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Diffstat (limited to 'lib/Lex/TokenLexer.cpp')
| -rw-r--r-- | lib/Lex/TokenLexer.cpp | 542 |
1 files changed, 542 insertions, 0 deletions
diff --git a/lib/Lex/TokenLexer.cpp b/lib/Lex/TokenLexer.cpp new file mode 100644 index 0000000..f9f9386 --- /dev/null +++ b/lib/Lex/TokenLexer.cpp @@ -0,0 +1,542 @@ +//===--- TokenLexer.cpp - Lex from a token stream -------------------------===// +// +// 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 TokenLexer interface. +// +//===----------------------------------------------------------------------===// + +#include "clang/Lex/TokenLexer.h" +#include "MacroArgs.h" +#include "clang/Lex/MacroInfo.h" +#include "clang/Lex/Preprocessor.h" +#include "clang/Basic/SourceManager.h" +#include "clang/Lex/LexDiagnostic.h" +#include "llvm/ADT/SmallVector.h" +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 ILEnd, MacroArgs *Actuals) { + // If the client is reusing a TokenLexer, make sure to free any memory + // associated with it. + destroy(); + + Macro = PP.getMacroInfo(Tok.getIdentifierInfo()); + ActualArgs = Actuals; + CurToken = 0; + + InstantiateLocStart = Tok.getLocation(); + InstantiateLocEnd = ILEnd; + AtStartOfLine = Tok.isAtStartOfLine(); + HasLeadingSpace = Tok.hasLeadingSpace(); + Tokens = &*Macro->tokens_begin(); + OwnsTokens = false; + DisableMacroExpansion = false; + NumTokens = Macro->tokens_end()-Macro->tokens_begin(); + + // If this is a function-like macro, expand the arguments and change + // Tokens to point to the expanded tokens. + if (Macro->isFunctionLike() && Macro->getNumArgs()) + 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) { + // If the client is reusing a TokenLexer, make sure to free any memory + // associated with it. + destroy(); + + Macro = 0; + ActualArgs = 0; + Tokens = TokArray; + OwnsTokens = ownsTokens; + DisableMacroExpansion = disableMacroExpansion; + NumTokens = NumToks; + CurToken = 0; + InstantiateLocStart = InstantiateLocEnd = SourceLocation(); + AtStartOfLine = false; + HasLeadingSpace = false; + + // 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 = 0; + OwnsTokens = false; + } + + // TokenLexer owns its formal arguments. + if (ActualArgs) ActualArgs->destroy(); +} + +/// Expand the arguments of a function-like macro so that we can quickly +/// return preexpanded tokens from Tokens. +void TokenLexer::ExpandFunctionArguments() { + llvm::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; + + // NextTokGetsSpace - When this is true, the next token appended to the + // output list will get a leading space, regardless of whether it had one to + // begin with or not. This is used for placemarker support. + bool NextTokGetsSpace = false; + + for (unsigned i = 0, e = NumTokens; i != e; ++i) { + // If we found the stringify operator, get the argument stringified. The + // preprocessor already verified that the following token is a macro name + // when the #define was parsed. + const Token &CurTok = Tokens[i]; + if (CurTok.is(tok::hash) || CurTok.is(tok::hashat)) { + int ArgNo = Macro->getArgumentNum(Tokens[i+1].getIdentifierInfo()); + assert(ArgNo != -1 && "Token following # is not an argument?"); + + Token Res; + if (CurTok.is(tok::hash)) // Stringify + Res = ActualArgs->getStringifiedArgument(ArgNo, PP); + else { + // 'charify': don't bother caching these. + Res = MacroArgs::StringifyArgument(ActualArgs->getUnexpArgument(ArgNo), + PP, true); + } + + // The stringified/charified string leading space flag gets set to match + // the #/#@ operator. + if (CurTok.hasLeadingSpace() || NextTokGetsSpace) + Res.setFlag(Token::LeadingSpace); + + ResultToks.push_back(Res); + MadeChange = true; + ++i; // Skip arg name. + NextTokGetsSpace = false; + continue; + } + + // Otherwise, if this is not an argument token, just add the token to the + // output buffer. + IdentifierInfo *II = CurTok.getIdentifierInfo(); + int ArgNo = II ? Macro->getArgumentNum(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; + } + continue; + } + + // An argument is expanded somehow, the result is different than the + // input. + MadeChange = true; + + // Otherwise, this is a use of the argument. Find out if there is a paste + // (##) operator before or after the argument. + bool PasteBefore = + !ResultToks.empty() && ResultToks.back().is(tok::hashhash); + bool PasteAfter = i+1 != e && Tokens[i+1].is(tok::hashhash); + + // 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)) { + unsigned