Add a missing check in CodeGen of packed classes with vtables. <rdar://problem/11324125>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155689 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGRecordLayoutBuilder.cpp

@@ -721,7 +721,13 @@ CGRecordLayoutBuilder::LayoutNonVirtualBases(const CXXRecordDecl *RD,
       llvm::FunctionType::get(llvm::Type::getInt32Ty(Types.getLLVMContext()),
                               /*isVarArg=*/true);
     llvm::Type *VTableTy = FunctionType->getPointerTo();
-    
+
+    if (getTypeAlignment(VTableTy) > Alignment) {
+      // FIXME: Should we allow this to happen in Sema?
+      assert(!Packed && "Alignment is wrong even with packed struct!");
+      return false;
+    }
+
     assert(NextFieldOffset.isZero() &&
            "VTable pointer must come first!");
     AppendField(CharUnits::Zero(), VTableTy->getPointerTo());

test/CodeGenCXX/class-layout.cpp

@@ -77,3 +77,17 @@ namespace Test6 {
   class E : public B {};
   E *e;
 }
+
+// <rdar://problem/11324125>: Make sure this doesn't crash.  (It's okay
+// if we start rejecting it at some point.)
+namespace Test7 {
+  #pragma pack (1)
+  class A {};
+  // CHECK: %"class.Test7::B" = type <{ i32 (...)**, %"class.Test7::A" }>
+  class B {
+     virtual ~B();
+     A a;
+  };
+  B* b;
+  #pragma pack ()
+}