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1 : : /* coroutine-specific state, expansions and tests.
2 : :
3 : : Copyright (C) 2018-2024 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 : : static bool coro_promise_type_found_p (tree, location_t);
38 : :
39 : : /* GCC C++ coroutines implementation.
40 : :
41 : : The user authors a function that becomes a coroutine (lazily) by
42 : : making use of any of the co_await, co_yield or co_return keywords.
43 : :
44 : : Unlike a regular function, where the activation record is placed on the
45 : : stack, and is destroyed on function exit, a coroutine has some state that
46 : : persists between calls - the coroutine frame (analogous to a stack frame).
47 : :
48 : : We transform the user's function into three pieces:
49 : : 1. A so-called ramp function, that establishes the coroutine frame and
50 : : begins execution of the coroutine.
51 : : 2. An actor function that contains the state machine corresponding to the
52 : : user's suspend/resume structure.
53 : : 3. A stub function that calls the actor function in 'destroy' mode.
54 : :
55 : : The actor function is executed:
56 : : * from "resume point 0" by the ramp.
57 : : * from resume point N ( > 0 ) for handle.resume() calls.
58 : : * from the destroy stub for destroy point N for handle.destroy() calls.
59 : :
60 : : The functions in this file carry out the necessary analysis of, and
61 : : transforms to, the AST to perform this.
62 : :
63 : : The C++ coroutine design makes use of some helper functions that are
64 : : authored in a so-called "promise" class provided by the user.
65 : :
66 : : At parse time (or post substitution) the type of the coroutine promise
67 : : will be determined. At that point, we can look up the required promise
68 : : class methods and issue diagnostics if they are missing or incorrect. To
69 : : avoid repeating these actions at code-gen time, we make use of temporary
70 : : 'proxy' variables for the coroutine handle and the promise - which will
71 : : eventually be instantiated in the coroutine frame.
72 : :
73 : : Each of the keywords will expand to a code sequence (although co_yield is
74 : : just syntactic sugar for a co_await).
75 : :
76 : : We defer the analysis and transformation until template expansion is
77 : : complete so that we have complete types at that time. */
78 : :
79 : :
80 : : /* The state that we collect during parsing (and template expansion) for
81 : : a coroutine. */
82 : :
83 : 2571 : struct GTY((for_user)) coroutine_info
84 : : {
85 : : tree function_decl; /* The original function decl. */
86 : : tree actor_decl; /* The synthesized actor function. */
87 : : tree destroy_decl; /* The synthesized destroy function. */
88 : : tree promise_type; /* The cached promise type for this function. */
89 : : tree traits_type; /* The cached traits type for this function. */
90 : : tree handle_type; /* The cached coroutine handle for this function. */
91 : : tree self_h_proxy; /* A handle instance that is used as the proxy for the
92 : : one that will eventually be allocated in the coroutine
93 : : frame. */
94 : : tree promise_proxy; /* Likewise, a proxy promise instance. */
95 : : tree from_address; /* handle_type from_address function. */
96 : : tree return_void; /* The expression for p.return_void() if it exists. */
97 : : location_t first_coro_keyword; /* The location of the keyword that made this
98 : : function into a coroutine. */
99 : :
100 : : /* Temporary variable number assigned by get_awaitable_var. */
101 : : int awaitable_number = 0;
102 : :
103 : : /* Flags to avoid repeated errors for per-function issues. */
104 : : bool coro_ret_type_error_emitted;
105 : : bool coro_promise_error_emitted;
106 : : bool coro_co_return_error_emitted;
107 : : };
108 : :
109 : : struct coroutine_info_hasher : ggc_ptr_hash<coroutine_info>
110 : : {
111 : : typedef tree compare_type; /* We only compare the function decl. */
112 : : static inline hashval_t hash (coroutine_info *);
113 : : static inline hashval_t hash (const compare_type &);
114 : : static inline bool equal (coroutine_info *, coroutine_info *);
115 : : static inline bool equal (coroutine_info *, const compare_type &);
116 : : };
117 : :
118 : : /* This table holds all the collected coroutine state for coroutines in
119 : : the current translation unit. */
120 : :
121 : : static GTY (()) hash_table<coroutine_info_hasher> *coroutine_info_table;
122 : :
123 : : /* We will initialize state lazily. */
124 : : static bool coro_initialized = false;
125 : :
126 : : /* Return a hash value for the entry pointed to by INFO.
127 : : The compare type is a tree, but the only trees we are going use are
128 : : function decls. We use the DECL_UID as the hash value since that is
129 : : stable across PCH. */
130 : :
131 : : hashval_t
132 : 57372 : coroutine_info_hasher::hash (coroutine_info *info)
133 : : {
134 : 57372 : return DECL_UID (info->function_decl);
135 : : }
136 : :
137 : : /* Return a hash value for the compare value COMP. */
138 : :
139 : : hashval_t
140 : 52699 : coroutine_info_hasher::hash (const compare_type& comp)
141 : : {
142 : 52699 : return DECL_UID (comp);
143 : : }
144 : :
145 : : /* Return true if the entries pointed to by LHS and RHS are for the
146 : : same coroutine. */
147 : :
148 : : bool
149 : : coroutine_info_hasher::equal (coroutine_info *lhs, coroutine_info *rhs)
150 : : {
151 : : return lhs->function_decl == rhs->function_decl;
152 : : }
153 : :
154 : : bool
155 : 67644 : coroutine_info_hasher::equal (coroutine_info *lhs, const compare_type& rhs)
156 : : {
157 : 67644 : return lhs->function_decl == rhs;
158 : : }
159 : :
160 : : /* Get the existing coroutine_info for FN_DECL, or insert a new one if the
161 : : entry does not yet exist. */
162 : :
163 : : coroutine_info *
164 : 8731 : get_or_insert_coroutine_info (tree fn_decl)
165 : : {
166 : 8731 : gcc_checking_assert (coroutine_info_table != NULL);
167 : :
168 : 8731 : coroutine_info **slot = coroutine_info_table->find_slot_with_hash
169 : 8731 : (fn_decl, coroutine_info_hasher::hash (fn_decl), INSERT);
170 : :
171 : 8731 : if (*slot == NULL)
172 : : {
173 : 2571 : *slot = new (ggc_cleared_alloc<coroutine_info> ()) coroutine_info ();
174 : 2571 : (*slot)->function_decl = fn_decl;
175 : : }
176 : :
177 : 8731 : return *slot;
178 : : }
179 : :
180 : : /* Get the existing coroutine_info for FN_DECL, fail if it doesn't exist. */
181 : :
182 : : coroutine_info *
183 : 43968 : get_coroutine_info (tree fn_decl)
184 : : {
185 : 43968 : if (coroutine_info_table == NULL)
186 : : return NULL;
187 : :
188 : 43968 : coroutine_info **slot = coroutine_info_table->find_slot_with_hash
189 : 43968 : (fn_decl, coroutine_info_hasher::hash (fn_decl), NO_INSERT);
190 : 43968 : if (slot)
191 : 43968 : return *slot;
192 : : return NULL;
193 : : }
194 : :
195 : : /* We will lazily create all the identifiers that are used by coroutines
196 : : on the first attempt to lookup the traits. */
197 : :
198 : : /* Identifiers that are used by all coroutines. */
199 : :
200 : : static GTY(()) tree coro_traits_identifier;
201 : : static GTY(()) tree coro_handle_identifier;
202 : : static GTY(()) tree coro_promise_type_identifier;
203 : :
204 : : /* Required promise method name identifiers. */
205 : :
206 : : static GTY(()) tree coro_await_transform_identifier;
207 : : static GTY(()) tree coro_initial_suspend_identifier;
208 : : static GTY(()) tree coro_final_suspend_identifier;
209 : : static GTY(()) tree coro_return_void_identifier;
210 : : static GTY(()) tree coro_return_value_identifier;
211 : : static GTY(()) tree coro_yield_value_identifier;
212 : : static GTY(()) tree coro_address_identifier;
213 : : static GTY(()) tree coro_from_address_identifier;
214 : : static GTY(()) tree coro_get_return_object_identifier;
215 : : static GTY(()) tree coro_gro_on_allocation_fail_identifier;
216 : : static GTY(()) tree coro_unhandled_exception_identifier;
217 : :
218 : : /* Awaitable methods. */
219 : :
220 : : static GTY(()) tree coro_await_ready_identifier;
221 : : static GTY(()) tree coro_await_suspend_identifier;
222 : : static GTY(()) tree coro_await_resume_identifier;
223 : :
224 : : /* Accessors for the coroutine frame state used by the implementation. */
225 : :
226 : : static GTY(()) tree coro_resume_fn_id;
227 : : static GTY(()) tree coro_destroy_fn_id;
228 : : static GTY(()) tree coro_promise_id;
229 : : static GTY(()) tree coro_frame_needs_free_id;
230 : : static GTY(()) tree coro_resume_index_id;
231 : : static GTY(()) tree coro_self_handle_id;
232 : : static GTY(()) tree coro_actor_continue_id;
233 : : static GTY(()) tree coro_frame_i_a_r_c_id;
234 : :
235 : : /* Create the identifiers used by the coroutines library interfaces and
236 : : the implementation frame state. */
237 : :
238 : : static void
239 : 2248 : coro_init_identifiers ()
240 : : {
241 : 2248 : coro_traits_identifier = get_identifier ("coroutine_traits");
242 : 2248 : coro_handle_identifier = get_identifier ("coroutine_handle");
243 : 2248 : coro_promise_type_identifier = get_identifier ("promise_type");
244 : :
245 : 2248 : coro_await_transform_identifier = get_identifier ("await_transform");
246 : 2248 : coro_initial_suspend_identifier = get_identifier ("initial_suspend");
247 : 2248 : coro_final_suspend_identifier = get_identifier ("final_suspend");
248 : 2248 : coro_return_void_identifier = get_identifier ("return_void");
249 : 2248 : coro_return_value_identifier = get_identifier ("return_value");
250 : 2248 : coro_yield_value_identifier = get_identifier ("yield_value");
251 : 2248 : coro_address_identifier = get_identifier ("address");
252 : 2248 : coro_from_address_identifier = get_identifier ("from_address");
253 : 2248 : coro_get_return_object_identifier = get_identifier ("get_return_object");
254 : 4496 : coro_gro_on_allocation_fail_identifier =
255 : 2248 : get_identifier ("get_return_object_on_allocation_failure");
256 : 2248 : coro_unhandled_exception_identifier = get_identifier ("unhandled_exception");
257 : :
258 : 2248 : coro_await_ready_identifier = get_identifier ("await_ready");
259 : 2248 : coro_await_suspend_identifier = get_identifier ("await_suspend");
260 : 2248 : coro_await_resume_identifier = get_identifier ("await_resume");
261 : :
262 : : /* Coroutine state frame field accessors. */
263 : 2248 : coro_resume_fn_id = get_identifier ("_Coro_resume_fn");
264 : 2248 : coro_destroy_fn_id = get_identifier ("_Coro_destroy_fn");
265 : 2248 : coro_promise_id = get_identifier ("_Coro_promise");
266 : 2248 : coro_frame_needs_free_id = get_identifier ("_Coro_frame_needs_free");
267 : 2248 : coro_frame_i_a_r_c_id = get_identifier ("_Coro_initial_await_resume_called");
268 : 2248 : coro_resume_index_id = get_identifier ("_Coro_resume_index");
269 : 2248 : coro_self_handle_id = get_identifier ("_Coro_self_handle");
270 : 2248 : coro_actor_continue_id = get_identifier ("_Coro_actor_continue");
271 : 2248 : }
272 : :
273 : : /* Trees we only need to set up once. */
274 : :
275 : : static GTY(()) tree coro_traits_templ;
276 : : static GTY(()) tree coro_handle_templ;
277 : : static GTY(()) tree void_coro_handle_type;
278 : : static GTY(()) tree void_coro_handle_address;
279 : :
280 : : /* ================= Parse, Semantics and Type checking ================= */
281 : :
282 : : /* This initial set of routines are helper for the parsing and template
283 : : expansion phases.
284 : :
285 : : At the completion of this, we will have completed trees for each of the
286 : : keywords, but making use of proxy variables for the self-handle and the
287 : : promise class instance. */
288 : :
289 : : /* [coroutine.traits]
290 : : Lookup the coroutine_traits template decl. */
291 : :
292 : : static tree
293 : 2248 : find_coro_traits_template_decl (location_t kw)
294 : : {
295 : : /* If we are missing fundamental information, such as the traits, (or the
296 : : declaration found is not a type template), then don't emit an error for
297 : : every keyword in a TU, just do it once. */
298 : 2248 : static bool traits_error_emitted = false;
299 : :
300 : 4496 : tree traits_decl = lookup_qualified_name (std_node, coro_traits_identifier,
301 : : LOOK_want::NORMAL,
302 : 2248 : /*complain=*/!traits_error_emitted);
303 : 2248 : if (traits_decl == error_mark_node
304 : 2248 : || !DECL_TYPE_TEMPLATE_P (traits_decl))
305 : : {
306 : 10 : if (!traits_error_emitted)
307 : : {
308 : 4 : auto_diagnostic_group d;
309 : 4 : gcc_rich_location richloc (kw);
310 : 4 : error_at (&richloc, "coroutines require a traits template; cannot"
311 : : " find %<%E::%E%>", std_node, coro_traits_identifier);
312 : 4 : inform (&richloc, "perhaps %<#include <coroutine>%> is missing");
313 : 4 : traits_error_emitted = true;
314 : 4 : }
315 : 10 : return NULL_TREE;
316 : : }
317 : : else
318 : : return traits_decl;
319 : : }
320 : :
321 : : /* Instantiate Coroutine traits for the function signature. */
322 : :
323 : : static tree
324 : 2571 : instantiate_coro_traits (tree fndecl, location_t kw)
325 : : {
326 : : /* [coroutine.traits.primary]
327 : : So now build up a type list for the template <typename _R, typename...>.
328 : : The types are the function's arg types and _R is the function return
329 : : type. */
330 : :
331 : 2571 : tree functyp = TREE_TYPE (fndecl);
332 : 2571 : tree arg = DECL_ARGUMENTS (fndecl);
333 : 2571 : tree arg_node = TYPE_ARG_TYPES (functyp);
334 : 2571 : tree argtypes = make_tree_vec (list_length (arg_node)-1);
335 : 2571 : unsigned p = 0;
336 : :
337 : 20599 : while (arg_node != NULL_TREE && !VOID_TYPE_P (TREE_VALUE (arg_node)))
338 : : {
339 : 6443 : if (is_this_parameter (arg)
340 : 6443 : || DECL_NAME (arg) == closure_identifier)
341 : : {
342 : : /* We pass a reference to *this to the param preview. */
343 : 1349 : tree ct = TREE_TYPE (TREE_TYPE (arg));
344 : 1349 : TREE_VEC_ELT (argtypes, p++) = cp_build_reference_type (ct, false);
345 : : }
346 : : else
347 : 5094 : TREE_VEC_ELT (argtypes, p++) = TREE_VALUE (arg_node);
348 : :
349 : 6443 : arg_node = TREE_CHAIN (arg_node);
350 : 6443 : arg = DECL_CHAIN (arg);
351 : : }
352 : :
353 : 2571 : tree argtypepack = cxx_make_type (TYPE_ARGUMENT_PACK);
354 : 2571 : ARGUMENT_PACK_ARGS (argtypepack) = argtypes;
355 : :
356 : 2571 : tree targ = make_tree_vec (2);
357 : 2571 : TREE_VEC_ELT (targ, 0) = TREE_TYPE (functyp);
358 : 2571 : TREE_VEC_ELT (targ, 1) = argtypepack;
359 : :
360 : 2571 : tree traits_class
361 : 2571 : = lookup_template_class (coro_traits_templ, targ,
362 : : /*in_decl=*/NULL_TREE, /*context=*/NULL_TREE,
363 : : tf_warning_or_error);
364 : :
365 : 2571 : if (traits_class == error_mark_node)
366 : : {
367 : 0 : error_at (kw, "cannot instantiate %<coroutine traits%>");
368 : 0 : return NULL_TREE;
369 : : }
370 : :
371 : : return traits_class;
372 : : }
373 : :
374 : : /* [coroutine.handle] */
375 : :
376 : : static tree
377 : 2238 : find_coro_handle_template_decl (location_t kw)
378 : : {
379 : : /* As for the coroutine traits, this error is per TU, so only emit
380 : : it once. */
381 : 2238 : static bool coro_handle_error_emitted = false;
382 : 4476 : tree handle_decl = lookup_qualified_name (std_node, coro_handle_identifier,
383 : : LOOK_want::NORMAL,
384 : 2238 : !coro_handle_error_emitted);
385 : 2238 : if (handle_decl == error_mark_node
386 : 2238 : || !DECL_CLASS_TEMPLATE_P (handle_decl))
387 : : {
388 : 6 : if (!coro_handle_error_emitted)
389 : 2 : error_at (kw, "coroutines require a handle class template;"
390 : : " cannot find %<%E::%E%>", std_node, coro_handle_identifier);
391 : 6 : coro_handle_error_emitted = true;
392 : 6 : return NULL_TREE;
393 : : }
394 : : else
395 : : return handle_decl;
396 : : }
397 : :
398 : : /* Get and validate HANDLE_TYPE::address. The resulting function, if any, will
399 : : be a non-overloaded member function that takes no arguments and returns
400 : : void*. If that is not the case, signals an error and returns NULL_TREE. */
401 : :
402 : : static tree
403 : 2232 : get_handle_type_address (location_t kw, tree handle_type)
404 : : {
405 : 2232 : tree addr_getter = lookup_member (handle_type, coro_address_identifier, 1,
406 : : 0, tf_warning_or_error);
407 : 2232 : if (!addr_getter || addr_getter == error_mark_node)
408 : : {
409 : 6 : qualified_name_lookup_error (handle_type, coro_address_identifier,
410 : : error_mark_node, kw);
411 : 6 : return NULL_TREE;
412 : : }
413 : :
414 : 2226 : if (!BASELINK_P (addr_getter)
415 : 2226 : || TREE_CODE (TREE_TYPE (addr_getter)) != METHOD_TYPE)
416 : : {
417 : 6 : error_at (kw, "%qE must be a non-overloaded method", addr_getter);
418 : 6 : return NULL_TREE;
419 : : }
420 : :
421 : 2220 : tree fn_t = TREE_TYPE (addr_getter);
422 : 2220 : tree arg = TYPE_ARG_TYPES (fn_t);
423 : :
424 : : /* Skip the 'this' pointer. */
425 : 2220 : arg = TREE_CHAIN (arg);
426 : :
427 : : /* Check that from_addr has the argument list (). */
428 : 2220 : if (arg != void_list_node)
429 : : {
430 : 0 : error_at (kw, "%qE must take no arguments", addr_getter);
431 : 0 : return NULL_TREE;
432 : : }
433 : :
434 : 2220 : tree ret_t = TREE_TYPE (fn_t);
435 : 2220 : if (!same_type_p (ret_t, ptr_type_node))
436 : : {
437 : 0 : error_at (kw, "%qE must return %qT, not %qT",
438 : : addr_getter, ptr_type_node, ret_t);
439 : 0 : return NULL_TREE;
440 : : }
441 : :
442 : : return addr_getter;
443 : : }
444 : :
445 : : /* Get and validate HANDLE_TYPE::from_address. The resulting function, if
446 : : any, will be a non-overloaded static function that takes a single void* and
447 : : returns HANDLE_TYPE. If that is not the case, signals an error and returns
448 : : NULL_TREE. */
449 : :
450 : : static tree
451 : 1323 : get_handle_type_from_address (location_t kw, tree handle_type)
452 : : {
453 : 1323 : tree from_addr = lookup_member (handle_type, coro_from_address_identifier, 1,
454 : : 0, tf_warning_or_error);
455 : 1323 : if (!from_addr || from_addr == error_mark_node)
456 : : {
457 : 2 : qualified_name_lookup_error (handle_type, coro_from_address_identifier,
458 : : error_mark_node, kw);
459 : 2 : return NULL_TREE;
460 : : }
461 : 1321 : if (!BASELINK_P (from_addr)
462 : 1321 : || TREE_CODE (TREE_TYPE (from_addr)) != FUNCTION_TYPE)
463 : : {
464 : 1 : error_at (kw, "%qE must be a non-overloaded static function", from_addr);
465 : 1 : return NULL_TREE;
466 : : }
467 : :
468 : 1320 : tree fn_t = TREE_TYPE (from_addr);
469 : 1320 : tree arg = TYPE_ARG_TYPES (fn_t);
470 : : /* Check that from_addr has the argument list (void*). */
471 : 1320 : if (!arg
472 : 1320 : || !same_type_p (TREE_VALUE (arg), ptr_type_node)
473 : 2640 : || TREE_CHAIN (arg) != void_list_node)
474 : : {
475 : 0 : error_at (kw, "%qE must take a single %qT", from_addr, ptr_type_node);
476 : 0 : return NULL_TREE;
477 : : }
478 : :
479 : 1320 : tree ret_t = TREE_TYPE (fn_t);
480 : 1320 : if (!same_type_p (ret_t, handle_type))
481 : : {
482 : 0 : error_at (kw, "%qE must return %qT, not %qT",
483 : : from_addr, handle_type, ret_t);
484 : 0 : return NULL_TREE;
485 : : }
486 : :
487 : : return from_addr;
488 : : }
489 : :
490 : : static tree
491 : 3555 : instantiate_coro_handle_for_promise_type (location_t kw, tree promise_type)
492 : : {
493 : : /* So now build up a type list for the template, one entry, the promise. */
494 : 3555 : tree targ = make_tree_vec (1);
495 : 3555 : TREE_VEC_ELT (targ, 0) = promise_type;
496 : 3555 : tree handle_type
497 : 3555 : = lookup_template_class (coro_handle_identifier, targ,
498 : : /* in_decl=*/NULL_TREE,
499 : : /* context=*/std_node,
500 : : tf_warning_or_error);
501 : :
502 : 3555 : if (handle_type == error_mark_node)
503 : : {
504 : 0 : error_at (kw, "cannot instantiate a %<coroutine handle%> for"
505 : : " promise type %qT", promise_type);
506 : 0 : return NULL_TREE;
507 : : }
508 : :
509 : : return handle_type;
510 : : }
511 : :
512 : : /* Look for the promise_type in the instantiated traits. */
513 : :
514 : : static tree
515 : 1331 : find_promise_type (tree traits_class)
516 : : {
517 : 1331 : tree promise_type
518 : 1331 : = lookup_member (traits_class, coro_promise_type_identifier,
519 : : /* protect=*/1, /*want_type=*/true, tf_warning_or_error);
520 : :
521 : 1331 : if (promise_type)
522 : 1325 : promise_type
523 : 1325 : = complete_type_or_else (TREE_TYPE (promise_type), promise_type);
524 : :
525 : : /* NULL_TREE on fail. */
526 : 1331 : return promise_type;
527 : : }
528 : :
529 : : /* Perform initialization of the coroutine processor state, if not done
530 : : before. */
531 : :
532 : : static bool
533 : 7428 : ensure_coro_initialized (location_t loc)
534 : : {
535 : 7428 : if (!coro_initialized)
536 : : {
537 : : /* Trees we only need to create once.
538 : : Set up the identifiers we will use. */
539 : 2248 : coro_init_identifiers ();
540 : :
541 : : /* Coroutine traits template. */
542 : 2248 : coro_traits_templ = find_coro_traits_template_decl (loc);
543 : 2248 : if (coro_traits_templ == NULL_TREE)
544 : : return false;
545 : :
546 : : /* coroutine_handle<> template. */
547 : 2238 : coro_handle_templ = find_coro_handle_template_decl (loc);
548 : 2238 : if (coro_handle_templ == NULL_TREE)
549 : : return false;
550 : :
551 : : /* We can also instantiate the void coroutine_handle<> */
552 : 2232 : void_coro_handle_type
553 : 2232 : = instantiate_coro_handle_for_promise_type (loc, void_type_node);
554 : 2232 : if (void_coro_handle_type == NULL_TREE)
555 : : return false;
556 : :
557 : 2232 : void_coro_handle_address
558 : 2232 : = get_handle_type_address (loc, void_coro_handle_type);
559 : 2232 : if (!void_coro_handle_address)
560 : : return false;
561 : :
562 : : /* A table to hold the state, per coroutine decl. */
563 : 2220 : gcc_checking_assert (coroutine_info_table == NULL);
564 : 4440 : coroutine_info_table =
565 : 2220 : hash_table<coroutine_info_hasher>::create_ggc (11);
566 : :
567 : 2220 : if (coroutine_info_table == NULL)
568 : : return false;
569 : :
570 : 2220 : coro_initialized = true;
571 : : }
572 : : return true;
573 : : }
574 : :
575 : : /* Try to get the coroutine traits class. */
576 : : static tree
577 : 5065 : coro_get_traits_class (tree fndecl, location_t loc)
578 : : {
579 : 5065 : gcc_assert (fndecl != NULL_TREE);
580 : 5065 : gcc_assert (coro_initialized);
581 : :
582 : 5065 : coroutine_info *coro_info = get_or_insert_coroutine_info (fndecl);
583 : 5065 : auto& traits_type = coro_info->traits_type;
584 : 5065 : if (!traits_type)
585 : 2571 : traits_type = instantiate_coro_traits (fndecl, loc);
586 : 5065 : return traits_type;
587 : : }
588 : :
589 : : static bool
590 : 3678 : coro_promise_type_found_p (tree fndecl, location_t loc)
591 : : {
592 : 3678 : gcc_assert (fndecl != NULL_TREE);
593 : :
594 : 3678 : if (!ensure_coro_initialized (loc))
595 : : return false;
596 : :
597 : : /* Save the coroutine data on the side to avoid the overhead on every
598 : : function decl tree. */
599 : :
600 : 3666 : coroutine_info *coro_info = get_or_insert_coroutine_info (fndecl);
601 : : /* Without this, we cannot really proceed. */
602 : 3666 : gcc_checking_assert (coro_info);
603 : :
604 : : /* If we don't already have a current promise type, try to look it up. */
605 : 3666 : if (coro_info->promise_type == NULL_TREE)
606 : : {
607 : : /* Get the coroutine traits template class instance for the function
608 : : signature we have - coroutine_traits <R, ...> */
609 : :
610 : 1331 : tree templ_class = coro_get_traits_class (fndecl, loc);
611 : :
612 : : /* Find the promise type for that. */
613 : 1331 : coro_info->promise_type = find_promise_type (templ_class);
614 : :
615 : : /* If we don't find it, punt on the rest. */
616 : 1331 : if (coro_info->promise_type == NULL_TREE)
617 : : {
618 : 6 : if (!coro_info->coro_promise_error_emitted)
619 : 2 : error_at (loc, "unable to find the promise type for"
620 : : " this coroutine");
621 : 6 : coro_info->coro_promise_error_emitted = true;
622 : 6 : return false;
623 : : }
624 : :
625 : : /* Test for errors in the promise type that can be determined now. */
626 : 1325 : tree has_ret_void = lookup_member (coro_info->promise_type,
627 : : coro_return_void_identifier,
628 : : /*protect=*/1, /*want_type=*/0,
629 : : tf_none);
630 : 1325 : tree has_ret_val = lookup_member (coro_info->promise_type,
631 : : coro_return_value_identifier,
632 : : /*protect=*/1, /*want_type=*/0,
633 : : tf_none);
634 : 1325 : if (has_ret_void && has_ret_val)
635 : : {
636 : 2 : auto_diagnostic_group d;
637 : 2 : location_t ploc = DECL_SOURCE_LOCATION (fndecl);
638 : 2 : if (!coro_info->coro_co_return_error_emitted)
639 : 2 : error_at (ploc, "the coroutine promise type %qT declares both"
640 : : " %<return_value%> and %<return_void%>",
641 : : coro_info->promise_type);
642 : 2 : inform (DECL_SOURCE_LOCATION (BASELINK_FUNCTIONS (has_ret_void)),
643 : : "%<return_void%> declared here");
644 : 2 : has_ret_val = BASELINK_FUNCTIONS (has_ret_val);
645 : 2 : const char *message = "%<return_value%> declared here";
646 : 2 : if (TREE_CODE (has_ret_val) == OVERLOAD)
647 : : {
648 : 2 : has_ret_val = OVL_FIRST (has_ret_val);
649 : : message = "%<return_value%> first declared here";
650 : : }
651 : 2 : inform (DECL_SOURCE_LOCATION (has_ret_val), message);
652 : 2 : coro_info->coro_co_return_error_emitted = true;
653 : 2 : return false;
654 : 2 : }
655 : :
656 : : /* Try to find the handle type for the promise. */
657 : 1323 : tree handle_type
658 : 1323 : = instantiate_coro_handle_for_promise_type (loc, coro_info->promise_type);
659 : 1323 : if (handle_type == NULL_TREE)
660 : : return false;
661 : 1323 : tree from_address = get_handle_type_from_address (loc, handle_type);
662 : 1323 : if (from_address == NULL_TREE)
663 : : return false;
664 : :
665 : : /* Complete this, we're going to use it. */
666 : 1320 : coro_info->handle_type = complete_type_or_else (handle_type, fndecl);
667 : 1320 : coro_info->from_address = from_address;
668 : :
669 : : /* Diagnostic would be emitted by complete_type_or_else. */
670 : 1320 : if (!coro_info->handle_type)
671 : : return false;
672 : :
673 : : /* Build a proxy for a handle to "self" as the param to
674 : : await_suspend() calls. */
675 : 1320 : coro_info->self_h_proxy
676 : 1320 : = build_lang_decl (VAR_DECL, coro_self_handle_id,
677 : : coro_info->handle_type);
678 : :
679 : : /* Build a proxy for the promise so that we can perform lookups. */
680 : 1320 : coro_info->promise_proxy
681 : 1320 : = build_lang_decl (VAR_DECL, coro_promise_id,
682 : : coro_info->promise_type);
683 : :
684 : : /* Note where we first saw a coroutine keyword. */
685 : 1320 : coro_info->first_coro_keyword = loc;
686 : : }
687 : :
688 : : return true;
689 : : }
690 : :
691 : : /* Map from actor or destroyer to ramp. */
692 : : static GTY(()) hash_map<tree, tree> *to_ramp;
693 : :
694 : : /* Given a tree that is an actor or destroy, find the ramp function. */
695 : :
696 : : tree
697 : 135143307 : coro_get_ramp_function (tree decl)
698 : : {
699 : 135143307 : if (!to_ramp)
700 : : return NULL_TREE;
701 : 430259 : tree *p = to_ramp->get (decl);
702 : 430259 : if (p)
703 : 2889 : return *p;
704 : : return NULL_TREE;
705 : : }
706 : :
707 : : /* Given the DECL for a ramp function (the user's original declaration) return
708 : : the actor function if it has been defined. */
709 : :
710 : : tree
711 : 2544 : coro_get_actor_function (tree decl)
712 : : {
713 : 2544 : if (coroutine_info *info = get_coroutine_info (decl))
714 : 2544 : return info->actor_decl;
715 : :
716 : : return NULL_TREE;
717 : : }
718 : :
719 : : /* Given the DECL for a ramp function (the user's original declaration) return
720 : : the destroy function if it has been defined. */
721 : :
722 : : tree
723 : 1272 : coro_get_destroy_function (tree decl)
724 : : {
725 : 1272 : if (coroutine_info *info = get_coroutine_info (decl))
726 : 1272 : return info->destroy_decl;
727 : :
728 : : return NULL_TREE;
729 : : }
730 : :
731 : : /* Given a CO_AWAIT_EXPR AWAIT_EXPR, return its resume call. */
732 : :
733 : : tree*
734 : 50 : co_await_get_resume_call (tree await_expr)
735 : : {
736 : 50 : gcc_checking_assert (TREE_CODE (await_expr) == CO_AWAIT_EXPR);
737 : 50 : tree vec = TREE_OPERAND (await_expr, 3);
738 : 50 : if (!vec)
739 : : return nullptr;
740 : 50 : return &TREE_VEC_ELT (vec, 2);
741 : : }
742 : :
743 : :
744 : : /* These functions assumes that the caller has verified that the state for
745 : : the decl has been initialized, we try to minimize work here. */
746 : :
747 : : static tree
748 : 17775 : get_coroutine_promise_type (tree decl)
749 : : {
750 : 17775 : if (coroutine_info *info = get_coroutine_info (decl))
751 : 16471 : return info->promise_type;
752 : :
753 : : return NULL_TREE;
754 : : }
755 : :
756 : : static tree
757 : 1309 : get_coroutine_handle_type (tree decl)
758 : : {
759 : 1309 : if (coroutine_info *info = get_coroutine_info (decl))
760 : 0 : return info->handle_type;
761 : :
762 : : return NULL_TREE;
763 : : }
764 : :
765 : : static tree
766 : 4856 : get_coroutine_self_handle_proxy (tree decl)
767 : : {
768 : 4856 : if (coroutine_info *info = get_coroutine_info (decl))
769 : 4856 : return info->self_h_proxy;
770 : :
771 : : return NULL_TREE;
772 : : }
773 : :
774 : : static tree
775 : 7215 : get_coroutine_promise_proxy (tree decl)
776 : : {
777 : 7215 : if (coroutine_info *info = get_coroutine_info (decl))
778 : 7215 : return info->promise_proxy;
779 : :
780 : : return NULL_TREE;
781 : : }
782 : :
783 : : static tree
784 : 1292 : get_coroutine_from_address (tree decl)
785 : : {
786 : 1292 : if (coroutine_info *info = get_coroutine_info (decl))
787 : 0 : return info->from_address;
788 : :
789 : : return NULL_TREE;
790 : : }
791 : :
792 : : static tree
793 : 11273 : lookup_promise_method (tree fndecl, tree member_id, location_t loc,
794 : : bool musthave)
795 : : {
796 : 11273 : tree promise = get_coroutine_promise_type (fndecl);
797 : 11273 : tree pm_memb
798 : 11273 : = lookup_member (promise, member_id,
799 : : /*protect=*/1, /*want_type=*/0, tf_warning_or_error);
800 : 11273 : if (musthave && pm_memb == NULL_TREE)
801 : : {
802 : 7 : error_at (loc, "no member named %qE in %qT", member_id, promise);
803 : 7 : return error_mark_node;
804 : : }
805 : : return pm_memb;
806 : : }
807 : :
808 : : /* Build an expression of the form p.method (args) where the p is a promise
809 : : object for the current coroutine.
