2 files changed, 28 insertions, 11 deletions

diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp b/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp
index 37be3bc9cdf..ba5c14b9603 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp
@@ -50,7 +50,8 @@ UdtRecordCompleter::UdtRecordCompleter(PdbTypeSymId id,
 }
 
 clang::QualType UdtRecordCompleter::AddBaseClassForTypeIndex(
-    llvm::codeview::TypeIndex ti, llvm::codeview::MemberAccess access) {
+    llvm::codeview::TypeIndex ti, llvm::codeview::MemberAccess access,
+    llvm::Optional<uint64_t> vtable_idx) {
   PdbTypeSymId type_id(ti);
   clang::QualType qt = m_ast_builder.GetOrCreateType(type_id);
 
@@ -58,10 +59,13 @@ clang::QualType UdtRecordCompleter::AddBaseClassForTypeIndex(
 
   std::unique_ptr<clang::CXXBaseSpecifier> base_spec =
       m_ast_builder.clang().CreateBaseClassSpecifier(
-          qt.getAsOpaquePtr(), TranslateMemberAccess(access), false,
-          udt_cvt.kind() == LF_CLASS);
+          qt.getAsOpaquePtr(), TranslateMemberAccess(access),
+          vtable_idx.hasValue(), udt_cvt.kind() == LF_CLASS);
   lldbassert(base_spec);
-  m_bases.push_back(std::move(base_spec));
+
+  m_bases.push_back(
+      std::make_pair(vtable_idx.getValueOr(0), std::move(base_spec)));
+
   return qt;
 }
 
@@ -98,9 +102,8 @@ Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
 
 Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
                                            VirtualBaseClassRecord &base) {
-  AddBaseClassForTypeIndex(base.BaseType, base.getAccess());
+  AddBaseClassForTypeIndex(base.BaseType, base.getAccess(), base.VTableIndex);
 
-  // FIXME: Handle virtual base offsets.
   return Error::success();
 }
 
@@ -209,9 +212,19 @@ Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
 }
 
 void UdtRecordCompleter::complete() {
+  // Ensure the correct order for virtual bases.
+  std::stable_sort(m_bases.begin(), m_bases.end(),
+                   [](const IndexedBase &lhs, const IndexedBase &rhs) {
+                     return lhs.first < rhs.first;
+                   });
+
+  std::vector<std::unique_ptr<clang::CXXBaseSpecifier>> bases;
+  bases.reserve(m_bases.size());
+  for (auto &ib : m_bases)
+    bases.push_back(std::move(ib.second));
+
   ClangASTContext &clang = m_ast_builder.clang();
-  clang.TransferBaseClasses(m_derived_ct.GetOpaqueQualType(),
-                            std::move(m_bases));
+  clang.TransferBaseClasses(m_derived_ct.GetOpaqueQualType(), std::move(bases));
 
   clang.AddMethodOverridesForCXXRecordType(m_derived_ct.GetOpaqueQualType());
   ClangASTContext::BuildIndirectFields(m_derived_ct);
diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.h b/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.h
index 43015f9e25b..b11e813c122 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.h
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.h
@@ -35,6 +35,9 @@ namespace npdb {
 class PdbAstBuilder;
 
 class UdtRecordCompleter : public llvm::codeview::TypeVisitorCallbacks {
+  using IndexedBase =
+      std::pair<uint64_t, std::unique_ptr<clang::CXXBaseSpecifier>>;
+
   union UdtTagRecord {
     UdtTagRecord() {}
     llvm::codeview::UnionRecord ur;
@@ -47,7 +50,7 @@ class UdtRecordCompleter : public llvm::codeview::TypeVisitorCallbacks {
   clang::TagDecl &m_tag_decl;
   PdbAstBuilder &m_ast_builder;
   llvm::pdb::TpiStream &m_tpi;
-  std::vector<std::unique_ptr<clang::CXXBaseSpecifier>> m_bases;
+  std::vector<IndexedBase> m_bases;
   ClangASTImporter::LayoutInfo m_layout;
 
 public:
@@ -64,8 +67,9 @@ public:
   void complete();
 
 private:
-  clang::QualType AddBaseClassForTypeIndex(llvm::codeview::TypeIndex ti,
-                                           llvm::codeview::MemberAccess access);
+  clang::QualType AddBaseClassForTypeIndex(
+      llvm::codeview::TypeIndex ti, llvm::codeview::MemberAccess access,
+      llvm::Optional<uint64_t> vtable_idx = llvm::Optional<uint64_t>());
   void AddMethod(llvm::StringRef name, llvm::codeview::TypeIndex type_idx,
                  llvm::codeview::MemberAccess access,
                  llvm::codeview::MethodOptions options,