------
The standard describes a rewrite of the body of the user-authored
function (which wraps it in a try-catch block and provides the
initial and final suspend expressions). The exact arrangement of
this was still in flux right up until the WG21 meeting in Prague and
as a consequence was a bit of a moving target.
The net result was a fragmented implementation of the parts of
this rewrite which is now impeding progress in fixing other issues.
This patch collates the rewrite action into a single function and
carries this out earlier.
gcc/cp/ChangeLog:
* coroutines.cc (expand_one_await_expression): Remove
code dealing with initial suspend.
(build_actor_fn): Remove code special-casing initial
and final suspend. Handle the final suspend and marking
of the coroutine as done.
(coro_rewrite_function_body): New.
(bind_expr_find_in_subtree): Remove.
(coro_body_contains_bind_expr_p): Remove.
(morph_fn_to_coro): Split the rewrite of the original
function into coro_rewrite_function_body and call it.
---
gcc/cp/coroutines.cc | 534 +++++++++++++++++--------------------------
1 file changed, 208 insertions(+), 326 deletions(-)
diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
index 54f9cb3b4e4..8e0f0e09b56 100644
--- a/gcc/cp/coroutines.cc
+++ b/gcc/cp/coroutines.cc
@@ -1573,8 +1573,6 @@ expand_one_await_expression (tree *stmt, tree
*await_expr, void *d)
tree awaiter_calls = TREE_OPERAND (saved_co_await, 3);
tree source = TREE_OPERAND (saved_co_await, 4);
- bool is_initial =
- (source && TREE_INT_CST_LOW (source) == (int) INITIAL_SUSPEND_POINT);
bool is_final = (source
&& TREE_INT_CST_LOW (source) == (int) FINAL_SUSPEND_POINT);
bool needs_dtor = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (var));
@@ -1724,16 +1722,6 @@ expand_one_await_expression (tree *stmt, tree
*await_expr, void *d)
resume_label = build_stmt (loc, LABEL_EXPR, resume_label);
append_to_statement_list (resume_label, &stmt_list);
- if (is_initial)
- {
- /* Note that we are about to execute the await_resume() for the initial
- await expression. */
- r = build2_loc (loc, MODIFY_EXPR, boolean_type_node, data->i_a_r_c,
- boolean_true_node);
- r = coro_build_cvt_void_expr_stmt (r, loc);
- append_to_statement_list (r, &stmt_list);
- }
-
/* This will produce the value (if one is provided) from the co_await
expression. */
tree resume_call = TREE_VEC_ELT (awaiter_calls, 2); /* await_resume(). */
@@ -2102,19 +2090,16 @@ static void
build_actor_fn (location_t loc, tree coro_frame_type, tree actor, tree fnbody,
tree orig, hash_map<tree, param_info> *param_uses,
hash_map<tree, local_var_info> *local_var_uses,
- vec<tree, va_gc> *param_dtor_list, tree initial_await,
- tree final_await, unsigned body_count, tree frame_size)
+ vec<tree, va_gc> *param_dtor_list,
+ tree fs_label, tree resume_fn_field,
+ unsigned body_count, tree frame_size)
{
verify_stmt_tree (fnbody);
/* Some things we inherit from the original function. */
- tree coro_frame_ptr = build_pointer_type (coro_frame_type);
tree handle_type = get_coroutine_handle_type (orig);
tree self_h_proxy = get_coroutine_self_handle_proxy (orig);
tree promise_type = get_coroutine_promise_type (orig);
tree promise_proxy = get_coroutine_promise_proxy (orig);
- tree act_des_fn_type
- = build_function_type_list (void_type_node, coro_frame_ptr, NULL_TREE);
- tree act_des_fn_ptr = build_pointer_type (act_des_fn_type);
