 68040. The generated code does use the -68881 instructions that are emulated on the 68040. -.Ip "\fB\-m68020\-60\fR" 4 -.IX Item "-m68020-60" -Generate output for a 68060, without using any of the new instructions. -This results in code which can run relatively efficiently on either a -68020/68881 or a 68030 or a 68040. The generated code does use the -68881 instructions that are emulated on the 68060. -.Ip "\fB\-mfpa\fR" 4 -.IX Item "-mfpa" -Generate output containing Sun \s-1FPA\s0 instructions for floating point. -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -Generate output containing library calls for floating point. -\&\fBWarning:\fR the requisite libraries are not available for all m68k -targets. Normally the facilities of the machine's usual C compiler are -used, but this can't be done directly in cross-compilation. You must -make your own arrangements to provide suitable library functions for -cross-compilation. The embedded targets \fBm68k-*\-aout\fR and -\&\fBm68k-*\-coff\fR do provide software floating point support. -.Ip "\fB\-mshort\fR" 4 -.IX Item "-mshort" -Consider type \f(CW\*(C`int\*(C'\fR to be 16 bits wide, like \f(CW\*(C`short int\*(C'\fR. -.Ip "\fB\-mnobitfield\fR" 4 -.IX Item "-mnobitfield" -Do not use the bit-field instructions. The \fB\-m68000\fR, \fB\-mcpu32\fR -and \fB\-m5200\fR options imply \fB\-mnobitfield\fR. -.Ip "\fB\-mbitfield\fR" 4 -.IX Item "-mbitfield" -Do use the bit-field instructions. The \fB\-m68020\fR option implies -\&\fB\-mbitfield\fR. This is the default if you use a configuration -designed for a 68020. -.Ip "\fB\-mrtd\fR" 4 -.IX Item "-mrtd" -Use a different function-calling convention, in which functions -that take a fixed number of arguments return with the \f(CW\*(C`rtd\*(C'\fR -instruction, which pops their arguments while returning. This -saves one instruction in the caller since there is no need to pop -the arguments there. -.Sp -This calling convention is incompatible with the one normally -used on Unix, so you cannot use it if you need to call libraries -compiled with the Unix compiler. -.Sp -Also, you must provide function prototypes for all functions that -take variable numbers of arguments (including \f(CW\*(C`printf\*(C'\fR); -otherwise incorrect code will be generated for calls to those -functions. -.Sp -In addition, seriously incorrect code will result if you call a -function with too many arguments. (Normally, extra arguments are -harmlessly ignored.) -.Sp -The \f(CW\*(C`rtd\*(C'\fR instruction is supported by the 68010, 68020, 68030, -68040, 68060 and \s-1CPU32\s0 processors, but not by the 68000 or 5200. -.Ip "\fB\-malign-int\fR" 4 -.IX Item "-malign-int" -.PD 0 -.Ip "\fB\-mno-align-int\fR" 4 -.IX Item "-mno-align-int" -.PD -Control whether \s-1GCC\s0 aligns \f(CW\*(C`int\*(C'\fR, \f(CW\*(C`long\*(C'\fR, \f(CW\*(C`long long\*(C'\fR, -\&\f(CW\*(C`float\*(C'\fR, \f(CW\*(C`double\*(C'\fR, and \f(CW\*(C`long double\*(C'\fR variables on a 32\-bit -boundary (\fB\-malign-int\fR) or a 16\-bit boundary (\fB\-mno-align-int\fR). -Aligning variables on 32\-bit boundaries produces code that runs somewhat -faster on processors with 32\-bit busses at the expense of more memory. -.Sp -\&\fBWarning:\fR if you use the \fB\-malign-int\fR switch, \s-1GCC\s0 will -align structures containing the above types differently than -most published application binary interface specifications for the m68k. -.Ip "\fB\-mpcrel\fR" 4 -.IX Item "-mpcrel" -Use the pc-relative addressing mode of the 68000 directly, instead of -using a global offset table. At present, this option implies \fB\-fpic\fR, -allowing at most a 16\-bit offset for pc-relative addressing. \fB\-fPIC\fR is -not presently supported with \fB\-mpcrel\fR, though this could be supported for -68020 and higher processors. -.Ip "\fB\-mno-strict-align\fR" 4 -.IX Item "-mno-strict-align" -.PD 0 -.Ip "\fB\-mstrict-align\fR" 4 -.IX Item "-mstrict-align" -.PD -Do not (do) assume that unaligned memory references will be handled by -the system. -.PP -.I "M68hc1x Options" -.IX Subsection "M68hc1x Options" -.PP -These are the \fB\-m\fR options defined for the 68hc11 and 68hc12 -microcontrollers. The default values for these options depends on -which style of microcontroller was selected when the compiler was configured; -the defaults for the most common choices are given below. -.Ip "\fB\-m6811\fR" 4 -.IX Item "-m6811" -.PD 0 -.Ip "\fB\-m68hc11\fR" 4 -.IX Item "-m68hc11" -.PD -Generate output for a 68HC11. This is the default -when the compiler is configured for 68HC11\-based systems. -.Ip "\fB\-m6812\fR" 4 -.IX Item "-m6812" -.PD 0 -.Ip "\fB\-m68hc12\fR" 4 -.IX Item "-m68hc12" -.PD -Generate output for a 68HC12. This is the default -when the compiler is configured for 68HC12\-based systems. -.Ip "\fB\-mauto-incdec\fR" 4 -.IX Item "-mauto-incdec" -Enable the use of 68HC12 pre and post auto-increment and auto-decrement -addressing modes. -.Ip "\fB\-mshort\fR" 4 -.IX Item "-mshort" -Consider type \f(CW\*(C`int\*(C'\fR to be 16 bits wide, like \f(CW\*(C`short int\*(C'\fR. -.Ip "\fB\-msoft-reg-count=\fR\fIcount\fR" 4 -.IX Item "-msoft-reg-count=count" -Specify the number of pseudo-soft registers which are used for the -code generation. The maximum number is 32. Using more pseudo-soft -register may or may not result in better code depending on the program. -The default is 4 for 68HC11 and 2 for 68HC12. -.PP -.I "\s-1VAX\s0 Options" -.IX Subsection "VAX Options" -.PP -These \fB\-m\fR options are defined for the \s-1VAX:\s0 -.Ip "\fB\-munix\fR" 4 -.IX Item "-munix" -Do not output certain jump instructions (\f(CW\*(C`aobleq\*(C'\fR and so on) -that the Unix assembler for the \s-1VAX\s0 cannot handle across long -ranges. -.Ip "\fB\-mgnu\fR" 4 -.IX Item "-mgnu" -Do output those jump instructions, on the assumption that you -will assemble with the \s-1GNU\s0 assembler. -.Ip "\fB\-mg\fR" 4 -.IX Item "-mg" -Output code for g-format floating point numbers instead of d-format. -.PP -.I "\s-1SPARC\s0 Options" -.IX Subsection "SPARC Options" -.PP -These \fB\-m\fR switches are supported on the \s-1SPARC:\s0 -.Ip "\fB\-mno-app-regs\fR" 4 -.IX Item "-mno-app-regs" -.PD 0 -.Ip "\fB\-mapp-regs\fR" 4 -.IX Item "-mapp-regs" -.PD -Specify \fB\-mapp-regs\fR to generate output using the global registers -2 through 4, which the \s-1SPARC\s0 \s-1SVR4\s0 \s-1ABI\s0 reserves for applications. This -is the default. -.Sp -To be fully \s-1SVR4\s0 \s-1ABI\s0 compliant at the cost of some performance loss, -specify \fB\-mno-app-regs\fR. You should compile libraries and system -software with this option. -.Ip "\fB\-mfpu\fR" 4 -.IX Item "-mfpu" -.PD 0 -.Ip "\fB\-mhard-float\fR" 4 -.IX Item "-mhard-float" -.PD -Generate output containing floating point instructions. This is the -default. -.Ip "\fB\-mno-fpu\fR" 4 -.IX Item "-mno-fpu" -.PD 0 -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -.PD -Generate output containing library calls for floating point. -\&\fBWarning:\fR the requisite libraries are not available for all \s-1SPARC\s0 -targets. Normally the facilities of the machine's usual C compiler are -used, but this cannot be done directly in cross-compilation. You must make -your own arrangements to provide suitable library functions for -cross-compilation. The embedded targets \fBsparc-*\-aout\fR and -\&\fBsparclite-*\-*\fR do provide software floating point support. -.Sp -\&\fB\-msoft-float\fR changes the calling convention in the output file; -therefore, it is only useful if you compile \fIall\fR of a program with -this option. In particular, you need to compile \fIlibgcc.a\fR, the -library that comes with \s-1GCC\s0, with \fB\-msoft-float\fR in order for -this to work. -.Ip "\fB\-mhard-quad-float\fR" 4 -.IX Item "-mhard-quad-float" -Generate output containing quad-word (long double) floating point -instructions. -.Ip "\fB\-msoft-quad-float\fR" 4 -.IX Item "-msoft-quad-float" -Generate output containing library calls for quad-word (long double) -floating point instructions. The functions called are those specified -in the \s-1SPARC\s0 \s-1ABI\s0. This is the default. -.Sp -As of this writing, there are no sparc implementations that have hardware -support for the quad-word floating point instructions. They all invoke -a trap handler for one of these instructions, and then the trap handler -emulates the effect of the instruction. Because of the trap handler overhead, -this is much slower than calling the \s-1ABI\s0 library routines. Thus the -\&\fB\-msoft-quad-float\fR option is the default. -.Ip "\fB\-mno-flat\fR" 4 -.IX Item "-mno-flat" -.PD 0 -.Ip "\fB\-mflat\fR" 4 -.IX Item "-mflat" -.PD -With \fB\-mflat\fR, the compiler does not generate save/restore instructions -and will use a ``flat'' or single register window calling convention. -This model uses \f(CW%i7\fR as the frame pointer and is compatible with the normal -register window model. Code from either may be intermixed. -The local registers and the input registers (0\*(--5) are still treated as -``call saved'' registers and will be saved on the stack as necessary. -.Sp -With \fB\-mno-flat\fR (the default), the compiler emits save/restore -instructions (except for leaf functions) and is the normal mode of operation. -.Ip "\fB\-mno-unaligned-doubles\fR" 4 -.IX Item "-mno-unaligned-doubles" -.PD 0 -.Ip "\fB\-munaligned-doubles\fR" 4 -.IX Item "-munaligned-doubles" -.PD -Assume that doubles have 8 byte alignment. This is the default. -.Sp -With \fB\-munaligned-doubles\fR, \s-1GCC\s0 assumes that doubles have 8 byte -alignment only if they are contained in another type, or if they have an -absolute address. Otherwise, it assumes they have 4 byte alignment. -Specifying this option avoids some rare compatibility problems with code -generated by other compilers. It is not the default because it results -in a performance loss, especially for floating point code. -.Ip "\fB\-mno-faster-structs\fR" 4 -.IX Item "-mno-faster-structs" -.PD 0 -.Ip "\fB\-mfaster-structs\fR" 4 -.IX Item "-mfaster-structs" -.PD -With \fB\-mfaster-structs\fR, the compiler assumes that structures -should have 8 byte alignment. This enables the use of pairs of -\&\f(CW\*(C`ldd\*(C'\fR and \f(CW\*(C`std\*(C'\fR instructions for copies in structure -assignment, in place of twice as many \f(CW\*(C`ld\*(C'\fR and \f(CW\*(C`st\*(C'\fR pairs. -However, the use of this changed alignment directly violates the Sparc -\&\s-1ABI\s0. Thus, it's intended only for use on targets where the developer -acknowledges that their resulting code will not be directly in line with -the rules of the \s-1ABI\s0. -.Ip "\fB\-mv8\fR" 4 -.IX Item "-mv8" -.PD 0 -.Ip "\fB\-msparclite\fR" 4 -.IX Item "-msparclite" -.PD -These two options select variations on the \s-1SPARC\s0 architecture. -.Sp -By default (unless specifically configured for the Fujitsu SPARClite), -\&\s-1GCC\s0 generates code for the v7 variant of the \s-1SPARC\s0 architecture. -.Sp -\&\fB\-mv8\fR will give you \s-1SPARC\s0 v8 code. The only difference from v7 -code is that the compiler emits the integer multiply and integer -divide instructions which exist in \s-1SPARC\s0 v8 but not in \s-1SPARC\s0 v7. -.Sp -\&\fB\-msparclite\fR will give you SPARClite code. This adds the integer -multiply, integer divide step and scan (\f(CW\*(C`ffs\*(C'\fR) instructions which -exist in SPARClite but not in \s-1SPARC\s0 v7. -.Sp -These options are deprecated and will be deleted in a future \s-1GCC\s0 release. -They have been replaced with \fB\-mcpu=xxx\fR. -.Ip "\fB\-mcypress\fR" 4 -.IX Item "-mcypress" -.PD 0 -.Ip "\fB\-msupersparc\fR" 4 -.IX Item "-msupersparc" -.PD -These two options select the processor for which the code is optimized. -.Sp -With \fB\-mcypress\fR (the default), the compiler optimizes code for the -Cypress \s-1CY7C602\s0 chip, as used in the SparcStation/SparcServer 3xx series. -This is also appropriate for the older SparcStation 1, 2, \s-1IPX\s0 etc. -.Sp -With \fB\-msupersparc\fR the compiler optimizes code for the SuperSparc cpu, as -used in the SparcStation 10, 1000 and 2000 series. This flag also enables use -of the full \s-1SPARC\s0 v8 instruction set. -.Sp -These options are deprecated and will be deleted in a future \s-1GCC\s0 release. -They have been replaced with \fB\-mcpu=xxx\fR. -.Ip "\fB\-mcpu=\fR\fIcpu_type\fR" 4 -.IX Item "-mcpu=cpu_type" -Set the instruction set, register set, and instruction scheduling parameters -for machine type \fIcpu_type\fR. Supported values for \fIcpu_type\fR are -\&\fBv7\fR, \fBcypress\fR, \fBv8\fR, \fBsupersparc\fR, \fBsparclite\fR, -\&\fBhypersparc\fR, \fBsparclite86x\fR, \fBf930\fR, \fBf934\fR, -\&\fBsparclet\fR, \fBtsc701\fR, \fBv9\fR, and \fBultrasparc\fR. -.Sp -Default instruction scheduling parameters are used for values that select -an architecture and not an implementation. These are \fBv7\fR, \fBv8\fR, -\&\fBsparclite\fR, \fBsparclet\fR, \fBv9\fR. -.Sp -Here is a list of each supported architecture and their supported -implementations. -.Sp -.Vb 5 -\& v7: cypress -\& v8: supersparc, hypersparc -\& sparclite: f930, f934, sparclite86x -\& sparclet: tsc701 -\& v9: ultrasparc -.Ve -.Ip "\fB\-mtune=\fR\fIcpu_type\fR" 4 -.IX Item "-mtune=cpu_type" -Set the instruction scheduling parameters for machine type -\&\fIcpu_type\fR, but do not set the instruction set or register set that the -option \fB\-mcpu=\fR\fIcpu_type\fR would. -.Sp -The same values for \fB\-mcpu=\fR\fIcpu_type\fR can be used for -\&\fB\-mtune=\fR\fIcpu_type\fR, but the only useful values are those -that select a particular cpu implementation. Those are \fBcypress\fR, -\&\fBsupersparc\fR, \fBhypersparc\fR, \fBf930\fR, \fBf934\fR, -\&\fBsparclite86x\fR, \fBtsc701\fR, and \fBultrasparc\fR. -.PP -These \fB\-m\fR switches are supported in addition to the above -on the \s-1SPARCLET\s0 processor. -.Ip "\fB\-mlittle-endian\fR" 4 -.IX Item "-mlittle-endian" -Generate code for a processor running in little-endian mode. -.Ip "\fB\-mlive-g0\fR" 4 -.IX Item "-mlive-g0" -Treat register \f(CW\*(C`%g0\*(C'\fR as a normal register. -\&\s-1GCC\s0 will continue to clobber it as necessary but will not assume -it always reads as 0. -.Ip "\fB\-mbroken-saverestore\fR" 4 -.IX Item "-mbroken-saverestore" -Generate code that does not use non-trivial forms of the \f(CW\*(C`save\*(C'\fR and -\&\f(CW\*(C`restore\*(C'\fR instructions. Early versions of the \s-1SPARCLET\s0 processor do -not correctly handle \f(CW\*(C`save\*(C'\fR and \f(CW\*(C`restore\*(C'\fR instructions used with -arguments. They correctly handle them used without arguments. A \f(CW\*(C`save\*(C'\fR -instruction used without arguments increments the current window pointer -but does not allocate a new stack frame. It is assumed that the window -overflow trap handler will properly handle this case as will interrupt -handlers. -.PP -These \fB\-m\fR switches are supported in addition to the above -on \s-1SPARC\s0 V9 processors in 64\-bit environments. -.Ip "\fB\-mlittle-endian\fR" 4 -.IX Item "-mlittle-endian" -Generate code for a processor running in little-endian mode. -.Ip "\fB\-m32\fR" 4 -.IX Item "-m32" -.PD 0 -.Ip "\fB\-m64\fR" 4 -.IX Item "-m64" -.PD -Generate code for a 32\-bit or 64\-bit environment. -The 32\-bit environment sets int, long and pointer to 32 bits. -The 64\-bit environment sets int to 32 bits and long and pointer -to 64 bits. -.Ip "\fB\-mcmodel=medlow\fR" 4 -.IX Item "-mcmodel=medlow" -Generate code for the Medium/Low code model: the program must be linked -in the low 32 bits of the address space. Pointers are 64 bits. -Programs can be statically or dynamically linked. -.Ip "\fB\-mcmodel=medmid\fR" 4 -.IX Item "-mcmodel=medmid" -Generate code for the Medium/Middle code model: the program must be linked -in the low 44 bits of the address space, the text segment must be less than -2G bytes, and data segment must be within 2G of the text segment. -Pointers are 64 bits. -.Ip "\fB\-mcmodel=medany\fR" 4 -.IX Item "-mcmodel=medany" -Generate code for the Medium/Anywhere code model: the program may be linked -anywhere in the address space, the text segment must be less than -2G bytes, and data segment must be within 2G of the text segment. -Pointers are 64 bits. -.Ip "\fB\-mcmodel=embmedany\fR" 4 -.IX Item "-mcmodel=embmedany" -Generate code for the Medium/Anywhere code model for embedded systems: -assume a 32\-bit text and a 32\-bit data segment, both starting anywhere -(determined at link time). Register \f(CW%g4\fR points to the base of the -data segment. Pointers are still 64 bits. -Programs are statically linked, \s-1PIC\s0 is not supported. -.Ip "\fB\-mstack-bias\fR" 4 -.IX Item "-mstack-bias" -.PD 0 -.Ip "\fB\-mno-stack-bias\fR" 4 -.IX Item "-mno-stack-bias" -.PD -With \fB\-mstack-bias\fR, \s-1GCC\s0 assumes that the stack pointer, and -frame pointer if present, are offset by \-2047 which must be added back -when making stack frame references. -Otherwise, assume no such offset is present. -.PP -.I "Convex Options" -.IX Subsection "Convex Options" -.PP -These \fB\-m\fR options are defined for Convex: -.Ip "\fB\-mc1\fR" 4 -.IX Item "-mc1" -Generate output for C1. The code will run on any Convex machine. -The preprocessor symbol \f(CW\*(C`_\|_convex_\|_c1_\|_\*(C'\fR is defined. -.Ip "\fB\-mc2\fR" 4 -.IX Item "-mc2" -Generate output for C2. Uses instructions not available on C1. -Scheduling and other optimizations are chosen for max performance on C2. -The preprocessor symbol \f(CW\*(C`_\|_convex_c2_\|_\*(C'\fR is defined. -.Ip "\fB\-mc32\fR" 4 -.IX Item "-mc32" -Generate output for C32xx. Uses instructions not available on C1. -Scheduling and other optimizations are chosen for max performance on C32. -The preprocessor symbol \f(CW\*(C`_\|_convex_c32_\|_\*(C'\fR is defined. -.Ip "\fB\-mc34\fR" 4 -.IX Item "-mc34" -Generate output for C34xx. Uses instructions not available on C1. -Scheduling and other optimizations are chosen for max performance on C34. -The preprocessor symbol \f(CW\*(C`_\|_convex_c34_\|_\*(C'\fR is defined. -.Ip "\fB\-mc38\fR" 4 -.IX Item "-mc38" -Generate output for C38xx. Uses instructions not available on C1. -Scheduling and other optimizations are chosen for max performance on C38. -The preprocessor symbol \f(CW\*(C`_\|_convex_c38_\|_\*(C'\fR is defined. -.Ip "\fB\-margcount\fR" 4 -.IX Item "-margcount" -Generate code which puts an argument count in the word preceding each -argument list. This is compatible with regular \s-1CC\s0, and a few programs -may need the argument count word. \s-1GDB\s0 and other source-level debuggers -do not need it; this info is in the symbol table. -.Ip "\fB\-mnoargcount\fR" 4 -.IX Item "-mnoargcount" -Omit the argument count word. This is the default. -.Ip "\fB\-mvolatile-cache\fR" 4 -.IX Item "-mvolatile-cache" -Allow volatile references to be cached. This is the default. -.Ip "\fB\-mvolatile-nocache\fR" 4 -.IX Item "-mvolatile-nocache" -Volatile references bypass the data cache, going all the way to memory. -This is only needed for multi-processor code that does not use standard -synchronization instructions. Making non-volatile references to volatile -locations will not necessarily work. -.Ip "\fB\-mlong32\fR" 4 -.IX Item "-mlong32" -Type long is 32 bits, the same as type int. This is the default. -.Ip "\fB\-mlong64\fR" 4 -.IX Item "-mlong64" -Type long is 64 bits, the same as type long long. This option is useless, -because no library support exists for it. -.PP -.I "\s-1AMD29K\s0 Options" -.IX Subsection "AMD29K Options" -.PP -These \fB\-m\fR options are defined for the \s-1AMD\s0 Am29000: -.Ip "\fB\-mdw\fR" 4 -.IX Item "-mdw" -Generate code that assumes the \f(CW\*(C`DW\*(C'\fR bit is set, i.e., that byte and -halfword operations are directly supported by the hardware. This is the -default. -.Ip "\fB\-mndw\fR" 4 -.IX Item "-mndw" -Generate code that assumes the \f(CW\*(C`DW\*(C'\fR bit is not set. -.Ip "\fB\-mbw\fR" 4 -.IX Item "-mbw" -Generate code that assumes the system supports byte and halfword write -operations. This is the default. -.Ip "\fB\-mnbw\fR" 4 -.IX Item "-mnbw" -Generate code that assumes the systems does not support byte and -halfword write operations. \fB\-mnbw\fR implies \fB\-mndw\fR. -.Ip "\fB\-msmall\fR" 4 -.IX Item "-msmall" -Use a small memory model that assumes that all function addresses are -either within a single 256 \s-1KB\s0 segment or at an absolute address of less -than 256k. This allows the \f(CW\*(C`call\*(C'\fR instruction to be used instead -of a \f(CW\*(C`const\*(C'\fR, \f(CW\*(C`consth\*(C'\fR, \f(CW\*(C`calli\*(C'\fR sequence. -.Ip "\fB\-mnormal\fR" 4 -.IX Item "-mnormal" -Use the normal memory model: Generate \f(CW\*(C`call\*(C'\fR instructions only when -calling functions in the same file and \f(CW\*(C`calli\*(C'\fR instructions -otherwise. This works if each file occupies less than 256 \s-1KB\s0 but allows -the entire executable to be larger than 256 \s-1KB\s0. This is the default. -.Ip "\fB\-mlarge\fR" 4 -.IX Item "-mlarge" -Always use \f(CW\*(C`calli\*(C'\fR instructions. Specify this option if you expect -a single file to compile into more than 256 \s-1KB\s0 of code. -.Ip "\fB\-m29050\fR" 4 -.IX Item "-m29050" -Generate code for the Am29050. -.Ip "\fB\-m29000\fR" 4 -.IX Item "-m29000" -Generate code for the Am29000. This is the default. -.Ip "\fB\-mkernel-registers\fR" 4 -.IX Item "-mkernel-registers" -Generate references to registers \f(CW\*(C`gr64\-gr95\*(C'\fR instead of to -registers \f(CW\*(C`gr96\-gr127\*(C'\fR. This option can be used when compiling -kernel code that wants a set of global registers disjoint from that used -by user-mode code. -.Sp -Note that when this option is used, register names in \fB\-f\fR flags -must use the normal, user-mode, names. -.Ip "\fB\-muser-registers\fR" 4 -.IX Item "-muser-registers" -Use the normal set of global registers, \f(CW\*(C`gr96\-gr127\*(C'\fR. This is the -default. -.Ip "\fB\-mstack-check\fR" 4 -.IX Item "-mstack-check" -.PD 0 -.Ip "\fB\-mno-stack-check\fR" 4 -.IX Item "-mno-stack-check" -.PD -Insert (or do not insert) a call to \f(CW\*(C`_\|_msp_check\*(C'\fR after each stack -adjustment. This is often used for kernel code. -.Ip "\fB\-mstorem-bug\fR" 4 -.IX Item "-mstorem-bug" -.PD 0 -.Ip "\fB\-mno-storem-bug\fR" 4 -.IX Item "-mno-storem-bug" -.PD -\&\fB\-mstorem-bug\fR handles 29k processors which cannot handle the -separation of a mtsrim insn and a storem instruction (most 29000 chips -to date, but not the 29050). -.Ip "\fB\-mno-reuse-arg-regs\fR" 4 -.IX Item "-mno-reuse-arg-regs" -.PD 0 -.Ip "\fB\-mreuse-arg-regs\fR" 4 -.IX Item "-mreuse-arg-regs" -.PD -\&\fB\-mno-reuse-arg-regs\fR tells the compiler to only use incoming argument -registers for copying out arguments. This helps detect calling a function -with fewer arguments than it was declared with. -.Ip "\fB\-mno-impure-text\fR" 4 -.IX Item "-mno-impure-text" -.PD 0 -.Ip "\fB\-mimpure-text\fR" 4 -.IX Item "-mimpure-text" -.PD -\&\fB\-mimpure-text\fR, used in addition to \fB\-shared\fR, tells the compiler to -not pass \fB\-assert pure-text\fR to the linker when linking a shared object. -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -Generate output containing library calls for floating point. -\&\fBWarning:\fR the requisite libraries are not part of \s-1GCC\s0. -Normally the facilities of the machine's usual C compiler are used, but -this can't be done directly in cross-compilation. You must make your -own arrangements to provide suitable library functions for -cross-compilation. -.Ip "\fB\-mno-multm\fR" 4 -.IX Item "-mno-multm" -Do not generate multm or multmu instructions. This is useful for some embedded -systems which do not have trap handlers for these instructions. -.PP -.I "\s-1ARM\s0 Options" -.IX Subsection "ARM Options" -.PP -These \fB\-m\fR options are defined for Advanced \s-1RISC\s0 Machines (\s-1ARM\s0) -architectures: -.Ip "\fB\-mapcs-frame\fR" 4 -.IX Item "-mapcs-frame" -Generate a stack frame that is compliant with the \s-1ARM\s0 Procedure Call -Standard for all functions, even if this is not strictly necessary for -correct execution of the code. Specifying \fB\-fomit-frame-pointer\fR -with this option will cause the stack frames not to be generated for -leaf functions. The default is \fB\-mno-apcs-frame\fR. -.Ip "\fB\-mapcs\fR" 4 -.IX Item "-mapcs" -This is a synonym for \fB\-mapcs-frame\fR. -.Ip "\fB\-mapcs-26\fR" 4 -.IX Item "-mapcs-26" -Generate code for a processor running with a 26\-bit program counter, -and conforming to the function calling standards for the \s-1APCS\s0 26\-bit -option. This option replaces the \fB\-m2\fR and \fB\-m3\fR options -of previous releases of the compiler. -.Ip "\fB\-mapcs-32\fR" 4 -.IX Item "-mapcs-32" -Generate code for a processor running with a 32\-bit program counter, -and conforming to the function calling standards for the \s-1APCS\s0 32\-bit -option. This option replaces the \fB\-m6\fR option of previous releases -of the compiler. -.Ip "\fB\-mthumb-interwork\fR" 4 -.IX Item "-mthumb-interwork" -Generate code which supports calling between the \s-1ARM\s0 and Thumb -instruction sets. Without this option the two instruction sets cannot -be reliably used inside one program. The default is -\&\fB\-mno-thumb-interwork\fR, since slightly larger code is generated -when \fB\-mthumb-interwork\fR is specified. -.Ip "\fB\-mno-sched-prolog\fR" 4 -.IX Item "-mno-sched-prolog" -Prevent the reordering of instructions in the function prolog, or the -merging of those instruction with the instructions in the function's -body. This means that all functions will start with a recognizable set -of instructions (or in fact one of a choice from a small set of -different function prologues), and this information can be used to -locate the start if functions inside an executable piece of code. The -default is \fB\-msched-prolog\fR. -.Ip "\fB\-mhard-float\fR" 4 -.IX Item "-mhard-float" -Generate output containing floating point instructions. This is the -default. -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -Generate output containing library calls for floating point. -\&\fBWarning:\fR the requisite libraries are not available for all \s-1ARM\s0 -targets. Normally the facilities of the machine's usual C compiler are -used, but this cannot be done directly in cross-compilation. You must make -your own arrangements to provide suitable library functions for -cross-compilation. -.Sp -\&\fB\-msoft-float\fR changes the calling convention in the output file; -therefore, it is only useful if you compile \fIall\fR of a program with -this option. In particular, you need to compile \fIlibgcc.a\fR, the -library that comes with \s-1GCC\s0, with \fB\-msoft-float\fR in order for -this to work. -.Ip "\fB\-mlittle-endian\fR" 4 -.IX Item "-mlittle-endian" -Generate code for a processor running in little-endian mode. This is -the default for all standard configurations. -.Ip "\fB\-mbig-endian\fR" 4 -.IX Item "-mbig-endian" -Generate code for a processor running in big-endian mode; the default is -to compile code for a little-endian processor. -.Ip "\fB\-mwords-little-endian\fR" 4 -.IX Item "-mwords-little-endian" -This option only applies when generating code for big-endian processors. -Generate code for a little-endian word order but a big-endian byte -order. That is, a byte order of the form \fB32107654\fR. Note: this -option should only be used if you require compatibility with code for -big-endian \s-1ARM\s0 processors generated by versions of the compiler prior to -2.8. -.Ip "\fB\-malignment-traps\fR" 4 -.IX Item "-malignment-traps" -Generate code that will not trap if the \s-1MMU\s0 has alignment traps enabled. -On \s-1ARM\s0 architectures prior to ARMv4, there were no instructions to -access half-word objects stored in memory. However, when reading from -memory a feature of the \s-1ARM\s0 architecture allows a word load to be used, -even if the address is unaligned, and the processor core will rotate the -data as it is being loaded. This option tells the compiler that such -misaligned accesses will cause a \s-1MMU\s0 trap and that it should instead -synthesise the access as a series of byte accesses. The compiler can -still use word accesses to load half-word data if it knows that the -address is aligned to a word boundary. -.Sp -This option is ignored when compiling for \s-1ARM\s0 architecture 4 or later, -since these processors have instructions to directly access half-word -objects in memory. -.Ip "\fB\-mno-alignment-traps\fR" 4 -.IX Item "-mno-alignment-traps" -Generate code that assumes that the \s-1MMU\s0 will not trap unaligned -accesses. This produces better code when the target instruction set -does not have half-word memory operations (i.e. implementations prior to -ARMv4). -.Sp -Note that you cannot use this option to access unaligned word objects, -since the processor will only fetch one 32\-bit aligned object from -memory. -.Sp -The default setting for most targets is \fB\-mno-alignment-traps\fR, since -this produces better code when there are no half-word memory -instructions available. -.Ip "\fB\-mshort-load-bytes\fR" 4 -.IX Item "-mshort-load-bytes" -.PD 0 -.Ip "\fB\-mno-short-load-words\fR" 4 -.IX Item "-mno-short-load-words" -.PD -These are deprecated aliases for \fB\-malignment-traps\fR. -.Ip "\fB\-mno-short-load-bytes\fR" 4 -.IX Item "-mno-short-load-bytes" -.PD 0 -.Ip "\fB\-mshort-load-words\fR" 4 -.IX Item "-mshort-load-words" -.PD -This are deprecated aliases for \fB\-mno-alignment-traps\fR. -.Ip "\fB\-mbsd\fR" 4 -.IX Item "-mbsd" -This option only applies to \s-1RISC\s0 iX. Emulate the native BSD-mode -compiler. This is the default if \fB\-ansi\fR is not specified. -.Ip "\fB\-mxopen\fR" 4 -.IX Item "-mxopen" -This option only applies to \s-1RISC\s0 iX. Emulate the native X/Open-mode -compiler. -.Ip "\fB\-mno-symrename\fR" 4 -.IX Item "-mno-symrename" -This option only applies to \s-1RISC\s0 iX. Do not run the assembler -post-processor, \fBsymrename\fR, after code has been assembled. -Normally it is necessary to modify some of the standard symbols in -preparation for linking with the \s-1RISC\s0 iX C library; this option -suppresses this pass. The post-processor is never run when the -compiler is built for cross-compilation. -.Ip "\fB\-mcpu=\fR\fIname\fR" 4 -.IX Item "-mcpu=name" -This specifies the name of the target \s-1ARM\s0 processor. \s-1GCC\s0 uses this name -to determine what kind of instructions it can emit when generating -assembly code. Permissible names are: \fBarm2\fR, \fBarm250\fR, -\&\fBarm3\fR, \fBarm6\fR, \fBarm60\fR, \fBarm600\fR, \fBarm610\fR, -\&\fBarm620\fR, \fBarm7\fR, \fBarm7m\fR, \fBarm7d\fR, \fBarm7dm\fR, -\&\fBarm7di\fR, \fBarm7dmi\fR, \fBarm70\fR, \fBarm700\fR, -\&\fBarm700i\fR, \fBarm710\fR, \fBarm710c\fR, \fBarm7100\fR, -\&\fBarm7500\fR, \fBarm7500fe\fR, \fBarm7tdmi\fR, \fBarm8\fR, -\&\fBstrongarm\fR, \fBstrongarm110\fR, \fBstrongarm1100\fR, -\&\fBarm8\fR, \fBarm810\fR, \fBarm9\fR, \fBarm9e\fR, \fBarm920\fR, -\&\fBarm920t\fR, \fBarm940t\fR, \fBarm9tdmi\fR, \fBarm10tdmi\fR, -\&\fBarm1020t\fR, \fBxscale\fR. -.Ip "\fB\-mtune=\fR\fIname\fR" 4 -.IX Item "-mtune=name" -This option is very similar to the \fB\-mcpu=\fR option, except that -instead of specifying the actual target processor type, and hence -restricting which instructions can be used, it specifies that \s-1GCC\s0 should -tune the performance of the code as if the target were of the type -specified in this option, but still choosing the instructions that it -will generate based on the cpu specified by a \fB\-mcpu=\fR option. -For some \s-1ARM\s0 implementations better performance can be obtained by using -this option. -.Ip "\fB\-march=\fR\fIname\fR" 4 -.IX Item "-march=name" -This specifies the name of the target \s-1ARM\s0 architecture. \s-1GCC\s0 uses this -name to determine what kind of instructions it can emit when generating -assembly code. This option can be used in conjunction with or instead -of the \fB\-mcpu=\fR option. Permissible names are: \fBarmv2\fR, -\&\fBarmv2a\fR, \fBarmv3\fR, \fBarmv3m\fR, \fBarmv4\fR, \fBarmv4t\fR, -\&\fBarmv5\fR, \fBarmv5t\fR, \fBarmv5te\fR. -.Ip "\fB\-mfpe=\fR\fInumber\fR" 4 -.IX Item "-mfpe=number" -.PD 0 -.Ip "\fB\-mfp=\fR\fInumber\fR" 4 -.IX Item "-mfp=number" -.PD -This specifies the version of the floating point emulation available on -the target. Permissible values are 2 and 3. \fB\-mfp=\fR is a synonym -for \fB\-mfpe=\fR, for compatibility with older versions of \s-1GCC\s0. -.Ip "\fB\-mstructure-size-boundary=\fR\fIn\fR" 4 -.IX Item "-mstructure-size-boundary=n" -The size of all structures and unions will be rounded up to a multiple -of the number of bits set by this option. Permissible values are 8 and -32. The default value varies for different toolchains. For the \s-1COFF\s0 -targeted toolchain the default value is 8. Specifying the larger number -can produce faster, more efficient code, but can also increase the size -of the program. The two values are potentially incompatible. Code -compiled with one value cannot necessarily expect to work with code or -libraries compiled with the other value, if they exchange information -using structures or unions. -.Ip "\fB\-mabort-on-noreturn\fR" 4 -.IX Item "-mabort-on-noreturn" -Generate a call to the function \f(CW\*(C`abort\*(C'\fR at the end of a -\&\f(CW\*(C`noreturn\*(C'\fR function. It will be executed if the function tries to -return. -.Ip "\fB\-mlong-calls\fR" 4 -.IX Item "-mlong-calls" -.PD 0 -.Ip "\fB\-mno-long-calls\fR" 4 -.IX Item "-mno-long-calls" -.PD -Tells the compiler to perform function calls by first loading the -address of the function into a register and then performing a subroutine -call on this register. This switch is needed if the target function -will lie outside of the 64 megabyte addressing range of the offset based -version of subroutine call instruction. -.Sp -Even if this switch is enabled, not all function calls will be turned -into long calls. The heuristic is that static functions, functions -which have the \fBshort-call\fR attribute, functions that are inside -the scope of a \fB#pragma no_long_calls\fR directive and functions whose -definitions have already been compiled within the current compilation -unit, will not be turned into long calls. The exception to this rule is -that weak function definitions, functions with the \fBlong-call\fR -attribute or the \fBsection\fR attribute, and functions that are within -the scope of a \fB#pragma long_calls\fR directive, will always be -turned into long calls. -.Sp -This feature is not enabled by default. Specifying -\&\fB\-mno-long-calls\fR will restore the default behavior, as will -placing the function calls within the scope of a \fB#pragma -long_calls_off\fR directive. Note these switches have no effect on how -the compiler generates code to handle function calls via function -pointers. -.Ip "\fB\-mnop-fun-dllimport\fR" 4 -.IX Item "-mnop-fun-dllimport" -Disable support for the \f(CW\*(C`dllimport\*(C'\fR attribute. -.Ip "\fB\-msingle-pic-base\fR" 4 -.IX Item "-msingle-pic-base" -Treat the register used for \s-1PIC\s0 addressing as read-only, rather than -loading it in the prologue for each function. The run-time system is -responsible for initializing this register with an appropriate value -before execution begins. -.Ip "\fB\-mpic-register=\fR\fIreg\fR" 4 -.IX Item "-mpic-register=reg" -Specify the register to be used for \s-1PIC\s0 addressing. The default is R10 -unless stack-checking is enabled, when R9 is used. -.Ip "\fB\-mpoke-function-name\fR" 4 -.IX Item "-mpoke-function-name" -Write the name of each function into the text section, directly -preceding the function prologue. The generated code is similar to this: -.Sp -.Vb 9 -\& t0 -\& .ascii "arm_poke_function_name", 0 -\& .align -\& t1 -\& .word 0xff000000 + (t1 - t0) -\& arm_poke_function_name -\& mov ip, sp -\& stmfd sp!, {fp, ip, lr, pc} -\& sub fp, ip, #4 -.Ve -When performing a stack backtrace, code can inspect the value of -\&\f(CW\*(C`pc\*(C'\fR stored at \f(CW\*(C`fp + 0\*(C'\fR. If the trace function then looks at -location \f(CW\*(C`pc \- 12\*(C'\fR and the top 8 bits are set, then we know that -there is a function name embedded immediately preceding this location -and has length \f(CW\*(C`((pc[\-3]) & 0xff000000)\*(C'\fR. -.Ip "\fB\-mthumb\fR" 4 -.IX Item "-mthumb" -Generate code for the 16\-bit Thumb instruction set. The default is to -use the 32\-bit \s-1ARM\s0 instruction set. -.Ip "\fB\-mtpcs-frame\fR" 4 -.IX Item "-mtpcs-frame" -Generate a stack frame that is compliant with the Thumb Procedure Call -Standard for all non-leaf functions. (A leaf function is one that does -not call any other functions.) The default is \fB\-mno-tpcs-frame\fR. -.Ip "\fB\-mtpcs-leaf-frame\fR" 4 -.IX Item "-mtpcs-leaf-frame" -Generate a stack frame that is compliant with the Thumb Procedure Call -Standard for all leaf functions. (A leaf function is one that does -not call any other functions.) The default is \fB\-mno-apcs-leaf-frame\fR. -.Ip "\fB\-mcallee-super-interworking\fR" 4 -.IX Item "-mcallee-super-interworking" -Gives all externally visible functions in the file being compiled an \s-1ARM\s0 -instruction set header which switches to Thumb mode before executing the -rest of the function. This allows these functions to be called from -non-interworking code. -.Ip "\fB\-mcaller-super-interworking\fR" 4 -.IX Item "-mcaller-super-interworking" -Allows calls via function pointers (including virtual functions) to -execute correctly regardless of whether the target code has been -compiled for interworking or not. There is a small overhead in the cost -of executing a function pointer if this option is enabled. -.PP -.I "\s-1MN10200\s0 Options" -.IX Subsection "MN10200 Options" -.PP -These \fB\-m\fR options are defined for Matsushita \s-1MN10200\s0 architectures: -.Ip "\fB\-mrelax\fR" 4 -.IX Item "-mrelax" -Indicate to the linker that it should perform a relaxation optimization pass -to shorten branches, calls and absolute memory addresses. This option only -has an effect when used on the command line for the final link step. -.Sp -This option makes symbolic debugging impossible. -.PP -.I "\s-1MN10300\s0 Options" -.IX Subsection "MN10300 Options" -.PP -These \fB\-m\fR options are defined for Matsushita \s-1MN10300\s0 architectures: -.Ip "\fB\-mmult-bug\fR" 4 -.IX Item "-mmult-bug" -Generate code to avoid bugs in the multiply instructions for the \s-1MN10300\s0 -processors. This is the default. -.Ip "\fB\-mno-mult-bug\fR" 4 -.IX Item "-mno-mult-bug" -Do not generate code to avoid bugs in the multiply instructions for the -\&\s-1MN10300\s0 processors. -.Ip "\fB\-mam33\fR" 4 -.IX Item "-mam33" -Generate code which uses features specific to the \s-1AM33\s0 processor. -.Ip "\fB\-mno-am33\fR" 4 -.IX Item "-mno-am33" -Do not generate code which uses features specific to the \s-1AM33\s0 processor. This -is the default. -.Ip "\fB\-mno-crt0\fR" 4 -.IX Item "-mno-crt0" -Do not link in the C run-time initialization object file. -.Ip "\fB\-mrelax\fR" 4 -.IX Item "-mrelax" -Indicate to the linker that it should perform a relaxation optimization pass -to shorten branches, calls and absolute memory addresses. This option only -has an effect when used on the command line for the final link step. -.Sp -This option makes symbolic debugging impossible. -.PP -.I "M32R/D Options" -.IX Subsection "M32R/D Options" -.PP -These \fB\-m\fR options are defined for Mitsubishi M32R/D architectures: -.Ip "\fB\-m32rx\fR" 4 -.IX Item "-m32rx" -Generate code for the M32R/X. -.Ip "\fB\-m32r\fR" 4 -.IX Item "-m32r" -Generate code for the M32R. This is the default. -.Ip "\fB\-mcode-model=small\fR" 4 -.IX Item "-mcode-model=small" -Assume all objects live in the lower 16MB of memory (so that their addresses -can be loaded with the \f(CW\*(C`ld24\*(C'\fR instruction), and assume all subroutines -are reachable with the \f(CW\*(C`bl\*(C'\fR instruction. -This is the default. -.Sp -The addressability of a particular object can be set with the -\&\f(CW\*(C`model\*(C'\fR attribute. -.Ip "\fB\-mcode-model=medium\fR" 4 -.IX Item "-mcode-model=medium" -Assume objects may be anywhere in the 32\-bit address space (the compiler -will generate \f(CW\*(C`seth/add3\*(C'\fR instructions to load their addresses), and -assume all subroutines are reachable with the \f(CW\*(C`bl\*(C'\fR instruction. -.Ip "\fB\-mcode-model=large\fR" 4 -.IX Item "-mcode-model=large" -Assume objects may be anywhere in the 32\-bit address space (the compiler -will generate \f(CW\*(C`seth/add3\*(C'\fR instructions to load their addresses), and -assume subroutines may not be reachable with the \f(CW\*(C`bl\*(C'\fR instruction -(the compiler will generate the much slower \f(CW\*(C`seth/add3/jl\*(C'\fR -instruction sequence). -.Ip "\fB\-msdata=none\fR" 4 -.IX Item "-msdata=none" -Disable use of the small data area. Variables will be put into -one of \fB.data\fR, \fBbss\fR, or \fB.rodata\fR (unless the -\&\f(CW\*(C`section\*(C'\fR attribute has been specified). -This is the default. -.Sp -The small data area consists of sections \fB.sdata\fR and \fB.sbss\fR. -Objects may be explicitly put in the small data area with the -\&\f(CW\*(C`section\*(C'\fR attribute using one of these sections. -.Ip "\fB\-msdata=sdata\fR" 4 -.IX Item "-msdata=sdata" -Put small global and static data in the small data area, but do not -generate special code to reference them. -.Ip "\fB\-msdata=use\fR" 4 -.IX Item "-msdata=use" -Put small global and static data in the small data area, and generate -special instructions to reference them. -.Ip "\fB\-G\fR \fInum\fR" 4 -.IX Item "-G num" -Put global and static objects less than or equal to \fInum\fR bytes -into the small data or bss sections instead of the normal data or bss -sections. The default value of \fInum\fR is 8. -The \fB\-msdata\fR option must be set to one of \fBsdata\fR or \fBuse\fR -for this option to have any effect. -.Sp -All modules should be compiled with the same \fB\-G\fR \fInum\fR value. -Compiling with different values of \fInum\fR may or may not work; if it -doesn't the linker will give an error message\-\-\-incorrect code will not be -generated. -.PP -.I "M88K Options" -.IX Subsection "M88K Options" -.PP -These \fB\-m\fR options are defined for Motorola 88k architectures: -.Ip "\fB\-m88000\fR" 4 -.IX Item "-m88000" -Generate code that works well on both the m88100 and the -m88110. -.Ip "\fB\-m88100\fR" 4 -.IX Item "-m88100" -Generate code that works best for the m88100, but that also -runs on the m88110. -.Ip "\fB\-m88110\fR" 4 -.IX Item "-m88110" -Generate code that works best for the m88110, and may not run -on the m88100. -.Ip "\fB\-mbig-pic\fR" 4 -.IX Item "-mbig-pic" -Obsolete option to be removed from the next revision. -Use \fB\-fPIC\fR. -.Ip "\fB\-midentify-revision\fR" 4 -.IX Item "-midentify-revision" -Include an \f(CW\*(C`ident\*(C'\fR directive in the assembler output recording the -source file name, compiler name and version, timestamp, and compilation -flags used. -.Ip "\fB\-mno-underscores\fR" 4 -.IX Item "-mno-underscores" -In assembler output, emit symbol names without adding an underscore -character at the beginning of each name. The default is to use an -underscore as prefix on each name. -.Ip "\fB\-mocs-debug-info\fR" 4 -.IX Item "-mocs-debug-info" -.PD 0 -.Ip "\fB\-mno-ocs-debug-info\fR" 4 -.IX Item "-mno-ocs-debug-info" -.PD -Include (or omit) additional debugging information (about registers used -in each stack frame) as specified in the 88open Object Compatibility -Standard, ``\s-1OCS\s0''. This extra information allows debugging of code that -has had the frame pointer eliminated. The default for \s-1DG/UX\s0, SVr4, and -Delta 88 SVr3.2 is to include this information; other 88k configurations -omit this information by default. -.Ip "\fB\-mocs-frame-position\fR" 4 -.IX Item "-mocs-frame-position" -When emitting \s-1COFF\s0 debugging information for automatic variables and -parameters stored on the stack, use the offset from the canonical frame -address, which is the stack pointer (register 31) on entry to the -function. The \s-1DG/UX\s0, SVr4, Delta88 SVr3.2, and \s-1BCS\s0 configurations use -\&\fB\-mocs-frame-position\fR; other 88k configurations have the default -\&\fB\-mno-ocs-frame-position\fR. -.Ip "\fB\-mno-ocs-frame-position\fR" 4 -.IX Item "-mno-ocs-frame-position" -When emitting \s-1COFF\s0 debugging information for automatic variables and -parameters stored on the stack, use the offset from the frame pointer -register (register 30). When this option is in effect, the frame -pointer is not eliminated when debugging information is selected by the -\&\-g switch. -.Ip "\fB\-moptimize-arg-area\fR" 4 -.IX Item "-moptimize-arg-area" -Save space by reorganizing the stack frame. This option generates code -that does not agree with the 88open specifications, but uses less -memory. -.Ip "\fB\-mno-optimize-arg-area\fR" 4 -.IX Item "-mno-optimize-arg-area" -Do not reorganize the stack frame to save space. This is the default. -The generated conforms to the specification, but uses more memory. -.Ip "\fB\-mshort-data-\fR\fInum\fR" 4 -.IX Item "-mshort-data-num" -Generate smaller data references by making them relative to \f(CW\*(C`r0\*(C'\fR, -which allows loading a value using a single instruction (rather than the -usual two). You control which data references are affected by -specifying \fInum\fR with this option. For example, if you specify -\&\fB\-mshort-data-512\fR, then the data references affected are those -involving displacements of less than 512 bytes. -\&\fB\-mshort-data-\fR\fInum\fR is not effective for \fInum\fR greater -than 64k. -.Ip "\fB\-mserialize-volatile\fR" 4 -.IX Item "-mserialize-volatile" -.PD 0 -.Ip "\fB\-mno-serialize-volatile\fR" 4 -.IX Item "-mno-serialize-volatile" -.PD -Do, or don't, generate code to guarantee sequential consistency -of volatile memory references. By default, consistency is -guaranteed. -.Sp -The order of memory references made by the \s-1MC88110\s0 processor does -not always match the order of the instructions requesting those -references. In particular, a load instruction may execute before -a preceding store instruction. Such reordering violates -sequential consistency of volatile memory references, when there -are multiple processors. When consistency must be guaranteed, -\&\s-1GCC\s0 generates special instructions, as needed, to force -execution in the proper order. -.Sp -The \s-1MC88100\s0 processor does not reorder memory references and so -always provides sequential consistency. However, by default, \s-1GCC\s0 -generates the special instructions to guarantee consistency -even when you use \fB\-m88100\fR, so that the code may be run on an -\&\s-1MC88110\s0 processor. If you intend to run your code only on the -\&\s-1MC88100\s0 processor, you may use \fB\-mno-serialize-volatile\fR. -.Sp -The extra code generated to guarantee consistency may affect the -performance of your application. If you know that you can safely -forgo this guarantee, you may use \fB\-mno-serialize-volatile\fR. -.Ip "\fB\-msvr4\fR" 4 -.IX Item "-msvr4" -.PD 0 -.Ip "\fB\-msvr3\fR" 4 -.IX Item "-msvr3" -.PD -Turn on (\fB\-msvr4\fR) or off (\fB\-msvr3\fR) compiler extensions -related to System V release 4 (SVr4). This controls the following: -.RS 4 -.Ip "1." 4 -Which variant of the assembler syntax to emit. -.Ip "2." 4 -\&\fB\-msvr4\fR makes the C preprocessor recognize \fB#pragma weak\fR -that is used on System V release 4. -.Ip "3." 