Line data Source code
1 : /* coroutine-specific state, expansions and tests.
2 :
3 : Copyright (C) 2018-2026 Free Software Foundation, Inc.
4 :
5 : Contributed by Iain Sandoe <iain@sandoe.co.uk> under contract to Facebook.
6 :
7 : This file is part of GCC.
8 :
9 : GCC is free software; you can redistribute it and/or modify it under
10 : the terms of the GNU General Public License as published by the Free
11 : Software Foundation; either version 3, or (at your option) any later
12 : version.
13 :
14 : GCC is distributed in the hope that it will be useful, but WITHOUT ANY
15 : WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 : FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 : for more details.
18 :
19 : You should have received a copy of the GNU General Public License
20 : along with GCC; see the file COPYING3. If not see
21 : <http://www.gnu.org/licenses/>. */
22 :
23 : #include "config.h"
24 : #include "system.h"
25 : #include "coretypes.h"
26 : #include "target.h"
27 : #include "cp-tree.h"
28 : #include "stringpool.h"
29 : #include "stmt.h"
30 : #include "stor-layout.h"
31 : #include "tree-iterator.h"
32 : #include "tree.h"
33 : #include "gcc-rich-location.h"
34 : #include "hash-map.h"
35 : #include "coroutines.h"
36 :
37 : /* ================= Debug. ================= */
38 :
39 : #include "langhooks.h"
40 : #include "cxx-pretty-print.h"
41 :
42 : /* Walk through the fields of the type TYP and print them to the pretty printer
43 : PP. */
44 :
45 : static void
46 0 : dump_record_fields (cxx_pretty_printer *pp, tree typ)
47 : {
48 0 : pp->type_id (typ);
49 0 : pp_newline_and_indent (pp, 2);
50 0 : pp_left_brace (pp);
51 0 : pp_indentation (pp) += 2;
52 :
53 : /* We'll be on a new line, we don't need padding. */
54 0 : pp->set_padding (pp_none);
55 :
56 0 : for (tree tmp = TYPE_FIELDS (typ); tmp; tmp = DECL_CHAIN (tmp))
57 : {
58 0 : pp_newline_and_indent (pp, 0);
59 0 : pp->declaration (tmp);
60 : }
61 :
62 0 : pp_newline_and_indent (pp, -2);
63 0 : pp_right_brace (pp);
64 0 : pp_newline_and_indent (pp, -2);
65 0 : }
66 :
67 : /* The lang-coro stream. */
68 : static FILE *dmp_str = NULL;
69 :
70 : /* ID of the lang-coro dump. */
71 : int coro_dump_id;
72 :
73 : /* Flags passed to the lang-coro dump. */
74 : static dump_flags_t coro_dump_flags;
75 :
76 : /* Pretty print the function FNDECL, which ought to be a coroutine before
77 : co_await expansion, into the lang-coro dump, if it is enabled. */
78 :
79 : static void
80 1673 : coro_maybe_dump_initial_function (tree fndecl)
81 : {
82 1673 : if (!dmp_str)
83 1673 : return;
84 :
85 0 : bool lambda_p = LAMBDA_TYPE_P (DECL_CONTEXT (fndecl));
86 0 : fprintf (dmp_str, "%s %s original:\n",
87 : (lambda_p ? "Lambda" : "Function"),
88 0 : lang_hooks.decl_printable_name (fndecl, 2));
89 :
90 0 : cxx_pretty_printer pp;
91 0 : pp.set_output_stream (dmp_str);
92 0 : pp.flags = coro_dump_flags;
93 0 : pp.declaration (fndecl);
94 0 : pp_newline_and_flush (&pp);
95 0 : }
96 :
97 : /* Pretty print the RAMP function to the lang-coro dump, if it is enabled. */
98 :
99 : static void
100 1610 : coro_maybe_dump_ramp (tree ramp)
101 : {
102 1610 : if (!dmp_str)
103 1610 : return;
104 :
105 0 : cxx_pretty_printer pp;
106 0 : pp.set_output_stream (dmp_str);
107 0 : pp.flags = coro_dump_flags;
108 :
109 0 : pp_string (&pp, "Ramp function:");
110 0 : pp_newline_and_indent (&pp, 0);
111 0 : pp.declaration (ramp);
112 0 : pp_newline_and_flush (&pp);
113 0 : }
114 :
115 : /* For a given ACTOR and DESTROY, if lang-coro dumping is enabled, pretty-print
116 : their contents to the lang-coro dump. */
117 :
118 : static void
119 1589 : coro_maybe_dump_transformed_functions (tree actor, tree destroy)
120 : {
121 1589 : if (!dmp_str)
122 1589 : return;
123 :
124 0 : cxx_pretty_printer pp;
125 0 : pp.set_output_stream (dmp_str);
126 0 : pp.flags = coro_dump_flags;
127 :
128 0 : if (!actor || actor == error_mark_node)
129 : {
130 0 : pp_string (&pp, "Transform failed");
131 0 : pp_newline_and_flush (&pp);
132 0 : return;
133 : }
134 :
135 0 : tree frame = TREE_TYPE (TREE_TYPE (DECL_ARGUMENTS (actor)));
136 0 : pp_string (&pp, "Frame type:");
137 0 : pp_newline (&pp);
138 0 : dump_record_fields (&pp, frame);
139 0 : pp_newline_and_flush (&pp);
140 :
141 0 : pp_string (&pp, "Actor/resumer:");
142 0 : pp_newline (&pp);
143 0 : pp.declaration (actor);
144 0 : pp_newline_and_flush (&pp);
145 :
146 0 : pp_string (&pp, "Destroyer:");
147 0 : pp_newline (&pp);
148 0 : pp.declaration (destroy);
149 0 : pp_newline_and_flush (&pp);
150 0 : }
151 :
152 : /* ================= END Debug. ================= */
153 :
154 : static bool coro_promise_type_found_p (tree, location_t);
155 :
156 : /* GCC C++ coroutines implementation.
157 :
158 : The user authors a function that becomes a coroutine (lazily) by
159 : making use of any of the co_await, co_yield or co_return keywords.
160 :
161 : Unlike a regular function, where the activation record is placed on the
162 : stack, and is destroyed on function exit, a coroutine has some state that
163 : persists between calls - the coroutine frame (analogous to a stack frame).
164 :
165 : We transform the user's function into three pieces:
166 : 1. A so-called ramp function, that establishes the coroutine frame and
167 : begins execution of the coroutine.
168 : 2. An actor function that contains the state machine corresponding to the
169 : user's suspend/resume structure.
170 : 3. A stub function that calls the actor function in 'destroy' mode.
171 :
172 : The actor function is executed:
173 : * from "resume point 0" by the ramp.
174 : * from resume point N ( > 0 ) for handle.resume() calls.
175 : * from the destroy stub for destroy point N for handle.destroy() calls.
176 :
177 : The functions in this file carry out the necessary analysis of, and
178 : transforms to, the AST to perform this.
179 :
180 : The C++ coroutine design makes use of some helper functions that are
181 : authored in a so-called "promise" class provided by the user.
182 :
183 : At parse time (or post substitution) the type of the coroutine promise
184 : will be determined. At that point, we can look up the required promise
185 : class methods and issue diagnostics if they are missing or incorrect. To
186 : avoid repeating these actions at code-gen time, we make use of temporary
187 : 'proxy' variables for the coroutine handle and the promise - which will
188 : eventually be instantiated in the coroutine frame.
189 :
190 : Each of the keywords will expand to a code sequence (although co_yield is
191 : just syntactic sugar for a co_await).
192 :
193 : We defer the analysis and transformation until template expansion is
194 : complete so that we have complete types at that time.
195 :
196 : ---------------------------------------------------------------------------
197 :
198 : Coroutine state, and responsibility for its release.
199 :
200 : As noted above, a coroutine has some state that persists across suspensions.
201 :
202 : The state has two components:
203 : * State that is specified by the standard and persists for the entire
204 : life of the coroutine.
205 : * Local state that is constructed/destructed as scopes in the original
206 : function body are entered/exited. The destruction of local state is
207 : always the responsibility of the body code.
208 :
209 : The persistent state (and the overall storage for the state) must be
210 : managed in two places:
211 : * The ramp function (which allocates and builds this - and can, in some
212 : cases, be responsible for destroying it)
213 : * The re-written function body which can destroy it when that body
214 : completes its final suspend - or when the handle.destroy () is called.
215 :
216 : In all cases the ramp holds responsibility for constructing the standard-
217 : mandated persistent state.
218 :
219 : There are four ways in which the ramp might be re-entered after starting
220 : the function body:
221 : A The body could suspend (one might expect that to be the 'normal' case
222 : for most coroutines).
223 : B The body might complete either synchronously or via continuations.
224 : C An exception might be thrown during the setup of the initial await
225 : expression, before the initial awaiter resumes.
226 : D An exception might be processed by promise.unhandled_exception () and
227 : that, in turn, might re-throw it (or throw something else). In this
228 : case, the coroutine is considered suspended at the final suspension
229 : point.
230 :
231 : Until the ramp return value has been constructed, the ramp is considered
232 : to have a use of the state.
233 :
234 : To manage these interacting conditions we allocate a reference counter
235 : for the frame state. This is initialised to 1 by the ramp as part of its
236 : startup (note that failures/exceptions in the startup code are handled
237 : locally to the ramp).
238 :
239 : When the body returns (either normally, or by exception) the ramp releases
240 : its use.
241 :
242 : Once the rewritten coroutine body is started, the body is considered to
243 : have a use of the frame. This use (potentially) needs to be released if
244 : an exception is thrown from the body. We implement this using an eh-only
245 : cleanup around the initial await and function body. If we have the case
246 : D above, then we do not release the use.
247 :
248 : In case:
249 :
250 : A, typically the ramp would be re-entered with the body holding a use,
251 : and therefore the ramp should not destroy the state.
252 :
253 : B, both the body and ramp will have released their uses, and the ramp
254 : should destroy the state.
255 :
256 : C, we must arrange for the body to release its use, because we require
257 : the ramp to cleanup in this circumstance.
258 :
259 : D is an outlier, since the responsibility for destruction of the state
260 : now rests with the user's code (via a handle.destroy() call).
261 :
262 : NOTE: In the case that the body has never suspended before such an
263 : exception occurs, the only reasonable way for the user code to obtain the
264 : necessary handle is if unhandled_exception() throws the handle or some
265 : object that contains the handle. That is outside of the designs here -
266 : if the user code might need this corner-case, then such provision will
267 : have to be made.
268 :
269 : In the ramp, we implement destruction for the persistent frame state by
270 : means of cleanups. These are run conditionally when the reference count
271 : is 0 signalling that both the body and the ramp have completed.
272 :
273 : In the body, once we pass the final suspend, then we test the use and
274 : delete the state if the use is 0. */
275 :
276 : /* The state that we collect during parsing (and template expansion) for
277 : a coroutine. */
278 :
279 2484 : struct GTY((for_user)) coroutine_info
280 : {
281 : tree function_decl; /* The original function decl. */
282 : tree actor_decl; /* The synthesized actor function. */
283 : tree destroy_decl; /* The synthesized destroy function. */
284 : tree promise_type; /* The cached promise type for this function. */
285 : tree traits_type; /* The cached traits type for this function. */
286 : tree handle_type; /* The cached coroutine handle for this function. */
287 : tree self_h_proxy; /* A handle instance that is used as the proxy for the
288 : one that will eventually be built in lowering. */
289 : tree promise_proxy; /* Likewise, a proxy promise instance. */
290 : tree from_address; /* handle_type from_address() function. */
291 : tree return_void; /* The expression for p.return_void(), if it exists. */
292 : location_t first_coro_keyword; /* The location of the keyword that made this
293 : function into a coroutine. */
294 :
295 : /* Temporary variable number assigned by get_awaitable_var. */
296 : int awaitable_number = 0;
297 :
298 : /* Flags to avoid repeated errors for per-function issues. */
299 : bool coro_ret_type_error_emitted;
300 : bool coro_promise_error_emitted;
301 : bool coro_co_return_error_emitted;
302 : };
303 :
304 : struct coroutine_info_hasher : ggc_ptr_hash<coroutine_info>
305 : {
306 : typedef tree compare_type; /* We only compare the function decl. */
307 : static inline hashval_t hash (coroutine_info *);
308 : static inline hashval_t hash (const compare_type &);
309 : static inline bool equal (coroutine_info *, coroutine_info *);
310 : static inline bool equal (coroutine_info *, const compare_type &);
311 : };
312 :
313 : /* This table holds all the collected coroutine state for coroutines in
314 : the current translation unit. */
315 :
316 : static GTY (()) hash_table<coroutine_info_hasher> *coroutine_info_table;
317 :
318 : /* We will initialize state lazily. */
319 : static bool coro_initialized = false;
320 :
321 : /* Return a hash value for the entry pointed to by INFO.
322 : The compare type is a tree, but the only trees we are going use are
323 : function decls. We use the DECL_UID as the hash value since that is
324 : stable across PCH. */
325 :
326 : hashval_t
327 67818 : coroutine_info_hasher::hash (coroutine_info *info)
328 : {
329 67818 : return DECL_UID (info->function_decl);
330 : }
331 :
332 : /* Return a hash value for the compare value COMP. */
333 :
334 : hashval_t
335 63477 : coroutine_info_hasher::hash (const compare_type& comp)
336 : {
337 63477 : return DECL_UID (comp);
338 : }
339 :
340 : /* Return true if the entries pointed to by LHS and RHS are for the
341 : same coroutine. */
342 :
343 : bool
344 : coroutine_info_hasher::equal (coroutine_info *lhs, coroutine_info *rhs)
345 : {
346 : return lhs->function_decl == rhs->function_decl;
347 : }
348 :
349 : bool
350 86636 : coroutine_info_hasher::equal (coroutine_info *lhs, const compare_type& rhs)
351 : {
352 86636 : return lhs->function_decl == rhs;
353 : }
354 :
355 : /* Initialize the coroutine info table, to hold state per coroutine decl,
356 : if not already created. */
357 :
358 : static void
359 2040 : create_coroutine_info_table ()
360 : {
361 2040 : if (!coroutine_info_table)
362 2037 : coroutine_info_table = hash_table<coroutine_info_hasher>::create_ggc (11);
363 2040 : }
364 :
365 : /* Get the existing coroutine_info for FN_DECL, or insert a new one if the
366 : entry does not yet exist. */
367 :
368 : static coroutine_info *
369 9813 : get_or_insert_coroutine_info (tree fn_decl)
370 : {
371 9813 : gcc_checking_assert (coroutine_info_table != NULL);
372 :
373 9813 : coroutine_info **slot = coroutine_info_table->find_slot_with_hash
374 9813 : (fn_decl, coroutine_info_hasher::hash (fn_decl), INSERT);
375 :
376 9813 : if (*slot == NULL)
377 : {
378 2484 : *slot = new (ggc_cleared_alloc<coroutine_info> ()) coroutine_info ();
379 2484 : (*slot)->function_decl = fn_decl;
380 : }
381 :
382 9813 : return *slot;
383 : }
384 :
385 : /* Get the existing coroutine_info for FN_DECL, fail if it doesn't exist. */
386 :
387 : static coroutine_info *
388 53667 : get_coroutine_info (tree fn_decl)
389 : {
390 53667 : if (coroutine_info_table == NULL)
391 : return NULL;
392 :
393 53664 : coroutine_info **slot = coroutine_info_table->find_slot_with_hash
394 53664 : (fn_decl, coroutine_info_hasher::hash (fn_decl), NO_INSERT);
395 53664 : if (slot)
396 53664 : return *slot;
397 : return NULL;
398 : }
399 :
400 : /* We will lazily create all the identifiers that are used by coroutines
401 : on the first attempt to lookup the traits. */
402 :
403 : /* Identifiers that are used by all coroutines. */
404 :
405 : static GTY(()) tree coro_traits_identifier;
406 : static GTY(()) tree coro_handle_identifier;
407 : static GTY(()) tree coro_promise_type_identifier;
408 :
409 : /* Required promise method name identifiers. */
410 :
411 : static GTY(()) tree coro_await_transform_identifier;
412 : static GTY(()) tree coro_initial_suspend_identifier;
413 : static GTY(()) tree coro_final_suspend_identifier;
414 : static GTY(()) tree coro_return_void_identifier;
415 : static GTY(()) tree coro_return_value_identifier;
416 : static GTY(()) tree coro_yield_value_identifier;
417 : static GTY(()) tree coro_address_identifier;
418 : static GTY(()) tree coro_from_address_identifier;
419 : static GTY(()) tree coro_get_return_object_identifier;
420 : static GTY(()) tree coro_gro_on_allocation_fail_identifier;
421 : static GTY(()) tree coro_unhandled_exception_identifier;
422 :
423 : /* Awaitable methods. */
424 :
425 : static GTY(()) tree coro_await_ready_identifier;
426 : static GTY(()) tree coro_await_suspend_identifier;
427 : static GTY(()) tree coro_await_resume_identifier;
428 :
429 : /* Accessors for the coroutine frame state used by the implementation. */
430 :
431 : static GTY(()) tree coro_resume_fn_id;
432 : static GTY(()) tree coro_destroy_fn_id;
433 : static GTY(()) tree coro_promise_id;
434 : static GTY(()) tree coro_frame_needs_free_id;
435 : static GTY(()) tree coro_resume_index_id;
436 : static GTY(()) tree coro_self_handle_id;
437 : static GTY(()) tree coro_actor_continue_id;
438 : static GTY(()) tree coro_frame_i_a_r_c_id;
439 : static GTY(()) tree coro_frame_refcount_id;
440 :
441 : /* Create the identifiers used by the coroutines library interfaces and
442 : the implementation frame state. */
443 :
444 : static void
445 2121 : coro_init_identifiers ()
446 : {
447 2121 : coro_traits_identifier = get_identifier ("coroutine_traits");
448 2121 : coro_handle_identifier = get_identifier ("coroutine_handle");
449 2121 : coro_promise_type_identifier = get_identifier ("promise_type");
450 :
451 2121 : coro_await_transform_identifier = get_identifier ("await_transform");
452 2121 : coro_initial_suspend_identifier = get_identifier ("initial_suspend");
453 2121 : coro_final_suspend_identifier = get_identifier ("final_suspend");
454 2121 : coro_return_void_identifier = get_identifier ("return_void");
455 2121 : coro_return_value_identifier = get_identifier ("return_value");
456 2121 : coro_yield_value_identifier = get_identifier ("yield_value");
457 2121 : coro_address_identifier = get_identifier ("address");
458 2121 : coro_from_address_identifier = get_identifier ("from_address");
459 2121 : coro_get_return_object_identifier = get_identifier ("get_return_object");
460 4242 : coro_gro_on_allocation_fail_identifier =
461 2121 : get_identifier ("get_return_object_on_allocation_failure");
462 2121 : coro_unhandled_exception_identifier = get_identifier ("unhandled_exception");
463 :
464 2121 : coro_await_ready_identifier = get_identifier ("await_ready");
465 2121 : coro_await_suspend_identifier = get_identifier ("await_suspend");
466 2121 : coro_await_resume_identifier = get_identifier ("await_resume");
467 :
468 : /* Coroutine state frame field accessors. */
469 2121 : coro_resume_fn_id = get_identifier ("_Coro_resume_fn");
470 2121 : coro_destroy_fn_id = get_identifier ("_Coro_destroy_fn");
471 2121 : coro_promise_id = get_identifier ("_Coro_promise");
472 2121 : coro_frame_needs_free_id = get_identifier ("_Coro_frame_needs_free");
473 2121 : coro_frame_i_a_r_c_id = get_identifier ("_Coro_initial_await_resume_called");
474 2121 : coro_resume_index_id = get_identifier ("_Coro_resume_index");
475 2121 : coro_self_handle_id = get_identifier ("_Coro_self_handle");
476 2121 : coro_actor_continue_id = get_identifier ("_Coro_actor_continue");
477 2121 : coro_frame_refcount_id = get_identifier ("_Coro_frame_refcount");
478 2121 : }
479 :
480 : /* Trees we only need to set up once. */
481 :
482 : static GTY(()) tree coro_traits_templ;
483 : static GTY(()) tree coro_handle_templ;
484 : static GTY(()) tree void_coro_handle_type;
485 : static GTY(()) tree void_coro_handle_address;
486 :
487 : /* ================= Parse, Semantics and Type checking ================= */
488 :
489 : /* This initial set of routines are helper for the parsing and template
490 : expansion phases.
491 :
492 : At the completion of this, we will have completed trees for each of the
493 : keywords, but making use of proxy variables for the self-handle and the
494 : promise class instance. */
495 :
496 : /* [coroutine.traits]
497 : Lookup the coroutine_traits template decl. */
498 :
499 : static tree
500 2121 : find_coro_traits_template_decl (location_t kw)
501 : {
502 : /* If we are missing fundamental information, such as the traits, (or the
503 : declaration found is not a type template), then don't emit an error for
504 : every keyword in a TU, just do it once. */
505 2121 : static bool traits_error_emitted = false;
506 :
507 4242 : tree traits_decl = lookup_qualified_name (std_node, coro_traits_identifier,
508 : LOOK_want::NORMAL,
509 2121 : /*complain=*/!traits_error_emitted);
510 2121 : if (traits_decl == error_mark_node
511 2121 : || !DECL_TYPE_TEMPLATE_P (traits_decl))
512 : {
513 30 : if (!traits_error_emitted)
514 : {
515 12 : auto_diagnostic_group d;
516 12 : gcc_rich_location richloc (kw);
517 12 : error_at (&richloc, "coroutines require a traits template; cannot"
518 : " find %<%E::%E%>", std_node, coro_traits_identifier);
519 12 : inform (&richloc, "perhaps %<#include <coroutine>%> is missing");
520 12 : traits_error_emitted = true;
521 12 : }
522 30 : return NULL_TREE;
523 : }
524 : else
525 : return traits_decl;
526 : }
527 :
528 : /* Instantiate Coroutine traits for the function signature. */
529 :
530 : static tree
531 2481 : instantiate_coro_traits (tree fndecl, location_t kw)
532 : {
533 : /* [coroutine.traits.primary]
534 : So now build up a type list for the template <typename _R, typename...>.
535 : The types are the function's arg types and _R is the function return
536 : type. */
537 :
538 2481 : tree functyp = TREE_TYPE (fndecl);
539 2481 : tree arg = DECL_ARGUMENTS (fndecl);
540 2481 : tree arg_node = TYPE_ARG_TYPES (functyp);
541 2481 : tree argtypes = make_tree_vec (list_length (arg_node)-1);
542 2481 : unsigned p = 0;
543 :
544 16153 : while (arg_node != NULL_TREE && !VOID_TYPE_P (TREE_VALUE (arg_node)))
545 : {
546 4355 : if (is_this_parameter (arg)
547 4355 : || DECL_NAME (arg) == closure_identifier)
548 : {
549 : /* We pass a reference to *this to the param preview. */
550 941 : tree ct = TREE_TYPE (TREE_TYPE (arg));
551 941 : TREE_VEC_ELT (argtypes, p++) = cp_build_reference_type (ct, false);
552 : }
553 : else
554 3414 : TREE_VEC_ELT (argtypes, p++) = TREE_VALUE (arg_node);
555 :
556 4355 : arg_node = TREE_CHAIN (arg_node);
557 4355 : arg = DECL_CHAIN (arg);
558 : }
559 :
560 2481 : tree argtypepack = cxx_make_type (TYPE_ARGUMENT_PACK);
561 2481 : ARGUMENT_PACK_ARGS (argtypepack) = argtypes;
562 :
563 2481 : tree targ = make_tree_vec (2);
564 2481 : TREE_VEC_ELT (targ, 0) = TREE_TYPE (functyp);
565 2481 : TREE_VEC_ELT (targ, 1) = argtypepack;
566 :
567 2481 : tree traits_class
568 2481 : = lookup_template_class (coro_traits_templ, targ,
569 : /*in_decl=*/NULL_TREE, /*context=*/NULL_TREE,
570 : tf_warning_or_error);
571 :
572 2481 : if (traits_class == error_mark_node)
573 : {
574 0 : error_at (kw, "cannot instantiate %<coroutine traits%>");
575 0 : return NULL_TREE;
576 : }
577 :
578 : return traits_class;
579 : }
580 :
581 : /* [coroutine.handle] */
582 :
583 : static tree
584 2091 : find_coro_handle_template_decl (location_t kw)
585 : {
586 : /* As for the coroutine traits, this error is per TU, so only emit
587 : it once. */
588 2091 : static bool coro_handle_error_emitted = false;
589 4182 : tree handle_decl = lookup_qualified_name (std_node, coro_handle_identifier,
590 : LOOK_want::NORMAL,
591 2091 : !coro_handle_error_emitted);
592 2091 : if (handle_decl == error_mark_node
593 2091 : || !DECL_CLASS_TEMPLATE_P (handle_decl))
594 : {
595 18 : if (!coro_handle_error_emitted)
596 6 : error_at (kw, "coroutines require a handle class template;"
597 : " cannot find %<%E::%E%>", std_node, coro_handle_identifier);
598 18 : coro_handle_error_emitted = true;
599 18 : return NULL_TREE;
600 : }
601 : else
602 : return handle_decl;
603 : }
604 :
605 : /* Get and validate HANDLE_TYPE::address. The resulting function, if any, will
606 : be a non-overloaded member function that takes no arguments and returns
607 : void*. If that is not the case, signals an error and returns NULL_TREE. */
608 :
609 : static tree
610 2073 : get_handle_type_address (location_t kw, tree handle_type)
611 : {
612 2073 : tree addr_getter = lookup_member (handle_type, coro_address_identifier, 1,
613 : 0, tf_warning_or_error);
614 2073 : if (!addr_getter || addr_getter == error_mark_node)
615 : {
616 18 : qualified_name_lookup_error (handle_type, coro_address_identifier,
617 : error_mark_node, kw);
618 18 : return NULL_TREE;
619 : }
620 :
621 2055 : if (!BASELINK_P (addr_getter)
622 2055 : || TREE_CODE (TREE_TYPE (addr_getter)) != METHOD_TYPE)
623 : {
624 18 : error_at (kw, "%qE must be a non-overloaded method", addr_getter);
625 18 : return NULL_TREE;
626 : }
627 :
628 2037 : tree fn_t = TREE_TYPE (addr_getter);
629 2037 : tree arg = TYPE_ARG_TYPES (fn_t);
630 :
631 : /* Skip the 'this' pointer. */
632 2037 : arg = TREE_CHAIN (arg);
633 :
634 : /* Check that from_addr has the argument list (). */
635 2037 : if (arg != void_list_node)
636 : {
637 0 : error_at (kw, "%qE must take no arguments", addr_getter);
638 0 : return NULL_TREE;
639 : }
640 :
641 2037 : tree ret_t = TREE_TYPE (fn_t);
642 2037 : if (!same_type_p (ret_t, ptr_type_node))
643 : {
644 0 : error_at (kw, "%qE must return %qT, not %qT",
645 : addr_getter, ptr_type_node, ret_t);
646 0 : return NULL_TREE;
647 : }
648 :
649 : return addr_getter;
650 : }
651 :
652 : /* Get and validate HANDLE_TYPE::from_address. The resulting function, if
653 : any, will be a non-overloaded static function that takes a single void* and
654 : returns HANDLE_TYPE. If that is not the case, signals an error and returns
655 : NULL_TREE. */
656 :
657 : static tree
658 1661 : get_handle_type_from_address (location_t kw, tree handle_type)
659 : {
660 1661 : tree from_addr = lookup_member (handle_type, coro_from_address_identifier, 1,
661 : 0, tf_warning_or_error);
662 1661 : if (!from_addr || from_addr == error_mark_node)
663 : {
664 6 : qualified_name_lookup_error (handle_type, coro_from_address_identifier,
665 : error_mark_node, kw);
666 6 : return NULL_TREE;
667 : }
668 1655 : if (!BASELINK_P (from_addr)
669 1655 : || TREE_CODE (TREE_TYPE (from_addr)) != FUNCTION_TYPE)
670 : {
671 3 : error_at (kw, "%qE must be a non-overloaded static function", from_addr);
672 3 : return NULL_TREE;
673 : }
674 :
675 1652 : tree fn_t = TREE_TYPE (from_addr);
676 1652 : tree arg = TYPE_ARG_TYPES (fn_t);
677 : /* Check that from_addr has the argument list (void*). */
678 1652 : if (!arg
679 1652 : || !same_type_p (TREE_VALUE (arg), ptr_type_node)
680 3304 : || TREE_CHAIN (arg) != void_list_node)
681 : {
682 0 : error_at (kw, "%qE must take a single %qT", from_addr, ptr_type_node);
683 0 : return NULL_TREE;
684 : }
685 :
686 1652 : tree ret_t = TREE_TYPE (fn_t);
687 1652 : if (!same_type_p (ret_t, handle_type))
688 : {
689 0 : error_at (kw, "%qE must return %qT, not %qT",
690 : from_addr, handle_type, ret_t);
691 0 : return NULL_TREE;
692 : }
693 :
694 : return from_addr;
695 : }
696 :
697 : static tree
698 3734 : instantiate_coro_handle_for_promise_type (location_t kw, tree promise_type)
699 : {
700 : /* So now build up a type list for the template, one entry, the promise. */
701 3734 : tree targ = make_tree_vec (1);
702 3734 : TREE_VEC_ELT (targ, 0) = promise_type;
703 3734 : tree handle_type
704 3734 : = lookup_template_class (coro_handle_identifier, targ,
705 : /* in_decl=*/NULL_TREE,
706 : /* context=*/std_node,
707 : tf_warning_or_error);
708 :
709 3734 : if (handle_type == error_mark_node)
710 : {
711 0 : error_at (kw, "cannot instantiate a %<coroutine handle%> for"
712 : " promise type %qT", promise_type);
713 0 : return NULL_TREE;
714 : }
715 :
716 : return handle_type;
717 : }
718 :
719 : /* Look for the promise_type in the instantiated traits. */
720 :
721 : static tree
722 1685 : find_promise_type (tree traits_class)
723 : {
724 1685 : tree promise_type
725 1685 : = lookup_member (traits_class, coro_promise_type_identifier,
726 : /* protect=*/1, /*want_type=*/true, tf_warning_or_error);
727 :
728 1685 : if (promise_type)
729 1667 : promise_type
730 1667 : = complete_type_or_else (TREE_TYPE (promise_type), promise_type);
731 :
732 : /* NULL_TREE on fail. */
733 1685 : return promise_type;
734 : }
735 :
736 : /* Perform initialization of the coroutine processor state, if not done
737 : before. */
738 :
739 : static bool
740 8209 : ensure_coro_initialized (location_t loc)
741 : {
742 8209 : if (!coro_initialized)
743 : {
744 : /* Trees we only need to create once.
