[PATCH] CodeGen: __uuidof should work even with an incomplete _GUID type

[Reid Kleckner]

================
Comment at: test/CodeGenCXX/microsoft-uuidof.cpp:8
@@ +7,3 @@
+#ifdef WRONG_GUID
+    unsigned int SomethingWentWrong[4];
+#else
----------------
I was expecting a diagnostic.  :)

Previously clang would reject this code:
struct __declspec(uuid("12345678-1234-1234-1234-1234567890aB")) S { };
typedef struct _GUID { int x; int y; } GUID;
GUID g = __uuidof(S);

cl.exe accepts and only copies the first 8 bytes, but I'd like to preserve the original clang behavior.  Can we at least check that the sizeof() the user's type is 16?


http://llvm-reviews.chandlerc.com/D1375