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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; | |
1728 | ||
1729 | int cmp = array_index_cmp (dindex, (*elts)[middle].index); | |
1730 | if (cmp < 0) | |
1731 | end = middle; | |
1732 | else if (cmp > 0) | |
1733 | begin = middle + 1; | |
1734 | else | |
1735 | return middle; | |
1736 | } | |
1737 | ||
1738 | if (insert) | |
1739 | { | |
1740 | constructor_elt e = { dindex, NULL_TREE }; | |
1741 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), end, e); | |
1742 | return end; | |
1743 | } | |
1744 | ||
1745 | return -1; | |
1746 | } | |
1747 | ||
1748 | ||
09b42213 | 1749 | /* Subroutine of cxx_eval_constant_expression. |
1750 | Attempt to reduce a reference to an array slot. */ | |
1751 | ||
1752 | static tree | |
cf72f34d | 1753 | cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1754 | bool lval, |
09b42213 | 1755 | bool *non_constant_p, bool *overflow_p) |
1756 | { | |
1757 | tree oldary = TREE_OPERAND (t, 0); | |
cf72f34d | 1758 | tree ary = cxx_eval_constant_expression (ctx, oldary, |
1227ba74 | 1759 | lval, |
b2a43197 | 1760 | non_constant_p, overflow_p); |
09b42213 | 1761 | tree index, oldidx; |
1762 | HOST_WIDE_INT i; | |
1763 | tree elem_type; | |
1764 | unsigned len, elem_nchars = 1; | |
1765 | if (*non_constant_p) | |
1766 | return t; | |
1767 | oldidx = TREE_OPERAND (t, 1); | |
cf72f34d | 1768 | index = cxx_eval_constant_expression (ctx, oldidx, |
f83e6885 | 1769 | false, |
b2a43197 | 1770 | non_constant_p, overflow_p); |
09b42213 | 1771 | VERIFY_CONSTANT (index); |
1227ba74 | 1772 | if (lval && ary == oldary && index == oldidx) |
09b42213 | 1773 | return t; |
1227ba74 | 1774 | else if (lval) |
09b42213 | 1775 | return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL); |
1776 | elem_type = TREE_TYPE (TREE_TYPE (ary)); | |
1777 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
1778 | len = CONSTRUCTOR_NELTS (ary); | |
1779 | else if (TREE_CODE (ary) == STRING_CST) | |
1780 | { | |
1781 | elem_nchars = (TYPE_PRECISION (elem_type) | |
1782 | / TYPE_PRECISION (char_type_node)); | |
1783 | len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars; | |
1784 | } | |
1785 | else | |
1786 | { | |
1787 | /* We can't do anything with other tree codes, so use | |
1788 | VERIFY_CONSTANT to complain and fail. */ | |
1789 | VERIFY_CONSTANT (ary); | |
1790 | gcc_unreachable (); | |
1791 | } | |
aed8dc7f | 1792 | |
f6b30463 | 1793 | if (!tree_fits_shwi_p (index) |
1794 | || (i = tree_to_shwi (index)) < 0) | |
7963b19d | 1795 | { |
1796 | if (!ctx->quiet) | |
1797 | error ("negative array subscript"); | |
1798 | *non_constant_p = true; | |
1799 | return t; | |
1800 | } | |
1801 | ||
1802 | bool found; | |
1803 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
1804 | { | |
1805 | HOST_WIDE_INT ix = find_array_ctor_elt (ary, index); | |
1806 | found = (ix >= 0); | |
1807 | if (found) | |
1808 | i = ix; | |
aed8dc7f | 1809 | } |
7963b19d | 1810 | else |
1811 | found = (i < len); | |
aed8dc7f | 1812 | |
7963b19d | 1813 | if (!found) |
09b42213 | 1814 | { |
1815 | if (tree_int_cst_lt (index, array_type_nelts_top (TREE_TYPE (ary)))) | |
1816 | { | |
a02b42fe | 1817 | if (TREE_CODE (ary) == CONSTRUCTOR |
1818 | && CONSTRUCTOR_NO_IMPLICIT_ZERO (ary)) | |
1819 | { | |
1820 | /* 'ary' is part of the aggregate initializer we're currently | |
1821 | building; if there's no initializer for this element yet, | |
1822 | that's an error. */ | |
1823 | if (!ctx->quiet) | |
1824 | error ("accessing uninitialized array element"); | |
1825 | *non_constant_p = true; | |
1826 | return t; | |
1827 | } | |
1828 | ||
09b42213 | 1829 | /* If it's within the array bounds but doesn't have an explicit |
1830 | initializer, it's value-initialized. */ | |
1831 | tree val = build_value_init (elem_type, tf_warning_or_error); | |
cf72f34d | 1832 | return cxx_eval_constant_expression (ctx, val, |
1227ba74 | 1833 | lval, |
b2a43197 | 1834 | non_constant_p, overflow_p); |
09b42213 | 1835 | } |
1836 | ||
f83e6885 | 1837 | if (!ctx->quiet) |
09b42213 | 1838 | error ("array subscript out of bound"); |
1839 | *non_constant_p = true; | |
1840 | return t; | |
1841 | } | |
aed8dc7f | 1842 | |
09b42213 | 1843 | if (TREE_CODE (ary) == CONSTRUCTOR) |
1844 | return (*CONSTRUCTOR_ELTS (ary))[i].value; | |
1845 | else if (elem_nchars == 1) | |
1846 | return build_int_cst (cv_unqualified (TREE_TYPE (TREE_TYPE (ary))), | |
1847 | TREE_STRING_POINTER (ary)[i]); | |
1848 | else | |
1849 | { | |
1850 | tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (ary))); | |
1851 | return native_interpret_expr (type, (const unsigned char *) | |
1852 | TREE_STRING_POINTER (ary) | |
1853 | + i * elem_nchars, elem_nchars); | |
1854 | } | |
1855 | /* Don't VERIFY_CONSTANT here. */ | |
1856 | } | |
1857 | ||
1858 | /* Subroutine of cxx_eval_constant_expression. | |
1859 | Attempt to reduce a field access of a value of class type. */ | |
1860 | ||
1861 | static tree | |
cf72f34d | 1862 | cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1863 | bool lval, |
09b42213 | 1864 | bool *non_constant_p, bool *overflow_p) |
1865 | { | |
1866 | unsigned HOST_WIDE_INT i; | |
1867 | tree field; | |
1868 | tree value; | |
1869 | tree part = TREE_OPERAND (t, 1); | |
1870 | tree orig_whole = TREE_OPERAND (t, 0); | |
cf72f34d | 1871 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 1872 | lval, |
b2a43197 | 1873 | non_constant_p, overflow_p); |
f16ed232 | 1874 | if (TREE_CODE (whole) == PTRMEM_CST) |
1875 | whole = cplus_expand_constant (whole); | |
09b42213 | 1876 | if (whole == orig_whole) |
1877 | return t; | |
1227ba74 | 1878 | if (lval) |
09b42213 | 1879 | return fold_build3 (COMPONENT_REF, TREE_TYPE (t), |
1880 | whole, part, NULL_TREE); | |
1881 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
1882 | CONSTRUCTOR. */ | |
1883 | if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR) | |
1884 | { | |
f83e6885 | 1885 | if (!ctx->quiet) |
09b42213 | 1886 | error ("%qE is not a constant expression", orig_whole); |
1887 | *non_constant_p = true; | |
1888 | } | |
1889 | if (DECL_MUTABLE_P (part)) | |
1890 | { | |
f83e6885 | 1891 | if (!ctx->quiet) |
09b42213 | 1892 | error ("mutable %qD is not usable in a constant expression", part); |
1893 | *non_constant_p = true; | |
1894 | } | |
1895 | if (*non_constant_p) | |
1896 | return t; | |
1897 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
1898 | { | |
1899 | if (field == part) | |
9c96033c | 1900 | { |
1901 | if (value) | |
1902 | return value; | |
1903 | else | |
1904 | /* We're in the middle of initializing it. */ | |
1905 | break; | |
1906 | } | |
09b42213 | 1907 | } |
1908 | if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE | |
1909 | && CONSTRUCTOR_NELTS (whole) > 0) | |
1910 | { | |
1911 | /* DR 1188 says we don't have to deal with this. */ | |
f83e6885 | 1912 | if (!ctx->quiet) |
09b42213 | 1913 | error ("accessing %qD member instead of initialized %qD member in " |
1914 | "constant expression", part, CONSTRUCTOR_ELT (whole, 0)->index); | |
1915 | *non_constant_p = true; | |
1916 | return t; | |
1917 | } | |
1918 | ||
cf72f34d | 1919 | if (CONSTRUCTOR_NO_IMPLICIT_ZERO (whole)) |
1920 | { | |
1921 | /* 'whole' is part of the aggregate initializer we're currently | |
1922 | building; if there's no initializer for this member yet, that's an | |
1923 | error. */ | |
f83e6885 | 1924 | if (!ctx->quiet) |
cf72f34d | 1925 | error ("accessing uninitialized member %qD", part); |
1926 | *non_constant_p = true; | |
1927 | return t; | |
1928 | } | |
1929 | ||
09b42213 | 1930 | /* If there's no explicit init for this field, it's value-initialized. */ |
1931 | value = build_value_init (TREE_TYPE (t), tf_warning_or_error); | |
cf72f34d | 1932 | return cxx_eval_constant_expression (ctx, value, |
1227ba74 | 1933 | lval, |
b2a43197 | 1934 | non_constant_p, overflow_p); |
09b42213 | 1935 | } |
1936 | ||
1937 | /* Subroutine of cxx_eval_constant_expression. | |
1938 | Attempt to reduce a field access of a value of class type that is | |
1939 | expressed as a BIT_FIELD_REF. */ | |
1940 | ||
1941 | static tree | |
cf72f34d | 1942 | cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1943 | bool lval, |
09b42213 | 1944 | bool *non_constant_p, bool *overflow_p) |
1945 | { | |
1946 | tree orig_whole = TREE_OPERAND (t, 0); | |
1947 | tree retval, fldval, utype, mask; | |
1948 | bool fld_seen = false; | |
1949 | HOST_WIDE_INT istart, isize; | |
cf72f34d | 1950 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 1951 | lval, |
b2a43197 | 1952 | non_constant_p, overflow_p); |
09b42213 | 1953 | tree start, field, value; |
1954 | unsigned HOST_WIDE_INT i; | |
1955 | ||
1956 | if (whole == orig_whole) | |
1957 | return t; | |
1958 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
1959 | CONSTRUCTOR. */ | |
1960 | if (!*non_constant_p | |
1961 | && TREE_CODE (whole) != VECTOR_CST | |
1962 | && TREE_CODE (whole) != CONSTRUCTOR) | |
1963 | { | |
f83e6885 | 1964 | if (!ctx->quiet) |
09b42213 | 1965 | error ("%qE is not a constant expression", orig_whole); |
1966 | *non_constant_p = true; | |
1967 | } | |
1968 | if (*non_constant_p) | |
1969 | return t; | |
1970 | ||
1971 | if (TREE_CODE (whole) == VECTOR_CST) | |
1972 | return fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole, | |
1973 | TREE_OPERAND (t, 1), TREE_OPERAND (t, 2)); | |
1974 | ||
1975 | start = TREE_OPERAND (t, 2); | |
1976 | istart = tree_to_shwi (start); | |
1977 | isize = tree_to_shwi (TREE_OPERAND (t, 1)); | |
1978 | utype = TREE_TYPE (t); | |
1979 | if (!TYPE_UNSIGNED (utype)) | |
1980 | utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1); | |
1981 | retval = build_int_cst (utype, 0); | |
1982 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
1983 | { | |
1984 | tree bitpos = bit_position (field); | |
1985 | if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1)) | |
1986 | return value; | |
1987 | if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE | |
1988 | && TREE_CODE (value) == INTEGER_CST | |
1989 | && tree_fits_shwi_p (bitpos) | |
1990 | && tree_fits_shwi_p (DECL_SIZE (field))) | |
1991 | { | |
1992 | HOST_WIDE_INT bit = tree_to_shwi (bitpos); | |
1993 | HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field)); | |
1994 | HOST_WIDE_INT shift; | |
1995 | if (bit >= istart && bit + sz <= istart + isize) | |
1996 | { | |
1997 | fldval = fold_convert (utype, value); | |
1998 | mask = build_int_cst_type (utype, -1); | |
1999 | mask = fold_build2 (LSHIFT_EXPR, utype, mask, | |
2000 | size_int (TYPE_PRECISION (utype) - sz)); | |
2001 | mask = fold_build2 (RSHIFT_EXPR, utype, mask, | |
2002 | size_int (TYPE_PRECISION (utype) - sz)); | |
2003 | fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask); | |
2004 | shift = bit - istart; | |
2005 | if (BYTES_BIG_ENDIAN) | |
2006 | shift = TYPE_PRECISION (utype) - shift - sz; | |
2007 | fldval = fold_build2 (LSHIFT_EXPR, utype, fldval, | |
2008 | size_int (shift)); | |
2009 | retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval); | |
2010 | fld_seen = true; | |
2011 | } | |
2012 | } | |
2013 | } | |
2014 | if (fld_seen) | |
2015 | return fold_convert (TREE_TYPE (t), retval); | |
2016 | gcc_unreachable (); | |
2017 | return error_mark_node; | |
2018 | } | |
2019 | ||
2020 | /* Subroutine of cxx_eval_constant_expression. | |
2021 | Evaluate a short-circuited logical expression T in the context | |
2022 | of a given constexpr CALL. BAILOUT_VALUE is the value for | |
2023 | early return. CONTINUE_VALUE is used here purely for | |
2024 | sanity check purposes. */ | |
2025 | ||
2026 | static tree | |
cf72f34d | 2027 | cxx_eval_logical_expression (const constexpr_ctx *ctx, tree t, |
09b42213 | 2028 | tree bailout_value, tree continue_value, |
1227ba74 | 2029 | bool lval, |
09b42213 | 2030 | bool *non_constant_p, bool *overflow_p) |
2031 | { | |
2032 | tree r; | |
cf72f34d | 2033 | tree lhs = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 2034 | lval, |
b2a43197 | 2035 | non_constant_p, overflow_p); |
09b42213 | 2036 | VERIFY_CONSTANT (lhs); |
2037 | if (tree_int_cst_equal (lhs, bailout_value)) | |
2038 | return lhs; | |
2039 | gcc_assert (tree_int_cst_equal (lhs, continue_value)); | |
cf72f34d | 2040 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2041 | lval, non_constant_p, |
b2a43197 | 2042 | overflow_p); |
09b42213 | 2043 | VERIFY_CONSTANT (r); |
2044 | return r; | |
2045 | } | |
2046 | ||
2047 | /* REF is a COMPONENT_REF designating a particular field. V is a vector of | |
2048 | CONSTRUCTOR elements to initialize (part of) an object containing that | |
2049 | field. Return a pointer to the constructor_elt corresponding to the | |
2050 | initialization of the field. */ | |
2051 | ||
2052 | static constructor_elt * | |
2053 | base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref) | |
2054 | { | |
2055 | tree aggr = TREE_OPERAND (ref, 0); | |
2056 | tree field = TREE_OPERAND (ref, 1); | |
2057 | HOST_WIDE_INT i; | |
2058 | constructor_elt *ce; | |
2059 | ||
2060 | gcc_assert (TREE_CODE (ref) == COMPONENT_REF); | |
2061 | ||
2062 | if (TREE_CODE (aggr) == COMPONENT_REF) | |
2063 | { | |
2064 | constructor_elt *base_ce | |
2065 | = base_field_constructor_elt (v, aggr); | |
2066 | v = CONSTRUCTOR_ELTS (base_ce->value); | |
2067 | } | |
2068 | ||
2069 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2070 | if (ce->index == field) | |
2071 | return ce; | |
2072 | ||
2073 | gcc_unreachable (); | |
2074 | return NULL; | |
2075 | } | |
2076 | ||
cf72f34d | 2077 | /* Some of the expressions fed to the constexpr mechanism are calls to |
2078 | constructors, which have type void. In that case, return the type being | |
2079 | initialized by the constructor. */ | |
2080 | ||
2081 | static tree | |
2082 | initialized_type (tree t) | |
2083 | { | |
2084 | if (TYPE_P (t)) | |
2085 | return t; | |
2086 | tree type = cv_unqualified (TREE_TYPE (t)); | |
2087 | if (TREE_CODE (t) == CALL_EXPR || TREE_CODE (t) == AGGR_INIT_EXPR) | |
2088 | { | |
2089 | /* A constructor call has void type, so we need to look deeper. */ | |
2090 | tree fn = get_function_named_in_call (t); | |
2091 | if (fn && TREE_CODE (fn) == FUNCTION_DECL | |
2092 | && DECL_CXX_CONSTRUCTOR_P (fn)) | |
2093 | type = DECL_CONTEXT (fn); | |
2094 | } | |
2095 | return type; | |
2096 | } | |
2097 | ||
2098 | /* We're about to initialize element INDEX of an array or class from VALUE. | |
2099 | Set up NEW_CTX appropriately by adjusting .object to refer to the | |
2100 | subobject and creating a new CONSTRUCTOR if the element is itself | |
