Re: Fix build of jit (was Re: [PATCH, RFC] Introduce -fsanitize=use-after-scope (v3))

["Martin Liška" <mliska@suse.cz>]

On 11/07/2016 05:17 PM, Jakub Jelinek wrote:
> On Mon, Nov 07, 2016 at 11:07:13AM -0500, David Malcolm wrote:
>> The patch (r241896) introduced an error in the build of the jit:
>>
>> ../../src/gcc/jit/jit-builtins.c:62:1: error: invalid conversion from
>> ‘int’ to ‘gcc::jit::built_in_attribute’ [-fpermissive]
>>  };
>>  ^
>>
>> which seems to be due to the "0" for ATTRS in:
>>
>> --- a/gcc/sanitizer.def
>> +++ b/gcc/sanitizer.def
>> @@ -165,6 +165,10 @@ DEF_SANITIZER_BUILTIN(BUILT_IN_ASAN_BEFORE_DYNAMIC_INIT,
>>  DEF_SANITIZER_BUILTIN(BUILT_IN_ASAN_AFTER_DYNAMIC_INIT,
>>  		      "__asan_after_dynamic_init",
>>  		      BT_FN_VOID, ATTR_NOTHROW_LEAF_LIST)
>> +DEF_SANITIZER_BUILTIN(BUILT_IN_ASAN_CLOBBER_N, "__asan_poison_stack_memory",
>> +		      BT_FN_VOID_PTR_PTRMODE, 0)
>> +DEF_SANITIZER_BUILTIN(BUILT_IN_ASAN_UNCLOBBER_N, "__asan_unpoison_stack_memory",
>> +		      BT_FN_VOID_PTR_PTRMODE, 0)
> 
> I believe the 0 here is a bug, I'd think we should be using something like
> ATTR_TMPURE_NOTHROW_LEAF_LIST that we are using __asan_load* - the functions
> aren't going to throw, nor call anything in the current TU.  Not 100% sure
> about the TMPURE, after all they do write/read memory (the shadow one).
> So maybe ATTR_NOTHROW_LEAF_LIST instead for now?  Martin?

Yes, 0 is bug. I'm inclining to ATTR_NOTHROW_LEAF_LIST as __asan_{un}poison_stack_memory
modifies global memory. It would be more safe. I'm also going to change it for ASAN_MARK
internal function (where ECF_TM_PURE is currently selected).

I'm testing patch for that.
Martin

> 
>> Is the attached patch OK as a fix? (assuming testing passes)  Or should
>> these builtins have other attrs?  (sorry, am not very familiar with the
>> sanitizer code).
> 
> 	Jakub
>