[MS ABI] Add testcase which was missing from r236354

This test verifies that we can detect when the inheritance paths are
ambiguous due to covariant thunks, ensuring we don't regress PR16759.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@236381 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/CodeGenCXX/microsoft-abi-vtables-ambiguous.cpp b/test/CodeGenCXX/microsoft-abi-vtables-ambiguous.cpp
new file mode 100644 (file)
index 0000000..c05fc17
--- /dev/null
+++ b/test/CodeGenCXX/microsoft-abi-vtables-ambiguous.cpp
@@ -0,0 +1,44 @@
+// RUN: %clang_cc1 %s -emit-llvm-only -triple=i386-pc-win32 -verify -DTEST1
+// RUN: %clang_cc1 %s -emit-llvm-only -triple=i386-pc-win32 -verify -DTEST2
+
+#ifdef TEST1
+struct A {
+  virtual A *foo();  // in vftable slot #0.
+  virtual A *bar();  // in vftable slot #1.
+};
+
+struct B : virtual A {
+  // appended to the A subobject's vftable in slot #2.
+  virtual B *foo(); // expected-note{{covariant thunk required by 'foo'}}
+};
+
+struct C : virtual A {
+  // appended to the A subobject's vftable in slot #2.
+  virtual C *bar(); // expected-note{{covariant thunk required by 'bar'}}
+};
+
+struct D : B, C { D(); }; // expected-error{{ambiguous vftable component}}
+D::D() {}
+#endif
+
+#ifdef TEST2
+struct A {
+  virtual A *foo(); // in vftable slot #0
+};
+
+struct B : virtual A {
+  // appended to the A subobject's vftable in slot #1.
+  virtual B *foo(); // expected-note{{covariant thunk required by 'foo'}}
+};
+
+struct C : virtual A {
+  // appended to the A subobject's vftable in slot #1.
+  virtual C *foo(); // expected-note{{covariant thunk required by 'foo'}}
+};
+
+struct D : B, C { // expected-error{{ambiguous vftable component}}
+  virtual D *foo();
+  D();
+};
+D::D() {}
+#endif