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Diffstat (limited to 'lib/Lex/PPMacroExpansion.cpp')
| -rw-r--r-- | lib/Lex/PPMacroExpansion.cpp | 605 |
1 files changed, 605 insertions, 0 deletions
diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp new file mode 100644 index 0000000..55222c9 --- /dev/null +++ b/lib/Lex/PPMacroExpansion.cpp @@ -0,0 +1,605 @@ +//===--- MacroExpansion.cpp - Top level Macro Expansion -------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements the top level handling of macro expasion for the +// preprocessor. +// +//===----------------------------------------------------------------------===// + +#include "clang/Lex/Preprocessor.h" +#include "MacroArgs.h" +#include "clang/Lex/MacroInfo.h" +#include "clang/Basic/SourceManager.h" +#include "clang/Basic/FileManager.h" +#include "clang/Lex/LexDiagnostic.h" +#include <cstdio> +#include <ctime> +using namespace clang; + +/// setMacroInfo - Specify a macro for this identifier. +/// +void Preprocessor::setMacroInfo(IdentifierInfo *II, MacroInfo *MI) { + if (MI) { + Macros[II] = MI; + II->setHasMacroDefinition(true); + } else if (II->hasMacroDefinition()) { + Macros.erase(II); + II->setHasMacroDefinition(false); + } +} + +/// RegisterBuiltinMacro - Register the specified identifier in the identifier +/// table and mark it as a builtin macro to be expanded. +IdentifierInfo *Preprocessor::RegisterBuiltinMacro(const char *Name) { + // Get the identifier. + IdentifierInfo *Id = getIdentifierInfo(Name); + + // Mark it as being a macro that is builtin. + MacroInfo *MI = AllocateMacroInfo(SourceLocation()); + MI->setIsBuiltinMacro(); + setMacroInfo(Id, MI); + return Id; +} + + +/// RegisterBuiltinMacros - Register builtin macros, such as __LINE__ with the +/// identifier table. +void Preprocessor::RegisterBuiltinMacros() { + Ident__LINE__ = RegisterBuiltinMacro("__LINE__"); + Ident__FILE__ = RegisterBuiltinMacro("__FILE__"); + Ident__DATE__ = RegisterBuiltinMacro("__DATE__"); + Ident__TIME__ = RegisterBuiltinMacro("__TIME__"); + Ident__COUNTER__ = RegisterBuiltinMacro("__COUNTER__"); + Ident_Pragma = RegisterBuiltinMacro("_Pragma"); + + // GCC Extensions. + Ident__BASE_FILE__ = RegisterBuiltinMacro("__BASE_FILE__"); + Ident__INCLUDE_LEVEL__ = RegisterBuiltinMacro("__INCLUDE_LEVEL__"); + Ident__TIMESTAMP__ = RegisterBuiltinMacro("__TIMESTAMP__"); +} + +/// isTrivialSingleTokenExpansion - Return true if MI, which has a single token +/// in its expansion, currently expands to that token literally. +static bool isTrivialSingleTokenExpansion(const MacroInfo *MI, + const IdentifierInfo *MacroIdent, + Preprocessor &PP) { + IdentifierInfo *II = MI->getReplacementToken(0).getIdentifierInfo(); + + // If the token isn't an identifier, it's always literally expanded. + if (II == 0) return true; + + // If the identifier is a macro, and if that macro is enabled, it may be + // expanded so it's not a trivial expansion. + if (II->hasMacroDefinition() && PP.getMacroInfo(II)->isEnabled() && + // Fast expanding "#define X X" is ok, because X would be disabled. + II != MacroIdent) + return false; + + // If this is an object-like macro invocation, it is safe to trivially expand + // it. + if (MI->isObjectLike()) return true; + + // If this is a function-like macro invocation, it's safe to trivially expand + // as long as the identifier is not a macro argument. + for (MacroInfo::arg_iterator I = MI->arg_begin(), E = MI->arg_end(); + I != E; ++I) + if (*I == II) + return false; // Identifier is a macro argument. + + return true; +} + + +/// isNextPPTokenLParen - Determine whether the next preprocessor token to be +/// lexed is a '('. If so, consume the token and return true, if