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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 | ||
8e8f6434 | 5 | Copyright (C) 1998-2018 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 | |
e89257db | 78 | be literal. Return error_mark_node if we give an error, the |
79 | DECL otherwise. */ | |
09b42213 | 80 | |
81 | tree | |
82 | ensure_literal_type_for_constexpr_object (tree decl) | |
83 | { | |
84 | tree type = TREE_TYPE (decl); | |
85 | if (VAR_P (decl) | |
86 | && (DECL_DECLARED_CONSTEXPR_P (decl) | |
87 | || var_in_constexpr_fn (decl)) | |
88 | && !processing_template_decl) | |
89 | { | |
90 | tree stype = strip_array_types (type); | |
91 | if (CLASS_TYPE_P (stype) && !COMPLETE_TYPE_P (complete_type (stype))) | |
92 | /* Don't complain here, we'll complain about incompleteness | |
93 | when we try to initialize the variable. */; | |
94 | else if (!literal_type_p (type)) | |
95 | { | |
96 | if (DECL_DECLARED_CONSTEXPR_P (decl)) | |
e45408ff | 97 | { |
5967b28b | 98 | error ("the type %qT of %<constexpr%> variable %qD " |
99 | "is not literal", type, decl); | |
e45408ff | 100 | explain_non_literal_class (type); |
e89257db | 101 | decl = error_mark_node; |
e45408ff | 102 | } |
09b42213 | 103 | else |
9c96033c | 104 | { |
b7e4a558 | 105 | if (!is_instantiation_of_constexpr (current_function_decl)) |
e45408ff | 106 | { |
107 | error ("variable %qD of non-literal type %qT in %<constexpr%> " | |
108 | "function", decl, type); | |
109 | explain_non_literal_class (type); | |
e89257db | 110 | decl = error_mark_node; |
e45408ff | 111 | } |
9c96033c | 112 | cp_function_chain->invalid_constexpr = true; |
113 | } | |
09b42213 | 114 | } |
115 | } | |
116 | return decl; | |
117 | } | |
118 | ||
119 | /* Representation of entries in the constexpr function definition table. */ | |
120 | ||
121 | struct GTY((for_user)) constexpr_fundef { | |
122 | tree decl; | |
123 | tree body; | |
124 | }; | |
125 | ||
b594087e | 126 | struct constexpr_fundef_hasher : ggc_ptr_hash<constexpr_fundef> |
09b42213 | 127 | { |
128 | static hashval_t hash (constexpr_fundef *); | |
129 | static bool equal (constexpr_fundef *, constexpr_fundef *); | |
130 | }; | |
131 | ||
132 | /* This table holds all constexpr function definitions seen in | |
133 | the current translation unit. */ | |
134 | ||
135 | static GTY (()) hash_table<constexpr_fundef_hasher> *constexpr_fundef_table; | |
136 | ||
137 | /* Utility function used for managing the constexpr function table. | |
138 | Return true if the entries pointed to by P and Q are for the | |
139 | same constexpr function. */ | |
140 | ||
141 | inline bool | |
142 | constexpr_fundef_hasher::equal (constexpr_fundef *lhs, constexpr_fundef *rhs) | |
143 | { | |
144 | return lhs->decl == rhs->decl; | |
145 | } | |
146 | ||
147 | /* Utility function used for managing the constexpr function table. | |
148 | Return a hash value for the entry pointed to by Q. */ | |
149 | ||
150 | inline hashval_t | |
151 | constexpr_fundef_hasher::hash (constexpr_fundef *fundef) | |
152 | { | |
153 | return DECL_UID (fundef->decl); | |
154 | } | |
155 | ||
156 | /* Return a previously saved definition of function FUN. */ | |
157 | ||
158 | static constexpr_fundef * | |
159 | retrieve_constexpr_fundef (tree fun) | |
160 | { | |
161 | constexpr_fundef fundef = { NULL, NULL }; | |
162 | if (constexpr_fundef_table == NULL) | |
163 | return NULL; | |
164 | ||
165 | fundef.decl = fun; | |
166 | return constexpr_fundef_table->find (&fundef); | |
167 | } | |
168 | ||
169 | /* Check whether the parameter and return types of FUN are valid for a | |
170 | constexpr function, and complain if COMPLAIN. */ | |
171 | ||
33603066 | 172 | bool |
09b42213 | 173 | is_valid_constexpr_fn (tree fun, bool complain) |
174 | { | |
175 | bool ret = true; | |
176 | ||
7896267d | 177 | if (DECL_INHERITED_CTOR (fun) |
09b42213 | 178 | && TREE_CODE (fun) == TEMPLATE_DECL) |
179 | { | |
180 | ret = false; | |
181 | if (complain) | |
5967b28b | 182 | error ("inherited constructor %qD is not %<constexpr%>", |
7896267d | 183 | DECL_INHERITED_CTOR (fun)); |
09b42213 | 184 | } |
185 | else | |
186 | { | |
187 | for (tree parm = FUNCTION_FIRST_USER_PARM (fun); | |
188 | parm != NULL_TREE; parm = TREE_CHAIN (parm)) | |
189 | if (!literal_type_p (TREE_TYPE (parm))) | |
190 | { | |
191 | ret = false; | |
192 | if (complain) | |
193 | { | |
5967b28b | 194 | error ("invalid type for parameter %d of %<constexpr%> " |
09b42213 | 195 | "function %q+#D", DECL_PARM_INDEX (parm), fun); |
196 | explain_non_literal_class (TREE_TYPE (parm)); | |
197 | } | |
198 | } | |
199 | } | |
200 | ||
672871ce | 201 | if (LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) && cxx_dialect < cxx17) |
202 | { | |
203 | ret = false; | |
204 | if (complain) | |
205 | inform (DECL_SOURCE_LOCATION (fun), | |
5967b28b | 206 | "lambdas are implicitly %<constexpr%> only in C++17 and later"); |
672871ce | 207 | } |
208 | else if (!DECL_CONSTRUCTOR_P (fun)) | |
09b42213 | 209 | { |
210 | tree rettype = TREE_TYPE (TREE_TYPE (fun)); | |
211 | if (!literal_type_p (rettype)) | |
212 | { | |
213 | ret = false; | |
214 | if (complain) | |
215 | { | |
5967b28b | 216 | error ("invalid return type %qT of %<constexpr%> function %q+D", |
09b42213 | 217 | rettype, fun); |
218 | explain_non_literal_class (rettype); | |
219 | } | |
220 | } | |
221 | ||
d66f34cf | 222 | /* C++14 DR 1684 removed this restriction. */ |
223 | if (cxx_dialect < cxx14 | |
224 | && DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
09b42213 | 225 | && !CLASSTYPE_LITERAL_P (DECL_CONTEXT (fun))) |
226 | { | |
227 | ret = false; | |
d66f34cf | 228 | if (complain |
229 | && pedwarn (DECL_SOURCE_LOCATION (fun), OPT_Wpedantic, | |
5967b28b | 230 | "enclosing class of %<constexpr%> non-static member " |
d66f34cf | 231 | "function %q+#D is not a literal type", fun)) |
232 | explain_non_literal_class (DECL_CONTEXT (fun)); | |
09b42213 | 233 | } |
234 | } | |
235 | else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun))) | |
236 | { | |
237 | ret = false; | |
238 | if (complain) | |
239 | error ("%q#T has virtual base classes", DECL_CONTEXT (fun)); | |
240 | } | |
241 | ||
242 | return ret; | |
243 | } | |
244 | ||
245 | /* Subroutine of build_data_member_initialization. MEMBER is a COMPONENT_REF | |
246 | for a member of an anonymous aggregate, INIT is the initializer for that | |
247 | member, and VEC_OUTER is the vector of constructor elements for the class | |
248 | whose constructor we are processing. Add the initializer to the vector | |
249 | and return true to indicate success. */ | |
250 | ||
251 | static bool | |
252 | build_anon_member_initialization (tree member, tree init, | |
253 | vec<constructor_elt, va_gc> **vec_outer) | |
254 | { | |
255 | /* MEMBER presents the relevant fields from the inside out, but we need | |
256 | to build up the initializer from the outside in so that we can reuse | |
257 | previously built CONSTRUCTORs if this is, say, the second field in an | |
258 | anonymous struct. So we use a vec as a stack. */ | |
259 | auto_vec<tree, 2> fields; | |
260 | do | |
261 | { | |
262 | fields.safe_push (TREE_OPERAND (member, 1)); | |
263 | member = TREE_OPERAND (member, 0); | |
264 | } | |
265 | while (ANON_AGGR_TYPE_P (TREE_TYPE (member)) | |
266 | && TREE_CODE (member) == COMPONENT_REF); | |
267 | ||
268 | /* VEC has the constructor elements vector for the context of FIELD. | |
269 | If FIELD is an anonymous aggregate, we will push inside it. */ | |
270 | vec<constructor_elt, va_gc> **vec = vec_outer; | |
271 | tree field; | |
272 | while (field = fields.pop(), | |
273 | ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
274 | { | |
275 | tree ctor; | |
276 | /* If there is already an outer constructor entry for the anonymous | |
277 | aggregate FIELD, use it; otherwise, insert one. */ | |
278 | if (vec_safe_is_empty (*vec) | |
279 | || (*vec)->last().index != field) | |
280 | { | |
281 | ctor = build_constructor (TREE_TYPE (field), NULL); | |
282 | CONSTRUCTOR_APPEND_ELT (*vec, field, ctor); | |
283 | } | |
284 | else | |
285 | ctor = (*vec)->last().value; | |
286 | vec = &CONSTRUCTOR_ELTS (ctor); | |
287 | } | |
288 | ||
289 | /* Now we're at the innermost field, the one that isn't an anonymous | |
290 | aggregate. Add its initializer to the CONSTRUCTOR and we're done. */ | |
291 | gcc_assert (fields.is_empty()); | |
292 | CONSTRUCTOR_APPEND_ELT (*vec, field, init); | |
293 | ||
294 | return true; | |
295 | } | |
296 | ||
297 | /* Subroutine of build_constexpr_constructor_member_initializers. | |
298 | The expression tree T represents a data member initialization | |
299 | in a (constexpr) constructor definition. Build a pairing of | |
300 | the data member with its initializer, and prepend that pair | |
301 | to the existing initialization pair INITS. */ | |
302 | ||
303 | static bool | |
304 | build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec) | |
305 | { | |
306 | tree member, init; | |
307 | if (TREE_CODE (t) == CLEANUP_POINT_EXPR) | |
308 | t = TREE_OPERAND (t, 0); | |
309 | if (TREE_CODE (t) == EXPR_STMT) | |
310 | t = TREE_OPERAND (t, 0); | |
311 | if (t == error_mark_node) | |
312 | return false; | |
313 | if (TREE_CODE (t) == STATEMENT_LIST) | |
314 | { | |
315 | tree_stmt_iterator i; | |
316 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
317 | { | |
318 | if (! build_data_member_initialization (tsi_stmt (i), vec)) | |
319 | return false; | |
320 | } | |
321 | return true; | |
322 | } | |
323 | if (TREE_CODE (t) == CLEANUP_STMT) | |
324 | { | |
325 | /* We can't see a CLEANUP_STMT in a constructor for a literal class, | |
326 | but we can in a constexpr constructor for a non-literal class. Just | |
327 | ignore it; either all the initialization will be constant, in which | |
328 | case the cleanup can't run, or it can't be constexpr. | |
329 | Still recurse into CLEANUP_BODY. */ | |
330 | return build_data_member_initialization (CLEANUP_BODY (t), vec); | |
331 | } | |
332 | if (TREE_CODE (t) == CONVERT_EXPR) | |
333 | t = TREE_OPERAND (t, 0); | |
334 | if (TREE_CODE (t) == INIT_EXPR | |
9c96033c | 335 | /* vptr initialization shows up as a MODIFY_EXPR. In C++14 we only |
336 | use what this function builds for cx_check_missing_mem_inits, and | |
337 | assignment in the ctor body doesn't count. */ | |
338 | || (cxx_dialect < cxx14 && TREE_CODE (t) == MODIFY_EXPR)) | |
09b42213 | 339 | { |
340 | member = TREE_OPERAND (t, 0); | |
341 | init = break_out_target_exprs (TREE_OPERAND (t, 1)); | |
342 | } | |
343 | else if (TREE_CODE (t) == CALL_EXPR) | |
344 | { | |
9c96033c | 345 | tree fn = get_callee_fndecl (t); |
346 | if (!fn || !DECL_CONSTRUCTOR_P (fn)) | |
347 | /* We're only interested in calls to subobject constructors. */ | |
348 | return true; | |
09b42213 | 349 | member = CALL_EXPR_ARG (t, 0); |
350 | /* We don't use build_cplus_new here because it complains about | |
351 | abstract bases. Leaving the call unwrapped means that it has the | |
352 | wrong type, but cxx_eval_constant_expression doesn't care. */ | |
353 | init = break_out_target_exprs (t); | |
354 | } | |
355 | else if (TREE_CODE (t) == BIND_EXPR) | |
356 | return build_data_member_initialization (BIND_EXPR_BODY (t), vec); | |
09b42213 | 357 | else |
9c96033c | 358 | /* Don't add anything else to the CONSTRUCTOR. */ |
359 | return true; | |
09b42213 | 360 | if (INDIRECT_REF_P (member)) |
361 | member = TREE_OPERAND (member, 0); | |
362 | if (TREE_CODE (member) == NOP_EXPR) | |
363 | { | |
364 | tree op = member; | |
365 | STRIP_NOPS (op); | |
366 | if (TREE_CODE (op) == ADDR_EXPR) | |
367 | { | |
368 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
369 | (TREE_TYPE (TREE_TYPE (op)), | |
370 | TREE_TYPE (TREE_TYPE (member)))); | |
371 | /* Initializing a cv-qualified member; we need to look through | |
372 | the const_cast. */ | |
373 | member = op; | |
374 | } | |
375 | else if (op == current_class_ptr | |
376 | && (same_type_ignoring_top_level_qualifiers_p | |
377 | (TREE_TYPE (TREE_TYPE (member)), | |
378 | current_class_type))) | |
379 | /* Delegating constructor. */ | |
380 | member = op; | |
381 | else | |
382 | { | |
383 | /* This is an initializer for an empty base; keep it for now so | |
384 | we can check it in cxx_eval_bare_aggregate. */ | |
385 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (member)))); | |
386 | } | |
387 | } | |
388 | if (TREE_CODE (member) == ADDR_EXPR) | |
389 | member = TREE_OPERAND (member, 0); | |
390 | if (TREE_CODE (member) == COMPONENT_REF) | |
391 | { | |
392 | tree aggr = TREE_OPERAND (member, 0); | |
4952bc85 | 393 | if (TREE_CODE (aggr) == VAR_DECL) |
394 | /* Initializing a local variable, don't add anything. */ | |
395 | return true; | |
09b42213 | 396 | if (TREE_CODE (aggr) != COMPONENT_REF) |
397 | /* Normal member initialization. */ | |
398 | member = TREE_OPERAND (member, 1); | |
399 | else if (ANON_AGGR_TYPE_P (TREE_TYPE (aggr))) | |
400 | /* Initializing a member of an anonymous union. */ | |
401 | return build_anon_member_initialization (member, init, vec); | |
402 | else | |
403 | /* We're initializing a vtable pointer in a base. Leave it as | |
404 | COMPONENT_REF so we remember the path to get to the vfield. */ | |
405 | gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node); | |
406 | } | |
407 | ||
c678e23e | 408 | /* Value-initialization can produce multiple initializers for the |
409 | same field; use the last one. */ | |
410 | if (!vec_safe_is_empty (*vec) && (*vec)->last().index == member) | |
411 | (*vec)->last().value = init; | |
412 | else | |
413 | CONSTRUCTOR_APPEND_ELT (*vec, member, init); | |
09b42213 | 414 | return true; |
415 | } | |
416 | ||
417 | /* Subroutine of check_constexpr_ctor_body_1 and constexpr_fn_retval. | |
418 | In C++11 mode checks that the TYPE_DECLs in the BIND_EXPR_VARS of a | |
419 | BIND_EXPR conform to 7.1.5/3/4 on typedef and alias declarations. */ | |
420 | ||
421 | static bool | |
422 | check_constexpr_bind_expr_vars (tree t) | |
423 | { | |
424 | gcc_assert (TREE_CODE (t) == BIND_EXPR); | |
425 | ||
09b42213 | 426 | for (tree var = BIND_EXPR_VARS (t); var; var = DECL_CHAIN (var)) |
427 | if (TREE_CODE (var) == TYPE_DECL | |
04103c39 | 428 | && DECL_IMPLICIT_TYPEDEF_P (var) |
429 | && !LAMBDA_TYPE_P (TREE_TYPE (var))) | |
09b42213 | 430 | return false; |
431 | return true; | |
432 | } | |
433 | ||
434 | /* Subroutine of check_constexpr_ctor_body. */ | |
435 | ||
436 | static bool | |
437 | check_constexpr_ctor_body_1 (tree last, tree list) | |
438 | { | |
439 | switch (TREE_CODE (list)) | |
440 | { | |
441 | case DECL_EXPR: | |
810702a2 | 442 | if (TREE_CODE (DECL_EXPR_DECL (list)) == USING_DECL |
443 | || TREE_CODE (DECL_EXPR_DECL (list)) == TYPE_DECL) | |
09b42213 | 444 | return true; |
09b42213 | 445 | return false; |
446 | ||
447 | case CLEANUP_POINT_EXPR: | |
448 | return check_constexpr_ctor_body (last, TREE_OPERAND (list, 0), | |
449 | /*complain=*/false); | |
450 | ||
451 | case BIND_EXPR: | |
452 | if (!check_constexpr_bind_expr_vars (list) | |
453 | || !check_constexpr_ctor_body (last, BIND_EXPR_BODY (list), | |
454 | /*complain=*/false)) | |
455 | return false; | |
456 | return true; | |
457 | ||
458 | case USING_STMT: | |
459 | case STATIC_ASSERT: | |
90567983 | 460 | case DEBUG_BEGIN_STMT: |
09b42213 | 461 | return true; |
462 | ||
463 | default: | |
464 | return false; | |
465 | } | |
466 | } | |
467 | ||
468 | /* Make sure that there are no statements after LAST in the constructor | |
469 | body represented by LIST. */ | |
470 | ||
471 | bool | |
472 | check_constexpr_ctor_body (tree last, tree list, bool complain) | |
473 | { | |
9c96033c | 474 | /* C++14 doesn't require a constexpr ctor to have an empty body. */ |
475 | if (cxx_dialect >= cxx14) | |
476 | return true; | |
477 | ||
09b42213 | 478 | bool ok = true; |
479 | if (TREE_CODE (list) == STATEMENT_LIST) | |
480 | { | |
481 | tree_stmt_iterator i = tsi_last (list); | |
482 | for (; !tsi_end_p (i); tsi_prev (&i)) | |
483 | { | |
484 | tree t = tsi_stmt (i); | |
485 | if (t == last) | |
486 | break; | |
487 | if (!check_constexpr_ctor_body_1 (last, t)) | |
488 | { | |
489 | ok = false; | |
490 | break; | |
491 | } | |
492 | } | |
493 | } | |
494 | else if (list != last | |
495 | && !check_constexpr_ctor_body_1 (last, list)) | |
496 | ok = false; | |
497 | if (!ok) | |
498 | { | |
499 | if (complain) | |
5967b28b | 500 | error ("%<constexpr%> constructor does not have empty body"); |
09b42213 | 501 | DECL_DECLARED_CONSTEXPR_P (current_function_decl) = false; |
502 | } | |
503 | return ok; | |
504 | } | |
505 | ||
506 | /* V is a vector of constructor elements built up for the base and member | |
507 | initializers of a constructor for TYPE. They need to be in increasing | |
508 | offset order, which they might not be yet if TYPE has a primary base | |
509 | which is not first in the base-clause or a vptr and at least one base | |
510 | all of which are non-primary. */ | |
511 | ||
512 | static vec<constructor_elt, va_gc> * | |
513 | sort_constexpr_mem_initializers (tree type, vec<constructor_elt, va_gc> *v) | |
514 | { | |
515 | tree pri = CLASSTYPE_PRIMARY_BINFO (type); | |
516 | tree field_type; | |
517 | unsigned i; | |
518 | constructor_elt *ce; | |
519 | ||
520 | if (pri) | |
521 | field_type = BINFO_TYPE (pri); | |
522 | else if (TYPE_CONTAINS_VPTR_P (type)) | |
523 | field_type = vtbl_ptr_type_node; | |
524 | else | |
525 | return v; | |
526 | ||
527 | /* Find the element for the primary base or vptr and move it to the | |
528 | beginning of the vec. */ | |
529 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
530 | if (TREE_TYPE (ce->index) == field_type) | |
531 | break; | |
532 | ||
533 | if (i > 0 && i < vec_safe_length (v)) | |
534 | { | |
535 | vec<constructor_elt, va_gc> &vref = *v; | |
536 | constructor_elt elt = vref[i]; | |
537 | for (; i > 0; --i) | |
538 | vref[i] = vref[i-1]; | |
539 | vref[0] = elt; | |
540 | } | |
541 | ||
542 | return v; | |
543 | } | |
544 | ||
545 | /* Build compile-time evalable representations of member-initializer list | |
546 | for a constexpr constructor. */ | |
547 | ||
548 | static tree | |
549 | build_constexpr_constructor_member_initializers (tree type, tree body) | |
550 | { | |
551 | vec<constructor_elt, va_gc> *vec = NULL; | |
552 | bool ok = true; | |
816919e1 | 553 | while (true) |
554 | switch (TREE_CODE (body)) | |
555 | { | |
556 | case MUST_NOT_THROW_EXPR: | |
557 | case EH_SPEC_BLOCK: | |
558 | body = TREE_OPERAND (body, 0); | |
559 | break; | |
560 | ||
561 | case STATEMENT_LIST: | |
562 | for (tree_stmt_iterator i = tsi_start (body); | |
563 | !tsi_end_p (i); tsi_next (&i)) | |
564 | { | |
565 | body = tsi_stmt (i); | |
566 | if (TREE_CODE (body) == BIND_EXPR) | |
567 | break; | |
568 | } | |
569 | break; | |
570 | ||
571 | case BIND_EXPR: | |
572 | body = BIND_EXPR_BODY (body); | |
573 | goto found; | |
574 | ||
575 | default: | |
576 | gcc_unreachable (); | |
8a36d0ec | 577 | } |
816919e1 | 578 | found: |
09b42213 | 579 | if (TREE_CODE (body) == CLEANUP_POINT_EXPR) |
580 | { | |
581 | body = TREE_OPERAND (body, 0); | |
582 | if (TREE_CODE (body) == EXPR_STMT) | |
583 | body = TREE_OPERAND (body, 0); | |
584 | if (TREE_CODE (body) == INIT_EXPR | |
585 | && (same_type_ignoring_top_level_qualifiers_p | |
586 | (TREE_TYPE (TREE_OPERAND (body, 0)), | |
587 | current_class_type))) | |
588 | { | |
589 | /* Trivial copy. */ | |
590 | return TREE_OPERAND (body, 1); | |
591 | } | |
592 | ok = build_data_member_initialization (body, &vec); | |
593 | } | |
594 | else if (TREE_CODE (body) == STATEMENT_LIST) | |
595 | { | |
596 | tree_stmt_iterator i; | |
597 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
598 | { | |
599 | ok = build_data_member_initialization (tsi_stmt (i), &vec); | |
600 | if (!ok) | |
601 | break; | |
602 | } | |
603 | } | |
604 | else if (TREE_CODE (body) == TRY_BLOCK) | |
605 | { | |
606 | error ("body of %<constexpr%> constructor cannot be " | |
607 | "a function-try-block"); | |
608 | return error_mark_node; | |
609 | } | |
610 | else if (EXPR_P (body)) | |
611 | ok = build_data_member_initialization (body, &vec); | |
612 | else | |
613 | gcc_assert (errorcount > 0); | |
614 | if (ok) | |
615 | { | |
616 | if (vec_safe_length (vec) > 0) | |
617 | { | |
618 | /* In a delegating constructor, return the target. */ | |
619 | constructor_elt *ce = &(*vec)[0]; | |
620 | if (ce->index == current_class_ptr) | |
621 | { | |
622 | body = ce->value; | |
623 | vec_free (vec); | |
624 | return body; | |
625 | } | |
626 | } | |
627 | vec = sort_constexpr_mem_initializers (type, vec); | |
628 | return build_constructor (type, vec); | |
629 | } | |
630 | else | |
631 | return error_mark_node; | |
632 | } | |
633 | ||
2fb20ba2 | 634 | /* We have an expression tree T that represents a call, either CALL_EXPR |
635 | or AGGR_INIT_EXPR. If the call is lexically to a named function, | |
636 | retrun the _DECL for that function. */ | |
637 | ||
638 | static tree | |
639 | get_function_named_in_call (tree t) | |
640 | { | |
641 | tree fun = cp_get_callee (t); | |
642 | if (fun && TREE_CODE (fun) == ADDR_EXPR | |
643 | && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL) | |
644 | fun = TREE_OPERAND (fun, 0); | |
645 | return fun; | |
646 | } | |
647 | ||
09b42213 | 648 | /* Subroutine of register_constexpr_fundef. BODY is the body of a function |
649 | declared to be constexpr, or a sub-statement thereof. Returns the | |
650 | return value if suitable, error_mark_node for a statement not allowed in | |
651 | a constexpr function, or NULL_TREE if no return value was found. */ | |
652 | ||
653 | static tree | |
654 | constexpr_fn_retval (tree body) | |
655 | { | |
656 | switch (TREE_CODE (body)) | |
657 | { | |
658 | case STATEMENT_LIST: | |
659 | { | |
660 | tree_stmt_iterator i; | |
661 | tree expr = NULL_TREE; | |
662 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
663 | { | |
664 | tree s = constexpr_fn_retval (tsi_stmt (i)); | |
665 | if (s == error_mark_node) | |
666 | return error_mark_node; | |
667 | else if (s == NULL_TREE) | |
668 | /* Keep iterating. */; | |
669 | else if (expr) | |
670 | /* Multiple return statements. */ | |
671 | return error_mark_node; | |
672 | else | |
673 | expr = s; | |
674 | } | |
675 | return expr; | |
676 | } | |
677 | ||
678 | case RETURN_EXPR: | |
679 | return break_out_target_exprs (TREE_OPERAND (body, 0)); | |
680 | ||
681 | case DECL_EXPR: | |
394aed6a | 682 | { |
683 | tree decl = DECL_EXPR_DECL (body); | |
684 | if (TREE_CODE (decl) == USING_DECL | |
685 | /* Accept __func__, __FUNCTION__, and __PRETTY_FUNCTION__. */ | |
686 | || DECL_ARTIFICIAL (decl)) | |
687 | return NULL_TREE; | |
688 | return error_mark_node; | |
689 | } | |
09b42213 | 690 | |
691 | case CLEANUP_POINT_EXPR: | |
692 | return constexpr_fn_retval (TREE_OPERAND (body, 0)); | |
693 | ||
694 | case BIND_EXPR: | |
695 | if (!check_constexpr_bind_expr_vars (body)) | |
696 | return error_mark_node; | |
697 | return constexpr_fn_retval (BIND_EXPR_BODY (body)); | |
698 | ||
699 | case USING_STMT: | |
90567983 | 700 | case DEBUG_BEGIN_STMT: |
09b42213 | 701 | return NULL_TREE; |
702 | ||
2fb20ba2 | 703 | case CALL_EXPR: |
704 | { | |
705 | tree fun = get_function_named_in_call (body); | |
706 | if (fun != NULL_TREE | |
707 | && DECL_FUNCTION_CODE (fun) == BUILT_IN_UNREACHABLE) | |
708 | return NULL_TREE; | |
709 | } | |
710 | /* Fallthru. */ | |
711 | ||
09b42213 | 712 | default: |
713 | return error_mark_node; | |
714 | } | |
715 | } | |
716 | ||
717 | /* Subroutine of register_constexpr_fundef. BODY is the DECL_SAVED_TREE of | |
718 | FUN; do the necessary transformations to turn it into a single expression | |
719 | that we can store in the hash table. */ | |
720 | ||
721 | static tree | |
722 | massage_constexpr_body (tree fun, tree body) | |
723 | { | |
724 | if (DECL_CONSTRUCTOR_P (fun)) | |
725 | body = build_constexpr_constructor_member_initializers | |
726 | (DECL_CONTEXT (fun), body); | |
9c96033c | 727 | else if (cxx_dialect < cxx14) |
09b42213 | 728 | { |
729 | if (TREE_CODE (body) == EH_SPEC_BLOCK) | |
730 | body = EH_SPEC_STMTS (body); | |
731 | if (TREE_CODE (body) == MUST_NOT_THROW_EXPR) | |