810 : : OBJECT is the promise object instance to use, it may be NULL, in which case
811 : : we will use the promise_proxy instance for this coroutine.
812 : : ARGS may be NULL, for empty parm lists. */
813 : :
814 : : static tree
815 : 7927 : coro_build_promise_expression (tree fn, tree promise_obj, tree member_id,
816 : : location_t loc, vec<tree, va_gc> **args,
817 : : bool musthave)
818 : : {
819 : 7927 : tree meth = lookup_promise_method (fn, member_id, loc, musthave);
820 : 7927 : if (meth == error_mark_node)
821 : : return error_mark_node;
822 : :
823 : : /* If we don't find it, and it isn't needed, an empty return is OK. */
824 : 7921 : if (!meth)
825 : : return NULL_TREE;
826 : :
827 : 7039 : tree promise
828 : 7039 : = promise_obj ? promise_obj
829 : 4419 : : get_coroutine_promise_proxy (current_function_decl);
830 : 7039 : tree expr;
831 : 7039 : if (BASELINK_P (meth))
832 : 6927 : expr = build_new_method_call (promise, meth, args, NULL_TREE,
833 : : LOOKUP_NORMAL, NULL, tf_warning_or_error);
834 : : else
835 : : {
836 : 112 : expr = build_class_member_access_expr (promise, meth, NULL_TREE,
837 : : true, tf_warning_or_error);
838 : 112 : vec<tree, va_gc> *real_args;
839 : 112 : if (!args)
840 : 80 : real_args = make_tree_vector ();
841 : : else
842 : 32 : real_args = *args;
843 : 112 : expr = build_op_call (expr, &real_args, tf_warning_or_error);
844 : : }
845 : : return expr;
846 : : }
847 : :
848 : : /* Caching get for the expression p.return_void (). */
849 : :
850 : : static tree
851 : 1628 : get_coroutine_return_void_expr (tree decl, location_t loc, bool musthave)
852 : : {
853 : 1628 : if (coroutine_info *info = get_coroutine_info (decl))
854 : : {
855 : : /* If we don't have it try to build it. */
856 : 1628 : if (!info->return_void)
857 : 1305 : info->return_void
858 : 1305 : = coro_build_promise_expression (current_function_decl, NULL,
859 : : coro_return_void_identifier,
860 : : loc, NULL, musthave);
861 : : /* Don't return an error if it's an optional call. */
862 : 1628 : if (!musthave && info->return_void == error_mark_node)
863 : : return NULL_TREE;
864 : 1627 : return info->return_void;
865 : : }
866 : 0 : return musthave ? error_mark_node : NULL_TREE;
867 : : }
868 : :
869 : : /* Lookup an Awaitable member, which should be await_ready, await_suspend
870 : : or await_resume. */
871 : :
872 : : static tree
873 : 10672 : lookup_awaitable_member (tree await_type, tree member_id, location_t loc)
874 : : {
875 : 10672 : tree aw_memb
876 : 10672 : = lookup_member (await_type, member_id,
877 : : /*protect=*/1, /*want_type=*/0, tf_warning_or_error);
878 : 10672 : if (aw_memb == NULL_TREE)
879 : : {
880 : 5 : error_at (loc, "no member named %qE in %qT", member_id, await_type);
881 : 5 : return error_mark_node;
882 : : }
883 : : return aw_memb;
884 : : }
885 : :
886 : : /* Here we check the constraints that are common to all keywords (since the
887 : : presence of a coroutine keyword makes the function into a coroutine). */
888 : :
889 : : static bool
890 : 3775 : coro_common_keyword_context_valid_p (tree fndecl, location_t kw_loc,
891 : : const char *kw_name)
892 : : {
893 : 3775 : if (fndecl == NULL_TREE)
894 : : {
895 : 4 : error_at (kw_loc, "%qs cannot be used outside a function", kw_name);
896 : 4 : return false;
897 : : }
898 : :
899 : : /* This is arranged in order of prohibitions in the std. */
900 : 3771 : if (DECL_MAIN_P (fndecl))
901 : : {
902 : : /* [basic.start.main] 3. The function main shall not be a coroutine. */
903 : 3 : error_at (kw_loc, "%qs cannot be used in the %<main%> function",
904 : : kw_name);
905 : 3 : return false;
906 : : }
907 : :
908 : 3768 : if (DECL_DECLARED_CONSTEXPR_P (fndecl))
909 : : {
910 : 5 : cp_function_chain->invalid_constexpr = true;
911 : 5 : if (!is_instantiation_of_constexpr (fndecl))
912 : : {
913 : : /* [dcl.constexpr] 3.3 it shall not be a coroutine. */
914 : 3 : error_at (kw_loc, "%qs cannot be used in a %<constexpr%> function",
915 : : kw_name);
916 : 3 : return false;
917 : : }
918 : : }
919 : :
920 : 3765 : if (FNDECL_USED_AUTO (fndecl))
921 : : {
922 : : /* [dcl.spec.auto] 15. A function declared with a return type that uses
923 : : a placeholder type shall not be a coroutine. */
924 : 6 : error_at (kw_loc,
925 : : "%qs cannot be used in a function with a deduced return type",
926 : : kw_name);
927 : 6 : return false;
928 : : }
929 : :
930 : 3759 : if (varargs_function_p (fndecl))
931 : : {
932 : : /* [dcl.fct.def.coroutine] The parameter-declaration-clause of the
933 : : coroutine shall not terminate with an ellipsis that is not part
934 : : of a parameter-declaration. */
935 : 3 : error_at (kw_loc,
936 : : "%qs cannot be used in a varargs function", kw_name);
937 : 3 : return false;
938 : : }
939 : :
940 : 7512 : if (DECL_CONSTRUCTOR_P (fndecl))
941 : : {
942 : : /* [class.ctor] 7. a constructor shall not be a coroutine. */
943 : 3 : error_at (kw_loc, "%qs cannot be used in a constructor", kw_name);
944 : 3 : return false;
945 : : }
946 : :
947 : 3753 : if (DECL_DESTRUCTOR_P (fndecl))
948 : : {
949 : : /* [class.dtor] 21. a destructor shall not be a coroutine. */
950 : 3 : error_at (kw_loc, "%qs cannot be used in a destructor", kw_name);
951 : 3 : return false;
952 : : }
953 : :
954 : : return true;
955 : : }
956 : :
957 : : /* Here we check the constraints that are not per keyword. */
958 : :
959 : : static bool
960 : 1323 : coro_function_valid_p (tree fndecl)
961 : : {
962 : 1323 : location_t f_loc = DECL_SOURCE_LOCATION (fndecl);
963 : :
964 : : /* For cases where fundamental information cannot be found, e.g. the
965 : : coroutine traits are missing, we need to punt early. */
966 : 1323 : if (!coro_promise_type_found_p (fndecl, f_loc))
967 : : return false;
968 : :
969 : : /* Since we think the function is a coroutine, that implies we parsed
970 : : a keyword that triggered this. Keywords check promise validity for
971 : : their context and thus the promise type should be known at this point. */
972 : 1309 : if (get_coroutine_handle_type (fndecl) == NULL_TREE
973 : 2613 : || get_coroutine_promise_type (fndecl) == NULL_TREE)
974 : 5 : return false;
975 : :
976 : 1304 : if (current_function_returns_value || current_function_returns_null)
977 : : {
978 : : /* TODO: record or extract positions of returns (and the first coro
979 : : keyword) so that we can add notes to the diagnostic about where
980 : : the bad keyword is and what made the function into a coro. */
981 : 1 : error_at (f_loc, "a %<return%> statement is not allowed in coroutine;"
982 : : " did you mean %<co_return%>?");
983 : 1 : return false;
984 : : }
985 : :
986 : : return true;
987 : : }
988 : :
989 : : enum suspend_point_kind {
990 : : CO_AWAIT_SUSPEND_POINT = 0,
991 : : CO_YIELD_SUSPEND_POINT,
992 : : INITIAL_SUSPEND_POINT,
993 : : FINAL_SUSPEND_POINT
994 : : };
995 : :
996 : : /* Helper function to build a named variable for the temps we use for each
997 : : await point. The root of the name is determined by SUSPEND_KIND, and
998 : : the variable is of type V_TYPE. The awaitable number is reset each time
999 : : we encounter a final suspend. */
1000 : :
1001 : : static tree
1002 : 3473 : get_awaitable_var (suspend_point_kind suspend_kind, tree v_type)
1003 : : {
1004 : 3473 : auto cinfo = get_coroutine_info (current_function_decl);
1005 : 3473 : gcc_checking_assert (cinfo);
1006 : 3473 : char *buf;
1007 : 3473 : switch (suspend_kind)
1008 : : {
1009 : 540 : default: buf = xasprintf ("Aw%d", cinfo->awaitable_number++); break;
1010 : 337 : case CO_YIELD_SUSPEND_POINT:
1011 : 337 : buf = xasprintf ("Yd%d", cinfo->awaitable_number++);
1012 : 337 : break;
1013 : 1300 : case INITIAL_SUSPEND_POINT: buf = xasprintf ("Is"); break;
1014 : 1296 : case FINAL_SUSPEND_POINT: buf = xasprintf ("Fs"); break;
1015 : : }
1016 : 3473 : tree ret = get_identifier (buf);
1017 : 3473 : free (buf);
1018 : 3473 : ret = build_lang_decl (VAR_DECL, ret, v_type);
1019 : 3473 : DECL_ARTIFICIAL (ret) = true;
1020 : 3473 : return ret;
1021 : : }
1022 : :
1023 : : /* Helpers to diagnose missing noexcept on final await expressions. */
1024 : :
1025 : : static bool
1026 : 5934 : coro_diagnose_throwing_fn (tree fndecl)
1027 : : {
1028 : 5934 : if (!TYPE_NOTHROW_P (TREE_TYPE (fndecl)))
1029 : : {
1030 : 7 : auto_diagnostic_group d;
1031 : 7 : location_t f_loc = cp_expr_loc_or_loc (fndecl,
1032 : 7 : DECL_SOURCE_LOCATION (fndecl));
1033 : 7 : error_at (f_loc, "the expression %qE is required to be non-throwing",
1034 : : fndecl);
1035 : 7 : inform (f_loc, "must be declared with %<noexcept(true)%>");
1036 : 7 : return true;
1037 : 7 : }
1038 : : return false;
1039 : : }
1040 : :
1041 : : static bool
1042 : 1301 : coro_diagnose_throwing_final_aw_expr (tree expr)
1043 : : {
1044 : 1301 : if (TREE_CODE (expr) == TARGET_EXPR)
1045 : 1300 : expr = TARGET_EXPR_INITIAL (expr);
1046 : 1301 : tree fn = NULL_TREE;
1047 : 1301 : if (TREE_CODE (expr) == CALL_EXPR)
1048 : 523 : fn = CALL_EXPR_FN (expr);
1049 : 778 : else if (TREE_CODE (expr) == AGGR_INIT_EXPR)
1050 : 778 : fn = AGGR_INIT_EXPR_FN (expr);
1051 : 0 : else if (TREE_CODE (expr) == CONSTRUCTOR)
1052 : : return false;
1053 : : else
1054 : : {
1055 : 0 : gcc_checking_assert (0 && "unhandled expression type");
1056 : : return false;
1057 : : }
1058 : 1301 : fn = TREE_OPERAND (fn, 0);
1059 : 1301 : return coro_diagnose_throwing_fn (fn);
1060 : : }
1061 : :
1062 : : /* Build a co_await suitable for later expansion. */
1063 : :
1064 : : tree
1065 : 108 : build_template_co_await_expr (location_t kw, tree type, tree expr, tree kind)
1066 : : {
1067 : 108 : tree aw_expr = build5_loc (kw, CO_AWAIT_EXPR, type, expr,
1068 : : NULL_TREE, NULL_TREE, NULL_TREE,
1069 : : kind);
1070 : 108 : TREE_SIDE_EFFECTS (aw_expr) = true;
1071 : 108 : return aw_expr;
1072 : : }
1073 : :
1074 : :
1075 : : /* This performs [expr.await] bullet 3.3 and validates the interface obtained.
1076 : : It is also used to build the initial and final suspend points.
1077 : :
1078 : : 'a', 'o' and 'e' are used as per the description in the section noted.
1079 : :
1080 : : A, the original yield/await expr, is found at source location LOC.
1081 : :
1082 : : We will be constructing a CO_AWAIT_EXPR for a suspend point of one of
1083 : : the four suspend_point_kind kinds. This is indicated by SUSPEND_KIND.
1084 : :
1085 : : In the case that we're processing a template declaration, we can't save
1086 : : actual awaiter expressions as the frame type will differ between
1087 : : instantiations, but we can generate them to type-check them and compute the
1088 : : resulting expression type. In those cases, we will return a
1089 : : template-appropriate CO_AWAIT_EXPR and throw away the rest of the results.
1090 : : Such an expression requires the original co_await operand unaltered. Pass
1091 : : it as ORIG_OPERAND. If it is the same as 'a', you can pass NULL_TREE (the
1092 : : default) to use 'a' as the value. */
1093 : :
1094 : : static tree
1095 : 3566 : build_co_await (location_t loc, tree a, suspend_point_kind suspend_kind,
1096 : : tree orig_operand = NULL_TREE)
1097 : : {
1098 : 3566 : if (orig_operand == NULL_TREE)
1099 : 2943 : orig_operand = a;
1100 : :
1101 : : /* Try and overload of operator co_await, .... */
1102 : 3566 : tree o;
1103 : 3566 : if (MAYBE_CLASS_TYPE_P (TREE_TYPE (a)))
1104 : : {
1105 : 3561 : o = build_new_op (loc, CO_AWAIT_EXPR, LOOKUP_NORMAL, a, NULL_TREE,
1106 : : NULL_TREE, NULL_TREE, NULL, tf_warning_or_error);
1107 : : /* If no viable functions are found, o is a. */
1108 : 3561 : if (!o || o == error_mark_node)
1109 : : o = a;
1110 : 118 : else if (flag_exceptions && suspend_kind == FINAL_SUSPEND_POINT)
1111 : : {
1112 : : /* We found an overload for co_await(), diagnose throwing cases. */
1113 : 7 : if (TREE_CODE (o) == TARGET_EXPR
1114 : 7 : && coro_diagnose_throwing_final_aw_expr (o))
1115 : 1 : return error_mark_node;
1116 : :
1117 : : /* We now know that the final suspend object is distinct from the
1118 : : final awaiter, so check for a non-throwing DTOR where needed. */
1119 : 6 : if (tree dummy = cxx_maybe_build_cleanup (a, tf_none))
1120 : : {
1121 : 5 : if (CONVERT_EXPR_P (dummy))
1122 : 0 : dummy = TREE_OPERAND (dummy, 0);
1123 : 5 : dummy = TREE_OPERAND (CALL_EXPR_FN (dummy), 0);
1124 : 5 : if (coro_diagnose_throwing_fn (dummy))
1125 : 1 : return error_mark_node;
1126 : : }
1127 : : }
1128 : : }
1129 : : else
1130 : : o = a; /* This is most likely about to fail anyway. */
1131 : :
1132 : 3564 : tree o_type = TREE_TYPE (o);
1133 : 3564 : if (o_type && !VOID_TYPE_P (o_type))
1134 : 3563 : o_type = complete_type_or_else (o_type, o);
1135 : :
1136 : 3563 : if (!o_type)
1137 : 3 : return error_mark_node;
1138 : :
1139 : 3561 : if (TREE_CODE (o_type) != RECORD_TYPE)
1140 : : {
1141 : 2 : error_at (loc, "awaitable type %qT is not a structure",
1142 : : o_type);
1143 : 2 : return error_mark_node;
1144 : : }
1145 : :
1146 : : /* Check for required awaitable members and their types. */
1147 : 3559 : tree awrd_meth
1148 : 3559 : = lookup_awaitable_member (o_type, coro_await_ready_identifier, loc);
1149 : 3559 : if (!awrd_meth || awrd_meth == error_mark_node)
1150 : 1 : return error_mark_node;
1151 : 3558 : tree awsp_meth
1152 : 3558 : = lookup_awaitable_member (o_type, coro_await_suspend_identifier, loc);
1153 : 3558 : if (!awsp_meth || awsp_meth == error_mark_node)
1154 : 3 : return error_mark_node;
1155 : :
1156 : : /* The type of the co_await is the return type of the awaitable's
1157 : : await_resume, so we need to look that up. */
1158 : 3555 : tree awrs_meth
1159 : 3555 : = lookup_awaitable_member (o_type, coro_await_resume_identifier, loc);
1160 : 3555 : if (!awrs_meth || awrs_meth == error_mark_node)
1161 : 1 : return error_mark_node;
1162 : :
1163 : : /* [expr.await]/3.3 If o would be a prvalue, the temporary
1164 : : materialization conversion ([conv.rval]) is applied. */
1165 : 3554 : if (!glvalue_p (o))
1166 : 3473 : o = get_target_expr (o, tf_warning_or_error);
1167 : :
1168 : 3554 : tree e_proxy = o;
1169 : 3554 : if (glvalue_p (o))
1170 : : o = NULL_TREE; /* Use the existing entity. */
1171 : : else /* We need to materialise it. */
1172 : : {
1173 : 3473 : e_proxy = get_awaitable_var (suspend_kind, o_type);
1174 : 3473 : o = cp_build_init_expr (loc, e_proxy, o);
1175 : 3473 : e_proxy = convert_from_reference (e_proxy);
1176 : : }
1177 : :
1178 : : /* I suppose we could check that this is contextually convertible to bool. */
1179 : 3554 : tree awrd_func = NULL_TREE;
1180 : 3554 : tree awrd_call
1181 : 3554 : = build_new_method_call (e_proxy, awrd_meth, NULL, NULL_TREE, LOOKUP_NORMAL,
1182 : : &awrd_func, tf_warning_or_error);
1183 : :
1184 : 3554 : if (!awrd_func || !awrd_call || awrd_call == error_mark_node)
1185 : 0 : return error_mark_node;
1186 : :
1187 : : /* The suspend method may return one of three types:
1188 : : 1. void (no special action needed).
1189 : : 2. bool (if true, we don't need to suspend).
1190 : : 3. a coroutine handle, we execute the handle.resume() call. */
1191 : 3554 : tree awsp_func = NULL_TREE;
1192 : 3554 : tree h_proxy = get_coroutine_self_handle_proxy (current_function_decl);
1193 : 3554 : vec<tree, va_gc> *args = make_tree_vector_single (h_proxy);
1194 : 3554 : tree awsp_call
1195 : 3554 : = build_new_method_call (e_proxy, awsp_meth, &args, NULL_TREE,
1196 : : LOOKUP_NORMAL, &awsp_func, tf_warning_or_error);
1197 : :
1198 : 3554 : release_tree_vector (args);
1199 : 3554 : if (!awsp_func || !awsp_call || awsp_call == error_mark_node)
1200 : 0 : return error_mark_node;
1201 : :
1202 : 3554 : bool ok = false;
1203 : 3554 : tree susp_return_type = TREE_TYPE (TREE_TYPE (awsp_func));
1204 : 3554 : if (same_type_p (susp_return_type, void_type_node))
1205 : : ok = true;
1206 : 86 : else if (same_type_p (susp_return_type, boolean_type_node))
1207 : : ok = true;
1208 : 63 : else if (TREE_CODE (susp_return_type) == RECORD_TYPE
1209 : 63 : && CLASS_TYPE_P (susp_return_type)
1210 : 126 : && CLASSTYPE_TEMPLATE_INFO (susp_return_type))
1211 : : {
1212 : 62 : tree tt = CLASSTYPE_TI_TEMPLATE (susp_return_type);
1213 : 62 : if (tt == coro_handle_templ)
1214 : : ok = true;
1215 : : }
1216 : :
1217 : : if (!ok)
1218 : : {
1219 : 1 : error_at (loc, "%<await_suspend%> must return %<void%>, %<bool%> or"
1220 : : " a coroutine handle");
1221 : 1 : return error_mark_node;
1222 : : }
1223 : :
1224 : : /* Finally, the type of e.await_resume() is the co_await's type. */
1225 : 3553 : tree awrs_func = NULL_TREE;
1226 : 3553 : tree awrs_call
1227 : 3553 : = build_new_method_call (e_proxy, awrs_meth, NULL, NULL_TREE, LOOKUP_NORMAL,
1228 : : &awrs_func, tf_warning_or_error);
1229 : :
1230 : 3553 : if (!awrs_func || !awrs_call || awrs_call == error_mark_node)
1231 : 0 : return error_mark_node;
1232 : :
1233 : 3553 : if (flag_exceptions && suspend_kind == FINAL_SUSPEND_POINT)
1234 : : {
1235 : 1289 : if (coro_diagnose_throwing_fn (awrd_func))
1236 : 1 : return error_mark_node;
1237 : 1288 : if (coro_diagnose_throwing_fn (awsp_func))
1238 : 1 : return error_mark_node;
1239 : 1287 : if (coro_diagnose_throwing_fn (awrs_func))
1240 : 1 : return error_mark_node;
1241 : 1286 : if (tree dummy = cxx_maybe_build_cleanup (e_proxy, tf_none))
1242 : : {
1243 : 764 : if (CONVERT_EXPR_P (dummy))
1244 : 0 : dummy = TREE_OPERAND (dummy, 0);
1245 : 764 : dummy = TREE_OPERAND (CALL_EXPR_FN (dummy), 0);
1246 : 764 : if (coro_diagnose_throwing_fn (dummy))
1247 : 1 : return error_mark_node;
1248 : : }
1249 : : }
1250 : :
1251 : : /* We now have three call expressions, in terms of the promise, handle and
1252 : : 'e' proxies. Save them in the await expression for later expansion. */
1253 : :
1254 : 3549 : tree awaiter_calls = make_tree_vec (3);
1255 : 3549 : TREE_VEC_ELT (awaiter_calls, 0) = awrd_call; /* await_ready(). */
1256 : 3549 : TREE_VEC_ELT (awaiter_calls, 1) = awsp_call; /* await_suspend(). */
1257 : 3549 : tree te = NULL_TREE;
1258 : 3549 : if (TREE_CODE (awrs_call) == TARGET_EXPR)
1259 : : {
1260 : 18 : te = awrs_call;
1261 : 18 : awrs_call = TREE_OPERAND (awrs_call, 1);
1262 : : }
1263 : 3549 : TREE_VEC_ELT (awaiter_calls, 2) = awrs_call; /* await_resume(). */
1264 : :
1265 : 3549 : if (REFERENCE_REF_P (e_proxy))
1266 : 29 : e_proxy = TREE_OPERAND (e_proxy, 0);
1267 : :
1268 : 3549 : tree awrs_type = TREE_TYPE (TREE_TYPE (awrs_func));
1269 : 7098 : tree suspend_kind_cst = build_int_cst (integer_type_node,
1270 : 3549 : (int) suspend_kind);
1271 : 3549 : tree await_expr = build5_loc (loc, CO_AWAIT_EXPR,
1272 : : awrs_type,
1273 : : a, e_proxy, o, awaiter_calls,
1274 : : suspend_kind_cst);
1275 : 3549 : TREE_SIDE_EFFECTS (await_expr) = true;
1276 : 3549 : if (te)
1277 : : {
1278 : 18 : TREE_OPERAND (te, 1) = await_expr;
1279 : 18 : TREE_SIDE_EFFECTS (te) = true;
1280 : 18 : await_expr = te;
1281 : : }
1282 : 3549 : SET_EXPR_LOCATION (await_expr, loc);
1283 : :
1284 : 3549 : if (processing_template_decl)
1285 : 14 : return build_template_co_await_expr (loc, awrs_type, orig_operand,
1286 : 14 : suspend_kind_cst);
1287 : 3535 : return convert_from_reference (await_expr);
1288 : : }
1289 : :
1290 : : /* Returns true iff EXPR or the TRAITS_CLASS, which should be a
1291 : : coroutine_traits instance, are dependent. In those cases, we can't decide
1292 : : what the types of our co_{await,yield,return} expressions are, so we defer
1293 : : expansion entirely. */
1294 : :
1295 : : static bool
1296 : 3734 : coro_dependent_p (tree expr, tree traits_class)
1297 : : {
1298 : 3734 : return type_dependent_expression_p (expr)
1299 : 3734 : || dependent_type_p (traits_class);
1300 : : }
1301 : :
1302 : : tree
1303 : 729 : finish_co_await_expr (location_t kw, tree expr)
1304 : : {
1305 : 729 : if (!expr || error_operand_p (expr))
1306 : 0 : return error_mark_node;
1307 : :
1308 : 729 : if (!coro_common_keyword_context_valid_p (current_function_decl, kw,
1309 : : "co_await"))
1310 : 9 : return error_mark_node;
1311 : :
1312 : : /* The current function has now become a coroutine, if it wasn't already. */
1313 : 720 : DECL_COROUTINE_P (current_function_decl) = 1;
1314 : :
1315 : : /* This function will appear to have no return statement, even if it
1316 : : is declared to return non-void (most likely). This is correct - we
1317 : : synthesize the return for the ramp in the compiler. So suppress any
1318 : : extraneous warnings during substitution. */
1319 : 720 : suppress_warning (current_function_decl, OPT_Wreturn_type);
1320 : :
1321 : : /* Prepare for coroutine transformations. */
1322 : 720 : if (!ensure_coro_initialized (kw))
1323 : 2 : return error_mark_node;
1324 : :
1325 : : /* Get our traits class. */
1326 : 718 : tree traits_class = coro_get_traits_class (current_function_decl, kw);
1327 : :
1328 : : /* Defer expansion when we are processing a template, unless the traits type
1329 : : and expression would not be dependent. In the case that the types are
1330 : : not dependent but we are processing a template declaration, we will do
1331 : : most of the computation but throw away the results (except for the
1332 : : await_resume type). Otherwise, if our co_await is type-dependent
1333 : : (i.e. the promise type or operand type is dependent), we can't do much,
1334 : : and just return early with a NULL_TREE type (indicating that we cannot
1335 : : compute the type yet). */
1336 : 718 : if (coro_dependent_p (expr, traits_class))
1337 : 94 : return build_template_co_await_expr (kw, NULL_TREE, expr,
1338 : 94 : integer_zero_node);
1339 : :
1340 : : /* We must be able to look up the "await_transform" method in the scope of
1341 : : the promise type, and obtain its return type. */
1342 : 624 : if (!coro_promise_type_found_p (current_function_decl, kw))
1343 : 1 : return error_mark_node;
1344 : :
1345 : : /* [expr.await] 3.2
1346 : : The incoming cast expression might be transformed by a promise
1347 : : 'await_transform()'. */
1348 : 623 : tree at_meth
1349 : 623 : = lookup_promise_method (current_function_decl,
1350 : : coro_await_transform_identifier, kw,
1351 : : /*musthave=*/false);
1352 : 623 : if (at_meth == error_mark_node)
1353 : : return error_mark_node;
1354 : :
1355 : 623 : tree a = expr;
1356 : 623 : if (at_meth)
1357 : : {
1358 : : /* try to build a = p.await_transform (e). */
1359 : 202 : vec<tree, va_gc> *args = make_tree_vector_single (expr);
1360 : 404 : a = build_new_method_call (get_coroutine_promise_proxy (
1361 : : current_function_decl),
1362 : : at_meth, &args, NULL_TREE, LOOKUP_NORMAL,
1363 : : NULL, tf_warning_or_error);
1364 : :
1365 : : /* As I read the section.
1366 : : We saw an await_transform method, so it's mandatory that we replace
1367 : : expr with p.await_transform (expr), therefore if the method call fails
1368 : : (presumably, we don't have suitable arguments) then this part of the
1369 : : process fails. */
1370 : 202 : if (a == error_mark_node)
1371 : 0 : return error_mark_node;
1372 : : }
1373 : :
1374 : : /* Now we want to build co_await a. */
1375 : 623 : return build_co_await (kw, a, CO_AWAIT_SUSPEND_POINT, expr);
1376 : : }
1377 : :
1378 : : /* Take the EXPR given and attempt to build:
1379 : : co_await p.yield_value (expr);
1380 : : per [expr.yield] para 1. */
1381 : :
1382 : : tree
1383 : 1484 : finish_co_yield_expr (location_t kw, tree expr)
1384 : : {
1385 : 1484 : if (!expr || error_operand_p (expr))
1386 : 0 : return error_mark_node;
1387 : :
1388 : : /* Check the general requirements and simple syntax errors. */
1389 : 1484 : if (!coro_common_keyword_context_valid_p (current_function_decl, kw,
1390 : : "co_yield"))
1391 : 9 : return error_mark_node;
1392 : :
1393 : : /* The current function has now become a coroutine, if it wasn't already. */
1394 : 1475 : DECL_COROUTINE_P (current_function_decl) = 1;
1395 : :
1396 : : /* This function will appear to have no return statement, even if it
1397 : : is declared to return non-void (most likely). This is correct - we
1398 : : synthesize the return for the ramp in the compiler. So suppress any
1399 : : extraneous warnings during substitution. */
1400 : 1475 : suppress_warning (current_function_decl, OPT_Wreturn_type);
1401 : :
1402 : : /* Prepare for coroutine transformations. */
1403 : 1475 : if (!ensure_coro_initialized (kw))
1404 : 4 : return error_mark_node;
1405 : :
1406 : : /* Get our traits class. */
1407 : 1471 : tree traits_class = coro_get_traits_class (current_function_decl, kw);
1408 : :
1409 : : /* Defer expansion when we are processing a template; see note in
1410 : : finish_co_await_expr. Also note that a yield is equivalent to
1411 : :
1412 : : co_await p.yield_value(EXPR)
1413 : :
1414 : : If either p or EXPR are type-dependent, then the whole expression is
1415 : : certainly type-dependent, and we can't proceed. */
1416 : 1471 : if (coro_dependent_p (expr, traits_class))
1417 : 1129 : return build2_loc (kw, CO_YIELD_EXPR, NULL_TREE, expr, NULL_TREE);
1418 : :
1419 : 342 : if (!coro_promise_type_found_p (current_function_decl, kw))
1420 : : /* We must be able to look up the "yield_value" method in the scope of
1421 : : the promise type, and obtain its return type. */
1422 : 2 : return error_mark_node;
1423 : :
1424 : : /* [expr.yield] / 1
1425 : : Let e be the operand of the yield-expression and p be an lvalue naming
1426 : : the promise object of the enclosing coroutine, then the yield-expression
1427 : : is equivalent to the expression co_await p.yield_value(e).
1428 : : build p.yield_value(e): */
1429 : 340 : vec<tree, va_gc> *args = make_tree_vector_single (expr);
1430 : 340 : tree yield_call
1431 : 340 : = coro_build_promise_expression (current_function_decl, NULL,
1432 : : coro_yield_value_identifier, kw,
1433 : : &args, /*musthave=*/true);
1434 : 340 : release_tree_vector (args);
1435 : :
1436 : : /* Now build co_await p.yield_value (e).
1437 : : Noting that for co_yield, there is no evaluation of any potential
1438 : : promise transform_await(), so we call build_co_await directly. */
1439 : :
1440 : 340 : tree op = build_co_await (kw, yield_call, CO_YIELD_SUSPEND_POINT);
1441 : 340 : if (op != error_mark_node)
1442 : : {
1443 : 337 : if (REFERENCE_REF_P (op))
1444 : 0 : op = TREE_OPERAND (op, 0);
1445 : : /* If the await expression is wrapped in a TARGET_EXPR, then transfer
1446 : : that wrapper to the CO_YIELD_EXPR, since this is just a proxy for
1447 : : its contained await. Otherwise, just build the CO_YIELD_EXPR. */
1448 : 337 : if (TREE_CODE (op) == TARGET_EXPR)
1449 : : {
1450 : 1 : tree t = TREE_OPERAND (op, 1);
1451 : 1 : t = build2_loc (kw, CO_YIELD_EXPR, TREE_TYPE (t), expr, t);
1452 : 1 : TREE_OPERAND (op, 1) = t;
1453 : : }
1454 : : else
1455 : 336 : op = build2_loc (kw, CO_YIELD_EXPR, TREE_TYPE (op), expr, op);
1456 : 337 : TREE_SIDE_EFFECTS (op) = 1;
1457 : 337 : op = convert_from_reference (op);
1458 : : }
1459 : :
1460 : : return op;
1461 : : }
1462 : :
1463 : : /* Check and build a co_return statement.
1464 : : First that it's valid to have a co_return keyword here.
1465 : : If it is, then check and build the p.return_{void(),value(expr)}.
