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1 : : /* coroutine-specific state, expansions and tests.
2 : :
3 : : Copyright (C) 2018-2025 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 : 1595 : coro_maybe_dump_initial_function (tree fndecl)
81 : : {
82 : 1595 : if (!dmp_str)
83 : 1595 : 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 : 1532 : coro_maybe_dump_ramp (tree ramp)
101 : : {
102 : 1532 : if (!dmp_str)
103 : 1532 : 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 : 1511 : coro_maybe_dump_transformed_functions (tree actor, tree destroy)
120 : : {
121 : 1511 : if (!dmp_str)
122 : 1511 : 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 : : /* The state that we collect during parsing (and template expansion) for
198 : : a coroutine. */
199 : :
200 : 3116 : struct GTY((for_user)) coroutine_info
201 : : {
202 : : tree function_decl; /* The original function decl. */
203 : : tree actor_decl; /* The synthesized actor function. */
204 : : tree destroy_decl; /* The synthesized destroy function. */
205 : : tree promise_type; /* The cached promise type for this function. */
206 : : tree traits_type; /* The cached traits type for this function. */
207 : : tree handle_type; /* The cached coroutine handle for this function. */
208 : : tree self_h_proxy; /* A handle instance that is used as the proxy for the
209 : : one that will eventually be allocated in the coroutine
210 : : frame. */
211 : : tree promise_proxy; /* Likewise, a proxy promise instance. */
212 : : tree from_address; /* handle_type from_address function. */
213 : : tree return_void; /* The expression for p.return_void() if it exists. */
214 : : location_t first_coro_keyword; /* The location of the keyword that made this
215 : : function into a coroutine. */
216 : :
217 : : /* Temporary variable number assigned by get_awaitable_var. */
218 : : int awaitable_number = 0;
219 : :
220 : : /* Flags to avoid repeated errors for per-function issues. */
221 : : bool coro_ret_type_error_emitted;
222 : : bool coro_promise_error_emitted;
223 : : bool coro_co_return_error_emitted;
224 : : };
225 : :
226 : : struct coroutine_info_hasher : ggc_ptr_hash<coroutine_info>
227 : : {
228 : : typedef tree compare_type; /* We only compare the function decl. */
229 : : static inline hashval_t hash (coroutine_info *);
230 : : static inline hashval_t hash (const compare_type &);
231 : : static inline bool equal (coroutine_info *, coroutine_info *);
232 : : static inline bool equal (coroutine_info *, const compare_type &);
233 : : };
234 : :
235 : : /* This table holds all the collected coroutine state for coroutines in
236 : : the current translation unit. */
237 : :
238 : : static GTY (()) hash_table<coroutine_info_hasher> *coroutine_info_table;
239 : :
240 : : /* We will initialize state lazily. */
241 : : static bool coro_initialized = false;
242 : :
243 : : /* Return a hash value for the entry pointed to by INFO.
244 : : The compare type is a tree, but the only trees we are going use are
245 : : function decls. We use the DECL_UID as the hash value since that is
246 : : stable across PCH. */
247 : :
248 : : hashval_t
249 : 65896 : coroutine_info_hasher::hash (coroutine_info *info)
250 : : {
251 : 65896 : return DECL_UID (info->function_decl);
252 : : }
253 : :
254 : : /* Return a hash value for the compare value COMP. */
255 : :
256 : : hashval_t
257 : 61281 : coroutine_info_hasher::hash (const compare_type& comp)
258 : : {
259 : 61281 : return DECL_UID (comp);
260 : : }
261 : :
262 : : /* Return true if the entries pointed to by LHS and RHS are for the
263 : : same coroutine. */
264 : :
265 : : bool
266 : : coroutine_info_hasher::equal (coroutine_info *lhs, coroutine_info *rhs)
267 : : {
268 : : return lhs->function_decl == rhs->function_decl;
269 : : }
270 : :
271 : : bool
272 : 82462 : coroutine_info_hasher::equal (coroutine_info *lhs, const compare_type& rhs)
273 : : {
274 : 82462 : return lhs->function_decl == rhs;
275 : : }
276 : :
277 : : /* Get the existing coroutine_info for FN_DECL, or insert a new one if the
278 : : entry does not yet exist. */
279 : :
280 : : coroutine_info *
281 : 10181 : get_or_insert_coroutine_info (tree fn_decl)
282 : : {
283 : 10181 : gcc_checking_assert (coroutine_info_table != NULL);
284 : :
285 : 10181 : coroutine_info **slot = coroutine_info_table->find_slot_with_hash
286 : 10181 : (fn_decl, coroutine_info_hasher::hash (fn_decl), INSERT);
287 : :
288 : 10181 : if (*slot == NULL)
289 : : {
290 : 3116 : *slot = new (ggc_cleared_alloc<coroutine_info> ()) coroutine_info ();
291 : 3116 : (*slot)->function_decl = fn_decl;
292 : : }
293 : :
294 : 10181 : return *slot;
295 : : }
296 : :
297 : : /* Get the existing coroutine_info for FN_DECL, fail if it doesn't exist. */
298 : :
299 : : coroutine_info *
300 : 51100 : get_coroutine_info (tree fn_decl)
301 : : {
302 : 51100 : if (coroutine_info_table == NULL)
303 : : return NULL;
304 : :
305 : 51100 : coroutine_info **slot = coroutine_info_table->find_slot_with_hash
306 : 51100 : (fn_decl, coroutine_info_hasher::hash (fn_decl), NO_INSERT);
307 : 51100 : if (slot)
308 : 51100 : return *slot;
309 : : return NULL;
310 : : }
311 : :
312 : : /* We will lazily create all the identifiers that are used by coroutines
313 : : on the first attempt to lookup the traits. */
314 : :
315 : : /* Identifiers that are used by all coroutines. */
316 : :
317 : : static GTY(()) tree coro_traits_identifier;
318 : : static GTY(()) tree coro_handle_identifier;
319 : : static GTY(()) tree coro_promise_type_identifier;
320 : :
321 : : /* Required promise method name identifiers. */
322 : :
323 : : static GTY(()) tree coro_await_transform_identifier;
324 : : static GTY(()) tree coro_initial_suspend_identifier;
325 : : static GTY(()) tree coro_final_suspend_identifier;
326 : : static GTY(()) tree coro_return_void_identifier;
327 : : static GTY(()) tree coro_return_value_identifier;
328 : : static GTY(()) tree coro_yield_value_identifier;
329 : : static GTY(()) tree coro_address_identifier;
330 : : static GTY(()) tree coro_from_address_identifier;
331 : : static GTY(()) tree coro_get_return_object_identifier;
332 : : static GTY(()) tree coro_gro_on_allocation_fail_identifier;
333 : : static GTY(()) tree coro_unhandled_exception_identifier;
334 : :
335 : : /* Awaitable methods. */
336 : :
337 : : static GTY(()) tree coro_await_ready_identifier;
338 : : static GTY(()) tree coro_await_suspend_identifier;
339 : : static GTY(()) tree coro_await_resume_identifier;
340 : :
341 : : /* Accessors for the coroutine frame state used by the implementation. */
342 : :
343 : : static GTY(()) tree coro_resume_fn_id;
344 : : static GTY(()) tree coro_destroy_fn_id;
345 : : static GTY(()) tree coro_promise_id;
346 : : static GTY(()) tree coro_frame_needs_free_id;
347 : : static GTY(()) tree coro_resume_index_id;
348 : : static GTY(()) tree coro_self_handle_id;
349 : : static GTY(()) tree coro_actor_continue_id;
350 : : static GTY(()) tree coro_frame_i_a_r_c_id;
351 : :
352 : : /* Create the identifiers used by the coroutines library interfaces and
353 : : the implementation frame state. */
354 : :
355 : : static void
356 : 2762 : coro_init_identifiers ()
357 : : {
358 : 2762 : coro_traits_identifier = get_identifier ("coroutine_traits");
359 : 2762 : coro_handle_identifier = get_identifier ("coroutine_handle");
360 : 2762 : coro_promise_type_identifier = get_identifier ("promise_type");
361 : :
362 : 2762 : coro_await_transform_identifier = get_identifier ("await_transform");
363 : 2762 : coro_initial_suspend_identifier = get_identifier ("initial_suspend");
364 : 2762 : coro_final_suspend_identifier = get_identifier ("final_suspend");
365 : 2762 : coro_return_void_identifier = get_identifier ("return_void");
366 : 2762 : coro_return_value_identifier = get_identifier ("return_value");
367 : 2762 : coro_yield_value_identifier = get_identifier ("yield_value");
368 : 2762 : coro_address_identifier = get_identifier ("address");
369 : 2762 : coro_from_address_identifier = get_identifier ("from_address");
370 : 2762 : coro_get_return_object_identifier = get_identifier ("get_return_object");
371 : 5524 : coro_gro_on_allocation_fail_identifier =
372 : 2762 : get_identifier ("get_return_object_on_allocation_failure");
373 : 2762 : coro_unhandled_exception_identifier = get_identifier ("unhandled_exception");
374 : :
375 : 2762 : coro_await_ready_identifier = get_identifier ("await_ready");
376 : 2762 : coro_await_suspend_identifier = get_identifier ("await_suspend");
377 : 2762 : coro_await_resume_identifier = get_identifier ("await_resume");
378 : :
379 : : /* Coroutine state frame field accessors. */
380 : 2762 : coro_resume_fn_id = get_identifier ("_Coro_resume_fn");
381 : 2762 : coro_destroy_fn_id = get_identifier ("_Coro_destroy_fn");
382 : 2762 : coro_promise_id = get_identifier ("_Coro_promise");
383 : 2762 : coro_frame_needs_free_id = get_identifier ("_Coro_frame_needs_free");
384 : 2762 : coro_frame_i_a_r_c_id = get_identifier ("_Coro_initial_await_resume_called");
385 : 2762 : coro_resume_index_id = get_identifier ("_Coro_resume_index");
386 : 2762 : coro_self_handle_id = get_identifier ("_Coro_self_handle");
387 : 2762 : coro_actor_continue_id = get_identifier ("_Coro_actor_continue");
388 : 2762 : }
389 : :
390 : : /* Trees we only need to set up once. */
391 : :
392 : : static GTY(()) tree coro_traits_templ;
393 : : static GTY(()) tree coro_handle_templ;
394 : : static GTY(()) tree void_coro_handle_type;
395 : : static GTY(()) tree void_coro_handle_address;
396 : :
397 : : /* ================= Parse, Semantics and Type checking ================= */
398 : :
399 : : /* This initial set of routines are helper for the parsing and template
400 : : expansion phases.
401 : :
402 : : At the completion of this, we will have completed trees for each of the
403 : : keywords, but making use of proxy variables for the self-handle and the
404 : : promise class instance. */
405 : :
406 : : /* [coroutine.traits]
407 : : Lookup the coroutine_traits template decl. */
408 : :
409 : : static tree
410 : 2762 : find_coro_traits_template_decl (location_t kw)
411 : : {
412 : : /* If we are missing fundamental information, such as the traits, (or the
413 : : declaration found is not a type template), then don't emit an error for
414 : : every keyword in a TU, just do it once. */
415 : 2762 : static bool traits_error_emitted = false;
416 : :
417 : 5524 : tree traits_decl = lookup_qualified_name (std_node, coro_traits_identifier,
418 : : LOOK_want::NORMAL,
419 : 2762 : /*complain=*/!traits_error_emitted);
420 : 2762 : if (traits_decl == error_mark_node
421 : 2762 : || !DECL_TYPE_TEMPLATE_P (traits_decl))
422 : : {
423 : 30 : if (!traits_error_emitted)
424 : : {
425 : 12 : auto_diagnostic_group d;
426 : 12 : gcc_rich_location richloc (kw);
427 : 12 : error_at (&richloc, "coroutines require a traits template; cannot"
428 : : " find %<%E::%E%>", std_node, coro_traits_identifier);
429 : 12 : inform (&richloc, "perhaps %<#include <coroutine>%> is missing");
430 : 12 : traits_error_emitted = true;
431 : 12 : }
432 : 30 : return NULL_TREE;
433 : : }
434 : : else
435 : : return traits_decl;
436 : : }
437 : :
438 : : /* Instantiate Coroutine traits for the function signature. */
439 : :
440 : : static tree
441 : 3116 : instantiate_coro_traits (tree fndecl, location_t kw)
442 : : {
443 : : /* [coroutine.traits.primary]
444 : : So now build up a type list for the template <typename _R, typename...>.
445 : : The types are the function's arg types and _R is the function return
446 : : type. */
447 : :
448 : 3116 : tree functyp = TREE_TYPE (fndecl);
449 : 3116 : tree arg = DECL_ARGUMENTS (fndecl);
450 : 3116 : tree arg_node = TYPE_ARG_TYPES (functyp);
451 : 3116 : tree argtypes = make_tree_vec (list_length (arg_node)-1);
452 : 3116 : unsigned p = 0;
453 : :
454 : 25156 : while (arg_node != NULL_TREE && !VOID_TYPE_P (TREE_VALUE (arg_node)))
455 : : {
456 : 7904 : if (is_this_parameter (arg)
457 : 7904 : || DECL_NAME (arg) == closure_identifier)
458 : : {
459 : : /* We pass a reference to *this to the param preview. */
460 : 1646 : tree ct = TREE_TYPE (TREE_TYPE (arg));
461 : 1646 : TREE_VEC_ELT (argtypes, p++) = cp_build_reference_type (ct, false);
462 : : }
463 : : else
464 : 6258 : TREE_VEC_ELT (argtypes, p++) = TREE_VALUE (arg_node);
465 : :
466 : 7904 : arg_node = TREE_CHAIN (arg_node);
467 : 7904 : arg = DECL_CHAIN (arg);
468 : : }
469 : :
470 : 3116 : tree argtypepack = cxx_make_type (TYPE_ARGUMENT_PACK);
471 : 3116 : ARGUMENT_PACK_ARGS (argtypepack) = argtypes;
472 : :
473 : 3116 : tree targ = make_tree_vec (2);
474 : 3116 : TREE_VEC_ELT (targ, 0) = TREE_TYPE (functyp);
475 : 3116 : TREE_VEC_ELT (targ, 1) = argtypepack;
476 : :
477 : 3116 : tree traits_class
478 : 3116 : = lookup_template_class (coro_traits_templ, targ,
479 : : /*in_decl=*/NULL_TREE, /*context=*/NULL_TREE,
480 : : tf_warning_or_error);
481 : :
482 : 3116 : if (traits_class == error_mark_node)
483 : : {
484 : 0 : error_at (kw, "cannot instantiate %<coroutine traits%>");
485 : 0 : return NULL_TREE;
486 : : }
487 : :
488 : : return traits_class;
489 : : }
490 : :
491 : : /* [coroutine.handle] */
492 : :
493 : : static tree
494 : 2732 : find_coro_handle_template_decl (location_t kw)
495 : : {
496 : : /* As for the coroutine traits, this error is per TU, so only emit
497 : : it once. */
498 : 2732 : static bool coro_handle_error_emitted = false;
499 : 5464 : tree handle_decl = lookup_qualified_name (std_node, coro_handle_identifier,
500 : : LOOK_want::NORMAL,
501 : 2732 : !coro_handle_error_emitted);
502 : 2732 : if (handle_decl == error_mark_node
503 : 2732 : || !DECL_CLASS_TEMPLATE_P (handle_decl))
504 : : {
505 : 18 : if (!coro_handle_error_emitted)
506 : 6 : error_at (kw, "coroutines require a handle class template;"
507 : : " cannot find %<%E::%E%>", std_node, coro_handle_identifier);
508 : 18 : coro_handle_error_emitted = true;
509 : 18 : return NULL_TREE;
510 : : }
511 : : else
512 : : return handle_decl;
513 : : }
514 : :
515 : : /* Get and validate HANDLE_TYPE::address. The resulting function, if any, will
516 : : be a non-overloaded member function that takes no arguments and returns
517 : : void*. If that is not the case, signals an error and returns NULL_TREE. */
518 : :
519 : : static tree
520 : 2714 : get_handle_type_address (location_t kw, tree handle_type)
521 : : {
522 : 2714 : tree addr_getter = lookup_member (handle_type, coro_address_identifier, 1,
523 : : 0, tf_warning_or_error);
524 : 2714 : if (!addr_getter || addr_getter == error_mark_node)
525 : : {
526 : 18 : qualified_name_lookup_error (handle_type, coro_address_identifier,
527 : : error_mark_node, kw);
528 : 18 : return NULL_TREE;
529 : : }
530 : :
531 : 2696 : if (!BASELINK_P (addr_getter)
532 : 2696 : || TREE_CODE (TREE_TYPE (addr_getter)) != METHOD_TYPE)
533 : : {
534 : 18 : error_at (kw, "%qE must be a non-overloaded method", addr_getter);
535 : 18 : return NULL_TREE;
536 : : }
537 : :
538 : 2678 : tree fn_t = TREE_TYPE (addr_getter);
539 : 2678 : tree arg = TYPE_ARG_TYPES (fn_t);
540 : :
541 : : /* Skip the 'this' pointer. */
542 : 2678 : arg = TREE_CHAIN (arg);
543 : :
544 : : /* Check that from_addr has the argument list (). */
545 : 2678 : if (arg != void_list_node)
546 : : {
547 : 0 : error_at (kw, "%qE must take no arguments", addr_getter);
548 : 0 : return NULL_TREE;
549 : : }
550 : :
551 : 2678 : tree ret_t = TREE_TYPE (fn_t);
552 : 2678 : if (!same_type_p (ret_t, ptr_type_node))
553 : : {
554 : 0 : error_at (kw, "%qE must return %qT, not %qT",
555 : : addr_getter, ptr_type_node, ret_t);
556 : 0 : return NULL_TREE;
557 : : }
558 : :
559 : : return addr_getter;
560 : : }
561 : :
562 : : /* Get and validate HANDLE_TYPE::from_address. The resulting function, if
563 : : any, will be a non-overloaded static function that takes a single void* and
564 : : returns HANDLE_TYPE. If that is not the case, signals an error and returns
565 : : NULL_TREE. */
566 : :
567 : : static tree
568 : 1577 : get_handle_type_from_address (location_t kw, tree handle_type)
569 : : {
570 : 1577 : tree from_addr = lookup_member (handle_type, coro_from_address_identifier, 1,
571 : : 0, tf_warning_or_error);
572 : 1577 : if (!from_addr || from_addr == error_mark_node)
573 : : {
574 : 6 : qualified_name_lookup_error (handle_type, coro_from_address_identifier,
575 : : error_mark_node, kw);
576 : 6 : return NULL_TREE;
577 : : }
578 : 1571 : if (!BASELINK_P (from_addr)
579 : 1571 : || TREE_CODE (TREE_TYPE (from_addr)) != FUNCTION_TYPE)
580 : : {
581 : 3 : error_at (kw, "%qE must be a non-overloaded static function", from_addr);
582 : 3 : return NULL_TREE;
583 : : }
584 : :
585 : 1568 : tree fn_t = TREE_TYPE (from_addr);
586 : 1568 : tree arg = TYPE_ARG_TYPES (fn_t);
587 : : /* Check that from_addr has the argument list (void*). */
588 : 1568 : if (!arg
589 : 1568 : || !same_type_p (TREE_VALUE (arg), ptr_type_node)
590 : 3136 : || TREE_CHAIN (arg) != void_list_node)
591 : : {
592 : 0 : error_at (kw, "%qE must take a single %qT", from_addr, ptr_type_node);
593 : 0 : return NULL_TREE;
594 : : }
595 : :
596 : 1568 : tree ret_t = TREE_TYPE (fn_t);
597 : 1568 : if (!same_type_p (ret_t, handle_type))
598 : : {
599 : 0 : error_at (kw, "%qE must return %qT, not %qT",
600 : : from_addr, handle_type, ret_t);
601 : 0 : return NULL_TREE;
602 : : }
603 : :
604 : : return from_addr;
605 : : }
606 : :
607 : : static tree
608 : 4291 : instantiate_coro_handle_for_promise_type (location_t kw, tree promise_type)
609 : : {
610 : : /* So now build up a type list for the template, one entry, the promise. */
611 : 4291 : tree targ = make_tree_vec (1);
612 : 4291 : TREE_VEC_ELT (targ, 0) = promise_type;
613 : 4291 : tree handle_type
614 : 4291 : = lookup_template_class (coro_handle_identifier, targ,
615 : : /* in_decl=*/NULL_TREE,
616 : : /* context=*/std_node,
617 : : tf_warning_or_error);
618 : :
619 : 4291 : if (handle_type == error_mark_node)
620 : : {
621 : 0 : error_at (kw, "cannot instantiate a %<coroutine handle%> for"
622 : : " promise type %qT", promise_type);
623 : 0 : return NULL_TREE;
624 : : }
625 : :
626 : : return handle_type;
627 : : }
628 : :
629 : : /* Look for the promise_type in the instantiated traits. */
630 : :
631 : : static tree
632 : 1601 : find_promise_type (tree traits_class)
633 : : {
634 : 1601 : tree promise_type
635 : 1601 : = lookup_member (traits_class, coro_promise_type_identifier,
636 : : /* protect=*/1, /*want_type=*/true, tf_warning_or_error);
637 : :
638 : 1601 : if (promise_type)
639 : 1583 : promise_type
640 : 1583 : = complete_type_or_else (TREE_TYPE (promise_type), promise_type);
641 : :
642 : : /* NULL_TREE on fail. */
643 : 1601 : return promise_type;
644 : : }
645 : :
646 : : /* Perform initialization of the coroutine processor state, if not done
647 : : before. */
648 : :
649 : : static bool
650 : 8664 : ensure_coro_initialized (location_t loc)
651 : : {
652 : 8664 : if (!coro_initialized)
653 : : {
654 : : /* Trees we only need to create once.
655 : : Set up the identifiers we will use. */
656 : 2762 : coro_init_identifiers ();
657 : :
658 : : /* Coroutine traits template. */
659 : 2762 : coro_traits_templ = find_coro_traits_template_decl (loc);
660 : 2762 : if (coro_traits_templ == NULL_TREE)
661 : : return false;
662 : :
663 : : /* coroutine_handle<> template. */
664 : 2732 : coro_handle_templ = find_coro_handle_template_decl (loc);
665 : 2732 : if (coro_handle_templ == NULL_TREE)
666 : : return false;
667 : :
668 : : /* We can also instantiate the void coroutine_handle<> */
669 : 2714 : void_coro_handle_type
670 : 2714 : = instantiate_coro_handle_for_promise_type (loc, void_type_node);
671 : 2714 : if (void_coro_handle_type == NULL_TREE)
672 : : return false;
673 : :
674 : 2714 : void_coro_handle_address
675 : 2714 : = get_handle_type_address (loc, void_coro_handle_type);
676 : 2714 : if (!void_coro_handle_address)
677 : : return false;
678 : :
679 : : /* A table to hold the state, per coroutine decl. */
680 : 2678 : gcc_checking_assert (coroutine_info_table == NULL);
681 : 5356 : coroutine_info_table =
682 : 2678 : hash_table<coroutine_info_hasher>::create_ggc (11);
683 : :
684 : 2678 : if (coroutine_info_table == NULL)
685 : : return false;
686 : :
687 : 2678 : coro_initialized = true;
688 : : }
689 : : return true;
690 : : }
691 : :
692 : : /* Try to get the coroutine traits class. */
693 : : static tree
694 : 5948 : coro_get_traits_class (tree fndecl, location_t loc)
695 : : {
696 : 5948 : gcc_assert (fndecl != NULL_TREE);
697 : 5948 : gcc_assert (coro_initialized);
698 : :
699 : 5948 : coroutine_info *coro_info = get_or_insert_coroutine_info (fndecl);
700 : 5948 : auto& traits_type = coro_info->traits_type;
701 : 5948 : if (!traits_type)
702 : 3116 : traits_type = instantiate_coro_traits (fndecl, loc);
703 : 5948 : return traits_type;
704 : : }
705 : :
706 : : static bool
707 : 4269 : coro_promise_type_found_p (tree fndecl, location_t loc)
708 : : {
709 : 4269 : gcc_assert (fndecl != NULL_TREE);
710 : :
711 : 4269 : if (!ensure_coro_initialized (loc))
712 : : return false;
713 : :
714 : : /* Save the coroutine data on the side to avoid the overhead on every
715 : : function decl tree. */
716 : :
717 : 4233 : coroutine_info *coro_info = get_or_insert_coroutine_info (fndecl);
718 : : /* Without this, we cannot really proceed. */
719 : 4233 : gcc_checking_assert (coro_info);
720 : :
721 : : /* If we don't already have a current promise type, try to look it up. */
722 : 4233 : if (coro_info->promise_type == NULL_TREE)
723 : : {
724 : : /* Get the coroutine traits template class instance for the function
725 : : signature we have - coroutine_traits <R, ...> */
726 : :
727 : 1601 : tree templ_class = coro_get_traits_class (fndecl, loc);
728 : :
729 : : /* Find the promise type for that. */
730 : 1601 : coro_info->promise_type = find_promise_type (templ_class);
731 : :
732 : : /* If we don't find it, punt on the rest. */
733 : 1601 : if (coro_info->promise_type == NULL_TREE)
734 : : {
735 : 18 : if (!coro_info->coro_promise_error_emitted)
736 : 6 : error_at (loc, "unable to find the promise type for"
737 : : " this coroutine");
738 : 18 : coro_info->coro_promise_error_emitted = true;
739 : 18 : return false;
740 : : }
741 : :
742 : : /* Test for errors in the promise type that can be determined now. */
743 : 1583 : tree has_ret_void = lookup_member (coro_info->promise_type,
744 : : coro_return_void_identifier,
745 : : /*protect=*/1, /*want_type=*/0,
746 : : tf_none);
747 : 1583 : tree has_ret_val = lookup_member (coro_info->promise_type,
748 : : coro_return_value_identifier,
749 : : /*protect=*/1, /*want_type=*/0,
750 : : tf_none);
751 : 1583 : if (has_ret_void && has_ret_val)
752 : : {
753 : 6 : auto_diagnostic_group d;
754 : 6 : location_t ploc = DECL_SOURCE_LOCATION (fndecl);
755 : 6 : if (!coro_info->coro_co_return_error_emitted)
756 : 6 : error_at (ploc, "the coroutine promise type %qT declares both"
757 : : " %<return_value%> and %<return_void%>",
758 : : coro_info->promise_type);
759 : 6 : inform (DECL_SOURCE_LOCATION (BASELINK_FUNCTIONS (has_ret_void)),
760 : : "%<return_void%> declared here");
761 : 6 : has_ret_val = BASELINK_FUNCTIONS (has_ret_val);
762 : 6 : const char *message = "%<return_value%> declared here";
763 : 6 : if (TREE_CODE (has_ret_val) == OVERLOAD)
764 : : {
765 : 6 : has_ret_val = OVL_FIRST (has_ret_val);
766 : : message = "%<return_value%> first declared here";
767 : : }
768 : 6 : inform (DECL_SOURCE_LOCATION (has_ret_val), message);
769 : 6 : coro_info->coro_co_return_error_emitted = true;
770 : 6 : return false;
771 : 6 : }
772 : :
773 : : /* Try to find the handle type for the promise. */
774 : 1577 : tree handle_type
775 : 1577 : = instantiate_coro_handle_for_promise_type (loc, coro_info->promise_type);
776 : 1577 : if (handle_type == NULL_TREE)
777 : : return false;
778 : 1577 : tree from_address = get_handle_type_from_address (loc, handle_type);
779 : 1577 : if (from_address == NULL_TREE)
780 : : return false;
781 : :
782 : : /* Complete this, we're going to use it. */
783 : 1568 : coro_info->handle_type = complete_type_or_else (handle_type, fndecl);
784 : 1568 : coro_info->from_address = from_address;
785 : :
786 : : /* Diagnostic would be emitted by complete_type_or_else. */
787 : 1568 : if (!coro_info->handle_type)
788 : : return false;
789 : :
790 : : /* Build a proxy for a handle to "self" as the param to
791 : : await_suspend() calls. */
792 : 1568 : coro_info->self_h_proxy
793 : 1568 : = build_lang_decl (VAR_DECL, coro_self_handle_id,
794 : : coro_info->handle_type);
795 : :
796 : : /* Build a proxy for the promise so that we can perform lookups. */
797 : 1568 : coro_info->promise_proxy
798 : 1568 : = build_lang_decl (VAR_DECL, coro_promise_id,
799 : : coro_info->promise_type);
800 : :
801 : : /* Note where we first saw a coroutine keyword. */
802 : 1568 : coro_info->first_coro_keyword = loc;
803 : : }
804 : :
805 : : return true;
806 : : }
807 : :
808 : : /* Map from actor or destroyer to ramp. */
809 : : static GTY(()) hash_map<tree, tree> *to_ramp;
810 : :
811 : : /* Given a tree that is an actor or destroy, find the ramp function. */
812 : :
813 : : tree
814 : 197523576 : coro_get_ramp_function (tree decl)
815 : : {
816 : 197523576 : if (!to_ramp)
817 : : return NULL_TREE;
818 : 875124 : tree *p = to_ramp->get (decl);
819 : 875124 : if (p)
820 : 3200 : return *p;
821 : : return NULL_TREE;
822 : : }
823 : :
824 : : /* Given the DECL for a ramp function (the user's original declaration) return
825 : : the actor function if it has been defined. */
826 : :
827 : : tree
828 : 2828 : coro_get_actor_function (tree decl)
829 : : {
830 : 2828 : if (coroutine_info *info = get_coroutine_info (decl))
831 : 2828 : return info->actor_decl;
832 : :
833 : : return NULL_TREE;
834 : : }
835 : :
836 : : /* Given the DECL for a ramp function (the user's original declaration) return
837 : : the destroy function if it has been defined. */
838 : :
839 : : tree
840 : 1414 : coro_get_destroy_function (tree decl)
841 : : {
842 : 1414 : if (coroutine_info *info = get_coroutine_info (decl))
843 : 1414 : return info->destroy_decl;
844 : :
845 : : return NULL_TREE;
846 : : }
847 : :
848 : : /* Given a CO_AWAIT_EXPR AWAIT_EXPR, return its resume call. */
849 : :
850 : : tree
851 : 230 : co_await_get_resume_call (tree await_expr)
852 : : {
853 : 230 : gcc_checking_assert (TREE_CODE (await_expr) == CO_AWAIT_EXPR);
854 : 230 : tree vec = TREE_OPERAND (await_expr, 3);
855 : 230 : if (!vec)
856 : : return nullptr;
857 : 218 : return TREE_VEC_ELT (vec, 2);
858 : : }
859 : :
860 : :
861 : : /* These functions assumes that the caller has verified that the state for
862 : : the decl has been initialized, we try to minimize work here. */
863 : :
864 : : static tree
865 : 20682 : get_coroutine_promise_type (tree decl)
866 : : {
867 : 20682 : if (coroutine_info *info = get_coroutine_info (decl))
868 : 19144 : return info->promise_type;
869 : :
870 : : return NULL_TREE;
871 : : }
872 : :
873 : : static tree
874 : 1553 : get_coroutine_handle_type (tree decl)
875 : : {
876 : 1553 : if (coroutine_info *info = get_coroutine_info (decl))
877 : 0 : return info->handle_type;
878 : :
879 : : return NULL_TREE;
880 : : }
881 : :
882 : : static tree
883 : 5694 : get_coroutine_self_handle_proxy (tree decl)
884 : : {
885 : 5694 : if (coroutine_info *info = get_coroutine_info (decl))
886 : 5694 : return info->self_h_proxy;
887 : :
888 : : return NULL_TREE;
889 : : }
890 : :
891 : : static tree
892 : 8287 : get_coroutine_promise_proxy (tree decl)
893 : : {
894 : 8287 : if (coroutine_info *info = get_coroutine_info (decl))
895 : 8287 : return info->promise_proxy;
896 : :
897 : : return NULL_TREE;
898 : : }
899 : :
900 : : static tree
901 : 1511 : get_coroutine_from_address (tree decl)
902 : : {
903 : 1511 : if (coroutine_info *info = get_coroutine_info (decl))
904 : 0 : return info->from_address;
905 : :
906 : : return NULL_TREE;
907 : : }
908 : :
909 : : static tree
910 : 13037 : lookup_promise_method (tree fndecl, tree member_id, location_t loc,
911 : : bool musthave)
912 : : {
913 : 13037 : tree promise = get_coroutine_promise_type (fndecl);
914 : 13037 : tree pm_memb
915 : 13037 : = lookup_member (promise, member_id,
916 : : /*protect=*/1, /*want_type=*/0, tf_warning_or_error);
917 : 13037 : if (musthave && pm_memb == NULL_TREE)
918 : : {
919 : 21 : error_at (loc, "no member named %qE in %qT", member_id, promise);
920 : 21 : return error_mark_node;
921 : : }
922 : : return pm_memb;
923 : : }
924 : :
925 : : /* Build an expression of the form p.method (args) where the p is a promise
926 : : object for the current coroutine.