4 -\&\fB\-msvr4\fR makes \s-1GCC\s0 issue additional declaration directives used in -SVr4. -.RE -.RS 4 -.Sp -\&\fB\-msvr4\fR is the default for the m88k-motorola-sysv4 and -m88k-dg-dgux m88k configurations. \fB\-msvr3\fR is the default for all -other m88k configurations. -.RE -.Ip "\fB\-mversion-03.00\fR" 4 -.IX Item "-mversion-03.00" -This option is obsolete, and is ignored. -.Ip "\fB\-mno-check-zero-division\fR" 4 -.IX Item "-mno-check-zero-division" -.PD 0 -.Ip "\fB\-mcheck-zero-division\fR" 4 -.IX Item "-mcheck-zero-division" -.PD -Do, or don't, generate code to guarantee that integer division by -zero will be detected. By default, detection is guaranteed. -.Sp -Some models of the \s-1MC88100\s0 processor fail to trap upon integer -division by zero under certain conditions. By default, when -compiling code that might be run on such a processor, \s-1GCC\s0 -generates code that explicitly checks for zero-valued divisors -and traps with exception number 503 when one is detected. Use of -\&\fB\-mno-check-zero-division\fR suppresses such checking for code -generated to run on an \s-1MC88100\s0 processor. -.Sp -\&\s-1GCC\s0 assumes that the \s-1MC88110\s0 processor correctly detects all instances -of integer division by zero. When \fB\-m88110\fR is specified, no -explicit checks for zero-valued divisors are generated, and both -\&\fB\-mcheck-zero-division\fR and \fB\-mno-check-zero-division\fR are -ignored. -.Ip "\fB\-muse-div-instruction\fR" 4 -.IX Item "-muse-div-instruction" -Use the div instruction for signed integer division on the -\&\s-1MC88100\s0 processor. By default, the div instruction is not used. -.Sp -On the \s-1MC88100\s0 processor the signed integer division instruction -div) traps to the operating system on a negative operand. The -operating system transparently completes the operation, but at a -large cost in execution time. By default, when compiling code -that might be run on an \s-1MC88100\s0 processor, \s-1GCC\s0 emulates signed -integer division using the unsigned integer division instruction -divu), thereby avoiding the large penalty of a trap to the -operating system. Such emulation has its own, smaller, execution -cost in both time and space. To the extent that your code's -important signed integer division operations are performed on two -nonnegative operands, it may be desirable to use the div -instruction directly. -.Sp -On the \s-1MC88110\s0 processor the div instruction (also known as the -divs instruction) processes negative operands without trapping to -the operating system. When \fB\-m88110\fR is specified, -\&\fB\-muse-div-instruction\fR is ignored, and the div instruction is used -for signed integer division. -.Sp -Note that the result of dividing \f(CW\*(C`INT_MIN\*(C'\fR by \-1 is undefined. In -particular, the behavior of such a division with and without -\&\fB\-muse-div-instruction\fR may differ. -.Ip "\fB\-mtrap-large-shift\fR" 4 -.IX Item "-mtrap-large-shift" -.PD 0 -.Ip "\fB\-mhandle-large-shift\fR" 4 -.IX Item "-mhandle-large-shift" -.PD -Include code to detect bit-shifts of more than 31 bits; respectively, -trap such shifts or emit code to handle them properly. By default \s-1GCC\s0 -makes no special provision for large bit shifts. -.Ip "\fB\-mwarn-passed-structs\fR" 4 -.IX Item "-mwarn-passed-structs" -Warn when a function passes a struct as an argument or result. -Structure-passing conventions have changed during the evolution of the C -language, and are often the source of portability problems. By default, -\&\s-1GCC\s0 issues no such warning. -.PP -.I "\s-1IBM\s0 \s-1RS/6000\s0 and PowerPC Options" -.IX Subsection "IBM RS/6000 and PowerPC Options" -.PP -These \fB\-m\fR options are defined for the \s-1IBM\s0 \s-1RS/6000\s0 and PowerPC: -.Ip "\fB\-mpower\fR" 4 -.IX Item "-mpower" -.PD 0 -.Ip "\fB\-mno-power\fR" 4 -.IX Item "-mno-power" -.Ip "\fB\-mpower2\fR" 4 -.IX Item "-mpower2" -.Ip "\fB\-mno-power2\fR" 4 -.IX Item "-mno-power2" -.Ip "\fB\-mpowerpc\fR" 4 -.IX Item "-mpowerpc" -.Ip "\fB\-mno-powerpc\fR" 4 -.IX Item "-mno-powerpc" -.Ip "\fB\-mpowerpc-gpopt\fR" 4 -.IX Item "-mpowerpc-gpopt" -.Ip "\fB\-mno-powerpc-gpopt\fR" 4 -.IX Item "-mno-powerpc-gpopt" -.Ip "\fB\-mpowerpc-gfxopt\fR" 4 -.IX Item "-mpowerpc-gfxopt" -.Ip "\fB\-mno-powerpc-gfxopt\fR" 4 -.IX Item "-mno-powerpc-gfxopt" -.Ip "\fB\-mpowerpc64\fR" 4 -.IX Item "-mpowerpc64" -.Ip "\fB\-mno-powerpc64\fR" 4 -.IX Item "-mno-powerpc64" -.PD -\&\s-1GCC\s0 supports two related instruction set architectures for the -\&\s-1RS/6000\s0 and PowerPC. The \fI\s-1POWER\s0\fR instruction set are those -instructions supported by the \fBrios\fR chip set used in the original -\&\s-1RS/6000\s0 systems and the \fIPowerPC\fR instruction set is the -architecture of the Motorola MPC5xx, MPC6xx, MPC8xx microprocessors, and -the \s-1IBM\s0 4xx microprocessors. -.Sp -Neither architecture is a subset of the other. However there is a -large common subset of instructions supported by both. An \s-1MQ\s0 -register is included in processors supporting the \s-1POWER\s0 architecture. -.Sp -You use these options to specify which instructions are available on the -processor you are using. The default value of these options is -determined when configuring \s-1GCC\s0. Specifying the -\&\fB\-mcpu=\fR\fIcpu_type\fR overrides the specification of these -options. We recommend you use the \fB\-mcpu=\fR\fIcpu_type\fR option -rather than the options listed above. -.Sp -The \fB\-mpower\fR option allows \s-1GCC\s0 to generate instructions that -are found only in the \s-1POWER\s0 architecture and to use the \s-1MQ\s0 register. -Specifying \fB\-mpower2\fR implies \fB\-power\fR and also allows \s-1GCC\s0 -to generate instructions that are present in the \s-1POWER2\s0 architecture but -not the original \s-1POWER\s0 architecture. -.Sp -The \fB\-mpowerpc\fR option allows \s-1GCC\s0 to generate instructions that -are found only in the 32\-bit subset of the PowerPC architecture. -Specifying \fB\-mpowerpc-gpopt\fR implies \fB\-mpowerpc\fR and also allows -\&\s-1GCC\s0 to use the optional PowerPC architecture instructions in the -General Purpose group, including floating-point square root. Specifying -\&\fB\-mpowerpc-gfxopt\fR implies \fB\-mpowerpc\fR and also allows \s-1GCC\s0 to -use the optional PowerPC architecture instructions in the Graphics -group, including floating-point select. -.Sp -The \fB\-mpowerpc64\fR option allows \s-1GCC\s0 to generate the additional -64\-bit instructions that are found in the full PowerPC64 architecture -and to treat GPRs as 64\-bit, doubleword quantities. \s-1GCC\s0 defaults to -\&\fB\-mno-powerpc64\fR. -.Sp -If you specify both \fB\-mno-power\fR and \fB\-mno-powerpc\fR, \s-1GCC\s0 -will use only the instructions in the common subset of both -architectures plus some special \s-1AIX\s0 common-mode calls, and will not use -the \s-1MQ\s0 register. Specifying both \fB\-mpower\fR and \fB\-mpowerpc\fR -permits \s-1GCC\s0 to use any instruction from either architecture and to -allow use of the \s-1MQ\s0 register; specify this for the Motorola \s-1MPC601\s0. -.Ip "\fB\-mnew-mnemonics\fR" 4 -.IX Item "-mnew-mnemonics" -.PD 0 -.Ip "\fB\-mold-mnemonics\fR" 4 -.IX Item "-mold-mnemonics" -.PD -Select which mnemonics to use in the generated assembler code. With -\&\fB\-mnew-mnemonics\fR, \s-1GCC\s0 uses the assembler mnemonics defined for -the PowerPC architecture. With \fB\-mold-mnemonics\fR it uses the -assembler mnemonics defined for the \s-1POWER\s0 architecture. Instructions -defined in only one architecture have only one mnemonic; \s-1GCC\s0 uses that -mnemonic irrespective of which of these options is specified. -.Sp -\&\s-1GCC\s0 defaults to the mnemonics appropriate for the architecture in -use. Specifying \fB\-mcpu=\fR\fIcpu_type\fR sometimes overrides the -value of these option. Unless you are building a cross-compiler, you -should normally not specify either \fB\-mnew-mnemonics\fR or -\&\fB\-mold-mnemonics\fR, but should instead accept the default. -.Ip "\fB\-mcpu=\fR\fIcpu_type\fR" 4 -.IX Item "-mcpu=cpu_type" -Set architecture type, register usage, choice of mnemonics, and -instruction scheduling parameters for machine type \fIcpu_type\fR. -Supported values for \fIcpu_type\fR are \fBrios\fR, \fBrios1\fR, -\&\fBrsc\fR, \fBrios2\fR, \fBrs64a\fR, \fB601\fR, \fB602\fR, -\&\fB603\fR, \fB603e\fR, \fB604\fR, \fB604e\fR, \fB620\fR, -\&\fB630\fR, \fB740\fR, \fB7400\fR, \fB7450\fR, \fB750\fR, -\&\fBpower\fR, \fBpower2\fR, \fBpowerpc\fR, \fB403\fR, \fB505\fR, -\&\fB801\fR, \fB821\fR, \fB823\fR, and \fB860\fR and \fBcommon\fR. -.Sp -\&\fB\-mcpu=common\fR selects a completely generic processor. Code -generated under this option will run on any \s-1POWER\s0 or PowerPC processor. -\&\s-1GCC\s0 will use only the instructions in the common subset of both -architectures, and will not use the \s-1MQ\s0 register. \s-1GCC\s0 assumes a generic -processor model for scheduling purposes. -.Sp -\&\fB\-mcpu=power\fR, \fB\-mcpu=power2\fR, \fB\-mcpu=powerpc\fR, and -\&\fB\-mcpu=powerpc64\fR specify generic \s-1POWER\s0, \s-1POWER2\s0, pure 32\-bit -PowerPC (i.e., not \s-1MPC601\s0), and 64\-bit PowerPC architecture machine -types, with an appropriate, generic processor model assumed for -scheduling purposes. -.Sp -The other options specify a specific processor. Code generated under -those options will run best on that processor, and may not run at all on -others. -.Sp -The \fB\-mcpu\fR options automatically enable or disable other -\&\fB\-m\fR options as follows: -.RS 4 -.Ip "\fBcommon\fR" 4 -.IX Item "common" -\&\fB\-mno-power\fR, \fB\-mno-powerc\fR -.Ip "\fBpower\fR" 4 -.IX Item "power" -.PD 0 -.Ip "\fBpower2\fR" 4 -.IX Item "power2" -.Ip "\fBrios1\fR" 4 -.IX Item "rios1" -.Ip "\fBrios2\fR" 4 -.IX Item "rios2" -.Ip "\fBrsc\fR" 4 -.IX Item "rsc" -.PD -\&\fB\-mpower\fR, \fB\-mno-powerpc\fR, \fB\-mno-new-mnemonics\fR -.Ip "\fBpowerpc\fR" 4 -.IX Item "powerpc" -.PD 0 -.Ip "\fBrs64a\fR" 4 -.IX Item "rs64a" -.Ip "\fB602\fR" 4 -.IX Item "602" -.Ip "\fB603\fR" 4 -.IX Item "603" -.Ip "\fB603e\fR" 4 -.IX Item "603e" -.Ip "\fB604\fR" 4 -.IX Item "604" -.Ip "\fB620\fR" 4 -.IX Item "620" -.Ip "\fB630\fR" 4 -.IX Item "630" -.Ip "\fB740\fR" 4 -.IX Item "740" -.Ip "\fB7400\fR" 4 -.IX Item "7400" -.Ip "\fB7450\fR" 4 -.IX Item "7450" -.Ip "\fB750\fR" 4 -.IX Item "750" -.Ip "\fB505\fR" 4 -.IX Item "505" -.PD -\&\fB\-mno-power\fR, \fB\-mpowerpc\fR, \fB\-mnew-mnemonics\fR -.Ip "\fB601\fR" 4 -.IX Item "601" -\&\fB\-mpower\fR, \fB\-mpowerpc\fR, \fB\-mnew-mnemonics\fR -.Ip "\fB403\fR" 4 -.IX Item "403" -.PD 0 -.Ip "\fB821\fR" 4 -.IX Item "821" -.Ip "\fB860\fR" 4 -.IX Item "860" -.PD -\&\fB\-mno-power\fR, \fB\-mpowerpc\fR, \fB\-mnew-mnemonics\fR, \fB\-msoft-float\fR -.RE -.RS 4 -.RE -.Ip "\fB\-mtune=\fR\fIcpu_type\fR" 4 -.IX Item "-mtune=cpu_type" -Set the instruction scheduling parameters for machine type -\&\fIcpu_type\fR, but do not set the architecture type, register usage, or -choice of mnemonics, as \fB\-mcpu=\fR\fIcpu_type\fR would. The same -values for \fIcpu_type\fR are used for \fB\-mtune\fR as for -\&\fB\-mcpu\fR. If both are specified, the code generated will use the -architecture, registers, and mnemonics set by \fB\-mcpu\fR, but the -scheduling parameters set by \fB\-mtune\fR. -.Ip "\fB\-maltivec\fR" 4 -.IX Item "-maltivec" -.PD 0 -.Ip "\fB\-mno-altivec\fR" 4 -.IX Item "-mno-altivec" -.PD -These switches enable or disable the use of built-in functions that -allow access to the AltiVec instruction set. You may also need to set -\&\fB\-mabi=altivec\fR to adjust the current \s-1ABI\s0 with AltiVec \s-1ABI\s0 -enhancements. -.Ip "\fB\-mfull-toc\fR" 4 -.IX Item "-mfull-toc" -.PD 0 -.Ip "\fB\-mno-fp-in-toc\fR" 4 -.IX Item "-mno-fp-in-toc" -.Ip "\fB\-mno-sum-in-toc\fR" 4 -.IX Item "-mno-sum-in-toc" -.Ip "\fB\-mminimal-toc\fR" 4 -.IX Item "-mminimal-toc" -.PD -Modify generation of the \s-1TOC\s0 (Table Of Contents), which is created for -every executable file. The \fB\-mfull-toc\fR option is selected by -default. In that case, \s-1GCC\s0 will allocate at least one \s-1TOC\s0 entry for -each unique non-automatic variable reference in your program. \s-1GCC\s0 -will also place floating-point constants in the \s-1TOC\s0. However, only -16,384 entries are available in the \s-1TOC\s0. -.Sp -If you receive a linker error message that saying you have overflowed -the available \s-1TOC\s0 space, you can reduce the amount of \s-1TOC\s0 space used -with the \fB\-mno-fp-in-toc\fR and \fB\-mno-sum-in-toc\fR options. -\&\fB\-mno-fp-in-toc\fR prevents \s-1GCC\s0 from putting floating-point -constants in the \s-1TOC\s0 and \fB\-mno-sum-in-toc\fR forces \s-1GCC\s0 to -generate code to calculate the sum of an address and a constant at -run-time instead of putting that sum into the \s-1TOC\s0. You may specify one -or both of these options. Each causes \s-1GCC\s0 to produce very slightly -slower and larger code at the expense of conserving \s-1TOC\s0 space. -.Sp -If you still run out of space in the \s-1TOC\s0 even when you specify both of -these options, specify \fB\-mminimal-toc\fR instead. This option causes -\&\s-1GCC\s0 to make only one \s-1TOC\s0 entry for every file. When you specify this -option, \s-1GCC\s0 will produce code that is slower and larger but which -uses extremely little \s-1TOC\s0 space. You may wish to use this option -only on files that contain less frequently executed code. -.Ip "\fB\-maix64\fR" 4 -.IX Item "-maix64" -.PD 0 -.Ip "\fB\-maix32\fR" 4 -.IX Item "-maix32" -.PD -Enable 64\-bit \s-1AIX\s0 \s-1ABI\s0 and calling convention: 64\-bit pointers, 64\-bit -\&\f(CW\*(C`long\*(C'\fR type, and the infrastructure needed to support them. -Specifying \fB\-maix64\fR implies \fB\-mpowerpc64\fR and -\&\fB\-mpowerpc\fR, while \fB\-maix32\fR disables the 64\-bit \s-1ABI\s0 and -implies \fB\-mno-powerpc64\fR. \s-1GCC\s0 defaults to \fB\-maix32\fR. -.Ip "\fB\-mxl-call\fR" 4 -.IX Item "-mxl-call" -.PD 0 -.Ip "\fB\-mno-xl-call\fR" 4 -.IX Item "-mno-xl-call" -.PD -On \s-1AIX\s0, pass floating-point arguments to prototyped functions beyond the -register save area (\s-1RSA\s0) on the stack in addition to argument FPRs. The -\&\s-1AIX\s0 calling convention was extended but not initially documented to -handle an obscure K&R C case of calling a function that takes the -address of its arguments with fewer arguments than declared. \s-1AIX\s0 \s-1XL\s0 -compilers access floating point arguments which do not fit in the -\&\s-1RSA\s0 from the stack when a subroutine is compiled without -optimization. Because always storing floating-point arguments on the -stack is inefficient and rarely needed, this option is not enabled by -default and only is necessary when calling subroutines compiled by \s-1AIX\s0 -\&\s-1XL\s0 compilers without optimization. -.Ip "\fB\-mpe\fR" 4 -.IX Item "-mpe" -Support \fI\s-1IBM\s0 \s-1RS/6000\s0 \s-1SP\s0\fR \fIParallel Environment\fR (\s-1PE\s0). Link an -application written to use message passing with special startup code to -enable the application to run. The system must have \s-1PE\s0 installed in the -standard location (\fI/usr/lpp/ppe.poe/\fR), or the \fIspecs\fR file -must be overridden with the \fB\-specs=\fR option to specify the -appropriate directory location. The Parallel Environment does not -support threads, so the \fB\-mpe\fR option and the \fB\-pthread\fR -option are incompatible. -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -.PD 0 -.Ip "\fB\-mhard-float\fR" 4 -.IX Item "-mhard-float" -.PD -Generate code that does not use (uses) the floating-point register set. -Software floating point emulation is provided if you use the -\&\fB\-msoft-float\fR option, and pass the option to \s-1GCC\s0 when linking. -.Ip "\fB\-mmultiple\fR" 4 -.IX Item "-mmultiple" -.PD 0 -.Ip "\fB\-mno-multiple\fR" 4 -.IX Item "-mno-multiple" -.PD -Generate code that uses (does not use) the load multiple word -instructions and the store multiple word instructions. These -instructions are generated by default on \s-1POWER\s0 systems, and not -generated on PowerPC systems. Do not use \fB\-mmultiple\fR on little -endian PowerPC systems, since those instructions do not work when the -processor is in little endian mode. The exceptions are \s-1PPC740\s0 and -\&\s-1PPC750\s0 which permit the instructions usage in little endian mode. -.Ip "\fB\-mstring\fR" 4 -.IX Item "-mstring" -.PD 0 -.Ip "\fB\-mno-string\fR" 4 -.IX Item "-mno-string" -.PD -Generate code that uses (does not use) the load string instructions -and the store string word instructions to save multiple registers and -do small block moves. These instructions are generated by default on -\&\s-1POWER\s0 systems, and not generated on PowerPC systems. Do not use -\&\fB\-mstring\fR on little endian PowerPC systems, since those -instructions do not work when the processor is in little endian mode. -The exceptions are \s-1PPC740\s0 and \s-1PPC750\s0 which permit the instructions -usage in little endian mode. -.Ip "\fB\-mupdate\fR" 4 -.IX Item "-mupdate" -.PD 0 -.Ip "\fB\-mno-update\fR" 4 -.IX Item "-mno-update" -.PD -Generate code that uses (does not use) the load or store instructions -that update the base register to the address of the calculated memory -location. These instructions are generated by default. If you use -\&\fB\-mno-update\fR, there is a small window between the time that the -stack pointer is updated and the address of the previous frame is -stored, which means code that walks the stack frame across interrupts or -signals may get corrupted data. -.Ip "\fB\-mfused-madd\fR" 4 -.IX Item "-mfused-madd" -.PD 0 -.Ip "\fB\-mno-fused-madd\fR" 4 -.IX Item "-mno-fused-madd" -.PD -Generate code that uses (does not use) the floating point multiply and -accumulate instructions. These instructions are generated by default if -hardware floating is used. -.Ip "\fB\-mno-bit-align\fR" 4 -.IX Item "-mno-bit-align" -.PD 0 -.Ip "\fB\-mbit-align\fR" 4 -.IX Item "-mbit-align" -.PD -On System V.4 and embedded PowerPC systems do not (do) force structures -and unions that contain bit-fields to be aligned to the base type of the -bit-field. -.Sp -For example, by default a structure containing nothing but 8 -\&\f(CW\*(C`unsigned\*(C'\fR bit-fields of length 1 would be aligned to a 4 byte -boundary and have a size of 4 bytes. By using \fB\-mno-bit-align\fR, -the structure would be aligned to a 1 byte boundary and be one byte in -size. -.Ip "\fB\-mno-strict-align\fR" 4 -.IX Item "-mno-strict-align" -.PD 0 -.Ip "\fB\-mstrict-align\fR" 4 -.IX Item "-mstrict-align" -.PD -On System V.4 and embedded PowerPC systems do not (do) assume that -unaligned memory references will be handled by the system. -.Ip "\fB\-mrelocatable\fR" 4 -.IX Item "-mrelocatable" -.PD 0 -.Ip "\fB\-mno-relocatable\fR" 4 -.IX Item "-mno-relocatable" -.PD -On embedded PowerPC systems generate code that allows (does not allow) -the program to be relocated to a different address at runtime. If you -use \fB\-mrelocatable\fR on any module, all objects linked together must -be compiled with \fB\-mrelocatable\fR or \fB\-mrelocatable-lib\fR. -.Ip "\fB\-mrelocatable-lib\fR" 4 -.IX Item "-mrelocatable-lib" -.PD 0 -.Ip "\fB\-mno-relocatable-lib\fR" 4 -.IX Item "-mno-relocatable-lib" -.PD -On embedded PowerPC systems generate code that allows (does not allow) -the program to be relocated to a different address at runtime. Modules -compiled with \fB\-mrelocatable-lib\fR can be linked with either modules -compiled without \fB\-mrelocatable\fR and \fB\-mrelocatable-lib\fR or -with modules compiled with the \fB\-mrelocatable\fR options. -.Ip "\fB\-mno-toc\fR" 4 -.IX Item "-mno-toc" -.PD 0 -.Ip "\fB\-mtoc\fR" 4 -.IX Item "-mtoc" -.PD -On System V.4 and embedded PowerPC systems do not (do) assume that -register 2 contains a pointer to a global area pointing to the addresses -used in the program. -.Ip "\fB\-mlittle\fR" 4 -.IX Item "-mlittle" -.PD 0 -.Ip "\fB\-mlittle-endian\fR" 4 -.IX Item "-mlittle-endian" -.PD -On System V.4 and embedded PowerPC systems compile code for the -processor in little endian mode. The \fB\-mlittle-endian\fR option is -the same as \fB\-mlittle\fR. -.Ip "\fB\-mbig\fR" 4 -.IX Item "-mbig" -.PD 0 -.Ip "\fB\-mbig-endian\fR" 4 -.IX Item "-mbig-endian" -.PD -On System V.4 and embedded PowerPC systems compile code for the -processor in big endian mode. The \fB\-mbig-endian\fR option is -the same as \fB\-mbig\fR. -.Ip "\fB\-mcall-sysv\fR" 4 -.IX Item "-mcall-sysv" -On System V.4 and embedded PowerPC systems compile code using calling -conventions that adheres to the March 1995 draft of the System V -Application Binary Interface, PowerPC processor supplement. This is the -default unless you configured \s-1GCC\s0 using \fBpowerpc-*\-eabiaix\fR. -.Ip "\fB\-mcall-sysv-eabi\fR" 4 -.IX Item "-mcall-sysv-eabi" -Specify both \fB\-mcall-sysv\fR and \fB\-meabi\fR options. -.Ip "\fB\-mcall-sysv-noeabi\fR" 4 -.IX Item "-mcall-sysv-noeabi" -Specify both \fB\-mcall-sysv\fR and \fB\-mno-eabi\fR options. -.Ip "\fB\-mcall-aix\fR" 4 -.IX Item "-mcall-aix" -On System V.4 and embedded PowerPC systems compile code using calling -conventions that are similar to those used on \s-1AIX\s0. This is the -default if you configured \s-1GCC\s0 using \fBpowerpc-*\-eabiaix\fR. -.Ip "\fB\-mcall-solaris\fR" 4 -.IX Item "-mcall-solaris" -On System V.4 and embedded PowerPC systems compile code for the Solaris -operating system. -.Ip "\fB\-mcall-linux\fR" 4 -.IX Item "-mcall-linux" -On System V.4 and embedded PowerPC systems compile code for the -Linux-based \s-1GNU\s0 system. -.Ip "\fB\-mcall-gnu\fR" 4 -.IX Item "-mcall-gnu" -On System V.4 and embedded PowerPC systems compile code for the -Hurd-based \s-1GNU\s0 system. -.Ip "\fB\-mcall-netbsd\fR" 4 -.IX Item "-mcall-netbsd" -On System V.4 and embedded PowerPC systems compile code for the -NetBSD operating system. -.Ip "\fB\-maix-struct-return\fR" 4 -.IX Item "-maix-struct-return" -Return all structures in memory (as specified by the \s-1AIX\s0 \s-1ABI\s0). -.Ip "\fB\-msvr4\-struct-return\fR" 4 -.IX Item "-msvr4-struct-return" -Return structures smaller than 8 bytes in registers (as specified by the -\&\s-1SVR4\s0 \s-1ABI\s0). -.Ip "\fB\-mabi=altivec\fR" 4 -.IX Item "-mabi=altivec" -Extend the current \s-1ABI\s0 with AltiVec \s-1ABI\s0 extensions. This does not -change the default \s-1ABI\s0, instead it adds the AltiVec \s-1ABI\s0 extensions to -the current \s-1ABI\s0. -.Ip "\fB\-mabi=no-altivec\fR" 4 -.IX Item "-mabi=no-altivec" -Disable AltiVec \s-1ABI\s0 extensions for the current \s-1ABI\s0. -.Ip "\fB\-mprototype\fR" 4 -.IX Item "-mprototype" -.PD 0 -.Ip "\fB\-mno-prototype\fR" 4 -.IX Item "-mno-prototype" -.PD -On System V.4 and embedded PowerPC systems assume that all calls to -variable argument functions are properly prototyped. Otherwise, the -compiler must insert an instruction before every non prototyped call to -set or clear bit 6 of the condition code register (\fI\s-1CR\s0\fR) to -indicate whether floating point values were passed in the floating point -registers in case the function takes a variable arguments. With -\&\fB\-mprototype\fR, only calls to prototyped variable argument functions -will set or clear the bit. -.Ip "\fB\-msim\fR" 4 -.IX Item "-msim" -On embedded PowerPC systems, assume that the startup module is called -\&\fIsim-crt0.o\fR and that the standard C libraries are \fIlibsim.a\fR and -\&\fIlibc.a\fR. This is the default for \fBpowerpc-*\-eabisim\fR. -configurations. -.Ip "\fB\-mmvme\fR" 4 -.IX Item "-mmvme" -On embedded PowerPC systems, assume that the startup module is called -\&\fIcrt0.o\fR and the standard C libraries are \fIlibmvme.a\fR and -\&\fIlibc.a\fR. -.Ip "\fB\-mads\fR" 4 -.IX Item "-mads" -On embedded PowerPC systems, assume that the startup module is called -\&\fIcrt0.o\fR and the standard C libraries are \fIlibads.a\fR and -\&\fIlibc.a\fR. -.Ip "\fB\-myellowknife\fR" 4 -.IX Item "-myellowknife" -On embedded PowerPC systems, assume that the startup module is called -\&\fIcrt0.o\fR and the standard C libraries are \fIlibyk.a\fR and -\&\fIlibc.a\fR. -.Ip "\fB\-mvxworks\fR" 4 -.IX Item "-mvxworks" -On System V.4 and embedded PowerPC systems, specify that you are -compiling for a VxWorks system. -.Ip "\fB\-memb\fR" 4 -.IX Item "-memb" -On embedded PowerPC systems, set the \fI\s-1PPC_EMB\s0\fR bit in the \s-1ELF\s0 flags -header to indicate that \fBeabi\fR extended relocations are used. -.Ip "\fB\-meabi\fR" 4 -.IX Item "-meabi" -.PD 0 -.Ip "\fB\-mno-eabi\fR" 4 -.IX Item "-mno-eabi" -.PD -On System V.4 and embedded PowerPC systems do (do not) adhere to the -Embedded Applications Binary Interface (eabi) which is a set of -modifications to the System V.4 specifications. Selecting \fB\-meabi\fR -means that the stack is aligned to an 8 byte boundary, a function -\&\f(CW\*(C`_\|_eabi\*(C'\fR is called to from \f(CW\*(C`main\*(C'\fR to set up the eabi -environment, and the \fB\-msdata\fR option can use both \f(CW\*(C`r2\*(C'\fR and -\&\f(CW\*(C`r13\*(C'\fR to point to two separate small data areas. Selecting -\&\fB\-mno-eabi\fR means that the stack is aligned to a 16 byte boundary, -do not call an initialization function from \f(CW\*(C`main\*(C'\fR, and the -\&\fB\-msdata\fR option will only use \f(CW\*(C`r13\*(C'\fR to point to a single -small data area. The \fB\-meabi\fR option is on by default if you -configured \s-1GCC\s0 using one of the \fBpowerpc*\-*\-eabi*\fR options. -.Ip "\fB\-msdata=eabi\fR" 4 -.IX Item "-msdata=eabi" -On System V.4 and embedded PowerPC systems, put small initialized -\&\f(CW\*(C`const\*(C'\fR global and static data in the \fB.sdata2\fR section, which -is pointed to by register \f(CW\*(C`r2\*(C'\fR. Put small initialized -non-\f(CW\*(C`const\*(C'\fR global and static data in the \fB.sdata\fR section, -which is pointed to by register \f(CW\*(C`r13\*(C'\fR. Put small uninitialized -global and static data in the \fB.sbss\fR section, which is adjacent to -the \fB.sdata\fR section. The \fB\-msdata=eabi\fR option is -incompatible with the \fB\-mrelocatable\fR option. The -\&\fB\-msdata=eabi\fR option also sets the \fB\-memb\fR option. -.Ip "\fB\-msdata=sysv\fR" 4 -.IX Item "-msdata=sysv" -On System V.4 and embedded PowerPC systems, put small global and static -data in the \fB.sdata\fR section, which is pointed to by register -\&\f(CW\*(C`r13\*(C'\fR. Put small uninitialized global and static data in the -\&\fB.sbss\fR section, which is adjacent to the \fB.sdata\fR section. -The \fB\-msdata=sysv\fR option is incompatible with the -\&\fB\-mrelocatable\fR option. -.Ip "\fB\-msdata=default\fR" 4 -.IX Item "-msdata=default" -.PD 0 -.Ip "\fB\-msdata\fR" 4 -.IX Item "-msdata" -.PD -On System V.4 and embedded PowerPC systems, if \fB\-meabi\fR is used, -compile code the same as \fB\-msdata=eabi\fR, otherwise compile code the -same as \fB\-msdata=sysv\fR. -.Ip "\fB\-msdata-data\fR" 4 -.IX Item "-msdata-data" -On System V.4 and embedded PowerPC systems, put small global and static -data in the \fB.sdata\fR section. Put small uninitialized global and -static data in the \fB.sbss\fR section. Do not use register \f(CW\*(C`r13\*(C'\fR -to address small data however. This is the default behavior unless -other \fB\-msdata\fR options are used. -.Ip "\fB\-msdata=none\fR" 4 -.IX Item "-msdata=none" -.PD 0 -.Ip "\fB\-mno-sdata\fR" 4 -.IX Item "-mno-sdata" -.PD -On embedded PowerPC systems, put all initialized global and static data -in the \fB.data\fR section, and all uninitialized data in the -\&\fB.bss\fR section. -.Ip "\fB\-G\fR \fInum\fR" 4 -.IX Item "-G num" -On embedded PowerPC systems, put global and static items less than or -equal to \fInum\fR bytes into the small data or bss sections instead of -the normal data or bss section. By default, \fInum\fR is 8. The -\&\fB\-G\fR \fInum\fR switch is also passed to the linker. -All modules should be compiled with the same \fB\-G\fR \fInum\fR value. -.Ip "\fB\-mregnames\fR" 4 -.IX Item "-mregnames" -.PD 0 -.Ip "\fB\-mno-regnames\fR" 4 -.IX Item "-mno-regnames" -.PD -On System V.4 and embedded PowerPC systems do (do not) emit register -names in the assembly language output using symbolic forms. -.Ip "\fB\-pthread\fR" 4 -.IX Item "-pthread" -Adds support for multithreading with the \fIpthreads\fR library. -This option sets flags for both the preprocessor and linker. -.PP -.I "\s-1IBM\s0 \s-1RT\s0 Options" -.IX Subsection "IBM RT Options" -.PP -These \fB\-m\fR options are defined for the \s-1IBM\s0 \s-1RT\s0 \s-1PC:\s0 -.Ip "\fB\-min-line-mul\fR" 4 -.IX Item "-min-line-mul" -Use an in-line code sequence for integer multiplies. This is the -default. -.Ip "\fB\-mcall-lib-mul\fR" 4 -.IX Item "-mcall-lib-mul" -Call \f(CW\*(C`lmul$$\*(C'\fR for integer multiples. -.Ip "\fB\-mfull-fp-blocks\fR" 4 -.IX Item "-mfull-fp-blocks" -Generate full-size floating point data blocks, including the minimum -amount of scratch space recommended by \s-1IBM\s0. This is the default. -.Ip "\fB\-mminimum-fp-blocks\fR" 4 -.IX Item "-mminimum-fp-blocks" -Do not include extra scratch space in floating point data blocks. This -results in smaller code, but slower execution, since scratch space must -be allocated dynamically. -.Ip "\fB\-mfp-arg-in-fpregs\fR" 4 -.IX Item "-mfp-arg-in-fpregs" -Use a calling sequence incompatible with the \s-1IBM\s0 calling convention in -which floating point arguments are passed in floating point registers. -Note that \f(CW\*(C`varargs.h\*(C'\fR and \f(CW\*(C`stdarg.h\*(C'\fR will not work with -floating point operands if this option is specified. -.Ip "\fB\-mfp-arg-in-gregs\fR" 4 -.IX Item "-mfp-arg-in-gregs" -Use the normal calling convention for floating point arguments. This is -the default. -.Ip "\fB\-mhc-struct-return\fR" 4 -.IX Item "-mhc-struct-return" -Return structures of more than one word in memory, rather than in a -register. This provides compatibility with the MetaWare HighC (hc) -compiler. Use the option \fB\-fpcc-struct-return\fR for compatibility -with the Portable C Compiler (pcc). -.Ip "\fB\-mnohc-struct-return\fR" 4 -.IX Item "-mnohc-struct-return" -Return some structures of more than one word in registers, when -convenient. This is the default. For compatibility with the -IBM-supplied compilers, use the option \fB\-fpcc-struct-return\fR or the -option \fB\-mhc-struct-return\fR. -.PP -.I "\s-1MIPS\s0 Options" -.IX Subsection "MIPS Options" -.PP -These \fB\-m\fR options are defined for the \s-1MIPS\s0 family of computers: -.Ip "\fB\-march=\fR\fIcpu-type\fR" 4 -.IX Item "-march=cpu-type" -Assume the defaults for the machine type \fIcpu-type\fR when generating -instructions. The choices for \fIcpu-type\fR are \fBr2000\fR, \fBr3000\fR, -\&\fBr3900\fR, \fBr4000\fR, \fBr4100\fR, \fBr4300\fR, \fBr4400\fR, -\&\fBr4600\fR, \fBr4650\fR, \fBr5000\fR, \fBr6000\fR, \fBr8000\fR, -and \fBorion\fR. Additionally, the \fBr2000\fR, \fBr3000\fR, -\&\fBr4000\fR, \fBr5000\fR, and \fBr6000\fR can be abbreviated as -\&\fBr2k\fR (or \fBr2K\fR), \fBr3k\fR, etc. -.Ip "\fB\-mtune=\fR\fIcpu-type\fR" 4 -.IX Item "-mtune=cpu-type" -Assume the defaults for the machine type \fIcpu-type\fR when scheduling -instructions. The choices for \fIcpu-type\fR are \fBr2000\fR, \fBr3000\fR, -\&\fBr3900\fR, \fBr4000\fR, \fBr4100\fR, \fBr4300\fR, \fBr4400\fR, -\&\fBr4600\fR, \fBr4650\fR, \fBr5000\fR, \fBr6000\fR, \fBr8000\fR, -and \fBorion\fR. Additionally, the \fBr2000\fR, \fBr3000\fR, -\&\fBr4000\fR, \fBr5000\fR, and \fBr6000\fR can be abbreviated as -\&\fBr2k\fR (or \fBr2K\fR), \fBr3k\fR, etc. While picking a specific -\&\fIcpu-type\fR will schedule things appropriately for that particular -chip, the compiler will not generate any code that does not meet level 1 -of the \s-1MIPS\s0 \s-1ISA\s0 (instruction set architecture) without a \fB\-mipsX\fR -or \fB\-mabi\fR switch being used. -.Ip "\fB\-mcpu=\fR\fIcpu-type\fR" 4 -.IX Item "-mcpu=cpu-type" -This is identical to specifying both \fB\-march\fR and \fB\-mtune\fR. -.Ip "\fB\-mips1\fR" 4 -.IX Item "-mips1" -Issue instructions from level 1 of the \s-1MIPS\s0 \s-1ISA\s0. This is the default. -\&\fBr3000\fR is the default \fIcpu-type\fR at this \s-1ISA\s0 level. -.Ip "\fB\-mips2\fR" 4 -.IX Item "-mips2" -Issue instructions from level 2 of the \s-1MIPS\s0 \s-1ISA\s0 (branch likely, square -root instructions). \fBr6000\fR is the default \fIcpu-type\fR at this -\&\s-1ISA\s0 level. -.Ip "\fB\-mips3\fR" 4 -.IX Item "-mips3" -Issue instructions from level 3 of the \s-1MIPS\s0 \s-1ISA\s0 (64\-bit instructions). -\&\fBr4000\fR is the default \fIcpu-type\fR at this \s-1ISA\s0 level. -.Ip "\fB\-mips4\fR" 4 -.IX Item "-mips4" -Issue instructions from level 4 of the \s-1MIPS\s0 \s-1ISA\s0 (conditional move, -prefetch, enhanced \s-1FPU\s0 instructions). \fBr8000\fR is the default -\&\fIcpu-type\fR at this \s-1ISA\s0 level. -.Ip "\fB\-mfp32\fR" 4 -.IX Item "-mfp32" -Assume that 32 32\-bit floating point registers are available. This is -the default. -.Ip "\fB\-mfp64\fR" 4 -.IX Item "-mfp64" -Assume that 32 64\-bit floating point registers are available. This is -the default when the \fB\-mips3\fR option is used. -.Ip "\fB\-mfused-madd\fR" 4 -.IX Item "-mfused-madd" -.PD 0 -.Ip "\fB\-mno-fused-madd\fR" 4 -.IX Item "-mno-fused-madd" -.PD -Generate code that uses (does not use) the floating point multiply and -accumulate instructions, when they are available. These instructions -are generated by default if they are available, but this may be -undesirable if the extra precision causes problems or on certain chips -in the mode where denormals are rounded to zero where denormals -generated by multiply and accumulate instructions cause exceptions -anyway. -.Ip "\fB\-mgp32\fR" 4 -.IX Item "-mgp32" -Assume that 32 32\-bit general purpose registers are available. This is -the default. -.Ip "\fB\-mgp64\fR" 4 -.IX Item "-mgp64" -Assume that 32 64\-bit general purpose registers are available. This is -the default when the \fB\-mips3\fR option is used. -.Ip "\fB\-mint64\fR" 4 -.IX Item "-mint64" -Force int and long types to be 64 bits wide. See \fB\-mlong32\fR for an -explanation of the default, and the width of pointers. -.Ip "\fB\-mlong64\fR" 4 -.IX Item "-mlong64" -Force long types to be 64 bits wide. See \fB\-mlong32\fR for an -explanation of the default, and the width of pointers. -.Ip "\fB\-mlong32\fR" 4 -.IX Item "-mlong32" -Force long, int, and pointer types to be 32 bits wide. -.Sp -If none of \fB\-mlong32\fR, \fB\-mlong64\fR, or \fB\-mint64\fR are set, -the size of ints, longs, and pointers depends on the \s-1ABI\s0 and \s-1ISA\s0 chosen. -For \fB\-mabi=32\fR, and \fB\-mabi=n32\fR, ints and longs are 32 bits -wide. For \fB\-mabi=64\fR, ints are 32 bits, and longs are 64 bits wide. -For \fB\-mabi=eabi\fR and either \fB\-mips1\fR or \fB\-mips2\fR, ints -and longs are 32 bits wide. For \fB\-mabi=eabi\fR and higher ISAs, ints -are 32 bits, and longs are 64 bits wide. The width of pointer types is -the smaller of the width of longs or the width of general purpose -registers (which in turn depends on the \s-1ISA\s0). -.Ip "\fB\-mabi=32\fR" 4 -.IX Item "-mabi=32" -.PD 0 -.Ip "\fB\-mabi=o64\fR" 4 -.IX Item "-mabi=o64" -.Ip "\fB\-mabi=n32\fR" 4 -.IX Item "-mabi=n32" -.Ip "\fB\-mabi=64\fR" 4 -.IX Item "-mabi=64" -.Ip "\fB\-mabi=eabi\fR" 4 -.IX Item "-mabi=eabi" -.PD -Generate code for the indicated \s-1ABI\s0. The default instruction level is -\&\fB\-mips1\fR for \fB32\fR, \fB\-mips3\fR for \fBn32\fR, and -\&\fB\-mips4\fR otherwise. Conversely, with \fB\-mips1\fR or -\&\fB\-mips2\fR, the default \s-1ABI\s0 is \fB32\fR; otherwise, the default \s-1ABI\s0 -is \fB64\fR. -.Ip "\fB\-mmips-as\fR" 4 -.IX Item "-mmips-as" -Generate code for the \s-1MIPS\s0 assembler, and invoke \fImips-tfile\fR to -add normal debug information. This is the default for all -platforms except for the \s-1OSF/1\s0 reference platform, using the OSF/rose -object format. If the either of the \fB\-gstabs\fR or \fB\-gstabs+\fR -switches are used, the \fImips-tfile\fR program will encapsulate the -stabs within \s-1MIPS\s0 \s-1ECOFF\s0. -.Ip "\fB\-mgas\fR" 4 -.IX Item "-mgas" -Generate code for the \s-1GNU\s0 assembler. This is the default on the \s-1OSF/1\s0 -reference platform, using the OSF/rose object format. Also, this is -the default if the configure option \fB\*(--with-gnu-as\fR is used. -.Ip "\fB\-msplit-addresses\fR" 4 -.IX Item "-msplit-addresses" -.PD 0 -.Ip "\fB\-mno-split-addresses\fR" 4 -.IX Item "-mno-split-addresses" -.PD -Generate code to load the high and low parts of address constants separately. -This allows \s-1GCC\s0 to optimize away redundant loads of the high order -bits of addresses. This optimization requires \s-1GNU\s0 as and \s-1GNU\s0 ld. -This optimization is enabled by default for some embedded targets where -\&\s-1GNU\s0 as and \s-1GNU\s0 ld are standard. -.Ip "\fB\-mrnames\fR" 4 -.IX Item "-mrnames" -.PD 0 -.Ip "\fB\-mno-rnames\fR" 4 -.IX Item "-mno-rnames" -.PD -The \fB\-mrnames\fR switch says to output code using the \s-1MIPS\s0 software -names for the registers, instead of the hardware names (ie, \fIa0\fR -instead of \fI$4\fR). The only known assembler that supports this option -is the Algorithmics assembler. -.Ip "\fB\-mgpopt\fR" 4 -.IX Item "-mgpopt" -.PD 0 -.Ip "\fB\-mno-gpopt\fR" 4 -.IX Item "-mno-gpopt" -.PD -The \fB\-mgpopt\fR switch says to write all of the data declarations -before the instructions in the text section, this allows the \s-1MIPS\s0 -assembler to generate one word memory references instead of using two -words for short global or static data items. This is on by default if -optimization is selected. -.Ip "\fB\-mstats\fR" 4 -.IX Item "-mstats" -.PD 0 -.Ip "\fB\-mno-stats\fR" 4 -.IX Item "-mno-stats" -.PD -For each non-inline function processed, the \fB\-mstats\fR switch -causes the compiler to emit one line to the standard error file to -print statistics about the program (number of registers saved, stack -size, etc.). -.Ip "\fB\-mmemcpy\fR" 4 -.IX Item "-mmemcpy" -.PD 0 -.Ip "\fB\-mno-memcpy\fR" 4 -.IX Item "-mno-memcpy" -.PD -The \fB\-mmemcpy\fR switch makes all block moves call the appropriate -string function (\fBmemcpy\fR or \fBbcopy\fR) instead of possibly -generating inline code. -.Ip "\fB\-mmips-tfile\fR" 4 -.IX Item "-mmips-tfile" -.PD 0 -.Ip "\fB\-mno-mips-tfile\fR" 4 -.IX Item "-mno-mips-tfile" -.PD -The \fB\-mno-mips-tfile\fR switch causes the compiler not -postprocess the object file with the \fImips-tfile\fR program, -after the \s-1MIPS\s0 assembler has generated it to add debug support. If -\&\fImips-tfile\fR is not run, then no local variables will be -available to the debugger. In addition, \fIstage2\fR and -\&\fIstage3\fR objects will have the temporary file names passed to the -assembler embedded in the object file, which means the objects will -not compare the same. The \fB\-mno-mips-tfile\fR switch should only -be used when there are bugs in the \fImips-tfile\fR program that -prevents compilation. -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -Generate output containing library calls for floating point. -\&\fBWarning:\fR the requisite libraries are not part of \s-1GCC\s0. -Normally the facilities of the machine's usual C compiler are used, but -this can't be done directly in cross-compilation. You must make your -own arrangements to provide suitable library functions for -cross-compilation. -.Ip "\fB\-mhard-float\fR" 4 -.IX Item "-mhard-float" -Generate output containing floating point instructions. This is the -default if you use the unmodified sources. -.Ip "\fB\-mabicalls\fR" 4 -.IX Item "-mabicalls" -.PD 0 -.Ip "\fB\-mno-abicalls\fR" 4 -.IX Item "-mno-abicalls" -.PD -Emit (or do not emit) the pseudo operations \fB.abicalls\fR, -\&\fB.cpload\fR, and \fB.cprestore\fR that some System V.4 ports use for -position independent code. -.Ip "\fB\-mlong-calls\fR" 4 -.IX Item "-mlong-calls" -.PD 0 -.Ip "\fB\-mno-long-calls\fR" 4 -.IX Item "-mno-long-calls" -.PD -Do all calls with the \fB\s-1JALR\s0\fR instruction, which requires -loading up a function's address into a register before the call. -You need to use this switch, if you call outside of the current -512 megabyte segment to functions that are not through pointers. -.Ip "\fB\-mhalf-pic\fR" 4 -.IX Item "-mhalf-pic" -.PD 0 -.Ip "\fB\-mno-half-pic\fR" 4 -.IX Item "-mno-half-pic" -.PD -Put pointers to extern references into the data section and load them -up, rather than put the references in the text section. -.Ip "\fB\-membedded-pic\fR" 4 -.IX Item "-membedded-pic" -.PD 0 -.Ip "\fB\-mno-embedded-pic\fR" 4 -.IX Item "-mno-embedded-pic" -.PD -Generate \s-1PIC\s0 code suitable for some embedded systems. All calls are -made using \s-1PC\s0 relative address, and all data is addressed using the \f(CW$gp\fR -register. No more than 65536 bytes of global data may be used. This -requires \s-1GNU\s0 as and \s-1GNU\s0 ld which do most of the work. This currently -only works on targets which use \s-1ECOFF\s0; it does not work with \s-1ELF\s0. -.Ip "\fB\-membedded-data\fR" 4 -.IX Item "-membedded-data" -.PD 0 -.Ip "\fB\-mno-embedded-data\fR" 4 -.IX Item "-mno-embedded-data" -.PD -Allocate variables to the read-only data section first if possible, then -next in the small data section if possible, otherwise in data. This gives -slightly slower code than the default, but reduces the amount of \s-1RAM\s0 required -when executing, and thus may be preferred for some embedded systems. -.Ip "\fB\-muninit-const-in-rodata\fR" 4 -.IX Item "-muninit-const-in-rodata" -.PD 0 -.Ip "\fB\-mno-uninit-const-in-rodata\fR" 4 -.IX Item "-mno-uninit-const-in-rodata" -.PD -When used together with \fB\-membedded-data\fR, it will always store uninitialized -const variables in the read-only data section. -.Ip "\fB\-msingle-float\fR" 4 -.IX Item "-msingle-float" -.PD 0 -.Ip "\fB\-mdouble-float\fR" 4 -.IX Item "-mdouble-float" -.PD -The \fB\-msingle-float\fR switch tells gcc to assume that the floating -point coprocessor only supports single precision operations, as on the -\&\fBr4650\fR chip. The \fB\-mdouble-float\fR switch permits gcc to use -double precision operations. This is the default. -.Ip "\fB\-mmad\fR" 4 -.IX Item "-mmad" -.PD 0 -.Ip "\fB\-mno-mad\fR" 4 -.IX Item "-mno-mad" -.PD -Permit use of the \fBmad\fR, \fBmadu\fR and \fBmul\fR instructions, -as on the \fBr4650\fR chip. -.Ip "\fB\-m4650\fR" 4 -.IX Item "-m4650" -Turns on \fB\-msingle-float\fR, \fB\-mmad\fR, and, at least for now, -\&\fB\-mcpu=r4650\fR. -.Ip "\fB\-mips16\fR" 4 -.IX Item "-mips16" -.PD 0 -.Ip "\fB\-mno-mips16\fR" 4 -.IX Item "-mno-mips16" -.PD -Enable 16\-bit instructions. -.Ip "\fB\-mentry\fR" 4 -.IX Item "-mentry" -Use the entry and exit pseudo ops. This option can only be used with -\&\fB\-mips16\fR. -.Ip "\fB\-EL\fR" 4 -.IX Item "-EL" -Compile code for the processor in little endian mode. -The requisite libraries are assumed to exist. -.Ip "\fB\-EB\fR" 4 -.IX Item "-EB" -Compile code for the processor in big endian mode. -The requisite libraries are assumed to exist. -.Ip "\fB\-G\fR \fInum\fR" 4 -.IX Item "-G num" -Put global and static items less than or equal to \fInum\fR bytes into -the small data or bss sections instead of the normal data or bss -section. This allows the assembler to emit one word memory reference -instructions based on the global pointer (\fIgp\fR or \fI$28\fR), -instead of the normal two words used. By default, \fInum\fR is 8 when -the \s-1MIPS\s0 assembler is used, and 0 when the \s-1GNU\s0 assembler is used. The -\&\fB\-G\fR \fInum\fR switch is also passed to the assembler and linker. -All modules should be compiled with the same \fB\-G\fR \fInum\fR -value. -.Ip "\fB\-nocpp\fR" 4 -.IX Item "-nocpp" -Tell the \s-1MIPS\s0 assembler to not run its preprocessor over user -assembler files (with a \fB.s\fR suffix) when assembling them. -.Ip "\fB\-mfix7000\fR" 4 -.IX Item "-mfix7000" -Pass an option to gas which will cause nops to be inserted if -the read of the destination register of an mfhi or mflo instruction -occurs in the following two instructions. -.Ip "\fB\-no-crt0\fR" 4 -.IX Item "-no-crt0" -Do not include the default crt0. -.Ip "\fB\-mflush-func=\fR\fIfunc\fR" 4 -.IX Item "-mflush-func=func" -.PD 0 -.Ip "\fB\-mno-flush-func\fR" 4 -.IX Item "-mno-flush-func" -.PD -Specifies the function to call to flush the I and D caches, or to not -call any such function. If called, the function must take the same -arguments as the common \f(CW\*(C`_flush_func()\*(C'\fR, that is, the address of the -memory range for which the cache is being flushed, the size of the -memory range, and the number 3 (to flush both caches). The default -depends on the target gcc was configured for, but commonly is either -\&\fB_flush_func\fR or \fB_\|_cpu_flush\fR. -.PP -These options are defined by the macro -\&\f(CW\*(C`TARGET_SWITCHES\*(C'\fR in the machine description. The default for the -options is also defined by that macro, which enables you to change the -defaults. -.PP -.I "Intel 386 and \s-1AMD\s0 x86\-64 Options" -.IX Subsection "Intel 386 and AMD x86-64 Options" -.PP -These \fB\-m\fR options are defined for the i386 and x86\-64 family of -computers: -.Ip "\fB\-mcpu=\fR\fIcpu-type\fR" 4 -.IX Item "-mcpu=cpu-type" -Tune to \fIcpu-type\fR everything applicable about the generated code, except -for the \s-1ABI\s0 and the set of available instructions. The choices for -\&\fIcpu-type\fR are \fBi386\fR, \fBi486\fR, \fBi586\fR, \fBi686\fR, -\&\fBpentium\fR, \fBpentium-mmx\fR, \fBpentiumpro\fR, \fBpentium2\fR, -\&\fBpentium3\fR, \fBpentium4\fR, \fBk6\fR, \fBk6\-2\fR, \fBk6\-3\fR, -\&\fBathlon\fR, \fBathlon-tbird\fR, \fBathlon-4\fR, \fBathlon-xp\fR -and \fBathlon-mp\fR. -.Sp -While picking a specific \fIcpu-type\fR will schedule things appropriately -for that particular chip, the compiler will not generate any code that -does not run on the i386 without the \fB\-march=\fR\fIcpu-type\fR option -being used. \fBi586\fR is equivalent to \fBpentium\fR and \fBi686\fR -is equivalent to \fBpentiumpro\fR. \fBk6\fR and \fBathlon\fR are the -\&\s-1AMD\s0 chips as opposed to the Intel ones. -.Ip "\fB\-march=\fR\fIcpu-type\fR" 4 -.IX Item "-march=cpu-type" -Generate instructions for the machine type \fIcpu-type\fR. The choices -for \fIcpu-type\fR are the same as for \fB\-mcpu\fR. Moreover, -specifying \fB\-march=\fR\fIcpu-type\fR implies \fB\-mcpu=\fR\fIcpu-type\fR. -.Ip "\fB\-m386\fR" 4 -.IX Item "-m386" -.PD 0 -.Ip "\fB\-m486\fR" 4 -.IX Item "-m486" -.Ip "\fB\-mpentium\fR" 4 -.IX Item "-mpentium" -.Ip "\fB\-mpentiumpro\fR" 4 -.IX Item "-mpentiumpro" -.PD -These options are synonyms for \fB\-mcpu=i386\fR, \fB\-mcpu=i486\fR, -\&\fB\-mcpu=pentium\fR, and \fB\-mcpu=pentiumpro\fR respectively. -These synonyms are deprecated. -.Ip "\fB\-mfpmath=\fR\fIunit\fR" 4 -.IX Item "-mfpmath=unit" -generate floating point arithmetics for selected unit \fIunit\fR. the choices -for \fIunit\fR are: -.RS 4 -.Ip "\fB387\fR" 4 -.IX Item "387" -Use the standard 387 floating point coprocessor present majority of chips and -emulated otherwise. Code compiled with this option will run almost everywhere. -The temporary results are computed in 80bit precesion instead of precision -specified by the type resulting in slightly different results compared to most -of other chips. See \fB\-ffloat-store\fR for more detailed description. -.Sp -This is the default choice for i386 compiler. -.Ip "\fBsse\fR" 4 -.IX Item "sse" -Use scalar floating point instructions present in the \s-1SSE\s0 instruction set. -This instruction set is supported by Pentium3 and newer chips, in the \s-1AMD\s0 line -by Athlon-4, Athlon-xp and Athlon-mp chips. The earlier version of \s-1SSE\s0 -instruction set supports only single precision arithmetics, thus the double and -extended precision arithmetics is still done using 387. Later version, present -only in Pentium4 and the future \s-1AMD\s0 x86\-64 chips supports double precision -arithmetics too. -.Sp -For i387 you need to use \fB\-march=\fR\fIcpu-type\fR, \fB\-msse\fR or -\&\fB\-msse2\fR switches to enable \s-1SSE\s0 extensions and make this option -effective. For x86\-64 compiler, these extensions are enabled by default. -.Sp -The resulting code should be considerably faster in majority of cases and avoid -the numerical instability problems of 387 code, but may break some existing -code that expects temporaries to be 80bit. -.Sp -This is the default choice for x86\-64 compiler. -.Ip "\fBsse,387\fR" 4 -.IX Item "sse,387" -Attempt to utilize both instruction sets at once. This effectivly double the -amount of available registers and on chips with separate execution units for -387 and \s-1SSE\s0 the execution resources too. Use this option with care, as it is -still experimental, because gcc register allocator does not model separate -functional units well resulting in instable performance. -.RE -.RS 4 -.RE -.Ip "\fB\-masm=\fR\fIdialect\fR" 4 -.IX Item "-masm=dialect" -Output asm instructions using selected \fIdialect\fR. Supported choices are -\&\fBintel\fR or \fBatt\fR (the default one). -.Ip "\fB\-mieee-fp\fR" 4 -.IX Item "-mieee-fp" -.PD 0 -.Ip "\fB\-mno-ieee-fp\fR" 4 -.IX Item "-mno-ieee-fp" -.PD -Control whether or not the compiler uses \s-1IEEE\s0 floating point -comparisons. These handle correctly the case where the result of a -comparison is unordered. -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -Generate output containing library calls for floating point. -\&\fBWarning:\fR the requisite libraries are not part of \s-1GCC\s0. -Normally the facilities of the machine's usual C compiler are used, but -this can't be done directly in cross-compilation. You must make your -own arrangements to provide suitable library functions for -cross-compilation. -.Sp -On machines where a function returns floating point results in the 80387 -register stack, some floating point opcodes may be emitted even if -\&\fB\-msoft-float\fR is used. -.Ip "\fB\-mno-fp-ret-in-387\fR" 4 -.IX Item "-mno-fp-ret-in-387" -Do not use the \s-1FPU\s0 registers for return values of functions. -.Sp -The usual calling convention has functions return values of types -\&\f(CW\*(C`float\*(C'\fR and \f(CW\*(C`double\*(C'\fR in an \s-1FPU\s0 register, even if there -is no \s-1FPU\s0. The idea is that the operating system should emulate -an \s-1FPU\s0. -.Sp -The option \fB\-mno-fp-ret-in-387\fR causes such values to be returned -in ordinary \s-1CPU\s0 registers instead. -.Ip "\fB\-mno-fancy-math-387\fR" 4 -.IX Item "-mno-fancy-math-387" -Some 387 emulators do not support the \f(CW\*(C`sin\*(C'\fR, \f(CW\*(C`cos\*(C'\fR and -\&\f(CW\*(C`sqrt\*(C'\fR instructions for the 387. Specify this option to avoid -generating those instructions. This option is the default on FreeBSD, -OpenBSD and NetBSD. This option is overridden when \fB\-march\fR -indicates that the target cpu will always have an \s-1FPU\s0 and so the -instruction will not need emulation. As of revision 2.6.1, these -instructions are not generated unless you also use the -\&\fB\-funsafe-math-optimizations\fR switch. -.Ip "\fB\-malign-double\fR" 4 -.IX Item "-malign-double" -.PD 0 -.Ip "\fB\-mno-align-double\fR" 4 -.IX Item "-mno-align-double" -.PD -Control whether \s-1GCC\s0 aligns \f(CW\*(C`double\*(C'\fR, \f(CW\*(C`long double\*(C'\fR, and -\&\f(CW\*(C`long long\*(C'\fR variables on a two word boundary or a one word -boundary. Aligning \f(CW\*(C`double\*(C'\fR variables on a two word boundary will -produce code that runs somewhat faster on a \fBPentium\fR at the -expense of more memory. -.Sp -\&\fBWarning:\fR if you use the \fB\-malign-double\fR switch, -structures containing the above types will be aligned differently than -the published application binary interface specifications for the 386 -and will not be binary compatible with structures in code compiled -without that switch. -.Ip "\fB\-m128bit-long-double\fR" 4 -.IX Item "-m128bit-long-double" -Control the size of \f(CW\*(C`long double\*(C'\fR type. i386 application binary interface -specify the size to be 12 bytes, while modern architectures (Pentium and newer) -prefer \f(CW\*(C`long double\*(C'\fR aligned to 8 or 16 byte boundary. This is -impossible to reach with 12 byte long doubles in the array accesses. -.Sp -\&\fBWarning:\fR if you use the \fB\-m128bit-long-double\fR switch, the -structures and arrays containing \f(CW\*(C`long double\*(C'\fR will change their size as -well as function calling convention for function taking \f(CW\*(C`long double\*(C'\fR -will be modified. -.Ip "\fB\-m96bit-long-double\fR" 4 -.IX Item "-m96bit-long-double" -Set the size of \f(CW\*(C`long double\*(C'\fR to 96 bits as required by the i386 -application binary interface. This is the default. -.Ip "\fB\-msvr3\-shlib\fR" 4 -.IX Item "-msvr3-shlib" -.PD 0 -.Ip "\fB\-mno-svr3\-shlib\fR" 4 -.IX Item "-mno-svr3-shlib" -.PD -Control whether \s-1GCC\s0 places uninitialized local variables into the -\&\f(CW\*(C`bss\*(C'\fR or \f(CW\*(C`data\*(C'\fR segments. \fB\-msvr3\-shlib\fR places them -into \f(CW\*(C`bss\*(C'\fR. These options are meaningful only on System V Release 3. -.Ip "\fB\-mrtd\fR" 4 -.IX Item "-mrtd" -Use a different function-calling convention, in which functions that -take a fixed number of arguments return with the \f(CW\*(C`ret\*(C'\fR \fInum\fR -instruction, which pops their arguments while returning. This saves one -instruction in the caller since there is no need to pop the arguments -there. -.Sp -You can specify that an individual function is called with this calling -sequence with the function attribute \fBstdcall\fR. You can also -override the \fB\-mrtd\fR option by using the function attribute -\&\fBcdecl\fR. -.Sp -\&\fBWarning:\fR this calling convention is incompatible with the one -normally used on Unix, so you cannot use it if you need to call -libraries compiled with the Unix compiler. -.Sp -Also, you must provide function prototypes for all functions that -take variable numbers of arguments (including \f(CW\*(C`printf\*(C'\fR); -otherwise incorrect code will be generated for calls to those -functions. -.Sp -In addition, seriously incorrect code will result if you call a -function with too many arguments. (Normally, extra arguments are -harmlessly ignored.) -.Ip "\fB\-mregparm=\fR\fInum\fR" 4 -.IX Item "-mregparm=num" -Control how many registers are used to pass integer arguments. By -default, no registers are used to pass arguments, and at most 3 -registers can be used. You can control this behavior for a specific -function by using the function attribute \fBregparm\fR. -.Sp -\&\fBWarning:\fR if you use this switch, and -\&\fInum\fR is nonzero, then you must build all modules with the same -value, including any libraries. This includes the system libraries and -startup modules. -.Ip "\fB\-mpreferred-stack-boundary=\fR\fInum\fR" 4 -.IX Item "-mpreferred-stack-boundary=num" -Attempt to keep the stack boundary aligned to a 2 raised to \fInum\fR -byte boundary. If \fB\-mpreferred-stack-boundary\fR is not specified, -the default is 4 (16 bytes or 128 bits), except when optimizing for code -size (\fB\-Os\fR), in which case the default is the minimum correct -alignment (4 bytes for x86, and 8 bytes for x86\-64). -.Sp -On Pentium and PentiumPro, \f(CW\*(C`double\*(C'\fR and \f(CW\*(C`long double\*(C'\fR values -should be aligned to an 8 byte boundary (see \fB\-malign-double\fR) or -suffer significant run time performance penalties. On Pentium \s-1III\s0, the -Streaming \s-1SIMD\s0 Extension (\s-1SSE\s0) data type \f(CW\*(C`_\|_m128\*(C'\fR suffers similar -penalties if it is not 16 byte aligned. -.Sp -To ensure proper alignment of this values on the stack, the stack boundary -must be as aligned as that required by any value stored on the stack. -Further, every function must be generated such that it keeps the stack -aligned. Thus calling a function compiled with a higher preferred -stack boundary from a function compiled with a lower preferred stack -boundary will most likely misalign the stack. It is recommended that -libraries that use callbacks always use the default setting. -.Sp -This extra alignment does consume extra stack space, and generally -increases code size. Code that is sensitive to stack space usage, such -as embedded systems and operating system kernels, may want to reduce the -preferred alignment to \fB\-mpreferred-stack-boundary=2\fR. -.Ip "\fB\-mmmx\fR" 4 -.IX Item "-mmmx" -.PD 0 -.Ip "\fB\-mno-mmx\fR" 4 -.IX Item "-mno-mmx" -.Ip "\fB\-msse\fR" 4 -.IX Item "-msse" -.Ip "\fB\-mno-sse\fR" 4 -.IX Item "-mno-sse" -.Ip "\fB\-msse2\fR" 4 -.IX Item "-msse2" -.Ip "\fB\-mno-sse2\fR" 4 -.IX Item "-mno-sse2" -.Ip "\fB\-m3dnow\fR" 4 -.IX Item "-m3dnow" -.Ip "\fB\-mno-3dnow\fR" 4 -.IX Item "-mno-3dnow" -.PD -These switches enable or disable the use of built-in functions that allow -direct access to the \s-1MMX\s0, \s-1SSE\s0 and 3Dnow extensions of the instruction set. -.Sp -To have \s-1SSE/SSE2\s0 instructions generated automatically from floating-point code, -see \fB\-mfpmath=sse\fR. -.Ip "\fB\-mpush-args\fR" 4 -.IX Item "-mpush-args" -.PD 0 -.Ip "\fB\-mno-push-args\fR" 4 -.IX Item "-mno-push-args" -.PD -Use \s-1PUSH\s0 operations to store outgoing parameters. This method is shorter -and usually equally fast as method using \s-1SUB/MOV\s0 operations and is enabled -by default. In some cases disabling it may improve performance because of -improved scheduling and reduced dependencies. -.Ip "\fB\-maccumulate-outgoing-args\fR" 4 -.IX Item "-maccumulate-outgoing-args" -If enabled, the maximum amount of space required for outgoing arguments will be -computed in the function prologue. This is faster on most modern CPUs -because of reduced dependencies, improved scheduling and reduced stack usage -when preferred stack boundary is not equal to 2. The drawback is a notable -increase in code size. This switch implies \fB\-mno-push-args\fR. -.Ip "\fB\-mthreads\fR" 4 -.IX Item "-mthreads" -Support thread-safe exception handling on \fBMingw32\fR. Code that relies -on thread-safe exception handling must compile and link all code with the -\&\fB\-mthreads\fR option. When compiling, \fB\-mthreads\fR defines -\&\fB\-D_MT\fR; when linking, it links in a special thread helper library -\&\fB\-lmingwthrd\fR which cleans up per thread exception handling data. -.Ip "\fB\-mno-align-stringops\fR" 4 -.IX Item "-mno-align-stringops" -Do not align destination of inlined string operations. This switch reduces -code size and improves performance in case the destination is already aligned, -but gcc don't know about it. -.Ip "\fB\-minline-all-stringops\fR" 4 -.IX Item "-minline-all-stringops" -By default \s-1GCC\s0 inlines string operations only when destination is known to be -aligned at least to 4 byte boundary. This enables more inlining, increase code -size, but may improve performance of code that depends on fast memcpy, strlen -and memset for short lengths. -.Ip "\fB\-momit-leaf-frame-pointer\fR" 4 -.IX Item "-momit-leaf-frame-pointer" -Don't keep the frame pointer in a register for leaf functions. This -avoids the instructions to save, set up and restore frame pointers and -makes an extra register available in leaf functions. The option -\&\fB\-fomit-frame-pointer\fR removes the frame pointer for all functions -which might make debugging harder. -.PP -These \fB\-m\fR switches are supported in addition to the above -on \s-1AMD\s0 x86\-64 processors in 64\-bit environments. -.Ip "\fB\-m32\fR" 4 -.IX Item "-m32" -.PD 0 -.Ip "\fB\-m64\fR" 4 -.IX Item "-m64" -.PD -Generate code for a 32\-bit or 64\-bit environment. -The 32\-bit environment sets int, long and pointer to 32 bits and -generates code that runs on any i386 system. -The 64\-bit environment sets int to 32 bits and long and pointer -to 64 bits and generates code for \s-1AMD\s0's x86\-64 architecture. -.Ip "\fB\-mno-red-zone\fR" 4 -.IX Item "-mno-red-zone" -Do not use a so called red zone for x86\-64 code. The red zone is mandated -by the x86\-64 \s-1ABI\s0, it is a 128\-byte area beyond the location of the -stack pointer that will not be modified by signal or interrupt handlers -and therefore can be used for temporary data without adjusting the stack -pointer. The flag \fB\-mno-red-zone\fR disables this red zone. -.Ip "\fB\-mcmodel=small\fR" 4 -.IX Item "-mcmodel=small" -Generate code for the small code model: the program and its symbols must -be linked in the lower 2 \s-1GB\s0 of the address space. Pointers are 64 bits. -Programs can be statically or dynamically linked. This is the default -code