[cfe-commits] [PATCH] Revert predefined tracking

[Jordan Rose]

Looks good to me now, go ahead and commit!

(We still do have top-level declarations in the predefines for MS mode and ARC-under-libstdc++, but both of those are C++-only so this change shouldn't break anything.)


On Jun 19, 2012, at 8:54 , Meador Inge <meadori at codesourcery.com> wrote:

> 
> On Jun 18, 2012, at 12:26 PM, Jordan Rose wrote:
> 
>> Hi, Meador. Now that we don't need two loops, I think it would be cleaner to use an explicit if for the first decl, then a do-while loop to process them all. That way the WarnOnEmptyTU flag goes away. (But don't forget to only warn in non-C++ mode.)
> 
> 
> Ah, great point.  So something more like (we still need a flag in spirit for the preprocessed header check):
> 
> Index: lib/Parse/ParseAST.cpp
> ===================================================================
> --- lib/Parse/ParseAST.cpp	(revision 158702)
> +++ lib/Parse/ParseAST.cpp	(working copy)
> @@ -83,46 +83,24 @@
>   // declaration. C++ doesn't have this restriction. We also don't want to
>   // complain if we have a precompiled header, although technically if the PCH
>   // is empty we should still emit the (pedantic) diagnostic.
> -  bool WarnForEmptyTU = !S.getLangOpts().CPlusPlus;
> -  if (ExternalASTSource *External = S.getASTContext().getExternalSource()) {
> -    External->StartTranslationUnit(Consumer);
> -    WarnForEmptyTU = false;
> -  }
> -
> -  // Clang's predefines contain top-level declarations for things like va_list,
> -  // making it hard to tell if the /user's/ translation unit has at least one
> -  // top-level declaration. So we parse cautiously, looking for a declaration
> -  // that doesn't come from our predefines.
> -  // Note that ParseTopLevelDecl returns 'true' at EOF.
> -  SourceManager &SM = S.getSourceManager();
>   Parser::DeclGroupPtrTy ADecl;
> -  while (WarnForEmptyTU && !P.ParseTopLevelDecl(ADecl)) {
> -    if (ADecl) {
> -      if (!Consumer->HandleTopLevelDecl(ADecl.get()))
> -        return;
> -      if (DeclGroupRef::iterator FirstDecl = ADecl.get().begin()) {
> -        SourceLocation DeclLoc = (*FirstDecl)->getLocation();
> -        WarnForEmptyTU = SM.isFromPredefines(DeclLoc);
> -      }
> -    }
> -  }
> +  ExternalASTSource *External = S.getASTContext().getExternalSource();
> +  if (External)
> +    External->StartTranslationUnit(Consumer);
> 
> -  // If we ended up seeing EOF before any top-level declarations, emit our
> -  // diagnostic. Otherwise, parse the rest of the file normally.
> -  if (WarnForEmptyTU) {
> -    P.Diag(diag::ext_empty_translation_unit);
> +  if (P.ParseTopLevelDecl(ADecl)) {
> +    if (!External && !S.getLangOpts().CPlusPlus)
> +      P.Diag(diag::ext_empty_translation_unit);
>   } else {
> -    while (!P.ParseTopLevelDecl(ADecl)) {  // Not end of file.
> +    do {
>       // If we got a null return and something *was* parsed, ignore it.  This
>       // is due to a top-level semicolon, an action override, or a parse error
>       // skipping something.
> -      if (ADecl) {
> -        if (!Consumer->HandleTopLevelDecl(ADecl.get())) 
> -          return;
> -      }
> -    };
> +      if (ADecl && !Consumer->HandleTopLevelDecl(ADecl.get()))
> +	return;
> +    } while (!P.ParseTopLevelDecl(ADecl));
>   }
> -  
> +
>   // Process any TopLevelDecls generated by #pragma weak.
>   for (SmallVector<Decl*,2>::iterator
>        I = S.WeakTopLevelDecls().begin(),
> 
> 
> Meador Inge
> CodeSourcery / Mentor Embedded
> http://www.mentor.com/embedded-software
>