[LLVMdev] noreturn attribute on a call instruction vs noreturn on a function

[Kostya Serebryany]

On Wed, Nov 28, 2012 at 8:05 PM, Duncan Sands <baldrick at free.fr> wrote:

> Hi Kostya,
>
>
> On 28/11/12 14:47, Kostya Serebryany wrote:
>
>> Hi,
>>
>> Building the following C code I get a call instruction that has no
>> noreturn
>> attribute, while the function itself does have it.
>>
>> void foo(void **b) {
>>    __builtin_longjmp(b, 1);
>> }
>>
>>
>> define void @_Z3fooPPv(i8** %b) noreturn nounwind uwtable {
>> entry:
>>    %0 = bitcast i8** %b to i8*
>>    tail call void @llvm.eh.sjlj.longjmp(i8* %0)
>> <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<**<<<<<<
>>    unreachable
>> }
>>
>> declare void @llvm.eh.sjlj.longjmp(i8*) noreturn nounwind
>>  <<<<<<<<<<<<<<<<<
>>
>>
>> I've hit this in asan where it checks the noreturn attribute in the call
>> instruction, but not in the function object.
>> Who is wrong here? Should asan also check noreturn in the called function?
>>
>
> I think you should consider the call no-return if either the call or the
> callee has the no-return attribute.
>

Thanks, I've fixed this in asan pass.

--kcc



>
> Ciao, Duncan.
>
>
>> Thanks,
>>
>> --kcc
>>
>>
>>
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>>
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