/* One param, the coro frame pointer. */
tree actor_fp = DECL_ARGUMENTS (actor);
@@ -2145,21 +2130,15 @@ build_actor_fn (location_t loc, tree coro_frame_type,
tree actor, tree fnbody,
DECL_CONTEXT (continuation) = actor;
BIND_EXPR_VARS (actor_bind) = continuation;
- /* Update the block associated with the outer scope of the orig fn. */
+ /* Link in the block associated with the outer scope of the re-written
+ function body. */
tree first = expr_first (fnbody);
- if (first && TREE_CODE (first) == BIND_EXPR)
- {
- /* We will discard this, since it's connected to the original scope
- nest. */
- tree block = BIND_EXPR_BLOCK (first);
- if (block) /* For this to be missing is probably a bug. */
- {
- gcc_assert (BLOCK_SUPERCONTEXT (block) == NULL_TREE);
- gcc_assert (BLOCK_CHAIN (block) == NULL_TREE);
- BLOCK_SUPERCONTEXT (block) = top_block;
- BLOCK_SUBBLOCKS (top_block) = block;
- }
- }
+ gcc_checking_assert (first && TREE_CODE (first) == BIND_EXPR);
+ tree block = BIND_EXPR_BLOCK (first);
+ gcc_checking_assert (BLOCK_SUPERCONTEXT (block) == NULL_TREE);
+ gcc_checking_assert (BLOCK_CHAIN (block) == NULL_TREE);
+ BLOCK_SUPERCONTEXT (block) = top_block;
+ BLOCK_SUBBLOCKS (top_block) = block;
add_stmt (actor_bind);
tree actor_body = push_stmt_list ();
@@ -2326,55 +2305,19 @@ build_actor_fn (location_t loc, tree coro_frame_type,
tree actor, tree fnbody,
await_xform_data xform
= {actor, actor_frame, promise_proxy, ap, self_h_proxy, ash};
- /* Get a reference to the initial suspend var in the frame. */
- transform_await_expr (initial_await, &xform);
- tree initial_await_stmt = coro_build_expr_stmt (initial_await, loc);
-
- /* co_return branches to the final_suspend label, so declare that now. */
- tree fs_label = create_named_label_with_ctx (loc, "final.suspend", actor);
-
/* Expand co_returns in the saved function body */
fnbody = expand_co_returns (&fnbody, promise_proxy, ap, fs_label);
- /* Specific behaviour to treat exceptions thrown by the await_resume ()
- of the initial suspend expression. In order to implement this, we
- need to treat the initial_suspend expression as if it were part of the
- user-authored function body. This only applies if exceptions are
- enabled. */
- if (flag_exceptions)
- {
- tree outer = fnbody;
- if (TREE_CODE (outer) == BIND_EXPR)
- outer = BIND_EXPR_BODY (outer);
- gcc_checking_assert (TREE_CODE (outer) == TRY_BLOCK);
- tree sl = TRY_STMTS (outer);
- if (TREE_CODE (sl) == STATEMENT_LIST)
- {
- tree_stmt_iterator si = tsi_start (sl);
- tsi_link_before (&si, initial_await_stmt, TSI_NEW_STMT);
- }
- else
- {
- tree new_try = NULL_TREE;
- append_to_statement_list (initial_await_stmt, &new_try);
- append_to_statement_list (sl, &new_try);
- TRY_STMTS (outer) = new_try;
- }
- }
- else
- add_stmt (initial_await_stmt);
-
/* Transform the await expressions in the function body. Only do each
await tree once! */
hash_set<tree> pset;
cp_walk_tree (&fnbody, transform_await_wrapper, &xform, &pset);
- /* Add in our function body with the co_returns rewritten to final form. */
- add_stmt (fnbody);
-
- /* Final suspend starts here. */
- r = build_stmt (loc, LABEL_EXPR, fs_label);
- add_stmt (r);
+ /* Now replace the promise proxy with its real value. */
+ proxy_replace p_data;
+ p_data.from = promise_proxy;
+ p_data.to = ap;
+ cp_walk_tree (&fnbody, replace_proxy, &p_data, NULL);
/* Set the actor pointer to null, so that 'done' will work.