732 | body = TREE_OPERAND (body, 0); | |
733 | body = constexpr_fn_retval (body); | |
734 | } | |
735 | return body; | |
736 | } | |
737 | ||
2f4cab3c | 738 | /* CTYPE is a type constructed from BODY. Return true if some |
739 | bases/fields are uninitialized, and complain if COMPLAIN. */ | |
09b42213 | 740 | |
741 | static bool | |
2f4cab3c | 742 | cx_check_missing_mem_inits (tree ctype, tree body, bool complain) |
09b42213 | 743 | { |
2f4cab3c | 744 | unsigned nelts = 0; |
745 | ||
746 | if (body) | |
747 | { | |
748 | if (TREE_CODE (body) != CONSTRUCTOR) | |
749 | return false; | |
750 | nelts = CONSTRUCTOR_NELTS (body); | |
751 | } | |
752 | tree field = TYPE_FIELDS (ctype); | |
09b42213 | 753 | |
754 | if (TREE_CODE (ctype) == UNION_TYPE) | |
755 | { | |
756 | if (nelts == 0 && next_initializable_field (field)) | |
757 | { | |
758 | if (complain) | |
759 | error ("%<constexpr%> constructor for union %qT must " | |
760 | "initialize exactly one non-static data member", ctype); | |
761 | return true; | |
762 | } | |
763 | return false; | |
764 | } | |
765 | ||
2f4cab3c | 766 | /* Iterate over the CONSTRUCTOR, checking any missing fields don't |
767 | need an explicit initialization. */ | |
768 | bool bad = false; | |
769 | for (unsigned i = 0; i <= nelts; ++i) | |
09b42213 | 770 | { |
2f4cab3c | 771 | tree index = NULL_TREE; |
772 | if (i < nelts) | |
09b42213 | 773 | { |
774 | index = CONSTRUCTOR_ELT (body, i)->index; | |
775 | /* Skip base and vtable inits. */ | |
776 | if (TREE_CODE (index) != FIELD_DECL | |
777 | || DECL_ARTIFICIAL (index)) | |
778 | continue; | |
779 | } | |
2f4cab3c | 780 | |
09b42213 | 781 | for (; field != index; field = DECL_CHAIN (field)) |
782 | { | |
783 | tree ftype; | |
2f4cab3c | 784 | if (TREE_CODE (field) != FIELD_DECL) |
785 | continue; | |
3cde3c29 | 786 | if (DECL_UNNAMED_BIT_FIELD (field)) |
09b42213 | 787 | continue; |
2f4cab3c | 788 | if (DECL_ARTIFICIAL (field)) |
789 | continue; | |
790 | if (ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
791 | { | |
792 | /* Recurse to check the anonummous aggregate member. */ | |
793 | bad |= cx_check_missing_mem_inits | |
794 | (TREE_TYPE (field), NULL_TREE, complain); | |
795 | if (bad && !complain) | |
796 | return true; | |
797 | continue; | |
798 | } | |
09b42213 | 799 | ftype = strip_array_types (TREE_TYPE (field)); |
800 | if (type_has_constexpr_default_constructor (ftype)) | |
801 | { | |
802 | /* It's OK to skip a member with a trivial constexpr ctor. | |
803 | A constexpr ctor that isn't trivial should have been | |
804 | added in by now. */ | |
805 | gcc_checking_assert (!TYPE_HAS_COMPLEX_DFLT (ftype) | |
806 | || errorcount != 0); | |
807 | continue; | |
808 | } | |
809 | if (!complain) | |
810 | return true; | |
859e2c29 | 811 | error ("member %qD must be initialized by mem-initializer " |
812 | "in %<constexpr%> constructor", field); | |
813 | inform (DECL_SOURCE_LOCATION (field), "declared here"); | |
09b42213 | 814 | bad = true; |
815 | } | |
816 | if (field == NULL_TREE) | |
817 | break; | |
2f4cab3c | 818 | |
819 | if (ANON_AGGR_TYPE_P (TREE_TYPE (index))) | |
820 | { | |
821 | /* Check the anonymous aggregate initializer is valid. */ | |
822 | bad |= cx_check_missing_mem_inits | |
823 | (TREE_TYPE (index), CONSTRUCTOR_ELT (body, i)->value, complain); | |
824 | if (bad && !complain) | |
825 | return true; | |
826 | } | |
09b42213 | 827 | field = DECL_CHAIN (field); |
828 | } | |
829 | ||
830 | return bad; | |
831 | } | |
832 | ||
833 | /* We are processing the definition of the constexpr function FUN. | |
834 | Check that its BODY fulfills the propriate requirements and | |
835 | enter it in the constexpr function definition table. | |
836 | For constructor BODY is actually the TREE_LIST of the | |
837 | member-initializer list. */ | |
838 | ||
839 | tree | |
840 | register_constexpr_fundef (tree fun, tree body) | |
841 | { | |
842 | constexpr_fundef entry; | |
843 | constexpr_fundef **slot; | |
844 | ||
845 | if (!is_valid_constexpr_fn (fun, !DECL_GENERATED_P (fun))) | |
846 | return NULL; | |
847 | ||
6a385150 | 848 | tree massaged = massage_constexpr_body (fun, body); |
849 | if (massaged == NULL_TREE || massaged == error_mark_node) | |
09b42213 | 850 | { |
851 | if (!DECL_CONSTRUCTOR_P (fun)) | |
5967b28b | 852 | error ("body of %<constexpr%> function %qD not a return-statement", |
853 | fun); | |
09b42213 | 854 | return NULL; |
855 | } | |
856 | ||
6a385150 | 857 | if (!potential_rvalue_constant_expression (massaged)) |
09b42213 | 858 | { |
859 | if (!DECL_GENERATED_P (fun)) | |
6a385150 | 860 | require_potential_rvalue_constant_expression (massaged); |
09b42213 | 861 | return NULL; |
862 | } | |
863 | ||
864 | if (DECL_CONSTRUCTOR_P (fun) | |
2f4cab3c | 865 | && cx_check_missing_mem_inits (DECL_CONTEXT (fun), |
866 | massaged, !DECL_GENERATED_P (fun))) | |
09b42213 | 867 | return NULL; |
868 | ||
869 | /* Create the constexpr function table if necessary. */ | |
870 | if (constexpr_fundef_table == NULL) | |
871 | constexpr_fundef_table | |
872 | = hash_table<constexpr_fundef_hasher>::create_ggc (101); | |
873 | ||
874 | entry.decl = fun; | |
875 | entry.body = body; | |
876 | slot = constexpr_fundef_table->find_slot (&entry, INSERT); | |
877 | ||
878 | gcc_assert (*slot == NULL); | |
879 | *slot = ggc_alloc<constexpr_fundef> (); | |
880 | **slot = entry; | |
881 | ||
882 | return fun; | |
883 | } | |
884 | ||
885 | /* FUN is a non-constexpr function called in a context that requires a | |
886 | constant expression. If it comes from a constexpr template, explain why | |
887 | the instantiation isn't constexpr. */ | |
888 | ||
889 | void | |
890 | explain_invalid_constexpr_fn (tree fun) | |
891 | { | |
892 | static hash_set<tree> *diagnosed; | |
893 | tree body; | |
894 | location_t save_loc; | |
33603066 | 895 | /* Only diagnose defaulted functions, lambdas, or instantiations. */ |
09b42213 | 896 | if (!DECL_DEFAULTED_FN (fun) |
33603066 | 897 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) |
09b42213 | 898 | && !is_instantiation_of_constexpr (fun)) |
899 | return; | |
900 | if (diagnosed == NULL) | |
901 | diagnosed = new hash_set<tree>; | |
902 | if (diagnosed->add (fun)) | |
903 | /* Already explained. */ | |
904 | return; | |
905 | ||
906 | save_loc = input_location; | |
33603066 | 907 | if (!lambda_static_thunk_p (fun)) |
908 | { | |
909 | /* Diagnostics should completely ignore the static thunk, so leave | |
910 | input_location set to our caller's location. */ | |
911 | input_location = DECL_SOURCE_LOCATION (fun); | |
912 | inform (input_location, | |
5967b28b | 913 | "%qD is not usable as a %<constexpr%> function because:", fun); |
33603066 | 914 | } |
09b42213 | 915 | /* First check the declaration. */ |
916 | if (is_valid_constexpr_fn (fun, true)) | |
917 | { | |
918 | /* Then if it's OK, the body. */ | |
33603066 | 919 | if (!DECL_DECLARED_CONSTEXPR_P (fun) |
920 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun))) | |
09b42213 | 921 | explain_implicit_non_constexpr (fun); |
922 | else | |
923 | { | |
924 | body = massage_constexpr_body (fun, DECL_SAVED_TREE (fun)); | |
925 | require_potential_rvalue_constant_expression (body); | |
926 | if (DECL_CONSTRUCTOR_P (fun)) | |
2f4cab3c | 927 | cx_check_missing_mem_inits (DECL_CONTEXT (fun), body, true); |
09b42213 | 928 | } |
929 | } | |
930 | input_location = save_loc; | |
931 | } | |
932 | ||
933 | /* Objects of this type represent calls to constexpr functions | |
934 | along with the bindings of parameters to their arguments, for | |
935 | the purpose of compile time evaluation. */ | |
936 | ||
937 | struct GTY((for_user)) constexpr_call { | |
938 | /* Description of the constexpr function definition. */ | |
939 | constexpr_fundef *fundef; | |
940 | /* Parameter bindings environment. A TREE_LIST where each TREE_PURPOSE | |
941 | is a parameter _DECL and the TREE_VALUE is the value of the parameter. | |
942 | Note: This arrangement is made to accommodate the use of | |
943 | iterative_hash_template_arg (see pt.c). If you change this | |
944 | representation, also change the hash calculation in | |
945 | cxx_eval_call_expression. */ | |
946 | tree bindings; | |
947 | /* Result of the call. | |
948 | NULL means the call is being evaluated. | |
949 | error_mark_node means that the evaluation was erroneous; | |
950 | otherwise, the actuall value of the call. */ | |
951 | tree result; | |
952 | /* The hash of this call; we remember it here to avoid having to | |
953 | recalculate it when expanding the hash table. */ | |
954 | hashval_t hash; | |
955 | }; | |
956 | ||
b594087e | 957 | struct constexpr_call_hasher : ggc_ptr_hash<constexpr_call> |
09b42213 | 958 | { |
959 | static hashval_t hash (constexpr_call *); | |
960 | static bool equal (constexpr_call *, constexpr_call *); | |
cf72f34d | 961 | }; |
962 | ||
2a2770c6 | 963 | enum constexpr_switch_state { |
964 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
965 | and default: label for that switch has not been seen yet. */ | |
966 | css_default_not_seen, | |
967 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
968 | and default: label for that switch has been seen already. */ | |
969 | css_default_seen, | |
970 | /* Used when processing a switch for the second time by | |
971 | cxx_eval_switch_expr, where default: label should match. */ | |
972 | css_default_processing | |
973 | }; | |
974 | ||
cf72f34d | 975 | /* The constexpr expansion context. CALL is the current function |
976 | expansion, CTOR is the current aggregate initializer, OBJECT is the | |
977 | object being initialized by CTOR, either a VAR_DECL or a _REF. VALUES | |
978 | is a map of values of variables initialized within the expression. */ | |
979 | ||
980 | struct constexpr_ctx { | |
f9885b8a | 981 | /* The innermost call we're evaluating. */ |
cf72f34d | 982 | constexpr_call *call; |
f9885b8a | 983 | /* Values for any temporaries or local variables within the |
984 | constant-expression. */ | |
cf72f34d | 985 | hash_map<tree,tree> *values; |
2631cb67 | 986 | /* SAVE_EXPRs that we've seen within the current LOOP_EXPR. NULL if we |
987 | aren't inside a loop. */ | |
988 | hash_set<tree> *save_exprs; | |
f9885b8a | 989 | /* The CONSTRUCTOR we're currently building up for an aggregate |
990 | initializer. */ | |
cf72f34d | 991 | tree ctor; |
f9885b8a | 992 | /* The object we're building the CONSTRUCTOR for. */ |
cf72f34d | 993 | tree object; |
2a2770c6 | 994 | /* If inside SWITCH_EXPR. */ |
995 | constexpr_switch_state *css_state; | |
f9885b8a | 996 | /* Whether we should error on a non-constant expression or fail quietly. */ |
f83e6885 | 997 | bool quiet; |
f9885b8a | 998 | /* Whether we are strictly conforming to constant expression rules or |
999 | trying harder to get a constant value. */ | |
2055d27a | 1000 | bool strict; |
cf72f34d | 1001 | }; |
09b42213 | 1002 | |
1003 | /* A table of all constexpr calls that have been evaluated by the | |
1004 | compiler in this translation unit. */ | |
1005 | ||
a050099a | 1006 | static GTY (()) hash_table<constexpr_call_hasher> *constexpr_call_table; |
09b42213 | 1007 | |
cf72f34d | 1008 | static tree cxx_eval_constant_expression (const constexpr_ctx *, tree, |
b2a43197 | 1009 | bool, bool *, bool *, tree * = NULL); |
09b42213 | 1010 | |
1011 | /* Compute a hash value for a constexpr call representation. */ | |
1012 | ||
1013 | inline hashval_t | |
1014 | constexpr_call_hasher::hash (constexpr_call *info) | |
1015 | { | |
1016 | return info->hash; | |
1017 | } | |
1018 | ||
1019 | /* Return true if the objects pointed to by P and Q represent calls | |
1020 | to the same constexpr function with the same arguments. | |
1021 | Otherwise, return false. */ | |
1022 | ||
1023 | bool | |
1024 | constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs) | |
1025 | { | |
1026 | tree lhs_bindings; | |
1027 | tree rhs_bindings; | |
1028 | if (lhs == rhs) | |
1029 | return 1; | |
1030 | if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef)) | |
1031 | return 0; | |
1032 | lhs_bindings = lhs->bindings; | |
1033 | rhs_bindings = rhs->bindings; | |
1034 | while (lhs_bindings != NULL && rhs_bindings != NULL) | |
1035 | { | |
1036 | tree lhs_arg = TREE_VALUE (lhs_bindings); | |
1037 | tree rhs_arg = TREE_VALUE (rhs_bindings); | |
1038 | gcc_assert (TREE_TYPE (lhs_arg) == TREE_TYPE (rhs_arg)); | |
1039 | if (!cp_tree_equal (lhs_arg, rhs_arg)) | |
1040 | return 0; | |
1041 | lhs_bindings = TREE_CHAIN (lhs_bindings); | |
1042 | rhs_bindings = TREE_CHAIN (rhs_bindings); | |
1043 | } | |
1044 | return lhs_bindings == rhs_bindings; | |
1045 | } | |
1046 | ||
1047 | /* Initialize the constexpr call table, if needed. */ | |
1048 | ||
1049 | static void | |
1050 | maybe_initialize_constexpr_call_table (void) | |
1051 | { | |
1052 | if (constexpr_call_table == NULL) | |
1053 | constexpr_call_table = hash_table<constexpr_call_hasher>::create_ggc (101); | |
1054 | } | |
1055 | ||
4f7ebe46 | 1056 | /* During constexpr CALL_EXPR evaluation, to avoid issues with sharing when |
1057 | a function happens to get called recursively, we unshare the callee | |
1058 | function's body and evaluate this unshared copy instead of evaluating the | |
1059 | original body. | |
1060 | ||
1061 | FUNDEF_COPIES_TABLE is a per-function freelist of these unshared function | |
1062 | copies. The underlying data structure of FUNDEF_COPIES_TABLE is a hash_map | |
a050099a | 1063 | that's keyed off of the original FUNCTION_DECL and whose value is a |
1064 | TREE_LIST of this function's unused copies awaiting reuse. | |
4f7ebe46 | 1065 | |
a050099a | 1066 | This is not GC-deletable to avoid GC affecting UID generation. */ |
4f7ebe46 | 1067 | |
a050099a | 1068 | static GTY(()) hash_map<tree, tree> *fundef_copies_table; |
4f7ebe46 | 1069 | |
1070 | /* Initialize FUNDEF_COPIES_TABLE if it's not initialized. */ | |
1071 | ||
1072 | static void | |
1073 | maybe_initialize_fundef_copies_table () | |
1074 | { | |
a050099a | 1075 | if (fundef_copies_table == NULL) |
1076 | fundef_copies_table = hash_map<tree,tree>::create_ggc (101); | |
4f7ebe46 | 1077 | } |
1078 | ||
1079 | /* Reuse a copy or create a new unshared copy of the function FUN. | |
886d5463 | 1080 | Return this copy. We use a TREE_LIST whose PURPOSE is body, VALUE |
1081 | is parms, TYPE is result. */ | |
4f7ebe46 | 1082 | |
a050099a | 1083 | static tree |
4f7ebe46 | 1084 | get_fundef_copy (tree fun) |
1085 | { | |
1086 | maybe_initialize_fundef_copies_table (); | |
1087 | ||
a050099a | 1088 | tree copy; |
886d5463 | 1089 | bool existed; |
1090 | tree *slot = &fundef_copies_table->get_or_insert (fun, &existed); | |
1091 | ||
1092 | if (!existed) | |
4f7ebe46 | 1093 | { |
886d5463 | 1094 | /* There is no cached function available, or in use. We can use |
1095 | the function directly. That the slot is now created records | |
1096 | that this function is now in use. */ | |
1097 | copy = build_tree_list (DECL_SAVED_TREE (fun), DECL_ARGUMENTS (fun)); | |
1098 | TREE_TYPE (copy) = DECL_RESULT (fun); | |
1099 | } | |
1100 | else if (*slot == NULL_TREE) | |
1101 | { | |
1102 | /* We've already used the function itself, so make a copy. */ | |
a050099a | 1103 | copy = build_tree_list (NULL, NULL); |
a050099a | 1104 | TREE_PURPOSE (copy) = copy_fn (fun, TREE_VALUE (copy), TREE_TYPE (copy)); |
4f7ebe46 | 1105 | } |
1106 | else | |
1107 | { | |
886d5463 | 1108 | /* We have a cached function available. */ |
4f7ebe46 | 1109 | copy = *slot; |
a050099a | 1110 | *slot = TREE_CHAIN (copy); |
4f7ebe46 | 1111 | } |
1112 | ||
1113 | return copy; | |
1114 | } | |
1115 | ||
886d5463 | 1116 | /* Save the copy COPY of function FUN for later reuse by |
1117 | get_fundef_copy(). By construction, there will always be an entry | |
1118 | to find. */ | |
4f7ebe46 | 1119 | |
1120 | static void | |
a050099a | 1121 | save_fundef_copy (tree fun, tree copy) |
4f7ebe46 | 1122 | { |
886d5463 | 1123 | tree *slot = fundef_copies_table->get (fun); |
a050099a | 1124 | TREE_CHAIN (copy) = *slot; |
4f7ebe46 | 1125 | *slot = copy; |
1126 | } | |
1127 | ||
09b42213 | 1128 | /* We have an expression tree T that represents a call, either CALL_EXPR |
1129 | or AGGR_INIT_EXPR. Return the Nth argument. */ | |
1130 | ||
1131 | static inline tree | |
1132 | get_nth_callarg (tree t, int n) | |
1133 | { | |
1134 | switch (TREE_CODE (t)) | |
1135 | { | |
1136 | case CALL_EXPR: | |
1137 | return CALL_EXPR_ARG (t, n); | |
1138 | ||
1139 | case AGGR_INIT_EXPR: | |
1140 | return AGGR_INIT_EXPR_ARG (t, n); | |
1141 | ||
1142 | default: | |
1143 | gcc_unreachable (); | |
1144 | return NULL; | |
1145 | } | |
1146 | } | |
1147 | ||
09b42213 | 1148 | /* Attempt to evaluate T which represents a call to a builtin function. |
1149 | We assume here that all builtin functions evaluate to scalar types | |
1150 | represented by _CST nodes. */ | |
1151 | ||
1152 | static tree | |
f1c6af10 | 1153 | cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, |
1227ba74 | 1154 | bool lval, |
09b42213 | 1155 | bool *non_constant_p, bool *overflow_p) |
1156 | { | |
1157 | const int nargs = call_expr_nargs (t); | |
1158 | tree *args = (tree *) alloca (nargs * sizeof (tree)); | |
1159 | tree new_call; | |
1160 | int i; | |
f1c6af10 | 1161 | |
1162 | /* Don't fold __builtin_constant_p within a constexpr function. */ | |
efe6a40a | 1163 | bool bi_const_p = (DECL_FUNCTION_CODE (fun) == BUILT_IN_CONSTANT_P); |
1164 | ||
1165 | if (bi_const_p | |
f1c6af10 | 1166 | && current_function_decl |
1167 | && DECL_DECLARED_CONSTEXPR_P (current_function_decl)) | |
09b42213 | 1168 | { |
f1c6af10 | 1169 | *non_constant_p = true; |
1170 | return t; | |
09b42213 | 1171 | } |
f1c6af10 | 1172 | |
1173 | /* Be permissive for arguments to built-ins; __builtin_constant_p should | |
1174 | return constant false for a non-constant argument. */ | |
1175 | constexpr_ctx new_ctx = *ctx; | |
1176 | new_ctx.quiet = true; | |
1177 | bool dummy1 = false, dummy2 = false; | |
1178 | for (i = 0; i < nargs; ++i) | |
efe6a40a | 1179 | { |
1180 | args[i] = cxx_eval_constant_expression (&new_ctx, CALL_EXPR_ARG (t, i), | |
051eb924 | 1181 | false, &dummy1, &dummy2); |
efe6a40a | 1182 | if (bi_const_p) |
1183 | /* For __built_in_constant_p, fold all expressions with constant values | |
1184 | even if they aren't C++ constant-expressions. */ | |
1185 | args[i] = cp_fully_fold (args[i]); | |
1186 | } | |
f1c6af10 | 1187 | |
1188 | bool save_ffbcp = force_folding_builtin_constant_p; | |
1189 | force_folding_builtin_constant_p = true; | |
051eb924 | 1190 | new_call = fold_builtin_call_array (EXPR_LOCATION (t), TREE_TYPE (t), |
1191 | CALL_EXPR_FN (t), nargs, args); | |
f1c6af10 | 1192 | force_folding_builtin_constant_p = save_ffbcp; |
051eb924 | 1193 | if (new_call == NULL) |
1194 | { | |
1195 | if (!*non_constant_p && !ctx->quiet) | |
1196 | { | |
2fb20ba2 | 1197 | /* Do not allow__builtin_unreachable in constexpr function. |
1198 | The __builtin_unreachable call with BUILTINS_LOCATION | |
1199 | comes from cp_maybe_instrument_return. */ | |
1200 | if (DECL_FUNCTION_CODE (fun) == BUILT_IN_UNREACHABLE | |
1201 | && EXPR_LOCATION (t) == BUILTINS_LOCATION) | |
5967b28b | 1202 | error ("%<constexpr%> call flows off the end of the function"); |
2fb20ba2 | 1203 | else |
1204 | { | |
1205 | new_call = build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t), | |
1206 | CALL_EXPR_FN (t), nargs, args); | |
1207 | error ("%q+E is not a constant expression", new_call); | |
1208 | } | |
051eb924 | 1209 | } |
1210 | *non_constant_p = true; | |
1211 | return t; | |
1212 | } | |
1213 | ||
7e1f8be4 | 1214 | if (!is_constant_expression (new_call)) |
051eb924 | 1215 | { |
1216 | if (!*non_constant_p && !ctx->quiet) | |
1217 | error ("%q+E is not a constant expression", new_call); | |
1218 | *non_constant_p = true; | |
1219 | return t; | |
1220 | } | |
1221 | ||
1222 | return cxx_eval_constant_expression (&new_ctx, new_call, lval, | |
1223 | non_constant_p, overflow_p); | |
09b42213 | 1224 | } |
1225 | ||
1226 | /* TEMP is the constant value of a temporary object of type TYPE. Adjust | |
1227 | the type of the value to match. */ | |
1228 | ||
1229 | static tree | |
1230 | adjust_temp_type (tree type, tree temp) | |
1231 | { | |
1232 | if (TREE_TYPE (temp) == type) | |
1233 | return temp; | |
1234 | /* Avoid wrapping an aggregate value in a NOP_EXPR. */ | |
1235 | if (TREE_CODE (temp) == CONSTRUCTOR) | |
1236 | return build_constructor (type, CONSTRUCTOR_ELTS (temp)); | |
1237 | gcc_assert (scalarish_type_p (type)); | |
1238 | return cp_fold_convert (type, temp); | |
1239 | } | |
1240 | ||
e283bb4f | 1241 | /* Callback for walk_tree used by unshare_constructor. */ |
1242 | ||
1243 | static tree | |
1244 | find_constructor (tree *tp, int *walk_subtrees, void *) | |
1245 | { | |
1246 | if (TYPE_P (*tp)) | |
1247 | *walk_subtrees = 0; | |
1248 | if (TREE_CODE (*tp) == CONSTRUCTOR) | |
1249 | return *tp; | |
1250 | return NULL_TREE; | |
1251 | } | |
1252 | ||
1253 | /* If T is a CONSTRUCTOR or an expression that has a CONSTRUCTOR node as a | |
1254 | subexpression, return an unshared copy of T. Otherwise return T. */ | |
1255 | ||
1256 | static tree | |
1257 | unshare_constructor (tree t) | |
1258 | { | |
1259 | tree ctor = walk_tree (&t, find_constructor, NULL, NULL); | |
1260 | if (ctor != NULL_TREE) | |
1261 | return unshare_expr (t); | |
1262 | return t; | |
1263 | } | |
1264 | ||
09b42213 | 1265 | /* Subroutine of cxx_eval_call_expression. |
1266 | We are processing a call expression (either CALL_EXPR or | |
cf72f34d | 1267 | AGGR_INIT_EXPR) in the context of CTX. Evaluate |
09b42213 | 1268 | all arguments and bind their values to correspondings |
1269 | parameters, making up the NEW_CALL context. */ | |
1270 | ||
1271 | static void | |
cf72f34d | 1272 | cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, |
09b42213 | 1273 | constexpr_call *new_call, |
c8f6aeb1 | 1274 | bool *non_constant_p, bool *overflow_p, |
1275 | bool *non_constant_args) | |
09b42213 | 1276 | { |
1277 | const int nargs = call_expr_nargs (t); | |
1278 | tree fun = new_call->fundef->decl; | |
1279 | tree parms = DECL_ARGUMENTS (fun); | |
1280 | int i; | |
9c96033c | 1281 | tree *p = &new_call->bindings; |
09b42213 | 1282 | for (i = 0; i < nargs; ++i) |
1283 | { | |
1284 | tree x, arg; | |
1285 | tree type = parms ? TREE_TYPE (parms) : void_type_node; | |
09b42213 | 1286 | x = get_nth_callarg (t, i); |
cf72f34d | 1287 | /* For member function, the first argument is a pointer to the implied |
1288 | object. For a constructor, it might still be a dummy object, in | |
9c96033c | 1289 | which case we get the real argument from ctx. */ |
cf72f34d | 1290 | if (i == 0 && DECL_CONSTRUCTOR_P (fun) |
1291 | && is_dummy_object (x)) | |
1292 | { | |
1293 | x = ctx->object; | |
c017458d | 1294 | x = build_address (x); |
cf72f34d | 1295 | } |
2e1c71c2 | 1296 | arg = cxx_eval_constant_expression (ctx, x, /*lval=*/false, |
b2a43197 | 1297 | non_constant_p, overflow_p); |
09b42213 | 1298 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 1299 | if (*non_constant_p && ctx->quiet) |
09b42213 | 1300 | return; |
1301 | /* Just discard ellipsis args after checking their constantitude. */ | |
1302 | if (!parms) | |
1303 | continue; | |
2ba934c7 | 1304 | |
1305 | if (!*non_constant_p) | |
1306 | { | |
1307 | /* Make sure the binding has the same type as the parm. But | |
1308 | only for constant args. */ | |
1309 | if (TREE_CODE (type) != REFERENCE_TYPE) | |
1310 | arg = adjust_temp_type (type, arg); | |
1311 | if (!TREE_CONSTANT (arg)) | |
1312 | *non_constant_args = true; | |
1313 | *p = build_tree_list (parms, arg); | |
1314 | p = &TREE_CHAIN (*p); | |
1315 | } | |
09b42213 | 1316 | parms = TREE_CHAIN (parms); |
1317 | } | |
1318 | } | |
1319 | ||
1320 | /* Variables and functions to manage constexpr call expansion context. | |
1321 | These do not need to be marked for PCH or GC. */ | |
1322 | ||
1323 | /* FIXME remember and print actual constant arguments. */ | |
16fb756f | 1324 | static vec<tree> call_stack; |
09b42213 | 1325 | static int call_stack_tick; |
1326 | static int last_cx_error_tick; | |
1327 | ||
1328 | static bool | |
1329 | push_cx_call_context (tree call) | |
1330 | { | |
1331 | ++call_stack_tick; | |
