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Diffstat (limited to 'llvm/lib/TableGen/TGLexer.cpp')
| -rw-r--r-- | llvm/lib/TableGen/TGLexer.cpp | 1021 |
1 files changed, 1021 insertions, 0 deletions
diff --git a/llvm/lib/TableGen/TGLexer.cpp b/llvm/lib/TableGen/TGLexer.cpp new file mode 100644 index 000000000000..da2286e41fe5 --- /dev/null +++ b/llvm/lib/TableGen/TGLexer.cpp @@ -0,0 +1,1021 @@ +//===- TGLexer.cpp - Lexer for TableGen -----------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// Implement the Lexer for TableGen. +// +//===----------------------------------------------------------------------===// + +#include "TGLexer.h" +#include "llvm/ADT/StringSwitch.h" +#include "llvm/ADT/Twine.h" +#include "llvm/Config/config.h" // for strtoull()/strtoll() define +#include "llvm/Support/Compiler.h" +#include "llvm/Support/MemoryBuffer.h" +#include "llvm/Support/SourceMgr.h" +#include "llvm/TableGen/Error.h" +#include <algorithm> +#include <cctype> +#include <cerrno> +#include <cstdint> +#include <cstdio> +#include <cstdlib> +#include <cstring> + +using namespace llvm; + +namespace { +// A list of supported preprocessing directives with their +// internal token kinds and names. +struct { + tgtok::TokKind Kind; + const char *Word; +} PreprocessorDirs[] = { + { tgtok::Ifdef, "ifdef" }, + { tgtok::Ifndef, "ifndef" }, + { tgtok::Else, "else" }, + { tgtok::Endif, "endif" }, + { tgtok::Define, "define" } +}; +} // end anonymous namespace + +TGLexer::TGLexer(SourceMgr &SM, ArrayRef<std::string> Macros) : SrcMgr(SM) { + CurBuffer = SrcMgr.getMainFileID(); + CurBuf = SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer(); + CurPtr = CurBuf.begin(); + TokStart = nullptr; + + // Pretend that we enter the "top-level" include file. + PrepIncludeStack.push_back( + std::make_unique<std::vector<PreprocessorControlDesc>>()); + + // Put all macros defined in the command line into the DefinedMacros set. + std::for_each(Macros.begin(), Macros.end(), + [this](const std::string &MacroName) { + DefinedMacros.insert(MacroName); + }); +} + +SMLoc TGLexer::getLoc() const { + return SMLoc::getFromPointer(TokStart); +} + +/// ReturnError - Set the error to the specified string at the specified +/// location. This is defined to always return tgtok::Error. +tgtok::TokKind TGLexer::ReturnError(SMLoc Loc, const Twine &Msg) { + PrintError(Loc, Msg); + return tgtok::Error; +} + +tgtok::TokKind TGLexer::ReturnError(const char *Loc, const Twine &Msg) { + return ReturnError(SMLoc::getFromPointer(Loc), Msg); +} + +bool TGLexer::processEOF() { + SMLoc ParentIncludeLoc = SrcMgr.getParentIncludeLoc(CurBuffer); + if (ParentIncludeLoc != SMLoc()) { + // If prepExitInclude() detects a problem with the preprocessing + // control stack, it will return false. Pretend that we reached + // the final EOF and stop lexing more tokens by returning false + // to LexToken(). + if (!prepExitInclude(false)) + return false; + + CurBuffer = SrcMgr.FindBufferContainingLoc(ParentIncludeLoc); + CurBuf = SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer(); + CurPtr = ParentIncludeLoc.getPointer(); + // Make sure TokStart points into the parent file's buffer. + // LexToken() assigns to it before calling getNextChar(), + // so it is pointing into the included file now. + TokStart = CurPtr; + return true; + } + + // Pretend that we exit the "top-level" include file. + // Note that in case of an error (e.g. control stack imbalance) + // the routine will issue a fatal error. + prepExitInclude(true); + return false; +} + +int TGLexer::getNextChar() { + char CurChar = *CurPtr++; + switch (CurChar) { + default: + return (unsigned char)CurChar; + case 0: { + // A nul character in the stream is either the end of the current buffer or + // a random nul in the file. Disambiguate that here. + if (CurPtr-1 != CurBuf.end()) + return 0; // Just whitespace. + + // Otherwise, return end of file. + --CurPtr; // Another call to lex will return EOF again. + return EOF; + } + case '\n': + case '\r': + // Handle the newline character by ignoring it and incrementing the line + // count. However, be careful about 'dos style' files with \n\r in them. + // Only treat a \n\r or \r\n as a single line. + if ((*CurPtr == '\n' || (*CurPtr == '\r')) && + *CurPtr != CurChar) + ++CurPtr; // Eat the two char newline sequence. + return '\n'; + } +} + +int TGLexer::peekNextChar(int Index) const { + return *(CurPtr + Index); +} + +tgtok::TokKind TGLexer::LexToken(bool FileOrLineStart) { + TokStart = CurPtr; + // This always consumes at least one character. + int CurChar = getNextChar(); + + switch (CurChar) { + default: + // Handle letters: [a-zA-Z_] + if (isalpha(CurChar) || CurChar == '_') + return LexIdentifier(); + + // Unknown character, emit an error. + return ReturnError(TokStart, "Unexpected character"); + case EOF: + // Lex next token, if we just left an include file. + // Note that leaving an include file means that the next + // symbol is located at the end of 'include "..."' + // construct, so LexToken() is called with default + // false parameter. + if (processEOF()) + return LexToken(); + + // Return EOF denoting the end of lexing. + return tgtok::Eof; + + case ':': return tgtok::colon; + case ';': return tgtok::semi; + case '.': return tgtok::period; + case ',': return tgtok::comma; + case '<': return tgtok::less; + case '>': return tgtok::greater; + case ']': return tgtok::r_square; + case '{': return tgtok::l_brace; + case '}': return tgtok::r_brace; + case '(': return tgtok::l_paren; + case ')': return tgtok::r_paren; + case '=': return tgtok::equal; + case '?': return tgtok::question; + case '#': + if (FileOrLineStart) { + tgtok::TokKind Kind = prepIsDirective(); + if (Kind != tgtok::Error) + return lexPreprocessor(Kind); + } + + return tgtok::paste; + + case '\r': + PrintFatalError("getNextChar() must never return '\r'"); + return tgtok::Error; + + case 0: + case ' ': + case '\t': + // Ignore whitespace. + return LexToken(FileOrLineStart); + case '\n': + // Ignore whitespace, and identify the new line. + return LexToken(true); + case '/': + // If this is the start of a // comment, skip until the end of the line or + // the end of the buffer. + if (*CurPtr == '/') + SkipBCPLComment(); + else if (*CurPtr == '*') { + if (SkipCComment()) + return tgtok::Error; + } else // Otherwise, this is an error. + return ReturnError(TokStart, "Unexpected character"); + return LexToken(FileOrLineStart); + case '-': case '+': + case '0': case '1': case '2': case '3': case '4': case '5': case '6': + case '7': case '8': case '9': { + int NextChar = 0; + if (isdigit(CurChar)) { + // Allow identifiers to start with a number if it is followed by + // an identifier. This can happen with paste operations like + // foo#8i. + int i = 0; + do { + NextChar = peekNextChar(i++); + } while (isdigit(NextChar)); + + if (NextChar == 'x' || NextChar == 'b') { + // If this is [0-9]b[01] or [0-9]x[0-9A-fa-f] this is most + // likely a number. + int NextNextChar = peekNextChar(i); + switch (NextNextChar) { + default: + break; + case '0': case '1': + if (NextChar == 'b') + return LexNumber(); + LLVM_FALLTHROUGH; + case '2': case '3': case '4': case '5': + case '6': case '7': case '8': case '9': + case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': + case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': + if (NextChar == 'x') + return LexNumber(); + break; + } + } + } + + if (isalpha(NextChar) || NextChar == '_') + return LexIdentifier(); + + return LexNumber(); + } + case '"': return LexString(); + case '$': return LexVarName(); + case '[': return LexBracket(); + case '!': return LexExclaim(); + } +} + +/// LexString - Lex "[^"]*" +tgtok::TokKind TGLexer::LexString() { + const char *StrStart = CurPtr; + + CurStrVal = ""; + + while (*CurPtr != '"') { + // If we hit the end of the buffer, report an error. + if (*CurPtr == 0 && CurPtr == CurBuf.end()) + return ReturnError(StrStart, "End of file in string literal"); + + if (*CurPtr == '\n' || *CurPtr == '\r') + return ReturnError(StrStart, "End of line in string literal"); + + if (*CurPtr != '\\') { + CurStrVal += *CurPtr++; + continue; + } + + ++CurPtr; + + switch (*CurPtr) { + case '\\': case '\'': case '"': + // These turn into their literal character. + CurStrVal += *CurPtr++; + break; + case 't': + CurStrVal += '\t'; + ++CurPtr; + break; + case 'n': + CurStrVal += '\n'; + ++CurPtr; + break; + + case '\n': + case '\r': + return ReturnError(CurPtr, "escaped newlines not supported in tblgen"); + + // If we hit the end of the buffer, report an error. + case '\0': + if (CurPtr == CurBuf.end()) + return ReturnError(StrStart, "End of file in string literal"); + LLVM_FALLTHROUGH; + default: + return ReturnError(CurPtr, "invalid escape in string literal"); + } + } + + ++CurPtr; + return tgtok::StrVal; +} + +tgtok::TokKind TGLexer::LexVarName() { + if (!isalpha(CurPtr[0]) && CurPtr[0] != '_') + return ReturnError(TokStart, "Invalid variable name"); + + // Otherwise, we're ok, consume the rest of the characters. + const char *VarNameStart = CurPtr++; + + while (isalpha(*CurPtr) || isdigit(*CurPtr) || *CurPtr == '_') + ++CurPtr; + + CurStrVal.assign(VarNameStart, CurPtr); + return tgtok::VarName; +} + +tgtok::TokKind TGLexer::LexIdentifier() { + // The first letter is [a-zA-Z_]. + const char *IdentStart = TokStart; + + // Match the rest of the identifier regex: [0-9a-zA-Z_]* + while (isalpha(*CurPtr) || isdigit(*CurPtr) || *CurPtr == '_') + ++CurPtr; + + // Check to see if this identifier is a keyword. + StringRef Str(IdentStart, CurPtr-IdentStart); + + if (Str == "include") { + if (LexInclude()) return tgtok::Error; + return Lex(); + } + + tgtok::TokKind Kind = StringSwitch<tgtok::TokKind>(Str) + .Case("int", tgtok::Int) + .Case("bit", tgtok::Bit) + .Case("bits", tgtok::Bits) + .Case("string", tgtok::String) + .Case("list", tgtok::List) + .Case("code", tgtok::Code) + .Case("dag", tgtok::Dag) + .Case("class", tgtok::Class) + .Case("def", tgtok::Def) + .Case("foreach", tgtok::Foreach) + .Case("defm", tgtok::Defm) + .Case("defset", tgtok::Defset) + .Case("multiclass", tgtok::MultiClass) + .Case("field", tgtok::Field) + .Case("let", tgtok::Let) + .Case("in", tgtok::In) + .Default(tgtok::Id); + + if (Kind == tgtok::Id) + CurStrVal.assign(Str.begin(), Str.end()); + return Kind; +} + +/// LexInclude - We just read the "include" token. Get the string token that +/// comes next and enter the include. +bool TGLexer::LexInclude() { + // The token after the include must be a string. + tgtok::TokKind Tok = LexToken(); + if (Tok == tgtok::Error) return true; + if (Tok != tgtok::StrVal) { + PrintError(getLoc(), "Expected filename after include"); + return true; + } + + // Get the string. + std::string Filename = CurStrVal; + std::string IncludedFile; + + CurBuffer = SrcMgr.AddIncludeFile(Filename, SMLoc::getFromPointer(CurPtr), + IncludedFile); + if (!CurBuffer) { + PrintError(getLoc(), "Could not find include file '" + Filename + "'"); + return true; + } + + DependenciesMapTy::const_iterator