[cfe-commits] r171555 - in /cfe/trunk: lib/CodeGen/CGBlocks.cpp test/CodeGenObjC/arc-unoptimized-byref-var.m

[Fariborz Jahanian]

On Jan 4, 2013, at 3:56 PM, John McCall wrote:

> On Jan 4, 2013, at 3:32 PM, Fariborz Jahanian <fjahanian at apple.com> wrote:
>> Author: fjahanian
>> Date: Fri Jan  4 17:32:24 2013
>> New Revision: 171555
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=171555&view=rev
>> Log:
>> objective-C arc: in copy helper function for 
>> __strong __block variables, perform objc_storeStrong on
>> source and destination instead of direct move. This 
>> is done with -O0 and to improve some analysis.
>> // rdar://12530881
>> 
>> Added:
>>   cfe/trunk/test/CodeGenObjC/arc-unoptimized-byref-var.m
>> Modified:
>>   cfe/trunk/lib/CodeGen/CGBlocks.cpp
>> 
>> Modified: cfe/trunk/lib/CodeGen/CGBlocks.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGBlocks.cpp?rev=171555&r1=171554&r2=171555&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/CodeGen/CGBlocks.cpp (original)
>> +++ cfe/trunk/lib/CodeGen/CGBlocks.cpp Fri Jan  4 17:32:24 2013
>> @@ -1565,6 +1565,11 @@
>>    llvm::Value *null =
>>      llvm::ConstantPointerNull::get(cast<llvm::PointerType>(value->getType()));
>> 
>> +    if (CGF.CGM.getCodeGenOpts().OptimizationLevel == 0) {
>> +      CGF.EmitARCStoreStrongCall(destField, value, /*ignored*/ true);
>> +      CGF.EmitARCStoreStrongCall(srcField, null, /*ignored*/ true);
>> +      return;
>> +    }
>>    llvm::StoreInst *store = CGF.Builder.CreateStore(value, destField);
>>    store->setAlignment(Alignment.getQuantity());
>> 
>> 
>> Added: cfe/trunk/test/CodeGenObjC/arc-unoptimized-byref-var.m
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenObjC/arc-unoptimized-byref-var.m?rev=171555&view=auto
>> ==============================================================================
>> --- cfe/trunk/test/CodeGenObjC/arc-unoptimized-byref-var.m (added)
>> +++ cfe/trunk/test/CodeGenObjC/arc-unoptimized-byref-var.m Fri Jan  4 17:32:24 2013
>> @@ -0,0 +1,14 @@
>> +// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -fblocks -fobjc-arc -fobjc-runtime-has-weak -o - %s | FileCheck -check-prefix=CHECK-UNOPT %s
>> +// rdar://12530881
>> +
>> +void test19() {
>> +   __block id x;
>> +// CHECK-UNOPT: define internal void @__Block_byref_object_copy
>> +// CHECK-UNOPT: [[X:%.*]] = getelementptr inbounds [[BYREF_T:%.*]]* [[VAR:%.*]], i32 0, i32 6
>> +// CHECK-UNOPT: [[X2:%.*]] = getelementptr inbounds [[BYREF_T:%.*]]* [[VAR1:%.*]], i32 0, i32 6
>> +// CHECK-UNOPT-NEXT: [[SIX:%.*]] = load i8** [[X2]], align 8
>> +// CHECK-UNOPT-NEXT: call void @objc_storeStrong(i8** [[X]], i8* [[SIX]]) nounwind
>> +// CHECK-UNOPT-NEXT: call void @objc_storeStrong(i8** [[X2]], i8* null) nounwind
>> +// CHECK-UNOPT-NEXT: ret void
> 
> You need to initialize the destination to null (with a simple store) before doing a storeStrong to it.
In r171572. This is I assume to prevent storeStrong from releasing the old value. I guess this should not happen
in this context,
- Fariborz

> 
> John.