1332 | if (!EXPR_HAS_LOCATION (call)) | |
1333 | SET_EXPR_LOCATION (call, input_location); | |
1334 | call_stack.safe_push (call); | |
1335 | if (call_stack.length () > (unsigned) max_constexpr_depth) | |
1336 | return false; | |
1337 | return true; | |
1338 | } | |
1339 | ||
1340 | static void | |
1341 | pop_cx_call_context (void) | |
1342 | { | |
1343 | ++call_stack_tick; | |
1344 | call_stack.pop (); | |
1345 | } | |
1346 | ||
1347 | vec<tree> | |
1348 | cx_error_context (void) | |
1349 | { | |
1350 | vec<tree> r = vNULL; | |
1351 | if (call_stack_tick != last_cx_error_tick | |
1352 | && !call_stack.is_empty ()) | |
1353 | r = call_stack; | |
1354 | last_cx_error_tick = call_stack_tick; | |
1355 | return r; | |
1356 | } | |
1357 | ||
732905bb | 1358 | /* Evaluate a call T to a GCC internal function when possible and return |
1359 | the evaluated result or, under the control of CTX, give an error, set | |
1360 | NON_CONSTANT_P, and return the unevaluated call T otherwise. */ | |
1361 | ||
1362 | static tree | |
1363 | cxx_eval_internal_function (const constexpr_ctx *ctx, tree t, | |
1364 | bool lval, | |
1365 | bool *non_constant_p, bool *overflow_p) | |
1366 | { | |
1367 | enum tree_code opcode = ERROR_MARK; | |
1368 | ||
1369 | switch (CALL_EXPR_IFN (t)) | |
1370 | { | |
1371 | case IFN_UBSAN_NULL: | |
1372 | case IFN_UBSAN_BOUNDS: | |
1373 | case IFN_UBSAN_VPTR: | |
3c77f69c | 1374 | case IFN_FALLTHROUGH: |
732905bb | 1375 | return void_node; |
1376 | ||
1377 | case IFN_ADD_OVERFLOW: | |
1378 | opcode = PLUS_EXPR; | |
1379 | break; | |
1380 | case IFN_SUB_OVERFLOW: | |
1381 | opcode = MINUS_EXPR; | |
1382 | break; | |
1383 | case IFN_MUL_OVERFLOW: | |
1384 | opcode = MULT_EXPR; | |
1385 | break; | |
1386 | ||
6e1b2ffb | 1387 | case IFN_LAUNDER: |
1388 | return cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), | |
1389 | false, non_constant_p, overflow_p); | |
1390 | ||
732905bb | 1391 | default: |
1392 | if (!ctx->quiet) | |
1393 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
1394 | "call to internal function %qE", t); | |
1395 | *non_constant_p = true; | |
1396 | return t; | |
1397 | } | |
1398 | ||
1399 | /* Evaluate constant arguments using OPCODE and return a complex | |
1400 | number containing the result and the overflow bit. */ | |
1401 | tree arg0 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), lval, | |
1402 | non_constant_p, overflow_p); | |
1403 | tree arg1 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 1), lval, | |
1404 | non_constant_p, overflow_p); | |
1405 | ||
1406 | if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) | |
1407 | { | |
1408 | location_t loc = EXPR_LOC_OR_LOC (t, input_location); | |
1409 | tree type = TREE_TYPE (TREE_TYPE (t)); | |
1410 | tree result = fold_binary_loc (loc, opcode, type, | |
1411 | fold_convert_loc (loc, type, arg0), | |
1412 | fold_convert_loc (loc, type, arg1)); | |
1413 | tree ovf | |
1414 | = build_int_cst (type, arith_overflowed_p (opcode, type, arg0, arg1)); | |
1415 | /* Reset TREE_OVERFLOW to avoid warnings for the overflow. */ | |
1416 | if (TREE_OVERFLOW (result)) | |
1417 | TREE_OVERFLOW (result) = 0; | |
1418 | ||
1419 | return build_complex (TREE_TYPE (t), result, ovf); | |
1420 | } | |
1421 | ||
1422 | *non_constant_p = true; | |
1423 | return t; | |
1424 | } | |
1425 | ||
79cdb4f5 | 1426 | /* Clean CONSTRUCTOR_NO_IMPLICIT_ZERO from CTOR and its sub-aggregates. */ |
1427 | ||
1428 | static void | |
1429 | clear_no_implicit_zero (tree ctor) | |
1430 | { | |
1431 | if (CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor)) | |
1432 | { | |
1433 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor) = false; | |
1434 | tree elt; unsigned HOST_WIDE_INT idx; | |
1435 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (ctor), idx, elt) | |
1436 | if (TREE_CODE (elt) == CONSTRUCTOR) | |
1437 | clear_no_implicit_zero (elt); | |
1438 | } | |
1439 | } | |
1440 | ||
09b42213 | 1441 | /* Subroutine of cxx_eval_constant_expression. |
1442 | Evaluate the call expression tree T in the context of OLD_CALL expression | |
1443 | evaluation. */ | |
1444 | ||
1445 | static tree | |
cf72f34d | 1446 | cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1447 | bool lval, |
09b42213 | 1448 | bool *non_constant_p, bool *overflow_p) |
1449 | { | |
1450 | location_t loc = EXPR_LOC_OR_LOC (t, input_location); | |
1451 | tree fun = get_function_named_in_call (t); | |
09b42213 | 1452 | constexpr_call new_call = { NULL, NULL, NULL, 0 }; |
09b42213 | 1453 | bool depth_ok; |
1454 | ||
6b71bdb4 | 1455 | if (fun == NULL_TREE) |
732905bb | 1456 | return cxx_eval_internal_function (ctx, t, lval, |
1457 | non_constant_p, overflow_p); | |
6b71bdb4 | 1458 | |
09b42213 | 1459 | if (TREE_CODE (fun) != FUNCTION_DECL) |
1460 | { | |
1461 | /* Might be a constexpr function pointer. */ | |
f83e6885 | 1462 | fun = cxx_eval_constant_expression (ctx, fun, |
1227ba74 | 1463 | /*lval*/false, non_constant_p, |
b2a43197 | 1464 | overflow_p); |
09b42213 | 1465 | STRIP_NOPS (fun); |
1466 | if (TREE_CODE (fun) == ADDR_EXPR) | |
1467 | fun = TREE_OPERAND (fun, 0); | |
1468 | } | |
1469 | if (TREE_CODE (fun) != FUNCTION_DECL) | |
1470 | { | |
f83e6885 | 1471 | if (!ctx->quiet && !*non_constant_p) |
5967b28b | 1472 | error_at (loc, "expression %qE does not designate a %<constexpr%> " |
09b42213 | 1473 | "function", fun); |
1474 | *non_constant_p = true; | |
1475 | return t; | |
1476 | } | |
1477 | if (DECL_CLONED_FUNCTION_P (fun)) | |
1478 | fun = DECL_CLONED_FUNCTION (fun); | |
6b71bdb4 | 1479 | |
1480 | if (is_ubsan_builtin_p (fun)) | |
1481 | return void_node; | |
1482 | ||
09b42213 | 1483 | if (is_builtin_fn (fun)) |
f1c6af10 | 1484 | return cxx_eval_builtin_function_call (ctx, t, fun, |
1227ba74 | 1485 | lval, non_constant_p, overflow_p); |
09b42213 | 1486 | if (!DECL_DECLARED_CONSTEXPR_P (fun)) |
1487 | { | |
f83e6885 | 1488 | if (!ctx->quiet) |
09b42213 | 1489 | { |
1dcd84cf | 1490 | if (!lambda_static_thunk_p (fun)) |
5967b28b | 1491 | error_at (loc, "call to non-%<constexpr%> function %qD", fun); |
09b42213 | 1492 | explain_invalid_constexpr_fn (fun); |
1493 | } | |
1494 | *non_constant_p = true; | |
1495 | return t; | |
1496 | } | |
1497 | ||
9ebe2ea3 | 1498 | constexpr_ctx new_ctx = *ctx; |
1499 | if (DECL_CONSTRUCTOR_P (fun) && !ctx->object | |
1500 | && TREE_CODE (t) == AGGR_INIT_EXPR) | |
1501 | { | |
1502 | /* We want to have an initialization target for an AGGR_INIT_EXPR. | |
1503 | If we don't already have one in CTX, use the AGGR_INIT_EXPR_SLOT. */ | |
1504 | new_ctx.object = AGGR_INIT_EXPR_SLOT (t); | |
1505 | tree ctor = new_ctx.ctor = build_constructor (DECL_CONTEXT (fun), NULL); | |
1506 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor) = true; | |
1507 | ctx->values->put (new_ctx.object, ctor); | |
1508 | ctx = &new_ctx; | |
1509 | } | |
1510 | ||
09b42213 | 1511 | /* Shortcut trivial constructor/op=. */ |
1512 | if (trivial_fn_p (fun)) | |
1513 | { | |
9ebe2ea3 | 1514 | tree init = NULL_TREE; |
09b42213 | 1515 | if (call_expr_nargs (t) == 2) |
9ebe2ea3 | 1516 | init = convert_from_reference (get_nth_callarg (t, 1)); |
09b42213 | 1517 | else if (TREE_CODE (t) == AGGR_INIT_EXPR |
1518 | && AGGR_INIT_ZERO_FIRST (t)) | |
9ebe2ea3 | 1519 | init = build_zero_init (DECL_CONTEXT (fun), NULL_TREE, false); |
1520 | if (init) | |
1521 | { | |
1522 | tree op = get_nth_callarg (t, 0); | |
1523 | if (is_dummy_object (op)) | |
1524 | op = ctx->object; | |
1525 | else | |
1526 | op = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (op)), op); | |
1527 | tree set = build2 (MODIFY_EXPR, TREE_TYPE (op), op, init); | |
0ce12360 | 1528 | new_ctx.call = &new_call; |
1529 | return cxx_eval_constant_expression (&new_ctx, set, lval, | |
9ebe2ea3 | 1530 | non_constant_p, overflow_p); |
1531 | } | |
09b42213 | 1532 | } |
1533 | ||
8afcf831 | 1534 | /* We can't defer instantiating the function any longer. */ |
1535 | if (!DECL_INITIAL (fun) | |
1536 | && DECL_TEMPLOID_INSTANTIATION (fun)) | |
1537 | { | |
31db86df | 1538 | location_t save_loc = input_location; |
1539 | input_location = loc; | |
8afcf831 | 1540 | ++function_depth; |
1541 | instantiate_decl (fun, /*defer_ok*/false, /*expl_inst*/false); | |
1542 | --function_depth; | |
31db86df | 1543 | input_location = save_loc; |
8afcf831 | 1544 | } |
1545 | ||
09b42213 | 1546 | /* If in direct recursive call, optimize definition search. */ |
0ce12360 | 1547 | if (ctx && ctx->call && ctx->call->fundef && ctx->call->fundef->decl == fun) |
cf72f34d | 1548 | new_call.fundef = ctx->call->fundef; |
09b42213 | 1549 | else |
1550 | { | |
1551 | new_call.fundef = retrieve_constexpr_fundef (fun); | |
d2a9b1c1 | 1552 | if (new_call.fundef == NULL || new_call.fundef->body == NULL |
1553 | || fun == current_function_decl) | |
09b42213 | 1554 | { |
f83e6885 | 1555 | if (!ctx->quiet) |
09b42213 | 1556 | { |
d2a9b1c1 | 1557 | /* We need to check for current_function_decl here in case we're |
1558 | being called during cp_fold_function, because at that point | |
1559 | DECL_INITIAL is set properly and we have a fundef but we | |
1560 | haven't lowered invisirefs yet (c++/70344). */ | |
1561 | if (DECL_INITIAL (fun) == error_mark_node | |
1562 | || fun == current_function_decl) | |
a0efa758 | 1563 | error_at (loc, "%qD called in a constant expression before its " |
1564 | "definition is complete", fun); | |
1565 | else if (DECL_INITIAL (fun)) | |
09b42213 | 1566 | { |
33603066 | 1567 | /* The definition of fun was somehow unsuitable. But pretend |
1568 | that lambda static thunks don't exist. */ | |
1569 | if (!lambda_static_thunk_p (fun)) | |
1570 | error_at (loc, "%qD called in a constant expression", fun); | |
09b42213 | 1571 | explain_invalid_constexpr_fn (fun); |
1572 | } | |
1573 | else | |
1574 | error_at (loc, "%qD used before its definition", fun); | |
1575 | } | |
1576 | *non_constant_p = true; | |
1577 | return t; | |
1578 | } | |
1579 | } | |
9c96033c | 1580 | |
c8f6aeb1 | 1581 | bool non_constant_args = false; |
cf72f34d | 1582 | cxx_bind_parameters_in_call (ctx, t, &new_call, |
c8f6aeb1 | 1583 | non_constant_p, overflow_p, &non_constant_args); |
09b42213 | 1584 | if (*non_constant_p) |
1585 | return t; | |
1586 | ||
1587 | depth_ok = push_cx_call_context (t); | |
1588 | ||
c8f6aeb1 | 1589 | tree result = NULL_TREE; |
09b42213 | 1590 | |
c8f6aeb1 | 1591 | constexpr_call *entry = NULL; |
167a09fb | 1592 | if (depth_ok && !non_constant_args && ctx->strict) |
09b42213 | 1593 | { |
c8f6aeb1 | 1594 | new_call.hash = iterative_hash_template_arg |
1595 | (new_call.bindings, constexpr_fundef_hasher::hash (new_call.fundef)); | |
1596 | ||
1597 | /* If we have seen this call before, we are done. */ | |
1598 | maybe_initialize_constexpr_call_table (); | |
1599 | constexpr_call **slot | |
1600 | = constexpr_call_table->find_slot (&new_call, INSERT); | |
1601 | entry = *slot; | |
1602 | if (entry == NULL) | |
1603 | { | |
1604 | /* We need to keep a pointer to the entry, not just the slot, as the | |
1605 | slot can move in the call to cxx_eval_builtin_function_call. */ | |
1606 | *slot = entry = ggc_alloc<constexpr_call> (); | |
1607 | *entry = new_call; | |
1608 | } | |
2ba934c7 | 1609 | /* Calls that are in progress have their result set to NULL, |
c8f6aeb1 | 1610 | so that we can detect circular dependencies. */ |
1611 | else if (entry->result == NULL) | |
1612 | { | |
1613 | if (!ctx->quiet) | |
1614 | error ("call has circular dependency"); | |
1615 | *non_constant_p = true; | |
1616 | entry->result = result = error_mark_node; | |
1617 | } | |
1618 | else | |
1619 | result = entry->result; | |
09b42213 | 1620 | } |
1621 | ||
1622 | if (!depth_ok) | |
1623 | { | |
f83e6885 | 1624 | if (!ctx->quiet) |
5967b28b | 1625 | error ("%<constexpr%> evaluation depth exceeds maximum of %d (use " |
09b42213 | 1626 | "-fconstexpr-depth= to increase the maximum)", |
1627 | max_constexpr_depth); | |
1628 | *non_constant_p = true; | |
c8f6aeb1 | 1629 | result = error_mark_node; |
09b42213 | 1630 | } |
1631 | else | |
1632 | { | |
ab099088 | 1633 | if (result && result != error_mark_node) |
1634 | /* OK */; | |
1635 | else if (!DECL_SAVED_TREE (fun)) | |
1636 | { | |
1637 | /* When at_eof >= 2, cgraph has started throwing away | |
1638 | DECL_SAVED_TREE, so fail quietly. FIXME we get here because of | |
1639 | late code generation for VEC_INIT_EXPR, which needs to be | |
1640 | completely reconsidered. */ | |
1641 | gcc_assert (at_eof >= 2 && ctx->quiet); | |
1642 | *non_constant_p = true; | |
1643 | } | |
1644 | else | |
cf72f34d | 1645 | { |
4f7ebe46 | 1646 | tree body, parms, res; |
88a59139 | 1647 | |
4f7ebe46 | 1648 | /* Reuse or create a new unshared copy of this function's body. */ |
a050099a | 1649 | tree copy = get_fundef_copy (fun); |
1650 | body = TREE_PURPOSE (copy); | |
1651 | parms = TREE_VALUE (copy); | |
1652 | res = TREE_TYPE (copy); | |
88a59139 | 1653 | |
1654 | /* Associate the bindings with the remapped parms. */ | |
1655 | tree bound = new_call.bindings; | |
1656 | tree remapped = parms; | |
1657 | while (bound) | |
9c96033c | 1658 | { |
88a59139 | 1659 | tree oparm = TREE_PURPOSE (bound); |
1660 | tree arg = TREE_VALUE (bound); | |
1661 | gcc_assert (DECL_NAME (remapped) == DECL_NAME (oparm)); | |
5898f0d7 | 1662 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 1663 | arg = unshare_constructor (arg); |
88a59139 | 1664 | ctx->values->put (remapped, arg); |
1665 | bound = TREE_CHAIN (bound); | |
1666 | remapped = DECL_CHAIN (remapped); | |
9c96033c | 1667 | } |
88a59139 | 1668 | /* Add the RESULT_DECL to the values map, too. */ |
1669 | tree slot = NULL_TREE; | |
1670 | if (DECL_BY_REFERENCE (res)) | |
9c96033c | 1671 | { |
88a59139 | 1672 | slot = AGGR_INIT_EXPR_SLOT (t); |
1673 | tree addr = build_address (slot); | |
1674 | addr = build_nop (TREE_TYPE (res), addr); | |
1675 | ctx->values->put (res, addr); | |
1676 | ctx->values->put (slot, NULL_TREE); | |
1677 | } | |
1678 | else | |
1679 | ctx->values->put (res, NULL_TREE); | |
9c96033c | 1680 | |
4f7ebe46 | 1681 | /* Track the callee's evaluated SAVE_EXPRs so that we can forget |
1682 | their values after the call. */ | |
1683 | constexpr_ctx ctx_with_save_exprs = *ctx; | |
1684 | hash_set<tree> save_exprs; | |
1685 | ctx_with_save_exprs.save_exprs = &save_exprs; | |
43b7271d | 1686 | ctx_with_save_exprs.call = &new_call; |
4f7ebe46 | 1687 | |
88a59139 | 1688 | tree jump_target = NULL_TREE; |
4f7ebe46 | 1689 | cxx_eval_constant_expression (&ctx_with_save_exprs, body, |
88a59139 | 1690 | lval, non_constant_p, overflow_p, |
1691 | &jump_target); | |
9c96033c | 1692 | |
88a59139 | 1693 | if (DECL_CONSTRUCTOR_P (fun)) |
1694 | /* This can be null for a subobject constructor call, in | |
1695 | which case what we care about is the initialization | |
1696 | side-effects rather than the value. We could get at the | |
1697 | value by evaluating *this, but we don't bother; there's | |
1698 | no need to put such a call in the hash table. */ | |
1699 | result = lval ? ctx->object : ctx->ctor; | |
1700 | else if (VOID_TYPE_P (TREE_TYPE (res))) | |
1701 | result = void_node; | |
1702 | else | |
1703 | { | |
1704 | result = *ctx->values->get (slot ? slot : res); | |
1705 | if (result == NULL_TREE && !*non_constant_p) | |
9c96033c | 1706 | { |
88a59139 | 1707 | if (!ctx->quiet) |
5967b28b | 1708 | error ("%<constexpr%> call flows off the end " |
88a59139 | 1709 | "of the function"); |
1710 | *non_constant_p = true; | |
9c96033c | 1711 | } |
9c96033c | 1712 | } |
88a59139 | 1713 | |
4f7ebe46 | 1714 | /* Forget the saved values of the callee's SAVE_EXPRs. */ |
1715 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
1716 | iter != save_exprs.end(); ++iter) | |
1717 | ctx_with_save_exprs.values->remove (*iter); | |
1718 | ||
88a59139 | 1719 | /* Remove the parms/result from the values map. Is it worth |
1720 | bothering to do this when the map itself is only live for | |
1721 | one constexpr evaluation? If so, maybe also clear out | |
1722 | other vars from call, maybe in BIND_EXPR handling? */ | |
1723 | ctx->values->remove (res); | |
1724 | if (slot) | |
1725 | ctx->values->remove (slot); | |
1726 | for (tree parm = parms; parm; parm = TREE_CHAIN (parm)) | |
1727 | ctx->values->remove (parm); | |
4f7ebe46 | 1728 | |
1729 | /* Make the unshared function copy we used available for re-use. */ | |
1730 | save_fundef_copy (fun, copy); | |
cf72f34d | 1731 | } |
9c96033c | 1732 | |
09b42213 | 1733 | if (result == error_mark_node) |
1734 | *non_constant_p = true; | |
c3f376bf | 1735 | if (*non_constant_p || *overflow_p) |
c8f6aeb1 | 1736 | result = error_mark_node; |
88a59139 | 1737 | else if (!result) |
9c96033c | 1738 | result = void_node; |
c8f6aeb1 | 1739 | if (entry) |
1740 | entry->result = result; | |
09b42213 | 1741 | } |
1742 | ||
c6d97004 | 1743 | /* The result of a constexpr function must be completely initialized. */ |
1744 | if (TREE_CODE (result) == CONSTRUCTOR) | |
79cdb4f5 | 1745 | clear_no_implicit_zero (result); |
c6d97004 | 1746 | |
09b42213 | 1747 | pop_cx_call_context (); |
e283bb4f | 1748 | return unshare_constructor (result); |
09b42213 | 1749 | } |
1750 | ||
1751 | /* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */ | |
1752 | ||
1753 | bool | |
1754 | reduced_constant_expression_p (tree t) | |
1755 | { | |
1756 | switch (TREE_CODE (t)) | |
1757 | { | |
1758 | case PTRMEM_CST: | |
1759 | /* Even if we can't lower this yet, it's constant. */ | |
1760 | return true; | |
1761 | ||
1762 | case CONSTRUCTOR: | |
1763 | /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */ | |
56da7fe6 | 1764 | tree idx, val, field; unsigned HOST_WIDE_INT i; |
1765 | if (CONSTRUCTOR_NO_IMPLICIT_ZERO (t)) | |
c4210852 | 1766 | { |
1767 | if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE) | |
1768 | /* An initialized vector would have a VECTOR_CST. */ | |
1769 | return false; | |
1770 | else | |
1771 | field = next_initializable_field (TYPE_FIELDS (TREE_TYPE (t))); | |
1772 | } | |
56da7fe6 | 1773 | else |
1774 | field = NULL_TREE; | |
1775 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t), i, idx, val) | |
ce4ffd9e | 1776 | { |
56da7fe6 | 1777 | if (!val) |
ce4ffd9e | 1778 | /* We're in the middle of initializing this element. */ |
1779 | return false; | |
56da7fe6 | 1780 | if (!reduced_constant_expression_p (val)) |
ce4ffd9e | 1781 | return false; |
56da7fe6 | 1782 | if (field) |
1783 | { | |
1784 | if (idx != field) | |
1785 | return false; | |
1786 | field = next_initializable_field (DECL_CHAIN (field)); | |
1787 | } | |
ce4ffd9e | 1788 | } |
56da7fe6 | 1789 | if (field) |
1790 | return false; | |
1791 | else if (CONSTRUCTOR_NO_IMPLICIT_ZERO (t)) | |
1792 | /* All the fields are initialized. */ | |
1793 | CONSTRUCTOR_NO_IMPLICIT_ZERO (t) = false; | |
09b42213 | 1794 | return true; |
1795 | ||
1796 | default: | |
1797 | /* FIXME are we calling this too much? */ | |
1798 | return initializer_constant_valid_p (t, TREE_TYPE (t)) != NULL_TREE; | |
1799 | } | |
1800 | } | |
1801 | ||
1802 | /* Some expressions may have constant operands but are not constant | |
1803 | themselves, such as 1/0. Call this function (or rather, the macro | |
1804 | following it) to check for that condition. | |
1805 | ||
1806 | We only call this in places that require an arithmetic constant, not in | |
1807 | places where we might have a non-constant expression that can be a | |
1808 | component of a constant expression, such as the address of a constexpr | |
1809 | variable that might be dereferenced later. */ | |
1810 | ||
1811 | static bool | |
1812 | verify_constant (tree t, bool allow_non_constant, bool *non_constant_p, | |
1813 | bool *overflow_p) | |
1814 | { | |
1815 | if (!*non_constant_p && !reduced_constant_expression_p (t)) | |
1816 | { | |
1817 | if (!allow_non_constant) | |
1818 | error ("%q+E is not a constant expression", t); | |
1819 | *non_constant_p = true; | |
1820 | } | |
1821 | if (TREE_OVERFLOW_P (t)) | |
1822 | { | |
1823 | if (!allow_non_constant) | |
1824 | { | |
1825 | permerror (input_location, "overflow in constant expression"); | |
1826 | /* If we're being permissive (and are in an enforcing | |
1827 | context), ignore the overflow. */ | |
1828 | if (flag_permissive) | |
1829 | return *non_constant_p; | |
1830 | } | |
1831 | *overflow_p = true; | |
1832 | } | |
1833 | return *non_constant_p; | |
1834 | } | |
1835 | ||
2b035ffe | 1836 | /* Check whether the shift operation with code CODE and type TYPE on LHS |
1837 | and RHS is undefined. If it is, give an error with an explanation, | |
1838 | and return true; return false otherwise. */ | |
1839 | ||
1840 | static bool | |
1841 | cxx_eval_check_shift_p (location_t loc, const constexpr_ctx *ctx, | |
1842 | enum tree_code code, tree type, tree lhs, tree rhs) | |
1843 | { | |
1844 | if ((code != LSHIFT_EXPR && code != RSHIFT_EXPR) | |
1845 | || TREE_CODE (lhs) != INTEGER_CST | |
1846 | || TREE_CODE (rhs) != INTEGER_CST) | |
1847 | return false; | |
1848 | ||
1849 | tree lhstype = TREE_TYPE (lhs); | |
1850 | unsigned HOST_WIDE_INT uprec = TYPE_PRECISION (TREE_TYPE (lhs)); | |
1851 | ||
1852 | /* [expr.shift] The behavior is undefined if the right operand | |
1853 | is negative, or greater than or equal to the length in bits | |
1854 | of the promoted left operand. */ | |
1855 | if (tree_int_cst_sgn (rhs) == -1) | |
1856 | { | |
1857 | if (!ctx->quiet) | |
91d87e22 | 1858 | permerror (loc, "right operand of shift expression %q+E is negative", |
1859 | build2_loc (loc, code, type, lhs, rhs)); | |
1860 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1861 | } |
1862 | if (compare_tree_int (rhs, uprec) >= 0) | |
1863 | { | |
1864 | if (!ctx->quiet) | |
91d87e22 | 1865 | permerror (loc, "right operand of shift expression %q+E is >= than " |
1866 | "the precision of the left operand", | |
1867 | build2_loc (loc, code, type, lhs, rhs)); | |
1868 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1869 | } |
1870 | ||
1871 | /* The value of E1 << E2 is E1 left-shifted E2 bit positions; [...] | |
1872 | if E1 has a signed type and non-negative value, and E1x2^E2 is | |
1873 | representable in the corresponding unsigned type of the result type, | |
1874 | then that value, converted to the result type, is the resulting value; | |
1875 | otherwise, the behavior is undefined. */ | |
1876 | if (code == LSHIFT_EXPR && !TYPE_UNSIGNED (lhstype) | |
1877 | && (cxx_dialect >= cxx11)) | |
1878 | { | |
1879 | if (tree_int_cst_sgn (lhs) == -1) | |
1880 | { | |
1881 | if (!ctx->quiet) | |
91d87e22 | 1882 | permerror (loc, |
1883 | "left operand of shift expression %q+E is negative", | |
1884 | build2_loc (loc, code, type, lhs, rhs)); | |
1885 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1886 | } |
1887 | /* For signed x << y the following: | |
1888 | (unsigned) x >> ((prec (lhs) - 1) - y) | |
1889 | if > 1, is undefined. The right-hand side of this formula | |
1890 | is the highest bit of the LHS that can be set (starting from 0), | |
1891 | so that the shift doesn't overflow. We then right-shift the LHS | |
1892 | to see whether any other bit is set making the original shift | |
1893 | undefined -- the result is not representable in the corresponding | |
1894 | unsigned type. */ | |
1895 | tree t = build_int_cst (unsigned_type_node, uprec - 1); | |
1896 | t = fold_build2 (MINUS_EXPR, unsigned_type_node, t, rhs); | |
1897 | tree ulhs = fold_convert (unsigned_type_for (lhstype), lhs); | |
1898 | t = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ulhs), ulhs, t); | |
1899 | if (tree_int_cst_lt (integer_one_node, t)) | |
1900 | { | |
1901 | if (!ctx->quiet) | |
91d87e22 | 1902 | permerror (loc, "shift expression %q+E overflows", |
1903 | build2_loc (loc, code, type, lhs, rhs)); | |
1904 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1905 | } |
1906 | } | |
1907 | return false; | |
1908 | } | |
1909 | ||
09b42213 | 1910 | /* Subroutine of cxx_eval_constant_expression. |
1911 | Attempt to reduce the unary expression tree T to a compile time value. | |
1912 | If successful, return the value. Otherwise issue a diagnostic | |
1913 | and return error_mark_node. */ | |
1914 | ||
1915 | static tree | |
cf72f34d | 1916 | cxx_eval_unary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 1917 | bool /*lval*/, |
