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Diffstat (limited to 'clang/lib/Lex/TokenLexer.cpp')
| -rw-r--r-- | clang/lib/Lex/TokenLexer.cpp | 1079 |
1 files changed, 1079 insertions, 0 deletions
diff --git a/clang/lib/Lex/TokenLexer.cpp b/clang/lib/Lex/TokenLexer.cpp new file mode 100644 index 0000000000000..da5681aaf4784 --- /dev/null +++ b/clang/lib/Lex/TokenLexer.cpp @@ -0,0 +1,1079 @@ +//===- TokenLexer.cpp - Lex from a token stream ---------------------------===// +// +// 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 +// +//===----------------------------------------------------------------------===// +// +// This file implements the TokenLexer interface. +// +//===----------------------------------------------------------------------===// + +#include "clang/Lex/TokenLexer.h" +#include "clang/Basic/Diagnostic.h" +#include "clang/Basic/IdentifierTable.h" +#include "clang/Basic/LangOptions.h" +#include "clang/Basic/SourceLocation.h" +#include "clang/Basic/SourceManager.h" +#include "clang/Basic/TokenKinds.h" +#include "clang/Lex/LexDiagnostic.h" +#include "clang/Lex/Lexer.h" +#include "clang/Lex/MacroArgs.h" +#include "clang/Lex/MacroInfo.h" +#include "clang/Lex/Preprocessor.h" +#include "clang/Lex/Token.h" +#include "clang/Lex/VariadicMacroSupport.h" +#include "llvm/ADT/ArrayRef.h" +#include "llvm/ADT/SmallString.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/iterator_range.h" +#include <cassert> +#include <cstring> + +using namespace clang; + +/// Create a TokenLexer for the specified macro with the specified actual +/// arguments. Note that this ctor takes ownership of the ActualArgs pointer. +void TokenLexer::Init(Token &Tok, SourceLocation ELEnd, MacroInfo *MI, + MacroArgs *Actuals) { + // If the client is reusing a TokenLexer, make sure to free any memory + // associated with it. + destroy(); + + Macro = MI; + ActualArgs = Actuals; + CurTokenIdx = 0; + + ExpandLocStart = Tok.getLocation(); + ExpandLocEnd = ELEnd; + AtStartOfLine = Tok.isAtStartOfLine(); + HasLeadingSpace = Tok.hasLeadingSpace(); + NextTokGetsSpace = false; + Tokens = &*Macro->tokens_begin(); + OwnsTokens = false; + DisableMacroExpansion = false; + IsReinject = false; + NumTokens = Macro->tokens_end()-Macro->tokens_begin(); + MacroExpansionStart = SourceLocation(); + + SourceManager &SM = PP.getSourceManager(); + MacroStartSLocOffset = SM.getNextLocalOffset(); + + if (NumTokens > 0) { + assert(Tokens[0].getLocation().isValid()); + assert((Tokens[0].getLocation().isFileID() || Tokens[0].is(tok::comment)) && + "Macro defined in macro?"); + assert(ExpandLocStart.isValid()); + + // Reserve a source location entry chunk for the length of the macro + // definition. Tokens that get lexed directly from the definition will + // have their locations pointing inside this chunk. This is to avoid + // creating separate source location entries for each token. + MacroDefStart = SM.getExpansionLoc(Tokens[0].getLocation()); + MacroDefLength = Macro->getDefinitionLength(SM); + MacroExpansionStart = SM.createExpansionLoc(MacroDefStart, + ExpandLocStart, + ExpandLocEnd, + MacroDefLength); + } + + // If this is a function-like macro, expand the arguments and change + // Tokens to point to the expanded tokens. + if (Macro->isFunctionLike() && Macro->getNumParams()) + ExpandFunctionArguments(); + + // Mark the macro as currently disabled, so that it is not recursively + // expanded. The macro must be disabled only after argument pre-expansion of + // function-like macro arguments occurs. + Macro->DisableMacro(); +} + +/// Create a TokenLexer for the specified token stream. This does not +/// take ownership of the specified token vector. +void TokenLexer::Init(const Token *TokArray, unsigned NumToks, + bool disableMacroExpansion, bool ownsTokens, + bool isReinject) { + assert(!isReinject || disableMacroExpansion); + // If the client is reusing a TokenLexer, make sure to free any memory + // associated with it. + destroy(); + + Macro = nullptr; + ActualArgs = nullptr; + Tokens = TokArray; + OwnsTokens = ownsTokens; + DisableMacroExpansion = disableMacroExpansion; + IsReinject = isReinject; + NumTokens = NumToks; + CurTokenIdx = 0; + ExpandLocStart = ExpandLocEnd = SourceLocation(); + AtStartOfLine = false; + HasLeadingSpace = false; + NextTokGetsSpace = false; + MacroExpansionStart = SourceLocation(); + + // Set HasLeadingSpace/AtStartOfLine so that the first token will be + // returned unmodified. + if (NumToks != 0) { + AtStartOfLine = TokArray[0].isAtStartOfLine(); + HasLeadingSpace = TokArray[0].hasLeadingSpace(); + } +} + +void TokenLexer::destroy() { + // If this was a function-like macro that actually uses its arguments, delete + // the expanded tokens. + if (OwnsTokens) { + delete [] Tokens; + Tokens = nullptr; + OwnsTokens = false; + } + + // TokenLexer owns its formal arguments. + if (ActualArgs) ActualArgs->destroy(PP); +} + +bool TokenLexer::MaybeRemoveCommaBeforeVaArgs( + SmallVectorImpl<Token> &ResultToks, bool HasPasteOperator, MacroInfo *Macro, + unsigned MacroArgNo, Preprocessor &PP) { + // Is the macro argument __VA_ARGS__? + if (!Macro->isVariadic() || MacroArgNo != Macro->getNumParams()-1) + return false; + + // In Microsoft-compatibility mode, a comma is removed in the expansion + // of " ... , __VA_ARGS__ " if __VA_ARGS__ is empty. This extension is + // not supported by gcc. + if (!HasPasteOperator && !PP.getLangOpts().MSVCCompat) + return false; + + // GCC removes the comma in the expansion of " ... , ## __VA_ARGS__ " if + // __VA_ARGS__ is empty, but not in strict C99 mode where there are no + // named arguments, where it remains. In all other modes, including C99 + // with GNU extensions, it is removed regardless of named arguments. + // Microsoft also appears to support this extension, unofficially. + if (PP.getLangOpts().C99 && !PP.getLangOpts().GNUMode + && Macro->getNumParams() < 2) + return false; + + // Is a comma available to be removed? + if (ResultToks.empty() || !ResultToks.back().is(tok::comma)) + return false; + + // Issue an extension diagnostic for the paste operator. + if (HasPasteOperator) + PP.Diag(ResultToks.back().getLocation(), diag::ext_paste_comma); + + // Remove the comma. + ResultToks.pop_back(); + + if (!ResultToks.empty()) { + // If the comma was right after another paste (e.g. "X##,##__VA_ARGS__"), + // then removal of the comma should produce a placemarker token (in C99 + // terms) which we model by popping off the previous ##, giving us a plain + // "X" when __VA_ARGS__ is empty. + if (ResultToks.back().is(tok::hashhash)) + ResultToks.pop_back(); + + // Remember that this comma was elided. + ResultToks.back().setFlag(Token::CommaAfterElided); + } + + // Never add a space, even if the comma, ##, or arg had a space. + NextTokGetsSpace = false; + return true; +} + +void TokenLexer::stringifyVAOPTContents( + SmallVectorImpl<Token> &ResultToks, const VAOptExpansionContext &VCtx, + const SourceLocation VAOPTClosingParenLoc) { + const int NumToksPriorToVAOpt = VCtx.getNumberOfTokensPriorToVAOpt(); + const unsigned int NumVAOptTokens = ResultToks.size() - NumToksPriorToVAOpt; + Token *const VAOPTTokens = + NumVAOptTokens ? &ResultToks[NumToksPriorToVAOpt] : nullptr; + + SmallVector<Token, 64> ConcatenatedVAOPTResultToks; + // FIXME: Should we keep track within VCtx that we did or didnot + // encounter pasting - and only then perform this loop. + + // Perform token pasting (concatenation) prior to stringization. + for (unsigned int CurTokenIdx = 0; CurTokenIdx != NumVAOptTokens; + ++CurTokenIdx) { + if (VAOPTTokens[CurTokenIdx].is(tok::hashhash)) { + assert(CurTokenIdx != 0 && + "Can not have __VAOPT__ contents begin with a ##"); + Token &LHS = VAOPTTokens[CurTokenIdx - 1]; + pasteTokens(LHS, llvm::makeArrayRef(VAOPTTokens, NumVAOptTokens), + CurTokenIdx); + // Replace the token prior to the first ## in this iteration. + ConcatenatedVAOPTResultToks.back() = LHS; + if (CurTokenIdx == NumVAOptTokens) + break; + } + ConcatenatedVAOPTResultToks.push_back(VAOPTTokens[CurTokenIdx]); + } + + ConcatenatedVAOPTResultToks.push_back(VCtx.getEOFTok()); + // Get the SourceLocation that represents the start location within + // the macro definition that marks where this string is substituted + // into: i.e. the __VA_OPT__ and the ')' within the spelling of the + // macro definition, and use it to indicate that the stringified token + // was generated from that location. + const SourceLocation ExpansionLocStartWithinMacro = + getExpansionLocForMacroDefLoc(VCtx.getVAOptLoc()); + const SourceLocation ExpansionLocEndWithinMacro = + getExpansionLocForMacroDefLoc(VAOPTClosingParenLoc); + + Token StringifiedVAOPT = MacroArgs::StringifyArgument( + &ConcatenatedVAOPTResultToks[0], PP, VCtx.hasCharifyBefore() /*Charify*/, + ExpansionLocStartWithinMacro, ExpansionLocEndWithinMacro); + + if (VCtx.getLeadingSpaceForStringifiedToken()) + StringifiedVAOPT.setFlag(Token::LeadingSpace); + + StringifiedVAOPT.setFlag(Token::StringifiedInMacro); + // Resize (shrink) the token stream to just capture this stringified token. + ResultToks.resize(NumToksPriorToVAOpt + 1); + ResultToks.back() = StringifiedVAOPT; +} + +/// Expand the arguments of a function-like macro so that we can quickly +/// return preexpanded tokens from Tokens. +void TokenLexer::ExpandFunctionArguments() { + SmallVector<Token, 128> ResultToks; + + // Loop through 'Tokens', expanding them into ResultToks. Keep + // track of whether we change anything. If not, no need to keep them. If so, + // we install the newly expanded sequence as the new 'Tokens' list. + bool MadeChange = false; + + Optional<bool> CalledWithVariadicArguments; + + VAOptExpansionContext VCtx(PP); + + for (unsigned I = 0, E = NumTokens; I != E; ++I) { + const Token &CurTok = Tokens[I]; + // We don't want a space for the next token after a paste + // operator. In valid code, the token will get smooshed onto the + // preceding one anyway. In assembler-with-cpp mode, invalid + // pastes are allowed through: in this case, we do not want the + // extra whitespace to be added. For example, we want ". ## foo" + // -> ".foo" not ". foo". + if (I != 0 && !Tokens[I-1].is(tok::hashhash) && CurTok.hasLeadingSpace()) + NextTokGetsSpace = true; + + if (VCtx.isVAOptToken(CurTok)) { + MadeChange = true; + assert(Tokens[I + 1].is(tok::l_paren) && + "__VA_OPT__ must be followed by '('"); + + ++I; // Skip the l_paren + VCtx.sawVAOptFollowedByOpeningParens(CurTok.getLocation(), + ResultToks.size()); + + continue; + } + + // We have entered into the __VA_OPT__ context, so handle tokens + // appropriately. + if (VCtx.isInVAOpt()) { + // If we are about to process a token that is either an argument to + // __VA_OPT__ or its closing rparen, then: + // 1) If the token is the closing rparen that exits us out of __VA_OPT__, + // perform any necessary stringification or placemarker processing, + // and/or skip to the next token. + // 2) else if macro was invoked without variadic arguments skip this + // token. + // 3) else (macro was invoked with variadic arguments) process the token + // normally. + + if (Tokens[I].is(tok::l_paren)) + VCtx.sawOpeningParen(Tokens[I].getLocation()); + // Continue skipping tokens within __VA_OPT__ if the macro was not + // called with variadic arguments, else let the rest of the loop handle + // this token. Note sawClosingParen() returns true only if the r_paren matches + // the closing r_paren of the __VA_OPT__. + if (!Tokens[I].is(tok::r_paren) || !VCtx.sawClosingParen()) { + // Lazily expand __VA_ARGS__ when we see the first __VA_OPT__. + if (!CalledWithVariadicArguments.hasValue()) { + CalledWithVariadicArguments = + ActualArgs->invokedWithVariadicArgument(Macro, PP); + } + if (!*CalledWithVariadicArguments) { + // Skip this token. + continue; + } + // ... else the macro was called with variadic arguments, and we do not + // have a closing rparen - so process this token normally. + } else { + // Current token is the closing r_paren which marks the end of the + // __VA_OPT__ invocation, so handle any place-marker pasting (if + // empty) by removing hashhash either before (if exists) or after. And + // also stringify the entire contents if VAOPT was preceded by a hash, + // but do so only after any token concatenation that needs to occur + // within the contents of VAOPT. + + if (VCtx.hasStringifyOrCharifyBefore()) { + // Replace all the tokens just added from within VAOPT into a single + // stringified token. This requires token-pasting to eagerly occur + // within these tokens. If either the contents of VAOPT were empty + // or the macro wasn't called with any variadic arguments, the result + // is a token that represents an empty string. + stringifyVAOPTContents(ResultToks, VCtx, + /*ClosingParenLoc*/ Tokens[I].getLocation()); + + } else if (/*No tokens within VAOPT*/ + ResultToks.size() == VCtx.getNumberOfTokensPriorToVAOpt()) { + // Treat VAOPT as a placemarker token. Eat either the '##' before the + // RHS/VAOPT (if one exists, suggesting that the LHS (if any) to that + // hashhash was not a placemarker) or the '##' + // after VAOPT, but not both. + + if (ResultToks.size() && ResultToks.back().is(tok::hashhash)) { + ResultToks.pop_back(); + } else if ((I + 1 != E) && Tokens[I + 1].is(tok::hashhash)) { + ++I; // Skip the following hashhash. + } + } else { + // If there's a ## before the __VA_OPT__, we might have discovered + // that the __VA_OPT__ begins with a placeholder. We delay action on + // that to now to avoid messing up our stashed count of tokens before + // __VA_OPT__. + if (VCtx.beginsWithPlaceholder()) { + assert(VCtx.getNumberOfTokensPriorToVAOpt() > 0 && + ResultToks.size() >= VCtx.getNumberOfTokensPriorToVAOpt() && + ResultToks[VCtx.getNumberOfTokensPriorToVAOpt() - 1].is( + tok::hashhash) && + "no token paste before __VA_OPT__"); + ResultToks.erase(ResultToks.begin() + + VCtx.getNumberOfTokensPriorToVAOpt() - 1); + } + // If the expansion of __VA_OPT__ ends with a placeholder, eat any + // following '##' token. + if (VCtx.endsWithPlaceholder() && I + 1 != E && + Tokens[I + 1].is(tok::hashhash)) { + ++I; + } + } + VCtx.reset(); + // We processed __VA_OPT__'s closing paren (and the exit out of + // __VA_OPT__), so skip to the next token. + continue; + } + } + + // If we found the stringify operator, get the argument stringified. The + // preprocessor already verified that the following token is a macro + // parameter or __VA_OPT__ when the #define was lexed. + + if (CurTok.isOneOf(tok::hash, tok::hashat)) { + int ArgNo = Macro->getParameterNum(Tokens[I+1].getIdentifierInfo()); + assert((ArgNo != -1 || VCtx.isVAOptToken(Tokens[I + 1])) && + "Token following # is not an argument or __VA_OPT__!"); + + if (ArgNo == -1) { + // Handle the __VA_OPT__ case. + VCtx.sawHashOrHashAtBefore(NextTokGetsSpace, + CurTok.is(tok::hashat)); + continue; + } + // Else handle the simple argument case. + SourceLocation ExpansionLocStart = + getExpansionLocForMacroDefLoc(CurTok.getLocation()); + SourceLocation ExpansionLocEnd = + getExpansionLocForMacroDefLoc(Tokens[I+1].getLocation()); + + bool Charify = CurTok.is(tok::hashat); + const Token *UnexpArg = ActualArgs->getUnexpArgument(ArgNo); + Token Res = MacroArgs::StringifyArgument( + UnexpArg, PP, Charify, ExpansionLocStart, ExpansionLocEnd); + Res.setFlag(Token::StringifiedInMacro); + + // The stringified/charified string leading space flag gets set to