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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 | ||
d353bf18 | 5 | Copyright (C) 1998-2015 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" | |
b20a8bb4 | 26 | #include "input.h" |
27 | #include "alias.h" | |
28 | #include "symtab.h" | |
29 | #include "options.h" | |
09b42213 | 30 | #include "tree.h" |
31 | #include "varasm.h" | |
32 | #include "cp-tree.h" | |
33 | #include "c-family/c-objc.h" | |
34 | #include "tree-iterator.h" | |
35 | #include "gimplify.h" | |
36 | #include "builtins.h" | |
9c96033c | 37 | #include "tree-inline.h" |
6b71bdb4 | 38 | #include "ubsan.h" |
09b42213 | 39 | |
40 | static bool verify_constant (tree, bool, bool *, bool *); | |
41 | #define VERIFY_CONSTANT(X) \ | |
42 | do { \ | |
f83e6885 | 43 | if (verify_constant ((X), ctx->quiet, non_constant_p, overflow_p)) \ |
09b42213 | 44 | return t; \ |
45 | } while (0) | |
46 | ||
47 | /* Returns true iff FUN is an instantiation of a constexpr function | |
48 | template or a defaulted constexpr function. */ | |
49 | ||
50 | bool | |
51 | is_instantiation_of_constexpr (tree fun) | |
52 | { | |
53 | return ((DECL_TEMPLOID_INSTANTIATION (fun) | |
54 | && DECL_DECLARED_CONSTEXPR_P (DECL_TI_TEMPLATE (fun))) | |
55 | || (DECL_DEFAULTED_FN (fun) | |
56 | && DECL_DECLARED_CONSTEXPR_P (fun))); | |
57 | } | |
58 | ||
59 | /* Return true if T is a literal type. */ | |
60 | ||
61 | bool | |
62 | literal_type_p (tree t) | |
63 | { | |
64 | if (SCALAR_TYPE_P (t) | |
65 | || TREE_CODE (t) == VECTOR_TYPE | |
dd418b39 | 66 | || TREE_CODE (t) == REFERENCE_TYPE |
67 | || (VOID_TYPE_P (t) && cxx_dialect >= cxx14)) | |
09b42213 | 68 | return true; |
69 | if (CLASS_TYPE_P (t)) | |
70 | { | |
71 | t = complete_type (t); | |
72 | gcc_assert (COMPLETE_TYPE_P (t) || errorcount); | |
73 | return CLASSTYPE_LITERAL_P (t); | |
74 | } | |
75 | if (TREE_CODE (t) == ARRAY_TYPE) | |
76 | return literal_type_p (strip_array_types (t)); | |
77 | return false; | |
78 | } | |
79 | ||
80 | /* If DECL is a variable declared `constexpr', require its type | |
81 | be literal. Return the DECL if OK, otherwise NULL. */ | |
82 | ||
83 | tree | |
84 | ensure_literal_type_for_constexpr_object (tree decl) | |
85 | { | |
86 | tree type = TREE_TYPE (decl); | |
87 | if (VAR_P (decl) | |
88 | && (DECL_DECLARED_CONSTEXPR_P (decl) | |
89 | || var_in_constexpr_fn (decl)) | |
90 | && !processing_template_decl) | |
91 | { | |
92 | tree stype = strip_array_types (type); | |
93 | if (CLASS_TYPE_P (stype) && !COMPLETE_TYPE_P (complete_type (stype))) | |
94 | /* Don't complain here, we'll complain about incompleteness | |
95 | when we try to initialize the variable. */; | |
96 | else if (!literal_type_p (type)) | |
97 | { | |
98 | if (DECL_DECLARED_CONSTEXPR_P (decl)) | |
e45408ff | 99 | { |
100 | error ("the type %qT of constexpr variable %qD is not literal", | |
101 | type, decl); | |
102 | explain_non_literal_class (type); | |
103 | } | |
09b42213 | 104 | else |
9c96033c | 105 | { |
e45408ff | 106 | if (!DECL_TEMPLATE_INSTANTIATION (current_function_decl)) |
107 | { | |
108 | error ("variable %qD of non-literal type %qT in %<constexpr%> " | |
109 | "function", decl, type); | |
110 | explain_non_literal_class (type); | |
111 | } | |
9c96033c | 112 | cp_function_chain->invalid_constexpr = true; |
113 | } | |
09b42213 | 114 | return NULL; |
115 | } | |
116 | } | |
117 | return decl; | |
118 | } | |
119 | ||
120 | /* Representation of entries in the constexpr function definition table. */ | |
121 | ||
122 | struct GTY((for_user)) constexpr_fundef { | |
123 | tree decl; | |
124 | tree body; | |
125 | }; | |
126 | ||
127 | struct constexpr_fundef_hasher : ggc_hasher<constexpr_fundef *> | |
128 | { | |
129 | static hashval_t hash (constexpr_fundef *); | |
130 | static bool equal (constexpr_fundef *, constexpr_fundef *); | |
131 | }; | |
132 | ||
133 | /* This table holds all constexpr function definitions seen in | |
134 | the current translation unit. */ | |
135 | ||
136 | static GTY (()) hash_table<constexpr_fundef_hasher> *constexpr_fundef_table; | |
137 | ||
138 | /* Utility function used for managing the constexpr function table. | |
139 | Return true if the entries pointed to by P and Q are for the | |
140 | same constexpr function. */ | |
141 | ||
142 | inline bool | |
143 | constexpr_fundef_hasher::equal (constexpr_fundef *lhs, constexpr_fundef *rhs) | |
144 | { | |
145 | return lhs->decl == rhs->decl; | |
146 | } | |
147 | ||
148 | /* Utility function used for managing the constexpr function table. | |
149 | Return a hash value for the entry pointed to by Q. */ | |
150 | ||
151 | inline hashval_t | |
152 | constexpr_fundef_hasher::hash (constexpr_fundef *fundef) | |
153 | { | |
154 | return DECL_UID (fundef->decl); | |
155 | } | |
156 | ||
157 | /* Return a previously saved definition of function FUN. */ | |
158 | ||
159 | static constexpr_fundef * | |
160 | retrieve_constexpr_fundef (tree fun) | |
161 | { | |
162 | constexpr_fundef fundef = { NULL, NULL }; | |
163 | if (constexpr_fundef_table == NULL) | |
164 | return NULL; | |
165 | ||
166 | fundef.decl = fun; | |
167 | return constexpr_fundef_table->find (&fundef); | |
168 | } | |
169 | ||
170 | /* Check whether the parameter and return types of FUN are valid for a | |
171 | constexpr function, and complain if COMPLAIN. */ | |
172 | ||
173 | static bool | |
174 | is_valid_constexpr_fn (tree fun, bool complain) | |
175 | { | |
176 | bool ret = true; | |
177 | ||
178 | if (DECL_INHERITED_CTOR_BASE (fun) | |
179 | && TREE_CODE (fun) == TEMPLATE_DECL) | |
180 | { | |
181 | ret = false; | |
182 | if (complain) | |
183 | error ("inherited constructor %qD is not constexpr", | |
184 | get_inherited_ctor (fun)); | |
185 | } | |
186 | else | |
187 | { | |
188 | for (tree parm = FUNCTION_FIRST_USER_PARM (fun); | |
189 | parm != NULL_TREE; parm = TREE_CHAIN (parm)) | |
190 | if (!literal_type_p (TREE_TYPE (parm))) | |
191 | { | |
192 | ret = false; | |
193 | if (complain) | |
194 | { | |
195 | error ("invalid type for parameter %d of constexpr " | |
196 | "function %q+#D", DECL_PARM_INDEX (parm), fun); | |
197 | explain_non_literal_class (TREE_TYPE (parm)); | |
198 | } | |
199 | } | |
200 | } | |
201 | ||
202 | if (!DECL_CONSTRUCTOR_P (fun)) | |
203 | { | |
204 | tree rettype = TREE_TYPE (TREE_TYPE (fun)); | |
205 | if (!literal_type_p (rettype)) | |
206 | { | |
207 | ret = false; | |
208 | if (complain) | |
209 | { | |
210 | error ("invalid return type %qT of constexpr function %q+D", | |
211 | rettype, fun); | |
212 | explain_non_literal_class (rettype); | |
213 | } | |
214 | } | |
215 | ||
216 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
217 | && !CLASSTYPE_LITERAL_P (DECL_CONTEXT (fun))) | |
218 | { | |
219 | ret = false; | |
220 | if (complain) | |
221 | { | |
222 | error ("enclosing class of constexpr non-static member " | |
223 | "function %q+#D is not a literal type", fun); | |
224 | explain_non_literal_class (DECL_CONTEXT (fun)); | |
225 | } | |
226 | } | |
227 | } | |
228 | else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun))) | |
229 | { | |
230 | ret = false; | |
231 | if (complain) | |
232 | error ("%q#T has virtual base classes", DECL_CONTEXT (fun)); | |
233 | } | |
234 | ||
235 | return ret; | |
236 | } | |
237 | ||
238 | /* Subroutine of build_data_member_initialization. MEMBER is a COMPONENT_REF | |
239 | for a member of an anonymous aggregate, INIT is the initializer for that | |
240 | member, and VEC_OUTER is the vector of constructor elements for the class | |
241 | whose constructor we are processing. Add the initializer to the vector | |
242 | and return true to indicate success. */ | |
243 | ||
244 | static bool | |
245 | build_anon_member_initialization (tree member, tree init, | |
246 | vec<constructor_elt, va_gc> **vec_outer) | |
247 | { | |
248 | /* MEMBER presents the relevant fields from the inside out, but we need | |
249 | to build up the initializer from the outside in so that we can reuse | |
250 | previously built CONSTRUCTORs if this is, say, the second field in an | |
251 | anonymous struct. So we use a vec as a stack. */ | |
252 | auto_vec<tree, 2> fields; | |
253 | do | |
254 | { | |
255 | fields.safe_push (TREE_OPERAND (member, 1)); | |
256 | member = TREE_OPERAND (member, 0); | |
257 | } | |
258 | while (ANON_AGGR_TYPE_P (TREE_TYPE (member)) | |
259 | && TREE_CODE (member) == COMPONENT_REF); | |
260 | ||
261 | /* VEC has the constructor elements vector for the context of FIELD. | |
262 | If FIELD is an anonymous aggregate, we will push inside it. */ | |
263 | vec<constructor_elt, va_gc> **vec = vec_outer; | |
264 | tree field; | |
265 | while (field = fields.pop(), | |
266 | ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
267 | { | |
268 | tree ctor; | |
269 | /* If there is already an outer constructor entry for the anonymous | |
270 | aggregate FIELD, use it; otherwise, insert one. */ | |
271 | if (vec_safe_is_empty (*vec) | |
272 | || (*vec)->last().index != field) | |
273 | { | |
274 | ctor = build_constructor (TREE_TYPE (field), NULL); | |
275 | CONSTRUCTOR_APPEND_ELT (*vec, field, ctor); | |
276 | } | |
277 | else | |
278 | ctor = (*vec)->last().value; | |
279 | vec = &CONSTRUCTOR_ELTS (ctor); | |
280 | } | |
281 | ||
282 | /* Now we're at the innermost field, the one that isn't an anonymous | |
283 | aggregate. Add its initializer to the CONSTRUCTOR and we're done. */ | |
284 | gcc_assert (fields.is_empty()); | |
285 | CONSTRUCTOR_APPEND_ELT (*vec, field, init); | |
286 | ||
287 | return true; | |
288 | } | |
289 | ||
290 | /* Subroutine of build_constexpr_constructor_member_initializers. | |
291 | The expression tree T represents a data member initialization | |
292 | in a (constexpr) constructor definition. Build a pairing of | |
293 | the data member with its initializer, and prepend that pair | |
294 | to the existing initialization pair INITS. */ | |
295 | ||
296 | static bool | |
297 | build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec) | |
298 | { | |
299 | tree member, init; | |
300 | if (TREE_CODE (t) == CLEANUP_POINT_EXPR) | |
301 | t = TREE_OPERAND (t, 0); | |
302 | if (TREE_CODE (t) == EXPR_STMT) | |
303 | t = TREE_OPERAND (t, 0); | |
304 | if (t == error_mark_node) | |
305 | return false; | |
306 | if (TREE_CODE (t) == STATEMENT_LIST) | |
307 | { | |
308 | tree_stmt_iterator i; | |
309 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
310 | { | |
311 | if (! build_data_member_initialization (tsi_stmt (i), vec)) | |
312 | return false; | |
313 | } | |
314 | return true; | |
315 | } | |
316 | if (TREE_CODE (t) == CLEANUP_STMT) | |
317 | { | |
318 | /* We can't see a CLEANUP_STMT in a constructor for a literal class, | |
319 | but we can in a constexpr constructor for a non-literal class. Just | |
320 | ignore it; either all the initialization will be constant, in which | |
321 | case the cleanup can't run, or it can't be constexpr. | |
322 | Still recurse into CLEANUP_BODY. */ | |
323 | return build_data_member_initialization (CLEANUP_BODY (t), vec); | |
324 | } | |
325 | if (TREE_CODE (t) == CONVERT_EXPR) | |
326 | t = TREE_OPERAND (t, 0); | |
327 | if (TREE_CODE (t) == INIT_EXPR | |
9c96033c | 328 | /* vptr initialization shows up as a MODIFY_EXPR. In C++14 we only |
329 | use what this function builds for cx_check_missing_mem_inits, and | |
330 | assignment in the ctor body doesn't count. */ | |
331 | || (cxx_dialect < cxx14 && TREE_CODE (t) == MODIFY_EXPR)) | |
09b42213 | 332 | { |
333 | member = TREE_OPERAND (t, 0); | |
334 | init = break_out_target_exprs (TREE_OPERAND (t, 1)); | |
335 | } | |
336 | else if (TREE_CODE (t) == CALL_EXPR) | |
337 | { | |
9c96033c | 338 | tree fn = get_callee_fndecl (t); |
339 | if (!fn || !DECL_CONSTRUCTOR_P (fn)) | |
340 | /* We're only interested in calls to subobject constructors. */ | |
341 | return true; | |
09b42213 | 342 | member = CALL_EXPR_ARG (t, 0); |
343 | /* We don't use build_cplus_new here because it complains about | |
344 | abstract bases. Leaving the call unwrapped means that it has the | |
345 | wrong type, but cxx_eval_constant_expression doesn't care. */ | |
346 | init = break_out_target_exprs (t); | |
347 | } | |
348 | else if (TREE_CODE (t) == BIND_EXPR) | |
349 | return build_data_member_initialization (BIND_EXPR_BODY (t), vec); | |
09b42213 | 350 | else |
9c96033c | 351 | /* Don't add anything else to the CONSTRUCTOR. */ |
352 | return true; | |
09b42213 | 353 | if (INDIRECT_REF_P (member)) |
354 | member = TREE_OPERAND (member, 0); | |
355 | if (TREE_CODE (member) == NOP_EXPR) | |
356 | { | |
357 | tree op = member; | |
358 | STRIP_NOPS (op); | |
359 | if (TREE_CODE (op) == ADDR_EXPR) | |
360 | { | |
361 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
362 | (TREE_TYPE (TREE_TYPE (op)), | |
363 | TREE_TYPE (TREE_TYPE (member)))); | |
364 | /* Initializing a cv-qualified member; we need to look through | |
365 | the const_cast. */ | |
366 | member = op; | |
367 | } | |
368 | else if (op == current_class_ptr | |
369 | && (same_type_ignoring_top_level_qualifiers_p | |
370 | (TREE_TYPE (TREE_TYPE (member)), | |
371 | current_class_type))) | |
372 | /* Delegating constructor. */ | |
373 | member = op; | |
374 | else | |
375 | { | |
376 | /* This is an initializer for an empty base; keep it for now so | |
377 | we can check it in cxx_eval_bare_aggregate. */ | |
378 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (member)))); | |
379 | } | |
380 | } | |
381 | if (TREE_CODE (member) == ADDR_EXPR) | |
382 | member = TREE_OPERAND (member, 0); | |
383 | if (TREE_CODE (member) == COMPONENT_REF) | |
384 | { | |
385 | tree aggr = TREE_OPERAND (member, 0); | |
386 | if (TREE_CODE (aggr) != COMPONENT_REF) | |
387 | /* Normal member initialization. */ | |
388 | member = TREE_OPERAND (member, 1); | |
389 | else if (ANON_AGGR_TYPE_P (TREE_TYPE (aggr))) | |
390 | /* Initializing a member of an anonymous union. */ | |
391 | return build_anon_member_initialization (member, init, vec); | |
392 | else | |
393 | /* We're initializing a vtable pointer in a base. Leave it as | |
394 | COMPONENT_REF so we remember the path to get to the vfield. */ | |
395 | gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node); | |
396 | } | |
397 | ||
398 | CONSTRUCTOR_APPEND_ELT (*vec, member, init); | |
399 | return true; | |
400 | } | |
401 | ||
402 | /* Subroutine of check_constexpr_ctor_body_1 and constexpr_fn_retval. | |
403 | In C++11 mode checks that the TYPE_DECLs in the BIND_EXPR_VARS of a | |
404 | BIND_EXPR conform to 7.1.5/3/4 on typedef and alias declarations. */ | |
405 | ||
406 | static bool | |
407 | check_constexpr_bind_expr_vars (tree t) | |
408 | { | |
409 | gcc_assert (TREE_CODE (t) == BIND_EXPR); | |
410 | ||
09b42213 | 411 | for (tree var = BIND_EXPR_VARS (t); var; var = DECL_CHAIN (var)) |
412 | if (TREE_CODE (var) == TYPE_DECL | |
04103c39 | 413 | && DECL_IMPLICIT_TYPEDEF_P (var) |
414 | && !LAMBDA_TYPE_P (TREE_TYPE (var))) | |
09b42213 | 415 | return false; |
416 | return true; | |
417 | } | |
418 | ||
419 | /* Subroutine of check_constexpr_ctor_body. */ | |
420 | ||
421 | static bool | |
422 | check_constexpr_ctor_body_1 (tree last, tree list) | |
423 | { | |
424 | switch (TREE_CODE (list)) | |
425 | { | |
426 | case DECL_EXPR: | |
427 | if (TREE_CODE (DECL_EXPR_DECL (list)) == USING_DECL) | |
428 | return true; | |
09b42213 | 429 | return false; |
430 | ||
431 | case CLEANUP_POINT_EXPR: | |
432 | return check_constexpr_ctor_body (last, TREE_OPERAND (list, 0), | |
433 | /*complain=*/false); | |
434 | ||
435 | case BIND_EXPR: | |
436 | if (!check_constexpr_bind_expr_vars (list) | |
437 | || !check_constexpr_ctor_body (last, BIND_EXPR_BODY (list), | |
438 | /*complain=*/false)) | |
439 | return false; | |
440 | return true; | |
441 | ||
442 | case USING_STMT: | |
443 | case STATIC_ASSERT: | |
444 | return true; | |
445 | ||
446 | default: | |
447 | return false; | |
448 | } | |
449 | } | |
450 | ||
451 | /* Make sure that there are no statements after LAST in the constructor | |
452 | body represented by LIST. */ | |
453 | ||
454 | bool | |
455 | check_constexpr_ctor_body (tree last, tree list, bool complain) | |
456 | { | |
9c96033c | 457 | /* C++14 doesn't require a constexpr ctor to have an empty body. */ |
458 | if (cxx_dialect >= cxx14) | |
459 | return true; | |
460 | ||
09b42213 | 461 | bool ok = true; |
462 | if (TREE_CODE (list) == STATEMENT_LIST) | |
463 | { | |
464 | tree_stmt_iterator i = tsi_last (list); | |
465 | for (; !tsi_end_p (i); tsi_prev (&i)) | |
466 | { | |
467 | tree t = tsi_stmt (i); | |
468 | if (t == last) | |
469 | break; | |
470 | if (!check_constexpr_ctor_body_1 (last, t)) | |
471 | { | |
472 | ok = false; | |
473 | break; | |
474 | } | |
475 | } | |
476 | } | |
477 | else if (list != last | |
478 | && !check_constexpr_ctor_body_1 (last, list)) | |
479 | ok = false; | |
480 | if (!ok) | |
481 | { | |
482 | if (complain) | |
483 | error ("constexpr constructor does not have empty body"); | |
484 | DECL_DECLARED_CONSTEXPR_P (current_function_decl) = false; | |
485 | } | |
486 | return ok; | |
487 | } | |
488 | ||
489 | /* V is a vector of constructor elements built up for the base and member | |
490 | initializers of a constructor for TYPE. They need to be in increasing | |
491 | offset order, which they might not be yet if TYPE has a primary base | |
492 | which is not first in the base-clause or a vptr and at least one base | |
493 | all of which are non-primary. */ | |
494 | ||
495 | static vec<constructor_elt, va_gc> * | |
496 | sort_constexpr_mem_initializers (tree type, vec<constructor_elt, va_gc> *v) | |
497 | { | |
498 | tree pri = CLASSTYPE_PRIMARY_BINFO (type); | |
499 | tree field_type; | |
500 | unsigned i; | |
501 | constructor_elt *ce; | |
502 | ||
503 | if (pri) | |
504 | field_type = BINFO_TYPE (pri); | |
505 | else if (TYPE_CONTAINS_VPTR_P (type)) | |
506 | field_type = vtbl_ptr_type_node; | |
507 | else | |
508 | return v; | |
509 | ||
510 | /* Find the element for the primary base or vptr and move it to the | |
511 | beginning of the vec. */ | |
512 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
513 | if (TREE_TYPE (ce->index) == field_type) | |
514 | break; | |
515 | ||
516 | if (i > 0 && i < vec_safe_length (v)) | |
517 | { | |
518 | vec<constructor_elt, va_gc> &vref = *v; | |
519 | constructor_elt elt = vref[i]; | |
520 | for (; i > 0; --i) | |
521 | vref[i] = vref[i-1]; | |
522 | vref[0] = elt; | |
523 | } | |
524 | ||
525 | return v; | |
526 | } | |
527 | ||
528 | /* Build compile-time evalable representations of member-initializer list | |
529 | for a constexpr constructor. */ | |
530 | ||
531 | static tree | |
532 | build_constexpr_constructor_member_initializers (tree type, tree body) | |
533 | { | |
534 | vec<constructor_elt, va_gc> *vec = NULL; | |
535 | bool ok = true; | |
536 | if (TREE_CODE (body) == MUST_NOT_THROW_EXPR | |
537 | || TREE_CODE (body) == EH_SPEC_BLOCK) | |
538 | body = TREE_OPERAND (body, 0); | |
539 | if (TREE_CODE (body) == STATEMENT_LIST) | |
8a36d0ec | 540 | { |
541 | tree_stmt_iterator i = tsi_start (body); | |
542 | while (true) | |
543 | { | |
544 | body = tsi_stmt (i); | |
545 | if (TREE_CODE (body) == BIND_EXPR) | |
546 | break; | |
547 | tsi_next (&i); | |
548 | } | |
549 | } | |
09b42213 | 550 | body = BIND_EXPR_BODY (body); |
551 | if (TREE_CODE (body) == CLEANUP_POINT_EXPR) | |
552 | { | |
553 | body = TREE_OPERAND (body, 0); | |
554 | if (TREE_CODE (body) == EXPR_STMT) | |
555 | body = TREE_OPERAND (body, 0); | |
556 | if (TREE_CODE (body) == INIT_EXPR | |
557 | && (same_type_ignoring_top_level_qualifiers_p | |
558 | (TREE_TYPE (TREE_OPERAND (body, 0)), | |
559 | current_class_type))) | |
560 | { | |
561 | /* Trivial copy. */ | |
562 | return TREE_OPERAND (body, 1); | |
563 | } | |
564 | ok = build_data_member_initialization (body, &vec); | |
565 | } | |
566 | else if (TREE_CODE (body) == STATEMENT_LIST) | |
567 | { | |
568 | tree_stmt_iterator i; | |
569 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
570 | { | |
571 | ok = build_data_member_initialization (tsi_stmt (i), &vec); | |
572 | if (!ok) | |
573 | break; | |
574 | } | |
575 | } | |
576 | else if (TREE_CODE (body) == TRY_BLOCK) | |
577 | { | |
578 | error ("body of %<constexpr%> constructor cannot be " | |
579 | "a function-try-block"); | |
580 | return error_mark_node; | |
581 | } | |
582 | else if (EXPR_P (body)) | |
583 | ok = build_data_member_initialization (body, &vec); | |
584 | else | |
585 | gcc_assert (errorcount > 0); | |
586 | if (ok) | |
587 | { | |
588 | if (vec_safe_length (vec) > 0) | |
589 | { | |
590 | /* In a delegating constructor, return the target. */ | |
591 | constructor_elt *ce = &(*vec)[0]; | |
592 | if (ce->index == current_class_ptr) | |
593 | { | |
594 | body = ce->value; | |
595 | vec_free (vec); | |
596 | return body; | |
597 | } | |
598 | } | |
599 | vec = sort_constexpr_mem_initializers (type, vec); | |
600 | return build_constructor (type, vec); | |
601 | } | |
602 | else | |
603 | return error_mark_node; | |
604 | } | |
605 | ||
606 | /* Subroutine of register_constexpr_fundef. BODY is the body of a function | |
607 | declared to be constexpr, or a sub-statement thereof. Returns the | |
