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f9885b8a | 1 | /* Perform -*- C++ -*- constant expression evaluation, including calls to |
2 | constexpr functions. These routines are used both during actual parsing | |
09b42213 | 3 | and during the instantiation of template functions. |
4 | ||
aad93da1 | 5 | Copyright (C) 1998-2017 Free Software Foundation, Inc. |
09b42213 | 6 | |
7 | This file is part of GCC. | |
8 | ||
9 | GCC is free software; you can redistribute it and/or modify it | |
10 | under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 3, or (at your option) | |
12 | any later version. | |
13 | ||
14 | GCC is distributed in the hope that it will be useful, but | |
15 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
20 | along with GCC; see the file COPYING3. If not see | |
21 | <http://www.gnu.org/licenses/>. */ | |
22 | ||
23 | #include "config.h" | |
24 | #include "system.h" | |
25 | #include "coretypes.h" | |
09b42213 | 26 | #include "cp-tree.h" |
4cba6f60 | 27 | #include "varasm.h" |
09b42213 | 28 | #include "c-family/c-objc.h" |
29 | #include "tree-iterator.h" | |
30 | #include "gimplify.h" | |
31 | #include "builtins.h" | |
9c96033c | 32 | #include "tree-inline.h" |
6b71bdb4 | 33 | #include "ubsan.h" |
732905bb | 34 | #include "gimple-fold.h" |
c300fe28 | 35 | #include "timevar.h" |
09b42213 | 36 | |
37 | static bool verify_constant (tree, bool, bool *, bool *); | |
38 | #define VERIFY_CONSTANT(X) \ | |
39 | do { \ | |
f83e6885 | 40 | if (verify_constant ((X), ctx->quiet, non_constant_p, overflow_p)) \ |
09b42213 | 41 | return t; \ |
42 | } while (0) | |
43 | ||
44 | /* Returns true iff FUN is an instantiation of a constexpr function | |
45 | template or a defaulted constexpr function. */ | |
46 | ||
47 | bool | |
48 | is_instantiation_of_constexpr (tree fun) | |
49 | { | |
50 | return ((DECL_TEMPLOID_INSTANTIATION (fun) | |
51 | && DECL_DECLARED_CONSTEXPR_P (DECL_TI_TEMPLATE (fun))) | |
52 | || (DECL_DEFAULTED_FN (fun) | |
53 | && DECL_DECLARED_CONSTEXPR_P (fun))); | |
54 | } | |
55 | ||
56 | /* Return true if T is a literal type. */ | |
57 | ||
58 | bool | |
59 | literal_type_p (tree t) | |
60 | { | |
61 | if (SCALAR_TYPE_P (t) | |
76249021 | 62 | || VECTOR_TYPE_P (t) |
dd418b39 | 63 | || TREE_CODE (t) == REFERENCE_TYPE |
64 | || (VOID_TYPE_P (t) && cxx_dialect >= cxx14)) | |
09b42213 | 65 | return true; |
66 | if (CLASS_TYPE_P (t)) | |
67 | { | |
68 | t = complete_type (t); | |
69 | gcc_assert (COMPLETE_TYPE_P (t) || errorcount); | |
70 | return CLASSTYPE_LITERAL_P (t); | |
71 | } | |
72 | if (TREE_CODE (t) == ARRAY_TYPE) | |
73 | return literal_type_p (strip_array_types (t)); | |
74 | return false; | |
75 | } | |
76 | ||
77 | /* If DECL is a variable declared `constexpr', require its type | |
78 | be literal. Return the DECL if OK, otherwise NULL. */ | |
79 | ||
80 | tree | |
81 | ensure_literal_type_for_constexpr_object (tree decl) | |
82 | { | |
83 | tree type = TREE_TYPE (decl); | |
84 | if (VAR_P (decl) | |
85 | && (DECL_DECLARED_CONSTEXPR_P (decl) | |
86 | || var_in_constexpr_fn (decl)) | |
87 | && !processing_template_decl) | |
88 | { | |
89 | tree stype = strip_array_types (type); | |
90 | if (CLASS_TYPE_P (stype) && !COMPLETE_TYPE_P (complete_type (stype))) | |
91 | /* Don't complain here, we'll complain about incompleteness | |
92 | when we try to initialize the variable. */; | |
93 | else if (!literal_type_p (type)) | |
94 | { | |
95 | if (DECL_DECLARED_CONSTEXPR_P (decl)) | |
e45408ff | 96 | { |
5967b28b | 97 | error ("the type %qT of %<constexpr%> variable %qD " |
98 | "is not literal", type, decl); | |
e45408ff | 99 | explain_non_literal_class (type); |
100 | } | |
09b42213 | 101 | else |
9c96033c | 102 | { |
b7e4a558 | 103 | if (!is_instantiation_of_constexpr (current_function_decl)) |
e45408ff | 104 | { |
105 | error ("variable %qD of non-literal type %qT in %<constexpr%> " | |
106 | "function", decl, type); | |
107 | explain_non_literal_class (type); | |
108 | } | |
9c96033c | 109 | cp_function_chain->invalid_constexpr = true; |
110 | } | |
09b42213 | 111 | return NULL; |
112 | } | |
113 | } | |
114 | return decl; | |
115 | } | |
116 | ||
117 | /* Representation of entries in the constexpr function definition table. */ | |
118 | ||
119 | struct GTY((for_user)) constexpr_fundef { | |
120 | tree decl; | |
121 | tree body; | |
122 | }; | |
123 | ||
b594087e | 124 | struct constexpr_fundef_hasher : ggc_ptr_hash<constexpr_fundef> |
09b42213 | 125 | { |
126 | static hashval_t hash (constexpr_fundef *); | |
127 | static bool equal (constexpr_fundef *, constexpr_fundef *); | |
128 | }; | |
129 | ||
130 | /* This table holds all constexpr function definitions seen in | |
131 | the current translation unit. */ | |
132 | ||
133 | static GTY (()) hash_table<constexpr_fundef_hasher> *constexpr_fundef_table; | |
134 | ||
135 | /* Utility function used for managing the constexpr function table. | |
136 | Return true if the entries pointed to by P and Q are for the | |
137 | same constexpr function. */ | |
138 | ||
139 | inline bool | |
140 | constexpr_fundef_hasher::equal (constexpr_fundef *lhs, constexpr_fundef *rhs) | |
141 | { | |
142 | return lhs->decl == rhs->decl; | |
143 | } | |
144 | ||
145 | /* Utility function used for managing the constexpr function table. | |
146 | Return a hash value for the entry pointed to by Q. */ | |
147 | ||
148 | inline hashval_t | |
149 | constexpr_fundef_hasher::hash (constexpr_fundef *fundef) | |
150 | { | |
151 | return DECL_UID (fundef->decl); | |
152 | } | |
153 | ||
154 | /* Return a previously saved definition of function FUN. */ | |
155 | ||
156 | static constexpr_fundef * | |
157 | retrieve_constexpr_fundef (tree fun) | |
158 | { | |
159 | constexpr_fundef fundef = { NULL, NULL }; | |
160 | if (constexpr_fundef_table == NULL) | |
161 | return NULL; | |
162 | ||
163 | fundef.decl = fun; | |
164 | return constexpr_fundef_table->find (&fundef); | |
165 | } | |
166 | ||
167 | /* Check whether the parameter and return types of FUN are valid for a | |
168 | constexpr function, and complain if COMPLAIN. */ | |
169 | ||
33603066 | 170 | bool |
09b42213 | 171 | is_valid_constexpr_fn (tree fun, bool complain) |
172 | { | |
173 | bool ret = true; | |
174 | ||
7896267d | 175 | if (DECL_INHERITED_CTOR (fun) |
09b42213 | 176 | && TREE_CODE (fun) == TEMPLATE_DECL) |
177 | { | |
178 | ret = false; | |
179 | if (complain) | |
5967b28b | 180 | error ("inherited constructor %qD is not %<constexpr%>", |
7896267d | 181 | DECL_INHERITED_CTOR (fun)); |
09b42213 | 182 | } |
183 | else | |
184 | { | |
185 | for (tree parm = FUNCTION_FIRST_USER_PARM (fun); | |
186 | parm != NULL_TREE; parm = TREE_CHAIN (parm)) | |
187 | if (!literal_type_p (TREE_TYPE (parm))) | |
188 | { | |
189 | ret = false; | |
190 | if (complain) | |
191 | { | |
5967b28b | 192 | error ("invalid type for parameter %d of %<constexpr%> " |
09b42213 | 193 | "function %q+#D", DECL_PARM_INDEX (parm), fun); |
194 | explain_non_literal_class (TREE_TYPE (parm)); | |
195 | } | |
196 | } | |
197 | } | |
198 | ||
672871ce | 199 | if (LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) && cxx_dialect < cxx17) |
200 | { | |
201 | ret = false; | |
202 | if (complain) | |
203 | inform (DECL_SOURCE_LOCATION (fun), | |
5967b28b | 204 | "lambdas are implicitly %<constexpr%> only in C++17 and later"); |
672871ce | 205 | } |
206 | else if (!DECL_CONSTRUCTOR_P (fun)) | |
09b42213 | 207 | { |
208 | tree rettype = TREE_TYPE (TREE_TYPE (fun)); | |
209 | if (!literal_type_p (rettype)) | |
210 | { | |
211 | ret = false; | |
212 | if (complain) | |
213 | { | |
5967b28b | 214 | error ("invalid return type %qT of %<constexpr%> function %q+D", |
09b42213 | 215 | rettype, fun); |
216 | explain_non_literal_class (rettype); | |
217 | } | |
218 | } | |
219 | ||
d66f34cf | 220 | /* C++14 DR 1684 removed this restriction. */ |
221 | if (cxx_dialect < cxx14 | |
222 | && DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
09b42213 | 223 | && !CLASSTYPE_LITERAL_P (DECL_CONTEXT (fun))) |
224 | { | |
225 | ret = false; | |
d66f34cf | 226 | if (complain |
227 | && pedwarn (DECL_SOURCE_LOCATION (fun), OPT_Wpedantic, | |
5967b28b | 228 | "enclosing class of %<constexpr%> non-static member " |
d66f34cf | 229 | "function %q+#D is not a literal type", fun)) |
230 | explain_non_literal_class (DECL_CONTEXT (fun)); | |
09b42213 | 231 | } |
232 | } | |
233 | else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun))) | |
234 | { | |
235 | ret = false; | |
236 | if (complain) | |
237 | error ("%q#T has virtual base classes", DECL_CONTEXT (fun)); | |
238 | } | |
239 | ||
240 | return ret; | |
241 | } | |
242 | ||
243 | /* Subroutine of build_data_member_initialization. MEMBER is a COMPONENT_REF | |
244 | for a member of an anonymous aggregate, INIT is the initializer for that | |
245 | member, and VEC_OUTER is the vector of constructor elements for the class | |
246 | whose constructor we are processing. Add the initializer to the vector | |
247 | and return true to indicate success. */ | |
248 | ||
249 | static bool | |
250 | build_anon_member_initialization (tree member, tree init, | |
251 | vec<constructor_elt, va_gc> **vec_outer) | |
252 | { | |
253 | /* MEMBER presents the relevant fields from the inside out, but we need | |
254 | to build up the initializer from the outside in so that we can reuse | |
255 | previously built CONSTRUCTORs if this is, say, the second field in an | |
256 | anonymous struct. So we use a vec as a stack. */ | |
257 | auto_vec<tree, 2> fields; | |
258 | do | |
259 | { | |
260 | fields.safe_push (TREE_OPERAND (member, 1)); | |
261 | member = TREE_OPERAND (member, 0); | |
262 | } | |
263 | while (ANON_AGGR_TYPE_P (TREE_TYPE (member)) | |
264 | && TREE_CODE (member) == COMPONENT_REF); | |
265 | ||
266 | /* VEC has the constructor elements vector for the context of FIELD. | |
267 | If FIELD is an anonymous aggregate, we will push inside it. */ | |
268 | vec<constructor_elt, va_gc> **vec = vec_outer; | |
269 | tree field; | |
270 | while (field = fields.pop(), | |
271 | ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
272 | { | |
273 | tree ctor; | |
274 | /* If there is already an outer constructor entry for the anonymous | |
275 | aggregate FIELD, use it; otherwise, insert one. */ | |
276 | if (vec_safe_is_empty (*vec) | |
277 | || (*vec)->last().index != field) | |
278 | { | |
279 | ctor = build_constructor (TREE_TYPE (field), NULL); | |
280 | CONSTRUCTOR_APPEND_ELT (*vec, field, ctor); | |
281 | } | |
282 | else | |
283 | ctor = (*vec)->last().value; | |
284 | vec = &CONSTRUCTOR_ELTS (ctor); | |
285 | } | |
286 | ||
287 | /* Now we're at the innermost field, the one that isn't an anonymous | |
288 | aggregate. Add its initializer to the CONSTRUCTOR and we're done. */ | |
289 | gcc_assert (fields.is_empty()); | |
290 | CONSTRUCTOR_APPEND_ELT (*vec, field, init); | |
291 | ||
292 | return true; | |
293 | } | |
294 | ||
295 | /* Subroutine of build_constexpr_constructor_member_initializers. | |
296 | The expression tree T represents a data member initialization | |
297 | in a (constexpr) constructor definition. Build a pairing of | |
298 | the data member with its initializer, and prepend that pair | |
299 | to the existing initialization pair INITS. */ | |
300 | ||
301 | static bool | |
302 | build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec) | |
303 | { | |
304 | tree member, init; | |
305 | if (TREE_CODE (t) == CLEANUP_POINT_EXPR) | |
306 | t = TREE_OPERAND (t, 0); | |
307 | if (TREE_CODE (t) == EXPR_STMT) | |
308 | t = TREE_OPERAND (t, 0); | |
309 | if (t == error_mark_node) | |
310 | return false; | |
311 | if (TREE_CODE (t) == STATEMENT_LIST) | |
312 | { | |
313 | tree_stmt_iterator i; | |
314 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
315 | { | |
316 | if (! build_data_member_initialization (tsi_stmt (i), vec)) | |
317 | return false; | |
318 | } | |
319 | return true; | |
320 | } | |
321 | if (TREE_CODE (t) == CLEANUP_STMT) | |
322 | { | |
323 | /* We can't see a CLEANUP_STMT in a constructor for a literal class, | |
324 | but we can in a constexpr constructor for a non-literal class. Just | |
325 | ignore it; either all the initialization will be constant, in which | |
326 | case the cleanup can't run, or it can't be constexpr. | |
327 | Still recurse into CLEANUP_BODY. */ | |
328 | return build_data_member_initialization (CLEANUP_BODY (t), vec); | |
329 | } | |
330 | if (TREE_CODE (t) == CONVERT_EXPR) | |
331 | t = TREE_OPERAND (t, 0); | |
332 | if (TREE_CODE (t) == INIT_EXPR | |
9c96033c | 333 | /* vptr initialization shows up as a MODIFY_EXPR. In C++14 we only |
334 | use what this function builds for cx_check_missing_mem_inits, and | |
335 | assignment in the ctor body doesn't count. */ | |
336 | || (cxx_dialect < cxx14 && TREE_CODE (t) == MODIFY_EXPR)) | |
09b42213 | 337 | { |
338 | member = TREE_OPERAND (t, 0); | |
339 | init = break_out_target_exprs (TREE_OPERAND (t, 1)); | |
340 | } | |
341 | else if (TREE_CODE (t) == CALL_EXPR) | |
342 | { | |
9c96033c | 343 | tree fn = get_callee_fndecl (t); |
344 | if (!fn || !DECL_CONSTRUCTOR_P (fn)) | |
345 | /* We're only interested in calls to subobject constructors. */ | |
346 | return true; | |
09b42213 | 347 | member = CALL_EXPR_ARG (t, 0); |
348 | /* We don't use build_cplus_new here because it complains about | |
349 | abstract bases. Leaving the call unwrapped means that it has the | |
350 | wrong type, but cxx_eval_constant_expression doesn't care. */ | |
351 | init = break_out_target_exprs (t); | |
352 | } | |
353 | else if (TREE_CODE (t) == BIND_EXPR) | |
354 | return build_data_member_initialization (BIND_EXPR_BODY (t), vec); | |
09b42213 | 355 | else |
9c96033c | 356 | /* Don't add anything else to the CONSTRUCTOR. */ |
357 | return true; | |
09b42213 | 358 | if (INDIRECT_REF_P (member)) |
359 | member = TREE_OPERAND (member, 0); | |
360 | if (TREE_CODE (member) == NOP_EXPR) | |
361 | { | |
362 | tree op = member; | |
363 | STRIP_NOPS (op); | |
364 | if (TREE_CODE (op) == ADDR_EXPR) | |
365 | { | |
366 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
367 | (TREE_TYPE (TREE_TYPE (op)), | |
368 | TREE_TYPE (TREE_TYPE (member)))); | |
369 | /* Initializing a cv-qualified member; we need to look through | |
370 | the const_cast. */ | |
371 | member = op; | |
372 | } | |
373 | else if (op == current_class_ptr | |
374 | && (same_type_ignoring_top_level_qualifiers_p | |
375 | (TREE_TYPE (TREE_TYPE (member)), | |
376 | current_class_type))) | |
377 | /* Delegating constructor. */ | |
378 | member = op; | |
379 | else | |
380 | { | |
381 | /* This is an initializer for an empty base; keep it for now so | |
382 | we can check it in cxx_eval_bare_aggregate. */ | |
383 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (member)))); | |
384 | } | |
385 | } | |
386 | if (TREE_CODE (member) == ADDR_EXPR) | |
387 | member = TREE_OPERAND (member, 0); | |
388 | if (TREE_CODE (member) == COMPONENT_REF) | |
389 | { | |
390 | tree aggr = TREE_OPERAND (member, 0); | |
4952bc85 | 391 | if (TREE_CODE (aggr) == VAR_DECL) |
392 | /* Initializing a local variable, don't add anything. */ | |
393 | return true; | |
09b42213 | 394 | if (TREE_CODE (aggr) != COMPONENT_REF) |
395 | /* Normal member initialization. */ | |
396 | member = TREE_OPERAND (member, 1); | |
397 | else if (ANON_AGGR_TYPE_P (TREE_TYPE (aggr))) | |
398 | /* Initializing a member of an anonymous union. */ | |
399 | return build_anon_member_initialization (member, init, vec); | |
400 | else | |
401 | /* We're initializing a vtable pointer in a base. Leave it as | |
402 | COMPONENT_REF so we remember the path to get to the vfield. */ | |
403 | gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node); | |
404 | } | |
405 | ||
c678e23e | 406 | /* Value-initialization can produce multiple initializers for the |
407 | same field; use the last one. */ | |
408 | if (!vec_safe_is_empty (*vec) && (*vec)->last().index == member) | |
409 | (*vec)->last().value = init; | |
410 | else | |
411 | CONSTRUCTOR_APPEND_ELT (*vec, member, init); | |
09b42213 | 412 | return true; |
413 | } | |
414 | ||
415 | /* Subroutine of check_constexpr_ctor_body_1 and constexpr_fn_retval. | |
416 | In C++11 mode checks that the TYPE_DECLs in the BIND_EXPR_VARS of a | |
417 | BIND_EXPR conform to 7.1.5/3/4 on typedef and alias declarations. */ | |
418 | ||
419 | static bool | |
420 | check_constexpr_bind_expr_vars (tree t) | |
421 | { | |
422 | gcc_assert (TREE_CODE (t) == BIND_EXPR); | |
423 | ||
09b42213 | 424 | for (tree var = BIND_EXPR_VARS (t); var; var = DECL_CHAIN (var)) |
425 | if (TREE_CODE (var) == TYPE_DECL | |
04103c39 | 426 | && DECL_IMPLICIT_TYPEDEF_P (var) |
427 | && !LAMBDA_TYPE_P (TREE_TYPE (var))) | |
09b42213 | 428 | return false; |
429 | return true; | |
430 | } | |
431 | ||
432 | /* Subroutine of check_constexpr_ctor_body. */ | |
433 | ||
434 | static bool | |
435 | check_constexpr_ctor_body_1 (tree last, tree list) | |
436 | { | |
437 | switch (TREE_CODE (list)) | |
438 | { | |
439 | case DECL_EXPR: | |
810702a2 | 440 | if (TREE_CODE (DECL_EXPR_DECL (list)) == USING_DECL |
441 | || TREE_CODE (DECL_EXPR_DECL (list)) == TYPE_DECL) | |
09b42213 | 442 | return true; |
09b42213 | 443 | return false; |
444 | ||
445 | case CLEANUP_POINT_EXPR: | |
446 | return check_constexpr_ctor_body (last, TREE_OPERAND (list, 0), | |
447 | /*complain=*/false); | |
448 | ||
449 | case BIND_EXPR: | |
450 | if (!check_constexpr_bind_expr_vars (list) | |
451 | || !check_constexpr_ctor_body (last, BIND_EXPR_BODY (list), | |
452 | /*complain=*/false)) | |
453 | return false; | |
454 | return true; | |
455 | ||
456 | case USING_STMT: | |
457 | case STATIC_ASSERT: | |
90567983 | 458 | case DEBUG_BEGIN_STMT: |
09b42213 | 459 | return true; |
460 | ||
461 | default: | |
462 | return false; | |
463 | } | |
464 | } | |
465 | ||
466 | /* Make sure that there are no statements after LAST in the constructor | |
467 | body represented by LIST. */ | |
468 | ||
469 | bool | |
470 | check_constexpr_ctor_body (tree last, tree list, bool complain) | |
471 | { | |
9c96033c | 472 | /* C++14 doesn't require a constexpr ctor to have an empty body. */ |
473 | if (cxx_dialect >= cxx14) | |
474 | return true; | |
475 | ||
09b42213 | 476 | bool ok = true; |
477 | if (TREE_CODE (list) == STATEMENT_LIST) | |
478 | { | |
479 | tree_stmt_iterator i = tsi_last (list); | |
480 | for (; !tsi_end_p (i); tsi_prev (&i)) | |
481 | { | |
482 | tree t = tsi_stmt (i); | |
483 | if (t == last) | |
484 | break; | |
485 | if (!check_constexpr_ctor_body_1 (last, t)) | |
486 | { | |
487 | ok = false; | |
488 | break; | |
489 | } | |
490 | } | |
491 | } | |
492 | else if (list != last | |
493 | && !check_constexpr_ctor_body_1 (last, list)) | |
494 | ok = false; | |
495 | if (!ok) | |
496 | { | |
497 | if (complain) | |
5967b28b | 498 | error ("%<constexpr%> constructor does not have empty body"); |
09b42213 | 499 | DECL_DECLARED_CONSTEXPR_P (current_function_decl) = false; |
500 | } | |
501 | return ok; | |
502 | } | |
503 | ||
504 | /* V is a vector of constructor elements built up for the base and member | |
505 | initializers of a constructor for TYPE. They need to be in increasing | |
506 | offset order, which they might not be yet if TYPE has a primary base | |
507 | which is not first in the base-clause or a vptr and at least one base | |
508 | all of which are non-primary. */ | |
509 | ||
510 | static vec<constructor_elt, va_gc> * | |
511 | sort_constexpr_mem_initializers (tree type, vec<constructor_elt, va_gc> *v) | |
512 | { | |
513 | tree pri = CLASSTYPE_PRIMARY_BINFO (type); | |
514 | tree field_type; | |
515 | unsigned i; | |
516 | constructor_elt *ce; | |
517 | ||
518 | if (pri) | |
519 | field_type = BINFO_TYPE (pri); | |
520 | else if (TYPE_CONTAINS_VPTR_P (type)) | |
521 | field_type = vtbl_ptr_type_node; | |
522 | else | |
523 | return v; | |
524 | ||
525 | /* Find the element for the primary base or vptr and move it to the | |
526 | beginning of the vec. */ | |
527 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
528 | if (TREE_TYPE (ce->index) == field_type) | |
529 | break; | |
530 | ||
531 | if (i > 0 && i < vec_safe_length (v)) | |
532 | { | |
533 | vec<constructor_elt, va_gc> &vref = *v; | |
534 | constructor_elt elt = vref[i]; | |
535 | for (; i > 0; --i) | |
536 | vref[i] = vref[i-1]; | |
537 | vref[0] = elt; | |
538 | } | |
539 | ||
540 | return v; | |
541 | } | |
542 | ||
543 | /* Build compile-time evalable representations of member-initializer list | |
544 | for a constexpr constructor. */ | |
545 | ||
546 | static tree | |
547 | build_constexpr_constructor_member_initializers (tree type, tree body) | |
548 | { | |
549 | vec<constructor_elt, va_gc> *vec = NULL; | |
550 | bool ok = true; | |
816919e1 | 551 | while (true) |
552 | switch (TREE_CODE (body)) | |
553 | { | |
554 | case MUST_NOT_THROW_EXPR: | |
555 | case EH_SPEC_BLOCK: | |
556 | body = TREE_OPERAND (body, 0); | |
557 | break; | |
558 | ||
559 | case STATEMENT_LIST: | |
560 | for (tree_stmt_iterator i = tsi_start (body); | |
561 | !tsi_end_p (i); tsi_next (&i)) | |
562 | { | |
563 | body = tsi_stmt (i); | |
564 | if (TREE_CODE (body) == BIND_EXPR) | |
565 | break; | |
566 | } | |
567 | break; | |
568 | ||
569 | case BIND_EXPR: | |
570 | body = BIND_EXPR_BODY (body); | |
571 | goto found; | |
572 | ||
573 | default: | |
574 | gcc_unreachable (); | |
8a36d0ec | 575 | } |
816919e1 | 576 | found: |
09b42213 | 577 | if (TREE_CODE (body) == CLEANUP_POINT_EXPR) |
578 | { | |
579 | body = TREE_OPERAND (body, 0); | |
580 | if (TREE_CODE (body) == EXPR_STMT) | |
581 | body = TREE_OPERAND (body, 0); | |
582 | if (TREE_CODE (body) == INIT_EXPR | |
583 | && (same_type_ignoring_top_level_qualifiers_p | |
584 | (TREE_TYPE (TREE_OPERAND (body, 0)), | |
585 | current_class_type))) | |
586 | { | |
587 | /* Trivial copy. */ | |
588 | return TREE_OPERAND (body, 1); | |
589 | } | |
590 | ok = build_data_member_initialization (body, &vec); | |
591 | } | |
592 | else if (TREE_CODE (body) == STATEMENT_LIST) | |
593 | { | |
594 | tree_stmt_iterator i; | |
595 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
596 | { | |
597 | ok = build_data_member_initialization (tsi_stmt (i), &vec); | |
598 | if (!ok) | |
599 | break; | |
600 | } | |
601 | } | |
602 | else if (TREE_CODE (body) == TRY_BLOCK) | |
603 | { | |
604 | error ("body of %<constexpr%> constructor cannot be " | |
605 | "a function-try-block"); | |
606 | return error_mark_node; | |
607 | } | |
608 | else if (EXPR_P (body)) | |
609 | ok = build_data_member_initialization (body, &vec); | |
610 | else | |
611 | gcc_assert (errorcount > 0); | |
612 | if (ok) | |
613 | { | |
614 | if (vec_safe_length (vec) > 0) | |
615 | { | |
616 | /* In a delegating constructor, return the target. */ | |
617 | constructor_elt *ce = &(*vec)[0]; | |
618 | if (ce->index == current_class_ptr) | |
619 | { | |
620 | body = ce->value; | |
621 | vec_free (vec); | |
622 | return body; | |
623 | } | |
624 | } | |
625 | vec = sort_constexpr_mem_initializers (type, vec); | |
626 | return build_constructor (type, vec); | |
627 | } | |
628 | else | |
629 | return error_mark_node; | |
630 | } | |
631 | ||
2fb20ba2 | 632 | /* We have an expression tree T that represents a call, either CALL_EXPR |
633 | or AGGR_INIT_EXPR. If the call is lexically to a named function, | |
634 | retrun the _DECL for that function. */ | |
635 | ||
636 | static tree | |
637 | get_function_named_in_call (tree t) | |
638 | { | |
639 | tree fun = cp_get_callee (t); | |
640 | if (fun && TREE_CODE (fun) == ADDR_EXPR | |
641 | && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL) | |
642 | fun = TREE_OPERAND (fun, 0); | |
643 | return fun; | |
644 | } | |
645 | ||
09b42213 | 646 | /* Subroutine of register_constexpr_fundef. BODY is the body of a function |
647 | declared to be constexpr, or a sub-statement thereof. Returns the | |
648 | return value if suitable, error_mark_node for a statement not allowed in | |
649 | a constexpr function, or NULL_TREE if no return value was found. */ | |
650 | ||
651 | static tree | |
652 | constexpr_fn_retval (tree body) | |
653 | { | |
654 | switch (TREE_CODE (body)) | |
655 | { | |
656 | case STATEMENT_LIST: | |
657 | { | |
658 | tree_stmt_iterator i; | |
659 | tree expr = NULL_TREE; | |
660 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
661 | { | |
662 | tree s = constexpr_fn_retval (tsi_stmt (i)); | |
663 | if (s == error_mark_node) | |
664 | return error_mark_node; | |
665 | else if (s == NULL_TREE) | |
666 | /* Keep iterating. */; | |
667 | else if (expr) | |
668 | /* Multiple return statements. */ | |
669 | return error_mark_node; | |
670 | else | |
671 | expr = s; | |
672 | } | |
673 | return expr; | |
674 | } | |
675 | ||
676 | case RETURN_EXPR: | |
677 | return break_out_target_exprs (TREE_OPERAND (body, 0)); | |
678 | ||
679 | case DECL_EXPR: | |
394aed6a | 680 | { |
681 | tree decl = DECL_EXPR_DECL (body); | |
682 | if (TREE_CODE (decl) == USING_DECL | |
683 | /* Accept __func__, __FUNCTION__, and __PRETTY_FUNCTION__. */ | |
684 | || DECL_ARTIFICIAL (decl)) | |
685 | return NULL_TREE; | |
686 | return error_mark_node; | |
687 | } | |
09b42213 | 688 | |
689 | case CLEANUP_POINT_EXPR: | |
690 | return constexpr_fn_retval (TREE_OPERAND (body, 0)); | |
691 | ||
692 | case BIND_EXPR: | |
693 | if (!check_constexpr_bind_expr_vars (body)) | |
694 | return error_mark_node; | |
695 | return constexpr_fn_retval (BIND_EXPR_BODY (body)); | |
696 | ||
697 | case USING_STMT: | |
90567983 | 698 | case DEBUG_BEGIN_STMT: |
09b42213 | 699 | return NULL_TREE; |
700 | ||
2fb20ba2 | 701 | case CALL_EXPR: |
702 | { | |
703 | tree fun = get_function_named_in_call (body); | |
704 | if (fun != NULL_TREE | |
705 | && DECL_FUNCTION_CODE (fun) == BUILT_IN_UNREACHABLE) | |
706 | return NULL_TREE; | |
707 | } | |
708 | /* Fallthru. */ | |
709 | ||
09b42213 | 710 | default: |
711 | return error_mark_node; | |
712 | } | |
713 | } | |
714 | ||
715 | /* Subroutine of register_constexpr_fundef. BODY is the DECL_SAVED_TREE of | |
716 | FUN; do the necessary transformations to turn it into a single expression | |
717 | that we can store in the hash table. */ | |
718 | ||
719 | static tree | |
720 | massage_constexpr_body (tree fun, tree body) | |
721 | { | |
722 | if (DECL_CONSTRUCTOR_P (fun)) | |
723 | body = build_constexpr_constructor_member_initializers | |
724 | (DECL_CONTEXT (fun), body); | |
9c96033c | 725 | else if (cxx_dialect < cxx14) |
09b42213 | 726 | { |
727 | if (TREE_CODE (body) == EH_SPEC_BLOCK) | |
728 | body = EH_SPEC_STMTS (body); | |
729 | if (TREE_CODE (body) == MUST_NOT_THROW_EXPR) | |
730 | body = TREE_OPERAND (body, 0); | |
731 | body = constexpr_fn_retval (body); | |
732 | } | |
733 | return body; | |
734 | } | |
735 | ||
2f4cab3c | 736 | /* CTYPE is a type constructed from BODY. Return true if some |
737 | bases/fields are uninitialized, and complain if COMPLAIN. */ | |
09b42213 | 738 | |
739 | static bool | |
2f4cab3c | 740 | cx_check_missing_mem_inits (tree ctype, tree body, bool complain) |
09b42213 | 741 | { |
2f4cab3c | 742 | unsigned nelts = 0; |
743 | ||
744 | if (body) | |
745 | { | |
746 | if (TREE_CODE (body) != CONSTRUCTOR) | |
747 | return false; | |
748 | nelts = CONSTRUCTOR_NELTS (body); | |
749 | } | |
750 | tree field = TYPE_FIELDS (ctype); | |
09b42213 | 751 | |
752 | if (TREE_CODE (ctype) == UNION_TYPE) | |
753 | { | |
754 | if (nelts == 0 && next_initializable_field (field)) | |
755 | { | |
756 | if (complain) | |
757 | error ("%<constexpr%> constructor for union %qT must " | |
758 | "initialize exactly one non-static data member", ctype); | |
759 | return true; | |
760 | } | |
761 | return false; | |
762 | } | |
763 | ||
2f4cab3c | 764 | /* Iterate over the CONSTRUCTOR, checking any missing fields don't |
765 | need an explicit initialization. */ | |
766 | bool bad = false; | |
767 | for (unsigned i = 0; i <= nelts; ++i) | |
09b42213 | 768 | { |
2f4cab3c | 769 | tree index = NULL_TREE; |
770 | if (i < nelts) | |
09b42213 | 771 | { |
772 | index = CONSTRUCTOR_ELT (body, i)->index; | |
773 | /* Skip base and vtable inits. */ | |
774 | if (TREE_CODE (index) != FIELD_DECL | |
775 | || DECL_ARTIFICIAL (index)) | |
776 | continue; | |
777 | } | |
2f4cab3c | 778 | |
09b42213 | 779 | for (; field != index; field = DECL_CHAIN (field)) |
780 | { | |
781 | tree ftype; | |
2f4cab3c | 782 | if (TREE_CODE (field) != FIELD_DECL) |
783 | continue; | |
784 | if (DECL_C_BIT_FIELD (field) && !DECL_NAME (field)) | |
09b42213 | 785 | continue; |
2f4cab3c | 786 | if (DECL_ARTIFICIAL (field)) |
787 | continue; | |
788 | if (ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
789 | { | |
790 | /* Recurse to check the anonummous aggregate member. */ | |
791 | bad |= cx_check_missing_mem_inits | |
792 | (TREE_TYPE (field), NULL_TREE, complain); | |
793 | if (bad && !complain) | |
794 | return true; | |
795 | continue; | |
796 | } | |
09b42213 | 797 | ftype = strip_array_types (TREE_TYPE (field)); |
798 | if (type_has_constexpr_default_constructor (ftype)) | |
799 | { | |
800 | /* It's OK to skip a member with a trivial constexpr ctor. | |
801 | A constexpr ctor that isn't trivial should have been | |
802 | added in by now. */ | |
803 | gcc_checking_assert (!TYPE_HAS_COMPLEX_DFLT (ftype) | |
804 | || errorcount != 0); | |
