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09b42213 | 1 | /* Perform the semantic phase of constexpr parsing, i.e., the process of |
2 | building tree structure, checking semantic consistency, and | |
3 | building RTL. These routines are used both during actual parsing | |
4 | and during the instantiation of template functions. | |
5 | ||
6 | Copyright (C) 1998-2014 Free Software Foundation, Inc. | |
7 | ||
8 | This file is part of GCC. | |
9 | ||
10 | GCC is free software; you can redistribute it and/or modify it | |
11 | under the terms of the GNU General Public License as published by | |
12 | the Free Software Foundation; either version 3, or (at your option) | |
13 | any later version. | |
14 | ||
15 | GCC is distributed in the hope that it will be useful, but | |
16 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
18 | General Public License for more details. | |
19 | ||
20 | You should have received a copy of the GNU General Public License | |
21 | along with GCC; see the file COPYING3. If not see | |
22 | <http://www.gnu.org/licenses/>. */ | |
23 | ||
24 | #include "config.h" | |
25 | #include "system.h" | |
26 | #include "coretypes.h" | |
27 | #include "tree.h" | |
28 | #include "varasm.h" | |
29 | #include "cp-tree.h" | |
30 | #include "c-family/c-objc.h" | |
31 | #include "tree-iterator.h" | |
32 | #include "gimplify.h" | |
33 | #include "builtins.h" | |
9c96033c | 34 | #include "tree-inline.h" |
09b42213 | 35 | |
36 | static bool verify_constant (tree, bool, bool *, bool *); | |
37 | #define VERIFY_CONSTANT(X) \ | |
38 | do { \ | |
f83e6885 | 39 | if (verify_constant ((X), ctx->quiet, non_constant_p, overflow_p)) \ |
09b42213 | 40 | return t; \ |
41 | } while (0) | |
42 | ||
43 | /* Returns true iff FUN is an instantiation of a constexpr function | |
44 | template or a defaulted constexpr function. */ | |
45 | ||
46 | bool | |
47 | is_instantiation_of_constexpr (tree fun) | |
48 | { | |
49 | return ((DECL_TEMPLOID_INSTANTIATION (fun) | |
50 | && DECL_DECLARED_CONSTEXPR_P (DECL_TI_TEMPLATE (fun))) | |
51 | || (DECL_DEFAULTED_FN (fun) | |
52 | && DECL_DECLARED_CONSTEXPR_P (fun))); | |
53 | } | |
54 | ||
55 | /* Return true if T is a literal type. */ | |
56 | ||
57 | bool | |
58 | literal_type_p (tree t) | |
59 | { | |
60 | if (SCALAR_TYPE_P (t) | |
61 | || TREE_CODE (t) == VECTOR_TYPE | |
62 | || TREE_CODE (t) == REFERENCE_TYPE) | |
63 | return true; | |
64 | if (CLASS_TYPE_P (t)) | |
65 | { | |
66 | t = complete_type (t); | |
67 | gcc_assert (COMPLETE_TYPE_P (t) || errorcount); | |
68 | return CLASSTYPE_LITERAL_P (t); | |
69 | } | |
70 | if (TREE_CODE (t) == ARRAY_TYPE) | |
71 | return literal_type_p (strip_array_types (t)); | |
72 | return false; | |
73 | } | |
74 | ||
75 | /* If DECL is a variable declared `constexpr', require its type | |
76 | be literal. Return the DECL if OK, otherwise NULL. */ | |
77 | ||
78 | tree | |
79 | ensure_literal_type_for_constexpr_object (tree decl) | |
80 | { | |
81 | tree type = TREE_TYPE (decl); | |
82 | if (VAR_P (decl) | |
83 | && (DECL_DECLARED_CONSTEXPR_P (decl) | |
84 | || var_in_constexpr_fn (decl)) | |
85 | && !processing_template_decl) | |
86 | { | |
87 | tree stype = strip_array_types (type); | |
88 | if (CLASS_TYPE_P (stype) && !COMPLETE_TYPE_P (complete_type (stype))) | |
89 | /* Don't complain here, we'll complain about incompleteness | |
90 | when we try to initialize the variable. */; | |
91 | else if (!literal_type_p (type)) | |
92 | { | |
93 | if (DECL_DECLARED_CONSTEXPR_P (decl)) | |
94 | error ("the type %qT of constexpr variable %qD is not literal", | |
95 | type, decl); | |
96 | else | |
9c96033c | 97 | { |
98 | error ("variable %qD of non-literal type %qT in %<constexpr%> " | |
99 | "function", decl, type); | |
100 | cp_function_chain->invalid_constexpr = true; | |
101 | } | |
09b42213 | 102 | explain_non_literal_class (type); |
103 | return NULL; | |
104 | } | |
105 | } | |
106 | return decl; | |
107 | } | |
108 | ||
109 | /* Representation of entries in the constexpr function definition table. */ | |
110 | ||
111 | struct GTY((for_user)) constexpr_fundef { | |
112 | tree decl; | |
113 | tree body; | |
114 | }; | |
115 | ||
116 | struct constexpr_fundef_hasher : ggc_hasher<constexpr_fundef *> | |
117 | { | |
118 | static hashval_t hash (constexpr_fundef *); | |
119 | static bool equal (constexpr_fundef *, constexpr_fundef *); | |
120 | }; | |
121 | ||
122 | /* This table holds all constexpr function definitions seen in | |
123 | the current translation unit. */ | |
124 | ||
125 | static GTY (()) hash_table<constexpr_fundef_hasher> *constexpr_fundef_table; | |
126 | ||
127 | /* Utility function used for managing the constexpr function table. | |
128 | Return true if the entries pointed to by P and Q are for the | |
129 | same constexpr function. */ | |
130 | ||
131 | inline bool | |
132 | constexpr_fundef_hasher::equal (constexpr_fundef *lhs, constexpr_fundef *rhs) | |
133 | { | |
134 | return lhs->decl == rhs->decl; | |
135 | } | |
136 | ||
137 | /* Utility function used for managing the constexpr function table. | |
138 | Return a hash value for the entry pointed to by Q. */ | |
139 | ||
140 | inline hashval_t | |
141 | constexpr_fundef_hasher::hash (constexpr_fundef *fundef) | |
142 | { | |
143 | return DECL_UID (fundef->decl); | |
144 | } | |
145 | ||
146 | /* Return a previously saved definition of function FUN. */ | |
147 | ||
148 | static constexpr_fundef * | |
149 | retrieve_constexpr_fundef (tree fun) | |
150 | { | |
151 | constexpr_fundef fundef = { NULL, NULL }; | |
152 | if (constexpr_fundef_table == NULL) | |
153 | return NULL; | |
154 | ||
155 | fundef.decl = fun; | |
156 | return constexpr_fundef_table->find (&fundef); | |
157 | } | |
158 | ||
159 | /* Check whether the parameter and return types of FUN are valid for a | |
160 | constexpr function, and complain if COMPLAIN. */ | |
161 | ||
162 | static bool | |
163 | is_valid_constexpr_fn (tree fun, bool complain) | |
164 | { | |
165 | bool ret = true; | |
166 | ||
167 | if (DECL_INHERITED_CTOR_BASE (fun) | |
168 | && TREE_CODE (fun) == TEMPLATE_DECL) | |
169 | { | |
170 | ret = false; | |
171 | if (complain) | |
172 | error ("inherited constructor %qD is not constexpr", | |
173 | get_inherited_ctor (fun)); | |
174 | } | |
175 | else | |
176 | { | |
177 | for (tree parm = FUNCTION_FIRST_USER_PARM (fun); | |
178 | parm != NULL_TREE; parm = TREE_CHAIN (parm)) | |
179 | if (!literal_type_p (TREE_TYPE (parm))) | |
180 | { | |
181 | ret = false; | |
182 | if (complain) | |
183 | { | |
184 | error ("invalid type for parameter %d of constexpr " | |
185 | "function %q+#D", DECL_PARM_INDEX (parm), fun); | |
186 | explain_non_literal_class (TREE_TYPE (parm)); | |
187 | } | |
188 | } | |
189 | } | |
190 | ||
191 | if (!DECL_CONSTRUCTOR_P (fun)) | |
192 | { | |
193 | tree rettype = TREE_TYPE (TREE_TYPE (fun)); | |
194 | if (!literal_type_p (rettype)) | |
195 | { | |
196 | ret = false; | |
197 | if (complain) | |
198 | { | |
199 | error ("invalid return type %qT of constexpr function %q+D", | |
200 | rettype, fun); | |
201 | explain_non_literal_class (rettype); | |
202 | } | |
203 | } | |
204 | ||
205 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
206 | && !CLASSTYPE_LITERAL_P (DECL_CONTEXT (fun))) | |
207 | { | |
208 | ret = false; | |
209 | if (complain) | |
210 | { | |
211 | error ("enclosing class of constexpr non-static member " | |
212 | "function %q+#D is not a literal type", fun); | |
213 | explain_non_literal_class (DECL_CONTEXT (fun)); | |
214 | } | |
215 | } | |
216 | } | |
217 | else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun))) | |
218 | { | |
219 | ret = false; | |
220 | if (complain) | |
221 | error ("%q#T has virtual base classes", DECL_CONTEXT (fun)); | |
222 | } | |
223 | ||
224 | return ret; | |
225 | } | |
226 | ||
227 | /* Subroutine of build_data_member_initialization. MEMBER is a COMPONENT_REF | |
228 | for a member of an anonymous aggregate, INIT is the initializer for that | |
229 | member, and VEC_OUTER is the vector of constructor elements for the class | |
230 | whose constructor we are processing. Add the initializer to the vector | |
231 | and return true to indicate success. */ | |
232 | ||
233 | static bool | |
234 | build_anon_member_initialization (tree member, tree init, | |
235 | vec<constructor_elt, va_gc> **vec_outer) | |
236 | { | |
237 | /* MEMBER presents the relevant fields from the inside out, but we need | |
238 | to build up the initializer from the outside in so that we can reuse | |
239 | previously built CONSTRUCTORs if this is, say, the second field in an | |
240 | anonymous struct. So we use a vec as a stack. */ | |
241 | auto_vec<tree, 2> fields; | |
242 | do | |
243 | { | |
244 | fields.safe_push (TREE_OPERAND (member, 1)); | |
245 | member = TREE_OPERAND (member, 0); | |
246 | } | |
247 | while (ANON_AGGR_TYPE_P (TREE_TYPE (member)) | |
248 | && TREE_CODE (member) == COMPONENT_REF); | |
249 | ||
250 | /* VEC has the constructor elements vector for the context of FIELD. | |
251 | If FIELD is an anonymous aggregate, we will push inside it. */ | |
252 | vec<constructor_elt, va_gc> **vec = vec_outer; | |
253 | tree field; | |
254 | while (field = fields.pop(), | |
255 | ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
256 | { | |
257 | tree ctor; | |
258 | /* If there is already an outer constructor entry for the anonymous | |
259 | aggregate FIELD, use it; otherwise, insert one. */ | |
260 | if (vec_safe_is_empty (*vec) | |
261 | || (*vec)->last().index != field) | |
262 | { | |
263 | ctor = build_constructor (TREE_TYPE (field), NULL); | |
264 | CONSTRUCTOR_APPEND_ELT (*vec, field, ctor); | |
265 | } | |
266 | else | |
267 | ctor = (*vec)->last().value; | |
268 | vec = &CONSTRUCTOR_ELTS (ctor); | |
269 | } | |
270 | ||
271 | /* Now we're at the innermost field, the one that isn't an anonymous | |
272 | aggregate. Add its initializer to the CONSTRUCTOR and we're done. */ | |
273 | gcc_assert (fields.is_empty()); | |
274 | CONSTRUCTOR_APPEND_ELT (*vec, field, init); | |
275 | ||
276 | return true; | |
277 | } | |
278 | ||
279 | /* Subroutine of build_constexpr_constructor_member_initializers. | |
280 | The expression tree T represents a data member initialization | |
281 | in a (constexpr) constructor definition. Build a pairing of | |
282 | the data member with its initializer, and prepend that pair | |
283 | to the existing initialization pair INITS. */ | |
284 | ||
285 | static bool | |
286 | build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec) | |
287 | { | |
288 | tree member, init; | |
289 | if (TREE_CODE (t) == CLEANUP_POINT_EXPR) | |
290 | t = TREE_OPERAND (t, 0); | |
291 | if (TREE_CODE (t) == EXPR_STMT) | |
292 | t = TREE_OPERAND (t, 0); | |
293 | if (t == error_mark_node) | |
294 | return false; | |
295 | if (TREE_CODE (t) == STATEMENT_LIST) | |
296 | { | |
297 | tree_stmt_iterator i; | |
298 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
299 | { | |
300 | if (! build_data_member_initialization (tsi_stmt (i), vec)) | |
301 | return false; | |
302 | } | |
303 | return true; | |
304 | } | |
305 | if (TREE_CODE (t) == CLEANUP_STMT) | |
306 | { | |
307 | /* We can't see a CLEANUP_STMT in a constructor for a literal class, | |
308 | but we can in a constexpr constructor for a non-literal class. Just | |
309 | ignore it; either all the initialization will be constant, in which | |
310 | case the cleanup can't run, or it can't be constexpr. | |
311 | Still recurse into CLEANUP_BODY. */ | |
312 | return build_data_member_initialization (CLEANUP_BODY (t), vec); | |
313 | } | |
314 | if (TREE_CODE (t) == CONVERT_EXPR) | |
315 | t = TREE_OPERAND (t, 0); | |
316 | if (TREE_CODE (t) == INIT_EXPR | |
9c96033c | 317 | /* vptr initialization shows up as a MODIFY_EXPR. In C++14 we only |
318 | use what this function builds for cx_check_missing_mem_inits, and | |
319 | assignment in the ctor body doesn't count. */ | |
320 | || (cxx_dialect < cxx14 && TREE_CODE (t) == MODIFY_EXPR)) | |
09b42213 | 321 | { |
322 | member = TREE_OPERAND (t, 0); | |
323 | init = break_out_target_exprs (TREE_OPERAND (t, 1)); | |
324 | } | |
325 | else if (TREE_CODE (t) == CALL_EXPR) | |
326 | { | |
9c96033c | 327 | tree fn = get_callee_fndecl (t); |
328 | if (!fn || !DECL_CONSTRUCTOR_P (fn)) | |
329 | /* We're only interested in calls to subobject constructors. */ | |
330 | return true; | |
09b42213 | 331 | member = CALL_EXPR_ARG (t, 0); |
332 | /* We don't use build_cplus_new here because it complains about | |
333 | abstract bases. Leaving the call unwrapped means that it has the | |
334 | wrong type, but cxx_eval_constant_expression doesn't care. */ | |
335 | init = break_out_target_exprs (t); | |
336 | } | |
337 | else if (TREE_CODE (t) == BIND_EXPR) | |
338 | return build_data_member_initialization (BIND_EXPR_BODY (t), vec); | |
09b42213 | 339 | else |
9c96033c | 340 | /* Don't add anything else to the CONSTRUCTOR. */ |
341 | return true; | |
09b42213 | 342 | if (INDIRECT_REF_P (member)) |
343 | member = TREE_OPERAND (member, 0); | |
344 | if (TREE_CODE (member) == NOP_EXPR) | |
345 | { | |
346 | tree op = member; | |
347 | STRIP_NOPS (op); | |
348 | if (TREE_CODE (op) == ADDR_EXPR) | |
349 | { | |
350 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
351 | (TREE_TYPE (TREE_TYPE (op)), | |
352 | TREE_TYPE (TREE_TYPE (member)))); | |
353 | /* Initializing a cv-qualified member; we need to look through | |
354 | the const_cast. */ | |
355 | member = op; | |
356 | } | |
357 | else if (op == current_class_ptr | |
358 | && (same_type_ignoring_top_level_qualifiers_p | |
359 | (TREE_TYPE (TREE_TYPE (member)), | |
360 | current_class_type))) | |
361 | /* Delegating constructor. */ | |
362 | member = op; | |
363 | else | |
364 | { | |
365 | /* This is an initializer for an empty base; keep it for now so | |
366 | we can check it in cxx_eval_bare_aggregate. */ | |
367 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (member)))); | |
368 | } | |
369 | } | |
370 | if (TREE_CODE (member) == ADDR_EXPR) | |
371 | member = TREE_OPERAND (member, 0); | |
372 | if (TREE_CODE (member) == COMPONENT_REF) | |
373 | { | |
374 | tree aggr = TREE_OPERAND (member, 0); | |
375 | if (TREE_CODE (aggr) != COMPONENT_REF) | |
376 | /* Normal member initialization. */ | |
377 | member = TREE_OPERAND (member, 1); | |
378 | else if (ANON_AGGR_TYPE_P (TREE_TYPE (aggr))) | |
379 | /* Initializing a member of an anonymous union. */ | |
380 | return build_anon_member_initialization (member, init, vec); | |
381 | else | |
382 | /* We're initializing a vtable pointer in a base. Leave it as | |
383 | COMPONENT_REF so we remember the path to get to the vfield. */ | |
384 | gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node); | |
385 | } | |
386 | ||
387 | CONSTRUCTOR_APPEND_ELT (*vec, member, init); | |
388 | return true; | |
389 | } | |
390 | ||
391 | /* Subroutine of check_constexpr_ctor_body_1 and constexpr_fn_retval. | |
392 | In C++11 mode checks that the TYPE_DECLs in the BIND_EXPR_VARS of a | |
393 | BIND_EXPR conform to 7.1.5/3/4 on typedef and alias declarations. */ | |
394 | ||
395 | static bool | |
396 | check_constexpr_bind_expr_vars (tree t) | |
397 | { | |
398 | gcc_assert (TREE_CODE (t) == BIND_EXPR); | |
399 | ||
09b42213 | 400 | for (tree var = BIND_EXPR_VARS (t); var; var = DECL_CHAIN (var)) |
401 | if (TREE_CODE (var) == TYPE_DECL | |
402 | && DECL_IMPLICIT_TYPEDEF_P (var)) | |
403 | return false; | |
404 | return true; | |
405 | } | |
406 | ||
407 | /* Subroutine of check_constexpr_ctor_body. */ | |
408 | ||
409 | static bool | |
410 | check_constexpr_ctor_body_1 (tree last, tree list) | |
411 | { | |
412 | switch (TREE_CODE (list)) | |
413 | { | |
414 | case DECL_EXPR: | |
415 | if (TREE_CODE (DECL_EXPR_DECL (list)) == USING_DECL) | |
416 | return true; | |
09b42213 | 417 | return false; |
418 | ||
419 | case CLEANUP_POINT_EXPR: | |
420 | return check_constexpr_ctor_body (last, TREE_OPERAND (list, 0), | |
421 | /*complain=*/false); | |
422 | ||
423 | case BIND_EXPR: | |
424 | if (!check_constexpr_bind_expr_vars (list) | |
425 | || !check_constexpr_ctor_body (last, BIND_EXPR_BODY (list), | |
426 | /*complain=*/false)) | |
427 | return false; | |
428 | return true; | |
429 | ||
430 | case USING_STMT: | |
431 | case STATIC_ASSERT: | |
432 | return true; | |
433 | ||
434 | default: | |
435 | return false; | |
436 | } | |
437 | } | |
438 | ||
439 | /* Make sure that there are no statements after LAST in the constructor | |
440 | body represented by LIST. */ | |
441 | ||
442 | bool | |
443 | check_constexpr_ctor_body (tree last, tree list, bool complain) | |
444 | { | |
9c96033c | 445 | /* C++14 doesn't require a constexpr ctor to have an empty body. */ |
446 | if (cxx_dialect >= cxx14) | |
447 | return true; | |
448 | ||
09b42213 | 449 | bool ok = true; |
450 | if (TREE_CODE (list) == STATEMENT_LIST) | |
451 | { | |
452 | tree_stmt_iterator i = tsi_last (list); | |
453 | for (; !tsi_end_p (i); tsi_prev (&i)) | |
454 | { | |
455 | tree t = tsi_stmt (i); | |
456 | if (t == last) | |
457 | break; | |
458 | if (!check_constexpr_ctor_body_1 (last, t)) | |
459 | { | |
460 | ok = false; | |
461 | break; | |
462 | } | |
463 | } | |
464 | } | |
465 | else if (list != last | |
466 | && !check_constexpr_ctor_body_1 (last, list)) | |
467 | ok = false; | |
468 | if (!ok) | |
469 | { | |
470 | if (complain) | |
471 | error ("constexpr constructor does not have empty body"); | |
472 | DECL_DECLARED_CONSTEXPR_P (current_function_decl) = false; | |
473 | } | |
474 | return ok; | |
475 | } | |
476 | ||
477 | /* V is a vector of constructor elements built up for the base and member | |
478 | initializers of a constructor for TYPE. They need to be in increasing | |
479 | offset order, which they might not be yet if TYPE has a primary base | |
480 | which is not first in the base-clause or a vptr and at least one base | |
481 | all of which are non-primary. */ | |
482 | ||
483 | static vec<constructor_elt, va_gc> * | |
484 | sort_constexpr_mem_initializers (tree type, vec<constructor_elt, va_gc> *v) | |
485 | { | |
486 | tree pri = CLASSTYPE_PRIMARY_BINFO (type); | |
487 | tree field_type; | |
488 | unsigned i; | |
489 | constructor_elt *ce; | |
490 | ||
491 | if (pri) | |
492 | field_type = BINFO_TYPE (pri); | |
493 | else if (TYPE_CONTAINS_VPTR_P (type)) | |
494 | field_type = vtbl_ptr_type_node; | |
495 | else | |
496 | return v; | |
497 | ||
498 | /* Find the element for the primary base or vptr and move it to the | |
499 | beginning of the vec. */ | |
500 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
501 | if (TREE_TYPE (ce->index) == field_type) | |
502 | break; | |
503 | ||
504 | if (i > 0 && i < vec_safe_length (v)) | |
505 | { | |
506 | vec<constructor_elt, va_gc> &vref = *v; | |
507 | constructor_elt elt = vref[i]; | |
508 | for (; i > 0; --i) | |
509 | vref[i] = vref[i-1]; | |
510 | vref[0] = elt; | |
511 | } | |
512 | ||
513 | return v; | |
514 | } | |
515 | ||
516 | /* Build compile-time evalable representations of member-initializer list | |
517 | for a constexpr constructor. */ | |
518 | ||
519 | static tree | |
520 | build_constexpr_constructor_member_initializers (tree type, tree body) | |
521 | { | |
522 | vec<constructor_elt, va_gc> *vec = NULL; | |
523 | bool ok = true; | |
524 | if (TREE_CODE (body) == MUST_NOT_THROW_EXPR | |
525 | || TREE_CODE (body) == EH_SPEC_BLOCK) | |
526 | body = TREE_OPERAND (body, 0); | |
527 | if (TREE_CODE (body) == STATEMENT_LIST) | |
528 | body = STATEMENT_LIST_HEAD (body)->stmt; | |
529 | body = BIND_EXPR_BODY (body); | |
530 | if (TREE_CODE (body) == CLEANUP_POINT_EXPR) | |
531 | { | |
532 | body = TREE_OPERAND (body, 0); | |
533 | if (TREE_CODE (body) == EXPR_STMT) | |
534 | body = TREE_OPERAND (body, 0); | |
535 | if (TREE_CODE (body) == INIT_EXPR | |
536 | && (same_type_ignoring_top_level_qualifiers_p | |
537 | (TREE_TYPE (TREE_OPERAND (body, 0)), | |
538 | current_class_type))) | |
539 | { | |
540 | /* Trivial copy. */ | |
541 | return TREE_OPERAND (body, 1); | |
542 | } | |
543 | ok = build_data_member_initialization (body, &vec); | |
544 | } | |
