r180263 - Fix a case in linkage computation that should check for single line extern "C".

[David Dean]

I'm seeing a crash when building clang on darwin11 after this commit: you can view the builder here:
http://lab.llvm.org:8013/builders/clang-x86_64-darwin11-RA/builds/1711

I've also attached the output files from the crash to try and help you reproduce the issue.

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On 25 Apr 2013, at 6:10 AM, Rafael Espindola <rafael.espindola at gmail.com> wrote:

> Author: rafael
> Date: Thu Apr 25 08:10:46 2013
> New Revision: 180263
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=180263&view=rev
> Log:
> Fix a case in linkage computation that should check for single line extern "C".
> 
> Modified:
>    cfe/trunk/lib/AST/Decl.cpp
>    cfe/trunk/test/SemaCXX/undefined-internal.cpp
> 
> Modified: cfe/trunk/lib/AST/Decl.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Decl.cpp?rev=180263&r1=180262&r2=180263&view=diff
> ==============================================================================
> --- cfe/trunk/lib/AST/Decl.cpp (original)
> +++ cfe/trunk/lib/AST/Decl.cpp Thu Apr 25 08:10:46 2013
> @@ -476,6 +476,13 @@ template <typename T> static bool isInEx
>   return First->getDeclContext()->isExternCContext();
> }
> 
> +static bool isSingleLineExternC(const Decl &D) {
> +  if (const LinkageSpecDecl *SD = dyn_cast<LinkageSpecDecl>(D.getDeclContext()))
> +    if (SD->getLanguage() == LinkageSpecDecl::lang_c && !SD->hasBraces())
> +      return true;
> +  return false;
> +}
> +
> static LinkageInfo getLVForNamespaceScopeDecl(const NamedDecl *D,
>                                               LVComputationKind computation) {
>   assert(D->getDeclContext()->getRedeclContext()->isFileContext() &&
> @@ -504,7 +511,8 @@ static LinkageInfo getLVForNamespaceScop
>         return PrevVar->getLinkageAndVisibility();
> 
>       if (Var->getStorageClass() != SC_Extern &&
> -          Var->getStorageClass() != SC_PrivateExtern)
> +          Var->getStorageClass() != SC_PrivateExtern &&
> +          !isSingleLineExternC(*Var))
>         return LinkageInfo::internal();
>     }
> 
> @@ -1580,11 +1588,8 @@ VarDecl::DefinitionKind VarDecl::isThisD
>   //   A declaration directly contained in a linkage-specification is treated
>   //   as if it contains the extern specifier for the purpose of determining
>   //   the linkage of the declared name and whether it is a definition.
> -  const DeclContext *DC = getDeclContext();
> -  if (const LinkageSpecDecl *SD = dyn_cast<LinkageSpecDecl>(DC)) {
> -    if (SD->getLanguage() == LinkageSpecDecl::lang_c && !SD->hasBraces())
> -      return DeclarationOnly;
> -  }
> +  if (isSingleLineExternC(*this))
> +    return DeclarationOnly;
> 
>   // C99 6.9.2p2:
>   //   A declaration of an object that has file scope without an initializer,
> 
> Modified: cfe/trunk/test/SemaCXX/undefined-internal.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/undefined-internal.cpp?rev=180263&r1=180262&r2=180263&view=diff
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/undefined-internal.cpp (original)
> +++ cfe/trunk/test/SemaCXX/undefined-internal.cpp Thu Apr 25 08:10:46 2013
> @@ -323,3 +323,10 @@ namespace test13 {
>   }
> }
> 
> +namespace test14 {
> +  extern "C" const int foo;
> +
> +  int f() {
> +    return foo;
> +  }
> +}
> 
> 
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-David