not, this +/// method should have no observable side-effect on the lexed tokens. +bool Preprocessor::isNextPPTokenLParen() { + // Do some quick tests for rejection cases. + unsigned Val; + if (CurLexer) + Val = CurLexer->isNextPPTokenLParen(); + else if (CurPTHLexer) + Val = CurPTHLexer->isNextPPTokenLParen(); + else + Val = CurTokenLexer->isNextTokenLParen(); + + if (Val == 2) { + // We have run off the end. If it's a source file we don't + // examine enclosing ones (C99 5.1.1.2p4). Otherwise walk up the + // macro stack. + if (CurPPLexer) + return false; + for (unsigned i = IncludeMacroStack.size(); i != 0; --i) { + IncludeStackInfo &Entry = IncludeMacroStack[i-1]; + if (Entry.TheLexer) + Val = Entry.TheLexer->isNextPPTokenLParen(); + else if (Entry.ThePTHLexer) + Val = Entry.ThePTHLexer->isNextPPTokenLParen(); + else + Val = Entry.TheTokenLexer->isNextTokenLParen(); + + if (Val != 2) + break; + + // Ran off the end of a source file? + if (Entry.ThePPLexer) + return false; + } + } + + // Okay, if we know that the token is a '(', lex it and return. Otherwise we + // have found something that isn't a '(' or we found the end of the + // translation unit. In either case, return false. + return Val == 1; +} + +/// HandleMacroExpandedIdentifier - If an identifier token is read that is to be +/// expanded as a macro, handle it and return the next token as 'Identifier'. +bool Preprocessor::HandleMacroExpandedIdentifier(Token &Identifier, + MacroInfo *MI) { + if (Callbacks) Callbacks->MacroExpands(Identifier, MI); + + // If this is a macro exapnsion in the "#if !defined(x)" line for the file, + // then the macro could expand to different things in other contexts, we need + // to disable the optimization in this case. + if (CurPPLexer) CurPPLexer->MIOpt.ExpandedMacro(); + + // If this is a builtin macro, like __LINE__ or _Pragma, handle it specially. + if (MI->isBuiltinMacro()) { + ExpandBuiltinMacro(Identifier); + return false; + } + + /// Args - If this is a function-like macro expansion, this contains, + /// for each macro argument, the list of tokens that were provided to the + /// invocation. + MacroArgs *Args = 0; + + // Remember where the end of the instantiation occurred. For an object-like + // macro, this is the identifier. For a function-like macro, this is the ')'. + SourceLocation InstantiationEnd = Identifier.getLocation(); + + // If this is a function-like macro, read the arguments. + if (MI->isFunctionLike()) { + // C99 6.10.3p10: If the preprocessing token immediately after the the macro + // name isn't a '(', this macro should not be expanded. + if (!isNextPPTokenLParen()) + return true; + + // Remember that we are now parsing the arguments to a macro invocation. + // Preprocessor directives used inside macro arguments are not portable, and + // this enables the warning. + InMacroArgs = true; + Args = ReadFunctionLikeMacroArgs(Identifier, MI, InstantiationEnd); + + // Finished parsing args. + InMacroArgs = false; + + // If there was an error parsing the arguments, bail out. + if (Args == 0) return false; + + ++NumFnMacroExpanded; + } else { + ++NumMacroExpanded; + } + + // Notice that this macro has been used. + MI->setIsUsed(true); + + // If we started lexing a macro, enter the macro expansion body. + + // If this macro expands to no tokens, don't bother to push it onto the + // expansion stack, only to take it right back off. + if (MI->getNumTokens() == 0) { + // No need for arg info. + if (Args) Args->destroy(); + + // Ignore this macro use, just return the next token in the current + // buffer. + bool HadLeadingSpace = Identifier.hasLeadingSpace(); + bool IsAtStartOfLine = Identifier.isAtStartOfLine(); + + Lex(Identifier); + + // If