On Wed, Aug 28, 2013 at 3:05 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> On Wed, Aug 28, 2013 at 02:57:01PM +0200, Marek Polacek wrote:
>> On Wed, Aug 28, 2013 at 02:49:54PM +0200, Richard Biener wrote:
>> > On Wed, Aug 28, 2013 at 2:15 PM, Marek Polacek <pola...@redhat.com> wrote:
>> > > On Wed, Aug 28, 2013 at 12:40:50PM +0200, Richard Biener wrote:
>> > >> On Tue, Aug 27, 2013 at 2:33 PM, Marek Polacek <pola...@redhat.com>
>> > >> wrote:
>> > >> > It turned out that for tree -> tree mapping we don't need the hash
>> > >> > table at all; pointer map is much more convenient. So this patch
>> > >> > weeds out the hash table out of ubsan and introduces pointer map
>> > >> > instead. Quite a lot of code could go away--no need to set the
>> > >> > alloc pools up etc.
>> > >> >
>> > >> > Regtested, ran bootstrap-ubsan on x86_64-linux. Applying to the
>> > >> > ubsan branch.
>> > >>
>> > >> You can use the type-safe pointer_map <tree> now (ok, only the data type
>> > >> is type safe, the pointer is still void).
>> > >
>> > > Thanks, done with the following. Please let me know if you see
>> > > something wrong in this; otherwise I'll commit it if the
>> > > bootstrap-ubsan passes.
>> >
>> > Probably misses freeing of the pointer-map using 'delete' somewhere.
>>
>> That's a problem, since ubsan is not a pass, we can't simply delete
>> the map at the end of the pass when it's not needed anymore...
>>
>> Perhaps some GTY(()) stuff could do it, but I don't know which one.
>
> You basically want to keep the pointer map for as long as you can
> lookup types, which is done now from both FEs and
> middle-end? I guess it is the same category as say
> debug_expr_for_decl or value_expr_for_decl map tables, which we never free
> either. But for those we indeed
> GTY ((if_marked ("tree_decl_map_marked_p"), param_is (struct tree_decl_map)))
> and thus remove items if the original decl is not referenced from anywhere
> else; but pointer_map doesn't allow item removal; do we walk it for GC at
> all? If so, it might prevent some types from being GC collected, on the
> other side right now it isn't expected that too many types will be put into
> the map.
pointer-map is not GC enabled.
Richard.
> Jakub