545 | else if (TREE_CODE (body) == STATEMENT_LIST) | |
546 | { | |
547 | tree_stmt_iterator i; | |
548 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
549 | { | |
550 | ok = build_data_member_initialization (tsi_stmt (i), &vec); | |
551 | if (!ok) | |
552 | break; | |
553 | } | |
554 | } | |
555 | else if (TREE_CODE (body) == TRY_BLOCK) | |
556 | { | |
557 | error ("body of %<constexpr%> constructor cannot be " | |
558 | "a function-try-block"); | |
559 | return error_mark_node; | |
560 | } | |
561 | else if (EXPR_P (body)) | |
562 | ok = build_data_member_initialization (body, &vec); | |
563 | else | |
564 | gcc_assert (errorcount > 0); | |
565 | if (ok) | |
566 | { | |
567 | if (vec_safe_length (vec) > 0) | |
568 | { | |
569 | /* In a delegating constructor, return the target. */ | |
570 | constructor_elt *ce = &(*vec)[0]; | |
571 | if (ce->index == current_class_ptr) | |
572 | { | |
573 | body = ce->value; | |
574 | vec_free (vec); | |
575 | return body; | |
576 | } | |
577 | } | |
578 | vec = sort_constexpr_mem_initializers (type, vec); | |
579 | return build_constructor (type, vec); | |
580 | } | |
581 | else | |
582 | return error_mark_node; | |
583 | } | |
584 | ||
585 | /* Subroutine of register_constexpr_fundef. BODY is the body of a function | |
586 | declared to be constexpr, or a sub-statement thereof. Returns the | |
587 | return value if suitable, error_mark_node for a statement not allowed in | |
588 | a constexpr function, or NULL_TREE if no return value was found. */ | |
589 | ||
590 | static tree | |
591 | constexpr_fn_retval (tree body) | |
592 | { | |
593 | switch (TREE_CODE (body)) | |
594 | { | |
595 | case STATEMENT_LIST: | |
596 | { | |
597 | tree_stmt_iterator i; | |
598 | tree expr = NULL_TREE; | |
599 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
600 | { | |
601 | tree s = constexpr_fn_retval (tsi_stmt (i)); | |
602 | if (s == error_mark_node) | |
603 | return error_mark_node; | |
604 | else if (s == NULL_TREE) | |
605 | /* Keep iterating. */; | |
606 | else if (expr) | |
607 | /* Multiple return statements. */ | |
608 | return error_mark_node; | |
609 | else | |
610 | expr = s; | |
611 | } | |
612 | return expr; | |
613 | } | |
614 | ||
615 | case RETURN_EXPR: | |
616 | return break_out_target_exprs (TREE_OPERAND (body, 0)); | |
617 | ||
618 | case DECL_EXPR: | |
394aed6a | 619 | { |
620 | tree decl = DECL_EXPR_DECL (body); | |
621 | if (TREE_CODE (decl) == USING_DECL | |
622 | /* Accept __func__, __FUNCTION__, and __PRETTY_FUNCTION__. */ | |
623 | || DECL_ARTIFICIAL (decl)) | |
624 | return NULL_TREE; | |
625 | return error_mark_node; | |
626 | } | |
09b42213 | 627 | |
628 | case CLEANUP_POINT_EXPR: | |
629 | return constexpr_fn_retval (TREE_OPERAND (body, 0)); | |
630 | ||
631 | case BIND_EXPR: | |
632 | if (!check_constexpr_bind_expr_vars (body)) | |
633 | return error_mark_node; | |
634 | return constexpr_fn_retval (BIND_EXPR_BODY (body)); | |
635 | ||
636 | case USING_STMT: | |
637 | return NULL_TREE; | |
638 | ||
639 | default: | |
640 | return error_mark_node; | |
641 | } | |
642 | } | |
643 | ||
644 | /* Subroutine of register_constexpr_fundef. BODY is the DECL_SAVED_TREE of | |
645 | FUN; do the necessary transformations to turn it into a single expression | |
646 | that we can store in the hash table. */ | |
647 | ||
648 | static tree | |
649 | massage_constexpr_body (tree fun, tree body) | |
650 | { | |
651 | if (DECL_CONSTRUCTOR_P (fun)) | |
652 | body = build_constexpr_constructor_member_initializers | |
653 | (DECL_CONTEXT (fun), body); | |
9c96033c | 654 | else if (cxx_dialect < cxx14) |
09b42213 | 655 | { |
656 | if (TREE_CODE (body) == EH_SPEC_BLOCK) | |
657 | body = EH_SPEC_STMTS (body); | |
658 | if (TREE_CODE (body) == MUST_NOT_THROW_EXPR) | |
659 | body = TREE_OPERAND (body, 0); | |
660 | body = constexpr_fn_retval (body); | |
661 | } | |
662 | return body; | |
663 | } | |
664 | ||
665 | /* FUN is a constexpr constructor with massaged body BODY. Return true | |
666 | if some bases/fields are uninitialized, and complain if COMPLAIN. */ | |
667 | ||
668 | static bool | |
669 | cx_check_missing_mem_inits (tree fun, tree body, bool complain) | |
670 | { | |
671 | bool bad; | |
672 | tree field; | |
673 | unsigned i, nelts; | |
674 | tree ctype; | |
675 | ||
676 | if (TREE_CODE (body) != CONSTRUCTOR) | |
677 | return false; | |
678 | ||
679 | nelts = CONSTRUCTOR_NELTS (body); | |
680 | ctype = DECL_CONTEXT (fun); | |
681 | field = TYPE_FIELDS (ctype); | |
682 | ||
683 | if (TREE_CODE (ctype) == UNION_TYPE) | |
684 | { | |
685 | if (nelts == 0 && next_initializable_field (field)) | |
686 | { | |
687 | if (complain) | |
688 | error ("%<constexpr%> constructor for union %qT must " | |
689 | "initialize exactly one non-static data member", ctype); | |
690 | return true; | |
691 | } | |
692 | return false; | |
693 | } | |
694 | ||
695 | bad = false; | |
696 | for (i = 0; i <= nelts; ++i) | |
697 | { | |
698 | tree index; | |
699 | if (i == nelts) | |
700 | index = NULL_TREE; | |
701 | else | |
702 | { | |
703 | index = CONSTRUCTOR_ELT (body, i)->index; | |
704 | /* Skip base and vtable inits. */ | |
705 | if (TREE_CODE (index) != FIELD_DECL | |
706 | || DECL_ARTIFICIAL (index)) | |
707 | continue; | |
708 | } | |
709 | for (; field != index; field = DECL_CHAIN (field)) | |
710 | { | |
711 | tree ftype; | |
712 | if (TREE_CODE (field) != FIELD_DECL | |
713 | || (DECL_C_BIT_FIELD (field) && !DECL_NAME (field)) | |
714 | || DECL_ARTIFICIAL (field)) | |
715 | continue; | |
716 | ftype = strip_array_types (TREE_TYPE (field)); | |
717 | if (type_has_constexpr_default_constructor (ftype)) | |
718 | { | |
719 | /* It's OK to skip a member with a trivial constexpr ctor. | |
720 | A constexpr ctor that isn't trivial should have been | |
721 | added in by now. */ | |
722 | gcc_checking_assert (!TYPE_HAS_COMPLEX_DFLT (ftype) | |
723 | || errorcount != 0); | |
724 | continue; | |
725 | } | |
726 | if (!complain) | |
727 | return true; | |
859e2c29 | 728 | error ("member %qD must be initialized by mem-initializer " |
729 | "in %<constexpr%> constructor", field); | |
730 | inform (DECL_SOURCE_LOCATION (field), "declared here"); | |
09b42213 | 731 | bad = true; |
732 | } | |
733 | if (field == NULL_TREE) | |
734 | break; | |
735 | field = DECL_CHAIN (field); | |
736 | } | |
737 | ||
738 | return bad; | |
739 | } | |
740 | ||
741 | /* We are processing the definition of the constexpr function FUN. | |
742 | Check that its BODY fulfills the propriate requirements and | |
743 | enter it in the constexpr function definition table. | |
744 | For constructor BODY is actually the TREE_LIST of the | |
745 | member-initializer list. */ | |
746 | ||
747 | tree | |
748 | register_constexpr_fundef (tree fun, tree body) | |
749 | { | |
750 | constexpr_fundef entry; | |
751 | constexpr_fundef **slot; | |
752 | ||
753 | if (!is_valid_constexpr_fn (fun, !DECL_GENERATED_P (fun))) | |
754 | return NULL; | |
755 | ||
756 | body = massage_constexpr_body (fun, body); | |
757 | if (body == NULL_TREE || body == error_mark_node) | |
758 | { | |
759 | if (!DECL_CONSTRUCTOR_P (fun)) | |
760 | error ("body of constexpr function %qD not a return-statement", fun); | |
761 | return NULL; | |
762 | } | |
763 | ||
764 | if (!potential_rvalue_constant_expression (body)) | |
765 | { | |
766 | if (!DECL_GENERATED_P (fun)) | |
767 | require_potential_rvalue_constant_expression (body); | |
768 | return NULL; | |
769 | } | |
770 | ||
771 | if (DECL_CONSTRUCTOR_P (fun) | |
772 | && cx_check_missing_mem_inits (fun, body, !DECL_GENERATED_P (fun))) | |
773 | return NULL; | |
774 | ||
775 | /* Create the constexpr function table if necessary. */ | |
776 | if (constexpr_fundef_table == NULL) | |
777 | constexpr_fundef_table | |
778 | = hash_table<constexpr_fundef_hasher>::create_ggc (101); | |
779 | ||
780 | entry.decl = fun; | |
781 | entry.body = body; | |
782 | slot = constexpr_fundef_table->find_slot (&entry, INSERT); | |
783 | ||
784 | gcc_assert (*slot == NULL); | |
785 | *slot = ggc_alloc<constexpr_fundef> (); | |
786 | **slot = entry; | |
787 | ||
788 | return fun; | |
789 | } | |
790 | ||
791 | /* FUN is a non-constexpr function called in a context that requires a | |
792 | constant expression. If it comes from a constexpr template, explain why | |
793 | the instantiation isn't constexpr. */ | |
794 | ||
795 | void | |
796 | explain_invalid_constexpr_fn (tree fun) | |
797 | { | |
798 | static hash_set<tree> *diagnosed; | |
799 | tree body; | |
800 | location_t save_loc; | |
801 | /* Only diagnose defaulted functions or instantiations. */ | |
802 | if (!DECL_DEFAULTED_FN (fun) | |
803 | && !is_instantiation_of_constexpr (fun)) | |
804 | return; | |
805 | if (diagnosed == NULL) | |
806 | diagnosed = new hash_set<tree>; | |
807 | if (diagnosed->add (fun)) | |
808 | /* Already explained. */ | |
809 | return; | |
810 | ||
811 | save_loc = input_location; | |
812 | input_location = DECL_SOURCE_LOCATION (fun); | |
813 | inform (0, "%q+D is not usable as a constexpr function because:", fun); | |
814 | /* First check the declaration. */ | |
815 | if (is_valid_constexpr_fn (fun, true)) | |
816 | { | |
817 | /* Then if it's OK, the body. */ | |
818 | if (!DECL_DECLARED_CONSTEXPR_P (fun)) | |
819 | explain_implicit_non_constexpr (fun); | |
820 | else | |
821 | { | |
822 | body = massage_constexpr_body (fun, DECL_SAVED_TREE (fun)); | |
823 | require_potential_rvalue_constant_expression (body); | |
824 | if (DECL_CONSTRUCTOR_P (fun)) | |
825 | cx_check_missing_mem_inits (fun, body, true); | |
826 | } | |
827 | } | |
828 | input_location = save_loc; | |
829 | } | |
830 | ||
831 | /* Objects of this type represent calls to constexpr functions | |
832 | along with the bindings of parameters to their arguments, for | |
833 | the purpose of compile time evaluation. */ | |
834 | ||
835 | struct GTY((for_user)) constexpr_call { | |
836 | /* Description of the constexpr function definition. */ | |
837 | constexpr_fundef *fundef; | |
838 | /* Parameter bindings environment. A TREE_LIST where each TREE_PURPOSE | |
839 | is a parameter _DECL and the TREE_VALUE is the value of the parameter. | |
840 | Note: This arrangement is made to accommodate the use of | |
841 | iterative_hash_template_arg (see pt.c). If you change this | |
842 | representation, also change the hash calculation in | |
843 | cxx_eval_call_expression. */ | |
844 | tree bindings; | |
845 | /* Result of the call. | |
846 | NULL means the call is being evaluated. | |
847 | error_mark_node means that the evaluation was erroneous; | |
848 | otherwise, the actuall value of the call. */ | |
849 | tree result; | |
850 | /* The hash of this call; we remember it here to avoid having to | |
851 | recalculate it when expanding the hash table. */ | |
852 | hashval_t hash; | |
853 | }; | |
854 | ||
855 | struct constexpr_call_hasher : ggc_hasher<constexpr_call *> | |
856 | { | |
857 | static hashval_t hash (constexpr_call *); | |
858 | static bool equal (constexpr_call *, constexpr_call *); | |
cf72f34d | 859 | }; |
860 | ||
861 | /* The constexpr expansion context. CALL is the current function | |
862 | expansion, CTOR is the current aggregate initializer, OBJECT is the | |
863 | object being initialized by CTOR, either a VAR_DECL or a _REF. VALUES | |
864 | is a map of values of variables initialized within the expression. */ | |
865 | ||
866 | struct constexpr_ctx { | |
867 | constexpr_call *call; | |
868 | hash_map<tree,tree> *values; | |
869 | tree ctor; | |
870 | tree object; | |
f83e6885 | 871 | bool quiet; |
2055d27a | 872 | bool strict; |
cf72f34d | 873 | }; |
09b42213 | 874 | |
875 | /* A table of all constexpr calls that have been evaluated by the | |
876 | compiler in this translation unit. */ | |
877 | ||
878 | static GTY (()) hash_table<constexpr_call_hasher> *constexpr_call_table; | |
879 | ||
cf72f34d | 880 | static tree cxx_eval_constant_expression (const constexpr_ctx *, tree, |
b2a43197 | 881 | bool, bool *, bool *, tree * = NULL); |
09b42213 | 882 | |
883 | /* Compute a hash value for a constexpr call representation. */ | |
884 | ||
885 | inline hashval_t | |
886 | constexpr_call_hasher::hash (constexpr_call *info) | |
887 | { | |
888 | return info->hash; | |
889 | } | |
890 | ||
891 | /* Return true if the objects pointed to by P and Q represent calls | |
892 | to the same constexpr function with the same arguments. | |
893 | Otherwise, return false. */ | |
894 | ||
895 | bool | |
896 | constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs) | |
897 | { | |
898 | tree lhs_bindings; | |
899 | tree rhs_bindings; | |
900 | if (lhs == rhs) | |
901 | return 1; | |
902 | if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef)) | |
903 | return 0; | |
904 | lhs_bindings = lhs->bindings; | |
905 | rhs_bindings = rhs->bindings; | |
906 | while (lhs_bindings != NULL && rhs_bindings != NULL) | |
907 | { | |
908 | tree lhs_arg = TREE_VALUE (lhs_bindings); | |
909 | tree rhs_arg = TREE_VALUE (rhs_bindings); | |
910 | gcc_assert (TREE_TYPE (lhs_arg) == TREE_TYPE (rhs_arg)); | |
911 | if (!cp_tree_equal (lhs_arg, rhs_arg)) | |
912 | return 0; | |
913 | lhs_bindings = TREE_CHAIN (lhs_bindings); | |
914 | rhs_bindings = TREE_CHAIN (rhs_bindings); | |
915 | } | |
916 | return lhs_bindings == rhs_bindings; | |
917 | } | |
918 | ||
919 | /* Initialize the constexpr call table, if needed. */ | |
920 | ||
921 | static void | |
922 | maybe_initialize_constexpr_call_table (void) | |
923 | { | |
924 | if (constexpr_call_table == NULL) | |
925 | constexpr_call_table = hash_table<constexpr_call_hasher>::create_ggc (101); | |
926 | } | |
927 | ||
928 | /* We have an expression tree T that represents a call, either CALL_EXPR | |
929 | or AGGR_INIT_EXPR. If the call is lexically to a named function, | |
930 | retrun the _DECL for that function. */ | |
931 | ||
932 | static tree | |
933 | get_function_named_in_call (tree t) | |
934 | { | |
935 | tree fun = NULL; | |
936 | switch (TREE_CODE (t)) | |
937 | { | |
938 | case CALL_EXPR: | |
939 | fun = CALL_EXPR_FN (t); | |
940 | break; | |
941 | ||
942 | case AGGR_INIT_EXPR: | |
943 | fun = AGGR_INIT_EXPR_FN (t); | |
944 | break; | |
945 | ||
946 | default: | |
947 | gcc_unreachable(); | |
948 | break; | |
949 | } | |
9c96033c | 950 | if (fun && TREE_CODE (fun) == ADDR_EXPR |
09b42213 | 951 | && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL) |
952 | fun = TREE_OPERAND (fun, 0); | |
953 | return fun; | |
954 | } | |
955 | ||
956 | /* We have an expression tree T that represents a call, either CALL_EXPR | |
957 | or AGGR_INIT_EXPR. Return the Nth argument. */ | |
958 | ||
959 | static inline tree | |
960 | get_nth_callarg (tree t, int n) | |
961 | { | |
962 | switch (TREE_CODE (t)) | |
963 | { | |
964 | case CALL_EXPR: | |
965 | return CALL_EXPR_ARG (t, n); | |
966 | ||
967 | case AGGR_INIT_EXPR: | |
968 | return AGGR_INIT_EXPR_ARG (t, n); | |
969 | ||
970 | default: | |
971 | gcc_unreachable (); | |
972 | return NULL; | |
973 | } | |
974 | } | |
975 | ||
976 | /* Look up the binding of the function parameter T in a constexpr | |
977 | function call context CALL. */ | |
978 | ||
979 | static tree | |
980 | lookup_parameter_binding (const constexpr_call *call, tree t) | |
981 | { | |
982 | tree b = purpose_member (t, call->bindings); | |
983 | return TREE_VALUE (b); | |
984 | } | |
985 | ||
986 | /* Attempt to evaluate T which represents a call to a builtin function. | |
987 | We assume here that all builtin functions evaluate to scalar types | |
988 | represented by _CST nodes. */ | |
989 | ||
990 | static tree | |
cf72f34d | 991 | cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, |
f83e6885 | 992 | bool addr, |
09b42213 | 993 | bool *non_constant_p, bool *overflow_p) |
994 | { | |
995 | const int nargs = call_expr_nargs (t); | |
996 | tree *args = (tree *) alloca (nargs * sizeof (tree)); | |
997 | tree new_call; | |
998 | int i; | |
999 | for (i = 0; i < nargs; ++i) | |
1000 | { | |
cf72f34d | 1001 | args[i] = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, i), |
f83e6885 | 1002 | addr, |
b2a43197 | 1003 | non_constant_p, overflow_p); |
f83e6885 | 1004 | if (ctx->quiet && *non_constant_p) |
09b42213 | 1005 | return t; |
1006 | } | |
1007 | if (*non_constant_p) | |
1008 | return t; | |
3ddbf961 | 1009 | new_call = fold_builtin_call_array (EXPR_LOCATION (t), TREE_TYPE (t), |
1010 | CALL_EXPR_FN (t), nargs, args); | |
09b42213 | 1011 | VERIFY_CONSTANT (new_call); |
1012 | return new_call; | |
1013 | } | |
1014 | ||
1015 | /* TEMP is the constant value of a temporary object of type TYPE. Adjust | |
1016 | the type of the value to match. */ | |
1017 | ||
1018 | static tree | |
1019 | adjust_temp_type (tree type, tree temp) | |
1020 | { | |
1021 | if (TREE_TYPE (temp) == type) | |
1022 | return temp; | |
1023 | /* Avoid wrapping an aggregate value in a NOP_EXPR. */ | |
1024 | if (TREE_CODE (temp) == CONSTRUCTOR) | |
1025 | return build_constructor (type, CONSTRUCTOR_ELTS (temp)); | |
1026 | gcc_assert (scalarish_type_p (type)); | |
1027 | return cp_fold_convert (type, temp); | |
1028 | } | |
1029 | ||
9c96033c | 1030 | /* True if we want to use the new handling of constexpr calls based on |
7467eea5 | 1031 | DECL_SAVED_TREE. */ |
1032 | #define use_new_call true | |
9c96033c | 1033 | |
09b42213 | 1034 | /* Subroutine of cxx_eval_call_expression. |
1035 | We are processing a call expression (either CALL_EXPR or | |
cf72f34d | 1036 | AGGR_INIT_EXPR) in the context of CTX. Evaluate |
09b42213 | 1037 | all arguments and bind their values to correspondings |
1038 | parameters, making up the NEW_CALL context. */ | |
1039 | ||
1040 | static void | |
cf72f34d | 1041 | cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, |
09b42213 | 1042 | constexpr_call *new_call, |
09b42213 | 1043 | bool *non_constant_p, bool *overflow_p) |
1044 | { | |
1045 | const int nargs = call_expr_nargs (t); | |
1046 | tree fun = new_call->fundef->decl; | |
1047 | tree parms = DECL_ARGUMENTS (fun); | |
1048 | int i; | |
9c96033c | 1049 | tree *p = &new_call->bindings; |
09b42213 | 1050 | for (i = 0; i < nargs; ++i) |
1051 | { | |
1052 | tree x, arg; | |
1053 | tree type = parms ? TREE_TYPE (parms) : void_type_node; | |
09b42213 | 1054 | x = get_nth_callarg (t, i); |
cf72f34d | 1055 | /* For member function, the first argument is a pointer to the implied |
1056 | object. For a constructor, it might still be a dummy object, in | |
9c96033c | 1057 | which case we get the real argument from ctx. */ |
cf72f34d | 1058 | if (i == 0 && DECL_CONSTRUCTOR_P (fun) |
1059 | && is_dummy_object (x)) | |
1060 | { | |
1061 | x = ctx->object; | |
cf72f34d | 1062 | x = cp_build_addr_expr (x, tf_warning_or_error); |
1063 | } | |
1eb418cc | 1064 | bool addr = false; |
9c96033c | 1065 | if (parms && DECL_BY_REFERENCE (parms) && !use_new_call) |
09b42213 | 1066 | { |
1067 | /* cp_genericize made this a reference for argument passing, but | |
9c96033c | 1068 | we don't want to treat it like one for C++11 constexpr |
1069 | evaluation. C++14 constexpr evaluation uses the genericized | |
1070 | DECL_SAVED_TREE. */ | |
09b42213 | 1071 | gcc_assert (TREE_CODE (type) == REFERENCE_TYPE); |
1072 | gcc_assert (TREE_CODE (TREE_TYPE (x)) == REFERENCE_TYPE); | |
1073 | type = TREE_TYPE (type); | |
1074 | x = convert_from_reference (x); | |
1eb418cc | 1075 | addr = true; |
09b42213 | 1076 | } |
1eb418cc | 1077 | arg = cxx_eval_constant_expression (ctx, x, addr, |
b2a43197 | 1078 | non_constant_p, overflow_p); |
09b42213 | 1079 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 1080 | if (*non_constant_p && ctx->quiet) |
09b42213 | 1081 | return; |
1082 | /* Just discard ellipsis args after checking their constantitude. */ | |
1083 | if (!parms) | |
1084 | continue; | |
1085 | if (*non_constant_p) | |
1086 | /* Don't try to adjust the type of non-constant args. */ | |
1087 | goto next; | |
1088 | ||
1089 | /* Make sure the binding has the same type as the parm. */ | |
1090 | if (TREE_CODE (type) != REFERENCE_TYPE) | |
1091 | arg = adjust_temp_type (type, arg); | |
9c96033c | 1092 | *p = build_tree_list (parms, arg); |
1093 | p = &TREE_CHAIN (*p); | |
09b42213 | 1094 | next: |
