On Wed, 3 Jan 2024, Nathaniel Shead wrote: > Linaro CI tells me that this patch caused regressions on ARM. I don't > have an ARM machine available to test on, but it appears to have been > caused by attempting to stream vtables as static data members, and ARM > having different behaviour with regards to when DECL_INTERFACE_KNOWN is > marked on vtables. > > I don't think treating vtables as static members here is desirable > anyway, though, so this version of the patch explicitly ignores them. > > Manually checking the assembly output for some of the noted regressions > on ARM with a cross-compiler, this seems to have worked. Otherwise > bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk if it > passes Linaro CI on ARM this time? > > -- >8 -- > > Static data members marked 'inline' should be emitted in TUs where they > are ODR-used. We need to make sure that statics imported from modules > are correctly added to the 'pending_statics' map so that they get > emitted if needed, otherwise the attached testcase fails to link.
Seems reasonable to me Just FYI for anyone else wondering about namespace-scope variables, it seems during stream-in they're added to a separate 'static_decls' vector via add_module_namespace_decl which wrapup_namespace_globals later handles emitting their definitions, so it makes sense to me to have analogous handling for class-scope variables. > > PR c++/112899 > > gcc/cp/ChangeLog: > > * cp-tree.h (note_variable_template_instantiation): Rename to... > (note_static_storage_variable): ...this. > * decl2.cc (note_variable_template_instantiation): Rename to... > (note_static_storage_variable): ...this. > * pt.cc (instantiate_decl): Rename usage of above function. > * module.cc (trees_in::read_var_def): Remember pending statics > that we stream in. > > gcc/testsuite/ChangeLog: > > * g++.dg/modules/init-4_a.C: New test. > * g++.dg/modules/init-4_b.C: New test. > > Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com> > --- > gcc/cp/cp-tree.h | 2 +- > gcc/cp/decl2.cc | 4 ++-- > gcc/cp/module.cc | 5 +++++ > gcc/cp/pt.cc | 2 +- > gcc/testsuite/g++.dg/modules/init-4_a.C | 9 +++++++++ > gcc/testsuite/g++.dg/modules/init-4_b.C | 11 +++++++++++ > 6 files changed, 29 insertions(+), 4 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/modules/init-4_a.C > create mode 100644 gcc/testsuite/g++.dg/modules/init-4_b.C > > diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h > index 1979572c365..ebd2850599a 100644 > --- a/gcc/cp/cp-tree.h > +++ b/gcc/cp/cp-tree.h > @@ -7113,7 +7113,7 @@ extern tree maybe_get_tls_wrapper_call (tree); > extern void mark_needed (tree); > extern bool decl_needed_p (tree); > extern void note_vague_linkage_fn (tree); > -extern void note_variable_template_instantiation (tree); > +extern void note_static_storage_variable (tree); > extern tree build_artificial_parm (tree, tree, tree); > extern bool possibly_inlined_p (tree); > extern int parm_index (tree); > diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc > index 0850d3f5bce..241216b0dfe 100644 > --- a/gcc/cp/decl2.cc > +++ b/gcc/cp/decl2.cc > @@ -910,10 +910,10 @@ note_vague_linkage_fn (tree decl) > vec_safe_push (deferred_fns, decl); > } > > -/* As above, but for variable template instantiations. */ > +/* As above, but for variables with static storage duration. */ > > void > -note_variable_template_instantiation (tree decl) > +note_static_storage_variable (tree decl) > { > vec_safe_push (pending_statics, decl); > } > diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc > index 0bd46414da9..7edc0e37af0 100644 > --- a/gcc/cp/module.cc > +++ b/gcc/cp/module.cc > @@ -11752,6 +11752,11 @@ trees_in::read_var_def (tree decl, tree > maybe_template) > DECL_INITIALIZED_P (decl) = true; > if (maybe_dup && DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P > (maybe_dup)) > DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl) = true; > + if (DECL_CONTEXT (decl) > + && RECORD_OR_UNION_TYPE_P (DECL_CONTEXT (decl)) > + && !DECL_TEMPLATE_INFO (decl) > + && !DECL_VTABLE_OR_VTT_P (decl)) > + note_static_storage_variable (decl); > } > DECL_INITIAL (decl) = init; > if (!dyn_init) > diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc > index f7063e09581..ce498750758 100644 > --- a/gcc/cp/pt.cc > +++ b/gcc/cp/pt.cc > @@ -27150,7 +27150,7 @@ instantiate_decl (tree d, bool defer_ok, bool > expl_inst_class_mem_p) > { > set_instantiating_module (d); > if (variable_template_p (gen_tmpl)) > - note_variable_template_instantiation (d); > + note_static_storage_variable (d); This is a latent issue/curiousity orthogonal to your patch, but it seems inconsistent that namespace-scope variable template instantiations get added to 'pending_statics' (which is intended for class-scope variables) rather than to 'static_decls' (which is intended for namespace-scope variables). I wonder if we should instead do: diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index 154ac76cb65..25921c97ffe 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -27155,7 +27155,12 @@ instantiate_decl (tree d, bool defer_ok, bool expl_inst_class_mem_p) { set_instantiating_module (d); if (variable_template_p (gen_tmpl)) - note_variable_template_instantiation (d); + { + if (DECL_CLASS_SCOPE_P (gen_tmpl)) + note_static_data_member (d); + else + vec_safe_push (static_decls, d); + } instantiate_body (td, args, d, false); } > instantiate_body (td, args, d, false) > } > > diff --git a/gcc/testsuite/g++.dg/modules/init-4_a.C > b/gcc/testsuite/g++.dg/modules/init-4_a.C > new file mode 100644 > index 00000000000..e0eb97b474e > --- /dev/null > +++ b/gcc/testsuite/g++.dg/modules/init-4_a.C > @@ -0,0 +1,9 @@ > +// PR c++/112899 > +// { dg-additional-options "-fmodules-ts" } > +// { dg-module-cmi M } > + > +export module M; > + > +export struct A { > + static constexpr int x = -1; > +}; > diff --git a/gcc/testsuite/g++.dg/modules/init-4_b.C > b/gcc/testsuite/g++.dg/modules/init-4_b.C > new file mode 100644 > index 00000000000..d28017a1d14 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/modules/init-4_b.C > @@ -0,0 +1,11 @@ > +// PR c++/112899 > +// { dg-module-do run } > +// { dg-additional-options "-fmodules-ts" } > + > +import M; > + > +int main() { > + const int& x = A::x; > + if (x != -1) > + __builtin_abort(); > +} > -- > 2.43.0 > >