Resume from here is UB anyway - although a 'ready' await will
@@ -2384,15 +2327,12 @@ build_actor_fn (location_t loc, tree coro_frame_type,
tree actor, tree fnbody,
/*protect=*/1, /*want_type=*/0, tf_warning_or_error);
tree res_x = build_class_member_access_expr (actor_frame, resume_m,
NULL_TREE,
false, tf_warning_or_error);
- r = build1 (CONVERT_EXPR, act_des_fn_ptr, integer_zero_node);
- r = build2 (INIT_EXPR, act_des_fn_ptr, res_x, r);
- r = coro_build_cvt_void_expr_stmt (r, loc);
- add_stmt (r);
+ p_data.from = resume_fn_field;
+ p_data.to = res_x;
+ cp_walk_tree (&fnbody, replace_proxy, &p_data, NULL);
- /* Get a reference to the final suspend var in the frame. */
- transform_await_expr (final_await, &xform);
- r = coro_build_expr_stmt (final_await, loc);
- add_stmt (r);
+ /* Add in our function body with the co_returns rewritten to final form. */
+ add_stmt (fnbody);
/* now do the tail of the function. */
tree del_promise_label
@@ -2559,20 +2499,10 @@ build_actor_fn (location_t loc, tree coro_frame_type,
tree actor, tree fnbody,
= build_class_member_access_expr (actor_frame, res_idx_m, NULL_TREE,
false,
tf_warning_or_error);
- /* Boolean value to flag that the initial suspend expression's
- await_resume () has been called, and therefore we are in the user's
- function body for the purposes of handing exceptions. */
- tree i_a_r_c_m
- = lookup_member (coro_frame_type, get_identifier ("__i_a_r_c"),
- /*protect=*/1, /*want_type=*/0, tf_warning_or_error);
- tree i_a_r_c
- = build_class_member_access_expr (actor_frame, i_a_r_c_m, NULL_TREE,
- false, tf_warning_or_error);
-
/* We've now rewritten the tree and added the initial and final
co_awaits. Now pass over the tree and expand the co_awaits. */
- coro_aw_data data = {actor, actor_fp, resume_pt_number, i_a_r_c,
+ coro_aw_data data = {actor, actor_fp, resume_pt_number, NULL_TREE,
ash, del_promise_label, ret_label,
continue_label, continuation, 2};
cp_walk_tree (&actor_body, await_statement_expander, &data, NULL);
@@ -3641,23 +3571,165 @@ act_des_fn (tree orig, tree fn_type, tree
coro_frame_ptr, const char* name)
return fn;
}
-/* Return a bind expression if we see one, else NULL_TREE. */
+/* Re-write the body as per [dcl.fct.def.coroutine] / 5. */
+
static tree
-bind_expr_find_in_subtree (tree *stmt, int *, void *)
+coro_rewrite_function_body (location_t fn_start, tree fnbody,
+ tree orig, tree resume_fn_ptr_type,
+ tree& resume_fn_field, tree& fs_label)
{
- if (TREE_CODE (*stmt) == BIND_EXPR)
- return *stmt;
- return NULL_TREE;
-}
+ /* This will be our new outer scope. */
+ tree update_body = build3 (BIND_EXPR, void_type_node, NULL, NULL, NULL);
+ tree top_block = make_node (BLOCK);
+ BIND_EXPR_BLOCK (update_body) = top_block;
+ BIND_EXPR_BODY (update_body) = push_stmt_list ();
-/* Return the first bind expression that the sub-tree given by STMT
- contains. */
+ /* If the function has a top level bind expression, then connect that
+ after first making sure we give it a new block. */
+ tree first = expr_first (fnbody);
+ if (first && TREE_CODE (first) == BIND_EXPR)
+ {
+ tree block = BIND_EXPR_BLOCK (first);
+ gcc_checking_assert (block);
+ gcc_checking_assert (BLOCK_SUPERCONTEXT (block) == NULL_TREE);
+ gcc_checking_assert (BLOCK_CHAIN (block) == NULL_TREE);
+ /* Replace the top block to avoid issues with locations for args
+ appearing to be in a non-existent place. */
+ tree replace_blk = make_node (BLOCK);
+ BLOCK_VARS (replace_blk) = BLOCK_VARS (block);
+ BLOCK_SUBBLOCKS (replace_blk) = BLOCK_SUBBLOCKS (block);
+ for (tree b = BLOCK_SUBBLOCKS (replace_blk); b; b = BLOCK_CHAIN (b))
+ BLOCK_SUPERCONTEXT (b) = replace_blk;
+ BIND_EXPR_BLOCK (first) = replace_blk;
+ /* The top block has one child, so far, and we have now got a
+ superblock. */
+ BLOCK_SUPERCONTEXT (block) = top_block;