2101 | a class or array. */ | |
2102 | ||
2103 | static void | |
2104 | init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, | |
2105 | tree index, tree &value) | |
2106 | { | |
2107 | new_ctx = *ctx; | |
2108 | ||
2109 | if (index && TREE_CODE (index) != INTEGER_CST | |
2110 | && TREE_CODE (index) != FIELD_DECL) | |
2111 | /* This won't have an element in the new CONSTRUCTOR. */ | |
2112 | return; | |
2113 | ||
2114 | tree type = initialized_type (value); | |
2115 | if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) | |
2116 | /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ | |
2117 | return; | |
2118 | ||
2119 | /* The sub-aggregate initializer might contain a placeholder; | |
2120 | update object to refer to the subobject and ctor to refer to | |
2121 | the (newly created) sub-initializer. */ | |
2122 | if (ctx->object) | |
2123 | new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); | |
2124 | tree elt = build_constructor (type, NULL); | |
2125 | CONSTRUCTOR_NO_IMPLICIT_ZERO (elt) = true; | |
2126 | new_ctx.ctor = elt; | |
2127 | ||
2128 | if (TREE_CODE (value) == TARGET_EXPR) | |
2129 | /* Avoid creating another CONSTRUCTOR when we expand the TARGET_EXPR. */ | |
2130 | value = TARGET_EXPR_INITIAL (value); | |
2131 | } | |
2132 | ||
2133 | /* We're about to process an initializer for a class or array TYPE. Make | |
2134 | sure that CTX is set up appropriately. */ | |
2135 | ||
2136 | static void | |
2137 | verify_ctor_sanity (const constexpr_ctx *ctx, tree type) | |
2138 | { | |
2139 | /* We don't bother building a ctor for an empty base subobject. */ | |
2140 | if (is_empty_class (type)) | |
2141 | return; | |
2142 | ||
2143 | /* We're in the middle of an initializer that might involve placeholders; | |
2144 | our caller should have created a CONSTRUCTOR for us to put the | |
2145 | initializer into. We will either return that constructor or T. */ | |
2146 | gcc_assert (ctx->ctor); | |
2147 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2148 | (type, TREE_TYPE (ctx->ctor))); | |
2149 | gcc_assert (CONSTRUCTOR_NELTS (ctx->ctor) == 0); | |
2150 | if (ctx->object) | |
2151 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2152 | (type, TREE_TYPE (ctx->object))); | |
2153 | gcc_assert (!ctx->object || !DECL_P (ctx->object) | |
2154 | || *(ctx->values->get (ctx->object)) == ctx->ctor); | |
2155 | } | |
2156 | ||
09b42213 | 2157 | /* Subroutine of cxx_eval_constant_expression. |
2158 | The expression tree T denotes a C-style array or a C-style | |
2159 | aggregate. Reduce it to a constant expression. */ | |
2160 | ||
2161 | static tree | |
cf72f34d | 2162 | cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2163 | bool lval, |
09b42213 | 2164 | bool *non_constant_p, bool *overflow_p) |
2165 | { | |
2166 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
09b42213 | 2167 | bool changed = false; |
2168 | gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t)); | |
cf72f34d | 2169 | |
2170 | verify_ctor_sanity (ctx, TREE_TYPE (t)); | |
2171 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
2172 | vec_alloc (*p, vec_safe_length (v)); | |
2173 | ||
2174 | unsigned i; tree index, value; | |
2175 | FOR_EACH_CONSTRUCTOR_ELT (v, i, index, value) | |
09b42213 | 2176 | { |
cf72f34d | 2177 | constexpr_ctx new_ctx; |
2178 | init_subob_ctx (ctx, new_ctx, index, value); | |
2179 | if (new_ctx.ctor != ctx->ctor) | |
2180 | /* If we built a new CONSTRUCTOR, attach it now so that other | |
2181 | initializers can refer to it. */ | |
2182 | CONSTRUCTOR_APPEND_ELT (*p, index, new_ctx.ctor); | |
2183 | tree elt = cxx_eval_constant_expression (&new_ctx, value, | |
1227ba74 | 2184 | lval, |
b2a43197 | 2185 | non_constant_p, overflow_p); |
09b42213 | 2186 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 2187 | if (ctx->quiet && *non_constant_p) |
cf72f34d | 2188 | break; |
2189 | if (elt != value) | |
09b42213 | 2190 | changed = true; |
cf72f34d | 2191 | if (index && TREE_CODE (index) == COMPONENT_REF) |
09b42213 | 2192 | { |
2193 | /* This is an initialization of a vfield inside a base | |
2194 | subaggregate that we already initialized; push this | |
2195 | initialization into the previous initialization. */ | |
cf72f34d | 2196 | constructor_elt *inner = base_field_constructor_elt (*p, index); |
09b42213 | 2197 | inner->value = elt; |
cf72f34d | 2198 | changed = true; |
09b42213 | 2199 | } |
cf72f34d | 2200 | else if (index |
2201 | && (TREE_CODE (index) == NOP_EXPR | |
2202 | || TREE_CODE (index) == POINTER_PLUS_EXPR)) | |
09b42213 | 2203 | { |
2204 | /* This is an initializer for an empty base; now that we've | |
2205 | checked that it's constant, we can ignore it. */ | |
cf72f34d | 2206 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (index)))); |
2207 | changed = true; | |
2208 | } | |
2209 | else if (new_ctx.ctor != ctx->ctor) | |
2210 | { | |
2211 | /* We appended this element above; update the value. */ | |
2212 | gcc_assert ((*p)->last().index == index); | |
2213 | (*p)->last().value = elt; | |
09b42213 | 2214 | } |
2215 | else | |
cf72f34d | 2216 | CONSTRUCTOR_APPEND_ELT (*p, index, elt); |
09b42213 | 2217 | } |
2218 | if (*non_constant_p || !changed) | |
cf72f34d | 2219 | return t; |
2220 | t = ctx->ctor; | |
2221 | /* We're done building this CONSTRUCTOR, so now we can interpret an | |
2222 | element without an explicit initializer as value-initialized. */ | |
2223 | CONSTRUCTOR_NO_IMPLICIT_ZERO (t) = false; | |
76249021 | 2224 | if (VECTOR_TYPE_P (TREE_TYPE (t))) |
09b42213 | 2225 | t = fold (t); |
2226 | return t; | |
2227 | } | |
2228 | ||
2229 | /* Subroutine of cxx_eval_constant_expression. | |
2230 | The expression tree T is a VEC_INIT_EXPR which denotes the desired | |
2231 | initialization of a non-static data member of array type. Reduce it to a | |
2232 | CONSTRUCTOR. | |
2233 | ||
2234 | Note that apart from value-initialization (when VALUE_INIT is true), | |
2235 | this is only intended to support value-initialization and the | |
2236 | initializations done by defaulted constructors for classes with | |
2237 | non-static data members of array type. In this case, VEC_INIT_EXPR_INIT | |
2238 | will either be NULL_TREE for the default constructor, or a COMPONENT_REF | |
2239 | for the copy/move constructor. */ | |
2240 | ||
2241 | static tree | |
cf72f34d | 2242 | cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, |
1227ba74 | 2243 | bool value_init, bool lval, |
09b42213 | 2244 | bool *non_constant_p, bool *overflow_p) |
2245 | { | |
2246 | tree elttype = TREE_TYPE (atype); | |
3e520b97 | 2247 | unsigned HOST_WIDE_INT max = tree_to_uhwi (array_type_nelts_top (atype)); |
cf72f34d | 2248 | verify_ctor_sanity (ctx, atype); |
2249 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
2250 | vec_alloc (*p, max + 1); | |
09b42213 | 2251 | bool pre_init = false; |
3e520b97 | 2252 | unsigned HOST_WIDE_INT i; |
09b42213 | 2253 | |
2254 | /* For the default constructor, build up a call to the default | |
2255 | constructor of the element type. We only need to handle class types | |
2256 | here, as for a constructor to be constexpr, all members must be | |
2257 | initialized, which for a defaulted default constructor means they must | |
2258 | be of a class type with a constexpr default constructor. */ | |
2259 | if (TREE_CODE (elttype) == ARRAY_TYPE) | |
2260 | /* We only do this at the lowest level. */; | |
2261 | else if (value_init) | |
2262 | { | |
2263 | init = build_value_init (elttype, tf_warning_or_error); | |
09b42213 | 2264 | pre_init = true; |
2265 | } | |
2266 | else if (!init) | |
2267 | { | |
2268 | vec<tree, va_gc> *argvec = make_tree_vector (); | |
2269 | init = build_special_member_call (NULL_TREE, complete_ctor_identifier, | |
2270 | &argvec, elttype, LOOKUP_NORMAL, | |
2271 | tf_warning_or_error); | |
2272 | release_tree_vector (argvec); | |
9c96033c | 2273 | init = build_aggr_init_expr (TREE_TYPE (init), init); |
09b42213 | 2274 | pre_init = true; |
2275 | } | |
2276 | ||
3e520b97 | 2277 | for (i = 0; i < max; ++i) |
09b42213 | 2278 | { |
2279 | tree idx = build_int_cst (size_type_node, i); | |
2280 | tree eltinit; | |
cf72f34d | 2281 | constexpr_ctx new_ctx; |
2282 | init_subob_ctx (ctx, new_ctx, idx, pre_init ? init : elttype); | |
2283 | if (new_ctx.ctor != ctx->ctor) | |
2284 | CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor); | |
09b42213 | 2285 | if (TREE_CODE (elttype) == ARRAY_TYPE) |
2286 | { | |
2287 | /* A multidimensional array; recurse. */ | |
2288 | if (value_init || init == NULL_TREE) | |
2289 | eltinit = NULL_TREE; | |
2290 | else | |
2291 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2292 | tf_warning_or_error); | |
cf72f34d | 2293 | eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, value_init, |
1227ba74 | 2294 | lval, |
09b42213 | 2295 | non_constant_p, overflow_p); |
2296 | } | |
2297 | else if (pre_init) | |
2298 | { | |
2299 | /* Initializing an element using value or default initialization | |
2300 | we just pre-built above. */ | |
cf72f34d | 2301 | eltinit = (cxx_eval_constant_expression |
f83e6885 | 2302 | (&new_ctx, init, |
1227ba74 | 2303 | lval, non_constant_p, overflow_p)); |
09b42213 | 2304 | } |
2305 | else | |
2306 | { | |
2307 | /* Copying an element. */ | |
2308 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2309 | (atype, TREE_TYPE (init))); | |
2310 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2311 | tf_warning_or_error); | |
2312 | if (!real_lvalue_p (init)) | |
2313 | eltinit = move (eltinit); | |
2314 | eltinit = force_rvalue (eltinit, tf_warning_or_error); | |
cf72f34d | 2315 | eltinit = (cxx_eval_constant_expression |
1227ba74 | 2316 | (&new_ctx, eltinit, lval, |
b2a43197 | 2317 | non_constant_p, overflow_p)); |
09b42213 | 2318 | } |
f83e6885 | 2319 | if (*non_constant_p && !ctx->quiet) |
cf72f34d | 2320 | break; |
2321 | if (new_ctx.ctor != ctx->ctor) | |
2322 | { | |
2323 | /* We appended this element above; update the value. */ | |
2324 | gcc_assert ((*p)->last().index == idx); | |
2325 | (*p)->last().value = eltinit; | |
2326 | } | |
2327 | else | |
2328 | CONSTRUCTOR_APPEND_ELT (*p, idx, eltinit); | |
09b42213 | 2329 | } |
2330 | ||
2331 | if (!*non_constant_p) | |
2332 | { | |
cf72f34d | 2333 | init = ctx->ctor; |
2334 | CONSTRUCTOR_NO_IMPLICIT_ZERO (init) = false; | |
09b42213 | 2335 | } |
09b42213 | 2336 | return init; |
2337 | } | |
2338 | ||
2339 | static tree | |
cf72f34d | 2340 | cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2341 | bool lval, |
09b42213 | 2342 | bool *non_constant_p, bool *overflow_p) |
2343 | { | |
2344 | tree atype = TREE_TYPE (t); | |
2345 | tree init = VEC_INIT_EXPR_INIT (t); | |
cf72f34d | 2346 | tree r = cxx_eval_vec_init_1 (ctx, atype, init, |
09b42213 | 2347 | VEC_INIT_EXPR_VALUE_INIT (t), |
1227ba74 | 2348 | lval, non_constant_p, overflow_p); |
09b42213 | 2349 | if (*non_constant_p) |
2350 | return t; | |
2351 | else | |
2352 | return r; | |
2353 | } | |
2354 | ||
2355 | /* A less strict version of fold_indirect_ref_1, which requires cv-quals to | |
2356 | match. We want to be less strict for simple *& folding; if we have a | |
2357 | non-const temporary that we access through a const pointer, that should | |
2358 | work. We handle this here rather than change fold_indirect_ref_1 | |
2359 | because we're dealing with things like ADDR_EXPR of INTEGER_CST which | |
2360 | don't really make sense outside of constant expression evaluation. Also | |
2361 | we want to allow folding to COMPONENT_REF, which could cause trouble | |
2362 | with TBAA in fold_indirect_ref_1. | |
2363 | ||
2364 | Try to keep this function synced with fold_indirect_ref_1. */ | |
2365 | ||
2366 | static tree | |
2367 | cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) | |
2368 | { | |
2369 | tree sub, subtype; | |
2370 | ||
2371 | sub = op0; | |
2372 | STRIP_NOPS (sub); | |
2373 | subtype = TREE_TYPE (sub); | |
2374 | if (!POINTER_TYPE_P (subtype)) | |
2375 | return NULL_TREE; | |
2376 | ||
2377 | if (TREE_CODE (sub) == ADDR_EXPR) | |
2378 | { | |
2379 | tree op = TREE_OPERAND (sub, 0); | |
2380 | tree optype = TREE_TYPE (op); | |
2381 | ||
2382 | /* *&CONST_DECL -> to the value of the const decl. */ | |
2383 | if (TREE_CODE (op) == CONST_DECL) | |
2384 | return DECL_INITIAL (op); | |
2385 | /* *&p => p; make sure to handle *&"str"[cst] here. */ | |
c4118b0c | 2386 | if (same_type_ignoring_top_level_qualifiers_p (optype, type) |
2387 | /* Also handle the case where the desired type is an array of unknown | |
2388 | bounds because the variable has had its bounds deduced since the | |
2389 | ADDR_EXPR was created. */ | |
2390 | || (TREE_CODE (type) == ARRAY_TYPE | |
2391 | && TREE_CODE (optype) == ARRAY_TYPE | |
2392 | && TYPE_DOMAIN (type) == NULL_TREE | |
2393 | && same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (optype), | |
2394 | TREE_TYPE (type)))) | |
09b42213 | 2395 | { |
2396 | tree fop = fold_read_from_constant_string (op); | |
2397 | if (fop) | |
2398 | return fop; | |
2399 | else | |
2400 | return op; | |
2401 | } | |
2402 | /* *(foo *)&fooarray => fooarray[0] */ | |
2403 | else if (TREE_CODE (optype) == ARRAY_TYPE | |
2404 | && (same_type_ignoring_top_level_qualifiers_p | |
2405 | (type, TREE_TYPE (optype)))) | |
2406 | { | |
2407 | tree type_domain = TYPE_DOMAIN (optype); | |
2408 | tree min_val = size_zero_node; | |
2409 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
2410 | min_val = TYPE_MIN_VALUE (type_domain); | |
2411 | return build4_loc (loc, ARRAY_REF, type, op, min_val, | |
2412 | NULL_TREE, NULL_TREE); | |
2413 | } | |
2414 | /* *(foo *)&complexfoo => __real__ complexfoo */ | |
2415 | else if (TREE_CODE (optype) == COMPLEX_TYPE | |
2416 | && (same_type_ignoring_top_level_qualifiers_p | |
2417 | (type, TREE_TYPE (optype)))) | |
2418 | return fold_build1_loc (loc, REALPART_EXPR, type, op); | |
2419 | /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 2420 | else if (VECTOR_TYPE_P (optype) |
09b42213 | 2421 | && (same_type_ignoring_top_level_qualifiers_p |
2422 | (type, TREE_TYPE (optype)))) | |
2423 | { | |
2424 | tree part_width = TYPE_SIZE (type); | |
2425 | tree index = bitsize_int (0); | |
2426 | return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, index); | |
2427 | } | |
2428 | /* Also handle conversion to an empty base class, which | |
2429 | is represented with a NOP_EXPR. */ | |
2430 | else if (is_empty_class (type) | |
2431 | && CLASS_TYPE_P (optype) | |
2432 | && DERIVED_FROM_P (type, optype)) | |
2433 | { | |
2434 | *empty_base = true; | |
2435 | return op; | |
2436 | } | |
