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//===--- 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 "MacroArgs.h"
#include "clang/Lex/MacroInfo.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/LexDiagnostic.h"
using namespace clang;
/// MacroArgs ctor function - This destroys the vector passed in.
MacroArgs *MacroArgs::create(const MacroInfo *MI,
const Token *UnexpArgTokens,
unsigned NumToks, bool VarargsElided) {
assert(MI->isFunctionLike() &&
"Can't have args for an object-like macro!");
// Allocate memory for the MacroArgs object with the lexer tokens at the end.
MacroArgs *Result = (MacroArgs*)malloc(sizeof(MacroArgs) +
// Construct the macroargs object.
new (Result) MacroArgs(NumToks, VarargsElided);
// Copy the actual unexpanded tokens to immediately after the result ptr.
if (NumToks)
UnexpArgTokens, NumToks*sizeof(Token));
return Result;
/// destroy - Destroy and deallocate the memory for this object.
void MacroArgs::destroy() {
// Run the dtor to deallocate the vectors.
// Release the memory for the object.
/// getArgLength - Given a pointer to an expanded or unexpanded argument,
/// return the number of tokens, not counting the EOF, that make up the
/// argument.
unsigned MacroArgs::getArgLength(const Token *ArgPtr) {
unsigned NumArgTokens = 0;
for (; ArgPtr->isNot(tok::eof); ++ArgPtr)
return NumArgTokens;
/// getUnexpArgument - Return the unexpanded tokens for the specified formal.
const Token *MacroArgs::getUnexpArgument(unsigned Arg) const {
// The unexpanded argument tokens start immediately after the MacroArgs object
// in memory.
const Token *Start = (const Token *)(this+1);
const Token *Result = Start;
// Scan to find Arg.
for (; Arg; ++Result) {
assert(Result < Start+NumUnexpArgTokens && "Invalid arg #");
if (Result->is(tok::eof))
assert(Result < Start+NumUnexpArgTokens && "Invalid arg #");
return Result;
/// ArgNeedsPreexpansion - If we can prove that the argument won't be affected
/// by pre-expansion, return false. Otherwise, conservatively return true.
bool MacroArgs::ArgNeedsPreexpansion(const Token *ArgTok,
Preprocessor &PP) const {
// If there are no identifiers in the argument list, or if the identifiers are
// known to not be macros, pre-expansion won't modify it.
for (; ArgTok->isNot(tok::eof); ++ArgTok)
if (IdentifierInfo *II = ArgTok->getIdentifierInfo()) {
if (II->hasMacroDefinition() && PP.getMacroInfo(II)->isEnabled())
// Return true even though the macro could be a function-like macro
// without a following '(' token.
return true;
return false;
/// getPreExpArgument - Return the pre-expanded form of the specified
/// argument.
const std::vector<Token> &
MacroArgs::getPreExpArgument(unsigned Arg, Preprocessor &PP) {
assert(Arg < NumUnexpArgTokens && "Invalid argument number!");
// If we have already computed this, return it.
if (PreExpArgTokens.empty())
std::vector<Token> &Result = PreExpArgTokens[Arg];
if (!Result.empty()) return Result;
const Token *AT = getUnexpArgument(Arg);
unsigned NumToks = getArgLength(AT)+1; // Include the EOF.
// Otherwise, we have to pre-expand this argument, populating Result. To do
// this, we set up a fake TokenLexer to lex from the unexpanded argument
// list. With this installed, we lex expanded tokens until we hit the EOF
// token at the end of the unexp list.
PP.EnterTokenStream(AT, NumToks, false /*disable expand*/,
false /*owns tokens*/);
// Lex all of the macro-expanded tokens into Result.
do {
Token &Tok = Result.back();
} while (Result.back().isNot(tok::eof));
// Pop the token stream off the top of the stack. We know that the internal
// pointer inside of it is to the "end" of the token stream, but the stack
// will not otherwise be popped until the next token is lexed. The problem is
// that the token may be lexed sometime after the vector of tokens itself is
// destroyed, which would be badness.
return Result;
/// StringifyArgument - Implement C99, converting a sequence of
/// tokens into the literal string token that should be produced by the C #
/// preprocessor operator. If Charify is true, then it should be turned into
/// a character literal for the Microsoft charize (#@) extension.
Token MacroArgs::StringifyArgument(const Token *ArgToks,
Preprocessor &PP, bool Charify) {
Token Tok;
const Token *ArgTokStart = ArgToks;
// Stringify all the tokens.
llvm::SmallString<128> Result;
Result += "\"";
bool isFirst = true;
for (; ArgToks->isNot(tok::eof); ++ArgToks) {
const Token &Tok = *ArgToks;
if (!isFirst && (Tok.hasLeadingSpace() || Tok.isAtStartOfLine()))
Result += ' ';
isFirst = false;
// If this is a string or character constant, escape the token as specified
// by
if ( || // "foo" || // L"foo" { // 'x' and L'x'.
std::string Str = Lexer::Stringify(PP.getSpelling(Tok));
Result.append(Str.begin(), Str.end());
} else {
// Otherwise, just append the token. Do some gymnastics to get the token
// in place and avoid copies where possible.
unsigned CurStrLen = Result.size();
const char *BufPtr = &Result[CurStrLen];
unsigned ActualTokLen = PP.getSpelling(Tok, BufPtr);
// If getSpelling returned a pointer to an already uniqued version of the
// string instead of filling in BufPtr, memcpy it onto our string.
if (BufPtr != &Result[CurStrLen])
memcpy(&Result[CurStrLen], BufPtr, ActualTokLen);
// If the token was dirty, the spelling may be shorter than the token.
if (ActualTokLen != Tok.getLength())
// If the last character of the string is a \, and if it isn't escaped, this
// is an invalid string literal, diagnose it as specified in C99.
if (Result.back() == '\\') {
// Count the number of consequtive \ characters. If even, then they are
// just escaped backslashes, otherwise it's an error.
unsigned FirstNonSlash = Result.size()-2;
// Guaranteed to find the starting " if nothing else.
while (Result[FirstNonSlash] == '\\')
if ((Result.size()-1-FirstNonSlash) & 1) {
// Diagnose errors for things like: #define F(X) #X / F(\)
PP.Diag(ArgToks[-1], diag::pp_invalid_string_literal);
Result.pop_back(); // remove one of the \'s.
Result += '"';
// If this is the charify operation and the result is not a legal character
// constant, diagnose it.
if (Charify) {
// First step, turn double quotes into single quotes:
Result[0] = '\'';
Result[Result.size()-1] = '\'';
// Check for bogus character.
bool isBad = false;
if (Result.size() == 3)
isBad = Result[1] == '\''; // ''' is not legal. '\' already fixed above.
isBad = (Result.size() != 4 || Result[1] != '\\'); // Not '\x'
if (isBad) {
PP.Diag(ArgTokStart[0], diag::err_invalid_character_to_charify);
Result = "' '"; // Use something arbitrary, but legal.
PP.CreateString(&Result[0], Result.size(), Tok);
return Tok;
/// getStringifiedArgument - Compute, cache, and return the specified argument
/// that has been 'stringified' as required by the # operator.
const Token &MacroArgs::getStringifiedArgument(unsigned ArgNo,
Preprocessor &PP) {
assert(ArgNo < NumUnexpArgTokens && "Invalid argument number!");
if (StringifiedArgs.empty()) {
memset(&StringifiedArgs[0], 0,
if (StringifiedArgs[ArgNo].isNot(tok::string_literal))
StringifiedArgs[ArgNo] = StringifyArgument(getUnexpArgument(ArgNo), PP);
return StringifiedArgs[ArgNo];