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Re: PATCH: Also check for `movl %esp, %ebp' for x32
On Sun, May 6, 2012 at 1:31 PM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
>> Date: Thu, 3 May 2012 23:50:03 +0200 (CEST)
>> From: Mark Kettenis <mark.kettenis@xs4all.nl>
>>
>> > >> I did have a look at it, but still have some questions.
>> > >>
>> > >>> Hi,
>> > >>>
>> > >>> X32 may use `movl %esp, %ebp' in prologue. ?This patch checks it for
>> > >>> x32. ?Tested on Linux/x86-64. ?OK for trunk?
>> > >>
>> > >> But the prologues generated by various compilers are expected to be
>> > >> otherwise the same for both the x32 ABI and the normal 64-bit ABI? ?I
>> > >> guess x32 has to use "pushq %rbp" as "pushl %ebp" isn't available.
>> > >> And I guess you want to keep the stack 16-byte aligned anyway. ?I
>> > >> suppose that "movq %rsp, %rbp" is still ok for x32, but "movl %esp,
>> > >> %ebp" can be encoded in less bytes, so it might be a bit more
>> > >> efficient for x32.
>> > >
>> > > That is correct.
>> >
>> > Is my patch OK to install?
>>
>> Sorry, no. ?I'm really unhappy with that multi-line if clause. ?It
>> really is hard to parse. ?I'm trying to come up with a suggestion to
>> make this better, but so far haven't succeeded.
>
> OK, below is what I'd prefer to check in. ?No regressions on
> OpenBSD/amd64 (which will only ever support the "real" LP64 ABI).
> H.J. can you check that this indeed does the right thing for X32?
>
>
> 2012-05-06 ?Mark Kettenis ?<kettenis@gnu.org>
> ? ? ? ? ? ?H.J. Lu ?<hongjiu.lu@intel.com>
>
> ? ? ? ?* amd64-tdep.c (amd64_analyze_prologue): Additionally check for
> ? ? ? ?`movl %esp, %ebp' for the X32 ABI.
>
It works fine for x32.
Thanks.
--
H.J.