[PATCH 4/4] x86: Add 'V' register operand modifier

[Florian Weimer]

* H. J. Lu:

> On Fri, Jan 12, 2018 at 10:00 AM, Jan Hubicka <hubicka@ucw.cz> wrote:
>>> Add 'V', a special modifier which prints the name of the full integer
>>> register without '%'.  For
>>>
>>> extern void (*func_p) (void);
>>>
>>> void
>>> foo (void)
>>> {
>>>   asm ("call __x86_indirect_thunk_%V0" : : "a" (func_p));
>>> }

>> Seems reasonable. Purpose of this is to make posible to call thunks
>> from asm statements, right?
>
> Yes.

Can you actually do this in practice?  What about the red zone and CFI
annotations?