1466 : : These are built against a proxy for the promise, which will be filled
1467 : : in with the actual frame version when the function is transformed. */
1468 : :
1469 : : tree
1470 : 1562 : finish_co_return_stmt (location_t kw, tree expr)
1471 : : {
1472 : 1562 : if (expr)
1473 : 1228 : STRIP_ANY_LOCATION_WRAPPER (expr);
1474 : :
1475 : 1562 : if (error_operand_p (expr))
1476 : 0 : return error_mark_node;
1477 : :
1478 : : /* If it fails the following test, the function is not permitted to be a
1479 : : coroutine, so the co_return statement is erroneous. */
1480 : 1562 : if (!coro_common_keyword_context_valid_p (current_function_decl, kw,
1481 : : "co_return"))
1482 : 7 : return error_mark_node;
1483 : :
1484 : : /* The current function has now become a coroutine, if it wasn't
1485 : : already. */
1486 : 1555 : DECL_COROUTINE_P (current_function_decl) = 1;
1487 : :
1488 : : /* This function will appear to have no return statement, even if it
1489 : : is declared to return non-void (most likely). This is correct - we
1490 : : synthesize the return for the ramp in the compiler. So suppress any
1491 : : extraneous warnings during substitution. */
1492 : 1555 : suppress_warning (current_function_decl, OPT_Wreturn_type);
1493 : :
1494 : : /* Prepare for coroutine transformations. */
1495 : 1555 : if (!ensure_coro_initialized (kw))
1496 : 10 : return error_mark_node;
1497 : :
1498 : : /* Get our traits class. */
1499 : 1545 : tree traits_class = coro_get_traits_class (current_function_decl, kw);
1500 : :
1501 : 1545 : if (processing_template_decl
1502 : 1545 : && check_for_bare_parameter_packs (expr))
1503 : 0 : return error_mark_node;
1504 : :
1505 : : /* Defer expansion when we must and are processing a template; see note in
1506 : : finish_co_await_expr. */
1507 : 1545 : if (coro_dependent_p (expr, traits_class))
1508 : : {
1509 : : /* co_return expressions are always void type, regardless of the
1510 : : expression type. */
1511 : 156 : expr = build2_loc (kw, CO_RETURN_EXPR, void_type_node,
1512 : : expr, NULL_TREE);
1513 : 156 : expr = maybe_cleanup_point_expr_void (expr);
1514 : 156 : return add_stmt (expr);
1515 : : }
1516 : :
1517 : 1389 : if (!coro_promise_type_found_p (current_function_decl, kw))
1518 : 6 : return error_mark_node;
1519 : :
1520 : : /* Suppress -Wreturn-type for co_return, we need to check indirectly
1521 : : whether the promise type has a suitable return_void/return_value. */
1522 : 1383 : suppress_warning (current_function_decl, OPT_Wreturn_type);
1523 : :
1524 : 1383 : if (!processing_template_decl && warn_sequence_point)
1525 : 3 : verify_sequence_points (expr);
1526 : :
1527 : 1383 : if (expr)
1528 : : {
1529 : : /* If we had an id-expression obfuscated by force_paren_expr, we need
1530 : : to undo it so we can try to treat it as an rvalue below. */
1531 : 1068 : expr = maybe_undo_parenthesized_ref (expr);
1532 : :
1533 : 1068 : if (error_operand_p (expr))
1534 : 0 : return error_mark_node;
1535 : : }
1536 : :
1537 : : /* If the promise object doesn't have the correct return call then
1538 : : there's a mis-match between the co_return <expr> and this. */
1539 : 315 : tree co_ret_call = error_mark_node;
1540 : 1068 : if (expr == NULL_TREE || VOID_TYPE_P (TREE_TYPE (expr)))
1541 : 326 : co_ret_call
1542 : 326 : = get_coroutine_return_void_expr (current_function_decl, kw, true);
1543 : : else
1544 : : {
1545 : : /* [class.copy.elision] / 3.
1546 : : An implicitly movable entity is a variable of automatic storage
1547 : : duration that is either a non-volatile object or an rvalue reference
1548 : : to a non-volatile object type. For such objects in the context of
1549 : : the co_return, the overload resolution should be carried out first
1550 : : treating the object as an rvalue, if that fails, then we fall back
1551 : : to regular overload resolution. */
1552 : :
1553 : 1057 : tree arg = expr;
1554 : 1057 : if (tree moved = treat_lvalue_as_rvalue_p (expr, /*return*/true))
1555 : 245 : arg = moved;
1556 : :
1557 : 1057 : releasing_vec args = make_tree_vector_single (arg);
1558 : 1057 : co_ret_call
1559 : 1057 : = coro_build_promise_expression (current_function_decl, NULL,
1560 : : coro_return_value_identifier, kw,
1561 : : &args, /*musthave=*/true);
1562 : 1057 : }
1563 : :
1564 : : /* Makes no sense for a co-routine really. */
1565 : 1383 : if (TREE_THIS_VOLATILE (current_function_decl))
1566 : 0 : warning_at (kw, 0,
1567 : : "function declared %<noreturn%> has a"
1568 : : " %<co_return%> statement");
1569 : :
1570 : 1383 : expr = build2_loc (kw, CO_RETURN_EXPR, void_type_node, expr, co_ret_call);
1571 : 1383 : expr = maybe_cleanup_point_expr_void (expr);
1572 : 1383 : return add_stmt (expr);
1573 : : }
1574 : :
1575 : : /* We need to validate the arguments to __builtin_coro_promise, since the
1576 : : second two must be constant, and the builtins machinery doesn't seem to
1577 : : deal with that properly. */
1578 : :
1579 : : tree
1580 : 3182190 : coro_validate_builtin_call (tree call, tsubst_flags_t)
1581 : : {
1582 : 3182190 : tree fn = TREE_OPERAND (CALL_EXPR_FN (call), 0);
1583 : :
1584 : 3182190 : gcc_checking_assert (DECL_BUILT_IN_CLASS (fn) == BUILT_IN_NORMAL);
1585 : 3182190 : switch (DECL_FUNCTION_CODE (fn))
1586 : : {
1587 : : default:
1588 : : return call;
1589 : :
1590 : 6323 : case BUILT_IN_CORO_PROMISE:
1591 : 6323 : {
1592 : : /* Argument 0 is already checked by the normal built-in machinery
1593 : : Argument 1 must be a constant of size type. It probably makes
1594 : : little sense if it's not a power of 2, but that isn't specified
1595 : : formally. */
1596 : 6323 : tree arg = CALL_EXPR_ARG (call, 1);
1597 : 6323 : location_t loc = EXPR_LOCATION (arg);
1598 : :
1599 : : /* We expect alignof expressions in templates. */
1600 : 6323 : if (TREE_CODE (arg) == ALIGNOF_EXPR)
1601 : : ;
1602 : 1841 : else if (!TREE_CONSTANT (arg))
1603 : : {
1604 : 0 : error_at (loc, "the align argument to %<__builtin_coro_promise%>"
1605 : : " must be a constant");
1606 : 0 : return error_mark_node;
1607 : : }
1608 : : /* Argument 2 is the direction - to / from handle address to promise
1609 : : address. */
1610 : 6323 : arg = CALL_EXPR_ARG (call, 2);
1611 : 6323 : loc = EXPR_LOCATION (arg);
1612 : 6323 : if (!TREE_CONSTANT (arg))
1613 : : {
1614 : 0 : error_at (loc, "the direction argument to"
1615 : : " %<__builtin_coro_promise%> must be a constant");
1616 : 0 : return error_mark_node;
1617 : : }
1618 : : return call;
1619 : : break;
1620 : : }
1621 : : }
1622 : : }
1623 : :
1624 : : /* ================= Morph and Expand. =================
1625 : :
1626 : : The entry point here is morph_fn_to_coro () which is called from
1627 : : finish_function () when we have completed any template expansion.
1628 : :
1629 : : This is preceded by helper functions that implement the phases below.
1630 : :
1631 : : The process proceeds in four phases.
1632 : :
1633 : : A Initial framing.
1634 : : The user's function body is wrapped in the initial and final suspend
1635 : : points and we begin building the coroutine frame.
1636 : : We build empty decls for the actor and destroyer functions at this
1637 : : time too.
1638 : : When exceptions are enabled, the user's function body will also be
1639 : : wrapped in a try-catch block with the catch invoking the promise
1640 : : class 'unhandled_exception' method.
1641 : :
1642 : : B Analysis.
1643 : : The user's function body is analyzed to determine the suspend points,
1644 : : if any, and to capture local variables that might persist across such
1645 : : suspensions. In most cases, it is not necessary to capture compiler
1646 : : temporaries, since the tree-lowering nests the suspensions correctly.
1647 : : However, in the case of a captured reference, there is a lifetime
1648 : : extension to the end of the full expression - which can mean across a
1649 : : suspend point in which case it must be promoted to a frame variable.
1650 : :
1651 : : At the conclusion of analysis, we have a conservative frame layout and
1652 : : maps of the local variables to their frame entry points.
1653 : :
1654 : : C Build the ramp function.
1655 : : Carry out the allocation for the coroutine frame (NOTE; the actual size
1656 : : computation is deferred until late in the middle end to allow for future
1657 : : optimizations that will be allowed to elide unused frame entries).
1658 : : We build the return object.
1659 : :
1660 : : D Build and expand the actor and destroyer function bodies.
1661 : : The destroyer is a trivial shim that sets a bit to indicate that the
1662 : : destroy dispatcher should be used and then calls into the actor.
1663 : :
1664 : : The actor function is the implementation of the user's state machine.
1665 : : The current suspend point is noted in an index.
1666 : : Each suspend point is encoded as a pair of internal functions, one in
1667 : : the relevant dispatcher, and one representing the suspend point.
1668 : :
1669 : : During this process, the user's local variables and the proxies for the
1670 : : self-handle and the promise class instance are re-written to their
1671 : : coroutine frame equivalents.
1672 : :
1673 : : The complete bodies for the ramp, actor and destroy function are passed
1674 : : back to finish_function for folding and gimplification. */
1675 : :
1676 : : /* Helper to build a coroutine state frame access expression
1677 : : CORO_FP is a frame pointer
1678 : : MEMBER_ID is an identifier for a frame field
1679 : : PRESERVE_REF is true, the expression returned will have REFERENCE_TYPE if
1680 : : the MEMBER does.
1681 : : COMPLAIN is passed to the underlying functions. */
1682 : :
1683 : : static tree
1684 : 20473 : coro_build_frame_access_expr (tree coro_ref, tree member_id, bool preserve_ref,
1685 : : tsubst_flags_t complain)
1686 : : {
1687 : 20473 : gcc_checking_assert (INDIRECT_REF_P (coro_ref));
1688 : 20473 : tree fr_type = TREE_TYPE (coro_ref);
1689 : 20473 : tree mb = lookup_member (fr_type, member_id, /*protect=*/1, /*want_type=*/0,
1690 : : complain);
1691 : 20473 : if (!mb || mb == error_mark_node)
1692 : 0 : return error_mark_node;
1693 : 20473 : tree expr
1694 : 20473 : = build_class_member_access_expr (coro_ref, mb, NULL_TREE,
1695 : : preserve_ref, complain);
1696 : 20473 : return expr;
1697 : : }
1698 : :
1699 : : /* Helpers to build EXPR_STMT and void-cast EXPR_STMT, common ops. */
1700 : :
1701 : : static tree
1702 : 22662 : coro_build_expr_stmt (tree expr, location_t loc)
1703 : : {
1704 : 22662 : return maybe_cleanup_point_expr_void (build_stmt (loc, EXPR_STMT, expr));
1705 : : }
1706 : :
1707 : : static tree
1708 : 22662 : coro_build_cvt_void_expr_stmt (tree expr, location_t loc)
1709 : : {
1710 : 22662 : tree t = build1 (CONVERT_EXPR, void_type_node, expr);
1711 : 22662 : return coro_build_expr_stmt (t, loc);
1712 : : }
1713 : :
1714 : : /* Helpers to build an artificial var, with location LOC, NAME and TYPE, in
1715 : : CTX, and with initializer INIT. */
1716 : :
1717 : : static tree
1718 : 11769 : coro_build_artificial_var (location_t loc, tree name, tree type, tree ctx,
1719 : : tree init)
1720 : : {
1721 : 11769 : tree res = build_lang_decl (VAR_DECL, name, type);
1722 : 11769 : DECL_SOURCE_LOCATION (res) = loc;
1723 : 11769 : DECL_CONTEXT (res) = ctx;
1724 : 11769 : DECL_ARTIFICIAL (res) = true;
1725 : 11769 : DECL_INITIAL (res) = init;
1726 : 11769 : return res;
1727 : : }
1728 : :
1729 : : static tree
1730 : 3893 : coro_build_artificial_var (location_t loc, const char *name, tree type,
1731 : : tree ctx, tree init)
1732 : : {
1733 : 3893 : return coro_build_artificial_var (loc, get_identifier (name),
1734 : 3893 : type, ctx, init);
1735 : : }
1736 : :
1737 : :
1738 : : /* 2. Create a named label in the specified context. */
1739 : :
1740 : : static tree
1741 : 14810 : create_named_label_with_ctx (location_t loc, const char *name, tree ctx)
1742 : : {
1743 : 14810 : tree lab_id = get_identifier (name);
1744 : 14810 : tree lab = define_label (loc, lab_id);
1745 : 14810 : DECL_CONTEXT (lab) = ctx;
1746 : 14810 : DECL_ARTIFICIAL (lab) = true;
1747 : 14810 : TREE_USED (lab) = true;
1748 : 14810 : return lab;
1749 : : }
1750 : :
1751 : : struct proxy_replace
1752 : : {
1753 : : tree from, to;
1754 : : };
1755 : :
1756 : : static tree
1757 : 9773 : replace_proxy (tree *here, int *do_subtree, void *d)
1758 : : {
1759 : 9773 : proxy_replace *data = (proxy_replace *) d;
1760 : :
1761 : 9773 : if (*here == data->from)
1762 : : {
1763 : 208 : *here = data->to;
1764 : 208 : *do_subtree = 0;
1765 : : }
1766 : : else
1767 : 9565 : *do_subtree = 1;
1768 : 9773 : return NULL_TREE;
1769 : : }
1770 : :
1771 : : /* Support for expansion of co_await statements. */
1772 : :
1773 : : struct coro_aw_data
1774 : : {
1775 : : tree actor_fn; /* Decl for context. */
1776 : : tree coro_fp; /* Frame pointer var. */
1777 : : tree resume_idx; /* This is the index var in the frame. */
1778 : : tree i_a_r_c; /* initial suspend await_resume() was called if true. */
1779 : : tree self_h; /* This is a handle to the current coro (frame var). */
1780 : : tree cleanup; /* This is where to go once we complete local destroy. */
1781 : : tree cororet; /* This is where to go if we suspend. */
1782 : : tree corocont; /* This is where to go if we continue. */
1783 : : tree conthand; /* This is the handle for a continuation. */
1784 : : unsigned index; /* This is our current resume index. */
1785 : : };
1786 : :
1787 : : /* Lightweight search for the first await expression in tree-walk order.
1788 : : returns:
1789 : : The first await expression found in STMT.
1790 : : NULL_TREE if there are none.
1791 : : So can be used to determine if the statement needs to be processed for
1792 : : awaits. */
1793 : :
1794 : : static tree
1795 : 384744 : co_await_find_in_subtree (tree *stmt, int *, void *d)
1796 : : {
1797 : 384744 : tree **p = (tree **) d;
1798 : 384744 : if (TREE_CODE (*stmt) == CO_AWAIT_EXPR)
1799 : : {
1800 : 3515 : *p = stmt;
1801 : 3515 : return *stmt;
1802 : : }
1803 : : return NULL_TREE;
1804 : : }
1805 : :
1806 : : /* Starting with a statement:
1807 : :
1808 : : stmt => some tree containing one or more await expressions.
1809 : :
1810 : : We replace the statement with:
1811 : : <STATEMENT_LIST> {
1812 : : initialize awaitable
1813 : : if (!ready)
1814 : : {
1815 : : suspension context.
1816 : : }
1817 : : resume:
1818 : : revised statement with one await expression rewritten to its
1819 : : await_resume() return value.
1820 : : }
1821 : :
1822 : : We then recurse into the initializer and the revised statement
1823 : : repeating this replacement until there are no more await expressions
1824 : : in either. */
1825 : :
1826 : : static tree *
1827 : 3515 : expand_one_await_expression (tree *stmt, tree *await_expr, void *d)
1828 : : {
1829 : 3515 : coro_aw_data *data = (coro_aw_data *) d;
1830 : :
1831 : 3515 : tree saved_statement = *stmt;
1832 : 3515 : tree saved_co_await = *await_expr;
1833 : :
1834 : 3515 : tree actor = data->actor_fn;
1835 : 3515 : location_t loc = EXPR_LOCATION (*stmt);
1836 : 3515 : tree var = TREE_OPERAND (saved_co_await, 1); /* frame slot. */
1837 : 3515 : tree expr = TREE_OPERAND (saved_co_await, 2); /* initializer. */
1838 : 3515 : tree awaiter_calls = TREE_OPERAND (saved_co_await, 3);
1839 : :
1840 : 3515 : tree source = TREE_OPERAND (saved_co_await, 4);
1841 : 3515 : bool is_final = (source
1842 : 3515 : && TREE_INT_CST_LOW (source) == (int) FINAL_SUSPEND_POINT);
1843 : 3515 : bool needs_dtor = TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (var));
1844 : 3515 : int resume_point = data->index;
1845 : 3515 : size_t bufsize = sizeof ("destroy.") + 10;
1846 : 3515 : char *buf = (char *) alloca (bufsize);
1847 : 3515 : snprintf (buf, bufsize, "destroy.%d", resume_point);
1848 : 3515 : tree destroy_label = create_named_label_with_ctx (loc, buf, actor);
1849 : 3515 : snprintf (buf, bufsize, "resume.%d", resume_point);
1850 : 3515 : tree resume_label = create_named_label_with_ctx (loc, buf, actor);
1851 : 3515 : tree empty_list = build_empty_stmt (loc);
1852 : :
1853 : 3515 : tree stmt_list = NULL;
1854 : 3515 : tree r;
1855 : 3515 : tree *await_init = NULL;
1856 : :
1857 : 3515 : if (!expr)
1858 : : needs_dtor = false; /* No need, the var's lifetime is managed elsewhere. */
1859 : : else
1860 : : {
1861 : 0 : r = coro_build_cvt_void_expr_stmt (expr, loc);
1862 : 0 : append_to_statement_list_force (r, &stmt_list);
1863 : : /* We have an initializer, which might itself contain await exprs. */
1864 : 0 : await_init = tsi_stmt_ptr (tsi_last (stmt_list));
1865 : : }
1866 : :
1867 : : /* Use the await_ready() call to test if we need to suspend. */
1868 : 3515 : tree ready_cond = TREE_VEC_ELT (awaiter_calls, 0); /* await_ready(). */
1869 : : /* Convert to bool, if necessary. */
1870 : 3515 : if (TREE_CODE (TREE_TYPE (ready_cond)) != BOOLEAN_TYPE)
1871 : 2 : ready_cond = cp_convert (boolean_type_node, ready_cond,
1872 : : tf_warning_or_error);
1873 : : /* Be aggressive in folding here, since there are a significant number of
1874 : : cases where the ready condition is constant. */
1875 : 3515 : ready_cond = invert_truthvalue_loc (loc, ready_cond);
1876 : 3515 : ready_cond
1877 : 3515 : = build1_loc (loc, CLEANUP_POINT_EXPR, boolean_type_node, ready_cond);
1878 : :
1879 : 3515 : tree body_list = NULL;
1880 : 3515 : tree susp_idx = build_int_cst (short_unsigned_type_node, data->index);
1881 : 3515 : r = build2_loc (loc, MODIFY_EXPR, short_unsigned_type_node, data->resume_idx,
1882 : : susp_idx);
1883 : 3515 : r = coro_build_cvt_void_expr_stmt (r, loc);
1884 : 3515 : append_to_statement_list (r, &body_list);
1885 : :
1886 : : /* Find out what we have to do with the awaiter's suspend method.
1887 : : [expr.await]
1888 : : (5.1) If the result of await-ready is false, the coroutine is considered
1889 : : suspended. Then:
1890 : : (5.1.1) If the type of await-suspend is std::coroutine_handle<Z>,
1891 : : await-suspend.resume() is evaluated.
1892 : : (5.1.2) if the type of await-suspend is bool, await-suspend is evaluated,
1893 : : and the coroutine is resumed if the result is false.
1894 : : (5.1.3) Otherwise, await-suspend is evaluated. */
1895 : :
1896 : 3515 : tree suspend = TREE_VEC_ELT (awaiter_calls, 1); /* await_suspend(). */
1897 : 3515 : tree susp_type = TREE_TYPE (suspend);
1898 : :
1899 : 3515 : bool is_cont = false;
1900 : : /* NOTE: final suspend can't resume; the "resume" label in that case
1901 : : corresponds to implicit destruction. */
1902 : 3515 : if (VOID_TYPE_P (susp_type))
1903 : : {
1904 : : /* We just call await_suspend() and hit the yield. */
1905 : 3434 : suspend = coro_build_cvt_void_expr_stmt (suspend, loc);
1906 : 3434 : append_to_statement_list (suspend, &body_list);
1907 : : }
1908 : 81 : else if (TREE_CODE (susp_type) == BOOLEAN_TYPE)
1909 : : {
1910 : : /* Boolean return, continue if the call returns false. */
1911 : 21 : suspend = build1_loc (loc, TRUTH_NOT_EXPR, boolean_type_node, suspend);
1912 : 21 : suspend
1913 : 21 : = build1_loc (loc, CLEANUP_POINT_EXPR, boolean_type_node, suspend);
1914 : 21 : tree go_on = build1_loc (loc, GOTO_EXPR, void_type_node, resume_label);
1915 : 21 : r = build3_loc (loc, COND_EXPR, void_type_node, suspend, go_on,
1916 : : empty_list);
1917 : 21 : append_to_statement_list (r, &body_list);
1918 : : }
1919 : : else
1920 : : {
1921 : 60 : r = suspend;
1922 : 60 : if (!same_type_ignoring_top_level_qualifiers_p (susp_type,
1923 : : void_coro_handle_type))
1924 : 11 : r = build1_loc (loc, VIEW_CONVERT_EXPR, void_coro_handle_type, r);
1925 : 60 : r = cp_build_init_expr (loc, data->conthand, r);
1926 : 60 : r = build1 (CONVERT_EXPR, void_type_node, r);
1927 : 60 : append_to_statement_list (r, &body_list);
1928 : 60 : is_cont = true;
1929 : : }
1930 : :
1931 : 3515 : tree d_l = build_address (destroy_label);
1932 : 3515 : tree r_l = build_address (resume_label);
1933 : 3515 : tree susp = build_address (data->cororet);
1934 : 3515 : tree cont = build_address (data->corocont);
1935 : 5748 : tree final_susp = build_int_cst (integer_type_node, is_final ? 1 : 0);
1936 : :
1937 : 3515 : susp_idx = build_int_cst (integer_type_node, data->index);
1938 : :
1939 : 3515 : tree sw = begin_switch_stmt ();
1940 : 3515 : tree cond = build_decl (loc, VAR_DECL, NULL_TREE, integer_type_node);
1941 : 3515 : DECL_ARTIFICIAL (cond) = 1;
1942 : 3515 : DECL_IGNORED_P (cond) = 1;
1943 : 3515 : layout_decl (cond, 0);
1944 : :
1945 : 3515 : r = build_call_expr_internal_loc (loc, IFN_CO_YIELD, integer_type_node, 5,
1946 : : susp_idx, final_susp, r_l, d_l,
1947 : : data->coro_fp);
1948 : 3515 : r = cp_build_init_expr (cond, r);
1949 : 3515 : finish_switch_cond (r, sw);
1950 : 3515 : finish_case_label (loc, integer_zero_node, NULL_TREE); /* case 0: */
1951 : : /* Implement the suspend, a scope exit without clean ups. */
1952 : 6970 : r = build_call_expr_internal_loc (loc, IFN_CO_SUSPN, void_type_node, 1,
1953 : : is_cont ? cont : susp);
1954 : 3515 : r = coro_build_cvt_void_expr_stmt (r, loc);
1955 : 3515 : add_stmt (r); /* goto ret; */
1956 : 3515 : finish_case_label (loc, integer_one_node, NULL_TREE); /* case 1: */
1957 : 3515 : r = build1_loc (loc, GOTO_EXPR, void_type_node, resume_label);
1958 : 3515 : add_stmt (r); /* goto resume; */
1959 : 3515 : finish_case_label (loc, NULL_TREE, NULL_TREE); /* default:; */
1960 : 3515 : r = build1_loc (loc, GOTO_EXPR, void_type_node, destroy_label);
1961 : 3515 : add_stmt (r); /* goto destroy; */
1962 : :
1963 : : /* part of finish switch. */
1964 : 3515 : SWITCH_STMT_BODY (sw) = pop_stmt_list (SWITCH_STMT_BODY (sw));
1965 : 3515 : pop_switch ();
1966 : 3515 : tree scope = SWITCH_STMT_SCOPE (sw);
1967 : 3515 : SWITCH_STMT_SCOPE (sw) = NULL;
1968 : 3515 : r = do_poplevel (scope);
1969 : 3515 : append_to_statement_list (r, &body_list);
1970 : :
1971 : 3515 : destroy_label = build_stmt (loc, LABEL_EXPR, destroy_label);
1972 : 3515 : append_to_statement_list (destroy_label, &body_list);
1973 : 3515 : if (needs_dtor)
1974 : : {
1975 : 0 : tree dtor = build_cleanup (var);
1976 : 0 : append_to_statement_list (dtor, &body_list);
1977 : : }
1978 : 3515 : r = build1_loc (loc, GOTO_EXPR, void_type_node, data->cleanup);
1979 : 3515 : append_to_statement_list (r, &body_list);
1980 : :
1981 : 3515 : r = build3_loc (loc, COND_EXPR, void_type_node, ready_cond, body_list,
1982 : : empty_list);
1983 : :
1984 : 3515 : append_to_statement_list (r, &stmt_list);
1985 : :
1986 : : /* Resume point. */
1987 : 3515 : resume_label = build_stmt (loc, LABEL_EXPR, resume_label);
1988 : 3515 : append_to_statement_list (resume_label, &stmt_list);
1989 : :
1990 : : /* This will produce the value (if one is provided) from the co_await
1991 : : expression. */
1992 : 3515 : tree resume_call = TREE_VEC_ELT (awaiter_calls, 2); /* await_resume(). */
1993 : 3515 : if (REFERENCE_REF_P (resume_call))
1994 : : /* Sink to await_resume call_expr. */
1995 : 27 : resume_call = TREE_OPERAND (resume_call, 0);
1996 : :
1997 : 3515 : *await_expr = resume_call; /* Replace the co_await expr with its result. */
1998 : 3515 : append_to_statement_list_force (saved_statement, &stmt_list);
1999 : : /* Get a pointer to the revised statement. */
2000 : 3515 : tree *revised = tsi_stmt_ptr (tsi_last (stmt_list));
2001 : 3515 : if (needs_dtor)
2002 : : {
2003 : 0 : tree dtor = build_cleanup (var);
2004 : 0 : append_to_statement_list (dtor, &stmt_list);
2005 : : }
2006 : 3515 : data->index += 2;
2007 : :
2008 : : /* Replace the original statement with the expansion. */
2009 : 3515 : *stmt = stmt_list;
2010 : :
2011 : : /* Now, if the awaitable had an initializer, expand any awaits that might
2012 : : be embedded in it. */
2013 : 3515 : tree *aw_expr_ptr;
2014 : 3515 : if (await_init &&
2015 : 0 : cp_walk_tree (await_init, co_await_find_in_subtree, &aw_expr_ptr, NULL))
2016 : 0 : expand_one_await_expression (await_init, aw_expr_ptr, d);
2017 : :
2018 : : /* Expand any more await expressions in the original statement. */
2019 : 3515 : if (cp_walk_tree (revised, co_await_find_in_subtree, &aw_expr_ptr, NULL))
2020 : 16 : expand_one_await_expression (revised, aw_expr_ptr, d);
2021 : :
2022 : 3515 : return NULL;
2023 : : }
2024 : :
2025 : : /* Check to see if a statement contains at least one await expression, if
2026 : : so, then process that. */
2027 : :
2028 : : static tree
2029 : 43620 : process_one_statement (tree *stmt, void *d)
2030 : : {
2031 : 43620 : tree *aw_expr_ptr;
2032 : 43620 : if (cp_walk_tree (stmt, co_await_find_in_subtree, &aw_expr_ptr, NULL))
2033 : 3499 : expand_one_await_expression (stmt, aw_expr_ptr, d);
2034 : 43620 : return NULL_TREE;
2035 : : }
2036 : :
2037 : : static tree
2038 : 239501 : await_statement_expander (tree *stmt, int *do_subtree, void *d)
2039 : : {
2040 : 239501 : tree res = NULL_TREE;
2041 : :
2042 : : /* Process a statement at a time. */
2043 : 239501 : if (STATEMENT_CLASS_P (*stmt) || TREE_CODE (*stmt) == BIND_EXPR)
2044 : : return NULL_TREE; /* Just process the sub-trees. */
2045 : 170430 : else if (TREE_CODE (*stmt) == STATEMENT_LIST)
2046 : : {
2047 : 106851 : for (tree &s : tsi_range (*stmt))
2048 : : {
2049 : 92789 : res = cp_walk_tree (&s, await_statement_expander,
2050 : : d, NULL);
2051 : 92789 : if (res)
2052 : 0 : return res;
2053 : : }
2054 : 14062 : *do_subtree = 0; /* Done subtrees. */
2055 : : }
2056 : 156368 : else if (EXPR_P (*stmt))
2057 : : {
2058 : 43620 : process_one_statement (stmt, d);
2059 : 43620 : *do_subtree = 0; /* Done subtrees. */
2060 : : }
2061 : :
2062 : : /* Continue statement walk, where required. */
2063 : : return res;
2064 : : }
2065 : :
2066 : : struct await_xform_data
2067 : : {
2068 : : tree actor_fn; /* Decl for context. */
2069 : : tree actor_frame;
2070 : : hash_map<tree, suspend_point_info> *suspend_points;
2071 : : };
2072 : :
2073 : : /* When we built the await expressions, we didn't know the coro frame
2074 : : layout, therefore no idea where to find the promise or where to put
2075 : : the awaitables. Now we know these things, fill them in. */
2076 : :
2077 : : static tree
2078 : 3515 : transform_await_expr (tree await_expr, await_xform_data *xform)
2079 : : {
2080 : 3515 : suspend_point_info *si = xform->suspend_points->get (await_expr);
2081 : 3515 : location_t loc = EXPR_LOCATION (await_expr);
2082 : 3515 : if (!si)
2083 : : {
2084 : 0 : error_at (loc, "no suspend point info for %qD", await_expr);
2085 : 0 : return error_mark_node;
2086 : : }
2087 : :
2088 : : /* So, on entry, we have:
2089 : : in : CO_AWAIT_EXPR (a, e_proxy, o, awr_call_vector, mode)
2090 : : We no longer need a [it had diagnostic value, maybe?]
