[PATCH] D20843: ObjC lifetime: pull sugar off when the qualifiers conflict.

Manman Ren via cfe-commits cfe-commits at lists.llvm.org
Tue May 31 16:39:45 PDT 2016


manmanren created this revision.
manmanren added a reviewer: rjmccall.
manmanren added a subscriber: cfe-commits.

It's possible to have multiple local ObjCLifetime qualifiers. When there is
a conflict, we can't stop after we reach a type that is directly qualified.
We need to keep pulling sugar off and removing the ObjCLifetime qualifers.

One example:
@implementation A
- init {
  __attribute__((objc_ownership(strong))) __typeof__(self) self_strong;
  __attribute__((objc_ownership(weak))) __typeof__(self_strong) self_weak;
}
@end



http://reviews.llvm.org/D20843

Files:
  lib/Sema/SemaType.cpp
  test/SemaObjC/arc-objc-lifetime-conflict.m

Index: test/SemaObjC/arc-objc-lifetime-conflict.m
===================================================================
--- test/SemaObjC/arc-objc-lifetime-conflict.m
+++ test/SemaObjC/arc-objc-lifetime-conflict.m
@@ -0,0 +1,32 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin11 -fobjc-arc -fobjc-runtime-has-weak %s -emit-llvm -o - | FileCheck %s
+
+// CHECK: bitcast {{.*}} %self_weak_s_w_s
+// CHECK-NEXT: objc_destroyWeak
+// CHECK-NEXT: bitcast {{.*}} %self_strong_w_s
+// CHECK-NEXT: objc_storeStrong
+// CHECK-NEXT: bitcast {{.*}} %self_weak_s
+// CHECK-NEXT: objc_destroyWeak
+// CHECK-NEXT: bitcast {{.*}} %self_weak_s3
+// CHECK-NEXT: objc_destroyWeak
+// CHECK-NEXT: bitcast {{.*}} %self_strong3
+// CHECK-NEXT: objc_storeStrong
+// CHECK-NEXT: bitcast {{.*}} %self_strong2
+// CHECK-NEXT: objc_storeStrong
+// CHECK-NEXT: bitcast {{.*}} %self_strong
+// CHECK-NEXT: objc_storeStrong
+ at interface NSObject
+ at end
+ at interface A : NSObject
+ at end
+ at implementation A
+- (void)test {
+  __attribute__((objc_ownership(strong))) __typeof__(self) self_strong;
+  __attribute__((objc_ownership(strong))) __typeof__(self_strong) self_strong2;
+  __attribute__((objc_ownership(strong))) __typeof__(self_strong2) self_strong3;
+  __attribute__((objc_ownership(weak))) __typeof__(self_strong3) self_weak_s3;
+ 
+  __attribute__((objc_ownership(weak))) __typeof__(self_strong) self_weak_s;
+  __attribute__((objc_ownership(strong))) __typeof__(self_weak_s) self_strong_w_s;
+  __attribute__((objc_ownership(weak))) __typeof__(self_strong_w_s) self_weak_s_w_s;
+}
+ at end
Index: lib/Sema/SemaType.cpp
===================================================================
--- lib/Sema/SemaType.cpp
+++ lib/Sema/SemaType.cpp
@@ -5415,11 +5415,13 @@
     }
 
     // Otherwise, if the qualifiers actually conflict, pull sugar off
-    // until we reach a type that is directly qualified.
+    // and remove the ObjCLifetime qualifiers.
     if (previousLifetime != lifetime) {
-      // This should always terminate: the canonical type is
-      // qualified, so some bit of sugar must be hiding it.
-      while (!underlyingType.Quals.hasObjCLifetime()) {
+      // It's possible to have multiple local ObjCLifetime qualifiers. We
+      // can't stop after we reach a type that is directly qualified.
+      const Type *prevTy = nullptr;
+      while (!prevTy || prevTy != underlyingType.Ty) {
+        prevTy = underlyingType.Ty;
         underlyingType = underlyingType.getSingleStepDesugaredType();
       }
       underlyingType.Quals.removeObjCLifetime();


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D20843.59149.patch
Type: text/x-patch
Size: 2550 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20160531/79307150/attachment.bin>


More information about the cfe-commits mailing list