1095 | parms = TREE_CHAIN (parms); | |
1096 | } | |
1097 | } | |
1098 | ||
1099 | /* Variables and functions to manage constexpr call expansion context. | |
1100 | These do not need to be marked for PCH or GC. */ | |
1101 | ||
1102 | /* FIXME remember and print actual constant arguments. */ | |
1103 | static vec<tree> call_stack = vNULL; | |
1104 | static int call_stack_tick; | |
1105 | static int last_cx_error_tick; | |
1106 | ||
1107 | static bool | |
1108 | push_cx_call_context (tree call) | |
1109 | { | |
1110 | ++call_stack_tick; | |
1111 | if (!EXPR_HAS_LOCATION (call)) | |
1112 | SET_EXPR_LOCATION (call, input_location); | |
1113 | call_stack.safe_push (call); | |
1114 | if (call_stack.length () > (unsigned) max_constexpr_depth) | |
1115 | return false; | |
1116 | return true; | |
1117 | } | |
1118 | ||
1119 | static void | |
1120 | pop_cx_call_context (void) | |
1121 | { | |
1122 | ++call_stack_tick; | |
1123 | call_stack.pop (); | |
1124 | } | |
1125 | ||
1126 | vec<tree> | |
1127 | cx_error_context (void) | |
1128 | { | |
1129 | vec<tree> r = vNULL; | |
1130 | if (call_stack_tick != last_cx_error_tick | |
1131 | && !call_stack.is_empty ()) | |
1132 | r = call_stack; | |
1133 | last_cx_error_tick = call_stack_tick; | |
1134 | return r; | |
1135 | } | |
1136 | ||
1137 | /* Subroutine of cxx_eval_constant_expression. | |
1138 | Evaluate the call expression tree T in the context of OLD_CALL expression | |
1139 | evaluation. */ | |
1140 | ||
1141 | static tree | |
cf72f34d | 1142 | cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, |
f83e6885 | 1143 | bool addr, |
09b42213 | 1144 | bool *non_constant_p, bool *overflow_p) |
1145 | { | |
1146 | location_t loc = EXPR_LOC_OR_LOC (t, input_location); | |
1147 | tree fun = get_function_named_in_call (t); | |
1148 | tree result; | |
1149 | constexpr_call new_call = { NULL, NULL, NULL, 0 }; | |
1150 | constexpr_call **slot; | |
1151 | constexpr_call *entry; | |
1152 | bool depth_ok; | |
1153 | ||
1154 | if (TREE_CODE (fun) != FUNCTION_DECL) | |
1155 | { | |
1156 | /* Might be a constexpr function pointer. */ | |
f83e6885 | 1157 | fun = cxx_eval_constant_expression (ctx, fun, |
09b42213 | 1158 | /*addr*/false, non_constant_p, |
b2a43197 | 1159 | overflow_p); |
09b42213 | 1160 | STRIP_NOPS (fun); |
1161 | if (TREE_CODE (fun) == ADDR_EXPR) | |
1162 | fun = TREE_OPERAND (fun, 0); | |
1163 | } | |
1164 | if (TREE_CODE (fun) != FUNCTION_DECL) | |
1165 | { | |
f83e6885 | 1166 | if (!ctx->quiet && !*non_constant_p) |
09b42213 | 1167 | error_at (loc, "expression %qE does not designate a constexpr " |
1168 | "function", fun); | |
1169 | *non_constant_p = true; | |
1170 | return t; | |
1171 | } | |
1172 | if (DECL_CLONED_FUNCTION_P (fun)) | |
1173 | fun = DECL_CLONED_FUNCTION (fun); | |
1174 | if (is_builtin_fn (fun)) | |
f83e6885 | 1175 | return cxx_eval_builtin_function_call (ctx, t, |
09b42213 | 1176 | addr, non_constant_p, overflow_p); |
1177 | if (!DECL_DECLARED_CONSTEXPR_P (fun)) | |
1178 | { | |
f83e6885 | 1179 | if (!ctx->quiet) |
09b42213 | 1180 | { |
1181 | error_at (loc, "call to non-constexpr function %qD", fun); | |
1182 | explain_invalid_constexpr_fn (fun); | |
1183 | } | |
1184 | *non_constant_p = true; | |
1185 | return t; | |
1186 | } | |
1187 | ||
1188 | /* Shortcut trivial constructor/op=. */ | |
1189 | if (trivial_fn_p (fun)) | |
1190 | { | |
1191 | if (call_expr_nargs (t) == 2) | |
1192 | { | |
1193 | tree arg = convert_from_reference (get_nth_callarg (t, 1)); | |
f83e6885 | 1194 | return cxx_eval_constant_expression (ctx, arg, |
00f21715 | 1195 | addr, non_constant_p, |
b2a43197 | 1196 | overflow_p); |
09b42213 | 1197 | } |
1198 | else if (TREE_CODE (t) == AGGR_INIT_EXPR | |
1199 | && AGGR_INIT_ZERO_FIRST (t)) | |
1200 | return build_zero_init (DECL_CONTEXT (fun), NULL_TREE, false); | |
1201 | } | |
1202 | ||
1203 | /* If in direct recursive call, optimize definition search. */ | |
cf72f34d | 1204 | if (ctx && ctx->call && ctx->call->fundef->decl == fun) |
1205 | new_call.fundef = ctx->call->fundef; | |
09b42213 | 1206 | else |
1207 | { | |
1208 | new_call.fundef = retrieve_constexpr_fundef (fun); | |
1209 | if (new_call.fundef == NULL || new_call.fundef->body == NULL) | |
1210 | { | |
f83e6885 | 1211 | if (!ctx->quiet) |
09b42213 | 1212 | { |
1213 | if (DECL_INITIAL (fun)) | |
1214 | { | |
1215 | /* The definition of fun was somehow unsuitable. */ | |
1216 | error_at (loc, "%qD called in a constant expression", fun); | |
1217 | explain_invalid_constexpr_fn (fun); | |
1218 | } | |
1219 | else | |
1220 | error_at (loc, "%qD used before its definition", fun); | |
1221 | } | |
1222 | *non_constant_p = true; | |
1223 | return t; | |
1224 | } | |
1225 | } | |
9c96033c | 1226 | |
1227 | constexpr_ctx new_ctx = *ctx; | |
1228 | if (DECL_CONSTRUCTOR_P (fun) && !ctx->object | |
1229 | && TREE_CODE (t) == AGGR_INIT_EXPR) | |
1230 | { | |
1231 | /* We want to have an initialization target for an AGGR_INIT_EXPR. | |
1232 | If we don't already have one in CTX, use the AGGR_INIT_EXPR_SLOT. */ | |
1233 | new_ctx.object = AGGR_INIT_EXPR_SLOT (t); | |
1234 | tree ctor = new_ctx.ctor = build_constructor (DECL_CONTEXT (fun), NULL); | |
1235 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor) = true; | |
1236 | ctx->values->put (new_ctx.object, ctor); | |
1237 | ctx = &new_ctx; | |
1238 | } | |
1239 | ||
cf72f34d | 1240 | cxx_bind_parameters_in_call (ctx, t, &new_call, |
f83e6885 | 1241 | non_constant_p, overflow_p); |
09b42213 | 1242 | if (*non_constant_p) |
1243 | return t; | |
1244 | ||
1245 | depth_ok = push_cx_call_context (t); | |
1246 | ||
1247 | new_call.hash | |
1248 | = iterative_hash_template_arg (new_call.bindings, | |
1249 | constexpr_fundef_hasher::hash (new_call.fundef)); | |
1250 | ||
1251 | /* If we have seen this call before, we are done. */ | |
1252 | maybe_initialize_constexpr_call_table (); | |
1253 | slot = constexpr_call_table->find_slot (&new_call, INSERT); | |
1254 | entry = *slot; | |
1255 | if (entry == NULL) | |
1256 | { | |
1257 | /* We need to keep a pointer to the entry, not just the slot, as the | |
1258 | slot can move in the call to cxx_eval_builtin_function_call. */ | |
1259 | *slot = entry = ggc_alloc<constexpr_call> (); | |
1260 | *entry = new_call; | |
1261 | } | |
1262 | /* Calls which are in progress have their result set to NULL | |
1263 | so that we can detect circular dependencies. */ | |
1264 | else if (entry->result == NULL) | |
1265 | { | |
f83e6885 | 1266 | if (!ctx->quiet) |
09b42213 | 1267 | error ("call has circular dependency"); |
1268 | *non_constant_p = true; | |
1269 | entry->result = result = error_mark_node; | |
1270 | } | |
1271 | ||
1272 | if (!depth_ok) | |
1273 | { | |
f83e6885 | 1274 | if (!ctx->quiet) |
09b42213 | 1275 | error ("constexpr evaluation depth exceeds maximum of %d (use " |
1276 | "-fconstexpr-depth= to increase the maximum)", | |
1277 | max_constexpr_depth); | |
1278 | *non_constant_p = true; | |
1279 | entry->result = result = error_mark_node; | |
1280 | } | |
1281 | else | |
1282 | { | |
1283 | result = entry->result; | |
1284 | if (!result || result == error_mark_node) | |
cf72f34d | 1285 | { |
9c96033c | 1286 | if (!use_new_call) |
1287 | { | |
1288 | new_ctx.call = &new_call; | |
1289 | result = (cxx_eval_constant_expression | |
1290 | (&new_ctx, new_call.fundef->body, | |
f83e6885 | 1291 | addr, |
b2a43197 | 1292 | non_constant_p, overflow_p)); |
9c96033c | 1293 | } |
1294 | else | |
1295 | { | |
1296 | if (DECL_SAVED_TREE (fun) == NULL_TREE | |
1297 | && (DECL_CONSTRUCTOR_P (fun) || DECL_DESTRUCTOR_P (fun))) | |
1298 | /* The maybe-in-charge 'tor had its DECL_SAVED_TREE | |
1299 | cleared, try the first clone. */ | |
1300 | fun = DECL_CHAIN (fun); | |
1301 | gcc_assert (DECL_SAVED_TREE (fun)); | |
1302 | tree parms, res; | |
1303 | ||
1304 | /* Unshare the whole function body. */ | |
1305 | tree body = copy_fn (fun, parms, res); | |
1306 | ||
1307 | /* Associate the bindings with the remapped parms. */ | |
1308 | tree bound = new_call.bindings; | |
1309 | tree remapped = parms; | |
1310 | while (bound) | |
1311 | { | |
1312 | tree oparm = TREE_PURPOSE (bound); | |
1313 | tree arg = TREE_VALUE (bound); | |
1314 | gcc_assert (DECL_NAME (remapped) == DECL_NAME (oparm)); | |
1315 | ctx->values->put (remapped, arg); | |
1316 | bound = TREE_CHAIN (bound); | |
1317 | remapped = DECL_CHAIN (remapped); | |
1318 | } | |
1319 | /* Add the RESULT_DECL to the values map, too. */ | |
1320 | tree slot = NULL_TREE; | |
1321 | if (DECL_BY_REFERENCE (res)) | |
1322 | { | |
1323 | slot = AGGR_INIT_EXPR_SLOT (t); | |
1324 | tree addr = build_address (slot); | |
1325 | addr = build_nop (TREE_TYPE (res), addr); | |
1326 | ctx->values->put (res, addr); | |
1327 | ctx->values->put (slot, NULL_TREE); | |
1328 | } | |
1329 | else | |
1330 | ctx->values->put (res, NULL_TREE); | |
1331 | ||
00f21715 | 1332 | tree jump_target = NULL_TREE; |
f83e6885 | 1333 | cxx_eval_constant_expression (ctx, body, |
00f21715 | 1334 | addr, non_constant_p, overflow_p, |
1335 | &jump_target); | |
9c96033c | 1336 | |
7321fbd5 | 1337 | if (DECL_CONSTRUCTOR_P (fun)) |
9c96033c | 1338 | /* This can be null for a subobject constructor call, in |
1339 | which case what we care about is the initialization | |
1340 | side-effects rather than the value. We could get at the | |
1341 | value by evaluating *this, but we don't bother; there's | |
1342 | no need to put such a call in the hash table. */ | |
1343 | result = addr ? ctx->object : ctx->ctor; | |
1344 | else | |
1345 | { | |
1346 | result = *ctx->values->get (slot ? slot : res); | |
da1fbe63 | 1347 | if (result == NULL_TREE && !*non_constant_p) |
9c96033c | 1348 | { |
f83e6885 | 1349 | if (!ctx->quiet) |
9c96033c | 1350 | error ("constexpr call flows off the end " |
1351 | "of the function"); | |
1352 | *non_constant_p = true; | |
1353 | } | |
1354 | } | |
1355 | ||
1356 | /* Remove the parms/result from the values map. Is it worth | |
1357 | bothering to do this when the map itself is only live for | |
1358 | one constexpr evaluation? If so, maybe also clear out | |
1359 | other vars from call, maybe in BIND_EXPR handling? */ | |
1360 | ctx->values->remove (res); | |
1361 | if (slot) | |
1362 | ctx->values->remove (slot); | |
1363 | for (tree parm = parms; parm; parm = TREE_CHAIN (parm)) | |
1364 | ctx->values->remove (parm); | |
1365 | } | |
cf72f34d | 1366 | } |
9c96033c | 1367 | |
09b42213 | 1368 | if (result == error_mark_node) |
1369 | *non_constant_p = true; | |
1370 | if (*non_constant_p) | |
1371 | entry->result = result = error_mark_node; | |
9c96033c | 1372 | else if (result) |
09b42213 | 1373 | { |
1374 | /* If this was a call to initialize an object, set the type of | |
1375 | the CONSTRUCTOR to the type of that object. */ | |
7321fbd5 | 1376 | if (DECL_CONSTRUCTOR_P (fun) && !use_new_call) |
09b42213 | 1377 | { |
1378 | tree ob_arg = get_nth_callarg (t, 0); | |
1379 | STRIP_NOPS (ob_arg); | |
1380 | gcc_assert (TYPE_PTR_P (TREE_TYPE (ob_arg)) | |
1381 | && CLASS_TYPE_P (TREE_TYPE (TREE_TYPE (ob_arg)))); | |
1382 | result = adjust_temp_type (TREE_TYPE (TREE_TYPE (ob_arg)), | |
1383 | result); | |
1384 | } | |
1385 | entry->result = result; | |
1386 | } | |
9c96033c | 1387 | else |
1388 | result = void_node; | |
09b42213 | 1389 | } |
1390 | ||
1391 | pop_cx_call_context (); | |
1392 | return unshare_expr (result); | |
1393 | } | |
1394 | ||
1395 | /* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */ | |
1396 | ||
1397 | bool | |
1398 | reduced_constant_expression_p (tree t) | |
1399 | { | |
1400 | switch (TREE_CODE (t)) | |
1401 | { | |
1402 | case PTRMEM_CST: | |
1403 | /* Even if we can't lower this yet, it's constant. */ | |
1404 | return true; | |
1405 | ||
1406 | case CONSTRUCTOR: | |
1407 | /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */ | |
1408 | tree elt; unsigned HOST_WIDE_INT idx; | |
1409 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (t), idx, elt) | |
1410 | if (!reduced_constant_expression_p (elt)) | |
1411 | return false; | |
1412 | return true; | |
1413 | ||
1414 | default: | |
1415 | /* FIXME are we calling this too much? */ | |
1416 | return initializer_constant_valid_p (t, TREE_TYPE (t)) != NULL_TREE; | |
1417 | } | |
1418 | } | |
1419 | ||
1420 | /* Some expressions may have constant operands but are not constant | |
1421 | themselves, such as 1/0. Call this function (or rather, the macro | |
1422 | following it) to check for that condition. | |
1423 | ||
1424 | We only call this in places that require an arithmetic constant, not in | |
1425 | places where we might have a non-constant expression that can be a | |
1426 | component of a constant expression, such as the address of a constexpr | |
1427 | variable that might be dereferenced later. */ | |
1428 | ||
1429 | static bool | |
1430 | verify_constant (tree t, bool allow_non_constant, bool *non_constant_p, | |
1431 | bool *overflow_p) | |
1432 | { | |
1433 | if (!*non_constant_p && !reduced_constant_expression_p (t)) | |
1434 | { | |
1435 | if (!allow_non_constant) | |
1436 | error ("%q+E is not a constant expression", t); | |
1437 | *non_constant_p = true; | |
1438 | } | |
1439 | if (TREE_OVERFLOW_P (t)) | |
1440 | { | |
1441 | if (!allow_non_constant) | |
1442 | { | |
1443 | permerror (input_location, "overflow in constant expression"); | |
1444 | /* If we're being permissive (and are in an enforcing | |
1445 | context), ignore the overflow. */ | |
1446 | if (flag_permissive) | |
1447 | return *non_constant_p; | |
1448 | } | |
1449 | *overflow_p = true; | |
1450 | } | |
1451 | return *non_constant_p; | |
1452 | } | |
1453 | ||
1454 | /* Subroutine of cxx_eval_constant_expression. | |
1455 | Attempt to reduce the unary expression tree T to a compile time value. | |
1456 | If successful, return the value. Otherwise issue a diagnostic | |
1457 | and return error_mark_node. */ | |
1458 | ||
1459 | static tree | |
cf72f34d | 1460 | cxx_eval_unary_expression (const constexpr_ctx *ctx, tree t, |
f83e6885 | 1461 | bool addr, |
09b42213 | 1462 | bool *non_constant_p, bool *overflow_p) |
1463 | { | |
1464 | tree r; | |
1465 | tree orig_arg = TREE_OPERAND (t, 0); | |
f83e6885 | 1466 | tree arg = cxx_eval_constant_expression (ctx, orig_arg, |
b2a43197 | 1467 | addr, non_constant_p, overflow_p); |
09b42213 | 1468 | VERIFY_CONSTANT (arg); |
93add516 | 1469 | location_t loc = EXPR_LOCATION (t); |
1470 | enum tree_code code = TREE_CODE (t); | |
1471 | tree type = TREE_TYPE (t); | |
1472 | r = fold_unary_loc (loc, code, type, arg); | |
1473 | if (r == NULL_TREE) | |
1474 | { | |
1475 | if (arg == orig_arg) | |
1476 | r = t; | |
1477 | else | |
1478 | r = build1_loc (loc, code, type, arg); | |
1479 | } | |
09b42213 | 1480 | VERIFY_CONSTANT (r); |
1481 | return r; | |
1482 | } | |
1483 | ||
1484 | /* Subroutine of cxx_eval_constant_expression. | |
1485 | Like cxx_eval_unary_expression, except for binary expressions. */ | |
1486 | ||
1487 | static tree | |
cf72f34d | 1488 | cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, |
f83e6885 | 1489 | bool addr, |
09b42213 | 1490 | bool *non_constant_p, bool *overflow_p) |
1491 | { | |
1492 | tree r; | |
1493 | tree orig_lhs = TREE_OPERAND (t, 0); | |
1494 | tree orig_rhs = TREE_OPERAND (t, 1); | |
1495 | tree lhs, rhs; | |
cf72f34d | 1496 | lhs = cxx_eval_constant_expression (ctx, orig_lhs, |
f83e6885 | 1497 | addr, |
b2a43197 | 1498 | non_constant_p, overflow_p); |
09b42213 | 1499 | VERIFY_CONSTANT (lhs); |
cf72f34d | 1500 | rhs = cxx_eval_constant_expression (ctx, orig_rhs, |
f83e6885 | 1501 | addr, |
b2a43197 | 1502 | non_constant_p, overflow_p); |
09b42213 | 1503 | VERIFY_CONSTANT (rhs); |
93add516 | 1504 | |
1505 | location_t loc = EXPR_LOCATION (t); | |
1506 | enum tree_code code = TREE_CODE (t); | |
1507 | tree type = TREE_TYPE (t); | |
1508 | r = fold_binary_loc (loc, code, type, lhs, rhs); | |
1509 | if (r == NULL_TREE) | |
1510 | { | |
1511 | if (lhs == orig_lhs && rhs == orig_rhs) | |
1512 | r = t; | |
1513 | else | |
1514 | r = build2_loc (loc, code, type, lhs, rhs); | |
1515 | } | |
09b42213 | 1516 | VERIFY_CONSTANT (r); |
1517 | return r; | |
1518 | } | |
1519 | ||
1520 | /* Subroutine of cxx_eval_constant_expression. | |
1521 | Attempt to evaluate condition expressions. Dead branches are not | |
1522 | looked into. */ | |
1523 | ||
1524 | static tree | |
cf72f34d | 1525 | cxx_eval_conditional_expression (const constexpr_ctx *ctx, tree t, |
f83e6885 | 1526 | bool addr, |
00f21715 | 1527 | bool *non_constant_p, bool *overflow_p, |
1528 | tree *jump_target) | |
09b42213 | 1529 | { |
cf72f34d | 1530 | tree val = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
f83e6885 | 1531 | addr, |
b2a43197 | 1532 | non_constant_p, overflow_p); |
09b42213 | 1533 | VERIFY_CONSTANT (val); |
1534 | /* Don't VERIFY_CONSTANT the other operands. */ | |
1535 | if (integer_zerop (val)) | |
cf72f34d | 1536 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), |
f83e6885 | 1537 | addr, |
00f21715 | 1538 | non_constant_p, overflow_p, |
1539 | jump_target); | |
cf72f34d | 1540 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 1541 | addr, |
00f21715 | 1542 | non_constant_p, overflow_p, |
1543 | jump_target); | |
09b42213 | 1544 | } |
1545 | ||
1546 | /* Subroutine of cxx_eval_constant_expression. | |
1547 | Attempt to reduce a reference to an array slot. */ | |
1548 | ||
1549 | static tree | |
cf72f34d | 1550 | cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, |
f83e6885 | 1551 | bool addr, |
09b42213 | 1552 | bool *non_constant_p, bool *overflow_p) |
1553 | { | |
1554 | tree oldary = TREE_OPERAND (t, 0); | |
cf72f34d | 1555 | tree ary = cxx_eval_constant_expression (ctx, oldary, |
f83e6885 | 1556 | addr, |
b2a43197 | 1557 | non_constant_p, overflow_p); |
09b42213 | 1558 | tree index, oldidx; |
1559 | HOST_WIDE_INT i; | |
1560 | tree elem_type; | |
1561 | unsigned len, elem_nchars = 1; | |
1562 | if (*non_constant_p) | |
1563 | return t; | |
1564 | oldidx = TREE_OPERAND (t, 1); | |
cf72f34d | 1565 | index = cxx_eval_constant_expression (ctx, oldidx, |
f83e6885 | 1566 | false, |
b2a43197 | 1567 | non_constant_p, overflow_p); |
09b42213 | 1568 | VERIFY_CONSTANT (index); |
1569 | if (addr && ary == oldary && index == oldidx) | |
1570 | return t; | |
1571 | else if (addr) | |
1572 | return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL); | |
1573 | elem_type = TREE_TYPE (TREE_TYPE (ary)); | |
1574 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
1575 | len = CONSTRUCTOR_NELTS (ary); | |
1576 | else if (TREE_CODE (ary) == STRING_CST) | |
1577 | { | |
1578 | elem_nchars = (TYPE_PRECISION (elem_type) | |
1579 | / TYPE_PRECISION (char_type_node)); | |
1580 | len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars; | |
1581 | } | |
1582 | else | |
1583 | { | |
1584 | /* We can't do anything with other tree codes, so use | |
1585 | VERIFY_CONSTANT to complain and fail. */ | |
1586 | VERIFY_CONSTANT (ary); | |
1587 | gcc_unreachable (); | |
1588 | } | |
1589 | if (compare_tree_int (index, len) >= 0) | |
1590 | { | |
1591 | if (tree_int_cst_lt (index, array_type_nelts_top (TREE_TYPE (ary)))) | |
1592 | { | |
1593 | /* If it's within the array bounds but doesn't have an explicit | |
1594 | initializer, it's value-initialized. */ | |
1595 | tree val = build_value_init (elem_type, tf_warning_or_error); | |
cf72f34d | 1596 | return cxx_eval_constant_expression (ctx, val, |
f83e6885 | 1597 | addr, |
b2a43197 | 1598 | non_constant_p, overflow_p); |
09b42213 | 1599 | } |
1600 | ||
f83e6885 | 1601 | if (!ctx->quiet) |
09b42213 | 1602 | error ("array subscript out of bound"); |
1603 | *non_constant_p = true; | |
1604 | return t; | |
1605 | } | |
1606 | else if (tree_int_cst_lt (index, integer_zero_node)) | |
1607 | { | |
f83e6885 | 1608 | if (!ctx->quiet) |
09b42213 | 1609 | error ("negative array subscript"); |
1610 | *non_constant_p = true; | |
1611 | return t; | |
1612 | } | |
1613 | i = tree_to_shwi (index); | |
1614 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
1615 | return (*CONSTRUCTOR_ELTS (ary))[i].value; | |
1616 | else if (elem_nchars == 1) | |
1617 | return build_int_cst (cv_unqualified (TREE_TYPE (TREE_TYPE (ary))), | |