608 | return value if suitable, error_mark_node for a statement not allowed in | |
609 | a constexpr function, or NULL_TREE if no return value was found. */ | |
610 | ||
611 | static tree | |
612 | constexpr_fn_retval (tree body) | |
613 | { | |
614 | switch (TREE_CODE (body)) | |
615 | { | |
616 | case STATEMENT_LIST: | |
617 | { | |
618 | tree_stmt_iterator i; | |
619 | tree expr = NULL_TREE; | |
620 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
621 | { | |
622 | tree s = constexpr_fn_retval (tsi_stmt (i)); | |
623 | if (s == error_mark_node) | |
624 | return error_mark_node; | |
625 | else if (s == NULL_TREE) | |
626 | /* Keep iterating. */; | |
627 | else if (expr) | |
628 | /* Multiple return statements. */ | |
629 | return error_mark_node; | |
630 | else | |
631 | expr = s; | |
632 | } | |
633 | return expr; | |
634 | } | |
635 | ||
636 | case RETURN_EXPR: | |
637 | return break_out_target_exprs (TREE_OPERAND (body, 0)); | |
638 | ||
639 | case DECL_EXPR: | |
394aed6a | 640 | { |
641 | tree decl = DECL_EXPR_DECL (body); | |
642 | if (TREE_CODE (decl) == USING_DECL | |
643 | /* Accept __func__, __FUNCTION__, and __PRETTY_FUNCTION__. */ | |
644 | || DECL_ARTIFICIAL (decl)) | |
645 | return NULL_TREE; | |
646 | return error_mark_node; | |
647 | } | |
09b42213 | 648 | |
649 | case CLEANUP_POINT_EXPR: | |
650 | return constexpr_fn_retval (TREE_OPERAND (body, 0)); | |
651 | ||
652 | case BIND_EXPR: | |
653 | if (!check_constexpr_bind_expr_vars (body)) | |
654 | return error_mark_node; | |
655 | return constexpr_fn_retval (BIND_EXPR_BODY (body)); | |
656 | ||
657 | case USING_STMT: | |
658 | return NULL_TREE; | |
659 | ||
660 | default: | |
661 | return error_mark_node; | |
662 | } | |
663 | } | |
664 | ||
665 | /* Subroutine of register_constexpr_fundef. BODY is the DECL_SAVED_TREE of | |
666 | FUN; do the necessary transformations to turn it into a single expression | |
667 | that we can store in the hash table. */ | |
668 | ||
669 | static tree | |
670 | massage_constexpr_body (tree fun, tree body) | |
671 | { | |
672 | if (DECL_CONSTRUCTOR_P (fun)) | |
673 | body = build_constexpr_constructor_member_initializers | |
674 | (DECL_CONTEXT (fun), body); | |
9c96033c | 675 | else if (cxx_dialect < cxx14) |
09b42213 | 676 | { |
677 | if (TREE_CODE (body) == EH_SPEC_BLOCK) | |
678 | body = EH_SPEC_STMTS (body); | |
679 | if (TREE_CODE (body) == MUST_NOT_THROW_EXPR) | |
680 | body = TREE_OPERAND (body, 0); | |
681 | body = constexpr_fn_retval (body); | |
682 | } | |
683 | return body; | |
684 | } | |
685 | ||
686 | /* FUN is a constexpr constructor with massaged body BODY. Return true | |
687 | if some bases/fields are uninitialized, and complain if COMPLAIN. */ | |
688 | ||
689 | static bool | |
690 | cx_check_missing_mem_inits (tree fun, tree body, bool complain) | |
691 | { | |
692 | bool bad; | |
693 | tree field; | |
694 | unsigned i, nelts; | |
695 | tree ctype; | |
696 | ||
697 | if (TREE_CODE (body) != CONSTRUCTOR) | |
698 | return false; | |
699 | ||
700 | nelts = CONSTRUCTOR_NELTS (body); | |
701 | ctype = DECL_CONTEXT (fun); | |
702 | field = TYPE_FIELDS (ctype); | |
703 | ||
704 | if (TREE_CODE (ctype) == UNION_TYPE) | |
705 | { | |
706 | if (nelts == 0 && next_initializable_field (field)) | |
707 | { | |
708 | if (complain) | |
709 | error ("%<constexpr%> constructor for union %qT must " | |
710 | "initialize exactly one non-static data member", ctype); | |
711 | return true; | |
712 | } | |
713 | return false; | |
714 | } | |
715 | ||
716 | bad = false; | |
717 | for (i = 0; i <= nelts; ++i) | |
718 | { | |
719 | tree index; | |
720 | if (i == nelts) | |
721 | index = NULL_TREE; | |
722 | else | |
723 | { | |
724 | index = CONSTRUCTOR_ELT (body, i)->index; | |
725 | /* Skip base and vtable inits. */ | |
726 | if (TREE_CODE (index) != FIELD_DECL | |
727 | || DECL_ARTIFICIAL (index)) | |
728 | continue; | |
729 | } | |
730 | for (; field != index; field = DECL_CHAIN (field)) | |
731 | { | |
732 | tree ftype; | |
733 | if (TREE_CODE (field) != FIELD_DECL | |
734 | || (DECL_C_BIT_FIELD (field) && !DECL_NAME (field)) | |
735 | || DECL_ARTIFICIAL (field)) | |
736 | continue; | |
737 | ftype = strip_array_types (TREE_TYPE (field)); | |
738 | if (type_has_constexpr_default_constructor (ftype)) | |
739 | { | |
740 | /* It's OK to skip a member with a trivial constexpr ctor. | |
741 | A constexpr ctor that isn't trivial should have been | |
742 | added in by now. */ | |
743 | gcc_checking_assert (!TYPE_HAS_COMPLEX_DFLT (ftype) | |
744 | || errorcount != 0); | |
745 | continue; | |
746 | } | |
747 | if (!complain) | |
748 | return true; | |
859e2c29 | 749 | error ("member %qD must be initialized by mem-initializer " |
750 | "in %<constexpr%> constructor", field); | |
751 | inform (DECL_SOURCE_LOCATION (field), "declared here"); | |
09b42213 | 752 | bad = true; |
753 | } | |
754 | if (field == NULL_TREE) | |
755 | break; | |
756 | field = DECL_CHAIN (field); | |
757 | } | |
758 | ||
759 | return bad; | |
760 | } | |
761 | ||
762 | /* We are processing the definition of the constexpr function FUN. | |
763 | Check that its BODY fulfills the propriate requirements and | |
764 | enter it in the constexpr function definition table. | |
765 | For constructor BODY is actually the TREE_LIST of the | |
766 | member-initializer list. */ | |
767 | ||
768 | tree | |
769 | register_constexpr_fundef (tree fun, tree body) | |
770 | { | |
771 | constexpr_fundef entry; | |
772 | constexpr_fundef **slot; | |
773 | ||
774 | if (!is_valid_constexpr_fn (fun, !DECL_GENERATED_P (fun))) | |
775 | return NULL; | |
776 | ||
777 | body = massage_constexpr_body (fun, body); | |
778 | if (body == NULL_TREE || body == error_mark_node) | |
779 | { | |
780 | if (!DECL_CONSTRUCTOR_P (fun)) | |
781 | error ("body of constexpr function %qD not a return-statement", fun); | |
782 | return NULL; | |
783 | } | |
784 | ||
785 | if (!potential_rvalue_constant_expression (body)) | |
786 | { | |
787 | if (!DECL_GENERATED_P (fun)) | |
788 | require_potential_rvalue_constant_expression (body); | |
789 | return NULL; | |
790 | } | |
791 | ||
792 | if (DECL_CONSTRUCTOR_P (fun) | |
793 | && cx_check_missing_mem_inits (fun, body, !DECL_GENERATED_P (fun))) | |
794 | return NULL; | |
795 | ||
796 | /* Create the constexpr function table if necessary. */ | |
797 | if (constexpr_fundef_table == NULL) | |
798 | constexpr_fundef_table | |
799 | = hash_table<constexpr_fundef_hasher>::create_ggc (101); | |
800 | ||
801 | entry.decl = fun; | |
802 | entry.body = body; | |
803 | slot = constexpr_fundef_table->find_slot (&entry, INSERT); | |
804 | ||
805 | gcc_assert (*slot == NULL); | |
806 | *slot = ggc_alloc<constexpr_fundef> (); | |
807 | **slot = entry; | |
808 | ||
809 | return fun; | |
810 | } | |
811 | ||
812 | /* FUN is a non-constexpr function called in a context that requires a | |
813 | constant expression. If it comes from a constexpr template, explain why | |
814 | the instantiation isn't constexpr. */ | |
815 | ||
816 | void | |
817 | explain_invalid_constexpr_fn (tree fun) | |
818 | { | |
819 | static hash_set<tree> *diagnosed; | |
820 | tree body; | |
821 | location_t save_loc; | |
822 | /* Only diagnose defaulted functions or instantiations. */ | |
823 | if (!DECL_DEFAULTED_FN (fun) | |
824 | && !is_instantiation_of_constexpr (fun)) | |
825 | return; | |
826 | if (diagnosed == NULL) | |
827 | diagnosed = new hash_set<tree>; | |
828 | if (diagnosed->add (fun)) | |
829 | /* Already explained. */ | |
830 | return; | |
831 | ||
832 | save_loc = input_location; | |
833 | input_location = DECL_SOURCE_LOCATION (fun); | |
834 | inform (0, "%q+D is not usable as a constexpr function because:", fun); | |
835 | /* First check the declaration. */ | |
836 | if (is_valid_constexpr_fn (fun, true)) | |
837 | { | |
838 | /* Then if it's OK, the body. */ | |
839 | if (!DECL_DECLARED_CONSTEXPR_P (fun)) | |
840 | explain_implicit_non_constexpr (fun); | |
841 | else | |
842 | { | |
843 | body = massage_constexpr_body (fun, DECL_SAVED_TREE (fun)); | |
844 | require_potential_rvalue_constant_expression (body); | |
845 | if (DECL_CONSTRUCTOR_P (fun)) | |
846 | cx_check_missing_mem_inits (fun, body, true); | |
847 | } | |
848 | } | |
849 | input_location = save_loc; | |
850 | } | |
851 | ||
852 | /* Objects of this type represent calls to constexpr functions | |
853 | along with the bindings of parameters to their arguments, for | |
854 | the purpose of compile time evaluation. */ | |
855 | ||
856 | struct GTY((for_user)) constexpr_call { | |
857 | /* Description of the constexpr function definition. */ | |
858 | constexpr_fundef *fundef; | |
859 | /* Parameter bindings environment. A TREE_LIST where each TREE_PURPOSE | |
860 | is a parameter _DECL and the TREE_VALUE is the value of the parameter. | |
861 | Note: This arrangement is made to accommodate the use of | |
862 | iterative_hash_template_arg (see pt.c). If you change this | |
863 | representation, also change the hash calculation in | |
864 | cxx_eval_call_expression. */ | |
865 | tree bindings; | |
866 | /* Result of the call. | |
867 | NULL means the call is being evaluated. | |
868 | error_mark_node means that the evaluation was erroneous; | |
869 | otherwise, the actuall value of the call. */ | |
870 | tree result; | |
871 | /* The hash of this call; we remember it here to avoid having to | |
872 | recalculate it when expanding the hash table. */ | |
873 | hashval_t hash; | |
874 | }; | |
875 | ||
876 | struct constexpr_call_hasher : ggc_hasher<constexpr_call *> | |
877 | { | |
878 | static hashval_t hash (constexpr_call *); | |
879 | static bool equal (constexpr_call *, constexpr_call *); | |
cf72f34d | 880 | }; |
881 | ||
882 | /* The constexpr expansion context. CALL is the current function | |
883 | expansion, CTOR is the current aggregate initializer, OBJECT is the | |
884 | object being initialized by CTOR, either a VAR_DECL or a _REF. VALUES | |
885 | is a map of values of variables initialized within the expression. */ | |
886 | ||
887 | struct constexpr_ctx { | |
f9885b8a | 888 | /* The innermost call we're evaluating. */ |
cf72f34d | 889 | constexpr_call *call; |
f9885b8a | 890 | /* Values for any temporaries or local variables within the |
891 | constant-expression. */ | |
cf72f34d | 892 | hash_map<tree,tree> *values; |
f9885b8a | 893 | /* The CONSTRUCTOR we're currently building up for an aggregate |
894 | initializer. */ | |
cf72f34d | 895 | tree ctor; |
f9885b8a | 896 | /* The object we're building the CONSTRUCTOR for. */ |
cf72f34d | 897 | tree object; |
f9885b8a | 898 | /* Whether we should error on a non-constant expression or fail quietly. */ |
f83e6885 | 899 | bool quiet; |
f9885b8a | 900 | /* Whether we are strictly conforming to constant expression rules or |
901 | trying harder to get a constant value. */ | |
2055d27a | 902 | bool strict; |
cf72f34d | 903 | }; |
09b42213 | 904 | |
905 | /* A table of all constexpr calls that have been evaluated by the | |
906 | compiler in this translation unit. */ | |
907 | ||
908 | static GTY (()) hash_table<constexpr_call_hasher> *constexpr_call_table; | |
909 | ||
cf72f34d | 910 | static tree cxx_eval_constant_expression (const constexpr_ctx *, tree, |
b2a43197 | 911 | bool, bool *, bool *, tree * = NULL); |
09b42213 | 912 | |
913 | /* Compute a hash value for a constexpr call representation. */ | |
914 | ||
915 | inline hashval_t | |
916 | constexpr_call_hasher::hash (constexpr_call *info) | |
917 | { | |
918 | return info->hash; | |
919 | } | |
920 | ||
921 | /* Return true if the objects pointed to by P and Q represent calls | |
922 | to the same constexpr function with the same arguments. | |
923 | Otherwise, return false. */ | |
924 | ||
925 | bool | |
926 | constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs) | |
927 | { | |
928 | tree lhs_bindings; | |
929 | tree rhs_bindings; | |
930 | if (lhs == rhs) | |
931 | return 1; | |
932 | if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef)) | |
933 | return 0; | |
934 | lhs_bindings = lhs->bindings; | |
935 | rhs_bindings = rhs->bindings; | |
936 | while (lhs_bindings != NULL && rhs_bindings != NULL) | |
937 | { | |
938 | tree lhs_arg = TREE_VALUE (lhs_bindings); | |
939 | tree rhs_arg = TREE_VALUE (rhs_bindings); | |
940 | gcc_assert (TREE_TYPE (lhs_arg) == TREE_TYPE (rhs_arg)); | |
941 | if (!cp_tree_equal (lhs_arg, rhs_arg)) | |
942 | return 0; | |
943 | lhs_bindings = TREE_CHAIN (lhs_bindings); | |
944 | rhs_bindings = TREE_CHAIN (rhs_bindings); | |
945 | } | |
946 | return lhs_bindings == rhs_bindings; | |
947 | } | |
948 | ||
949 | /* Initialize the constexpr call table, if needed. */ | |
950 | ||
951 | static void | |
952 | maybe_initialize_constexpr_call_table (void) | |
953 | { | |
954 | if (constexpr_call_table == NULL) | |
955 | constexpr_call_table = hash_table<constexpr_call_hasher>::create_ggc (101); | |
956 | } | |
957 | ||
958 | /* We have an expression tree T that represents a call, either CALL_EXPR | |
959 | or AGGR_INIT_EXPR. If the call is lexically to a named function, | |
960 | retrun the _DECL for that function. */ | |
961 | ||
962 | static tree | |
963 | get_function_named_in_call (tree t) | |
964 | { | |
965 | tree fun = NULL; | |
966 | switch (TREE_CODE (t)) | |
967 | { | |
968 | case CALL_EXPR: | |
969 | fun = CALL_EXPR_FN (t); | |
970 | break; | |
971 | ||
972 | case AGGR_INIT_EXPR: | |
973 | fun = AGGR_INIT_EXPR_FN (t); | |
974 | break; | |
975 | ||
976 | default: | |
977 | gcc_unreachable(); | |
978 | break; | |
979 | } | |
9c96033c | 980 | if (fun && TREE_CODE (fun) == ADDR_EXPR |
09b42213 | 981 | && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL) |
982 | fun = TREE_OPERAND (fun, 0); | |
983 | return fun; | |
984 | } | |
985 | ||
986 | /* We have an expression tree T that represents a call, either CALL_EXPR | |
987 | or AGGR_INIT_EXPR. Return the Nth argument. */ | |
988 | ||
989 | static inline tree | |
990 | get_nth_callarg (tree t, int n) | |
991 | { | |
992 | switch (TREE_CODE (t)) | |
993 | { | |
994 | case CALL_EXPR: | |
995 | return CALL_EXPR_ARG (t, n); | |
996 | ||
997 | case AGGR_INIT_EXPR: | |
998 | return AGGR_INIT_EXPR_ARG (t, n); | |
999 | ||
1000 | default: | |
1001 | gcc_unreachable (); | |
1002 | return NULL; | |
1003 | } | |
1004 | } | |
1005 | ||
09b42213 | 1006 | /* Attempt to evaluate T which represents a call to a builtin function. |
1007 | We assume here that all builtin functions evaluate to scalar types | |
1008 | represented by _CST nodes. */ | |
1009 | ||
1010 | static tree | |
f1c6af10 | 1011 | cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, |
1227ba74 | 1012 | bool lval, |
09b42213 | 1013 | bool *non_constant_p, bool *overflow_p) |
1014 | { | |
1015 | const int nargs = call_expr_nargs (t); | |
1016 | tree *args = (tree *) alloca (nargs * sizeof (tree)); | |
1017 | tree new_call; | |
1018 | int i; | |
f1c6af10 | 1019 | |
1020 | /* Don't fold __builtin_constant_p within a constexpr function. */ | |
1021 | if (DECL_FUNCTION_CODE (fun) == BUILT_IN_CONSTANT_P | |
1022 | && current_function_decl | |
1023 | && DECL_DECLARED_CONSTEXPR_P (current_function_decl)) | |
09b42213 | 1024 | { |
f1c6af10 | 1025 | *non_constant_p = true; |
1026 | return t; | |
09b42213 | 1027 | } |
f1c6af10 | 1028 | |
1029 | /* Be permissive for arguments to built-ins; __builtin_constant_p should | |
1030 | return constant false for a non-constant argument. */ | |
1031 | constexpr_ctx new_ctx = *ctx; | |
1032 | new_ctx.quiet = true; | |
1033 | bool dummy1 = false, dummy2 = false; | |
1034 | for (i = 0; i < nargs; ++i) | |
1035 | args[i] = cxx_eval_constant_expression (&new_ctx, CALL_EXPR_ARG (t, i), | |
1036 | lval, &dummy1, &dummy2); | |
1037 | ||
1038 | bool save_ffbcp = force_folding_builtin_constant_p; | |
1039 | force_folding_builtin_constant_p = true; | |
9d884767 | 1040 | new_call = fold_build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t), |
1041 | CALL_EXPR_FN (t), nargs, args); | |
f1c6af10 | 1042 | force_folding_builtin_constant_p = save_ffbcp; |
09b42213 | 1043 | VERIFY_CONSTANT (new_call); |
1044 | return new_call; | |
1045 | } | |
1046 | ||
1047 | /* TEMP is the constant value of a temporary object of type TYPE. Adjust | |
1048 | the type of the value to match. */ | |
1049 | ||
1050 | static tree | |
1051 | adjust_temp_type (tree type, tree temp) | |
1052 | { | |
1053 | if (TREE_TYPE (temp) == type) | |
1054 | return temp; | |
1055 | /* Avoid wrapping an aggregate value in a NOP_EXPR. */ | |
1056 | if (TREE_CODE (temp) == CONSTRUCTOR) | |
1057 | return build_constructor (type, CONSTRUCTOR_ELTS (temp)); | |
1058 | gcc_assert (scalarish_type_p (type)); | |
1059 | return cp_fold_convert (type, temp); | |
1060 | } | |
1061 | ||
1062 | /* Subroutine of cxx_eval_call_expression. | |
1063 | We are processing a call expression (either CALL_EXPR or | |
cf72f34d | 1064 | AGGR_INIT_EXPR) in the context of CTX. Evaluate |
09b42213 | 1065 | all arguments and bind their values to correspondings |
1066 | parameters, making up the NEW_CALL context. */ | |
1067 | ||
1068 | static void | |
cf72f34d | 1069 | cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, |
09b42213 | 1070 | constexpr_call *new_call, |
c8f6aeb1 | 1071 | bool *non_constant_p, bool *overflow_p, |
1072 | bool *non_constant_args) | |
09b42213 | 1073 | { |
1074 | const int nargs = call_expr_nargs (t); | |
1075 | tree fun = new_call->fundef->decl; | |
1076 | tree parms = DECL_ARGUMENTS (fun); | |
1077 | int i; | |
9c96033c | 1078 | tree *p = &new_call->bindings; |
09b42213 | 1079 | for (i = 0; i < nargs; ++i) |
1080 | { | |
1081 | tree x, arg; | |
1082 | tree type = parms ? TREE_TYPE (parms) : void_type_node; | |
09b42213 | 1083 | x = get_nth_callarg (t, i); |
cf72f34d | 1084 | /* For member function, the first argument is a pointer to the implied |
1085 | object. For a constructor, it might still be a dummy object, in | |
9c96033c | 1086 | which case we get the real argument from ctx. */ |
cf72f34d | 1087 | if (i == 0 && DECL_CONSTRUCTOR_P (fun) |
1088 | && is_dummy_object (x)) | |
1089 | { | |
1090 | x = ctx->object; | |
cf72f34d | 1091 | x = cp_build_addr_expr (x, tf_warning_or_error); |
1092 | } | |
1227ba74 | 1093 | bool lval = false; |
1227ba74 | 1094 | arg = cxx_eval_constant_expression (ctx, x, lval, |
b2a43197 | 1095 | non_constant_p, overflow_p); |
09b42213 | 1096 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 1097 | if (*non_constant_p && ctx->quiet) |
09b42213 | 1098 | return; |
1099 | /* Just discard ellipsis args after checking their constantitude. */ | |
1100 | if (!parms) | |
1101 | continue; | |
1102 | if (*non_constant_p) | |
1103 | /* Don't try to adjust the type of non-constant args. */ | |
1104 | goto next; | |
1105 | ||
1106 | /* Make sure the binding has the same type as the parm. */ | |
1107 | if (TREE_CODE (type) != REFERENCE_TYPE) | |
1108 | arg = adjust_temp_type (type, arg); | |
c8f6aeb1 | 1109 | if (!TREE_CONSTANT (arg)) |
1110 | *non_constant_args = true; | |
9c96033c | 1111 | *p = build_tree_list (parms, arg); |
1112 | p = &TREE_CHAIN (*p); | |
09b42213 | 1113 | next: |
1114 | parms = TREE_CHAIN (parms); | |
1115 | } | |
1116 | } | |
1117 | ||
1118 | /* Variables and functions to manage constexpr call expansion context. | |
1119 | These do not need to be marked for PCH or GC. */ | |
1120 | ||
1121 | /* FIXME remember and print actual constant arguments. */ | |
1122 | static vec<tree> call_stack = vNULL; | |
1123 | static int call_stack_tick; | |
1124 | static int last_cx_error_tick; | |
1125 | ||
1126 | static bool | |
1127 | push_cx_call_context (tree call) | |
1128 | { | |
1129 | ++call_stack_tick; | |
1130 | if (!EXPR_HAS_LOCATION (call)) | |
1131 | SET_EXPR_LOCATION (call, input_location); | |
1132 | call_stack.safe_push (call); | |
1133 | if (call_stack.length () > (unsigned) max_constexpr_depth) | |
1134 | return false; | |
1135 | return true; | |
1136 | } | |
1137 | ||
1138 | static void | |
1139 | pop_cx_call_context (void) | |
1140 | { | |
1141 | ++call_stack_tick; | |
1142 | call_stack.pop (); | |
1143 | } | |
1144 | ||
1145 | vec<tree> | |
1146 | cx_error_context (void) | |
1147 | { | |
1148 | vec<tree> r = vNULL; | |
1149 | if (call_stack_tick != last_cx_error_tick | |
1150 | && !call_stack.is_empty ()) | |
1151 | r = call_stack; | |
1152 | last_cx_error_tick = call_stack_tick; | |
1153 | return r; | |
1154 | } | |
1155 | ||
1156 | /* Subroutine of cxx_eval_constant_expression. | |
1157 | Evaluate the call expression tree T in the context of OLD_CALL expression | |
1158 | evaluation. */ | |
1159 | ||
1160 | static tree | |
cf72f34d | 1161 | cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1162 | bool lval, |
09b42213 | 1163 | bool *non_constant_p, bool *overflow_p) |
1164 | { | |
1165 | location_t loc = EXPR_LOC_OR_LOC (t, input_location); | |
1166 | tree fun = get_function_named_in_call (t); | |
09b42213 | 1167 | constexpr_call new_call = { NULL, NULL, NULL, 0 }; |
09b42213 | 1168 | bool depth_ok; |
1169 | ||
6b71bdb4 | 1170 | if (fun == NULL_TREE) |
1171 | switch (CALL_EXPR_IFN (t)) | |
1172 | { | |
1173 | case IFN_UBSAN_NULL: | |
1174 | case IFN_UBSAN_BOUNDS: | |
32cf7025 | 1175 | case IFN_UBSAN_VPTR: |
6b71bdb4 | 1176 | return void_node; |
1177 | default: | |
