On Wed, 3 Jan 2024, Nathaniel Shead wrote:
> Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk?
>
> -- >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.
>
> 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 | 4 ++++
> 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, 28 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..14818131a70 100644
> --- a/gcc/cp/module.cc
> +++ b/gcc/cp/module.cc
> @@ -11752,6 +11752,10 @@ 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))
> + note_static_storage_variable (decl);
It seems this should also handle templated inlines via
&& (!DECL_TEMPLATE_INFO (decl)
|| DECL_IMPLICIT_INSTANTIATION (decl))
otherwise the following fails to link:
$ cat init-5_a.H
template<bool _DecOnly>
struct __from_chars_alnum_to_val_table {
static inline int value = 42;
};
inline unsigned char
__from_chars_alnum_to_val() {
return __from_chars_alnum_to_val_table<false>::value;
}
$ cat init-6_b.C
import "init-5_a.H";
int main() {
__from_chars_alnum_to_val();
}
$ g++ -fmodules-ts -std=c++20 init-5_a.H init-5_b.C
/usr/bin/ld: /tmp/ccNRaads.o: in function `__from_chars_alnum_to_val()':
init-6_b.C:(.text._Z25__from_chars_alnum_to_valv[_Z25__from_chars_alnum_to_valv]+0x6):
undefined reference to `__from_chars_alnum_to_val_table<false>::value'
By the way I ran into this when testing out std::print with modules:
$ cat std.C
export module std;
export import <bits/stdc++.h>;
$ cat hello.C
import std;
int main() {
std::print("Hello {}!", "World");
}
$ g++ -fmodules-ts -std=c++26 -x c++-system-header bits/stdc++.h
$ g++ -fmodules-ts -std=c++26 std.C hello.C && ./a.out # before
/usr/bin/ld: /tmp/ccqNgOM1.o: in function `unsigned char
std::__detail::__from_chars_alnum_to_val<false>(unsigned char)':
hello.C:(.text._ZNSt8__detail25__from_chars_alnum_to_valILb0EEEhh[_ZNSt8__detail25__from_chars_alnum_to_valILb0EEEhh]+0x12):
undefined reference to
`std::__detail::__from_chars_alnum_to_val_table<false>::value'
$ g++ -fmodules-ts -std=c++26 std.C hello.C && ./a.out # after
Hello World!
It's great that this is so close to working!
> }
> 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);
> 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
>
>