1618 | TREE_STRING_POINTER (ary)[i]); | |
1619 | else | |
1620 | { | |
1621 | tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (ary))); | |
1622 | return native_interpret_expr (type, (const unsigned char *) | |
1623 | TREE_STRING_POINTER (ary) | |
1624 | + i * elem_nchars, elem_nchars); | |
1625 | } | |
1626 | /* Don't VERIFY_CONSTANT here. */ | |
1627 | } | |
1628 | ||
1629 | /* Subroutine of cxx_eval_constant_expression. | |
1630 | Attempt to reduce a field access of a value of class type. */ | |
1631 | ||
1632 | static tree | |
cf72f34d | 1633 | cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, |
f83e6885 | 1634 | bool addr, |
09b42213 | 1635 | bool *non_constant_p, bool *overflow_p) |
1636 | { | |
1637 | unsigned HOST_WIDE_INT i; | |
1638 | tree field; | |
1639 | tree value; | |
1640 | tree part = TREE_OPERAND (t, 1); | |
1641 | tree orig_whole = TREE_OPERAND (t, 0); | |
cf72f34d | 1642 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
f83e6885 | 1643 | addr, |
b2a43197 | 1644 | non_constant_p, overflow_p); |
09b42213 | 1645 | if (whole == orig_whole) |
1646 | return t; | |
1647 | if (addr) | |
1648 | return fold_build3 (COMPONENT_REF, TREE_TYPE (t), | |
1649 | whole, part, NULL_TREE); | |
1650 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
1651 | CONSTRUCTOR. */ | |
1652 | if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR) | |
1653 | { | |
f83e6885 | 1654 | if (!ctx->quiet) |
09b42213 | 1655 | error ("%qE is not a constant expression", orig_whole); |
1656 | *non_constant_p = true; | |
1657 | } | |
1658 | if (DECL_MUTABLE_P (part)) | |
1659 | { | |
f83e6885 | 1660 | if (!ctx->quiet) |
09b42213 | 1661 | error ("mutable %qD is not usable in a constant expression", part); |
1662 | *non_constant_p = true; | |
1663 | } | |
1664 | if (*non_constant_p) | |
1665 | return t; | |
1666 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
1667 | { | |
1668 | if (field == part) | |
9c96033c | 1669 | { |
1670 | if (value) | |
1671 | return value; | |
1672 | else | |
1673 | /* We're in the middle of initializing it. */ | |
1674 | break; | |
1675 | } | |
09b42213 | 1676 | } |
1677 | if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE | |
1678 | && CONSTRUCTOR_NELTS (whole) > 0) | |
1679 | { | |
1680 | /* DR 1188 says we don't have to deal with this. */ | |
f83e6885 | 1681 | if (!ctx->quiet) |
09b42213 | 1682 | error ("accessing %qD member instead of initialized %qD member in " |
1683 | "constant expression", part, CONSTRUCTOR_ELT (whole, 0)->index); | |
1684 | *non_constant_p = true; | |
1685 | return t; | |
1686 | } | |
1687 | ||
cf72f34d | 1688 | if (CONSTRUCTOR_NO_IMPLICIT_ZERO (whole)) |
1689 | { | |
1690 | /* 'whole' is part of the aggregate initializer we're currently | |
1691 | building; if there's no initializer for this member yet, that's an | |
1692 | error. */ | |
f83e6885 | 1693 | if (!ctx->quiet) |
cf72f34d | 1694 | error ("accessing uninitialized member %qD", part); |
1695 | *non_constant_p = true; | |
1696 | return t; | |
1697 | } | |
1698 | ||
09b42213 | 1699 | /* If there's no explicit init for this field, it's value-initialized. */ |
1700 | value = build_value_init (TREE_TYPE (t), tf_warning_or_error); | |
cf72f34d | 1701 | return cxx_eval_constant_expression (ctx, value, |
f83e6885 | 1702 | addr, |
b2a43197 | 1703 | non_constant_p, overflow_p); |
09b42213 | 1704 | } |
1705 | ||
1706 | /* Subroutine of cxx_eval_constant_expression. | |
1707 | Attempt to reduce a field access of a value of class type that is | |
1708 | expressed as a BIT_FIELD_REF. */ | |
1709 | ||
1710 | static tree | |
cf72f34d | 1711 | cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, |
f83e6885 | 1712 | bool addr, |
09b42213 | 1713 | bool *non_constant_p, bool *overflow_p) |
1714 | { | |
1715 | tree orig_whole = TREE_OPERAND (t, 0); | |
1716 | tree retval, fldval, utype, mask; | |
1717 | bool fld_seen = false; | |
1718 | HOST_WIDE_INT istart, isize; | |
cf72f34d | 1719 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
f83e6885 | 1720 | addr, |
b2a43197 | 1721 | non_constant_p, overflow_p); |
09b42213 | 1722 | tree start, field, value; |
1723 | unsigned HOST_WIDE_INT i; | |
1724 | ||
1725 | if (whole == orig_whole) | |
1726 | return t; | |
1727 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
1728 | CONSTRUCTOR. */ | |
1729 | if (!*non_constant_p | |
1730 | && TREE_CODE (whole) != VECTOR_CST | |
1731 | && TREE_CODE (whole) != CONSTRUCTOR) | |
1732 | { | |
f83e6885 | 1733 | if (!ctx->quiet) |
09b42213 | 1734 | error ("%qE is not a constant expression", orig_whole); |
1735 | *non_constant_p = true; | |
1736 | } | |
1737 | if (*non_constant_p) | |
1738 | return t; | |
1739 | ||
1740 | if (TREE_CODE (whole) == VECTOR_CST) | |
1741 | return fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole, | |
1742 | TREE_OPERAND (t, 1), TREE_OPERAND (t, 2)); | |
1743 | ||
1744 | start = TREE_OPERAND (t, 2); | |
1745 | istart = tree_to_shwi (start); | |
1746 | isize = tree_to_shwi (TREE_OPERAND (t, 1)); | |
1747 | utype = TREE_TYPE (t); | |
1748 | if (!TYPE_UNSIGNED (utype)) | |
1749 | utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1); | |
1750 | retval = build_int_cst (utype, 0); | |
1751 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
1752 | { | |
1753 | tree bitpos = bit_position (field); | |
1754 | if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1)) | |
1755 | return value; | |
1756 | if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE | |
1757 | && TREE_CODE (value) == INTEGER_CST | |
1758 | && tree_fits_shwi_p (bitpos) | |
1759 | && tree_fits_shwi_p (DECL_SIZE (field))) | |
1760 | { | |
1761 | HOST_WIDE_INT bit = tree_to_shwi (bitpos); | |
1762 | HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field)); | |
1763 | HOST_WIDE_INT shift; | |
1764 | if (bit >= istart && bit + sz <= istart + isize) | |
1765 | { | |
1766 | fldval = fold_convert (utype, value); | |
1767 | mask = build_int_cst_type (utype, -1); | |
1768 | mask = fold_build2 (LSHIFT_EXPR, utype, mask, | |
1769 | size_int (TYPE_PRECISION (utype) - sz)); | |
1770 | mask = fold_build2 (RSHIFT_EXPR, utype, mask, | |
1771 | size_int (TYPE_PRECISION (utype) - sz)); | |
1772 | fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask); | |
1773 | shift = bit - istart; | |
1774 | if (BYTES_BIG_ENDIAN) | |
1775 | shift = TYPE_PRECISION (utype) - shift - sz; | |
1776 | fldval = fold_build2 (LSHIFT_EXPR, utype, fldval, | |
1777 | size_int (shift)); | |
1778 | retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval); | |
1779 | fld_seen = true; | |
1780 | } | |
1781 | } | |
1782 | } | |
1783 | if (fld_seen) | |
1784 | return fold_convert (TREE_TYPE (t), retval); | |
1785 | gcc_unreachable (); | |
1786 | return error_mark_node; | |
1787 | } | |
1788 | ||
1789 | /* Subroutine of cxx_eval_constant_expression. | |
1790 | Evaluate a short-circuited logical expression T in the context | |
1791 | of a given constexpr CALL. BAILOUT_VALUE is the value for | |
1792 | early return. CONTINUE_VALUE is used here purely for | |
1793 | sanity check purposes. */ | |
1794 | ||
1795 | static tree | |
cf72f34d | 1796 | cxx_eval_logical_expression (const constexpr_ctx *ctx, tree t, |
09b42213 | 1797 | tree bailout_value, tree continue_value, |
f83e6885 | 1798 | bool addr, |
09b42213 | 1799 | bool *non_constant_p, bool *overflow_p) |
1800 | { | |
1801 | tree r; | |
cf72f34d | 1802 | tree lhs = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
f83e6885 | 1803 | addr, |
b2a43197 | 1804 | non_constant_p, overflow_p); |
09b42213 | 1805 | VERIFY_CONSTANT (lhs); |
1806 | if (tree_int_cst_equal (lhs, bailout_value)) | |
1807 | return lhs; | |
1808 | gcc_assert (tree_int_cst_equal (lhs, continue_value)); | |
cf72f34d | 1809 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 1810 | addr, non_constant_p, |
b2a43197 | 1811 | overflow_p); |
09b42213 | 1812 | VERIFY_CONSTANT (r); |
1813 | return r; | |
1814 | } | |
1815 | ||
1816 | /* REF is a COMPONENT_REF designating a particular field. V is a vector of | |
1817 | CONSTRUCTOR elements to initialize (part of) an object containing that | |
1818 | field. Return a pointer to the constructor_elt corresponding to the | |
1819 | initialization of the field. */ | |
1820 | ||
1821 | static constructor_elt * | |
1822 | base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref) | |
1823 | { | |
1824 | tree aggr = TREE_OPERAND (ref, 0); | |
1825 | tree field = TREE_OPERAND (ref, 1); | |
1826 | HOST_WIDE_INT i; | |
1827 | constructor_elt *ce; | |
1828 | ||
1829 | gcc_assert (TREE_CODE (ref) == COMPONENT_REF); | |
1830 | ||
1831 | if (TREE_CODE (aggr) == COMPONENT_REF) | |
1832 | { | |
1833 | constructor_elt *base_ce | |
1834 | = base_field_constructor_elt (v, aggr); | |
1835 | v = CONSTRUCTOR_ELTS (base_ce->value); | |
1836 | } | |
1837 | ||
1838 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
1839 | if (ce->index == field) | |
1840 | return ce; | |
1841 | ||
1842 | gcc_unreachable (); | |
1843 | return NULL; | |
1844 | } | |
1845 | ||
cf72f34d | 1846 | /* Some of the expressions fed to the constexpr mechanism are calls to |
1847 | constructors, which have type void. In that case, return the type being | |
1848 | initialized by the constructor. */ | |
1849 | ||
1850 | static tree | |
1851 | initialized_type (tree t) | |
1852 | { | |
1853 | if (TYPE_P (t)) | |
1854 | return t; | |
1855 | tree type = cv_unqualified (TREE_TYPE (t)); | |
1856 | if (TREE_CODE (t) == CALL_EXPR || TREE_CODE (t) == AGGR_INIT_EXPR) | |
1857 | { | |
1858 | /* A constructor call has void type, so we need to look deeper. */ | |
1859 | tree fn = get_function_named_in_call (t); | |
1860 | if (fn && TREE_CODE (fn) == FUNCTION_DECL | |
1861 | && DECL_CXX_CONSTRUCTOR_P (fn)) | |
1862 | type = DECL_CONTEXT (fn); | |
1863 | } | |
1864 | return type; | |
1865 | } | |
1866 | ||
1867 | /* We're about to initialize element INDEX of an array or class from VALUE. | |
1868 | Set up NEW_CTX appropriately by adjusting .object to refer to the | |
1869 | subobject and creating a new CONSTRUCTOR if the element is itself | |
1870 | a class or array. */ | |
1871 | ||
1872 | static void | |
1873 | init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, | |
1874 | tree index, tree &value) | |
1875 | { | |
1876 | new_ctx = *ctx; | |
1877 | ||
1878 | if (index && TREE_CODE (index) != INTEGER_CST | |
1879 | && TREE_CODE (index) != FIELD_DECL) | |
1880 | /* This won't have an element in the new CONSTRUCTOR. */ | |
1881 | return; | |
1882 | ||
1883 | tree type = initialized_type (value); | |
1884 | if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) | |
1885 | /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ | |
1886 | return; | |
1887 | ||
1888 | /* The sub-aggregate initializer might contain a placeholder; | |
1889 | update object to refer to the subobject and ctor to refer to | |
1890 | the (newly created) sub-initializer. */ | |
1891 | if (ctx->object) | |
1892 | new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); | |
1893 | tree elt = build_constructor (type, NULL); | |
1894 | CONSTRUCTOR_NO_IMPLICIT_ZERO (elt) = true; | |
1895 | new_ctx.ctor = elt; | |
1896 | ||
1897 | if (TREE_CODE (value) == TARGET_EXPR) | |
1898 | /* Avoid creating another CONSTRUCTOR when we expand the TARGET_EXPR. */ | |
1899 | value = TARGET_EXPR_INITIAL (value); | |
1900 | } | |
1901 | ||
1902 | /* We're about to process an initializer for a class or array TYPE. Make | |
1903 | sure that CTX is set up appropriately. */ | |
1904 | ||
1905 | static void | |
1906 | verify_ctor_sanity (const constexpr_ctx *ctx, tree type) | |
1907 | { | |
1908 | /* We don't bother building a ctor for an empty base subobject. */ | |
1909 | if (is_empty_class (type)) | |
1910 | return; | |
1911 | ||
1912 | /* We're in the middle of an initializer that might involve placeholders; | |
1913 | our caller should have created a CONSTRUCTOR for us to put the | |
1914 | initializer into. We will either return that constructor or T. */ | |
1915 | gcc_assert (ctx->ctor); | |
1916 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
1917 | (type, TREE_TYPE (ctx->ctor))); | |
1918 | gcc_assert (CONSTRUCTOR_NELTS (ctx->ctor) == 0); | |
1919 | if (ctx->object) | |
1920 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
1921 | (type, TREE_TYPE (ctx->object))); | |
1922 | gcc_assert (!ctx->object || !DECL_P (ctx->object) | |
1923 | || *(ctx->values->get (ctx->object)) == ctx->ctor); | |
1924 | } | |
1925 | ||
09b42213 | 1926 | /* Subroutine of cxx_eval_constant_expression. |
1927 | The expression tree T denotes a C-style array or a C-style | |
1928 | aggregate. Reduce it to a constant expression. */ | |
1929 | ||
1930 | static tree | |
cf72f34d | 1931 | cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, |
f83e6885 | 1932 | bool addr, |
09b42213 | 1933 | bool *non_constant_p, bool *overflow_p) |
1934 | { | |
1935 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
09b42213 | 1936 | bool changed = false; |
1937 | gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t)); | |
cf72f34d | 1938 | |
1939 | verify_ctor_sanity (ctx, TREE_TYPE (t)); | |
1940 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
1941 | vec_alloc (*p, vec_safe_length (v)); | |
1942 | ||
1943 | unsigned i; tree index, value; | |
1944 | FOR_EACH_CONSTRUCTOR_ELT (v, i, index, value) | |
09b42213 | 1945 | { |
cf72f34d | 1946 | constexpr_ctx new_ctx; |
1947 | init_subob_ctx (ctx, new_ctx, index, value); | |
1948 | if (new_ctx.ctor != ctx->ctor) | |
1949 | /* If we built a new CONSTRUCTOR, attach it now so that other | |
1950 | initializers can refer to it. */ | |
1951 | CONSTRUCTOR_APPEND_ELT (*p, index, new_ctx.ctor); | |
1952 | tree elt = cxx_eval_constant_expression (&new_ctx, value, | |
f83e6885 | 1953 | addr, |
b2a43197 | 1954 | non_constant_p, overflow_p); |
09b42213 | 1955 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 1956 | if (ctx->quiet && *non_constant_p) |
cf72f34d | 1957 | break; |
1958 | if (elt != value) | |
09b42213 | 1959 | changed = true; |
cf72f34d | 1960 | if (index && TREE_CODE (index) == COMPONENT_REF) |
09b42213 | 1961 | { |
1962 | /* This is an initialization of a vfield inside a base | |
1963 | subaggregate that we already initialized; push this | |
1964 | initialization into the previous initialization. */ | |
cf72f34d | 1965 | constructor_elt *inner = base_field_constructor_elt (*p, index); |
09b42213 | 1966 | inner->value = elt; |
cf72f34d | 1967 | changed = true; |
09b42213 | 1968 | } |
cf72f34d | 1969 | else if (index |
1970 | && (TREE_CODE (index) == NOP_EXPR | |
1971 | || TREE_CODE (index) == POINTER_PLUS_EXPR)) | |
09b42213 | 1972 | { |
1973 | /* This is an initializer for an empty base; now that we've | |
1974 | checked that it's constant, we can ignore it. */ | |
cf72f34d | 1975 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (index)))); |
1976 | changed = true; | |
1977 | } | |
1978 | else if (new_ctx.ctor != ctx->ctor) | |
1979 | { | |
1980 | /* We appended this element above; update the value. */ | |
1981 | gcc_assert ((*p)->last().index == index); | |
1982 | (*p)->last().value = elt; | |
09b42213 | 1983 | } |
1984 | else | |
cf72f34d | 1985 | CONSTRUCTOR_APPEND_ELT (*p, index, elt); |
09b42213 | 1986 | } |
1987 | if (*non_constant_p || !changed) | |
cf72f34d | 1988 | return t; |
1989 | t = ctx->ctor; | |
1990 | /* We're done building this CONSTRUCTOR, so now we can interpret an | |
1991 | element without an explicit initializer as value-initialized. */ | |
1992 | CONSTRUCTOR_NO_IMPLICIT_ZERO (t) = false; | |
09b42213 | 1993 | if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE) |
1994 | t = fold (t); | |
1995 | return t; | |
1996 | } | |
1997 | ||
1998 | /* Subroutine of cxx_eval_constant_expression. | |
1999 | The expression tree T is a VEC_INIT_EXPR which denotes the desired | |
2000 | initialization of a non-static data member of array type. Reduce it to a | |
2001 | CONSTRUCTOR. | |
2002 | ||
2003 | Note that apart from value-initialization (when VALUE_INIT is true), | |
2004 | this is only intended to support value-initialization and the | |
2005 | initializations done by defaulted constructors for classes with | |
2006 | non-static data members of array type. In this case, VEC_INIT_EXPR_INIT | |
2007 | will either be NULL_TREE for the default constructor, or a COMPONENT_REF | |
2008 | for the copy/move constructor. */ | |
2009 | ||
2010 | static tree | |
cf72f34d | 2011 | cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, |
f83e6885 | 2012 | bool value_init, bool addr, |
09b42213 | 2013 | bool *non_constant_p, bool *overflow_p) |
2014 | { | |
2015 | tree elttype = TREE_TYPE (atype); | |
3e520b97 | 2016 | unsigned HOST_WIDE_INT max = tree_to_uhwi (array_type_nelts_top (atype)); |
cf72f34d | 2017 | verify_ctor_sanity (ctx, atype); |
2018 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
2019 | vec_alloc (*p, max + 1); | |
09b42213 | 2020 | bool pre_init = false; |
3e520b97 | 2021 | unsigned HOST_WIDE_INT i; |
09b42213 | 2022 | |
2023 | /* For the default constructor, build up a call to the default | |
2024 | constructor of the element type. We only need to handle class types | |
2025 | here, as for a constructor to be constexpr, all members must be | |
2026 | initialized, which for a defaulted default constructor means they must | |
2027 | be of a class type with a constexpr default constructor. */ | |
2028 | if (TREE_CODE (elttype) == ARRAY_TYPE) | |
2029 | /* We only do this at the lowest level. */; | |
2030 | else if (value_init) | |
2031 | { | |
2032 | init = build_value_init (elttype, tf_warning_or_error); | |
09b42213 | 2033 | pre_init = true; |
2034 | } | |
2035 | else if (!init) | |
2036 | { | |
2037 | vec<tree, va_gc> *argvec = make_tree_vector (); | |
2038 | init = build_special_member_call (NULL_TREE, complete_ctor_identifier, | |
2039 | &argvec, elttype, LOOKUP_NORMAL, | |
2040 | tf_warning_or_error); | |
2041 | release_tree_vector (argvec); | |
9c96033c | 2042 | init = build_aggr_init_expr (TREE_TYPE (init), init); |
09b42213 | 2043 | pre_init = true; |
2044 | } | |
2045 | ||
3e520b97 | 2046 | for (i = 0; i < max; ++i) |
09b42213 | 2047 | { |
2048 | tree idx = build_int_cst (size_type_node, i); | |
2049 | tree eltinit; | |
cf72f34d | 2050 | constexpr_ctx new_ctx; |
2051 | init_subob_ctx (ctx, new_ctx, idx, pre_init ? init : elttype); | |
2052 | if (new_ctx.ctor != ctx->ctor) | |
2053 | CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor); | |
09b42213 | 2054 | if (TREE_CODE (elttype) == ARRAY_TYPE) |
2055 | { | |
2056 | /* A multidimensional array; recurse. */ | |
2057 | if (value_init || init == NULL_TREE) | |
2058 | eltinit = NULL_TREE; | |
2059 | else | |
2060 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2061 | tf_warning_or_error); | |
cf72f34d | 2062 | eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, value_init, |
f83e6885 | 2063 | addr, |
09b42213 | 2064 | non_constant_p, overflow_p); |
2065 | } | |
2066 | else if (pre_init) | |
2067 | { | |
2068 | /* Initializing an element using value or default initialization | |
2069 | we just pre-built above. */ | |
cf72f34d | 2070 | eltinit = (cxx_eval_constant_expression |
f83e6885 | 2071 | (&new_ctx, init, |
b2a43197 | 2072 | addr, non_constant_p, overflow_p)); |
09b42213 | 2073 | } |
2074 | else | |
2075 | { | |
2076 | /* Copying an element. */ | |
2077 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2078 | (atype, TREE_TYPE (init))); | |
2079 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2080 | tf_warning_or_error); | |
2081 | if (!real_lvalue_p (init)) | |
2082 | eltinit = move (eltinit); | |
2083 | eltinit = force_rvalue (eltinit, tf_warning_or_error); | |
cf72f34d | 2084 | eltinit = (cxx_eval_constant_expression |
f83e6885 | 2085 | (&new_ctx, eltinit, addr, |
b2a43197 | 2086 | non_constant_p, overflow_p)); |
09b42213 | 2087 | } |
f83e6885 | 2088 | if (*non_constant_p && !ctx->quiet) |
cf72f34d | 2089 | break; |
2090 | if (new_ctx.ctor != ctx->ctor) | |
2091 | { | |
2092 | /* We appended this element above; update the value. */ | |
2093 | gcc_assert ((*p)->last().index == idx); | |
2094 | (*p)->last().value = eltinit; | |
2095 | } | |
2096 | else | |