805 | continue; | |
806 | } | |
807 | if (!complain) | |
808 | return true; | |
859e2c29 | 809 | error ("member %qD must be initialized by mem-initializer " |
810 | "in %<constexpr%> constructor", field); | |
811 | inform (DECL_SOURCE_LOCATION (field), "declared here"); | |
09b42213 | 812 | bad = true; |
813 | } | |
814 | if (field == NULL_TREE) | |
815 | break; | |
2f4cab3c | 816 | |
817 | if (ANON_AGGR_TYPE_P (TREE_TYPE (index))) | |
818 | { | |
819 | /* Check the anonymous aggregate initializer is valid. */ | |
820 | bad |= cx_check_missing_mem_inits | |
821 | (TREE_TYPE (index), CONSTRUCTOR_ELT (body, i)->value, complain); | |
822 | if (bad && !complain) | |
823 | return true; | |
824 | } | |
09b42213 | 825 | field = DECL_CHAIN (field); |
826 | } | |
827 | ||
828 | return bad; | |
829 | } | |
830 | ||
831 | /* We are processing the definition of the constexpr function FUN. | |
832 | Check that its BODY fulfills the propriate requirements and | |
833 | enter it in the constexpr function definition table. | |
834 | For constructor BODY is actually the TREE_LIST of the | |
835 | member-initializer list. */ | |
836 | ||
837 | tree | |
838 | register_constexpr_fundef (tree fun, tree body) | |
839 | { | |
840 | constexpr_fundef entry; | |
841 | constexpr_fundef **slot; | |
842 | ||
843 | if (!is_valid_constexpr_fn (fun, !DECL_GENERATED_P (fun))) | |
844 | return NULL; | |
845 | ||
6a385150 | 846 | tree massaged = massage_constexpr_body (fun, body); |
847 | if (massaged == NULL_TREE || massaged == error_mark_node) | |
09b42213 | 848 | { |
849 | if (!DECL_CONSTRUCTOR_P (fun)) | |
5967b28b | 850 | error ("body of %<constexpr%> function %qD not a return-statement", |
851 | fun); | |
09b42213 | 852 | return NULL; |
853 | } | |
854 | ||
6a385150 | 855 | if (!potential_rvalue_constant_expression (massaged)) |
09b42213 | 856 | { |
857 | if (!DECL_GENERATED_P (fun)) | |
6a385150 | 858 | require_potential_rvalue_constant_expression (massaged); |
09b42213 | 859 | return NULL; |
860 | } | |
861 | ||
862 | if (DECL_CONSTRUCTOR_P (fun) | |
2f4cab3c | 863 | && cx_check_missing_mem_inits (DECL_CONTEXT (fun), |
864 | massaged, !DECL_GENERATED_P (fun))) | |
09b42213 | 865 | return NULL; |
866 | ||
867 | /* Create the constexpr function table if necessary. */ | |
868 | if (constexpr_fundef_table == NULL) | |
869 | constexpr_fundef_table | |
870 | = hash_table<constexpr_fundef_hasher>::create_ggc (101); | |
871 | ||
872 | entry.decl = fun; | |
873 | entry.body = body; | |
874 | slot = constexpr_fundef_table->find_slot (&entry, INSERT); | |
875 | ||
876 | gcc_assert (*slot == NULL); | |
877 | *slot = ggc_alloc<constexpr_fundef> (); | |
878 | **slot = entry; | |
879 | ||
880 | return fun; | |
881 | } | |
882 | ||
883 | /* FUN is a non-constexpr function called in a context that requires a | |
884 | constant expression. If it comes from a constexpr template, explain why | |
885 | the instantiation isn't constexpr. */ | |
886 | ||
887 | void | |
888 | explain_invalid_constexpr_fn (tree fun) | |
889 | { | |
890 | static hash_set<tree> *diagnosed; | |
891 | tree body; | |
892 | location_t save_loc; | |
33603066 | 893 | /* Only diagnose defaulted functions, lambdas, or instantiations. */ |
09b42213 | 894 | if (!DECL_DEFAULTED_FN (fun) |
33603066 | 895 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) |
09b42213 | 896 | && !is_instantiation_of_constexpr (fun)) |
897 | return; | |
898 | if (diagnosed == NULL) | |
899 | diagnosed = new hash_set<tree>; | |
900 | if (diagnosed->add (fun)) | |
901 | /* Already explained. */ | |
902 | return; | |
903 | ||
904 | save_loc = input_location; | |
33603066 | 905 | if (!lambda_static_thunk_p (fun)) |
906 | { | |
907 | /* Diagnostics should completely ignore the static thunk, so leave | |
908 | input_location set to our caller's location. */ | |
909 | input_location = DECL_SOURCE_LOCATION (fun); | |
910 | inform (input_location, | |
5967b28b | 911 | "%qD is not usable as a %<constexpr%> function because:", fun); |
33603066 | 912 | } |
09b42213 | 913 | /* First check the declaration. */ |
914 | if (is_valid_constexpr_fn (fun, true)) | |
915 | { | |
916 | /* Then if it's OK, the body. */ | |
33603066 | 917 | if (!DECL_DECLARED_CONSTEXPR_P (fun) |
918 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun))) | |
09b42213 | 919 | explain_implicit_non_constexpr (fun); |
920 | else | |
921 | { | |
922 | body = massage_constexpr_body (fun, DECL_SAVED_TREE (fun)); | |
923 | require_potential_rvalue_constant_expression (body); | |
924 | if (DECL_CONSTRUCTOR_P (fun)) | |
2f4cab3c | 925 | cx_check_missing_mem_inits (DECL_CONTEXT (fun), body, true); |
09b42213 | 926 | } |
927 | } | |
928 | input_location = save_loc; | |
929 | } | |
930 | ||
931 | /* Objects of this type represent calls to constexpr functions | |
932 | along with the bindings of parameters to their arguments, for | |
933 | the purpose of compile time evaluation. */ | |
934 | ||
935 | struct GTY((for_user)) constexpr_call { | |
936 | /* Description of the constexpr function definition. */ | |
937 | constexpr_fundef *fundef; | |
938 | /* Parameter bindings environment. A TREE_LIST where each TREE_PURPOSE | |
939 | is a parameter _DECL and the TREE_VALUE is the value of the parameter. | |
940 | Note: This arrangement is made to accommodate the use of | |
941 | iterative_hash_template_arg (see pt.c). If you change this | |
942 | representation, also change the hash calculation in | |
943 | cxx_eval_call_expression. */ | |
944 | tree bindings; | |
945 | /* Result of the call. | |
946 | NULL means the call is being evaluated. | |
947 | error_mark_node means that the evaluation was erroneous; | |
948 | otherwise, the actuall value of the call. */ | |
949 | tree result; | |
950 | /* The hash of this call; we remember it here to avoid having to | |
951 | recalculate it when expanding the hash table. */ | |
952 | hashval_t hash; | |
953 | }; | |
954 | ||
b594087e | 955 | struct constexpr_call_hasher : ggc_ptr_hash<constexpr_call> |
09b42213 | 956 | { |
957 | static hashval_t hash (constexpr_call *); | |
958 | static bool equal (constexpr_call *, constexpr_call *); | |
cf72f34d | 959 | }; |
960 | ||
2a2770c6 | 961 | enum constexpr_switch_state { |
962 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
963 | and default: label for that switch has not been seen yet. */ | |
964 | css_default_not_seen, | |
965 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
966 | and default: label for that switch has been seen already. */ | |
967 | css_default_seen, | |
968 | /* Used when processing a switch for the second time by | |
969 | cxx_eval_switch_expr, where default: label should match. */ | |
970 | css_default_processing | |
971 | }; | |
972 | ||
cf72f34d | 973 | /* The constexpr expansion context. CALL is the current function |
974 | expansion, CTOR is the current aggregate initializer, OBJECT is the | |
975 | object being initialized by CTOR, either a VAR_DECL or a _REF. VALUES | |
976 | is a map of values of variables initialized within the expression. */ | |
977 | ||
978 | struct constexpr_ctx { | |
f9885b8a | 979 | /* The innermost call we're evaluating. */ |
cf72f34d | 980 | constexpr_call *call; |
f9885b8a | 981 | /* Values for any temporaries or local variables within the |
982 | constant-expression. */ | |
cf72f34d | 983 | hash_map<tree,tree> *values; |
2631cb67 | 984 | /* SAVE_EXPRs that we've seen within the current LOOP_EXPR. NULL if we |
985 | aren't inside a loop. */ | |
986 | hash_set<tree> *save_exprs; | |
f9885b8a | 987 | /* The CONSTRUCTOR we're currently building up for an aggregate |
988 | initializer. */ | |
cf72f34d | 989 | tree ctor; |
f9885b8a | 990 | /* The object we're building the CONSTRUCTOR for. */ |
cf72f34d | 991 | tree object; |
2a2770c6 | 992 | /* If inside SWITCH_EXPR. */ |
993 | constexpr_switch_state *css_state; | |
f9885b8a | 994 | /* Whether we should error on a non-constant expression or fail quietly. */ |
f83e6885 | 995 | bool quiet; |
f9885b8a | 996 | /* Whether we are strictly conforming to constant expression rules or |
997 | trying harder to get a constant value. */ | |
2055d27a | 998 | bool strict; |
cf72f34d | 999 | }; |
09b42213 | 1000 | |
1001 | /* A table of all constexpr calls that have been evaluated by the | |
1002 | compiler in this translation unit. */ | |
1003 | ||
a050099a | 1004 | static GTY (()) hash_table<constexpr_call_hasher> *constexpr_call_table; |
09b42213 | 1005 | |
cf72f34d | 1006 | static tree cxx_eval_constant_expression (const constexpr_ctx *, tree, |
b2a43197 | 1007 | bool, bool *, bool *, tree * = NULL); |
09b42213 | 1008 | |
1009 | /* Compute a hash value for a constexpr call representation. */ | |
1010 | ||
1011 | inline hashval_t | |
1012 | constexpr_call_hasher::hash (constexpr_call *info) | |
1013 | { | |
1014 | return info->hash; | |
1015 | } | |
1016 | ||
1017 | /* Return true if the objects pointed to by P and Q represent calls | |
1018 | to the same constexpr function with the same arguments. | |
1019 | Otherwise, return false. */ | |
1020 | ||
1021 | bool | |
1022 | constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs) | |
1023 | { | |
1024 | tree lhs_bindings; | |
1025 | tree rhs_bindings; | |
1026 | if (lhs == rhs) | |
1027 | return 1; | |
1028 | if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef)) | |
1029 | return 0; | |
1030 | lhs_bindings = lhs->bindings; | |
1031 | rhs_bindings = rhs->bindings; | |
1032 | while (lhs_bindings != NULL && rhs_bindings != NULL) | |
1033 | { | |
1034 | tree lhs_arg = TREE_VALUE (lhs_bindings); | |
1035 | tree rhs_arg = TREE_VALUE (rhs_bindings); | |
1036 | gcc_assert (TREE_TYPE (lhs_arg) == TREE_TYPE (rhs_arg)); | |
1037 | if (!cp_tree_equal (lhs_arg, rhs_arg)) | |
1038 | return 0; | |
1039 | lhs_bindings = TREE_CHAIN (lhs_bindings); | |
1040 | rhs_bindings = TREE_CHAIN (rhs_bindings); | |
1041 | } | |
1042 | return lhs_bindings == rhs_bindings; | |
1043 | } | |
1044 | ||
1045 | /* Initialize the constexpr call table, if needed. */ | |
1046 | ||
1047 | static void | |
1048 | maybe_initialize_constexpr_call_table (void) | |
1049 | { | |
1050 | if (constexpr_call_table == NULL) | |
1051 | constexpr_call_table = hash_table<constexpr_call_hasher>::create_ggc (101); | |
1052 | } | |
1053 | ||
4f7ebe46 | 1054 | /* During constexpr CALL_EXPR evaluation, to avoid issues with sharing when |
1055 | a function happens to get called recursively, we unshare the callee | |
1056 | function's body and evaluate this unshared copy instead of evaluating the | |
1057 | original body. | |
1058 | ||
1059 | FUNDEF_COPIES_TABLE is a per-function freelist of these unshared function | |
1060 | copies. The underlying data structure of FUNDEF_COPIES_TABLE is a hash_map | |
a050099a | 1061 | that's keyed off of the original FUNCTION_DECL and whose value is a |
1062 | TREE_LIST of this function's unused copies awaiting reuse. | |
4f7ebe46 | 1063 | |
a050099a | 1064 | This is not GC-deletable to avoid GC affecting UID generation. */ |
4f7ebe46 | 1065 | |
a050099a | 1066 | static GTY(()) hash_map<tree, tree> *fundef_copies_table; |
4f7ebe46 | 1067 | |
1068 | /* Initialize FUNDEF_COPIES_TABLE if it's not initialized. */ | |
1069 | ||
1070 | static void | |
1071 | maybe_initialize_fundef_copies_table () | |
1072 | { | |
a050099a | 1073 | if (fundef_copies_table == NULL) |
1074 | fundef_copies_table = hash_map<tree,tree>::create_ggc (101); | |
4f7ebe46 | 1075 | } |
1076 | ||
1077 | /* Reuse a copy or create a new unshared copy of the function FUN. | |
886d5463 | 1078 | Return this copy. We use a TREE_LIST whose PURPOSE is body, VALUE |
1079 | is parms, TYPE is result. */ | |
4f7ebe46 | 1080 | |
a050099a | 1081 | static tree |
4f7ebe46 | 1082 | get_fundef_copy (tree fun) |
1083 | { | |
1084 | maybe_initialize_fundef_copies_table (); | |
1085 | ||
a050099a | 1086 | tree copy; |
886d5463 | 1087 | bool existed; |
1088 | tree *slot = &fundef_copies_table->get_or_insert (fun, &existed); | |
1089 | ||
1090 | if (!existed) | |
4f7ebe46 | 1091 | { |
886d5463 | 1092 | /* There is no cached function available, or in use. We can use |
1093 | the function directly. That the slot is now created records | |
1094 | that this function is now in use. */ | |
1095 | copy = build_tree_list (DECL_SAVED_TREE (fun), DECL_ARGUMENTS (fun)); | |
1096 | TREE_TYPE (copy) = DECL_RESULT (fun); | |
1097 | } | |
1098 | else if (*slot == NULL_TREE) | |
1099 | { | |
1100 | /* We've already used the function itself, so make a copy. */ | |
a050099a | 1101 | copy = build_tree_list (NULL, NULL); |
a050099a | 1102 | TREE_PURPOSE (copy) = copy_fn (fun, TREE_VALUE (copy), TREE_TYPE (copy)); |
4f7ebe46 | 1103 | } |
1104 | else | |
1105 | { | |
886d5463 | 1106 | /* We have a cached function available. */ |
4f7ebe46 | 1107 | copy = *slot; |
a050099a | 1108 | *slot = TREE_CHAIN (copy); |
4f7ebe46 | 1109 | } |
1110 | ||
1111 | return copy; | |
1112 | } | |
1113 | ||
886d5463 | 1114 | /* Save the copy COPY of function FUN for later reuse by |
1115 | get_fundef_copy(). By construction, there will always be an entry | |
1116 | to find. */ | |
4f7ebe46 | 1117 | |
1118 | static void | |
a050099a | 1119 | save_fundef_copy (tree fun, tree copy) |
4f7ebe46 | 1120 | { |
886d5463 | 1121 | tree *slot = fundef_copies_table->get (fun); |
a050099a | 1122 | TREE_CHAIN (copy) = *slot; |
4f7ebe46 | 1123 | *slot = copy; |
1124 | } | |
1125 | ||
09b42213 | 1126 | /* We have an expression tree T that represents a call, either CALL_EXPR |
1127 | or AGGR_INIT_EXPR. Return the Nth argument. */ | |
1128 | ||
1129 | static inline tree | |
1130 | get_nth_callarg (tree t, int n) | |
1131 | { | |
1132 | switch (TREE_CODE (t)) | |
1133 | { | |
1134 | case CALL_EXPR: | |
1135 | return CALL_EXPR_ARG (t, n); | |
1136 | ||
1137 | case AGGR_INIT_EXPR: | |
1138 | return AGGR_INIT_EXPR_ARG (t, n); | |
1139 | ||
1140 | default: | |
1141 | gcc_unreachable (); | |
1142 | return NULL; | |
1143 | } | |
1144 | } | |
1145 | ||
09b42213 | 1146 | /* Attempt to evaluate T which represents a call to a builtin function. |
1147 | We assume here that all builtin functions evaluate to scalar types | |
1148 | represented by _CST nodes. */ | |
1149 | ||
1150 | static tree | |
f1c6af10 | 1151 | cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, |
1227ba74 | 1152 | bool lval, |
09b42213 | 1153 | bool *non_constant_p, bool *overflow_p) |
1154 | { | |
1155 | const int nargs = call_expr_nargs (t); | |
1156 | tree *args = (tree *) alloca (nargs * sizeof (tree)); | |
1157 | tree new_call; | |
1158 | int i; | |
f1c6af10 | 1159 | |
1160 | /* Don't fold __builtin_constant_p within a constexpr function. */ | |
efe6a40a | 1161 | bool bi_const_p = (DECL_FUNCTION_CODE (fun) == BUILT_IN_CONSTANT_P); |
1162 | ||
1163 | if (bi_const_p | |
f1c6af10 | 1164 | && current_function_decl |
1165 | && DECL_DECLARED_CONSTEXPR_P (current_function_decl)) | |
09b42213 | 1166 | { |
f1c6af10 | 1167 | *non_constant_p = true; |
1168 | return t; | |
09b42213 | 1169 | } |
f1c6af10 | 1170 | |
1171 | /* Be permissive for arguments to built-ins; __builtin_constant_p should | |
1172 | return constant false for a non-constant argument. */ | |
1173 | constexpr_ctx new_ctx = *ctx; | |
1174 | new_ctx.quiet = true; | |
1175 | bool dummy1 = false, dummy2 = false; | |
1176 | for (i = 0; i < nargs; ++i) | |
efe6a40a | 1177 | { |
1178 | args[i] = cxx_eval_constant_expression (&new_ctx, CALL_EXPR_ARG (t, i), | |
051eb924 | 1179 | false, &dummy1, &dummy2); |
efe6a40a | 1180 | if (bi_const_p) |
1181 | /* For __built_in_constant_p, fold all expressions with constant values | |
1182 | even if they aren't C++ constant-expressions. */ | |
1183 | args[i] = cp_fully_fold (args[i]); | |
1184 | } | |
f1c6af10 | 1185 | |
1186 | bool save_ffbcp = force_folding_builtin_constant_p; | |
1187 | force_folding_builtin_constant_p = true; | |
051eb924 | 1188 | new_call = fold_builtin_call_array (EXPR_LOCATION (t), TREE_TYPE (t), |
1189 | CALL_EXPR_FN (t), nargs, args); | |
f1c6af10 | 1190 | force_folding_builtin_constant_p = save_ffbcp; |
051eb924 | 1191 | if (new_call == NULL) |
1192 | { | |
1193 | if (!*non_constant_p && !ctx->quiet) | |
1194 | { | |
2fb20ba2 | 1195 | /* Do not allow__builtin_unreachable in constexpr function. |
1196 | The __builtin_unreachable call with BUILTINS_LOCATION | |
1197 | comes from cp_maybe_instrument_return. */ | |
1198 | if (DECL_FUNCTION_CODE (fun) == BUILT_IN_UNREACHABLE | |
1199 | && EXPR_LOCATION (t) == BUILTINS_LOCATION) | |
5967b28b | 1200 | error ("%<constexpr%> call flows off the end of the function"); |
2fb20ba2 | 1201 | else |
1202 | { | |
1203 | new_call = build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t), | |
1204 | CALL_EXPR_FN (t), nargs, args); | |
1205 | error ("%q+E is not a constant expression", new_call); | |
1206 | } | |
051eb924 | 1207 | } |
1208 | *non_constant_p = true; | |
1209 | return t; | |
1210 | } | |
1211 | ||
7e1f8be4 | 1212 | if (!is_constant_expression (new_call)) |
051eb924 | 1213 | { |
1214 | if (!*non_constant_p && !ctx->quiet) | |
1215 | error ("%q+E is not a constant expression", new_call); | |
1216 | *non_constant_p = true; | |
1217 | return t; | |
1218 | } | |
1219 | ||
1220 | return cxx_eval_constant_expression (&new_ctx, new_call, lval, | |
1221 | non_constant_p, overflow_p); | |
09b42213 | 1222 | } |
1223 | ||
1224 | /* TEMP is the constant value of a temporary object of type TYPE. Adjust | |
1225 | the type of the value to match. */ | |
1226 | ||
1227 | static tree | |
1228 | adjust_temp_type (tree type, tree temp) | |
1229 | { | |
1230 | if (TREE_TYPE (temp) == type) | |
1231 | return temp; | |
1232 | /* Avoid wrapping an aggregate value in a NOP_EXPR. */ | |
1233 | if (TREE_CODE (temp) == CONSTRUCTOR) | |
1234 | return build_constructor (type, CONSTRUCTOR_ELTS (temp)); | |
1235 | gcc_assert (scalarish_type_p (type)); | |
1236 | return cp_fold_convert (type, temp); | |
1237 | } | |
1238 | ||
e283bb4f | 1239 | /* Callback for walk_tree used by unshare_constructor. */ |
1240 | ||
1241 | static tree | |
1242 | find_constructor (tree *tp, int *walk_subtrees, void *) | |
1243 | { | |
1244 | if (TYPE_P (*tp)) | |
1245 | *walk_subtrees = 0; | |
1246 | if (TREE_CODE (*tp) == CONSTRUCTOR) | |
1247 | return *tp; | |
1248 | return NULL_TREE; | |
1249 | } | |
1250 | ||
1251 | /* If T is a CONSTRUCTOR or an expression that has a CONSTRUCTOR node as a | |
1252 | subexpression, return an unshared copy of T. Otherwise return T. */ | |
1253 | ||
1254 | static tree | |
1255 | unshare_constructor (tree t) | |
1256 | { | |
1257 | tree ctor = walk_tree (&t, find_constructor, NULL, NULL); | |
1258 | if (ctor != NULL_TREE) | |
1259 | return unshare_expr (t); | |
1260 | return t; | |
1261 | } | |
1262 | ||
09b42213 | 1263 | /* Subroutine of cxx_eval_call_expression. |
1264 | We are processing a call expression (either CALL_EXPR or | |
cf72f34d | 1265 | AGGR_INIT_EXPR) in the context of CTX. Evaluate |
09b42213 | 1266 | all arguments and bind their values to correspondings |
1267 | parameters, making up the NEW_CALL context. */ | |
1268 | ||
1269 | static void | |
cf72f34d | 1270 | cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, |
09b42213 | 1271 | constexpr_call *new_call, |
c8f6aeb1 | 1272 | bool *non_constant_p, bool *overflow_p, |
1273 | bool *non_constant_args) | |
09b42213 | 1274 | { |
1275 | const int nargs = call_expr_nargs (t); | |
1276 | tree fun = new_call->fundef->decl; | |
1277 | tree parms = DECL_ARGUMENTS (fun); | |
1278 | int i; | |
9c96033c | 1279 | tree *p = &new_call->bindings; |
09b42213 | 1280 | for (i = 0; i < nargs; ++i) |
1281 | { | |
1282 | tree x, arg; | |
1283 | tree type = parms ? TREE_TYPE (parms) : void_type_node; | |
09b42213 | 1284 | x = get_nth_callarg (t, i); |
cf72f34d | 1285 | /* For member function, the first argument is a pointer to the implied |
1286 | object. For a constructor, it might still be a dummy object, in | |
9c96033c | 1287 | which case we get the real argument from ctx. */ |
cf72f34d | 1288 | if (i == 0 && DECL_CONSTRUCTOR_P (fun) |
1289 | && is_dummy_object (x)) | |
1290 | { | |
1291 | x = ctx->object; | |
c017458d | 1292 | x = build_address (x); |
cf72f34d | 1293 | } |
1227ba74 | 1294 | bool lval = false; |
1227ba74 | 1295 | arg = cxx_eval_constant_expression (ctx, x, lval, |
b2a43197 | 1296 | non_constant_p, overflow_p); |
09b42213 | 1297 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 1298 | if (*non_constant_p && ctx->quiet) |
09b42213 | 1299 | return; |
1300 | /* Just discard ellipsis args after checking their constantitude. */ | |
1301 | if (!parms) | |
1302 | continue; | |
2ba934c7 | 1303 | |
1304 | if (!*non_constant_p) | |
1305 | { | |
1306 | /* Make sure the binding has the same type as the parm. But | |
1307 | only for constant args. */ | |
1308 | if (TREE_CODE (type) != REFERENCE_TYPE) | |
1309 | arg = adjust_temp_type (type, arg); | |
1310 | if (!TREE_CONSTANT (arg)) | |
1311 | *non_constant_args = true; | |
1312 | *p = build_tree_list (parms, arg); | |
1313 | p = &TREE_CHAIN (*p); | |
1314 | } | |
09b42213 | 1315 | parms = TREE_CHAIN (parms); |
1316 | } | |
1317 | } | |
1318 | ||
1319 | /* Variables and functions to manage constexpr call expansion context. | |
1320 | These do not need to be marked for PCH or GC. */ | |
1321 | ||
1322 | /* FIXME remember and print actual constant arguments. */ | |
16fb756f | 1323 | static vec<tree> call_stack; |
09b42213 | 1324 | static int call_stack_tick; |
1325 | static int last_cx_error_tick; | |
1326 | ||
1327 | static bool | |
1328 | push_cx_call_context (tree call) | |
1329 | { | |
1330 | ++call_stack_tick; | |
1331 | if (!EXPR_HAS_LOCATION (call)) | |
1332 | SET_EXPR_LOCATION (call, input_location); | |
1333 | call_stack.safe_push (call); | |
1334 | if (call_stack.length () > (unsigned) max_constexpr_depth) | |
1335 | return false; | |
1336 | return true; | |
1337 | } | |
1338 | ||
1339 | static void | |
1340 | pop_cx_call_context (void) | |
1341 | { | |
1342 | ++call_stack_tick; | |
1343 | call_stack.pop (); | |
1344 | } | |
1345 | ||
1346 | vec<tree> | |
1347 | cx_error_context (void) | |
1348 | { | |
1349 | vec<tree> r = vNULL; | |
1350 | if (call_stack_tick != last_cx_error_tick | |
1351 | && !call_stack.is_empty ()) | |
1352 | r = call_stack; | |
1353 | last_cx_error_tick = call_stack_tick; | |
1354 | return r; | |
1355 | } | |
1356 | ||
732905bb | 1357 | /* Evaluate a call T to a GCC internal function when possible and return |
1358 | the evaluated result or, under the control of CTX, give an error, set | |
1359 | NON_CONSTANT_P, and return the unevaluated call T otherwise. */ | |
1360 | ||
1361 | static tree | |
1362 | cxx_eval_internal_function (const constexpr_ctx *ctx, tree t, | |
1363 | bool lval, | |
1364 | bool *non_constant_p, bool *overflow_p) | |
1365 | { | |
1366 | enum tree_code opcode = ERROR_MARK; | |
1367 | ||
1368 | switch (CALL_EXPR_IFN (t)) | |
1369 | { | |
1370 | case IFN_UBSAN_NULL: | |
1371 | case IFN_UBSAN_BOUNDS: | |
1372 | case IFN_UBSAN_VPTR: | |
3c77f69c | 1373 | case IFN_FALLTHROUGH: |
732905bb | 1374 | return void_node; |
1375 | ||
1376 | case IFN_ADD_OVERFLOW: | |
1377 | opcode = PLUS_EXPR; | |
1378 | break; | |
1379 | case IFN_SUB_OVERFLOW: | |
1380 | opcode = MINUS_EXPR; | |
1381 | break; | |
1382 | case IFN_MUL_OVERFLOW: | |
1383 | opcode = MULT_EXPR; | |
1384 | break; | |
1385 | ||
6e1b2ffb | 1386 | case IFN_LAUNDER: |
1387 | return cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), | |
1388 | false, non_constant_p, overflow_p); | |
1389 | ||
732905bb | 1390 | default: |
1391 | if (!ctx->quiet) | |
1392 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
1393 | "call to internal function %qE", t); | |
1394 | *non_constant_p = true; | |
1395 | return t; | |
1396 | } | |
1397 | ||
1398 | /* Evaluate constant arguments using OPCODE and return a complex | |
1399 | number containing the result and the overflow bit. */ | |
1400 | tree arg0 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), lval, | |
1401 | non_constant_p, overflow_p); | |
1402 | tree arg1 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 1), lval, | |
1403 | non_constant_p, overflow_p); | |
1404 | ||
1405 | if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) | |
1406 | { | |
1407 | location_t loc = EXPR_LOC_OR_LOC (t, input_location); | |
1408 | tree type = TREE_TYPE (TREE_TYPE (t)); | |
1409 | tree result = fold_binary_loc (loc, opcode, type, | |
1410 | fold_convert_loc (loc, type, arg0), | |
1411 | fold_convert_loc (loc, type, arg1)); | |
1412 | tree ovf | |
1413 | = build_int_cst (type, arith_overflowed_p (opcode, type, arg0, arg1)); | |
1414 | /* Reset TREE_OVERFLOW to avoid warnings for the overflow. */ | |
1415 | if (TREE_OVERFLOW (result)) | |
1416 | TREE_OVERFLOW (result) = 0; | |
1417 | ||
1418 | return build_complex (TREE_TYPE (t), result, ovf); | |
1419 | } | |
1420 | ||
1421 | *non_constant_p = true; | |
1422 | return t; | |
1423 | } | |
1424 | ||
79cdb4f5 | 1425 | /* Clean CONSTRUCTOR_NO_IMPLICIT_ZERO from CTOR and its sub-aggregates. */ |
1426 | ||
1427 | static void | |
1428 | clear_no_implicit_zero (tree ctor) | |
1429 | { | |
1430 | if (CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor)) | |
1431 | { | |
1432 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor) = false; | |
1433 | tree elt; unsigned HOST_WIDE_INT idx; | |
1434 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (ctor), idx, elt) | |
1435 | if (TREE_CODE (elt) == CONSTRUCTOR) | |
1436 | clear_no_implicit_zero (elt); | |
1437 | } | |
1438 | } | |
1439 | ||
09b42213 | 1440 | /* Subroutine of cxx_eval_constant_expression. |
1441 | Evaluate the call expression tree T in the context of OLD_CALL expression | |
1442 | evaluation. */ | |
1443 | ||
1444 | static tree | |
cf72f34d | 1445 | cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1446 | bool lval, |
09b42213 | 1447 | bool *non_constant_p, bool *overflow_p) |
1448 | { | |
1449 | location_t loc = EXPR_LOC_OR_LOC (t, input_location); | |
1450 | tree fun = get_function_named_in_call (t); | |
09b42213 | 1451 | constexpr_call new_call = { NULL, NULL, NULL, 0 }; |
09b42213 | 1452 | bool depth_ok; |
1453 | ||
6b71bdb4 | 1454 | if (fun == NULL_TREE) |
732905bb | 1455 | return cxx_eval_internal_function (ctx, t, lval, |
1456 | non_constant_p, overflow_p); | |
6b71bdb4 | 1457 | |
09b42213 | 1458 | if (TREE_CODE (fun) != FUNCTION_DECL) |
1459 | { | |
1460 | /* Might be a constexpr function pointer. */ | |
f83e6885 | 1461 | fun = cxx_eval_constant_expression (ctx, fun, |
1227ba74 | 1462 | /*lval*/false, non_constant_p, |
b2a43197 | 1463 | overflow_p); |
09b42213 | 1464 | STRIP_NOPS (fun); |
1465 | if (TREE_CODE (fun) == ADDR_EXPR) | |
1466 | fun = TREE_OPERAND (fun, 0); | |
1467 | } | |
1468 | if (TREE_CODE (fun) != FUNCTION_DECL) | |
1469 | { | |
f83e6885 | 1470 | if (!ctx->quiet && !*non_constant_p) |
5967b28b | 1471 | error_at (loc, "expression %qE does not designate a %<constexpr%> " |
09b42213 | 1472 | "function", fun); |
1473 | *non_constant_p = true; | |
1474 | return t; | |
1475 | } | |
1476 | if (DECL_CLONED_FUNCTION_P (fun)) | |
1477 | fun = DECL_CLONED_FUNCTION (fun); | |
6b71bdb4 | 1478 | |
1479 | if (is_ubsan_builtin_p (fun)) | |
1480 | return void_node; | |
1481 | ||
09b42213 | 1482 | if (is_builtin_fn (fun)) |
f1c6af10 | 1483 | return cxx_eval_builtin_function_call (ctx, t, fun, |
1227ba74 | 1484 | lval, non_constant_p, overflow_p); |
09b42213 | 1485 | if (!DECL_DECLARED_CONSTEXPR_P (fun)) |
1486 | { | |
f83e6885 | 1487 | if (!ctx->quiet) |
09b42213 | 1488 | { |
1dcd84cf | 1489 | if (!lambda_static_thunk_p (fun)) |
5967b28b | 1490 | error_at (loc, "call to non-%<constexpr%> function %qD", fun); |
09b42213 | 1491 | explain_invalid_constexpr_fn (fun); |
1492 | } | |
1493 | *non_constant_p = true; | |
1494 | return t; | |
1495 | } | |
1496 | ||
9ebe2ea3 | 1497 | constexpr_ctx new_ctx = *ctx; |
1498 | if (DECL_CONSTRUCTOR_P (fun) && !ctx->object | |
1499 | && TREE_CODE (t) == AGGR_INIT_EXPR) | |
1500 | { | |
1501 | /* We want to have an initialization target for an AGGR_INIT_EXPR. | |
1502 | If we don't already have one in CTX, use the AGGR_INIT_EXPR_SLOT. */ | |
1503 | new_ctx.object = AGGR_INIT_EXPR_SLOT (t); | |
1504 | tree ctor = new_ctx.ctor = build_constructor (DECL_CONTEXT (fun), NULL); | |
1505 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor) = true; | |
1506 | ctx->values->put (new_ctx.object, ctor); | |
1507 | ctx = &new_ctx; | |
1508 | } | |
1509 | ||
09b42213 | 1510 | /* Shortcut trivial constructor/op=. */ |
1511 | if (trivial_fn_p (fun)) | |
1512 | { | |
9ebe2ea3 | 1513 | tree init = NULL_TREE; |
09b42213 | 1514 | if (call_expr_nargs (t) == 2) |
9ebe2ea3 | 1515 | init = convert_from_reference (get_nth_callarg (t, 1)); |
09b42213 | 1516 | else if (TREE_CODE (t) == AGGR_INIT_EXPR |
1517 | && AGGR_INIT_ZERO_FIRST (t)) | |
9ebe2ea3 | 1518 | init = build_zero_init (DECL_CONTEXT (fun), NULL_TREE, false); |
1519 | if (init) | |
1520 | { | |
1521 | tree op = get_nth_callarg (t, 0); | |
1522 | if (is_dummy_object (op)) | |
1523 | op = ctx->object; | |
1524 | else | |
1525 | op = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (op)), op); | |
1526 | tree set = build2 (MODIFY_EXPR, TREE_TYPE (op), op, init); | |
0ce12360 | 1527 | new_ctx.call = &new_call; |
1528 | return cxx_eval_constant_expression (&new_ctx, set, lval, | |
