[Bug c++/80916] [7/8/9 Regression] Spurious "declared 'static' but never defined" warning
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80916 --- Comment #12 from Jason Merrill --- Author: jason Date: Thu Mar 7 15:10:22 2019 New Revision: 269459 URL: https://gcc.gnu.org/viewcvs?rev=269459=gcc=rev Log: PR c++/80916 - spurious "static but not defined" warning. Nothing can refer to an internal decl with no definition, so we shouldn't treat such a decl as a possible devirtualization target. * gimple-fold.c (can_refer_decl_in_current_unit_p): Return false for an internal symbol with DECL_EXTERNAL. Added: trunk/gcc/testsuite/g++.dg/warn/unused-fn1.C Modified: trunk/gcc/ChangeLog trunk/gcc/gimple-fold.c
[Bug c++/80916] [7/8/9 Regression] Spurious "declared 'static' but never defined" warning
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80916 Jason Merrill changed: What|Removed |Added CC||hubicka at gcc dot gnu.org --- Comment #11 from Jason Merrill --- Patch still waiting for review.
[Bug c++/80916] [7/8/9 Regression] Spurious "declared 'static' but never defined" warning
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80916 Jason Merrill changed: What|Removed |Added Keywords||patch --- Comment #10 from Jason Merrill --- Patch posted: https://gcc.gnu.org/ml/gcc-patches/2019-01/msg01512.html
[Bug c++/80916] [7/8/9 Regression] Spurious "declared 'static' but never defined" warning
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80916 --- Comment #9 from Jason Merrill --- It has internal linkage because one of its template arguments is a local class, and it isn't instantiated because it isn't ever used. It's added to cgraph as a possible devirtualization target. I think the last of these is the place to attack this issue, since it's also the source of the regression.
[Bug c++/80916] [7/8/9 Regression] Spurious "declared 'static' but never defined" warning
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80916 Jason Merrill changed: What|Removed |Added Status|NEW |ASSIGNED Assignee|unassigned at gcc dot gnu.org |jason at gcc dot gnu.org
[Bug c++/80916] [7/8/9 Regression] Spurious "declared 'static' but never defined" warning
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80916 --- Comment #8 from Davin McCall --- (In reply to ensadc from comment #7) > Note that the "never defined" part is also misleading: the warning persists > when `i::dispatch` does have a definition Yes; and actually, I note that in the original test case I supplied, the dispatch function doesn't have a definition, but it doesn't have internal linkage either. So, I think the warning really is spurious and it's not just a case of it saying "declared static" where it should say "has internal linkage".
[Bug c++/80916] [7/8/9 Regression] Spurious "declared 'static' but never defined" warning
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80916
--- Comment #7 from ensadc at mailnesia dot com ---
Note that the "never defined" part is also misleading: the warning persists
when `i::dispatch` does have a definition
(https://wandbox.org/permlink/MKif1shXFjt7aT6C):
struct j {
virtual void dispatch(void *) {}
};
template
struct i : j {
void dispatch(void *) {} // warning: 'void i<
>::dispatch(void*) [with = {anonymous}::l]' declared
'static' but never defined [-Wunused-function]
};
namespace {
struct l : i {};
}
void f(j *k) {
k->dispatch(0);
}
[Bug c++/80916] [7/8/9 Regression] Spurious "declared 'static' but never defined" warning
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80916 --- Comment #6 from Davin McCall --- > The wording could be improved, but why do you think the warning is spurious? I guess I think that the warning is spurious given the current wording? It may well be legitimate to warn that there is a declaration of a function with internal linkage but no definition, which may be what triggered this warning originally (it no longer triggers in my current code base, so I can't easily verify). But that's not what the warning does say. If you'd prefer to change the title to reflect that the wording of the warning doesn't match its cause, I have no issue with that.
[Bug c++/80916] [7/8/9 Regression] Spurious "declared 'static' but never defined" warning
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80916 Jakub Jelinek changed: What|Removed |Added CC||jakub at gcc dot gnu.org, ||jason at gcc dot gnu.org --- Comment #5 from Jakub Jelinek --- The wording could be improved, but why do you think the warning is spurious? While the method isn't static, it is effectively static, because it is internal linkage (i.e. visibility constrained to the current TU in which it is not really defined). If you ask for -Wunused-function, you get it if the compiler can figure it out. The reason it doesn't warn at -O0 is that it doesn't see it unless it tries to devirtualize. Not sure if we have a way to find out if !TREE_PUBLIC is because it has been declared static or because it has internal linkage and constrain_visibility VISIBILITY_ANON has been called on it (and would need a langhook anyway to determine that).
[Bug c++/80916] [7/8/9 Regression] Spurious "declared 'static' but never defined" warning
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80916 Richard Biener changed: What|Removed |Added Target Milestone|7.4 |7.5
[Bug c++/80916] [7/8/9 Regression] Spurious "declared 'static' but never defined" warning
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80916 Richard Biener changed: What|Removed |Added Priority|P3 |P2
[Bug c++/80916] [7/8/9 Regression] Spurious "declared 'static' but never defined" warning
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80916 Richard Biener changed: What|Removed |Added Target Milestone|--- |7.4