09b42213 | 1918 | bool *non_constant_p, bool *overflow_p) |
1919 | { | |
1920 | tree r; | |
1921 | tree orig_arg = TREE_OPERAND (t, 0); | |
c8f6aeb1 | 1922 | tree arg = cxx_eval_constant_expression (ctx, orig_arg, /*lval*/false, |
1923 | non_constant_p, overflow_p); | |
09b42213 | 1924 | VERIFY_CONSTANT (arg); |
93add516 | 1925 | location_t loc = EXPR_LOCATION (t); |
1926 | enum tree_code code = TREE_CODE (t); | |
1927 | tree type = TREE_TYPE (t); | |
1928 | r = fold_unary_loc (loc, code, type, arg); | |
1929 | if (r == NULL_TREE) | |
1930 | { | |
1931 | if (arg == orig_arg) | |
1932 | r = t; | |
1933 | else | |
1934 | r = build1_loc (loc, code, type, arg); | |
1935 | } | |
09b42213 | 1936 | VERIFY_CONSTANT (r); |
1937 | return r; | |
1938 | } | |
1939 | ||
46fad8d5 | 1940 | /* Helper function for cxx_eval_binary_expression. Try to optimize |
1941 | original POINTER_PLUS_EXPR T, LHS p+ RHS, return NULL_TREE if the | |
1942 | generic folding should be used. */ | |
1943 | ||
1944 | static tree | |
1945 | cxx_fold_pointer_plus_expression (const constexpr_ctx *ctx, tree t, | |
1946 | tree lhs, tree rhs, bool *non_constant_p, | |
1947 | bool *overflow_p) | |
1948 | { | |
1949 | STRIP_NOPS (lhs); | |
1950 | if (TREE_CODE (lhs) != ADDR_EXPR) | |
1951 | return NULL_TREE; | |
1952 | ||
1953 | lhs = TREE_OPERAND (lhs, 0); | |
1954 | ||
1955 | /* &A[i] p+ j => &A[i + j] */ | |
1956 | if (TREE_CODE (lhs) == ARRAY_REF | |
1957 | && TREE_CODE (TREE_OPERAND (lhs, 1)) == INTEGER_CST | |
1958 | && TREE_CODE (rhs) == INTEGER_CST | |
1959 | && TYPE_SIZE_UNIT (TREE_TYPE (lhs)) | |
1960 | && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (lhs))) == INTEGER_CST) | |
1961 | { | |
1962 | tree orig_type = TREE_TYPE (t); | |
1963 | location_t loc = EXPR_LOCATION (t); | |
1964 | tree type = TREE_TYPE (lhs); | |
1965 | ||
1966 | t = fold_convert_loc (loc, ssizetype, TREE_OPERAND (lhs, 1)); | |
1967 | tree nelts = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (lhs, 0))); | |
1968 | nelts = cxx_eval_constant_expression (ctx, nelts, false, non_constant_p, | |
1969 | overflow_p); | |
1970 | if (*non_constant_p) | |
1971 | return NULL_TREE; | |
1972 | /* Don't fold an out-of-bound access. */ | |
1973 | if (!tree_int_cst_le (t, nelts)) | |
1974 | return NULL_TREE; | |
1975 | rhs = cp_fold_convert (ssizetype, rhs); | |
1976 | /* Don't fold if rhs can't be divided exactly by TYPE_SIZE_UNIT. | |
1977 | constexpr int A[1]; ... (char *)&A[0] + 1 */ | |
1978 | if (!integer_zerop (fold_build2_loc (loc, TRUNC_MOD_EXPR, sizetype, | |
1979 | rhs, TYPE_SIZE_UNIT (type)))) | |
1980 | return NULL_TREE; | |
1981 | /* Make sure to treat the second operand of POINTER_PLUS_EXPR | |
1982 | as signed. */ | |
1983 | rhs = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, rhs, | |
1984 | TYPE_SIZE_UNIT (type)); | |
1985 | t = size_binop_loc (loc, PLUS_EXPR, rhs, t); | |
1986 | t = build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (lhs, 0), | |
1987 | t, NULL_TREE, NULL_TREE); | |
1988 | t = cp_build_addr_expr (t, tf_warning_or_error); | |
1989 | t = cp_fold_convert (orig_type, t); | |
1990 | return cxx_eval_constant_expression (ctx, t, /*lval*/false, | |
1991 | non_constant_p, overflow_p); | |
1992 | } | |
1993 | ||
1994 | return NULL_TREE; | |
1995 | } | |
1996 | ||
09b42213 | 1997 | /* Subroutine of cxx_eval_constant_expression. |
1998 | Like cxx_eval_unary_expression, except for binary expressions. */ | |
1999 | ||
2000 | static tree | |
cf72f34d | 2001 | cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 2002 | bool /*lval*/, |
09b42213 | 2003 | bool *non_constant_p, bool *overflow_p) |
2004 | { | |
f7ef5392 | 2005 | tree r = NULL_TREE; |
09b42213 | 2006 | tree orig_lhs = TREE_OPERAND (t, 0); |
2007 | tree orig_rhs = TREE_OPERAND (t, 1); | |
2008 | tree lhs, rhs; | |
c8f6aeb1 | 2009 | lhs = cxx_eval_constant_expression (ctx, orig_lhs, /*lval*/false, |
b2a43197 | 2010 | non_constant_p, overflow_p); |
6d6737d9 | 2011 | /* Don't VERIFY_CONSTANT here, it's unnecessary and will break pointer |
2012 | subtraction. */ | |
2013 | if (*non_constant_p) | |
2014 | return t; | |
c8f6aeb1 | 2015 | rhs = cxx_eval_constant_expression (ctx, orig_rhs, /*lval*/false, |
b2a43197 | 2016 | non_constant_p, overflow_p); |
6d6737d9 | 2017 | if (*non_constant_p) |
2018 | return t; | |
93add516 | 2019 | |
2020 | location_t loc = EXPR_LOCATION (t); | |
2021 | enum tree_code code = TREE_CODE (t); | |
2022 | tree type = TREE_TYPE (t); | |
f7ef5392 | 2023 | |
2024 | if (code == EQ_EXPR || code == NE_EXPR) | |
2025 | { | |
2026 | bool is_code_eq = (code == EQ_EXPR); | |
2027 | ||
2028 | if (TREE_CODE (lhs) == PTRMEM_CST | |
2029 | && TREE_CODE (rhs) == PTRMEM_CST) | |
2030 | r = constant_boolean_node (cp_tree_equal (lhs, rhs) == is_code_eq, | |
2031 | type); | |
2032 | else if ((TREE_CODE (lhs) == PTRMEM_CST | |
2033 | || TREE_CODE (rhs) == PTRMEM_CST) | |
2034 | && (null_member_pointer_value_p (lhs) | |
2035 | || null_member_pointer_value_p (rhs))) | |
2036 | r = constant_boolean_node (!is_code_eq, type); | |
f31f4e9c | 2037 | else if (TREE_CODE (lhs) == PTRMEM_CST) |
2038 | lhs = cplus_expand_constant (lhs); | |
2039 | else if (TREE_CODE (rhs) == PTRMEM_CST) | |
2040 | rhs = cplus_expand_constant (rhs); | |
f7ef5392 | 2041 | } |
cb768824 | 2042 | if (code == POINTER_PLUS_EXPR && !*non_constant_p |
2043 | && integer_zerop (lhs) && !integer_zerop (rhs)) | |
2044 | { | |
2045 | if (!ctx->quiet) | |
2046 | error ("arithmetic involving a null pointer in %qE", lhs); | |
2047 | return t; | |
2048 | } | |
46fad8d5 | 2049 | else if (code == POINTER_PLUS_EXPR) |
2050 | r = cxx_fold_pointer_plus_expression (ctx, t, lhs, rhs, non_constant_p, | |
2051 | overflow_p); | |
f7ef5392 | 2052 | |
2053 | if (r == NULL_TREE) | |
2054 | r = fold_binary_loc (loc, code, type, lhs, rhs); | |
2055 | ||
93add516 | 2056 | if (r == NULL_TREE) |
2057 | { | |
2058 | if (lhs == orig_lhs && rhs == orig_rhs) | |
2059 | r = t; | |
2060 | else | |
2061 | r = build2_loc (loc, code, type, lhs, rhs); | |
2062 | } | |
2b035ffe | 2063 | else if (cxx_eval_check_shift_p (loc, ctx, code, type, lhs, rhs)) |
2064 | *non_constant_p = true; | |
6d6737d9 | 2065 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
2066 | a local array in a constexpr function. */ | |
2067 | bool ptr = POINTER_TYPE_P (TREE_TYPE (lhs)); | |
35f2c28f | 2068 | if (!ptr) |
aae7465c | 2069 | VERIFY_CONSTANT (r); |
09b42213 | 2070 | return r; |
2071 | } | |
2072 | ||
2073 | /* Subroutine of cxx_eval_constant_expression. | |
2074 | Attempt to evaluate condition expressions. Dead branches are not | |
2075 | looked into. */ | |
2076 | ||
2077 | static tree | |
cf72f34d | 2078 | cxx_eval_conditional_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2079 | bool lval, |
00f21715 | 2080 | bool *non_constant_p, bool *overflow_p, |
2081 | tree *jump_target) | |
09b42213 | 2082 | { |
cf72f34d | 2083 | tree val = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
c8f6aeb1 | 2084 | /*lval*/false, |
b2a43197 | 2085 | non_constant_p, overflow_p); |
09b42213 | 2086 | VERIFY_CONSTANT (val); |
2087 | /* Don't VERIFY_CONSTANT the other operands. */ | |
2088 | if (integer_zerop (val)) | |
cf72f34d | 2089 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), |
1227ba74 | 2090 | lval, |
00f21715 | 2091 | non_constant_p, overflow_p, |
2092 | jump_target); | |
cf72f34d | 2093 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2094 | lval, |
00f21715 | 2095 | non_constant_p, overflow_p, |
2096 | jump_target); | |
09b42213 | 2097 | } |
2098 | ||
31595caf | 2099 | /* Subroutine of cxx_eval_constant_expression. |
2100 | Attempt to evaluate vector condition expressions. Unlike | |
2101 | cxx_eval_conditional_expression, VEC_COND_EXPR acts like a normal | |
2102 | ternary arithmetics operation, where all 3 arguments have to be | |
2103 | evaluated as constants and then folding computes the result from | |
2104 | them. */ | |
2105 | ||
2106 | static tree | |
2107 | cxx_eval_vector_conditional_expression (const constexpr_ctx *ctx, tree t, | |
2108 | bool *non_constant_p, bool *overflow_p) | |
2109 | { | |
2110 | tree arg1 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
2111 | /*lval*/false, | |
2112 | non_constant_p, overflow_p); | |
2113 | VERIFY_CONSTANT (arg1); | |
2114 | tree arg2 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
2115 | /*lval*/false, | |
2116 | non_constant_p, overflow_p); | |
2117 | VERIFY_CONSTANT (arg2); | |
2118 | tree arg3 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
2119 | /*lval*/false, | |
2120 | non_constant_p, overflow_p); | |
2121 | VERIFY_CONSTANT (arg3); | |
2122 | location_t loc = EXPR_LOCATION (t); | |
2123 | tree type = TREE_TYPE (t); | |
2124 | tree r = fold_ternary_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2125 | if (r == NULL_TREE) | |
2126 | { | |
2127 | if (arg1 == TREE_OPERAND (t, 0) | |
2128 | && arg2 == TREE_OPERAND (t, 1) | |
2129 | && arg3 == TREE_OPERAND (t, 2)) | |
2130 | r = t; | |
2131 | else | |
2132 | r = build3_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2133 | } | |
2134 | VERIFY_CONSTANT (r); | |
2135 | return r; | |
2136 | } | |
2137 | ||
7963b19d | 2138 | /* Returns less than, equal to, or greater than zero if KEY is found to be |
2139 | less than, to match, or to be greater than the constructor_elt's INDEX. */ | |
2140 | ||
2141 | static int | |
2142 | array_index_cmp (tree key, tree index) | |
2143 | { | |
2144 | gcc_assert (TREE_CODE (key) == INTEGER_CST); | |
2145 | ||
2146 | switch (TREE_CODE (index)) | |
2147 | { | |
2148 | case INTEGER_CST: | |
2149 | return tree_int_cst_compare (key, index); | |
2150 | case RANGE_EXPR: | |
2151 | { | |
2152 | tree lo = TREE_OPERAND (index, 0); | |
2153 | tree hi = TREE_OPERAND (index, 1); | |
2154 | if (tree_int_cst_lt (key, lo)) | |
2155 | return -1; | |
2156 | else if (tree_int_cst_lt (hi, key)) | |
2157 | return 1; | |
2158 | else | |
2159 | return 0; | |
2160 | } | |
2161 | default: | |
2162 | gcc_unreachable (); | |
2163 | } | |
2164 | } | |
2165 | ||
2166 | /* Returns the index of the constructor_elt of ARY which matches DINDEX, or -1 | |
2167 | if none. If INSERT is true, insert a matching element rather than fail. */ | |
2168 | ||
2169 | static HOST_WIDE_INT | |
2170 | find_array_ctor_elt (tree ary, tree dindex, bool insert = false) | |
2171 | { | |
2172 | if (tree_int_cst_sgn (dindex) < 0) | |
2173 | return -1; | |
2174 | ||
2175 | unsigned HOST_WIDE_INT i = tree_to_uhwi (dindex); | |
2176 | vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (ary); | |
2177 | unsigned HOST_WIDE_INT len = vec_safe_length (elts); | |
2178 | ||
2179 | unsigned HOST_WIDE_INT end = len; | |
2180 | unsigned HOST_WIDE_INT begin = 0; | |
2181 | ||
2182 | /* If the last element of the CONSTRUCTOR has its own index, we can assume | |
2183 | that the same is true of the other elements and index directly. */ | |
2184 | if (end > 0) | |
2185 | { | |
2186 | tree cindex = (*elts)[end-1].index; | |
2187 | if (TREE_CODE (cindex) == INTEGER_CST | |
2188 | && compare_tree_int (cindex, end-1) == 0) | |
2189 | { | |
2190 | if (i < end) | |
2191 | return i; | |
2192 | else | |
2193 | begin = end; | |
2194 | } | |
2195 | } | |
2196 | ||
2197 | /* Otherwise, find a matching index by means of a binary search. */ | |
2198 | while (begin != end) | |
2199 | { | |
2200 | unsigned HOST_WIDE_INT middle = (begin + end) / 2; | |
f0b916c7 | 2201 | constructor_elt &elt = (*elts)[middle]; |
2202 | tree idx = elt.index; | |
7963b19d | 2203 | |
f0b916c7 | 2204 | int cmp = array_index_cmp (dindex, idx); |
7963b19d | 2205 | if (cmp < 0) |
2206 | end = middle; | |
2207 | else if (cmp > 0) | |
2208 | begin = middle + 1; | |
2209 | else | |
f0b916c7 | 2210 | { |
2211 | if (insert && TREE_CODE (idx) == RANGE_EXPR) | |
2212 | { | |
2213 | /* We need to split the range. */ | |
2214 | constructor_elt e; | |
2215 | tree lo = TREE_OPERAND (idx, 0); | |
2216 | tree hi = TREE_OPERAND (idx, 1); | |
2217 | if (tree_int_cst_lt (lo, dindex)) | |
2218 | { | |
2219 | /* There are still some lower elts; shorten the range. */ | |
2220 | tree new_hi = int_const_binop (MINUS_EXPR, dindex, | |
2221 | size_one_node); | |
2222 | if (tree_int_cst_equal (lo, new_hi)) | |
2223 | /* Only one element left, no longer a range. */ | |
2224 | elt.index = lo; | |
2225 | else | |
2226 | TREE_OPERAND (idx, 1) = new_hi; | |
2227 | /* Append the element we want to insert. */ | |
2228 | ++middle; | |
2229 | e.index = dindex; | |
e283bb4f | 2230 | e.value = unshare_constructor (elt.value); |
f0b916c7 | 2231 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle, e); |
2232 | } | |
2233 | else | |
2234 | /* No lower elts, the range elt is now ours. */ | |
2235 | elt.index = dindex; | |
2236 | ||
2237 | if (tree_int_cst_lt (dindex, hi)) | |
2238 | { | |
2239 | /* There are still some higher elts; append a range. */ | |
2240 | tree new_lo = int_const_binop (PLUS_EXPR, dindex, | |
2241 | size_one_node); | |
2242 | if (tree_int_cst_equal (new_lo, hi)) | |
2243 | e.index = hi; | |
2244 | else | |
2245 | e.index = build2 (RANGE_EXPR, sizetype, new_lo, hi); | |
e283bb4f | 2246 | e.value = unshare_constructor (elt.value); |
f0b916c7 | 2247 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle+1, e); |
2248 | } | |
2249 | } | |
2250 | return middle; | |
2251 | } | |
7963b19d | 2252 | } |
2253 | ||
2254 | if (insert) | |
2255 | { | |
2256 | constructor_elt e = { dindex, NULL_TREE }; | |
2257 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), end, e); | |
2258 | return end; | |
2259 | } | |
2260 | ||
2261 | return -1; | |
2262 | } | |
2263 | ||
40df9099 | 2264 | /* Under the control of CTX, issue a detailed diagnostic for |
2265 | an out-of-bounds subscript INDEX into the expression ARRAY. */ | |
2266 | ||
2267 | static void | |
2268 | diag_array_subscript (const constexpr_ctx *ctx, tree array, tree index) | |
2269 | { | |
2270 | if (!ctx->quiet) | |
2271 | { | |
2272 | tree arraytype = TREE_TYPE (array); | |
2273 | ||
2274 | /* Convert the unsigned array subscript to a signed integer to avoid | |
2275 | printing huge numbers for small negative values. */ | |
2276 | tree sidx = fold_convert (ssizetype, index); | |
2277 | if (DECL_P (array)) | |
2278 | { | |
d7d265db | 2279 | if (TYPE_DOMAIN (arraytype)) |
2280 | error ("array subscript value %qE is outside the bounds " | |
2281 | "of array %qD of type %qT", sidx, array, arraytype); | |
2282 | else | |
2283 | error ("non-zero array subscript %qE is used with array %qD of " | |
2284 | "type %qT with unknown bounds", sidx, array, arraytype); | |
40df9099 | 2285 | inform (DECL_SOURCE_LOCATION (array), "declared here"); |
2286 | } | |
d7d265db | 2287 | else if (TYPE_DOMAIN (arraytype)) |
40df9099 | 2288 | error ("array subscript value %qE is outside the bounds " |
2289 | "of array type %qT", sidx, arraytype); | |
d7d265db | 2290 | else |
2291 | error ("non-zero array subscript %qE is used with array of type %qT " | |
2292 | "with unknown bounds", sidx, arraytype); | |
40df9099 | 2293 | } |
2294 | } | |
7963b19d | 2295 | |
92fe8840 | 2296 | /* Extract element INDEX consisting of CHARS_PER_ELT chars from |
2297 | STRING_CST STRING. */ | |
2298 | ||
2299 | static tree | |
2300 | extract_string_elt (tree string, unsigned chars_per_elt, unsigned index) | |
2301 | { | |
2302 | tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (string))); | |
2303 | tree r; | |
2304 | ||
2305 | if (chars_per_elt == 1) | |
2306 | r = build_int_cst (type, TREE_STRING_POINTER (string)[index]); | |
2307 | else | |
2308 | { | |
2309 | const unsigned char *ptr | |
2310 | = ((const unsigned char *)TREE_STRING_POINTER (string) | |
2311 | + index * chars_per_elt); | |
2312 | r = native_interpret_expr (type, ptr, chars_per_elt); | |
2313 | } | |
2314 | return r; | |
2315 | } | |
2316 | ||
09b42213 | 2317 | /* Subroutine of cxx_eval_constant_expression. |
2318 | Attempt to reduce a reference to an array slot. */ | |
2319 | ||
2320 | static tree | |
cf72f34d | 2321 | cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2322 | bool lval, |
09b42213 | 2323 | bool *non_constant_p, bool *overflow_p) |
2324 | { | |
2325 | tree oldary = TREE_OPERAND (t, 0); | |
cf72f34d | 2326 | tree ary = cxx_eval_constant_expression (ctx, oldary, |
1227ba74 | 2327 | lval, |
b2a43197 | 2328 | non_constant_p, overflow_p); |
09b42213 | 2329 | tree index, oldidx; |
cf3cefc9 | 2330 | HOST_WIDE_INT i = 0; |
2331 | tree elem_type = NULL_TREE; | |
2332 | unsigned len = 0, elem_nchars = 1; | |
09b42213 | 2333 | if (*non_constant_p) |
2334 | return t; | |
2335 | oldidx = TREE_OPERAND (t, 1); | |
cf72f34d | 2336 | index = cxx_eval_constant_expression (ctx, oldidx, |
f83e6885 | 2337 | false, |
b2a43197 | 2338 | non_constant_p, overflow_p); |
09b42213 | 2339 | VERIFY_CONSTANT (index); |
cf3cefc9 | 2340 | if (!lval) |
09b42213 | 2341 | { |
cf3cefc9 | 2342 | elem_type = TREE_TYPE (TREE_TYPE (ary)); |
2343 | if (TREE_CODE (ary) == VIEW_CONVERT_EXPR | |
2344 | && VECTOR_TYPE_P (TREE_TYPE (TREE_OPERAND (ary, 0))) | |
2345 | && TREE_TYPE (t) == TREE_TYPE (TREE_TYPE (TREE_OPERAND (ary, 0)))) | |
2346 | ary = TREE_OPERAND (ary, 0); | |
2347 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2348 | len = CONSTRUCTOR_NELTS (ary); | |
2349 | else if (TREE_CODE (ary) == STRING_CST) | |
2350 | { | |
2351 | elem_nchars = (TYPE_PRECISION (elem_type) | |
2352 | / TYPE_PRECISION (char_type_node)); | |
2353 | len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars; | |
2354 | } | |
2355 | else if (TREE_CODE (ary) == VECTOR_CST) | |
f08ee65f | 2356 | /* We don't create variable-length VECTOR_CSTs. */ |
2357 | len = VECTOR_CST_NELTS (ary).to_constant (); | |
cf3cefc9 | 2358 | else |
2359 | { | |
2360 | /* We can't do anything with other tree codes, so use | |
2361 | VERIFY_CONSTANT to complain and fail. */ | |
2362 | VERIFY_CONSTANT (ary); | |
2363 | gcc_unreachable (); | |
2364 | } | |
aed8dc7f | 2365 | |
cf3cefc9 | 2366 | if (!tree_fits_shwi_p (index) |
2367 | || (i = tree_to_shwi (index)) < 0) | |
2368 | { | |
2369 | diag_array_subscript (ctx, ary, index); | |
2370 | *non_constant_p = true; | |
2371 | return t; | |
2372 | } | |
7963b19d | 2373 | } |
2374 | ||
7345b977 | 2375 | tree nelts; |
2376 | if (TREE_CODE (TREE_TYPE (ary)) == ARRAY_TYPE) | |
d7d265db | 2377 | { |
2378 | if (TYPE_DOMAIN (TREE_TYPE (ary))) | |
2379 | nelts = array_type_nelts_top (TREE_TYPE (ary)); | |
2380 | else | |
2381 | nelts = size_zero_node; | |
2382 | } | |
7345b977 | 2383 | else if (VECTOR_TYPE_P (TREE_TYPE (ary))) |
2384 | nelts = size_int (TYPE_VECTOR_SUBPARTS (TREE_TYPE (ary))); | |
2385 | else | |
2386 | gcc_unreachable (); | |
2387 | ||
ce6a6978 | 2388 | /* For VLAs, the number of elements won't be an integer constant. */ |
2389 | nelts = cxx_eval_constant_expression (ctx, nelts, false, non_constant_p, | |
2390 | overflow_p); | |
2391 | VERIFY_CONSTANT (nelts); | |
0acc6340 | 2392 | if ((lval |
2393 | ? !tree_int_cst_le (index, nelts) | |
2394 | : !tree_int_cst_lt (index, nelts)) | |
2395 | || tree_int_cst_sgn (index) < 0) | |
ce6a6978 | 2396 | { |
40df9099 | 2397 | diag_array_subscript (ctx, ary, index); |
ce6a6978 | 2398 | *non_constant_p = true; |
2399 | return t; | |
2400 | } | |
2401 | ||
cf3cefc9 | 2402 | if (lval && ary == oldary && index == oldidx) |
2403 | return t; | |
2404 | else if (lval) | |
2405 | return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL); | |
2406 | ||
7963b19d | 2407 | bool found; |
2408 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2409 | { | |
2410 | HOST_WIDE_INT ix = find_array_ctor_elt (ary, index); | |
2411 | found = (ix >= 0); | |
2412 | if (found) | |
2413 | i = ix; | |
aed8dc7f | 2414 | } |
7963b19d | 2415 | else |
2416 | found = (i < len); | |
aed8dc7f | 2417 | |
14869f28 | 2418 | if (found) |
2419 | { | |
2420 | tree r; | |
2421 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2422 | r = (*CONSTRUCTOR_ELTS (ary))[i].value; | |
2423 | else if (TREE_CODE (ary) == VECTOR_CST) | |
2424 | r = VECTOR_CST_ELT (ary, i); | |
14869f28 | 2425 | else |
92fe8840 | 2426 | r = extract_string_elt (ary, elem_nchars, i); |
2427 | ||
14869f28 | 2428 | if (r) |
2429 | /* Don't VERIFY_CONSTANT here. */ | |
2430 | return r; | |
09b42213 | 2431 | |
14869f28 | 2432 | /* Otherwise the element doesn't have a value yet. */ |
09b42213 | 2433 | } |
aed8dc7f | 2434 | |
14869f28 | 2435 | /* Not found. */ |
2436 | ||
2437 | if (TREE_CODE (ary) == CONSTRUCTOR | |
2438 | && CONSTRUCTOR_NO_IMPLICIT_ZERO (ary)) | |
09b42213 | 2439 | { |
14869f28 | 2440 | /* 'ary' is part of the aggregate initializer we're currently |
2441 | building; if there's no initializer for this element yet, | |
2442 | that's an error. */ | |
2443 | if (!ctx->quiet) | |
2444 | error ("accessing uninitialized array element"); | |
2445 | *non_constant_p = true; | |
2446 | return t; | |
09b42213 | 2447 | } |
14869f28 | 2448 | |
2449 | /* If it's within the array bounds but doesn't have an explicit | |
2450 | initializer, it's value-initialized. */ | |
2451 | tree val = build_value_init (elem_type, tf_warning_or_error); | |
2452 | return cxx_eval_constant_expression (ctx, val, lval, non_constant_p, | |
2453 | overflow_p); | |
09b42213 | 2454 | } |
2455 | ||
2456 | /* Subroutine of cxx_eval_constant_expression. | |
2457 | Attempt to reduce a field access of a value of class type. */ | |
2458 | ||
2459 | static tree | |
cf72f34d | 2460 | cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2461 | bool lval, |
09b42213 | 2462 | bool *non_constant_p, bool *overflow_p) |
2463 | { | |
2464 | unsigned HOST_WIDE_INT i; | |
2465 | tree field; | |
2466 | tree value; | |
2467 | tree part = TREE_OPERAND (t, 1); | |
2468 | tree orig_whole = TREE_OPERAND (t, 0); | |
cf72f34d | 2469 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2470 | lval, |
b2a43197 | 2471 | non_constant_p, overflow_p); |
7ab20d7c | 2472 | if (INDIRECT_REF_P (whole) |
cb768824 | 2473 | && integer_zerop (TREE_OPERAND (whole, 0)) |
2474 | && !ctx->quiet) | |
2475 | error ("dereferencing a null pointer in %qE", orig_whole); | |
2476 | ||
f16ed232 | 2477 | if (TREE_CODE (whole) == PTRMEM_CST) |
2478 | whole = cplus_expand_constant (whole); | |
09b42213 | 2479 | if (whole == orig_whole) |
2480 | return t; | |
1227ba74 | 2481 | if (lval) |
09b42213 | 2482 | return fold_build3 (COMPONENT_REF, TREE_TYPE (t), |
2483 | whole, part, NULL_TREE); | |
2484 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2485 | CONSTRUCTOR. */ | |
2486 | if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR) | |
2487 | { | |
f83e6885 | 2488 | if (!ctx->quiet) |
09b42213 | 2489 | error ("%qE is not a constant expression", orig_whole); |
2490 | *non_constant_p = true; | |
2491 | } | |
2492 | if (DECL_MUTABLE_P (part)) | |
2493 | { | |
f83e6885 | 2494 | if (!ctx->quiet) |
09b42213 | 2495 | error ("mutable %qD is not usable in a constant expression", part); |
2496 | *non_constant_p = true; | |
2497 | } | |
2498 | if (*non_constant_p) | |
2499 | return t; | |
a4360e57 | 2500 | bool pmf = TYPE_PTRMEMFUNC_P (TREE_TYPE (whole)); |
09b42213 | 2501 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) |
2502 | { | |
a4360e57 | 2503 | /* Use name match for PMF fields, as a variant will have a |
2504 | different FIELD_DECL with a different type. */ | |
2505 | if (pmf ? DECL_NAME (field) == DECL_NAME (part) | |
2506 | : field == part) | |
9c96033c | 2507 | { |
2508 | if (value) | |
2509 | return value; | |
2510 | else | |
2511 | /* We're in the middle of initializing it. */ | |
2512 | break; | |
2513 | } | |
09b42213 | 2514 | } |
2515 | if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE | |
2516 | && CONSTRUCTOR_NELTS (whole) > 0) | |
2517 | { | |
2518 | /* DR 1188 says we don't have to deal with this. */ | |
f83e6885 | 2519 | if (!ctx->quiet) |
09b42213 | 2520 | error ("accessing %qD member instead of initialized %qD member in " |
2521 | "constant expression", part, CONSTRUCTOR_ELT (whole, 0)->index); | |
2522 | *non_constant_p = true; | |
2523 | return t; | |
2524 | } | |
2525 | ||
f894a056 | 2526 | /* We only create a CONSTRUCTOR for a subobject when we modify it, so empty |
2527 | classes never get represented; throw together a value now. */ | |
2528 | if (is_really_empty_class (TREE_TYPE (t))) | |