2091 : : We need to replace the e_proxy in the awr_call. */
2092 : :
2093 : : /* If we have a frame var for the awaitable, get a reference to it. */
2094 : 3515 : proxy_replace data;
2095 : 3515 : if (si->await_field_id)
2096 : : {
2097 : 0 : tree as
2098 : 0 : = coro_build_frame_access_expr (xform->actor_frame, si->await_field_id,
2099 : : true, tf_warning_or_error);
2100 : : /* Replace references to the instance proxy with the frame entry now
2101 : : computed. */
2102 : 0 : data.from = TREE_OPERAND (await_expr, 1);
2103 : 0 : data.to = as;
2104 : 0 : cp_walk_tree (&await_expr, replace_proxy, &data, NULL);
2105 : :
2106 : : /* .. and replace. */
2107 : 0 : TREE_OPERAND (await_expr, 1) = as;
2108 : : }
2109 : :
2110 : 3515 : return await_expr;
2111 : : }
2112 : :
2113 : : /* A wrapper for the transform_await_expr function so that it can be a
2114 : : callback from cp_walk_tree. */
2115 : :
2116 : : static tree
2117 : 274701 : transform_await_wrapper (tree *stmt, int *do_subtree, void *d)
2118 : : {
2119 : : /* Set actor function as new DECL_CONTEXT of label_decl. */
2120 : 274701 : struct await_xform_data *xform = (struct await_xform_data *) d;
2121 : 274701 : if (TREE_CODE (*stmt) == LABEL_DECL
2122 : 274701 : && DECL_CONTEXT (*stmt) != xform->actor_fn)
2123 : 1346 : DECL_CONTEXT (*stmt) = xform->actor_fn;
2124 : :
2125 : : /* We should have already lowered co_yields to their co_await. */
2126 : 274701 : gcc_checking_assert (TREE_CODE (*stmt) != CO_YIELD_EXPR);
2127 : 274701 : if (TREE_CODE (*stmt) != CO_AWAIT_EXPR)
2128 : : return NULL_TREE;
2129 : :
2130 : 3515 : tree await_expr = *stmt;
2131 : 3515 : *stmt = transform_await_expr (await_expr, xform);
2132 : 3515 : if (*stmt == error_mark_node)
2133 : 0 : *do_subtree = 0;
2134 : : return NULL_TREE;
2135 : : }
2136 : :
2137 : : /* For figuring out what local variable usage we have. */
2138 : : struct local_vars_transform
2139 : : {
2140 : : tree context;
2141 : : tree actor_frame;
2142 : : tree coro_frame_type;
2143 : : location_t loc;
2144 : : hash_map<tree, local_var_info> *local_var_uses;
2145 : : };
2146 : :
2147 : : static tree
2148 : 425266 : transform_local_var_uses (tree *stmt, int *do_subtree, void *d)
2149 : : {
2150 : 425266 : local_vars_transform *lvd = (local_vars_transform *) d;
2151 : :
2152 : : /* For each var in this bind expr (that has a frame id, which means it was
2153 : : accessed), build a frame reference and add it as the DECL_VALUE_EXPR. */
2154 : :
2155 : 425266 : if (TREE_CODE (*stmt) == BIND_EXPR)
2156 : : {
2157 : 6313 : tree lvar;
2158 : 20841 : for (lvar = BIND_EXPR_VARS (*stmt); lvar != NULL;
2159 : 14528 : lvar = DECL_CHAIN (lvar))
2160 : : {
2161 : 14528 : bool existed;
2162 : 14528 : local_var_info &local_var
2163 : 14528 : = lvd->local_var_uses->get_or_insert (lvar, &existed);
2164 : 14528 : gcc_checking_assert (existed);
2165 : :
2166 : : /* Re-write the variable's context to be in the actor func. */
2167 : 14528 : DECL_CONTEXT (lvar) = lvd->context;
2168 : :
2169 : : /* For capture proxies, this could include the decl value expr. */
2170 : 14528 : if (local_var.is_lambda_capture || local_var.has_value_expr_p)
2171 : 143 : continue; /* No frame entry for this. */
2172 : :
2173 : : /* TODO: implement selective generation of fields when vars are
2174 : : known not-used. */
2175 : 14410 : if (local_var.field_id == NULL_TREE)
2176 : 25 : continue; /* Wasn't used. */
2177 : 14385 : tree fld_idx
2178 : 14385 : = coro_build_frame_access_expr (lvd->actor_frame,
2179 : : local_var.field_id, true,
2180 : : tf_warning_or_error);
2181 : 14385 : local_var.field_idx = fld_idx;
2182 : 14385 : SET_DECL_VALUE_EXPR (lvar, fld_idx);
2183 : 14385 : DECL_HAS_VALUE_EXPR_P (lvar) = true;
2184 : : }
2185 : 6313 : cp_walk_tree (&BIND_EXPR_BODY (*stmt), transform_local_var_uses, d, NULL);
2186 : 6313 : *do_subtree = 0; /* We've done the body already. */
2187 : 6313 : return NULL_TREE;
2188 : : }
2189 : : return NULL_TREE;
2190 : : }
2191 : :
2192 : : /* A helper to build the frame DTOR.
2193 : : [dcl.fct.def.coroutine] / 12
2194 : : The deallocation function’s name is looked up in the scope of the promise
2195 : : type. If this lookup fails, the deallocation function’s name is looked up
2196 : : in the global scope. If deallocation function lookup finds both a usual
2197 : : deallocation function with only a pointer parameter and a usual
2198 : : deallocation function with both a pointer parameter and a size parameter,
2199 : : then the selected deallocation function shall be the one with two
2200 : : parameters. Otherwise, the selected deallocation function shall be the
2201 : : function with one parameter. If no usual deallocation function is found
2202 : : the program is ill-formed. The selected deallocation function shall be
2203 : : called with the address of the block of storage to be reclaimed as its
2204 : : first argument. If a deallocation function with a parameter of type
2205 : : std::size_t is used, the size of the block is passed as the corresponding
2206 : : argument. */
2207 : :
2208 : : static tree
2209 : : build_coroutine_frame_delete_expr (tree, tree, tree, location_t);
2210 : :
2211 : : /* The actor transform. */
2212 : :
2213 : : static void
2214 : 1292 : build_actor_fn (location_t loc, tree coro_frame_type, tree actor, tree fnbody,
2215 : : tree orig, hash_map<tree, local_var_info> *local_var_uses,
2216 : : hash_map<tree, suspend_point_info> *suspend_points,
2217 : : vec<tree> *param_dtor_list,
2218 : : tree resume_idx_var, unsigned body_count, tree frame_size,
2219 : : bool inline_p)
2220 : : {
2221 : 1292 : verify_stmt_tree (fnbody);
2222 : : /* Some things we inherit from the original function. */
2223 : 1292 : tree promise_type = get_coroutine_promise_type (orig);
2224 : 1292 : tree promise_proxy = get_coroutine_promise_proxy (orig);
2225 : :
2226 : : /* One param, the coro frame pointer. */
2227 : 1292 : tree actor_fp = DECL_ARGUMENTS (actor);
2228 : :
2229 : 1292 : bool spf = start_preparsed_function (actor, NULL_TREE, SF_PRE_PARSED);
2230 : 1292 : gcc_checking_assert (spf);
2231 : 1292 : gcc_checking_assert (cfun && current_function_decl && TREE_STATIC (actor));
2232 : 1292 : tree stmt = begin_function_body ();
2233 : :
2234 : 1292 : tree actor_bind = build3 (BIND_EXPR, void_type_node, NULL, NULL, NULL);
2235 : 1292 : tree top_block = make_node (BLOCK);
2236 : 1292 : BIND_EXPR_BLOCK (actor_bind) = top_block;
2237 : :
2238 : 1292 : tree continuation = coro_build_artificial_var (loc, coro_actor_continue_id,
2239 : : void_coro_handle_type, actor,
2240 : : NULL_TREE);
2241 : :
2242 : 1292 : BIND_EXPR_VARS (actor_bind) = continuation;
2243 : 1292 : BLOCK_VARS (top_block) = BIND_EXPR_VARS (actor_bind) ;
2244 : :
2245 : : /* Link in the block associated with the outer scope of the re-written
2246 : : function body. */
2247 : 1292 : tree first = expr_first (fnbody);
2248 : 1292 : gcc_checking_assert (first && TREE_CODE (first) == BIND_EXPR);
2249 : 1292 : tree block = BIND_EXPR_BLOCK (first);
2250 : 1292 : gcc_checking_assert (BLOCK_SUPERCONTEXT (block) == NULL_TREE);
2251 : 1292 : gcc_checking_assert (BLOCK_CHAIN (block) == NULL_TREE);
2252 : 1292 : BLOCK_SUPERCONTEXT (block) = top_block;
2253 : 1292 : BLOCK_SUBBLOCKS (top_block) = block;
2254 : :
2255 : 1292 : add_stmt (actor_bind);
2256 : 1292 : tree actor_body = push_stmt_list ();
2257 : :
2258 : : /* The entry point for the actor code from the ramp. */
2259 : 1292 : tree actor_begin_label
2260 : 1292 : = create_named_label_with_ctx (loc, "actor.begin", actor);
2261 : 1292 : tree actor_frame = build1_loc (loc, INDIRECT_REF, coro_frame_type, actor_fp);
2262 : :
2263 : : /* Declare the continuation handle. */
2264 : 1292 : add_decl_expr (continuation);
2265 : :
2266 : : /* Re-write local vars, similarly. */
2267 : 1292 : local_vars_transform xform_vars_data
2268 : 1292 : = {actor, actor_frame, coro_frame_type, loc, local_var_uses};
2269 : 1292 : cp_walk_tree (&fnbody, transform_local_var_uses, &xform_vars_data, NULL);
2270 : 1292 : tree rat = coro_build_frame_access_expr (actor_frame, coro_resume_index_id,
2271 : : false, tf_warning_or_error);
2272 : 1292 : tree ret_label
2273 : 1292 : = create_named_label_with_ctx (loc, "actor.suspend.ret", actor);
2274 : :
2275 : 1292 : tree continue_label
2276 : 1292 : = create_named_label_with_ctx (loc, "actor.continue.ret", actor);
2277 : :
2278 : 1292 : tree lsb_if = begin_if_stmt ();
2279 : 1292 : tree chkb0 = build2 (BIT_AND_EXPR, short_unsigned_type_node, rat,
2280 : 1292 : build_int_cst (short_unsigned_type_node, 1));
2281 : 1292 : chkb0 = build2 (NE_EXPR, short_unsigned_type_node, chkb0,
2282 : 1292 : build_int_cst (short_unsigned_type_node, 0));
2283 : 1292 : finish_if_stmt_cond (chkb0, lsb_if);
2284 : :
2285 : 1292 : tree destroy_dispatcher = begin_switch_stmt ();
2286 : 1292 : finish_switch_cond (rat, destroy_dispatcher);
2287 : 1292 : tree ddeflab = finish_case_label (loc, NULL_TREE, NULL_TREE);
2288 : 1292 : tree b = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_TRAP), 0);
2289 : 1292 : b = coro_build_cvt_void_expr_stmt (b, loc);
2290 : 1292 : add_stmt (b);
2291 : :
2292 : : /* The destroy point numbered #1 is special, in that it is reached from a
2293 : : coroutine that is suspended after re-throwing from unhandled_exception().
2294 : : This label just invokes the cleanup of promise, param copies and the
2295 : : frame itself. */
2296 : 1292 : tree del_promise_label
2297 : 1292 : = create_named_label_with_ctx (loc, "coro.delete.promise", actor);
2298 : 1292 : finish_case_label (loc, build_int_cst (short_unsigned_type_node, 1),
2299 : : NULL_TREE);
2300 : 1292 : add_stmt (build_stmt (loc, GOTO_EXPR, del_promise_label));
2301 : :
2302 : 1292 : short unsigned lab_num = 3;
2303 : 4807 : for (unsigned destr_pt = 0; destr_pt < body_count; destr_pt++)
2304 : : {
2305 : 3515 : tree l_num = build_int_cst (short_unsigned_type_node, lab_num);
2306 : 3515 : finish_case_label (loc, l_num, NULL_TREE);
2307 : 3515 : b = build_call_expr_internal_loc (loc, IFN_CO_ACTOR, void_type_node, 1,
2308 : : l_num);
2309 : 3515 : b = coro_build_cvt_void_expr_stmt (b, loc);
2310 : 3515 : add_stmt (b);
2311 : 3515 : b = build1 (GOTO_EXPR, void_type_node, CASE_LABEL (ddeflab));
2312 : 3515 : add_stmt (b);
2313 : 3515 : lab_num += 2;
2314 : : }
2315 : :
2316 : : /* Insert the prototype dispatcher. */
2317 : 1292 : finish_switch_stmt (destroy_dispatcher);
2318 : :
2319 : 1292 : finish_then_clause (lsb_if);
2320 : 1292 : begin_else_clause (lsb_if);
2321 : :
2322 : 1292 : tree dispatcher = begin_switch_stmt ();
2323 : 1292 : finish_switch_cond (rat, dispatcher);
2324 : 1292 : finish_case_label (loc, build_int_cst (short_unsigned_type_node, 0),
2325 : : NULL_TREE);
2326 : 1292 : b = build1 (GOTO_EXPR, void_type_node, actor_begin_label);
2327 : 1292 : add_stmt (b);
2328 : :
2329 : 1292 : tree rdeflab = finish_case_label (loc, NULL_TREE, NULL_TREE);
2330 : 1292 : b = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_TRAP), 0);
2331 : 1292 : b = coro_build_cvt_void_expr_stmt (b, loc);
2332 : 1292 : add_stmt (b);
2333 : :
2334 : 1292 : lab_num = 2;
2335 : : /* The final resume should be made to hit the default (trap, UB) entry
2336 : : although it will be unreachable via the normal entry point, since that
2337 : : is set to NULL on reaching final suspend. */
2338 : 4807 : for (unsigned resu_pt = 0; resu_pt < body_count; resu_pt++)
2339 : : {
2340 : 3515 : tree l_num = build_int_cst (short_unsigned_type_node, lab_num);
2341 : 3515 : finish_case_label (loc, l_num, NULL_TREE);
2342 : 3515 : b = build_call_expr_internal_loc (loc, IFN_CO_ACTOR, void_type_node, 1,
2343 : : l_num);
2344 : 3515 : b = coro_build_cvt_void_expr_stmt (b, loc);
2345 : 3515 : add_stmt (b);
2346 : 3515 : b = build1 (GOTO_EXPR, void_type_node, CASE_LABEL (rdeflab));
2347 : 3515 : add_stmt (b);
2348 : 3515 : lab_num += 2;
2349 : : }
2350 : :
2351 : : /* Insert the prototype dispatcher. */
2352 : 1292 : finish_switch_stmt (dispatcher);
2353 : 1292 : finish_else_clause (lsb_if);
2354 : :
2355 : 1292 : finish_if_stmt (lsb_if);
2356 : :
2357 : 1292 : tree r = build_stmt (loc, LABEL_EXPR, actor_begin_label);
2358 : 1292 : add_stmt (r);
2359 : :
2360 : : /* actor's coroutine 'self handle'. */
2361 : 1292 : tree ash = coro_build_frame_access_expr (actor_frame, coro_self_handle_id,
2362 : : false, tf_warning_or_error);
2363 : : /* So construct the self-handle from the frame address. */
2364 : 1292 : tree hfa_m = get_coroutine_from_address (orig);
2365 : : /* Should have been set earlier by coro_promise_type_found_p. */
2366 : 1292 : gcc_assert (hfa_m);
2367 : :
2368 : 1292 : r = build1 (CONVERT_EXPR, build_pointer_type (void_type_node), actor_fp);
2369 : 1292 : vec<tree, va_gc> *args = make_tree_vector_single (r);
2370 : 1292 : tree hfa = build_new_method_call (ash, hfa_m, &args, NULL_TREE, LOOKUP_NORMAL,
2371 : : NULL, tf_warning_or_error);
2372 : 1292 : r = cp_build_init_expr (ash, hfa);
2373 : 1292 : r = coro_build_cvt_void_expr_stmt (r, loc);
2374 : 1292 : add_stmt (r);
2375 : 1292 : release_tree_vector (args);
2376 : :
2377 : : /* Now we know the real promise, and enough about the frame layout to
2378 : : decide where to put things. */
2379 : :
2380 : 1292 : await_xform_data xform = {actor, actor_frame, suspend_points};
2381 : :
2382 : : /* Transform the await expressions in the function body. Only do each
2383 : : await tree once! */
2384 : 1292 : hash_set<tree> pset;
2385 : 1292 : cp_walk_tree (&fnbody, transform_await_wrapper, &xform, &pset);
2386 : :
2387 : : /* Add in our function body with the co_returns rewritten to final form. */
2388 : 1292 : add_stmt (fnbody);
2389 : :
2390 : : /* now do the tail of the function. */
2391 : 1292 : r = build_stmt (loc, LABEL_EXPR, del_promise_label);
2392 : 1292 : add_stmt (r);
2393 : :
2394 : : /* Destructors for the things we built explicitly. */
2395 : 1292 : if (tree c = cxx_maybe_build_cleanup (promise_proxy, tf_warning_or_error))
2396 : 952 : add_stmt (c);
2397 : :
2398 : 1292 : tree del_frame_label
2399 : 1292 : = create_named_label_with_ctx (loc, "coro.delete.frame", actor);
2400 : 1292 : r = build_stmt (loc, LABEL_EXPR, del_frame_label);
2401 : 1292 : add_stmt (r);
2402 : :
2403 : : /* Here deallocate the frame (if we allocated it), which we will have at
2404 : : present. */
2405 : 1292 : tree fnf2_x
2406 : 1292 : = coro_build_frame_access_expr (actor_frame, coro_frame_needs_free_id,
2407 : : false, tf_warning_or_error);
2408 : :
2409 : 1292 : tree need_free_if = begin_if_stmt ();
2410 : 1292 : fnf2_x = build1 (CONVERT_EXPR, integer_type_node, fnf2_x);
2411 : 1292 : tree cmp = build2 (NE_EXPR, integer_type_node, fnf2_x, integer_zero_node);
2412 : 1292 : finish_if_stmt_cond (cmp, need_free_if);
2413 : 2665 : while (!param_dtor_list->is_empty ())
2414 : : {
2415 : 81 : tree parm_id = param_dtor_list->pop ();
2416 : 81 : tree a = coro_build_frame_access_expr (actor_frame, parm_id, false,
2417 : : tf_warning_or_error);
2418 : 81 : if (tree dtor = cxx_maybe_build_cleanup (a, tf_warning_or_error))
2419 : 81 : add_stmt (dtor);
2420 : : }
2421 : :
2422 : : /* Build the frame DTOR. */
2423 : 1292 : tree del_coro_fr
2424 : 1292 : = build_coroutine_frame_delete_expr (actor_fp, frame_size,
2425 : : promise_type, loc);
2426 : 1292 : finish_expr_stmt (del_coro_fr);
2427 : 1292 : finish_then_clause (need_free_if);
2428 : 1292 : tree scope = IF_SCOPE (need_free_if);
2429 : 1292 : IF_SCOPE (need_free_if) = NULL;
2430 : 1292 : r = do_poplevel (scope);
2431 : 1292 : add_stmt (r);
2432 : :
2433 : : /* done. */
2434 : 1292 : r = build_stmt (loc, RETURN_EXPR, NULL);
2435 : 1292 : suppress_warning (r); /* We don't want a warning about this. */
2436 : 1292 : r = maybe_cleanup_point_expr_void (r);
2437 : 1292 : add_stmt (r);
2438 : :
2439 : : /* This is the suspend return point. */
2440 : 1292 : r = build_stmt (loc, LABEL_EXPR, ret_label);
2441 : 1292 : add_stmt (r);
2442 : :
2443 : 1292 : r = build_stmt (loc, RETURN_EXPR, NULL);
2444 : 1292 : suppress_warning (r); /* We don't want a warning about this. */
2445 : 1292 : r = maybe_cleanup_point_expr_void (r);
2446 : 1292 : add_stmt (r);
2447 : :
2448 : : /* This is the 'continuation' return point. For such a case we have a coro
2449 : : handle (from the await_suspend() call) and we want handle.resume() to
2450 : : execute as a tailcall allowing arbitrary chaining of coroutines. */
2451 : 1292 : r = build_stmt (loc, LABEL_EXPR, continue_label);
2452 : 1292 : add_stmt (r);
2453 : :
2454 : : /* Should have been set earlier by the coro_initialized code. */
2455 : 1292 : gcc_assert (void_coro_handle_address);
2456 : :
2457 : : /* We want to force a tail-call even for O0/1, so this expands the resume
2458 : : call into its underlying implementation. */
2459 : 1292 : tree addr = build_new_method_call (continuation, void_coro_handle_address,
2460 : : NULL, NULL_TREE, LOOKUP_NORMAL, NULL,
2461 : : tf_warning_or_error);
2462 : 1292 : tree resume = build_call_expr_loc
2463 : 1292 : (loc, builtin_decl_explicit (BUILT_IN_CORO_RESUME), 1, addr);
2464 : :
2465 : : /* In order to support an arbitrary number of coroutine continuations,
2466 : : we must tail call them. However, some targets do not support indirect
2467 : : tail calls to arbitrary callees. See PR94359. */
2468 : 1292 : CALL_EXPR_TAILCALL (resume) = true;
2469 : 1292 : resume = coro_build_cvt_void_expr_stmt (resume, loc);
2470 : 1292 : add_stmt (resume);
2471 : :
2472 : 1292 : r = build_stmt (loc, RETURN_EXPR, NULL);
2473 : 1292 : gcc_checking_assert (maybe_cleanup_point_expr_void (r) == r);
2474 : 1292 : add_stmt (r);
2475 : :
2476 : : /* We've now rewritten the tree and added the initial and final
2477 : : co_awaits. Now pass over the tree and expand the co_awaits. */
2478 : :
2479 : 1292 : coro_aw_data data = {actor, actor_fp, resume_idx_var, NULL_TREE,
2480 : : ash, del_promise_label, ret_label,
2481 : 1292 : continue_label, continuation, 2};
2482 : 1292 : cp_walk_tree (&actor_body, await_statement_expander, &data, NULL);
2483 : :
2484 : 1292 : BIND_EXPR_BODY (actor_bind) = pop_stmt_list (actor_body);
2485 : 1292 : TREE_SIDE_EFFECTS (actor_bind) = true;
2486 : :
2487 : 1292 : cfun->coroutine_component = 1;
2488 : 1292 : finish_function_body (stmt);
2489 : 1292 : finish_function (inline_p);
2490 : 1292 : }
2491 : :
2492 : : /* The prototype 'destroy' function :
2493 : : frame->__Coro_resume_index |= 1;
2494 : : actor (frame); */
2495 : :
2496 : : static void
2497 : 1292 : build_destroy_fn (location_t loc, tree coro_frame_type, tree destroy,
2498 : : tree actor, bool inline_p)
2499 : : {
2500 : : /* One param, the coro frame pointer. */
2501 : 1292 : tree destr_fp = DECL_ARGUMENTS (destroy);
2502 : 1292 : gcc_checking_assert (POINTER_TYPE_P (TREE_TYPE (destr_fp))
2503 : : && same_type_p (coro_frame_type,
2504 : : TREE_TYPE (TREE_TYPE (destr_fp))));
2505 : :
2506 : 1292 : bool spf = start_preparsed_function (destroy, NULL_TREE, SF_PRE_PARSED);
2507 : 1292 : gcc_checking_assert (spf);
2508 : 1292 : tree dstr_stmt = begin_function_body ();
2509 : :
2510 : 1292 : tree destr_frame
2511 : 1292 : = cp_build_indirect_ref (loc, destr_fp, RO_UNARY_STAR,
2512 : : tf_warning_or_error);
2513 : :
2514 : 1292 : tree rat = coro_build_frame_access_expr (destr_frame, coro_resume_index_id,
2515 : : false, tf_warning_or_error);
2516 : :
2517 : : /* _resume_at |= 1 */
2518 : 1292 : tree dstr_idx
2519 : 1292 : = build2_loc (loc, BIT_IOR_EXPR, short_unsigned_type_node, rat,
2520 : 1292 : build_int_cst (short_unsigned_type_node, 1));
2521 : 1292 : tree r = cp_build_modify_expr (loc, rat, NOP_EXPR, dstr_idx,
2522 : : tf_warning_or_error);
2523 : 1292 : finish_expr_stmt (r);
2524 : :
2525 : : /* So .. call the actor .. */
2526 : 1292 : finish_expr_stmt (build_call_expr_loc (loc, actor, 1, destr_fp));
2527 : :
2528 : : /* done. */
2529 : 1292 : finish_return_stmt (NULL_TREE);
2530 : :
2531 : 1292 : gcc_checking_assert (cfun && current_function_decl);
2532 : 1292 : cfun->coroutine_component = 1;
2533 : 1292 : finish_function_body (dstr_stmt);
2534 : 1292 : finish_function (inline_p);
2535 : 1292 : }
2536 : :
2537 : : /* Helper that returns an identifier for an appended extension to the
2538 : : current un-mangled function name. */
2539 : :
2540 : : static tree
2541 : 1323 : get_fn_local_identifier (tree orig, const char *append)
2542 : : {
2543 : : /* Figure out the bits we need to generate names for the outlined things
2544 : : For consistency, this needs to behave the same way as
2545 : : ASM_FORMAT_PRIVATE_NAME does. */
2546 : 1323 : tree nm = DECL_NAME (orig);
2547 : 1323 : const char *sep, *pfx = "";
2548 : : #ifndef NO_DOT_IN_LABEL
2549 : 1323 : sep = ".";
2550 : : #else
2551 : : #ifndef NO_DOLLAR_IN_LABEL
2552 : : sep = "$";
2553 : : #else
2554 : : sep = "_";
2555 : : pfx = "__";
2556 : : #endif
2557 : : #endif
2558 : :
2559 : 1323 : char *an;
2560 : 1323 : if (DECL_ASSEMBLER_NAME (orig))
2561 : 1323 : an = ACONCAT ((IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (orig)), sep, append,
2562 : : (char *) 0));
2563 : 0 : else if (DECL_USE_TEMPLATE (orig) && DECL_TEMPLATE_INFO (orig)
2564 : 0 : && DECL_TI_ARGS (orig))
2565 : : {
2566 : 0 : tree tpl_args = DECL_TI_ARGS (orig);
2567 : 0 : an = ACONCAT ((pfx, IDENTIFIER_POINTER (nm), (char *) 0));
2568 : 0 : for (int i = 0; i < TREE_VEC_LENGTH (tpl_args); ++i)
2569 : : {
2570 : 0 : tree typ = DECL_NAME (TYPE_NAME (TREE_VEC_ELT (tpl_args, i)));
2571 : 0 : an = ACONCAT ((an, sep, IDENTIFIER_POINTER (typ), (char *) 0));
2572 : : }
2573 : 0 : an = ACONCAT ((an, sep, append, (char *) 0));
2574 : : }
2575 : : else
2576 : 0 : an = ACONCAT ((pfx, IDENTIFIER_POINTER (nm), sep, append, (char *) 0));
2577 : :
2578 : 1323 : return get_identifier (an);
2579 : : }
2580 : :
2581 : : /* Build an initial or final await initialized from the promise
2582 : : initial_suspend or final_suspend expression. */
2583 : :
2584 : : static tree
2585 : 2604 : build_init_or_final_await (location_t loc, bool is_final)
2586 : : {
2587 : 2604 : tree suspend_alt = is_final ? coro_final_suspend_identifier
2588 : : : coro_initial_suspend_identifier;
2589 : :
2590 : 2604 : tree setup_call
2591 : 2604 : = coro_build_promise_expression (current_function_decl, NULL, suspend_alt,
2592 : : loc, NULL, /*musthave=*/true);
2593 : :
2594 : : /* Check for noexcept on the final_suspend call. */
2595 : 2590 : if (flag_exceptions && is_final && setup_call != error_mark_node
2596 : 3898 : && coro_diagnose_throwing_final_aw_expr (setup_call))
2597 : 1 : return error_mark_node;
2598 : :
2599 : : /* So build the co_await for this */
2600 : : /* For initial/final suspends the call is "a" per [expr.await] 3.2. */
2601 : 3905 : return build_co_await (loc, setup_call, (is_final ? FINAL_SUSPEND_POINT
2602 : 2603 : : INITIAL_SUSPEND_POINT));
2603 : : }
2604 : :
2605 : : /* Callback to record the essential data for each await point found in the
2606 : : function. */
2607 : :
2608 : : static bool
2609 : 3535 : register_await_info (tree await_expr, tree aw_type, tree aw_nam,
2610 : : hash_map<tree, suspend_point_info> *suspend_points)
2611 : : {
2612 : 3535 : bool seen;
2613 : 3535 : suspend_point_info &s
2614 : 3535 : = suspend_points->get_or_insert (await_expr, &seen);
2615 : 3535 : if (seen)
2616 : : {
2617 : 0 : warning_at (EXPR_LOCATION (await_expr), 0, "duplicate info for %qE",
2618 : : await_expr);
2619 : 0 : return false;
2620 : : }
2621 : 3535 : s.awaitable_type = aw_type;
2622 : 3535 : s.await_field_id = aw_nam;
2623 : 3535 : return true;
2624 : : }
2625 : :
2626 : : /* If this is an await expression, then count it (both uniquely within the
2627 : : function and locally within a single statement). */
2628 : :
2629 : : static tree
2630 : 177366 : register_awaits (tree *stmt, int *, void *d)
2631 : : {
2632 : 177366 : tree aw_expr = *stmt;
2633 : :
2634 : : /* We should have already lowered co_yields to their co_await. */
2635 : 177366 : gcc_checking_assert (TREE_CODE (aw_expr) != CO_YIELD_EXPR);
2636 : :
2637 : 177366 : if (TREE_CODE (aw_expr) != CO_AWAIT_EXPR)
2638 : : return NULL_TREE;
2639 : :
2640 : : /* Count how many awaits the current expression contains. */
2641 : 3535 : susp_frame_data *data = (susp_frame_data *) d;
2642 : 3535 : data->saw_awaits++;
2643 : : /* Each await suspend context is unique, this is a function-wide value. */
2644 : 3535 : data->await_number++;
2645 : :
2646 : : /* Awaitables should either be user-locals or promoted to coroutine frame
2647 : : entries at this point, and their initializers should have been broken
2648 : : out. */
2649 : 3535 : tree aw = TREE_OPERAND (aw_expr, 1);
2650 : 3535 : gcc_checking_assert (!TREE_OPERAND (aw_expr, 2));
2651 : :
2652 : 3535 : tree aw_field_type = TREE_TYPE (aw);
2653 : 3535 : tree aw_field_nam = NULL_TREE;
2654 : 3535 : register_await_info (aw_expr, aw_field_type, aw_field_nam, data->suspend_points);
2655 : :
2656 : : /* Rewrite target expressions on the await_suspend () to remove extraneous
2657 : : cleanups for the awaitables, which are now promoted to frame vars and
2658 : : managed via that. */
2659 : 3535 : tree v = TREE_OPERAND (aw_expr, 3);
2660 : 3535 : tree o = TREE_VEC_ELT (v, 1);
2661 : 3535 : if (TREE_CODE (o) == TARGET_EXPR)
2662 : 62 : TREE_VEC_ELT (v, 1) = get_target_expr (TREE_OPERAND (o, 1));
2663 : : return NULL_TREE;
2664 : : }
2665 : :
2666 : : /* There are cases where any await expression is relevant. */
2667 : : static tree
2668 : 380304 : find_any_await (tree *stmt, int *dosub, void *d)
2669 : : {
2670 : 380304 : if (TREE_CODE (*stmt) == CO_AWAIT_EXPR)
2671 : : {
2672 : 3600 : *dosub = 0; /* We don't need to consider this any further. */
2673 : 3600 : tree **p = (tree **) d;
2674 : 3600 : *p = stmt;
2675 : 3600 : return *stmt;
2676 : : }
2677 : : return NULL_TREE;
2678 : : }
2679 : :
2680 : : static bool
2681 : 62473 : tmp_target_expr_p (tree t)
2682 : : {
2683 : 62473 : if (TREE_CODE (t) != TARGET_EXPR)
2684 : : return false;
2685 : 4185 : tree v = TREE_OPERAND (t, 0);
2686 : 4185 : if (!DECL_ARTIFICIAL (v))
2687 : : return false;
2688 : 4185 : if (DECL_NAME (v))
2689 : 181 : return false;
2690 : : return true;
2691 : : }
2692 : :
2693 : : /* Structure to record sub-expressions that need to be handled by the
2694 : : statement flattener. */
2695 : :
2696 : : struct coro_interesting_subtree
2697 : : {
2698 : : tree* entry;
2699 : : hash_set<tree> *temps_used;
2700 : : };
2701 : :
2702 : : /* tree-walk callback that returns the first encountered sub-expression of
2703 : : a kind that needs to be handled specifically by the statement flattener. */
2704 : :
2705 : : static tree
2706 : 69478 : find_interesting_subtree (tree *expr_p, int *dosub, void *d)
2707 : : {
2708 : 69478 : tree expr = *expr_p;
2709 : 69478 : coro_interesting_subtree *p = (coro_interesting_subtree *)d;
2710 : 69478 : if (TREE_CODE (expr) == CO_AWAIT_EXPR)
2711 : : {
2712 : 7005 : *dosub = 0; /* We don't need to consider this any further. */
2713 : 7005 : if (TREE_OPERAND (expr, 2))
2714 : : {
2715 : 3454 : p->entry = expr_p;
2716 : 3454 : return expr;
2717 : : }
2718 : : }
2719 : 62473 : else if (tmp_target_expr_p (expr)
2720 : 4004 : && !TARGET_EXPR_ELIDING_P (expr)
2721 : 62722 : && !p->temps_used->contains (expr))
2722 : : {
2723 : 232 : p->entry = expr_p;
2724 : 232 : return expr;
2725 : : }
2726 : :
2727 : : return NULL_TREE;
2728 : : }
2729 : :
2730 : : /* Node for a doubly-linked list of promoted variables and their
2731 : : initializers. When the initializer is a conditional expression
2732 : : the 'then' and 'else' clauses are represented by a linked list
2733 : : attached to then_cl and else_cl respectively. */
2734 : :
2735 : : struct var_nest_node
2736 : : {
2737 : : var_nest_node () = default;
2738 : 7200 : var_nest_node (tree v, tree i, var_nest_node *p, var_nest_node *n)
2739 : 7200 : : var(v), init(i), prev(p), next(n), then_cl (NULL), else_cl (NULL)
2740 : : {
2741 : 7200 : if (p)
2742 : 20 : p->next = this;
2743 : 20 : if (n)
2744 : 3706 : n->prev = this;
2745 : : }
2746 : : tree var;
2747 : : tree init;
2748 : : var_nest_node *prev;
2749 : : var_nest_node *next;
2750 : : var_nest_node *then_cl;
2751 : : var_nest_node *else_cl;
2752 : : };
2753 : :
2754 : : /* This is called for single statements from the co-await statement walker.