745 : Set up the identifiers we will use. */
746 2121 : coro_init_identifiers ();
747 :
748 : /* Coroutine traits template. */
749 2121 : coro_traits_templ = find_coro_traits_template_decl (loc);
750 2121 : if (coro_traits_templ == NULL_TREE)
751 : return false;
752 :
753 : /* coroutine_handle<> template. */
754 2091 : coro_handle_templ = find_coro_handle_template_decl (loc);
755 2091 : if (coro_handle_templ == NULL_TREE)
756 : return false;
757 :
758 : /* We can also instantiate the void coroutine_handle<> */
759 2073 : void_coro_handle_type
760 2073 : = instantiate_coro_handle_for_promise_type (loc, void_type_node);
761 2073 : if (void_coro_handle_type == NULL_TREE)
762 : return false;
763 :
764 2073 : void_coro_handle_address
765 2073 : = get_handle_type_address (loc, void_coro_handle_type);
766 2073 : if (!void_coro_handle_address)
767 : return false;
768 :
769 2037 : create_coroutine_info_table ();
770 2037 : if (coroutine_info_table == NULL)
771 : return false;
772 :
773 2037 : coro_initialized = true;
774 : }
775 : return true;
776 : }
777 :
778 : /* Try to get the coroutine traits class. */
779 : static tree
780 5406 : coro_get_traits_class (tree fndecl, location_t loc)
781 : {
782 5406 : gcc_assert (fndecl != NULL_TREE);
783 5406 : gcc_assert (coro_initialized);
784 :
785 5406 : coroutine_info *coro_info = get_or_insert_coroutine_info (fndecl);
786 5406 : auto& traits_type = coro_info->traits_type;
787 5406 : if (!traits_type)
788 2481 : traits_type = instantiate_coro_traits (fndecl, loc);
789 5406 : return traits_type;
790 : }
791 :
792 : static bool
793 4440 : coro_promise_type_found_p (tree fndecl, location_t loc)
794 : {
795 4440 : gcc_assert (fndecl != NULL_TREE);
796 :
797 4440 : if (!ensure_coro_initialized (loc))
798 : return false;
799 :
800 : /* Save the coroutine data on the side to avoid the overhead on every
801 : function decl tree. */
802 :
803 4404 : coroutine_info *coro_info = get_or_insert_coroutine_info (fndecl);
804 : /* Without this, we cannot really proceed. */
805 4404 : gcc_checking_assert (coro_info);
806 :
807 : /* If we don't already have a current promise type, try to look it up. */
808 4404 : if (coro_info->promise_type == NULL_TREE)
809 : {
810 : /* Get the coroutine traits template class instance for the function
811 : signature we have - coroutine_traits <R, ...> */
812 :
813 1685 : tree templ_class = coro_get_traits_class (fndecl, loc);
814 :
815 : /* Find the promise type for that. */
816 1685 : coro_info->promise_type = find_promise_type (templ_class);
817 :
818 : /* If we don't find it, punt on the rest. */
819 1685 : if (coro_info->promise_type == NULL_TREE)
820 : {
821 18 : if (!coro_info->coro_promise_error_emitted)
822 6 : error_at (loc, "unable to find the promise type for"
823 : " this coroutine");
824 18 : coro_info->coro_promise_error_emitted = true;
825 18 : return false;
826 : }
827 :
828 : /* Test for errors in the promise type that can be determined now. */
829 1667 : tree has_ret_void = lookup_member (coro_info->promise_type,
830 : coro_return_void_identifier,
831 : /*protect=*/1, /*want_type=*/0,
832 : tf_none);
833 1667 : tree has_ret_val = lookup_member (coro_info->promise_type,
834 : coro_return_value_identifier,
835 : /*protect=*/1, /*want_type=*/0,
836 : tf_none);
837 1667 : if (has_ret_void && has_ret_val)
838 : {
839 6 : auto_diagnostic_group d;
840 6 : location_t ploc = DECL_SOURCE_LOCATION (fndecl);
841 6 : if (!coro_info->coro_co_return_error_emitted)
842 6 : error_at (ploc, "the coroutine promise type %qT declares both"
843 : " %<return_value%> and %<return_void%>",
844 : coro_info->promise_type);
845 6 : inform (DECL_SOURCE_LOCATION (BASELINK_FUNCTIONS (has_ret_void)),
846 : "%<return_void%> declared here");
847 6 : has_ret_val = BASELINK_FUNCTIONS (has_ret_val);
848 6 : const char *message = "%<return_value%> declared here";
849 6 : if (TREE_CODE (has_ret_val) == OVERLOAD)
850 : {
851 6 : has_ret_val = OVL_FIRST (has_ret_val);
852 : message = "%<return_value%> first declared here";
853 : }
854 6 : inform (DECL_SOURCE_LOCATION (has_ret_val), message);
855 6 : coro_info->coro_co_return_error_emitted = true;
856 6 : return false;
857 6 : }
858 :
859 : /* Try to find the handle type for the promise. */
860 1661 : tree handle_type
861 1661 : = instantiate_coro_handle_for_promise_type (loc, coro_info->promise_type);
862 1661 : if (handle_type == NULL_TREE)
863 : return false;
864 1661 : tree from_address = get_handle_type_from_address (loc, handle_type);
865 1661 : if (from_address == NULL_TREE)
866 : return false;
867 :
868 : /* Complete this, we're going to use it. */
869 1652 : coro_info->handle_type = complete_type_or_else (handle_type, fndecl);
870 1652 : coro_info->from_address = from_address;
871 :
872 : /* Diagnostic would be emitted by complete_type_or_else. */
873 1652 : if (!coro_info->handle_type)
874 : return false;
875 :
876 : /* Build a proxy for a handle to "self" as the param to
877 : await_suspend() calls. */
878 1652 : coro_info->self_h_proxy
879 1652 : = build_lang_decl (VAR_DECL, coro_self_handle_id,
880 : coro_info->handle_type);
881 1652 : DECL_CONTEXT (coro_info->self_h_proxy) = fndecl;
882 :
883 : /* Build a proxy for the promise so that we can perform lookups. */
884 1652 : coro_info->promise_proxy
885 1652 : = build_lang_decl (VAR_DECL, coro_promise_id,
886 : coro_info->promise_type);
887 1652 : DECL_CONTEXT (coro_info->promise_proxy) = fndecl;
888 :
889 : /* Note where we first saw a coroutine keyword. */
890 1652 : coro_info->first_coro_keyword = loc;
891 : }
892 :
893 : return true;
894 : }
895 :
896 : /* Map from actor or destroyer to ramp. */
897 : static GTY(()) hash_map<tree, tree> *to_ramp;
898 :
899 : /* Given a tree that is an actor or destroy, find the ramp function. */
900 :
901 : tree
902 262296220 : coro_get_ramp_function (tree decl)
903 : {
904 262296220 : if (!to_ramp)
905 : return NULL_TREE;
906 960365 : tree *p = to_ramp->get (decl);
907 960365 : if (p)
908 6619 : return *p;
909 : return NULL_TREE;
910 : }
911 :
912 : /* Given a DECL, an actor or destroyer, build a link from that to the ramp
913 : function. Used by modules streaming. */
914 :
915 : void
916 3226 : coro_set_ramp_function (tree decl, tree ramp)
917 : {
918 3226 : if (!to_ramp)
919 1393 : to_ramp = hash_map<tree, tree>::create_ggc (10);
920 3226 : to_ramp->put (decl, ramp);
921 3226 : }
922 :
923 : /* Given the DECL for a ramp function (the user's original declaration) return
924 : the actor function if it has been defined. */
925 :
926 : tree
927 3043 : coro_get_actor_function (tree decl)
928 : {
929 3043 : if (coroutine_info *info = get_coroutine_info (decl))
930 3043 : return info->actor_decl;
931 :
932 : return NULL_TREE;
933 : }
934 :
935 : /* Given the DECL for a ramp function (the user's original declaration) return
936 : the destroy function if it has been defined. */
937 :
938 : tree
939 1533 : coro_get_destroy_function (tree decl)
940 : {
941 1533 : if (coroutine_info *info = get_coroutine_info (decl))
942 1533 : return info->destroy_decl;
943 :
944 : return NULL_TREE;
945 : }
946 :
947 : /* For a given ramp function DECL, set the actor and destroy functions.
948 : This is only used by modules streaming. */
949 :
950 : void
951 3 : coro_set_transform_functions (tree decl, tree actor, tree destroy)
952 : {
953 : /* Only relevant with modules. */
954 3 : gcc_checking_assert (modules_p ());
955 :
956 : /* This should only be called for newly streamed declarations. */
957 3 : gcc_checking_assert (!get_coroutine_info (decl));
958 :
959 : /* This might be the first use of coroutine info in the TU, so
960 : create the coroutine info table if needed. */
961 3 : create_coroutine_info_table ();
962 :
963 3 : coroutine_info *coroutine = get_or_insert_coroutine_info (decl);
964 3 : coroutine->actor_decl = actor;
965 3 : coroutine->destroy_decl = destroy;
966 3 : }
967 :
968 : /* Given a CO_AWAIT_EXPR AWAIT_EXPR, return its resume call. */
969 :
970 : tree
971 230 : co_await_get_resume_call (tree await_expr)
972 : {
973 230 : gcc_checking_assert (TREE_CODE (await_expr) == CO_AWAIT_EXPR);
974 230 : tree vec = TREE_OPERAND (await_expr, 3);
975 230 : if (!vec)
976 : return nullptr;
977 218 : return TREE_VEC_ELT (vec, 2);
978 : }
979 :
980 :
981 : /* These functions assumes that the caller has verified that the state for
982 : the decl has been initialized, we try to minimize work here. */
983 :
984 : static tree
985 21685 : get_coroutine_promise_type (tree decl)
986 : {
987 21685 : if (coroutine_info *info = get_coroutine_info (decl))
988 20069 : return info->promise_type;
989 :
990 : return NULL_TREE;
991 : }
992 :
993 : static tree
994 1631 : get_coroutine_handle_type (tree decl)
995 : {
996 1631 : if (coroutine_info *info = get_coroutine_info (decl))
997 0 : return info->handle_type;
998 :
999 : return NULL_TREE;
1000 : }
1001 :
1002 : static tree
1003 5909 : get_coroutine_self_handle_proxy (tree decl)
1004 : {
1005 5909 : if (coroutine_info *info = get_coroutine_info (decl))
1006 5909 : return info->self_h_proxy;
1007 :
1008 : return NULL_TREE;
1009 : }
1010 :
1011 : static tree
1012 8674 : get_coroutine_promise_proxy (tree decl)
1013 : {
1014 8674 : if (coroutine_info *info = get_coroutine_info (decl))
1015 8674 : return info->promise_proxy;
1016 :
1017 : return NULL_TREE;
1018 : }
1019 :
1020 : static tree
1021 1589 : get_coroutine_from_address (tree decl)
1022 : {
1023 1589 : if (coroutine_info *info = get_coroutine_info (decl))
1024 0 : return info->from_address;
1025 :
1026 : return NULL_TREE;
1027 : }
1028 :
1029 : static tree
1030 13650 : lookup_promise_method (tree fndecl, tree member_id, location_t loc,
1031 : bool musthave)
1032 : {
1033 13650 : tree promise = get_coroutine_promise_type (fndecl);
1034 13650 : tree pm_memb
1035 13650 : = lookup_member (promise, member_id,
1036 : /*protect=*/1, /*want_type=*/0, tf_warning_or_error);
1037 13650 : if (musthave && pm_memb == NULL_TREE)
1038 : {
1039 21 : error_at (loc, "no member named %qE in %qT", member_id, promise);
1040 21 : return error_mark_node;
1041 : }
1042 : return pm_memb;
1043 : }
1044 :
1045 : /* Build an expression of the form p.method (args) where the p is a promise
1046 : object for the current coroutine.
1047 : OBJECT is the promise object instance to use, it may be NULL, in which case
1048 : we will use the promise_proxy instance for this coroutine.
1049 : ARGS may be NULL, for empty parm lists. */
1050 :
1051 : static tree
1052 9442 : coro_build_promise_expression (tree fn, tree promise_obj, tree member_id,
1053 : location_t loc, vec<tree, va_gc> **args,
1054 : bool musthave)
1055 : {
1056 9442 : tree meth = lookup_promise_method (fn, member_id, loc, musthave);
1057 9442 : if (meth == error_mark_node)
1058 : return error_mark_node;
1059 :
1060 : /* If we don't find it, and it isn't needed, an empty return is OK. */
1061 9424 : if (!meth)
1062 : return NULL_TREE;
1063 :
1064 8504 : tree promise
1065 8504 : = promise_obj ? promise_obj
1066 5280 : : get_coroutine_promise_proxy (current_function_decl);
1067 8504 : tree expr;
1068 8504 : if (BASELINK_P (meth))
1069 8406 : expr = build_new_method_call (promise, meth, args, NULL_TREE,
1070 : LOOKUP_NORMAL, NULL, tf_warning_or_error);
1071 : else
1072 : {
1073 98 : expr = build_class_member_access_expr (promise, meth, NULL_TREE,
1074 : true, tf_warning_or_error);
1075 98 : vec<tree, va_gc> *real_args;
1076 98 : if (!args)
1077 70 : real_args = make_tree_vector ();
1078 : else
1079 28 : real_args = *args;
1080 98 : expr = build_op_call (expr, &real_args, tf_warning_or_error);
1081 : }
1082 : return expr;
1083 : }
1084 :
1085 : /* Caching get for the expression p.return_void (). */
1086 :
1087 : static tree
1088 2113 : get_coroutine_return_void_expr (tree decl, location_t loc, bool musthave)
1089 : {
1090 2113 : if (coroutine_info *info = get_coroutine_info (decl))
1091 : {
1092 : /* If we don't have it try to build it. */
1093 2113 : if (!info->return_void)
1094 1625 : info->return_void
1095 1625 : = coro_build_promise_expression (current_function_decl, NULL,
1096 : coro_return_void_identifier,
1097 : loc, NULL, musthave);
1098 : /* Don't return an error if it's an optional call. */
1099 2113 : if (!musthave && info->return_void == error_mark_node)
1100 : return NULL_TREE;
1101 2110 : return info->return_void;
1102 : }
1103 0 : return musthave ? error_mark_node : NULL_TREE;
1104 : }
1105 :
1106 : /* Lookup an Awaitable member, which should be await_ready, await_suspend
1107 : or await_resume. */
1108 :
1109 : static tree
1110 12978 : lookup_awaitable_member (tree await_type, tree member_id, location_t loc)
1111 : {
1112 12978 : tree aw_memb
1113 12978 : = lookup_member (await_type, member_id,
1114 : /*protect=*/1, /*want_type=*/0, tf_warning_or_error);
1115 12978 : if (aw_memb == NULL_TREE)
1116 : {
1117 9 : error_at (loc, "no member named %qE in %qT", member_id, await_type);
1118 9 : return error_mark_node;
1119 : }
1120 : return aw_memb;
1121 : }
1122 :
1123 : /* Here we check the constraints that are common to all keywords (since the
1124 : presence of a coroutine keyword makes the function into a coroutine). */
1125 :
1126 : static bool
1127 3844 : coro_common_keyword_context_valid_p (tree fndecl, location_t kw_loc,
1128 : const char *kw_name)
1129 : {
1130 3844 : if (fndecl == NULL_TREE)
1131 : {
1132 12 : error_at (kw_loc, "%qs cannot be used outside a function", kw_name);
1133 12 : return false;
1134 : }
1135 :
1136 : /* This is arranged in order of prohibitions in the std. */
1137 3832 : if (DECL_MAIN_P (fndecl))
1138 : {
1139 : /* [basic.start.main] 3. The function main shall not be a coroutine. */
1140 9 : error_at (kw_loc, "%qs cannot be used in the %<main%> function",
1141 : kw_name);
1142 9 : return false;
1143 : }
1144 :
1145 3823 : if (DECL_DECLARED_CONSTEXPR_P (fndecl))
1146 : {
1147 15 : cp_function_chain->invalid_constexpr = true;
1148 15 : if (!is_instantiation_of_constexpr (fndecl))
1149 : {
1150 : /* [dcl.constexpr] 3.3 it shall not be a coroutine. */
1151 9 : error_at (kw_loc, "%qs cannot be used in a %<constexpr%> function",
1152 : kw_name);
1153 9 : return false;
1154 : }
1155 : }
1156 :
1157 3814 : if (FNDECL_USED_AUTO (fndecl))
1158 : {
1159 : /* [dcl.spec.auto] 15. A function declared with a return type that uses
1160 : a placeholder type shall not be a coroutine. */
1161 18 : error_at (kw_loc,
1162 : "%qs cannot be used in a function with a deduced return type",
1163 : kw_name);
1164 18 : return false;
1165 : }
1166 :
1167 3796 : if (varargs_function_p (fndecl))
1168 : {
1169 : /* [dcl.fct.def.coroutine] The parameter-declaration-clause of the
1170 : coroutine shall not terminate with an ellipsis that is not part
1171 : of a parameter-declaration. */
1172 9 : error_at (kw_loc,
1173 : "%qs cannot be used in a varargs function", kw_name);
1174 9 : return false;
1175 : }
1176 :
1177 7574 : if (DECL_CONSTRUCTOR_P (fndecl))
1178 : {
1179 : /* [class.ctor] 7. a constructor shall not be a coroutine. */
1180 9 : error_at (kw_loc, "%qs cannot be used in a constructor", kw_name);
1181 9 : return false;
1182 : }
1183 :
1184 3778 : if (DECL_DESTRUCTOR_P (fndecl))
1185 : {
1186 : /* [class.dtor] 21. a destructor shall not be a coroutine. */
1187 9 : error_at (kw_loc, "%qs cannot be used in a destructor", kw_name);
1188 9 : return false;
1189 : }
1190 :
1191 : return true;
1192 : }
1193 :
1194 : /* Here we check the constraints that are not per keyword. */
1195 :
1196 : static bool
1197 1673 : coro_function_valid_p (tree fndecl)
1198 : {
1199 1673 : location_t f_loc = DECL_SOURCE_LOCATION (fndecl);
1200 :
1201 : /* For cases where fundamental information cannot be found, e.g. the
1202 : coroutine traits are missing, we need to punt early. */
1203 1673 : if (!coro_promise_type_found_p (fndecl, f_loc))
1204 : return false;
1205 :
1206 : /* Since we think the function is a coroutine, that implies we parsed
1207 : a keyword that triggered this. Keywords check promise validity for
1208 : their context and thus the promise type should be known at this point. */
1209 1631 : if (get_coroutine_handle_type (fndecl) == NULL_TREE
1210 3247 : || get_coroutine_promise_type (fndecl) == NULL_TREE)
1211 15 : return false;
1212 :
1213 1616 : if (current_function_returns_value || current_function_returns_null)
1214 : {
1215 : /* TODO: record or extract positions of returns (and the first coro
1216 : keyword) so that we can add notes to the diagnostic about where
1217 : the bad keyword is and what made the function into a coro. */
1218 3 : error_at (f_loc, "a %<return%> statement is not allowed in coroutine;"
1219 : " did you mean %<co_return%>?");
1220 3 : return false;
1221 : }
1222 :
1223 : return true;
1224 : }
1225 :
1226 : enum suspend_point_kind {
1227 : CO_AWAIT_SUSPEND_POINT = 0,
1228 : CO_YIELD_SUSPEND_POINT,
1229 : INITIAL_SUSPEND_POINT,
1230 : FINAL_SUSPEND_POINT
1231 : };
1232 :
1233 : /* Helper function to build a named variable for the temps we use for each
1234 : await point. The root of the name is determined by SUSPEND_KIND, and
1235 : the variable is of type V_TYPE. The awaitable number is reset each time
1236 : we encounter a final suspend. */
1237 :
1238 : static tree
1239 4267 : get_awaitable_var (suspend_point_kind suspend_kind, tree v_type)
1240 : {
1241 4267 : auto cinfo = get_coroutine_info (current_function_decl);
1242 4267 : gcc_checking_assert (cinfo);
1243 4267 : char *buf;
1244 4267 : switch (suspend_kind)
1245 : {
1246 742 : default: buf = xasprintf ("Aw%d", cinfo->awaitable_number++); break;
1247 392 : case CO_YIELD_SUSPEND_POINT:
1248 392 : buf = xasprintf ("Yd%d", cinfo->awaitable_number++);
1249 392 : break;
1250 1574 : case INITIAL_SUSPEND_POINT: buf = xasprintf ("Is"); break;
1251 1559 : case FINAL_SUSPEND_POINT: buf = xasprintf ("Fs"); break;
1252 : }
1253 4267 : tree ret = get_identifier (buf);
1254 4267 : free (buf);
1255 4267 : ret = build_lang_decl (VAR_DECL, ret, v_type);
1256 4267 : DECL_ARTIFICIAL (ret) = true;
1257 4267 : return ret;
1258 : }
1259 :
1260 : /* Helpers to diagnose missing noexcept on final await expressions. */
1261 :
1262 : static bool
1263 6881 : coro_diagnose_throwing_fn (tree fndecl)
1264 : {
1265 6881 : if (!TYPE_NOTHROW_P (TREE_TYPE (fndecl)))
1266 : {
1267 21 : auto_diagnostic_group d;
1268 21 : location_t f_loc = cp_expr_loc_or_loc (fndecl,
1269 21 : DECL_SOURCE_LOCATION (fndecl));
1270 21 : error_at (f_loc, "the expression %qE is required to be non-throwing",
1271 : fndecl);
1272 21 : inform (f_loc, "must be declared with %<noexcept(true)%>");
1273 21 : return true;
1274 21 : }
1275 : return false;
1276 : }
1277 :
1278 : static bool
1279 1570 : coro_diagnose_throwing_final_aw_expr (tree expr)
1280 : {
1281 1570 : if (TREE_CODE (expr) == TARGET_EXPR)
1282 1567 : expr = TARGET_EXPR_INITIAL (expr);
1283 1570 : tree fn = NULL_TREE;
1284 1570 : if (TREE_CODE (expr) == CALL_EXPR)
1285 837 : fn = CALL_EXPR_FN (expr);
1286 733 : else if (TREE_CODE (expr) == AGGR_INIT_EXPR)
1287 733 : fn = AGGR_INIT_EXPR_FN (expr);
1288 0 : else if (TREE_CODE (expr) == CONSTRUCTOR)
1289 : return false;
1290 : else
1291 : {
1292 0 : gcc_checking_assert (0 && "unhandled expression type");
1293 : return false;
1294 : }
1295 1570 : fn = TREE_OPERAND (fn, 0);
1296 1570 : return coro_diagnose_throwing_fn (fn);
1297 : }
1298 :
1299 : /* Build a co_await suitable for later expansion. */
1300 :
1301 : tree
1302 148 : build_template_co_await_expr (location_t kw, tree type, tree expr, tree kind)
1303 : {
1304 148 : tree aw_expr = build5_loc (kw, CO_AWAIT_EXPR, type, expr,
1305 : NULL_TREE, NULL_TREE, NULL_TREE,
1306 : kind);
1307 148 : TREE_SIDE_EFFECTS (aw_expr) = true;
1308 148 : return aw_expr;
1309 : }
1310 :
1311 : /* Is EXPR an lvalue that will refer to the same object after a resume?
1312 :
1313 : This is close to asking tree_invariant_p of its address, but that doesn't
1314 : distinguish temporaries from other variables. */
1315 :
1316 : static bool
1317 4320 : is_stable_lvalue (tree expr)
1318 : {
1319 4320 : if (TREE_SIDE_EFFECTS (expr))
1320 : return false;
1321 :
1322 136 : for (; handled_component_p (expr);
1323 59 : expr = TREE_OPERAND (expr, 0))
1324 : {
1325 59 : if (TREE_CODE (expr) == ARRAY_REF
1326 59 : && !TREE_CONSTANT (TREE_OPERAND (expr, 1)))
1327 : return false;
1328 : }
1329 :
1330 77 : return (TREE_CODE (expr) == PARM_DECL
1331 77 : || (VAR_P (expr) && !is_local_temp (expr)));
1332 : }
1333 :
1334 : /* This performs [expr.await] bullet 3.3 and validates the interface obtained.
1335 : It is also used to build the initial and final suspend points.
1336 :
1337 : 'a', 'o' and 'e' are used as per the description in the section noted.
1338 :
1339 : A, the original yield/await expr, is found at source location LOC.
1340 :
1341 : We will be constructing a CO_AWAIT_EXPR for a suspend point of one of
1342 : the four suspend_point_kind kinds. This is indicated by SUSPEND_KIND.
1343 :
1344 : In the case that we're processing a template declaration, we can't save
1345 : actual awaiter expressions as the frame type will differ between
1346 : instantiations, but we can generate them to type-check them and compute the
1347 : resulting expression type. In those cases, we will return a
1348 : template-appropriate CO_AWAIT_EXPR and throw away the rest of the results.
1349 : Such an expression requires the original co_await operand unaltered. Pass
1350 : it as ORIG_OPERAND. If it is the same as 'a', you can pass NULL_TREE (the
1351 : default) to use 'a' as the value. */
1352 :
1353 : static tree
1354 4351 : build_co_await (location_t loc, tree a, suspend_point_kind suspend_kind,
1355 : tree orig_operand = NULL_TREE)
1356 : {
1357 4351 : if (orig_operand == NULL_TREE)
1358 3550 : orig_operand = a;
1359 :
1360 : /* Try and overload of operator co_await, .... */
1361 4351 : tree o;
1362 4351 : if (MAYBE_CLASS_TYPE_P (TREE_TYPE (a)))
1363 : {
1364 4335 : o = build_new_op (loc, CO_AWAIT_EXPR, LOOKUP_NORMAL, a, NULL_TREE,
1365 : NULL_TREE, NULL_TREE, NULL, tf_warning_or_error);
1366 : /* If no viable functions are found, o is a. */
1367 4335 : if (!o || o == error_mark_node)
1368 : o = a;
1369 135 : else if (flag_exceptions && suspend_kind == FINAL_SUSPEND_POINT)
1370 : {
1371 : /* We found an overload for co_await(), diagnose throwing cases. */
1372 21 : if (TREE_CODE (o) == TARGET_EXPR
1373 21 : && coro_diagnose_throwing_final_aw_expr (o))
1374 3 : return error_mark_node;
1375 :
1376 : /* We now know that the final suspend object is distinct from the
1377 : final awaiter, so check for a non-throwing DTOR where needed. */
1378 18 : if (tree dummy = cxx_maybe_build_cleanup (a, tf_none))
1379 : {
1380 15 : if (CONVERT_EXPR_P (dummy))
1381 0 : dummy = TREE_OPERAND (dummy, 0);
1382 15 : dummy = TREE_OPERAND (CALL_EXPR_FN (dummy), 0);
1383 15 : if (coro_diagnose_throwing_fn (dummy))
1384 3 : return error_mark_node;
1385 : }
1386 : }
1387 : }
1388 : else
1389 : o = a; /* This is most likely about to fail anyway. */
1390 :
1391 4345 : tree o_type = TREE_TYPE (o);
1392 4345 : if (o_type && !VOID_TYPE_P (o_type))
1393 4344 : o_type = complete_type_or_else (o_type, o);
1394 :
1395 4345 : if (!o_type || o_type == error_mark_node)
1396 9 : return error_mark_node;
1397 :
1398 4336 : if (TREE_CODE (o_type) != RECORD_TYPE)
1399 : {
1400 7 : if (suspend_kind == FINAL_SUSPEND_POINT)
1401 3 : error_at (loc, "%qs awaitable type %qT is not a structure",
1402 : "final_suspend()", o_type);
1403 4 : else if (suspend_kind == INITIAL_SUSPEND_POINT)
1404 3 : error_at (loc, "%qs awaitable type %qT is not a structure",
1405 : "initial_suspend()", o_type);
1406 : else
1407 1 : error_at (loc, "awaitable type %qT is not a structure", o_type);
1408 7 : return error_mark_node;
1409 : }
1410 :
1411 : /* Check for required awaitable members and their types. */
1412 4329 : tree awrd_meth
1413 4329 : = lookup_awaitable_member (o_type, coro_await_ready_identifier, loc);
1414 4329 : if (!awrd_meth || awrd_meth == error_mark_node)
1415 3 : return error_mark_node;
1416 4326 : tree awsp_meth
1417 4326 : = lookup_awaitable_member (o_type, coro_await_suspend_identifier, loc);
1418 4326 : if (!awsp_meth || awsp_meth == error_mark_node)
1419 3 : return error_mark_node;
1420 :
1421 : /* The type of the co_await is the return type of the awaitable's
1422 : await_resume, so we need to look that up. */
1423 4323 : tree awrs_meth
1424 4323 : = lookup_awaitable_member (o_type, coro_await_resume_identifier, loc);
1425 4323 : if (!awrs_meth || awrs_meth == error_mark_node)
1426 3 : return error_mark_node;
1427 :
1428 : /* [expr.await]/3.3 If o would be a prvalue, the temporary
1429 : materialization conversion ([conv.rval]) is applied. */
1430 4320 : if (!glvalue_p (o))
1431 4220 : o = get_target_expr (o, tf_warning_or_error);
1432 :
1433 : /* [expr.await]/3.4 e is an lvalue referring to the result of evaluating the
1434 : (possibly-converted) o.
1435 :
1436 : So, either reuse an existing stable lvalue such as a variable or
1437 : COMPONENT_REF thereof, or create a new a coroutine state frame variable
1438 : for the awaiter, since it must persist across suspension. */
1439 4320 : tree e_var = NULL_TREE;
1440 4320 : tree e_proxy = o;
1441 4320 : if (is_stable_lvalue (o))
1442 : o = NULL_TREE; /* Use the existing entity. */
1443 : else /* We need a non-temp var. */
1444 : {
1445 4267 : tree p_type = TREE_TYPE (o);
1446 4267 : tree o_a = o;
1447 4267 : if (glvalue_p (o))
1448 : {
1449 : /* Build a reference variable for a non-stable lvalue o. */
1450 47 : p_type = cp_build_reference_type (p_type, xvalue_p (o));
1451 47 : o_a = build_address (o);
1452 47 : o_a = cp_fold_convert (p_type, o_a);
1453 : }
1454 4267 : e_var = get_awaitable_var (suspend_kind, p_type);
1455 4267 : o = cp_build_init_expr (loc, e_var, o_a);
1456 4267 : e_proxy = convert_from_reference (e_var);
1457 : }
1458 :
1459 : /* I suppose we could check that this is contextually convertible to bool. */
1460 4320 : tree awrd_func = NULL_TREE;
1461 4320 : tree awrd_call
1462 4320 : = build_new_method_call (e_proxy, awrd_meth, NULL, NULL_TREE, LOOKUP_NORMAL,
1463 : &awrd_func, tf_warning_or_error);
1464 :
1465 4320 : if (!awrd_func || !awrd_call || awrd_call == error_mark_node)
1466 0 : return error_mark_node;
1467 :
1468 : /* The suspend method may return one of three types:
1469 : 1. void (no special action needed).
1470 : 2. bool (if true, we don't need to suspend).
