Tighten up the rules for precise lifetime and document

the requirements on the ARC optimizer.

rdar://13407451

llvm-svn: 176924

2 files changed, 121 insertions, 72 deletions

diff --git a/clang/test/CodeGenObjC/arc-precise-lifetime.m b/clang/test/CodeGenObjC/arc-precise-lifetime.m
new file mode 100644
index 00000000000..595a4f9fdf2
--- /dev/null
+++ b/clang/test/CodeGenObjC/arc-precise-lifetime.m
@@ -0,0 +1,120 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -fblocks -fobjc-arc -fobjc-runtime-has-weak -O2 -disable-llvm-optzns -o - %s | FileCheck %s
+
+#define PRECISE_LIFETIME __attribute__((objc_precise_lifetime))
+
+id test0_helper(void) __attribute__((ns_returns_retained));
+void test0() {
+  PRECISE_LIFETIME id x = test0_helper();
+  x = 0;
+  // CHECK:      [[X:%.*]] = alloca i8*
+  // CHECK-NEXT: [[CALL:%.*]] = call i8* @test0_helper()
+  // CHECK-NEXT: store i8* [[CALL]], i8** [[X]]
+
+  // CHECK-NEXT: [[T1:%.*]] = load i8** [[X]]
+  // CHECK-NEXT: store i8* null, i8** [[X]]
+  // CHECK-NEXT: call void @objc_release(i8* [[T1]]) [[NUW:#[0-9]+]]
+  // CHECK-NOT:  clang.imprecise_release
+
+  // CHECK-NEXT: [[T1:%.*]] = load i8** [[X]]
+  // CHECK-NEXT: call void @objc_release(i8* [[T1]]) [[NUW:#[0-9]+]]
+  // CHECK-NOT:  clang.imprecise_release
+
+  // CHECK-NEXT: ret void
+}
+
+// rdar://problem/9821110
+@interface Test1
+- (char*) interior __attribute__((objc_returns_inner_pointer));
+// Should we allow this on properties?
+@end
+extern Test1 *test1_helper(void);
+
+// CHECK: define void @test1a()
+void test1a(void) {
+  // CHECK:      [[T0:%.*]] = call [[TEST1:%.*]]* @test1_helper()
+  // CHECK-NEXT: [[T1:%.*]] = bitcast [[TEST1]]* [[T0]] to i8*
+  // CHECK-NEXT: [[T2:%.*]] = call i8* @objc_retainAutoreleasedReturnValue(i8* [[T1]])
+  // CHECK-NEXT: [[T3:%.*]] = bitcast i8* [[T2]] to [[TEST1]]*
+  // CHECK-NEXT: store [[TEST1]]* [[T3]]
+  // CHECK-NEXT: [[T0:%.*]] = load [[TEST1]]**
+  // CHECK-NEXT: [[T1:%.*]] = bitcast [[TEST1]]* [[T0]] to i8*
+  // CHECK-NEXT: [[T2:%.*]] = call i8* @objc_retainAutorelease(i8* [[T1]])
+  // CHECK-NEXT: [[T3:%.*]] = bitcast i8* [[T2]] to [[TEST1]]*
+  // CHECK-NEXT: [[T4:%.*]] = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_
+  // CHECK-NEXT: [[T5:%.*]] = bitcast [[TEST1]]* [[T3]] to i8*
+  // CHECK-NEXT: [[T6:%.*]] = call i8* bitcast
+  // CHECK-NEXT: store i8* [[T6]], i8**
+  // CHECK-NEXT: [[T0:%.*]] = load [[TEST1]]**
+  // CHECK-NEXT: [[T1:%.*]] = bitcast [[TEST1]]* [[T0]] to i8*
+  // CHECK-NEXT: call void @objc_release(i8* [[T1]]) [[NUW]], !clang.imprecise_release
+  // CHECK-NEXT: ret void
+  Test1 *ptr = test1_helper();
+  char *c = [(ptr) interior];
+}
+
+// CHECK: define void @test1b()
+void test1b(void) {
+  // CHECK:      [[T0:%.*]] = call [[TEST1:%.*]]* @test1_helper()
+  // CHECK-NEXT: [[T1:%.*]] = bitcast [[TEST1]]* [[T0]] to i8*
+  // CHECK-NEXT: [[T2:%.*]] = call i8* @objc_retainAutoreleasedReturnValue(i8* [[T1]])
+  // CHECK-NEXT: [[T3:%.*]] = bitcast i8* [[T2]] to [[TEST1]]*
+  // CHECK-NEXT: store [[TEST1]]* [[T3]]
+  // CHECK-NEXT: [[T0:%.*]] = load [[TEST1]]**
+  // CHECK-NEXT: [[T1:%.*]] = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_
+  // CHECK-NEXT: [[T2:%.*]] = bitcast [[TEST1]]* [[T0]] to i8*
+  // CHECK-NEXT: [[T3:%.*]] = call i8* bitcast