1178 | if (!ctx->quiet) | |
1179 | error_at (loc, "call to internal function"); | |
1180 | *non_constant_p = true; | |
1181 | return t; | |
1182 | } | |
1183 | ||
09b42213 | 1184 | if (TREE_CODE (fun) != FUNCTION_DECL) |
1185 | { | |
1186 | /* Might be a constexpr function pointer. */ | |
f83e6885 | 1187 | fun = cxx_eval_constant_expression (ctx, fun, |
1227ba74 | 1188 | /*lval*/false, non_constant_p, |
b2a43197 | 1189 | overflow_p); |
09b42213 | 1190 | STRIP_NOPS (fun); |
1191 | if (TREE_CODE (fun) == ADDR_EXPR) | |
1192 | fun = TREE_OPERAND (fun, 0); | |
1193 | } | |
1194 | if (TREE_CODE (fun) != FUNCTION_DECL) | |
1195 | { | |
f83e6885 | 1196 | if (!ctx->quiet && !*non_constant_p) |
09b42213 | 1197 | error_at (loc, "expression %qE does not designate a constexpr " |
1198 | "function", fun); | |
1199 | *non_constant_p = true; | |
1200 | return t; | |
1201 | } | |
1202 | if (DECL_CLONED_FUNCTION_P (fun)) | |
1203 | fun = DECL_CLONED_FUNCTION (fun); | |
6b71bdb4 | 1204 | |
1205 | if (is_ubsan_builtin_p (fun)) | |
1206 | return void_node; | |
1207 | ||
09b42213 | 1208 | if (is_builtin_fn (fun)) |
f1c6af10 | 1209 | return cxx_eval_builtin_function_call (ctx, t, fun, |
1227ba74 | 1210 | lval, non_constant_p, overflow_p); |
09b42213 | 1211 | if (!DECL_DECLARED_CONSTEXPR_P (fun)) |
1212 | { | |
f83e6885 | 1213 | if (!ctx->quiet) |
09b42213 | 1214 | { |
1215 | error_at (loc, "call to non-constexpr function %qD", fun); | |
1216 | explain_invalid_constexpr_fn (fun); | |
1217 | } | |
1218 | *non_constant_p = true; | |
1219 | return t; | |
1220 | } | |
1221 | ||
1222 | /* Shortcut trivial constructor/op=. */ | |
1223 | if (trivial_fn_p (fun)) | |
1224 | { | |
1225 | if (call_expr_nargs (t) == 2) | |
1226 | { | |
1227 | tree arg = convert_from_reference (get_nth_callarg (t, 1)); | |
f83e6885 | 1228 | return cxx_eval_constant_expression (ctx, arg, |
1227ba74 | 1229 | lval, non_constant_p, |
b2a43197 | 1230 | overflow_p); |
09b42213 | 1231 | } |
1232 | else if (TREE_CODE (t) == AGGR_INIT_EXPR | |
1233 | && AGGR_INIT_ZERO_FIRST (t)) | |
1234 | return build_zero_init (DECL_CONTEXT (fun), NULL_TREE, false); | |
1235 | } | |
1236 | ||
8afcf831 | 1237 | /* We can't defer instantiating the function any longer. */ |
1238 | if (!DECL_INITIAL (fun) | |
1239 | && DECL_TEMPLOID_INSTANTIATION (fun)) | |
1240 | { | |
1241 | ++function_depth; | |
1242 | instantiate_decl (fun, /*defer_ok*/false, /*expl_inst*/false); | |
1243 | --function_depth; | |
1244 | } | |
1245 | ||
09b42213 | 1246 | /* If in direct recursive call, optimize definition search. */ |
cf72f34d | 1247 | if (ctx && ctx->call && ctx->call->fundef->decl == fun) |
1248 | new_call.fundef = ctx->call->fundef; | |
09b42213 | 1249 | else |
1250 | { | |
1251 | new_call.fundef = retrieve_constexpr_fundef (fun); | |
1252 | if (new_call.fundef == NULL || new_call.fundef->body == NULL) | |
1253 | { | |
f83e6885 | 1254 | if (!ctx->quiet) |
09b42213 | 1255 | { |
1256 | if (DECL_INITIAL (fun)) | |
1257 | { | |
1258 | /* The definition of fun was somehow unsuitable. */ | |
1259 | error_at (loc, "%qD called in a constant expression", fun); | |
1260 | explain_invalid_constexpr_fn (fun); | |
1261 | } | |
1262 | else | |
1263 | error_at (loc, "%qD used before its definition", fun); | |
1264 | } | |
1265 | *non_constant_p = true; | |
1266 | return t; | |
1267 | } | |
1268 | } | |
9c96033c | 1269 | |
1270 | constexpr_ctx new_ctx = *ctx; | |
1271 | if (DECL_CONSTRUCTOR_P (fun) && !ctx->object | |
1272 | && TREE_CODE (t) == AGGR_INIT_EXPR) | |
1273 | { | |
1274 | /* We want to have an initialization target for an AGGR_INIT_EXPR. | |
1275 | If we don't already have one in CTX, use the AGGR_INIT_EXPR_SLOT. */ | |
1276 | new_ctx.object = AGGR_INIT_EXPR_SLOT (t); | |
1277 | tree ctor = new_ctx.ctor = build_constructor (DECL_CONTEXT (fun), NULL); | |
1278 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor) = true; | |
1279 | ctx->values->put (new_ctx.object, ctor); | |
1280 | ctx = &new_ctx; | |
1281 | } | |
1282 | ||
c8f6aeb1 | 1283 | bool non_constant_args = false; |
cf72f34d | 1284 | cxx_bind_parameters_in_call (ctx, t, &new_call, |
c8f6aeb1 | 1285 | non_constant_p, overflow_p, &non_constant_args); |
09b42213 | 1286 | if (*non_constant_p) |
1287 | return t; | |
1288 | ||
1289 | depth_ok = push_cx_call_context (t); | |
1290 | ||
c8f6aeb1 | 1291 | tree result = NULL_TREE; |
09b42213 | 1292 | |
c8f6aeb1 | 1293 | constexpr_call *entry = NULL; |
1294 | if (!non_constant_args) | |
09b42213 | 1295 | { |
c8f6aeb1 | 1296 | new_call.hash = iterative_hash_template_arg |
1297 | (new_call.bindings, constexpr_fundef_hasher::hash (new_call.fundef)); | |
1298 | ||
1299 | /* If we have seen this call before, we are done. */ | |
1300 | maybe_initialize_constexpr_call_table (); | |
1301 | constexpr_call **slot | |
1302 | = constexpr_call_table->find_slot (&new_call, INSERT); | |
1303 | entry = *slot; | |
1304 | if (entry == NULL) | |
1305 | { | |
1306 | /* We need to keep a pointer to the entry, not just the slot, as the | |
1307 | slot can move in the call to cxx_eval_builtin_function_call. */ | |
1308 | *slot = entry = ggc_alloc<constexpr_call> (); | |
1309 | *entry = new_call; | |
1310 | } | |
1311 | /* Calls which are in progress have their result set to NULL | |
1312 | so that we can detect circular dependencies. */ | |
1313 | else if (entry->result == NULL) | |
1314 | { | |
1315 | if (!ctx->quiet) | |
1316 | error ("call has circular dependency"); | |
1317 | *non_constant_p = true; | |
1318 | entry->result = result = error_mark_node; | |
1319 | } | |
1320 | else | |
1321 | result = entry->result; | |
09b42213 | 1322 | } |
1323 | ||
1324 | if (!depth_ok) | |
1325 | { | |
f83e6885 | 1326 | if (!ctx->quiet) |
09b42213 | 1327 | error ("constexpr evaluation depth exceeds maximum of %d (use " |
1328 | "-fconstexpr-depth= to increase the maximum)", | |
1329 | max_constexpr_depth); | |
1330 | *non_constant_p = true; | |
c8f6aeb1 | 1331 | result = error_mark_node; |
09b42213 | 1332 | } |
1333 | else | |
1334 | { | |
09b42213 | 1335 | if (!result || result == error_mark_node) |
cf72f34d | 1336 | { |
88a59139 | 1337 | if (DECL_SAVED_TREE (fun) == NULL_TREE |
1338 | && (DECL_CONSTRUCTOR_P (fun) || DECL_DESTRUCTOR_P (fun))) | |
1339 | /* The maybe-in-charge 'tor had its DECL_SAVED_TREE | |
1340 | cleared, try a clone. */ | |
1341 | for (fun = DECL_CHAIN (fun); | |
1342 | fun && DECL_CLONED_FUNCTION_P (fun); | |
1343 | fun = DECL_CHAIN (fun)) | |
1344 | if (DECL_SAVED_TREE (fun)) | |
1345 | break; | |
1346 | gcc_assert (DECL_SAVED_TREE (fun)); | |
1347 | tree parms, res; | |
1348 | ||
1349 | /* Unshare the whole function body. */ | |
1350 | tree body = copy_fn (fun, parms, res); | |
1351 | ||
1352 | /* Associate the bindings with the remapped parms. */ | |
1353 | tree bound = new_call.bindings; | |
1354 | tree remapped = parms; | |
1355 | while (bound) | |
9c96033c | 1356 | { |
88a59139 | 1357 | tree oparm = TREE_PURPOSE (bound); |
1358 | tree arg = TREE_VALUE (bound); | |
1359 | gcc_assert (DECL_NAME (remapped) == DECL_NAME (oparm)); | |
1360 | ctx->values->put (remapped, arg); | |
1361 | bound = TREE_CHAIN (bound); | |
1362 | remapped = DECL_CHAIN (remapped); | |
9c96033c | 1363 | } |
88a59139 | 1364 | /* Add the RESULT_DECL to the values map, too. */ |
1365 | tree slot = NULL_TREE; | |
1366 | if (DECL_BY_REFERENCE (res)) | |
9c96033c | 1367 | { |
88a59139 | 1368 | slot = AGGR_INIT_EXPR_SLOT (t); |
1369 | tree addr = build_address (slot); | |
1370 | addr = build_nop (TREE_TYPE (res), addr); | |
1371 | ctx->values->put (res, addr); | |
1372 | ctx->values->put (slot, NULL_TREE); | |
1373 | } | |
1374 | else | |
1375 | ctx->values->put (res, NULL_TREE); | |
9c96033c | 1376 | |
88a59139 | 1377 | tree jump_target = NULL_TREE; |
1378 | cxx_eval_constant_expression (ctx, body, | |
1379 | lval, non_constant_p, overflow_p, | |
1380 | &jump_target); | |
9c96033c | 1381 | |
88a59139 | 1382 | if (DECL_CONSTRUCTOR_P (fun)) |
1383 | /* This can be null for a subobject constructor call, in | |
1384 | which case what we care about is the initialization | |
1385 | side-effects rather than the value. We could get at the | |
1386 | value by evaluating *this, but we don't bother; there's | |
1387 | no need to put such a call in the hash table. */ | |
1388 | result = lval ? ctx->object : ctx->ctor; | |
1389 | else if (VOID_TYPE_P (TREE_TYPE (res))) | |
1390 | result = void_node; | |
1391 | else | |
1392 | { | |
1393 | result = *ctx->values->get (slot ? slot : res); | |
1394 | if (result == NULL_TREE && !*non_constant_p) | |
9c96033c | 1395 | { |
88a59139 | 1396 | if (!ctx->quiet) |
1397 | error ("constexpr call flows off the end " | |
1398 | "of the function"); | |
1399 | *non_constant_p = true; | |
9c96033c | 1400 | } |
9c96033c | 1401 | } |
88a59139 | 1402 | |
1403 | /* Remove the parms/result from the values map. Is it worth | |
1404 | bothering to do this when the map itself is only live for | |
1405 | one constexpr evaluation? If so, maybe also clear out | |
1406 | other vars from call, maybe in BIND_EXPR handling? */ | |
1407 | ctx->values->remove (res); | |
1408 | if (slot) | |
1409 | ctx->values->remove (slot); | |
1410 | for (tree parm = parms; parm; parm = TREE_CHAIN (parm)) | |
1411 | ctx->values->remove (parm); | |
cf72f34d | 1412 | } |
9c96033c | 1413 | |
09b42213 | 1414 | if (result == error_mark_node) |
1415 | *non_constant_p = true; | |
1416 | if (*non_constant_p) | |
c8f6aeb1 | 1417 | result = error_mark_node; |
88a59139 | 1418 | else if (!result) |
9c96033c | 1419 | result = void_node; |
c8f6aeb1 | 1420 | if (entry) |
1421 | entry->result = result; | |
09b42213 | 1422 | } |
1423 | ||
1424 | pop_cx_call_context (); | |
1425 | return unshare_expr (result); | |
1426 | } | |
1427 | ||
1428 | /* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */ | |
1429 | ||
1430 | bool | |
1431 | reduced_constant_expression_p (tree t) | |
1432 | { | |
1433 | switch (TREE_CODE (t)) | |
1434 | { | |
1435 | case PTRMEM_CST: | |
1436 | /* Even if we can't lower this yet, it's constant. */ | |
1437 | return true; | |
1438 | ||
1439 | case CONSTRUCTOR: | |
1440 | /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */ | |
1441 | tree elt; unsigned HOST_WIDE_INT idx; | |
1442 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), idx, elt) | |
1443 | if (!reduced_constant_expression_p (elt)) | |
1444 | return false; | |
1445 | return true; | |
1446 | ||
1447 | default: | |
1448 | /* FIXME are we calling this too much? */ | |
1449 | return initializer_constant_valid_p (t, TREE_TYPE (t)) != NULL_TREE; | |
1450 | } | |
1451 | } | |
1452 | ||
1453 | /* Some expressions may have constant operands but are not constant | |
1454 | themselves, such as 1/0. Call this function (or rather, the macro | |
1455 | following it) to check for that condition. | |
1456 | ||
1457 | We only call this in places that require an arithmetic constant, not in | |
1458 | places where we might have a non-constant expression that can be a | |
1459 | component of a constant expression, such as the address of a constexpr | |
1460 | variable that might be dereferenced later. */ | |
1461 | ||
1462 | static bool | |
1463 | verify_constant (tree t, bool allow_non_constant, bool *non_constant_p, | |
1464 | bool *overflow_p) | |
1465 | { | |
1466 | if (!*non_constant_p && !reduced_constant_expression_p (t)) | |
1467 | { | |
1468 | if (!allow_non_constant) | |
1469 | error ("%q+E is not a constant expression", t); | |
1470 | *non_constant_p = true; | |
1471 | } | |
1472 | if (TREE_OVERFLOW_P (t)) | |
1473 | { | |
1474 | if (!allow_non_constant) | |
1475 | { | |
1476 | permerror (input_location, "overflow in constant expression"); | |
1477 | /* If we're being permissive (and are in an enforcing | |
1478 | context), ignore the overflow. */ | |
1479 | if (flag_permissive) | |
1480 | return *non_constant_p; | |
1481 | } | |
1482 | *overflow_p = true; | |
1483 | } | |
1484 | return *non_constant_p; | |
1485 | } | |
1486 | ||
2b035ffe | 1487 | /* Check whether the shift operation with code CODE and type TYPE on LHS |
1488 | and RHS is undefined. If it is, give an error with an explanation, | |
1489 | and return true; return false otherwise. */ | |
1490 | ||
1491 | static bool | |
1492 | cxx_eval_check_shift_p (location_t loc, const constexpr_ctx *ctx, | |
1493 | enum tree_code code, tree type, tree lhs, tree rhs) | |
1494 | { | |
1495 | if ((code != LSHIFT_EXPR && code != RSHIFT_EXPR) | |
1496 | || TREE_CODE (lhs) != INTEGER_CST | |
1497 | || TREE_CODE (rhs) != INTEGER_CST) | |
1498 | return false; | |
1499 | ||
1500 | tree lhstype = TREE_TYPE (lhs); | |
1501 | unsigned HOST_WIDE_INT uprec = TYPE_PRECISION (TREE_TYPE (lhs)); | |
1502 | ||
1503 | /* [expr.shift] The behavior is undefined if the right operand | |
1504 | is negative, or greater than or equal to the length in bits | |
1505 | of the promoted left operand. */ | |
1506 | if (tree_int_cst_sgn (rhs) == -1) | |
1507 | { | |
1508 | if (!ctx->quiet) | |
1509 | error_at (loc, "right operand of shift expression %q+E is negative", | |
1510 | build2_loc (loc, code, type, lhs, rhs)); | |
1511 | return true; | |
1512 | } | |
1513 | if (compare_tree_int (rhs, uprec) >= 0) | |
1514 | { | |
1515 | if (!ctx->quiet) | |
1516 | error_at (loc, "right operand of shift expression %q+E is >= than " | |
1517 | "the precision of the left operand", | |
1518 | build2_loc (loc, code, type, lhs, rhs)); | |
1519 | return true; | |
1520 | } | |
1521 | ||
1522 | /* The value of E1 << E2 is E1 left-shifted E2 bit positions; [...] | |
1523 | if E1 has a signed type and non-negative value, and E1x2^E2 is | |
1524 | representable in the corresponding unsigned type of the result type, | |
1525 | then that value, converted to the result type, is the resulting value; | |
1526 | otherwise, the behavior is undefined. */ | |
1527 | if (code == LSHIFT_EXPR && !TYPE_UNSIGNED (lhstype) | |
1528 | && (cxx_dialect >= cxx11)) | |
1529 | { | |
1530 | if (tree_int_cst_sgn (lhs) == -1) | |
1531 | { | |
1532 | if (!ctx->quiet) | |
1533 | error_at (loc, "left operand of shift expression %q+E is negative", | |
1534 | build2_loc (loc, code, type, lhs, rhs)); | |
1535 | return true; | |
1536 | } | |
1537 | /* For signed x << y the following: | |
1538 | (unsigned) x >> ((prec (lhs) - 1) - y) | |
1539 | if > 1, is undefined. The right-hand side of this formula | |
1540 | is the highest bit of the LHS that can be set (starting from 0), | |
1541 | so that the shift doesn't overflow. We then right-shift the LHS | |
1542 | to see whether any other bit is set making the original shift | |
1543 | undefined -- the result is not representable in the corresponding | |
1544 | unsigned type. */ | |
1545 | tree t = build_int_cst (unsigned_type_node, uprec - 1); | |
1546 | t = fold_build2 (MINUS_EXPR, unsigned_type_node, t, rhs); | |
1547 | tree ulhs = fold_convert (unsigned_type_for (lhstype), lhs); | |
1548 | t = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ulhs), ulhs, t); | |
1549 | if (tree_int_cst_lt (integer_one_node, t)) | |
1550 | { | |
1551 | if (!ctx->quiet) | |
1552 | error_at (loc, "shift expression %q+E overflows", | |
1553 | build2_loc (loc, code, type, lhs, rhs)); | |
1554 | return true; | |
1555 | } | |
1556 | } | |
1557 | return false; | |
1558 | } | |
1559 | ||
09b42213 | 1560 | /* Subroutine of cxx_eval_constant_expression. |
1561 | Attempt to reduce the unary expression tree T to a compile time value. | |
1562 | If successful, return the value. Otherwise issue a diagnostic | |
1563 | and return error_mark_node. */ | |
1564 | ||
1565 | static tree | |
cf72f34d | 1566 | cxx_eval_unary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 1567 | bool /*lval*/, |
09b42213 | 1568 | bool *non_constant_p, bool *overflow_p) |
1569 | { | |
1570 | tree r; | |
1571 | tree orig_arg = TREE_OPERAND (t, 0); | |
c8f6aeb1 | 1572 | tree arg = cxx_eval_constant_expression (ctx, orig_arg, /*lval*/false, |
1573 | non_constant_p, overflow_p); | |
09b42213 | 1574 | VERIFY_CONSTANT (arg); |
93add516 | 1575 | location_t loc = EXPR_LOCATION (t); |
1576 | enum tree_code code = TREE_CODE (t); | |
1577 | tree type = TREE_TYPE (t); | |
1578 | r = fold_unary_loc (loc, code, type, arg); | |
1579 | if (r == NULL_TREE) | |
1580 | { | |
1581 | if (arg == orig_arg) | |
1582 | r = t; | |
1583 | else | |
1584 | r = build1_loc (loc, code, type, arg); | |
1585 | } | |
09b42213 | 1586 | VERIFY_CONSTANT (r); |
1587 | return r; | |
1588 | } | |
1589 | ||
1590 | /* Subroutine of cxx_eval_constant_expression. | |
1591 | Like cxx_eval_unary_expression, except for binary expressions. */ | |
1592 | ||
1593 | static tree | |
cf72f34d | 1594 | cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 1595 | bool /*lval*/, |
09b42213 | 1596 | bool *non_constant_p, bool *overflow_p) |
1597 | { | |
1598 | tree r; | |
1599 | tree orig_lhs = TREE_OPERAND (t, 0); | |
1600 | tree orig_rhs = TREE_OPERAND (t, 1); | |
1601 | tree lhs, rhs; | |
c8f6aeb1 | 1602 | lhs = cxx_eval_constant_expression (ctx, orig_lhs, /*lval*/false, |
b2a43197 | 1603 | non_constant_p, overflow_p); |
35f2c28f | 1604 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
1605 | a local array in a constexpr function. */ | |
1606 | bool ptr = POINTER_TYPE_P (TREE_TYPE (lhs)); | |
1607 | if (!ptr) | |
1608 | VERIFY_CONSTANT (lhs); | |
c8f6aeb1 | 1609 | rhs = cxx_eval_constant_expression (ctx, orig_rhs, /*lval*/false, |
b2a43197 | 1610 | non_constant_p, overflow_p); |
35f2c28f | 1611 | if (!ptr) |
aae7465c | 1612 | VERIFY_CONSTANT (rhs); |
93add516 | 1613 | |
1614 | location_t loc = EXPR_LOCATION (t); | |
1615 | enum tree_code code = TREE_CODE (t); | |
1616 | tree type = TREE_TYPE (t); | |
1617 | r = fold_binary_loc (loc, code, type, lhs, rhs); | |
1618 | if (r == NULL_TREE) | |
1619 | { | |
1620 | if (lhs == orig_lhs && rhs == orig_rhs) | |
1621 | r = t; | |
1622 | else | |
1623 | r = build2_loc (loc, code, type, lhs, rhs); | |
1624 | } | |
2b035ffe | 1625 | else if (cxx_eval_check_shift_p (loc, ctx, code, type, lhs, rhs)) |
1626 | *non_constant_p = true; | |
35f2c28f | 1627 | if (!ptr) |
aae7465c | 1628 | VERIFY_CONSTANT (r); |
09b42213 | 1629 | return r; |
1630 | } | |
1631 | ||
1632 | /* Subroutine of cxx_eval_constant_expression. | |
1633 | Attempt to evaluate condition expressions. Dead branches are not | |
1634 | looked into. */ | |
1635 | ||
1636 | static tree | |
cf72f34d | 1637 | cxx_eval_conditional_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1638 | bool lval, |
00f21715 | 1639 | bool *non_constant_p, bool *overflow_p, |
1640 | tree *jump_target) | |
09b42213 | 1641 | { |
cf72f34d | 1642 | tree val = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
c8f6aeb1 | 1643 | /*lval*/false, |
b2a43197 | 1644 | non_constant_p, overflow_p); |
09b42213 | 1645 | VERIFY_CONSTANT (val); |
1646 | /* Don't VERIFY_CONSTANT the other operands. */ | |
1647 | if (integer_zerop (val)) | |
cf72f34d | 1648 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), |
1227ba74 | 1649 | lval, |
00f21715 | 1650 | non_constant_p, overflow_p, |
1651 | jump_target); | |
cf72f34d | 1652 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 1653 | lval, |
00f21715 | 1654 | non_constant_p, overflow_p, |
1655 | jump_target); | |
09b42213 | 1656 | } |
1657 | ||
1658 | /* Subroutine of cxx_eval_constant_expression. | |
1659 | Attempt to reduce a reference to an array slot. */ | |
1660 | ||
1661 | static tree | |
cf72f34d | 1662 | cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1663 | bool lval, |
09b42213 | 1664 | bool *non_constant_p, bool *overflow_p) |
1665 | { | |
1666 | tree oldary = TREE_OPERAND (t, 0); | |
cf72f34d | 1667 | tree ary = cxx_eval_constant_expression (ctx, oldary, |
1227ba74 | 1668 | lval, |
b2a43197 | 1669 | non_constant_p, overflow_p); |
09b42213 | 1670 | tree index, oldidx; |
1671 | HOST_WIDE_INT i; | |
1672 | tree elem_type; | |
1673 | unsigned len, elem_nchars = 1; | |
1674 | if (*non_constant_p) | |
1675 | return t; | |
1676 | oldidx = TREE_OPERAND (t, 1); | |
cf72f34d | 1677 | index = cxx_eval_constant_expression (ctx, oldidx, |
f83e6885 | 1678 | false, |
b2a43197 | 1679 | non_constant_p, overflow_p); |
09b42213 | 1680 | VERIFY_CONSTANT (index); |
1227ba74 | 1681 | if (lval && ary == oldary && index == oldidx) |
09b42213 | 1682 | return t; |
1227ba74 | 1683 | else if (lval) |
09b42213 | 1684 | return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL); |
1685 | elem_type = TREE_TYPE (TREE_TYPE (ary)); | |
1686 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
1687 | len = CONSTRUCTOR_NELTS (ary); | |
1688 | else if (TREE_CODE (ary) == STRING_CST) | |
1689 | { | |
1690 | elem_nchars = (TYPE_PRECISION (elem_type) | |
1691 | / TYPE_PRECISION (char_type_node)); | |
1692 | len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars; | |
1693 | } | |
1694 | else | |
1695 | { | |
1696 | /* We can't do anything with other tree codes, so use | |
1697 | VERIFY_CONSTANT to complain and fail. */ | |
1698 | VERIFY_CONSTANT (ary); | |
1699 | gcc_unreachable (); | |
1700 | } | |
1701 | if (compare_tree_int (index, len) >= 0) | |
1702 | { | |
1703 | if (tree_int_cst_lt (index, array_type_nelts_top (TREE_TYPE (ary)))) | |
1704 | { | |
1705 | /* If it's within the array bounds but doesn't have an explicit | |