1471 : 3. a coroutine handle, we execute the handle.resume() call. */
1472 4320 : tree awsp_func = NULL_TREE;
1473 4320 : tree h_proxy = get_coroutine_self_handle_proxy (current_function_decl);
1474 4320 : vec<tree, va_gc> *args = make_tree_vector_single (h_proxy);
1475 4320 : tree awsp_call
1476 4320 : = build_new_method_call (e_proxy, awsp_meth, &args, NULL_TREE,
1477 : LOOKUP_NORMAL, &awsp_func, tf_warning_or_error);
1478 :
1479 4320 : release_tree_vector (args);
1480 4320 : if (!awsp_func || !awsp_call || awsp_call == error_mark_node)
1481 0 : return error_mark_node;
1482 :
1483 4320 : bool ok = false;
1484 4320 : tree susp_return_type = TREE_TYPE (TREE_TYPE (awsp_func));
1485 4320 : if (same_type_p (susp_return_type, void_type_node))
1486 : ok = true;
1487 173 : else if (same_type_p (susp_return_type, boolean_type_node))
1488 : ok = true;
1489 117 : else if (TREE_CODE (susp_return_type) == RECORD_TYPE
1490 117 : && CLASS_TYPE_P (susp_return_type)
1491 234 : && CLASSTYPE_TEMPLATE_INFO (susp_return_type))
1492 : {
1493 114 : tree tt = CLASSTYPE_TI_TEMPLATE (susp_return_type);
1494 114 : if (tt == coro_handle_templ)
1495 : ok = true;
1496 : }
1497 :
1498 : if (!ok)
1499 : {
1500 3 : error_at (loc, "%<await_suspend%> must return %<void%>, %<bool%> or"
1501 : " a coroutine handle");
1502 3 : return error_mark_node;
1503 : }
1504 :
1505 : /* Finally, the type of e.await_resume() is the co_await's type. */
1506 4317 : tree awrs_func = NULL_TREE;
1507 4317 : tree awrs_call
1508 4317 : = build_new_method_call (e_proxy, awrs_meth, NULL, NULL_TREE, LOOKUP_NORMAL,
1509 : &awrs_func, tf_warning_or_error);
1510 :
1511 4317 : if (!awrs_func || !awrs_call || awrs_call == error_mark_node)
1512 0 : return error_mark_node;
1513 :
1514 4317 : if (flag_exceptions && suspend_kind == FINAL_SUSPEND_POINT)
1515 : {
1516 1537 : if (coro_diagnose_throwing_fn (awrd_func))
1517 3 : return error_mark_node;
1518 1534 : if (coro_diagnose_throwing_fn (awsp_func))
1519 3 : return error_mark_node;
1520 1531 : if (coro_diagnose_throwing_fn (awrs_func))
1521 3 : return error_mark_node;
1522 1528 : if (tree dummy = cxx_maybe_build_cleanup (e_var, tf_none))
1523 : {
1524 694 : if (CONVERT_EXPR_P (dummy))
1525 0 : dummy = TREE_OPERAND (dummy, 0);
1526 694 : dummy = TREE_OPERAND (CALL_EXPR_FN (dummy), 0);
1527 694 : if (coro_diagnose_throwing_fn (dummy))
1528 3 : return error_mark_node;
1529 : }
1530 : }
1531 :
1532 : /* We now have three call expressions, in terms of the promise, handle and
1533 : 'e' proxy expression. Save them in the await expression for later
1534 : expansion. */
1535 :
1536 4305 : tree awaiter_calls = make_tree_vec (3);
1537 4305 : TREE_VEC_ELT (awaiter_calls, 0) = awrd_call; /* await_ready(). */
1538 4305 : TREE_VEC_ELT (awaiter_calls, 1) = awsp_call; /* await_suspend(). */
1539 4305 : tree te = NULL_TREE;
1540 4305 : if (TREE_CODE (awrs_call) == TARGET_EXPR)
1541 : {
1542 36 : te = awrs_call;
1543 36 : awrs_call = TARGET_EXPR_INITIAL (awrs_call);
1544 : }
1545 4305 : TREE_VEC_ELT (awaiter_calls, 2) = awrs_call; /* await_resume(). */
1546 :
1547 4305 : if (e_var)
1548 4252 : e_proxy = e_var;
1549 :
1550 4305 : tree awrs_type = TREE_TYPE (TREE_TYPE (awrs_func));
1551 8610 : tree suspend_kind_cst = build_int_cst (integer_type_node,
1552 4305 : (int) suspend_kind);
1553 4305 : tree await_expr = build5_loc (loc, CO_AWAIT_EXPR,
1554 : awrs_type,
1555 : a, e_proxy, o, awaiter_calls,
1556 : suspend_kind_cst);
1557 4305 : TREE_SIDE_EFFECTS (await_expr) = true;
1558 4305 : if (te)
1559 : {
1560 36 : TREE_OPERAND (te, 1) = await_expr;
1561 36 : TREE_SIDE_EFFECTS (te) = true;
1562 36 : await_expr = te;
1563 : }
1564 4305 : SET_EXPR_LOCATION (await_expr, loc);
1565 :
1566 4305 : if (processing_template_decl)
1567 39 : return build_template_co_await_expr (loc, awrs_type, orig_operand,
1568 39 : suspend_kind_cst);
1569 4266 : return convert_from_reference (await_expr);
1570 : }
1571 :
1572 : /* Returns true iff EXPR or the TRAITS_CLASS, which should be a
1573 : coroutine_traits instance, are dependent. In those cases, we can't decide
1574 : what the types of our co_{await,yield,return} expressions are, so we defer
1575 : expansion entirely. */
1576 :
1577 : static bool
1578 3721 : coro_dependent_p (tree expr, tree traits_class)
1579 : {
1580 3721 : return type_dependent_expression_p (expr)
1581 3721 : || dependent_type_p (traits_class);
1582 : }
1583 :
1584 : tree
1585 949 : finish_co_await_expr (location_t kw, tree expr)
1586 : {
1587 949 : if (!expr || error_operand_p (expr))
1588 0 : return error_mark_node;
1589 :
1590 949 : if (cp_unevaluated_operand)
1591 : {
1592 3 : error_at (kw, "%qs cannot be used in an unevaluated context","co_await");
1593 3 : return error_mark_node;
1594 : }
1595 :
1596 946 : if (!coro_common_keyword_context_valid_p (current_function_decl, kw,
1597 : "co_await"))
1598 27 : return error_mark_node;
1599 :
1600 : /* The current function has now become a coroutine, if it wasn't already. */
1601 919 : DECL_COROUTINE_P (current_function_decl) = 1;
1602 :
1603 : /* This function will appear to have no return statement, even if it
1604 : is declared to return non-void (most likely). This is correct - we
1605 : synthesize the return for the ramp in the compiler. So suppress any
1606 : extraneous warnings during substitution. */
1607 919 : suppress_warning (current_function_decl, OPT_Wreturn_type);
1608 :
1609 : /* Prepare for coroutine transformations. */
1610 919 : if (!ensure_coro_initialized (kw))
1611 6 : return error_mark_node;
1612 :
1613 : /* Get our traits class. */
1614 913 : tree traits_class = coro_get_traits_class (current_function_decl, kw);
1615 :
1616 : /* Defer expansion when we are processing a template, unless the traits type
1617 : and expression would not be dependent. In the case that the types are
1618 : not dependent but we are processing a template declaration, we will do
1619 : most of the computation but throw away the results (except for the
1620 : await_resume type). Otherwise, if our co_await is type-dependent
1621 : (i.e. the promise type or operand type is dependent), we can't do much,
1622 : and just return early with a NULL_TREE type (indicating that we cannot
1623 : compute the type yet). */
1624 913 : if (coro_dependent_p (expr, traits_class))
1625 109 : return build_template_co_await_expr (kw, NULL_TREE, expr,
1626 109 : integer_zero_node);
1627 :
1628 : /* We must be able to look up the "await_transform" method in the scope of
1629 : the promise type, and obtain its return type. */
1630 804 : if (!coro_promise_type_found_p (current_function_decl, kw))
1631 3 : return error_mark_node;
1632 :
1633 : /* [expr.await] 3.2
1634 : The incoming cast expression might be transformed by a promise
1635 : 'await_transform()'. */
1636 801 : tree at_meth
1637 801 : = lookup_promise_method (current_function_decl,
1638 : coro_await_transform_identifier, kw,
1639 : /*musthave=*/false);
1640 801 : if (at_meth == error_mark_node)
1641 : return error_mark_node;
1642 :
1643 801 : tree a = expr;
1644 801 : if (at_meth)
1645 : {
1646 : /* try to build a = p.await_transform (e). */
1647 195 : vec<tree, va_gc> *args = make_tree_vector_single (expr);
1648 390 : a = build_new_method_call (get_coroutine_promise_proxy (
1649 : current_function_decl),
1650 : at_meth, &args, NULL_TREE, LOOKUP_NORMAL,
1651 : NULL, tf_warning_or_error);
1652 :
1653 : /* As I read the section.
1654 : We saw an await_transform method, so it's mandatory that we replace
1655 : expr with p.await_transform (expr), therefore if the method call fails
1656 : (presumably, we don't have suitable arguments) then this part of the
1657 : process fails. */
1658 195 : if (a == error_mark_node)
1659 0 : return error_mark_node;
1660 : }
1661 :
1662 : /* Now we want to build co_await a. */
1663 801 : return build_co_await (kw, a, CO_AWAIT_SUSPEND_POINT, expr);
1664 : }
1665 :
1666 : /* Take the EXPR given and attempt to build:
1667 : co_await p.yield_value (expr);
1668 : per [expr.yield] para 1. */
1669 :
1670 : tree
1671 1138 : finish_co_yield_expr (location_t kw, tree expr)
1672 : {
1673 1138 : if (!expr || error_operand_p (expr))
1674 0 : return error_mark_node;
1675 :
1676 1138 : if (cp_unevaluated_operand)
1677 : {
1678 3 : error_at (kw, "%qs cannot be used in an unevaluated context","co_yield");
1679 3 : return error_mark_node;
1680 : }
1681 :
1682 : /* Check the general requirements and simple syntax errors. */
1683 1135 : if (!coro_common_keyword_context_valid_p (current_function_decl, kw,
1684 : "co_yield"))
1685 27 : return error_mark_node;
1686 :
1687 : /* The current function has now become a coroutine, if it wasn't already. */
1688 1108 : DECL_COROUTINE_P (current_function_decl) = 1;
1689 :
1690 : /* This function will appear to have no return statement, even if it
1691 : is declared to return non-void (most likely). This is correct - we
1692 : synthesize the return for the ramp in the compiler. So suppress any
1693 : extraneous warnings during substitution. */
1694 1108 : suppress_warning (current_function_decl, OPT_Wreturn_type);
1695 :
1696 : /* Prepare for coroutine transformations. */
1697 1108 : if (!ensure_coro_initialized (kw))
1698 12 : return error_mark_node;
1699 :
1700 : /* Get our traits class. */
1701 1096 : tree traits_class = coro_get_traits_class (current_function_decl, kw);
1702 :
1703 : /* Defer expansion when we are processing a template; see note in
1704 : finish_co_await_expr. Also note that a yield is equivalent to
1705 :
1706 : co_await p.yield_value(EXPR)
1707 :
1708 : If either p or EXPR are type-dependent, then the whole expression is
1709 : certainly type-dependent, and we can't proceed. */
1710 1096 : if (coro_dependent_p (expr, traits_class))
1711 691 : return build2_loc (kw, CO_YIELD_EXPR, NULL_TREE, expr, NULL_TREE);
1712 :
1713 405 : if (!coro_promise_type_found_p (current_function_decl, kw))
1714 : /* We must be able to look up the "yield_value" method in the scope of
1715 : the promise type, and obtain its return type. */
1716 6 : return error_mark_node;
1717 :
1718 : /* [expr.yield] / 1
1719 : Let e be the operand of the yield-expression and p be an lvalue naming
1720 : the promise object of the enclosing coroutine, then the yield-expression
1721 : is equivalent to the expression co_await p.yield_value(e).
1722 : build p.yield_value(e): */
1723 399 : vec<tree, va_gc> *args = make_tree_vector_single (expr);
1724 399 : tree yield_call
1725 399 : = coro_build_promise_expression (current_function_decl, NULL,
1726 : coro_yield_value_identifier, kw,
1727 : &args, /*musthave=*/true);
1728 399 : release_tree_vector (args);
1729 :
1730 : /* Now build co_await p.yield_value (e).
1731 : Noting that for co_yield, there is no evaluation of any potential
1732 : promise transform_await(), so we call build_co_await directly. */
1733 :
1734 399 : tree op = build_co_await (kw, yield_call, CO_YIELD_SUSPEND_POINT);
1735 399 : if (op != error_mark_node)
1736 : {
1737 392 : if (REFERENCE_REF_P (op))
1738 0 : op = TREE_OPERAND (op, 0);
1739 : /* If the await expression is wrapped in a TARGET_EXPR, then transfer
1740 : that wrapper to the CO_YIELD_EXPR, since this is just a proxy for
1741 : its contained await. Otherwise, just build the CO_YIELD_EXPR. */
1742 392 : if (TREE_CODE (op) == TARGET_EXPR)
1743 : {
1744 3 : tree t = TARGET_EXPR_INITIAL (op);
1745 3 : t = build2_loc (kw, CO_YIELD_EXPR, TREE_TYPE (t), expr, t);
1746 3 : TARGET_EXPR_INITIAL (op) = t;
1747 : }
1748 : else
1749 389 : op = build2_loc (kw, CO_YIELD_EXPR, TREE_TYPE (op), expr, op);
1750 392 : TREE_SIDE_EFFECTS (op) = 1;
1751 392 : op = convert_from_reference (op);
1752 : }
1753 :
1754 : return op;
1755 : }
1756 :
1757 : /* Check and build a co_return statement.
1758 : First that it's valid to have a co_return keyword here.
1759 : If it is, then check and build the p.return_{void(),value(expr)}.
1760 : These are built against a proxy for the promise, which will be filled
1761 : in with the actual frame version when the function is transformed. */
1762 :
1763 : tree
1764 1763 : finish_co_return_stmt (location_t kw, tree expr)
1765 : {
1766 1763 : if (expr)
1767 1213 : STRIP_ANY_LOCATION_WRAPPER (expr);
1768 :
1769 1763 : if (error_operand_p (expr))
1770 0 : return error_mark_node;
1771 :
1772 : /* If it fails the following test, the function is not permitted to be a
1773 : coroutine, so the co_return statement is erroneous. */
1774 1763 : if (!coro_common_keyword_context_valid_p (current_function_decl, kw,
1775 : "co_return"))
1776 21 : return error_mark_node;
1777 :
1778 : /* The current function has now become a coroutine, if it wasn't
1779 : already. */
1780 1742 : DECL_COROUTINE_P (current_function_decl) = 1;
1781 :
1782 : /* This function will appear to have no return statement, even if it
1783 : is declared to return non-void (most likely). This is correct - we
1784 : synthesize the return for the ramp in the compiler. So suppress any
1785 : extraneous warnings during substitution. */
1786 1742 : suppress_warning (current_function_decl, OPT_Wreturn_type);
1787 :
1788 : /* Prepare for coroutine transformations. */
1789 1742 : if (!ensure_coro_initialized (kw))
1790 30 : return error_mark_node;
1791 :
1792 : /* Get our traits class. */
1793 1712 : tree traits_class = coro_get_traits_class (current_function_decl, kw);
1794 :
1795 1712 : if (processing_template_decl
1796 1712 : && check_for_bare_parameter_packs (expr))
1797 0 : return error_mark_node;
1798 :
1799 : /* Defer expansion when we must and are processing a template; see note in
1800 : finish_co_await_expr. */
1801 1712 : if (coro_dependent_p (expr, traits_class))
1802 : {
1803 : /* co_return expressions are always void type, regardless of the
1804 : expression type. */
1805 154 : expr = build2_loc (kw, CO_RETURN_EXPR, void_type_node,
1806 : expr, NULL_TREE);
1807 154 : expr = maybe_cleanup_point_expr_void (expr);
1808 154 : return add_stmt (expr);
1809 : }
1810 :
1811 1558 : if (!coro_promise_type_found_p (current_function_decl, kw))
1812 18 : return error_mark_node;
1813 :
1814 : /* Suppress -Wreturn-type for co_return, we need to check indirectly
1815 : whether the promise type has a suitable return_void/return_value. */
1816 1540 : suppress_warning (current_function_decl, OPT_Wreturn_type);
1817 :
1818 1540 : if (!processing_template_decl && warn_sequence_point)
1819 7 : verify_sequence_points (expr);
1820 :
1821 1540 : if (expr)
1822 : {
1823 : /* If we had an id-expression obfuscated by force_paren_expr, we need
1824 : to undo it so we can try to treat it as an rvalue below. */
1825 1047 : expr = maybe_undo_parenthesized_ref (expr);
1826 :
1827 1047 : if (error_operand_p (expr))
1828 0 : return error_mark_node;
1829 : }
1830 :
1831 : /* If the promise object doesn't have the correct return call then
1832 : there's a mis-match between the co_return <expr> and this. */
1833 493 : tree co_ret_call = error_mark_node;
1834 1047 : if (expr == NULL_TREE || VOID_TYPE_P (TREE_TYPE (expr)))
1835 503 : co_ret_call
1836 503 : = get_coroutine_return_void_expr (current_function_decl, kw, true);
1837 : else
1838 : {
1839 : /* [class.copy.elision] / 3.
1840 : An implicitly movable entity is a variable of automatic storage
1841 : duration that is either a non-volatile object or an rvalue reference
1842 : to a non-volatile object type. For such objects in the context of
1843 : the co_return, the overload resolution should be carried out first
1844 : treating the object as an rvalue, if that fails, then we fall back
1845 : to regular overload resolution. */
1846 :
1847 1037 : tree arg = expr;
1848 1037 : if (tree moved = treat_lvalue_as_rvalue_p (expr, /*return*/true))
1849 247 : arg = moved;
1850 :
1851 1037 : releasing_vec args = make_tree_vector_single (arg);
1852 1037 : co_ret_call
1853 1037 : = coro_build_promise_expression (current_function_decl, NULL,
1854 : coro_return_value_identifier, kw,
1855 : &args, /*musthave=*/true);
1856 1037 : }
1857 :
1858 : /* Makes no sense for a co-routine really. */
1859 1540 : if (TREE_THIS_VOLATILE (current_function_decl))
1860 0 : warning_at (kw, 0,
1861 : "function declared %<noreturn%> has a"
1862 : " %<co_return%> statement");
1863 :
1864 1540 : expr = build2_loc (kw, CO_RETURN_EXPR, void_type_node, expr, co_ret_call);
1865 1540 : expr = maybe_cleanup_point_expr_void (expr);
1866 1540 : return add_stmt (expr);
1867 : }
1868 :
1869 : /* We need to validate the arguments to __builtin_coro_promise, since the
1870 : second two must be constant, and the builtins machinery doesn't seem to
1871 : deal with that properly. */
1872 :
1873 : tree
1874 8737945 : coro_validate_builtin_call (tree call, tsubst_flags_t)
1875 : {
1876 8737945 : tree fn = TREE_OPERAND (CALL_EXPR_FN (call), 0);
1877 :
1878 8737945 : gcc_checking_assert (DECL_BUILT_IN_CLASS (fn) == BUILT_IN_NORMAL);
1879 8737945 : switch (DECL_FUNCTION_CODE (fn))
1880 : {
1881 : default:
1882 : return call;
1883 :
1884 22645 : case BUILT_IN_CORO_PROMISE:
1885 22645 : {
1886 : /* Argument 0 is already checked by the normal built-in machinery
1887 : Argument 1 must be a constant of size type. It probably makes
1888 : little sense if it's not a power of 2, but that isn't specified
1889 : formally. */
1890 22645 : tree arg = CALL_EXPR_ARG (call, 1);
1891 22645 : location_t loc = EXPR_LOCATION (arg);
1892 :
1893 : /* We expect alignof expressions in templates. */
1894 22645 : if (TREE_CODE (arg) == ALIGNOF_EXPR)
1895 : ;
1896 1877 : else if (!TREE_CONSTANT (arg))
1897 : {
1898 0 : error_at (loc, "the align argument to %<__builtin_coro_promise%>"
1899 : " must be a constant");
1900 0 : return error_mark_node;
1901 : }
1902 : /* Argument 2 is the direction - to / from handle address to promise
1903 : address. */
1904 22645 : arg = CALL_EXPR_ARG (call, 2);
1905 22645 : loc = EXPR_LOCATION (arg);
1906 22645 : if (!TREE_CONSTANT (arg))
1907 : {
1908 0 : error_at (loc, "the direction argument to"
1909 : " %<__builtin_coro_promise%> must be a constant");
1910 0 : return error_mark_node;
1911 : }
1912 : return call;
1913 : break;
1914 : }
1915 : }
1916 : }
1917 :
1918 : /* ================= Morph and Expand. =================
1919 :
1920 : The entry point here is morph_fn_to_coro () which is called from
1921 : finish_function () when we have completed any template expansion.
1922 :
1923 : This is preceded by helper functions that implement the phases below.
1924 :
1925 : The process proceeds in four phases.
1926 :
1927 : A Initial framing.
1928 : The user's function body is wrapped in the initial and final suspend
1929 : points and we begin building the coroutine frame.
1930 : We build empty decls for the actor and destroyer functions at this
1931 : time too.
1932 : When exceptions are enabled, the user's function body will also be
1933 : wrapped in a try-catch block with the catch invoking the promise
1934 : class 'unhandled_exception' method.
1935 :
1936 : B Analysis.
1937 : The user's function body is analyzed to determine the suspend points,
1938 : if any, and to capture local variables that might persist across such
1939 : suspensions. In most cases, it is not necessary to capture compiler
1940 : temporaries, since the tree-lowering nests the suspensions correctly.
1941 : However, in the case of a captured reference, there is a lifetime
1942 : extension to the end of the full expression - which can mean across a
1943 : suspend point in which case it must be promoted to a frame variable.
1944 :
1945 : At the conclusion of analysis, we have a conservative frame layout and
1946 : maps of the local variables to their frame entry points.
1947 :
1948 : C Build the ramp function.
1949 : Carry out the allocation for the coroutine frame (NOTE; the actual size
1950 : computation is deferred until late in the middle end to allow for future
1951 : optimizations that will be allowed to elide unused frame entries).
1952 : We build the return object.
1953 :
1954 : D Build and expand the actor and destroyer function bodies.
1955 : The destroyer is a trivial shim that sets a bit to indicate that the
1956 : destroy dispatcher should be used and then calls into the actor.
1957 :
1958 : The actor function is the implementation of the user's state machine.
1959 : The current suspend point is noted in an index.
1960 : Each suspend point is encoded as a pair of internal functions, one in
1961 : the relevant dispatcher, and one representing the suspend point.
1962 :
1963 : During this process, the user's local variables and the proxies for the
1964 : self-handle and the promise class instance are re-written to their
1965 : coroutine frame equivalents.
1966 :
1967 : The complete bodies for the ramp, actor and destroy function are passed
1968 : back to finish_function for folding and gimplification. */
1969 :
1970 : /* Helper to build a coroutine state frame access expression
1971 : CORO_FP is a frame pointer
1972 : MEMBER_ID is an identifier for a frame field
1973 : PRESERVE_REF is true, the expression returned will have REFERENCE_TYPE if
1974 : the MEMBER does.
1975 : COMPLAIN is passed to the underlying functions. */
1976 :
1977 : static tree
1978 36090 : coro_build_frame_access_expr (tree coro_ref, tree member_id, bool preserve_ref,
1979 : tsubst_flags_t complain)
1980 : {
1981 36090 : gcc_checking_assert (INDIRECT_REF_P (coro_ref));
1982 36090 : tree fr_type = TREE_TYPE (coro_ref);
1983 36090 : tree mb = lookup_member (fr_type, member_id, /*protect=*/1, /*want_type=*/0,
1984 : complain);
1985 36090 : if (!mb || mb == error_mark_node)
1986 0 : return error_mark_node;
1987 36090 : tree expr
1988 36090 : = build_class_member_access_expr (coro_ref, mb, NULL_TREE,
1989 : preserve_ref, complain);
1990 36090 : return expr;
1991 : }
1992 :
1993 : /* Helpers to build an artificial var, with location LOC, NAME and TYPE, in
1994 : CTX, and with initializer INIT. */
1995 :
1996 : static tree
1997 23958 : coro_build_artificial_var (location_t loc, tree name, tree type, tree ctx,
1998 : tree init)
1999 : {
2000 23958 : tree res = build_lang_decl (VAR_DECL, name, type);
2001 23958 : DECL_SOURCE_LOCATION (res) = loc;
2002 23958 : DECL_CONTEXT (res) = ctx;
2003 23958 : DECL_ARTIFICIAL (res) = true;
2004 23958 : DECL_INITIAL (res) = init;
2005 23958 : return res;
2006 : }
2007 :
2008 : /* As above, except allowing the name to be a string. */
2009 :
2010 : static tree
2011 3182 : coro_build_artificial_var (location_t loc, const char *name, tree type,
2012 : tree ctx, tree init)
2013 : {
2014 3182 : return coro_build_artificial_var (loc, get_identifier (name),
2015 3182 : type, ctx, init);
2016 : }
2017 :
2018 : /* As for coro_build_artificial_var, except that we push this decl into
2019 : the current binding scope and add the decl_expr. */
2020 :
2021 : static tree
2022 1575 : coro_build_and_push_artificial_var (location_t loc, const char *name,
2023 : tree type, tree ctx, tree init)
2024 : {
2025 1575 : tree v = coro_build_artificial_var (loc, name, type, ctx, init);
2026 1575 : v = pushdecl (v);
2027 1575 : add_decl_expr (v);
2028 1575 : return v;
2029 : }
2030 :
2031 : /* Build a var NAME of TYPE in CTX and with INIT; add a DECL_VALUE_EXPR that
2032 : refers to BASE.FIELD. */
2033 :
2034 : static tree
2035 9549 : coro_build_artificial_var_with_dve (location_t loc, tree name, tree type,
2036 : tree ctx, tree init, tree base,
2037 : tree field = NULL_TREE)
2038 : {
2039 9549 : tree v = coro_build_artificial_var (loc, name, type, ctx, init);
2040 9549 : if (field == NULL_TREE)
2041 9549 : field = name;
2042 9549 : tree dve = coro_build_frame_access_expr (base, field, true,
2043 : tf_warning_or_error);
2044 9549 : SET_DECL_VALUE_EXPR (v, dve);
2045 9549 : DECL_HAS_VALUE_EXPR_P (v) = true;
2046 9549 : return v;
2047 : }
2048 :
2049 : /* As for coro_build_artificial_var_with_dve, but push into the current binding
2050 : scope and add the decl_expr. */
2051 :
2052 : static tree
2053 9549 : coro_build_and_push_artificial_var_with_dve (location_t loc, tree name,
2054 : tree type, tree ctx, tree init,
2055 : tree base, tree field = NULL_TREE)
2056 : {
2057 9549 : tree v = coro_build_artificial_var_with_dve (loc, name, type, ctx, init,
2058 : base, field);
2059 9549 : v = pushdecl (v);
2060 9549 : add_decl_expr (v);
2061 9549 : return v;
2062 : }
2063 :
2064 : /* 2. Create a named label in the specified context. */
2065 :
2066 : static tree
2067 17977 : create_named_label_with_ctx (location_t loc, const char *name, tree ctx)
2068 : {
2069 17977 : tree lab_id = get_identifier (name);
2070 17977 : tree lab = define_label (loc, lab_id);
2071 17977 : DECL_CONTEXT (lab) = ctx;
2072 17977 : DECL_ARTIFICIAL (lab) = true;
2073 17977 : TREE_USED (lab) = true;
2074 17977 : return lab;
2075 : }
2076 :
2077 : struct proxy_replace
2078 : {
2079 : tree from, to;
2080 : };
2081 :
2082 : static tree
2083 10903 : replace_proxy (tree *here, int *do_subtree, void *d)
2084 : {
2085 10903 : proxy_replace *data = (proxy_replace *) d;
2086 :
2087 10903 : if (*here == data->from)
2088 : {
2089 198 : *here = data->to;
2090 198 : *do_subtree = 0;
2091 : }
2092 : else
2093 10705 : *do_subtree = 1;
2094 10903 : return NULL_TREE;
2095 : }
2096 :
2097 : /* Support for expansion of co_await statements. */
2098 :
2099 : struct coro_aw_data
2100 : {
2101 : tree actor_fn; /* Decl for context. */
2102 : tree coro_fp; /* Frame pointer var. */
2103 : tree resume_idx; /* This is the index var in the frame. */
2104 : tree i_a_r_c; /* initial suspend await_resume() was called if true. */
2105 : tree cleanup; /* This is where to go once we complete local destroy. */
2106 : tree cororet; /* This is where to go if we suspend. */
2107 : tree corocont; /* This is where to go if we continue. */
2108 : tree dispatch; /* This is where we go if we restart the dispatch. */
2109 : tree conthand; /* This is the handle for a continuation. */
2110 : tree handle_type; /* Handle type for this coroutine... */
2111 : tree hfa_m; /* ... and handle.from_address() for this. */
2112 : unsigned index; /* This is our current resume index. */
2113 : };
2114 :
2115 : /* Lightweight search for the first await expression in tree-walk order.
2116 : returns:
2117 : The first await expression found in STMT.
2118 : NULL_TREE if there are none.
2119 : So can be used to determine if the statement needs to be processed for
2120 : awaits. */
2121 :
2122 : static tree
2123 416434 : co_await_find_in_subtree (tree *stmt, int *, void *d)
2124 : {
2125 416434 : tree **p = (tree **) d;
2126 416434 : if (TREE_CODE (*stmt) == CO_AWAIT_EXPR)
2127 : {
2128 4203 : *p = stmt;
2129 4203 : return *stmt;
2130 : }
2131 : return NULL_TREE;
2132 : }
2133 :
2134 : /* Starting with a statement:
2135 :
2136 : stmt => some tree containing one or more await expressions.
2137 :
2138 : We replace the statement with:
2139 : <STATEMENT_LIST> {
2140 : initialize awaitable
2141 : if (!ready)
2142 : {
2143 : suspension context.
2144 : }
2145 : resume:
2146 : revised statement with one await expression rewritten to its
2147 : await_resume() return value.
2148 : }
2149 :
2150 : We then recurse into the initializer and the revised statement
2151 : repeating this replacement until there are no more await expressions
2152 : in either. */
2153 :
2154 : static tree *
2155 4203 : expand_one_await_expression (tree *expr, tree *await_expr, void *d)
2156 : {
2157 4203 : coro_aw_data *data = (coro_aw_data *) d;
2158 :
2159 4203 : tree saved_statement = *expr;
2160 4203 : tree saved_co_await = *await_expr;
2161 :
2162 4203 : tree actor = data->actor_fn;
2163 4203 : location_t loc = EXPR_LOCATION (*expr);
2164 4203 : tree var = TREE_OPERAND (saved_co_await, 1); /* frame slot. */
2165 4203 : tree init_expr = TREE_OPERAND (saved_co_await, 2); /* initializer. */
2166 4203 : tree awaiter_calls = TREE_OPERAND (saved_co_await, 3);
2167 :
2168 4203 : tree source = TREE_OPERAND (saved_co_await, 4);
2169 4203 : bool is_final
2170 4203 : = (source && TREE_INT_CST_LOW (source) == (int) FINAL_SUSPEND_POINT);
2171 4203 : bool is_initial
2172 4203 : = (source && TREE_INT_CST_LOW (source) == (int) INITIAL_SUSPEND_POINT);
2173 :
2174 : /* Build labels for the destinations of the control flow when we are resuming
2175 : or destroying. */
2176 4203 : int resume_point = data->index;
2177 4203 : char *buf = xasprintf ("destroy.%d", resume_point);
2178 4203 : tree destroy_label = create_named_label_with_ctx (loc, buf, actor);
2179 4203 : free (buf);
2180 4203 : buf = xasprintf ("resume.%d", resume_point);
2181 4203 : tree resume_label = create_named_label_with_ctx (loc, buf, actor);
2182 4203 : free (buf);
2183 :
2184 : /* This will contain our expanded expression and replace the original
2185 : expression. */
2186 4203 : tree stmt_list = push_stmt_list ();
2187 4203 : tree *await_init = NULL;
2188 :
2189 4203 : bool needs_dtor = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (var));
2190 4203 : if (!init_expr)
2191 : needs_dtor = false; /* No need, the var's lifetime is managed elsewhere. */
2192 : else
2193 : {
2194 0 : finish_expr_stmt (init_expr);
2195 : /* We have an initializer, which might itself contain await exprs. */
2196 0 : await_init = tsi_stmt_ptr (tsi_last (stmt_list));
2197 : }
2198 :
2199 : /* Use the await_ready() call to test if we need to suspend. */
2200 4203 : tree ready_cond = TREE_VEC_ELT (awaiter_calls, 0); /* await_ready(). */
2201 :
2202 : /* We will resume (or continue) at the following index. */
2203 4203 : tree resume_idx = build_int_cst (short_unsigned_type_node, data->index);
2204 4203 : tree r = cp_build_init_expr (data->resume_idx, resume_idx);
2205 4203 : finish_expr_stmt (r);
2206 :
2207 : /* Convert to bool, if necessary. */
2208 4203 : if (TREE_CODE (TREE_TYPE (ready_cond)) != BOOLEAN_TYPE)
2209 6 : ready_cond = cp_convert (boolean_type_node, ready_cond,
2210 : tf_warning_or_error);
2211 4203 : tree susp_if = begin_if_stmt ();
2212 : /* Be aggressive in folding here, since there are a significant number of
2213 : cases where the ready condition is constant. */
2214 4203 : ready_cond = invert_truthvalue_loc (loc, ready_cond);
2215 4203 : finish_if_stmt_cond (ready_cond, susp_if);
2216 :
2217 : /* Find out what we have to do with the awaiter's suspend method.
2218 : [expr.await]
2219 : (5.1) If the result of await-ready is false, the coroutine is considered
2220 : suspended. Then:
2221 : (5.1.1) If the type of await-suspend is std::coroutine_handle<Z>,
2222 : await-suspend.resume() is evaluated.
2223 : (5.1.2) if the type of await-suspend is bool, await-suspend is evaluated,
2224 : and the coroutine is resumed if the result is false.