9ebe2ea3 | 1529 | non_constant_p, overflow_p); |
1530 | } | |
09b42213 | 1531 | } |
1532 | ||
8afcf831 | 1533 | /* We can't defer instantiating the function any longer. */ |
1534 | if (!DECL_INITIAL (fun) | |
1535 | && DECL_TEMPLOID_INSTANTIATION (fun)) | |
1536 | { | |
31db86df | 1537 | location_t save_loc = input_location; |
1538 | input_location = loc; | |
8afcf831 | 1539 | ++function_depth; |
1540 | instantiate_decl (fun, /*defer_ok*/false, /*expl_inst*/false); | |
1541 | --function_depth; | |
31db86df | 1542 | input_location = save_loc; |
8afcf831 | 1543 | } |
1544 | ||
09b42213 | 1545 | /* If in direct recursive call, optimize definition search. */ |
0ce12360 | 1546 | if (ctx && ctx->call && ctx->call->fundef && ctx->call->fundef->decl == fun) |
cf72f34d | 1547 | new_call.fundef = ctx->call->fundef; |
09b42213 | 1548 | else |
1549 | { | |
1550 | new_call.fundef = retrieve_constexpr_fundef (fun); | |
d2a9b1c1 | 1551 | if (new_call.fundef == NULL || new_call.fundef->body == NULL |
1552 | || fun == current_function_decl) | |
09b42213 | 1553 | { |
f83e6885 | 1554 | if (!ctx->quiet) |
09b42213 | 1555 | { |
d2a9b1c1 | 1556 | /* We need to check for current_function_decl here in case we're |
1557 | being called during cp_fold_function, because at that point | |
1558 | DECL_INITIAL is set properly and we have a fundef but we | |
1559 | haven't lowered invisirefs yet (c++/70344). */ | |
1560 | if (DECL_INITIAL (fun) == error_mark_node | |
1561 | || fun == current_function_decl) | |
a0efa758 | 1562 | error_at (loc, "%qD called in a constant expression before its " |
1563 | "definition is complete", fun); | |
1564 | else if (DECL_INITIAL (fun)) | |
09b42213 | 1565 | { |
33603066 | 1566 | /* The definition of fun was somehow unsuitable. But pretend |
1567 | that lambda static thunks don't exist. */ | |
1568 | if (!lambda_static_thunk_p (fun)) | |
1569 | error_at (loc, "%qD called in a constant expression", fun); | |
09b42213 | 1570 | explain_invalid_constexpr_fn (fun); |
1571 | } | |
1572 | else | |
1573 | error_at (loc, "%qD used before its definition", fun); | |
1574 | } | |
1575 | *non_constant_p = true; | |
1576 | return t; | |
1577 | } | |
1578 | } | |
9c96033c | 1579 | |
c8f6aeb1 | 1580 | bool non_constant_args = false; |
cf72f34d | 1581 | cxx_bind_parameters_in_call (ctx, t, &new_call, |
c8f6aeb1 | 1582 | non_constant_p, overflow_p, &non_constant_args); |
09b42213 | 1583 | if (*non_constant_p) |
1584 | return t; | |
1585 | ||
1586 | depth_ok = push_cx_call_context (t); | |
1587 | ||
c8f6aeb1 | 1588 | tree result = NULL_TREE; |
09b42213 | 1589 | |
c8f6aeb1 | 1590 | constexpr_call *entry = NULL; |
37715b0f | 1591 | if (depth_ok && !non_constant_args) |
09b42213 | 1592 | { |
c8f6aeb1 | 1593 | new_call.hash = iterative_hash_template_arg |
1594 | (new_call.bindings, constexpr_fundef_hasher::hash (new_call.fundef)); | |
1595 | ||
1596 | /* If we have seen this call before, we are done. */ | |
1597 | maybe_initialize_constexpr_call_table (); | |
1598 | constexpr_call **slot | |
1599 | = constexpr_call_table->find_slot (&new_call, INSERT); | |
1600 | entry = *slot; | |
1601 | if (entry == NULL) | |
1602 | { | |
1603 | /* We need to keep a pointer to the entry, not just the slot, as the | |
1604 | slot can move in the call to cxx_eval_builtin_function_call. */ | |
1605 | *slot = entry = ggc_alloc<constexpr_call> (); | |
1606 | *entry = new_call; | |
1607 | } | |
2ba934c7 | 1608 | /* Calls that are in progress have their result set to NULL, |
c8f6aeb1 | 1609 | so that we can detect circular dependencies. */ |
1610 | else if (entry->result == NULL) | |
1611 | { | |
1612 | if (!ctx->quiet) | |
1613 | error ("call has circular dependency"); | |
1614 | *non_constant_p = true; | |
1615 | entry->result = result = error_mark_node; | |
1616 | } | |
1617 | else | |
1618 | result = entry->result; | |
09b42213 | 1619 | } |
1620 | ||
1621 | if (!depth_ok) | |
1622 | { | |
f83e6885 | 1623 | if (!ctx->quiet) |
5967b28b | 1624 | error ("%<constexpr%> evaluation depth exceeds maximum of %d (use " |
09b42213 | 1625 | "-fconstexpr-depth= to increase the maximum)", |
1626 | max_constexpr_depth); | |
1627 | *non_constant_p = true; | |
c8f6aeb1 | 1628 | result = error_mark_node; |
09b42213 | 1629 | } |
1630 | else | |
1631 | { | |
ab099088 | 1632 | if (result && result != error_mark_node) |
1633 | /* OK */; | |
1634 | else if (!DECL_SAVED_TREE (fun)) | |
1635 | { | |
1636 | /* When at_eof >= 2, cgraph has started throwing away | |
1637 | DECL_SAVED_TREE, so fail quietly. FIXME we get here because of | |
1638 | late code generation for VEC_INIT_EXPR, which needs to be | |
1639 | completely reconsidered. */ | |
1640 | gcc_assert (at_eof >= 2 && ctx->quiet); | |
1641 | *non_constant_p = true; | |
1642 | } | |
1643 | else | |
cf72f34d | 1644 | { |
4f7ebe46 | 1645 | tree body, parms, res; |
88a59139 | 1646 | |
4f7ebe46 | 1647 | /* Reuse or create a new unshared copy of this function's body. */ |
a050099a | 1648 | tree copy = get_fundef_copy (fun); |
1649 | body = TREE_PURPOSE (copy); | |
1650 | parms = TREE_VALUE (copy); | |
1651 | res = TREE_TYPE (copy); | |
88a59139 | 1652 | |
1653 | /* Associate the bindings with the remapped parms. */ | |
1654 | tree bound = new_call.bindings; | |
1655 | tree remapped = parms; | |
1656 | while (bound) | |
9c96033c | 1657 | { |
88a59139 | 1658 | tree oparm = TREE_PURPOSE (bound); |
1659 | tree arg = TREE_VALUE (bound); | |
1660 | gcc_assert (DECL_NAME (remapped) == DECL_NAME (oparm)); | |
5898f0d7 | 1661 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 1662 | arg = unshare_constructor (arg); |
88a59139 | 1663 | ctx->values->put (remapped, arg); |
1664 | bound = TREE_CHAIN (bound); | |
1665 | remapped = DECL_CHAIN (remapped); | |
9c96033c | 1666 | } |
88a59139 | 1667 | /* Add the RESULT_DECL to the values map, too. */ |
1668 | tree slot = NULL_TREE; | |
1669 | if (DECL_BY_REFERENCE (res)) | |
9c96033c | 1670 | { |
88a59139 | 1671 | slot = AGGR_INIT_EXPR_SLOT (t); |
1672 | tree addr = build_address (slot); | |
1673 | addr = build_nop (TREE_TYPE (res), addr); | |
1674 | ctx->values->put (res, addr); | |
1675 | ctx->values->put (slot, NULL_TREE); | |
1676 | } | |
1677 | else | |
1678 | ctx->values->put (res, NULL_TREE); | |
9c96033c | 1679 | |
4f7ebe46 | 1680 | /* Track the callee's evaluated SAVE_EXPRs so that we can forget |
1681 | their values after the call. */ | |
1682 | constexpr_ctx ctx_with_save_exprs = *ctx; | |
1683 | hash_set<tree> save_exprs; | |
1684 | ctx_with_save_exprs.save_exprs = &save_exprs; | |
43b7271d | 1685 | ctx_with_save_exprs.call = &new_call; |
4f7ebe46 | 1686 | |
88a59139 | 1687 | tree jump_target = NULL_TREE; |
4f7ebe46 | 1688 | cxx_eval_constant_expression (&ctx_with_save_exprs, body, |
88a59139 | 1689 | lval, non_constant_p, overflow_p, |
1690 | &jump_target); | |
9c96033c | 1691 | |
88a59139 | 1692 | if (DECL_CONSTRUCTOR_P (fun)) |
1693 | /* This can be null for a subobject constructor call, in | |
1694 | which case what we care about is the initialization | |
1695 | side-effects rather than the value. We could get at the | |
1696 | value by evaluating *this, but we don't bother; there's | |
1697 | no need to put such a call in the hash table. */ | |
1698 | result = lval ? ctx->object : ctx->ctor; | |
1699 | else if (VOID_TYPE_P (TREE_TYPE (res))) | |
1700 | result = void_node; | |
1701 | else | |
1702 | { | |
1703 | result = *ctx->values->get (slot ? slot : res); | |
1704 | if (result == NULL_TREE && !*non_constant_p) | |
9c96033c | 1705 | { |
88a59139 | 1706 | if (!ctx->quiet) |
5967b28b | 1707 | error ("%<constexpr%> call flows off the end " |
88a59139 | 1708 | "of the function"); |
1709 | *non_constant_p = true; | |
9c96033c | 1710 | } |
9c96033c | 1711 | } |
88a59139 | 1712 | |
4f7ebe46 | 1713 | /* Forget the saved values of the callee's SAVE_EXPRs. */ |
1714 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
1715 | iter != save_exprs.end(); ++iter) | |
1716 | ctx_with_save_exprs.values->remove (*iter); | |
1717 | ||
88a59139 | 1718 | /* Remove the parms/result from the values map. Is it worth |
1719 | bothering to do this when the map itself is only live for | |
1720 | one constexpr evaluation? If so, maybe also clear out | |
1721 | other vars from call, maybe in BIND_EXPR handling? */ | |
1722 | ctx->values->remove (res); | |
1723 | if (slot) | |
1724 | ctx->values->remove (slot); | |
1725 | for (tree parm = parms; parm; parm = TREE_CHAIN (parm)) | |
1726 | ctx->values->remove (parm); | |
4f7ebe46 | 1727 | |
1728 | /* Make the unshared function copy we used available for re-use. */ | |
1729 | save_fundef_copy (fun, copy); | |
cf72f34d | 1730 | } |
9c96033c | 1731 | |
09b42213 | 1732 | if (result == error_mark_node) |
1733 | *non_constant_p = true; | |
c3f376bf | 1734 | if (*non_constant_p || *overflow_p) |
c8f6aeb1 | 1735 | result = error_mark_node; |
88a59139 | 1736 | else if (!result) |
9c96033c | 1737 | result = void_node; |
c8f6aeb1 | 1738 | if (entry) |
1739 | entry->result = result; | |
09b42213 | 1740 | } |
1741 | ||
c6d97004 | 1742 | /* The result of a constexpr function must be completely initialized. */ |
1743 | if (TREE_CODE (result) == CONSTRUCTOR) | |
79cdb4f5 | 1744 | clear_no_implicit_zero (result); |
c6d97004 | 1745 | |
09b42213 | 1746 | pop_cx_call_context (); |
e283bb4f | 1747 | return unshare_constructor (result); |
09b42213 | 1748 | } |
1749 | ||
1750 | /* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */ | |
1751 | ||
1752 | bool | |
1753 | reduced_constant_expression_p (tree t) | |
1754 | { | |
1755 | switch (TREE_CODE (t)) | |
1756 | { | |
1757 | case PTRMEM_CST: | |
1758 | /* Even if we can't lower this yet, it's constant. */ | |
1759 | return true; | |
1760 | ||
1761 | case CONSTRUCTOR: | |
1762 | /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */ | |
56da7fe6 | 1763 | tree idx, val, field; unsigned HOST_WIDE_INT i; |
1764 | if (CONSTRUCTOR_NO_IMPLICIT_ZERO (t)) | |
1765 | field = next_initializable_field (TYPE_FIELDS (TREE_TYPE (t))); | |
1766 | else | |
1767 | field = NULL_TREE; | |
1768 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t), i, idx, val) | |
ce4ffd9e | 1769 | { |
56da7fe6 | 1770 | if (!val) |
ce4ffd9e | 1771 | /* We're in the middle of initializing this element. */ |
1772 | return false; | |
56da7fe6 | 1773 | if (!reduced_constant_expression_p (val)) |
ce4ffd9e | 1774 | return false; |
56da7fe6 | 1775 | if (field) |
1776 | { | |
1777 | if (idx != field) | |
1778 | return false; | |
1779 | field = next_initializable_field (DECL_CHAIN (field)); | |
1780 | } | |
ce4ffd9e | 1781 | } |
56da7fe6 | 1782 | if (field) |
1783 | return false; | |
1784 | else if (CONSTRUCTOR_NO_IMPLICIT_ZERO (t)) | |
1785 | /* All the fields are initialized. */ | |
1786 | CONSTRUCTOR_NO_IMPLICIT_ZERO (t) = false; | |
09b42213 | 1787 | return true; |
1788 | ||
1789 | default: | |
1790 | /* FIXME are we calling this too much? */ | |
1791 | return initializer_constant_valid_p (t, TREE_TYPE (t)) != NULL_TREE; | |
1792 | } | |
1793 | } | |
1794 | ||
1795 | /* Some expressions may have constant operands but are not constant | |
1796 | themselves, such as 1/0. Call this function (or rather, the macro | |
1797 | following it) to check for that condition. | |
1798 | ||
1799 | We only call this in places that require an arithmetic constant, not in | |
1800 | places where we might have a non-constant expression that can be a | |
1801 | component of a constant expression, such as the address of a constexpr | |
1802 | variable that might be dereferenced later. */ | |
1803 | ||
1804 | static bool | |
1805 | verify_constant (tree t, bool allow_non_constant, bool *non_constant_p, | |
1806 | bool *overflow_p) | |
1807 | { | |
1808 | if (!*non_constant_p && !reduced_constant_expression_p (t)) | |
1809 | { | |
1810 | if (!allow_non_constant) | |
1811 | error ("%q+E is not a constant expression", t); | |
1812 | *non_constant_p = true; | |
1813 | } | |
1814 | if (TREE_OVERFLOW_P (t)) | |
1815 | { | |
1816 | if (!allow_non_constant) | |
1817 | { | |
1818 | permerror (input_location, "overflow in constant expression"); | |
1819 | /* If we're being permissive (and are in an enforcing | |
1820 | context), ignore the overflow. */ | |
1821 | if (flag_permissive) | |
1822 | return *non_constant_p; | |
1823 | } | |
1824 | *overflow_p = true; | |
1825 | } | |
1826 | return *non_constant_p; | |
1827 | } | |
1828 | ||
2b035ffe | 1829 | /* Check whether the shift operation with code CODE and type TYPE on LHS |
1830 | and RHS is undefined. If it is, give an error with an explanation, | |
1831 | and return true; return false otherwise. */ | |
1832 | ||
1833 | static bool | |
1834 | cxx_eval_check_shift_p (location_t loc, const constexpr_ctx *ctx, | |
1835 | enum tree_code code, tree type, tree lhs, tree rhs) | |
1836 | { | |
1837 | if ((code != LSHIFT_EXPR && code != RSHIFT_EXPR) | |
1838 | || TREE_CODE (lhs) != INTEGER_CST | |
1839 | || TREE_CODE (rhs) != INTEGER_CST) | |
1840 | return false; | |
1841 | ||
1842 | tree lhstype = TREE_TYPE (lhs); | |
1843 | unsigned HOST_WIDE_INT uprec = TYPE_PRECISION (TREE_TYPE (lhs)); | |
1844 | ||
1845 | /* [expr.shift] The behavior is undefined if the right operand | |
1846 | is negative, or greater than or equal to the length in bits | |
1847 | of the promoted left operand. */ | |
1848 | if (tree_int_cst_sgn (rhs) == -1) | |
1849 | { | |
1850 | if (!ctx->quiet) | |
91d87e22 | 1851 | permerror (loc, "right operand of shift expression %q+E is negative", |
1852 | build2_loc (loc, code, type, lhs, rhs)); | |
1853 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1854 | } |
1855 | if (compare_tree_int (rhs, uprec) >= 0) | |
1856 | { | |
1857 | if (!ctx->quiet) | |
91d87e22 | 1858 | permerror (loc, "right operand of shift expression %q+E is >= than " |
1859 | "the precision of the left operand", | |
1860 | build2_loc (loc, code, type, lhs, rhs)); | |
1861 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1862 | } |
1863 | ||
1864 | /* The value of E1 << E2 is E1 left-shifted E2 bit positions; [...] | |
1865 | if E1 has a signed type and non-negative value, and E1x2^E2 is | |
1866 | representable in the corresponding unsigned type of the result type, | |
1867 | then that value, converted to the result type, is the resulting value; | |
1868 | otherwise, the behavior is undefined. */ | |
1869 | if (code == LSHIFT_EXPR && !TYPE_UNSIGNED (lhstype) | |
1870 | && (cxx_dialect >= cxx11)) | |
1871 | { | |
1872 | if (tree_int_cst_sgn (lhs) == -1) | |
1873 | { | |
1874 | if (!ctx->quiet) | |
91d87e22 | 1875 | permerror (loc, |
1876 | "left operand of shift expression %q+E is negative", | |
1877 | build2_loc (loc, code, type, lhs, rhs)); | |
1878 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1879 | } |
1880 | /* For signed x << y the following: | |
1881 | (unsigned) x >> ((prec (lhs) - 1) - y) | |
1882 | if > 1, is undefined. The right-hand side of this formula | |
1883 | is the highest bit of the LHS that can be set (starting from 0), | |
1884 | so that the shift doesn't overflow. We then right-shift the LHS | |
1885 | to see whether any other bit is set making the original shift | |
1886 | undefined -- the result is not representable in the corresponding | |
1887 | unsigned type. */ | |
1888 | tree t = build_int_cst (unsigned_type_node, uprec - 1); | |
1889 | t = fold_build2 (MINUS_EXPR, unsigned_type_node, t, rhs); | |
1890 | tree ulhs = fold_convert (unsigned_type_for (lhstype), lhs); | |
1891 | t = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ulhs), ulhs, t); | |
1892 | if (tree_int_cst_lt (integer_one_node, t)) | |
1893 | { | |
1894 | if (!ctx->quiet) | |
91d87e22 | 1895 | permerror (loc, "shift expression %q+E overflows", |
1896 | build2_loc (loc, code, type, lhs, rhs)); | |
1897 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1898 | } |
1899 | } | |
1900 | return false; | |
1901 | } | |
1902 | ||
09b42213 | 1903 | /* Subroutine of cxx_eval_constant_expression. |
1904 | Attempt to reduce the unary expression tree T to a compile time value. | |
1905 | If successful, return the value. Otherwise issue a diagnostic | |
1906 | and return error_mark_node. */ | |
1907 | ||
1908 | static tree | |
cf72f34d | 1909 | cxx_eval_unary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 1910 | bool /*lval*/, |
09b42213 | 1911 | bool *non_constant_p, bool *overflow_p) |
1912 | { | |
1913 | tree r; | |
1914 | tree orig_arg = TREE_OPERAND (t, 0); | |
c8f6aeb1 | 1915 | tree arg = cxx_eval_constant_expression (ctx, orig_arg, /*lval*/false, |
1916 | non_constant_p, overflow_p); | |
09b42213 | 1917 | VERIFY_CONSTANT (arg); |
93add516 | 1918 | location_t loc = EXPR_LOCATION (t); |
1919 | enum tree_code code = TREE_CODE (t); | |
1920 | tree type = TREE_TYPE (t); | |
1921 | r = fold_unary_loc (loc, code, type, arg); | |
1922 | if (r == NULL_TREE) | |
1923 | { | |
1924 | if (arg == orig_arg) | |
1925 | r = t; | |
1926 | else | |
1927 | r = build1_loc (loc, code, type, arg); | |
1928 | } | |
09b42213 | 1929 | VERIFY_CONSTANT (r); |
1930 | return r; | |
1931 | } | |
1932 | ||
46fad8d5 | 1933 | /* Helper function for cxx_eval_binary_expression. Try to optimize |
1934 | original POINTER_PLUS_EXPR T, LHS p+ RHS, return NULL_TREE if the | |
1935 | generic folding should be used. */ | |
1936 | ||
1937 | static tree | |
1938 | cxx_fold_pointer_plus_expression (const constexpr_ctx *ctx, tree t, | |
1939 | tree lhs, tree rhs, bool *non_constant_p, | |
1940 | bool *overflow_p) | |
1941 | { | |
1942 | STRIP_NOPS (lhs); | |
1943 | if (TREE_CODE (lhs) != ADDR_EXPR) | |
1944 | return NULL_TREE; | |
1945 | ||
1946 | lhs = TREE_OPERAND (lhs, 0); | |
1947 | ||
1948 | /* &A[i] p+ j => &A[i + j] */ | |
1949 | if (TREE_CODE (lhs) == ARRAY_REF | |
1950 | && TREE_CODE (TREE_OPERAND (lhs, 1)) == INTEGER_CST | |
1951 | && TREE_CODE (rhs) == INTEGER_CST | |
1952 | && TYPE_SIZE_UNIT (TREE_TYPE (lhs)) | |
1953 | && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (lhs))) == INTEGER_CST) | |
1954 | { | |
1955 | tree orig_type = TREE_TYPE (t); | |
1956 | location_t loc = EXPR_LOCATION (t); | |
1957 | tree type = TREE_TYPE (lhs); | |
1958 | ||
1959 | t = fold_convert_loc (loc, ssizetype, TREE_OPERAND (lhs, 1)); | |
1960 | tree nelts = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (lhs, 0))); | |
1961 | nelts = cxx_eval_constant_expression (ctx, nelts, false, non_constant_p, | |
1962 | overflow_p); | |
1963 | if (*non_constant_p) | |
1964 | return NULL_TREE; | |
1965 | /* Don't fold an out-of-bound access. */ | |
1966 | if (!tree_int_cst_le (t, nelts)) | |
1967 | return NULL_TREE; | |
1968 | rhs = cp_fold_convert (ssizetype, rhs); | |
1969 | /* Don't fold if rhs can't be divided exactly by TYPE_SIZE_UNIT. | |
1970 | constexpr int A[1]; ... (char *)&A[0] + 1 */ | |
1971 | if (!integer_zerop (fold_build2_loc (loc, TRUNC_MOD_EXPR, sizetype, | |
1972 | rhs, TYPE_SIZE_UNIT (type)))) | |
1973 | return NULL_TREE; | |
1974 | /* Make sure to treat the second operand of POINTER_PLUS_EXPR | |
1975 | as signed. */ | |
1976 | rhs = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, rhs, | |
1977 | TYPE_SIZE_UNIT (type)); | |
1978 | t = size_binop_loc (loc, PLUS_EXPR, rhs, t); | |
1979 | t = build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (lhs, 0), | |
1980 | t, NULL_TREE, NULL_TREE); | |
1981 | t = cp_build_addr_expr (t, tf_warning_or_error); | |
1982 | t = cp_fold_convert (orig_type, t); | |
1983 | return cxx_eval_constant_expression (ctx, t, /*lval*/false, | |
1984 | non_constant_p, overflow_p); | |
1985 | } | |
1986 | ||
1987 | return NULL_TREE; | |
1988 | } | |
1989 | ||
09b42213 | 1990 | /* Subroutine of cxx_eval_constant_expression. |
1991 | Like cxx_eval_unary_expression, except for binary expressions. */ | |
1992 | ||
1993 | static tree | |
cf72f34d | 1994 | cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 1995 | bool /*lval*/, |
09b42213 | 1996 | bool *non_constant_p, bool *overflow_p) |
1997 | { | |
f7ef5392 | 1998 | tree r = NULL_TREE; |
09b42213 | 1999 | tree orig_lhs = TREE_OPERAND (t, 0); |
2000 | tree orig_rhs = TREE_OPERAND (t, 1); | |
2001 | tree lhs, rhs; | |
c8f6aeb1 | 2002 | lhs = cxx_eval_constant_expression (ctx, orig_lhs, /*lval*/false, |
b2a43197 | 2003 | non_constant_p, overflow_p); |
6d6737d9 | 2004 | /* Don't VERIFY_CONSTANT here, it's unnecessary and will break pointer |
2005 | subtraction. */ | |
2006 | if (*non_constant_p) | |
2007 | return t; | |
c8f6aeb1 | 2008 | rhs = cxx_eval_constant_expression (ctx, orig_rhs, /*lval*/false, |
b2a43197 | 2009 | non_constant_p, overflow_p); |
6d6737d9 | 2010 | if (*non_constant_p) |
2011 | return t; | |
93add516 | 2012 | |
2013 | location_t loc = EXPR_LOCATION (t); | |
2014 | enum tree_code code = TREE_CODE (t); | |
2015 | tree type = TREE_TYPE (t); | |
f7ef5392 | 2016 | |
2017 | if (code == EQ_EXPR || code == NE_EXPR) | |
2018 | { | |
2019 | bool is_code_eq = (code == EQ_EXPR); | |
2020 | ||
2021 | if (TREE_CODE (lhs) == PTRMEM_CST | |
2022 | && TREE_CODE (rhs) == PTRMEM_CST) | |
2023 | r = constant_boolean_node (cp_tree_equal (lhs, rhs) == is_code_eq, | |
2024 | type); | |
2025 | else if ((TREE_CODE (lhs) == PTRMEM_CST | |
2026 | || TREE_CODE (rhs) == PTRMEM_CST) | |
2027 | && (null_member_pointer_value_p (lhs) | |
2028 | || null_member_pointer_value_p (rhs))) | |
2029 | r = constant_boolean_node (!is_code_eq, type); | |
f31f4e9c | 2030 | else if (TREE_CODE (lhs) == PTRMEM_CST) |
2031 | lhs = cplus_expand_constant (lhs); | |
2032 | else if (TREE_CODE (rhs) == PTRMEM_CST) | |
2033 | rhs = cplus_expand_constant (rhs); | |
f7ef5392 | 2034 | } |
cb768824 | 2035 | if (code == POINTER_PLUS_EXPR && !*non_constant_p |
2036 | && integer_zerop (lhs) && !integer_zerop (rhs)) | |
2037 | { | |
2038 | if (!ctx->quiet) | |
2039 | error ("arithmetic involving a null pointer in %qE", lhs); | |
2040 | return t; | |
2041 | } | |
46fad8d5 | 2042 | else if (code == POINTER_PLUS_EXPR) |
2043 | r = cxx_fold_pointer_plus_expression (ctx, t, lhs, rhs, non_constant_p, | |
2044 | overflow_p); | |
f7ef5392 | 2045 | |
2046 | if (r == NULL_TREE) | |
2047 | r = fold_binary_loc (loc, code, type, lhs, rhs); | |
2048 | ||
93add516 | 2049 | if (r == NULL_TREE) |
2050 | { | |
2051 | if (lhs == orig_lhs && rhs == orig_rhs) | |
2052 | r = t; | |
2053 | else | |
2054 | r = build2_loc (loc, code, type, lhs, rhs); | |
2055 | } | |
2b035ffe | 2056 | else if (cxx_eval_check_shift_p (loc, ctx, code, type, lhs, rhs)) |
2057 | *non_constant_p = true; | |
6d6737d9 | 2058 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
2059 | a local array in a constexpr function. */ | |
2060 | bool ptr = POINTER_TYPE_P (TREE_TYPE (lhs)); | |
35f2c28f | 2061 | if (!ptr) |
aae7465c | 2062 | VERIFY_CONSTANT (r); |
09b42213 | 2063 | return r; |
2064 | } | |
2065 | ||
2066 | /* Subroutine of cxx_eval_constant_expression. | |
2067 | Attempt to evaluate condition expressions. Dead branches are not | |
2068 | looked into. */ | |
2069 | ||
2070 | static tree | |
cf72f34d | 2071 | cxx_eval_conditional_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2072 | bool lval, |
00f21715 | 2073 | bool *non_constant_p, bool *overflow_p, |
2074 | tree *jump_target) | |
09b42213 | 2075 | { |
cf72f34d | 2076 | tree val = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
c8f6aeb1 | 2077 | /*lval*/false, |
b2a43197 | 2078 | non_constant_p, overflow_p); |
09b42213 | 2079 | VERIFY_CONSTANT (val); |
2080 | /* Don't VERIFY_CONSTANT the other operands. */ | |
2081 | if (integer_zerop (val)) | |
cf72f34d | 2082 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), |
1227ba74 | 2083 | lval, |
00f21715 | 2084 | non_constant_p, overflow_p, |
2085 | jump_target); | |
cf72f34d | 2086 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2087 | lval, |
00f21715 | 2088 | non_constant_p, overflow_p, |
2089 | jump_target); | |
09b42213 | 2090 | } |
2091 | ||
31595caf | 2092 | /* Subroutine of cxx_eval_constant_expression. |
2093 | Attempt to evaluate vector condition expressions. Unlike | |
2094 | cxx_eval_conditional_expression, VEC_COND_EXPR acts like a normal | |
2095 | ternary arithmetics operation, where all 3 arguments have to be | |
2096 | evaluated as constants and then folding computes the result from | |
2097 | them. */ | |
2098 | ||
2099 | static tree | |
2100 | cxx_eval_vector_conditional_expression (const constexpr_ctx *ctx, tree t, | |
2101 | bool *non_constant_p, bool *overflow_p) | |
2102 | { | |
2103 | tree arg1 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
2104 | /*lval*/false, | |
2105 | non_constant_p, overflow_p); | |
2106 | VERIFY_CONSTANT (arg1); | |
2107 | tree arg2 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
2108 | /*lval*/false, | |
2109 | non_constant_p, overflow_p); | |
2110 | VERIFY_CONSTANT (arg2); | |
2111 | tree arg3 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
2112 | /*lval*/false, | |
2113 | non_constant_p, overflow_p); | |
2114 | VERIFY_CONSTANT (arg3); | |
2115 | location_t loc = EXPR_LOCATION (t); | |
2116 | tree type = TREE_TYPE (t); | |
2117 | tree r = fold_ternary_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2118 | if (r == NULL_TREE) | |
2119 | { | |
2120 | if (arg1 == TREE_OPERAND (t, 0) | |
2121 | && arg2 == TREE_OPERAND (t, 1) | |
2122 | && arg3 == TREE_OPERAND (t, 2)) | |
2123 | r = t; | |
2124 | else | |
2125 | r = build3_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2126 | } | |
2127 | VERIFY_CONSTANT (r); | |
2128 | return r; | |
2129 | } | |
2130 | ||
7963b19d | 2131 | /* Returns less than, equal to, or greater than zero if KEY is found to be |
2132 | less than, to match, or to be greater than the constructor_elt's INDEX. */ | |
2133 | ||
2134 | static int | |
2135 | array_index_cmp (tree key, tree index) | |
2136 | { | |
2137 | gcc_assert (TREE_CODE (key) == INTEGER_CST); | |
2138 | ||
2139 | switch (TREE_CODE (index)) | |
2140 | { | |
2141 | case INTEGER_CST: | |
2142 | return tree_int_cst_compare (key, index); | |
2143 | case RANGE_EXPR: | |
2144 | { | |
2145 | tree lo = TREE_OPERAND (index, 0); | |
2146 | tree hi = TREE_OPERAND (index, 1); | |
2147 | if (tree_int_cst_lt (key, lo)) | |
2148 | return -1; | |
2149 | else if (tree_int_cst_lt (hi, key)) | |
2150 | return 1; | |
2151 | else | |
2152 | return 0; | |
2153 | } | |
2154 | default: | |
2155 | gcc_unreachable (); | |
2156 | } | |
2157 | } | |
2158 | ||
2159 | /* Returns the index of the constructor_elt of ARY which matches DINDEX, or -1 | |
2160 | if none. If INSERT is true, insert a matching element rather than fail. */ | |
2161 | ||
2162 | static HOST_WIDE_INT | |
2163 | find_array_ctor_elt (tree ary, tree dindex, bool insert = false) | |
2164 | { | |
2165 | if (tree_int_cst_sgn (dindex) < 0) | |
2166 | return -1; | |
2167 | ||
2168 | unsigned HOST_WIDE_INT i = tree_to_uhwi (dindex); | |
2169 | vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (ary); | |
2170 | unsigned HOST_WIDE_INT len = vec_safe_length (elts); | |
2171 | ||
2172 | unsigned HOST_WIDE_INT end = len; | |
2173 | unsigned HOST_WIDE_INT begin = 0; | |
2174 | ||
2175 | /* If the last element of the CONSTRUCTOR has its own index, we can assume | |
2176 | that the same is true of the other elements and index directly. */ | |
2177 | if (end > 0) | |
2178 | { | |
2179 | tree cindex = (*elts)[end-1].index; | |
2180 | if (TREE_CODE (cindex) == INTEGER_CST | |
2181 | && compare_tree_int (cindex, end-1) == 0) | |
2182 | { | |
2183 | if (i < end) | |
2184 | return i; | |
2185 | else | |
2186 | begin = end; | |
2187 | } | |
2188 | } | |
2189 | ||
2190 | /* Otherwise, find a matching index by means of a binary search. */ | |
2191 | while (begin != end) | |
2192 | { | |
2193 | unsigned HOST_WIDE_INT middle = (begin + end) / 2; | |
f0b916c7 | 2194 | constructor_elt &elt = (*elts)[middle]; |
2195 | tree idx = elt.index; | |
7963b19d | 2196 | |
f0b916c7 | 2197 | int cmp = array_index_cmp (dindex, idx); |
7963b19d | 2198 | if (cmp < 0) |
2199 | end = middle; | |
2200 | else if (cmp > 0) | |
2201 | begin = middle + 1; | |
2202 | else | |
f0b916c7 | 2203 | { |
2204 | if (insert && TREE_CODE (idx) == RANGE_EXPR) | |
2205 | { | |
2206 | /* We need to split the range. */ | |
2207 | constructor_elt e; | |
2208 | tree lo = TREE_OPERAND (idx, 0); | |
2209 | tree hi = TREE_OPERAND (idx, 1); | |
2210 | if (tree_int_cst_lt (lo, dindex)) | |
2211 | { | |
2212 | /* There are still some lower elts; shorten the range. */ | |
2213 | tree new_hi = int_const_binop (MINUS_EXPR, dindex, | |
2214 | size_one_node); | |
2215 | if (tree_int_cst_equal (lo, new_hi)) | |
2216 | /* Only one element left, no longer a range. */ | |
2217 | elt.index = lo; | |
2218 | else | |
2219 | TREE_OPERAND (idx, 1) = new_hi; | |
2220 | /* Append the element we want to insert. */ | |
2221 | ++middle; | |
2222 | e.index = dindex; | |
e283bb4f | 2223 | e.value = unshare_constructor (elt.value); |
f0b916c7 | 2224 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle, e); |
2225 | } | |
2226 | else | |
2227 | /* No lower elts, the range elt is now ours. */ | |
2228 | elt.index = dindex; | |
2229 | ||
2230 | if (tree_int_cst_lt (dindex, hi)) | |
2231 | { | |
2232 | /* There are still some higher elts; append a range. */ | |
2233 | tree new_lo = int_const_binop (PLUS_EXPR, dindex, | |
2234 | size_one_node); | |
2235 | if (tree_int_cst_equal (new_lo, hi)) | |
2236 | e.index = hi; | |
2237 | else | |
2238 | e.index = build2 (RANGE_EXPR, sizetype, new_lo, hi); | |
