Add a getLanguageLinkage method to VarDecls and FunctionDecls. Use it to fix

some cases where functions with no language linkage were being treated as having
C language linkage. In particular, don't warn in

extern "C" {
  static NonPod foo();
}

Since getLanguageLinkage checks the language linkage, the linkage computation
cannot use the language linkage. Break the loop by checking just the context
in the linkage computation.

llvm-svn: 175117

1 files changed, 11 insertions, 0 deletions

diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index e1f40356e27..f675436fc5f 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -806,6 +806,17 @@ bool DeclContext::isExternCContext() const {
   return false;
 }
 
+bool DeclContext::isExternCXXContext() const {
+  const DeclContext *DC = this;
+  while (DC->DeclKind != Decl::TranslationUnit) {
+    if (DC->DeclKind == Decl::LinkageSpec)
+      return cast<LinkageSpecDecl>(DC)->getLanguage()
+        == LinkageSpecDecl::lang_cxx;
+    DC = DC->getParent();
+  }
+  return false;
+}
+
 bool DeclContext::Encloses(const DeclContext *DC) const {
   if (getPrimaryContext() != this)
     return getPrimaryContext()->Encloses(DC);