2755 : : It checks to see if the statement contains any initializers for awaitables
2756 : : and if any of these capture items by reference. */
2757 : :
2758 : : static void
2759 : 10886 : flatten_await_stmt (var_nest_node *n, hash_set<tree> *promoted,
2760 : : hash_set<tree> *temps_used, tree *replace_in)
2761 : : {
2762 : 10993 : bool init_expr = false;
2763 : 10993 : switch (TREE_CODE (n->init))
2764 : : {
2765 : : default: break;
2766 : : /* Compound expressions must be flattened specifically. */
2767 : 5 : case COMPOUND_EXPR:
2768 : 5 : {
2769 : 5 : tree first = TREE_OPERAND (n->init, 0);
2770 : 5 : n->init = TREE_OPERAND (n->init, 1);
2771 : 5 : var_nest_node *ins
2772 : 5 : = new var_nest_node(NULL_TREE, first, n->prev, n);
2773 : : /* The compiler (but not the user) can generate temporaries with
2774 : : uses in the second arm of a compound expr. */
2775 : 5 : flatten_await_stmt (ins, promoted, temps_used, &n->init);
2776 : 5 : flatten_await_stmt (n, promoted, temps_used, NULL);
2777 : : /* The two arms have been processed separately. */
2778 : 10891 : return;
2779 : : }
2780 : 4368 : break;
2781 : : /* Handle conditional expressions. */
2782 : 4368 : case INIT_EXPR:
2783 : 4368 : init_expr = true;
2784 : : /* FALLTHROUGH */
2785 : 4774 : case MODIFY_EXPR:
2786 : 4774 : {
2787 : 4774 : tree old_expr = TREE_OPERAND (n->init, 1);
2788 : 4774 : if (TREE_CODE (old_expr) == COMPOUND_EXPR)
2789 : : {
2790 : 102 : tree first = TREE_OPERAND (old_expr, 0);
2791 : 102 : TREE_OPERAND (n->init, 1) = TREE_OPERAND (old_expr, 1);
2792 : 102 : var_nest_node *ins
2793 : 102 : = new var_nest_node(NULL_TREE, first, n->prev, n);
2794 : 102 : flatten_await_stmt (ins, promoted, temps_used,
2795 : : &TREE_OPERAND (n->init, 1));
2796 : 102 : flatten_await_stmt (n, promoted, temps_used, NULL);
2797 : 102 : return;
2798 : : }
2799 : 4672 : if (TREE_CODE (old_expr) != COND_EXPR)
2800 : : break;
2801 : : /* Reconstruct x = t ? y : z;
2802 : : as (void) t ? x = y : x = z; */
2803 : 16 : tree var = TREE_OPERAND (n->init, 0);
2804 : 16 : tree var_type = TREE_TYPE (var);
2805 : 16 : tree cond = COND_EXPR_COND (old_expr);
2806 : : /* We are allowed a void type throw in one or both of the cond
2807 : : expr arms. */
2808 : 16 : tree then_cl = COND_EXPR_THEN (old_expr);
2809 : 16 : if (!VOID_TYPE_P (TREE_TYPE (then_cl)))
2810 : : {
2811 : 16 : gcc_checking_assert (TREE_CODE (then_cl) != STATEMENT_LIST);
2812 : 16 : if (init_expr)
2813 : 16 : then_cl = cp_build_init_expr (var, then_cl);
2814 : : else
2815 : 0 : then_cl = build2 (MODIFY_EXPR, var_type, var, then_cl);
2816 : : }
2817 : 16 : tree else_cl = COND_EXPR_ELSE (old_expr);
2818 : 16 : if (!VOID_TYPE_P (TREE_TYPE (else_cl)))
2819 : : {
2820 : 16 : gcc_checking_assert (TREE_CODE (else_cl) != STATEMENT_LIST);
2821 : 16 : if (init_expr)
2822 : 16 : else_cl = cp_build_init_expr (var, else_cl);
2823 : : else
2824 : 0 : else_cl = build2 (MODIFY_EXPR, var_type, var, else_cl);
2825 : : }
2826 : 16 : n->init = build3 (COND_EXPR, var_type, cond, then_cl, else_cl);
2827 : : }
2828 : : /* FALLTHROUGH */
2829 : 17 : case COND_EXPR:
2830 : 17 : {
2831 : 17 : tree *found;
2832 : 17 : tree cond = COND_EXPR_COND (n->init);
2833 : : /* If the condition contains an await expression, then we need to
2834 : : set that first and use a separate var. */
2835 : 17 : if (cp_walk_tree (&cond, find_any_await, &found, NULL))
2836 : : {
2837 : 17 : tree cond_type = TREE_TYPE (cond);
2838 : 17 : tree cond_var = build_lang_decl (VAR_DECL, NULL_TREE, cond_type);
2839 : 17 : DECL_ARTIFICIAL (cond_var) = true;
2840 : 17 : layout_decl (cond_var, 0);
2841 : 17 : gcc_checking_assert (!TYPE_NEEDS_CONSTRUCTING (cond_type));
2842 : 17 : cond = cp_build_init_expr (cond_var, cond);
2843 : 17 : var_nest_node *ins
2844 : 17 : = new var_nest_node (cond_var, cond, n->prev, n);
2845 : 17 : COND_EXPR_COND (n->init) = cond_var;
2846 : 17 : flatten_await_stmt (ins, promoted, temps_used, NULL);
2847 : : }
2848 : :
2849 : 17 : n->then_cl
2850 : 17 : = new var_nest_node (n->var, COND_EXPR_THEN (n->init), NULL, NULL);
2851 : 17 : n->else_cl
2852 : 17 : = new var_nest_node (n->var, COND_EXPR_ELSE (n->init), NULL, NULL);
2853 : 17 : flatten_await_stmt (n->then_cl, promoted, temps_used, NULL);
2854 : : /* Point to the start of the flattened code. */
2855 : 51 : while (n->then_cl->prev)
2856 : 17 : n->then_cl = n->then_cl->prev;
2857 : 17 : flatten_await_stmt (n->else_cl, promoted, temps_used, NULL);
2858 : 34 : while (n->else_cl->prev)
2859 : 0 : n->else_cl = n->else_cl->prev;
2860 : 17 : return;
2861 : : }
2862 : 10869 : break;
2863 : : }
2864 : 10869 : coro_interesting_subtree v = { NULL, temps_used };
2865 : 10869 : tree t = cp_walk_tree (&n->init, find_interesting_subtree, (void *)&v, NULL);
2866 : 10869 : if (!t)
2867 : : return;
2868 : 3686 : switch (TREE_CODE (t))
2869 : : {
2870 : 0 : default: break;
2871 : 3454 : case CO_AWAIT_EXPR:
2872 : 3454 : {
2873 : : /* Await expressions with initializers have a compiler-temporary
2874 : : as the awaitable. 'promote' this. */
2875 : 3454 : tree var = TREE_OPERAND (t, 1);
2876 : 3454 : bool already_present = promoted->add (var);
2877 : 3454 : gcc_checking_assert (!already_present);
2878 : 3454 : tree init = TREE_OPERAND (t, 2);
2879 : 3454 : switch (TREE_CODE (init))
2880 : : {
2881 : : default: break;
2882 : 3454 : case INIT_EXPR:
2883 : 3454 : case MODIFY_EXPR:
2884 : 3454 : {
2885 : 3454 : tree inner = TREE_OPERAND (init, 1);
2886 : : /* We can have non-lvalue-expressions here, but when we see
2887 : : a target expression, mark it as already used. */
2888 : 3454 : if (TREE_CODE (inner) == TARGET_EXPR)
2889 : : {
2890 : 3454 : temps_used->add (inner);
2891 : 3454 : gcc_checking_assert
2892 : : (TREE_CODE (TREE_OPERAND (inner, 1)) != COND_EXPR);
2893 : : }
2894 : : }
2895 : 3454 : break;
2896 : 0 : case CALL_EXPR:
2897 : : /* If this is a call and not a CTOR, then we didn't expect it. */
2898 : 0 : gcc_checking_assert
2899 : : (DECL_CONSTRUCTOR_P (TREE_OPERAND (CALL_EXPR_FN (init), 0)));
2900 : : break;
2901 : : }
2902 : 3454 : var_nest_node *ins = new var_nest_node (var, init, n->prev, n);
2903 : 3454 : TREE_OPERAND (t, 2) = NULL_TREE;
2904 : 3454 : flatten_await_stmt (ins, promoted, temps_used, NULL);
2905 : 3454 : flatten_await_stmt (n, promoted, temps_used, NULL);
2906 : 3454 : return;
2907 : : }
2908 : 232 : break;
2909 : 232 : case TARGET_EXPR:
2910 : 232 : {
2911 : : /* We have a temporary; promote it, but allow for the idiom in code
2912 : : generated by the compiler like
2913 : : a = (target_expr produces temp, op uses temp). */
2914 : 232 : tree init = t;
2915 : 232 : temps_used->add (init);
2916 : 232 : tree var_type = TREE_TYPE (init);
2917 : 232 : char *buf = xasprintf ("T%03u", (unsigned) temps_used->elements ());
2918 : 232 : tree var = build_lang_decl (VAR_DECL, get_identifier (buf), var_type);
2919 : 232 : DECL_ARTIFICIAL (var) = true;
2920 : 232 : free (buf);
2921 : 232 : bool already_present = promoted->add (var);
2922 : 232 : gcc_checking_assert (!already_present);
2923 : 232 : tree inner = TREE_OPERAND (init, 1);
2924 : 232 : gcc_checking_assert (TREE_CODE (inner) != COND_EXPR);
2925 : 232 : init = cp_build_modify_expr (input_location, var, INIT_EXPR, init,
2926 : : tf_warning_or_error);
2927 : : /* Simplify for the case that we have an init containing the temp
2928 : : alone. */
2929 : 232 : if (t == n->init && n->var == NULL_TREE)
2930 : : {
2931 : 104 : n->var = var;
2932 : 104 : proxy_replace pr = {TREE_OPERAND (t, 0), var};
2933 : 104 : cp_walk_tree (&init, replace_proxy, &pr, NULL);
2934 : 104 : n->init = init;
2935 : 104 : if (replace_in)
2936 : 100 : cp_walk_tree (replace_in, replace_proxy, &pr, NULL);
2937 : 104 : flatten_await_stmt (n, promoted, temps_used, NULL);
2938 : 104 : }
2939 : : else
2940 : : {
2941 : 128 : var_nest_node *ins
2942 : 128 : = new var_nest_node (var, init, n->prev, n);
2943 : : /* We have to replace the target expr... */
2944 : 128 : *v.entry = var;
2945 : : /* ... and any uses of its var. */
2946 : 128 : proxy_replace pr = {TREE_OPERAND (t, 0), var};
2947 : 128 : cp_walk_tree (&n->init, replace_proxy, &pr, NULL);
2948 : : /* Compiler-generated temporaries can also have uses in
2949 : : following arms of compound expressions, which will be listed
2950 : : in 'replace_in' if present. */
2951 : 128 : if (replace_in)
2952 : 1 : cp_walk_tree (replace_in, replace_proxy, &pr, NULL);
2953 : 128 : flatten_await_stmt (ins, promoted, temps_used, NULL);
2954 : 128 : flatten_await_stmt (n, promoted, temps_used, NULL);
2955 : : }
2956 : 232 : return;
2957 : : }
2958 : 0 : break;
2959 : : }
2960 : : }
2961 : :
2962 : : /* Helper for 'process_conditional' that handles recursion into nested
2963 : : conditionals. */
2964 : :
2965 : : static void
2966 : 34 : handle_nested_conditionals (var_nest_node *n, vec<tree>& list,
2967 : : hash_map<tree, tree>& map)
2968 : : {
2969 : 51 : do
2970 : : {
2971 : 51 : if (n->var && DECL_NAME (n->var))
2972 : : {
2973 : 17 : list.safe_push (n->var);
2974 : 17 : if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (n->var)))
2975 : : {
2976 : 0 : bool existed;
2977 : 0 : tree& flag = map.get_or_insert (n->var, &existed);
2978 : 0 : if (!existed)
2979 : : {
2980 : : /* We didn't see this var before and it needs a DTOR, so
2981 : : build a guard variable for it. */
2982 : 0 : char *nam
2983 : 0 : = xasprintf ("%s_guard",
2984 : 0 : IDENTIFIER_POINTER (DECL_NAME (n->var)));
2985 : 0 : flag = build_lang_decl (VAR_DECL, get_identifier (nam),
2986 : : boolean_type_node);
2987 : 0 : free (nam);
2988 : 0 : DECL_ARTIFICIAL (flag) = true;
2989 : : }
2990 : :
2991 : : /* The initializer for this variable is replaced by a compound
2992 : : expression that performs the init and then records that the
2993 : : variable is live (and the DTOR should be run at the scope
2994 : : exit. */
2995 : 0 : tree set_flag = cp_build_init_expr (flag, boolean_true_node);
2996 : 0 : n->init
2997 : 0 : = build2 (COMPOUND_EXPR, boolean_type_node, n->init, set_flag);
2998 : : }
2999 : : }
3000 : 51 : if (TREE_CODE (n->init) == COND_EXPR)
3001 : : {
3002 : 0 : tree new_then = push_stmt_list ();
3003 : 0 : handle_nested_conditionals (n->then_cl, list, map);
3004 : 0 : new_then = pop_stmt_list (new_then);
3005 : 0 : tree new_else = push_stmt_list ();
3006 : 0 : handle_nested_conditionals (n->else_cl, list, map);
3007 : 0 : new_else = pop_stmt_list (new_else);
3008 : 0 : tree new_if
3009 : 0 : = build4 (IF_STMT, void_type_node, COND_EXPR_COND (n->init),
3010 : : new_then, new_else, NULL_TREE);
3011 : 0 : add_stmt (new_if);
3012 : : }
3013 : : else
3014 : 51 : finish_expr_stmt (n->init);
3015 : 51 : n = n->next;
3016 : 51 : } while (n);
3017 : 34 : }
3018 : :
3019 : : /* helper for 'maybe_promote_temps'.
3020 : :
3021 : : When we have a conditional expression which might embed await expressions
3022 : : and/or promoted variables, we need to handle it appropriately.
3023 : :
3024 : : The linked lists for the 'then' and 'else' clauses in a conditional node
3025 : : identify the promoted variables (but these cannot be wrapped in a regular
3026 : : cleanup).
3027 : :
3028 : : So recurse through the lists and build up a composite list of captured vars.
3029 : : Declare these and any guard variables needed to decide if a DTOR should be
3030 : : run. Then embed the conditional into a try-finally expression that handles
3031 : : running each DTOR conditionally on its guard variable. */
3032 : :
3033 : : static void
3034 : 17 : process_conditional (var_nest_node *n, tree& vlist)
3035 : : {
3036 : 17 : tree init = n->init;
3037 : 17 : hash_map<tree, tree> var_flags;
3038 : 17 : auto_vec<tree> var_list;
3039 : 17 : tree new_then = push_stmt_list ();
3040 : 17 : handle_nested_conditionals (n->then_cl, var_list, var_flags);
3041 : 17 : new_then = pop_stmt_list (new_then);
3042 : 17 : tree new_else = push_stmt_list ();
3043 : 17 : handle_nested_conditionals (n->else_cl, var_list, var_flags);
3044 : 17 : new_else = pop_stmt_list (new_else);
3045 : : /* Declare the vars. There are two loops so that the boolean flags are
3046 : : grouped in the frame. */
3047 : 68 : for (unsigned i = 0; i < var_list.length(); i++)
3048 : : {
3049 : 17 : tree var = var_list[i];
3050 : 17 : DECL_CHAIN (var) = vlist;
3051 : 17 : vlist = var;
3052 : 17 : add_decl_expr (var);
3053 : : }
3054 : : /* Define the guard flags for variables that need a DTOR. */
3055 : 68 : for (unsigned i = 0; i < var_list.length(); i++)
3056 : : {
3057 : 17 : tree *flag = var_flags.get (var_list[i]);
3058 : 17 : if (flag)
3059 : : {
3060 : 0 : DECL_INITIAL (*flag) = boolean_false_node;
3061 : 0 : DECL_CHAIN (*flag) = vlist;
3062 : 0 : vlist = *flag;
3063 : 0 : add_decl_expr (*flag);
3064 : : }
3065 : : }
3066 : 17 : tree new_if
3067 : 17 : = build4 (IF_STMT, void_type_node, COND_EXPR_COND (init),
3068 : : new_then, new_else, NULL_TREE);
3069 : : /* Build a set of conditional DTORs. */
3070 : 17 : tree final_actions = push_stmt_list ();
3071 : 51 : while (!var_list.is_empty())
3072 : : {
3073 : 17 : tree var = var_list.pop ();
3074 : 17 : tree *flag = var_flags.get (var);
3075 : 17 : if (!flag)
3076 : 17 : continue;
3077 : 0 : if (tree cleanup = cxx_maybe_build_cleanup (var, tf_warning_or_error))
3078 : : {
3079 : 0 : tree cond_cleanup = begin_if_stmt ();
3080 : 0 : finish_if_stmt_cond (*flag, cond_cleanup);
3081 : 0 : finish_expr_stmt (cleanup);
3082 : 0 : finish_then_clause (cond_cleanup);
3083 : 0 : finish_if_stmt (cond_cleanup);
3084 : : }
3085 : : }
3086 : 17 : final_actions = pop_stmt_list (final_actions);
3087 : 17 : tree try_finally
3088 : 17 : = build2 (TRY_FINALLY_EXPR, void_type_node, new_if, final_actions);
3089 : 17 : add_stmt (try_finally);
3090 : 17 : }
3091 : :
3092 : : /* Given *STMT, that contains at least one await expression.
3093 : :
3094 : : The full expression represented in the original source code will contain
3095 : : suspension points, but it is still required that the lifetime of temporary
3096 : : values extends to the end of the expression.
3097 : :
3098 : : We already have a mechanism to 'promote' user-authored local variables
3099 : : to a coroutine frame counterpart (which allows explicit management of the
3100 : : lifetime across suspensions). The transform here re-writes STMT into
3101 : : a bind expression, promotes temporary values into local variables in that
3102 : : and flattens the statement into a series of cleanups.
3103 : :
3104 : : Conditional expressions are re-written to regular 'if' statements.
3105 : : The cleanups for variables initialized inside a conditional (including
3106 : : nested cases) are wrapped in a try-finally clause, with guard variables
3107 : : to determine which DTORs need to be run. */
3108 : :
3109 : : static tree
3110 : 3460 : maybe_promote_temps (tree *stmt, void *d)
3111 : : {
3112 : 3460 : susp_frame_data *awpts = (susp_frame_data *) d;
3113 : :
3114 : 3460 : location_t sloc = EXPR_LOCATION (*stmt);
3115 : 3460 : tree expr = *stmt;
3116 : : /* Strip off uninteresting wrappers. */
3117 : 3460 : if (TREE_CODE (expr) == CLEANUP_POINT_EXPR)
3118 : 3460 : expr = TREE_OPERAND (expr, 0);
3119 : 3460 : if (TREE_CODE (expr) == EXPR_STMT)
3120 : 3460 : expr = EXPR_STMT_EXPR (expr);
3121 : 3460 : if (TREE_CODE (expr) == CONVERT_EXPR
3122 : 3460 : && VOID_TYPE_P (TREE_TYPE (expr)))
3123 : 432 : expr = TREE_OPERAND (expr, 0);
3124 : 3460 : STRIP_NOPS (expr);
3125 : :
3126 : : /* We walk the statement trees, flattening it into an ordered list of
3127 : : variables with initializers and fragments corresponding to compound
3128 : : expressions, truth or/and if and ternary conditionals. Conditional
3129 : : expressions carry a nested list of fragments for the then and else
3130 : : clauses. We anchor to the 'bottom' of the fragment list; we will write
3131 : : a cleanup nest with one shell for each variable initialized. */
3132 : 3460 : var_nest_node *root = new var_nest_node (NULL_TREE, expr, NULL, NULL);
3133 : : /* Check to see we didn't promote one twice. */
3134 : 3460 : hash_set<tree> promoted_vars;
3135 : 3460 : hash_set<tree> used_temps;
3136 : 3460 : flatten_await_stmt (root, &promoted_vars, &used_temps, NULL);
3137 : :
3138 : 3460 : gcc_checking_assert (root->next == NULL);
3139 : 3460 : tree vlist = NULL_TREE;
3140 : 3460 : var_nest_node *t = root;
3141 : : /* We build the bind scope expression from the bottom-up.
3142 : : EXPR_LIST holds the inner expression nest at the current cleanup
3143 : : level (becoming the final expression list when we've exhausted the
3144 : : number of sub-expression fragments). */
3145 : 3460 : tree expr_list = NULL_TREE;
3146 : 7149 : do
3147 : : {
3148 : 7149 : tree new_list = push_stmt_list ();
3149 : : /* When we have a promoted variable, then add that to the bind scope
3150 : : and initialize it. When there's no promoted variable, we just need
3151 : : to run the initializer.
3152 : : If the initializer is a conditional expression, we need to collect
3153 : : and declare any promoted variables nested within it. DTORs for such
3154 : : variables must be run conditionally too. */
3155 : 7149 : if (t->var)
3156 : : {
3157 : 3686 : tree var = t->var;
3158 : 3686 : DECL_CHAIN (var) = vlist;
3159 : 3686 : vlist = var;
3160 : 3686 : add_decl_expr (var);
3161 : 3686 : if (TREE_CODE (t->init) == COND_EXPR)
3162 : 0 : process_conditional (t, vlist);
3163 : : else
3164 : 3686 : finish_expr_stmt (t->init);
3165 : 3686 : if (tree cleanup = cxx_maybe_build_cleanup (var, tf_warning_or_error))
3166 : : {
3167 : 2146 : tree cl = build_stmt (sloc, CLEANUP_STMT, expr_list, cleanup, var);
3168 : 2146 : add_stmt (cl); /* push this onto the level above. */
3169 : : }
3170 : 1540 : else if (expr_list)
3171 : : {
3172 : 1538 : if (TREE_CODE (expr_list) != STATEMENT_LIST)
3173 : 1382 : add_stmt (expr_list);
3174 : 156 : else if (!tsi_end_p (tsi_start (expr_list)))
3175 : 156 : add_stmt (expr_list);
3176 : : }
3177 : : }
3178 : : else
3179 : : {
3180 : 3463 : if (TREE_CODE (t->init) == COND_EXPR)
3181 : 17 : process_conditional (t, vlist);
3182 : : else
3183 : 3446 : finish_expr_stmt (t->init);
3184 : 3463 : if (expr_list)
3185 : : {
3186 : 7 : if (TREE_CODE (expr_list) != STATEMENT_LIST)
3187 : 3 : add_stmt (expr_list);
3188 : 4 : else if (!tsi_end_p (tsi_start (expr_list)))
3189 : 4 : add_stmt (expr_list);
3190 : : }
3191 : : }
3192 : 7149 : expr_list = pop_stmt_list (new_list);
3193 : 7149 : var_nest_node *old = t;
3194 : 7149 : t = t->prev;
3195 : 7149 : delete old;
3196 : 7149 : } while (t);
3197 : :
3198 : : /* Now produce the bind expression containing the 'promoted' temporaries
3199 : : as its variable list, and the cleanup nest as the statement. */
3200 : 3460 : tree await_bind = build3_loc (sloc, BIND_EXPR, void_type_node,
3201 : : NULL, NULL, NULL);
3202 : 3460 : BIND_EXPR_BODY (await_bind) = expr_list;
3203 : 3460 : BIND_EXPR_VARS (await_bind) = nreverse (vlist);
3204 : 3460 : tree b_block = make_node (BLOCK);
3205 : 3460 : if (!awpts->block_stack->is_empty ())
3206 : : {
3207 : 3460 : tree s_block = awpts->block_stack->last ();
3208 : 3460 : if (s_block)
3209 : : {
3210 : 3460 : BLOCK_SUPERCONTEXT (b_block) = s_block;
3211 : 3460 : BLOCK_CHAIN (b_block) = BLOCK_SUBBLOCKS (s_block);
3212 : 3460 : BLOCK_SUBBLOCKS (s_block) = b_block;
3213 : : }
3214 : : }
3215 : 3460 : BLOCK_VARS (b_block) = BIND_EXPR_VARS (await_bind) ;
3216 : 3460 : BIND_EXPR_BLOCK (await_bind) = b_block;
3217 : 3460 : TREE_SIDE_EFFECTS (await_bind) = TREE_SIDE_EFFECTS (BIND_EXPR_BODY (await_bind));
3218 : 3460 : *stmt = await_bind;
3219 : 3460 : hash_set<tree> visited;
3220 : 3460 : return cp_walk_tree (stmt, register_awaits, d, &visited);
3221 : 3460 : }
3222 : :
3223 : : /* Lightweight callback to determine two key factors:
3224 : : 1) If the statement/expression contains any await expressions.
3225 : : 2) If the statement/expression potentially requires a re-write to handle
3226 : : TRUTH_{AND,OR}IF_EXPRs since, in most cases, they will need expansion
3227 : : so that the await expressions are not processed in the case of the
3228 : : short-circuit arm.
3229 : :
3230 : : CO_YIELD expressions are re-written to their underlying co_await. */
3231 : :
3232 : : static tree
3233 : 139415 : analyze_expression_awaits (tree *stmt, int *do_subtree, void *d)
3234 : : {
3235 : 139415 : susp_frame_data *awpts = (susp_frame_data *) d;
3236 : :
3237 : 139415 : switch (TREE_CODE (*stmt))
3238 : : {
3239 : : default: return NULL_TREE;
3240 : 325 : case CO_YIELD_EXPR:
3241 : : /* co_yield is syntactic sugar, re-write it to co_await. */
3242 : 325 : *stmt = TREE_OPERAND (*stmt, 1);
3243 : : /* FALLTHROUGH */
3244 : 3535 : case CO_AWAIT_EXPR:
3245 : 3535 : awpts->saw_awaits++;
3246 : : /* A non-null initializer for the awaiter means we need to expand. */
3247 : 3535 : if (TREE_OPERAND (*stmt, 2))
3248 : 3454 : awpts->has_awaiter_init = true;
3249 : : break;
3250 : 35 : case TRUTH_ANDIF_EXPR:
3251 : 35 : case TRUTH_ORIF_EXPR:
3252 : 35 : {
3253 : : /* We don't need special action for awaits in the always-executed
3254 : : arm of a TRUTH_IF. */
3255 : 35 : if (tree res = cp_walk_tree (&TREE_OPERAND (*stmt, 0),
3256 : : analyze_expression_awaits, d, NULL))
3257 : : return res;
3258 : : /* However, if there are await expressions on the conditionally
3259 : : executed branch, we must expand the TRUTH_IF to ensure that the
3260 : : expanded await expression control-flow is fully contained in the
3261 : : conditionally executed code. */
3262 : 35 : unsigned aw_count = awpts->saw_awaits;
3263 : 35 : if (tree res = cp_walk_tree (&TREE_OPERAND (*stmt, 1),
3264 : : analyze_expression_awaits, d, NULL))
3265 : : return res;
3266 : 35 : if (awpts->saw_awaits > aw_count)
3267 : : {
3268 : 17 : awpts->truth_aoif_to_expand->add (*stmt);
3269 : 17 : awpts->needs_truth_if_exp = true;
3270 : : }
3271 : : /* We've done the sub-trees here. */
3272 : 35 : *do_subtree = 0;
3273 : : }
3274 : 35 : break;
3275 : : }
3276 : :
3277 : : return NULL_TREE; /* Recurse until done. */
3278 : : }
3279 : :
3280 : : /* Given *EXPR
3281 : : If EXPR contains a TRUTH_{AND,OR}IF_EXPR, TAOIE with an await expr on
3282 : : the conditionally executed branch, change this in a ternary operator.
3283 : :
3284 : : bool not_expr = TAOIE == TRUTH_ORIF_EXPR ? NOT : NOP;
3285 : : not_expr (always-exec expr) ? conditionally-exec expr : not_expr;
3286 : :
3287 : : Apply this recursively to the condition and the conditionally-exec
3288 : : branch. */
3289 : :
3290 : : struct truth_if_transform {
3291 : : tree *orig_stmt;
3292 : : tree scratch_var;
3293 : : hash_set<tree> *truth_aoif_to_expand;
3294 : : };
3295 : :
3296 : : static tree
3297 : 2427 : expand_one_truth_if (tree *expr, int *do_subtree, void *d)
3298 : : {
3299 : 2427 : truth_if_transform *xform = (truth_if_transform *) d;
3300 : :
3301 : 2427 : bool needs_not = false;
3302 : 2427 : switch (TREE_CODE (*expr))
3303 : : {
3304 : : default: break;
3305 : 8 : case TRUTH_ORIF_EXPR:
3306 : 8 : needs_not = true;
3307 : : /* FALLTHROUGH */
3308 : 17 : case TRUTH_ANDIF_EXPR:
3309 : 17 : {
3310 : 17 : if (!xform->truth_aoif_to_expand->contains (*expr))
3311 : : break;
3312 : :
3313 : 17 : location_t sloc = EXPR_LOCATION (*expr);
3314 : : /* Transform truth expression into a cond expression with
3315 : : * the always-executed arm as the condition.
3316 : : * the conditionally-executed arm as the then clause.
3317 : : * the 'else' clause is fixed: 'true' for ||,'false' for &&. */
3318 : 17 : tree cond = TREE_OPERAND (*expr, 0);
3319 : 17 : tree test1 = TREE_OPERAND (*expr, 1);
3320 : 17 : tree fixed = needs_not ? boolean_true_node : boolean_false_node;
3321 : 17 : if (needs_not)
3322 : 8 : cond = build1 (TRUTH_NOT_EXPR, boolean_type_node, cond);
3323 : 17 : tree cond_expr
3324 : 17 : = build3_loc (sloc, COND_EXPR, boolean_type_node,
3325 : : cond, test1, fixed);
3326 : 17 : *expr = cond_expr;
3327 : 17 : if (tree res = cp_walk_tree (&COND_EXPR_COND (*expr),
3328 : : expand_one_truth_if, d, NULL))
3329 : : return res;
3330 : 17 : if (tree res = cp_walk_tree (&COND_EXPR_THEN (*expr),
3331 : : expand_one_truth_if, d, NULL))
3332 : : return res;
3333 : : /* We've manually processed necessary sub-trees here. */
3334 : 17 : *do_subtree = 0;
3335 : : }
3336 : 17 : break;
3337 : : }
3338 : : return NULL_TREE;
3339 : : }
3340 : :
3341 : : /* Helper that adds a new variable of VAR_TYPE to a bind scope BIND, the
3342 : : name is made up from NAM_ROOT, NAM_VERS. */
3343 : :
3344 : : static tree
3345 : 65 : add_var_to_bind (tree& bind, tree var_type,
3346 : : const char *nam_root, unsigned nam_vers)
3347 : : {
3348 : 65 : tree b_vars = BIND_EXPR_VARS (bind);
3349 : : /* Build a variable to hold the condition, this will be included in the
3350 : : frame as a local var. */
3351 : 65 : char *nam = xasprintf ("__%s_%d", nam_root, nam_vers);
3352 : 65 : tree newvar = build_lang_decl (VAR_DECL, get_identifier (nam), var_type);
3353 : 65 : free (nam);
3354 : 65 : DECL_CHAIN (newvar) = b_vars;
3355 : 65 : BIND_EXPR_VARS (bind) = newvar;
3356 : 65 : return newvar;
3357 : : }
3358 : :
3359 : : /* Helper to build and add if (!cond) break; */
3360 : :
3361 : : static void
3362 : 39 : coro_build_add_if_not_cond_break (tree cond)
3363 : : {
3364 : 39 : tree if_stmt = begin_if_stmt ();
3365 : 39 : tree invert = build1 (TRUTH_NOT_EXPR, boolean_type_node, cond);
3366 : 39 : finish_if_stmt_cond (invert, if_stmt);
3367 : 39 : finish_break_stmt ();
3368 : 39 : finish_then_clause (if_stmt);
3369 : 39 : finish_if_stmt (if_stmt);
3370 : 39 : }
3371 : :
3372 : : /* Tree walk callback to replace continue statements with goto label. */
3373 : : static tree
3374 : 1004 : replace_continue (tree *stmt, int *do_subtree, void *d)
3375 : : {
3376 : 1004 : tree expr = *stmt;
3377 : 1004 : if (TREE_CODE (expr) == CLEANUP_POINT_EXPR)
3378 : 36 : expr = TREE_OPERAND (expr, 0);
3379 : 1004 : if (CONVERT_EXPR_P (expr) && VOID_TYPE_P (TREE_TYPE (expr)))
3380 : 36 : expr = TREE_OPERAND (expr, 0);
3381 : 1004 : STRIP_NOPS (expr);
3382 : 1004 : if (!STATEMENT_CLASS_P (expr))
3383 : : return NULL_TREE;
3384 : :
3385 : 40 : switch (TREE_CODE (expr))
3386 : : {
3387 : : /* Unless it's a special case, just walk the subtrees as usual. */
3388 : : default: return NULL_TREE;
3389 : :
3390 : 9 : case CONTINUE_STMT:
3391 : 9 : {
3392 : 9 : tree *label = (tree *)d;
3393 : 9 : location_t loc = EXPR_LOCATION (expr);
3394 : : /* re-write a continue to goto label. */
3395 : 9 : *stmt = build_stmt (loc, GOTO_EXPR, *label);
3396 : 9 : *do_subtree = 0;
3397 : 9 : return NULL_TREE;
3398 : : }
3399 : :
3400 : : /* Statements that do not require recursion. */
3401 : 18 : case DECL_EXPR:
3402 : 18 : case BREAK_STMT:
3403 : 18 : case GOTO_EXPR:
3404 : 18 : case LABEL_EXPR:
3405 : 18 : case CASE_LABEL_EXPR:
3406 : 18 : case ASM_EXPR:
3407 : : /* These must break recursion. */
3408 : 18 : case FOR_STMT:
3409 : 18 : case WHILE_STMT:
3410 : 18 : case DO_STMT:
3411 : 18 : *do_subtree = 0;
3412 : 18 : return NULL_TREE;
3413 : : }
3414 : : }
3415 : :
3416 : : /* Tree walk callback to analyze, register and pre-process statements that
3417 : : contain await expressions. */
3418 : :
3419 : : static tree
3420 : 158983 : await_statement_walker (tree *stmt, int *do_subtree, void *d)
3421 : : {
3422 : 158983 : tree res = NULL_TREE;
3423 : 158983 : susp_frame_data *awpts = (susp_frame_data *) d;
3424 : :
3425 : : /* Process a statement at a time. */
3426 : 158983 : if (TREE_CODE (*stmt) == BIND_EXPR)
3427 : : {
3428 : : /* For conditional expressions, we might wish to add an artificial var
3429 : : to their containing bind expr. */
3430 : 2892 : vec_safe_push (awpts->bind_stack, *stmt);
3431 : : /* We might need to insert a new bind expression, and want to link it
3432 : : into the correct scope, so keep a note of the current block scope. */
3433 : 2892 : tree blk = BIND_EXPR_BLOCK (*stmt);
3434 : 2892 : vec_safe_push (awpts->block_stack, blk);
3435 : 2892 : res = cp_walk_tree (&BIND_EXPR_BODY (*stmt), await_statement_walker,
3436 : : d, NULL);
3437 : 2892 : awpts->block_stack->pop ();
3438 : 2892 : awpts->bind_stack->pop ();
3439 : 2892 : *do_subtree = 0; /* Done subtrees. */
3440 : 2892 : return res;
3441 : : }
3442 : 156091 : else if (TREE_CODE (*stmt) == STATEMENT_LIST)
3443 : : {
3444 : 38034 : for (tree &s : tsi_range (*stmt))
3445 : : {
3446 : 31453 : res = cp_walk_tree (&s, await_statement_walker,
3447 : : d, NULL);
3448 : 31453 : if (res)
3449 : 0 : return res;
3450 : : }
3451 : 6581 : *do_subtree = 0; /* Done subtrees. */
3452 : 6581 : return NULL_TREE;
3453 : : }
3454 : :
3455 : : /* We have something to be handled as a single statement. We have to handle
3456 : : a few statements specially where await statements have to be moved out of
3457 : : constructs. */
3458 : 149510 : tree expr = *stmt;
3459 : 149510 : if (TREE_CODE (*stmt) == CLEANUP_POINT_EXPR)
3460 : 15980 : expr = TREE_OPERAND (expr, 0);
3461 : 149510 : STRIP_NOPS (expr);
3462 : :
3463 : 149510 : if (STATEMENT_CLASS_P (expr))
3464 : 22973 : switch (TREE_CODE (expr))
3465 : : {
3466 : : /* Unless it's a special case, just walk the subtrees as usual. */
3467 : : default: return NULL_TREE;
3468 : :
3469 : : /* When we have a conditional expression, which contains one or more
3470 : : await expressions, we have to break the condition out into a
3471 : : regular statement so that the control flow introduced by the await
3472 : : transforms can be implemented. */
3473 : 1625 : case IF_STMT:
3474 : 1625 : {
3475 : 1625 : tree *await_ptr;
3476 : 1625 : hash_set<tree> visited;
3477 : : /* Transform 'if (cond with awaits) then stmt1 else stmt2' into
3478 : : bool cond = cond with awaits.