FirstResult = ResultToks.size(); + unsigned NumToks = MacroArgs::getArgLength(ResultArgToks); + ResultToks.append(ResultArgToks, ResultArgToks+NumToks); + + // 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, + CurTok.hasLeadingSpace() || + NextTokGetsSpace); + NextTokGetsSpace = false; + } else { + // If this is an empty argument, and if there was whitespace before the + // formal token, make sure the next token gets whitespace before it. + NextTokGetsSpace = CurTok.hasLeadingSpace(); + } + 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? + // If this is the GNU ", ## __VA_ARG__" extension, and we just learned + // that __VA_ARG__ expands to multiple tokens, avoid a pasting error when + // the expander trys to paste ',' with the first token of the __VA_ARG__ + // expansion. + if (PasteBefore && ResultToks.size() >= 2 && + ResultToks[ResultToks.size()-2].is(tok::comma) && + (unsigned)ArgNo == Macro->getNumArgs()-1 && + Macro->isVariadic()) { + // Remove the paste operator, report use of the extension. + PP.Diag(ResultToks.back().getLocation(), diag::ext_paste_comma); + ResultToks.pop_back(); + } + + ResultToks.append(ArgToks, ArgToks+NumToks); + + // If this token (the macro argument) was supposed to get leading + // whitespace, transfer this information onto the first token of the + // expansion. + // + // Do not do this if the paste operator occurs before the macro argument, + // as in "A ## MACROARG". In valid code, the first token will get + // smooshed onto the preceding one anyway (forming AMACROARG). 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 ((CurTok.hasLeadingSpace() || NextTokGetsSpace) && + !PasteBefore) + ResultToks[ResultToks.size()-NumToks].setFlag(Token::LeadingSpace); + + 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. + NextTokGetsSpace |= CurTok.hasLeadingSpace(); + if (PasteAfter) { + // Discard the argument token and skip (don't copy to the expansion + // buffer) the paste operator after it. + NextTokGetsSpace |= Tokens[i+1].hasLeadingSpace(); + ++i; + continue; + } + + // If this is on the RHS of a paste operator, we've already copied the + // paste operator to the ResultToks list. Remove it. + assert(PasteBefore && ResultToks.back().is(tok::hashhash)); + NextTokGetsSpace |= ResultToks.back().hasLeadingSpace(); + ResultToks.pop_back(); + + // 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. + if ((unsigned)ArgNo == Macro->getNumArgs()-1 && // is __VA_ARGS__ + ActualArgs->isVarargsElidedUse() && // Argument elided. + !ResultToks.empty() && ResultToks.back().is(tok::comma)) { + // Never add a space, even if the comma, ##, or arg had a space. + NextTokGetsSpace = false; + // Remove the paste operator, report use of the extension. + PP.Diag(ResultToks.back().getLocation(), diag::ext_paste_comma); + ResultToks.pop_back(); + } + continue; + } + + // 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(); + llvm::BumpPtrAllocator &Alloc = PP.getPreprocessorAllocator(); + Token *Res = + static_cast<Token *>(Alloc.Allocate(sizeof(Token)*ResultToks.size(), + llvm::alignof<Token>())); + if (NumTokens) + memcpy(Res, &ResultToks[0], NumTokens*sizeof(Token)); + Tokens = Res; + + // The preprocessor bump pointer owns these tokens, not us. + OwnsTokens = false; + } +} + +/// Lex - Lex and return a token from this macro stream. +/// +void 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(); + + // Pop this context off the preprocessors lexer stack and get the next + // token. This will delete "this" so remember the PP instance var. + Preprocessor &PPCache = PP; + if (PP.HandleEndOfTokenLexer(Tok)) + return; + + // HandleEndOfTokenLexer may not return a token. If it doesn't, lex + // whatever is next. + return PPCache.Lex(Tok); + } + + // If this is the first token of the expanded result, we inherit spacing + // properties later. + bool isFirstToken = CurToken == 0; + + // Get the next token to return. + Tok = Tokens[CurToken++]; + + bool TokenIsFromPaste = false; + + // If this token is followed by a token paste (##) operator, paste the tokens! + if (!isAtEnd() && Tokens[CurToken].is(tok::hashhash)) { + if (PasteTokens(Tok)) { + // When handling the microsoft /##/ extension, the final token is + // returned by PasteTokens, not the pasted token. + return; + } else { + 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 + // InstantiationLoc. Pull this information together into a new SourceLocation + // that captures all of this. + if (InstantiateLocStart.isValid()) { // Don't