model. -.Ip "\fB\-mcmodel=kernel\fR" 4 -.IX Item "-mcmodel=kernel" -Generate code for the kernel code model. The kernel runs in the -negative 2 \s-1GB\s0 of the address space. -This model has to be used for Linux kernel code. -.Ip "\fB\-mcmodel=medium\fR" 4 -.IX Item "-mcmodel=medium" -Generate code for the medium model: The program is linked in the lower 2 -\&\s-1GB\s0 of the address space but symbols can be located anywhere in the -address space. Programs can be statically or dynamically linked, but -building of shared libraries are not supported with the medium model. -.Ip "\fB\-mcmodel=large\fR" 4 -.IX Item "-mcmodel=large" -Generate code for the large model: This model makes no assumptions -about addresses and sizes of sections. Currently \s-1GCC\s0 does not implement -this model. -.PP -.I "\s-1HPPA\s0 Options" -.IX Subsection "HPPA Options" -.PP -These \fB\-m\fR options are defined for the \s-1HPPA\s0 family of computers: -.Ip "\fB\-march=\fR\fIarchitecture-type\fR" 4 -.IX Item "-march=architecture-type" -Generate code for the specified architecture. The choices for -\&\fIarchitecture-type\fR are \fB1.0\fR for \s-1PA\s0 1.0, \fB1.1\fR for \s-1PA\s0 -1.1, and \fB2.0\fR for \s-1PA\s0 2.0 processors. Refer to -\&\fI/usr/lib/sched.models\fR on an \s-1HP-UX\s0 system to determine the proper -architecture option for your machine. Code compiled for lower numbered -architectures will run on higher numbered architectures, but not the -other way around. -.Sp -\&\s-1PA\s0 2.0 support currently requires gas snapshot 19990413 or later. The -next release of binutils (current is 2.9.1) will probably contain \s-1PA\s0 2.0 -support. -.Ip "\fB\-mpa-risc-1\-0\fR" 4 -.IX Item "-mpa-risc-1-0" -.PD 0 -.Ip "\fB\-mpa-risc-1\-1\fR" 4 -.IX Item "-mpa-risc-1-1" -.Ip "\fB\-mpa-risc-2\-0\fR" 4 -.IX Item "-mpa-risc-2-0" -.PD -Synonyms for \fB\-march=1.0\fR, \fB\-march=1.1\fR, and \fB\-march=2.0\fR respectively. -.Ip "\fB\-mbig-switch\fR" 4 -.IX Item "-mbig-switch" -Generate code suitable for big switch tables. Use this option only if -the assembler/linker complain about out of range branches within a switch -table. -.Ip "\fB\-mjump-in-delay\fR" 4 -.IX Item "-mjump-in-delay" -Fill delay slots of function calls with unconditional jump instructions -by modifying the return pointer for the function call to be the target -of the conditional jump. -.Ip "\fB\-mdisable-fpregs\fR" 4 -.IX Item "-mdisable-fpregs" -Prevent floating point registers from being used in any manner. This is -necessary for compiling kernels which perform lazy context switching of -floating point registers. If you use this option and attempt to perform -floating point operations, the compiler will abort. -.Ip "\fB\-mdisable-indexing\fR" 4 -.IX Item "-mdisable-indexing" -Prevent the compiler from using indexing address modes. This avoids some -rather obscure problems when compiling \s-1MIG\s0 generated code under \s-1MACH\s0. -.Ip "\fB\-mno-space-regs\fR" 4 -.IX Item "-mno-space-regs" -Generate code that assumes the target has no space registers. This allows -\&\s-1GCC\s0 to generate faster indirect calls and use unscaled index address modes. -.Sp -Such code is suitable for level 0 \s-1PA\s0 systems and kernels. -.Ip "\fB\-mfast-indirect-calls\fR" 4 -.IX Item "-mfast-indirect-calls" -Generate code that assumes calls never cross space boundaries. This -allows \s-1GCC\s0 to emit code which performs faster indirect calls. -.Sp -This option will not work in the presence of shared libraries or nested -functions. -.Ip "\fB\-mlong-load-store\fR" 4 -.IX Item "-mlong-load-store" -Generate 3\-instruction load and store sequences as sometimes required by -the \s-1HP-UX\s0 10 linker. This is equivalent to the \fB+k\fR option to -the \s-1HP\s0 compilers. -.Ip "\fB\-mportable-runtime\fR" 4 -.IX Item "-mportable-runtime" -Use the portable calling conventions proposed by \s-1HP\s0 for \s-1ELF\s0 systems. -.Ip "\fB\-mgas\fR" 4 -.IX Item "-mgas" -Enable the use of assembler directives only \s-1GAS\s0 understands. -.Ip "\fB\-mschedule=\fR\fIcpu-type\fR" 4 -.IX Item "-mschedule=cpu-type" -Schedule code according to the constraints for the machine type -\&\fIcpu-type\fR. The choices for \fIcpu-type\fR are \fB700\fR -\&\fB7100\fR, \fB7100LC\fR, \fB7200\fR, and \fB8000\fR. Refer to -\&\fI/usr/lib/sched.models\fR on an \s-1HP-UX\s0 system to determine the -proper scheduling option for your machine. -.Ip "\fB\-mlinker-opt\fR" 4 -.IX Item "-mlinker-opt" -Enable the optimization pass in the \s-1HPUX\s0 linker. Note this makes symbolic -debugging impossible. It also triggers a bug in the \s-1HPUX\s0 8 and \s-1HPUX\s0 9 linkers -in which they give bogus error messages when linking some programs. -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -Generate output containing library calls for floating point. -\&\fBWarning:\fR the requisite libraries are not available for all \s-1HPPA\s0 -targets. Normally the facilities of the machine's usual C compiler are -used, but this cannot be done directly in cross-compilation. You must make -your own arrangements to provide suitable library functions for -cross-compilation. The embedded target \fBhppa1.1\-*\-pro\fR -does provide software floating point support. -.Sp -\&\fB\-msoft-float\fR changes the calling convention in the output file; -therefore, it is only useful if you compile \fIall\fR of a program with -this option. In particular, you need to compile \fIlibgcc.a\fR, the -library that comes with \s-1GCC\s0, with \fB\-msoft-float\fR in order for -this to work. -.PP -.I "Intel 960 Options" -.IX Subsection "Intel 960 Options" -.PP -These \fB\-m\fR options are defined for the Intel 960 implementations: -.Ip "\fB\-m\fR\fIcpu-type\fR" 4 -.IX Item "-mcpu-type" -Assume the defaults for the machine type \fIcpu-type\fR for some of -the other options, including instruction scheduling, floating point -support, and addressing modes. The choices for \fIcpu-type\fR are -\&\fBka\fR, \fBkb\fR, \fBmc\fR, \fBca\fR, \fBcf\fR, -\&\fBsa\fR, and \fBsb\fR. -The default is -\&\fBkb\fR. -.Ip "\fB\-mnumerics\fR" 4 -.IX Item "-mnumerics" -.PD 0 -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -.PD -The \fB\-mnumerics\fR option indicates that the processor does support -floating-point instructions. The \fB\-msoft-float\fR option indicates -that floating-point support should not be assumed. -.Ip "\fB\-mleaf-procedures\fR" 4 -.IX Item "-mleaf-procedures" -.PD 0 -.Ip "\fB\-mno-leaf-procedures\fR" 4 -.IX Item "-mno-leaf-procedures" -.PD -Do (or do not) attempt to alter leaf procedures to be callable with the -\&\f(CW\*(C`bal\*(C'\fR instruction as well as \f(CW\*(C`call\*(C'\fR. This will result in more -efficient code for explicit calls when the \f(CW\*(C`bal\*(C'\fR instruction can be -substituted by the assembler or linker, but less efficient code in other -cases, such as calls via function pointers, or using a linker that doesn't -support this optimization. -.Ip "\fB\-mtail-call\fR" 4 -.IX Item "-mtail-call" -.PD 0 -.Ip "\fB\-mno-tail-call\fR" 4 -.IX Item "-mno-tail-call" -.PD -Do (or do not) make additional attempts (beyond those of the -machine-independent portions of the compiler) to optimize tail-recursive -calls into branches. You may not want to do this because the detection of -cases where this is not valid is not totally complete. The default is -\&\fB\-mno-tail-call\fR. -.Ip "\fB\-mcomplex-addr\fR" 4 -.IX Item "-mcomplex-addr" -.PD 0 -.Ip "\fB\-mno-complex-addr\fR" 4 -.IX Item "-mno-complex-addr" -.PD -Assume (or do not assume) that the use of a complex addressing mode is a -win on this implementation of the i960. Complex addressing modes may not -be worthwhile on the K-series, but they definitely are on the C-series. -The default is currently \fB\-mcomplex-addr\fR for all processors except -the \s-1CB\s0 and \s-1CC\s0. -.Ip "\fB\-mcode-align\fR" 4 -.IX Item "-mcode-align" -.PD 0 -.Ip "\fB\-mno-code-align\fR" 4 -.IX Item "-mno-code-align" -.PD -Align code to 8\-byte boundaries for faster fetching (or don't bother). -Currently turned on by default for C-series implementations only. -.Ip "\fB\-mic-compat\fR" 4 -.IX Item "-mic-compat" -.PD 0 -.Ip "\fB\-mic2.0\-compat\fR" 4 -.IX Item "-mic2.0-compat" -.Ip "\fB\-mic3.0\-compat\fR" 4 -.IX Item "-mic3.0-compat" -.PD -Enable compatibility with iC960 v2.0 or v3.0. -.Ip "\fB\-masm-compat\fR" 4 -.IX Item "-masm-compat" -.PD 0 -.Ip "\fB\-mintel-asm\fR" 4 -.IX Item "-mintel-asm" -.PD -Enable compatibility with the iC960 assembler. -.Ip "\fB\-mstrict-align\fR" 4 -.IX Item "-mstrict-align" -.PD 0 -.Ip "\fB\-mno-strict-align\fR" 4 -.IX Item "-mno-strict-align" -.PD -Do not permit (do permit) unaligned accesses. -.Ip "\fB\-mold-align\fR" 4 -.IX Item "-mold-align" -Enable structure-alignment compatibility with Intel's gcc release version -1.3 (based on gcc 1.37). This option implies \fB\-mstrict-align\fR. -.Ip "\fB\-mlong-double-64\fR" 4 -.IX Item "-mlong-double-64" -Implement type \fBlong double\fR as 64\-bit floating point numbers. -Without the option \fBlong double\fR is implemented by 80\-bit -floating point numbers. The only reason we have it because there is -no 128\-bit \fBlong double\fR support in \fBfp-bit.c\fR yet. So it -is only useful for people using soft-float targets. Otherwise, we -should recommend against use of it. -.PP -.I "\s-1DEC\s0 Alpha Options" -.IX Subsection "DEC Alpha Options" -.PP -These \fB\-m\fR options are defined for the \s-1DEC\s0 Alpha implementations: -.Ip "\fB\-mno-soft-float\fR" 4 -.IX Item "-mno-soft-float" -.PD 0 -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -.PD -Use (do not use) the hardware floating-point instructions for -floating-point operations. When \fB\-msoft-float\fR is specified, -functions in \fIlibgcc.a\fR will be used to perform floating-point -operations. Unless they are replaced by routines that emulate the -floating-point operations, or compiled in such a way as to call such -emulations routines, these routines will issue floating-point -operations. If you are compiling for an Alpha without floating-point -operations, you must ensure that the library is built so as not to call -them. -.Sp -Note that Alpha implementations without floating-point operations are -required to have floating-point registers. -.Ip "\fB\-mfp-reg\fR" 4 -.IX Item "-mfp-reg" -.PD 0 -.Ip "\fB\-mno-fp-regs\fR" 4 -.IX Item "-mno-fp-regs" -.PD -Generate code that uses (does not use) the floating-point register set. -\&\fB\-mno-fp-regs\fR implies \fB\-msoft-float\fR. If the floating-point -register set is not used, floating point operands are passed in integer -registers as if they were integers and floating-point results are passed -in \f(CW\*(C`$0\*(C'\fR instead of \f(CW\*(C`$f0\*(C'\fR. This is a non-standard calling sequence, -so any function with a floating-point argument or return value called by code -compiled with \fB\-mno-fp-regs\fR must also be compiled with that -option. -.Sp -A typical use of this option is building a kernel that does not use, -and hence need not save and restore, any floating-point registers. -.Ip "\fB\-mieee\fR" 4 -.IX Item "-mieee" -The Alpha architecture implements floating-point hardware optimized for -maximum performance. It is mostly compliant with the \s-1IEEE\s0 floating -point standard. However, for full compliance, software assistance is -required. This option generates code fully \s-1IEEE\s0 compliant code -\&\fIexcept\fR that the \fIinexact-flag\fR is not maintained (see below). -If this option is turned on, the preprocessor macro \f(CW\*(C`_IEEE_FP\*(C'\fR is -defined during compilation. The resulting code is less efficient but is -able to correctly support denormalized numbers and exceptional \s-1IEEE\s0 -values such as not-a-number and plus/minus infinity. Other Alpha -compilers call this option \fB\-ieee_with_no_inexact\fR. -.Ip "\fB\-mieee-with-inexact\fR" 4 -.IX Item "-mieee-with-inexact" -This is like \fB\-mieee\fR except the generated code also maintains -the \s-1IEEE\s0 \fIinexact-flag\fR. Turning on this option causes the -generated code to implement fully-compliant \s-1IEEE\s0 math. In addition to -\&\f(CW\*(C`_IEEE_FP\*(C'\fR, \f(CW\*(C`_IEEE_FP_EXACT\*(C'\fR is defined as a preprocessor -macro. On some Alpha implementations the resulting code may execute -significantly slower than the code generated by default. Since there is -very little code that depends on the \fIinexact-flag\fR, you should -normally not specify this option. Other Alpha compilers call this -option \fB\-ieee_with_inexact\fR. -.Ip "\fB\-mfp-trap-mode=\fR\fItrap-mode\fR" 4 -.IX Item "-mfp-trap-mode=trap-mode" -This option controls what floating-point related traps are enabled. -Other Alpha compilers call this option \fB\-fptm\fR \fItrap-mode\fR. -The trap mode can be set to one of four values: -.RS 4 -.Ip "\fBn\fR" 4 -.IX Item "n" -This is the default (normal) setting. The only traps that are enabled -are the ones that cannot be disabled in software (e.g., division by zero -trap). -.Ip "\fBu\fR" 4 -.IX Item "u" -In addition to the traps enabled by \fBn\fR, underflow traps are enabled -as well. -.Ip "\fBsu\fR" 4 -.IX Item "su" -Like \fBsu\fR, but the instructions are marked to be safe for software -completion (see Alpha architecture manual for details). -.Ip "\fBsui\fR" 4 -.IX Item "sui" -Like \fBsu\fR, but inexact traps are enabled as well. -.RE -.RS 4 -.RE -.Ip "\fB\-mfp-rounding-mode=\fR\fIrounding-mode\fR" 4 -.IX Item "-mfp-rounding-mode=rounding-mode" -Selects the \s-1IEEE\s0 rounding mode. Other Alpha compilers call this option -\&\fB\-fprm\fR \fIrounding-mode\fR. The \fIrounding-mode\fR can be one -of: -.RS 4 -.Ip "\fBn\fR" 4 -.IX Item "n" -Normal \s-1IEEE\s0 rounding mode. Floating point numbers are rounded towards -the nearest machine number or towards the even machine number in case -of a tie. -.Ip "\fBm\fR" 4 -.IX Item "m" -Round towards minus infinity. -.Ip "\fBc\fR" 4 -.IX Item "c" -Chopped rounding mode. Floating point numbers are rounded towards zero. -.Ip "\fBd\fR" 4 -.IX Item "d" -Dynamic rounding mode. A field in the floating point control register -(\fIfpcr\fR, see Alpha architecture reference manual) controls the -rounding mode in effect. The C library initializes this register for -rounding towards plus infinity. Thus, unless your program modifies the -\&\fIfpcr\fR, \fBd\fR corresponds to round towards plus infinity. -.RE -.RS 4 -.RE -.Ip "\fB\-mtrap-precision=\fR\fItrap-precision\fR" 4 -.IX Item "-mtrap-precision=trap-precision" -In the Alpha architecture, floating point traps are imprecise. This -means without software assistance it is impossible to recover from a -floating trap and program execution normally needs to be terminated. -\&\s-1GCC\s0 can generate code that can assist operating system trap handlers -in determining the exact location that caused a floating point trap. -Depending on the requirements of an application, different levels of -precisions can be selected: -.RS 4 -.Ip "\fBp\fR" 4 -.IX Item "p" -Program precision. This option is the default and means a trap handler -can only identify which program caused a floating point exception. -.Ip "\fBf\fR" 4 -.IX Item "f" -Function precision. The trap handler can determine the function that -caused a floating point exception. -.Ip "\fBi\fR" 4 -.IX Item "i" -Instruction precision. The trap handler can determine the exact -instruction that caused a floating point exception. -.RE -.RS 4 -.Sp -Other Alpha compilers provide the equivalent options called -\&\fB\-scope_safe\fR and \fB\-resumption_safe\fR. -.RE -.Ip "\fB\-mieee-conformant\fR" 4 -.IX Item "-mieee-conformant" -This option marks the generated code as \s-1IEEE\s0 conformant. You must not -use this option unless you also specify \fB\-mtrap-precision=i\fR and either -\&\fB\-mfp-trap-mode=su\fR or \fB\-mfp-trap-mode=sui\fR. Its only effect -is to emit the line \fB.eflag 48\fR in the function prologue of the -generated assembly file. Under \s-1DEC\s0 Unix, this has the effect that -IEEE-conformant math library routines will be linked in. -.Ip "\fB\-mbuild-constants\fR" 4 -.IX Item "-mbuild-constants" -Normally \s-1GCC\s0 examines a 32\- or 64\-bit integer constant to -see if it can construct it from smaller constants in two or three -instructions. If it cannot, it will output the constant as a literal and -generate code to load it from the data segment at runtime. -.Sp -Use this option to require \s-1GCC\s0 to construct \fIall\fR integer constants -using code, even if it takes more instructions (the maximum is six). -.Sp -You would typically use this option to build a shared library dynamic -loader. Itself a shared library, it must relocate itself in memory -before it can find the variables and constants in its own data segment. -.Ip "\fB\-malpha-as\fR" 4 -.IX Item "-malpha-as" -.PD 0 -.Ip "\fB\-mgas\fR" 4 -.IX Item "-mgas" -.PD -Select whether to generate code to be assembled by the vendor-supplied -assembler (\fB\-malpha-as\fR) or by the \s-1GNU\s0 assembler \fB\-mgas\fR. -.Ip "\fB\-mbwx\fR" 4 -.IX Item "-mbwx" -.PD 0 -.Ip "\fB\-mno-bwx\fR" 4 -.IX Item "-mno-bwx" -.Ip "\fB\-mcix\fR" 4 -.IX Item "-mcix" -.Ip "\fB\-mno-cix\fR" 4 -.IX Item "-mno-cix" -.Ip "\fB\-mfix\fR" 4 -.IX Item "-mfix" -.Ip "\fB\-mno-fix\fR" 4 -.IX Item "-mno-fix" -.Ip "\fB\-mmax\fR" 4 -.IX Item "-mmax" -.Ip "\fB\-mno-max\fR" 4 -.IX Item "-mno-max" -.PD -Indicate whether \s-1GCC\s0 should generate code to use the optional \s-1BWX\s0, -\&\s-1CIX\s0, \s-1FIX\s0 and \s-1MAX\s0 instruction sets. The default is to use the instruction -sets supported by the \s-1CPU\s0 type specified via \fB\-mcpu=\fR option or that -of the \s-1CPU\s0 on which \s-1GCC\s0 was built if none was specified. -.Ip "\fB\-mfloat-vax\fR" 4 -.IX Item "-mfloat-vax" -.PD 0 -.Ip "\fB\-mfloat-ieee\fR" 4 -.IX Item "-mfloat-ieee" -.PD -Generate code that uses (does not use) \s-1VAX\s0 F and G floating point -arithmetic instead of \s-1IEEE\s0 single and double precision. -.Ip "\fB\-mexplicit-relocs\fR" 4 -.IX Item "-mexplicit-relocs" -.PD 0 -.Ip "\fB\-mno-explicit-relocs\fR" 4 -.IX Item "-mno-explicit-relocs" -.PD -Older Alpha assemblers provided no way to generate symbol relocations -except via assembler macros. Use of these macros does not allow -optimial instruction scheduling. \s-1GNU\s0 binutils as of version 2.12 -supports a new syntax that allows the compiler to explicitly mark -which relocations should apply to which instructions. This option -is mostly useful for debugging, as \s-1GCC\s0 detects the capabilities of -the assembler when it is built and sets the default accordingly. -.Ip "\fB\-msmall-data\fR" 4 -.IX Item "-msmall-data" -.PD 0 -.Ip "\fB\-mlarge-data\fR" 4 -.IX Item "-mlarge-data" -.PD -When \fB\-mexplicit-relocs\fR is in effect, static data is -accessed via \fIgp-relative\fR relocations. When \fB\-msmall-data\fR -is used, objects 8 bytes long or smaller are placed in a \fIsmall data area\fR -(the \f(CW\*(C`.sdata\*(C'\fR and \f(CW\*(C`.sbss\*(C'\fR sections) and are accessed via -16\-bit relocations off of the \f(CW\*(C`$gp\*(C'\fR register. This limits the -size of the small data area to 64KB, but allows the variables to be -directly accessed via a single instruction. -.Sp -The default is \fB\-mlarge-data\fR. With this option the data area -is limited to just below 2GB. Programs that require more than 2GB of -data must use \f(CW\*(C`malloc\*(C'\fR or \f(CW\*(C`mmap\*(C'\fR to allocate the data in the -heap instead of in the program's data segment. -.Sp -When generating code for shared libraries, \fB\-fpic\fR implies -\&\fB\-msmall-data\fR and \fB\-fPIC\fR implies \fB\-mlarge-data\fR. -.Ip "\fB\-mcpu=\fR\fIcpu_type\fR" 4 -.IX Item "-mcpu=cpu_type" -Set the instruction set and instruction scheduling parameters for -machine type \fIcpu_type\fR. You can specify either the \fB\s-1EV\s0\fR -style name or the corresponding chip number. \s-1GCC\s0 supports scheduling -parameters for the \s-1EV4\s0, \s-1EV5\s0 and \s-1EV6\s0 family of processors and will -choose the default values for the instruction set from the processor -you specify. If you do not specify a processor type, \s-1GCC\s0 will default -to the processor on which the compiler was built. -.Sp -Supported values for \fIcpu_type\fR are -.RS 4 -.Ip "\fBev4\fR" 4 -.IX Item "ev4" -.PD 0 -.Ip "\fBev45\fR" 4 -.IX Item "ev45" -.Ip "\fB21064\fR" 4 -.IX Item "21064" -.PD -Schedules as an \s-1EV4\s0 and has no instruction set extensions. -.Ip "\fBev5\fR" 4 -.IX Item "ev5" -.PD 0 -.Ip "\fB21164\fR" 4 -.IX Item "21164" -.PD -Schedules as an \s-1EV5\s0 and has no instruction set extensions. -.Ip "\fBev56\fR" 4 -.IX Item "ev56" -.PD 0 -.Ip "\fB21164a\fR" 4 -.IX Item "21164a" -.PD -Schedules as an \s-1EV5\s0 and supports the \s-1BWX\s0 extension. -.Ip "\fBpca56\fR" 4 -.IX Item "pca56" -.PD 0 -.Ip "\fB21164pc\fR" 4 -.IX Item "21164pc" -.Ip "\fB21164PC\fR" 4 -.IX Item "21164PC" -.PD -Schedules as an \s-1EV5\s0 and supports the \s-1BWX\s0 and \s-1MAX\s0 extensions. -.Ip "\fBev6\fR" 4 -.IX Item "ev6" -.PD 0 -.Ip "\fB21264\fR" 4 -.IX Item "21264" -.PD -Schedules as an \s-1EV6\s0 and supports the \s-1BWX\s0, \s-1FIX\s0, and \s-1MAX\s0 extensions. -.Ip "\fBev67\fR" 4 -.IX Item "ev67" -.PD 0 -.Ip "\fB21264a\fR" 4 -.IX Item "21264a" -.PD -Schedules as an \s-1EV6\s0 and supports the \s-1BWX\s0, \s-1CIX\s0, \s-1FIX\s0, and \s-1MAX\s0 extensions. -.RE -.RS 4 -.RE -.Ip "\fB\-mtune=\fR\fIcpu_type\fR" 4 -.IX Item "-mtune=cpu_type" -Set only the instruction scheduling parameters for machine type -\&\fIcpu_type\fR. The instruction set is not changed. -.Ip "\fB\-mmemory-latency=\fR\fItime\fR" 4 -.IX Item "-mmemory-latency=time" -Sets the latency the scheduler should assume for typical memory -references as seen by the application. This number is highly -dependent on the memory access patterns used by the application -and the size of the external cache on the machine. -.Sp -Valid options for \fItime\fR are -.RS 4 -.Ip "\fInumber\fR" 4 -.IX Item "number" -A decimal number representing clock cycles. -.Ip "\fBL1\fR" 4 -.IX Item "L1" -.PD 0 -.Ip "\fBL2\fR" 4 -.IX Item "L2" -.Ip "\fBL3\fR" 4 -.IX Item "L3" -.Ip "\fBmain\fR" 4 -.IX Item "main" -.PD -The compiler contains estimates of the number of clock cycles for -``typical'' \s-1EV4\s0 & \s-1EV5\s0 hardware for the Level 1, 2 & 3 caches -(also called Dcache, Scache, and Bcache), as well as to main memory. -Note that L3 is only valid for \s-1EV5\s0. -.RE -.RS 4 -.RE -.PP -.I "\s-1DEC\s0 Alpha/VMS Options" -.IX Subsection "DEC Alpha/VMS Options" -.PP -These \fB\-m\fR options are defined for the \s-1DEC\s0 Alpha/VMS implementations: -.Ip "\fB\-mvms-return-codes\fR" 4 -.IX Item "-mvms-return-codes" -Return \s-1VMS\s0 condition codes from main. The default is to return \s-1POSIX\s0 -style condition (e.g. error) codes. -.PP -.I "Clipper Options" -.IX Subsection "Clipper Options" -.PP -These \fB\-m\fR options are defined for the Clipper implementations: -.Ip "\fB\-mc300\fR" 4 -.IX Item "-mc300" -Produce code for a C300 Clipper processor. This is the default. -.Ip "\fB\-mc400\fR" 4 -.IX Item "-mc400" -Produce code for a C400 Clipper processor, i.e. use floating point -registers f8\*(--f15. -.PP -.I "H8/300 Options" -.IX Subsection "H8/300 Options" -.PP -These \fB\-m\fR options are defined for the H8/300 implementations: -.Ip "\fB\-mrelax\fR" 4 -.IX Item "-mrelax" -Shorten some address references at link time, when possible; uses the -linker option \fB\-relax\fR. -.Ip "\fB\-mh\fR" 4 -.IX Item "-mh" -Generate code for the H8/300H. -.Ip "\fB\-ms\fR" 4 -.IX Item "-ms" -Generate code for the H8/S. -.Ip "\fB\-ms2600\fR" 4 -.IX Item "-ms2600" -Generate code for the H8/S2600. This switch must be used with \fB\-ms\fR. -.Ip "\fB\-mint32\fR" 4 -.IX Item "-mint32" -Make \f(CW\*(C`int\*(C'\fR data 32 bits by default. -.Ip "\fB\-malign-300\fR" 4 -.IX Item "-malign-300" -On the H8/300H and H8/S, use the same alignment rules as for the H8/300. -The default for the H8/300H and H8/S is to align longs and floats on 4 -byte boundaries. -\&\fB\-malign-300\fR causes them to be aligned on 2 byte boundaries. -This option has no effect on the H8/300. -.PP -.I "\s-1SH\s0 Options" -.IX Subsection "SH Options" -.PP -These \fB\-m\fR options are defined for the \s-1SH\s0 implementations: -.Ip "\fB\-m1\fR" 4 -.IX Item "-m1" -Generate code for the \s-1SH1\s0. -.Ip "\fB\-m2\fR" 4 -.IX Item "-m2" -Generate code for the \s-1SH2\s0. -.Ip "\fB\-m3\fR" 4 -.IX Item "-m3" -Generate code for the \s-1SH3\s0. -.Ip "\fB\-m3e\fR" 4 -.IX Item "-m3e" -Generate code for the SH3e. -.Ip "\fB\-m4\-nofpu\fR" 4 -.IX Item "-m4-nofpu" -Generate code for the \s-1SH4\s0 without a floating-point unit. -.Ip "\fB\-m4\-single-only\fR" 4 -.IX Item "-m4-single-only" -Generate code for the \s-1SH4\s0 with a floating-point unit that only -supports single-precision arithmetic. -.Ip "\fB\-m4\-single\fR" 4 -.IX Item "-m4-single" -Generate code for the \s-1SH4\s0 assuming the floating-point unit is in -single-precision mode by default. -.Ip "\fB\-m4\fR" 4 -.IX Item "-m4" -Generate code for the \s-1SH4\s0. -.Ip "\fB\-mb\fR" 4 -.IX Item "-mb" -Compile code for the processor in big endian mode. -.Ip "\fB\-ml\fR" 4 -.IX Item "-ml" -Compile code for the processor in little endian mode. -.Ip "\fB\-mdalign\fR" 4 -.IX Item "-mdalign" -Align doubles at 64\-bit boundaries. Note that this changes the calling -conventions, and thus some functions from the standard C library will -not work unless you recompile it first with \fB\-mdalign\fR. -.Ip "\fB\-mrelax\fR" 4 -.IX Item "-mrelax" -Shorten some address references at link time, when possible; uses the -linker option \fB\-relax\fR. -.Ip "\fB\-mbigtable\fR" 4 -.IX Item "-mbigtable" -Use 32\-bit offsets in \f(CW\*(C`switch\*(C'\fR tables. The default is to use -16\-bit offsets. -.Ip "\fB\-mfmovd\fR" 4 -.IX Item "-mfmovd" -Enable the use of the instruction \f(CW\*(C`fmovd\*(C'\fR. -.Ip "\fB\-mhitachi\fR" 4 -.IX Item "-mhitachi" -Comply with the calling conventions defined by Hitachi. -.Ip "\fB\-mnomacsave\fR" 4 -.IX Item "-mnomacsave" -Mark the \f(CW\*(C`MAC\*(C'\fR register as call-clobbered, even if -\&\fB\-mhitachi\fR is given. -.Ip "\fB\-mieee\fR" 4 -.IX Item "-mieee" -Increase IEEE-compliance of floating-point code. -.Ip "\fB\-misize\fR" 4 -.IX Item "-misize" -Dump instruction size and location in the assembly code. -.Ip "\fB\-mpadstruct\fR" 4 -.IX Item "-mpadstruct" -This option is deprecated. It pads structures to multiple of 4 bytes, -which is incompatible with the \s-1SH\s0 \s-1ABI\s0. -.Ip "\fB\-mspace\fR" 4 -.IX Item "-mspace" -Optimize for space instead of speed. Implied by \fB\-Os\fR. -.Ip "\fB\-mprefergot\fR" 4 -.IX Item "-mprefergot" -When generating position-independent code, emit function calls using -the Global Offset Table instead of the Procedure Linkage Table. -.Ip "\fB\-musermode\fR" 4 -.IX Item "-musermode" -Generate a library function call to invalidate instruction cache -entries, after fixing up a trampoline. This library function call -doesn't assume it can write to the whole memory address space. This -is the default when the target is \f(CW\*(C`sh\-*\-linux*\*(C'\fR. -.PP -.I "Options for System V" -.IX Subsection "Options for System V" -.PP -These additional options are available on System V Release 4 for -compatibility with other compilers on those systems: -.Ip "\fB\-G\fR" 4 -.IX Item "-G" -Create a shared object. -It is recommended that \fB\-symbolic\fR or \fB\-shared\fR be used instead. -.Ip "\fB\-Qy\fR" 4 -.IX Item "-Qy" -Identify the versions of each tool used by the compiler, in a -\&\f(CW\*(C`.ident\*(C'\fR assembler directive in the output. -.Ip "\fB\-Qn\fR" 4 -.IX Item "-Qn" -Refrain from adding \f(CW\*(C`.ident\*(C'\fR directives to the output file (this is -the default). -.Ip "\fB\-YP,\fR\fIdirs\fR" 4 -.IX Item "-YP,dirs" -Search the directories \fIdirs\fR, and no others, for libraries -specified with \fB\-l\fR. -.Ip "\fB\-Ym,\fR\fIdir\fR" 4 -.IX Item "-Ym,dir" -Look in the directory \fIdir\fR to find the M4 preprocessor. -The assembler uses this option. -.PP -.I "TMS320C3x/C4x Options" -.IX Subsection "TMS320C3x/C4x Options" -.PP -These \fB\-m\fR options are defined for TMS320C3x/C4x implementations: -.Ip "\fB\-mcpu=\fR\fIcpu_type\fR" 4 -.IX Item "-mcpu=cpu_type" -Set the instruction set, register set, and instruction scheduling -parameters for machine type \fIcpu_type\fR. Supported values for -\&\fIcpu_type\fR are \fBc30\fR, \fBc31\fR, \fBc32\fR, \fBc40\fR, and -\&\fBc44\fR. The default is \fBc40\fR to generate code for the -\&\s-1TMS320C40\s0. -.Ip "\fB\-mbig-memory\fR" 4 -.IX Item "-mbig-memory" -.PD 0 -.Ip "\fB\-mbig\fR" 4 -.IX Item "-mbig" -.Ip "\fB\-msmall-memory\fR" 4 -.IX Item "-msmall-memory" -.Ip "\fB\-msmall\fR" 4 -.IX Item "-msmall" -.PD -Generates code for the big or small memory model. The small memory -model assumed that all data fits into one 64K word page. At run-time -the data page (\s-1DP\s0) register must be set to point to the 64K page -containing the .bss and .data program sections. The big memory model is -the default and requires reloading of the \s-1DP\s0 register for every direct -memory access. -.Ip "\fB\-mbk\fR" 4 -.IX Item "-mbk" -.PD 0 -.Ip "\fB\-mno-bk\fR" 4 -.IX Item "-mno-bk" -.PD -Allow (disallow) allocation of general integer operands into the block -count register \s-1BK\s0. -.Ip "\fB\-mdb\fR" 4 -.IX Item "-mdb" -.PD 0 -.Ip "\fB\-mno-db\fR" 4 -.IX Item "-mno-db" -.PD -Enable (disable) generation of code using decrement and branch, -\&\fIDBcond\fR\|(D), instructions. This is enabled by default for the C4x. To be -on the safe side, this is disabled for the C3x, since the maximum -iteration count on the C3x is 2^{23 + 1} (but who iterates loops more than -2^{23} times on the C3x?). Note that \s-1GCC\s0 will try to reverse a loop so -that it can utilise the decrement and branch instruction, but will give -up if there is more than one memory reference in the loop. Thus a loop -where the loop counter is decremented can generate slightly more -efficient code, in cases where the \s-1RPTB\s0 instruction cannot be utilised. -.Ip "\fB\-mdp-isr-reload\fR" 4 -.IX Item "-mdp-isr-reload" -.PD 0 -.Ip "\fB\-mparanoid\fR" 4 -.IX Item "-mparanoid" -.PD -Force the \s-1DP\s0 register to be saved on entry to an interrupt service -routine (\s-1ISR\s0), reloaded to point to the data section, and restored on -exit from the \s-1ISR\s0. This should not be required unless someone has -violated the small memory model by modifying the \s-1DP\s0 register, say within -an object library. -.Ip "\fB\-mmpyi\fR" 4 -.IX Item "-mmpyi" -.PD 0 -.Ip "\fB\-mno-mpyi\fR" 4 -.IX Item "-mno-mpyi" -.PD -For the C3x use the 24\-bit \s-1MPYI\s0 instruction for integer multiplies -instead of a library call to guarantee 32\-bit results. Note that if one -of the operands is a constant, then the multiplication will be performed -using shifts and adds. If the \fB\-mmpyi\fR option is not specified for the C3x, -then squaring operations are performed inline instead of a library call. -.Ip "\fB\-mfast-fix\fR" 4 -.IX Item "-mfast-fix" -.PD 0 -.Ip "\fB\-mno-fast-fix\fR" 4 -.IX Item "-mno-fast-fix" -.PD -The C3x/C4x \s-1FIX\s0 instruction to convert a floating point value to an -integer value chooses the nearest integer less than or equal to the -floating point value rather than to the nearest integer. Thus if the -floating point number is negative, the result will be incorrectly -truncated an additional code is necessary to detect and correct this -case. This option can be used to disable generation of the additional -code required to correct the result. -.Ip "\fB\-mrptb\fR" 4 -.IX Item "-mrptb" -.PD 0 -.Ip "\fB\-mno-rptb\fR" 4 -.IX Item "-mno-rptb" -.PD -Enable (disable) generation of repeat block sequences using the \s-1RPTB\s0 -instruction for zero overhead looping. The \s-1RPTB\s0 construct is only used -for innermost loops that do not call functions or jump across the loop -boundaries. There is no advantage having nested \s-1RPTB\s0 loops due to the -overhead required to save and restore the \s-1RC\s0, \s-1RS\s0, and \s-1RE\s0 registers. -This is enabled by default with \fB\-O2\fR. -.Ip "\fB\-mrpts=\fR\fIcount\fR" 4 -.IX Item "-mrpts=count" -.PD 0 -.Ip "\fB\-mno-rpts\fR" 4 -.IX Item "-mno-rpts" -.PD -Enable (disable) the use of the single instruction repeat instruction -\&\s-1RPTS\s0. If a repeat block contains a single instruction, and the loop -count can be guaranteed to be less than the value \fIcount\fR, \s-1GCC\s0 will -emit a \s-1RPTS\s0 instruction instead of a \s-1RPTB\s0. If no value is specified, -then a \s-1RPTS\s0 will be emitted even if the loop count cannot be determined -at compile time. Note that the repeated instruction following \s-1RPTS\s0 does -not have to be reloaded from memory each iteration, thus freeing up the -\&\s-1CPU\s0 buses for operands. However, since interrupts are blocked by this -instruction, it is disabled by default. -.Ip "\fB\-mloop-unsigned\fR" 4 -.IX Item "-mloop-unsigned" -.PD 0 -.Ip "\fB\-mno-loop-unsigned\fR" 4 -.IX Item "-mno-loop-unsigned" -.PD -The maximum iteration count when using \s-1RPTS\s0 and \s-1RPTB\s0 (and \s-1DB\s0 on the C40) -is 2^{31 + 1} since these instructions test if the iteration count is -negative to terminate the loop. If the iteration count is unsigned -there is a possibility than the 2^{31 + 1} maximum iteration count may be -exceeded. This switch allows an unsigned iteration count. -.Ip "\fB\-mti\fR" 4 -.IX Item "-mti" -Try to emit an assembler syntax that the \s-1TI\s0 assembler (asm30) is happy -with. This also enforces compatibility with the \s-1API\s0 employed by the \s-1TI\s0 -C3x C compiler. For example, long doubles are passed as structures -rather than in floating point registers. -.Ip "\fB\-mregparm\fR" 4 -.IX Item "-mregparm" -.PD 0 -.Ip "\fB\-mmemparm\fR" 4 -.IX Item "-mmemparm" -.PD -Generate code that uses registers (stack) for passing arguments to functions. -By default, arguments are passed in registers where possible rather -than by pushing arguments on to the stack. -.Ip "\fB\-mparallel-insns\fR" 4 -.IX Item "-mparallel-insns" -.PD 0 -.Ip "\fB\-mno-parallel-insns\fR" 4 -.IX Item "-mno-parallel-insns" -.PD -Allow the generation of parallel instructions. This is enabled by -default with \fB\-O2\fR. -.Ip "\fB\-mparallel-mpy\fR" 4 -.IX Item "-mparallel-mpy" -.PD 0 -.Ip "\fB\-mno-parallel-mpy\fR" 4 -.IX Item "-mno-parallel-mpy" -.PD -Allow the generation of MPY||ADD and MPY||SUB parallel instructions, -provided \fB\-mparallel-insns\fR is also specified. These instructions have -tight register constraints which can pessimize the code generation -of large functions. -.PP -.I "V850 Options" -.IX Subsection "V850 Options" -.PP -These \fB\-m\fR options are defined for V850 implementations: -.Ip "\fB\-mlong-calls\fR" 4 -.IX Item "-mlong-calls" -.PD 0 -.Ip "\fB\-mno-long-calls\fR" 4 -.IX Item "-mno-long-calls" -.PD -Treat all calls as being far away (near). If calls are assumed to be -far away, the compiler will always load the functions address up into a -register, and call indirect through the pointer. -.Ip "\fB\-mno-ep\fR" 4 -.IX Item "-mno-ep" -.PD 0 -.Ip "\fB\-mep\fR" 4 -.IX Item "-mep" -.PD -Do not optimize (do optimize) basic blocks that use the same index -pointer 4 or more times to copy pointer into the \f(CW\*(C`ep\*(C'\fR register, and -use the shorter \f(CW\*(C`sld\*(C'\fR and \f(CW\*(C`sst\*(C'\fR instructions. The \fB\-mep\fR -option is on by default if you optimize. -.Ip "\fB\-mno-prolog-function\fR" 4 -.IX Item "-mno-prolog-function" -.PD 0 -.Ip "\fB\-mprolog-function\fR" 4 -.IX Item "-mprolog-function" -.PD -Do not use (do use) external functions to save and restore registers at -the prolog and epilog of a function. The external functions are slower, -but use less code space if more than one function saves the same number -of registers. The \fB\-mprolog-function\fR option is on by default if -you optimize. -.Ip "\fB\-mspace\fR" 4 -.IX Item "-mspace" -Try to make the code as small as possible. At present, this just turns -on the \fB\-mep\fR and \fB\-mprolog-function\fR options. -.Ip "\fB\-mtda=\fR\fIn\fR" 4 -.IX Item "-mtda=n" -Put static or global variables whose size is \fIn\fR bytes or less into -the tiny data area that register \f(CW\*(C`ep\*(C'\fR points to. The tiny data -area can hold up to 256 bytes in total (128 bytes for byte references). -.Ip "\fB\-msda=\fR\fIn\fR" 4 -.IX Item "-msda=n" -Put static or global variables whose size is \fIn\fR bytes or less into -the small data area that register \f(CW\*(C`gp\*(C'\fR points to. The small data -area can hold up to 64 kilobytes. -.Ip "\fB\-mzda=\fR\fIn\fR" 4 -.IX Item "-mzda=n" -Put static or global variables whose size is \fIn\fR bytes or less into -the first 32 kilobytes of memory. -.Ip "\fB\-mv850\fR" 4 -.IX Item "-mv850" -Specify that the target processor is the V850. -.Ip "\fB\-mbig-switch\fR" 4 -.IX Item "-mbig-switch" -Generate code suitable for big switch tables. Use this option only if -the assembler/linker complain about out of range branches within a switch -table. -.PP -.I "\s-1ARC\s0 Options" -.IX Subsection "ARC Options" -.PP -These options are defined for \s-1ARC\s0 implementations: -.Ip "\fB\-EL\fR" 4 -.IX Item "-EL" -Compile code for little endian mode. This is the default. -.Ip "\fB\-EB\fR" 4 -.IX Item "-EB" -Compile code for big endian mode. -.Ip "\fB\-mmangle-cpu\fR" 4 -.IX Item "-mmangle-cpu" -Prepend the name of the cpu to all public symbol names. -In multiple-processor systems, there are many \s-1ARC\s0 variants with different -instruction and register set characteristics. This flag prevents code -compiled for one cpu to be linked with code compiled for another. -No facility exists for handling variants that are ``almost identical''. -This is an all or nothing option. -.Ip "\fB\-mcpu=\fR\fIcpu\fR" 4 -.IX Item "-mcpu=cpu" -Compile code for \s-1ARC\s0 variant \fIcpu\fR. -Which variants are supported depend on the configuration. -All variants support \fB\-mcpu=base\fR, this is the default. -.Ip "\fB\-mtext=\fR\fItext-section\fR" 4 -.IX Item "-mtext=text-section" -.PD 0 -.Ip "\fB\-mdata=\fR\fIdata-section\fR" 4 -.IX Item "-mdata=data-section" -.Ip "\fB\-mrodata=\fR\fIreadonly-data-section\fR" 4 -.IX Item "-mrodata=readonly-data-section" -.PD -Put functions, data, and readonly data in \fItext-section\fR, -\&\fIdata-section\fR, and \fIreadonly-data-section\fR respectively -by default. This can be overridden with the \f(CW\*(C`section\*(C'\fR attribute. -.PP -.I "\s-1NS32K\s0 Options" -.IX Subsection "NS32K Options" -.PP -These are the \fB\-m\fR options defined for the 32000 series. The default -values for these options depends on which style of 32000 was selected when -the compiler was configured; the defaults for the most common choices are -given below. -.Ip "\fB\-m32032\fR" 4 -.IX Item "-m32032" -.PD 0 -.Ip "\fB\-m32032\fR" 4 -.IX Item "-m32032" -.PD -Generate output for a 32032. This is the default -when the compiler is configured for 32032 and 32016 based systems. -.Ip "\fB\-m32332\fR" 4 -.IX Item "-m32332" -.PD 0 -.Ip "\fB\-m32332\fR" 4 -.IX Item "-m32332" -.PD -Generate output for a 32332. This is the default -when the compiler is configured for 32332\-based systems. -.Ip "\fB\-m32532\fR" 4 -.IX Item "-m32532" -.PD 0 -.Ip "\fB\-m32532\fR" 4 -.IX Item "-m32532" -.PD -Generate output for a 32532. This is the default -when the compiler is configured for 32532\-based systems. -.Ip "\fB\-m32081\fR" 4 -.IX Item "-m32081" -Generate output containing 32081 instructions for floating point. -This is the default for all systems. -.Ip "\fB\-m32381\fR" 4 -.IX Item "-m32381" -Generate output containing 32381 instructions for floating point. This -also implies \fB\-m32081\fR. The 32381 is only compatible with the 32332 -and 32532 cpus. This is the default for the pc532\-netbsd configuration. -.Ip "\fB\-mmulti-add\fR" 4 -.IX Item "-mmulti-add" -Try and generate multiply-add floating point instructions \f(CW\*(C`polyF\*(C'\fR -and \f(CW\*(C`dotF\*(C'\fR. This option is only available if the \fB\-m32381\fR -option is in effect. Using these instructions requires changes to -register allocation which generally has a negative impact on -performance. This option should only be enabled when compiling code -particularly likely to make heavy use of multiply-add instructions. -.Ip "\fB\-mnomulti-add\fR" 4 -.IX Item "-mnomulti-add" -Do not try and generate multiply-add floating point instructions -\&\f(CW\*(C`polyF\*(C'\fR and \f(CW\*(C`dotF\*(C'\fR. This is the default on all platforms. -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -Generate output containing library calls for floating point. -\&\fBWarning:\fR the requisite libraries may not be available. -.Ip "\fB\-mnobitfield\fR" 4 -.IX Item "-mnobitfield" -Do not use the bit-field instructions. On some machines it is faster to -use shifting and masking operations. This is the default for the pc532. -.Ip "\fB\-mbitfield\fR" 4 -.IX Item "-mbitfield" -Do use the bit-field instructions. This is the default for all platforms -except the pc532. -.Ip "\fB\-mrtd\fR" 4 -.IX Item "-mrtd" -Use a different function-calling convention, in which functions -that take a fixed number of arguments return pop their -arguments on return with the \f(CW\*(C`ret\*(C'\fR instruction. -.Sp -This calling convention is incompatible with the one normally -used on Unix, so you cannot use it if you need to call libraries -compiled with the Unix compiler. -.Sp -Also, you must provide function prototypes for all functions that -take variable numbers of arguments (including \f(CW\*(C`printf\*(C'\fR); -otherwise incorrect code will be generated for calls to those -functions. -.Sp -In addition, seriously incorrect code will result if you call a -function with too many arguments. (Normally, extra arguments are -harmlessly ignored.) -.Sp -This option takes its name from the 680x0 \f(CW\*(C`rtd\*(C'\fR instruction. -.Ip "\fB\-mregparam\fR" 4 -.IX Item "-mregparam" -Use a different function-calling convention where the first two arguments -are passed in registers. -.Sp -This calling convention is incompatible with the one normally -used on Unix, so you cannot use it if you need to call libraries -compiled with the Unix compiler. -.Ip "\fB\-mnoregparam\fR" 4 -.IX Item "-mnoregparam" -Do not pass any arguments in registers. This is the default for all -targets. -.Ip "\fB\-msb\fR" 4 -.IX Item "-msb" -It is \s-1OK\s0 to use the sb as an index register which is always loaded with -zero. This is the default for the pc532\-netbsd target. -.Ip "\fB\-mnosb\fR" 4 -.IX Item "-mnosb" -The sb register is not available for use or has not been initialized to -zero by the run time system. This is the default for all targets except -the pc532\-netbsd. It is also implied whenever \fB\-mhimem\fR or -\&\fB\-fpic\fR is set. -.Ip "\fB\-mhimem\fR" 4 -.IX Item "-mhimem" -Many ns32000 series addressing modes use displacements of up to 512MB. -If an address is above 512MB then displacements from zero can not be used. -This option causes code to be generated which can be loaded above 512MB. -This may be useful for operating systems or \s-1ROM\s0 code. -.Ip "\fB\-mnohimem\fR" 4 -.IX Item "-mnohimem" -Assume code will be loaded in the first 512MB of virtual address space. -This is the default for all platforms. -.PP -.I "\s-1AVR\s0 Options" -.IX Subsection "AVR Options" -.PP -These options are defined for \s-1AVR\s0 implementations: -.Ip "\fB\-mmcu=\fR\fImcu\fR" 4 -.IX Item "-mmcu=mcu" -Specify \s-1ATMEL\s0 \s-1AVR\s0 instruction set or \s-1MCU\s0 type. -.Sp -Instruction set avr1 is for the minimal \s-1AVR\s0 core, not supported by the C -compiler, only for assembler programs (\s-1MCU\s0 types: at90s1200, attiny10, -attiny11, attiny12, attiny15, attiny28). -.Sp -Instruction set avr2 (default) is for the classic \s-1AVR\s0 core with up to -8K program memory space (\s-1MCU\s0 types: at90s2313, at90s2323, attiny22, -at90s2333, at90s2343, at90s4414, at90s4433, at90s4434, at90s8515, -at90c8534, at90s8535). -.Sp -Instruction set avr3 is for the classic \s-1AVR\s0 core with up to 128K program -memory space (\s-1MCU\s0 types: atmega103, atmega603, at43usb320, at76c711). -.Sp -Instruction set avr4 is for the enhanced \s-1AVR\s0 core with up to 8K program -memory space (\s-1MCU\s0 types: atmega8, atmega83, atmega85). -.Sp -Instruction set avr5 is for the enhanced \s-1AVR\s0 core with up to 128K program -memory space (\s-1MCU\s0 types: atmega16, atmega161, atmega163, atmega32, atmega323, -atmega64, atmega128, at43usb355, at94k). -.Ip "\fB\-msize\fR" 4 -.IX Item "-msize" -Output instruction sizes to the asm file. -.Ip "\fB\-minit-stack=\fR\fIN\fR" 4 -.IX Item "-minit-stack=N" -Specify the initial stack address, which may be a symbol or numeric value, -\&\fB_\|_stack\fR is the default. -.Ip "\fB\-mno-interrupts\fR" 4 -.IX Item "-mno-interrupts" -Generated code is not compatible with hardware interrupts. -Code size will be smaller. -.Ip "\fB\-mcall-prologues\fR" 4 -.IX Item "-mcall-prologues" -Functions prologues/epilogues expanded as call to appropriate -subroutines. Code size will be smaller. -.Ip "\fB\-mno-tablejump\fR" 4 -.IX Item "-mno-tablejump" -Do not generate tablejump insns which sometimes increase code size. -.Ip "\fB\-mtiny-stack\fR" 4 -.IX Item "-mtiny-stack" -Change only the low 8 bits of the stack pointer. -.PP -.I "MCore Options" -.IX Subsection "MCore Options" -.PP -These are the \fB\-m\fR options defined for the Motorola M*Core -processors. -.Ip "\fB\-mhardlit\fR" 4 -.IX Item "-mhardlit" -.PD 0 -.Ip "\fB\-mhardlit\fR" 4 -.IX Item "-mhardlit" -.Ip "\fB\-mno-hardlit\fR" 4 -.IX Item "-mno-hardlit" -.PD -Inline constants into the code stream if it can be done in two -instructions or less. -.Ip "\fB\-mdiv\fR" 4 -.IX Item "-mdiv" -.PD 0 -.Ip "\fB\-mdiv\fR" 4 -.IX Item "-mdiv" -.Ip "\fB\-mno-div\fR" 4 -.IX Item "-mno-div" -.PD -Use the divide instruction. (Enabled by default). -.Ip "\fB\-mrelax-immediate\fR" 4 -.IX Item "-mrelax-immediate" -.PD 0 -.Ip "\fB\-mrelax-immediate\fR" 4 -.IX Item "-mrelax-immediate" -.Ip "\fB\-mno-relax-immediate\fR" 4 -.IX Item "-mno-relax-immediate" -.PD -Allow arbitrary sized immediates in bit operations. -.Ip "\fB\-mwide-bitfields\fR" 4 -.IX Item "-mwide-bitfields" -.PD 0 -.Ip "\fB\-mwide-bitfields\fR" 4 -.IX Item "-mwide-bitfields" -.Ip "\fB\-mno-wide-bitfields\fR" 4 -.IX Item "-mno-wide-bitfields" -.PD -Always treat bit-fields as int-sized. -.Ip "\fB\-m4byte-functions\fR" 4 -.IX Item "-m4byte-functions" -.PD 0 -.Ip "\fB\-m4byte-functions\fR" 4 -.IX Item "-m4byte-functions" -.Ip "\fB\-mno-4byte-functions\fR" 4 -.IX Item "-mno-4byte-functions" -.PD -Force all functions to be aligned to a four byte boundary. -.Ip "\fB\-mcallgraph-data\fR" 4 -.IX Item "-mcallgraph-data" -.PD 0 -.Ip "\fB\-mcallgraph-data\fR" 4 -.IX Item "-mcallgraph-data" -.Ip "\fB\-mno-callgraph-data\fR" 4 -.IX Item "-mno-callgraph-data" -.PD -Emit callgraph information. -.Ip "\fB\-mslow-bytes\fR" 4 -.IX Item "-mslow-bytes" -.PD 0 -.Ip "\fB\-mslow-bytes\fR" 4 -.IX Item "-mslow-bytes" -.Ip "\fB\-mno-slow-bytes\fR" 4 -.IX Item "-mno-slow-bytes" -.PD -Prefer word access when reading byte quantities. -.Ip "\fB\-mlittle-endian\fR" 4 -.IX Item "-mlittle-endian" -.PD 0 -.Ip "\fB\-mlittle-endian\fR" 4 -.IX Item "-mlittle-endian" -.Ip "\fB\-mbig-endian\fR" 4 -.IX Item "-mbig-endian" -.PD -Generate code for a little endian target. -.Ip "\fB\-m210\fR" 4 -.IX Item "-m210" -.PD 0 -.Ip "\fB\-m210\fR" 4 -.IX Item "-m210" -.Ip "\fB\-m340\fR" 4 -.IX Item "-m340" -.PD -Generate code for the 210 processor. -.PP -.I "\s-1IA-64\s0 Options" -.IX Subsection "IA-64 Options" -.PP -These are the \fB\-m\fR options defined for the Intel \s-1IA-64\s0 architecture. -.Ip "\fB\-mbig-endian\fR" 4 -.IX Item "-mbig-endian" -Generate code for a big endian target. This is the default for \s-1HPUX\s0. -.Ip "\fB\-mlittle-endian\fR" 4 -.IX Item "-mlittle-endian" -Generate code for a little endian target. This is the default for \s-1AIX5\s0 -and Linux. -.Ip "\fB\-mgnu-as\fR" 4 -.IX Item "-mgnu-as" -.PD 0 -.Ip "\fB\-mno-gnu-as\fR" 4 -.IX Item "-mno-gnu-as" -.PD -Generate (or don't) code for the \s-1GNU\s0 assembler. This is the default. -.Ip "\fB\-mgnu-ld\fR" 4 -.IX Item "-mgnu-ld" -.PD 0 -.Ip "\fB\-mno-gnu-ld\fR" 4 -.IX Item "-mno-gnu-ld" -.PD -Generate (or don't) code for the \s-1GNU\s0 linker. This is the default. -.Ip "\fB\-mno-pic\fR" 4 -.IX Item "-mno-pic" -Generate code that does not use a global pointer register. The result -is not position independent code, and violates the \s-1IA-64\s0 \s-1ABI\s0. -.Ip "\fB\-mvolatile-asm-stop\fR" 4 -.IX Item "-mvolatile-asm-stop" -.PD 0 -.Ip "\fB\-mno-volatile-asm-stop\fR" 4 -.IX Item "-mno-volatile-asm-stop" -.PD -Generate (or don't) a stop bit immediately before and after volatile asm -statements. -.Ip "\fB\-mb-step\fR" 4 -.IX Item "-mb-step" -Generate code that works around Itanium B step errata. -.Ip "\fB\-mregister-names\fR" 4 -.IX Item "-mregister-names" -.PD 0 -.Ip "\fB\-mno-register-names\fR" 4 -.IX Item "-mno-register-names" -.PD -Generate (or don't) \fBin\fR, \fBloc\fR, and \fBout\fR register names for -the stacked registers. This may make assembler output more readable. -.Ip "\fB\-mno-sdata\fR" 4 -.IX Item "-mno-sdata" -.PD 0 -.Ip "\fB\-msdata\fR" 4 -.IX Item "-msdata" -.PD -Disable (or enable) optimizations that use the small data section. This may -be useful for working around optimizer bugs. -.Ip "\fB\-mconstant-gp\fR" 4 -.IX Item "-mconstant-gp" -Generate code that uses a single constant global pointer value. This is -useful when compiling kernel code. -.Ip "\fB\-mauto-pic\fR" 4 -.IX Item "-mauto-pic" -Generate code that is self-relocatable. This implies \fB\-mconstant-gp\fR. -This is useful when compiling firmware code. -.Ip "\fB\-minline-divide-min-latency\fR" 4 -.IX Item "-minline-divide-min-latency" -Generate code for inline divides using the minimum latency algorithm. -.Ip "\fB\-minline-divide-max-throughput\fR" 4 -.IX Item "-minline-divide-max-throughput" -Generate code for inline divides using the maximum throughput algorithm. -.Ip "\fB\-mno-dwarf2\-asm\fR" 4 -.IX Item "-mno-dwarf2-asm" -.PD 0 -.Ip "\fB\-mdwarf2\-asm\fR" 4 -.IX Item "-mdwarf2-asm" -.PD -Don't (or do) generate assembler code for the \s-1DWARF2\s0 line number debugging -info. This may be useful when not using the \s-1GNU\s0 assembler. -.Ip "\fB\-mfixed-range=\fR\fIregister-range\fR" 4 -.IX Item "-mfixed-range=register-range" -Generate code treating the given register range as fixed registers. -A fixed register is one that the register allocator can not use. This is -useful when compiling kernel code. A register range is specified as -two registers separated by a dash. Multiple register ranges can be -specified separated by a comma. -.PP -.I "D30V Options" -.IX Subsection "D30V Options" -.PP -These \fB\-m\fR options are defined for D30V implementations: -.Ip "\fB\-mextmem\fR" 4 -.IX Item "-mextmem" -Link the \fB.text\fR, \fB.data\fR, \fB.bss\fR, \fB.strings\fR, -\&\fB.rodata\fR, \fB.rodata1\fR, \fB.data1\fR sections into external -memory, which starts at location \f(CW\*(C`0x80000000\*(C'\fR. -.Ip "\fB\-mextmemory\fR" 4 -.IX Item "-mextmemory" -Same as the \fB\-mextmem\fR switch. -.Ip "\fB\-monchip\fR" 4 -.IX Item "-monchip" -Link the \fB.text\fR section into onchip text memory, which starts at -location \f(CW\*(C`0x0\*(C'\fR. Also link \fB.data\fR, \fB.bss\fR, -\&\fB.strings\fR, \fB.rodata\fR, \fB.rodata1\fR, \fB.data1\fR sections -into onchip data memory, which starts at location \f(CW\*(C`0x20000000\*(C'\fR. -.Ip "\fB\-mno-asm-optimize\fR" 4 -.IX Item "-mno-asm-optimize" -.PD 0 -.Ip "\fB\-masm-optimize\fR" 4 -.IX Item "-masm-optimize" -.PD -Disable (enable) passing \fB\-O\fR to the assembler when optimizing. -The assembler uses the \fB\-O\fR option to automatically parallelize -adjacent short instructions where possible. -.Ip "\fB\-mbranch-cost=\fR\fIn\fR" 4 -.IX Item "-mbranch-cost=n" -Increase the internal costs of branches to \fIn\fR. Higher costs means -that the compiler will issue more instructions to avoid doing a branch. -The default is 2. -.Ip "\fB\-mcond-exec=\fR\fIn\fR" 4 -.IX Item "-mcond-exec=n" -Specify the maximum number of conditionally executed instructions that -replace a branch. The default is 4. -.PP -.I "S/390 and zSeries Options" -.IX Subsection "S/390 and zSeries Options" -.PP -These are the \fB\-m\fR options defined for the S/390 and zSeries architecture. -.Ip "\fB\-mhard-float\fR" 4 -.IX Item "-mhard-float" -.PD 0 -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -.PD -Use (do not use) the hardware floating-point instructions and registers -for floating-point operations. When \fB\-msoft-float\fR is specified, -functions in \fIlibgcc.a\fR will be used to perform floating-point -operations. When \fB\-mhard-float\fR is specified, the compiler -generates \s-1IEEE\s0 floating-point instructions. This is the default. -.Ip "\fB\-mbackchain\fR" 4 -.IX Item "-mbackchain" -.PD 0 -.Ip "\fB\-mno-backchain\fR" 4 -.IX Item "-mno-backchain" -.PD -Generate (or do not generate) code which maintains an explicit -backchain within the stack frame that points to the caller's frame. -This is currently needed to allow debugging. The default is to -generate the backchain. -.Ip "\fB\-msmall-exec\fR" 4 -.IX Item "-msmall-exec" -.PD 0 -.Ip "\fB\-mno-small-exec\fR" 4 -.IX Item "-mno-small-exec" -.PD -Generate (or do not generate) code using the \f(CW\*(C`bras\*(C'\fR instruction -to do subroutine calls. -This only works reliably if the total executable size does not -exceed 64k. The default is to use the \f(CW\*(C`basr\*(C'\fR instruction instead, -which does not have this limitation. -.Ip "\fB\-m64\fR" 4 -.IX Item "-m64" -.PD 0 -.Ip "\fB\-m31\fR" 4 -.IX Item "-m31" -.PD -When \fB\-m31\fR is specified, generate code compliant to the -Linux for S/390 \s-1ABI\s0. When \fB\-m64\fR is specified, generate -code compliant to the Linux for zSeries \s-1ABI\s0. This allows \s-1GCC\s0 in -particular to generate 64\-bit instructions. For the \fBs390\fR -targets, the default is \fB\-m31\fR, while the \fBs390x\fR -targets default to \fB\-m64\fR. -.Ip "\fB\-mmvcle\fR" 4 -.IX Item "-mmvcle" -.PD 0 -.Ip "\fB\-mno-mvcle\fR" 4 -.IX Item "-mno-mvcle" -.PD -Generate (or do not generate) code using the \f(CW\*(C`mvcle\*(C'\fR instruction -to perform block moves. When \fB\-mno-mvcle\fR is specifed, -use a \f(CW\*(C`mvc\*(C'\fR loop instead. This is the default. -.Ip "\fB\-mdebug\fR" 4 -.IX Item "-mdebug" -.PD 0 -.Ip "\fB\-mno-debug\fR" 4 -.IX Item "-mno-debug" -.PD -Print (or do not print) additional debug information when compiling. -The default is to not print debug information. -.PP -.I "\s-1CRIS\s0 Options" -.IX Subsection "CRIS Options" -.PP -These options are defined specifically for the \s-1CRIS\s0 ports. -.Ip "\fB\-march=\fR\fIarchitecture-type\fR" 4 -.IX Item "-march=architecture-type" -.PD 0 -.Ip "\fB\-mcpu=\fR\fIarchitecture-type\fR" 4 -.IX Item "-mcpu=architecture-type" -.PD -Generate code for the specified architecture. The choices for -\&\fIarchitecture-type\fR are \fBv3\fR, \fBv8\fR and \fBv10\fR for -respectively \s-1ETRAX\s0\ 4, \s-1ETRAX\s0\ 100, and \s-1ETRAX\s0\ 100\ \s-1LX\s0. -Default is \fBv0\fR except for cris-axis-linux-gnu, where the default is -\&\fBv10\fR. -.Ip "\fB\-mtune=\fR\fIarchitecture-type\fR" 4 -.IX Item "-mtune=architecture-type" -Tune to \fIarchitecture-type\fR everything applicable about the generated -code, except for the \s-1ABI\s0 and the set of available instructions. The -choices for \fIarchitecture-type\fR are the same as for -\&\fB\-march=\fR\fIarchitecture-type\fR. -.Ip "\fB\-mmax-stack-frame=\fR\fIn\fR" 4 -.IX Item "-mmax-stack-frame=n" -Warn when the stack frame of a function exceeds \fIn\fR bytes. -.Ip "\fB\-melinux-stacksize=\fR\fIn\fR" 4 -.IX Item "-melinux-stacksize=n" -Only available with the \fBcris-axis-aout\fR target. Arranges for -indications in the program to the kernel loader that the stack of the -program should be set to \fIn\fR bytes. -.Ip "\fB\-metrax4\fR" 4 -.IX Item "-metrax4" -.PD 0 -.Ip "\fB\-metrax100\fR" 4 -.IX Item "-metrax100" -.PD -The options \fB\-metrax4\fR and \fB\-metrax100\fR are synonyms for -\&\fB\-march=v3\fR and \fB\-march=v8\fR respectively. -.Ip "\fB\-mpdebug\fR" 4 -.IX Item "-mpdebug" -Enable CRIS-specific verbose debug-related information in the assembly -code. This option also has the effect to turn off the \fB#NO_APP\fR -formatted-code indicator to the assembler at the beginning of the -assembly file. -.Ip "\fB\-mcc-init\fR" 4 -.IX Item "-mcc-init" -Do not use condition-code results from previous instruction; always emit -compare and test instructions before use of condition codes. -.Ip "\fB\-mno-side-effects\fR" 4 -.IX Item "-mno-side-effects" -Do not emit instructions with side-effects in addressing modes other than -post-increment. -.Ip "\fB\-mstack-align\fR" 4 -.IX Item "-mstack-align" -.PD 0 -.Ip "\fB\-mno-stack-align\fR" 4 -.IX Item "-mno-stack-align" -.Ip "\fB\-mdata-align\fR" 4 -.IX Item "-mdata-align" -.Ip "\fB\-mno-data-align\fR" 4 -.IX Item "-mno-data-align" -.Ip "\fB\-mconst-align\fR" 4 -.IX Item "-mconst-align" -.Ip "\fB\-mno-const-align\fR" 4 -.IX Item "-mno-const-align" -.PD -These options (no-options) arranges (eliminate arrangements) for the -stack-frame, individual data and constants to be aligned for the maximum -single data access size for the chosen \s-1CPU\s0 model. The default is to -arrange for 32\-bit alignment. \s-1ABI\s0 details such as structure layout are -not affected by these options. -.Ip "\fB\-m32\-bit\fR" 4 -.IX Item "-m32-bit" -.PD 0 -.Ip "\fB\-m16\-bit\fR" 4 -.IX Item "-m16-bit" -.Ip "\fB\-m8\-bit\fR" 4 -.IX Item "-m8-bit" -.PD -Similar to the stack- data- and const-align options above, these options -arrange for stack-frame, writable data and constants to all be 32\-bit, -16\-bit or 8\-bit aligned. The default is 32\-bit alignment. -.Ip "\fB\-mno-prologue-epilogue\fR" 4 -.IX Item "-mno-prologue-epilogue" -.PD 0 -.Ip "\fB\-mprologue-epilogue\fR" 4 -.IX Item "-mprologue-epilogue" -.PD -With \fB\-mno-prologue-epilogue\fR, the normal function prologue and -epilogue that sets up the stack-frame are omitted and no return -instructions or return sequences are generated in the code. Use this -option only together with visual inspection of the compiled code: no -warnings or errors are generated when call-saved registers must be saved, -or storage for local variable needs to be allocated. -.Ip "\fB\-mno-gotplt\fR" 4 -.IX Item "-mno-gotplt" -.PD 0 -.Ip "\fB\-mgotplt\fR" 4 -.IX Item "-mgotplt" -.PD -With \fB\-fpic\fR and \fB\-fPIC\fR, don't generate (do generate) -instruction sequences that load addresses for functions from the \s-1PLT\s0 part -of the \s-1GOT\s0 rather than (traditional on other architectures) calls to the -\&\s-1PLT\s0. The default is \fB\-mgotplt\fR. -.Ip "\fB\-maout\fR" 4 -.IX Item "-maout" -Legacy no-op option only recognized with the cris-axis-aout target. -.Ip "\fB\-melf\fR" 4 -.IX Item "-melf" -Legacy no-op option only recognized with the cris-axis-elf and -cris-axis-linux-gnu targets. -.Ip "\fB\-melinux\fR" 4 -.IX Item "-melinux" -Only recognized with the cris-axis-aout target, where it selects a -GNU/linux-like multilib, include files and instruction set for -\&\fB\-march=v8\fR. -.Ip "\fB\-mlinux\fR" 4 -.IX Item "-mlinux" -Legacy no-op option only recognized with the cris-axis-linux-gnu target. -.Ip "\fB\-sim\fR" 4 -.IX Item "-sim" -This option, recognized for the cris-axis-aout and cris-axis-elf arranges -to link with input-output functions from a simulator library. Code, -initialized data and zero-initialized data are allocated consecutively. -.Ip "\fB\-sim2\fR" 4 -.IX Item "-sim2" -Like \fB\-sim\fR, but pass linker options to locate initialized data at -0x40000000 and zero-initialized data at 0x80000000. -.PP -.I "\s-1MMIX\s0 Options" -.IX Subsection "MMIX Options" -.PP -These options are defined for the \s-1MMIX:\s0 -.Ip "\fB\-mlibfuncs\fR" 4 -.IX Item "-mlibfuncs" -.PD 0 -.Ip "\fB\-mno-libfuncs\fR" 4 -.IX Item "-mno-libfuncs" -.PD -Specify that intrinsic library functions are being compiled, passing all -values in registers, no matter the size. -.Ip "\fB\-mepsilon\fR" 4 -.IX Item "-mepsilon" -.PD 0 -.Ip "\fB\-mno-epsilon\fR" 4 -.IX Item "-mno-epsilon" -.PD -Generate floating-point comparison instructions that compare with respect -to the \f(CW\*(C`rE\*(C'\fR epsilon register. -.Ip "\fB\-mabi=mmixware\fR" 4 -.IX Item "-mabi=mmixware" -.PD 0 -.Ip "\fB\-mabi=gnu\fR" 4 -.IX Item "-mabi=gnu" -.PD -Generate code that passes function parameters and return values that (in -the called function) are seen as registers \f(CW\*(C`$0\*(C'\fR and up, as opposed to -the \s-1GNU\s0 \s-1ABI\s0 which uses global registers \f(CW\*(C`$231\*(C'\fR and up. -.Ip "\fB\-mzero-extend\fR" 4 -.IX Item "-mzero-extend" -.PD 0 -.Ip "\fB\-mno-zero-extend\fR" 4 -.IX Item "-mno-zero-extend" -.PD -When reading data from memory in sizes shorter than 64 bits, use (do not -use) zero-extending load instructions by default, rather than -sign-extending ones. -.Ip "\fB\-mknuthdiv\fR" 4 -.IX Item "-mknuthdiv" -.PD 0 -.Ip "\fB\-mno-knuthdiv\fR" 4 -.IX Item "-mno-knuthdiv" -.PD -Make the result of a division yielding a remainder have the same sign as -the divisor. With the default, \fB\-mno-knuthdiv\fR, the sign of the -remainder follows the sign of the dividend. Both methods are -arithmetically valid, the latter being almost exclusively used. -.Ip "\fB\-mtoplevel-symbols\fR" 4 -.IX Item "-mtoplevel-symbols" -.PD 0 -.Ip "\fB\-mno-toplevel-symbols\fR" 4 -.IX Item "-mno-toplevel-symbols" -.PD -Prepend (do not prepend) a \fB:\fR to all global symbols, so the assembly -code can be used with the \f(CW\*(C`PREFIX\*(C'\fR assembly directive. -.Ip "\fB\-melf\fR" 4 -.IX Item "-melf" -Generate an executable in the \s-1ELF\s0 format, rather than the default -\&\fBmmo\fR format used by the \fBmmix\fR simulator. -.Ip "\fB\-mbranch-predict\fR" 4 -.IX Item "-mbranch-predict" -.PD 0 -.Ip "\fB\-mno-branch-predict\fR" 4 -.IX Item "-mno-branch-predict" -.PD -Use (do not use) the probable-branch instructions, when static branch -prediction indicates a probable branch. -.Ip "\fB\-mbase-addresses\fR" 4 -.IX Item "-mbase-addresses" -.PD 0 -.Ip "\fB\-mno-base-addresses\fR" 4 -.IX Item "-mno-base-addresses" -.PD -Generate (do not generate) code that uses \fIbase addresses\fR. Using a -base address automatically generates a request (handled by the assembler -and the linker) for a constant to be set up in a global register. The -register is used for one or more base address requests within the range 0 -to 255 from the value held in the register. The generally leads to short -and fast code, but the number of different data items that can be -addressed is limited. This means that a program that uses lots of static -data may require \fB\-mno-base-addresses\fR. -.PP -.I "\s-1PDP-11\s0 Options" -.IX Subsection "PDP-11 Options" -.PP -These options are defined for the \s-1PDP-11:\s0 -.Ip "\fB\-mfpu\fR" 4 -.IX Item "-mfpu" -Use hardware \s-1FPP\s0 floating point. This is the default. (\s-1FIS\s0 floating -point on the \s-1PDP-11/40\s0 is not supported.) -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -Do not use hardware floating point. -.Ip "\fB\-mac0\fR" 4 -.IX Item "-mac0" -Return floating-point results in ac0 (fr0 in Unix assembler syntax). -.Ip "\fB\-mno-ac0\fR" 4 -.IX Item "-mno-ac0" -Return floating-point results in memory. This is the default. -.Ip "\fB\-m40\fR" 4 -.IX Item "-m40" -Generate code for a \s-1PDP-11/40\s0. -.Ip "\fB\-m45\fR" 4 -.IX Item "-m45" -Generate code for a \s-1PDP-11/45\s0. This is the default. -.Ip "\fB\-m10\fR" 4 -.IX Item "-m10" -Generate code for a \s-1PDP-11/10\s0. -.Ip "\fB\-mbcopy-builtin\fR" 4 -.IX Item "-mbcopy-builtin" -Use inline \f(CW\*(C`movstrhi\*(C'\fR patterns for copying memory. This is the -default. -.Ip "\fB\-mbcopy\fR" 4 -.IX Item "-mbcopy" -Do not use inline \f(CW\*(C`movstrhi\*(C'\fR patterns for copying memory. -.Ip "\fB\-mint16\fR" 4 -.IX Item "-mint16" -.PD 0 -.Ip "\fB\-mno-int32\fR" 4 -.IX Item "-mno-int32" -.PD -Use 16\-bit \f(CW\*(C`int\*(C'\fR. This is the default. -.Ip "\fB\-mint32\fR" 4 -.IX Item "-mint32" -.PD 0 -.Ip "\fB\-mno-int16\fR" 4 -.IX Item "-mno-int16" -.PD -Use 32\-bit \f(CW\*(C`int\*(C'\fR. -.Ip "\fB\-mfloat64\fR" 4 -.IX Item "-mfloat64" -.PD 0 -.Ip "\fB\-mno-float32\fR" 4 -.IX Item "-mno-float32" -.PD -Use 64\-bit \f(CW\*(C`float\*(C'\fR. This is the default. -.Ip "\fB\-mfloat32\fR" 4 -.IX Item "-mfloat32" -.PD 0 -.Ip "\fB\-mno-float64\fR" 4 -.IX Item "-mno-float64" -.PD -Use 32\-bit \f(CW\*(C`float\*(C'\fR. -.Ip "\fB\-mabshi\fR" 4 -.IX Item "-mabshi" -Use \f(CW\*(C`abshi2\*(C'\fR pattern. This is the default. -.Ip "\fB\-mno-abshi\fR" 4 -.IX Item "-mno-abshi" -Do not use \f(CW\*(C`abshi2\*(C'\fR pattern. -.Ip "\fB\-mbranch-expensive\fR" 4 -.IX Item "-mbranch-expensive" -Pretend that branches are expensive. This is for experimenting with -code generation only. -.Ip "\fB\-mbranch-cheap\fR" 4 -.IX Item "-mbranch-cheap" -Do not pretend that branches are expensive. This is the default. -.Ip "\fB\-msplit\fR" 4 -.IX Item "-msplit" -Generate code for a system with split I&D. -.Ip "\fB\-mno-split\fR" 4 -.IX Item "-mno-split" -Generate code for a system without split I&D. This is the default. -.Ip "\fB\-munix-asm\fR" 4 -.IX Item "-munix-asm" -Use Unix assembler syntax. This is the default when configured for -\&\fBpdp11\-*\-bsd\fR. -.Ip "\fB\-mdec-asm\fR" 4 -.IX Item "-mdec-asm" -Use \s-1DEC\s0 assembler syntax. This is the default when configured for any -\&\s-1PDP-11\s0 target other than \fBpdp11\-*\-bsd\fR. -.PP -.I "Xstormy16 Options" -.IX Subsection "Xstormy16 Options" -.PP -These options are defined for Xstormy16: -.Ip "\fB\-msim\fR" 4 -.IX Item "-msim" -Choose startup files and linker script suitable for the simulator. -.PP -.I "Xtensa Options" -.IX Subsection "Xtensa Options" -.PP -The Xtensa architecture is designed to support many different -configurations. The compiler's default options can be set to match a -particular Xtensa configuration by copying a configuration file into the -\&\s-1GCC\s0 sources when building \s-1GCC\s0. The options below may be used to -override the default options. -.Ip "\fB\-mbig-endian\fR" 4 -.IX Item "-mbig-endian" -.PD 0 -.Ip "\fB\-mlittle-endian\fR" 4 -.IX Item "-mlittle-endian" -.PD -Specify big-endian or little-endian byte ordering for the target Xtensa -processor. -.Ip "\fB\-mdensity\fR" 4 -.IX Item "-mdensity" -.PD 0 -.Ip "\fB\-mno-density\fR" 4 -.IX Item "-mno-density" -.PD -Enable or disable use of the optional Xtensa code density instructions. -.Ip "\fB\-mmac16\fR" 4 -.IX Item "-mmac16" -.PD 0 -.Ip "\fB\-mno-mac16\fR" 4 -.IX Item "-mno-mac16" -.PD -Enable or disable use of the Xtensa \s-1MAC16\s0 option. When enabled, \s-1GCC\s0 -will generate \s-1MAC16\s0 instructions from standard C code, with the -limitation that it will use neither the \s-1MR\s0 register file nor any -instruction that operates on the \s-1MR\s0 registers. When this option is -disabled, \s-1GCC\s0 will translate 16\-bit multiply/accumulate operations to a -combination of core instructions and library calls, depending on whether -any other multiplier options are enabled. -.Ip "\fB\-mmul16\fR" 4 -.IX Item "-mmul16" -.PD 0 -.Ip "\fB\-mno-mul16\fR" 4 -.IX Item "-mno-mul16" -.PD -Enable or disable use of the 16\-bit integer multiplier option. When -enabled, the compiler will generate 16\-bit multiply instructions for -multiplications of 16 bits or smaller in standard C code. When this -option is disabled, the compiler will either use 32\-bit multiply or -\&\s-1MAC16\s0 instructions if they are available or generate library calls to -perform the multiply operations using shifts and adds. -.Ip "\fB\-mmul32\fR" 4 -.IX Item "-mmul32" -.PD 0 -.Ip "\fB\-mno-mul32\fR" 4 -.IX Item "-mno-mul32" -.PD -Enable or disable use of the 32\-bit integer multiplier option. When -enabled, the compiler will generate 32\-bit multiply instructions for -multiplications of 32 bits or smaller in standard C code. When this -option is disabled, the compiler will generate library calls to perform -the multiply operations using either shifts and adds or 16\-bit multiply -instructions if they are available. -.Ip "\fB\-mnsa\fR" 4 -.IX Item "-mnsa" -.PD 0 -.Ip "\fB\-mno-nsa\fR" 4 -.IX Item "-mno-nsa" -.PD -Enable or disable use of the optional normalization shift amount -(\f(CW\*(C`NSA\*(C'\fR) instructions to implement the built-in \f(CW\*(C`ffs\*(C'\fR function. -.Ip "\fB\-mminmax\fR" 4 -.IX Item "-mminmax" -.PD 0 -.Ip "\fB\-mno-minmax\fR" 4 -.IX Item "-mno-minmax" -.PD -Enable or disable use of the optional minimum and maximum value -instructions. -.Ip "\fB\-msext\fR" 4 -.IX Item "-msext" -.PD 0 -.Ip "\fB\-mno-sext\fR" 4 -.IX Item "-mno-sext" -.PD -Enable or disable use of the optional sign extend (\f(CW\*(C`SEXT\*(C'\fR) -instruction. -.Ip "\fB\-mbooleans\fR" 4 -.IX Item "-mbooleans" -.PD 0 -.Ip "\fB\-mno-booleans\fR" 4 -.IX Item "-mno-booleans" -.PD -Enable or disable support for the boolean register file used by Xtensa -coprocessors. This is not typically useful by itself but may be -required for other options that make use of the boolean registers (e.g., -the floating-point option). -.Ip "\fB\-mhard-float\fR" 4 -.IX Item "-mhard-float" -.PD 0 -.Ip "\fB\-msoft-float\fR" 4 -.IX Item "-msoft-float" -.PD -Enable or disable use of the floating-point option. When enabled, \s-1GCC\s0 -generates floating-point instructions for 32\-bit \f(CW\*(C`float\*(C'\fR -operations. When this option is disabled, \s-1GCC\s0 generates library calls -to emulate 32\-bit floating-point operations using integer instructions. -Regardless of this option, 64\-bit \f(CW\*(C`double\*(C'\fR operations are always -emulated with calls to library functions. -.Ip "\fB\-mfused-madd\fR" 4 -.IX Item "-mfused-madd" -.PD 0 -.Ip "\fB\-mno-fused-madd\fR" 4 -.IX Item "-mno-fused-madd" -.PD -Enable or disable use of fused multiply/add and multiply/subtract -instructions in the floating-point option. This has no effect if the -floating-point option is not also enabled. Disabling fused multiply/add -and multiply/subtract instructions forces the compiler to use separate -instructions for the multiply and add/subtract operations. This may be -desirable in some cases where strict \s-1IEEE\s0 754\-compliant results are -required: the fused multiply add/subtract instructions do not round the -intermediate result, thereby producing results with \fImore\fR bits of -precision than specified by the \s-1IEEE\s0 standard. Disabling fused multiply -add/subtract instructions also ensures that the program output is not -sensitive to the compiler's ability to combine multiply and add/subtract -operations. -.Ip "\fB\-mserialize-volatile\fR" 4 -.IX Item "-mserialize-volatile" -.PD 0 -.Ip "\fB\-mno-serialize-volatile\fR" 4 -.IX Item "-mno-serialize-volatile" -.PD -When this option is enabled, \s-1GCC\s0 inserts \f(CW\*(C`MEMW\*(C'\fR instructions before -\&\f(CW\*(C`volatile\*(C'\fR memory references to guarantee sequential consistency. -The default is \fB\-mserialize-volatile\fR. Use -\&\fB\-mno-serialize-volatile\fR to omit the \f(CW\*(C`MEMW\*(C'\fR instructions. -.Ip "\fB\-mtext-section-literals\fR" 4 -.IX Item "-mtext-section-literals" -.PD 0 -.Ip "\fB\-mno-text-section-literals\fR" 4 -.IX Item "-mno-text-section-literals" -.PD -Control the treatment of literal pools. The default is -\&\fB\-mno-text-section-literals\fR, which places literals in a separate -section in the output file. This allows the literal pool to be placed -in a data \s-1RAM/ROM\s0, and it also allows the linker to combine literal -pools from separate object files to remove redundant literals and -improve code size. With \fB\-mtext-section-literals\fR, the literals -are interspersed in the text section in order to keep them as close as -possible to their references. This may be necessary for large assembly -files. -.Ip "\fB\-mtarget-align\fR" 4 -.IX Item "-mtarget-align" -.PD 0 -.Ip "\fB\-mno-target-align\fR" 4 -.IX Item "-mno-target-align" -.PD -When this option is enabled, \s-1GCC\s0 instructs the assembler to -automatically align instructions to reduce branch penalties at the -expense of some code density. The assembler attempts to widen density -instructions to align branch targets and the instructions following call -instructions. If there are not enough preceding safe density -instructions to align a target, no widening will be performed. The -default is \fB\-mtarget-align\fR. These options do not affect the -treatment of auto-aligned instructions like \f(CW\*(C`LOOP\*(C'\fR, which the -assembler will always align, either by widening density instructions or -by inserting no-op instructions. -.Ip "\fB\-mlongcalls\fR" 4 -.IX Item "-mlongcalls" -.PD 0 -.Ip "\fB\-mno-longcalls\fR" 4 -.IX Item "-mno-longcalls" -.PD -When this option is enabled, \s-1GCC\s0 instructs the assembler to translate -direct calls to indirect calls unless it can determine that the target -of a direct call is in the range allowed by the call instruction. This -translation typically occurs for calls to functions in other source -files. Specifically, the assembler translates a direct \f(CW\*(C`CALL\*(C'\fR -instruction into an \f(CW\*(C`L32R\*(C'\fR followed by a \f(CW\*(C`CALLX\*(C'\fR instruction. -The default is \fB\-mno-longcalls\fR. This option should be used in -programs where the call target can potentially be out of range. This -option is implemented in the assembler, not the compiler, so the -assembly code generated by \s-1GCC\s0 will still show direct call -instructions\-\-\-look at the disassembled object code to see the actual -instructions. Note that the assembler will use an indirect call for -every cross-file call, not just those that really will be out of range. -.Sh "Options for Code Generation Conventions" -.IX Subsection "Options for Code Generation Conventions" -These machine-independent options control the interface conventions -used in code generation. -.PP -Most of them have both positive and negative forms; the negative form -of \fB\-ffoo\fR would be \fB\-fno-foo\fR. In the table below, only -one of the forms is listed\-\-\-the one which is not the default. You -can figure out the other form by either removing \fBno-\fR or adding -it. -.Ip "\fB\-fexceptions\fR" 4 -.IX Item "-fexceptions" -Enable exception handling. Generates extra code needed to propagate -exceptions. For some targets, this implies \s-1GCC\s0 will generate frame -unwind information for all functions, which can produce significant data -size overhead, although it does not affect execution. If you do not -specify this option, \s-1GCC\s0 will enable it by default for languages like -\&\*(C+ which normally require exception handling, and disable it for -languages like C that do not normally require it. However, you may need -to enable this option when compiling C code that needs to interoperate -properly with exception handlers written in \*(C+. You may also wish to -disable this option if you are compiling older \*(C+ programs that don't -use exception handling. -.Ip "\fB\-fnon-call-exceptions\fR" 4 -.IX Item "-fnon-call-exceptions" -Generate code that allows trapping instructions to throw exceptions. -Note that this requires platform-specific runtime support that does -not exist everywhere. Moreover, it only allows \fItrapping\fR -instructions to throw exceptions, i.e. memory references or floating -point instructions. It does not allow exceptions to be thrown from -arbitrary signal handlers such as \f(CW\*(C`SIGALRM\*(C'\fR. -.Ip "\fB\-funwind-tables\fR" 4 -.IX Item "-funwind-tables" -Similar to \fB\-fexceptions\fR, except that it will just generate any needed -static data, but will not affect the generated code in any other way. -You will normally not enable this option; instead, a language processor -that needs this handling would enable it on your behalf. -.Ip "\fB\-fasynchronous-unwind-tables\fR" 4 -.IX Item "-fasynchronous-unwind-tables" -Generate unwind table in dwarf2 format, if supported by target machine. The -table is exact at each instruction boundary, so it can be used for stack -unwinding from asynchronous events (such as debugger or garbage collector). -.Ip "\fB\-fpcc-struct-return\fR" 4 -.IX Item "-fpcc-struct-return" -Return ``short'' \f(CW\*(C`struct\*(C'\fR and \f(CW\*(C`union\*(C'\fR values in memory like -longer ones, rather than in registers. This convention is less -efficient, but it has the advantage of allowing intercallability between -GCC-compiled files and files compiled with other compilers, particularly -the Portable C Compiler (pcc). -.Sp -The precise convention for returning structures in memory depends -on the target configuration macros. -.Sp -Short structures and unions are those whose size and alignment match -that of some integer type. -.Sp -\&\fBWarning:\fR code compiled with the \fB\-fpcc-struct-return\fR -switch is not binary compatible with code compiled with the -\&\fB\-freg-struct-return\fR switch. -Use it to conform to a non-default application binary interface. -.Ip "\fB\-freg-struct-return\fR" 4 -.IX Item "-freg-struct-return" -Return \f(CW\*(C`struct\*(C'\fR and \f(CW\*(C`union\*(C'\fR values in registers when possible. -This is more efficient for small structures than -\&\fB\-fpcc-struct-return\fR. -.Sp -If you specify neither \fB\-fpcc-struct-return\fR nor -\&\fB\-freg-struct-return\fR, \s-1GCC\s0 defaults to whichever convention is -standard for the target. If there is no standard convention, \s-1GCC\s0 -defaults to \fB\-fpcc-struct-return\fR, except on targets where \s-1GCC\s0 is -the principal compiler. In those cases, we can choose the standard, and -we chose the more efficient register return alternative. -.Sp -\&\fBWarning:\fR code compiled with the \fB\-freg-struct-return\fR -switch is not binary compatible with code compiled with the -\&\fB\-fpcc-struct-return\fR switch. -Use it to conform to a non-default application binary interface. -.Ip "\fB\-fshort-enums\fR" 4 -.IX Item "-fshort-enums" -Allocate to an \f(CW\*(C`enum\*(C'\fR type only as many bytes as it needs for the -declared range of possible values. Specifically, the \f(CW\*(C`enum\*(C'\fR type -will be equivalent to the smallest integer type which has enough room. -.Sp -\&\fBWarning:\fR the \fB\-fshort-enums\fR switch causes \s-1GCC\s0 to generate -code that is not binary compatible with code generated without that switch. -Use it to conform to a non-default application binary interface. -.Ip "\fB\-fshort-double\fR" 4 -.IX Item "-fshort-double" -Use the same size for \f(CW\*(C`double\*(C'\fR as for \f(CW\*(C`float\*(C'\fR. -.Sp -\&\fBWarning:\fR the \fB\-fshort-double\fR switch causes \s-1GCC\s0 to generate -code that is not binary compatible with code generated without that switch. -Use it to conform to a non-default application binary interface. -.Ip "\fB\-fshort-wchar\fR" 4 -.IX Item "-fshort-wchar" -Override the underlying type for \fBwchar_t\fR to be \fBshort -unsigned int\fR instead of the default for the target. This option is -useful for building programs to run under \s-1WINE\s0. -.Sp -\&\fBWarning:\fR the \fB\-fshort-wchar\fR switch causes \s-1GCC\s0 to generate -code that is not binary compatible with code generated without that switch. -Use it to conform to a non-default application binary interface. -.Ip "\fB\-fshared-data\fR" 4 -.IX Item "-fshared-data" -Requests that the data and non-\f(CW\*(C`const\*(C'\fR variables of this -compilation be shared data rather than private data. The distinction -makes sense only on certain operating systems, where shared data is -shared between processes running the same program, while private data -exists in one copy per process. -.Ip "\fB\-fno-common\fR" 4 -.IX Item "-fno-common" -In C, allocate even uninitialized global variables in the data section of the -object file, rather than generating them as common blocks. This has the -effect that if the same variable is declared (without \f(CW\*(C`extern\*(C'\fR) in -two different compilations, you will get an error when you link them. -The only reason this might be useful is if you wish to verify that the -program will work on other systems which always work this way. -.Ip "\fB\-fno-ident\fR" 4 -.IX Item "-fno-ident" -Ignore the \fB#ident\fR directive. -.Ip "\fB\-fno-gnu-linker\fR" 4 -.IX Item "-fno-gnu-linker" -Do not output global initializations (such as \*(C+ constructors and -destructors) in the form used by the \s-1GNU\s0 linker (on systems where the \s-1GNU\s0 -linker is the standard method of handling them). Use this option when -you want to use a non-GNU linker, which also requires using the -\&\fBcollect2\fR program to make sure the system linker includes -constructors and destructors. (\fBcollect2\fR is included in the \s-1GCC\s0 -distribution.) For systems which \fImust\fR use \fBcollect2\fR, the -compiler driver \fBgcc\fR is configured to do this automatically. -.Ip "\fB\-finhibit-size-directive\fR" 4 -.IX Item "-finhibit-size-directive" -Don't output a \f(CW\*(C`.size\*(C'\fR assembler directive, or anything else that -would cause trouble if the function is split in the middle, and the -two halves are placed at locations far apart in memory. This option is -used when compiling \fIcrtstuff.c\fR; you should not need to use it -for anything else. -.Ip "\fB\-fverbose-asm\fR" 4 -.IX Item "-fverbose-asm" -Put extra commentary information in the generated assembly code to -make it more readable. This option is generally only of use to those -who actually need to read the generated assembly code (perhaps while -debugging the compiler itself). -.Sp -\&\fB\-fno-verbose-asm\fR, the default, causes the -extra information to be omitted and is useful when comparing two assembler -files. -.Ip "\fB\-fvolatile\fR" 4 -.IX Item "-fvolatile" -Consider all memory references through pointers to be volatile. -.Ip "\fB\-fvolatile-global\fR" 4 -.IX Item "-fvolatile-global" -Consider all memory references to extern and global data items to -be volatile. \s-1GCC\s0 does not consider static data items to be volatile -because of this switch. -.Ip "\fB\-fvolatile-static\fR" 4 -.IX Item "-fvolatile-static" -Consider all memory references to static data to be volatile. -.Ip "\fB\-fpic\fR" 4 -.IX Item "-fpic" -Generate position-independent code (\s-1PIC\s0) suitable for use in a shared -library, if supported for the target machine. Such code accesses all -constant addresses through a global offset table (\s-1GOT\s0). The dynamic -loader resolves the \s-1GOT\s0 entries when the program starts (the dynamic -loader is not part of \s-1GCC\s0; it is part of the operating system). If -the \s-1GOT\s0 size for the linked executable exceeds a machine-specific -maximum size, you get an error message from the linker indicating that -\&\fB\-fpic\fR does not work; in that case, recompile with \fB\-fPIC\fR -instead. (These maximums are 16k on the m88k, 8k on the Sparc, and 32k -on the m68k and \s-1RS/6000\s0. The 386 has no such limit.) -.Sp -Position-independent code requires special support, and therefore works -only on certain machines. For the 386, \s-1GCC\s0 supports \s-1PIC\s0 for System V -but not for the Sun 386i. Code generated for the \s-1IBM\s0 \s-1RS/6000\s0 is always -position-independent. -.Ip "\fB\-fPIC\fR" 4 -.IX Item "-fPIC" -If supported for the target machine, emit position-independent code, -suitable for dynamic linking and avoiding any limit on the size of the -global offset table. This option makes a difference on the m68k, m88k, -and the Sparc. -.Sp -Position-independent code requires special support, and therefore works -only on certain machines. -.Ip "\fB\-ffixed-\fR\fIreg\fR" 4 -.IX Item "-ffixed-reg" -Treat the register named \fIreg\fR as a fixed register; generated code -should never refer to it (except perhaps as a stack pointer, frame -pointer or in some other fixed role). -.Sp -\&\fIreg\fR must be the name of a register. The register names accepted -are machine-specific and are defined in the \f(CW\*(C`REGISTER_NAMES\*(C'\fR -macro in the machine description macro file. -.Sp -This flag does not have a negative form, because it specifies a -three-way choice. -.Ip "\fB\-fcall-used-\fR\fIreg\fR" 4 -.IX Item "-fcall-used-reg" -Treat the register named \fIreg\fR as an allocable register that is -clobbered by function calls. It may be allocated for temporaries or -variables that do not live across a call. Functions compiled this way -will not save and restore the register \fIreg\fR. -.Sp -It is an error to used this flag with the frame pointer or stack pointer. -Use of this flag for other registers that have fixed pervasive roles in -the machine's execution model will produce disastrous results. -.Sp -This flag does not have a negative form, because it specifies a -three-way choice. -.Ip "\fB\-fcall-saved-\fR\fIreg\fR" 4 -.IX Item "-fcall-saved-reg" -Treat the register named \fIreg\fR as an allocable register saved by -functions. It may be allocated even for temporaries or variables that -live across a call. Functions compiled this way will save and restore -the register \fIreg\fR if they use it. -.Sp -It is an error to used this flag with the frame pointer or stack pointer. -Use of this flag for other registers that have fixed pervasive roles in -the machine's execution model will produce disastrous results. -.Sp -A different sort of disaster will result from the use of this flag for -a register in which function values may be returned. -.Sp -This flag does not have a negative form, because it specifies a -three-way choice. -.Ip "\fB\-fpack-struct\fR" 4 -.IX Item "-fpack-struct" -Pack all structure members together without holes. -.Sp -\&\fBWarning:\fR the \fB\-fpack-struct\fR switch causes \s-1GCC\s0 to generate -code that is not binary compatible with code generated without that switch. -Additionally, it makes the code suboptimial. -Use it to conform to a non-default application binary interface. -.Ip "\fB\-finstrument-functions\fR" 4 -.IX Item "-finstrument-functions" -Generate instrumentation calls for entry and exit to functions. Just -after function entry and just before function exit, the following -profiling functions will be called with the address of the current -function and its call site. (On some platforms, -\&\f(CW\*(C`_\|_builtin_return_address\*(C'\fR does not work beyond the current -function, so the call site information may not be available to the -profiling functions otherwise.) -.Sp -.Vb 4 -\& void __cyg_profile_func_enter (void *this_fn, -\& void *call_site); -\& void __cyg_profile_func_exit (void *this_fn, -\& void *call_site); -.Ve -The first argument is the address of the start of the current function, -which may be looked up exactly in the symbol table. -.Sp -This instrumentation is also done for functions expanded inline in other -functions. The profiling calls will indicate where, conceptually, the -inline function is entered and exited. This means that addressable -versions of such functions must be available. If all your uses of a -function are expanded inline, this may mean an additional expansion of -code size. If you use \fBextern inline\fR in your C code, an -addressable version of such functions must be provided. (This is -normally the case anyways, but if you get lucky and the optimizer always -expands the functions inline, you might have gotten away without -providing static copies.) -.Sp -A function may be given the attribute \f(CW\*(C`no_instrument_function\*(C'\fR, in -which case this instrumentation will not be done. This can be used, for -example, for the profiling functions listed above, high-priority -interrupt routines, and any functions from which the profiling functions -cannot safely be called (perhaps signal handlers, if the profiling -routines generate output or allocate memory). -.Ip "\fB\-fstack-check\fR" 4 -.IX Item "-fstack-check" -Generate code to verify that you do not go beyond the boundary of the -stack. You should specify this flag if you are running in an -environment with multiple threads, but only rarely need to specify it in -a single-threaded environment since stack overflow is automatically -detected on nearly all systems if there is only one stack. -.Sp -Note that this switch does not actually cause checking to be done; the -operating system must do that. The switch causes generation of code -to ensure that the operating system sees the stack being extended. -.Ip "\fB\-fstack-limit-register=\fR\fIreg\fR" 4 -.IX Item "-fstack-limit-register=reg" -.PD 0 -.Ip "\fB\-fstack-limit-symbol=\fR\fIsym\fR" 4 -.IX Item "-fstack-limit-symbol=sym" -.Ip "\fB\-fno-stack-limit\fR" 4 -.IX Item "-fno-stack-limit" -.PD -Generate code to ensure that the stack does not grow beyond a certain value, -either the value of a register or the address of a symbol. If the stack -would grow beyond the value, a signal is raised. For most targets, -the signal is raised before the stack overruns the boundary, so -it is possible to catch the signal without taking special precautions. -.Sp -For instance, if the stack starts at absolute address \fB0x80000000\fR -and grows downwards, you can use the flags -\&\fB\-fstack-limit-symbol=_\|_stack_limit\fR and -\&\fB\-Wl,\-\-defsym,_\|_stack_limit=0x7ffe0000\fR to enforce a stack limit -of 128KB. Note that this may only work with the \s-1GNU\s0 linker. -.Ip "\fB\-fargument-alias\fR" 4 -.IX Item "-fargument-alias" -.PD 0 -.Ip "\fB\-fargument-noalias\fR" 4 -.IX Item "-fargument-noalias" -.Ip "\fB\-fargument-noalias-global\fR" 4 -.IX Item "-fargument-noalias-global" -.PD -Specify the possible relationships among parameters and between -parameters and global data. -.Sp -\&\fB\-fargument-alias\fR specifies that arguments (parameters) may -alias each other and may alias global storage.\fB\-fargument-noalias\fR specifies that arguments do not alias -each other, but may alias global storage.\fB\-fargument-noalias-global\fR specifies that arguments do not -alias each other and do not alias global storage. -.Sp -Each language will automatically use whatever option is required by -the language standard. You should not need to use these options yourself. -.Ip "\fB\-fleading-underscore\fR" 4 -.IX Item "-fleading-underscore" -This option and its counterpart, \fB\-fno-leading-underscore\fR, forcibly -change the way C symbols are represented in the object file. One use -is to help link with legacy assembly code. -.Sp -\&\fBWarning:\fR the \fB\-fleading-underscore\fR switch causes \s-1GCC\s0 to -generate code that is not binary compatible with code generated without that -switch. Use it to conform to a non-default application binary interface. -Not all targets provide complete support for this switch. -.SH "ENVIRONMENT" -.IX Header "ENVIRONMENT" -This section describes several environment variables that affect how \s-1GCC\s0 -operates. Some of them work by specifying directories or prefixes to use -when searching for various kinds of files. Some are used to specify other -aspects of the compilation environment. -.PP -Note that you can also specify places to search using options such as -\&\fB\-B\fR, \fB\-I\fR and \fB\-L\fR. These -take precedence over places specified using environment variables, which -in turn take precedence over those specified by the configuration of \s-1GCC\s0. -.Ip "\fB\s-1LANG\s0\fR" 4 -.IX Item "LANG" -.PD 0 -.Ip "\fB\s-1LC_CTYPE\s0\fR" 4 -.IX Item "LC_CTYPE" -.Ip "\fB\s-1LC_MESSAGES\s0\fR" 4 -.IX Item "LC_MESSAGES" -.Ip "\fB\s-1LC_ALL\s0\fR" 4 -.IX Item "LC_ALL" -.PD -These environment variables control the way that \s-1GCC\s0 uses -localization information that allow \s-1GCC\s0 to work with different -national conventions. \s-1GCC\s0 inspects the locale categories -\&\fB\s-1LC_CTYPE\s0\fR and \fB\s-1LC_MESSAGES\s0\fR if it has been configured to do -so. These locale categories can be set to any value supported by your -installation. A typical value is \fBen_UK\fR for English in the United -Kingdom. -.Sp -The \fB\s-1LC_CTYPE\s0\fR environment variable specifies character -classification. \s-1GCC\s0 uses it to determine the character boundaries in -a string; this is needed for some multibyte encodings that contain quote -and escape characters that would otherwise be interpreted as a string -end or escape. -.Sp -The \fB\s-1LC_MESSAGES\s0\fR environment variable specifies the language to -use in diagnostic messages. -.Sp -If the \fB\s-1LC_ALL\s0\fR environment variable is set, it overrides the value -of \fB\s-1LC_CTYPE\s0\fR and \fB\s-1LC_MESSAGES\s0\fR; otherwise, \fB\s-1LC_CTYPE\s0\fR -and \fB\s-1LC_MESSAGES\s0\fR default to the value of the \fB\s-1LANG\s0\fR -environment variable. If none of these variables are set, \s-1GCC\s0 -defaults to traditional C English behavior. -.Ip "\fB\s-1TMPDIR\s0\fR" 4 -.IX Item "TMPDIR" -If \fB\s-1TMPDIR\s0\fR is set, it specifies the directory to use for temporary -files. \s-1GCC\s0 uses temporary files to hold the output of one stage of -compilation which is to be used as input to the next stage: for example, -the output of the preprocessor, which is the input to the compiler -proper. -.Ip "\fB\s-1GCC_EXEC_PREFIX\s0\fR" 4 -.IX Item "GCC_EXEC_PREFIX" -If \fB\s-1GCC_EXEC_PREFIX\s0\fR is set, it specifies a prefix to use in the -names of the subprograms executed by the compiler. No slash is added -when this prefix is combined with the name of a subprogram, but you can -specify a prefix that ends with a slash if you wish. -.Sp -If \fB\s-1GCC_EXEC_PREFIX\s0\fR is not set, \s-1GCC\s0 will attempt to figure out -an appropriate prefix to use based on the pathname it was invoked with. -.Sp -If \s-1GCC\s0 cannot find the subprogram using the specified prefix, it -tries looking in the usual places for the subprogram. -.Sp -The default value of \fB\s-1GCC_EXEC_PREFIX\s0\fR is -\&\fI\fIprefix\fI/lib/gcc-lib/\fR where \fIprefix\fR is the value -of \f(CW\*(C`prefix\*(C'\fR when you ran the \fIconfigure\fR script. -.Sp -Other prefixes specified with \fB\-B\fR take precedence over this prefix. -.Sp -This prefix is also used for finding files such as \fIcrt0.o\fR that are -used for linking. -.Sp -In addition, the prefix is used in an unusual way in finding the -directories to search for header files. For each of the standard -directories whose name normally begins with \fB/usr/local/lib/gcc-lib\fR -(more precisely, with the value of \fB\s-1GCC_INCLUDE_DIR\s0\fR), \s-1GCC\s0 tries -replacing that beginning with the specified prefix to produce an -alternate directory name. Thus, with \fB\-Bfoo/\fR, \s-1GCC\s0 will search -\&\fIfoo/bar\fR where it would normally search \fI/usr/local/lib/bar\fR. -These alternate directories are searched first; the standard directories -come next. -.Ip "\fB\s-1COMPILER_PATH\s0\fR" 4 -.IX Item "COMPILER_PATH" -The value of \fB\s-1COMPILER_PATH\s0\fR is a colon-separated list of -directories, much like \fB\s-1PATH\s0\fR. \s-1GCC\s0 tries the directories thus -specified when searching for subprograms, if it can't find the -subprograms using \fB\s-1GCC_EXEC_PREFIX\s0\fR. -.Ip "\fB\s-1LIBRARY_PATH\s0\fR" 4 -.IX Item "LIBRARY_PATH" -The value of \fB\s-1LIBRARY_PATH\s0\fR is a colon-separated list of -directories, much like \fB\s-1PATH\s0\fR. When configured as a native compiler, -\&\s-1GCC\s0 tries the directories thus specified when searching for special -linker files, if it can't find them using \fB\s-1GCC_EXEC_PREFIX\s0\fR. Linking -using \s-1GCC\s0 also uses these directories when searching for ordinary -libraries for the \fB\-l\fR option (but directories specified with -\&\fB\-L\fR come first). -.Ip "\fB\s-1LANG\s0\fR" 4 -.IX Item "LANG" -This variable is used to pass locale information to the compiler. One way in -which this information is used is to determine the character set to be used -when character literals, string literals and comments are parsed in C and \*(C+. -When the compiler is configured to allow multibyte characters, -the following values for \fB\s-1LANG\s0\fR are recognized: -.RS 4 -.Ip "\fBC-JIS\fR" 4 -.IX Item "C-JIS" -Recognize \s-1JIS\s0 characters. -.Ip "\fBC-SJIS\fR" 4 -.IX Item "C-SJIS" -Recognize \s-1SJIS\s0 characters. -.Ip "\fBC-EUCJP\fR" 4 -.IX Item "C-EUCJP" -Recognize \s-1EUCJP\s0 characters. -.RE -.RS 4 -.Sp -If \fB\s-1LANG\s0\fR is not defined, or if it has some other value, then the -compiler will use mblen and mbtowc as defined by the default locale to -recognize and translate multibyte characters. -.RE -.PP -Some additional environments variables affect the behavior of the -preprocessor. -.Ip "\fB\s-1CPATH\s0\fR" 4 -.IX Item "CPATH" -.PD 0 -.Ip "\fBC_INCLUDE_PATH\fR" 4 -.IX Item "C_INCLUDE_PATH" -.Ip "\fB\s-1CPLUS_INCLUDE_PATH\s0\fR" 4 -.IX Item "CPLUS_INCLUDE_PATH" -.Ip "\fB\s-1OBJC_INCLUDE_PATH\s0\fR" 4 -.IX Item "OBJC_INCLUDE_PATH" -.PD -Each variable's value is a list of directories separated by a special -character, much like \fB\s-1PATH\s0\fR, in which to look for header files. -The special character, \f(CW\*(C`PATH_SEPARATOR\*(C'\fR, is target-dependent and -determined at \s-1GCC\s0 build time. For Windows-based targets it is a -semicolon, and for almost all other targets it is a colon. -.Sp -\&\fB\s-1CPATH\s0\fR specifies a list of directories to be searched as if -specified with \fB\-I\fR, but after any paths given with \fB\-I\fR -options on the command line. The environment variable is used -regardless of which language is being preprocessed. -.Sp -The remaining environment variables apply only when preprocessing the -particular language indicated. Each specifies a list of directories -to be searched as if specified with \fB\-isystem\fR, but after any -paths given with \fB\-isystem\fR options on the command line. -.Ip "\fB\s-1DEPENDENCIES_OUTPUT\s0\fR" 4 -.IX Item "DEPENDENCIES_OUTPUT" -@anchor{\s-1DEPENDENCIES_OUTPUT\s0} -If this variable is set, its value specifies how to output -dependencies for Make based on the non-system header files processed -by the compiler. System header files are ignored in the dependency -output. -.Sp -The value of \fB\s-1DEPENDENCIES_OUTPUT\s0\fR can be just a file name, in -which case the Make rules are written to that file, guessing the target -name from the source file name. Or the value can have the form -\&\fIfile\fR\fB \fR\fItarget\fR, in which case the rules are written to -file \fIfile\fR using \fItarget\fR as the target name. -.Sp -In other words, this environment variable is equivalent to combining -the options \fB\-MM\fR and \fB\-MF\fR, -with an optional \fB\-MT\fR switch too. -.Ip "\fB\s-1SUNPRO_DEPENDENCIES\s0\fR" 4 -.IX Item "SUNPRO_DEPENDENCIES" -This variable is the same as the environment variable -\&\fB\s-1DEPENDENCIES_OUTPUT\s0\fR, except that -system header files are not ignored, so it implies \fB\-M\fR rather -than \fB\-MM\fR. However, the dependence on the main input file is -omitted. -.SH "BUGS" -.IX Header "BUGS" -For instructions on reporting bugs, see -<\fBhttp://gcc.gnu.org/bugs.html\fR>. Use of the \fBgccbug\fR -script to report bugs is recommended. -.SH "FOOTNOTES" -.IX Header "FOOTNOTES" -.Ip "1." 4 -On some systems, \fBgcc \-shared\fR -needs to build supplementary stub code for constructors to work. On -multi-libbed systems, \fBgcc \-shared\fR must select the correct support -libraries to link against. Failing to supply the correct flags may lead -to subtle defects. Supplying them in cases where they are not necessary -is innocuous. -.SH "SEE ALSO" -.IX Header "SEE ALSO" -\&\fIgpl\fR\|(7), \fIgfdl\fR\|(7), \fIfsf-funding\fR\|(7), -\&\fIcpp\fR\|(1), \fIgcov\fR\|(1), \fIg77\fR\|(1), \fIas\fR\|(1), \fIld\fR\|(1), \fIgdb\fR\|(1), \fIadb\fR\|(1), \fIdbx\fR\|(1), \fIsdb\fR\|(1) -and the Info entries for \fIgcc\fR, \fIcpp\fR, \fIg77\fR, \fIas\fR, -\&\fIld\fR, \fIbinutils\fR and \fIgdb\fR. -.SH "AUTHOR" -.IX Header "AUTHOR" -See the Info entry for \fBgcc\fR, or -<\fBhttp://gcc.gnu.org/onlinedocs/gcc/Contributors.html\fR>, -for contributors to \s-1GCC\s0. -.SH "COPYRIGHT" -.IX Header "COPYRIGHT" -Copyright (c) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, -1998, 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc. -.PP -Permission is granted to copy, distribute and/or modify this document -under the terms of the \s-1GNU\s0 Free Documentation License, Version 1.1 or -any later version published by the Free Software Foundation; with the -Invariant Sections being ``\s-1GNU\s0 General Public License'' and ``Funding -Free Software'', the Front-Cover texts being (a) (see below), and with -the Back-Cover Texts being (b) (see below). A copy of the license is -included in the \fIgfdl\fR\|(7) man page. -.PP -(a) The \s-1FSF\s0's Front-Cover Text is: -.PP -.Vb 1 -\& A GNU Manual -.Ve -(b) The \s-1FSF\s0's Back-Cover Text is: -.PP -.Vb 3 -\& You have freedom to copy and modify this GNU Manual, like GNU -\& software. Copies published by the Free Software Foundation raise -\& funds for GNU development. -.Ve diff --git a/contrib/gcc/doc/gcov.1 b/contrib/gcc/doc/gcov.1 deleted file mode 100644 index 44d1e33c8b74..000000000000 --- a/contrib/gcc/doc/gcov.1 +++ /dev/null @@ -1,453 +0,0 @@ -.\" Automatically generated by Pod::Man version 1.15 -.\" Wed Feb 5 03:13:55 2003 -.\" -.\" Standard preamble: -.\" ====================================================================== -.de Sh \" Subsection heading -.br -.if t .Sp -.ne 5 -.PP -\fB\\$1\fR -.PP -.. -.de Sp \" Vertical space (when we can't use .PP) -.if t .sp .5v -.if n .sp -.. -.de Ip \" List item -.br -.ie \\n(.$>=3 .ne \\$3 -.el .ne 3 -.IP "\\$1" \\$2 -.. -.de Vb \" Begin verbatim text -.ft CW -.nf -.ne \\$1 -.. -.de Ve \" End verbatim text -.ft R - -.fi -.. -.\" Set up some character translations and predefined strings. \*(-- will -.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left -.\" double quote, and \*(R" will give a right double quote. | will give a -.\" real vertical bar. \*(C+ will give a nicer C++. 