[PATCH][X86] Trying to fix PR20243 - leaf frame pointer bug on X86, ELF, PIC

[Rafael Espíndola]

On 6 November 2014 09:00, Dario Domizioli <dario.domizioli at gmail.com> wrote:
>
> On 5 November 2014 19:55, Rafael Espíndola <rafael.espindola at gmail.com>
> wrote:
>>
>> The final lowering has to happen fairly late as the linker depends on
>> doing pattern matching for optimizing the different access.
>
>
> I see. That explains why it's expanded in AsmPrinter. And maybe even the
> reason why in some cases there is also some padding between the instructions
> (I imagine the linker would patch it up, right?).

Correct. Some sequences use more bytes than what would be strictly
necessary so that the linker can optimize linking a .o into a main
executable (for example).

>> Maybe instead of having a TLS_addr64 pseudo we could have it be an
>> actual call to an intrinsic and then special case the MC lowering
>
>
> Hm... that would require some reworking in the places where the pseudo
> instruction is handled, but it sounds like a good direction to investigate.
> I'll have a look at how to implement that.

Thanks,
Rafael