2437 | /* *(foo *)&struct_with_foo_field => COMPONENT_REF */ | |
2438 | else if (RECORD_OR_UNION_TYPE_P (optype)) | |
2439 | { | |
2440 | tree field = TYPE_FIELDS (optype); | |
2441 | for (; field; field = DECL_CHAIN (field)) | |
2442 | if (TREE_CODE (field) == FIELD_DECL | |
2443 | && integer_zerop (byte_position (field)) | |
2444 | && (same_type_ignoring_top_level_qualifiers_p | |
2445 | (TREE_TYPE (field), type))) | |
2446 | { | |
2447 | return fold_build3 (COMPONENT_REF, type, op, field, NULL_TREE); | |
2448 | break; | |
2449 | } | |
2450 | } | |
2451 | } | |
2452 | else if (TREE_CODE (sub) == POINTER_PLUS_EXPR | |
2453 | && TREE_CODE (TREE_OPERAND (sub, 1)) == INTEGER_CST) | |
2454 | { | |
2455 | tree op00 = TREE_OPERAND (sub, 0); | |
2456 | tree op01 = TREE_OPERAND (sub, 1); | |
2457 | ||
2458 | STRIP_NOPS (op00); | |
2459 | if (TREE_CODE (op00) == ADDR_EXPR) | |
2460 | { | |
2461 | tree op00type; | |
2462 | op00 = TREE_OPERAND (op00, 0); | |
2463 | op00type = TREE_TYPE (op00); | |
2464 | ||
2465 | /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 2466 | if (VECTOR_TYPE_P (op00type) |
09b42213 | 2467 | && (same_type_ignoring_top_level_qualifiers_p |
2468 | (type, TREE_TYPE (op00type)))) | |
2469 | { | |
2470 | HOST_WIDE_INT offset = tree_to_shwi (op01); | |
2471 | tree part_width = TYPE_SIZE (type); | |
2472 | unsigned HOST_WIDE_INT part_widthi = tree_to_shwi (part_width)/BITS_PER_UNIT; | |
2473 | unsigned HOST_WIDE_INT indexi = offset * BITS_PER_UNIT; | |
2474 | tree index = bitsize_int (indexi); | |
2475 | ||
2476 | if (offset / part_widthi < TYPE_VECTOR_SUBPARTS (op00type)) | |
2477 | return fold_build3_loc (loc, | |
2478 | BIT_FIELD_REF, type, op00, | |
2479 | part_width, index); | |
2480 | ||
2481 | } | |
2482 | /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ | |
2483 | else if (TREE_CODE (op00type) == COMPLEX_TYPE | |
2484 | && (same_type_ignoring_top_level_qualifiers_p | |
2485 | (type, TREE_TYPE (op00type)))) | |
2486 | { | |
2487 | tree size = TYPE_SIZE_UNIT (type); | |
2488 | if (tree_int_cst_equal (size, op01)) | |
2489 | return fold_build1_loc (loc, IMAGPART_EXPR, type, op00); | |
2490 | } | |
2491 | /* ((foo *)&fooarray)[1] => fooarray[1] */ | |
2492 | else if (TREE_CODE (op00type) == ARRAY_TYPE | |
2493 | && (same_type_ignoring_top_level_qualifiers_p | |
2494 | (type, TREE_TYPE (op00type)))) | |
2495 | { | |
2496 | tree type_domain = TYPE_DOMAIN (op00type); | |
2497 | tree min_val = size_zero_node; | |
2498 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
2499 | min_val = TYPE_MIN_VALUE (type_domain); | |
2500 | op01 = size_binop_loc (loc, EXACT_DIV_EXPR, op01, | |
2501 | TYPE_SIZE_UNIT (type)); | |
2502 | op01 = size_binop_loc (loc, PLUS_EXPR, op01, min_val); | |
2503 | return build4_loc (loc, ARRAY_REF, type, op00, op01, | |
2504 | NULL_TREE, NULL_TREE); | |
2505 | } | |
2506 | /* Also handle conversion to an empty base class, which | |
2507 | is represented with a NOP_EXPR. */ | |
2508 | else if (is_empty_class (type) | |
2509 | && CLASS_TYPE_P (op00type) | |
2510 | && DERIVED_FROM_P (type, op00type)) | |
2511 | { | |
2512 | *empty_base = true; | |
2513 | return op00; | |
2514 | } | |
2515 | /* ((foo *)&struct_with_foo_field)[1] => COMPONENT_REF */ | |
2516 | else if (RECORD_OR_UNION_TYPE_P (op00type)) | |
2517 | { | |
2518 | tree field = TYPE_FIELDS (op00type); | |
2519 | for (; field; field = DECL_CHAIN (field)) | |
2520 | if (TREE_CODE (field) == FIELD_DECL | |
2521 | && tree_int_cst_equal (byte_position (field), op01) | |
2522 | && (same_type_ignoring_top_level_qualifiers_p | |
2523 | (TREE_TYPE (field), type))) | |
2524 | { | |
2525 | return fold_build3 (COMPONENT_REF, type, op00, | |
01b280db | 2526 | field, NULL_TREE); |
09b42213 | 2527 | break; |
2528 | } | |
2529 | } | |
2530 | } | |
2531 | } | |
2532 | /* *(foo *)fooarrptr => (*fooarrptr)[0] */ | |
2533 | else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE | |
2534 | && (same_type_ignoring_top_level_qualifiers_p | |
2535 | (type, TREE_TYPE (TREE_TYPE (subtype))))) | |
2536 | { | |
2537 | tree type_domain; | |
2538 | tree min_val = size_zero_node; | |
2539 | tree newsub = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL); | |
2540 | if (newsub) | |
2541 | sub = newsub; | |
2542 | else | |
2543 | sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub); | |
2544 | type_domain = TYPE_DOMAIN (TREE_TYPE (sub)); | |
2545 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
2546 | min_val = TYPE_MIN_VALUE (type_domain); | |
2547 | return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE, | |
2548 | NULL_TREE); | |
2549 | } | |
2550 | ||
2551 | return NULL_TREE; | |
2552 | } | |
2553 | ||
2554 | static tree | |
cf72f34d | 2555 | cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2556 | bool lval, |
09b42213 | 2557 | bool *non_constant_p, bool *overflow_p) |
2558 | { | |
2559 | tree orig_op0 = TREE_OPERAND (t, 0); | |
09b42213 | 2560 | bool empty_base = false; |
09b42213 | 2561 | |
d2c63826 | 2562 | /* We can handle a MEM_REF like an INDIRECT_REF, if MEM_REF's second |
2563 | operand is an integer-zero. Otherwise reject the MEM_REF for now. */ | |
2564 | ||
2565 | if (TREE_CODE (t) == MEM_REF | |
2566 | && (!TREE_OPERAND (t, 1) || !integer_zerop (TREE_OPERAND (t, 1)))) | |
2567 | { | |
2568 | gcc_assert (ctx->quiet); | |
2569 | *non_constant_p = true; | |
2570 | return t; | |
2571 | } | |
2572 | ||
7e0f3388 | 2573 | /* First try to simplify it directly. */ |
2574 | tree r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), orig_op0, | |
2575 | &empty_base); | |
2576 | if (!r) | |
09b42213 | 2577 | { |
7e0f3388 | 2578 | /* If that didn't work, evaluate the operand first. */ |
2579 | tree op0 = cxx_eval_constant_expression (ctx, orig_op0, | |
2580 | /*lval*/false, non_constant_p, | |
2581 | overflow_p); | |
2582 | /* Don't VERIFY_CONSTANT here. */ | |
2583 | if (*non_constant_p) | |
2584 | return t; | |
2585 | ||
2586 | r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), op0, | |
2587 | &empty_base); | |
2588 | if (r == NULL_TREE) | |
09b42213 | 2589 | { |
2590 | /* We couldn't fold to a constant value. Make sure it's not | |
2591 | something we should have been able to fold. */ | |
7e0f3388 | 2592 | tree sub = op0; |
2593 | STRIP_NOPS (sub); | |
2594 | if (TREE_CODE (sub) == ADDR_EXPR) | |
2595 | { | |
2596 | gcc_assert (!same_type_ignoring_top_level_qualifiers_p | |
2597 | (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t))); | |
2598 | /* DR 1188 says we don't have to deal with this. */ | |
2599 | if (!ctx->quiet) | |
2600 | error ("accessing value of %qE through a %qT glvalue in a " | |
2601 | "constant expression", build_fold_indirect_ref (sub), | |
2602 | TREE_TYPE (t)); | |
2603 | *non_constant_p = true; | |
2604 | return t; | |
2605 | } | |
2606 | ||
2607 | if (lval && op0 != orig_op0) | |
2608 | return build1 (INDIRECT_REF, TREE_TYPE (t), op0); | |
2609 | if (!lval) | |
2610 | VERIFY_CONSTANT (t); | |
09b42213 | 2611 | return t; |
2612 | } | |
2613 | } | |
2614 | ||
7e0f3388 | 2615 | r = cxx_eval_constant_expression (ctx, r, |
2616 | lval, non_constant_p, overflow_p); | |
2617 | if (*non_constant_p) | |
2618 | return t; | |
2619 | ||
09b42213 | 2620 | /* If we're pulling out the value of an empty base, make sure |
2621 | that the whole object is constant and then return an empty | |
2622 | CONSTRUCTOR. */ | |
1227ba74 | 2623 | if (empty_base && !lval) |
09b42213 | 2624 | { |
2625 | VERIFY_CONSTANT (r); | |
2626 | r = build_constructor (TREE_TYPE (t), NULL); | |
2627 | TREE_CONSTANT (r) = true; | |
2628 | } | |
2629 | ||
09b42213 | 2630 | return r; |
2631 | } | |
2632 | ||
2633 | /* Complain about R, a VAR_DECL, not being usable in a constant expression. | |
2634 | Shared between potential_constant_expression and | |
2635 | cxx_eval_constant_expression. */ | |
2636 | ||
2637 | static void | |
2638 | non_const_var_error (tree r) | |
2639 | { | |
2640 | tree type = TREE_TYPE (r); | |
2641 | error ("the value of %qD is not usable in a constant " | |
2642 | "expression", r); | |
2643 | /* Avoid error cascade. */ | |
2644 | if (DECL_INITIAL (r) == error_mark_node) | |
2645 | return; | |
2646 | if (DECL_DECLARED_CONSTEXPR_P (r)) | |
2647 | inform (DECL_SOURCE_LOCATION (r), | |
2648 | "%qD used in its own initializer", r); | |
2649 | else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) | |
2650 | { | |
2651 | if (!CP_TYPE_CONST_P (type)) | |
2652 | inform (DECL_SOURCE_LOCATION (r), | |
2653 | "%q#D is not const", r); | |
2654 | else if (CP_TYPE_VOLATILE_P (type)) | |
2655 | inform (DECL_SOURCE_LOCATION (r), | |
2656 | "%q#D is volatile", r); | |
2657 | else if (!DECL_INITIAL (r) | |
2658 | || !TREE_CONSTANT (DECL_INITIAL (r))) | |
2659 | inform (DECL_SOURCE_LOCATION (r), | |
2660 | "%qD was not initialized with a constant " | |
2661 | "expression", r); | |
2662 | else | |
2663 | gcc_unreachable (); | |
2664 | } | |
2665 | else | |
2666 | { | |
2667 | if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r)) | |
2668 | inform (DECL_SOURCE_LOCATION (r), | |
2669 | "%qD was not declared %<constexpr%>", r); | |
2670 | else | |
2671 | inform (DECL_SOURCE_LOCATION (r), | |
2672 | "%qD does not have integral or enumeration type", | |
2673 | r); | |
2674 | } | |
2675 | } | |
2676 | ||
2677 | /* Subroutine of cxx_eval_constant_expression. | |
2678 | Like cxx_eval_unary_expression, except for trinary expressions. */ | |
2679 | ||
2680 | static tree | |
cf72f34d | 2681 | cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2682 | bool lval, |
09b42213 | 2683 | bool *non_constant_p, bool *overflow_p) |
2684 | { | |
2685 | int i; | |
2686 | tree args[3]; | |
2687 | tree val; | |
2688 | ||
2689 | for (i = 0; i < 3; i++) | |
2690 | { | |
cf72f34d | 2691 | args[i] = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, i), |
1227ba74 | 2692 | lval, |
b2a43197 | 2693 | non_constant_p, overflow_p); |
09b42213 | 2694 | VERIFY_CONSTANT (args[i]); |
2695 | } | |
2696 | ||
2697 | val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t), | |
2698 | args[0], args[1], args[2]); | |
2699 | if (val == NULL_TREE) | |
2700 | return t; | |
2701 | VERIFY_CONSTANT (val); | |
2702 | return val; | |
2703 | } | |
2704 | ||
2705 | bool | |
2706 | var_in_constexpr_fn (tree t) | |
2707 | { | |
2708 | tree ctx = DECL_CONTEXT (t); | |
2709 | return (cxx_dialect >= cxx14 && ctx && TREE_CODE (ctx) == FUNCTION_DECL | |
2710 | && DECL_DECLARED_CONSTEXPR_P (ctx)); | |
2711 | } | |
2712 | ||
9c96033c | 2713 | /* Evaluate an INIT_EXPR or MODIFY_EXPR. */ |
2714 | ||
2715 | static tree | |
2716 | cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 2717 | bool lval, |
9c96033c | 2718 | bool *non_constant_p, bool *overflow_p) |
2719 | { | |
2720 | constexpr_ctx new_ctx = *ctx; | |
2721 | ||
8a36d0ec | 2722 | tree init = TREE_OPERAND (t, 1); |
2723 | if (TREE_CLOBBER_P (init)) | |
2724 | /* Just ignore clobbers. */ | |
2725 | return void_node; | |
2726 | ||
9c96033c | 2727 | /* First we figure out where we're storing to. */ |
2728 | tree target = TREE_OPERAND (t, 0); | |
9db9fc38 | 2729 | tree type = TREE_TYPE (target); |
9c96033c | 2730 | target = cxx_eval_constant_expression (ctx, target, |
f83e6885 | 2731 | true, |
b2a43197 | 2732 | non_constant_p, overflow_p); |
9c96033c | 2733 | if (*non_constant_p) |
2734 | return t; | |
2735 | ||
9db9fc38 | 2736 | if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (target), type)) |
2737 | { | |
2738 | /* For initialization of an empty base, the original target will be | |
2739 | *(base*)this, which the above evaluation resolves to the object | |
2740 | argument, which has the derived type rather than the base type. In | |
2741 | this situation, just evaluate the initializer and return, since | |
2742 | there's no actual data to store. */ | |
2743 | gcc_assert (is_empty_class (type)); | |
2744 | return cxx_eval_constant_expression (ctx, init, false, | |
2745 | non_constant_p, overflow_p); | |
2746 | } | |
2747 | ||
9c96033c | 2748 | /* And then find the underlying variable. */ |
2749 | vec<tree,va_gc> *refs = make_tree_vector(); | |
2750 | tree object = NULL_TREE; | |
2751 | for (tree probe = target; object == NULL_TREE; ) | |
2752 | { | |
2753 | switch (TREE_CODE (probe)) | |
2754 | { | |
2755 | case BIT_FIELD_REF: | |
2756 | case COMPONENT_REF: | |
2757 | case ARRAY_REF: | |
2758 | vec_safe_push (refs, TREE_OPERAND (probe, 1)); | |
2759 | vec_safe_push (refs, TREE_TYPE (probe)); | |
2760 | probe = TREE_OPERAND (probe, 0); | |
2761 | break; | |
2762 | ||
2763 | default: | |
2764 | object = probe; | |
9c96033c | 2765 | } |
2766 | } | |
2767 | ||
2768 | /* And then find/build up our initializer for the path to the subobject | |
2769 | we're initializing. */ | |
6fe83e54 | 2770 | tree *valp; |
2771 | if (DECL_P (object)) | |
2772 | valp = ctx->values->get (object); | |
2773 | else | |
2774 | valp = NULL; | |
9c96033c | 2775 | if (!valp) |
2776 | { | |
2777 | /* A constant-expression cannot modify objects from outside the | |
2778 | constant-expression. */ | |
f83e6885 | 2779 | if (!ctx->quiet) |
6fe83e54 | 2780 | error ("modification of %qE is not a constant-expression", object); |
9c96033c | 2781 | *non_constant_p = true; |
2782 | return t; | |
2783 | } | |
9db9fc38 | 2784 | type = TREE_TYPE (object); |
a02b42fe | 2785 | bool no_zero_init = true; |
9c96033c | 2786 | while (!refs->is_empty()) |
2787 | { | |
2788 | if (*valp == NULL_TREE) | |
2789 | { | |
2790 | *valp = build_constructor (type, NULL); | |
a02b42fe | 2791 | CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp) = no_zero_init; |
9c96033c | 2792 | } |
a02b42fe | 2793 | /* If the value of object is already zero-initialized, any new ctors for |
2794 | subobjects will also be zero-initialized. */ | |
2795 | no_zero_init = CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp); | |
9c96033c | 2796 | |
7963b19d | 2797 | enum tree_code code = TREE_CODE (type); |
9c96033c | 2798 | type = refs->pop(); |
7963b19d | 2799 | tree index = refs->pop(); |
9c96033c | 2800 | |
9c96033c | 2801 | constructor_elt *cep = NULL; |
7963b19d | 2802 | if (code == ARRAY_TYPE) |
2803 | { | |
2804 | HOST_WIDE_INT i | |
2805 | = find_array_ctor_elt (*valp, index, /*insert*/true); | |
2806 | gcc_assert (i >= 0); | |
2807 | cep = CONSTRUCTOR_ELT (*valp, i); | |
2808 | gcc_assert (TREE_CODE (cep->index) != RANGE_EXPR); | |
2809 | } | |
2810 | else | |
2811 | { | |
2812 | gcc_assert (TREE_CODE (index) == FIELD_DECL); | |
2813 | for (unsigned HOST_WIDE_INT idx = 0; | |
2814 | vec_safe_iterate (CONSTRUCTOR_ELTS (*valp), idx, &cep); | |
2815 | idx++) | |
2816 | if (index == cep->index) | |
2817 | break; | |
2818 | if (!cep) | |
2819 | { | |
2820 | constructor_elt ce = { index, NULL_TREE }; | |
2821 | cep = vec_safe_push (CONSTRUCTOR_ELTS (*valp), ce); | |
2822 | } | |
2823 | } | |
9c96033c | 2824 | valp = &cep->value; |
2825 | } | |
2826 | release_tree_vector (refs); | |
2827 | ||
469dc5a6 | 2828 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) |
9c96033c | 2829 | { |
2830 | /* Create a new CONSTRUCTOR in case evaluation of the initializer | |
2831 | wants to modify it. */ | |
469dc5a6 | 2832 | if (*valp == NULL_TREE) |
6cded085 | 2833 | { |
2834 | *valp = new_ctx.ctor = build_constructor (type, NULL); | |
2835 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = no_zero_init; | |
2836 | } | |
2837 | else | |
2838 | new_ctx.ctor = *valp; | |
9c96033c | 2839 | new_ctx.object = target; |
2840 | } | |
2841 | ||
8a36d0ec | 2842 | init = cxx_eval_constant_expression (&new_ctx, init, false, |
2843 | non_constant_p, overflow_p); | |
9c96033c | 2844 | if (target == object) |
469dc5a6 | 2845 | { |
2846 | /* The hash table might have moved since the get earlier. */ | |
2847 | valp = ctx->values->get (object); | |
2848 | if (TREE_CODE (init) == CONSTRUCTOR) | |
2849 | /* An outer ctx->ctor might be pointing to *valp, so just replace | |
2850 | its contents. */ | |
2851 | CONSTRUCTOR_ELTS (*valp) = CONSTRUCTOR_ELTS (init); | |
2852 | else | |
2853 | *valp = init; | |
2854 | } | |
9c96033c | 2855 | else |
2856 | *valp = init; | |
2857 | ||
2858 | if (*non_constant_p) | |
2859 | return t; | |
1227ba74 | 2860 | else if (lval) |
9c96033c | 2861 | return target; |
2862 | else | |
dfac7dd2 | 2863 | return init; |
9c96033c | 2864 | } |
2865 | ||
2866 | /* Evaluate a ++ or -- expression. */ | |
2867 | ||
2868 | static tree | |
2869 | cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 2870 | bool lval, |
9c96033c | 2871 | bool *non_constant_p, bool *overflow_p) |
2872 | { | |
2873 | enum tree_code code = TREE_CODE (t); | |
2874 | tree type = TREE_TYPE (t); | |
2875 | tree op = TREE_OPERAND (t, 0); | |
2876 | tree offset = TREE_OPERAND (t, 1); | |
2877 | gcc_assert (TREE_CONSTANT (offset)); | |
2878 | ||
2879 | /* The operand as an lvalue. */ | |
f83e6885 | 2880 | op = cxx_eval_constant_expression (ctx, op, true, |
b2a43197 | 2881 | non_constant_p, overflow_p); |
9c96033c | 2882 | |
2883 | /* The operand as an rvalue. */ | |
2884 | tree val = rvalue (op); | |
f83e6885 | 2885 | val = cxx_eval_constant_expression (ctx, val, false, |
b2a43197 | 2886 | non_constant_p, overflow_p); |
35f2c28f | 2887 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
2888 | a local array in a constexpr function. */ | |
2889 | bool ptr = POINTER_TYPE_P (TREE_TYPE (val)); | |
2890 | if (!ptr) | |
2891 | VERIFY_CONSTANT (val); | |
9c96033c | 2892 | |
2893 | /* The modified value. */ | |
2894 | bool inc = (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR); | |
c8a8f7ad | 2895 | tree mod; |
2896 | if (POINTER_TYPE_P (type)) | |
2897 | { | |
2898 | /* The middle end requires pointers to use POINTER_PLUS_EXPR. */ | |
2899 | offset = convert_to_ptrofftype (offset); | |
2900 | if (!inc) | |
2901 | offset = fold_build1 (NEGATE_EXPR, TREE_TYPE (offset), offset); | |
2902 | mod = fold_build2 (POINTER_PLUS_EXPR, type, val, offset); | |
2903 | } | |
2904 | else | |
2905 | mod = fold_build2 (inc ? PLUS_EXPR : MINUS_EXPR, type, val, offset); | |
35f2c28f | 2906 | if (!ptr) |
2907 | VERIFY_CONSTANT (mod); | |
9c96033c | 2908 | |
2909 | /* Storing the modified value. */ | |
2910 | tree store = build2 (MODIFY_EXPR, type, op, mod); | |
f83e6885 | 2911 | cxx_eval_constant_expression (ctx, store, |
b2a43197 | 2912 | true, non_constant_p, overflow_p); |
9c96033c | 2913 | |
2914 | /* And the value of the expression. */ | |
2915 | if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) | |
2916 | { | |
2917 | /* Prefix ops are lvalues. */ | |
1227ba74 | 2918 | if (lval) |
9c96033c | 2919 | return op; |
2920 | else | |
2921 | /* But we optimize when the caller wants an rvalue. */ | |
2922 | return mod; | |
2923 | } | |
2924 | else | |
2925 | /* Postfix ops are rvalues. */ | |
2926 | return val; | |
2927 | } | |
2928 | ||
00f21715 | 2929 | /* Predicates for the meaning of *jump_target. */ |
2930 | ||
2931 | static bool | |
2932 | returns (tree *jump_target) | |
2933 | { | |
2934 | return *jump_target | |
2935 | && TREE_CODE (*jump_target) == RETURN_EXPR; | |
2936 | } | |
2937 | ||
2938 | static bool | |
2939 | breaks (tree *jump_target) | |
2940 | { | |
2941 | return *jump_target | |
2942 | && TREE_CODE (*jump_target) == LABEL_DECL | |
2943 | && LABEL_DECL_BREAK (*jump_target); | |
2944 | } | |
2945 | ||
2946 | static bool | |
2947 | continues (tree *jump_target) | |
2948 | { | |
2949 | return *jump_target | |
2950 | && TREE_CODE (*jump_target) == LABEL_DECL | |
2951 | && LABEL_DECL_CONTINUE (*jump_target); | |
2952 | } | |
2953 | ||
2954 | static bool | |
2955 | switches (tree *jump_target) | |
2956 | { | |
2957 | return *jump_target | |
2958 | && TREE_CODE (*jump_target) == INTEGER_CST; | |
2959 | } | |
2960 | ||
2961 | /* Subroutine of cxx_eval_statement_list. Determine whether the statement | |
2962 | at I matches *jump_target. If we're looking for a case label and we see | |
2963 | the default label, copy I into DEFAULT_LABEL. */ | |
2964 | ||
2965 | static bool | |
2966 | label_matches (tree *jump_target, tree_stmt_iterator i, | |
2967 | tree_stmt_iterator& default_label) | |
2968 | { | |
2969 | tree stmt = tsi_stmt (i); | |
2970 | switch (TREE_CODE (*jump_target)) | |
2971 | { | |
2972 | case LABEL_DECL: | |
2973 | if (TREE_CODE (stmt) == LABEL_EXPR | |
2974 | && LABEL_EXPR_LABEL (stmt) == *jump_target) | |
2975 | return true; | |
2976 | break; | |
2977 | ||
2978 | case INTEGER_CST: | |
2979 | if (TREE_CODE (stmt) == CASE_LABEL_EXPR) | |
2980 | { | |
2981 | if (!CASE_LOW (stmt)) | |
2982 | default_label = i; | |
2983 | else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt))) | |
2984 | return true; | |
2985 | } | |
2986 | break; | |
2987 | ||
2988 | default: | |
2989 | gcc_unreachable (); | |
2990 | } | |
2991 | return false; | |
2992 | } | |
2993 | ||
2994 | /* Evaluate a STATEMENT_LIST for side-effects. Handles various jump | |
2995 | semantics, for switch, break, continue, and return. */ | |
2996 | ||
2997 | static tree | |
2998 | cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, | |
00f21715 | 2999 | bool *non_constant_p, bool *overflow_p, |
3000 | tree *jump_target) | |
3001 | { | |
3002 | tree_stmt_iterator i; | |
3003 | tree_stmt_iterator default_label = tree_stmt_iterator(); | |
da7981e0 | 3004 | tree local_target; |
3005 | /* In a statement-expression we want to return the last value. */ | |
3006 | tree r = NULL_TREE; | |
3007 | if (!jump_target) | |
3008 | { | |
3009 | local_target = NULL_TREE; | |
3010 | jump_target = &local_target; | |
3011 | } | |
00f21715 | 3012 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) |
3013 | { | |
3014 | reenter: | |
3015 | tree stmt = tsi_stmt (i); | |
3016 | if (*jump_target) | |
3017 | { | |
3018 | if (TREE_CODE (stmt) == STATEMENT_LIST) | |
3019 | /* The label we want might be inside. */; | |
3020 | else if (label_matches (jump_target, i, default_label)) | |
3021 | /* Found it. */ | |
3022 | *jump_target = NULL_TREE; | |
3023 | else | |
3024 | continue; | |
3025 | } | |
da7981e0 | 3026 | r = cxx_eval_constant_expression (ctx, stmt, false, |
3027 | non_constant_p, overflow_p, | |
3028 | jump_target); | |
00f21715 | 3029 | if (*non_constant_p) |
3030 | break; | |
3031 | if (returns (jump_target) || breaks (jump_target)) | |
3032 | break; | |
3033 | } | |
3034 | if (switches (jump_target) && !tsi_end_p (default_label)) | |
3035 | { | |
3036 | i = default_label; | |
3037 | *jump_target = NULL_TREE; | |
3038 | goto reenter; | |
3039 | } | |
da7981e0 | 3040 | return r; |
00f21715 | 3041 | } |
3042 | ||
3043 | /* Evaluate a LOOP_EXPR for side-effects. Handles break and return | |
3044 | semantics; continue semantics are covered by cxx_eval_statement_list. */ | |
3045 | ||
3046 | static tree | |
3047 | cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3048 | bool *non_constant_p, bool *overflow_p, |
3049 | tree *jump_target) | |
3050 | { | |
3051 | tree body = TREE_OPERAND (t, 0); | |
3052 | while (true) | |
3053 | { | |
f83e6885 | 3054 | cxx_eval_statement_list (ctx, body, |
00f21715 | 3055 | non_constant_p, overflow_p, jump_target); |
b0295f63 | 3056 | if (returns (jump_target) || breaks (jump_target) || *non_constant_p) |
00f21715 | 3057 | break; |
3058 | } | |
3059 | if (breaks (jump_target)) | |
3060 | *jump_target = NULL_TREE; | |
3061 | return NULL_TREE; | |
3062 | } | |
3063 | ||
3064 | /* Evaluate a SWITCH_EXPR for side-effects. Handles switch and break jump | |
3065 | semantics. */ | |
3066 | ||
3067 | static tree | |
3068 | cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3069 | bool *non_constant_p, bool *overflow_p, |
3070 | tree *jump_target) | |
3071 | { | |
3072 | tree cond = TREE_OPERAND (t, 0); | |
f83e6885 | 3073 | cond = cxx_eval_constant_expression (ctx, cond, false, |
b2a43197 | 3074 | non_constant_p, overflow_p); |
00f21715 | 3075 | VERIFY_CONSTANT (cond); |
3076 | *jump_target = cond; | |
3077 | ||
3078 | tree body = TREE_OPERAND (t, 1); | |
f83e6885 | 3079 | cxx_eval_statement_list (ctx, body, |
00f21715 | 3080 | non_constant_p, overflow_p, jump_target); |
3081 | if (breaks (jump_target) || switches (jump_target)) | |
3082 | *jump_target = NULL_TREE; | |
3083 | return NULL_TREE; | |
3084 | } | |
3085 | ||
35b68da8 | 3086 | /* Subroutine of cxx_eval_constant_expression. |
3087 | Attempt to reduce a POINTER_PLUS_EXPR expression T. */ | |
3088 | ||
3089 | static tree | |
3090 | cxx_eval_pointer_plus_expression (const constexpr_ctx *ctx, tree t, | |
3091 | bool lval, bool *non_constant_p, | |
3092 | bool *overflow_p) | |
3093 | { | |
51a019c5 | 3094 | tree orig_type = TREE_TYPE (t); |
35b68da8 | 3095 | tree op00 = TREE_OPERAND (t, 0); |
3096 | tree op01 = TREE_OPERAND (t, 1); | |
3097 | location_t loc = EXPR_LOCATION (t); | |
3098 | ||
f070a770 | 3099 | op00 = cxx_eval_constant_expression (ctx, op00, lval, |
3100 | non_constant_p, overflow_p); | |
3101 | ||
35b68da8 | 3102 | STRIP_NOPS (op00); |
3103 | if (TREE_CODE (op00) != ADDR_EXPR) | |
3104 | return NULL_TREE; | |
3105 | ||
d2c63826 | 3106 | op01 = cxx_eval_constant_expression (ctx, op01, lval, |
3107 | non_constant_p, overflow_p); | |
35b68da8 | 3108 | op00 = TREE_OPERAND (op00, 0); |
3109 | ||
3110 | /* &A[i] p+ j => &A[i + j] */ | |
3111 | if (TREE_CODE (op00) == ARRAY_REF | |
3112 | && TREE_CODE (TREE_OPERAND (op00, 1)) == INTEGER_CST | |
51a019c5 | 3113 | && TREE_CODE (op01) == INTEGER_CST |
3114 | && TYPE_SIZE_UNIT (TREE_TYPE (op00)) | |
3115 | && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (op00))) == INTEGER_CST) | |
35b68da8 | 3116 | { |
3117 | tree type = TREE_TYPE (op00); | |
3118 | t = fold_convert_loc (loc, ssizetype, TREE_OPERAND (op00, 1)); | |
3119 | tree nelts = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (op00, 0))); | |
3120 | /* Don't fold an out-of-bound access. */ | |
3121 | if (!tree_int_cst_le (t, nelts)) | |
3122 | return NULL_TREE; | |
51a019c5 | 3123 | op01 = cp_fold_convert (ssizetype, op01); |
3124 | /* Don't fold if op01 can't be divided exactly by TYPE_SIZE_UNIT. | |
3125 | constexpr int A[1]; ... (char *)&A[0] + 1 */ | |
3126 | if (!integer_zerop (fold_build2_loc (loc, TRUNC_MOD_EXPR, sizetype, | |
3127 | op01, TYPE_SIZE_UNIT (type)))) | |
3128 | return NULL_TREE; | |
35b68da8 | 3129 | /* Make sure to treat the second operand of POINTER_PLUS_EXPR |
3130 | as signed. */ | |
51a019c5 | 3131 | op01 = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, op01, |
35b68da8 | 3132 | TYPE_SIZE_UNIT (type)); |
3133 | t = size_binop_loc (loc, PLUS_EXPR, op01, t); | |
3134 | t = build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (op00, 0), | |
3135 | t, NULL_TREE, NULL_TREE); | |
3136 | t = cp_build_addr_expr (t, tf_warning_or_error); | |
51a019c5 | 3137 | t = cp_fold_convert (orig_type, t); |
35b68da8 | 3138 | return cxx_eval_constant_expression (ctx, t, lval, non_constant_p, |
3139 | overflow_p); | |
3140 | } | |
3141 | ||
3142 | return NULL_TREE; | |
3143 | } | |
3144 | ||
09b42213 | 3145 | /* Attempt to reduce the expression T to a constant value. |
3146 | On failure, issue diagnostic and return error_mark_node. */ | |
3147 | /* FIXME unify with c_fully_fold */ | |
9c96033c | 3148 | /* FIXME overflow_p is too global */ |
09b42213 | 3149 | |
3150 | static tree | |
cf72f34d | 3151 | cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3152 | bool lval, |
00f21715 | 3153 | bool *non_constant_p, bool *overflow_p, |
3154 | tree *jump_target) | |
09b42213 | 3155 | { |
cf72f34d | 3156 | constexpr_ctx new_ctx; |
09b42213 | 3157 | tree r = t; |
3158 | ||
3159 | if (t == error_mark_node) | |
3160 | { | |
3161 | *non_constant_p = true; | |
3162 | return t; | |
3163 | } | |
3164 | if (CONSTANT_CLASS_P (t)) | |
3165 | { | |
f16ed232 | 3166 | if (TREE_OVERFLOW (t) && (!flag_permissive || ctx->quiet)) |
09b42213 | 3167 | *overflow_p = true; |
3168 | return t; | |
3169 | } | |
09b42213 | 3170 | |
3171 | switch (TREE_CODE (t)) | |
3172 | { | |
9c96033c | 3173 | case RESULT_DECL: |
1227ba74 | 3174 | if (lval) |
9c96033c | 3175 | return t; |
3176 | /* We ask for an rvalue for the RESULT_DECL when indirecting | |
92a9c89e | 3177 | through an invisible reference, or in named return value |
3178 | optimization. */ | |
9c96033c | 3179 | return (*ctx->values->get (t)); |
3180 | ||
09b42213 | 3181 | case VAR_DECL: |
8b2b2f24 | 3182 | case CONST_DECL: |
3183 | /* We used to not check lval for CONST_DECL, but darwin.c uses | |
3184 | CONST_DECL for aggregate constants. */ | |
1227ba74 | 3185 | if (lval) |
09b42213 | 3186 | return t; |
2055d27a | 3187 | if (ctx->strict) |
3188 | r = decl_really_constant_value (t); | |
3189 | else | |
3190 | r = decl_constant_value (t); | |
09b42213 | 3191 | if (TREE_CODE (r) == TARGET_EXPR |
3192 | && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR) | |
3193 | r = TARGET_EXPR_INITIAL (r); | |
f4ae4202 | 3194 | if (VAR_P (r)) |
cf72f34d | 3195 | if (tree *p = ctx->values->get (r)) |
a143e277 | 3196 | if (*p != NULL_TREE) |
3197 | r = *p; | |
09b42213 | 3198 | if (DECL_P (r)) |
3199 | { | |
f83e6885 | 3200 | if (!ctx->quiet) |
09b42213 | 3201 | non_const_var_error (r); |
3202 | *non_constant_p = true; | |
3203 | } | |
3204 | break; | |
3205 | ||
3206 | case FUNCTION_DECL: | |
3207 | case TEMPLATE_DECL: | |
