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Diffstat (limited to 'include/llvm/MC/MCSectionELF.h')
| -rw-r--r-- | include/llvm/MC/MCSectionELF.h | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/include/llvm/MC/MCSectionELF.h b/include/llvm/MC/MCSectionELF.h new file mode 100644 index 000000000000..57fa903f717a --- /dev/null +++ b/include/llvm/MC/MCSectionELF.h @@ -0,0 +1,191 @@ +//===- MCSectionELF.h - ELF Machine Code Sections ---------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file declares the MCSectionELF class. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_MC_MCSECTIONELF_H +#define LLVM_MC_MCSECTIONELF_H + +#include "llvm/MC/MCSection.h" + +namespace llvm { + +/// MCSectionELF - This represents a section on linux, lots of unix variants +/// and some bare metal systems. +class MCSectionELF : public MCSection { + std::string SectionName; + + /// Type - This is the sh_type field of a section, drawn from the enums below. + unsigned Type; + + /// Flags - This is the sh_flags field of a section, drawn from the enums. + /// below. + unsigned Flags; + + /// IsExplicit - Indicates that this section comes from globals with an + /// explicit section specfied. + bool IsExplicit; + +protected: + MCSectionELF(const StringRef &Section, unsigned type, unsigned flags, + SectionKind K, bool isExplicit) + : MCSection(K), SectionName(Section.str()), Type(type), Flags(flags), + IsExplicit(isExplicit) {} +public: + + static MCSectionELF *Create(const StringRef &Section, unsigned Type, + unsigned Flags, SectionKind K, bool isExplicit, + MCContext &Ctx); + + /// ShouldOmitSectionDirective - Decides whether a '.section' directive + /// should be printed before the section name + bool ShouldOmitSectionDirective(const char *Name, + const MCAsmInfo &MAI) const; + + /// ShouldPrintSectionType - Only prints the section type if supported + bool ShouldPrintSectionType(unsigned Ty) const; + + /// HasCommonSymbols - True if this section holds common symbols, this is + /// indicated on the ELF object file by a symbol with SHN_COMMON section + /// header index. + bool HasCommonSymbols() const; + + /// These are the section type and flags fields. An ELF section can have + /// only one Type, but can have more than one of the flags specified. + /// + /// Valid section types. + enum { + // This value marks the section header as inactive. + SHT_NULL = 0x00U, + + // Holds information defined by the program, with custom format and meaning. + SHT_PROGBITS = 0x01U, + + // This section holds a symbol table. + SHT_SYMTAB = 0x02U, + + // The section holds a string table. + SHT_STRTAB = 0x03U, + + // The section holds relocation entries with explicit addends. + SHT_RELA = 0x04U, + + // The section holds a symbol hash table. + SHT_HASH = 0x05U, + + // Information for dynamic linking. + SHT_DYNAMIC = 0x06U, + + // The section holds information that marks the file in some way. + SHT_NOTE = 0x07U, + + // A section of this type occupies no space in the file. + SHT_NOBITS = 0x08U, + + // The section holds relocation entries without explicit addends. + SHT_REL = 0x09U, + + // This section type is reserved but has unspecified semantics. + SHT_SHLIB = 0x0AU, + + // This section holds a symbol table. + SHT_DYNSYM = 0x0BU, + + // This section contains an array of pointers to initialization functions. + SHT_INIT_ARRAY = 0x0EU, + + // This section contains an array of pointers to termination functions. + SHT_FINI_ARRAY = 0x0FU, + + // This section contains an array of pointers to functions that are invoked + // before all other initialization functions. + SHT_PREINIT_ARRAY = 0x10U, + + // A section group is a set of sections that are related and that must be + // treated specially by the linker. + SHT_GROUP = 0x11U, + + // This section is associated with a section of type SHT_SYMTAB, when the + // referenced symbol table contain the escape value SHN_XINDEX + SHT_SYMTAB_SHNDX = 0x12U, + + LAST_KNOWN_SECTION_TYPE = SHT_SYMTAB_SHNDX + }; + + /// Valid section flags. + enum { + // The section contains data that should be writable. + SHF_WRITE = 0x1U, + + // The section occupies memory during execution. + SHF_ALLOC = 0x2U, + + // The section contains executable machine instructions. + SHF_EXECINSTR = 0x4U, + + // The data in the section may be merged to eliminate duplication. + SHF_MERGE = 0x10U, + + // Elements in the section consist of null-terminated character strings. + SHF_STRINGS = 0x20U, + + // A field in this section holds a section header table index. + SHF_INFO_LINK = 0x40U, + + // Adds special ordering requirements for link editors. + SHF_LINK_ORDER = 0x80U, + + // This section requires special OS-specific processing to avoid incorrect + // behavior. + SHF_OS_NONCONFORMING = 0x100U, + + // This section is a member of a section group. + SHF_GROUP = 0x200U, + + // This section holds Thread-Local Storage. + SHF_TLS = 0x400U, + + /// FIRST_TARGET_DEP_FLAG - This is the first flag that subclasses are + /// allowed to specify. + FIRST_TARGET_DEP_FLAG = 0x800U, + + /// TARGET_INDEP_SHF - This is the bitmask for all the target independent + /// section flags. Targets can define their own target flags above these. + /// If they do that, they should implement their own MCSectionELF subclasses + /// and implement the virtual method hooks below to handle printing needs. + TARGET_INDEP_SHF = FIRST_TARGET_DEP_FLAG-1U + }; + + StringRef getSectionName() const { + return StringRef(SectionName); + } + + unsigned getType() const { return Type; } + unsigned getFlags() const { return Flags; } + + virtual void PrintSwitchToSection(const MCAsmInfo &MAI, + raw_ostream &OS) const; + + + /// PrintTargetSpecificSectionFlags - Targets that define their own + /// MCSectionELF subclasses with target specific section flags should + /// implement this method if they end up adding letters to the attributes + /// list. + virtual void PrintTargetSpecificSectionFlags(const MCAsmInfo &MAI, + raw_ostream &OS) const { + } + + +}; + +} // end namespace llvm + +#endif |