1706 | initializer, it's value-initialized. */ | |
1707 | tree val = build_value_init (elem_type, tf_warning_or_error); | |
cf72f34d | 1708 | return cxx_eval_constant_expression (ctx, val, |
1227ba74 | 1709 | lval, |
b2a43197 | 1710 | non_constant_p, overflow_p); |
09b42213 | 1711 | } |
1712 | ||
f83e6885 | 1713 | if (!ctx->quiet) |
09b42213 | 1714 | error ("array subscript out of bound"); |
1715 | *non_constant_p = true; | |
1716 | return t; | |
1717 | } | |
1718 | else if (tree_int_cst_lt (index, integer_zero_node)) | |
1719 | { | |
f83e6885 | 1720 | if (!ctx->quiet) |
09b42213 | 1721 | error ("negative array subscript"); |
1722 | *non_constant_p = true; | |
1723 | return t; | |
1724 | } | |
1725 | i = tree_to_shwi (index); | |
1726 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
1727 | return (*CONSTRUCTOR_ELTS (ary))[i].value; | |
1728 | else if (elem_nchars == 1) | |
1729 | return build_int_cst (cv_unqualified (TREE_TYPE (TREE_TYPE (ary))), | |
1730 | TREE_STRING_POINTER (ary)[i]); | |
1731 | else | |
1732 | { | |
1733 | tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (ary))); | |
1734 | return native_interpret_expr (type, (const unsigned char *) | |
1735 | TREE_STRING_POINTER (ary) | |
1736 | + i * elem_nchars, elem_nchars); | |
1737 | } | |
1738 | /* Don't VERIFY_CONSTANT here. */ | |
1739 | } | |
1740 | ||
1741 | /* Subroutine of cxx_eval_constant_expression. | |
1742 | Attempt to reduce a field access of a value of class type. */ | |
1743 | ||
1744 | static tree | |
cf72f34d | 1745 | cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1746 | bool lval, |
09b42213 | 1747 | bool *non_constant_p, bool *overflow_p) |
1748 | { | |
1749 | unsigned HOST_WIDE_INT i; | |
1750 | tree field; | |
1751 | tree value; | |
1752 | tree part = TREE_OPERAND (t, 1); | |
1753 | tree orig_whole = TREE_OPERAND (t, 0); | |
cf72f34d | 1754 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 1755 | lval, |
b2a43197 | 1756 | non_constant_p, overflow_p); |
09b42213 | 1757 | if (whole == orig_whole) |
1758 | return t; | |
1227ba74 | 1759 | if (lval) |
09b42213 | 1760 | return fold_build3 (COMPONENT_REF, TREE_TYPE (t), |
1761 | whole, part, NULL_TREE); | |
1762 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
1763 | CONSTRUCTOR. */ | |
1764 | if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR) | |
1765 | { | |
f83e6885 | 1766 | if (!ctx->quiet) |
09b42213 | 1767 | error ("%qE is not a constant expression", orig_whole); |
1768 | *non_constant_p = true; | |
1769 | } | |
1770 | if (DECL_MUTABLE_P (part)) | |
1771 | { | |
f83e6885 | 1772 | if (!ctx->quiet) |
09b42213 | 1773 | error ("mutable %qD is not usable in a constant expression", part); |
1774 | *non_constant_p = true; | |
1775 | } | |
1776 | if (*non_constant_p) | |
1777 | return t; | |
1778 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
1779 | { | |
1780 | if (field == part) | |
9c96033c | 1781 | { |
1782 | if (value) | |
1783 | return value; | |
1784 | else | |
1785 | /* We're in the middle of initializing it. */ | |
1786 | break; | |
1787 | } | |
09b42213 | 1788 | } |
1789 | if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE | |
1790 | && CONSTRUCTOR_NELTS (whole) > 0) | |
1791 | { | |
1792 | /* DR 1188 says we don't have to deal with this. */ | |
f83e6885 | 1793 | if (!ctx->quiet) |
09b42213 | 1794 | error ("accessing %qD member instead of initialized %qD member in " |
1795 | "constant expression", part, CONSTRUCTOR_ELT (whole, 0)->index); | |
1796 | *non_constant_p = true; | |
1797 | return t; | |
1798 | } | |
1799 | ||
cf72f34d | 1800 | if (CONSTRUCTOR_NO_IMPLICIT_ZERO (whole)) |
1801 | { | |
1802 | /* 'whole' is part of the aggregate initializer we're currently | |
1803 | building; if there's no initializer for this member yet, that's an | |
1804 | error. */ | |
f83e6885 | 1805 | if (!ctx->quiet) |
cf72f34d | 1806 | error ("accessing uninitialized member %qD", part); |
1807 | *non_constant_p = true; | |
1808 | return t; | |
1809 | } | |
1810 | ||
09b42213 | 1811 | /* If there's no explicit init for this field, it's value-initialized. */ |
1812 | value = build_value_init (TREE_TYPE (t), tf_warning_or_error); | |
cf72f34d | 1813 | return cxx_eval_constant_expression (ctx, value, |
1227ba74 | 1814 | lval, |
b2a43197 | 1815 | non_constant_p, overflow_p); |
09b42213 | 1816 | } |
1817 | ||
1818 | /* Subroutine of cxx_eval_constant_expression. | |
1819 | Attempt to reduce a field access of a value of class type that is | |
1820 | expressed as a BIT_FIELD_REF. */ | |
1821 | ||
1822 | static tree | |
cf72f34d | 1823 | cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1824 | bool lval, |
09b42213 | 1825 | bool *non_constant_p, bool *overflow_p) |
1826 | { | |
1827 | tree orig_whole = TREE_OPERAND (t, 0); | |
1828 | tree retval, fldval, utype, mask; | |
1829 | bool fld_seen = false; | |
1830 | HOST_WIDE_INT istart, isize; | |
cf72f34d | 1831 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 1832 | lval, |
b2a43197 | 1833 | non_constant_p, overflow_p); |
09b42213 | 1834 | tree start, field, value; |
1835 | unsigned HOST_WIDE_INT i; | |
1836 | ||
1837 | if (whole == orig_whole) | |
1838 | return t; | |
1839 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
1840 | CONSTRUCTOR. */ | |
1841 | if (!*non_constant_p | |
1842 | && TREE_CODE (whole) != VECTOR_CST | |
1843 | && TREE_CODE (whole) != CONSTRUCTOR) | |
1844 | { | |
f83e6885 | 1845 | if (!ctx->quiet) |
09b42213 | 1846 | error ("%qE is not a constant expression", orig_whole); |
1847 | *non_constant_p = true; | |
1848 | } | |
1849 | if (*non_constant_p) | |
1850 | return t; | |
1851 | ||
1852 | if (TREE_CODE (whole) == VECTOR_CST) | |
1853 | return fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole, | |
1854 | TREE_OPERAND (t, 1), TREE_OPERAND (t, 2)); | |
1855 | ||
1856 | start = TREE_OPERAND (t, 2); | |
1857 | istart = tree_to_shwi (start); | |
1858 | isize = tree_to_shwi (TREE_OPERAND (t, 1)); | |
1859 | utype = TREE_TYPE (t); | |
1860 | if (!TYPE_UNSIGNED (utype)) | |
1861 | utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1); | |
1862 | retval = build_int_cst (utype, 0); | |
1863 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
1864 | { | |
1865 | tree bitpos = bit_position (field); | |
1866 | if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1)) | |
1867 | return value; | |
1868 | if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE | |
1869 | && TREE_CODE (value) == INTEGER_CST | |
1870 | && tree_fits_shwi_p (bitpos) | |
1871 | && tree_fits_shwi_p (DECL_SIZE (field))) | |
1872 | { | |
1873 | HOST_WIDE_INT bit = tree_to_shwi (bitpos); | |
1874 | HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field)); | |
1875 | HOST_WIDE_INT shift; | |
1876 | if (bit >= istart && bit + sz <= istart + isize) | |
1877 | { | |
1878 | fldval = fold_convert (utype, value); | |
1879 | mask = build_int_cst_type (utype, -1); | |
1880 | mask = fold_build2 (LSHIFT_EXPR, utype, mask, | |
1881 | size_int (TYPE_PRECISION (utype) - sz)); | |
1882 | mask = fold_build2 (RSHIFT_EXPR, utype, mask, | |
1883 | size_int (TYPE_PRECISION (utype) - sz)); | |
1884 | fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask); | |
1885 | shift = bit - istart; | |
1886 | if (BYTES_BIG_ENDIAN) | |
1887 | shift = TYPE_PRECISION (utype) - shift - sz; | |
1888 | fldval = fold_build2 (LSHIFT_EXPR, utype, fldval, | |
1889 | size_int (shift)); | |
1890 | retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval); | |
1891 | fld_seen = true; | |
1892 | } | |
1893 | } | |
1894 | } | |
1895 | if (fld_seen) | |
1896 | return fold_convert (TREE_TYPE (t), retval); | |
1897 | gcc_unreachable (); | |
1898 | return error_mark_node; | |
1899 | } | |
1900 | ||
1901 | /* Subroutine of cxx_eval_constant_expression. | |
1902 | Evaluate a short-circuited logical expression T in the context | |
1903 | of a given constexpr CALL. BAILOUT_VALUE is the value for | |
1904 | early return. CONTINUE_VALUE is used here purely for | |
1905 | sanity check purposes. */ | |
1906 | ||
1907 | static tree | |
cf72f34d | 1908 | cxx_eval_logical_expression (const constexpr_ctx *ctx, tree t, |
09b42213 | 1909 | tree bailout_value, tree continue_value, |
1227ba74 | 1910 | bool lval, |
09b42213 | 1911 | bool *non_constant_p, bool *overflow_p) |
1912 | { | |
1913 | tree r; | |
cf72f34d | 1914 | tree lhs = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 1915 | lval, |
b2a43197 | 1916 | non_constant_p, overflow_p); |
09b42213 | 1917 | VERIFY_CONSTANT (lhs); |
1918 | if (tree_int_cst_equal (lhs, bailout_value)) | |
1919 | return lhs; | |
1920 | gcc_assert (tree_int_cst_equal (lhs, continue_value)); | |
cf72f34d | 1921 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 1922 | lval, non_constant_p, |
b2a43197 | 1923 | overflow_p); |
09b42213 | 1924 | VERIFY_CONSTANT (r); |
1925 | return r; | |
1926 | } | |
1927 | ||
1928 | /* REF is a COMPONENT_REF designating a particular field. V is a vector of | |
1929 | CONSTRUCTOR elements to initialize (part of) an object containing that | |
1930 | field. Return a pointer to the constructor_elt corresponding to the | |
1931 | initialization of the field. */ | |
1932 | ||
1933 | static constructor_elt * | |
1934 | base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref) | |
1935 | { | |
1936 | tree aggr = TREE_OPERAND (ref, 0); | |
1937 | tree field = TREE_OPERAND (ref, 1); | |
1938 | HOST_WIDE_INT i; | |
1939 | constructor_elt *ce; | |
1940 | ||
1941 | gcc_assert (TREE_CODE (ref) == COMPONENT_REF); | |
1942 | ||
1943 | if (TREE_CODE (aggr) == COMPONENT_REF) | |
1944 | { | |
1945 | constructor_elt *base_ce | |
1946 | = base_field_constructor_elt (v, aggr); | |
1947 | v = CONSTRUCTOR_ELTS (base_ce->value); | |
1948 | } | |
1949 | ||
1950 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
1951 | if (ce->index == field) | |
1952 | return ce; | |
1953 | ||
1954 | gcc_unreachable (); | |
1955 | return NULL; | |
1956 | } | |
1957 | ||
cf72f34d | 1958 | /* Some of the expressions fed to the constexpr mechanism are calls to |
1959 | constructors, which have type void. In that case, return the type being | |
1960 | initialized by the constructor. */ | |
1961 | ||
1962 | static tree | |
1963 | initialized_type (tree t) | |
1964 | { | |
1965 | if (TYPE_P (t)) | |
1966 | return t; | |
1967 | tree type = cv_unqualified (TREE_TYPE (t)); | |
1968 | if (TREE_CODE (t) == CALL_EXPR || TREE_CODE (t) == AGGR_INIT_EXPR) | |
1969 | { | |
1970 | /* A constructor call has void type, so we need to look deeper. */ | |
1971 | tree fn = get_function_named_in_call (t); | |
1972 | if (fn && TREE_CODE (fn) == FUNCTION_DECL | |
1973 | && DECL_CXX_CONSTRUCTOR_P (fn)) | |
1974 | type = DECL_CONTEXT (fn); | |
1975 | } | |
1976 | return type; | |
1977 | } | |
1978 | ||
1979 | /* We're about to initialize element INDEX of an array or class from VALUE. | |
1980 | Set up NEW_CTX appropriately by adjusting .object to refer to the | |
1981 | subobject and creating a new CONSTRUCTOR if the element is itself | |
1982 | a class or array. */ | |
1983 | ||
1984 | static void | |
1985 | init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, | |
1986 | tree index, tree &value) | |
1987 | { | |
1988 | new_ctx = *ctx; | |
1989 | ||
1990 | if (index && TREE_CODE (index) != INTEGER_CST | |
1991 | && TREE_CODE (index) != FIELD_DECL) | |
1992 | /* This won't have an element in the new CONSTRUCTOR. */ | |
1993 | return; | |
1994 | ||
1995 | tree type = initialized_type (value); | |
1996 | if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) | |
1997 | /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ | |
1998 | return; | |
1999 | ||
2000 | /* The sub-aggregate initializer might contain a placeholder; | |
2001 | update object to refer to the subobject and ctor to refer to | |
2002 | the (newly created) sub-initializer. */ | |
2003 | if (ctx->object) | |
2004 | new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); | |
2005 | tree elt = build_constructor (type, NULL); | |
2006 | CONSTRUCTOR_NO_IMPLICIT_ZERO (elt) = true; | |
2007 | new_ctx.ctor = elt; | |
2008 | ||
2009 | if (TREE_CODE (value) == TARGET_EXPR) | |
2010 | /* Avoid creating another CONSTRUCTOR when we expand the TARGET_EXPR. */ | |
2011 | value = TARGET_EXPR_INITIAL (value); | |
2012 | } | |
2013 | ||
2014 | /* We're about to process an initializer for a class or array TYPE. Make | |
2015 | sure that CTX is set up appropriately. */ | |
2016 | ||
2017 | static void | |
2018 | verify_ctor_sanity (const constexpr_ctx *ctx, tree type) | |
2019 | { | |
2020 | /* We don't bother building a ctor for an empty base subobject. */ | |
2021 | if (is_empty_class (type)) | |
2022 | return; | |
2023 | ||
2024 | /* We're in the middle of an initializer that might involve placeholders; | |
2025 | our caller should have created a CONSTRUCTOR for us to put the | |
2026 | initializer into. We will either return that constructor or T. */ | |
2027 | gcc_assert (ctx->ctor); | |
2028 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2029 | (type, TREE_TYPE (ctx->ctor))); | |
2030 | gcc_assert (CONSTRUCTOR_NELTS (ctx->ctor) == 0); | |
2031 | if (ctx->object) | |
2032 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2033 | (type, TREE_TYPE (ctx->object))); | |
2034 | gcc_assert (!ctx->object || !DECL_P (ctx->object) | |
2035 | || *(ctx->values->get (ctx->object)) == ctx->ctor); | |
2036 | } | |
2037 | ||
09b42213 | 2038 | /* Subroutine of cxx_eval_constant_expression. |
2039 | The expression tree T denotes a C-style array or a C-style | |
2040 | aggregate. Reduce it to a constant expression. */ | |
2041 | ||
2042 | static tree | |
cf72f34d | 2043 | cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2044 | bool lval, |
09b42213 | 2045 | bool *non_constant_p, bool *overflow_p) |
2046 | { | |
2047 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
09b42213 | 2048 | bool changed = false; |
2049 | gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t)); | |
cf72f34d | 2050 | |
2051 | verify_ctor_sanity (ctx, TREE_TYPE (t)); | |
2052 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
2053 | vec_alloc (*p, vec_safe_length (v)); | |
2054 | ||
2055 | unsigned i; tree index, value; | |
2056 | FOR_EACH_CONSTRUCTOR_ELT (v, i, index, value) | |
09b42213 | 2057 | { |
cf72f34d | 2058 | constexpr_ctx new_ctx; |
2059 | init_subob_ctx (ctx, new_ctx, index, value); | |
2060 | if (new_ctx.ctor != ctx->ctor) | |
2061 | /* If we built a new CONSTRUCTOR, attach it now so that other | |
2062 | initializers can refer to it. */ | |
2063 | CONSTRUCTOR_APPEND_ELT (*p, index, new_ctx.ctor); | |
2064 | tree elt = cxx_eval_constant_expression (&new_ctx, value, | |
1227ba74 | 2065 | lval, |
b2a43197 | 2066 | non_constant_p, overflow_p); |
09b42213 | 2067 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 2068 | if (ctx->quiet && *non_constant_p) |
cf72f34d | 2069 | break; |
2070 | if (elt != value) | |
09b42213 | 2071 | changed = true; |
cf72f34d | 2072 | if (index && TREE_CODE (index) == COMPONENT_REF) |
09b42213 | 2073 | { |
2074 | /* This is an initialization of a vfield inside a base | |
2075 | subaggregate that we already initialized; push this | |
2076 | initialization into the previous initialization. */ | |
cf72f34d | 2077 | constructor_elt *inner = base_field_constructor_elt (*p, index); |
09b42213 | 2078 | inner->value = elt; |
cf72f34d | 2079 | changed = true; |
09b42213 | 2080 | } |
cf72f34d | 2081 | else if (index |
2082 | && (TREE_CODE (index) == NOP_EXPR | |
2083 | || TREE_CODE (index) == POINTER_PLUS_EXPR)) | |
09b42213 | 2084 | { |
2085 | /* This is an initializer for an empty base; now that we've | |
2086 | checked that it's constant, we can ignore it. */ | |
cf72f34d | 2087 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (index)))); |
2088 | changed = true; | |
2089 | } | |
2090 | else if (new_ctx.ctor != ctx->ctor) | |
2091 | { | |
2092 | /* We appended this element above; update the value. */ | |
2093 | gcc_assert ((*p)->last().index == index); | |
2094 | (*p)->last().value = elt; | |
09b42213 | 2095 | } |
2096 | else | |
cf72f34d | 2097 | CONSTRUCTOR_APPEND_ELT (*p, index, elt); |
09b42213 | 2098 | } |
2099 | if (*non_constant_p || !changed) | |
cf72f34d | 2100 | return t; |
2101 | t = ctx->ctor; | |
2102 | /* We're done building this CONSTRUCTOR, so now we can interpret an | |
2103 | element without an explicit initializer as value-initialized. */ | |
2104 | CONSTRUCTOR_NO_IMPLICIT_ZERO (t) = false; | |
09b42213 | 2105 | if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE) |
2106 | t = fold (t); | |
2107 | return t; | |
2108 | } | |
2109 | ||
2110 | /* Subroutine of cxx_eval_constant_expression. | |
2111 | The expression tree T is a VEC_INIT_EXPR which denotes the desired | |
2112 | initialization of a non-static data member of array type. Reduce it to a | |
2113 | CONSTRUCTOR. | |
2114 | ||
2115 | Note that apart from value-initialization (when VALUE_INIT is true), | |
2116 | this is only intended to support value-initialization and the | |
2117 | initializations done by defaulted constructors for classes with | |
2118 | non-static data members of array type. In this case, VEC_INIT_EXPR_INIT | |
2119 | will either be NULL_TREE for the default constructor, or a COMPONENT_REF | |
2120 | for the copy/move constructor. */ | |
2121 | ||
2122 | static tree | |
cf72f34d | 2123 | cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, |
1227ba74 | 2124 | bool value_init, bool lval, |
09b42213 | 2125 | bool *non_constant_p, bool *overflow_p) |
2126 | { | |
2127 | tree elttype = TREE_TYPE (atype); | |
3e520b97 | 2128 | unsigned HOST_WIDE_INT max = tree_to_uhwi (array_type_nelts_top (atype)); |
cf72f34d | 2129 | verify_ctor_sanity (ctx, atype); |
2130 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
2131 | vec_alloc (*p, max + 1); | |
09b42213 | 2132 | bool pre_init = false; |
3e520b97 | 2133 | unsigned HOST_WIDE_INT i; |
09b42213 | 2134 | |
2135 | /* For the default constructor, build up a call to the default | |
2136 | constructor of the element type. We only need to handle class types | |
2137 | here, as for a constructor to be constexpr, all members must be | |
2138 | initialized, which for a defaulted default constructor means they must | |
2139 | be of a class type with a constexpr default constructor. */ | |
2140 | if (TREE_CODE (elttype) == ARRAY_TYPE) | |
2141 | /* We only do this at the lowest level. */; | |
2142 | else if (value_init) | |
2143 | { | |
2144 | init = build_value_init (elttype, tf_warning_or_error); | |
09b42213 | 2145 | pre_init = true; |
2146 | } | |
2147 | else if (!init) | |
2148 | { | |
2149 | vec<tree, va_gc> *argvec = make_tree_vector (); | |
2150 | init = build_special_member_call (NULL_TREE, complete_ctor_identifier, | |
2151 | &argvec, elttype, LOOKUP_NORMAL, | |
2152 | tf_warning_or_error); | |
2153 | release_tree_vector (argvec); | |
9c96033c | 2154 | init = build_aggr_init_expr (TREE_TYPE (init), init); |
09b42213 | 2155 | pre_init = true; |
2156 | } | |
2157 | ||
3e520b97 | 2158 | for (i = 0; i < max; ++i) |
09b42213 | 2159 | { |
2160 | tree idx = build_int_cst (size_type_node, i); | |
2161 | tree eltinit; | |
cf72f34d | 2162 | constexpr_ctx new_ctx; |
2163 | init_subob_ctx (ctx, new_ctx, idx, pre_init ? init : elttype); | |
2164 | if (new_ctx.ctor != ctx->ctor) | |
2165 | CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor); | |
09b42213 | 2166 | if (TREE_CODE (elttype) == ARRAY_TYPE) |
2167 | { | |
2168 | /* A multidimensional array; recurse. */ | |
2169 | if (value_init || init == NULL_TREE) | |
2170 | eltinit = NULL_TREE; | |
2171 | else | |
2172 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2173 | tf_warning_or_error); | |
cf72f34d | 2174 | eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, value_init, |
1227ba74 | 2175 | lval, |
09b42213 | 2176 | non_constant_p, overflow_p); |
2177 | } | |
2178 | else if (pre_init) | |
2179 | { | |
2180 | /* Initializing an element using value or default initialization | |
2181 | we just pre-built above. */ | |
cf72f34d | 2182 | eltinit = (cxx_eval_constant_expression |
f83e6885 | 2183 | (&new_ctx, init, |
1227ba74 | 2184 | lval, non_constant_p, overflow_p)); |
09b42213 | 2185 | } |
2186 | else | |
2187 | { | |
2188 | /* Copying an element. */ | |
2189 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2190 | (atype, TREE_TYPE (init))); | |
2191 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2192 | tf_warning_or_error); | |
2193 | if (!real_lvalue_p (init)) | |
2194 | eltinit = move (eltinit); | |
2195 | eltinit = force_rvalue (eltinit, tf_warning_or_error); | |
cf72f34d | 2196 | eltinit = (cxx_eval_constant_expression |
1227ba74 | 2197 | (&new_ctx, eltinit, lval, |
b2a43197 | 2198 | non_constant_p, overflow_p)); |
09b42213 | 2199 | } |
f83e6885 | 2200 | if (*non_constant_p && !ctx->quiet) |
cf72f34d | 2201 | break; |
2202 | if (new_ctx.ctor != ctx->ctor) | |
2203 | { | |
2204 | /* We appended this element above; update the value. */ | |
2205 | gcc_assert ((*p)->last().index == idx); | |
2206 | (*p)->last().value = eltinit; | |
2207 | } | |
2208 | else | |
2209 | CONSTRUCTOR_APPEND_ELT (*p, idx, eltinit); | |
09b42213 | 2210 | } |
2211 | ||
2212 | if (!*non_constant_p) | |