927 : : OBJECT is the promise object instance to use, it may be NULL, in which case
928 : : we will use the promise_proxy instance for this coroutine.
929 : : ARGS may be NULL, for empty parm lists. */
930 : :
931 : : static tree
932 : 9040 : coro_build_promise_expression (tree fn, tree promise_obj, tree member_id,
933 : : location_t loc, vec<tree, va_gc> **args,
934 : : bool musthave)
935 : : {
936 : 9040 : tree meth = lookup_promise_method (fn, member_id, loc, musthave);
937 : 9040 : if (meth == error_mark_node)
938 : : return error_mark_node;
939 : :
940 : : /* If we don't find it, and it isn't needed, an empty return is OK. */
941 : 9022 : if (!meth)
942 : : return NULL_TREE;
943 : :
944 : 8109 : tree promise
945 : 8109 : = promise_obj ? promise_obj
946 : 5049 : : get_coroutine_promise_proxy (current_function_decl);
947 : 8109 : tree expr;
948 : 8109 : if (BASELINK_P (meth))
949 : 8011 : expr = build_new_method_call (promise, meth, args, NULL_TREE,
950 : : LOOKUP_NORMAL, NULL, tf_warning_or_error);
951 : : else
952 : : {
953 : 98 : expr = build_class_member_access_expr (promise, meth, NULL_TREE,
954 : : true, tf_warning_or_error);
955 : 98 : vec<tree, va_gc> *real_args;
956 : 98 : if (!args)
957 : 70 : real_args = make_tree_vector ();
958 : : else
959 : 28 : real_args = *args;
960 : 98 : expr = build_op_call (expr, &real_args, tf_warning_or_error);
961 : : }
962 : : return expr;
963 : : }
964 : :
965 : : /* Caching get for the expression p.return_void (). */
966 : :
967 : : static tree
968 : 1958 : get_coroutine_return_void_expr (tree decl, location_t loc, bool musthave)
969 : : {
970 : 1958 : if (coroutine_info *info = get_coroutine_info (decl))
971 : : {
972 : : /* If we don't have it try to build it. */
973 : 1958 : if (!info->return_void)
974 : 1541 : info->return_void
975 : 1541 : = coro_build_promise_expression (current_function_decl, NULL,
976 : : coro_return_void_identifier,
977 : : loc, NULL, musthave);
978 : : /* Don't return an error if it's an optional call. */
979 : 1958 : if (!musthave && info->return_void == error_mark_node)
980 : : return NULL_TREE;
981 : 1955 : return info->return_void;
982 : : }
983 : 0 : return musthave ? error_mark_node : NULL_TREE;
984 : : }
985 : :
986 : : /* Lookup an Awaitable member, which should be await_ready, await_suspend
987 : : or await_resume. */
988 : :
989 : : static tree
990 : 12504 : lookup_awaitable_member (tree await_type, tree member_id, location_t loc)
991 : : {
992 : 12504 : tree aw_memb
993 : 12504 : = lookup_member (await_type, member_id,
994 : : /*protect=*/1, /*want_type=*/0, tf_warning_or_error);
995 : 12504 : if (aw_memb == NULL_TREE)
996 : : {
997 : 9 : error_at (loc, "no member named %qE in %qT", member_id, await_type);
998 : 9 : return error_mark_node;
999 : : }
1000 : : return aw_memb;
1001 : : }
1002 : :
1003 : : /* Here we check the constraints that are common to all keywords (since the
1004 : : presence of a coroutine keyword makes the function into a coroutine). */
1005 : :
1006 : : static bool
1007 : 4470 : coro_common_keyword_context_valid_p (tree fndecl, location_t kw_loc,
1008 : : const char *kw_name)
1009 : : {
1010 : 4470 : if (fndecl == NULL_TREE)
1011 : : {
1012 : 12 : error_at (kw_loc, "%qs cannot be used outside a function", kw_name);
1013 : 12 : return false;
1014 : : }
1015 : :
1016 : : /* This is arranged in order of prohibitions in the std. */
1017 : 4458 : if (DECL_MAIN_P (fndecl))
1018 : : {
1019 : : /* [basic.start.main] 3. The function main shall not be a coroutine. */
1020 : 9 : error_at (kw_loc, "%qs cannot be used in the %<main%> function",
1021 : : kw_name);
1022 : 9 : return false;
1023 : : }
1024 : :
1025 : 4449 : if (DECL_DECLARED_CONSTEXPR_P (fndecl))
1026 : : {
1027 : 15 : cp_function_chain->invalid_constexpr = true;
1028 : 15 : if (!is_instantiation_of_constexpr (fndecl))
1029 : : {
1030 : : /* [dcl.constexpr] 3.3 it shall not be a coroutine. */
1031 : 9 : error_at (kw_loc, "%qs cannot be used in a %<constexpr%> function",
1032 : : kw_name);
1033 : 9 : return false;
1034 : : }
1035 : : }
1036 : :
1037 : 4440 : if (FNDECL_USED_AUTO (fndecl))
1038 : : {
1039 : : /* [dcl.spec.auto] 15. A function declared with a return type that uses
1040 : : a placeholder type shall not be a coroutine. */
1041 : 18 : error_at (kw_loc,
1042 : : "%qs cannot be used in a function with a deduced return type",
1043 : : kw_name);
1044 : 18 : return false;
1045 : : }
1046 : :
1047 : 4422 : if (varargs_function_p (fndecl))
1048 : : {
1049 : : /* [dcl.fct.def.coroutine] The parameter-declaration-clause of the
1050 : : coroutine shall not terminate with an ellipsis that is not part
1051 : : of a parameter-declaration. */
1052 : 9 : error_at (kw_loc,
1053 : : "%qs cannot be used in a varargs function", kw_name);
1054 : 9 : return false;
1055 : : }
1056 : :
1057 : 8826 : if (DECL_CONSTRUCTOR_P (fndecl))
1058 : : {
1059 : : /* [class.ctor] 7. a constructor shall not be a coroutine. */
1060 : 9 : error_at (kw_loc, "%qs cannot be used in a constructor", kw_name);
1061 : 9 : return false;
1062 : : }
1063 : :
1064 : 4404 : if (DECL_DESTRUCTOR_P (fndecl))
1065 : : {
1066 : : /* [class.dtor] 21. a destructor shall not be a coroutine. */
1067 : 9 : error_at (kw_loc, "%qs cannot be used in a destructor", kw_name);
1068 : 9 : return false;
1069 : : }
1070 : :
1071 : : return true;
1072 : : }
1073 : :
1074 : : /* Here we check the constraints that are not per keyword. */
1075 : :
1076 : : static bool
1077 : 1595 : coro_function_valid_p (tree fndecl)
1078 : : {
1079 : 1595 : location_t f_loc = DECL_SOURCE_LOCATION (fndecl);
1080 : :
1081 : : /* For cases where fundamental information cannot be found, e.g. the
1082 : : coroutine traits are missing, we need to punt early. */
1083 : 1595 : if (!coro_promise_type_found_p (fndecl, f_loc))
1084 : : return false;
1085 : :
1086 : : /* Since we think the function is a coroutine, that implies we parsed
1087 : : a keyword that triggered this. Keywords check promise validity for
1088 : : their context and thus the promise type should be known at this point. */
1089 : 1553 : if (get_coroutine_handle_type (fndecl) == NULL_TREE
1090 : 3091 : || get_coroutine_promise_type (fndecl) == NULL_TREE)
1091 : 15 : return false;
1092 : :
1093 : 1538 : if (current_function_returns_value || current_function_returns_null)
1094 : : {
1095 : : /* TODO: record or extract positions of returns (and the first coro
1096 : : keyword) so that we can add notes to the diagnostic about where
1097 : : the bad keyword is and what made the function into a coro. */
1098 : 3 : error_at (f_loc, "a %<return%> statement is not allowed in coroutine;"
1099 : : " did you mean %<co_return%>?");
1100 : 3 : return false;
1101 : : }
1102 : :
1103 : : return true;
1104 : : }
1105 : :
1106 : : enum suspend_point_kind {
1107 : : CO_AWAIT_SUSPEND_POINT = 0,
1108 : : CO_YIELD_SUSPEND_POINT,
1109 : : INITIAL_SUSPEND_POINT,
1110 : : FINAL_SUSPEND_POINT
1111 : : };
1112 : :
1113 : : /* Helper function to build a named variable for the temps we use for each
1114 : : await point. The root of the name is determined by SUSPEND_KIND, and
1115 : : the variable is of type V_TYPE. The awaitable number is reset each time
1116 : : we encounter a final suspend. */
1117 : :
1118 : : static tree
1119 : 4109 : get_awaitable_var (suspend_point_kind suspend_kind, tree v_type)
1120 : : {
1121 : 4109 : auto cinfo = get_coroutine_info (current_function_decl);
1122 : 4109 : gcc_checking_assert (cinfo);
1123 : 4109 : char *buf;
1124 : 4109 : switch (suspend_kind)
1125 : : {
1126 : 730 : default: buf = xasprintf ("Aw%d", cinfo->awaitable_number++); break;
1127 : 396 : case CO_YIELD_SUSPEND_POINT:
1128 : 396 : buf = xasprintf ("Yd%d", cinfo->awaitable_number++);
1129 : 396 : break;
1130 : 1499 : case INITIAL_SUSPEND_POINT: buf = xasprintf ("Is"); break;
1131 : 1484 : case FINAL_SUSPEND_POINT: buf = xasprintf ("Fs"); break;
1132 : : }
1133 : 4109 : tree ret = get_identifier (buf);
1134 : 4109 : free (buf);
1135 : 4109 : ret = build_lang_decl (VAR_DECL, ret, v_type);
1136 : 4109 : DECL_ARTIFICIAL (ret) = true;
1137 : 4109 : return ret;
1138 : : }
1139 : :
1140 : : /* Helpers to diagnose missing noexcept on final await expressions. */
1141 : :
1142 : : static bool
1143 : 6581 : coro_diagnose_throwing_fn (tree fndecl)
1144 : : {
1145 : 6581 : if (!TYPE_NOTHROW_P (TREE_TYPE (fndecl)))
1146 : : {
1147 : 21 : auto_diagnostic_group d;
1148 : 21 : location_t f_loc = cp_expr_loc_or_loc (fndecl,
1149 : 21 : DECL_SOURCE_LOCATION (fndecl));
1150 : 21 : error_at (f_loc, "the expression %qE is required to be non-throwing",
1151 : : fndecl);
1152 : 21 : inform (f_loc, "must be declared with %<noexcept(true)%>");
1153 : 21 : return true;
1154 : 21 : }
1155 : : return false;
1156 : : }
1157 : :
1158 : : static bool
1159 : 1495 : coro_diagnose_throwing_final_aw_expr (tree expr)
1160 : : {
1161 : 1495 : if (TREE_CODE (expr) == TARGET_EXPR)
1162 : 1492 : expr = TARGET_EXPR_INITIAL (expr);
1163 : 1495 : tree fn = NULL_TREE;
1164 : 1495 : if (TREE_CODE (expr) == CALL_EXPR)
1165 : 762 : fn = CALL_EXPR_FN (expr);
1166 : 733 : else if (TREE_CODE (expr) == AGGR_INIT_EXPR)
1167 : 733 : fn = AGGR_INIT_EXPR_FN (expr);
1168 : 0 : else if (TREE_CODE (expr) == CONSTRUCTOR)
1169 : : return false;
1170 : : else
1171 : : {
1172 : 0 : gcc_checking_assert (0 && "unhandled expression type");
1173 : : return false;
1174 : : }
1175 : 1495 : fn = TREE_OPERAND (fn, 0);
1176 : 1495 : return coro_diagnose_throwing_fn (fn);
1177 : : }
1178 : :
1179 : : /* Build a co_await suitable for later expansion. */
1180 : :
1181 : : tree
1182 : 148 : build_template_co_await_expr (location_t kw, tree type, tree expr, tree kind)
1183 : : {
1184 : 148 : tree aw_expr = build5_loc (kw, CO_AWAIT_EXPR, type, expr,
1185 : : NULL_TREE, NULL_TREE, NULL_TREE,
1186 : : kind);
1187 : 148 : TREE_SIDE_EFFECTS (aw_expr) = true;
1188 : 148 : return aw_expr;
1189 : : }
1190 : :
1191 : : /* Is EXPR an lvalue that will refer to the same object after a resume?
1192 : :
1193 : : This is close to asking tree_invariant_p of its address, but that doesn't
1194 : : distinguish temporaries from other variables. */
1195 : :
1196 : : static bool
1197 : 4162 : is_stable_lvalue (tree expr)
1198 : : {
1199 : 4162 : if (TREE_SIDE_EFFECTS (expr))
1200 : : return false;
1201 : :
1202 : 136 : for (; handled_component_p (expr);
1203 : 59 : expr = TREE_OPERAND (expr, 0))
1204 : : {
1205 : 59 : if (TREE_CODE (expr) == ARRAY_REF
1206 : 59 : && !TREE_CONSTANT (TREE_OPERAND (expr, 1)))
1207 : : return false;
1208 : : }
1209 : :
1210 : 77 : return (TREE_CODE (expr) == PARM_DECL
1211 : 77 : || (VAR_P (expr) && !is_local_temp (expr)));
1212 : : }
1213 : :
1214 : : /* This performs [expr.await] bullet 3.3 and validates the interface obtained.
1215 : : It is also used to build the initial and final suspend points.
1216 : :
1217 : : 'a', 'o' and 'e' are used as per the description in the section noted.
1218 : :
1219 : : A, the original yield/await expr, is found at source location LOC.
1220 : :
1221 : : We will be constructing a CO_AWAIT_EXPR for a suspend point of one of
1222 : : the four suspend_point_kind kinds. This is indicated by SUSPEND_KIND.
1223 : :
1224 : : In the case that we're processing a template declaration, we can't save
1225 : : actual awaiter expressions as the frame type will differ between
1226 : : instantiations, but we can generate them to type-check them and compute the
1227 : : resulting expression type. In those cases, we will return a
1228 : : template-appropriate CO_AWAIT_EXPR and throw away the rest of the results.
1229 : : Such an expression requires the original co_await operand unaltered. Pass
1230 : : it as ORIG_OPERAND. If it is the same as 'a', you can pass NULL_TREE (the
1231 : : default) to use 'a' as the value. */
1232 : :
1233 : : static tree
1234 : 4193 : build_co_await (location_t loc, tree a, suspend_point_kind suspend_kind,
1235 : : tree orig_operand = NULL_TREE)
1236 : : {
1237 : 4193 : if (orig_operand == NULL_TREE)
1238 : 3404 : orig_operand = a;
1239 : :
1240 : : /* Try and overload of operator co_await, .... */
1241 : 4193 : tree o;
1242 : 4193 : if (MAYBE_CLASS_TYPE_P (TREE_TYPE (a)))
1243 : : {
1244 : 4177 : o = build_new_op (loc, CO_AWAIT_EXPR, LOOKUP_NORMAL, a, NULL_TREE,
1245 : : NULL_TREE, NULL_TREE, NULL, tf_warning_or_error);
1246 : : /* If no viable functions are found, o is a. */
1247 : 4177 : if (!o || o == error_mark_node)
1248 : : o = a;
1249 : 135 : else if (flag_exceptions && suspend_kind == FINAL_SUSPEND_POINT)
1250 : : {
1251 : : /* We found an overload for co_await(), diagnose throwing cases. */
1252 : 21 : if (TREE_CODE (o) == TARGET_EXPR
1253 : 21 : && coro_diagnose_throwing_final_aw_expr (o))
1254 : 3 : return error_mark_node;
1255 : :
1256 : : /* We now know that the final suspend object is distinct from the
1257 : : final awaiter, so check for a non-throwing DTOR where needed. */
1258 : 18 : if (tree dummy = cxx_maybe_build_cleanup (a, tf_none))
1259 : : {
1260 : 15 : if (CONVERT_EXPR_P (dummy))
1261 : 0 : dummy = TREE_OPERAND (dummy, 0);
1262 : 15 : dummy = TREE_OPERAND (CALL_EXPR_FN (dummy), 0);
1263 : 15 : if (coro_diagnose_throwing_fn (dummy))
1264 : 3 : return error_mark_node;
1265 : : }
1266 : : }
1267 : : }
1268 : : else
1269 : : o = a; /* This is most likely about to fail anyway. */
1270 : :
1271 : 4187 : tree o_type = TREE_TYPE (o);
1272 : 4187 : if (o_type && !VOID_TYPE_P (o_type))
1273 : 4186 : o_type = complete_type_or_else (o_type, o);
1274 : :
1275 : 4187 : if (!o_type || o_type == error_mark_node)
1276 : 9 : return error_mark_node;
1277 : :
1278 : 4178 : if (TREE_CODE (o_type) != RECORD_TYPE)
1279 : : {
1280 : 7 : if (suspend_kind == FINAL_SUSPEND_POINT)
1281 : 3 : error_at (loc, "%qs awaitable type %qT is not a structure",
1282 : : "final_suspend()", o_type);
1283 : 4 : else if (suspend_kind == INITIAL_SUSPEND_POINT)
1284 : 3 : error_at (loc, "%qs awaitable type %qT is not a structure",
1285 : : "initial_suspend()", o_type);
1286 : : else
1287 : 1 : error_at (loc, "awaitable type %qT is not a structure", o_type);
1288 : 7 : return error_mark_node;
1289 : : }
1290 : :
1291 : : /* Check for required awaitable members and their types. */
1292 : 4171 : tree awrd_meth
1293 : 4171 : = lookup_awaitable_member (o_type, coro_await_ready_identifier, loc);
1294 : 4171 : if (!awrd_meth || awrd_meth == error_mark_node)
1295 : 3 : return error_mark_node;
1296 : 4168 : tree awsp_meth
1297 : 4168 : = lookup_awaitable_member (o_type, coro_await_suspend_identifier, loc);
1298 : 4168 : if (!awsp_meth || awsp_meth == error_mark_node)
1299 : 3 : return error_mark_node;
1300 : :
1301 : : /* The type of the co_await is the return type of the awaitable's
1302 : : await_resume, so we need to look that up. */
1303 : 4165 : tree awrs_meth
1304 : 4165 : = lookup_awaitable_member (o_type, coro_await_resume_identifier, loc);
1305 : 4165 : if (!awrs_meth || awrs_meth == error_mark_node)
1306 : 3 : return error_mark_node;
1307 : :
1308 : : /* [expr.await]/3.3 If o would be a prvalue, the temporary
1309 : : materialization conversion ([conv.rval]) is applied. */
1310 : 4162 : if (!glvalue_p (o))
1311 : 4062 : o = get_target_expr (o, tf_warning_or_error);
1312 : :
1313 : : /* [expr.await]/3.4 e is an lvalue referring to the result of evaluating the
1314 : : (possibly-converted) o.
1315 : :
1316 : : So, either reuse an existing stable lvalue such as a variable or
1317 : : COMPONENT_REF thereof, or create a new a coroutine state frame variable
1318 : : for the awaiter, since it must persist across suspension. */
1319 : 4162 : tree e_var = NULL_TREE;
1320 : 4162 : tree e_proxy = o;
1321 : 4162 : if (is_stable_lvalue (o))
1322 : : o = NULL_TREE; /* Use the existing entity. */
1323 : : else /* We need a non-temp var. */
1324 : : {
1325 : 4109 : tree p_type = TREE_TYPE (o);
1326 : 4109 : tree o_a = o;
1327 : 4109 : if (glvalue_p (o))
1328 : : {
1329 : : /* Build a reference variable for a non-stable lvalue o. */
1330 : 47 : p_type = cp_build_reference_type (p_type, xvalue_p (o));
1331 : 47 : o_a = build_address (o);
1332 : 47 : o_a = cp_fold_convert (p_type, o_a);
1333 : : }
1334 : 4109 : e_var = get_awaitable_var (suspend_kind, p_type);
1335 : 4109 : o = cp_build_init_expr (loc, e_var, o_a);
1336 : 4109 : e_proxy = convert_from_reference (e_var);
1337 : : }
1338 : :
1339 : : /* I suppose we could check that this is contextually convertible to bool. */
1340 : 4162 : tree awrd_func = NULL_TREE;
1341 : 4162 : tree awrd_call
1342 : 4162 : = build_new_method_call (e_proxy, awrd_meth, NULL, NULL_TREE, LOOKUP_NORMAL,
1343 : : &awrd_func, tf_warning_or_error);
1344 : :
1345 : 4162 : if (!awrd_func || !awrd_call || awrd_call == error_mark_node)
1346 : 0 : return error_mark_node;
1347 : :
1348 : : /* The suspend method may return one of three types:
1349 : : 1. void (no special action needed).
1350 : : 2. bool (if true, we don't need to suspend).
1351 : : 3. a coroutine handle, we execute the handle.resume() call. */
1352 : 4162 : tree awsp_func = NULL_TREE;
1353 : 4162 : tree h_proxy = get_coroutine_self_handle_proxy (current_function_decl);
1354 : 4162 : vec<tree, va_gc> *args = make_tree_vector_single (h_proxy);
1355 : 4162 : tree awsp_call
1356 : 4162 : = build_new_method_call (e_proxy, awsp_meth, &args, NULL_TREE,
1357 : : LOOKUP_NORMAL, &awsp_func, tf_warning_or_error);
1358 : :
1359 : 4162 : release_tree_vector (args);
1360 : 4162 : if (!awsp_func || !awsp_call || awsp_call == error_mark_node)
1361 : 0 : return error_mark_node;
1362 : :
1363 : 4162 : bool ok = false;
1364 : 4162 : tree susp_return_type = TREE_TYPE (TREE_TYPE (awsp_func));
1365 : 4162 : if (same_type_p (susp_return_type, void_type_node))
1366 : : ok = true;
1367 : 167 : else if (same_type_p (susp_return_type, boolean_type_node))
1368 : : ok = true;
1369 : 117 : else if (TREE_CODE (susp_return_type) == RECORD_TYPE
1370 : 117 : && CLASS_TYPE_P (susp_return_type)
1371 : 234 : && CLASSTYPE_TEMPLATE_INFO (susp_return_type))
1372 : : {
1373 : 114 : tree tt = CLASSTYPE_TI_TEMPLATE (susp_return_type);
1374 : 114 : if (tt == coro_handle_templ)
1375 : : ok = true;
1376 : : }
1377 : :
1378 : : if (!ok)
1379 : : {
1380 : 3 : error_at (loc, "%<await_suspend%> must return %<void%>, %<bool%> or"
1381 : : " a coroutine handle");
1382 : 3 : return error_mark_node;
1383 : : }
1384 : :
1385 : : /* Finally, the type of e.await_resume() is the co_await's type. */
1386 : 4159 : tree awrs_func = NULL_TREE;
1387 : 4159 : tree awrs_call
1388 : 4159 : = build_new_method_call (e_proxy, awrs_meth, NULL, NULL_TREE, LOOKUP_NORMAL,
1389 : : &awrs_func, tf_warning_or_error);
1390 : :
1391 : 4159 : if (!awrs_func || !awrs_call || awrs_call == error_mark_node)
1392 : 0 : return error_mark_node;
1393 : :
1394 : 4159 : if (flag_exceptions && suspend_kind == FINAL_SUSPEND_POINT)
1395 : : {
1396 : 1462 : if (coro_diagnose_throwing_fn (awrd_func))
1397 : 3 : return error_mark_node;
1398 : 1459 : if (coro_diagnose_throwing_fn (awsp_func))
1399 : 3 : return error_mark_node;
1400 : 1456 : if (coro_diagnose_throwing_fn (awrs_func))
1401 : 3 : return error_mark_node;
1402 : 1453 : if (tree dummy = cxx_maybe_build_cleanup (e_var, tf_none))
1403 : : {
1404 : 694 : if (CONVERT_EXPR_P (dummy))
1405 : 0 : dummy = TREE_OPERAND (dummy, 0);
1406 : 694 : dummy = TREE_OPERAND (CALL_EXPR_FN (dummy), 0);
1407 : 694 : if (coro_diagnose_throwing_fn (dummy))
1408 : 3 : return error_mark_node;
1409 : : }
1410 : : }
1411 : :
1412 : : /* We now have three call expressions, in terms of the promise, handle and
1413 : : 'e' proxy expression. Save them in the await expression for later
1414 : : expansion. */
1415 : :
1416 : 4147 : tree awaiter_calls = make_tree_vec (3);
1417 : 4147 : TREE_VEC_ELT (awaiter_calls, 0) = awrd_call; /* await_ready(). */
1418 : 4147 : TREE_VEC_ELT (awaiter_calls, 1) = awsp_call; /* await_suspend(). */
1419 : 4147 : tree te = NULL_TREE;
1420 : 4147 : if (TREE_CODE (awrs_call) == TARGET_EXPR)
1421 : : {
1422 : 36 : te = awrs_call;
1423 : 36 : awrs_call = TARGET_EXPR_INITIAL (awrs_call);
1424 : : }
1425 : 4147 : TREE_VEC_ELT (awaiter_calls, 2) = awrs_call; /* await_resume(). */
1426 : :
1427 : 4147 : if (e_var)
1428 : 4094 : e_proxy = e_var;
1429 : :
1430 : 4147 : tree awrs_type = TREE_TYPE (TREE_TYPE (awrs_func));
1431 : 8294 : tree suspend_kind_cst = build_int_cst (integer_type_node,
1432 : 4147 : (int) suspend_kind);
1433 : 4147 : tree await_expr = build5_loc (loc, CO_AWAIT_EXPR,
1434 : : awrs_type,
1435 : : a, e_proxy, o, awaiter_calls,
1436 : : suspend_kind_cst);
1437 : 4147 : TREE_SIDE_EFFECTS (await_expr) = true;
1438 : 4147 : if (te)
1439 : : {
1440 : 36 : TREE_OPERAND (te, 1) = await_expr;
1441 : 36 : TREE_SIDE_EFFECTS (te) = true;
1442 : 36 : await_expr = te;
1443 : : }
1444 : 4147 : SET_EXPR_LOCATION (await_expr, loc);
1445 : :
1446 : 4147 : if (processing_template_decl)
1447 : 39 : return build_template_co_await_expr (loc, awrs_type, orig_operand,
1448 : 39 : suspend_kind_cst);
1449 : 4108 : return convert_from_reference (await_expr);
1450 : : }
1451 : :
1452 : : /* Returns true iff EXPR or the TRAITS_CLASS, which should be a
1453 : : coroutine_traits instance, are dependent. In those cases, we can't decide
1454 : : what the types of our co_{await,yield,return} expressions are, so we defer
1455 : : expansion entirely. */
1456 : :
1457 : : static bool
1458 : 4347 : coro_dependent_p (tree expr, tree traits_class)
1459 : : {
1460 : 4347 : return type_dependent_expression_p (expr)
1461 : 4347 : || dependent_type_p (traits_class);
1462 : : }
1463 : :
1464 : : tree
1465 : 934 : finish_co_await_expr (location_t kw, tree expr)
1466 : : {
1467 : 934 : if (!expr || error_operand_p (expr))
1468 : 0 : return error_mark_node;
1469 : :
1470 : 934 : if (!coro_common_keyword_context_valid_p (current_function_decl, kw,
1471 : : "co_await"))
1472 : 27 : return error_mark_node;
1473 : :
1474 : : /* The current function has now become a coroutine, if it wasn't already. */
1475 : 907 : DECL_COROUTINE_P (current_function_decl) = 1;
1476 : :
1477 : : /* This function will appear to have no return statement, even if it
1478 : : is declared to return non-void (most likely). This is correct - we
1479 : : synthesize the return for the ramp in the compiler. So suppress any
1480 : : extraneous warnings during substitution. */
1481 : 907 : suppress_warning (current_function_decl, OPT_Wreturn_type);
1482 : :
1483 : : /* Prepare for coroutine transformations. */
1484 : 907 : if (!ensure_coro_initialized (kw))
1485 : 6 : return error_mark_node;
1486 : :
1487 : : /* Get our traits class. */
1488 : 901 : tree traits_class = coro_get_traits_class (current_function_decl, kw);
1489 : :
1490 : : /* Defer expansion when we are processing a template, unless the traits type
1491 : : and expression would not be dependent. In the case that the types are
1492 : : not dependent but we are processing a template declaration, we will do
1493 : : most of the computation but throw away the results (except for the
1494 : : await_resume type). Otherwise, if our co_await is type-dependent
1495 : : (i.e. the promise type or operand type is dependent), we can't do much,
1496 : : and just return early with a NULL_TREE type (indicating that we cannot
1497 : : compute the type yet). */
1498 : 901 : if (coro_dependent_p (expr, traits_class))
1499 : 109 : return build_template_co_await_expr (kw, NULL_TREE, expr,
1500 : 109 : integer_zero_node);
1501 : :
1502 : : /* We must be able to look up the "await_transform" method in the scope of
1503 : : the promise type, and obtain its return type. */
1504 : 792 : if (!coro_promise_type_found_p (current_function_decl, kw))
1505 : 3 : return error_mark_node;
1506 : :
1507 : : /* [expr.await] 3.2
1508 : : The incoming cast expression might be transformed by a promise
1509 : : 'await_transform()'. */
1510 : 789 : tree at_meth
1511 : 789 : = lookup_promise_method (current_function_decl,
1512 : : coro_await_transform_identifier, kw,
1513 : : /*musthave=*/false);
1514 : 789 : if (at_meth == error_mark_node)
1515 : : return error_mark_node;
1516 : :
1517 : 789 : tree a = expr;
1518 : 789 : if (at_meth)
1519 : : {
1520 : : /* try to build a = p.await_transform (e). */
1521 : 195 : vec<tree, va_gc> *args = make_tree_vector_single (expr);
1522 : 390 : a = build_new_method_call (get_coroutine_promise_proxy (
1523 : : current_function_decl),
1524 : : at_meth, &args, NULL_TREE, LOOKUP_NORMAL,
1525 : : NULL, tf_warning_or_error);
1526 : :
1527 : : /* As I read the section.
1528 : : We saw an await_transform method, so it's mandatory that we replace
1529 : : expr with p.await_transform (expr), therefore if the method call fails
1530 : : (presumably, we don't have suitable arguments) then this part of the
1531 : : process fails. */
1532 : 195 : if (a == error_mark_node)
1533 : 0 : return error_mark_node;
1534 : : }
1535 : :
1536 : : /* Now we want to build co_await a. */
1537 : 789 : return build_co_await (kw, a, CO_AWAIT_SUSPEND_POINT, expr);
1538 : : }
1539 : :
1540 : : /* Take the EXPR given and attempt to build:
1541 : : co_await p.yield_value (expr);
1542 : : per [expr.yield] para 1. */
1543 : :
1544 : : tree
1545 : 1858 : finish_co_yield_expr (location_t kw, tree expr)
1546 : : {
1547 : 1858 : if (!expr || error_operand_p (expr))
1548 : 0 : return error_mark_node;
1549 : :
1550 : : /* Check the general requirements and simple syntax errors. */
1551 : 1858 : if (!coro_common_keyword_context_valid_p (current_function_decl, kw,
1552 : : "co_yield"))
1553 : 27 : return error_mark_node;
1554 : :
1555 : : /* The current function has now become a coroutine, if it wasn't already. */
1556 : 1831 : DECL_COROUTINE_P (current_function_decl) = 1;
1557 : :
1558 : : /* This function will appear to have no return statement, even if it
1559 : : is declared to return non-void (most likely). This is correct - we
1560 : : synthesize the return for the ramp in the compiler. So suppress any
1561 : : extraneous warnings during substitution. */
1562 : 1831 : suppress_warning (current_function_decl, OPT_Wreturn_type);
1563 : :
1564 : : /* Prepare for coroutine transformations. */
1565 : 1831 : if (!ensure_coro_initialized (kw))
1566 : 12 : return error_mark_node;
1567 : :
1568 : : /* Get our traits class. */
1569 : 1819 : tree traits_class = coro_get_traits_class (current_function_decl, kw);
1570 : :
1571 : : /* Defer expansion when we are processing a template; see note in
1572 : : finish_co_await_expr. Also note that a yield is equivalent to
1573 : :
1574 : : co_await p.yield_value(EXPR)
1575 : :
1576 : : If either p or EXPR are type-dependent, then the whole expression is
1577 : : certainly type-dependent, and we can't proceed. */
1578 : 1819 : if (coro_dependent_p (expr, traits_class))
1579 : 1410 : return build2_loc (kw, CO_YIELD_EXPR, NULL_TREE, expr, NULL_TREE);
1580 : :
1581 : 409 : if (!coro_promise_type_found_p (current_function_decl, kw))
1582 : : /* We must be able to look up the "yield_value" method in the scope of
1583 : : the promise type, and obtain its return type. */
1584 : 6 : return error_mark_node;
1585 : :
1586 : : /* [expr.yield] / 1
1587 : : Let e be the operand of the yield-expression and p be an lvalue naming
1588 : : the promise object of the enclosing coroutine, then the yield-expression
1589 : : is equivalent to the expression co_await p.yield_value(e).