2529 | return build_constructor (TREE_TYPE (t), NULL); | |
2530 | ||
a4360e57 | 2531 | gcc_assert (DECL_CONTEXT (part) == TYPE_MAIN_VARIANT (TREE_TYPE (whole))); |
2532 | ||
f894a056 | 2533 | if (CONSTRUCTOR_NO_IMPLICIT_ZERO (whole)) |
cf72f34d | 2534 | { |
2535 | /* 'whole' is part of the aggregate initializer we're currently | |
2536 | building; if there's no initializer for this member yet, that's an | |
f894a056 | 2537 | error. */ |
f83e6885 | 2538 | if (!ctx->quiet) |
cf72f34d | 2539 | error ("accessing uninitialized member %qD", part); |
2540 | *non_constant_p = true; | |
2541 | return t; | |
2542 | } | |
2543 | ||
09b42213 | 2544 | /* If there's no explicit init for this field, it's value-initialized. */ |
2545 | value = build_value_init (TREE_TYPE (t), tf_warning_or_error); | |
cf72f34d | 2546 | return cxx_eval_constant_expression (ctx, value, |
1227ba74 | 2547 | lval, |
b2a43197 | 2548 | non_constant_p, overflow_p); |
09b42213 | 2549 | } |
2550 | ||
2551 | /* Subroutine of cxx_eval_constant_expression. | |
2552 | Attempt to reduce a field access of a value of class type that is | |
2553 | expressed as a BIT_FIELD_REF. */ | |
2554 | ||
2555 | static tree | |
cf72f34d | 2556 | cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2557 | bool lval, |
09b42213 | 2558 | bool *non_constant_p, bool *overflow_p) |
2559 | { | |
2560 | tree orig_whole = TREE_OPERAND (t, 0); | |
2561 | tree retval, fldval, utype, mask; | |
2562 | bool fld_seen = false; | |
2563 | HOST_WIDE_INT istart, isize; | |
cf72f34d | 2564 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2565 | lval, |
b2a43197 | 2566 | non_constant_p, overflow_p); |
09b42213 | 2567 | tree start, field, value; |
2568 | unsigned HOST_WIDE_INT i; | |
2569 | ||
2570 | if (whole == orig_whole) | |
2571 | return t; | |
2572 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2573 | CONSTRUCTOR. */ | |
2574 | if (!*non_constant_p | |
2575 | && TREE_CODE (whole) != VECTOR_CST | |
2576 | && TREE_CODE (whole) != CONSTRUCTOR) | |
2577 | { | |
f83e6885 | 2578 | if (!ctx->quiet) |
09b42213 | 2579 | error ("%qE is not a constant expression", orig_whole); |
2580 | *non_constant_p = true; | |
2581 | } | |
2582 | if (*non_constant_p) | |
2583 | return t; | |
2584 | ||
2585 | if (TREE_CODE (whole) == VECTOR_CST) | |
2586 | return fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole, | |
2587 | TREE_OPERAND (t, 1), TREE_OPERAND (t, 2)); | |
2588 | ||
2589 | start = TREE_OPERAND (t, 2); | |
2590 | istart = tree_to_shwi (start); | |
2591 | isize = tree_to_shwi (TREE_OPERAND (t, 1)); | |
2592 | utype = TREE_TYPE (t); | |
2593 | if (!TYPE_UNSIGNED (utype)) | |
2594 | utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1); | |
2595 | retval = build_int_cst (utype, 0); | |
2596 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
2597 | { | |
2598 | tree bitpos = bit_position (field); | |
2599 | if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1)) | |
2600 | return value; | |
2601 | if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE | |
2602 | && TREE_CODE (value) == INTEGER_CST | |
2603 | && tree_fits_shwi_p (bitpos) | |
2604 | && tree_fits_shwi_p (DECL_SIZE (field))) | |
2605 | { | |
2606 | HOST_WIDE_INT bit = tree_to_shwi (bitpos); | |
2607 | HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field)); | |
2608 | HOST_WIDE_INT shift; | |
2609 | if (bit >= istart && bit + sz <= istart + isize) | |
2610 | { | |
2611 | fldval = fold_convert (utype, value); | |
2612 | mask = build_int_cst_type (utype, -1); | |
2613 | mask = fold_build2 (LSHIFT_EXPR, utype, mask, | |
2614 | size_int (TYPE_PRECISION (utype) - sz)); | |
2615 | mask = fold_build2 (RSHIFT_EXPR, utype, mask, | |
2616 | size_int (TYPE_PRECISION (utype) - sz)); | |
2617 | fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask); | |
2618 | shift = bit - istart; | |
2619 | if (BYTES_BIG_ENDIAN) | |
2620 | shift = TYPE_PRECISION (utype) - shift - sz; | |
2621 | fldval = fold_build2 (LSHIFT_EXPR, utype, fldval, | |
2622 | size_int (shift)); | |
2623 | retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval); | |
2624 | fld_seen = true; | |
2625 | } | |
2626 | } | |
2627 | } | |
2628 | if (fld_seen) | |
2629 | return fold_convert (TREE_TYPE (t), retval); | |
2630 | gcc_unreachable (); | |
2631 | return error_mark_node; | |
2632 | } | |
2633 | ||
2634 | /* Subroutine of cxx_eval_constant_expression. | |
2635 | Evaluate a short-circuited logical expression T in the context | |
2636 | of a given constexpr CALL. BAILOUT_VALUE is the value for | |
2637 | early return. CONTINUE_VALUE is used here purely for | |
2638 | sanity check purposes. */ | |
2639 | ||
2640 | static tree | |
cf72f34d | 2641 | cxx_eval_logical_expression (const constexpr_ctx *ctx, tree t, |
09b42213 | 2642 | tree bailout_value, tree continue_value, |
1227ba74 | 2643 | bool lval, |
09b42213 | 2644 | bool *non_constant_p, bool *overflow_p) |
2645 | { | |
2646 | tree r; | |
cf72f34d | 2647 | tree lhs = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 2648 | lval, |
b2a43197 | 2649 | non_constant_p, overflow_p); |
09b42213 | 2650 | VERIFY_CONSTANT (lhs); |
2651 | if (tree_int_cst_equal (lhs, bailout_value)) | |
2652 | return lhs; | |
2653 | gcc_assert (tree_int_cst_equal (lhs, continue_value)); | |
cf72f34d | 2654 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2655 | lval, non_constant_p, |
b2a43197 | 2656 | overflow_p); |
09b42213 | 2657 | VERIFY_CONSTANT (r); |
2658 | return r; | |
2659 | } | |
2660 | ||
2661 | /* REF is a COMPONENT_REF designating a particular field. V is a vector of | |
2662 | CONSTRUCTOR elements to initialize (part of) an object containing that | |
2663 | field. Return a pointer to the constructor_elt corresponding to the | |
2664 | initialization of the field. */ | |
2665 | ||
2666 | static constructor_elt * | |
2667 | base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref) | |
2668 | { | |
2669 | tree aggr = TREE_OPERAND (ref, 0); | |
2670 | tree field = TREE_OPERAND (ref, 1); | |
2671 | HOST_WIDE_INT i; | |
2672 | constructor_elt *ce; | |
2673 | ||
2674 | gcc_assert (TREE_CODE (ref) == COMPONENT_REF); | |
2675 | ||
2676 | if (TREE_CODE (aggr) == COMPONENT_REF) | |
2677 | { | |
2678 | constructor_elt *base_ce | |
2679 | = base_field_constructor_elt (v, aggr); | |
2680 | v = CONSTRUCTOR_ELTS (base_ce->value); | |
2681 | } | |
2682 | ||
2683 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2684 | if (ce->index == field) | |
2685 | return ce; | |
2686 | ||
2687 | gcc_unreachable (); | |
2688 | return NULL; | |
2689 | } | |
2690 | ||
cf72f34d | 2691 | /* Some of the expressions fed to the constexpr mechanism are calls to |
2692 | constructors, which have type void. In that case, return the type being | |
2693 | initialized by the constructor. */ | |
2694 | ||
2695 | static tree | |
2696 | initialized_type (tree t) | |
2697 | { | |
2698 | if (TYPE_P (t)) | |
2699 | return t; | |
2700 | tree type = cv_unqualified (TREE_TYPE (t)); | |
2701 | if (TREE_CODE (t) == CALL_EXPR || TREE_CODE (t) == AGGR_INIT_EXPR) | |
2702 | { | |
2703 | /* A constructor call has void type, so we need to look deeper. */ | |
2704 | tree fn = get_function_named_in_call (t); | |
2705 | if (fn && TREE_CODE (fn) == FUNCTION_DECL | |
2706 | && DECL_CXX_CONSTRUCTOR_P (fn)) | |
2707 | type = DECL_CONTEXT (fn); | |
2708 | } | |
2709 | return type; | |
2710 | } | |
2711 | ||
2712 | /* We're about to initialize element INDEX of an array or class from VALUE. | |
2713 | Set up NEW_CTX appropriately by adjusting .object to refer to the | |
2714 | subobject and creating a new CONSTRUCTOR if the element is itself | |
2715 | a class or array. */ | |
2716 | ||
2717 | static void | |
2718 | init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, | |
2719 | tree index, tree &value) | |
2720 | { | |
2721 | new_ctx = *ctx; | |
2722 | ||
2723 | if (index && TREE_CODE (index) != INTEGER_CST | |
2724 | && TREE_CODE (index) != FIELD_DECL) | |
2725 | /* This won't have an element in the new CONSTRUCTOR. */ | |
2726 | return; | |
2727 | ||
2728 | tree type = initialized_type (value); | |
2729 | if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) | |
2730 | /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ | |
2731 | return; | |
2732 | ||
2733 | /* The sub-aggregate initializer might contain a placeholder; | |
2734 | update object to refer to the subobject and ctor to refer to | |
2735 | the (newly created) sub-initializer. */ | |
2736 | if (ctx->object) | |
2737 | new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); | |
2738 | tree elt = build_constructor (type, NULL); | |
2739 | CONSTRUCTOR_NO_IMPLICIT_ZERO (elt) = true; | |
2740 | new_ctx.ctor = elt; | |
2741 | ||
2742 | if (TREE_CODE (value) == TARGET_EXPR) | |
2743 | /* Avoid creating another CONSTRUCTOR when we expand the TARGET_EXPR. */ | |
2744 | value = TARGET_EXPR_INITIAL (value); | |
2745 | } | |
2746 | ||
2747 | /* We're about to process an initializer for a class or array TYPE. Make | |
2748 | sure that CTX is set up appropriately. */ | |
2749 | ||
2750 | static void | |
2751 | verify_ctor_sanity (const constexpr_ctx *ctx, tree type) | |
2752 | { | |
2753 | /* We don't bother building a ctor for an empty base subobject. */ | |
2754 | if (is_empty_class (type)) | |
2755 | return; | |
2756 | ||
2757 | /* We're in the middle of an initializer that might involve placeholders; | |
2758 | our caller should have created a CONSTRUCTOR for us to put the | |
2759 | initializer into. We will either return that constructor or T. */ | |
2760 | gcc_assert (ctx->ctor); | |
2761 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2762 | (type, TREE_TYPE (ctx->ctor))); | |
bbf58224 | 2763 | /* We used to check that ctx->ctor was empty, but that isn't the case when |
2764 | the object is zero-initialized before calling the constructor. */ | |
cf72f34d | 2765 | if (ctx->object) |
d9751a3c | 2766 | { |
2767 | tree otype = TREE_TYPE (ctx->object); | |
2768 | gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, otype) | |
2769 | /* Handle flexible array members. */ | |
2770 | || (TREE_CODE (otype) == ARRAY_TYPE | |
2771 | && TYPE_DOMAIN (otype) == NULL_TREE | |
2772 | && TREE_CODE (type) == ARRAY_TYPE | |
2773 | && (same_type_ignoring_top_level_qualifiers_p | |
2774 | (TREE_TYPE (type), TREE_TYPE (otype))))); | |
2775 | } | |
cf72f34d | 2776 | gcc_assert (!ctx->object || !DECL_P (ctx->object) |
2777 | || *(ctx->values->get (ctx->object)) == ctx->ctor); | |
2778 | } | |
2779 | ||
09b42213 | 2780 | /* Subroutine of cxx_eval_constant_expression. |
2781 | The expression tree T denotes a C-style array or a C-style | |
2782 | aggregate. Reduce it to a constant expression. */ | |
2783 | ||
2784 | static tree | |
cf72f34d | 2785 | cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2786 | bool lval, |
09b42213 | 2787 | bool *non_constant_p, bool *overflow_p) |
2788 | { | |
2789 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
09b42213 | 2790 | bool changed = false; |
2791 | gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t)); | |
68464393 | 2792 | tree type = TREE_TYPE (t); |
cf72f34d | 2793 | |
68464393 | 2794 | constexpr_ctx new_ctx; |
d2dd85e3 | 2795 | if (TYPE_PTRMEMFUNC_P (type) || VECTOR_TYPE_P (type)) |
68464393 | 2796 | { |
d2dd85e3 | 2797 | /* We don't really need the ctx->ctor business for a PMF or |
2798 | vector, but it's simpler to use the same code. */ | |
68464393 | 2799 | new_ctx = *ctx; |
2800 | new_ctx.ctor = build_constructor (type, NULL); | |
2801 | new_ctx.object = NULL_TREE; | |
2802 | ctx = &new_ctx; | |
2803 | }; | |
2804 | verify_ctor_sanity (ctx, type); | |
cf72f34d | 2805 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); |
2806 | vec_alloc (*p, vec_safe_length (v)); | |
2807 | ||
58b0f9ce | 2808 | unsigned i; |
2809 | tree index, value; | |
2810 | bool constant_p = true; | |
2811 | bool side_effects_p = false; | |
cf72f34d | 2812 | FOR_EACH_CONSTRUCTOR_ELT (v, i, index, value) |
09b42213 | 2813 | { |
5ae773e4 | 2814 | tree orig_value = value; |
cf72f34d | 2815 | init_subob_ctx (ctx, new_ctx, index, value); |
2816 | if (new_ctx.ctor != ctx->ctor) | |
2817 | /* If we built a new CONSTRUCTOR, attach it now so that other | |
2818 | initializers can refer to it. */ | |
2819 | CONSTRUCTOR_APPEND_ELT (*p, index, new_ctx.ctor); | |
2820 | tree elt = cxx_eval_constant_expression (&new_ctx, value, | |
1227ba74 | 2821 | lval, |
b2a43197 | 2822 | non_constant_p, overflow_p); |
09b42213 | 2823 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 2824 | if (ctx->quiet && *non_constant_p) |
cf72f34d | 2825 | break; |
5ae773e4 | 2826 | if (elt != orig_value) |
09b42213 | 2827 | changed = true; |
58b0f9ce | 2828 | |
2829 | if (!TREE_CONSTANT (elt)) | |
2830 | constant_p = false; | |
2831 | if (TREE_SIDE_EFFECTS (elt)) | |
2832 | side_effects_p = true; | |
cf72f34d | 2833 | if (index && TREE_CODE (index) == COMPONENT_REF) |
09b42213 | 2834 | { |
2835 | /* This is an initialization of a vfield inside a base | |
2836 | subaggregate that we already initialized; push this | |
2837 | initialization into the previous initialization. */ | |
cf72f34d | 2838 | constructor_elt *inner = base_field_constructor_elt (*p, index); |
09b42213 | 2839 | inner->value = elt; |
cf72f34d | 2840 | changed = true; |
09b42213 | 2841 | } |
cf72f34d | 2842 | else if (index |
2843 | && (TREE_CODE (index) == NOP_EXPR | |
2844 | || TREE_CODE (index) == POINTER_PLUS_EXPR)) | |
09b42213 | 2845 | { |
2846 | /* This is an initializer for an empty base; now that we've | |
2847 | checked that it's constant, we can ignore it. */ | |
cf72f34d | 2848 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (index)))); |
2849 | changed = true; | |
2850 | } | |
2851 | else if (new_ctx.ctor != ctx->ctor) | |
2852 | { | |
2853 | /* We appended this element above; update the value. */ | |
2854 | gcc_assert ((*p)->last().index == index); | |
2855 | (*p)->last().value = elt; | |
09b42213 | 2856 | } |
2857 | else | |
cf72f34d | 2858 | CONSTRUCTOR_APPEND_ELT (*p, index, elt); |
09b42213 | 2859 | } |
2860 | if (*non_constant_p || !changed) | |
cf72f34d | 2861 | return t; |
2862 | t = ctx->ctor; | |
2863 | /* We're done building this CONSTRUCTOR, so now we can interpret an | |
2864 | element without an explicit initializer as value-initialized. */ | |
2865 | CONSTRUCTOR_NO_IMPLICIT_ZERO (t) = false; | |
58b0f9ce | 2866 | TREE_CONSTANT (t) = constant_p; |
2867 | TREE_SIDE_EFFECTS (t) = side_effects_p; | |
68464393 | 2868 | if (VECTOR_TYPE_P (type)) |
09b42213 | 2869 | t = fold (t); |
2870 | return t; | |
2871 | } | |
2872 | ||
2873 | /* Subroutine of cxx_eval_constant_expression. | |
2874 | The expression tree T is a VEC_INIT_EXPR which denotes the desired | |
2875 | initialization of a non-static data member of array type. Reduce it to a | |
2876 | CONSTRUCTOR. | |
2877 | ||
2878 | Note that apart from value-initialization (when VALUE_INIT is true), | |
2879 | this is only intended to support value-initialization and the | |
2880 | initializations done by defaulted constructors for classes with | |
2881 | non-static data members of array type. In this case, VEC_INIT_EXPR_INIT | |
2882 | will either be NULL_TREE for the default constructor, or a COMPONENT_REF | |
2883 | for the copy/move constructor. */ | |
2884 | ||
2885 | static tree | |
cf72f34d | 2886 | cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, |
1227ba74 | 2887 | bool value_init, bool lval, |
09b42213 | 2888 | bool *non_constant_p, bool *overflow_p) |
2889 | { | |
2890 | tree elttype = TREE_TYPE (atype); | |
3e520b97 | 2891 | unsigned HOST_WIDE_INT max = tree_to_uhwi (array_type_nelts_top (atype)); |
cf72f34d | 2892 | verify_ctor_sanity (ctx, atype); |
2893 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
09b42213 | 2894 | bool pre_init = false; |
3e520b97 | 2895 | unsigned HOST_WIDE_INT i; |
09b42213 | 2896 | |
2897 | /* For the default constructor, build up a call to the default | |
2898 | constructor of the element type. We only need to handle class types | |
2899 | here, as for a constructor to be constexpr, all members must be | |
2900 | initialized, which for a defaulted default constructor means they must | |
2901 | be of a class type with a constexpr default constructor. */ | |
2902 | if (TREE_CODE (elttype) == ARRAY_TYPE) | |
2903 | /* We only do this at the lowest level. */; | |
2904 | else if (value_init) | |
2905 | { | |
2906 | init = build_value_init (elttype, tf_warning_or_error); | |
09b42213 | 2907 | pre_init = true; |
2908 | } | |
2909 | else if (!init) | |
2910 | { | |
2911 | vec<tree, va_gc> *argvec = make_tree_vector (); | |
2912 | init = build_special_member_call (NULL_TREE, complete_ctor_identifier, | |
2913 | &argvec, elttype, LOOKUP_NORMAL, | |
2914 | tf_warning_or_error); | |
2915 | release_tree_vector (argvec); | |
9c96033c | 2916 | init = build_aggr_init_expr (TREE_TYPE (init), init); |
09b42213 | 2917 | pre_init = true; |
2918 | } | |
2919 | ||
3e520b97 | 2920 | for (i = 0; i < max; ++i) |
09b42213 | 2921 | { |
2922 | tree idx = build_int_cst (size_type_node, i); | |
2923 | tree eltinit; | |
d9377ad5 | 2924 | bool reuse = false; |
cf72f34d | 2925 | constexpr_ctx new_ctx; |
2926 | init_subob_ctx (ctx, new_ctx, idx, pre_init ? init : elttype); | |
2927 | if (new_ctx.ctor != ctx->ctor) | |
2928 | CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor); | |
09b42213 | 2929 | if (TREE_CODE (elttype) == ARRAY_TYPE) |
2930 | { | |
2931 | /* A multidimensional array; recurse. */ | |
2932 | if (value_init || init == NULL_TREE) | |
d9377ad5 | 2933 | { |
2934 | eltinit = NULL_TREE; | |
2935 | reuse = i == 0; | |
2936 | } | |
09b42213 | 2937 | else |
2938 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2939 | tf_warning_or_error); | |
cf72f34d | 2940 | eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, value_init, |
1227ba74 | 2941 | lval, |
09b42213 | 2942 | non_constant_p, overflow_p); |
2943 | } | |
2944 | else if (pre_init) | |
2945 | { | |
2946 | /* Initializing an element using value or default initialization | |
2947 | we just pre-built above. */ | |
d9377ad5 | 2948 | eltinit = cxx_eval_constant_expression (&new_ctx, init, lval, |
2949 | non_constant_p, overflow_p); | |
2950 | reuse = i == 0; | |
09b42213 | 2951 | } |
2952 | else | |
2953 | { | |
2954 | /* Copying an element. */ | |
2955 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2956 | (atype, TREE_TYPE (init))); | |
2957 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2958 | tf_warning_or_error); | |
18bede74 | 2959 | if (!lvalue_p (init)) |
09b42213 | 2960 | eltinit = move (eltinit); |
2961 | eltinit = force_rvalue (eltinit, tf_warning_or_error); | |
eb7c25cc | 2962 | eltinit = cxx_eval_constant_expression (&new_ctx, eltinit, lval, |
2963 | non_constant_p, overflow_p); | |
09b42213 | 2964 | } |
f83e6885 | 2965 | if (*non_constant_p && !ctx->quiet) |
cf72f34d | 2966 | break; |
2967 | if (new_ctx.ctor != ctx->ctor) | |
2968 | { | |
2969 | /* We appended this element above; update the value. */ | |
2970 | gcc_assert ((*p)->last().index == idx); | |
2971 | (*p)->last().value = eltinit; | |
2972 | } | |
2973 | else | |
2974 | CONSTRUCTOR_APPEND_ELT (*p, idx, eltinit); | |
d9377ad5 | 2975 | /* Reuse the result of cxx_eval_constant_expression call |
eb7c25cc | 2976 | from the first iteration to all others if it is a constant |
2977 | initializer that doesn't require relocations. */ | |
d9377ad5 | 2978 | if (reuse |
2979 | && max > 1 | |
eb7c25cc | 2980 | && (eltinit == NULL_TREE |
2981 | || (initializer_constant_valid_p (eltinit, TREE_TYPE (eltinit)) | |
2982 | == null_pointer_node))) | |
d9377ad5 | 2983 | { |
2984 | if (new_ctx.ctor != ctx->ctor) | |
2985 | eltinit = new_ctx.ctor; | |
228a2cd8 | 2986 | tree range = build2 (RANGE_EXPR, size_type_node, |
2987 | build_int_cst (size_type_node, 1), | |
2988 | build_int_cst (size_type_node, max - 1)); | |
2989 | CONSTRUCTOR_APPEND_ELT (*p, range, unshare_constructor (eltinit)); | |
d9377ad5 | 2990 | break; |
2991 | } | |
228a2cd8 | 2992 | else if (i == 0) |
2993 | vec_safe_reserve (*p, max); | |
09b42213 | 2994 | } |
2995 | ||
2996 | if (!*non_constant_p) | |
2997 | { | |
cf72f34d | 2998 | init = ctx->ctor; |
2999 | CONSTRUCTOR_NO_IMPLICIT_ZERO (init) = false; | |
09b42213 | 3000 | } |
09b42213 | 3001 | return init; |
3002 | } | |
3003 | ||
3004 | static tree | |
cf72f34d | 3005 | cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3006 | bool lval, |
09b42213 | 3007 | bool *non_constant_p, bool *overflow_p) |
3008 | { | |
3009 | tree atype = TREE_TYPE (t); | |
3010 | tree init = VEC_INIT_EXPR_INIT (t); | |
cf72f34d | 3011 | tree r = cxx_eval_vec_init_1 (ctx, atype, init, |
09b42213 | 3012 | VEC_INIT_EXPR_VALUE_INIT (t), |
1227ba74 | 3013 | lval, non_constant_p, overflow_p); |
09b42213 | 3014 | if (*non_constant_p) |
3015 | return t; | |
3016 | else | |
3017 | return r; | |
3018 | } | |
3019 | ||
3020 | /* A less strict version of fold_indirect_ref_1, which requires cv-quals to | |
3021 | match. We want to be less strict for simple *& folding; if we have a | |
3022 | non-const temporary that we access through a const pointer, that should | |
3023 | work. We handle this here rather than change fold_indirect_ref_1 | |
3024 | because we're dealing with things like ADDR_EXPR of INTEGER_CST which | |
3025 | don't really make sense outside of constant expression evaluation. Also | |
3026 | we want to allow folding to COMPONENT_REF, which could cause trouble | |
3027 | with TBAA in fold_indirect_ref_1. | |
3028 | ||
3029 | Try to keep this function synced with fold_indirect_ref_1. */ | |
3030 | ||
3031 | static tree | |
3032 | cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) | |
3033 | { | |
7d8e655d | 3034 | tree sub = op0; |
3035 | tree subtype; | |
3036 | poly_uint64 const_op01; | |
09b42213 | 3037 | |
09b42213 | 3038 | STRIP_NOPS (sub); |
3039 | subtype = TREE_TYPE (sub); | |
3040 | if (!POINTER_TYPE_P (subtype)) | |
3041 | return NULL_TREE; | |
3042 | ||
3043 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3044 | { | |
3045 | tree op = TREE_OPERAND (sub, 0); | |
3046 | tree optype = TREE_TYPE (op); | |
3047 | ||
3048 | /* *&CONST_DECL -> to the value of the const decl. */ | |
3049 | if (TREE_CODE (op) == CONST_DECL) | |
3050 | return DECL_INITIAL (op); | |
3051 | /* *&p => p; make sure to handle *&"str"[cst] here. */ | |
c4118b0c | 3052 | if (same_type_ignoring_top_level_qualifiers_p (optype, type) |
3053 | /* Also handle the case where the desired type is an array of unknown | |
3054 | bounds because the variable has had its bounds deduced since the | |
3055 | ADDR_EXPR was created. */ | |
3056 | || (TREE_CODE (type) == ARRAY_TYPE | |
3057 | && TREE_CODE (optype) == ARRAY_TYPE | |
3058 | && TYPE_DOMAIN (type) == NULL_TREE | |
3059 | && same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (optype), | |
3060 | TREE_TYPE (type)))) | |
09b42213 | 3061 | { |
3062 | tree fop = fold_read_from_constant_string (op); | |
3063 | if (fop) | |
3064 | return fop; | |
3065 | else | |
3066 | return op; | |
3067 | } | |
3068 | /* *(foo *)&fooarray => fooarray[0] */ | |
3069 | else if (TREE_CODE (optype) == ARRAY_TYPE | |
3070 | && (same_type_ignoring_top_level_qualifiers_p | |
3071 | (type, TREE_TYPE (optype)))) | |
3072 | { | |
3073 | tree type_domain = TYPE_DOMAIN (optype); | |
3074 | tree min_val = size_zero_node; | |
3075 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3076 | min_val = TYPE_MIN_VALUE (type_domain); | |
3077 | return build4_loc (loc, ARRAY_REF, type, op, min_val, | |
3078 | NULL_TREE, NULL_TREE); | |
3079 | } | |
3080 | /* *(foo *)&complexfoo => __real__ complexfoo */ | |
3081 | else if (TREE_CODE (optype) == COMPLEX_TYPE | |
3082 | && (same_type_ignoring_top_level_qualifiers_p | |
3083 | (type, TREE_TYPE (optype)))) | |
3084 | return fold_build1_loc (loc, REALPART_EXPR, type, op); | |
3085 | /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3086 | else if (VECTOR_TYPE_P (optype) |
09b42213 | 3087 | && (same_type_ignoring_top_level_qualifiers_p |
3088 | (type, TREE_TYPE (optype)))) | |
3089 | { | |
3090 | tree part_width = TYPE_SIZE (type); | |
3091 | tree index = bitsize_int (0); | |
7d8e655d | 3092 | return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, |