+  // CHECK-NEXT: store i8* [[T3]], i8**
+  // CHECK-NEXT: [[T0:%.*]] = load [[TEST1]]**
+  // CHECK-NEXT: [[T1:%.*]] = bitcast [[TEST1]]* [[T0]] to i8*
+  // CHECK-NEXT: call void @objc_release(i8* [[T1]]) [[NUW]]
+  // CHECK-NOT:  clang.imprecise_release
+  // CHECK-NEXT: ret void
+  __attribute__((objc_precise_lifetime)) Test1 *ptr = test1_helper();
+  char *c = [ptr interior];
+}
+
+@interface Test2 {
+@public
+  id ivar;
+}
+@end
+// CHECK:      define void @test2(
+void test2(Test2 *x) {
+  x->ivar = 0;
+  // CHECK:      [[X:%.*]] = alloca [[TEST2:%.*]]*
+  // CHECK-NEXT: [[T0:%.*]] = bitcast [[TEST2]]* {{%.*}} to i8*
+  // CHECK-NEXT: [[T1:%.*]] = call i8* @objc_retain(i8* [[T0]]) [[NUW]]
+  // CHECK-NEXT: [[T2:%.*]] = bitcast i8* [[T1]] to [[TEST2]]*
+  // CHECK-NEXT: store [[TEST2]]* [[T2]], [[TEST2]]** [[X]],
+
+  // CHECK-NEXT: [[T0:%.*]] = load [[TEST2]]** [[X]],
+  // CHECK-NEXT: [[OFFSET:%.*]] = load i64* @"OBJC_IVAR_$_Test2.ivar"
+  // CHECK-NEXT: [[T1:%.*]] = bitcast [[TEST2]]* [[T0]] to i8*
+  // CHECK-NEXT: [[T2:%.*]] = getelementptr inbounds i8* [[T1]], i64 [[OFFSET]]
+  // CHECK-NEXT: [[T3:%.*]] = bitcast i8* [[T2]] to i8**
+  // CHECK-NEXT: [[T4:%.*]] = load i8** [[T3]],
+  // CHECK-NEXT: store i8* null, i8** [[T3]],
+  // CHECK-NEXT: call void @objc_release(i8* [[T4]]) [[NUW]]
+  // CHECK-NOT:  imprecise
+
+  // CHECK-NEXT: [[T0:%.*]] = load [[TEST2]]** [[X]]
+  // CHECK-NEXT: [[T1:%.*]] = bitcast [[TEST2]]* [[T0]] to i8*
+  // CHECK-NEXT: call void @objc_release(i8* [[T1]]) [[NUW]], !clang.imprecise_release
+
+  // CHECK-NEXT: ret void
+}
+
+// CHECK:      define void @test3(i8*
+void test3(PRECISE_LIFETIME id x) {
+  // CHECK:      [[X:%.*]] = alloca i8*,
+  // CHECK-NEXT: [[T0:%.*]] = call i8* @objc_retain(i8* {{%.*}}) [[NUW]]
+  // CHECK-NEXT: store i8* [[T0]], i8** [[X]],
+
+  // CHECK-NEXT: [[T0:%.*]] = load i8** [[X]]
+  // CHECK-NEXT: call void @objc_release(i8* [[T0]]) [[NUW]]
+  // CHECK-NOT:  imprecise_release
+
+  // CHECK-NEXT: ret void  
+}
+
+// CHECK: attributes [[NUW]] = { nounwind }
diff --git a/clang/test/CodeGenObjC/arc.m b/clang/test/CodeGenObjC/arc.m
index 48f012a42be..0ef3d895105 100644
--- a/clang/test/CodeGenObjC/arc.m
+++ b/clang/test/CodeGenObjC/arc.m
@@ -273,27 +273,7 @@ void test8() {
   // CHECK:      [[X:%.*]] = alloca i8*
   // CHECK-NEXT: [[T0:%.*]] = call i8* @test8_helper()
   // CHECK-NEXT: store i8* [[T0]], i8** [[X]]
-  // CHECK-NEXT: call void @objc_release(i8* [[T0]]) [[NUW]]
-  // CHECK-NOT:  imprecise_release
-  // CHECK-NEXT: ret void
-}
-
-id test9_helper(void) __attribute__((ns_returns_retained));
-void test9() {
-  id x __attribute__((objc_precise_lifetime)) = test9_helper();
-  x = 0;
-  // CHECK:      [[X:%.*]] = alloca i8*
-  // CHECK-NEXT: [[CALL:%.*]] = call i8* @test9_helper()
-  // CHECK-NEXT: store i8* [[CALL]], i8** [[X]]
-
-  // CHECK-NEXT: [[T1:%.*]] = load i8** [[X]]
-  // CHECK-NEXT: store i8* null, i8** [[X]]
-  // CHECK-NEXT: call void @objc_release(i8* [[T1]]) [[NUW]], !clang.imprecise_release
-
-  // CHECK-NEXT: [[T1:%.*]] = load i8** [[X]]
-  // CHECK-NEXT: call void @objc_release(i8* [[T1]]) [[NUW]]
-  // CHECK-NOT:  clang.imprecise_release
-
+  // CHECK-NEXT: call void @objc_release(i8* [[T0]]) [[NUW]], !clang.imprecise_release
   // CHECK-NEXT: ret void
 }
 