1590 : : build p.yield_value(e): */
1591 : 403 : vec<tree, va_gc> *args = make_tree_vector_single (expr);
1592 : 403 : tree yield_call
1593 : 403 : = coro_build_promise_expression (current_function_decl, NULL,
1594 : : coro_yield_value_identifier, kw,
1595 : : &args, /*musthave=*/true);
1596 : 403 : release_tree_vector (args);
1597 : :
1598 : : /* Now build co_await p.yield_value (e).
1599 : : Noting that for co_yield, there is no evaluation of any potential
1600 : : promise transform_await(), so we call build_co_await directly. */
1601 : :
1602 : 403 : tree op = build_co_await (kw, yield_call, CO_YIELD_SUSPEND_POINT);
1603 : 403 : if (op != error_mark_node)
1604 : : {
1605 : 396 : if (REFERENCE_REF_P (op))
1606 : 0 : op = TREE_OPERAND (op, 0);
1607 : : /* If the await expression is wrapped in a TARGET_EXPR, then transfer
1608 : : that wrapper to the CO_YIELD_EXPR, since this is just a proxy for
1609 : : its contained await. Otherwise, just build the CO_YIELD_EXPR. */
1610 : 396 : if (TREE_CODE (op) == TARGET_EXPR)
1611 : : {
1612 : 3 : tree t = TARGET_EXPR_INITIAL (op);
1613 : 3 : t = build2_loc (kw, CO_YIELD_EXPR, TREE_TYPE (t), expr, t);
1614 : 3 : TARGET_EXPR_INITIAL (op) = t;
1615 : : }
1616 : : else
1617 : 393 : op = build2_loc (kw, CO_YIELD_EXPR, TREE_TYPE (op), expr, op);
1618 : 396 : TREE_SIDE_EFFECTS (op) = 1;
1619 : 396 : op = convert_from_reference (op);
1620 : : }
1621 : :
1622 : : return op;
1623 : : }
1624 : :
1625 : : /* Check and build a co_return statement.
1626 : : First that it's valid to have a co_return keyword here.
1627 : : If it is, then check and build the p.return_{void(),value(expr)}.
1628 : : These are built against a proxy for the promise, which will be filled
1629 : : in with the actual frame version when the function is transformed. */
1630 : :
1631 : : tree
1632 : 1678 : finish_co_return_stmt (location_t kw, tree expr)
1633 : : {
1634 : 1678 : if (expr)
1635 : 1205 : STRIP_ANY_LOCATION_WRAPPER (expr);
1636 : :
1637 : 1678 : if (error_operand_p (expr))
1638 : 0 : return error_mark_node;
1639 : :
1640 : : /* If it fails the following test, the function is not permitted to be a
1641 : : coroutine, so the co_return statement is erroneous. */
1642 : 1678 : if (!coro_common_keyword_context_valid_p (current_function_decl, kw,
1643 : : "co_return"))
1644 : 21 : return error_mark_node;
1645 : :
1646 : : /* The current function has now become a coroutine, if it wasn't
1647 : : already. */
1648 : 1657 : DECL_COROUTINE_P (current_function_decl) = 1;
1649 : :
1650 : : /* This function will appear to have no return statement, even if it
1651 : : is declared to return non-void (most likely). This is correct - we
1652 : : synthesize the return for the ramp in the compiler. So suppress any
1653 : : extraneous warnings during substitution. */
1654 : 1657 : suppress_warning (current_function_decl, OPT_Wreturn_type);
1655 : :
1656 : : /* Prepare for coroutine transformations. */
1657 : 1657 : if (!ensure_coro_initialized (kw))
1658 : 30 : return error_mark_node;
1659 : :
1660 : : /* Get our traits class. */
1661 : 1627 : tree traits_class = coro_get_traits_class (current_function_decl, kw);
1662 : :
1663 : 1627 : if (processing_template_decl
1664 : 1627 : && check_for_bare_parameter_packs (expr))
1665 : 0 : return error_mark_node;
1666 : :
1667 : : /* Defer expansion when we must and are processing a template; see note in
1668 : : finish_co_await_expr. */
1669 : 1627 : if (coro_dependent_p (expr, traits_class))
1670 : : {
1671 : : /* co_return expressions are always void type, regardless of the
1672 : : expression type. */
1673 : 154 : expr = build2_loc (kw, CO_RETURN_EXPR, void_type_node,
1674 : : expr, NULL_TREE);
1675 : 154 : expr = maybe_cleanup_point_expr_void (expr);
1676 : 154 : return add_stmt (expr);
1677 : : }
1678 : :
1679 : 1473 : if (!coro_promise_type_found_p (current_function_decl, kw))
1680 : 18 : return error_mark_node;
1681 : :
1682 : : /* Suppress -Wreturn-type for co_return, we need to check indirectly
1683 : : whether the promise type has a suitable return_void/return_value. */
1684 : 1455 : suppress_warning (current_function_decl, OPT_Wreturn_type);
1685 : :
1686 : 1455 : if (!processing_template_decl && warn_sequence_point)
1687 : 7 : verify_sequence_points (expr);
1688 : :
1689 : 1455 : if (expr)
1690 : : {
1691 : : /* If we had an id-expression obfuscated by force_paren_expr, we need
1692 : : to undo it so we can try to treat it as an rvalue below. */
1693 : 1039 : expr = maybe_undo_parenthesized_ref (expr);
1694 : :
1695 : 1039 : if (error_operand_p (expr))
1696 : 0 : return error_mark_node;
1697 : : }
1698 : :
1699 : : /* If the promise object doesn't have the correct return call then
1700 : : there's a mis-match between the co_return <expr> and this. */
1701 : 416 : tree co_ret_call = error_mark_node;
1702 : 1039 : if (expr == NULL_TREE || VOID_TYPE_P (TREE_TYPE (expr)))
1703 : 426 : co_ret_call
1704 : 426 : = get_coroutine_return_void_expr (current_function_decl, kw, true);
1705 : : else
1706 : : {
1707 : : /* [class.copy.elision] / 3.
1708 : : An implicitly movable entity is a variable of automatic storage
1709 : : duration that is either a non-volatile object or an rvalue reference
1710 : : to a non-volatile object type. For such objects in the context of
1711 : : the co_return, the overload resolution should be carried out first
1712 : : treating the object as an rvalue, if that fails, then we fall back
1713 : : to regular overload resolution. */
1714 : :
1715 : 1029 : tree arg = expr;
1716 : 1029 : if (tree moved = treat_lvalue_as_rvalue_p (expr, /*return*/true))
1717 : 247 : arg = moved;
1718 : :
1719 : 1029 : releasing_vec args = make_tree_vector_single (arg);
1720 : 1029 : co_ret_call
1721 : 1029 : = coro_build_promise_expression (current_function_decl, NULL,
1722 : : coro_return_value_identifier, kw,
1723 : : &args, /*musthave=*/true);
1724 : 1029 : }
1725 : :
1726 : : /* Makes no sense for a co-routine really. */
1727 : 1455 : if (TREE_THIS_VOLATILE (current_function_decl))
1728 : 0 : warning_at (kw, 0,
1729 : : "function declared %<noreturn%> has a"
1730 : : " %<co_return%> statement");
1731 : :
1732 : 1455 : expr = build2_loc (kw, CO_RETURN_EXPR, void_type_node, expr, co_ret_call);
1733 : 1455 : expr = maybe_cleanup_point_expr_void (expr);
1734 : 1455 : return add_stmt (expr);
1735 : : }
1736 : :
1737 : : /* We need to validate the arguments to __builtin_coro_promise, since the
1738 : : second two must be constant, and the builtins machinery doesn't seem to
1739 : : deal with that properly. */
1740 : :
1741 : : tree
1742 : 2820696 : coro_validate_builtin_call (tree call, tsubst_flags_t)
1743 : : {
1744 : 2820696 : tree fn = TREE_OPERAND (CALL_EXPR_FN (call), 0);
1745 : :
1746 : 2820696 : gcc_checking_assert (DECL_BUILT_IN_CLASS (fn) == BUILT_IN_NORMAL);
1747 : 2820696 : switch (DECL_FUNCTION_CODE (fn))
1748 : : {
1749 : : default:
1750 : : return call;
1751 : :
1752 : 9070 : case BUILT_IN_CORO_PROMISE:
1753 : 9070 : {
1754 : : /* Argument 0 is already checked by the normal built-in machinery
1755 : : Argument 1 must be a constant of size type. It probably makes
1756 : : little sense if it's not a power of 2, but that isn't specified
1757 : : formally. */
1758 : 9070 : tree arg = CALL_EXPR_ARG (call, 1);
1759 : 9070 : location_t loc = EXPR_LOCATION (arg);
1760 : :
1761 : : /* We expect alignof expressions in templates. */
1762 : 9070 : if (TREE_CODE (arg) == ALIGNOF_EXPR)
1763 : : ;
1764 : 1830 : else if (!TREE_CONSTANT (arg))
1765 : : {
1766 : 0 : error_at (loc, "the align argument to %<__builtin_coro_promise%>"
1767 : : " must be a constant");
1768 : 0 : return error_mark_node;
1769 : : }
1770 : : /* Argument 2 is the direction - to / from handle address to promise
1771 : : address. */
1772 : 9070 : arg = CALL_EXPR_ARG (call, 2);
1773 : 9070 : loc = EXPR_LOCATION (arg);
1774 : 9070 : if (!TREE_CONSTANT (arg))
1775 : : {
1776 : 0 : error_at (loc, "the direction argument to"
1777 : : " %<__builtin_coro_promise%> must be a constant");
1778 : 0 : return error_mark_node;
1779 : : }
1780 : : return call;
1781 : : break;
1782 : : }
1783 : : }
1784 : : }
1785 : :
1786 : : /* ================= Morph and Expand. =================
1787 : :
1788 : : The entry point here is morph_fn_to_coro () which is called from
1789 : : finish_function () when we have completed any template expansion.
1790 : :
1791 : : This is preceded by helper functions that implement the phases below.
1792 : :
1793 : : The process proceeds in four phases.
1794 : :
1795 : : A Initial framing.
1796 : : The user's function body is wrapped in the initial and final suspend
1797 : : points and we begin building the coroutine frame.
1798 : : We build empty decls for the actor and destroyer functions at this
1799 : : time too.
1800 : : When exceptions are enabled, the user's function body will also be
1801 : : wrapped in a try-catch block with the catch invoking the promise
1802 : : class 'unhandled_exception' method.
1803 : :
1804 : : B Analysis.
1805 : : The user's function body is analyzed to determine the suspend points,
1806 : : if any, and to capture local variables that might persist across such
1807 : : suspensions. In most cases, it is not necessary to capture compiler
1808 : : temporaries, since the tree-lowering nests the suspensions correctly.
1809 : : However, in the case of a captured reference, there is a lifetime
1810 : : extension to the end of the full expression - which can mean across a
1811 : : suspend point in which case it must be promoted to a frame variable.
1812 : :
1813 : : At the conclusion of analysis, we have a conservative frame layout and
1814 : : maps of the local variables to their frame entry points.
1815 : :
1816 : : C Build the ramp function.
1817 : : Carry out the allocation for the coroutine frame (NOTE; the actual size
1818 : : computation is deferred until late in the middle end to allow for future
1819 : : optimizations that will be allowed to elide unused frame entries).
1820 : : We build the return object.
1821 : :
1822 : : D Build and expand the actor and destroyer function bodies.
1823 : : The destroyer is a trivial shim that sets a bit to indicate that the
1824 : : destroy dispatcher should be used and then calls into the actor.
1825 : :
1826 : : The actor function is the implementation of the user's state machine.
1827 : : The current suspend point is noted in an index.
1828 : : Each suspend point is encoded as a pair of internal functions, one in
1829 : : the relevant dispatcher, and one representing the suspend point.
1830 : :
1831 : : During this process, the user's local variables and the proxies for the
1832 : : self-handle and the promise class instance are re-written to their
1833 : : coroutine frame equivalents.
1834 : :
1835 : : The complete bodies for the ramp, actor and destroy function are passed
1836 : : back to finish_function for folding and gimplification. */
1837 : :
1838 : : /* Helper to build a coroutine state frame access expression
1839 : : CORO_FP is a frame pointer
1840 : : MEMBER_ID is an identifier for a frame field
1841 : : PRESERVE_REF is true, the expression returned will have REFERENCE_TYPE if
1842 : : the MEMBER does.
1843 : : COMPLAIN is passed to the underlying functions. */
1844 : :
1845 : : static tree
1846 : 34375 : coro_build_frame_access_expr (tree coro_ref, tree member_id, bool preserve_ref,
1847 : : tsubst_flags_t complain)
1848 : : {
1849 : 34375 : gcc_checking_assert (INDIRECT_REF_P (coro_ref));
1850 : 34375 : tree fr_type = TREE_TYPE (coro_ref);
1851 : 34375 : tree mb = lookup_member (fr_type, member_id, /*protect=*/1, /*want_type=*/0,
1852 : : complain);
1853 : 34375 : if (!mb || mb == error_mark_node)
1854 : 0 : return error_mark_node;
1855 : 34375 : tree expr
1856 : 34375 : = build_class_member_access_expr (coro_ref, mb, NULL_TREE,
1857 : : preserve_ref, complain);
1858 : 34375 : return expr;
1859 : : }
1860 : :
1861 : : /* Helpers to build an artificial var, with location LOC, NAME and TYPE, in
1862 : : CTX, and with initializer INIT. */
1863 : :
1864 : : static tree
1865 : 22726 : coro_build_artificial_var (location_t loc, tree name, tree type, tree ctx,
1866 : : tree init)
1867 : : {
1868 : 22726 : tree res = build_lang_decl (VAR_DECL, name, type);
1869 : 22726 : DECL_SOURCE_LOCATION (res) = loc;
1870 : 22726 : DECL_CONTEXT (res) = ctx;
1871 : 22726 : DECL_ARTIFICIAL (res) = true;
1872 : 22726 : DECL_INITIAL (res) = init;
1873 : 22726 : return res;
1874 : : }
1875 : :
1876 : : /* As above, except allowing the name to be a string. */
1877 : :
1878 : : static tree
1879 : 4518 : coro_build_artificial_var (location_t loc, const char *name, tree type,
1880 : : tree ctx, tree init)
1881 : : {
1882 : 4518 : return coro_build_artificial_var (loc, get_identifier (name),
1883 : 4518 : type, ctx, init);
1884 : : }
1885 : :
1886 : : /* As for coro_build_artificial_var, except that we push this decl into
1887 : : the current binding scope and add the decl_expr. */
1888 : :
1889 : : static tree
1890 : 2989 : coro_build_and_push_artificial_var (location_t loc, const char *name,
1891 : : tree type, tree ctx, tree init)
1892 : : {
1893 : 2989 : tree v = coro_build_artificial_var (loc, name, type, ctx, init);
1894 : 2989 : v = pushdecl (v);
1895 : 2989 : add_decl_expr (v);
1896 : 2989 : return v;
1897 : : }
1898 : :
1899 : : /* Build a var NAME of TYPE in CTX and with INIT; add a DECL_VALUE_EXPR that
1900 : : refers to BASE.FIELD. */
1901 : :
1902 : : static tree
1903 : 9059 : coro_build_artificial_var_with_dve (location_t loc, tree name, tree type,
1904 : : tree ctx, tree init, tree base,
1905 : : tree field = NULL_TREE)
1906 : : {
1907 : 9059 : tree v = coro_build_artificial_var (loc, name, type, ctx, init);
1908 : 9059 : if (field == NULL_TREE)
1909 : 9059 : field = name;
1910 : 9059 : tree dve = coro_build_frame_access_expr (base, field, true,
1911 : : tf_warning_or_error);
1912 : 9059 : SET_DECL_VALUE_EXPR (v, dve);
1913 : 9059 : DECL_HAS_VALUE_EXPR_P (v) = true;
1914 : 9059 : return v;
1915 : : }
1916 : :
1917 : : /* As for coro_build_artificial_var_with_dve, but push into the current binding
1918 : : scope and add the decl_expr. */
1919 : :
1920 : : static tree
1921 : 9059 : coro_build_and_push_artificial_var_with_dve (location_t loc, tree name,
1922 : : tree type, tree ctx, tree init,
1923 : : tree base, tree field = NULL_TREE)
1924 : : {
1925 : 9059 : tree v = coro_build_artificial_var_with_dve (loc, name, type, ctx, init,
1926 : : base, field);
1927 : 9059 : v = pushdecl (v);
1928 : 9059 : add_decl_expr (v);
1929 : 9059 : return v;
1930 : : }
1931 : :
1932 : : /* 2. Create a named label in the specified context. */
1933 : :
1934 : : static tree
1935 : 17211 : create_named_label_with_ctx (location_t loc, const char *name, tree ctx)
1936 : : {
1937 : 17211 : tree lab_id = get_identifier (name);
1938 : 17211 : tree lab = define_label (loc, lab_id);
1939 : 17211 : DECL_CONTEXT (lab) = ctx;
1940 : 17211 : DECL_ARTIFICIAL (lab) = true;
1941 : 17211 : TREE_USED (lab) = true;
1942 : 17211 : return lab;
1943 : : }
1944 : :
1945 : : struct proxy_replace
1946 : : {
1947 : : tree from, to;
1948 : : };
1949 : :
1950 : : static tree
1951 : 10903 : replace_proxy (tree *here, int *do_subtree, void *d)
1952 : : {
1953 : 10903 : proxy_replace *data = (proxy_replace *) d;
1954 : :
1955 : 10903 : if (*here == data->from)
1956 : : {
1957 : 198 : *here = data->to;
1958 : 198 : *do_subtree = 0;
1959 : : }
1960 : : else
1961 : 10705 : *do_subtree = 1;
1962 : 10903 : return NULL_TREE;
1963 : : }
1964 : :
1965 : : /* Support for expansion of co_await statements. */
1966 : :
1967 : : struct coro_aw_data
1968 : : {
1969 : : tree actor_fn; /* Decl for context. */
1970 : : tree coro_fp; /* Frame pointer var. */
1971 : : tree resume_idx; /* This is the index var in the frame. */
1972 : : tree i_a_r_c; /* initial suspend await_resume() was called if true. */
1973 : : tree self_h; /* This is a handle to the current coro (frame var). */
1974 : : tree cleanup; /* This is where to go once we complete local destroy. */
1975 : : tree cororet; /* This is where to go if we suspend. */
1976 : : tree corocont; /* This is where to go if we continue. */
1977 : : tree dispatch; /* This is where we go if we restart the dispatch. */
1978 : : tree conthand; /* This is the handle for a continuation. */
1979 : : unsigned index; /* This is our current resume index. */
1980 : : };
1981 : :
1982 : : /* Lightweight search for the first await expression in tree-walk order.
1983 : : returns:
1984 : : The first await expression found in STMT.
1985 : : NULL_TREE if there are none.
1986 : : So can be used to determine if the statement needs to be processed for
1987 : : awaits. */
1988 : :
1989 : : static tree
1990 : 356290 : co_await_find_in_subtree (tree *stmt, int *, void *d)
1991 : : {
1992 : 356290 : tree **p = (tree **) d;
1993 : 356290 : if (TREE_CODE (*stmt) == CO_AWAIT_EXPR)
1994 : : {
1995 : 4054 : *p = stmt;
1996 : 4054 : return *stmt;
1997 : : }
1998 : : return NULL_TREE;
1999 : : }
2000 : :
2001 : : /* Starting with a statement:
2002 : :
2003 : : stmt => some tree containing one or more await expressions.
2004 : :
2005 : : We replace the statement with:
2006 : : <STATEMENT_LIST> {
2007 : : initialize awaitable
2008 : : if (!ready)
2009 : : {
2010 : : suspension context.
2011 : : }
2012 : : resume:
2013 : : revised statement with one await expression rewritten to its
2014 : : await_resume() return value.
2015 : : }
2016 : :
2017 : : We then recurse into the initializer and the revised statement
2018 : : repeating this replacement until there are no more await expressions
2019 : : in either. */
2020 : :
2021 : : static tree *
2022 : 4054 : expand_one_await_expression (tree *expr, tree *await_expr, void *d)
2023 : : {
2024 : 4054 : coro_aw_data *data = (coro_aw_data *) d;
2025 : :
2026 : 4054 : tree saved_statement = *expr;
2027 : 4054 : tree saved_co_await = *await_expr;
2028 : :
2029 : 4054 : tree actor = data->actor_fn;
2030 : 4054 : location_t loc = EXPR_LOCATION (*expr);
2031 : 4054 : tree var = TREE_OPERAND (saved_co_await, 1); /* frame slot. */
2032 : 4054 : tree init_expr = TREE_OPERAND (saved_co_await, 2); /* initializer. */
2033 : 4054 : tree awaiter_calls = TREE_OPERAND (saved_co_await, 3);
2034 : :
2035 : 4054 : tree source = TREE_OPERAND (saved_co_await, 4);
2036 : 4054 : bool is_final
2037 : 4054 : = (source && TREE_INT_CST_LOW (source) == (int) FINAL_SUSPEND_POINT);
2038 : 4054 : bool is_initial
2039 : 4054 : = (source && TREE_INT_CST_LOW (source) == (int) INITIAL_SUSPEND_POINT);
2040 : :
2041 : : /* Build labels for the destinations of the control flow when we are resuming
2042 : : or destroying. */
2043 : 4054 : int resume_point = data->index;
2044 : 4054 : char *buf = xasprintf ("destroy.%d", resume_point);
2045 : 4054 : tree destroy_label = create_named_label_with_ctx (loc, buf, actor);
2046 : 4054 : free (buf);
2047 : 4054 : buf = xasprintf ("resume.%d", resume_point);
2048 : 4054 : tree resume_label = create_named_label_with_ctx (loc, buf, actor);
2049 : 4054 : free (buf);
2050 : :
2051 : : /* This will contain our expanded expression and replace the original
2052 : : expression. */
2053 : 4054 : tree stmt_list = push_stmt_list ();
2054 : 4054 : tree *await_init = NULL;
2055 : :
2056 : 4054 : bool needs_dtor = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (var));
2057 : 4054 : if (!init_expr)
2058 : : needs_dtor = false; /* No need, the var's lifetime is managed elsewhere. */
2059 : : else
2060 : : {
2061 : 0 : finish_expr_stmt (init_expr);
2062 : : /* We have an initializer, which might itself contain await exprs. */
2063 : 0 : await_init = tsi_stmt_ptr (tsi_last (stmt_list));
2064 : : }
2065 : :
2066 : : /* Use the await_ready() call to test if we need to suspend. */
2067 : 4054 : tree ready_cond = TREE_VEC_ELT (awaiter_calls, 0); /* await_ready(). */
2068 : :
2069 : : /* We will resume (or continue) at the following index. */
2070 : 4054 : tree resume_idx = build_int_cst (short_unsigned_type_node, data->index);
2071 : 4054 : tree r = cp_build_init_expr (data->resume_idx, resume_idx);
2072 : 4054 : finish_expr_stmt (r);
2073 : :
2074 : : /* Convert to bool, if necessary. */
2075 : 4054 : if (TREE_CODE (TREE_TYPE (ready_cond)) != BOOLEAN_TYPE)
2076 : 6 : ready_cond = cp_convert (boolean_type_node, ready_cond,
2077 : : tf_warning_or_error);
2078 : 4054 : tree susp_if = begin_if_stmt ();
2079 : : /* Be aggressive in folding here, since there are a significant number of
2080 : : cases where the ready condition is constant. */
2081 : 4054 : ready_cond = invert_truthvalue_loc (loc, ready_cond);
2082 : 4054 : finish_if_stmt_cond (ready_cond, susp_if);
2083 : :
2084 : : /* Find out what we have to do with the awaiter's suspend method.
2085 : : [expr.await]
2086 : : (5.1) If the result of await-ready is false, the coroutine is considered
2087 : : suspended. Then:
2088 : : (5.1.1) If the type of await-suspend is std::coroutine_handle<Z>,
2089 : : await-suspend.resume() is evaluated.
2090 : : (5.1.2) if the type of await-suspend is bool, await-suspend is evaluated,
2091 : : and the coroutine is resumed if the result is false.
2092 : : (5.1.3) Otherwise, await-suspend is evaluated. */
2093 : :
2094 : 4054 : tree suspend = TREE_VEC_ELT (awaiter_calls, 1); /* await_suspend(). */
2095 : 4054 : tree susp_type = TREE_TYPE (suspend);
2096 : :
2097 : 4054 : bool is_cont = false;
2098 : : /* NOTE: final suspend can't resume; the "resume" label in that case
2099 : : corresponds to implicit destruction. */
2100 : 4054 : if (VOID_TYPE_P (susp_type))
2101 : : /* Void return - just proceed to suspend. */
2102 : 3905 : finish_expr_stmt (suspend);
2103 : 149 : else if (TREE_CODE (susp_type) == BOOLEAN_TYPE)
2104 : : {
2105 : : /* Boolean return, "continue" if the call returns false. */
2106 : 35 : tree restart_if = begin_if_stmt ();
2107 : 35 : suspend = invert_truthvalue_loc (loc, suspend);
2108 : 35 : finish_if_stmt_cond (suspend, restart_if);
2109 : : /* Resume - so restart the dispatcher, since we do not know if this
2110 : : coroutine was already resumed from within await_suspend. We must
2111 : : exit this scope without cleanups. */
2112 : 35 : r = build_call_expr_internal_loc (loc, IFN_CO_SUSPN, void_type_node, 1,
2113 : : build_address (data->dispatch));
2114 : : /* This will eventually expand to 'goto coro.restart.dispatch'. */
2115 : 35 : finish_expr_stmt (r);
2116 : 35 : finish_then_clause (restart_if);
2117 : 35 : finish_if_stmt (restart_if);
2118 : : }
2119 : : else
2120 : : {
2121 : : /* Handle return, save it to the continuation. */
2122 : 114 : r = suspend;
2123 : 114 : if (!same_type_ignoring_top_level_qualifiers_p (susp_type,
2124 : : void_coro_handle_type))
2125 : 16 : r = build1_loc (loc, VIEW_CONVERT_EXPR, void_coro_handle_type, r);
2126 : 114 : r = cp_build_init_expr (loc, data->conthand, r);
2127 : 114 : finish_expr_stmt (r);
2128 : 114 : is_cont = true;
2129 : : }
2130 : :
2131 : 4054 : tree d_l = build_address (destroy_label);
2132 : 4054 : tree r_l = build_address (resume_label);
2133 : 4054 : tree susp = build_address (data->cororet);
2134 : 4054 : tree cont = build_address (data->corocont);
2135 : 6657 : tree final_susp = build_int_cst (integer_type_node, is_final ? 1 : 0);
2136 : :
2137 : 4054 : resume_idx = build_int_cst (integer_type_node, data->index);
2138 : :
2139 : 4054 : tree sw = begin_switch_stmt ();
2140 : :
2141 : 4054 : r = build_call_expr_internal_loc (loc, IFN_CO_YIELD, integer_type_node, 5,
2142 : : resume_idx, final_susp, r_l, d_l,
2143 : : data->coro_fp);
2144 : 4054 : finish_switch_cond (r, sw);
2145 : 4054 : finish_case_label (loc, integer_zero_node, NULL_TREE); /* case 0: */
2146 : : /* Implement the suspend, a scope exit without clean ups. */
2147 : 7994 : r = build_call_expr_internal_loc (loc, IFN_CO_SUSPN, void_type_node, 1,
2148 : : is_cont ? cont : susp);
2149 : 4054 : finish_expr_stmt (r); /* This will eventually expand to 'goto return'. */
2150 : 4054 : finish_case_label (loc, integer_one_node, NULL_TREE); /* case 1: */
2151 : 4054 : add_stmt (build_stmt (loc, GOTO_EXPR, resume_label)); /* goto resume; */
2152 : 4054 : finish_case_label (loc, NULL_TREE, NULL_TREE); /* default:; */
2153 : 4054 : add_stmt (build_stmt (loc, GOTO_EXPR, destroy_label)); /* goto destroy; */
2154 : :
2155 : 4054 : finish_switch_stmt (sw);
2156 : 4054 : add_stmt (build_stmt (loc, LABEL_EXPR, destroy_label));
2157 : 4054 : if (needs_dtor)
2158 : 0 : finish_expr_stmt (build_cleanup (var));
2159 : 4054 : add_stmt (build_stmt (loc, GOTO_EXPR, data->cleanup));
2160 : :
2161 : 4054 : finish_then_clause (susp_if);
2162 : 4054 : finish_if_stmt (susp_if);
2163 : :
2164 : : /* Resume point. */
2165 : 4054 : add_stmt (build_stmt (loc, LABEL_EXPR, resume_label));
2166 : :
2167 : 4054 : if (is_initial && data->i_a_r_c)
2168 : : {
2169 : 1456 : r = cp_build_modify_expr (loc, data->i_a_r_c, NOP_EXPR, boolean_true_node,
2170 : : tf_warning_or_error);
2171 : 1456 : finish_expr_stmt (r);
2172 : : }
2173 : :
2174 : : /* This will produce the value (if one is provided) from the co_await
2175 : : expression. */
2176 : 4054 : tree resume_call = TREE_VEC_ELT (awaiter_calls, 2); /* await_resume(). */
2177 : 4054 : if (REFERENCE_REF_P (resume_call))
2178 : : /* Sink to await_resume call_expr. */
2179 : 71 : resume_call = TREE_OPERAND (resume_call, 0);
2180 : :
2181 : 4054 : *await_expr = resume_call; /* Replace the co_await expr with its result. */
2182 : 4054 : append_to_statement_list_force (saved_statement, &stmt_list);
2183 : : /* Get a pointer to the revised statement. */
2184 : 4054 : tree *revised = tsi_stmt_ptr (tsi_last (stmt_list));
2185 : 4054 : if (needs_dtor)
2186 : 0 : finish_expr_stmt (build_cleanup (var));
2187 : 4054 : data->index += 2;
2188 : :
2189 : : /* Replace the original expression with the expansion. */
2190 : 4054 : *expr = pop_stmt_list (stmt_list);
2191 : :
2192 : : /* Now, if the awaitable had an initializer, expand any awaits that might
2193 : : be embedded in it. */
2194 : 4054 : tree *aw_expr_ptr;
2195 : 4054 : if (await_init &&
2196 : 0 : cp_walk_tree (await_init, co_await_find_in_subtree, &aw_expr_ptr, NULL))
2197 : 0 : expand_one_await_expression (await_init, aw_expr_ptr, d);
2198 : :
2199 : : /* Expand any more await expressions in the original statement. */
2200 : 4054 : if (cp_walk_tree (revised, co_await_find_in_subtree, &aw_expr_ptr, NULL))
2201 : 14 : expand_one_await_expression (revised, aw_expr_ptr, d);
2202 : :
2203 : 4054 : return NULL;
2204 : : }
2205 : :
2206 : : /* Check to see if a statement contains at least one await expression, if
2207 : : so, then process that. */
2208 : :
2209 : : static tree
2210 : 46757 : process_one_statement (tree *stmt, void *d)
2211 : : {
2212 : 46757 : tree *aw_expr_ptr;
2213 : 46757 : if (cp_walk_tree (stmt, co_await_find_in_subtree, &aw_expr_ptr, NULL))
2214 : 4040 : expand_one_await_expression (stmt, aw_expr_ptr, d);
2215 : 46757 : return NULL_TREE;
2216 : : }
2217 : :
2218 : : static tree
2219 : 355991 : await_statement_expander (tree *stmt, int *do_subtree, void *d)
2220 : : {
2221 : 355991 : tree res = NULL_TREE;
2222 : :
2223 : : /* Process a statement at a time. */
2224 : 355991 : if (STATEMENT_CLASS_P (*stmt)
2225 : 278954 : || TREE_CODE (*stmt) == BIND_EXPR
2226 : 271642 : || TREE_CODE (*stmt) == CLEANUP_POINT_EXPR)
2227 : : return NULL_TREE; /* Just process the sub-trees. */
2228 : 236908 : else if (TREE_CODE (*stmt) == STATEMENT_LIST)
2229 : : {
2230 : 127766 : for (tree &s : tsi_range (*stmt))
2231 : : {
2232 : 110230 : res = cp_walk_tree (&s, await_statement_expander,
2233 : : d, NULL);
2234 : 110230 : if (res)
2235 : 355991 : return res;
2236 : : }
2237 : 17536 : *do_subtree = 0; /* Done subtrees. */
2238 : : }
2239 : 219372 : else if (EXPR_P (*stmt))
2240 : : {
2241 : 46757 : process_one_statement (stmt, d);
2242 : 46757 : *do_subtree = 0; /* Done subtrees. */
2243 : : }
2244 : :
2245 : : /* Continue statement walk, where required. */
2246 : : return res;
2247 : : }
2248 : :
2249 : : struct await_xform_data
2250 : : {
2251 : : tree actor_fn; /* Decl for context. */
2252 : : tree actor_frame;
2253 : : hash_map<tree, suspend_point_info> *suspend_points;
2254 : : };
2255 : :
2256 : : /* When we built the await expressions, we didn't know the coro frame
2257 : : layout, therefore no idea where to find the promise or where to put
2258 : : the awaitables. Now we know these things, fill them in. */
2259 : :
2260 : : static tree
2261 : 4054 : transform_await_expr (tree await_expr, await_xform_data *xform)
2262 : : {
2263 : 4054 : suspend_point_info *si = xform->suspend_points->get (await_expr);
2264 : 4054 : location_t loc = EXPR_LOCATION (await_expr);
2265 : 4054 : if (!si)
2266 : : {
2267 : 0 : error_at (loc, "no suspend point info for %qD", await_expr);
2268 : 0 : return error_mark_node;
2269 : : }
2270 : :
2271 : : /* So, on entry, we have:
2272 : : in : CO_AWAIT_EXPR (a, e_proxy, o, awr_call_vector, mode)
2273 : : We no longer need a [it had diagnostic value, maybe?]