2213 | { | |
cf72f34d | 2214 | init = ctx->ctor; |
2215 | CONSTRUCTOR_NO_IMPLICIT_ZERO (init) = false; | |
09b42213 | 2216 | } |
09b42213 | 2217 | return init; |
2218 | } | |
2219 | ||
2220 | static tree | |
cf72f34d | 2221 | cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2222 | bool lval, |
09b42213 | 2223 | bool *non_constant_p, bool *overflow_p) |
2224 | { | |
2225 | tree atype = TREE_TYPE (t); | |
2226 | tree init = VEC_INIT_EXPR_INIT (t); | |
cf72f34d | 2227 | tree r = cxx_eval_vec_init_1 (ctx, atype, init, |
09b42213 | 2228 | VEC_INIT_EXPR_VALUE_INIT (t), |
1227ba74 | 2229 | lval, non_constant_p, overflow_p); |
09b42213 | 2230 | if (*non_constant_p) |
2231 | return t; | |
2232 | else | |
2233 | return r; | |
2234 | } | |
2235 | ||
2236 | /* A less strict version of fold_indirect_ref_1, which requires cv-quals to | |
2237 | match. We want to be less strict for simple *& folding; if we have a | |
2238 | non-const temporary that we access through a const pointer, that should | |
2239 | work. We handle this here rather than change fold_indirect_ref_1 | |
2240 | because we're dealing with things like ADDR_EXPR of INTEGER_CST which | |
2241 | don't really make sense outside of constant expression evaluation. Also | |
2242 | we want to allow folding to COMPONENT_REF, which could cause trouble | |
2243 | with TBAA in fold_indirect_ref_1. | |
2244 | ||
2245 | Try to keep this function synced with fold_indirect_ref_1. */ | |
2246 | ||
2247 | static tree | |
2248 | cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) | |
2249 | { | |
2250 | tree sub, subtype; | |
2251 | ||
2252 | sub = op0; | |
2253 | STRIP_NOPS (sub); | |
2254 | subtype = TREE_TYPE (sub); | |
2255 | if (!POINTER_TYPE_P (subtype)) | |
2256 | return NULL_TREE; | |
2257 | ||
2258 | if (TREE_CODE (sub) == ADDR_EXPR) | |
2259 | { | |
2260 | tree op = TREE_OPERAND (sub, 0); | |
2261 | tree optype = TREE_TYPE (op); | |
2262 | ||
2263 | /* *&CONST_DECL -> to the value of the const decl. */ | |
2264 | if (TREE_CODE (op) == CONST_DECL) | |
2265 | return DECL_INITIAL (op); | |
2266 | /* *&p => p; make sure to handle *&"str"[cst] here. */ | |
2267 | if (same_type_ignoring_top_level_qualifiers_p (optype, type)) | |
2268 | { | |
2269 | tree fop = fold_read_from_constant_string (op); | |
2270 | if (fop) | |
2271 | return fop; | |
2272 | else | |
2273 | return op; | |
2274 | } | |
2275 | /* *(foo *)&fooarray => fooarray[0] */ | |
2276 | else if (TREE_CODE (optype) == ARRAY_TYPE | |
2277 | && (same_type_ignoring_top_level_qualifiers_p | |
2278 | (type, TREE_TYPE (optype)))) | |
2279 | { | |
2280 | tree type_domain = TYPE_DOMAIN (optype); | |
2281 | tree min_val = size_zero_node; | |
2282 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
2283 | min_val = TYPE_MIN_VALUE (type_domain); | |
2284 | return build4_loc (loc, ARRAY_REF, type, op, min_val, | |
2285 | NULL_TREE, NULL_TREE); | |
2286 | } | |
2287 | /* *(foo *)&complexfoo => __real__ complexfoo */ | |
2288 | else if (TREE_CODE (optype) == COMPLEX_TYPE | |
2289 | && (same_type_ignoring_top_level_qualifiers_p | |
2290 | (type, TREE_TYPE (optype)))) | |
2291 | return fold_build1_loc (loc, REALPART_EXPR, type, op); | |
2292 | /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */ | |
2293 | else if (TREE_CODE (optype) == VECTOR_TYPE | |
2294 | && (same_type_ignoring_top_level_qualifiers_p | |
2295 | (type, TREE_TYPE (optype)))) | |
2296 | { | |
2297 | tree part_width = TYPE_SIZE (type); | |
2298 | tree index = bitsize_int (0); | |
2299 | return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, index); | |
2300 | } | |
2301 | /* Also handle conversion to an empty base class, which | |
2302 | is represented with a NOP_EXPR. */ | |
2303 | else if (is_empty_class (type) | |
2304 | && CLASS_TYPE_P (optype) | |
2305 | && DERIVED_FROM_P (type, optype)) | |
2306 | { | |
2307 | *empty_base = true; | |
2308 | return op; | |
2309 | } | |
2310 | /* *(foo *)&struct_with_foo_field => COMPONENT_REF */ | |
2311 | else if (RECORD_OR_UNION_TYPE_P (optype)) | |
2312 | { | |
2313 | tree field = TYPE_FIELDS (optype); | |
2314 | for (; field; field = DECL_CHAIN (field)) | |
2315 | if (TREE_CODE (field) == FIELD_DECL | |
2316 | && integer_zerop (byte_position (field)) | |
2317 | && (same_type_ignoring_top_level_qualifiers_p | |
2318 | (TREE_TYPE (field), type))) | |
2319 | { | |
2320 | return fold_build3 (COMPONENT_REF, type, op, field, NULL_TREE); | |
2321 | break; | |
2322 | } | |
2323 | } | |
2324 | } | |
2325 | else if (TREE_CODE (sub) == POINTER_PLUS_EXPR | |
2326 | && TREE_CODE (TREE_OPERAND (sub, 1)) == INTEGER_CST) | |
2327 | { | |
2328 | tree op00 = TREE_OPERAND (sub, 0); | |
2329 | tree op01 = TREE_OPERAND (sub, 1); | |
2330 | ||
2331 | STRIP_NOPS (op00); | |
2332 | if (TREE_CODE (op00) == ADDR_EXPR) | |
2333 | { | |
2334 | tree op00type; | |
2335 | op00 = TREE_OPERAND (op00, 0); | |
2336 | op00type = TREE_TYPE (op00); | |
2337 | ||
2338 | /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */ | |
2339 | if (TREE_CODE (op00type) == VECTOR_TYPE | |
2340 | && (same_type_ignoring_top_level_qualifiers_p | |
2341 | (type, TREE_TYPE (op00type)))) | |
2342 | { | |
2343 | HOST_WIDE_INT offset = tree_to_shwi (op01); | |
2344 | tree part_width = TYPE_SIZE (type); | |
2345 | unsigned HOST_WIDE_INT part_widthi = tree_to_shwi (part_width)/BITS_PER_UNIT; | |
2346 | unsigned HOST_WIDE_INT indexi = offset * BITS_PER_UNIT; | |
2347 | tree index = bitsize_int (indexi); | |
2348 | ||
2349 | if (offset / part_widthi < TYPE_VECTOR_SUBPARTS (op00type)) | |
2350 | return fold_build3_loc (loc, | |
2351 | BIT_FIELD_REF, type, op00, | |
2352 | part_width, index); | |
2353 | ||
2354 | } | |
2355 | /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ | |
2356 | else if (TREE_CODE (op00type) == COMPLEX_TYPE | |
2357 | && (same_type_ignoring_top_level_qualifiers_p | |
2358 | (type, TREE_TYPE (op00type)))) | |
2359 | { | |
2360 | tree size = TYPE_SIZE_UNIT (type); | |
2361 | if (tree_int_cst_equal (size, op01)) | |
2362 | return fold_build1_loc (loc, IMAGPART_EXPR, type, op00); | |
2363 | } | |
2364 | /* ((foo *)&fooarray)[1] => fooarray[1] */ | |
2365 | else if (TREE_CODE (op00type) == ARRAY_TYPE | |
2366 | && (same_type_ignoring_top_level_qualifiers_p | |
2367 | (type, TREE_TYPE (op00type)))) | |
2368 | { | |
2369 | tree type_domain = TYPE_DOMAIN (op00type); | |
2370 | tree min_val = size_zero_node; | |
2371 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
2372 | min_val = TYPE_MIN_VALUE (type_domain); | |
2373 | op01 = size_binop_loc (loc, EXACT_DIV_EXPR, op01, | |
2374 | TYPE_SIZE_UNIT (type)); | |
2375 | op01 = size_binop_loc (loc, PLUS_EXPR, op01, min_val); | |
2376 | return build4_loc (loc, ARRAY_REF, type, op00, op01, | |
2377 | NULL_TREE, NULL_TREE); | |
2378 | } | |
2379 | /* Also handle conversion to an empty base class, which | |
2380 | is represented with a NOP_EXPR. */ | |
2381 | else if (is_empty_class (type) | |
2382 | && CLASS_TYPE_P (op00type) | |
2383 | && DERIVED_FROM_P (type, op00type)) | |
2384 | { | |
2385 | *empty_base = true; | |
2386 | return op00; | |
2387 | } | |
2388 | /* ((foo *)&struct_with_foo_field)[1] => COMPONENT_REF */ | |
2389 | else if (RECORD_OR_UNION_TYPE_P (op00type)) | |
2390 | { | |
2391 | tree field = TYPE_FIELDS (op00type); | |
2392 | for (; field; field = DECL_CHAIN (field)) | |
2393 | if (TREE_CODE (field) == FIELD_DECL | |
2394 | && tree_int_cst_equal (byte_position (field), op01) | |
2395 | && (same_type_ignoring_top_level_qualifiers_p | |
2396 | (TREE_TYPE (field), type))) | |
2397 | { | |
2398 | return fold_build3 (COMPONENT_REF, type, op00, | |
2399 | field, NULL_TREE); | |
2400 | break; | |
2401 | } | |
2402 | } | |
2403 | } | |
2404 | } | |
2405 | /* *(foo *)fooarrptr => (*fooarrptr)[0] */ | |
2406 | else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE | |
2407 | && (same_type_ignoring_top_level_qualifiers_p | |
2408 | (type, TREE_TYPE (TREE_TYPE (subtype))))) | |
2409 | { | |
2410 | tree type_domain; | |
2411 | tree min_val = size_zero_node; | |
2412 | tree newsub = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL); | |
2413 | if (newsub) | |
2414 | sub = newsub; | |
2415 | else | |
2416 | sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub); | |
2417 | type_domain = TYPE_DOMAIN (TREE_TYPE (sub)); | |
2418 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
2419 | min_val = TYPE_MIN_VALUE (type_domain); | |
2420 | return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE, | |
2421 | NULL_TREE); | |
2422 | } | |
2423 | ||
2424 | return NULL_TREE; | |
2425 | } | |
2426 | ||
2427 | static tree | |
cf72f34d | 2428 | cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2429 | bool lval, |
09b42213 | 2430 | bool *non_constant_p, bool *overflow_p) |
2431 | { | |
2432 | tree orig_op0 = TREE_OPERAND (t, 0); | |
09b42213 | 2433 | bool empty_base = false; |
09b42213 | 2434 | |
7e0f3388 | 2435 | /* First try to simplify it directly. */ |
2436 | tree r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), orig_op0, | |
2437 | &empty_base); | |
2438 | if (!r) | |
09b42213 | 2439 | { |
7e0f3388 | 2440 | /* If that didn't work, evaluate the operand first. */ |
2441 | tree op0 = cxx_eval_constant_expression (ctx, orig_op0, | |
2442 | /*lval*/false, non_constant_p, | |
2443 | overflow_p); | |
2444 | /* Don't VERIFY_CONSTANT here. */ | |
2445 | if (*non_constant_p) | |
2446 | return t; | |
2447 | ||
2448 | r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), op0, | |
2449 | &empty_base); | |
2450 | if (r == NULL_TREE) | |
09b42213 | 2451 | { |
2452 | /* We couldn't fold to a constant value. Make sure it's not | |
2453 | something we should have been able to fold. */ | |
7e0f3388 | 2454 | tree sub = op0; |
2455 | STRIP_NOPS (sub); | |
2456 | if (TREE_CODE (sub) == ADDR_EXPR) | |
2457 | { | |
2458 | gcc_assert (!same_type_ignoring_top_level_qualifiers_p | |
2459 | (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t))); | |
2460 | /* DR 1188 says we don't have to deal with this. */ | |
2461 | if (!ctx->quiet) | |
2462 | error ("accessing value of %qE through a %qT glvalue in a " | |
2463 | "constant expression", build_fold_indirect_ref (sub), | |
2464 | TREE_TYPE (t)); | |
2465 | *non_constant_p = true; | |
2466 | return t; | |
2467 | } | |
2468 | ||
2469 | if (lval && op0 != orig_op0) | |
2470 | return build1 (INDIRECT_REF, TREE_TYPE (t), op0); | |
2471 | if (!lval) | |
2472 | VERIFY_CONSTANT (t); | |
09b42213 | 2473 | return t; |
2474 | } | |
2475 | } | |
2476 | ||
7e0f3388 | 2477 | r = cxx_eval_constant_expression (ctx, r, |
2478 | lval, non_constant_p, overflow_p); | |
2479 | if (*non_constant_p) | |
2480 | return t; | |
2481 | ||
09b42213 | 2482 | /* If we're pulling out the value of an empty base, make sure |
2483 | that the whole object is constant and then return an empty | |
2484 | CONSTRUCTOR. */ | |
1227ba74 | 2485 | if (empty_base && !lval) |
09b42213 | 2486 | { |
2487 | VERIFY_CONSTANT (r); | |
2488 | r = build_constructor (TREE_TYPE (t), NULL); | |
2489 | TREE_CONSTANT (r) = true; | |
2490 | } | |
2491 | ||
09b42213 | 2492 | return r; |
2493 | } | |
2494 | ||
2495 | /* Complain about R, a VAR_DECL, not being usable in a constant expression. | |
2496 | Shared between potential_constant_expression and | |
2497 | cxx_eval_constant_expression. */ | |
2498 | ||
2499 | static void | |
2500 | non_const_var_error (tree r) | |
2501 | { | |
2502 | tree type = TREE_TYPE (r); | |
2503 | error ("the value of %qD is not usable in a constant " | |
2504 | "expression", r); | |
2505 | /* Avoid error cascade. */ | |
2506 | if (DECL_INITIAL (r) == error_mark_node) | |
2507 | return; | |
2508 | if (DECL_DECLARED_CONSTEXPR_P (r)) | |
2509 | inform (DECL_SOURCE_LOCATION (r), | |
2510 | "%qD used in its own initializer", r); | |
2511 | else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) | |
2512 | { | |
2513 | if (!CP_TYPE_CONST_P (type)) | |
2514 | inform (DECL_SOURCE_LOCATION (r), | |
2515 | "%q#D is not const", r); | |
2516 | else if (CP_TYPE_VOLATILE_P (type)) | |
2517 | inform (DECL_SOURCE_LOCATION (r), | |
2518 | "%q#D is volatile", r); | |
2519 | else if (!DECL_INITIAL (r) | |
2520 | || !TREE_CONSTANT (DECL_INITIAL (r))) | |
2521 | inform (DECL_SOURCE_LOCATION (r), | |
2522 | "%qD was not initialized with a constant " | |
2523 | "expression", r); | |
2524 | else | |
2525 | gcc_unreachable (); | |
2526 | } | |
2527 | else | |
2528 | { | |
2529 | if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r)) | |
2530 | inform (DECL_SOURCE_LOCATION (r), | |
2531 | "%qD was not declared %<constexpr%>", r); | |
2532 | else | |
2533 | inform (DECL_SOURCE_LOCATION (r), | |
2534 | "%qD does not have integral or enumeration type", | |
2535 | r); | |
2536 | } | |
2537 | } | |
2538 | ||
2539 | /* Subroutine of cxx_eval_constant_expression. | |
2540 | Like cxx_eval_unary_expression, except for trinary expressions. */ | |
2541 | ||
2542 | static tree | |
cf72f34d | 2543 | cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2544 | bool lval, |
09b42213 | 2545 | bool *non_constant_p, bool *overflow_p) |
2546 | { | |
2547 | int i; | |
2548 | tree args[3]; | |
2549 | tree val; | |
2550 | ||
2551 | for (i = 0; i < 3; i++) | |
2552 | { | |
cf72f34d | 2553 | args[i] = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, i), |
1227ba74 | 2554 | lval, |
b2a43197 | 2555 | non_constant_p, overflow_p); |
09b42213 | 2556 | VERIFY_CONSTANT (args[i]); |
2557 | } | |
2558 | ||
2559 | val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t), | |
2560 | args[0], args[1], args[2]); | |
2561 | if (val == NULL_TREE) | |
2562 | return t; | |
2563 | VERIFY_CONSTANT (val); | |
2564 | return val; | |
2565 | } | |
2566 | ||
2567 | bool | |
2568 | var_in_constexpr_fn (tree t) | |
2569 | { | |
2570 | tree ctx = DECL_CONTEXT (t); | |
2571 | return (cxx_dialect >= cxx14 && ctx && TREE_CODE (ctx) == FUNCTION_DECL | |
2572 | && DECL_DECLARED_CONSTEXPR_P (ctx)); | |
2573 | } | |
2574 | ||
9c96033c | 2575 | /* Evaluate an INIT_EXPR or MODIFY_EXPR. */ |
2576 | ||
2577 | static tree | |
2578 | cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 2579 | bool lval, |
9c96033c | 2580 | bool *non_constant_p, bool *overflow_p) |
2581 | { | |
2582 | constexpr_ctx new_ctx = *ctx; | |
2583 | ||
8a36d0ec | 2584 | tree init = TREE_OPERAND (t, 1); |
2585 | if (TREE_CLOBBER_P (init)) | |
2586 | /* Just ignore clobbers. */ | |
2587 | return void_node; | |
2588 | ||
9c96033c | 2589 | /* First we figure out where we're storing to. */ |
2590 | tree target = TREE_OPERAND (t, 0); | |
9db9fc38 | 2591 | tree type = TREE_TYPE (target); |
9c96033c | 2592 | target = cxx_eval_constant_expression (ctx, target, |
f83e6885 | 2593 | true, |
b2a43197 | 2594 | non_constant_p, overflow_p); |
9c96033c | 2595 | if (*non_constant_p) |
2596 | return t; | |
2597 | ||
9db9fc38 | 2598 | if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (target), type)) |
2599 | { | |
2600 | /* For initialization of an empty base, the original target will be | |
2601 | *(base*)this, which the above evaluation resolves to the object | |
2602 | argument, which has the derived type rather than the base type. In | |
2603 | this situation, just evaluate the initializer and return, since | |
2604 | there's no actual data to store. */ | |
2605 | gcc_assert (is_empty_class (type)); | |
2606 | return cxx_eval_constant_expression (ctx, init, false, | |
2607 | non_constant_p, overflow_p); | |
2608 | } | |
2609 | ||
9c96033c | 2610 | /* And then find the underlying variable. */ |
2611 | vec<tree,va_gc> *refs = make_tree_vector(); | |
2612 | tree object = NULL_TREE; | |
2613 | for (tree probe = target; object == NULL_TREE; ) | |
2614 | { | |
2615 | switch (TREE_CODE (probe)) | |
2616 | { | |
2617 | case BIT_FIELD_REF: | |
2618 | case COMPONENT_REF: | |
2619 | case ARRAY_REF: | |
2620 | vec_safe_push (refs, TREE_OPERAND (probe, 1)); | |
2621 | vec_safe_push (refs, TREE_TYPE (probe)); | |
2622 | probe = TREE_OPERAND (probe, 0); | |
2623 | break; | |
2624 | ||
2625 | default: | |
2626 | object = probe; | |
9c96033c | 2627 | } |
2628 | } | |
2629 | ||
2630 | /* And then find/build up our initializer for the path to the subobject | |
2631 | we're initializing. */ | |
6fe83e54 | 2632 | tree *valp; |
2633 | if (DECL_P (object)) | |
2634 | valp = ctx->values->get (object); | |
2635 | else | |
2636 | valp = NULL; | |
9c96033c | 2637 | if (!valp) |
2638 | { | |
2639 | /* A constant-expression cannot modify objects from outside the | |
2640 | constant-expression. */ | |
f83e6885 | 2641 | if (!ctx->quiet) |
6fe83e54 | 2642 | error ("modification of %qE is not a constant-expression", object); |
9c96033c | 2643 | *non_constant_p = true; |
2644 | return t; | |
2645 | } | |
9db9fc38 | 2646 | type = TREE_TYPE (object); |
9c96033c | 2647 | while (!refs->is_empty()) |
2648 | { | |
2649 | if (*valp == NULL_TREE) | |
2650 | { | |
2651 | *valp = build_constructor (type, NULL); | |
2652 | CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp) = true; | |
2653 | } | |
2654 | ||
2655 | constructor_elt ce; | |
2656 | type = refs->pop(); | |
2657 | ce.index = refs->pop(); | |
2658 | ce.value = NULL_TREE; | |
2659 | ||
2660 | unsigned HOST_WIDE_INT idx = 0; | |
2661 | constructor_elt *cep = NULL; | |
2662 | for (idx = 0; | |
2663 | vec_safe_iterate (CONSTRUCTOR_ELTS (*valp), idx, &cep); | |
2664 | idx++) | |
2665 | /* ??? slow */ | |
2666 | if (cp_tree_equal (ce.index, cep->index)) | |
2667 | break; | |
2668 | if (!cep) | |
2669 | cep = vec_safe_push (CONSTRUCTOR_ELTS (*valp), ce); | |
2670 | valp = &cep->value; | |
2671 | } | |
2672 | release_tree_vector (refs); | |
2673 | ||
2674 | if ((AGGREGATE_TYPE_P (TREE_TYPE (t)) || VECTOR_TYPE_P (TREE_TYPE (t)))) | |
2675 | { | |
2676 | /* Create a new CONSTRUCTOR in case evaluation of the initializer | |
2677 | wants to modify it. */ | |
2678 | *valp = new_ctx.ctor = build_constructor (TREE_TYPE (t), NULL); | |
2679 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
2680 | new_ctx.object = target; | |
2681 | } | |
2682 | ||
8a36d0ec | 2683 | init = cxx_eval_constant_expression (&new_ctx, init, false, |
2684 | non_constant_p, overflow_p); | |
9c96033c | 2685 | if (target == object) |
2686 | /* The hash table might have moved since the get earlier. */ | |
2687 | ctx->values->put (object, init); | |
2688 | else | |
2689 | *valp = init; | |
2690 | ||
2691 | if (*non_constant_p) | |
2692 | return t; | |
1227ba74 | 2693 | else if (lval) |
9c96033c | 2694 | return target; |
2695 | else | |
dfac7dd2 | 2696 | return init; |
9c96033c | 2697 | } |
2698 | ||
2699 | /* Evaluate a ++ or -- expression. */ | |
2700 | ||
2701 | static tree | |
2702 | cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 2703 | bool lval, |
9c96033c | 2704 | bool *non_constant_p, bool *overflow_p) |
2705 | { | |
2706 | enum tree_code code = TREE_CODE (t); | |
2707 | tree type = TREE_TYPE (t); | |
2708 | tree op = TREE_OPERAND (t, 0); | |
2709 | tree offset = TREE_OPERAND (t, 1); | |
2710 | gcc_assert (TREE_CONSTANT (offset)); | |
2711 | ||
2712 | /* The operand as an lvalue. */ | |
f83e6885 | 2713 | op = cxx_eval_constant_expression (ctx, op, true, |
b2a43197 | 2714 | non_constant_p, overflow_p); |
9c96033c | 2715 | |
2716 | /* The operand as an rvalue. */ | |
2717 | tree val = rvalue (op); | |
f83e6885 | 2718 | val = cxx_eval_constant_expression (ctx, val, false, |
b2a43197 | 2719 | non_constant_p, overflow_p); |
35f2c28f | 2720 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
2721 | a local array in a constexpr function. */ | |
2722 | bool ptr = POINTER_TYPE_P (TREE_TYPE (val)); | |
2723 | if (!ptr) | |
2724 | VERIFY_CONSTANT (val); | |
9c96033c | 2725 | |
2726 | /* The modified value. */ | |
2727 | bool inc = (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR); | |
c8a8f7ad | 2728 | tree mod; |
2729 | if (POINTER_TYPE_P (type)) | |
2730 | { | |
2731 | /* The middle end requires pointers to use POINTER_PLUS_EXPR. */ | |
2732 | offset = convert_to_ptrofftype (offset); | |
2733 | if (!inc) | |
2734 | offset = fold_build1 (NEGATE_EXPR, TREE_TYPE (offset), offset); | |
2735 | mod = fold_build2 (POINTER_PLUS_EXPR, type, val, offset); | |
2736 | } | |
2737 | else | |
2738 | mod = fold_build2 (inc ? PLUS_EXPR : MINUS_EXPR, type, val, offset); | |
35f2c28f | 2739 | if (!ptr) |
2740 | VERIFY_CONSTANT (mod); | |
9c96033c | 2741 | |
2742 | /* Storing the modified value. */ | |
2743 | tree store = build2 (MODIFY_EXPR, type, op, mod); | |
f83e6885 | 2744 | cxx_eval_constant_expression (ctx, store, |
b2a43197 | 2745 | true, non_constant_p, overflow_p); |
9c96033c | 2746 | |
2747 | /* And the value of the expression. */ | |
2748 | if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) | |
2749 | { | |
2750 | /* Prefix ops are lvalues. */ | |
1227ba74 | 2751 | if (lval) |
9c96033c | 2752 | return op; |
2753 | else | |
2754 | /* But we optimize when the caller wants an rvalue. */ | |
2755 | return mod; | |
2756 | } | |
2757 | else | |
2758 | /* Postfix ops are rvalues. */ | |
2759 | return val; | |
2760 | } | |
2761 | ||
00f21715 | 2762 | /* Predicates for the meaning of *jump_target. */ |
2763 | ||
2764 | static bool | |
2765 | returns (tree *jump_target) | |
2766 | { | |
2767 | return *jump_target | |
