Index: lit/SymbolFile/NativePDB/Inputs/tag-types.lldbinit
===================================================================
--- lit/SymbolFile/NativePDB/Inputs/tag-types.lldbinit
+++ lit/SymbolFile/NativePDB/Inputs/tag-types.lldbinit
@@ -3,6 +3,8 @@
 type lookup -- Union
 type lookup -- Derived
 type lookup -- Derived2
+type lookup -- DerivedVirtual1
+type lookup -- DerivedVirtual2
 type lookup -- EnumInt
 type lookup -- EnumShort
 type lookup -- InvalidType
Index: lit/SymbolFile/NativePDB/tag-types.cpp
===================================================================
--- lit/SymbolFile/NativePDB/tag-types.cpp
+++ lit/SymbolFile/NativePDB/tag-types.cpp
@@ -115,6 +115,12 @@
 
 unsigned Derived2::StaticDataMember = 0;
 
+// Test virtual inheritance.
+class DerivedVirtual1 : public virtual Class {};
+
+// Test the correctness of the virtual bases order.
+class DerivedVirtual2 : public DerivedVirtual1, public virtual OneMember {};
+
 // Test scoped enums and unscoped enums.
 enum class EnumInt {
   A = 1,
@@ -133,6 +139,8 @@
   Union U;
   Derived D;
   Derived2 D2;
+  DerivedVirtual1 DV1;
+  DerivedVirtual2 DV2;
   EnumInt EI;
   EnumShort ES;
   
@@ -221,6 +229,12 @@
 // CHECK-NEXT: class Derived2 : protected Class, private Struct {
 // CHECK-NEXT:     static unsigned int StaticDataMember;
 // CHECK-NEXT: }
+// CHECK-NEXT: (lldb) type lookup -- DerivedVirtual1
+// CHECK-NEXT: class DerivedVirtual1 : virtual public Class {
+// CHECK-NEXT: }
+// CHECK-NEXT: (lldb) type lookup -- DerivedVirtual2
+// CHECK-NEXT: class DerivedVirtual2 : public DerivedVirtual1, virtual public Class, virtual public OneMember {
+// CHECK-NEXT: }
 // CHECK-NEXT: (lldb) type lookup -- EnumInt
 // CHECK-NEXT: enum EnumInt {
 // CHECK-NEXT:     A,
Index: source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.h
===================================================================
--- source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.h
+++ source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.h
@@ -49,6 +49,7 @@
   PdbAstBuilder &m_ast_builder;
   llvm::pdb::TpiStream &m_tpi;
   std::vector<std::unique_ptr<clang::CXXBaseSpecifier>> m_bases;
+  std::map<uint64_t, std::unique_ptr<clang::CXXBaseSpecifier>> m_vbases;
   ClangASTImporter::LayoutInfo m_layout;
 
 public:
@@ -66,7 +67,9 @@
 
 private:
   clang::QualType AddBaseClassForTypeIndex(llvm::codeview::TypeIndex ti,
-                                           llvm::codeview::MemberAccess access);
+                                           llvm::codeview::MemberAccess access,
+                                           bool is_virtual,
+                                           uint64_t vtable_idx);
 };
 
 } // namespace npdb
Index: source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp
===================================================================
--- source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp
+++ source/Plugins/SymbolFile/NativePDB/UdtRecordCompleter.cpp
@@ -50,7 +50,8 @@
 }
 
 clang::QualType UdtRecordCompleter::AddBaseClassForTypeIndex(
-    llvm::codeview::TypeIndex ti, llvm::codeview::MemberAccess access) {
+    llvm::codeview::TypeIndex ti, llvm::codeview::MemberAccess access,
+    bool is_virtual, uint64_t vtable_idx) {
   PdbTypeSymId type_id(ti);
   clang::QualType qt = m_ast_builder.GetOrCreateType(type_id);
 
@@ -58,17 +59,24 @@
 
   std::unique_ptr<clang::CXXBaseSpecifier> base_spec =
       m_ast_builder.clang().CreateBaseClassSpecifier(
-          qt.getAsOpaquePtr(), TranslateMemberAccess(access), false,
+          qt.getAsOpaquePtr(), TranslateMemberAccess(access), is_virtual,
           udt_cvt.kind() == LF_CLASS);
   lldbassert(base_spec);
-  m_bases.push_back(std::move(base_spec));
+
+  // Process virtual bases separately because their order in the result vector
+  // must correspond to the indexes in the vbtable.
+  if (is_virtual)
+    m_vbases[vtable_idx] = std::move(base_spec);
+  else
+    m_bases.push_back(std::move(base_spec));
+
   return qt;
 }
 
 Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
                                            BaseClassRecord &base) {
   clang::QualType base_qt =
-      AddBaseClassForTypeIndex(base.Type, base.getAccess());
+      AddBaseClassForTypeIndex(base.Type, base.getAccess(), false, 0);
 
   auto decl =
       m_ast_builder.clang().GetAsCXXRecordDecl(base_qt.getAsOpaquePtr());
@@ -82,9 +90,9 @@
 
 Error UdtRecordCompleter::visitKnownMember(CVMemberRecord &cvr,
                                            VirtualBaseClassRecord &base) {
-  AddBaseClassForTypeIndex(base.BaseType, base.getAccess());
+  AddBaseClassForTypeIndex(base.BaseType, base.getAccess(), true,
+                           base.VTableIndex);
 
-  // FIXME: Handle virtual base offsets.
   return Error::success();
 }
 
@@ -177,6 +185,10 @@
 }
 
 void UdtRecordCompleter::complete() {
+  // Flush all virtual bases using the correct order.
+  for (auto &pair : m_vbases)
+    m_bases.push_back(std::move(pair.second));
+
   ClangASTContext &clang = m_ast_builder.clang();
   clang.TransferBaseClasses(m_derived_ct.GetOpaqueQualType(),
                             std::move(m_bases));