2274 : : We need to replace the e_proxy in the awr_call. */
2275 : :
2276 : : /* If we have a frame var for the awaitable, get a reference to it. */
2277 : 4054 : proxy_replace data;
2278 : 4054 : if (si->await_field_id)
2279 : : {
2280 : 0 : tree as
2281 : 0 : = coro_build_frame_access_expr (xform->actor_frame, si->await_field_id,
2282 : : true, tf_warning_or_error);
2283 : : /* Replace references to the instance proxy with the frame entry now
2284 : : computed. */
2285 : 0 : data.from = TREE_OPERAND (await_expr, 1);
2286 : 0 : data.to = as;
2287 : 0 : cp_walk_tree (&await_expr, replace_proxy, &data, NULL);
2288 : :
2289 : : /* .. and replace. */
2290 : 0 : TREE_OPERAND (await_expr, 1) = as;
2291 : : }
2292 : :
2293 : 4054 : return await_expr;
2294 : : }
2295 : :
2296 : : /* A wrapper for the transform_await_expr function so that it can be a
2297 : : callback from cp_walk_tree. */
2298 : :
2299 : : static tree
2300 : 323417 : transform_await_wrapper (tree *stmt, int *do_subtree, void *d)
2301 : : {
2302 : : /* Set actor function as new DECL_CONTEXT of label_decl. */
2303 : 323417 : struct await_xform_data *xform = (struct await_xform_data *) d;
2304 : 323417 : if (TREE_CODE (*stmt) == LABEL_DECL
2305 : 323417 : && DECL_CONTEXT (*stmt) != xform->actor_fn)
2306 : 1563 : DECL_CONTEXT (*stmt) = xform->actor_fn;
2307 : :
2308 : : /* We should have already lowered co_yields to their co_await. */
2309 : 323417 : gcc_checking_assert (TREE_CODE (*stmt) != CO_YIELD_EXPR);
2310 : 323417 : if (TREE_CODE (*stmt) != CO_AWAIT_EXPR)
2311 : : return NULL_TREE;
2312 : :
2313 : 4054 : tree await_expr = *stmt;
2314 : 4054 : *stmt = transform_await_expr (await_expr, xform);
2315 : 4054 : if (*stmt == error_mark_node)
2316 : 0 : *do_subtree = 0;
2317 : : return NULL_TREE;
2318 : : }
2319 : :
2320 : : /* For figuring out what local variable usage we have. */
2321 : : struct local_vars_transform
2322 : : {
2323 : : tree context;
2324 : : tree actor_frame;
2325 : : tree coro_frame_type;
2326 : : location_t loc;
2327 : : hash_map<tree, local_var_info> *local_var_uses;
2328 : : };
2329 : :
2330 : : static tree
2331 : 505801 : transform_local_var_uses (tree *stmt, int *do_subtree, void *d)
2332 : : {
2333 : 505801 : local_vars_transform *lvd = (local_vars_transform *) d;
2334 : :
2335 : : /* For each var in this bind expr (that has a frame id, which means it was
2336 : : accessed), build a frame reference and add it as the DECL_VALUE_EXPR. */
2337 : :
2338 : 505801 : if (TREE_CODE (*stmt) == BIND_EXPR)
2339 : : {
2340 : 7318 : tree lvar;
2341 : 24241 : for (lvar = BIND_EXPR_VARS (*stmt); lvar != NULL;
2342 : 16923 : lvar = DECL_CHAIN (lvar))
2343 : : {
2344 : 16923 : bool existed;
2345 : 16923 : local_var_info &local_var
2346 : 16923 : = lvd->local_var_uses->get_or_insert (lvar, &existed);
2347 : 16923 : gcc_checking_assert (existed);
2348 : :
2349 : : /* Re-write the variable's context to be in the actor func. */
2350 : 16923 : DECL_CONTEXT (lvar) = lvd->context;
2351 : :
2352 : : /* For capture proxies, this could include the decl value expr. */
2353 : 16923 : if (local_var.is_lambda_capture || local_var.has_value_expr_p)
2354 : 171 : continue; /* No frame entry for this. */
2355 : :
2356 : : /* TODO: implement selective generation of fields when vars are
2357 : : known not-used. */
2358 : 16807 : if (local_var.field_id == NULL_TREE)
2359 : 55 : continue; /* Wasn't used. */
2360 : 16752 : tree fld_idx
2361 : 16752 : = coro_build_frame_access_expr (lvd->actor_frame,
2362 : : local_var.field_id, true,
2363 : : tf_warning_or_error);
2364 : 16752 : local_var.field_idx = fld_idx;
2365 : 16752 : SET_DECL_VALUE_EXPR (lvar, fld_idx);
2366 : 16752 : DECL_HAS_VALUE_EXPR_P (lvar) = true;
2367 : : }
2368 : 7318 : cp_walk_tree (&BIND_EXPR_BODY (*stmt), transform_local_var_uses, d, NULL);
2369 : 7318 : *do_subtree = 0; /* We've done the body already. */
2370 : 7318 : return NULL_TREE;
2371 : : }
2372 : : return NULL_TREE;
2373 : : }
2374 : :
2375 : : /* A helper to build the frame DTOR.
2376 : : [dcl.fct.def.coroutine] / 12
2377 : : The deallocation function’s name is looked up in the scope of the promise
2378 : : type. If this lookup fails, the deallocation function’s name is looked up
2379 : : in the global scope. If deallocation function lookup finds both a usual
2380 : : deallocation function with only a pointer parameter and a usual
2381 : : deallocation function with both a pointer parameter and a size parameter,
2382 : : then the selected deallocation function shall be the one with two
2383 : : parameters. Otherwise, the selected deallocation function shall be the
2384 : : function with one parameter. If no usual deallocation function is found
2385 : : the program is ill-formed. The selected deallocation function shall be
2386 : : called with the address of the block of storage to be reclaimed as its
2387 : : first argument. If a deallocation function with a parameter of type
2388 : : std::size_t is used, the size of the block is passed as the corresponding
2389 : : argument. */
2390 : :
2391 : : static tree
2392 : : build_coroutine_frame_delete_expr (tree, tree, tree, location_t);
2393 : :
2394 : : /* The actor transform. */
2395 : :
2396 : : static void
2397 : 1511 : build_actor_fn (location_t loc, tree coro_frame_type, tree actor, tree fnbody,
2398 : : tree orig, hash_map<tree, local_var_info> *local_var_uses,
2399 : : hash_map<tree, suspend_point_info> *suspend_points,
2400 : : vec<tree> *param_dtor_list,
2401 : : tree resume_idx_var, unsigned body_count, tree frame_size,
2402 : : bool inline_p)
2403 : : {
2404 : 1511 : verify_stmt_tree (fnbody);
2405 : : /* Some things we inherit from the original function. */
2406 : 1511 : tree promise_type = get_coroutine_promise_type (orig);
2407 : 1511 : tree promise_proxy = get_coroutine_promise_proxy (orig);
2408 : :
2409 : : /* One param, the coro frame pointer. */
2410 : 1511 : tree actor_fp = DECL_ARGUMENTS (actor);
2411 : :
2412 : 1511 : bool spf = start_preparsed_function (actor, NULL_TREE, SF_PRE_PARSED);
2413 : 1511 : gcc_checking_assert (spf);
2414 : 1511 : gcc_checking_assert (cfun && current_function_decl && TREE_STATIC (actor));
2415 : 1511 : if (flag_exceptions)
2416 : : /* We, unconditionally, add a try/catch and rethrow.
2417 : : TODO: Determine if the combination of initial suspend and the original
2418 : : body cannot throw, and elide these additions. */
2419 : 1489 : cp_function_chain->can_throw = true;
2420 : 1511 : tree stmt = begin_function_body ();
2421 : :
2422 : 1511 : tree actor_bind = build3 (BIND_EXPR, void_type_node, NULL, NULL, NULL);
2423 : 1511 : tree top_block = make_node (BLOCK);
2424 : 1511 : BIND_EXPR_BLOCK (actor_bind) = top_block;
2425 : :
2426 : 1511 : tree continuation = coro_build_artificial_var (loc, coro_actor_continue_id,
2427 : : void_coro_handle_type, actor,
2428 : : NULL_TREE);
2429 : :
2430 : 1511 : BIND_EXPR_VARS (actor_bind) = continuation;
2431 : 1511 : BLOCK_VARS (top_block) = BIND_EXPR_VARS (actor_bind) ;
2432 : :
2433 : : /* Link in the block associated with the outer scope of the re-written
2434 : : function body. */
2435 : 1511 : tree first = expr_first (fnbody);
2436 : 1511 : gcc_checking_assert (first && TREE_CODE (first) == BIND_EXPR);
2437 : 1511 : tree block = BIND_EXPR_BLOCK (first);
2438 : 1511 : gcc_checking_assert (BLOCK_SUPERCONTEXT (block) == NULL_TREE);
2439 : 1511 : gcc_checking_assert (BLOCK_CHAIN (block) == NULL_TREE);
2440 : 1511 : BLOCK_SUPERCONTEXT (block) = top_block;
2441 : 1511 : BLOCK_SUBBLOCKS (top_block) = block;
2442 : :
2443 : 1511 : add_stmt (actor_bind);
2444 : 1511 : tree actor_body = push_stmt_list ();
2445 : :
2446 : : /* The entry point for the actor code from the ramp. */
2447 : 1511 : tree actor_begin_label
2448 : 1511 : = create_named_label_with_ctx (loc, "actor.begin", actor);
2449 : 1511 : tree actor_frame = build1_loc (loc, INDIRECT_REF, coro_frame_type, actor_fp);
2450 : :
2451 : : /* Declare the continuation handle. */
2452 : 1511 : add_decl_expr (continuation);
2453 : :
2454 : : /* Re-write local vars, similarly. */
2455 : 1511 : local_vars_transform xform_vars_data
2456 : 1511 : = {actor, actor_frame, coro_frame_type, loc, local_var_uses};
2457 : 1511 : cp_walk_tree (&fnbody, transform_local_var_uses, &xform_vars_data, NULL);
2458 : 1511 : tree rat = coro_build_frame_access_expr (actor_frame, coro_resume_index_id,
2459 : : false, tf_warning_or_error);
2460 : 1511 : tree ret_label
2461 : 1511 : = create_named_label_with_ctx (loc, "actor.suspend.ret", actor);
2462 : :
2463 : 1511 : tree continue_label
2464 : 1511 : = create_named_label_with_ctx (loc, "actor.continue.ret", actor);
2465 : :
2466 : : /* Build the dispatcher; for each await expression there is an odd entry
2467 : : corresponding to the destruction action and an even entry for the resume
2468 : : one:
2469 : : if (resume index is odd)
2470 : : {
2471 : : switch (resume index)
2472 : : case 1:
2473 : : goto cleanup.
2474 : : case ... odd suspension point number
2475 : : .CO_ACTOR (... odd suspension point number)
2476 : : break;
2477 : : default:
2478 : : break;
2479 : : }
2480 : : else
2481 : : {
2482 : : coro.restart.dispatch:
2483 : : case 0:
2484 : : goto start.
2485 : : case ... even suspension point number
2486 : : .CO_ACTOR (... even suspension point number)
2487 : : break;
2488 : : default:
2489 : : break;
2490 : : }
2491 : : we should not get here unless something is broken badly.
2492 : : __builtin_trap ();
2493 : : */
2494 : 1511 : tree lsb_if = begin_if_stmt ();
2495 : 1511 : tree chkb0 = build2 (BIT_AND_EXPR, short_unsigned_type_node, rat,
2496 : 1511 : build_int_cst (short_unsigned_type_node, 1));
2497 : 1511 : chkb0 = build2 (NE_EXPR, short_unsigned_type_node, chkb0,
2498 : 1511 : build_int_cst (short_unsigned_type_node, 0));
2499 : 1511 : finish_if_stmt_cond (chkb0, lsb_if);
2500 : :
2501 : 1511 : tree destroy_dispatcher = begin_switch_stmt ();
2502 : 1511 : finish_switch_cond (rat, destroy_dispatcher);
2503 : :
2504 : : /* The destroy point numbered #1 is special, in that it is reached from a
2505 : : coroutine that is suspended after re-throwing from unhandled_exception().
2506 : : This label just invokes the cleanup of promise, param copies and the
2507 : : frame itself. */
2508 : 1511 : tree del_promise_label
2509 : 1511 : = create_named_label_with_ctx (loc, "coro.delete.promise", actor);
2510 : 1511 : finish_case_label (loc, build_int_cst (short_unsigned_type_node, 1),
2511 : : NULL_TREE);
2512 : 1511 : add_stmt (build_stmt (loc, GOTO_EXPR, del_promise_label));
2513 : :
2514 : 1511 : short unsigned lab_num = 3;
2515 : 5565 : for (unsigned destr_pt = 0; destr_pt < body_count; destr_pt++)
2516 : : {
2517 : 4054 : tree l_num = build_int_cst (short_unsigned_type_node, lab_num);
2518 : 4054 : finish_case_label (loc, l_num, NULL_TREE);
2519 : 4054 : tree c = build_call_expr_internal_loc (loc, IFN_CO_ACTOR, void_type_node,
2520 : : 1, l_num);
2521 : 4054 : finish_expr_stmt (c);
2522 : 4054 : finish_break_stmt ();
2523 : 4054 : lab_num += 2;
2524 : : }
2525 : 1511 : finish_case_label (loc, NULL_TREE, NULL_TREE);
2526 : 1511 : finish_break_stmt ();
2527 : :
2528 : : /* Finish the destroy dispatcher. */
2529 : 1511 : finish_switch_stmt (destroy_dispatcher);
2530 : :
2531 : 1511 : finish_then_clause (lsb_if);
2532 : 1511 : begin_else_clause (lsb_if);
2533 : :
2534 : : /* For the case of a boolean await_resume () that returns 'true' we should
2535 : : restart the dispatch, since we cannot know if additional resumes were
2536 : : executed from within the await_suspend function. */
2537 : 1511 : tree restart_dispatch_label
2538 : 1511 : = create_named_label_with_ctx (loc, "coro.restart.dispatch", actor);
2539 : 1511 : add_stmt (build_stmt (loc, LABEL_EXPR, restart_dispatch_label));
2540 : :
2541 : 1511 : tree dispatcher = begin_switch_stmt ();
2542 : 1511 : finish_switch_cond (rat, dispatcher);
2543 : 1511 : finish_case_label (loc, build_int_cst (short_unsigned_type_node, 0),
2544 : : NULL_TREE);
2545 : 1511 : add_stmt (build_stmt (loc, GOTO_EXPR, actor_begin_label));
2546 : :
2547 : 1511 : lab_num = 2;
2548 : : /* The final resume should be made to hit the default (trap, UB) entry
2549 : : although it will be unreachable via the normal entry point, since that
2550 : : is set to NULL on reaching final suspend. */
2551 : 5565 : for (unsigned resu_pt = 0; resu_pt < body_count; resu_pt++)
2552 : : {
2553 : 4054 : tree l_num = build_int_cst (short_unsigned_type_node, lab_num);
2554 : 4054 : finish_case_label (loc, l_num, NULL_TREE);
2555 : 4054 : tree c = build_call_expr_internal_loc (loc, IFN_CO_ACTOR, void_type_node,
2556 : : 1, l_num);
2557 : 4054 : finish_expr_stmt (c);
2558 : 4054 : finish_break_stmt ();
2559 : 4054 : lab_num += 2;
2560 : : }
2561 : 1511 : finish_case_label (loc, NULL_TREE, NULL_TREE);
2562 : 1511 : finish_break_stmt ();
2563 : :
2564 : : /* Finish the resume dispatcher. */
2565 : 1511 : finish_switch_stmt (dispatcher);
2566 : :
2567 : 1511 : finish_else_clause (lsb_if);
2568 : 1511 : finish_if_stmt (lsb_if);
2569 : :
2570 : : /* If we reach here then we've hit UB. */
2571 : 1511 : tree t = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_TRAP), 0);
2572 : 1511 : finish_expr_stmt (t);
2573 : :
2574 : : /* Now we start building the rewritten function body. */
2575 : 1511 : add_stmt (build_stmt (loc, LABEL_EXPR, actor_begin_label));
2576 : :
2577 : : /* actor's coroutine 'self handle'. */
2578 : 1511 : tree ash = coro_build_frame_access_expr (actor_frame, coro_self_handle_id,
2579 : : false, tf_warning_or_error);
2580 : : /* So construct the self-handle from the frame address. */
2581 : 1511 : tree hfa_m = get_coroutine_from_address (orig);
2582 : : /* Should have been set earlier by coro_promise_type_found_p. */
2583 : 1511 : gcc_assert (hfa_m);
2584 : :
2585 : 1511 : tree r = build1 (CONVERT_EXPR, build_pointer_type (void_type_node), actor_fp);
2586 : 1511 : vec<tree, va_gc> *args = make_tree_vector_single (r);
2587 : 1511 : tree hfa = build_new_method_call (ash, hfa_m, &args, NULL_TREE, LOOKUP_NORMAL,
2588 : : NULL, tf_warning_or_error);
2589 : 1511 : r = cp_build_init_expr (ash, hfa);
2590 : 1511 : finish_expr_stmt (r);
2591 : 1511 : release_tree_vector (args);
2592 : :
2593 : : /* Now we know the real promise, and enough about the frame layout to
2594 : : decide where to put things. */
2595 : :
2596 : 1511 : await_xform_data xform = {actor, actor_frame, suspend_points};
2597 : :
2598 : : /* Transform the await expressions in the function body. Only do each
2599 : : await tree once! */
2600 : 1511 : hash_set<tree> pset;
2601 : 1511 : cp_walk_tree (&fnbody, transform_await_wrapper, &xform, &pset);
2602 : :
2603 : : /* Add in our function body with the co_returns rewritten to final form. */
2604 : 1511 : add_stmt (fnbody);
2605 : :
2606 : : /* Now do the tail of the function; first cleanups. */
2607 : 1511 : r = build_stmt (loc, LABEL_EXPR, del_promise_label);
2608 : 1511 : add_stmt (r);
2609 : :
2610 : : /* Destructors for the things we built explicitly.
2611 : : promise... */
2612 : 1511 : if (tree c = cxx_maybe_build_cleanup (promise_proxy, tf_warning_or_error))
2613 : 904 : finish_expr_stmt (c);
2614 : :
2615 : : /* Argument copies ... */
2616 : 1588 : while (!param_dtor_list->is_empty ())
2617 : : {
2618 : 77 : tree parm_id = param_dtor_list->pop ();
2619 : 77 : tree a = coro_build_frame_access_expr (actor_frame, parm_id, false,
2620 : : tf_warning_or_error);
2621 : 77 : if (tree dtor = cxx_maybe_build_cleanup (a, tf_warning_or_error))
2622 : 77 : finish_expr_stmt (dtor);
2623 : : }
2624 : :
2625 : : /* Here deallocate the frame (if we allocated it), which we will have at
2626 : : present. */
2627 : 1511 : tree fnf2_x
2628 : 1511 : = coro_build_frame_access_expr (actor_frame, coro_frame_needs_free_id,
2629 : : false, tf_warning_or_error);
2630 : 1511 : tree need_free_if = begin_if_stmt ();
2631 : 1511 : finish_if_stmt_cond (fnf2_x, need_free_if);
2632 : :
2633 : : /* Build the frame DTOR. */
2634 : 1511 : tree del_coro_fr
2635 : 1511 : = build_coroutine_frame_delete_expr (actor_fp, frame_size,
2636 : : promise_type, loc);
2637 : 1511 : finish_expr_stmt (del_coro_fr);
2638 : 1511 : finish_then_clause (need_free_if);
2639 : 1511 : finish_if_stmt (need_free_if);
2640 : :
2641 : : /* Done. */
2642 : 1511 : finish_return_stmt (NULL_TREE);
2643 : :
2644 : : /* This is the suspend return point. */
2645 : 1511 : add_stmt (build_stmt (loc, LABEL_EXPR, ret_label));
2646 : :
2647 : 1511 : finish_return_stmt (NULL_TREE);
2648 : :
2649 : : /* This is the 'continuation' return point. For such a case we have a coro
2650 : : handle (from the await_suspend() call) and we want handle.resume() to
2651 : : execute as a tailcall allowing arbitrary chaining of coroutines. */
2652 : 1511 : add_stmt (build_stmt (loc, LABEL_EXPR, continue_label));
2653 : :
2654 : : /* Should have been set earlier by the coro_initialized code. */
2655 : 1511 : gcc_assert (void_coro_handle_address);
2656 : :
2657 : : /* We want to force a tail-call even for O0/1, so this expands the resume
2658 : : call into its underlying implementation. */
2659 : 1511 : tree addr = build_new_method_call (continuation, void_coro_handle_address,
2660 : : NULL, NULL_TREE, LOOKUP_NORMAL, NULL,
2661 : : tf_warning_or_error);
2662 : 1511 : tree resume = build_call_expr_loc
2663 : 1511 : (loc, builtin_decl_explicit (BUILT_IN_CORO_RESUME), 1, addr);
2664 : :
2665 : : /* In order to support an arbitrary number of coroutine continuations,
2666 : : we must tail call them. However, some targets do not support indirect
2667 : : tail calls to arbitrary callees. See PR94359. */
2668 : 1511 : CALL_EXPR_TAILCALL (resume) = true;
2669 : 1511 : finish_expr_stmt (resume);
2670 : :
2671 : 1511 : r = build_stmt (loc, RETURN_EXPR, NULL);
2672 : 1511 : gcc_checking_assert (maybe_cleanup_point_expr_void (r) == r);
2673 : 1511 : add_stmt (r);
2674 : :
2675 : : /* We've now rewritten the tree and added the initial and final
2676 : : co_awaits. Now pass over the tree and expand the co_awaits. */
2677 : 1511 : tree i_a_r_c = NULL_TREE;
2678 : 1511 : if (flag_exceptions)
2679 : 1489 : i_a_r_c = coro_build_frame_access_expr (actor_frame, coro_frame_i_a_r_c_id,
2680 : : false, tf_warning_or_error);
2681 : :
2682 : 1511 : coro_aw_data data = {actor, actor_fp, resume_idx_var, i_a_r_c,
2683 : : ash, del_promise_label, ret_label,
2684 : 1511 : continue_label, restart_dispatch_label, continuation, 2};
2685 : 1511 : cp_walk_tree (&actor_body, await_statement_expander, &data, NULL);
2686 : :
2687 : 1511 : BIND_EXPR_BODY (actor_bind) = pop_stmt_list (actor_body);
2688 : 1511 : TREE_SIDE_EFFECTS (actor_bind) = true;
2689 : :
2690 : 1511 : cfun->coroutine_component = 1;
2691 : 1511 : finish_function_body (stmt);
2692 : 1511 : finish_function (inline_p);
2693 : 1511 : }
2694 : :
2695 : : /* The prototype 'destroy' function :
2696 : : frame->__Coro_resume_index |= 1;
2697 : : actor (frame); */
2698 : :
2699 : : static void
2700 : 1511 : build_destroy_fn (location_t loc, tree coro_frame_type, tree destroy,
2701 : : tree actor, bool inline_p)
2702 : : {
2703 : : /* One param, the coro frame pointer. */
2704 : 1511 : tree destr_fp = DECL_ARGUMENTS (destroy);
2705 : 1511 : gcc_checking_assert (POINTER_TYPE_P (TREE_TYPE (destr_fp))
2706 : : && same_type_p (coro_frame_type,
2707 : : TREE_TYPE (TREE_TYPE (destr_fp))));
2708 : :
2709 : 1511 : bool spf = start_preparsed_function (destroy, NULL_TREE, SF_PRE_PARSED);
2710 : 1511 : gcc_checking_assert (spf);
2711 : 1511 : tree dstr_stmt = begin_function_body ();
2712 : :
2713 : 1511 : tree destr_frame
2714 : 1511 : = cp_build_indirect_ref (loc, destr_fp, RO_UNARY_STAR,
2715 : : tf_warning_or_error);
2716 : :
2717 : 1511 : tree rat = coro_build_frame_access_expr (destr_frame, coro_resume_index_id,
2718 : : false, tf_warning_or_error);
2719 : :
2720 : : /* _resume_at |= 1 */
2721 : 1511 : tree dstr_idx
2722 : 1511 : = build2_loc (loc, BIT_IOR_EXPR, short_unsigned_type_node, rat,
2723 : 1511 : build_int_cst (short_unsigned_type_node, 1));
2724 : 1511 : tree r = cp_build_modify_expr (loc, rat, NOP_EXPR, dstr_idx,
2725 : : tf_warning_or_error);
2726 : 1511 : finish_expr_stmt (r);
2727 : :
2728 : : /* So .. call the actor .. */
2729 : 1511 : finish_expr_stmt (build_call_expr_loc (loc, actor, 1, destr_fp));
2730 : :
2731 : : /* done. */
2732 : 1511 : finish_return_stmt (NULL_TREE);
2733 : :
2734 : 1511 : gcc_checking_assert (cfun && current_function_decl);
2735 : 1511 : cfun->coroutine_component = 1;
2736 : 1511 : finish_function_body (dstr_stmt);
2737 : 1511 : finish_function (inline_p);
2738 : 1511 : }
2739 : :
2740 : : /* Helper that returns an identifier for an appended extension to the
2741 : : current un-mangled function name. */
2742 : :
2743 : : static tree
2744 : 1595 : get_fn_local_identifier (tree orig, const char *append)
2745 : : {
2746 : : /* Figure out the bits we need to generate names for the outlined things
2747 : : For consistency, this needs to behave the same way as
2748 : : ASM_FORMAT_PRIVATE_NAME does. */
2749 : 1595 : tree nm = DECL_NAME (orig);
2750 : 1595 : const char *sep, *pfx = "";
2751 : : #ifndef NO_DOT_IN_LABEL
2752 : 1595 : sep = ".";
2753 : : #else
2754 : : #ifndef NO_DOLLAR_IN_LABEL
2755 : : sep = "$";
2756 : : #else
2757 : : sep = "_";
2758 : : pfx = "__";
2759 : : #endif
2760 : : #endif
2761 : :
2762 : 1595 : char *an;
2763 : 1595 : if (DECL_ASSEMBLER_NAME (orig))
2764 : 1595 : an = ACONCAT ((IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (orig)), sep, append,
2765 : : (char *) 0));
2766 : 0 : else if (DECL_USE_TEMPLATE (orig) && DECL_TEMPLATE_INFO (orig)
2767 : 0 : && DECL_TI_ARGS (orig))
2768 : : {
2769 : 0 : tree tpl_args = DECL_TI_ARGS (orig);
2770 : 0 : an = ACONCAT ((pfx, IDENTIFIER_POINTER (nm), (char *) 0));
2771 : 0 : for (int i = 0; i < TREE_VEC_LENGTH (tpl_args); ++i)
2772 : : {
2773 : 0 : tree typ = DECL_NAME (TYPE_NAME (TREE_VEC_ELT (tpl_args, i)));
2774 : 0 : an = ACONCAT ((an, sep, IDENTIFIER_POINTER (typ), (char *) 0));
2775 : : }
2776 : 0 : an = ACONCAT ((an, sep, append, (char *) 0));
2777 : : }
2778 : : else
2779 : 0 : an = ACONCAT ((pfx, IDENTIFIER_POINTER (nm), sep, append, (char *) 0));
2780 : :
2781 : 1595 : return get_identifier (an);
2782 : : }
2783 : :
2784 : : /* Build an initial or final await initialized from the promise
2785 : : initial_suspend or final_suspend expression. */
2786 : :
2787 : : static tree
2788 : 3004 : build_init_or_final_await (location_t loc, bool is_final)
2789 : : {
2790 : 3004 : tree suspend_alt = is_final ? coro_final_suspend_identifier
2791 : : : coro_initial_suspend_identifier;
2792 : :
2793 : 3004 : tree setup_call
2794 : 3004 : = coro_build_promise_expression (current_function_decl, NULL, suspend_alt,
2795 : : loc, NULL, /*musthave=*/true);
2796 : :
2797 : : /* Check for noexcept on the final_suspend call. */
2798 : 2960 : if (flag_exceptions && is_final && setup_call != error_mark_node
2799 : 4478 : && coro_diagnose_throwing_final_aw_expr (setup_call))
2800 : 3 : return error_mark_node;
2801 : :
2802 : : /* So build the co_await for this */
2803 : : /* For initial/final suspends the call is "a" per [expr.await] 3.2. */
2804 : 4506 : return build_co_await (loc, setup_call, (is_final ? FINAL_SUSPEND_POINT
2805 : 3001 : : INITIAL_SUSPEND_POINT));
2806 : : }
2807 : :
2808 : : /* Callback to record the essential data for each await point found in the
2809 : : function. */
2810 : :
2811 : : static bool
2812 : 4096 : register_await_info (tree await_expr, tree aw_type, tree aw_nam,
2813 : : hash_map<tree, suspend_point_info> *suspend_points)
2814 : : {
2815 : 4096 : bool seen;
2816 : 4096 : suspend_point_info &s
2817 : 4096 : = suspend_points->get_or_insert (await_expr, &seen);
2818 : 4096 : if (seen)
2819 : : {
2820 : 0 : warning_at (EXPR_LOCATION (await_expr), 0, "duplicate info for %qE",
2821 : : await_expr);
2822 : 0 : return false;
2823 : : }
2824 : 4096 : s.awaitable_type = aw_type;
2825 : 4096 : s.await_field_id = aw_nam;
2826 : 4096 : return true;
2827 : : }
2828 : :
2829 : : /* If this is an await expression, then count it (both uniquely within the
2830 : : function and locally within a single statement). */
2831 : :
2832 : : static tree
2833 : 202272 : register_awaits (tree *stmt, int *, void *d)
2834 : : {
2835 : 202272 : tree aw_expr = *stmt;
2836 : :
2837 : : /* We should have already lowered co_yields to their co_await. */
2838 : 202272 : gcc_checking_assert (TREE_CODE (aw_expr) != CO_YIELD_EXPR);
2839 : :
2840 : 202272 : if (TREE_CODE (aw_expr) != CO_AWAIT_EXPR)
2841 : : return NULL_TREE;
2842 : :
2843 : : /* Count how many awaits the current expression contains. */
2844 : 4096 : susp_frame_data *data = (susp_frame_data *) d;
2845 : 4096 : data->saw_awaits++;
2846 : : /* Each await suspend context is unique, this is a function-wide value. */
2847 : 4096 : data->await_number++;
2848 : :
2849 : : /* Awaitables should either be user-locals or promoted to coroutine frame
2850 : : entries at this point, and their initializers should have been broken
2851 : : out. */
2852 : 4096 : tree aw = TREE_OPERAND (aw_expr, 1);
2853 : 4096 : gcc_checking_assert (!TREE_OPERAND (aw_expr, 2));
2854 : :
2855 : 4096 : tree aw_field_type = TREE_TYPE (aw);
2856 : 4096 : tree aw_field_nam = NULL_TREE;
2857 : 4096 : register_await_info (aw_expr, aw_field_type, aw_field_nam, data->suspend_points);
2858 : :
2859 : : /* Rewrite target expressions on the await_suspend () to remove extraneous
2860 : : cleanups for the awaitables, which are now promoted to frame vars and
2861 : : managed via that. */
2862 : 4096 : tree v = TREE_OPERAND (aw_expr, 3);
2863 : 4096 : tree o = TREE_VEC_ELT (v, 1);
2864 : 4096 : if (TREE_CODE (o) == TARGET_EXPR)
2865 : 114 : TREE_VEC_ELT (v, 1) = get_target_expr (TARGET_EXPR_INITIAL (o));
2866 : : return NULL_TREE;
2867 : : }
2868 : :
2869 : : /* There are cases where any await expression is relevant. */
2870 : : static tree
2871 : 437927 : find_any_await (tree *stmt, int *dosub, void *d)
2872 : : {
2873 : 437927 : if (TREE_CODE (*stmt) == CO_AWAIT_EXPR)
2874 : : {
2875 : 4196 : *dosub = 0; /* We don't need to consider this any further. */
2876 : 4196 : if (d)
2877 : 4187 : *(tree **)d = stmt;
2878 : 4196 : return *stmt;
2879 : : }
2880 : : return NULL_TREE;
2881 : : }
2882 : :
2883 : : static bool
2884 : 68893 : tmp_target_expr_p (tree t)
2885 : : {
2886 : 68893 : if (TREE_CODE (t) != TARGET_EXPR)
2887 : : return false;
2888 : 5031 : tree v = TARGET_EXPR_SLOT (t);
2889 : 5031 : if (!DECL_ARTIFICIAL (v))
2890 : : return false;
2891 : 5031 : if (DECL_NAME (v))
2892 : 182 : return false;
2893 : : return true;
2894 : : }
2895 : :
2896 : : /* Structure to record sub-expressions that need to be handled by the
2897 : : statement flattener. */
2898 : :
2899 : : struct coro_interesting_subtree
2900 : : {
2901 : : tree* entry;
2902 : : hash_set<tree> *temps_used;
2903 : : };
2904 : :
2905 : : /* tree-walk callback that returns the first encountered sub-expression of
2906 : : a kind that needs to be handled specifically by the statement flattener. */
2907 : :
2908 : : static tree
2909 : 77046 : find_interesting_subtree (tree *expr_p, int *dosub, void *d)
2910 : : {
2911 : 77046 : tree expr = *expr_p;
2912 : 77046 : coro_interesting_subtree *p = (coro_interesting_subtree *)d;
2913 : 77046 : if (TREE_CODE (expr) == CO_AWAIT_EXPR)
2914 : : {
2915 : 8153 : *dosub = 0; /* We don't need to consider this any further. */
2916 : 8153 : if (TREE_OPERAND (expr, 2))
2917 : : {
2918 : 4043 : p->entry = expr_p;
2919 : 4043 : return expr;
2920 : : }
2921 : : }
2922 : 68893 : else if (tmp_target_expr_p (expr)
2923 : 4849 : && !TARGET_EXPR_ELIDING_P (expr)
2924 : 69237 : && !p->temps_used->contains (expr))
2925 : : {
2926 : 327 : p->entry = expr_p;
2927 : 327 : return expr;
2928 : : }
2929 : :
2930 : : return NULL_TREE;
2931 : : }
2932 : :
2933 : : /* Node for a doubly-linked list of promoted variables and their
2934 : : initializers. When the initializer is a conditional expression
2935 : : the 'then' and 'else' clauses are represented by a linked list
2936 : : attached to then_cl and else_cl respectively. */
2937 : :
2938 : : struct var_nest_node
2939 : : {
2940 : : var_nest_node () = default;
2941 : 8461 : var_nest_node (tree v, tree i, var_nest_node *p, var_nest_node *n)
2942 : 8461 : : var(v), init(i), prev(p), next(n), then_cl (NULL), else_cl (NULL)
2943 : : {
2944 : 8461 : if (p)
2945 : 26 : p->next = this;
2946 : 26 : if (n)
2947 : 4403 : n->prev = this;
2948 : : }
2949 : : tree var;
2950 : : tree init;
2951 : : var_nest_node *prev;
2952 : : var_nest_node *next;
2953 : : var_nest_node *then_cl;
2954 : : var_nest_node *else_cl;
2955 : : };
2956 : :
2957 : : /* This is called for single statements from the co-await statement walker.