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Use it in concert with \s-1GCC\s0 -to analyze your programs to help create more efficient, faster -running code. You can use \fBgcov\fR as a profiling tool to help -discover where your optimization efforts will best affect your code. You -can also use \fBgcov\fR along with the other profiling tool, -\&\fBgprof\fR, to assess which parts of your code use the greatest amount -of computing time. -.PP -Profiling tools help you analyze your code's performance. Using a -profiler such as \fBgcov\fR or \fBgprof\fR, you can find out some -basic performance statistics, such as: -.Ip "\(bu" 4 -how often each line of code executes -.Ip "\(bu" 4 -what lines of code are actually executed -.Ip "\(bu" 4 -how much computing time each section of code uses -.PP -Once you know these things about how your code works when compiled, you -can look at each module to see which modules should be optimized. -\&\fBgcov\fR helps you determine where to work on optimization. -.PP -Software developers also use coverage testing in concert with -testsuites, to make sure software is actually good enough for a release. -Testsuites can verify that a program works as expected; a coverage -program tests to see how much of the program is exercised by the -testsuite. Developers can then determine what kinds of test cases need -to be added to the testsuites to create both better testing and a better -final product. -.PP -You should compile your code without optimization if you plan to use -\&\fBgcov\fR because the optimization, by combining some lines of code -into one function, may not give you as much information as you need to -look for `hot spots' where the code is using a great deal of computer -time. Likewise, because \fBgcov\fR accumulates statistics by line (at -the lowest resolution), it works best with a programming style that -places only one statement on each line. If you use complicated macros -that expand to loops or to other control structures, the statistics are -less helpful\-\-\-they only report on the line where the macro call -appears. If your complex macros behave like functions, you can replace -them with inline functions to solve this problem. -.PP -\&\fBgcov\fR creates a logfile called \fI\fIsourcefile\fI.gcov\fR which -indicates how many times each line of a source file \fI\fIsourcefile\fI.c\fR -has executed. You can use these logfiles along with \fBgprof\fR to aid -in fine-tuning the performance of your programs. \fBgprof\fR gives -timing information you can use along with the information you get from -\&\fBgcov\fR. -.PP -\&\fBgcov\fR works only on code compiled with \s-1GCC\s0. It is not -compatible with any other profiling or test coverage mechanism. -.SH "OPTIONS" -.IX Header "OPTIONS" -.Ip "\fB\-h\fR" 4 -.IX Item "-h" -.PD 0 -.Ip "\fB\*(--help\fR" 4 -.IX Item "help" -.PD -Display help about using \fBgcov\fR (on the standard output), and -exit without doing any further processing. -.Ip "\fB\-v\fR" 4 -.IX Item "-v" -.PD 0 -.Ip "\fB\*(--version\fR" 4 -.IX Item "version" -.PD -Display the \fBgcov\fR version number (on the standard output), -and exit without doing any further processing. -.Ip "\fB\-b\fR" 4 -.IX Item "-b" -.PD 0 -.Ip "\fB\*(--branch-probabilities\fR" 4 -.IX Item "branch-probabilities" -.PD -Write branch frequencies to the output file, and write branch summary -info to the standard output. This option allows you to see how often -each branch in your program was taken. -.Ip "\fB\-c\fR" 4 -.IX Item "-c" -.PD 0 -.Ip "\fB\*(--branch-counts\fR" 4 -.IX Item "branch-counts" -.PD -Write branch frequencies as the number of branches taken, rather than -the percentage of branches taken. -.Ip "\fB\-n\fR" 4 -.IX Item "-n" -.PD 0 -.Ip "\fB\*(--no-output\fR" 4 -.IX Item "no-output" -.PD -Do not create the \fBgcov\fR output file. -.Ip "\fB\-l\fR" 4 -.IX Item "-l" -.PD 0 -.Ip "\fB\*(--long-file-names\fR" 4 -.IX Item "long-file-names" -.PD -Create long file names for included source files. For example, if the -header file \fIx.h\fR contains code, and was included in the file -\&\fIa.c\fR, then running \fBgcov\fR on the file \fIa.c\fR will produce -an output file called \fIa.c.x.h.gcov\fR instead of \fIx.h.gcov\fR. -This can be useful if \fIx.h\fR is included in multiple source files. -.Ip "\fB\-f\fR" 4 -.IX Item "-f" -.PD 0 -.Ip "\fB\*(--function-summaries\fR" 4 -.IX Item "function-summaries" -.PD -Output summaries for each function in addition to the file level summary. -.Ip "\fB\-o\fR \fIdirectory\fR" 4 -.IX Item "-o directory" -.PD 0 -.Ip "\fB\*(--object-directory\fR \fIdirectory\fR" 4 -.IX Item "object-directory directory" -.PD -The directory where the object files live. Gcov will search for \fI.bb\fR, -\&\fI.bbg\fR, and \fI.da\fR files in this directory. -.PP -When using \fBgcov\fR, you must first compile your program with two -special \s-1GCC\s0 options: \fB\-fprofile-arcs \-ftest-coverage\fR. -This tells the compiler to generate additional information needed by -gcov (basically a flow graph of the program) and also includes -additional code in the object files for generating the extra profiling -information needed by gcov. These additional files are placed in the -directory where the source code is located. -.PP -Running the program will cause profile output to be generated. For each -source file compiled with \fB\-fprofile-arcs\fR, an accompanying \fI.da\fR -file will be placed in the source directory. -.PP -Running \fBgcov\fR with your program's source file names as arguments -will now produce a listing of the code along with frequency of execution -for each line. For example, if your program is called \fItmp.c\fR, this -is what you see when you use the basic \fBgcov\fR facility: -.PP -.Vb 5 -\& $ gcc -fprofile-arcs -ftest-coverage tmp.c -\& $ a.out -\& $ gcov tmp.c -\& 87.50% of 8 source lines executed in file tmp.c -\& Creating tmp.c.gcov. -.Ve -The file \fItmp.c.gcov\fR contains output from \fBgcov\fR. -Here is a sample: -.PP -.Vb 3 -\& main() -\& { -\& 1 int i, total; -.Ve -.Vb 1 -\& 1 total = 0; -.Ve -.Vb 2 -\& 11 for (i = 0; i < 10; i++) -\& 10 total += i; -.Ve -.Vb 5 -\& 1 if (total != 45) -\& ###### printf ("Failure\en"); -\& else -\& 1 printf ("Success\en"); -\& 1 } -.Ve -When you use the \fB\-b\fR option, your output looks like this: -.PP -.Vb 6 -\& $ gcov -b tmp.c -\& 87.50% of 8 source lines executed in file tmp.c -\& 80.00% of 5 branches executed in file tmp.c -\& 80.00% of 5 branches taken at least once in file tmp.c -\& 50.00% of 2 calls executed in file tmp.c -\& Creating tmp.c.gcov. -.Ve -Here is a sample of a resulting \fItmp.c.gcov\fR file: -.PP -.Vb 3 -\& main() -\& { -\& 1 int i, total; -.Ve -.Vb 1 -\& 1 total = 0; -.Ve -.Vb 5 -\& 11 for (i = 0; i < 10; i++) -\& branch 0 taken = 91% -\& branch 1 taken = 100% -\& branch 2 taken = 100% -\& 10 total += i; -.Ve -.Vb 9 -\& 1 if (total != 45) -\& branch 0 taken = 100% -\& ###### printf ("Failure\en"); -\& call 0 never executed -\& branch 1 never executed -\& else -\& 1 printf ("Success\en"); -\& call 0 returns = 100% -\& 1 } -.Ve -For each basic block, a line is printed after the last line of the basic -block describing the branch or call that ends the basic block. There can -be multiple branches and calls listed for a single source line if there -are multiple basic blocks that end on that line. In this case, the -branches and calls are each given a number. There is no simple way to map -these branches and calls back to source constructs. In general, though, -the lowest numbered branch or call will correspond to the leftmost construct -on the source line. -.PP -For a branch, if it was executed at least once, then a percentage -indicating the number of times the branch was taken divided by the -number of times the branch was executed will be printed. Otherwise, the -message ``never executed'' is printed. -.PP -For a call, if it was executed at least once, then a percentage -indicating the number of times the call returned divided by the number -of times the call was executed will be printed. This will usually be -100%, but may be less for functions call \f(CW\*(C`exit\*(C'\fR or \f(CW\*(C`longjmp\*(C'\fR, -and thus may not return every time they are called. -.PP -The execution counts are cumulative. If the example program were -executed again without removing the \fI.da\fR file, the count for the -number of times each line in the source was executed would be added to -the results of the previous \fIrun\fR\|(s). This is potentially useful in -several ways. For example, it could be used to accumulate data over a -number of program runs as part of a test verification suite, or to -provide more accurate long-term information over a large number of -program runs. -.PP -The data in the \fI.da\fR files is saved immediately before the program -exits. For each source file compiled with \fB\-fprofile-arcs\fR, the profiling -code first attempts to read in an existing \fI.da\fR file; if the file -doesn't match the executable (differing number of basic block counts) it -will ignore the contents of the file. It then adds in the new execution -counts and finally writes the data to the file. -.Sh "Using \fBgcov\fP with \s-1GCC\s0 Optimization" -.IX Subsection "Using gcov with GCC Optimization" -If you plan to use \fBgcov\fR to help optimize your code, you must -first compile your program with two special \s-1GCC\s0 options: -\&\fB\-fprofile-arcs \-ftest-coverage\fR. Aside from that, you can use any -other \s-1GCC\s0 options; but if you want to prove that every single line -in your program was executed, you should not compile with optimization -at the same time. On some machines the optimizer can eliminate some -simple code lines by combining them with other lines. For example, code -like this: -.PP -.Vb 4 -\& if (a != b) -\& c = 1; -\& else -\& c = 0; -.Ve -can be compiled into one instruction on some machines. In this case, -there is no way for \fBgcov\fR to calculate separate execution counts -for each line because there isn't separate code for each line. Hence -the \fBgcov\fR output looks like this if you compiled the program with -optimization: -.PP -.Vb 4 -\& 100 if (a != b) -\& 100 c = 1; -\& 100 else -\& 100 c = 0; -.Ve -The output shows that this block of code, combined by optimization, -executed 100 times. In one sense this result is correct, because there -was only one instruction representing all four of these lines. However, -the output does not indicate how many times the result was 0 and how -many times the result was 1. -.SH "SEE ALSO" -.IX Header "SEE ALSO" -\&\fIgpl\fR\|(7), \fIgfdl\fR\|(7), \fIfsf-funding\fR\|(7), \fIgcc\fR\|(1) and the Info entry for \fIgcc\fR. -.SH "COPYRIGHT" -.IX Header "COPYRIGHT" -Copyright (c) 1996, 1997, 1999, 2000, 2001 Free Software Foundation, Inc. -.PP -Permission is granted to copy, distribute and/or modify this document -under the terms of the \s-1GNU\s0 Free Documentation License, Version 1.1 or -any later version published by the Free Software Foundation; with the -Invariant Sections being ``\s-1GNU\s0 General Public License'' and ``Funding -Free Software'', the Front-Cover texts being (a) (see below), and with -the Back-Cover Texts being (b) (see below). A copy of the license is -included in the \fIgfdl\fR\|(7) man page. -.PP -(a) The \s-1FSF\s0's Front-Cover Text is: -.PP -.Vb 1 -\& A GNU Manual -.Ve -(b) The \s-1FSF\s0's Back-Cover Text is: -.PP -.Vb 3 -\& You have freedom to copy and modify this GNU Manual, like GNU -\& software. Copies published by the Free Software Foundation raise -\& funds for GNU development. -.Ve diff --git a/contrib/gcc/f/BUGS b/contrib/gcc/f/BUGS deleted file mode 100644 index acfe4abf4b93..000000000000 --- a/contrib/gcc/f/BUGS +++ /dev/null @@ -1,130 +0,0 @@ -_Note:_ This file is automatically generated from the files -`bugs0.texi' and `bugs.texi'. `BUGS' is _not_ a source file, although -it is normally included within source distributions. - - This file lists known bugs in the GCC-3.2 version of the GNU Fortran -compiler. Copyright (C) 1995,1996,1997,1998,1999,2000,2001,2002 Free -Software Foundation, Inc. You may copy, distribute, and modify it -freely as long as you preserve this copyright notice and permission -notice. - -Known Bugs In GNU Fortran -************************* - - This section identifies bugs that `g77' _users_ might run into in -the GCC-3.2 version of `g77'. This includes bugs that are actually in -the `gcc' back end (GBE) or in `libf2c', because those sets of code are -at least somewhat under the control of (and necessarily intertwined -with) `g77', so it isn't worth separating them out. - - For information on bugs in _other_ versions of `g77', see -`gcc/gcc/f/NEWS'. There, lists of bugs fixed in various versions of -`g77' can help determine what bugs existed in prior versions. - - An online, "live" version of this document (derived directly from -the mainline, development version of `g77' within `gcc') is available -via `http://www.gnu.org/software/gcc/onlinedocs/g77/Trouble.html'. -Follow the "Known Bugs" link. - - The following information was last updated on 2002-02-01: - - * `g77' fails to warn about use of a "live" iterative-DO variable as - an implied-DO variable in a `WRITE' or `PRINT' statement (although - it does warn about this in a `READ' statement). - - * Something about `g77''s straightforward handling of label - references and definitions sometimes prevents the GBE from - unrolling loops. Until this is solved, try inserting or removing - `CONTINUE' statements as the terminal statement, using the `END DO' - form instead, and so on. - - * Some confusion in diagnostics concerning failing `INCLUDE' - statements from within `INCLUDE''d or `#include''d files. - - * `g77' assumes that `INTEGER(KIND=1)' constants range from `-2**31' - to `2**31-1' (the range for two's-complement 32-bit values), - instead of determining their range from the actual range of the - type for the configuration (and, someday, for the constant). - - Further, it generally doesn't implement the handling of constants - very well in that it makes assumptions about the configuration - that it no longer makes regarding variables (types). - - Included with this item is the fact that `g77' doesn't recognize - that, on IEEE-754/854-compliant systems, `0./0.' should produce a - NaN and no warning instead of the value `0.' and a warning. - - * `g77' uses way too much memory and CPU time to process large - aggregate areas having any initialized elements. - - For example, `REAL A(1000000)' followed by `DATA A(1)/1/' takes up - way too much time and space, including the size of the generated - assembler file. - - Version 0.5.18 improves cases like this--specifically, cases of - _sparse_ initialization that leave large, contiguous areas - uninitialized--significantly. However, even with the - improvements, these cases still require too much memory and CPU - time. - - (Version 0.5.18 also improves cases where the initial values are - zero to a much greater degree, so if the above example ends with - `DATA A(1)/0/', the compile-time performance will be about as good - as it will ever get, aside from unrelated improvements to the - compiler.) - - Note that `g77' does display a warning message to notify the user - before the compiler appears to hang. - - * When debugging, after starting up the debugger but before being - able to see the source code for the main program unit, the user - must currently set a breakpoint at `MAIN__' (or `MAIN___' or - `MAIN_' if `MAIN__' doesn't exist) and run the program until it - hits the breakpoint. At that point, the main program unit is - activated and about to execute its first executable statement, but - that's the state in which the debugger should start up, as is the - case for languages like C. - - * Debugging `g77'-compiled code using debuggers other than `gdb' is - likely not to work. - - Getting `g77' and `gdb' to work together is a known - problem--getting `g77' to work properly with other debuggers, for - which source code often is unavailable to `g77' developers, seems - like a much larger, unknown problem, and is a lower priority than - making `g77' and `gdb' work together properly. - - On the other hand, information about problems other debuggers have - with `g77' output might make it easier to properly fix `g77', and - perhaps even improve `gdb', so it is definitely welcome. Such - information might even lead to all relevant products working - together properly sooner. - - * `g77' doesn't work perfectly on 64-bit configurations such as the - Digital Semiconductor ("DEC") Alpha. - - This problem is largely resolved as of version 0.5.23. - - * `g77' currently inserts needless padding for things like `COMMON - A,IPAD' where `A' is `CHARACTER*1' and `IPAD' is `INTEGER(KIND=1)' - on machines like x86, because the back end insists that `IPAD' be - aligned to a 4-byte boundary, but the processor has no such - requirement (though it is usually good for performance). - - The `gcc' back end needs to provide a wider array of - specifications of alignment requirements and preferences for - targets, and front ends like `g77' should take advantage of this - when it becomes available. - - * The `libf2c' routines that perform some run-time arithmetic on - `COMPLEX' operands were modified circa version 0.5.20 of `g77' to - work properly even in the presence of aliased operands. - - While the `g77' and `netlib' versions of `libf2c' differ on how - this is accomplished, the main differences are that we believe the - `g77' version works properly even in the presence of _partially_ - aliased operands. - - However, these modifications have reduced performance on targets - such as x86, due to the extra copies of operands involved. - diff --git a/contrib/gcc/f/NEWS b/contrib/gcc/f/NEWS deleted file mode 100644 index cc73668ebd7a..000000000000 --- a/contrib/gcc/f/NEWS +++ /dev/null @@ -1,531 +0,0 @@ -_Note:_ This file is automatically generated from the files -`news0.texi' and `news.texi'. `NEWS' is _not_ a source file, although -it is normally included within source distributions. - - This file lists news about the GCC-3.2 version (and some other -versions) of the GNU Fortran compiler. Copyright (C) -1995,1996,1997,1998,1999,2000,2001,2002 Free Software Foundation, Inc. -You may copy, distribute, and modify it freely as long as you preserve -this copyright notice and permission notice. - -News About GNU Fortran -********************** - - Changes made to recent versions of GNU Fortran are listed below, -with the most recent version first. - - The changes are generally listed in order: - - 1. Code-generation and run-time-library bug-fixes - - 2. Compiler and run-time-library crashes involving valid code that - have been fixed - - 3. New features - - 4. Fixes and enhancements to existing features - - 5. New diagnostics - - 6. Internal improvements - - 7. Miscellany - - This order is not strict--for example, some items involve a -combination of these elements. - - Note that two variants of `g77' are tracked below. The `egcs' -variant is described vis-a-vis previous versions of `egcs' and/or an -official FSF version, as appropriate. Note that all such variants are -obsolete _as of July 1999_ - the information is retained here only for -its historical value. - - Therefore, `egcs' versions sometimes have multiple listings to help -clarify how they differ from other versions, though this can make -getting a complete picture of what a particular `egcs' version contains -somewhat more difficult. - - An online, "live" version of this document (derived directly from -the mainline, development version of `g77' within `gcc') is available at -`http://www.gnu.org/software/gcc/onlinedocs/g77/News.html'. - - The following information was last updated on 2002-10-28: - -In `GCC' 3.2 versus `GCC' 3.1: -============================== - - * Problem Reports fixed (in chronological order of submission): - `8308' - gcc-3.x does not compile files with suffix .r (RATFOR) [Fixed - in 3.2.1] - -In `GCC' 3.1 (formerly known as g77-0.5.27) versus `GCC' 3.0: -============================================================= - - * Problem Reports fixed (in chronological order of submission): - `947' - Data statement initialization with subscript of kind INTEGER*2 - - `3743' - Reference to intrinsic `ISHFT' invalid - - `3807' - Function BESJN(integer,double) problems - - `3957' - g77 -pipe -xf77-cpp-input sends output to stdout - - `4279' - g77 -h" gives bogus output - - `4730' - ICE on valid input using CALL EXIT(%VAL(...)) - - `4752' - g77 -v -c -xf77-version /dev/null -xnone causes ice - - `4885' - BACKSPACE example that doesn't work as of gcc/g77-3.0.x - - `5122' - g77 rejects accepted use of INTEGER*2 as type of DATA - statement loop index - - `5397' - ICE on compiling source with 540 000 000 REAL array - - `5473' - ICE on BESJN(integer*8,real) - - `5837' - bug in loop unrolling - - * `g77' now has its man page generated from the texinfo - documentation, to guarantee that it remains up to date. - - * `g77' used to reject the following program on 32-bit targets: - PROGRAM PROG - DIMENSION A(140 000 000) - END - with the message: - prog.f: In program `prog': - prog.f:2: - DIMENSION A(140 000 000) - ^ - Array `a' at (^) is too large to handle - because 140 000 000 REALs is larger than the largest bit-extent - that can be expressed in 32 bits. However, bit-sizes never play a - role after offsets have been converted to byte addresses. - Therefore this check has been removed, and the limit is now 2 - Gbyte of memory (around 530 000 000 REALs). Note: On GNU/Linux - systems one has to compile programs that occupy more than 1 Gbyte - statically, i.e. `g77 -static ...'. - - * Based on work done by Juergen Pfeifer (<juergen.pfeifer@gmx.net>) - libf2c is now a shared library. One can still link in all objects - with the program by specifying the `-static' option. - - * Robert Anderson (<rwa@alumni.princeton.edu>) thought up a two line - change that enables g77 to compile such code as: - SUBROUTINE SUB(A, N) - DIMENSION N(2) - DIMENSION A(N(1),N(2)) - A(1,1) = 1. - END - Note the use of array elements in the bounds of the adjustable - array A. - - * George Helffrich (<george@geo.titech.ac.jp>) implemented a change - in substring index checking (when specifying `-fbounds-check') - that permits the use of zero length substrings of the form - `string(1:0)'. - - * Based on code developed by Pedro Vazquez - (<vazquez@penelope.iqm.unicamp.br>), the `libf2c' library is now - able to read and write files larger than 2 Gbyte on 32-bit target - machines, if the operating system supports this. - -In 0.5.26, `GCC' 3.0 versus `GCC' 2.95: -======================================= - - * When a REWIND was issued after a WRITE statement on an unformatted - file, the implicit truncation was performed by copying the - truncated file to /tmp and copying the result back. This has been - fixed by using the `ftruncate' OS function. Thanks go to the - GAMESS developers for bringing this to our attention. - - * Using options `-g', `-ggdb' or `-gdwarf[-2]' (where appropriate - for your target) now also enables debugging information for COMMON - BLOCK and EQUIVALENCE items to be emitted. Thanks go to Andrew - Vaught (<andy@xena.eas.asu.edu>) and George Helffrich - (<george@geology.bristol.ac.uk>) for fixing this longstanding - problem. - - * It is not necessary anymore to use the option `-femulate-complex' - to compile Fortran code using COMPLEX arithmetic, even on 64-bit - machines (like the Alpha). This will improve code generation. - - * INTRINSIC arithmetic functions are now treated as routines that do - not depend on anything but their argument(s). This enables - further instruction scheduling, because it is known that they - cannot read or modify arbitrary locations. - - * Upgrade to `libf2c' as of 2000-12-05. - - This fixes a bug where a namelist containing initialization of - LOGICAL items and a variable starting with T or F would be read - incorrectly. - - * The `TtyNam' intrinsics now set NAME to all spaces (at run time) - if the system has no `ttyname' implementation available. - - * Upgrade to `libf2c' as of 1999-06-28. - - This fixes a bug whereby input to a `NAMELIST' read involving a - repeat count, such as `K(5)=10*3', was not properly handled by - `libf2c'. The first item was written to `K(5)', but the remaining - nine were written elsewhere (still within the array), not - necessarily starting at `K(6)'. - -In 0.5.25, `GCC' 2.95 (`EGCS' 1.2) versus `EGCS' 1.1.2: -======================================================= - - * `g77' no longer generates bad code for assignments, or other - conversions, of `REAL' or `COMPLEX' constant expressions to type - `INTEGER(KIND=2)' (often referred to as `INTEGER*8'). - - For example, `INTEGER*8 J; J = 4E10' now works as documented. - - * `g77' no longer truncates `INTEGER(KIND=2)' (usually `INTEGER*8') - subscript expressions when evaluating array references on systems - with pointers widers than `INTEGER(KIND=1)' (such as Alphas). - - * `g77' no longer generates bad code for an assignment to a - `COMPLEX' variable or array that partially overlaps one or more of - the sources of the same assignment (a very rare construction). It - now assigns through a temporary, in cases where such partial - overlap is deemed possible. - - * `libg2c' (`libf2c') no longer loses track of the file being worked - on during a `BACKSPACE' operation. - - * `libg2c' (`libf2c') fixes a bug whereby input to a `NAMELIST' read - involving a repeat count, such as `K(5)=10*3', was not properly - handled by `libf2c'. The first item was written to `K(5)', but - the remaining nine were written elsewhere (still within the array), - not necessarily starting at `K(6)'. - - * Automatic arrays now seem to be working on HP-UX systems. - - * The `Date' intrinsic now returns the correct result on big-endian - systems. - - * Fix `g77' so it no longer crashes when compiling I/O statements - using keywords that define `INTEGER' values, such as `IOSTAT=J', - where J is other than default `INTEGER' (such as `INTEGER*2'). - Instead, it issues a diagnostic. - - * Fix `g77' so it properly handles `DATA A/RPT*VAL/', where RPT is - not default `INTEGER', such as `INTEGER*2', instead of producing a - spurious diagnostic. Also fix `DATA (A(I),I=1,N)', where `N' is - not default `INTEGER' to work instead of crashing `g77'. - - * The `-ax' option is now obeyed when compiling Fortran programs. - (It is passed to the `f771' driver.) - - * The new `-fbounds-check' option causes `g77' to compile run-time - bounds checks of array subscripts, as well as of substring start - and end points. - - * `libg2c' now supports building as multilibbed library, which - provides better support for systems that require options such as - `-mieee' to work properly. - - * Source file names with the suffixes `.FOR' and `.FPP' now are - recognized by `g77' as if they ended in `.for' and `.fpp', - respectively. - - * The order of arguments to the _subroutine_ forms of the `CTime', - `DTime', `ETime', and `TtyNam' intrinsics has been swapped. The - argument serving as the returned value for the corresponding - function forms now is the _second_ argument, making these - consistent with the other subroutine forms of `libU77' intrinsics. - - * `g77' now warns about a reference to an intrinsic that has an - interface that is not Year 2000 (Y2K) compliant. Also, `libg2c' - has been changed to increase the likelihood of catching references - to the implementations of these intrinsics using the `EXTERNAL' - mechanism (which would avoid the new warnings). - - * `g77' now warns about a reference to a function when the - corresponding _subsequent_ function program unit disagrees with - the reference concerning the type of the function. - - * `-fno-emulate-complex' is now the default option. This should - result in improved performance of code that uses the `COMPLEX' - data type. - - * The `-malign-double' option now reliably aligns _all_ - double-precision variables and arrays on Intel x86 targets. - - * Even without the `-malign-double' option, `g77' reliably aligns - local double-precision variables that are not in `EQUIVALENCE' - areas and not `SAVE''d. - - * `g77' now open-codes ("inlines") division of `COMPLEX' operands - instead of generating a run-time call to the `libf2c' routines - `c_div' or `z_div', unless the `-Os' option is specified. - - * `g77' no longer generates code to maintain `errno', a C-language - concept, when performing operations such as the `SqRt' intrinsic. - - * `g77' developers can temporarily use the `-fflatten-arrays' option - to compare how the compiler handles code generation using C-like - constructs as compared to the Fortran-like method constructs - normally used. - - * A substantial portion of the `g77' front end's code-generation - component was rewritten. It now generates code using facilities - more robustly supported by the `gcc' back end. One effect of this - rewrite is that some codes no longer produce a spurious "label LAB - used before containing binding contour" message. - - * Support for the `-fugly' option has been removed. - - * Improve documentation and indexing, including information on Year - 2000 (Y2K) compliance, and providing more information on internals - of the front end. - - * Upgrade to `libf2c' as of 1999-05-10. - -In 0.5.24 versus 0.5.23: -======================== - - There is no `g77' version 0.5.24 at this time, or planned. 0.5.24 -is the version number designated for bug fixes and, perhaps, some new -features added, to 0.5.23. Version 0.5.23 requires `gcc' 2.8.1, as -0.5.24 was planned to require. - - Due to `EGCS' becoming `GCC' (which is now an acronym for "GNU -Compiler Collection"), and `EGCS' 1.2 becoming officially designated -`GCC' 2.95, there seems to be no need for an actual 0.5.24 release. - - To reduce the confusion already resulting from use of 0.5.24 to -designate `g77' versions within `EGCS' versions 1.0 and 1.1, as well as -in versions of `g77' documentation and notices during that period, -"mainline" `g77' version numbering resumes at 0.5.25 with `GCC' 2.95 -(`EGCS' 1.2), skipping over 0.5.24 as a placeholder version number. - - To repeat, there is no `g77' 0.5.24, but there is now a 0.5.25. -Please remain calm and return to your keypunch units. - -In `EGCS' 1.1.2 versus `EGCS' 1.1.1: -==================================== - - * Fix the `IDate' intrinsic (VXT) (in `libg2c') so the returned year - is in the documented, non-Y2K-compliant range of 0-99, instead of - being returned as 100 in the year 2000. - - * Fix the `Date_and_Time' intrinsic (in `libg2c') to return the - milliseconds value properly in VALUES(8). - - * Fix the `LStat' intrinsic (in `libg2c') to return device-ID - information properly in SARRAY(7). - - * Improve documentation. - -In `EGCS' 1.1.1 versus `EGCS' 1.1: -================================== - - * Fix `libg2c' so it performs an implicit `ENDFILE' operation (as - appropriate) whenever a `REWIND' is done. - - (This bug was introduced in 0.5.23 and `egcs' 1.1 in `g77''s - version of `libf2c'.) - - * Fix `libg2c' so it no longer crashes with a spurious diagnostic - upon doing any I/O following a direct formatted write. - - (This bug was introduced in 0.5.23 and `egcs' 1.1 in `g77''s - version of `libf2c'.) - - * Fix `g77' so it no longer crashes compiling references to the - `Rand' intrinsic on some systems. - - * Fix `g77' portion of installation process so it works better on - some systems (those with shells requiring `else true' clauses on - `if' constructs for the completion code to be set properly). - -In `EGCS' 1.1 versus `EGCS' 1.0.3: -================================== - - * Fix bugs in the `libU77' intrinsic `HostNm' that wrote one byte - beyond the end of its `CHARACTER' argument, and in the `libU77' - intrinsics `GMTime' and `LTime' that overwrote their arguments. - - * Assumed arrays with negative bounds (such as `REAL A(-1:*)') no - longer elicit spurious diagnostics from `g77', even on systems - with pointers having different sizes than integers. - - This bug is not known to have existed in any recent version of - `gcc'. It was introduced in an early release of `egcs'. - - * Valid combinations of `EXTERNAL', passing that external as a dummy - argument without explicitly giving it a type, and, in a subsequent - program unit, referencing that external as an external function - with a different type no longer crash `g77'. - - * `CASE DEFAULT' no longer crashes `g77'. - - * The `-Wunused' option no longer issues a spurious warning about - the "master" procedure generated by `g77' for procedures - containing `ENTRY' statements. - - * Support `FORMAT(I<EXPR>)' when EXPR is a compile-time constant - `INTEGER' expression. - - * Fix `g77' `-g' option so procedures that use `ENTRY' can be - stepped through, line by line, in `gdb'. - - * Allow any `REAL' argument to intrinsics `Second' and `CPU_Time'. - - * Use `tempnam', if available, to open scratch files (as in - `OPEN(STATUS='SCRATCH')') so that the `TMPDIR' environment - variable, if present, is used. - - * `g77''s version of `libf2c' separates out the setting of global - state (such as command-line arguments and signal handling) from - `main.o' into distinct, new library archive members. - - This should make it easier to write portable applications that - have their own (non-Fortran) `main()' routine properly set up the - `libf2c' environment, even when `libf2c' (now `libg2c') is a - shared library. - - * `g77' no longer installs the `f77' command and `f77.1' man page in - the `/usr' or `/usr/local' hierarchy, even if the `f77-install-ok' - file exists in the source or build directory. See the - installation documentation for more information. - - * `g77' no longer installs the `libf2c.a' library and `f2c.h' - include file in the `/usr' or `/usr/local' hierarchy, even if the - `f2c-install-ok' or `f2c-exists-ok' files exist in the source or - build directory. See the installation documentation for more - information. - - * The `libf2c.a' library produced by `g77' has been renamed to - `libg2c.a'. It is installed only in the `gcc' "private" directory - hierarchy, `gcc-lib'. This allows system administrators and users - to choose which version of the `libf2c' library from `netlib' they - wish to use on a case-by-case basis. See the installation - documentation for more information. - - * The `f2c.h' include (header) file produced by `g77' has been - renamed to `g2c.h'. It is installed only in the `gcc' "private" - directory hierarchy, `gcc-lib'. This allows system administrators - and users to choose which version of the include file from - `netlib' they wish to use on a case-by-case basis. See the - installation documentation for more information. - - * The `g77' command now expects the run-time library to be named - `libg2c.a' instead of `libf2c.a', to ensure that a version other - than the one built and installed as part of the same `g77' version - is picked up. - - * During the configuration and build process, `g77' creates - subdirectories it needs only as it needs them. Other cleaning up - of the configuration and build process has been performed as well. - - * `install-info' now used to update the directory of Info - documentation to contain an entry for `g77' (during installation). - - * Some diagnostics have been changed from warnings to errors, to - prevent inadvertent use of the resulting, probably buggy, programs. - These mostly include diagnostics about use of unsupported features - in the `OPEN', `INQUIRE', `READ', and `WRITE' statements, and - about truncations of various sorts of constants. - - * Improve compilation of `FORMAT' expressions so that a null byte is - appended to the last operand if it is a constant. This provides a - cleaner run-time diagnostic as provided by `libf2c' for statements - like `PRINT '(I1', 42'. - - * Improve documentation and indexing. - - * The upgrade to `libf2c' as of 1998-06-18 should fix a variety of - problems, including those involving some uses of the `T' format - specifier, and perhaps some build (porting) problems as well. - -In `EGCS' 1.1 versus `g77' 0.5.23: -================================== - - * Fix a code-generation bug that afflicted Intel x86 targets when - `-O2' was specified compiling, for example, an old version of the - `DNRM2' routine. - - The x87 coprocessor stack was being mismanaged in cases involving - assigned `GOTO' and `ASSIGN'. - - * `g77' no longer produces incorrect code and initial values for - `EQUIVALENCE' and `COMMON' aggregates that, due to "unnatural" - ordering of members vis-a-vis their types, require initial padding. - - * Fix `g77' crash compiling code containing the construct - `CMPLX(0.)' or similar. - - * `g77' no longer crashes when compiling code containing - specification statements such as `INTEGER(KIND=7) PTR'. - - * `g77' no longer crashes when compiling code such as `J = SIGNAL(1, - 2)'. - - * `g77' now treats `%LOC(EXPR)' and `LOC(EXPR)' as "ordinary" - expressions when they are used as arguments in procedure calls. - This change applies only to global (filewide) analysis, making it - consistent with how `g77' actually generates code for these cases. - - Previously, `g77' treated these expressions as denoting special - "pointer" arguments for the purposes of filewide analysis. - - * Fix `g77' crash (or apparently infinite run-time) when compiling - certain complicated expressions involving `COMPLEX' arithmetic - (especially multiplication). - - * Align static double-precision variables and arrays on Intel x86 - targets regardless of whether `-malign-double' is specified. - - Generally, this affects only local variables and arrays having the - `SAVE' attribute or given initial values via `DATA'. - - * The `g77' driver now ensures that `-lg2c' is specified in the link - phase prior to any occurrence of `-lm'. This prevents - accidentally linking to a routine in the SunOS4 `-lm' library when - the generated code wants to link to the one in `libf2c' (`libg2c'). - - * `g77' emits more debugging information when `-g' is used. - - This new information allows, for example, `which __g77_length_a' - to be used in `gdb' to determine the type of the phantom length - argument supplied with `CHARACTER' variables. - - This information pertains to internally-generated type, variable, - and other information, not to the longstanding deficiencies - vis-a-vis `COMMON' and `EQUIVALENCE'. - - * The F90 `Date_and_Time' intrinsic now is supported. - - * The F90 `System_Clock' intrinsic allows the optional arguments - (except for the `Count' argument) to be omitted. - - * Upgrade to `libf2c' as of 1998-06-18. - - * Improve documentation and indexing. - -In previous versions: -===================== - - Information on previous versions is not provided in this -`gcc/gcc/f/NEWS' file, to keep it short. See `gcc/gcc/f/news.texi', or -any of its other derivations (Info, HTML, dvi forms) for such -information. - diff --git a/contrib/gcc/f/g77.1 b/contrib/gcc/f/g77.1 deleted file mode 100644 index 91af9e0a5eca..000000000000 --- a/contrib/gcc/f/g77.1 +++ /dev/null @@ -1,1719 +0,0 @@ -.\" Automatically generated by Pod::Man version 1.15 -.\" Wed Feb 5 03:13:59 2003 -.\" -.\" Standard preamble: -.\" ====================================================================== -.de Sh \" Subsection heading -.br -.if t .Sp -.ne 5 -.PP -\fB\\$1\fR -.PP -.. -.de Sp \" Vertical space (when we can't use .PP) -.if t .sp .5v -.if n .sp -.. -.de Ip \" List item -.br -.ie \\n(.$>=3 .ne \\$3 -.el .ne 3 -.IP "\\$1" \\$2 -.. -.de Vb \" Begin verbatim text -.ft CW -.nf -.ne \\$1 -.. -.de Ve \" End verbatim text -.ft R - -.fi -.. -.\" Set up some character translations and predefined strings. \*(-- will -.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left -.\" double quote, and \*(R" will give a right double quote. | will give a -.\" real vertical bar. \*(C+ will give a nicer C++. Capital omega is used -.\" to do unbreakable dashes and therefore won't be available. \*(C` and -.\" \*(C' expand to `' in nroff, nothing in troff, for use with C<> -.tr \(*W-|\(bv\*(Tr -.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' -.ie n \{\ -. ds -- \(*W- -. ds PI pi -. if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch -. if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch -. ds L" "" -. ds R" "" -. ds C` "" -. ds C' "" -'br\} -.el\{\ -. ds -- \|\(em\| -. ds PI \(*p -. ds L" `` -. ds R" '' -'br\} -.\" -.\" If the F register is turned on, we'll generate index entries on stderr -.\" for titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and -.\" index entries marked with X<> in POD. Of course, you'll have to process -.\" the output yourself in some meaningful fashion. -.if \nF \{\ -. de IX -. tm Index:\\$1\t\\n%\t"\\$2" -.. -. nr % 0 -. rr F -.\} -.\" -.\" For nroff, turn off justification. 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No user-serviceable parts. -.bd B 3 -. \" fudge factors for nroff and troff -.if n \{\ -. ds #H 0 -. ds #V .8m -. ds #F .3m -. ds #[ \f1 -. ds #] \fP -.\} -.if t \{\ -. ds #H ((1u-(\\\\n(.fu%2u))*.13m) -. ds #V .6m -. ds #F 0 -. ds #[ \& -. ds #] \& -.\} -. \" simple accents for nroff and troff -.if n \{\ -. ds ' \& -. ds ` \& -. ds ^ \& -. ds , \& -. ds ~ ~ -. ds / -.\} -.if t \{\ -. ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" -. ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' -. ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' -. ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' -. ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' -. ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' -.\} -. \" troff and (daisy-wheel) nroff accents -.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' -.ds 8 \h'\*(#H'\(*b\h'-\*(#H' -.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#] -.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H' -.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u' -.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#] -.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#] -.ds ae a\h'-(\w'a'u*4/10)'e -.ds Ae A\h'-(\w'A'u*4/10)'E -. \" corrections for vroff -.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u' -.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u' -. \" for low resolution devices (crt and lpr) -.if \n(.H>23 .if \n(.V>19 \ -\{\ -. ds : e -. ds 8 ss -. ds o a -. ds d- d\h'-1'\(ga -. ds D- D\h'-1'\(hy -. ds th \o'bp' -. ds Th \o'LP' -. ds ae ae -. ds Ae AE -.\} -.rm #[ #] #H #V #F C -.\" ====================================================================== -.\" -.IX Title "G77 1" -.TH G77 1 "gcc-3.2.2" "2003-02-05" "GNU" -.UC -.SH "NAME" -g77 \- \s-1GNU\s0 project Fortran 77 compiler -.SH "SYNOPSIS" -.IX Header "SYNOPSIS" -g77 [\fB\-c\fR|\fB\-S\fR|\fB\-E\fR] - [\fB\-g\fR] [\fB\-pg\fR] [\fB\-O\fR\fIlevel\fR] - [\fB\-W\fR\fIwarn\fR...] [\fB\-pedantic\fR] - [\fB\-I\fR\fIdir\fR...] [\fB\-L\fR\fIdir\fR...] - [\fB\-D\fR\fImacro\fR[=\fIdefn\fR]...] [\fB\-U\fR\fImacro\fR] - [\fB\-f\fR\fIoption\fR...] [\fB\-m\fR\fImachine-option\fR...] - [\fB\-o\fR \fIoutfile\fR] \fIinfile\fR... -.PP -Only the most useful options are listed here; see below for the -remainder. -.SH "DESCRIPTION" -.IX Header "DESCRIPTION" -The \fBg77\fR command supports all the options supported by the -\&\fBgcc\fR command. -.PP -All \fBgcc\fR and \fBg77\fR options -are accepted both by \fBg77\fR and by \fBgcc\fR -(as well as any other drivers built at the same time, -such as \fBg++\fR), -since adding \fBg77\fR to the \fBgcc\fR distribution -enables acceptance of \fBg77\fR options -by all of the relevant drivers. -.PP -In some cases, options have positive and negative forms; -the negative form of \fB\-ffoo\fR would be \fB\-fno-foo\fR. -This manual documents only one of these two forms, whichever -one is not the default. -.SH "OPTIONS" -.IX Header "OPTIONS" -Here is a summary of all the options specific to \s-1GNU\s0 Fortran, grouped -by type. Explanations are in the following sections. -.Ip "\fIOverall Options\fR" 4 -.IX Item "Overall Options" -\&\fB\-fversion \-fset-g77\-defaults \-fno-silent\fR -.Ip "\fIShorthand Options\fR" 4 -.IX Item "Shorthand Options" -\&\fB\-ff66 \-fno-f66 \-ff77 \-fno-f77 \-fno-ugly\fR -.Ip "\fIFortran Language Options\fR" 4 -.IX Item "Fortran Language Options" -\&\fB\-ffree-form \-fno-fixed-form \-ff90 -\&\-fvxt \-fdollar-ok \-fno-backslash -\&\-fno-ugly-args \-fno-ugly-assign \-fno-ugly-assumed -\&\-fugly-comma \-fugly-complex \-fugly-init \-fugly-logint -\&\-fonetrip \-ftypeless-boz -\&\-fintrin-case-initcap \-fintrin-case-upper -\&\-fintrin-case-lower \-fintrin-case-any -\&\-fmatch-case-initcap \-fmatch-case-upper -\&\-fmatch-case-lower \-fmatch-case-any -\&\-fsource-case-upper \-fsource-case-lower -\&\-fsource-case-preserve -\&\-fsymbol-case-initcap \-fsymbol-case-upper -\&\-fsymbol-case-lower \-fsymbol-case-any -\&\-fcase-strict-upper \-fcase-strict-lower -\&\-fcase-initcap \-fcase-upper \-fcase-lower \-fcase-preserve -\&\-ff2c-intrinsics-delete \-ff2c-intrinsics-hide -\&\-ff2c-intrinsics-disable \-ff2c-intrinsics-enable -\&\-fbadu77\-intrinsics-delete \-fbadu77\-intrinsics-hide -\&\-fbadu77\-intrinsics-disable \-fbadu77\-intrinsics-enable -\&\-ff90\-intrinsics-delete \-ff90\-intrinsics-hide -\&\-ff90\-intrinsics-disable \-ff90\-intrinsics-enable -\&\-fgnu-intrinsics-delete \-fgnu-intrinsics-hide -\&\-fgnu-intrinsics-disable \-fgnu-intrinsics-enable -\&\-fmil-intrinsics-delete \-fmil-intrinsics-hide -\&\-fmil-intrinsics-disable \-fmil-intrinsics-enable -\&\-funix-intrinsics-delete \-funix-intrinsics-hide -\&\-funix-intrinsics-disable \-funix-intrinsics-enable -\&\-fvxt-intrinsics-delete \-fvxt-intrinsics-hide -\&\-fvxt-intrinsics-disable \-fvxt-intrinsics-enable -\&\-ffixed-line-length-\fR\fIn\fR \fB\-ffixed-line-length-none\fR -.Ip "\fIWarning Options\fR" 4 -.IX Item "Warning Options" -\&\fB\-fsyntax-only \-pedantic \-pedantic-errors \-fpedantic -\&\-w \-Wno-globals \-Wimplicit \-Wunused \-Wuninitialized -\&\-Wall \-Wsurprising -\&\-Werror \-W\fR -.Ip "\fIDebugging Options\fR" 4 -.IX Item "Debugging Options" -\&\fB\-g\fR -.Ip "\fIOptimization Options\fR" 4 -.IX Item "Optimization Options" -\&\fB\-malign-double -\&\-ffloat-store \-fforce-mem \-fforce-addr \-fno-inline -\&\-ffast-math \-fstrength-reduce \-frerun-cse-after-loop -\&\-funsafe-math-optimizations \-fno-trapping-math -\&\-fexpensive-optimizations \-fdelayed-branch -\&\-fschedule-insns \-fschedule-insn2 \-fcaller-saves -\&\-funroll-loops \-funroll-all-loops -\&\-fno-move-all-movables \-fno-reduce-all-givs -\&\-fno-rerun-loop-opt\fR -.Ip "\fIDirectory Options\fR" 4 -.IX Item "Directory Options" -\&\fB\-I\fR\fIdir\fR \fB\-I-\fR -.Ip "\fICode Generation Options\fR" 4 -.IX Item "Code Generation Options" -\&\fB\-fno-automatic \-finit-local-zero \-fno-f2c -\&\-ff2c-library \-fno-underscoring \-fno-ident -\&\-fpcc-struct-return \-freg-struct-return -\&\-fshort-double \-fno-common \-fpack-struct -\&\-fzeros \-fno-second-underscore -\&\-femulate-complex -\&\-falias-check \-fargument-alias -\&\-fargument-noalias \-fno-argument-noalias-global -\&\-fno-globals \-fflatten-arrays -\&\-fbounds-check \-ffortran-bounds-check\fR -.PP -Compilation can involve as many as four stages: preprocessing, code -generation (often what is really meant by the term ``compilation''), -assembly, and linking, always in that order. The first three -stages apply to an individual source file, and end by producing an -object file; linking combines all the object files (those newly -compiled, and those specified as input) into an executable file. -.PP -For any given input file, the file name suffix determines what kind of -program is contained in the file\-\-\-that is, the language in which the -program is written is generally indicated by the suffix. -Suffixes specific to \s-1GNU\s0 Fortran are listed below. -.Ip "\fIfile\fR\fB.f\fR" 4 -.IX Item "file.f" -.PD 0 -.Ip "\fIfile\fR\fB.for\fR" 4 -.IX Item "file.for" -.Ip "\fIfile\fR\fB.FOR\fR" 4 -.IX Item "file.FOR" -.PD -Fortran source code that should not be preprocessed. -.Sp -Such source code cannot contain any preprocessor directives, such -as \f(CW\*(C`#include\*(C'\fR, \f(CW\*(C`#define\*(C'\fR, \f(CW\*(C`#if\*(C'\fR, and so on. -.Sp -You can force \fB.f\fR files to be preprocessed by \fBcpp\fR by using -\&\fB\-x f77\-cpp-input\fR. -.Ip "\fIfile\fR\fB.F\fR" 4 -.IX Item "file.F" -.PD 0 -.Ip "\fIfile\fR\fB.fpp\fR" 4 -.IX Item "file.fpp" -.Ip "\fIfile\fR\fB.FPP\fR" 4 -.IX Item "file.FPP" -.PD -Fortran source code that must be preprocessed (by the C preprocessor -\&\fBcpp\fR, which is part of \s-1GNU\s0 \s-1CC\s0). -.Sp -Note that preprocessing is not extended to the contents of -files included by the \f(CW\*(C`INCLUDE\*(C'\fR directive\-\-\-the \f(CW\*(C`#include\*(C'\fR -preprocessor directive must be used instead. -.Ip "\fIfile\fR\fB.r\fR" 4 -.IX Item "file.r" -Ratfor source code, which must be preprocessed by the \fBratfor\fR -command, which is available separately (as it is not yet part of the \s-1GNU\s0 -Fortran distribution). -One version in Fortran, adapted for use with \fBg77\fR is at -<\fBftp://members.aol.com/n8tm/rat7.uue\fR> (of uncertain copyright -status). Another, public domain version in C is at -<\fBhttp://sepwww.stanford.edu/sep/prof/ratfor.shar.2\fR>. -.PP -\&\s-1UNIX\s0 users typically use the \fI\fIfile\fI.f\fR and \fI\fIfile\fI.F\fR -nomenclature. -Users of other operating systems, especially those that cannot -distinguish upper-case -letters from lower-case letters in their file names, typically use -the \fI\fIfile\fI.for\fR and \fI\fIfile\fI.fpp\fR nomenclature. -.PP -Use of the preprocessor \fBcpp\fR allows use of C-like -constructs such as \f(CW\*(C`#define\*(C'\fR and \f(CW\*(C`#include\*(C'\fR, but can -lead to unexpected, even mistaken, results due to Fortran's source file -format. -It is recommended that use of the C preprocessor -be limited to \f(CW\*(C`#include\*(C'\fR and, in -conjunction with \f(CW\*(C`#define\*(C'\fR, only \f(CW\*(C`#if\*(C'\fR and related directives, -thus avoiding in-line macro expansion entirely. -This recommendation applies especially -when using the traditional fixed source form. -With free source form, -fewer unexpected transformations are likely to happen, but use of -constructs such as Hollerith and character constants can nevertheless -present problems, especially when these are continued across multiple -source lines. -These problems result, primarily, from differences between the way -such constants are interpreted by the C preprocessor and by a Fortran -compiler. -.PP -Another example of a problem that results from using the C preprocessor -is that a Fortran comment line that happens to contain any -characters ``interesting'' to the C preprocessor, -such as a backslash at the end of the line, -is not recognized by the preprocessor as a comment line, -so instead of being passed through ``raw'', -the line is edited according to the rules for the preprocessor. -For example, the backslash at the end of the line is removed, -along with the subsequent newline, resulting in the next -line being effectively commented out\-\-\-unfortunate if that -line is a non-comment line of important code! -.PP -\&\fINote:\fR The \fB\-traditional\fR and \fB\-undef\fR flags are supplied -to \fBcpp\fR by default, to help avoid unpleasant surprises. -.PP -This means that \s-1ANSI\s0 C preprocessor features (such as the \fB#\fR -operator) aren't available, and only variables in the C reserved -namespace (generally, names with a leading underscore) are liable to -substitution by C predefines. -Thus, if you want to do system-specific -tests, use, for example, \fB#ifdef _\|_linux_\|_\fR rather than \fB#ifdef linux\fR. -Use the \fB\-v\fR option to see exactly how the preprocessor is invoked. -.PP -Unfortunately, the \fB\-traditional\fR flag will not avoid an error from -anything that \fBcpp\fR sees as an unterminated C comment, such as: -.PP -.Vb 2 -\& C Some Fortran compilers accept /* as starting -\& C an inline comment. -.Ve -The following options that affect overall processing are recognized -by the \fBg77\fR and \fBgcc\fR commands in a \s-1GNU\s0 Fortran installation: -.Ip "\fB\-fversion\fR" 4 -.IX Item "-fversion" -Ensure that the \fBg77\fR version of the compiler phase is reported, -if run, -and, starting in \f(CW\*(C`egcs\*(C'\fR version 1.1, -that internal consistency checks in the \fIf771\fR program are run. -.Sp -This option is supplied automatically when \fB\-v\fR or \fB\*(--verbose\fR -is specified as a command-line option for \fBg77\fR or \fBgcc\fR -and when the resulting commands compile Fortran source files. -.Sp -In \s-1GCC\s0 3.1, this is changed back to the behaviour \fBgcc\fR displays -for \fB.c\fR files. -.Ip "\fB\-fset-g77\-defaults\fR" 4 -.IX Item "-fset-g77-defaults" -\&\fIVersion info:\fR -This option was obsolete as of \f(CW\*(C`egcs\*(C'\fR -version 1.1. -The effect is instead achieved -by the \f(CW\*(C`lang_init_options\*(C'\fR routine -in \fIgcc/gcc/f/com.c\fR. -.Sp -Set up whatever \fBgcc\fR options are to apply to Fortran -compilations, and avoid running internal consistency checks -that might take some time. -.Sp -This option is supplied automatically when compiling Fortran code -via the \fBg77\fR or \fBgcc\fR command. -The description of this option is provided so that users seeing -it in the output of, say, \fBg77 \-v\fR understand why it is -there. -.Sp -Also, developers who run \f(CW\*(C`f771\*(C'\fR directly might want to specify it -by hand to get the same defaults as they would running \f(CW\*(C`f771\*(C'\fR -via \fBg77\fR or \fBgcc\fR -However, such developers should, after linking a new \f(CW\*(C`f771\*(C'\fR -executable, invoke it without this option once, -e.g. via \f(CW\*(C`./f771 \-quiet < /dev/null\*(C'\fR, -to ensure that they have not introduced any -internal inconsistencies (such as in the table of -intrinsics) before proceeding\-\--\fBg77\fR will crash -with a diagnostic if it detects an inconsistency. -.Ip "\fB\-fno-silent\fR" 4 -.IX Item "-fno-silent" -Print (to \f(CW\*(C`stderr\*(C'\fR) the names of the program units as -they are compiled, in a form similar to that used by popular -\&\s-1UNIX\s0 \fBf77\fR implementations and \fBf2c\fR -.Sh "Shorthand Options" -.IX Subsection "Shorthand Options" -The following options serve as ``shorthand'' -for other options accepted by the compiler: -.Ip "\fB\-fugly\fR" 4 -.IX Item "-fugly" -\&\fINote:\fR This option is no longer supported. -The information, below, is provided to aid -in the conversion of old scripts. -.Sp -Specify that certain ``ugly'' constructs are to be quietly accepted. -Same as: -.Sp -.Vb 3 -\& -fugly-args -fugly-assign -fugly-assumed -\& -fugly-comma -fugly-complex -fugly-init -\& -fugly-logint -.Ve -These constructs are considered inappropriate to use in new -or well-maintained portable Fortran code, but widely used -in old code. -.Ip "\fB\-fno-ugly\fR" 4 -.IX Item "-fno-ugly" -Specify that all ``ugly'' constructs are to be noisily rejected. -Same as: -.Sp -.Vb 3 -\& -fno-ugly-args -fno-ugly-assign -fno-ugly-assumed -\& -fno-ugly-comma -fno-ugly-complex -fno-ugly-init -\& -fno-ugly-logint -.Ve -.Ip "\fB\-ff66\fR" 4 -.IX Item "-ff66" -Specify that the program is written in idiomatic \s-1FORTRAN\s0 66. -Same as \fB\-fonetrip \-fugly-assumed\fR. -.Sp -The \fB\-fno-f66\fR option is the inverse of \fB\-ff66\fR. -As such, it is the same as \fB\-fno-onetrip \-fno-ugly-assumed\fR. -.Sp -The meaning of this option is likely to be refined as future -versions of \fBg77\fR provide more compatibility with other -existing and obsolete Fortran implementations. -.Ip "\fB\-ff77\fR" 4 -.IX Item "-ff77" -Specify that the program is written in idiomatic \s-1UNIX\s0 \s-1FORTRAN\s0 77 -and/or the dialect accepted by the \fBf2c\fR product. -Same as \fB\-fbackslash \-fno-typeless-boz\fR. -.Sp -The meaning of this option is likely to be refined as future -versions of \fBg77\fR provide more compatibility with other -existing and obsolete Fortran implementations. -.Ip "\fB\-fno-f77\fR" 4 -.IX Item "-fno-f77" -The \fB\-fno-f77\fR option is \fInot\fR the inverse -of \fB\-ff77\fR. -It specifies that the program is not written in idiomatic \s-1UNIX\s0 -\&\s-1FORTRAN\s0 77 or \fBf2c\fR but in a more widely portable dialect. -\&\fB\-fno-f77\fR is the same as \fB\-fno-backslash\fR. -.Sp -The meaning of this option is likely to be refined as future -versions of \fBg77\fR provide more compatibility with other -existing and obsolete Fortran implementations. -.Sh "Options Controlling Fortran Dialect" -.IX Subsection "Options Controlling Fortran Dialect" -The following options control the dialect of Fortran -that the compiler accepts: -.Ip "\fB\-ffree-form\fR" 4 -.IX Item "-ffree-form" -.PD 0 -.Ip "\fB\-fno-fixed-form\fR" 4 -.IX Item "-fno-fixed-form" -.PD -Specify that the source file is written in free form -(introduced in Fortran 90) instead of the more-traditional fixed form. -.Ip "\fB\-ff90\fR" 4 -.IX Item "-ff90" -Allow certain Fortran-90 constructs. -.Sp -This option controls whether certain -Fortran 90 constructs are recognized. -(Other Fortran 90 constructs -might or might not be recognized depending on other options such as -\&\fB\-fvxt\fR, \fB\-ff90\-intrinsics-enable\fR, and the -current level of support for Fortran 90.) -.Ip "\fB\-fvxt\fR" 4 -.IX Item "-fvxt" -Specify the treatment of certain constructs that have different -meanings depending on whether the code is written in -\&\s-1GNU\s0 Fortran (based on \s-1FORTRAN\s0 77 and akin to Fortran 90) -or \s-1VXT\s0 Fortran (more like \s-1VAX\s0 \s-1FORTRAN\s0). -.Sp -The default is \fB\-fno-vxt\fR. -\&\fB\-fvxt\fR specifies that the \s-1VXT\s0 Fortran interpretations -for those constructs are to be chosen. -.Ip "\fB\-fdollar-ok\fR" 4 -.IX Item "-fdollar-ok" -Allow \fB$\fR as a valid character in a symbol name. -.Ip "\fB\-fno-backslash\fR" 4 -.IX Item "-fno-backslash" -Specify that \fB\e\fR is not to be specially interpreted in character -and Hollerith constants a la C and many \s-1UNIX\s0 Fortran compilers. -.Sp -For example, with \fB\-fbackslash\fR in effect, \fBA\enB\fR specifies -three characters, with the second one being newline. -With \fB\-fno-backslash\fR, it specifies four characters, -\&\fBA\fR, \fB\e\fR, \fBn\fR, and \fBB\fR. -.Sp -Note that \fBg77\fR implements a fairly general form of backslash -processing that is incompatible with the narrower forms supported -by some other compilers. -For example, \fB'A\e003B'\fR is a three-character string in \fBg77\fR -whereas other compilers that support backslash might not support -the three-octal-digit form, and thus treat that string as longer -than three characters. -.Ip "\fB\-fno-ugly-args\fR" 4 -.IX Item "-fno-ugly-args" -Disallow passing Hollerith and typeless constants as actual -arguments (for example, \fB\s-1CALL\s0 FOO(4HABCD)\fR). -.Ip "\fB\-fugly-assign\fR" 4 -.IX Item "-fugly-assign" -Use the same storage for a given variable regardless of -whether it is used to hold an assigned-statement label -(as in \fB\s-1ASSIGN\s0 10 \s-1TO\s0 I\fR) or used to hold numeric data -(as in \fBI = 3\fR). -.Ip "\fB\-fugly-assumed\fR" 4 -.IX Item "-fugly-assumed" -Assume any dummy array with a final dimension specified as \fB1\fR -is really an assumed-size array, as if \fB*\fR had been specified -for the final dimension instead of \fB1\fR. -.Sp -For example, \fB\s-1DIMENSION\s0 X(1)\fR is treated as if it -had read \fB\s-1DIMENSION\s0 X(*)\fR. -.Ip "\fB\-fugly-comma\fR" 4 -.IX Item "-fugly-comma" -In an external-procedure invocation, -treat a trailing comma in the argument list -as specification of a trailing null argument, -and treat an empty