Add first pieces of support for parsing and representing 
extern "C" in C++ mode.  Patch by Mike Stump!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@45904 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CodeGen/CodeGenModule.cpp b/CodeGen/CodeGenModule.cpp
index 9a65d2e..bb61dc7 100644
--- a/CodeGen/CodeGenModule.cpp
+++ b/CodeGen/CodeGenModule.cpp
@@ -44,6 +44,16 @@
                     &Msg, 1, &Range, 1);
 }
 
+/// WarnUnsupported - Print out a warning that codegen doesn't support the
+/// specified decl yet.
+void CodeGenModule::WarnUnsupported(const Decl *D, const char *Type) {
+  unsigned DiagID = getDiags().getCustomDiagID(Diagnostic::Warning, 
+                                               "cannot codegen this %0 yet");
+  std::string Msg = Type;
+  getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID,
+                    &Msg, 1);
+}
+
 /// ReplaceMapValuesWith - This is a really slow and bad function that
 /// searches for any entries in GlobalDeclMap that point to OldVal, changing
 /// them to point to NewVal.  This is badbadbad, FIXME!