2958 : : It checks to see if the statement contains any initializers for awaitables
2959 : : and if any of these capture items by reference. */
2960 : :
2961 : : static void
2962 : 12831 : flatten_await_stmt (var_nest_node *n, hash_set<tree> *promoted,
2963 : : hash_set<tree> *temps_used, tree *replace_in)
2964 : : {
2965 : 12946 : bool init_expr = false;
2966 : 12946 : switch (TREE_CODE (n->init))
2967 : : {
2968 : : default: break;
2969 : : /* Compound expressions must be flattened specifically. */
2970 : 15 : case COMPOUND_EXPR:
2971 : 15 : {
2972 : 15 : tree first = TREE_OPERAND (n->init, 0);
2973 : 15 : n->init = TREE_OPERAND (n->init, 1);
2974 : 15 : var_nest_node *ins
2975 : 15 : = new var_nest_node(NULL_TREE, first, n->prev, n);
2976 : : /* The compiler (but not the user) can generate temporaries with
2977 : : uses in the second arm of a compound expr. */
2978 : 15 : flatten_await_stmt (ins, promoted, temps_used, &n->init);
2979 : 15 : flatten_await_stmt (n, promoted, temps_used, NULL);
2980 : : /* The two arms have been processed separately. */
2981 : 12846 : return;
2982 : : }
2983 : 5164 : break;
2984 : : /* Handle conditional expressions. */
2985 : 5164 : case INIT_EXPR:
2986 : 5164 : init_expr = true;
2987 : : /* FALLTHROUGH */
2988 : 5533 : case MODIFY_EXPR:
2989 : 5533 : {
2990 : 5533 : tree old_expr = TREE_OPERAND (n->init, 1);
2991 : 5533 : if (TREE_CODE (old_expr) == COMPOUND_EXPR)
2992 : : {
2993 : 100 : tree first = TREE_OPERAND (old_expr, 0);
2994 : 100 : TREE_OPERAND (n->init, 1) = TREE_OPERAND (old_expr, 1);
2995 : 100 : var_nest_node *ins
2996 : 100 : = new var_nest_node(NULL_TREE, first, n->prev, n);
2997 : 100 : flatten_await_stmt (ins, promoted, temps_used,
2998 : : &TREE_OPERAND (n->init, 1));
2999 : 100 : flatten_await_stmt (n, promoted, temps_used, NULL);
3000 : 100 : return;
3001 : : }
3002 : 5433 : if (TREE_CODE (old_expr) != COND_EXPR)
3003 : : break;
3004 : : /* Reconstruct x = t ? y : z;
3005 : : as (void) t ? x = y : x = z; */
3006 : 14 : tree var = TREE_OPERAND (n->init, 0);
3007 : 14 : tree var_type = TREE_TYPE (var);
3008 : 14 : tree cond = COND_EXPR_COND (old_expr);
3009 : : /* We are allowed a void type throw in one or both of the cond
3010 : : expr arms. */
3011 : 14 : tree then_cl = COND_EXPR_THEN (old_expr);
3012 : 14 : if (!VOID_TYPE_P (TREE_TYPE (then_cl)))
3013 : : {
3014 : 14 : gcc_checking_assert (TREE_CODE (then_cl) != STATEMENT_LIST);
3015 : 14 : if (init_expr)
3016 : 14 : then_cl = cp_build_init_expr (var, then_cl);
3017 : : else
3018 : 0 : then_cl = build2 (MODIFY_EXPR, var_type, var, then_cl);
3019 : : }
3020 : 14 : tree else_cl = COND_EXPR_ELSE (old_expr);
3021 : 14 : if (!VOID_TYPE_P (TREE_TYPE (else_cl)))
3022 : : {
3023 : 14 : gcc_checking_assert (TREE_CODE (else_cl) != STATEMENT_LIST);
3024 : 14 : if (init_expr)
3025 : 14 : else_cl = cp_build_init_expr (var, else_cl);
3026 : : else
3027 : 0 : else_cl = build2 (MODIFY_EXPR, var_type, var, else_cl);
3028 : : }
3029 : 14 : n->init = build3 (COND_EXPR, var_type, cond, then_cl, else_cl);
3030 : : }
3031 : : /* FALLTHROUGH */
3032 : 17 : case COND_EXPR:
3033 : 17 : {
3034 : 17 : tree *found;
3035 : 17 : tree cond = COND_EXPR_COND (n->init);
3036 : : /* If the condition contains an await expression, then we need to
3037 : : set that first and use a separate var. */
3038 : 17 : if (cp_walk_tree (&cond, find_any_await, &found, NULL))
3039 : : {
3040 : 17 : tree cond_type = TREE_TYPE (cond);
3041 : 17 : tree cond_var = build_lang_decl (VAR_DECL, NULL_TREE, cond_type);
3042 : 17 : DECL_ARTIFICIAL (cond_var) = true;
3043 : 17 : layout_decl (cond_var, 0);
3044 : 17 : gcc_checking_assert (!TYPE_NEEDS_CONSTRUCTING (cond_type));
3045 : 17 : cond = cp_build_init_expr (cond_var, cond);
3046 : 17 : var_nest_node *ins
3047 : 17 : = new var_nest_node (cond_var, cond, n->prev, n);
3048 : 17 : COND_EXPR_COND (n->init) = cond_var;
3049 : 17 : flatten_await_stmt (ins, promoted, temps_used, NULL);
3050 : : }
3051 : :
3052 : 17 : n->then_cl
3053 : 17 : = new var_nest_node (n->var, COND_EXPR_THEN (n->init), NULL, NULL);
3054 : 17 : n->else_cl
3055 : 17 : = new var_nest_node (n->var, COND_EXPR_ELSE (n->init), NULL, NULL);
3056 : 17 : flatten_await_stmt (n->then_cl, promoted, temps_used, NULL);
3057 : : /* Point to the start of the flattened code. */
3058 : 51 : while (n->then_cl->prev)
3059 : 17 : n->then_cl = n->then_cl->prev;
3060 : 17 : flatten_await_stmt (n->else_cl, promoted, temps_used, NULL);
3061 : 34 : while (n->else_cl->prev)
3062 : 0 : n->else_cl = n->else_cl->prev;
3063 : 17 : return;
3064 : : }
3065 : 12814 : break;
3066 : : }
3067 : 12814 : coro_interesting_subtree v = { NULL, temps_used };
3068 : 12814 : tree t = cp_walk_tree (&n->init, find_interesting_subtree, (void *)&v, NULL);
3069 : 12814 : if (!t)
3070 : : return;
3071 : 4370 : switch (TREE_CODE (t))
3072 : : {
3073 : 0 : default: break;
3074 : 4043 : case CO_AWAIT_EXPR:
3075 : 4043 : {
3076 : : /* Await expressions with initializers have a compiler-temporary
3077 : : as the awaitable. 'promote' this. */
3078 : 4043 : tree var = TREE_OPERAND (t, 1);
3079 : 4043 : bool already_present = promoted->add (var);
3080 : 4043 : gcc_checking_assert (!already_present);
3081 : 4043 : tree init = TREE_OPERAND (t, 2);
3082 : 4043 : switch (TREE_CODE (init))
3083 : : {
3084 : : default: break;
3085 : 4043 : case INIT_EXPR:
3086 : 4043 : case MODIFY_EXPR:
3087 : 4043 : {
3088 : 4043 : tree inner = TREE_OPERAND (init, 1);
3089 : : /* We can have non-lvalue-expressions here, but when we see
3090 : : a target expression, mark it as already used. */
3091 : 4043 : if (TREE_CODE (inner) == TARGET_EXPR)
3092 : : {
3093 : 3996 : temps_used->add (inner);
3094 : 3996 : gcc_checking_assert
3095 : : (TREE_CODE (TARGET_EXPR_INITIAL (inner)) != COND_EXPR);
3096 : : }
3097 : : }
3098 : 4043 : break;
3099 : 0 : case CALL_EXPR:
3100 : : /* If this is a call and not a CTOR, then we didn't expect it. */
3101 : 0 : gcc_checking_assert
3102 : : (DECL_CONSTRUCTOR_P (TREE_OPERAND (CALL_EXPR_FN (init), 0)));
3103 : : break;
3104 : : }
3105 : 4043 : var_nest_node *ins = new var_nest_node (var, init, n->prev, n);
3106 : 4043 : TREE_OPERAND (t, 2) = NULL_TREE;
3107 : 4043 : flatten_await_stmt (ins, promoted, temps_used, NULL);
3108 : 4043 : flatten_await_stmt (n, promoted, temps_used, NULL);
3109 : 4043 : return;
3110 : : }
3111 : 327 : break;
3112 : 327 : case TARGET_EXPR:
3113 : 327 : {
3114 : : /* We have a temporary; promote it, but allow for the idiom in code
3115 : : generated by the compiler like
3116 : : a = (target_expr produces temp, op uses temp). */
3117 : 327 : tree init = t;
3118 : 327 : temps_used->add (init);
3119 : 327 : tree var_type = TREE_TYPE (init);
3120 : 327 : char *buf = xasprintf ("T%03u", (unsigned) temps_used->elements ());
3121 : 327 : tree var = build_lang_decl (VAR_DECL, get_identifier (buf), var_type);
3122 : 327 : DECL_ARTIFICIAL (var) = true;
3123 : 327 : free (buf);
3124 : 327 : bool already_present = promoted->add (var);
3125 : 327 : gcc_checking_assert (!already_present);
3126 : 327 : tree inner = TARGET_EXPR_INITIAL (init);
3127 : 327 : gcc_checking_assert
3128 : : (TREE_CODE (inner) != COND_EXPR
3129 : : || !cp_walk_tree (&inner, find_any_await, nullptr, nullptr));
3130 : 327 : init = cp_build_modify_expr (input_location, var, INIT_EXPR, init,
3131 : : tf_warning_or_error);
3132 : : /* Simplify for the case that we have an init containing the temp
3133 : : alone. */
3134 : 327 : if (t == n->init && n->var == NULL_TREE)
3135 : : {
3136 : 99 : n->var = var;
3137 : 99 : proxy_replace pr = {TARGET_EXPR_SLOT (t), var};
3138 : 99 : cp_walk_tree (&init, replace_proxy, &pr, NULL);
3139 : 99 : n->init = init;
3140 : 99 : if (replace_in)
3141 : 91 : cp_walk_tree (replace_in, replace_proxy, &pr, NULL);
3142 : 99 : flatten_await_stmt (n, promoted, temps_used, NULL);
3143 : 99 : }
3144 : : else
3145 : : {
3146 : 228 : var_nest_node *ins
3147 : 228 : = new var_nest_node (var, init, n->prev, n);
3148 : : /* We have to replace the target expr... */
3149 : 228 : *v.entry = var;
3150 : : /* ... and any uses of its var. */
3151 : 228 : proxy_replace pr = {TARGET_EXPR_SLOT (t), var};
3152 : 228 : cp_walk_tree (&n->init, replace_proxy, &pr, NULL);
3153 : : /* Compiler-generated temporaries can also have uses in
3154 : : following arms of compound expressions, which will be listed
3155 : : in 'replace_in' if present. */
3156 : 228 : if (replace_in)
3157 : 3 : cp_walk_tree (replace_in, replace_proxy, &pr, NULL);
3158 : 228 : flatten_await_stmt (ins, promoted, temps_used, NULL);
3159 : 228 : flatten_await_stmt (n, promoted, temps_used, NULL);
3160 : : }
3161 : 327 : return;
3162 : : }
3163 : 0 : break;
3164 : : }
3165 : : }
3166 : :
3167 : : /* Helper for 'process_conditional' that handles recursion into nested
3168 : : conditionals. */
3169 : :
3170 : : static void
3171 : 34 : handle_nested_conditionals (var_nest_node *n, vec<tree>& list,
3172 : : hash_map<tree, tree>& map)
3173 : : {
3174 : 51 : do
3175 : : {
3176 : 51 : if (n->var && DECL_NAME (n->var))
3177 : : {
3178 : 17 : list.safe_push (n->var);
3179 : 17 : if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (n->var)))
3180 : : {
3181 : 0 : bool existed;
3182 : 0 : tree& flag = map.get_or_insert (n->var, &existed);
3183 : 0 : if (!existed)
3184 : : {
3185 : : /* We didn't see this var before and it needs a DTOR, so
3186 : : build a guard variable for it. */
3187 : 0 : char *nam
3188 : 0 : = xasprintf ("%s_guard",
3189 : 0 : IDENTIFIER_POINTER (DECL_NAME (n->var)));
3190 : 0 : flag = build_lang_decl (VAR_DECL, get_identifier (nam),
3191 : : boolean_type_node);
3192 : 0 : free (nam);
3193 : 0 : DECL_ARTIFICIAL (flag) = true;
3194 : : }
3195 : :
3196 : : /* The initializer for this variable is replaced by a compound
3197 : : expression that performs the init and then records that the
3198 : : variable is live (and the DTOR should be run at the scope
3199 : : exit. */
3200 : 0 : tree set_flag = cp_build_init_expr (flag, boolean_true_node);
3201 : 0 : n->init
3202 : 0 : = build2 (COMPOUND_EXPR, boolean_type_node, n->init, set_flag);
3203 : : }
3204 : : }
3205 : 51 : if (TREE_CODE (n->init) == COND_EXPR)
3206 : : {
3207 : 0 : tree new_then = push_stmt_list ();
3208 : 0 : handle_nested_conditionals (n->then_cl, list, map);
3209 : 0 : new_then = pop_stmt_list (new_then);
3210 : 0 : tree new_else = push_stmt_list ();
3211 : 0 : handle_nested_conditionals (n->else_cl, list, map);
3212 : 0 : new_else = pop_stmt_list (new_else);
3213 : 0 : tree new_if
3214 : 0 : = build4 (IF_STMT, void_type_node, COND_EXPR_COND (n->init),
3215 : : new_then, new_else, NULL_TREE);
3216 : 0 : add_stmt (new_if);
3217 : : }
3218 : : else
3219 : 51 : finish_expr_stmt (n->init);
3220 : 51 : n = n->next;
3221 : 51 : } while (n);
3222 : 34 : }
3223 : :
3224 : : /* helper for 'maybe_promote_temps'.
3225 : :
3226 : : When we have a conditional expression which might embed await expressions
3227 : : and/or promoted variables, we need to handle it appropriately.
3228 : :
3229 : : The linked lists for the 'then' and 'else' clauses in a conditional node
3230 : : identify the promoted variables (but these cannot be wrapped in a regular
3231 : : cleanup).
3232 : :
3233 : : So recurse through the lists and build up a composite list of captured vars.
3234 : : Declare these and any guard variables needed to decide if a DTOR should be
3235 : : run. Then embed the conditional into a try-finally expression that handles
3236 : : running each DTOR conditionally on its guard variable. */
3237 : :
3238 : : static void
3239 : 17 : process_conditional (var_nest_node *n, tree& vlist)
3240 : : {
3241 : 17 : tree init = n->init;
3242 : 17 : hash_map<tree, tree> var_flags;
3243 : 17 : auto_vec<tree> var_list;
3244 : 17 : tree new_then = push_stmt_list ();
3245 : 17 : handle_nested_conditionals (n->then_cl, var_list, var_flags);
3246 : 17 : new_then = pop_stmt_list (new_then);
3247 : 17 : tree new_else = push_stmt_list ();
3248 : 17 : handle_nested_conditionals (n->else_cl, var_list, var_flags);
3249 : 17 : new_else = pop_stmt_list (new_else);
3250 : : /* Declare the vars. There are two loops so that the boolean flags are
3251 : : grouped in the frame. */
3252 : 68 : for (unsigned i = 0; i < var_list.length(); i++)
3253 : : {
3254 : 17 : tree var = var_list[i];
3255 : 17 : DECL_CHAIN (var) = vlist;
3256 : 17 : vlist = var;
3257 : 17 : add_decl_expr (var);
3258 : : }
3259 : : /* Define the guard flags for variables that need a DTOR. */
3260 : 34 : for (unsigned i = 0; i < var_list.length(); i++)
3261 : : {
3262 : 17 : tree *flag = var_flags.get (var_list[i]);
3263 : 17 : if (flag)
3264 : : {
3265 : 0 : DECL_INITIAL (*flag) = boolean_false_node;
3266 : 0 : DECL_CHAIN (*flag) = vlist;
3267 : 0 : vlist = *flag;
3268 : 0 : add_decl_expr (*flag);
3269 : : }
3270 : : }
3271 : 17 : tree new_if
3272 : 17 : = build4 (IF_STMT, void_type_node, COND_EXPR_COND (init),
3273 : : new_then, new_else, NULL_TREE);
3274 : : /* Build a set of conditional DTORs. */
3275 : 17 : tree final_actions = push_stmt_list ();
3276 : 51 : while (!var_list.is_empty())
3277 : : {
3278 : 17 : tree var = var_list.pop ();
3279 : 17 : tree *flag = var_flags.get (var);
3280 : 34 : if (!flag)
3281 : 17 : continue;
3282 : 0 : if (tree cleanup = cxx_maybe_build_cleanup (var, tf_warning_or_error))
3283 : : {
3284 : 0 : tree cond_cleanup = begin_if_stmt ();
3285 : 0 : finish_if_stmt_cond (*flag, cond_cleanup);
3286 : 0 : finish_expr_stmt (cleanup);
3287 : 0 : finish_then_clause (cond_cleanup);
3288 : 0 : finish_if_stmt (cond_cleanup);
3289 : : }
3290 : : }
3291 : 17 : final_actions = pop_stmt_list (final_actions);
3292 : 17 : tree try_finally
3293 : 17 : = build2 (TRY_FINALLY_EXPR, void_type_node, new_if, final_actions);
3294 : 17 : add_stmt (try_finally);
3295 : 17 : }
3296 : :
3297 : : /* Given *STMT, that contains at least one await expression.
3298 : :
3299 : : The full expression represented in the original source code will contain
3300 : : suspension points, but it is still required that the lifetime of temporary
3301 : : values extends to the end of the expression.
3302 : :
3303 : : We already have a mechanism to 'promote' user-authored local variables
3304 : : to a coroutine frame counterpart (which allows explicit management of the
3305 : : lifetime across suspensions). The transform here re-writes STMT into
3306 : : a bind expression, promotes temporary values into local variables in that
3307 : : and flattens the statement into a series of cleanups.
3308 : :
3309 : : Conditional expressions are re-written to regular 'if' statements.
3310 : : The cleanups for variables initialized inside a conditional (including
3311 : : nested cases) are wrapped in a try-finally clause, with guard variables
3312 : : to determine which DTORs need to be run. */
3313 : :
3314 : : static tree
3315 : 4024 : maybe_promote_temps (tree *stmt, void *d)
3316 : : {
3317 : 4024 : susp_frame_data *awpts = (susp_frame_data *) d;
3318 : :
3319 : 4024 : location_t sloc = EXPR_LOCATION (*stmt);
3320 : 4024 : tree expr = *stmt;
3321 : : /* Strip off uninteresting wrappers. */
3322 : 4024 : if (TREE_CODE (expr) == CLEANUP_POINT_EXPR)
3323 : 4021 : expr = TREE_OPERAND (expr, 0);
3324 : 4024 : if (TREE_CODE (expr) == EXPR_STMT)
3325 : 4024 : expr = EXPR_STMT_EXPR (expr);
3326 : 4024 : if (TREE_CODE (expr) == CONVERT_EXPR
3327 : 4024 : && VOID_TYPE_P (TREE_TYPE (expr)))
3328 : 510 : expr = TREE_OPERAND (expr, 0);
3329 : 4024 : STRIP_NOPS (expr);
3330 : :
3331 : : /* We walk the statement trees, flattening it into an ordered list of
3332 : : variables with initializers and fragments corresponding to compound
3333 : : expressions, truth or/and if and ternary conditionals. Conditional
3334 : : expressions carry a nested list of fragments for the then and else
3335 : : clauses. We anchor to the 'bottom' of the fragment list; we will write
3336 : : a cleanup nest with one shell for each variable initialized. */
3337 : 4024 : var_nest_node *root = new var_nest_node (NULL_TREE, expr, NULL, NULL);
3338 : : /* Check to see we didn't promote one twice. */
3339 : 4024 : hash_set<tree> promoted_vars;
3340 : 4024 : hash_set<tree> used_temps;
3341 : 4024 : flatten_await_stmt (root, &promoted_vars, &used_temps, NULL);
3342 : :
3343 : 4024 : gcc_checking_assert (root->next == NULL);
3344 : 4024 : tree vlist = NULL_TREE;
3345 : 4024 : var_nest_node *t = root;
3346 : : /* We build the bind scope expression from the bottom-up.
3347 : : EXPR_LIST holds the inner expression nest at the current cleanup
3348 : : level (becoming the final expression list when we've exhausted the
3349 : : number of sub-expression fragments). */
3350 : 4024 : tree expr_list = NULL_TREE;
3351 : 8410 : do
3352 : : {
3353 : 8410 : tree new_list = push_stmt_list ();
3354 : : /* When we have a promoted variable, then add that to the bind scope
3355 : : and initialize it. When there's no promoted variable, we just need
3356 : : to run the initializer.
3357 : : If the initializer is a conditional expression, we need to collect
3358 : : and declare any promoted variables nested within it. DTORs for such
3359 : : variables must be run conditionally too.
3360 : :
3361 : : Since here we're synthetically processing code here, we've already
3362 : : emitted any Wunused-result warnings. Below, however, we call
3363 : : finish_expr_stmt, which will convert its operand to void, and could
3364 : : result in such a diagnostic being emitted. To avoid that, convert to
3365 : : void ahead of time. */
3366 : 8410 : if (t->var)
3367 : : {
3368 : 4370 : tree var = t->var;
3369 : 4370 : DECL_CHAIN (var) = vlist;
3370 : 4370 : vlist = var;
3371 : 4370 : add_decl_expr (var);
3372 : 4370 : if (TREE_CODE (t->init) == COND_EXPR)
3373 : 0 : process_conditional (t, vlist);
3374 : : else
3375 : 4370 : finish_expr_stmt (convert_to_void (t->init, ICV_STATEMENT, tf_none));
3376 : 4370 : if (tree cleanup = cxx_maybe_build_cleanup (var, tf_warning_or_error))
3377 : : {
3378 : 2010 : tree cl = build_stmt (sloc, CLEANUP_STMT, expr_list, cleanup, var);
3379 : 2010 : add_stmt (cl); /* push this onto the level above. */
3380 : : }
3381 : 2360 : else if (expr_list)
3382 : : {
3383 : 2356 : if (TREE_CODE (expr_list) != STATEMENT_LIST)
3384 : 2106 : add_stmt (expr_list);
3385 : 250 : else if (!tsi_end_p (tsi_start (expr_list)))
3386 : 250 : add_stmt (expr_list);
3387 : : }
3388 : : }
3389 : : else
3390 : : {
3391 : 4040 : if (TREE_CODE (t->init) == COND_EXPR)
3392 : 17 : process_conditional (t, vlist);
3393 : : else
3394 : 4023 : finish_expr_stmt (convert_to_void (t->init, ICV_STATEMENT, tf_none));
3395 : 4040 : if (expr_list)
3396 : : {
3397 : 24 : if (TREE_CODE (expr_list) != STATEMENT_LIST)
3398 : 12 : add_stmt (expr_list);
3399 : 12 : else if (!tsi_end_p (tsi_start (expr_list)))
3400 : 12 : add_stmt (expr_list);
3401 : : }
3402 : : }
3403 : 8410 : expr_list = pop_stmt_list (new_list);
3404 : 8410 : var_nest_node *old = t;
3405 : 8410 : t = t->prev;
3406 : 8410 : delete old;
3407 : 8410 : } while (t);
3408 : :
3409 : : /* Now produce the bind expression containing the 'promoted' temporaries
3410 : : as its variable list, and the cleanup nest as the statement. */
3411 : 4024 : tree await_bind = build3_loc (sloc, BIND_EXPR, void_type_node,
3412 : : NULL, NULL, NULL);
3413 : 4024 : BIND_EXPR_BODY (await_bind) = expr_list;
3414 : 4024 : BIND_EXPR_VARS (await_bind) = nreverse (vlist);
3415 : 4024 : tree b_block = make_node (BLOCK);
3416 : 4024 : if (!awpts->block_stack->is_empty ())
3417 : : {
3418 : 4024 : tree s_block = awpts->block_stack->last ();
3419 : 4024 : if (s_block)
3420 : : {
3421 : 4024 : BLOCK_SUPERCONTEXT (b_block) = s_block;
3422 : 4024 : BLOCK_CHAIN (b_block) = BLOCK_SUBBLOCKS (s_block);
3423 : 4024 : BLOCK_SUBBLOCKS (s_block) = b_block;
3424 : : }
3425 : : }
3426 : 4024 : BLOCK_VARS (b_block) = BIND_EXPR_VARS (await_bind) ;
3427 : 4024 : BIND_EXPR_BLOCK (await_bind) = b_block;
3428 : 4024 : TREE_SIDE_EFFECTS (await_bind) = TREE_SIDE_EFFECTS (BIND_EXPR_BODY (await_bind));
3429 : 4024 : *stmt = await_bind;
3430 : 4024 : hash_set<tree> visited;
3431 : 4024 : return cp_walk_tree (stmt, register_awaits, d, &visited);
3432 : 4024 : }
3433 : :
3434 : : /* Relatively lightweight callback to do initial assessment:
3435 : : 0) Rewrite some await expressions.
3436 : : 1) If the statement/expression contains any await expressions.
3437 : : 2) If the statement/expression potentially requires a re-write to handle
3438 : : TRUTH_{AND,OR}IF_EXPRs since, in most cases, they will need expansion
3439 : : so that the await expressions are not processed in the case of the
3440 : : short-circuit arm.
3441 : :
3442 : : CO_YIELD expressions are re-written to their underlying co_await. */
3443 : :
3444 : : static tree
3445 : 153230 : analyze_expression_awaits (tree *stmt, int *do_subtree, void *d)
3446 : : {
3447 : 153230 : susp_frame_data *awpts = (susp_frame_data *) d;
3448 : :
3449 : 153230 : switch (TREE_CODE (*stmt))
3450 : : {
3451 : : default: return NULL_TREE;
3452 : 18445 : case CALL_EXPR:
3453 : 18445 : {
3454 : 18445 : tree fn = cp_get_callee_fndecl_nofold (*stmt);
3455 : : /* Special-cases where we want to re-write await expressions to some
3456 : : other value before they are otherwise processed. */
3457 : 18445 : if (fn && DECL_IS_BUILTIN_CONSTANT_P (fn))
3458 : : {
3459 : 9 : gcc_checking_assert (call_expr_nargs (*stmt) == 1);
3460 : 9 : tree expr = CALL_EXPR_ARG (*stmt, 0);
3461 : 9 : if (cp_walk_tree (&expr, find_any_await, nullptr, NULL))
3462 : : {
3463 : 9 : if (TREE_CONSTANT (maybe_constant_value (expr)))
3464 : 3 : *stmt = integer_one_node;
3465 : : else
3466 : 6 : *stmt = integer_zero_node;
3467 : : }
3468 : 9 : *do_subtree = 0;
3469 : : }
3470 : : }
3471 : : break;
3472 : 376 : case CO_YIELD_EXPR:
3473 : : /* co_yield is syntactic sugar, re-write it to co_await. */
3474 : 376 : *stmt = TREE_OPERAND (*stmt, 1);
3475 : : /* FALLTHROUGH */
3476 : 4096 : case CO_AWAIT_EXPR:
3477 : 4096 : awpts->saw_awaits++;
3478 : : /* A non-null initializer for the awaiter means we need to expand. */
3479 : 4096 : if (TREE_OPERAND (*stmt, 2))
3480 : 4043 : awpts->has_awaiter_init = true;
3481 : : break;
3482 : 33 : case TRUTH_ANDIF_EXPR:
3483 : 33 : case TRUTH_ORIF_EXPR:
3484 : 33 : {
3485 : : /* We don't need special action for awaits in the always-executed
3486 : : arm of a TRUTH_IF. */
3487 : 33 : if (tree res = cp_walk_tree (&TREE_OPERAND (*stmt, 0),
3488 : : analyze_expression_awaits, d, NULL))
3489 : : return res;
3490 : : /* However, if there are await expressions on the conditionally
3491 : : executed branch, we must expand the TRUTH_IF to ensure that the
3492 : : expanded await expression control-flow is fully contained in the
3493 : : conditionally executed code. */
3494 : 33 : unsigned aw_count = awpts->saw_awaits;
3495 : 33 : if (tree res = cp_walk_tree (&TREE_OPERAND (*stmt, 1),
3496 : : analyze_expression_awaits, d, NULL))
3497 : : return res;
3498 : 33 : if (awpts->saw_awaits > aw_count)
3499 : : {
3500 : 17 : awpts->truth_aoif_to_expand->add (*stmt);
3501 : 17 : awpts->needs_truth_if_exp = true;
3502 : : }
3503 : : /* We've done the sub-trees here. */
3504 : 33 : *do_subtree = 0;
3505 : : }
3506 : 33 : break;
3507 : : }
3508 : :
3509 : : return NULL_TREE; /* Recurse until done. */
3510 : : }
3511 : :
3512 : : /* Given *EXPR
3513 : : If EXPR contains a TRUTH_{AND,OR}IF_EXPR, TAOIE with an await expr on
3514 : : the conditionally executed branch, change this in a ternary operator.