match + // the #/#@ operator. + if (NextTokGetsSpace) + Res.setFlag(Token::LeadingSpace); + + ResultToks.push_back(Res); + MadeChange = true; + ++I; // Skip arg name. + NextTokGetsSpace = false; + continue; + } + + // Find out if there is a paste (##) operator before or after the token. + bool NonEmptyPasteBefore = + !ResultToks.empty() && ResultToks.back().is(tok::hashhash); + bool PasteBefore = I != 0 && Tokens[I-1].is(tok::hashhash); + bool PasteAfter = I+1 != E && Tokens[I+1].is(tok::hashhash); + bool RParenAfter = I+1 != E && Tokens[I+1].is(tok::r_paren); + + assert((!NonEmptyPasteBefore || PasteBefore || VCtx.isInVAOpt()) && + "unexpected ## in ResultToks"); + + // Otherwise, if this is not an argument token, just add the token to the + // output buffer. + IdentifierInfo *II = CurTok.getIdentifierInfo(); + int ArgNo = II ? Macro->getParameterNum(II) : -1; + if (ArgNo == -1) { + // This isn't an argument, just add it. + ResultToks.push_back(CurTok); + + if (NextTokGetsSpace) { + ResultToks.back().setFlag(Token::LeadingSpace); + NextTokGetsSpace = false; + } else if (PasteBefore && !NonEmptyPasteBefore) + ResultToks.back().clearFlag(Token::LeadingSpace); + + continue; + } + + // An argument is expanded somehow, the result is different than the + // input. + MadeChange = true; + + // Otherwise, this is a use of the argument. + + // In Microsoft mode, remove the comma before __VA_ARGS__ to ensure there + // are no trailing commas if __VA_ARGS__ is empty. + if (!PasteBefore && ActualArgs->isVarargsElidedUse() && + MaybeRemoveCommaBeforeVaArgs(ResultToks, + /*HasPasteOperator=*/false, + Macro, ArgNo, PP)) + continue; + + // If it is not the LHS/RHS of a ## operator, we must pre-expand the + // argument and substitute the expanded tokens into the result. This is + // C99 6.10.3.1p1. + if (!PasteBefore && !PasteAfter) { + const Token *ResultArgToks; + + // Only preexpand the argument if it could possibly need it. This + // avoids some work in common cases. + const Token *ArgTok = ActualArgs->getUnexpArgument(ArgNo); + if (ActualArgs->ArgNeedsPreexpansion(ArgTok, PP)) + ResultArgToks = &ActualArgs->getPreExpArgument(ArgNo, PP)[0]; + else + ResultArgToks = ArgTok; // Use non-preexpanded tokens. + + // If the arg token expanded into anything, append it. + if (ResultArgToks->isNot(tok::eof)) { + size_t FirstResult = ResultToks.size(); + unsigned NumToks = MacroArgs::getArgLength(ResultArgToks); + ResultToks.append(ResultArgToks, ResultArgToks+NumToks); + + // In Microsoft-compatibility mode, we follow MSVC's preprocessing + // behavior by not considering single commas from nested macro + // expansions as argument separators. Set a flag on the token so we can + // test for this later when the macro expansion is processed. + if (PP.getLangOpts().MSVCCompat && NumToks == 1 && + ResultToks.back().is(tok::comma)) + ResultToks.back().setFlag(Token::IgnoredComma); + + // If the '##' came from expanding an argument, turn it into 'unknown' + // to avoid pasting. + for (Token &Tok : llvm::make_range(ResultToks.begin() + FirstResult, + ResultToks.end())) { + if (Tok.is(tok::hashhash)) + Tok.setKind(tok::unknown); + } + + if(ExpandLocStart.isValid()) { + updateLocForMacroArgTokens(CurTok.getLocation(), + ResultToks.begin()+FirstResult, + ResultToks.end()); + } + + // If any tokens were substituted from the argument, the whitespace + // before the first token should match the whitespace of the arg + // identifier. + ResultToks[FirstResult].setFlagValue(Token::LeadingSpace, + NextTokGetsSpace); + ResultToks[FirstResult].setFlagValue(Token::StartOfLine, false); + NextTokGetsSpace = false; + } else { + // We're creating a placeholder token. Usually this doesn't matter, + // but it can affect paste behavior when at the start or end of a + // __VA_OPT__. + if (NonEmptyPasteBefore) { + // We're imagining a placeholder token is inserted here. If this is + // the first token in a __VA_OPT__ after a ##, delete the ##. + assert(VCtx.isInVAOpt() && "should only happen inside a __VA_OPT__"); + VCtx.hasPlaceholderAfterHashhashAtStart(); + } + if (RParenAfter) + VCtx.hasPlaceholderBeforeRParen(); + } + continue; + } + + // Okay, we have a token that is either the LHS or RHS of a paste (##) + // argument. It gets substituted as its non-pre-expanded tokens. + const Token *ArgToks = ActualArgs->getUnexpArgument(ArgNo); + unsigned NumToks = MacroArgs::getArgLength(ArgToks); + if (NumToks) { // Not an empty argument? + bool VaArgsPseudoPaste = false; + // If this is the GNU ", ## __VA_ARGS__" extension, and we just learned + // that __VA_ARGS__ expands to multiple tokens, avoid a pasting error when + // the expander tries to paste ',' with the first token of the __VA_ARGS__ + // expansion. + if (NonEmptyPasteBefore && ResultToks.size() >= 2 && + ResultToks[ResultToks.size()-2].is(tok::comma) && + (unsigned)ArgNo == Macro->getNumParams()-1 && + Macro->isVariadic()) { + VaArgsPseudoPaste = true; + // Remove the paste operator, report use of the extension. + PP.Diag(ResultToks.pop_back_val().getLocation(), diag::ext_paste_comma); + } + + ResultToks.append(ArgToks, ArgToks+NumToks); + + // If