From 6dba4a1bc3c257bee0812a130c468917ea210e05 Mon Sep 17 00:00:00 2001
From: Eric Christopher <echristo@apple.com>
Date: Thu, 19 Jul 2012 22:22:51 +0000
Subject: [PATCH] Reset the layout of an ObjC class if we see an ivar in a
 category or implementation since we've now got a different layout.

Fixes rdar://11842763

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160526 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaDecl.cpp                    | 17 ++++++++++++
 test/CodeGenObjC/layout-bitfield-crash.m | 35 ++++++++++++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 test/CodeGenObjC/layout-bitfield-crash.m

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 4ea8df8b66..430ce9f7f7 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -9802,6 +9802,23 @@ void Sema::ActOnFields(Scope* S,
   if (EnclosingDecl->isInvalidDecl())
     return;
 
+  // If this is an Objective-C @implementation or category and we have
+  // new fields here we should reset the layout of the interface since
+  // it will now change.
+  if (!Fields.empty() && isa<ObjCContainerDecl>(EnclosingDecl)) {
+    ObjCContainerDecl *DC = cast<ObjCContainerDecl>(EnclosingDecl);
+    switch (DC->getKind()) {
+    default: break;
+    case Decl::ObjCCategory:
+      Context.ResetObjCLayout(cast<ObjCCategoryDecl>(DC)->getClassInterface());
+      break;
+    case Decl::ObjCImplementation:
+      Context.
+        ResetObjCLayout(cast<ObjCImplementationDecl>(DC)->getClassInterface());
+      break;
+    }
+  }
+  
   RecordDecl *Record = dyn_cast<RecordDecl>(EnclosingDecl);
 
   // Start counting up the number of named members; make sure to include
diff --git a/test/CodeGenObjC/layout-bitfield-crash.m b/test/CodeGenObjC/layout-bitfield-crash.m
new file mode 100644
index 0000000000..7e6e77ea7a
--- /dev/null
+++ b/test/CodeGenObjC/layout-bitfield-crash.m
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin11 -fobjc-runtime=macosx-10.7 -fobjc-gc -emit-llvm -g -o - %s
+// Check that this doesn't crash when compiled with debugging on.
+@class Foo;
+typedef struct Bar *BarRef;
+
+@interface Baz
+@end
+
+@interface Foo
+- (void) setFlag;
+@end
+
+@implementation Baz
+
+- (void) a:(BarRef)b
+{
+  Foo* view = (Foo*)self;
+  [view setFlag];
+}
+
+@end
+
+
+@implementation Foo
+{
+  int flag : 1;
+}
+
+- (void) setFlag
+{
+  if (!flag)
+    flag = 1;
+}
+
+@end
-- 
2.40.0