RFC: [PATCH] Add __builtin_ia32_stack_top
H.J. Lu
hjl.tools@gmail.com
Wed Jul 22 14:14:00 GMT 2015
On Wed, Jul 22, 2015 at 6:55 AM, Segher Boessenkool
<segher@kernel.crashing.org> wrote:
> On Wed, Jul 22, 2015 at 05:10:04AM -0700, H.J. Lu wrote:
>> I got a feedback, suggesting __builtin_stack_top, instead of
>> __builtin_ia32_stack_top. But I don't know if
>>
>> + /* After the prologue, stack top is at -WORD(AP) in the current
>> + frame. */
>> + emit_insn (gen_rtx_SET (target,
>> + plus_constant (Pmode, arg_pointer_rtx,
>> + -UNITS_PER_WORD)));
>>
>> is true for all backends. If it works on all backends, I can move
>> it to builtins.c.
>
> It doesn't afaik. But can't you define INITIAL_FRAME_ADDRESS_RTX?
>
>
> Segher
Does INITIAL_FRAME_ADDRESS_RTX point to stack top? It certainly
can't be defined for x86. I will write a midld-end patch and leave to each
backend to enable it.
--
H.J.
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