develop a 'customized ld'

[sean yang]

>From: Ian Lance Taylor <ian@airs.com>
>To: "sean yang" <seanatpurdue@hotmail.com>
>CC: binutils@sourceware.org
>Subject: Re: develop a 'customized ld'
>Date: 10 Sep 2005 22:31:38 -0700
>
>"sean yang" <seanatpurdue@hotmail.com> writes:
>
> > > > You can use a gcc extension creatively to approximate this:
> > > >
> > > > void foo ()
> > > > {
> > > >  lab:
> > > >   printf ("%p\n", &&lab);
> > > > }
> > >
> > >But be careful with it - recent versions of GCC are pretty bad about
> > >preserving the addresses of labels not used for control flow.  I assume
> > >Ian's example will be OK, but if you don't have a computed goto which
> > >might target the label, GCC may just put it somewhere else...
> > Thanks to both of you. This is one conern, the other is I really don't
> > want to have extra intruction--if the programming load for
> > modification the binutils is not too heavy. Perticularly, I don't want
> > to have printf() in the final code. Could u give some more suggestion
> > on this?
>
>The printf was just an example of using the label.  The gcc extension
>is '&&' applied to a label.  See the gcc docs.
>
>You haven't really said what you want to do with the address.  If you
>don't want to use it in the program itself, then this approach is
>useless.
I would like to collect the information of call to some libc functions. I am 
not going to use it in the program itself but I am going to use it in a 
system  tool to watch the program's special calls.
Thanks,
Sean

>
>Ian

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