[Mesa-dev] [PATCH v2 1/2] virgl: Fix a strict-aliasing violation in the encoder

Edward O'Callaghan funfunctor at folklore1984.net
Tue Dec 6 22:34:20 UTC 2016



On 12/07/2016 12:36 AM, Emil Velikov wrote:
> On 6 December 2016 at 11:30, Edward O'Callaghan
> <funfunctor at folklore1984.net> wrote:
>> As per the C spec, it is illegal to alias pointers to different
>> types. This results in undefined behaviour after optimization
>> passes, resulting in very subtle bugs that happen only on a
>> full moon..
>>
>> Use a memcpy() as a well defined coercion between the double
>> to uint64_t interpretations of the memory.
>>
>> V.2: Use static_assert() instead of assert().
>>
> The lowercase static_assert is a c11 feature. You want to use the all
> caps version.
> See commit 23d1799f7dd5f8d1e8aa9f4efa6b1a4ed45faaa0

Hi Emil,

Why? I from that commit it seems only Android would have trouble however
virgl nor svga would want to be enabled on that platform?

Or is there something else I probably missed?

Kind Regards,
Edward.

> 
> We might want to use update the final vulkan [codebase] references, as well.
> 
> Thanks
> Emil
> 

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