2768 | && TREE_CODE (*jump_target) == RETURN_EXPR; | |
2769 | } | |
2770 | ||
2771 | static bool | |
2772 | breaks (tree *jump_target) | |
2773 | { | |
2774 | return *jump_target | |
2775 | && TREE_CODE (*jump_target) == LABEL_DECL | |
2776 | && LABEL_DECL_BREAK (*jump_target); | |
2777 | } | |
2778 | ||
2779 | static bool | |
2780 | continues (tree *jump_target) | |
2781 | { | |
2782 | return *jump_target | |
2783 | && TREE_CODE (*jump_target) == LABEL_DECL | |
2784 | && LABEL_DECL_CONTINUE (*jump_target); | |
2785 | } | |
2786 | ||
2787 | static bool | |
2788 | switches (tree *jump_target) | |
2789 | { | |
2790 | return *jump_target | |
2791 | && TREE_CODE (*jump_target) == INTEGER_CST; | |
2792 | } | |
2793 | ||
2794 | /* Subroutine of cxx_eval_statement_list. Determine whether the statement | |
2795 | at I matches *jump_target. If we're looking for a case label and we see | |
2796 | the default label, copy I into DEFAULT_LABEL. */ | |
2797 | ||
2798 | static bool | |
2799 | label_matches (tree *jump_target, tree_stmt_iterator i, | |
2800 | tree_stmt_iterator& default_label) | |
2801 | { | |
2802 | tree stmt = tsi_stmt (i); | |
2803 | switch (TREE_CODE (*jump_target)) | |
2804 | { | |
2805 | case LABEL_DECL: | |
2806 | if (TREE_CODE (stmt) == LABEL_EXPR | |
2807 | && LABEL_EXPR_LABEL (stmt) == *jump_target) | |
2808 | return true; | |
2809 | break; | |
2810 | ||
2811 | case INTEGER_CST: | |
2812 | if (TREE_CODE (stmt) == CASE_LABEL_EXPR) | |
2813 | { | |
2814 | if (!CASE_LOW (stmt)) | |
2815 | default_label = i; | |
2816 | else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt))) | |
2817 | return true; | |
2818 | } | |
2819 | break; | |
2820 | ||
2821 | default: | |
2822 | gcc_unreachable (); | |
2823 | } | |
2824 | return false; | |
2825 | } | |
2826 | ||
2827 | /* Evaluate a STATEMENT_LIST for side-effects. Handles various jump | |
2828 | semantics, for switch, break, continue, and return. */ | |
2829 | ||
2830 | static tree | |
2831 | cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, | |
00f21715 | 2832 | bool *non_constant_p, bool *overflow_p, |
2833 | tree *jump_target) | |
2834 | { | |
2835 | tree_stmt_iterator i; | |
2836 | tree_stmt_iterator default_label = tree_stmt_iterator(); | |
da7981e0 | 2837 | tree local_target; |
2838 | /* In a statement-expression we want to return the last value. */ | |
2839 | tree r = NULL_TREE; | |
2840 | if (!jump_target) | |
2841 | { | |
2842 | local_target = NULL_TREE; | |
2843 | jump_target = &local_target; | |
2844 | } | |
00f21715 | 2845 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) |
2846 | { | |
2847 | reenter: | |
2848 | tree stmt = tsi_stmt (i); | |
2849 | if (*jump_target) | |
2850 | { | |
2851 | if (TREE_CODE (stmt) == STATEMENT_LIST) | |
2852 | /* The label we want might be inside. */; | |
2853 | else if (label_matches (jump_target, i, default_label)) | |
2854 | /* Found it. */ | |
2855 | *jump_target = NULL_TREE; | |
2856 | else | |
2857 | continue; | |
2858 | } | |
da7981e0 | 2859 | r = cxx_eval_constant_expression (ctx, stmt, false, |
2860 | non_constant_p, overflow_p, | |
2861 | jump_target); | |
00f21715 | 2862 | if (*non_constant_p) |
2863 | break; | |
2864 | if (returns (jump_target) || breaks (jump_target)) | |
2865 | break; | |
2866 | } | |
2867 | if (switches (jump_target) && !tsi_end_p (default_label)) | |
2868 | { | |
2869 | i = default_label; | |
2870 | *jump_target = NULL_TREE; | |
2871 | goto reenter; | |
2872 | } | |
da7981e0 | 2873 | return r; |
00f21715 | 2874 | } |
2875 | ||
2876 | /* Evaluate a LOOP_EXPR for side-effects. Handles break and return | |
2877 | semantics; continue semantics are covered by cxx_eval_statement_list. */ | |
2878 | ||
2879 | static tree | |
2880 | cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 2881 | bool *non_constant_p, bool *overflow_p, |
2882 | tree *jump_target) | |
2883 | { | |
2884 | tree body = TREE_OPERAND (t, 0); | |
2885 | while (true) | |
2886 | { | |
f83e6885 | 2887 | cxx_eval_statement_list (ctx, body, |
00f21715 | 2888 | non_constant_p, overflow_p, jump_target); |
b0295f63 | 2889 | if (returns (jump_target) || breaks (jump_target) || *non_constant_p) |
00f21715 | 2890 | break; |
2891 | } | |
2892 | if (breaks (jump_target)) | |
2893 | *jump_target = NULL_TREE; | |
2894 | return NULL_TREE; | |
2895 | } | |
2896 | ||
2897 | /* Evaluate a SWITCH_EXPR for side-effects. Handles switch and break jump | |
2898 | semantics. */ | |
2899 | ||
2900 | static tree | |
2901 | cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 2902 | bool *non_constant_p, bool *overflow_p, |
2903 | tree *jump_target) | |
2904 | { | |
2905 | tree cond = TREE_OPERAND (t, 0); | |
f83e6885 | 2906 | cond = cxx_eval_constant_expression (ctx, cond, false, |
b2a43197 | 2907 | non_constant_p, overflow_p); |
00f21715 | 2908 | VERIFY_CONSTANT (cond); |
2909 | *jump_target = cond; | |
2910 | ||
2911 | tree body = TREE_OPERAND (t, 1); | |
f83e6885 | 2912 | cxx_eval_statement_list (ctx, body, |
00f21715 | 2913 | non_constant_p, overflow_p, jump_target); |
2914 | if (breaks (jump_target) || switches (jump_target)) | |
2915 | *jump_target = NULL_TREE; | |
2916 | return NULL_TREE; | |
2917 | } | |
2918 | ||
35b68da8 | 2919 | /* Subroutine of cxx_eval_constant_expression. |
2920 | Attempt to reduce a POINTER_PLUS_EXPR expression T. */ | |
2921 | ||
2922 | static tree | |
2923 | cxx_eval_pointer_plus_expression (const constexpr_ctx *ctx, tree t, | |
2924 | bool lval, bool *non_constant_p, | |
2925 | bool *overflow_p) | |
2926 | { | |
51a019c5 | 2927 | tree orig_type = TREE_TYPE (t); |
35b68da8 | 2928 | tree op00 = TREE_OPERAND (t, 0); |
2929 | tree op01 = TREE_OPERAND (t, 1); | |
2930 | location_t loc = EXPR_LOCATION (t); | |
2931 | ||
f070a770 | 2932 | op00 = cxx_eval_constant_expression (ctx, op00, lval, |
2933 | non_constant_p, overflow_p); | |
2934 | ||
35b68da8 | 2935 | STRIP_NOPS (op00); |
2936 | if (TREE_CODE (op00) != ADDR_EXPR) | |
2937 | return NULL_TREE; | |
2938 | ||
2939 | op00 = TREE_OPERAND (op00, 0); | |
2940 | ||
2941 | /* &A[i] p+ j => &A[i + j] */ | |
2942 | if (TREE_CODE (op00) == ARRAY_REF | |
2943 | && TREE_CODE (TREE_OPERAND (op00, 1)) == INTEGER_CST | |
51a019c5 | 2944 | && TREE_CODE (op01) == INTEGER_CST |
2945 | && TYPE_SIZE_UNIT (TREE_TYPE (op00)) | |
2946 | && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (op00))) == INTEGER_CST) | |
35b68da8 | 2947 | { |
2948 | tree type = TREE_TYPE (op00); | |
2949 | t = fold_convert_loc (loc, ssizetype, TREE_OPERAND (op00, 1)); | |
2950 | tree nelts = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (op00, 0))); | |
2951 | /* Don't fold an out-of-bound access. */ | |
2952 | if (!tree_int_cst_le (t, nelts)) | |
2953 | return NULL_TREE; | |
51a019c5 | 2954 | op01 = cp_fold_convert (ssizetype, op01); |
2955 | /* Don't fold if op01 can't be divided exactly by TYPE_SIZE_UNIT. | |
2956 | constexpr int A[1]; ... (char *)&A[0] + 1 */ | |
2957 | if (!integer_zerop (fold_build2_loc (loc, TRUNC_MOD_EXPR, sizetype, | |
2958 | op01, TYPE_SIZE_UNIT (type)))) | |
2959 | return NULL_TREE; | |
35b68da8 | 2960 | /* Make sure to treat the second operand of POINTER_PLUS_EXPR |
2961 | as signed. */ | |
51a019c5 | 2962 | op01 = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, op01, |
35b68da8 | 2963 | TYPE_SIZE_UNIT (type)); |
2964 | t = size_binop_loc (loc, PLUS_EXPR, op01, t); | |
2965 | t = build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (op00, 0), | |
2966 | t, NULL_TREE, NULL_TREE); | |
2967 | t = cp_build_addr_expr (t, tf_warning_or_error); | |
51a019c5 | 2968 | t = cp_fold_convert (orig_type, t); |
35b68da8 | 2969 | return cxx_eval_constant_expression (ctx, t, lval, non_constant_p, |
2970 | overflow_p); | |
2971 | } | |
2972 | ||
2973 | return NULL_TREE; | |
2974 | } | |
2975 | ||
09b42213 | 2976 | /* Attempt to reduce the expression T to a constant value. |
2977 | On failure, issue diagnostic and return error_mark_node. */ | |
2978 | /* FIXME unify with c_fully_fold */ | |
9c96033c | 2979 | /* FIXME overflow_p is too global */ |
09b42213 | 2980 | |
2981 | static tree | |
cf72f34d | 2982 | cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2983 | bool lval, |
00f21715 | 2984 | bool *non_constant_p, bool *overflow_p, |
2985 | tree *jump_target) | |
09b42213 | 2986 | { |
cf72f34d | 2987 | constexpr_ctx new_ctx; |
09b42213 | 2988 | tree r = t; |
2989 | ||
2990 | if (t == error_mark_node) | |
2991 | { | |
2992 | *non_constant_p = true; | |
2993 | return t; | |
2994 | } | |
2995 | if (CONSTANT_CLASS_P (t)) | |
2996 | { | |
2997 | if (TREE_CODE (t) == PTRMEM_CST) | |
2998 | t = cplus_expand_constant (t); | |
f83e6885 | 2999 | else if (TREE_OVERFLOW (t) && (!flag_permissive || ctx->quiet)) |
09b42213 | 3000 | *overflow_p = true; |
3001 | return t; | |
3002 | } | |
09b42213 | 3003 | |
3004 | switch (TREE_CODE (t)) | |
3005 | { | |
9c96033c | 3006 | case RESULT_DECL: |
1227ba74 | 3007 | if (lval) |
9c96033c | 3008 | return t; |
3009 | /* We ask for an rvalue for the RESULT_DECL when indirecting | |
92a9c89e | 3010 | through an invisible reference, or in named return value |
3011 | optimization. */ | |
9c96033c | 3012 | return (*ctx->values->get (t)); |
3013 | ||
09b42213 | 3014 | case VAR_DECL: |
8b2b2f24 | 3015 | case CONST_DECL: |
3016 | /* We used to not check lval for CONST_DECL, but darwin.c uses | |
3017 | CONST_DECL for aggregate constants. */ | |
1227ba74 | 3018 | if (lval) |
09b42213 | 3019 | return t; |
2055d27a | 3020 | if (ctx->strict) |
3021 | r = decl_really_constant_value (t); | |
3022 | else | |
3023 | r = decl_constant_value (t); | |
09b42213 | 3024 | if (TREE_CODE (r) == TARGET_EXPR |
3025 | && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR) | |
3026 | r = TARGET_EXPR_INITIAL (r); | |
cf72f34d | 3027 | if (TREE_CODE (r) == VAR_DECL) |
3028 | if (tree *p = ctx->values->get (r)) | |
3029 | r = *p; | |
09b42213 | 3030 | if (DECL_P (r)) |
3031 | { | |
f83e6885 | 3032 | if (!ctx->quiet) |
09b42213 | 3033 | non_const_var_error (r); |
3034 | *non_constant_p = true; | |
3035 | } | |
3036 | break; | |
3037 | ||
3038 | case FUNCTION_DECL: | |
3039 | case TEMPLATE_DECL: | |
3040 | case LABEL_DECL: | |
00f21715 | 3041 | case LABEL_EXPR: |
3042 | case CASE_LABEL_EXPR: | |
09b42213 | 3043 | return t; |
3044 | ||
3045 | case PARM_DECL: | |
88a59139 | 3046 | if (lval && TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE) |
9c96033c | 3047 | /* glvalue use. */; |
3048 | else if (tree *p = ctx->values->get (r)) | |
3049 | r = *p; | |
1227ba74 | 3050 | else if (lval) |
09b42213 | 3051 | /* Defer in case this is only used for its type. */; |
1eb418cc | 3052 | else if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE) |
3053 | /* Defer, there's no lvalue->rvalue conversion. */; | |
a6613de7 | 3054 | else if (is_empty_class (TREE_TYPE (t))) |
3055 | { | |
3056 | /* If the class is empty, we aren't actually loading anything. */ | |
3057 | r = build_constructor (TREE_TYPE (t), NULL); | |
3058 | TREE_CONSTANT (r) = true; | |
3059 | } | |
09b42213 | 3060 | else |
3061 | { | |
f83e6885 | 3062 | if (!ctx->quiet) |
09b42213 | 3063 | error ("%qE is not a constant expression", t); |
3064 | *non_constant_p = true; | |
3065 | } | |
3066 | break; | |
3067 | ||
3068 | case CALL_EXPR: | |
3069 | case AGGR_INIT_EXPR: | |
1227ba74 | 3070 | r = cxx_eval_call_expression (ctx, t, lval, |
09b42213 | 3071 | non_constant_p, overflow_p); |
3072 | break; | |
3073 | ||
9c96033c | 3074 | case DECL_EXPR: |
3075 | { | |
3076 | r = DECL_EXPR_DECL (t); | |
3077 | if (AGGREGATE_TYPE_P (TREE_TYPE (r)) | |
3078 | || VECTOR_TYPE_P (TREE_TYPE (r))) | |
3079 | { | |
3080 | new_ctx = *ctx; | |
3081 | new_ctx.object = r; | |
3082 | new_ctx.ctor = build_constructor (TREE_TYPE (r), NULL); | |
3083 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
3084 | new_ctx.values->put (r, new_ctx.ctor); | |
3085 | ctx = &new_ctx; | |
3086 | } | |
3087 | ||
3088 | if (tree init = DECL_INITIAL (r)) | |
3089 | { | |
3090 | init = cxx_eval_constant_expression (ctx, init, | |
f83e6885 | 3091 | false, |
b2a43197 | 3092 | non_constant_p, overflow_p); |
9c96033c | 3093 | ctx->values->put (r, init); |
3094 | } | |
3095 | else if (ctx == &new_ctx) | |
3096 | /* We gave it a CONSTRUCTOR above. */; | |
3097 | else | |
3098 | ctx->values->put (r, NULL_TREE); | |
3099 | } | |
3100 | break; | |
3101 | ||
09b42213 | 3102 | case TARGET_EXPR: |
3103 | if (!literal_type_p (TREE_TYPE (t))) | |
3104 | { | |
f83e6885 | 3105 | if (!ctx->quiet) |
09b42213 | 3106 | { |
3107 | error ("temporary of non-literal type %qT in a " | |
3108 | "constant expression", TREE_TYPE (t)); | |
3109 | explain_non_literal_class (TREE_TYPE (t)); | |
3110 | } | |
3111 | *non_constant_p = true; | |
3112 | break; | |
3113 | } | |
cf72f34d | 3114 | if ((AGGREGATE_TYPE_P (TREE_TYPE (t)) || VECTOR_TYPE_P (TREE_TYPE (t)))) |
3115 | { | |
3116 | /* We're being expanded without an explicit target, so start | |
3117 | initializing a new object; expansion with an explicit target | |
3118 | strips the TARGET_EXPR before we get here. */ | |
3119 | new_ctx = *ctx; | |
3120 | new_ctx.ctor = build_constructor (TREE_TYPE (t), NULL); | |
3121 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
3122 | new_ctx.object = TARGET_EXPR_SLOT (t); | |
3123 | ctx->values->put (new_ctx.object, new_ctx.ctor); | |
3124 | ctx = &new_ctx; | |
3125 | } | |
1227ba74 | 3126 | /* Pass false for 'lval' because this indicates |
09b42213 | 3127 | initialization of a temporary. */ |
cf72f34d | 3128 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 3129 | false, |
b2a43197 | 3130 | non_constant_p, overflow_p); |
09b42213 | 3131 | if (!*non_constant_p) |
3132 | /* Adjust the type of the result to the type of the temporary. */ | |
3133 | r = adjust_temp_type (TREE_TYPE (t), r); | |
1227ba74 | 3134 | if (lval) |
1eb418cc | 3135 | { |
3136 | tree slot = TARGET_EXPR_SLOT (t); | |
3137 | ctx->values->put (slot, r); | |
3138 | return slot; | |
3139 | } | |
09b42213 | 3140 | break; |
3141 | ||
9c96033c | 3142 | case INIT_EXPR: |
9c96033c | 3143 | case MODIFY_EXPR: |
1227ba74 | 3144 | r = cxx_eval_store_expression (ctx, t, lval, |
9c96033c | 3145 | non_constant_p, overflow_p); |
3146 | break; | |
3147 | ||
09b42213 | 3148 | case SCOPE_REF: |
cf72f34d | 3149 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 3150 | lval, |
b2a43197 | 3151 | non_constant_p, overflow_p); |
09b42213 | 3152 | break; |
3153 | ||
3154 | case RETURN_EXPR: | |
10fb495c | 3155 | if (TREE_OPERAND (t, 0) != NULL_TREE) |
3156 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
3157 | lval, | |
3158 | non_constant_p, overflow_p); | |
00f21715 | 3159 | *jump_target = t; |
3160 | break; | |
3161 | ||
e0e672a0 | 3162 | case SAVE_EXPR: |
3163 | /* Avoid evaluating a SAVE_EXPR more than once. */ | |
3164 | if (tree *p = ctx->values->get (t)) | |
3165 | r = *p; | |
3166 | else | |
3167 | { | |
c8f6aeb1 | 3168 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), false, |
e0e672a0 | 3169 | non_constant_p, overflow_p); |
3170 | ctx->values->put (t, r); | |
3171 | } | |
3172 | break; | |
3173 | ||
09b42213 | 3174 | case NON_LVALUE_EXPR: |
3175 | case TRY_CATCH_EXPR: | |
3176 | case CLEANUP_POINT_EXPR: | |
3177 | case MUST_NOT_THROW_EXPR: | |
9c96033c | 3178 | case EXPR_STMT: |
3179 | case EH_SPEC_BLOCK: | |
cf72f34d | 3180 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 3181 | lval, |
00f21715 | 3182 | non_constant_p, overflow_p, |
3183 | jump_target); | |
09b42213 | 3184 | break; |
3185 | ||
3186 | /* These differ from cxx_eval_unary_expression in that this doesn't | |
3187 | check for a constant operand or result; an address can be | |
3188 | constant without its operand being, and vice versa. */ | |
3189 | case INDIRECT_REF: | |
1227ba74 | 3190 | r = cxx_eval_indirect_ref (ctx, t, lval, |
09b42213 | 3191 | non_constant_p, overflow_p); |
3192 | break; | |
3193 | ||
3194 | case ADDR_EXPR: | |
3195 | { | |
3196 | tree oldop = TREE_OPERAND (t, 0); | |
cf72f34d | 3197 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 3198 | /*lval*/true, |
b2a43197 | 3199 | non_constant_p, overflow_p); |
09b42213 | 3200 | /* Don't VERIFY_CONSTANT here. */ |
3201 | if (*non_constant_p) | |
3202 | return t; | |
1eb418cc | 3203 | gcc_checking_assert (TREE_CODE (op) != CONSTRUCTOR); |
09b42213 | 3204 | /* This function does more aggressive folding than fold itself. */ |
3205 | r = build_fold_addr_expr_with_type (op, TREE_TYPE (t)); | |
3206 | if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop) | |
3207 | return t; | |
3208 | break; | |
3209 | } | |
3210 | ||
3211 | case REALPART_EXPR: | |
3212 | case IMAGPART_EXPR: | |
3213 | case CONJ_EXPR: | |
3214 | case FIX_TRUNC_EXPR: | |
3215 | case FLOAT_EXPR: | |
3216 | case NEGATE_EXPR: | |
3217 | case ABS_EXPR: | |
3218 | case BIT_NOT_EXPR: | |
3219 | case TRUTH_NOT_EXPR: | |
3220 | case FIXED_CONVERT_EXPR: | |
1227ba74 | 3221 | r = cxx_eval_unary_expression (ctx, t, lval, |
09b42213 | 3222 | non_constant_p, overflow_p); |
3223 | break; | |
3224 | ||
3225 | case SIZEOF_EXPR: | |
3226 | if (SIZEOF_EXPR_TYPE_P (t)) | |
3227 | r = cxx_sizeof_or_alignof_type (TREE_TYPE (TREE_OPERAND (t, 0)), | |
3228 | SIZEOF_EXPR, false); | |
3229 | else if (TYPE_P (TREE_OPERAND (t, 0))) | |
3230 | r = cxx_sizeof_or_alignof_type (TREE_OPERAND (t, 0), SIZEOF_EXPR, | |
3231 | false); | |
3232 | else | |
3233 | r = cxx_sizeof_or_alignof_expr (TREE_OPERAND (t, 0), SIZEOF_EXPR, | |
3234 | false); | |
3235 | if (r == error_mark_node) | |
3236 | r = size_one_node; | |
3237 | VERIFY_CONSTANT (r); | |
3238 | break; | |
3239 | ||
3240 | case COMPOUND_EXPR: | |
3241 | { | |
3242 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
3243 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
3244 | introduced by build_call_a. */ | |
3245 | tree op0 = TREE_OPERAND (t, 0); | |
3246 | tree op1 = TREE_OPERAND (t, 1); | |
3247 | STRIP_NOPS (op1); | |
3248 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
3249 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
f83e6885 | 3250 | r = cxx_eval_constant_expression (ctx, op0, |
1227ba74 | 3251 | lval, non_constant_p, overflow_p, |
00f21715 | 3252 | jump_target); |
09b42213 | 3253 | else |
3254 | { | |
3255 | /* Check that the LHS is constant and then discard it. */ | |
f83e6885 | 3256 | cxx_eval_constant_expression (ctx, op0, |
c8f6aeb1 | 3257 | true, non_constant_p, overflow_p, |
00f21715 | 3258 | jump_target); |
09b42213 | 3259 | op1 = TREE_OPERAND (t, 1); |
f83e6885 | 3260 | r = cxx_eval_constant_expression (ctx, op1, |
1227ba74 | 3261 | lval, non_constant_p, overflow_p, |
00f21715 | 3262 | jump_target); |
09b42213 | 3263 | } |
3264 | } | |
3265 | break; | |
3266 | ||
3267 | case POINTER_PLUS_EXPR: | |
35b68da8 | 3268 | r = cxx_eval_pointer_plus_expression (ctx, t, lval, non_constant_p, |
3269 | overflow_p); | |
3270 | if (r) | |
3271 | break; | |
3272 | /* else fall through */ | |
3273 | ||
09b42213 | 3274 | case PLUS_EXPR: |
3275 | case MINUS_EXPR: | |
3276 | case MULT_EXPR: | |
3277 | case TRUNC_DIV_EXPR: | |
3278 | case CEIL_DIV_EXPR: | |
3279 | case FLOOR_DIV_EXPR: | |
3280 | case ROUND_DIV_EXPR: | |
3281 | case TRUNC_MOD_EXPR: | |
3282 | case CEIL_MOD_EXPR: | |
3283 | case ROUND_MOD_EXPR: | |
3284 | case RDIV_EXPR: | |
3285 | case EXACT_DIV_EXPR: | |
3286 | case MIN_EXPR: | |
3287 | case MAX_EXPR: | |
3288 | case LSHIFT_EXPR: | |
3289 | case RSHIFT_EXPR: | |
3290 | case LROTATE_EXPR: | |
3291 | case RROTATE_EXPR: | |
3292 | case BIT_IOR_EXPR: | |
3293 | case BIT_XOR_EXPR: | |
3294 | case BIT_AND_EXPR: | |
3295 | case TRUTH_XOR_EXPR: | |
3296 | case LT_EXPR: | |
3297 | case LE_EXPR: | |
3298 | case GT_EXPR: | |
3299 | case GE_EXPR: | |
3300 | case EQ_EXPR: | |
3301 | case NE_EXPR: | |
3302 | case UNORDERED_EXPR: | |
3303 | case ORDERED_EXPR: | |
3304 | case UNLT_EXPR: | |
3305 | case UNLE_EXPR: | |
3306 | case UNGT_EXPR: | |
3307 | case UNGE_EXPR: | |
3308 | case UNEQ_EXPR: | |
3309 | case LTGT_EXPR: | |
3310 | case RANGE_EXPR: | |
3311 | case COMPLEX_EXPR: | |
1227ba74 | 3312 | r = cxx_eval_binary_expression (ctx, t, lval, |
09b42213 | 3313 | non_constant_p, overflow_p); |
3314 | break; | |
3315 | ||
3316 | /* fold can introduce non-IF versions of these; still treat them as | |
3317 | short-circuiting. */ | |
3318 | case TRUTH_AND_EXPR: | |
3319 | case TRUTH_ANDIF_EXPR: | |
cf72f34d | 3320 | r = cxx_eval_logical_expression (ctx, t, boolean_false_node, |
09b42213 | 3321 | boolean_true_node, |
1227ba74 | 3322 | lval, |
09b42213 | 3323 | non_constant_p, overflow_p); |
3324 | break; | |
3325 | ||
3326 | case TRUTH_OR_EXPR: | |
3327 | case TRUTH_ORIF_EXPR: | |
cf72f34d | 3328 | r = cxx_eval_logical_expression (ctx, t, boolean_true_node, |
09b42213 | 3329 | boolean_false_node, |
1227ba74 | 3330 | lval, |
09b42213 | 3331 | non_constant_p, overflow_p); |
3332 | break; | |
3333 | ||
3334 | case ARRAY_REF: | |
1227ba74 | 3335 | r = cxx_eval_array_reference (ctx, t, lval, |
09b42213 | 3336 | non_constant_p, overflow_p); |
3337 | break; | |
3338 | ||
3339 | case COMPONENT_REF: | |
3340 | if (is_overloaded_fn (t)) | |
3341 | { | |
3342 | /* We can only get here in checking mode via | |
3343 | build_non_dependent_expr, because any expression that | |
3344 | calls or takes the address of the function will have | |