+ BLOCK_SUBBLOCKS (top_block) = block;
+ }
-static tree
-coro_body_contains_bind_expr_p (tree *stmt)
-{
- hash_set<tree> visited;
- return cp_walk_tree (stmt, bind_expr_find_in_subtree, NULL, &visited);
+ /* Wrap the function body in a try {} catch (...) {} block, if exceptions
+ are enabled. */
+ tree promise = get_coroutine_promise_proxy (orig);
+ tree var_list = NULL_TREE;
+ tree initial_await = build_init_or_final_await (fn_start, false);
+
+ /* [stmt.return.coroutine] / 3
+ If p.return_void() is a valid expression, flowing off the end of a
+ coroutine is equivalent to a co_return with no operand; otherwise
+ flowing off the end of a coroutine results in undefined behavior. */
+ tree return_void
+ = get_coroutine_return_void_expr (current_function_decl, fn_start, false);
+
+ if (flag_exceptions)
+ {
+ /* Build promise.unhandled_exception(); */
+ tree ueh
+ = coro_build_promise_expression (current_function_decl, promise,
+ coro_unhandled_exception_identifier,
+ fn_start, NULL, /*musthave=*/true);
+ /* Create and initialize the initial-await-resume-called variable per
+ [dcl.fct.def.coroutine] / 5.3. */
+ tree i_a_r_c = build_lang_decl (VAR_DECL, get_identifier ("__i_a_r_c"),
+ boolean_type_node);
+ DECL_ARTIFICIAL (i_a_r_c) = true;
+ DECL_CHAIN (i_a_r_c) = var_list;
+ var_list = i_a_r_c;
+ DECL_INITIAL (i_a_r_c) = boolean_false_node;
+ add_decl_expr (i_a_r_c);
+ /* Start the try-catch. */
+ tree tcb = build_stmt (fn_start, TRY_BLOCK, NULL_TREE, NULL_TREE);
+ add_stmt (tcb);
+ TRY_STMTS (tcb) = push_stmt_list ();
+ if (initial_await != error_mark_node)
+ {
+ /* Build a compound expression that sets the
+ initial-await-resume-called variable true and then calls the
+ initial suspend expression await resume. */
+ tree vec = TREE_OPERAND (initial_await, 3);
+ tree aw_r = TREE_VEC_ELT (vec, 2);
+ tree update = build2 (MODIFY_EXPR, boolean_type_node, i_a_r_c,
+ boolean_true_node);
+ aw_r = cp_build_compound_expr (update, aw_r, tf_warning_or_error);
+ TREE_VEC_ELT (vec, 2) = aw_r;
+ }
+ /* Add the initial await to the start of the user-authored function. */
+ finish_expr_stmt (initial_await);
+ /* Append the original function body. */
+ add_stmt (fnbody);
+ if (return_void)
+ add_stmt (return_void);
+ TRY_STMTS (tcb) = pop_stmt_list (TRY_STMTS (tcb));
+ TRY_HANDLERS (tcb) = push_stmt_list ();
+ /* Mimic what the parser does for the catch. */
+ tree handler = begin_handler ();
+ finish_handler_parms (NULL_TREE, handler); /* catch (...) */
+
+ /* Get the initial await resume called value. */
+ tree not_iarc_if = begin_if_stmt ();
+ tree not_iarc = build1_loc (fn_start, TRUTH_NOT_EXPR,
+ boolean_type_node, i_a_r_c);
+ finish_if_stmt_cond (not_iarc, not_iarc_if);
+ /* If the initial await resume called value is false, rethrow... */
+ tree rethrow = build_throw (fn_start, NULL_TREE);
+ TREE_NO_WARNING (rethrow) = true;
+ finish_expr_stmt (rethrow);
+ finish_then_clause (not_iarc_if);
+ tree iarc_scope = IF_SCOPE (not_iarc_if);
+ IF_SCOPE (not_iarc_if) = NULL;
+ not_iarc_if = do_poplevel (iarc_scope);
+ add_stmt (not_iarc_if);
+ /* ... else call the promise unhandled exception method. */
+ ueh = maybe_cleanup_point_expr_void (ueh);
+ add_stmt (ueh);
+ finish_handler (handler);
+ TRY_HANDLERS (tcb) = pop_stmt_list (TRY_HANDLERS (tcb));
+ }
+ else
+ {
+ if (pedantic)
+ {
+ /* We still try to look for the promise method and warn if it's not
+ present. */
+ tree ueh_meth
+ = lookup_promise_method (orig, coro_unhandled_exception_identifier,
+ fn_start, /*musthave=*/false);
+ if (!ueh_meth || ueh_meth == error_mark_node)
+ warning_at (fn_start, 0, "no member named %qE in %qT",
+ coro_unhandled_exception_identifier,
+ get_coroutine_promise_type (orig));
+ }
+ /* Else we don't check and don't care if the method is missing..
+ just add the initial suspend, function and return. */
+ finish_expr_stmt (initial_await);
+ /* Append the original function body. */
+ add_stmt (fnbody);
+ if (return_void)
+ add_stmt (return_void);
+ }
+
+ /* co_return branches to the final_suspend label, so declare that now. */
+ fs_label
+ = create_named_label_with_ctx (fn_start, "final.suspend", NULL_TREE);
+ add_stmt (build_stmt (fn_start, LABEL_EXPR, fs_label));
+
+ /* Before entering the final suspend point, we signal that this point has
+ been reached by setting the resume function pointer to zero (this is
+ what the 'done()' builtin tests) as per the current ABI. */
+ resume_fn_field
+ = build_lang_decl (VAR_DECL, get_identifier ("resume.fn.ptr.proxy"),
+ resume_fn_ptr_type);
+ DECL_ARTIFICIAL (resume_fn_field) = true;
+ tree zero_resume
+ = build1 (CONVERT_EXPR, resume_fn_ptr_type, integer_zero_node);
+ zero_resume
+ = build2 (INIT_EXPR, resume_fn_ptr_type, resume_fn_field, zero_resume);
+ finish_expr_stmt (zero_resume);
+ finish_expr_stmt (build_init_or_final_await (fn_start, true));
+ BIND_EXPR_BODY (update_body) = pop_stmt_list (BIND_EXPR_BODY (update_body));
+ BIND_EXPR_VARS (update_body) = nreverse (var_list);
+ BLOCK_VARS (top_block) = BIND_EXPR_VARS (update_body);
+
+ return update_body;
}
/* Here we:
@@ -3734,55 +3806,32 @@ morph_fn_to_coro (tree orig, tree *resumer, tree
*destroyer)
return false;
}
- /* So, we've tied off the original body. Now start the replacement.
+ /* So, we've tied off the original user-authored body in fn_body.
+
+ Start the replacement synthesized ramp body as newbody.
If we encounter a fatal error we might return a now-empty body.
- TODO: determine if it would help to restore the original.
- determine if looking for more errors in coro_function_valid_p()
- and stashing types is a better solution. */
+
+ Note, the returned ramp body is not 'popped', to be compatible with
+ the way that decl.c handles regular functions, the scope pop is done
+ in the caller. */
tree newbody = push_stmt_list ();
DECL_SAVED_TREE (orig) = newbody;
/* If our original body is noexcept, then that's what we apply to our
- generated functions. Remember that we're NOEXCEPT and fish out the
- contained list (we tied off to the top level already). */
+ generated ramp, transfer any MUST_NOT_THOW_EXPR to that. */
bool is_noexcept = TREE_CODE (body_start) == MUST_NOT_THROW_EXPR;
if (is_noexcept)
{
- /* Simplified abstract from begin_eh_spec_block, since we already
- know the outcome. */
- fnbody = TREE_OPERAND (body_start, 0); /* Stash the original... */
- add_stmt (body_start); /* ... and start the new. */
+ /* The function body we will continue with is the single operand to
+ the must-not-throw. */
+ fnbody = TREE_OPERAND (body_start, 0);
+ /* Transfer the must-not-throw to the ramp body. */
+ add_stmt (body_start);
+ /* Re-start the ramp as must-not-throw. */
TREE_OPERAND (body_start, 0) = push_stmt_list ();
}
- /* We can be presented with a function that currently has no outer bind
- expression. We will insert bind scopes in expanding await expressions,
- and therefore need a top level to the tree, so synthesize an outer bind
- expression and scope. */
- tree check_bind = expr_first (fnbody);
- if (check_bind && TREE_CODE (check_bind) != BIND_EXPR)
- {
- tree update_body = build3 (BIND_EXPR, void_type_node, NULL, NULL, NULL);
- tree blk = make_node (BLOCK);
- gcc_checking_assert (!coro_body_contains_bind_expr_p (&fnbody));
- BIND_EXPR_BLOCK (update_body) = blk;
- if (TREE_CODE (fnbody) == STATEMENT_LIST)
- BIND_EXPR_BODY (update_body) = fnbody;
- else
- {
- tree tlist = NULL_TREE;
- append_to_statement_list_force (fnbody, &tlist);
- TREE_SIDE_EFFECTS (tlist) = TREE_SIDE_EFFECTS (fnbody);
- BIND_EXPR_BODY (update_body) = tlist;
- }
- tree new_body_list = NULL_TREE;
- TREE_SIDE_EFFECTS (update_body) = true;
- append_to_statement_list (update_body, &new_body_list);
- TREE_SIDE_EFFECTS (new_body_list) = true;
- fnbody = new_body_list;
- }
-
/* Create the coro frame type, as far as it can be known at this stage.
