Nice; one question though: I suspect this is not the only place we are doing such things. Did you audit Sema at all for this kind of stuff?
We have -suppress-system-warnings=false to show when we are emitting diagnostics that get ignored, but there is no way to see places where we do needless computation without manual inspection... - Daniel On Fri, Jan 16, 2009 at 11:50 AM, Chris Lattner <sa...@nondot.org> wrote: > Author: lattner > Date: Fri Jan 16 13:50:11 2009 > New Revision: 62347 > > URL: http://llvm.org/viewvc/llvm-project?rev=62347&view=rev > Log: > As a performance optimization, don't bother calling MacroInfo::isIdenticalTo > if warnings in system headers are disabled. isIdenticalTo can end up > calling the expensive getSpelling method, and other bad stuff and is > completely unneeded if the warning will be discarded anyway. rdar://6502956 > > Modified: > cfe/trunk/lib/Lex/PPDirectives.cpp > > Modified: cfe/trunk/lib/Lex/PPDirectives.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Lex/PPDirectives.cpp?rev=62347&r1=62346&r2=62347&view=diff > > ============================================================================== > --- cfe/trunk/lib/Lex/PPDirectives.cpp (original) > +++ cfe/trunk/lib/Lex/PPDirectives.cpp Fri Jan 16 13:50:11 2009 > @@ -1060,16 +1060,23 @@ > // Finally, if this identifier already had a macro defined for it, verify > that > // the macro bodies are identical and free the old definition. > if (MacroInfo *OtherMI = getMacroInfo(MacroNameTok.getIdentifierInfo())) { > - if (!OtherMI->isUsed()) > - Diag(OtherMI->getDefinitionLoc(), diag::pp_macro_not_used); > - > - // Macros must be identical. This means all tokes and whitespace > separation > - // must be the same. C99 6.10.3.2. > - if (!MI->isIdenticalTo(*OtherMI, *this)) { > - Diag(MI->getDefinitionLoc(), diag::ext_pp_macro_redef) > - << MacroNameTok.getIdentifierInfo(); > - Diag(OtherMI->getDefinitionLoc(), diag::note_previous_definition); > + // It is very common for system headers to have tons of macro > redefinitions > + // and for warnings to be disabled in system headers. If this is the > case, > + // then don't bother calling MacroInfo::isIdenticalTo. > + if (!Diags.getSuppressSystemWarnings() || > + !SourceMgr.isInSystemHeader(DefineTok.getLocation())) { > + if (!OtherMI->isUsed()) > + Diag(OtherMI->getDefinitionLoc(), diag::pp_macro_not_used); > + > + // Macros must be identical. This means all tokes and whitespace > + // separation must be the same. C99 6.10.3.2. > + if (!MI->isIdenticalTo(*OtherMI, *this)) { > + Diag(MI->getDefinitionLoc(), diag::ext_pp_macro_redef) > + << MacroNameTok.getIdentifierInfo(); > + Diag(OtherMI->getDefinitionLoc(), diag::note_previous_definition); > + } > } > + > ReleaseMacroInfo(OtherMI); > } > > > > _______________________________________________ > cfe-commits mailing list > cfe-commits@cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits > _______________________________________________ cfe-commits mailing list cfe-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