@@ -1239,57 +1219,6 @@ void test56_test(void) {
 // CHECK-NEXT: [[T5:%.*]] = load i8** [[T4]]
 // CHECK-NEXT: ret i8* [[T5]]
 
-// rdar://problem/9821110
-@interface Test58
-- (char*) interior __attribute__((objc_returns_inner_pointer));
-// Should we allow this on properties?
-@end
-extern Test58 *test58_helper(void);
-
-// CHECK: define void @test58a()
-void test58a(void) {
-  // CHECK:      [[T0:%.*]] = call [[TEST58:%.*]]* @test58_helper()
-  // CHECK-NEXT: [[T1:%.*]] = bitcast [[TEST58]]* [[T0]] to i8*
-  // CHECK-NEXT: [[T2:%.*]] = call i8* @objc_retainAutoreleasedReturnValue(i8* [[T1]])
-  // CHECK-NEXT: [[T3:%.*]] = bitcast i8* [[T2]] to [[TEST58]]*
-  // CHECK-NEXT: store [[TEST58]]* [[T3]]
-  // CHECK-NEXT: [[T0:%.*]] = load [[TEST58]]**
-  // CHECK-NEXT: [[T1:%.*]] = bitcast [[TEST58]]* [[T0]] to i8*
-  // CHECK-NEXT: [[T2:%.*]] = call i8* @objc_retainAutorelease(i8* [[T1]])
-  // CHECK-NEXT: [[T3:%.*]] = bitcast i8* [[T2]] to [[TEST58]]*
-  // CHECK-NEXT: [[T4:%.*]] = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_
-  // CHECK-NEXT: [[T5:%.*]] = bitcast [[TEST58]]* [[T3]] to i8*
-  // CHECK-NEXT: [[T6:%.*]] = call i8* bitcast
-  // CHECK-NEXT: store i8* [[T6]], i8**
-  // CHECK-NEXT: [[T0:%.*]] = load [[TEST58]]**
-  // CHECK-NEXT: [[T1:%.*]] = bitcast [[TEST58]]* [[T0]] to i8*
-  // CHECK-NEXT: call void @objc_release(i8* [[T1]]) [[NUW]], !clang.imprecise_release
-  // CHECK-NEXT: ret void
-  Test58 *ptr = test58_helper();
-  char *c = [(ptr) interior];
-}
-
-// CHECK: define void @test58b()
-void test58b(void) {
-  // CHECK:      [[T0:%.*]] = call [[TEST58:%.*]]* @test58_helper()
-  // CHECK-NEXT: [[T1:%.*]] = bitcast [[TEST58]]* [[T0]] to i8*
-  // CHECK-NEXT: [[T2:%.*]] = call i8* @objc_retainAutoreleasedReturnValue(i8* [[T1]])
-  // CHECK-NEXT: [[T3:%.*]] = bitcast i8* [[T2]] to [[TEST58]]*
-  // CHECK-NEXT: store [[TEST58]]* [[T3]]
-  // CHECK-NEXT: [[T0:%.*]] = load [[TEST58]]**
-  // CHECK-NEXT: [[T1:%.*]] = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_
-  // CHECK-NEXT: [[T2:%.*]] = bitcast [[TEST58]]* [[T0]] to i8*
-  // CHECK-NEXT: [[T3:%.*]] = call i8* bitcast
-  // CHECK-NEXT: store i8* [[T3]], i8**
-  // CHECK-NEXT: [[T0:%.*]] = load [[TEST58]]**
-  // CHECK-NEXT: [[T1:%.*]] = bitcast [[TEST58]]* [[T0]] to i8*
-  // CHECK-NEXT: call void @objc_release(i8* [[T1]]) [[NUW]]
-  // CHECK-NOT:  clang.imprecise_release
-  // CHECK-NEXT: ret void
-  __attribute__((objc_precise_lifetime)) Test58 *ptr = test58_helper();
-  char *c = [ptr interior];
-}
-
 // rdar://problem/9842343
 void test59(void) {
   extern id test59_getlock(void);