duplicate body remover

[Li Guanglei]

David Smith wrote:
> 
> This actually already exists, it just happens at a later stage.  If you 
> look at the generated C code, you'll see something like this:
> 
> =================
> static void probe_1480 (struct context * __restrict__ c) {
> ... normal systemtap initialization plus code to do 'log("here")' ...
> }
> 
> ...
> 
> static void probe_1481 (struct context * __restrict__ c) {
>   probe_1480 (c);
> }
> =================
> 

I noticed this. But what I mean is to step further to optimize 
enter_probe_*. e.g:

stap -e 'probe 
kernel.function("sys_*"),kernel.function("compat_sys_*") { log("here") 
}' -p3 > a.c

stap -e 'probe syscall.* { log("here") }' -p3 > b.c

on my x86_64, the size of a.c and b.c is:
[root@ltc-x326m-1 ~]# ll a.c b.c
-rw-r--r-- 1 root root  49503 Oct 20 08:39 a.c
-rw-r--r-- 1 root root 684419 Oct 20 08:39 b.c

a.c has 2 appearances of register_kprobe/enter_probe_* and b.c has 296 
of that. this is a big difference. Although it's not common to have 
the same body for different probe points, it will cause the generated 
c file really large in case someone use it.

- Guanglei