1. Types we already know. */
@@ -3792,35 +3841,6 @@ morph_fn_to_coro (tree orig, tree *resumer, tree *destroyer)
/* 2. Types we need to define or look up. */
- /* We need to know, and inspect, each suspend point in the function
- in several places. It's convenient to place this map out of line
- since it's used from tree walk callbacks. */
- suspend_points = new hash_map<tree, suspend_point_info>;
-
- /* Initial and final suspend types are special in that the co_awaits for
- them are synthetic. We need to find the type for each awaiter from
- the coroutine promise. */
- tree initial_await = build_init_or_final_await (fn_start, false);
- if (initial_await == error_mark_node)
- {
- /* Suppress warnings about the missing return value. */
- TREE_NO_WARNING (orig) = true;
- return false;
- }
- /* The type of the frame var for this is the type of its temp proxy. */
- tree initial_suspend_type = TREE_TYPE (TREE_OPERAND (initial_await, 1));
-
- tree final_await = build_init_or_final_await (fn_start, true);
- if (final_await == error_mark_node)
- {
- /* Suppress warnings about the missing return value. */
- TREE_NO_WARNING (orig) = true;
- return false;
- }
-
- /* The type of the frame var for this is the type of its temp proxy. */
- tree final_suspend_type = TREE_TYPE (TREE_OPERAND (final_await, 1));
-
tree fr_name = get_fn_local_identifier (orig, "frame");
tree coro_frame_type = xref_tag (record_type, fr_name, ts_current, false);
DECL_CONTEXT (TYPE_NAME (coro_frame_type)) = current_scope ();
@@ -3833,20 +3853,27 @@ morph_fn_to_coro (tree orig, tree *resumer, tree
*destroyer)
tree actor = act_des_fn (orig, act_des_fn_type, coro_frame_ptr, "actor");
tree destroy = act_des_fn (orig, act_des_fn_type, coro_frame_ptr,
"destroy");
+ /* Construct the wrapped function body; we will analyze this to determine
+ the requirements for the coroutine frame. */
+
+ tree resume_fn_field = NULL_TREE;
+ tree fs_label = NULL_TREE;
+ fnbody = coro_rewrite_function_body (fn_start, fnbody, orig, act_des_fn_ptr,
+ resume_fn_field, fs_label);
/* Build our dummy coro frame layout. */
coro_frame_type = begin_class_definition (coro_frame_type);
tree field_list = NULL_TREE;
tree resume_name
- = coro_make_frame_entry (&field_list, "__resume", act_des_fn_ptr,
fn_start);
- tree destroy_name = coro_make_frame_entry (&field_list, "__destroy",
- act_des_fn_ptr, fn_start);
+ = coro_make_frame_entry (&field_list, "__resume",
+ act_des_fn_ptr, fn_start);
+ tree destroy_name
+ = coro_make_frame_entry (&field_list, "__destroy",
+ act_des_fn_ptr, fn_start);
tree promise_name
= coro_make_frame_entry (&field_list, "__p", promise_type, fn_start);
tree fnf_name = coro_make_frame_entry (&field_list, "__frame_needs_free",
boolean_type_node, fn_start);
- tree iarc_name = coro_make_frame_entry (&field_list, "__i_a_r_c",
- boolean_type_node, fn_start);
tree resume_idx_name
= coro_make_frame_entry (&field_list, "__resume_at",
short_unsigned_type_node, fn_start);
@@ -3928,11 +3955,10 @@ morph_fn_to_coro (tree orig, tree *resumer, tree
*destroyer)
cp_walk_tree (&fnbody, register_param_uses, ¶m_data, NULL);
}
- /* Initial suspend is mandated. */
- tree init_susp_name = coro_make_frame_entry (&field_list, "__aw_s.is",
- initial_suspend_type, fn_start);
-
- register_await_info (initial_await, initial_suspend_type, init_susp_name);
+ /* We need to know, and inspect, each suspend point in the function
