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c++, coroutines: Make and use a frame access helper.

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In the review of earlier patches it was suggested that we might make
use of finish_class_access_expr instead of doing a lookup for the
member and then a build_class_access_expr call.

finish_class_access_expr does a lot more work than we need and ends
up calling build_class_access_expr anyway.  So, instead, this patch
makes a new helper to do the lookup and build and uses that helper
everywhere except instances in the ramp function that we are going
to handle separately.

gcc/cp/ChangeLog:

	* coroutines.cc (coro_build_frame_access_expr): New.
	(transform_await_expr): Use coro_build_frame_access_expr.
	(transform_local_var_uses): Likewise.
	(build_actor_fn): Likewise.
	(build_destroy_fn): Likewise.
	(cp_coroutine_transform::build_ramp_function): Likewise.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>
This commit is contained in:
Iain Sandoe 2024-08-27 14:52:26 +01:00
parent b7e9f36108
commit 049a927c10
1 changed files with 44 additions and 47 deletions
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91
gcc/cp/coroutines.cc
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@ -1670,6 +1670,29 @@ coro_validate_builtin_call (tree call, tsubst_flags_t)
The complete bodies for the ramp, actor and destroy function are passed
back to finish_function for folding and gimplification. */
/* Helper to build a coroutine state frame access expression
CORO_FP is a frame pointer
MEMBER_ID is an identifier for a frame field
PRESERVE_REF is true, the expression returned will have REFERENCE_TYPE if
the MEMBER does.
COMPLAIN is passed to the underlying functions. */
static tree
coro_build_frame_access_expr (tree coro_ref, tree member_id, bool preserve_ref,
tsubst_flags_t complain)
{
gcc_checking_assert (INDIRECT_REF_P (coro_ref));
tree fr_type = TREE_TYPE (coro_ref);
tree mb = lookup_member (fr_type, member_id, /*protect=*/1, /*want_type=*/0,
complain);
if (!mb || mb == error_mark_node)
return error_mark_node;
tree expr
= build_class_member_access_expr (coro_ref, mb, NULL_TREE,
preserve_ref, complain);
return expr;
}
/* Helpers to build EXPR_STMT and void-cast EXPR_STMT, common ops. */
static tree
@ -2064,19 +2087,13 @@ transform_await_expr (tree await_expr, await_xform_data *xform)
We no longer need a [it had diagnostic value, maybe?]
We need to replace the e_proxy in the awr_call. */
tree coro_frame_type = TREE_TYPE (xform->actor_frame);
/* If we have a frame var for the awaitable, get a reference to it. */
proxy_replace data;
if (si->await_field_id)
{
tree as_m
= lookup_member (coro_frame_type, si->await_field_id,
/*protect=*/1, /*want_type=*/0, tf_warning_or_error);
tree as = build_class_member_access_expr (xform->actor_frame, as_m,
NULL_TREE, true,
tf_warning_or_error);
tree as
= coro_build_frame_access_expr (xform->actor_frame, si->await_field_id,
true, tf_warning_or_error);
/* Replace references to the instance proxy with the frame entry now
computed. */
data.from = TREE_OPERAND (await_expr, 1);
@ -2154,13 +2171,10 @@ transform_local_var_uses (tree *stmt, int *do_subtree, void *d)
known not-used. */
if (local_var.field_id == NULL_TREE)
continue; /* Wasn't used. */
tree fld_ref
= lookup_member (lvd->coro_frame_type, local_var.field_id,
/*protect=*/1, /*want_type=*/0,
tf_warning_or_error);
tree fld_idx = build3 (COMPONENT_REF, TREE_TYPE (lvar),
lvd->actor_frame, fld_ref, NULL_TREE);
tree fld_idx
= coro_build_frame_access_expr (lvd->actor_frame,
local_var.field_id, true,
tf_warning_or_error);
local_var.field_idx = fld_idx;
