The result of the Microsoft __uuidof operator must be considered a global lvalue during constant expression evaluation.

Otherwise we would get this error in C++11 mode (because of a recent change):
   error: non-type template argument of type 'const _GUID *' is not a constant expression

For code like:
template <const GUID* g = &__uuidof(struct_with_uuid)>
class COM_CLASS { };

llvm-svn: 154790

Author: fpichet

clang/lib/AST/ExprConstant.cpp

@@ -934,6 +934,7 @@ static bool IsGlobalLValue(APValue::LValueBase B) {
   case Expr::ObjCStringLiteralClass:
   case Expr::ObjCEncodeExprClass:
   case Expr::CXXTypeidExprClass:
+  case Expr::CXXUuidofExprClass:
     return true;
   case Expr::CallExprClass:
     return IsStringLiteralCall(cast<CallExpr>(E));
@@ -2872,6 +2873,7 @@ class LValueExprEvaluator
   bool VisitStringLiteral(const StringLiteral *E) { return Success(E); }
   bool VisitObjCEncodeExpr(const ObjCEncodeExpr *E) { return Success(E); }
   bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
+  bool VisitCXXUuidofExpr(const CXXUuidofExpr *E);
   bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
   bool VisitUnaryDeref(const UnaryOperator *E);
   bool VisitUnaryReal(const UnaryOperator *E);
@@ -2977,6 +2979,10 @@ bool LValueExprEvaluator::VisitCXXTypeidExpr(const CXXTypeidExpr *E) {
   return Success(E);
 }
 
+bool LValueExprEvaluator::VisitCXXUuidofExpr(const CXXUuidofExpr *E) {
+  return Success(E);
+} 
+
 bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
   // Handle static data members.
   if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) {

clang/test/Parser/MicrosoftExtensions.cpp

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -fsyntax-only -Wno-unused-value -Wmicrosoft -verify -fms-extensions -fdelayed-template-parsing
+// RUN: %clang_cc1 %s -std=c++11 -fsyntax-only -Wno-unused-value -Wmicrosoft -verify -fms-extensions -fdelayed-template-parsing
 
 /* Microsoft attribute tests */
 [repeatable][source_annotation_attribute( Parameter|ReturnValue )]
@@ -103,7 +103,7 @@ typedef COM_CLASS_TEMPLATE<struct_with_uuid> COM_TYPE_2;
 
 template <class T, const GUID& g>
 class COM_CLASS_TEMPLATE_REF  { };
-typedef COM_CLASS_TEMPLATE<struct_with_uuid, __uuidof(struct_with_uuid)> COM_TYPE_REF;
+typedef COM_CLASS_TEMPLATE_REF<struct_with_uuid, __uuidof(struct_with_uuid)> COM_TYPE_REF;
 
   struct late_defined_uuid;
   template<typename T>