3515 : :
3516 : : bool not_expr = TAOIE == TRUTH_ORIF_EXPR ? NOT : NOP;
3517 : : not_expr (always-exec expr) ? conditionally-exec expr : not_expr;
3518 : :
3519 : : Apply this recursively to the condition and the conditionally-exec
3520 : : branch. */
3521 : :
3522 : : struct truth_if_transform {
3523 : : tree *orig_stmt;
3524 : : tree scratch_var;
3525 : : hash_set<tree> *truth_aoif_to_expand;
3526 : : };
3527 : :
3528 : : static tree
3529 : 2398 : expand_one_truth_if (tree *expr, int *do_subtree, void *d)
3530 : : {
3531 : 2398 : truth_if_transform *xform = (truth_if_transform *) d;
3532 : :
3533 : 2398 : bool needs_not = false;
3534 : 2398 : switch (TREE_CODE (*expr))
3535 : : {
3536 : : default: break;
3537 : 7 : case TRUTH_ORIF_EXPR:
3538 : 7 : needs_not = true;
3539 : : /* FALLTHROUGH */
3540 : 17 : case TRUTH_ANDIF_EXPR:
3541 : 17 : {
3542 : 17 : if (!xform->truth_aoif_to_expand->contains (*expr))
3543 : : break;
3544 : :
3545 : 17 : location_t sloc = EXPR_LOCATION (*expr);
3546 : : /* Transform truth expression into a cond expression with
3547 : : * the always-executed arm as the condition.
3548 : : * the conditionally-executed arm as the then clause.
3549 : : * the 'else' clause is fixed: 'true' for ||,'false' for &&. */
3550 : 17 : tree cond = TREE_OPERAND (*expr, 0);
3551 : 17 : tree test1 = TREE_OPERAND (*expr, 1);
3552 : 17 : tree fixed = needs_not ? boolean_true_node : boolean_false_node;
3553 : 10 : if (needs_not)
3554 : 7 : cond = build1 (TRUTH_NOT_EXPR, boolean_type_node, cond);
3555 : 17 : tree cond_expr
3556 : 17 : = build3_loc (sloc, COND_EXPR, boolean_type_node,
3557 : : cond, test1, fixed);
3558 : 17 : *expr = cond_expr;
3559 : 17 : if (tree res = cp_walk_tree (&COND_EXPR_COND (*expr),
3560 : : expand_one_truth_if, d, NULL))
3561 : : return res;
3562 : 17 : if (tree res = cp_walk_tree (&COND_EXPR_THEN (*expr),
3563 : : expand_one_truth_if, d, NULL))
3564 : : return res;
3565 : : /* We've manually processed necessary sub-trees here. */
3566 : 17 : *do_subtree = 0;
3567 : : }
3568 : 17 : break;
3569 : : }
3570 : : return NULL_TREE;
3571 : : }
3572 : :
3573 : : /* Helper that adds a new variable of VAR_TYPE to a bind scope BIND, the
3574 : : name is made up from NAM_ROOT, NAM_VERS. */
3575 : :
3576 : : static tree
3577 : 77 : add_var_to_bind (tree& bind, tree var_type,
3578 : : const char *nam_root, unsigned nam_vers)
3579 : : {
3580 : 77 : tree b_vars = BIND_EXPR_VARS (bind);
3581 : : /* Build a variable to hold the condition, this will be included in the
3582 : : frame as a local var. */
3583 : 77 : char *nam = xasprintf ("__%s_%d", nam_root, nam_vers);
3584 : 77 : tree newvar = build_lang_decl (VAR_DECL, get_identifier (nam), var_type);
3585 : 77 : free (nam);
3586 : 77 : DECL_CHAIN (newvar) = b_vars;
3587 : 77 : BIND_EXPR_VARS (bind) = newvar;
3588 : 77 : return newvar;
3589 : : }
3590 : :
3591 : : /* Helper to build and add if (!cond) break; */
3592 : :
3593 : : static void
3594 : 41 : coro_build_add_if_not_cond_break (tree cond)
3595 : : {
3596 : 41 : tree if_stmt = begin_if_stmt ();
3597 : 41 : tree invert = build1 (TRUTH_NOT_EXPR, boolean_type_node, cond);
3598 : 41 : finish_if_stmt_cond (invert, if_stmt);
3599 : 41 : finish_break_stmt ();
3600 : 41 : finish_then_clause (if_stmt);
3601 : 41 : finish_if_stmt (if_stmt);
3602 : 41 : }
3603 : :
3604 : : /* Tree walk callback to replace continue statements with goto label. */
3605 : : static tree
3606 : 893 : replace_continue (tree *stmt, int *do_subtree, void *d)
3607 : : {
3608 : 893 : tree expr = *stmt;
3609 : 893 : if (TREE_CODE (expr) == CLEANUP_POINT_EXPR)
3610 : 32 : expr = TREE_OPERAND (expr, 0);
3611 : 893 : if (CONVERT_EXPR_P (expr) && VOID_TYPE_P (TREE_TYPE (expr)))
3612 : 32 : expr = TREE_OPERAND (expr, 0);
3613 : 893 : STRIP_NOPS (expr);
3614 : 893 : if (!STATEMENT_CLASS_P (expr))
3615 : : return NULL_TREE;
3616 : :
3617 : 36 : switch (TREE_CODE (expr))
3618 : : {
3619 : : /* Unless it's a special case, just walk the subtrees as usual. */
3620 : : default: return NULL_TREE;
3621 : :
3622 : 8 : case CONTINUE_STMT:
3623 : 8 : {
3624 : 8 : tree *label = (tree *)d;
3625 : 8 : location_t loc = EXPR_LOCATION (expr);
3626 : : /* re-write a continue to goto label. */
3627 : 8 : *stmt = build_stmt (loc, GOTO_EXPR, *label);
3628 : 8 : *do_subtree = 0;
3629 : 8 : return NULL_TREE;
3630 : : }
3631 : :
3632 : : /* Statements that do not require recursion. */
3633 : 16 : case DECL_EXPR:
3634 : 16 : case BREAK_STMT:
3635 : 16 : case GOTO_EXPR:
3636 : 16 : case LABEL_EXPR:
3637 : 16 : case CASE_LABEL_EXPR:
3638 : 16 : case ASM_EXPR:
3639 : : /* These must break recursion. */
3640 : 16 : case FOR_STMT:
3641 : 16 : case WHILE_STMT:
3642 : 16 : case DO_STMT:
3643 : 16 : *do_subtree = 0;
3644 : 16 : return NULL_TREE;
3645 : : }
3646 : : }
3647 : :
3648 : : /* Tree walk callback to analyze, register and pre-process statements that
3649 : : contain await expressions. */
3650 : :
3651 : : static tree
3652 : 209967 : await_statement_walker (tree *stmt, int *do_subtree, void *d)
3653 : : {
3654 : 209967 : tree res = NULL_TREE;
3655 : 209967 : susp_frame_data *awpts = (susp_frame_data *) d;
3656 : :
3657 : : /* Process a statement at a time. */
3658 : 209967 : if (TREE_CODE (*stmt) == BIND_EXPR)
3659 : : {
3660 : : /* For conditional expressions, we might wish to add an artificial var
3661 : : to their containing bind expr. */
3662 : 3369 : vec_safe_push (awpts->bind_stack, *stmt);
3663 : : /* We might need to insert a new bind expression, and want to link it
3664 : : into the correct scope, so keep a note of the current block scope. */
3665 : 3369 : tree blk = BIND_EXPR_BLOCK (*stmt);
3666 : 3369 : vec_safe_push (awpts->block_stack, blk);
3667 : 3369 : res = cp_walk_tree (&BIND_EXPR_BODY (*stmt), await_statement_walker,
3668 : : d, NULL);
3669 : 3369 : awpts->block_stack->pop ();
3670 : 3369 : awpts->bind_stack->pop ();
3671 : 3369 : *do_subtree = 0; /* Done subtrees. */
3672 : 3369 : return res;
3673 : : }
3674 : 206598 : else if (TREE_CODE (*stmt) == STATEMENT_LIST)
3675 : : {
3676 : 43706 : for (tree &s : tsi_range (*stmt))
3677 : : {
3678 : 36271 : res = cp_walk_tree (&s, await_statement_walker,
3679 : : d, NULL);
3680 : 36271 : if (res)
3681 : 209967 : return res;
3682 : : }
3683 : 7435 : *do_subtree = 0; /* Done subtrees. */
3684 : 7435 : return NULL_TREE;
3685 : : }
3686 : :
3687 : : /* We have something to be handled as a single statement. We have to handle
3688 : : a few statements specially where await statements have to be moved out of
3689 : : constructs. */
3690 : 199163 : tree expr = *stmt;
3691 : 199163 : if (TREE_CODE (*stmt) == CLEANUP_POINT_EXPR)
3692 : 16775 : expr = TREE_OPERAND (expr, 0);
3693 : 199163 : STRIP_NOPS (expr);
3694 : :
3695 : 199163 : if (STATEMENT_CLASS_P (expr))
3696 : 24779 : switch (TREE_CODE (expr))
3697 : : {
3698 : : /* Unless it's a special case, just walk the subtrees as usual. */
3699 : : default: return NULL_TREE;
3700 : :
3701 : : /* When we have a conditional expression, which contains one or more
3702 : : await expressions, we have to break the condition out into a
3703 : : regular statement so that the control flow introduced by the await
3704 : : transforms can be implemented. */
3705 : 1862 : case IF_STMT:
3706 : 1862 : {
3707 : 1862 : tree *await_ptr;
3708 : 1862 : hash_set<tree> visited;
3709 : : /* Transform 'if (cond with awaits) then stmt1 else stmt2' into
3710 : : bool cond = cond with awaits.
3711 : : if (cond) then stmt1 else stmt2. */
3712 : 1862 : tree if_stmt = *stmt;
3713 : : /* We treat the condition as if it was a stand-alone statement,
3714 : : to see if there are any await expressions which will be analyzed
3715 : : and registered. */
3716 : 1862 : if (!(cp_walk_tree (&IF_COND (if_stmt),
3717 : : find_any_await, &await_ptr, &visited)))
3718 : : return NULL_TREE; /* Nothing special to do here. */
3719 : :
3720 : 67 : gcc_checking_assert (!awpts->bind_stack->is_empty());
3721 : 67 : tree& bind_expr = awpts->bind_stack->last ();
3722 : 134 : tree newvar = add_var_to_bind (bind_expr, boolean_type_node,
3723 : 67 : "ifcd", awpts->cond_number++);
3724 : 67 : tree insert_list = push_stmt_list ();
3725 : 67 : tree cond_inner = IF_COND (if_stmt);
3726 : 67 : if (TREE_CODE (cond_inner) == CLEANUP_POINT_EXPR)
3727 : 67 : cond_inner = TREE_OPERAND (cond_inner, 0);
3728 : 67 : add_decl_expr (newvar);
3729 : 67 : location_t sloc = EXPR_LOCATION (IF_COND (if_stmt));
3730 : : /* We want to initialize the new variable with the expression
3731 : : that contains the await(s) and potentially also needs to
3732 : : have truth_if expressions expanded. */
3733 : 67 : tree new_s = cp_build_init_expr (sloc, newvar, cond_inner);
3734 : 67 : finish_expr_stmt (new_s);
3735 : 67 : IF_COND (if_stmt) = newvar;
3736 : 67 : add_stmt (if_stmt);
3737 : 67 : *stmt = pop_stmt_list (insert_list);
3738 : : /* So now walk the new statement list. */
3739 : 67 : res = cp_walk_tree (stmt, await_statement_walker, d, NULL);
3740 : 67 : *do_subtree = 0; /* Done subtrees. */
3741 : 67 : return res;
3742 : 1862 : }
3743 : 139 : break;
3744 : 139 : case FOR_STMT:
3745 : 139 : {
3746 : 139 : tree *await_ptr;
3747 : 139 : hash_set<tree> visited;
3748 : : /* for loops only need special treatment if the condition or the
3749 : : iteration expression contain a co_await. */
3750 : 139 : tree for_stmt = *stmt;
3751 : : /* At present, the FE always generates a separate initializer for
3752 : : the FOR_INIT_STMT, when the expression has an await. Check that
3753 : : this assumption holds in the future. */
3754 : 139 : gcc_checking_assert
3755 : : (!(cp_walk_tree (&FOR_INIT_STMT (for_stmt), find_any_await,
3756 : : &await_ptr, &visited)));
3757 : :
3758 : 139 : visited.empty ();
3759 : 139 : bool for_cond_await
3760 : 139 : = cp_walk_tree (&FOR_COND (for_stmt), find_any_await,
3761 : : &await_ptr, &visited);
3762 : :
3763 : 139 : visited.empty ();
3764 : 139 : bool for_expr_await
3765 : 139 : = cp_walk_tree (&FOR_EXPR (for_stmt), find_any_await,
3766 : : &await_ptr, &visited);
3767 : :
3768 : : /* If the condition has an await, then we will need to rewrite the
3769 : : loop as
3770 : : for (init expression;true;iteration expression) {
3771 : : condition = await expression;
3772 : : if (condition)
3773 : : break;
3774 : : ...
3775 : : }
3776 : : */
3777 : 139 : if (for_cond_await)
3778 : : {
3779 : 19 : tree insert_list = push_stmt_list ();
3780 : : /* This will be expanded when the revised body is handled. */
3781 : 19 : coro_build_add_if_not_cond_break (FOR_COND (for_stmt));
3782 : : /* .. add the original for body. */
3783 : 19 : add_stmt (FOR_BODY (for_stmt));
3784 : : /* To make the new for body. */
3785 : 19 : FOR_BODY (for_stmt) = pop_stmt_list (insert_list);
3786 : 19 : FOR_COND (for_stmt) = boolean_true_node;
3787 : : }
3788 : : /* If the iteration expression has an await, it's a bit more
3789 : : tricky.
3790 : : for (init expression;condition;) {
3791 : : ...
3792 : : iteration_expr_label:
3793 : : iteration expression with await;
3794 : : }
3795 : : but, then we will need to re-write any continue statements into
3796 : : 'goto iteration_expr_label:'.
3797 : : */
3798 : 139 : if (for_expr_await)
3799 : : {
3800 : 16 : location_t sloc = EXPR_LOCATION (FOR_EXPR (for_stmt));
3801 : 16 : tree insert_list = push_stmt_list ();
3802 : : /* The original for body. */
3803 : 16 : add_stmt (FOR_BODY (for_stmt));
3804 : 16 : char *buf = xasprintf ("for.iter.expr.%u", awpts->cond_number++);
3805 : 16 : tree it_expr_label
3806 : 16 : = create_named_label_with_ctx (sloc, buf, NULL_TREE);
3807 : 16 : free (buf);
3808 : 16 : add_stmt (build_stmt (sloc, LABEL_EXPR, it_expr_label));
3809 : 16 : tree for_expr = FOR_EXPR (for_stmt);
3810 : : /* Present the iteration expression as a statement. */
3811 : 16 : if (TREE_CODE (for_expr) == CLEANUP_POINT_EXPR)
3812 : 16 : for_expr = TREE_OPERAND (for_expr, 0);
3813 : 16 : STRIP_NOPS (for_expr);
3814 : 16 : finish_expr_stmt (for_expr);
3815 : 16 : FOR_EXPR (for_stmt) = NULL_TREE;
3816 : 16 : FOR_BODY (for_stmt) = pop_stmt_list (insert_list);
3817 : : /* rewrite continue statements to goto label. */
3818 : 16 : hash_set<tree> visited_continue;
3819 : 16 : if ((res = cp_walk_tree (&FOR_BODY (for_stmt),
3820 : : replace_continue, &it_expr_label, &visited_continue)))
3821 : 0 : return res;
3822 : 16 : }
3823 : :
3824 : : /* So now walk the body statement (list), if there were no await
3825 : : expressions, then this handles the original body - and either
3826 : : way we will have finished with this statement. */
3827 : 139 : res = cp_walk_tree (&FOR_BODY (for_stmt),
3828 : : await_statement_walker, d, NULL);
3829 : 139 : *do_subtree = 0; /* Done subtrees. */
3830 : 139 : return res;
3831 : 139 : }
3832 : 14 : break;
3833 : 14 : case WHILE_STMT:
3834 : 14 : {
3835 : : /* We turn 'while (cond with awaits) stmt' into
3836 : : while (true) {
3837 : : if (!(cond with awaits))
3838 : : break;
3839 : : stmt..
3840 : : } */
3841 : 14 : tree *await_ptr;
3842 : 14 : hash_set<tree> visited;
3843 : 14 : tree while_stmt = *stmt;
3844 : 14 : if (!(cp_walk_tree (&WHILE_COND (while_stmt),
3845 : : find_any_await, &await_ptr, &visited)))
3846 : : return NULL_TREE; /* Nothing special to do here. */
3847 : :
3848 : 14 : tree insert_list = push_stmt_list ();
3849 : 14 : coro_build_add_if_not_cond_break (WHILE_COND (while_stmt));
3850 : : /* The original while body. */
3851 : 14 : add_stmt (WHILE_BODY (while_stmt));
3852 : : /* The new while body. */
3853 : 14 : WHILE_BODY (while_stmt) = pop_stmt_list (insert_list);
3854 : 14 : WHILE_COND (while_stmt) = boolean_true_node;
3855 : : /* So now walk the new statement list. */
3856 : 14 : res = cp_walk_tree (&WHILE_BODY (while_stmt),
3857 : : await_statement_walker, d, NULL);
3858 : 14 : *do_subtree = 0; /* Done subtrees. */
3859 : 14 : return res;
3860 : 14 : }
3861 : 12 : break;
3862 : 12 : case DO_STMT:
3863 : 12 : {
3864 : : /* We turn do stmt while (cond with awaits) into:
3865 : : do {
3866 : : stmt..
3867 : : if (!(cond with awaits))
3868 : : break;
3869 : : } while (true); */
3870 : 12 : tree do_stmt = *stmt;
3871 : 12 : tree *await_ptr;
3872 : 12 : hash_set<tree> visited;
3873 : 12 : if (!(cp_walk_tree (&DO_COND (do_stmt),
3874 : : find_any_await, &await_ptr, &visited)))
3875 : : return NULL_TREE; /* Nothing special to do here. */
3876 : :
3877 : 8 : tree insert_list = push_stmt_list ();
3878 : : /* The original do stmt body. */
3879 : 8 : add_stmt (DO_BODY (do_stmt));
3880 : 8 : coro_build_add_if_not_cond_break (DO_COND (do_stmt));
3881 : : /* The new while body. */
3882 : 8 : DO_BODY (do_stmt) = pop_stmt_list (insert_list);
3883 : 8 : DO_COND (do_stmt) = boolean_true_node;
3884 : : /* So now walk the new statement list. */
3885 : 8 : res = cp_walk_tree (&DO_BODY (do_stmt), await_statement_walker,
3886 : : d, NULL);
3887 : 8 : *do_subtree = 0; /* Done subtrees. */
3888 : 8 : return res;
3889 : 12 : }
3890 : 23 : break;
3891 : 23 : case SWITCH_STMT:
3892 : 23 : {
3893 : : /* We turn 'switch (cond with awaits) stmt' into
3894 : : switch_type cond = cond with awaits
3895 : : switch (cond) stmt. */
3896 : 23 : tree sw_stmt = *stmt;
3897 : 23 : tree *await_ptr;
3898 : 23 : hash_set<tree> visited;
3899 : 23 : if (!(cp_walk_tree (&SWITCH_STMT_COND (sw_stmt),
3900 : : find_any_await, &await_ptr, &visited)))
3901 : : return NULL_TREE; /* Nothing special to do here. */
3902 : :
3903 : 10 : gcc_checking_assert (!awpts->bind_stack->is_empty());
3904 : : /* Build a variable to hold the condition, this will be
3905 : : included in the frame as a local var. */
3906 : 10 : tree& bind_expr = awpts->bind_stack->last ();
3907 : 10 : tree sw_type = SWITCH_STMT_TYPE (sw_stmt);
3908 : 20 : tree newvar = add_var_to_bind (bind_expr, sw_type, "swch",
3909 : 10 : awpts->cond_number++);
3910 : 10 : tree insert_list = push_stmt_list ();
3911 : 10 : add_decl_expr (newvar);
3912 : :
3913 : 10 : tree cond_inner = SWITCH_STMT_COND (sw_stmt);
3914 : 10 : if (TREE_CODE (cond_inner) == CLEANUP_POINT_EXPR)
3915 : 10 : cond_inner = TREE_OPERAND (cond_inner, 0);
3916 : 10 : location_t sloc = EXPR_LOCATION (SWITCH_STMT_COND (sw_stmt));
3917 : 10 : tree new_s = cp_build_init_expr (sloc, newvar,
3918 : : cond_inner);
3919 : 10 : finish_expr_stmt (new_s);
3920 : 10 : SWITCH_STMT_COND (sw_stmt) = newvar;
3921 : : /* Now add the switch statement with the condition re-
3922 : : written to use the local var. */
3923 : 10 : add_stmt (sw_stmt);
3924 : 10 : *stmt = pop_stmt_list (insert_list);
3925 : : /* Process the expanded list. */
3926 : 10 : res = cp_walk_tree (stmt, await_statement_walker,
3927 : : d, NULL);
3928 : 10 : *do_subtree = 0; /* Done subtrees. */
3929 : 10 : return res;
3930 : 23 : }
3931 : 1432 : break;
3932 : 1432 : case CO_RETURN_EXPR:
3933 : 1432 : {
3934 : : /* Expand the co_return as per [stmt.return.coroutine]
3935 : : - for co_return;
3936 : : { p.return_void (); goto final_suspend; }
3937 : : - for co_return [void expr];
3938 : : { expr; p.return_void(); goto final_suspend;}
3939 : : - for co_return [non void expr];
3940 : : { p.return_value(expr); goto final_suspend; } */
3941 : 1432 : location_t loc = EXPR_LOCATION (expr);
3942 : 1432 : tree call = TREE_OPERAND (expr, 1);
3943 : 1432 : expr = TREE_OPERAND (expr, 0);
3944 : 1432 : tree ret_list = push_stmt_list ();
3945 : : /* [stmt.return.coroutine], 2.2
3946 : : If expr is present and void, it is placed immediately before
3947 : : the call for return_void; */
3948 : 1432 : if (expr && VOID_TYPE_P (TREE_TYPE (expr)))
3949 : 10 : finish_expr_stmt (expr);
3950 : : /* Insert p.return_{void,value(expr)}. */
3951 : 1432 : finish_expr_stmt (call);
3952 : 1432 : TREE_USED (awpts->fs_label) = 1;
3953 : 1432 : add_stmt (build_stmt (loc, GOTO_EXPR, awpts->fs_label));
3954 : 1432 : *stmt = pop_stmt_list (ret_list);
3955 : 1432 : res = cp_walk_tree (stmt, await_statement_walker, d, NULL);
3956 : : /* Once this is complete, we will have processed subtrees. */
3957 : 1432 : *do_subtree = 0;
3958 : 1432 : return res;
3959 : : }
3960 : 1529 : break;
3961 : 1529 : case HANDLER:
3962 : 1529 : {
3963 : : /* [expr.await] An await-expression shall appear only in a
3964 : : potentially-evaluated expression within the compound-statement
3965 : : of a function-body outside of a handler. */
3966 : 1529 : tree *await_ptr;
3967 : 1529 : hash_set<tree> visited;
3968 : 1529 : if (!(cp_walk_tree (&HANDLER_BODY (expr), find_any_await,
3969 : : &await_ptr, &visited)))
3970 : : return NULL_TREE; /* All OK. */
3971 : 3 : location_t loc = EXPR_LOCATION (*await_ptr);
3972 : 3 : error_at (loc, "await expressions are not permitted in handlers");
3973 : 3 : return NULL_TREE; /* This is going to fail later anyway. */
3974 : 1529 : }
3975 : 174384 : break;
3976 : : }
3977 : 174384 : else if (EXPR_P (expr))
3978 : : {
3979 : 67970 : hash_set<tree> visited;
3980 : 67970 : tree *await_ptr;
3981 : 67970 : if (!(cp_walk_tree (stmt, find_any_await, &await_ptr, &visited)))
3982 : : return NULL_TREE; /* Nothing special to do here. */
3983 : :
3984 : 4033 : visited.empty ();
3985 : 4033 : awpts->saw_awaits = 0;
3986 : 4033 : hash_set<tree> truth_aoif_to_expand;
3987 : 4033 : awpts->truth_aoif_to_expand = &truth_aoif_to_expand;
3988 : 4033 : awpts->needs_truth_if_exp = false;
3989 : 4033 : awpts->has_awaiter_init = false;
3990 : 4033 : if ((res = cp_walk_tree (stmt, analyze_expression_awaits, d, &visited)))
3991 : : return res;
3992 : 4033 : *do_subtree = 0; /* Done subtrees. */
3993 : 4033 : if (!awpts->saw_awaits)
3994 : : return NULL_TREE; /* Nothing special to do here. */
3995 : :
3996 : 4024 : if (awpts->needs_truth_if_exp)
3997 : : {
3998 : : /* If a truth-and/or-if expression has an await expression in the
3999 : : conditionally-taken branch, then it must be rewritten into a
4000 : : regular conditional. */
4001 : 17 : truth_if_transform xf = {stmt, NULL_TREE, &truth_aoif_to_expand};
4002 : 17 : if ((res = cp_walk_tree (stmt, expand_one_truth_if, &xf, NULL)))
4003 : 0 : return res;
4004 : : }
4005 : : /* Process this statement, which contains at least one await expression
4006 : : to 'promote' temporary values to a coroutine frame slot. */
4007 : 4024 : return maybe_promote_temps (stmt, d);
4008 : 72003 : }
4009 : : /* Continue recursion, if needed. */
4010 : : return res;
4011 : : }
4012 : :
4013 : : /* For figuring out what param usage we have. */
4014 : :
4015 : : struct param_frame_data
4016 : : {
4017 : : tree *field_list;
4018 : : hash_map<tree, param_info> *param_uses;
4019 : : hash_set<tree *> *visited;
4020 : : location_t loc;
4021 : : bool param_seen;
4022 : : };
4023 : :
4024 : : /* A tree walk callback that rewrites each parm use to the local variable
4025 : : that represents its copy in the frame. */
4026 : :
4027 : : static tree
4028 : 105857 : rewrite_param_uses (tree *stmt, int *do_subtree ATTRIBUTE_UNUSED, void *d)
4029 : : {
4030 : 105857 : param_frame_data *data = (param_frame_data *) d;
4031 : :
4032 : : /* For lambda closure content, we have to look specifically. */
4033 : 105857 : if (VAR_P (*stmt) && DECL_HAS_VALUE_EXPR_P (*stmt))
4034 : : {
4035 : 644 : tree t = DECL_VALUE_EXPR (*stmt);
4036 : 644 : return cp_walk_tree (&t, rewrite_param_uses, d, NULL);
4037 : : }
4038 : :
4039 : 105213 : if (unevaluated_p (TREE_CODE (*stmt)))
4040 : : {
4041 : : /* No odr-uses in unevaluated operands. */
4042 : 3 : *do_subtree = 0;
4043 : 3 : return NULL_TREE;
4044 : : }
4045 : :
4046 : 105210 : if (TREE_CODE (*stmt) != PARM_DECL)
4047 : : return NULL_TREE;
4048 : :
4049 : : /* If we already saw the containing expression, then we're done. */
4050 : 928 : if (data->visited->add (stmt))
4051 : : return NULL_TREE;
4052 : :
4053 : 928 : bool existed;
4054 : 928 : param_info &parm = data->param_uses->get_or_insert (*stmt, &existed);
4055 : 928 : gcc_checking_assert (existed);
4056 : :
4057 : 928 : *stmt = parm.copy_var;
4058 : 928 : return NULL_TREE;
4059 : : }
4060 : :
4061 : : /* Build up a set of info that determines how each param copy will be
4062 : : handled. We store this in a hash map so that we can access it from
4063 : : a tree walk callback that re-writes the original parameters to their
4064 : : copies. */
4065 : :
4066 : : void
4067 : 1532 : cp_coroutine_transform::analyze_fn_parms ()
4068 : : {
4069 : 1532 : if (!DECL_ARGUMENTS (orig_fn_decl))
4070 : : return;
4071 : :
4072 : : /* Build a hash map with an entry for each param.
4073 : : The key is the param tree.
4074 : : Then we have an entry for the frame field name.
4075 : : Then a cache for the field ref when we come to use it.
4076 : : Then a tree list of the uses.
4077 : : The second two entries start out empty - and only get populated
4078 : : when we see uses. */
4079 : 910 : bool lambda_p = LAMBDA_FUNCTION_P (orig_fn_decl);
4080 : :
4081 : : /* Count the param copies from 1 as per the std. */
4082 : 727 : unsigned parm_num = 1;
4083 : 1681 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
4084 : 954 : ++parm_num, arg = DECL_CHAIN (arg))
4085 : : {
4086 : 954 : bool existed;
4087 : 954 : param_info &parm = param_uses.get_or_insert (arg, &existed);
4088 : 954 : gcc_checking_assert (!existed);
4089 : 954 : parm.body_uses = NULL;
4090 : 954 : tree actual_type = TREE_TYPE (arg);
4091 : 954 : actual_type = complete_type_or_else (actual_type, orig_fn_decl);
4092 : 954 : if (actual_type == NULL_TREE)
4093 : 0 : actual_type = error_mark_node;
4094 : 954 : parm.orig_type = actual_type;
4095 : 954 : parm.by_ref = parm.pt_ref = parm.rv_ref = false;
4096 : 954 : if (TREE_CODE (actual_type) == REFERENCE_TYPE)
4097 : : {
4098 : : /* If the user passes by reference, then we will save the
4099 : : pointer to the original. As noted in
4100 : : [dcl.fct.def.coroutine] / 13, if the lifetime of the
4101 : : referenced item ends and then the coroutine is resumed,
4102 : : we have UB; well, the user asked for it. */
4103 : 131 : if (TYPE_REF_IS_RVALUE (actual_type))
4104 : 41 : parm.rv_ref = true;
4105 : : else
4106 : 90 : parm.pt_ref = true;
4107 : : }
4108 : 823 : else if (TYPE_REF_P (DECL_ARG_TYPE (arg)))
4109 : 80 : parm.by_ref = true;
4110 : :
4111 : 954 : parm.frame_type = actual_type;
4112 : :
4113 : 954 : parm.this_ptr = is_this_parameter (arg);
4114 : 954 : parm.lambda_cobj = lambda_p && DECL_NAME (arg) == closure_identifier;
4115 : :
4116 : 954 : tree name = DECL_NAME (arg);
4117 : 954 : if (!name)
4118 : : {
4119 : 78 : char *buf = xasprintf ("_Coro_q%u___unnamed", parm_num);
4120 : 78 : name = get_identifier (buf);
4121 : 78 : free (buf);
4122 : : }
4123 : 954 : parm.field_id = name;
4124 : 954 : if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (parm.frame_type))
4125 : 80 : parm.trivial_dtor = false;
4126 : : else
4127 : 874 : parm.trivial_dtor = true;
4128 : : }
4129 : : }
4130 : :
4131 : : /* Small helper for the repetitive task of adding a new field to the coro
4132 : : frame type. */
4133 : :
4134 : : static tree
4135 : 16941 : coro_make_frame_entry (tree *field_list, const char *name, tree fld_type,
4136 : : location_t loc)
4137 : : {
4138 : 16941 : tree id = get_identifier (name);
4139 : 16941 : tree decl = build_decl (loc, FIELD_DECL, id, fld_type);
4140 : 16941 : DECL_CHAIN (decl) = *field_list;
4141 : 16941 : *field_list = decl;
4142 : 16941 : return id;
4143 : : }
4144 : :
4145 : : /* A tree-walk callback that processes one bind expression noting local
4146 : : variables, and making a coroutine frame slot available for those that
4147 : : need it, so that they can be 'promoted' across suspension points. */
4148 : :
4149 : : static tree
4150 : 366419 : register_local_var_uses (tree *stmt, int *do_subtree, void *d)
4151 : : {
4152 : 366419 : if (TREE_CODE (*stmt) != BIND_EXPR)
4153 : : return NULL_TREE;
4154 : :
4155 : 7399 : local_vars_frame_data *lvd = (local_vars_frame_data *) d;
4156 : :
4157 : : /* As we enter a bind expression - record the vars there and then recurse.