2225 : (5.1.3) Otherwise, await-suspend is evaluated. */
2226 :
2227 4203 : tree suspend = TREE_VEC_ELT (awaiter_calls, 1); /* await_suspend(). */
2228 4203 : tree susp_type = TREE_TYPE (suspend);
2229 4203 : tree susp_call = suspend;
2230 4203 : if (TREE_CODE (suspend) == TARGET_EXPR)
2231 114 : susp_call = TARGET_EXPR_INITIAL (suspend);
2232 4203 : gcc_checking_assert (TREE_CODE (susp_call) == CALL_EXPR);
2233 4203 : tree dummy_ch = build_dummy_object (data->handle_type);
2234 4203 : r = fold_convert (build_pointer_type (void_type_node), data->coro_fp);
2235 4203 : vec<tree, va_gc> *args = make_tree_vector_single (r);
2236 4203 : tree hfa = cp_fold_rvalue (
2237 : build_new_method_call (dummy_ch, data->hfa_m, &args, NULL_TREE,
2238 : LOOKUP_NORMAL, NULL, tf_warning_or_error));
2239 4203 : release_tree_vector (args);
2240 4203 : CALL_EXPR_ARG (susp_call, call_expr_nargs (susp_call) - 1) = hfa;
2241 :
2242 4203 : bool is_cont = false;
2243 : /* NOTE: final suspend can't resume; the "resume" label in that case
2244 : corresponds to implicit destruction. */
2245 4203 : if (VOID_TYPE_P (susp_type))
2246 : /* Void return - just proceed to suspend. */
2247 4054 : finish_expr_stmt (suspend);
2248 149 : else if (TREE_CODE (susp_type) == BOOLEAN_TYPE)
2249 : {
2250 : /* Boolean return, "continue" if the call returns false. */
2251 35 : tree restart_if = begin_if_stmt ();
2252 35 : suspend = invert_truthvalue_loc (loc, suspend);
2253 35 : finish_if_stmt_cond (suspend, restart_if);
2254 : /* Resume - so restart the dispatcher, since we do not know if this
2255 : coroutine was already resumed from within await_suspend. We must
2256 : exit this scope without cleanups. */
2257 35 : r = build_call_expr_internal_loc (loc, IFN_CO_SUSPN, void_type_node, 1,
2258 : build_address (data->dispatch));
2259 : /* This will eventually expand to 'goto coro.restart.dispatch'. */
2260 35 : finish_expr_stmt (r);
2261 35 : finish_then_clause (restart_if);
2262 35 : finish_if_stmt (restart_if);
2263 : }
2264 : else
2265 : {
2266 : /* Handle return, save it to the continuation. */
2267 114 : r = suspend;
2268 114 : if (!same_type_ignoring_top_level_qualifiers_p (susp_type,
2269 : void_coro_handle_type))
2270 16 : r = build1_loc (loc, VIEW_CONVERT_EXPR, void_coro_handle_type, r);
2271 114 : r = cp_build_init_expr (loc, data->conthand, r);
2272 114 : finish_expr_stmt (r);
2273 114 : is_cont = true;
2274 : }
2275 :
2276 4203 : tree d_l = build_address (destroy_label);
2277 4203 : tree r_l = build_address (resume_label);
2278 4203 : tree susp = build_address (data->cororet);
2279 4203 : tree cont = build_address (data->corocont);
2280 6880 : tree final_susp = build_int_cst (integer_type_node, is_final ? 1 : 0);
2281 :
2282 4203 : resume_idx = build_int_cst (integer_type_node, data->index);
2283 :
2284 4203 : tree sw = begin_switch_stmt ();
2285 :
2286 4203 : r = build_call_expr_internal_loc (loc, IFN_CO_YIELD, integer_type_node, 5,
2287 : resume_idx, final_susp, r_l, d_l,
2288 : data->coro_fp);
2289 4203 : finish_switch_cond (r, sw);
2290 4203 : finish_case_label (loc, integer_zero_node, NULL_TREE); /* case 0: */
2291 : /* Implement the suspend, a scope exit without clean ups. */
2292 8292 : r = build_call_expr_internal_loc (loc, IFN_CO_SUSPN, void_type_node, 1,
2293 : is_cont ? cont : susp);
2294 4203 : finish_expr_stmt (r); /* This will eventually expand to 'goto return'. */
2295 4203 : finish_case_label (loc, integer_one_node, NULL_TREE); /* case 1: */
2296 4203 : add_stmt (build_stmt (loc, GOTO_EXPR, resume_label)); /* goto resume; */
2297 4203 : finish_case_label (loc, NULL_TREE, NULL_TREE); /* default:; */
2298 4203 : add_stmt (build_stmt (loc, GOTO_EXPR, destroy_label)); /* goto destroy; */
2299 :
2300 4203 : finish_switch_stmt (sw);
2301 4203 : add_stmt (build_stmt (loc, LABEL_EXPR, destroy_label));
2302 4203 : if (needs_dtor)
2303 0 : finish_expr_stmt (build_cleanup (var));
2304 4203 : add_stmt (build_stmt (loc, GOTO_EXPR, data->cleanup));
2305 :
2306 4203 : finish_then_clause (susp_if);
2307 4203 : finish_if_stmt (susp_if);
2308 :
2309 : /* Resume point. */
2310 4203 : add_stmt (build_stmt (loc, LABEL_EXPR, resume_label));
2311 :
2312 4203 : if (is_initial && data->i_a_r_c)
2313 : {
2314 1531 : r = cp_build_modify_expr (loc, data->i_a_r_c, NOP_EXPR, boolean_true_node,
2315 : tf_warning_or_error);
2316 1531 : finish_expr_stmt (r);
2317 : }
2318 :
2319 : /* This will produce the value (if one is provided) from the co_await
2320 : expression. */
2321 4203 : tree resume_call = TREE_VEC_ELT (awaiter_calls, 2); /* await_resume(). */
2322 4203 : if (REFERENCE_REF_P (resume_call))
2323 : /* Sink to await_resume call_expr. */
2324 71 : resume_call = TREE_OPERAND (resume_call, 0);
2325 :
2326 4203 : *await_expr = resume_call; /* Replace the co_await expr with its result. */
2327 4203 : append_to_statement_list_force (saved_statement, &stmt_list);
2328 : /* Get a pointer to the revised statement. */
2329 4203 : tree *revised = tsi_stmt_ptr (tsi_last (stmt_list));
2330 4203 : if (needs_dtor)
2331 0 : finish_expr_stmt (build_cleanup (var));
2332 4203 : data->index += 2;
2333 :
2334 : /* Replace the original expression with the expansion. */
2335 4203 : *expr = pop_stmt_list (stmt_list);
2336 :
2337 : /* Now, if the awaitable had an initializer, expand any awaits that might
2338 : be embedded in it. */
2339 4203 : tree *aw_expr_ptr;
2340 4203 : if (await_init &&
2341 0 : cp_walk_tree (await_init, co_await_find_in_subtree, &aw_expr_ptr, NULL))
2342 0 : expand_one_await_expression (await_init, aw_expr_ptr, d);
2343 :
2344 : /* Expand any more await expressions in the original statement. */
2345 4203 : if (cp_walk_tree (revised, co_await_find_in_subtree, &aw_expr_ptr, NULL))
2346 14 : expand_one_await_expression (revised, aw_expr_ptr, d);
2347 :
2348 4203 : return NULL;
2349 : }
2350 :
2351 : /* Check to see if a statement contains at least one await expression, if
2352 : so, then process that. */
2353 :
2354 : static tree
2355 55190 : process_one_statement (tree *stmt, void *d)
2356 : {
2357 55190 : tree *aw_expr_ptr;
2358 55190 : if (cp_walk_tree (stmt, co_await_find_in_subtree, &aw_expr_ptr, NULL))
2359 4189 : expand_one_await_expression (stmt, aw_expr_ptr, d);
2360 55190 : return NULL_TREE;
2361 : }
2362 :
2363 : static tree
2364 395627 : await_statement_expander (tree *stmt, int *do_subtree, void *d)
2365 : {
2366 395627 : tree res = NULL_TREE;
2367 :
2368 : /* Process a statement at a time. */
2369 395627 : if (STATEMENT_CLASS_P (*stmt)
2370 310388 : || TREE_CODE (*stmt) == BIND_EXPR
2371 302773 : || TREE_CODE (*stmt) == CLEANUP_POINT_EXPR)
2372 : return NULL_TREE; /* Just process the sub-trees. */
2373 263297 : else if (TREE_CODE (*stmt) == STATEMENT_LIST)
2374 : {
2375 141504 : for (tree &s : tsi_range (*stmt))
2376 : {
2377 121604 : res = cp_walk_tree (&s, await_statement_expander,
2378 : d, NULL);
2379 121604 : if (res)
2380 395627 : return res;
2381 : }
2382 19900 : *do_subtree = 0; /* Done subtrees. */
2383 : }
2384 243397 : else if (EXPR_P (*stmt))
2385 : {
2386 55190 : process_one_statement (stmt, d);
2387 55190 : *do_subtree = 0; /* Done subtrees. */
2388 : }
2389 :
2390 : /* Continue statement walk, where required. */
2391 : return res;
2392 : }
2393 :
2394 : struct await_xform_data
2395 : {
2396 : tree actor_fn; /* Decl for context. */
2397 : tree actor_frame;
2398 : hash_map<tree, suspend_point_info> *suspend_points;
2399 : };
2400 :
2401 : /* When we built the await expressions, we didn't know the coro frame
2402 : layout, therefore no idea where to find the promise or where to put
2403 : the awaitables. Now we know these things, fill them in. */
2404 :
2405 : static tree
2406 4203 : transform_await_expr (tree await_expr, await_xform_data *xform)
2407 : {
2408 4203 : suspend_point_info *si = xform->suspend_points->get (await_expr);
2409 4203 : location_t loc = EXPR_LOCATION (await_expr);
2410 4203 : if (!si)
2411 : {
2412 0 : error_at (loc, "no suspend point info for %qD", await_expr);
2413 0 : return error_mark_node;
2414 : }
2415 :
2416 : /* So, on entry, we have:
2417 : in : CO_AWAIT_EXPR (a, e_proxy, o, awr_call_vector, mode)
2418 : We no longer need a [it had diagnostic value, maybe?]
2419 : We need to replace the e_proxy in the awr_call. */
2420 :
2421 : /* If we have a frame var for the awaitable, get a reference to it. */
2422 4203 : proxy_replace data;
2423 4203 : if (si->await_field_id)
2424 : {
2425 0 : tree as
2426 0 : = coro_build_frame_access_expr (xform->actor_frame, si->await_field_id,
2427 : true, tf_warning_or_error);
2428 : /* Replace references to the instance proxy with the frame entry now
2429 : computed. */
2430 0 : data.from = TREE_OPERAND (await_expr, 1);
2431 0 : data.to = as;
2432 0 : cp_walk_tree (&await_expr, replace_proxy, &data, NULL);
2433 :
2434 : /* .. and replace. */
2435 0 : TREE_OPERAND (await_expr, 1) = as;
2436 : }
2437 :
2438 4203 : return await_expr;
2439 : }
2440 :
2441 : /* A wrapper for the transform_await_expr function so that it can be a
2442 : callback from cp_walk_tree. */
2443 :
2444 : static tree
2445 359477 : transform_await_wrapper (tree *stmt, int *do_subtree, void *d)
2446 : {
2447 : /* Set actor function as new DECL_CONTEXT of label_decl. */
2448 359477 : struct await_xform_data *xform = (struct await_xform_data *) d;
2449 359477 : if (TREE_CODE (*stmt) == LABEL_DECL
2450 359477 : && DECL_CONTEXT (*stmt) != xform->actor_fn)
2451 1641 : DECL_CONTEXT (*stmt) = xform->actor_fn;
2452 :
2453 : /* We should have already lowered co_yields to their co_await. */
2454 359477 : gcc_checking_assert (TREE_CODE (*stmt) != CO_YIELD_EXPR);
2455 359477 : if (TREE_CODE (*stmt) != CO_AWAIT_EXPR)
2456 : return NULL_TREE;
2457 :
2458 4203 : tree await_expr = *stmt;
2459 4203 : *stmt = transform_await_expr (await_expr, xform);
2460 4203 : if (*stmt == error_mark_node)
2461 0 : *do_subtree = 0;
2462 : return NULL_TREE;
2463 : }
2464 :
2465 : /* For figuring out what local variable usage we have. */
2466 : struct local_vars_transform
2467 : {
2468 : tree context;
2469 : tree actor_frame;
2470 : tree coro_frame_type;
2471 : location_t loc;
2472 : hash_map<tree, local_var_info> *local_var_uses;
2473 : };
2474 :
2475 : static tree
2476 564065 : transform_local_var_uses (tree *stmt, int *do_subtree, void *d)
2477 : {
2478 564065 : local_vars_transform *lvd = (local_vars_transform *) d;
2479 :
2480 : /* For each var in this bind expr (that has a frame id, which means it was
2481 : accessed), build a frame reference and add it as the DECL_VALUE_EXPR. */
2482 :
2483 564065 : if (TREE_CODE (*stmt) == BIND_EXPR)
2484 : {
2485 7621 : tree lvar;
2486 25295 : for (lvar = BIND_EXPR_VARS (*stmt); lvar != NULL;
2487 17674 : lvar = DECL_CHAIN (lvar))
2488 : {
2489 17674 : bool existed;
2490 17674 : local_var_info &local_var
2491 17674 : = lvd->local_var_uses->get_or_insert (lvar, &existed);
2492 17674 : gcc_checking_assert (existed);
2493 :
2494 : /* Re-write the variable's context to be in the actor func. */
2495 17674 : DECL_CONTEXT (lvar) = lvd->context;
2496 :
2497 : /* For capture proxies, this could include the decl value expr. */
2498 17674 : if (local_var.is_lambda_capture || local_var.has_value_expr_p)
2499 171 : continue; /* No frame entry for this. */
2500 :
2501 : /* TODO: implement selective generation of fields when vars are
2502 : known not-used. */
2503 17558 : if (local_var.field_id == NULL_TREE)
2504 55 : continue; /* Wasn't used. */
2505 17503 : tree fld_idx
2506 17503 : = coro_build_frame_access_expr (lvd->actor_frame,
2507 : local_var.field_id, true,
2508 : tf_warning_or_error);
2509 17503 : local_var.field_idx = fld_idx;
2510 17503 : SET_DECL_VALUE_EXPR (lvar, fld_idx);
2511 17503 : DECL_HAS_VALUE_EXPR_P (lvar) = true;
2512 : }
2513 7621 : cp_walk_tree (&BIND_EXPR_BODY (*stmt), transform_local_var_uses, d, NULL);
2514 7621 : *do_subtree = 0; /* We've done the body already. */
2515 7621 : return NULL_TREE;
2516 : }
2517 : return NULL_TREE;
2518 : }
2519 :
2520 : /* A helper to build the frame DTOR.
2521 : [dcl.fct.def.coroutine] / 12
2522 : The deallocation function’s name is looked up in the scope of the promise
2523 : type. If this lookup fails, the deallocation function’s name is looked up
2524 : in the global scope. If deallocation function lookup finds both a usual
2525 : deallocation function with only a pointer parameter and a usual
2526 : deallocation function with both a pointer parameter and a size parameter,
2527 : then the selected deallocation function shall be the one with two
2528 : parameters. Otherwise, the selected deallocation function shall be the
2529 : function with one parameter. If no usual deallocation function is found
2530 : the program is ill-formed. The selected deallocation function shall be
2531 : called with the address of the block of storage to be reclaimed as its
2532 : first argument. If a deallocation function with a parameter of type
2533 : std::size_t is used, the size of the block is passed as the corresponding
2534 : argument. */
2535 :
2536 : static tree
2537 : build_coroutine_frame_delete_expr (tree, tree, tree, location_t);
2538 :
2539 : /* The actor transform. */
2540 :
2541 : static void
2542 1589 : build_actor_fn (location_t loc, tree coro_frame_type, tree actor, tree fnbody,
2543 : tree orig, hash_map<tree, local_var_info> *local_var_uses,
2544 : hash_map<tree, suspend_point_info> *suspend_points,
2545 : vec<tree> *param_dtor_list,
2546 : tree resume_idx_var, unsigned body_count, tree frame_size,
2547 : bool inline_p)
2548 : {
2549 1589 : verify_stmt_tree (fnbody);
2550 : /* Some things we inherit from the original function. */
2551 1589 : tree promise_type = get_coroutine_promise_type (orig);
2552 1589 : tree promise_proxy = get_coroutine_promise_proxy (orig);
2553 :
2554 : /* One param, the coro frame pointer. */
2555 1589 : tree actor_fp = DECL_ARGUMENTS (actor);
2556 :
2557 1589 : bool spf = start_preparsed_function (actor, NULL_TREE, SF_PRE_PARSED);
2558 1589 : gcc_checking_assert (spf);
2559 1589 : gcc_checking_assert (cfun && current_function_decl && TREE_STATIC (actor));
2560 1589 : if (flag_exceptions)
2561 : /* We, unconditionally, add a try/catch and rethrow.
2562 : TODO: Determine if the combination of initial suspend and the original
2563 : body cannot throw, and elide these additions. */
2564 1567 : cp_function_chain->can_throw = true;
2565 1589 : tree stmt = begin_function_body ();
2566 :
2567 1589 : tree actor_bind = build3 (BIND_EXPR, void_type_node, NULL, NULL, NULL);
2568 1589 : tree top_block = make_node (BLOCK);
2569 1589 : BIND_EXPR_BLOCK (actor_bind) = top_block;
2570 :
2571 1589 : tree continuation = coro_build_artificial_var (loc, coro_actor_continue_id,
2572 : void_coro_handle_type, actor,
2573 : NULL_TREE);
2574 :
2575 1589 : BIND_EXPR_VARS (actor_bind) = continuation;
2576 1589 : BLOCK_VARS (top_block) = BIND_EXPR_VARS (actor_bind) ;
2577 :
2578 : /* Link in the block associated with the outer scope of the re-written
2579 : function body. */
2580 1589 : tree first = expr_first (fnbody);
2581 1589 : gcc_checking_assert (first && TREE_CODE (first) == BIND_EXPR);
2582 1589 : tree block = BIND_EXPR_BLOCK (first);
2583 1589 : gcc_checking_assert (BLOCK_SUPERCONTEXT (block) == NULL_TREE);
2584 1589 : gcc_checking_assert (BLOCK_CHAIN (block) == NULL_TREE);
2585 1589 : BLOCK_SUPERCONTEXT (block) = top_block;
2586 1589 : BLOCK_SUBBLOCKS (top_block) = block;
2587 :
2588 1589 : add_stmt (actor_bind);
2589 1589 : tree actor_body = push_stmt_list ();
2590 :
2591 : /* The entry point for the actor code from the ramp. */
2592 1589 : tree actor_begin_label
2593 1589 : = create_named_label_with_ctx (loc, "actor.begin", actor);
2594 1589 : tree actor_frame = build1_loc (loc, INDIRECT_REF, coro_frame_type, actor_fp);
2595 :
2596 : /* Declare the continuation handle. */
2597 1589 : add_decl_expr (continuation);
2598 :
2599 : /* Re-write local vars, similarly. */
2600 1589 : local_vars_transform xform_vars_data
2601 1589 : = {actor, actor_frame, coro_frame_type, loc, local_var_uses};
2602 1589 : cp_walk_tree (&fnbody, transform_local_var_uses, &xform_vars_data, NULL);
2603 1589 : tree rat = coro_build_frame_access_expr (actor_frame, coro_resume_index_id,
2604 : false, tf_warning_or_error);
2605 1589 : tree ret_label
2606 1589 : = create_named_label_with_ctx (loc, "actor.suspend.ret", actor);
2607 :
2608 1589 : tree continue_label
2609 1589 : = create_named_label_with_ctx (loc, "actor.continue.ret", actor);
2610 :
2611 : /* Build the dispatcher; for each await expression there is an odd entry
2612 : corresponding to the destruction action and an even entry for the resume
2613 : one:
2614 : if (resume index is odd)
2615 : {
2616 : switch (resume index)
2617 : case 1:
2618 : goto cleanup.
2619 : case ... odd suspension point number
2620 : .CO_ACTOR (... odd suspension point number)
2621 : break;
2622 : default:
2623 : break;
2624 : }
2625 : else
2626 : {
2627 : coro.restart.dispatch:
2628 : case 0:
2629 : goto start.
2630 : case ... even suspension point number
2631 : .CO_ACTOR (... even suspension point number)
2632 : break;
2633 : default:
2634 : break;
2635 : }
2636 : we should not get here unless something is broken badly.
2637 : __builtin_trap ();
2638 : */
2639 1589 : tree lsb_if = begin_if_stmt ();
2640 1589 : tree chkb0 = build2 (BIT_AND_EXPR, short_unsigned_type_node, rat,
2641 : build_int_cst (short_unsigned_type_node, 1));
2642 1589 : chkb0 = build2 (NE_EXPR, short_unsigned_type_node, chkb0,
2643 : build_int_cst (short_unsigned_type_node, 0));
2644 1589 : finish_if_stmt_cond (chkb0, lsb_if);
2645 :
2646 1589 : tree destroy_dispatcher = begin_switch_stmt ();
2647 1589 : finish_switch_cond (rat, destroy_dispatcher);
2648 :
2649 : /* The destroy point numbered #1 is special, in that it is reached from a
2650 : coroutine that is suspended after re-throwing from unhandled_exception().
2651 : This label just invokes the cleanup of promise, param copies and the
2652 : frame itself. */
2653 1589 : tree del_promise_label
2654 1589 : = create_named_label_with_ctx (loc, "coro.delete.promise", actor);
2655 1589 : finish_case_label (loc, build_int_cst (short_unsigned_type_node, 1),
2656 : NULL_TREE);
2657 1589 : add_stmt (build_stmt (loc, GOTO_EXPR, del_promise_label));
2658 :
2659 1589 : short unsigned lab_num = 3;
2660 5792 : for (unsigned destr_pt = 0; destr_pt < body_count; destr_pt++)
2661 : {
2662 4203 : tree l_num = build_int_cst (short_unsigned_type_node, lab_num);
2663 4203 : finish_case_label (loc, l_num, NULL_TREE);
2664 4203 : tree c = build_call_expr_internal_loc (loc, IFN_CO_ACTOR, void_type_node,
2665 : 1, l_num);
2666 4203 : finish_expr_stmt (c);
2667 4203 : finish_break_stmt ();
2668 4203 : lab_num += 2;
2669 : }
2670 1589 : finish_case_label (loc, NULL_TREE, NULL_TREE);
2671 1589 : finish_break_stmt ();
2672 :
2673 : /* Finish the destroy dispatcher. */
2674 1589 : finish_switch_stmt (destroy_dispatcher);
2675 :
2676 1589 : finish_then_clause (lsb_if);
2677 1589 : begin_else_clause (lsb_if);
2678 :
2679 : /* For the case of a boolean await_resume () that returns 'true' we should
2680 : restart the dispatch, since we cannot know if additional resumes were
2681 : executed from within the await_suspend function. */
2682 1589 : tree restart_dispatch_label
2683 1589 : = create_named_label_with_ctx (loc, "coro.restart.dispatch", actor);
2684 1589 : add_stmt (build_stmt (loc, LABEL_EXPR, restart_dispatch_label));
2685 :
2686 1589 : tree dispatcher = begin_switch_stmt ();
2687 1589 : finish_switch_cond (rat, dispatcher);
2688 1589 : finish_case_label (loc, build_int_cst (short_unsigned_type_node, 0),
2689 : NULL_TREE);
2690 1589 : add_stmt (build_stmt (loc, GOTO_EXPR, actor_begin_label));
2691 :
2692 1589 : lab_num = 2;
2693 : /* The final resume should be made to hit the default (trap, UB) entry
2694 : although it will be unreachable via the normal entry point, since that
2695 : is set to NULL on reaching final suspend. */
2696 5792 : for (unsigned resu_pt = 0; resu_pt < body_count; resu_pt++)
2697 : {
2698 4203 : tree l_num = build_int_cst (short_unsigned_type_node, lab_num);
2699 4203 : finish_case_label (loc, l_num, NULL_TREE);
2700 4203 : tree c = build_call_expr_internal_loc (loc, IFN_CO_ACTOR, void_type_node,
2701 : 1, l_num);
2702 4203 : finish_expr_stmt (c);
2703 4203 : finish_break_stmt ();
2704 4203 : lab_num += 2;
2705 : }
2706 1589 : finish_case_label (loc, NULL_TREE, NULL_TREE);
2707 1589 : finish_break_stmt ();
2708 :
2709 : /* Finish the resume dispatcher. */
2710 1589 : finish_switch_stmt (dispatcher);
2711 :
2712 1589 : finish_else_clause (lsb_if);
2713 1589 : finish_if_stmt (lsb_if);
2714 :
2715 : /* If we reach here then we've hit UB. */
2716 1589 : tree t = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_TRAP), 0);
2717 1589 : finish_expr_stmt (t);
2718 :
2719 : /* Now we start building the rewritten function body. */
2720 1589 : add_stmt (build_stmt (loc, LABEL_EXPR, actor_begin_label));
2721 :
2722 1589 : tree i_a_r_c = NULL_TREE;
2723 1589 : if (flag_exceptions)
2724 : {
2725 1567 : i_a_r_c
2726 1567 : = coro_build_frame_access_expr (actor_frame, coro_frame_i_a_r_c_id,
2727 : false, tf_warning_or_error);
2728 1567 : tree m = cp_build_modify_expr (loc, i_a_r_c, NOP_EXPR,
2729 : boolean_false_node, tf_warning_or_error);
2730 1567 : finish_expr_stmt (m);
2731 : }
2732 :
2733 : /* Now we know the real promise, and enough about the frame layout to
2734 : decide where to put things. */
2735 :
2736 1589 : await_xform_data xform = {actor, actor_frame, suspend_points};
2737 :
2738 : /* Transform the await expressions in the function body. Only do each
2739 : await tree once! */
2740 1589 : hash_set<tree> pset;
2741 1589 : cp_walk_tree (&fnbody, transform_await_wrapper, &xform, &pset);
2742 :
2743 : /* Add in our function body with the co_returns rewritten to final form. */
2744 1589 : add_stmt (fnbody);
2745 :
2746 : /* We are done with the frame, but if the ramp still has a hold on it
2747 : we should not cleanup. So decrement the refcount and then return to
2748 : the ramp if it is > 0. */
2749 1589 : tree coro_frame_refcount
2750 1589 : = coro_build_frame_access_expr (actor_frame, coro_frame_refcount_id,
2751 : false, tf_warning_or_error);
2752 1589 : tree released = build2_loc (loc, MINUS_EXPR, short_unsigned_type_node,
2753 : coro_frame_refcount,
2754 : build_int_cst (short_unsigned_type_node, 1));
2755 1589 : tree r = cp_build_modify_expr (loc, coro_frame_refcount, NOP_EXPR, released,
2756 : tf_warning_or_error);
2757 1589 : finish_expr_stmt (r);
2758 1589 : tree cond = build2_loc (loc, NE_EXPR, short_unsigned_type_node,
2759 : coro_frame_refcount,
2760 : build_int_cst (short_unsigned_type_node, 0));
2761 1589 : tree ramp_cu_if = begin_if_stmt ();
2762 1589 : finish_if_stmt_cond (cond, ramp_cu_if);
2763 1589 : finish_return_stmt (NULL_TREE);
2764 1589 : finish_then_clause (ramp_cu_if);
2765 1589 : finish_if_stmt (ramp_cu_if);
2766 :
2767 : /* Otherwise, do the tail of the function; first cleanups. */
2768 1589 : r = build_stmt (loc, LABEL_EXPR, del_promise_label);
2769 1589 : add_stmt (r);
2770 :
2771 : /* Destructors for the things we built explicitly.
2772 : promise... */
2773 1589 : if (tree c = cxx_maybe_build_cleanup (promise_proxy, tf_warning_or_error))
2774 951 : finish_expr_stmt (c);
2775 :
2776 : /* Argument copies ... */
2777 1704 : while (!param_dtor_list->is_empty ())
2778 : {
2779 115 : tree parm_id = param_dtor_list->pop ();
2780 115 : tree a = coro_build_frame_access_expr (actor_frame, parm_id, false,
2781 : tf_warning_or_error);
2782 115 : if (tree dtor = cxx_maybe_build_cleanup (a, tf_warning_or_error))
2783 115 : finish_expr_stmt (dtor);
2784 : }
2785 :
2786 : /* Here deallocate the frame (if we allocated it), which we will have at
2787 : present. */
2788 1589 : tree fnf2_x
2789 1589 : = coro_build_frame_access_expr (actor_frame, coro_frame_needs_free_id,
2790 : false, tf_warning_or_error);
2791 1589 : tree need_free_if = begin_if_stmt ();
2792 1589 : finish_if_stmt_cond (fnf2_x, need_free_if);
2793 :
2794 : /* Build the frame DTOR. */
2795 1589 : tree del_coro_fr
2796 1589 : = build_coroutine_frame_delete_expr (actor_fp, frame_size,
2797 : promise_type, loc);
2798 1589 : finish_expr_stmt (del_coro_fr);
2799 1589 : finish_then_clause (need_free_if);
2800 1589 : finish_if_stmt (need_free_if);
2801 :
2802 : /* Done. */
2803 1589 : finish_return_stmt (NULL_TREE);
2804 :
2805 : /* This is the suspend return point. */
2806 1589 : add_stmt (build_stmt (loc, LABEL_EXPR, ret_label));
2807 :
2808 1589 : finish_return_stmt (NULL_TREE);
2809 :
2810 : /* This is the 'continuation' return point. For such a case we have a coro
2811 : handle (from the await_suspend() call) and we want handle.resume() to
2812 : execute as a tailcall allowing arbitrary chaining of coroutines. */
2813 1589 : add_stmt (build_stmt (loc, LABEL_EXPR, continue_label));
2814 :
2815 : /* Should have been set earlier by the coro_initialized code. */
2816 1589 : gcc_assert (void_coro_handle_address);
2817 :
2818 : /* We want to force a tail-call even for O0/1, so this expands the resume
2819 : call into its underlying implementation. */
2820 1589 : tree addr = build_new_method_call (continuation, void_coro_handle_address,
2821 : NULL, NULL_TREE, LOOKUP_NORMAL, NULL,
2822 : tf_warning_or_error);
2823 1589 : tree resume = build_call_expr_loc
2824 1589 : (loc, builtin_decl_explicit (BUILT_IN_CORO_RESUME), 1, addr);
2825 :
2826 : /* In order to support an arbitrary number of coroutine continuations,
2827 : we must tail call them. However, some targets do not support indirect
2828 : tail calls to arbitrary callees. See PR94359. */
2829 1589 : CALL_EXPR_TAILCALL (resume) = true;
2830 1589 : finish_expr_stmt (resume);
2831 :
2832 1589 : r = build_stmt (loc, RETURN_EXPR, NULL);
2833 1589 : gcc_checking_assert (maybe_cleanup_point_expr_void (r) == r);
2834 1589 : add_stmt (r);
2835 :
2836 : /* How to construct the handle for this coroutine from the frame address. */
2837 1589 : tree hfa_m = get_coroutine_from_address (orig);
2838 : /* Should have been set earlier by coro_promise_type_found_p. */
2839 1589 : gcc_assert (hfa_m);
2840 3178 : tree handle_type = TREE_TYPE (get_coroutine_self_handle_proxy (orig));
2841 :
2842 : /* We've now rewritten the tree and added the initial and final
2843 : co_awaits. Now pass over the tree and expand the co_awaits. */
2844 :
2845 1589 : coro_aw_data data = {actor, actor_fp, resume_idx_var, i_a_r_c,
2846 : del_promise_label, ret_label,
2847 : continue_label, restart_dispatch_label, continuation,
2848 1589 : handle_type, hfa_m, 2};
2849 1589 : cp_walk_tree (&actor_body, await_statement_expander, &data, NULL);
2850 :
2851 1589 : BIND_EXPR_BODY (actor_bind) = pop_stmt_list (actor_body);
2852 1589 : TREE_SIDE_EFFECTS (actor_bind) = true;
2853 :
2854 1589 : cfun->coroutine_component = 1;
2855 1589 : finish_function_body (stmt);
2856 1589 : finish_function (inline_p);
2857 1589 : }
2858 :
2859 : /* The prototype 'destroy' function :
2860 : frame->__Coro_resume_index |= 1;
2861 : actor (frame); */
2862 :
2863 : static void
2864 1589 : build_destroy_fn (location_t loc, tree coro_frame_type, tree destroy,
2865 : tree actor, bool inline_p)
2866 : {
2867 : /* One param, the coro frame pointer. */
2868 1589 : tree destr_fp = DECL_ARGUMENTS (destroy);
2869 1589 : gcc_checking_assert (POINTER_TYPE_P (TREE_TYPE (destr_fp))
2870 : && same_type_p (coro_frame_type,
2871 : TREE_TYPE (TREE_TYPE (destr_fp))));
2872 :
2873 1589 : bool spf = start_preparsed_function (destroy, NULL_TREE, SF_PRE_PARSED);
2874 1589 : gcc_checking_assert (spf);
2875 1589 : tree dstr_stmt = begin_function_body ();
2876 :
2877 1589 : tree destr_frame
2878 1589 : = cp_build_indirect_ref (loc, destr_fp, RO_UNARY_STAR,
2879 : tf_warning_or_error);
2880 :
2881 1589 : tree rat = coro_build_frame_access_expr (destr_frame, coro_resume_index_id,
2882 : false, tf_warning_or_error);
2883 :
2884 : /* _resume_at |= 1 */
2885 1589 : tree dstr_idx
2886 1589 : = build2_loc (loc, BIT_IOR_EXPR, short_unsigned_type_node, rat,
2887 : build_int_cst (short_unsigned_type_node, 1));
2888 1589 : tree r = cp_build_modify_expr (loc, rat, NOP_EXPR, dstr_idx,
2889 : tf_warning_or_error);
2890 1589 : finish_expr_stmt (r);
2891 :
2892 : /* So .. call the actor .. */
2893 1589 : finish_expr_stmt (build_call_expr_loc (loc, actor, 1, destr_fp));
2894 :
2895 : /* done. */
2896 1589 : finish_return_stmt (NULL_TREE);
2897 :
2898 1589 : gcc_checking_assert (cfun && current_function_decl);
2899 1589 : cfun->coroutine_component = 1;
2900 1589 : finish_function_body (dstr_stmt);
2901 1589 : finish_function (inline_p);
2902 1589 : }
2903 :
2904 : /* Helper that returns an identifier for an appended extension to the
2905 : current un-mangled function name. */
2906 :
2907 : static tree
2908 1673 : get_fn_local_identifier (tree orig, const char *append)
2909 : {
2910 : /* Figure out the bits we need to generate names for the outlined things
2911 : For consistency, this needs to behave the same way as
2912 : ASM_FORMAT_PRIVATE_NAME does. */
2913 1673 : tree nm = DECL_NAME (orig);
2914 1673 : const char *sep, *pfx = "";
2915 : #ifndef NO_DOT_IN_LABEL
2916 1673 : sep = ".";
2917 : #else
2918 : #ifndef NO_DOLLAR_IN_LABEL
2919 : sep = "$";
2920 : #else
2921 : sep = "_";
2922 : pfx = "__";
2923 : #endif
2924 : #endif
2925 :
2926 1673 : char *an;
2927 1673 : if (DECL_ASSEMBLER_NAME (orig))
2928 1673 : an = ACONCAT ((IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (orig)), sep, append,
2929 : (char *) 0));
2930 0 : else if (DECL_USE_TEMPLATE (orig) && DECL_TEMPLATE_INFO (orig)
2931 0 : && DECL_TI_ARGS (orig))
2932 : {
2933 0 : tree tpl_args = DECL_TI_ARGS (orig);
2934 0 : an = ACONCAT ((pfx, IDENTIFIER_POINTER (nm), (char *) 0));
2935 0 : for (int i = 0; i < TREE_VEC_LENGTH (tpl_args); ++i)
2936 : {
2937 0 : tree typ = DECL_NAME (TYPE_NAME (TREE_VEC_ELT (tpl_args, i)));
2938 0 : an = ACONCAT ((an, sep, IDENTIFIER_POINTER (typ), (char *) 0));
2939 : }
2940 0 : an = ACONCAT ((an, sep, append, (char *) 0));
2941 : }
2942 : else
2943 0 : an = ACONCAT ((pfx, IDENTIFIER_POINTER (nm), sep, append, (char *) 0));
2944 :
2945 1673 : return get_identifier (an);
2946 : }
2947 :
2948 : /* Build an initial or final await initialized from the promise
2949 : initial_suspend or final_suspend expression. */
2950 :
2951 : static tree
2952 3154 : build_init_or_final_await (location_t loc, bool is_final)
2953 : {
2954 3154 : tree suspend_alt = is_final ? coro_final_suspend_identifier
2955 : : coro_initial_suspend_identifier;
2956 :
2957 3154 : tree setup_call
2958 3154 : = coro_build_promise_expression (current_function_decl, NULL, suspend_alt,
2959 : loc, NULL, /*musthave=*/true);
2960 :
2961 : /* Check for noexcept on the final_suspend call. */
2962 3110 : if (flag_exceptions && is_final && setup_call != error_mark_node
2963 4703 : && coro_diagnose_throwing_final_aw_expr (setup_call))
2964 3 : return error_mark_node;
2965 :
2966 : /* So build the co_await for this */
2967 : /* For initial/final suspends the call is "a" per [expr.await] 3.2. */
2968 4731 : return build_co_await (loc, setup_call, (is_final ? FINAL_SUSPEND_POINT
2969 3151 : : INITIAL_SUSPEND_POINT));
2970 : }
2971 :
2972 : /* Callback to record the essential data for each await point found in the
2973 : function. */
2974 :
2975 : static bool
2976 4245 : register_await_info (tree await_expr, tree aw_type, tree aw_nam,
2977 : hash_map<tree, suspend_point_info> *suspend_points)
2978 : {
2979 4245 : bool seen;
2980 4245 : suspend_point_info &s
2981 4245 : = suspend_points->get_or_insert (await_expr, &seen);
2982 4245 : if (seen)
2983 : {
2984 0 : warning_at (EXPR_LOCATION (await_expr), 0, "duplicate info for %qE",
2985 : await_expr);
2986 0 : return false;
2987 : }
2988 4245 : s.awaitable_type = aw_type;
2989 4245 : s.await_field_id = aw_nam;
2990 4245 : return true;
2991 : }
2992 :
2993 : /* If this is an await expression, then count it (both uniquely within the
2994 : function and locally within a single statement). */
2995 :
2996 : static tree
2997 208832 : register_awaits (tree *stmt, int *, void *d)
2998 : {
2999 208832 : tree aw_expr = *stmt;
3000 :
3001 : /* We should have already lowered co_yields to their co_await. */
3002 208832 : gcc_checking_assert (TREE_CODE (aw_expr) != CO_YIELD_EXPR);
3003 :
3004 208832 : if (TREE_CODE (aw_expr) != CO_AWAIT_EXPR)
3005 : return NULL_TREE;
3006 :
3007 : /* Count how many awaits the current expression contains. */
3008 4245 : susp_frame_data *data = (susp_frame_data *) d;
3009 4245 : data->saw_awaits++;
3010 : /* Each await suspend context is unique, this is a function-wide value. */
3011 4245 : data->await_number++;
3012 :
3013 : /* Awaitables should either be user-locals or promoted to coroutine frame
3014 : entries at this point, and their initializers should have been broken
3015 : out. */
3016 4245 : tree aw = TREE_OPERAND (aw_expr, 1);
3017 4245 : gcc_checking_assert (!TREE_OPERAND (aw_expr, 2));
3018 :
3019 4245 : tree aw_field_type = TREE_TYPE (aw);
3020 4245 : tree aw_field_nam = NULL_TREE;
3021 4245 : register_await_info (aw_expr, aw_field_type, aw_field_nam, data->suspend_points);
3022 :
3023 : /* Rewrite target expressions on the await_suspend () to remove extraneous
3024 : cleanups for the awaitables, which are now promoted to frame vars and
3025 : managed via that. */
3026 4245 : tree v = TREE_OPERAND (aw_expr, 3);
3027 4245 : tree o = TREE_VEC_ELT (v, 1);
3028 4245 : if (TREE_CODE (o) == TARGET_EXPR)
3029 114 : TREE_VEC_ELT (v, 1) = get_target_expr (TARGET_EXPR_INITIAL (o));
3030 : return NULL_TREE;
3031 : }
3032 :
3033 : /* There are cases where any await expression is relevant. */
3034 : static tree
3035 536209 : find_any_await (tree *stmt, int *dosub, void *d)
3036 : {
3037 536209 : if (TREE_CODE (*stmt) == CO_AWAIT_EXPR)
3038 : {
3039 4351 : *dosub = 0; /* We don't need to consider this any further. */
3040 4351 : if (d)
3041 4342 : *(tree **)d = stmt;
3042 4351 : return *stmt;
3043 : }
3044 : return NULL_TREE;
3045 : }
3046 :
3047 : static bool
3048 70387 : tmp_target_expr_p (tree t)
3049 : {
3050 70387 : if (TREE_CODE (t) != TARGET_EXPR)
3051 : return false;
3052 5180 : tree v = TARGET_EXPR_SLOT (t);
3053 5180 : if (!DECL_ARTIFICIAL (v))
3054 : return false;
3055 5180 : if (DECL_NAME (v))
3056 182 : return false;
3057 : return true;
3058 : }
3059 :
3060 : /* Structure to record sub-expressions that need to be handled by the
3061 : statement flattener. */
3062 :
3063 : struct coro_interesting_subtree
3064 : {
3065 : tree* entry;
3066 : hash_set<tree> *temps_used;
3067 : };
3068 :
3069 : /* tree-walk callback that returns the first encountered sub-expression of
3070 : a kind that needs to be handled specifically by the statement flattener. */
3071 :
3072 : static tree
3073 78838 : find_interesting_subtree (tree *expr_p, int *dosub, void *d)
3074 : {
3075 78838 : tree expr = *expr_p;
3076 78838 : coro_interesting_subtree *p = (coro_interesting_subtree *)d;
3077 78838 : if (TREE_CODE (expr) == CO_AWAIT_EXPR)
3078 : {
3079 8451 : *dosub = 0; /* We don't need to consider this any further. */
3080 8451 : if (TREE_OPERAND (expr, 2))
3081 : {
3082 4192 : p->entry = expr_p;
3083 4192 : return expr;
3084 : }
3085 : }
3086 70387 : else if (tmp_target_expr_p (expr)
3087 4998 : && !TARGET_EXPR_ELIDING_P (expr)
3088 70731 : && !p->temps_used->contains (expr))
3089 : {
3090 327 : p->entry = expr_p;
3091 327 : return expr;
3092 : }
3093 :
3094 : return NULL_TREE;
3095 : }
3096 :
3097 : /* Node for a doubly-linked list of promoted variables and their
3098 : initializers. When the initializer is a conditional expression
3099 : the 'then' and 'else' clauses are represented by a linked list
3100 : attached to then_cl and else_cl respectively. */
3101 :
3102 : struct var_nest_node
3103 : {
3104 : var_nest_node () = default;
3105 8759 : var_nest_node (tree v, tree i, var_nest_node *p, var_nest_node *n)
3106 8759 : : var(v), init(i), prev(p), next(n), then_cl (NULL), else_cl (NULL)
3107 : {
3108 8759 : if (p)
3109 26 : p->next = this;
3110 26 : if (n)
3111 4552 : n->prev = this;
3112 : }
3113 : tree var;
3114 : tree init;
3115 : var_nest_node *prev;
3116 : var_nest_node *next;
3117 : var_nest_node *then_cl;
3118 : var_nest_node *else_cl;
3119 : };
3120 :
3121 : /* This is called for single statements from the co-await statement walker.
3122 : It checks to see if the statement contains any initializers for awaitables
3123 : and if any of these capture items by reference. */
3124 :
3125 : static void
3126 13278 : flatten_await_stmt (var_nest_node *n, hash_set<tree> *promoted,
3127 : hash_set<tree> *temps_used, tree *replace_in)
3128 : {
3129 13393 : bool init_expr = false;
3130 13393 : switch (TREE_CODE (n->init))
3131 : {
3132 : default: break;
3133 : /* Compound expressions must be flattened specifically. */
3134 15 : case COMPOUND_EXPR:
3135 15 : {
3136 15 : tree first = TREE_OPERAND (n->init, 0);
3137 15 : n->init = TREE_OPERAND (n->init, 1);
3138 15 : var_nest_node *ins
3139 15 : = new var_nest_node(NULL_TREE, first, n->prev, n);
3140 : /* The compiler (but not the user) can generate temporaries with
3141 : uses in the second arm of a compound expr. */
3142 15 : flatten_await_stmt (ins, promoted, temps_used, &n->init);
3143 15 : flatten_await_stmt (n, promoted, temps_used, NULL);
3144 : /* The two arms have been processed separately. */
3145 13293 : return;
3146 : }
3147 5313 : break;
3148 : /* Handle conditional expressions. */
3149 5313 : case INIT_EXPR:
3150 5313 : init_expr = true;
3151 : /* FALLTHROUGH */
3152 5682 : case MODIFY_EXPR:
3153 5682 : {
3154 5682 : tree old_expr = TREE_OPERAND (n->init, 1);
3155 5682 : if (TREE_CODE (old_expr) == COMPOUND_EXPR)
3156 : {
3157 100 : tree first = TREE_OPERAND (old_expr, 0);
3158 100 : TREE_OPERAND (n->init, 1) = TREE_OPERAND (old_expr, 1);
3159 100 : var_nest_node *ins
3160 100 : = new var_nest_node(NULL_TREE, first, n->prev, n);
3161 100 : flatten_await_stmt (ins, promoted, temps_used,
3162 : &TREE_OPERAND (n->init, 1));
3163 100 : flatten_await_stmt (n, promoted, temps_used, NULL);
3164 100 : return;
3165 : }
3166 5582 : if (TREE_CODE (old_expr) != COND_EXPR)
3167 : break;
3168 : /* Reconstruct x = t ? y : z;
3169 : as (void) t ? x = y : x = z; */
3170 14 : tree var = TREE_OPERAND (n->init, 0);
3171 14 : tree var_type = TREE_TYPE (var);
3172 14 : tree cond = COND_EXPR_COND (old_expr);
3173 : /* We are allowed a void type throw in one or both of the cond
3174 : expr arms. */
3175 14 : tree then_cl = COND_EXPR_THEN (old_expr);
3176 14 : if (!VOID_TYPE_P (TREE_TYPE (then_cl)))
3177 : {
3178 14 : gcc_checking_assert (TREE_CODE (then_cl) != STATEMENT_LIST);
3179 14 : if (init_expr)
3180 14 : then_cl = cp_build_init_expr (var, then_cl);
3181 : else
3182 0 : then_cl = build2 (MODIFY_EXPR, var_type, var, then_cl);
3183 : }
3184 14 : tree else_cl = COND_EXPR_ELSE (old_expr);
3185 14 : if (!VOID_TYPE_P (TREE_TYPE (else_cl)))
3186 : {
3187 14 : gcc_checking_assert (TREE_CODE (else_cl) != STATEMENT_LIST);
3188 14 : if (init_expr)
3189 14 : else_cl = cp_build_init_expr (var, else_cl);
3190 : else
3191 0 : else_cl = build2 (MODIFY_EXPR, var_type, var, else_cl);
3192 : }
3193 14 : n->init = build3 (COND_EXPR, var_type, cond, then_cl, else_cl);
3194 : }
3195 : /* FALLTHROUGH */
3196 17 : case COND_EXPR:
3197 17 : {
3198 17 : tree *found;
3199 17 : tree cond = COND_EXPR_COND (n->init);
3200 : /* If the condition contains an await expression, then we need to
3201 : set that first and use a separate var. */
3202 17 : if (cp_walk_tree (&cond, find_any_await, &found, NULL))
3203 : {
3204 17 : tree cond_type = TREE_TYPE (cond);
3205 17 : tree cond_var = build_lang_decl (VAR_DECL, NULL_TREE, cond_type);
3206 17 : DECL_ARTIFICIAL (cond_var) = true;
3207 17 : layout_decl (cond_var, 0);
3208 17 : gcc_checking_assert (!TYPE_NEEDS_CONSTRUCTING (cond_type));
3209 17 : cond = cp_build_init_expr (cond_var, cond);
3210 17 : var_nest_node *ins
3211 17 : = new var_nest_node (cond_var, cond, n->prev, n);
3212 17 : COND_EXPR_COND (n->init) = cond_var;
3213 17 : flatten_await_stmt (ins, promoted, temps_used, NULL);
3214 : }
3215 :
3216 17 : n->then_cl
3217 17 : = new var_nest_node (n->var, COND_EXPR_THEN (n->init), NULL, NULL);
3218 17 : n->else_cl
3219 17 : = new var_nest_node (n->var, COND_EXPR_ELSE (n->init), NULL, NULL);
3220 17 : flatten_await_stmt (n->then_cl, promoted, temps_used, NULL);
3221 : /* Point to the start of the flattened code. */
3222 51 : while (n->then_cl->prev)
3223 17 : n->then_cl = n->then_cl->prev;
3224 17 : flatten_await_stmt (n->else_cl, promoted, temps_used, NULL);
3225 34 : while (n->else_cl->prev)
3226 0 : n->else_cl = n->else_cl->prev;
3227 17 : return;
3228 : }
3229 13261 : break;
3230 : }
3231 13261 : coro_interesting_subtree v = { NULL, temps_used };
3232 13261 : tree t = cp_walk_tree (&n->init, find_interesting_subtree, (void *)&v, NULL);
3233 13261 : if (!t)
3234 : return;
3235 4519 : switch (TREE_CODE (t))
3236 : {
3237 0 : default: break;
3238 4192 : case CO_AWAIT_EXPR:
3239 4192 : {
3240 : /* Await expressions with initializers have a compiler-temporary
3241 : as the awaitable. 'promote' this. */
3242 4192 : tree var = TREE_OPERAND (t, 1);
3243 4192 : bool already_present = promoted->add (var);
3244 4192 : gcc_checking_assert (!already_present);
3245 4192 : tree init = TREE_OPERAND (t, 2);
3246 4192 : switch (TREE_CODE (init))
3247 : {
3248 : default: break;
3249 4192 : case INIT_EXPR:
3250 4192 : case MODIFY_EXPR:
3251 4192 : {
3252 4192 : tree inner = TREE_OPERAND (init, 1);
3253 : /* We can have non-lvalue-expressions here, but when we see
3254 : a target expression, mark it as already used. */
3255 4192 : if (TREE_CODE (inner) == TARGET_EXPR)
3256 : {
3257 4145 : temps_used->add (inner);
3258 4145 : gcc_checking_assert
3259 : (TREE_CODE (TARGET_EXPR_INITIAL (inner)) != COND_EXPR);
3260 : }
3261 : }
3262 4192 : break;
3263 0 : case CALL_EXPR:
3264 : /* If this is a call and not a CTOR, then we didn't expect it. */
3265 0 : gcc_checking_assert
3266 : (DECL_CONSTRUCTOR_P (TREE_OPERAND (CALL_EXPR_FN (init), 0)));
3267 : break;
3268 : }
3269 4192 : var_nest_node *ins = new var_nest_node (var, init, n->prev, n);
3270 4192 : TREE_OPERAND (t, 2) = NULL_TREE;
3271 4192 : flatten_await_stmt (ins, promoted, temps_used, NULL);
3272 4192 : flatten_await_stmt (n, promoted, temps_used, NULL);
3273 4192 : return;
3274 : }
3275 327 : break;
3276 327 : case TARGET_EXPR:
3277 327 : {
3278 : /* We have a temporary; promote it, but allow for the idiom in code
3279 : generated by the compiler like
3280 : a = (target_expr produces temp, op uses temp). */
3281 327 : tree init = t;
3282 327 : temps_used->add (init);
3283 327 : tree var_type = TREE_TYPE (init);
3284 327 : char *buf = xasprintf ("T%03u", (unsigned) temps_used->elements ());
3285 327 : tree var = build_lang_decl (VAR_DECL, get_identifier (buf), var_type);
3286 327 : DECL_ARTIFICIAL (var) = true;
3287 327 : free (buf);
3288 327 : bool already_present = promoted->add (var);
3289 327 : gcc_checking_assert (!already_present);
3290 327 : tree inner = TARGET_EXPR_INITIAL (init);
3291 327 : gcc_checking_assert
3292 : (TREE_CODE (inner) != COND_EXPR
3293 : || !cp_walk_tree (&inner, find_any_await, nullptr, nullptr));
3294 327 : init = cp_build_modify_expr (input_location, var, INIT_EXPR, init,
3295 : tf_warning_or_error);
3296 : /* Simplify for the case that we have an init containing the temp
3297 : alone. */
3298 327 : if (t == n->init && n->var == NULL_TREE)
3299 : {
3300 99 : n->var = var;
3301 99 : proxy_replace pr = {TARGET_EXPR_SLOT (t), var};
3302 99 : cp_walk_tree (&init, replace_proxy, &pr, NULL);
3303 99 : n->init = init;
3304 99 : if (replace_in)
3305 91 : cp_walk_tree (replace_in, replace_proxy, &pr, NULL);
3306 99 : flatten_await_stmt (n, promoted, temps_used, NULL);
3307 99 : }
3308 : else
3309 : {
3310 228 : var_nest_node *ins
3311 228 : = new var_nest_node (var, init, n->prev, n);
3312 : /* We have to replace the target expr... */
3313 228 : *v.entry = var;
3314 : /* ... and any uses of its var. */
3315 228 : proxy_replace pr = {TARGET_EXPR_SLOT (t), var};
3316 228 : cp_walk_tree (&n->init, replace_proxy, &pr, NULL);
3317 : /* Compiler-generated temporaries can also have uses in
3318 : following arms of compound expressions, which will be listed
3319 : in 'replace_in' if present. */
3320 228 : if (replace_in)
3321 3 : cp_walk_tree (replace_in, replace_proxy, &pr, NULL);
3322 228 : flatten_await_stmt (ins, promoted, temps_used, NULL);
3323 228 : flatten_await_stmt (n, promoted, temps_used, NULL);
3324 : }
3325 327 : return;
3326 : }
3327 0 : break;
3328 : }
3329 : }
3330 :
3331 : /* Helper for 'process_conditional' that handles recursion into nested
3332 : conditionals. */
3333 :
3334 : static void
3335 34 : handle_nested_conditionals (var_nest_node *n, vec<tree>& list,
3336 : hash_map<tree, tree>& map)
3337 : {
3338 51 : do
3339 : {
3340 51 : if (n->var && DECL_NAME (n->var))
3341 : {
3342 17 : list.safe_push (n->var);
3343 17 : if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (n->var)))
3344 : {
3345 0 : bool existed;
3346 0 : tree& flag = map.get_or_insert (n->var, &existed);
3347 0 : if (!existed)
3348 : {
3349 : /* We didn't see this var before and it needs a DTOR, so
3350 : build a guard variable for it. */
3351 0 : char *nam
3352 0 : = xasprintf ("%s_guard",
3353 0 : IDENTIFIER_POINTER (DECL_NAME (n->var)));
3354 0 : flag = build_lang_decl (VAR_DECL, get_identifier (nam),
3355 : boolean_type_node);
3356 0 : free (nam);
3357 0 : DECL_ARTIFICIAL (flag) = true;
3358 : }
3359 :
3360 : /* The initializer for this variable is replaced by a compound
3361 : expression that performs the init and then records that the
3362 : variable is live (and the DTOR should be run at the scope
3363 : exit. */
3364 0 : tree set_flag = cp_build_init_expr (flag, boolean_true_node);
3365 0 : n->init
3366 0 : = build2 (COMPOUND_EXPR, boolean_type_node, n->init, set_flag);
3367 : }
3368 : }
3369 51 : if (TREE_CODE (n->init) == COND_EXPR)
3370 : {
3371 0 : tree new_then = push_stmt_list ();
3372 0 : handle_nested_conditionals (n->then_cl, list, map);
3373 0 : new_then = pop_stmt_list (new_then);
3374 0 : tree new_else = push_stmt_list ();
3375 0 : handle_nested_conditionals (n->else_cl, list, map);
3376 0 : new_else = pop_stmt_list (new_else);
3377 0 : tree new_if
3378 0 : = build4 (IF_STMT, void_type_node, COND_EXPR_COND (n->init),
3379 : new_then, new_else, NULL_TREE);
3380 0 : add_stmt (new_if);
3381 : }
3382 : else
3383 51 : finish_expr_stmt (n->init);
3384 51 : n = n->next;
3385 51 : } while (n);
3386 34 : }
3387 :
3388 : /* helper for 'maybe_promote_temps'.
3389 :
3390 : When we have a conditional expression which might embed await expressions
3391 : and/or promoted variables, we need to handle it appropriately.
3392 :
3393 : The linked lists for the 'then' and 'else' clauses in a conditional node
3394 : identify the promoted variables (but these cannot be wrapped in a regular
3395 : cleanup).
3396 :
3397 : So recurse through the lists and build up a composite list of captured vars.
3398 : Declare these and any guard variables needed to decide if a DTOR should be
3399 : run. Then embed the conditional into a try-finally expression that handles
3400 : running each DTOR conditionally on its guard variable. */
3401 :
3402 : static void
3403 17 : process_conditional (var_nest_node *n, tree& vlist)
3404 : {
3405 17 : tree init = n->init;
3406 17 : hash_map<tree, tree> var_flags;
3407 17 : auto_vec<tree> var_list;
3408 17 : tree new_then = push_stmt_list ();
3409 17 : handle_nested_conditionals (n->then_cl, var_list, var_flags);
3410 17 : new_then = pop_stmt_list (new_then);
3411 17 : tree new_else = push_stmt_list ();
3412 17 : handle_nested_conditionals (n->else_cl, var_list, var_flags);
3413 17 : new_else = pop_stmt_list (new_else);
3414 : /* Declare the vars. There are two loops so that the boolean flags are
3415 : grouped in the frame. */
3416 68 : for (unsigned i = 0; i < var_list.length(); i++)
3417 : {
3418 17 : tree var = var_list[i];
3419 17 : DECL_CHAIN (var) = vlist;
3420 17 : vlist = var;
3421 17 : add_decl_expr (var);
3422 : }
3423 : /* Define the guard flags for variables that need a DTOR. */
3424 34 : for (unsigned i = 0; i < var_list.length(); i++)
3425 : {
3426 17 : tree *flag = var_flags.get (var_list[i]);
3427 17 : if (flag)
3428 : {
3429 0 : DECL_INITIAL (*flag) = boolean_false_node;
3430 0 : DECL_CHAIN (*flag) = vlist;
3431 0 : vlist = *flag;
3432 0 : add_decl_expr (*flag);
3433 : }
3434 : }
3435 17 : tree new_if
3436 17 : = build4 (IF_STMT, void_type_node, COND_EXPR_COND (init),
3437 : new_then, new_else, NULL_TREE);
3438 : /* Build a set of conditional DTORs. */
3439 17 : tree final_actions = push_stmt_list ();
3440 51 : while (!var_list.is_empty())
3441 : {
3442 17 : tree var = var_list.pop ();
3443 17 : tree *flag = var_flags.get (var);
3444 34 : if (!flag)
3445 17 : continue;
3446 0 : if (tree cleanup = cxx_maybe_build_cleanup (var, tf_warning_or_error))
3447 : {
3448 0 : tree cond_cleanup = begin_if_stmt ();
3449 0 : finish_if_stmt_cond (*flag, cond_cleanup);
3450 0 : finish_expr_stmt (cleanup);
3451 0 : finish_then_clause (cond_cleanup);
3452 0 : finish_if_stmt (cond_cleanup);
3453 : }
3454 : }
3455 17 : final_actions = pop_stmt_list (final_actions);
3456 17 : tree try_finally
3457 17 : = build2 (TRY_FINALLY_EXPR, void_type_node, new_if, final_actions);
3458 17 : add_stmt (try_finally);
3459 17 : }
3460 :
3461 : /* Given *STMT, that contains at least one await expression.
3462 :
3463 : The full expression represented in the original source code will contain
3464 : suspension points, but it is still required that the lifetime of temporary
3465 : values extends to the end of the expression.
3466 :
3467 : We already have a mechanism to 'promote' user-authored local variables
3468 : to a coroutine frame counterpart (which allows explicit management of the
3469 : lifetime across suspensions). The transform here re-writes STMT into
3470 : a bind expression, promotes temporary values into local variables in that
3471 : and flattens the statement into a series of cleanups.
3472 :
3473 : Conditional expressions are re-written to regular 'if' statements.
3474 : The cleanups for variables initialized inside a conditional (including
3475 : nested cases) are wrapped in a try-finally clause, with guard variables
3476 : to determine which DTORs need to be run. */
3477 :
3478 : static tree
3479 4173 : maybe_promote_temps (tree *stmt, void *d)
3480 : {
3481 4173 : susp_frame_data *awpts = (susp_frame_data *) d;
3482 :
3483 4173 : location_t sloc = EXPR_LOCATION (*stmt);
3484 4173 : tree expr = *stmt;
3485 : /* Strip off uninteresting wrappers. */
3486 4173 : if (TREE_CODE (expr) == CLEANUP_POINT_EXPR)
3487 4170 : expr = TREE_OPERAND (expr, 0);
3488 4173 : if (TREE_CODE (expr) == EXPR_STMT)
3489 4173 : expr = EXPR_STMT_EXPR (expr);
3490 4173 : if (TREE_CODE (expr) == CONVERT_EXPR
3491 4173 : && VOID_TYPE_P (TREE_TYPE (expr)))
3492 510 : expr = TREE_OPERAND (expr, 0);
3493 4173 : STRIP_NOPS (expr);
3494 :
3495 : /* We walk the statement trees, flattening it into an ordered list of
3496 : variables with initializers and fragments corresponding to compound
3497 : expressions, truth or/and if and ternary conditionals. Conditional
3498 : expressions carry a nested list of fragments for the then and else
3499 : clauses. We anchor to the 'bottom' of the fragment list; we will write
3500 : a cleanup nest with one shell for each variable initialized. */
3501 4173 : var_nest_node *root = new var_nest_node (NULL_TREE, expr, NULL, NULL);
3502 : /* Check to see we didn't promote one twice. */
3503 4173 : hash_set<tree> promoted_vars;
3504 4173 : hash_set<tree> used_temps;
3505 4173 : flatten_await_stmt (root, &promoted_vars, &used_temps, NULL);
3506 :
3507 4173 : gcc_checking_assert (root->next == NULL);
3508 4173 : tree vlist = NULL_TREE;
3509 4173 : var_nest_node *t = root;
3510 : /* We build the bind scope expression from the bottom-up.
3511 : EXPR_LIST holds the inner expression nest at the current cleanup
3512 : level (becoming the final expression list when we've exhausted the
3513 : number of sub-expression fragments). */
3514 4173 : tree expr_list = NULL_TREE;
3515 8708 : do
3516 : {
3517 8708 : tree new_list = push_stmt_list ();
3518 : /* When we have a promoted variable, then add that to the bind scope
3519 : and initialize it. When there's no promoted variable, we just need
3520 : to run the initializer.
3521 : If the initializer is a conditional expression, we need to collect
3522 : and declare any promoted variables nested within it. DTORs for such
3523 : variables must be run conditionally too.
3524 :
3525 : Since here we're synthetically processing code here, we've already
3526 : emitted any Wunused-result warnings. Below, however, we call
3527 : finish_expr_stmt, which will convert its operand to void, and could
3528 : result in such a diagnostic being emitted. To avoid that, convert to
3529 : void ahead of time. */
3530 8708 : if (t->var)
3531 : {
3532 4519 : tree var = t->var;
3533 4519 : DECL_CHAIN (var) = vlist;
3534 4519 : vlist = var;
3535 4519 : add_decl_expr (var);
3536 4519 : if (TREE_CODE (t->init) == COND_EXPR)
3537 0 : process_conditional (t, vlist);
3538 : else
3539 4519 : finish_expr_stmt (convert_to_void (t->init, ICV_STATEMENT, tf_none));
3540 4519 : if (tree cleanup = cxx_maybe_build_cleanup (var, tf_warning_or_error))
3541 : {
3542 2010 : tree cl = build_stmt (sloc, CLEANUP_STMT, expr_list, cleanup, var);
3543 2010 : add_stmt (cl); /* push this onto the level above. */
3544 : }
3545 2509 : else if (expr_list)
3546 : {
3547 2505 : if (TREE_CODE (expr_list) != STATEMENT_LIST)
3548 2255 : add_stmt (expr_list);
3549 250 : else if (!tsi_end_p (tsi_start (expr_list)))
3550 250 : add_stmt (expr_list);
3551 : }
3552 : }
3553 : else
3554 : {
3555 4189 : if (TREE_CODE (t->init) == COND_EXPR)
3556 17 : process_conditional (t, vlist);
3557 : else
3558 4172 : finish_expr_stmt (convert_to_void (t->init, ICV_STATEMENT, tf_none));
3559 4189 : if (expr_list)
3560 : {
3561 24 : if (TREE_CODE (expr_list) != STATEMENT_LIST)
3562 12 : add_stmt (expr_list);
3563 12 : else if (!tsi_end_p (tsi_start (expr_list)))
3564 12 : add_stmt (expr_list);
3565 : }
3566 : }
3567 8708 : expr_list = pop_stmt_list (new_list);
3568 8708 : var_nest_node *old = t;
3569 8708 : t = t->prev;
3570 8708 : delete old;
3571 8708 : } while (t);
3572 :
3573 : /* Now produce the bind expression containing the 'promoted' temporaries
3574 : as its variable list, and the cleanup nest as the statement. */
3575 4173 : tree await_bind = build3_loc (sloc, BIND_EXPR, void_type_node,
3576 : NULL, NULL, NULL);
3577 4173 : BIND_EXPR_BODY (await_bind) = expr_list;
3578 4173 : BIND_EXPR_VARS (await_bind) = nreverse (vlist);
3579 4173 : tree b_block = make_node (BLOCK);
3580 4173 : if (!awpts->block_stack->is_empty ())
3581 : {
3582 4173 : tree s_block = awpts->block_stack->last ();
3583 4173 : if (s_block)
3584 : {
3585 4173 : BLOCK_SUPERCONTEXT (b_block) = s_block;
3586 4173 : BLOCK_CHAIN (b_block) = BLOCK_SUBBLOCKS (s_block);
3587 4173 : BLOCK_SUBBLOCKS (s_block) = b_block;
3588 : }
3589 : }
3590 4173 : BLOCK_VARS (b_block) = BIND_EXPR_VARS (await_bind) ;
3591 4173 : BIND_EXPR_BLOCK (await_bind) = b_block;
3592 4173 : TREE_SIDE_EFFECTS (await_bind) = TREE_SIDE_EFFECTS (BIND_EXPR_BODY (await_bind));
3593 4173 : *stmt = await_bind;
3594 4173 : hash_set<tree> visited;
3595 4173 : return cp_walk_tree (stmt, register_awaits, d, &visited);
3596 4173 : }
3597 :
3598 : /* Relatively lightweight callback to do initial assessment:
3599 : 0) Rewrite some await expressions.
3600 : 1) If the statement/expression contains any await expressions.
3601 : 2) If the statement/expression potentially requires a re-write to handle
3602 : TRUTH_{AND,OR}IF_EXPRs since, in most cases, they will need expansion
3603 : so that the await expressions are not processed in the case of the
3604 : short-circuit arm.
3605 :
3606 : CO_YIELD expressions are re-written to their underlying co_await. */
3607 :
3608 : static tree
3609 158473 : analyze_expression_awaits (tree *stmt, int *do_subtree, void *d)
3610 : {
3611 158473 : susp_frame_data *awpts = (susp_frame_data *) d;
3612 :
3613 158473 : switch (TREE_CODE (*stmt))
3614 : {
3615 : default: return NULL_TREE;
3616 19199 : case CALL_EXPR:
3617 19199 : {
3618 19199 : tree fn = cp_get_callee_fndecl_nofold (*stmt);
3619 : /* Special-cases where we want to re-write await expressions to some
3620 : other value before they are otherwise processed. */
3621 19199 : if (fn && DECL_IS_BUILTIN_CONSTANT_P (fn))
3622 : {
3623 9 : gcc_checking_assert (call_expr_nargs (*stmt) == 1);
3624 9 : tree expr = CALL_EXPR_ARG (*stmt, 0);
3625 9 : if (cp_walk_tree (&expr, find_any_await, nullptr, NULL))
3626 : {
3627 9 : if (TREE_CONSTANT (maybe_constant_value (expr)))
3628 3 : *stmt = integer_one_node;
3629 : else
3630 6 : *stmt = integer_zero_node;
3631 : }
3632 9 : *do_subtree = 0;
3633 : }
3634 19190 : else if (!fn && CALL_EXPR_IFN (*stmt) == IFN_ASSUME)
3635 : {
3636 6 : tree expr = CALL_EXPR_ARG (*stmt, 0);
3637 6 : if (TREE_SIDE_EFFECTS (expr))
3638 : {
3639 6 : location_t loc_e = cp_expr_location (expr);
3640 6 : location_t loc_s = cp_expr_location (*stmt);
3641 6 : location_t loc_n = make_location (loc_e, loc_s, loc_s);
3642 6 : warning_at (loc_n, OPT_Wattributes,"assumption ignored"
3643 : " because it contains an await-expression");
3644 6 : *stmt = build_empty_stmt (loc_n);
3645 : }
3646 : }
3647 : }
3648 : break;
3649 372 : case CO_YIELD_EXPR:
3650 : /* co_yield is syntactic sugar, re-write it to co_await. */
3651 372 : *stmt = TREE_OPERAND (*stmt, 1);
3652 : /* FALLTHROUGH */
3653 4245 : case CO_AWAIT_EXPR:
3654 4245 : awpts->saw_awaits++;
3655 : /* A non-null initializer for the awaiter means we need to expand. */
3656 4245 : if (TREE_OPERAND (*stmt, 2))
3657 4192 : awpts->has_awaiter_init = true;
3658 : break;
3659 33 : case TRUTH_ANDIF_EXPR:
3660 33 : case TRUTH_ORIF_EXPR:
3661 33 : {
3662 : /* We don't need special action for awaits in the always-executed
3663 : arm of a TRUTH_IF. */
3664 33 : if (tree res = cp_walk_tree (&TREE_OPERAND (*stmt, 0),
3665 : analyze_expression_awaits, d, NULL))
3666 : return res;
3667 : /* However, if there are await expressions on the conditionally
3668 : executed branch, we must expand the TRUTH_IF to ensure that the
3669 : expanded await expression control-flow is fully contained in the
3670 : conditionally executed code. */
3671 33 : unsigned aw_count = awpts->saw_awaits;
3672 33 : if (tree res = cp_walk_tree (&TREE_OPERAND (*stmt, 1),
3673 : analyze_expression_awaits, d, NULL))
3674 : return res;
3675 33 : if (awpts->saw_awaits > aw_count)
3676 : {
3677 17 : awpts->truth_aoif_to_expand->add (*stmt);
3678 17 : awpts->needs_truth_if_exp = true;
3679 : }
3680 : /* We've done the sub-trees here. */
3681 33 : *do_subtree = 0;
3682 : }
3683 33 : break;
3684 : }
3685 :
3686 : return NULL_TREE; /* Recurse until done. */
3687 : }
3688 :
3689 : /* Given *EXPR
3690 : If EXPR contains a TRUTH_{AND,OR}IF_EXPR, TAOIE with an await expr on
3691 : the conditionally executed branch, change this in a ternary operator.
3692 :
3693 : bool not_expr = TAOIE == TRUTH_ORIF_EXPR ? NOT : NOP;
3694 : not_expr (always-exec expr) ? conditionally-exec expr : not_expr;
3695 :
3696 : Apply this recursively to the condition and the conditionally-exec
3697 : branch. */
3698 :
3699 : struct truth_if_transform {
3700 : tree *orig_stmt;
3701 : tree scratch_var;
3702 : hash_set<tree> *truth_aoif_to_expand;
3703 : };
3704 :
3705 : static tree
3706 2398 : expand_one_truth_if (tree *expr, int *do_subtree, void *d)
3707 : {
3708 2398 : truth_if_transform *xform = (truth_if_transform *) d;
3709 :
3710 2398 : bool needs_not = false;
3711 2398 : switch (TREE_CODE (*expr))
3712 : {
3713 : default: break;
3714 7 : case TRUTH_ORIF_EXPR:
3715 7 : needs_not = true;
3716 : /* FALLTHROUGH */
3717 17 : case TRUTH_ANDIF_EXPR:
3718 17 : {
3719 17 : if (!xform->truth_aoif_to_expand->contains (*expr))
3720 : break;
3721 :
3722 17 : location_t sloc = EXPR_LOCATION (*expr);
3723 : /* Transform truth expression into a cond expression with
3724 : * the always-executed arm as the condition.
3725 : * the conditionally-executed arm as the then clause.
3726 : * the 'else' clause is fixed: 'true' for ||,'false' for &&. */
3727 17 : tree cond = TREE_OPERAND (*expr, 0);
3728 17 : tree test1 = TREE_OPERAND (*expr, 1);
3729 17 : tree fixed = needs_not ? boolean_true_node : boolean_false_node;
3730 10 : if (needs_not)
3731 7 : cond = build1 (TRUTH_NOT_EXPR, boolean_type_node, cond);
3732 17 : tree cond_expr
3733 17 : = build3_loc (sloc, COND_EXPR, boolean_type_node,
3734 : cond, test1, fixed);
3735 17 : *expr = cond_expr;
3736 17 : if (tree res = cp_walk_tree (&COND_EXPR_COND (*expr),
3737 : expand_one_truth_if, d, NULL))
3738 : return res;
3739 17 : if (tree res = cp_walk_tree (&COND_EXPR_THEN (*expr),
3740 : expand_one_truth_if, d, NULL))
3741 : return res;
3742 : /* We've manually processed necessary sub-trees here. */
3743 17 : *do_subtree = 0;
3744 : }
3745 17 : break;
3746 : }
3747 : return NULL_TREE;
3748 : }
3749 :
3750 : /* Helper that adds a new variable of VAR_TYPE to a bind scope BIND, the
3751 : name is made up from NAM_ROOT, NAM_VERS. */
3752 :
3753 : static tree
3754 77 : add_var_to_bind (tree& bind, tree var_type,
3755 : const char *nam_root, unsigned nam_vers)
3756 : {
3757 77 : tree b_vars = BIND_EXPR_VARS (bind);
3758 : /* Build a variable to hold the condition, this will be included in the
3759 : frame as a local var. */
3760 77 : char *nam = xasprintf ("__%s_%d", nam_root, nam_vers);
3761 77 : tree newvar = build_lang_decl (VAR_DECL, get_identifier (nam), var_type);
3762 77 : free (nam);
3763 77 : DECL_CHAIN (newvar) = b_vars;
3764 77 : BIND_EXPR_VARS (bind) = newvar;
3765 77 : return newvar;
3766 : }
3767 :
3768 : /* Helper to build and add if (!cond) break; */
3769 :
3770 : static void
3771 41 : coro_build_add_if_not_cond_break (tree cond)
3772 : {
3773 41 : tree if_stmt = begin_if_stmt ();
3774 41 : tree invert = build1 (TRUTH_NOT_EXPR, boolean_type_node, cond);
3775 41 : finish_if_stmt_cond (invert, if_stmt);
3776 41 : finish_break_stmt ();
3777 41 : finish_then_clause (if_stmt);
3778 41 : finish_if_stmt (if_stmt);
3779 41 : }
3780 :
3781 : /* Tree walk callback to replace continue statements with goto label. */
3782 : static tree
3783 893 : replace_continue (tree *stmt, int *do_subtree, void *d)
3784 : {
3785 893 : tree expr = *stmt;
3786 893 : if (TREE_CODE (expr) == CLEANUP_POINT_EXPR)
3787 32 : expr = TREE_OPERAND (expr, 0);
3788 893 : if (CONVERT_EXPR_P (expr) && VOID_TYPE_P (TREE_TYPE (expr)))
3789 32 : expr = TREE_OPERAND (expr, 0);
3790 893 : STRIP_NOPS (expr);
3791 893 : if (!STATEMENT_CLASS_P (expr))
3792 : return NULL_TREE;
3793 :
3794 36 : switch (TREE_CODE (expr))
3795 : {
3796 : /* Unless it's a special case, just walk the subtrees as usual. */
3797 : default: return NULL_TREE;
3798 :
3799 8 : case CONTINUE_STMT:
3800 8 : {
3801 8 : tree *label = (tree *)d;
3802 8 : location_t loc = EXPR_LOCATION (expr);
3803 : /* re-write a continue to goto label. */
3804 8 : *stmt = build_stmt (loc, GOTO_EXPR, *label);
3805 8 : *do_subtree = 0;
3806 8 : return NULL_TREE;
3807 : }
3808 :
3809 : /* Statements that do not require recursion. */
3810 16 : case DECL_EXPR:
3811 16 : case BREAK_STMT:
3812 16 : case GOTO_EXPR:
3813 16 : case LABEL_EXPR:
3814 16 : case CASE_LABEL_EXPR:
3815 16 : case ASM_EXPR:
3816 : /* These must break recursion. */
3817 16 : case FOR_STMT:
3818 16 : case WHILE_STMT:
3819 16 : case DO_STMT:
3820 16 : *do_subtree = 0;
3821 16 : return NULL_TREE;
3822 : }
3823 : }
3824 :
3825 : /* Tree walk callback to analyze, register and pre-process statements that
3826 : contain await expressions. */
3827 :
3828 : static tree
3829 259870 : await_statement_walker (tree *stmt, int *do_subtree, void *d)
3830 : {
3831 259870 : tree res = NULL_TREE;
3832 259870 : susp_frame_data *awpts = (susp_frame_data *) d;
3833 :
3834 : /* Process a statement at a time. */
3835 259870 : if (TREE_CODE (*stmt) == BIND_EXPR)
3836 : {
3837 : /* For conditional expressions, we might wish to add an artificial var
3838 : to their containing bind expr. */
3839 3523 : vec_safe_push (awpts->bind_stack, *stmt);
3840 : /* We might need to insert a new bind expression, and want to link it
3841 : into the correct scope, so keep a note of the current block scope. */
3842 3523 : tree blk = BIND_EXPR_BLOCK (*stmt);
3843 3523 : vec_safe_push (awpts->block_stack, blk);
3844 3523 : res = cp_walk_tree (&BIND_EXPR_BODY (*stmt), await_statement_walker,
3845 : d, NULL);
3846 3523 : awpts->block_stack->pop ();
3847 3523 : awpts->bind_stack->pop ();
3848 3523 : *do_subtree = 0; /* Done subtrees. */
3849 3523 : return res;
3850 : }
3851 256347 : else if (TREE_CODE (*stmt) == STATEMENT_LIST)
3852 : {
3853 50592 : for (tree &s : tsi_range (*stmt))
3854 : {
3855 41233 : res = cp_walk_tree (&s, await_statement_walker,
3856 : d, NULL);
3857 41233 : if (res)
3858 259870 : return res;
3859 : }
3860 9359 : *do_subtree = 0; /* Done subtrees. */
3861 9359 : return NULL_TREE;
3862 : }
3863 :
3864 : /* We have something to be handled as a single statement. We have to handle
3865 : a few statements specially where await statements have to be moved out of
3866 : constructs. */
3867 246988 : tree expr = *stmt;
3868 246988 : if (TREE_CODE (*stmt) == CLEANUP_POINT_EXPR)
3869 19236 : expr = TREE_OPERAND (expr, 0);
3870 246988 : STRIP_NOPS (expr);
3871 :
3872 246988 : if (STATEMENT_CLASS_P (expr))
3873 27529 : switch (TREE_CODE (expr))
3874 : {
3875 : /* Unless it's a special case, just walk the subtrees as usual. */
3876 : default: return NULL_TREE;
3877 :
3878 : /* When we have a conditional expression, which contains one or more
3879 : await expressions, we have to break the condition out into a
3880 : regular statement so that the control flow introduced by the await
3881 : transforms can be implemented. */
3882 1936 : case IF_STMT:
3883 1936 : {
3884 1936 : tree *await_ptr;
3885 1936 : hash_set<tree> visited;
3886 : /* Transform 'if (cond with awaits) then stmt1 else stmt2' into
3887 : bool cond = cond with awaits.
3888 : if (cond) then stmt1 else stmt2. */
3889 1936 : tree if_stmt = *stmt;
3890 : /* We treat the condition as if it was a stand-alone statement,
3891 : to see if there are any await expressions which will be analyzed
3892 : and registered. */
3893 1936 : if (!(cp_walk_tree (&IF_COND (if_stmt),
3894 : find_any_await, &await_ptr, &visited)))
3895 : return NULL_TREE; /* Nothing special to do here. */
3896 :
3897 67 : gcc_checking_assert (!awpts->bind_stack->is_empty());
3898 67 : tree& bind_expr = awpts->bind_stack->last ();
3899 134 : tree newvar = add_var_to_bind (bind_expr, boolean_type_node,
3900 67 : "ifcd", awpts->cond_number++);
3901 67 : tree insert_list = push_stmt_list ();
3902 67 : tree cond_inner = IF_COND (if_stmt);
3903 67 : if (TREE_CODE (cond_inner) == CLEANUP_POINT_EXPR)
3904 67 : cond_inner = TREE_OPERAND (cond_inner, 0);
3905 67 : add_decl_expr (newvar);
3906 67 : location_t sloc = EXPR_LOCATION (IF_COND (if_stmt));
3907 : /* We want to initialize the new variable with the expression
3908 : that contains the await(s) and potentially also needs to
3909 : have truth_if expressions expanded. */
3910 67 : tree new_s = cp_build_init_expr (sloc, newvar, cond_inner);
3911 67 : finish_expr_stmt (new_s);
3912 67 : IF_COND (if_stmt) = newvar;
3913 67 : add_stmt (if_stmt);
3914 67 : *stmt = pop_stmt_list (insert_list);
3915 : /* So now walk the new statement list. */
3916 67 : res = cp_walk_tree (stmt, await_statement_walker, d, NULL);
3917 67 : *do_subtree = 0; /* Done subtrees. */
3918 67 : return res;
3919 1936 : }
3920 137 : break;
3921 137 : case FOR_STMT:
3922 137 : {
3923 137 : tree *await_ptr;
3924 137 : hash_set<tree> visited;
3925 : /* for loops only need special treatment if the condition or the
3926 : iteration expression contain a co_await. */
3927 137 : tree for_stmt = *stmt;
3928 : /* At present, the FE always generates a separate initializer for
3929 : the FOR_INIT_STMT, when the expression has an await. Check that
3930 : this assumption holds in the future. */
3931 137 : gcc_checking_assert
3932 : (!(cp_walk_tree (&FOR_INIT_STMT (for_stmt), find_any_await,
3933 : &await_ptr, &visited)));
3934 :
3935 137 : visited.empty ();
3936 137 : bool for_cond_await
3937 137 : = cp_walk_tree (&FOR_COND (for_stmt), find_any_await,
3938 : &await_ptr, &visited);
3939 :
3940 137 : visited.empty ();
3941 137 : bool for_expr_await
3942 137 : = cp_walk_tree (&FOR_EXPR (for_stmt), find_any_await,
3943 : &await_ptr, &visited);
3944 :
3945 : /* If the condition has an await, then we will need to rewrite the
3946 : loop as
3947 : for (init expression;true;iteration expression) {
3948 : condition = await expression;
3949 : if (condition)
3950 : break;
3951 : ...
3952 : }
3953 : */
3954 137 : if (for_cond_await)
3955 : {
3956 19 : tree insert_list = push_stmt_list ();
3957 : /* This will be expanded when the revised body is handled. */
3958 19 : coro_build_add_if_not_cond_break (FOR_COND (for_stmt));
3959 : /* .. add the original for body. */
3960 19 : add_stmt (FOR_BODY (for_stmt));
3961 : /* To make the new for body. */
3962 19 : FOR_BODY (for_stmt) = pop_stmt_list (insert_list);
3963 19 : FOR_COND (for_stmt) = boolean_true_node;
3964 : }
3965 : /* If the iteration expression has an await, it's a bit more
3966 : tricky.
3967 : for (init expression;condition;) {
3968 : ...
3969 : iteration_expr_label:
3970 : iteration expression with await;
3971 : }
3972 : but, then we will need to re-write any continue statements into
3973 : 'goto iteration_expr_label:'.
3974 : */
3975 137 : if (for_expr_await)
3976 : {
3977 16 : location_t sloc = EXPR_LOCATION (FOR_EXPR (for_stmt));
3978 16 : tree insert_list = push_stmt_list ();
3979 : /* The original for body. */
3980 16 : add_stmt (FOR_BODY (for_stmt));
3981 16 : char *buf = xasprintf ("for.iter.expr.%u", awpts->cond_number++);
3982 16 : tree it_expr_label
3983 16 : = create_named_label_with_ctx (sloc, buf, NULL_TREE);
3984 16 : free (buf);
3985 16 : add_stmt (build_stmt (sloc, LABEL_EXPR, it_expr_label));
3986 16 : tree for_expr = FOR_EXPR (for_stmt);
3987 : /* Present the iteration expression as a statement. */
3988 16 : if (TREE_CODE (for_expr) == CLEANUP_POINT_EXPR)
3989 16 : for_expr = TREE_OPERAND (for_expr, 0);
3990 16 : STRIP_NOPS (for_expr);
3991 16 : finish_expr_stmt (for_expr);
3992 16 : FOR_EXPR (for_stmt) = NULL_TREE;
3993 16 : FOR_BODY (for_stmt) = pop_stmt_list (insert_list);
3994 : /* rewrite continue statements to goto label. */
3995 16 : hash_set<tree> visited_continue;
3996 16 : if ((res = cp_walk_tree (&FOR_BODY (for_stmt),
3997 : replace_continue, &it_expr_label, &visited_continue)))
3998 0 : return res;
3999 16 : }
4000 :
4001 : /* So now walk the body statement (list), if there were no await
4002 : expressions, then this handles the original body - and either
4003 : way we will have finished with this statement. */
4004 137 : res = cp_walk_tree (&FOR_BODY (for_stmt),
4005 : await_statement_walker, d, NULL);
4006 137 : *do_subtree = 0; /* Done subtrees. */
4007 137 : return res;
4008 137 : }
4009 14 : break;
4010 14 : case WHILE_STMT:
4011 14 : {
4012 : /* We turn 'while (cond with awaits) stmt' into
4013 : while (true) {
4014 : if (!(cond with awaits))
4015 : break;
4016 : stmt..
4017 : } */
4018 14 : tree *await_ptr;
4019 14 : hash_set<tree> visited;
4020 14 : tree while_stmt = *stmt;
4021 14 : if (!(cp_walk_tree (&WHILE_COND (while_stmt),
4022 : find_any_await, &await_ptr, &visited)))
4023 : return NULL_TREE; /* Nothing special to do here. */
4024 :
4025 14 : tree insert_list = push_stmt_list ();
4026 14 : coro_build_add_if_not_cond_break (WHILE_COND (while_stmt));
4027 : /* The original while body. */
4028 14 : add_stmt (WHILE_BODY (while_stmt));
4029 : /* The new while body. */
4030 14 : WHILE_BODY (while_stmt) = pop_stmt_list (insert_list);
4031 14 : WHILE_COND (while_stmt) = boolean_true_node;
4032 : /* So now walk the new statement list. */
4033 14 : res = cp_walk_tree (&WHILE_BODY (while_stmt),
4034 : await_statement_walker, d, NULL);
4035 14 : *do_subtree = 0; /* Done subtrees. */
4036 14 : return res;
4037 14 : }
4038 8 : break;
4039 8 : case DO_STMT:
4040 8 : {
4041 : /* We turn do stmt while (cond with awaits) into:
4042 : do {
4043 : stmt..
4044 : if (!(cond with awaits))
4045 : break;
4046 : } while (true); */
4047 8 : tree do_stmt = *stmt;
4048 8 : tree *await_ptr;
4049 8 : hash_set<tree> visited;
4050 8 : if (!(cp_walk_tree (&DO_COND (do_stmt),
4051 : find_any_await, &await_ptr, &visited)))
4052 : return NULL_TREE; /* Nothing special to do here. */
4053 :
4054 8 : tree insert_list = push_stmt_list ();
4055 : /* The original do stmt body. */
4056 8 : add_stmt (DO_BODY (do_stmt));
4057 8 : coro_build_add_if_not_cond_break (DO_COND (do_stmt));
4058 : /* The new while body. */
4059 8 : DO_BODY (do_stmt) = pop_stmt_list (insert_list);
4060 8 : DO_COND (do_stmt) = boolean_true_node;
4061 : /* So now walk the new statement list. */
4062 8 : res = cp_walk_tree (&DO_BODY (do_stmt), await_statement_walker,
4063 : d, NULL);
4064 8 : *do_subtree = 0; /* Done subtrees. */
4065 8 : return res;
4066 8 : }
4067 23 : break;
4068 23 : case SWITCH_STMT:
4069 23 : {
4070 : /* We turn 'switch (cond with awaits) stmt' into
4071 : switch_type cond = cond with awaits
4072 : switch (cond) stmt. */
4073 23 : tree sw_stmt = *stmt;
4074 23 : tree *await_ptr;
4075 23 : hash_set<tree> visited;
4076 23 : if (!(cp_walk_tree (&SWITCH_STMT_COND (sw_stmt),
4077 : find_any_await, &await_ptr, &visited)))
4078 : return NULL_TREE; /* Nothing special to do here. */
4079 :
4080 10 : gcc_checking_assert (!awpts->bind_stack->is_empty());
4081 : /* Build a variable to hold the condition, this will be
4082 : included in the frame as a local var. */
4083 10 : tree& bind_expr = awpts->bind_stack->last ();
4084 10 : tree sw_type = SWITCH_STMT_TYPE (sw_stmt);
4085 20 : tree newvar = add_var_to_bind (bind_expr, sw_type, "swch",
4086 10 : awpts->cond_number++);
4087 10 : tree insert_list = push_stmt_list ();
4088 10 : add_decl_expr (newvar);
4089 :
4090 10 : tree cond_inner = SWITCH_STMT_COND (sw_stmt);
4091 10 : if (TREE_CODE (cond_inner) == CLEANUP_POINT_EXPR)
4092 10 : cond_inner = TREE_OPERAND (cond_inner, 0);
4093 10 : location_t sloc = EXPR_LOCATION (SWITCH_STMT_COND (sw_stmt));
4094 10 : tree new_s = cp_build_init_expr (sloc, newvar,
4095 : cond_inner);
4096 10 : finish_expr_stmt (new_s);
4097 10 : SWITCH_STMT_COND (sw_stmt) = newvar;
4098 : /* Now add the switch statement with the condition re-
4099 : written to use the local var. */
4100 10 : add_stmt (sw_stmt);
4101 10 : *stmt = pop_stmt_list (insert_list);
4102 : /* Process the expanded list. */
4103 10 : res = cp_walk_tree (stmt, await_statement_walker,
4104 : d, NULL);
4105 10 : *do_subtree = 0; /* Done subtrees. */
4106 10 : return res;
4107 23 : }
4108 1511 : break;
4109 1511 : case CO_RETURN_EXPR:
4110 1511 : {
4111 : /* Expand the co_return as per [stmt.return.coroutine]
4112 : - for co_return;
4113 : { p.return_void (); goto final_suspend; }
4114 : - for co_return [void expr];
4115 : { expr; p.return_void(); goto final_suspend;}
4116 : - for co_return [non void expr];
4117 : { p.return_value(expr); goto final_suspend; } */
4118 1511 : location_t loc = EXPR_LOCATION (expr);
4119 1511 : tree call = TREE_OPERAND (expr, 1);
4120 1511 : expr = TREE_OPERAND (expr, 0);
4121 1511 : tree ret_list = push_stmt_list ();
4122 : /* [stmt.return.coroutine], 2.2
4123 : If expr is present and void, it is placed immediately before
4124 : the call for return_void; */
4125 1511 : if (expr && VOID_TYPE_P (TREE_TYPE (expr)))
4126 10 : finish_expr_stmt (expr);
4127 : /* Insert p.return_{void,value(expr)}. */
4128 1511 : finish_expr_stmt (call);
4129 1511 : TREE_USED (awpts->fs_label) = 1;
4130 1511 : add_stmt (build_stmt (loc, GOTO_EXPR, awpts->fs_label));
4131 1511 : *stmt = pop_stmt_list (ret_list);
4132 1511 : res = cp_walk_tree (stmt, await_statement_walker, d, NULL);
4133 : /* Once this is complete, we will have processed subtrees. */
4134 1511 : *do_subtree = 0;
4135 1511 : return res;
4136 : }
4137 1607 : break;
4138 1607 : case HANDLER:
4139 1607 : {
4140 : /* [expr.await] An await-expression shall appear only in a
4141 : potentially-evaluated expression within the compound-statement
4142 : of a function-body outside of a handler. */
4143 1607 : tree *await_ptr;
4144 1607 : hash_set<tree> visited;
4145 1607 : if (!(cp_walk_tree (&HANDLER_BODY (expr), find_any_await,
4146 : &await_ptr, &visited)))
4147 : return NULL_TREE; /* All OK. */
4148 3 : location_t loc = EXPR_LOCATION (*await_ptr);
4149 3 : error_at (loc, "await expressions are not permitted in handlers");
4150 3 : return NULL_TREE; /* This is going to fail later anyway. */
4151 1607 : }
4152 219459 : break;
4153 : }
4154 219459 : else if (EXPR_P (expr))
4155 : {
4156 86411 : hash_set<tree> visited;
4157 86411 : tree *await_ptr;
4158 86411 : if (!(cp_walk_tree (stmt, find_any_await, &await_ptr, &visited)))
4159 : return NULL_TREE; /* Nothing special to do here. */
4160 :
4161 4188 : visited.empty ();
4162 4188 : awpts->saw_awaits = 0;
4163 4188 : hash_set<tree> truth_aoif_to_expand;
4164 4188 : awpts->truth_aoif_to_expand = &truth_aoif_to_expand;
4165 4188 : awpts->needs_truth_if_exp = false;
4166 4188 : awpts->has_awaiter_init = false;
4167 4188 : if ((res = cp_walk_tree (stmt, analyze_expression_awaits, d, &visited)))
4168 : return res;
4169 4188 : *do_subtree = 0; /* Done subtrees. */
4170 4188 : if (!awpts->saw_awaits)
4171 : return NULL_TREE; /* Nothing special to do here. */
4172 :
4173 4173 : if (awpts->needs_truth_if_exp)
4174 : {
4175 : /* If a truth-and/or-if expression has an await expression in the
4176 : conditionally-taken branch, then it must be rewritten into a
4177 : regular conditional. */
4178 17 : truth_if_transform xf = {stmt, NULL_TREE, &truth_aoif_to_expand};
4179 17 : if ((res = cp_walk_tree (stmt, expand_one_truth_if, &xf, NULL)))
4180 0 : return res;
4181 : }
4182 : /* Process this statement, which contains at least one await expression
4183 : to 'promote' temporary values to a coroutine frame slot. */
4184 4173 : return maybe_promote_temps (stmt, d);
4185 90599 : }
4186 : /* Continue recursion, if needed. */
4187 : return res;
4188 : }
4189 :
4190 : /* For figuring out what param usage we have. */
4191 :
4192 : struct param_frame_data
4193 : {
4194 : tree *field_list;
4195 : hash_map<tree, param_info> *param_uses;
4196 : hash_set<tree *> *visited;
4197 : location_t loc;
4198 : bool param_seen;
4199 : };
4200 :
4201 : /* A tree walk callback that rewrites each parm use to the local variable
4202 : that represents its copy in the frame. */
4203 :
4204 : static tree
4205 107150 : rewrite_param_uses (tree *stmt, int *do_subtree ATTRIBUTE_UNUSED, void *d)
4206 : {
4207 107150 : param_frame_data *data = (param_frame_data *) d;
4208 :
4209 : /* For lambda closure content, we have to look specifically. */
4210 107150 : if (VAR_P (*stmt) && DECL_HAS_VALUE_EXPR_P (*stmt))
4211 : {
4212 644 : tree t = DECL_VALUE_EXPR (*stmt);
4213 644 : return cp_walk_tree (&t, rewrite_param_uses, d, NULL);
4214 : }
4215 :
4216 106506 : if (unevaluated_p (TREE_CODE (*stmt)))
4217 : {
4218 : /* No odr-uses in unevaluated operands. */
4219 3 : *do_subtree = 0;
4220 3 : return NULL_TREE;
4221 : }
4222 :
4223 106503 : if (TREE_CODE (*stmt) != PARM_DECL)
4224 : return NULL_TREE;
4225 :
4226 : /* If we already saw the containing expression, then we're done. */
4227 925 : if (data->visited->add (stmt))
4228 : return NULL_TREE;
4229 :
4230 925 : bool existed;
4231 925 : param_info &parm = data->param_uses->get_or_insert (*stmt, &existed);
4232 925 : gcc_checking_assert (existed);
4233 :
4234 925 : *stmt = parm.copy_var;
4235 925 : return NULL_TREE;
4236 : }
4237 :
4238 : /* Build up a set of info that determines how each param copy will be
4239 : handled. We store this in a hash map so that we can access it from
4240 : a tree walk callback that re-writes the original parameters to their
4241 : copies. */
4242 :
4243 : void
4244 1610 : cp_coroutine_transform::analyze_fn_parms ()
4245 : {
4246 1610 : if (!DECL_ARGUMENTS (orig_fn_decl))
4247 : return;
4248 :
4249 : /* Build a hash map with an entry for each param.
4250 : The key is the param tree.
4251 : Then we have an entry for the frame field name.
4252 : Then a cache for the field ref when we come to use it.
4253 : Then a tree list of the uses.
4254 : The second two entries start out empty - and only get populated
4255 : when we see uses. */
4256 972 : bool lambda_p = LAMBDA_FUNCTION_P (orig_fn_decl);
4257 :
4258 : /* Count the param copies from 1 as per the std. */
4259 775 : unsigned parm_num = 1;
4260 1775 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
4261 1000 : ++parm_num, arg = DECL_CHAIN (arg))
4262 : {
4263 1000 : bool existed;
4264 1000 : param_info &parm = param_uses.get_or_insert (arg, &existed);
4265 1000 : gcc_checking_assert (!existed);
4266 1000 : parm.body_uses = NULL;
4267 1000 : tree actual_type = TREE_TYPE (arg);
4268 1000 : actual_type = complete_type_or_else (actual_type, orig_fn_decl);
4269 1000 : if (actual_type == NULL_TREE)
4270 0 : actual_type = error_mark_node;
4271 1000 : parm.orig_type = actual_type;
4272 1000 : parm.by_ref = parm.pt_ref = parm.rv_ref = false;
4273 1000 : if (TREE_CODE (actual_type) == REFERENCE_TYPE)
4274 : {
4275 : /* If the user passes by reference, then we will save the
4276 : pointer to the original. As noted in
4277 : [dcl.fct.def.coroutine] / 13, if the lifetime of the
4278 : referenced item ends and then the coroutine is resumed,
4279 : we have UB; well, the user asked for it. */
4280 131 : if (TYPE_REF_IS_RVALUE (actual_type))
4281 41 : parm.rv_ref = true;
4282 : else
4283 90 : parm.pt_ref = true;
4284 : }
4285 869 : else if (TYPE_REF_P (DECL_ARG_TYPE (arg)))
4286 115 : parm.by_ref = true;
4287 :
4288 1000 : parm.frame_type = actual_type;
4289 :
4290 1000 : parm.this_ptr = is_this_parameter (arg);
4291 1000 : parm.lambda_cobj = lambda_p && DECL_NAME (arg) == closure_identifier;
4292 :
4293 1000 : tree name = DECL_NAME (arg);
4294 1000 : if (!name)
4295 : {
4296 78 : char *buf = xasprintf ("_Coro_q%u___unnamed", parm_num);
4297 78 : name = get_identifier (buf);
4298 78 : free (buf);
4299 : }
4300 1000 : parm.field_id = name;
4301 1000 : if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (parm.frame_type))
4302 115 : parm.trivial_dtor = false;
4303 : else
4304 885 : parm.trivial_dtor = true;
4305 : }
4306 : }
4307 :
4308 : /* Small helper for the repetitive task of adding a new field to the coro
4309 : frame type. */
4310 :
4311 : static tree
4312 17692 : coro_make_frame_entry (tree *field_list, const char *name, tree fld_type,
4313 : location_t loc)
4314 : {
4315 17692 : tree id = get_identifier (name);
4316 17692 : tree decl = build_decl (loc, FIELD_DECL, id, fld_type);
4317 17692 : DECL_CHAIN (decl) = *field_list;
4318 17692 : *field_list = decl;
4319 17692 : return id;
4320 : }
4321 :
4322 : /* A tree-walk callback that processes one bind expression noting local
4323 : variables, and making a coroutine frame slot available for those that
4324 : need it, so that they can be 'promoted' across suspension points. */
4325 :
4326 : static tree
4327 402710 : register_local_var_uses (tree *stmt, int *do_subtree, void *d)
4328 : {
4329 402710 : if (TREE_CODE (*stmt) != BIND_EXPR)
4330 : return NULL_TREE;
4331 :
4332 7702 : local_vars_frame_data *lvd = (local_vars_frame_data *) d;
4333 :
4334 : /* As we enter a bind expression - record the vars there and then recurse.
4335 : As we exit drop the nest depth.
4336 : The bind index is a growing count of how many bind indices we've seen.
4337 : We build a space in the frame for each local var. */
4338 :
4339 7702 : tree lvar;
4340 7702 : unsigned serial = 0;
4341 25565 : for (lvar = BIND_EXPR_VARS (*stmt); lvar != NULL; lvar = DECL_CHAIN (lvar))
4342 : {
4343 17863 : bool existed;
4344 17863 : local_var_info &local_var
4345 17863 : = lvd->local_var_uses->get_or_insert (lvar, &existed);
4346 17863 : gcc_checking_assert (!existed);
4347 17863 : local_var.def_loc = DECL_SOURCE_LOCATION (lvar);
4348 17863 : tree lvtype = TREE_TYPE (lvar);
4349 17863 : local_var.frame_type = lvtype;
4350 17863 : local_var.field_idx = local_var.field_id = NULL_TREE;
4351 :
4352 : /* Make sure that we only present vars to the tests below. */
4353 17863 : if (TREE_CODE (lvar) != PARM_DECL
4354 17863 : && TREE_CODE (lvar) != VAR_DECL)
4355 171 : continue;
4356 :
4357 : /* We don't move static vars into the frame. */
4358 17816 : local_var.is_static = TREE_STATIC (lvar);
4359 17816 : if (local_var.is_static)
4360 5 : continue;
4361 :
4362 17811 : poly_uint64 size;
4363 17814 : if (TREE_CODE (lvtype) == ARRAY_TYPE
4364 17811 : && !poly_int_tree_p (DECL_SIZE_UNIT (lvar), &size))
4365 : {
4366 3 : sorry_at (local_var.def_loc, "variable length arrays are not"
4367 : " yet supported in coroutines");
4368 : /* Ignore it, this is broken anyway. */
4369 3 : continue;
4370 : }
4371 :
4372 17808 : lvd->local_var_seen = true;
4373 : /* If this var is a lambda capture proxy, we want to leave it alone,
4374 : and later rewrite the DECL_VALUE_EXPR to indirect through the
4375 : frame copy of the pointer to the lambda closure object. */
4376 17808 : local_var.is_lambda_capture = is_capture_proxy (lvar);
4377 17808 : if (local_var.is_lambda_capture)
4378 109 : continue;
4379 :
4380 : /* If a variable has a value expression, then that's what needs
4381 : to be processed. */
4382 17699 : local_var.has_value_expr_p = DECL_HAS_VALUE_EXPR_P (lvar);
4383 17699 : if (local_var.has_value_expr_p)
4384 7 : continue;
4385 :
4386 : /* Make names depth+index unique, so that we can support nested
4387 : scopes with identically named locals and still be able to
4388 : identify them in the coroutine frame. */
4389 17692 : tree lvname = DECL_NAME (lvar);
4390 17692 : char *buf = NULL;
4391 :
4392 : /* The outermost bind scope contains the artificial variables that
4393 : we inject to implement the coro state machine. We want to be able
4394 : to inspect these in debugging. */
4395 17692 : if (lvname != NULL_TREE && lvd->nest_depth == 0)
4396 12248 : buf = xasprintf ("%s", IDENTIFIER_POINTER (lvname));
4397 5396 : else if (lvname != NULL_TREE)
4398 5396 : buf = xasprintf ("%s_%u_%u", IDENTIFIER_POINTER (lvname),
4399 : lvd->nest_depth, lvd->bind_indx);
4400 : else
4401 48 : buf = xasprintf ("_D%u_%u_%u", lvd->nest_depth, lvd->bind_indx,
4402 : serial++);
4403 :
4404 : /* TODO: Figure out if we should build a local type that has any
4405 : excess alignment or size from the original decl. */
4406 17692 : local_var.field_id = coro_make_frame_entry (lvd->field_list, buf,
4407 : lvtype, lvd->loc);
4408 17692 : free (buf);
4409 : /* We don't walk any of the local var sub-trees, they won't contain
4410 : any bind exprs. */
4411 : }
4412 7702 : lvd->bind_indx++;
4413 7702 : lvd->nest_depth++;
4414 : /* Ensure we only visit each expression once. */
4415 7702 : cp_walk_tree_without_duplicates (&BIND_EXPR_BODY (*stmt),
4416 : register_local_var_uses, d);
4417 7702 : *do_subtree = 0; /* We've done this. */
4418 7702 : lvd->nest_depth--;
4419 7702 : return NULL_TREE;
4420 : }
4421 :
4422 : /* Build, return FUNCTION_DECL node based on ORIG with a type FN_TYPE which has
4423 : a single argument of type CORO_FRAME_PTR. Build the actor function if
4424 : ACTOR_P is true, otherwise the destroy. */
4425 :
4426 : static tree
4427 3220 : coro_build_actor_or_destroy_function (tree orig, tree fn_type,
4428 : tree coro_frame_ptr, bool actor_p)
4429 : {
4430 3220 : location_t loc = DECL_SOURCE_LOCATION (orig);
4431 3220 : tree fn
4432 3220 : = build_lang_decl (FUNCTION_DECL, copy_node (DECL_NAME (orig)), fn_type);
4433 :
4434 : /* Allow for locating the ramp (original) function from this one. */
4435 3220 : coro_set_ramp_function (fn, orig);
4436 :
4437 3220 : DECL_CONTEXT (fn) = DECL_CONTEXT (orig);
4438 3220 : DECL_SOURCE_LOCATION (fn) = loc;
4439 3220 : DECL_ARTIFICIAL (fn) = true;
4440 3220 : DECL_INITIAL (fn) = error_mark_node;
4441 3220 : DECL_COROUTINE_P (fn) = true;
4442 :
4443 3220 : tree id = get_identifier ("frame_ptr");
4444 3220 : tree fp = build_lang_decl (PARM_DECL, id, coro_frame_ptr);
4445 3220 : DECL_ARTIFICIAL (fp) = true;
4446 3220 : DECL_CONTEXT (fp) = fn;
4447 3220 : DECL_ARG_TYPE (fp) = type_passed_as (coro_frame_ptr);
4448 3220 : DECL_ARGUMENTS (fn) = fp;
4449 :
4450 : /* Copy selected attributes from the original function. */
4451 3220 : TREE_USED (fn) = TREE_USED (orig);
4452 3220 : if (DECL_SECTION_NAME (orig))
4453 0 : set_decl_section_name (fn, orig);
4454 : /* Copy any alignment that the FE added. */
4455 3220 : if (DECL_ALIGN (orig))
4456 3220 : SET_DECL_ALIGN (fn, DECL_ALIGN (orig));
4457 : /* Copy any alignment the user added. */
4458 3220 : DECL_USER_ALIGN (fn) = DECL_USER_ALIGN (orig);
4459 : /* Apply attributes from the original fn. */
4460 3220 : DECL_ATTRIBUTES (fn) = copy_list (DECL_ATTRIBUTES (orig));
4461 :
4462 : /* A void return. */
4463 3220 : tree resdecl = build_decl (loc, RESULT_DECL, 0, void_type_node);
4464 3220 : DECL_CONTEXT (resdecl) = fn;
4465 3220 : DECL_ARTIFICIAL (resdecl) = 1;
4466 3220 : DECL_IGNORED_P (resdecl) = 1;
4467 3220 : DECL_RESULT (fn) = resdecl;
4468 :
4469 : /* Set up a means to find out if a decl is one of the helpers and, if so,
4470 : which one. */
4471 3220 : if (coroutine_info *info = get_coroutine_info (orig))
4472 : {
4473 3220 : gcc_checking_assert ((actor_p && info->actor_decl == NULL_TREE)
4474 : || info->destroy_decl == NULL_TREE);
4475 3220 : if (actor_p)
4476 1610 : info->actor_decl = fn;
4477 : else
4478 1610 : info->destroy_decl = fn;
4479 : }
4480 3220 : return fn;
4481 : }
4482 :
4483 : /* Re-write the body as per [dcl.fct.def.coroutine] / 5. */
4484 :
4485 : void
4486 1610 : cp_coroutine_transform::wrap_original_function_body ()
4487 : {
4488 : /* Avoid the code here attaching a location that makes the debugger jump. */
4489 1610 : iloc_sentinel stable_input_loc (fn_start);
4490 1610 : location_t loc = fn_start;
4491 :
4492 : /* This will be our new outer scope. */
4493 1610 : tree update_body
4494 1610 : = build3_loc (loc, BIND_EXPR, void_type_node, NULL, NULL, NULL);
4495 1610 : tree top_block = make_node (BLOCK);
4496 1610 : BIND_EXPR_BLOCK (update_body) = top_block;
4497 1610 : BIND_EXPR_BODY (update_body) = push_stmt_list ();
4498 :
4499 : /* If the function has a top level bind expression, then connect that
4500 : after first making sure we give it a new block. */
4501 1610 : tree first = expr_first (coroutine_body);
4502 1610 : if (first && TREE_CODE (first) == BIND_EXPR)
4503 : {
4504 646 : tree block = BIND_EXPR_BLOCK (first);
4505 646 : gcc_checking_assert (block);
4506 646 : gcc_checking_assert (BLOCK_SUPERCONTEXT (block) == NULL_TREE);
4507 646 : gcc_checking_assert (BLOCK_CHAIN (block) == NULL_TREE);
4508 : /* Replace the top block to avoid issues with locations for args
4509 : appearing to be in a non-existent place. */
4510 646 : tree replace_blk = make_node (BLOCK);
4511 646 : BLOCK_VARS (replace_blk) = BLOCK_VARS (block);
4512 646 : BLOCK_SUBBLOCKS (replace_blk) = BLOCK_SUBBLOCKS (block);
4513 895 : for (tree b = BLOCK_SUBBLOCKS (replace_blk); b; b = BLOCK_CHAIN (b))
4514 249 : BLOCK_SUPERCONTEXT (b) = replace_blk;
4515 646 : BIND_EXPR_BLOCK (first) = replace_blk;
4516 : /* The top block has one child, so far, and we have now got a
4517 : superblock. */
4518 646 : BLOCK_SUPERCONTEXT (replace_blk) = top_block;
4519 646 : BLOCK_SUBBLOCKS (top_block) = replace_blk;
4520 646 : }
4521 : else
4522 : {
4523 : /* We are missing a top level BIND_EXPR. We need one to ensure that we
4524 : don't shuffle around the coroutine frame and corrupt it. */
4525 964 : tree bind_wrap = build3_loc (loc, BIND_EXPR, void_type_node,
4526 : NULL, NULL, NULL);
4527 964 : BIND_EXPR_BODY (bind_wrap) = coroutine_body;
4528 : /* Ensure we have a block to connect up the scopes. */
4529 964 : tree new_blk = make_node (BLOCK);
4530 964 : BIND_EXPR_BLOCK (bind_wrap) = new_blk;
4531 964 : BLOCK_SUBBLOCKS (top_block) = new_blk;
4532 964 : coroutine_body = bind_wrap;
4533 : }
4534 :
4535 : /* Wrap the function body in a try {} catch (...) {} block, if exceptions
4536 : are enabled. */
4537 1610 : tree var_list = NULL_TREE;
4538 :
4539 : /* [stmt.return.coroutine] / 3
4540 : If p.return_void() is a valid expression, flowing off the end of a
4541 : coroutine is equivalent to a co_return with no operand; otherwise
4542 : flowing off the end of a coroutine results in undefined behavior. */
4543 1610 : tree return_void
4544 1610 : = get_coroutine_return_void_expr (orig_fn_decl, loc, false);
4545 :
4546 : /* The pointer to the resume function. */
4547 1610 : tree resume_fn_ptr
4548 1610 : = coro_build_artificial_var (loc, coro_resume_fn_id,
4549 : act_des_fn_ptr_type, orig_fn_decl, NULL_TREE);
4550 1610 : DECL_CHAIN (resume_fn_ptr) = var_list;
4551 1610 : var_list = resume_fn_ptr;
4552 1610 : add_decl_expr (resume_fn_ptr);
4553 :
4554 : /* We will need to be able to set the resume function pointer to nullptr
4555 : to signal that the coroutine is 'done'. */
4556 1610 : tree zero_resume
4557 1610 : = build1 (CONVERT_EXPR, act_des_fn_ptr_type, nullptr_node);
4558 :
4559 : /* The pointer to the destroy function. */
4560 1610 : tree var
4561 1610 : = coro_build_artificial_var (loc, coro_destroy_fn_id,
4562 : act_des_fn_ptr_type, orig_fn_decl, NULL_TREE);
4563 1610 : DECL_CHAIN (var) = var_list;
4564 1610 : var_list = var;
4565 1610 : add_decl_expr (var);
4566 :
4567 : /* The promise was created on demand when parsing we now link it into
4568 : our scope. */
4569 1610 : tree promise = get_coroutine_promise_proxy (orig_fn_decl);
4570 1610 : DECL_CONTEXT (promise) = orig_fn_decl;
4571 1610 : DECL_SOURCE_LOCATION (promise) = loc;
4572 1610 : DECL_CHAIN (promise) = var_list;
4573 1610 : var_list = promise;
4574 1610 : add_decl_expr (promise);
4575 :
4576 : /* If we have function parms, then these will be copied to the coroutine
4577 : frame as per [dcl.fct.def.coroutine] / 13.
4578 : Here, we create a local (proxy) variable for each parm, since the original
4579 : parms will be out of scope once the ramp has finished. The proxy vars will
4580 : get DECL_VALUE_EXPRs pointing to the frame copies, so that we can interact
4581 : with them in the debugger. */
4582 1610 : if (DECL_ARGUMENTS (orig_fn_decl))
4583 : {
4584 : /* Add a local var for each parm. */
4585 1775 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
4586 1000 : arg = DECL_CHAIN (arg))
4587 : {
4588 1000 : param_info *parm_i = param_uses.get (arg);
4589 1000 : gcc_checking_assert (parm_i);
4590 1000 : parm_i->copy_var
4591 1000 : = build_lang_decl (VAR_DECL, parm_i->field_id, TREE_TYPE (arg));
4592 1000 : DECL_SOURCE_LOCATION (parm_i->copy_var) = DECL_SOURCE_LOCATION (arg);
4593 1000 : DECL_CONTEXT (parm_i->copy_var) = orig_fn_decl;
4594 1000 : DECL_ARTIFICIAL (parm_i->copy_var) = true;
4595 1000 : DECL_CHAIN (parm_i->copy_var) = var_list;
4596 1000 : var_list = parm_i->copy_var;
4597 1000 : add_decl_expr (parm_i->copy_var);
4598 : }
4599 :
4600 : /* Now replace all uses of the parms in the function body with the proxy
4601 : vars. We want to this to apply to every instance of param's use, so
4602 : don't include a 'visited' hash_set on the tree walk, however we will
4603 : arrange to visit each containing expression only once. */
4604 775 : hash_set<tree *> visited;
4605 775 : param_frame_data param_data = {NULL, ¶m_uses,
4606 775 : &visited, loc, false};
4607 775 : cp_walk_tree (&coroutine_body, rewrite_param_uses, ¶m_data, NULL);
4608 775 : }
4609 :
4610 : /* We create a resume index, this is initialized in the ramp. */
4611 1610 : resume_idx_var
4612 1610 : = coro_build_artificial_var (loc, coro_resume_index_id,
4613 : short_unsigned_type_node, orig_fn_decl,
4614 : NULL_TREE);
4615 1610 : DECL_CHAIN (resume_idx_var) = var_list;
4616 1610 : var_list = resume_idx_var;
4617 1610 : add_decl_expr (resume_idx_var);
4618 :
4619 1610 : tree coro_frame_refcount
4620 1610 : = coro_build_artificial_var (loc, coro_frame_refcount_id,
4621 : short_unsigned_type_node, orig_fn_decl,
4622 : NULL_TREE);
4623 1610 : DECL_CHAIN (coro_frame_refcount) = var_list;
4624 1610 : var_list = coro_frame_refcount;
4625 1610 : add_decl_expr (coro_frame_refcount);
4626 :
4627 : /* If the coroutine has a frame that needs to be freed, this will be set by
4628 : the ramp. */
4629 1610 : var = coro_build_artificial_var (loc, coro_frame_needs_free_id,
4630 : boolean_type_node, orig_fn_decl, NULL_TREE);
4631 1610 : DECL_CHAIN (var) = var_list;
4632 1610 : var_list = var;
4633 1610 : add_decl_expr (var);
4634 :
4635 : /* We consider that the body has a use of the frame once we start to process
4636 : the initial suspend expression. (the use might be relinquished if we
4637 : encounter an exception before the body is finished). */
4638 1610 : tree body_use
4639 1610 : = build2_loc (loc, PLUS_EXPR, short_unsigned_type_node, coro_frame_refcount,
4640 : build_int_cst (short_unsigned_type_node, 1));
4641 1610 : body_use = cp_build_modify_expr (loc, coro_frame_refcount, NOP_EXPR, body_use,
4642 : tf_warning_or_error);
4643 1610 : finish_expr_stmt (body_use);
4644 1610 : if (flag_exceptions)
4645 : {
4646 : /* Build promise.unhandled_exception(); */
4647 1588 : tree ueh
4648 1588 : = coro_build_promise_expression (orig_fn_decl, promise,
4649 : coro_unhandled_exception_identifier,
4650 : loc, NULL, /*musthave=*/true);
4651 : /* Create and initialize the initial-await-resume-called variable per
4652 : [dcl.fct.def.coroutine] / 5.3. */
4653 1588 : tree i_a_r_c
4654 1588 : = coro_build_artificial_var (loc, coro_frame_i_a_r_c_id,
4655 : boolean_type_node, orig_fn_decl,
4656 : NULL_TREE);
4657 1588 : DECL_CHAIN (i_a_r_c) = var_list;
4658 1588 : var_list = i_a_r_c;
4659 1588 : add_decl_expr (i_a_r_c);
4660 : /* Start the try-catch. */
4661 1588 : tree tcb = build_stmt (loc, TRY_BLOCK, NULL_TREE, NULL_TREE);
4662 1588 : add_stmt (tcb);
4663 1588 : TRY_STMTS (tcb) = push_stmt_list ();
4664 : /* We need a new scope to handle the cleanup for the ramp use that is
4665 : needed for exceptions. */
4666 1588 : tree except_scope = begin_compound_stmt (0);
4667 1588 : current_binding_level->artificial = 1;
4668 1588 : tree release
4669 1588 : = build2_loc (loc, MINUS_EXPR, short_unsigned_type_node,
4670 : coro_frame_refcount, build_int_cst (short_unsigned_type_node, 1));
4671 1588 : release = cp_build_modify_expr (loc, coro_frame_refcount, NOP_EXPR,
4672 : release, tf_warning_or_error);
4673 : /* Once we pass the initial await resume, the cleanup rules on exception
4674 : change so that the responsibility lies with the caller. */
4675 1588 : release = build3 (COND_EXPR, void_type_node, i_a_r_c,
4676 : build_empty_stmt (loc), release);
4677 1588 : push_cleanup (NULL_TREE, release, /*ehonly*/true);
4678 : /* Add the initial await to the start of the user-authored function. */
4679 1588 : finish_expr_stmt (initial_await);
4680 : /* End the scope that handles the remove of frame-use on exception. */
4681 1588 : finish_compound_stmt (except_scope);
4682 :
4683 : /* Append the original function body. */
4684 1588 : add_stmt (coroutine_body);
4685 :
4686 1588 : if (return_void)
4687 668 : add_stmt (return_void);
4688 1588 : TRY_STMTS (tcb) = pop_stmt_list (TRY_STMTS (tcb));
4689 1588 : TRY_HANDLERS (tcb) = push_stmt_list ();
4690 : /* Mimic what the parser does for the catch. */
4691 1588 : tree handler = begin_handler ();
4692 1588 : finish_handler_parms (NULL_TREE, handler); /* catch (...) */
4693 :
4694 : /* Get the initial await resume called value. */
4695 1588 : tree not_iarc_if = begin_if_stmt ();
4696 1588 : tree not_iarc = build1_loc (loc, TRUTH_NOT_EXPR,
4697 : boolean_type_node, i_a_r_c);
4698 1588 : finish_if_stmt_cond (not_iarc, not_iarc_if);
4699 : /* If the initial await resume called value is false, rethrow... */
4700 1588 : tree rethrow = build_throw (loc, NULL_TREE, tf_warning_or_error);
4701 1588 : suppress_warning (rethrow);
4702 1588 : finish_expr_stmt (rethrow);
4703 1588 : finish_then_clause (not_iarc_if);
4704 1588 : finish_if_stmt (not_iarc_if);
4705 : /* ... else call the promise unhandled exception method
4706 : but first we set done = true and the resume index to 0.
4707 : If the unhandled exception method returns, then we continue
4708 : to the final await expression (which duplicates the clearing of
4709 : the field). */
4710 1588 : tree r = build2_loc (loc, MODIFY_EXPR, act_des_fn_ptr_type, resume_fn_ptr,
4711 : zero_resume);
4712 1588 : finish_expr_stmt (r);
4713 1588 : tree short_zero = build_int_cst (short_unsigned_type_node, 0);
4714 1588 : r = build2 (MODIFY_EXPR, short_unsigned_type_node, resume_idx_var,
4715 : short_zero);
4716 1588 : finish_expr_stmt (r);
4717 1588 : finish_expr_stmt (ueh);
4718 1588 : finish_handler (handler);
4719 1588 : TRY_HANDLERS (tcb) = pop_stmt_list (TRY_HANDLERS (tcb));
4720 : }
4721 : else
4722 : {
4723 22 : if (pedantic)
4724 : {
4725 : /* We still try to look for the promise method and warn if it's not
4726 : present. */
4727 18 : tree ueh_meth
4728 18 : = lookup_promise_method (orig_fn_decl,
4729 : coro_unhandled_exception_identifier,
4730 : loc, /*musthave=*/false);
4731 18 : if (!ueh_meth || ueh_meth == error_mark_node)
4732 6 : warning_at (loc, 0, "no member named %qE in %qT",
4733 : coro_unhandled_exception_identifier,
4734 : get_coroutine_promise_type (orig_fn_decl));
4735 : }
4736 : /* Else we don't check and don't care if the method is missing..
4737 : just add the initial suspend, function and return. */
4738 22 : finish_expr_stmt (initial_await);
4739 : /* Append the original function body. */
4740 22 : add_stmt (coroutine_body);
4741 22 : if (return_void)
4742 19 : add_stmt (return_void);
4743 : }
4744 :
4745 : /* We are now doing actions associated with the end of the function, so
4746 : point to the closing brace. */
4747 1610 : input_location = loc = fn_end;
4748 :
4749 : /* co_return branches to the final_suspend label, so declare that now. */
4750 1610 : fs_label
4751 1610 : = create_named_label_with_ctx (loc, "final.suspend", NULL_TREE);
4752 1610 : add_stmt (build_stmt (loc, LABEL_EXPR, fs_label));
4753 :
4754 : /* Before entering the final suspend point, we signal that this point has
4755 : been reached by setting the resume function pointer to zero (this is
4756 : what the 'done()' builtin tests) as per the current ABI. */
4757 1610 : zero_resume = build2_loc (loc, MODIFY_EXPR, act_des_fn_ptr_type,
4758 : resume_fn_ptr, zero_resume);
4759 1610 : finish_expr_stmt (zero_resume);
4760 1610 : finish_expr_stmt (final_await);
4761 :
4762 1610 : BIND_EXPR_BODY (update_body) = pop_stmt_list (BIND_EXPR_BODY (update_body));
4763 1610 : BIND_EXPR_VARS (update_body) = nreverse (var_list);
4764 1610 : BLOCK_VARS (top_block) = BIND_EXPR_VARS (update_body);
4765 :
4766 1610 : coroutine_body = update_body;
4767 1610 : }
4768 :
4769 : /* Extract the body of the function we are going to outline, leaving
4770 : to original function decl ready to build the ramp. */
4771 :
4772 : static tree
4773 1673 : split_coroutine_body_from_ramp (tree fndecl)
4774 : {
4775 : /* Sanity-check and punt if we have a nonsense tree because of earlier
4776 : parse errors, perhaps. */
4777 1673 : if (!current_binding_level
4778 1673 : || current_binding_level->kind != sk_function_parms)
4779 : return NULL_TREE;
4780 :
4781 : /* Once we've tied off the original user-authored body in fn_body.
4782 : Start the replacement synthesized ramp body. */
4783 :
4784 1673 : tree body;
4785 1673 : if (use_eh_spec_block (fndecl))
4786 : {
4787 363 : body = pop_stmt_list (TREE_OPERAND (current_eh_spec_block, 0));
4788 363 : TREE_OPERAND (current_eh_spec_block, 0) = push_stmt_list ();
4789 : }
4790 : else
4791 : {
4792 1310 : body = pop_stmt_list (DECL_SAVED_TREE (fndecl));
4793 1310 : DECL_SAVED_TREE (fndecl) = push_stmt_list ();
4794 : }
4795 :
4796 : /* We can't validly get here with an empty statement list, since there's no
4797 : way for the FE to decide it's a coroutine in the absence of any code. */
4798 1673 : gcc_checking_assert (body != NULL_TREE);
4799 :
4800 : /* If we have an empty or erroneous function body, do not try to transform it
4801 : since that would potentially wrap errors. */
4802 1673 : tree body_start = expr_first (body);
4803 1673 : if (body_start == NULL_TREE || body_start == error_mark_node)
4804 : {
4805 : /* Restore the original state. */
4806 63 : add_stmt (body);
4807 63 : return NULL_TREE;
4808 : }
4809 : return body;
4810 : }
4811 :
4812 : /* Build the expression to allocate the coroutine frame according to the
4813 : rules of [dcl.fct.def.coroutine] / 9. */
4814 :
4815 : static tree
4816 1607 : build_coroutine_frame_alloc_expr (tree promise_type, tree orig_fn_decl,
4817 : location_t fn_start, tree grooaf,
4818 : hash_map<tree, param_info> *param_uses,
4819 : tree frame_size)
4820 : {
4821 : /* Allocate the frame, this has several possibilities:
4822 : [dcl.fct.def.coroutine] / 9 (part 1)
4823 : The allocation function’s name is looked up in the scope of the promise
4824 : type. It is not a failure for it to be absent see part 4, below. */
4825 :
4826 1607 : tree nwname = ovl_op_identifier (false, NEW_EXPR);
4827 1607 : tree new_fn_call = NULL_TREE;
4828 1607 : tree dummy_promise
4829 1607 : = build_dummy_object (get_coroutine_promise_type (orig_fn_decl));
4830 :
4831 1607 : if (TYPE_HAS_NEW_OPERATOR (promise_type))
4832 : {
4833 184 : tree fns = lookup_promise_method (orig_fn_decl, nwname, fn_start,
4834 : /*musthave=*/true);
4835 : /* [dcl.fct.def.coroutine] / 9 (part 2)
4836 : If the lookup finds an allocation function in the scope of the promise
4837 : type, overload resolution is performed on a function call created by
4838 : assembling an argument list. The first argument is the amount of space
4839 : requested, and has type std::size_t. The lvalues p1...pn are the
4840 : succeeding arguments.. */
4841 184 : vec<tree, va_gc> *args = make_tree_vector ();
4842 184 : vec_safe_push (args, frame_size); /* Space needed. */
4843 :
4844 329 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
4845 145 : arg = DECL_CHAIN (arg))
4846 : {
4847 145 : param_info *parm_i = param_uses->get (arg);
4848 145 : gcc_checking_assert (parm_i);
4849 145 : if (parm_i->this_ptr || parm_i->lambda_cobj)
4850 : {
4851 : /* We pass a reference to *this to the allocator lookup. */
4852 : /* It's unsafe to use the cp_ version here since current_class_ref
4853 : might've gotten clobbered earlier during rewrite_param_uses. */
4854 4 : tree this_ref = build_fold_indirect_ref (arg);
4855 4 : vec_safe_push (args, this_ref);
4856 4 : }
4857 : else
4858 141 : vec_safe_push (args, convert_from_reference (arg));
4859 : }
4860 :
4861 : /* Note the function selected; we test to see if it's NOTHROW. */
4862 184 : tree func;
4863 : /* Failure is not an error for this attempt. */
4864 184 : new_fn_call = build_new_method_call (dummy_promise, fns, &args, NULL,
4865 : LOOKUP_NORMAL, &func, tf_none);
4866 184 : release_tree_vector (args);
4867 :
4868 184 : if (new_fn_call == error_mark_node)
4869 : {
4870 : /* [dcl.fct.def.coroutine] / 9 (part 3)
4871 : If no viable function is found, overload resolution is performed
4872 : again on a function call created by passing just the amount of
4873 : space required as an argument of type std::size_t. */
4874 82 : args = make_tree_vector_single (frame_size); /* Space needed. */
4875 82 : new_fn_call = build_new_method_call (dummy_promise, fns, &args,
4876 : NULL_TREE, LOOKUP_NORMAL, &func,
4877 : tf_none);
4878 82 : release_tree_vector (args);
4879 : }
4880 :
4881 : /* However, if the promise provides an operator new, then one of these
4882 : two options must be available. */
4883 184 : if (new_fn_call == error_mark_node)
4884 : {
4885 3 : error_at (fn_start, "%qE is provided by %qT but is not usable with"
4886 : " the function signature %qD", nwname, promise_type,
4887 : orig_fn_decl);
4888 6 : return error_mark_node;
4889 : }
4890 181 : else if (grooaf && !TYPE_NOTHROW_P (TREE_TYPE (func)))
4891 : {
4892 3 : error_at (fn_start, "%qE is provided by %qT but %qE is not marked"
4893 : " %<throw()%> or %<noexcept%>", grooaf, promise_type, nwname);
4894 3 : return error_mark_node;
4895 : }
4896 178 : else if (!grooaf && TYPE_NOTHROW_P (TREE_TYPE (func)))
4897 3 : warning_at (fn_start, 0, "%qE is marked %<throw()%> or %<noexcept%> but"
4898 : " no usable %<get_return_object_on_allocation_failure%>"
4899 : " is provided by %qT", nwname, promise_type);
4900 : }
4901 : else /* No operator new in the promise. */
4902 : {
4903 : /* [dcl.fct.def.coroutine] / 9 (part 4)
4904 : If this lookup fails, the allocation function’s name is looked up in
4905 : the global scope. */
4906 :
4907 1423 : vec<tree, va_gc> *args;
4908 : /* build_operator_new_call () will insert size needed as element 0 of
4909 : this, and we might need to append the std::nothrow constant. */
4910 1423 : vec_alloc (args, 2);
4911 1423 : if (grooaf)
4912 : {
4913 : /* [dcl.fct.def.coroutine] / 10 (part 2)
4914 : If any declarations (of the get return on allocation fail) are
4915 : found, then the result of a call to an allocation function used
4916 : to obtain storage for the coroutine state is assumed to return
4917 : nullptr if it fails to obtain storage and, if a global allocation
4918 : function is selected, the ::operator new(size_t, nothrow_t) form
4919 : is used. The allocation function used in this case shall have a
4920 : non-throwing noexcept-specification. So we need std::nothrow. */
4921 13 : tree std_nt = lookup_qualified_name (std_node,
4922 : get_identifier ("nothrow"),
4923 : LOOK_want::NORMAL,
4924 13 : /*complain=*/true);
4925 13 : if (!std_nt || std_nt == error_mark_node)
4926 : {
4927 : /* Something is seriously wrong, punt. */
4928 3 : error_at (fn_start, "%qE is provided by %qT but %<std::nothrow%>"
4929 : " cannot be found", grooaf, promise_type);
4930 3 : return error_mark_node;
4931 : }
4932 10 : vec_safe_push (args, std_nt);
4933 : }
4934 :
4935 : /* If we get to this point, we must succeed in looking up the global
4936 : operator new for the params provided. Since we are not setting
4937 : size_check or cookie, we expect frame_size to be unaltered. */
4938 1420 : tree cookie = NULL;
4939 1420 : new_fn_call = build_operator_new_call (nwname, &args, &frame_size,
4940 : &cookie, /*align_arg=*/NULL,
4941 : /*size_check=*/NULL, /*fn=*/NULL,
4942 : tf_warning_or_error);
4943 1420 : release_tree_vector (args);
4944 : }
4945 : return new_fn_call;
4946 : }
4947 :
4948 : /* Build an expression to delete the coroutine state frame. */
4949 :
4950 : static tree
4951 3187 : build_coroutine_frame_delete_expr (tree coro_fp, tree frame_size,
4952 : tree promise_type, location_t loc)
4953 : {
4954 : /* Cast the frame pointer to a pointer to promise so that the build op
4955 : delete call will search the promise. */
4956 3187 : tree pptr_type = build_pointer_type (promise_type);
4957 3187 : tree frame_arg = build1_loc (loc, CONVERT_EXPR, pptr_type, coro_fp);
4958 : /* [dcl.fct.def.coroutine] / 12 sentence 3:
4959 : If both a usual deallocation function with only a pointer parameter and
4960 : a usual deallocation function with both a pointer parameter and a size
4961 : parameter are found, then the selected deallocation function shall be the
4962 : one with two parameters. */
4963 3187 : tree del_coro_fr
4964 3187 : = build_coroutine_op_delete_call (DELETE_EXPR, frame_arg, frame_size,
4965 : /*global_p=*/false, /*placement=*/NULL,
4966 : /*alloc_fn=*/NULL, tf_warning_or_error);
4967 3187 : if (!del_coro_fr || del_coro_fr == error_mark_node)
4968 3 : return error_mark_node;
4969 : return del_coro_fr;
4970 : }
4971 :
4972 : /* Build the ramp function.
4973 : Here we take the original function definition which has now had its body
4974 : removed, and use it as the declaration of the ramp which both replaces the
4975 : user's written function at call sites, and is responsible for starting
4976 : the coroutine it defined.
4977 : returns false on error.
4978 :
4979 : We should arrive here with the state of the compiler as if we had just
4980 : executed start_preparsed_function(). */
4981 :
4982 : bool
4983 1610 : cp_coroutine_transform::build_ramp_function ()
4984 : {
4985 1610 : gcc_checking_assert (current_binding_level
4986 : && current_binding_level->kind == sk_function_parms);
4987 :
4988 : /* This is completely synthetic code, if we find an issue then we have not
4989 : much chance to point at the most useful place in the user's code. In
4990 : lieu of this use the function start - so at least the diagnostic relates
4991 : to something that the user can inspect. */
4992 1610 : iloc_sentinel saved_position (fn_start);
4993 1610 : location_t loc = fn_start;
4994 :
4995 1610 : tree promise_type = get_coroutine_promise_type (orig_fn_decl);
4996 1610 : tree fn_return_type = TREE_TYPE (TREE_TYPE (orig_fn_decl));
4997 1610 : bool void_ramp_p = VOID_TYPE_P (fn_return_type);
4998 : /* We know there was no return statement, that is intentional. */
4999 1610 : suppress_warning (orig_fn_decl, OPT_Wreturn_type);
5000 :
5001 : /* [dcl.fct.def.coroutine] / 10 (part1)
5002 : The unqualified-id get_return_object_on_allocation_failure is looked up
5003 : in the scope of the promise type by class member access lookup. */
5004 :
5005 : /* We don't require this, but, if the lookup succeeds, then the function
5006 : must be usable, punt if it is not. */
5007 1610 : tree grooaf_meth
5008 1610 : = lookup_promise_method (orig_fn_decl,
5009 : coro_gro_on_allocation_fail_identifier, loc,
5010 : /*musthave*/ false);
5011 1610 : tree grooaf = NULL_TREE;
5012 1610 : tree dummy_promise
5013 3220 : = build_dummy_object (get_coroutine_promise_type (orig_fn_decl));
5014 1610 : if (grooaf_meth && grooaf_meth != error_mark_node)
5015 : {
5016 47 : grooaf
5017 47 : = coro_build_promise_expression (orig_fn_decl, dummy_promise,
5018 : coro_gro_on_allocation_fail_identifier,
5019 : fn_start, NULL, /*musthave=*/false);
5020 :
5021 : /* That should succeed. */
5022 47 : if (!grooaf || grooaf == error_mark_node)
5023 : {
5024 3 : error_at (fn_start, "%qE is provided by %qT but is not usable with"
5025 : " the function %qD", coro_gro_on_allocation_fail_identifier,
5026 : promise_type, orig_fn_decl);
5027 3 : return false;
5028 : }
5029 : }
5030 :
5031 : /* Check early for usable allocator/deallocator, without which we cannot
5032 : build a useful ramp; early exit if they are not available or usable. */
5033 :
5034 1607 : frame_size = TYPE_SIZE_UNIT (frame_type);
5035 :
5036 : /* Make a var to represent the frame pointer early. */
5037 1607 : tree coro_fp = coro_build_artificial_var (loc, "_Coro_frameptr",
5038 : frame_ptr_type, orig_fn_decl,
5039 : NULL_TREE);
5040 :
5041 1607 : tree new_fn_call
5042 1607 : = build_coroutine_frame_alloc_expr (promise_type, orig_fn_decl, fn_start,
5043 : grooaf, ¶m_uses, frame_size);
5044 :
5045 : /* We must have a useable allocator to proceed. */
5046 1607 : if (!new_fn_call || new_fn_call == error_mark_node)
5047 : return false;
5048 :
5049 : /* Likewise, we need the DTOR to delete the frame. */
5050 1598 : tree delete_frame_call
5051 1598 : = build_coroutine_frame_delete_expr (coro_fp, frame_size, promise_type,
5052 : fn_start);
5053 1598 : if (!delete_frame_call || delete_frame_call == error_mark_node)
5054 : return false;
5055 :
5056 : /* At least verify we can lookup the get return object method. */
5057 1595 : tree get_ro_meth
5058 1595 : = lookup_promise_method (orig_fn_decl,
5059 : coro_get_return_object_identifier, loc,
5060 : /*musthave*/ true);
5061 1595 : if (!get_ro_meth || get_ro_meth == error_mark_node)
5062 : return false;
5063 :
5064 : /* So now construct the Ramp: */
5065 :
5066 1592 : tree ramp_fnbody = begin_compound_stmt (BCS_FN_BODY);
5067 1592 : coro_fp = pushdecl (coro_fp);
5068 1592 : add_decl_expr (coro_fp);
5069 :
5070 : /* Build the frame. */
5071 :
5072 : /* The CO_FRAME internal function is a mechanism to allow the middle end
5073 : to adjust the allocation in response to optimizations. We provide the
5074 : current conservative estimate of the frame size (as per the current)
5075 : computed layout. */
5076 :
5077 1592 : tree resizeable
5078 1592 : = build_call_expr_internal_loc (loc, IFN_CO_FRAME, size_type_node, 2,
5079 : frame_size,
5080 : build_zero_cst (frame_ptr_type));
5081 1592 : CALL_EXPR_ARG (new_fn_call, 0) = resizeable;
5082 1592 : tree allocated = build1 (CONVERT_EXPR, frame_ptr_type, new_fn_call);
5083 1592 : tree r = cp_build_init_expr (coro_fp, allocated);
5084 1592 : finish_expr_stmt (r);
5085 :
5086 : /* If the user provided a method to return an object on alloc fail, then
5087 : check the returned pointer and call the func if it's null.
5088 : Otherwise, no check, and we fail for noexcept/fno-exceptions cases. */
5089 :
5090 1592 : tree grooaf_if_stmt = NULL_TREE;
5091 1592 : tree alloc_ok_scope = NULL_TREE;
5092 1592 : if (grooaf)
5093 : {
5094 : /* [dcl.fct.def.coroutine] / 10 (part 3)
5095 : If the allocation function returns nullptr,the coroutine returns
5096 : control to the caller of the coroutine and the return value is
5097 : obtained by a call to T::get_return_object_on_allocation_failure(),
5098 : where T is the promise type. */
5099 38 : tree cond = build1 (CONVERT_EXPR, frame_ptr_type, nullptr_node);
5100 38 : cond = build2 (NE_EXPR, boolean_type_node, coro_fp, cond);
5101 38 : grooaf_if_stmt = begin_if_stmt ();
5102 38 : finish_if_stmt_cond (cond, grooaf_if_stmt);
5103 38 : alloc_ok_scope = begin_compound_stmt (BCS_NORMAL);
5104 : }
5105 :
5106 : /* Dereference the frame pointer, to use in member access code. */
5107 1592 : tree deref_fp
5108 1592 : = cp_build_indirect_ref (loc, coro_fp, RO_UNARY_STAR, tf_warning_or_error);
5109 :
5110 : /* For now, once allocation has succeeded we always assume that this needs
5111 : destruction, there's no impl. for frame allocation elision. */
5112 1592 : tree frame_needs_free
5113 1592 : = coro_build_and_push_artificial_var_with_dve (loc,
5114 : coro_frame_needs_free_id,
5115 : boolean_type_node,
5116 : orig_fn_decl,
5117 : boolean_true_node,
5118 : deref_fp);
5119 : /* Although it appears to be unused here the frame entry is needed and we
5120 : just set it true. */
5121 1592 : TREE_USED (frame_needs_free) = true;
5122 :
5123 1592 : tree coro_frame_refcount
5124 1592 : = coro_build_and_push_artificial_var_with_dve (loc, coro_frame_refcount_id,
5125 : short_unsigned_type_node,
5126 : orig_fn_decl, NULL_TREE,
5127 : deref_fp);
5128 : /* Cleanup if both the ramp and the body have finished. */
5129 1592 : tree cond
5130 1592 : = build2_loc (loc, EQ_EXPR, short_unsigned_type_node, coro_frame_refcount,
5131 : build_int_cst (short_unsigned_type_node, 0));
5132 1592 : r = build3 (COND_EXPR, void_type_node, cond, delete_frame_call,
5133 : build_empty_stmt (loc));
5134 1592 : push_cleanup (coro_fp, r, /*eh_only*/false);
5135 :
5136 : /* Put the resumer and destroyer functions in. */
5137 :
5138 1592 : tree actor_addr = build1 (ADDR_EXPR, act_des_fn_ptr_type, resumer);
5139 1592 : coro_build_and_push_artificial_var_with_dve (loc, coro_resume_fn_id,
5140 : act_des_fn_ptr_type,
5141 : orig_fn_decl,
5142 : actor_addr, deref_fp);
5143 :
5144 1592 : tree destroy_addr = build1 (ADDR_EXPR, act_des_fn_ptr_type, destroyer);
5145 1592 : coro_build_and_push_artificial_var_with_dve (loc, coro_destroy_fn_id,
5146 : act_des_fn_ptr_type,
5147 : orig_fn_decl,
5148 : destroy_addr, deref_fp);
5149 :
5150 : /* [dcl.fct.def.coroutine] /13
5151 : When a coroutine is invoked, a copy is created for each coroutine
5152 : parameter. Each such copy is an object with automatic storage duration
5153 : that is direct-initialized from an lvalue referring to the corresponding
5154 : parameter if the parameter is an lvalue reference, and from an xvalue
5155 : referring to it otherwise. A reference to a parameter in the function-
5156 : body of the coroutine and in the call to the coroutine promise
5157 : constructor is replaced by a reference to its copy. */
5158 :
5159 1592 : vec<tree, va_gc> *promise_args = NULL; /* So that we can adjust refs. */
5160 :
5161 : /* The initialization and destruction of each parameter copy occurs in the
5162 : context of the called coroutine. Initializations of parameter copies are
5163 : sequenced before the call to the coroutine promise constructor and
5164 : indeterminately sequenced with respect to each other. The lifetime of
5165 : parameter copies ends immediately after the lifetime of the coroutine
5166 : promise object ends. */
5167 :
5168 1592 : if (DECL_ARGUMENTS (orig_fn_decl))
5169 : {
5170 775 : promise_args = make_tree_vector ();
5171 1775 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
5172 1000 : arg = DECL_CHAIN (arg))
5173 : {
5174 1000 : bool existed;
5175 1000 : param_info &parm = param_uses.get_or_insert (arg, &existed);
5176 1000 : tree fld_idx
5177 1000 : = coro_build_frame_access_expr (deref_fp, parm.field_id,
5178 1000 : false, tf_warning_or_error);
5179 :
5180 : /* Add this to the promise CTOR arguments list, accounting for
5181 : refs and special handling for method this ptr. */
5182 1000 : if (parm.this_ptr || parm.lambda_cobj)
5183 : {
5184 : /* We pass a reference to *this to the param preview. */
5185 : /* It's unsafe to use the cp_ version here since current_class_ref
5186 : might've gotten clobbered earlier during rewrite_param_uses. */
5187 253 : tree this_ref = build_fold_indirect_ref (arg);
5188 253 : vec_safe_push (promise_args, this_ref);
5189 253 : }
5190 747 : else if (parm.rv_ref)
5191 41 : vec_safe_push (promise_args, move (fld_idx));
5192 : else
5193 706 : vec_safe_push (promise_args, fld_idx);
5194 :
5195 1000 : if (parm.rv_ref || parm.pt_ref)
5196 : /* Initialise the frame reference field directly. */
5197 131 : r = build2 (INIT_EXPR, TREE_TYPE (arg),
5198 131 : TREE_OPERAND (fld_idx, 0), arg);
5199 : else
5200 : {
5201 869 : r = forward_parm (arg);
5202 869 : r = cp_build_modify_expr (loc, fld_idx, INIT_EXPR, r,
5203 : tf_warning_or_error);
5204 : }
5205 1000 : finish_expr_stmt (r);
5206 :
5207 : /* Arrange for parm copies to be cleaned up when an exception is
5208 : thrown before initial await resume. */
5209 1000 : if (!parm.trivial_dtor)
5210 : {
5211 115 : parm.fr_copy_dtor
5212 115 : = cxx_maybe_build_cleanup (fld_idx, tf_warning_or_error);
5213 115 : if (parm.fr_copy_dtor && parm.fr_copy_dtor != error_mark_node)
5214 : {
5215 115 : param_dtor_list.safe_push (parm.field_id);
5216 115 : cond
5217 115 : = build2_loc (loc, EQ_EXPR, short_unsigned_type_node,
5218 : coro_frame_refcount,
5219 : build_int_cst (short_unsigned_type_node, 0));
5220 115 : r = build3_loc (loc, COND_EXPR, void_type_node, cond,
5221 : parm.fr_copy_dtor, build_empty_stmt (loc));
5222 115 : push_cleanup (fld_idx, r, /*eh_only*/false);
5223 : }
5224 : }
5225 : }
5226 : }
5227 :
5228 : /* Set up the promise. */
5229 1592 : tree p
5230 1592 : = coro_build_and_push_artificial_var_with_dve (loc, coro_promise_id,
5231 : promise_type, orig_fn_decl,
5232 : NULL_TREE, deref_fp);
5233 :
5234 1592 : if (type_build_ctor_call (promise_type))
5235 : {
5236 : /* Construct the promise object [dcl.fct.def.coroutine] / 5.7.
5237 :
5238 : First try to find a constructor with an argument list comprised of
5239 : the parameter copies. */
5240 :
5241 1047 : if (DECL_ARGUMENTS (orig_fn_decl))
5242 : {
5243 615 : r = build_special_member_call (p, complete_ctor_identifier,
5244 : &promise_args, promise_type,
5245 : LOOKUP_NORMAL, tf_none);
5246 615 : release_tree_vector (promise_args);
5247 : }
5248 : else
5249 : r = NULL_TREE;
5250 :
5251 : /* If that fails then the promise constructor argument list is empty. */
5252 615 : if (r == NULL_TREE || r == error_mark_node)
5253 777 : r = build_special_member_call (p, complete_ctor_identifier, NULL,
5254 : promise_type, LOOKUP_NORMAL,
5255 : tf_warning_or_error);
5256 :
5257 : /* If type_build_ctor_call() encounters deprecated implicit CTORs it will
5258 : return true, and therefore we will execute this code path. However,
5259 : we might well not actually require a CTOR and under those conditions
5260 : the build call above will not return a call expression, but the
5261 : original instance object. Do not attempt to add the statement unless
5262 : it has side-effects. */
5263 1047 : if (r && r != error_mark_node && TREE_SIDE_EFFECTS (r))
5264 1009 : finish_expr_stmt (r);
5265 : }
5266 :
5267 1592 : tree promise_dtor = cxx_maybe_build_cleanup (p, tf_warning_or_error);
5268 : /* If the promise is live, then run its dtor if that's available. */
5269 1592 : if (promise_dtor && promise_dtor != error_mark_node)
5270 : {
5271 954 : cond = build2_loc (loc, EQ_EXPR, short_unsigned_type_node,
5272 : coro_frame_refcount,
5273 : build_int_cst (short_unsigned_type_node, 0));
5274 954 : r = build3 (COND_EXPR, void_type_node, cond, promise_dtor,
5275 : build_empty_stmt (loc));
5276 954 : push_cleanup (p, r, /*eh_only*/false);
5277 : }
5278 :
5279 1592 : tree get_ro
5280 1592 : = coro_build_promise_expression (orig_fn_decl, p,
5281 : coro_get_return_object_identifier,
5282 : fn_start, NULL, /*musthave=*/true);
5283 :
5284 : /* Without a return object we haven't got much clue what's going on. */
5285 1592 : if (!get_ro || get_ro == error_mark_node)
5286 : return false;
5287 :
5288 : /* Check for a bad get return object type.
5289 : [dcl.fct.def.coroutine] / 7 requires:
5290 : The expression promise.get_return_object() is used to initialize the
5291 : returned reference or prvalue result object ...
5292 : When we use a local to hold this, it is decltype(auto). */
5293 1592 : tree gro_type
5294 1592 : = finish_decltype_type (get_ro, /*id_expression_or_member_access_p*/false,
5295 : tf_warning_or_error);
5296 1592 : if (VOID_TYPE_P (gro_type) && !void_ramp_p)
5297 : {
5298 3 : error_at (fn_start, "no viable conversion from %<void%> provided by"
5299 : " %<get_return_object%> to return type %qT", fn_return_type);
5300 3 : return false;
5301 : }
5302 :
5303 : /* Initialize the resume_idx_var to 0, meaning "not started". */
5304 1589 : coro_build_and_push_artificial_var_with_dve
5305 1589 : (loc, coro_resume_index_id, short_unsigned_type_node, orig_fn_decl,
5306 : build_zero_cst (short_unsigned_type_node), deref_fp);
5307 :
5308 : /* We must manage the cleanups ourselves, with the exception of the g_r_o,
5309 : because the responsibility for them changes after the initial suspend.
5310 : However, any use of cxx_maybe_build_cleanup () in preceding code can
5311 : set the throwing_cleanup flag. */
5312 1589 : cp_function_chain->throwing_cleanup = false;
5313 :
5314 : /* [dcl.fct.def.coroutine] / 7
5315 : The expression promise.get_return_object() is used to initialize the
5316 : glvalue result or prvalue result object of a call to a coroutine. */
5317 :
5318 1589 : tree coro_gro = NULL_TREE;
5319 1589 : if (void_ramp_p)
5320 : /* We still want to call the method, even if the result is unused. */
5321 14 : finish_expr_stmt (get_ro);
5322 : else
5323 : {
5324 : /* Per CWG2563, we keep the result of promise.get_return_object () in
5325 : a temp which is then used to intialize the return object, including
5326 : NVRO. */
5327 :
5328 1575 : coro_gro
5329 1575 : = coro_build_and_push_artificial_var (loc, "_Coro_gro", gro_type,
5330 : orig_fn_decl, NULL_TREE);
5331 :
5332 1575 : r = cp_build_init_expr (coro_gro, STRIP_REFERENCE_REF (get_ro));
5333 1575 : finish_expr_stmt (r);
5334 1575 : tree coro_gro_cleanup
5335 1575 : = cxx_maybe_build_cleanup (coro_gro, tf_warning_or_error);
5336 1575 : if (coro_gro_cleanup)
5337 259 : push_cleanup (coro_gro, coro_gro_cleanup, /*eh_only*/false);
5338 : }
5339 :
5340 : /* Start the coroutine body, we now have a use of the frame... */
5341 1589 : r = cp_build_modify_expr (loc, coro_frame_refcount, NOP_EXPR,
5342 : build_int_cst (short_unsigned_type_node, 1),
5343 : tf_warning_or_error);
5344 1589 : finish_expr_stmt (r);
5345 : /* ... but when we finish we want to release that, and we want to do that
5346 : before any of the other cleanups run. */
5347 1589 : tree released
5348 1589 : = build2_loc (loc, MINUS_EXPR, short_unsigned_type_node, coro_frame_refcount,
5349 : build_int_cst (short_unsigned_type_node, 1));
5350 1589 : released = cp_build_modify_expr (loc, coro_frame_refcount, NOP_EXPR, released,
5351 : tf_warning_or_error);
5352 1589 : push_cleanup (NULL_TREE, released, /*eh_only*/false);
5353 :
5354 1589 : r = build_call_expr_loc (fn_start, resumer, 1, coro_fp);
5355 1589 : finish_expr_stmt (r);
5356 :
5357 : /* The ramp is done, we just need the return statement, which we build from
5358 : the return object we constructed before we called the actor. */
5359 :
5360 : /* This is our 'normal' exit. */
5361 1589 : r = void_ramp_p ? NULL_TREE : convert_from_reference (coro_gro);
5362 1589 : finish_return_stmt (r);
5363 :
5364 1589 : if (grooaf)
5365 : {
5366 38 : finish_compound_stmt (alloc_ok_scope);
5367 38 : finish_then_clause (grooaf_if_stmt);
5368 :
5369 38 : begin_else_clause (grooaf_if_stmt);
5370 : /* We come here if the frame allocation failed. */
5371 38 : r = NULL_TREE;
5372 38 : if (void_ramp_p)
5373 : /* Execute the get-return-object-on-alloc-fail call... */
5374 0 : finish_expr_stmt (grooaf);
5375 : else
5376 : /* Get the fallback return object. */
5377 : r = grooaf;
5378 38 : finish_return_stmt (r);
5379 38 : finish_if_stmt (grooaf_if_stmt);
5380 : }
5381 :
5382 1589 : finish_compound_stmt (ramp_fnbody);
5383 1589 : return true;
5384 1610 : }
5385 :
5386 : /* ------- Encapsulate analysis of the couroutine -------- */
5387 :
5388 :
5389 1673 : cp_coroutine_transform::cp_coroutine_transform (tree _orig_fn, bool _inl)
5390 1673 : : orig_fn_decl (_orig_fn), inline_p (_inl)
5391 : {
5392 : /* We don't expect to be called with missing decl or e_m_n. */
5393 1673 : gcc_checking_assert (orig_fn_decl
5394 : && TREE_CODE (orig_fn_decl) == FUNCTION_DECL);
5395 1673 : if (!coro_function_valid_p (orig_fn_decl))
5396 : {
5397 : /* For early errors, we do not want a diagnostic about the missing
5398 : ramp return value, since the user cannot fix this - a 'return' is
5399 : not allowed in a coroutine. */
5400 60 : suppress_warning (orig_fn_decl, OPT_Wreturn_type);
5401 : /* Discard the body, we can't process it further... */
5402 60 : pop_stmt_list (DECL_SAVED_TREE (orig_fn_decl));
5403 : /* ... and make an empty fn. */
5404 60 : DECL_SAVED_TREE (orig_fn_decl) = push_stmt_list ();
5405 : /* Match the expected nesting when an eh block is in use. */
5406 60 : if (use_eh_spec_block (orig_fn_decl))
5407 0 : current_eh_spec_block = begin_eh_spec_block ();
5408 60 : valid_coroutine = false;
5409 : }
5410 :
5411 : /* We don't have the locus of the opening brace - it's filled in later (and
5412 : there doesn't really seem to be any easy way to get at it). */
5413 1673 : fn_start = DECL_SOURCE_LOCATION (orig_fn_decl);
5414 : /* The closing brace is assumed to be input_location. */
5415 1673 : fn_end = input_location;
5416 :
5417 : /* Build types we need. */
5418 1673 : tree fr_name = get_fn_local_identifier (orig_fn_decl, "Frame");
5419 1673 : frame_type = xref_tag (record_type, fr_name);
5420 1673 : DECL_CONTEXT (TYPE_NAME (frame_type)) = DECL_CONTEXT (orig_fn_decl);
5421 1673 : frame_ptr_type = build_pointer_type (frame_type);
5422 1673 : act_des_fn_type
5423 1673 : = build_function_type_list (void_type_node, frame_ptr_type, NULL_TREE);
5424 1673 : act_des_fn_ptr_type = build_pointer_type (act_des_fn_type);
5425 1673 : valid_coroutine = true;
5426 1673 : }
5427 :
5428 1673 : cp_coroutine_transform::~cp_coroutine_transform ()
5429 : {
5430 1673 : }
5431 :
5432 : /* Here we:
5433 : a) Check that the function and promise type are valid for a
5434 : coroutine.
5435 : b) Carry out the initial morph to create the skeleton of the
5436 : coroutine ramp function and the rewritten body.
5437 :
5438 : Assumptions.
5439 :
5440 : 1. We only hit this code once all dependencies are resolved.
5441 : 2. The function body will be either a bind expr or a statement list
5442 : 3. That cfun and current_function_decl are valid for the case we're
5443 : expanding.
5444 : 4. 'input_location' will be of the final brace for the function.
5445 :
5446 : We do something like this:
5447 : declare a dummy coro frame.
5448 : struct _R_frame {
5449 : using handle_type = coro::coroutine_handle<coro1::promise_type>;
5450 : void (*_Coro_resume_fn)(_R_frame *);
5451 : void (*_Coro_destroy_fn)(_R_frame *);
5452 : coro1::promise_type _Coro_promise;
5453 : bool _Coro_frame_needs_free; free the coro frame mem if set.
5454 : bool _Coro_i_a_r_c; [dcl.fct.def.coroutine] / 5.3
5455 : short _Coro_resume_index;
5456 : parameter copies (were required).
5457 : local variables saved (including awaitables)
5458 : (maybe) trailing space.
5459 : }; */
5460 :
5461 : void
5462 1673 : cp_coroutine_transform::apply_transforms ()
5463 : {
5464 1673 : if (dmp_str == NULL)
5465 1673 : dmp_str = dump_begin (coro_dump_id, &coro_dump_flags);
5466 :
5467 1673 : coro_maybe_dump_initial_function (orig_fn_decl);
5468 :
5469 1673 : coroutine_body
5470 1673 : = split_coroutine_body_from_ramp (orig_fn_decl);
5471 1673 : if (!coroutine_body)
5472 : {
5473 63 : valid_coroutine = false;
5474 63 : return;
5475 : }
5476 : /* Keep the original function block tree to one side and reset. */
5477 1610 : body_blocks = current_binding_level->blocks;
5478 1610 : current_binding_level->blocks = NULL_TREE;
5479 :
5480 : /* Collect information on the original function params and their use in the
5481 : function body. */
5482 1610 : analyze_fn_parms ();
5483 :
5484 : /* Declare the actor and destroyer functions, the following code needs to
5485 : see these. */
5486 1610 : resumer
5487 1610 : = coro_build_actor_or_destroy_function (orig_fn_decl, act_des_fn_type,
5488 : frame_ptr_type, true);
5489 1610 : destroyer
5490 1610 : = coro_build_actor_or_destroy_function (orig_fn_decl, act_des_fn_type,
5491 : frame_ptr_type, false);
5492 :
5493 : /* Avoid repeating diagnostics about promise or awaiter fails. */
5494 1610 : if (!seen_error ())
5495 : {
5496 1580 : iloc_sentinel stable_input_loc (fn_start);
5497 1580 : initial_await = build_init_or_final_await (fn_start, false);
5498 1580 : input_location = fn_end;
5499 1580 : if (initial_await && initial_await != error_mark_node)
5500 1574 : final_await = build_init_or_final_await (fn_end, true);
5501 1580 : }
5502 :
5503 : /* Transform the function body as per [dcl.fct.def.coroutine] / 5. */
5504 1610 : wrap_original_function_body ();
5505 :
5506 : /* Analyze the body await expressions. */
5507 1610 : susp_frame_data body_aw_points (fs_label, &suspend_points);
5508 1610 : cp_walk_tree (&coroutine_body, await_statement_walker, &body_aw_points, NULL);
5509 1610 : await_count = body_aw_points.await_number;
5510 :
5511 : /* Determine the fields for the coroutine state. */
5512 1610 : tree field_list = NULL_TREE;
5513 1610 : local_vars_frame_data local_vars_data (&field_list, &local_var_uses);
5514 1610 : cp_walk_tree_without_duplicates (&coroutine_body, register_local_var_uses,
5515 : &local_vars_data);
5516 :
5517 : /* Conservative computation of the coroutine frame content. */
5518 1610 : frame_type = begin_class_definition (frame_type);
5519 1610 : TYPE_FIELDS (frame_type) = field_list;
5520 1610 : TYPE_BINFO (frame_type) = make_tree_binfo (0);
5521 1610 : BINFO_OFFSET (TYPE_BINFO (frame_type)) = size_zero_node;
5522 1610 : BINFO_TYPE (TYPE_BINFO (frame_type)) = frame_type;
5523 1610 : frame_type = finish_struct (frame_type, NULL_TREE);
5524 :
5525 1610 : valid_coroutine = build_ramp_function ();
5526 1610 : coro_maybe_dump_ramp (orig_fn_decl);
5527 : }
5528 :
5529 : /* Having analysed and collected the necessary data we are now in a position
5530 : to build the outlined coroutine body and the destroyer shim. */
5531 :
5532 : void
5533 1589 : cp_coroutine_transform::finish_transforms ()
5534 : {
5535 1589 : if (!valid_coroutine)
5536 : return;
5537 :
5538 1589 : current_function_decl = resumer;
5539 1589 : build_actor_fn (fn_start, frame_type, resumer, coroutine_body, orig_fn_decl,
5540 : &local_var_uses, &suspend_points, ¶m_dtor_list,
5541 1589 : resume_idx_var, await_count, frame_size, inline_p);
5542 :
5543 1589 : current_function_decl = destroyer;
5544 1589 : build_destroy_fn (fn_start, frame_type, destroyer, resumer, inline_p);
5545 :
5546 1589 : coro_maybe_dump_transformed_functions (resumer, destroyer);
5547 : }
5548 :
5549 : #include "gt-cp-coroutines.h"
5550 :
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