Support &__uuidof(type) as a non type template argument.

This idiom is used everywhere in MFC/COM code and as such this patch removes hundreds of errors when parsing MFC code with clang.

Example: 
template <class T, const GUID* g = &__uuidof(T)>
class ComTemplate  { };

typedef ComTemplate<struct_with_uuid, &__uuidof(struct_with_uuid)> COM_TYPE;

Of course this is just parsing support. Trying to use this in CodeGen will generate:
error: cannot yet mangle expression type CXXUuidofExpr

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@130381 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 16 insertions, 0 deletions

diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index 3deeedc90d..ae80181d84 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -3093,6 +3093,15 @@ CheckTemplateArgumentAddressOfObjectOrFunction(Sema &S,
   bool AddressTaken = false;
   SourceLocation AddrOpLoc;
   if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
+
+    // Support &__uuidof(class_with_uuid) as a non-type template argument.
+    // Very common in Microsoft COM headers.
+    if (S.getLangOptions().Microsoft && 
+      isa<CXXUuidofExpr>(UnOp->getSubExpr())) {
+      Converted = TemplateArgument(ArgIn);
+      return false;
+    }
+
     if (UnOp->getOpcode() == UO_AddrOf) {
       DRE = dyn_cast<DeclRefExpr>(UnOp->getSubExpr());
       AddressTaken = true;
diff --git a/test/Parser/MicrosoftExtensions.cpp b/test/Parser/MicrosoftExtensions.cpp
index a5d2d513b1..decd57510f 100644
--- a/test/Parser/MicrosoftExtensions.cpp
+++ b/test/Parser/MicrosoftExtensions.cpp
@@ -95,6 +95,13 @@ void template_uuid()
 }
 
 
+template <class T, const GUID* g = &__uuidof(T)>
+class COM_CLASS_TEMPLATE  { };
+
+typedef COM_CLASS_TEMPLATE<struct_with_uuid, &__uuidof(struct_with_uuid)> COM_TYPE_1;
+typedef COM_CLASS_TEMPLATE<struct_with_uuid> COM_TYPE_2;
+
+
 
 class CtorCall { 
 public: