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f9885b8a | 1 | /* Perform -*- C++ -*- constant expression evaluation, including calls to |
2 | constexpr functions. These routines are used both during actual parsing | |
09b42213 | 3 | and during the instantiation of template functions. |
4 | ||
f1717362 | 5 | Copyright (C) 1998-2016 Free Software Foundation, Inc. |
09b42213 | 6 | |
7 | This file is part of GCC. | |
8 | ||
9 | GCC is free software; you can redistribute it and/or modify it | |
10 | under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 3, or (at your option) | |
12 | any later version. | |
13 | ||
14 | GCC is distributed in the hope that it will be useful, but | |
15 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | General Public License 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" | |
09b42213 | 26 | #include "cp-tree.h" |
4cba6f60 | 27 | #include "varasm.h" |
09b42213 | 28 | #include "c-family/c-objc.h" |
29 | #include "tree-iterator.h" | |
30 | #include "gimplify.h" | |
31 | #include "builtins.h" | |
9c96033c | 32 | #include "tree-inline.h" |
6b71bdb4 | 33 | #include "ubsan.h" |
09b42213 | 34 | |
35 | static bool verify_constant (tree, bool, bool *, bool *); | |
36 | #define VERIFY_CONSTANT(X) \ | |
37 | do { \ | |
f83e6885 | 38 | if (verify_constant ((X), ctx->quiet, non_constant_p, overflow_p)) \ |
09b42213 | 39 | return t; \ |
40 | } while (0) | |
41 | ||
42 | /* Returns true iff FUN is an instantiation of a constexpr function | |
43 | template or a defaulted constexpr function. */ | |
44 | ||
45 | bool | |
46 | is_instantiation_of_constexpr (tree fun) | |
47 | { | |
48 | return ((DECL_TEMPLOID_INSTANTIATION (fun) | |
49 | && DECL_DECLARED_CONSTEXPR_P (DECL_TI_TEMPLATE (fun))) | |
50 | || (DECL_DEFAULTED_FN (fun) | |
51 | && DECL_DECLARED_CONSTEXPR_P (fun))); | |
52 | } | |
53 | ||
54 | /* Return true if T is a literal type. */ | |
55 | ||
56 | bool | |
57 | literal_type_p (tree t) | |
58 | { | |
59 | if (SCALAR_TYPE_P (t) | |
76249021 | 60 | || VECTOR_TYPE_P (t) |
dd418b39 | 61 | || TREE_CODE (t) == REFERENCE_TYPE |
62 | || (VOID_TYPE_P (t) && cxx_dialect >= cxx14)) | |
09b42213 | 63 | return true; |
64 | if (CLASS_TYPE_P (t)) | |
65 | { | |
66 | t = complete_type (t); | |
67 | gcc_assert (COMPLETE_TYPE_P (t) || errorcount); | |
68 | return CLASSTYPE_LITERAL_P (t); | |
69 | } | |
70 | if (TREE_CODE (t) == ARRAY_TYPE) | |
71 | return literal_type_p (strip_array_types (t)); | |
72 | return false; | |
73 | } | |
74 | ||
75 | /* If DECL is a variable declared `constexpr', require its type | |
76 | be literal. Return the DECL if OK, otherwise NULL. */ | |
77 | ||
78 | tree | |
79 | ensure_literal_type_for_constexpr_object (tree decl) | |
80 | { | |
81 | tree type = TREE_TYPE (decl); | |
82 | if (VAR_P (decl) | |
83 | && (DECL_DECLARED_CONSTEXPR_P (decl) | |
84 | || var_in_constexpr_fn (decl)) | |
85 | && !processing_template_decl) | |
86 | { | |
87 | tree stype = strip_array_types (type); | |
88 | if (CLASS_TYPE_P (stype) && !COMPLETE_TYPE_P (complete_type (stype))) | |
89 | /* Don't complain here, we'll complain about incompleteness | |
90 | when we try to initialize the variable. */; | |
91 | else if (!literal_type_p (type)) | |
92 | { | |
93 | if (DECL_DECLARED_CONSTEXPR_P (decl)) | |
e45408ff | 94 | { |
95 | error ("the type %qT of constexpr variable %qD is not literal", | |
96 | type, decl); | |
97 | explain_non_literal_class (type); | |
98 | } | |
09b42213 | 99 | else |
9c96033c | 100 | { |
e45408ff | 101 | if (!DECL_TEMPLATE_INSTANTIATION (current_function_decl)) |
102 | { | |
103 | error ("variable %qD of non-literal type %qT in %<constexpr%> " | |
104 | "function", decl, type); | |
105 | explain_non_literal_class (type); | |
106 | } | |
9c96033c | 107 | cp_function_chain->invalid_constexpr = true; |
108 | } | |
09b42213 | 109 | return NULL; |
110 | } | |
111 | } | |
112 | return decl; | |
113 | } | |
114 | ||
115 | /* Representation of entries in the constexpr function definition table. */ | |
116 | ||
117 | struct GTY((for_user)) constexpr_fundef { | |
118 | tree decl; | |
119 | tree body; | |
120 | }; | |
121 | ||
b594087e | 122 | struct constexpr_fundef_hasher : ggc_ptr_hash<constexpr_fundef> |
09b42213 | 123 | { |
124 | static hashval_t hash (constexpr_fundef *); | |
125 | static bool equal (constexpr_fundef *, constexpr_fundef *); | |
126 | }; | |
127 | ||
128 | /* This table holds all constexpr function definitions seen in | |
129 | the current translation unit. */ | |
130 | ||
131 | static GTY (()) hash_table<constexpr_fundef_hasher> *constexpr_fundef_table; | |
132 | ||
133 | /* Utility function used for managing the constexpr function table. | |
134 | Return true if the entries pointed to by P and Q are for the | |
135 | same constexpr function. */ | |
136 | ||
137 | inline bool | |
138 | constexpr_fundef_hasher::equal (constexpr_fundef *lhs, constexpr_fundef *rhs) | |
139 | { | |
140 | return lhs->decl == rhs->decl; | |
141 | } | |
142 | ||
143 | /* Utility function used for managing the constexpr function table. | |
144 | Return a hash value for the entry pointed to by Q. */ | |
145 | ||
146 | inline hashval_t | |
147 | constexpr_fundef_hasher::hash (constexpr_fundef *fundef) | |
148 | { | |
149 | return DECL_UID (fundef->decl); | |
150 | } | |
151 | ||
152 | /* Return a previously saved definition of function FUN. */ | |
153 | ||
154 | static constexpr_fundef * | |
155 | retrieve_constexpr_fundef (tree fun) | |
156 | { | |
157 | constexpr_fundef fundef = { NULL, NULL }; | |
158 | if (constexpr_fundef_table == NULL) | |
159 | return NULL; | |
160 | ||
161 | fundef.decl = fun; | |
162 | return constexpr_fundef_table->find (&fundef); | |
163 | } | |
164 | ||
165 | /* Check whether the parameter and return types of FUN are valid for a | |
166 | constexpr function, and complain if COMPLAIN. */ | |
167 | ||
168 | static bool | |
169 | is_valid_constexpr_fn (tree fun, bool complain) | |
170 | { | |
171 | bool ret = true; | |
172 | ||
173 | if (DECL_INHERITED_CTOR_BASE (fun) | |
174 | && TREE_CODE (fun) == TEMPLATE_DECL) | |
175 | { | |
176 | ret = false; | |
177 | if (complain) | |
178 | error ("inherited constructor %qD is not constexpr", | |
179 | get_inherited_ctor (fun)); | |
180 | } | |
181 | else | |
182 | { | |
183 | for (tree parm = FUNCTION_FIRST_USER_PARM (fun); | |
184 | parm != NULL_TREE; parm = TREE_CHAIN (parm)) | |
185 | if (!literal_type_p (TREE_TYPE (parm))) | |
186 | { | |
187 | ret = false; | |
188 | if (complain) | |
189 | { | |
190 | error ("invalid type for parameter %d of constexpr " | |
191 | "function %q+#D", DECL_PARM_INDEX (parm), fun); | |
192 | explain_non_literal_class (TREE_TYPE (parm)); | |
193 | } | |
194 | } | |
195 | } | |
196 | ||
197 | if (!DECL_CONSTRUCTOR_P (fun)) | |
198 | { | |
199 | tree rettype = TREE_TYPE (TREE_TYPE (fun)); | |
200 | if (!literal_type_p (rettype)) | |
201 | { | |
202 | ret = false; | |
203 | if (complain) | |
204 | { | |
205 | error ("invalid return type %qT of constexpr function %q+D", | |
206 | rettype, fun); | |
207 | explain_non_literal_class (rettype); | |
208 | } | |
209 | } | |
210 | ||
211 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
212 | && !CLASSTYPE_LITERAL_P (DECL_CONTEXT (fun))) | |
213 | { | |
214 | ret = false; | |
215 | if (complain) | |
216 | { | |
217 | error ("enclosing class of constexpr non-static member " | |
218 | "function %q+#D is not a literal type", fun); | |
219 | explain_non_literal_class (DECL_CONTEXT (fun)); | |
220 | } | |
221 | } | |
222 | } | |
223 | else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun))) | |
224 | { | |
225 | ret = false; | |
226 | if (complain) | |
227 | error ("%q#T has virtual base classes", DECL_CONTEXT (fun)); | |
228 | } | |
229 | ||
230 | return ret; | |
231 | } | |
232 | ||
233 | /* Subroutine of build_data_member_initialization. MEMBER is a COMPONENT_REF | |
234 | for a member of an anonymous aggregate, INIT is the initializer for that | |
235 | member, and VEC_OUTER is the vector of constructor elements for the class | |
236 | whose constructor we are processing. Add the initializer to the vector | |
237 | and return true to indicate success. */ | |
238 | ||
239 | static bool | |
240 | build_anon_member_initialization (tree member, tree init, | |
241 | vec<constructor_elt, va_gc> **vec_outer) | |
242 | { | |
243 | /* MEMBER presents the relevant fields from the inside out, but we need | |
244 | to build up the initializer from the outside in so that we can reuse | |
245 | previously built CONSTRUCTORs if this is, say, the second field in an | |
246 | anonymous struct. So we use a vec as a stack. */ | |
247 | auto_vec<tree, 2> fields; | |
248 | do | |
249 | { | |
250 | fields.safe_push (TREE_OPERAND (member, 1)); | |
251 | member = TREE_OPERAND (member, 0); | |
252 | } | |
253 | while (ANON_AGGR_TYPE_P (TREE_TYPE (member)) | |
254 | && TREE_CODE (member) == COMPONENT_REF); | |
255 | ||
256 | /* VEC has the constructor elements vector for the context of FIELD. | |
257 | If FIELD is an anonymous aggregate, we will push inside it. */ | |
258 | vec<constructor_elt, va_gc> **vec = vec_outer; | |
259 | tree field; | |
260 | while (field = fields.pop(), | |
261 | ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
262 | { | |
263 | tree ctor; | |
264 | /* If there is already an outer constructor entry for the anonymous | |
265 | aggregate FIELD, use it; otherwise, insert one. */ | |
266 | if (vec_safe_is_empty (*vec) | |
267 | || (*vec)->last().index != field) | |
268 | { | |
269 | ctor = build_constructor (TREE_TYPE (field), NULL); | |
270 | CONSTRUCTOR_APPEND_ELT (*vec, field, ctor); | |
271 | } | |
272 | else | |
273 | ctor = (*vec)->last().value; | |
274 | vec = &CONSTRUCTOR_ELTS (ctor); | |
275 | } | |
276 | ||
277 | /* Now we're at the innermost field, the one that isn't an anonymous | |
278 | aggregate. Add its initializer to the CONSTRUCTOR and we're done. */ | |
279 | gcc_assert (fields.is_empty()); | |
280 | CONSTRUCTOR_APPEND_ELT (*vec, field, init); | |
281 | ||
282 | return true; | |
283 | } | |
284 | ||
285 | /* Subroutine of build_constexpr_constructor_member_initializers. | |
286 | The expression tree T represents a data member initialization | |
287 | in a (constexpr) constructor definition. Build a pairing of | |
288 | the data member with its initializer, and prepend that pair | |
289 | to the existing initialization pair INITS. */ | |
290 | ||
291 | static bool | |
292 | build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec) | |
293 | { | |
294 | tree member, init; | |
295 | if (TREE_CODE (t) == CLEANUP_POINT_EXPR) | |
296 | t = TREE_OPERAND (t, 0); | |
297 | if (TREE_CODE (t) == EXPR_STMT) | |
298 | t = TREE_OPERAND (t, 0); | |
299 | if (t == error_mark_node) | |
300 | return false; | |
301 | if (TREE_CODE (t) == STATEMENT_LIST) | |
302 | { | |
303 | tree_stmt_iterator i; | |
304 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
305 | { | |
306 | if (! build_data_member_initialization (tsi_stmt (i), vec)) | |
307 | return false; | |
308 | } | |
309 | return true; | |
310 | } | |
311 | if (TREE_CODE (t) == CLEANUP_STMT) | |
312 | { | |
313 | /* We can't see a CLEANUP_STMT in a constructor for a literal class, | |
314 | but we can in a constexpr constructor for a non-literal class. Just | |
315 | ignore it; either all the initialization will be constant, in which | |
316 | case the cleanup can't run, or it can't be constexpr. | |
317 | Still recurse into CLEANUP_BODY. */ | |
318 | return build_data_member_initialization (CLEANUP_BODY (t), vec); | |
319 | } | |
320 | if (TREE_CODE (t) == CONVERT_EXPR) | |
321 | t = TREE_OPERAND (t, 0); | |
322 | if (TREE_CODE (t) == INIT_EXPR | |
9c96033c | 323 | /* vptr initialization shows up as a MODIFY_EXPR. In C++14 we only |
324 | use what this function builds for cx_check_missing_mem_inits, and | |
325 | assignment in the ctor body doesn't count. */ | |
326 | || (cxx_dialect < cxx14 && TREE_CODE (t) == MODIFY_EXPR)) | |
09b42213 | 327 | { |
328 | member = TREE_OPERAND (t, 0); | |
329 | init = break_out_target_exprs (TREE_OPERAND (t, 1)); | |
330 | } | |
331 | else if (TREE_CODE (t) == CALL_EXPR) | |
332 | { | |
9c96033c | 333 | tree fn = get_callee_fndecl (t); |
334 | if (!fn || !DECL_CONSTRUCTOR_P (fn)) | |
335 | /* We're only interested in calls to subobject constructors. */ | |
336 | return true; | |
09b42213 | 337 | member = CALL_EXPR_ARG (t, 0); |
338 | /* We don't use build_cplus_new here because it complains about | |
339 | abstract bases. Leaving the call unwrapped means that it has the | |
340 | wrong type, but cxx_eval_constant_expression doesn't care. */ | |
341 | init = break_out_target_exprs (t); | |
342 | } | |
343 | else if (TREE_CODE (t) == BIND_EXPR) | |
344 | return build_data_member_initialization (BIND_EXPR_BODY (t), vec); | |
09b42213 | 345 | else |
9c96033c | 346 | /* Don't add anything else to the CONSTRUCTOR. */ |
347 | return true; | |
09b42213 | 348 | if (INDIRECT_REF_P (member)) |
349 | member = TREE_OPERAND (member, 0); | |
350 | if (TREE_CODE (member) == NOP_EXPR) | |
351 | { | |
352 | tree op = member; | |
353 | STRIP_NOPS (op); | |
354 | if (TREE_CODE (op) == ADDR_EXPR) | |
355 | { | |
356 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
357 | (TREE_TYPE (TREE_TYPE (op)), | |
358 | TREE_TYPE (TREE_TYPE (member)))); | |
359 | /* Initializing a cv-qualified member; we need to look through | |
360 | the const_cast. */ | |
361 | member = op; | |
362 | } | |
363 | else if (op == current_class_ptr | |
364 | && (same_type_ignoring_top_level_qualifiers_p | |
365 | (TREE_TYPE (TREE_TYPE (member)), | |
366 | current_class_type))) | |
367 | /* Delegating constructor. */ | |
368 | member = op; | |
369 | else | |
370 | { | |
371 | /* This is an initializer for an empty base; keep it for now so | |
372 | we can check it in cxx_eval_bare_aggregate. */ | |
373 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (member)))); | |
374 | } | |
375 | } | |
376 | if (TREE_CODE (member) == ADDR_EXPR) | |
377 | member = TREE_OPERAND (member, 0); | |
378 | if (TREE_CODE (member) == COMPONENT_REF) | |
379 | { | |
380 | tree aggr = TREE_OPERAND (member, 0); | |
381 | if (TREE_CODE (aggr) != COMPONENT_REF) | |
382 | /* Normal member initialization. */ | |
383 | member = TREE_OPERAND (member, 1); | |
384 | else if (ANON_AGGR_TYPE_P (TREE_TYPE (aggr))) | |
385 | /* Initializing a member of an anonymous union. */ | |
386 | return build_anon_member_initialization (member, init, vec); | |
387 | else | |
388 | /* We're initializing a vtable pointer in a base. Leave it as | |
389 | COMPONENT_REF so we remember the path to get to the vfield. */ | |
390 | gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node); | |
391 | } | |
392 | ||
393 | CONSTRUCTOR_APPEND_ELT (*vec, member, init); | |
394 | return true; | |
395 | } | |
396 | ||
397 | /* Subroutine of check_constexpr_ctor_body_1 and constexpr_fn_retval. | |
398 | In C++11 mode checks that the TYPE_DECLs in the BIND_EXPR_VARS of a | |
399 | BIND_EXPR conform to 7.1.5/3/4 on typedef and alias declarations. */ | |
400 | ||
401 | static bool | |
402 | check_constexpr_bind_expr_vars (tree t) | |
403 | { | |
404 | gcc_assert (TREE_CODE (t) == BIND_EXPR); | |
405 | ||
09b42213 | 406 | for (tree var = BIND_EXPR_VARS (t); var; var = DECL_CHAIN (var)) |
407 | if (TREE_CODE (var) == TYPE_DECL | |
04103c39 | 408 | && DECL_IMPLICIT_TYPEDEF_P (var) |
409 | && !LAMBDA_TYPE_P (TREE_TYPE (var))) | |
09b42213 | 410 | return false; |
411 | return true; | |
412 | } | |
413 | ||
414 | /* Subroutine of check_constexpr_ctor_body. */ | |
415 | ||
416 | static bool | |
417 | check_constexpr_ctor_body_1 (tree last, tree list) | |
418 | { | |
419 | switch (TREE_CODE (list)) | |
420 | { | |
421 | case DECL_EXPR: | |
422 | if (TREE_CODE (DECL_EXPR_DECL (list)) == USING_DECL) | |
423 | return true; | |
09b42213 | 424 | return false; |
425 | ||
426 | case CLEANUP_POINT_EXPR: | |
427 | return check_constexpr_ctor_body (last, TREE_OPERAND (list, 0), | |
428 | /*complain=*/false); | |
429 | ||
430 | case BIND_EXPR: | |
431 | if (!check_constexpr_bind_expr_vars (list) | |
432 | || !check_constexpr_ctor_body (last, BIND_EXPR_BODY (list), | |
433 | /*complain=*/false)) | |
434 | return false; | |
435 | return true; | |
436 | ||
437 | case USING_STMT: | |
438 | case STATIC_ASSERT: | |
439 | return true; | |
440 | ||
441 | default: | |
442 | return false; | |
443 | } | |
444 | } | |
445 | ||
446 | /* Make sure that there are no statements after LAST in the constructor | |
447 | body represented by LIST. */ | |
448 | ||
449 | bool | |
450 | check_constexpr_ctor_body (tree last, tree list, bool complain) | |
451 | { | |
9c96033c | 452 | /* C++14 doesn't require a constexpr ctor to have an empty body. */ |
453 | if (cxx_dialect >= cxx14) | |
454 | return true; | |
455 | ||
09b42213 | 456 | bool ok = true; |
457 | if (TREE_CODE (list) == STATEMENT_LIST) | |
458 | { | |
459 | tree_stmt_iterator i = tsi_last (list); | |
460 | for (; !tsi_end_p (i); tsi_prev (&i)) | |
461 | { | |
462 | tree t = tsi_stmt (i); | |
463 | if (t == last) | |
464 | break; | |
465 | if (!check_constexpr_ctor_body_1 (last, t)) | |
466 | { | |
467 | ok = false; | |
468 | break; | |
469 | } | |
470 | } | |
471 | } | |
472 | else if (list != last | |
473 | && !check_constexpr_ctor_body_1 (last, list)) | |
474 | ok = false; | |
475 | if (!ok) | |
476 | { | |
477 | if (complain) | |
478 | error ("constexpr constructor does not have empty body"); | |
479 | DECL_DECLARED_CONSTEXPR_P (current_function_decl) = false; | |
480 | } | |
481 | return ok; | |
482 | } | |
483 | ||
484 | /* V is a vector of constructor elements built up for the base and member | |
485 | initializers of a constructor for TYPE. They need to be in increasing | |
486 | offset order, which they might not be yet if TYPE has a primary base | |
487 | which is not first in the base-clause or a vptr and at least one base | |
488 | all of which are non-primary. */ | |
489 | ||
490 | static vec<constructor_elt, va_gc> * | |
491 | sort_constexpr_mem_initializers (tree type, vec<constructor_elt, va_gc> *v) | |
492 | { | |
493 | tree pri = CLASSTYPE_PRIMARY_BINFO (type); | |
494 | tree field_type; | |
495 | unsigned i; | |
496 | constructor_elt *ce; | |
497 | ||
498 | if (pri) | |
499 | field_type = BINFO_TYPE (pri); | |
500 | else if (TYPE_CONTAINS_VPTR_P (type)) | |
501 | field_type = vtbl_ptr_type_node; | |
502 | else | |
503 | return v; | |
504 | ||
505 | /* Find the element for the primary base or vptr and move it to the | |
506 | beginning of the vec. */ | |
507 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
508 | if (TREE_TYPE (ce->index) == field_type) | |
509 | break; | |
510 | ||
511 | if (i > 0 && i < vec_safe_length (v)) | |
512 | { | |
513 | vec<constructor_elt, va_gc> &vref = *v; | |
514 | constructor_elt elt = vref[i]; | |
515 | for (; i > 0; --i) | |
516 | vref[i] = vref[i-1]; | |
517 | vref[0] = elt; | |
518 | } | |
519 | ||
520 | return v; | |
521 | } | |
522 | ||
523 | /* Build compile-time evalable representations of member-initializer list | |
524 | for a constexpr constructor. */ | |
525 | ||
526 | static tree | |
527 | build_constexpr_constructor_member_initializers (tree type, tree body) | |
528 | { | |
529 | vec<constructor_elt, va_gc> *vec = NULL; | |
530 | bool ok = true; | |
531 | if (TREE_CODE (body) == MUST_NOT_THROW_EXPR | |
532 | || TREE_CODE (body) == EH_SPEC_BLOCK) | |
533 | body = TREE_OPERAND (body, 0); | |
534 | if (TREE_CODE (body) == STATEMENT_LIST) | |
8a36d0ec | 535 | { |
dc70c770 | 536 | for (tree_stmt_iterator i = tsi_start (body); |
537 | !tsi_end_p (i); tsi_next (&i)) | |
8a36d0ec | 538 | { |
539 | body = tsi_stmt (i); | |
540 | if (TREE_CODE (body) == BIND_EXPR) | |
541 | break; | |
8a36d0ec | 542 | } |
543 | } | |
dc70c770 | 544 | if (TREE_CODE (body) == BIND_EXPR) |
545 | body = BIND_EXPR_BODY (body); | |
09b42213 | 546 | if (TREE_CODE (body) == CLEANUP_POINT_EXPR) |
547 | { | |
548 | body = TREE_OPERAND (body, 0); | |
549 | if (TREE_CODE (body) == EXPR_STMT) | |
550 | body = TREE_OPERAND (body, 0); | |
551 | if (TREE_CODE (body) == INIT_EXPR | |
552 | && (same_type_ignoring_top_level_qualifiers_p | |
553 | (TREE_TYPE (TREE_OPERAND (body, 0)), | |
554 | current_class_type))) | |
555 | { | |
556 | /* Trivial copy. */ | |
557 | return TREE_OPERAND (body, 1); | |
558 | } | |
559 | ok = build_data_member_initialization (body, &vec); | |
560 | } | |
561 | else if (TREE_CODE (body) == STATEMENT_LIST) | |
562 | { | |
563 | tree_stmt_iterator i; | |
564 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
565 | { | |
566 | ok = build_data_member_initialization (tsi_stmt (i), &vec); | |
567 | if (!ok) | |
568 | break; | |
569 | } | |
570 | } | |
571 | else if (TREE_CODE (body) == TRY_BLOCK) | |
572 | { | |
573 | error ("body of %<constexpr%> constructor cannot be " | |
574 | "a function-try-block"); | |
575 | return error_mark_node; | |
576 | } | |
577 | else if (EXPR_P (body)) | |
578 | ok = build_data_member_initialization (body, &vec); | |
579 | else | |
580 | gcc_assert (errorcount > 0); | |
581 | if (ok) | |
582 | { | |
583 | if (vec_safe_length (vec) > 0) | |
584 | { | |
585 | /* In a delegating constructor, return the target. */ | |
586 | constructor_elt *ce = &(*vec)[0]; | |
587 | if (ce->index == current_class_ptr) | |
588 | { | |
589 | body = ce->value; | |
590 | vec_free (vec); | |
591 | return body; | |
592 | } | |
593 | } | |
594 | vec = sort_constexpr_mem_initializers (type, vec); | |
595 | return build_constructor (type, vec); | |
596 | } | |
597 | else | |
598 | return error_mark_node; | |
599 | } | |
600 | ||
601 | /* Subroutine of register_constexpr_fundef. BODY is the body of a function | |
602 | declared to be constexpr, or a sub-statement thereof. Returns the | |
603 | return value if suitable, error_mark_node for a statement not allowed in | |
604 | a constexpr function, or NULL_TREE if no return value was found. */ | |
605 | ||
606 | static tree | |
607 | constexpr_fn_retval (tree body) | |
608 | { | |
609 | switch (TREE_CODE (body)) | |
610 | { | |
611 | case STATEMENT_LIST: | |
612 | { | |
613 | tree_stmt_iterator i; | |
614 | tree expr = NULL_TREE; | |
615 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
616 | { | |
617 | tree s = constexpr_fn_retval (tsi_stmt (i)); | |
618 | if (s == error_mark_node) | |
619 | return error_mark_node; | |
620 | else if (s == NULL_TREE) | |
621 | /* Keep iterating. */; | |
622 | else if (expr) | |
623 | /* Multiple return statements. */ | |
624 | return error_mark_node; | |
625 | else | |
626 | expr = s; | |
627 | } | |
628 | return expr; | |
629 | } | |
630 | ||
631 | case RETURN_EXPR: | |
632 | return break_out_target_exprs (TREE_OPERAND (body, 0)); | |
633 | ||
634 | case DECL_EXPR: | |
394aed6a | 635 | { |
636 | tree decl = DECL_EXPR_DECL (body); | |
637 | if (TREE_CODE (decl) == USING_DECL | |
638 | /* Accept __func__, __FUNCTION__, and __PRETTY_FUNCTION__. */ | |
639 | || DECL_ARTIFICIAL (decl)) | |
640 | return NULL_TREE; | |
641 | return error_mark_node; | |
642 | } | |
09b42213 | 643 | |
644 | case CLEANUP_POINT_EXPR: | |
645 | return constexpr_fn_retval (TREE_OPERAND (body, 0)); | |
646 | ||
647 | case BIND_EXPR: | |
648 | if (!check_constexpr_bind_expr_vars (body)) | |
649 | return error_mark_node; | |
650 | return constexpr_fn_retval (BIND_EXPR_BODY (body)); | |
651 | ||
652 | case USING_STMT: | |
653 | return NULL_TREE; | |
654 | ||
655 | default: | |
656 | return error_mark_node; | |
657 | } | |
658 | } | |
659 | ||
660 | /* Subroutine of register_constexpr_fundef. BODY is the DECL_SAVED_TREE of | |
661 | FUN; do the necessary transformations to turn it into a single expression | |
662 | that we can store in the hash table. */ | |
663 | ||
664 | static tree | |
665 | massage_constexpr_body (tree fun, tree body) | |
666 | { | |
667 | if (DECL_CONSTRUCTOR_P (fun)) | |
668 | body = build_constexpr_constructor_member_initializers | |
669 | (DECL_CONTEXT (fun), body); | |
9c96033c | 670 | else if (cxx_dialect < cxx14) |
09b42213 | 671 | { |
672 | if (TREE_CODE (body) == EH_SPEC_BLOCK) | |
673 | body = EH_SPEC_STMTS (body); | |
674 | if (TREE_CODE (body) == MUST_NOT_THROW_EXPR) | |
675 | body = TREE_OPERAND (body, 0); | |
676 | body = constexpr_fn_retval (body); | |
677 | } | |
678 | return body; | |
679 | } | |
680 | ||
681 | /* FUN is a constexpr constructor with massaged body BODY. Return true | |
682 | if some bases/fields are uninitialized, and complain if COMPLAIN. */ | |
683 | ||
684 | static bool | |
685 | cx_check_missing_mem_inits (tree fun, tree body, bool complain) | |
686 | { | |
687 | bool bad; | |
688 | tree field; | |
689 | unsigned i, nelts; | |
690 | tree ctype; | |
691 | ||
692 | if (TREE_CODE (body) != CONSTRUCTOR) | |
693 | return false; | |
694 | ||
695 | nelts = CONSTRUCTOR_NELTS (body); | |
696 | ctype = DECL_CONTEXT (fun); | |
697 | field = TYPE_FIELDS (ctype); | |
698 | ||
699 | if (TREE_CODE (ctype) == UNION_TYPE) | |
700 | { | |
701 | if (nelts == 0 && next_initializable_field (field)) | |
702 | { | |
703 | if (complain) | |
704 | error ("%<constexpr%> constructor for union %qT must " | |
705 | "initialize exactly one non-static data member", ctype); | |
706 | return true; | |
707 | } | |
708 | return false; | |
709 | } | |
710 | ||
711 | bad = false; | |
712 | for (i = 0; i <= nelts; ++i) | |
713 | { | |
714 | tree index; | |
715 | if (i == nelts) | |
716 | index = NULL_TREE; | |
717 | else | |
718 | { | |
719 | index = CONSTRUCTOR_ELT (body, i)->index; | |
720 | /* Skip base and vtable inits. */ | |
721 | if (TREE_CODE (index) != FIELD_DECL | |
722 | || DECL_ARTIFICIAL (index)) | |
723 | continue; | |
724 | } | |
725 | for (; field != index; field = DECL_CHAIN (field)) | |
726 | { | |
727 | tree ftype; | |
728 | if (TREE_CODE (field) != FIELD_DECL | |
729 | || (DECL_C_BIT_FIELD (field) && !DECL_NAME (field)) | |
730 | || DECL_ARTIFICIAL (field)) | |
731 | continue; | |
732 | ftype = strip_array_types (TREE_TYPE (field)); | |
733 | if (type_has_constexpr_default_constructor (ftype)) | |
734 | { | |
735 | /* It's OK to skip a member with a trivial constexpr ctor. | |
736 | A constexpr ctor that isn't trivial should have been | |
737 | added in by now. */ | |
738 | gcc_checking_assert (!TYPE_HAS_COMPLEX_DFLT (ftype) | |
739 | || errorcount != 0); | |
740 | continue; | |
741 | } | |
742 | if (!complain) | |
743 | return true; | |
859e2c29 | 744 | error ("member %qD must be initialized by mem-initializer " |
745 | "in %<constexpr%> constructor", field); | |
746 | inform (DECL_SOURCE_LOCATION (field), "declared here"); | |
09b42213 | 747 | bad = true; |
748 | } | |
749 | if (field == NULL_TREE) | |
750 | break; | |
751 | field = DECL_CHAIN (field); | |
752 | } | |
753 | ||
754 | return bad; | |
755 | } | |
756 | ||
757 | /* We are processing the definition of the constexpr function FUN. | |
758 | Check that its BODY fulfills the propriate requirements and | |
759 | enter it in the constexpr function definition table. | |
760 | For constructor BODY is actually the TREE_LIST of the | |
761 | member-initializer list. */ | |
762 | ||
763 | tree | |
764 | register_constexpr_fundef (tree fun, tree body) | |
765 | { | |
766 | constexpr_fundef entry; | |
767 | constexpr_fundef **slot; | |
768 | ||
769 | if (!is_valid_constexpr_fn (fun, !DECL_GENERATED_P (fun))) | |
770 | return NULL; | |
771 | ||
772 | body = massage_constexpr_body (fun, body); | |
773 | if (body == NULL_TREE || body == error_mark_node) | |
774 | { | |
775 | if (!DECL_CONSTRUCTOR_P (fun)) | |
776 | error ("body of constexpr function %qD not a return-statement", fun); | |
777 | return NULL; | |
778 | } | |
779 | ||
780 | if (!potential_rvalue_constant_expression (body)) | |
781 | { | |
782 | if (!DECL_GENERATED_P (fun)) | |
783 | require_potential_rvalue_constant_expression (body); | |
784 | return NULL; | |
785 | } | |
786 | ||
787 | if (DECL_CONSTRUCTOR_P (fun) | |
788 | && cx_check_missing_mem_inits (fun, body, !DECL_GENERATED_P (fun))) | |
789 | return NULL; | |
790 | ||
791 | /* Create the constexpr function table if necessary. */ | |
792 | if (constexpr_fundef_table == NULL) | |
793 | constexpr_fundef_table | |
794 | = hash_table<constexpr_fundef_hasher>::create_ggc (101); | |
795 | ||
796 | entry.decl = fun; | |
797 | entry.body = body; | |
798 | slot = constexpr_fundef_table->find_slot (&entry, INSERT); | |
799 | ||
800 | gcc_assert (*slot == NULL); | |
801 | *slot = ggc_alloc<constexpr_fundef> (); | |
802 | **slot = entry; | |
803 | ||
804 | return fun; | |
805 | } | |
806 | ||
807 | /* FUN is a non-constexpr function called in a context that requires a | |
808 | constant expression. If it comes from a constexpr template, explain why | |
809 | the instantiation isn't constexpr. */ | |
810 | ||
811 | void | |
812 | explain_invalid_constexpr_fn (tree fun) | |
813 | { | |
814 | static hash_set<tree> *diagnosed; | |
815 | tree body; | |
816 | location_t save_loc; | |
817 | /* Only diagnose defaulted functions or instantiations. */ | |
818 | if (!DECL_DEFAULTED_FN (fun) | |
819 | && !is_instantiation_of_constexpr (fun)) | |
820 | return; | |
821 | if (diagnosed == NULL) | |
822 | diagnosed = new hash_set<tree>; | |
823 | if (diagnosed->add (fun)) | |
824 | /* Already explained. */ | |
825 | return; | |
826 | ||
827 | save_loc = input_location; | |
828 | input_location = DECL_SOURCE_LOCATION (fun); | |
66ed189d | 829 | inform (input_location, |
830 | "%qD is not usable as a constexpr function because:", fun); | |
09b42213 | 831 | /* First check the declaration. */ |
832 | if (is_valid_constexpr_fn (fun, true)) | |
833 | { | |
834 | /* Then if it's OK, the body. */ | |
835 | if (!DECL_DECLARED_CONSTEXPR_P (fun)) | |
836 | explain_implicit_non_constexpr (fun); | |
837 | else | |
838 | { | |
839 | body = massage_constexpr_body (fun, DECL_SAVED_TREE (fun)); | |
840 | require_potential_rvalue_constant_expression (body); | |
841 | if (DECL_CONSTRUCTOR_P (fun)) | |
842 | cx_check_missing_mem_inits (fun, body, true); | |
843 | } | |
844 | } | |
845 | input_location = save_loc; | |
846 | } | |
847 | ||
848 | /* Objects of this type represent calls to constexpr functions | |
849 | along with the bindings of parameters to their arguments, for | |
850 | the purpose of compile time evaluation. */ | |
851 | ||
852 | struct GTY((for_user)) constexpr_call { | |
853 | /* Description of the constexpr function definition. */ | |
854 | constexpr_fundef *fundef; | |
855 | /* Parameter bindings environment. A TREE_LIST where each TREE_PURPOSE | |
856 | is a parameter _DECL and the TREE_VALUE is the value of the parameter. | |
857 | Note: This arrangement is made to accommodate the use of | |
858 | iterative_hash_template_arg (see pt.c). If you change this | |
859 | representation, also change the hash calculation in | |
860 | cxx_eval_call_expression. */ | |
861 | tree bindings; | |
862 | /* Result of the call. | |
863 | NULL means the call is being evaluated. | |
864 | error_mark_node means that the evaluation was erroneous; | |
865 | otherwise, the actuall value of the call. */ | |
866 | tree result; | |
867 | /* The hash of this call; we remember it here to avoid having to | |
868 | recalculate it when expanding the hash table. */ | |
869 | hashval_t hash; | |
870 | }; | |
871 | ||
b594087e | 872 | struct constexpr_call_hasher : ggc_ptr_hash<constexpr_call> |
09b42213 | 873 | { |
874 | static hashval_t hash (constexpr_call *); | |
875 | static bool equal (constexpr_call *, constexpr_call *); | |
cf72f34d | 876 | }; |
877 | ||
878 | /* The constexpr expansion context. CALL is the current function | |
879 | expansion, CTOR is the current aggregate initializer, OBJECT is the | |
880 | object being initialized by CTOR, either a VAR_DECL or a _REF. VALUES | |
881 | is a map of values of variables initialized within the expression. */ | |
882 | ||
883 | struct constexpr_ctx { | |
f9885b8a | 884 | /* The innermost call we're evaluating. */ |
cf72f34d | 885 | constexpr_call *call; |
f9885b8a | 886 | /* Values for any temporaries or local variables within the |
887 | constant-expression. */ | |
cf72f34d | 888 | hash_map<tree,tree> *values; |
f9885b8a | 889 | /* The CONSTRUCTOR we're currently building up for an aggregate |
890 | initializer. */ | |
cf72f34d | 891 | tree ctor; |
f9885b8a | 892 | /* The object we're building the CONSTRUCTOR for. */ |
cf72f34d | 893 | tree object; |
f9885b8a | 894 | /* Whether we should error on a non-constant expression or fail quietly. */ |
f83e6885 | 895 | bool quiet; |
f9885b8a | 896 | /* Whether we are strictly conforming to constant expression rules or |
897 | trying harder to get a constant value. */ | |
2055d27a | 898 | bool strict; |
cf72f34d | 899 | }; |
09b42213 | 900 | |
901 | /* A table of all constexpr calls that have been evaluated by the | |
902 | compiler in this translation unit. */ | |
903 | ||
904 | static GTY (()) hash_table<constexpr_call_hasher> *constexpr_call_table; | |
905 | ||
cf72f34d | 906 | static tree cxx_eval_constant_expression (const constexpr_ctx *, tree, |
b2a43197 | 907 | bool, bool *, bool *, tree * = NULL); |
09b42213 | 908 | |
909 | /* Compute a hash value for a constexpr call representation. */ | |
910 | ||
911 | inline hashval_t | |
912 | constexpr_call_hasher::hash (constexpr_call *info) | |
913 | { | |
914 | return info->hash; | |
915 | } | |
916 | ||
917 | /* Return true if the objects pointed to by P and Q represent calls | |
918 | to the same constexpr function with the same arguments. | |
919 | Otherwise, return false. */ | |
920 | ||
921 | bool | |
922 | constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs) | |
923 | { | |
924 | tree lhs_bindings; | |
925 | tree rhs_bindings; | |
926 | if (lhs == rhs) | |
927 | return 1; | |
928 | if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef)) | |
929 | return 0; | |
930 | lhs_bindings = lhs->bindings; | |
931 | rhs_bindings = rhs->bindings; | |
932 | while (lhs_bindings != NULL && rhs_bindings != NULL) | |
933 | { | |
934 | tree lhs_arg = TREE_VALUE (lhs_bindings); | |
935 | tree rhs_arg = TREE_VALUE (rhs_bindings); | |
936 | gcc_assert (TREE_TYPE (lhs_arg) == TREE_TYPE (rhs_arg)); | |
937 | if (!cp_tree_equal (lhs_arg, rhs_arg)) | |
938 | return 0; | |
939 | lhs_bindings = TREE_CHAIN (lhs_bindings); | |
940 | rhs_bindings = TREE_CHAIN (rhs_bindings); | |
941 | } | |
942 | return lhs_bindings == rhs_bindings; | |
943 | } | |
944 | ||
945 | /* Initialize the constexpr call table, if needed. */ | |
946 | ||
947 | static void | |
948 | maybe_initialize_constexpr_call_table (void) | |
949 | { | |
950 | if (constexpr_call_table == NULL) | |
951 | constexpr_call_table = hash_table<constexpr_call_hasher>::create_ggc (101); | |
952 | } | |
953 | ||
954 | /* We have an expression tree T that represents a call, either CALL_EXPR | |
955 | or AGGR_INIT_EXPR. If the call is lexically to a named function, | |
956 | retrun the _DECL for that function. */ | |
957 | ||
958 | static tree | |
959 | get_function_named_in_call (tree t) | |
960 | { | |
961 | tree fun = NULL; | |
962 | switch (TREE_CODE (t)) | |
963 | { | |
964 | case CALL_EXPR: | |
965 | fun = CALL_EXPR_FN (t); | |
966 | break; | |
967 | ||
968 | case AGGR_INIT_EXPR: | |
969 | fun = AGGR_INIT_EXPR_FN (t); | |
970 | break; | |
971 | ||
972 | default: | |
973 | gcc_unreachable(); | |
974 | break; | |
975 | } | |
9c96033c | 976 | if (fun && TREE_CODE (fun) == ADDR_EXPR |
09b42213 | 977 | && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL) |
978 | fun = TREE_OPERAND (fun, 0); | |
979 | return fun; | |
980 | } | |
981 | ||
982 | /* We have an expression tree T that represents a call, either CALL_EXPR | |
983 | or AGGR_INIT_EXPR. Return the Nth argument. */ | |
984 | ||
985 | static inline tree | |
986 | get_nth_callarg (tree t, int n) | |
987 | { | |
988 | switch (TREE_CODE (t)) | |
989 | { | |
990 | case CALL_EXPR: | |
991 | return CALL_EXPR_ARG (t, n); | |
992 | ||
993 | case AGGR_INIT_EXPR: | |
994 | return AGGR_INIT_EXPR_ARG (t, n); | |
995 | ||
996 | default: | |
997 | gcc_unreachable (); | |
998 | return NULL; | |
999 | } | |
1000 | } | |
1001 | ||
09b42213 | 1002 | /* Attempt to evaluate T which represents a call to a builtin function. |
1003 | We assume here that all builtin functions evaluate to scalar types | |
1004 | represented by _CST nodes. */ | |
1005 | ||
1006 | static tree | |
f1c6af10 | 1007 | cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, |
1227ba74 | 1008 | bool lval, |
09b42213 | 1009 | bool *non_constant_p, bool *overflow_p) |
1010 | { | |
1011 | const int nargs = call_expr_nargs (t); | |
1012 | tree *args = (tree *) alloca (nargs * sizeof (tree)); | |
1013 | tree new_call; | |
1014 | int i; | |
f1c6af10 | 1015 | |
1016 | /* Don't fold __builtin_constant_p within a constexpr function. */ | |
efe6a40a | 1017 | bool bi_const_p = (DECL_FUNCTION_CODE (fun) == BUILT_IN_CONSTANT_P); |
1018 | ||
1019 | if (bi_const_p | |
f1c6af10 | 1020 | && current_function_decl |
1021 | && DECL_DECLARED_CONSTEXPR_P (current_function_decl)) | |
09b42213 | 1022 | { |
f1c6af10 | 1023 | *non_constant_p = true; |
1024 | return t; | |
09b42213 | 1025 | } |
f1c6af10 | 1026 | |
1027 | /* Be permissive for arguments to built-ins; __builtin_constant_p should | |
1028 | return constant false for a non-constant argument. */ | |
1029 | constexpr_ctx new_ctx = *ctx; | |
1030 | new_ctx.quiet = true; | |
1031 | bool dummy1 = false, dummy2 = false; | |
1032 | for (i = 0; i < nargs; ++i) | |
efe6a40a | 1033 | { |
1034 | args[i] = cxx_eval_constant_expression (&new_ctx, CALL_EXPR_ARG (t, i), | |
1035 | lval, &dummy1, &dummy2); | |
1036 | if (bi_const_p) | |
1037 | /* For __built_in_constant_p, fold all expressions with constant values | |
1038 | even if they aren't C++ constant-expressions. */ | |
1039 | args[i] = cp_fully_fold (args[i]); | |
1040 | } | |
f1c6af10 | 1041 | |
1042 | bool save_ffbcp = force_folding_builtin_constant_p; | |
1043 | force_folding_builtin_constant_p = true; | |
9d884767 | 1044 | new_call = fold_build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t), |
1045 | CALL_EXPR_FN (t), nargs, args); | |
d2c63826 | 1046 | /* Fold away the NOP_EXPR from fold_builtin_n. */ |
1047 | new_call = fold (new_call); | |
f1c6af10 | 1048 | force_folding_builtin_constant_p = save_ffbcp; |
09b42213 | 1049 | VERIFY_CONSTANT (new_call); |
1050 | return new_call; | |
1051 | } | |
1052 | ||
1053 | /* TEMP is the constant value of a temporary object of type TYPE. Adjust | |
1054 | the type of the value to match. */ | |
1055 | ||
1056 | static tree | |
1057 | adjust_temp_type (tree type, tree temp) | |
1058 | { | |
1059 | if (TREE_TYPE (temp) == type) | |
1060 | return temp; | |
1061 | /* Avoid wrapping an aggregate value in a NOP_EXPR. */ | |
1062 | if (TREE_CODE (temp) == CONSTRUCTOR) | |
1063 | return build_constructor (type, CONSTRUCTOR_ELTS (temp)); | |
1064 | gcc_assert (scalarish_type_p (type)); | |
1065 | return cp_fold_convert (type, temp); | |
1066 | } | |
1067 | ||
1068 | /* Subroutine of cxx_eval_call_expression. | |
1069 | We are processing a call expression (either CALL_EXPR or | |
cf72f34d | 1070 | AGGR_INIT_EXPR) in the context of CTX. Evaluate |
09b42213 | 1071 | all arguments and bind their values to correspondings |
1072 | parameters, making up the NEW_CALL context. */ | |
1073 | ||
1074 | static void | |
cf72f34d | 1075 | cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, |
09b42213 | 1076 | constexpr_call *new_call, |
c8f6aeb1 | 1077 | bool *non_constant_p, bool *overflow_p, |
1078 | bool *non_constant_args) | |
09b42213 | 1079 | { |
1080 | const int nargs = call_expr_nargs (t); | |
1081 | tree fun = new_call->fundef->decl; | |
1082 | tree parms = DECL_ARGUMENTS (fun); | |
1083 | int i; | |
9c96033c | 1084 | tree *p = &new_call->bindings; |
09b42213 | 1085 | for (i = 0; i < nargs; ++i) |
1086 | { | |
1087 | tree x, arg; | |
1088 | tree type = parms ? TREE_TYPE (parms) : void_type_node; | |
09b42213 | 1089 | x = get_nth_callarg (t, i); |
cf72f34d | 1090 | /* For member function, the first argument is a pointer to the implied |
1091 | object. For a constructor, it might still be a dummy object, in | |
9c96033c | 1092 | which case we get the real argument from ctx. */ |
cf72f34d | 1093 | if (i == 0 && DECL_CONSTRUCTOR_P (fun) |
1094 | && is_dummy_object (x)) | |
1095 | { | |
1096 | x = ctx->object; | |
cf72f34d | 1097 | x = cp_build_addr_expr (x, tf_warning_or_error); |
1098 | } | |
1227ba74 | 1099 | bool lval = false; |
1227ba74 | 1100 | arg = cxx_eval_constant_expression (ctx, x, lval, |
b2a43197 | 1101 | non_constant_p, overflow_p); |
09b42213 | 1102 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 1103 | if (*non_constant_p && ctx->quiet) |
09b42213 | 1104 | return; |
1105 | /* Just discard ellipsis args after checking their constantitude. */ | |
1106 | if (!parms) | |
1107 | continue; | |
1108 | if (*non_constant_p) | |
1109 | /* Don't try to adjust the type of non-constant args. */ | |
1110 | goto next; | |
1111 | ||
1112 | /* Make sure the binding has the same type as the parm. */ | |
1113 | if (TREE_CODE (type) != REFERENCE_TYPE) | |
1114 | arg = adjust_temp_type (type, arg); | |
c8f6aeb1 | 1115 | if (!TREE_CONSTANT (arg)) |
1116 | *non_constant_args = true; | |
9c96033c | 1117 | *p = build_tree_list (parms, arg); |
1118 | p = &TREE_CHAIN (*p); | |
09b42213 | 1119 | next: |
1120 | parms = TREE_CHAIN (parms); | |
1121 | } | |
1122 | } | |
1123 | ||
1124 | /* Variables and functions to manage constexpr call expansion context. | |
1125 | These do not need to be marked for PCH or GC. */ | |
1126 | ||
1127 | /* FIXME remember and print actual constant arguments. */ | |
1128 | static vec<tree> call_stack = vNULL; | |
1129 | static int call_stack_tick; | |
1130 | static int last_cx_error_tick; | |
1131 | ||
1132 | static bool | |
1133 | push_cx_call_context (tree call) | |
1134 | { | |
1135 | ++call_stack_tick; | |
1136 | if (!EXPR_HAS_LOCATION (call)) | |
1137 | SET_EXPR_LOCATION (call, input_location); | |
1138 | call_stack.safe_push (call); | |
1139 | if (call_stack.length () > (unsigned) max_constexpr_depth) | |
1140 | return false; | |
1141 | return true; | |
1142 | } | |
1143 | ||
1144 | static void | |
1145 | pop_cx_call_context (void) | |
1146 | { | |
1147 | ++call_stack_tick; | |
1148 | call_stack.pop (); | |
1149 | } | |
1150 | ||
1151 | vec<tree> | |
1152 | cx_error_context (void) | |
1153 | { | |
1154 | vec<tree> r = vNULL; | |
1155 | if (call_stack_tick != last_cx_error_tick | |
1156 | && !call_stack.is_empty ()) | |
1157 | r = call_stack; | |
1158 | last_cx_error_tick = call_stack_tick; | |
1159 | return r; | |
1160 | } | |
1161 | ||
1162 | /* Subroutine of cxx_eval_constant_expression. | |
1163 | Evaluate the call expression tree T in the context of OLD_CALL expression | |
1164 | evaluation. */ | |
1165 | ||
1166 | static tree | |
cf72f34d | 1167 | cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1168 | bool lval, |
09b42213 | 1169 | bool *non_constant_p, bool *overflow_p) |
1170 | { | |
1171 | location_t loc = EXPR_LOC_OR_LOC (t, input_location); | |
1172 | tree fun = get_function_named_in_call (t); | |
09b42213 | 1173 | constexpr_call new_call = { NULL, NULL, NULL, 0 }; |
09b42213 | 1174 | bool depth_ok; |
1175 | ||
6b71bdb4 | 1176 | if (fun == NULL_TREE) |
1177 | switch (CALL_EXPR_IFN (t)) | |
1178 | { | |
1179 | case IFN_UBSAN_NULL: | |
1180 | case IFN_UBSAN_BOUNDS: | |
32cf7025 | 1181 | case IFN_UBSAN_VPTR: |
6b71bdb4 | 1182 | return void_node; |
1183 | default: | |
1184 | if (!ctx->quiet) | |
1185 | error_at (loc, "call to internal function"); | |
1186 | *non_constant_p = true; | |
1187 | return t; | |
1188 | } | |
1189 | ||
09b42213 | 1190 | if (TREE_CODE (fun) != FUNCTION_DECL) |
1191 | { | |
1192 | /* Might be a constexpr function pointer. */ | |
f83e6885 | 1193 | fun = cxx_eval_constant_expression (ctx, fun, |
1227ba74 | 1194 | /*lval*/false, non_constant_p, |
b2a43197 | 1195 | overflow_p); |
09b42213 | 1196 | STRIP_NOPS (fun); |
1197 | if (TREE_CODE (fun) == ADDR_EXPR) | |
1198 | fun = TREE_OPERAND (fun, 0); | |
1199 | } | |
1200 | if (TREE_CODE (fun) != FUNCTION_DECL) | |
1201 | { | |
f83e6885 | 1202 | if (!ctx->quiet && !*non_constant_p) |
09b42213 | 1203 | error_at (loc, "expression %qE does not designate a constexpr " |
1204 | "function", fun); | |
1205 | *non_constant_p = true; | |
1206 | return t; | |
1207 | } | |
1208 | if (DECL_CLONED_FUNCTION_P (fun)) | |
1209 | fun = DECL_CLONED_FUNCTION (fun); | |
6b71bdb4 | 1210 | |
1211 | if (is_ubsan_builtin_p (fun)) | |
1212 | return void_node; | |
1213 | ||
09b42213 | 1214 | if (is_builtin_fn (fun)) |
f1c6af10 | 1215 | return cxx_eval_builtin_function_call (ctx, t, fun, |
1227ba74 | 1216 | lval, non_constant_p, overflow_p); |
09b42213 | 1217 | if (!DECL_DECLARED_CONSTEXPR_P (fun)) |
1218 | { | |
f83e6885 | 1219 | if (!ctx->quiet) |
09b42213 | 1220 | { |
1221 | error_at (loc, "call to non-constexpr function %qD", fun); | |
1222 | explain_invalid_constexpr_fn (fun); | |
1223 | } | |
1224 | *non_constant_p = true; | |
1225 | return t; | |
1226 | } | |
1227 | ||
1228 | /* Shortcut trivial constructor/op=. */ | |
1229 | if (trivial_fn_p (fun)) | |
1230 | { | |
1231 | if (call_expr_nargs (t) == 2) | |
1232 | { | |
1233 | tree arg = convert_from_reference (get_nth_callarg (t, 1)); | |
f83e6885 | 1234 | return cxx_eval_constant_expression (ctx, arg, |
1227ba74 | 1235 | lval, non_constant_p, |
b2a43197 | 1236 | overflow_p); |
09b42213 | 1237 | } |
1238 | else if (TREE_CODE (t) == AGGR_INIT_EXPR | |
1239 | && AGGR_INIT_ZERO_FIRST (t)) | |
1240 | return build_zero_init (DECL_CONTEXT (fun), NULL_TREE, false); | |
1241 | } | |
1242 | ||
8afcf831 | 1243 | /* We can't defer instantiating the function any longer. */ |
1244 | if (!DECL_INITIAL (fun) | |
1245 | && DECL_TEMPLOID_INSTANTIATION (fun)) | |
1246 | { | |
1247 | ++function_depth; | |
1248 | instantiate_decl (fun, /*defer_ok*/false, /*expl_inst*/false); | |
1249 | --function_depth; | |
1250 | } | |
1251 | ||
09b42213 | 1252 | /* If in direct recursive call, optimize definition search. */ |
cf72f34d | 1253 | if (ctx && ctx->call && ctx->call->fundef->decl == fun) |
1254 | new_call.fundef = ctx->call->fundef; | |
09b42213 | 1255 | else |
1256 | { | |
1257 | new_call.fundef = retrieve_constexpr_fundef (fun); | |
1258 | if (new_call.fundef == NULL || new_call.fundef->body == NULL) | |
1259 | { | |
f83e6885 | 1260 | if (!ctx->quiet) |
09b42213 | 1261 | { |
1262 | if (DECL_INITIAL (fun)) | |
1263 | { | |
1264 | /* The definition of fun was somehow unsuitable. */ | |
1265 | error_at (loc, "%qD called in a constant expression", fun); | |
1266 | explain_invalid_constexpr_fn (fun); | |
1267 | } | |
1268 | else | |
1269 | error_at (loc, "%qD used before its definition", fun); | |
1270 | } | |
1271 | *non_constant_p = true; | |
1272 | return t; | |
1273 | } | |
1274 | } | |
9c96033c | 1275 | |
1276 | constexpr_ctx new_ctx = *ctx; | |
1277 | if (DECL_CONSTRUCTOR_P (fun) && !ctx->object | |
1278 | && TREE_CODE (t) == AGGR_INIT_EXPR) | |
1279 | { | |
1280 | /* We want to have an initialization target for an AGGR_INIT_EXPR. | |
1281 | If we don't already have one in CTX, use the AGGR_INIT_EXPR_SLOT. */ | |
1282 | new_ctx.object = AGGR_INIT_EXPR_SLOT (t); | |
1283 | tree ctor = new_ctx.ctor = build_constructor (DECL_CONTEXT (fun), NULL); | |
1284 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor) = true; | |
1285 | ctx->values->put (new_ctx.object, ctor); | |
1286 | ctx = &new_ctx; | |
1287 | } | |
1288 | ||
c8f6aeb1 | 1289 | bool non_constant_args = false; |
cf72f34d | 1290 | cxx_bind_parameters_in_call (ctx, t, &new_call, |
c8f6aeb1 | 1291 | non_constant_p, overflow_p, &non_constant_args); |
09b42213 | 1292 | if (*non_constant_p) |
1293 | return t; | |
1294 | ||
1295 | depth_ok = push_cx_call_context (t); | |
1296 | ||
c8f6aeb1 | 1297 | tree result = NULL_TREE; |
09b42213 | 1298 | |
c8f6aeb1 | 1299 | constexpr_call *entry = NULL; |
37715b0f | 1300 | if (depth_ok && !non_constant_args) |
09b42213 | 1301 | { |
c8f6aeb1 | 1302 | new_call.hash = iterative_hash_template_arg |
1303 | (new_call.bindings, constexpr_fundef_hasher::hash (new_call.fundef)); | |
1304 | ||
1305 | /* If we have seen this call before, we are done. */ | |
1306 | maybe_initialize_constexpr_call_table (); | |
1307 | constexpr_call **slot | |
1308 | = constexpr_call_table->find_slot (&new_call, INSERT); | |
1309 | entry = *slot; | |
1310 | if (entry == NULL) | |
1311 | { | |
1312 | /* We need to keep a pointer to the entry, not just the slot, as the | |
1313 | slot can move in the call to cxx_eval_builtin_function_call. */ | |
1314 | *slot = entry = ggc_alloc<constexpr_call> (); | |
1315 | *entry = new_call; | |
1316 | } | |
1317 | /* Calls which are in progress have their result set to NULL | |
1318 | so that we can detect circular dependencies. */ | |
1319 | else if (entry->result == NULL) | |
1320 | { | |
1321 | if (!ctx->quiet) | |
1322 | error ("call has circular dependency"); | |
1323 | *non_constant_p = true; | |
1324 | entry->result = result = error_mark_node; | |
1325 | } | |
1326 | else | |
1327 | result = entry->result; | |
09b42213 | 1328 | } |
1329 | ||
1330 | if (!depth_ok) | |
1331 | { | |
f83e6885 | 1332 | if (!ctx->quiet) |
09b42213 | 1333 | error ("constexpr evaluation depth exceeds maximum of %d (use " |
1334 | "-fconstexpr-depth= to increase the maximum)", | |
1335 | max_constexpr_depth); | |
1336 | *non_constant_p = true; | |
c8f6aeb1 | 1337 | result = error_mark_node; |
09b42213 | 1338 | } |
1339 | else | |
1340 | { | |
09b42213 | 1341 | if (!result || result == error_mark_node) |
cf72f34d | 1342 | { |
88a59139 | 1343 | if (DECL_SAVED_TREE (fun) == NULL_TREE |
1344 | && (DECL_CONSTRUCTOR_P (fun) || DECL_DESTRUCTOR_P (fun))) | |
1345 | /* The maybe-in-charge 'tor had its DECL_SAVED_TREE | |
1346 | cleared, try a clone. */ | |
1347 | for (fun = DECL_CHAIN (fun); | |
1348 | fun && DECL_CLONED_FUNCTION_P (fun); | |
1349 | fun = DECL_CHAIN (fun)) | |
1350 | if (DECL_SAVED_TREE (fun)) | |
1351 | break; | |
1352 | gcc_assert (DECL_SAVED_TREE (fun)); | |
1353 | tree parms, res; | |
1354 | ||
1355 | /* Unshare the whole function body. */ | |
1356 | tree body = copy_fn (fun, parms, res); | |
1357 | ||
1358 | /* Associate the bindings with the remapped parms. */ | |
1359 | tree bound = new_call.bindings; | |
1360 | tree remapped = parms; | |
1361 | while (bound) | |
9c96033c | 1362 | { |
88a59139 | 1363 | tree oparm = TREE_PURPOSE (bound); |
1364 | tree arg = TREE_VALUE (bound); | |
1365 | gcc_assert (DECL_NAME (remapped) == DECL_NAME (oparm)); | |
1366 | ctx->values->put (remapped, arg); | |
1367 | bound = TREE_CHAIN (bound); | |
1368 | remapped = DECL_CHAIN (remapped); | |
9c96033c | 1369 | } |
88a59139 | 1370 | /* Add the RESULT_DECL to the values map, too. */ |
1371 | tree slot = NULL_TREE; | |
1372 | if (DECL_BY_REFERENCE (res)) | |
9c96033c | 1373 | { |
88a59139 | 1374 | slot = AGGR_INIT_EXPR_SLOT (t); |
1375 | tree addr = build_address (slot); | |
1376 | addr = build_nop (TREE_TYPE (res), addr); | |
1377 | ctx->values->put (res, addr); | |
1378 | ctx->values->put (slot, NULL_TREE); | |
1379 | } | |
1380 | else | |
1381 | ctx->values->put (res, NULL_TREE); | |
9c96033c | 1382 | |
88a59139 | 1383 | tree jump_target = NULL_TREE; |
1384 | cxx_eval_constant_expression (ctx, body, | |
1385 | lval, non_constant_p, overflow_p, | |
1386 | &jump_target); | |
9c96033c | 1387 | |
88a59139 | 1388 | if (DECL_CONSTRUCTOR_P (fun)) |
1389 | /* This can be null for a subobject constructor call, in | |
1390 | which case what we care about is the initialization | |
1391 | side-effects rather than the value. We could get at the | |
1392 | value by evaluating *this, but we don't bother; there's | |
1393 | no need to put such a call in the hash table. */ | |
1394 | result = lval ? ctx->object : ctx->ctor; | |
1395 | else if (VOID_TYPE_P (TREE_TYPE (res))) | |
1396 | result = void_node; | |
1397 | else | |
1398 | { | |
1399 | result = *ctx->values->get (slot ? slot : res); | |
1400 | if (result == NULL_TREE && !*non_constant_p) | |
9c96033c | 1401 | { |
88a59139 | 1402 | if (!ctx->quiet) |
1403 | error ("constexpr call flows off the end " | |
1404 | "of the function"); | |
1405 | *non_constant_p = true; | |
9c96033c | 1406 | } |
9c96033c | 1407 | } |
88a59139 | 1408 | |
1409 | /* Remove the parms/result from the values map. Is it worth | |
1410 | bothering to do this when the map itself is only live for | |
1411 | one constexpr evaluation? If so, maybe also clear out | |
1412 | other vars from call, maybe in BIND_EXPR handling? */ | |
1413 | ctx->values->remove (res); | |
1414 | if (slot) | |
1415 | ctx->values->remove (slot); | |
1416 | for (tree parm = parms; parm; parm = TREE_CHAIN (parm)) | |
1417 | ctx->values->remove (parm); | |
cf72f34d | 1418 | } |
9c96033c | 1419 | |
09b42213 | 1420 | if (result == error_mark_node) |
1421 | *non_constant_p = true; | |
1422 | if (*non_constant_p) | |
c8f6aeb1 | 1423 | result = error_mark_node; |
88a59139 | 1424 | else if (!result) |
9c96033c | 1425 | result = void_node; |
c8f6aeb1 | 1426 | if (entry) |
1427 | entry->result = result; | |
09b42213 | 1428 | } |
1429 | ||
1430 | pop_cx_call_context (); | |
1431 | return unshare_expr (result); | |
1432 | } | |
1433 | ||
1434 | /* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */ | |
1435 | ||
1436 | bool | |
1437 | reduced_constant_expression_p (tree t) | |
1438 | { | |
1439 | switch (TREE_CODE (t)) | |
1440 | { | |
1441 | case PTRMEM_CST: | |
1442 | /* Even if we can't lower this yet, it's constant. */ | |
1443 | return true; | |
1444 | ||
1445 | case CONSTRUCTOR: | |
1446 | /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */ | |
1447 | tree elt; unsigned HOST_WIDE_INT idx; | |
1448 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), idx, elt) | |
1449 | if (!reduced_constant_expression_p (elt)) | |
1450 | return false; | |
1451 | return true; | |
1452 | ||
1453 | default: | |
1454 | /* FIXME are we calling this too much? */ | |
1455 | return initializer_constant_valid_p (t, TREE_TYPE (t)) != NULL_TREE; | |
1456 | } | |
1457 | } | |
1458 | ||
1459 | /* Some expressions may have constant operands but are not constant | |
1460 | themselves, such as 1/0. Call this function (or rather, the macro | |
1461 | following it) to check for that condition. | |
1462 | ||
1463 | We only call this in places that require an arithmetic constant, not in | |
1464 | places where we might have a non-constant expression that can be a | |
1465 | component of a constant expression, such as the address of a constexpr | |
1466 | variable that might be dereferenced later. */ | |
1467 | ||
1468 | static bool | |
1469 | verify_constant (tree t, bool allow_non_constant, bool *non_constant_p, | |
1470 | bool *overflow_p) | |
1471 | { | |
1472 | if (!*non_constant_p && !reduced_constant_expression_p (t)) | |
1473 | { | |
1474 | if (!allow_non_constant) | |
1475 | error ("%q+E is not a constant expression", t); | |
1476 | *non_constant_p = true; | |
1477 | } | |
1478 | if (TREE_OVERFLOW_P (t)) | |
1479 | { | |
1480 | if (!allow_non_constant) | |
1481 | { | |
1482 | permerror (input_location, "overflow in constant expression"); | |
1483 | /* If we're being permissive (and are in an enforcing | |
1484 | context), ignore the overflow. */ | |
1485 | if (flag_permissive) | |
1486 | return *non_constant_p; | |
1487 | } | |
1488 | *overflow_p = true; | |
1489 | } | |
1490 | return *non_constant_p; | |
1491 | } | |
1492 | ||
2b035ffe | 1493 | /* Check whether the shift operation with code CODE and type TYPE on LHS |
1494 | and RHS is undefined. If it is, give an error with an explanation, | |
1495 | and return true; return false otherwise. */ | |
1496 | ||
1497 | static bool | |
1498 | cxx_eval_check_shift_p (location_t loc, const constexpr_ctx *ctx, | |
1499 | enum tree_code code, tree type, tree lhs, tree rhs) | |
1500 | { | |
1501 | if ((code != LSHIFT_EXPR && code != RSHIFT_EXPR) | |
1502 | || TREE_CODE (lhs) != INTEGER_CST | |
1503 | || TREE_CODE (rhs) != INTEGER_CST) | |
1504 | return false; | |
1505 | ||
1506 | tree lhstype = TREE_TYPE (lhs); | |
1507 | unsigned HOST_WIDE_INT uprec = TYPE_PRECISION (TREE_TYPE (lhs)); | |
1508 | ||
1509 | /* [expr.shift] The behavior is undefined if the right operand | |
1510 | is negative, or greater than or equal to the length in bits | |
1511 | of the promoted left operand. */ | |
1512 | if (tree_int_cst_sgn (rhs) == -1) | |
1513 | { | |
1514 | if (!ctx->quiet) | |
91d87e22 | 1515 | permerror (loc, "right operand of shift expression %q+E is negative", |
1516 | build2_loc (loc, code, type, lhs, rhs)); | |
1517 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1518 | } |
1519 | if (compare_tree_int (rhs, uprec) >= 0) | |
1520 | { | |
1521 | if (!ctx->quiet) | |
91d87e22 | 1522 | permerror (loc, "right operand of shift expression %q+E is >= than " |
1523 | "the precision of the left operand", | |
1524 | build2_loc (loc, code, type, lhs, rhs)); | |
1525 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1526 | } |
1527 | ||
1528 | /* The value of E1 << E2 is E1 left-shifted E2 bit positions; [...] | |
1529 | if E1 has a signed type and non-negative value, and E1x2^E2 is | |
1530 | representable in the corresponding unsigned type of the result type, | |
1531 | then that value, converted to the result type, is the resulting value; | |
1532 | otherwise, the behavior is undefined. */ | |
1533 | if (code == LSHIFT_EXPR && !TYPE_UNSIGNED (lhstype) | |
1534 | && (cxx_dialect >= cxx11)) | |
1535 | { | |
1536 | if (tree_int_cst_sgn (lhs) == -1) | |
1537 | { | |
1538 | if (!ctx->quiet) | |
91d87e22 | 1539 | permerror (loc, |
1540 | "left operand of shift expression %q+E is negative", | |
1541 | build2_loc (loc, code, type, lhs, rhs)); | |
1542 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1543 | } |
1544 | /* For signed x << y the following: | |
1545 | (unsigned) x >> ((prec (lhs) - 1) - y) | |
1546 | if > 1, is undefined. The right-hand side of this formula | |
1547 | is the highest bit of the LHS that can be set (starting from 0), | |
1548 | so that the shift doesn't overflow. We then right-shift the LHS | |
1549 | to see whether any other bit is set making the original shift | |
1550 | undefined -- the result is not representable in the corresponding | |
1551 | unsigned type. */ | |
1552 | tree t = build_int_cst (unsigned_type_node, uprec - 1); | |
1553 | t = fold_build2 (MINUS_EXPR, unsigned_type_node, t, rhs); | |
1554 | tree ulhs = fold_convert (unsigned_type_for (lhstype), lhs); | |
1555 | t = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ulhs), ulhs, t); | |
1556 | if (tree_int_cst_lt (integer_one_node, t)) | |
1557 | { | |
1558 | if (!ctx->quiet) | |
91d87e22 | 1559 | permerror (loc, "shift expression %q+E overflows", |
1560 | build2_loc (loc, code, type, lhs, rhs)); | |
1561 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1562 | } |
1563 | } | |
1564 | return false; | |
1565 | } | |
1566 | ||
09b42213 | 1567 | /* Subroutine of cxx_eval_constant_expression. |
1568 | Attempt to reduce the unary expression tree T to a compile time value. | |
1569 | If successful, return the value. Otherwise issue a diagnostic | |
1570 | and return error_mark_node. */ | |
1571 | ||
1572 | static tree | |
cf72f34d | 1573 | cxx_eval_unary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 1574 | bool /*lval*/, |
09b42213 | 1575 | bool *non_constant_p, bool *overflow_p) |
1576 | { | |
1577 | tree r; | |
1578 | tree orig_arg = TREE_OPERAND (t, 0); | |
c8f6aeb1 | 1579 | tree arg = cxx_eval_constant_expression (ctx, orig_arg, /*lval*/false, |
1580 | non_constant_p, overflow_p); | |
09b42213 | 1581 | VERIFY_CONSTANT (arg); |
93add516 | 1582 | location_t loc = EXPR_LOCATION (t); |
1583 | enum tree_code code = TREE_CODE (t); | |
1584 | tree type = TREE_TYPE (t); | |
1585 | r = fold_unary_loc (loc, code, type, arg); | |
1586 | if (r == NULL_TREE) | |
1587 | { | |
1588 | if (arg == orig_arg) | |
1589 | r = t; | |
1590 | else | |
1591 | r = build1_loc (loc, code, type, arg); | |
1592 | } | |
09b42213 | 1593 | VERIFY_CONSTANT (r); |
1594 | return r; | |
1595 | } | |
1596 | ||
1597 | /* Subroutine of cxx_eval_constant_expression. | |
1598 | Like cxx_eval_unary_expression, except for binary expressions. */ | |
1599 | ||
1600 | static tree | |
cf72f34d | 1601 | cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 1602 | bool /*lval*/, |
09b42213 | 1603 | bool *non_constant_p, bool *overflow_p) |
1604 | { | |
1605 | tree r; | |
1606 | tree orig_lhs = TREE_OPERAND (t, 0); | |
1607 | tree orig_rhs = TREE_OPERAND (t, 1); | |
1608 | tree lhs, rhs; | |
c8f6aeb1 | 1609 | lhs = cxx_eval_constant_expression (ctx, orig_lhs, /*lval*/false, |
b2a43197 | 1610 | non_constant_p, overflow_p); |
35f2c28f | 1611 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
1612 | a local array in a constexpr function. */ | |
1613 | bool ptr = POINTER_TYPE_P (TREE_TYPE (lhs)); | |
1614 | if (!ptr) | |
1615 | VERIFY_CONSTANT (lhs); | |
c8f6aeb1 | 1616 | rhs = cxx_eval_constant_expression (ctx, orig_rhs, /*lval*/false, |
b2a43197 | 1617 | non_constant_p, overflow_p); |
35f2c28f | 1618 | if (!ptr) |
aae7465c | 1619 | VERIFY_CONSTANT (rhs); |
93add516 | 1620 | |
1621 | location_t loc = EXPR_LOCATION (t); | |
1622 | enum tree_code code = TREE_CODE (t); | |
1623 | tree type = TREE_TYPE (t); | |
1624 | r = fold_binary_loc (loc, code, type, lhs, rhs); | |
1625 | if (r == NULL_TREE) | |
1626 | { | |
1627 | if (lhs == orig_lhs && rhs == orig_rhs) | |
1628 | r = t; | |
1629 | else | |
1630 | r = build2_loc (loc, code, type, lhs, rhs); | |
1631 | } | |
2b035ffe | 1632 | else if (cxx_eval_check_shift_p (loc, ctx, code, type, lhs, rhs)) |
1633 | *non_constant_p = true; | |
35f2c28f | 1634 | if (!ptr) |
aae7465c | 1635 | VERIFY_CONSTANT (r); |
09b42213 | 1636 | return r; |
1637 | } | |
1638 | ||
1639 | /* Subroutine of cxx_eval_constant_expression. | |
1640 | Attempt to evaluate condition expressions. Dead branches are not | |
1641 | looked into. */ | |
1642 | ||
1643 | static tree | |
cf72f34d | 1644 | cxx_eval_conditional_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1645 | bool lval, |
00f21715 | 1646 | bool *non_constant_p, bool *overflow_p, |
1647 | tree *jump_target) | |
09b42213 | 1648 | { |
cf72f34d | 1649 | tree val = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
c8f6aeb1 | 1650 | /*lval*/false, |
b2a43197 | 1651 | non_constant_p, overflow_p); |
09b42213 | 1652 | VERIFY_CONSTANT (val); |
1653 | /* Don't VERIFY_CONSTANT the other operands. */ | |
1654 | if (integer_zerop (val)) | |
cf72f34d | 1655 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), |
1227ba74 | 1656 | lval, |
00f21715 | 1657 | non_constant_p, overflow_p, |
1658 | jump_target); | |
cf72f34d | 1659 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 1660 | lval, |
00f21715 | 1661 | non_constant_p, overflow_p, |
1662 | jump_target); | |
09b42213 | 1663 | } |
1664 | ||
7963b19d | 1665 | /* Returns less than, equal to, or greater than zero if KEY is found to be |
1666 | less than, to match, or to be greater than the constructor_elt's INDEX. */ | |
1667 | ||
1668 | static int | |
1669 | array_index_cmp (tree key, tree index) | |
1670 | { | |
1671 | gcc_assert (TREE_CODE (key) == INTEGER_CST); | |
1672 | ||
1673 | switch (TREE_CODE (index)) | |
1674 | { | |
1675 | case INTEGER_CST: | |
1676 | return tree_int_cst_compare (key, index); | |
1677 | case RANGE_EXPR: | |
1678 | { | |
1679 | tree lo = TREE_OPERAND (index, 0); | |
1680 | tree hi = TREE_OPERAND (index, 1); | |
1681 | if (tree_int_cst_lt (key, lo)) | |
1682 | return -1; | |
1683 | else if (tree_int_cst_lt (hi, key)) | |
1684 | return 1; | |
1685 | else | |
1686 | return 0; | |
1687 | } | |
1688 | default: | |
1689 | gcc_unreachable (); | |
1690 | } | |
1691 | } | |
1692 | ||
1693 | /* Returns the index of the constructor_elt of ARY which matches DINDEX, or -1 | |
1694 | if none. If INSERT is true, insert a matching element rather than fail. */ | |
1695 | ||
1696 | static HOST_WIDE_INT | |
1697 | find_array_ctor_elt (tree ary, tree dindex, bool insert = false) | |
1698 | { | |
1699 | if (tree_int_cst_sgn (dindex) < 0) | |
1700 | return -1; | |
1701 | ||
1702 | unsigned HOST_WIDE_INT i = tree_to_uhwi (dindex); | |
1703 | vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (ary); | |
1704 | unsigned HOST_WIDE_INT len = vec_safe_length (elts); | |
1705 | ||
1706 | unsigned HOST_WIDE_INT end = len; | |
1707 | unsigned HOST_WIDE_INT begin = 0; | |
1708 | ||
1709 | /* If the last element of the CONSTRUCTOR has its own index, we can assume | |
1710 | that the same is true of the other elements and index directly. */ | |
1711 | if (end > 0) | |
1712 | { | |
1713 | tree cindex = (*elts)[end-1].index; | |
1714 | if (TREE_CODE (cindex) == INTEGER_CST | |
1715 | && compare_tree_int (cindex, end-1) == 0) | |
1716 | { | |
1717 | if (i < end) | |
1718 | return i; | |
1719 | else | |
1720 | begin = end; | |
1721 | } | |
1722 | } | |
1723 | ||
1724 | /* Otherwise, find a matching index by means of a binary search. */ | |
1725 | while (begin != end) | |
1726 | { | |
1727 | unsigned HOST_WIDE_INT middle = (begin + end) / 2; | |
f0b916c7 | 1728 | constructor_elt &elt = (*elts)[middle]; |
1729 | tree idx = elt.index; | |
7963b19d | 1730 | |
f0b916c7 | 1731 | int cmp = array_index_cmp (dindex, idx); |
7963b19d | 1732 | if (cmp < 0) |
1733 | end = middle; | |
1734 | else if (cmp > 0) | |
1735 | begin = middle + 1; | |
1736 | else | |
f0b916c7 | 1737 | { |
1738 | if (insert && TREE_CODE (idx) == RANGE_EXPR) | |
1739 | { | |
1740 | /* We need to split the range. */ | |
1741 | constructor_elt e; | |
1742 | tree lo = TREE_OPERAND (idx, 0); | |
1743 | tree hi = TREE_OPERAND (idx, 1); | |
1744 | if (tree_int_cst_lt (lo, dindex)) | |
1745 | { | |
1746 | /* There are still some lower elts; shorten the range. */ | |
1747 | tree new_hi = int_const_binop (MINUS_EXPR, dindex, | |
1748 | size_one_node); | |
1749 | if (tree_int_cst_equal (lo, new_hi)) | |
1750 | /* Only one element left, no longer a range. */ | |
1751 | elt.index = lo; | |
1752 | else | |
1753 | TREE_OPERAND (idx, 1) = new_hi; | |
1754 | /* Append the element we want to insert. */ | |
1755 | ++middle; | |
1756 | e.index = dindex; | |
1757 | e.value = unshare_expr (elt.value); | |
1758 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle, e); | |
1759 | } | |
1760 | else | |
1761 | /* No lower elts, the range elt is now ours. */ | |
1762 | elt.index = dindex; | |
1763 | ||
1764 | if (tree_int_cst_lt (dindex, hi)) | |
1765 | { | |
1766 | /* There are still some higher elts; append a range. */ | |
1767 | tree new_lo = int_const_binop (PLUS_EXPR, dindex, | |
1768 | size_one_node); | |
1769 | if (tree_int_cst_equal (new_lo, hi)) | |
1770 | e.index = hi; | |
1771 | else | |
1772 | e.index = build2 (RANGE_EXPR, sizetype, new_lo, hi); | |
1773 | e.value = unshare_expr (elt.value); | |
1774 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle+1, e); | |
1775 | } | |
1776 | } | |
1777 | return middle; | |
1778 | } | |
7963b19d | 1779 | } |
1780 | ||
1781 | if (insert) | |
1782 | { | |
1783 | constructor_elt e = { dindex, NULL_TREE }; | |
1784 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), end, e); | |
1785 | return end; | |
1786 | } | |
1787 | ||
1788 | return -1; | |
1789 | } | |
1790 | ||
1791 | ||
09b42213 | 1792 | /* Subroutine of cxx_eval_constant_expression. |
1793 | Attempt to reduce a reference to an array slot. */ | |
1794 | ||
1795 | static tree | |
cf72f34d | 1796 | cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1797 | bool lval, |
09b42213 | 1798 | bool *non_constant_p, bool *overflow_p) |
1799 | { | |
1800 | tree oldary = TREE_OPERAND (t, 0); | |
cf72f34d | 1801 | tree ary = cxx_eval_constant_expression (ctx, oldary, |
1227ba74 | 1802 | lval, |
b2a43197 | 1803 | non_constant_p, overflow_p); |
09b42213 | 1804 | tree index, oldidx; |
1805 | HOST_WIDE_INT i; | |
1806 | tree elem_type; | |
1807 | unsigned len, elem_nchars = 1; | |
1808 | if (*non_constant_p) | |
1809 | return t; | |
1810 | oldidx = TREE_OPERAND (t, 1); | |
cf72f34d | 1811 | index = cxx_eval_constant_expression (ctx, oldidx, |
f83e6885 | 1812 | false, |
b2a43197 | 1813 | non_constant_p, overflow_p); |
09b42213 | 1814 | VERIFY_CONSTANT (index); |
1227ba74 | 1815 | if (lval && ary == oldary && index == oldidx) |
09b42213 | 1816 | return t; |
1227ba74 | 1817 | else if (lval) |
09b42213 | 1818 | return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL); |
1819 | elem_type = TREE_TYPE (TREE_TYPE (ary)); | |
1820 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
1821 | len = CONSTRUCTOR_NELTS (ary); | |
1822 | else if (TREE_CODE (ary) == STRING_CST) | |
1823 | { | |
1824 | elem_nchars = (TYPE_PRECISION (elem_type) | |
1825 | / TYPE_PRECISION (char_type_node)); | |
1826 | len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars; | |
1827 | } | |
1828 | else | |
1829 | { | |
1830 | /* We can't do anything with other tree codes, so use | |
1831 | VERIFY_CONSTANT to complain and fail. */ | |
1832 | VERIFY_CONSTANT (ary); | |
1833 | gcc_unreachable (); | |
1834 | } | |
aed8dc7f | 1835 | |
f6b30463 | 1836 | if (!tree_fits_shwi_p (index) |
1837 | || (i = tree_to_shwi (index)) < 0) | |
7963b19d | 1838 | { |
1839 | if (!ctx->quiet) | |
1840 | error ("negative array subscript"); | |
1841 | *non_constant_p = true; | |
1842 | return t; | |
1843 | } | |
1844 | ||
1845 | bool found; | |
1846 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
1847 | { | |
1848 | HOST_WIDE_INT ix = find_array_ctor_elt (ary, index); | |
1849 | found = (ix >= 0); | |
1850 | if (found) | |
1851 | i = ix; | |
aed8dc7f | 1852 | } |
7963b19d | 1853 | else |
1854 | found = (i < len); | |
aed8dc7f | 1855 | |
7963b19d | 1856 | if (!found) |
09b42213 | 1857 | { |
1858 | if (tree_int_cst_lt (index, array_type_nelts_top (TREE_TYPE (ary)))) | |
1859 | { | |
a02b42fe | 1860 | if (TREE_CODE (ary) == CONSTRUCTOR |
1861 | && CONSTRUCTOR_NO_IMPLICIT_ZERO (ary)) | |
1862 | { | |
1863 | /* 'ary' is part of the aggregate initializer we're currently | |
1864 | building; if there's no initializer for this element yet, | |
1865 | that's an error. */ | |
1866 | if (!ctx->quiet) | |
1867 | error ("accessing uninitialized array element"); | |
1868 | *non_constant_p = true; | |
1869 | return t; | |
1870 | } | |
1871 | ||
09b42213 | 1872 | /* If it's within the array bounds but doesn't have an explicit |
1873 | initializer, it's value-initialized. */ | |
1874 | tree val = build_value_init (elem_type, tf_warning_or_error); | |
cf72f34d | 1875 | return cxx_eval_constant_expression (ctx, val, |
1227ba74 | 1876 | lval, |
b2a43197 | 1877 | non_constant_p, overflow_p); |
09b42213 | 1878 | } |
1879 | ||
f83e6885 | 1880 | if (!ctx->quiet) |
09b42213 | 1881 | error ("array subscript out of bound"); |
1882 | *non_constant_p = true; | |
1883 | return t; | |
1884 | } | |
aed8dc7f | 1885 | |
09b42213 | 1886 | if (TREE_CODE (ary) == CONSTRUCTOR) |
1887 | return (*CONSTRUCTOR_ELTS (ary))[i].value; | |
1888 | else if (elem_nchars == 1) | |
1889 | return build_int_cst (cv_unqualified (TREE_TYPE (TREE_TYPE (ary))), | |
1890 | TREE_STRING_POINTER (ary)[i]); | |
1891 | else | |
1892 | { | |
1893 | tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (ary))); | |
1894 | return native_interpret_expr (type, (const unsigned char *) | |
1895 | TREE_STRING_POINTER (ary) | |
1896 | + i * elem_nchars, elem_nchars); | |
1897 | } | |
1898 | /* Don't VERIFY_CONSTANT here. */ | |
1899 | } | |
1900 | ||
1901 | /* Subroutine of cxx_eval_constant_expression. | |
1902 | Attempt to reduce a field access of a value of class type. */ | |
1903 | ||
1904 | static tree | |
cf72f34d | 1905 | cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1906 | bool lval, |
09b42213 | 1907 | bool *non_constant_p, bool *overflow_p) |
1908 | { | |
1909 | unsigned HOST_WIDE_INT i; | |
1910 | tree field; | |
1911 | tree value; | |
1912 | tree part = TREE_OPERAND (t, 1); | |
1913 | tree orig_whole = TREE_OPERAND (t, 0); | |
cf72f34d | 1914 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 1915 | lval, |
b2a43197 | 1916 | non_constant_p, overflow_p); |
f16ed232 | 1917 | if (TREE_CODE (whole) == PTRMEM_CST) |
1918 | whole = cplus_expand_constant (whole); | |
09b42213 | 1919 | if (whole == orig_whole) |
1920 | return t; | |
1227ba74 | 1921 | if (lval) |
09b42213 | 1922 | return fold_build3 (COMPONENT_REF, TREE_TYPE (t), |
1923 | whole, part, NULL_TREE); | |
1924 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
1925 | CONSTRUCTOR. */ | |
1926 | if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR) | |
1927 | { | |
f83e6885 | 1928 | if (!ctx->quiet) |
09b42213 | 1929 | error ("%qE is not a constant expression", orig_whole); |
1930 | *non_constant_p = true; | |
1931 | } | |
1932 | if (DECL_MUTABLE_P (part)) | |
1933 | { | |
f83e6885 | 1934 | if (!ctx->quiet) |
09b42213 | 1935 | error ("mutable %qD is not usable in a constant expression", part); |
1936 | *non_constant_p = true; | |
1937 | } | |
1938 | if (*non_constant_p) | |
1939 | return t; | |
1940 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
1941 | { | |
1942 | if (field == part) | |
9c96033c | 1943 | { |
1944 | if (value) | |
1945 | return value; | |
1946 | else | |
1947 | /* We're in the middle of initializing it. */ | |
1948 | break; | |
1949 | } | |
09b42213 | 1950 | } |
1951 | if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE | |
1952 | && CONSTRUCTOR_NELTS (whole) > 0) | |
1953 | { | |
1954 | /* DR 1188 says we don't have to deal with this. */ | |
f83e6885 | 1955 | if (!ctx->quiet) |
09b42213 | 1956 | error ("accessing %qD member instead of initialized %qD member in " |
1957 | "constant expression", part, CONSTRUCTOR_ELT (whole, 0)->index); | |
1958 | *non_constant_p = true; | |
1959 | return t; | |
1960 | } | |
1961 | ||
cf72f34d | 1962 | if (CONSTRUCTOR_NO_IMPLICIT_ZERO (whole)) |
1963 | { | |
1964 | /* 'whole' is part of the aggregate initializer we're currently | |
1965 | building; if there's no initializer for this member yet, that's an | |
1966 | error. */ | |
f83e6885 | 1967 | if (!ctx->quiet) |
cf72f34d | 1968 | error ("accessing uninitialized member %qD", part); |
1969 | *non_constant_p = true; | |
1970 | return t; | |
1971 | } | |
1972 | ||
09b42213 | 1973 | /* If there's no explicit init for this field, it's value-initialized. */ |
1974 | value = build_value_init (TREE_TYPE (t), tf_warning_or_error); | |
cf72f34d | 1975 | return cxx_eval_constant_expression (ctx, value, |
1227ba74 | 1976 | lval, |
b2a43197 | 1977 | non_constant_p, overflow_p); |
09b42213 | 1978 | } |
1979 | ||
1980 | /* Subroutine of cxx_eval_constant_expression. | |
1981 | Attempt to reduce a field access of a value of class type that is | |
1982 | expressed as a BIT_FIELD_REF. */ | |
1983 | ||
1984 | static tree | |
cf72f34d | 1985 | cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1986 | bool lval, |
09b42213 | 1987 | bool *non_constant_p, bool *overflow_p) |
1988 | { | |
1989 | tree orig_whole = TREE_OPERAND (t, 0); | |
1990 | tree retval, fldval, utype, mask; | |
1991 | bool fld_seen = false; | |
1992 | HOST_WIDE_INT istart, isize; | |
cf72f34d | 1993 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 1994 | lval, |
b2a43197 | 1995 | non_constant_p, overflow_p); |
09b42213 | 1996 | tree start, field, value; |
1997 | unsigned HOST_WIDE_INT i; | |
1998 | ||
1999 | if (whole == orig_whole) | |
2000 | return t; | |
2001 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2002 | CONSTRUCTOR. */ | |
2003 | if (!*non_constant_p | |
2004 | && TREE_CODE (whole) != VECTOR_CST | |
2005 | && TREE_CODE (whole) != CONSTRUCTOR) | |
2006 | { | |
f83e6885 | 2007 | if (!ctx->quiet) |
09b42213 | 2008 | error ("%qE is not a constant expression", orig_whole); |
2009 | *non_constant_p = true; | |
2010 | } | |
2011 | if (*non_constant_p) | |
2012 | return t; | |
2013 | ||
2014 | if (TREE_CODE (whole) == VECTOR_CST) | |
2015 | return fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole, | |
2016 | TREE_OPERAND (t, 1), TREE_OPERAND (t, 2)); | |
2017 | ||
2018 | start = TREE_OPERAND (t, 2); | |
2019 | istart = tree_to_shwi (start); | |
2020 | isize = tree_to_shwi (TREE_OPERAND (t, 1)); | |
2021 | utype = TREE_TYPE (t); | |
2022 | if (!TYPE_UNSIGNED (utype)) | |
2023 | utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1); | |
2024 | retval = build_int_cst (utype, 0); | |
2025 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
2026 | { | |
2027 | tree bitpos = bit_position (field); | |
2028 | if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1)) | |
2029 | return value; | |
2030 | if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE | |
2031 | && TREE_CODE (value) == INTEGER_CST | |
2032 | && tree_fits_shwi_p (bitpos) | |
2033 | && tree_fits_shwi_p (DECL_SIZE (field))) | |
2034 | { | |
2035 | HOST_WIDE_INT bit = tree_to_shwi (bitpos); | |
2036 | HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field)); | |
2037 | HOST_WIDE_INT shift; | |
2038 | if (bit >= istart && bit + sz <= istart + isize) | |
2039 | { | |
2040 | fldval = fold_convert (utype, value); | |
2041 | mask = build_int_cst_type (utype, -1); | |
2042 | mask = fold_build2 (LSHIFT_EXPR, utype, mask, | |
2043 | size_int (TYPE_PRECISION (utype) - sz)); | |
2044 | mask = fold_build2 (RSHIFT_EXPR, utype, mask, | |
2045 | size_int (TYPE_PRECISION (utype) - sz)); | |
2046 | fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask); | |
2047 | shift = bit - istart; | |
2048 | if (BYTES_BIG_ENDIAN) | |
2049 | shift = TYPE_PRECISION (utype) - shift - sz; | |
2050 | fldval = fold_build2 (LSHIFT_EXPR, utype, fldval, | |
2051 | size_int (shift)); | |
2052 | retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval); | |
2053 | fld_seen = true; | |
2054 | } | |
2055 | } | |
2056 | } | |
2057 | if (fld_seen) | |
2058 | return fold_convert (TREE_TYPE (t), retval); | |
2059 | gcc_unreachable (); | |
2060 | return error_mark_node; | |
2061 | } | |
2062 | ||
2063 | /* Subroutine of cxx_eval_constant_expression. | |
2064 | Evaluate a short-circuited logical expression T in the context | |
2065 | of a given constexpr CALL. BAILOUT_VALUE is the value for | |
2066 | early return. CONTINUE_VALUE is used here purely for | |
2067 | sanity check purposes. */ | |
2068 | ||
2069 | static tree | |
cf72f34d | 2070 | cxx_eval_logical_expression (const constexpr_ctx *ctx, tree t, |
09b42213 | 2071 | tree bailout_value, tree continue_value, |
1227ba74 | 2072 | bool lval, |
09b42213 | 2073 | bool *non_constant_p, bool *overflow_p) |
2074 | { | |
2075 | tree r; | |
cf72f34d | 2076 | tree lhs = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 2077 | lval, |
b2a43197 | 2078 | non_constant_p, overflow_p); |
09b42213 | 2079 | VERIFY_CONSTANT (lhs); |
2080 | if (tree_int_cst_equal (lhs, bailout_value)) | |
2081 | return lhs; | |
2082 | gcc_assert (tree_int_cst_equal (lhs, continue_value)); | |
cf72f34d | 2083 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2084 | lval, non_constant_p, |
b2a43197 | 2085 | overflow_p); |
09b42213 | 2086 | VERIFY_CONSTANT (r); |
2087 | return r; | |
2088 | } | |
2089 | ||
2090 | /* REF is a COMPONENT_REF designating a particular field. V is a vector of | |
2091 | CONSTRUCTOR elements to initialize (part of) an object containing that | |
2092 | field. Return a pointer to the constructor_elt corresponding to the | |
2093 | initialization of the field. */ | |
2094 | ||
2095 | static constructor_elt * | |
2096 | base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref) | |
2097 | { | |
2098 | tree aggr = TREE_OPERAND (ref, 0); | |
2099 | tree field = TREE_OPERAND (ref, 1); | |
2100 | HOST_WIDE_INT i; | |
2101 | constructor_elt *ce; | |
2102 | ||
2103 | gcc_assert (TREE_CODE (ref) == COMPONENT_REF); | |
2104 | ||
2105 | if (TREE_CODE (aggr) == COMPONENT_REF) | |
2106 | { | |
2107 | constructor_elt *base_ce | |
2108 | = base_field_constructor_elt (v, aggr); | |
2109 | v = CONSTRUCTOR_ELTS (base_ce->value); | |
2110 | } | |
2111 | ||
2112 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2113 | if (ce->index == field) | |
2114 | return ce; | |
2115 | ||
2116 | gcc_unreachable (); | |
2117 | return NULL; | |
2118 | } | |
2119 | ||
cf72f34d | 2120 | /* Some of the expressions fed to the constexpr mechanism are calls to |
2121 | constructors, which have type void. In that case, return the type being | |
2122 | initialized by the constructor. */ | |
2123 | ||
2124 | static tree | |
2125 | initialized_type (tree t) | |
2126 | { | |
2127 | if (TYPE_P (t)) | |
2128 | return t; | |
2129 | tree type = cv_unqualified (TREE_TYPE (t)); | |
2130 | if (TREE_CODE (t) == CALL_EXPR || TREE_CODE (t) == AGGR_INIT_EXPR) | |
2131 | { | |
2132 | /* A constructor call has void type, so we need to look deeper. */ | |
2133 | tree fn = get_function_named_in_call (t); | |
2134 | if (fn && TREE_CODE (fn) == FUNCTION_DECL | |
2135 | && DECL_CXX_CONSTRUCTOR_P (fn)) | |
2136 | type = DECL_CONTEXT (fn); | |
2137 | } | |
2138 | return type; | |
2139 | } | |
2140 | ||
2141 | /* We're about to initialize element INDEX of an array or class from VALUE. | |
2142 | Set up NEW_CTX appropriately by adjusting .object to refer to the | |
2143 | subobject and creating a new CONSTRUCTOR if the element is itself | |
2144 | a class or array. */ | |
2145 | ||
2146 | static void | |
2147 | init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, | |
2148 | tree index, tree &value) | |
2149 | { | |
2150 | new_ctx = *ctx; | |
2151 | ||
2152 | if (index && TREE_CODE (index) != INTEGER_CST | |
2153 | && TREE_CODE (index) != FIELD_DECL) | |
2154 | /* This won't have an element in the new CONSTRUCTOR. */ | |
2155 | return; | |
2156 | ||
2157 | tree type = initialized_type (value); | |
2158 | if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) | |
2159 | /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ | |
2160 | return; | |
2161 | ||
2162 | /* The sub-aggregate initializer might contain a placeholder; | |
2163 | update object to refer to the subobject and ctor to refer to | |
2164 | the (newly created) sub-initializer. */ | |
2165 | if (ctx->object) | |
2166 | new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); | |
2167 | tree elt = build_constructor (type, NULL); | |
2168 | CONSTRUCTOR_NO_IMPLICIT_ZERO (elt) = true; | |
2169 | new_ctx.ctor = elt; | |
2170 | ||
2171 | if (TREE_CODE (value) == TARGET_EXPR) | |
2172 | /* Avoid creating another CONSTRUCTOR when we expand the TARGET_EXPR. */ | |
2173 | value = TARGET_EXPR_INITIAL (value); | |
2174 | } | |
2175 | ||
2176 | /* We're about to process an initializer for a class or array TYPE. Make | |
2177 | sure that CTX is set up appropriately. */ | |
2178 | ||
2179 | static void | |
2180 | verify_ctor_sanity (const constexpr_ctx *ctx, tree type) | |
2181 | { | |
2182 | /* We don't bother building a ctor for an empty base subobject. */ | |
2183 | if (is_empty_class (type)) | |
2184 | return; | |
2185 | ||
2186 | /* We're in the middle of an initializer that might involve placeholders; | |
2187 | our caller should have created a CONSTRUCTOR for us to put the | |
2188 | initializer into. We will either return that constructor or T. */ | |
2189 | gcc_assert (ctx->ctor); | |
2190 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2191 | (type, TREE_TYPE (ctx->ctor))); | |
2192 | gcc_assert (CONSTRUCTOR_NELTS (ctx->ctor) == 0); | |
2193 | if (ctx->object) | |
2194 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2195 | (type, TREE_TYPE (ctx->object))); | |
2196 | gcc_assert (!ctx->object || !DECL_P (ctx->object) | |
2197 | || *(ctx->values->get (ctx->object)) == ctx->ctor); | |
2198 | } | |
2199 | ||
09b42213 | 2200 | /* Subroutine of cxx_eval_constant_expression. |
2201 | The expression tree T denotes a C-style array or a C-style | |
2202 | aggregate. Reduce it to a constant expression. */ | |
2203 | ||
2204 | static tree | |
cf72f34d | 2205 | cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2206 | bool lval, |
09b42213 | 2207 | bool *non_constant_p, bool *overflow_p) |
2208 | { | |
2209 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
09b42213 | 2210 | bool changed = false; |
2211 | gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t)); | |
cf72f34d | 2212 | |
2213 | verify_ctor_sanity (ctx, TREE_TYPE (t)); | |
2214 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
2215 | vec_alloc (*p, vec_safe_length (v)); | |
2216 | ||
2217 | unsigned i; tree index, value; | |
2218 | FOR_EACH_CONSTRUCTOR_ELT (v, i, index, value) | |
09b42213 | 2219 | { |
cf72f34d | 2220 | constexpr_ctx new_ctx; |
2221 | init_subob_ctx (ctx, new_ctx, index, value); | |
2222 | if (new_ctx.ctor != ctx->ctor) | |
2223 | /* If we built a new CONSTRUCTOR, attach it now so that other | |
2224 | initializers can refer to it. */ | |
2225 | CONSTRUCTOR_APPEND_ELT (*p, index, new_ctx.ctor); | |
2226 | tree elt = cxx_eval_constant_expression (&new_ctx, value, | |
1227ba74 | 2227 | lval, |
b2a43197 | 2228 | non_constant_p, overflow_p); |
09b42213 | 2229 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 2230 | if (ctx->quiet && *non_constant_p) |
cf72f34d | 2231 | break; |
2232 | if (elt != value) | |
09b42213 | 2233 | changed = true; |
cf72f34d | 2234 | if (index && TREE_CODE (index) == COMPONENT_REF) |
09b42213 | 2235 | { |
2236 | /* This is an initialization of a vfield inside a base | |
2237 | subaggregate that we already initialized; push this | |
2238 | initialization into the previous initialization. */ | |
cf72f34d | 2239 | constructor_elt *inner = base_field_constructor_elt (*p, index); |
09b42213 | 2240 | inner->value = elt; |
cf72f34d | 2241 | changed = true; |
09b42213 | 2242 | } |
cf72f34d | 2243 | else if (index |
2244 | && (TREE_CODE (index) == NOP_EXPR | |
2245 | || TREE_CODE (index) == POINTER_PLUS_EXPR)) | |
09b42213 | 2246 | { |
2247 | /* This is an initializer for an empty base; now that we've | |
2248 | checked that it's constant, we can ignore it. */ | |
cf72f34d | 2249 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (index)))); |
2250 | changed = true; | |
2251 | } | |
2252 | else if (new_ctx.ctor != ctx->ctor) | |
2253 | { | |
2254 | /* We appended this element above; update the value. */ | |
2255 | gcc_assert ((*p)->last().index == index); | |
2256 | (*p)->last().value = elt; | |
09b42213 | 2257 | } |
2258 | else | |
cf72f34d | 2259 | CONSTRUCTOR_APPEND_ELT (*p, index, elt); |
09b42213 | 2260 | } |
2261 | if (*non_constant_p || !changed) | |
cf72f34d | 2262 | return t; |
2263 | t = ctx->ctor; | |
2264 | /* We're done building this CONSTRUCTOR, so now we can interpret an | |
2265 | element without an explicit initializer as value-initialized. */ | |
2266 | CONSTRUCTOR_NO_IMPLICIT_ZERO (t) = false; | |
76249021 | 2267 | if (VECTOR_TYPE_P (TREE_TYPE (t))) |
09b42213 | 2268 | t = fold (t); |
2269 | return t; | |
2270 | } | |
2271 | ||
2272 | /* Subroutine of cxx_eval_constant_expression. | |
2273 | The expression tree T is a VEC_INIT_EXPR which denotes the desired | |
2274 | initialization of a non-static data member of array type. Reduce it to a | |
2275 | CONSTRUCTOR. | |
2276 | ||
2277 | Note that apart from value-initialization (when VALUE_INIT is true), | |
2278 | this is only intended to support value-initialization and the | |
2279 | initializations done by defaulted constructors for classes with | |
2280 | non-static data members of array type. In this case, VEC_INIT_EXPR_INIT | |
2281 | will either be NULL_TREE for the default constructor, or a COMPONENT_REF | |
2282 | for the copy/move constructor. */ | |
2283 | ||
2284 | static tree | |
cf72f34d | 2285 | cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, |
1227ba74 | 2286 | bool value_init, bool lval, |
09b42213 | 2287 | bool *non_constant_p, bool *overflow_p) |
2288 | { | |
2289 | tree elttype = TREE_TYPE (atype); | |
3e520b97 | 2290 | unsigned HOST_WIDE_INT max = tree_to_uhwi (array_type_nelts_top (atype)); |
cf72f34d | 2291 | verify_ctor_sanity (ctx, atype); |
2292 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
2293 | vec_alloc (*p, max + 1); | |
09b42213 | 2294 | bool pre_init = false; |
3e520b97 | 2295 | unsigned HOST_WIDE_INT i; |
09b42213 | 2296 | |
2297 | /* For the default constructor, build up a call to the default | |
2298 | constructor of the element type. We only need to handle class types | |
2299 | here, as for a constructor to be constexpr, all members must be | |
2300 | initialized, which for a defaulted default constructor means they must | |
2301 | be of a class type with a constexpr default constructor. */ | |
2302 | if (TREE_CODE (elttype) == ARRAY_TYPE) | |
2303 | /* We only do this at the lowest level. */; | |
2304 | else if (value_init) | |
2305 | { | |
2306 | init = build_value_init (elttype, tf_warning_or_error); | |
09b42213 | 2307 | pre_init = true; |
2308 | } | |
2309 | else if (!init) | |
2310 | { | |
2311 | vec<tree, va_gc> *argvec = make_tree_vector (); | |
2312 | init = build_special_member_call (NULL_TREE, complete_ctor_identifier, | |
2313 | &argvec, elttype, LOOKUP_NORMAL, | |
2314 | tf_warning_or_error); | |
2315 | release_tree_vector (argvec); | |
9c96033c | 2316 | init = build_aggr_init_expr (TREE_TYPE (init), init); |
09b42213 | 2317 | pre_init = true; |
2318 | } | |
2319 | ||
3e520b97 | 2320 | for (i = 0; i < max; ++i) |
09b42213 | 2321 | { |
2322 | tree idx = build_int_cst (size_type_node, i); | |
2323 | tree eltinit; | |
cf72f34d | 2324 | constexpr_ctx new_ctx; |
2325 | init_subob_ctx (ctx, new_ctx, idx, pre_init ? init : elttype); | |
2326 | if (new_ctx.ctor != ctx->ctor) | |
2327 | CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor); | |
09b42213 | 2328 | if (TREE_CODE (elttype) == ARRAY_TYPE) |
2329 | { | |
2330 | /* A multidimensional array; recurse. */ | |
2331 | if (value_init || init == NULL_TREE) | |
2332 | eltinit = NULL_TREE; | |
2333 | else | |
2334 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2335 | tf_warning_or_error); | |
cf72f34d | 2336 | eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, value_init, |
1227ba74 | 2337 | lval, |
09b42213 | 2338 | non_constant_p, overflow_p); |
2339 | } | |
2340 | else if (pre_init) | |
2341 | { | |
2342 | /* Initializing an element using value or default initialization | |
2343 | we just pre-built above. */ | |
cf72f34d | 2344 | eltinit = (cxx_eval_constant_expression |
f83e6885 | 2345 | (&new_ctx, init, |
1227ba74 | 2346 | lval, non_constant_p, overflow_p)); |
09b42213 | 2347 | } |
2348 | else | |
2349 | { | |
2350 | /* Copying an element. */ | |
2351 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2352 | (atype, TREE_TYPE (init))); | |
2353 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2354 | tf_warning_or_error); | |
2355 | if (!real_lvalue_p (init)) | |
2356 | eltinit = move (eltinit); | |
2357 | eltinit = force_rvalue (eltinit, tf_warning_or_error); | |
cf72f34d | 2358 | eltinit = (cxx_eval_constant_expression |
1227ba74 | 2359 | (&new_ctx, eltinit, lval, |
b2a43197 | 2360 | non_constant_p, overflow_p)); |
09b42213 | 2361 | } |
f83e6885 | 2362 | if (*non_constant_p && !ctx->quiet) |
cf72f34d | 2363 | break; |
2364 | if (new_ctx.ctor != ctx->ctor) | |
2365 | { | |
2366 | /* We appended this element above; update the value. */ | |
2367 | gcc_assert ((*p)->last().index == idx); | |
2368 | (*p)->last().value = eltinit; | |
2369 | } | |
2370 | else | |
2371 | CONSTRUCTOR_APPEND_ELT (*p, idx, eltinit); | |
09b42213 | 2372 | } |
2373 | ||
2374 | if (!*non_constant_p) | |
2375 | { | |
cf72f34d | 2376 | init = ctx->ctor; |
2377 | CONSTRUCTOR_NO_IMPLICIT_ZERO (init) = false; | |
09b42213 | 2378 | } |
09b42213 | 2379 | return init; |
2380 | } | |
2381 | ||
2382 | static tree | |
cf72f34d | 2383 | cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2384 | bool lval, |
09b42213 | 2385 | bool *non_constant_p, bool *overflow_p) |
2386 | { | |
2387 | tree atype = TREE_TYPE (t); | |
2388 | tree init = VEC_INIT_EXPR_INIT (t); | |
cf72f34d | 2389 | tree r = cxx_eval_vec_init_1 (ctx, atype, init, |
09b42213 | 2390 | VEC_INIT_EXPR_VALUE_INIT (t), |
1227ba74 | 2391 | lval, non_constant_p, overflow_p); |
09b42213 | 2392 | if (*non_constant_p) |
2393 | return t; | |
2394 | else | |
2395 | return r; | |
2396 | } | |
2397 | ||
2398 | /* A less strict version of fold_indirect_ref_1, which requires cv-quals to | |
2399 | match. We want to be less strict for simple *& folding; if we have a | |
2400 | non-const temporary that we access through a const pointer, that should | |
2401 | work. We handle this here rather than change fold_indirect_ref_1 | |
2402 | because we're dealing with things like ADDR_EXPR of INTEGER_CST which | |
2403 | don't really make sense outside of constant expression evaluation. Also | |
2404 | we want to allow folding to COMPONENT_REF, which could cause trouble | |
2405 | with TBAA in fold_indirect_ref_1. | |
2406 | ||
2407 | Try to keep this function synced with fold_indirect_ref_1. */ | |
2408 | ||
2409 | static tree | |
2410 | cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) | |
2411 | { | |
2412 | tree sub, subtype; | |
2413 | ||
2414 | sub = op0; | |
2415 | STRIP_NOPS (sub); | |
2416 | subtype = TREE_TYPE (sub); | |
2417 | if (!POINTER_TYPE_P (subtype)) | |
2418 | return NULL_TREE; | |
2419 | ||
2420 | if (TREE_CODE (sub) == ADDR_EXPR) | |
2421 | { | |
2422 | tree op = TREE_OPERAND (sub, 0); | |
2423 | tree optype = TREE_TYPE (op); | |
2424 | ||
2425 | /* *&CONST_DECL -> to the value of the const decl. */ | |
2426 | if (TREE_CODE (op) == CONST_DECL) | |
2427 | return DECL_INITIAL (op); | |
2428 | /* *&p => p; make sure to handle *&"str"[cst] here. */ | |
c4118b0c | 2429 | if (same_type_ignoring_top_level_qualifiers_p (optype, type) |
2430 | /* Also handle the case where the desired type is an array of unknown | |
2431 | bounds because the variable has had its bounds deduced since the | |
2432 | ADDR_EXPR was created. */ | |
2433 | || (TREE_CODE (type) == ARRAY_TYPE | |
2434 | && TREE_CODE (optype) == ARRAY_TYPE | |
2435 | && TYPE_DOMAIN (type) == NULL_TREE | |
2436 | && same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (optype), | |
2437 | TREE_TYPE (type)))) | |
09b42213 | 2438 | { |
2439 | tree fop = fold_read_from_constant_string (op); | |
2440 | if (fop) | |
2441 | return fop; | |
2442 | else | |
2443 | return op; | |
2444 | } | |
2445 | /* *(foo *)&fooarray => fooarray[0] */ | |
2446 | else if (TREE_CODE (optype) == ARRAY_TYPE | |
2447 | && (same_type_ignoring_top_level_qualifiers_p | |
2448 | (type, TREE_TYPE (optype)))) | |
2449 | { | |
2450 | tree type_domain = TYPE_DOMAIN (optype); | |
2451 | tree min_val = size_zero_node; | |
2452 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
2453 | min_val = TYPE_MIN_VALUE (type_domain); | |
2454 | return build4_loc (loc, ARRAY_REF, type, op, min_val, | |
2455 | NULL_TREE, NULL_TREE); | |
2456 | } | |
2457 | /* *(foo *)&complexfoo => __real__ complexfoo */ | |
2458 | else if (TREE_CODE (optype) == COMPLEX_TYPE | |
2459 | && (same_type_ignoring_top_level_qualifiers_p | |
2460 | (type, TREE_TYPE (optype)))) | |
2461 | return fold_build1_loc (loc, REALPART_EXPR, type, op); | |
2462 | /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 2463 | else if (VECTOR_TYPE_P (optype) |
09b42213 | 2464 | && (same_type_ignoring_top_level_qualifiers_p |
2465 | (type, TREE_TYPE (optype)))) | |
2466 | { | |
2467 | tree part_width = TYPE_SIZE (type); | |
2468 | tree index = bitsize_int (0); | |
2469 | return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, index); | |
2470 | } | |
2471 | /* Also handle conversion to an empty base class, which | |
2472 | is represented with a NOP_EXPR. */ | |
2473 | else if (is_empty_class (type) | |
2474 | && CLASS_TYPE_P (optype) | |
2475 | && DERIVED_FROM_P (type, optype)) | |
2476 | { | |
2477 | *empty_base = true; | |
2478 | return op; | |
2479 | } | |
2480 | /* *(foo *)&struct_with_foo_field => COMPONENT_REF */ | |
2481 | else if (RECORD_OR_UNION_TYPE_P (optype)) | |
2482 | { | |
2483 | tree field = TYPE_FIELDS (optype); | |
2484 | for (; field; field = DECL_CHAIN (field)) | |
2485 | if (TREE_CODE (field) == FIELD_DECL | |
2486 | && integer_zerop (byte_position (field)) | |
2487 | && (same_type_ignoring_top_level_qualifiers_p | |
2488 | (TREE_TYPE (field), type))) | |
2489 | { | |
2490 | return fold_build3 (COMPONENT_REF, type, op, field, NULL_TREE); | |
2491 | break; | |
2492 | } | |
2493 | } | |
2494 | } | |
2495 | else if (TREE_CODE (sub) == POINTER_PLUS_EXPR | |
2496 | && TREE_CODE (TREE_OPERAND (sub, 1)) == INTEGER_CST) | |
2497 | { | |
2498 | tree op00 = TREE_OPERAND (sub, 0); | |
2499 | tree op01 = TREE_OPERAND (sub, 1); | |
2500 | ||
2501 | STRIP_NOPS (op00); | |
2502 | if (TREE_CODE (op00) == ADDR_EXPR) | |
2503 | { | |
2504 | tree op00type; | |
2505 | op00 = TREE_OPERAND (op00, 0); | |
2506 | op00type = TREE_TYPE (op00); | |
2507 | ||
2508 | /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 2509 | if (VECTOR_TYPE_P (op00type) |
09b42213 | 2510 | && (same_type_ignoring_top_level_qualifiers_p |
2511 | (type, TREE_TYPE (op00type)))) | |
2512 | { | |
2513 | HOST_WIDE_INT offset = tree_to_shwi (op01); | |
2514 | tree part_width = TYPE_SIZE (type); | |
2515 | unsigned HOST_WIDE_INT part_widthi = tree_to_shwi (part_width)/BITS_PER_UNIT; | |
2516 | unsigned HOST_WIDE_INT indexi = offset * BITS_PER_UNIT; | |
2517 | tree index = bitsize_int (indexi); | |
2518 | ||
2519 | if (offset / part_widthi < TYPE_VECTOR_SUBPARTS (op00type)) | |
2520 | return fold_build3_loc (loc, | |
2521 | BIT_FIELD_REF, type, op00, | |
2522 | part_width, index); | |
2523 | ||
2524 | } | |
2525 | /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ | |
2526 | else if (TREE_CODE (op00type) == COMPLEX_TYPE | |
2527 | && (same_type_ignoring_top_level_qualifiers_p | |
2528 | (type, TREE_TYPE (op00type)))) | |
2529 | { | |
2530 | tree size = TYPE_SIZE_UNIT (type); | |
2531 | if (tree_int_cst_equal (size, op01)) | |
2532 | return fold_build1_loc (loc, IMAGPART_EXPR, type, op00); | |
2533 | } | |
2534 | /* ((foo *)&fooarray)[1] => fooarray[1] */ | |
2535 | else if (TREE_CODE (op00type) == ARRAY_TYPE | |
2536 | && (same_type_ignoring_top_level_qualifiers_p | |
2537 | (type, TREE_TYPE (op00type)))) | |
2538 | { | |
2539 | tree type_domain = TYPE_DOMAIN (op00type); | |
2540 | tree min_val = size_zero_node; | |
2541 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
2542 | min_val = TYPE_MIN_VALUE (type_domain); | |
2543 | op01 = size_binop_loc (loc, EXACT_DIV_EXPR, op01, | |
2544 | TYPE_SIZE_UNIT (type)); | |
2545 | op01 = size_binop_loc (loc, PLUS_EXPR, op01, min_val); | |
2546 | return build4_loc (loc, ARRAY_REF, type, op00, op01, | |
2547 | NULL_TREE, NULL_TREE); | |
2548 | } | |
2549 | /* Also handle conversion to an empty base class, which | |
2550 | is represented with a NOP_EXPR. */ | |
2551 | else if (is_empty_class (type) | |
2552 | && CLASS_TYPE_P (op00type) | |
2553 | && DERIVED_FROM_P (type, op00type)) | |
2554 | { | |
2555 | *empty_base = true; | |
2556 | return op00; | |
2557 | } | |
2558 | /* ((foo *)&struct_with_foo_field)[1] => COMPONENT_REF */ | |
2559 | else if (RECORD_OR_UNION_TYPE_P (op00type)) | |
2560 | { | |
2561 | tree field = TYPE_FIELDS (op00type); | |
2562 | for (; field; field = DECL_CHAIN (field)) | |
2563 | if (TREE_CODE (field) == FIELD_DECL | |
2564 | && tree_int_cst_equal (byte_position (field), op01) | |
2565 | && (same_type_ignoring_top_level_qualifiers_p | |
2566 | (TREE_TYPE (field), type))) | |
2567 | { | |
2568 | return fold_build3 (COMPONENT_REF, type, op00, | |
01b280db | 2569 | field, NULL_TREE); |
09b42213 | 2570 | break; |
2571 | } | |
2572 | } | |
2573 | } | |
2574 | } | |
2575 | /* *(foo *)fooarrptr => (*fooarrptr)[0] */ | |
2576 | else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE | |
2577 | && (same_type_ignoring_top_level_qualifiers_p | |
2578 | (type, TREE_TYPE (TREE_TYPE (subtype))))) | |
2579 | { | |
2580 | tree type_domain; | |
2581 | tree min_val = size_zero_node; | |
2582 | tree newsub = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL); | |
2583 | if (newsub) | |
2584 | sub = newsub; | |
2585 | else | |
2586 | sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub); | |
2587 | type_domain = TYPE_DOMAIN (TREE_TYPE (sub)); | |
2588 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
2589 | min_val = TYPE_MIN_VALUE (type_domain); | |
2590 | return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE, | |
2591 | NULL_TREE); | |
2592 | } | |
2593 | ||
2594 | return NULL_TREE; | |
2595 | } | |
2596 | ||
2597 | static tree | |
cf72f34d | 2598 | cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2599 | bool lval, |
09b42213 | 2600 | bool *non_constant_p, bool *overflow_p) |
2601 | { | |
2602 | tree orig_op0 = TREE_OPERAND (t, 0); | |
09b42213 | 2603 | bool empty_base = false; |
09b42213 | 2604 | |
d2c63826 | 2605 | /* We can handle a MEM_REF like an INDIRECT_REF, if MEM_REF's second |
2606 | operand is an integer-zero. Otherwise reject the MEM_REF for now. */ | |
2607 | ||
2608 | if (TREE_CODE (t) == MEM_REF | |
2609 | && (!TREE_OPERAND (t, 1) || !integer_zerop (TREE_OPERAND (t, 1)))) | |
2610 | { | |
2611 | gcc_assert (ctx->quiet); | |
2612 | *non_constant_p = true; | |
2613 | return t; | |
2614 | } | |
2615 | ||
7e0f3388 | 2616 | /* First try to simplify it directly. */ |
2617 | tree r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), orig_op0, | |
2618 | &empty_base); | |
2619 | if (!r) | |
09b42213 | 2620 | { |
7e0f3388 | 2621 | /* If that didn't work, evaluate the operand first. */ |
2622 | tree op0 = cxx_eval_constant_expression (ctx, orig_op0, | |
2623 | /*lval*/false, non_constant_p, | |
2624 | overflow_p); | |
2625 | /* Don't VERIFY_CONSTANT here. */ | |
2626 | if (*non_constant_p) | |
2627 | return t; | |
2628 | ||
2629 | r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), op0, | |
2630 | &empty_base); | |
2631 | if (r == NULL_TREE) | |
09b42213 | 2632 | { |
2633 | /* We couldn't fold to a constant value. Make sure it's not | |
2634 | something we should have been able to fold. */ | |
7e0f3388 | 2635 | tree sub = op0; |
2636 | STRIP_NOPS (sub); | |
2637 | if (TREE_CODE (sub) == ADDR_EXPR) | |
2638 | { | |
2639 | gcc_assert (!same_type_ignoring_top_level_qualifiers_p | |
2640 | (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t))); | |
2641 | /* DR 1188 says we don't have to deal with this. */ | |
2642 | if (!ctx->quiet) | |
2643 | error ("accessing value of %qE through a %qT glvalue in a " | |
2644 | "constant expression", build_fold_indirect_ref (sub), | |
2645 | TREE_TYPE (t)); | |
2646 | *non_constant_p = true; | |
2647 | return t; | |
2648 | } | |
2649 | ||
2650 | if (lval && op0 != orig_op0) | |
2651 | return build1 (INDIRECT_REF, TREE_TYPE (t), op0); | |
2652 | if (!lval) | |
2653 | VERIFY_CONSTANT (t); | |
09b42213 | 2654 | return t; |
2655 | } | |
2656 | } | |
2657 | ||
7e0f3388 | 2658 | r = cxx_eval_constant_expression (ctx, r, |
2659 | lval, non_constant_p, overflow_p); | |
2660 | if (*non_constant_p) | |
2661 | return t; | |
2662 | ||
09b42213 | 2663 | /* If we're pulling out the value of an empty base, make sure |
2664 | that the whole object is constant and then return an empty | |
2665 | CONSTRUCTOR. */ | |
1227ba74 | 2666 | if (empty_base && !lval) |
09b42213 | 2667 | { |
2668 | VERIFY_CONSTANT (r); | |
2669 | r = build_constructor (TREE_TYPE (t), NULL); | |
2670 | TREE_CONSTANT (r) = true; | |
2671 | } | |
2672 | ||
09b42213 | 2673 | return r; |
2674 | } | |
2675 | ||
2676 | /* Complain about R, a VAR_DECL, not being usable in a constant expression. | |
2677 | Shared between potential_constant_expression and | |
2678 | cxx_eval_constant_expression. */ | |
2679 | ||
2680 | static void | |
2681 | non_const_var_error (tree r) | |
2682 | { | |
2683 | tree type = TREE_TYPE (r); | |
2684 | error ("the value of %qD is not usable in a constant " | |
2685 | "expression", r); | |
2686 | /* Avoid error cascade. */ | |
2687 | if (DECL_INITIAL (r) == error_mark_node) | |
2688 | return; | |
2689 | if (DECL_DECLARED_CONSTEXPR_P (r)) | |
2690 | inform (DECL_SOURCE_LOCATION (r), | |
2691 | "%qD used in its own initializer", r); | |
2692 | else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) | |
2693 | { | |
2694 | if (!CP_TYPE_CONST_P (type)) | |
2695 | inform (DECL_SOURCE_LOCATION (r), | |
2696 | "%q#D is not const", r); | |
2697 | else if (CP_TYPE_VOLATILE_P (type)) | |
2698 | inform (DECL_SOURCE_LOCATION (r), | |
2699 | "%q#D is volatile", r); | |
2700 | else if (!DECL_INITIAL (r) | |
2701 | || !TREE_CONSTANT (DECL_INITIAL (r))) | |
2702 | inform (DECL_SOURCE_LOCATION (r), | |
2703 | "%qD was not initialized with a constant " | |
2704 | "expression", r); | |
2705 | else | |
2706 | gcc_unreachable (); | |
2707 | } | |
2708 | else | |
2709 | { | |
2710 | if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r)) | |
2711 | inform (DECL_SOURCE_LOCATION (r), | |
2712 | "%qD was not declared %<constexpr%>", r); | |
2713 | else | |
2714 | inform (DECL_SOURCE_LOCATION (r), | |
2715 | "%qD does not have integral or enumeration type", | |
2716 | r); | |
2717 | } | |
2718 | } | |
2719 | ||
2720 | /* Subroutine of cxx_eval_constant_expression. | |
2721 | Like cxx_eval_unary_expression, except for trinary expressions. */ | |
2722 | ||
2723 | static tree | |
cf72f34d | 2724 | cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2725 | bool lval, |
09b42213 | 2726 | bool *non_constant_p, bool *overflow_p) |
2727 | { | |
2728 | int i; | |
2729 | tree args[3]; | |
2730 | tree val; | |
2731 | ||
2732 | for (i = 0; i < 3; i++) | |
2733 | { | |
cf72f34d | 2734 | args[i] = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, i), |
1227ba74 | 2735 | lval, |
b2a43197 | 2736 | non_constant_p, overflow_p); |
09b42213 | 2737 | VERIFY_CONSTANT (args[i]); |
2738 | } | |
2739 | ||
2740 | val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t), | |
2741 | args[0], args[1], args[2]); | |
2742 | if (val == NULL_TREE) | |
2743 | return t; | |
2744 | VERIFY_CONSTANT (val); | |
2745 | return val; | |
2746 | } | |
2747 | ||
2748 | bool | |
2749 | var_in_constexpr_fn (tree t) | |
2750 | { | |
2751 | tree ctx = DECL_CONTEXT (t); | |
2752 | return (cxx_dialect >= cxx14 && ctx && TREE_CODE (ctx) == FUNCTION_DECL | |
2753 | && DECL_DECLARED_CONSTEXPR_P (ctx)); | |
2754 | } | |
2755 | ||
9c96033c | 2756 | /* Evaluate an INIT_EXPR or MODIFY_EXPR. */ |
2757 | ||
2758 | static tree | |
2759 | cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 2760 | bool lval, |
9c96033c | 2761 | bool *non_constant_p, bool *overflow_p) |
2762 | { | |
2763 | constexpr_ctx new_ctx = *ctx; | |
2764 | ||
8a36d0ec | 2765 | tree init = TREE_OPERAND (t, 1); |
2766 | if (TREE_CLOBBER_P (init)) | |
2767 | /* Just ignore clobbers. */ | |
2768 | return void_node; | |
2769 | ||
9c96033c | 2770 | /* First we figure out where we're storing to. */ |
2771 | tree target = TREE_OPERAND (t, 0); | |
9db9fc38 | 2772 | tree type = TREE_TYPE (target); |
9c96033c | 2773 | target = cxx_eval_constant_expression (ctx, target, |
f83e6885 | 2774 | true, |
b2a43197 | 2775 | non_constant_p, overflow_p); |
9c96033c | 2776 | if (*non_constant_p) |
2777 | return t; | |
2778 | ||
9db9fc38 | 2779 | if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (target), type)) |
2780 | { | |
2781 | /* For initialization of an empty base, the original target will be | |
2782 | *(base*)this, which the above evaluation resolves to the object | |
2783 | argument, which has the derived type rather than the base type. In | |
2784 | this situation, just evaluate the initializer and return, since | |
2785 | there's no actual data to store. */ | |
2786 | gcc_assert (is_empty_class (type)); | |
2787 | return cxx_eval_constant_expression (ctx, init, false, | |
2788 | non_constant_p, overflow_p); | |
2789 | } | |
2790 | ||
9c96033c | 2791 | /* And then find the underlying variable. */ |
2792 | vec<tree,va_gc> *refs = make_tree_vector(); | |
2793 | tree object = NULL_TREE; | |
2794 | for (tree probe = target; object == NULL_TREE; ) | |
2795 | { | |
2796 | switch (TREE_CODE (probe)) | |
2797 | { | |
2798 | case BIT_FIELD_REF: | |
2799 | case COMPONENT_REF: | |
2800 | case ARRAY_REF: | |
2801 | vec_safe_push (refs, TREE_OPERAND (probe, 1)); | |
2802 | vec_safe_push (refs, TREE_TYPE (probe)); | |
2803 | probe = TREE_OPERAND (probe, 0); | |
2804 | break; | |
2805 | ||
2806 | default: | |
2807 | object = probe; | |
9c96033c | 2808 | } |
2809 | } | |
2810 | ||
2811 | /* And then find/build up our initializer for the path to the subobject | |
2812 | we're initializing. */ | |
6fe83e54 | 2813 | tree *valp; |
2814 | if (DECL_P (object)) | |
2815 | valp = ctx->values->get (object); | |
2816 | else | |
2817 | valp = NULL; | |
9c96033c | 2818 | if (!valp) |
2819 | { | |
2820 | /* A constant-expression cannot modify objects from outside the | |
2821 | constant-expression. */ | |
f83e6885 | 2822 | if (!ctx->quiet) |
6fe83e54 | 2823 | error ("modification of %qE is not a constant-expression", object); |
9c96033c | 2824 | *non_constant_p = true; |
2825 | return t; | |
2826 | } | |
9db9fc38 | 2827 | type = TREE_TYPE (object); |
a02b42fe | 2828 | bool no_zero_init = true; |
9c96033c | 2829 | while (!refs->is_empty()) |
2830 | { | |
2831 | if (*valp == NULL_TREE) | |
2832 | { | |
2833 | *valp = build_constructor (type, NULL); | |
a02b42fe | 2834 | CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp) = no_zero_init; |
9c96033c | 2835 | } |
a02b42fe | 2836 | /* If the value of object is already zero-initialized, any new ctors for |
2837 | subobjects will also be zero-initialized. */ | |
2838 | no_zero_init = CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp); | |
9c96033c | 2839 | |
7963b19d | 2840 | enum tree_code code = TREE_CODE (type); |
9c96033c | 2841 | type = refs->pop(); |
7963b19d | 2842 | tree index = refs->pop(); |
9c96033c | 2843 | |
9c96033c | 2844 | constructor_elt *cep = NULL; |
7963b19d | 2845 | if (code == ARRAY_TYPE) |
2846 | { | |
2847 | HOST_WIDE_INT i | |
2848 | = find_array_ctor_elt (*valp, index, /*insert*/true); | |
2849 | gcc_assert (i >= 0); | |
2850 | cep = CONSTRUCTOR_ELT (*valp, i); | |
2851 | gcc_assert (TREE_CODE (cep->index) != RANGE_EXPR); | |
2852 | } | |
2853 | else | |
2854 | { | |
2855 | gcc_assert (TREE_CODE (index) == FIELD_DECL); | |
2856 | for (unsigned HOST_WIDE_INT idx = 0; | |
2857 | vec_safe_iterate (CONSTRUCTOR_ELTS (*valp), idx, &cep); | |
2858 | idx++) | |
2859 | if (index == cep->index) | |
2860 | break; | |
2861 | if (!cep) | |
2862 | { | |
2863 | constructor_elt ce = { index, NULL_TREE }; | |
2864 | cep = vec_safe_push (CONSTRUCTOR_ELTS (*valp), ce); | |
2865 | } | |
2866 | } | |
9c96033c | 2867 | valp = &cep->value; |
2868 | } | |
2869 | release_tree_vector (refs); | |
2870 | ||
469dc5a6 | 2871 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) |
9c96033c | 2872 | { |
2873 | /* Create a new CONSTRUCTOR in case evaluation of the initializer | |
2874 | wants to modify it. */ | |
469dc5a6 | 2875 | if (*valp == NULL_TREE) |
6cded085 | 2876 | { |
2877 | *valp = new_ctx.ctor = build_constructor (type, NULL); | |
2878 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = no_zero_init; | |
2879 | } | |
2880 | else | |
2881 | new_ctx.ctor = *valp; | |
9c96033c | 2882 | new_ctx.object = target; |
2883 | } | |
2884 | ||
8a36d0ec | 2885 | init = cxx_eval_constant_expression (&new_ctx, init, false, |
2886 | non_constant_p, overflow_p); | |
9c96033c | 2887 | if (target == object) |
469dc5a6 | 2888 | { |
2889 | /* The hash table might have moved since the get earlier. */ | |
2890 | valp = ctx->values->get (object); | |
2891 | if (TREE_CODE (init) == CONSTRUCTOR) | |
2892 | /* An outer ctx->ctor might be pointing to *valp, so just replace | |
2893 | its contents. */ | |
2894 | CONSTRUCTOR_ELTS (*valp) = CONSTRUCTOR_ELTS (init); | |
2895 | else | |
2896 | *valp = init; | |
2897 | } | |
9c96033c | 2898 | else |
2899 | *valp = init; | |
2900 | ||
2901 | if (*non_constant_p) | |
2902 | return t; | |
1227ba74 | 2903 | else if (lval) |
9c96033c | 2904 | return target; |
2905 | else | |
dfac7dd2 | 2906 | return init; |
9c96033c | 2907 | } |
2908 | ||
2909 | /* Evaluate a ++ or -- expression. */ | |
2910 | ||
2911 | static tree | |
2912 | cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 2913 | bool lval, |
9c96033c | 2914 | bool *non_constant_p, bool *overflow_p) |
2915 | { | |
2916 | enum tree_code code = TREE_CODE (t); | |
2917 | tree type = TREE_TYPE (t); | |
2918 | tree op = TREE_OPERAND (t, 0); | |
2919 | tree offset = TREE_OPERAND (t, 1); | |
2920 | gcc_assert (TREE_CONSTANT (offset)); | |
2921 | ||
2922 | /* The operand as an lvalue. */ | |
f83e6885 | 2923 | op = cxx_eval_constant_expression (ctx, op, true, |
b2a43197 | 2924 | non_constant_p, overflow_p); |
9c96033c | 2925 | |
2926 | /* The operand as an rvalue. */ | |
2927 | tree val = rvalue (op); | |
f83e6885 | 2928 | val = cxx_eval_constant_expression (ctx, val, false, |
b2a43197 | 2929 | non_constant_p, overflow_p); |
35f2c28f | 2930 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
2931 | a local array in a constexpr function. */ | |
2932 | bool ptr = POINTER_TYPE_P (TREE_TYPE (val)); | |
2933 | if (!ptr) | |
2934 | VERIFY_CONSTANT (val); | |
9c96033c | 2935 | |
2936 | /* The modified value. */ | |
2937 | bool inc = (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR); | |
c8a8f7ad | 2938 | tree mod; |
2939 | if (POINTER_TYPE_P (type)) | |
2940 | { | |
2941 | /* The middle end requires pointers to use POINTER_PLUS_EXPR. */ | |
2942 | offset = convert_to_ptrofftype (offset); | |
2943 | if (!inc) | |
2944 | offset = fold_build1 (NEGATE_EXPR, TREE_TYPE (offset), offset); | |
2945 | mod = fold_build2 (POINTER_PLUS_EXPR, type, val, offset); | |
2946 | } | |
2947 | else | |
2948 | mod = fold_build2 (inc ? PLUS_EXPR : MINUS_EXPR, type, val, offset); | |
35f2c28f | 2949 | if (!ptr) |
2950 | VERIFY_CONSTANT (mod); | |
9c96033c | 2951 | |
2952 | /* Storing the modified value. */ | |
2953 | tree store = build2 (MODIFY_EXPR, type, op, mod); | |
f83e6885 | 2954 | cxx_eval_constant_expression (ctx, store, |
b2a43197 | 2955 | true, non_constant_p, overflow_p); |
9c96033c | 2956 | |
2957 | /* And the value of the expression. */ | |
2958 | if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) | |
2959 | { | |
2960 | /* Prefix ops are lvalues. */ | |
1227ba74 | 2961 | if (lval) |
9c96033c | 2962 | return op; |
2963 | else | |
2964 | /* But we optimize when the caller wants an rvalue. */ | |
2965 | return mod; | |
2966 | } | |
2967 | else | |
2968 | /* Postfix ops are rvalues. */ | |
2969 | return val; | |
2970 | } | |
2971 | ||
00f21715 | 2972 | /* Predicates for the meaning of *jump_target. */ |
2973 | ||
2974 | static bool | |
2975 | returns (tree *jump_target) | |
2976 | { | |
2977 | return *jump_target | |
2978 | && TREE_CODE (*jump_target) == RETURN_EXPR; | |
2979 | } | |
2980 | ||
2981 | static bool | |
2982 | breaks (tree *jump_target) | |
2983 | { | |
2984 | return *jump_target | |
2985 | && TREE_CODE (*jump_target) == LABEL_DECL | |
2986 | && LABEL_DECL_BREAK (*jump_target); | |
2987 | } | |
2988 | ||
2989 | static bool | |
2990 | continues (tree *jump_target) | |
2991 | { | |
2992 | return *jump_target | |
2993 | && TREE_CODE (*jump_target) == LABEL_DECL | |
2994 | && LABEL_DECL_CONTINUE (*jump_target); | |
2995 | } | |
2996 | ||
2997 | static bool | |
2998 | switches (tree *jump_target) | |
2999 | { | |
3000 | return *jump_target | |
3001 | && TREE_CODE (*jump_target) == INTEGER_CST; | |
3002 | } | |
3003 | ||
3004 | /* Subroutine of cxx_eval_statement_list. Determine whether the statement | |
3005 | at I matches *jump_target. If we're looking for a case label and we see | |
3006 | the default label, copy I into DEFAULT_LABEL. */ | |
3007 | ||
3008 | static bool | |
3009 | label_matches (tree *jump_target, tree_stmt_iterator i, | |
3010 | tree_stmt_iterator& default_label) | |
3011 | { | |
3012 | tree stmt = tsi_stmt (i); | |
3013 | switch (TREE_CODE (*jump_target)) | |
3014 | { | |
3015 | case LABEL_DECL: | |
3016 | if (TREE_CODE (stmt) == LABEL_EXPR | |
3017 | && LABEL_EXPR_LABEL (stmt) == *jump_target) | |
3018 | return true; | |
3019 | break; | |
3020 | ||
3021 | case INTEGER_CST: | |
3022 | if (TREE_CODE (stmt) == CASE_LABEL_EXPR) | |
3023 | { | |
3024 | if (!CASE_LOW (stmt)) | |
3025 | default_label = i; | |
3026 | else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt))) | |
3027 | return true; | |
3028 | } | |
3029 | break; | |
3030 | ||
3031 | default: | |
3032 | gcc_unreachable (); | |
3033 | } | |
3034 | return false; | |
3035 | } | |
3036 | ||
3037 | /* Evaluate a STATEMENT_LIST for side-effects. Handles various jump | |
3038 | semantics, for switch, break, continue, and return. */ | |
3039 | ||
3040 | static tree | |
3041 | cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3042 | bool *non_constant_p, bool *overflow_p, |
3043 | tree *jump_target) | |
3044 | { | |
3045 | tree_stmt_iterator i; | |
3046 | tree_stmt_iterator default_label = tree_stmt_iterator(); | |
da7981e0 | 3047 | tree local_target; |
3048 | /* In a statement-expression we want to return the last value. */ | |
3049 | tree r = NULL_TREE; | |
3050 | if (!jump_target) | |
3051 | { | |
3052 | local_target = NULL_TREE; | |
3053 | jump_target = &local_target; | |
3054 | } | |
00f21715 | 3055 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) |
3056 | { | |
3057 | reenter: | |
3058 | tree stmt = tsi_stmt (i); | |
3059 | if (*jump_target) | |
3060 | { | |
3061 | if (TREE_CODE (stmt) == STATEMENT_LIST) | |
3062 | /* The label we want might be inside. */; | |
3063 | else if (label_matches (jump_target, i, default_label)) | |
3064 | /* Found it. */ | |
3065 | *jump_target = NULL_TREE; | |
3066 | else | |
3067 | continue; | |
3068 | } | |
da7981e0 | 3069 | r = cxx_eval_constant_expression (ctx, stmt, false, |
3070 | non_constant_p, overflow_p, | |
3071 | jump_target); | |
00f21715 | 3072 | if (*non_constant_p) |
3073 | break; | |
3074 | if (returns (jump_target) || breaks (jump_target)) | |
3075 | break; | |
3076 | } | |
3077 | if (switches (jump_target) && !tsi_end_p (default_label)) | |
3078 | { | |
3079 | i = default_label; | |
3080 | *jump_target = NULL_TREE; | |
3081 | goto reenter; | |
3082 | } | |
da7981e0 | 3083 | return r; |
00f21715 | 3084 | } |
3085 | ||
3086 | /* Evaluate a LOOP_EXPR for side-effects. Handles break and return | |
3087 | semantics; continue semantics are covered by cxx_eval_statement_list. */ | |
3088 | ||
3089 | static tree | |
3090 | cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3091 | bool *non_constant_p, bool *overflow_p, |
3092 | tree *jump_target) | |
3093 | { | |
3094 | tree body = TREE_OPERAND (t, 0); | |
3095 | while (true) | |
3096 | { | |
f83e6885 | 3097 | cxx_eval_statement_list (ctx, body, |
00f21715 | 3098 | non_constant_p, overflow_p, jump_target); |
b0295f63 | 3099 | if (returns (jump_target) || breaks (jump_target) || *non_constant_p) |
00f21715 | 3100 | break; |
3101 | } | |
3102 | if (breaks (jump_target)) | |
3103 | *jump_target = NULL_TREE; | |
3104 | return NULL_TREE; | |
3105 | } | |
3106 | ||
3107 | /* Evaluate a SWITCH_EXPR for side-effects. Handles switch and break jump | |
3108 | semantics. */ | |
3109 | ||
3110 | static tree | |
3111 | cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3112 | bool *non_constant_p, bool *overflow_p, |
3113 | tree *jump_target) | |
3114 | { | |
3115 | tree cond = TREE_OPERAND (t, 0); | |
f83e6885 | 3116 | cond = cxx_eval_constant_expression (ctx, cond, false, |
b2a43197 | 3117 | non_constant_p, overflow_p); |
00f21715 | 3118 | VERIFY_CONSTANT (cond); |
3119 | *jump_target = cond; | |
3120 | ||
3121 | tree body = TREE_OPERAND (t, 1); | |
f83e6885 | 3122 | cxx_eval_statement_list (ctx, body, |
00f21715 | 3123 | non_constant_p, overflow_p, jump_target); |
3124 | if (breaks (jump_target) || switches (jump_target)) | |
3125 | *jump_target = NULL_TREE; | |
3126 | return NULL_TREE; | |
3127 | } | |
3128 | ||
35b68da8 | 3129 | /* Subroutine of cxx_eval_constant_expression. |
3130 | Attempt to reduce a POINTER_PLUS_EXPR expression T. */ | |
3131 | ||
3132 | static tree | |
3133 | cxx_eval_pointer_plus_expression (const constexpr_ctx *ctx, tree t, | |
3134 | bool lval, bool *non_constant_p, | |
3135 | bool *overflow_p) | |
3136 | { | |
51a019c5 | 3137 | tree orig_type = TREE_TYPE (t); |
35b68da8 | 3138 | tree op00 = TREE_OPERAND (t, 0); |
3139 | tree op01 = TREE_OPERAND (t, 1); | |
3140 | location_t loc = EXPR_LOCATION (t); | |
3141 | ||
f070a770 | 3142 | op00 = cxx_eval_constant_expression (ctx, op00, lval, |
3143 | non_constant_p, overflow_p); | |
3144 | ||
35b68da8 | 3145 | STRIP_NOPS (op00); |
3146 | if (TREE_CODE (op00) != ADDR_EXPR) | |
3147 | return NULL_TREE; | |
3148 | ||
d2c63826 | 3149 | op01 = cxx_eval_constant_expression (ctx, op01, lval, |
3150 | non_constant_p, overflow_p); | |
35b68da8 | 3151 | op00 = TREE_OPERAND (op00, 0); |
3152 | ||
3153 | /* &A[i] p+ j => &A[i + j] */ | |
3154 | if (TREE_CODE (op00) == ARRAY_REF | |
3155 | && TREE_CODE (TREE_OPERAND (op00, 1)) == INTEGER_CST | |
51a019c5 | 3156 | && TREE_CODE (op01) == INTEGER_CST |
3157 | && TYPE_SIZE_UNIT (TREE_TYPE (op00)) | |
3158 | && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (op00))) == INTEGER_CST) | |
35b68da8 | 3159 | { |
3160 | tree type = TREE_TYPE (op00); | |
3161 | t = fold_convert_loc (loc, ssizetype, TREE_OPERAND (op00, 1)); | |
3162 | tree nelts = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (op00, 0))); | |
3163 | /* Don't fold an out-of-bound access. */ | |
3164 | if (!tree_int_cst_le (t, nelts)) | |
3165 | return NULL_TREE; | |
51a019c5 | 3166 | op01 = cp_fold_convert (ssizetype, op01); |
3167 | /* Don't fold if op01 can't be divided exactly by TYPE_SIZE_UNIT. | |
3168 | constexpr int A[1]; ... (char *)&A[0] + 1 */ | |
3169 | if (!integer_zerop (fold_build2_loc (loc, TRUNC_MOD_EXPR, sizetype, | |
3170 | op01, TYPE_SIZE_UNIT (type)))) | |
3171 | return NULL_TREE; | |
35b68da8 | 3172 | /* Make sure to treat the second operand of POINTER_PLUS_EXPR |
3173 | as signed. */ | |
51a019c5 | 3174 | op01 = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, op01, |
35b68da8 | 3175 | TYPE_SIZE_UNIT (type)); |
3176 | t = size_binop_loc (loc, PLUS_EXPR, op01, t); | |
3177 | t = build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (op00, 0), | |
3178 | t, NULL_TREE, NULL_TREE); | |
3179 | t = cp_build_addr_expr (t, tf_warning_or_error); | |
51a019c5 | 3180 | t = cp_fold_convert (orig_type, t); |
35b68da8 | 3181 | return cxx_eval_constant_expression (ctx, t, lval, non_constant_p, |
3182 | overflow_p); | |
3183 | } | |
3184 | ||
3185 | return NULL_TREE; | |
3186 | } | |
3187 | ||
09b42213 | 3188 | /* Attempt to reduce the expression T to a constant value. |
3189 | On failure, issue diagnostic and return error_mark_node. */ | |
3190 | /* FIXME unify with c_fully_fold */ | |
9c96033c | 3191 | /* FIXME overflow_p is too global */ |
09b42213 | 3192 | |
3193 | static tree | |
cf72f34d | 3194 | cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3195 | bool lval, |
00f21715 | 3196 | bool *non_constant_p, bool *overflow_p, |
3197 | tree *jump_target) | |
09b42213 | 3198 | { |
cf72f34d | 3199 | constexpr_ctx new_ctx; |
09b42213 | 3200 | tree r = t; |
3201 | ||
3202 | if (t == error_mark_node) | |
3203 | { | |
3204 | *non_constant_p = true; | |
3205 | return t; | |
3206 | } | |
3207 | if (CONSTANT_CLASS_P (t)) | |
3208 | { | |
f16ed232 | 3209 | if (TREE_OVERFLOW (t) && (!flag_permissive || ctx->quiet)) |
09b42213 | 3210 | *overflow_p = true; |
3211 | return t; | |
3212 | } | |
09b42213 | 3213 | |
3214 | switch (TREE_CODE (t)) | |
3215 | { | |
9c96033c | 3216 | case RESULT_DECL: |
1227ba74 | 3217 | if (lval) |
9c96033c | 3218 | return t; |
3219 | /* We ask for an rvalue for the RESULT_DECL when indirecting | |
92a9c89e | 3220 | through an invisible reference, or in named return value |
3221 | optimization. */ | |
9c96033c | 3222 | return (*ctx->values->get (t)); |
3223 | ||
09b42213 | 3224 | case VAR_DECL: |
8b2b2f24 | 3225 | case CONST_DECL: |
3226 | /* We used to not check lval for CONST_DECL, but darwin.c uses | |
3227 | CONST_DECL for aggregate constants. */ | |
1227ba74 | 3228 | if (lval) |
09b42213 | 3229 | return t; |
2055d27a | 3230 | if (ctx->strict) |
3231 | r = decl_really_constant_value (t); | |
3232 | else | |
3233 | r = decl_constant_value (t); | |
09b42213 | 3234 | if (TREE_CODE (r) == TARGET_EXPR |
3235 | && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR) | |
3236 | r = TARGET_EXPR_INITIAL (r); | |
f4ae4202 | 3237 | if (VAR_P (r)) |
cf72f34d | 3238 | if (tree *p = ctx->values->get (r)) |
a143e277 | 3239 | if (*p != NULL_TREE) |
3240 | r = *p; | |
09b42213 | 3241 | if (DECL_P (r)) |
3242 | { | |
f83e6885 | 3243 | if (!ctx->quiet) |
09b42213 | 3244 | non_const_var_error (r); |
3245 | *non_constant_p = true; | |
3246 | } | |
3247 | break; | |
3248 | ||
3249 | case FUNCTION_DECL: | |
3250 | case TEMPLATE_DECL: | |
3251 | case LABEL_DECL: | |
00f21715 | 3252 | case LABEL_EXPR: |
3253 | case CASE_LABEL_EXPR: | |
09b42213 | 3254 | return t; |
3255 | ||
3256 | case PARM_DECL: | |
88a59139 | 3257 | if (lval && TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE) |
9c96033c | 3258 | /* glvalue use. */; |
3259 | else if (tree *p = ctx->values->get (r)) | |
3260 | r = *p; | |
1227ba74 | 3261 | else if (lval) |
09b42213 | 3262 | /* Defer in case this is only used for its type. */; |
1eb418cc | 3263 | else if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE) |
3264 | /* Defer, there's no lvalue->rvalue conversion. */; | |
a6613de7 | 3265 | else if (is_empty_class (TREE_TYPE (t))) |
3266 | { | |
3267 | /* If the class is empty, we aren't actually loading anything. */ | |
3268 | r = build_constructor (TREE_TYPE (t), NULL); | |
3269 | TREE_CONSTANT (r) = true; | |
3270 | } | |
09b42213 | 3271 | else |
3272 | { | |
f83e6885 | 3273 | if (!ctx->quiet) |
09b42213 | 3274 | error ("%qE is not a constant expression", t); |
3275 | *non_constant_p = true; | |
3276 | } | |
3277 | break; | |
3278 | ||
3279 | case CALL_EXPR: | |
3280 | case AGGR_INIT_EXPR: | |
1227ba74 | 3281 | r = cxx_eval_call_expression (ctx, t, lval, |
09b42213 | 3282 | non_constant_p, overflow_p); |
3283 | break; | |
3284 | ||
9c96033c | 3285 | case DECL_EXPR: |
3286 | { | |
3287 | r = DECL_EXPR_DECL (t); | |
3288 | if (AGGREGATE_TYPE_P (TREE_TYPE (r)) | |
3289 | || VECTOR_TYPE_P (TREE_TYPE (r))) | |
3290 | { | |
3291 | new_ctx = *ctx; | |
3292 | new_ctx.object = r; | |
3293 | new_ctx.ctor = build_constructor (TREE_TYPE (r), NULL); | |
3294 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
3295 | new_ctx.values->put (r, new_ctx.ctor); | |
3296 | ctx = &new_ctx; | |
3297 | } | |
3298 | ||
3299 | if (tree init = DECL_INITIAL (r)) | |
3300 | { | |
3301 | init = cxx_eval_constant_expression (ctx, init, | |
f83e6885 | 3302 | false, |
b2a43197 | 3303 | non_constant_p, overflow_p); |
9c96033c | 3304 | ctx->values->put (r, init); |
3305 | } | |
3306 | else if (ctx == &new_ctx) | |
3307 | /* We gave it a CONSTRUCTOR above. */; | |
3308 | else | |
3309 | ctx->values->put (r, NULL_TREE); | |
3310 | } | |
3311 | break; | |
3312 | ||
09b42213 | 3313 | case TARGET_EXPR: |
3314 | if (!literal_type_p (TREE_TYPE (t))) | |
3315 | { | |
f83e6885 | 3316 | if (!ctx->quiet) |
09b42213 | 3317 | { |
3318 | error ("temporary of non-literal type %qT in a " | |
3319 | "constant expression", TREE_TYPE (t)); | |
3320 | explain_non_literal_class (TREE_TYPE (t)); | |
3321 | } | |
3322 | *non_constant_p = true; | |
3323 | break; | |
3324 | } | |
cf72f34d | 3325 | if ((AGGREGATE_TYPE_P (TREE_TYPE (t)) || VECTOR_TYPE_P (TREE_TYPE (t)))) |
3326 | { | |
3327 | /* We're being expanded without an explicit target, so start | |
3328 | initializing a new object; expansion with an explicit target | |
3329 | strips the TARGET_EXPR before we get here. */ | |
3330 | new_ctx = *ctx; | |
3331 | new_ctx.ctor = build_constructor (TREE_TYPE (t), NULL); | |
3332 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
3333 | new_ctx.object = TARGET_EXPR_SLOT (t); | |
3334 | ctx->values->put (new_ctx.object, new_ctx.ctor); | |
3335 | ctx = &new_ctx; | |
3336 | } | |
1227ba74 | 3337 | /* Pass false for 'lval' because this indicates |
09b42213 | 3338 | initialization of a temporary. */ |
cf72f34d | 3339 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 3340 | false, |
b2a43197 | 3341 | non_constant_p, overflow_p); |
09b42213 | 3342 | if (!*non_constant_p) |
3343 | /* Adjust the type of the result to the type of the temporary. */ | |
3344 | r = adjust_temp_type (TREE_TYPE (t), r); | |
1227ba74 | 3345 | if (lval) |
1eb418cc | 3346 | { |
3347 | tree slot = TARGET_EXPR_SLOT (t); | |
3348 | ctx->values->put (slot, r); | |
3349 | return slot; | |
3350 | } | |
09b42213 | 3351 | break; |
3352 | ||
9c96033c | 3353 | case INIT_EXPR: |
9c96033c | 3354 | case MODIFY_EXPR: |
1227ba74 | 3355 | r = cxx_eval_store_expression (ctx, t, lval, |
9c96033c | 3356 | non_constant_p, overflow_p); |
3357 | break; | |
3358 | ||
09b42213 | 3359 | case SCOPE_REF: |
cf72f34d | 3360 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 3361 | lval, |
b2a43197 | 3362 | non_constant_p, overflow_p); |
09b42213 | 3363 | break; |
3364 | ||
3365 | case RETURN_EXPR: | |
10fb495c | 3366 | if (TREE_OPERAND (t, 0) != NULL_TREE) |
3367 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
3368 | lval, | |
3369 | non_constant_p, overflow_p); | |
00f21715 | 3370 | *jump_target = t; |
3371 | break; | |
3372 | ||
e0e672a0 | 3373 | case SAVE_EXPR: |
3374 | /* Avoid evaluating a SAVE_EXPR more than once. */ | |
3375 | if (tree *p = ctx->values->get (t)) | |
3376 | r = *p; | |
3377 | else | |
3378 | { | |
c8f6aeb1 | 3379 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), false, |
e0e672a0 | 3380 | non_constant_p, overflow_p); |
3381 | ctx->values->put (t, r); | |
3382 | } | |
3383 | break; | |
3384 | ||
09b42213 | 3385 | case NON_LVALUE_EXPR: |
3386 | case TRY_CATCH_EXPR: | |
7f67d68c | 3387 | case TRY_BLOCK: |
09b42213 | 3388 | case CLEANUP_POINT_EXPR: |
3389 | case MUST_NOT_THROW_EXPR: | |
9c96033c | 3390 | case EXPR_STMT: |
3391 | case EH_SPEC_BLOCK: | |
cf72f34d | 3392 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 3393 | lval, |
00f21715 | 3394 | non_constant_p, overflow_p, |
3395 | jump_target); | |
09b42213 | 3396 | break; |
3397 | ||
7f67d68c | 3398 | case TRY_FINALLY_EXPR: |
3399 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
3400 | non_constant_p, overflow_p, | |
3401 | jump_target); | |
3402 | if (!*non_constant_p) | |
3403 | /* Also evaluate the cleanup. */ | |
3404 | cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), true, | |
3405 | non_constant_p, overflow_p, | |
3406 | jump_target); | |
3407 | break; | |
3408 | ||
09b42213 | 3409 | /* These differ from cxx_eval_unary_expression in that this doesn't |
3410 | check for a constant operand or result; an address can be | |
3411 | constant without its operand being, and vice versa. */ | |
d2c63826 | 3412 | case MEM_REF: |
09b42213 | 3413 | case INDIRECT_REF: |
1227ba74 | 3414 | r = cxx_eval_indirect_ref (ctx, t, lval, |
09b42213 | 3415 | non_constant_p, overflow_p); |
3416 | break; | |
3417 | ||
3418 | case ADDR_EXPR: | |
3419 | { | |
3420 | tree oldop = TREE_OPERAND (t, 0); | |
cf72f34d | 3421 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 3422 | /*lval*/true, |
b2a43197 | 3423 | non_constant_p, overflow_p); |
09b42213 | 3424 | /* Don't VERIFY_CONSTANT here. */ |
3425 | if (*non_constant_p) | |
3426 | return t; | |
1eb418cc | 3427 | gcc_checking_assert (TREE_CODE (op) != CONSTRUCTOR); |
09b42213 | 3428 | /* This function does more aggressive folding than fold itself. */ |
3429 | r = build_fold_addr_expr_with_type (op, TREE_TYPE (t)); | |
3430 | if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop) | |
3431 | return t; | |
3432 | break; | |
3433 | } | |
3434 | ||
3435 | case REALPART_EXPR: | |
3436 | case IMAGPART_EXPR: | |
3437 | case CONJ_EXPR: | |
3438 | case FIX_TRUNC_EXPR: | |
3439 | case FLOAT_EXPR: | |
3440 | case NEGATE_EXPR: | |
3441 | case ABS_EXPR: | |
3442 | case BIT_NOT_EXPR: | |
3443 | case TRUTH_NOT_EXPR: | |
3444 | case FIXED_CONVERT_EXPR: | |
1227ba74 | 3445 | r = cxx_eval_unary_expression (ctx, t, lval, |
09b42213 | 3446 | non_constant_p, overflow_p); |
3447 | break; | |
3448 | ||
3449 | case SIZEOF_EXPR: | |
d2c63826 | 3450 | r = fold_sizeof_expr (t); |
09b42213 | 3451 | VERIFY_CONSTANT (r); |
3452 | break; | |
3453 | ||
3454 | case COMPOUND_EXPR: | |
3455 | { | |
3456 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
3457 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
3458 | introduced by build_call_a. */ | |
3459 | tree op0 = TREE_OPERAND (t, 0); | |
3460 | tree op1 = TREE_OPERAND (t, 1); | |
3461 | STRIP_NOPS (op1); | |
3462 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
3463 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
f83e6885 | 3464 | r = cxx_eval_constant_expression (ctx, op0, |
1227ba74 | 3465 | lval, non_constant_p, overflow_p, |
00f21715 | 3466 | jump_target); |
09b42213 | 3467 | else |
3468 | { | |
3469 | /* Check that the LHS is constant and then discard it. */ | |
f83e6885 | 3470 | cxx_eval_constant_expression (ctx, op0, |
c8f6aeb1 | 3471 | true, non_constant_p, overflow_p, |
00f21715 | 3472 | jump_target); |
09b42213 | 3473 | op1 = TREE_OPERAND (t, 1); |
f83e6885 | 3474 | r = cxx_eval_constant_expression (ctx, op1, |
1227ba74 | 3475 | lval, non_constant_p, overflow_p, |
00f21715 | 3476 | jump_target); |
09b42213 | 3477 | } |
3478 | } | |
3479 | break; | |
3480 | ||
3481 | case POINTER_PLUS_EXPR: | |
35b68da8 | 3482 | r = cxx_eval_pointer_plus_expression (ctx, t, lval, non_constant_p, |
3483 | overflow_p); | |
3484 | if (r) | |
3485 | break; | |
3486 | /* else fall through */ | |
3487 | ||
09b42213 | 3488 | case PLUS_EXPR: |
3489 | case MINUS_EXPR: | |
3490 | case MULT_EXPR: | |
3491 | case TRUNC_DIV_EXPR: | |
3492 | case CEIL_DIV_EXPR: | |
3493 | case FLOOR_DIV_EXPR: | |
3494 | case ROUND_DIV_EXPR: | |
3495 | case TRUNC_MOD_EXPR: | |
3496 | case CEIL_MOD_EXPR: | |
3497 | case ROUND_MOD_EXPR: | |
3498 | case RDIV_EXPR: | |
3499 | case EXACT_DIV_EXPR: | |
3500 | case MIN_EXPR: | |
3501 | case MAX_EXPR: | |
3502 | case LSHIFT_EXPR: | |
3503 | case RSHIFT_EXPR: | |
3504 | case LROTATE_EXPR: | |
3505 | case RROTATE_EXPR: | |
3506 | case BIT_IOR_EXPR: | |
3507 | case BIT_XOR_EXPR: | |
3508 | case BIT_AND_EXPR: | |
3509 | case TRUTH_XOR_EXPR: | |
3510 | case LT_EXPR: | |
3511 | case LE_EXPR: | |
3512 | case GT_EXPR: | |
3513 | case GE_EXPR: | |
3514 | case EQ_EXPR: | |
3515 | case NE_EXPR: | |
3516 | case UNORDERED_EXPR: | |
3517 | case ORDERED_EXPR: | |
3518 | case UNLT_EXPR: | |
3519 | case UNLE_EXPR: | |
3520 | case UNGT_EXPR: | |
3521 | case UNGE_EXPR: | |
3522 | case UNEQ_EXPR: | |
3523 | case LTGT_EXPR: | |
3524 | case RANGE_EXPR: | |
3525 | case COMPLEX_EXPR: | |
1227ba74 | 3526 | r = cxx_eval_binary_expression (ctx, t, lval, |
09b42213 | 3527 | non_constant_p, overflow_p); |
3528 | break; | |
3529 | ||
3530 | /* fold can introduce non-IF versions of these; still treat them as | |
3531 | short-circuiting. */ | |
3532 | case TRUTH_AND_EXPR: | |
3533 | case TRUTH_ANDIF_EXPR: | |
cf72f34d | 3534 | r = cxx_eval_logical_expression (ctx, t, boolean_false_node, |
09b42213 | 3535 | boolean_true_node, |
1227ba74 | 3536 | lval, |
09b42213 | 3537 | non_constant_p, overflow_p); |
3538 | break; | |
3539 | ||
3540 | case TRUTH_OR_EXPR: | |
3541 | case TRUTH_ORIF_EXPR: | |
cf72f34d | 3542 | r = cxx_eval_logical_expression (ctx, t, boolean_true_node, |
09b42213 | 3543 | boolean_false_node, |
1227ba74 | 3544 | lval, |
09b42213 | 3545 | non_constant_p, overflow_p); |
3546 | break; | |
3547 | ||
3548 | case ARRAY_REF: | |
1227ba74 | 3549 | r = cxx_eval_array_reference (ctx, t, lval, |
09b42213 | 3550 | non_constant_p, overflow_p); |
3551 | break; | |
3552 | ||
3553 | case COMPONENT_REF: | |
3554 | if (is_overloaded_fn (t)) | |
3555 | { | |
3556 | /* We can only get here in checking mode via | |
3557 | build_non_dependent_expr, because any expression that | |
3558 | calls or takes the address of the function will have | |
3559 | pulled a FUNCTION_DECL out of the COMPONENT_REF. */ | |
f83e6885 | 3560 | gcc_checking_assert (ctx->quiet || errorcount); |
09b42213 | 3561 | *non_constant_p = true; |
3562 | return t; | |
3563 | } | |
1227ba74 | 3564 | r = cxx_eval_component_reference (ctx, t, lval, |
09b42213 | 3565 | non_constant_p, overflow_p); |
3566 | break; | |
3567 | ||
3568 | case BIT_FIELD_REF: | |
1227ba74 | 3569 | r = cxx_eval_bit_field_ref (ctx, t, lval, |
09b42213 | 3570 | non_constant_p, overflow_p); |
3571 | break; | |
3572 | ||
3573 | case COND_EXPR: | |
3574 | case VEC_COND_EXPR: | |
1227ba74 | 3575 | r = cxx_eval_conditional_expression (ctx, t, lval, |
00f21715 | 3576 | non_constant_p, overflow_p, |
3577 | jump_target); | |
09b42213 | 3578 | break; |
3579 | ||
3580 | case CONSTRUCTOR: | |
1a3631bc | 3581 | if (TREE_CONSTANT (t)) |
3582 | /* Don't re-process a constant CONSTRUCTOR, but do fold it to | |
3583 | VECTOR_CST if applicable. */ | |
3584 | return fold (t); | |
1227ba74 | 3585 | r = cxx_eval_bare_aggregate (ctx, t, lval, |
09b42213 | 3586 | non_constant_p, overflow_p); |
3587 | break; | |
3588 | ||
3589 | case VEC_INIT_EXPR: | |
3590 | /* We can get this in a defaulted constructor for a class with a | |
3591 | non-static data member of array type. Either the initializer will | |
3592 | be NULL, meaning default-initialization, or it will be an lvalue | |
3593 | or xvalue of the same type, meaning direct-initialization from the | |
3594 | corresponding member. */ | |
1227ba74 | 3595 | r = cxx_eval_vec_init (ctx, t, lval, |
09b42213 | 3596 | non_constant_p, overflow_p); |
3597 | break; | |
3598 | ||
3599 | case FMA_EXPR: | |
3600 | case VEC_PERM_EXPR: | |
1227ba74 | 3601 | r = cxx_eval_trinary_expression (ctx, t, lval, |
09b42213 | 3602 | non_constant_p, overflow_p); |
3603 | break; | |
3604 | ||
3605 | case CONVERT_EXPR: | |
3606 | case VIEW_CONVERT_EXPR: | |
3607 | case NOP_EXPR: | |
d2c63826 | 3608 | case UNARY_PLUS_EXPR: |
09b42213 | 3609 | { |
d2c63826 | 3610 | enum tree_code tcode = TREE_CODE (t); |
09b42213 | 3611 | tree oldop = TREE_OPERAND (t, 0); |
d2c63826 | 3612 | |
cf72f34d | 3613 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 3614 | lval, |
b2a43197 | 3615 | non_constant_p, overflow_p); |
09b42213 | 3616 | if (*non_constant_p) |
3617 | return t; | |
f16ed232 | 3618 | tree type = TREE_TYPE (t); |
3619 | if (TREE_CODE (op) == PTRMEM_CST | |
3620 | && !TYPE_PTRMEM_P (type)) | |
3621 | op = cplus_expand_constant (op); | |
3622 | if (POINTER_TYPE_P (type) | |
09b42213 | 3623 | && TREE_CODE (op) == INTEGER_CST |
3624 | && !integer_zerop (op)) | |
3625 | { | |
f83e6885 | 3626 | if (!ctx->quiet) |
09b42213 | 3627 | error_at (EXPR_LOC_OR_LOC (t, input_location), |
3628 | "reinterpret_cast from integer to pointer"); | |
3629 | *non_constant_p = true; | |
3630 | return t; | |
3631 | } | |
d2c63826 | 3632 | if (op == oldop && tcode != UNARY_PLUS_EXPR) |
09b42213 | 3633 | /* We didn't fold at the top so we could check for ptr-int |
3634 | conversion. */ | |
3635 | return fold (t); | |
d2c63826 | 3636 | if (tcode == UNARY_PLUS_EXPR) |
3637 | r = fold_convert (TREE_TYPE (t), op); | |
3638 | else | |
3639 | r = fold_build1 (tcode, type, op); | |
09b42213 | 3640 | /* Conversion of an out-of-range value has implementation-defined |
3641 | behavior; the language considers it different from arithmetic | |
3642 | overflow, which is undefined. */ | |
3643 | if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op)) | |
3644 | TREE_OVERFLOW (r) = false; | |
3645 | } | |
3646 | break; | |
3647 | ||
3648 | case EMPTY_CLASS_EXPR: | |
3649 | /* This is good enough for a function argument that might not get | |
3650 | used, and they can't do anything with it, so just return it. */ | |
3651 | return t; | |
3652 | ||
9c96033c | 3653 | case STATEMENT_LIST: |
00f21715 | 3654 | new_ctx = *ctx; |
3655 | new_ctx.ctor = new_ctx.object = NULL_TREE; | |
f83e6885 | 3656 | return cxx_eval_statement_list (&new_ctx, t, |
00f21715 | 3657 | non_constant_p, overflow_p, jump_target); |
9c96033c | 3658 | |
3659 | case BIND_EXPR: | |
3660 | return cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t), | |
1227ba74 | 3661 | lval, |
00f21715 | 3662 | non_constant_p, overflow_p, |
3663 | jump_target); | |
9c96033c | 3664 | |
09b42213 | 3665 | case PREINCREMENT_EXPR: |
3666 | case POSTINCREMENT_EXPR: | |
3667 | case PREDECREMENT_EXPR: | |
3668 | case POSTDECREMENT_EXPR: | |
f83e6885 | 3669 | return cxx_eval_increment_expression (ctx, t, |
1227ba74 | 3670 | lval, non_constant_p, overflow_p); |
9c96033c | 3671 | |
3672 | case LAMBDA_EXPR: | |
09b42213 | 3673 | case NEW_EXPR: |
3674 | case VEC_NEW_EXPR: | |
3675 | case DELETE_EXPR: | |
3676 | case VEC_DELETE_EXPR: | |
3677 | case THROW_EXPR: | |
09b42213 | 3678 | case MODOP_EXPR: |
3679 | /* GCC internal stuff. */ | |
3680 | case VA_ARG_EXPR: | |
3681 | case OBJ_TYPE_REF: | |
3682 | case WITH_CLEANUP_EXPR: | |
09b42213 | 3683 | case NON_DEPENDENT_EXPR: |
3684 | case BASELINK: | |
09b42213 | 3685 | case OFFSET_REF: |
f83e6885 | 3686 | if (!ctx->quiet) |
09b42213 | 3687 | error_at (EXPR_LOC_OR_LOC (t, input_location), |
3688 | "expression %qE is not a constant-expression", t); | |
3689 | *non_constant_p = true; | |
3690 | break; | |
3691 | ||
cf72f34d | 3692 | case PLACEHOLDER_EXPR: |
fe235c02 | 3693 | if (!ctx || !ctx->ctor || (lval && !ctx->object) |
3694 | || !(same_type_ignoring_top_level_qualifiers_p | |
3695 | (TREE_TYPE (t), TREE_TYPE (ctx->ctor)))) | |
cf72f34d | 3696 | { |
3697 | /* A placeholder without a referent. We can get here when | |
3698 | checking whether NSDMIs are noexcept, or in massage_init_elt; | |
3699 | just say it's non-constant for now. */ | |
f83e6885 | 3700 | gcc_assert (ctx->quiet); |
cf72f34d | 3701 | *non_constant_p = true; |
3702 | break; | |
3703 | } | |
3704 | else | |
3705 | { | |
3706 | /* Use of the value or address of the current object. We could | |
3707 | use ctx->object unconditionally, but using ctx->ctor when we | |
3708 | can is a minor optimization. */ | |
1227ba74 | 3709 | tree ctor = lval ? ctx->object : ctx->ctor; |
cf72f34d | 3710 | return cxx_eval_constant_expression |
1227ba74 | 3711 | (ctx, ctor, lval, |
b2a43197 | 3712 | non_constant_p, overflow_p); |
cf72f34d | 3713 | } |
3714 | break; | |
3715 | ||
9c96033c | 3716 | case GOTO_EXPR: |
00f21715 | 3717 | *jump_target = TREE_OPERAND (t, 0); |
3718 | gcc_assert (breaks (jump_target) || continues (jump_target)); | |
3719 | break; | |
3720 | ||
9c96033c | 3721 | case LOOP_EXPR: |
f83e6885 | 3722 | cxx_eval_loop_expr (ctx, t, |
00f21715 | 3723 | non_constant_p, overflow_p, jump_target); |
3724 | break; | |
3725 | ||
9c96033c | 3726 | case SWITCH_EXPR: |
f83e6885 | 3727 | cxx_eval_switch_expr (ctx, t, |
00f21715 | 3728 | non_constant_p, overflow_p, jump_target); |
9c96033c | 3729 | break; |
3730 | ||
56c12fd4 | 3731 | case REQUIRES_EXPR: |
3732 | /* It's possible to get a requires-expression in a constant | |
3733 | expression. For example: | |
3734 | ||
3735 | template<typename T> concept bool C() { | |
3736 | return requires (T t) { t; }; | |
3737 | } | |
3738 | ||
3739 | template<typename T> requires !C<T>() void f(T); | |
3740 | ||
3741 | Normalization leaves f with the associated constraint | |
3742 | '!requires (T t) { ... }' which is not transformed into | |
3743 | a constraint. */ | |
3744 | if (!processing_template_decl) | |
3745 | return evaluate_constraint_expression (t, NULL_TREE); | |
3746 | else | |
3747 | *non_constant_p = true; | |
3748 | return t; | |
3749 | ||
09b42213 | 3750 | default: |
b9a3af23 | 3751 | if (STATEMENT_CODE_P (TREE_CODE (t))) |
3752 | { | |
3753 | /* This function doesn't know how to deal with pre-genericize | |
3754 | statements; this can only happen with statement-expressions, | |
3755 | so for now just fail. */ | |
3756 | if (!ctx->quiet) | |
3757 | error_at (EXPR_LOCATION (t), | |
3758 | "statement is not a constant-expression"); | |
3759 | } | |
3760 | else | |
3761 | internal_error ("unexpected expression %qE of kind %s", t, | |
3762 | get_tree_code_name (TREE_CODE (t))); | |
09b42213 | 3763 | *non_constant_p = true; |
3764 | break; | |
3765 | } | |
3766 | ||
3767 | if (r == error_mark_node) | |
3768 | *non_constant_p = true; | |
3769 | ||
3770 | if (*non_constant_p) | |
3771 | return t; | |
3772 | else | |
3773 | return r; | |
3774 | } | |
3775 | ||
3776 | static tree | |
cf72f34d | 3777 | cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, |
2055d27a | 3778 | bool strict = true, tree object = NULL_TREE) |
09b42213 | 3779 | { |
3780 | bool non_constant_p = false; | |
3781 | bool overflow_p = false; | |
cf72f34d | 3782 | hash_map<tree,tree> map; |
f9885b8a | 3783 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, allow_non_constant, strict }; |
cf72f34d | 3784 | tree type = initialized_type (t); |
cf72f34d | 3785 | tree r = t; |
3786 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) | |
3787 | { | |
3788 | /* In C++14 an NSDMI can participate in aggregate initialization, | |
3789 | and can refer to the address of the object being initialized, so | |
3790 | we need to pass in the relevant VAR_DECL if we want to do the | |
3791 | evaluation in a single pass. The evaluation will dynamically | |
3792 | update ctx.values for the VAR_DECL. We use the same strategy | |
3793 | for C++11 constexpr constructors that refer to the object being | |
3794 | initialized. */ | |
3795 | ctx.ctor = build_constructor (type, NULL); | |
3796 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctx.ctor) = true; | |
9c96033c | 3797 | if (!object) |
3798 | { | |
3799 | if (TREE_CODE (t) == TARGET_EXPR) | |
3800 | object = TARGET_EXPR_SLOT (t); | |
3801 | else if (TREE_CODE (t) == AGGR_INIT_EXPR) | |
3802 | object = AGGR_INIT_EXPR_SLOT (t); | |
3803 | } | |
cf72f34d | 3804 | ctx.object = object; |
3805 | if (object) | |
3806 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
3807 | (type, TREE_TYPE (object))); | |
3808 | if (object && DECL_P (object)) | |
3809 | map.put (object, ctx.ctor); | |
3810 | if (TREE_CODE (r) == TARGET_EXPR) | |
3811 | /* Avoid creating another CONSTRUCTOR when we expand the | |
3812 | TARGET_EXPR. */ | |
3813 | r = TARGET_EXPR_INITIAL (r); | |
3814 | } | |
3815 | ||
f83e6885 | 3816 | r = cxx_eval_constant_expression (&ctx, r, |
b2a43197 | 3817 | false, &non_constant_p, &overflow_p); |
09b42213 | 3818 | |
3819 | verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); | |
3820 | ||
bbcc9042 | 3821 | /* Mutable logic is a bit tricky: we want to allow initialization of |
3822 | constexpr variables with mutable members, but we can't copy those | |
3823 | members to another constexpr variable. */ | |
3824 | if (TREE_CODE (r) == CONSTRUCTOR | |
3825 | && CONSTRUCTOR_MUTABLE_POISON (r)) | |
09b42213 | 3826 | { |
09b42213 | 3827 | if (!allow_non_constant) |
bbcc9042 | 3828 | error ("%qE is not a constant expression because it refers to " |
3829 | "mutable subobjects of %qT", t, type); | |
09b42213 | 3830 | non_constant_p = true; |
3831 | } | |
3832 | ||
3833 | /* Technically we should check this for all subexpressions, but that | |
3834 | runs into problems with our internal representation of pointer | |
3835 | subtraction and the 5.19 rules are still in flux. */ | |
3836 | if (CONVERT_EXPR_CODE_P (TREE_CODE (r)) | |
3837 | && ARITHMETIC_TYPE_P (TREE_TYPE (r)) | |
3838 | && TREE_CODE (TREE_OPERAND (r, 0)) == ADDR_EXPR) | |
3839 | { | |
3840 | if (!allow_non_constant) | |
3841 | error ("conversion from pointer type %qT " | |
3842 | "to arithmetic type %qT in a constant-expression", | |
3843 | TREE_TYPE (TREE_OPERAND (r, 0)), TREE_TYPE (r)); | |
3844 | non_constant_p = true; | |
3845 | } | |
3846 | ||
3847 | if (!non_constant_p && overflow_p) | |
3848 | non_constant_p = true; | |
3849 | ||
3850 | if (non_constant_p && !allow_non_constant) | |
3851 | return error_mark_node; | |
3852 | else if (non_constant_p && TREE_CONSTANT (r)) | |
3853 | { | |
3854 | /* This isn't actually constant, so unset TREE_CONSTANT. */ | |
3855 | if (EXPR_P (r)) | |
3856 | r = copy_node (r); | |
3857 | else if (TREE_CODE (r) == CONSTRUCTOR) | |
3858 | r = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (r), r); | |
3859 | else | |
3860 | r = build_nop (TREE_TYPE (r), r); | |
3861 | TREE_CONSTANT (r) = false; | |
3862 | } | |
3863 | else if (non_constant_p || r == t) | |
3864 | return t; | |
3865 | ||
3866 | if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r))) | |
3867 | { | |
3868 | if (TREE_CODE (t) == TARGET_EXPR | |
3869 | && TARGET_EXPR_INITIAL (t) == r) | |
3870 | return t; | |
3871 | else | |
3872 | { | |
3873 | r = get_target_expr (r); | |
3874 | TREE_CONSTANT (r) = true; | |
3875 | return r; | |
3876 | } | |
3877 | } | |
3878 | else | |
3879 | return r; | |
3880 | } | |
3881 | ||
3882 | /* Returns true if T is a valid subexpression of a constant expression, | |
3883 | even if it isn't itself a constant expression. */ | |
3884 | ||
3885 | bool | |
3886 | is_sub_constant_expr (tree t) | |
3887 | { | |
3888 | bool non_constant_p = false; | |
3889 | bool overflow_p = false; | |
cf72f34d | 3890 | hash_map <tree, tree> map; |
f9885b8a | 3891 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, true, true }; |
f83e6885 | 3892 | cxx_eval_constant_expression (&ctx, t, false, &non_constant_p, |
b2a43197 | 3893 | &overflow_p); |
09b42213 | 3894 | return !non_constant_p && !overflow_p; |
3895 | } | |
3896 | ||
3897 | /* If T represents a constant expression returns its reduced value. | |
3898 | Otherwise return error_mark_node. If T is dependent, then | |
3899 | return NULL. */ | |
3900 | ||
3901 | tree | |
cf72f34d | 3902 | cxx_constant_value (tree t, tree decl) |
09b42213 | 3903 | { |
2055d27a | 3904 | return cxx_eval_outermost_constant_expr (t, false, true, decl); |
09b42213 | 3905 | } |
3906 | ||
d2c63826 | 3907 | /* Helper routine for fold_simple function. Either return simplified |
3908 | expression T, otherwise NULL_TREE. | |
3909 | In contrast to cp_fully_fold, and to maybe_constant_value, we try to fold | |
3910 | even if we are within template-declaration. So be careful on call, as in | |
3911 | such case types can be undefined. */ | |
3912 | ||
3913 | static tree | |
3914 | fold_simple_1 (tree t) | |
3915 | { | |
3916 | tree op1; | |
3917 | enum tree_code code = TREE_CODE (t); | |
3918 | ||
3919 | switch (code) | |
3920 | { | |
3921 | case INTEGER_CST: | |
3922 | case REAL_CST: | |
3923 | case VECTOR_CST: | |
3924 | case FIXED_CST: | |
3925 | case COMPLEX_CST: | |
3926 | return t; | |
3927 | ||
3928 | case SIZEOF_EXPR: | |
3929 | return fold_sizeof_expr (t); | |
3930 | ||
3931 | case ABS_EXPR: | |
3932 | case CONJ_EXPR: | |
3933 | case REALPART_EXPR: | |
3934 | case IMAGPART_EXPR: | |
3935 | case NEGATE_EXPR: | |
3936 | case BIT_NOT_EXPR: | |
3937 | case TRUTH_NOT_EXPR: | |
3938 | case NOP_EXPR: | |
3939 | case VIEW_CONVERT_EXPR: | |
3940 | case CONVERT_EXPR: | |
3941 | case FLOAT_EXPR: | |
3942 | case FIX_TRUNC_EXPR: | |
3943 | case FIXED_CONVERT_EXPR: | |
3944 | case ADDR_SPACE_CONVERT_EXPR: | |
3945 | ||
3946 | op1 = TREE_OPERAND (t, 0); | |
3947 | ||
3948 | t = const_unop (code, TREE_TYPE (t), op1); | |
3949 | if (!t) | |
3950 | return NULL_TREE; | |
3951 | ||
3952 | if (CONVERT_EXPR_CODE_P (code) | |
3953 | && TREE_OVERFLOW_P (t) && !TREE_OVERFLOW_P (op1)) | |
3954 | TREE_OVERFLOW (t) = false; | |
3955 | return t; | |
3956 | ||
3957 | default: | |
3958 | return NULL_TREE; | |
3959 | } | |
3960 | } | |
3961 | ||
3962 | /* If T is a simple constant expression, returns its simplified value. | |
3963 | Otherwise returns T. In contrast to maybe_constant_value do we | |
3964 | simplify only few operations on constant-expressions, and we don't | |
3965 | try to simplify constexpressions. */ | |
3966 | ||
3967 | tree | |
3968 | fold_simple (tree t) | |
3969 | { | |
3970 | tree r = NULL_TREE; | |
3971 | if (processing_template_decl) | |
3972 | return t; | |
3973 | ||
3974 | r = fold_simple_1 (t); | |
3975 | if (!r) | |
3976 | r = t; | |
3977 | ||
3978 | return r; | |
3979 | } | |
3980 | ||
09b42213 | 3981 | /* If T is a constant expression, returns its reduced value. |
3982 | Otherwise, if T does not have TREE_CONSTANT set, returns T. | |
3983 | Otherwise, returns a version of T without TREE_CONSTANT. */ | |
3984 | ||
d2c63826 | 3985 | static tree |
3986 | maybe_constant_value_1 (tree t, tree decl) | |
09b42213 | 3987 | { |
3988 | tree r; | |
3989 | ||
3990 | if (instantiation_dependent_expression_p (t) | |
3991 | || type_unknown_p (t) | |
3992 | || BRACE_ENCLOSED_INITIALIZER_P (t) | |
3993 | || !potential_constant_expression (t)) | |
3994 | { | |
3995 | if (TREE_OVERFLOW_P (t)) | |
3996 | { | |
3997 | t = build_nop (TREE_TYPE (t), t); | |
3998 | TREE_CONSTANT (t) = false; | |
3999 | } | |
4000 | return t; | |
4001 | } | |
4002 | ||
2055d27a | 4003 | r = cxx_eval_outermost_constant_expr (t, true, true, decl); |
5e8689fb | 4004 | gcc_checking_assert (r == t |
4005 | || CONVERT_EXPR_P (t) | |
4006 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
4007 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
4008 | || !cp_tree_equal (r, t)); | |
09b42213 | 4009 | return r; |
4010 | } | |
4011 | ||
d2c63826 | 4012 | static GTY((cache, deletable)) cache_map cv_cache; |
4013 | ||
4014 | /* If T is a constant expression, returns its reduced value. | |
4015 | Otherwise, if T does not have TREE_CONSTANT set, returns T. | |
4016 | Otherwise, returns a version of T without TREE_CONSTANT. */ | |
4017 | ||
4018 | tree | |
4019 | maybe_constant_value (tree t, tree decl) | |
4020 | { | |
4021 | tree ret = cv_cache.get (t); | |
4022 | if (!ret) | |
4023 | { | |
4024 | ret = maybe_constant_value_1 (t, decl); | |
4025 | cv_cache.put (t, ret); | |
4026 | } | |
4027 | return ret; | |
4028 | } | |
4029 | ||
21131a05 | 4030 | /* Like maybe_constant_value but first fully instantiate the argument. |
4031 | ||
4032 | Note: this is equivalent to instantiate_non_dependent_expr_sfinae | |
4033 | (t, tf_none) followed by maybe_constant_value but is more efficient, | |
4034 | because calls instantiation_dependent_expression_p and | |
4035 | potential_constant_expression at most once. */ | |
4036 | ||
4037 | tree | |
4038 | fold_non_dependent_expr (tree t) | |
4039 | { | |
4040 | if (t == NULL_TREE) | |
4041 | return NULL_TREE; | |
4042 | ||
4043 | /* If we're in a template, but T isn't value dependent, simplify | |
4044 | it. We're supposed to treat: | |
4045 | ||
4046 | template <typename T> void f(T[1 + 1]); | |
4047 | template <typename T> void f(T[2]); | |
4048 | ||
4049 | as two declarations of the same function, for example. */ | |
4050 | if (processing_template_decl) | |
4051 | { | |
4052 | if (!instantiation_dependent_expression_p (t) | |
4053 | && potential_constant_expression (t)) | |
4054 | { | |
c8a9f04c | 4055 | processing_template_decl_sentinel s; |
4056 | t = instantiate_non_dependent_expr_internal (t, tf_none); | |
21131a05 | 4057 | |
4058 | if (type_unknown_p (t) | |
4059 | || BRACE_ENCLOSED_INITIALIZER_P (t)) | |
4060 | { | |
4061 | if (TREE_OVERFLOW_P (t)) | |
4062 | { | |
4063 | t = build_nop (TREE_TYPE (t), t); | |
4064 | TREE_CONSTANT (t) = false; | |
4065 | } | |
4066 | return t; | |
4067 | } | |
4068 | ||
2055d27a | 4069 | tree r = cxx_eval_outermost_constant_expr (t, true, true, NULL_TREE); |
21131a05 | 4070 | /* cp_tree_equal looks through NOPs, so allow them. */ |
5e8689fb | 4071 | gcc_checking_assert (r == t |
4072 | || CONVERT_EXPR_P (t) | |
4073 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
4074 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
4075 | || !cp_tree_equal (r, t)); | |
21131a05 | 4076 | return r; |
4077 | } | |
4078 | else if (TREE_OVERFLOW_P (t)) | |
4079 | { | |
4080 | t = build_nop (TREE_TYPE (t), t); | |
4081 | TREE_CONSTANT (t) = false; | |
4082 | } | |
4083 | return t; | |
4084 | } | |
4085 | ||
4086 | return maybe_constant_value (t); | |
4087 | } | |
4088 | ||
09b42213 | 4089 | /* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather |
4090 | than wrapped in a TARGET_EXPR. */ | |
4091 | ||
4092 | tree | |
cf72f34d | 4093 | maybe_constant_init (tree t, tree decl) |
09b42213 | 4094 | { |
d2c63826 | 4095 | if (!t) |
4096 | return t; | |
09b42213 | 4097 | if (TREE_CODE (t) == EXPR_STMT) |
4098 | t = TREE_OPERAND (t, 0); | |
4099 | if (TREE_CODE (t) == CONVERT_EXPR | |
4100 | && VOID_TYPE_P (TREE_TYPE (t))) | |
4101 | t = TREE_OPERAND (t, 0); | |
9c96033c | 4102 | if (TREE_CODE (t) == INIT_EXPR) |
4103 | t = TREE_OPERAND (t, 1); | |
2055d27a | 4104 | if (instantiation_dependent_expression_p (t) |
4105 | || type_unknown_p (t) | |
4106 | || BRACE_ENCLOSED_INITIALIZER_P (t) | |
4107 | || !potential_static_init_expression (t)) | |
4108 | /* Don't try to evaluate it. */; | |
4109 | else | |
4110 | t = cxx_eval_outermost_constant_expr (t, true, false, decl); | |
09b42213 | 4111 | if (TREE_CODE (t) == TARGET_EXPR) |
4112 | { | |
4113 | tree init = TARGET_EXPR_INITIAL (t); | |
4114 | if (TREE_CODE (init) == CONSTRUCTOR) | |
4115 | t = init; | |
4116 | } | |
4117 | return t; | |
4118 | } | |
4119 | ||
4120 | #if 0 | |
4121 | /* FIXME see ADDR_EXPR section in potential_constant_expression_1. */ | |
4122 | /* Return true if the object referred to by REF has automatic or thread | |
4123 | local storage. */ | |
4124 | ||
4125 | enum { ck_ok, ck_bad, ck_unknown }; | |
4126 | static int | |
4127 | check_automatic_or_tls (tree ref) | |
4128 | { | |
3754d046 | 4129 | machine_mode mode; |
09b42213 | 4130 | HOST_WIDE_INT bitsize, bitpos; |
4131 | tree offset; | |
4132 | int volatilep = 0, unsignedp = 0; | |
4133 | tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset, | |
4134 | &mode, &unsignedp, &volatilep, false); | |
4135 | duration_kind dk; | |
4136 | ||
4137 | /* If there isn't a decl in the middle, we don't know the linkage here, | |
4138 | and this isn't a constant expression anyway. */ | |
4139 | if (!DECL_P (decl)) | |
4140 | return ck_unknown; | |
4141 | dk = decl_storage_duration (decl); | |
4142 | return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok; | |
4143 | } | |
4144 | #endif | |
4145 | ||
4146 | /* Return true if T denotes a potentially constant expression. Issue | |
4147 | diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true, | |
4148 | an lvalue-rvalue conversion is implied. | |
4149 | ||
4150 | C++0x [expr.const] used to say | |
4151 | ||
4152 | 6 An expression is a potential constant expression if it is | |
4153 | a constant expression where all occurrences of function | |
4154 | parameters are replaced by arbitrary constant expressions | |
4155 | of the appropriate type. | |
4156 | ||
4157 | 2 A conditional expression is a constant expression unless it | |
4158 | involves one of the following as a potentially evaluated | |
4159 | subexpression (3.2), but subexpressions of logical AND (5.14), | |
4160 | logical OR (5.15), and conditional (5.16) operations that are | |
4161 | not evaluated are not considered. */ | |
4162 | ||
4163 | static bool | |
2055d27a | 4164 | potential_constant_expression_1 (tree t, bool want_rval, bool strict, |
4165 | tsubst_flags_t flags) | |
09b42213 | 4166 | { |
2055d27a | 4167 | #define RECUR(T,RV) potential_constant_expression_1 ((T), (RV), strict, flags) |
09b42213 | 4168 | enum { any = false, rval = true }; |
4169 | int i; | |
4170 | tree tmp; | |
4171 | ||
4172 | if (t == error_mark_node) | |
4173 | return false; | |
4174 | if (t == NULL_TREE) | |
4175 | return true; | |
eade0940 | 4176 | if (TREE_THIS_VOLATILE (t) && !DECL_P (t)) |
09b42213 | 4177 | { |
4178 | if (flags & tf_error) | |
4179 | error ("expression %qE has side-effects", t); | |
4180 | return false; | |
4181 | } | |
4182 | if (CONSTANT_CLASS_P (t)) | |
4183 | return true; | |
4184 | ||
4185 | switch (TREE_CODE (t)) | |
4186 | { | |
4187 | case FUNCTION_DECL: | |
4188 | case BASELINK: | |
4189 | case TEMPLATE_DECL: | |
4190 | case OVERLOAD: | |
4191 | case TEMPLATE_ID_EXPR: | |
4192 | case LABEL_DECL: | |
4193 | case LABEL_EXPR: | |
9c96033c | 4194 | case CASE_LABEL_EXPR: |
09b42213 | 4195 | case CONST_DECL: |
4196 | case SIZEOF_EXPR: | |
4197 | case ALIGNOF_EXPR: | |
4198 | case OFFSETOF_EXPR: | |