e283bb4f | 2239 | e.value = unshare_constructor (elt.value); |
f0b916c7 | 2240 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle+1, e); |
2241 | } | |
2242 | } | |
2243 | return middle; | |
2244 | } | |
7963b19d | 2245 | } |
2246 | ||
2247 | if (insert) | |
2248 | { | |
2249 | constructor_elt e = { dindex, NULL_TREE }; | |
2250 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), end, e); | |
2251 | return end; | |
2252 | } | |
2253 | ||
2254 | return -1; | |
2255 | } | |
2256 | ||
40df9099 | 2257 | /* Under the control of CTX, issue a detailed diagnostic for |
2258 | an out-of-bounds subscript INDEX into the expression ARRAY. */ | |
2259 | ||
2260 | static void | |
2261 | diag_array_subscript (const constexpr_ctx *ctx, tree array, tree index) | |
2262 | { | |
2263 | if (!ctx->quiet) | |
2264 | { | |
2265 | tree arraytype = TREE_TYPE (array); | |
2266 | ||
2267 | /* Convert the unsigned array subscript to a signed integer to avoid | |
2268 | printing huge numbers for small negative values. */ | |
2269 | tree sidx = fold_convert (ssizetype, index); | |
2270 | if (DECL_P (array)) | |
2271 | { | |
2272 | error ("array subscript value %qE is outside the bounds " | |
2273 | "of array %qD of type %qT", sidx, array, arraytype); | |
2274 | inform (DECL_SOURCE_LOCATION (array), "declared here"); | |
2275 | } | |
2276 | else | |
2277 | error ("array subscript value %qE is outside the bounds " | |
2278 | "of array type %qT", sidx, arraytype); | |
2279 | } | |
2280 | } | |
7963b19d | 2281 | |
92fe8840 | 2282 | /* Extract element INDEX consisting of CHARS_PER_ELT chars from |
2283 | STRING_CST STRING. */ | |
2284 | ||
2285 | static tree | |
2286 | extract_string_elt (tree string, unsigned chars_per_elt, unsigned index) | |
2287 | { | |
2288 | tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (string))); | |
2289 | tree r; | |
2290 | ||
2291 | if (chars_per_elt == 1) | |
2292 | r = build_int_cst (type, TREE_STRING_POINTER (string)[index]); | |
2293 | else | |
2294 | { | |
2295 | const unsigned char *ptr | |
2296 | = ((const unsigned char *)TREE_STRING_POINTER (string) | |
2297 | + index * chars_per_elt); | |
2298 | r = native_interpret_expr (type, ptr, chars_per_elt); | |
2299 | } | |
2300 | return r; | |
2301 | } | |
2302 | ||
09b42213 | 2303 | /* Subroutine of cxx_eval_constant_expression. |
2304 | Attempt to reduce a reference to an array slot. */ | |
2305 | ||
2306 | static tree | |
cf72f34d | 2307 | cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2308 | bool lval, |
09b42213 | 2309 | bool *non_constant_p, bool *overflow_p) |
2310 | { | |
2311 | tree oldary = TREE_OPERAND (t, 0); | |
cf72f34d | 2312 | tree ary = cxx_eval_constant_expression (ctx, oldary, |
1227ba74 | 2313 | lval, |
b2a43197 | 2314 | non_constant_p, overflow_p); |
09b42213 | 2315 | tree index, oldidx; |
cf3cefc9 | 2316 | HOST_WIDE_INT i = 0; |
2317 | tree elem_type = NULL_TREE; | |
2318 | unsigned len = 0, elem_nchars = 1; | |
09b42213 | 2319 | if (*non_constant_p) |
2320 | return t; | |
2321 | oldidx = TREE_OPERAND (t, 1); | |
cf72f34d | 2322 | index = cxx_eval_constant_expression (ctx, oldidx, |
f83e6885 | 2323 | false, |
b2a43197 | 2324 | non_constant_p, overflow_p); |
09b42213 | 2325 | VERIFY_CONSTANT (index); |
cf3cefc9 | 2326 | if (!lval) |
09b42213 | 2327 | { |
cf3cefc9 | 2328 | elem_type = TREE_TYPE (TREE_TYPE (ary)); |
2329 | if (TREE_CODE (ary) == VIEW_CONVERT_EXPR | |
2330 | && VECTOR_TYPE_P (TREE_TYPE (TREE_OPERAND (ary, 0))) | |
2331 | && TREE_TYPE (t) == TREE_TYPE (TREE_TYPE (TREE_OPERAND (ary, 0)))) | |
2332 | ary = TREE_OPERAND (ary, 0); | |
2333 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2334 | len = CONSTRUCTOR_NELTS (ary); | |
2335 | else if (TREE_CODE (ary) == STRING_CST) | |
2336 | { | |
2337 | elem_nchars = (TYPE_PRECISION (elem_type) | |
2338 | / TYPE_PRECISION (char_type_node)); | |
2339 | len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars; | |
2340 | } | |
2341 | else if (TREE_CODE (ary) == VECTOR_CST) | |
2342 | len = VECTOR_CST_NELTS (ary); | |
2343 | else | |
2344 | { | |
2345 | /* We can't do anything with other tree codes, so use | |
2346 | VERIFY_CONSTANT to complain and fail. */ | |
2347 | VERIFY_CONSTANT (ary); | |
2348 | gcc_unreachable (); | |
2349 | } | |
aed8dc7f | 2350 | |
cf3cefc9 | 2351 | if (!tree_fits_shwi_p (index) |
2352 | || (i = tree_to_shwi (index)) < 0) | |
2353 | { | |
2354 | diag_array_subscript (ctx, ary, index); | |
2355 | *non_constant_p = true; | |
2356 | return t; | |
2357 | } | |
7963b19d | 2358 | } |
2359 | ||
7345b977 | 2360 | tree nelts; |
2361 | if (TREE_CODE (TREE_TYPE (ary)) == ARRAY_TYPE) | |
2362 | nelts = array_type_nelts_top (TREE_TYPE (ary)); | |
2363 | else if (VECTOR_TYPE_P (TREE_TYPE (ary))) | |
2364 | nelts = size_int (TYPE_VECTOR_SUBPARTS (TREE_TYPE (ary))); | |
2365 | else | |
2366 | gcc_unreachable (); | |
2367 | ||
ce6a6978 | 2368 | /* For VLAs, the number of elements won't be an integer constant. */ |
2369 | nelts = cxx_eval_constant_expression (ctx, nelts, false, non_constant_p, | |
2370 | overflow_p); | |
2371 | VERIFY_CONSTANT (nelts); | |
0acc6340 | 2372 | if ((lval |
2373 | ? !tree_int_cst_le (index, nelts) | |
2374 | : !tree_int_cst_lt (index, nelts)) | |
2375 | || tree_int_cst_sgn (index) < 0) | |
ce6a6978 | 2376 | { |
40df9099 | 2377 | diag_array_subscript (ctx, ary, index); |
ce6a6978 | 2378 | *non_constant_p = true; |
2379 | return t; | |
2380 | } | |
2381 | ||
cf3cefc9 | 2382 | if (lval && ary == oldary && index == oldidx) |
2383 | return t; | |
2384 | else if (lval) | |
2385 | return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL); | |
2386 | ||
7963b19d | 2387 | bool found; |
2388 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2389 | { | |
2390 | HOST_WIDE_INT ix = find_array_ctor_elt (ary, index); | |
2391 | found = (ix >= 0); | |
2392 | if (found) | |
2393 | i = ix; | |
aed8dc7f | 2394 | } |
7963b19d | 2395 | else |
2396 | found = (i < len); | |
aed8dc7f | 2397 | |
14869f28 | 2398 | if (found) |
2399 | { | |
2400 | tree r; | |
2401 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2402 | r = (*CONSTRUCTOR_ELTS (ary))[i].value; | |
2403 | else if (TREE_CODE (ary) == VECTOR_CST) | |
2404 | r = VECTOR_CST_ELT (ary, i); | |
14869f28 | 2405 | else |
92fe8840 | 2406 | r = extract_string_elt (ary, elem_nchars, i); |
2407 | ||
14869f28 | 2408 | if (r) |
2409 | /* Don't VERIFY_CONSTANT here. */ | |
2410 | return r; | |
09b42213 | 2411 | |
14869f28 | 2412 | /* Otherwise the element doesn't have a value yet. */ |
09b42213 | 2413 | } |
aed8dc7f | 2414 | |
14869f28 | 2415 | /* Not found. */ |
2416 | ||
2417 | if (TREE_CODE (ary) == CONSTRUCTOR | |
2418 | && CONSTRUCTOR_NO_IMPLICIT_ZERO (ary)) | |
09b42213 | 2419 | { |
14869f28 | 2420 | /* 'ary' is part of the aggregate initializer we're currently |
2421 | building; if there's no initializer for this element yet, | |
2422 | that's an error. */ | |
2423 | if (!ctx->quiet) | |
2424 | error ("accessing uninitialized array element"); | |
2425 | *non_constant_p = true; | |
2426 | return t; | |
09b42213 | 2427 | } |
14869f28 | 2428 | |
2429 | /* If it's within the array bounds but doesn't have an explicit | |
2430 | initializer, it's value-initialized. */ | |
2431 | tree val = build_value_init (elem_type, tf_warning_or_error); | |
2432 | return cxx_eval_constant_expression (ctx, val, lval, non_constant_p, | |
2433 | overflow_p); | |
09b42213 | 2434 | } |
2435 | ||
2436 | /* Subroutine of cxx_eval_constant_expression. | |
2437 | Attempt to reduce a field access of a value of class type. */ | |
2438 | ||
2439 | static tree | |
cf72f34d | 2440 | cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2441 | bool lval, |
09b42213 | 2442 | bool *non_constant_p, bool *overflow_p) |
2443 | { | |
2444 | unsigned HOST_WIDE_INT i; | |
2445 | tree field; | |
2446 | tree value; | |
2447 | tree part = TREE_OPERAND (t, 1); | |
2448 | tree orig_whole = TREE_OPERAND (t, 0); | |
cf72f34d | 2449 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2450 | lval, |
b2a43197 | 2451 | non_constant_p, overflow_p); |
cb768824 | 2452 | if (TREE_CODE (whole) == INDIRECT_REF |
2453 | && integer_zerop (TREE_OPERAND (whole, 0)) | |
2454 | && !ctx->quiet) | |
2455 | error ("dereferencing a null pointer in %qE", orig_whole); | |
2456 | ||
f16ed232 | 2457 | if (TREE_CODE (whole) == PTRMEM_CST) |
2458 | whole = cplus_expand_constant (whole); | |
09b42213 | 2459 | if (whole == orig_whole) |
2460 | return t; | |
1227ba74 | 2461 | if (lval) |
09b42213 | 2462 | return fold_build3 (COMPONENT_REF, TREE_TYPE (t), |
2463 | whole, part, NULL_TREE); | |
2464 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2465 | CONSTRUCTOR. */ | |
2466 | if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR) | |
2467 | { | |
f83e6885 | 2468 | if (!ctx->quiet) |
09b42213 | 2469 | error ("%qE is not a constant expression", orig_whole); |
2470 | *non_constant_p = true; | |
2471 | } | |
2472 | if (DECL_MUTABLE_P (part)) | |
2473 | { | |
f83e6885 | 2474 | if (!ctx->quiet) |
09b42213 | 2475 | error ("mutable %qD is not usable in a constant expression", part); |
2476 | *non_constant_p = true; | |
2477 | } | |
2478 | if (*non_constant_p) | |
2479 | return t; | |
a4360e57 | 2480 | bool pmf = TYPE_PTRMEMFUNC_P (TREE_TYPE (whole)); |
09b42213 | 2481 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) |
2482 | { | |
a4360e57 | 2483 | /* Use name match for PMF fields, as a variant will have a |
2484 | different FIELD_DECL with a different type. */ | |
2485 | if (pmf ? DECL_NAME (field) == DECL_NAME (part) | |
2486 | : field == part) | |
9c96033c | 2487 | { |
2488 | if (value) | |
2489 | return value; | |
2490 | else | |
2491 | /* We're in the middle of initializing it. */ | |
2492 | break; | |
2493 | } | |
09b42213 | 2494 | } |
2495 | if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE | |
2496 | && CONSTRUCTOR_NELTS (whole) > 0) | |
2497 | { | |
2498 | /* DR 1188 says we don't have to deal with this. */ | |
f83e6885 | 2499 | if (!ctx->quiet) |
09b42213 | 2500 | error ("accessing %qD member instead of initialized %qD member in " |
2501 | "constant expression", part, CONSTRUCTOR_ELT (whole, 0)->index); | |
2502 | *non_constant_p = true; | |
2503 | return t; | |
2504 | } | |
2505 | ||
f894a056 | 2506 | /* We only create a CONSTRUCTOR for a subobject when we modify it, so empty |
2507 | classes never get represented; throw together a value now. */ | |
2508 | if (is_really_empty_class (TREE_TYPE (t))) | |
2509 | return build_constructor (TREE_TYPE (t), NULL); | |
2510 | ||
a4360e57 | 2511 | gcc_assert (DECL_CONTEXT (part) == TYPE_MAIN_VARIANT (TREE_TYPE (whole))); |
2512 | ||
f894a056 | 2513 | if (CONSTRUCTOR_NO_IMPLICIT_ZERO (whole)) |
cf72f34d | 2514 | { |
2515 | /* 'whole' is part of the aggregate initializer we're currently | |
2516 | building; if there's no initializer for this member yet, that's an | |
f894a056 | 2517 | error. */ |
f83e6885 | 2518 | if (!ctx->quiet) |
cf72f34d | 2519 | error ("accessing uninitialized member %qD", part); |
2520 | *non_constant_p = true; | |
2521 | return t; | |
2522 | } | |
2523 | ||
09b42213 | 2524 | /* If there's no explicit init for this field, it's value-initialized. */ |
2525 | value = build_value_init (TREE_TYPE (t), tf_warning_or_error); | |
cf72f34d | 2526 | return cxx_eval_constant_expression (ctx, value, |
1227ba74 | 2527 | lval, |
b2a43197 | 2528 | non_constant_p, overflow_p); |
09b42213 | 2529 | } |
2530 | ||
2531 | /* Subroutine of cxx_eval_constant_expression. | |
2532 | Attempt to reduce a field access of a value of class type that is | |
2533 | expressed as a BIT_FIELD_REF. */ | |
2534 | ||
2535 | static tree | |
cf72f34d | 2536 | cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2537 | bool lval, |
09b42213 | 2538 | bool *non_constant_p, bool *overflow_p) |
2539 | { | |
2540 | tree orig_whole = TREE_OPERAND (t, 0); | |
2541 | tree retval, fldval, utype, mask; | |
2542 | bool fld_seen = false; | |
2543 | HOST_WIDE_INT istart, isize; | |
cf72f34d | 2544 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2545 | lval, |
b2a43197 | 2546 | non_constant_p, overflow_p); |
09b42213 | 2547 | tree start, field, value; |
2548 | unsigned HOST_WIDE_INT i; | |
2549 | ||
2550 | if (whole == orig_whole) | |
2551 | return t; | |
2552 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2553 | CONSTRUCTOR. */ | |
2554 | if (!*non_constant_p | |
2555 | && TREE_CODE (whole) != VECTOR_CST | |
2556 | && TREE_CODE (whole) != CONSTRUCTOR) | |
2557 | { | |
f83e6885 | 2558 | if (!ctx->quiet) |
09b42213 | 2559 | error ("%qE is not a constant expression", orig_whole); |
2560 | *non_constant_p = true; | |
2561 | } | |
2562 | if (*non_constant_p) | |
2563 | return t; | |
2564 | ||
2565 | if (TREE_CODE (whole) == VECTOR_CST) | |
2566 | return fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole, | |
2567 | TREE_OPERAND (t, 1), TREE_OPERAND (t, 2)); | |
2568 | ||
2569 | start = TREE_OPERAND (t, 2); | |
2570 | istart = tree_to_shwi (start); | |
2571 | isize = tree_to_shwi (TREE_OPERAND (t, 1)); | |
2572 | utype = TREE_TYPE (t); | |
2573 | if (!TYPE_UNSIGNED (utype)) | |
2574 | utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1); | |
2575 | retval = build_int_cst (utype, 0); | |
2576 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
2577 | { | |
2578 | tree bitpos = bit_position (field); | |
2579 | if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1)) | |
2580 | return value; | |
2581 | if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE | |
2582 | && TREE_CODE (value) == INTEGER_CST | |
2583 | && tree_fits_shwi_p (bitpos) | |
2584 | && tree_fits_shwi_p (DECL_SIZE (field))) | |
2585 | { | |
2586 | HOST_WIDE_INT bit = tree_to_shwi (bitpos); | |
2587 | HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field)); | |
2588 | HOST_WIDE_INT shift; | |
2589 | if (bit >= istart && bit + sz <= istart + isize) | |
2590 | { | |
2591 | fldval = fold_convert (utype, value); | |
2592 | mask = build_int_cst_type (utype, -1); | |
2593 | mask = fold_build2 (LSHIFT_EXPR, utype, mask, | |
2594 | size_int (TYPE_PRECISION (utype) - sz)); | |
2595 | mask = fold_build2 (RSHIFT_EXPR, utype, mask, | |
2596 | size_int (TYPE_PRECISION (utype) - sz)); | |
2597 | fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask); | |
2598 | shift = bit - istart; | |
2599 | if (BYTES_BIG_ENDIAN) | |
2600 | shift = TYPE_PRECISION (utype) - shift - sz; | |
2601 | fldval = fold_build2 (LSHIFT_EXPR, utype, fldval, | |
2602 | size_int (shift)); | |
2603 | retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval); | |
2604 | fld_seen = true; | |
2605 | } | |
2606 | } | |
2607 | } | |
2608 | if (fld_seen) | |
2609 | return fold_convert (TREE_TYPE (t), retval); | |
2610 | gcc_unreachable (); | |
2611 | return error_mark_node; | |
2612 | } | |
2613 | ||
2614 | /* Subroutine of cxx_eval_constant_expression. | |
2615 | Evaluate a short-circuited logical expression T in the context | |
2616 | of a given constexpr CALL. BAILOUT_VALUE is the value for | |
2617 | early return. CONTINUE_VALUE is used here purely for | |
2618 | sanity check purposes. */ | |
2619 | ||
2620 | static tree | |
cf72f34d | 2621 | cxx_eval_logical_expression (const constexpr_ctx *ctx, tree t, |
09b42213 | 2622 | tree bailout_value, tree continue_value, |
1227ba74 | 2623 | bool lval, |
09b42213 | 2624 | bool *non_constant_p, bool *overflow_p) |
2625 | { | |
2626 | tree r; | |
cf72f34d | 2627 | tree lhs = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 2628 | lval, |
b2a43197 | 2629 | non_constant_p, overflow_p); |
09b42213 | 2630 | VERIFY_CONSTANT (lhs); |
2631 | if (tree_int_cst_equal (lhs, bailout_value)) | |
2632 | return lhs; | |
2633 | gcc_assert (tree_int_cst_equal (lhs, continue_value)); | |
cf72f34d | 2634 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2635 | lval, non_constant_p, |
b2a43197 | 2636 | overflow_p); |
09b42213 | 2637 | VERIFY_CONSTANT (r); |
2638 | return r; | |
2639 | } | |
2640 | ||
2641 | /* REF is a COMPONENT_REF designating a particular field. V is a vector of | |
2642 | CONSTRUCTOR elements to initialize (part of) an object containing that | |
2643 | field. Return a pointer to the constructor_elt corresponding to the | |
2644 | initialization of the field. */ | |
2645 | ||
2646 | static constructor_elt * | |
2647 | base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref) | |
2648 | { | |
2649 | tree aggr = TREE_OPERAND (ref, 0); | |
2650 | tree field = TREE_OPERAND (ref, 1); | |
2651 | HOST_WIDE_INT i; | |
2652 | constructor_elt *ce; | |
2653 | ||
2654 | gcc_assert (TREE_CODE (ref) == COMPONENT_REF); | |
2655 | ||
2656 | if (TREE_CODE (aggr) == COMPONENT_REF) | |
2657 | { | |
2658 | constructor_elt *base_ce | |
2659 | = base_field_constructor_elt (v, aggr); | |
2660 | v = CONSTRUCTOR_ELTS (base_ce->value); | |
2661 | } | |
2662 | ||
2663 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2664 | if (ce->index == field) | |
2665 | return ce; | |
2666 | ||
2667 | gcc_unreachable (); | |
2668 | return NULL; | |
2669 | } | |
2670 | ||
cf72f34d | 2671 | /* Some of the expressions fed to the constexpr mechanism are calls to |
2672 | constructors, which have type void. In that case, return the type being | |
2673 | initialized by the constructor. */ | |
2674 | ||
2675 | static tree | |
2676 | initialized_type (tree t) | |
2677 | { | |
2678 | if (TYPE_P (t)) | |
2679 | return t; | |
2680 | tree type = cv_unqualified (TREE_TYPE (t)); | |
2681 | if (TREE_CODE (t) == CALL_EXPR || TREE_CODE (t) == AGGR_INIT_EXPR) | |
2682 | { | |
2683 | /* A constructor call has void type, so we need to look deeper. */ | |
2684 | tree fn = get_function_named_in_call (t); | |
2685 | if (fn && TREE_CODE (fn) == FUNCTION_DECL | |
2686 | && DECL_CXX_CONSTRUCTOR_P (fn)) | |
2687 | type = DECL_CONTEXT (fn); | |
2688 | } | |
2689 | return type; | |
2690 | } | |
2691 | ||
2692 | /* We're about to initialize element INDEX of an array or class from VALUE. | |
2693 | Set up NEW_CTX appropriately by adjusting .object to refer to the | |
2694 | subobject and creating a new CONSTRUCTOR if the element is itself | |
2695 | a class or array. */ | |
2696 | ||
2697 | static void | |
2698 | init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, | |
2699 | tree index, tree &value) | |
2700 | { | |
2701 | new_ctx = *ctx; | |
2702 | ||
2703 | if (index && TREE_CODE (index) != INTEGER_CST | |
2704 | && TREE_CODE (index) != FIELD_DECL) | |
2705 | /* This won't have an element in the new CONSTRUCTOR. */ | |
2706 | return; | |
2707 | ||
2708 | tree type = initialized_type (value); | |
2709 | if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) | |
2710 | /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ | |
2711 | return; | |
2712 | ||
2713 | /* The sub-aggregate initializer might contain a placeholder; | |
2714 | update object to refer to the subobject and ctor to refer to | |
2715 | the (newly created) sub-initializer. */ | |
2716 | if (ctx->object) | |
2717 | new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); | |
2718 | tree elt = build_constructor (type, NULL); | |
2719 | CONSTRUCTOR_NO_IMPLICIT_ZERO (elt) = true; | |
2720 | new_ctx.ctor = elt; | |
2721 | ||
2722 | if (TREE_CODE (value) == TARGET_EXPR) | |
2723 | /* Avoid creating another CONSTRUCTOR when we expand the TARGET_EXPR. */ | |
2724 | value = TARGET_EXPR_INITIAL (value); | |
2725 | } | |
2726 | ||
2727 | /* We're about to process an initializer for a class or array TYPE. Make | |
2728 | sure that CTX is set up appropriately. */ | |
2729 | ||
2730 | static void | |
2731 | verify_ctor_sanity (const constexpr_ctx *ctx, tree type) | |
2732 | { | |
2733 | /* We don't bother building a ctor for an empty base subobject. */ | |
2734 | if (is_empty_class (type)) | |
2735 | return; | |
2736 | ||
2737 | /* We're in the middle of an initializer that might involve placeholders; | |
2738 | our caller should have created a CONSTRUCTOR for us to put the | |
2739 | initializer into. We will either return that constructor or T. */ | |
2740 | gcc_assert (ctx->ctor); | |
2741 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2742 | (type, TREE_TYPE (ctx->ctor))); | |
bbf58224 | 2743 | /* We used to check that ctx->ctor was empty, but that isn't the case when |
2744 | the object is zero-initialized before calling the constructor. */ | |
cf72f34d | 2745 | if (ctx->object) |
d9751a3c | 2746 | { |
2747 | tree otype = TREE_TYPE (ctx->object); | |
2748 | gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, otype) | |
2749 | /* Handle flexible array members. */ | |
2750 | || (TREE_CODE (otype) == ARRAY_TYPE | |
2751 | && TYPE_DOMAIN (otype) == NULL_TREE | |
2752 | && TREE_CODE (type) == ARRAY_TYPE | |
2753 | && (same_type_ignoring_top_level_qualifiers_p | |
2754 | (TREE_TYPE (type), TREE_TYPE (otype))))); | |
2755 | } | |
cf72f34d | 2756 | gcc_assert (!ctx->object || !DECL_P (ctx->object) |
2757 | || *(ctx->values->get (ctx->object)) == ctx->ctor); | |
2758 | } | |
2759 | ||
09b42213 | 2760 | /* Subroutine of cxx_eval_constant_expression. |
2761 | The expression tree T denotes a C-style array or a C-style | |
2762 | aggregate. Reduce it to a constant expression. */ | |
2763 | ||
2764 | static tree | |
cf72f34d | 2765 | cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2766 | bool lval, |
09b42213 | 2767 | bool *non_constant_p, bool *overflow_p) |
2768 | { | |
2769 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
09b42213 | 2770 | bool changed = false; |
2771 | gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t)); | |
68464393 | 2772 | tree type = TREE_TYPE (t); |
cf72f34d | 2773 | |
68464393 | 2774 | constexpr_ctx new_ctx; |
d2dd85e3 | 2775 | if (TYPE_PTRMEMFUNC_P (type) || VECTOR_TYPE_P (type)) |
68464393 | 2776 | { |
d2dd85e3 | 2777 | /* We don't really need the ctx->ctor business for a PMF or |
2778 | vector, but it's simpler to use the same code. */ | |
68464393 | 2779 | new_ctx = *ctx; |
2780 | new_ctx.ctor = build_constructor (type, NULL); | |
2781 | new_ctx.object = NULL_TREE; | |
2782 | ctx = &new_ctx; | |
2783 | }; | |
2784 | verify_ctor_sanity (ctx, type); | |
cf72f34d | 2785 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); |
2786 | vec_alloc (*p, vec_safe_length (v)); | |
2787 | ||
58b0f9ce | 2788 | unsigned i; |
2789 | tree index, value; | |
2790 | bool constant_p = true; | |
2791 | bool side_effects_p = false; | |
cf72f34d | 2792 | FOR_EACH_CONSTRUCTOR_ELT (v, i, index, value) |
09b42213 | 2793 | { |
5ae773e4 | 2794 | tree orig_value = value; |
cf72f34d | 2795 | init_subob_ctx (ctx, new_ctx, index, value); |
2796 | if (new_ctx.ctor != ctx->ctor) | |
2797 | /* If we built a new CONSTRUCTOR, attach it now so that other | |
2798 | initializers can refer to it. */ | |
2799 | CONSTRUCTOR_APPEND_ELT (*p, index, new_ctx.ctor); | |
2800 | tree elt = cxx_eval_constant_expression (&new_ctx, value, | |
1227ba74 | 2801 | lval, |
b2a43197 | 2802 | non_constant_p, overflow_p); |
09b42213 | 2803 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 2804 | if (ctx->quiet && *non_constant_p) |
cf72f34d | 2805 | break; |
5ae773e4 | 2806 | if (elt != orig_value) |
09b42213 | 2807 | changed = true; |
58b0f9ce | 2808 | |
2809 | if (!TREE_CONSTANT (elt)) | |
2810 | constant_p = false; | |
2811 | if (TREE_SIDE_EFFECTS (elt)) | |
2812 | side_effects_p = true; | |
cf72f34d | 2813 | if (index && TREE_CODE (index) == COMPONENT_REF) |
09b42213 | 2814 | { |
2815 | /* This is an initialization of a vfield inside a base | |
2816 | subaggregate that we already initialized; push this | |
2817 | initialization into the previous initialization. */ | |
cf72f34d | 2818 | constructor_elt *inner = base_field_constructor_elt (*p, index); |
09b42213 | 2819 | inner->value = elt; |
cf72f34d | 2820 | changed = true; |
09b42213 | 2821 | } |
cf72f34d | 2822 | else if (index |
2823 | && (TREE_CODE (index) == NOP_EXPR | |
2824 | || TREE_CODE (index) == POINTER_PLUS_EXPR)) | |
09b42213 | 2825 | { |
2826 | /* This is an initializer for an empty base; now that we've | |
2827 | checked that it's constant, we can ignore it. */ | |
cf72f34d | 2828 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (index)))); |
2829 | changed = true; | |
2830 | } | |
2831 | else if (new_ctx.ctor != ctx->ctor) | |
2832 | { | |
2833 | /* We appended this element above; update the value. */ | |
2834 | gcc_assert ((*p)->last().index == index); | |
2835 | (*p)->last().value = elt; | |
09b42213 | 2836 | } |
2837 | else | |
cf72f34d | 2838 | CONSTRUCTOR_APPEND_ELT (*p, index, elt); |
09b42213 | 2839 | } |
2840 | if (*non_constant_p || !changed) | |
cf72f34d | 2841 | return t; |
2842 | t = ctx->ctor; | |
2843 | /* We're done building this CONSTRUCTOR, so now we can interpret an | |
2844 | element without an explicit initializer as value-initialized. */ | |
2845 | CONSTRUCTOR_NO_IMPLICIT_ZERO (t) = false; | |
58b0f9ce | 2846 | TREE_CONSTANT (t) = constant_p; |
2847 | TREE_SIDE_EFFECTS (t) = side_effects_p; | |
68464393 | 2848 | if (VECTOR_TYPE_P (type)) |
09b42213 | 2849 | t = fold (t); |
2850 | return t; | |
2851 | } | |
2852 | ||
2853 | /* Subroutine of cxx_eval_constant_expression. | |
2854 | The expression tree T is a VEC_INIT_EXPR which denotes the desired | |
2855 | initialization of a non-static data member of array type. Reduce it to a | |
2856 | CONSTRUCTOR. | |
2857 | ||
2858 | Note that apart from value-initialization (when VALUE_INIT is true), | |
2859 | this is only intended to support value-initialization and the | |
2860 | initializations done by defaulted constructors for classes with | |
2861 | non-static data members of array type. In this case, VEC_INIT_EXPR_INIT | |
2862 | will either be NULL_TREE for the default constructor, or a COMPONENT_REF | |
2863 | for the copy/move constructor. */ | |
2864 | ||
2865 | static tree | |
cf72f34d | 2866 | cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, |
1227ba74 | 2867 | bool value_init, bool lval, |
09b42213 | 2868 | bool *non_constant_p, bool *overflow_p) |
2869 | { | |
2870 | tree elttype = TREE_TYPE (atype); | |
3e520b97 | 2871 | unsigned HOST_WIDE_INT max = tree_to_uhwi (array_type_nelts_top (atype)); |
cf72f34d | 2872 | verify_ctor_sanity (ctx, atype); |
2873 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
2874 | vec_alloc (*p, max + 1); | |
09b42213 | 2875 | bool pre_init = false; |
3e520b97 | 2876 | unsigned HOST_WIDE_INT i; |
09b42213 | 2877 | |
2878 | /* For the default constructor, build up a call to the default | |
2879 | constructor of the element type. We only need to handle class types | |
2880 | here, as for a constructor to be constexpr, all members must be | |
2881 | initialized, which for a defaulted default constructor means they must | |
2882 | be of a class type with a constexpr default constructor. */ | |
2883 | if (TREE_CODE (elttype) == ARRAY_TYPE) | |
2884 | /* We only do this at the lowest level. */; | |
2885 | else if (value_init) | |
2886 | { | |
2887 | init = build_value_init (elttype, tf_warning_or_error); | |
09b42213 | 2888 | pre_init = true; |
2889 | } | |
2890 | else if (!init) | |
2891 | { | |
2892 | vec<tree, va_gc> *argvec = make_tree_vector (); | |
2893 | init = build_special_member_call (NULL_TREE, complete_ctor_identifier, | |
2894 | &argvec, elttype, LOOKUP_NORMAL, | |
2895 | tf_warning_or_error); | |
2896 | release_tree_vector (argvec); | |
9c96033c | 2897 | init = build_aggr_init_expr (TREE_TYPE (init), init); |
09b42213 | 2898 | pre_init = true; |
2899 | } | |
2900 | ||
3e520b97 | 2901 | for (i = 0; i < max; ++i) |
09b42213 | 2902 | { |
2903 | tree idx = build_int_cst (size_type_node, i); | |
2904 | tree eltinit; | |
d9377ad5 | 2905 | bool reuse = false; |
cf72f34d | 2906 | constexpr_ctx new_ctx; |
2907 | init_subob_ctx (ctx, new_ctx, idx, pre_init ? init : elttype); | |
2908 | if (new_ctx.ctor != ctx->ctor) | |
2909 | CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor); | |
09b42213 | 2910 | if (TREE_CODE (elttype) == ARRAY_TYPE) |
2911 | { | |
2912 | /* A multidimensional array; recurse. */ | |
2913 | if (value_init || init == NULL_TREE) | |
d9377ad5 | 2914 | { |
2915 | eltinit = NULL_TREE; | |
2916 | reuse = i == 0; | |
2917 | } | |
09b42213 | 2918 | else |
2919 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2920 | tf_warning_or_error); | |
cf72f34d | 2921 | eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, value_init, |
1227ba74 | 2922 | lval, |
09b42213 | 2923 | non_constant_p, overflow_p); |
2924 | } | |
2925 | else if (pre_init) | |
2926 | { | |
2927 | /* Initializing an element using value or default initialization | |
2928 | we just pre-built above. */ | |
d9377ad5 | 2929 | eltinit = cxx_eval_constant_expression (&new_ctx, init, lval, |
2930 | non_constant_p, overflow_p); | |
2931 | reuse = i == 0; | |
09b42213 | 2932 | } |
2933 | else | |
2934 | { | |
2935 | /* Copying an element. */ | |
2936 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2937 | (atype, TREE_TYPE (init))); | |
2938 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2939 | tf_warning_or_error); | |
18bede74 | 2940 | if (!lvalue_p (init)) |
09b42213 | 2941 | eltinit = move (eltinit); |
2942 | eltinit = force_rvalue (eltinit, tf_warning_or_error); | |
cf72f34d | 2943 | eltinit = (cxx_eval_constant_expression |
1227ba74 | 2944 | (&new_ctx, eltinit, lval, |
b2a43197 | 2945 | non_constant_p, overflow_p)); |
