return address in __cyg_profile_func_exit

return address in __cyg_profile_func_exit

[Laurent Burgy]

Hi,

I've been unable to find a high-level way of getting the original
return address of a function when entering __cyg_profile_func_exit.

__cyg_profile_func_exit is executed at the end of a function, is there
any way (with a builting) to retrieve the original returned value.
That would enable me to investigate the returned values without
modifying the calling site. The information must be somewhere but I
don't know how to reach it. (Getting EBX is not an option that I
consider since the value may depend on the level of optimization -i've
seen it only works with -O0).


Thanks...



--
Laurent Burgy

Re: return address in __cyg_profile_func_exit

[Andrew Haley]

Laurent Burgy wrote:

> I've been unable to find a high-level way of getting the original
> return address of a function when entering __cyg_profile_func_exit.
> 
> __cyg_profile_func_exit is executed at the end of a function, is there
> any way (with a builting) to retrieve the original returned value.
> That would enable me to investigate the returned values without
> modifying the calling site. The information must be somewhere but I
> don't know how to reach it. (Getting EBX is not an option that I
> consider since the value may depend on the level of optimization -i've
> seen it only works with -O0).

The return value is in EAX, but it isn't there when __cyg_profile_func_exit
is called.  It'd be quite easy to modify the compiler to do this, and not
possible otherwise.

Andrew.