3093 | index); | |
09b42213 | 3094 | } |
3095 | /* Also handle conversion to an empty base class, which | |
3096 | is represented with a NOP_EXPR. */ | |
3097 | else if (is_empty_class (type) | |
3098 | && CLASS_TYPE_P (optype) | |
3099 | && DERIVED_FROM_P (type, optype)) | |
3100 | { | |
3101 | *empty_base = true; | |
3102 | return op; | |
3103 | } | |
3104 | /* *(foo *)&struct_with_foo_field => COMPONENT_REF */ | |
3105 | else if (RECORD_OR_UNION_TYPE_P (optype)) | |
3106 | { | |
3107 | tree field = TYPE_FIELDS (optype); | |
3108 | for (; field; field = DECL_CHAIN (field)) | |
3109 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3110 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3111 | && integer_zerop (byte_position (field)) |
3112 | && (same_type_ignoring_top_level_qualifiers_p | |
3113 | (TREE_TYPE (field), type))) | |
a48667ee | 3114 | return fold_build3 (COMPONENT_REF, type, op, field, NULL_TREE); |
09b42213 | 3115 | } |
3116 | } | |
3117 | else if (TREE_CODE (sub) == POINTER_PLUS_EXPR | |
7d8e655d | 3118 | && poly_int_tree_p (TREE_OPERAND (sub, 1), &const_op01)) |
09b42213 | 3119 | { |
3120 | tree op00 = TREE_OPERAND (sub, 0); | |
3121 | tree op01 = TREE_OPERAND (sub, 1); | |
3122 | ||
3123 | STRIP_NOPS (op00); | |
3124 | if (TREE_CODE (op00) == ADDR_EXPR) | |
3125 | { | |
3126 | tree op00type; | |
3127 | op00 = TREE_OPERAND (op00, 0); | |
3128 | op00type = TREE_TYPE (op00); | |
3129 | ||
3130 | /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3131 | if (VECTOR_TYPE_P (op00type) |
7d8e655d | 3132 | && same_type_ignoring_top_level_qualifiers_p |
3133 | (type, TREE_TYPE (op00type)) | |
3134 | /* POINTER_PLUS_EXPR second operand is sizetype, unsigned, | |
3135 | but we want to treat offsets with MSB set as negative. | |
3136 | For the code below negative offsets are invalid and | |
3137 | TYPE_SIZE of the element is something unsigned, so | |
3138 | check whether op01 fits into poly_int64, which implies | |
3139 | it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and | |
3140 | then just use poly_uint64 because we want to treat the | |
3141 | value as unsigned. */ | |
3142 | && tree_fits_poly_int64_p (op01)) | |
09b42213 | 3143 | { |
09b42213 | 3144 | tree part_width = TYPE_SIZE (type); |
7d8e655d | 3145 | poly_uint64 max_offset |
3146 | = (tree_to_uhwi (part_width) / BITS_PER_UNIT | |
3147 | * TYPE_VECTOR_SUBPARTS (op00type)); | |
3148 | if (known_lt (const_op01, max_offset)) | |
3149 | { | |
3150 | tree index = bitsize_int (const_op01 * BITS_PER_UNIT); | |
3151 | return fold_build3_loc (loc, | |
3152 | BIT_FIELD_REF, type, op00, | |
3153 | part_width, index); | |
3154 | } | |
09b42213 | 3155 | } |
3156 | /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ | |
3157 | else if (TREE_CODE (op00type) == COMPLEX_TYPE | |
3158 | && (same_type_ignoring_top_level_qualifiers_p | |
3159 | (type, TREE_TYPE (op00type)))) | |
3160 | { | |
7d8e655d | 3161 | if (known_eq (wi::to_poly_offset (TYPE_SIZE_UNIT (type)), |
3162 | const_op01)) | |
09b42213 | 3163 | return fold_build1_loc (loc, IMAGPART_EXPR, type, op00); |
3164 | } | |
3165 | /* ((foo *)&fooarray)[1] => fooarray[1] */ | |
3166 | else if (TREE_CODE (op00type) == ARRAY_TYPE | |
3167 | && (same_type_ignoring_top_level_qualifiers_p | |
3168 | (type, TREE_TYPE (op00type)))) | |
3169 | { | |
3170 | tree type_domain = TYPE_DOMAIN (op00type); | |
3171 | tree min_val = size_zero_node; | |
3172 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3173 | min_val = TYPE_MIN_VALUE (type_domain); | |
53fa96c0 | 3174 | offset_int off = wi::to_offset (op01); |
3175 | offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type)); | |
3176 | offset_int remainder; | |
3177 | off = wi::divmod_trunc (off, el_sz, SIGNED, &remainder); | |
3178 | if (remainder == 0 && TREE_CODE (min_val) == INTEGER_CST) | |
3179 | { | |
3180 | off = off + wi::to_offset (min_val); | |
3181 | op01 = wide_int_to_tree (sizetype, off); | |
3182 | return build4_loc (loc, ARRAY_REF, type, op00, op01, | |
3183 | NULL_TREE, NULL_TREE); | |
3184 | } | |
09b42213 | 3185 | } |
3186 | /* Also handle conversion to an empty base class, which | |
3187 | is represented with a NOP_EXPR. */ | |
3188 | else if (is_empty_class (type) | |
3189 | && CLASS_TYPE_P (op00type) | |
3190 | && DERIVED_FROM_P (type, op00type)) | |
3191 | { | |
3192 | *empty_base = true; | |
3193 | return op00; | |
3194 | } | |
3195 | /* ((foo *)&struct_with_foo_field)[1] => COMPONENT_REF */ | |
3196 | else if (RECORD_OR_UNION_TYPE_P (op00type)) | |
3197 | { | |
3198 | tree field = TYPE_FIELDS (op00type); | |
3199 | for (; field; field = DECL_CHAIN (field)) | |
3200 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3201 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3202 | && tree_int_cst_equal (byte_position (field), op01) |
3203 | && (same_type_ignoring_top_level_qualifiers_p | |
3204 | (TREE_TYPE (field), type))) | |
a48667ee | 3205 | return fold_build3 (COMPONENT_REF, type, op00, |
3206 | field, NULL_TREE); | |
09b42213 | 3207 | } |
3208 | } | |
3209 | } | |
3210 | /* *(foo *)fooarrptr => (*fooarrptr)[0] */ | |
3211 | else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE | |
3212 | && (same_type_ignoring_top_level_qualifiers_p | |
3213 | (type, TREE_TYPE (TREE_TYPE (subtype))))) | |
3214 | { | |
3215 | tree type_domain; | |
3216 | tree min_val = size_zero_node; | |
7d8e655d | 3217 | tree newsub |
3218 | = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL); | |
09b42213 | 3219 | if (newsub) |
3220 | sub = newsub; | |
3221 | else | |
3222 | sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub); | |
3223 | type_domain = TYPE_DOMAIN (TREE_TYPE (sub)); | |
3224 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3225 | min_val = TYPE_MIN_VALUE (type_domain); | |
3226 | return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE, | |
3227 | NULL_TREE); | |
3228 | } | |
3229 | ||
3230 | return NULL_TREE; | |
3231 | } | |
3232 | ||
3233 | static tree | |
cf72f34d | 3234 | cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3235 | bool lval, |
09b42213 | 3236 | bool *non_constant_p, bool *overflow_p) |
3237 | { | |
3238 | tree orig_op0 = TREE_OPERAND (t, 0); | |
09b42213 | 3239 | bool empty_base = false; |
09b42213 | 3240 | |
d2c63826 | 3241 | /* We can handle a MEM_REF like an INDIRECT_REF, if MEM_REF's second |
3242 | operand is an integer-zero. Otherwise reject the MEM_REF for now. */ | |
3243 | ||
3244 | if (TREE_CODE (t) == MEM_REF | |
3245 | && (!TREE_OPERAND (t, 1) || !integer_zerop (TREE_OPERAND (t, 1)))) | |
3246 | { | |
3247 | gcc_assert (ctx->quiet); | |
3248 | *non_constant_p = true; | |
3249 | return t; | |
3250 | } | |
3251 | ||
7e0f3388 | 3252 | /* First try to simplify it directly. */ |
3253 | tree r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), orig_op0, | |
3254 | &empty_base); | |
3255 | if (!r) | |
09b42213 | 3256 | { |
7e0f3388 | 3257 | /* If that didn't work, evaluate the operand first. */ |
3258 | tree op0 = cxx_eval_constant_expression (ctx, orig_op0, | |
3259 | /*lval*/false, non_constant_p, | |
3260 | overflow_p); | |
3261 | /* Don't VERIFY_CONSTANT here. */ | |
3262 | if (*non_constant_p) | |
3263 | return t; | |
3264 | ||
cb768824 | 3265 | if (!lval && integer_zerop (op0)) |
3266 | { | |
3267 | if (!ctx->quiet) | |
3268 | error ("dereferencing a null pointer"); | |
3269 | *non_constant_p = true; | |
3270 | return t; | |
3271 | } | |
3272 | ||
7e0f3388 | 3273 | r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), op0, |
3274 | &empty_base); | |
3275 | if (r == NULL_TREE) | |
09b42213 | 3276 | { |
3277 | /* We couldn't fold to a constant value. Make sure it's not | |
3278 | something we should have been able to fold. */ | |
7e0f3388 | 3279 | tree sub = op0; |
3280 | STRIP_NOPS (sub); | |
3281 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3282 | { | |
3283 | gcc_assert (!same_type_ignoring_top_level_qualifiers_p | |
3284 | (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t))); | |
3285 | /* DR 1188 says we don't have to deal with this. */ | |
3286 | if (!ctx->quiet) | |
3287 | error ("accessing value of %qE through a %qT glvalue in a " | |
3288 | "constant expression", build_fold_indirect_ref (sub), | |
3289 | TREE_TYPE (t)); | |
3290 | *non_constant_p = true; | |
3291 | return t; | |
3292 | } | |
3293 | ||
3294 | if (lval && op0 != orig_op0) | |
3295 | return build1 (INDIRECT_REF, TREE_TYPE (t), op0); | |
3296 | if (!lval) | |
3297 | VERIFY_CONSTANT (t); | |
09b42213 | 3298 | return t; |
3299 | } | |
3300 | } | |
3301 | ||
7e0f3388 | 3302 | r = cxx_eval_constant_expression (ctx, r, |
3303 | lval, non_constant_p, overflow_p); | |
3304 | if (*non_constant_p) | |
3305 | return t; | |
3306 | ||
ce4ffd9e | 3307 | /* If we're pulling out the value of an empty base, just return an empty |
09b42213 | 3308 | CONSTRUCTOR. */ |
1227ba74 | 3309 | if (empty_base && !lval) |
09b42213 | 3310 | { |
09b42213 | 3311 | r = build_constructor (TREE_TYPE (t), NULL); |
3312 | TREE_CONSTANT (r) = true; | |
3313 | } | |
3314 | ||
09b42213 | 3315 | return r; |
3316 | } | |
3317 | ||
3318 | /* Complain about R, a VAR_DECL, not being usable in a constant expression. | |
3319 | Shared between potential_constant_expression and | |
3320 | cxx_eval_constant_expression. */ | |
3321 | ||
3322 | static void | |
3323 | non_const_var_error (tree r) | |
3324 | { | |
3325 | tree type = TREE_TYPE (r); | |
3326 | error ("the value of %qD is not usable in a constant " | |
3327 | "expression", r); | |
3328 | /* Avoid error cascade. */ | |
3329 | if (DECL_INITIAL (r) == error_mark_node) | |
3330 | return; | |
3331 | if (DECL_DECLARED_CONSTEXPR_P (r)) | |
3332 | inform (DECL_SOURCE_LOCATION (r), | |
3333 | "%qD used in its own initializer", r); | |
3334 | else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) | |
3335 | { | |
3336 | if (!CP_TYPE_CONST_P (type)) | |
3337 | inform (DECL_SOURCE_LOCATION (r), | |
3338 | "%q#D is not const", r); | |
3339 | else if (CP_TYPE_VOLATILE_P (type)) | |
3340 | inform (DECL_SOURCE_LOCATION (r), | |
3341 | "%q#D is volatile", r); | |
3342 | else if (!DECL_INITIAL (r) | |
c8e3e744 | 3343 | || !TREE_CONSTANT (DECL_INITIAL (r)) |
3344 | || !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (r)) | |
09b42213 | 3345 | inform (DECL_SOURCE_LOCATION (r), |
3346 | "%qD was not initialized with a constant " | |
3347 | "expression", r); | |
3348 | else | |
3349 | gcc_unreachable (); | |
3350 | } | |
ac6641ca | 3351 | else if (TREE_CODE (type) == REFERENCE_TYPE) |
3352 | inform (DECL_SOURCE_LOCATION (r), | |
3353 | "%qD was not initialized with a constant " | |
3354 | "expression", r); | |
09b42213 | 3355 | else |
3356 | { | |
3357 | if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r)) | |
3358 | inform (DECL_SOURCE_LOCATION (r), | |
3359 | "%qD was not declared %<constexpr%>", r); | |
3360 | else | |
3361 | inform (DECL_SOURCE_LOCATION (r), | |
3362 | "%qD does not have integral or enumeration type", | |
3363 | r); | |
3364 | } | |
3365 | } | |
3366 | ||
3367 | /* Subroutine of cxx_eval_constant_expression. | |
3368 | Like cxx_eval_unary_expression, except for trinary expressions. */ | |
3369 | ||
3370 | static tree | |
cf72f34d | 3371 | cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3372 | bool lval, |
09b42213 | 3373 | bool *non_constant_p, bool *overflow_p) |
3374 | { | |
3375 | int i; | |
3376 | tree args[3]; | |
3377 | tree val; | |
3378 | ||
3379 | for (i = 0; i < 3; i++) | |
3380 | { | |
cf72f34d | 3381 | args[i] = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, i), |
1227ba74 | 3382 | lval, |
b2a43197 | 3383 | non_constant_p, overflow_p); |
09b42213 | 3384 | VERIFY_CONSTANT (args[i]); |
3385 | } | |
3386 | ||
3387 | val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t), | |
3388 | args[0], args[1], args[2]); | |
3389 | if (val == NULL_TREE) | |
3390 | return t; | |
3391 | VERIFY_CONSTANT (val); | |
3392 | return val; | |
3393 | } | |
3394 | ||
33603066 | 3395 | /* True if T was declared in a function declared to be constexpr, and |
3396 | therefore potentially constant in C++14. */ | |
3397 | ||
09b42213 | 3398 | bool |
3399 | var_in_constexpr_fn (tree t) | |
3400 | { | |
3401 | tree ctx = DECL_CONTEXT (t); | |
33603066 | 3402 | return (ctx && TREE_CODE (ctx) == FUNCTION_DECL |
09b42213 | 3403 | && DECL_DECLARED_CONSTEXPR_P (ctx)); |
3404 | } | |
3405 | ||
33603066 | 3406 | /* True if T was declared in a function that might be constexpr: either a |
3407 | function that was declared constexpr, or a C++17 lambda op(). */ | |
3408 | ||
3409 | bool | |
3410 | var_in_maybe_constexpr_fn (tree t) | |
3411 | { | |
40e2decb | 3412 | if (cxx_dialect >= cxx17 |
33603066 | 3413 | && DECL_FUNCTION_SCOPE_P (t) |
3414 | && LAMBDA_FUNCTION_P (DECL_CONTEXT (t))) | |
3415 | return true; | |
3416 | return var_in_constexpr_fn (t); | |
3417 | } | |
3418 | ||
93312944 | 3419 | /* We're assigning INIT to TARGET. In do_build_copy_constructor and |
3420 | build_over_call we implement trivial copy of a class with tail padding using | |
3421 | assignment of character arrays, which is valid in normal code, but not in | |
3422 | constexpr evaluation. We don't need to worry about clobbering tail padding | |
3423 | in constexpr evaluation, so strip the type punning. */ | |
3424 | ||
3425 | static void | |
3426 | maybe_simplify_trivial_copy (tree &target, tree &init) | |
3427 | { | |
3428 | if (TREE_CODE (target) == MEM_REF | |
3429 | && TREE_CODE (init) == MEM_REF | |
3430 | && TREE_TYPE (target) == TREE_TYPE (init) | |
3431 | && TREE_CODE (TREE_TYPE (target)) == ARRAY_TYPE | |
3432 | && TREE_TYPE (TREE_TYPE (target)) == unsigned_char_type_node) | |
3433 | { | |
3434 | target = build_fold_indirect_ref (TREE_OPERAND (target, 0)); | |
3435 | init = build_fold_indirect_ref (TREE_OPERAND (init, 0)); | |
3436 | } | |
3437 | } | |
3438 | ||
9c96033c | 3439 | /* Evaluate an INIT_EXPR or MODIFY_EXPR. */ |
3440 | ||
3441 | static tree | |
3442 | cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3443 | bool lval, |
9c96033c | 3444 | bool *non_constant_p, bool *overflow_p) |
3445 | { | |
3446 | constexpr_ctx new_ctx = *ctx; | |
3447 | ||
8a36d0ec | 3448 | tree init = TREE_OPERAND (t, 1); |
3449 | if (TREE_CLOBBER_P (init)) | |
3450 | /* Just ignore clobbers. */ | |
3451 | return void_node; | |
3452 | ||
9c96033c | 3453 | /* First we figure out where we're storing to. */ |
3454 | tree target = TREE_OPERAND (t, 0); | |
93312944 | 3455 | |
3456 | maybe_simplify_trivial_copy (target, init); | |
3457 | ||
9db9fc38 | 3458 | tree type = TREE_TYPE (target); |
9c96033c | 3459 | target = cxx_eval_constant_expression (ctx, target, |
f83e6885 | 3460 | true, |
b2a43197 | 3461 | non_constant_p, overflow_p); |
9c96033c | 3462 | if (*non_constant_p) |
3463 | return t; | |
3464 | ||
cf3cefc9 | 3465 | /* cxx_eval_array_reference for lval = true allows references one past |
3466 | end of array, because it does not know if it is just taking address | |
3467 | (which is valid), or actual dereference. Here we know it is | |
3468 | a dereference, so diagnose it here. */ | |
3469 | for (tree probe = target; probe; ) | |
3470 | { | |
3471 | switch (TREE_CODE (probe)) | |
3472 | { | |
3473 | case ARRAY_REF: | |
3474 | tree nelts, ary; | |
3475 | ary = TREE_OPERAND (probe, 0); | |
3476 | if (TREE_CODE (TREE_TYPE (ary)) == ARRAY_TYPE) | |
d7d265db | 3477 | { |
3478 | if (TYPE_DOMAIN (TREE_TYPE (ary))) | |
3479 | nelts = array_type_nelts_top (TREE_TYPE (ary)); | |
3480 | else | |
3481 | nelts = size_zero_node; | |
3482 | } | |
cf3cefc9 | 3483 | else if (VECTOR_TYPE_P (TREE_TYPE (ary))) |
3484 | nelts = size_int (TYPE_VECTOR_SUBPARTS (TREE_TYPE (ary))); | |
3485 | else | |
3486 | gcc_unreachable (); | |
3487 | nelts = cxx_eval_constant_expression (ctx, nelts, false, | |
3488 | non_constant_p, overflow_p); | |
3489 | VERIFY_CONSTANT (nelts); | |
3490 | gcc_assert (TREE_CODE (nelts) == INTEGER_CST | |
3491 | && TREE_CODE (TREE_OPERAND (probe, 1)) == INTEGER_CST); | |
cb7bca5f | 3492 | if (wi::to_widest (TREE_OPERAND (probe, 1)) == wi::to_widest (nelts)) |
cf3cefc9 | 3493 | { |
3494 | diag_array_subscript (ctx, ary, TREE_OPERAND (probe, 1)); | |
3495 | *non_constant_p = true; | |
3496 | return t; | |
3497 | } | |
3498 | /* FALLTHRU */ | |
3499 | ||
3500 | case BIT_FIELD_REF: | |
3501 | case COMPONENT_REF: | |
3502 | probe = TREE_OPERAND (probe, 0); | |
3503 | continue; | |
3504 | ||
3505 | default: | |
3506 | probe = NULL_TREE; | |
3507 | continue; | |
3508 | } | |
3509 | } | |
3510 | ||
9db9fc38 | 3511 | if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (target), type)) |
3512 | { | |
3513 | /* For initialization of an empty base, the original target will be | |
3514 | *(base*)this, which the above evaluation resolves to the object | |
3515 | argument, which has the derived type rather than the base type. In | |
3516 | this situation, just evaluate the initializer and return, since | |
3517 | there's no actual data to store. */ | |
3518 | gcc_assert (is_empty_class (type)); | |
3519 | return cxx_eval_constant_expression (ctx, init, false, | |
3520 | non_constant_p, overflow_p); | |
3521 | } | |
3522 | ||
9c96033c | 3523 | /* And then find the underlying variable. */ |
3524 | vec<tree,va_gc> *refs = make_tree_vector(); | |
3525 | tree object = NULL_TREE; | |
3526 | for (tree probe = target; object == NULL_TREE; ) | |
3527 | { | |
3528 | switch (TREE_CODE (probe)) | |
3529 | { | |
3530 | case BIT_FIELD_REF: | |
3531 | case COMPONENT_REF: | |
3532 | case ARRAY_REF: | |
3533 | vec_safe_push (refs, TREE_OPERAND (probe, 1)); | |
3534 | vec_safe_push (refs, TREE_TYPE (probe)); | |
3535 | probe = TREE_OPERAND (probe, 0); | |
3536 | break; | |
3537 | ||
3538 | default: | |
3539 | object = probe; | |
9c96033c | 3540 | } |
3541 | } | |
3542 | ||
3543 | /* And then find/build up our initializer for the path to the subobject | |
3544 | we're initializing. */ | |
6fe83e54 | 3545 | tree *valp; |
43b7271d | 3546 | if (object == ctx->object && VAR_P (object) |
3547 | && DECL_NAME (object) && ctx->call == NULL) | |
3548 | /* The variable we're building up an aggregate initializer for is outside | |
3549 | the constant-expression, so don't evaluate the store. We check | |
3550 | DECL_NAME to handle TARGET_EXPR temporaries, which are fair game. */ | |
3551 | valp = NULL; | |
3552 | else if (DECL_P (object)) | |
6fe83e54 | 3553 | valp = ctx->values->get (object); |
3554 | else | |
3555 | valp = NULL; | |
9c96033c | 3556 | if (!valp) |
3557 | { | |
3558 | /* A constant-expression cannot modify objects from outside the | |
3559 | constant-expression. */ | |
f83e6885 | 3560 | if (!ctx->quiet) |
ea034e2c | 3561 | error ("modification of %qE is not a constant expression", object); |
9c96033c | 3562 | *non_constant_p = true; |
3563 | return t; | |
3564 | } | |
9db9fc38 | 3565 | type = TREE_TYPE (object); |
a02b42fe | 3566 | bool no_zero_init = true; |
58b0f9ce | 3567 | |
3568 | vec<tree,va_gc> *ctors = make_tree_vector (); | |
9c96033c | 3569 | while (!refs->is_empty()) |
3570 | { | |
3571 | if (*valp == NULL_TREE) | |
3572 | { | |
3573 | *valp = build_constructor (type, NULL); | |
a02b42fe | 3574 | CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp) = no_zero_init; |
9c96033c | 3575 | } |
92fe8840 | 3576 | else if (TREE_CODE (*valp) == STRING_CST) |
3577 | { | |
3578 | /* An array was initialized with a string constant, and now | |
3579 | we're writing into one of its elements. Explode the | |
3580 | single initialization into a set of element | |
3581 | initializations. */ | |
3582 | gcc_assert (TREE_CODE (type) == ARRAY_TYPE); | |
3583 | ||
3584 | tree string = *valp; | |
3585 | tree elt_type = TREE_TYPE (type); | |
3586 | unsigned chars_per_elt = (TYPE_PRECISION (elt_type) | |
3587 | / TYPE_PRECISION (char_type_node)); | |
3588 | unsigned num_elts = TREE_STRING_LENGTH (string) / chars_per_elt; | |
3589 | tree ary_ctor = build_constructor (type, NULL); | |
3590 | ||
3591 | vec_safe_reserve (CONSTRUCTOR_ELTS (ary_ctor), num_elts); | |
3592 | for (unsigned ix = 0; ix != num_elts; ix++) | |
3593 | { | |
3594 | constructor_elt elt = | |
3595 | { | |
3596 | build_int_cst (size_type_node, ix), | |
3597 | extract_string_elt (string, chars_per_elt, ix) | |
3598 | }; | |
3599 | CONSTRUCTOR_ELTS (ary_ctor)->quick_push (elt); | |
3600 | } | |
3601 | ||
3602 | *valp = ary_ctor; | |
3603 | } | |
3604 | ||
a02b42fe | 3605 | /* If the value of object is already zero-initialized, any new ctors for |
3606 | subobjects will also be zero-initialized. */ | |
3607 | no_zero_init = CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp); | |
9c96033c | 3608 | |
58b0f9ce | 3609 | vec_safe_push (ctors, *valp); |
3610 | ||
7963b19d | 3611 | enum tree_code code = TREE_CODE (type); |
9c96033c | 3612 | type = refs->pop(); |
7963b19d | 3613 | tree index = refs->pop(); |
9c96033c | 3614 | |
9c96033c | 3615 | constructor_elt *cep = NULL; |
7963b19d | 3616 | if (code == ARRAY_TYPE) |
3617 | { | |
3618 | HOST_WIDE_INT i | |
3619 | = find_array_ctor_elt (*valp, index, /*insert*/true); | |
3620 | gcc_assert (i >= 0); | |
3621 | cep = CONSTRUCTOR_ELT (*valp, i); | |
3622 | gcc_assert (TREE_CODE (cep->index) != RANGE_EXPR); | |
3623 | } | |
3624 | else | |
3625 | { | |
3626 | gcc_assert (TREE_CODE (index) == FIELD_DECL); | |
13ee2de7 | 3627 | |
3628 | /* We must keep the CONSTRUCTOR's ELTS in FIELD order. | |
3629 | Usually we meet initializers in that order, but it is | |
3630 | possible for base types to be placed not in program | |
3631 | order. */ | |
3632 | tree fields = TYPE_FIELDS (DECL_CONTEXT (index)); | |
3633 | unsigned HOST_WIDE_INT idx; | |
3634 | ||
ef782365 | 3635 | if (code == UNION_TYPE && CONSTRUCTOR_NELTS (*valp) |
3636 | && CONSTRUCTOR_ELT (*valp, 0)->index != index) | |
3637 | /* Changing active member. */ | |
3638 | vec_safe_truncate (CONSTRUCTOR_ELTS (*valp), 0); | |
3639 | ||
13ee2de7 | 3640 | for (idx = 0; |
7963b19d | 3641 | vec_safe_iterate (CONSTRUCTOR_ELTS (*valp), idx, &cep); |
13ee2de7 | 3642 | idx++, fields = DECL_CHAIN (fields)) |
7963b19d | 3643 | { |
13ee2de7 | 3644 | if (index == cep->index) |
3645 | goto found; | |
3646 | ||
3647 | /* The field we're initializing must be on the field | |
3648 | list. Look to see if it is present before the | |
3649 | field the current ELT initializes. */ | |
3650 | for (; fields != cep->index; fields = DECL_CHAIN (fields)) | |
3651 | if (index == fields) | |
3652 | goto insert; | |
7963b19d | 3653 | } |
13ee2de7 | 3654 | |
3655 | /* We fell off the end of the CONSTRUCTOR, so insert a new | |
3656 | entry at the end. */ | |
3657 | insert: | |
3658 | { | |
3659 | constructor_elt ce = { index, NULL_TREE }; | |
3660 | ||
3661 | vec_safe_insert (CONSTRUCTOR_ELTS (*valp), idx, ce); | |
3662 | cep = CONSTRUCTOR_ELT (*valp, idx); | |
3663 | } | |
3664 | found:; | |
7963b19d | 3665 | } |
9c96033c | 3666 | valp = &cep->value; |
3667 | } | |
3668 | release_tree_vector (refs); | |
3669 | ||
469dc5a6 | 3670 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) |
9c96033c | 3671 | { |
3672 | /* Create a new CONSTRUCTOR in case evaluation of the initializer | |
3673 | wants to modify it. */ | |
469dc5a6 | 3674 | if (*valp == NULL_TREE) |
6cded085 | 3675 | { |
6993e708 | 3676 | *valp = build_constructor (type, NULL); |
3677 | CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp) = no_zero_init; | |
6cded085 | 3678 | } |
6993e708 | 3679 | else if (TREE_CODE (*valp) == PTRMEM_CST) |
3680 | *valp = cplus_expand_constant (*valp); | |
3681 | new_ctx.ctor = *valp; | |
9c96033c | 3682 | new_ctx.object = target; |
3683 | } | |
3684 | ||
8a36d0ec | 3685 | init = cxx_eval_constant_expression (&new_ctx, init, false, |
3686 | non_constant_p, overflow_p); | |
7b9f713d | 3687 | /* Don't share a CONSTRUCTOR that might be changed later. */ |
e283bb4f | 3688 | init = unshare_constructor (init); |
9c96033c | 3689 | if (target == object) |
5579a199 | 3690 | /* The hash table might have moved since the get earlier. */ |
3691 | valp = ctx->values->get (object); | |
3692 | ||
3693 | if (TREE_CODE (init) == CONSTRUCTOR) | |
469dc5a6 | 3694 | { |
5579a199 | 3695 | /* An outer ctx->ctor might be pointing to *valp, so replace |
3696 | its contents. */ | |