09b42213 | 2946 | } |
f83e6885 | 2947 | if (*non_constant_p && !ctx->quiet) |
cf72f34d | 2948 | break; |
2949 | if (new_ctx.ctor != ctx->ctor) | |
2950 | { | |
2951 | /* We appended this element above; update the value. */ | |
2952 | gcc_assert ((*p)->last().index == idx); | |
2953 | (*p)->last().value = eltinit; | |
2954 | } | |
2955 | else | |
2956 | CONSTRUCTOR_APPEND_ELT (*p, idx, eltinit); | |
d9377ad5 | 2957 | /* Reuse the result of cxx_eval_constant_expression call |
2958 | from the first iteration to all others if it is a constant | |
2959 | initializer that doesn't require relocations. */ | |
2960 | if (reuse | |
2961 | && max > 1 | |
2962 | && (initializer_constant_valid_p (eltinit, TREE_TYPE (eltinit)) | |
2963 | == null_pointer_node)) | |
2964 | { | |
2965 | if (new_ctx.ctor != ctx->ctor) | |
2966 | eltinit = new_ctx.ctor; | |
2967 | for (i = 1; i < max; ++i) | |
2968 | { | |
2969 | idx = build_int_cst (size_type_node, i); | |
e283bb4f | 2970 | CONSTRUCTOR_APPEND_ELT (*p, idx, unshare_constructor (eltinit)); |
d9377ad5 | 2971 | } |
2972 | break; | |
2973 | } | |
09b42213 | 2974 | } |
2975 | ||
2976 | if (!*non_constant_p) | |
2977 | { | |
cf72f34d | 2978 | init = ctx->ctor; |
2979 | CONSTRUCTOR_NO_IMPLICIT_ZERO (init) = false; | |
09b42213 | 2980 | } |
09b42213 | 2981 | return init; |
2982 | } | |
2983 | ||
2984 | static tree | |
cf72f34d | 2985 | cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2986 | bool lval, |
09b42213 | 2987 | bool *non_constant_p, bool *overflow_p) |
2988 | { | |
2989 | tree atype = TREE_TYPE (t); | |
2990 | tree init = VEC_INIT_EXPR_INIT (t); | |
cf72f34d | 2991 | tree r = cxx_eval_vec_init_1 (ctx, atype, init, |
09b42213 | 2992 | VEC_INIT_EXPR_VALUE_INIT (t), |
1227ba74 | 2993 | lval, non_constant_p, overflow_p); |
09b42213 | 2994 | if (*non_constant_p) |
2995 | return t; | |
2996 | else | |
2997 | return r; | |
2998 | } | |
2999 | ||
3000 | /* A less strict version of fold_indirect_ref_1, which requires cv-quals to | |
3001 | match. We want to be less strict for simple *& folding; if we have a | |
3002 | non-const temporary that we access through a const pointer, that should | |
3003 | work. We handle this here rather than change fold_indirect_ref_1 | |
3004 | because we're dealing with things like ADDR_EXPR of INTEGER_CST which | |
3005 | don't really make sense outside of constant expression evaluation. Also | |
3006 | we want to allow folding to COMPONENT_REF, which could cause trouble | |
3007 | with TBAA in fold_indirect_ref_1. | |
3008 | ||
3009 | Try to keep this function synced with fold_indirect_ref_1. */ | |
3010 | ||
3011 | static tree | |
3012 | cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) | |
3013 | { | |
3014 | tree sub, subtype; | |
3015 | ||
3016 | sub = op0; | |
3017 | STRIP_NOPS (sub); | |
3018 | subtype = TREE_TYPE (sub); | |
3019 | if (!POINTER_TYPE_P (subtype)) | |
3020 | return NULL_TREE; | |
3021 | ||
3022 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3023 | { | |
3024 | tree op = TREE_OPERAND (sub, 0); | |
3025 | tree optype = TREE_TYPE (op); | |
3026 | ||
3027 | /* *&CONST_DECL -> to the value of the const decl. */ | |
3028 | if (TREE_CODE (op) == CONST_DECL) | |
3029 | return DECL_INITIAL (op); | |
3030 | /* *&p => p; make sure to handle *&"str"[cst] here. */ | |
c4118b0c | 3031 | if (same_type_ignoring_top_level_qualifiers_p (optype, type) |
3032 | /* Also handle the case where the desired type is an array of unknown | |
3033 | bounds because the variable has had its bounds deduced since the | |
3034 | ADDR_EXPR was created. */ | |
3035 | || (TREE_CODE (type) == ARRAY_TYPE | |
3036 | && TREE_CODE (optype) == ARRAY_TYPE | |
3037 | && TYPE_DOMAIN (type) == NULL_TREE | |
3038 | && same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (optype), | |
3039 | TREE_TYPE (type)))) | |
09b42213 | 3040 | { |
3041 | tree fop = fold_read_from_constant_string (op); | |
3042 | if (fop) | |
3043 | return fop; | |
3044 | else | |
3045 | return op; | |
3046 | } | |
3047 | /* *(foo *)&fooarray => fooarray[0] */ | |
3048 | else if (TREE_CODE (optype) == ARRAY_TYPE | |
3049 | && (same_type_ignoring_top_level_qualifiers_p | |
3050 | (type, TREE_TYPE (optype)))) | |
3051 | { | |
3052 | tree type_domain = TYPE_DOMAIN (optype); | |
3053 | tree min_val = size_zero_node; | |
3054 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3055 | min_val = TYPE_MIN_VALUE (type_domain); | |
3056 | return build4_loc (loc, ARRAY_REF, type, op, min_val, | |
3057 | NULL_TREE, NULL_TREE); | |
3058 | } | |
3059 | /* *(foo *)&complexfoo => __real__ complexfoo */ | |
3060 | else if (TREE_CODE (optype) == COMPLEX_TYPE | |
3061 | && (same_type_ignoring_top_level_qualifiers_p | |
3062 | (type, TREE_TYPE (optype)))) | |
3063 | return fold_build1_loc (loc, REALPART_EXPR, type, op); | |
3064 | /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3065 | else if (VECTOR_TYPE_P (optype) |
09b42213 | 3066 | && (same_type_ignoring_top_level_qualifiers_p |
3067 | (type, TREE_TYPE (optype)))) | |
3068 | { | |
3069 | tree part_width = TYPE_SIZE (type); | |
3070 | tree index = bitsize_int (0); | |
3071 | return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, index); | |
3072 | } | |
3073 | /* Also handle conversion to an empty base class, which | |
3074 | is represented with a NOP_EXPR. */ | |
3075 | else if (is_empty_class (type) | |
3076 | && CLASS_TYPE_P (optype) | |
3077 | && DERIVED_FROM_P (type, optype)) | |
3078 | { | |
3079 | *empty_base = true; | |
3080 | return op; | |
3081 | } | |
3082 | /* *(foo *)&struct_with_foo_field => COMPONENT_REF */ | |
3083 | else if (RECORD_OR_UNION_TYPE_P (optype)) | |
3084 | { | |
3085 | tree field = TYPE_FIELDS (optype); | |
3086 | for (; field; field = DECL_CHAIN (field)) | |
3087 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3088 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3089 | && integer_zerop (byte_position (field)) |
3090 | && (same_type_ignoring_top_level_qualifiers_p | |
3091 | (TREE_TYPE (field), type))) | |
a48667ee | 3092 | return fold_build3 (COMPONENT_REF, type, op, field, NULL_TREE); |
09b42213 | 3093 | } |
3094 | } | |
3095 | else if (TREE_CODE (sub) == POINTER_PLUS_EXPR | |
3096 | && TREE_CODE (TREE_OPERAND (sub, 1)) == INTEGER_CST) | |
3097 | { | |
3098 | tree op00 = TREE_OPERAND (sub, 0); | |
3099 | tree op01 = TREE_OPERAND (sub, 1); | |
3100 | ||
3101 | STRIP_NOPS (op00); | |
3102 | if (TREE_CODE (op00) == ADDR_EXPR) | |
3103 | { | |
3104 | tree op00type; | |
3105 | op00 = TREE_OPERAND (op00, 0); | |
3106 | op00type = TREE_TYPE (op00); | |
3107 | ||
3108 | /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3109 | if (VECTOR_TYPE_P (op00type) |
09b42213 | 3110 | && (same_type_ignoring_top_level_qualifiers_p |
3111 | (type, TREE_TYPE (op00type)))) | |
3112 | { | |
3113 | HOST_WIDE_INT offset = tree_to_shwi (op01); | |
3114 | tree part_width = TYPE_SIZE (type); | |
3115 | unsigned HOST_WIDE_INT part_widthi = tree_to_shwi (part_width)/BITS_PER_UNIT; | |
3116 | unsigned HOST_WIDE_INT indexi = offset * BITS_PER_UNIT; | |
3117 | tree index = bitsize_int (indexi); | |
3118 | ||
3119 | if (offset / part_widthi < TYPE_VECTOR_SUBPARTS (op00type)) | |
3120 | return fold_build3_loc (loc, | |
3121 | BIT_FIELD_REF, type, op00, | |
3122 | part_width, index); | |
3123 | ||
3124 | } | |
3125 | /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ | |
3126 | else if (TREE_CODE (op00type) == COMPLEX_TYPE | |
3127 | && (same_type_ignoring_top_level_qualifiers_p | |
3128 | (type, TREE_TYPE (op00type)))) | |
3129 | { | |
3130 | tree size = TYPE_SIZE_UNIT (type); | |
3131 | if (tree_int_cst_equal (size, op01)) | |
3132 | return fold_build1_loc (loc, IMAGPART_EXPR, type, op00); | |
3133 | } | |
3134 | /* ((foo *)&fooarray)[1] => fooarray[1] */ | |
3135 | else if (TREE_CODE (op00type) == ARRAY_TYPE | |
3136 | && (same_type_ignoring_top_level_qualifiers_p | |
3137 | (type, TREE_TYPE (op00type)))) | |
3138 | { | |
3139 | tree type_domain = TYPE_DOMAIN (op00type); | |
3140 | tree min_val = size_zero_node; | |
3141 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3142 | min_val = TYPE_MIN_VALUE (type_domain); | |
3143 | op01 = size_binop_loc (loc, EXACT_DIV_EXPR, op01, | |
3144 | TYPE_SIZE_UNIT (type)); | |
3145 | op01 = size_binop_loc (loc, PLUS_EXPR, op01, min_val); | |
3146 | return build4_loc (loc, ARRAY_REF, type, op00, op01, | |
3147 | NULL_TREE, NULL_TREE); | |
3148 | } | |
3149 | /* Also handle conversion to an empty base class, which | |
3150 | is represented with a NOP_EXPR. */ | |
3151 | else if (is_empty_class (type) | |
3152 | && CLASS_TYPE_P (op00type) | |
3153 | && DERIVED_FROM_P (type, op00type)) | |
3154 | { | |
3155 | *empty_base = true; | |
3156 | return op00; | |
3157 | } | |
3158 | /* ((foo *)&struct_with_foo_field)[1] => COMPONENT_REF */ | |
3159 | else if (RECORD_OR_UNION_TYPE_P (op00type)) | |
3160 | { | |
3161 | tree field = TYPE_FIELDS (op00type); | |
3162 | for (; field; field = DECL_CHAIN (field)) | |
3163 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3164 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3165 | && tree_int_cst_equal (byte_position (field), op01) |
3166 | && (same_type_ignoring_top_level_qualifiers_p | |
3167 | (TREE_TYPE (field), type))) | |
a48667ee | 3168 | return fold_build3 (COMPONENT_REF, type, op00, |
3169 | field, NULL_TREE); | |
09b42213 | 3170 | } |
3171 | } | |
3172 | } | |
3173 | /* *(foo *)fooarrptr => (*fooarrptr)[0] */ | |
3174 | else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE | |
3175 | && (same_type_ignoring_top_level_qualifiers_p | |
3176 | (type, TREE_TYPE (TREE_TYPE (subtype))))) | |
3177 | { | |
3178 | tree type_domain; | |
3179 | tree min_val = size_zero_node; | |
3180 | tree newsub = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL); | |
3181 | if (newsub) | |
3182 | sub = newsub; | |
3183 | else | |
3184 | sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub); | |
3185 | type_domain = TYPE_DOMAIN (TREE_TYPE (sub)); | |
3186 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3187 | min_val = TYPE_MIN_VALUE (type_domain); | |
3188 | return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE, | |
3189 | NULL_TREE); | |
3190 | } | |
3191 | ||
3192 | return NULL_TREE; | |
3193 | } | |
3194 | ||
3195 | static tree | |
cf72f34d | 3196 | cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3197 | bool lval, |
09b42213 | 3198 | bool *non_constant_p, bool *overflow_p) |
3199 | { | |
3200 | tree orig_op0 = TREE_OPERAND (t, 0); | |
09b42213 | 3201 | bool empty_base = false; |
09b42213 | 3202 | |
d2c63826 | 3203 | /* We can handle a MEM_REF like an INDIRECT_REF, if MEM_REF's second |
3204 | operand is an integer-zero. Otherwise reject the MEM_REF for now. */ | |
3205 | ||
3206 | if (TREE_CODE (t) == MEM_REF | |
3207 | && (!TREE_OPERAND (t, 1) || !integer_zerop (TREE_OPERAND (t, 1)))) | |
3208 | { | |
3209 | gcc_assert (ctx->quiet); | |
3210 | *non_constant_p = true; | |
3211 | return t; | |
3212 | } | |
3213 | ||
7e0f3388 | 3214 | /* First try to simplify it directly. */ |
3215 | tree r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), orig_op0, | |
3216 | &empty_base); | |
3217 | if (!r) | |
09b42213 | 3218 | { |
7e0f3388 | 3219 | /* If that didn't work, evaluate the operand first. */ |
3220 | tree op0 = cxx_eval_constant_expression (ctx, orig_op0, | |
3221 | /*lval*/false, non_constant_p, | |
3222 | overflow_p); | |
3223 | /* Don't VERIFY_CONSTANT here. */ | |
3224 | if (*non_constant_p) | |
3225 | return t; | |
3226 | ||
cb768824 | 3227 | if (!lval && integer_zerop (op0)) |
3228 | { | |
3229 | if (!ctx->quiet) | |
3230 | error ("dereferencing a null pointer"); | |
3231 | *non_constant_p = true; | |
3232 | return t; | |
3233 | } | |
3234 | ||
7e0f3388 | 3235 | r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), op0, |
3236 | &empty_base); | |
3237 | if (r == NULL_TREE) | |
09b42213 | 3238 | { |
3239 | /* We couldn't fold to a constant value. Make sure it's not | |
3240 | something we should have been able to fold. */ | |
7e0f3388 | 3241 | tree sub = op0; |
3242 | STRIP_NOPS (sub); | |
3243 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3244 | { | |
3245 | gcc_assert (!same_type_ignoring_top_level_qualifiers_p | |
3246 | (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t))); | |
3247 | /* DR 1188 says we don't have to deal with this. */ | |
3248 | if (!ctx->quiet) | |
3249 | error ("accessing value of %qE through a %qT glvalue in a " | |
3250 | "constant expression", build_fold_indirect_ref (sub), | |
3251 | TREE_TYPE (t)); | |
3252 | *non_constant_p = true; | |
3253 | return t; | |
3254 | } | |
3255 | ||
3256 | if (lval && op0 != orig_op0) | |
3257 | return build1 (INDIRECT_REF, TREE_TYPE (t), op0); | |
3258 | if (!lval) | |
3259 | VERIFY_CONSTANT (t); | |
09b42213 | 3260 | return t; |
3261 | } | |
3262 | } | |
3263 | ||
7e0f3388 | 3264 | r = cxx_eval_constant_expression (ctx, r, |
3265 | lval, non_constant_p, overflow_p); | |
3266 | if (*non_constant_p) | |
3267 | return t; | |
3268 | ||
ce4ffd9e | 3269 | /* If we're pulling out the value of an empty base, just return an empty |
09b42213 | 3270 | CONSTRUCTOR. */ |
1227ba74 | 3271 | if (empty_base && !lval) |
09b42213 | 3272 | { |
09b42213 | 3273 | r = build_constructor (TREE_TYPE (t), NULL); |
3274 | TREE_CONSTANT (r) = true; | |
3275 | } | |
3276 | ||
09b42213 | 3277 | return r; |
3278 | } | |
3279 | ||
3280 | /* Complain about R, a VAR_DECL, not being usable in a constant expression. | |
3281 | Shared between potential_constant_expression and | |
3282 | cxx_eval_constant_expression. */ | |
3283 | ||
3284 | static void | |
3285 | non_const_var_error (tree r) | |
3286 | { | |
3287 | tree type = TREE_TYPE (r); | |
3288 | error ("the value of %qD is not usable in a constant " | |
3289 | "expression", r); | |
3290 | /* Avoid error cascade. */ | |
3291 | if (DECL_INITIAL (r) == error_mark_node) | |
3292 | return; | |
3293 | if (DECL_DECLARED_CONSTEXPR_P (r)) | |
3294 | inform (DECL_SOURCE_LOCATION (r), | |
3295 | "%qD used in its own initializer", r); | |
3296 | else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) | |
3297 | { | |
3298 | if (!CP_TYPE_CONST_P (type)) | |
3299 | inform (DECL_SOURCE_LOCATION (r), | |
3300 | "%q#D is not const", r); | |
3301 | else if (CP_TYPE_VOLATILE_P (type)) | |
3302 | inform (DECL_SOURCE_LOCATION (r), | |
3303 | "%q#D is volatile", r); | |
3304 | else if (!DECL_INITIAL (r) | |
c8e3e744 | 3305 | || !TREE_CONSTANT (DECL_INITIAL (r)) |
3306 | || !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (r)) | |
09b42213 | 3307 | inform (DECL_SOURCE_LOCATION (r), |
3308 | "%qD was not initialized with a constant " | |
3309 | "expression", r); | |
3310 | else | |
3311 | gcc_unreachable (); | |
3312 | } | |
ac6641ca | 3313 | else if (TREE_CODE (type) == REFERENCE_TYPE) |
3314 | inform (DECL_SOURCE_LOCATION (r), | |
3315 | "%qD was not initialized with a constant " | |
3316 | "expression", r); | |
09b42213 | 3317 | else |
3318 | { | |
3319 | if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r)) | |
3320 | inform (DECL_SOURCE_LOCATION (r), | |
3321 | "%qD was not declared %<constexpr%>", r); | |
3322 | else | |
3323 | inform (DECL_SOURCE_LOCATION (r), | |
3324 | "%qD does not have integral or enumeration type", | |
3325 | r); | |
3326 | } | |
3327 | } | |
3328 | ||
3329 | /* Subroutine of cxx_eval_constant_expression. | |
3330 | Like cxx_eval_unary_expression, except for trinary expressions. */ | |
3331 | ||
3332 | static tree | |
cf72f34d | 3333 | cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3334 | bool lval, |
09b42213 | 3335 | bool *non_constant_p, bool *overflow_p) |
3336 | { | |
3337 | int i; | |
3338 | tree args[3]; | |
3339 | tree val; | |
3340 | ||
3341 | for (i = 0; i < 3; i++) | |
3342 | { | |
cf72f34d | 3343 | args[i] = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, i), |
1227ba74 | 3344 | lval, |
b2a43197 | 3345 | non_constant_p, overflow_p); |
09b42213 | 3346 | VERIFY_CONSTANT (args[i]); |
3347 | } | |
3348 | ||
3349 | val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t), | |
3350 | args[0], args[1], args[2]); | |
3351 | if (val == NULL_TREE) | |
3352 | return t; | |
3353 | VERIFY_CONSTANT (val); | |
3354 | return val; | |
3355 | } | |
3356 | ||
33603066 | 3357 | /* True if T was declared in a function declared to be constexpr, and |
3358 | therefore potentially constant in C++14. */ | |
3359 | ||
09b42213 | 3360 | bool |
3361 | var_in_constexpr_fn (tree t) | |
3362 | { | |
3363 | tree ctx = DECL_CONTEXT (t); | |
33603066 | 3364 | return (ctx && TREE_CODE (ctx) == FUNCTION_DECL |
09b42213 | 3365 | && DECL_DECLARED_CONSTEXPR_P (ctx)); |
3366 | } | |
3367 | ||
33603066 | 3368 | /* True if T was declared in a function that might be constexpr: either a |
3369 | function that was declared constexpr, or a C++17 lambda op(). */ | |
3370 | ||
3371 | bool | |
3372 | var_in_maybe_constexpr_fn (tree t) | |
3373 | { | |
40e2decb | 3374 | if (cxx_dialect >= cxx17 |
33603066 | 3375 | && DECL_FUNCTION_SCOPE_P (t) |
3376 | && LAMBDA_FUNCTION_P (DECL_CONTEXT (t))) | |
3377 | return true; | |
3378 | return var_in_constexpr_fn (t); | |
3379 | } | |
3380 | ||
93312944 | 3381 | /* We're assigning INIT to TARGET. In do_build_copy_constructor and |
3382 | build_over_call we implement trivial copy of a class with tail padding using | |
3383 | assignment of character arrays, which is valid in normal code, but not in | |
3384 | constexpr evaluation. We don't need to worry about clobbering tail padding | |
3385 | in constexpr evaluation, so strip the type punning. */ | |
3386 | ||
3387 | static void | |
3388 | maybe_simplify_trivial_copy (tree &target, tree &init) | |
3389 | { | |
3390 | if (TREE_CODE (target) == MEM_REF | |
3391 | && TREE_CODE (init) == MEM_REF | |
3392 | && TREE_TYPE (target) == TREE_TYPE (init) | |
3393 | && TREE_CODE (TREE_TYPE (target)) == ARRAY_TYPE | |
3394 | && TREE_TYPE (TREE_TYPE (target)) == unsigned_char_type_node) | |
3395 | { | |
3396 | target = build_fold_indirect_ref (TREE_OPERAND (target, 0)); | |
3397 | init = build_fold_indirect_ref (TREE_OPERAND (init, 0)); | |
3398 | } | |
3399 | } | |
3400 | ||
9c96033c | 3401 | /* Evaluate an INIT_EXPR or MODIFY_EXPR. */ |
3402 | ||
3403 | static tree | |
3404 | cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3405 | bool lval, |
9c96033c | 3406 | bool *non_constant_p, bool *overflow_p) |
3407 | { | |
3408 | constexpr_ctx new_ctx = *ctx; | |
3409 | ||
8a36d0ec | 3410 | tree init = TREE_OPERAND (t, 1); |
3411 | if (TREE_CLOBBER_P (init)) | |
3412 | /* Just ignore clobbers. */ | |
3413 | return void_node; | |
3414 | ||
9c96033c | 3415 | /* First we figure out where we're storing to. */ |
3416 | tree target = TREE_OPERAND (t, 0); | |
93312944 | 3417 | |
3418 | maybe_simplify_trivial_copy (target, init); | |
3419 | ||
9db9fc38 | 3420 | tree type = TREE_TYPE (target); |
9c96033c | 3421 | target = cxx_eval_constant_expression (ctx, target, |
f83e6885 | 3422 | true, |
b2a43197 | 3423 | non_constant_p, overflow_p); |
9c96033c | 3424 | if (*non_constant_p) |
3425 | return t; | |
3426 | ||
cf3cefc9 | 3427 | /* cxx_eval_array_reference for lval = true allows references one past |
3428 | end of array, because it does not know if it is just taking address | |
3429 | (which is valid), or actual dereference. Here we know it is | |
3430 | a dereference, so diagnose it here. */ | |
3431 | for (tree probe = target; probe; ) | |
3432 | { | |
3433 | switch (TREE_CODE (probe)) | |
3434 | { | |
3435 | case ARRAY_REF: | |
3436 | tree nelts, ary; | |
3437 | ary = TREE_OPERAND (probe, 0); | |
3438 | if (TREE_CODE (TREE_TYPE (ary)) == ARRAY_TYPE) | |
3439 | nelts = array_type_nelts_top (TREE_TYPE (ary)); | |
3440 | else if (VECTOR_TYPE_P (TREE_TYPE (ary))) | |
3441 | nelts = size_int (TYPE_VECTOR_SUBPARTS (TREE_TYPE (ary))); | |
3442 | else | |
3443 | gcc_unreachable (); | |
3444 | nelts = cxx_eval_constant_expression (ctx, nelts, false, | |
3445 | non_constant_p, overflow_p); | |
3446 | VERIFY_CONSTANT (nelts); | |
3447 | gcc_assert (TREE_CODE (nelts) == INTEGER_CST | |
3448 | && TREE_CODE (TREE_OPERAND (probe, 1)) == INTEGER_CST); | |
cb7bca5f | 3449 | if (wi::to_widest (TREE_OPERAND (probe, 1)) == wi::to_widest (nelts)) |
cf3cefc9 | 3450 | { |
3451 | diag_array_subscript (ctx, ary, TREE_OPERAND (probe, 1)); | |
3452 | *non_constant_p = true; | |
3453 | return t; | |
3454 | } | |
3455 | /* FALLTHRU */ | |
3456 | ||
3457 | case BIT_FIELD_REF: | |
3458 | case COMPONENT_REF: | |
3459 | probe = TREE_OPERAND (probe, 0); | |
3460 | continue; | |
3461 | ||
3462 | default: | |
3463 | probe = NULL_TREE; | |
3464 | continue; | |
3465 | } | |
3466 | } | |
3467 | ||
9db9fc38 | 3468 | if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (target), type)) |
3469 | { | |
3470 | /* For initialization of an empty base, the original target will be | |
3471 | *(base*)this, which the above evaluation resolves to the object | |
3472 | argument, which has the derived type rather than the base type. In | |
3473 | this situation, just evaluate the initializer and return, since | |
3474 | there's no actual data to store. */ | |
3475 | gcc_assert (is_empty_class (type)); | |
3476 | return cxx_eval_constant_expression (ctx, init, false, | |
3477 | non_constant_p, overflow_p); | |
3478 | } | |
3479 | ||
9c96033c | 3480 | /* And then find the underlying variable. */ |
3481 | vec<tree,va_gc> *refs = make_tree_vector(); | |
3482 | tree object = NULL_TREE; | |
3483 | for (tree probe = target; object == NULL_TREE; ) | |
3484 | { | |
3485 | switch (TREE_CODE (probe)) | |
3486 | { | |
3487 | case BIT_FIELD_REF: | |
3488 | case COMPONENT_REF: | |
3489 | case ARRAY_REF: | |
3490 | vec_safe_push (refs, TREE_OPERAND (probe, 1)); | |
3491 | vec_safe_push (refs, TREE_TYPE (probe)); | |
3492 | probe = TREE_OPERAND (probe, 0); | |
3493 | break; | |
3494 | ||
3495 | default: | |
3496 | object = probe; | |
9c96033c | 3497 | } |
3498 | } | |
3499 | ||
3500 | /* And then find/build up our initializer for the path to the subobject | |
3501 | we're initializing. */ | |
6fe83e54 | 3502 | tree *valp; |
43b7271d | 3503 | if (object == ctx->object && VAR_P (object) |
3504 | && DECL_NAME (object) && ctx->call == NULL) | |
3505 | /* The variable we're building up an aggregate initializer for is outside | |
3506 | the constant-expression, so don't evaluate the store. We check | |
3507 | DECL_NAME to handle TARGET_EXPR temporaries, which are fair game. */ | |
3508 | valp = NULL; | |
3509 | else if (DECL_P (object)) | |
6fe83e54 | 3510 | valp = ctx->values->get (object); |
3511 | else | |
3512 | valp = NULL; | |
9c96033c | 3513 | if (!valp) |
3514 | { | |
3515 | /* A constant-expression cannot modify objects from outside the | |
3516 | constant-expression. */ | |
f83e6885 | 3517 | if (!ctx->quiet) |
ea034e2c | 3518 | error ("modification of %qE is not a constant expression", object); |
9c96033c | 3519 | *non_constant_p = true; |
3520 | return t; | |
3521 | } | |
9db9fc38 | 3522 | type = TREE_TYPE (object); |
a02b42fe | 3523 | bool no_zero_init = true; |
58b0f9ce | 3524 | |
3525 | vec<tree,va_gc> *ctors = make_tree_vector (); | |
9c96033c | 3526 | while (!refs->is_empty()) |
3527 | { | |
3528 | if (*valp == NULL_TREE) | |
3529 | { | |
3530 | *valp = build_constructor (type, NULL); | |
a02b42fe | 3531 | CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp) = no_zero_init; |
9c96033c | 3532 | } |
92fe8840 | 3533 | else if (TREE_CODE (*valp) == STRING_CST) |
3534 | { | |
3535 | /* An array was initialized with a string constant, and now | |
3536 | we're writing into one of its elements. Explode the | |
3537 | single initialization into a set of element | |
3538 | initializations. */ | |
3539 | gcc_assert (TREE_CODE (type) == ARRAY_TYPE); | |
3540 | ||
3541 | tree string = *valp; | |
3542 | tree elt_type = TREE_TYPE (type); | |
3543 | unsigned chars_per_elt = (TYPE_PRECISION (elt_type) | |
3544 | / TYPE_PRECISION (char_type_node)); | |
3545 | unsigned num_elts = TREE_STRING_LENGTH (string) / chars_per_elt; | |
3546 | tree ary_ctor = build_constructor (type, NULL); | |
3547 | ||
3548 | vec_safe_reserve (CONSTRUCTOR_ELTS (ary_ctor), num_elts); | |
3549 | for (unsigned ix = 0; ix != num_elts; ix++) | |
3550 | { | |
3551 | constructor_elt elt = | |
3552 | { | |
3553 | build_int_cst (size_type_node, ix), | |
3554 | extract_string_elt (string, chars_per_elt, ix) | |
3555 | }; | |
3556 | CONSTRUCTOR_ELTS (ary_ctor)->quick_push (elt); | |
3557 | } | |
3558 | ||
3559 | *valp = ary_ctor; | |
3560 | } | |
3561 | ||
a02b42fe | 3562 | /* If the value of object is already zero-initialized, any new ctors for |
3563 | subobjects will also be zero-initialized. */ | |
3564 | no_zero_init = CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp); | |
9c96033c | 3565 | |
58b0f9ce | 3566 | vec_safe_push (ctors, *valp); |
3567 | ||
7963b19d | 3568 | enum tree_code code = TREE_CODE (type); |
9c96033c | 3569 | type = refs->pop(); |
7963b19d | 3570 | tree index = refs->pop(); |
9c96033c | 3571 | |
9c96033c | 3572 | constructor_elt *cep = NULL; |
7963b19d | 3573 | if (code == ARRAY_TYPE) |
3574 | { | |
3575 | HOST_WIDE_INT i | |
3576 | = find_array_ctor_elt (*valp, index, /*insert*/true); | |
3577 | gcc_assert (i >= 0); | |
3578 | cep = CONSTRUCTOR_ELT (*valp, i); | |
3579 | gcc_assert (TREE_CODE (cep->index) != RANGE_EXPR); | |
3580 | } | |
3581 | else | |
3582 | { | |
3583 | gcc_assert (TREE_CODE (index) == FIELD_DECL); | |
13ee2de7 | 3584 | |
3585 | /* We must keep the CONSTRUCTOR's ELTS in FIELD order. | |
3586 | Usually we meet initializers in that order, but it is | |
3587 | possible for base types to be placed not in program | |
3588 | order. */ | |
3589 | tree fields = TYPE_FIELDS (DECL_CONTEXT (index)); | |
3590 | unsigned HOST_WIDE_INT idx; | |
3591 | ||
ef782365 | 3592 | if (code == UNION_TYPE && CONSTRUCTOR_NELTS (*valp) |
3593 | && CONSTRUCTOR_ELT (*valp, 0)->index != index) | |
3594 | /* Changing active member. */ | |
3595 | vec_safe_truncate (CONSTRUCTOR_ELTS (*valp), 0); | |
3596 | ||
13ee2de7 | 3597 | for (idx = 0; |
7963b19d | 3598 | vec_safe_iterate (CONSTRUCTOR_ELTS (*valp), idx, &cep); |
13ee2de7 | 3599 | idx++, fields = DECL_CHAIN (fields)) |
7963b19d | 3600 | { |
13ee2de7 | 3601 | if (index == cep->index) |
3602 | goto found; | |
3603 | ||
3604 | /* The field we're initializing must be on the field | |
3605 | list. Look to see if it is present before the | |
3606 | field the current ELT initializes. */ | |
3607 | for (; fields != cep->index; fields = DECL_CHAIN (fields)) | |
3608 | if (index == fields) | |
3609 | goto insert; | |
7963b19d | 3610 | } |
13ee2de7 | 3611 | |
3612 | /* We fell off the end of the CONSTRUCTOR, so insert a new | |
3613 | entry at the end. */ | |
3614 | insert: | |
3615 | { | |
3616 | constructor_elt ce = { index, NULL_TREE }; | |
3617 | ||
3618 | vec_safe_insert (CONSTRUCTOR_ELTS (*valp), idx, ce); | |
3619 | cep = CONSTRUCTOR_ELT (*valp, idx); | |
3620 | } | |
3621 | found:; | |
7963b19d | 3622 | } |
9c96033c | 3623 | valp = &cep->value; |
3624 | } | |
3625 | release_tree_vector (refs); | |
3626 | ||
469dc5a6 | 3627 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) |
9c96033c | 3628 | { |
3629 | /* Create a new CONSTRUCTOR in case evaluation of the initializer | |
3630 | wants to modify it. */ | |
469dc5a6 | 3631 | if (*valp == NULL_TREE) |
6cded085 | 3632 | { |
6993e708 | 3633 | *valp = build_constructor (type, NULL); |
3634 | CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp) = no_zero_init; | |
6cded085 | 3635 | } |
6993e708 | 3636 | else if (TREE_CODE (*valp) == PTRMEM_CST) |
3637 | *valp = cplus_expand_constant (*valp); | |
3638 | new_ctx.ctor = *valp; | |
9c96033c | 3639 | new_ctx.object = target; |
3640 | } | |
3641 | ||
8a36d0ec | 3642 | init = cxx_eval_constant_expression (&new_ctx, init, false, |
3643 | non_constant_p, overflow_p); | |
7b9f713d | 3644 | /* Don't share a CONSTRUCTOR that might be changed later. */ |
e283bb4f | 3645 | init = unshare_constructor (init); |
9c96033c | 3646 | if (target == object) |
5579a199 | 3647 | /* The hash table might have moved since the get earlier. */ |
3648 | valp = ctx->values->get (object); | |
3649 | ||
3650 | if (TREE_CODE (init) == CONSTRUCTOR) | |
469dc5a6 | 3651 | { |
5579a199 | 3652 | /* An outer ctx->ctor might be pointing to *valp, so replace |
3653 | its contents. */ | |
3654 | CONSTRUCTOR_ELTS (*valp) = CONSTRUCTOR_ELTS (init); | |
3655 | TREE_CONSTANT (*valp) = TREE_CONSTANT (init); | |
3656 | TREE_SIDE_EFFECTS (*valp) = TREE_SIDE_EFFECTS (init); | |
b9786e35 | 3657 | CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp) |
3658 | = CONSTRUCTOR_NO_IMPLICIT_ZERO (init); | |
469dc5a6 | 3659 | } |
9c96033c | 3660 | else |
5579a199 | 3661 | *valp = init; |
58b0f9ce | 3662 | |
5579a199 | 3663 | /* Update TREE_CONSTANT and TREE_SIDE_EFFECTS on enclosing |
3664 | CONSTRUCTORs, if any. */ | |
3665 | tree elt; | |
3666 | unsigned i; | |
3667 | bool c = TREE_CONSTANT (init); | |
3668 | bool s = TREE_SIDE_EFFECTS (init); | |
3669 | if (!c || s) | |
3670 | FOR_EACH_VEC_SAFE_ELT (ctors, i, elt) | |
3671 | { | |
3672 | if (!c) | |
3673 | TREE_CONSTANT (elt) = false; | |
3674 | if (s) | |
3675 | TREE_SIDE_EFFECTS (elt) = true; | |
3676 | } | |
58b0f9ce | 3677 | release_tree_vector (ctors); |
9c96033c | 3678 | |
3679 | if (*non_constant_p) | |