2097 | CONSTRUCTOR_APPEND_ELT (*p, idx, eltinit); | |
09b42213 | 2098 | } |
2099 | ||
2100 | if (!*non_constant_p) | |
2101 | { | |
cf72f34d | 2102 | init = ctx->ctor; |
2103 | CONSTRUCTOR_NO_IMPLICIT_ZERO (init) = false; | |
09b42213 | 2104 | } |
09b42213 | 2105 | return init; |
2106 | } | |
2107 | ||
2108 | static tree | |
cf72f34d | 2109 | cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, |
f83e6885 | 2110 | bool addr, |
09b42213 | 2111 | bool *non_constant_p, bool *overflow_p) |
2112 | { | |
2113 | tree atype = TREE_TYPE (t); | |
2114 | tree init = VEC_INIT_EXPR_INIT (t); | |
cf72f34d | 2115 | tree r = cxx_eval_vec_init_1 (ctx, atype, init, |
09b42213 | 2116 | VEC_INIT_EXPR_VALUE_INIT (t), |
f83e6885 | 2117 | addr, non_constant_p, overflow_p); |
09b42213 | 2118 | if (*non_constant_p) |
2119 | return t; | |
2120 | else | |
2121 | return r; | |
2122 | } | |
2123 | ||
2124 | /* A less strict version of fold_indirect_ref_1, which requires cv-quals to | |
2125 | match. We want to be less strict for simple *& folding; if we have a | |
2126 | non-const temporary that we access through a const pointer, that should | |
2127 | work. We handle this here rather than change fold_indirect_ref_1 | |
2128 | because we're dealing with things like ADDR_EXPR of INTEGER_CST which | |
2129 | don't really make sense outside of constant expression evaluation. Also | |
2130 | we want to allow folding to COMPONENT_REF, which could cause trouble | |
2131 | with TBAA in fold_indirect_ref_1. | |
2132 | ||
2133 | Try to keep this function synced with fold_indirect_ref_1. */ | |
2134 | ||
2135 | static tree | |
2136 | cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) | |
2137 | { | |
2138 | tree sub, subtype; | |
2139 | ||
2140 | sub = op0; | |
2141 | STRIP_NOPS (sub); | |
2142 | subtype = TREE_TYPE (sub); | |
2143 | if (!POINTER_TYPE_P (subtype)) | |
2144 | return NULL_TREE; | |
2145 | ||
2146 | if (TREE_CODE (sub) == ADDR_EXPR) | |
2147 | { | |
2148 | tree op = TREE_OPERAND (sub, 0); | |
2149 | tree optype = TREE_TYPE (op); | |
2150 | ||
2151 | /* *&CONST_DECL -> to the value of the const decl. */ | |
2152 | if (TREE_CODE (op) == CONST_DECL) | |
2153 | return DECL_INITIAL (op); | |
2154 | /* *&p => p; make sure to handle *&"str"[cst] here. */ | |
2155 | if (same_type_ignoring_top_level_qualifiers_p (optype, type)) | |
2156 | { | |
2157 | tree fop = fold_read_from_constant_string (op); | |
2158 | if (fop) | |
2159 | return fop; | |
2160 | else | |
2161 | return op; | |
2162 | } | |
2163 | /* *(foo *)&fooarray => fooarray[0] */ | |
2164 | else if (TREE_CODE (optype) == ARRAY_TYPE | |
2165 | && (same_type_ignoring_top_level_qualifiers_p | |
2166 | (type, TREE_TYPE (optype)))) | |
2167 | { | |
2168 | tree type_domain = TYPE_DOMAIN (optype); | |
2169 | tree min_val = size_zero_node; | |
2170 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
2171 | min_val = TYPE_MIN_VALUE (type_domain); | |
2172 | return build4_loc (loc, ARRAY_REF, type, op, min_val, | |
2173 | NULL_TREE, NULL_TREE); | |
2174 | } | |
2175 | /* *(foo *)&complexfoo => __real__ complexfoo */ | |
2176 | else if (TREE_CODE (optype) == COMPLEX_TYPE | |
2177 | && (same_type_ignoring_top_level_qualifiers_p | |
2178 | (type, TREE_TYPE (optype)))) | |
2179 | return fold_build1_loc (loc, REALPART_EXPR, type, op); | |
2180 | /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */ | |
2181 | else if (TREE_CODE (optype) == VECTOR_TYPE | |
2182 | && (same_type_ignoring_top_level_qualifiers_p | |
2183 | (type, TREE_TYPE (optype)))) | |
2184 | { | |
2185 | tree part_width = TYPE_SIZE (type); | |
2186 | tree index = bitsize_int (0); | |
2187 | return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, index); | |
2188 | } | |
2189 | /* Also handle conversion to an empty base class, which | |
2190 | is represented with a NOP_EXPR. */ | |
2191 | else if (is_empty_class (type) | |
2192 | && CLASS_TYPE_P (optype) | |
2193 | && DERIVED_FROM_P (type, optype)) | |
2194 | { | |
2195 | *empty_base = true; | |
2196 | return op; | |
2197 | } | |
2198 | /* *(foo *)&struct_with_foo_field => COMPONENT_REF */ | |
2199 | else if (RECORD_OR_UNION_TYPE_P (optype)) | |
2200 | { | |
2201 | tree field = TYPE_FIELDS (optype); | |
2202 | for (; field; field = DECL_CHAIN (field)) | |
2203 | if (TREE_CODE (field) == FIELD_DECL | |
2204 | && integer_zerop (byte_position (field)) | |
2205 | && (same_type_ignoring_top_level_qualifiers_p | |
2206 | (TREE_TYPE (field), type))) | |
2207 | { | |
2208 | return fold_build3 (COMPONENT_REF, type, op, field, NULL_TREE); | |
2209 | break; | |
2210 | } | |
2211 | } | |
2212 | } | |
2213 | else if (TREE_CODE (sub) == POINTER_PLUS_EXPR | |
2214 | && TREE_CODE (TREE_OPERAND (sub, 1)) == INTEGER_CST) | |
2215 | { | |
2216 | tree op00 = TREE_OPERAND (sub, 0); | |
2217 | tree op01 = TREE_OPERAND (sub, 1); | |
2218 | ||
2219 | STRIP_NOPS (op00); | |
2220 | if (TREE_CODE (op00) == ADDR_EXPR) | |
2221 | { | |
2222 | tree op00type; | |
2223 | op00 = TREE_OPERAND (op00, 0); | |
2224 | op00type = TREE_TYPE (op00); | |
2225 | ||
2226 | /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */ | |
2227 | if (TREE_CODE (op00type) == VECTOR_TYPE | |
2228 | && (same_type_ignoring_top_level_qualifiers_p | |
2229 | (type, TREE_TYPE (op00type)))) | |
2230 | { | |
2231 | HOST_WIDE_INT offset = tree_to_shwi (op01); | |
2232 | tree part_width = TYPE_SIZE (type); | |
2233 | unsigned HOST_WIDE_INT part_widthi = tree_to_shwi (part_width)/BITS_PER_UNIT; | |
2234 | unsigned HOST_WIDE_INT indexi = offset * BITS_PER_UNIT; | |
2235 | tree index = bitsize_int (indexi); | |
2236 | ||
2237 | if (offset / part_widthi < TYPE_VECTOR_SUBPARTS (op00type)) | |
2238 | return fold_build3_loc (loc, | |
2239 | BIT_FIELD_REF, type, op00, | |
2240 | part_width, index); | |
2241 | ||
2242 | } | |
2243 | /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ | |
2244 | else if (TREE_CODE (op00type) == COMPLEX_TYPE | |
2245 | && (same_type_ignoring_top_level_qualifiers_p | |
2246 | (type, TREE_TYPE (op00type)))) | |
2247 | { | |
2248 | tree size = TYPE_SIZE_UNIT (type); | |
2249 | if (tree_int_cst_equal (size, op01)) | |
2250 | return fold_build1_loc (loc, IMAGPART_EXPR, type, op00); | |
2251 | } | |
2252 | /* ((foo *)&fooarray)[1] => fooarray[1] */ | |
2253 | else if (TREE_CODE (op00type) == ARRAY_TYPE | |
2254 | && (same_type_ignoring_top_level_qualifiers_p | |
2255 | (type, TREE_TYPE (op00type)))) | |
2256 | { | |
2257 | tree type_domain = TYPE_DOMAIN (op00type); | |
2258 | tree min_val = size_zero_node; | |
2259 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
2260 | min_val = TYPE_MIN_VALUE (type_domain); | |
2261 | op01 = size_binop_loc (loc, EXACT_DIV_EXPR, op01, | |
2262 | TYPE_SIZE_UNIT (type)); | |
2263 | op01 = size_binop_loc (loc, PLUS_EXPR, op01, min_val); | |
2264 | return build4_loc (loc, ARRAY_REF, type, op00, op01, | |
2265 | NULL_TREE, NULL_TREE); | |
2266 | } | |
2267 | /* Also handle conversion to an empty base class, which | |
2268 | is represented with a NOP_EXPR. */ | |
2269 | else if (is_empty_class (type) | |
2270 | && CLASS_TYPE_P (op00type) | |
2271 | && DERIVED_FROM_P (type, op00type)) | |
2272 | { | |
2273 | *empty_base = true; | |
2274 | return op00; | |
2275 | } | |
2276 | /* ((foo *)&struct_with_foo_field)[1] => COMPONENT_REF */ | |
2277 | else if (RECORD_OR_UNION_TYPE_P (op00type)) | |
2278 | { | |
2279 | tree field = TYPE_FIELDS (op00type); | |
2280 | for (; field; field = DECL_CHAIN (field)) | |
2281 | if (TREE_CODE (field) == FIELD_DECL | |
2282 | && tree_int_cst_equal (byte_position (field), op01) | |
2283 | && (same_type_ignoring_top_level_qualifiers_p | |
2284 | (TREE_TYPE (field), type))) | |
2285 | { | |
2286 | return fold_build3 (COMPONENT_REF, type, op00, | |
2287 | field, NULL_TREE); | |
2288 | break; | |
2289 | } | |
2290 | } | |
2291 | } | |
2292 | } | |
2293 | /* *(foo *)fooarrptr => (*fooarrptr)[0] */ | |
2294 | else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE | |
2295 | && (same_type_ignoring_top_level_qualifiers_p | |
2296 | (type, TREE_TYPE (TREE_TYPE (subtype))))) | |
2297 | { | |
2298 | tree type_domain; | |
2299 | tree min_val = size_zero_node; | |
2300 | tree newsub = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL); | |
2301 | if (newsub) | |
2302 | sub = newsub; | |
2303 | else | |
2304 | sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub); | |
2305 | type_domain = TYPE_DOMAIN (TREE_TYPE (sub)); | |
2306 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
2307 | min_val = TYPE_MIN_VALUE (type_domain); | |
2308 | return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE, | |
2309 | NULL_TREE); | |
2310 | } | |
2311 | ||
2312 | return NULL_TREE; | |
2313 | } | |
2314 | ||
2315 | static tree | |
cf72f34d | 2316 | cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, |
f83e6885 | 2317 | bool addr, |
09b42213 | 2318 | bool *non_constant_p, bool *overflow_p) |
2319 | { | |
2320 | tree orig_op0 = TREE_OPERAND (t, 0); | |
f83e6885 | 2321 | tree op0 = cxx_eval_constant_expression (ctx, orig_op0, |
00f21715 | 2322 | /*addr*/false, non_constant_p, |
b2a43197 | 2323 | overflow_p); |
09b42213 | 2324 | bool empty_base = false; |
2325 | tree r; | |
2326 | ||
2327 | /* Don't VERIFY_CONSTANT here. */ | |
2328 | if (*non_constant_p) | |
2329 | return t; | |
2330 | ||
2331 | r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), op0, | |
2332 | &empty_base); | |
2333 | ||
2334 | if (r) | |
f83e6885 | 2335 | r = cxx_eval_constant_expression (ctx, r, |
b2a43197 | 2336 | addr, non_constant_p, overflow_p); |
09b42213 | 2337 | else |
2338 | { | |
2339 | tree sub = op0; | |
2340 | STRIP_NOPS (sub); | |
2341 | if (TREE_CODE (sub) == ADDR_EXPR) | |
2342 | { | |
2343 | /* We couldn't fold to a constant value. Make sure it's not | |
2344 | something we should have been able to fold. */ | |
2345 | gcc_assert (!same_type_ignoring_top_level_qualifiers_p | |
2346 | (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t))); | |
2347 | /* DR 1188 says we don't have to deal with this. */ | |
f83e6885 | 2348 | if (!ctx->quiet) |
09b42213 | 2349 | error ("accessing value of %qE through a %qT glvalue in a " |
2350 | "constant expression", build_fold_indirect_ref (sub), | |
2351 | TREE_TYPE (t)); | |
2352 | *non_constant_p = true; | |
2353 | return t; | |
2354 | } | |
2355 | } | |
2356 | ||
2357 | /* If we're pulling out the value of an empty base, make sure | |
2358 | that the whole object is constant and then return an empty | |
2359 | CONSTRUCTOR. */ | |
9c96033c | 2360 | if (empty_base && !addr) |
09b42213 | 2361 | { |
2362 | VERIFY_CONSTANT (r); | |
2363 | r = build_constructor (TREE_TYPE (t), NULL); | |
2364 | TREE_CONSTANT (r) = true; | |
2365 | } | |
2366 | ||
2367 | if (r == NULL_TREE) | |
2368 | { | |
2369 | if (addr && op0 != orig_op0) | |
2370 | return build1 (INDIRECT_REF, TREE_TYPE (t), op0); | |
2371 | if (!addr) | |
2372 | VERIFY_CONSTANT (t); | |
2373 | return t; | |
2374 | } | |
2375 | return r; | |
2376 | } | |
2377 | ||
2378 | /* Complain about R, a VAR_DECL, not being usable in a constant expression. | |
2379 | Shared between potential_constant_expression and | |
2380 | cxx_eval_constant_expression. */ | |
2381 | ||
2382 | static void | |
2383 | non_const_var_error (tree r) | |
2384 | { | |
2385 | tree type = TREE_TYPE (r); | |
2386 | error ("the value of %qD is not usable in a constant " | |
2387 | "expression", r); | |
2388 | /* Avoid error cascade. */ | |
2389 | if (DECL_INITIAL (r) == error_mark_node) | |
2390 | return; | |
2391 | if (DECL_DECLARED_CONSTEXPR_P (r)) | |
2392 | inform (DECL_SOURCE_LOCATION (r), | |
2393 | "%qD used in its own initializer", r); | |
2394 | else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) | |
2395 | { | |
2396 | if (!CP_TYPE_CONST_P (type)) | |
2397 | inform (DECL_SOURCE_LOCATION (r), | |
2398 | "%q#D is not const", r); | |
2399 | else if (CP_TYPE_VOLATILE_P (type)) | |
2400 | inform (DECL_SOURCE_LOCATION (r), | |
2401 | "%q#D is volatile", r); | |
2402 | else if (!DECL_INITIAL (r) | |
2403 | || !TREE_CONSTANT (DECL_INITIAL (r))) | |
2404 | inform (DECL_SOURCE_LOCATION (r), | |
2405 | "%qD was not initialized with a constant " | |
2406 | "expression", r); | |
2407 | else | |
2408 | gcc_unreachable (); | |
2409 | } | |
2410 | else | |
2411 | { | |
2412 | if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r)) | |
2413 | inform (DECL_SOURCE_LOCATION (r), | |
2414 | "%qD was not declared %<constexpr%>", r); | |
2415 | else | |
2416 | inform (DECL_SOURCE_LOCATION (r), | |
2417 | "%qD does not have integral or enumeration type", | |
2418 | r); | |
2419 | } | |
2420 | } | |
2421 | ||
2422 | /* Subroutine of cxx_eval_constant_expression. | |
2423 | Like cxx_eval_unary_expression, except for trinary expressions. */ | |
2424 | ||
2425 | static tree | |
cf72f34d | 2426 | cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, |
f83e6885 | 2427 | bool addr, |
09b42213 | 2428 | bool *non_constant_p, bool *overflow_p) |
2429 | { | |
2430 | int i; | |
2431 | tree args[3]; | |
2432 | tree val; | |
2433 | ||
2434 | for (i = 0; i < 3; i++) | |
2435 | { | |
cf72f34d | 2436 | args[i] = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, i), |
f83e6885 | 2437 | addr, |
b2a43197 | 2438 | non_constant_p, overflow_p); |
09b42213 | 2439 | VERIFY_CONSTANT (args[i]); |
2440 | } | |
2441 | ||
2442 | val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t), | |
2443 | args[0], args[1], args[2]); | |
2444 | if (val == NULL_TREE) | |
2445 | return t; | |
2446 | VERIFY_CONSTANT (val); | |
2447 | return val; | |
2448 | } | |
2449 | ||
2450 | bool | |
2451 | var_in_constexpr_fn (tree t) | |
2452 | { | |
2453 | tree ctx = DECL_CONTEXT (t); | |
2454 | return (cxx_dialect >= cxx14 && ctx && TREE_CODE (ctx) == FUNCTION_DECL | |
2455 | && DECL_DECLARED_CONSTEXPR_P (ctx)); | |
2456 | } | |
2457 | ||
9c96033c | 2458 | /* Evaluate an INIT_EXPR or MODIFY_EXPR. */ |
2459 | ||
2460 | static tree | |
2461 | cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, | |
f83e6885 | 2462 | bool addr, |
9c96033c | 2463 | bool *non_constant_p, bool *overflow_p) |
2464 | { | |
2465 | constexpr_ctx new_ctx = *ctx; | |
2466 | ||
2467 | /* First we figure out where we're storing to. */ | |
2468 | tree target = TREE_OPERAND (t, 0); | |
2469 | target = cxx_eval_constant_expression (ctx, target, | |
f83e6885 | 2470 | true, |
b2a43197 | 2471 | non_constant_p, overflow_p); |
9c96033c | 2472 | if (*non_constant_p) |
2473 | return t; | |
2474 | ||
2475 | /* And then find the underlying variable. */ | |
2476 | vec<tree,va_gc> *refs = make_tree_vector(); | |
2477 | tree object = NULL_TREE; | |
2478 | for (tree probe = target; object == NULL_TREE; ) | |
2479 | { | |
2480 | switch (TREE_CODE (probe)) | |
2481 | { | |
2482 | case BIT_FIELD_REF: | |
2483 | case COMPONENT_REF: | |
2484 | case ARRAY_REF: | |
2485 | vec_safe_push (refs, TREE_OPERAND (probe, 1)); | |
2486 | vec_safe_push (refs, TREE_TYPE (probe)); | |
2487 | probe = TREE_OPERAND (probe, 0); | |
2488 | break; | |
2489 | ||
2490 | default: | |
2491 | object = probe; | |
2492 | gcc_assert (DECL_P (object)); | |
2493 | } | |
2494 | } | |
2495 | ||
2496 | /* And then find/build up our initializer for the path to the subobject | |
2497 | we're initializing. */ | |
2498 | tree *valp = ctx->values->get (object); | |
2499 | if (!valp) | |
2500 | { | |
2501 | /* A constant-expression cannot modify objects from outside the | |
2502 | constant-expression. */ | |
f83e6885 | 2503 | if (!ctx->quiet) |
9c96033c | 2504 | error ("modification of %qD is not a constant-expression", object); |
2505 | *non_constant_p = true; | |
2506 | return t; | |
2507 | } | |
2508 | tree type = TREE_TYPE (object); | |
2509 | while (!refs->is_empty()) | |
2510 | { | |
2511 | if (*valp == NULL_TREE) | |
2512 | { | |
2513 | *valp = build_constructor (type, NULL); | |
2514 | CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp) = true; | |
2515 | } | |
2516 | ||
2517 | constructor_elt ce; | |
2518 | type = refs->pop(); | |
2519 | ce.index = refs->pop(); | |
2520 | ce.value = NULL_TREE; | |
2521 | ||
2522 | unsigned HOST_WIDE_INT idx = 0; | |
2523 | constructor_elt *cep = NULL; | |
2524 | for (idx = 0; | |
2525 | vec_safe_iterate (CONSTRUCTOR_ELTS (*valp), idx, &cep); | |
2526 | idx++) | |
2527 | /* ??? slow */ | |
2528 | if (cp_tree_equal (ce.index, cep->index)) | |
2529 | break; | |
2530 | if (!cep) | |
2531 | cep = vec_safe_push (CONSTRUCTOR_ELTS (*valp), ce); | |
2532 | valp = &cep->value; | |
2533 | } | |
2534 | release_tree_vector (refs); | |
2535 | ||
2536 | if ((AGGREGATE_TYPE_P (TREE_TYPE (t)) || VECTOR_TYPE_P (TREE_TYPE (t)))) | |
2537 | { | |
2538 | /* Create a new CONSTRUCTOR in case evaluation of the initializer | |
2539 | wants to modify it. */ | |
2540 | *valp = new_ctx.ctor = build_constructor (TREE_TYPE (t), NULL); | |
2541 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
2542 | new_ctx.object = target; | |
2543 | } | |
2544 | ||
2545 | tree init = cxx_eval_constant_expression (&new_ctx, TREE_OPERAND (t, 1), | |
f83e6885 | 2546 | false, |
b2a43197 | 2547 | non_constant_p, overflow_p); |
9c96033c | 2548 | if (target == object) |
2549 | /* The hash table might have moved since the get earlier. */ | |
2550 | ctx->values->put (object, init); | |
2551 | else | |
2552 | *valp = init; | |
2553 | ||
2554 | if (*non_constant_p) | |
2555 | return t; | |
2556 | else if (addr) | |
2557 | return target; | |
2558 | else | |
dfac7dd2 | 2559 | return init; |
9c96033c | 2560 | } |
2561 | ||
2562 | /* Evaluate a ++ or -- expression. */ | |
2563 | ||
2564 | static tree | |
2565 | cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, | |
f83e6885 | 2566 | bool addr, |
9c96033c | 2567 | bool *non_constant_p, bool *overflow_p) |
2568 | { | |
2569 | enum tree_code code = TREE_CODE (t); | |
2570 | tree type = TREE_TYPE (t); | |
2571 | tree op = TREE_OPERAND (t, 0); | |
2572 | tree offset = TREE_OPERAND (t, 1); | |
2573 | gcc_assert (TREE_CONSTANT (offset)); | |
2574 | ||
2575 | /* The operand as an lvalue. */ | |
f83e6885 | 2576 | op = cxx_eval_constant_expression (ctx, op, true, |
b2a43197 | 2577 | non_constant_p, overflow_p); |
9c96033c | 2578 | |
2579 | /* The operand as an rvalue. */ | |
2580 | tree val = rvalue (op); | |
f83e6885 | 2581 | val = cxx_eval_constant_expression (ctx, val, false, |
b2a43197 | 2582 | non_constant_p, overflow_p); |
9c96033c | 2583 | VERIFY_CONSTANT (val); |
2584 | ||
2585 | /* The modified value. */ | |
2586 | bool inc = (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR); | |
c8a8f7ad | 2587 | tree mod; |
2588 | if (POINTER_TYPE_P (type)) | |
2589 | { | |
2590 | /* The middle end requires pointers to use POINTER_PLUS_EXPR. */ | |
2591 | offset = convert_to_ptrofftype (offset); | |
2592 | if (!inc) | |
2593 | offset = fold_build1 (NEGATE_EXPR, TREE_TYPE (offset), offset); | |
2594 | mod = fold_build2 (POINTER_PLUS_EXPR, type, val, offset); | |
2595 | } | |
2596 | else | |
2597 | mod = fold_build2 (inc ? PLUS_EXPR : MINUS_EXPR, type, val, offset); | |
9c96033c | 2598 | VERIFY_CONSTANT (mod); |
2599 | ||
2600 | /* Storing the modified value. */ | |
2601 | tree store = build2 (MODIFY_EXPR, type, op, mod); | |
f83e6885 | 2602 | cxx_eval_constant_expression (ctx, store, |
b2a43197 | 2603 | true, non_constant_p, overflow_p); |
9c96033c | 2604 | |
2605 | /* And the value of the expression. */ | |
2606 | if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) | |
2607 | { | |
2608 | /* Prefix ops are lvalues. */ | |
2609 | if (addr) | |
2610 | return op; | |
2611 | else | |
2612 | /* But we optimize when the caller wants an rvalue. */ | |
2613 | return mod; | |
2614 | } | |
2615 | else | |
2616 | /* Postfix ops are rvalues. */ | |
2617 | return val; | |
2618 | } | |
2619 | ||
00f21715 | 2620 | /* Predicates for the meaning of *jump_target. */ |
2621 | ||
2622 | static bool | |
2623 | returns (tree *jump_target) | |
2624 | { | |
2625 | return *jump_target | |
2626 | && TREE_CODE (*jump_target) == RETURN_EXPR; | |
2627 | } | |
2628 | ||
2629 | static bool | |
2630 | breaks (tree *jump_target) | |
2631 | { | |
2632 | return *jump_target | |
2633 | && TREE_CODE (*jump_target) == LABEL_DECL | |
