[MPlayer-advusers] gcc, mplayer and profile (mcount)

[Adam Sulmicki]

Hello folks,

 	This is my last post on the subject of mcount.

 	I have spent a quite bit of time on this to find out
 	that the results of myserious crashes is the mcount variable.
 	(with help from Ian Lance Taylor).

 	I have reported the issue to both gcc and mplayer lists, and
 	from _BOTH_ lists I got reply that they do not feel it is their
 	problem and blamed the other package.

 	WELL, as far as I'm concerned the issue is solved, I know how to
 	fix it and works for me.

 	In spirit making OSS better, I took the extra effor to report
 	findings back to both lists. In reward I got flamed on both list.

The Issue:

 	Anyway, the scop is that once I try to compile mplayer with
 	-pg option (or -p) then it will start myseriously crash on
 	mplayer/libmenu/menu.c:menu_init().

 	It comes out that  in mplayer/libmenu/menu.c there's in use
 	"mcount" variable:

 		# grep mcount menu.c
 		static int mcount = 0;

 	however, once "-pg" or "-p" options are enabled,
 	gcc uses mcount _function_ for its internal profiling.

 	The results are mysterious crashes on menu_init().

Suggested solutions:

 	* Rename mcount in mplayer/libmenu/menu.c to something else.

 	* document mcount in gcc man page

 	* gcc prints warning.

 	* do nothing.

I can immagine that gcc developers might have intentionally left mcount() 
visible to user space so that user can replace gcc's mcount() with their 
own implementation.

Just FWIW, I don't care if anything will get done about it.

-- 
Adam Sulmicki
http://www.eax.com 	The Supreme Headquarters of the 32 bit registers