Generating gimple statements from pragma's

[Julien Peeters <jj.peeters@xxxxxxxxx>]

Hi ML Readers,

I am looking for help to make a GCC plugin.

The plugin aims to add pragma's to GCC. These pragma's would have the 
effect of inserting calls to runtime library functions a very specific 
points in the code.

Here is an example:

If I write:

int a, b;

...

#pragma mypragma opt(a, b)
{
    int c;
    c = b;
    a += c;
    b = a;
}

the resulting gimple should be equivalent to this:

int a, b;

...

runtime_start ();
runtime_require ( a );
runtime_require ( b );
runtime_check ();
{
    int c;
    c = b;
    a += c;
    b = a;
}
runtime_finalize ();

I found in the examples how to add pragma's but I am not sure how can I 
detect the block next to the pragma, check that all variable in the opt 
option are accessible in the scope of the block and finally how can I 
add calls to the runtime functions.

Thanks for helping,
Julien.