3208 | case LABEL_DECL: | |
00f21715 | 3209 | case LABEL_EXPR: |
3210 | case CASE_LABEL_EXPR: | |
09b42213 | 3211 | return t; |
3212 | ||
3213 | case PARM_DECL: | |
88a59139 | 3214 | if (lval && TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE) |
9c96033c | 3215 | /* glvalue use. */; |
3216 | else if (tree *p = ctx->values->get (r)) | |
3217 | r = *p; | |
1227ba74 | 3218 | else if (lval) |
09b42213 | 3219 | /* Defer in case this is only used for its type. */; |
1eb418cc | 3220 | else if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE) |
3221 | /* Defer, there's no lvalue->rvalue conversion. */; | |
a6613de7 | 3222 | else if (is_empty_class (TREE_TYPE (t))) |
3223 | { | |
3224 | /* If the class is empty, we aren't actually loading anything. */ | |
3225 | r = build_constructor (TREE_TYPE (t), NULL); | |
3226 | TREE_CONSTANT (r) = true; | |
3227 | } | |
09b42213 | 3228 | else |
3229 | { | |
f83e6885 | 3230 | if (!ctx->quiet) |
09b42213 | 3231 | error ("%qE is not a constant expression", t); |
3232 | *non_constant_p = true; | |
3233 | } | |
3234 | break; | |
3235 | ||
3236 | case CALL_EXPR: | |
3237 | case AGGR_INIT_EXPR: | |
1227ba74 | 3238 | r = cxx_eval_call_expression (ctx, t, lval, |
09b42213 | 3239 | non_constant_p, overflow_p); |
3240 | break; | |
3241 | ||
9c96033c | 3242 | case DECL_EXPR: |
3243 | { | |
3244 | r = DECL_EXPR_DECL (t); | |
3245 | if (AGGREGATE_TYPE_P (TREE_TYPE (r)) | |
3246 | || VECTOR_TYPE_P (TREE_TYPE (r))) | |
3247 | { | |
3248 | new_ctx = *ctx; | |
3249 | new_ctx.object = r; | |
3250 | new_ctx.ctor = build_constructor (TREE_TYPE (r), NULL); | |
3251 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
3252 | new_ctx.values->put (r, new_ctx.ctor); | |
3253 | ctx = &new_ctx; | |
3254 | } | |
3255 | ||
3256 | if (tree init = DECL_INITIAL (r)) | |
3257 | { | |
3258 | init = cxx_eval_constant_expression (ctx, init, | |
f83e6885 | 3259 | false, |
b2a43197 | 3260 | non_constant_p, overflow_p); |
9c96033c | 3261 | ctx->values->put (r, init); |
3262 | } | |
3263 | else if (ctx == &new_ctx) | |
3264 | /* We gave it a CONSTRUCTOR above. */; | |
3265 | else | |
3266 | ctx->values->put (r, NULL_TREE); | |
3267 | } | |
3268 | break; | |
3269 | ||
09b42213 | 3270 | case TARGET_EXPR: |
3271 | if (!literal_type_p (TREE_TYPE (t))) | |
3272 | { | |
f83e6885 | 3273 | if (!ctx->quiet) |
09b42213 | 3274 | { |
3275 | error ("temporary of non-literal type %qT in a " | |
3276 | "constant expression", TREE_TYPE (t)); | |
3277 | explain_non_literal_class (TREE_TYPE (t)); | |
3278 | } | |
3279 | *non_constant_p = true; | |
3280 | break; | |
3281 | } | |
cf72f34d | 3282 | if ((AGGREGATE_TYPE_P (TREE_TYPE (t)) || VECTOR_TYPE_P (TREE_TYPE (t)))) |
3283 | { | |
3284 | /* We're being expanded without an explicit target, so start | |
3285 | initializing a new object; expansion with an explicit target | |
3286 | strips the TARGET_EXPR before we get here. */ | |
3287 | new_ctx = *ctx; | |
3288 | new_ctx.ctor = build_constructor (TREE_TYPE (t), NULL); | |
3289 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
3290 | new_ctx.object = TARGET_EXPR_SLOT (t); | |
3291 | ctx->values->put (new_ctx.object, new_ctx.ctor); | |
3292 | ctx = &new_ctx; | |
3293 | } | |
1227ba74 | 3294 | /* Pass false for 'lval' because this indicates |
09b42213 | 3295 | initialization of a temporary. */ |
cf72f34d | 3296 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 3297 | false, |
b2a43197 | 3298 | non_constant_p, overflow_p); |
09b42213 | 3299 | if (!*non_constant_p) |
3300 | /* Adjust the type of the result to the type of the temporary. */ | |
3301 | r = adjust_temp_type (TREE_TYPE (t), r); | |
1227ba74 | 3302 | if (lval) |
1eb418cc | 3303 | { |
3304 | tree slot = TARGET_EXPR_SLOT (t); | |
3305 | ctx->values->put (slot, r); | |
3306 | return slot; | |
3307 | } | |
09b42213 | 3308 | break; |
3309 | ||
9c96033c | 3310 | case INIT_EXPR: |
9c96033c | 3311 | case MODIFY_EXPR: |
1227ba74 | 3312 | r = cxx_eval_store_expression (ctx, t, lval, |
9c96033c | 3313 | non_constant_p, overflow_p); |
3314 | break; | |
3315 | ||
09b42213 | 3316 | case SCOPE_REF: |
cf72f34d | 3317 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 3318 | lval, |
b2a43197 | 3319 | non_constant_p, overflow_p); |
09b42213 | 3320 | break; |
3321 | ||
3322 | case RETURN_EXPR: | |
10fb495c | 3323 | if (TREE_OPERAND (t, 0) != NULL_TREE) |
3324 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
3325 | lval, | |
3326 | non_constant_p, overflow_p); | |
00f21715 | 3327 | *jump_target = t; |
3328 | break; | |
3329 | ||
e0e672a0 | 3330 | case SAVE_EXPR: |
3331 | /* Avoid evaluating a SAVE_EXPR more than once. */ | |
3332 | if (tree *p = ctx->values->get (t)) | |
3333 | r = *p; | |
3334 | else | |
3335 | { | |
c8f6aeb1 | 3336 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), false, |
e0e672a0 | 3337 | non_constant_p, overflow_p); |
3338 | ctx->values->put (t, r); | |
3339 | } | |
3340 | break; | |
3341 | ||
09b42213 | 3342 | case NON_LVALUE_EXPR: |
3343 | case TRY_CATCH_EXPR: | |
7f67d68c | 3344 | case TRY_BLOCK: |
09b42213 | 3345 | case CLEANUP_POINT_EXPR: |
3346 | case MUST_NOT_THROW_EXPR: | |
9c96033c | 3347 | case EXPR_STMT: |
3348 | case EH_SPEC_BLOCK: | |
cf72f34d | 3349 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 3350 | lval, |
00f21715 | 3351 | non_constant_p, overflow_p, |
3352 | jump_target); | |
09b42213 | 3353 | break; |
3354 | ||
7f67d68c | 3355 | case TRY_FINALLY_EXPR: |
3356 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
3357 | non_constant_p, overflow_p, | |
3358 | jump_target); | |
3359 | if (!*non_constant_p) | |
3360 | /* Also evaluate the cleanup. */ | |
3361 | cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), true, | |
3362 | non_constant_p, overflow_p, | |
3363 | jump_target); | |
3364 | break; | |
3365 | ||
09b42213 | 3366 | /* These differ from cxx_eval_unary_expression in that this doesn't |
3367 | check for a constant operand or result; an address can be | |
3368 | constant without its operand being, and vice versa. */ | |
d2c63826 | 3369 | case MEM_REF: |
09b42213 | 3370 | case INDIRECT_REF: |
1227ba74 | 3371 | r = cxx_eval_indirect_ref (ctx, t, lval, |
09b42213 | 3372 | non_constant_p, overflow_p); |
3373 | break; | |
3374 | ||
3375 | case ADDR_EXPR: | |
3376 | { | |
3377 | tree oldop = TREE_OPERAND (t, 0); | |
cf72f34d | 3378 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 3379 | /*lval*/true, |
b2a43197 | 3380 | non_constant_p, overflow_p); |
09b42213 | 3381 | /* Don't VERIFY_CONSTANT here. */ |
3382 | if (*non_constant_p) | |
3383 | return t; | |
1eb418cc | 3384 | gcc_checking_assert (TREE_CODE (op) != CONSTRUCTOR); |
09b42213 | 3385 | /* This function does more aggressive folding than fold itself. */ |
3386 | r = build_fold_addr_expr_with_type (op, TREE_TYPE (t)); | |
3387 | if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop) | |
3388 | return t; | |
3389 | break; | |
3390 | } | |
3391 | ||
3392 | case REALPART_EXPR: | |
3393 | case IMAGPART_EXPR: | |
3394 | case CONJ_EXPR: | |
3395 | case FIX_TRUNC_EXPR: | |
3396 | case FLOAT_EXPR: | |
3397 | case NEGATE_EXPR: | |
3398 | case ABS_EXPR: | |
3399 | case BIT_NOT_EXPR: | |
3400 | case TRUTH_NOT_EXPR: | |
3401 | case FIXED_CONVERT_EXPR: | |
1227ba74 | 3402 | r = cxx_eval_unary_expression (ctx, t, lval, |
09b42213 | 3403 | non_constant_p, overflow_p); |
3404 | break; | |
3405 | ||
3406 | case SIZEOF_EXPR: | |
d2c63826 | 3407 | r = fold_sizeof_expr (t); |
09b42213 | 3408 | VERIFY_CONSTANT (r); |
3409 | break; | |
3410 | ||
3411 | case COMPOUND_EXPR: | |
3412 | { | |
3413 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
3414 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
3415 | introduced by build_call_a. */ | |
3416 | tree op0 = TREE_OPERAND (t, 0); | |
3417 | tree op1 = TREE_OPERAND (t, 1); | |
3418 | STRIP_NOPS (op1); | |
3419 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
3420 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
f83e6885 | 3421 | r = cxx_eval_constant_expression (ctx, op0, |
1227ba74 | 3422 | lval, non_constant_p, overflow_p, |
00f21715 | 3423 | jump_target); |
09b42213 | 3424 | else |
3425 | { | |
3426 | /* Check that the LHS is constant and then discard it. */ | |
f83e6885 | 3427 | cxx_eval_constant_expression (ctx, op0, |
c8f6aeb1 | 3428 | true, non_constant_p, overflow_p, |
00f21715 | 3429 | jump_target); |
09b42213 | 3430 | op1 = TREE_OPERAND (t, 1); |
f83e6885 | 3431 | r = cxx_eval_constant_expression (ctx, op1, |
1227ba74 | 3432 | lval, non_constant_p, overflow_p, |
00f21715 | 3433 | jump_target); |
09b42213 | 3434 | } |
3435 | } | |
3436 | break; | |
3437 | ||
3438 | case POINTER_PLUS_EXPR: | |
35b68da8 | 3439 | r = cxx_eval_pointer_plus_expression (ctx, t, lval, non_constant_p, |
3440 | overflow_p); | |
3441 | if (r) | |
3442 | break; | |
3443 | /* else fall through */ | |
3444 | ||
09b42213 | 3445 | case PLUS_EXPR: |
3446 | case MINUS_EXPR: | |
3447 | case MULT_EXPR: | |
3448 | case TRUNC_DIV_EXPR: | |
3449 | case CEIL_DIV_EXPR: | |
3450 | case FLOOR_DIV_EXPR: | |
3451 | case ROUND_DIV_EXPR: | |
3452 | case TRUNC_MOD_EXPR: | |
3453 | case CEIL_MOD_EXPR: | |
3454 | case ROUND_MOD_EXPR: | |
3455 | case RDIV_EXPR: | |
3456 | case EXACT_DIV_EXPR: | |
3457 | case MIN_EXPR: | |
3458 | case MAX_EXPR: | |
3459 | case LSHIFT_EXPR: | |
3460 | case RSHIFT_EXPR: | |
3461 | case LROTATE_EXPR: | |
3462 | case RROTATE_EXPR: | |
3463 | case BIT_IOR_EXPR: | |
3464 | case BIT_XOR_EXPR: | |
3465 | case BIT_AND_EXPR: | |
3466 | case TRUTH_XOR_EXPR: | |
3467 | case LT_EXPR: | |
3468 | case LE_EXPR: | |
3469 | case GT_EXPR: | |
3470 | case GE_EXPR: | |
3471 | case EQ_EXPR: | |
3472 | case NE_EXPR: | |
3473 | case UNORDERED_EXPR: | |
3474 | case ORDERED_EXPR: | |
3475 | case UNLT_EXPR: | |
3476 | case UNLE_EXPR: | |
3477 | case UNGT_EXPR: | |
3478 | case UNGE_EXPR: | |
3479 | case UNEQ_EXPR: | |
3480 | case LTGT_EXPR: | |
3481 | case RANGE_EXPR: | |
3482 | case COMPLEX_EXPR: | |
1227ba74 | 3483 | r = cxx_eval_binary_expression (ctx, t, lval, |
09b42213 | 3484 | non_constant_p, overflow_p); |
3485 | break; | |
3486 | ||
3487 | /* fold can introduce non-IF versions of these; still treat them as | |
3488 | short-circuiting. */ | |
3489 | case TRUTH_AND_EXPR: | |
3490 | case TRUTH_ANDIF_EXPR: | |
cf72f34d | 3491 | r = cxx_eval_logical_expression (ctx, t, boolean_false_node, |
09b42213 | 3492 | boolean_true_node, |
1227ba74 | 3493 | lval, |
09b42213 | 3494 | non_constant_p, overflow_p); |
3495 | break; | |
3496 | ||
3497 | case TRUTH_OR_EXPR: | |
3498 | case TRUTH_ORIF_EXPR: | |
cf72f34d | 3499 | r = cxx_eval_logical_expression (ctx, t, boolean_true_node, |
09b42213 | 3500 | boolean_false_node, |
1227ba74 | 3501 | lval, |
09b42213 | 3502 | non_constant_p, overflow_p); |
3503 | break; | |
3504 | ||
3505 | case ARRAY_REF: | |
1227ba74 | 3506 | r = cxx_eval_array_reference (ctx, t, lval, |
09b42213 | 3507 | non_constant_p, overflow_p); |
3508 | break; | |
3509 | ||
3510 | case COMPONENT_REF: | |
3511 | if (is_overloaded_fn (t)) | |
3512 | { | |
3513 | /* We can only get here in checking mode via | |
3514 | build_non_dependent_expr, because any expression that | |
3515 | calls or takes the address of the function will have | |
3516 | pulled a FUNCTION_DECL out of the COMPONENT_REF. */ | |
f83e6885 | 3517 | gcc_checking_assert (ctx->quiet || errorcount); |
09b42213 | 3518 | *non_constant_p = true; |
3519 | return t; | |
3520 | } | |
1227ba74 | 3521 | r = cxx_eval_component_reference (ctx, t, lval, |
09b42213 | 3522 | non_constant_p, overflow_p); |
3523 | break; | |
3524 | ||
3525 | case BIT_FIELD_REF: | |
1227ba74 | 3526 | r = cxx_eval_bit_field_ref (ctx, t, lval, |
09b42213 | 3527 | non_constant_p, overflow_p); |
3528 | break; | |
3529 | ||
3530 | case COND_EXPR: | |
3531 | case VEC_COND_EXPR: | |
1227ba74 | 3532 | r = cxx_eval_conditional_expression (ctx, t, lval, |
00f21715 | 3533 | non_constant_p, overflow_p, |
3534 | jump_target); | |
09b42213 | 3535 | break; |
3536 | ||
3537 | case CONSTRUCTOR: | |
1a3631bc | 3538 | if (TREE_CONSTANT (t)) |
3539 | /* Don't re-process a constant CONSTRUCTOR, but do fold it to | |
3540 | VECTOR_CST if applicable. */ | |
3541 | return fold (t); | |
1227ba74 | 3542 | r = cxx_eval_bare_aggregate (ctx, t, lval, |
09b42213 | 3543 | non_constant_p, overflow_p); |
3544 | break; | |
3545 | ||
3546 | case VEC_INIT_EXPR: | |
3547 | /* We can get this in a defaulted constructor for a class with a | |
3548 | non-static data member of array type. Either the initializer will | |
3549 | be NULL, meaning default-initialization, or it will be an lvalue | |
3550 | or xvalue of the same type, meaning direct-initialization from the | |
3551 | corresponding member. */ | |
1227ba74 | 3552 | r = cxx_eval_vec_init (ctx, t, lval, |
09b42213 | 3553 | non_constant_p, overflow_p); |
3554 | break; | |
3555 | ||
3556 | case FMA_EXPR: | |
3557 | case VEC_PERM_EXPR: | |
1227ba74 | 3558 | r = cxx_eval_trinary_expression (ctx, t, lval, |
09b42213 | 3559 | non_constant_p, overflow_p); |
3560 | break; | |
3561 | ||
3562 | case CONVERT_EXPR: | |
3563 | case VIEW_CONVERT_EXPR: | |
3564 | case NOP_EXPR: | |
d2c63826 | 3565 | case UNARY_PLUS_EXPR: |
09b42213 | 3566 | { |
d2c63826 | 3567 | enum tree_code tcode = TREE_CODE (t); |
09b42213 | 3568 | tree oldop = TREE_OPERAND (t, 0); |
d2c63826 | 3569 | |
cf72f34d | 3570 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 3571 | lval, |
b2a43197 | 3572 | non_constant_p, overflow_p); |
09b42213 | 3573 | if (*non_constant_p) |
3574 | return t; | |
f16ed232 | 3575 | tree type = TREE_TYPE (t); |
3576 | if (TREE_CODE (op) == PTRMEM_CST | |
3577 | && !TYPE_PTRMEM_P (type)) | |
3578 | op = cplus_expand_constant (op); | |
3579 | if (POINTER_TYPE_P (type) | |
09b42213 | 3580 | && TREE_CODE (op) == INTEGER_CST |
3581 | && !integer_zerop (op)) | |
3582 | { | |
f83e6885 | 3583 | if (!ctx->quiet) |
09b42213 | 3584 | error_at (EXPR_LOC_OR_LOC (t, input_location), |
3585 | "reinterpret_cast from integer to pointer"); | |
3586 | *non_constant_p = true; | |
3587 | return t; | |
3588 | } | |
d2c63826 | 3589 | if (op == oldop && tcode != UNARY_PLUS_EXPR) |
09b42213 | 3590 | /* We didn't fold at the top so we could check for ptr-int |
3591 | conversion. */ | |
3592 | return fold (t); | |
d2c63826 | 3593 | if (tcode == UNARY_PLUS_EXPR) |
3594 | r = fold_convert (TREE_TYPE (t), op); | |
3595 | else | |
3596 | r = fold_build1 (tcode, type, op); | |
09b42213 | 3597 | /* Conversion of an out-of-range value has implementation-defined |
3598 | behavior; the language considers it different from arithmetic | |
