From 800821a3b2b0e77436e9e3a5182bae80f728774d Mon Sep 17 00:00:00 2001
From: Fariborz Jahanian <fjahanian@apple.com>
Date: Wed, 12 Nov 2014 22:37:43 +0000
Subject: [PATCH] [Objective-C++ IRGen] do not generate .cxx_construct for
 class that contains trivially-constructible struct ivar. rdar://18950072

llvm-svn: 221823
---
 clang/lib/CodeGen/CodeGenModule.cpp              | 16 +++++++++++++++-
 .../test/CodeGenObjCXX/arc-cxx11-member-init.mm  | 13 +++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 17b0a4b62845..fe565523fd9c 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -3005,6 +3005,19 @@ static bool needsDestructMethod(ObjCImplementationDecl *impl) {
   return false;
 }
 
+static bool AllTrivialInitializers(CodeGenModule &CGM,
+                                   ObjCImplementationDecl *D) {
+  CodeGenFunction CGF(CGM);
+  for (ObjCImplementationDecl::init_iterator B = D->init_begin(),
+       E = D->init_end(); B != E; ++B) {
+    CXXCtorInitializer *CtorInitExp = *B;
+    Expr *Init = CtorInitExp->getInit();
+    if (!CGF.isTrivialInitializer(Init))
+      return false;
+  }
+  return true;
+}
+
 /// EmitObjCIvarInitializations - Emit information for ivar initialization
 /// for an implementation.
 void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) {
@@ -3025,7 +3038,8 @@ void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) {
 
   // If the implementation doesn't have any ivar initializers, we don't need
   // a .cxx_construct.
-  if (D->getNumIvarInitializers() == 0)
+  if (D->getNumIvarInitializers() == 0 ||
+      AllTrivialInitializers(*this, D))
     return;
   
   IdentifierInfo *II = &getContext().Idents.get(".cxx_construct");
diff --git a/clang/test/CodeGenObjCXX/arc-cxx11-member-init.mm b/clang/test/CodeGenObjCXX/arc-cxx11-member-init.mm
index 85fa5f49c0f7..9c673cfbebcd 100644
--- a/clang/test/CodeGenObjCXX/arc-cxx11-member-init.mm
+++ b/clang/test/CodeGenObjCXX/arc-cxx11-member-init.mm
@@ -30,3 +30,16 @@ class XClipboardDataSet
 // CHECK: [[THREE:%.*]] = bitcast i8* [[CALL]] to [[T:%.*]]*
 // CHECK: store [[T]]* [[THREE]], [[T]]** [[mClipData]], align 8
 
+// rdar://18950072
+struct Butt { };
+
+__attribute__((objc_root_class))
+@interface Foo {
+  Butt x;
+  Butt y;
+  Butt z;
+}
+@end
+@implementation Foo
+@end
+// CHECK-NOTE: define internal i8* @"\01-[Foo .cxx_construct