[MS ABI, DebugInfo] Omit the size for model-less pointers-to-members

The representation of a pointer-to-member in the MS ABI is governed by
the layout of the relevant class or if a model has been explicitly
specified.  If no model is specified, then an appropriate
"worst-case-scenario" model is implicitly chosen if, and only, if the
pointer-to-member type's representation was needed.

Debug info cannot force a pointer-to-member type to have a
representation so do not try to query the size of such a type unless we
know it is safe to do so.

llvm-svn: 238259

1 files changed, 5 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index be684d46cb7..48458dbd600 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1878,11 +1878,13 @@ llvm::DIType *CGDebugInfo::CreateType(const RValueReferenceType *Ty,
 
 llvm::DIType *CGDebugInfo::CreateType(const MemberPointerType *Ty,
                                       llvm::DIFile *U) {
+  uint64_t Size = CGM.getCXXABI().isTypeInfoCalculable(QualType(Ty, 0))
+                      ? CGM.getContext().getTypeSize(Ty)
+                      : 0;
   llvm::DIType *ClassType = getOrCreateType(QualType(Ty->getClass(), 0), U);
   if (Ty->isMemberDataPointerType())
     return DBuilder.createMemberPointerType(
-      getOrCreateType(Ty->getPointeeType(), U), ClassType,
-      CGM.getContext().getTypeSize(Ty));
+        getOrCreateType(Ty->getPointeeType(), U), ClassType, Size);
 
   const FunctionProtoType *FPT =
       Ty->getPointeeType()->getAs<FunctionProtoType>();
@@ -1890,7 +1892,7 @@ llvm::DIType *CGDebugInfo::CreateType(const MemberPointerType *Ty,
       getOrCreateInstanceMethodType(CGM.getContext().getPointerType(QualType(
                                         Ty->getClass(), FPT->getTypeQuals())),
                                     FPT, U),
-      ClassType, CGM.getContext().getTypeSize(Ty));
+      ClassType, Size);
 }
 
 llvm::DIType *CGDebugInfo::CreateType(const AtomicType *Ty, llvm::DIFile *U) {