2634 | && LABEL_DECL_BREAK (*jump_target); | |
2635 | } | |
2636 | ||
2637 | static bool | |
2638 | continues (tree *jump_target) | |
2639 | { | |
2640 | return *jump_target | |
2641 | && TREE_CODE (*jump_target) == LABEL_DECL | |
2642 | && LABEL_DECL_CONTINUE (*jump_target); | |
2643 | } | |
2644 | ||
2645 | static bool | |
2646 | switches (tree *jump_target) | |
2647 | { | |
2648 | return *jump_target | |
2649 | && TREE_CODE (*jump_target) == INTEGER_CST; | |
2650 | } | |
2651 | ||
2652 | /* Subroutine of cxx_eval_statement_list. Determine whether the statement | |
2653 | at I matches *jump_target. If we're looking for a case label and we see | |
2654 | the default label, copy I into DEFAULT_LABEL. */ | |
2655 | ||
2656 | static bool | |
2657 | label_matches (tree *jump_target, tree_stmt_iterator i, | |
2658 | tree_stmt_iterator& default_label) | |
2659 | { | |
2660 | tree stmt = tsi_stmt (i); | |
2661 | switch (TREE_CODE (*jump_target)) | |
2662 | { | |
2663 | case LABEL_DECL: | |
2664 | if (TREE_CODE (stmt) == LABEL_EXPR | |
2665 | && LABEL_EXPR_LABEL (stmt) == *jump_target) | |
2666 | return true; | |
2667 | break; | |
2668 | ||
2669 | case INTEGER_CST: | |
2670 | if (TREE_CODE (stmt) == CASE_LABEL_EXPR) | |
2671 | { | |
2672 | if (!CASE_LOW (stmt)) | |
2673 | default_label = i; | |
2674 | else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt))) | |
2675 | return true; | |
2676 | } | |
2677 | break; | |
2678 | ||
2679 | default: | |
2680 | gcc_unreachable (); | |
2681 | } | |
2682 | return false; | |
2683 | } | |
2684 | ||
2685 | /* Evaluate a STATEMENT_LIST for side-effects. Handles various jump | |
2686 | semantics, for switch, break, continue, and return. */ | |
2687 | ||
2688 | static tree | |
2689 | cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, | |
00f21715 | 2690 | bool *non_constant_p, bool *overflow_p, |
2691 | tree *jump_target) | |
2692 | { | |
2693 | tree_stmt_iterator i; | |
2694 | tree_stmt_iterator default_label = tree_stmt_iterator(); | |
da7981e0 | 2695 | tree local_target; |
2696 | /* In a statement-expression we want to return the last value. */ | |
2697 | tree r = NULL_TREE; | |
2698 | if (!jump_target) | |
2699 | { | |
2700 | local_target = NULL_TREE; | |
2701 | jump_target = &local_target; | |
2702 | } | |
00f21715 | 2703 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) |
2704 | { | |
2705 | reenter: | |
2706 | tree stmt = tsi_stmt (i); | |
2707 | if (*jump_target) | |
2708 | { | |
2709 | if (TREE_CODE (stmt) == STATEMENT_LIST) | |
2710 | /* The label we want might be inside. */; | |
2711 | else if (label_matches (jump_target, i, default_label)) | |
2712 | /* Found it. */ | |
2713 | *jump_target = NULL_TREE; | |
2714 | else | |
2715 | continue; | |
2716 | } | |
da7981e0 | 2717 | r = cxx_eval_constant_expression (ctx, stmt, false, |
2718 | non_constant_p, overflow_p, | |
2719 | jump_target); | |
00f21715 | 2720 | if (*non_constant_p) |
2721 | break; | |
2722 | if (returns (jump_target) || breaks (jump_target)) | |
2723 | break; | |
2724 | } | |
2725 | if (switches (jump_target) && !tsi_end_p (default_label)) | |
2726 | { | |
2727 | i = default_label; | |
2728 | *jump_target = NULL_TREE; | |
2729 | goto reenter; | |
2730 | } | |
da7981e0 | 2731 | return r; |
00f21715 | 2732 | } |
2733 | ||
2734 | /* Evaluate a LOOP_EXPR for side-effects. Handles break and return | |
2735 | semantics; continue semantics are covered by cxx_eval_statement_list. */ | |
2736 | ||
2737 | static tree | |
2738 | cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 2739 | bool *non_constant_p, bool *overflow_p, |
2740 | tree *jump_target) | |
2741 | { | |
2742 | tree body = TREE_OPERAND (t, 0); | |
2743 | while (true) | |
2744 | { | |
f83e6885 | 2745 | cxx_eval_statement_list (ctx, body, |
00f21715 | 2746 | non_constant_p, overflow_p, jump_target); |
2747 | if (returns (jump_target) || breaks (jump_target)) | |
2748 | break; | |
2749 | } | |
2750 | if (breaks (jump_target)) | |
2751 | *jump_target = NULL_TREE; | |
2752 | return NULL_TREE; | |
2753 | } | |
2754 | ||
2755 | /* Evaluate a SWITCH_EXPR for side-effects. Handles switch and break jump | |
2756 | semantics. */ | |
2757 | ||
2758 | static tree | |
2759 | cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 2760 | bool *non_constant_p, bool *overflow_p, |
2761 | tree *jump_target) | |
2762 | { | |
2763 | tree cond = TREE_OPERAND (t, 0); | |
f83e6885 | 2764 | cond = cxx_eval_constant_expression (ctx, cond, false, |
b2a43197 | 2765 | non_constant_p, overflow_p); |
00f21715 | 2766 | VERIFY_CONSTANT (cond); |
2767 | *jump_target = cond; | |
2768 | ||
2769 | tree body = TREE_OPERAND (t, 1); | |
f83e6885 | 2770 | cxx_eval_statement_list (ctx, body, |
00f21715 | 2771 | non_constant_p, overflow_p, jump_target); |
2772 | if (breaks (jump_target) || switches (jump_target)) | |
2773 | *jump_target = NULL_TREE; | |
2774 | return NULL_TREE; | |
2775 | } | |
2776 | ||
09b42213 | 2777 | /* Attempt to reduce the expression T to a constant value. |
2778 | On failure, issue diagnostic and return error_mark_node. */ | |
2779 | /* FIXME unify with c_fully_fold */ | |
9c96033c | 2780 | /* FIXME overflow_p is too global */ |
09b42213 | 2781 | |
2782 | static tree | |
cf72f34d | 2783 | cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, |
f83e6885 | 2784 | bool addr, |
00f21715 | 2785 | bool *non_constant_p, bool *overflow_p, |
2786 | tree *jump_target) | |
09b42213 | 2787 | { |
cf72f34d | 2788 | constexpr_ctx new_ctx; |
09b42213 | 2789 | tree r = t; |
2790 | ||
2791 | if (t == error_mark_node) | |
2792 | { | |
2793 | *non_constant_p = true; | |
2794 | return t; | |
2795 | } | |
2796 | if (CONSTANT_CLASS_P (t)) | |
2797 | { | |
2798 | if (TREE_CODE (t) == PTRMEM_CST) | |
2799 | t = cplus_expand_constant (t); | |
f83e6885 | 2800 | else if (TREE_OVERFLOW (t) && (!flag_permissive || ctx->quiet)) |
09b42213 | 2801 | *overflow_p = true; |
2802 | return t; | |
2803 | } | |
2804 | if (TREE_CODE (t) != NOP_EXPR | |
2805 | && reduced_constant_expression_p (t)) | |
2806 | return fold (t); | |
2807 | ||
2808 | switch (TREE_CODE (t)) | |
2809 | { | |
9c96033c | 2810 | case RESULT_DECL: |
2811 | if (addr) | |
2812 | return t; | |
2813 | /* We ask for an rvalue for the RESULT_DECL when indirecting | |
2814 | through an invisible reference. */ | |
2815 | gcc_assert (DECL_BY_REFERENCE (t)); | |
2816 | return (*ctx->values->get (t)); | |
2817 | ||
09b42213 | 2818 | case VAR_DECL: |
2819 | if (addr) | |
2820 | return t; | |
2821 | /* else fall through. */ | |
2822 | case CONST_DECL: | |
2055d27a | 2823 | if (ctx->strict) |
2824 | r = decl_really_constant_value (t); | |
2825 | else | |
2826 | r = decl_constant_value (t); | |
09b42213 | 2827 | if (TREE_CODE (r) == TARGET_EXPR |
2828 | && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR) | |
2829 | r = TARGET_EXPR_INITIAL (r); | |
cf72f34d | 2830 | if (TREE_CODE (r) == VAR_DECL) |
2831 | if (tree *p = ctx->values->get (r)) | |
2832 | r = *p; | |
09b42213 | 2833 | if (DECL_P (r)) |
2834 | { | |
f83e6885 | 2835 | if (!ctx->quiet) |
09b42213 | 2836 | non_const_var_error (r); |
2837 | *non_constant_p = true; | |
2838 | } | |
2839 | break; | |
2840 | ||
2841 | case FUNCTION_DECL: | |
2842 | case TEMPLATE_DECL: | |
2843 | case LABEL_DECL: | |
00f21715 | 2844 | case LABEL_EXPR: |
2845 | case CASE_LABEL_EXPR: | |
09b42213 | 2846 | return t; |
2847 | ||
2848 | case PARM_DECL: | |
9c96033c | 2849 | if (!use_new_call && ctx |
2850 | && ctx->call && DECL_CONTEXT (t) == ctx->call->fundef->decl) | |
cf72f34d | 2851 | r = lookup_parameter_binding (ctx->call, t); |
9c96033c | 2852 | else if (addr && TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE) |
2853 | /* glvalue use. */; | |
2854 | else if (tree *p = ctx->values->get (r)) | |
2855 | r = *p; | |
09b42213 | 2856 | else if (addr) |
2857 | /* Defer in case this is only used for its type. */; | |
1eb418cc | 2858 | else if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE) |
2859 | /* Defer, there's no lvalue->rvalue conversion. */; | |
a6613de7 | 2860 | else if (is_empty_class (TREE_TYPE (t))) |
2861 | { | |
2862 | /* If the class is empty, we aren't actually loading anything. */ | |
2863 | r = build_constructor (TREE_TYPE (t), NULL); | |
2864 | TREE_CONSTANT (r) = true; | |
2865 | } | |
09b42213 | 2866 | else |
2867 | { | |
f83e6885 | 2868 | if (!ctx->quiet) |
09b42213 | 2869 | error ("%qE is not a constant expression", t); |
2870 | *non_constant_p = true; | |
2871 | } | |
2872 | break; | |
2873 | ||
2874 | case CALL_EXPR: | |
2875 | case AGGR_INIT_EXPR: | |
f83e6885 | 2876 | r = cxx_eval_call_expression (ctx, t, addr, |
09b42213 | 2877 | non_constant_p, overflow_p); |
2878 | break; | |
2879 | ||
9c96033c | 2880 | case DECL_EXPR: |
2881 | { | |
2882 | r = DECL_EXPR_DECL (t); | |
2883 | if (AGGREGATE_TYPE_P (TREE_TYPE (r)) | |
2884 | || VECTOR_TYPE_P (TREE_TYPE (r))) | |
2885 | { | |
2886 | new_ctx = *ctx; | |
2887 | new_ctx.object = r; | |
2888 | new_ctx.ctor = build_constructor (TREE_TYPE (r), NULL); | |
2889 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
2890 | new_ctx.values->put (r, new_ctx.ctor); | |
2891 | ctx = &new_ctx; | |
2892 | } | |
2893 | ||
2894 | if (tree init = DECL_INITIAL (r)) | |
2895 | { | |
2896 | init = cxx_eval_constant_expression (ctx, init, | |
f83e6885 | 2897 | false, |
b2a43197 | 2898 | non_constant_p, overflow_p); |
9c96033c | 2899 | ctx->values->put (r, init); |
2900 | } | |
2901 | else if (ctx == &new_ctx) | |
2902 | /* We gave it a CONSTRUCTOR above. */; | |
2903 | else | |
2904 | ctx->values->put (r, NULL_TREE); | |
2905 | } | |
2906 | break; | |
2907 | ||
09b42213 | 2908 | case TARGET_EXPR: |
2909 | if (!literal_type_p (TREE_TYPE (t))) | |
2910 | { | |
f83e6885 | 2911 | if (!ctx->quiet) |
09b42213 | 2912 | { |
2913 | error ("temporary of non-literal type %qT in a " | |
2914 | "constant expression", TREE_TYPE (t)); | |
2915 | explain_non_literal_class (TREE_TYPE (t)); | |
2916 | } | |
2917 | *non_constant_p = true; | |
2918 | break; | |
2919 | } | |
cf72f34d | 2920 | if ((AGGREGATE_TYPE_P (TREE_TYPE (t)) || VECTOR_TYPE_P (TREE_TYPE (t)))) |
2921 | { | |
2922 | /* We're being expanded without an explicit target, so start | |
2923 | initializing a new object; expansion with an explicit target | |
2924 | strips the TARGET_EXPR before we get here. */ | |
2925 | new_ctx = *ctx; | |
2926 | new_ctx.ctor = build_constructor (TREE_TYPE (t), NULL); | |
2927 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
2928 | new_ctx.object = TARGET_EXPR_SLOT (t); | |
2929 | ctx->values->put (new_ctx.object, new_ctx.ctor); | |
2930 | ctx = &new_ctx; | |
2931 | } | |
9c96033c | 2932 | /* Pass false for 'addr' because this indicates |
09b42213 | 2933 | initialization of a temporary. */ |
cf72f34d | 2934 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 2935 | false, |
b2a43197 | 2936 | non_constant_p, overflow_p); |
09b42213 | 2937 | if (!*non_constant_p) |
2938 | /* Adjust the type of the result to the type of the temporary. */ | |
2939 | r = adjust_temp_type (TREE_TYPE (t), r); | |
1eb418cc | 2940 | if (addr) |
2941 | { | |
2942 | tree slot = TARGET_EXPR_SLOT (t); | |
2943 | ctx->values->put (slot, r); | |
2944 | return slot; | |
2945 | } | |
09b42213 | 2946 | break; |
2947 | ||
9c96033c | 2948 | case INIT_EXPR: |
2949 | if (!use_new_call) | |
2950 | { | |
2951 | /* In C++11 constexpr evaluation we are looking for the value, | |
2952 | not the side-effect of the initialization. */ | |
2953 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
f83e6885 | 2954 | false, |
b2a43197 | 2955 | non_constant_p, overflow_p); |
9c96033c | 2956 | break; |
2957 | } | |
2958 | /* else fall through */ | |
2959 | case MODIFY_EXPR: | |
f83e6885 | 2960 | r = cxx_eval_store_expression (ctx, t, addr, |
9c96033c | 2961 | non_constant_p, overflow_p); |
2962 | break; | |
2963 | ||
09b42213 | 2964 | case SCOPE_REF: |
cf72f34d | 2965 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 2966 | addr, |
b2a43197 | 2967 | non_constant_p, overflow_p); |
09b42213 | 2968 | break; |
2969 | ||
2970 | case RETURN_EXPR: | |
00f21715 | 2971 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
f83e6885 | 2972 | addr, |
b2a43197 | 2973 | non_constant_p, overflow_p); |
00f21715 | 2974 | *jump_target = t; |
2975 | break; | |
2976 | ||
e0e672a0 | 2977 | case SAVE_EXPR: |
2978 | /* Avoid evaluating a SAVE_EXPR more than once. */ | |
2979 | if (tree *p = ctx->values->get (t)) | |
2980 | r = *p; | |
2981 | else | |
2982 | { | |
2983 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), addr, | |
2984 | non_constant_p, overflow_p); | |
2985 | ctx->values->put (t, r); | |
2986 | } | |
2987 | break; | |
2988 | ||
09b42213 | 2989 | case NON_LVALUE_EXPR: |
2990 | case TRY_CATCH_EXPR: | |
2991 | case CLEANUP_POINT_EXPR: | |
2992 | case MUST_NOT_THROW_EXPR: | |
9c96033c | 2993 | case EXPR_STMT: |
2994 | case EH_SPEC_BLOCK: | |
cf72f34d | 2995 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
f83e6885 | 2996 | addr, |
00f21715 | 2997 | non_constant_p, overflow_p, |
2998 | jump_target); | |
09b42213 | 2999 | break; |
3000 | ||
3001 | /* These differ from cxx_eval_unary_expression in that this doesn't | |
3002 | check for a constant operand or result; an address can be | |
3003 | constant without its operand being, and vice versa. */ | |
3004 | case INDIRECT_REF: | |
f83e6885 | 3005 | r = cxx_eval_indirect_ref (ctx, t, addr, |
09b42213 | 3006 | non_constant_p, overflow_p); |
3007 | break; | |
3008 | ||
3009 | case ADDR_EXPR: | |
3010 | { | |
3011 | tree oldop = TREE_OPERAND (t, 0); | |
cf72f34d | 3012 | tree op = cxx_eval_constant_expression (ctx, oldop, |
09b42213 | 3013 | /*addr*/true, |
b2a43197 | 3014 | non_constant_p, overflow_p); |
09b42213 | 3015 | /* Don't VERIFY_CONSTANT here. */ |
3016 | if (*non_constant_p) | |
3017 | return t; | |
1eb418cc | 3018 | gcc_checking_assert (TREE_CODE (op) != CONSTRUCTOR); |
09b42213 | 3019 | /* This function does more aggressive folding than fold itself. */ |
3020 | r = build_fold_addr_expr_with_type (op, TREE_TYPE (t)); | |
3021 | if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop) | |
3022 | return t; | |
3023 | break; | |
3024 | } | |
3025 | ||
3026 | case REALPART_EXPR: | |
3027 | case IMAGPART_EXPR: | |
3028 | case CONJ_EXPR: | |
3029 | case FIX_TRUNC_EXPR: | |
3030 | case FLOAT_EXPR: | |
3031 | case NEGATE_EXPR: | |
3032 | case ABS_EXPR: | |
3033 | case BIT_NOT_EXPR: | |
3034 | case TRUTH_NOT_EXPR: | |
3035 | case FIXED_CONVERT_EXPR: | |
f83e6885 | 3036 | r = cxx_eval_unary_expression (ctx, t, addr, |
09b42213 | 3037 | non_constant_p, overflow_p); |
3038 | break; | |
3039 | ||
3040 | case SIZEOF_EXPR: | |
3041 | if (SIZEOF_EXPR_TYPE_P (t)) | |
3042 | r = cxx_sizeof_or_alignof_type (TREE_TYPE (TREE_OPERAND (t, 0)), | |
3043 | SIZEOF_EXPR, false); | |
3044 | else if (TYPE_P (TREE_OPERAND (t, 0))) | |
3045 | r = cxx_sizeof_or_alignof_type (TREE_OPERAND (t, 0), SIZEOF_EXPR, | |
3046 | false); | |
3047 | else | |
3048 | r = cxx_sizeof_or_alignof_expr (TREE_OPERAND (t, 0), SIZEOF_EXPR, | |
3049 | false); | |
3050 | if (r == error_mark_node) | |
3051 | r = size_one_node; | |
3052 | VERIFY_CONSTANT (r); | |
3053 | break; | |
3054 | ||
3055 | case COMPOUND_EXPR: | |
3056 | { | |
3057 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
3058 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
3059 | introduced by build_call_a. */ | |
3060 | tree op0 = TREE_OPERAND (t, 0); | |
3061 | tree op1 = TREE_OPERAND (t, 1); | |
3062 | STRIP_NOPS (op1); | |
3063 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
3064 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
f83e6885 | 3065 | r = cxx_eval_constant_expression (ctx, op0, |
00f21715 | 3066 | addr, non_constant_p, overflow_p, |
3067 | jump_target); | |
09b42213 | 3068 | else |
3069 | { | |
3070 | /* Check that the LHS is constant and then discard it. */ | |
f83e6885 | 3071 | cxx_eval_constant_expression (ctx, op0, |
00f21715 | 3072 | false, non_constant_p, overflow_p, |
3073 | jump_target); | |
09b42213 | 3074 | op1 = TREE_OPERAND (t, 1); |
f83e6885 | 3075 | r = cxx_eval_constant_expression (ctx, op1, |
00f21715 | 3076 | addr, non_constant_p, overflow_p, |
3077 | jump_target); | |
09b42213 | 3078 | } |
3079 | } | |
3080 | break; | |
3081 | ||
3082 | case POINTER_PLUS_EXPR: | |
3083 | case PLUS_EXPR: | |
3084 | case MINUS_EXPR: | |
3085 | case MULT_EXPR: | |
3086 | case TRUNC_DIV_EXPR: | |
3087 | case CEIL_DIV_EXPR: | |
3088 | case FLOOR_DIV_EXPR: | |
3089 | case ROUND_DIV_EXPR: | |
3090 | case TRUNC_MOD_EXPR: | |
3091 | case CEIL_MOD_EXPR: | |
3092 | case ROUND_MOD_EXPR: | |
3093 | case RDIV_EXPR: | |
3094 | case EXACT_DIV_EXPR: | |
3095 | case MIN_EXPR: | |
3096 | case MAX_EXPR: | |
3097 | case LSHIFT_EXPR: | |
3098 | case RSHIFT_EXPR: | |
3099 | case LROTATE_EXPR: | |
3100 | case RROTATE_EXPR: | |
3101 | case BIT_IOR_EXPR: | |
3102 | case BIT_XOR_EXPR: | |
3103 | case BIT_AND_EXPR: | |
3104 | case TRUTH_XOR_EXPR: | |
3105 | case LT_EXPR: | |
3106 | case LE_EXPR: | |
3107 | case GT_EXPR: | |
3108 | case GE_EXPR: | |
3109 | case EQ_EXPR: | |
3110 | case NE_EXPR: | |
3111 | case UNORDERED_EXPR: | |
3112 | case ORDERED_EXPR: | |
3113 | case UNLT_EXPR: | |
3114 | case UNLE_EXPR: | |
3115 | case UNGT_EXPR: | |
3116 | case UNGE_EXPR: | |
3117 | case UNEQ_EXPR: | |
3118 | case LTGT_EXPR: | |
3119 | case RANGE_EXPR: | |
3120 | case COMPLEX_EXPR: | |
f83e6885 | 3121 | r = cxx_eval_binary_expression (ctx, t, addr, |
09b42213 | 3122 | non_constant_p, overflow_p); |
3123 | break; | |
3124 | ||
3125 | /* fold can introduce non-IF versions of these; still treat them as | |
3126 | short-circuiting. */ | |
3127 | case TRUTH_AND_EXPR: | |
3128 | case TRUTH_ANDIF_EXPR: | |
cf72f34d | 3129 | r = cxx_eval_logical_expression (ctx, t, boolean_false_node, |
09b42213 | 3130 | boolean_true_node, |
f83e6885 | 3131 | addr, |
09b42213 | 3132 | non_constant_p, overflow_p); |
3133 | break; | |
3134 | ||
3135 | case TRUTH_OR_EXPR: | |
3136 | case TRUTH_ORIF_EXPR: | |
cf72f34d | 3137 | r = cxx_eval_logical_expression (ctx, t, boolean_true_node, |
09b42213 | 3138 | boolean_false_node, |
f83e6885 | 3139 | addr, |
09b42213 | 3140 | non_constant_p, overflow_p); |
3141 | break; | |
3142 | ||
3143 | case ARRAY_REF: | |
f83e6885 | 3144 | r = cxx_eval_array_reference (ctx, t, addr, |
09b42213 | 3145 | non_constant_p, overflow_p); |
3146 | break; | |
3147 | ||
3148 | case COMPONENT_REF: | |
3149 | if (is_overloaded_fn (t)) | |
3150 | { | |
3151 | /* We can only get here in checking mode via | |
3152 | build_non_dependent_expr, because any expression that | |
3153 | calls or takes the address of the function will have | |
3154 | pulled a FUNCTION_DECL out of the COMPONENT_REF. */ | |
f83e6885 | 3155 | gcc_checking_assert (ctx->quiet || errorcount); |
09b42213 | 3156 | *non_constant_p = true; |
3157 | return t; | |
3158 | } | |
f83e6885 | 3159 | r = cxx_eval_component_reference (ctx, t, addr, |
09b42213 | 3160 | non_constant_p, overflow_p); |
3161 | break; | |
3162 | ||
3163 | case BIT_FIELD_REF: | |
f83e6885 | 3164 | r = cxx_eval_bit_field_ref (ctx, t, addr, |
09b42213 | 3165 | non_constant_p, overflow_p); |
3166 | break; | |
3167 | ||
3168 | case COND_EXPR: | |
3169 | case VEC_COND_EXPR: | |
f83e6885 | 3170 | r = cxx_eval_conditional_expression (ctx, t, addr, |
00f21715 | 3171 | non_constant_p, overflow_p, |
3172 | jump_target); | |
09b42213 | 3173 | break; |
3174 | ||
3175 | case CONSTRUCTOR: | |
f83e6885 | 3176 | r = cxx_eval_bare_aggregate (ctx, t, addr, |
09b42213 | 3177 | non_constant_p, overflow_p); |
3178 | break; | |
3179 | ||
3180 | case VEC_INIT_EXPR: | |
3181 | /* We can get this in a defaulted constructor for a class with a | |
3182 | non-static data member of array type. Either the initializer will | |
3183 | be NULL, meaning default-initialization, or it will be an lvalue | |
3184 | or xvalue of the same type, meaning direct-initialization from the | |
3185 | corresponding member. */ | |
f83e6885 | 3186 | r = cxx_eval_vec_init (ctx, t, addr, |
09b42213 | 3187 | non_constant_p, overflow_p); |
3188 | break; | |
3189 | ||
3190 | case FMA_EXPR: | |
3191 | case VEC_PERM_EXPR: | |
