[PATCH 1/2, AARCH64]: Machine descriptions: Re: [RFC] [PATCH, AARCH64] : Using standard patterns for stack protection.

[Venkataramanan Kumar <venkataramanan dot kumar at linaro dot org>]

Hi Marcus,

On 14 March 2014 19:42, Marcus Shawcroft <marcus.shawcroft@gmail.com> wrote:
> Hi Venkat
>
> On 5 February 2014 10:29, Venkataramanan Kumar
> <venkataramanan.kumar@linaro.org> wrote:
>> Hi Marcus,
>>
>>> +  "ldr\\t%x2, %1\;str\\t%x2, %0\;mov\t%x2,0"
>>> +  [(set_attr "length" "12")])
>>>
>>> This pattern emits an opaque sequence of instructions that cannot be
>>> scheduled, is that necessary? Can we not expand individual
>>> instructions or at least split ?
>>
>> Almost all the ports emits a template of assembly instructions.
>> I m not sure why they have to be generated this way.
>> But usage of these pattern is to clear the register that holds canary
>> value immediately after its usage.
>
> I've just read the thread Andrew pointed out, thanks, I'm happy that
> there is a good reason to do it this way.  Andrew, thanks for
> providing the background.
>
> +  [(set_attr "length" "12")])
> +
>
> These patterns should also set the "type" attribute,  a reasonable
> value would be "multiple".
>

I have incorporated your review comments and split the patch into two.

The first patch attached here contains Aarch64 machine descriptions
for the stack protect patterns.

ChangeLog.

2014-03-19 Venkataramanan Kumar  <venkataramanan.kumar@linaro.org>
        * config/aarch64/aarch64.md (stack_protect_set, stack_protect_test)
        (stack_protect_set_<mode>, stack_protect_test_<mode>): Add
        machine descriptions for Stack Smashing Protector.

Tested  for aarch64-none-linux-gnu target under QEMU .

regards,
Venkat.

Attachment: gcc.stack.protect.aarch64.txt
Description: Text document