From 0e84602d5cb324f8b3b0b540347220901e8761be Mon Sep 17 00:00:00 2001
From: Eli Friedman <eli.friedman@gmail.com>
Date: Fri, 26 Oct 2012 22:38:05 +0000
Subject: [PATCH] Don't crash synthesizing an ObjC property with an empty
 struct type.  <rdar://problem/12547611>.

llvm-svn: 166825
---
 clang/lib/CodeGen/CGObjC.cpp                       |  8 ++++++++
 clang/test/CodeGenObjC/atomic-aggregate-property.m | 11 +++++++++++
 2 files changed, 19 insertions(+)

diff --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index a47c56f67c7a..c90e4eca8476 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -810,6 +810,10 @@ CodeGenFunction::generateObjCGetterBody(const ObjCImplementationDecl *classImpl,
   PropertyImplStrategy strategy(CGM, propImpl);
   switch (strategy.getKind()) {
   case PropertyImplStrategy::Native: {
+    // We don't need to do anything for a zero-size struct.
+    if (strategy.getIvarSize().isZero())
+      return;
+
     LValue LV = EmitLValueForIvar(TypeOfSelfObject(), LoadObjCSelf(), ivar, 0);
 
     // Currently, all atomic accesses have to be through integer
@@ -1068,6 +1072,10 @@ CodeGenFunction::generateObjCSetterBody(const ObjCImplementationDecl *classImpl,
   PropertyImplStrategy strategy(CGM, propImpl);
   switch (strategy.getKind()) {
   case PropertyImplStrategy::Native: {
+    // We don't need to do anything for a zero-size struct.
+    if (strategy.getIvarSize().isZero())
+      return;
+
     llvm::Value *argAddr = LocalDeclMap[*setterMethod->param_begin()];
 
     LValue ivarLValue =
diff --git a/clang/test/CodeGenObjC/atomic-aggregate-property.m b/clang/test/CodeGenObjC/atomic-aggregate-property.m
index 978299b45a6d..878255b0fb3f 100644
--- a/clang/test/CodeGenObjC/atomic-aggregate-property.m
+++ b/clang/test/CodeGenObjC/atomic-aggregate-property.m
@@ -1,6 +1,7 @@
 // RUN: %clang_cc1 -triple x86_64-apple-darwin10  -fobjc-gc -emit-llvm -o - %s | FileCheck -check-prefix LP64 %s
 // RUN: %clang_cc1 -x objective-c++ -triple x86_64-apple-darwin10  -fobjc-gc -emit-llvm -o - %s | FileCheck -check-prefix LP64 %s
 // rdar: // 7849824
+// <rdar://problem/12547611>
 
 struct s {
   double a, b, c, d;  
@@ -12,16 +13,20 @@ struct s1 {
     id k;
 };
 
+struct s2 {};
+
 @interface A 
 @property (readwrite) double x;
 @property (readwrite) struct s y;
 @property (nonatomic, readwrite) struct s1 z;
+@property (readwrite) struct s2 a;
 @end
 
 @implementation A
 @synthesize x;
 @synthesize y;
 @synthesize z;
+@synthesize a;
 @end
 // CHECK-LP64: define internal double @"\01-[A x]"(
 // CHECK-LP64: load atomic i64* {{%.*}} unordered, align 8
@@ -40,3 +45,9 @@ struct s1 {
 
 // CHECK-LP64: define internal void @"\01-[A setZ:]"(
 // CHECK-LP64: call i8* @objc_memmove_collectable(
+
+// CHECK-LP64: define internal void @"\01-[A a]"(
+// (do nothing)
+
+// CHECK-LP64: define internal void @"\01-[A setA:]"(
+// (do nothing)