Re: Definition of BUG on x86

H. Peter Anvin
2009-02-19T20:10:47Z

Jeremy Fitzhardinge wrote:
> Ingo Molnar wrote:
>> Well, the important question is thatGCC will optimize out whatever
>> comes after the __builtin_trap(), right? To guarantee an assert we can
>> do something like:
>>
>> __builtin_trap();
>> panic("should never get here");
>>
>> to guarantee a message. (But realistically GCC will at most generate a
>> build error.)
>>
>
> Ah, right, I remember the problem. There's no guaranteed way of getting
> the address of the ud2a instruction __builtin_trap generates to put it
> into the bug table.
>

Did we actually run into any instance where that failed?

It's true that it's not guaranteed, but it seems highly unlikely that it
would happen in real life. We *could* do a forward search at that
point, that should catch the vast majority of the failing cases, again,
but once again there are no guarantees.

I guess I should ask the gcc people...

-hpa