+ in several places. It's convenient to place this map out of line
+ since it's used from tree walk callbacks. */
+ suspend_points = new hash_map<tree, suspend_point_info>;
/* Now insert the data for any body await points, at this time we also need
to promote any temporaries that are captured by reference (to regular
@@ -3945,12 +3971,6 @@ morph_fn_to_coro (tree orig, tree *resumer, tree
*destroyer)
body_aw_points.to_replace = make_tree_vector ();
cp_walk_tree (&fnbody, await_statement_walker, &body_aw_points, NULL);
- /* Final suspend is mandated. */
- tree fin_susp_name = coro_make_frame_entry (&field_list, "__aw_s.fs",
- final_suspend_type, fn_start);
-
- register_await_info (final_await, final_suspend_type, fin_susp_name);
-
/* 4. Now make space for local vars, this is conservative again, and we
would expect to delete unused entries later. */
hash_map<tree, local_var_info> local_var_uses;
@@ -4455,17 +4475,6 @@ morph_fn_to_coro (tree orig, tree *resumer, tree
*destroyer)
r = coro_build_cvt_void_expr_stmt (r, fn_start);
add_stmt (r);
- /* Initialize 'initial-await-resume-called' as per
- [dcl.fct.def.coroutine] / 5.3 */
- tree i_a_r_c_m
- = lookup_member (coro_frame_type, iarc_name, 1, 0, tf_warning_or_error);
- tree i_a_r_c = build_class_member_access_expr (deref_fp, i_a_r_c_m,
- NULL_TREE, false,
- tf_warning_or_error);
- r = build2 (INIT_EXPR, boolean_type_node, i_a_r_c, boolean_false_node);
- r = coro_build_cvt_void_expr_stmt (r, fn_start);
- add_stmt (r);
-
/* So .. call the actor .. */
r = build_call_expr_loc (fn_start, actor, 1, coro_fp);
r = maybe_cleanup_point_expr_void (r);
@@ -4535,133 +4544,6 @@ morph_fn_to_coro (tree orig, tree *resumer, tree
*destroyer)
BIND_EXPR_BODY (ramp_bind) = pop_stmt_list (ramp_body);
TREE_SIDE_EFFECTS (ramp_bind) = true;
- /* We know the "real" promise and have a frame layout with a slot for each
- suspend point, so we can build an actor function (which contains the
- functionality for both 'resume' and 'destroy').
-
- wrap the function body in a try {} catch (...) {} block, if exceptions
- are enabled. */
-
- /* First make a new block for the body - that will be embedded in the
- re-written function. */
- tree first = expr_first (fnbody);
- bool orig_fn_has_outer_bind = false;
- tree replace_blk = NULL_TREE;
- if (first && TREE_CODE (first) == BIND_EXPR)
- {
- orig_fn_has_outer_bind = true;
- tree block = BIND_EXPR_BLOCK (first);
- replace_blk = make_node (BLOCK);
- if (block) /* missing block is probably an error. */
- {
- gcc_assert (BLOCK_SUPERCONTEXT (block) == NULL_TREE);
- gcc_assert (BLOCK_CHAIN (block) == NULL_TREE);
- BLOCK_VARS (replace_blk) = BLOCK_VARS (block);
- BLOCK_SUBBLOCKS (replace_blk) = BLOCK_SUBBLOCKS (block);
- for (tree b = BLOCK_SUBBLOCKS (replace_blk); b; b = BLOCK_CHAIN (b))
- BLOCK_SUPERCONTEXT (b) = replace_blk;
- }
- BIND_EXPR_BLOCK (first) = replace_blk;
- }
-
- /* actor's version of the promise. */
- tree actor_frame = build1_loc (fn_start, INDIRECT_REF, coro_frame_type,
- DECL_ARGUMENTS (actor));
- tree ap_m = lookup_member (coro_frame_type, get_identifier ("__p"), 1, 0,
- tf_warning_or_error);
- tree ap = build_class_member_access_expr (actor_frame, ap_m, NULL_TREE,
- false, tf_warning_or_error);
-
- /* Now we've built the promise etc, process fnbody for co_returns.
- We want the call to return_void () below and it has no params so
- we can create it once here.