argument list -as specification of a single null argument. -.Sp -For example, \fB\s-1CALL\s0 \f(BIFOO\fB\|(,)\fR is treated as -\&\fB\s-1CALL\s0 FOO(%\f(BIVAL\fB\|(0), %\f(BIVAL\fB\|(0))\fR. -That is, \fItwo\fR null arguments are specified -by the procedure call when \fB\-fugly-comma\fR is in force. -And \fBF = \f(BIFUNC()\fB\fR is treated as \fBF = FUNC(%\f(BIVAL\fB\|(0))\fR. -.Sp -The default behavior, \fB\-fno-ugly-comma\fR, is to ignore -a single trailing comma in an argument list. -So, by default, \fB\s-1CALL\s0 FOO(X,)\fR is treated -exactly the same as \fB\s-1CALL\s0 \f(BIFOO\fB\|(X)\fR. -.Ip "\fB\-fugly-complex\fR" 4 -.IX Item "-fugly-complex" -Do not complain about \fBREAL(\fR\fIexpr\fR\fB)\fR or -\&\fBAIMAG(\fR\fIexpr\fR\fB)\fR when \fIexpr\fR is a \f(CW\*(C`COMPLEX\*(C'\fR -type other than \f(CW\*(C`COMPLEX(KIND=1)\*(C'\fR\-\-\-usually -this is used to permit \f(CW\*(C`COMPLEX(KIND=2)\*(C'\fR -(\f(CW\*(C`DOUBLE COMPLEX\*(C'\fR) operands. -.Sp -The \fB\-ff90\fR option controls the interpretation -of this construct. -.Ip "\fB\-fno-ugly-init\fR" 4 -.IX Item "-fno-ugly-init" -Disallow use of Hollerith and typeless constants as initial -values (in \f(CW\*(C`PARAMETER\*(C'\fR and \f(CW\*(C`DATA\*(C'\fR statements), and -use of character constants to -initialize numeric types and vice versa. -.Sp -For example, \fB\s-1DATA\s0 I/'F'/, \s-1CHRVAR/65/\s0, J/4HABCD/\fR is disallowed by -\&\fB\-fno-ugly-init\fR. -.Ip "\fB\-fugly-logint\fR" 4 -.IX Item "-fugly-logint" -Treat \f(CW\*(C`INTEGER\*(C'\fR and \f(CW\*(C`LOGICAL\*(C'\fR variables and -expressions as potential stand-ins for each other. -.Sp -For example, automatic conversion between \f(CW\*(C`INTEGER\*(C'\fR and -\&\f(CW\*(C`LOGICAL\*(C'\fR is enabled, for many contexts, via this option. -.Ip "\fB\-fonetrip\fR" 4 -.IX Item "-fonetrip" -Executable iterative \f(CW\*(C`DO\*(C'\fR loops are to be executed at -least once each time they are reached. -.Sp -\&\s-1ANSI\s0 \s-1FORTRAN\s0 77 and more recent versions of the Fortran standard -specify that the body of an iterative \f(CW\*(C`DO\*(C'\fR loop is not executed -if the number of iterations calculated from the parameters of the -loop is less than 1. -(For example, \fB\s-1DO\s0 10 I = 1, 0\fR.) -Such a loop is called a \fIzero-trip loop\fR. -.Sp -Prior to \s-1ANSI\s0 \s-1FORTRAN\s0 77, many compilers implemented \f(CW\*(C`DO\*(C'\fR loops -such that the body of a loop would be executed at least once, even -if the iteration count was zero. -Fortran code written assuming this behavior is said to require -\&\fIone-trip loops\fR. -For example, some code written to the \s-1FORTRAN\s0 66 standard -expects this behavior from its \f(CW\*(C`DO\*(C'\fR loops, although that -standard did not specify this behavior. -.Sp -The \fB\-fonetrip\fR option specifies that the source \fIfile\fR\|(s) being -compiled require one-trip loops. -.Sp -This option affects only those loops specified by the (iterative) \f(CW\*(C`DO\*(C'\fR -statement and by implied-\f(CW\*(C`DO\*(C'\fR lists in I/O statements. -Loops specified by implied-\f(CW\*(C`DO\*(C'\fR lists in \f(CW\*(C`DATA\*(C'\fR and -specification (non-executable) statements are not affected. -.Ip "\fB\-ftypeless-boz\fR" 4 -.IX Item "-ftypeless-boz" -Specifies that prefix-radix non-decimal constants, such as -\&\fBZ'\s-1ABCD\s0'\fR, are typeless instead of \f(CW\*(C`INTEGER(KIND=1)\*(C'\fR. -.Sp -You can test for yourself whether a particular compiler treats -the prefix form as \f(CW\*(C`INTEGER(KIND=1)\*(C'\fR or typeless by running the -following program: -.Sp -.Vb 6 -\& EQUIVALENCE (I, R) -\& R = Z'ABCD1234' -\& J = Z'ABCD1234' -\& IF (J .EQ. I) PRINT *, 'Prefix form is TYPELESS' -\& IF (J .NE. I) PRINT *, 'Prefix form is INTEGER' -\& END -.Ve -Reports indicate that many compilers process this form as -\&\f(CW\*(C`INTEGER(KIND=1)\*(C'\fR, though a few as typeless, and at least one -based on a command-line option specifying some kind of -compatibility. -.Ip "\fB\-fintrin-case-initcap\fR" 4 -.IX Item "-fintrin-case-initcap" -.PD 0 -.Ip "\fB\-fintrin-case-upper\fR" 4 -.IX Item "-fintrin-case-upper" -.Ip "\fB\-fintrin-case-lower\fR" 4 -.IX Item "-fintrin-case-lower" -.Ip "\fB\-fintrin-case-any\fR" 4 -.IX Item "-fintrin-case-any" -.PD -Specify expected case for intrinsic names. -\&\fB\-fintrin-case-lower\fR is the default. -.Ip "\fB\-fmatch-case-initcap\fR" 4 -.IX Item "-fmatch-case-initcap" -.PD 0 -.Ip "\fB\-fmatch-case-upper\fR" 4 -.IX Item "-fmatch-case-upper" -.Ip "\fB\-fmatch-case-lower\fR" 4 -.IX Item "-fmatch-case-lower" -.Ip "\fB\-fmatch-case-any\fR" 4 -.IX Item "-fmatch-case-any" -.PD -Specify expected case for keywords. -\&\fB\-fmatch-case-lower\fR is the default. -.Ip "\fB\-fsource-case-upper\fR" 4 -.IX Item "-fsource-case-upper" -.PD 0 -.Ip "\fB\-fsource-case-lower\fR" 4 -.IX Item "-fsource-case-lower" -.Ip "\fB\-fsource-case-preserve\fR" 4 -.IX Item "-fsource-case-preserve" -.PD -Specify whether source text other than character and Hollerith constants -is to be translated to uppercase, to lowercase, or preserved as is. -\&\fB\-fsource-case-lower\fR is the default. -.Ip "\fB\-fsymbol-case-initcap\fR" 4 -.IX Item "-fsymbol-case-initcap" -.PD 0 -.Ip "\fB\-fsymbol-case-upper\fR" 4 -.IX Item "-fsymbol-case-upper" -.Ip "\fB\-fsymbol-case-lower\fR" 4 -.IX Item "-fsymbol-case-lower" -.Ip "\fB\-fsymbol-case-any\fR" 4 -.IX Item "-fsymbol-case-any" -.PD -Specify valid cases for user-defined symbol names. -\&\fB\-fsymbol-case-any\fR is the default. -.Ip "\fB\-fcase-strict-upper\fR" 4 -.IX Item "-fcase-strict-upper" -Same as \fB\-fintrin-case-upper \-fmatch-case-upper \-fsource-case-preserve -\&\-fsymbol-case-upper\fR. -(Requires all pertinent source to be in uppercase.) -.Ip "\fB\-fcase-strict-lower\fR" 4 -.IX Item "-fcase-strict-lower" -Same as \fB\-fintrin-case-lower \-fmatch-case-lower \-fsource-case-preserve -\&\-fsymbol-case-lower\fR. -(Requires all pertinent source to be in lowercase.) -.Ip "\fB\-fcase-initcap\fR" 4 -.IX Item "-fcase-initcap" -Same as \fB\-fintrin-case-initcap \-fmatch-case-initcap \-fsource-case-preserve -\&\-fsymbol-case-initcap\fR. -(Requires all pertinent source to be in initial capitals, -as in \fBPrint *,SqRt(Value)\fR.) -.Ip "\fB\-fcase-upper\fR" 4 -.IX Item "-fcase-upper" -Same as \fB\-fintrin-case-any \-fmatch-case-any \-fsource-case-upper -\&\-fsymbol-case-any\fR. -(Maps all pertinent source to uppercase.) -.Ip "\fB\-fcase-lower\fR" 4 -.IX Item "-fcase-lower" -Same as \fB\-fintrin-case-any \-fmatch-case-any \-fsource-case-lower -\&\-fsymbol-case-any\fR. -(Maps all pertinent source to lowercase.) -.Ip "\fB\-fcase-preserve\fR" 4 -.IX Item "-fcase-preserve" -Same as \fB\-fintrin-case-any \-fmatch-case-any \-fsource-case-preserve -\&\-fsymbol-case-any\fR. -(Preserves all case in user-defined symbols, -while allowing any-case matching of intrinsics and keywords. -For example, \fBcall Foo(i,I)\fR would pass two \fIdifferent\fR -variables named \fBi\fR and \fBI\fR to a procedure named \fBFoo\fR.) -.Ip "\fB\-fbadu77\-intrinsics-delete\fR" 4 -.IX Item "-fbadu77-intrinsics-delete" -.PD 0 -.Ip "\fB\-fbadu77\-intrinsics-hide\fR" 4 -.IX Item "-fbadu77-intrinsics-hide" -.Ip "\fB\-fbadu77\-intrinsics-disable\fR" 4 -.IX Item "-fbadu77-intrinsics-disable" -.Ip "\fB\-fbadu77\-intrinsics-enable\fR" 4 -.IX Item "-fbadu77-intrinsics-enable" -.PD -Specify status of \s-1UNIX\s0 intrinsics having inappropriate forms. -\&\fB\-fbadu77\-intrinsics-enable\fR is the default. -.Ip "\fB\-ff2c-intrinsics-delete\fR" 4 -.IX Item "-ff2c-intrinsics-delete" -.PD 0 -.Ip "\fB\-ff2c-intrinsics-hide\fR" 4 -.IX Item "-ff2c-intrinsics-hide" -.Ip "\fB\-ff2c-intrinsics-disable\fR" 4 -.IX Item "-ff2c-intrinsics-disable" -.Ip "\fB\-ff2c-intrinsics-enable\fR" 4 -.IX Item "-ff2c-intrinsics-enable" -.PD -Specify status of f2c-specific intrinsics. -\&\fB\-ff2c-intrinsics-enable\fR is the default. -.Ip "\fB\-ff90\-intrinsics-delete\fR" 4 -.IX Item "-ff90-intrinsics-delete" -.PD 0 -.Ip "\fB\-ff90\-intrinsics-hide\fR" 4 -.IX Item "-ff90-intrinsics-hide" -.Ip "\fB\-ff90\-intrinsics-disable\fR" 4 -.IX Item "-ff90-intrinsics-disable" -.Ip "\fB\-ff90\-intrinsics-enable\fR" 4 -.IX Item "-ff90-intrinsics-enable" -.PD -Specify status of F90\-specific intrinsics. -\&\fB\-ff90\-intrinsics-enable\fR is the default. -.Ip "\fB\-fgnu-intrinsics-delete\fR" 4 -.IX Item "-fgnu-intrinsics-delete" -.PD 0 -.Ip "\fB\-fgnu-intrinsics-hide\fR" 4 -.IX Item "-fgnu-intrinsics-hide" -.Ip "\fB\-fgnu-intrinsics-disable\fR" 4 -.IX Item "-fgnu-intrinsics-disable" -.Ip "\fB\-fgnu-intrinsics-enable\fR" 4 -.IX Item "-fgnu-intrinsics-enable" -.PD -Specify status of Digital's COMPLEX-related intrinsics. -\&\fB\-fgnu-intrinsics-enable\fR is the default. -.Ip "\fB\-fmil-intrinsics-delete\fR" 4 -.IX Item "-fmil-intrinsics-delete" -.PD 0 -.Ip "\fB\-fmil-intrinsics-hide\fR" 4 -.IX Item "-fmil-intrinsics-hide" -.Ip "\fB\-fmil-intrinsics-disable\fR" 4 -.IX Item "-fmil-intrinsics-disable" -.Ip "\fB\-fmil-intrinsics-enable\fR" 4 -.IX Item "-fmil-intrinsics-enable" -.PD -Specify status of MIL-STD-1753\-specific intrinsics. -\&\fB\-fmil-intrinsics-enable\fR is the default. -.Ip "\fB\-funix-intrinsics-delete\fR" 4 -.IX Item "-funix-intrinsics-delete" -.PD 0 -.Ip "\fB\-funix-intrinsics-hide\fR" 4 -.IX Item "-funix-intrinsics-hide" -.Ip "\fB\-funix-intrinsics-disable\fR" 4 -.IX Item "-funix-intrinsics-disable" -.Ip "\fB\-funix-intrinsics-enable\fR" 4 -.IX Item "-funix-intrinsics-enable" -.PD -Specify status of \s-1UNIX\s0 intrinsics. -\&\fB\-funix-intrinsics-enable\fR is the default. -.Ip "\fB\-fvxt-intrinsics-delete\fR" 4 -.IX Item "-fvxt-intrinsics-delete" -.PD 0 -.Ip "\fB\-fvxt-intrinsics-hide\fR" 4 -.IX Item "-fvxt-intrinsics-hide" -.Ip "\fB\-fvxt-intrinsics-disable\fR" 4 -.IX Item "-fvxt-intrinsics-disable" -.Ip "\fB\-fvxt-intrinsics-enable\fR" 4 -.IX Item "-fvxt-intrinsics-enable" -.PD -Specify status of \s-1VXT\s0 intrinsics. -\&\fB\-fvxt-intrinsics-enable\fR is the default. -.Ip "\fB\-ffixed-line-length-\fR\fIn\fR" 4 -.IX Item "-ffixed-line-length-n" -Set column after which characters are ignored in typical fixed-form -lines in the source file, and through which spaces are assumed (as -if padded to that length) after the ends of short fixed-form lines. -.Sp -Popular values for \fIn\fR include 72 (the -standard and the default), 80 (card image), and 132 (corresponds -to ``extended-source'' options in some popular compilers). -\&\fIn\fR may be \fBnone\fR, meaning that the entire line is meaningful -and that continued character constants never have implicit spaces appended -to them to fill out the line. -\&\fB\-ffixed-line-length-0\fR means the same thing as -\&\fB\-ffixed-line-length-none\fR. -.Sh "Options to Request or Suppress Warnings" -.IX Subsection "Options to Request or Suppress Warnings" -Warnings are diagnostic messages that report constructions which -are not inherently erroneous but which are risky or suggest there -might have been an error. -.PP -You can request many specific warnings with options beginning \fB\-W\fR, -for example \fB\-Wimplicit\fR to request warnings on implicit -declarations. Each of these specific warning options also has a -negative form beginning \fB\-Wno-\fR to turn off warnings; -for example, \fB\-Wno-implicit\fR. This manual lists only one of the -two forms, whichever is not the default. -.PP -These options control the amount and kinds of warnings produced by \s-1GNU\s0 -Fortran: -.Ip "\fB\-fsyntax-only\fR" 4 -.IX Item "-fsyntax-only" -Check the code for syntax errors, but don't do anything beyond that. -.Ip "\fB\-pedantic\fR" 4 -.IX Item "-pedantic" -Issue warnings for uses of extensions to \s-1ANSI\s0 \s-1FORTRAN\s0 77. -\&\fB\-pedantic\fR also applies to C-language constructs where they -occur in \s-1GNU\s0 Fortran source files, such as use of \fB\ee\fR in a -character constant within a directive like \fB#include\fR. -.Sp -Valid \s-1ANSI\s0 \s-1FORTRAN\s0 77 programs should compile properly with or without -this option. -However, without this option, certain \s-1GNU\s0 extensions and traditional -Fortran features are supported as well. -With this option, many of them are rejected. -.Sp -Some users try to use \fB\-pedantic\fR to check programs for strict \s-1ANSI\s0 -conformance. -They soon find that it does not do quite what they want\-\-\-it finds some -non-ANSI practices, but not all. -However, improvements to \fBg77\fR in this area are welcome. -.Ip "\fB\-pedantic-errors\fR" 4 -.IX Item "-pedantic-errors" -Like \fB\-pedantic\fR, except that errors are produced rather than -warnings. -.Ip "\fB\-fpedantic\fR" 4 -.IX Item "-fpedantic" -Like \fB\-pedantic\fR, but applies only to Fortran constructs. -.Ip "\fB\-w\fR" 4 -.IX Item "-w" -Inhibit all warning messages. -.Ip "\fB\-Wno-globals\fR" 4 -.IX Item "-Wno-globals" -Inhibit warnings about use of a name as both a global name -(a subroutine, function, or block data program unit, or a -common block) and implicitly as the name of an intrinsic -in a source file. -.Sp -Also inhibit warnings about inconsistent invocations and/or -definitions of global procedures (function and subroutines). -Such inconsistencies include different numbers of arguments -and different types of arguments. -.Ip "\fB\-Wimplicit\fR" 4 -.IX Item "-Wimplicit" -Warn whenever a variable, array, or function is implicitly -declared. -Has an effect similar to using the \f(CW\*(C`IMPLICIT NONE\*(C'\fR statement -in every program unit. -(Some Fortran compilers provide this feature by an option -named \fB\-u\fR or \fB/WARNINGS=DECLARATIONS\fR.) -.Ip "\fB\-Wunused\fR" 4 -.IX Item "-Wunused" -Warn whenever a variable is unused aside from its declaration. -.Ip "\fB\-Wuninitialized\fR" 4 -.IX Item "-Wuninitialized" -Warn whenever an automatic variable is used without first being initialized. -.Sp -These warnings are possible only in optimizing compilation, -because they require data-flow information that is computed only -when optimizing. If you don't specify \fB\-O\fR, you simply won't -get these warnings. -.Sp -These warnings occur only for variables that are candidates for -register allocation. Therefore, they do not occur for a variable -whose address is taken, or whose size -is other than 1, 2, 4 or 8 bytes. Also, they do not occur for -arrays, even when they are in registers. -.Sp -Note that there might be no warning about a variable that is used only -to compute a value that itself is never used, because such -computations may be deleted by data-flow analysis before the warnings -are printed. -.Sp -These warnings are made optional because \s-1GNU\s0 Fortran is not smart -enough to see all the reasons why the code might be correct -despite appearing to have an error. Here is one example of how -this can happen: -.Sp -.Vb 6 -\& SUBROUTINE DISPAT(J) -\& IF (J.EQ.1) I=1 -\& IF (J.EQ.2) I=4 -\& IF (J.EQ.3) I=5 -\& CALL FOO(I) -\& END -.Ve -If the value of \f(CW\*(C`J\*(C'\fR is always 1, 2 or 3, then \f(CW\*(C`I\*(C'\fR is -always initialized, but \s-1GNU\s0 Fortran doesn't know this. Here is -another common case: -.Sp -.Vb 6 -\& SUBROUTINE MAYBE(FLAG) -\& LOGICAL FLAG -\& IF (FLAG) VALUE = 9.4 -\& ... -\& IF (FLAG) PRINT *, VALUE -\& END -.Ve -This has no bug because \f(CW\*(C`VALUE\*(C'\fR is used only if it is set. -.Ip "\fB\-Wall\fR" 4 -.IX Item "-Wall" -The \fB\-Wunused\fR and \fB\-Wuninitialized\fR options combined. -These are all the -options which pertain to usage that we recommend avoiding and that we -believe is easy to avoid. -(As more warnings are added to \fBg77\fR some might -be added to the list enabled by \fB\-Wall\fR.) -.PP -The remaining \fB\-W...\fR options are not implied by \fB\-Wall\fR -because they warn about constructions that we consider reasonable to -use, on occasion, in clean programs. -.Ip "\fB\-Wsurprising\fR" 4 -.IX Item "-Wsurprising" -Warn about ``suspicious'' constructs that are interpreted -by the compiler in a way that might well be surprising to -someone reading the code. -These differences can result in subtle, compiler-dependent -(even machine-dependent) behavioral differences. -The constructs warned about include: -.RS 4 -.Ip "\(bu" 4 -Expressions having two arithmetic operators in a row, such -as \fBX*\-Y\fR. -Such a construct is nonstandard, and can produce -unexpected results in more complicated situations such -as \fBX**\-Y*Z\fR. -\&\fBg77\fR along with many other compilers, interprets -this example differently than many programmers, and a few -other compilers. -Specifically, \fBg77\fR interprets \fBX**\-Y*Z\fR as -\&\fB(X**(\-Y))*Z\fR, while others might think it should -be interpreted as \fBX**(\-(Y*Z))\fR. -.Sp -A revealing example is the constant expression \fB2**\-2*1.\fR, -which \fBg77\fR evaluates to .25, while others might evaluate -it to 0., the difference resulting from the way precedence affects -type promotion. -.Sp -(The \fB\-fpedantic\fR option also warns about expressions -having two arithmetic operators in a row.) -.Ip "\(bu" 4 -Expressions with a unary minus followed by an operand and then -a binary operator other than plus or minus. -For example, \fB\-2**2\fR produces a warning, because -the precedence is \fB\-(2**2)\fR, yielding \-4, not -\&\fB(\-2)**2\fR, which yields 4, and which might represent -what a programmer expects. -.Sp -An example of an expression producing different results -in a surprising way is \fB\-I*S\fR, where \fII\fR holds -the value \fB\-2147483648\fR and \fIS\fR holds \fB0.5\fR. -On many systems, negating \fII\fR results in the same -value, not a positive number, because it is already the -lower bound of what an \f(CW\*(C`INTEGER(KIND=1)\*(C'\fR variable can hold. -So, the expression evaluates to a positive number, while -the ``expected'' interpretation, \fB(\-I)*S\fR, would -evaluate to a negative number. -.Sp -Even cases such as \fB\-I*J\fR produce warnings, -even though, in most configurations and situations, -there is no computational difference between the -results of the two interpretations\-\-\-the purpose -of this warning is to warn about differing interpretations -and encourage a better style of coding, not to identify -only those places where bugs might exist in the user's -code. -.Ip "\(bu" 4 -\&\f(CW\*(C`DO\*(C'\fR loops with \f(CW\*(C`DO\*(C'\fR variables that are not -of integral type\-\-\-that is, using \f(CW\*(C`REAL\*(C'\fR -variables as loop control variables. -Although such loops can be written to work in the -``obvious'' way, the way \fBg77\fR is required by the -Fortran standard to interpret such code is likely to -be quite different from the way many programmers expect. -(This is true of all \f(CW\*(C`DO\*(C'\fR loops, but the differences -are pronounced for non-integral loop control variables.) -.RE -.RS 4 -.RE -.Ip "\fB\-Werror\fR" 4 -.IX Item "-Werror" -Make all warnings into errors. -.Ip "\fB\-W\fR" 4 -.IX Item "-W" -Turns on ``extra warnings'' and, if optimization is specified -via \fB\-O\fR, the \fB\-Wuninitialized\fR option. -(This might change in future versions of \fBg77\fR -.Sp -``Extra warnings'' are issued for: -.RS 4 -.Ip "\(bu" 4 -Unused parameters to a procedure (when \fB\-Wunused\fR also is -specified). -.Ip "\(bu" 4 -Overflows involving floating-point constants (not available -for certain configurations). -.RE -.RS 4 -.RE -.PP -Some of these have no effect when compiling programs written in Fortran: -.Ip "\fB\-Wcomment\fR" 4 -.IX Item "-Wcomment" -.PD 0 -.Ip "\fB\-Wformat\fR" 4 -.IX Item "-Wformat" -.Ip "\fB\-Wparentheses\fR" 4 -.IX Item "-Wparentheses" -.Ip "\fB\-Wswitch\fR" 4 -.IX Item "-Wswitch" -.Ip "\fB\-Wtraditional\fR" 4 -.IX Item "-Wtraditional" -.Ip "\fB\-Wshadow\fR" 4 -.IX Item "-Wshadow" -.Ip "\fB\-Wid-clash-\fR\fIlen\fR" 4 -.IX Item "-Wid-clash-len" -.Ip "\fB\-Wlarger-than-\fR\fIlen\fR" 4 -.IX Item "-Wlarger-than-len" -.Ip "\fB\-Wconversion\fR" 4 -.IX Item "-Wconversion" -.Ip "\fB\-Waggregate-return\fR" 4 -.IX Item "-Waggregate-return" -.Ip "\fB\-Wredundant-decls\fR" 4 -.IX Item "-Wredundant-decls" -.PD -These options all could have some relevant meaning for -\&\s-1GNU\s0 Fortran programs, but are not yet supported. -.Sh "Options for Debugging Your Program or \s-1GNU\s0 Fortran" -.IX Subsection "Options for Debugging Your Program or GNU Fortran" -\&\s-1GNU\s0 Fortran has various special options that are used for debugging -either your program or \fBg77\fR -.Ip "\fB\-g\fR" 4 -.IX Item "-g" -Produce debugging information in the operating system's native format -(stabs, \s-1COFF\s0, \s-1XCOFF\s0, or \s-1DWARF\s0). \s-1GDB\s0 can work with this debugging -information. -.Sp -A sample debugging session looks like this (note the use of the breakpoint): -.Sp -.Vb 24 -\& $ cat gdb.f -\& PROGRAM PROG -\& DIMENSION A(10) -\& DATA A /1.,2.,3.,4.,5.,6.,7.,8.,9.,10./ -\& A(5) = 4. -\& PRINT*,A -\& END -\& $ g77 -g -O gdb.f -\& $ gdb a.out -\& ... -\& (gdb) break MAIN__ -\& Breakpoint 1 at 0x8048e96: file gdb.f, line 4. -\& (gdb) run -\& Starting program: /home/toon/g77-bugs/./a.out -\& Breakpoint 1, MAIN__ () at gdb.f:4 -\& 4 A(5) = 4. -\& Current language: auto; currently fortran -\& (gdb) print a(5) -\& $1 = 5 -\& (gdb) step -\& 5 PRINT*,A -\& (gdb) print a(5) -\& $2 = 4 -\& ... -.Ve -One could also add the setting of the breakpoint and the first run command -to the file \fI.gdbinit\fR in the current directory, to simplify the debugging -session. -.Sh "Options That Control Optimization" -.IX Subsection "Options That Control Optimization" -Most Fortran users will want to use no optimization when -developing and testing programs, and use \fB\-O\fR or \fB\-O2\fR when -compiling programs for late-cycle testing and for production use. -However, note that certain diagnostics\-\-\-such as for uninitialized -variables\-\-\-depend on the flow analysis done by \fB\-O\fR, i.e. you -must use \fB\-O\fR or \fB\-O2\fR to get such diagnostics. -.PP -The following flags have particular applicability when -compiling Fortran programs: -.Ip "\fB\-malign-double\fR" 4 -.IX Item "-malign-double" -(Intel x86 architecture only.) -.Sp -Noticeably improves performance of \fBg77\fR programs making -heavy use of \f(CW\*(C`REAL(KIND=2)\*(C'\fR (\f(CW\*(C`DOUBLE PRECISION\*(C'\fR) data -on some systems. -In particular, systems using Pentium, Pentium Pro, 586, and -686 implementations -of the i386 architecture execute programs faster when -\&\f(CW\*(C`REAL(KIND=2)\*(C'\fR (\f(CW\*(C`DOUBLE PRECISION\*(C'\fR) data are -aligned on 64\-bit boundaries -in memory. -.Sp -This option can, at least, make benchmark results more consistent -across various system configurations, versions of the program, -and data sets. -.Sp -\&\fINote:\fR The warning in the \fBgcc\fR documentation about -this option does not apply, generally speaking, to Fortran -code compiled by \fBg77\fR -.Sp -\&\fIAlso also note:\fR The negative form of \fB\-malign-double\fR -is \fB\-mno-align-double\fR, not \fB\-benign-double\fR. -.Ip "\fB\-ffloat-store\fR" 4 -.IX Item "-ffloat-store" -Might help a Fortran program that depends on exact \s-1IEEE\s0 conformance on -some machines, but might slow down a program that doesn't. -.Sp -This option is effective when the floating-point unit is set to work in -\&\s-1IEEE\s0 854 `extended precision'\-\-\-as it typically is on x86 and m68k \s-1GNU\s0 -systems\-\-\-rather than \s-1IEEE\s0 754 double precision. \fB\-ffloat-store\fR -tries to remove the extra precision by spilling data from floating-point -registers into memory and this typically involves a big performance -hit. However, it doesn't affect intermediate results, so that it is -only partially effective. `Excess precision' is avoided in code like: -.Sp -.Vb 2 -\& a = b + c -\& d = a * e -.Ve -but not in code like: -.Sp -.Vb 1 -\& d = (b + c) * e -.Ve -For another, potentially better, way of controlling the precision, -see \f(CW@ref\fR{Floating-point precision}. -.Ip "\fB\-fforce-mem\fR" 4 -.IX Item "-fforce-mem" -.PD 0 -.Ip "\fB\-fforce-addr\fR" 4 -.IX Item "-fforce-addr" -.PD -Might improve optimization of loops. -.Ip "\fB\-fno-inline\fR" 4 -.IX Item "-fno-inline" -Don't compile statement functions inline. -Might reduce the size of a program unit\-\-\-which might be at -expense of some speed (though it should compile faster). -Note that if you are not optimizing, no functions can be expanded inline. -.Ip "\fB\-ffast-math\fR" 4 -.IX Item "-ffast-math" -Might allow some programs designed to not be too dependent -on \s-1IEEE\s0 behavior for floating-point to run faster, or die trying. -Sets \fB\-funsafe-math-optimizations\fR, and -\&\fB\-fno-trapping-math\fR. -.Ip "\fB\-funsafe-math-optimizations\fR" 4 -.IX Item "-funsafe-math-optimizations" -Allow optimizations that may be give incorrect results -for certain \s-1IEEE\s0 inputs. -.Ip "\fB\-fno-trapping-math\fR" 4 -.IX Item "-fno-trapping-math" -Allow the compiler to assume that floating-point arithmetic -will not generate traps on any inputs. This is useful, for -example, when running a program using \s-1IEEE\s0 \*(L"non-stop\*(R" -floating-point arithmetic. -.Ip "\fB\-fstrength-reduce\fR" 4 -.IX Item "-fstrength-reduce" -Might make some loops run faster. -.Ip "\fB\-frerun-cse-after-loop\fR" 4 -.IX Item "-frerun-cse-after-loop" -.PD 0 -.Ip "\fB\-fexpensive-optimizations\fR" 4 -.IX Item "-fexpensive-optimizations" -.Ip "\fB\-fdelayed-branch\fR" 4 -.IX Item "-fdelayed-branch" -.Ip "\fB\-fschedule-insns\fR" 4 -.IX Item "-fschedule-insns" -.Ip "\fB\-fschedule-insns2\fR" 4 -.IX Item "-fschedule-insns2" -.Ip "\fB\-fcaller-saves\fR" 4 -.IX Item "-fcaller-saves" -.PD -Might improve performance on some code. -.Ip "\fB\-funroll-loops\fR" 4 -.IX Item "-funroll-loops" -Typically improves performance on code using iterative \f(CW\*(C`DO\*(C'\fR loops by -unrolling them and is probably generally appropriate for Fortran, though -it is not turned on at any optimization level. -Note that outer loop unrolling isn't done specifically; decisions about -whether to unroll a loop are made on the basis of its instruction count. -.Sp -Also, no `loop discovery'[1] is done, so only loops written with \f(CW\*(C`DO\*(C'\fR -benefit from loop optimizations, including\-\-\-but not limited -to\-\-\-unrolling. Loops written with \f(CW\*(C`IF\*(C'\fR and \f(CW\*(C`GOTO\*(C'\fR are not -currently recognized as such. This option unrolls only iterative -\&\f(CW\*(C`DO\*(C'\fR loops, not \f(CW\*(C`DO WHILE\*(C'\fR loops. -.Ip "\fB\-funroll-all-loops\fR" 4 -.IX Item "-funroll-all-loops" -Probably improves performance on code using \f(CW\*(C`DO WHILE\*(C'\fR loops by -unrolling them in addition to iterative \f(CW\*(C`DO\*(C'\fR loops. In the absence -of \f(CW\*(C`DO WHILE\*(C'\fR, this option is equivalent to \fB\-funroll-loops\fR -but possibly slower. -.Ip "\fB\-fno-move-all-movables\fR" 4 -.IX Item "-fno-move-all-movables" -.PD 0 -.Ip "\fB\-fno-reduce-all-givs\fR" 4 -.IX Item "-fno-reduce-all-givs" -.Ip "\fB\-fno-rerun-loop-opt\fR" 4 -.IX Item "-fno-rerun-loop-opt" -.PD -In general, the optimizations enabled with these options will lead to -faster code being generated by \s-1GNU\s0 Fortran; hence they are enabled by default -when issuing the \fBg77\fR command. -.Sp -\&\fB\-fmove-all-movables\fR and \fB\-freduce-all-givs\fR will enable -loop optimization to move all loop-invariant index computations in nested -loops over multi-rank array dummy arguments out of these loops. -.Sp -\&\fB\-frerun-loop-opt\fR will move offset calculations resulting -from the fact that Fortran arrays by default have a lower bound of 1 -out of the loops. -.Sp -These three options are intended to be removed someday, once -loop optimization is sufficiently advanced to perform all those -transformations without help from these options. -.Sh "Options Controlling the Preprocessor" -.IX Subsection "Options Controlling the Preprocessor" -These options control the C preprocessor, which is run on each C source -file before actual compilation. -.PP -Some of these options also affect how \fBg77\fR processes the -\&\f(CW\*(C`INCLUDE\*(C'\fR directive. -Since this directive is processed even when preprocessing -is not requested, it is not described in this section. -.PP -However, the \f(CW\*(C`INCLUDE\*(C'\fR directive does not apply -preprocessing to the contents of the included file itself. -.PP -Therefore, any file that contains preprocessor directives -(such as \f(CW\*(C`#include\*(C'\fR, \f(CW\*(C`#define\*(C'\fR, and \f(CW\*(C`#if\*(C'\fR) -must be included via the \f(CW\*(C`#include\*(C'\fR directive, not -via the \f(CW\*(C`INCLUDE\*(C'\fR directive. -Therefore, any file containing preprocessor directives, -if included, is necessarily included by a file that itself -contains preprocessor directives. -.Sh "Options for Directory Search" -.IX Subsection "Options for Directory Search" -These options affect how the \fBcpp\fR preprocessor searches -for files specified via the \f(CW\*(C`#include\*(C'\fR directive. -Therefore, when compiling Fortran programs, they are meaningful -when the preprocessor is used. -.PP -Some of these options also affect how \fBg77\fR searches -for files specified via the \f(CW\*(C`INCLUDE\*(C'\fR directive, -although files included by that directive are not, -themselves, preprocessed. -These options are: -.Ip "\fB\-I-\fR" 4 -.IX Item "-I-" -.PD 0 -.Ip "\fB\-I\fR\fIdir\fR" 4 -.IX Item "-Idir" -.PD -These affect interpretation of the \f(CW\*(C`INCLUDE\*(C'\fR directive -(as well as of the \f(CW\*(C`#include\*(C'\fR directive of the \fBcpp\fR -preprocessor). -.Sp -Note that \fB\-I\fR\fIdir\fR must be specified \fIwithout\fR any -spaces between \fB\-I\fR and the directory name\-\-\-that is, -\&\fB\-Ifoo/bar\fR is valid, but \fB\-I foo/bar\fR -is rejected by the \fBg77\fR compiler (though the preprocessor supports -the latter form). -Also note that the general behavior of \fB\-I\fR and -\&\f(CW\*(C`INCLUDE\*(C'\fR is pretty much the same as of \fB\-I\fR with -\&\f(CW\*(C`#include\*(C'\fR in the \fBcpp\fR preprocessor, with regard to -looking for \fIheader.gcc\fR files and other such things. -.Sh "Options for Code Generation Conventions" -.IX Subsection "Options for Code Generation Conventions" -These machine-independent options control the interface conventions -used in code generation. -.PP -Most of them have both positive and negative forms; the negative form -of \fB\-ffoo\fR would be \fB\-fno-foo\fR. In the table below, only -one of the forms is listed\-\-\-the one which is not the default. You -can figure out the other form by either removing \fBno-\fR or adding -it. -.Ip "\fB\-fno-automatic\fR" 4 -.IX Item "-fno-automatic" -Treat each program unit as if the \f(CW\*(C`SAVE\*(C'\fR statement was specified -for every local variable and array referenced in it. -Does not affect common blocks. -(Some Fortran compilers provide this option under -the name \fB\-static\fR.) -.Ip "\fB\-finit-local-zero\fR" 4 -.IX Item "-finit-local-zero" -Specify that variables and arrays that are local to a program unit -(not in a common block and not passed as an argument) are to be initialized -to binary zeros. -.Sp -Since there is a run-time penalty for initialization of variables -that are not given the \f(CW\*(C`SAVE\*(C'\fR attribute, it might be a -good idea to also use \fB\-fno-automatic\fR with \fB\-finit-local-zero\fR. -.Ip "\fB\-fno-f2c\fR" 4 -.IX Item "-fno-f2c" -Do not generate code designed to be compatible with code generated -by \fBf2c\fR use the \s-1GNU\s0 calling conventions instead. -.Sp -The \fBf2c\fR calling conventions require functions that return -type \f(CW\*(C`REAL(KIND=1)\*(C'\fR to actually return the C type \f(CW\*(C`double\*(C'\fR, -and functions that return type \f(CW\*(C`COMPLEX\*(C'\fR to return the -values via an extra argument in the calling sequence that points -to where to store the return value. -Under the \s-1GNU\s0 calling conventions, such functions simply return -their results as they would in \s-1GNU\s0 C\-\--\f(CW\*(C`REAL(KIND=1)\*(C'\fR functions -return the C type \f(CW\*(C`float\*(C'\fR, and \f(CW\*(C`COMPLEX\*(C'\fR functions -return the \s-1GNU\s0 C type \f(CW\*(C`complex\*(C'\fR (or its \f(CW\*(C`struct\*(C'\fR -equivalent). -.Sp -This does not affect the generation of code that interfaces with the -\&\f(CW\*(C`libg2c\*(C'\fR library. -.Sp -However, because the \f(CW\*(C`libg2c\*(C'\fR library uses \fBf2c\fR -calling conventions, \fBg77\fR rejects attempts to pass -intrinsics implemented by routines in this library as actual -arguments when \fB\-fno-f2c\fR is used, to avoid bugs when -they are actually called by code expecting the \s-1GNU\s0 calling -conventions to work. -.Sp -For example, \fB\s-1INTRINSIC\s0 \s-1ABS\s0;CALL FOO(\s-1ABS\s0)\fR is -rejected when \fB\-fno-f2c\fR is in force. -(Future versions of the \fBg77\fR run-time library might -offer routines that provide GNU-callable versions of the -routines that implement the \fBf2c\fR intrinsics -that may be passed as actual arguments, so that -valid programs need not be rejected when \fB\-fno-f2c\fR -is used.) -.Sp -\&\fBCaution:\fR If \fB\-fno-f2c\fR is used when compiling any -source file used in a program, it must be used when compiling -\&\fIall\fR Fortran source files used in that program. -.Ip "\fB\-ff2c-library\fR" 4 -.IX Item "-ff2c-library" -Specify that use of \f(CW\*(C`libg2c\*(C'\fR (or the original \f(CW\*(C`libf2c\*(C'\fR) -is required. -This is the default for the current version of \fBg77\fR -.Sp -Currently it is not -valid to specify \fB\-fno-f2c-library\fR. -This option is provided so users can specify it in shell -scripts that build programs and libraries that require the -\&\f(CW\*(C`libf2c\*(C'\fR library, even when being compiled by future -versions of \fBg77\fR that might otherwise default to -generating code for an incompatible library. -.Ip "\fB\-fno-underscoring\fR" 4 -.IX Item "-fno-underscoring" -Do not transform names of entities specified in the Fortran -source file by appending underscores to them. -.Sp -With \fB\-funderscoring\fR in effect, \fBg77\fR appends two underscores -to names with underscores and one underscore to external names with -no underscores. (\fBg77\fR also appends two underscores to internal -names with underscores to avoid naming collisions with external names. -The \fB\-fno-second-underscore\fR option disables appending of the -second underscore in all cases.) -.Sp -This is done to ensure compatibility with code produced by many -\&\s-1UNIX\s0 Fortran compilers, including \fBf2c\fR which perform the -same transformations. -.Sp -Use of \fB\-fno-underscoring\fR is not recommended unless you are -experimenting with issues such as integration of (\s-1GNU\s0) Fortran into -existing system environments (vis-a-vis existing libraries, tools, and -so on). -.Sp -For example, with \fB\-funderscoring\fR, and assuming other defaults like -\&\fB\-fcase-lower\fR and that \fB\f(BIj()\fB\fR and \fB\f(BImax_count()\fB\fR are -external functions while \fBmy_var\fR and \fBlvar\fR are local variables, -a statement like -.Sp -.Vb 1 -\& I = J() + MAX_COUNT (MY_VAR, LVAR) -.Ve -is implemented as something akin to: -.Sp -.Vb 1 -\& i = j_() + max_count__(&my_var__, &lvar); -.Ve -With \fB\-fno-underscoring\fR, the same statement is implemented as: -.Sp -.Vb 1 -\& i = j() + max_count(&my_var, &lvar); -.Ve -Use of \fB\-fno-underscoring\fR allows direct specification of -user-defined names while debugging and when interfacing \fBg77\fR -code with other languages. -.Sp -Note that just because the names match does \fInot\fR mean that the -interface implemented by \fBg77\fR for an external name matches the -interface implemented by some other language for that same name. -That is, getting code produced by \fBg77\fR to link to code produced -by some other compiler using this or any other method can be only a -small part of the overall solution\-\-\-getting the code generated by -both compilers to agree on issues other than naming can require -significant effort, and, unlike naming disagreements, linkers normally -cannot detect disagreements in these other areas. -.Sp -Also, note that with \fB\-fno-underscoring\fR, the lack of appended -underscores introduces the very real possibility that a user-defined -external name will conflict with a name in a system library, which -could make finding unresolved-reference bugs quite difficult in some -cases\-\-\-they might occur at program run time, and show up only as -buggy behavior at run time. -.Sp -In future versions of \fBg77\fR we hope to improve naming and linking -issues so that debugging always involves using the names as they appear -in the source, even if the names as seen by the linker are mangled to -prevent accidental linking between procedures with incompatible -interfaces. -.Ip "\fB\-fno-second-underscore\fR" 4 -.IX Item "-fno-second-underscore" -Do not append a second underscore to names of entities specified -in the Fortran source file. -.Sp -This option has no effect if \fB\-fno-underscoring\fR is -in effect. -.Sp -Otherwise, with this option, an external name such as \fB\s-1MAX_COUNT\s0\fR -is implemented as a reference to the link-time external symbol -\&\fBmax_count_\fR, instead of \fBmax_count_\|_\fR. -.Ip "\fB\-fno-ident\fR" 4 -.IX Item "-fno-ident" -Ignore the \fB#ident\fR directive. -.Ip "\fB\-fzeros\fR" 4 -.IX Item "-fzeros" -Treat initial values of zero as if they were any other value. -.Sp -As of version 0.5.18, \fBg77\fR normally treats \f(CW\*(C`DATA\*(C'\fR and -other statements that are used to specify initial values of zero -for variables and arrays as if no values were actually specified, -in the sense that no diagnostics regarding multiple initializations -are produced. -.Sp -This is done to speed up compiling of programs that initialize -large arrays to zeros. -.Sp -Use \fB\-fzeros\fR to revert to the simpler, slower behavior -that can catch multiple initializations by keeping track of -all initializations, zero or otherwise. -.Sp -\&\fICaution:\fR Future versions of \fBg77\fR might disregard this option -(and its negative form, the default) or interpret it somewhat -differently. -The interpretation changes will affect only non-standard -programs; standard-conforming programs should not be affected. -.Ip "\fB\-femulate-complex\fR" 4 -.IX Item "-femulate-complex" -Implement \f(CW\*(C`COMPLEX\*(C'\fR arithmetic via emulation, -instead of using the facilities of -the \fBgcc\fR back end that provide direct support of -\&\f(CW\*(C`complex\*(C'\fR arithmetic. -.Sp -(\fBgcc\fR had some bugs in its back-end support -for \f(CW\*(C`complex\*(C'\fR arithmetic, due primarily to the support not being -completed as of version 2.8.1 and \f(CW\*(C`egcs\*(C'\fR 1.1.2.) -.Sp -Use \fB\-femulate-complex\fR if you suspect code-generation bugs, -or experience compiler crashes, -that might result from \fBg77\fR using the \f(CW\*(C`COMPLEX\*(C'\fR support -in the \fBgcc\fR back end. -If using that option fixes the bugs or crashes you are seeing, -that indicates a likely \fBg77\fR bugs -(though, all compiler crashes are considered bugs), -so, please report it. -(Note that the known bugs, now believed fixed, produced compiler crashes -rather than causing the generation of incorrect code.) -.Sp -Use of this option should not affect how Fortran code compiled -by \fBg77\fR works in terms of its interfaces to other code, -e.g. that compiled by \fBf2c\fR -.Sp -As of \s-1GCC\s0 version 3.0, this option is not necessary anymore. -.Sp -\&\fICaution:\fR Future versions of \fBg77\fR might ignore both forms -of this option. -.Ip "\fB\-falias-check\fR" 4 -.IX Item "-falias-check" -.PD 0 -.Ip "\fB\-fargument-alias\fR" 4 -.IX Item "-fargument-alias" -.Ip "\fB\-fargument-noalias\fR" 4 -.IX Item "-fargument-noalias" -.Ip "\fB\-fno-argument-noalias-global\fR" 4 -.IX Item "-fno-argument-noalias-global" -.PD -\&\fIVersion info:\fR -These options are not supported by -versions of \fBg77\fR based on \fBgcc\fR version 2.8. -.Sp -These options specify to what degree aliasing -(overlap) -is permitted between -arguments (passed as pointers) and \f(CW\*(C`COMMON\*(C'\fR (external, or -public) storage. -.Sp -The default for Fortran code, as mandated by the \s-1FORTRAN\s0 77 and -Fortran 90 standards, is \fB\-fargument-noalias-global\fR. -The default for code written in the C language family is -\&\fB\-fargument-alias\fR. -.Sp -Note that, on some systems, compiling with \fB\-fforce-addr\fR in -effect can produce more optimal code when the default aliasing -options are in effect (and when optimization is enabled). -.Ip "\fB\-fno-globals\fR" 4 -.IX Item "-fno-globals" -Disable diagnostics about inter-procedural -analysis problems, such as disagreements about the -type of a function or a procedure's argument, -that might cause a compiler crash when attempting -to inline a reference to a procedure within a -program unit. -(The diagnostics themselves are still produced, but -as warnings, unless \fB\-Wno-globals\fR is specified, -in which case no relevant diagnostics are produced.) -.Sp -Further, this option disables such inlining, to -avoid compiler crashes resulting from incorrect -code that would otherwise be diagnosed. -.Sp -As such, this option might be quite useful when -compiling existing, ``working'' code that happens -to have a few bugs that do not generally show themselves, -but which \fBg77\fR diagnoses. -.Sp -Use of this option therefore has the effect of -instructing \fBg77\fR to behave more like it did -up through version 0.5.19.1, when it paid little or -no attention to disagreements between program units -about a procedure's type and argument information, -and when it performed no inlining of procedures -(except statement functions). -.Sp -Without this option, \fBg77\fR defaults to performing -the potentially inlining procedures as it started doing -in version 0.5.20, but as of version 0.5.21, it also -diagnoses disagreements that might cause such inlining -to crash the compiler as (fatal) errors, -and warns about similar disagreements -that are currently believed to not -likely to result in the compiler later crashing -or producing incorrect code. -.Ip "\fB\-fflatten-arrays\fR" 4 -.IX Item "-fflatten-arrays" -Use back end's C-like constructs -(pointer plus offset) -instead of its \f(CW\*(C`ARRAY_REF\*(C'\fR construct -to handle all array references. -.Sp -\&\fINote:\fR This option is not supported. -It is intended for use only by \fBg77\fR developers, -to evaluate code-generation issues. -It might be removed at any time. -.Ip "\fB\-fbounds-check\fR" 4 -.IX Item "-fbounds-check" -.PD 0 -.Ip "\fB\-ffortran-bounds-check\fR" 4 -.IX Item "-ffortran-bounds-check" -.PD -Enable generation of run-time checks for array subscripts -and substring start and end points -against the (locally) declared minimum and maximum values. -.Sp -The current implementation uses the \f(CW\*(C`libf2c\*(C'\fR -library routine \f(CW\*(C`s_rnge\*(C'\fR to print the diagnostic. -.Sp -However, whereas \fBf2c\fR generates a single check per -reference for a multi-dimensional array, of the computed -offset against the valid offset range (0 through the size of the array), -\&\fBg77\fR generates a single check per \fIsubscript\fR expression. -This catches some cases of potential bugs that \fBf2c\fR does not, -such as references to below the beginning of an assumed-size array. -.Sp -\&\fBg77\fR also generates checks for \f(CW\*(C`CHARACTER\*(C'\fR substring references, -something \fBf2c\fR currently does not do. -.Sp -Use the new \fB\-ffortran-bounds-check\fR option -to specify bounds-checking for only the Fortran code you are compiling, -not necessarily for code written in other languages. -.Sp -\&\fINote:\fR To provide more detailed information on the offending subscript, -\&\fBg77\fR provides the \f(CW\*(C`libg2c\*(C'\fR run-time library routine \f(CW\*(C`s_rnge\*(C'\fR -with somewhat differently-formatted information. -Here's a sample diagnostic: -.Sp -.Vb 3 -\& Subscript out of range on file line 4, procedure rnge.f/bf. -\& Attempt to access the -6-th element of variable b[subscript-2-of-2]. -\& Aborted -.Ve -The above message indicates that the offending source line is -line 4 of the file \fIrnge.f\fR, -within the program unit (or statement function) named \fBbf\fR. -The offended array is named \fBb\fR. -The offended array dimension is the second for a two-dimensional array, -and the offending, computed subscript expression was \fB\-6\fR. -.Sp -For a \f(CW\*(C`CHARACTER\*(C'\fR substring reference, the second line has -this appearance: -.Sp -.Vb 1 -\& Attempt to access the 11-th element of variable a[start-substring]. -.Ve -This indicates that the offended \f(CW\*(C`CHARACTER\*(C'\fR variable or array -is named \fBa\fR, -the offended substring position is the starting (leftmost) position, -and the offending substring expression is \fB11\fR. -.Sp -(Though the verbage of \f(CW\*(C`s_rnge\*(C'\fR is not ideal -for the purpose of the \fBg77\fR compiler, -the above information should provide adequate diagnostic abilities -to it users.) -.PP -Some of these do \fInot\fR work when compiling programs written in Fortran: -.Ip "\fB\-fpcc-struct-return\fR" 4 -.IX Item "-fpcc-struct-return" -.PD 0 -.Ip "\fB\-freg-struct-return\fR" 4 -.IX Item "-freg-struct-return" -.PD -You should not use these except strictly the same way as you -used them to build the version of \f(CW\*(C`libg2c\*(C'\fR with which -you will be linking all code compiled by \fBg77\fR with the -same option. -.Ip "\fB\-fshort-double\fR" 4 -.IX Item "-fshort-double" -This probably either has no effect on Fortran programs, or -makes them act loopy. -.Ip "\fB\-fno-common\fR" 4 -.IX Item "-fno-common" -Do not use this when compiling Fortran programs, -or there will be Trouble. -.Ip "\fB\-fpack-struct\fR" 4 -.IX Item "-fpack-struct" -This probably will break any calls to the \f(CW\*(C`libg2c\*(C'\fR library, -at the very least, even if it is built with the same option. -.SH "ENVIRONMENT" -.IX Header "ENVIRONMENT" -\&\s-1GNU\s0 Fortran currently does not make use of any environment -variables to control its operation above and beyond those -that affect the operation of \fBgcc\fR. -.SH "BUGS" -.IX Header "BUGS" -For instructions on reporting bugs, see -<\fBhttp://gcc.gnu.org/bugs.html\fR>. Use of the \fBgccbug\fR -script to report bugs is recommended. -.SH "FOOTNOTES" -.IX Header "FOOTNOTES" -.Ip "1." 4 -\&\fIloop discovery\fR refers to the -process by which a compiler, or indeed any reader of a program, -determines which portions of the program are more likely to be executed -repeatedly as it is being run. Such discovery typically is done early -when compiling using optimization techniques, so the ``discovered'' -loops get more attention\-\-\-and more run-time resources, such as -registers\-\-\-from the compiler. It is easy to ``discover'' loops that are -constructed out of looping constructs in the language -(such as Fortran's \f(CW\*(C`DO\*(C'\fR). For some programs, ``discovering'' loops -constructed out of lower-level constructs (such as \f(CW\*(C`IF\*(C'\fR and -\&\f(CW\*(C`GOTO\*(C'\fR) can lead to generation of more optimal code -than otherwise. -.SH "SEE ALSO" -.IX Header "SEE ALSO" -\&\fIgpl\fR\|(7), \fIgfdl\fR\|(7), \fIfsf-funding\fR\|(7), -\&\fIcpp\fR\|(1), \fIgcov\fR\|(1), \fIgcc\fR\|(1), \fIas\fR\|(1), \fIld\fR\|(1), \fIgdb\fR\|(1), \fIadb\fR\|(1), \fIdbx\fR\|(1), \fIsdb\fR\|(1) -and the Info entries for \fIgcc\fR, \fIcpp\fR, \fIg77\fR, \fIas\fR, -\&\fIld\fR, \fIbinutils\fR and \fIgdb\fR. -.SH "AUTHOR" -.IX Header "AUTHOR" -See the Info entry for \fBg77\fR for contributors to \s-1GCC\s0 and G77. -.SH "COPYRIGHT" -.IX Header "COPYRIGHT" -Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002 -Free Software Foundation, Inc. -.PP -Permission is granted to copy, distribute and/or modify this document -under the terms of the \s-1GNU\s0 Free Documentation License, Version 1.1 or -any later version published by the Free Software Foundation; with the -Invariant Sections being ``\s-1GNU\s0 General Public License'' and ``Funding -Free Software'', the Front-Cover texts being (a) (see below), and with -the Back-Cover Texts being (b) (see below). A copy of the license is -included in the \fIgfdl\fR\|(7) man page. -.PP -(a) The \s-1FSF\s0's Front-Cover Text is: -.PP -.Vb 1 -\& A GNU Manual -.Ve -(b) The \s-1FSF\s0's Back-Cover Text is: -.PP -.Vb 3 -\& You have freedom to copy and modify this GNU Manual, like GNU -\& software. Copies published by the Free Software Foundation raise -\& funds for GNU development. -.Ve diff --git a/contrib/gcc/gcc.1 b/contrib/gcc/gcc.1 deleted file mode 100644 index 74200a1a169e..000000000000 --- a/contrib/gcc/gcc.1 +++ /dev/null @@ -1,4191 +0,0 @@ -.\" Copyright (c) 1991, 1992, 1993, 1994 Free Software Foundation -*-Text-*- -.\" See section COPYING for conditions for redistribution -.\" -.\" Set up \*(lq, \*(rq if -man hasn't already set it up. -.if @@\*(lq@ \{\ -. ds lq " -. if t .ds lq `` -. if !@@\(lq@ .ds lq "\(lq -.\} -.if @@\*(rq@ \{\ -. ds rq " -. if t .ds rq '' -. if !@@\(rq@ .ds rq "\(rq -.\} -.de Id -.ds Rv \\$3 -.ds Dt \\$4 -.. -.de Sp -.if n .sp -.if t .sp 0.4 -.. -.Id $Id: gcc.1,v 1.9 1998/12/16 20:55:57 law Exp $ -.TH GCC 1 "\*(Dt" "GNU Tools" "GNU Tools" -.SH NAME -gcc, g++ \- GNU project C and C++ Compiler (gcc-2.95) -.SH SYNOPSIS -.B gcc -.RI "[ " option " | " filename " ].\|.\|." -.br -.B g++ -.RI "[ " option " | " filename " ].\|.