[FFmpeg-devel] [PATCH] fix h264_deblock_sse2.asm segfaults on clang/x86-32

Ronald S. Bultje rsbultje
Wed Sep 1 08:01:36 CEST 2010


On Wed, Sep 1, 2010 at 1:53 AM, Reimar D?ffinger
<Reimar.Doeffinger at gmx.de> wrote:
> On Tue, Aug 31, 2010 at 07:06:09PM -0400, Ronald S. Bultje wrote:
>> on fate/clang/freebsd/x86-32 [1], all h264 tests fail with a sigbus.
>> There's some alignment issues in the sse2 asm. The asm appears to
>> assume that the caller function guarantees a certain alignment, which
>> is (IMO) not necessarily true. If the function is called directly from
>> C, stack can have any alignment, depending on the compiler used, so
>> the functions shouldn't assume any specific alignment imo.
> We already use
> attribute_align_arg

Alex brought that up also. That sets alignment of stack in functions,
not functions called by functions (afaics). Since these are compiled
by yasm, they're unaffected by that.

Or clang is buggy, who knows... :-).


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