3697 | CONSTRUCTOR_ELTS (*valp) = CONSTRUCTOR_ELTS (init); | |
3698 | TREE_CONSTANT (*valp) = TREE_CONSTANT (init); | |
3699 | TREE_SIDE_EFFECTS (*valp) = TREE_SIDE_EFFECTS (init); | |
b9786e35 | 3700 | CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp) |
3701 | = CONSTRUCTOR_NO_IMPLICIT_ZERO (init); | |
469dc5a6 | 3702 | } |
9c96033c | 3703 | else |
5579a199 | 3704 | *valp = init; |
58b0f9ce | 3705 | |
5579a199 | 3706 | /* Update TREE_CONSTANT and TREE_SIDE_EFFECTS on enclosing |
3707 | CONSTRUCTORs, if any. */ | |
3708 | tree elt; | |
3709 | unsigned i; | |
3710 | bool c = TREE_CONSTANT (init); | |
3711 | bool s = TREE_SIDE_EFFECTS (init); | |
3712 | if (!c || s) | |
3713 | FOR_EACH_VEC_SAFE_ELT (ctors, i, elt) | |
3714 | { | |
3715 | if (!c) | |
3716 | TREE_CONSTANT (elt) = false; | |
3717 | if (s) | |
3718 | TREE_SIDE_EFFECTS (elt) = true; | |
3719 | } | |
58b0f9ce | 3720 | release_tree_vector (ctors); |
9c96033c | 3721 | |
3722 | if (*non_constant_p) | |
3723 | return t; | |
1227ba74 | 3724 | else if (lval) |
9c96033c | 3725 | return target; |
3726 | else | |
dfac7dd2 | 3727 | return init; |
9c96033c | 3728 | } |
3729 | ||
3730 | /* Evaluate a ++ or -- expression. */ | |
3731 | ||
3732 | static tree | |
3733 | cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3734 | bool lval, |
9c96033c | 3735 | bool *non_constant_p, bool *overflow_p) |
3736 | { | |
3737 | enum tree_code code = TREE_CODE (t); | |
3738 | tree type = TREE_TYPE (t); | |
3739 | tree op = TREE_OPERAND (t, 0); | |
3740 | tree offset = TREE_OPERAND (t, 1); | |
3741 | gcc_assert (TREE_CONSTANT (offset)); | |
3742 | ||
3743 | /* The operand as an lvalue. */ | |
f83e6885 | 3744 | op = cxx_eval_constant_expression (ctx, op, true, |
b2a43197 | 3745 | non_constant_p, overflow_p); |
9c96033c | 3746 | |
3747 | /* The operand as an rvalue. */ | |
c017458d | 3748 | tree val |
3749 | = cxx_eval_constant_expression (ctx, op, false, | |
3750 | non_constant_p, overflow_p); | |
35f2c28f | 3751 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
3752 | a local array in a constexpr function. */ | |
3753 | bool ptr = POINTER_TYPE_P (TREE_TYPE (val)); | |
3754 | if (!ptr) | |
3755 | VERIFY_CONSTANT (val); | |
9c96033c | 3756 | |
3757 | /* The modified value. */ | |
3758 | bool inc = (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR); | |
c8a8f7ad | 3759 | tree mod; |
3760 | if (POINTER_TYPE_P (type)) | |
3761 | { | |
3762 | /* The middle end requires pointers to use POINTER_PLUS_EXPR. */ | |
3763 | offset = convert_to_ptrofftype (offset); | |
3764 | if (!inc) | |
3765 | offset = fold_build1 (NEGATE_EXPR, TREE_TYPE (offset), offset); | |
3766 | mod = fold_build2 (POINTER_PLUS_EXPR, type, val, offset); | |
3767 | } | |
3768 | else | |
3769 | mod = fold_build2 (inc ? PLUS_EXPR : MINUS_EXPR, type, val, offset); | |
35f2c28f | 3770 | if (!ptr) |
3771 | VERIFY_CONSTANT (mod); | |
9c96033c | 3772 | |
3773 | /* Storing the modified value. */ | |
3774 | tree store = build2 (MODIFY_EXPR, type, op, mod); | |
f83e6885 | 3775 | cxx_eval_constant_expression (ctx, store, |
b2a43197 | 3776 | true, non_constant_p, overflow_p); |
9c96033c | 3777 | |
3778 | /* And the value of the expression. */ | |
3779 | if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) | |
3780 | { | |
3781 | /* Prefix ops are lvalues. */ | |
1227ba74 | 3782 | if (lval) |
9c96033c | 3783 | return op; |
3784 | else | |
3785 | /* But we optimize when the caller wants an rvalue. */ | |
3786 | return mod; | |
3787 | } | |
3788 | else | |
3789 | /* Postfix ops are rvalues. */ | |
3790 | return val; | |
3791 | } | |
3792 | ||
00f21715 | 3793 | /* Predicates for the meaning of *jump_target. */ |
3794 | ||
3795 | static bool | |
3796 | returns (tree *jump_target) | |
3797 | { | |
3798 | return *jump_target | |
d29e4e8c | 3799 | && (TREE_CODE (*jump_target) == RETURN_EXPR |
3800 | || (TREE_CODE (*jump_target) == LABEL_DECL | |
3801 | && LABEL_DECL_CDTOR (*jump_target))); | |
00f21715 | 3802 | } |
3803 | ||
3804 | static bool | |
3805 | breaks (tree *jump_target) | |
3806 | { | |
3807 | return *jump_target | |
cf03ba19 | 3808 | && ((TREE_CODE (*jump_target) == LABEL_DECL |
3809 | && LABEL_DECL_BREAK (*jump_target)) | |
3810 | || TREE_CODE (*jump_target) == EXIT_EXPR); | |
00f21715 | 3811 | } |
3812 | ||
3813 | static bool | |
3814 | continues (tree *jump_target) | |
3815 | { | |
3816 | return *jump_target | |
3817 | && TREE_CODE (*jump_target) == LABEL_DECL | |
3818 | && LABEL_DECL_CONTINUE (*jump_target); | |
3819 | } | |
3820 | ||
3821 | static bool | |
3822 | switches (tree *jump_target) | |
3823 | { | |
3824 | return *jump_target | |
3825 | && TREE_CODE (*jump_target) == INTEGER_CST; | |
3826 | } | |
3827 | ||
3828 | /* Subroutine of cxx_eval_statement_list. Determine whether the statement | |
2a2770c6 | 3829 | STMT matches *jump_target. If we're looking for a case label and we see |
3830 | the default label, note it in ctx->css_state. */ | |
00f21715 | 3831 | |
3832 | static bool | |
2a2770c6 | 3833 | label_matches (const constexpr_ctx *ctx, tree *jump_target, tree stmt) |
00f21715 | 3834 | { |
00f21715 | 3835 | switch (TREE_CODE (*jump_target)) |
3836 | { | |
3837 | case LABEL_DECL: | |
3838 | if (TREE_CODE (stmt) == LABEL_EXPR | |
3839 | && LABEL_EXPR_LABEL (stmt) == *jump_target) | |
3840 | return true; | |
3841 | break; | |
3842 | ||
3843 | case INTEGER_CST: | |
3844 | if (TREE_CODE (stmt) == CASE_LABEL_EXPR) | |
3845 | { | |
2a2770c6 | 3846 | gcc_assert (ctx->css_state != NULL); |
00f21715 | 3847 | if (!CASE_LOW (stmt)) |
2a2770c6 | 3848 | { |
3849 | /* default: should appear just once in a SWITCH_EXPR | |
3850 | body (excluding nested SWITCH_EXPR). */ | |
3851 | gcc_assert (*ctx->css_state != css_default_seen); | |
3852 | /* When evaluating SWITCH_EXPR body for the second time, | |
3853 | return true for the default: label. */ | |
3854 | if (*ctx->css_state == css_default_processing) | |
3855 | return true; | |
3856 | *ctx->css_state = css_default_seen; | |
3857 | } | |
83c375ba | 3858 | else if (CASE_HIGH (stmt)) |
3859 | { | |
3860 | if (tree_int_cst_le (CASE_LOW (stmt), *jump_target) | |
3861 | && tree_int_cst_le (*jump_target, CASE_HIGH (stmt))) | |
3862 | return true; | |
3863 | } | |
00f21715 | 3864 | else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt))) |
3865 | return true; | |
3866 | } | |
3867 | break; | |
3868 | ||
3869 | default: | |
3870 | gcc_unreachable (); | |
3871 | } | |
3872 | return false; | |
3873 | } | |
3874 | ||
3875 | /* Evaluate a STATEMENT_LIST for side-effects. Handles various jump | |
3876 | semantics, for switch, break, continue, and return. */ | |
3877 | ||
3878 | static tree | |
3879 | cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3880 | bool *non_constant_p, bool *overflow_p, |
3881 | tree *jump_target) | |
3882 | { | |
3883 | tree_stmt_iterator i; | |
da7981e0 | 3884 | tree local_target; |
efea7c64 | 3885 | /* In a statement-expression we want to return the last value. |
3886 | For empty statement expression return void_node. */ | |
3887 | tree r = void_node; | |
da7981e0 | 3888 | if (!jump_target) |
3889 | { | |
3890 | local_target = NULL_TREE; | |
3891 | jump_target = &local_target; | |
3892 | } | |
00f21715 | 3893 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) |
3894 | { | |
00f21715 | 3895 | tree stmt = tsi_stmt (i); |
442c4003 | 3896 | if (TREE_CODE (stmt) == DEBUG_BEGIN_STMT) |
3897 | continue; | |
da7981e0 | 3898 | r = cxx_eval_constant_expression (ctx, stmt, false, |
3899 | non_constant_p, overflow_p, | |
3900 | jump_target); | |
00f21715 | 3901 | if (*non_constant_p) |
3902 | break; | |
3903 | if (returns (jump_target) || breaks (jump_target)) | |
3904 | break; | |
3905 | } | |
da7981e0 | 3906 | return r; |
00f21715 | 3907 | } |
3908 | ||
3909 | /* Evaluate a LOOP_EXPR for side-effects. Handles break and return | |
3910 | semantics; continue semantics are covered by cxx_eval_statement_list. */ | |
3911 | ||
3912 | static tree | |
3913 | cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3914 | bool *non_constant_p, bool *overflow_p, |
3915 | tree *jump_target) | |
3916 | { | |
2631cb67 | 3917 | constexpr_ctx new_ctx = *ctx; |
3918 | ||
00f21715 | 3919 | tree body = TREE_OPERAND (t, 0); |
21483ab7 | 3920 | int count = 0; |
5370eb8d | 3921 | do |
00f21715 | 3922 | { |
2631cb67 | 3923 | hash_set<tree> save_exprs; |
3924 | new_ctx.save_exprs = &save_exprs; | |
3925 | ||
cf03ba19 | 3926 | cxx_eval_constant_expression (&new_ctx, body, /*lval*/false, |
3927 | non_constant_p, overflow_p, jump_target); | |
2631cb67 | 3928 | |
3929 | /* Forget saved values of SAVE_EXPRs. */ | |
3930 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
3931 | iter != save_exprs.end(); ++iter) | |
3932 | new_ctx.values->remove (*iter); | |
21483ab7 | 3933 | if (++count >= constexpr_loop_limit) |
3934 | { | |
3935 | if (!ctx->quiet) | |
3936 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
5967b28b | 3937 | "%<constexpr%> loop iteration count exceeds limit of %d " |
21483ab7 | 3938 | "(use -fconstexpr-loop-limit= to increase the limit)", |
3939 | constexpr_loop_limit); | |
3940 | *non_constant_p = true; | |
3941 | break; | |
3942 | } | |
00f21715 | 3943 | } |
2a2770c6 | 3944 | while (!returns (jump_target) |
3945 | && !breaks (jump_target) | |
3946 | && !switches (jump_target) | |
3947 | && !*non_constant_p); | |
5370eb8d | 3948 | |
00f21715 | 3949 | if (breaks (jump_target)) |
3950 | *jump_target = NULL_TREE; | |
2631cb67 | 3951 | |
00f21715 | 3952 | return NULL_TREE; |
3953 | } | |
3954 | ||
3955 | /* Evaluate a SWITCH_EXPR for side-effects. Handles switch and break jump | |
3956 | semantics. */ | |
3957 | ||
3958 | static tree | |
3959 | cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3960 | bool *non_constant_p, bool *overflow_p, |
3961 | tree *jump_target) | |
3962 | { | |
3963 | tree cond = TREE_OPERAND (t, 0); | |
f83e6885 | 3964 | cond = cxx_eval_constant_expression (ctx, cond, false, |
b2a43197 | 3965 | non_constant_p, overflow_p); |
00f21715 | 3966 | VERIFY_CONSTANT (cond); |
3967 | *jump_target = cond; | |
3968 | ||
3969 | tree body = TREE_OPERAND (t, 1); | |
2a2770c6 | 3970 | constexpr_ctx new_ctx = *ctx; |
3971 | constexpr_switch_state css = css_default_not_seen; | |
3972 | new_ctx.css_state = &css; | |
3973 | cxx_eval_constant_expression (&new_ctx, body, false, | |
3974 | non_constant_p, overflow_p, jump_target); | |
3975 | if (switches (jump_target) && css == css_default_seen) | |
3976 | { | |
3977 | /* If the SWITCH_EXPR body has default: label, process it once again, | |
3978 | this time instructing label_matches to return true for default: | |
3979 | label on switches (jump_target). */ | |
3980 | css = css_default_processing; | |
3981 | cxx_eval_constant_expression (&new_ctx, body, false, | |
3982 | non_constant_p, overflow_p, jump_target); | |
3983 | } | |
00f21715 | 3984 | if (breaks (jump_target) || switches (jump_target)) |
3985 | *jump_target = NULL_TREE; | |
3986 | return NULL_TREE; | |
3987 | } | |
3988 | ||
85de9604 | 3989 | /* Find the object of TYPE under initialization in CTX. */ |
3990 | ||
3991 | static tree | |
3992 | lookup_placeholder (const constexpr_ctx *ctx, bool lval, tree type) | |
3993 | { | |
def8e41f | 3994 | if (!ctx) |
85de9604 | 3995 | return NULL_TREE; |
3996 | ||
3997 | /* We could use ctx->object unconditionally, but using ctx->ctor when we | |
3998 | can is a minor optimization. */ | |
def8e41f | 3999 | if (!lval && ctx->ctor && same_type_p (TREE_TYPE (ctx->ctor), type)) |
85de9604 | 4000 | return ctx->ctor; |
4001 | ||
def8e41f | 4002 | if (!ctx->object) |
4003 | return NULL_TREE; | |
4004 | ||
85de9604 | 4005 | /* Since an object cannot have a field of its own type, we can search outward |
4006 | from ctx->object to find the unique containing object of TYPE. */ | |
4007 | tree ob = ctx->object; | |
4008 | while (ob) | |
4009 | { | |
4010 | if (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (ob), type)) | |
4011 | break; | |
4012 | if (handled_component_p (ob)) | |
4013 | ob = TREE_OPERAND (ob, 0); | |
4014 | else | |
4015 | ob = NULL_TREE; | |
4016 | } | |
4017 | ||
4018 | return ob; | |
4019 | } | |
4020 | ||
09b42213 | 4021 | /* Attempt to reduce the expression T to a constant value. |
4022 | On failure, issue diagnostic and return error_mark_node. */ | |
4023 | /* FIXME unify with c_fully_fold */ | |
9c96033c | 4024 | /* FIXME overflow_p is too global */ |
09b42213 | 4025 | |
4026 | static tree | |
cf72f34d | 4027 | cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 4028 | bool lval, |
00f21715 | 4029 | bool *non_constant_p, bool *overflow_p, |
4030 | tree *jump_target) | |
09b42213 | 4031 | { |
cf72f34d | 4032 | constexpr_ctx new_ctx; |
09b42213 | 4033 | tree r = t; |
4034 | ||
2a2770c6 | 4035 | if (jump_target && *jump_target) |
4036 | { | |
4037 | /* If we are jumping, ignore all statements/expressions except those | |
4038 | that could have LABEL_EXPR or CASE_LABEL_EXPR in their bodies. */ | |
4039 | switch (TREE_CODE (t)) | |
4040 | { | |
4041 | case BIND_EXPR: | |
4042 | case STATEMENT_LIST: | |
4043 | case LOOP_EXPR: | |
4044 | case COND_EXPR: | |
4045 | break; | |
4046 | case LABEL_EXPR: | |
4047 | case CASE_LABEL_EXPR: | |
4048 | if (label_matches (ctx, jump_target, t)) | |
4049 | /* Found it. */ | |
4050 | *jump_target = NULL_TREE; | |
4051 | return NULL_TREE; | |
4052 | default: | |
4053 | return NULL_TREE; | |
4054 | } | |
4055 | } | |
09b42213 | 4056 | if (t == error_mark_node) |
4057 | { | |
4058 | *non_constant_p = true; | |
4059 | return t; | |
4060 | } | |
4061 | if (CONSTANT_CLASS_P (t)) | |
4062 | { | |
c4fa85c9 | 4063 | if (TREE_OVERFLOW (t)) |
4064 | { | |
4065 | if (!ctx->quiet) | |
4066 | permerror (input_location, "overflow in constant expression"); | |
4067 | if (!flag_permissive || ctx->quiet) | |
4068 | *overflow_p = true; | |
4069 | } | |
cb768824 | 4070 | |
4071 | if (TREE_CODE (t) == INTEGER_CST | |
4072 | && TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE | |
4073 | && !integer_zerop (t)) | |
4074 | { | |
4075 | if (!ctx->quiet) | |
4076 | error ("value %qE of type %qT is not a constant expression", | |
4077 | t, TREE_TYPE (t)); | |
4078 | *non_constant_p = true; | |
4079 | } | |
4080 | ||
09b42213 | 4081 | return t; |
4082 | } | |
09b42213 | 4083 | |
cb768824 | 4084 | tree_code tcode = TREE_CODE (t); |
4085 | switch (tcode) | |
09b42213 | 4086 | { |
9c96033c | 4087 | case RESULT_DECL: |
1227ba74 | 4088 | if (lval) |
9c96033c | 4089 | return t; |
4090 | /* We ask for an rvalue for the RESULT_DECL when indirecting | |
92a9c89e | 4091 | through an invisible reference, or in named return value |
4092 | optimization. */ | |
9c96033c | 4093 | return (*ctx->values->get (t)); |
4094 | ||
09b42213 | 4095 | case VAR_DECL: |
9c8aeb66 | 4096 | if (DECL_HAS_VALUE_EXPR_P (t)) |
33603066 | 4097 | return cxx_eval_constant_expression (ctx, DECL_VALUE_EXPR (t), |
4098 | lval, non_constant_p, overflow_p); | |
e3533433 | 4099 | /* fall through */ |
8b2b2f24 | 4100 | case CONST_DECL: |
4101 | /* We used to not check lval for CONST_DECL, but darwin.c uses | |
4102 | CONST_DECL for aggregate constants. */ | |
1227ba74 | 4103 | if (lval) |
09b42213 | 4104 | return t; |
594cc00c | 4105 | if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
4106 | && is_really_empty_class (TREE_TYPE (t))) | |
c7282bf2 | 4107 | { |
4108 | /* If the class is empty, we aren't actually loading anything. */ | |
4109 | r = build_constructor (TREE_TYPE (t), NULL); | |
4110 | TREE_CONSTANT (r) = true; | |
4111 | } | |
4112 | else if (ctx->strict) | |
2055d27a | 4113 | r = decl_really_constant_value (t); |
4114 | else | |
4115 | r = decl_constant_value (t); | |
09b42213 | 4116 | if (TREE_CODE (r) == TARGET_EXPR |
4117 | && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR) | |
4118 | r = TARGET_EXPR_INITIAL (r); | |
f4ae4202 | 4119 | if (VAR_P (r)) |
cf72f34d | 4120 | if (tree *p = ctx->values->get (r)) |
a143e277 | 4121 | if (*p != NULL_TREE) |
4122 | r = *p; | |
09b42213 | 4123 | if (DECL_P (r)) |
4124 | { | |
f83e6885 | 4125 | if (!ctx->quiet) |
09b42213 | 4126 | non_const_var_error (r); |
4127 | *non_constant_p = true; | |
4128 | } | |
4129 | break; | |
4130 | ||
90567983 | 4131 | case DEBUG_BEGIN_STMT: |
4132 | /* ??? It might be nice to retain this information somehow, so | |
4133 | as to be able to step into a constexpr function call. */ | |
4134 | /* Fall through. */ | |
4135 | ||
09b42213 | 4136 | case FUNCTION_DECL: |
4137 | case TEMPLATE_DECL: | |
4138 | case LABEL_DECL: | |
00f21715 | 4139 | case LABEL_EXPR: |
4140 | case CASE_LABEL_EXPR: | |
2a2770c6 | 4141 | case PREDICT_EXPR: |
09b42213 | 4142 | return t; |
4143 | ||
4144 | case PARM_DECL: | |
88a59139 | 4145 | if (lval && TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE) |
9c96033c | 4146 | /* glvalue use. */; |
4147 | else if (tree *p = ctx->values->get (r)) | |
4148 | r = *p; | |
1227ba74 | 4149 | else if (lval) |
09b42213 | 4150 | /* Defer in case this is only used for its type. */; |
1eb418cc | 4151 | else if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE) |
4152 | /* Defer, there's no lvalue->rvalue conversion. */; | |
53d2f3de | 4153 | else if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
4154 | && is_really_empty_class (TREE_TYPE (t))) | |
a6613de7 | 4155 | { |
4156 | /* If the class is empty, we aren't actually loading anything. */ | |
4157 | r = build_constructor (TREE_TYPE (t), NULL); | |
4158 | TREE_CONSTANT (r) = true; | |
4159 | } | |
09b42213 | 4160 | else |
4161 | { | |
f83e6885 | 4162 | if (!ctx->quiet) |
09b42213 | 4163 | error ("%qE is not a constant expression", t); |
4164 | *non_constant_p = true; | |
4165 | } | |
4166 | break; | |
4167 | ||
4168 | case CALL_EXPR: | |
4169 | case AGGR_INIT_EXPR: | |
1227ba74 | 4170 | r = cxx_eval_call_expression (ctx, t, lval, |
09b42213 | 4171 | non_constant_p, overflow_p); |
4172 | break; | |
4173 | ||
9c96033c | 4174 | case DECL_EXPR: |
4175 | { | |
4176 | r = DECL_EXPR_DECL (t); | |
4177 | if (AGGREGATE_TYPE_P (TREE_TYPE (r)) | |
4178 | || VECTOR_TYPE_P (TREE_TYPE (r))) | |
4179 | { | |
4180 | new_ctx = *ctx; | |
4181 | new_ctx.object = r; | |
4182 | new_ctx.ctor = build_constructor (TREE_TYPE (r), NULL); | |
4183 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
4184 | new_ctx.values->put (r, new_ctx.ctor); | |
4185 | ctx = &new_ctx; | |
4186 | } | |
4187 | ||
4188 | if (tree init = DECL_INITIAL (r)) | |
4189 | { | |
4190 | init = cxx_eval_constant_expression (ctx, init, | |
f83e6885 | 4191 | false, |
b2a43197 | 4192 | non_constant_p, overflow_p); |
5898f0d7 | 4193 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 4194 | init = unshare_constructor (init); |
9c96033c | 4195 | ctx->values->put (r, init); |
4196 | } | |
4197 | else if (ctx == &new_ctx) | |
4198 | /* We gave it a CONSTRUCTOR above. */; | |
4199 | else | |
4200 | ctx->values->put (r, NULL_TREE); | |
4201 | } | |
4202 | break; | |
4203 | ||
09b42213 | 4204 | case TARGET_EXPR: |
4205 | if (!literal_type_p (TREE_TYPE (t))) | |
4206 | { | |
f83e6885 | 4207 | if (!ctx->quiet) |
09b42213 | 4208 | { |
4209 | error ("temporary of non-literal type %qT in a " | |
4210 | "constant expression", TREE_TYPE (t)); | |
4211 | explain_non_literal_class (TREE_TYPE (t)); | |
4212 | } | |
4213 | *non_constant_p = true; | |
4214 | break; | |
4215 | } | |
cf72f34d | 4216 | if ((AGGREGATE_TYPE_P (TREE_TYPE (t)) || VECTOR_TYPE_P (TREE_TYPE (t)))) |
4217 | { | |
4218 | /* We're being expanded without an explicit target, so start | |
4219 | initializing a new object; expansion with an explicit target | |
4220 | strips the TARGET_EXPR before we get here. */ | |
4221 | new_ctx = *ctx; | |
4222 | new_ctx.ctor = build_constructor (TREE_TYPE (t), NULL); | |
4223 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
4224 | new_ctx.object = TARGET_EXPR_SLOT (t); | |
4225 | ctx->values->put (new_ctx.object, new_ctx.ctor); | |
4226 | ctx = &new_ctx; | |
4227 | } | |
1227ba74 | 4228 | /* Pass false for 'lval' because this indicates |
09b42213 | 4229 | initialization of a temporary. */ |
cf72f34d | 4230 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 4231 | false, |
b2a43197 | 4232 | non_constant_p, overflow_p); |
09b42213 | 4233 | if (!*non_constant_p) |
4234 | /* Adjust the type of the result to the type of the temporary. */ | |
4235 | r = adjust_temp_type (TREE_TYPE (t), r); | |
1227ba74 | 4236 | if (lval) |
1eb418cc | 4237 | { |
4238 | tree slot = TARGET_EXPR_SLOT (t); | |
e283bb4f | 4239 | r = unshare_constructor (r); |
1eb418cc | 4240 | ctx->values->put (slot, r); |
4241 | return slot; | |
4242 | } | |
09b42213 | 4243 | break; |
4244 | ||
9c96033c | 4245 | case INIT_EXPR: |
9c96033c | 4246 | case MODIFY_EXPR: |
2a2770c6 | 4247 | gcc_assert (jump_target == NULL || *jump_target == NULL_TREE); |
1227ba74 | 4248 | r = cxx_eval_store_expression (ctx, t, lval, |
9c96033c | 4249 | non_constant_p, overflow_p); |
4250 | break; | |
4251 | ||
09b42213 | 4252 | case SCOPE_REF: |
cf72f34d | 4253 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 4254 | lval, |
b2a43197 | 4255 | non_constant_p, overflow_p); |
09b42213 | 4256 | break; |
4257 | ||
4258 | case RETURN_EXPR: | |
10fb495c | 4259 | if (TREE_OPERAND (t, 0) != NULL_TREE) |
4260 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
4261 | lval, | |
4262 | non_constant_p, overflow_p); | |
2c572f5f | 4263 | if (jump_target) |
4264 | *jump_target = t; | |
4265 | else | |
4266 | { | |
4267 | /* Can happen with ({ return true; }) && false; passed to | |
4268 | maybe_constant_value. There is nothing to jump over in this | |
4269 | case, and the bug will be diagnosed later. */ | |
4270 | gcc_assert (ctx->quiet); | |
4271 | *non_constant_p = true; | |
4272 | } | |
00f21715 | 4273 | break; |
4274 | ||
e0e672a0 | 4275 | case SAVE_EXPR: |
4276 | /* Avoid evaluating a SAVE_EXPR more than once. */ | |
4277 | if (tree *p = ctx->values->get (t)) | |
4278 | r = *p; | |
4279 | else | |
4280 | { | |
c8f6aeb1 | 4281 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), false, |
e0e672a0 | 4282 | non_constant_p, overflow_p); |
4283 | ctx->values->put (t, r); | |
2631cb67 | 4284 | if (ctx->save_exprs) |
4285 | ctx->save_exprs->add (t); | |
e0e672a0 | 4286 | } |
4287 | break; | |
4288 | ||
09b42213 | 4289 | case NON_LVALUE_EXPR: |
4290 | case TRY_CATCH_EXPR: | |
7f67d68c | 4291 | case TRY_BLOCK: |
09b42213 | 4292 | case CLEANUP_POINT_EXPR: |
4293 | case MUST_NOT_THROW_EXPR: | |
9c96033c | 4294 | case EXPR_STMT: |
4295 | case EH_SPEC_BLOCK: | |
cf72f34d | 4296 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 4297 | lval, |
00f21715 | 4298 | non_constant_p, overflow_p, |
4299 | jump_target); | |
09b42213 | 4300 | break; |
4301 | ||
7f67d68c | 4302 | case TRY_FINALLY_EXPR: |
4303 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4304 | non_constant_p, overflow_p, | |
4305 | jump_target); | |
4306 | if (!*non_constant_p) | |
4307 | /* Also evaluate the cleanup. */ | |
4308 | cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), true, | |
4309 | non_constant_p, overflow_p, | |
4310 | jump_target); | |
4311 | break; | |
4312 | ||
09b42213 | 4313 | /* These differ from cxx_eval_unary_expression in that this doesn't |
4314 | check for a constant operand or result; an address can be | |
4315 | constant without its operand being, and vice versa. */ | |
d2c63826 | 4316 | case MEM_REF: |
09b42213 | 4317 | case INDIRECT_REF: |
1227ba74 | 4318 | r = cxx_eval_indirect_ref (ctx, t, lval, |
09b42213 | 4319 | non_constant_p, overflow_p); |
4320 | break; | |
4321 | ||
4322 | case ADDR_EXPR: | |
4323 | { | |
4324 | tree oldop = TREE_OPERAND (t, 0); | |
cf72f34d | 4325 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4326 | /*lval*/true, |
b2a43197 | 4327 | non_constant_p, overflow_p); |
09b42213 | 4328 | /* Don't VERIFY_CONSTANT here. */ |
4329 | if (*non_constant_p) | |
4330 | return t; | |
1eb418cc | 4331 | gcc_checking_assert (TREE_CODE (op) != CONSTRUCTOR); |
09b42213 | 4332 | /* This function does more aggressive folding than fold itself. */ |
4333 | r = build_fold_addr_expr_with_type (op, TREE_TYPE (t)); | |
4334 | if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop) | |
4335 | return t; | |
4336 | break; | |
4337 | } | |
4338 | ||
4339 | case REALPART_EXPR: | |
