On Fri, 2011-02-25 at 19:57 +0000, Dave Korn wrote:
> On 25/02/2011 19:21, Kyle Girard wrote:
>
> > I was hoping to see the assignment.
>
> > Looking at the gimple output there is no way to see that 'a' was
> > assigned in bar(). So that it can be used in wik(). Am I
> > misunderstanding something shouldn't there be a way to see the
> > assignment in bar? Do I have to parse the expression statement or are
> > things already optimized away and there is no way to get the information
> > that I seek.
>
> Ah, right. Yes, the stuff you see at the GIMPLE level has already been
> substantially processed compared to the original AST - operations decomposed,
> constants folded, that kind of thing. For instance if (like Andrew suggests)
> we add a "int x;" declaration in class A from your original example, we get:
>
> > void foo::bar(A&) (struct foo * const this, struct A & aa)
> > {
> > this->a = MEM[(const struct A &)aa];
> > }
>
Ok that's starting to make a little bit more sense...
> You probably need to look earlier than GIMPLE time. What plugin event are
> you hooking?
Currently, I try to get the earliest GIMPLE possible by using creating
my own pass like this
struct register_pass_info pass_info;
pass_info.pass = &myPass;
pass_info.reference_pass_name = all_lowering_passes->name;
pass_info.ref_pass_instance_number = 0;
pass_info.pos_op = PASS_POS_INSERT_AFTER;
register_callback(pluginName, PLUGIN_PASS_MANAGER_SETUP, NULL,
&pass_info);
Which, if I understand correctly gets me in before any major
optimization happens to the GIMPLE. But by the sounds of it I will need
to go earlier somehow for some methods/functions. Is it possible to be
an earlier pass and still have proper GIMPLE?
or can i hook in earlier and sort of put my own artificial GIMPLE in
somehow? If that is possible how would I know when the to fake the
GIMPLE and when not to?
Cheers,
Kyle
