On Thu, Feb 28, 2019 at 11:58 AM Jan Hubicka <hubi...@ucw.cz> wrote: > > Hi, > sorry for late reply - I did not identify it as a patch to symbol table. > Indeed we want can_refer_decl_in_current_unit_p is a good place to test > this. Is there a reason to resrict this to functions with no body?
If the function has a definition, then of course we can refer to it in its own unit. Am I missing something? > I see that we may be able to inline the function, but all the > devirtualization code works by first turning call to a direct call and > inlining later. We would need to teach the code that it can't > devirtualize without inlining (which can be done by the speculative call > macinery) and probably we will need to check that the function body does > not contain some calls to similar symbols. > > We don't have support for this (do we want to do that in future)? > For GCC 9 it would thus seem more consistent to simply return false on > all symbols with this combination of flags. We probably also can teach > symtab verifiers that we do not contain any references to such symbols. > > Thanks, > Honza > > Ping^3? > > > > On Wed, Feb 13, 2019 at 4:28 PM Jason Merrill <ja...@redhat.com> wrote: > > > > > > Ping^2 > > > > > > On Mon, Feb 4, 2019 at 4:09 PM Jason Merrill <ja...@redhat.com> wrote: > > > > > > > > Ping > > > > > > > > On Fri, Jan 25, 2019 at 10:06 AM Jason Merrill <ja...@redhat.com> wrote: > > > > > > > > > > Here we warn because i<l>::dispatch has internal linkage (because l > > > > > does) and is never instantiated (because the vtable is never emitted). > > > > > The regression happened because devirtualization started adding it to > > > > > cgraph as a possible target. I think the way to fix this is to avoid > > > > > adding an undefined internal function to cgraph as a possible target, > > > > > since it is not, in fact, possible for it to be the actual target. > > > > > > > > > > I think that the best place to fix this would be in > > > > > can_refer_decl_in_current_unit_p, since the same reasoning applies to > > > > > other possible references. But we could fix it only in > > > > > gimple_get_virt_method_for_vtable. > > > > > > > > > > First patch tested x86_64-pc-linux-gnu. > > > > >