f83e6885 | 3192 | r = cxx_eval_trinary_expression (ctx, t, addr, |
09b42213 | 3193 | non_constant_p, overflow_p); |
3194 | break; | |
3195 | ||
3196 | case CONVERT_EXPR: | |
3197 | case VIEW_CONVERT_EXPR: | |
3198 | case NOP_EXPR: | |
3199 | { | |
3200 | tree oldop = TREE_OPERAND (t, 0); | |
cf72f34d | 3201 | tree op = cxx_eval_constant_expression (ctx, oldop, |
f83e6885 | 3202 | addr, |
b2a43197 | 3203 | non_constant_p, overflow_p); |
09b42213 | 3204 | if (*non_constant_p) |
3205 | return t; | |
3206 | if (POINTER_TYPE_P (TREE_TYPE (t)) | |
3207 | && TREE_CODE (op) == INTEGER_CST | |
3208 | && !integer_zerop (op)) | |
3209 | { | |
f83e6885 | 3210 | if (!ctx->quiet) |
09b42213 | 3211 | error_at (EXPR_LOC_OR_LOC (t, input_location), |
3212 | "reinterpret_cast from integer to pointer"); | |
3213 | *non_constant_p = true; | |
3214 | return t; | |
3215 | } | |
3216 | if (op == oldop) | |
3217 | /* We didn't fold at the top so we could check for ptr-int | |
3218 | conversion. */ | |
3219 | return fold (t); | |
3220 | r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), op); | |
3221 | /* Conversion of an out-of-range value has implementation-defined | |
3222 | behavior; the language considers it different from arithmetic | |
3223 | overflow, which is undefined. */ | |
3224 | if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op)) | |
3225 | TREE_OVERFLOW (r) = false; | |
3226 | } | |
3227 | break; | |
3228 | ||
3229 | case EMPTY_CLASS_EXPR: | |
3230 | /* This is good enough for a function argument that might not get | |
3231 | used, and they can't do anything with it, so just return it. */ | |
3232 | return t; | |
3233 | ||
9c96033c | 3234 | case STATEMENT_LIST: |
00f21715 | 3235 | new_ctx = *ctx; |
3236 | new_ctx.ctor = new_ctx.object = NULL_TREE; | |
f83e6885 | 3237 | return cxx_eval_statement_list (&new_ctx, t, |
00f21715 | 3238 | non_constant_p, overflow_p, jump_target); |
9c96033c | 3239 | |
3240 | case BIND_EXPR: | |
3241 | return cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t), | |
f83e6885 | 3242 | addr, |
00f21715 | 3243 | non_constant_p, overflow_p, |
3244 | jump_target); | |
9c96033c | 3245 | |
09b42213 | 3246 | case PREINCREMENT_EXPR: |
3247 | case POSTINCREMENT_EXPR: | |
3248 | case PREDECREMENT_EXPR: | |
3249 | case POSTDECREMENT_EXPR: | |
f83e6885 | 3250 | return cxx_eval_increment_expression (ctx, t, |
9c96033c | 3251 | addr, non_constant_p, overflow_p); |
3252 | ||
3253 | case LAMBDA_EXPR: | |
09b42213 | 3254 | case NEW_EXPR: |
3255 | case VEC_NEW_EXPR: | |
3256 | case DELETE_EXPR: | |
3257 | case VEC_DELETE_EXPR: | |
3258 | case THROW_EXPR: | |
09b42213 | 3259 | case MODOP_EXPR: |
3260 | /* GCC internal stuff. */ | |
3261 | case VA_ARG_EXPR: | |
3262 | case OBJ_TYPE_REF: | |
3263 | case WITH_CLEANUP_EXPR: | |
09b42213 | 3264 | case NON_DEPENDENT_EXPR: |
3265 | case BASELINK: | |
09b42213 | 3266 | case OFFSET_REF: |
f83e6885 | 3267 | if (!ctx->quiet) |
09b42213 | 3268 | error_at (EXPR_LOC_OR_LOC (t, input_location), |
3269 | "expression %qE is not a constant-expression", t); | |
3270 | *non_constant_p = true; | |
3271 | break; | |
3272 | ||
cf72f34d | 3273 | case PLACEHOLDER_EXPR: |
3274 | if (!ctx || !ctx->ctor || (addr && !ctx->object)) | |
3275 | { | |
3276 | /* A placeholder without a referent. We can get here when | |
3277 | checking whether NSDMIs are noexcept, or in massage_init_elt; | |
3278 | just say it's non-constant for now. */ | |
f83e6885 | 3279 | gcc_assert (ctx->quiet); |
cf72f34d | 3280 | *non_constant_p = true; |
3281 | break; | |
3282 | } | |
3283 | else | |
3284 | { | |
3285 | /* Use of the value or address of the current object. We could | |
3286 | use ctx->object unconditionally, but using ctx->ctor when we | |
3287 | can is a minor optimization. */ | |
3288 | tree ctor = addr ? ctx->object : ctx->ctor; | |
3289 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
3290 | (TREE_TYPE (t), TREE_TYPE (ctor))); | |
3291 | return cxx_eval_constant_expression | |
f83e6885 | 3292 | (ctx, ctor, addr, |
b2a43197 | 3293 | non_constant_p, overflow_p); |
cf72f34d | 3294 | } |
3295 | break; | |
3296 | ||
9c96033c | 3297 | case GOTO_EXPR: |
00f21715 | 3298 | *jump_target = TREE_OPERAND (t, 0); |
3299 | gcc_assert (breaks (jump_target) || continues (jump_target)); | |
3300 | break; | |
3301 | ||
9c96033c | 3302 | case LOOP_EXPR: |
f83e6885 | 3303 | cxx_eval_loop_expr (ctx, t, |
00f21715 | 3304 | non_constant_p, overflow_p, jump_target); |
3305 | break; | |
3306 | ||
9c96033c | 3307 | case SWITCH_EXPR: |
f83e6885 | 3308 | cxx_eval_switch_expr (ctx, t, |
00f21715 | 3309 | non_constant_p, overflow_p, jump_target); |
9c96033c | 3310 | break; |
3311 | ||
09b42213 | 3312 | default: |
3313 | internal_error ("unexpected expression %qE of kind %s", t, | |
3314 | get_tree_code_name (TREE_CODE (t))); | |
3315 | *non_constant_p = true; | |
3316 | break; | |
3317 | } | |
3318 | ||
3319 | if (r == error_mark_node) | |
3320 | *non_constant_p = true; | |
3321 | ||
3322 | if (*non_constant_p) | |
3323 | return t; | |
3324 | else | |
3325 | return r; | |
3326 | } | |
3327 | ||
3328 | static tree | |
cf72f34d | 3329 | cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, |
2055d27a | 3330 | bool strict = true, tree object = NULL_TREE) |
09b42213 | 3331 | { |
3332 | bool non_constant_p = false; | |
3333 | bool overflow_p = false; | |
2055d27a | 3334 | constexpr_ctx ctx = { NULL, NULL, NULL, NULL, allow_non_constant, strict }; |
cf72f34d | 3335 | hash_map<tree,tree> map; |
3336 | ctx.values = ↦ | |
3337 | tree type = initialized_type (t); | |
cf72f34d | 3338 | tree r = t; |
3339 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) | |
3340 | { | |
3341 | /* In C++14 an NSDMI can participate in aggregate initialization, | |
3342 | and can refer to the address of the object being initialized, so | |
3343 | we need to pass in the relevant VAR_DECL if we want to do the | |
3344 | evaluation in a single pass. The evaluation will dynamically | |
3345 | update ctx.values for the VAR_DECL. We use the same strategy | |
3346 | for C++11 constexpr constructors that refer to the object being | |
3347 | initialized. */ | |
3348 | ctx.ctor = build_constructor (type, NULL); | |
3349 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctx.ctor) = true; | |
9c96033c | 3350 | if (!object) |
3351 | { | |
3352 | if (TREE_CODE (t) == TARGET_EXPR) | |
3353 | object = TARGET_EXPR_SLOT (t); | |
3354 | else if (TREE_CODE (t) == AGGR_INIT_EXPR) | |
3355 | object = AGGR_INIT_EXPR_SLOT (t); | |
3356 | } | |
cf72f34d | 3357 | ctx.object = object; |
3358 | if (object) | |
3359 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
3360 | (type, TREE_TYPE (object))); | |
3361 | if (object && DECL_P (object)) | |
3362 | map.put (object, ctx.ctor); | |
3363 | if (TREE_CODE (r) == TARGET_EXPR) | |
3364 | /* Avoid creating another CONSTRUCTOR when we expand the | |
3365 | TARGET_EXPR. */ | |
3366 | r = TARGET_EXPR_INITIAL (r); | |
3367 | } | |
3368 | ||
f83e6885 | 3369 | r = cxx_eval_constant_expression (&ctx, r, |
b2a43197 | 3370 | false, &non_constant_p, &overflow_p); |
09b42213 | 3371 | |
3372 | verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); | |
3373 | ||
bbcc9042 | 3374 | /* Mutable logic is a bit tricky: we want to allow initialization of |
3375 | constexpr variables with mutable members, but we can't copy those | |
3376 | members to another constexpr variable. */ | |
3377 | if (TREE_CODE (r) == CONSTRUCTOR | |
3378 | && CONSTRUCTOR_MUTABLE_POISON (r)) | |
09b42213 | 3379 | { |
09b42213 | 3380 | if (!allow_non_constant) |
bbcc9042 | 3381 | error ("%qE is not a constant expression because it refers to " |
3382 | "mutable subobjects of %qT", t, type); | |
09b42213 | 3383 | non_constant_p = true; |
3384 | } | |
3385 | ||
3386 | /* Technically we should check this for all subexpressions, but that | |
3387 | runs into problems with our internal representation of pointer | |
3388 | subtraction and the 5.19 rules are still in flux. */ | |
3389 | if (CONVERT_EXPR_CODE_P (TREE_CODE (r)) | |
3390 | && ARITHMETIC_TYPE_P (TREE_TYPE (r)) | |
3391 | && TREE_CODE (TREE_OPERAND (r, 0)) == ADDR_EXPR) | |
3392 | { | |
3393 | if (!allow_non_constant) | |
3394 | error ("conversion from pointer type %qT " | |
3395 | "to arithmetic type %qT in a constant-expression", | |
3396 | TREE_TYPE (TREE_OPERAND (r, 0)), TREE_TYPE (r)); | |
3397 | non_constant_p = true; | |
3398 | } | |
3399 | ||
3400 | if (!non_constant_p && overflow_p) | |
3401 | non_constant_p = true; | |
3402 | ||
3403 | if (non_constant_p && !allow_non_constant) | |
3404 | return error_mark_node; | |
3405 | else if (non_constant_p && TREE_CONSTANT (r)) | |
3406 | { | |
3407 | /* This isn't actually constant, so unset TREE_CONSTANT. */ | |
3408 | if (EXPR_P (r)) | |
3409 | r = copy_node (r); | |
3410 | else if (TREE_CODE (r) == CONSTRUCTOR) | |
3411 | r = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (r), r); | |
3412 | else | |
3413 | r = build_nop (TREE_TYPE (r), r); | |
3414 | TREE_CONSTANT (r) = false; | |
3415 | } | |
3416 | else if (non_constant_p || r == t) | |
3417 | return t; | |
3418 | ||
3419 | if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r))) | |
3420 | { | |
3421 | if (TREE_CODE (t) == TARGET_EXPR | |
3422 | && TARGET_EXPR_INITIAL (t) == r) | |
3423 | return t; | |
3424 | else | |
3425 | { | |
3426 | r = get_target_expr (r); | |
3427 | TREE_CONSTANT (r) = true; | |
3428 | return r; | |
3429 | } | |
3430 | } | |
3431 | else | |
3432 | return r; | |
3433 | } | |
3434 | ||
3435 | /* Returns true if T is a valid subexpression of a constant expression, | |
3436 | even if it isn't itself a constant expression. */ | |
3437 | ||
3438 | bool | |
3439 | is_sub_constant_expr (tree t) | |
3440 | { | |
3441 | bool non_constant_p = false; | |
3442 | bool overflow_p = false; | |
2055d27a | 3443 | constexpr_ctx ctx = { NULL, NULL, NULL, NULL, true, true }; |
cf72f34d | 3444 | hash_map <tree, tree> map; |
3445 | ctx.values = ↦ | |
f83e6885 | 3446 | cxx_eval_constant_expression (&ctx, t, false, &non_constant_p, |
b2a43197 | 3447 | &overflow_p); |
09b42213 | 3448 | return !non_constant_p && !overflow_p; |
3449 | } | |
3450 | ||
3451 | /* If T represents a constant expression returns its reduced value. | |
3452 | Otherwise return error_mark_node. If T is dependent, then | |
3453 | return NULL. */ | |
3454 | ||
3455 | tree | |
cf72f34d | 3456 | cxx_constant_value (tree t, tree decl) |
09b42213 | 3457 | { |
2055d27a | 3458 | return cxx_eval_outermost_constant_expr (t, false, true, decl); |
09b42213 | 3459 | } |
3460 | ||
3461 | /* If T is a constant expression, returns its reduced value. | |
3462 | Otherwise, if T does not have TREE_CONSTANT set, returns T. | |
3463 | Otherwise, returns a version of T without TREE_CONSTANT. */ | |
3464 | ||
3465 | tree | |
cf72f34d | 3466 | maybe_constant_value (tree t, tree decl) |
09b42213 | 3467 | { |
3468 | tree r; | |
3469 | ||
3470 | if (instantiation_dependent_expression_p (t) | |
3471 | || type_unknown_p (t) | |
3472 | || BRACE_ENCLOSED_INITIALIZER_P (t) | |
3473 | || !potential_constant_expression (t)) | |
3474 | { | |
3475 | if (TREE_OVERFLOW_P (t)) | |
3476 | { | |
3477 | t = build_nop (TREE_TYPE (t), t); | |
3478 | TREE_CONSTANT (t) = false; | |
3479 | } | |
3480 | return t; | |
3481 | } | |
3482 | ||
2055d27a | 3483 | r = cxx_eval_outermost_constant_expr (t, true, true, decl); |
09b42213 | 3484 | #ifdef ENABLE_CHECKING |
3485 | /* cp_tree_equal looks through NOPs, so allow them. */ | |
3486 | gcc_assert (r == t | |
3487 | || CONVERT_EXPR_P (t) | |
21131a05 | 3488 | || TREE_CODE (t) == VIEW_CONVERT_EXPR |
09b42213 | 3489 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) |
3490 | || !cp_tree_equal (r, t)); | |
3491 | #endif | |
3492 | return r; | |
3493 | } | |
3494 | ||
21131a05 | 3495 | /* Like maybe_constant_value but first fully instantiate the argument. |
3496 | ||
3497 | Note: this is equivalent to instantiate_non_dependent_expr_sfinae | |
3498 | (t, tf_none) followed by maybe_constant_value but is more efficient, | |
3499 | because calls instantiation_dependent_expression_p and | |
3500 | potential_constant_expression at most once. */ | |
3501 | ||
3502 | tree | |
3503 | fold_non_dependent_expr (tree t) | |
3504 | { | |
3505 | if (t == NULL_TREE) | |
3506 | return NULL_TREE; | |
3507 | ||
3508 | /* If we're in a template, but T isn't value dependent, simplify | |
3509 | it. We're supposed to treat: | |
3510 | ||
3511 | template <typename T> void f(T[1 + 1]); | |
3512 | template <typename T> void f(T[2]); | |
3513 | ||
3514 | as two declarations of the same function, for example. */ | |
3515 | if (processing_template_decl) | |
3516 | { | |
3517 | if (!instantiation_dependent_expression_p (t) | |
3518 | && potential_constant_expression (t)) | |
3519 | { | |
c8a9f04c | 3520 | processing_template_decl_sentinel s; |
3521 | t = instantiate_non_dependent_expr_internal (t, tf_none); | |
21131a05 | 3522 | |
3523 | if (type_unknown_p (t) | |
3524 | || BRACE_ENCLOSED_INITIALIZER_P (t)) | |
3525 | { | |
3526 | if (TREE_OVERFLOW_P (t)) | |
3527 | { | |
3528 | t = build_nop (TREE_TYPE (t), t); | |
3529 | TREE_CONSTANT (t) = false; | |
3530 | } | |
3531 | return t; | |
3532 | } | |
3533 | ||
2055d27a | 3534 | tree r = cxx_eval_outermost_constant_expr (t, true, true, NULL_TREE); |
21131a05 | 3535 | #ifdef ENABLE_CHECKING |
3536 | /* cp_tree_equal looks through NOPs, so allow them. */ | |
3537 | gcc_assert (r == t | |
3538 | || CONVERT_EXPR_P (t) | |
3539 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
3540 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
3541 | || !cp_tree_equal (r, t)); | |
3542 | #endif | |
3543 | return r; | |
3544 | } | |
3545 | else if (TREE_OVERFLOW_P (t)) | |
3546 | { | |
3547 | t = build_nop (TREE_TYPE (t), t); | |
3548 | TREE_CONSTANT (t) = false; | |
3549 | } | |
3550 | return t; | |
3551 | } | |
3552 | ||
3553 | return maybe_constant_value (t); | |
3554 | } | |
3555 | ||
09b42213 | 3556 | /* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather |
3557 | than wrapped in a TARGET_EXPR. */ | |
3558 | ||
3559 | tree | |
cf72f34d | 3560 | maybe_constant_init (tree t, tree decl) |
09b42213 | 3561 | { |
3562 | if (TREE_CODE (t) == EXPR_STMT) | |
3563 | t = TREE_OPERAND (t, 0); | |
3564 | if (TREE_CODE (t) == CONVERT_EXPR | |
3565 | && VOID_TYPE_P (TREE_TYPE (t))) | |
3566 | t = TREE_OPERAND (t, 0); | |
9c96033c | 3567 | if (TREE_CODE (t) == INIT_EXPR) |
3568 | t = TREE_OPERAND (t, 1); | |
2055d27a | 3569 | if (instantiation_dependent_expression_p (t) |
3570 | || type_unknown_p (t) | |
3571 | || BRACE_ENCLOSED_INITIALIZER_P (t) | |
3572 | || !potential_static_init_expression (t)) | |
3573 | /* Don't try to evaluate it. */; | |
3574 | else | |
3575 | t = cxx_eval_outermost_constant_expr (t, true, false, decl); | |
09b42213 | 3576 | if (TREE_CODE (t) == TARGET_EXPR) |
3577 | { | |
3578 | tree init = TARGET_EXPR_INITIAL (t); | |
3579 | if (TREE_CODE (init) == CONSTRUCTOR) | |
3580 | t = init; | |
3581 | } | |
3582 | return t; | |
3583 | } | |
3584 | ||
3585 | #if 0 | |
3586 | /* FIXME see ADDR_EXPR section in potential_constant_expression_1. */ | |
3587 | /* Return true if the object referred to by REF has automatic or thread | |
3588 | local storage. */ | |
3589 | ||
3590 | enum { ck_ok, ck_bad, ck_unknown }; | |
3591 | static int | |
3592 | check_automatic_or_tls (tree ref) | |
3593 | { | |
3754d046 | 3594 | machine_mode mode; |
09b42213 | 3595 | HOST_WIDE_INT bitsize, bitpos; |
3596 | tree offset; | |
3597 | int volatilep = 0, unsignedp = 0; | |
3598 | tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset, | |
3599 | &mode, &unsignedp, &volatilep, false); | |
3600 | duration_kind dk; | |
3601 | ||
3602 | /* If there isn't a decl in the middle, we don't know the linkage here, | |
3603 | and this isn't a constant expression anyway. */ | |
3604 | if (!DECL_P (decl)) | |
3605 | return ck_unknown; | |
3606 | dk = decl_storage_duration (decl); | |
3607 | return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok; | |
3608 | } | |
3609 | #endif | |
3610 | ||
3611 | /* Return true if T denotes a potentially constant expression. Issue | |
3612 | diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true, | |
3613 | an lvalue-rvalue conversion is implied. | |
3614 | ||
3615 | C++0x [expr.const] used to say | |
3616 | ||
3617 | 6 An expression is a potential constant expression if it is | |
3618 | a constant expression where all occurrences of function | |
3619 | parameters are replaced by arbitrary constant expressions | |
3620 | of the appropriate type. | |
3621 | ||
3622 | 2 A conditional expression is a constant expression unless it | |
3623 | involves one of the following as a potentially evaluated | |
3624 | subexpression (3.2), but subexpressions of logical AND (5.14), | |
3625 | logical OR (5.15), and conditional (5.16) operations that are | |
3626 | not evaluated are not considered. */ | |
3627 | ||
3628 | static bool | |
2055d27a | 3629 | potential_constant_expression_1 (tree t, bool want_rval, bool strict, |
3630 | tsubst_flags_t flags) | |
09b42213 | 3631 | { |
2055d27a | 3632 | #define RECUR(T,RV) potential_constant_expression_1 ((T), (RV), strict, flags) |
09b42213 | 3633 | enum { any = false, rval = true }; |
3634 | int i; | |
3635 | tree tmp; | |
3636 | ||
3637 | if (t == error_mark_node) | |
3638 | return false; | |
3639 | if (t == NULL_TREE) | |
3640 | return true; | |
3641 | if (TREE_THIS_VOLATILE (t)) | |
3642 | { | |
3643 | if (flags & tf_error) | |
3644 | error ("expression %qE has side-effects", t); | |
3645 | return false; | |
3646 | } | |
3647 | if (CONSTANT_CLASS_P (t)) | |
3648 | return true; | |
3649 | ||
3650 | switch (TREE_CODE (t)) | |
3651 | { | |
3652 | case FUNCTION_DECL: | |
3653 | case BASELINK: | |
3654 | case TEMPLATE_DECL: | |
3655 | case OVERLOAD: | |
3656 | case TEMPLATE_ID_EXPR: | |
3657 | case LABEL_DECL: | |
3658 | case LABEL_EXPR: | |
9c96033c | 3659 | case CASE_LABEL_EXPR: |
09b42213 | 3660 | case CONST_DECL: |
3661 | case SIZEOF_EXPR: | |
3662 | case ALIGNOF_EXPR: | |
3663 | case OFFSETOF_EXPR: | |
3664 | case NOEXCEPT_EXPR: | |
3665 | case TEMPLATE_PARM_INDEX: | |
3666 | case TRAIT_EXPR: | |
3667 | case IDENTIFIER_NODE: | |
3668 | case USERDEF_LITERAL: | |
3669 | /* We can see a FIELD_DECL in a pointer-to-member expression. */ | |
3670 | case FIELD_DECL: | |
3671 | case PARM_DECL: | |
3672 | case USING_DECL: | |
9c96033c | 3673 | case USING_STMT: |
cf72f34d | 3674 | case PLACEHOLDER_EXPR: |
9c96033c | 3675 | case BREAK_STMT: |
3676 | case CONTINUE_STMT: | |
09b42213 | 3677 | return true; |
3678 | ||
3679 | case AGGR_INIT_EXPR: | |
3680 | case CALL_EXPR: | |
3681 | /* -- an invocation of a function other than a constexpr function | |
3682 | or a constexpr constructor. */ | |
3683 | { | |
3684 | tree fun = get_function_named_in_call (t); | |
3685 | const int nargs = call_expr_nargs (t); | |
3686 | i = 0; | |
3687 | ||
9c96033c | 3688 | if (fun == NULL_TREE) |
3689 | { | |
3690 | /* fold_call_expr can't do anything with IFN calls. */ | |
3691 | if (flags & tf_error) | |
3692 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
3693 | "call to internal function"); | |
3694 | return false; | |
3695 | } | |
09b42213 | 3696 | if (is_overloaded_fn (fun)) |
3697 | { | |
3698 | if (TREE_CODE (fun) == FUNCTION_DECL) | |
3699 | { | |
3700 | if (builtin_valid_in_constant_expr_p (fun)) | |
3701 | return true; | |
3702 | if (!DECL_DECLARED_CONSTEXPR_P (fun) | |
3703 | /* Allow any built-in function; if the expansion | |
3704 | isn't constant, we'll deal with that then. */ | |
3705 | && !is_builtin_fn (fun)) | |
3706 | { | |
3707 | if (flags & tf_error) | |
3708 | { | |
3709 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
3710 | "call to non-constexpr function %qD", fun); | |
3711 | explain_invalid_constexpr_fn (fun); | |
3712 | } | |
3713 | return false; | |
3714 | } | |
3715 | /* A call to a non-static member function takes the address | |
3716 | of the object as the first argument. But in a constant | |
3717 | expression the address will be folded away, so look | |
3718 | through it now. */ | |
3719 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