3345 | pulled a FUNCTION_DECL out of the COMPONENT_REF. */ | |
f83e6885 | 3346 | gcc_checking_assert (ctx->quiet || errorcount); |
09b42213 | 3347 | *non_constant_p = true; |
3348 | return t; | |
3349 | } | |
1227ba74 | 3350 | r = cxx_eval_component_reference (ctx, t, lval, |
09b42213 | 3351 | non_constant_p, overflow_p); |
3352 | break; | |
3353 | ||
3354 | case BIT_FIELD_REF: | |
1227ba74 | 3355 | r = cxx_eval_bit_field_ref (ctx, t, lval, |
09b42213 | 3356 | non_constant_p, overflow_p); |
3357 | break; | |
3358 | ||
3359 | case COND_EXPR: | |
3360 | case VEC_COND_EXPR: | |
1227ba74 | 3361 | r = cxx_eval_conditional_expression (ctx, t, lval, |
00f21715 | 3362 | non_constant_p, overflow_p, |
3363 | jump_target); | |
09b42213 | 3364 | break; |
3365 | ||
3366 | case CONSTRUCTOR: | |
1a3631bc | 3367 | if (TREE_CONSTANT (t)) |
3368 | /* Don't re-process a constant CONSTRUCTOR, but do fold it to | |
3369 | VECTOR_CST if applicable. */ | |
3370 | return fold (t); | |
1227ba74 | 3371 | r = cxx_eval_bare_aggregate (ctx, t, lval, |
09b42213 | 3372 | non_constant_p, overflow_p); |
3373 | break; | |
3374 | ||
3375 | case VEC_INIT_EXPR: | |
3376 | /* We can get this in a defaulted constructor for a class with a | |
3377 | non-static data member of array type. Either the initializer will | |
3378 | be NULL, meaning default-initialization, or it will be an lvalue | |
3379 | or xvalue of the same type, meaning direct-initialization from the | |
3380 | corresponding member. */ | |
1227ba74 | 3381 | r = cxx_eval_vec_init (ctx, t, lval, |
09b42213 | 3382 | non_constant_p, overflow_p); |
3383 | break; | |
3384 | ||
3385 | case FMA_EXPR: | |
3386 | case VEC_PERM_EXPR: | |
1227ba74 | 3387 | r = cxx_eval_trinary_expression (ctx, t, lval, |
09b42213 | 3388 | non_constant_p, overflow_p); |
3389 | break; | |
3390 | ||
3391 | case CONVERT_EXPR: | |
3392 | case VIEW_CONVERT_EXPR: | |
3393 | case NOP_EXPR: | |
3394 | { | |
3395 | tree oldop = TREE_OPERAND (t, 0); | |
cf72f34d | 3396 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 3397 | lval, |
b2a43197 | 3398 | non_constant_p, overflow_p); |
09b42213 | 3399 | if (*non_constant_p) |
3400 | return t; | |
3401 | if (POINTER_TYPE_P (TREE_TYPE (t)) | |
3402 | && TREE_CODE (op) == INTEGER_CST | |
3403 | && !integer_zerop (op)) | |
3404 | { | |
f83e6885 | 3405 | if (!ctx->quiet) |
09b42213 | 3406 | error_at (EXPR_LOC_OR_LOC (t, input_location), |
3407 | "reinterpret_cast from integer to pointer"); | |
3408 | *non_constant_p = true; | |
3409 | return t; | |
3410 | } | |
3411 | if (op == oldop) | |
3412 | /* We didn't fold at the top so we could check for ptr-int | |
3413 | conversion. */ | |
3414 | return fold (t); | |
3415 | r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), op); | |
3416 | /* Conversion of an out-of-range value has implementation-defined | |
3417 | behavior; the language considers it different from arithmetic | |
3418 | overflow, which is undefined. */ | |
3419 | if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op)) | |
3420 | TREE_OVERFLOW (r) = false; | |
3421 | } | |
3422 | break; | |
3423 | ||
3424 | case EMPTY_CLASS_EXPR: | |
3425 | /* This is good enough for a function argument that might not get | |
3426 | used, and they can't do anything with it, so just return it. */ | |
3427 | return t; | |
3428 | ||
9c96033c | 3429 | case STATEMENT_LIST: |
00f21715 | 3430 | new_ctx = *ctx; |
3431 | new_ctx.ctor = new_ctx.object = NULL_TREE; | |
f83e6885 | 3432 | return cxx_eval_statement_list (&new_ctx, t, |
00f21715 | 3433 | non_constant_p, overflow_p, jump_target); |
9c96033c | 3434 | |
3435 | case BIND_EXPR: | |
3436 | return cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t), | |
1227ba74 | 3437 | lval, |
00f21715 | 3438 | non_constant_p, overflow_p, |
3439 | jump_target); | |
9c96033c | 3440 | |
09b42213 | 3441 | case PREINCREMENT_EXPR: |
3442 | case POSTINCREMENT_EXPR: | |
3443 | case PREDECREMENT_EXPR: | |
3444 | case POSTDECREMENT_EXPR: | |
f83e6885 | 3445 | return cxx_eval_increment_expression (ctx, t, |
1227ba74 | 3446 | lval, non_constant_p, overflow_p); |
9c96033c | 3447 | |
3448 | case LAMBDA_EXPR: | |
09b42213 | 3449 | case NEW_EXPR: |
3450 | case VEC_NEW_EXPR: | |
3451 | case DELETE_EXPR: | |
3452 | case VEC_DELETE_EXPR: | |
3453 | case THROW_EXPR: | |
09b42213 | 3454 | case MODOP_EXPR: |
3455 | /* GCC internal stuff. */ | |
3456 | case VA_ARG_EXPR: | |
3457 | case OBJ_TYPE_REF: | |
3458 | case WITH_CLEANUP_EXPR: | |
09b42213 | 3459 | case NON_DEPENDENT_EXPR: |
3460 | case BASELINK: | |
09b42213 | 3461 | case OFFSET_REF: |
f83e6885 | 3462 | if (!ctx->quiet) |
09b42213 | 3463 | error_at (EXPR_LOC_OR_LOC (t, input_location), |
3464 | "expression %qE is not a constant-expression", t); | |
3465 | *non_constant_p = true; | |
3466 | break; | |
3467 | ||
cf72f34d | 3468 | case PLACEHOLDER_EXPR: |
fe235c02 | 3469 | if (!ctx || !ctx->ctor || (lval && !ctx->object) |
3470 | || !(same_type_ignoring_top_level_qualifiers_p | |
3471 | (TREE_TYPE (t), TREE_TYPE (ctx->ctor)))) | |
cf72f34d | 3472 | { |
3473 | /* A placeholder without a referent. We can get here when | |
3474 | checking whether NSDMIs are noexcept, or in massage_init_elt; | |
3475 | just say it's non-constant for now. */ | |
f83e6885 | 3476 | gcc_assert (ctx->quiet); |
cf72f34d | 3477 | *non_constant_p = true; |
3478 | break; | |
3479 | } | |
3480 | else | |
3481 | { | |
3482 | /* Use of the value or address of the current object. We could | |
3483 | use ctx->object unconditionally, but using ctx->ctor when we | |
3484 | can is a minor optimization. */ | |
1227ba74 | 3485 | tree ctor = lval ? ctx->object : ctx->ctor; |
cf72f34d | 3486 | return cxx_eval_constant_expression |
1227ba74 | 3487 | (ctx, ctor, lval, |
b2a43197 | 3488 | non_constant_p, overflow_p); |
cf72f34d | 3489 | } |
3490 | break; | |
3491 | ||
9c96033c | 3492 | case GOTO_EXPR: |
00f21715 | 3493 | *jump_target = TREE_OPERAND (t, 0); |
3494 | gcc_assert (breaks (jump_target) || continues (jump_target)); | |
3495 | break; | |
3496 | ||
9c96033c | 3497 | case LOOP_EXPR: |
f83e6885 | 3498 | cxx_eval_loop_expr (ctx, t, |
00f21715 | 3499 | non_constant_p, overflow_p, jump_target); |
3500 | break; | |
3501 | ||
9c96033c | 3502 | case SWITCH_EXPR: |
f83e6885 | 3503 | cxx_eval_switch_expr (ctx, t, |
00f21715 | 3504 | non_constant_p, overflow_p, jump_target); |
9c96033c | 3505 | break; |
3506 | ||
09b42213 | 3507 | default: |
b9a3af23 | 3508 | if (STATEMENT_CODE_P (TREE_CODE (t))) |
3509 | { | |
3510 | /* This function doesn't know how to deal with pre-genericize | |
3511 | statements; this can only happen with statement-expressions, | |
3512 | so for now just fail. */ | |
3513 | if (!ctx->quiet) | |
3514 | error_at (EXPR_LOCATION (t), | |
3515 | "statement is not a constant-expression"); | |
3516 | } | |
3517 | else | |
3518 | internal_error ("unexpected expression %qE of kind %s", t, | |
3519 | get_tree_code_name (TREE_CODE (t))); | |
09b42213 | 3520 | *non_constant_p = true; |
3521 | break; | |
3522 | } | |
3523 | ||
3524 | if (r == error_mark_node) | |
3525 | *non_constant_p = true; | |
3526 | ||
3527 | if (*non_constant_p) | |
3528 | return t; | |
3529 | else | |
3530 | return r; | |
3531 | } | |
3532 | ||
3533 | static tree | |
cf72f34d | 3534 | cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, |
2055d27a | 3535 | bool strict = true, tree object = NULL_TREE) |
09b42213 | 3536 | { |
3537 | bool non_constant_p = false; | |
3538 | bool overflow_p = false; | |
cf72f34d | 3539 | hash_map<tree,tree> map; |
f9885b8a | 3540 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, allow_non_constant, strict }; |
cf72f34d | 3541 | tree type = initialized_type (t); |
cf72f34d | 3542 | tree r = t; |
3543 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) | |
3544 | { | |
3545 | /* In C++14 an NSDMI can participate in aggregate initialization, | |
3546 | and can refer to the address of the object being initialized, so | |
3547 | we need to pass in the relevant VAR_DECL if we want to do the | |
3548 | evaluation in a single pass. The evaluation will dynamically | |
3549 | update ctx.values for the VAR_DECL. We use the same strategy | |
3550 | for C++11 constexpr constructors that refer to the object being | |
3551 | initialized. */ | |
3552 | ctx.ctor = build_constructor (type, NULL); | |
3553 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctx.ctor) = true; | |
9c96033c | 3554 | if (!object) |
3555 | { | |
3556 | if (TREE_CODE (t) == TARGET_EXPR) | |
3557 | object = TARGET_EXPR_SLOT (t); | |
3558 | else if (TREE_CODE (t) == AGGR_INIT_EXPR) | |
3559 | object = AGGR_INIT_EXPR_SLOT (t); | |
3560 | } | |
cf72f34d | 3561 | ctx.object = object; |
3562 | if (object) | |
3563 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
3564 | (type, TREE_TYPE (object))); | |
3565 | if (object && DECL_P (object)) | |
3566 | map.put (object, ctx.ctor); | |
3567 | if (TREE_CODE (r) == TARGET_EXPR) | |
3568 | /* Avoid creating another CONSTRUCTOR when we expand the | |
3569 | TARGET_EXPR. */ | |
3570 | r = TARGET_EXPR_INITIAL (r); | |
3571 | } | |
3572 | ||
f83e6885 | 3573 | r = cxx_eval_constant_expression (&ctx, r, |
b2a43197 | 3574 | false, &non_constant_p, &overflow_p); |
09b42213 | 3575 | |
3576 | verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); | |
3577 | ||
bbcc9042 | 3578 | /* Mutable logic is a bit tricky: we want to allow initialization of |
3579 | constexpr variables with mutable members, but we can't copy those | |
3580 | members to another constexpr variable. */ | |
3581 | if (TREE_CODE (r) == CONSTRUCTOR | |
3582 | && CONSTRUCTOR_MUTABLE_POISON (r)) | |
09b42213 | 3583 | { |
09b42213 | 3584 | if (!allow_non_constant) |
bbcc9042 | 3585 | error ("%qE is not a constant expression because it refers to " |
3586 | "mutable subobjects of %qT", t, type); | |
09b42213 | 3587 | non_constant_p = true; |
3588 | } | |
3589 | ||
3590 | /* Technically we should check this for all subexpressions, but that | |
3591 | runs into problems with our internal representation of pointer | |
3592 | subtraction and the 5.19 rules are still in flux. */ | |
3593 | if (CONVERT_EXPR_CODE_P (TREE_CODE (r)) | |
3594 | && ARITHMETIC_TYPE_P (TREE_TYPE (r)) | |
3595 | && TREE_CODE (TREE_OPERAND (r, 0)) == ADDR_EXPR) | |
3596 | { | |
3597 | if (!allow_non_constant) | |
3598 | error ("conversion from pointer type %qT " | |
3599 | "to arithmetic type %qT in a constant-expression", | |
3600 | TREE_TYPE (TREE_OPERAND (r, 0)), TREE_TYPE (r)); | |
3601 | non_constant_p = true; | |
3602 | } | |
3603 | ||
3604 | if (!non_constant_p && overflow_p) | |
3605 | non_constant_p = true; | |
3606 | ||
3607 | if (non_constant_p && !allow_non_constant) | |
3608 | return error_mark_node; | |
3609 | else if (non_constant_p && TREE_CONSTANT (r)) | |
3610 | { | |
3611 | /* This isn't actually constant, so unset TREE_CONSTANT. */ | |
3612 | if (EXPR_P (r)) | |
3613 | r = copy_node (r); | |
3614 | else if (TREE_CODE (r) == CONSTRUCTOR) | |
3615 | r = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (r), r); | |
3616 | else | |
3617 | r = build_nop (TREE_TYPE (r), r); | |
3618 | TREE_CONSTANT (r) = false; | |
3619 | } | |
3620 | else if (non_constant_p || r == t) | |
3621 | return t; | |
3622 | ||
3623 | if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r))) | |
3624 | { | |
3625 | if (TREE_CODE (t) == TARGET_EXPR | |
3626 | && TARGET_EXPR_INITIAL (t) == r) | |
3627 | return t; | |
3628 | else | |
3629 | { | |
3630 | r = get_target_expr (r); | |
3631 | TREE_CONSTANT (r) = true; | |
3632 | return r; | |
3633 | } | |
3634 | } | |
3635 | else | |
3636 | return r; | |
3637 | } | |
3638 | ||
3639 | /* Returns true if T is a valid subexpression of a constant expression, | |
3640 | even if it isn't itself a constant expression. */ | |
3641 | ||
3642 | bool | |
3643 | is_sub_constant_expr (tree t) | |
3644 | { | |
3645 | bool non_constant_p = false; | |
3646 | bool overflow_p = false; | |
cf72f34d | 3647 | hash_map <tree, tree> map; |
f9885b8a | 3648 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, true, true }; |
f83e6885 | 3649 | cxx_eval_constant_expression (&ctx, t, false, &non_constant_p, |
b2a43197 | 3650 | &overflow_p); |
09b42213 | 3651 | return !non_constant_p && !overflow_p; |
3652 | } | |
3653 | ||
3654 | /* If T represents a constant expression returns its reduced value. | |
3655 | Otherwise return error_mark_node. If T is dependent, then | |
3656 | return NULL. */ | |
3657 | ||
3658 | tree | |
cf72f34d | 3659 | cxx_constant_value (tree t, tree decl) |
09b42213 | 3660 | { |
2055d27a | 3661 | return cxx_eval_outermost_constant_expr (t, false, true, decl); |
09b42213 | 3662 | } |
3663 | ||
3664 | /* If T is a constant expression, returns its reduced value. | |
3665 | Otherwise, if T does not have TREE_CONSTANT set, returns T. | |
3666 | Otherwise, returns a version of T without TREE_CONSTANT. */ | |
3667 | ||
3668 | tree | |
cf72f34d | 3669 | maybe_constant_value (tree t, tree decl) |
09b42213 | 3670 | { |
3671 | tree r; | |
3672 | ||
3673 | if (instantiation_dependent_expression_p (t) | |
3674 | || type_unknown_p (t) | |
3675 | || BRACE_ENCLOSED_INITIALIZER_P (t) | |
3676 | || !potential_constant_expression (t)) | |
3677 | { | |
3678 | if (TREE_OVERFLOW_P (t)) | |
3679 | { | |
3680 | t = build_nop (TREE_TYPE (t), t); | |
3681 | TREE_CONSTANT (t) = false; | |
3682 | } | |
3683 | return t; | |
3684 | } | |
3685 | ||
2055d27a | 3686 | r = cxx_eval_outermost_constant_expr (t, true, true, decl); |
09b42213 | 3687 | #ifdef ENABLE_CHECKING |
09b42213 | 3688 | gcc_assert (r == t |
3689 | || CONVERT_EXPR_P (t) | |
21131a05 | 3690 | || TREE_CODE (t) == VIEW_CONVERT_EXPR |
09b42213 | 3691 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) |
3692 | || !cp_tree_equal (r, t)); | |
3693 | #endif | |
3694 | return r; | |
3695 | } | |
3696 | ||
21131a05 | 3697 | /* Like maybe_constant_value but first fully instantiate the argument. |
3698 | ||
3699 | Note: this is equivalent to instantiate_non_dependent_expr_sfinae | |
3700 | (t, tf_none) followed by maybe_constant_value but is more efficient, | |
3701 | because calls instantiation_dependent_expression_p and | |
3702 | potential_constant_expression at most once. */ | |
3703 | ||
3704 | tree | |
3705 | fold_non_dependent_expr (tree t) | |
3706 | { | |
3707 | if (t == NULL_TREE) | |
3708 | return NULL_TREE; | |
3709 | ||
3710 | /* If we're in a template, but T isn't value dependent, simplify | |
3711 | it. We're supposed to treat: | |
3712 | ||
3713 | template <typename T> void f(T[1 + 1]); | |
3714 | template <typename T> void f(T[2]); | |
3715 | ||
3716 | as two declarations of the same function, for example. */ | |
3717 | if (processing_template_decl) | |
3718 | { | |
3719 | if (!instantiation_dependent_expression_p (t) | |
3720 | && potential_constant_expression (t)) | |
3721 | { | |
c8a9f04c | 3722 | processing_template_decl_sentinel s; |
3723 | t = instantiate_non_dependent_expr_internal (t, tf_none); | |
21131a05 | 3724 | |
3725 | if (type_unknown_p (t) | |
3726 | || BRACE_ENCLOSED_INITIALIZER_P (t)) | |
3727 | { | |
3728 | if (TREE_OVERFLOW_P (t)) | |
3729 | { | |
3730 | t = build_nop (TREE_TYPE (t), t); | |
3731 | TREE_CONSTANT (t) = false; | |
3732 | } | |
3733 | return t; | |
3734 | } | |
3735 | ||
2055d27a | 3736 | tree r = cxx_eval_outermost_constant_expr (t, true, true, NULL_TREE); |
21131a05 | 3737 | #ifdef ENABLE_CHECKING |
3738 | /* cp_tree_equal looks through NOPs, so allow them. */ | |
3739 | gcc_assert (r == t | |
3740 | || CONVERT_EXPR_P (t) | |
3741 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
3742 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
3743 | || !cp_tree_equal (r, t)); | |
3744 | #endif | |
3745 | return r; | |
3746 | } | |
3747 | else if (TREE_OVERFLOW_P (t)) | |
3748 | { | |
3749 | t = build_nop (TREE_TYPE (t), t); | |
3750 | TREE_CONSTANT (t) = false; | |
3751 | } | |
3752 | return t; | |
3753 | } | |
3754 | ||
3755 | return maybe_constant_value (t); | |
3756 | } | |
3757 | ||
09b42213 | 3758 | /* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather |
3759 | than wrapped in a TARGET_EXPR. */ | |
3760 | ||
3761 | tree | |
cf72f34d | 3762 | maybe_constant_init (tree t, tree decl) |
09b42213 | 3763 | { |
3764 | if (TREE_CODE (t) == EXPR_STMT) | |
3765 | t = TREE_OPERAND (t, 0); | |
3766 | if (TREE_CODE (t) == CONVERT_EXPR | |
3767 | && VOID_TYPE_P (TREE_TYPE (t))) | |
3768 | t = TREE_OPERAND (t, 0); | |
9c96033c | 3769 | if (TREE_CODE (t) == INIT_EXPR) |
3770 | t = TREE_OPERAND (t, 1); | |
2055d27a | 3771 | if (instantiation_dependent_expression_p (t) |
3772 | || type_unknown_p (t) | |
3773 | || BRACE_ENCLOSED_INITIALIZER_P (t) | |
3774 | || !potential_static_init_expression (t)) | |
3775 | /* Don't try to evaluate it. */; | |
3776 | else | |
3777 | t = cxx_eval_outermost_constant_expr (t, true, false, decl); | |
09b42213 | 3778 | if (TREE_CODE (t) == TARGET_EXPR) |
3779 | { | |
3780 | tree init = TARGET_EXPR_INITIAL (t); | |
3781 | if (TREE_CODE (init) == CONSTRUCTOR) | |
3782 | t = init; | |
3783 | } | |
3784 | return t; | |
3785 | } | |
3786 | ||
3787 | #if 0 | |
3788 | /* FIXME see ADDR_EXPR section in potential_constant_expression_1. */ | |
3789 | /* Return true if the object referred to by REF has automatic or thread | |
3790 | local storage. */ | |
3791 | ||
3792 | enum { ck_ok, ck_bad, ck_unknown }; | |
3793 | static int | |
3794 | check_automatic_or_tls (tree ref) | |
3795 | { | |
3754d046 | 3796 | machine_mode mode; |
09b42213 | 3797 | HOST_WIDE_INT bitsize, bitpos; |
3798 | tree offset; | |
3799 | int volatilep = 0, unsignedp = 0; | |
3800 | tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset, | |
3801 | &mode, &unsignedp, &volatilep, false); | |
3802 | duration_kind dk; | |
3803 | ||
3804 | /* If there isn't a decl in the middle, we don't know the linkage here, | |
3805 | and this isn't a constant expression anyway. */ | |
3806 | if (!DECL_P (decl)) | |
3807 | return ck_unknown; | |
3808 | dk = decl_storage_duration (decl); | |
3809 | return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok; | |
3810 | } | |
3811 | #endif | |
3812 | ||
3813 | /* Return true if T denotes a potentially constant expression. Issue | |
3814 | diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true, | |
3815 | an lvalue-rvalue conversion is implied. | |
3816 | ||
3817 | C++0x [expr.const] used to say | |
3818 | ||
3819 | 6 An expression is a potential constant expression if it is | |
3820 | a constant expression where all occurrences of function | |
3821 | parameters are replaced by arbitrary constant expressions | |
3822 | of the appropriate type. | |
3823 | ||
3824 | 2 A conditional expression is a constant expression unless it | |
3825 | involves one of the following as a potentially evaluated | |
3826 | subexpression (3.2), but subexpressions of logical AND (5.14), | |
3827 | logical OR (5.15), and conditional (5.16) operations that are | |
3828 | not evaluated are not considered. */ | |
3829 | ||
3830 | static bool | |
2055d27a | 3831 | potential_constant_expression_1 (tree t, bool want_rval, bool strict, |
3832 | tsubst_flags_t flags) | |
09b42213 | 3833 | { |
2055d27a | 3834 | #define RECUR(T,RV) potential_constant_expression_1 ((T), (RV), strict, flags) |
09b42213 | 3835 | enum { any = false, rval = true }; |
3836 | int i; | |
3837 | tree tmp; | |
3838 | ||
3839 | if (t == error_mark_node) | |
3840 | return false; | |
3841 | if (t == NULL_TREE) | |
3842 | return true; | |
3843 | if (TREE_THIS_VOLATILE (t)) | |
3844 | { | |
3845 | if (flags & tf_error) | |
3846 | error ("expression %qE has side-effects", t); | |
3847 | return false; | |
3848 | } | |
3849 | if (CONSTANT_CLASS_P (t)) | |
3850 | return true; | |
3851 | ||
3852 | switch (TREE_CODE (t)) | |
3853 | { | |
3854 | case FUNCTION_DECL: | |
3855 | case BASELINK: | |
3856 | case TEMPLATE_DECL: | |
3857 | case OVERLOAD: | |
3858 | case TEMPLATE_ID_EXPR: | |
3859 | case LABEL_DECL: | |
3860 | case LABEL_EXPR: | |
9c96033c | 3861 | case CASE_LABEL_EXPR: |
09b42213 | 3862 | case CONST_DECL: |
3863 | case SIZEOF_EXPR: | |
3864 | case ALIGNOF_EXPR: | |
3865 | case OFFSETOF_EXPR: | |
3866 | case NOEXCEPT_EXPR: | |
3867 | case TEMPLATE_PARM_INDEX: | |
3868 | case TRAIT_EXPR: | |
3869 | case IDENTIFIER_NODE: | |
3870 | case USERDEF_LITERAL: | |
3871 | /* We can see a FIELD_DECL in a pointer-to-member expression. */ | |
3872 | case FIELD_DECL: | |
3873 | case PARM_DECL: | |
3874 | case USING_DECL: | |
9c96033c | 3875 | case USING_STMT: |
cf72f34d | 3876 | case PLACEHOLDER_EXPR: |
9c96033c | 3877 | case BREAK_STMT: |
3878 | case CONTINUE_STMT: | |
09b42213 | 3879 | return true; |
3880 | ||
3881 | case AGGR_INIT_EXPR: | |
3882 | case CALL_EXPR: | |
3883 | /* -- an invocation of a function other than a constexpr function | |
3884 | or a constexpr constructor. */ | |
3885 | { | |
3886 | tree fun = get_function_named_in_call (t); | |
3887 | const int nargs = call_expr_nargs (t); | |
3888 | i = 0; | |
3889 | ||
9c96033c | 3890 | if (fun == NULL_TREE) |
3891 | { | |
32cf7025 | 3892 | if (TREE_CODE (t) == CALL_EXPR |
3893 | && CALL_EXPR_FN (t) == NULL_TREE) | |
3894 | switch (CALL_EXPR_IFN (t)) | |
3895 | { | |
3896 | /* These should be ignored, they are optimized away from | |
