MS ABI: Mark direct virtual bases as visted when building vtable paths

Fixes PR19240.  In retrospect, this is a fairly obvious bug.  :)

llvm-svn: 204744

2 files changed, 25 insertions, 0 deletions

diff --git a/clang/lib/AST/VTableBuilder.cpp b/clang/lib/AST/VTableBuilder.cpp
index 12c5b8f6879..eef91f7416e 100644
--- a/clang/lib/AST/VTableBuilder.cpp
+++ b/clang/lib/AST/VTableBuilder.cpp
@@ -3210,6 +3210,8 @@ void MicrosoftVTableContext::computeVTablePaths(bool ForVBTables,
     // morally virtual bases.
     for (const auto &I : Base->vbases())
       VBasesSeen.insert(I.getType()->getAsCXXRecordDecl());
+    if (I.isVirtual())
+      VBasesSeen.insert(Base);
   }
 
   // Sort the paths into buckets, and if any of them are ambiguous, extend all
diff --git a/clang/test/CodeGenCXX/microsoft-abi-vtables-virtual-inheritance.cpp b/clang/test/CodeGenCXX/microsoft-abi-vtables-virtual-inheritance.cpp
index 2788965d46a..634f583e735 100644
--- a/clang/test/CodeGenCXX/microsoft-abi-vtables-virtual-inheritance.cpp
+++ b/clang/test/CodeGenCXX/microsoft-abi-vtables-virtual-inheritance.cpp
@@ -659,3 +659,26 @@ C c;
 // MANGLING-DAG: @"\01??_7C@pr17748@@6BA@1@@"
 // MANGLING-DAG: @"\01??_7C@pr17748@@6BB@1@@"
 }
+
+namespace pr19240 {
+struct A {
+  virtual void c();
+};
+
+struct B : virtual A {
+  virtual void c();
+};
+
+struct C { };
+
+struct D : virtual A, virtual C, B {};
+
+D obj;
+
+// Each MDC only has one vftable.
+
+// MANGLING-DAG: @"\01??_7D@pr19240@@6B@"
+// MANGLING-DAG: @"\01??_7A@pr19240@@6B@"
+// MANGLING-DAG: @"\01??_7B@pr19240@@6B@"
+
+}