[Patch PPC/Darwin] some tidy-ups for save_world (and a prelude to splitting it out of the rs6000 code).
Iain Sandoe
developer@sandoe-acoustics.co.uk
Sun Dec 4 20:24:00 GMT 2011
On 4 Dec 2011, at 06:35, Mike Stump wrote:
> On Nov 30, 2011, at 6:28 AM, Iain Sandoe wrote:
>> While trying to track down the vector unwind problems on ppc-
>> darwin, I made some tidy-ups for "save_world()".
>> In the end, that was not where the main problem, lay - but I did
>> find a few things wrong there on the way - they should be fixed,
>> even if there's no specific bug filed at present.
>>
>> I'm also attaching a second patch which is purely cosmetic white-
>> space/comment tidies I'd also like to apply.
>>
>> checked on powerpc-darwin{8-G4,9-G5} and crosses to powerpc-eabisim
>> and powerpc-ibm-aix6.1.3.0
>
>> - /* On Darwin, the unwind routines are compiled without
>> - TARGET_ALTIVEC, and use save_world to save/restore the
>> - altivec registers when necessary. */
>> + /* When generating code for earlier versions of Darwin, which
>> might run on
>> + hardware with or without Altivec, we use out-of-line save/
>> restores in
>> + function prologues/epilogues that require it. These routines
>> determine
>> + whether to save/restore Altivec at runtime. */
>
> So, we need to first settle on how the library is compiled before
> this becomes true...
The patch does not change any functionality here.
This was a ( clearly failed ;-) ) attempt to make the comment more
useful to newcomers to the code ...
(withdrawn, can think again sometime later).
>> +save_world:
>> + trap
>> +
>> + .private_extern eh_rest_world_r10
>> +eh_rest_world_r10:
>> + trap
>
> So, I can't see the necessity of doing this. I think it is bad
> style to generate code that will die at runtime. I'd rather have it
> not link.
done - there would now be a link fail if it were specified.
(although I would point out, FTR, that the code would have always
crashed if it had ever been invoked - since it was only m32 capable).
[[FWIW, I made a working m64 version, which we could resurrect should
there be some reason we decided that out-of-line world saves were
useful everywhere]]
OK for trunk?
Iain
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