On Fri, 25 Jul 2025, Nathaniel Shead wrote:
> Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk?
>
> -- >8 --
>
> I noticed that C++26 trivial relocation didn't work in modules yet, and
> there are a couple of other flags that seem potentially useful we
> weren't streaming. This streams those flags and adds a comment to
> cp-tree.h to help people remember about modules when adding more.
>
> As a drive-by improvement, update gcc_assert with gcc_checking_assert in
> lang_type_bools streaming.
LGTM
>
> gcc/cp/ChangeLog:
>
> * cp-tree.h (struct lang_type): Add comment mentioning modules.
> * module.cc (trees_out::lang_type_bools): Stream new flags, use
> gcc_checking_assert.
> (trees_in::lang_type_bools): Likewise.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/modules/class-11_a.H: New test.
> * g++.dg/modules/class-11_b.C: New test.
>
> Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com>
> ---
> gcc/cp/cp-tree.h | 4 ++-
> gcc/cp/module.cc | 22 ++++++++++++--
> gcc/testsuite/g++.dg/modules/class-11_a.H | 36 +++++++++++++++++++++++
> gcc/testsuite/g++.dg/modules/class-11_b.C | 15 ++++++++++
> 4 files changed, 73 insertions(+), 4 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/modules/class-11_a.H
> create mode 100644 gcc/testsuite/g++.dg/modules/class-11_b.C
>
> diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
> index 01112aa894e..22bb70136f5 100644
> --- a/gcc/cp/cp-tree.h
> +++ b/gcc/cp/cp-tree.h
> @@ -2508,7 +2508,9 @@ struct GTY(()) lang_type {
>
> /* When adding a flag here, consider whether or not it ought to
> apply to a template instance if it applies to the template. If
> - so, make sure to copy it in instantiate_class_template! */
> + so, make sure to copy it in instantiate_class_template!
> +
> + Also make sure new flags here are streamed in module.cc. */
>
> /* There are some bits left to fill out a 32-bit word. Keep track
> of this by updating the size of this bitfield whenever you add or
> diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
> index a551509ec0b..ed51837433e 100644
> --- a/gcc/cp/module.cc
> +++ b/gcc/cp/module.cc
> @@ -6157,7 +6157,7 @@ trees_out::lang_type_bools (tree t, bits_out& bits)
> WB (lang->declared_class);
> WB (lang->diamond_shaped);
> WB (lang->repeated_base);
> - gcc_assert (!lang->being_defined);
> + gcc_checking_assert (!lang->being_defined);
> // lang->debug_requested
> WB (lang->fields_readonly);
> WB (lang->ptrmemfunc_flag);
> @@ -6183,6 +6183,14 @@ trees_out::lang_type_bools (tree t, bits_out& bits)
> WB (lang->has_constexpr_ctor);
> WB (lang->unique_obj_representations);
> WB (lang->unique_obj_representations_set);
> + gcc_checking_assert (!lang->erroneous);
> + WB (lang->non_pod_aggregate);
> + WB (lang->non_aggregate_pod);
> + WB (lang->trivially_relocatable);
> + WB (lang->trivially_relocatable_computed);
> +
> + WB (lang->replaceable);
> + WB (lang->replaceable_computed);
> #undef WB
> }
>
> @@ -6227,8 +6235,8 @@ trees_in::lang_type_bools (tree t, bits_in& bits)
> RB (lang->declared_class);
> RB (lang->diamond_shaped);
> RB (lang->repeated_base);
> - gcc_assert (!lang->being_defined);
> - gcc_assert (!lang->debug_requested);
> + gcc_checking_assert (!lang->being_defined);
> + gcc_checking_assert (!lang->debug_requested);
> RB (lang->fields_readonly);
> RB (lang->ptrmemfunc_flag);
>
> @@ -6253,6 +6261,14 @@ trees_in::lang_type_bools (tree t, bits_in& bits)
> RB (lang->has_constexpr_ctor);
> RB (lang->unique_obj_representations);
> RB (lang->unique_obj_representations_set);
> + gcc_checking_assert (!lang->erroneous);
> + RB (lang->non_pod_aggregate);
> + RB (lang->non_aggregate_pod);
> + RB (lang->trivially_relocatable);
> + RB (lang->trivially_relocatable_computed);
> +
> + RB (lang->replaceable);
> + RB (lang->replaceable_computed);
> #undef RB
> return !get_overrun ();
> }
> diff --git a/gcc/testsuite/g++.dg/modules/class-11_a.H
> b/gcc/testsuite/g++.dg/modules/class-11_a.H
> new file mode 100644
> index 00000000000..b14a8adb1ed
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/class-11_a.H
> @@ -0,0 +1,36 @@
> +// Check for some additional lang_type flags that we'd missed.
> +// { dg-additional-options "-fmodule-header -fabi-version=21 -Wabi=15" }
> +// { dg-module-cmi {} }
> +
> +#if __cpp_trivial_relocatability < 202502L
> +#define trivially_relocatable_if_eligible __trivially_relocatable_if_eligible
> +#define replaceable_if_eligible __replaceable_if_eligible
> +#endif
> +
> +struct A trivially_relocatable_if_eligible { A(A&&); };
> +struct B replaceable_if_eligible { B(B&&); B& operator=(B&&); };
> +struct C {};
> +static_assert(__builtin_is_trivially_relocatable(C) &&
> __builtin_is_replaceable(C));
> +
> +
> +struct pr106381 {
> + long l;
> + char c = -1;
> +};
> +struct L1 : pr106381 {
> + char x; // { dg-warning "offset" "" { target c++14 } }
> +};
> +static_assert(sizeof(L1) == sizeof(pr106381));
> +
> +
> +struct pr120012 {
> + pr120012(const pr120012&) = default;
> + pr120012(pr120012&&) = default;
> + pr120012& operator=(pr120012&&) = default;
> + unsigned int a;
> + unsigned char b;
> +};
> +struct L2 : pr120012 {
> + unsigned char y; // { dg-warning "offset" "" { target c++20 } }
> +};
> +static_assert(sizeof(L2) > sizeof(pr120012));
> diff --git a/gcc/testsuite/g++.dg/modules/class-11_b.C
> b/gcc/testsuite/g++.dg/modules/class-11_b.C
> new file mode 100644
> index 00000000000..476cb63308f
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/class-11_b.C
> @@ -0,0 +1,15 @@
> +// { dg-additional-options "-fmodules -fabi-version=21 -Wabi=15" }
> +
> +import "class-11_a.H";
> +
> +static_assert(__builtin_is_trivially_relocatable(A));
> +static_assert(__builtin_is_replaceable(B));
> +static_assert(__builtin_is_trivially_relocatable(C) &&
> __builtin_is_replaceable(C));
> +
> +struct M1 : pr106381 {
> + char x; // { dg-warning "offset" "" { target c++14 } }
> +};
> +
> +struct M2 : pr120012 {
> + unsigned char y; // { dg-warning "offset" "" { target c++20 } }
> +};
> --
> 2.47.0
>
>