the identifier isn't on some OTHER line, inherit the leading + // whitespace/first-on-a-line property of this token. This handles + // stuff like "! XX," -> "! ," and " XX," -> " ,", when XX is + // empty. + if (!Identifier.isAtStartOfLine()) { + if (IsAtStartOfLine) Identifier.setFlag(Token::StartOfLine); + if (HadLeadingSpace) Identifier.setFlag(Token::LeadingSpace); + } + ++NumFastMacroExpanded; + return false; + + } else if (MI->getNumTokens() == 1 && + isTrivialSingleTokenExpansion(MI, Identifier.getIdentifierInfo(), + *this)) { + // Otherwise, if this macro expands into a single trivially-expanded + // token: expand it now. This handles common cases like + // "#define VAL 42". + + // No need for arg info. + if (Args) Args->destroy(); + + // Propagate the isAtStartOfLine/hasLeadingSpace markers of the macro + // identifier to the expanded token. + bool isAtStartOfLine = Identifier.isAtStartOfLine(); + bool hasLeadingSpace = Identifier.hasLeadingSpace(); + + // Remember where the token is instantiated. + SourceLocation InstantiateLoc = Identifier.getLocation(); + + // Replace the result token. + Identifier = MI->getReplacementToken(0); + + // Restore the StartOfLine/LeadingSpace markers. + Identifier.setFlagValue(Token::StartOfLine , isAtStartOfLine); + Identifier.setFlagValue(Token::LeadingSpace, hasLeadingSpace); + + // Update the tokens location to include both its instantiation and physical + // locations. + SourceLocation Loc = + SourceMgr.createInstantiationLoc(Identifier.getLocation(), InstantiateLoc, + InstantiationEnd,Identifier.getLength()); + Identifier.setLocation(Loc); + + // If this is #define X X, we must mark the result as unexpandible. + if (IdentifierInfo *NewII = Identifier.getIdentifierInfo()) + if (getMacroInfo(NewII) == MI) + Identifier.setFlag(Token::DisableExpand); + + // Since this is not an identifier token, it can't be macro expanded, so + // we're done. + ++NumFastMacroExpanded; + return false; + } + + // Start expanding the macro. + EnterMacro(Identifier, InstantiationEnd, Args); + + // Now that the macro is at the top of the include stack, ask the + // preprocessor to read the next token from it. + Lex(Identifier); + return false; +} + +/// ReadFunctionLikeMacroArgs - After reading "MACRO" and knowing that the next +/// token is the '(' of the macro, this method is invoked to read all of the +/// actual arguments specified for the macro invocation. This returns null on +/// error. +MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName, + MacroInfo *MI, + SourceLocation &MacroEnd) { + // The number of fixed arguments to parse. + unsigned NumFixedArgsLeft = MI->getNumArgs(); + bool isVariadic = MI->isVariadic(); + + // Outer loop, while there are more arguments, keep reading them. + Token Tok; + + // Read arguments as unexpanded tokens. This avoids issues, e.g., where + // an argument value in a macro could expand to ',' or '(' or ')'. + LexUnexpandedToken(Tok); + assert(Tok.is(tok::l_paren) && "Error computing l-paren-ness?"); + + // ArgTokens - Build up a list of tokens that make up each argument. Each + // argument is separated by an EOF token. Use a SmallVector so we can avoid + // heap allocations in the common case. + llvm::SmallVector<Token, 64> ArgTokens; + + unsigned NumActuals = 0; + while (Tok.isNot(tok::r_paren)) { + assert((Tok.is(tok::l_paren) || Tok.is(tok::comma)) && + "only expect argument separators here"); + + unsigned ArgTokenStart = ArgTokens.size(); + SourceLocation ArgStartLoc = Tok.getLocation(); + + // C99 6.10.3p11: Keep track of the number of l_parens we have seen. Note + // that we already consumed the first one. + unsigned NumParens = 0; + + while (1) { + // Read arguments as unexpanded tokens. This avoids issues, e.g., where + // an argument value in a macro could expand to ',' or '(' or ')'. + LexUnexpandedToken(Tok); + + if (Tok.is(tok::eof) || Tok.is(tok::eom)) { // "#if f(<eof>" & "#if f(\n" + Diag(MacroName, diag::err_unterm_macro_invoc); + // Do not lose the EOF/EOM. Return it to the client. + MacroName = Tok; + return 0; + } else if (Tok.is(tok::r_paren)) { + // If we found the ) token, the macro arg list is done. + if (NumParens-- == 0) { + MacroEnd = Tok.getLocation(); + break; + } + } else if (Tok.is(tok::l_paren)) { + ++NumParens; + } else if (Tok.is(tok::comma) && NumParens == 0) { + // Comma ends this argument if there are more fixed arguments expected. + // However, if this is a variadic macro, and this is part of the + // variadic part, then the comma is just an argument token. + if (!isVariadic) break; + if (NumFixedArgsLeft > 1) + break; + } else if (Tok.is(tok::comment) && !KeepMacroComments) { + // If this is a comment token in the argument list and we're just in + // -C mode (not -CC mode), discard the comment. + continue; + } else if (Tok.getIdentifierInfo() != 0) { + // Reading macro arguments can cause macros that we are currently + // expanding from to be popped off the expansion stack. Doing so causes + // them to be reenabled for expansion. Here we record whether any + // identifiers we lex as macro arguments correspond to disabled macros. + // If so, we mark the token as noexpand. This is a subtle aspect of + // C99 6.10.3.4p2. + if (MacroInfo *MI = getMacroInfo(Tok.getIdentifierInfo())) + if (!MI->isEnabled()) + Tok.setFlag(Token::DisableExpand); + } + ArgTokens.push_back(Tok); + } + + // If this was an empty argument list foo(), don't add this as an empty + // argument. + if (ArgTokens.empty() && Tok.getKind() == tok::r_paren) + break; + + // If this is not a variadic macro, and too many args were specified, emit + // an error. + if (!isVariadic && NumFixedArgsLeft == 0) { + if (ArgTokens.size() != ArgTokenStart) + ArgStartLoc = ArgTokens[ArgTokenStart].getLocation(); + + // Emit the diagnostic at the macro name in case there is a missing ). + // Emitting it at the , could be far away from the macro name. + Diag(ArgStartLoc, diag::err_too_many_args_in_macro_invoc); + return 0; + } + + // Empty arguments are standard in C99 and supported as an extension in + // other modes. + if (ArgTokens.size() == ArgTokenStart && !Features.C99) + Diag(Tok, diag::ext_empty_fnmacro_arg); + + // Add a marker EOF token to the end of the token list for this argument. + Token EOFTok; + EOFTok.startToken(); + EOFTok.setKind(tok::eof); + EOFTok.setLocation(Tok.getLocation()); + EOFTok.setLength(0); + ArgTokens.push_back(EOFTok); + ++NumActuals; + assert(NumFixedArgsLeft != 0 && "Too many arguments parsed"); + --NumFixedArgsLeft; + } + + // Okay, we either found the r_paren. Check to see if we parsed too few + // arguments. + unsigned MinArgsExpected = MI->getNumArgs(); + + // See MacroArgs instance var for description of this. + bool isVarargsElided = false; + + if (NumActuals < MinArgsExpected) { + // There are several cases where too few arguments is ok, handle them now. + if (NumActuals == 0 && MinArgsExpected == 1) { + // #define A(X) or #define A(...) ---> A() + + // If there is exactly one argument, and that argument is missing, + // then we have an empty "()" argument empty list. This is fine, even if + // the macro expects one argument (the argument is just empty). + isVarargsElided = MI->isVariadic(); + } else if (MI->isVariadic() && + (NumActuals+1 == MinArgsExpected || // A(x, ...) -> A(X) + (NumActuals == 0 && MinArgsExpected == 2))) {// A(x,...) -> A() + // Varargs