do this for token streams. + SourceManager &SM = PP.getSourceManager(); + Tok.setLocation(SM.createInstantiationLoc(Tok.getLocation(), + InstantiateLocStart, + InstantiateLocEnd, + Tok.getLength())); + } + + // 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); + } + + // Handle recursive expansion! + if (!Tok.isAnnotation() && Tok.getIdentifierInfo() != 0) { + // 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) { + // We warn about __VA_ARGS__ with poisoning. + if (II->isStr("__VA_ARGS__")) + PP.Diag(Tok, diag::ext_pp_bad_vaargs_use); + else + PP.Diag(Tok, diag::err_pp_used_poisoned_id); + } + + if (!DisableMacroExpansion && II->isHandleIdentifierCase()) + PP.HandleIdentifier(Tok); + } + + // Otherwise, return a normal token. +} + +/// PasteTokens - Tok is the LHS of a ## operator, and CurToken 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 Tok. +/// If this returns true, the caller should immediately return the token. +bool TokenLexer::PasteTokens(Token &Tok) { + llvm::SmallVector<char, 128> Buffer; + const char *ResultTokStrPtr = 0; + do { + // Consume the ## operator. + SourceLocation PasteOpLoc = Tokens[CurToken].getLocation(); + ++CurToken; + assert(!isAtEnd() && "No token on the RHS of a paste operator!"); + + // Get the RHS token. + const Token &RHS = Tokens[CurToken]; + + // Allocate space for the result token. This is guaranteed to be enough for + // the two tokens. + Buffer.resize(Tok.getLength() + RHS.getLength()); + + // Get the spelling of the LHS token in Buffer. + const char *BufPtr = &Buffer[0]; + unsigned LHSLen = PP.getSpelling(Tok, BufPtr); + if (BufPtr != &Buffer[0]) // Really, we want the chars in Buffer! + memcpy(&Buffer[0], BufPtr, LHSLen); + + BufPtr = &Buffer[LHSLen]; + unsigned RHSLen = PP.getSpelling(RHS, BufPtr); + if (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. + ResultTokTmp.setKind(tok::string_literal); + PP.CreateString(&Buffer[0], Buffer.size(), ResultTokTmp); + SourceLocation ResultTokLoc = ResultTokTmp.getLocation(); + ResultTokStrPtr = ResultTokTmp.getLiteralData(); + + // Lex the resultant pasted token into Result. + Token Result; + + if (Tok.is(tok::identifier) && RHS.is(tok::identifier)) { + // Common paste case: identifier+identifier = identifier. Avoid creating + // a lexer and other overhead. + PP.IncrementPasteCounter(true); + Result.startToken(); + Result.setKind(tok::identifier); + 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); + + const char *ScratchBufStart = SourceMgr.getBufferData(LocFileID).first; + + // 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.getLangOptions(), 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 Tok + // unmodified and with RHS as the next token to lex. + if (isInvalid) { + // Test for the Microsoft extension of /##/ turning into // here on the + // error path. + if (PP.getLangOptions().Microsoft && Tok.is(tok::slash) && + RHS.is(tok::slash)) { + HandleMicrosoftCommentPaste(Tok); + return true; + } + + // Do not emit the warning when preprocessing assembler code. + if (!PP.getLangOptions().AsmPreprocessor) { + // Explicitly convert the token location to have proper instantiation + // information so that the user knows where it came from. + SourceManager &SM = PP.getSourceManager(); + SourceLocation Loc = + SM.createInstantiationLoc(PasteOpLoc, InstantiateLocStart, + InstantiateLocEnd, 2); + PP.Diag(Loc, diag::err_pp_bad_paste) + << std::string(Buffer.begin(), Buffer.end()); + } + + // Do not consume the RHS. + --CurToken; + } + + // 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 the Result. + Result.setFlagValue(Token::StartOfLine , Tok.isAtStartOfLine()); + Result.setFlagValue(Token::LeadingSpace, Tok.hasLeadingSpace()); + + // Finally, replace LHS with the result, consume the RHS, and iterate. + ++CurToken; + Tok = Result; + } while (!isAtEnd() && Tokens[CurToken].is(tok::hashhash)); + + // 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 (Tok.is(tok::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. + IdentifierInfo *II = PP.LookUpIdentifierInfo(Tok, ResultTokStrPtr); + Tok.setIdentifierInfo(II); + } + 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[CurToken].is(tok::l_paren); +} + + +/// 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 instantiated buffer. Handle this by returning the +/// first token on the next line. +void TokenLexer::HandleMicrosoftCommentPaste(Token &Tok) { + // 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); +} |