3479 : : if (cond) then stmt1 else stmt2. */
3480 : 1625 : tree if_stmt = *stmt;
3481 : : /* We treat the condition as if it was a stand-alone statement,
3482 : : to see if there are any await expressions which will be analyzed
3483 : : and registered. */
3484 : 1625 : if (!(cp_walk_tree (&IF_COND (if_stmt),
3485 : : find_any_await, &await_ptr, &visited)))
3486 : : return NULL_TREE; /* Nothing special to do here. */
3487 : :
3488 : 56 : gcc_checking_assert (!awpts->bind_stack->is_empty());
3489 : 56 : tree& bind_expr = awpts->bind_stack->last ();
3490 : 112 : tree newvar = add_var_to_bind (bind_expr, boolean_type_node,
3491 : 56 : "ifcd", awpts->cond_number++);
3492 : 56 : tree insert_list = push_stmt_list ();
3493 : 56 : tree cond_inner = IF_COND (if_stmt);
3494 : 56 : if (TREE_CODE (cond_inner) == CLEANUP_POINT_EXPR)
3495 : 56 : cond_inner = TREE_OPERAND (cond_inner, 0);
3496 : 56 : add_decl_expr (newvar);
3497 : 56 : location_t sloc = EXPR_LOCATION (IF_COND (if_stmt));
3498 : : /* We want to initialize the new variable with the expression
3499 : : that contains the await(s) and potentially also needs to
3500 : : have truth_if expressions expanded. */
3501 : 56 : tree new_s = cp_build_init_expr (sloc, newvar, cond_inner);
3502 : 56 : finish_expr_stmt (new_s);
3503 : 56 : IF_COND (if_stmt) = newvar;
3504 : 56 : add_stmt (if_stmt);
3505 : 56 : *stmt = pop_stmt_list (insert_list);
3506 : : /* So now walk the new statement list. */
3507 : 56 : res = cp_walk_tree (stmt, await_statement_walker, d, NULL);
3508 : 56 : *do_subtree = 0; /* Done subtrees. */
3509 : 56 : return res;
3510 : 1625 : }
3511 : 134 : break;
3512 : 134 : case FOR_STMT:
3513 : 134 : {
3514 : 134 : tree *await_ptr;
3515 : 134 : hash_set<tree> visited;
3516 : : /* for loops only need special treatment if the condition or the
3517 : : iteration expression contain a co_await. */
3518 : 134 : tree for_stmt = *stmt;
3519 : : /* At present, the FE always generates a separate initializer for
3520 : : the FOR_INIT_STMT, when the expression has an await. Check that
3521 : : this assumption holds in the future. */
3522 : 134 : gcc_checking_assert
3523 : : (!(cp_walk_tree (&FOR_INIT_STMT (for_stmt), find_any_await,
3524 : : &await_ptr, &visited)));
3525 : :
3526 : 134 : visited.empty ();
3527 : 134 : bool for_cond_await
3528 : 134 : = cp_walk_tree (&FOR_COND (for_stmt), find_any_await,
3529 : : &await_ptr, &visited);
3530 : :
3531 : 134 : visited.empty ();
3532 : 134 : bool for_expr_await
3533 : 134 : = cp_walk_tree (&FOR_EXPR (for_stmt), find_any_await,
3534 : : &await_ptr, &visited);
3535 : :
3536 : : /* If the condition has an await, then we will need to rewrite the
3537 : : loop as
3538 : : for (init expression;true;iteration expression) {
3539 : : condition = await expression;
3540 : : if (condition)
3541 : : break;
3542 : : ...
3543 : : }
3544 : : */
3545 : 134 : if (for_cond_await)
3546 : : {
3547 : 19 : tree insert_list = push_stmt_list ();
3548 : : /* This will be expanded when the revised body is handled. */
3549 : 19 : coro_build_add_if_not_cond_break (FOR_COND (for_stmt));
3550 : : /* .. add the original for body. */
3551 : 19 : add_stmt (FOR_BODY (for_stmt));
3552 : : /* To make the new for body. */
3553 : 19 : FOR_BODY (for_stmt) = pop_stmt_list (insert_list);
3554 : 19 : FOR_COND (for_stmt) = boolean_true_node;
3555 : : }
3556 : : /* If the iteration expression has an await, it's a bit more
3557 : : tricky.
3558 : : for (init expression;condition;) {
3559 : : ...
3560 : : iteration_expr_label:
3561 : : iteration expression with await;
3562 : : }
3563 : : but, then we will need to re-write any continue statements into
3564 : : 'goto iteration_expr_label:'.
3565 : : */
3566 : 134 : if (for_expr_await)
3567 : : {
3568 : 18 : location_t sloc = EXPR_LOCATION (FOR_EXPR (for_stmt));
3569 : 18 : tree insert_list = push_stmt_list ();
3570 : : /* The original for body. */
3571 : 18 : add_stmt (FOR_BODY (for_stmt));
3572 : 18 : char *buf = xasprintf ("for.iter.expr.%u", awpts->cond_number++);
3573 : 18 : tree it_expr_label
3574 : 18 : = create_named_label_with_ctx (sloc, buf, NULL_TREE);
3575 : 18 : free (buf);
3576 : 18 : add_stmt (build_stmt (sloc, LABEL_EXPR, it_expr_label));
3577 : 18 : tree for_expr = FOR_EXPR (for_stmt);
3578 : : /* Present the iteration expression as a statement. */
3579 : 18 : if (TREE_CODE (for_expr) == CLEANUP_POINT_EXPR)
3580 : 18 : for_expr = TREE_OPERAND (for_expr, 0);
3581 : 18 : STRIP_NOPS (for_expr);
3582 : 18 : finish_expr_stmt (for_expr);
3583 : 18 : FOR_EXPR (for_stmt) = NULL_TREE;
3584 : 18 : FOR_BODY (for_stmt) = pop_stmt_list (insert_list);
3585 : : /* rewrite continue statements to goto label. */
3586 : 18 : hash_set<tree> visited_continue;
3587 : 18 : if ((res = cp_walk_tree (&FOR_BODY (for_stmt),
3588 : : replace_continue, &it_expr_label, &visited_continue)))
3589 : 0 : return res;
3590 : 18 : }
3591 : :
3592 : : /* So now walk the body statement (list), if there were no await
3593 : : expressions, then this handles the original body - and either
3594 : : way we will have finished with this statement. */
3595 : 134 : res = cp_walk_tree (&FOR_BODY (for_stmt),
3596 : : await_statement_walker, d, NULL);
3597 : 134 : *do_subtree = 0; /* Done subtrees. */
3598 : 134 : return res;
3599 : 134 : }
3600 : 11 : break;
3601 : 11 : case WHILE_STMT:
3602 : 11 : {
3603 : : /* We turn 'while (cond with awaits) stmt' into
3604 : : while (true) {
3605 : : if (!(cond with awaits))
3606 : : break;
3607 : : stmt..
3608 : : } */
3609 : 11 : tree *await_ptr;
3610 : 11 : hash_set<tree> visited;
3611 : 11 : tree while_stmt = *stmt;
3612 : 11 : if (!(cp_walk_tree (&WHILE_COND (while_stmt),
3613 : : find_any_await, &await_ptr, &visited)))
3614 : : return NULL_TREE; /* Nothing special to do here. */
3615 : :
3616 : 11 : tree insert_list = push_stmt_list ();
3617 : 11 : coro_build_add_if_not_cond_break (WHILE_COND (while_stmt));
3618 : : /* The original while body. */
3619 : 11 : add_stmt (WHILE_BODY (while_stmt));
3620 : : /* The new while body. */
3621 : 11 : WHILE_BODY (while_stmt) = pop_stmt_list (insert_list);
3622 : 11 : WHILE_COND (while_stmt) = boolean_true_node;
3623 : : /* So now walk the new statement list. */
3624 : 11 : res = cp_walk_tree (&WHILE_BODY (while_stmt),
3625 : : await_statement_walker, d, NULL);
3626 : 11 : *do_subtree = 0; /* Done subtrees. */
3627 : 11 : return res;
3628 : 11 : }
3629 : 13 : break;
3630 : 13 : case DO_STMT:
3631 : 13 : {
3632 : : /* We turn do stmt while (cond with awaits) into:
3633 : : do {
3634 : : stmt..
3635 : : if (!(cond with awaits))
3636 : : break;
3637 : : } while (true); */
3638 : 13 : tree do_stmt = *stmt;
3639 : 13 : tree *await_ptr;
3640 : 13 : hash_set<tree> visited;
3641 : 13 : if (!(cp_walk_tree (&DO_COND (do_stmt),
3642 : : find_any_await, &await_ptr, &visited)))
3643 : : return NULL_TREE; /* Nothing special to do here. */
3644 : :
3645 : 9 : tree insert_list = push_stmt_list ();
3646 : : /* The original do stmt body. */
3647 : 9 : add_stmt (DO_BODY (do_stmt));
3648 : 9 : coro_build_add_if_not_cond_break (DO_COND (do_stmt));
3649 : : /* The new while body. */
3650 : 9 : DO_BODY (do_stmt) = pop_stmt_list (insert_list);
3651 : 9 : DO_COND (do_stmt) = boolean_true_node;
3652 : : /* So now walk the new statement list. */
3653 : 9 : res = cp_walk_tree (&DO_BODY (do_stmt), await_statement_walker,
3654 : : d, NULL);
3655 : 9 : *do_subtree = 0; /* Done subtrees. */
3656 : 9 : return res;
3657 : 13 : }
3658 : 19 : break;
3659 : 19 : case SWITCH_STMT:
3660 : 19 : {
3661 : : /* We turn 'switch (cond with awaits) stmt' into
3662 : : switch_type cond = cond with awaits
3663 : : switch (cond) stmt. */
3664 : 19 : tree sw_stmt = *stmt;
3665 : 19 : tree *await_ptr;
3666 : 19 : hash_set<tree> visited;
3667 : 19 : if (!(cp_walk_tree (&SWITCH_STMT_COND (sw_stmt),
3668 : : find_any_await, &await_ptr, &visited)))
3669 : : return NULL_TREE; /* Nothing special to do here. */
3670 : :
3671 : 9 : gcc_checking_assert (!awpts->bind_stack->is_empty());
3672 : : /* Build a variable to hold the condition, this will be
3673 : : included in the frame as a local var. */
3674 : 9 : tree& bind_expr = awpts->bind_stack->last ();
3675 : 9 : tree sw_type = SWITCH_STMT_TYPE (sw_stmt);
3676 : 18 : tree newvar = add_var_to_bind (bind_expr, sw_type, "swch",
3677 : 9 : awpts->cond_number++);
3678 : 9 : tree insert_list = push_stmt_list ();
3679 : 9 : add_decl_expr (newvar);
3680 : :
3681 : 9 : tree cond_inner = SWITCH_STMT_COND (sw_stmt);
3682 : 9 : if (TREE_CODE (cond_inner) == CLEANUP_POINT_EXPR)
3683 : 9 : cond_inner = TREE_OPERAND (cond_inner, 0);
3684 : 9 : location_t sloc = EXPR_LOCATION (SWITCH_STMT_COND (sw_stmt));
3685 : 9 : tree new_s = cp_build_init_expr (sloc, newvar,
3686 : : cond_inner);
3687 : 9 : finish_expr_stmt (new_s);
3688 : 9 : SWITCH_STMT_COND (sw_stmt) = newvar;
3689 : : /* Now add the switch statement with the condition re-
3690 : : written to use the local var. */
3691 : 9 : add_stmt (sw_stmt);
3692 : 9 : *stmt = pop_stmt_list (insert_list);
3693 : : /* Process the expanded list. */
3694 : 9 : res = cp_walk_tree (stmt, await_statement_walker,
3695 : : d, NULL);
3696 : 9 : *do_subtree = 0; /* Done subtrees. */
3697 : 9 : return res;
3698 : 19 : }
3699 : 1369 : break;
3700 : 1369 : case CO_RETURN_EXPR:
3701 : 1369 : {
3702 : : /* Expand the co_return as per [stmt.return.coroutine]
3703 : : - for co_return;
3704 : : { p.return_void (); goto final_suspend; }
3705 : : - for co_return [void expr];
3706 : : { expr; p.return_void(); goto final_suspend;}
3707 : : - for co_return [non void expr];
3708 : : { p.return_value(expr); goto final_suspend; } */
3709 : 1369 : location_t loc = EXPR_LOCATION (expr);
3710 : 1369 : tree call = TREE_OPERAND (expr, 1);
3711 : 1369 : expr = TREE_OPERAND (expr, 0);
3712 : 1369 : tree ret_list = push_stmt_list ();
3713 : : /* [stmt.return.coroutine], 2.2
3714 : : If expr is present and void, it is placed immediately before
3715 : : the call for return_void; */
3716 : 1369 : if (expr && VOID_TYPE_P (TREE_TYPE (expr)))
3717 : 11 : finish_expr_stmt (expr);
3718 : : /* Insert p.return_{void,value(expr)}. */
3719 : 1369 : finish_expr_stmt (call);
3720 : 1369 : TREE_USED (awpts->fs_label) = 1;
3721 : 1369 : add_stmt (build_stmt (loc, GOTO_EXPR, awpts->fs_label));
3722 : 1369 : *stmt = pop_stmt_list (ret_list);
3723 : 1369 : res = cp_walk_tree (stmt, await_statement_walker, d, NULL);
3724 : : /* Once this is complete, we will have processed subtrees. */
3725 : 1369 : *do_subtree = 0;
3726 : 1369 : return res;
3727 : : }
3728 : 1314 : break;
3729 : 1314 : case HANDLER:
3730 : 1314 : {
3731 : : /* [expr.await] An await-expression shall appear only in a
3732 : : potentially-evaluated expression within the compound-statement
3733 : : of a function-body outside of a handler. */
3734 : 1314 : tree *await_ptr;
3735 : 1314 : hash_set<tree> visited;
3736 : 1314 : if (!(cp_walk_tree (&HANDLER_BODY (expr), find_any_await,
3737 : : &await_ptr, &visited)))
3738 : : return NULL_TREE; /* All OK. */
3739 : 1 : location_t loc = EXPR_LOCATION (*await_ptr);
3740 : 1 : error_at (loc, "await expressions are not permitted in handlers");
3741 : 1 : return NULL_TREE; /* This is going to fail later anyway. */
3742 : 1314 : }
3743 : 126537 : break;
3744 : : }
3745 : 126537 : else if (EXPR_P (expr))
3746 : : {
3747 : 58746 : hash_set<tree> visited;
3748 : 58746 : tree *await_ptr;
3749 : 58746 : if (!(cp_walk_tree (stmt, find_any_await, &await_ptr, &visited)))
3750 : : return NULL_TREE; /* Nothing special to do here. */
3751 : :
3752 : 3460 : visited.empty ();
3753 : 3460 : awpts->saw_awaits = 0;
3754 : 3460 : hash_set<tree> truth_aoif_to_expand;
3755 : 3460 : awpts->truth_aoif_to_expand = &truth_aoif_to_expand;
3756 : 3460 : awpts->needs_truth_if_exp = false;
3757 : 3460 : awpts->has_awaiter_init = false;
3758 : 3460 : if ((res = cp_walk_tree (stmt, analyze_expression_awaits, d, &visited)))
3759 : : return res;
3760 : 3460 : *do_subtree = 0; /* Done subtrees. */
3761 : 3460 : if (!awpts->saw_awaits)
3762 : : return NULL_TREE; /* Nothing special to do here. */
3763 : :
3764 : 3460 : if (awpts->needs_truth_if_exp)
3765 : : {
3766 : : /* If a truth-and/or-if expression has an await expression in the
3767 : : conditionally-taken branch, then it must be rewritten into a
3768 : : regular conditional. */
3769 : 17 : truth_if_transform xf = {stmt, NULL_TREE, &truth_aoif_to_expand};
3770 : 17 : if ((res = cp_walk_tree (stmt, expand_one_truth_if, &xf, NULL)))
3771 : 0 : return res;
3772 : : }
3773 : : /* Process this statement, which contains at least one await expression
3774 : : to 'promote' temporary values to a coroutine frame slot. */
3775 : 3460 : return maybe_promote_temps (stmt, d);
3776 : 62206 : }
3777 : : /* Continue recursion, if needed. */
3778 : : return res;
3779 : : }
3780 : :
3781 : : /* For figuring out what param usage we have. */
3782 : :
3783 : : struct param_frame_data
3784 : : {
3785 : : tree *field_list;
3786 : : hash_map<tree, param_info> *param_uses;
3787 : : hash_set<tree *> *visited;
3788 : : location_t loc;
3789 : : bool param_seen;
3790 : : };
3791 : :
3792 : : /* A tree walk callback that rewrites each parm use to the local variable
3793 : : that represents its copy in the frame. */
3794 : :
3795 : : static tree
3796 : 99869 : rewrite_param_uses (tree *stmt, int *do_subtree ATTRIBUTE_UNUSED, void *d)
3797 : : {
3798 : 99869 : param_frame_data *data = (param_frame_data *) d;
3799 : :
3800 : : /* For lambda closure content, we have to look specifically. */
3801 : 99869 : if (VAR_P (*stmt) && DECL_HAS_VALUE_EXPR_P (*stmt))
3802 : : {
3803 : 726 : tree t = DECL_VALUE_EXPR (*stmt);
3804 : 726 : return cp_walk_tree (&t, rewrite_param_uses, d, NULL);
3805 : : }
3806 : :
3807 : 99143 : if (unevaluated_p (TREE_CODE (*stmt)))
3808 : : {
3809 : : /* No odr-uses in unevaluated operands. */
3810 : 1 : *do_subtree = 0;
3811 : 1 : return NULL_TREE;
3812 : : }
3813 : :
3814 : 99142 : if (TREE_CODE (*stmt) != PARM_DECL)
3815 : : return NULL_TREE;
3816 : :
3817 : : /* If we already saw the containing expression, then we're done. */
3818 : 960 : if (data->visited->add (stmt))
3819 : : return NULL_TREE;
3820 : :
3821 : 960 : bool existed;
3822 : 960 : param_info &parm = data->param_uses->get_or_insert (*stmt, &existed);
3823 : 960 : gcc_checking_assert (existed);
3824 : :
3825 : 960 : *stmt = parm.copy_var;
3826 : 960 : return NULL_TREE;
3827 : : }
3828 : :
3829 : : /* Build up a set of info that determines how each param copy will be
3830 : : handled. */
3831 : :
3832 : : static void
3833 : 1302 : analyze_fn_parms (tree orig, hash_map<tree, param_info> *param_uses)
3834 : : {
3835 : 1302 : if (!DECL_ARGUMENTS (orig))
3836 : : return;
3837 : :
3838 : : /* Build a hash map with an entry for each param.
3839 : : The key is the param tree.
3840 : : Then we have an entry for the frame field name.
3841 : : Then a cache for the field ref when we come to use it.
3842 : : Then a tree list of the uses.
3843 : : The second two entries start out empty - and only get populated
3844 : : when we see uses. */
3845 : 811 : bool lambda_p = LAMBDA_FUNCTION_P (orig);
3846 : :
3847 : 648 : unsigned no_name_parm = 0;
3848 : 1487 : for (tree arg = DECL_ARGUMENTS (orig); arg != NULL; arg = DECL_CHAIN (arg))
3849 : : {
3850 : 839 : bool existed;
3851 : 839 : param_info &parm = param_uses->get_or_insert (arg, &existed);
3852 : 839 : gcc_checking_assert (!existed);
3853 : 839 : parm.body_uses = NULL;
3854 : 839 : tree actual_type = TREE_TYPE (arg);
3855 : 839 : actual_type = complete_type_or_else (actual_type, orig);
3856 : 839 : if (actual_type == NULL_TREE)
3857 : 0 : actual_type = error_mark_node;
3858 : 839 : parm.orig_type = actual_type;
3859 : 839 : parm.by_ref = parm.pt_ref = parm.rv_ref = false;
3860 : 839 : if (TREE_CODE (actual_type) == REFERENCE_TYPE)
3861 : : {
3862 : : /* If the user passes by reference, then we will save the
3863 : : pointer to the original. As noted in
3864 : : [dcl.fct.def.coroutine] / 13, if the lifetime of the
3865 : : referenced item ends and then the coroutine is resumed,
3866 : : we have UB; well, the user asked for it. */
3867 : 108 : if (TYPE_REF_IS_RVALUE (actual_type))
3868 : 32 : parm.rv_ref = true;
3869 : : else
3870 : 76 : parm.pt_ref = true;
3871 : : }
3872 : 731 : else if (TYPE_REF_P (DECL_ARG_TYPE (arg)))
3873 : 81 : parm.by_ref = true;
3874 : :
3875 : 839 : parm.frame_type = actual_type;
3876 : :
3877 : 839 : parm.this_ptr = is_this_parameter (arg);
3878 : 839 : parm.lambda_cobj = lambda_p && DECL_NAME (arg) == closure_identifier;
3879 : :
3880 : 839 : tree name = DECL_NAME (arg);
3881 : 839 : if (!name)
3882 : : {
3883 : 18 : char *buf = xasprintf ("_Coro_unnamed_parm_%d", no_name_parm++);
3884 : 18 : name = get_identifier (buf);
3885 : 18 : free (buf);
3886 : : }
3887 : 839 : parm.field_id = name;
3888 : :
3889 : 839 : if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (parm.frame_type))
3890 : : {
3891 : 167 : char *buf = xasprintf ("%s%s_live", DECL_NAME (arg) ? "_Coro_" : "",
3892 : 81 : IDENTIFIER_POINTER (name));
3893 : 81 : parm.guard_var
3894 : 81 : = coro_build_artificial_var (UNKNOWN_LOCATION, get_identifier (buf),
3895 : : boolean_type_node, orig,
3896 : : boolean_false_node);
3897 : 81 : free (buf);
3898 : 81 : parm.trivial_dtor = false;
3899 : : }
3900 : : else
3901 : 758 : parm.trivial_dtor = true;
3902 : : }
3903 : : }
3904 : :
3905 : : /* Small helper for the repetitive task of adding a new field to the coro
3906 : : frame type. */
3907 : :
3908 : : static tree
3909 : 14477 : coro_make_frame_entry (tree *field_list, const char *name, tree fld_type,
3910 : : location_t loc)
3911 : : {
3912 : 14477 : tree id = get_identifier (name);
3913 : 14477 : tree decl = build_decl (loc, FIELD_DECL, id, fld_type);
3914 : 14477 : DECL_CHAIN (decl) = *field_list;
3915 : 14477 : *field_list = decl;
3916 : 14477 : return id;
3917 : : }
3918 : :
3919 : : /* A tree-walk callback that processes one bind expression noting local
3920 : : variables, and making a coroutine frame slot available for those that
3921 : : need it, so that they can be 'promoted' across suspension points. */
3922 : :
3923 : : static tree
3924 : 427554 : register_local_var_uses (tree *stmt, int *do_subtree, void *d)
3925 : : {
3926 : 427554 : local_vars_frame_data *lvd = (local_vars_frame_data *) d;
3927 : :
3928 : : /* As we enter a bind expression - record the vars there and then recurse.
3929 : : As we exit drop the nest depth.
3930 : : The bind index is a growing count of how many bind indices we've seen.