3599 | overflow, which is undefined. */ | |
3600 | if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op)) | |
3601 | TREE_OVERFLOW (r) = false; | |
3602 | } | |
3603 | break; | |
3604 | ||
3605 | case EMPTY_CLASS_EXPR: | |
3606 | /* This is good enough for a function argument that might not get | |
3607 | used, and they can't do anything with it, so just return it. */ | |
3608 | return t; | |
3609 | ||
9c96033c | 3610 | case STATEMENT_LIST: |
00f21715 | 3611 | new_ctx = *ctx; |
3612 | new_ctx.ctor = new_ctx.object = NULL_TREE; | |
f83e6885 | 3613 | return cxx_eval_statement_list (&new_ctx, t, |
00f21715 | 3614 | non_constant_p, overflow_p, jump_target); |
9c96033c | 3615 | |
3616 | case BIND_EXPR: | |
3617 | return cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t), | |
1227ba74 | 3618 | lval, |
00f21715 | 3619 | non_constant_p, overflow_p, |
3620 | jump_target); | |
9c96033c | 3621 | |
09b42213 | 3622 | case PREINCREMENT_EXPR: |
3623 | case POSTINCREMENT_EXPR: | |
3624 | case PREDECREMENT_EXPR: | |
3625 | case POSTDECREMENT_EXPR: | |
f83e6885 | 3626 | return cxx_eval_increment_expression (ctx, t, |
1227ba74 | 3627 | lval, non_constant_p, overflow_p); |
9c96033c | 3628 | |
3629 | case LAMBDA_EXPR: | |
09b42213 | 3630 | case NEW_EXPR: |
3631 | case VEC_NEW_EXPR: | |
3632 | case DELETE_EXPR: | |
3633 | case VEC_DELETE_EXPR: | |
3634 | case THROW_EXPR: | |
09b42213 | 3635 | case MODOP_EXPR: |
3636 | /* GCC internal stuff. */ | |
3637 | case VA_ARG_EXPR: | |
3638 | case OBJ_TYPE_REF: | |
3639 | case WITH_CLEANUP_EXPR: | |
09b42213 | 3640 | case NON_DEPENDENT_EXPR: |
3641 | case BASELINK: | |
09b42213 | 3642 | case OFFSET_REF: |
f83e6885 | 3643 | if (!ctx->quiet) |
09b42213 | 3644 | error_at (EXPR_LOC_OR_LOC (t, input_location), |
3645 | "expression %qE is not a constant-expression", t); | |
3646 | *non_constant_p = true; | |
3647 | break; | |
3648 | ||
cf72f34d | 3649 | case PLACEHOLDER_EXPR: |
fe235c02 | 3650 | if (!ctx || !ctx->ctor || (lval && !ctx->object) |
3651 | || !(same_type_ignoring_top_level_qualifiers_p | |
3652 | (TREE_TYPE (t), TREE_TYPE (ctx->ctor)))) | |
cf72f34d | 3653 | { |
3654 | /* A placeholder without a referent. We can get here when | |
3655 | checking whether NSDMIs are noexcept, or in massage_init_elt; | |
3656 | just say it's non-constant for now. */ | |
f83e6885 | 3657 | gcc_assert (ctx->quiet); |
cf72f34d | 3658 | *non_constant_p = true; |
3659 | break; | |
3660 | } | |
3661 | else | |
3662 | { | |
3663 | /* Use of the value or address of the current object. We could | |
3664 | use ctx->object unconditionally, but using ctx->ctor when we | |
3665 | can is a minor optimization. */ | |
1227ba74 | 3666 | tree ctor = lval ? ctx->object : ctx->ctor; |
cf72f34d | 3667 | return cxx_eval_constant_expression |
1227ba74 | 3668 | (ctx, ctor, lval, |
b2a43197 | 3669 | non_constant_p, overflow_p); |
cf72f34d | 3670 | } |
3671 | break; | |
3672 | ||
9c96033c | 3673 | case GOTO_EXPR: |
00f21715 | 3674 | *jump_target = TREE_OPERAND (t, 0); |
3675 | gcc_assert (breaks (jump_target) || continues (jump_target)); | |
3676 | break; | |
3677 | ||
9c96033c | 3678 | case LOOP_EXPR: |
f83e6885 | 3679 | cxx_eval_loop_expr (ctx, t, |
00f21715 | 3680 | non_constant_p, overflow_p, jump_target); |
3681 | break; | |
3682 | ||
9c96033c | 3683 | case SWITCH_EXPR: |
f83e6885 | 3684 | cxx_eval_switch_expr (ctx, t, |
00f21715 | 3685 | non_constant_p, overflow_p, jump_target); |
9c96033c | 3686 | break; |
3687 | ||
56c12fd4 | 3688 | case REQUIRES_EXPR: |
3689 | /* It's possible to get a requires-expression in a constant | |
3690 | expression. For example: | |
3691 | ||
3692 | template<typename T> concept bool C() { | |
3693 | return requires (T t) { t; }; | |
3694 | } | |
3695 | ||
3696 | template<typename T> requires !C<T>() void f(T); | |
3697 | ||
3698 | Normalization leaves f with the associated constraint | |
3699 | '!requires (T t) { ... }' which is not transformed into | |
3700 | a constraint. */ | |
3701 | if (!processing_template_decl) | |
3702 | return evaluate_constraint_expression (t, NULL_TREE); | |
3703 | else | |
3704 | *non_constant_p = true; | |
3705 | return t; | |
3706 | ||
09b42213 | 3707 | default: |
b9a3af23 | 3708 | if (STATEMENT_CODE_P (TREE_CODE (t))) |
3709 | { | |
3710 | /* This function doesn't know how to deal with pre-genericize | |
3711 | statements; this can only happen with statement-expressions, | |
3712 | so for now just fail. */ | |
3713 | if (!ctx->quiet) | |
3714 | error_at (EXPR_LOCATION (t), | |
3715 | "statement is not a constant-expression"); | |
3716 | } | |
3717 | else | |
3718 | internal_error ("unexpected expression %qE of kind %s", t, | |
3719 | get_tree_code_name (TREE_CODE (t))); | |
09b42213 | 3720 | *non_constant_p = true; |
3721 | break; | |
3722 | } | |
3723 | ||
3724 | if (r == error_mark_node) | |
3725 | *non_constant_p = true; | |
3726 | ||
3727 | if (*non_constant_p) | |
3728 | return t; | |
3729 | else | |
3730 | return r; | |
3731 | } | |
3732 | ||
3733 | static tree | |
cf72f34d | 3734 | cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, |
2055d27a | 3735 | bool strict = true, tree object = NULL_TREE) |
09b42213 | 3736 | { |
3737 | bool non_constant_p = false; | |
3738 | bool overflow_p = false; | |
cf72f34d | 3739 | hash_map<tree,tree> map; |
f9885b8a | 3740 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, allow_non_constant, strict }; |
cf72f34d | 3741 | tree type = initialized_type (t); |
cf72f34d | 3742 | tree r = t; |
3743 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) | |
3744 | { | |
3745 | /* In C++14 an NSDMI can participate in aggregate initialization, | |
3746 | and can refer to the address of the object being initialized, so | |
3747 | we need to pass in the relevant VAR_DECL if we want to do the | |
3748 | evaluation in a single pass. The evaluation will dynamically | |
3749 | update ctx.values for the VAR_DECL. We use the same strategy | |
3750 | for C++11 constexpr constructors that refer to the object being | |
3751 | initialized. */ | |
3752 | ctx.ctor = build_constructor (type, NULL); | |
3753 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctx.ctor) = true; | |
9c96033c | 3754 | if (!object) |
3755 | { | |
3756 | if (TREE_CODE (t) == TARGET_EXPR) | |
3757 | object = TARGET_EXPR_SLOT (t); | |
3758 | else if (TREE_CODE (t) == AGGR_INIT_EXPR) | |
3759 | object = AGGR_INIT_EXPR_SLOT (t); | |
3760 | } | |
cf72f34d | 3761 | ctx.object = object; |
3762 | if (object) | |
3763 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
3764 | (type, TREE_TYPE (object))); | |
3765 | if (object && DECL_P (object)) | |
3766 | map.put (object, ctx.ctor); | |
3767 | if (TREE_CODE (r) == TARGET_EXPR) | |
3768 | /* Avoid creating another CONSTRUCTOR when we expand the | |
3769 | TARGET_EXPR. */ | |
3770 | r = TARGET_EXPR_INITIAL (r); | |
3771 | } | |
3772 | ||
f83e6885 | 3773 | r = cxx_eval_constant_expression (&ctx, r, |
b2a43197 | 3774 | false, &non_constant_p, &overflow_p); |
09b42213 | 3775 | |
3776 | verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); | |
3777 | ||
bbcc9042 | 3778 | /* Mutable logic is a bit tricky: we want to allow initialization of |
3779 | constexpr variables with mutable members, but we can't copy those | |
3780 | members to another constexpr variable. */ | |
3781 | if (TREE_CODE (r) == CONSTRUCTOR | |
3782 | && CONSTRUCTOR_MUTABLE_POISON (r)) | |
09b42213 | 3783 | { |
09b42213 | 3784 | if (!allow_non_constant) |
bbcc9042 | 3785 | error ("%qE is not a constant expression because it refers to " |
3786 | "mutable subobjects of %qT", t, type); | |
09b42213 | 3787 | non_constant_p = true; |
3788 | } | |
3789 | ||
3790 | /* Technically we should check this for all subexpressions, but that | |
3791 | runs into problems with our internal representation of pointer | |
3792 | subtraction and the 5.19 rules are still in flux. */ | |
3793 | if (CONVERT_EXPR_CODE_P (TREE_CODE (r)) | |
3794 | && ARITHMETIC_TYPE_P (TREE_TYPE (r)) | |
3795 | && TREE_CODE (TREE_OPERAND (r, 0)) == ADDR_EXPR) | |
3796 | { | |
3797 | if (!allow_non_constant) | |
3798 | error ("conversion from pointer type %qT " | |
3799 | "to arithmetic type %qT in a constant-expression", | |
3800 | TREE_TYPE (TREE_OPERAND (r, 0)), TREE_TYPE (r)); | |
3801 | non_constant_p = true; | |
3802 | } | |
3803 | ||
3804 | if (!non_constant_p && overflow_p) | |
3805 | non_constant_p = true; | |
3806 | ||
3807 | if (non_constant_p && !allow_non_constant) | |
3808 | return error_mark_node; | |
3809 | else if (non_constant_p && TREE_CONSTANT (r)) | |
3810 | { | |
3811 | /* This isn't actually constant, so unset TREE_CONSTANT. */ | |
3812 | if (EXPR_P (r)) | |
3813 | r = copy_node (r); | |
3814 | else if (TREE_CODE (r) == CONSTRUCTOR) | |
3815 | r = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (r), r); | |
3816 | else | |
3817 | r = build_nop (TREE_TYPE (r), r); | |
3818 | TREE_CONSTANT (r) = false; | |
3819 | } | |
3820 | else if (non_constant_p || r == t) | |
3821 | return t; | |
3822 | ||
3823 | if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r))) | |
3824 | { | |
3825 | if (TREE_CODE (t) == TARGET_EXPR | |
3826 | && TARGET_EXPR_INITIAL (t) == r) | |
3827 | return t; | |
3828 | else | |
3829 | { | |
3830 | r = get_target_expr (r); | |
3831 | TREE_CONSTANT (r) = true; | |
3832 | return r; | |
3833 | } | |
3834 | } | |
3835 | else | |
3836 | return r; | |
3837 | } | |
3838 | ||
3839 | /* Returns true if T is a valid subexpression of a constant expression, | |
3840 | even if it isn't itself a constant expression. */ | |
3841 | ||
3842 | bool | |
3843 | is_sub_constant_expr (tree t) | |
3844 | { | |
3845 | bool non_constant_p = false; | |
3846 | bool overflow_p = false; | |
cf72f34d | 3847 | hash_map <tree, tree> map; |
f9885b8a | 3848 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, true, true }; |
f83e6885 | 3849 | cxx_eval_constant_expression (&ctx, t, false, &non_constant_p, |
b2a43197 | 3850 | &overflow_p); |
09b42213 | 3851 | return !non_constant_p && !overflow_p; |
3852 | } | |
3853 | ||
3854 | /* If T represents a constant expression returns its reduced value. | |
3855 | Otherwise return error_mark_node. If T is dependent, then | |
3856 | return NULL. */ | |
3857 | ||
3858 | tree | |
cf72f34d | 3859 | cxx_constant_value (tree t, tree decl) |
09b42213 | 3860 | { |
2055d27a | 3861 | return cxx_eval_outermost_constant_expr (t, false, true, decl); |
09b42213 | 3862 | } |
3863 | ||
d2c63826 | 3864 | /* Helper routine for fold_simple function. Either return simplified |
3865 | expression T, otherwise NULL_TREE. | |
3866 | In contrast to cp_fully_fold, and to maybe_constant_value, we try to fold | |
3867 | even if we are within template-declaration. So be careful on call, as in | |
3868 | such case types can be undefined. */ | |
3869 | ||
3870 | static tree | |
3871 | fold_simple_1 (tree t) | |
3872 | { | |
3873 | tree op1; | |
3874 | enum tree_code code = TREE_CODE (t); | |
3875 | ||
3876 | switch (code) | |
3877 | { | |
3878 | case INTEGER_CST: | |
3879 | case REAL_CST: | |
3880 | case VECTOR_CST: | |
3881 | case FIXED_CST: | |
3882 | case COMPLEX_CST: | |
3883 | return t; | |
3884 | ||
3885 | case SIZEOF_EXPR: | |
3886 | return fold_sizeof_expr (t); | |
3887 | ||
3888 | case ABS_EXPR: | |
3889 | case CONJ_EXPR: | |
3890 | case REALPART_EXPR: | |
3891 | case IMAGPART_EXPR: | |
3892 | case NEGATE_EXPR: | |
3893 | case BIT_NOT_EXPR: | |
3894 | case TRUTH_NOT_EXPR: | |
3895 | case NOP_EXPR: | |
3896 | case VIEW_CONVERT_EXPR: | |
3897 | case CONVERT_EXPR: | |
3898 | case FLOAT_EXPR: | |
3899 | case FIX_TRUNC_EXPR: | |
3900 | case FIXED_CONVERT_EXPR: | |
3901 | case ADDR_SPACE_CONVERT_EXPR: | |
3902 | ||
3903 | op1 = TREE_OPERAND (t, 0); | |
3904 | ||
3905 | t = const_unop (code, TREE_TYPE (t), op1); | |
3906 | if (!t) | |
3907 | return NULL_TREE; | |
3908 | ||
3909 | if (CONVERT_EXPR_CODE_P (code) | |
3910 | && TREE_OVERFLOW_P (t) && !TREE_OVERFLOW_P (op1)) | |
3911 | TREE_OVERFLOW (t) = false; | |
3912 | return t; | |
3913 | ||
3914 | default: | |
3915 | return NULL_TREE; | |
3916 | } | |
3917 | } | |
3918 | ||
3919 | /* If T is a simple constant expression, returns its simplified value. | |
3920 | Otherwise returns T. In contrast to maybe_constant_value do we | |
3921 | simplify only few operations on constant-expressions, and we don't | |
3922 | try to simplify constexpressions. */ | |
3923 | ||
3924 | tree | |
3925 | fold_simple (tree t) | |
3926 | { | |
3927 | tree r = NULL_TREE; | |
3928 | if (processing_template_decl) | |
3929 | return t; | |
3930 | ||
3931 | r = fold_simple_1 (t); | |
3932 | if (!r) | |
3933 | r = t; | |
3934 | ||
3935 | return r; | |
3936 | } | |
3937 | ||
09b42213 | 3938 | /* If T is a constant expression, returns its reduced value. |
3939 | Otherwise, if T does not have TREE_CONSTANT set, returns T. | |
3940 | Otherwise, returns a version of T without TREE_CONSTANT. */ | |
3941 | ||
d2c63826 | 3942 | static tree |
3943 | maybe_constant_value_1 (tree t, tree decl) | |
09b42213 | 3944 | { |
3945 | tree r; | |
3946 | ||
3947 | if (instantiation_dependent_expression_p (t) | |
3948 | || type_unknown_p (t) | |
3949 | || BRACE_ENCLOSED_INITIALIZER_P (t) | |
3950 | || !potential_constant_expression (t)) | |
3951 | { | |
3952 | if (TREE_OVERFLOW_P (t)) | |
3953 | { | |
3954 | t = build_nop (TREE_TYPE (t), t); | |
3955 | TREE_CONSTANT (t) = false; | |
3956 | } | |
3957 | return t; | |
3958 | } | |
3959 | ||
2055d27a | 3960 | r = cxx_eval_outermost_constant_expr (t, true, true, decl); |
5e8689fb | 3961 | gcc_checking_assert (r == t |
3962 | || CONVERT_EXPR_P (t) | |
3963 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
3964 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
3965 | || !cp_tree_equal (r, t)); | |
09b42213 | 3966 | return r; |
3967 | } | |
3968 | ||
d2c63826 | 3969 | static GTY((cache, deletable)) cache_map cv_cache; |
3970 | ||
3971 | /* If T is a constant expression, returns its reduced value. | |
3972 | Otherwise, if T does not have TREE_CONSTANT set, returns T. | |
3973 | Otherwise, returns a version of T without TREE_CONSTANT. */ | |
3974 | ||
3975 | tree | |
3976 | maybe_constant_value (tree t, tree decl) | |
3977 | { | |
3978 | tree ret = cv_cache.get (t); | |
3979 | if (!ret) | |
3980 | { | |
3981 | ret = maybe_constant_value_1 (t, decl); | |
3982 | cv_cache.put (t, ret); | |
3983 | } | |
3984 | return ret; | |
3985 | } | |
3986 | ||
21131a05 | 3987 | /* Like maybe_constant_value but first fully instantiate the argument. |
3988 | ||
3989 | Note: this is equivalent to instantiate_non_dependent_expr_sfinae | |