SET_DECL_VALUE_EXPR (lvar, fld_idx);
DECL_HAS_VALUE_EXPR_P (lvar) = true;
@ -2250,12 +2264,8 @@ build_actor_fn (location_t loc, tree coro_frame_type, tree actor, tree fnbody,
local_vars_transform xform_vars_data
= {actor, actor_frame, coro_frame_type, loc, local_var_uses};
cp_walk_tree (&fnbody, transform_local_var_uses, &xform_vars_data, NULL);
tree rat_field = lookup_member (coro_frame_type, coro_resume_index_id,
1, 0, tf_warning_or_error);
tree rat = build3 (COMPONENT_REF, short_unsigned_type_node, actor_frame,
rat_field, NULL_TREE);
tree rat = coro_build_frame_access_expr (actor_frame, coro_resume_index_id,
false, tf_warning_or_error);
tree ret_label
= create_named_label_with_ctx (loc, "actor.suspend.ret", actor);
@ -2345,10 +2355,8 @@ build_actor_fn (location_t loc, tree coro_frame_type, tree actor, tree fnbody,
add_stmt (r);
/* actor's coroutine 'self handle'. */
tree ash_m = lookup_member (coro_frame_type, coro_self_handle_id, 1,
0, tf_warning_or_error);
tree ash = build_class_member_access_expr (actor_frame, ash_m, NULL_TREE,
false, tf_warning_or_error);
tree ash = coro_build_frame_access_expr (actor_frame, coro_self_handle_id,
false, tf_warning_or_error);
/* So construct the self-handle from the frame address. */
tree hfa_m = get_coroutine_from_address (orig);
/* Should have been set earlier by coro_promise_type_found_p. */
@ -2391,11 +2399,9 @@ build_actor_fn (location_t loc, tree coro_frame_type, tree actor, tree fnbody,
/* Here deallocate the frame (if we allocated it), which we will have at
present. */
tree fnf_m
= lookup_member (coro_frame_type, coro_frame_needs_free_id, 1,
0, tf_warning_or_error);
tree fnf2_x = build_class_member_access_expr (actor_frame, fnf_m, NULL_TREE,
false, tf_warning_or_error);
tree fnf2_x
= coro_build_frame_access_expr (actor_frame, coro_frame_needs_free_id,
false, tf_warning_or_error);
tree need_free_if = begin_if_stmt ();
fnf2_x = build1 (CONVERT_EXPR, integer_type_node, fnf2_x);
@ -2403,11 +2409,9 @@ build_actor_fn (location_t loc, tree coro_frame_type, tree actor, tree fnbody,
finish_if_stmt_cond (cmp, need_free_if);
while (!param_dtor_list->is_empty ())
{
tree pid = param_dtor_list->pop ();
tree m = lookup_member (coro_frame_type, pid, 1, 0, tf_warning_or_error);
gcc_checking_assert (m);
tree a = build_class_member_access_expr (actor_frame, m, NULL_TREE,
false, tf_warning_or_error);
tree parm_id = param_dtor_list->pop ();
tree a = coro_build_frame_access_expr (actor_frame, parm_id, false,
tf_warning_or_error);
if (tree dtor = cxx_maybe_build_cleanup (a, tf_warning_or_error))
add_stmt (dtor);
}
@ -2504,11 +2508,8 @@ build_destroy_fn (location_t loc, tree coro_frame_type, tree destroy,
= cp_build_indirect_ref (loc, destr_fp, RO_UNARY_STAR,
tf_warning_or_error);
tree rat_field = lookup_member (coro_frame_type, coro_resume_index_id,
1, 0, tf_warning_or_error);
tree rat
= build_class_member_access_expr (destr_frame, rat_field, NULL_TREE,
/*reference*/false, tf_warning_or_error);
tree rat = coro_build_frame_access_expr (destr_frame, coro_resume_index_id,
false, tf_warning_or_error);
/* _resume_at |= 1 */
tree dstr_idx
@ -4836,13 +4837,9 @@ cp_coroutine_transform::build_ramp_function ()
{
bool existed;
param_info &parm = param_uses.get_or_insert (arg, &existed);
tree fld_ref = lookup_member (frame_type, parm.field_id,
/*protect=*/1, /*want_type=*/0,
tf_warning_or_error);
tree fld_idx
= build_class_member_access_expr (deref_fp, fld_ref, NULL_TREE,
false, tf_warning_or_error);
= coro_build_frame_access_expr (deref_fp, parm.field_id,
false, tf_warning_or_error);
/* Add this to the promise CTOR arguments list, accounting for
refs and special handling for method this ptr. */