4158 : : As we exit drop the nest depth.
4159 : : The bind index is a growing count of how many bind indices we've seen.
4160 : : We build a space in the frame for each local var. */
4161 : :
4162 : 7399 : tree lvar;
4163 : 7399 : unsigned serial = 0;
4164 : 24511 : for (lvar = BIND_EXPR_VARS (*stmt); lvar != NULL; lvar = DECL_CHAIN (lvar))
4165 : : {
4166 : 17112 : bool existed;
4167 : 17112 : local_var_info &local_var
4168 : 17112 : = lvd->local_var_uses->get_or_insert (lvar, &existed);
4169 : 17112 : gcc_checking_assert (!existed);
4170 : 17112 : local_var.def_loc = DECL_SOURCE_LOCATION (lvar);
4171 : 17112 : tree lvtype = TREE_TYPE (lvar);
4172 : 17112 : local_var.frame_type = lvtype;
4173 : 17112 : local_var.field_idx = local_var.field_id = NULL_TREE;
4174 : :
4175 : : /* Make sure that we only present vars to the tests below. */
4176 : 17112 : if (TREE_CODE (lvar) != PARM_DECL
4177 : 17112 : && TREE_CODE (lvar) != VAR_DECL)
4178 : 171 : continue;
4179 : :
4180 : : /* We don't move static vars into the frame. */
4181 : 17065 : local_var.is_static = TREE_STATIC (lvar);
4182 : 17065 : if (local_var.is_static)
4183 : 5 : continue;
4184 : :
4185 : 17060 : poly_uint64 size;
4186 : 17063 : if (TREE_CODE (lvtype) == ARRAY_TYPE
4187 : 17060 : && !poly_int_tree_p (DECL_SIZE_UNIT (lvar), &size))
4188 : : {
4189 : 3 : sorry_at (local_var.def_loc, "variable length arrays are not"
4190 : : " yet supported in coroutines");
4191 : : /* Ignore it, this is broken anyway. */
4192 : 3 : continue;
4193 : : }
4194 : :
4195 : 17057 : lvd->local_var_seen = true;
4196 : : /* If this var is a lambda capture proxy, we want to leave it alone,
4197 : : and later rewrite the DECL_VALUE_EXPR to indirect through the
4198 : : frame copy of the pointer to the lambda closure object. */
4199 : 17057 : local_var.is_lambda_capture = is_capture_proxy (lvar);
4200 : 17057 : if (local_var.is_lambda_capture)
4201 : 109 : continue;
4202 : :
4203 : : /* If a variable has a value expression, then that's what needs
4204 : : to be processed. */
4205 : 16948 : local_var.has_value_expr_p = DECL_HAS_VALUE_EXPR_P (lvar);
4206 : 16948 : if (local_var.has_value_expr_p)
4207 : 7 : continue;
4208 : :
4209 : : /* Make names depth+index unique, so that we can support nested
4210 : : scopes with identically named locals and still be able to
4211 : : identify them in the coroutine frame. */
4212 : 16941 : tree lvname = DECL_NAME (lvar);
4213 : 16941 : char *buf = NULL;
4214 : :
4215 : : /* The outermost bind scope contains the artificial variables that
4216 : : we inject to implement the coro state machine. We want to be able
4217 : : to inspect these in debugging. */
4218 : 16941 : if (lvname != NULL_TREE && lvd->nest_depth == 0)
4219 : 11656 : buf = xasprintf ("%s", IDENTIFIER_POINTER (lvname));
4220 : 5237 : else if (lvname != NULL_TREE)
4221 : 5237 : buf = xasprintf ("%s_%u_%u", IDENTIFIER_POINTER (lvname),
4222 : : lvd->nest_depth, lvd->bind_indx);
4223 : : else
4224 : 48 : buf = xasprintf ("_D%u_%u_%u", lvd->nest_depth, lvd->bind_indx,
4225 : : serial++);
4226 : :
4227 : : /* TODO: Figure out if we should build a local type that has any
4228 : : excess alignment or size from the original decl. */
4229 : 16941 : local_var.field_id = coro_make_frame_entry (lvd->field_list, buf,
4230 : : lvtype, lvd->loc);
4231 : 16941 : free (buf);
4232 : : /* We don't walk any of the local var sub-trees, they won't contain
4233 : : any bind exprs. */
4234 : : }
4235 : 7399 : lvd->bind_indx++;
4236 : 7399 : lvd->nest_depth++;
4237 : : /* Ensure we only visit each expression once. */
4238 : 7399 : cp_walk_tree_without_duplicates (&BIND_EXPR_BODY (*stmt),
4239 : : register_local_var_uses, d);
4240 : 7399 : *do_subtree = 0; /* We've done this. */
4241 : 7399 : lvd->nest_depth--;
4242 : 7399 : return NULL_TREE;
4243 : : }
4244 : :
4245 : : /* Build, return FUNCTION_DECL node based on ORIG with a type FN_TYPE which has
4246 : : a single argument of type CORO_FRAME_PTR. Build the actor function if
4247 : : ACTOR_P is true, otherwise the destroy. */
4248 : :
4249 : : static tree
4250 : 3064 : coro_build_actor_or_destroy_function (tree orig, tree fn_type,
4251 : : tree coro_frame_ptr, bool actor_p)
4252 : : {
4253 : 3064 : location_t loc = DECL_SOURCE_LOCATION (orig);
4254 : 3064 : tree fn
4255 : 3064 : = build_lang_decl (FUNCTION_DECL, copy_node (DECL_NAME (orig)), fn_type);
4256 : :
4257 : : /* Allow for locating the ramp (original) function from this one. */
4258 : 3064 : if (!to_ramp)
4259 : 1318 : to_ramp = hash_map<tree, tree>::create_ggc (10);
4260 : 3064 : to_ramp->put (fn, orig);
4261 : :
4262 : 3064 : DECL_CONTEXT (fn) = DECL_CONTEXT (orig);
4263 : 3064 : DECL_SOURCE_LOCATION (fn) = loc;
4264 : 3064 : DECL_ARTIFICIAL (fn) = true;
4265 : 3064 : DECL_INITIAL (fn) = error_mark_node;
4266 : :
4267 : 3064 : tree id = get_identifier ("frame_ptr");
4268 : 3064 : tree fp = build_lang_decl (PARM_DECL, id, coro_frame_ptr);
4269 : 3064 : DECL_ARTIFICIAL (fp) = true;
4270 : 3064 : DECL_CONTEXT (fp) = fn;
4271 : 3064 : DECL_ARG_TYPE (fp) = type_passed_as (coro_frame_ptr);
4272 : 3064 : DECL_ARGUMENTS (fn) = fp;
4273 : :
4274 : : /* Copy selected attributes from the original function. */
4275 : 3064 : TREE_USED (fn) = TREE_USED (orig);
4276 : 3064 : if (DECL_SECTION_NAME (orig))
4277 : 0 : set_decl_section_name (fn, orig);
4278 : : /* Copy any alignment that the FE added. */
4279 : 3064 : if (DECL_ALIGN (orig))
4280 : 3064 : SET_DECL_ALIGN (fn, DECL_ALIGN (orig));
4281 : : /* Copy any alignment the user added. */
4282 : 3064 : DECL_USER_ALIGN (fn) = DECL_USER_ALIGN (orig);
4283 : : /* Apply attributes from the original fn. */
4284 : 3064 : DECL_ATTRIBUTES (fn) = copy_list (DECL_ATTRIBUTES (orig));
4285 : : /* but we do not want ones for contracts. */
4286 : 3064 : remove_contract_attributes (fn);
4287 : :
4288 : : /* A void return. */
4289 : 3064 : tree resdecl = build_decl (loc, RESULT_DECL, 0, void_type_node);
4290 : 3064 : DECL_CONTEXT (resdecl) = fn;
4291 : 3064 : DECL_ARTIFICIAL (resdecl) = 1;
4292 : 3064 : DECL_IGNORED_P (resdecl) = 1;
4293 : 3064 : DECL_RESULT (fn) = resdecl;
4294 : :
4295 : : /* Set up a means to find out if a decl is one of the helpers and, if so,
4296 : : which one. */
4297 : 3064 : if (coroutine_info *info = get_coroutine_info (orig))
4298 : : {
4299 : 3064 : gcc_checking_assert ((actor_p && info->actor_decl == NULL_TREE)
4300 : : || info->destroy_decl == NULL_TREE);
4301 : 3064 : if (actor_p)
4302 : 1532 : info->actor_decl = fn;
4303 : : else
4304 : 1532 : info->destroy_decl = fn;
4305 : : }
4306 : 3064 : return fn;
4307 : : }
4308 : :
4309 : : /* Re-write the body as per [dcl.fct.def.coroutine] / 5. */
4310 : :
4311 : : void
4312 : 1532 : cp_coroutine_transform::wrap_original_function_body ()
4313 : : {
4314 : : /* Avoid the code here attaching a location that makes the debugger jump. */
4315 : 1532 : iloc_sentinel stable_input_loc (fn_start);
4316 : 1532 : location_t loc = UNKNOWN_LOCATION;
4317 : 1532 : input_location = loc;
4318 : :
4319 : : /* This will be our new outer scope. */
4320 : 1532 : tree update_body
4321 : 1532 : = build3_loc (loc, BIND_EXPR, void_type_node, NULL, NULL, NULL);
4322 : 1532 : tree top_block = make_node (BLOCK);
4323 : 1532 : BIND_EXPR_BLOCK (update_body) = top_block;
4324 : 1532 : BIND_EXPR_BODY (update_body) = push_stmt_list ();
4325 : :
4326 : : /* If the function has a top level bind expression, then connect that
4327 : : after first making sure we give it a new block. */
4328 : 1532 : tree first = expr_first (coroutine_body);
4329 : 1532 : if (first && TREE_CODE (first) == BIND_EXPR)
4330 : : {
4331 : 628 : tree block = BIND_EXPR_BLOCK (first);
4332 : 628 : gcc_checking_assert (block);
4333 : 628 : gcc_checking_assert (BLOCK_SUPERCONTEXT (block) == NULL_TREE);
4334 : 628 : gcc_checking_assert (BLOCK_CHAIN (block) == NULL_TREE);
4335 : : /* Replace the top block to avoid issues with locations for args
4336 : : appearing to be in a non-existent place. */
4337 : 628 : tree replace_blk = make_node (BLOCK);
4338 : 628 : BLOCK_VARS (replace_blk) = BLOCK_VARS (block);
4339 : 628 : BLOCK_SUBBLOCKS (replace_blk) = BLOCK_SUBBLOCKS (block);
4340 : 879 : for (tree b = BLOCK_SUBBLOCKS (replace_blk); b; b = BLOCK_CHAIN (b))
4341 : 251 : BLOCK_SUPERCONTEXT (b) = replace_blk;
4342 : 628 : BIND_EXPR_BLOCK (first) = replace_blk;
4343 : : /* The top block has one child, so far, and we have now got a
4344 : : superblock. */
4345 : 628 : BLOCK_SUPERCONTEXT (replace_blk) = top_block;
4346 : 628 : BLOCK_SUBBLOCKS (top_block) = replace_blk;
4347 : 628 : }
4348 : : else
4349 : : {
4350 : : /* We are missing a top level BIND_EXPR. We need one to ensure that we
4351 : : don't shuffle around the coroutine frame and corrupt it. */
4352 : 904 : tree bind_wrap = build3_loc (loc, BIND_EXPR, void_type_node,
4353 : : NULL, NULL, NULL);
4354 : 904 : BIND_EXPR_BODY (bind_wrap) = coroutine_body;
4355 : : /* Ensure we have a block to connect up the scopes. */
4356 : 904 : tree new_blk = make_node (BLOCK);
4357 : 904 : BIND_EXPR_BLOCK (bind_wrap) = new_blk;
4358 : 904 : BLOCK_SUBBLOCKS (top_block) = new_blk;
4359 : 904 : coroutine_body = bind_wrap;
4360 : : }
4361 : :
4362 : : /* Wrap the function body in a try {} catch (...) {} block, if exceptions
4363 : : are enabled. */
4364 : 1532 : tree var_list = NULL_TREE;
4365 : :
4366 : : /* [stmt.return.coroutine] / 3
4367 : : If p.return_void() is a valid expression, flowing off the end of a
4368 : : coroutine is equivalent to a co_return with no operand; otherwise
4369 : : flowing off the end of a coroutine results in undefined behavior. */
4370 : 1532 : tree return_void
4371 : 1532 : = get_coroutine_return_void_expr (orig_fn_decl, loc, false);
4372 : :
4373 : : /* The pointer to the resume function. */
4374 : 1532 : tree resume_fn_ptr
4375 : 1532 : = coro_build_artificial_var (loc, coro_resume_fn_id,
4376 : : act_des_fn_ptr_type, orig_fn_decl, NULL_TREE);
4377 : 1532 : DECL_CHAIN (resume_fn_ptr) = var_list;
4378 : 1532 : var_list = resume_fn_ptr;
4379 : 1532 : add_decl_expr (resume_fn_ptr);
4380 : :
4381 : : /* We will need to be able to set the resume function pointer to nullptr
4382 : : to signal that the coroutine is 'done'. */
4383 : 1532 : tree zero_resume
4384 : 1532 : = build1 (CONVERT_EXPR, act_des_fn_ptr_type, nullptr_node);
4385 : :
4386 : : /* The pointer to the destroy function. */
4387 : 1532 : tree var
4388 : 1532 : = coro_build_artificial_var (loc, coro_destroy_fn_id,
4389 : : act_des_fn_ptr_type, orig_fn_decl, NULL_TREE);
4390 : 1532 : DECL_CHAIN (var) = var_list;
4391 : 1532 : var_list = var;
4392 : 1532 : add_decl_expr (var);
4393 : :
4394 : : /* The promise was created on demand when parsing we now link it into
4395 : : our scope. */
4396 : 1532 : tree promise = get_coroutine_promise_proxy (orig_fn_decl);
4397 : 1532 : DECL_CONTEXT (promise) = orig_fn_decl;
4398 : 1532 : DECL_SOURCE_LOCATION (promise) = loc;
4399 : 1532 : DECL_CHAIN (promise) = var_list;
4400 : 1532 : var_list = promise;
4401 : 1532 : add_decl_expr (promise);
4402 : :
4403 : : /* We need a handle to this coroutine, which is passed to every
4404 : : await_suspend(). This was created on demand when parsing we now link it
4405 : : into our scope. */
4406 : 1532 : var = get_coroutine_self_handle_proxy (orig_fn_decl);
4407 : 1532 : DECL_CONTEXT (var) = orig_fn_decl;
4408 : 1532 : DECL_SOURCE_LOCATION (var) = loc;
4409 : 1532 : DECL_CHAIN (var) = var_list;
4410 : 1532 : var_list = var;
4411 : 1532 : add_decl_expr (var);
4412 : :
4413 : : /* If we have function parms, then these will be copied to the coroutine
4414 : : frame as per [dcl.fct.def.coroutine] / 13.
4415 : : Here, we create a local (proxy) variable for each parm, since the original
4416 : : parms will be out of scope once the ramp has finished. The proxy vars will
4417 : : get DECL_VALUE_EXPRs pointing to the frame copies, so that we can interact
4418 : : with them in the debugger. */
4419 : 1532 : if (DECL_ARGUMENTS (orig_fn_decl))
4420 : : {
4421 : : /* Add a local var for each parm. */
4422 : 1681 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
4423 : 954 : arg = DECL_CHAIN (arg))
4424 : : {
4425 : 954 : param_info *parm_i = param_uses.get (arg);
4426 : 954 : gcc_checking_assert (parm_i);
4427 : 954 : parm_i->copy_var
4428 : 954 : = build_lang_decl (VAR_DECL, parm_i->field_id, TREE_TYPE (arg));
4429 : 954 : DECL_SOURCE_LOCATION (parm_i->copy_var) = DECL_SOURCE_LOCATION (arg);
4430 : 954 : DECL_CONTEXT (parm_i->copy_var) = orig_fn_decl;
4431 : 954 : DECL_ARTIFICIAL (parm_i->copy_var) = true;
4432 : 954 : DECL_CHAIN (parm_i->copy_var) = var_list;
4433 : 954 : var_list = parm_i->copy_var;
4434 : 954 : add_decl_expr (parm_i->copy_var);
4435 : : }
4436 : :
4437 : : /* Now replace all uses of the parms in the function body with the proxy
4438 : : vars. We want to this to apply to every instance of param's use, so
4439 : : don't include a 'visited' hash_set on the tree walk, however we will
4440 : : arrange to visit each containing expression only once. */
4441 : 727 : hash_set<tree *> visited;
4442 : 727 : param_frame_data param_data = {NULL, ¶m_uses,
4443 : 727 : &visited, loc, false};
4444 : 727 : cp_walk_tree (&coroutine_body, rewrite_param_uses, ¶m_data, NULL);
4445 : 727 : }
4446 : :
4447 : : /* We create a resume index, this is initialized in the ramp. */
4448 : 1532 : resume_idx_var
4449 : 1532 : = coro_build_artificial_var (loc, coro_resume_index_id,
4450 : : short_unsigned_type_node, orig_fn_decl,
4451 : : NULL_TREE);
4452 : 1532 : DECL_CHAIN (resume_idx_var) = var_list;
4453 : 1532 : var_list = resume_idx_var;
4454 : 1532 : add_decl_expr (resume_idx_var);
4455 : :
4456 : : /* If the coroutine has a frame that needs to be freed, this will be set by
4457 : : the ramp. */
4458 : 1532 : var = coro_build_artificial_var (fn_start, coro_frame_needs_free_id,
4459 : : boolean_type_node, orig_fn_decl, NULL_TREE);
4460 : 1532 : DECL_CHAIN (var) = var_list;
4461 : 1532 : var_list = var;
4462 : 1532 : add_decl_expr (var);
4463 : :
4464 : 1532 : if (flag_exceptions)
4465 : : {
4466 : : /* Build promise.unhandled_exception(); */
4467 : 1510 : tree ueh
4468 : 1510 : = coro_build_promise_expression (orig_fn_decl, promise,
4469 : : coro_unhandled_exception_identifier,
4470 : : fn_start, NULL, /*musthave=*/true);
4471 : : /* Create and initialize the initial-await-resume-called variable per
4472 : : [dcl.fct.def.coroutine] / 5.3. */
4473 : 1510 : tree i_a_r_c
4474 : 1510 : = coro_build_artificial_var (loc, coro_frame_i_a_r_c_id,
4475 : : boolean_type_node, orig_fn_decl,
4476 : : NULL_TREE);
4477 : 1510 : DECL_CHAIN (i_a_r_c) = var_list;
4478 : 1510 : var_list = i_a_r_c;
4479 : 1510 : add_decl_expr (i_a_r_c);
4480 : : /* Start the try-catch. */
4481 : 1510 : tree tcb = build_stmt (loc, TRY_BLOCK, NULL_TREE, NULL_TREE);
4482 : 1510 : add_stmt (tcb);
4483 : 1510 : TRY_STMTS (tcb) = push_stmt_list ();
4484 : : /* Add the initial await to the start of the user-authored function. */
4485 : 1510 : finish_expr_stmt (initial_await);
4486 : : /* Append the original function body. */
4487 : 1510 : add_stmt (coroutine_body);
4488 : 1510 : if (return_void)
4489 : 597 : add_stmt (return_void);
4490 : 1510 : TRY_STMTS (tcb) = pop_stmt_list (TRY_STMTS (tcb));
4491 : 1510 : TRY_HANDLERS (tcb) = push_stmt_list ();
4492 : : /* Mimic what the parser does for the catch. */
4493 : 1510 : tree handler = begin_handler ();
4494 : 1510 : finish_handler_parms (NULL_TREE, handler); /* catch (...) */
4495 : :
4496 : : /* Get the initial await resume called value. */
4497 : 1510 : tree not_iarc_if = begin_if_stmt ();
4498 : 1510 : tree not_iarc = build1_loc (loc, TRUTH_NOT_EXPR,
4499 : : boolean_type_node, i_a_r_c);
4500 : 1510 : finish_if_stmt_cond (not_iarc, not_iarc_if);
4501 : : /* If the initial await resume called value is false, rethrow... */
4502 : 1510 : tree rethrow = build_throw (loc, NULL_TREE, tf_warning_or_error);
4503 : 1510 : suppress_warning (rethrow);
4504 : 1510 : finish_expr_stmt (rethrow);
4505 : 1510 : finish_then_clause (not_iarc_if);
4506 : 1510 : finish_if_stmt (not_iarc_if);
4507 : : /* ... else call the promise unhandled exception method
4508 : : but first we set done = true and the resume index to 0.
4509 : : If the unhandled exception method returns, then we continue
4510 : : to the final await expression (which duplicates the clearing of
4511 : : the field). */
4512 : 1510 : tree r = build2_loc (loc, MODIFY_EXPR, act_des_fn_ptr_type, resume_fn_ptr,
4513 : : zero_resume);
4514 : 1510 : finish_expr_stmt (r);
4515 : 1510 : tree short_zero = build_int_cst (short_unsigned_type_node, 0);
4516 : 1510 : r = build2 (MODIFY_EXPR, short_unsigned_type_node, resume_idx_var,
4517 : : short_zero);
4518 : 1510 : finish_expr_stmt (r);
4519 : 1510 : finish_expr_stmt (ueh);
4520 : 1510 : finish_handler (handler);
4521 : 1510 : TRY_HANDLERS (tcb) = pop_stmt_list (TRY_HANDLERS (tcb));
4522 : : }
4523 : : else
4524 : : {
4525 : 22 : if (pedantic)
4526 : : {
4527 : : /* We still try to look for the promise method and warn if it's not
4528 : : present. */
4529 : 18 : tree ueh_meth
4530 : 18 : = lookup_promise_method (orig_fn_decl,
4531 : : coro_unhandled_exception_identifier,
4532 : : fn_start, /*musthave=*/false);
4533 : 18 : if (!ueh_meth || ueh_meth == error_mark_node)
4534 : 6 : warning_at (fn_start, 0, "no member named %qE in %qT",
4535 : : coro_unhandled_exception_identifier,
4536 : : get_coroutine_promise_type (orig_fn_decl));
4537 : : }
4538 : : /* Else we don't check and don't care if the method is missing..
4539 : : just add the initial suspend, function and return. */
4540 : 22 : finish_expr_stmt (initial_await);
4541 : : /* Append the original function body. */
4542 : 22 : add_stmt (coroutine_body);
4543 : 22 : if (return_void)
4544 : 19 : add_stmt (return_void);
4545 : : }
4546 : :
4547 : : /* co_return branches to the final_suspend label, so declare that now. */
4548 : 1532 : fs_label
4549 : 1532 : = create_named_label_with_ctx (loc, "final.suspend", NULL_TREE);
4550 : 1532 : add_stmt (build_stmt (loc, LABEL_EXPR, fs_label));
4551 : :
4552 : : /* Before entering the final suspend point, we signal that this point has
4553 : : been reached by setting the resume function pointer to zero (this is
4554 : : what the 'done()' builtin tests) as per the current ABI. */
4555 : 1532 : zero_resume = build2_loc (loc, MODIFY_EXPR, act_des_fn_ptr_type,
4556 : : resume_fn_ptr, zero_resume);
4557 : 1532 : finish_expr_stmt (zero_resume);
4558 : 1532 : finish_expr_stmt (final_await);
4559 : :
4560 : 1532 : BIND_EXPR_BODY (update_body) = pop_stmt_list (BIND_EXPR_BODY (update_body));
4561 : 1532 : BIND_EXPR_VARS (update_body) = nreverse (var_list);
4562 : 1532 : BLOCK_VARS (top_block) = BIND_EXPR_VARS (update_body);
4563 : :
4564 : 1532 : coroutine_body = update_body;
4565 : 1532 : }
4566 : :
4567 : : /* Extract the body of the function we are going to outline, leaving
4568 : : to original function decl ready to build the ramp. */
4569 : :
4570 : : static tree
4571 : 1595 : split_coroutine_body_from_ramp (tree fndecl)
4572 : : {
4573 : : /* Sanity-check and punt if we have a nonsense tree because of earlier
4574 : : parse errors, perhaps. */
4575 : 1595 : if (!current_binding_level
4576 : 1595 : || current_binding_level->kind != sk_function_parms)
4577 : : return NULL_TREE;
4578 : :
4579 : : /* Once we've tied off the original user-authored body in fn_body.
4580 : : Start the replacement synthesized ramp body. */
4581 : :
4582 : 1595 : tree body;
4583 : 1595 : if (use_eh_spec_block (fndecl))
4584 : : {
4585 : 360 : body = pop_stmt_list (TREE_OPERAND (current_eh_spec_block, 0));
4586 : 360 : TREE_OPERAND (current_eh_spec_block, 0) = push_stmt_list ();
4587 : : }
4588 : : else
4589 : : {
4590 : 1235 : body = pop_stmt_list (DECL_SAVED_TREE (fndecl));
4591 : 1235 : DECL_SAVED_TREE (fndecl) = push_stmt_list ();
4592 : : }
4593 : :
4594 : : /* We can't validly get here with an empty statement list, since there's no
4595 : : way for the FE to decide it's a coroutine in the absence of any code. */
4596 : 1595 : gcc_checking_assert (body != NULL_TREE);
4597 : :
4598 : : /* If we have an empty or erroneous function body, do not try to transform it
4599 : : since that would potentially wrap errors. */
4600 : 1595 : tree body_start = expr_first (body);
4601 : 1595 : if (body_start == NULL_TREE || body_start == error_mark_node)
4602 : : {
4603 : : /* Restore the original state. */
4604 : 63 : add_stmt (body);
4605 : 63 : return NULL_TREE;
4606 : : }
4607 : : return body;
4608 : : }
4609 : :
4610 : : /* Build the expression to allocate the coroutine frame according to the
4611 : : rules of [dcl.fct.def.coroutine] / 9. */
4612 : :
4613 : : static tree
4614 : 1529 : build_coroutine_frame_alloc_expr (tree promise_type, tree orig_fn_decl,
4615 : : location_t fn_start, tree grooaf,
4616 : : hash_map<tree, param_info> *param_uses,
4617 : : tree frame_size)
4618 : : {
4619 : : /* Allocate the frame, this has several possibilities:
4620 : : [dcl.fct.def.coroutine] / 9 (part 1)
4621 : : The allocation function’s name is looked up in the scope of the promise
4622 : : type. It is not a failure for it to be absent see part 4, below. */
4623 : :
4624 : 1529 : tree nwname = ovl_op_identifier (false, NEW_EXPR);
4625 : 1529 : tree new_fn_call = NULL_TREE;
4626 : 1529 : tree dummy_promise
4627 : 1529 : = build_dummy_object (get_coroutine_promise_type (orig_fn_decl));
4628 : :
4629 : 1529 : if (TYPE_HAS_NEW_OPERATOR (promise_type))
4630 : : {
4631 : 141 : tree fns = lookup_promise_method (orig_fn_decl, nwname, fn_start,
4632 : : /*musthave=*/true);
4633 : : /* [dcl.fct.def.coroutine] / 9 (part 2)
4634 : : If the lookup finds an allocation function in the scope of the promise
4635 : : type, overload resolution is performed on a function call created by
4636 : : assembling an argument list. The first argument is the amount of space
4637 : : requested, and has type std::size_t. The lvalues p1...pn are the
4638 : : succeeding arguments.. */
4639 : 141 : vec<tree, va_gc> *args = make_tree_vector ();
4640 : 141 : vec_safe_push (args, frame_size); /* Space needed. */
4641 : :
4642 : 251 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
4643 : 110 : arg = DECL_CHAIN (arg))
4644 : : {
4645 : 110 : param_info *parm_i = param_uses->get (arg);
4646 : 110 : gcc_checking_assert (parm_i);
4647 : 110 : if (parm_i->this_ptr || parm_i->lambda_cobj)
4648 : : {
4649 : : /* We pass a reference to *this to the allocator lookup. */
4650 : : /* It's unsafe to use the cp_ version here since current_class_ref
4651 : : might've gotten clobbered earlier during rewrite_param_uses. */
4652 : 4 : tree this_ref = build_fold_indirect_ref (arg);
4653 : 4 : vec_safe_push (args, this_ref);
4654 : 4 : }
4655 : : else
4656 : 106 : vec_safe_push (args, convert_from_reference (arg));
4657 : : }
4658 : :
4659 : : /* Note the function selected; we test to see if it's NOTHROW. */
4660 : 141 : tree func;
4661 : : /* Failure is not an error for this attempt. */
4662 : 141 : new_fn_call = build_new_method_call (dummy_promise, fns, &args, NULL,
4663 : : LOOKUP_NORMAL, &func, tf_none);
4664 : 141 : release_tree_vector (args);
4665 : :
4666 : 141 : if (new_fn_call == error_mark_node)
4667 : : {
4668 : : /* [dcl.fct.def.coroutine] / 9 (part 3)
4669 : : If no viable function is found, overload resolution is performed
4670 : : again on a function call created by passing just the amount of
4671 : : space required as an argument of type std::size_t. */
4672 : 47 : args = make_tree_vector_single (frame_size); /* Space needed. */
4673 : 47 : new_fn_call = build_new_method_call (dummy_promise, fns, &args,
4674 : : NULL_TREE, LOOKUP_NORMAL, &func,
4675 : : tf_none);
4676 : 47 : release_tree_vector (args);
4677 : : }
4678 : :
4679 : : /* However, if the promise provides an operator new, then one of these
4680 : : two options must be available. */
4681 : 141 : if (new_fn_call == error_mark_node)
4682 : : {
4683 : 3 : error_at (fn_start, "%qE is provided by %qT but is not usable with"
4684 : : " the function signature %qD", nwname, promise_type,
4685 : : orig_fn_decl);
4686 : 6 : return error_mark_node;
4687 : : }
4688 : 138 : else if (grooaf && !TYPE_NOTHROW_P (TREE_TYPE (func)))
4689 : : {
4690 : 3 : error_at (fn_start, "%qE is provided by %qT but %qE is not marked"
4691 : : " %<throw()%> or %<noexcept%>", grooaf, promise_type, nwname);
4692 : 3 : return error_mark_node;
4693 : : }
4694 : 135 : else if (!grooaf && TYPE_NOTHROW_P (TREE_TYPE (func)))
4695 : 3 : warning_at (fn_start, 0, "%qE is marked %<throw()%> or %<noexcept%> but"
4696 : : " no usable %<get_return_object_on_allocation_failure%>"
4697 : : " is provided by %qT", nwname, promise_type);
4698 : : }
4699 : : else /* No operator new in the promise. */
4700 : : {
4701 : : /* [dcl.fct.def.coroutine] / 9 (part 4)
4702 : : If this lookup fails, the allocation function’s name is looked up in
4703 : : the global scope. */
4704 : :
4705 : 1388 : vec<tree, va_gc> *args;
4706 : : /* build_operator_new_call () will insert size needed as element 0 of
4707 : : this, and we might need to append the std::nothrow constant. */
4708 : 1388 : vec_alloc (args, 2);
4709 : 1388 : if (grooaf)
4710 : : {
4711 : : /* [dcl.fct.def.coroutine] / 10 (part 2)
4712 : : If any declarations (of the get return on allocation fail) are
4713 : : found, then the result of a call to an allocation function used
4714 : : to obtain storage for the coroutine state is assumed to return
4715 : : nullptr if it fails to obtain storage and, if a global allocation
4716 : : function is selected, the ::operator new(size_t, nothrow_t) form
4717 : : is used. The allocation function used in this case shall have a
4718 : : non-throwing noexcept-specification. So we need std::nothrow. */
4719 : 13 : tree std_nt = lookup_qualified_name (std_node,
4720 : : get_identifier ("nothrow"),
4721 : : LOOK_want::NORMAL,
4722 : 13 : /*complain=*/true);
4723 : 13 : if (!std_nt || std_nt == error_mark_node)
4724 : : {
4725 : : /* Something is seriously wrong, punt. */
4726 : 3 : error_at (fn_start, "%qE is provided by %qT but %<std::nothrow%>"
4727 : : " cannot be found", grooaf, promise_type);
4728 : 3 : return error_mark_node;
4729 : : }
4730 : 10 : vec_safe_push (args, std_nt);
4731 : : }
4732 : :
4733 : : /* If we get to this point, we must succeed in looking up the global
4734 : : operator new for the params provided. Since we are not setting
4735 : : size_check or cookie, we expect frame_size to be unaltered. */
4736 : 1385 : tree cookie = NULL;
4737 : 1385 : new_fn_call = build_operator_new_call (nwname, &args, &frame_size,
4738 : : &cookie, /*align_arg=*/NULL,
4739 : : /*size_check=*/NULL, /*fn=*/NULL,
4740 : : tf_warning_or_error);
4741 : 1385 : release_tree_vector (args);
4742 : : }
4743 : : return new_fn_call;
4744 : : }
4745 : :
4746 : : /* Build an expression to delete the coroutine state frame. */
4747 : :
4748 : : static tree
4749 : 3031 : build_coroutine_frame_delete_expr (tree coro_fp, tree frame_size,
4750 : : tree promise_type, location_t loc)
4751 : : {
4752 : : /* Cast the frame pointer to a pointer to promise so that the build op
4753 : : delete call will search the promise. */
4754 : 3031 : tree pptr_type = build_pointer_type (promise_type);
4755 : 3031 : tree frame_arg = build1_loc (loc, CONVERT_EXPR, pptr_type, coro_fp);
4756 : : /* [dcl.fct.def.coroutine] / 12 sentence 3:
4757 : : If both a usual deallocation function with only a pointer parameter and
4758 : : a usual deallocation function with both a pointer parameter and a size
4759 : : parameter are found, then the selected deallocation function shall be the
4760 : : one with two parameters. */
4761 : 3031 : tree del_coro_fr
4762 : 3031 : = build_coroutine_op_delete_call (DELETE_EXPR, frame_arg, frame_size,
4763 : : /*global_p=*/false, /*placement=*/NULL,
4764 : : /*alloc_fn=*/NULL, tf_warning_or_error);
4765 : 3031 : if (!del_coro_fr || del_coro_fr == error_mark_node)
4766 : 3 : return error_mark_node;
4767 : : return del_coro_fr;
4768 : : }
4769 : :
4770 : : /* Build the ramp function.