the '##' came from expanding an argument, turn it into 'unknown' + // to avoid pasting. + for (Token &Tok : llvm::make_range(ResultToks.end() - NumToks, + ResultToks.end())) { + if (Tok.is(tok::hashhash)) + Tok.setKind(tok::unknown); + } + + if (ExpandLocStart.isValid()) { + updateLocForMacroArgTokens(CurTok.getLocation(), + ResultToks.end()-NumToks, ResultToks.end()); + } + + // Transfer the leading whitespace information from the token + // (the macro argument) onto the first token of the + // expansion. Note that we don't do this for the GNU + // pseudo-paste extension ", ## __VA_ARGS__". + if (!VaArgsPseudoPaste) { + ResultToks[ResultToks.size() - NumToks].setFlagValue(Token::StartOfLine, + false); + ResultToks[ResultToks.size() - NumToks].setFlagValue( + Token::LeadingSpace, NextTokGetsSpace); + } + + NextTokGetsSpace = false; + continue; + } + + // If an empty argument is on the LHS or RHS of a paste, the standard (C99 + // 6.10.3.3p2,3) calls for a bunch of placemarker stuff to occur. We + // implement this by eating ## operators when a LHS or RHS expands to + // empty. + if (PasteAfter) { + // Discard the argument token and skip (don't copy to the expansion + // buffer) the paste operator after it. + ++I; + continue; + } + + if (RParenAfter) + VCtx.hasPlaceholderBeforeRParen(); + + // If this is on the RHS of a paste operator, we've already copied the + // paste operator to the ResultToks list, unless the LHS was empty too. + // Remove it. + assert(PasteBefore); + if (NonEmptyPasteBefore) { + assert(ResultToks.back().is(tok::hashhash)); + // Do not remove the paste operator if it is the one before __VA_OPT__ + // (and we are still processing tokens within VA_OPT). We handle the case + // of removing the paste operator if __VA_OPT__ reduces to the notional + // placemarker above when we encounter the closing paren of VA_OPT. + if (!VCtx.isInVAOpt() || + ResultToks.size() > VCtx.getNumberOfTokensPriorToVAOpt()) + ResultToks.pop_back(); + else + VCtx.hasPlaceholderAfterHashhashAtStart(); + } + + // If this is the __VA_ARGS__ token, and if the argument wasn't provided, + // and if the macro had at least one real argument, and if the token before + // the ## was a comma, remove the comma. This is a GCC extension which is + // disabled when using -std=c99. + if (ActualArgs->isVarargsElidedUse()) + MaybeRemoveCommaBeforeVaArgs(ResultToks, + /*HasPasteOperator=*/true, + Macro, ArgNo, PP); + } + + // If anything changed, install this as the new Tokens list. + if (MadeChange) { + assert(!OwnsTokens && "This would leak if we already own the token list"); + // This is deleted in the dtor. + NumTokens = ResultToks.size(); + // The tokens will be added to Preprocessor's cache and will be removed + // when this TokenLexer finishes lexing them. + Tokens = PP.cacheMacroExpandedTokens(this, ResultToks); + + // The preprocessor cache of macro expanded tokens owns these tokens,not us. + OwnsTokens = false; + } +} + +/// Checks if two tokens form wide string literal. +static bool isWideStringLiteralFromMacro(const Token &FirstTok, + const Token &SecondTok) { + return FirstTok.is(tok::identifier) && + FirstTok.getIdentifierInfo()->isStr("L") && SecondTok.isLiteral() && + SecondTok.stringifiedInMacro(); +} + +/// Lex - Lex and return a token from this macro stream. +bool TokenLexer::Lex(Token &Tok) { + // Lexing off the end of the macro, pop this macro off the expansion stack. + if (isAtEnd()) { + // If this is a macro (not a token stream), mark the macro enabled now + // that it is no longer being expanded. + if (Macro) Macro->EnableMacro(); + + Tok.startToken(); + Tok.setFlagValue(Token::StartOfLine , AtStartOfLine); + Tok.setFlagValue(Token::LeadingSpace, HasLeadingSpace || NextTokGetsSpace); + if (CurTokenIdx == 0) + Tok.setFlag(Token::LeadingEmptyMacro); + return PP.HandleEndOfTokenLexer(Tok); + } + + SourceManager &SM = PP.getSourceManager(); + + // If this is the first token of the expanded result, we inherit spacing + // properties later. + bool isFirstToken = CurTokenIdx == 0; + + // Get the next token to return. + Tok = Tokens[CurTokenIdx++]; + if (IsReinject) + Tok.setFlag(Token::IsReinjected); + + bool TokenIsFromPaste = false; + + // If this token is followed by a token paste (##) operator, paste the tokens! + // Note that ## is a normal token when not expanding a macro. + if (!isAtEnd() && Macro && + (Tokens[CurTokenIdx].is(tok::hashhash) || + // Special processing of L#x macros in -fms-compatibility mode. + // Microsoft compiler is able to form a wide string literal from + // 'L#macro_arg' construct in a function-like macro. + (PP.getLangOpts().MSVCCompat && + isWideStringLiteralFromMacro(Tok, Tokens[CurTokenIdx])))) { + // When handling the microsoft /##/ extension, the final token is + // returned by pasteTokens, not the pasted token. + if (pasteTokens(Tok)) + return true; + + TokenIsFromPaste = true; + } + + // The token's current location indicate where the token was lexed from. We + // need this information to compute the spelling of the token, but any + // diagnostics for the expanded token should appear as if they came from + // ExpansionLoc. Pull this information together into a new SourceLocation + // that captures all of this. + if (ExpandLocStart.isValid() && // Don't do this for token streams. + // Check that the token's location was not already set properly. + SM.isBeforeInSLocAddrSpace(Tok.getLocation(), MacroStartSLocOffset)) { + SourceLocation instLoc; + if (Tok.is(tok::comment)) { + instLoc = SM.createExpansionLoc(Tok.getLocation(), + ExpandLocStart, + ExpandLocEnd, + Tok.getLength()); + } else { + instLoc = getExpansionLocForMacroDefLoc(Tok.getLocation()); + } + + Tok.setLocation(instLoc); + } + + // If this is the first token, set the lexical properties of the token to + // match the lexical properties of the macro identifier. + if (isFirstToken) { + Tok.setFlagValue(Token::StartOfLine , AtStartOfLine); + Tok.setFlagValue(Token::LeadingSpace, HasLeadingSpace); + } else { + // If this is not the first token, we may still need to pass through + // leading whitespace if we've expanded a macro. + if (AtStartOfLine) Tok.setFlag(Token::StartOfLine); + if (HasLeadingSpace) Tok.setFlag(Token::LeadingSpace); + } + AtStartOfLine = false; + HasLeadingSpace = false; + + // Handle recursive expansion! + if (!Tok.isAnnotation() && Tok.getIdentifierInfo() != nullptr) { + // Change the kind of this identifier to the appropriate token kind, e.g. + // turning "for" into a keyword. + IdentifierInfo *II = Tok.getIdentifierInfo(); + Tok.setKind(II->getTokenID()); + + // If this identifier was poisoned and from a paste, emit an error. This + // won't be handled by Preprocessor::HandleIdentifier because this is coming + // from a macro expansion. + if (II->isPoisoned() && TokenIsFromPaste) { + PP.HandlePoisonedIdentifier(Tok); + } + + if (!DisableMacroExpansion && II->isHandleIdentifierCase()) + return PP.HandleIdentifier(Tok); + } + + // Otherwise, return a normal token. + return true; +} + +bool TokenLexer::pasteTokens(Token &Tok) { + return pasteTokens(Tok, llvm::makeArrayRef(Tokens, NumTokens), CurTokenIdx); +} + +/// LHSTok is the LHS of a ## operator, and CurTokenIdx is the ## +/// operator. Read the ## and RHS, and paste the LHS/RHS together. If there +/// are more ## after it, chomp them iteratively. Return the result as LHSTok. +/// If this returns true, the caller should immediately return the token. +bool TokenLexer::pasteTokens(Token &LHSTok, ArrayRef<Token> TokenStream, + unsigned int &CurIdx) { + assert(CurIdx > 0 && "## can not be the first token within tokens"); + assert((TokenStream[CurIdx].is(tok::hashhash) || + (PP.getLangOpts().MSVCCompat && + isWideStringLiteralFromMacro(LHSTok, TokenStream[CurIdx]))) && + "Token at this Index must be ## or part of the MSVC 'L " + "#macro-arg' pasting pair"); + + // MSVC: If previous token was pasted, this must be a recovery from an invalid + // paste operation. Ignore spaces before this token to mimic MSVC output. + // Required for generating valid UUID strings in some MS headers. + if (PP.getLangOpts().MicrosoftExt && (CurIdx >= 2) && + TokenStream[CurIdx - 2].is(tok::hashhash)) + LHSTok.clearFlag(Token::LeadingSpace); + + SmallString<128> Buffer; + const char *ResultTokStrPtr = nullptr; + SourceLocation StartLoc = LHSTok.getLocation(); + SourceLocation PasteOpLoc; + + auto IsAtEnd = [&TokenStream, &CurIdx] { + return TokenStream.size() == CurIdx; + }; + + do { + // Consume the ## operator if any. + PasteOpLoc = TokenStream[CurIdx].getLocation(); + if (TokenStream[CurIdx].is(tok::hashhash)) + ++CurIdx; + assert(!IsAtEnd() && "No token on the RHS of a paste operator!"); + + // Get the RHS token. + const Token &RHS = TokenStream[CurIdx]; + + // Allocate space for the result token. This is guaranteed to be enough for + // the two tokens. + Buffer.resize(LHSTok.getLength() + RHS.getLength()); + + // Get the spelling of the LHS token in Buffer. + const char *BufPtr = &Buffer[0]; + bool Invalid = false; + unsigned LHSLen = PP.getSpelling(LHSTok, BufPtr, &Invalid); + if (BufPtr != &Buffer[0]) // Really, we want the chars in Buffer! + memcpy(&Buffer[0], BufPtr, LHSLen); + if (Invalid) + return true; + + BufPtr = Buffer.data() + LHSLen; + unsigned RHSLen = PP.getSpelling(RHS, BufPtr, &Invalid); + if (Invalid) + return true; + if (RHSLen && BufPtr != &Buffer[LHSLen]) + // Really, we want the chars in Buffer! + memcpy(&Buffer[LHSLen], BufPtr, RHSLen); + + // Trim excess space. + Buffer.resize(LHSLen+RHSLen); + + // Plop the pasted result (including the trailing newline and null) into a + // scratch buffer where we can lex it. + Token ResultTokTmp; + ResultTokTmp.startToken(); + + // Claim that the tmp token is a string_literal so that we can get the + // character pointer back from CreateString in getLiteralData(). + ResultTokTmp.setKind(tok::string_literal); + PP.CreateString(Buffer, ResultTokTmp); + SourceLocation ResultTokLoc = ResultTokTmp.getLocation(); + ResultTokStrPtr = ResultTokTmp.getLiteralData(); + + // Lex the resultant pasted token into Result. + Token Result; + + if (LHSTok.isAnyIdentifier() && RHS.isAnyIdentifier()) { + // Common paste case: identifier+identifier = identifier. Avoid creating + // a lexer and other