3897 | constexpr functions. */ | |
3898 | case IFN_UBSAN_NULL: | |
3899 | case IFN_UBSAN_BOUNDS: | |
3900 | case IFN_UBSAN_VPTR: | |
3901 | return true; | |
3902 | default: | |
3903 | break; | |
3904 | } | |
9c96033c | 3905 | /* fold_call_expr can't do anything with IFN calls. */ |
3906 | if (flags & tf_error) | |
3907 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
3908 | "call to internal function"); | |
3909 | return false; | |
3910 | } | |
09b42213 | 3911 | if (is_overloaded_fn (fun)) |
3912 | { | |
3913 | if (TREE_CODE (fun) == FUNCTION_DECL) | |
3914 | { | |
3915 | if (builtin_valid_in_constant_expr_p (fun)) | |
3916 | return true; | |
3917 | if (!DECL_DECLARED_CONSTEXPR_P (fun) | |
3918 | /* Allow any built-in function; if the expansion | |
3919 | isn't constant, we'll deal with that then. */ | |
3920 | && !is_builtin_fn (fun)) | |
3921 | { | |
3922 | if (flags & tf_error) | |
3923 | { | |
3924 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
3925 | "call to non-constexpr function %qD", fun); | |
3926 | explain_invalid_constexpr_fn (fun); | |
3927 | } | |
3928 | return false; | |
3929 | } | |
3930 | /* A call to a non-static member function takes the address | |
3931 | of the object as the first argument. But in a constant | |
3932 | expression the address will be folded away, so look | |
3933 | through it now. */ | |
3934 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
3935 | && !DECL_CONSTRUCTOR_P (fun)) | |
3936 | { | |
3937 | tree x = get_nth_callarg (t, 0); | |
3938 | if (is_this_parameter (x)) | |
cf72f34d | 3939 | return true; |
2055d27a | 3940 | else if (!RECUR (x, rval)) |
09b42213 | 3941 | return false; |
3942 | i = 1; | |
3943 | } | |
3944 | } | |
3945 | else | |
3946 | { | |
2055d27a | 3947 | if (!RECUR (fun, true)) |
09b42213 | 3948 | return false; |
3949 | fun = get_first_fn (fun); | |
3950 | } | |
3951 | /* Skip initial arguments to base constructors. */ | |
3952 | if (DECL_BASE_CONSTRUCTOR_P (fun)) | |
3953 | i = num_artificial_parms_for (fun); | |
3954 | fun = DECL_ORIGIN (fun); | |
3955 | } | |
3956 | else | |
3957 | { | |
2055d27a | 3958 | if (RECUR (fun, rval)) |
09b42213 | 3959 | /* Might end up being a constant function pointer. */; |
3960 | else | |
3961 | return false; | |
3962 | } | |
3963 | for (; i < nargs; ++i) | |
3964 | { | |
3965 | tree x = get_nth_callarg (t, i); | |
b2742b58 | 3966 | /* In a template, reference arguments haven't been converted to |
3967 | REFERENCE_TYPE and we might not even know if the parameter | |
3968 | is a reference, so accept lvalue constants too. */ | |
3969 | bool rv = processing_template_decl ? any : rval; | |
3970 | if (!RECUR (x, rv)) | |
09b42213 | 3971 | return false; |
3972 | } | |
3973 | return true; | |
3974 | } | |
3975 | ||
3976 | case NON_LVALUE_EXPR: | |
3977 | /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to | |
3978 | -- an lvalue of integral type that refers to a non-volatile | |
3979 | const variable or static data member initialized with | |
3980 | constant expressions, or | |
3981 | ||
3982 | -- an lvalue of literal type that refers to non-volatile | |
3983 | object defined with constexpr, or that refers to a | |
3984 | sub-object of such an object; */ | |
2055d27a | 3985 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 3986 | |
3987 | case VAR_DECL: | |
2055d27a | 3988 | if (want_rval |
3989 | && !decl_constant_var_p (t) | |
3990 | && (strict | |
3991 | || !CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (t)) | |
3992 | || !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (t)) | |
09b42213 | 3993 | && !var_in_constexpr_fn (t) |
dff5042c | 3994 | && !type_dependent_expression_p (t)) |
09b42213 | 3995 | { |
3996 | if (flags & tf_error) | |
3997 | non_const_var_error (t); | |
3998 | return false; | |
3999 | } | |
4000 | return true; | |
4001 | ||
4002 | case NOP_EXPR: | |
4003 | case CONVERT_EXPR: | |
4004 | case VIEW_CONVERT_EXPR: | |
4005 | /* -- a reinterpret_cast. FIXME not implemented, and this rule | |
4006 | may change to something more specific to type-punning (DR 1312). */ | |
4007 | { | |
4008 | tree from = TREE_OPERAND (t, 0); | |
4009 | if (POINTER_TYPE_P (TREE_TYPE (t)) | |
4010 | && TREE_CODE (from) == INTEGER_CST | |
4011 | && !integer_zerop (from)) | |
4012 | { | |
4013 | if (flags & tf_error) | |
4014 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4015 | "reinterpret_cast from integer to pointer"); | |
4016 | return false; | |
4017 | } | |
2055d27a | 4018 | return (RECUR (from, TREE_CODE (t) != VIEW_CONVERT_EXPR)); |
09b42213 | 4019 | } |
4020 | ||
4021 | case ADDR_EXPR: | |
4022 | /* -- a unary operator & that is applied to an lvalue that | |
4023 | designates an object with thread or automatic storage | |
4024 | duration; */ | |
4025 | t = TREE_OPERAND (t, 0); | |
4026 | ||
4027 | if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t)) | |
4028 | /* A pointer-to-member constant. */ | |
4029 | return true; | |
4030 | ||
4031 | #if 0 | |
4032 | /* FIXME adjust when issue 1197 is fully resolved. For now don't do | |
4033 | any checking here, as we might dereference the pointer later. If | |
4034 | we remove this code, also remove check_automatic_or_tls. */ | |
4035 | i = check_automatic_or_tls (t); | |
4036 | if (i == ck_ok) | |
4037 | return true; | |
4038 | if (i == ck_bad) | |
4039 | { | |
4040 | if (flags & tf_error) | |
4041 | error ("address-of an object %qE with thread local or " | |
4042 | "automatic storage is not a constant expression", t); | |
4043 | return false; | |
4044 | } | |
4045 | #endif | |
2055d27a | 4046 | return RECUR (t, any); |
09b42213 | 4047 | |
4048 | case COMPONENT_REF: | |
4049 | case BIT_FIELD_REF: | |
4050 | case ARROW_EXPR: | |
4051 | case OFFSET_REF: | |
4052 | /* -- a class member access unless its postfix-expression is | |
4053 | of literal type or of pointer to literal type. */ | |
4054 | /* This test would be redundant, as it follows from the | |
4055 | postfix-expression being a potential constant expression. */ | |
2055d27a | 4056 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 4057 | |
4058 | case EXPR_PACK_EXPANSION: | |
2055d27a | 4059 | return RECUR (PACK_EXPANSION_PATTERN (t), want_rval); |
09b42213 | 4060 | |
4061 | case INDIRECT_REF: | |
4062 | { | |
4063 | tree x = TREE_OPERAND (t, 0); | |
4064 | STRIP_NOPS (x); | |
4065 | if (is_this_parameter (x)) | |
4066 | { | |
4067 | if (DECL_CONTEXT (x) | |
4068 | && !DECL_DECLARED_CONSTEXPR_P (DECL_CONTEXT (x))) | |
4069 | { | |
4070 | if (flags & tf_error) | |
4071 | error ("use of %<this%> in a constant expression"); | |
4072 | return false; | |
4073 | } | |
09b42213 | 4074 | return true; |
4075 | } | |
2055d27a | 4076 | return RECUR (x, rval); |
09b42213 | 4077 | } |
4078 | ||
9c96033c | 4079 | case STATEMENT_LIST: |
4080 | { | |
4081 | tree_stmt_iterator i; | |
4082 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
4083 | { | |
2055d27a | 4084 | if (!RECUR (tsi_stmt (i), any)) |
9c96033c | 4085 | return false; |
4086 | } | |
4087 | return true; | |
4088 | } | |
4089 | break; | |
4090 | ||
4091 | case MODIFY_EXPR: | |
4092 | if (cxx_dialect < cxx14) | |
4093 | goto fail; | |
2055d27a | 4094 | if (!RECUR (TREE_OPERAND (t, 0), any)) |
9c96033c | 4095 | return false; |
2055d27a | 4096 | if (!RECUR (TREE_OPERAND (t, 1), rval)) |
9c96033c | 4097 | return false; |
4098 | return true; | |
4099 | ||
4100 | case MODOP_EXPR: | |
4101 | if (cxx_dialect < cxx14) | |
4102 | goto fail; | |
2055d27a | 4103 | if (!RECUR (TREE_OPERAND (t, 0), rval)) |
9c96033c | 4104 | return false; |
2055d27a | 4105 | if (!RECUR (TREE_OPERAND (t, 2), rval)) |
9c96033c | 4106 | return false; |
4107 | return true; | |
4108 | ||
4109 | case IF_STMT: | |
2055d27a | 4110 | if (!RECUR (IF_COND (t), rval)) |
9c96033c | 4111 | return false; |
2055d27a | 4112 | if (!RECUR (THEN_CLAUSE (t), any)) |
9c96033c | 4113 | return false; |
2055d27a | 4114 | if (!RECUR (ELSE_CLAUSE (t), any)) |
9c96033c | 4115 | return false; |
4116 | return true; | |
4117 | ||
4118 | case DO_STMT: | |
2055d27a | 4119 | if (!RECUR (DO_COND (t), rval)) |
9c96033c | 4120 | return false; |
2055d27a | 4121 | if (!RECUR (DO_BODY (t), any)) |
9c96033c | 4122 | return false; |
4123 | return true; | |
4124 | ||
4125 | case FOR_STMT: | |
2055d27a | 4126 | if (!RECUR (FOR_INIT_STMT (t), any)) |
9c96033c | 4127 | return false; |
2055d27a | 4128 | if (!RECUR (FOR_COND (t), rval)) |
9c96033c | 4129 | return false; |
2055d27a | 4130 | if (!RECUR (FOR_EXPR (t), any)) |
9c96033c | 4131 | return false; |
2055d27a | 4132 | if (!RECUR (FOR_BODY (t), any)) |
9c96033c | 4133 | return false; |
4134 | return true; | |
4135 | ||
4136 | case WHILE_STMT: | |
2055d27a | 4137 | if (!RECUR (WHILE_COND (t), rval)) |
9c96033c | 4138 | return false; |
2055d27a | 4139 | if (!RECUR (WHILE_BODY (t), any)) |
9c96033c | 4140 | return false; |
4141 | return true; | |
4142 | ||
4143 | case SWITCH_STMT: | |
2055d27a | 4144 | if (!RECUR (SWITCH_STMT_COND (t), rval)) |
9c96033c | 4145 | return false; |
2055d27a | 4146 | if (!RECUR (SWITCH_STMT_BODY (t), any)) |
9c96033c | 4147 | return false; |
4148 | return true; | |
4149 | ||
da7981e0 | 4150 | case STMT_EXPR: |
2055d27a | 4151 | return RECUR (STMT_EXPR_STMT (t), rval); |
da7981e0 | 4152 | |
09b42213 | 4153 | case LAMBDA_EXPR: |
4154 | case DYNAMIC_CAST_EXPR: | |
4155 | case PSEUDO_DTOR_EXPR: | |
09b42213 | 4156 | case NEW_EXPR: |
4157 | case VEC_NEW_EXPR: | |
4158 | case DELETE_EXPR: | |
4159 | case VEC_DELETE_EXPR: | |
4160 | case THROW_EXPR: | |
09b42213 | 4161 | case OMP_ATOMIC: |
4162 | case OMP_ATOMIC_READ: | |
4163 | case OMP_ATOMIC_CAPTURE_OLD: | |
4164 | case OMP_ATOMIC_CAPTURE_NEW: | |
4165 | /* GCC internal stuff. */ | |
4166 | case VA_ARG_EXPR: | |
4167 | case OBJ_TYPE_REF: | |
09b42213 | 4168 | case TRANSACTION_EXPR: |
9c96033c | 4169 | case ASM_EXPR: |
9abecca2 | 4170 | case AT_ENCODE_EXPR: |
9c96033c | 4171 | fail: |
09b42213 | 4172 | if (flags & tf_error) |
4173 | error ("expression %qE is not a constant-expression", t); | |
4174 | return false; | |
4175 | ||
4176 | case TYPEID_EXPR: | |
4177 | /* -- a typeid expression whose operand is of polymorphic | |
4178 | class type; */ | |
4179 | { | |
4180 | tree e = TREE_OPERAND (t, 0); | |
4181 | if (!TYPE_P (e) && !type_dependent_expression_p (e) | |
4182 | && TYPE_POLYMORPHIC_P (TREE_TYPE (e))) | |
4183 | { | |
4184 | if (flags & tf_error) | |
4185 | error ("typeid-expression is not a constant expression " | |
4186 | "because %qE is of polymorphic type", e); | |
4187 | return false; | |
4188 | } | |
4189 | return true; | |
4190 | } | |
4191 | ||
4192 | case MINUS_EXPR: | |
09b42213 | 4193 | want_rval = true; |
4194 | goto binary; | |
4195 | ||
4196 | case LT_EXPR: | |
4197 | case LE_EXPR: | |
4198 | case GT_EXPR: | |
4199 | case GE_EXPR: | |
4200 | case EQ_EXPR: | |
4201 | case NE_EXPR: | |
09b42213 | 4202 | want_rval = true; |
4203 | goto binary; | |
4204 | ||
9c96033c | 4205 | case PREINCREMENT_EXPR: |
4206 | case POSTINCREMENT_EXPR: | |
4207 | case PREDECREMENT_EXPR: | |
4208 | case POSTDECREMENT_EXPR: | |
4209 | if (cxx_dialect < cxx14) | |
4210 | goto fail; | |
4211 | goto unary; | |
4212 | ||
09b42213 | 4213 | case BIT_NOT_EXPR: |
4214 | /* A destructor. */ | |
4215 | if (TYPE_P (TREE_OPERAND (t, 0))) | |
4216 | return true; | |
4217 | /* else fall through. */ | |
4218 | ||
4219 | case REALPART_EXPR: | |
4220 | case IMAGPART_EXPR: | |
4221 | case CONJ_EXPR: | |
4222 | case SAVE_EXPR: | |
4223 | case FIX_TRUNC_EXPR: | |
4224 | case FLOAT_EXPR: | |
4225 | case NEGATE_EXPR: | |
4226 | case ABS_EXPR: | |
4227 | case TRUTH_NOT_EXPR: | |
4228 | case FIXED_CONVERT_EXPR: | |
4229 | case UNARY_PLUS_EXPR: | |
9c96033c | 4230 | unary: |
2055d27a | 4231 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 4232 | |
4233 | case CAST_EXPR: | |
4234 | case CONST_CAST_EXPR: | |
4235 | case STATIC_CAST_EXPR: | |
4236 | case REINTERPRET_CAST_EXPR: | |
4237 | case IMPLICIT_CONV_EXPR: | |
4238 | if (cxx_dialect < cxx11 | |
4239 | && !dependent_type_p (TREE_TYPE (t)) | |
4240 | && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t))) | |
4241 | /* In C++98, a conversion to non-integral type can't be part of a | |
4242 | constant expression. */ | |
4243 | { | |
4244 | if (flags & tf_error) | |
4245 | error ("cast to non-integral type %qT in a constant expression", | |
4246 | TREE_TYPE (t)); | |
4247 | return false; | |
4248 | } | |
4249 | ||
2055d27a | 4250 | return (RECUR (TREE_OPERAND (t, 0), |
4251 | TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE)); | |
09b42213 | 4252 | |
9c96033c | 4253 | case BIND_EXPR: |
2055d27a | 4254 | return RECUR (BIND_EXPR_BODY (t), want_rval); |
9c96033c | 4255 | |
4256 | case WITH_CLEANUP_EXPR: | |
4257 | case CLEANUP_POINT_EXPR: | |
4258 | case MUST_NOT_THROW_EXPR: | |
4259 | case TRY_CATCH_EXPR: | |
4260 | case EH_SPEC_BLOCK: | |
4261 | case EXPR_STMT: | |
09b42213 | 4262 | case PAREN_EXPR: |
9c96033c | 4263 | case DECL_EXPR: |
09b42213 | 4264 | case NON_DEPENDENT_EXPR: |
4265 | /* For convenience. */ | |
4266 | case RETURN_EXPR: | |
2055d27a | 4267 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 4268 | |
4269 | case SCOPE_REF: | |
2055d27a | 4270 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 4271 | |
4272 | case TARGET_EXPR: | |
4273 | if (!literal_type_p (TREE_TYPE (t))) | |
4274 | { | |
4275 | if (flags & tf_error) | |
4276 | { | |
4277 | error ("temporary of non-literal type %qT in a " | |
4278 | "constant expression", TREE_TYPE (t)); | |
4279 | explain_non_literal_class (TREE_TYPE (t)); | |
4280 | } | |
4281 | return false; | |
4282 | } | |
4283 | case INIT_EXPR: | |
2055d27a | 4284 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 4285 | |
4286 | case CONSTRUCTOR: | |
4287 | { | |
4288 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
4289 | constructor_elt *ce; | |
4290 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2055d27a | 4291 | if (!RECUR (ce->value, want_rval)) |
09b42213 | 4292 | return false; |
4293 | return true; | |
4294 | } | |
4295 | ||
4296 | case TREE_LIST: | |
4297 | { | |
4298 | gcc_assert (TREE_PURPOSE (t) == NULL_TREE | |
4299 | || DECL_P (TREE_PURPOSE (t))); | |
2055d27a | 4300 | if (!RECUR (TREE_VALUE (t), want_rval)) |
09b42213 | 4301 | return false; |
4302 | if (TREE_CHAIN (t) == NULL_TREE) | |
4303 | return true; | |
2055d27a | 4304 | return RECUR (TREE_CHAIN (t), want_rval); |
09b42213 | 4305 | } |
4306 | ||
4307 | case TRUNC_DIV_EXPR: | |
4308 | case CEIL_DIV_EXPR: | |
4309 | case FLOOR_DIV_EXPR: | |
4310 | case ROUND_DIV_EXPR: | |
4311 | case TRUNC_MOD_EXPR: | |
4312 | case CEIL_MOD_EXPR: | |
4313 | case ROUND_MOD_EXPR: | |
4314 | { | |
4315 | tree denom = TREE_OPERAND (t, 1); | |
2055d27a | 4316 | if (!RECUR (denom, rval)) |
09b42213 | 4317 | return false; |
4318 | /* We can't call cxx_eval_outermost_constant_expr on an expression | |
21131a05 | 4319 | that hasn't been through instantiate_non_dependent_expr yet. */ |
09b42213 | 4320 | if (!processing_template_decl) |
4321 | denom = cxx_eval_outermost_constant_expr (denom, true); | |
4322 | if (integer_zerop (denom)) | |
4323 | { | |
4324 | if (flags & tf_error) | |
4325 | error ("division by zero is not a constant-expression"); | |
4326 | return false; | |
4327 | } | |
4328 | else | |
4329 | { | |
4330 | want_rval = true; | |
2055d27a | 4331 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 4332 | } |
4333 | } | |
4334 | ||
4335 | case COMPOUND_EXPR: | |
4336 | { | |
4337 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
4338 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
4339 | introduced by build_call_a. */ | |
4340 | tree op0 = TREE_OPERAND (t, 0); | |
4341 | tree op1 = TREE_OPERAND (t, 1); | |
4342 | STRIP_NOPS (op1); | |
4343 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
4344 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
2055d27a | 4345 | return RECUR (op0, want_rval); |
09b42213 | 4346 | else |
4347 | goto binary; | |
4348 | } | |
4349 | ||
4350 | /* If the first operand is the non-short-circuit constant, look at | |
4351 | the second operand; otherwise we only care about the first one for | |
4352 | potentiality. */ | |
4353 | case TRUTH_AND_EXPR: | |
4354 | case TRUTH_ANDIF_EXPR: | |
4355 | tmp = boolean_true_node; | |
4356 | goto truth; | |
4357 | case TRUTH_OR_EXPR: | |
4358 | case TRUTH_ORIF_EXPR: | |
4359 | tmp = boolean_false_node; | |
4360 | truth: | |
4361 | { | |
4362 | tree op = TREE_OPERAND (t, 0); | |
2055d27a | 4363 | if (!RECUR (op, rval)) |
09b42213 | 4364 | return false; |
4365 | if (!processing_template_decl) | |
4366 | op = cxx_eval_outermost_constant_expr (op, true); | |
4367 | if (tree_int_cst_equal (op, tmp)) | |
2055d27a | 4368 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 4369 | else |
4370 | return true; | |
4371 | } | |
4372 | ||
4373 | case PLUS_EXPR: | |
4374 | case MULT_EXPR: | |
4375 | case POINTER_PLUS_EXPR: | |
4376 | case RDIV_EXPR: | |
4377 | case EXACT_DIV_EXPR: | |
4378 | case MIN_EXPR: | |
4379 | case MAX_EXPR: | |
4380 | case LSHIFT_EXPR: | |
4381 | case RSHIFT_EXPR: | |
4382 | case LROTATE_EXPR: | |
4383 | case RROTATE_EXPR: | |
4384 | case BIT_IOR_EXPR: | |
4385 | case BIT_XOR_EXPR: | |
4386 | case BIT_AND_EXPR: | |
4387 | case TRUTH_XOR_EXPR: | |
4388 | case UNORDERED_EXPR: | |
4389 | case ORDERED_EXPR: | |
4390 | case UNLT_EXPR: | |
4391 | case UNLE_EXPR: | |
4392 | case UNGT_EXPR: | |
4393 | case UNGE_EXPR: | |
4394 | case UNEQ_EXPR: | |
4395 | case LTGT_EXPR: | |
4396 | case RANGE_EXPR: | |
4397 | case COMPLEX_EXPR: | |
4398 | want_rval = true; | |
4399 | /* Fall through. */ | |
4400 | case ARRAY_REF: | |
4401 | case ARRAY_RANGE_REF: | |
4402 | case MEMBER_REF: | |
4403 | case DOTSTAR_EXPR: | |
f0abe78f | 4404 | case MEM_REF: |
09b42213 | 4405 | binary: |
4406 | for (i = 0; i < 2; ++i) | |
2055d27a | 4407 | if (!RECUR (TREE_OPERAND (t, i), want_rval)) |
09b42213 | 4408 | return false; |
4409 | return true; | |
4410 | ||
4411 | case CILK_SYNC_STMT: | |
4412 | case CILK_SPAWN_STMT: | |
4413 | case ARRAY_NOTATION_REF: | |
4414 | return false; | |
4415 | ||
4416 | case FMA_EXPR: | |
4417 | case VEC_PERM_EXPR: | |
4418 | for (i = 0; i < 3; ++i) | |
2055d27a | 4419 | if (!RECUR (TREE_OPERAND (t, i), true)) |
09b42213 | 4420 | return false; |
4421 | return true; | |
4422 | ||
4423 | case COND_EXPR: | |
4424 | case VEC_COND_EXPR: | |
4425 | /* If the condition is a known constant, we know which of the legs we | |
4426 | care about; otherwise we only require that the condition and | |
4427 | either of the legs be potentially constant. */ | |
4428 | tmp = TREE_OPERAND (t, 0); | |
2055d27a | 4429 | if (!RECUR (tmp, rval)) |
09b42213 | 4430 | return false; |
4431 | if (!processing_template_decl) | |
4432 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
4433 | if (integer_zerop (tmp)) | |
2055d27a | 4434 | return RECUR (TREE_OPERAND (t, 2), want_rval); |
09b42213 | 4435 | else if (TREE_CODE (tmp) == INTEGER_CST) |
2055d27a | 4436 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 4437 | for (i = 1; i < 3; ++i) |
4438 | if (potential_constant_expression_1 (TREE_OPERAND (t, i), | |
2055d27a | 4439 | want_rval, strict, tf_none)) |
09b42213 | 4440 | return true; |
4441 | if (flags & tf_error) | |
4442 | error ("expression %qE is not a constant-expression", t); | |
4443 | return false; | |
4444 | ||
4445 | case VEC_INIT_EXPR: | |
4446 | if (VEC_INIT_EXPR_IS_CONSTEXPR (t)) | |
4447 | return true; | |
4448 | if (flags & tf_error) | |
4449 | { | |
4450 | error ("non-constant array initialization"); | |
4451 | diagnose_non_constexpr_vec_init (t); | |
4452 | } | |
4453 | return false; | |
4454 | ||
4455 | default: | |
4456 | if (objc_is_property_ref (t)) | |
4457 | return false; | |
4458 | ||
4459 | sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t))); | |
4460 | gcc_unreachable(); | |
4461 | return false; | |
4462 | } | |
2055d27a | 4463 | #undef RECUR |
09b42213 | 4464 | } |
4465 | ||
4466 | /* The main entry point to the above. */ | |
4467 | ||
4468 | bool | |
4469 | potential_constant_expression (tree t) | |
4470 | { | |
2055d27a | 4471 | return potential_constant_expression_1 (t, false, true, tf_none); |
4472 | } | |
4473 | ||
4474 | bool | |
4475 | potential_static_init_expression (tree t) | |
4476 | { | |
4477 | return potential_constant_expression_1 (t, false, false, tf_none); | |
09b42213 | 4478 | } |
4479 | ||
4480 | /* As above, but require a constant rvalue. */ | |
4481 | ||
4482 | bool | |
4483 | potential_rvalue_constant_expression (tree t) | |
4484 | { | |
2055d27a | 4485 | return potential_constant_expression_1 (t, true, true, tf_none); |
09b42213 | 4486 | } |
4487 | ||
4488 | /* Like above, but complain about non-constant expressions. */ | |
4489 | ||
4490 | bool | |
4491 | require_potential_constant_expression (tree t) | |
4492 | { | |
2055d27a | 4493 | return potential_constant_expression_1 (t, false, true, tf_warning_or_error); |
09b42213 | 4494 | } |
4495 | ||
4496 | /* Cross product of the above. */ | |
4497 | ||
4498 | bool | |
4499 | require_potential_rvalue_constant_expression (tree t) | |
4500 | { | |
2055d27a | 4501 | return potential_constant_expression_1 (t, true, true, tf_warning_or_error); |
09b42213 | 4502 | } |
4503 | ||
4504 | #include "gt-cp-constexpr.h" |