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[ObjC] Pop all cleanups created in EmitObjCForCollectionStmt before 

exiting the for-in loop.

This commit fixes a bug where EmitObjCForCollectionStmt didn't pop
cleanups for captures.

For example, in the following for-in loop, a block which captures self
is passed to foo1:

for (id x in [self foo1:^{ use(self); }]) {
  use(x);
  break;
}

Previously, the code in EmitObjCForCollectionStmt wouldn't pop the
cleanup for the captured self before exiting the loop, which caused
code-gen to generate an IR in which objc_release was called twice on
the captured self.

This commit fixes the bug by entering a RunCleanupsScope before the
loop condition is evaluated and forcing its cleanup before exiting the
loop.

rdar://problem/16865751

Differential Revision: http://reviews.llvm.org/D18618

llvm-svn: 266147
This commit is contained in:
Akira Hatanaka 2016-04-12 23:10:58 +00:00
parent 16a7d637dd
commit 2d3690bc98
2 changed files with 54 additions and 4 deletions
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7
clang/lib/CodeGen/CGObjC.cpp
View File

@ -1485,6 +1485,8 @@ void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S){
ArrayType::Normal, 0);
Address ItemsPtr = CreateMemTemp(ItemsTy, "items.ptr");
RunCleanupsScope ForScope(*this);
// Emit the collection pointer. In ARC, we do a retain.
llvm::Value *Collection;
if (getLangOpts().ObjCAutoRefCount) {
@ -1725,10 +1727,7 @@ void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S){
if (DI)
DI->EmitLexicalBlockEnd(Builder, S.getSourceRange().getEnd());
// Leave the cleanup we entered in ARC.
if (getLangOpts().ObjCAutoRefCount)
PopCleanupBlock();
ForScope.ForceCleanup();
EmitBlock(LoopEnd.getBlock());
}

51
clang/test/CodeGenObjC/arc-foreach.m
View File

@ -170,4 +170,55 @@ void test3(NSArray *array) {
// CHECK-LP64-NEXT: br label [[L]]
}
@interface NSObject @end
@interface I1 : NSObject
- (NSArray *) foo1:(void (^)(void))block;
- (void) foo2;
@end
NSArray *array4;
@implementation I1 : NSObject
- (NSArray *) foo1:(void (^)(void))block {
block();
return array4;
}
- (void) foo2 {
for (id x in [self foo1:^{ use(self); }]) {
use(x);
break;
}
}
@end
// CHECK-LP64-LABEL: define internal void @"\01-[I1 foo2]"(
// CHECK-LP64: [[SELF_ADDR:%.*]] = alloca [[TY:%.*]]*,
// CHECK-LP64: [[BLOCK:%.*]] = alloca <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, [[TY]]* }>,
// CHECK-LP64: store [[TY]]* %self, [[TY]]** [[SELF_ADDR]]
// CHECK-LP64: [[T0:%.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, [[TY]]* }>, <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, [[TY]]* }>* [[BLOCK]], i32 0, i32 5
// CHECK-LP64: [[BC:%.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, [[TY]]* }>, <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, [[TY]]* }>* [[BLOCK]], i32 0, i32 5
// CHECK-LP64: [[T1:%.*]] = load [[TY]]*, [[TY]]** [[SELF_ADDR]]
// CHECK-LP64: [[T2:%.*]] = bitcast [[TY]]* [[T1]] to i8*
// CHECK-LP64: [[T3:%.*]] = call i8* @objc_retain(i8* [[T2]])
// CHECK-LP64: [[T4:%.*]] = bitcast i8* [[T3]] to [[TY]]*
// CHECK-LP64: store [[TY]]* [[T4]], [[TY]]** [[BC]]
// CHECK-LP64: [[T5:%.*]] = bitcast [[TY]]** [[T0]] to i8**
// CHECK-LP64: call void @objc_storeStrong(i8** [[T5]], i8* null)
// CHECK-LP64: switch i32 {{%.*}}, label %[[UNREACHABLE:.*]] [
// CHECK-LP64-NEXT: i32 0, label %[[CLEANUP_CONT:.*]]
// CHECK-LP64-NEXT: i32 2, label %[[FORCOLL_END:.*]]
// CHECK-LP64-NEXT: ]
// CHECK-LP64: {{^|:}}[[CLEANUP_CONT]]
// CHECK-LP64-NEXT: br label %[[FORCOLL_END]]
// CHECK-LP64: {{^|:}}[[FORCOLL_END]]
// CHECK-LP64-NEXT: ret void
// CHECK-LP64: {{^|:}}[[UNREACHABLE]]
// CHECK-LP64-NEXT: unreachable
// CHECK-LP64: attributes [[NUW]] = { nounwind }