Found = Dependencies.find(IncludedFile); + if (Found != Dependencies.end()) { + PrintError(getLoc(), + "File '" + IncludedFile + "' has already been included."); + SrcMgr.PrintMessage(Found->second, SourceMgr::DK_Note, + "previously included here"); + return true; + } + Dependencies.insert(std::make_pair(IncludedFile, getLoc())); + // Save the line number and lex buffer of the includer. + CurBuf = SrcMgr.getMemoryBuffer(CurBuffer)->getBuffer(); + CurPtr = CurBuf.begin(); + + PrepIncludeStack.push_back( + std::make_unique<std::vector<PreprocessorControlDesc>>()); + return false; +} + +void TGLexer::SkipBCPLComment() { + ++CurPtr; // skip the second slash. + while (true) { + switch (*CurPtr) { + case '\n': + case '\r': + return; // Newline is end of comment. + case 0: + // If this is the end of the buffer, end the comment. + if (CurPtr == CurBuf.end()) + return; + break; + } + // Otherwise, skip the character. + ++CurPtr; + } +} + +/// SkipCComment - This skips C-style /**/ comments. The only difference from C +/// is that we allow nesting. +bool TGLexer::SkipCComment() { + ++CurPtr; // skip the star. + unsigned CommentDepth = 1; + + while (true) { + int CurChar = getNextChar(); + switch (CurChar) { + case EOF: + PrintError(TokStart, "Unterminated comment!"); + return true; + case '*': + // End of the comment? + if (CurPtr[0] != '/') break; + + ++CurPtr; // End the */. + if (--CommentDepth == 0) + return false; + break; + case '/': + // Start of a nested comment? + if (CurPtr[0] != '*') break; + ++CurPtr; + ++CommentDepth; + break; + } + } +} + +/// LexNumber - Lex: +/// [-+]?[0-9]+ +/// 0x[0-9a-fA-F]+ +/// 0b[01]+ +tgtok::TokKind TGLexer::LexNumber() { + if (CurPtr[-1] == '0') { + if (CurPtr[0] == 'x') { + ++CurPtr; + const char *NumStart = CurPtr; + while (isxdigit(CurPtr[0])) + ++CurPtr; + + // Requires at least one hex digit. + if (CurPtr == NumStart) + return ReturnError(TokStart, "Invalid hexadecimal number"); + + errno = 0; + CurIntVal = strtoll(NumStart, nullptr, 16); + if (errno == EINVAL) + return ReturnError(TokStart, "Invalid hexadecimal number"); + if (errno == ERANGE) { + errno = 0; + CurIntVal = (int64_t)strtoull(NumStart, nullptr, 16); + if (errno == EINVAL) + return ReturnError(TokStart, "Invalid hexadecimal number"); + if (errno == ERANGE) + return ReturnError(TokStart, "Hexadecimal number out of range"); + } + return tgtok::IntVal; + } else if (CurPtr[0] == 'b') { + ++CurPtr; + const char *NumStart = CurPtr; + while (CurPtr[0] == '0' || CurPtr[0] == '1') + ++CurPtr; + + // Requires at least one binary digit. + if (CurPtr == NumStart) + return ReturnError(CurPtr-2, "Invalid binary number"); + CurIntVal = strtoll(NumStart, nullptr, 2); + return tgtok::BinaryIntVal; + } + } + + // Check for a sign without a digit. + if (!isdigit(CurPtr[0])) { + if (CurPtr[-1] == '-') + return tgtok::minus; + else if (CurPtr[-1] == '+') + return tgtok::plus; + } + + while (isdigit(CurPtr[0])) + ++CurPtr; + CurIntVal = strtoll(TokStart, nullptr, 10); + return tgtok::IntVal; +} + +/// LexBracket - We just read '['. If this is a code block, return it, +/// otherwise return the bracket. Match: '[' and '[{ ( [^}]+ | }[^]] )* }]' +tgtok::TokKind TGLexer::LexBracket() { + if (CurPtr[0] != '{') + return tgtok::l_square; + ++CurPtr; + const char *CodeStart = CurPtr; + while (true) { + int Char = getNextChar(); + if (Char == EOF) break; + + if (Char != '}') continue; + + Char = getNextChar(); + if (Char == EOF) break; + if (Char == ']') { + CurStrVal.assign(CodeStart, CurPtr-2); + return tgtok::CodeFragment; + } + } + + return ReturnError(CodeStart-2, "Unterminated Code Block"); +} + +/// LexExclaim - Lex '!' and '![a-zA-Z]+'. +tgtok::TokKind TGLexer::LexExclaim() { + if (!isalpha(*CurPtr)) + return ReturnError(CurPtr - 1, "Invalid \"!operator\""); + + const char *Start = CurPtr++; + while (isalpha(*CurPtr)) + ++CurPtr; + + // Check to see which operator this is. + tgtok::TokKind Kind = + StringSwitch<tgtok::TokKind>(StringRef(Start, CurPtr - Start)) + .Case("eq", tgtok::XEq) + .Case("ne", tgtok::XNe) + .Case("le", tgtok::XLe) + .Case("lt", tgtok::XLt) + .Case("ge", tgtok::XGe) + .Case("gt", tgtok::XGt) + .Case("if", tgtok::XIf) + .Case("cond", tgtok::XCond) + .Case("isa", tgtok::XIsA) + .Case("head", tgtok::XHead) + .Case("tail", tgtok::XTail) + .Case("size", tgtok::XSize) + .Case("con", tgtok::XConcat) + .Case("dag", tgtok::XDag) + .Case("add", tgtok::XADD) + .Case("mul", tgtok::XMUL) + .Case("and", tgtok::XAND) + .Case("or", tgtok::XOR) + .Case("shl", tgtok::XSHL) + .Case("sra", tgtok::XSRA) + .Case("srl", tgtok::XSRL) + .Case("cast", tgtok::XCast) + .Case("empty", tgtok::XEmpty) + .Case("subst", tgtok::XSubst) + .Case("foldl", tgtok::XFoldl) + .Case("foreach", tgtok::XForEach) + .Case("listconcat", tgtok::XListConcat) + .Case("listsplat", tgtok::XListSplat) + .Case("strconcat", tgtok::XStrConcat) + .Default(tgtok::Error); + + return Kind != tgtok::Error ? Kind : ReturnError(Start-1, "Unknown operator"); +} + +bool TGLexer::prepExitInclude(bool IncludeStackMustBeEmpty) { + // Report an error, if preprocessor control stack for the current + // file is not empty. + if (!PrepIncludeStack.back()->empty()) { + prepReportPreprocessorStackError(); + + return false; + } + + // Pop the preprocessing controls from the include stack. + if (PrepIncludeStack.empty()) { + PrintFatalError("Preprocessor include stack is empty"); + } + + PrepIncludeStack.pop_back(); + + if (IncludeStackMustBeEmpty) { + if (!PrepIncludeStack.empty()) + PrintFatalError("Preprocessor include stack is not empty"); + } else { + if (PrepIncludeStack.empty()) + PrintFatalError("Preprocessor include stack is empty"); + } + + return true; +} + +tgtok::TokKind TGLexer::prepIsDirective() const { + for (unsigned ID = 0; ID < llvm::array_lengthof(PreprocessorDirs); ++ID) { + int NextChar = *CurPtr; + bool Match = true; + unsigned I = 0; + for (; I < strlen(PreprocessorDirs[ID].Word); ++I) { + if (NextChar != PreprocessorDirs[ID].Word[I]) { + Match = false; + break; + } + + NextChar = peekNextChar(I + 1); + } + + // Check for whitespace after the directive. If there is no whitespace, + // then we do not recognize it as a preprocessing directive. + if (Match) { + tgtok::TokKind Kind = PreprocessorDirs[ID].Kind; + + // New line and EOF may follow only #else/#endif. It will be reported + // as an error for #ifdef/#define after the call to prepLexMacroName(). + if (NextChar == ' ' || NextChar == '\t' || NextChar == EOF || + NextChar == '\n' || + // It looks like TableGen does not support '\r' as the actual + // carriage return, e.g. getNextChar() treats a single '\r' + // as '\n'. So we do the same here. + NextChar == '\r') + return Kind; + + // Allow comments after some directives, e.g.: + // #else// OR #else/**/ + // #endif// OR #endif/**/ + // + // Note that we do allow comments after #ifdef/#define here, e.g. + // #ifdef/**/ AND #ifdef// + // #define/**/ AND #define// + // + // These cases will be reported as incorrect after calling + // prepLexMacroName(). We could have supported C-style comments + // after #ifdef/#define, but this would complicate the code + // for little benefit. + if (NextChar == '/') { + NextChar = peekNextChar(I + 1); + + if (NextChar == '*' || NextChar == '/') + return Kind; + + // Pretend that we do not recognize the