From f96bdf409fc9e5570e35aaf8a9167265e63d58d8 Mon Sep 17 00:00:00 2001
From: Fariborz Jahanian <fjahanian@apple.com>
Date: Mon, 3 Jan 2011 19:23:18 +0000
Subject: [PATCH] Consider zero-length array of structs when computing ivar
 layouts for objc-gc. Fixes // rdar://8800513

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@122762 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CGObjCMac.cpp                    |  2 +-
 test/CodeGenObjC/ivar-layout-array0-struct.m | 22 ++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 test/CodeGenObjC/ivar-layout-array0-struct.m

diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 66913c8ee2..2a27e91925 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -3681,7 +3681,7 @@ void CGObjCCommonMac::BuildAggrIvarLayout(const ObjCImplementationDecl *OI,
 
       assert(!FQT->isUnionType() &&
              "layout for array of unions not supported");
-      if (FQT->isRecordType()) {
+      if (FQT->isRecordType() && ElCount) {
         int OldIndex = IvarsInfo.size() - 1;
         int OldSkIndex = SkipIvars.size() -1;
 
diff --git a/test/CodeGenObjC/ivar-layout-array0-struct.m b/test/CodeGenObjC/ivar-layout-array0-struct.m
new file mode 100644
index 0000000000..4300db3641
--- /dev/null
+++ b/test/CodeGenObjC/ivar-layout-array0-struct.m
@@ -0,0 +1,22 @@
+// RUN: %clang_cc1 -fobjc-gc -triple x86_64-apple-darwin -O0 -S %s -o %t-64.s
+// RUN: FileCheck -check-prefix LP64 --input-file=%t-64.s %s
+
+// rdar://8800513
+@interface NSObject {
+  id isa;
+}
+@end
+
+typedef struct {
+    id b;
+} st;
+
+@interface Test : NSObject {
+    int a;
+    st b[0];
+}
+@end
+
+@implementation Test @end
+// CHECK-LP64: L_OBJC_CLASS_NAME_4:
+// CHECK-LP64-NEXT: .asciz      "\001\020"
-- 
2.50.1