blob: 194ceecc0708b52147fde4d27ee2371ebf87cde4 [file] [log] [blame]
//===--- 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 "clang/Basic/SourceManager.h"
#include "clang/Lex/LexDiagnostic.h"
#include "clang/Lex/MacroArgs.h"
#include "clang/Lex/MacroInfo.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/VariadicMacroSupport.h"
#include "llvm/ADT/SmallString.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 ELEnd, MacroInfo *MI,
MacroArgs *Actuals) {
// If the client is reusing a TokenLexer, make sure to free any memory
// associated with it.
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;
NumTokens = Macro->tokens_end()-Macro->tokens_begin();
MacroExpansionStart = SourceLocation();
SourceManager &SM = PP.getSourceManager();
MacroStartSLocOffset = SM.getNextLocalOffset();
if (NumTokens > 0) {
assert((Tokens[0].getLocation().isFileID() || Tokens[0].is(tok::comment)) &&
"Macro defined in macro?");
// 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,
// If this is a function-like macro, expand the arguments and change
// Tokens to point to the expanded tokens.
if (Macro->isFunctionLike() && Macro->getNumParams())
// 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.
/// 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.
Macro = nullptr;
ActualArgs = nullptr;
Tokens = TokArray;
OwnsTokens = ownsTokens;
DisableMacroExpansion = disableMacroExpansion;
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.
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))
// Remember that this comma was elided.
// 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),
// Replace the token prior to the first ## in this iteration.
ConcatenatedVAOPTResultToks.back() = LHS;
if (CurTokenIdx == NumVAOptTokens)
// 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 =
const SourceLocation ExpansionLocEndWithinMacro =
Token StringifiedVAOPT = MacroArgs::StringifyArgument(
&ConcatenatedVAOPTResultToks[0], PP, VCtx.hasCharifyBefore() /*Charify*/,
ExpansionLocStartWithinMacro, ExpansionLocEndWithinMacro);
if (VCtx.getLeadingSpaceForStringifiedToken())
// 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;
const 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
// 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))
// 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()) {
if (!CalledWithVariadicArguments) {
// Skip this token.
// ... 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)) {
} else if ((I + 1 != E) && Tokens[I + 1].is(tok::hashhash)) {
++I; // Skip the following hashhash.
// We processed __VA_OPT__'s closing paren (and the exit out of
// __VA_OPT__), so skip to the next token.
// 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.
// Else handle the simple argument case.
SourceLocation ExpansionLocStart =
SourceLocation ExpansionLocEnd =
Token Res;
if ( // 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 (NextTokGetsSpace)
MadeChange = true;
++I; // Skip arg name.
NextTokGetsSpace = false;
// 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);
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.
if (NextTokGetsSpace) {
NextTokGetsSpace = false;
} else if (PasteBefore && !NonEmptyPasteBefore)
// 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() &&
Macro, ArgNo, PP))
// 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
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];
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 &&
// 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 (
if(ExpandLocStart.isValid()) {
// 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::StartOfLine, false);
NextTokGetsSpace = false;
// 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 trys 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 (
if (ExpandLocStart.isValid()) {
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,
ResultToks[ResultToks.size() - NumToks].setFlagValue(
Token::LeadingSpace, NextTokGetsSpace);
NextTokGetsSpace = false;
// If an empty argument is on the LHS or RHS of a paste, the standard (C99
//,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.
// 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.
if (NonEmptyPasteBefore) {
// 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())
// 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())
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;
/// \brief Checks if two tokens form wide string literal.
static bool isWideStringLiteralFromMacro(const Token &FirstTok,
const Token &SecondTok) {
return &&
FirstTok.getIdentifierInfo()->isStr("L") && SecondTok.isLiteral() &&
/// 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.setFlagValue(Token::StartOfLine , AtStartOfLine);
Tok.setFlagValue(Token::LeadingSpace, HasLeadingSpace || NextTokGetsSpace);
if (CurTokenIdx == 0)
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++];
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 ( {
instLoc = SM.createExpansionLoc(Tok.getLocation(),
} else {
instLoc = getExpansionLocForMacroDefLoc(Tok.getLocation());
// 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();
// 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) {
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))
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))
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 = + 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.
// Plop the pasted result (including the trailing newline and null) into a
// scratch buffer where we can lex it.
Token ResultTokTmp;
// Claim that the tmp token is a string_literal so that we can get the
// character pointer back from CreateString in getLiteralData().
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.
} else {
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 |=;
// 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 && && {
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.
// Turn ## into 'unknown' to avoid # ## # from looking like a paste
// operator.
if (
// 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.
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).first;
while (SM.getFileID(EndLoc) != MacroFID)
EndLoc = SM.getImmediateExpansionRange(EndLoc).second;
LHSTok.setLocation(SM.createExpansionLoc(LHSTok.getLocation(), StartLoc, EndLoc,
// 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 ( {
// 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.
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");
/// \brief 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.
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);
/// \brief 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)
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(),
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);
/// \brief 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 =
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;
updateConsecutiveMacroArgTokens(SM, InstLoc, begin_tokens, end_tokens);
void TokenLexer::PropagateLineStartLeadingSpaceInfo(Token &Result) {
AtStartOfLine = Result.isAtStartOfLine();
HasLeadingSpace = Result.hasLeadingSpace();