directive. + } + } + } + + return tgtok::Error; +} + +bool TGLexer::prepEatPreprocessorDirective(tgtok::TokKind Kind) { + TokStart = CurPtr; + + for (unsigned ID = 0; ID < llvm::array_lengthof(PreprocessorDirs); ++ID) + if (PreprocessorDirs[ID].Kind == Kind) { + // Advance CurPtr to the end of the preprocessing word. + CurPtr += strlen(PreprocessorDirs[ID].Word); + return true; + } + + PrintFatalError("Unsupported preprocessing token in " + "prepEatPreprocessorDirective()"); + return false; +} + +tgtok::TokKind TGLexer::lexPreprocessor( + tgtok::TokKind Kind, bool ReturnNextLiveToken) { + + // We must be looking at a preprocessing directive. Eat it! + if (!prepEatPreprocessorDirective(Kind)) + PrintFatalError("lexPreprocessor() called for unknown " + "preprocessor directive"); + + if (Kind == tgtok::Ifdef || Kind == tgtok::Ifndef) { + StringRef MacroName = prepLexMacroName(); + StringRef IfTokName = Kind == tgtok::Ifdef ? "#ifdef" : "#ifndef"; + if (MacroName.empty()) + return ReturnError(TokStart, "Expected macro name after " + IfTokName); + + bool MacroIsDefined = DefinedMacros.count(MacroName) != 0; + + // Canonicalize ifndef to ifdef equivalent + if (Kind == tgtok::Ifndef) { + MacroIsDefined = !MacroIsDefined; + Kind = tgtok::Ifdef; + } + + // Regardless of whether we are processing tokens or not, + // we put the #ifdef control on stack. + PrepIncludeStack.back()->push_back( + {Kind, MacroIsDefined, SMLoc::getFromPointer(TokStart)}); + + if (!prepSkipDirectiveEnd()) + return ReturnError(CurPtr, "Only comments are supported after " + + IfTokName + " NAME"); + + // If we were not processing tokens before this #ifdef, + // then just return back to the lines skipping code. + if (!ReturnNextLiveToken) + return Kind; + + // If we were processing tokens before this #ifdef, + // and the macro is defined, then just return the next token. + if (MacroIsDefined) + return LexToken(); + + // We were processing tokens before this #ifdef, and the macro + // is not defined, so we have to start skipping the lines. + // If the skipping is successful, it will return the token following + // either #else or #endif corresponding to this #ifdef. + if (prepSkipRegion(ReturnNextLiveToken)) + return LexToken(); + + return tgtok::Error; + } else if (Kind == tgtok::Else) { + // Check if this #else is correct before calling prepSkipDirectiveEnd(), + // which will move CurPtr away from the beginning of #else. + if (PrepIncludeStack.back()->empty()) + return ReturnError(TokStart, "#else without #ifdef or #ifndef"); + + PreprocessorControlDesc IfdefEntry = PrepIncludeStack.back()->back(); + + if (IfdefEntry.Kind != tgtok::Ifdef) { + PrintError(TokStart, "double #else"); + return ReturnError(IfdefEntry.SrcPos, "Previous #else is here"); + } + + // Replace the corresponding #ifdef's control with its negation + // on the control stack. + PrepIncludeStack.back()->pop_back(); + PrepIncludeStack.back()->push_back( + {Kind, !IfdefEntry.IsDefined, SMLoc::getFromPointer(TokStart)}); + + if (!prepSkipDirectiveEnd()) + return ReturnError(CurPtr, "Only comments are supported after #else"); + + // If we were processing tokens before this #else, + // we have to start skipping lines until the matching #endif. + if (ReturnNextLiveToken) { + if (prepSkipRegion(ReturnNextLiveToken)) + return LexToken(); + + return tgtok::Error; + } + + // Return to the lines skipping code. + return Kind; + } else if (Kind == tgtok::Endif) { + // Check if this #endif is correct before calling prepSkipDirectiveEnd(), + // which will move CurPtr away from the beginning of #endif. + if (PrepIncludeStack.back()->empty()) + return ReturnError(TokStart, "#endif without #ifdef"); + + auto &IfdefOrElseEntry = PrepIncludeStack.back()->back(); + + if (IfdefOrElseEntry.Kind != tgtok::Ifdef && + IfdefOrElseEntry.Kind != tgtok::Else) { + PrintFatalError("Invalid preprocessor control on the stack"); + return tgtok::Error; + } + + if (!prepSkipDirectiveEnd()) + return ReturnError(CurPtr, "Only comments are supported after #endif"); + + PrepIncludeStack.back()->pop_back(); + + // If we were processing tokens before this #endif, then + // we should continue it. + if (ReturnNextLiveToken) { + return LexToken(); + } + + // Return to the lines skipping code. + return Kind; + } else if (Kind == tgtok::Define) { + StringRef MacroName = prepLexMacroName(); + if (MacroName.empty()) + return ReturnError(TokStart, "Expected macro name after #define"); + + if (!DefinedMacros.insert(MacroName).second) + PrintWarning(getLoc(), + "Duplicate definition of macro: " + Twine(MacroName)); + + if (!prepSkipDirectiveEnd()) + return ReturnError(CurPtr, + "Only comments are supported after #define NAME"); + + if (!ReturnNextLiveToken) { + PrintFatalError("#define must be ignored during the lines skipping"); + return tgtok::Error; + } + + return LexToken(); + } + + PrintFatalError("Preprocessing directive is not supported"); + return tgtok::Error; +} + +bool TGLexer::prepSkipRegion(bool MustNeverBeFalse) { + if (!MustNeverBeFalse) + PrintFatalError("Invalid recursion."); + + do { + // Skip all symbols to the line end. + prepSkipToLineEnd(); + + // Find the first non-whitespace symbol in the next line(s). + if (!prepSkipLineBegin()) + return false; + + // If the first non-blank/comment symbol on the line is '#', + // it may be a start of preprocessing directive. + // + // If it is not '#' just go to the next line. + if (*CurPtr == '#') + ++CurPtr; + else + continue; + + tgtok::TokKind Kind = prepIsDirective(); + + // If we did not find a preprocessing directive or it is #define, + // then just skip to the next line. We do not have to do anything + // for #define in the line-skipping mode. + if (Kind == tgtok::Error || Kind == tgtok::Define) + continue; + + tgtok::TokKind ProcessedKind = lexPreprocessor(Kind, false); + + // If lexPreprocessor() encountered an error during lexing this + // preprocessor idiom, then return false to the calling lexPreprocessor(). + // This will force tgtok::Error to be returned to the tokens processing. + if (ProcessedKind == tgtok::Error) + return false; + + if (Kind != ProcessedKind) + PrintFatalError("prepIsDirective() and lexPreprocessor() " + "returned different token kinds"); + + // If this preprocessing directive enables tokens processing, + // then return to the lexPreprocessor() and get to the next token. + // We can move from line-skipping mode to processing tokens only + // due to #else or #endif. + if (prepIsProcessingEnabled()) { + if (Kind != tgtok::Else && Kind != tgtok::Endif) { + PrintFatalError("Tokens processing was enabled by an unexpected " + "preprocessing directive"); + return false; + } + + return true; + } + } while (CurPtr != CurBuf.end()); + + // We have reached the end of the file, but never left the lines-skipping + // mode. This means there is no matching #endif. + prepReportPreprocessorStackError(); + return false; +} + +StringRef TGLexer::prepLexMacroName() { + // Skip whitespaces between the preprocessing directive and the macro name. + while (*CurPtr == ' ' || *CurPtr == '\t') + ++CurPtr; + + TokStart = CurPtr; + // Macro names start with [a-zA-Z_]. + if (*CurPtr != '_' && !isalpha(*CurPtr)) + return ""; + + // Match the rest of the identifier regex: [0-9a-zA-Z_]* + while (isalpha(*CurPtr) || isdigit(*CurPtr) || *CurPtr == '_') + ++CurPtr; + + return StringRef(TokStart, CurPtr - TokStart); +} + +bool TGLexer::prepSkipLineBegin() { + while (CurPtr != CurBuf.end()) { + switch (*CurPtr) { + case ' ': + case '\t': + case '\n': + case '\r': + break; + + case '/': { + int NextChar = peekNextChar(1); + if (NextChar == '*') { + // Skip C-style comment. + // Note that we do not care about skipping the C++-style comments. + // If the line contains "//", it may not contain any processable + // preprocessing directive. Just return CurPtr pointing to + // the first '/' in this case. We also do not care about + // incorrect symbols after the first '/' - we are in lines-skipping + // mode, so incorrect code is allowed to some extent. + + // Set TokStart to the beginning of the comment to enable proper + // diagnostic printing in case of error in SkipCComment(). + TokStart = CurPtr; + + // CurPtr must point to '*' before call to SkipCComment(). + ++CurPtr; + if (SkipCComment()) + return false; + } else { + // CurPtr points to the non-whitespace '/'. + return true; + } + + // We must not increment CurPtr after the comment was lexed. + continue; + } + + default: + return true; + } + + ++CurPtr; + } + + // We have reached the end of the file. Return to the lines skipping + // code, and allow it to handle the EOF as needed. + return true; +} + +bool TGLexer::prepSkipDirectiveEnd() { + while (CurPtr != CurBuf.end()) { + switch (*CurPtr) { + case ' ': + case '\t': + break; + + case '\n': + case '\r': + return true; + + case '/': { + int NextChar = peekNextChar(1); + if (NextChar == '/') { + // Skip C++-style comment. + // We may just return true now, but let's skip to the line/buffer end + // to simplify the method specification. + ++CurPtr; + SkipBCPLComment(); + } else if (NextChar == '*') { + // When we are skipping C-style comment at the end of a preprocessing + // directive, we can skip several lines. If any meaningful TD token + // follows the end of the C-style comment on the same line, it will + // be considered as an invalid usage of TD token. + // For example, we want to forbid usages like this one: + // #define MACRO class Class {} + // But with C-style comments we also disallow the following: + // #define MACRO /* This macro is used + // to ... */ class Class {} + // One can argue that this should be allowed, but it does not seem + // to be worth of the complication. Moreover, this matches + // the C preprocessor behavior. + + // Set TokStart to the beginning of the comment to enable proper + // diagnostic printer in case of error in SkipCComment(). + TokStart = CurPtr; + ++CurPtr; + if (SkipCComment()) + return false; + } else { + TokStart = CurPtr; + PrintError(CurPtr, "Unexpected character"); + return false; + } + + // We must not increment CurPtr after the comment was lexed. + continue; + } + + default: + // Do not allow any non-whitespaces after the directive. + TokStart = CurPtr; + return false; + } + + ++CurPtr; + } + + return true; +} + +void TGLexer::prepSkipToLineEnd() { + while (*CurPtr != '\n' && *CurPtr != '\r' && CurPtr != CurBuf.end()) + ++CurPtr; +} + +bool TGLexer::prepIsProcessingEnabled() { + for (auto I = PrepIncludeStack.back()->rbegin(), + E = PrepIncludeStack.back()->rend(); + I != E; ++I) { + if (!I->IsDefined) + return false; + } + + return true; +} + +void TGLexer::prepReportPreprocessorStackError() { + if (PrepIncludeStack.back()->empty()) + PrintFatalError("prepReportPreprocessorStackError() called with " + "empty control stack"); + + auto &PrepControl = PrepIncludeStack.back()->back(); + PrintError(CurBuf.end(), "Reached EOF without matching #endif"); + PrintError(PrepControl.SrcPos, "The latest preprocessor control is here"); + + TokStart = CurPtr; +} |