3990 | (t, tf_none) followed by maybe_constant_value but is more efficient, | |
3991 | because calls instantiation_dependent_expression_p and | |
3992 | potential_constant_expression at most once. */ | |
3993 | ||
3994 | tree | |
3995 | fold_non_dependent_expr (tree t) | |
3996 | { | |
3997 | if (t == NULL_TREE) | |
3998 | return NULL_TREE; | |
3999 | ||
4000 | /* If we're in a template, but T isn't value dependent, simplify | |
4001 | it. We're supposed to treat: | |
4002 | ||
4003 | template <typename T> void f(T[1 + 1]); | |
4004 | template <typename T> void f(T[2]); | |
4005 | ||
4006 | as two declarations of the same function, for example. */ | |
4007 | if (processing_template_decl) | |
4008 | { | |
4009 | if (!instantiation_dependent_expression_p (t) | |
4010 | && potential_constant_expression (t)) | |
4011 | { | |
c8a9f04c | 4012 | processing_template_decl_sentinel s; |
4013 | t = instantiate_non_dependent_expr_internal (t, tf_none); | |
21131a05 | 4014 | |
4015 | if (type_unknown_p (t) | |
4016 | || BRACE_ENCLOSED_INITIALIZER_P (t)) | |
4017 | { | |
4018 | if (TREE_OVERFLOW_P (t)) | |
4019 | { | |
4020 | t = build_nop (TREE_TYPE (t), t); | |
4021 | TREE_CONSTANT (t) = false; | |
4022 | } | |
4023 | return t; | |
4024 | } | |
4025 | ||
2055d27a | 4026 | tree r = cxx_eval_outermost_constant_expr (t, true, true, NULL_TREE); |
21131a05 | 4027 | /* cp_tree_equal looks through NOPs, so allow them. */ |
5e8689fb | 4028 | gcc_checking_assert (r == t |
4029 | || CONVERT_EXPR_P (t) | |
4030 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
4031 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
4032 | || !cp_tree_equal (r, t)); | |
21131a05 | 4033 | return r; |
4034 | } | |
4035 | else if (TREE_OVERFLOW_P (t)) | |
4036 | { | |
4037 | t = build_nop (TREE_TYPE (t), t); | |
4038 | TREE_CONSTANT (t) = false; | |
4039 | } | |
4040 | return t; | |
4041 | } | |
4042 | ||
4043 | return maybe_constant_value (t); | |
4044 | } | |
4045 | ||
09b42213 | 4046 | /* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather |
4047 | than wrapped in a TARGET_EXPR. */ | |
4048 | ||
4049 | tree | |
cf72f34d | 4050 | maybe_constant_init (tree t, tree decl) |
09b42213 | 4051 | { |
d2c63826 | 4052 | if (!t) |
4053 | return t; | |
09b42213 | 4054 | if (TREE_CODE (t) == EXPR_STMT) |
4055 | t = TREE_OPERAND (t, 0); | |
4056 | if (TREE_CODE (t) == CONVERT_EXPR | |
4057 | && VOID_TYPE_P (TREE_TYPE (t))) | |
4058 | t = TREE_OPERAND (t, 0); | |
9c96033c | 4059 | if (TREE_CODE (t) == INIT_EXPR) |
4060 | t = TREE_OPERAND (t, 1); | |
2055d27a | 4061 | if (instantiation_dependent_expression_p (t) |
4062 | || type_unknown_p (t) | |
4063 | || BRACE_ENCLOSED_INITIALIZER_P (t) | |
4064 | || !potential_static_init_expression (t)) | |
4065 | /* Don't try to evaluate it. */; | |
4066 | else | |
4067 | t = cxx_eval_outermost_constant_expr (t, true, false, decl); | |
09b42213 | 4068 | if (TREE_CODE (t) == TARGET_EXPR) |
4069 | { | |
4070 | tree init = TARGET_EXPR_INITIAL (t); | |
4071 | if (TREE_CODE (init) == CONSTRUCTOR) | |
4072 | t = init; | |
4073 | } | |
4074 | return t; | |
4075 | } | |
4076 | ||
4077 | #if 0 | |
4078 | /* FIXME see ADDR_EXPR section in potential_constant_expression_1. */ | |
4079 | /* Return true if the object referred to by REF has automatic or thread | |
4080 | local storage. */ | |
4081 | ||
4082 | enum { ck_ok, ck_bad, ck_unknown }; | |
4083 | static int | |
4084 | check_automatic_or_tls (tree ref) | |
4085 | { | |
3754d046 | 4086 | machine_mode mode; |
09b42213 | 4087 | HOST_WIDE_INT bitsize, bitpos; |
4088 | tree offset; | |
4089 | int volatilep = 0, unsignedp = 0; | |
4090 | tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset, | |
4091 | &mode, &unsignedp, &volatilep, false); | |
4092 | duration_kind dk; | |
4093 | ||
4094 | /* If there isn't a decl in the middle, we don't know the linkage here, | |
4095 | and this isn't a constant expression anyway. */ | |
4096 | if (!DECL_P (decl)) | |
4097 | return ck_unknown; | |
4098 | dk = decl_storage_duration (decl); | |
4099 | return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok; | |
4100 | } | |
4101 | #endif | |
4102 | ||
4103 | /* Return true if T denotes a potentially constant expression. Issue | |
4104 | diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true, | |
4105 | an lvalue-rvalue conversion is implied. | |
4106 | ||
4107 | C++0x [expr.const] used to say | |
4108 | ||
4109 | 6 An expression is a potential constant expression if it is | |
4110 | a constant expression where all occurrences of function | |
4111 | parameters are replaced by arbitrary constant expressions | |
4112 | of the appropriate type. | |
4113 | ||
4114 | 2 A conditional expression is a constant expression unless it | |
4115 | involves one of the following as a potentially evaluated | |
4116 | subexpression (3.2), but subexpressions of logical AND (5.14), | |
4117 | logical OR (5.15), and conditional (5.16) operations that are | |
4118 | not evaluated are not considered. */ | |
4119 | ||
4120 | static bool | |
2055d27a | 4121 | potential_constant_expression_1 (tree t, bool want_rval, bool strict, |
4122 | tsubst_flags_t flags) | |
09b42213 | 4123 | { |
2055d27a | 4124 | #define RECUR(T,RV) potential_constant_expression_1 ((T), (RV), strict, flags) |
09b42213 | 4125 | enum { any = false, rval = true }; |
4126 | int i; | |
4127 | tree tmp; | |
4128 | ||
4129 | if (t == error_mark_node) | |
4130 | return false; | |
4131 | if (t == NULL_TREE) | |
4132 | return true; | |
eade0940 | 4133 | if (TREE_THIS_VOLATILE (t) && !DECL_P (t)) |
09b42213 | 4134 | { |
4135 | if (flags & tf_error) | |
4136 | error ("expression %qE has side-effects", t); | |
4137 | return false; | |
4138 | } | |
4139 | if (CONSTANT_CLASS_P (t)) | |
4140 | return true; | |
4141 | ||
4142 | switch (TREE_CODE (t)) | |
4143 | { | |
4144 | case FUNCTION_DECL: | |
4145 | case BASELINK: | |
4146 | case TEMPLATE_DECL: | |
4147 | case OVERLOAD: | |
4148 | case TEMPLATE_ID_EXPR: | |
4149 | case LABEL_DECL: | |
4150 | case LABEL_EXPR: | |
9c96033c | 4151 | case CASE_LABEL_EXPR: |
09b42213 | 4152 | case CONST_DECL: |
4153 | case SIZEOF_EXPR: | |
4154 | case ALIGNOF_EXPR: | |
4155 | case OFFSETOF_EXPR: | |
4156 | case NOEXCEPT_EXPR: | |
4157 | case TEMPLATE_PARM_INDEX: | |
4158 | case TRAIT_EXPR: | |
4159 | case IDENTIFIER_NODE: | |
4160 | case USERDEF_LITERAL: | |
4161 | /* We can see a FIELD_DECL in a pointer-to-member expression. */ | |
4162 | case FIELD_DECL: | |
4163 | case PARM_DECL: | |
d2c63826 | 4164 | case RESULT_DECL: |
09b42213 | 4165 | case USING_DECL: |
9c96033c | 4166 | case USING_STMT: |
cf72f34d | 4167 | case PLACEHOLDER_EXPR: |
9c96033c | 4168 | case BREAK_STMT: |
4169 | case CONTINUE_STMT: | |
56c12fd4 | 4170 | case REQUIRES_EXPR: |
09b42213 | 4171 | return true; |
4172 | ||
4173 | case AGGR_INIT_EXPR: | |
4174 | case CALL_EXPR: | |
4175 | /* -- an invocation of a function other than a constexpr function | |
4176 | or a constexpr constructor. */ | |
4177 | { | |
4178 | tree fun = get_function_named_in_call (t); | |
4179 | const int nargs = call_expr_nargs (t); | |
4180 | i = 0; | |
4181 | ||
9c96033c | 4182 | if (fun == NULL_TREE) |
4183 | { | |
32cf7025 | 4184 | if (TREE_CODE (t) == CALL_EXPR |
4185 | && CALL_EXPR_FN (t) == NULL_TREE) | |
4186 | switch (CALL_EXPR_IFN (t)) | |
4187 | { | |
4188 | /* These should be ignored, they are optimized away from | |
4189 | constexpr functions. */ | |
4190 | case IFN_UBSAN_NULL: | |
4191 | case IFN_UBSAN_BOUNDS: | |
4192 | case IFN_UBSAN_VPTR: | |
4193 | return true; | |
4194 | default: | |
4195 | break; | |
4196 | } | |
9c96033c | 4197 | /* fold_call_expr can't do anything with IFN calls. */ |
4198 | if (flags & tf_error) | |
4199 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4200 | "call to internal function"); | |
4201 | return false; | |
4202 | } | |
09b42213 | 4203 | if (is_overloaded_fn (fun)) |
4204 | { | |
4205 | if (TREE_CODE (fun) == FUNCTION_DECL) | |
4206 | { | |
4207 | if (builtin_valid_in_constant_expr_p (fun)) | |
4208 | return true; | |
4209 | if (!DECL_DECLARED_CONSTEXPR_P (fun) | |
4210 | /* Allow any built-in function; if the expansion | |
4211 | isn't constant, we'll deal with that then. */ | |
4212 | && !is_builtin_fn (fun)) | |
4213 | { | |
4214 | if (flags & tf_error) | |
4215 | { | |
4216 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4217 | "call to non-constexpr function %qD", fun); | |
4218 | explain_invalid_constexpr_fn (fun); | |
4219 | } | |
4220 | return false; | |
4221 | } | |
4222 | /* A call to a non-static member function takes the address | |
4223 | of the object as the first argument. But in a constant | |
4224 | expression the address will be folded away, so look | |
4225 | through it now. */ | |
4226 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
4227 | && !DECL_CONSTRUCTOR_P (fun)) | |
4228 | { | |
4229 | tree x = get_nth_callarg (t, 0); | |
4230 | if (is_this_parameter (x)) | |
cf72f34d | 4231 | return true; |
2055d27a | 4232 | else if (!RECUR (x, rval)) |
09b42213 | 4233 | return false; |
4234 | i = 1; | |
4235 | } | |
4236 | } | |
4237 | else | |
4238 | { | |
2055d27a | 4239 | if (!RECUR (fun, true)) |
09b42213 | 4240 | return false; |
4241 | fun = get_first_fn (fun); | |
4242 | } | |
4243 | /* Skip initial arguments to base constructors. */ | |
4244 | if (DECL_BASE_CONSTRUCTOR_P (fun)) | |
4245 | i = num_artificial_parms_for (fun); | |
4246 | fun = DECL_ORIGIN (fun); | |
4247 | } | |
4248 | else | |
4249 | { | |
2055d27a | 4250 | if (RECUR (fun, rval)) |
09b42213 | 4251 | /* Might end up being a constant function pointer. */; |
4252 | else | |
4253 | return false; | |
4254 | } | |
4255 | for (; i < nargs; ++i) | |
4256 | { | |
4257 | tree x = get_nth_callarg (t, i); | |
b2742b58 | 4258 | /* In a template, reference arguments haven't been converted to |
4259 | REFERENCE_TYPE and we might not even know if the parameter | |
4260 | is a reference, so accept lvalue constants too. */ | |
4261 | bool rv = processing_template_decl ? any : rval; | |
4262 | if (!RECUR (x, rv)) | |
09b42213 | 4263 | return false; |
4264 | } | |
4265 | return true; | |
4266 | } | |
4267 | ||
4268 | case NON_LVALUE_EXPR: | |
4269 | /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to | |
4270 | -- an lvalue of integral type that refers to a non-volatile | |
4271 | const variable or static data member initialized with | |
4272 | constant expressions, or | |
4273 | ||
4274 | -- an lvalue of literal type that refers to non-volatile | |
4275 | object defined with constexpr, or that refers to a | |
4276 | sub-object of such an object; */ | |
2055d27a | 4277 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 4278 | |
4279 | case VAR_DECL: | |
2055d27a | 4280 | if (want_rval |
4281 | && !decl_constant_var_p (t) | |
4282 | && (strict | |
4283 | || !CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (t)) | |
4284 | || !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (t)) | |
09b42213 | 4285 | && !var_in_constexpr_fn (t) |
dff5042c | 4286 | && !type_dependent_expression_p (t)) |
09b42213 | 4287 | { |
4288 | if (flags & tf_error) | |
4289 | non_const_var_error (t); | |
4290 | return false; | |
4291 | } | |
4292 | return true; | |
4293 | ||
4294 | case NOP_EXPR: | |
4295 | case CONVERT_EXPR: | |
4296 | case VIEW_CONVERT_EXPR: | |
4297 | /* -- a reinterpret_cast. FIXME not implemented, and this rule | |
4298 | may change to something more specific to type-punning (DR 1312). */ | |
4299 | { | |
4300 | tree from = TREE_OPERAND (t, 0); | |
4301 | if (POINTER_TYPE_P (TREE_TYPE (t)) | |
4302 | && TREE_CODE (from) == INTEGER_CST | |
4303 | && !integer_zerop (from)) | |
4304 | { | |
4305 | if (flags & tf_error) | |
4306 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4307 | "reinterpret_cast from integer to pointer"); | |
4308 | return false; | |
4309 | } | |
2055d27a | 4310 | return (RECUR (from, TREE_CODE (t) != VIEW_CONVERT_EXPR)); |
09b42213 | 4311 | } |
4312 | ||
4313 | case ADDR_EXPR: | |
4314 | /* -- a unary operator & that is applied to an lvalue that | |
4315 | designates an object with thread or automatic storage | |
4316 | duration; */ | |
4317 | t = TREE_OPERAND (t, 0); | |
4318 | ||
4319 | if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t)) | |
4320 | /* A pointer-to-member constant. */ | |
4321 | return true; | |
4322 | ||
4323 | #if 0 | |
4324 | /* FIXME adjust when issue 1197 is fully resolved. For now don't do | |
4325 | any checking here, as we might dereference the pointer later. If | |
4326 | we remove this code, also remove check_automatic_or_tls. */ | |
4327 | i = check_automatic_or_tls (t); | |
4328 | if (i == ck_ok) | |
4329 | return true; | |
4330 | if (i == ck_bad) | |
4331 | { | |
4332 | if (flags & tf_error) | |
4333 | error ("address-of an object %qE with thread local or " | |
4334 | "automatic storage is not a constant expression", t); | |
4335 | return false; | |
4336 | } | |
4337 | #endif | |
2055d27a | 4338 | return RECUR (t, any); |
09b42213 | 4339 | |
4340 | case COMPONENT_REF: | |
4341 | case BIT_FIELD_REF: | |
4342 | case ARROW_EXPR: | |
4343 | case OFFSET_REF: | |
4344 | /* -- a class member access unless its postfix-expression is | |
4345 | of literal type or of pointer to literal type. */ | |
4346 | /* This test would be redundant, as it follows from the | |
4347 | postfix-expression being a potential constant expression. */ | |
eade0940 | 4348 | if (type_unknown_p (t)) |
4349 | return true; | |
2055d27a | 4350 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 4351 | |
4352 | case EXPR_PACK_EXPANSION: | |
2055d27a | 4353 | return RECUR (PACK_EXPANSION_PATTERN (t), want_rval); |
09b42213 | 4354 | |
4355 | case INDIRECT_REF: | |
4356 | { | |
4357 | tree x = TREE_OPERAND (t, 0); | |
4358 | STRIP_NOPS (x); | |
4359 | if (is_this_parameter (x)) | |
4360 | { | |
4361 | if (DECL_CONTEXT (x) | |
4362 | && !DECL_DECLARED_CONSTEXPR_P (DECL_CONTEXT (x))) | |
4363 | { | |
4364 | if (flags & tf_error) | |
4365 | error ("use of %<this%> in a constant expression"); | |
4366 | return false; | |
4367 | } | |
09b42213 | 4368 | return true; |
4369 | } | |
2055d27a | 4370 | return RECUR (x, rval); |
09b42213 | 4371 | } |
4372 | ||
9c96033c | 4373 | case STATEMENT_LIST: |
4374 | { | |
4375 | tree_stmt_iterator i; | |
4376 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
4377 | { | |
2055d27a | 4378 | if (!RECUR (tsi_stmt (i), any)) |
9c96033c | 4379 | return false; |
4380 | } | |
4381 | return true; | |
4382 | } | |
4383 | break; | |
4384 | ||
4385 | case MODIFY_EXPR: | |
