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Lex: Require that '#' be followed by a macro parameter name when preceded by '##' 

After lexing a '##', we would look ahead and check to see if it was
followed by '__VA_ARGS__'.  After doing so, we would then go ahead and
lex the token.

However we would fail in the case where the '##' was followed by a '#'
followed by an identifier because we would have lexed the '#' separately
from the identifier, bypassing our parameter validation logic.

Instead, lex the tokens coming after the '##' later.

This fixes PR17804.

llvm-svn: 194059
This commit is contained in:
David Majnemer 2013-11-05 09:30:17 +00:00
parent 04a0e5050f
commit 76faf1f525
2 changed files with 3 additions and 6 deletions
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7
clang/lib/Lex/PPDirectives.cpp
View File

@ -2005,13 +2005,8 @@ void Preprocessor::HandleDefineDirective(Token &DefineTok,
MI->getReplacementToken(NumTokens-1).is(tok::comma)) MI->getReplacementToken(NumTokens-1).is(tok::comma))
MI->setHasCommaPasting(); MI->setHasCommaPasting();
// Things look ok, add the '##' and param name tokens to the macro. // Things look ok, add the '##' token to the macro.
MI->AddTokenToBody(LastTok); MI->AddTokenToBody(LastTok);
MI->AddTokenToBody(Tok);
LastTok = Tok;
// Get the next token of the macro.
LexUnexpandedToken(Tok);
continue; continue;
} }

2
clang/test/Preprocessor/macro_paste_bad.c
View File

@ -32,3 +32,5 @@ XX // expected-error {{attempt to use a poisoned identifier}}
#define VA __VA_ ## ARGS__ #define VA __VA_ ## ARGS__
int VA; // expected-warning {{__VA_ARGS__ can only appear in the expansion of a C99 variadic macro}} int VA; // expected-warning {{__VA_ARGS__ can only appear in the expansion of a C99 variadic macro}}
#define LOG_ON_ERROR(lvl) ::X x## #__LINE__; // expected-error {{'#' is not followed by a macro parameter}}
LOG_ON_ERROR(0);