3680 | return t; | |
1227ba74 | 3681 | else if (lval) |
9c96033c | 3682 | return target; |
3683 | else | |
dfac7dd2 | 3684 | return init; |
9c96033c | 3685 | } |
3686 | ||
3687 | /* Evaluate a ++ or -- expression. */ | |
3688 | ||
3689 | static tree | |
3690 | cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3691 | bool lval, |
9c96033c | 3692 | bool *non_constant_p, bool *overflow_p) |
3693 | { | |
3694 | enum tree_code code = TREE_CODE (t); | |
3695 | tree type = TREE_TYPE (t); | |
3696 | tree op = TREE_OPERAND (t, 0); | |
3697 | tree offset = TREE_OPERAND (t, 1); | |
3698 | gcc_assert (TREE_CONSTANT (offset)); | |
3699 | ||
3700 | /* The operand as an lvalue. */ | |
f83e6885 | 3701 | op = cxx_eval_constant_expression (ctx, op, true, |
b2a43197 | 3702 | non_constant_p, overflow_p); |
9c96033c | 3703 | |
3704 | /* The operand as an rvalue. */ | |
c017458d | 3705 | tree val |
3706 | = cxx_eval_constant_expression (ctx, op, false, | |
3707 | non_constant_p, overflow_p); | |
35f2c28f | 3708 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
3709 | a local array in a constexpr function. */ | |
3710 | bool ptr = POINTER_TYPE_P (TREE_TYPE (val)); | |
3711 | if (!ptr) | |
3712 | VERIFY_CONSTANT (val); | |
9c96033c | 3713 | |
3714 | /* The modified value. */ | |
3715 | bool inc = (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR); | |
c8a8f7ad | 3716 | tree mod; |
3717 | if (POINTER_TYPE_P (type)) | |
3718 | { | |
3719 | /* The middle end requires pointers to use POINTER_PLUS_EXPR. */ | |
3720 | offset = convert_to_ptrofftype (offset); | |
3721 | if (!inc) | |
3722 | offset = fold_build1 (NEGATE_EXPR, TREE_TYPE (offset), offset); | |
3723 | mod = fold_build2 (POINTER_PLUS_EXPR, type, val, offset); | |
3724 | } | |
3725 | else | |
3726 | mod = fold_build2 (inc ? PLUS_EXPR : MINUS_EXPR, type, val, offset); | |
35f2c28f | 3727 | if (!ptr) |
3728 | VERIFY_CONSTANT (mod); | |
9c96033c | 3729 | |
3730 | /* Storing the modified value. */ | |
3731 | tree store = build2 (MODIFY_EXPR, type, op, mod); | |
f83e6885 | 3732 | cxx_eval_constant_expression (ctx, store, |
b2a43197 | 3733 | true, non_constant_p, overflow_p); |
9c96033c | 3734 | |
3735 | /* And the value of the expression. */ | |
3736 | if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) | |
3737 | { | |
3738 | /* Prefix ops are lvalues. */ | |
1227ba74 | 3739 | if (lval) |
9c96033c | 3740 | return op; |
3741 | else | |
3742 | /* But we optimize when the caller wants an rvalue. */ | |
3743 | return mod; | |
3744 | } | |
3745 | else | |
3746 | /* Postfix ops are rvalues. */ | |
3747 | return val; | |
3748 | } | |
3749 | ||
00f21715 | 3750 | /* Predicates for the meaning of *jump_target. */ |
3751 | ||
3752 | static bool | |
3753 | returns (tree *jump_target) | |
3754 | { | |
3755 | return *jump_target | |
d29e4e8c | 3756 | && (TREE_CODE (*jump_target) == RETURN_EXPR |
3757 | || (TREE_CODE (*jump_target) == LABEL_DECL | |
3758 | && LABEL_DECL_CDTOR (*jump_target))); | |
00f21715 | 3759 | } |
3760 | ||
3761 | static bool | |
3762 | breaks (tree *jump_target) | |
3763 | { | |
3764 | return *jump_target | |
cf03ba19 | 3765 | && ((TREE_CODE (*jump_target) == LABEL_DECL |
3766 | && LABEL_DECL_BREAK (*jump_target)) | |
3767 | || TREE_CODE (*jump_target) == EXIT_EXPR); | |
00f21715 | 3768 | } |
3769 | ||
3770 | static bool | |
3771 | continues (tree *jump_target) | |
3772 | { | |
3773 | return *jump_target | |
3774 | && TREE_CODE (*jump_target) == LABEL_DECL | |
3775 | && LABEL_DECL_CONTINUE (*jump_target); | |
3776 | } | |
3777 | ||
3778 | static bool | |
3779 | switches (tree *jump_target) | |
3780 | { | |
3781 | return *jump_target | |
3782 | && TREE_CODE (*jump_target) == INTEGER_CST; | |
3783 | } | |
3784 | ||
3785 | /* Subroutine of cxx_eval_statement_list. Determine whether the statement | |
2a2770c6 | 3786 | STMT matches *jump_target. If we're looking for a case label and we see |
3787 | the default label, note it in ctx->css_state. */ | |
00f21715 | 3788 | |
3789 | static bool | |
2a2770c6 | 3790 | label_matches (const constexpr_ctx *ctx, tree *jump_target, tree stmt) |
00f21715 | 3791 | { |
00f21715 | 3792 | switch (TREE_CODE (*jump_target)) |
3793 | { | |
3794 | case LABEL_DECL: | |
3795 | if (TREE_CODE (stmt) == LABEL_EXPR | |
3796 | && LABEL_EXPR_LABEL (stmt) == *jump_target) | |
3797 | return true; | |
3798 | break; | |
3799 | ||
3800 | case INTEGER_CST: | |
3801 | if (TREE_CODE (stmt) == CASE_LABEL_EXPR) | |
3802 | { | |
2a2770c6 | 3803 | gcc_assert (ctx->css_state != NULL); |
00f21715 | 3804 | if (!CASE_LOW (stmt)) |
2a2770c6 | 3805 | { |
3806 | /* default: should appear just once in a SWITCH_EXPR | |
3807 | body (excluding nested SWITCH_EXPR). */ | |
3808 | gcc_assert (*ctx->css_state != css_default_seen); | |
3809 | /* When evaluating SWITCH_EXPR body for the second time, | |
3810 | return true for the default: label. */ | |
3811 | if (*ctx->css_state == css_default_processing) | |
3812 | return true; | |
3813 | *ctx->css_state = css_default_seen; | |
3814 | } | |
83c375ba | 3815 | else if (CASE_HIGH (stmt)) |
3816 | { | |
3817 | if (tree_int_cst_le (CASE_LOW (stmt), *jump_target) | |
3818 | && tree_int_cst_le (*jump_target, CASE_HIGH (stmt))) | |
3819 | return true; | |
3820 | } | |
00f21715 | 3821 | else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt))) |
3822 | return true; | |
3823 | } | |
3824 | break; | |
3825 | ||
3826 | default: | |
3827 | gcc_unreachable (); | |
3828 | } | |
3829 | return false; | |
3830 | } | |
3831 | ||
3832 | /* Evaluate a STATEMENT_LIST for side-effects. Handles various jump | |
3833 | semantics, for switch, break, continue, and return. */ | |
3834 | ||
3835 | static tree | |
3836 | cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3837 | bool *non_constant_p, bool *overflow_p, |
3838 | tree *jump_target) | |
3839 | { | |
3840 | tree_stmt_iterator i; | |
da7981e0 | 3841 | tree local_target; |
efea7c64 | 3842 | /* In a statement-expression we want to return the last value. |
3843 | For empty statement expression return void_node. */ | |
3844 | tree r = void_node; | |
da7981e0 | 3845 | if (!jump_target) |
3846 | { | |
3847 | local_target = NULL_TREE; | |
3848 | jump_target = &local_target; | |
3849 | } | |
00f21715 | 3850 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) |
3851 | { | |
00f21715 | 3852 | tree stmt = tsi_stmt (i); |
da7981e0 | 3853 | r = cxx_eval_constant_expression (ctx, stmt, false, |
3854 | non_constant_p, overflow_p, | |
3855 | jump_target); | |
00f21715 | 3856 | if (*non_constant_p) |
3857 | break; | |
3858 | if (returns (jump_target) || breaks (jump_target)) | |
3859 | break; | |
3860 | } | |
90567983 | 3861 | /* Make sure we don't use the "result" of a debug-only marker. That |
3862 | would be wrong. We should be using the result of the previous | |
3863 | statement, or NULL if there isn't one. In practice, this should | |
3864 | never happen: the statement after the marker should override the | |
3865 | result of the marker, so its value shouldn't survive in R. Now, | |
3866 | should that ever change, we'll need some fixing here to stop | |
3867 | markers from modifying the generated executable code. */ | |
3868 | gcc_checking_assert (!r || TREE_CODE (r) != DEBUG_BEGIN_STMT); | |
da7981e0 | 3869 | return r; |
00f21715 | 3870 | } |
3871 | ||
3872 | /* Evaluate a LOOP_EXPR for side-effects. Handles break and return | |
3873 | semantics; continue semantics are covered by cxx_eval_statement_list. */ | |
3874 | ||
3875 | static tree | |
3876 | cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3877 | bool *non_constant_p, bool *overflow_p, |
3878 | tree *jump_target) | |
3879 | { | |
2631cb67 | 3880 | constexpr_ctx new_ctx = *ctx; |
3881 | ||
00f21715 | 3882 | tree body = TREE_OPERAND (t, 0); |
21483ab7 | 3883 | int count = 0; |
5370eb8d | 3884 | do |
00f21715 | 3885 | { |
2631cb67 | 3886 | hash_set<tree> save_exprs; |
3887 | new_ctx.save_exprs = &save_exprs; | |
3888 | ||
cf03ba19 | 3889 | cxx_eval_constant_expression (&new_ctx, body, /*lval*/false, |
3890 | non_constant_p, overflow_p, jump_target); | |
2631cb67 | 3891 | |
3892 | /* Forget saved values of SAVE_EXPRs. */ | |
3893 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
3894 | iter != save_exprs.end(); ++iter) | |
3895 | new_ctx.values->remove (*iter); | |
21483ab7 | 3896 | if (++count >= constexpr_loop_limit) |
3897 | { | |
3898 | if (!ctx->quiet) | |
3899 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
5967b28b | 3900 | "%<constexpr%> loop iteration count exceeds limit of %d " |
21483ab7 | 3901 | "(use -fconstexpr-loop-limit= to increase the limit)", |
3902 | constexpr_loop_limit); | |
3903 | *non_constant_p = true; | |
3904 | break; | |
3905 | } | |
00f21715 | 3906 | } |
2a2770c6 | 3907 | while (!returns (jump_target) |
3908 | && !breaks (jump_target) | |
3909 | && !switches (jump_target) | |
3910 | && !*non_constant_p); | |
5370eb8d | 3911 | |
00f21715 | 3912 | if (breaks (jump_target)) |
3913 | *jump_target = NULL_TREE; | |
2631cb67 | 3914 | |
00f21715 | 3915 | return NULL_TREE; |
3916 | } | |
3917 | ||
3918 | /* Evaluate a SWITCH_EXPR for side-effects. Handles switch and break jump | |
3919 | semantics. */ | |
3920 | ||
3921 | static tree | |
3922 | cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3923 | bool *non_constant_p, bool *overflow_p, |
3924 | tree *jump_target) | |
3925 | { | |
3926 | tree cond = TREE_OPERAND (t, 0); | |
f83e6885 | 3927 | cond = cxx_eval_constant_expression (ctx, cond, false, |
b2a43197 | 3928 | non_constant_p, overflow_p); |
00f21715 | 3929 | VERIFY_CONSTANT (cond); |
3930 | *jump_target = cond; | |
3931 | ||
3932 | tree body = TREE_OPERAND (t, 1); | |
2a2770c6 | 3933 | constexpr_ctx new_ctx = *ctx; |
3934 | constexpr_switch_state css = css_default_not_seen; | |
3935 | new_ctx.css_state = &css; | |
3936 | cxx_eval_constant_expression (&new_ctx, body, false, | |
3937 | non_constant_p, overflow_p, jump_target); | |
3938 | if (switches (jump_target) && css == css_default_seen) | |
3939 | { | |
3940 | /* If the SWITCH_EXPR body has default: label, process it once again, | |
3941 | this time instructing label_matches to return true for default: | |
3942 | label on switches (jump_target). */ | |
3943 | css = css_default_processing; | |
3944 | cxx_eval_constant_expression (&new_ctx, body, false, | |
3945 | non_constant_p, overflow_p, jump_target); | |
3946 | } | |
00f21715 | 3947 | if (breaks (jump_target) || switches (jump_target)) |
3948 | *jump_target = NULL_TREE; | |
3949 | return NULL_TREE; | |
3950 | } | |
3951 | ||
85de9604 | 3952 | /* Find the object of TYPE under initialization in CTX. */ |
3953 | ||
3954 | static tree | |
3955 | lookup_placeholder (const constexpr_ctx *ctx, bool lval, tree type) | |
3956 | { | |
def8e41f | 3957 | if (!ctx) |
85de9604 | 3958 | return NULL_TREE; |
3959 | ||
3960 | /* We could use ctx->object unconditionally, but using ctx->ctor when we | |
3961 | can is a minor optimization. */ | |
def8e41f | 3962 | if (!lval && ctx->ctor && same_type_p (TREE_TYPE (ctx->ctor), type)) |
85de9604 | 3963 | return ctx->ctor; |
3964 | ||
def8e41f | 3965 | if (!ctx->object) |
3966 | return NULL_TREE; | |
3967 | ||
85de9604 | 3968 | /* Since an object cannot have a field of its own type, we can search outward |
3969 | from ctx->object to find the unique containing object of TYPE. */ | |
3970 | tree ob = ctx->object; | |
3971 | while (ob) | |
3972 | { | |
3973 | if (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (ob), type)) | |
3974 | break; | |
3975 | if (handled_component_p (ob)) | |
3976 | ob = TREE_OPERAND (ob, 0); | |
3977 | else | |
3978 | ob = NULL_TREE; | |
3979 | } | |
3980 | ||
3981 | return ob; | |
3982 | } | |
3983 | ||
09b42213 | 3984 | /* Attempt to reduce the expression T to a constant value. |
3985 | On failure, issue diagnostic and return error_mark_node. */ | |
3986 | /* FIXME unify with c_fully_fold */ | |
9c96033c | 3987 | /* FIXME overflow_p is too global */ |
09b42213 | 3988 | |
3989 | static tree | |
cf72f34d | 3990 | cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3991 | bool lval, |
00f21715 | 3992 | bool *non_constant_p, bool *overflow_p, |
3993 | tree *jump_target) | |
09b42213 | 3994 | { |
cf72f34d | 3995 | constexpr_ctx new_ctx; |
09b42213 | 3996 | tree r = t; |
3997 | ||
2a2770c6 | 3998 | if (jump_target && *jump_target) |
3999 | { | |
4000 | /* If we are jumping, ignore all statements/expressions except those | |
4001 | that could have LABEL_EXPR or CASE_LABEL_EXPR in their bodies. */ | |
4002 | switch (TREE_CODE (t)) | |
4003 | { | |
4004 | case BIND_EXPR: | |
4005 | case STATEMENT_LIST: | |
4006 | case LOOP_EXPR: | |
4007 | case COND_EXPR: | |
4008 | break; | |
4009 | case LABEL_EXPR: | |
4010 | case CASE_LABEL_EXPR: | |
4011 | if (label_matches (ctx, jump_target, t)) | |
4012 | /* Found it. */ | |
4013 | *jump_target = NULL_TREE; | |
4014 | return NULL_TREE; | |
4015 | default: | |
4016 | return NULL_TREE; | |
4017 | } | |
4018 | } | |
09b42213 | 4019 | if (t == error_mark_node) |
4020 | { | |
4021 | *non_constant_p = true; | |
4022 | return t; | |
4023 | } | |
4024 | if (CONSTANT_CLASS_P (t)) | |
4025 | { | |
c4fa85c9 | 4026 | if (TREE_OVERFLOW (t)) |
4027 | { | |
4028 | if (!ctx->quiet) | |
4029 | permerror (input_location, "overflow in constant expression"); | |
4030 | if (!flag_permissive || ctx->quiet) | |
4031 | *overflow_p = true; | |
4032 | } | |
cb768824 | 4033 | |
4034 | if (TREE_CODE (t) == INTEGER_CST | |
4035 | && TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE | |
4036 | && !integer_zerop (t)) | |
4037 | { | |
4038 | if (!ctx->quiet) | |
4039 | error ("value %qE of type %qT is not a constant expression", | |
4040 | t, TREE_TYPE (t)); | |
4041 | *non_constant_p = true; | |
4042 | } | |
4043 | ||
09b42213 | 4044 | return t; |
4045 | } | |
09b42213 | 4046 | |
cb768824 | 4047 | tree_code tcode = TREE_CODE (t); |
4048 | switch (tcode) | |
09b42213 | 4049 | { |
9c96033c | 4050 | case RESULT_DECL: |
1227ba74 | 4051 | if (lval) |
9c96033c | 4052 | return t; |
4053 | /* We ask for an rvalue for the RESULT_DECL when indirecting | |
92a9c89e | 4054 | through an invisible reference, or in named return value |
4055 | optimization. */ | |
9c96033c | 4056 | return (*ctx->values->get (t)); |
4057 | ||
09b42213 | 4058 | case VAR_DECL: |
9c8aeb66 | 4059 | if (DECL_HAS_VALUE_EXPR_P (t)) |
33603066 | 4060 | return cxx_eval_constant_expression (ctx, DECL_VALUE_EXPR (t), |
4061 | lval, non_constant_p, overflow_p); | |
e3533433 | 4062 | /* fall through */ |
8b2b2f24 | 4063 | case CONST_DECL: |
4064 | /* We used to not check lval for CONST_DECL, but darwin.c uses | |
4065 | CONST_DECL for aggregate constants. */ | |
1227ba74 | 4066 | if (lval) |
09b42213 | 4067 | return t; |
594cc00c | 4068 | if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
4069 | && is_really_empty_class (TREE_TYPE (t))) | |
c7282bf2 | 4070 | { |
4071 | /* If the class is empty, we aren't actually loading anything. */ | |
4072 | r = build_constructor (TREE_TYPE (t), NULL); | |
4073 | TREE_CONSTANT (r) = true; | |
4074 | } | |
4075 | else if (ctx->strict) | |
2055d27a | 4076 | r = decl_really_constant_value (t); |
4077 | else | |
4078 | r = decl_constant_value (t); | |
09b42213 | 4079 | if (TREE_CODE (r) == TARGET_EXPR |
4080 | && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR) | |
4081 | r = TARGET_EXPR_INITIAL (r); | |
f4ae4202 | 4082 | if (VAR_P (r)) |
cf72f34d | 4083 | if (tree *p = ctx->values->get (r)) |
a143e277 | 4084 | if (*p != NULL_TREE) |
4085 | r = *p; | |
09b42213 | 4086 | if (DECL_P (r)) |
4087 | { | |
f83e6885 | 4088 | if (!ctx->quiet) |
09b42213 | 4089 | non_const_var_error (r); |
4090 | *non_constant_p = true; | |
4091 | } | |
4092 | break; | |
4093 | ||
90567983 | 4094 | case DEBUG_BEGIN_STMT: |
4095 | /* ??? It might be nice to retain this information somehow, so | |
4096 | as to be able to step into a constexpr function call. */ | |
4097 | /* Fall through. */ | |
4098 | ||
09b42213 | 4099 | case FUNCTION_DECL: |
4100 | case TEMPLATE_DECL: | |
4101 | case LABEL_DECL: | |
00f21715 | 4102 | case LABEL_EXPR: |
4103 | case CASE_LABEL_EXPR: | |
2a2770c6 | 4104 | case PREDICT_EXPR: |
09b42213 | 4105 | return t; |
4106 | ||
4107 | case PARM_DECL: | |
88a59139 | 4108 | if (lval && TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE) |
9c96033c | 4109 | /* glvalue use. */; |
4110 | else if (tree *p = ctx->values->get (r)) | |
4111 | r = *p; | |
1227ba74 | 4112 | else if (lval) |
09b42213 | 4113 | /* Defer in case this is only used for its type. */; |
1eb418cc | 4114 | else if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE) |
4115 | /* Defer, there's no lvalue->rvalue conversion. */; | |
53d2f3de | 4116 | else if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
4117 | && is_really_empty_class (TREE_TYPE (t))) | |
a6613de7 | 4118 | { |
4119 | /* If the class is empty, we aren't actually loading anything. */ | |
4120 | r = build_constructor (TREE_TYPE (t), NULL); | |
4121 | TREE_CONSTANT (r) = true; | |
4122 | } | |
09b42213 | 4123 | else |
4124 | { | |
f83e6885 | 4125 | if (!ctx->quiet) |
09b42213 | 4126 | error ("%qE is not a constant expression", t); |
4127 | *non_constant_p = true; | |
4128 | } | |
4129 | break; | |
4130 | ||
4131 | case CALL_EXPR: | |
4132 | case AGGR_INIT_EXPR: | |
1227ba74 | 4133 | r = cxx_eval_call_expression (ctx, t, lval, |
09b42213 | 4134 | non_constant_p, overflow_p); |
4135 | break; | |
4136 | ||
9c96033c | 4137 | case DECL_EXPR: |
4138 | { | |
4139 | r = DECL_EXPR_DECL (t); | |
4140 | if (AGGREGATE_TYPE_P (TREE_TYPE (r)) | |
4141 | || VECTOR_TYPE_P (TREE_TYPE (r))) | |
4142 | { | |
4143 | new_ctx = *ctx; | |
4144 | new_ctx.object = r; | |
4145 | new_ctx.ctor = build_constructor (TREE_TYPE (r), NULL); | |
4146 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
4147 | new_ctx.values->put (r, new_ctx.ctor); | |
4148 | ctx = &new_ctx; | |
4149 | } | |
4150 | ||
4151 | if (tree init = DECL_INITIAL (r)) | |
4152 | { | |
4153 | init = cxx_eval_constant_expression (ctx, init, | |
f83e6885 | 4154 | false, |
b2a43197 | 4155 | non_constant_p, overflow_p); |
5898f0d7 | 4156 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 4157 | init = unshare_constructor (init); |
9c96033c | 4158 | ctx->values->put (r, init); |
4159 | } | |
4160 | else if (ctx == &new_ctx) | |
4161 | /* We gave it a CONSTRUCTOR above. */; | |
4162 | else | |
4163 | ctx->values->put (r, NULL_TREE); | |
4164 | } | |
4165 | break; | |
4166 | ||
09b42213 | 4167 | case TARGET_EXPR: |
4168 | if (!literal_type_p (TREE_TYPE (t))) | |
4169 | { | |
f83e6885 | 4170 | if (!ctx->quiet) |
09b42213 | 4171 | { |
4172 | error ("temporary of non-literal type %qT in a " | |
4173 | "constant expression", TREE_TYPE (t)); | |
4174 | explain_non_literal_class (TREE_TYPE (t)); | |
4175 | } | |
4176 | *non_constant_p = true; | |
4177 | break; | |
4178 | } | |
cf72f34d | 4179 | if ((AGGREGATE_TYPE_P (TREE_TYPE (t)) || VECTOR_TYPE_P (TREE_TYPE (t)))) |
4180 | { | |
4181 | /* We're being expanded without an explicit target, so start | |
4182 | initializing a new object; expansion with an explicit target | |
4183 | strips the TARGET_EXPR before we get here. */ | |
4184 | new_ctx = *ctx; | |
4185 | new_ctx.ctor = build_constructor (TREE_TYPE (t), NULL); | |
4186 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
4187 | new_ctx.object = TARGET_EXPR_SLOT (t); | |
4188 | ctx->values->put (new_ctx.object, new_ctx.ctor); | |
4189 | ctx = &new_ctx; | |
4190 | } | |
1227ba74 | 4191 | /* Pass false for 'lval' because this indicates |
09b42213 | 4192 | initialization of a temporary. */ |
cf72f34d | 4193 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 4194 | false, |
b2a43197 | 4195 | non_constant_p, overflow_p); |
09b42213 | 4196 | if (!*non_constant_p) |
4197 | /* Adjust the type of the result to the type of the temporary. */ | |
4198 | r = adjust_temp_type (TREE_TYPE (t), r); | |
1227ba74 | 4199 | if (lval) |
1eb418cc | 4200 | { |
4201 | tree slot = TARGET_EXPR_SLOT (t); | |
e283bb4f | 4202 | r = unshare_constructor (r); |
1eb418cc | 4203 | ctx->values->put (slot, r); |
4204 | return slot; | |
4205 | } | |
09b42213 | 4206 | break; |
4207 | ||
9c96033c | 4208 | case INIT_EXPR: |
9c96033c | 4209 | case MODIFY_EXPR: |
2a2770c6 | 4210 | gcc_assert (jump_target == NULL || *jump_target == NULL_TREE); |
1227ba74 | 4211 | r = cxx_eval_store_expression (ctx, t, lval, |
9c96033c | 4212 | non_constant_p, overflow_p); |
4213 | break; | |
4214 | ||
09b42213 | 4215 | case SCOPE_REF: |
cf72f34d | 4216 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 4217 | lval, |
b2a43197 | 4218 | non_constant_p, overflow_p); |
09b42213 | 4219 | break; |
4220 | ||
4221 | case RETURN_EXPR: | |
10fb495c | 4222 | if (TREE_OPERAND (t, 0) != NULL_TREE) |
4223 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
4224 | lval, | |
4225 | non_constant_p, overflow_p); | |
00f21715 | 4226 | *jump_target = t; |
4227 | break; | |
4228 | ||
e0e672a0 | 4229 | case SAVE_EXPR: |
4230 | /* Avoid evaluating a SAVE_EXPR more than once. */ | |
4231 | if (tree *p = ctx->values->get (t)) | |
4232 | r = *p; | |
4233 | else | |
4234 | { | |
c8f6aeb1 | 4235 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), false, |
e0e672a0 | 4236 | non_constant_p, overflow_p); |
4237 | ctx->values->put (t, r); | |
2631cb67 | 4238 | if (ctx->save_exprs) |
4239 | ctx->save_exprs->add (t); | |
e0e672a0 | 4240 | } |
4241 | break; | |
4242 | ||
09b42213 | 4243 | case NON_LVALUE_EXPR: |
4244 | case TRY_CATCH_EXPR: | |
7f67d68c | 4245 | case TRY_BLOCK: |
09b42213 | 4246 | case CLEANUP_POINT_EXPR: |
4247 | case MUST_NOT_THROW_EXPR: | |
9c96033c | 4248 | case EXPR_STMT: |
4249 | case EH_SPEC_BLOCK: | |
cf72f34d | 4250 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 4251 | lval, |
00f21715 | 4252 | non_constant_p, overflow_p, |
4253 | jump_target); | |
09b42213 | 4254 | break; |
4255 | ||
7f67d68c | 4256 | case TRY_FINALLY_EXPR: |
4257 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4258 | non_constant_p, overflow_p, | |
4259 | jump_target); | |
4260 | if (!*non_constant_p) | |
4261 | /* Also evaluate the cleanup. */ | |
4262 | cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), true, | |
4263 | non_constant_p, overflow_p, | |
4264 | jump_target); | |
4265 | break; | |
4266 | ||
09b42213 | 4267 | /* These differ from cxx_eval_unary_expression in that this doesn't |
4268 | check for a constant operand or result; an address can be | |
4269 | constant without its operand being, and vice versa. */ | |
d2c63826 | 4270 | case MEM_REF: |
09b42213 | 4271 | case INDIRECT_REF: |
1227ba74 | 4272 | r = cxx_eval_indirect_ref (ctx, t, lval, |
09b42213 | 4273 | non_constant_p, overflow_p); |
4274 | break; | |
4275 | ||
4276 | case ADDR_EXPR: | |
4277 | { | |
4278 | tree oldop = TREE_OPERAND (t, 0); | |
cf72f34d | 4279 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4280 | /*lval*/true, |
b2a43197 | 4281 | non_constant_p, overflow_p); |
09b42213 | 4282 | /* Don't VERIFY_CONSTANT here. */ |
4283 | if (*non_constant_p) | |
4284 | return t; | |
1eb418cc | 4285 | gcc_checking_assert (TREE_CODE (op) != CONSTRUCTOR); |
09b42213 | 4286 | /* This function does more aggressive folding than fold itself. */ |
4287 | r = build_fold_addr_expr_with_type (op, TREE_TYPE (t)); | |
4288 | if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop) | |
4289 | return t; | |
4290 | break; | |
4291 | } | |
4292 | ||
4293 | case REALPART_EXPR: | |
4294 | case IMAGPART_EXPR: | |
6fe424c2 | 4295 | if (lval) |
4296 | { | |
4297 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4298 | non_constant_p, overflow_p); | |
4299 | if (r == error_mark_node) | |
4300 | ; | |
4301 | else if (r == TREE_OPERAND (t, 0)) | |
4302 | r = t; | |
4303 | else | |
4304 | r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), r); | |
4305 | break; | |
4306 | } | |
4307 | /* FALLTHRU */ | |
09b42213 | 4308 | case CONJ_EXPR: |
4309 | case FIX_TRUNC_EXPR: | |
4310 | case FLOAT_EXPR: | |
4311 | case NEGATE_EXPR: | |
4312 | case ABS_EXPR: | |
4313 | case BIT_NOT_EXPR: | |
4314 | case TRUTH_NOT_EXPR: | |
4315 | case FIXED_CONVERT_EXPR: | |
1227ba74 | 4316 | r = cxx_eval_unary_expression (ctx, t, lval, |
09b42213 | 4317 | non_constant_p, overflow_p); |
4318 | break; | |
4319 | ||
4320 | case SIZEOF_EXPR: | |
d2c63826 | 4321 | r = fold_sizeof_expr (t); |
09b42213 | 4322 | VERIFY_CONSTANT (r); |
4323 | break; | |
4324 | ||
4325 | case COMPOUND_EXPR: | |
4326 | { | |
4327 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
4328 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
4329 | introduced by build_call_a. */ | |
4330 | tree op0 = TREE_OPERAND (t, 0); | |
4331 | tree op1 = TREE_OPERAND (t, 1); | |
4332 | STRIP_NOPS (op1); | |
4333 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
4334 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
f83e6885 | 4335 | r = cxx_eval_constant_expression (ctx, op0, |
1227ba74 | 4336 | lval, non_constant_p, overflow_p, |
00f21715 | 4337 | jump_target); |
09b42213 | 4338 | else |
4339 | { | |
4340 | /* Check that the LHS is constant and then discard it. */ | |
f83e6885 | 4341 | cxx_eval_constant_expression (ctx, op0, |
c8f6aeb1 | 4342 | true, non_constant_p, overflow_p, |
00f21715 | 4343 | jump_target); |
cf03ba19 | 4344 | if (*non_constant_p) |
4345 | return t; | |
09b42213 | 4346 | op1 = TREE_OPERAND (t, 1); |
f83e6885 | 4347 | r = cxx_eval_constant_expression (ctx, op1, |
1227ba74 | 4348 | lval, non_constant_p, overflow_p, |
00f21715 | 4349 | jump_target); |
09b42213 | 4350 | } |
4351 | } | |
4352 | break; | |
4353 | ||
4354 | case POINTER_PLUS_EXPR: | |
57e83b58 | 4355 | case POINTER_DIFF_EXPR: |
09b42213 | 4356 | case PLUS_EXPR: |
4357 | case MINUS_EXPR: | |
4358 | case MULT_EXPR: | |
4359 | case TRUNC_DIV_EXPR: | |
4360 | case CEIL_DIV_EXPR: | |
4361 | case FLOOR_DIV_EXPR: | |
4362 | case ROUND_DIV_EXPR: | |
4363 | case TRUNC_MOD_EXPR: | |
4364 | case CEIL_MOD_EXPR: | |
4365 | case ROUND_MOD_EXPR: | |
4366 | case RDIV_EXPR: | |
4367 | case EXACT_DIV_EXPR: | |
4368 | case MIN_EXPR: | |
4369 | case MAX_EXPR: | |
4370 | case LSHIFT_EXPR: | |
4371 | case RSHIFT_EXPR: | |
4372 | case LROTATE_EXPR: | |
4373 | case RROTATE_EXPR: | |
4374 | case BIT_IOR_EXPR: | |
4375 | case BIT_XOR_EXPR: | |
4376 | case BIT_AND_EXPR: | |
4377 | case TRUTH_XOR_EXPR: | |
4378 | case LT_EXPR: | |
4379 | case LE_EXPR: | |
4380 | case GT_EXPR: | |
4381 | case GE_EXPR: | |
4382 | case EQ_EXPR: | |
4383 | case NE_EXPR: | |
4384 | case UNORDERED_EXPR: | |
4385 | case ORDERED_EXPR: | |
4386 | case UNLT_EXPR: | |
4387 | case UNLE_EXPR: | |
4388 | case UNGT_EXPR: | |
4389 | case UNGE_EXPR: | |
4390 | case UNEQ_EXPR: | |
4391 | case LTGT_EXPR: | |
4392 | case RANGE_EXPR: | |
4393 | case COMPLEX_EXPR: | |
1227ba74 | 4394 | r = cxx_eval_binary_expression (ctx, t, lval, |
09b42213 | 4395 | non_constant_p, overflow_p); |
4396 | break; | |
4397 | ||
4398 | /* fold can introduce non-IF versions of these; still treat them as | |
4399 | short-circuiting. */ | |
4400 | case TRUTH_AND_EXPR: | |
4401 | case TRUTH_ANDIF_EXPR: | |
cf72f34d | 4402 | r = cxx_eval_logical_expression (ctx, t, boolean_false_node, |
09b42213 | 4403 | boolean_true_node, |
1227ba74 | 4404 | lval, |
09b42213 | 4405 | non_constant_p, overflow_p); |
4406 | break; | |
4407 | ||
4408 | case TRUTH_OR_EXPR: | |
4409 | case TRUTH_ORIF_EXPR: | |
cf72f34d | 4410 | r = cxx_eval_logical_expression (ctx, t, boolean_true_node, |
09b42213 | 4411 | boolean_false_node, |
1227ba74 | 4412 | lval, |
09b42213 | 4413 | non_constant_p, overflow_p); |
4414 | break; | |
4415 | ||
4416 | case ARRAY_REF: | |
1227ba74 | 4417 | r = cxx_eval_array_reference (ctx, t, lval, |
09b42213 | 4418 | non_constant_p, overflow_p); |
4419 | break; | |
4420 | ||
4421 | case COMPONENT_REF: | |
4422 | if (is_overloaded_fn (t)) | |
4423 | { | |
4424 | /* We can only get here in checking mode via | |
4425 | build_non_dependent_expr, because any expression that | |
4426 | calls or takes the address of the function will have | |
4427 | pulled a FUNCTION_DECL out of the COMPONENT_REF. */ | |
f83e6885 | 4428 | gcc_checking_assert (ctx->quiet || errorcount); |
09b42213 | 4429 | *non_constant_p = true; |
4430 | return t; | |
4431 | } | |
1227ba74 | 4432 | r = cxx_eval_component_reference (ctx, t, lval, |
09b42213 | 4433 | non_constant_p, overflow_p); |
4434 | break; | |
4435 | ||
4436 | case BIT_FIELD_REF: | |
1227ba74 | 4437 | r = cxx_eval_bit_field_ref (ctx, t, lval, |
09b42213 | 4438 | non_constant_p, overflow_p); |
4439 | break; | |
4440 | ||
4441 | case COND_EXPR: | |
2a2770c6 | 4442 | if (jump_target && *jump_target) |
4443 | { | |
4444 | /* When jumping to a label, the label might be either in the | |
4445 | then or else blocks, so process then block first in skipping | |
4446 | mode first, and if we are still in the skipping mode at its end, | |
4447 | process the else block too. */ | |
4448 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
4449 | lval, non_constant_p, overflow_p, | |
4450 | jump_target); | |
4451 | if (*jump_target) | |
4452 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
4453 | lval, non_constant_p, overflow_p, | |
4454 | jump_target); | |
4455 | break; | |
4456 | } | |
1227ba74 | 4457 | r = cxx_eval_conditional_expression (ctx, t, lval, |
00f21715 | 4458 | non_constant_p, overflow_p, |