3931 : : We build a space in the frame for each local var. */
3932 : :
3933 : 427554 : if (TREE_CODE (*stmt) == BIND_EXPR)
3934 : : {
3935 : 6353 : tree lvar;
3936 : 6353 : unsigned serial = 0;
3937 : 20973 : for (lvar = BIND_EXPR_VARS (*stmt); lvar != NULL;
3938 : 14620 : lvar = DECL_CHAIN (lvar))
3939 : : {
3940 : 14620 : bool existed;
3941 : 14620 : local_var_info &local_var
3942 : 14620 : = lvd->local_var_uses->get_or_insert (lvar, &existed);
3943 : 14620 : gcc_checking_assert (!existed);
3944 : 14620 : local_var.def_loc = DECL_SOURCE_LOCATION (lvar);
3945 : 14620 : tree lvtype = TREE_TYPE (lvar);
3946 : 14620 : local_var.frame_type = lvtype;
3947 : 14620 : local_var.field_idx = local_var.field_id = NULL_TREE;
3948 : :
3949 : : /* Make sure that we only present vars to the tests below. */
3950 : 14620 : if (TREE_CODE (lvar) != PARM_DECL
3951 : 14620 : && TREE_CODE (lvar) != VAR_DECL)
3952 : 143 : continue;
3953 : :
3954 : : /* We don't move static vars into the frame. */
3955 : 14599 : local_var.is_static = TREE_STATIC (lvar);
3956 : 14599 : if (local_var.is_static)
3957 : 3 : continue;
3958 : :
3959 : 14596 : poly_uint64 size;
3960 : 14597 : if (TREE_CODE (lvtype) == ARRAY_TYPE
3961 : 14596 : && !poly_int_tree_p (DECL_SIZE_UNIT (lvar), &size))
3962 : : {
3963 : 1 : sorry_at (local_var.def_loc, "variable length arrays are not"
3964 : : " yet supported in coroutines");
3965 : : /* Ignore it, this is broken anyway. */
3966 : 1 : continue;
3967 : : }
3968 : :
3969 : 14595 : lvd->local_var_seen = true;
3970 : : /* If this var is a lambda capture proxy, we want to leave it alone,
3971 : : and later rewrite the DECL_VALUE_EXPR to indirect through the
3972 : : frame copy of the pointer to the lambda closure object. */
3973 : 14595 : local_var.is_lambda_capture = is_capture_proxy (lvar);
3974 : 14595 : if (local_var.is_lambda_capture)
3975 : 110 : continue;
3976 : :
3977 : : /* If a variable has a value expression, then that's what needs
3978 : : to be processed. */
3979 : 14485 : local_var.has_value_expr_p = DECL_HAS_VALUE_EXPR_P (lvar);
3980 : 14485 : if (local_var.has_value_expr_p)
3981 : 8 : continue;
3982 : :
3983 : : /* Make names depth+index unique, so that we can support nested
3984 : : scopes with identically named locals and still be able to
3985 : : identify them in the coroutine frame. */
3986 : 14477 : tree lvname = DECL_NAME (lvar);
3987 : 14477 : char *buf = NULL;
3988 : :
3989 : : /* The outermost bind scope contains the artificial variables that
3990 : : we inject to implement the coro state machine. We want to be able
3991 : : to inspect these in debugging. */
3992 : 14477 : if (lvname != NULL_TREE && lvd->nest_depth == 0)
3993 : 9946 : buf = xasprintf ("%s", IDENTIFIER_POINTER (lvname));
3994 : 4497 : else if (lvname != NULL_TREE)
3995 : 4497 : buf = xasprintf ("%s_%u_%u", IDENTIFIER_POINTER (lvname),
3996 : : lvd->nest_depth, lvd->bind_indx);
3997 : : else
3998 : 34 : buf = xasprintf ("_D%u_%u_%u", lvd->nest_depth, lvd->bind_indx,
3999 : : serial++);
4000 : :
4001 : : /* TODO: Figure out if we should build a local type that has any
4002 : : excess alignment or size from the original decl. */
4003 : 14477 : local_var.field_id = coro_make_frame_entry (lvd->field_list, buf,
4004 : : lvtype, lvd->loc);
4005 : 14477 : free (buf);
4006 : : /* We don't walk any of the local var sub-trees, they won't contain
4007 : : any bind exprs. */
4008 : : }
4009 : 6353 : lvd->bind_indx++;
4010 : 6353 : lvd->nest_depth++;
4011 : 6353 : cp_walk_tree (&BIND_EXPR_BODY (*stmt), register_local_var_uses, d, NULL);
4012 : 6353 : *do_subtree = 0; /* We've done this. */
4013 : 6353 : lvd->nest_depth--;
4014 : : }
4015 : 427554 : return NULL_TREE;
4016 : : }
4017 : :
4018 : : /* Build, return FUNCTION_DECL node based on ORIG with a type FN_TYPE which has
4019 : : a single argument of type CORO_FRAME_PTR. Build the actor function if
4020 : : ACTOR_P is true, otherwise the destroy. */
4021 : :
4022 : : static tree
4023 : 2604 : coro_build_actor_or_destroy_function (tree orig, tree fn_type,
4024 : : tree coro_frame_ptr, bool actor_p)
4025 : : {
4026 : 2604 : location_t loc = DECL_SOURCE_LOCATION (orig);
4027 : 2604 : tree fn
4028 : 2604 : = build_lang_decl (FUNCTION_DECL, copy_node (DECL_NAME (orig)), fn_type);
4029 : :
4030 : : /* Allow for locating the ramp (original) function from this one. */
4031 : 2604 : if (!to_ramp)
4032 : 1133 : to_ramp = hash_map<tree, tree>::create_ggc (10);
4033 : 2604 : to_ramp->put (fn, orig);
4034 : :
4035 : 2604 : DECL_CONTEXT (fn) = DECL_CONTEXT (orig);
4036 : 2604 : DECL_SOURCE_LOCATION (fn) = loc;
4037 : 2604 : DECL_ARTIFICIAL (fn) = true;
4038 : 2604 : DECL_INITIAL (fn) = error_mark_node;
4039 : :
4040 : 2604 : tree id = get_identifier ("frame_ptr");
4041 : 2604 : tree fp = build_lang_decl (PARM_DECL, id, coro_frame_ptr);
4042 : 2604 : DECL_ARTIFICIAL (fp) = true;
4043 : 2604 : DECL_CONTEXT (fp) = fn;
4044 : 2604 : DECL_ARG_TYPE (fp) = type_passed_as (coro_frame_ptr);
4045 : 2604 : DECL_ARGUMENTS (fn) = fp;
4046 : :
4047 : : /* Copy selected attributes from the original function. */
4048 : 2604 : TREE_USED (fn) = TREE_USED (orig);
4049 : 2604 : if (DECL_SECTION_NAME (orig))
4050 : 0 : set_decl_section_name (fn, orig);
4051 : : /* Copy any alignment that the FE added. */
4052 : 2604 : if (DECL_ALIGN (orig))
4053 : 2604 : SET_DECL_ALIGN (fn, DECL_ALIGN (orig));
4054 : : /* Copy any alignment the user added. */
4055 : 2604 : DECL_USER_ALIGN (fn) = DECL_USER_ALIGN (orig);
4056 : : /* Apply attributes from the original fn. */
4057 : 2604 : DECL_ATTRIBUTES (fn) = copy_list (DECL_ATTRIBUTES (orig));
4058 : : /* but we do not want ones for contracts. */
4059 : 2604 : remove_contract_attributes (fn);
4060 : :
4061 : : /* A void return. */
4062 : 2604 : tree resdecl = build_decl (loc, RESULT_DECL, 0, void_type_node);
4063 : 2604 : DECL_CONTEXT (resdecl) = fn;
4064 : 2604 : DECL_ARTIFICIAL (resdecl) = 1;
4065 : 2604 : DECL_IGNORED_P (resdecl) = 1;
4066 : 2604 : DECL_RESULT (fn) = resdecl;
4067 : :
4068 : : /* Set up a means to find out if a decl is one of the helpers and, if so,
4069 : : which one. */
4070 : 2604 : if (coroutine_info *info = get_coroutine_info (orig))
4071 : : {
4072 : 2604 : gcc_checking_assert ((actor_p && info->actor_decl == NULL_TREE)
4073 : : || info->destroy_decl == NULL_TREE);
4074 : 2604 : if (actor_p)
4075 : 1302 : info->actor_decl = fn;
4076 : : else
4077 : 1302 : info->destroy_decl = fn;
4078 : : }
4079 : 2604 : return fn;
4080 : : }
4081 : :
4082 : : /* Re-write the body as per [dcl.fct.def.coroutine] / 5. */
4083 : :
4084 : : void
4085 : 1302 : cp_coroutine_transform::wrap_original_function_body ()
4086 : : {
4087 : : /* Avoid the code here attaching a location that makes the debugger jump. */
4088 : 1302 : iloc_sentinel stable_input_loc (fn_start);
4089 : 1302 : location_t loc = UNKNOWN_LOCATION;
4090 : 1302 : input_location = loc;
4091 : :
4092 : : /* This will be our new outer scope. */
4093 : 1302 : tree update_body
4094 : 1302 : = build3_loc (loc, BIND_EXPR, void_type_node, NULL, NULL, NULL);
4095 : 1302 : tree top_block = make_node (BLOCK);
4096 : 1302 : BIND_EXPR_BLOCK (update_body) = top_block;
4097 : 1302 : BIND_EXPR_BODY (update_body) = push_stmt_list ();
4098 : :
4099 : : /* If the function has a top level bind expression, then connect that
4100 : : after first making sure we give it a new block. */
4101 : 1302 : tree first = expr_first (coroutine_body);
4102 : 1302 : if (first && TREE_CODE (first) == BIND_EXPR)
4103 : : {
4104 : 577 : tree block = BIND_EXPR_BLOCK (first);
4105 : 577 : gcc_checking_assert (block);
4106 : 577 : gcc_checking_assert (BLOCK_SUPERCONTEXT (block) == NULL_TREE);
4107 : 577 : gcc_checking_assert (BLOCK_CHAIN (block) == NULL_TREE);
4108 : : /* Replace the top block to avoid issues with locations for args
4109 : : appearing to be in a non-existent place. */
4110 : 577 : tree replace_blk = make_node (BLOCK);
4111 : 577 : BLOCK_VARS (replace_blk) = BLOCK_VARS (block);
4112 : 577 : BLOCK_SUBBLOCKS (replace_blk) = BLOCK_SUBBLOCKS (block);
4113 : 812 : for (tree b = BLOCK_SUBBLOCKS (replace_blk); b; b = BLOCK_CHAIN (b))
4114 : 235 : BLOCK_SUPERCONTEXT (b) = replace_blk;
4115 : 577 : BIND_EXPR_BLOCK (first) = replace_blk;
4116 : : /* The top block has one child, so far, and we have now got a
4117 : : superblock. */
4118 : 577 : BLOCK_SUPERCONTEXT (replace_blk) = top_block;
4119 : 577 : BLOCK_SUBBLOCKS (top_block) = replace_blk;
4120 : 577 : }
4121 : : else
4122 : : {
4123 : : /* We are missing a top level BIND_EXPR. We need one to ensure that we
4124 : : don't shuffle around the coroutine frame and corrupt it. */
4125 : 725 : tree bind_wrap = build3_loc (loc, BIND_EXPR, void_type_node,
4126 : : NULL, NULL, NULL);
4127 : 725 : BIND_EXPR_BODY (bind_wrap) = coroutine_body;
4128 : : /* Ensure we have a block to connect up the scopes. */
4129 : 725 : tree new_blk = make_node (BLOCK);
4130 : 725 : BIND_EXPR_BLOCK (bind_wrap) = new_blk;
4131 : 725 : BLOCK_SUBBLOCKS (top_block) = new_blk;
4132 : 725 : coroutine_body = bind_wrap;
4133 : : }
4134 : :
4135 : : /* Wrap the function body in a try {} catch (...) {} block, if exceptions
4136 : : are enabled. */
4137 : 1302 : tree var_list = NULL_TREE;
4138 : 1302 : tree initial_await = build_init_or_final_await (fn_start, false);
4139 : :
4140 : : /* [stmt.return.coroutine] / 3
4141 : : If p.return_void() is a valid expression, flowing off the end of a
4142 : : coroutine is equivalent to a co_return with no operand; otherwise
4143 : : flowing off the end of a coroutine results in undefined behavior. */
4144 : 1302 : tree return_void
4145 : 1302 : = get_coroutine_return_void_expr (orig_fn_decl, loc, false);
4146 : :
4147 : : /* The pointer to the resume function. */
4148 : 1302 : tree resume_fn_ptr
4149 : 1302 : = coro_build_artificial_var (loc, coro_resume_fn_id,
4150 : : act_des_fn_ptr_type, orig_fn_decl, NULL_TREE);
4151 : 1302 : DECL_CHAIN (resume_fn_ptr) = var_list;
4152 : 1302 : var_list = resume_fn_ptr;
4153 : 1302 : add_decl_expr (resume_fn_ptr);
4154 : :
4155 : : /* We will need to be able to set the resume function pointer to nullptr
4156 : : to signal that the coroutine is 'done'. */
4157 : 1302 : tree zero_resume
4158 : 1302 : = build1 (CONVERT_EXPR, act_des_fn_ptr_type, nullptr_node);
4159 : :
4160 : : /* The pointer to the destroy function. */
4161 : 1302 : tree var
4162 : 1302 : = coro_build_artificial_var (loc, coro_destroy_fn_id,
4163 : : act_des_fn_ptr_type, orig_fn_decl, NULL_TREE);
4164 : 1302 : DECL_CHAIN (var) = var_list;
4165 : 1302 : var_list = var;
4166 : 1302 : add_decl_expr (var);
4167 : :
4168 : : /* The promise was created on demand when parsing we now link it into
4169 : : our scope. */
4170 : 1302 : tree promise = get_coroutine_promise_proxy (orig_fn_decl);
4171 : 1302 : DECL_CONTEXT (promise) = orig_fn_decl;
4172 : 1302 : DECL_SOURCE_LOCATION (promise) = loc;
4173 : 1302 : DECL_CHAIN (promise) = var_list;
4174 : 1302 : var_list = promise;
4175 : 1302 : add_decl_expr (promise);
4176 : :
4177 : : /* We need a handle to this coroutine, which is passed to every
4178 : : await_suspend(). This was created on demand when parsing we now link it
4179 : : into our scope. */
4180 : 1302 : var = get_coroutine_self_handle_proxy (orig_fn_decl);
4181 : 1302 : DECL_CONTEXT (var) = orig_fn_decl;
4182 : 1302 : DECL_SOURCE_LOCATION (var) = loc;
4183 : 1302 : DECL_CHAIN (var) = var_list;
4184 : 1302 : var_list = var;
4185 : 1302 : add_decl_expr (var);
4186 : :
4187 : : /* If we have function parms, then these will be copied to the coroutine
4188 : : frame as per [dcl.fct.def.coroutine] / 13.
4189 : : Here, we create a local (proxy) variable for each parm, since the original
4190 : : parms will be out of scope once the ramp has finished. The proxy vars will
4191 : : get DECL_VALUE_EXPRs pointing to the frame copies, so that we can interact
4192 : : with them in the debugger. */
4193 : 1302 : if (DECL_ARGUMENTS (orig_fn_decl))
4194 : : {
4195 : : /* Add a local var for each parm. */
4196 : 1487 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
4197 : 839 : arg = DECL_CHAIN (arg))
4198 : : {
4199 : 839 : param_info *parm_i = param_uses.get (arg);
4200 : 839 : gcc_checking_assert (parm_i);
4201 : 839 : parm_i->copy_var
4202 : 839 : = build_lang_decl (VAR_DECL, parm_i->field_id, TREE_TYPE (arg));
4203 : 839 : DECL_SOURCE_LOCATION (parm_i->copy_var) = DECL_SOURCE_LOCATION (arg);
4204 : 839 : DECL_CONTEXT (parm_i->copy_var) = orig_fn_decl;
4205 : 839 : DECL_ARTIFICIAL (parm_i->copy_var) = true;
4206 : 839 : DECL_CHAIN (parm_i->copy_var) = var_list;
4207 : 839 : var_list = parm_i->copy_var;
4208 : 839 : add_decl_expr (parm_i->copy_var);
4209 : : }
4210 : :
4211 : : /* Now replace all uses of the parms in the function body with the proxy
4212 : : vars. We want to this to apply to every instance of param's use, so
4213 : : don't include a 'visited' hash_set on the tree walk, however we will
4214 : : arrange to visit each containing expression only once. */
4215 : 648 : hash_set<tree *> visited;
4216 : 648 : param_frame_data param_data = {NULL, ¶m_uses,
4217 : 648 : &visited, loc, false};
4218 : 648 : cp_walk_tree (&coroutine_body, rewrite_param_uses, ¶m_data, NULL);
4219 : 648 : }
4220 : :
4221 : : /* We create a resume index, this is initialized in the ramp. */
4222 : 1302 : resume_idx_var
4223 : 1302 : = coro_build_artificial_var (loc, coro_resume_index_id,
4224 : : short_unsigned_type_node, orig_fn_decl,
4225 : : NULL_TREE);
4226 : 1302 : DECL_CHAIN (resume_idx_var) = var_list;
4227 : 1302 : var_list = resume_idx_var;
4228 : 1302 : add_decl_expr (resume_idx_var);
4229 : :
4230 : : /* If the coroutine has a frame that needs to be freed, this will be set by
4231 : : the ramp. */
4232 : 1302 : var = coro_build_artificial_var (fn_start, coro_frame_needs_free_id,
4233 : : boolean_type_node, orig_fn_decl, NULL_TREE);
4234 : 1302 : DECL_CHAIN (var) = var_list;
4235 : 1302 : var_list = var;
4236 : 1302 : add_decl_expr (var);
4237 : :
4238 : 1302 : if (flag_exceptions)
4239 : : {
4240 : : /* Build promise.unhandled_exception(); */
4241 : 1295 : tree ueh
4242 : 1295 : = coro_build_promise_expression (orig_fn_decl, promise,
4243 : : coro_unhandled_exception_identifier,
4244 : : fn_start, NULL, /*musthave=*/true);
4245 : : /* Create and initialize the initial-await-resume-called variable per
4246 : : [dcl.fct.def.coroutine] / 5.3. */
4247 : 1295 : tree i_a_r_c
4248 : 1295 : = coro_build_artificial_var (loc, coro_frame_i_a_r_c_id,
4249 : : boolean_type_node, orig_fn_decl,
4250 : : boolean_false_node);
4251 : 1295 : DECL_CHAIN (i_a_r_c) = var_list;
4252 : 1295 : var_list = i_a_r_c;
4253 : 1295 : add_decl_expr (i_a_r_c);
4254 : : /* Start the try-catch. */
4255 : 1295 : tree tcb = build_stmt (loc, TRY_BLOCK, NULL_TREE, NULL_TREE);
4256 : 1295 : add_stmt (tcb);
4257 : 1295 : TRY_STMTS (tcb) = push_stmt_list ();
4258 : 1295 : if (initial_await != error_mark_node)
4259 : : {
4260 : : /* Build a compound expression that sets the
4261 : : initial-await-resume-called variable true and then calls the
4262 : : initial suspend expression await resume.
4263 : : In the case that the user decides to make the initial await
4264 : : await_resume() return a value, we need to discard it and, it is
4265 : : a reference type, look past the indirection. */
4266 : 1293 : if (INDIRECT_REF_P (initial_await))
4267 : 1 : initial_await = TREE_OPERAND (initial_await, 0);
4268 : : /* In the case that the initial_await returns a target expression
4269 : : we might need to look through that to update the await expr. */
4270 : 1293 : tree iaw = initial_await;
4271 : 1293 : if (TREE_CODE (iaw) == TARGET_EXPR)
4272 : 1 : iaw = TARGET_EXPR_INITIAL (iaw);
4273 : 1293 : gcc_checking_assert (TREE_CODE (iaw) == CO_AWAIT_EXPR);
4274 : 1293 : tree vec = TREE_OPERAND (iaw, 3);
4275 : 1293 : tree aw_r = TREE_VEC_ELT (vec, 2);
4276 : 1293 : aw_r = convert_to_void (aw_r, ICV_STATEMENT, tf_warning_or_error);
4277 : 1293 : tree update = build2 (MODIFY_EXPR, boolean_type_node, i_a_r_c,
4278 : : boolean_true_node);
4279 : 1293 : aw_r = cp_build_compound_expr (update, aw_r, tf_warning_or_error);
4280 : 1293 : TREE_VEC_ELT (vec, 2) = aw_r;
4281 : : }
4282 : : /* Add the initial await to the start of the user-authored function. */
4283 : 1295 : finish_expr_stmt (initial_await);
4284 : : /* Append the original function body. */
4285 : 1295 : add_stmt (coroutine_body);
4286 : 1295 : if (return_void)
4287 : 413 : add_stmt (return_void);
4288 : 1295 : TRY_STMTS (tcb) = pop_stmt_list (TRY_STMTS (tcb));
4289 : 1295 : TRY_HANDLERS (tcb) = push_stmt_list ();
4290 : : /* Mimic what the parser does for the catch. */
4291 : 1295 : tree handler = begin_handler ();
4292 : 1295 : finish_handler_parms (NULL_TREE, handler); /* catch (...) */
4293 : :
4294 : : /* Get the initial await resume called value. */
4295 : 1295 : tree not_iarc_if = begin_if_stmt ();
4296 : 1295 : tree not_iarc = build1_loc (loc, TRUTH_NOT_EXPR,
4297 : : boolean_type_node, i_a_r_c);
4298 : 1295 : finish_if_stmt_cond (not_iarc, not_iarc_if);
4299 : : /* If the initial await resume called value is false, rethrow... */
4300 : 1295 : tree rethrow = build_throw (loc, NULL_TREE, tf_warning_or_error);
4301 : 1295 : suppress_warning (rethrow);
4302 : 1295 : finish_expr_stmt (rethrow);
4303 : 1295 : finish_then_clause (not_iarc_if);
4304 : 1295 : tree iarc_scope = IF_SCOPE (not_iarc_if);
4305 : 1295 : IF_SCOPE (not_iarc_if) = NULL;
4306 : 1295 : not_iarc_if = do_poplevel (iarc_scope);
4307 : 1295 : add_stmt (not_iarc_if);
4308 : : /* ... else call the promise unhandled exception method
4309 : : but first we set done = true and the resume index to 0.
4310 : : If the unhandled exception method returns, then we continue
4311 : : to the final await expression (which duplicates the clearing of
4312 : : the field). */
4313 : 1295 : tree r = build2_loc (loc, MODIFY_EXPR, act_des_fn_ptr_type, resume_fn_ptr,
4314 : : zero_resume);
4315 : 1295 : finish_expr_stmt (r);
4316 : 1295 : tree short_zero = build_int_cst (short_unsigned_type_node, 0);
4317 : 1295 : r = build2 (MODIFY_EXPR, short_unsigned_type_node, resume_idx_var,
4318 : : short_zero);
4319 : 1295 : finish_expr_stmt (r);
4320 : 1295 : finish_expr_stmt (ueh);
4321 : 1295 : finish_handler (handler);
4322 : 1295 : TRY_HANDLERS (tcb) = pop_stmt_list (TRY_HANDLERS (tcb));
4323 : : }
4324 : : else
4325 : : {
4326 : 7 : if (pedantic)
4327 : : {
4328 : : /* We still try to look for the promise method and warn if it's not
4329 : : present. */
4330 : 5 : tree ueh_meth
4331 : 5 : = lookup_promise_method (orig_fn_decl,
4332 : : coro_unhandled_exception_identifier,
4333 : : fn_start, /*musthave=*/false);
4334 : 5 : if (!ueh_meth || ueh_meth == error_mark_node)
4335 : 2 : warning_at (fn_start, 0, "no member named %qE in %qT",
4336 : : coro_unhandled_exception_identifier,
4337 : : get_coroutine_promise_type (orig_fn_decl));
4338 : : }
4339 : : /* Else we don't check and don't care if the method is missing..
4340 : : just add the initial suspend, function and return. */
4341 : 7 : finish_expr_stmt (initial_await);
4342 : : /* Append the original function body. */
4343 : 7 : add_stmt (coroutine_body);
4344 : 7 : if (return_void)
4345 : 6 : add_stmt (return_void);
4346 : : }
4347 : :
4348 : : /* co_return branches to the final_suspend label, so declare that now. */
4349 : 1302 : fs_label
4350 : 1302 : = create_named_label_with_ctx (loc, "final.suspend", NULL_TREE);
4351 : 1302 : add_stmt (build_stmt (loc, LABEL_EXPR, fs_label));
4352 : :
4353 : : /* Before entering the final suspend point, we signal that this point has
4354 : : been reached by setting the resume function pointer to zero (this is
4355 : : what the 'done()' builtin tests) as per the current ABI. */
4356 : 1302 : zero_resume = build2_loc (loc, MODIFY_EXPR, act_des_fn_ptr_type,
4357 : : resume_fn_ptr, zero_resume);
4358 : 1302 : finish_expr_stmt (zero_resume);
4359 : 1302 : finish_expr_stmt (build_init_or_final_await (fn_start, true));
4360 : 1302 : BIND_EXPR_BODY (update_body) = pop_stmt_list (BIND_EXPR_BODY (update_body));
4361 : 1302 : BIND_EXPR_VARS (update_body) = nreverse (var_list);
4362 : 1302 : BLOCK_VARS (top_block) = BIND_EXPR_VARS (update_body);
4363 : :
4364 : 1302 : coroutine_body = update_body;
4365 : 1302 : }
4366 : :
4367 : : /* Extract the body of the function we are going to outline, leaving
4368 : : to original function decl ready to build the ramp. */
4369 : :
4370 : : static tree
4371 : 1323 : split_coroutine_body_from_ramp (tree fndecl)
4372 : : {
4373 : : /* Sanity-check and punt if we have a nonsense tree because of earlier
4374 : : parse errors, perhaps. */
4375 : 1323 : if (!current_binding_level
4376 : 1323 : || current_binding_level->kind != sk_function_parms)
4377 : : return NULL_TREE;
4378 : :
4379 : : /* Once we've tied off the original user-authored body in fn_body.
4380 : : Start the replacement synthesized ramp body. */
4381 : :
4382 : 1323 : tree body;
4383 : 1323 : if (use_eh_spec_block (fndecl))
4384 : : {
4385 : 390 : body = pop_stmt_list (TREE_OPERAND (current_eh_spec_block, 0));
4386 : 390 : TREE_OPERAND (current_eh_spec_block, 0) = push_stmt_list ();
4387 : : }
4388 : : else
4389 : : {
4390 : 933 : body = pop_stmt_list (DECL_SAVED_TREE (fndecl));
4391 : 933 : DECL_SAVED_TREE (fndecl) = push_stmt_list ();
4392 : : }
4393 : :
4394 : : /* We can't validly get here with an empty statement list, since there's no
4395 : : way for the FE to decide it's a coroutine in the absence of any code. */
4396 : 1323 : gcc_checking_assert (body != NULL_TREE);
4397 : :
4398 : : /* If we have an empty or erroneous function body, do not try to transform it
4399 : : since that would potentially wrap errors. */
4400 : 1323 : tree body_start = expr_first (body);
4401 : 1323 : if (body_start == NULL_TREE || body_start == error_mark_node)
4402 : : {
4403 : : /* Restore the original state. */
4404 : 21 : add_stmt (body);
4405 : 21 : return NULL_TREE;
4406 : : }
4407 : : return body;
4408 : : }
4409 : :
4410 : : /* Build the expression to allocate the coroutine frame according to the
4411 : : rules of [dcl.fct.def.coroutine] / 9. */
4412 : :
4413 : : static tree
4414 : 1301 : build_coroutine_frame_alloc_expr (tree promise_type, tree orig_fn_decl,
4415 : : location_t fn_start, tree grooaf,
4416 : : hash_map<tree, param_info> *param_uses,
4417 : : tree frame_size)
4418 : : {
4419 : : /* Allocate the frame, this has several possibilities:
4420 : : [dcl.fct.def.coroutine] / 9 (part 1)
4421 : : The allocation function’s name is looked up in the scope of the promise
4422 : : type. It is not a failure for it to be absent see part 4, below. */
4423 : :
4424 : 1301 : tree nwname = ovl_op_identifier (false, NEW_EXPR);
4425 : 1301 : tree new_fn_call = NULL_TREE;
4426 : 1301 : tree dummy_promise
4427 : 1301 : = build_dummy_object (get_coroutine_promise_type (orig_fn_decl));
4428 : :
4429 : 1301 : if (TYPE_HAS_NEW_OPERATOR (promise_type))
4430 : : {
4431 : 119 : tree fns = lookup_promise_method (orig_fn_decl, nwname, fn_start,
4432 : : /*musthave=*/true);
4433 : : /* [dcl.fct.def.coroutine] / 9 (part 2)
4434 : : If the lookup finds an allocation function in the scope of the promise
4435 : : type, overload resolution is performed on a function call created by
4436 : : assembling an argument list. The first argument is the amount of space
4437 : : requested, and has type std::size_t. The lvalues p1...pn are the
4438 : : succeeding arguments.. */
4439 : 119 : vec<tree, va_gc> *args = make_tree_vector ();
4440 : 119 : vec_safe_push (args, frame_size); /* Space needed. */
4441 : :
4442 : 189 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
4443 : 70 : arg = DECL_CHAIN (arg))
4444 : : {
4445 : 70 : param_info *parm_i = param_uses->get (arg);
4446 : 70 : gcc_checking_assert (parm_i);
4447 : 70 : if (parm_i->this_ptr || parm_i->lambda_cobj)
4448 : : {
4449 : : /* We pass a reference to *this to the allocator lookup. */
4450 : : /* It's unsafe to use the cp_ version here since current_class_ref
4451 : : might've gotten clobbered earlier during rewrite_param_uses. */
4452 : 2 : tree this_ref = build_fold_indirect_ref (arg);
4453 : 2 : vec_safe_push (args, this_ref);
4454 : 2 : }
4455 : : else
4456 : 68 : vec_safe_push (args, convert_from_reference (arg));
4457 : : }
4458 : :
4459 : : /* Note the function selected; we test to see if it's NOTHROW. */
4460 : 119 : tree func;
4461 : : /* Failure is not an error for this attempt. */
4462 : 119 : new_fn_call = build_new_method_call (dummy_promise, fns, &args, NULL,
4463 : : LOOKUP_NORMAL, &func, tf_none);
4464 : 119 : release_tree_vector (args);
4465 : :
4466 : 119 : if (new_fn_call == error_mark_node)
4467 : : {
4468 : : /* [dcl.fct.def.coroutine] / 9 (part 3)
4469 : : If no viable function is found, overload resolution is performed
4470 : : again on a function call created by passing just the amount of
4471 : : space required as an argument of type std::size_t. */
4472 : 49 : args = make_tree_vector_single (frame_size); /* Space needed. */
4473 : 49 : new_fn_call = build_new_method_call (dummy_promise, fns, &args,
4474 : : NULL_TREE, LOOKUP_NORMAL, &func,
4475 : : tf_none);
4476 : 49 : release_tree_vector (args);
4477 : : }
4478 : :
4479 : : /* However, if the promise provides an operator new, then one of these
4480 : : two options must be available. */
4481 : 119 : if (new_fn_call == error_mark_node)
4482 : : {
4483 : 1 : error_at (fn_start, "%qE is provided by %qT but is not usable with"
4484 : : " the function signature %qD", nwname, promise_type,
4485 : : orig_fn_decl);
4486 : 2 : return error_mark_node;
4487 : : }
4488 : 118 : else if (grooaf && !TYPE_NOTHROW_P (TREE_TYPE (func)))
4489 : : {
4490 : 1 : error_at (fn_start, "%qE is provided by %qT but %qE is not marked"
4491 : : " %<throw()%> or %<noexcept%>", grooaf, promise_type, nwname);
4492 : 1 : return error_mark_node;
4493 : : }
4494 : 117 : else if (!grooaf && TYPE_NOTHROW_P (TREE_TYPE (func)))
4495 : 1 : warning_at (fn_start, 0, "%qE is marked %<throw()%> or %<noexcept%> but"
4496 : : " no usable %<get_return_object_on_allocation_failure%>"
4497 : : " is provided by %qT", nwname, promise_type);
4498 : : }
4499 : : else /* No operator new in the promise. */
4500 : : {
4501 : : /* [dcl.fct.def.coroutine] / 9 (part 4)
4502 : : If this lookup fails, the allocation function’s name is looked up in
4503 : : the global scope. */
4504 : :
4505 : 1182 : vec<tree, va_gc> *args;
4506 : : /* build_operator_new_call () will insert size needed as element 0 of
4507 : : this, and we might need to append the std::nothrow constant. */
4508 : 1182 : vec_alloc (args, 2);
4509 : 1182 : if (grooaf)
4510 : : {
4511 : : /* [dcl.fct.def.coroutine] / 10 (part 2)
4512 : : If any declarations (of the get return on allocation fail) are
4513 : : found, then the result of a call to an allocation function used
4514 : : to obtain storage for the coroutine state is assumed to return
4515 : : nullptr if it fails to obtain storage and, if a global allocation
4516 : : function is selected, the ::operator new(size_t, nothrow_t) form
4517 : : is used. The allocation function used in this case shall have a
4518 : : non-throwing noexcept-specification. So we need std::nothrow. */
4519 : 10 : tree std_nt = lookup_qualified_name (std_node,
4520 : : get_identifier ("nothrow"),
4521 : : LOOK_want::NORMAL,
4522 : 10 : /*complain=*/true);
4523 : 10 : if (!std_nt || std_nt == error_mark_node)
4524 : : {
4525 : : /* Something is seriously wrong, punt. */
4526 : 1 : error_at (fn_start, "%qE is provided by %qT but %<std::nothrow%>"
4527 : : " cannot be found", grooaf, promise_type);
4528 : 1 : return error_mark_node;
4529 : : }
4530 : 9 : vec_safe_push (args, std_nt);
4531 : : }
4532 : :
4533 : : /* If we get to this point, we must succeed in looking up the global
4534 : : operator new for the params provided. Since we are not setting
4535 : : size_check or cookie, we expect frame_size to be unaltered. */
4536 : 1181 : tree cookie = NULL;
4537 : 1181 : new_fn_call = build_operator_new_call (nwname, &args, &frame_size,
4538 : : &cookie, /*align_arg=*/NULL,
4539 : : /*size_check=*/NULL, /*fn=*/NULL,
4540 : : tf_warning_or_error);
4541 : 1181 : release_tree_vector (args);
4542 : : }
4543 : : return new_fn_call;
4544 : : }
4545 : :
4546 : : /* Build an expression to delete the coroutine state frame. */
4547 : :
4548 : : static tree
4549 : 2590 : build_coroutine_frame_delete_expr (tree coro_fp, tree frame_size,
4550 : : tree promise_type, location_t loc)
4551 : : {
4552 : : /* Cast the frame pointer to a pointer to promise so that the build op
4553 : : delete call will search the promise. */
4554 : 2590 : tree pptr_type = build_pointer_type (promise_type);
4555 : 2590 : tree frame_arg = build1_loc (loc, CONVERT_EXPR, pptr_type, coro_fp);
4556 : : /* [dcl.fct.def.coroutine] / 12 sentence 3:
4557 : : If both a usual deallocation function with only a pointer parameter and
4558 : : a usual deallocation function with both a pointer parameter and a size
4559 : : parameter are found, then the selected deallocation function shall be the
4560 : : one with two parameters. */
4561 : 2590 : tree del_coro_fr
4562 : 2590 : = build_coroutine_op_delete_call (DELETE_EXPR, frame_arg, frame_size,
4563 : : /*global_p=*/false, /*placement=*/NULL,
4564 : : /*alloc_fn=*/NULL, tf_warning_or_error);
4565 : 2590 : if (!del_coro_fr || del_coro_fr == error_mark_node)
4566 : 1 : return error_mark_node;
4567 : : return del_coro_fr;
4568 : : }
4569 : :
4570 : : /* Build the ramp function.
4571 : : Here we take the original function definition which has now had its body
4572 : : removed, and use it as the declaration of the ramp which both replaces the
4573 : : user's written function at call sites, and is responsible for starting
4574 : : the coroutine it defined.
4575 : : returns NULL_TREE on error or an expression for the frame size.
