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Fix a bug where we would incorrectly emit a "cannot paste" error 

message when handling the GNU ", ## __VA_ARGS__" extension.  While
I'm at it, flag uses of this as extensions.

llvm-svn: 46503
This commit is contained in:
Chris Lattner 2008-01-29 07:54:23 +00:00
parent 361de6164d
commit 0c8a1edb8b
2 changed files with 29 additions and 1 deletions
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17
clang/Lex/MacroExpander.cpp
View File

@ -409,6 +409,19 @@ void MacroExpander::ExpandFunctionArguments() {
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 the next token was supposed to get leading whitespace, ensure it has
@ -447,6 +460,8 @@ void MacroExpander::ExpandFunctionArguments() {
!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;
@ -615,7 +630,7 @@ void MacroExpander::PasteTokens(Token &Tok) {
// Turn ## into 'other' to avoid # ## # from looking like a paste operator.
if (Result.is(tok::hashhash))
Result.setKind(tok::unknown);
// FIXME: Turn __VARRGS__ into "not a token"?
// FIXME: Turn __VA_ARGS__ into "not a token"?
// Transfer properties of the LHS over the the Result.
Result.setFlagValue(Token::StartOfLine , Tok.isAtStartOfLine());

13
clang/test/Preprocessor/macro_paste_commaext.c Normal file
View File

@ -0,0 +1,13 @@
// RUN: clang %s -E | grep 'V);' &&
// RUN: clang %s -E | grep 'W, 1, 2);'
// RUN: clang %s -E | grep 'X, 1, 2);'
// RUN: clang %s -E | grep 'Y, );'
// RUN: clang %s -E | grep 'Z, );'
#define debug(format, ...) format, ## __VA_ARGS__)
debug(V);
debug(W, 1, 2);
debug(X, 1, 2 );
debug(Y, );
debug(Z,);