4459 | jump_target); | |
09b42213 | 4460 | break; |
31595caf | 4461 | case VEC_COND_EXPR: |
4462 | r = cxx_eval_vector_conditional_expression (ctx, t, non_constant_p, | |
4463 | overflow_p); | |
4464 | break; | |
09b42213 | 4465 | |
4466 | case CONSTRUCTOR: | |
1a3631bc | 4467 | if (TREE_CONSTANT (t)) |
58b0f9ce | 4468 | { |
4469 | /* Don't re-process a constant CONSTRUCTOR, but do fold it to | |
4470 | VECTOR_CST if applicable. */ | |
4471 | /* FIXME after GCC 6 branches, make the verify unconditional. */ | |
4472 | if (CHECKING_P) | |
4473 | verify_constructor_flags (t); | |
4474 | else | |
4475 | recompute_constructor_flags (t); | |
4476 | if (TREE_CONSTANT (t)) | |
4477 | return fold (t); | |
4478 | } | |
1227ba74 | 4479 | r = cxx_eval_bare_aggregate (ctx, t, lval, |
09b42213 | 4480 | non_constant_p, overflow_p); |
4481 | break; | |
4482 | ||
4483 | case VEC_INIT_EXPR: | |
4484 | /* We can get this in a defaulted constructor for a class with a | |
4485 | non-static data member of array type. Either the initializer will | |
4486 | be NULL, meaning default-initialization, or it will be an lvalue | |
4487 | or xvalue of the same type, meaning direct-initialization from the | |
4488 | corresponding member. */ | |
1227ba74 | 4489 | r = cxx_eval_vec_init (ctx, t, lval, |
09b42213 | 4490 | non_constant_p, overflow_p); |
4491 | break; | |
4492 | ||
4493 | case FMA_EXPR: | |
4494 | case VEC_PERM_EXPR: | |
1227ba74 | 4495 | r = cxx_eval_trinary_expression (ctx, t, lval, |
09b42213 | 4496 | non_constant_p, overflow_p); |
4497 | break; | |
4498 | ||
4499 | case CONVERT_EXPR: | |
4500 | case VIEW_CONVERT_EXPR: | |
4501 | case NOP_EXPR: | |
d2c63826 | 4502 | case UNARY_PLUS_EXPR: |
09b42213 | 4503 | { |
4504 | tree oldop = TREE_OPERAND (t, 0); | |
d2c63826 | 4505 | |
cf72f34d | 4506 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4507 | lval, |
b2a43197 | 4508 | non_constant_p, overflow_p); |
09b42213 | 4509 | if (*non_constant_p) |
4510 | return t; | |
f16ed232 | 4511 | tree type = TREE_TYPE (t); |
4512 | if (TREE_CODE (op) == PTRMEM_CST | |
4513 | && !TYPE_PTRMEM_P (type)) | |
4514 | op = cplus_expand_constant (op); | |
6a9b35ef | 4515 | if (TREE_CODE (op) == PTRMEM_CST && tcode == NOP_EXPR) |
4516 | { | |
4517 | if (same_type_ignoring_top_level_qualifiers_p (type, | |
0a8a2108 | 4518 | TREE_TYPE (op)) |
4519 | || can_convert_qual (type, op)) | |
19d56e62 | 4520 | return cp_fold_convert (type, op); |
6a9b35ef | 4521 | else |
4522 | { | |
4523 | if (!ctx->quiet) | |
4524 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
ea034e2c | 4525 | "a reinterpret_cast is not a constant expression"); |
6a9b35ef | 4526 | *non_constant_p = true; |
4527 | return t; | |
4528 | } | |
4529 | } | |
cb768824 | 4530 | |
4531 | if (POINTER_TYPE_P (type) && TREE_CODE (op) == INTEGER_CST) | |
09b42213 | 4532 | { |
cb768824 | 4533 | if (integer_zerop (op)) |
4534 | { | |
4535 | if (TREE_CODE (type) == REFERENCE_TYPE) | |
4536 | { | |
4537 | if (!ctx->quiet) | |
4538 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4539 | "dereferencing a null pointer"); | |
4540 | *non_constant_p = true; | |
4541 | return t; | |
4542 | } | |
4543 | else if (TREE_CODE (TREE_TYPE (op)) == POINTER_TYPE) | |
4544 | { | |
4545 | tree from = TREE_TYPE (op); | |
4546 | ||
4547 | if (!can_convert (type, from, tf_none)) | |
4548 | { | |
4549 | if (!ctx->quiet) | |
4550 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4551 | "conversion of %qT null pointer to %qT " | |
4552 | "is not a constant expression", | |
4553 | from, type); | |
4554 | *non_constant_p = true; | |
4555 | return t; | |
4556 | } | |
4557 | } | |
4558 | } | |
4559 | else | |
4560 | { | |
4561 | /* This detects for example: | |
4562 | reinterpret_cast<void*>(sizeof 0) | |
4563 | */ | |
4564 | if (!ctx->quiet) | |
4565 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4566 | "%<reinterpret_cast<%T>(%E)%> is not " | |
ea034e2c | 4567 | "a constant expression", |
cb768824 | 4568 | type, op); |
4569 | *non_constant_p = true; | |
4570 | return t; | |
4571 | } | |
09b42213 | 4572 | } |
d2c63826 | 4573 | if (op == oldop && tcode != UNARY_PLUS_EXPR) |
09b42213 | 4574 | /* We didn't fold at the top so we could check for ptr-int |
4575 | conversion. */ | |
4576 | return fold (t); | |
d2c63826 | 4577 | if (tcode == UNARY_PLUS_EXPR) |
4578 | r = fold_convert (TREE_TYPE (t), op); | |
4579 | else | |
4580 | r = fold_build1 (tcode, type, op); | |
09b42213 | 4581 | /* Conversion of an out-of-range value has implementation-defined |
4582 | behavior; the language considers it different from arithmetic | |
4583 | overflow, which is undefined. */ | |
4584 | if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op)) | |
4585 | TREE_OVERFLOW (r) = false; | |
4586 | } | |
4587 | break; | |
4588 | ||
4589 | case EMPTY_CLASS_EXPR: | |
4590 | /* This is good enough for a function argument that might not get | |
4591 | used, and they can't do anything with it, so just return it. */ | |
4592 | return t; | |
4593 | ||
9c96033c | 4594 | case STATEMENT_LIST: |
00f21715 | 4595 | new_ctx = *ctx; |
4596 | new_ctx.ctor = new_ctx.object = NULL_TREE; | |
f83e6885 | 4597 | return cxx_eval_statement_list (&new_ctx, t, |
00f21715 | 4598 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4599 | |
4600 | case BIND_EXPR: | |
4601 | return cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t), | |
1227ba74 | 4602 | lval, |
00f21715 | 4603 | non_constant_p, overflow_p, |
4604 | jump_target); | |
9c96033c | 4605 | |
09b42213 | 4606 | case PREINCREMENT_EXPR: |
4607 | case POSTINCREMENT_EXPR: | |
4608 | case PREDECREMENT_EXPR: | |
4609 | case POSTDECREMENT_EXPR: | |
f83e6885 | 4610 | return cxx_eval_increment_expression (ctx, t, |
1227ba74 | 4611 | lval, non_constant_p, overflow_p); |
9c96033c | 4612 | |
4613 | case LAMBDA_EXPR: | |
09b42213 | 4614 | case NEW_EXPR: |
4615 | case VEC_NEW_EXPR: | |
4616 | case DELETE_EXPR: | |
4617 | case VEC_DELETE_EXPR: | |
4618 | case THROW_EXPR: | |
09b42213 | 4619 | case MODOP_EXPR: |
4620 | /* GCC internal stuff. */ | |
4621 | case VA_ARG_EXPR: | |
4622 | case OBJ_TYPE_REF: | |
09b42213 | 4623 | case NON_DEPENDENT_EXPR: |
4624 | case BASELINK: | |
09b42213 | 4625 | case OFFSET_REF: |
f83e6885 | 4626 | if (!ctx->quiet) |
09b42213 | 4627 | error_at (EXPR_LOC_OR_LOC (t, input_location), |
ea034e2c | 4628 | "expression %qE is not a constant expression", t); |
09b42213 | 4629 | *non_constant_p = true; |
4630 | break; | |
4631 | ||
cf72f34d | 4632 | case PLACEHOLDER_EXPR: |
85de9604 | 4633 | /* Use of the value or address of the current object. */ |
4634 | if (tree ctor = lookup_placeholder (ctx, lval, TREE_TYPE (t))) | |
4635 | return cxx_eval_constant_expression (ctx, ctor, lval, | |
4636 | non_constant_p, overflow_p); | |
4637 | /* A placeholder without a referent. We can get here when | |
4638 | checking whether NSDMIs are noexcept, or in massage_init_elt; | |
4639 | just say it's non-constant for now. */ | |
4640 | gcc_assert (ctx->quiet); | |
4641 | *non_constant_p = true; | |
cf72f34d | 4642 | break; |
4643 | ||
cf03ba19 | 4644 | case EXIT_EXPR: |
4645 | { | |
4646 | tree cond = TREE_OPERAND (t, 0); | |
4647 | cond = cxx_eval_constant_expression (ctx, cond, /*lval*/false, | |
4648 | non_constant_p, overflow_p); | |
4649 | VERIFY_CONSTANT (cond); | |
4650 | if (integer_nonzerop (cond)) | |
4651 | *jump_target = t; | |
4652 | } | |
4653 | break; | |
4654 | ||
9c96033c | 4655 | case GOTO_EXPR: |
00f21715 | 4656 | *jump_target = TREE_OPERAND (t, 0); |
d29e4e8c | 4657 | gcc_assert (breaks (jump_target) || continues (jump_target) |
4658 | /* Allow for jumping to a cdtor_label. */ | |
4659 | || returns (jump_target)); | |
00f21715 | 4660 | break; |
4661 | ||
9c96033c | 4662 | case LOOP_EXPR: |
f83e6885 | 4663 | cxx_eval_loop_expr (ctx, t, |
00f21715 | 4664 | non_constant_p, overflow_p, jump_target); |
4665 | break; | |
4666 | ||
9c96033c | 4667 | case SWITCH_EXPR: |
f83e6885 | 4668 | cxx_eval_switch_expr (ctx, t, |
00f21715 | 4669 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4670 | break; |
4671 | ||
56c12fd4 | 4672 | case REQUIRES_EXPR: |
4673 | /* It's possible to get a requires-expression in a constant | |
4674 | expression. For example: | |
4675 | ||
4676 | template<typename T> concept bool C() { | |
4677 | return requires (T t) { t; }; | |
4678 | } | |
4679 | ||
4680 | template<typename T> requires !C<T>() void f(T); | |
4681 | ||
4682 | Normalization leaves f with the associated constraint | |
4683 | '!requires (T t) { ... }' which is not transformed into | |
4684 | a constraint. */ | |
4685 | if (!processing_template_decl) | |
4686 | return evaluate_constraint_expression (t, NULL_TREE); | |
4687 | else | |
4688 | *non_constant_p = true; | |
4689 | return t; | |
4690 | ||
24c6ee98 | 4691 | case ANNOTATE_EXPR: |
4692 | gcc_assert (tree_to_uhwi (TREE_OPERAND (t, 1)) == annot_expr_ivdep_kind); | |
4693 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
4694 | lval, | |
4695 | non_constant_p, overflow_p, | |
4696 | jump_target); | |
4697 | break; | |
4698 | ||
09b42213 | 4699 | default: |
b9a3af23 | 4700 | if (STATEMENT_CODE_P (TREE_CODE (t))) |
4701 | { | |
4702 | /* This function doesn't know how to deal with pre-genericize | |
4703 | statements; this can only happen with statement-expressions, | |
4704 | so for now just fail. */ | |
4705 | if (!ctx->quiet) | |
4706 | error_at (EXPR_LOCATION (t), | |
ea034e2c | 4707 | "statement is not a constant expression"); |
b9a3af23 | 4708 | } |
4709 | else | |
4710 | internal_error ("unexpected expression %qE of kind %s", t, | |
4711 | get_tree_code_name (TREE_CODE (t))); | |
09b42213 | 4712 | *non_constant_p = true; |
4713 | break; | |
4714 | } | |
4715 | ||
4716 | if (r == error_mark_node) | |
4717 | *non_constant_p = true; | |
4718 | ||
4719 | if (*non_constant_p) | |
4720 | return t; | |
4721 | else | |
4722 | return r; | |
4723 | } | |
4724 | ||
4725 | static tree | |
cf72f34d | 4726 | cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, |
2055d27a | 4727 | bool strict = true, tree object = NULL_TREE) |
09b42213 | 4728 | { |
c300fe28 | 4729 | auto_timevar time (TV_CONSTEXPR); |
4730 | ||
09b42213 | 4731 | bool non_constant_p = false; |
4732 | bool overflow_p = false; | |
cf72f34d | 4733 | hash_map<tree,tree> map; |
2631cb67 | 4734 | |
2a2770c6 | 4735 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, NULL, NULL, |
2631cb67 | 4736 | allow_non_constant, strict }; |
4737 | ||
cf72f34d | 4738 | tree type = initialized_type (t); |
cf72f34d | 4739 | tree r = t; |
4740 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) | |
4741 | { | |
4742 | /* In C++14 an NSDMI can participate in aggregate initialization, | |
4743 | and can refer to the address of the object being initialized, so | |
4744 | we need to pass in the relevant VAR_DECL if we want to do the | |
4745 | evaluation in a single pass. The evaluation will dynamically | |
4746 | update ctx.values for the VAR_DECL. We use the same strategy | |
4747 | for C++11 constexpr constructors that refer to the object being | |
4748 | initialized. */ | |
4749 | ctx.ctor = build_constructor (type, NULL); | |
4750 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctx.ctor) = true; | |
9c96033c | 4751 | if (!object) |
4752 | { | |
4753 | if (TREE_CODE (t) == TARGET_EXPR) | |
4754 | object = TARGET_EXPR_SLOT (t); | |
4755 | else if (TREE_CODE (t) == AGGR_INIT_EXPR) | |
4756 | object = AGGR_INIT_EXPR_SLOT (t); | |
4757 | } | |
cf72f34d | 4758 | ctx.object = object; |
4759 | if (object) | |
4760 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
4761 | (type, TREE_TYPE (object))); | |
4762 | if (object && DECL_P (object)) | |
4763 | map.put (object, ctx.ctor); | |
4764 | if (TREE_CODE (r) == TARGET_EXPR) | |
4765 | /* Avoid creating another CONSTRUCTOR when we expand the | |
4766 | TARGET_EXPR. */ | |
4767 | r = TARGET_EXPR_INITIAL (r); | |
4768 | } | |
4769 | ||
f83e6885 | 4770 | r = cxx_eval_constant_expression (&ctx, r, |
b2a43197 | 4771 | false, &non_constant_p, &overflow_p); |
09b42213 | 4772 | |
4773 | verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); | |
4774 | ||
bbcc9042 | 4775 | /* Mutable logic is a bit tricky: we want to allow initialization of |
4776 | constexpr variables with mutable members, but we can't copy those | |
4777 | members to another constexpr variable. */ | |
4778 | if (TREE_CODE (r) == CONSTRUCTOR | |
4779 | && CONSTRUCTOR_MUTABLE_POISON (r)) | |
09b42213 | 4780 | { |
09b42213 | 4781 | if (!allow_non_constant) |
bbcc9042 | 4782 | error ("%qE is not a constant expression because it refers to " |
4783 | "mutable subobjects of %qT", t, type); | |
09b42213 | 4784 | non_constant_p = true; |
4785 | } | |
4786 | ||
c6d97004 | 4787 | if (TREE_CODE (r) == CONSTRUCTOR |
4788 | && CONSTRUCTOR_NO_IMPLICIT_ZERO (r)) | |
4789 | { | |
4790 | if (!allow_non_constant) | |
4791 | error ("%qE is not a constant expression because it refers to " | |
4792 | "an incompletely initialized variable", t); | |
4793 | TREE_CONSTANT (r) = false; | |
4794 | non_constant_p = true; | |
4795 | } | |
4796 | ||
09b42213 | 4797 | /* Technically we should check this for all subexpressions, but that |
4798 | runs into problems with our internal representation of pointer | |
4799 | subtraction and the 5.19 rules are still in flux. */ | |
4800 | if (CONVERT_EXPR_CODE_P (TREE_CODE (r)) | |
4801 | && ARITHMETIC_TYPE_P (TREE_TYPE (r)) | |
4802 | && TREE_CODE (TREE_OPERAND (r, 0)) == ADDR_EXPR) | |
4803 | { | |
4804 | if (!allow_non_constant) | |
4805 | error ("conversion from pointer type %qT " | |
ea034e2c | 4806 | "to arithmetic type %qT in a constant expression", |
09b42213 | 4807 | TREE_TYPE (TREE_OPERAND (r, 0)), TREE_TYPE (r)); |
4808 | non_constant_p = true; | |
4809 | } | |
4810 | ||
4811 | if (!non_constant_p && overflow_p) | |
4812 | non_constant_p = true; | |
4813 | ||
c6c0523b | 4814 | /* Unshare the result unless it's a CONSTRUCTOR in which case it's already |
4815 | unshared. */ | |
4816 | bool should_unshare = true; | |
4817 | if (r == t || TREE_CODE (r) == CONSTRUCTOR) | |
4818 | should_unshare = false; | |
4819 | ||
09b42213 | 4820 | if (non_constant_p && !allow_non_constant) |
4821 | return error_mark_node; | |
4822 | else if (non_constant_p && TREE_CONSTANT (r)) | |
4823 | { | |
4824 | /* This isn't actually constant, so unset TREE_CONSTANT. */ | |
4825 | if (EXPR_P (r)) | |
4826 | r = copy_node (r); | |
4827 | else if (TREE_CODE (r) == CONSTRUCTOR) | |
4828 | r = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (r), r); | |
4829 | else | |
4830 | r = build_nop (TREE_TYPE (r), r); | |
4831 | TREE_CONSTANT (r) = false; | |
4832 | } | |
4833 | else if (non_constant_p || r == t) | |
4834 | return t; | |
4835 | ||
c6c0523b | 4836 | if (should_unshare) |
4837 | r = unshare_expr (r); | |
4838 | ||
09b42213 | 4839 | if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r))) |
4840 | { | |
4841 | if (TREE_CODE (t) == TARGET_EXPR | |
4842 | && TARGET_EXPR_INITIAL (t) == r) | |
4843 | return t; | |
4844 | else | |
4845 | { | |
4846 | r = get_target_expr (r); | |
4847 | TREE_CONSTANT (r) = true; | |
4848 | return r; | |
4849 | } | |
4850 | } | |
4851 | else | |
4852 | return r; | |
4853 | } | |
4854 | ||
4855 | /* Returns true if T is a valid subexpression of a constant expression, | |
4856 | even if it isn't itself a constant expression. */ | |
4857 | ||
4858 | bool | |
4859 | is_sub_constant_expr (tree t) | |
4860 | { | |
4861 | bool non_constant_p = false; | |
4862 | bool overflow_p = false; | |
cf72f34d | 4863 | hash_map <tree, tree> map; |
2631cb67 | 4864 | |
2a2770c6 | 4865 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, NULL, NULL, true, true }; |
2631cb67 | 4866 | |
f83e6885 | 4867 | cxx_eval_constant_expression (&ctx, t, false, &non_constant_p, |
b2a43197 | 4868 | &overflow_p); |
09b42213 | 4869 | return !non_constant_p && !overflow_p; |
4870 | } | |
4871 | ||
4872 | /* If T represents a constant expression returns its reduced value. | |
4873 | Otherwise return error_mark_node. If T is dependent, then | |
4874 | return NULL. */ | |
4875 | ||
4876 | tree | |
cf72f34d | 4877 | cxx_constant_value (tree t, tree decl) |
09b42213 | 4878 | { |
2055d27a | 4879 | return cxx_eval_outermost_constant_expr (t, false, true, decl); |
09b42213 | 4880 | } |
4881 | ||
d2c63826 | 4882 | /* Helper routine for fold_simple function. Either return simplified |
4883 | expression T, otherwise NULL_TREE. | |
4884 | In contrast to cp_fully_fold, and to maybe_constant_value, we try to fold | |
4885 | even if we are within template-declaration. So be careful on call, as in | |
4886 | such case types can be undefined. */ | |
4887 | ||
4888 | static tree | |
4889 | fold_simple_1 (tree t) | |
4890 | { | |
4891 | tree op1; | |
4892 | enum tree_code code = TREE_CODE (t); | |
4893 | ||
4894 | switch (code) | |
4895 | { | |
4896 | case INTEGER_CST: | |
4897 | case REAL_CST: | |
4898 | case VECTOR_CST: | |
4899 | case FIXED_CST: | |
4900 | case COMPLEX_CST: | |
4901 | return t; | |
4902 | ||
4903 | case SIZEOF_EXPR: | |
4904 | return fold_sizeof_expr (t); | |
4905 | ||
4906 | case ABS_EXPR: | |
4907 | case CONJ_EXPR: | |
4908 | case REALPART_EXPR: | |
4909 | case IMAGPART_EXPR: | |
4910 | case NEGATE_EXPR: | |
4911 | case BIT_NOT_EXPR: | |
4912 | case TRUTH_NOT_EXPR: | |
4913 | case NOP_EXPR: | |
4914 | case VIEW_CONVERT_EXPR: | |
4915 | case CONVERT_EXPR: | |
4916 | case FLOAT_EXPR: | |
4917 | case FIX_TRUNC_EXPR: | |
4918 | case FIXED_CONVERT_EXPR: | |
4919 | case ADDR_SPACE_CONVERT_EXPR: | |
4920 | ||
4921 | op1 = TREE_OPERAND (t, 0); | |
4922 | ||
4923 | t = const_unop (code, TREE_TYPE (t), op1); | |
4924 | if (!t) | |
4925 | return NULL_TREE; | |
4926 | ||
4927 | if (CONVERT_EXPR_CODE_P (code) | |
4928 | && TREE_OVERFLOW_P (t) && !TREE_OVERFLOW_P (op1)) | |
4929 | TREE_OVERFLOW (t) = false; | |
4930 | return t; | |
4931 | ||
4932 | default: | |
4933 | return NULL_TREE; | |
4934 | } | |
4935 | } | |
4936 | ||
4937 | /* If T is a simple constant expression, returns its simplified value. | |
4938 | Otherwise returns T. In contrast to maybe_constant_value do we | |
4939 | simplify only few operations on constant-expressions, and we don't | |
4940 | try to simplify constexpressions. */ | |
4941 | ||
4942 | tree | |
4943 | fold_simple (tree t) | |
4944 | { | |
4945 | tree r = NULL_TREE; | |
4946 | if (processing_template_decl) | |
4947 | return t; | |
4948 | ||
4949 | r = fold_simple_1 (t); | |
4950 | if (!r) | |
4951 | r = t; | |
4952 | ||
4953 | return r; | |
4954 | } | |
4955 | ||
09b42213 | 4956 | /* If T is a constant expression, returns its reduced value. |
4957 | Otherwise, if T does not have TREE_CONSTANT set, returns T. | |
4958 | Otherwise, returns a version of T without TREE_CONSTANT. */ | |
4959 | ||
b601ad30 | 4960 | static GTY((deletable)) hash_map<tree, tree> *cv_cache; |
4961 | ||
4962 | tree | |
4963 | maybe_constant_value (tree t, tree decl) | |
09b42213 | 4964 | { |
4965 | tree r; | |
4966 | ||
7e1f8be4 | 4967 | if (!is_nondependent_constant_expression (t)) |
09b42213 | 4968 | { |
4969 | if (TREE_OVERFLOW_P (t)) | |
4970 | { | |
4971 | t = build_nop (TREE_TYPE (t), t); | |
4972 | TREE_CONSTANT (t) = false; | |
4973 | } | |
4974 | return t; | |
4975 | } | |
b601ad30 | 4976 | else if (CONSTANT_CLASS_P (t)) |
4977 | /* No caching or evaluation needed. */ | |
4978 | return t; | |
4979 | ||
4980 | if (cv_cache == NULL) | |
4981 | cv_cache = hash_map<tree, tree>::create_ggc (101); | |
4982 | if (tree *cached = cv_cache->get (t)) | |
4983 | return *cached; | |
09b42213 | 4984 | |
2055d27a | 4985 | r = cxx_eval_outermost_constant_expr (t, true, true, decl); |
5e8689fb | 4986 | gcc_checking_assert (r == t |
4987 | || CONVERT_EXPR_P (t) | |
4988 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
4989 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
4990 | || !cp_tree_equal (r, t)); | |
b601ad30 | 4991 | cv_cache->put (t, r); |
09b42213 | 4992 | return r; |
4993 | } | |
4994 | ||
2a655a4c | 4995 | /* Dispose of the whole CV_CACHE. */ |
4996 | ||
4997 | static void | |
4998 | clear_cv_cache (void) | |
4999 | { | |
5000 | if (cv_cache != NULL) | |
5001 | cv_cache->empty (); | |
5002 | } | |
5003 | ||
f553d9f8 | 5004 | /* Dispose of the whole CV_CACHE and FOLD_CACHE. */ |
a0c919f7 | 5005 | |
5006 | void | |
f553d9f8 | 5007 | clear_cv_and_fold_caches (void) |
a0c919f7 | 5008 | { |
2a655a4c | 5009 | clear_cv_cache (); |
f553d9f8 | 5010 | clear_fold_cache (); |
a0c919f7 | 5011 | } |
5012 | ||
21131a05 | 5013 | /* Like maybe_constant_value but first fully instantiate the argument. |
5014 | ||
5015 | Note: this is equivalent to instantiate_non_dependent_expr_sfinae | |
5016 | (t, tf_none) followed by maybe_constant_value but is more efficient, | |
5017 | because calls instantiation_dependent_expression_p and | |
5018 | potential_constant_expression at most once. */ | |
5019 | ||
5020 | tree | |
5021 | fold_non_dependent_expr (tree t) | |
5022 | { | |
5023 | if (t == NULL_TREE) | |
5024 | return NULL_TREE; | |
5025 | ||
5026 | /* If we're in a template, but T isn't value dependent, simplify | |
5027 | it. We're supposed to treat: | |
5028 | ||
5029 | template <typename T> void f(T[1 + 1]); | |
5030 | template <typename T> void f(T[2]); | |
5031 | ||
5032 | as two declarations of the same function, for example. */ | |
5033 | if (processing_template_decl) | |
5034 | { | |
7e1f8be4 | 5035 | if (is_nondependent_constant_expression (t)) |
21131a05 | 5036 | { |
c8a9f04c | 5037 | processing_template_decl_sentinel s; |
5038 | t = instantiate_non_dependent_expr_internal (t, tf_none); | |
21131a05 | 5039 | |
5040 | if (type_unknown_p (t) | |
5041 | || BRACE_ENCLOSED_INITIALIZER_P (t)) | |
5042 | { | |
5043 | if (TREE_OVERFLOW_P (t)) | |
5044 | { | |
5045 | t = build_nop (TREE_TYPE (t), t); | |
5046 | TREE_CONSTANT (t) = false; | |
5047 | } | |
5048 | return t; | |
5049 | } | |
5050 | ||
2055d27a | 5051 | tree r = cxx_eval_outermost_constant_expr (t, true, true, NULL_TREE); |
21131a05 | 5052 | /* cp_tree_equal looks through NOPs, so allow them. */ |
5e8689fb | 5053 | gcc_checking_assert (r == t |
5054 | || CONVERT_EXPR_P (t) | |
5055 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
5056 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
5057 | || !cp_tree_equal (r, t)); | |
21131a05 | 5058 | return r; |
5059 | } | |
5060 | else if (TREE_OVERFLOW_P (t)) | |
5061 | { | |
5062 | t = build_nop (TREE_TYPE (t), t); | |
5063 | TREE_CONSTANT (t) = false; | |
5064 | } | |
5065 | return t; | |
5066 | } | |
5067 | ||
5068 | return maybe_constant_value (t); | |
5069 | } | |
5070 | ||
09b42213 | 5071 | /* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather |
5072 | than wrapped in a TARGET_EXPR. */ | |
5073 | ||
5074 | tree | |
cf72f34d | 5075 | maybe_constant_init (tree t, tree decl) |
09b42213 | 5076 | { |
d2c63826 | 5077 | if (!t) |
5078 | return t; | |
09b42213 | 5079 | if (TREE_CODE (t) == EXPR_STMT) |
5080 | t = TREE_OPERAND (t, 0); | |
5081 | if (TREE_CODE (t) == CONVERT_EXPR | |
5082 | && VOID_TYPE_P (TREE_TYPE (t))) | |
5083 | t = TREE_OPERAND (t, 0); | |
9c96033c | 5084 | if (TREE_CODE (t) == INIT_EXPR) |
5085 | t = TREE_OPERAND (t, 1); | |
c6d97004 | 5086 | if (TREE_CODE (t) == TARGET_EXPR) |
5087 | t = TARGET_EXPR_INITIAL (t); | |
7e1f8be4 | 5088 | if (!is_nondependent_static_init_expression (t)) |
2055d27a | 5089 | /* Don't try to evaluate it. */; |
b601ad30 | 5090 | else if (CONSTANT_CLASS_P (t)) |
5091 | /* No evaluation needed. */; | |
2055d27a | 5092 | else |
5093 | t = cxx_eval_outermost_constant_expr (t, true, false, decl); | |
09b42213 | 5094 | if (TREE_CODE (t) == TARGET_EXPR) |
5095 | { | |
5096 | tree init = TARGET_EXPR_INITIAL (t); | |
5097 | if (TREE_CODE (init) == CONSTRUCTOR) | |
5098 | t = init; | |
5099 | } | |
5100 | return t; | |
5101 | } | |
5102 | ||
5103 | #if 0 | |
5104 | /* FIXME see ADDR_EXPR section in potential_constant_expression_1. */ | |
5105 | /* Return true if the object referred to by REF has automatic or thread | |
5106 | local storage. */ | |
5107 | ||
5108 | enum { ck_ok, ck_bad, ck_unknown }; | |
5109 | static int | |
5110 | check_automatic_or_tls (tree ref) | |
5111 | { | |
3754d046 | 5112 | machine_mode mode; |
09b42213 | 5113 | HOST_WIDE_INT bitsize, bitpos; |
5114 | tree offset; | |
5115 | int volatilep = 0, unsignedp = 0; | |
5116 | tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset, | |
5117 | &mode, &unsignedp, &volatilep, false); | |
5118 | duration_kind dk; | |
5119 | ||
5120 | /* If there isn't a decl in the middle, we don't know the linkage here, | |
5121 | and this isn't a constant expression anyway. */ | |
5122 | if (!DECL_P (decl)) | |
5123 | return ck_unknown; | |
5124 | dk = decl_storage_duration (decl); | |
5125 | return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok; | |
5126 | } | |
5127 | #endif | |
5128 | ||
5129 | /* Return true if T denotes a potentially constant expression. Issue | |
5130 | diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true, | |
7e1f8be4 | 5131 | an lvalue-rvalue conversion is implied. If NOW is true, we want to |
5132 | consider the expression in the current context, independent of constexpr | |
5133 | substitution. | |
09b42213 | 5134 | |
5135 | C++0x [expr.const] used to say | |
5136 | ||
5137 | 6 An expression is a potential constant expression if it is | |
5138 | a constant expression where all occurrences of function | |
5139 | parameters are replaced by arbitrary constant expressions | |
5140 | of the appropriate type. | |
5141 | ||
5142 | 2 A conditional expression is a constant expression unless it | |
5143 | involves one of the following as a potentially evaluated | |
5144 | subexpression (3.2), but subexpressions of logical AND (5.14), | |
5145 | logical OR (5.15), and conditional (5.16) operations that are | |
5146 | not evaluated are not considered. */ | |
5147 | ||
5148 | static bool | |
7e1f8be4 | 5149 | potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, |
2055d27a | 5150 | tsubst_flags_t flags) |
09b42213 | 5151 | { |
7e1f8be4 | 5152 | #define RECUR(T,RV) \ |
5153 | potential_constant_expression_1 ((T), (RV), strict, now, flags) | |
5154 | ||
09b42213 | 5155 | enum { any = false, rval = true }; |
5156 | int i; | |
5157 | tree tmp; | |
5158 | ||
5159 | if (t == error_mark_node) | |
5160 | return false; | |
5161 | if (t == NULL_TREE) | |
5162 | return true; | |
d6a08f5c | 5163 | location_t loc = EXPR_LOC_OR_LOC (t, input_location); |
eade0940 | 5164 | if (TREE_THIS_VOLATILE (t) && !DECL_P (t)) |
09b42213 | 5165 | { |
5166 | if (flags & tf_error) | |
d6a08f5c | 5167 | error_at (loc, "expression %qE has side-effects", t); |
09b42213 | 5168 | return false; |
5169 | } | |
5170 | if (CONSTANT_CLASS_P (t)) | |
5171 | return true; | |
c7282bf2 | 5172 | if (CODE_CONTAINS_STRUCT (TREE_CODE (t), TS_TYPED) |
5173 | && TREE_TYPE (t) == error_mark_node) | |
5174 | return false; | |
09b42213 | 5175 | |
5176 | switch (TREE_CODE (t)) | |
5177 | { | |
5178 | case FUNCTION_DECL: | |
5179 | case BASELINK: | |
5180 | case TEMPLATE_DECL: | |
5181 | case OVERLOAD: | |
5182 | case TEMPLATE_ID_EXPR: | |
5183 | case LABEL_DECL: | |
5184 | case LABEL_EXPR: | |
9c96033c | 5185 | case CASE_LABEL_EXPR: |
09b42213 | 5186 | case CONST_DECL: |
5187 | case SIZEOF_EXPR: | |
5188 | case ALIGNOF_EXPR: | |
5189 | case OFFSETOF_EXPR: | |
5190 | case NOEXCEPT_EXPR: | |
5191 | case TEMPLATE_PARM_INDEX: | |
5192 | case TRAIT_EXPR: | |
5193 | case IDENTIFIER_NODE: | |
5194 | case USERDEF_LITERAL: | |
5195 | /* We can see a FIELD_DECL in a pointer-to-member expression. */ | |
5196 | case FIELD_DECL: | |
d2c63826 | 5197 | case RESULT_DECL: |
09b42213 | 5198 | case USING_DECL: |
9c96033c | 5199 | case USING_STMT: |
cf72f34d | 5200 | case PLACEHOLDER_EXPR: |
9c96033c | 5201 | case BREAK_STMT: |
5202 | case CONTINUE_STMT: | |
56c12fd4 | 5203 | case REQUIRES_EXPR: |
33603066 | 5204 | case STATIC_ASSERT: |
90567983 | 5205 | case DEBUG_BEGIN_STMT: |
09b42213 | 5206 | return true; |
5207 | ||
7e1f8be4 | 5208 | case PARM_DECL: |
5209 | if (now) | |
5210 | { | |
5211 | if (flags & tf_error) | |
5212 | error ("%qE is not a constant expression", t); | |
5213 | return false; | |
5214 | } | |
5215 | return true; | |
5216 | ||
09b42213 | 5217 | case AGGR_INIT_EXPR: |
5218 | case CALL_EXPR: | |
5219 | /* -- an invocation of a function other than a constexpr function | |
5220 | or a constexpr constructor. */ | |
5221 | { | |
5222 | tree fun = get_function_named_in_call (t); | |
5223 | const int nargs = call_expr_nargs (t); | |
5224 | i = 0; | |
5225 | ||
9c96033c | 5226 | if (fun == NULL_TREE) |
5227 | { | |
732905bb | 5228 | /* Reset to allow the function to continue past the end |
5229 | of the block below. Otherwise return early. */ | |
5230 | bool bail = true; | |
5231 | ||
32cf7025 | 5232 | if (TREE_CODE (t) == CALL_EXPR |
5233 | && CALL_EXPR_FN (t) == NULL_TREE) | |
5234 | switch (CALL_EXPR_IFN (t)) | |
5235 | { | |
5236 | /* These should be ignored, they are optimized away from | |
5237 | constexpr functions. */ | |
5238 | case IFN_UBSAN_NULL: | |
5239 | case IFN_UBSAN_BOUNDS: | |
5240 | case IFN_UBSAN_VPTR: | |
3c77f69c | 5241 | case IFN_FALLTHROUGH: |
32cf7025 | 5242 | return true; |
732905bb | 5243 | |
5244 | case IFN_ADD_OVERFLOW: | |
5245 | case IFN_SUB_OVERFLOW: | |
5246 | case IFN_MUL_OVERFLOW: | |
