> On 3 Sep 2021, at 14:39, Jason Merrill <ja...@redhat.com> wrote:
>
> On 9/1/21 6:54 AM, Iain Sandoe wrote:
>> This is an efficiency measure and repeats the pattern used for
>> other identifiers used in the coroutine implementation.
>> In support of debugging, the user might well need to look at some
>> of the variables that the implementation manipulates in lowering
>> the coroutines. The defines the identifiers for these and populates
>> them on demand (avoiding repeated identifier calls).
>> Contributory to debug support (PR 99215)
>> Signed-off-by: Iain Sandoe <i...@sandoe.co.uk>
>> gcc/cp/ChangeLog:
>> * coroutines.cc: Add identifiers for implementation
>> variables that we want to expose to debug.
>> (coro_init_identifiers): Initialize implementation names.
>> (coro_promise_type_found_p): Use pre-built identifiers.
>> (build_actor_fn): Likewise.
>> (build_destroy_fn): Likewise.
>> ---
>> gcc/cp/coroutines.cc | 32 ++++++++++++++++++++++++--------
>> 1 file changed, 24 insertions(+), 8 deletions(-)
>> diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
>> index 081e1a46c63..3b46aac4dc5 100644
>> --- a/gcc/cp/coroutines.cc
>> +++ b/gcc/cp/coroutines.cc
>> @@ -215,7 +215,17 @@ static GTY(()) tree coro_await_ready_identifier;
>> static GTY(()) tree coro_await_suspend_identifier;
>> static GTY(()) tree coro_await_resume_identifier;
>> -/* Create the identifiers used by the coroutines library interfaces. */
>> +/* Accessors for the coroutine frame state used by the implementation. */
>> +
>> +static GTY(()) tree coro_resume_fn_field;
>> +static GTY(()) tree coro_destroy_fn_field;
>> +static GTY(()) tree coro_promise_field;
>> +static GTY(()) tree coro_frame_needs_free_field;
>> +static GTY(()) tree coro_resume_index_field;
>> +static GTY(()) tree coro_self_handle_field;
>
> Since these are identifiers, not FIELD_DECLs, calling them *_field seems
> misleading.
>
>> +/* Create the identifiers used by the coroutines library interfaces and
>> + the implementation frame state. */
>> static void
>> coro_init_identifiers ()
>> @@ -241,6 +251,14 @@ coro_init_identifiers ()
>> coro_await_ready_identifier = get_identifier ("await_ready");
>> coro_await_suspend_identifier = get_identifier ("await_suspend");
>> coro_await_resume_identifier = get_identifier ("await_resume");
>> +
>> + /* Coroutine state frame field accessors. */
>> + coro_resume_fn_field = get_identifier ("_Coro_resume_fn");
>> + coro_destroy_fn_field = get_identifier ("_Coro_destroy_fn");
>> + coro_promise_field = get_identifier ("_Coro_promise");
>> + coro_frame_needs_free_field = get_identifier ("_Coro_frame_needs_free");
>> + coro_resume_index_field = get_identifier ("_Coro_resume_index");
>> + coro_self_handle_field = get_identifier ("_Coro_self_handle");
>> }
>> /* Trees we only need to set up once. */
>> @@ -513,12 +531,12 @@ coro_promise_type_found_p (tree fndecl, location_t loc)
>> /* Build a proxy for a handle to "self" as the param to
>> await_suspend() calls. */
>> coro_info->self_h_proxy
>> - = build_lang_decl (VAR_DECL, get_identifier ("_Coro_self_handle"),
>> + = build_lang_decl (VAR_DECL, coro_self_handle_field,
>> coro_info->handle_type);
>> /* Build a proxy for the promise so that we can perform lookups. */
>> coro_info->promise_proxy
>> - = build_lang_decl (VAR_DECL, get_identifier ("_Coro_promise"),
>> + = build_lang_decl (VAR_DECL, coro_promise_field,
>> coro_info->promise_type);
>> /* Note where we first saw a coroutine keyword. */
>> @@ -2198,8 +2216,7 @@ build_actor_fn (location_t loc, tree coro_frame_type,
>> tree actor, tree fnbody,
>> = {actor, actor_frame, coro_frame_type, loc, local_var_uses};
>> cp_walk_tree (&fnbody, transform_local_var_uses, &xform_vars_data, NULL);
>> - tree resume_idx_name = get_identifier ("_Coro_resume_index");
>> - tree rat_field = lookup_member (coro_frame_type, resume_idx_name, 1, 0,
>> + tree rat_field = lookup_member (coro_frame_type, coro_resume_index_field,
>> 1, 0,
>> tf_warning_or_error);
>> tree rat = build3 (COMPONENT_REF, short_unsigned_type_node, actor_frame,
>> rat_field, NULL_TREE);
>> @@ -2462,7 +2479,7 @@ build_actor_fn (location_t loc, tree coro_frame_type,
>> tree actor, tree fnbody,
>> /* We will need to know which resume point number should be encoded. */
>> tree res_idx_m
>> - = lookup_member (coro_frame_type, resume_idx_name,
>> + = lookup_member (coro_frame_type, coro_resume_index_field,
>> /*protect=*/1, /*want_type=*/0, tf_warning_or_error);
>> tree resume_pt_number
>> = build_class_member_access_expr (actor_frame, res_idx_m, NULL_TREE,
>> false,
>> @@ -2504,8 +2521,7 @@ build_destroy_fn (location_t loc, tree
>> coro_frame_type, tree destroy,
>> tree destr_frame = build1 (INDIRECT_REF, coro_frame_type, destr_fp);
>> - tree resume_idx_name = get_identifier ("_Coro_resume_index");
>> - tree rat_field = lookup_member (coro_frame_type, resume_idx_name, 1, 0,
>> + tree rat_field = lookup_member (coro_frame_type, coro_resume_index_field,
>> 1, 0,
>> tf_warning_or_error);
>> tree rat = build3 (COMPONENT_REF, short_unsigned_type_node, destr_frame,
>> rat_field, NULL_TREE);