\|." -.SH WARNING -The information in this man page is an extract from the full -documentation of the GNU C compiler, and is limited to the meaning of -the options. -.PP -This man page is not kept up to date except when volunteers want to -maintain it. If you find a discrepancy between the man page and the -software, please check the Info file, which is the authoritative -documentation. -.PP -If we find that the things in this man page that are out of date cause -significant confusion or complaints, we will stop distributing the man -page. The alternative, updating the man page when we update the Info -file, is impossible because the rest of the work of maintaining GNU CC -leaves us no time for that. The GNU project regards man pages as -obsolete and should not let them take time away from other things. -.PP -For complete and current documentation, refer to the Info file `\|\c -.B gcc\c -\&\|' or the manual -.I -Using and Porting GNU CC (for version 2.0)\c -\&. Both are made from the Texinfo source file -.BR gcc.texinfo . -.SH DESCRIPTION -The C and C++ compilers are integrated. Both process input files -through one or more of four stages: preprocessing, compilation, -assembly, and linking. Source filename suffixes identify the source -language, but which name you use for the compiler governs default -assumptions: -.TP -.B gcc -assumes preprocessed (\c -.B .i\c -\&) files are C and assumes C style linking. -.TP -.B g++ -assumes preprocessed (\c -.B .i\c -\&) files are C++ and assumes C++ style linking. -.PP -Suffixes of source file names indicate the language and kind of -processing to be done: -.Sp -.nf -.ta \w'\fB.cxx\fP 'u -\&\fB.c\fP C source; preprocess, compile, assemble -\&\fB.C\fP C++ source; preprocess, compile, assemble -\&\fB.cc\fP C++ source; preprocess, compile, assemble -\&\fB.cxx\fP C++ source; preprocess, compile, assemble -\&\fB.m\fP Objective-C source; preprocess, compile, assemble -\&\fB.i\fP preprocessed C; compile, assemble -\&\fB.ii\fP preprocessed C++; compile, assemble -\&\fB.s\fP Assembler source; assemble -\&\fB.S\fP Assembler source; preprocess, assemble -\&\fB.h\fP Preprocessor file; not usually named on command line -.Sp -.fi -Files with other suffixes are passed to the linker. Common cases include: -.Sp -.nf -\&\fB.o\fP Object file -\&\fB.a\fP Archive file -.br -.fi -.Sp -Linking is always the last stage unless you use one of the -.BR \-c , -.BR \-S , -or -.B \-E -options to avoid it (or unless compilation errors stop the whole -process). For the link stage, all -.B .o -files corresponding to source files, -.B \-l -libraries, unrecognized filenames (including named -.B .o -object files and -.B .a -archives) -are passed to the linker in command-line order. -.SH OPTIONS -Options must be separate: `\|\c -.B \-dr\c -\&\|' is quite different from `\|\c -.B \-d \-r -\&\|'. -.PP -Most `\|\c -.B \-f\c -\&\|' and `\|\c -.B \-W\c -\&\|' options have two contrary forms: -.BI \-f name -and -.BI \-fno\- name\c -\& (or -.BI \-W name -and -.BI \-Wno\- name\c -\&). Only the non-default forms are shown here. -.PP -Here is a summary of all the options, grouped by type. Explanations are -in the following sections. -.hy 0 -.na -.TP -.B Overall Options -.br -\-c -\-S -\-E -.RI "\-o " file -\-pipe -\-v -.RI "\-x " language -.TP -.B Language Options -\-ansi -\-fall\-virtual -\-fcond\-mismatch -\-fdollars\-in\-identifiers -\-fenum\-int\-equiv -\-fexternal\-templates -\-fno\-asm -\-fno\-builtin -\-fhosted -\-fno\-hosted -\-ffreestanding -\-fno\-freestanding -\-fno\-strict\-prototype -\-fsigned\-bitfields -\-fsigned\-char -\-fthis\-is\-variable -\-funsigned\-bitfields -\-funsigned\-char -\-fwritable\-strings -\-traditional -\-traditional\-cpp -\-trigraphs -.TP -.B Warning Options -\-fsyntax\-only -\-pedantic -\-pedantic\-errors -\-w -\-W -\-Wall -\-Waggregate\-return -\-Wcast\-align -\-Wcast\-qual -\-Wchar\-subscript -\-Wcomment -\-Wconversion -\-Wenum\-clash -\-Werror -\-Wformat -.RI \-Wid\-clash\- len -\-Wimplicit -\-Wimplicit\-int -\-Wimplicit\-function\-declaration -\-Winline -\-Wlong\-long -\-Wmain -\-Wmissing\-prototypes -\-Wmissing\-declarations -\-Wnested\-externs -\-Wno\-import -\-Wparentheses -\-Wpointer\-arith -\-Wredundant\-decls -\-Wreturn\-type -\-Wshadow -\-Wstrict\-prototypes -\-Wswitch -\-Wtemplate\-debugging -\-Wtraditional -\-Wtrigraphs -\-Wuninitialized -\-Wunused -\-Wwrite\-strings -.TP -.B Debugging Options -\-a -.RI \-d letters -\-fpretend\-float -\-g -.RI \-g level -\-gcoff -\-gxcoff -\-gxcoff+ -\-gdwarf -\-gdwarf+ -\-gstabs -\-gstabs+ -\-ggdb -\-p -\-pg -\-save\-temps -.RI \-print\-file\-name= library -\-print\-libgcc\-file\-name -.RI \-print\-prog\-name= program -.TP -.B Optimization Options -\-fcaller\-saves -\-fcse\-follow\-jumps -\-fcse\-skip\-blocks -\-fdelayed\-branch -\-felide\-constructors -\-fexpensive\-optimizations -\-ffast\-math -\-ffloat\-store -\-fforce\-addr -\-fforce\-mem -\-finline\-functions -\-fkeep\-inline\-functions -\-fmemoize\-lookups -\-fno\-default\-inline -\-fno\-defer\-pop -\-fno\-function\-cse -\-fno\-inline -\-fno\-peephole -\-fomit\-frame\-pointer -\-frerun\-cse\-after\-loop -\-fschedule\-insns -\-fschedule\-insns2 -\-fstrength\-reduce -\-fthread\-jumps -\-funroll\-all\-loops -\-funroll\-loops -\-O -\-O2 -\-O3 -.TP -.B Preprocessor Options -.RI \-A assertion -\-C -\-dD -\-dM -\-dN -.RI \-D macro [\|= defn \|] -\-E -\-H -.RI "\-idirafter " dir -.RI "\-include " file -.RI "\-imacros " file -.RI "\-iprefix " file -.RI "\-iwithprefix " dir -\-M -\-MD -\-MM -\-MMD -\-nostdinc -\-P -.RI \-U macro -\-undef -.TP -.B Assembler Option -.RI \-Wa, option -.TP -.B Linker Options -.RI \-l library -\-nostartfiles -\-nostdlib -\-static -\-shared -\-symbolic -.RI "\-Xlinker\ " option -.RI \-Wl, option -.RI "\-u " symbol -.TP -.B Directory Options -.RI \-B prefix -.RI \-I dir -\-I\- -.RI \-L dir -.TP -.B Target Options -.RI "\-b " machine -.RI "\-V " version -.TP -.B Configuration Dependent Options -.I M680x0\ Options -.br -\-m68000 -\-m68020 -\-m68020\-40 -\-m68030 -\-m68040 -\-m68881 -\-mbitfield -\-mc68000 -\-mc68020 -\-mfpa -\-mnobitfield -\-mrtd -\-mshort -\-msoft\-float -.Sp -.I VAX Options -.br -\-mg -\-mgnu -\-munix -.Sp -.I SPARC Options -.br -\-mepilogue -\-mfpu -\-mhard\-float -\-mno\-fpu -\-mno\-epilogue -\-msoft\-float -\-msparclite -\-mv8 -\-msupersparc -\-mcypress -.Sp -.I Convex Options -.br -\-margcount -\-mc1 -\-mc2 -\-mnoargcount -.Sp -.I AMD29K Options -.br -\-m29000 -\-m29050 -\-mbw -\-mdw -\-mkernel\-registers -\-mlarge -\-mnbw -\-mnodw -\-msmall -\-mstack\-check -\-muser\-registers -.Sp -.I M88K Options -.br -\-m88000 -\-m88100 -\-m88110 -\-mbig\-pic -\-mcheck\-zero\-division -\-mhandle\-large\-shift -\-midentify\-revision -\-mno\-check\-zero\-division -\-mno\-ocs\-debug\-info -\-mno\-ocs\-frame\-position -\-mno\-optimize\-arg\-area -\-mno\-serialize\-volatile -\-mno\-underscores -\-mocs\-debug\-info -\-mocs\-frame\-position -\-moptimize\-arg\-area -\-mserialize\-volatile -.RI \-mshort\-data\- num -\-msvr3 -\-msvr4 -\-mtrap\-large\-shift -\-muse\-div\-instruction -\-mversion\-03.00 -\-mwarn\-passed\-structs -.Sp -.I RS6000 Options -.br -\-mfp\-in\-toc -\-mno\-fop\-in\-toc -.Sp -.I RT Options -.br -\-mcall\-lib\-mul -\-mfp\-arg\-in\-fpregs -\-mfp\-arg\-in\-gregs -\-mfull\-fp\-blocks -\-mhc\-struct\-return -\-min\-line\-mul -\-mminimum\-fp\-blocks -\-mnohc\-struct\-return -.Sp -.I MIPS Options -.br -\-mcpu=\fIcpu type\fP -\-mips2 -\-mips3 -\-mint64 -\-mlong64 -\-mlonglong128 -\-mmips\-as -\-mgas -\-mrnames -\-mno\-rnames -\-mgpopt -\-mno\-gpopt -\-mstats -\-mno\-stats -\-mmemcpy -\-mno\-memcpy -\-mno\-mips\-tfile -\-mmips\-tfile -\-msoft\-float -\-mhard\-float -\-mabicalls -\-mno\-abicalls -\-mhalf\-pic -\-mno\-half\-pic -\-G \fInum\fP -\-nocpp -.Sp -.I i386 Options -.br -\-m486 -\-mno\-486 -\-msoft\-float -\-mno\-fp\-ret\-in\-387 -.Sp -.I HPPA Options -.br -\-mpa\-risc\-1\-0 -\-mpa\-risc\-1\-1 -\-mkernel -\-mshared\-libs -\-mno\-shared\-libs -\-mlong\-calls -\-mdisable\-fpregs -\-mdisable\-indexing -\-mtrailing\-colon -.Sp -.I i960 Options -.br -\-m\fIcpu-type\fP -\-mnumerics -\-msoft\-float -\-mleaf\-procedures -\-mno\-leaf\-procedures -\-mtail\-call -\-mno\-tail\-call -\-mcomplex\-addr -\-mno\-complex\-addr -\-mcode\-align -\-mno\-code\-align -\-mic\-compat -\-mic2.0\-compat -\-mic3.0\-compat -\-masm\-compat -\-mintel\-asm -\-mstrict\-align -\-mno\-strict\-align -\-mold\-align -\-mno\-old\-align -.Sp -.I DEC Alpha Options -.br -\-mfp\-regs -\-mno\-fp\-regs -\-mno\-soft\-float -\-msoft\-float -.Sp -.I System V Options -.br -\-G -\-Qy -\-Qn -.RI \-YP, paths -.RI \-Ym, dir -.TP -.B Code Generation Options -.RI \-fcall\-saved\- reg -.RI \-fcall\-used\- reg -.RI \-ffixed\- reg -\-finhibit\-size\-directive -\-fnonnull\-objects -\-fno\-common -\-fno\-ident -\-fno\-gnu\-linker -\-fpcc\-struct\-return -\-fpic -\-fPIC -\-freg\-struct\-return -\-fshared\-data -\-fshort\-enums -\-fshort\-double -\-fvolatile -\-fvolatile\-global -\-fverbose\-asm -.ad b -.hy 1 -.SH OVERALL OPTIONS -.TP -.BI "\-x " "language" -Specify explicitly the -.I language\c -\& for the following input files (rather than choosing a default based -on the file name suffix) . This option applies to all following input -files until the next `\|\c -.B \-x\c -\&\|' option. Possible values of \c -.I language\c -\& are -`\|\c -.B c\c -\&\|', `\|\c -.B objective\-c\c -\&\|', `\|\c -.B c\-header\c -\&\|', `\|\c -.B c++\c -\&\|', -`\|\c -.B cpp\-output\c -\&\|', `\|\c -.B assembler\c -\&\|', and `\|\c -.B assembler\-with\-cpp\c -\&\|'. -.TP -.B \-x none -Turn off any specification of a language, so that subsequent files are -handled according to their file name suffixes (as they are if `\|\c -.B \-x\c -\&\|' -has not been used at all). -.PP -If you want only some of the four stages (preprocess, compile, -assemble, link), you can use -`\|\c -.B \-x\c -\&\|' (or filename suffixes) to tell \c -.B gcc\c -\& where to start, and -one of the options `\|\c -.B \-c\c -\&\|', `\|\c -.B \-S\c -\&\|', or `\|\c -.B \-E\c -\&\|' to say where -.B gcc\c -\& is to stop. Note that some combinations (for example, -`\|\c -.B \-x cpp\-output \-E\c -\&\|') instruct \c -.B gcc\c -\& to do nothing at all. -.TP -.B \-c -Compile or assemble the source files, but do not link. The compiler -output is an object file corresponding to each source file. -.Sp -By default, GCC makes the object file name for a source file by replacing -the suffix `\|\c -.B .c\c -\&\|', `\|\c -.B .i\c -\&\|', `\|\c -.B .s\c -\&\|', etc., with `\|\c -.B .o\c -\&\|'. Use -.B \-o\c -\& to select another name. -.Sp -GCC ignores any unrecognized input files (those that do not require -compilation or assembly) with the -.B \-c -option. -.TP -.B \-S -Stop after the stage of compilation proper; do not assemble. The output -is an assembler code file for each non-assembler input -file specified. -.Sp -By default, GCC makes the assembler file name for a source file by -replacing the suffix `\|\c -.B .c\c -\&\|', `\|\c -.B .i\c -\&\|', etc., with `\|\c -.B .s\c -\&\|'. Use -.B \-o\c -\& to select another name. -.Sp -GCC ignores any input files that don't require compilation. -.TP -.B \-E -Stop after the preprocessing stage; do not run the compiler proper. The -output is preprocessed source code, which is sent to the -standard output. -.Sp -GCC ignores input files which don't require preprocessing. -.TP -.BI "\-o " file -Place output in file \c -.I file\c -\&. This applies regardless to whatever -sort of output GCC is producing, whether it be an executable file, -an object file, an assembler file or preprocessed C code. -.Sp -Since only one output file can be specified, it does not make sense to -use `\|\c -.B \-o\c -\&\|' when compiling more than one input file, unless you are -producing an executable file as output. -.Sp -If you do not specify `\|\c -.B \-o\c -\&\|', the default is to put an executable file -in `\|\c -.B a.out\c -\&\|', the object file for `\|\c -.I source\c -.B \&.\c -.I suffix\c -\&\c -\&\|' in -`\|\c -.I source\c -.B \&.o\c -\&\|', its assembler file in `\|\c -.I source\c -.B \&.s\c -\&\|', and -all preprocessed C source on standard output. -.TP -.B \-v -Print (on standard error output) the commands executed to run the stages -of compilation. Also print the version number of the compiler driver -program and of the preprocessor and the compiler proper. -.TP -.B \-pipe -Use pipes rather than temporary files for communication between the -various stages of compilation. This fails to work on some systems where -the assembler cannot read from a pipe; but the GNU assembler has -no trouble. -.PP -.SH LANGUAGE OPTIONS -The following options control the dialect of C that the compiler -accepts: -.TP -.B \-ansi -Support all ANSI standard C programs. -.Sp -This turns off certain features of GNU C that are incompatible with -ANSI C, such as the \c -.B asm\c -\&, \c -.B inline\c -\& and \c -.B typeof -keywords, and predefined macros such as \c -.B unix\c -\& and \c -.B vax -that identify the type of system you are using. It also enables the -undesirable and rarely used ANSI trigraph feature, and disallows `\|\c -.B $\c -\&\|' as part of identifiers. -.Sp -The alternate keywords \c -.B _\|_asm_\|_\c -\&, \c -.B _\|_extension_\|_\c -\&, -.B _\|_inline_\|_\c -\& and \c -.B _\|_typeof_\|_\c -\& continue to work despite -`\|\c -.B \-ansi\c -\&\|'. You would not want to use them in an ANSI C program, of -course, but it is useful to put them in header files that might be included -in compilations done with `\|\c -.B \-ansi\c -\&\|'. Alternate predefined macros -such as \c -.B _\|_unix_\|_\c -\& and \c -.B _\|_vax_\|_\c -\& are also available, with or -without `\|\c -.B \-ansi\c -\&\|'. -.Sp -The `\|\c -.B \-ansi\c -\&\|' option does not cause non-ANSI programs to be -rejected gratuitously. For that, `\|\c -.B \-pedantic\c -\&\|' is required in -addition to `\|\c -.B \-ansi\c -\&\|'. -.Sp -The preprocessor predefines a macro \c -.B _\|_STRICT_ANSI_\|_\c -\& when you use the `\|\c -.B \-ansi\c -\&\|' -option. Some header files may notice this macro and refrain -from declaring certain functions or defining certain macros that the -ANSI standard doesn't call for; this is to avoid interfering with any -programs that might use these names for other things. -.TP -.B \-fno\-asm -Do not recognize \c -.B asm\c -\&, \c -.B inline\c -\& or \c -.B typeof\c -\& as a -keyword. These words may then be used as identifiers. You can -use \c -.B _\|_asm_\|_\c -\&, \c -.B _\|_inline_\|_\c -\& and \c -.B _\|_typeof_\|_\c -\& instead. -`\|\c -.B \-ansi\c -\&\|' implies `\|\c -.B \-fno\-asm\c -\&\|'. -.TP -.B \-fno\-builtin -Don't recognize built-in functions that do not begin with two leading -underscores. Currently, the functions affected include \c -.B _exit\c -\&, -.B abort\c -\&, \c -.B abs\c -\&, \c -.B alloca\c -\&, \c -.B cos\c -\&, \c -.B exit\c -\&, -.B fabs\c -\&, \c -.B labs\c -\&, \c -.B memcmp\c -\&, \c -.B memcpy\c -\&, \c -.B sin\c -\&, -.B sqrt\c -\&, \c -.B strcmp\c -\&, \c -.B strcpy\c -\&, and \c -.B strlen\c -\&. -.Sp -The `\|\c -.B \-ansi\c -\&\|' option prevents \c -.B alloca\c -\& and \c -.B _exit\c -\& from -being builtin functions. -.TP -.B \-fhosted -Compile for a hosted environment; this implies the `\|\c -.B \-fbuiltin\c -\&\|' option, and implies that suspicious declarations of -.B main\c -\& should be warned about. -.TP -.B \-ffreestanding -Compile for a freestanding environment; this implies the `\|\c -.B \-fno-builtin\c -\&\|' option, and implies that -.B main\c -\& has no special requirements. -.TP -.B \-fno\-strict\-prototype -Treat a function declaration with no arguments, such as `\|\c -.B int foo -();\c -\&\|', as C would treat it\(em\&as saying nothing about the number of -arguments or their types (C++ only). Normally, such a declaration in -C++ means that the function \c -.B foo\c -\& takes no arguments. -.TP -.B \-trigraphs -Support ANSI C trigraphs. The `\|\c -.B \-ansi\c -\&\|' option implies `\|\c -.B \-trigraphs\c -\&\|'. -.TP -.B \-traditional -Attempt to support some aspects of traditional C compilers. -For details, see the GNU C Manual; the duplicate list here -has been deleted so that we won't get complaints when it -is out of date. -.Sp -But one note about C++ programs only (not C). `\|\c -.B \-traditional\c -\&\|' has one additional effect for C++: assignment to -.B this -is permitted. This is the same as the effect of `\|\c -.B \-fthis\-is\-variable\c -\&\|'. -.TP -.B \-traditional\-cpp -Attempt to support some aspects of traditional C preprocessors. -This includes the items that specifically mention the preprocessor above, -but none of the other effects of `\|\c -.B \-traditional\c -\&\|'. -.TP -.B \-fdollars\-in\-identifiers -Permit the use of `\|\c -.B $\c -\&\|' in identifiers (C++ only). You can also use -`\|\c -.B \-fno\-dollars\-in\-identifiers\c -\&\|' to explicitly prohibit use of -`\|\c -.B $\c -\&\|'. (GNU C++ allows `\|\c -.B $\c -\&\|' by default on some target systems -but not others.) -.TP -.B \-fenum\-int\-equiv -Permit implicit conversion of \c -.B int\c -\& to enumeration types (C++ -only). Normally GNU C++ allows conversion of \c -.B enum\c -\& to \c -.B int\c -\&, -but not the other way around. -.TP -.B \-fexternal\-templates -Produce smaller code for template declarations, by generating only a -single copy of each template function where it is defined (C++ only). -To use this option successfully, you must also mark all files that -use templates with either `\|\c -.B #pragma implementation\c -\&\|' (the definition) or -`\|\c -.B #pragma interface\c -\&\|' (declarations). - -When your code is compiled with `\|\c -.B \-fexternal\-templates\c -\&\|', all -template instantiations are external. You must arrange for all -necessary instantiations to appear in the implementation file; you can -do this with a \c -.B typedef\c -\& that references each instantiation needed. -Conversely, when you compile using the default option -`\|\c -.B \-fno\-external\-templates\c -\&\|', all template instantiations are -explicitly internal. -.TP -.B \-fall\-virtual -Treat all possible member functions as virtual, implicitly. All -member functions (except for constructor functions and -.B new -or -.B delete -member operators) are treated as virtual functions of the class where -they appear. -.Sp -This does not mean that all calls to these member functions will be -made through the internal table of virtual functions. Under some -circumstances, the compiler can determine that a call to a given -virtual function can be made directly; in these cases the calls are -direct in any case. -.TP -.B \-fcond\-mismatch -Allow conditional expressions with mismatched types in the second and -third arguments. The value of such an expression is void. -.TP -.B \-fthis\-is\-variable -Permit assignment to \c -.B this\c -\& (C++ only). The incorporation of -user-defined free store management into C++ has made assignment to -`\|\c -.B this\c -\&\|' an anachronism. Therefore, by default it is invalid to -assign to \c -.B this\c -\& within a class member function. However, for -backwards compatibility, you can make it valid with -`\|\c -.B \-fthis-is-variable\c -\&\|'. -.TP -.B \-funsigned\-char -Let the type \c -.B char\c -\& be unsigned, like \c -.B unsigned char\c -\&. -.Sp -Each kind of machine has a default for what \c -.B char\c -\& should -be. It is either like \c -.B unsigned char\c -\& by default or like -.B signed char\c -\& by default. -.Sp -Ideally, a portable program should always use \c -.B signed char\c -\& or -.B unsigned char\c -\& when it depends on the signedness of an object. -But many programs have been written to use plain \c -.B char\c -\& and -expect it to be signed, or expect it to be unsigned, depending on the -machines they were written for. This option, and its inverse, let you -make such a program work with the opposite default. -.Sp -The type \c -.B char\c -\& is always a distinct type from each of -.B signed char\c -\& and \c -.B unsigned char\c -\&, even though its behavior -is always just like one of those two. -.TP -.B \-fsigned\-char -Let the type \c -.B char\c -\& be signed, like \c -.B signed char\c -\&. -.Sp -Note that this is equivalent to `\|\c -.B \-fno\-unsigned\-char\c -\&\|', which is -the negative form of `\|\c -.B \-funsigned\-char\c -\&\|'. Likewise, -`\|\c -.B \-fno\-signed\-char\c -\&\|' is equivalent to `\|\c -.B \-funsigned\-char\c -\&\|'. -.TP -.B \-fsigned\-bitfields -.TP -.B \-funsigned\-bitfields -.TP -.B \-fno\-signed\-bitfields -.TP -.B \-fno\-unsigned\-bitfields -These options control whether a bitfield is -signed or unsigned, when declared with no explicit `\|\c -.B signed\c -\&\|' or `\|\c -.B unsigned\c -\&\|' qualifier. By default, such a bitfield is -signed, because this is consistent: the basic integer types such as -.B int\c -\& are signed types. -.Sp -However, when you specify `\|\c -.B \-traditional\c -\&\|', bitfields are all unsigned -no matter what. -.TP -.B \-fwritable\-strings -Store string constants in the writable data segment and don't uniquize -them. This is for compatibility with old programs which assume they -can write into string constants. `\|\c -.B \-traditional\c -\&\|' also has this -effect. -.Sp -Writing into string constants is a very bad idea; \*(lqconstants\*(rq should -be constant. -.SH PREPROCESSOR OPTIONS -These options control the C preprocessor, which is run on each C source -file before actual compilation. -.PP -If you use the `\|\c -.B \-E\c -\&\|' option, GCC does nothing except preprocessing. -Some of these options make sense only together with `\|\c -.B \-E\c -\&\|' because -they cause the preprocessor output to be unsuitable for actual -compilation. -.TP -.BI "\-include " "file" -Process \c -.I file\c -\& as input before processing the regular input file. -In effect, the contents of \c -.I file\c -\& are compiled first. Any `\|\c -.B \-D\c -\&\|' -and `\|\c -.B \-U\c -\&\|' options on the command line are always processed before -`\|\c -.B \-include \c -.I file\c -\&\c -\&\|', regardless of the order in which they are -written. All the `\|\c -.B \-include\c -\&\|' and `\|\c -.B \-imacros\c -\&\|' options are -processed in the order in which they are written. -.TP -.BI "\-imacros " file -Process \c -.I file\c -\& as input, discarding the resulting output, before -processing the regular input file. Because the output generated from -.I file\c -\& is discarded, the only effect of `\|\c -.B \-imacros \c -.I file\c -\&\c -\&\|' is to -make the macros defined in \c -.I file\c -\& available for use in the main -input. The preprocessor evaluates any `\|\c -.B \-D\c -\&\|' and `\|\c -.B \-U\c -\&\|' options -on the command line before processing `\|\c -.B \-imacros\c -.I file\c -\&\|', regardless of the order in -which they are written. All the `\|\c -.B \-include\c -\&\|' and `\|\c -.B \-imacros\c -\&\|' -options are processed in the order in which they are written. -.TP -.BI "\-idirafter " "dir" -Add the directory \c -.I dir\c -\& to the second include path. The directories -on the second include path are searched when a header file is not found -in any of the directories in the main include path (the one that -`\|\c -.B \-I\c -\&\|' adds to). -.TP -.BI "\-iprefix " "prefix" -Specify \c -.I prefix\c -\& as the prefix for subsequent `\|\c -.B \-iwithprefix\c -\&\|' -options. -.TP -.BI "\-iwithprefix " "dir" -Add a directory to the second include path. The directory's name is -made by concatenating \c -.I prefix\c -\& and \c -.I dir\c -\&, where \c -.I prefix -was specified previously with `\|\c -.B \-iprefix\c -\&\|'. -.TP -.B \-nostdinc -Do not search the standard system directories for header files. Only -the directories you have specified with `\|\c -.B \-I\c -\&\|' options (and the -current directory, if appropriate) are searched. -.Sp -By using both `\|\c -.B \-nostdinc\c -\&\|' and `\|\c -.B \-I\-\c -\&\|', you can limit the include-file search file to only those -directories you specify explicitly. -.TP -.B \-nostdinc++ -Do not search for header files in the C++\-specific standard directories, -but do still search the other standard directories. -(This option is used when building `\|\c -.B libg++\c -\&\|'.) -.TP -.B \-undef -Do not predefine any nonstandard macros. (Including architecture flags). -.TP -.B \-E -Run only the C preprocessor. Preprocess all the C source files -specified and output the results to standard output or to the -specified output file. -.TP -.B \-C -Tell the preprocessor not to discard comments. Used with the -`\|\c -.B \-E\c -\&\|' option. -.TP -.B \-P -Tell the preprocessor not to generate `\|\c -.B #line\c -\&\|' commands. -Used with the `\|\c -.B \-E\c -\&\|' option. -.TP -.B \-M\ [ \-MG ] -Tell the preprocessor to output a rule suitable for \c -.B make -describing the dependencies of each object file. For each source file, -the preprocessor outputs one \c -.B make\c -\&-rule whose target is the object -file name for that source file and whose dependencies are all the files -`\|\c -.B #include\c -\&\|'d in it. This rule may be a single line or may be -continued with `\|\c -.B \e\c -\&\|'-newline if it is long. The list of rules is -printed on standard output instead of the preprocessed C program. -.Sp -`\|\c -.B \-M\c -\&\|' implies `\|\c -.B \-E\c -\&\|'. -.Sp -`\|\c -.B \-MG\c -\&\|' says to treat missing header files as generated files and assume \c -they live in the same directory as the source file. It must be specified \c -in addition to `\|\c -.B \-M\c -\&\|'. -.TP -.B \-MM\ [ \-MG ] -Like `\|\c -.B \-M\c -\&\|' but the output mentions only the user header files -included with `\|\c -.B #include "\c -.I file\c -\&"\c -\&\|'. System header files -included with `\|\c -.B #include <\c -.I file\c -\&>\c -\&\|' are omitted. -.TP -.B \-MD -Like `\|\c -.B \-M\c -\&\|' but the dependency information is written to files with -names made by replacing `\|\c -.B .o\c -\&\|' with `\|\c -.B .d\c -\&\|' at the end of the -output file names. This is in addition to compiling the file as -specified\(em\&`\|\c -.B \-MD\c -\&\|' does not inhibit ordinary compilation the way -`\|\c -.B \-M\c -\&\|' does. -.Sp -The Mach utility `\|\c -.B md\c -\&\|' can be used to merge the `\|\c -.B .d\c -\&\|' files -into a single dependency file suitable for using with the `\|\c -.B make\c -\&\|' -command. -.TP -.B \-MMD -Like `\|\c -.B \-MD\c -\&\|' except mention only user header files, not system -header files. -.TP -.B \-H -Print the name of each header file used, in addition to other normal -activities. -.TP -.BI "\-A" "question" ( answer ) -Assert the answer -.I answer -for -.I question\c -\&, in case it is tested -with a preprocessor conditional such as `\|\c -.BI "#if #" question ( answer )\c -\&\|'. `\|\c -.B \-A\-\c -\&\|' disables the standard -assertions that normally describe the target machine. -.TP -.BI "\-A" "question"\c -\&(\c -.I answer\c -\&) -Assert the answer \c -.I answer\c -\& for \c -.I question\c -\&, in case it is tested -with a preprocessor conditional such as `\|\c -.B #if -#\c -.I question\c -\&(\c -.I answer\c -\&)\c -\&\|'. `\|\c -.B \-A-\c -\&\|' disables the standard -assertions that normally describe the target machine. -.TP -.BI \-D macro -Define macro \c -.I macro\c -\& with the string `\|\c -.B 1\c -\&\|' as its definition. -.TP -.BI \-D macro = defn -Define macro \c -.I macro\c -\& as \c -.I defn\c -\&. All instances of `\|\c -.B \-D\c -\&\|' on -the command line are processed before any `\|\c -.B \-U\c -\&\|' options. -.TP -.BI \-U macro -Undefine macro \c -.I macro\c -\&. `\|\c -.B \-U\c -\&\|' options are evaluated after all `\|\c -.B \-D\c -\&\|' options, but before any `\|\c -.B \-include\c -\&\|' and `\|\c -.B \-imacros\c -\&\|' options. -.TP -.B \-dM -Tell the preprocessor to output only a list of the macro definitions -that are in effect at the end of preprocessing. Used with the `\|\c -.B \-E\c -\&\|' -option. -.TP -.B \-dD -Tell the preprocessor to pass all macro definitions into the output, in -their proper sequence in the rest of the output. -.TP -.B \-dN -Like `\|\c -.B \-dD\c -\&\|' except that the macro arguments and contents are omitted. -Only `\|\c -.B #define \c -.I name\c -\&\c -\&\|' is included in the output. -.SH ASSEMBLER OPTION -.TP -.BI "\-Wa," "option" -Pass \c -.I option\c -\& as an option to the assembler. If \c -.I option -contains commas, it is split into multiple options at the commas. -.SH LINKER OPTIONS -These options come into play when the compiler links object files into -an executable output file. They are meaningless if the compiler is -not doing a link step. -.TP -.I object-file-name -A file name that does not end in a special recognized suffix is -considered to name an object file or library. (Object files are -distinguished from libraries by the linker according to the file -contents.) If GCC does a link step, these object files are used as input -to the linker. -.TP -.BI \-l library -Use the library named \c -.I library\c -\& when linking. -.Sp -The linker searches a standard list of directories for the library, -which is actually a file named `\|\c -.B lib\c -.I library\c -\&.a\c -\&\|'. The linker -then uses this file as if it had been specified precisely by name. -.Sp -The directories searched include several standard system directories -plus any that you specify with `\|\c -.B \-L\c -\&\|'. -.Sp -Normally the files found this way are library files\(em\&archive files -whose members are object files. The linker handles an archive file by -scanning through it for members which define symbols that have so far -been referenced but not defined. However, if the linker finds an -ordinary object file rather than a library, the object file is linked -in the usual fashion. The only difference between using an `\|\c -.B \-l\c -\&\|' option and specifying a file -name is that `\|\c -.B \-l\c -\&\|' surrounds -.I library -with `\|\c -.B lib\c -\&\|' and `\|\c -.B .a\c -\&\|' and searches several directories. -.TP -.B \-lobjc -You need this special case of the -.B \-l -option in order to link an Objective C program. -.TP -.B \-nostartfiles -Do not use the standard system startup files when linking. -The standard libraries are used normally. -.TP -.B \-nostdlib -Don't use the standard system libraries and startup files when linking. -Only the files you specify will be passed to the linker. -.TP -.B \-static -On systems that support dynamic linking, this prevents linking with the shared -libraries. On other systems, this option has no effect. -.TP -.B \-shared -Produce a shared object which can then be linked with other objects to -form an executable. Only a few systems support this option. -.TP -.B \-symbolic -Bind references to global symbols when building a shared object. Warn -about any unresolved references (unless overridden by the link editor -option `\|\c -.B -\-Xlinker \-z \-Xlinker defs\c -\&\|'). Only a few systems support -this option. -.TP -.BI "\-Xlinker " "option" -Pass \c -.I option -as an option to the linker. You can use this to -supply system-specific linker options which GNU CC does not know how to -recognize. -.Sp -If you want to pass an option that takes an argument, you must use -`\|\c -.B \-Xlinker\c -\&\|' twice, once for the option and once for the argument. -For example, to pass `\|\c -.B -\-assert definitions\c -\&\|', you must write -`\|\c -.B -\-Xlinker \-assert \-Xlinker definitions\c -\&\|'. It does not work to write -`\|\c -.B -\-Xlinker "\-assert definitions"\c -\&\|', because this passes the entire -string as a single argument, which is not what the linker expects. -.TP -.BI "\-Wl," "option" -Pass \c -.I option\c -\& as an option to the linker. If \c -.I option\c -\& contains -commas, it is split into multiple options at the commas. -.TP -.BI "\-u " "symbol" -Pretend the symbol -.I symbol -is undefined, to force linking of -library modules to define it. You can use `\|\c -.B \-u\c -\&\|' multiple times with -different symbols to force loading of additional library modules. -.SH DIRECTORY OPTIONS -These options specify directories to search for header files, for -libraries and for parts of the compiler: -.TP -.BI "\-I" "dir" -Append directory \c -.I dir\c -\& to the list of directories searched for include files. -.TP -.B \-I\- -Any directories you specify with `\|\c -.B \-I\c -\&\|' options before the `\|\c -.B \-I\-\c -\&\|' -option are searched only for the case of `\|\c -.B -#include "\c -.I file\c -.B -\&"\c -\&\|'; -they are not searched for `\|\c -.B #include <\c -.I file\c -\&>\c -\&\|'. -.Sp -If additional directories are specified with `\|\c -.B \-I\c -\&\|' options after -the `\|\c -.B \-I\-\c -\&\|', these directories are searched for all `\|\c -.B #include\c -\&\|' -directives. (Ordinarily \c -.I all\c -\& `\|\c -.B \-I\c -\&\|' directories are used -this way.) -.Sp -In addition, the `\|\c -.B \-I\-\c -\&\|' option inhibits the use of the current -directory (where the current input file came from) as the first search -directory for `\|\c -.B -#include "\c -.I file\c -.B -\&"\c -\&\|'. There is no way to -override this effect of `\|\c -.B \-I\-\c -\&\|'. With `\|\c -.B \-I.\c -\&\|' you can specify -searching the directory which was current when the compiler was -invoked. That is not exactly the same as what the preprocessor does -by default, but it is often satisfactory. -.Sp -`\|\c -.B \-I\-\c -\&\|' does not inhibit the use of the standard system directories -for header files. Thus, `\|\c -.B \-I\-\c -\&\|' and `\|\c -.B \-nostdinc\c -\&\|' are -independent. -.TP -.BI "\-L" "dir" -Add directory \c -.I dir\c -\& to the list of directories to be searched -for `\|\c -.B \-l\c -\&\|'. -.TP -.BI "\-B" "prefix" -This option specifies where to find the executables, libraries and -data files of the compiler itself. -.Sp -The compiler driver program runs one or more of the subprograms -`\|\c -.B cpp\c -\&\|', `\|\c -.B cc1\c -\&\|' (or, for C++, `\|\c -.B cc1plus\c -\&\|'), `\|\c -.B as\c -\&\|' and `\|\c -.B ld\c -\&\|'. It tries -.I prefix\c -\& as a prefix for each program it tries to run, both with and -without `\|\c -.I machine\c -.B /\c -.I version\c -.B /\c -\&\|'. -.Sp -For each subprogram to be run, the compiler driver first tries the -`\|\c -.B \-B\c -\&\|' prefix, if any. If that name is not found, or if `\|\c -.B \-B\c -\&\|' -was not specified, the driver tries two standard prefixes, which are -`\|\c -.B /usr/lib/gcc/\c -\&\|' and `\|\c -.B /usr/local/lib/gcc-lib/\c -\&\|'. If neither of -those results in a file name that is found, the compiler driver -searches for the unmodified program -name, using the directories specified in your -`\|\c -.B PATH\c -\&\|' environment variable. -.Sp -The run-time support file `\|\c -.B libgcc.a\c -\&\|' is also searched for using the -`\|\c -.B \-B\c -\&\|' prefix, if needed. If it is not found there, the two -standard prefixes above are tried, and that is all. The file is left -out of the link if it is not found by those means. Most of the time, -on most machines, `\|\c -.B libgcc.a\c -\&\|' is not actually necessary. -.Sp -You can get a similar result from the environment variable -.B GCC_EXEC_PREFIX\c -\&; if it is defined, its value is used as a prefix -in the same way. If both the `\|\c -.B \-B\c -\&\|' option and the -.B GCC_EXEC_PREFIX\c -\& variable are present, the `\|\c -.B \-B\c -\&\|' option is -used first and the environment variable value second. -.SH WARNING OPTIONS -Warnings are diagnostic messages that report constructions which -are not inherently erroneous but which are risky or suggest there -may have been an error. -.Sp -These options control the amount and kinds of warnings produced by GNU -CC: -.TP -.B \-fsyntax\-only -Check the code for syntax errors, but don't emit any output. -.TP -.B \-w -Inhibit all warning messages. -.TP -.B \-Wno\-import -Inhibit warning messages about the use of -.BR #import . -.TP -.B \-pedantic -Issue all the warnings demanded by strict ANSI standard C; reject -all programs that use forbidden extensions. -.Sp -Valid ANSI standard C programs should compile properly with or without -this option (though a rare few will require `\|\c -.B \-ansi\c -\&\|'). However, -without this option, certain GNU extensions and traditional C features -are supported as well. With this option, they are rejected. There is -no reason to \c -.I use\c -\& this option; it exists only to satisfy pedants. -.Sp -`\|\c -.B \-pedantic\c -\&\|' does not cause warning messages for use of the -alternate keywords whose names begin and end with `\|\c -.B _\|_\c -\&\|'. Pedantic -warnings are also disabled in the expression that follows -.B _\|_extension_\|_\c -\&. However, only system header files should use -these escape routes; application programs should avoid them. -.TP -.B \-pedantic\-errors -Like `\|\c -.B \-pedantic\c -\&\|', except that errors are produced rather than -warnings. -.TP -.B \-W -Print extra warning messages for these events: -.TP -\ \ \ \(bu -A nonvolatile automatic variable might be changed by a call to -.B longjmp\c -\&. These warnings are possible only in -optimizing compilation. -.Sp -The compiler sees only the calls to \c -.B setjmp\c -\&. It cannot know -where \c -.B longjmp\c -\& will be called; in fact, a signal handler could -call it at any point in the code. As a result, you may get a warning -even when there is in fact no problem because \c -.B longjmp\c -\& cannot -in fact be called at the place which would cause a problem. -.TP -\ \ \ \(bu -A function can return either with or without a value. (Falling -off the end of the function body is considered returning without -a value.) For example, this function would evoke such a -warning: -.Sp -.nf -foo (a) -{ - if (a > 0) - return a; -} -.Sp -.fi -Spurious warnings can occur because GNU CC does not realize that -certain functions (including \c -.B abort\c -\& and \c -.B longjmp\c -\&) -will never return. -.TP -\ \ \ \(bu -An expression-statement or the left-hand side of a comma expression -contains no side effects. -To suppress the warning, cast the unused expression to void. -For example, an expression such as `\|\c -.B x[i,j]\c -\&\|' will cause a warning, -but `\|\c -.B x[(void)i,j]\c -\&\|' will not. -.TP -\ \ \ \(bu -An unsigned value is compared against zero with `\|\c -.B >\c -\&\|' or `\|\c -.B <=\c -\&\|'. -.PP -.TP -.B \-Wimplicit-int -Warn whenever a declaration does not specify a type. -.TP -.B \-Wimplicit-function-declaration -Warn whenever a function is used before being declared. -.TP -.B \-Wimplicit -Same as -Wimplicit-int and -Wimplicit-function-declaration. -.TP -.B \-Wmain -Warn if the -.B main -function is declared or defined with a suspicious type. -Typically, it is a function with external linkage, returning -.B int\c -\&, and -taking zero or two arguments. - -.TP -.B \-Wreturn\-type -Warn whenever a function is defined with a return-type that defaults -to \c -.B int\c -\&. Also warn about any \c -.B return\c -\& statement with no -return-value in a function whose return-type is not \c -.B void\c -\&. -.TP -.B \-Wunused -Warn whenever a local variable is unused aside from its declaration, -whenever a function is declared static but never defined, and whenever -a statement computes a result that is explicitly not used. -.TP -.B \-Wswitch -Warn whenever a \c -.B switch\c -\& statement has an index of enumeral type -and lacks a \c -.B case\c -\& for one or more of the named codes of that -enumeration. (The presence of a \c -.B default\c -\& label prevents this -warning.) \c -.B case\c -\& labels outside the enumeration range also -provoke warnings when this option is used. -.TP -.B \-Wcomment -Warn whenever a comment-start sequence `\|\c -.B /\(**\c -\&\|' appears in a comment. -.TP -.B \-Wtrigraphs -Warn if any trigraphs are encountered (assuming they are enabled). -.TP -.B \-Wformat -Check calls to \c -.B printf\c -\& and \c -.B scanf\c -\&, etc., to make sure that -the arguments supplied have types appropriate to the format string -specified. -.TP -.B \-Wchar\-subscripts -Warn if an array subscript has type -.BR char . -This is a common cause of error, as programmers often forget that this -type is signed on some machines. -.TP -.B \-Wuninitialized -An automatic variable is used without first being initialized. -.Sp -These warnings are possible only in optimizing compilation, -because they require data flow information that is computed only -when optimizing. If you don't specify `\|\c -.B \-O\c -\&\|', you simply won't -get these warnings. -.Sp -These warnings occur only for variables that are candidates for -register allocation. Therefore, they do not occur for a variable that -is declared \c -.B volatile\c -\&, or whose address is taken, or whose size -is other than 1, 2, 4 or 8 bytes. Also, they do not occur for -structures, unions or arrays, even when they are in registers. -.Sp -Note that there may be no warning about a variable that is used only -to compute a value that itself is never used, because such -computations may be deleted by data flow analysis before the warnings -are printed. -.Sp -These warnings are made optional because GNU CC is not smart -enough to see all the reasons why the code might be correct -despite appearing to have an error. Here is one example of how -this can happen: -.Sp -.nf -{ - int x; - switch (y) - { - case 1: x = 1; - break; - case 2: x = 4; - break; - case 3: x = 5; - } - foo (x); -} -.Sp -.fi -If the value of \c -.B y\c -\& is always 1, 2 or 3, then \c -.B x\c -\& is -always initialized, but GNU CC doesn't know this. Here is -another common case: -.Sp -.nf -{ - int save_y; - if (change_y) save_y = y, y = new_y; - .\|.\|. - if (change_y) y = save_y; -} -.Sp -.fi -This has no bug because \c -.B save_y\c -\& is used only if it is set. -.Sp -Some spurious warnings can be avoided if you declare as -.B volatile\c -\& all the functions you use that never return. -.TP -.B \-Wparentheses -Warn if parentheses are omitted in certain contexts. -.TP -.B \-Wtemplate\-debugging -When using templates in a C++ program, warn if debugging is not yet -fully available (C++ only). -.TP -.B \-Wall -All of the above `\|\c -.B \-W\c -\&\|' options combined. These are all the -options which pertain to usage that we recommend avoiding and that we -believe is easy to avoid, even in conjunction with macros. -.PP -The remaining `\|\c -.B \-W.\|.\|.\c -\&\|' options are not implied by `\|\c -.B \-Wall\c -\&\|' -because they warn about constructions that we consider reasonable to -use, on occasion, in clean programs. -.TP -.B \-Wtraditional -Warn about certain constructs that behave differently in traditional and -ANSI C. -.TP -\ \ \ \(bu -Macro arguments occurring within string constants in the macro body. -These would substitute the argument in traditional C, but are part of -the constant in ANSI C. -.TP -\ \ \ \(bu -A function declared external in one block and then used after the end of -the block. -.TP -\ \ \ \(bu -A \c -.B switch\c -\& statement has an operand of type \c -.B long\c -\&. -.PP -.TP -.B \-Wshadow -Warn whenever a local variable shadows another local variable. -.TP -.BI "\-Wid\-clash\-" "len" -Warn whenever two distinct identifiers match in the first \c -.I len -characters. This may help you prepare a program that will compile -with certain obsolete, brain-damaged compilers. -.TP -.B \-Wpointer\-arith -Warn about anything that depends on the \*(lqsize of\*(rq a function type or -of \c -.B void\c -\&. GNU C assigns these types a size of 1, for -convenience in calculations with \c -.B void \(**\c -\& pointers and pointers -to functions. -.TP -.B \-Wcast\-qual -Warn whenever a pointer is cast so as to remove a type qualifier from -the target type. For example, warn if a \c -.B const char \(**\c -\& is cast -to an ordinary \c -.B char \(**\c -\&. -.TP -.B \-Wcast\-align -Warn whenever a pointer is cast such that the required alignment of the -target is increased. For example, warn if a \c -.B char \(**\c -\& is cast to -an \c -.B int \(**\c -\& on machines where integers can only be accessed at -two- or four-byte boundaries. -.TP -.B \-Wwrite\-strings -Give string constants the type \c -.B const char[\c -.I length\c -.B ]\c -\& so that -copying the address of one into a non-\c -.B const\c -\& \c -.B char \(** -pointer will get a warning. These warnings will help you find at -compile time code that can try to write into a string constant, but -only if you have been very careful about using \c -.B const\c -\& in -declarations and prototypes. Otherwise, it will just be a nuisance; -this is why we did not make `\|\c -.B \-Wall\c -\&\|' request these warnings. -.TP -.B \-Wconversion -Warn if a prototype causes a type conversion that is different from what -would happen to the same argument in the absence of a prototype. This -includes conversions of fixed point to floating and vice versa, and -conversions changing the width or signedness of a fixed point argument -except when the same as the default promotion. -.TP -.B \-Waggregate\-return -Warn if any functions that return structures or unions are defined or -called. (In languages where you can return an array, this also elicits -a warning.) -.TP -.B \-Wstrict\-prototypes -Warn if a function is declared or defined without specifying the -argument types. (An old-style function definition is permitted without -a warning if preceded by a declaration which specifies the argument -types.) -.TP -.B \-Wmissing\-prototypes -Warn if a global function is defined without a previous prototype -declaration. This warning is issued even if the definition itself -provides a prototype. The aim is to detect global functions that fail -to be declared in header files. -.TP -.B \-Wmissing\-declarations -Warn if a global function is defined without a previous declaration. -Do so even if the definition itself provides a prototype. -Use this option to detect global functions that are not declared in -header files. -.TP -.B \-Wredundant-decls -Warn if anything is declared more than once in the same scope, even in -cases where multiple declaration is valid and changes nothing. -.TP -.B \-Wnested-externs -Warn if an \c -.B extern\c -\& declaration is encountered within an function. -.TP -.B \-Wenum\-clash -Warn about conversion between different enumeration types (C++ only). -.TP -.B \-Wlong-long -Warn if -.B long long \c -type is used. This is default. To inhibit -the warning messages, use flag `\|\c -.B \-Wno\-long\-long\c -\&\|'. Flags `\|\c -.B \-W\-long\-long\c -\&\|' and `\|\c -.B \-Wno\-long\-long\c -\&\|' are taken into account only when flag `\|\c -.B \-pedantic\c -\&\|' is used. -.TP -.B \-Woverloaded\-virtual -(C++ only.) -In a derived class, the definitions of virtual functions must match -the type signature of a virtual function declared in the base class. -Use this option to request warnings when a derived class declares a -function that may be an erroneous attempt to define a virtual -function: that is, warn when a function with the same name as a -virtual function in the base class, but with a type signature that -doesn't match any virtual functions from the base class. -.TP -.B \-Winline -Warn if a function can not be inlined, and either it was declared as inline, -or else the -.B \-finline\-functions -option was given. -.TP -.B \-Werror -Treat warnings as errors; abort compilation after any warning. -.SH DEBUGGING OPTIONS -GNU CC has various special options that are used for debugging -either your program or GCC: -.TP -.B \-g -Produce debugging information in the operating system's native format -(stabs, COFF, XCOFF, or DWARF). GDB can work with this debugging -information. -.Sp -On most systems that use stabs format, `\|\c -.B \-g\c -\&\|' enables use of extra -debugging information that only GDB can use; this extra information -makes debugging work better in GDB but will probably make other debuggers -crash or -refuse to read the program. If you want to control for certain whether -to generate the extra information, use `\|\c -.B \-gstabs+\c -\&\|', `\|\c -.B \-gstabs\c -\&\|', -`\|\c -.B \-gxcoff+\c -\&\|', `\|\c -.B \-gxcoff\c -\&\|', `\|\c -.B \-gdwarf+\c -\&\|', or `\|\c -.B \-gdwarf\c -\&\|' -(see below). -.Sp -Unlike most other C compilers, GNU CC allows you to use `\|\c -.B \-g\c -\&\|' with -`\|\c -.B \-O\c -\&\|'. The shortcuts taken by optimized code may occasionally -produce surprising results: some variables you declared may not exist -at all; flow of control may briefly move where you did not expect it; -some statements may not be executed because they compute constant -results or their values were already at hand; some statements may -execute in different places because they were moved out of loops. -.Sp -Nevertheless it proves possible to debug optimized output. This makes -it reasonable to use the optimizer for programs that might have bugs. -.PP -The following options are useful when GNU CC is generated with the -capability for more than one debugging format. -.TP -.B \-ggdb -Produce debugging information in the native format (if that is supported), -including GDB extensions if at all possible. -.TP -.B \-gstabs -Produce debugging information in stabs format (if that is supported), -without GDB extensions. This is the format used by DBX on most BSD -systems. -.TP -.B \-gstabs+ -Produce debugging information in stabs format (if that is supported), -using GNU extensions understood only by the GNU debugger (GDB). The -use of these extensions is likely to make other debuggers crash or -refuse to read the program. -.TP -.B \-gcoff -Produce debugging information in COFF format (if that is supported). -This is the format used by SDB on most System V systems prior to -System V Release 4. -.TP -.B \-gxcoff -Produce debugging information in XCOFF format (if that is supported). -This is the format used by the DBX debugger on IBM RS/6000 systems. -.TP -.B \-gxcoff+ -Produce debugging information in XCOFF format (if that is supported), -using GNU extensions understood only by the GNU debugger (GDB). The -use of these extensions is likely to make other debuggers crash or -refuse to read the program. -.TP -.B \-gdwarf -Produce debugging information in DWARF format (if that is supported). -This is the format used by SDB on most System V Release 4 systems. -.TP -.B \-gdwarf+ -Produce debugging information in DWARF format (if that is supported), -using GNU extensions understood only by the GNU debugger (GDB). The -use of these extensions is likely to make other debuggers crash or -refuse to read the program. -.PP -.BI "\-g" "level" -.br -.BI "\-ggdb" "level" -.br -.BI "\-gstabs" "level" -.br -.BI "\-gcoff" "level" -.BI "\-gxcoff" "level" -.TP -.BI "\-gdwarf" "level" -Request debugging information and also use \c -.I level\c -\& to specify how -much information. The default level is 2. -.Sp -Level 1 produces minimal information, enough for making backtraces in -parts of the program that you don't plan to debug. This includes -descriptions of functions and external variables, but no information -about local variables and no line numbers. -.Sp -Level 3 includes extra information, such as all the macro definitions -present in the program. Some debuggers support macro expansion when -you use `\|\c -.B \-g3\c -\&\|'. -.TP -.B \-p -Generate extra code to write profile information suitable for the -analysis program \c -.B prof\c -\&. -.TP -.B \-pg -Generate extra code to write profile information suitable for the -analysis program \c -.B gprof\c -\&. -.TP -.B \-a -Generate extra code to write profile information for basic blocks, -which will record the number of times each basic block is executed. -This data could be analyzed by a program like \c -.B tcov\c -\&. Note, -however, that the format of the data is not what \c -.B tcov\c -\& expects. -Eventually GNU \c -.B gprof\c -\& should be extended to process this data. -.TP -.B \-ax -Generate extra code to read basic block profiling parameters from -file `bb.in' and write profiling results to file `bb.out'. -`bb.in' contains a list of functions. Whenever a function on the list -is entered, profiling is turned on. When the outmost function is left, -profiling is turned off. If a function name is prefixed with `-' -the function is excluded from profiling. If a function name is not -unique it can be disambiguated by writing -`/path/filename.d:functionname'. `bb.out' will list some available -filenames. -Four function names have a special meaning: -`__bb_jumps__' will cause jump frequencies to be written to `bb.out'. -`__bb_trace__' will cause the sequence of basic blocks to be piped -into `gzip' and written to file `bbtrace.gz'. -`__bb_hidecall__' will cause call instructions to be excluded from -the trace. -`__bb_showret__' will cause return instructions to be included in -the trace. -.TP -.BI "\-d" "letters" -Says to make debugging dumps during compilation at times specified by -.I letters\c -\&. This is used for debugging the compiler. The file names -for most of the dumps are made by appending a word to the source file -name (e.g. `\|\c -.B foo.c.rtl\c -\&\|' or `\|\c -.B foo.c.jump\c -\&\|'). -.TP -.B \-dM -Dump all macro definitions, at the end of preprocessing, and write no -output. -.TP -.B \-dN -Dump all macro names, at the end of preprocessing. -.TP -.B \-dD -Dump all macro definitions, at the end of preprocessing, in addition to -normal output. -.TP -.B \-dy -Dump debugging information during parsing, to standard error. -.TP -.B \-dr -Dump after RTL generation, to `\|\c -.I file\c -.B \&.rtl\c -\&\|'. -.TP -.B \-dx -Just generate RTL for a function instead of compiling it. Usually used -with `\|\c -.B r\c -\&\|'. -.TP -.B \-dj -Dump after first jump optimization, to `\|\c -.I file\c -.B \&.jump\c -\&\|'. -.TP -.B \-ds -Dump after CSE (including the jump optimization that sometimes -follows CSE), to `\|\c -.I file\c -.B \&.cse\c -\&\|'. -.TP -.B \-dL -Dump after loop optimization, to `\|\c -.I file\c -.B \&.loop\c -\&\|'. -.TP -.B \-dt -Dump after the second CSE pass (including the jump optimization that -sometimes follows CSE), to `\|\c -.I file\c -.B \&.cse2\c -\&\|'. -.TP -.B \-df -Dump after flow analysis, to `\|\c -.I file\c -.B \&.flow\c -\&\|'. -.TP -.B \-dc -Dump after instruction combination, to `\|\c -.I file\c -.B \&.combine\c -\&\|'. -.TP -.B \-dS -Dump after the first instruction scheduling pass, to -`\|\c -.I file\c -.B \&.sched\c -\&\|'. -.TP -.B \-dl -Dump after local register allocation, to `\|\c -.I file\c -.B \&.lreg\c -\&\|'. -.TP -.B \-dg -Dump after global register allocation, to `\|\c -.I file\c -.B \&.greg\c -\&\|'. -.TP -.B \-dR -Dump after the second instruction scheduling pass, to -`\|\c -.I file\c -.B \&.sched2\c -\&\|'. -.TP -.B \-dJ -Dump after last jump optimization, to `\|\c -.I file\c -.B \&.jump2\c -\&\|'. -.TP -.B \-dd -Dump after delayed branch scheduling, to `\|\c -.I file\c -.B \&.dbr\c -\&\|'. -.TP -.B \-dk -Dump after conversion from registers to stack, to `\|\c -.I file\c -.B \&.stack\c -\&\|'. -.TP -.B \-da -Produce all the dumps listed above. -.TP -.B \-dm -Print statistics on memory usage, at the end of the run, to -standard error. -.TP -.B \-dp -Annotate the assembler output with a comment indicating which -pattern and alternative was used. -.TP -.B \-fpretend\-float -When running a cross-compiler, pretend that the target machine uses the -same floating point format as the host machine. This causes incorrect -output of the actual floating constants, but the actual instruction -sequence will probably be the same as GNU CC would make when running on -the target machine. -.TP -.B \-save\-temps -Store the usual \*(lqtemporary\*(rq intermediate files permanently; place them -in the current directory and name them based on the source file. Thus, -compiling `\|\c -.B foo.c\c -\&\|' with `\|\c -.B \-c \-save\-temps\c -\&\|' would produce files -`\|\c -.B foo.cpp\c -\&\|' and `\|\c -.B foo.s\c -\&\|', as well as `\|\c -.B foo.o\c -\&\|'. -.TP -.BI "\-print\-file\-name=" "library" -Print the full absolute name of the library file \|\c -.nh -.I library -.hy -\&\| that -would be used when linking\(em\&and do not do anything else. With this -option, GNU CC does not compile or link anything; it just prints the -file name. -.TP -.B \-print\-libgcc\-file\-name -Same as `\|\c -.B \-print\-file\-name=libgcc.a\c -\&\|'. -.TP -.BI "\-print\-prog\-name=" "program" -Like `\|\c -.B \-print\-file\-name\c -\&\|', but searches for a program such as `\|\c -cpp\c -\&\|'. -.SH OPTIMIZATION OPTIONS -These options control various sorts of optimizations: -.TP -.B \-O -.TP -.B \-O1 -Optimize. Optimizing compilation takes somewhat more time, and a lot -more memory for a large function. -.Sp -Without `\|\c -.B \-O\c -\&\|', the compiler's goal is to reduce the cost of -compilation and to make debugging produce the expected results. -Statements are independent: if you stop the program with a breakpoint -between statements, you can then assign a new value to any variable or -change the program counter to any other statement in the function and -get exactly the results you would expect from the source code. -.Sp -Without `\|\c -.B \-O\c -\&\|', only variables declared \c -.B register\c -\& are -allocated in registers. The resulting compiled code is a little worse -than produced by PCC without `\|\c -.B \-O\c -\&\|'. -.Sp -With `\|\c -.B \-O\c -\&\|', the compiler tries to reduce code size and execution -time. -.Sp -When you specify `\|\c -.B \-O\c -\&\|', the two options `\|\c -.B \-fthread\-jumps\c -\&\|' and `\|\c -.B \-fdefer\-pop\c -\&\|' are turned on. On machines that have delay slots, the `\|\c -.B \-fdelayed\-branch\c -\&\|' option is turned on. For those machines that can support debugging even -without a frame pointer, the `\|\c -.B \-fomit\-frame\-pointer\c -\&\|' option is turned on. On some machines other flags may also be turned on. -.TP -.B \-O2 -Optimize even more. Nearly all supported optimizations that do not -involve a space-speed tradeoff are performed. Loop unrolling and function -inlining are not done, for example. As compared to -.B \-O\c -\&, -this option increases both compilation time and the performance of the -generated code. -.TP -.B \-O3 -Optimize yet more. This turns on everything -.B \-O2 -does, along with also turning on -.B \-finline\-functions. -.TP -.B \-O0 -Do not optimize. -.Sp -If you use multiple -.B \-O -options, with or without level numbers, the last such option is the -one that is effective. -.PP -Options of the form `\|\c -.B \-f\c -.I flag\c -\&\c -\&\|' specify machine-independent -flags. Most flags have both positive and negative forms; the negative -form of `\|\c -.B \-ffoo\c -\&\|' would be `\|\c -.B \-fno\-foo\c -\&\|'. The following list shows -only one form\(em\&the one which is not the default. -You can figure out the other form by either removing `\|\c -.B no\-\c -\&\|' or -adding it. -.TP -.B \-ffloat\-store -Do not store floating point variables in registers. This -prevents undesirable excess precision on machines such as the -68000 where the floating registers (of the 68881) keep more -precision than a \c -.B double\c -\& is supposed to have. -.Sp -For most programs, the excess precision does only good, but a few -programs rely on the precise definition of IEEE floating point. -Use `\|\c -.B \-ffloat\-store\c -\&\|' for such programs. -.TP -.B \-fmemoize\-lookups -.TP -.B \-fsave\-memoized -Use heuristics to compile faster (C++ only). These heuristics are not -enabled by default, since they are only effective for certain input -files. Other input files compile more slowly. -.Sp -The first time the compiler must build a call to a member function (or -reference to a data member), it must (1) determine whether the class -implements member functions of that name; (2) resolve which member -function to call (which involves figuring out what sorts of type -conversions need to be made); and (3) check the visibility of the member -function to the caller. All of this adds up to slower compilation. -Normally, the second time a call is made to that member function (or -reference to that data member), it must go through the same lengthy -process again. This means that code like this -.Sp -\& cout << "This " << p << " has " << n << " legs.