[PATCH][AArch64] Increase static buffer size in aarch64_rewrite_selected_cpu

[Kyrill Tkachov]

Ping on the backport.
Is this ok for the GCC 5 branch?

Thanks,
Kyrill

On 29/04/15 14:59, Kyrill Tkachov wrote:
> On 20/04/15 21:30, James Greenhalgh wrote:
>> On Mon, Apr 20, 2015 at 05:24:39PM +0100, Kyrill Tkachov wrote:
>>> Hi all,
>>>
>>> When trying to compile a testcase with -mcpu=cortex-a57+crypto+nocrc I got
>>> the weird assembler error:
>>> Assembler messages:
>>> Error: missing architectural extension
>>> Error: unrecognized option -mcpu=cortex-a57+crypto+no
>>>
>>> The problem is the aarch64_rewrite_selected_cpu that is used to rewrite -mcpu
>>> for big.LITTLE options has a limit of 20 characters in what it handles, which
>>> we can exhaust quickly if we specify architectural extensions in a
>>> fine-grained manner.
>>>
>>> This patch increases that character limit to 128 and adds an assert to
>>> confirm that no bad things happen.
>> You've implemented this as a hard ICE, was that intended?
>>
>>> It also fixes another problem: If we pass a big.LITTLE combination with
>>> feature modifiers like: -mcpu=cortex-a57.cortex-a53+nosimd
>>>
>>> the code will truncate everything after '.', thus destroying the extensions
>>> that we want to pass.  The patch adds code to stitch the extensions back on
>>> after the LITTLE cpu is removed.
>> UGH, I should not be allowed near strings! This code is on my list of
>> things I'd love to rewrite to this year! For now, this is OK and please
>> also queue it for 5.2 when that opens for patches.
> Hi all,
> Just to confirm.
> Is it ok to backport this patch to the GCC 5 branch?
>
> Thanks,
> Kyrill
>
>>> Ok for trunk?
>> Yes, thanks. And sorry again for introducing this in the first place.
>>
>> James
>>