- Calls to return_value () will have to be checked and created as
- required. */
-
- tree return_void
- = coro_build_promise_expression (current_function_decl, ap,
- coro_return_void_identifier,
- fn_start, NULL, /*musthave=*/false);
-
- /* [stmt.return.coroutine] (2.2 : 3) if p.return_void() is a valid
- expression, flowing off the end of a coroutine is equivalent to
- co_return; otherwise UB.
- We just inject the call to p.return_void() here, and fall through to
- the final_suspend: label (eliding the goto). If the function body has
- a co_return, then this statement will be unreachable and DCEd. */
- if (return_void != NULL_TREE)
- {
- tree append = push_stmt_list ();
- add_stmt (fnbody);
- add_stmt (return_void);
- fnbody = pop_stmt_list(append);
- }
-
- if (flag_exceptions)
- {
- tree ueh
- = coro_build_promise_expression (current_function_decl, ap,
- coro_unhandled_exception_identifier,
- fn_start, NULL, /*musthave=*/true);
-
- /* The try block is just the original function, there's no real
- need to call any function to do this. */
- fnbody = build_stmt (fn_start, TRY_BLOCK, fnbody, NULL_TREE);
- TRY_HANDLERS (fnbody) = push_stmt_list ();
- /* Mimic what the parser does for the catch. */
- tree handler = begin_handler ();
- finish_handler_parms (NULL_TREE, handler); /* catch (...) */
-
- /* Get the initial await resume called value. */
- tree i_a_r_c = build_class_member_access_expr (actor_frame, i_a_r_c_m,
- NULL_TREE, false,
- tf_warning_or_error);
- tree not_iarc_if = begin_if_stmt ();
- tree not_iarc = build1_loc (fn_start, TRUTH_NOT_EXPR,
- boolean_type_node, i_a_r_c);
- finish_if_stmt_cond (not_iarc, not_iarc_if);
- /* If the initial await resume called value is false, rethrow... */
- tree rethrow = build_throw (fn_start, NULL_TREE);
- TREE_NO_WARNING (rethrow) = true;
- finish_expr_stmt (rethrow);
- finish_then_clause (not_iarc_if);
- tree iarc_scope = IF_SCOPE (not_iarc_if);
- IF_SCOPE (not_iarc_if) = NULL;
- not_iarc_if = do_poplevel (iarc_scope);
- add_stmt (not_iarc_if);
- /* ... else call the promise unhandled exception method. */
- ueh = maybe_cleanup_point_expr_void (ueh);
- add_stmt (ueh);
- finish_handler (handler);
- TRY_HANDLERS (fnbody) = pop_stmt_list (TRY_HANDLERS (fnbody));
- /* If the function starts with a BIND_EXPR, then we need to create
- one here to contain the try-catch and to link up the scopes. */
- if (orig_fn_has_outer_bind)
- {
- fnbody = build3 (BIND_EXPR, void_type_node, NULL, fnbody, NULL);
- /* Make and connect the scope blocks. */
- tree tcb_block = make_node (BLOCK);
- /* .. and connect it here. */
- BLOCK_SUPERCONTEXT (replace_blk) = tcb_block;
- BLOCK_SUBBLOCKS (tcb_block) = replace_blk;
- BIND_EXPR_BLOCK (fnbody) = tcb_block;
- TREE_SIDE_EFFECTS (fnbody) = true;
- }
- }
- else if (pedantic)
- {
- /* We still try to look for the promise method and warn if it's not
- present. */
- tree ueh_meth
- = lookup_promise_method (orig, coro_unhandled_exception_identifier,
- fn_start, /*musthave=*/false);
- if (!ueh_meth || ueh_meth == error_mark_node)
- warning_at (fn_start, 0, "no member named %qE in %qT",
- coro_unhandled_exception_identifier,
- get_coroutine_promise_type (orig));
- }
- /* Else we don't check and don't care if the method is missing. */
-
/* Start to build the final functions.
We push_deferring_access_checks to avoid these routines being seen as
@@ -4671,7 +4553,7 @@ morph_fn_to_coro (tree orig, tree *resumer, tree
*destroyer)
/* Build the actor... */
build_actor_fn (fn_start, coro_frame_type, actor, fnbody, orig, param_uses,
- &local_var_uses, param_dtor_list, initial_await, final_await,
+ &local_var_uses, param_dtor_list, fs_label, resume_fn_field,
body_aw_points.await_number, frame_size);
/* Destroyer ... */
