Re: __declspec(naked) and function body size

[Ilyes Gouta <ilyes dot gouta at gmail dot com>]

Hi,

Thank you for your reply!

Is it possible to get the size of a function, i.e the number of bytes generated by the compiler between the prologue and 
the final routine's ret instruction, so that it would be available through a 'sizeof' like operator for the other code?

It would be possible to do,

int a = sizeof(some_function);

I'm not expecting the standard sizeof to do that, but I'm looking for possibly another operator or some proprietary GCC 
extensions. I'm writing a JIT for my simplified C language and I'd like to copy template code around and patch it when 
necessary (and not only emitting opcode by opcode in the code buffers).

BR,
Ilyes Gouta.

Brian Dessent wrote:
> Ilyes Gouta wrote:
>
> > Is it possible using GCC? If yes, could you please tell me how?
>
> There is __attribute__((naked)) but it's not supported for x86.  I think
> the feeling is that gcc should be able to detect when a prologue is not
> necessary on its own and just not emit it, and that forcably disabling
> the prologue just results in horribly broken code if the function
> happens to require a spill.  See also
> <http://gcc.gnu.org/ml/gcc/2004-02/threads.html#00939>.
>
> Brian