where the named vararg parameter is missing: ok as extension. + // #define A(x, ...) + // A("blah") + Diag(Tok, diag::ext_missing_varargs_arg); + + // Remember this occurred, allowing us to elide the comma when used for + // cases like: + // #define A(x, foo...) blah(a, ## foo) + // #define B(x, ...) blah(a, ## __VA_ARGS__) + // #define C(...) blah(a, ## __VA_ARGS__) + // A(x) B(x) C() + isVarargsElided = true; + } else { + // Otherwise, emit the error. + Diag(Tok, diag::err_too_few_args_in_macro_invoc); + return 0; + } + + // Add a marker EOF token to the end of the token list for this argument. + SourceLocation EndLoc = Tok.getLocation(); + Tok.startToken(); + Tok.setKind(tok::eof); + Tok.setLocation(EndLoc); + Tok.setLength(0); + ArgTokens.push_back(Tok); + + // If we expect two arguments, add both as empty. + if (NumActuals == 0 && MinArgsExpected == 2) + ArgTokens.push_back(Tok); + + } else if (NumActuals > MinArgsExpected && !MI->isVariadic()) { + // Emit the diagnostic at the macro name in case there is a missing ). + // Emitting it at the , could be far away from the macro name. + Diag(MacroName, diag::err_too_many_args_in_macro_invoc); + return 0; + } + + return MacroArgs::create(MI, ArgTokens.data(), ArgTokens.size(), + isVarargsElided); +} + +/// ComputeDATE_TIME - Compute the current time, enter it into the specified +/// scratch buffer, then return DATELoc/TIMELoc locations with the position of +/// the identifier tokens inserted. +static void ComputeDATE_TIME(SourceLocation &DATELoc, SourceLocation &TIMELoc, + Preprocessor &PP) { + time_t TT = time(0); + struct tm *TM = localtime(&TT); + + static const char * const Months[] = { + "Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec" + }; + + char TmpBuffer[100]; + sprintf(TmpBuffer, "\"%s %2d %4d\"", Months[TM->tm_mon], TM->tm_mday, + TM->tm_year+1900); + + Token TmpTok; + TmpTok.startToken(); + PP.CreateString(TmpBuffer, strlen(TmpBuffer), TmpTok); + DATELoc = TmpTok.getLocation(); + + sprintf(TmpBuffer, "\"%02d:%02d:%02d\"", TM->tm_hour, TM->tm_min, TM->tm_sec); + PP.CreateString(TmpBuffer, strlen(TmpBuffer), TmpTok); + TIMELoc = TmpTok.getLocation(); +} + +/// ExpandBuiltinMacro - If an identifier token is read that is to be expanded +/// as a builtin macro, handle it and return the next token as 'Tok'. +void Preprocessor::ExpandBuiltinMacro(Token &Tok) { + // Figure out which token this is. + IdentifierInfo *II = Tok.getIdentifierInfo(); + assert(II && "Can't be a macro without id info!"); + + // If this is an _Pragma directive, expand it, invoke the pragma handler, then + // lex the token after it. + if (II == Ident_Pragma) + return Handle_Pragma(Tok); + + ++NumBuiltinMacroExpanded; + + char TmpBuffer[100]; + + // Set up the return result. + Tok.setIdentifierInfo(0); + Tok.clearFlag(Token::NeedsCleaning); + + if (II == Ident__LINE__) { + // C99 6.10.8: "__LINE__: The presumed line number (within the current + // source file) of the current source line (an integer constant)". This can + // be affected by #line. + SourceLocation Loc = Tok.getLocation(); + + // Advance to the location of the first _, this might not be the first byte + // of the token if it starts with an escaped newline. + Loc = AdvanceToTokenCharacter(Loc, 0); + + // One wrinkle here is that GCC expands __LINE__ to location of the *end* of + // a macro instantiation. This doesn't matter for object-like macros, but + // can matter for a function-like macro that expands to contain __LINE__. + // Skip down through instantiation points until we find a file loc for the + // end of the instantiation history. + Loc = SourceMgr.getInstantiationRange(Loc).second; + PresumedLoc PLoc = SourceMgr.getPresumedLoc(Loc); + + // __LINE__ expands to a simple numeric value. + sprintf(TmpBuffer, "%u", PLoc.getLine()); + Tok.setKind(tok::numeric_constant); + CreateString(TmpBuffer, strlen(TmpBuffer), Tok, Tok.getLocation()); + } else if (II == Ident__FILE__ || II == Ident__BASE_FILE__) { + // C99 6.10.8: "__FILE__: The presumed name of the current source file (a + // character string literal)". This can be affected by #line. + PresumedLoc PLoc = SourceMgr.getPresumedLoc(Tok.getLocation()); + + // __BASE_FILE__ is a GNU extension that returns the top of the presumed + // #include stack instead of the current file. + if (II == Ident__BASE_FILE__) { + Diag(Tok, diag::ext_pp_base_file); + SourceLocation NextLoc = PLoc.getIncludeLoc(); + while (NextLoc.isValid()) { + PLoc = SourceMgr.getPresumedLoc(NextLoc); + NextLoc = PLoc.getIncludeLoc(); + } + } + + // Escape this filename. Turn '\' -> '\\' '"' -> '\"' + std::string FN = PLoc.getFilename(); + FN = '"' + Lexer::Stringify(FN) + '"'; + Tok.setKind(tok::string_literal); + CreateString(&FN[0], FN.size(), Tok, Tok.getLocation()); + } else if (II == Ident__DATE__) { + if (!DATELoc.isValid()) + ComputeDATE_TIME(DATELoc, TIMELoc, *this); + Tok.setKind(tok::string_literal); + Tok.setLength(strlen("\"Mmm dd yyyy\"")); + Tok.setLocation(SourceMgr.createInstantiationLoc(DATELoc, Tok.getLocation(), + Tok.getLocation(), + Tok.getLength())); + } else if (II == Ident__TIME__) { + if (!TIMELoc.isValid()) + ComputeDATE_TIME(DATELoc, TIMELoc, *this); + Tok.setKind(tok::string_literal); + Tok.setLength(strlen("\"hh:mm:ss\"")); + Tok.setLocation(SourceMgr.createInstantiationLoc(TIMELoc, Tok.getLocation(), + Tok.getLocation(), + Tok.getLength())); + } else if (II == Ident__INCLUDE_LEVEL__) { + Diag(Tok, diag::ext_pp_include_level); + + // Compute the presumed include depth of this token. This can be affected + // by GNU line markers. + unsigned Depth = 0; + + PresumedLoc PLoc = SourceMgr.getPresumedLoc(Tok.getLocation()); + PLoc = SourceMgr.getPresumedLoc(PLoc.getIncludeLoc()); + for (; PLoc.isValid(); ++Depth) + PLoc = SourceMgr.getPresumedLoc(PLoc.getIncludeLoc()); + + // __INCLUDE_LEVEL__ expands to a simple numeric value. + sprintf(TmpBuffer, "%u", Depth); + Tok.setKind(tok::numeric_constant); + CreateString(TmpBuffer, strlen(TmpBuffer), Tok, Tok.getLocation()); + } else if (II == Ident__TIMESTAMP__) { + // MSVC, ICC, GCC, VisualAge C++ extension. The generated string should be + // of the form "Ddd Mmm dd hh::mm::ss yyyy", which is returned by asctime. + Diag(Tok, diag::ext_pp_timestamp); + + // Get the file that we are lexing out of. If we're currently lexing from + // a macro, dig into the include stack. + const FileEntry *CurFile = 0; + PreprocessorLexer *TheLexer = getCurrentFileLexer(); + + if (TheLexer) + CurFile = SourceMgr.getFileEntryForID(TheLexer->getFileID()); + + // If this file is older than the file it depends on, emit a diagnostic. + const char *Result; + if (CurFile) { + time_t TT = CurFile->getModificationTime(); + struct tm *TM = localtime(&TT); + Result = asctime(TM); + } else { + Result = "??? ??? ?? ??:??:?? ????\n"; + } + TmpBuffer[0] = '"'; + strcpy(TmpBuffer+1, Result); + unsigned Len = strlen(TmpBuffer); + TmpBuffer[Len] = '"'; // Replace the newline with a quote. + Tok.setKind(tok::string_literal); + CreateString(TmpBuffer, Len+1, Tok, Tok.getLocation()); + } else if (II == Ident__COUNTER__) { + Diag(Tok, diag::ext_pp_counter); + + // __COUNTER__ expands to a simple numeric value. + sprintf(TmpBuffer, "%u", CounterValue++); + Tok.setKind(tok::numeric_constant); + CreateString(TmpBuffer, strlen(TmpBuffer), Tok, Tok.getLocation()); + } else { + assert(0 && "Unknown identifier!"); + } +} |
