When determining whether a variable is a file-scoped variable, check
out its lookup context (to see through linkage
specifications). Addresses <rdar://problem/6477142>.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@61848 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index f5f57b4..5b96153 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -428,8 +428,8 @@
   bool isFileVarDecl() const {
     if (getKind() != Decl::Var)
       return false;
-    if (isa<TranslationUnitDecl>(getDeclContext()) ||
-        isa<NamespaceDecl>(getDeclContext()) )
+    const DeclContext *Ctx = getDeclContext()->getLookupContext();
+    if (isa<TranslationUnitDecl>(Ctx) || isa<NamespaceDecl>(Ctx) )
       return true;
     return false;
   }
diff --git a/include/clang/AST/DeclBase.h b/include/clang/AST/DeclBase.h
index 255067b..e9b309b 100644
--- a/include/clang/AST/DeclBase.h
+++ b/include/clang/AST/DeclBase.h
@@ -429,7 +429,11 @@
   /// context of this context, which corresponds to the innermost
   /// location from which name lookup can find the entities in this
   /// context.
-  DeclContext *getLookupContext();
+  DeclContext *getLookupContext() {
+    return const_cast<DeclContext *>(
+             const_cast<const DeclContext *>(this)->getLookupContext());
+  }
+  const DeclContext *getLookupContext() const;
 
   /// getNextContext - If this is a DeclContext that may have other
   /// DeclContexts that are semantically connected but syntactically
diff --git a/lib/AST/DeclBase.cpp b/lib/AST/DeclBase.cpp
index cf612c2..f14dc3c 100644
--- a/lib/AST/DeclBase.cpp
+++ b/lib/AST/DeclBase.cpp
@@ -567,8 +567,8 @@
   return const_cast<DeclContext*>(this)->lookup(Context, Name);
 }
 
-DeclContext *DeclContext::getLookupContext() {
-  DeclContext *Ctx = this;
+const DeclContext *DeclContext::getLookupContext() const {
+  const DeclContext *Ctx = this;
   while (Ctx->isTransparentContext())
     Ctx = Ctx->getParent();
   return Ctx;
diff --git a/test/SemaCXX/linkage-spec.cpp b/test/SemaCXX/linkage-spec.cpp
index 80d95fb..6f25da0 100644
--- a/test/SemaCXX/linkage-spec.cpp
+++ b/test/SemaCXX/linkage-spec.cpp
@@ -15,3 +15,9 @@
   int& i1 = g(x);
   double& d1 = g(d);
 }
+
+extern "C" int foo;
+extern "C" int foo;
+
+extern "C" const int bar;
+extern "C" int const bar;