\en"; -.Sp -makes six passes through all three steps. By using a software cache, -a \*(lqhit\*(rq significantly reduces this cost. Unfortunately, using the -cache introduces another layer of mechanisms which must be implemented, -and so incurs its own overhead. `\|\c -.B \-fmemoize\-lookups\c -\&\|' enables -the software cache. -.Sp -Because access privileges (visibility) to members and member functions -may differ from one function context to the next, -.B g++ -may need to flush the cache. With the `\|\c -.B \-fmemoize\-lookups\c -\&\|' flag, the cache is flushed after every -function that is compiled. The `\|\c -\-fsave\-memoized\c -\&\|' flag enables the same software cache, but when the compiler -determines that the context of the last function compiled would yield -the same access privileges of the next function to compile, it -preserves the cache. -This is most helpful when defining many member functions for the same -class: with the exception of member functions which are friends of -other classes, each member function has exactly the same access -privileges as every other, and the cache need not be flushed. -.TP -.B \-fno\-default\-inline -Don't make member functions inline by default merely because they are -defined inside the class scope (C++ only). -.TP -.B \-fno\-defer\-pop -Always pop the arguments to each function call as soon as that -function returns. For machines which must pop arguments after a -function call, the compiler normally lets arguments accumulate on the -stack for several function calls and pops them all at once. -.TP -.B \-fforce\-mem -Force memory operands to be copied into registers before doing -arithmetic on them. This may produce better code by making all -memory references potential common subexpressions. When they are -not common subexpressions, instruction combination should -eliminate the separate register-load. I am interested in hearing -about the difference this makes. -.TP -.B \-fforce\-addr -Force memory address constants to be copied into registers before -doing arithmetic on them. This may produce better code just as -`\|\c -.B \-fforce\-mem\c -\&\|' may. I am interested in hearing about the -difference this makes. -.TP -.B \-fomit\-frame\-pointer -Don't keep the frame pointer in a register for functions that -don't need one. This avoids the instructions to save, set up and -restore frame pointers; it also makes an extra register available -in many functions. \c -.I It also makes debugging impossible on most machines\c -\&. -.Sp -On some machines, such as the Vax, this flag has no effect, because -the standard calling sequence automatically handles the frame pointer -and nothing is saved by pretending it doesn't exist. The -machine-description macro \c -.B FRAME_POINTER_REQUIRED\c -\& controls -whether a target machine supports this flag. -.TP -.B \-finline\-functions -Integrate all simple functions into their callers. The compiler -heuristically decides which functions are simple enough to be worth -integrating in this way. -.Sp -If all calls to a given function are integrated, and the function is -declared \c -.B static\c -\&, then GCC normally does not output the function as -assembler code in its own right. -.TP -.B \-fcaller\-saves -Enable values to be allocated in registers that will be clobbered by -function calls, by emitting extra instructions to save and restore the -registers around such calls. Such allocation is done only when it -seems to result in better code than would otherwise be produced. -.Sp -This option is enabled by default on certain machines, usually those -which have no call-preserved registers to use instead. -.TP -.B \-fkeep\-inline\-functions -Even if all calls to a given function are integrated, and the function -is declared \c -.B static\c -\&, nevertheless output a separate run-time -callable version of the function. -.TP -.B \-fno\-function\-cse -Do not put function addresses in registers; make each instruction that -calls a constant function contain the function's address explicitly. -.Sp -This option results in less efficient code, but some strange hacks -that alter the assembler output may be confused by the optimizations -performed when this option is not used. -.TP -.B \-fno\-peephole -Disable any machine-specific peephole optimizations. -.TP -.B \-ffast-math -This option allows GCC to violate some ANSI or IEEE rules/specifications -in the interest of optimizing code for speed. For example, it allows -the compiler to assume arguments to the \c -.B sqrt\c -\& function are -non-negative numbers. -.Sp -This option should never be turned on by any `\|\c -.B \-O\c -\&\|' option since -it can result in incorrect output for programs which depend on -an exact implementation of IEEE or ANSI rules/specifications for -math functions. -.PP -The following options control specific optimizations. The `\|\c -.B \-O2\c -\&\|' -option turns on all of these optimizations except `\|\c -.B \-funroll\-loops\c -\&\|' -and `\|\c -.B \-funroll\-all\-loops\c -\&\|'. -.PP -The `\|\c -.B \-O\c -\&\|' option usually turns on -the `\|\c -.B \-fthread\-jumps\c -\&\|' and `\|\c -.B \-fdelayed\-branch\c -\&\|' options, but -specific machines may change the default optimizations. -.PP -You can use the following flags in the rare cases when \*(lqfine-tuning\*(rq -of optimizations to be performed is desired. -.TP -.B \-fstrength\-reduce -Perform the optimizations of loop strength reduction and -elimination of iteration variables. -.TP -.B \-fthread\-jumps -Perform optimizations where we check to see if a jump branches to a -location where another comparison subsumed by the first is found. If -so, the first branch is redirected to either the destination of the -second branch or a point immediately following it, depending on whether -the condition is known to be true or false. -.TP -.B \-funroll\-loops -Perform the optimization of loop unrolling. This is only done for loops -whose number of iterations can be determined at compile time or run time. -.TP -.B \-funroll\-all\-loops -Perform the optimization of loop unrolling. This is done for all loops. -This usually makes programs run more slowly. -.TP -.B \-fcse\-follow\-jumps -In common subexpression elimination, scan through jump instructions -when the target of the jump is not reached by any other path. For -example, when CSE encounters an \c -.B if\c -\& statement with an -.B else\c -\& clause, CSE will follow the jump when the condition -tested is false. -.TP -.B \-fcse\-skip\-blocks -This is similar to `\|\c -.B \-fcse\-follow\-jumps\c -\&\|', but causes CSE to -follow jumps which conditionally skip over blocks. When CSE -encounters a simple \c -.B if\c -\& statement with no else clause, -`\|\c -.B \-fcse\-skip\-blocks\c -\&\|' causes CSE to follow the jump around the -body of the \c -.B if\c -\&. -.TP -.B \-frerun\-cse\-after\-loop -Re-run common subexpression elimination after loop optimizations has been -performed. -.TP -.B \-felide\-constructors -Elide constructors when this seems plausible (C++ only). With this -flag, GNU C++ initializes \c -.B y\c -\& directly from the call to \c -.B foo -without going through a temporary in the following code: -.Sp -A foo (); -A y = foo (); -.Sp -Without this option, GNU C++ first initializes \c -.B y\c -\& by calling the -appropriate constructor for type \c -.B A\c -\&; then assigns the result of -.B foo\c -\& to a temporary; and, finally, replaces the initial value of -`\|\c -.B y\c -\&\|' with the temporary. -.Sp -The default behavior (`\|\c -.B \-fno\-elide\-constructors\c -\&\|') is specified by -the draft ANSI C++ standard. If your program's constructors have side -effects, using `\|\c -.B \-felide-constructors\c -\&\|' can make your program act -differently, since some constructor calls may be omitted. -.TP -.B \-fexpensive\-optimizations -Perform a number of minor optimizations that are relatively expensive. -.TP -.B \-fdelayed\-branch -If supported for the target machine, attempt to reorder instructions -to exploit instruction slots available after delayed branch -instructions. -.TP -.B \-fschedule\-insns -If supported for the target machine, attempt to reorder instructions to -eliminate execution stalls due to required data being unavailable. This -helps machines that have slow floating point or memory load instructions -by allowing other instructions to be issued until the result of the load -or floating point instruction is required. -.TP -.B \-fschedule\-insns2 -Similar to `\|\c -.B \-fschedule\-insns\c -\&\|', but requests an additional pass of -instruction scheduling after register allocation has been done. This is -especially useful on machines with a relatively small number of -registers and where memory load instructions take more than one cycle. -.SH TARGET OPTIONS -By default, GNU CC compiles code for the same type of machine that you -are using. However, it can also be installed as a cross-compiler, to -compile for some other type of machine. In fact, several different -configurations of GNU CC, for different target machines, can be -installed side by side. Then you specify which one to use with the -`\|\c -.B \-b\c -\&\|' option. -.PP -In addition, older and newer versions of GNU CC can be installed side -by side. One of them (probably the newest) will be the default, but -you may sometimes wish to use another. -.TP -.BI "\-b " "machine" -The argument \c -.I machine\c -\& specifies the target machine for compilation. -This is useful when you have installed GNU CC as a cross-compiler. -.Sp -The value to use for \c -.I machine\c -\& is the same as was specified as the -machine type when configuring GNU CC as a cross-compiler. For -example, if a cross-compiler was configured with `\|\c -.B configure -i386v\c -\&\|', meaning to compile for an 80386 running System V, then you -would specify `\|\c -.B \-b i386v\c -\&\|' to run that cross compiler. -.Sp -When you do not specify `\|\c -.B \-b\c -\&\|', it normally means to compile for -the same type of machine that you are using. -.TP -.BI "\-V " "version" -The argument \c -.I version\c -\& specifies which version of GNU CC to run. -This is useful when multiple versions are installed. For example, -.I version\c -\& might be `\|\c -.B 2.0\c -\&\|', meaning to run GNU CC version 2.0. -.Sp -The default version, when you do not specify `\|\c -.B \-V\c -\&\|', is controlled -by the way GNU CC is installed. Normally, it will be a version that -is recommended for general use. -.SH MACHINE DEPENDENT OPTIONS -Each of the target machine types can have its own special options, -starting with `\|\c -.B \-m\c -\&\|', to choose among various hardware models or -configurations\(em\&for example, 68010 vs 68020, floating coprocessor or -none. A single installed version of the compiler can compile for any -model or configuration, according to the options specified. -.PP -Some configurations of the compiler also support additional special -options, usually for command-line compatibility with other compilers on -the same platform. -.PP -These are the `\|\c -.B \-m\c -\&\|' options defined for the 68000 series: -.TP -.B \-m68000 -.TP -.B \-mc68000 -Generate output for a 68000. This is the default when the compiler is -configured for 68000-based systems. -.TP -.B \-m68020 -.TP -.B \-mc68020 -Generate output for a 68020 (rather than a 68000). This is the -default when the compiler is configured for 68020-based systems. -.TP -.B \-m68881 -Generate output containing 68881 instructions for floating point. -This is the default for most 68020-based systems unless -.B \-nfp -was specified when the compiler was configured. -.TP -.B \-m68030 -Generate output for a 68030. This is the default when the compiler is -configured for 68030-based systems. -.TP -.B \-m68040 -Generate output for a 68040. This is the default when the compiler is -configured for 68040-based systems. -.TP -.B \-m68020\-40 -Generate output for a 68040, without using any of the new instructions. -This results in code which can run relatively efficiently on either a -68020/68881 or a 68030 or a 68040. -.TP -.B \-mfpa -Generate output containing Sun FPA instructions for floating point. -.TP -.B \-msoft\-float -Generate output containing library calls for floating point. -.I -WARNING: -the requisite libraries are not part of GNU CC. Normally the -facilities of the machine's usual C compiler are used, but this can't -be done directly in cross-compilation. You must make your own -arrangements to provide suitable library functions for cross-compilation. -.TP -.B \-mshort -Consider type \c -.B int\c -\& to be 16 bits wide, like \c -.B short int\c -\&. -.TP -.B \-mnobitfield -Do not use the bit-field instructions. `\|\c -.B \-m68000\c -\&\|' implies -`\|\c -.B \-mnobitfield\c -\&\|'. -.TP -.B \-mbitfield -Do use the bit-field instructions. `\|\c -.B \-m68020\c -\&\|' implies -`\|\c -.B \-mbitfield\c -\&\|'. This is the default if you use the unmodified -sources. -.TP -.B \-mrtd -Use a different function-calling convention, in which functions -that take a fixed number of arguments return with the \c -.B rtd -instruction, which pops their arguments while returning. This -saves one instruction in the caller since there is no need to pop -the arguments there. -.Sp -This calling convention is incompatible with the one normally -used on Unix, so you cannot use it if you need to call libraries -compiled with the Unix compiler. -.Sp -Also, you must provide function prototypes for all functions that -take variable numbers of arguments (including \c -.B printf\c -\&); -otherwise incorrect code will be generated for calls to those -functions. -.Sp -In addition, seriously incorrect code will result if you call a -function with too many arguments. (Normally, extra arguments are -harmlessly ignored.) -.Sp -The \c -.B rtd\c -\& instruction is supported by the 68010 and 68020 -processors, but not by the 68000. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the Vax: -.TP -.B \-munix -Do not output certain jump instructions (\c -.B aobleq\c -\& and so on) -that the Unix assembler for the Vax cannot handle across long -ranges. -.TP -.B \-mgnu -Do output those jump instructions, on the assumption that you -will assemble with the GNU assembler. -.TP -.B \-mg -Output code for g-format floating point numbers instead of d-format. -.PP -These `\|\c -.B \-m\c -\&\|' switches are supported on the SPARC: -.PP -.B \-mfpu -.TP -.B \-mhard\-float -Generate output containing floating point instructions. This is the -default. -.PP -.B \-mno\-fpu -.TP -.B \-msoft\-float -Generate output containing library calls for floating point. -.I Warning: -there is no GNU floating-point library for SPARC. -Normally the facilities of the machine's usual C compiler are used, but -this cannot be done directly in cross-compilation. You must make your -own arrangements to provide suitable library functions for -cross-compilation. -.Sp -.B \-msoft\-float -changes the calling convention in the output file; -therefore, it is only useful if you compile -.I all -of a program with this option. -.PP -.B \-mno\-epilogue -.TP -.B \-mepilogue -With -.B \-mepilogue -(the default), the compiler always emits code for -function exit at the end of each function. Any function exit in -the middle of the function (such as a return statement in C) will -generate a jump to the exit code at the end of the function. -.Sp -With -.BR \-mno\-epilogue , -the compiler tries to emit exit code inline at every function exit. -.PP -.B \-mno\-v8 -.TP -.B \-mv8 -.TP -.B \-msparclite -These three options select variations on the SPARC architecture. -.Sp -By default (unless specifically configured for the Fujitsu SPARClite), -GCC generates code for the v7 variant of the SPARC architecture. -.Sp -.B \-mv8 -will give you SPARC v8 code. The only difference from v7 -code is that the compiler emits the integer multiply and integer -divide instructions which exist in SPARC v8 but not in SPARC v7. -.Sp -.B \-msparclite -will give you SPARClite code. This adds the integer -multiply, integer divide step and scan (ffs) instructions which -exist in SPARClite but not in SPARC v7. -.PP -.B \-mcypress -.TP -.B \-msupersparc -These two options select the processor for which the code is optimised. -.Sp -With -.B \-mcypress -(the default), the compiler optimises code for the Cypress CY7C602 chip, as -used in the SparcStation/SparcServer 3xx series. This is also appropriate for -the older SparcStation 1, 2, IPX etc. -.Sp -With -.B \-msupersparc -the compiler optimises code for the SuperSparc cpu, as used in the SparcStation -10, 1000 and 2000 series. This flag also enables use of the full SPARC v8 -instruction set. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the Convex: -.TP -.B \-mc1 -Generate output for a C1. This is the default when the compiler is -configured for a C1. -.TP -.B \-mc2 -Generate output for a C2. This is the default when the compiler is -configured for a C2. -.TP -.B \-margcount -Generate code which puts an argument count in the word preceding each -argument list. Some nonportable Convex and Vax programs need this word. -(Debuggers don't, except for functions with variable-length argument -lists; this info is in the symbol table.) -.TP -.B \-mnoargcount -Omit the argument count word. This is the default if you use the -unmodified sources. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the AMD Am29000: -.TP -.B \-mdw -Generate code that assumes the DW bit is set, i.e., that byte and -halfword operations are directly supported by the hardware. This is the -default. -.TP -.B \-mnodw -Generate code that assumes the DW bit is not set. -.TP -.B \-mbw -Generate code that assumes the system supports byte and halfword write -operations. This is the default. -.TP -.B \-mnbw -Generate code that assumes the systems does not support byte and -halfword write operations. This implies `\|\c -.B \-mnodw\c -\&\|'. -.TP -.B \-msmall -Use a small memory model that assumes that all function addresses are -either within a single 256 KB segment or at an absolute address of less -than 256K. This allows the \c -.B call\c -\& instruction to be used instead -of a \c -.B const\c -\&, \c -.B consth\c -\&, \c -.B calli\c -\& sequence. -.TP -.B \-mlarge -Do not assume that the \c -.B call\c -\& instruction can be used; this is the -default. -.TP -.B \-m29050 -Generate code for the Am29050. -.TP -.B \-m29000 -Generate code for the Am29000. This is the default. -.TP -.B \-mkernel\-registers -Generate references to registers \c -.B gr64-gr95\c -\& instead of -.B gr96-gr127\c -\&. This option can be used when compiling kernel code -that wants a set of global registers disjoint from that used by -user-mode code. -.Sp -Note that when this option is used, register names in `\|\c -.B \-f\c -\&\|' flags -must use the normal, user-mode, names. -.TP -.B \-muser\-registers -Use the normal set of global registers, \c -.B gr96-gr127\c -\&. This is the -default. -.TP -.B \-mstack\-check -Insert a call to \c -.B _\|_msp_check\c -\& after each stack adjustment. This -is often used for kernel code. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for Motorola 88K architectures: -.TP -.B \-m88000 -Generate code that works well on both the m88100 and the -m88110. -.TP -.B \-m88100 -Generate code that works best for the m88100, but that also -runs on the m88110. -.TP -.B \-m88110 -Generate code that works best for the m88110, and may not run -on the m88100. -.TP -.B \-midentify\-revision -Include an \c -.B ident\c -\& directive in the assembler output recording the -source file name, compiler name and version, timestamp, and compilation -flags used. -.TP -.B \-mno\-underscores -In assembler output, emit symbol names without adding an underscore -character at the beginning of each name. The default is to use an -underscore as prefix on each name. -.TP -.B \-mno\-check\-zero\-division -.TP -.B \-mcheck\-zero\-division -Early models of the 88K architecture had problems with division by zero; -in particular, many of them didn't trap. Use these options to avoid -including (or to include explicitly) additional code to detect division -by zero and signal an exception. All GCC configurations for the 88K use -`\|\c -.B \-mcheck\-zero\-division\c -\&\|' by default. -.TP -.B \-mocs\-debug\-info -.TP -.B \-mno\-ocs\-debug\-info -Include (or omit) additional debugging information (about -registers used in each stack frame) as specified in the 88Open Object -Compatibility Standard, \*(lqOCS\*(rq. This extra information is not needed -by GDB. The default for DG/UX, SVr4, and Delta 88 SVr3.2 is to -include this information; other 88k configurations omit this information -by default. -.TP -.B \-mocs\-frame\-position -.TP -.B \-mno\-ocs\-frame\-position -Force (or do not require) register values to be stored in a particular -place in stack frames, as specified in OCS. The DG/UX, Delta88 SVr3.2, -and BCS configurations use `\|\c -.B \-mocs\-frame\-position\c -\&\|'; other 88k -configurations have the default `\|\c -.B \-mno\-ocs\-frame\-position\c -\&\|'. -.TP -.B \-moptimize\-arg\-area -.TP -.B \-mno\-optimize\-arg\-area -Control how to store function arguments in stack frames. -`\|\c -.B \-moptimize\-arg\-area\c -\&\|' saves space, but may break some -debuggers (not GDB). `\|\c -.B \-mno\-optimize\-arg\-area\c -\&\|' conforms better to -standards. By default GCC does not optimize the argument area. -.TP -.BI "\-mshort\-data\-" "num" -.I num -Generate smaller data references by making them relative to \c -.B r0\c -\&, -which allows loading a value using a single instruction (rather than the -usual two). You control which data references are affected by -specifying \c -.I num\c -\& with this option. For example, if you specify -`\|\c -.B \-mshort\-data\-512\c -\&\|', then the data references affected are those -involving displacements of less than 512 bytes. -`\|\c -.B \-mshort\-data\-\c -.I num\c -\&\c -\&\|' is not effective for \c -.I num\c -\& greater -than 64K. -.PP -.B \-mserialize-volatile -.TP -.B \-mno-serialize-volatile -Do, or do not, generate code to guarantee sequential consistency of -volatile memory references. -.Sp -GNU CC always guarantees consistency by default, for the preferred -processor submodel. How this is done depends on the submodel. -.Sp -The m88100 processor does not reorder memory references and so always -provides sequential consistency. If you use `\|\c -.B \-m88100\c -\&\|', GNU CC does -not generate any special instructions for sequential consistency. -.Sp -The order of memory references made by the m88110 processor does not -always match the order of the instructions requesting those references. -In particular, a load instruction may execute before a preceding store -instruction. Such reordering violates sequential consistency of -volatile memory references, when there are multiple processors. When -you use `\|\c -.B \-m88000\c -\&\|' or `\|\c -.B \-m88110\c -\&\|', GNU CC generates special -instructions when appropriate, to force execution in the proper order. -.Sp -The extra code generated to guarantee consistency may affect the -performance of your application. If you know that you can safely forgo -this guarantee, you may use the option `\|\c -.B \-mno-serialize-volatile\c -\&\|'. -.Sp -If you use the `\|\c -.B \-m88100\c -\&\|' option but require sequential consistency -when running on the m88110 processor, you should use -`\|\c -.B \-mserialize-volatile\c -\&\|'. -.PP -.B \-msvr4 -.TP -.B \-msvr3 -Turn on (`\|\c -.B \-msvr4\c -\&\|') or off (`\|\c -.B \-msvr3\c -\&\|') compiler extensions -related to System V release 4 (SVr4). This controls the following: -.TP -\ \ \ \(bu -Which variant of the assembler syntax to emit (which you can select -independently using `\|\c -.B \-mversion\-03.00\c -\&\|'). -.TP -\ \ \ \(bu -`\|\c -.B \-msvr4\c -\&\|' makes the C preprocessor recognize `\|\c -.B #pragma weak\c -\&\|' -.TP -\ \ \ \(bu -`\|\c -.B \-msvr4\c -\&\|' makes GCC issue additional declaration directives used in -SVr4. -.PP -`\|\c -.B \-msvr3\c -\&\|' is the default for all m88K configurations except -the SVr4 configuration. -.TP -.B \-mtrap\-large\-shift -.TP -.B \-mhandle\-large\-shift -Include code to detect bit-shifts of more than 31 bits; respectively, -trap such shifts or emit code to handle them properly. By default GCC -makes no special provision for large bit shifts. -.TP -.B \-muse\-div\-instruction -Very early models of the 88K architecture didn't have a divide -instruction, so GCC avoids that instruction by default. Use this option -to specify that it's safe to use the divide instruction. -.TP -.B \-mversion\-03.00 -In the DG/UX configuration, there are two flavors of SVr4. This option -modifies -.B \-msvr4 -to select whether the hybrid-COFF or real-ELF -flavor is used. All other configurations ignore this option. -.TP -.B \-mwarn\-passed\-structs -Warn when a function passes a struct as an argument or result. -Structure-passing conventions have changed during the evolution of the C -language, and are often the source of portability problems. By default, -GCC issues no such warning. -.PP -These options are defined for the IBM RS6000: -.PP -.B \-mfp\-in\-toc -.TP -.B \-mno\-fp\-in\-toc -Control whether or not floating-point constants go in the Table of -Contents (TOC), a table of all global variable and function addresses. By -default GCC puts floating-point constants there; if the TOC overflows, -`\|\c -.B \-mno\-fp\-in\-toc\c -\&\|' will reduce the size of the TOC, which may avoid -the overflow. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the IBM RT PC: -.TP -.B \-min\-line\-mul -Use an in-line code sequence for integer multiplies. This is the -default. -.TP -.B \-mcall\-lib\-mul -Call \c -.B lmul$$\c -\& for integer multiples. -.TP -.B \-mfull\-fp\-blocks -Generate full-size floating point data blocks, including the minimum -amount of scratch space recommended by IBM. This is the default. -.TP -.B \-mminimum\-fp\-blocks -Do not include extra scratch space in floating point data blocks. This -results in smaller code, but slower execution, since scratch space must -be allocated dynamically. -.TP -.B \-mfp\-arg\-in\-fpregs -Use a calling sequence incompatible with the IBM calling convention in -which floating point arguments are passed in floating point registers. -Note that \c -.B varargs.h\c -\& and \c -.B stdargs.h\c -\& will not work with -floating point operands if this option is specified. -.TP -.B \-mfp\-arg\-in\-gregs -Use the normal calling convention for floating point arguments. This is -the default. -.TP -.B \-mhc\-struct\-return -Return structures of more than one word in memory, rather than in a -register. This provides compatibility with the MetaWare HighC (hc) -compiler. Use `\|\c -.B \-fpcc\-struct\-return\c -\&\|' for compatibility with the -Portable C Compiler (pcc). -.TP -.B \-mnohc\-struct\-return -Return some structures of more than one word in registers, when -convenient. This is the default. For compatibility with the -IBM-supplied compilers, use either `\|\c -.B \-fpcc\-struct\-return\c -\&\|' or -`\|\c -.B \-mhc\-struct\-return\c -\&\|'. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the MIPS family of computers: -.TP -.BI "\-mcpu=" "cpu-type" -Assume the defaults for the machine type -.I cpu-type -when -scheduling instructions. The default -.I cpu-type -is -.BR default , -which picks the longest cycles times for any of the machines, in order -that the code run at reasonable rates on all MIPS cpu's. Other -choices for -.I cpu-type -are -.BR r2000 , -.BR r3000 , -.BR r4000 , -and -.BR r6000 . -While picking a specific -.I cpu-type -will schedule things appropriately for that particular chip, the -compiler will not generate any code that does not meet level 1 of the -MIPS ISA (instruction set architecture) without the -.B \-mips2 -or -.B \-mips3 -switches being used. -.TP -.B \-mips2 -Issue instructions from level 2 of the MIPS ISA (branch likely, square -root instructions). The -.B \-mcpu=r4000 -or -.B \-mcpu=r6000 -switch must be used in conjunction with -.BR \-mips2 . -.TP -.B \-mips3 -Issue instructions from level 3 of the MIPS ISA (64 bit instructions). -The -.B \-mcpu=r4000 -switch must be used in conjunction with -.BR \-mips2 . -.TP -.B \-mint64 -.TP -.B \-mlong64 -.TP -.B \-mlonglong128 -These options don't work at present. -.TP -.B \-mmips\-as -Generate code for the MIPS assembler, and invoke -.B mips\-tfile -to add normal debug information. This is the default for all -platforms except for the OSF/1 reference platform, using the OSF/rose -object format. If any of the -.BR \-ggdb , -.BR \-gstabs , -or -.B \-gstabs+ -switches are used, the -.B mips\-tfile -program will encapsulate the stabs within MIPS ECOFF. -.TP -.B \-mgas -Generate code for the GNU assembler. This is the default on the OSF/1 -reference platform, using the OSF/rose object format. -.TP -.B \-mrnames -.TP -.B \-mno\-rnames -The -.B \-mrnames -switch says to output code using the MIPS software names for the -registers, instead of the hardware names (ie, -.B a0 -instead of -.BR $4 ). -The GNU assembler does not support the -.B \-mrnames -switch, and the MIPS assembler will be instructed to run the MIPS C -preprocessor over the source file. The -.B \-mno\-rnames -switch is default. -.TP -.B \-mgpopt -.TP -.B \-mno\-gpopt -The -.B \-mgpopt -switch says to write all of the data declarations before the -instructions in the text section, to all the MIPS assembler to -generate one word memory references instead of using two words for -short global or static data items. This is on by default if -optimization is selected. -.TP -.B \-mstats -.TP -.B \-mno\-stats -For each non-inline function processed, the -.B \-mstats -switch causes the compiler to emit one line to the standard error file -to print statistics about the program (number of registers saved, -stack size, etc.). -.TP -.B \-mmemcpy -.TP -.B \-mno\-memcpy -The -.B \-mmemcpy -switch makes all block moves call the appropriate string function -.RB ( memcpy -or -.BR bcopy ) -instead of possibly generating inline code. -.TP -.B \-mmips\-tfile -.TP -.B \-mno\-mips\-tfile -The -.B \-mno\-mips\-tfile -switch causes the compiler not postprocess the object file with the -.B mips\-tfile -program, after the MIPS assembler has generated it to add debug -support. If -.B mips\-tfile -is not run, then no local variables will be available to the debugger. -In addition, -.B stage2 -and -.B stage3 -objects will have the temporary file names passed to the assembler -embedded in the object file, which means the objects will not compare -the same. -.TP -.B \-msoft\-float -Generate output containing library calls for floating point. -.I -WARNING: -the requisite libraries are not part of GNU CC. Normally the -facilities of the machine's usual C compiler are used, but this can't -be done directly in cross-compilation. You must make your own -arrangements to provide suitable library functions for cross-compilation. -.TP -.B \-mhard\-float -Generate output containing floating point instructions. This is the -default if you use the unmodified sources. -.TP -.B \-mfp64 -Assume that the -.B FR -bit in the status word is on, and that there are 32 64-bit floating -point registers, instead of 32 32-bit floating point registers. You -must also specify the -.B \-mcpu=r4000 -and -.B \-mips3 -switches. -.TP -.B \-mfp32 -Assume that there are 32 32-bit floating point registers. This is the -default. -.PP -.B \-mabicalls -.TP -.B \-mno\-abicalls -Emit (or do not emit) the -.BR \&.abicalls , -.BR \&.cpload , -and -.B \&.cprestore -pseudo operations that some System V.4 ports use for position -independent code. -.TP -.B \-mhalf\-pic -.TP -.B \-mno\-half\-pic -The -.B \-mhalf\-pic -switch says to put pointers to extern references into the data section -and load them up, rather than put the references in the text section. -This option does not work at present. -.B -.BI \-G num -Put global and static items less than or equal to -.I num -bytes into the small data or bss sections instead of the normal data -or bss section. This allows the assembler to emit one word memory -reference instructions based on the global pointer -.RB ( gp -or -.BR $28 ), -instead of the normal two words used. By default, -.I num -is 8 when the MIPS assembler is used, and 0 when the GNU -assembler is used. The -.BI \-G num -switch is also passed to the assembler and linker. All modules should -be compiled with the same -.BI \-G num -value. -.TP -.B \-nocpp -Tell the MIPS assembler to not run its preprocessor over user -assembler files (with a `\|\c -.B .s\c -\&\|' suffix) when assembling them. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the Intel 80386 family of computers: -.B \-m486 -.TP -.B \-mno\-486 -Control whether or not code is optimized for a 486 instead of an -386. Code generated for a 486 will run on a 386 and vice versa. -.TP -.B \-msoft\-float -Generate output containing library calls for floating point. -.I Warning: -the requisite libraries are not part of GNU CC. -Normally the facilities of the machine's usual C compiler are used, but -this can't be done directly in cross-compilation. You must make your -own arrangements to provide suitable library functions for -cross-compilation. -.Sp -On machines where a function returns floating point results in the 80387 -register stack, some floating point opcodes may be emitted even if -`\|\c -.B \-msoft-float\c -\&\|' is used. -.TP -.B \-mno-fp-ret-in-387 -Do not use the FPU registers for return values of functions. -.Sp -The usual calling convention has functions return values of types -.B float\c -\& and \c -.B double\c -\& in an FPU register, even if there -is no FPU. The idea is that the operating system should emulate -an FPU. -.Sp -The option `\|\c -.B \-mno-fp-ret-in-387\c -\&\|' causes such values to be returned -in ordinary CPU registers instead. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the HPPA family of computers: -.TP -.B \-mpa-risc-1-0 -Generate code for a PA 1.0 processor. -.TP -.B \-mpa-risc-1-1 -Generate code for a PA 1.1 processor. -.TP -.B \-mkernel -Generate code which is suitable for use in kernels. Specifically, avoid -.B add\c -\& instructions in which one of the arguments is the DP register; -generate \c -.B addil\c -\& instructions instead. This avoids a rather serious -bug in the HP-UX linker. -.TP -.B \-mshared-libs -Generate code that can be linked against HP-UX shared libraries. This option -is not fully function yet, and is not on by default for any PA target. Using -this option can cause incorrect code to be generated by the compiler. -.TP -.B \-mno-shared-libs -Don't generate code that will be linked against shared libraries. This is -the default for all PA targets. -.TP -.B \-mlong-calls -Generate code which allows calls to functions greater than 256K away from -the caller when the caller and callee are in the same source file. Do -not turn this option on unless code refuses to link with \*(lqbranch out of -range errors\*('' from the linker. -.TP -.B \-mdisable-fpregs -Prevent floating point registers from being used in any manner. This is -necessary for compiling kernels which perform lazy context switching of -floating point registers. If you use this option and attempt to perform -floating point operations, the compiler will abort. -.TP -.B \-mdisable-indexing -Prevent the compiler from using indexing address modes. This avoids some -rather obscure problems when compiling MIG generated code under MACH. -.TP -.B \-mtrailing-colon -Add a colon to the end of label definitions (for ELF assemblers). -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the Intel 80960 family of computers: -.TP -.BI "\-m" "cpu-type" -Assume the defaults for the machine type -.I cpu-type -for instruction and addressing-mode availability and alignment. -The default -.I cpu-type -is -.BR kb ; -other choices are -.BR ka , -.BR mc , -.BR ca , -.BR cf , -.BR sa , -and -.BR sb . -.TP -.B \-mnumerics -.TP -.B \-msoft\-float -The -.B \-mnumerics -option indicates that the processor does support -floating-point instructions. The -.B \-msoft\-float -option indicates -that floating-point support should not be assumed. -.TP -.B \-mleaf\-procedures -.TP -.B \-mno\-leaf\-procedures -Do (or do not) attempt to alter leaf procedures to be callable with the -.I bal -instruction as well as -.IR call . -This will result in more -efficient code for explicit calls when the -.I bal -instruction can be -substituted by the assembler or linker, but less efficient code in other -cases, such as calls via function pointers, or using a linker that doesn't -support this optimization. -.TP -.B \-mtail\-call -.TP -.B \-mno\-tail\-call -Do (or do not) make additional attempts (beyond those of the -machine-independent portions of the compiler) to optimize tail-recursive -calls into branches. You may not want to do this because the detection of -cases where this is not valid is not totally complete. The default is -.BR \-mno\-tail\-call . -.TP -.B \-mcomplex\-addr -.TP -.B \-mno\-complex\-addr -Assume (or do not assume) that the use of a complex addressing mode is a -win on this implementation of the i960. Complex addressing modes may not -be worthwhile on the K-series, but they definitely are on the C-series. -The default is currently -.B \-mcomplex\-addr -for all processors except -the CB and CC. -.TP -.B \-mcode\-align -.TP -.B \-mno\-code\-align -Align code to 8-byte boundaries for faster fetching (or don't bother). -Currently turned on by default for C-series implementations only. -.TP -.B \-mic\-compat -.TP -.B \-mic2.0\-compat -.TP -.B \-mic3.0\-compat -Enable compatibility with iC960 v2.0 or v3.0. -.TP -.B \-masm\-compat -.TP -.B \-mintel\-asm -Enable compatibility with the iC960 assembler. -.TP -.B \-mstrict\-align -.TP -.B \-mno\-strict\-align -Do not permit (do permit) unaligned accesses. -.TP -.B \-mold\-align -Enable structure-alignment compatibility with Intel's gcc release version -1.3 (based on gcc 1.37). Currently this is buggy in that -.B #pragma align 1 -is always assumed as well, and cannot be turned off. -.PP -These `\|\c -.B \-m\c -\&\|' options are defined for the DEC Alpha implementations: -.TP -.B \-mno-soft-float -.TP -.B \-msoft-float -Use (do not use) the hardware floating-point instructions for -floating-point operations. When \c -.B \-msoft-float\c -\& is specified, -functions in `\|\c -.B libgcc1.c\c -\&\|' will be used to perform floating-point -operations. Unless they are replaced by routines that emulate the -floating-point operations, or compiled in such a way as to call such -emulations routines, these routines will issue floating-point -operations. If you are compiling for an Alpha without floating-point -operations, you must ensure that the library is built so as not to call -them. -.Sp -Note that Alpha implementations without floating-point operations are -required to have floating-point registers. -.TP -.B \-mfp-reg -.TP -.B \-mno-fp-regs -Generate code that uses (does not use) the floating-point register set. -.B \-mno-fp-regs\c -\& implies \c -.B \-msoft-float\c -\&. If the floating-point -register set is not used, floating point operands are passed in integer -registers as if they were integers and floating-point results are passed -in $0 instead of $f0. This is a non-standard calling sequence, so any -function with a floating-point argument or return value called by code -compiled with \c -.B \-mno-fp-regs\c -\& must also be compiled with that -option. -.Sp -A typical use of this option is building a kernel that does not use, -and hence need not save and restore, any floating-point registers. -.PP -These additional options are available on System V Release 4 for -compatibility with other compilers on those systems: -.TP -.B \-G -On SVr4 systems, \c -.B gcc\c -\& accepts the option `\|\c -.B \-G\c -\&\|' (and passes -it to the system linker), for compatibility with other compilers. -However, we suggest you use `\|\c -.B \-symbolic\c -\&\|' or `\|\c -.B \-shared\c -\&\|' as -appropriate, instead of supplying linker options on the \c -.B gcc -command line. -.TP -.B \-Qy -Identify the versions of each tool used by the compiler, in a -.B .ident\c -\& assembler directive in the output. -.TP -.B \-Qn -Refrain from adding \c -.B .ident\c -\& directives to the output file (this is -the default). -.TP -.BI "\-YP," "dirs" -Search the directories \c -.I dirs\c -\&, and no others, for libraries -specified with `\|\c -.B \-l\c -\&\|'. You can separate directory entries in -.I dirs\c -\& from one another with colons. -.TP -.BI "\-Ym," "dir" -Look in the directory \c -.I dir\c -\& to find the M4 preprocessor. -The assembler uses this option. -.SH CODE GENERATION OPTIONS -These machine-independent options control the interface conventions -used in code generation. -.PP -Most of them begin with `\|\c -\-f\c -\&\|'. These options have both positive and negative forms; the negative form -of `\|\c -.B \-ffoo\c -\&\|' would be `\|\c -.B \-fno\-foo\c -\&\|'. In the table below, only -one of the forms is listed\(em\&the one which is not the default. You -can figure out the other form by either removing `\|\c -.B no\-\c -\&\|' or adding -it. -.TP -.B \-fnonnull\-objects -Assume that objects reached through references are not null -(C++ only). -.Sp -Normally, GNU C++ makes conservative assumptions about objects reached -through references. For example, the compiler must check that \c -.B a -is not null in code like the following: -.Sp -obj &a = g (); -a.f (2); -.Sp -Checking that references of this sort have non-null values requires -extra code, however, and it is unnecessary for many programs. You can -use `\|\c -.B \-fnonnull-objects\c -\&\|' to omit the checks for null, if your -program doesn't require checking. -.TP -.B \-fpcc\-struct\-return -Use the same convention for returning \c -.B struct\c -\& and \c -.B union -values that is used by the usual C compiler on your system. This -convention is less efficient for small structures, and on many -machines it fails to be reentrant; but it has the advantage of -allowing intercallability between GCC-compiled code and PCC-compiled -code. -.TP -.B \-freg\-struct\-return -Use the convention that -.B struct -and -.B union -values are returned in registers when possible. This is more -efficient for small structures than -.BR \-fpcc\-struct\-return . -.Sp -If you specify neither -.B \-fpcc\-struct\-return -nor -.BR \-freg\-struct\-return , -GNU CC defaults to whichever convention is standard for the target. -If there is no standard convention, GNU CC defaults to -.BR \-fpcc\-struct\-return . -.TP -.B \-fshort\-enums -Allocate to an \c -.B enum\c -\& type only as many bytes as it needs for the -declared range of possible values. Specifically, the \c -.B enum\c -\& type -will be equivalent to the smallest integer type which has enough room. -.TP -.B \-fshort\-double -Use the same size for -.B double -as for -.B float -\&. -.TP -.B \-fshared\-data -Requests that the data and non-\c -.B const\c -\& variables of this -compilation be shared data rather than private data. The distinction -makes sense only on certain operating systems, where shared data is -shared between processes running the same program, while private data -exists in one copy per process. -.TP -.B \-fno\-common -Allocate even uninitialized global variables in the bss section of the -object file, rather than generating them as common blocks. This has the -effect that if the same variable is declared (without \c -.B extern\c -\&) in -two different compilations, you will get an error when you link them. -The only reason this might be useful is if you wish to verify that the -program will work on other systems which always work this way. -.TP -.B \-fno\-ident -Ignore the `\|\c -.B #ident\c -\&\|' directive. -.TP -.B \-fno\-gnu\-linker -Do not output global initializations (such as C++ constructors and -destructors) in the form used by the GNU linker (on systems where the GNU -linker is the standard method of handling them). Use this option when -you want to use a non-GNU linker, which also requires using the -.B collect2\c -\& program to make sure the system linker includes -constructors and destructors. (\c -.B collect2\c -\& is included in the GNU CC -distribution.) For systems which \c -.I must\c -\& use \c -.B collect2\c -\&, the -compiler driver \c -.B gcc\c -\& is configured to do this automatically. -.TP -.B \-finhibit-size-directive -Don't output a \c -.B .size\c -\& assembler directive, or anything else that -would cause trouble if the function is split in the middle, and the -two halves are placed at locations far apart in memory. This option is -used when compiling `\|\c -.B crtstuff.c\c -\&\|'; you should not need to use it -for anything else. -.TP -.B \-fverbose-asm -Put extra commentary information in the generated assembly code to -make it more readable. This option is generally only of use to those -who actually need to read the generated assembly code (perhaps while -debugging the compiler itself). -.TP -.B \-fvolatile -Consider all memory references through pointers to be volatile. -.TP -.B \-fvolatile\-global -Consider all memory references to extern and global data items to -be volatile. -.TP -.B \-fpic -If supported for the target machines, generate position-independent code, -suitable for use in a shared library. -.TP -.B \-fPIC -If supported for the target machine, emit position-independent code, -suitable for dynamic linking, even if branches need large displacements. -.TP -.BI "\-ffixed\-" "reg" -Treat the register named \c -.I reg\c -\& as a fixed register; generated code -should never refer to it (except perhaps as a stack pointer, frame -pointer or in some other fixed role). -.Sp -.I reg\c -\& must be the name of a register. The register names accepted -are machine-specific and are defined in the \c -.B REGISTER_NAMES -macro in the machine description macro file. -.Sp -This flag does not have a negative form, because it specifies a -three-way choice. -.TP -.BI "\-fcall\-used\-" "reg" -Treat the register named \c -.I reg\c -\& as an allocable register that is -clobbered by function calls. It may be allocated for temporaries or -variables that do not live across a call. Functions compiled this way -will not save and restore the register \c -.I reg\c -\&. -.Sp -Use of this flag for a register that has a fixed pervasive role in the -machine's execution model, such as the stack pointer or frame pointer, -will produce disastrous results. -.Sp -This flag does not have a negative form, because it specifies a -three-way choice. -.TP -.BI "\-fcall\-saved\-" "reg" -Treat the register named \c -.I reg\c -\& as an allocable register saved by -functions. It may be allocated even for temporaries or variables that -live across a call. Functions compiled this way will save and restore -the register \c -.I reg\c -\& if they use it. -.Sp -Use of this flag for a register that has a fixed pervasive role in the -machine's execution model, such as the stack pointer or frame pointer, -will produce disastrous results. -.Sp -A different sort of disaster will result from the use of this flag for -a register in which function values may be returned. -.Sp -This flag does not have a negative form, because it specifies a -three-way choice. -.SH PRAGMAS -Two `\|\c -.B #pragma\c -\&\|' directives are supported for GNU C++, to permit using the same -header file for two purposes: as a definition of interfaces to a given -object class, and as the full definition of the contents of that object class. -.TP -.B #pragma interface -(C++ only.) -Use this directive in header files that define object classes, to save -space in most of the object files that use those classes. Normally, -local copies of certain information (backup copies of inline member -functions, debugging information, and the internal tables that -implement virtual functions) must be kept in each object file that -includes class definitions. You can use this pragma to avoid such -duplication. When a header file containing `\|\c -.B #pragma interface\c -\&\|' is included in a compilation, this auxiliary information -will not be generated (unless the main input source file itself uses -`\|\c -.B #pragma implementation\c -\&\|'). Instead, the object files will contain references to be -resolved at link time. -.TP -.B #pragma implementation -.TP -\fB#pragma implementation "\fP\fIobjects\fP\fB.h"\fP -(C++ only.) -Use this pragma in a main input file, when you want full output from -included header files to be generated (and made globally visible). -The included header file, in turn, should use `\|\c -.B #pragma interface\c -\&\|'. -Backup copies of inline member functions, debugging information, and -the internal tables used to implement virtual functions are all -generated in implementation files. -.Sp -If you use `\|\c -.B #pragma implementation\c -\&\|' with no argument, it applies to an include file with the same -basename as your source file; for example, in `\|\c -.B allclass.cc\c -\&\|', `\|\c -.B #pragma implementation\c -\&\|' by itself is equivalent to `\|\c -.B -#pragma implementation "allclass.h"\c -\&\|'. Use the string argument if you want a single implementation -file to include code from multiple header files. -.Sp -There is no way to split up the contents of a single header file into -multiple implementation files. -.SH FILES -.nf -.ta \w'LIBDIR/g++\-include 'u -file.c C source file -file.h C header (preprocessor) file -file.i preprocessed C source file -file.C C++ source file -file.cc C++ source file -file.cxx C++ source file -file.m Objective-C source file -file.s assembly language file -file.o object file -a.out link edited output -\fITMPDIR\fR/cc\(** temporary files -\fILIBDIR\fR/cpp preprocessor -\fILIBDIR\fR/cc1 compiler for C -\fILIBDIR\fR/cc1plus compiler for C++ -\fILIBDIR\fR/collect linker front end needed on some machines -\fILIBDIR\fR/libgcc.a GCC subroutine library -/lib/crt[01n].o start-up routine -\fILIBDIR\fR/ccrt0 additional start-up routine for C++ -/lib/libc.a standard C library, see -.IR intro (3) -/usr/include standard directory for \fB#include\fP files -\fILIBDIR\fR/include standard gcc directory for \fB#include\fP files -\fILIBDIR\fR/g++\-include additional g++ directory for \fB#include\fP -.Sp -.fi -.I LIBDIR -is usually -.B /usr/local/lib/\c -.IR machine / version . -.br -.I TMPDIR -comes from the environment variable -.B TMPDIR -(default -.B /usr/tmp -if available, else -.B /tmp\c -\&). -.SH "SEE ALSO" -cpp(1), as(1), ld(1), gdb(1), adb(1), dbx(1), sdb(1). -.br -.RB "`\|" gcc "\|', `\|" cpp \|', -.RB "`\|" as "\|', `\|" ld \|', -and -.RB `\| gdb \|' -entries in -.B info\c -\&. -.br -.I -Using and Porting GNU CC (for version 2.0)\c -, Richard M. Stallman; -.I -The C Preprocessor\c -, Richard M. Stallman; -.I -Debugging with GDB: the GNU Source-Level Debugger\c -, Richard M. Stallman and Roland H. Pesch; -.I -Using as: the GNU Assembler\c -, Dean Elsner, Jay Fenlason & friends; -.I -ld: the GNU linker\c -, Steve Chamberlain and Roland Pesch. -.SH BUGS -For instructions on reporting bugs, see the GCC manual. -.SH COPYING -Copyright -.if t \(co -1991, 1992, 1993 Free Software Foundation, Inc. -.PP -Permission is granted to make and distribute verbatim copies of -this manual provided the copyright notice and this permission notice -are preserved on all copies. -.PP -Permission is granted to copy and distribute modified versions of this -manual under the conditions for verbatim copying, provided that the -entire resulting derived work is distributed under the terms of a -permission notice identical to this one. -.PP -Permission is granted to copy and distribute translations of this -manual into another language, under the above conditions for modified -versions, except that this permission notice may be included in -translations approved by the Free Software Foundation instead of in -the original English. -.SH AUTHORS -See the GNU CC Manual for the contributors to GNU CC. |