overhead. + PP.IncrementPasteCounter(true); + Result.startToken(); + Result.setKind(tok::raw_identifier); + Result.setRawIdentifierData(ResultTokStrPtr); + Result.setLocation(ResultTokLoc); + Result.setLength(LHSLen+RHSLen); + } else { + PP.IncrementPasteCounter(false); + + assert(ResultTokLoc.isFileID() && + "Should be a raw location into scratch buffer"); + SourceManager &SourceMgr = PP.getSourceManager(); + FileID LocFileID = SourceMgr.getFileID(ResultTokLoc); + + bool Invalid = false; + const char *ScratchBufStart + = SourceMgr.getBufferData(LocFileID, &Invalid).data(); + if (Invalid) + return false; + + // Make a lexer to lex this string from. Lex just this one token. + // Make a lexer object so that we lex and expand the paste result. + Lexer TL(SourceMgr.getLocForStartOfFile(LocFileID), + PP.getLangOpts(), ScratchBufStart, + ResultTokStrPtr, ResultTokStrPtr+LHSLen+RHSLen); + + // Lex a token in raw mode. This way it won't look up identifiers + // automatically, lexing off the end will return an eof token, and + // warnings are disabled. This returns true if the result token is the + // entire buffer. + bool isInvalid = !TL.LexFromRawLexer(Result); + + // If we got an EOF token, we didn't form even ONE token. For example, we + // did "/ ## /" to get "//". + isInvalid |= Result.is(tok::eof); + + // If pasting the two tokens didn't form a full new token, this is an + // error. This occurs with "x ## +" and other stuff. Return with LHSTok + // unmodified and with RHS as the next token to lex. + if (isInvalid) { + // Explicitly convert the token location to have proper expansion + // information so that the user knows where it came from. + SourceManager &SM = PP.getSourceManager(); + SourceLocation Loc = + SM.createExpansionLoc(PasteOpLoc, ExpandLocStart, ExpandLocEnd, 2); + + // Test for the Microsoft extension of /##/ turning into // here on the + // error path. + if (PP.getLangOpts().MicrosoftExt && LHSTok.is(tok::slash) && + RHS.is(tok::slash)) { + HandleMicrosoftCommentPaste(LHSTok, Loc); + return true; + } + + // Do not emit the error when preprocessing assembler code. + if (!PP.getLangOpts().AsmPreprocessor) { + // If we're in microsoft extensions mode, downgrade this from a hard + // error to an extension that defaults to an error. This allows + // disabling it. + PP.Diag(Loc, PP.getLangOpts().MicrosoftExt ? diag::ext_pp_bad_paste_ms + : diag::err_pp_bad_paste) + << Buffer; + } + + // An error has occurred so exit loop. + break; + } + + // Turn ## into 'unknown' to avoid # ## # from looking like a paste + // operator. + if (Result.is(tok::hashhash)) + Result.setKind(tok::unknown); + } + + // Transfer properties of the LHS over the Result. + Result.setFlagValue(Token::StartOfLine , LHSTok.isAtStartOfLine()); + Result.setFlagValue(Token::LeadingSpace, LHSTok.hasLeadingSpace()); + + // Finally, replace LHS with the result, consume the RHS, and iterate. + ++CurIdx; + LHSTok = Result; + } while (!IsAtEnd() && TokenStream[CurIdx].is(tok::hashhash)); + + SourceLocation EndLoc = TokenStream[CurIdx - 1].getLocation(); + + // The token's current location indicate where the token was lexed from. We + // need this information to compute the spelling of the token, but any + // diagnostics for the expanded token should appear as if the token was + // expanded from the full ## expression. Pull this information together into + // a new SourceLocation that captures all of this. + SourceManager &SM = PP.getSourceManager(); + if (StartLoc.isFileID()) + StartLoc = getExpansionLocForMacroDefLoc(StartLoc); + if (EndLoc.isFileID()) + EndLoc = getExpansionLocForMacroDefLoc(EndLoc); + FileID MacroFID = SM.getFileID(MacroExpansionStart); + while (SM.getFileID(StartLoc) != MacroFID) + StartLoc = SM.getImmediateExpansionRange(StartLoc).getBegin(); + while (SM.getFileID(EndLoc) != MacroFID) + EndLoc = SM.getImmediateExpansionRange(EndLoc).getEnd(); + + LHSTok.setLocation(SM.createExpansionLoc(LHSTok.getLocation(), StartLoc, EndLoc, + LHSTok.getLength())); + + // Now that we got the result token, it will be subject to expansion. Since + // token pasting re-lexes the result token in raw mode, identifier information + // isn't looked up. As such, if the result is an identifier, look up id info. + if (LHSTok.is(tok::raw_identifier)) { + // Look up the identifier info for the token. We disabled identifier lookup + // by saying we're skipping contents, so we need to do this manually. + PP.LookUpIdentifierInfo(LHSTok); + } + return false; +} + +/// isNextTokenLParen - If the next token lexed will pop this macro off the +/// expansion stack, return 2. If the next unexpanded token is a '(', return +/// 1, otherwise return 0. +unsigned TokenLexer::isNextTokenLParen() const { + // Out of tokens? + if (isAtEnd()) + return 2; + return Tokens[CurTokenIdx].is(tok::l_paren); +} + +/// isParsingPreprocessorDirective - Return true if we are in the middle of a +/// preprocessor directive. +bool TokenLexer::isParsingPreprocessorDirective() const { + return Tokens[NumTokens-1].is(tok::eod) && !isAtEnd(); +} + +/// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes +/// together to form a comment