4576 : :
4577 : : We should arrive here with the state of the compiler as if we had just
4578 : : executed start_preparsed_function(). */
4579 : :
4580 : : bool
4581 : 1302 : cp_coroutine_transform::build_ramp_function ()
4582 : : {
4583 : 1302 : gcc_checking_assert (current_binding_level
4584 : : && current_binding_level->kind == sk_function_parms);
4585 : :
4586 : : /* This is completely synthetic code, if we find an issue then we have not
4587 : : much chance to point at the most useful place in the user's code. In
4588 : : lieu of this use the function start - so at least the diagnostic relates
4589 : : to something that the user can inspect. */
4590 : 1302 : iloc_sentinel saved_position (fn_start);
4591 : 1302 : location_t loc = fn_start;
4592 : :
4593 : 1302 : tree promise_type = get_coroutine_promise_type (orig_fn_decl);
4594 : 1302 : tree fn_return_type = TREE_TYPE (TREE_TYPE (orig_fn_decl));
4595 : 1302 : bool void_ramp_p = VOID_TYPE_P (fn_return_type);
4596 : : /* We know there was no return statement, that is intentional. */
4597 : 1302 : suppress_warning (orig_fn_decl, OPT_Wreturn_type);
4598 : :
4599 : : /* [dcl.fct.def.coroutine] / 10 (part1)
4600 : : The unqualified-id get_return_object_on_allocation_failure is looked up
4601 : : in the scope of the promise type by class member access lookup. */
4602 : :
4603 : : /* We don't require this, but, if the lookup succeeds, then the function
4604 : : must be usable, punt if it is not. */
4605 : 1302 : tree grooaf_meth
4606 : 1302 : = lookup_promise_method (orig_fn_decl,
4607 : : coro_gro_on_allocation_fail_identifier, loc,
4608 : : /*musthave*/ false);
4609 : 1302 : tree grooaf = NULL_TREE;
4610 : 1302 : tree dummy_promise
4611 : 2604 : = build_dummy_object (get_coroutine_promise_type (orig_fn_decl));
4612 : 1302 : if (grooaf_meth && grooaf_meth != error_mark_node)
4613 : : {
4614 : 30 : grooaf
4615 : 30 : = coro_build_promise_expression (orig_fn_decl, dummy_promise,
4616 : : coro_gro_on_allocation_fail_identifier,
4617 : : fn_start, NULL, /*musthave=*/false);
4618 : :
4619 : : /* That should succeed. */
4620 : 30 : if (!grooaf || grooaf == error_mark_node)
4621 : : {
4622 : 1 : error_at (fn_start, "%qE is provided by %qT but is not usable with"
4623 : : " the function %qD", coro_gro_on_allocation_fail_identifier,
4624 : : promise_type, orig_fn_decl);
4625 : 1 : return false;
4626 : : }
4627 : : }
4628 : :
4629 : : /* Check early for usable allocator/deallocator, without which we cannot
4630 : : build a useful ramp; early exit if they are not available or usable. */
4631 : :
4632 : 1301 : frame_size = TYPE_SIZE_UNIT (frame_type);
4633 : :
4634 : : /* Make a var to represent the frame pointer early. Initialize to zero so
4635 : : that we can pass it to the IFN_CO_FRAME (to give that access to the frame
4636 : : type). */
4637 : 1301 : tree coro_fp = coro_build_artificial_var (loc, "_Coro_frameptr",
4638 : : frame_ptr_type, orig_fn_decl,
4639 : : NULL_TREE);
4640 : :
4641 : 1301 : tree new_fn_call
4642 : 1301 : = build_coroutine_frame_alloc_expr (promise_type, orig_fn_decl, fn_start,
4643 : : grooaf, ¶m_uses, frame_size);
4644 : :
4645 : : /* We must have a useable allocator to proceed. */
4646 : 1301 : if (!new_fn_call || new_fn_call == error_mark_node)
4647 : : return false;
4648 : :
4649 : : /* Likewise, we need the DTOR to delete the frame. */
4650 : 1298 : tree delete_frame_call
4651 : 1298 : = build_coroutine_frame_delete_expr (coro_fp, frame_size, promise_type,
4652 : : fn_start);
4653 : 1298 : if (!delete_frame_call || delete_frame_call == error_mark_node)
4654 : : return false;
4655 : :
4656 : : /* At least verify we can lookup the get return object method. */
4657 : 1297 : tree get_ro_meth
4658 : 1297 : = lookup_promise_method (orig_fn_decl,
4659 : : coro_get_return_object_identifier, loc,
4660 : : /*musthave*/ true);
4661 : 1297 : if (!get_ro_meth || get_ro_meth == error_mark_node)
4662 : : return false;
4663 : :
4664 : : /* So now construct the Ramp: */
4665 : :
4666 : 1296 : tree ramp_fnbody = begin_function_body ();
4667 : : /* Now build the ramp function pieces. */
4668 : 1296 : tree ramp_bind = build3 (BIND_EXPR, void_type_node, NULL, NULL, NULL);
4669 : 1296 : add_stmt (ramp_bind);
4670 : 1296 : tree ramp_outer_bind = push_stmt_list ();
4671 : 1296 : tree varlist = coro_fp;
4672 : :
4673 : : /* To signal that we need to cleanup copied function args. */
4674 : 1296 : if (flag_exceptions && DECL_ARGUMENTS (orig_fn_decl))
4675 : 1485 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
4676 : 838 : arg = DECL_CHAIN (arg))
4677 : : {
4678 : 838 : param_info *parm_i = param_uses.get (arg);
4679 : 838 : gcc_checking_assert (parm_i);
4680 : 838 : if (parm_i->trivial_dtor)
4681 : 758 : continue;
4682 : 80 : DECL_CHAIN (parm_i->guard_var) = varlist;
4683 : 80 : varlist = parm_i->guard_var;
4684 : : }
4685 : :
4686 : : /* Signal that we need to clean up the promise object on exception. */
4687 : 1296 : tree coro_promise_live
4688 : 1296 : = coro_build_artificial_var (loc, "_Coro_promise_live", boolean_type_node,
4689 : : orig_fn_decl, boolean_false_node);
4690 : 1296 : DECL_CHAIN (coro_promise_live) = varlist;
4691 : 1296 : varlist = coro_promise_live;
4692 : :
4693 : : /* When the get-return-object is in the RETURN slot, we need to arrange for
4694 : : cleanup on exception. */
4695 : 1296 : tree coro_gro_live
4696 : 1296 : = coro_build_artificial_var (loc, "_Coro_gro_live", boolean_type_node,
4697 : : orig_fn_decl, boolean_false_node);
4698 : :
4699 : 1296 : DECL_CHAIN (coro_gro_live) = varlist;
4700 : 1296 : varlist = coro_gro_live;
4701 : :
4702 : : /* Collected the scope vars we need ... only one for now. */
4703 : 1296 : BIND_EXPR_VARS (ramp_bind) = nreverse (varlist);
4704 : :
4705 : : /* We're now going to create a new top level scope block for the ramp
4706 : : function. */
4707 : 1296 : tree top_block = make_node (BLOCK);
4708 : :
4709 : 1296 : BIND_EXPR_BLOCK (ramp_bind) = top_block;
4710 : 1296 : BLOCK_VARS (top_block) = BIND_EXPR_VARS (ramp_bind);
4711 : 1296 : BLOCK_SUBBLOCKS (top_block) = NULL_TREE;
4712 : 1296 : current_binding_level->blocks = top_block;
4713 : :
4714 : 1296 : add_decl_expr (coro_fp);
4715 : 1296 : if (flag_exceptions && DECL_ARGUMENTS (orig_fn_decl))
4716 : 1485 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
4717 : 838 : arg = DECL_CHAIN (arg))
4718 : : {
4719 : 838 : param_info *parm_i = param_uses.get (arg);
4720 : 838 : if (parm_i->trivial_dtor)
4721 : 758 : continue;
4722 : 80 : add_decl_expr (parm_i->guard_var);
4723 : : }
4724 : 1296 : add_decl_expr (coro_promise_live);
4725 : 1296 : add_decl_expr (coro_gro_live);
4726 : :
4727 : : /* Build the frame. */
4728 : :
4729 : : /* The CO_FRAME internal function is a mechanism to allow the middle end
4730 : : to adjust the allocation in response to optimizations. We provide the
4731 : : current conservative estimate of the frame size (as per the current)
4732 : : computed layout. */
4733 : :
4734 : 1296 : tree resizeable
4735 : 1296 : = build_call_expr_internal_loc (loc, IFN_CO_FRAME, size_type_node, 2,
4736 : : frame_size,
4737 : : build_zero_cst (frame_ptr_type));
4738 : 1296 : CALL_EXPR_ARG (new_fn_call, 0) = resizeable;
4739 : 1296 : tree allocated = build1 (CONVERT_EXPR, frame_ptr_type, new_fn_call);
4740 : 1296 : tree r = cp_build_init_expr (coro_fp, allocated);
4741 : 1296 : finish_expr_stmt (r);
4742 : :
4743 : : /* If the user provided a method to return an object on alloc fail, then
4744 : : check the returned pointer and call the func if it's null.
4745 : : Otherwise, no check, and we fail for noexcept/fno-exceptions cases. */
4746 : :
4747 : 1296 : if (grooaf)
4748 : : {
4749 : : /* [dcl.fct.def.coroutine] / 10 (part 3)
4750 : : If the allocation function returns nullptr,the coroutine returns
4751 : : control to the caller of the coroutine and the return value is
4752 : : obtained by a call to T::get_return_object_on_allocation_failure(),
4753 : : where T is the promise type. */
4754 : 27 : tree if_stmt = begin_if_stmt ();
4755 : 27 : tree cond = build1 (CONVERT_EXPR, frame_ptr_type, nullptr_node);
4756 : 27 : cond = build2 (EQ_EXPR, boolean_type_node, coro_fp, cond);
4757 : 27 : finish_if_stmt_cond (cond, if_stmt);
4758 : 27 : r = NULL_TREE;
4759 : 27 : if (void_ramp_p)
4760 : : /* Execute the get-return-object-on-alloc-fail call... */
4761 : 0 : finish_expr_stmt (grooaf);
4762 : : else
4763 : : /* Get the fallback return object. */
4764 : : r = grooaf;
4765 : 27 : finish_return_stmt (r);
4766 : 27 : finish_then_clause (if_stmt);
4767 : 27 : finish_if_stmt (if_stmt);
4768 : : }
4769 : :
4770 : : /* Up to now any exception thrown will propagate directly to the caller.
4771 : : This is OK since the only source of such exceptions would be in allocation
4772 : : of the coroutine frame, and therefore the ramp will not have initialized
4773 : : any further state. From here, we will track state that needs explicit
4774 : : destruction in the case that promise or g.r.o setup fails or an exception
4775 : : is thrown from the initial suspend expression. */
4776 : 1296 : tree ramp_cleanup = NULL_TREE;
4777 : 1296 : if (flag_exceptions)
4778 : : {
4779 : 1289 : ramp_cleanup = build_stmt (loc, TRY_BLOCK, NULL, NULL);
4780 : 1289 : add_stmt (ramp_cleanup);
4781 : 1289 : TRY_STMTS (ramp_cleanup) = push_stmt_list ();
4782 : : }
4783 : :
4784 : : /* deref the frame pointer, to use in member access code. */
4785 : 1296 : tree deref_fp = build_x_arrow (loc, coro_fp, tf_warning_or_error);
4786 : :
4787 : : /* For now, once allocation has succeeded we always assume that this needs
4788 : : destruction, there's no impl. for frame allocation elision. */
4789 : 1296 : tree fnf_m = lookup_member (frame_type, coro_frame_needs_free_id,
4790 : : 1, 0,tf_warning_or_error);
4791 : 1296 : tree fnf_x = build_class_member_access_expr (deref_fp, fnf_m, NULL_TREE,
4792 : : false, tf_warning_or_error);
4793 : 1296 : r = cp_build_init_expr (fnf_x, boolean_true_node);
4794 : 1296 : finish_expr_stmt (r);
4795 : :
4796 : : /* Put the resumer and destroyer functions in. */
4797 : :
4798 : 1296 : tree actor_addr = build1 (ADDR_EXPR, act_des_fn_ptr_type, resumer);
4799 : 1296 : tree resume_m
4800 : 1296 : = lookup_member (frame_type, coro_resume_fn_id,
4801 : : /*protect=*/1, /*want_type=*/0, tf_warning_or_error);
4802 : 1296 : tree resume_x = build_class_member_access_expr (deref_fp, resume_m, NULL_TREE,
4803 : : false, tf_warning_or_error);
4804 : 1296 : r = cp_build_init_expr (loc, resume_x, actor_addr);
4805 : 1296 : finish_expr_stmt (r);
4806 : :
4807 : 1296 : tree destroy_addr = build1 (ADDR_EXPR, act_des_fn_ptr_type, destroyer);
4808 : 1296 : tree destroy_m
4809 : 1296 : = lookup_member (frame_type, coro_destroy_fn_id,
4810 : : /*protect=*/1, /*want_type=*/0, tf_warning_or_error);
4811 : 1296 : tree destroy_x
4812 : 1296 : = build_class_member_access_expr (deref_fp, destroy_m, NULL_TREE, false,
4813 : : tf_warning_or_error);
4814 : 1296 : r = cp_build_init_expr (loc, destroy_x, destroy_addr);
4815 : 1296 : finish_expr_stmt (r);
4816 : :
4817 : : /* [dcl.fct.def.coroutine] /13
4818 : : When a coroutine is invoked, a copy is created for each coroutine
4819 : : parameter. Each such copy is an object with automatic storage duration
4820 : : that is direct-initialized from an lvalue referring to the corresponding
4821 : : parameter if the parameter is an lvalue reference, and from an xvalue
4822 : : referring to it otherwise. A reference to a parameter in the function-
4823 : : body of the coroutine and in the call to the coroutine promise
4824 : : constructor is replaced by a reference to its copy. */
4825 : :
4826 : 1296 : vec<tree, va_gc> *promise_args = NULL; /* So that we can adjust refs. */
4827 : :
4828 : : /* The initialization and destruction of each parameter copy occurs in the
4829 : : context of the called coroutine. Initializations of parameter copies are
4830 : : sequenced before the call to the coroutine promise constructor and
4831 : : indeterminately sequenced with respect to each other. The lifetime of
4832 : : parameter copies ends immediately after the lifetime of the coroutine
4833 : : promise object ends. */
4834 : :
4835 : 1296 : if (DECL_ARGUMENTS (orig_fn_decl))
4836 : : {
4837 : 648 : promise_args = make_tree_vector ();
4838 : 1487 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
4839 : 839 : arg = DECL_CHAIN (arg))
4840 : : {
4841 : 839 : bool existed;
4842 : 839 : param_info &parm = param_uses.get_or_insert (arg, &existed);
4843 : 839 : tree fld_idx
4844 : 839 : = coro_build_frame_access_expr (deref_fp, parm.field_id,
4845 : 839 : false, tf_warning_or_error);
4846 : :
4847 : : /* Add this to the promise CTOR arguments list, accounting for
4848 : : refs and special handling for method this ptr. */
4849 : 839 : if (parm.this_ptr || parm.lambda_cobj)
4850 : : {
4851 : : /* We pass a reference to *this to the param preview. */
4852 : : /* It's unsafe to use the cp_ version here since current_class_ref
4853 : : might've gotten clobbered earlier during rewrite_param_uses. */
4854 : 209 : tree this_ref = build_fold_indirect_ref (arg);
4855 : 209 : vec_safe_push (promise_args, this_ref);
4856 : 209 : }
4857 : 630 : else if (parm.rv_ref)
4858 : 32 : vec_safe_push (promise_args, move (fld_idx));
4859 : : else
4860 : 598 : vec_safe_push (promise_args, fld_idx);
4861 : :
4862 : 839 : if (parm.rv_ref || parm.pt_ref)
4863 : : /* Initialise the frame reference field directly. */
4864 : 108 : r = cp_build_modify_expr (loc, TREE_OPERAND (fld_idx, 0),
4865 : : INIT_EXPR, arg, tf_warning_or_error);
4866 : : else
4867 : : {
4868 : 731 : r = forward_parm (arg);
4869 : 731 : r = cp_build_modify_expr (loc, fld_idx, INIT_EXPR, r,
4870 : : tf_warning_or_error);
4871 : : }
4872 : 839 : finish_expr_stmt (r);
4873 : 839 : if (!parm.trivial_dtor)
4874 : : {
4875 : 81 : param_dtor_list.safe_push (parm.field_id);
4876 : : /* Cleanup this frame copy on exception. */
4877 : 81 : parm.fr_copy_dtor
4878 : 81 : = cxx_maybe_build_cleanup (fld_idx, tf_warning_or_error);
4879 : 81 : if (flag_exceptions)
4880 : : {
4881 : : /* This var is now live. */
4882 : 80 : r = build_modify_expr (loc, parm.guard_var,
4883 : : boolean_type_node, INIT_EXPR, loc,
4884 : : boolean_true_node, boolean_type_node);
4885 : 80 : finish_expr_stmt (r);
4886 : : }
4887 : : }
4888 : : }
4889 : : }
4890 : :
4891 : : /* Set up the promise. */
4892 : 1296 : tree promise_m
4893 : 1296 : = lookup_member (frame_type, coro_promise_id,
4894 : : /*protect=*/1, /*want_type=*/0, tf_warning_or_error);
4895 : :
4896 : 1296 : tree p = build_class_member_access_expr (deref_fp, promise_m, NULL_TREE,
4897 : : false, tf_warning_or_error);
4898 : :
4899 : 1296 : if (type_build_ctor_call (promise_type))
4900 : : {
4901 : : /* Construct the promise object [dcl.fct.def.coroutine] / 5.7.
4902 : :
4903 : : First try to find a constructor with an argument list comprised of
4904 : : the parameter copies. */
4905 : :
4906 : 1000 : if (DECL_ARGUMENTS (orig_fn_decl))
4907 : : {
4908 : 572 : r = build_special_member_call (p, complete_ctor_identifier,
4909 : : &promise_args, promise_type,
4910 : : LOOKUP_NORMAL, tf_none);
4911 : 572 : release_tree_vector (promise_args);
4912 : : }
4913 : : else
4914 : : r = NULL_TREE;
4915 : :
4916 : : /* If that fails then the promise constructor argument list is empty. */
4917 : 572 : if (r == NULL_TREE || r == error_mark_node)
4918 : 737 : r = build_special_member_call (p, complete_ctor_identifier, NULL,
4919 : : promise_type, LOOKUP_NORMAL,
4920 : : tf_warning_or_error);
4921 : :
4922 : : /* If type_build_ctor_call() encounters deprecated implicit CTORs it will
4923 : : return true, and therefore we will execute this code path. However,
4924 : : we might well not actually require a CTOR and under those conditions
4925 : : the build call above will not return a call expression, but the
4926 : : original instance object. Do not attempt to add the statement unless
4927 : : it has side-effects. */
4928 : 1000 : if (r && r != error_mark_node && TREE_SIDE_EFFECTS (r))
4929 : 992 : finish_expr_stmt (r);
4930 : : }
4931 : :
4932 : 1296 : tree promise_dtor = cxx_maybe_build_cleanup (p, tf_warning_or_error);;
4933 : 1296 : if (flag_exceptions && promise_dtor)
4934 : : {
4935 : 955 : r = cp_build_init_expr (coro_promise_live, boolean_true_node);
4936 : 955 : finish_expr_stmt (r);
4937 : : }
4938 : :
4939 : 1296 : tree get_ro
4940 : 1296 : = coro_build_promise_expression (orig_fn_decl, p,
4941 : : coro_get_return_object_identifier,
4942 : : fn_start, NULL, /*musthave=*/true);
4943 : :
4944 : : /* Without a return object we haven't got much clue what's going on. */
4945 : 1296 : if (!get_ro || get_ro == error_mark_node)
4946 : : {
4947 : 0 : BIND_EXPR_BODY (ramp_bind) = pop_stmt_list (ramp_outer_bind);
4948 : 0 : return false;
4949 : : }
4950 : :
4951 : : /* Check for a bad get return object type.
4952 : : [dcl.fct.def.coroutine] / 7 requires:
4953 : : The expression promise.get_return_object() is used to initialize the
4954 : : returned reference or prvalue result object ... */
4955 : 1296 : tree gro_type = TREE_TYPE (get_ro);
4956 : 1296 : if (VOID_TYPE_P (gro_type) && !void_ramp_p)
4957 : : {
4958 : 1 : error_at (fn_start, "no viable conversion from %<void%> provided by"
4959 : : " %<get_return_object%> to return type %qT", fn_return_type);
4960 : 1 : return false;
4961 : : }
4962 : :
4963 : : /* Initialize the resume_idx_var to 0, meaning "not started". */
4964 : 1295 : tree resume_idx_m
4965 : 1295 : = lookup_member (frame_type, coro_resume_index_id,
4966 : : /*protect=*/1, /*want_type=*/0, tf_warning_or_error);
4967 : 1295 : tree resume_idx
4968 : 1295 : = build_class_member_access_expr (deref_fp, resume_idx_m, NULL_TREE, false,
4969 : : tf_warning_or_error);
4970 : 1295 : r = build_int_cst (short_unsigned_type_node, 0);
4971 : 1295 : r = cp_build_init_expr (loc, resume_idx, r);
4972 : 1295 : finish_expr_stmt (r);
4973 : :
4974 : : /* Used for return objects in the RESULT slot. */
4975 : 1295 : tree ret_val_dtor = NULL_TREE;
4976 : :
4977 : : /* [dcl.fct.def.coroutine] / 7
4978 : : The expression promise.get_return_object() is used to initialize the
4979 : : glvalue result or prvalue result object of a call to a coroutine. */
4980 : :
4981 : : /* We must manage the cleanups ourselves, because the responsibility for
4982 : : them changes after the initial suspend. However, any use of
4983 : : cxx_maybe_build_cleanup () can set the throwing_cleanup flag. */
4984 : 1295 : cp_function_chain->throwing_cleanup = false;
4985 : 1295 : if (void_ramp_p)
4986 : : /* We still want to call the method, even if the result is unused. */
4987 : : r = get_ro;
4988 : : else
4989 : : {
4990 : : /* The initial section of finish_return_expr (). */
4991 : 1279 : bool no_warning;
4992 : 1279 : bool dangling;
4993 : : /* Without a relevant location, bad conversions in check_return_expr
4994 : : result in unusable diagnostics, since there is not even a mention
4995 : : of the relevant function. Here we carry out the first part of
4996 : : finish_return_expr(). */
4997 : 1279 : input_location = fn_start;
4998 : 1279 : r = check_return_expr (get_ro, &no_warning, &dangling);
4999 : 1279 : input_location = UNKNOWN_LOCATION;
5000 : 1279 : gcc_checking_assert (!dangling);
5001 : : /* Check for bad things. */
5002 : 1279 : if (!r || r == error_mark_node)
5003 : 3 : return false;
5004 : : }
5005 : :
5006 : 1292 : finish_expr_stmt (r);
5007 : :
5008 : 1292 : if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (fn_return_type))
5009 : : /* If some part of the initalization code (prior to the await_resume
5010 : : of the initial suspend expression), then we need to clean up the
5011 : : return value. */
5012 : 1029 : ret_val_dtor = cxx_maybe_build_cleanup (DECL_RESULT (orig_fn_decl),
5013 : : tf_warning_or_error);
5014 : :
5015 : : /* If we have a live g.r.o in the return slot, then signal this for exception
5016 : : cleanup. */
5017 : 1029 : if (ret_val_dtor)
5018 : : {
5019 : 1029 : r = build_modify_expr (loc, coro_gro_live, boolean_type_node,
5020 : : INIT_EXPR, loc, boolean_true_node,
5021 : : boolean_type_node);
5022 : 1029 : finish_expr_stmt (r);
5023 : : }
5024 : :
5025 : : /* Start the coroutine body. */
5026 : 1292 : r = build_call_expr_loc (fn_start, resumer, 1, coro_fp);
5027 : 1292 : finish_expr_stmt (r);
5028 : :
5029 : : /* The ramp is done, we just need the return statement, which we build from
5030 : : the return object we constructed before we called the actor. */
5031 : :
5032 : 1292 : r = void_ramp_p ? NULL_TREE : DECL_RESULT (orig_fn_decl);
5033 : :
5034 : : /* The reminder of finish_return_expr (). */
5035 : 1292 : r = build_stmt (loc, RETURN_EXPR, r);
5036 : 1292 : r = maybe_cleanup_point_expr_void (r);
5037 : 1292 : r = add_stmt (r);
5038 : :
5039 : 1292 : if (flag_exceptions)
5040 : : {
5041 : 1285 : TRY_HANDLERS (ramp_cleanup) = push_stmt_list ();
5042 : 1285 : tree handler = begin_handler ();
5043 : 1285 : finish_handler_parms (NULL_TREE, handler); /* catch (...) */
5044 : :
5045 : : /* If we have a live G.R.O in the return slot, then run its DTOR. */
5046 : 1285 : if (ret_val_dtor && ret_val_dtor != error_mark_node)
5047 : : {
5048 : 1029 : tree gro_d_if = begin_if_stmt ();
5049 : 1029 : finish_if_stmt_cond (coro_gro_live, gro_d_if);
5050 : 1029 : finish_expr_stmt (ret_val_dtor);
5051 : 1029 : finish_then_clause (gro_d_if);
5052 : 1029 : finish_if_stmt (gro_d_if);
5053 : : }
5054 : :
5055 : : /* Before initial resume is called, the responsibility for cleanup on
5056 : : exception falls to the ramp. After that, the coroutine body code
5057 : : should do the cleanup. */
5058 : 1285 : tree iarc_m = lookup_member (frame_type, coro_frame_i_a_r_c_id,
5059 : : 1, 0, tf_warning_or_error);
5060 : 1285 : tree iarc_x
5061 : 1285 : = build_class_member_access_expr (deref_fp, iarc_m, NULL_TREE,
5062 : : /*preserve_reference*/false,
5063 : : tf_warning_or_error);
5064 : 1285 : tree not_iarc
5065 : 1285 : = build1_loc (loc, TRUTH_NOT_EXPR, boolean_type_node, iarc_x);
5066 : 1285 : tree cleanup_if = begin_if_stmt ();
5067 : 1285 : finish_if_stmt_cond (not_iarc, cleanup_if);
5068 : : /* If the promise is live, then run its dtor if that's available. */
5069 : 1285 : if (promise_dtor && promise_dtor != error_mark_node)
5070 : : {
5071 : 952 : tree promise_d_if = begin_if_stmt ();
5072 : 952 : finish_if_stmt_cond (coro_promise_live, promise_d_if);
5073 : 952 : finish_expr_stmt (promise_dtor);
5074 : 952 : finish_then_clause (promise_d_if);
5075 : 952 : finish_if_stmt (promise_d_if);
5076 : : }
5077 : :
5078 : : /* Clean up any frame copies of parms with non-trivial dtors.
5079 : : Do this in reverse order from their creation. */
5080 : 1285 : auto_vec<param_info *> worklist;
5081 : 1285 : if (DECL_ARGUMENTS (orig_fn_decl))
5082 : 1481 : for (tree arg = DECL_ARGUMENTS (orig_fn_decl); arg != NULL;
5083 : 836 : arg = DECL_CHAIN (arg))
5084 : : {
5085 : 836 : param_info *parm_i = param_uses.get (arg);
5086 : 836 : if (parm_i->trivial_dtor)
5087 : 756 : continue;
5088 : 80 : worklist.safe_push (parm_i);
5089 : : }
5090 : 1365 : while (!worklist.is_empty ())
5091 : : {
5092 : 80 : param_info *parm_i = worklist.pop ();
5093 : 80 : if (parm_i->fr_copy_dtor && parm_i->fr_copy_dtor != error_mark_node)
5094 : : {
5095 : 80 : tree dtor_if = begin_if_stmt ();
5096 : 80 : finish_if_stmt_cond (parm_i->guard_var, dtor_if);
5097 : 80 : finish_expr_stmt (parm_i->fr_copy_dtor);
5098 : 80 : finish_then_clause (dtor_if);
5099 : 80 : finish_if_stmt (dtor_if);
5100 : : }
5101 : : }
5102 : :
5103 : : /* No delete the frame if required. */
5104 : 1285 : tree fnf_if = begin_if_stmt ();
5105 : 1285 : finish_if_stmt_cond (fnf_x, fnf_if);
5106 : 1285 : finish_expr_stmt (delete_frame_call);
5107 : 1285 : finish_then_clause (fnf_if);
5108 : 1285 : finish_if_stmt (fnf_if);
5109 : :
5110 : : /* Finished cleanups conditional on "initial resume is not called". */
5111 : 1285 : finish_then_clause (cleanup_if);
5112 : 1285 : finish_if_stmt (cleanup_if);
5113 : :
5114 : 1285 : tree rethrow = build_throw (loc, NULL_TREE, tf_warning_or_error);
5115 : 1285 : suppress_warning (rethrow);
5116 : 1285 : finish_expr_stmt (rethrow);
5117 : 1285 : finish_handler (handler);
5118 : 1285 : TRY_HANDLERS (ramp_cleanup) = pop_stmt_list (TRY_HANDLERS (ramp_cleanup));
5119 : 1285 : }
5120 : :
5121 : 1292 : BIND_EXPR_BODY (ramp_bind) = pop_stmt_list (ramp_outer_bind);
5122 : 1292 : finish_function_body (ramp_fnbody);
5123 : 1292 : return true;
5124 : 1302 : }
5125 : :
5126 : : /* ------- Encapsulate analysis of the couroutine -------- */
5127 : :
5128 : :
5129 : 1323 : cp_coroutine_transform::cp_coroutine_transform (tree _orig_fn, bool _inl)
5130 : 1323 : : orig_fn_decl (_orig_fn), inline_p (_inl)
5131 : : {
5132 : : /* We don't expect to be called with missing decl or e_m_n. */
5133 : 1323 : gcc_checking_assert (orig_fn_decl
5134 : : && TREE_CODE (orig_fn_decl) == FUNCTION_DECL);
5135 : 1323 : if (!coro_function_valid_p (orig_fn_decl))
5136 : : {
5137 : : /* For early errors, we do not want a diagnostic about the missing
5138 : : ramp return value, since the user cannot fix this - a 'return' is
5139 : : not allowed in a coroutine. */
5140 : 20 : suppress_warning (orig_fn_decl, OPT_Wreturn_type);
5141 : : /* Discard the body, we can't process it further... */
5142 : 20 : pop_stmt_list (DECL_SAVED_TREE (orig_fn_decl));
5143 : : /* ... and make an empty fn. */
5144 : 20 : DECL_SAVED_TREE (orig_fn_decl) = push_stmt_list ();
5145 : : /* Match the expected nesting when an eh block is in use. */
5146 : 20 : if (use_eh_spec_block (orig_fn_decl))
5147 : 0 : current_eh_spec_block = begin_eh_spec_block ();
5148 : 20 : valid_coroutine = false;
5149 : : }
5150 : :
5151 : : /* We don't have the locus of the opening brace - it's filled in later (and
5152 : : there doesn't really seem to be any easy way to get at it).
5153 : : The closing brace is assumed to be input_location. */
5154 : 1323 : fn_start = DECL_SOURCE_LOCATION (orig_fn_decl);
5155 : :
5156 : : /* Build types we need. */
5157 : 1323 : tree fr_name = get_fn_local_identifier (orig_fn_decl, "Frame");
5158 : 1323 : frame_type = xref_tag (record_type, fr_name);
5159 : 1323 : DECL_CONTEXT (TYPE_NAME (frame_type)) = DECL_CONTEXT (orig_fn_decl);
5160 : 1323 : frame_ptr_type = build_pointer_type (frame_type);
5161 : 1323 : act_des_fn_type
5162 : 1323 : = build_function_type_list (void_type_node, frame_ptr_type, NULL_TREE);
5163 : 1323 : act_des_fn_ptr_type = build_pointer_type (act_des_fn_type);
5164 : 1323 : valid_coroutine = true;
5165 : 1323 : }
5166 : :
5167 : 1323 : cp_coroutine_transform::~cp_coroutine_transform ()
5168 : : {
5169 : 1323 : }
5170 : :
5171 : : /* Here we:
5172 : : a) Check that the function and promise type are valid for a
5173 : : coroutine.
5174 : : b) Carry out the initial morph to create the skeleton of the
5175 : : coroutine ramp function and the rewritten body.
5176 : :
5177 : : Assumptions.
5178 : :
5179 : : 1. We only hit this code once all dependencies are resolved.
5180 : : 2. The function body will be either a bind expr or a statement list
5181 : : 3. That cfun and current_function_decl are valid for the case we're
5182 : : expanding.
5183 : : 4. 'input_location' will be of the final brace for the function.
5184 : :
5185 : : We do something like this:
5186 : : declare a dummy coro frame.
5187 : : struct _R_frame {
5188 : : using handle_type = coro::coroutine_handle<coro1::promise_type>;
5189 : : void (*_Coro_resume_fn)(_R_frame *);
5190 : : void (*_Coro_destroy_fn)(_R_frame *);
5191 : : coro1::promise_type _Coro_promise;
5192 : : bool _Coro_frame_needs_free; free the coro frame mem if set.
5193 : : bool _Coro_i_a_r_c; [dcl.fct.def.coroutine] / 5.3
5194 : : short _Coro_resume_index;
5195 : : handle_type _Coro_self_handle;
5196 : : parameter copies (were required).
5197 : : local variables saved (including awaitables)
5198 : : (maybe) trailing space.
5199 : : }; */
5200 : :
5201 : : void
5202 : 1323 : cp_coroutine_transform::apply_transforms ()
5203 : : {
5204 : :
5205 : 1323 : coroutine_body
5206 : 1323 : = split_coroutine_body_from_ramp (orig_fn_decl);
5207 : 1323 : if (!coroutine_body)
5208 : : {
5209 : 21 : valid_coroutine = false;
5210 : 21 : return;
5211 : : }
5212 : : /* Keep the original function block tree to one side and reset. */
5213 : 1302 : body_blocks = current_binding_level->blocks;
5214 : 1302 : current_binding_level->blocks = NULL_TREE;
5215 : :
5216 : : /* Collect information on the original function params and their use in the
5217 : : function body. */
5218 : 1302 : analyze_fn_parms (orig_fn_decl, ¶m_uses);
5219 : :
5220 : : /* Declare the actor and destroyer functions, the following code needs to
5221 : : see these. */
5222 : 1302 : resumer
5223 : 1302 : = coro_build_actor_or_destroy_function (orig_fn_decl, act_des_fn_type,
5224 : : frame_ptr_type, true);
5225 : 1302 : destroyer
5226 : 1302 : = coro_build_actor_or_destroy_function (orig_fn_decl, act_des_fn_type,
5227 : : frame_ptr_type, false);
5228 : :
5229 : : /* Transform the function body as per [dcl.fct.def.coroutine] / 5. */
5230 : 1302 : wrap_original_function_body ();
5231 : :
5232 : : /* Analyze the body await expressions. */
5233 : 1302 : susp_frame_data body_aw_points (fs_label, &suspend_points);
5234 : 1302 : cp_walk_tree (&coroutine_body, await_statement_walker, &body_aw_points, NULL);
5235 : 1302 : await_count = body_aw_points.await_number;
5236 : :
5237 : : /* Determine the fields for the coroutine state. */
5238 : 1302 : tree field_list = NULL_TREE;
5239 : 1302 : local_vars_frame_data local_vars_data (&field_list, &local_var_uses);
5240 : 1302 : cp_walk_tree (&coroutine_body, register_local_var_uses, &local_vars_data, NULL);
5241 : :
5242 : : /* Conservative computation of the coroutine frame content. */
5243 : 1302 : frame_type = begin_class_definition (frame_type);
5244 : 1302 : TYPE_FIELDS (frame_type) = field_list;
5245 : 1302 : TYPE_BINFO (frame_type) = make_tree_binfo (0);
5246 : 1302 : BINFO_OFFSET (TYPE_BINFO (frame_type)) = size_zero_node;
5247 : 1302 : BINFO_TYPE (TYPE_BINFO (frame_type)) = frame_type;
5248 : 1302 : frame_type = finish_struct (frame_type, NULL_TREE);
5249 : :
5250 : 1302 : valid_coroutine = build_ramp_function ();
5251 : : }
5252 : :
5253 : : /* Having analysed and collected the necessary data we are now in a position
5254 : : to build the outlined coroutine body and the destroyer shim. */
5255 : :
5256 : : void
5257 : 1292 : cp_coroutine_transform::finish_transforms ()
5258 : : {
5259 : 1292 : if (!valid_coroutine)
5260 : : return;
5261 : :
5262 : 1292 : current_function_decl = resumer;
5263 : 1292 : build_actor_fn (fn_start, frame_type, resumer, coroutine_body, orig_fn_decl,
5264 : : &local_var_uses, &suspend_points, ¶m_dtor_list,
5265 : 1292 : resume_idx_var, await_count, frame_size, inline_p);
5266 : :
5267 : 1292 : current_function_decl = destroyer;
5268 : 1292 : build_destroy_fn (fn_start, frame_type, destroyer, resumer, inline_p);
5269 : : }
5270 : :
5271 : : #include "gt-cp-coroutines.h"
5272 : :
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