4771 : : Here we take the original function definition which has now had its body
4772 : : removed, and use it as the declaration of the ramp which both replaces the
4773 : : user's written function at call sites, and is responsible for starting
4774 : : the coroutine it defined.
4775 : : returns false on error.
4776 : :
4777 : : We should arrive here with the state of the compiler as if we had just
4778 : : executed start_preparsed_function(). */
4779 : :
4780 : : bool
4781 : 1532 : cp_coroutine_transform::build_ramp_function ()
4782 : : {
4783 : 1532 : gcc_checking_assert (current_binding_level
4784 : : && current_binding_level->kind == sk_function_parms);
4785 : :
4786 : : /* This is completely synthetic code, if we find an issue then we have not
4787 : : much chance to point at the most useful place in the user's code. In
4788 : : lieu of this use the function start - so at least the diagnostic relates
4789 : : to something that the user can inspect. */
4790 : 1532 : iloc_sentinel saved_position (fn_start);
4791 : 1532 : location_t loc = fn_start;
4792 : :
4793 : 1532 : tree promise_type = get_coroutine_promise_type (orig_fn_decl);
4794 : 1532 : tree fn_return_type = TREE_TYPE (TREE_TYPE (orig_fn_decl));
4795 : 1532 : bool void_ramp_p = VOID_TYPE_P (fn_return_type);
4796 : : /* We know there was no return statement, that is intentional. */
4797 : 1532 : suppress_warning (orig_fn_decl, OPT_Wreturn_type);
4798 : :
4799 : : /* [dcl.fct.def.coroutine] / 10 (part1)
4800 : : The unqualified-id get_return_object_on_allocation_failure is looked up
4801 : : in the scope of the promise type by class member access lookup. */
4802 : :
4803 : : /* We don't require this, but, if the lookup succeeds, then the function
4804 : : must be usable, punt if it is not. */
4805 : 1532 : tree grooaf_meth
4806 : 1532 : = lookup_promise_method (orig_fn_decl,
4807 : : coro_gro_on_allocation_fail_identifier, loc,
4808 : : /*musthave*/ false);
4809 : 1532 : tree grooaf = NULL_TREE;
4810 : 1532 : tree dummy_promise
4811 : 3064 : = build_dummy_object (get_coroutine_promise_type (orig_fn_decl));
4812 : 1532 : if (grooaf_meth && grooaf_meth != error_mark_node)
4813 : : {
4814 : 39 : grooaf
4815 : 39 : = coro_build_promise_expression (orig_fn_decl, dummy_promise,
4816 : : coro_gro_on_allocation_fail_identifier,
4817 : : fn_start, NULL, /*musthave=*/false);
4818 : :
4819 : : /* That should succeed. */
4820 : 39 : if (!grooaf || grooaf == error_mark_node)
4821 : : {
4822 : 3 : error_at (fn_start, "%qE is provided by %qT but is not usable with"
4823 : : " the function %qD", coro_gro_on_allocation_fail_identifier,
4824 : : promise_type, orig_fn_decl);
4825 : 3 : return false;
4826 : : }
4827 : : }
4828 : :
4829 : : /* Check early for usable allocator/deallocator, without which we cannot
4830 : : build a useful ramp; early exit if they are not available or usable. */
4831 : :
4832 : 1529 : frame_size = TYPE_SIZE_UNIT (frame_type);
4833 : :
4834 : : /* Make a var to represent the frame pointer early. */
4835 : 1529 : tree coro_fp = coro_build_artificial_var (loc, "_Coro_frameptr",
4836 : : frame_ptr_type, orig_fn_decl,
4837 : : NULL_TREE);
4838 : :
4839 : 1529 : tree new_fn_call
4840 : 1529 : = build_coroutine_frame_alloc_expr (promise_type, orig_fn_decl, fn_start,
4841 : : grooaf, ¶m_uses, frame_size);
4842 : :
4843 : : /* We must have a useable allocator to proceed. */
4844 : 1529 : if (!new_fn_call || new_fn_call == error_mark_node)
4845 : : return false;
4846 : :
4847 : : /* Likewise, we need the DTOR to delete the frame. */
4848 : 1520 : tree delete_frame_call
4849 : 1520 : = build_coroutine_frame_delete_expr (coro_fp, frame_size, promise_type,
4850 : : fn_start);
4851 : 1520 : if (!delete_frame_call || delete_frame_call == error_mark_node)
4852 : : return false;
4853 : :
4854 : : /* At least verify we can lookup the get return object method. */
4855 : 1517 : tree get_ro_meth
4856 : 1517 : = lookup_promise_method (orig_fn_decl,
4857 : : coro_get_return_object_identifier, loc,
4858 : : /*musthave*/ true);
4859 : 1517 : if (!get_ro_meth || get_ro_meth == error_mark_node)
4860 : : return false;
4861 : :
4862 : : /* So now construct the Ramp: */
4863 : :
4864 : 1514 : tree ramp_fnbody = begin_compound_stmt (BCS_FN_BODY);
4865 : 1514 : coro_fp = pushdecl (coro_fp);
4866 : 1514 : add_decl_expr (coro_fp);
4867 : :
4868 : : /* Build the frame. */
4869 : :
4870 : : /* The CO_FRAME internal function is a mechanism to allow the middle end
4871 : : to adjust the allocation in response to optimizations. We provide the
4872 : : current conservative estimate of the frame size (as per the current)
4873 : : computed layout. */
4874 : :
4875 : 1514 : tree resizeable
4876 : 1514 : = build_call_expr_internal_loc (loc, IFN_CO_FRAME, size_type_node, 2,
4877 : : frame_size,
4878 : : build_zero_cst (frame_ptr_type));
4879 : 1514 : CALL_EXPR_ARG (new_fn_call, 0) = resizeable;
4880 : 1514 : tree allocated = build1 (CONVERT_EXPR, frame_ptr_type, new_fn_call);
4881 : 1514 : tree r = cp_build_init_expr (coro_fp, allocated);
4882 : 1514 : finish_expr_stmt (r);
4883 : :
4884 : : /* If the user provided a method to return an object on alloc fail, then
4885 : : check the returned pointer and call the func if it's null.
4886 : : Otherwise, no check, and we fail for noexcept/fno-exceptions cases. */
4887 : :
4888 : 1514 : if (grooaf)
4889 : : {
4890 : : /* [dcl.fct.def.coroutine] / 10 (part 3)
4891 : : If the allocation function returns nullptr,the coroutine returns
4892 : : control to the caller of the coroutine and the return value is
4893 : : obtained by a call to T::get_return_object_on_allocation_failure(),
4894 : : where T is the promise type. */
4895 : 30 : tree if_stmt = begin_if_stmt ();
4896 : 30 : tree cond = build1 (CONVERT_EXPR, frame_ptr_type, nullptr_node);
4897 : 30 : cond = build2 (EQ_EXPR, boolean_type_node, coro_fp, cond);
4898 : 30 : finish_if_stmt_cond (cond, if_stmt);
4899 : 30 : r = NULL_TREE;
4900 : 30 : if (void_ramp_p)
4901 : : /* Execute the get-return-object-on-alloc-fail call... */
4902 : 0 : finish_expr_stmt (grooaf);
4903 : : else
4904 : : /* Get the fallback return object. */
4905 : : r = grooaf;
4906 : 30 : finish_return_stmt (r);
4907 : 30 : finish_then_clause (if_stmt);
4908 : 30 : finish_if_stmt (if_stmt);
4909 : : }
4910 : :
4911 : : /* Dereference the frame pointer, to use in member access code. */
4912 : 1514 : tree deref_fp
4913 : 1514 : = cp_build_indirect_ref (loc, coro_fp, RO_UNARY_STAR, tf_warning_or_error);
4914 : :
4915 : : /* For now, once allocation has succeeded we always assume that this needs
4916 : : destruction, there's no impl. for frame allocation elision. */
4917 : 1514 : tree frame_needs_free
4918 : 1514 : = coro_build_and_push_artificial_var_with_dve (loc,
4919 : : coro_frame_needs_free_id,
4920 : : boolean_type_node,
4921 : : orig_fn_decl,
4922 : : boolean_true_node,
4923 : : deref_fp);
4924 : : /* Although it appears to be unused here the frame entry is needed and we
4925 : : just set it true. */
4926 : 1514 : TREE_USED (frame_needs_free) = true;
4927 : :
4928 : 1514 : tree iarc_x = NULL_TREE;
4929 : 1514 : tree coro_before_return = NULL_TREE;
4930 : 1514 : if (flag_exceptions)
4931 : : {
4932 : 1492 : coro_before_return
4933 : 1492 : = coro_build_and_push_artificial_var (loc, "_Coro_before_return",
4934 : : boolean_type_node, orig_fn_decl,
4935 : : boolean_true_node);
4936 : 1492 : iarc_x
4937 : 1492 : = coro_build_and_push_artificial_var_with_dve (loc,
4938 : : coro_frame_i_a_r_c_id,
4939 : : boolean_type_node,
4940 : : orig_fn_decl,
4941 : : boolean_false_node,
4942 : : deref_fp);
4943 : 1492 : tree frame_cleanup = push_stmt_list ();
4944 : 1492 : tree do_fr_cleanup
4945 : 1492 : = build1_loc (loc, TRUTH_NOT_EXPR, boolean_type_node, iarc_x);
4946 : 1492 : do_fr_cleanup = build2_loc (loc, TRUTH_ANDIF_EXPR, boolean_type_node,
4947 : : coro_before_return, do_fr_cleanup);
4948 : 1492 : r = build3 (COND_EXPR, void_type_node, do_fr_cleanup,
4949 : : delete_frame_call, void_node);
4950 : 1492 : finish_expr_stmt (r);
4951 : 1492 : push_cleanup (coro_fp, pop_stmt_list (frame_cleanup), /*eh_only*/true);
4952 : : }
4953 : :
4954 : : /* Put the resumer and destroyer functions in. */
4955 : :
4956 : 1514 : tree actor_addr = build1 (ADDR_EXPR, act_des_fn_ptr_type, resumer);
4957 : 1514 : coro_build_and_push_artificial_var_with_dve (loc, coro_resume_fn_id,
4958 : : act_des_fn_ptr_type,
4959 : : orig_fn_decl,
4960 : : actor_addr, deref_fp);
4961 : :
4962 : 1514 : tree destroy_addr = build1 (ADDR_EXPR, act_des_fn_ptr_type, destroyer);
4963 : 1514 : coro_build_and_push_artificial_var_with_dve (loc, coro_destroy_fn_id,
4964 : : act_des_fn_ptr_type,
4965 : : orig_fn_decl,
4966 : : destroy_addr, deref_fp);
4967 : :
4968 : : /* [dcl.fct.def.coroutine] /13
4969 : : When a coroutine is invoked, a copy is created for each coroutine
4970 : : parameter. Each such copy is an object with automatic storage duration
4971 : : that is direct-initialized from an lvalue referring to the corresponding
4972 : : parameter if the parameter is an lvalue reference, and from an xvalue
4973 : : referring to it otherwise. A reference to a parameter in the function-
4974 : : body of the coroutine and in the call to the coroutine promise
4975 : : constructor is replaced by a reference to its copy. */
4976 : :
4977 : 1514 : vec<tree, va_gc> *promise_args = NULL; /* So that we can adjust refs. */
4978 : :
4979 : : /* The initialization and destruction of each parameter copy occurs in the
4980 : : context of the called coroutine. Initializations of parameter copies are
4981 : : sequenced before the call to the coroutine promise constructor and
4982 : : indeterminately sequenced with respect to each other. The lifetime of
4983 : : parameter copies ends immediately after the lifetime of the coroutine
4984 : : promise object ends. */
4985 : :
4986 : 1514 : if (DECL_ARGUMENTS (orig_fn_decl))
4987 : : {
4988 : 727 : promise_args = make_tree_vector ();
4989 : 1681 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
4990 : 954 : arg = DECL_CHAIN (arg))
4991 : : {
4992 : 954 : bool existed;
4993 : 954 : param_info &parm = param_uses.get_or_insert (arg, &existed);
4994 : 954 : tree fld_idx
4995 : 954 : = coro_build_frame_access_expr (deref_fp, parm.field_id,
4996 : 954 : false, tf_warning_or_error);
4997 : :
4998 : : /* Add this to the promise CTOR arguments list, accounting for
4999 : : refs and special handling for method this ptr. */
5000 : 954 : if (parm.this_ptr || parm.lambda_cobj)
5001 : : {
5002 : : /* We pass a reference to *this to the param preview. */
5003 : : /* It's unsafe to use the cp_ version here since current_class_ref
5004 : : might've gotten clobbered earlier during rewrite_param_uses. */
5005 : 239 : tree this_ref = build_fold_indirect_ref (arg);
5006 : 239 : vec_safe_push (promise_args, this_ref);
5007 : 239 : }
5008 : 715 : else if (parm.rv_ref)
5009 : 41 : vec_safe_push (promise_args, move (fld_idx));
5010 : : else
5011 : 674 : vec_safe_push (promise_args, fld_idx);
5012 : :
5013 : 954 : if (parm.rv_ref || parm.pt_ref)
5014 : : /* Initialise the frame reference field directly. */
5015 : 131 : r = build2 (INIT_EXPR, TREE_TYPE (arg),
5016 : 131 : TREE_OPERAND (fld_idx, 0), arg);
5017 : : else
5018 : : {
5019 : 823 : r = forward_parm (arg);
5020 : 823 : r = cp_build_modify_expr (loc, fld_idx, INIT_EXPR, r,
5021 : : tf_warning_or_error);
5022 : : }
5023 : 954 : finish_expr_stmt (r);
5024 : :
5025 : : /* Arrange for parm copies to be cleaned up when an exception is
5026 : : thrown before initial await resume. */
5027 : 954 : if (flag_exceptions && !parm.trivial_dtor)
5028 : : {
5029 : 77 : parm.fr_copy_dtor
5030 : 77 : = cxx_maybe_build_cleanup (fld_idx, tf_warning_or_error);
5031 : 77 : if (parm.fr_copy_dtor && parm.fr_copy_dtor != error_mark_node)
5032 : : {
5033 : 77 : param_dtor_list.safe_push (parm.field_id);
5034 : 77 : tree param_cleanup = push_stmt_list ();
5035 : 77 : tree do_cleanup
5036 : 77 : = build1_loc (loc, TRUTH_NOT_EXPR, boolean_type_node, iarc_x);
5037 : 77 : do_cleanup
5038 : 77 : = build2_loc (loc, TRUTH_ANDIF_EXPR, boolean_type_node,
5039 : : coro_before_return, do_cleanup);
5040 : 77 : r = build3_loc (loc, COND_EXPR, void_type_node, do_cleanup,
5041 : : parm.fr_copy_dtor, void_node);
5042 : 77 : finish_expr_stmt (r);
5043 : 77 : push_cleanup (fld_idx, pop_stmt_list (param_cleanup),
5044 : : /*eh_only*/true);
5045 : : }
5046 : : }
5047 : : }
5048 : : }
5049 : :
5050 : : /* Set up the promise. */
5051 : 1514 : tree p
5052 : 1514 : = coro_build_and_push_artificial_var_with_dve (loc, coro_promise_id,
5053 : : promise_type, orig_fn_decl,
5054 : : NULL_TREE, deref_fp);
5055 : :
5056 : 1514 : if (type_build_ctor_call (promise_type))
5057 : : {
5058 : : /* Construct the promise object [dcl.fct.def.coroutine] / 5.7.
5059 : :
5060 : : First try to find a constructor with an argument list comprised of
5061 : : the parameter copies. */
5062 : :
5063 : 982 : if (DECL_ARGUMENTS (orig_fn_decl))
5064 : : {
5065 : 568 : r = build_special_member_call (p, complete_ctor_identifier,
5066 : : &promise_args, promise_type,
5067 : : LOOKUP_NORMAL, tf_none);
5068 : 568 : release_tree_vector (promise_args);
5069 : : }
5070 : : else
5071 : : r = NULL_TREE;
5072 : :
5073 : : /* If that fails then the promise constructor argument list is empty. */
5074 : 568 : if (r == NULL_TREE || r == error_mark_node)
5075 : 710 : r = build_special_member_call (p, complete_ctor_identifier, NULL,
5076 : : promise_type, LOOKUP_NORMAL,
5077 : : tf_warning_or_error);
5078 : :
5079 : : /* If type_build_ctor_call() encounters deprecated implicit CTORs it will
5080 : : return true, and therefore we will execute this code path. However,
5081 : : we might well not actually require a CTOR and under those conditions
5082 : : the build call above will not return a call expression, but the
5083 : : original instance object. Do not attempt to add the statement unless
5084 : : it has side-effects. */
5085 : 982 : if (r && r != error_mark_node && TREE_SIDE_EFFECTS (r))
5086 : 972 : finish_expr_stmt (r);
5087 : : }
5088 : :
5089 : 1514 : if (flag_exceptions)
5090 : : {
5091 : 1492 : tree promise_dtor = cxx_maybe_build_cleanup (p, tf_warning_or_error);
5092 : : /* If the promise is live, then run its dtor if that's available. */
5093 : 1492 : if (promise_dtor && promise_dtor != error_mark_node)
5094 : : {
5095 : 907 : tree promise_cleanup = push_stmt_list ();
5096 : 907 : tree do_cleanup
5097 : 907 : = build1_loc (loc, TRUTH_NOT_EXPR, boolean_type_node, iarc_x);
5098 : 907 : do_cleanup = build2_loc (loc, TRUTH_ANDIF_EXPR, boolean_type_node,
5099 : : coro_before_return, do_cleanup);
5100 : 907 : r = build3 (COND_EXPR, void_type_node, do_cleanup,
5101 : : promise_dtor, void_node);
5102 : 907 : finish_expr_stmt (r);
5103 : 907 : push_cleanup (p, pop_stmt_list (promise_cleanup), /*eh_only*/true);
5104 : : }
5105 : : }
5106 : :
5107 : 1514 : tree get_ro
5108 : 1514 : = coro_build_promise_expression (orig_fn_decl, p,
5109 : : coro_get_return_object_identifier,
5110 : : fn_start, NULL, /*musthave=*/true);
5111 : :
5112 : : /* Without a return object we haven't got much clue what's going on. */
5113 : 1514 : if (!get_ro || get_ro == error_mark_node)
5114 : : return false;
5115 : :
5116 : : /* Check for a bad get return object type.
5117 : : [dcl.fct.def.coroutine] / 7 requires:
5118 : : The expression promise.get_return_object() is used to initialize the
5119 : : returned reference or prvalue result object ...
5120 : : When we use a local to hold this, it is decltype(auto). */
5121 : 1514 : tree gro_type
5122 : 1514 : = finish_decltype_type (get_ro, /*id_expression_or_member_access_p*/false,
5123 : : tf_warning_or_error);
5124 : 1514 : if (VOID_TYPE_P (gro_type) && !void_ramp_p)
5125 : : {
5126 : 3 : error_at (fn_start, "no viable conversion from %<void%> provided by"
5127 : : " %<get_return_object%> to return type %qT", fn_return_type);
5128 : 3 : return false;
5129 : : }
5130 : :
5131 : : /* Initialize the resume_idx_var to 0, meaning "not started". */
5132 : 1511 : coro_build_and_push_artificial_var_with_dve
5133 : 1511 : (loc, coro_resume_index_id, short_unsigned_type_node, orig_fn_decl,
5134 : : build_zero_cst (short_unsigned_type_node), deref_fp);
5135 : :
5136 : : /* We must manage the cleanups ourselves, with the exception of the g_r_o,
5137 : : because the responsibility for them changes after the initial suspend.
5138 : : However, any use of cxx_maybe_build_cleanup () in preceding code can
5139 : : set the throwing_cleanup flag. */
5140 : 1511 : cp_function_chain->throwing_cleanup = false;
5141 : :
5142 : : /* [dcl.fct.def.coroutine] / 7
5143 : : The expression promise.get_return_object() is used to initialize the
5144 : : glvalue result or prvalue result object of a call to a coroutine. */
5145 : :
5146 : 1511 : tree coro_gro = NULL_TREE;
5147 : 1511 : if (void_ramp_p)
5148 : : /* We still want to call the method, even if the result is unused. */
5149 : 14 : finish_expr_stmt (get_ro);
5150 : : else
5151 : : {
5152 : : /* Per CWG2563, we keep the result of promise.get_return_object () in
5153 : : a temp which is then used to intialize the return object, including
5154 : : NVRO. */
5155 : :
5156 : : /* Temporary var to hold the g_r_o across the function body. */
5157 : 1497 : coro_gro
5158 : 1497 : = coro_build_and_push_artificial_var (loc, "_Coro_gro", gro_type,
5159 : : orig_fn_decl, NULL_TREE);
5160 : :
5161 : 1497 : r = cp_build_init_expr (coro_gro, STRIP_REFERENCE_REF (get_ro));
5162 : 1497 : finish_expr_stmt (r);
5163 : 1497 : tree coro_gro_cleanup
5164 : 1497 : = cxx_maybe_build_cleanup (coro_gro, tf_warning_or_error);
5165 : 1497 : if (coro_gro_cleanup)
5166 : 216 : push_cleanup (coro_gro, coro_gro_cleanup, /*eh_only*/false);
5167 : : }
5168 : :
5169 : : /* Start the coroutine body. */
5170 : 1511 : r = build_call_expr_loc (fn_start, resumer, 1, coro_fp);
5171 : 1511 : finish_expr_stmt (r);
5172 : :
5173 : 1511 : if (flag_exceptions)
5174 : : {
5175 : 1489 : r = cp_build_modify_expr (input_location, coro_before_return, NOP_EXPR,
5176 : : boolean_false_node, tf_warning_or_error);
5177 : 1489 : finish_expr_stmt (r);
5178 : : }
5179 : :
5180 : : /* The ramp is done, we just need the return statement, which we build from
5181 : : the return object we constructed before we called the actor. */
5182 : :
5183 : 1511 : r = void_ramp_p ? NULL_TREE : convert_from_reference (coro_gro);
5184 : 1511 : finish_return_stmt (r);
5185 : :
5186 : 1511 : finish_compound_stmt (ramp_fnbody);
5187 : 1511 : return true;
5188 : 1532 : }
5189 : :
5190 : : /* ------- Encapsulate analysis of the couroutine -------- */
5191 : :
5192 : :
5193 : 1595 : cp_coroutine_transform::cp_coroutine_transform (tree _orig_fn, bool _inl)
5194 : 1595 : : orig_fn_decl (_orig_fn), inline_p (_inl)
5195 : : {
5196 : : /* We don't expect to be called with missing decl or e_m_n. */
5197 : 1595 : gcc_checking_assert (orig_fn_decl
5198 : : && TREE_CODE (orig_fn_decl) == FUNCTION_DECL);
5199 : 1595 : if (!coro_function_valid_p (orig_fn_decl))
5200 : : {
5201 : : /* For early errors, we do not want a diagnostic about the missing
5202 : : ramp return value, since the user cannot fix this - a 'return' is
5203 : : not allowed in a coroutine. */
5204 : 60 : suppress_warning (orig_fn_decl, OPT_Wreturn_type);
5205 : : /* Discard the body, we can't process it further... */
5206 : 60 : pop_stmt_list (DECL_SAVED_TREE (orig_fn_decl));
5207 : : /* ... and make an empty fn. */
5208 : 60 : DECL_SAVED_TREE (orig_fn_decl) = push_stmt_list ();
5209 : : /* Match the expected nesting when an eh block is in use. */
5210 : 60 : if (use_eh_spec_block (orig_fn_decl))
5211 : 0 : current_eh_spec_block = begin_eh_spec_block ();
5212 : 60 : valid_coroutine = false;
5213 : : }
5214 : :
5215 : : /* We don't have the locus of the opening brace - it's filled in later (and
5216 : : there doesn't really seem to be any easy way to get at it). */
5217 : 1595 : fn_start = DECL_SOURCE_LOCATION (orig_fn_decl);
5218 : : /* The closing brace is assumed to be input_location. */
5219 : 1595 : fn_end = input_location;
5220 : :
5221 : : /* Build types we need. */
5222 : 1595 : tree fr_name = get_fn_local_identifier (orig_fn_decl, "Frame");
5223 : 1595 : frame_type = xref_tag (record_type, fr_name);
5224 : 1595 : DECL_CONTEXT (TYPE_NAME (frame_type)) = DECL_CONTEXT (orig_fn_decl);
5225 : 1595 : frame_ptr_type = build_pointer_type (frame_type);
5226 : 1595 : act_des_fn_type
5227 : 1595 : = build_function_type_list (void_type_node, frame_ptr_type, NULL_TREE);
5228 : 1595 : act_des_fn_ptr_type = build_pointer_type (act_des_fn_type);
5229 : 1595 : valid_coroutine = true;
5230 : 1595 : }
5231 : :
5232 : 1595 : cp_coroutine_transform::~cp_coroutine_transform ()
5233 : : {
5234 : 1595 : }
5235 : :
5236 : : /* Here we:
5237 : : a) Check that the function and promise type are valid for a
5238 : : coroutine.
5239 : : b) Carry out the initial morph to create the skeleton of the
5240 : : coroutine ramp function and the rewritten body.
5241 : :
5242 : : Assumptions.
5243 : :
5244 : : 1. We only hit this code once all dependencies are resolved.
5245 : : 2. The function body will be either a bind expr or a statement list
5246 : : 3. That cfun and current_function_decl are valid for the case we're
5247 : : expanding.
5248 : : 4. 'input_location' will be of the final brace for the function.
5249 : :
5250 : : We do something like this:
5251 : : declare a dummy coro frame.
5252 : : struct _R_frame {
5253 : : using handle_type = coro::coroutine_handle<coro1::promise_type>;
5254 : : void (*_Coro_resume_fn)(_R_frame *);
5255 : : void (*_Coro_destroy_fn)(_R_frame *);
5256 : : coro1::promise_type _Coro_promise;
5257 : : bool _Coro_frame_needs_free; free the coro frame mem if set.
5258 : : bool _Coro_i_a_r_c; [dcl.fct.def.coroutine] / 5.3
5259 : : short _Coro_resume_index;
5260 : : handle_type _Coro_self_handle;
5261 : : parameter copies (were required).
5262 : : local variables saved (including awaitables)
5263 : : (maybe) trailing space.
5264 : : }; */
5265 : :
5266 : : void
5267 : 1595 : cp_coroutine_transform::apply_transforms ()
5268 : : {
5269 : 1595 : if (dmp_str == NULL)
5270 : 1595 : dmp_str = dump_begin (coro_dump_id, &coro_dump_flags);
5271 : :
5272 : 1595 : coro_maybe_dump_initial_function (orig_fn_decl);
5273 : :
5274 : 1595 : coroutine_body
5275 : 1595 : = split_coroutine_body_from_ramp (orig_fn_decl);
5276 : 1595 : if (!coroutine_body)
5277 : : {
5278 : 63 : valid_coroutine = false;
5279 : 63 : return;
5280 : : }
5281 : : /* Keep the original function block tree to one side and reset. */
5282 : 1532 : body_blocks = current_binding_level->blocks;
5283 : 1532 : current_binding_level->blocks = NULL_TREE;
5284 : :
5285 : : /* Collect information on the original function params and their use in the
5286 : : function body. */
5287 : 1532 : analyze_fn_parms ();
5288 : :
5289 : : /* Declare the actor and destroyer functions, the following code needs to
5290 : : see these. */
5291 : 1532 : resumer
5292 : 1532 : = coro_build_actor_or_destroy_function (orig_fn_decl, act_des_fn_type,
5293 : : frame_ptr_type, true);
5294 : 1532 : destroyer
5295 : 1532 : = coro_build_actor_or_destroy_function (orig_fn_decl, act_des_fn_type,
5296 : : frame_ptr_type, false);
5297 : :
5298 : : /* Avoid repeating diagnostics about promise or awaiter fails. */
5299 : 1532 : if (!seen_error ())
5300 : : {
5301 : 1505 : iloc_sentinel stable_input_loc (fn_start);
5302 : 1505 : initial_await = build_init_or_final_await (fn_start, false);
5303 : 1505 : input_location = fn_end;
5304 : 1505 : if (initial_await && initial_await != error_mark_node)
5305 : 1499 : final_await = build_init_or_final_await (fn_end, true);
5306 : 1505 : }
5307 : :
5308 : : /* Transform the function body as per [dcl.fct.def.coroutine] / 5. */
5309 : 1532 : wrap_original_function_body ();
5310 : :
5311 : : /* Analyze the body await expressions. */
5312 : 1532 : susp_frame_data body_aw_points (fs_label, &suspend_points);
5313 : 1532 : cp_walk_tree (&coroutine_body, await_statement_walker, &body_aw_points, NULL);
5314 : 1532 : await_count = body_aw_points.await_number;
5315 : :
5316 : : /* Determine the fields for the coroutine state. */
5317 : 1532 : tree field_list = NULL_TREE;
5318 : 1532 : local_vars_frame_data local_vars_data (&field_list, &local_var_uses);
5319 : 1532 : cp_walk_tree_without_duplicates (&coroutine_body, register_local_var_uses,
5320 : : &local_vars_data);
5321 : :
5322 : : /* Conservative computation of the coroutine frame content. */
5323 : 1532 : frame_type = begin_class_definition (frame_type);
5324 : 1532 : TYPE_FIELDS (frame_type) = field_list;
5325 : 1532 : TYPE_BINFO (frame_type) = make_tree_binfo (0);
5326 : 1532 : BINFO_OFFSET (TYPE_BINFO (frame_type)) = size_zero_node;
5327 : 1532 : BINFO_TYPE (TYPE_BINFO (frame_type)) = frame_type;
5328 : 1532 : frame_type = finish_struct (frame_type, NULL_TREE);
5329 : :
5330 : 1532 : valid_coroutine = build_ramp_function ();
5331 : 1532 : coro_maybe_dump_ramp (orig_fn_decl);
5332 : : }
5333 : :
5334 : : /* Having analysed and collected the necessary data we are now in a position
5335 : : to build the outlined coroutine body and the destroyer shim. */
5336 : :
5337 : : void
5338 : 1511 : cp_coroutine_transform::finish_transforms ()
5339 : : {
5340 : 1511 : if (!valid_coroutine)
5341 : : return;
5342 : :
5343 : 1511 : current_function_decl = resumer;
5344 : 1511 : build_actor_fn (fn_start, frame_type, resumer, coroutine_body, orig_fn_decl,
5345 : : &local_var_uses, &suspend_points, ¶m_dtor_list,
5346 : 1511 : resume_idx_var, await_count, frame_size, inline_p);
5347 : :
5348 : 1511 : current_function_decl = destroyer;
5349 : 1511 : build_destroy_fn (fn_start, frame_type, destroyer, resumer, inline_p);
5350 : :
5351 : 1511 : coro_maybe_dump_transformed_functions (resumer, destroyer);
5352 : : }
5353 : :
5354 : : #include "gt-cp-coroutines.h"
5355 : :
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