Re: [ANNOUNCEMENT] mesa 11.0.9-2 [GOLDSTAR]

[Yaakov Selkowitz <yselkowitz@cygwin.com>]

On 6/6/2016 9:27 AM, Jon Turney wrote:
> On 06/06/2016 08:24, Yaakov Selkowitz wrote:
>> On 2016-06-03 12:56, Jon Turney wrote:
>>> On 31/05/2016 18:03, Jon Turney wrote:
>>>>> # gdb ./quad-clip
>>>>> [...]
>>>>> (gdb) r
>>>>> [...]
>>>>> Program received signal SIGSEGV, Segmentation fault.
>>>>> 0x7fdf00c1 in ?? ()
>>> [...]
>>>>> /usr/src/debug/mesa-demos-8.3.0-1/src/trivial/quad-clip.c:137
>>>>> (gdb) disassemble 0x7fdf00b1,0x7fdf00d2
>>>>> Dump of assembler code from 0x7fdf00b1 to 0x7fdf00d2:
>>>>>    0x7fdf00b1:  insertps $0x10,0x4(%eax,%edi,1),%xmm0
>>>>>    0x7fdf00b9:  insertps $0x20,0x8(%eax,%edi,1),%xmm0
>>>>> => 0x7fdf00c1:  insertps $0x30,0xfffeff34,%xmm0
>>>>>    0x7fdf00cb:  mov    (%esi),%eax
>>>>>    0x7fdf00cd:  mul    %ecx
>>>
>>> After staring this a bit more, I see that this is the offset to the data
>>> to load, apparently being used as an absolute address
>>>
>>> This seems to be the case with other addresses in the JIT-ed code,  so
>>> perhaps there is some problem preventing relocations being applied...
>>
>> FWIW, I tried rebuilding with llvm 3.8.0.  32-bit doesn't crash anymore,
>> and glxgears says its running, but only the background shows.
>
> Thanks, that was next on my list to try
>
> That sounds exactly like what I see with llvm svn r251761 [1] backported
> to 3.7.1 (without which we use the x86_64 loader on x86, rather than
> reporting an error, due to an interesting use of __builtin_undefined,
> with hilarious consequences)
>
> I guess the output of the JIT code is ending up the wrong place as well,
> or something...

For the record, Jon seems to have tracked this down, and his fix is in 
llvm-3.7.1-2.  I can only imagine what "fun" he had debugging this, 
particularly on the address-starved 32-bit platform.

Andrew, could you please do the honours?

-- 
Yaakov

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