On Wed, 3 Jan 2024, Nathaniel Shead wrote:
> Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk?
>
> -- >8 --
>
> The attached testcase Patrick found in PR c++/112899 ICEs because it is
> attempting to write a variable initializer that is no longer in the
> static_aggregates map.
>
> The issue is that, for non-header modules, the loop in
> c_parse_final_cleanups prunes the static_aggregates list, which means
> that by the time we get to emitting module information those
> initialisers have been lost.
>
> However, we don't actually need to write non-trivial initialisers for
> non-header modules, because they've already been emitted as part of the
> module TU itself. Instead let's just only write the initializers from
> header modules (which skipped writing them in c_parse_final_cleanups).
Makes sense to me. It seems this may also fix PR103994 where we ICE
in the same spot when streaming out an initializer from the global
module fragment.
>
> gcc/cp/ChangeLog:
>
> * module.cc (trees_out::write_var_def): Only write initializers
> in header modules.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/modules/init-5_a.C: New test.
> * g++.dg/modules/init-5_b.C: New test.
>
> Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com>
> ---
> gcc/cp/module.cc | 3 ++-
> gcc/testsuite/g++.dg/modules/init-5_a.C | 9 +++++++++
> gcc/testsuite/g++.dg/modules/init-5_b.C | 10 ++++++++++
> 3 files changed, 21 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/g++.dg/modules/init-5_a.C
> create mode 100644 gcc/testsuite/g++.dg/modules/init-5_b.C
>
> diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
> index 14818131a70..82b61a2c2ad 100644
> --- a/gcc/cp/module.cc
> +++ b/gcc/cp/module.cc
> @@ -11707,7 +11707,8 @@ trees_out::write_var_def (tree decl)
> {
> tree dyn_init = NULL_TREE;
>
> - if (DECL_NONTRIVIALLY_INITIALIZED_P (decl))
> + /* We only need to write initializers in header modules. */
> + if (header_module_p () && DECL_NONTRIVIALLY_INITIALIZED_P (decl))
> {
> dyn_init = value_member (decl,
> CP_DECL_THREAD_LOCAL_P (decl)
> diff --git a/gcc/testsuite/g++.dg/modules/init-5_a.C
> b/gcc/testsuite/g++.dg/modules/init-5_a.C
> new file mode 100644
> index 00000000000..466b120b5a0
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/init-5_a.C
> @@ -0,0 +1,9 @@
> +// { dg-additional-options "-fmodules-ts" }
> +// { dg-module-cmi M }
> +
> +export module M;
> +
> +export struct A {
> + static int f() { return -1; }
> + static inline int x = f();
> +};
> diff --git a/gcc/testsuite/g++.dg/modules/init-5_b.C
> b/gcc/testsuite/g++.dg/modules/init-5_b.C
> new file mode 100644
> index 00000000000..40973cc6936
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/modules/init-5_b.C
> @@ -0,0 +1,10 @@
> +// { 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
>
>
