Re: Any hints on this problem? Thanks!

[Jan Hubicka <hubicka at ucw dot cz>]

> ?? wrote:
> >    Now, my question becomes clear. How to make my inserted function call
> >not affect the orginal state of program?
> 
> Try looking at a similar feature.  One such similar feature is the 
> mcount calls emitted for profiling.  The various solutions for mcount 
> include
> 1) saving lots of registers before the call, and restoring lots of 
> registers after the call.  This has a high cost which may not work in 
> your case.
> 2) Writing mcount in assembly language, so that you can avoid clobbering 
> any registers.

Actually I would say that copying mcount code would be dificult (because
we need to emit the calls at arbitrary basic blocks rather than in
prologue) and not very maintanale. I belive that it would be better to
simply insert the calls at gimple level like edge/value profiling is
done.
Using custom calling conventions to speed process up might be
interesting, I guess it can be done via target hook+attribute but I
would leave it for later time.

Honza