Re: [CHKP, PATCH] Fix instrumented indirect calls with propagated pointers

[Ilya Enkovich <enkovich.gnu@gmail.com>]

2015-03-25 11:16 GMT+03:00 Jakub Jelinek <jakub@redhat.com>:
> On Wed, Mar 25, 2015 at 11:05:17AM +0300, Ilya Enkovich wrote:
>> > The question is what you want to do in the LTO case for the different cases,
>> > in particular a TU compiled with -fcheck-pointer-bounds and LTO link without
>> > that, or TU compiled without -fcheck-pointer-bounds and LTO link with it.
>> > It could be handled as LTO incompatible option, where lto1 would error out
>> > if you try to mix -fcheck-pointer-bounds with -fno-check-pointer-bounds
>> > code, or e.g. similar to var-tracking, you could consider adjusting the IL
>> > upon LTO reading if if some TU has been built with -fcheck-pointer-bounds
>> > and the LTO link is -fno-check-pointer-bounds.  Dunno what will happen
>> > with -fno-check-pointer-bounds TUs LTO linked with -fcheck-pointer-bounds.
>> > Or another possibility is to or in -fcheck-pointer-bounds from all TUs.
>>
>> Mixing instrumented and not instrumented TUs is allowed. All
>> instrumentation passes happen before LTO link. The only code
>> generation problem if instrumented code is linked with no
>> -fcheck-pointer-bounds is disabled chkp_finish_file call which
>> generates static constructors. I think I just should set
>> flag_check_pointer_bounds if see any instrumented symbol on LTO read.
>> It would cause chkp_finish_file call when required and would be
>> available as guard for chkp related codes.
>
> Thus perhaps oring the flag_check_pointer_bounds option from all the TUs is
> the desirable behavior for LTO?
> I think Richard or Honza would know where would be the best spot to do that.
>
>         Jakub

Is such oring used for some other flags to have an example?

Thanks,
Ilya