[clang][Interp] Fix virtual calls with reference instance pointers

getCXXRecordType() on those types does not return the type we need.
Use getPointeeCXXRecordType() instead in those cases.

Author: tbaederr

clang/lib/AST/Interp/Interp.h

@@ -2074,8 +2074,12 @@ inline bool CallVirt(InterpState &S, CodePtr OpPC, const Function *Func,
   size_t ThisOffset = ArgSize - (Func->hasRVO() ? primSize(PT_Ptr) : 0);
   Pointer &ThisPtr = S.Stk.peek<Pointer>(ThisOffset);
 
-  const CXXRecordDecl *DynamicDecl =
-      ThisPtr.getDeclDesc()->getType()->getAsCXXRecordDecl();
+  QualType DynamicType = ThisPtr.getDeclDesc()->getType();
+  const CXXRecordDecl *DynamicDecl;
+  if (DynamicType->isPointerType() || DynamicType->isReferenceType())
+    DynamicDecl = DynamicType->getPointeeCXXRecordDecl();
+  else
+    DynamicDecl = ThisPtr.getDeclDesc()->getType()->getAsCXXRecordDecl();
   const auto *StaticDecl = cast<CXXRecordDecl>(Func->getParentDecl());
   const auto *InitialFunction = cast<CXXMethodDecl>(Func->getDecl());
   const CXXMethodDecl *Overrider = S.getContext().getOverridingFunction(

clang/test/SemaCXX/undefined-internal.cpp

@@ -2,11 +2,21 @@
 // RUN: %clang_cc1 -fsyntax-only -verify -Wbind-to-temporary-copy -std=c++98 %s
 // RUN: %clang_cc1 -fsyntax-only -verify -Wbind-to-temporary-copy -std=c++11 %s
 
+// RUN: %clang_cc1 -fsyntax-only -verify -Wbind-to-temporary-copy %s -fexperimental-new-constant-interpreter
+// RUN: %clang_cc1 -fsyntax-only -verify -Wbind-to-temporary-copy -std=c++98 %s -fexperimental-new-constant-interpreter
+// RUN: %clang_cc1 -fsyntax-only -verify -Wbind-to-temporary-copy -std=c++11 %s -fexperimental-new-constant-interpreter
+
+
 // Make sure we don't produce invalid IR.
 // RUN: %clang_cc1 -emit-llvm-only %s
 // RUN: %clang_cc1 -emit-llvm-only -std=c++98 %s
 // RUN: %clang_cc1 -emit-llvm-only -std=c++11 %s
 
+// RUN: %clang_cc1 -emit-llvm-only %s -fexperimental-new-constant-interpreter
+// RUN: %clang_cc1 -emit-llvm-only -std=c++98 %s -fexperimental-new-constant-interpreter
+// RUN: %clang_cc1 -emit-llvm-only -std=c++11 %s -fexperimental-new-constant-interpreter
+
+
 namespace test1 {
   static void foo(); // expected-warning {{function 'test1::foo' has internal linkage but is not defined}}
   template <class T> static void bar(); // expected-warning {{function 'test1::bar<int>' has internal linkage but is not defined}}