4199 | case NOEXCEPT_EXPR: | |
4200 | case TEMPLATE_PARM_INDEX: | |
4201 | case TRAIT_EXPR: | |
4202 | case IDENTIFIER_NODE: | |
4203 | case USERDEF_LITERAL: | |
4204 | /* We can see a FIELD_DECL in a pointer-to-member expression. */ | |
4205 | case FIELD_DECL: | |
4206 | case PARM_DECL: | |
d2c63826 | 4207 | case RESULT_DECL: |
09b42213 | 4208 | case USING_DECL: |
9c96033c | 4209 | case USING_STMT: |
cf72f34d | 4210 | case PLACEHOLDER_EXPR: |
9c96033c | 4211 | case BREAK_STMT: |
4212 | case CONTINUE_STMT: | |
56c12fd4 | 4213 | case REQUIRES_EXPR: |
09b42213 | 4214 | return true; |
4215 | ||
4216 | case AGGR_INIT_EXPR: | |
4217 | case CALL_EXPR: | |
4218 | /* -- an invocation of a function other than a constexpr function | |
4219 | or a constexpr constructor. */ | |
4220 | { | |
4221 | tree fun = get_function_named_in_call (t); | |
4222 | const int nargs = call_expr_nargs (t); | |
4223 | i = 0; | |
4224 | ||
9c96033c | 4225 | if (fun == NULL_TREE) |
4226 | { | |
32cf7025 | 4227 | if (TREE_CODE (t) == CALL_EXPR |
4228 | && CALL_EXPR_FN (t) == NULL_TREE) | |
4229 | switch (CALL_EXPR_IFN (t)) | |
4230 | { | |
4231 | /* These should be ignored, they are optimized away from | |
4232 | constexpr functions. */ | |
4233 | case IFN_UBSAN_NULL: | |
4234 | case IFN_UBSAN_BOUNDS: | |
4235 | case IFN_UBSAN_VPTR: | |
4236 | return true; | |
4237 | default: | |
4238 | break; | |
4239 | } | |
9c96033c | 4240 | /* fold_call_expr can't do anything with IFN calls. */ |
4241 | if (flags & tf_error) | |
4242 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4243 | "call to internal function"); | |
4244 | return false; | |
4245 | } | |
09b42213 | 4246 | if (is_overloaded_fn (fun)) |
4247 | { | |
4248 | if (TREE_CODE (fun) == FUNCTION_DECL) | |
4249 | { | |
4250 | if (builtin_valid_in_constant_expr_p (fun)) | |
4251 | return true; | |
4252 | if (!DECL_DECLARED_CONSTEXPR_P (fun) | |
4253 | /* Allow any built-in function; if the expansion | |
4254 | isn't constant, we'll deal with that then. */ | |
4255 | && !is_builtin_fn (fun)) | |
4256 | { | |
4257 | if (flags & tf_error) | |
4258 | { | |
4259 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4260 | "call to non-constexpr function %qD", fun); | |
4261 | explain_invalid_constexpr_fn (fun); | |
4262 | } | |
4263 | return false; | |
4264 | } | |
4265 | /* A call to a non-static member function takes the address | |
4266 | of the object as the first argument. But in a constant | |
4267 | expression the address will be folded away, so look | |
4268 | through it now. */ | |
4269 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
4270 | && !DECL_CONSTRUCTOR_P (fun)) | |
4271 | { | |
4272 | tree x = get_nth_callarg (t, 0); | |
4273 | if (is_this_parameter (x)) | |
cf72f34d | 4274 | return true; |
2055d27a | 4275 | else if (!RECUR (x, rval)) |
09b42213 | 4276 | return false; |
4277 | i = 1; | |
4278 | } | |
4279 | } | |
4280 | else | |
4281 | { | |
2055d27a | 4282 | if (!RECUR (fun, true)) |
09b42213 | 4283 | return false; |
4284 | fun = get_first_fn (fun); | |
4285 | } | |
4286 | /* Skip initial arguments to base constructors. */ | |
4287 | if (DECL_BASE_CONSTRUCTOR_P (fun)) | |
4288 | i = num_artificial_parms_for (fun); | |
4289 | fun = DECL_ORIGIN (fun); | |
4290 | } | |
4291 | else | |
4292 | { | |
2055d27a | 4293 | if (RECUR (fun, rval)) |
09b42213 | 4294 | /* Might end up being a constant function pointer. */; |
4295 | else | |
4296 | return false; | |
4297 | } | |
4298 | for (; i < nargs; ++i) | |
4299 | { | |
4300 | tree x = get_nth_callarg (t, i); | |
b2742b58 | 4301 | /* In a template, reference arguments haven't been converted to |
4302 | REFERENCE_TYPE and we might not even know if the parameter | |
4303 | is a reference, so accept lvalue constants too. */ | |
4304 | bool rv = processing_template_decl ? any : rval; | |
4305 | if (!RECUR (x, rv)) | |
09b42213 | 4306 | return false; |
4307 | } | |
4308 | return true; | |
4309 | } | |
4310 | ||
4311 | case NON_LVALUE_EXPR: | |
4312 | /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to | |
4313 | -- an lvalue of integral type that refers to a non-volatile | |
4314 | const variable or static data member initialized with | |
4315 | constant expressions, or | |
4316 | ||
4317 | -- an lvalue of literal type that refers to non-volatile | |
4318 | object defined with constexpr, or that refers to a | |
4319 | sub-object of such an object; */ | |
2055d27a | 4320 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 4321 | |
4322 | case VAR_DECL: | |
2055d27a | 4323 | if (want_rval |
4324 | && !decl_constant_var_p (t) | |
4325 | && (strict | |
4326 | || !CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (t)) | |
4327 | || !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (t)) | |
09b42213 | 4328 | && !var_in_constexpr_fn (t) |
dff5042c | 4329 | && !type_dependent_expression_p (t)) |
09b42213 | 4330 | { |
4331 | if (flags & tf_error) | |
4332 | non_const_var_error (t); | |
4333 | return false; | |
4334 | } | |
4335 | return true; | |
4336 | ||
4337 | case NOP_EXPR: | |
4338 | case CONVERT_EXPR: | |
4339 | case VIEW_CONVERT_EXPR: | |
4340 | /* -- a reinterpret_cast. FIXME not implemented, and this rule | |
4341 | may change to something more specific to type-punning (DR 1312). */ | |
4342 | { | |
4343 | tree from = TREE_OPERAND (t, 0); | |
4344 | if (POINTER_TYPE_P (TREE_TYPE (t)) | |
4345 | && TREE_CODE (from) == INTEGER_CST | |
4346 | && !integer_zerop (from)) | |
4347 | { | |
4348 | if (flags & tf_error) | |
4349 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4350 | "reinterpret_cast from integer to pointer"); | |
4351 | return false; | |
4352 | } | |
2055d27a | 4353 | return (RECUR (from, TREE_CODE (t) != VIEW_CONVERT_EXPR)); |
09b42213 | 4354 | } |
4355 | ||
4356 | case ADDR_EXPR: | |
4357 | /* -- a unary operator & that is applied to an lvalue that | |
4358 | designates an object with thread or automatic storage | |
4359 | duration; */ | |
4360 | t = TREE_OPERAND (t, 0); | |
4361 | ||
4362 | if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t)) | |
4363 | /* A pointer-to-member constant. */ | |
4364 | return true; | |
4365 | ||
4366 | #if 0 | |
4367 | /* FIXME adjust when issue 1197 is fully resolved. For now don't do | |
4368 | any checking here, as we might dereference the pointer later. If | |
4369 | we remove this code, also remove check_automatic_or_tls. */ | |
4370 | i = check_automatic_or_tls (t); | |
4371 | if (i == ck_ok) | |
4372 | return true; | |
4373 | if (i == ck_bad) | |
4374 | { | |
4375 | if (flags & tf_error) | |
4376 | error ("address-of an object %qE with thread local or " | |
4377 | "automatic storage is not a constant expression", t); | |
4378 | return false; | |
4379 | } | |
4380 | #endif | |
2055d27a | 4381 | return RECUR (t, any); |
09b42213 | 4382 | |
4383 | case COMPONENT_REF: | |
4384 | case BIT_FIELD_REF: | |
4385 | case ARROW_EXPR: | |
4386 | case OFFSET_REF: | |
4387 | /* -- a class member access unless its postfix-expression is | |
4388 | of literal type or of pointer to literal type. */ | |
4389 | /* This test would be redundant, as it follows from the | |
4390 | postfix-expression being a potential constant expression. */ | |
eade0940 | 4391 | if (type_unknown_p (t)) |
4392 | return true; | |
2055d27a | 4393 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 4394 | |
4395 | case EXPR_PACK_EXPANSION: | |
2055d27a | 4396 | return RECUR (PACK_EXPANSION_PATTERN (t), want_rval); |
09b42213 | 4397 | |
4398 | case INDIRECT_REF: | |
4399 | { | |
4400 | tree x = TREE_OPERAND (t, 0); | |
4401 | STRIP_NOPS (x); | |
4402 | if (is_this_parameter (x)) | |
4403 | { | |
4404 | if (DECL_CONTEXT (x) | |
4405 | && !DECL_DECLARED_CONSTEXPR_P (DECL_CONTEXT (x))) | |
4406 | { | |
4407 | if (flags & tf_error) | |
4408 | error ("use of %<this%> in a constant expression"); | |
4409 | return false; | |
4410 | } | |
09b42213 | 4411 | return true; |
4412 | } | |
2055d27a | 4413 | return RECUR (x, rval); |
09b42213 | 4414 | } |
4415 | ||
9c96033c | 4416 | case STATEMENT_LIST: |
4417 | { | |
4418 | tree_stmt_iterator i; | |
4419 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
4420 | { | |
2055d27a | 4421 | if (!RECUR (tsi_stmt (i), any)) |
9c96033c | 4422 | return false; |
4423 | } | |
4424 | return true; | |
4425 | } | |
4426 | break; | |
4427 | ||
4428 | case MODIFY_EXPR: | |
4429 | if (cxx_dialect < cxx14) | |
4430 | goto fail; | |
2055d27a | 4431 | if (!RECUR (TREE_OPERAND (t, 0), any)) |
9c96033c | 4432 | return false; |
2055d27a | 4433 | if (!RECUR (TREE_OPERAND (t, 1), rval)) |
9c96033c | 4434 | return false; |
4435 | return true; | |
4436 | ||
4437 | case MODOP_EXPR: | |
4438 | if (cxx_dialect < cxx14) | |
4439 | goto fail; | |
2055d27a | 4440 | if (!RECUR (TREE_OPERAND (t, 0), rval)) |
9c96033c | 4441 | return false; |
2055d27a | 4442 | if (!RECUR (TREE_OPERAND (t, 2), rval)) |
9c96033c | 4443 | return false; |
4444 | return true; | |
4445 | ||
9c96033c | 4446 | case DO_STMT: |
2055d27a | 4447 | if (!RECUR (DO_COND (t), rval)) |
9c96033c | 4448 | return false; |
2055d27a | 4449 | if (!RECUR (DO_BODY (t), any)) |
9c96033c | 4450 | return false; |
4451 | return true; | |
4452 | ||
4453 | case FOR_STMT: | |
2055d27a | 4454 | if (!RECUR (FOR_INIT_STMT (t), any)) |
9c96033c | 4455 | return false; |
2055d27a | 4456 | if (!RECUR (FOR_COND (t), rval)) |
9c96033c | 4457 | return false; |
2055d27a | 4458 | if (!RECUR (FOR_EXPR (t), any)) |
9c96033c | 4459 | return false; |
2055d27a | 4460 | if (!RECUR (FOR_BODY (t), any)) |
9c96033c | 4461 | return false; |
4462 | return true; | |
4463 | ||
4464 | case WHILE_STMT: | |
2055d27a | 4465 | if (!RECUR (WHILE_COND (t), rval)) |
9c96033c | 4466 | return false; |
2055d27a | 4467 | if (!RECUR (WHILE_BODY (t), any)) |
9c96033c | 4468 | return false; |
4469 | return true; | |
4470 | ||
4471 | case SWITCH_STMT: | |
2055d27a | 4472 | if (!RECUR (SWITCH_STMT_COND (t), rval)) |
9c96033c | 4473 | return false; |
748c426a | 4474 | /* FIXME we don't check SWITCH_STMT_BODY currently, because even |
4475 | unreachable labels would be checked. */ | |
9c96033c | 4476 | return true; |
4477 | ||
da7981e0 | 4478 | case STMT_EXPR: |
2055d27a | 4479 | return RECUR (STMT_EXPR_STMT (t), rval); |
da7981e0 | 4480 | |
09b42213 | 4481 | case LAMBDA_EXPR: |
4482 | case DYNAMIC_CAST_EXPR: | |
4483 | case PSEUDO_DTOR_EXPR: | |
09b42213 | 4484 | case NEW_EXPR: |
4485 | case VEC_NEW_EXPR: | |
4486 | case DELETE_EXPR: | |
4487 | case VEC_DELETE_EXPR: | |
4488 | case THROW_EXPR: | |
09b42213 | 4489 | case OMP_ATOMIC: |
4490 | case OMP_ATOMIC_READ: | |
4491 | case OMP_ATOMIC_CAPTURE_OLD: | |
4492 | case OMP_ATOMIC_CAPTURE_NEW: | |
4493 | /* GCC internal stuff. */ | |
4494 | case VA_ARG_EXPR: | |
4495 | case OBJ_TYPE_REF: | |
09b42213 | 4496 | case TRANSACTION_EXPR: |
9c96033c | 4497 | case ASM_EXPR: |
9abecca2 | 4498 | case AT_ENCODE_EXPR: |
9c96033c | 4499 | fail: |
09b42213 | 4500 | if (flags & tf_error) |
4501 | error ("expression %qE is not a constant-expression", t); | |
4502 | return false; | |
4503 | ||
4504 | case TYPEID_EXPR: | |
4505 | /* -- a typeid expression whose operand is of polymorphic | |
4506 | class type; */ | |
4507 | { | |
4508 | tree e = TREE_OPERAND (t, 0); | |
4509 | if (!TYPE_P (e) && !type_dependent_expression_p (e) | |
4510 | && TYPE_POLYMORPHIC_P (TREE_TYPE (e))) | |
4511 | { | |
4512 | if (flags & tf_error) | |
4513 | error ("typeid-expression is not a constant expression " | |
4514 | "because %qE is of polymorphic type", e); | |
4515 | return false; | |
4516 | } | |
4517 | return true; | |
4518 | } | |
4519 | ||
4520 | case MINUS_EXPR: | |
09b42213 | 4521 | want_rval = true; |
4522 | goto binary; | |
4523 | ||
4524 | case LT_EXPR: | |
4525 | case LE_EXPR: | |
4526 | case GT_EXPR: | |
4527 | case GE_EXPR: | |
4528 | case EQ_EXPR: | |
4529 | case NE_EXPR: | |
09b42213 | 4530 | want_rval = true; |
4531 | goto binary; | |
4532 | ||
9c96033c | 4533 | case PREINCREMENT_EXPR: |
4534 | case POSTINCREMENT_EXPR: | |
4535 | case PREDECREMENT_EXPR: | |
4536 | case POSTDECREMENT_EXPR: | |
4537 | if (cxx_dialect < cxx14) | |
4538 | goto fail; | |
4539 | goto unary; | |
4540 | ||
09b42213 | 4541 | case BIT_NOT_EXPR: |
4542 | /* A destructor. */ | |
4543 | if (TYPE_P (TREE_OPERAND (t, 0))) | |
4544 | return true; | |
4545 | /* else fall through. */ | |
4546 | ||
4547 | case REALPART_EXPR: | |
4548 | case IMAGPART_EXPR: | |
4549 | case CONJ_EXPR: | |
4550 | case SAVE_EXPR: | |
4551 | case FIX_TRUNC_EXPR: | |
4552 | case FLOAT_EXPR: | |
4553 | case NEGATE_EXPR: | |
4554 | case ABS_EXPR: | |
4555 | case TRUTH_NOT_EXPR: | |
4556 | case FIXED_CONVERT_EXPR: | |
4557 | case UNARY_PLUS_EXPR: | |
6fdf70f5 | 4558 | case UNARY_LEFT_FOLD_EXPR: |
4559 | case UNARY_RIGHT_FOLD_EXPR: | |
9c96033c | 4560 | unary: |
2055d27a | 4561 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 4562 | |
4563 | case CAST_EXPR: | |
4564 | case CONST_CAST_EXPR: | |
4565 | case STATIC_CAST_EXPR: | |
4566 | case REINTERPRET_CAST_EXPR: | |
4567 | case IMPLICIT_CONV_EXPR: | |
4568 | if (cxx_dialect < cxx11 | |
4569 | && !dependent_type_p (TREE_TYPE (t)) | |
4570 | && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t))) | |
4571 | /* In C++98, a conversion to non-integral type can't be part of a | |
4572 | constant expression. */ | |
4573 | { | |
4574 | if (flags & tf_error) | |
4575 | error ("cast to non-integral type %qT in a constant expression", | |
4576 | TREE_TYPE (t)); | |
4577 | return false; | |
4578 | } | |
4579 | ||
2055d27a | 4580 | return (RECUR (TREE_OPERAND (t, 0), |
4581 | TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE)); | |
09b42213 | 4582 | |
9c96033c | 4583 | case BIND_EXPR: |
2055d27a | 4584 | return RECUR (BIND_EXPR_BODY (t), want_rval); |
9c96033c | 4585 | |
4586 | case WITH_CLEANUP_EXPR: | |
4587 | case CLEANUP_POINT_EXPR: | |
4588 | case MUST_NOT_THROW_EXPR: | |
4589 | case TRY_CATCH_EXPR: | |
7f67d68c | 4590 | case TRY_BLOCK: |
9c96033c | 4591 | case EH_SPEC_BLOCK: |
4592 | case EXPR_STMT: | |
09b42213 | 4593 | case PAREN_EXPR: |
9c96033c | 4594 | case DECL_EXPR: |
09b42213 | 4595 | case NON_DEPENDENT_EXPR: |
4596 | /* For convenience. */ | |
4597 | case RETURN_EXPR: | |
2055d27a | 4598 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 4599 | |
7f67d68c | 4600 | case TRY_FINALLY_EXPR: |
4601 | return (RECUR (TREE_OPERAND (t, 0), want_rval) | |
4602 | && RECUR (TREE_OPERAND (t, 1), any)); | |
4603 | ||
09b42213 | 4604 | case SCOPE_REF: |
2055d27a | 4605 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 4606 | |
4607 | case TARGET_EXPR: | |
4608 | if (!literal_type_p (TREE_TYPE (t))) | |
4609 | { | |
4610 | if (flags & tf_error) | |
4611 | { | |
4612 | error ("temporary of non-literal type %qT in a " | |
4613 | "constant expression", TREE_TYPE (t)); | |
4614 | explain_non_literal_class (TREE_TYPE (t)); | |
4615 | } | |
4616 | return false; | |
4617 | } | |
4618 | case INIT_EXPR: | |
2055d27a | 4619 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 4620 | |
4621 | case CONSTRUCTOR: | |
4622 | { | |
4623 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
4624 | constructor_elt *ce; | |
4625 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2055d27a | 4626 | if (!RECUR (ce->value, want_rval)) |
09b42213 | 4627 | return false; |
4628 | return true; | |
4629 | } | |
4630 | ||
4631 | case TREE_LIST: | |
4632 | { | |
4633 | gcc_assert (TREE_PURPOSE (t) == NULL_TREE | |
4634 | || DECL_P (TREE_PURPOSE (t))); | |
2055d27a | 4635 | if (!RECUR (TREE_VALUE (t), want_rval)) |
09b42213 | 4636 | return false; |
4637 | if (TREE_CHAIN (t) == NULL_TREE) | |
4638 | return true; | |
2055d27a | 4639 | return RECUR (TREE_CHAIN (t), want_rval); |
09b42213 | 4640 | } |
4641 | ||
4642 | case TRUNC_DIV_EXPR: | |
4643 | case CEIL_DIV_EXPR: | |
4644 | case FLOOR_DIV_EXPR: | |
4645 | case ROUND_DIV_EXPR: | |
4646 | case TRUNC_MOD_EXPR: | |
4647 | case CEIL_MOD_EXPR: | |
4648 | case ROUND_MOD_EXPR: | |
4649 | { | |
4650 | tree denom = TREE_OPERAND (t, 1); | |
2055d27a | 4651 | if (!RECUR (denom, rval)) |
09b42213 | 4652 | return false; |
4653 | /* We can't call cxx_eval_outermost_constant_expr on an expression | |
21131a05 | 4654 | that hasn't been through instantiate_non_dependent_expr yet. */ |
09b42213 | 4655 | if (!processing_template_decl) |
4656 | denom = cxx_eval_outermost_constant_expr (denom, true); | |
4657 | if (integer_zerop (denom)) | |
4658 | { | |
4659 | if (flags & tf_error) | |
4660 | error ("division by zero is not a constant-expression"); | |
4661 | return false; | |
4662 | } | |
4663 | else | |
4664 | { | |
4665 | want_rval = true; | |
2055d27a | 4666 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 4667 | } |
4668 | } | |
4669 | ||
4670 | case COMPOUND_EXPR: | |
4671 | { | |
4672 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
4673 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
4674 | introduced by build_call_a. */ | |
4675 | tree op0 = TREE_OPERAND (t, 0); | |
4676 | tree op1 = TREE_OPERAND (t, 1); | |
4677 | STRIP_NOPS (op1); | |
4678 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
4679 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
2055d27a | 4680 | return RECUR (op0, want_rval); |
09b42213 | 4681 | else |
4682 | goto binary; | |
4683 | } | |
4684 | ||
4685 | /* If the first operand is the non-short-circuit constant, look at | |
4686 | the second operand; otherwise we only care about the first one for | |
4687 | potentiality. */ | |
4688 | case TRUTH_AND_EXPR: | |
4689 | case TRUTH_ANDIF_EXPR: | |
4690 | tmp = boolean_true_node; | |
4691 | goto truth; | |
4692 | case TRUTH_OR_EXPR: | |
4693 | case TRUTH_ORIF_EXPR: | |
4694 | tmp = boolean_false_node; | |
4695 | truth: | |
4696 | { | |
4697 | tree op = TREE_OPERAND (t, 0); | |
2055d27a | 4698 | if (!RECUR (op, rval)) |
09b42213 | 4699 | return false; |
4700 | if (!processing_template_decl) | |
4701 | op = cxx_eval_outermost_constant_expr (op, true); | |
4702 | if (tree_int_cst_equal (op, tmp)) | |
2055d27a | 4703 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 4704 | else |
4705 | return true; | |
4706 | } | |
4707 | ||
4708 | case PLUS_EXPR: | |
4709 | case MULT_EXPR: | |
4710 | case POINTER_PLUS_EXPR: | |
4711 | case RDIV_EXPR: | |
4712 | case EXACT_DIV_EXPR: | |
4713 | case MIN_EXPR: | |
4714 | case MAX_EXPR: | |
4715 | case LSHIFT_EXPR: | |
4716 | case RSHIFT_EXPR: | |
4717 | case LROTATE_EXPR: | |
4718 | case RROTATE_EXPR: | |
4719 | case BIT_IOR_EXPR: | |
4720 | case BIT_XOR_EXPR: | |
4721 | case BIT_AND_EXPR: | |
4722 | case TRUTH_XOR_EXPR: | |
4723 | case UNORDERED_EXPR: | |
4724 | case ORDERED_EXPR: | |
4725 | case UNLT_EXPR: | |
4726 | case UNLE_EXPR: | |
4727 | case UNGT_EXPR: | |
4728 | case UNGE_EXPR: | |
4729 | case UNEQ_EXPR: | |
4730 | case LTGT_EXPR: | |
4731 | case RANGE_EXPR: | |
4732 | case COMPLEX_EXPR: | |
4733 | want_rval = true; | |
4734 | /* Fall through. */ | |
4735 | case ARRAY_REF: | |
4736 | case ARRAY_RANGE_REF: | |
4737 | case MEMBER_REF: | |
4738 | case DOTSTAR_EXPR: | |
f0abe78f | 4739 | case MEM_REF: |
6fdf70f5 | 4740 | case BINARY_LEFT_FOLD_EXPR: |
4741 | case BINARY_RIGHT_FOLD_EXPR: | |
09b42213 | 4742 | binary: |
4743 | for (i = 0; i < 2; ++i) | |
2055d27a | 4744 | if (!RECUR (TREE_OPERAND (t, i), want_rval)) |
09b42213 | 4745 | return false; |
4746 | return true; | |
4747 | ||
4748 | case CILK_SYNC_STMT: | |
4749 | case CILK_SPAWN_STMT: | |
4750 | case ARRAY_NOTATION_REF: | |
4751 | return false; | |
4752 | ||
4753 | case FMA_EXPR: | |
4754 | case VEC_PERM_EXPR: | |
4755 | for (i = 0; i < 3; ++i) | |
2055d27a | 4756 | if (!RECUR (TREE_OPERAND (t, i), true)) |
09b42213 | 4757 | return false; |
4758 | return true; | |
4759 | ||
748c426a | 4760 | case IF_STMT: |
09b42213 | 4761 | case COND_EXPR: |
4762 | case VEC_COND_EXPR: | |
4763 | /* If the condition is a known constant, we know which of the legs we | |
4764 | care about; otherwise we only require that the condition and | |
4765 | either of the legs be potentially constant. */ | |
4766 | tmp = TREE_OPERAND (t, 0); | |
2055d27a | 4767 | if (!RECUR (tmp, rval)) |
09b42213 | 4768 | return false; |
4769 | if (!processing_template_decl) | |
4770 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
4771 | if (integer_zerop (tmp)) | |
2055d27a | 4772 | return RECUR (TREE_OPERAND (t, 2), want_rval); |
09b42213 | 4773 | else if (TREE_CODE (tmp) == INTEGER_CST) |
2055d27a | 4774 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 4775 | for (i = 1; i < 3; ++i) |
4776 | if (potential_constant_expression_1 (TREE_OPERAND (t, i), | |
2055d27a | 4777 | want_rval, strict, tf_none)) |
09b42213 | 4778 | return true; |
4779 | if (flags & tf_error) | |
4780 | error ("expression %qE is not a constant-expression", t); | |
4781 | return false; | |
4782 | ||
4783 | case VEC_INIT_EXPR: | |
4784 | if (VEC_INIT_EXPR_IS_CONSTEXPR (t)) | |
4785 | return true; | |
4786 | if (flags & tf_error) | |
4787 | { | |
4788 | error ("non-constant array initialization"); | |
4789 | diagnose_non_constexpr_vec_init (t); | |
4790 | } | |
4791 | return false; | |
4792 | ||
db1ae94f | 4793 | case TYPE_DECL: |
4794 | case TAG_DEFN: | |
4795 | /* We can see these in statement-expressions. */ | |
4796 | return true; | |
4797 | ||
d2c63826 | 4798 | case EMPTY_CLASS_EXPR: |
4799 | return false; | |
4800 | ||
09b42213 | 4801 | default: |
4802 | if (objc_is_property_ref (t)) | |
4803 | return false; | |
4804 | ||
4805 | sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t))); | |
4806 | gcc_unreachable(); | |
4807 | return false; | |
4808 | } | |
2055d27a | 4809 | #undef RECUR |
09b42213 | 4810 | } |
4811 | ||
4812 | /* The main entry point to the above. */ | |
4813 | ||
4814 | bool | |
4815 | potential_constant_expression (tree t) | |
4816 | { | |
2055d27a | 4817 | return potential_constant_expression_1 (t, false, true, tf_none); |
4818 | } | |
4819 | ||
4820 | bool | |
4821 | potential_static_init_expression (tree t) | |
4822 | { | |
4823 | return potential_constant_expression_1 (t, false, false, tf_none); | |
09b42213 | 4824 | } |
4825 | ||
4826 | /* As above, but require a constant rvalue. */ | |
4827 | ||
4828 | bool | |
4829 | potential_rvalue_constant_expression (tree t) | |
4830 | { | |
2055d27a | 4831 | return potential_constant_expression_1 (t, true, true, tf_none); |
09b42213 | 4832 | } |
4833 | ||
4834 | /* Like above, but complain about non-constant expressions. */ | |
4835 | ||
4836 | bool | |
4837 | require_potential_constant_expression (tree t) | |
4838 | { | |
2055d27a | 4839 | return potential_constant_expression_1 (t, false, true, tf_warning_or_error); |
09b42213 | 4840 | } |
4841 | ||
4842 | /* Cross product of the above. */ | |
4843 | ||
4844 | bool | |
4845 | require_potential_rvalue_constant_expression (tree t) | |
4846 | { | |
2055d27a | 4847 | return potential_constant_expression_1 (t, true, true, tf_warning_or_error); |
09b42213 | 4848 | } |
4849 | ||
4850 | #include "gt-cp-constexpr.h" |