Re: Fix PR43404, PR48470, PR64744 ICE on naked functions

[Alexander Basov <coopht at gmail dot com>]

ping

2015-06-29 16:32 GMT+03:00 Alexander Basov <coopht@gmail.com>:
> I've updated patch with attributes lookup.
> is it OK?
>
> --
> Alexander
>
> 2015-06-26 9:33 GMT+03:00 Alexander Basov <coopht@gmail.com>:
>> 2015-06-25 21:47 GMT+03:00 Jeff Law <law@redhat.com>:
>>> On 06/03/2015 02:15 PM, Alexander Basov wrote:
>>>>
>>>> Hello Jeff,
>>>> please find updated patch attached
>>>>
>>>>>> diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
>>>>>> index b190f91..c6db8a9 100644
>>>>>> --- a/gcc/cfgexpand.c
>>>>>> +++ b/gcc/cfgexpand.c
>>>>>> @@ -1382,7 +1382,15 @@ expand_one_var (tree var, bool toplevel, bool
>>>>>> really_expand)
>>>>>>      else
>>>>>>        {
>>>>>>          if (really_expand)
>>>>>> -        expand_one_stack_var (origvar);
>>>>>> +        {
>>>>>> +          if (!targetm.calls.allocate_stack_slots_for_args ())
>>>>>> +            error ("cannot allocate stack for variable %q+D, naked
>>>>>> function.",
>>>>>> +                   var);
>>>>>> +
>>>>>> +          expand_one_stack_var (origvar);
>>>>>> +        }
>>>>>
>>>>> So how do you know ORIGVAR is an argument here before issuing the
>>>>> error?  ie, shouldn't you verify that the underlying object is a
>>>>> PARM_DECL? If there's some way we already know we're dealing with a
>>>>> PARM_DECL, then just say so.
>>>>
>>>> In case of naked function stack should not be used not only for function
>>>> args, but also for any local variables.
>>>> So, i think we don't need to check if underlying object is a PARM_DECL.
>>>
>>> Then that would indicate that we're using the wrong test
>>> (allocate_stack_slot_for_args).  That hook is for whether or not arguments
>>> should have stack slots allocated.  Yet you're issuing an error for more
>>> than just PARM_DECLs.
>>>
>>> Shouldn't you instead be checking if the current function is a naked
>>> function or not by checking the attributes of the current function?
>>>
>>> Jeff
>>
>> What allocate_stack_slots_for_args  does, it only checks if current
>> function is naked or not.
>> May be it will be better to remove allocate_stack_slots_for_args and
>> replace if with explicit checking of naked attribute?
>>
>> --
>> Alexander



-- 
Alexander