Re: [RFA/dwarf] Eliminate dwarf2_tmp_obstack

Jim Blandy
2004-04-19T18:15:19Z

Daniel Jacobowitz <drow@false.org> writes:

> On Mon, Apr 19, 2004 at 01:32:38AM -0500, Jim Blandy wrote:
> >
> > Daniel Jacobowitz <drow@false.org> writes:
> > > dwarf2_tmp_obstack serves as a general purpose dumping ground. After my
> > > previous patches, there are only two things left on it: the linked list we
> > > use to fudge GCC 2.95 line number tables (some day soon I think this hack
> > > should go away; it was primarily for the benefit of the testsuite, and was
> > > fixed at least as of GCC 3.1), and the block structures created in
> > > read_attribute_value.
> > >
> > > Both of these are clearly associated with a particular compilation unit.
> > > If we put them on the comp_unit_obstack, then we don't have any need for
> > > the global obstack any more.
> > >
> > > Since my following patches change the lifetimes of individual CUs, I felt
> > > this was a worthwhile cleanup. OK?
> >
> > You need to fix up the comments above free_stack_comp_unit; it's no
> > longer "only used during partial symbol processing".
>
> Will do.
>
> > I'd like free_stack_comp_unit renamed to free_comp_unit_obstack, so
> > that when I search for comp_unit_obstack, I'll also run into the calls
> > to make_cleanup that will free it.
> >
> > Otherwise, looks good.
>
> Mind if I don't do this one? Right now, we have:
>
> /* This cleanup function is passed the address of a dwarf2_cu on the stack
> when we're finished with it. We can't free the pointer itself, but
> release any associated storage.
>
> But on the intercu branch, it says:
>
> /* This cleanup function is passed the address of a dwarf2_cu on the stack
> when we're finished with it. We can't free the pointer itself, but be
> sure to unlink it from the cache. Also release any associated storage
> and perform cache maintenance.
>
> The most important thing the function does is remove a pointer from the
> objfile's compilation unit cache to the stack frame of the function
> that's ending.

So, it's supposed to do more than just free that obstack --- it does
whatever cleanups are necessary; for the more complicated structures
used in the full intercu code, that's more than freeing an obstack.
Okay, I'll go along with that.