that comments out everything in the current +/// macro, other active macros, and anything left on the current physical +/// source line of the expanded buffer. Handle this by returning the +/// first token on the next line. +void TokenLexer::HandleMicrosoftCommentPaste(Token &Tok, SourceLocation OpLoc) { + PP.Diag(OpLoc, diag::ext_comment_paste_microsoft); + + // We 'comment out' the rest of this macro by just ignoring the rest of the + // tokens that have not been lexed yet, if any. + + // Since this must be a macro, mark the macro enabled now that it is no longer + // being expanded. + assert(Macro && "Token streams can't paste comments"); + Macro->EnableMacro(); + + PP.HandleMicrosoftCommentPaste(Tok); +} + +/// If \arg loc is a file ID and points inside the current macro +/// definition, returns the appropriate source location pointing at the +/// macro expansion source location entry, otherwise it returns an invalid +/// SourceLocation. +SourceLocation +TokenLexer::getExpansionLocForMacroDefLoc(SourceLocation loc) const { + assert(ExpandLocStart.isValid() && MacroExpansionStart.isValid() && + "Not appropriate for token streams"); + assert(loc.isValid() && loc.isFileID()); + + SourceManager &SM = PP.getSourceManager(); + assert(SM.isInSLocAddrSpace(loc, MacroDefStart, MacroDefLength) && + "Expected loc to come from the macro definition"); + + unsigned relativeOffset = 0; + SM.isInSLocAddrSpace(loc, MacroDefStart, MacroDefLength, &relativeOffset); + return MacroExpansionStart.getLocWithOffset(relativeOffset); +} + +/// Finds the tokens that are consecutive (from the same FileID) +/// creates a single SLocEntry, and assigns SourceLocations to each token that +/// point to that SLocEntry. e.g for +/// assert(foo == bar); +/// There will be a single SLocEntry for the "foo == bar" chunk and locations +/// for the 'foo', '==', 'bar' tokens will point inside that chunk. +/// +/// \arg begin_tokens will be updated to a position past all the found +/// consecutive tokens. +static void updateConsecutiveMacroArgTokens(SourceManager &SM, + SourceLocation InstLoc, + Token *&begin_tokens, + Token * end_tokens) { + assert(begin_tokens < end_tokens); + + SourceLocation FirstLoc = begin_tokens->getLocation(); + SourceLocation CurLoc = FirstLoc; + + // Compare the source location offset of tokens and group together tokens that + // are close, even if their locations point to different FileIDs. e.g. + // + // |bar | foo | cake | (3 tokens from 3 consecutive FileIDs) + // ^ ^ + // |bar foo cake| (one SLocEntry chunk for all tokens) + // + // we can perform this "merge" since the token's spelling location depends + // on the relative offset. + + Token *NextTok = begin_tokens + 1; + for (; NextTok < end_tokens; ++NextTok) { + SourceLocation NextLoc = NextTok->getLocation(); + if (CurLoc.isFileID() != NextLoc.isFileID()) + break; // Token from different kind of FileID. + + int RelOffs; + if (!SM.isInSameSLocAddrSpace(CurLoc, NextLoc, &RelOffs)) + break; // Token from different local/loaded location. + // Check that token is not before the previous token or more than 50 + // "characters" away. + if (RelOffs < 0 || RelOffs > 50) + break; + + if (CurLoc.isMacroID() && !SM.isWrittenInSameFile(CurLoc, NextLoc)) + break; // Token from a different macro. + + CurLoc = NextLoc; + } + + // For the consecutive tokens, find the length of the SLocEntry to contain + // all of them. + Token &LastConsecutiveTok = *(NextTok-1); + int LastRelOffs = 0; + SM.isInSameSLocAddrSpace(FirstLoc, LastConsecutiveTok.getLocation(), + &LastRelOffs); + unsigned FullLength = LastRelOffs + LastConsecutiveTok.getLength(); + + // Create a macro expansion SLocEntry that will "contain" all of the tokens. + SourceLocation Expansion = + SM.createMacroArgExpansionLoc(FirstLoc, InstLoc,FullLength); + + // Change the location of the tokens from the spelling location to the new + // expanded location. + for (; begin_tokens < NextTok; ++begin_tokens) { + Token &Tok = *begin_tokens; + int RelOffs = 0; + SM.isInSameSLocAddrSpace(FirstLoc, Tok.getLocation(), &RelOffs); + Tok.setLocation(Expansion.getLocWithOffset(RelOffs)); + } +} + +/// Creates SLocEntries and updates the locations of macro argument +/// tokens to their new expanded locations. +/// +/// \param ArgIdSpellLoc the location of the macro argument id inside the macro +/// definition. +void TokenLexer::updateLocForMacroArgTokens(SourceLocation ArgIdSpellLoc, + Token *begin_tokens, + Token *end_tokens) { + SourceManager &SM = PP.getSourceManager(); + + SourceLocation InstLoc = + getExpansionLocForMacroDefLoc(ArgIdSpellLoc); + + while (begin_tokens < end_tokens) { + // If there's only one token just create a SLocEntry for it. + if (end_tokens - begin_tokens == 1) { + Token &Tok = *begin_tokens; + Tok.setLocation(SM.createMacroArgExpansionLoc(Tok.getLocation(), + InstLoc, + Tok.getLength())); + return; + } + + updateConsecutiveMacroArgTokens(SM, InstLoc, begin_tokens, end_tokens); + } +} + +void TokenLexer::PropagateLineStartLeadingSpaceInfo(Token &Result) { + AtStartOfLine = Result.isAtStartOfLine(); + HasLeadingSpace = Result.hasLeadingSpace(); +} |