4386 | if (cxx_dialect < cxx14) | |
4387 | goto fail; | |
2055d27a | 4388 | if (!RECUR (TREE_OPERAND (t, 0), any)) |
9c96033c | 4389 | return false; |
2055d27a | 4390 | if (!RECUR (TREE_OPERAND (t, 1), rval)) |
9c96033c | 4391 | return false; |
4392 | return true; | |
4393 | ||
4394 | case MODOP_EXPR: | |
4395 | if (cxx_dialect < cxx14) | |
4396 | goto fail; | |
2055d27a | 4397 | if (!RECUR (TREE_OPERAND (t, 0), rval)) |
9c96033c | 4398 | return false; |
2055d27a | 4399 | if (!RECUR (TREE_OPERAND (t, 2), rval)) |
9c96033c | 4400 | return false; |
4401 | return true; | |
4402 | ||
9c96033c | 4403 | case DO_STMT: |
2055d27a | 4404 | if (!RECUR (DO_COND (t), rval)) |
9c96033c | 4405 | return false; |
2055d27a | 4406 | if (!RECUR (DO_BODY (t), any)) |
9c96033c | 4407 | return false; |
4408 | return true; | |
4409 | ||
4410 | case FOR_STMT: | |
2055d27a | 4411 | if (!RECUR (FOR_INIT_STMT (t), any)) |
9c96033c | 4412 | return false; |
2055d27a | 4413 | if (!RECUR (FOR_COND (t), rval)) |
9c96033c | 4414 | return false; |
2055d27a | 4415 | if (!RECUR (FOR_EXPR (t), any)) |
9c96033c | 4416 | return false; |
2055d27a | 4417 | if (!RECUR (FOR_BODY (t), any)) |
9c96033c | 4418 | return false; |
4419 | return true; | |
4420 | ||
4421 | case WHILE_STMT: | |
2055d27a | 4422 | if (!RECUR (WHILE_COND (t), rval)) |
9c96033c | 4423 | return false; |
2055d27a | 4424 | if (!RECUR (WHILE_BODY (t), any)) |
9c96033c | 4425 | return false; |
4426 | return true; | |
4427 | ||
4428 | case SWITCH_STMT: | |
2055d27a | 4429 | if (!RECUR (SWITCH_STMT_COND (t), rval)) |
9c96033c | 4430 | return false; |
748c426a | 4431 | /* FIXME we don't check SWITCH_STMT_BODY currently, because even |
4432 | unreachable labels would be checked. */ | |
9c96033c | 4433 | return true; |
4434 | ||
da7981e0 | 4435 | case STMT_EXPR: |
2055d27a | 4436 | return RECUR (STMT_EXPR_STMT (t), rval); |
da7981e0 | 4437 | |
09b42213 | 4438 | case LAMBDA_EXPR: |
4439 | case DYNAMIC_CAST_EXPR: | |
4440 | case PSEUDO_DTOR_EXPR: | |
09b42213 | 4441 | case NEW_EXPR: |
4442 | case VEC_NEW_EXPR: | |
4443 | case DELETE_EXPR: | |
4444 | case VEC_DELETE_EXPR: | |
4445 | case THROW_EXPR: | |
09b42213 | 4446 | case OMP_ATOMIC: |
4447 | case OMP_ATOMIC_READ: | |
4448 | case OMP_ATOMIC_CAPTURE_OLD: | |
4449 | case OMP_ATOMIC_CAPTURE_NEW: | |
4450 | /* GCC internal stuff. */ | |
4451 | case VA_ARG_EXPR: | |
4452 | case OBJ_TYPE_REF: | |
09b42213 | 4453 | case TRANSACTION_EXPR: |
9c96033c | 4454 | case ASM_EXPR: |
9abecca2 | 4455 | case AT_ENCODE_EXPR: |
9c96033c | 4456 | fail: |
09b42213 | 4457 | if (flags & tf_error) |
4458 | error ("expression %qE is not a constant-expression", t); | |
4459 | return false; | |
4460 | ||
4461 | case TYPEID_EXPR: | |
4462 | /* -- a typeid expression whose operand is of polymorphic | |
4463 | class type; */ | |
4464 | { | |
4465 | tree e = TREE_OPERAND (t, 0); | |
4466 | if (!TYPE_P (e) && !type_dependent_expression_p (e) | |
4467 | && TYPE_POLYMORPHIC_P (TREE_TYPE (e))) | |
4468 | { | |
4469 | if (flags & tf_error) | |
4470 | error ("typeid-expression is not a constant expression " | |
4471 | "because %qE is of polymorphic type", e); | |
4472 | return false; | |
4473 | } | |
4474 | return true; | |
4475 | } | |
4476 | ||
4477 | case MINUS_EXPR: | |
09b42213 | 4478 | want_rval = true; |
4479 | goto binary; | |
4480 | ||
4481 | case LT_EXPR: | |
4482 | case LE_EXPR: | |
4483 | case GT_EXPR: | |
4484 | case GE_EXPR: | |
4485 | case EQ_EXPR: | |
4486 | case NE_EXPR: | |
09b42213 | 4487 | want_rval = true; |
4488 | goto binary; | |
4489 | ||
9c96033c | 4490 | case PREINCREMENT_EXPR: |
4491 | case POSTINCREMENT_EXPR: | |
4492 | case PREDECREMENT_EXPR: | |
4493 | case POSTDECREMENT_EXPR: | |
4494 | if (cxx_dialect < cxx14) | |
4495 | goto fail; | |
4496 | goto unary; | |
4497 | ||
09b42213 | 4498 | case BIT_NOT_EXPR: |
4499 | /* A destructor. */ | |
4500 | if (TYPE_P (TREE_OPERAND (t, 0))) | |
4501 | return true; | |
4502 | /* else fall through. */ | |
4503 | ||
4504 | case REALPART_EXPR: | |
4505 | case IMAGPART_EXPR: | |
4506 | case CONJ_EXPR: | |
4507 | case SAVE_EXPR: | |
4508 | case FIX_TRUNC_EXPR: | |
4509 | case FLOAT_EXPR: | |
4510 | case NEGATE_EXPR: | |
4511 | case ABS_EXPR: | |
4512 | case TRUTH_NOT_EXPR: | |
4513 | case FIXED_CONVERT_EXPR: | |
4514 | case UNARY_PLUS_EXPR: | |
6fdf70f5 | 4515 | case UNARY_LEFT_FOLD_EXPR: |
4516 | case UNARY_RIGHT_FOLD_EXPR: | |
9c96033c | 4517 | unary: |
2055d27a | 4518 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 4519 | |
4520 | case CAST_EXPR: | |
4521 | case CONST_CAST_EXPR: | |
4522 | case STATIC_CAST_EXPR: | |
4523 | case REINTERPRET_CAST_EXPR: | |
4524 | case IMPLICIT_CONV_EXPR: | |
4525 | if (cxx_dialect < cxx11 | |
4526 | && !dependent_type_p (TREE_TYPE (t)) | |
4527 | && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t))) | |
4528 | /* In C++98, a conversion to non-integral type can't be part of a | |
4529 | constant expression. */ | |
4530 | { | |
4531 | if (flags & tf_error) | |
4532 | error ("cast to non-integral type %qT in a constant expression", | |
4533 | TREE_TYPE (t)); | |
4534 | return false; | |
4535 | } | |
4536 | ||
2055d27a | 4537 | return (RECUR (TREE_OPERAND (t, 0), |
4538 | TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE)); | |
09b42213 | 4539 | |
9c96033c | 4540 | case BIND_EXPR: |
2055d27a | 4541 | return RECUR (BIND_EXPR_BODY (t), want_rval); |
9c96033c | 4542 | |
4543 | case WITH_CLEANUP_EXPR: | |
4544 | case CLEANUP_POINT_EXPR: | |
4545 | case MUST_NOT_THROW_EXPR: | |
4546 | case TRY_CATCH_EXPR: | |
7f67d68c | 4547 | case TRY_BLOCK: |
9c96033c | 4548 | case EH_SPEC_BLOCK: |
4549 | case EXPR_STMT: | |
09b42213 | 4550 | case PAREN_EXPR: |
9c96033c | 4551 | case DECL_EXPR: |
09b42213 | 4552 | case NON_DEPENDENT_EXPR: |
4553 | /* For convenience. */ | |
4554 | case RETURN_EXPR: | |
2055d27a | 4555 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 4556 | |
7f67d68c | 4557 | case TRY_FINALLY_EXPR: |
4558 | return (RECUR (TREE_OPERAND (t, 0), want_rval) | |
4559 | && RECUR (TREE_OPERAND (t, 1), any)); | |
4560 | ||
09b42213 | 4561 | case SCOPE_REF: |
2055d27a | 4562 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 4563 | |
4564 | case TARGET_EXPR: | |
4565 | if (!literal_type_p (TREE_TYPE (t))) | |
4566 | { | |
4567 | if (flags & tf_error) | |
4568 | { | |
4569 | error ("temporary of non-literal type %qT in a " | |
4570 | "constant expression", TREE_TYPE (t)); | |
4571 | explain_non_literal_class (TREE_TYPE (t)); | |
4572 | } | |
4573 | return false; | |
4574 | } | |
4575 | case INIT_EXPR: | |
2055d27a | 4576 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 4577 | |
4578 | case CONSTRUCTOR: | |
4579 | { | |
4580 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
4581 | constructor_elt *ce; | |
4582 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2055d27a | 4583 | if (!RECUR (ce->value, want_rval)) |
09b42213 | 4584 | return false; |
4585 | return true; | |
4586 | } | |
4587 | ||
4588 | case TREE_LIST: | |
4589 | { | |
4590 | gcc_assert (TREE_PURPOSE (t) == NULL_TREE | |
4591 | || DECL_P (TREE_PURPOSE (t))); | |
2055d27a | 4592 | if (!RECUR (TREE_VALUE (t), want_rval)) |
09b42213 | 4593 | return false; |
4594 | if (TREE_CHAIN (t) == NULL_TREE) | |
4595 | return true; | |
2055d27a | 4596 | return RECUR (TREE_CHAIN (t), want_rval); |
09b42213 | 4597 | } |
4598 | ||
4599 | case TRUNC_DIV_EXPR: | |
4600 | case CEIL_DIV_EXPR: | |
4601 | case FLOOR_DIV_EXPR: | |
4602 | case ROUND_DIV_EXPR: | |
4603 | case TRUNC_MOD_EXPR: | |
4604 | case CEIL_MOD_EXPR: | |
4605 | case ROUND_MOD_EXPR: | |
4606 | { | |
4607 | tree denom = TREE_OPERAND (t, 1); | |
2055d27a | 4608 | if (!RECUR (denom, rval)) |
09b42213 | 4609 | return false; |
4610 | /* We can't call cxx_eval_outermost_constant_expr on an expression | |
21131a05 | 4611 | that hasn't been through instantiate_non_dependent_expr yet. */ |
09b42213 | 4612 | if (!processing_template_decl) |
4613 | denom = cxx_eval_outermost_constant_expr (denom, true); | |
4614 | if (integer_zerop (denom)) | |
4615 | { | |
4616 | if (flags & tf_error) | |
4617 | error ("division by zero is not a constant-expression"); | |
4618 | return false; | |
4619 | } | |
4620 | else | |
4621 | { | |
4622 | want_rval = true; | |
2055d27a | 4623 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 4624 | } |
4625 | } | |
4626 | ||
4627 | case COMPOUND_EXPR: | |
4628 | { | |
4629 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
4630 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
4631 | introduced by build_call_a. */ | |
4632 | tree op0 = TREE_OPERAND (t, 0); | |
4633 | tree op1 = TREE_OPERAND (t, 1); | |
4634 | STRIP_NOPS (op1); | |
4635 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
4636 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
2055d27a | 4637 | return RECUR (op0, want_rval); |
09b42213 | 4638 | else |
4639 | goto binary; | |
4640 | } | |
4641 | ||
4642 | /* If the first operand is the non-short-circuit constant, look at | |
4643 | the second operand; otherwise we only care about the first one for | |
4644 | potentiality. */ | |
4645 | case TRUTH_AND_EXPR: | |
4646 | case TRUTH_ANDIF_EXPR: | |
4647 | tmp = boolean_true_node; | |
4648 | goto truth; | |
4649 | case TRUTH_OR_EXPR: | |
4650 | case TRUTH_ORIF_EXPR: | |
4651 | tmp = boolean_false_node; | |
4652 | truth: | |
4653 | { | |
4654 | tree op = TREE_OPERAND (t, 0); | |
2055d27a | 4655 | if (!RECUR (op, rval)) |
09b42213 | 4656 | return false; |
4657 | if (!processing_template_decl) | |
4658 | op = cxx_eval_outermost_constant_expr (op, true); | |
4659 | if (tree_int_cst_equal (op, tmp)) | |
2055d27a | 4660 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 4661 | else |
4662 | return true; | |
4663 | } | |
4664 | ||
4665 | case PLUS_EXPR: | |
4666 | case MULT_EXPR: | |
4667 | case POINTER_PLUS_EXPR: | |
4668 | case RDIV_EXPR: | |
4669 | case EXACT_DIV_EXPR: | |
4670 | case MIN_EXPR: | |
4671 | case MAX_EXPR: | |
4672 | case LSHIFT_EXPR: | |
4673 | case RSHIFT_EXPR: | |
4674 | case LROTATE_EXPR: | |
4675 | case RROTATE_EXPR: | |
4676 | case BIT_IOR_EXPR: | |
4677 | case BIT_XOR_EXPR: | |
4678 | case BIT_AND_EXPR: | |
4679 | case TRUTH_XOR_EXPR: | |
4680 | case UNORDERED_EXPR: | |
4681 | case ORDERED_EXPR: | |
4682 | case UNLT_EXPR: | |
4683 | case UNLE_EXPR: | |
4684 | case UNGT_EXPR: | |
4685 | case UNGE_EXPR: | |
4686 | case UNEQ_EXPR: | |
4687 | case LTGT_EXPR: | |
4688 | case RANGE_EXPR: | |
4689 | case COMPLEX_EXPR: | |
4690 | want_rval = true; | |
4691 | /* Fall through. */ | |
4692 | case ARRAY_REF: | |
4693 | case ARRAY_RANGE_REF: | |
4694 | case MEMBER_REF: | |
4695 | case DOTSTAR_EXPR: | |
f0abe78f | 4696 | case MEM_REF: |
6fdf70f5 | 4697 | case BINARY_LEFT_FOLD_EXPR: |
4698 | case BINARY_RIGHT_FOLD_EXPR: | |
09b42213 | 4699 | binary: |
4700 | for (i = 0; i < 2; ++i) | |
2055d27a | 4701 | if (!RECUR (TREE_OPERAND (t, i), want_rval)) |
09b42213 | 4702 | return false; |
4703 | return true; | |
4704 | ||
4705 | case CILK_SYNC_STMT: | |
4706 | case CILK_SPAWN_STMT: | |
4707 | case ARRAY_NOTATION_REF: | |
4708 | return false; | |
4709 | ||
4710 | case FMA_EXPR: | |
4711 | case VEC_PERM_EXPR: | |
4712 | for (i = 0; i < 3; ++i) | |
2055d27a | 4713 | if (!RECUR (TREE_OPERAND (t, i), true)) |
09b42213 | 4714 | return false; |
4715 | return true; | |
4716 | ||
748c426a | 4717 | case IF_STMT: |
09b42213 | 4718 | case COND_EXPR: |
4719 | case VEC_COND_EXPR: | |
4720 | /* If the condition is a known constant, we know which of the legs we | |
4721 | care about; otherwise we only require that the condition and | |
4722 | either of the legs be potentially constant. */ | |
4723 | tmp = TREE_OPERAND (t, 0); | |
2055d27a | 4724 | if (!RECUR (tmp, rval)) |
09b42213 | 4725 | return false; |
4726 | if (!processing_template_decl) | |
4727 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
4728 | if (integer_zerop (tmp)) | |
2055d27a | 4729 | return RECUR (TREE_OPERAND (t, 2), want_rval); |
09b42213 | 4730 | else if (TREE_CODE (tmp) == INTEGER_CST) |
2055d27a | 4731 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 4732 | for (i = 1; i < 3; ++i) |
4733 | if (potential_constant_expression_1 (TREE_OPERAND (t, i), | |
2055d27a | 4734 | want_rval, strict, tf_none)) |
09b42213 | 4735 | return true; |
4736 | if (flags & tf_error) | |
4737 | error ("expression %qE is not a constant-expression", t); | |
4738 | return false; | |
4739 | ||
4740 | case VEC_INIT_EXPR: | |
4741 | if (VEC_INIT_EXPR_IS_CONSTEXPR (t)) | |
4742 | return true; | |
4743 | if (flags & tf_error) | |
4744 | { | |
4745 | error ("non-constant array initialization"); | |
4746 | diagnose_non_constexpr_vec_init (t); | |
4747 | } | |
4748 | return false; | |
4749 | ||
db1ae94f | 4750 | case TYPE_DECL: |
4751 | case TAG_DEFN: | |
4752 | /* We can see these in statement-expressions. */ | |
4753 | return true; | |
4754 | ||
d2c63826 | 4755 | case EMPTY_CLASS_EXPR: |
4756 | return false; | |
4757 | ||
09b42213 | 4758 | default: |
4759 | if (objc_is_property_ref (t)) | |
4760 | return false; | |
4761 | ||
4762 | sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t))); | |
4763 | gcc_unreachable(); | |
4764 | return false; | |
4765 | } | |
2055d27a | 4766 | #undef RECUR |
09b42213 | 4767 | } |
4768 | ||
4769 | /* The main entry point to the above. */ | |
4770 | ||
4771 | bool | |
4772 | potential_constant_expression (tree t) | |
4773 | { | |
2055d27a | 4774 | return potential_constant_expression_1 (t, false, true, tf_none); |
4775 | } | |
4776 | ||
4777 | bool | |
4778 | potential_static_init_expression (tree t) | |
4779 | { | |
4780 | return potential_constant_expression_1 (t, false, false, tf_none); | |
09b42213 | 4781 | } |
4782 | ||
4783 | /* As above, but require a constant rvalue. */ | |
4784 | ||
4785 | bool | |
4786 | potential_rvalue_constant_expression (tree t) | |
4787 | { | |
2055d27a | 4788 | return potential_constant_expression_1 (t, true, true, tf_none); |
09b42213 | 4789 | } |
4790 | ||
4791 | /* Like above, but complain about non-constant expressions. */ | |
4792 | ||
4793 | bool | |
4794 | require_potential_constant_expression (tree t) | |
4795 | { | |
2055d27a | 4796 | return potential_constant_expression_1 (t, false, true, tf_warning_or_error); |
09b42213 | 4797 | } |
4798 | ||
4799 | /* Cross product of the above. */ | |
4800 | ||
4801 | bool | |
4802 | require_potential_rvalue_constant_expression (tree t) | |
4803 | { | |
2055d27a | 4804 | return potential_constant_expression_1 (t, true, true, tf_warning_or_error); |
09b42213 | 4805 | } |
4806 | ||
4807 | #include "gt-cp-constexpr.h" |