6e1b2ffb | 5247 | case IFN_LAUNDER: |
732905bb | 5248 | bail = false; |
5249 | ||
32cf7025 | 5250 | default: |
5251 | break; | |
5252 | } | |
732905bb | 5253 | |
5254 | if (bail) | |
5255 | { | |
5256 | /* fold_call_expr can't do anything with IFN calls. */ | |
5257 | if (flags & tf_error) | |
d6a08f5c | 5258 | error_at (loc, "call to internal function %qE", t); |
732905bb | 5259 | return false; |
5260 | } | |
9c96033c | 5261 | } |
732905bb | 5262 | |
5263 | if (fun && is_overloaded_fn (fun)) | |
09b42213 | 5264 | { |
5265 | if (TREE_CODE (fun) == FUNCTION_DECL) | |
5266 | { | |
5267 | if (builtin_valid_in_constant_expr_p (fun)) | |
5268 | return true; | |
5269 | if (!DECL_DECLARED_CONSTEXPR_P (fun) | |
5270 | /* Allow any built-in function; if the expansion | |
5271 | isn't constant, we'll deal with that then. */ | |
5272 | && !is_builtin_fn (fun)) | |
5273 | { | |
5274 | if (flags & tf_error) | |
5275 | { | |
5967b28b | 5276 | error_at (loc, "call to non-%<constexpr%> function %qD", |
d6a08f5c | 5277 | fun); |
09b42213 | 5278 | explain_invalid_constexpr_fn (fun); |
5279 | } | |
5280 | return false; | |
5281 | } | |
5282 | /* A call to a non-static member function takes the address | |
5283 | of the object as the first argument. But in a constant | |
5284 | expression the address will be folded away, so look | |
5285 | through it now. */ | |
5286 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
5287 | && !DECL_CONSTRUCTOR_P (fun)) | |
5288 | { | |
5289 | tree x = get_nth_callarg (t, 0); | |
5290 | if (is_this_parameter (x)) | |
cf72f34d | 5291 | return true; |
7e1f8be4 | 5292 | /* Don't require an immediately constant value, as |
5293 | constexpr substitution might not use the value. */ | |
5294 | bool sub_now = false; | |
5295 | if (!potential_constant_expression_1 (x, rval, strict, | |
5296 | sub_now, flags)) | |
09b42213 | 5297 | return false; |
5298 | i = 1; | |
5299 | } | |
5300 | } | |
5301 | else | |
5302 | { | |
2055d27a | 5303 | if (!RECUR (fun, true)) |
09b42213 | 5304 | return false; |
5305 | fun = get_first_fn (fun); | |
5306 | } | |
5307 | /* Skip initial arguments to base constructors. */ | |
5308 | if (DECL_BASE_CONSTRUCTOR_P (fun)) | |
5309 | i = num_artificial_parms_for (fun); | |
5310 | fun = DECL_ORIGIN (fun); | |
5311 | } | |
732905bb | 5312 | else if (fun) |
09b42213 | 5313 | { |
2055d27a | 5314 | if (RECUR (fun, rval)) |
09b42213 | 5315 | /* Might end up being a constant function pointer. */; |
5316 | else | |
5317 | return false; | |
5318 | } | |
5319 | for (; i < nargs; ++i) | |
5320 | { | |
5321 | tree x = get_nth_callarg (t, i); | |
b2742b58 | 5322 | /* In a template, reference arguments haven't been converted to |
5323 | REFERENCE_TYPE and we might not even know if the parameter | |
5324 | is a reference, so accept lvalue constants too. */ | |
5325 | bool rv = processing_template_decl ? any : rval; | |
7e1f8be4 | 5326 | /* Don't require an immediately constant value, as constexpr |
5327 | substitution might not use the value of the argument. */ | |
5328 | bool sub_now = false; | |
5329 | if (!potential_constant_expression_1 (x, rv, strict, | |
5330 | sub_now, flags)) | |
09b42213 | 5331 | return false; |
5332 | } | |
5333 | return true; | |
5334 | } | |
5335 | ||
5336 | case NON_LVALUE_EXPR: | |
5337 | /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to | |
5338 | -- an lvalue of integral type that refers to a non-volatile | |
5339 | const variable or static data member initialized with | |
5340 | constant expressions, or | |
5341 | ||
5342 | -- an lvalue of literal type that refers to non-volatile | |
5343 | object defined with constexpr, or that refers to a | |
5344 | sub-object of such an object; */ | |
2055d27a | 5345 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 5346 | |
5347 | case VAR_DECL: | |
9c8aeb66 | 5348 | if (DECL_HAS_VALUE_EXPR_P (t)) |
297de7bc | 5349 | { |
5350 | if (now && is_normal_capture_proxy (t)) | |
5351 | { | |
5352 | /* -- in a lambda-expression, a reference to this or to a | |
5353 | variable with automatic storage duration defined outside that | |
5354 | lambda-expression, where the reference would be an | |
5355 | odr-use. */ | |
5356 | if (flags & tf_error) | |
5357 | { | |
5358 | tree cap = DECL_CAPTURED_VARIABLE (t); | |
5359 | error ("lambda capture of %qE is not a constant expression", | |
5360 | cap); | |
5361 | if (!want_rval && decl_constant_var_p (cap)) | |
5362 | inform (input_location, "because it is used as a glvalue"); | |
5363 | } | |
5364 | return false; | |
5365 | } | |
5366 | return RECUR (DECL_VALUE_EXPR (t), rval); | |
5367 | } | |
2055d27a | 5368 | if (want_rval |
33603066 | 5369 | && !var_in_maybe_constexpr_fn (t) |
c7282bf2 | 5370 | && !type_dependent_expression_p (t) |
8d6486e1 | 5371 | && !decl_maybe_constant_var_p (t) |
2055d27a | 5372 | && (strict |
5373 | || !CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (t)) | |
8d6486e1 | 5374 | || (DECL_INITIAL (t) |
5375 | && !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (t))) | |
c7282bf2 | 5376 | && COMPLETE_TYPE_P (TREE_TYPE (t)) |
5377 | && !is_really_empty_class (TREE_TYPE (t))) | |
09b42213 | 5378 | { |
5379 | if (flags & tf_error) | |
5380 | non_const_var_error (t); | |
5381 | return false; | |
5382 | } | |
5383 | return true; | |
5384 | ||
5385 | case NOP_EXPR: | |
5386 | case CONVERT_EXPR: | |
5387 | case VIEW_CONVERT_EXPR: | |
5388 | /* -- a reinterpret_cast. FIXME not implemented, and this rule | |
5389 | may change to something more specific to type-punning (DR 1312). */ | |
5390 | { | |
5391 | tree from = TREE_OPERAND (t, 0); | |
5392 | if (POINTER_TYPE_P (TREE_TYPE (t)) | |
5393 | && TREE_CODE (from) == INTEGER_CST | |
5394 | && !integer_zerop (from)) | |
5395 | { | |
5396 | if (flags & tf_error) | |
d6a08f5c | 5397 | error_at (loc, "reinterpret_cast from integer to pointer"); |
09b42213 | 5398 | return false; |
5399 | } | |
2055d27a | 5400 | return (RECUR (from, TREE_CODE (t) != VIEW_CONVERT_EXPR)); |
09b42213 | 5401 | } |
5402 | ||
cd45162d | 5403 | case ADDRESSOF_EXPR: |
5404 | /* This is like ADDR_EXPR, except it won't form pointer-to-member. */ | |
5405 | t = TREE_OPERAND (t, 0); | |
5406 | goto handle_addr_expr; | |
5407 | ||
09b42213 | 5408 | case ADDR_EXPR: |
5409 | /* -- a unary operator & that is applied to an lvalue that | |
5410 | designates an object with thread or automatic storage | |
5411 | duration; */ | |
5412 | t = TREE_OPERAND (t, 0); | |
5413 | ||
5414 | if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t)) | |
5415 | /* A pointer-to-member constant. */ | |
5416 | return true; | |
5417 | ||
cd45162d | 5418 | handle_addr_expr: |
09b42213 | 5419 | #if 0 |
5420 | /* FIXME adjust when issue 1197 is fully resolved. For now don't do | |
5421 | any checking here, as we might dereference the pointer later. If | |
5422 | we remove this code, also remove check_automatic_or_tls. */ | |
5423 | i = check_automatic_or_tls (t); | |
5424 | if (i == ck_ok) | |
5425 | return true; | |
5426 | if (i == ck_bad) | |
5427 | { | |
5428 | if (flags & tf_error) | |
5429 | error ("address-of an object %qE with thread local or " | |
5430 | "automatic storage is not a constant expression", t); | |
5431 | return false; | |
5432 | } | |
5433 | #endif | |
2055d27a | 5434 | return RECUR (t, any); |
09b42213 | 5435 | |
20b34a56 | 5436 | case REALPART_EXPR: |
5437 | case IMAGPART_EXPR: | |
09b42213 | 5438 | case COMPONENT_REF: |
5439 | case BIT_FIELD_REF: | |
5440 | case ARROW_EXPR: | |
5441 | case OFFSET_REF: | |
5442 | /* -- a class member access unless its postfix-expression is | |
5443 | of literal type or of pointer to literal type. */ | |
5444 | /* This test would be redundant, as it follows from the | |
5445 | postfix-expression being a potential constant expression. */ | |
eade0940 | 5446 | if (type_unknown_p (t)) |
5447 | return true; | |
2055d27a | 5448 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5449 | |
5450 | case EXPR_PACK_EXPANSION: | |
2055d27a | 5451 | return RECUR (PACK_EXPANSION_PATTERN (t), want_rval); |
09b42213 | 5452 | |
5453 | case INDIRECT_REF: | |
5454 | { | |
5455 | tree x = TREE_OPERAND (t, 0); | |
5456 | STRIP_NOPS (x); | |
997bbf70 | 5457 | if (is_this_parameter (x) && !is_capture_proxy (x)) |
09b42213 | 5458 | { |
b7e4a558 | 5459 | if (!var_in_maybe_constexpr_fn (x)) |
09b42213 | 5460 | { |
5461 | if (flags & tf_error) | |
d6a08f5c | 5462 | error_at (loc, "use of %<this%> in a constant expression"); |
09b42213 | 5463 | return false; |
5464 | } | |
09b42213 | 5465 | return true; |
5466 | } | |
2055d27a | 5467 | return RECUR (x, rval); |
09b42213 | 5468 | } |
5469 | ||
9c96033c | 5470 | case STATEMENT_LIST: |
5471 | { | |
5472 | tree_stmt_iterator i; | |
5473 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
5474 | { | |
2055d27a | 5475 | if (!RECUR (tsi_stmt (i), any)) |
9c96033c | 5476 | return false; |
5477 | } | |
5478 | return true; | |
5479 | } | |
5480 | break; | |
5481 | ||
5482 | case MODIFY_EXPR: | |
5483 | if (cxx_dialect < cxx14) | |
5484 | goto fail; | |
2055d27a | 5485 | if (!RECUR (TREE_OPERAND (t, 0), any)) |
9c96033c | 5486 | return false; |
2055d27a | 5487 | if (!RECUR (TREE_OPERAND (t, 1), rval)) |
9c96033c | 5488 | return false; |
5489 | return true; | |
5490 | ||
5491 | case MODOP_EXPR: | |
5492 | if (cxx_dialect < cxx14) | |
5493 | goto fail; | |
2055d27a | 5494 | if (!RECUR (TREE_OPERAND (t, 0), rval)) |
9c96033c | 5495 | return false; |
2055d27a | 5496 | if (!RECUR (TREE_OPERAND (t, 2), rval)) |
9c96033c | 5497 | return false; |
5498 | return true; | |
5499 | ||
9c96033c | 5500 | case DO_STMT: |
2055d27a | 5501 | if (!RECUR (DO_COND (t), rval)) |
9c96033c | 5502 | return false; |
2055d27a | 5503 | if (!RECUR (DO_BODY (t), any)) |
9c96033c | 5504 | return false; |
5505 | return true; | |
5506 | ||
5507 | case FOR_STMT: | |
2055d27a | 5508 | if (!RECUR (FOR_INIT_STMT (t), any)) |
9c96033c | 5509 | return false; |
2055d27a | 5510 | if (!RECUR (FOR_COND (t), rval)) |
9c96033c | 5511 | return false; |
2055d27a | 5512 | if (!RECUR (FOR_EXPR (t), any)) |
9c96033c | 5513 | return false; |
2055d27a | 5514 | if (!RECUR (FOR_BODY (t), any)) |
9c96033c | 5515 | return false; |
5516 | return true; | |
5517 | ||
33603066 | 5518 | case RANGE_FOR_STMT: |
5519 | if (!RECUR (RANGE_FOR_EXPR (t), any)) | |
5520 | return false; | |
5521 | if (!RECUR (RANGE_FOR_BODY (t), any)) | |
5522 | return false; | |
5523 | return true; | |
5524 | ||
9c96033c | 5525 | case WHILE_STMT: |
2055d27a | 5526 | if (!RECUR (WHILE_COND (t), rval)) |
9c96033c | 5527 | return false; |
2055d27a | 5528 | if (!RECUR (WHILE_BODY (t), any)) |
9c96033c | 5529 | return false; |
5530 | return true; | |
5531 | ||
5532 | case SWITCH_STMT: | |
2055d27a | 5533 | if (!RECUR (SWITCH_STMT_COND (t), rval)) |
9c96033c | 5534 | return false; |
748c426a | 5535 | /* FIXME we don't check SWITCH_STMT_BODY currently, because even |
5536 | unreachable labels would be checked. */ | |
9c96033c | 5537 | return true; |
5538 | ||
da7981e0 | 5539 | case STMT_EXPR: |
2055d27a | 5540 | return RECUR (STMT_EXPR_STMT (t), rval); |
da7981e0 | 5541 | |
09b42213 | 5542 | case LAMBDA_EXPR: |
27db1f50 | 5543 | if (cxx_dialect >= cxx17) |
5544 | /* In C++17 lambdas can be constexpr, don't give up yet. */ | |
5545 | return true; | |
5546 | else if (flags & tf_error) | |
5547 | error_at (loc, "lambda-expression is not a constant expression " | |
5548 | "before C++17"); | |
5549 | return false; | |
5550 | ||
09b42213 | 5551 | case DYNAMIC_CAST_EXPR: |
5552 | case PSEUDO_DTOR_EXPR: | |
09b42213 | 5553 | case NEW_EXPR: |
5554 | case VEC_NEW_EXPR: | |
5555 | case DELETE_EXPR: | |
5556 | case VEC_DELETE_EXPR: | |
5557 | case THROW_EXPR: | |
d6a08f5c | 5558 | case OMP_PARALLEL: |
5559 | case OMP_TASK: | |
5560 | case OMP_FOR: | |
5561 | case OMP_DISTRIBUTE: | |
5562 | case OMP_TASKLOOP: | |
5563 | case OMP_TEAMS: | |
5564 | case OMP_TARGET_DATA: | |
5565 | case OMP_TARGET: | |
5566 | case OMP_SECTIONS: | |
5567 | case OMP_ORDERED: | |
5568 | case OMP_CRITICAL: | |
5569 | case OMP_SINGLE: | |
5570 | case OMP_SECTION: | |
5571 | case OMP_MASTER: | |
5572 | case OMP_TASKGROUP: | |
5573 | case OMP_TARGET_UPDATE: | |
5574 | case OMP_TARGET_ENTER_DATA: | |
5575 | case OMP_TARGET_EXIT_DATA: | |
09b42213 | 5576 | case OMP_ATOMIC: |
5577 | case OMP_ATOMIC_READ: | |
5578 | case OMP_ATOMIC_CAPTURE_OLD: | |
5579 | case OMP_ATOMIC_CAPTURE_NEW: | |
d6a08f5c | 5580 | case OACC_PARALLEL: |
5581 | case OACC_KERNELS: | |
5582 | case OACC_DATA: | |
5583 | case OACC_HOST_DATA: | |
5584 | case OACC_LOOP: | |
5585 | case OACC_CACHE: | |
5586 | case OACC_DECLARE: | |
5587 | case OACC_ENTER_DATA: | |
5588 | case OACC_EXIT_DATA: | |
5589 | case OACC_UPDATE: | |
09b42213 | 5590 | /* GCC internal stuff. */ |
5591 | case VA_ARG_EXPR: | |
5592 | case OBJ_TYPE_REF: | |
09b42213 | 5593 | case TRANSACTION_EXPR: |
9c96033c | 5594 | case ASM_EXPR: |
9abecca2 | 5595 | case AT_ENCODE_EXPR: |
9c96033c | 5596 | fail: |
09b42213 | 5597 | if (flags & tf_error) |
d6a08f5c | 5598 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 5599 | return false; |
5600 | ||
5601 | case TYPEID_EXPR: | |
5602 | /* -- a typeid expression whose operand is of polymorphic | |
5603 | class type; */ | |
5604 | { | |
5605 | tree e = TREE_OPERAND (t, 0); | |
5606 | if (!TYPE_P (e) && !type_dependent_expression_p (e) | |
5607 | && TYPE_POLYMORPHIC_P (TREE_TYPE (e))) | |
5608 | { | |
5609 | if (flags & tf_error) | |
d6a08f5c | 5610 | error_at (loc, "typeid-expression is not a constant expression " |
5611 | "because %qE is of polymorphic type", e); | |
09b42213 | 5612 | return false; |
5613 | } | |
5614 | return true; | |
5615 | } | |
5616 | ||
57e83b58 | 5617 | case POINTER_DIFF_EXPR: |
09b42213 | 5618 | case MINUS_EXPR: |
09b42213 | 5619 | want_rval = true; |
5620 | goto binary; | |
5621 | ||
5622 | case LT_EXPR: | |
5623 | case LE_EXPR: | |
5624 | case GT_EXPR: | |
5625 | case GE_EXPR: | |
5626 | case EQ_EXPR: | |
5627 | case NE_EXPR: | |
09b42213 | 5628 | want_rval = true; |
5629 | goto binary; | |
5630 | ||
9c96033c | 5631 | case PREINCREMENT_EXPR: |
5632 | case POSTINCREMENT_EXPR: | |
5633 | case PREDECREMENT_EXPR: | |
5634 | case POSTDECREMENT_EXPR: | |
5635 | if (cxx_dialect < cxx14) | |
5636 | goto fail; | |
5637 | goto unary; | |
5638 | ||
09b42213 | 5639 | case BIT_NOT_EXPR: |
5640 | /* A destructor. */ | |
5641 | if (TYPE_P (TREE_OPERAND (t, 0))) | |
5642 | return true; | |
e3533433 | 5643 | /* fall through. */ |
09b42213 | 5644 | |
09b42213 | 5645 | case CONJ_EXPR: |
5646 | case SAVE_EXPR: | |
5647 | case FIX_TRUNC_EXPR: | |
5648 | case FLOAT_EXPR: | |
5649 | case NEGATE_EXPR: | |
5650 | case ABS_EXPR: | |
5651 | case TRUTH_NOT_EXPR: | |
5652 | case FIXED_CONVERT_EXPR: | |
5653 | case UNARY_PLUS_EXPR: | |
6fdf70f5 | 5654 | case UNARY_LEFT_FOLD_EXPR: |
5655 | case UNARY_RIGHT_FOLD_EXPR: | |
9c96033c | 5656 | unary: |
2055d27a | 5657 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 5658 | |
5659 | case CAST_EXPR: | |
5660 | case CONST_CAST_EXPR: | |
5661 | case STATIC_CAST_EXPR: | |
5662 | case REINTERPRET_CAST_EXPR: | |
5663 | case IMPLICIT_CONV_EXPR: | |
5664 | if (cxx_dialect < cxx11 | |
5665 | && !dependent_type_p (TREE_TYPE (t)) | |
5666 | && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t))) | |
5667 | /* In C++98, a conversion to non-integral type can't be part of a | |
5668 | constant expression. */ | |
5669 | { | |
5670 | if (flags & tf_error) | |
d6a08f5c | 5671 | error_at (loc, |
5672 | "cast to non-integral type %qT in a constant expression", | |
5673 | TREE_TYPE (t)); | |
09b42213 | 5674 | return false; |
5675 | } | |
5676 | ||
2055d27a | 5677 | return (RECUR (TREE_OPERAND (t, 0), |
5678 | TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE)); | |
09b42213 | 5679 | |
9c96033c | 5680 | case BIND_EXPR: |
2055d27a | 5681 | return RECUR (BIND_EXPR_BODY (t), want_rval); |
9c96033c | 5682 | |
9c96033c | 5683 | case CLEANUP_POINT_EXPR: |
5684 | case MUST_NOT_THROW_EXPR: | |
5685 | case TRY_CATCH_EXPR: | |
7f67d68c | 5686 | case TRY_BLOCK: |
9c96033c | 5687 | case EH_SPEC_BLOCK: |
5688 | case EXPR_STMT: | |
09b42213 | 5689 | case PAREN_EXPR: |
5690 | case NON_DEPENDENT_EXPR: | |
5691 | /* For convenience. */ | |
5692 | case RETURN_EXPR: | |
d1980671 | 5693 | case LOOP_EXPR: |
5694 | case EXIT_EXPR: | |
2055d27a | 5695 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5696 | |
33603066 | 5697 | case DECL_EXPR: |
5698 | tmp = DECL_EXPR_DECL (t); | |
5699 | if (VAR_P (tmp) && !DECL_ARTIFICIAL (tmp)) | |
5700 | { | |
5701 | if (TREE_STATIC (tmp)) | |
5702 | { | |
5703 | if (flags & tf_error) | |
5704 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 5705 | "%<static%> in %<constexpr%> context", tmp); |
33603066 | 5706 | return false; |
5707 | } | |
5708 | else if (CP_DECL_THREAD_LOCAL_P (tmp)) | |
5709 | { | |
5710 | if (flags & tf_error) | |
5711 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 5712 | "%<thread_local%> in %<constexpr%> context", tmp); |
33603066 | 5713 | return false; |
5714 | } | |
5715 | else if (!DECL_NONTRIVIALLY_INITIALIZED_P (tmp)) | |
5716 | { | |
5717 | if (flags & tf_error) | |
5718 | error_at (DECL_SOURCE_LOCATION (tmp), "uninitialized " | |
8d6486e1 | 5719 | "variable %qD in %<constexpr%> context", tmp); |
33603066 | 5720 | return false; |
5721 | } | |
5722 | } | |
5723 | return RECUR (tmp, want_rval); | |
5724 | ||
7f67d68c | 5725 | case TRY_FINALLY_EXPR: |
5726 | return (RECUR (TREE_OPERAND (t, 0), want_rval) | |
5727 | && RECUR (TREE_OPERAND (t, 1), any)); | |
5728 | ||
09b42213 | 5729 | case SCOPE_REF: |
2055d27a | 5730 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 5731 | |
5732 | case TARGET_EXPR: | |
5733 | if (!literal_type_p (TREE_TYPE (t))) | |
5734 | { | |
5735 | if (flags & tf_error) | |
5736 | { | |
d6a08f5c | 5737 | error_at (loc, "temporary of non-literal type %qT in a " |
5738 | "constant expression", TREE_TYPE (t)); | |
09b42213 | 5739 | explain_non_literal_class (TREE_TYPE (t)); |
5740 | } | |
5741 | return false; | |
5742 | } | |
e3533433 | 5743 | /* FALLTHRU */ |
09b42213 | 5744 | case INIT_EXPR: |
2055d27a | 5745 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 5746 | |
5747 | case CONSTRUCTOR: | |
5748 | { | |
5749 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
5750 | constructor_elt *ce; | |
5751 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2055d27a | 5752 | if (!RECUR (ce->value, want_rval)) |
09b42213 | 5753 | return false; |
5754 | return true; | |
5755 | } | |
5756 | ||
5757 | case TREE_LIST: | |
5758 | { | |
5759 | gcc_assert (TREE_PURPOSE (t) == NULL_TREE | |
5760 | || DECL_P (TREE_PURPOSE (t))); | |
2055d27a | 5761 | if (!RECUR (TREE_VALUE (t), want_rval)) |
09b42213 | 5762 | return false; |
5763 | if (TREE_CHAIN (t) == NULL_TREE) | |
5764 | return true; | |
2055d27a | 5765 | return RECUR (TREE_CHAIN (t), want_rval); |
09b42213 | 5766 | } |
5767 | ||
5768 | case TRUNC_DIV_EXPR: | |
5769 | case CEIL_DIV_EXPR: | |
5770 | case FLOOR_DIV_EXPR: | |
5771 | case ROUND_DIV_EXPR: | |
5772 | case TRUNC_MOD_EXPR: | |
5773 | case CEIL_MOD_EXPR: | |
5774 | case ROUND_MOD_EXPR: | |
5775 | { | |
5776 | tree denom = TREE_OPERAND (t, 1); | |
2055d27a | 5777 | if (!RECUR (denom, rval)) |
09b42213 | 5778 | return false; |
5779 | /* We can't call cxx_eval_outermost_constant_expr on an expression | |
21131a05 | 5780 | that hasn't been through instantiate_non_dependent_expr yet. */ |
09b42213 | 5781 | if (!processing_template_decl) |
5782 | denom = cxx_eval_outermost_constant_expr (denom, true); | |
5783 | if (integer_zerop (denom)) | |
5784 | { | |
5785 | if (flags & tf_error) | |
ea034e2c | 5786 | error ("division by zero is not a constant expression"); |
09b42213 | 5787 | return false; |
5788 | } | |
5789 | else | |
5790 | { | |
5791 | want_rval = true; | |
2055d27a | 5792 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5793 | } |
5794 | } | |
5795 | ||
5796 | case COMPOUND_EXPR: | |
5797 | { | |
5798 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
5799 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
5800 | introduced by build_call_a. */ | |
5801 | tree op0 = TREE_OPERAND (t, 0); | |
5802 | tree op1 = TREE_OPERAND (t, 1); | |
5803 | STRIP_NOPS (op1); | |
5804 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
5805 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
2055d27a | 5806 | return RECUR (op0, want_rval); |
09b42213 | 5807 | else |
5808 | goto binary; | |
5809 | } | |
5810 | ||
5811 | /* If the first operand is the non-short-circuit constant, look at | |
5812 | the second operand; otherwise we only care about the first one for | |
5813 | potentiality. */ | |
5814 | case TRUTH_AND_EXPR: | |
5815 | case TRUTH_ANDIF_EXPR: | |
5816 | tmp = boolean_true_node; | |
5817 | goto truth; | |
5818 | case TRUTH_OR_EXPR: | |
5819 | case TRUTH_ORIF_EXPR: | |
5820 | tmp = boolean_false_node; | |
5821 | truth: | |
5822 | { | |
5823 | tree op = TREE_OPERAND (t, 0); | |
2055d27a | 5824 | if (!RECUR (op, rval)) |
09b42213 | 5825 | return false; |
5826 | if (!processing_template_decl) | |
5827 | op = cxx_eval_outermost_constant_expr (op, true); | |
5828 | if (tree_int_cst_equal (op, tmp)) | |
2055d27a | 5829 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 5830 | else |
5831 | return true; | |
5832 | } | |
5833 | ||
5834 | case PLUS_EXPR: | |
5835 | case MULT_EXPR: | |
5836 | case POINTER_PLUS_EXPR: | |
5837 | case RDIV_EXPR: | |
5838 | case EXACT_DIV_EXPR: | |
5839 | case MIN_EXPR: | |
5840 | case MAX_EXPR: | |
5841 | case LSHIFT_EXPR: | |
5842 | case RSHIFT_EXPR: | |
5843 | case LROTATE_EXPR: | |
5844 | case RROTATE_EXPR: | |
5845 | case BIT_IOR_EXPR: | |
5846 | case BIT_XOR_EXPR: | |
5847 | case BIT_AND_EXPR: | |
5848 | case TRUTH_XOR_EXPR: | |
5849 | case UNORDERED_EXPR: | |
5850 | case ORDERED_EXPR: | |
5851 | case UNLT_EXPR: | |
5852 | case UNLE_EXPR: | |
5853 | case UNGT_EXPR: | |
5854 | case UNGE_EXPR: | |
5855 | case UNEQ_EXPR: | |
5856 | case LTGT_EXPR: | |
5857 | case RANGE_EXPR: | |
5858 | case COMPLEX_EXPR: | |
5859 | want_rval = true; | |
5860 | /* Fall through. */ | |
5861 | case ARRAY_REF: | |
5862 | case ARRAY_RANGE_REF: | |
5863 | case MEMBER_REF: | |
5864 | case DOTSTAR_EXPR: | |
f0abe78f | 5865 | case MEM_REF: |
6fdf70f5 | 5866 | case BINARY_LEFT_FOLD_EXPR: |
5867 | case BINARY_RIGHT_FOLD_EXPR: | |
09b42213 | 5868 | binary: |
5869 | for (i = 0; i < 2; ++i) | |
2055d27a | 5870 | if (!RECUR (TREE_OPERAND (t, i), want_rval)) |
09b42213 | 5871 | return false; |
5872 | return true; | |
5873 | ||
09b42213 | 5874 | case FMA_EXPR: |
5875 | case VEC_PERM_EXPR: | |
5876 | for (i = 0; i < 3; ++i) | |
2055d27a | 5877 | if (!RECUR (TREE_OPERAND (t, i), true)) |
09b42213 | 5878 | return false; |
5879 | return true; | |
5880 | ||
5881 | case COND_EXPR: | |
b0fe8b95 | 5882 | if (COND_EXPR_IS_VEC_DELETE (t)) |
5883 | { | |
5884 | if (flags & tf_error) | |
d6a08f5c | 5885 | error_at (loc, "%<delete[]%> is not a constant expression"); |
b0fe8b95 | 5886 | return false; |
5887 | } | |
5888 | /* Fall through. */ | |
5889 | case IF_STMT: | |
09b42213 | 5890 | case VEC_COND_EXPR: |
5891 | /* If the condition is a known constant, we know which of the legs we | |
5892 | care about; otherwise we only require that the condition and | |
5893 | either of the legs be potentially constant. */ | |
5894 | tmp = TREE_OPERAND (t, 0); | |
2055d27a | 5895 | if (!RECUR (tmp, rval)) |
09b42213 | 5896 | return false; |
5897 | if (!processing_template_decl) | |
5898 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
5899 | if (integer_zerop (tmp)) | |
2055d27a | 5900 | return RECUR (TREE_OPERAND (t, 2), want_rval); |
09b42213 | 5901 | else if (TREE_CODE (tmp) == INTEGER_CST) |
2055d27a | 5902 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 5903 | for (i = 1; i < 3; ++i) |
5904 | if (potential_constant_expression_1 (TREE_OPERAND (t, i), | |
7e1f8be4 | 5905 | want_rval, strict, now, tf_none)) |
09b42213 | 5906 | return true; |
5907 | if (flags & tf_error) | |
d6a08f5c | 5908 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 5909 | return false; |
5910 | ||
5911 | case VEC_INIT_EXPR: | |
5912 | if (VEC_INIT_EXPR_IS_CONSTEXPR (t)) | |
5913 | return true; | |
5914 | if (flags & tf_error) | |
5915 | { | |
d6a08f5c | 5916 | error_at (loc, "non-constant array initialization"); |
09b42213 | 5917 | diagnose_non_constexpr_vec_init (t); |
5918 | } | |
5919 | return false; | |
5920 | ||
db1ae94f | 5921 | case TYPE_DECL: |
5922 | case TAG_DEFN: | |
5923 | /* We can see these in statement-expressions. */ | |
5924 | return true; | |
5925 | ||
fd130325 | 5926 | case CLEANUP_STMT: |
d2c63826 | 5927 | case EMPTY_CLASS_EXPR: |
38ef3642 | 5928 | case PREDICT_EXPR: |
d2c63826 | 5929 | return false; |
5930 | ||
d1980671 | 5931 | case GOTO_EXPR: |
5932 | { | |
5933 | tree *target = &TREE_OPERAND (t, 0); | |
d40a1eac | 5934 | /* Gotos representing break and continue are OK. */ |
5935 | if (breaks (target) || continues (target)) | |
5936 | return true; | |
5937 | if (flags & tf_error) | |
d6a08f5c | 5938 | error_at (loc, "%<goto%> is not a constant expression"); |
d40a1eac | 5939 | return false; |
d1980671 | 5940 | } |
5941 | ||
24c6ee98 | 5942 | case ANNOTATE_EXPR: |
5943 | gcc_assert (tree_to_uhwi (TREE_OPERAND (t, 1)) == annot_expr_ivdep_kind); | |
5944 | return RECUR (TREE_OPERAND (t, 0), rval); | |
5945 | ||
09b42213 | 5946 | default: |
5947 | if (objc_is_property_ref (t)) | |
5948 | return false; | |
5949 | ||
5950 | sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t))); | |
d40a1eac | 5951 | gcc_unreachable (); |
09b42213 | 5952 | return false; |
5953 | } | |
2055d27a | 5954 | #undef RECUR |
09b42213 | 5955 | } |
5956 | ||
5957 | /* The main entry point to the above. */ | |
5958 | ||
5959 | bool | |
5960 | potential_constant_expression (tree t) | |
5961 | { | |
7e1f8be4 | 5962 | return potential_constant_expression_1 (t, false, true, false, tf_none); |
09b42213 | 5963 | } |
5964 | ||
5965 | /* As above, but require a constant rvalue. */ | |
5966 | ||
5967 | bool | |
5968 | potential_rvalue_constant_expression (tree t) | |
5969 | { | |
7e1f8be4 | 5970 | return potential_constant_expression_1 (t, true, true, false, tf_none); |
09b42213 | 5971 | } |
5972 | ||
5973 | /* Like above, but complain about non-constant expressions. */ | |
5974 | ||
5975 | bool | |
5976 | require_potential_constant_expression (tree t) | |
5977 | { | |
7e1f8be4 | 5978 | return potential_constant_expression_1 (t, false, true, false, tf_warning_or_error); |
09b42213 | 5979 | } |
5980 | ||
5981 | /* Cross product of the above. */ | |
5982 | ||
5983 | bool | |
5984 | require_potential_rvalue_constant_expression (tree t) | |
5985 | { | |
7e1f8be4 | 5986 | return potential_constant_expression_1 (t, true, true, false, tf_warning_or_error); |
5987 | } | |
5988 | ||
5989 | /* Like potential_constant_expression, but don't consider possible constexpr | |
5990 | substitution of the current function. That is, PARM_DECL qualifies under | |
5991 | potential_constant_expression, but not here. | |
5992 | ||
5993 | This is basically what you can check when any actual constant values might | |
5994 | be value-dependent. */ | |
5995 | ||
5996 | bool | |
5997 | is_constant_expression (tree t) | |
5998 | { | |
5999 | return potential_constant_expression_1 (t, false, true, true, tf_none); | |
6000 | } | |
6001 | ||
6002 | /* Like above, but complain about non-constant expressions. */ | |
6003 | ||
6004 | bool | |
6005 | require_constant_expression (tree t) | |
6006 | { | |
6007 | return potential_constant_expression_1 (t, false, true, true, | |
6008 | tf_warning_or_error); | |
6009 | } | |
6010 | ||
6011 | /* Like is_constant_expression, but allow const variables that are not allowed | |
6012 | under constexpr rules. */ | |
6013 | ||
6014 | bool | |
6015 | is_static_init_expression (tree t) | |
6016 | { | |
6017 | return potential_constant_expression_1 (t, false, false, true, tf_none); | |
09b42213 | 6018 | } |
6019 | ||
29cf24ec | 6020 | /* Returns true if T is a potential constant expression that is not |
6021 | instantiation-dependent, and therefore a candidate for constant folding even | |
6022 | in a template. */ | |
6023 | ||
6024 | bool | |
7e1f8be4 | 6025 | is_nondependent_constant_expression (tree t) |
29cf24ec | 6026 | { |
6027 | return (!type_unknown_p (t) | |
6028 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6029 | && is_constant_expression (t) |
29cf24ec | 6030 | && !instantiation_dependent_expression_p (t)); |
6031 | } | |
6032 | ||
6033 | /* Returns true if T is a potential static initializer expression that is not | |
6034 | instantiation-dependent. */ | |
6035 | ||
6036 | bool | |
7e1f8be4 | 6037 | is_nondependent_static_init_expression (tree t) |
29cf24ec | 6038 | { |
6039 | return (!type_unknown_p (t) | |
6040 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6041 | && is_static_init_expression (t) |
29cf24ec | 6042 | && !instantiation_dependent_expression_p (t)); |
6043 | } | |
6044 | ||
a050099a | 6045 | /* Finalize constexpr processing after parsing. */ |
6046 | ||
6047 | void | |
6048 | fini_constexpr (void) | |
6049 | { | |
6050 | /* The contexpr call and fundef copies tables are no longer needed. */ | |
6051 | constexpr_call_table = NULL; | |
6052 | fundef_copies_table = NULL; | |
6053 | } | |
6054 | ||
09b42213 | 6055 | #include "gt-cp-constexpr.h" |