3720 | && !DECL_CONSTRUCTOR_P (fun)) | |
3721 | { | |
3722 | tree x = get_nth_callarg (t, 0); | |
3723 | if (is_this_parameter (x)) | |
cf72f34d | 3724 | return true; |
2055d27a | 3725 | else if (!RECUR (x, rval)) |
09b42213 | 3726 | return false; |
3727 | i = 1; | |
3728 | } | |
3729 | } | |
3730 | else | |
3731 | { | |
2055d27a | 3732 | if (!RECUR (fun, true)) |
09b42213 | 3733 | return false; |
3734 | fun = get_first_fn (fun); | |
3735 | } | |
3736 | /* Skip initial arguments to base constructors. */ | |
3737 | if (DECL_BASE_CONSTRUCTOR_P (fun)) | |
3738 | i = num_artificial_parms_for (fun); | |
3739 | fun = DECL_ORIGIN (fun); | |
3740 | } | |
3741 | else | |
3742 | { | |
2055d27a | 3743 | if (RECUR (fun, rval)) |
09b42213 | 3744 | /* Might end up being a constant function pointer. */; |
3745 | else | |
3746 | return false; | |
3747 | } | |
3748 | for (; i < nargs; ++i) | |
3749 | { | |
3750 | tree x = get_nth_callarg (t, i); | |
2055d27a | 3751 | if (!RECUR (x, rval)) |
09b42213 | 3752 | return false; |
3753 | } | |
3754 | return true; | |
3755 | } | |
3756 | ||
3757 | case NON_LVALUE_EXPR: | |
3758 | /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to | |
3759 | -- an lvalue of integral type that refers to a non-volatile | |
3760 | const variable or static data member initialized with | |
3761 | constant expressions, or | |
3762 | ||
3763 | -- an lvalue of literal type that refers to non-volatile | |
3764 | object defined with constexpr, or that refers to a | |
3765 | sub-object of such an object; */ | |
2055d27a | 3766 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 3767 | |
3768 | case VAR_DECL: | |
2055d27a | 3769 | if (want_rval |
3770 | && !decl_constant_var_p (t) | |
3771 | && (strict | |
3772 | || !CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (t)) | |
3773 | || !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (t)) | |
09b42213 | 3774 | && !var_in_constexpr_fn (t) |
3775 | && !dependent_type_p (TREE_TYPE (t))) | |
3776 | { | |
3777 | if (flags & tf_error) | |
3778 | non_const_var_error (t); | |
3779 | return false; | |
3780 | } | |
3781 | return true; | |
3782 | ||
3783 | case NOP_EXPR: | |
3784 | case CONVERT_EXPR: | |
3785 | case VIEW_CONVERT_EXPR: | |
3786 | /* -- a reinterpret_cast. FIXME not implemented, and this rule | |
3787 | may change to something more specific to type-punning (DR 1312). */ | |
3788 | { | |
3789 | tree from = TREE_OPERAND (t, 0); | |
3790 | if (POINTER_TYPE_P (TREE_TYPE (t)) | |
3791 | && TREE_CODE (from) == INTEGER_CST | |
3792 | && !integer_zerop (from)) | |
3793 | { | |
3794 | if (flags & tf_error) | |
3795 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
3796 | "reinterpret_cast from integer to pointer"); | |
3797 | return false; | |
3798 | } | |
2055d27a | 3799 | return (RECUR (from, TREE_CODE (t) != VIEW_CONVERT_EXPR)); |
09b42213 | 3800 | } |
3801 | ||
3802 | case ADDR_EXPR: | |
3803 | /* -- a unary operator & that is applied to an lvalue that | |
3804 | designates an object with thread or automatic storage | |
3805 | duration; */ | |
3806 | t = TREE_OPERAND (t, 0); | |
3807 | ||
3808 | if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t)) | |
3809 | /* A pointer-to-member constant. */ | |
3810 | return true; | |
3811 | ||
3812 | #if 0 | |
3813 | /* FIXME adjust when issue 1197 is fully resolved. For now don't do | |
3814 | any checking here, as we might dereference the pointer later. If | |
3815 | we remove this code, also remove check_automatic_or_tls. */ | |
3816 | i = check_automatic_or_tls (t); | |
3817 | if (i == ck_ok) | |
3818 | return true; | |
3819 | if (i == ck_bad) | |
3820 | { | |
3821 | if (flags & tf_error) | |
3822 | error ("address-of an object %qE with thread local or " | |
3823 | "automatic storage is not a constant expression", t); | |
3824 | return false; | |
3825 | } | |
3826 | #endif | |
2055d27a | 3827 | return RECUR (t, any); |
09b42213 | 3828 | |
3829 | case COMPONENT_REF: | |
3830 | case BIT_FIELD_REF: | |
3831 | case ARROW_EXPR: | |
3832 | case OFFSET_REF: | |
3833 | /* -- a class member access unless its postfix-expression is | |
3834 | of literal type or of pointer to literal type. */ | |
3835 | /* This test would be redundant, as it follows from the | |
3836 | postfix-expression being a potential constant expression. */ | |
2055d27a | 3837 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 3838 | |
3839 | case EXPR_PACK_EXPANSION: | |
2055d27a | 3840 | return RECUR (PACK_EXPANSION_PATTERN (t), want_rval); |
09b42213 | 3841 | |
3842 | case INDIRECT_REF: | |
3843 | { | |
3844 | tree x = TREE_OPERAND (t, 0); | |
3845 | STRIP_NOPS (x); | |
3846 | if (is_this_parameter (x)) | |
3847 | { | |
3848 | if (DECL_CONTEXT (x) | |
3849 | && !DECL_DECLARED_CONSTEXPR_P (DECL_CONTEXT (x))) | |
3850 | { | |
3851 | if (flags & tf_error) | |
3852 | error ("use of %<this%> in a constant expression"); | |
3853 | return false; | |
3854 | } | |
09b42213 | 3855 | return true; |
3856 | } | |
2055d27a | 3857 | return RECUR (x, rval); |
09b42213 | 3858 | } |
3859 | ||
9c96033c | 3860 | case STATEMENT_LIST: |
3861 | { | |
3862 | tree_stmt_iterator i; | |
3863 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
3864 | { | |
2055d27a | 3865 | if (!RECUR (tsi_stmt (i), any)) |
9c96033c | 3866 | return false; |
3867 | } | |
3868 | return true; | |
3869 | } | |
3870 | break; | |
3871 | ||
3872 | case MODIFY_EXPR: | |
3873 | if (cxx_dialect < cxx14) | |
3874 | goto fail; | |
2055d27a | 3875 | if (!RECUR (TREE_OPERAND (t, 0), any)) |
9c96033c | 3876 | return false; |
2055d27a | 3877 | if (!RECUR (TREE_OPERAND (t, 1), rval)) |
9c96033c | 3878 | return false; |
3879 | return true; | |
3880 | ||
3881 | case MODOP_EXPR: | |
3882 | if (cxx_dialect < cxx14) | |
3883 | goto fail; | |
2055d27a | 3884 | if (!RECUR (TREE_OPERAND (t, 0), rval)) |
9c96033c | 3885 | return false; |
2055d27a | 3886 | if (!RECUR (TREE_OPERAND (t, 2), rval)) |
9c96033c | 3887 | return false; |
3888 | return true; | |
3889 | ||
3890 | case IF_STMT: | |
2055d27a | 3891 | if (!RECUR (IF_COND (t), rval)) |
9c96033c | 3892 | return false; |
2055d27a | 3893 | if (!RECUR (THEN_CLAUSE (t), any)) |
9c96033c | 3894 | return false; |
2055d27a | 3895 | if (!RECUR (ELSE_CLAUSE (t), any)) |
9c96033c | 3896 | return false; |
3897 | return true; | |
3898 | ||
3899 | case DO_STMT: | |
2055d27a | 3900 | if (!RECUR (DO_COND (t), rval)) |
9c96033c | 3901 | return false; |
2055d27a | 3902 | if (!RECUR (DO_BODY (t), any)) |
9c96033c | 3903 | return false; |
3904 | return true; | |
3905 | ||
3906 | case FOR_STMT: | |
2055d27a | 3907 | if (!RECUR (FOR_INIT_STMT (t), any)) |
9c96033c | 3908 | return false; |
2055d27a | 3909 | if (!RECUR (FOR_COND (t), rval)) |
9c96033c | 3910 | return false; |
2055d27a | 3911 | if (!RECUR (FOR_EXPR (t), any)) |
9c96033c | 3912 | return false; |
2055d27a | 3913 | if (!RECUR (FOR_BODY (t), any)) |
9c96033c | 3914 | return false; |
3915 | return true; | |
3916 | ||
3917 | case WHILE_STMT: | |
2055d27a | 3918 | if (!RECUR (WHILE_COND (t), rval)) |
9c96033c | 3919 | return false; |
2055d27a | 3920 | if (!RECUR (WHILE_BODY (t), any)) |
9c96033c | 3921 | return false; |
3922 | return true; | |
3923 | ||
3924 | case SWITCH_STMT: | |
2055d27a | 3925 | if (!RECUR (SWITCH_STMT_COND (t), rval)) |
9c96033c | 3926 | return false; |
2055d27a | 3927 | if (!RECUR (SWITCH_STMT_BODY (t), any)) |
9c96033c | 3928 | return false; |
3929 | return true; | |
3930 | ||
da7981e0 | 3931 | case STMT_EXPR: |
2055d27a | 3932 | return RECUR (STMT_EXPR_STMT (t), rval); |
da7981e0 | 3933 | |
09b42213 | 3934 | case LAMBDA_EXPR: |
3935 | case DYNAMIC_CAST_EXPR: | |
3936 | case PSEUDO_DTOR_EXPR: | |
09b42213 | 3937 | case NEW_EXPR: |
3938 | case VEC_NEW_EXPR: | |
3939 | case DELETE_EXPR: | |
3940 | case VEC_DELETE_EXPR: | |
3941 | case THROW_EXPR: | |
09b42213 | 3942 | case OMP_ATOMIC: |
3943 | case OMP_ATOMIC_READ: | |
3944 | case OMP_ATOMIC_CAPTURE_OLD: | |
3945 | case OMP_ATOMIC_CAPTURE_NEW: | |
3946 | /* GCC internal stuff. */ | |
3947 | case VA_ARG_EXPR: | |
3948 | case OBJ_TYPE_REF: | |
09b42213 | 3949 | case TRANSACTION_EXPR: |
9c96033c | 3950 | case ASM_EXPR: |
3951 | fail: | |
09b42213 | 3952 | if (flags & tf_error) |
3953 | error ("expression %qE is not a constant-expression", t); | |
3954 | return false; | |
3955 | ||
3956 | case TYPEID_EXPR: | |
3957 | /* -- a typeid expression whose operand is of polymorphic | |
3958 | class type; */ | |
3959 | { | |
3960 | tree e = TREE_OPERAND (t, 0); | |
3961 | if (!TYPE_P (e) && !type_dependent_expression_p (e) | |
3962 | && TYPE_POLYMORPHIC_P (TREE_TYPE (e))) | |
3963 | { | |
3964 | if (flags & tf_error) | |
3965 | error ("typeid-expression is not a constant expression " | |
3966 | "because %qE is of polymorphic type", e); | |
3967 | return false; | |
3968 | } | |
3969 | return true; | |
3970 | } | |
3971 | ||
3972 | case MINUS_EXPR: | |
3973 | /* -- a subtraction where both operands are pointers. */ | |
3974 | if (TYPE_PTR_P (TREE_OPERAND (t, 0)) | |
3975 | && TYPE_PTR_P (TREE_OPERAND (t, 1))) | |
3976 | { | |
3977 | if (flags & tf_error) | |
3978 | error ("difference of two pointer expressions is not " | |
3979 | "a constant expression"); | |
3980 | return false; | |
3981 | } | |
3982 | want_rval = true; | |
3983 | goto binary; | |
3984 | ||
3985 | case LT_EXPR: | |
3986 | case LE_EXPR: | |
3987 | case GT_EXPR: | |
3988 | case GE_EXPR: | |
3989 | case EQ_EXPR: | |
3990 | case NE_EXPR: | |
3991 | /* -- a relational or equality operator where at least | |
3992 | one of the operands is a pointer. */ | |
3993 | if (TYPE_PTR_P (TREE_OPERAND (t, 0)) | |
3994 | || TYPE_PTR_P (TREE_OPERAND (t, 1))) | |
3995 | { | |
3996 | if (flags & tf_error) | |
3997 | error ("pointer comparison expression is not a " | |
3998 | "constant expression"); | |
3999 | return false; | |
4000 | } | |
4001 | want_rval = true; | |
4002 | goto binary; | |
4003 | ||
9c96033c | 4004 | case PREINCREMENT_EXPR: |
4005 | case POSTINCREMENT_EXPR: | |
4006 | case PREDECREMENT_EXPR: | |
4007 | case POSTDECREMENT_EXPR: | |
4008 | if (cxx_dialect < cxx14) | |
4009 | goto fail; | |
4010 | goto unary; | |
4011 | ||
09b42213 | 4012 | case BIT_NOT_EXPR: |
4013 | /* A destructor. */ | |
4014 | if (TYPE_P (TREE_OPERAND (t, 0))) | |
4015 | return true; | |
4016 | /* else fall through. */ | |
4017 | ||
4018 | case REALPART_EXPR: | |
4019 | case IMAGPART_EXPR: | |
4020 | case CONJ_EXPR: | |
4021 | case SAVE_EXPR: | |
4022 | case FIX_TRUNC_EXPR: | |
4023 | case FLOAT_EXPR: | |
4024 | case NEGATE_EXPR: | |
4025 | case ABS_EXPR: | |
4026 | case TRUTH_NOT_EXPR: | |
4027 | case FIXED_CONVERT_EXPR: | |
4028 | case UNARY_PLUS_EXPR: | |
9c96033c | 4029 | unary: |
2055d27a | 4030 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 4031 | |
4032 | case CAST_EXPR: | |
4033 | case CONST_CAST_EXPR: | |
4034 | case STATIC_CAST_EXPR: | |
4035 | case REINTERPRET_CAST_EXPR: | |
4036 | case IMPLICIT_CONV_EXPR: | |
4037 | if (cxx_dialect < cxx11 | |
4038 | && !dependent_type_p (TREE_TYPE (t)) | |
4039 | && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t))) | |
4040 | /* In C++98, a conversion to non-integral type can't be part of a | |
4041 | constant expression. */ | |
4042 | { | |
4043 | if (flags & tf_error) | |
4044 | error ("cast to non-integral type %qT in a constant expression", | |
4045 | TREE_TYPE (t)); | |
4046 | return false; | |
4047 | } | |
4048 | ||
2055d27a | 4049 | return (RECUR (TREE_OPERAND (t, 0), |
4050 | TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE)); | |
09b42213 | 4051 | |
9c96033c | 4052 | case BIND_EXPR: |
2055d27a | 4053 | return RECUR (BIND_EXPR_BODY (t), want_rval); |
9c96033c | 4054 | |
4055 | case WITH_CLEANUP_EXPR: | |
4056 | case CLEANUP_POINT_EXPR: | |
4057 | case MUST_NOT_THROW_EXPR: | |
4058 | case TRY_CATCH_EXPR: | |
4059 | case EH_SPEC_BLOCK: | |
4060 | case EXPR_STMT: | |
09b42213 | 4061 | case PAREN_EXPR: |
9c96033c | 4062 | case DECL_EXPR: |
09b42213 | 4063 | case NON_DEPENDENT_EXPR: |
4064 | /* For convenience. */ | |
4065 | case RETURN_EXPR: | |
2055d27a | 4066 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 4067 | |
4068 | case SCOPE_REF: | |
2055d27a | 4069 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 4070 | |
4071 | case TARGET_EXPR: | |
4072 | if (!literal_type_p (TREE_TYPE (t))) | |
4073 | { | |
4074 | if (flags & tf_error) | |
4075 | { | |
4076 | error ("temporary of non-literal type %qT in a " | |
4077 | "constant expression", TREE_TYPE (t)); | |
4078 | explain_non_literal_class (TREE_TYPE (t)); | |
4079 | } | |
4080 | return false; | |
4081 | } | |
4082 | case INIT_EXPR: | |
2055d27a | 4083 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 4084 | |
4085 | case CONSTRUCTOR: | |
4086 | { | |
4087 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
4088 | constructor_elt *ce; | |
4089 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2055d27a | 4090 | if (!RECUR (ce->value, want_rval)) |
09b42213 | 4091 | return false; |
4092 | return true; | |
4093 | } | |
4094 | ||
4095 | case TREE_LIST: | |
4096 | { | |
4097 | gcc_assert (TREE_PURPOSE (t) == NULL_TREE | |
4098 | || DECL_P (TREE_PURPOSE (t))); | |
2055d27a | 4099 | if (!RECUR (TREE_VALUE (t), want_rval)) |
09b42213 | 4100 | return false; |
4101 | if (TREE_CHAIN (t) == NULL_TREE) | |
4102 | return true; | |
2055d27a | 4103 | return RECUR (TREE_CHAIN (t), want_rval); |
09b42213 | 4104 | } |
4105 | ||
4106 | case TRUNC_DIV_EXPR: | |
4107 | case CEIL_DIV_EXPR: | |
4108 | case FLOOR_DIV_EXPR: | |
4109 | case ROUND_DIV_EXPR: | |
4110 | case TRUNC_MOD_EXPR: | |
4111 | case CEIL_MOD_EXPR: | |
4112 | case ROUND_MOD_EXPR: | |
4113 | { | |
4114 | tree denom = TREE_OPERAND (t, 1); | |
2055d27a | 4115 | if (!RECUR (denom, rval)) |
09b42213 | 4116 | return false; |
4117 | /* We can't call cxx_eval_outermost_constant_expr on an expression | |
21131a05 | 4118 | that hasn't been through instantiate_non_dependent_expr yet. */ |
09b42213 | 4119 | if (!processing_template_decl) |
4120 | denom = cxx_eval_outermost_constant_expr (denom, true); | |
4121 | if (integer_zerop (denom)) | |
4122 | { | |
4123 | if (flags & tf_error) | |
4124 | error ("division by zero is not a constant-expression"); | |
4125 | return false; | |
4126 | } | |
4127 | else | |
4128 | { | |
4129 | want_rval = true; | |
2055d27a | 4130 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 4131 | } |
4132 | } | |
4133 | ||
4134 | case COMPOUND_EXPR: | |
4135 | { | |
4136 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
4137 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
4138 | introduced by build_call_a. */ | |
4139 | tree op0 = TREE_OPERAND (t, 0); | |
4140 | tree op1 = TREE_OPERAND (t, 1); | |
4141 | STRIP_NOPS (op1); | |
4142 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
4143 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
2055d27a | 4144 | return RECUR (op0, want_rval); |
09b42213 | 4145 | else |
4146 | goto binary; | |
4147 | } | |
4148 | ||
4149 | /* If the first operand is the non-short-circuit constant, look at | |
4150 | the second operand; otherwise we only care about the first one for | |
4151 | potentiality. */ | |
4152 | case TRUTH_AND_EXPR: | |
4153 | case TRUTH_ANDIF_EXPR: | |
4154 | tmp = boolean_true_node; | |
4155 | goto truth; | |
4156 | case TRUTH_OR_EXPR: | |
4157 | case TRUTH_ORIF_EXPR: | |
4158 | tmp = boolean_false_node; | |
4159 | truth: | |
4160 | { | |
4161 | tree op = TREE_OPERAND (t, 0); | |
2055d27a | 4162 | if (!RECUR (op, rval)) |
09b42213 | 4163 | return false; |
4164 | if (!processing_template_decl) | |
4165 | op = cxx_eval_outermost_constant_expr (op, true); | |
4166 | if (tree_int_cst_equal (op, tmp)) | |
2055d27a | 4167 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 4168 | else |
4169 | return true; | |
4170 | } | |
4171 | ||
4172 | case PLUS_EXPR: | |
4173 | case MULT_EXPR: | |
4174 | case POINTER_PLUS_EXPR: | |
4175 | case RDIV_EXPR: | |
4176 | case EXACT_DIV_EXPR: | |
4177 | case MIN_EXPR: | |
4178 | case MAX_EXPR: | |
4179 | case LSHIFT_EXPR: | |
4180 | case RSHIFT_EXPR: | |
4181 | case LROTATE_EXPR: | |
4182 | case RROTATE_EXPR: | |
4183 | case BIT_IOR_EXPR: | |
4184 | case BIT_XOR_EXPR: | |
4185 | case BIT_AND_EXPR: | |
4186 | case TRUTH_XOR_EXPR: | |
4187 | case UNORDERED_EXPR: | |
4188 | case ORDERED_EXPR: | |
4189 | case UNLT_EXPR: | |
4190 | case UNLE_EXPR: | |
4191 | case UNGT_EXPR: | |
4192 | case UNGE_EXPR: | |
4193 | case UNEQ_EXPR: | |
4194 | case LTGT_EXPR: | |
4195 | case RANGE_EXPR: | |
4196 | case COMPLEX_EXPR: | |
4197 | want_rval = true; | |
4198 | /* Fall through. */ | |
4199 | case ARRAY_REF: | |
4200 | case ARRAY_RANGE_REF: | |
4201 | case MEMBER_REF: | |
4202 | case DOTSTAR_EXPR: | |
4203 | binary: | |
4204 | for (i = 0; i < 2; ++i) | |
2055d27a | 4205 | if (!RECUR (TREE_OPERAND (t, i), want_rval)) |
09b42213 | 4206 | return false; |
4207 | return true; | |
4208 | ||
4209 | case CILK_SYNC_STMT: | |
4210 | case CILK_SPAWN_STMT: | |
4211 | case ARRAY_NOTATION_REF: | |
4212 | return false; | |
4213 | ||
4214 | case FMA_EXPR: | |
4215 | case VEC_PERM_EXPR: | |
4216 | for (i = 0; i < 3; ++i) | |
2055d27a | 4217 | if (!RECUR (TREE_OPERAND (t, i), true)) |
09b42213 | 4218 | return false; |
4219 | return true; | |
4220 | ||
4221 | case COND_EXPR: | |
4222 | case VEC_COND_EXPR: | |
4223 | /* If the condition is a known constant, we know which of the legs we | |
4224 | care about; otherwise we only require that the condition and | |
4225 | either of the legs be potentially constant. */ | |
4226 | tmp = TREE_OPERAND (t, 0); | |
2055d27a | 4227 | if (!RECUR (tmp, rval)) |
09b42213 | 4228 | return false; |
4229 | if (!processing_template_decl) | |
4230 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
4231 | if (integer_zerop (tmp)) | |
2055d27a | 4232 | return RECUR (TREE_OPERAND (t, 2), want_rval); |
09b42213 | 4233 | else if (TREE_CODE (tmp) == INTEGER_CST) |
2055d27a | 4234 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 4235 | for (i = 1; i < 3; ++i) |
4236 | if (potential_constant_expression_1 (TREE_OPERAND (t, i), | |
2055d27a | 4237 | want_rval, strict, tf_none)) |
09b42213 | 4238 | return true; |
4239 | if (flags & tf_error) | |
4240 | error ("expression %qE is not a constant-expression", t); | |
4241 | return false; | |
4242 | ||
4243 | case VEC_INIT_EXPR: | |
4244 | if (VEC_INIT_EXPR_IS_CONSTEXPR (t)) | |
4245 | return true; | |
4246 | if (flags & tf_error) | |
4247 | { | |
4248 | error ("non-constant array initialization"); | |
4249 | diagnose_non_constexpr_vec_init (t); | |
4250 | } | |
4251 | return false; | |
4252 | ||
4253 | default: | |
4254 | if (objc_is_property_ref (t)) | |
4255 | return false; | |
4256 | ||
4257 | sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t))); | |
4258 | gcc_unreachable(); | |
4259 | return false; | |
4260 | } | |
2055d27a | 4261 | #undef RECUR |
09b42213 | 4262 | } |
4263 | ||
4264 | /* The main entry point to the above. */ | |
4265 | ||
4266 | bool | |
4267 | potential_constant_expression (tree t) | |
4268 | { | |
2055d27a | 4269 | return potential_constant_expression_1 (t, false, true, tf_none); |
4270 | } | |
4271 | ||
4272 | bool | |
4273 | potential_static_init_expression (tree t) | |
4274 | { | |
4275 | return potential_constant_expression_1 (t, false, false, tf_none); | |
09b42213 | 4276 | } |
4277 | ||
4278 | /* As above, but require a constant rvalue. */ | |
4279 | ||
4280 | bool | |
4281 | potential_rvalue_constant_expression (tree t) | |
4282 | { | |
2055d27a | 4283 | return potential_constant_expression_1 (t, true, true, tf_none); |
09b42213 | 4284 | } |
4285 | ||
4286 | /* Like above, but complain about non-constant expressions. */ | |
4287 | ||
4288 | bool | |
4289 | require_potential_constant_expression (tree t) | |
4290 | { | |
2055d27a | 4291 | return potential_constant_expression_1 (t, false, true, tf_warning_or_error); |
09b42213 | 4292 | } |
4293 | ||
4294 | /* Cross product of the above. */ | |
4295 | ||
4296 | bool | |
4297 | require_potential_rvalue_constant_expression (tree t) | |
4298 | { | |
2055d27a | 4299 | return potential_constant_expression_1 (t, true, true, tf_warning_or_error); |
09b42213 | 4300 | } |
4301 | ||
4302 | #include "gt-cp-constexpr.h" |