4340 | case IMAGPART_EXPR: | |
6fe424c2 | 4341 | if (lval) |
4342 | { | |
4343 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4344 | non_constant_p, overflow_p); | |
4345 | if (r == error_mark_node) | |
4346 | ; | |
4347 | else if (r == TREE_OPERAND (t, 0)) | |
4348 | r = t; | |
4349 | else | |
4350 | r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), r); | |
4351 | break; | |
4352 | } | |
4353 | /* FALLTHRU */ | |
09b42213 | 4354 | case CONJ_EXPR: |
4355 | case FIX_TRUNC_EXPR: | |
4356 | case FLOAT_EXPR: | |
4357 | case NEGATE_EXPR: | |
4358 | case ABS_EXPR: | |
4359 | case BIT_NOT_EXPR: | |
4360 | case TRUTH_NOT_EXPR: | |
4361 | case FIXED_CONVERT_EXPR: | |
1227ba74 | 4362 | r = cxx_eval_unary_expression (ctx, t, lval, |
09b42213 | 4363 | non_constant_p, overflow_p); |
4364 | break; | |
4365 | ||
4366 | case SIZEOF_EXPR: | |
d2c63826 | 4367 | r = fold_sizeof_expr (t); |
09b42213 | 4368 | VERIFY_CONSTANT (r); |
4369 | break; | |
4370 | ||
4371 | case COMPOUND_EXPR: | |
4372 | { | |
4373 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
4374 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
4375 | introduced by build_call_a. */ | |
4376 | tree op0 = TREE_OPERAND (t, 0); | |
4377 | tree op1 = TREE_OPERAND (t, 1); | |
4378 | STRIP_NOPS (op1); | |
4379 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
4380 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
f83e6885 | 4381 | r = cxx_eval_constant_expression (ctx, op0, |
1227ba74 | 4382 | lval, non_constant_p, overflow_p, |
00f21715 | 4383 | jump_target); |
09b42213 | 4384 | else |
4385 | { | |
4386 | /* Check that the LHS is constant and then discard it. */ | |
f83e6885 | 4387 | cxx_eval_constant_expression (ctx, op0, |
c8f6aeb1 | 4388 | true, non_constant_p, overflow_p, |
00f21715 | 4389 | jump_target); |
cf03ba19 | 4390 | if (*non_constant_p) |
4391 | return t; | |
09b42213 | 4392 | op1 = TREE_OPERAND (t, 1); |
f83e6885 | 4393 | r = cxx_eval_constant_expression (ctx, op1, |
1227ba74 | 4394 | lval, non_constant_p, overflow_p, |
00f21715 | 4395 | jump_target); |
09b42213 | 4396 | } |
4397 | } | |
4398 | break; | |
4399 | ||
4400 | case POINTER_PLUS_EXPR: | |
57e83b58 | 4401 | case POINTER_DIFF_EXPR: |
09b42213 | 4402 | case PLUS_EXPR: |
4403 | case MINUS_EXPR: | |
4404 | case MULT_EXPR: | |
4405 | case TRUNC_DIV_EXPR: | |
4406 | case CEIL_DIV_EXPR: | |
4407 | case FLOOR_DIV_EXPR: | |
4408 | case ROUND_DIV_EXPR: | |
4409 | case TRUNC_MOD_EXPR: | |
4410 | case CEIL_MOD_EXPR: | |
4411 | case ROUND_MOD_EXPR: | |
4412 | case RDIV_EXPR: | |
4413 | case EXACT_DIV_EXPR: | |
4414 | case MIN_EXPR: | |
4415 | case MAX_EXPR: | |
4416 | case LSHIFT_EXPR: | |
4417 | case RSHIFT_EXPR: | |
4418 | case LROTATE_EXPR: | |
4419 | case RROTATE_EXPR: | |
4420 | case BIT_IOR_EXPR: | |
4421 | case BIT_XOR_EXPR: | |
4422 | case BIT_AND_EXPR: | |
4423 | case TRUTH_XOR_EXPR: | |
4424 | case LT_EXPR: | |
4425 | case LE_EXPR: | |
4426 | case GT_EXPR: | |
4427 | case GE_EXPR: | |
4428 | case EQ_EXPR: | |
4429 | case NE_EXPR: | |
4430 | case UNORDERED_EXPR: | |
4431 | case ORDERED_EXPR: | |
4432 | case UNLT_EXPR: | |
4433 | case UNLE_EXPR: | |
4434 | case UNGT_EXPR: | |
4435 | case UNGE_EXPR: | |
4436 | case UNEQ_EXPR: | |
4437 | case LTGT_EXPR: | |
4438 | case RANGE_EXPR: | |
4439 | case COMPLEX_EXPR: | |
1227ba74 | 4440 | r = cxx_eval_binary_expression (ctx, t, lval, |
09b42213 | 4441 | non_constant_p, overflow_p); |
4442 | break; | |
4443 | ||
4444 | /* fold can introduce non-IF versions of these; still treat them as | |
4445 | short-circuiting. */ | |
4446 | case TRUTH_AND_EXPR: | |
4447 | case TRUTH_ANDIF_EXPR: | |
cf72f34d | 4448 | r = cxx_eval_logical_expression (ctx, t, boolean_false_node, |
09b42213 | 4449 | boolean_true_node, |
1227ba74 | 4450 | lval, |
09b42213 | 4451 | non_constant_p, overflow_p); |
4452 | break; | |
4453 | ||
4454 | case TRUTH_OR_EXPR: | |
4455 | case TRUTH_ORIF_EXPR: | |
cf72f34d | 4456 | r = cxx_eval_logical_expression (ctx, t, boolean_true_node, |
09b42213 | 4457 | boolean_false_node, |
1227ba74 | 4458 | lval, |
09b42213 | 4459 | non_constant_p, overflow_p); |
4460 | break; | |
4461 | ||
4462 | case ARRAY_REF: | |
1227ba74 | 4463 | r = cxx_eval_array_reference (ctx, t, lval, |
09b42213 | 4464 | non_constant_p, overflow_p); |
4465 | break; | |
4466 | ||
4467 | case COMPONENT_REF: | |
4468 | if (is_overloaded_fn (t)) | |
4469 | { | |
4470 | /* We can only get here in checking mode via | |
4471 | build_non_dependent_expr, because any expression that | |
4472 | calls or takes the address of the function will have | |
4473 | pulled a FUNCTION_DECL out of the COMPONENT_REF. */ | |
f83e6885 | 4474 | gcc_checking_assert (ctx->quiet || errorcount); |
09b42213 | 4475 | *non_constant_p = true; |
4476 | return t; | |
4477 | } | |
1227ba74 | 4478 | r = cxx_eval_component_reference (ctx, t, lval, |
09b42213 | 4479 | non_constant_p, overflow_p); |
4480 | break; | |
4481 | ||
4482 | case BIT_FIELD_REF: | |
1227ba74 | 4483 | r = cxx_eval_bit_field_ref (ctx, t, lval, |
09b42213 | 4484 | non_constant_p, overflow_p); |
4485 | break; | |
4486 | ||
4487 | case COND_EXPR: | |
2a2770c6 | 4488 | if (jump_target && *jump_target) |
4489 | { | |
4490 | /* When jumping to a label, the label might be either in the | |
4491 | then or else blocks, so process then block first in skipping | |
4492 | mode first, and if we are still in the skipping mode at its end, | |
4493 | process the else block too. */ | |
4494 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
4495 | lval, non_constant_p, overflow_p, | |
4496 | jump_target); | |
4497 | if (*jump_target) | |
4498 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
4499 | lval, non_constant_p, overflow_p, | |
4500 | jump_target); | |
4501 | break; | |
4502 | } | |
1227ba74 | 4503 | r = cxx_eval_conditional_expression (ctx, t, lval, |
00f21715 | 4504 | non_constant_p, overflow_p, |
4505 | jump_target); | |
09b42213 | 4506 | break; |
31595caf | 4507 | case VEC_COND_EXPR: |
4508 | r = cxx_eval_vector_conditional_expression (ctx, t, non_constant_p, | |
4509 | overflow_p); | |
4510 | break; | |
09b42213 | 4511 | |
4512 | case CONSTRUCTOR: | |
1a3631bc | 4513 | if (TREE_CONSTANT (t)) |
58b0f9ce | 4514 | { |
4515 | /* Don't re-process a constant CONSTRUCTOR, but do fold it to | |
4516 | VECTOR_CST if applicable. */ | |
4517 | /* FIXME after GCC 6 branches, make the verify unconditional. */ | |
4518 | if (CHECKING_P) | |
4519 | verify_constructor_flags (t); | |
4520 | else | |
4521 | recompute_constructor_flags (t); | |
4522 | if (TREE_CONSTANT (t)) | |
4523 | return fold (t); | |
4524 | } | |
1227ba74 | 4525 | r = cxx_eval_bare_aggregate (ctx, t, lval, |
09b42213 | 4526 | non_constant_p, overflow_p); |
4527 | break; | |
4528 | ||
4529 | case VEC_INIT_EXPR: | |
4530 | /* We can get this in a defaulted constructor for a class with a | |
4531 | non-static data member of array type. Either the initializer will | |
4532 | be NULL, meaning default-initialization, or it will be an lvalue | |
4533 | or xvalue of the same type, meaning direct-initialization from the | |
4534 | corresponding member. */ | |
1227ba74 | 4535 | r = cxx_eval_vec_init (ctx, t, lval, |
09b42213 | 4536 | non_constant_p, overflow_p); |
4537 | break; | |
4538 | ||
4539 | case FMA_EXPR: | |
4540 | case VEC_PERM_EXPR: | |
1227ba74 | 4541 | r = cxx_eval_trinary_expression (ctx, t, lval, |
09b42213 | 4542 | non_constant_p, overflow_p); |
4543 | break; | |
4544 | ||
4545 | case CONVERT_EXPR: | |
4546 | case VIEW_CONVERT_EXPR: | |
4547 | case NOP_EXPR: | |
d2c63826 | 4548 | case UNARY_PLUS_EXPR: |
09b42213 | 4549 | { |
4550 | tree oldop = TREE_OPERAND (t, 0); | |
d2c63826 | 4551 | |
cf72f34d | 4552 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4553 | lval, |
b2a43197 | 4554 | non_constant_p, overflow_p); |
09b42213 | 4555 | if (*non_constant_p) |
4556 | return t; | |
f16ed232 | 4557 | tree type = TREE_TYPE (t); |
4558 | if (TREE_CODE (op) == PTRMEM_CST | |
4559 | && !TYPE_PTRMEM_P (type)) | |
4560 | op = cplus_expand_constant (op); | |
6a9b35ef | 4561 | if (TREE_CODE (op) == PTRMEM_CST && tcode == NOP_EXPR) |
4562 | { | |
4563 | if (same_type_ignoring_top_level_qualifiers_p (type, | |
0a8a2108 | 4564 | TREE_TYPE (op)) |
4565 | || can_convert_qual (type, op)) | |
19d56e62 | 4566 | return cp_fold_convert (type, op); |
6a9b35ef | 4567 | else |
4568 | { | |
4569 | if (!ctx->quiet) | |
4570 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
ea034e2c | 4571 | "a reinterpret_cast is not a constant expression"); |
6a9b35ef | 4572 | *non_constant_p = true; |
4573 | return t; | |
4574 | } | |
4575 | } | |
cb768824 | 4576 | |
4577 | if (POINTER_TYPE_P (type) && TREE_CODE (op) == INTEGER_CST) | |
09b42213 | 4578 | { |
cb768824 | 4579 | if (integer_zerop (op)) |
4580 | { | |
4581 | if (TREE_CODE (type) == REFERENCE_TYPE) | |
4582 | { | |
4583 | if (!ctx->quiet) | |
4584 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4585 | "dereferencing a null pointer"); | |
4586 | *non_constant_p = true; | |
4587 | return t; | |
4588 | } | |
4589 | else if (TREE_CODE (TREE_TYPE (op)) == POINTER_TYPE) | |
4590 | { | |
4591 | tree from = TREE_TYPE (op); | |
4592 | ||
4593 | if (!can_convert (type, from, tf_none)) | |
4594 | { | |
4595 | if (!ctx->quiet) | |
4596 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4597 | "conversion of %qT null pointer to %qT " | |
4598 | "is not a constant expression", | |
4599 | from, type); | |
4600 | *non_constant_p = true; | |
4601 | return t; | |
4602 | } | |
4603 | } | |
4604 | } | |
4605 | else | |
4606 | { | |
4607 | /* This detects for example: | |
4608 | reinterpret_cast<void*>(sizeof 0) | |
4609 | */ | |
4610 | if (!ctx->quiet) | |
4611 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4612 | "%<reinterpret_cast<%T>(%E)%> is not " | |
ea034e2c | 4613 | "a constant expression", |
cb768824 | 4614 | type, op); |
4615 | *non_constant_p = true; | |
4616 | return t; | |
4617 | } | |
09b42213 | 4618 | } |
d2c63826 | 4619 | if (op == oldop && tcode != UNARY_PLUS_EXPR) |
09b42213 | 4620 | /* We didn't fold at the top so we could check for ptr-int |
4621 | conversion. */ | |
4622 | return fold (t); | |
d2c63826 | 4623 | if (tcode == UNARY_PLUS_EXPR) |
4624 | r = fold_convert (TREE_TYPE (t), op); | |
4625 | else | |
4626 | r = fold_build1 (tcode, type, op); | |
09b42213 | 4627 | /* Conversion of an out-of-range value has implementation-defined |
4628 | behavior; the language considers it different from arithmetic | |
4629 | overflow, which is undefined. */ | |
4630 | if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op)) | |
4631 | TREE_OVERFLOW (r) = false; | |
4632 | } | |
4633 | break; | |
4634 | ||
4635 | case EMPTY_CLASS_EXPR: | |
4636 | /* This is good enough for a function argument that might not get | |
4637 | used, and they can't do anything with it, so just return it. */ | |
4638 | return t; | |
4639 | ||
9c96033c | 4640 | case STATEMENT_LIST: |
00f21715 | 4641 | new_ctx = *ctx; |
4642 | new_ctx.ctor = new_ctx.object = NULL_TREE; | |
f83e6885 | 4643 | return cxx_eval_statement_list (&new_ctx, t, |
00f21715 | 4644 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4645 | |
4646 | case BIND_EXPR: | |
4647 | return cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t), | |
1227ba74 | 4648 | lval, |
00f21715 | 4649 | non_constant_p, overflow_p, |
4650 | jump_target); | |
9c96033c | 4651 | |
09b42213 | 4652 | case PREINCREMENT_EXPR: |
4653 | case POSTINCREMENT_EXPR: | |
4654 | case PREDECREMENT_EXPR: | |
4655 | case POSTDECREMENT_EXPR: | |
f83e6885 | 4656 | return cxx_eval_increment_expression (ctx, t, |
1227ba74 | 4657 | lval, non_constant_p, overflow_p); |
9c96033c | 4658 | |
4659 | case LAMBDA_EXPR: | |
09b42213 | 4660 | case NEW_EXPR: |
4661 | case VEC_NEW_EXPR: | |
4662 | case DELETE_EXPR: | |
4663 | case VEC_DELETE_EXPR: | |
4664 | case THROW_EXPR: | |
09b42213 | 4665 | case MODOP_EXPR: |
4666 | /* GCC internal stuff. */ | |
4667 | case VA_ARG_EXPR: | |
4668 | case OBJ_TYPE_REF: | |
09b42213 | 4669 | case NON_DEPENDENT_EXPR: |
4670 | case BASELINK: | |
09b42213 | 4671 | case OFFSET_REF: |
f83e6885 | 4672 | if (!ctx->quiet) |
09b42213 | 4673 | error_at (EXPR_LOC_OR_LOC (t, input_location), |
ea034e2c | 4674 | "expression %qE is not a constant expression", t); |
09b42213 | 4675 | *non_constant_p = true; |
4676 | break; | |
4677 | ||
cf72f34d | 4678 | case PLACEHOLDER_EXPR: |
85de9604 | 4679 | /* Use of the value or address of the current object. */ |
4680 | if (tree ctor = lookup_placeholder (ctx, lval, TREE_TYPE (t))) | |
4681 | return cxx_eval_constant_expression (ctx, ctor, lval, | |
4682 | non_constant_p, overflow_p); | |
4683 | /* A placeholder without a referent. We can get here when | |
4684 | checking whether NSDMIs are noexcept, or in massage_init_elt; | |
4685 | just say it's non-constant for now. */ | |
4686 | gcc_assert (ctx->quiet); | |
4687 | *non_constant_p = true; | |
cf72f34d | 4688 | break; |
4689 | ||
cf03ba19 | 4690 | case EXIT_EXPR: |
4691 | { | |
4692 | tree cond = TREE_OPERAND (t, 0); | |
4693 | cond = cxx_eval_constant_expression (ctx, cond, /*lval*/false, | |
4694 | non_constant_p, overflow_p); | |
4695 | VERIFY_CONSTANT (cond); | |
4696 | if (integer_nonzerop (cond)) | |
4697 | *jump_target = t; | |
4698 | } | |
4699 | break; | |
4700 | ||
9c96033c | 4701 | case GOTO_EXPR: |
00f21715 | 4702 | *jump_target = TREE_OPERAND (t, 0); |
d29e4e8c | 4703 | gcc_assert (breaks (jump_target) || continues (jump_target) |
4704 | /* Allow for jumping to a cdtor_label. */ | |
4705 | || returns (jump_target)); | |
00f21715 | 4706 | break; |
4707 | ||
9c96033c | 4708 | case LOOP_EXPR: |
f83e6885 | 4709 | cxx_eval_loop_expr (ctx, t, |
00f21715 | 4710 | non_constant_p, overflow_p, jump_target); |
4711 | break; | |
4712 | ||
9c96033c | 4713 | case SWITCH_EXPR: |
f83e6885 | 4714 | cxx_eval_switch_expr (ctx, t, |
00f21715 | 4715 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4716 | break; |
4717 | ||
56c12fd4 | 4718 | case REQUIRES_EXPR: |
4719 | /* It's possible to get a requires-expression in a constant | |
4720 | expression. For example: | |
4721 | ||
4722 | template<typename T> concept bool C() { | |
4723 | return requires (T t) { t; }; | |
4724 | } | |
4725 | ||
4726 | template<typename T> requires !C<T>() void f(T); | |
4727 | ||
4728 | Normalization leaves f with the associated constraint | |
4729 | '!requires (T t) { ... }' which is not transformed into | |
4730 | a constraint. */ | |
4731 | if (!processing_template_decl) | |
4732 | return evaluate_constraint_expression (t, NULL_TREE); | |
4733 | else | |
4734 | *non_constant_p = true; | |
4735 | return t; | |
4736 | ||
24c6ee98 | 4737 | case ANNOTATE_EXPR: |
24c6ee98 | 4738 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
4739 | lval, | |
4740 | non_constant_p, overflow_p, | |
4741 | jump_target); | |
4742 | break; | |
4743 | ||
7285637a | 4744 | case USING_STMT: |
4745 | r = void_node; | |
4746 | break; | |
4747 | ||
09b42213 | 4748 | default: |
b9a3af23 | 4749 | if (STATEMENT_CODE_P (TREE_CODE (t))) |
4750 | { | |
4751 | /* This function doesn't know how to deal with pre-genericize | |
4752 | statements; this can only happen with statement-expressions, | |
4753 | so for now just fail. */ | |
4754 | if (!ctx->quiet) | |
4755 | error_at (EXPR_LOCATION (t), | |
ea034e2c | 4756 | "statement is not a constant expression"); |
b9a3af23 | 4757 | } |
4758 | else | |
4759 | internal_error ("unexpected expression %qE of kind %s", t, | |
4760 | get_tree_code_name (TREE_CODE (t))); | |
09b42213 | 4761 | *non_constant_p = true; |
4762 | break; | |
4763 | } | |
4764 | ||
4765 | if (r == error_mark_node) | |
4766 | *non_constant_p = true; | |
4767 | ||
4768 | if (*non_constant_p) | |
4769 | return t; | |
4770 | else | |
4771 | return r; | |
4772 | } | |
4773 | ||
4774 | static tree | |
cf72f34d | 4775 | cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, |
2055d27a | 4776 | bool strict = true, tree object = NULL_TREE) |
09b42213 | 4777 | { |
c300fe28 | 4778 | auto_timevar time (TV_CONSTEXPR); |
4779 | ||
09b42213 | 4780 | bool non_constant_p = false; |
4781 | bool overflow_p = false; | |
cf72f34d | 4782 | hash_map<tree,tree> map; |
2631cb67 | 4783 | |
2a2770c6 | 4784 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, NULL, NULL, |
2631cb67 | 4785 | allow_non_constant, strict }; |
4786 | ||
cf72f34d | 4787 | tree type = initialized_type (t); |
cf72f34d | 4788 | tree r = t; |
4789 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) | |
4790 | { | |
4791 | /* In C++14 an NSDMI can participate in aggregate initialization, | |
4792 | and can refer to the address of the object being initialized, so | |
4793 | we need to pass in the relevant VAR_DECL if we want to do the | |
4794 | evaluation in a single pass. The evaluation will dynamically | |
4795 | update ctx.values for the VAR_DECL. We use the same strategy | |
4796 | for C++11 constexpr constructors that refer to the object being | |
4797 | initialized. */ | |
4798 | ctx.ctor = build_constructor (type, NULL); | |
4799 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctx.ctor) = true; | |
9c96033c | 4800 | if (!object) |
4801 | { | |
4802 | if (TREE_CODE (t) == TARGET_EXPR) | |
4803 | object = TARGET_EXPR_SLOT (t); | |
4804 | else if (TREE_CODE (t) == AGGR_INIT_EXPR) | |
4805 | object = AGGR_INIT_EXPR_SLOT (t); | |
4806 | } | |
cf72f34d | 4807 | ctx.object = object; |
4808 | if (object) | |
4809 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
4810 | (type, TREE_TYPE (object))); | |
4811 | if (object && DECL_P (object)) | |
4812 | map.put (object, ctx.ctor); | |
4813 | if (TREE_CODE (r) == TARGET_EXPR) | |
4814 | /* Avoid creating another CONSTRUCTOR when we expand the | |
4815 | TARGET_EXPR. */ | |
4816 | r = TARGET_EXPR_INITIAL (r); | |
4817 | } | |
4818 | ||
f83e6885 | 4819 | r = cxx_eval_constant_expression (&ctx, r, |
b2a43197 | 4820 | false, &non_constant_p, &overflow_p); |
09b42213 | 4821 | |
4822 | verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); | |
4823 | ||
bbcc9042 | 4824 | /* Mutable logic is a bit tricky: we want to allow initialization of |
4825 | constexpr variables with mutable members, but we can't copy those | |
4826 | members to another constexpr variable. */ | |
4827 | if (TREE_CODE (r) == CONSTRUCTOR | |
4828 | && CONSTRUCTOR_MUTABLE_POISON (r)) | |
09b42213 | 4829 | { |
09b42213 | 4830 | if (!allow_non_constant) |
bbcc9042 | 4831 | error ("%qE is not a constant expression because it refers to " |
4832 | "mutable subobjects of %qT", t, type); | |
09b42213 | 4833 | non_constant_p = true; |
4834 | } | |
4835 | ||
c6d97004 | 4836 | if (TREE_CODE (r) == CONSTRUCTOR |
4837 | && CONSTRUCTOR_NO_IMPLICIT_ZERO (r)) | |
4838 | { | |
4839 | if (!allow_non_constant) | |
4840 | error ("%qE is not a constant expression because it refers to " | |
4841 | "an incompletely initialized variable", t); | |
4842 | TREE_CONSTANT (r) = false; | |
4843 | non_constant_p = true; | |
4844 | } | |
4845 | ||
09b42213 | 4846 | /* Technically we should check this for all subexpressions, but that |
4847 | runs into problems with our internal representation of pointer | |
4848 | subtraction and the 5.19 rules are still in flux. */ | |
4849 | if (CONVERT_EXPR_CODE_P (TREE_CODE (r)) | |
4850 | && ARITHMETIC_TYPE_P (TREE_TYPE (r)) | |
4851 | && TREE_CODE (TREE_OPERAND (r, 0)) == ADDR_EXPR) | |
4852 | { | |
4853 | if (!allow_non_constant) | |
4854 | error ("conversion from pointer type %qT " | |
ea034e2c | 4855 | "to arithmetic type %qT in a constant expression", |
09b42213 | 4856 | TREE_TYPE (TREE_OPERAND (r, 0)), TREE_TYPE (r)); |
4857 | non_constant_p = true; | |
4858 | } | |
4859 | ||
4860 | if (!non_constant_p && overflow_p) | |
4861 | non_constant_p = true; | |
4862 | ||
c6c0523b | 4863 | /* Unshare the result unless it's a CONSTRUCTOR in which case it's already |
4864 | unshared. */ | |
4865 | bool should_unshare = true; | |
4866 | if (r == t || TREE_CODE (r) == CONSTRUCTOR) | |
4867 | should_unshare = false; | |
4868 | ||
09b42213 | 4869 | if (non_constant_p && !allow_non_constant) |
4870 | return error_mark_node; | |
4871 | else if (non_constant_p && TREE_CONSTANT (r)) | |
4872 | { | |
1d29f4ea | 4873 | /* This isn't actually constant, so unset TREE_CONSTANT. |
4874 | Don't clear TREE_CONSTANT on ADDR_EXPR, as the middle-end requires | |
4875 | it to be set if it is invariant address, even when it is not | |
4876 | a valid C++ constant expression. Wrap it with a NOP_EXPR | |
4877 | instead. */ | |
4878 | if (EXPR_P (r) && TREE_CODE (r) != ADDR_EXPR) | |
09b42213 | 4879 | r = copy_node (r); |
4880 | else if (TREE_CODE (r) == CONSTRUCTOR) | |
4881 | r = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (r), r); | |
4882 | else | |
4883 | r = build_nop (TREE_TYPE (r), r); | |
4884 | TREE_CONSTANT (r) = false; | |
4885 | } | |
4886 | else if (non_constant_p || r == t) | |
4887 | return t; | |
4888 | ||
c6c0523b | 4889 | if (should_unshare) |
4890 | r = unshare_expr (r); | |
4891 | ||
09b42213 | 4892 | if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r))) |
4893 | { | |
4894 | if (TREE_CODE (t) == TARGET_EXPR | |
4895 | && TARGET_EXPR_INITIAL (t) == r) | |
4896 | return t; | |
4897 | else | |
4898 | { | |
4899 | r = get_target_expr (r); | |
4900 | TREE_CONSTANT (r) = true; | |
4901 | return r; | |
4902 | } | |
4903 | } | |
4904 | else | |
4905 | return r; | |
4906 | } | |
4907 | ||
4908 | /* Returns true if T is a valid subexpression of a constant expression, | |
4909 | even if it isn't itself a constant expression. */ | |
4910 | ||
4911 | bool | |
4912 | is_sub_constant_expr (tree t) | |
4913 | { | |
4914 | bool non_constant_p = false; | |
4915 | bool overflow_p = false; | |
cf72f34d | 4916 | hash_map <tree, tree> map; |
2631cb67 | 4917 | |
2a2770c6 | 4918 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, NULL, NULL, true, true }; |
2631cb67 | 4919 | |
f83e6885 | 4920 | cxx_eval_constant_expression (&ctx, t, false, &non_constant_p, |
b2a43197 | 4921 | &overflow_p); |
09b42213 | 4922 | return !non_constant_p && !overflow_p; |
4923 | } | |
4924 | ||
4925 | /* If T represents a constant expression returns its reduced value. | |
4926 | Otherwise return error_mark_node. If T is dependent, then | |
4927 | return NULL. */ | |
4928 | ||
4929 | tree | |
cf72f34d | 4930 | cxx_constant_value (tree t, tree decl) |
09b42213 | 4931 | { |
2055d27a | 4932 | return cxx_eval_outermost_constant_expr (t, false, true, decl); |
09b42213 | 4933 | } |
4934 | ||
d2c63826 | 4935 | /* Helper routine for fold_simple function. Either return simplified |
4936 | expression T, otherwise NULL_TREE. | |
4937 | In contrast to cp_fully_fold, and to maybe_constant_value, we try to fold | |
4938 | even if we are within template-declaration. So be careful on call, as in | |
4939 | such case types can be undefined. */ | |
4940 | ||
4941 | static tree | |
4942 | fold_simple_1 (tree t) | |
4943 | { | |
4944 | tree op1; | |
4945 | enum tree_code code = TREE_CODE (t); | |
4946 | ||
4947 | switch (code) | |
4948 | { | |
4949 | case INTEGER_CST: | |
4950 | case REAL_CST: | |
4951 | case VECTOR_CST: | |
4952 | case FIXED_CST: | |
4953 | case COMPLEX_CST: | |
4954 | return t; | |
4955 | ||
4956 | case SIZEOF_EXPR: | |
4957 | return fold_sizeof_expr (t); | |
4958 | ||
4959 | case ABS_EXPR: | |
4960 | case CONJ_EXPR: | |
4961 | case REALPART_EXPR: | |
4962 | case IMAGPART_EXPR: | |
4963 | case NEGATE_EXPR: | |
4964 | case BIT_NOT_EXPR: | |
4965 | case TRUTH_NOT_EXPR: | |
4966 | case NOP_EXPR: | |
4967 | case VIEW_CONVERT_EXPR: | |
4968 | case CONVERT_EXPR: | |
4969 | case FLOAT_EXPR: | |
4970 | case FIX_TRUNC_EXPR: | |
4971 | case FIXED_CONVERT_EXPR: | |
4972 | case ADDR_SPACE_CONVERT_EXPR: | |
4973 | ||
4974 | op1 = TREE_OPERAND (t, 0); | |
4975 | ||
4976 | t = const_unop (code, TREE_TYPE (t), op1); | |
4977 | if (!t) | |
4978 | return NULL_TREE; | |
4979 | ||
4980 | if (CONVERT_EXPR_CODE_P (code) | |
4981 | && TREE_OVERFLOW_P (t) && !TREE_OVERFLOW_P (op1)) | |
4982 | TREE_OVERFLOW (t) = false; | |
4983 | return t; | |
4984 | ||
4985 | default: | |
4986 | return NULL_TREE; | |
4987 | } | |
4988 | } | |
4989 | ||
4990 | /* If T is a simple constant expression, returns its simplified value. | |
6fe5fea9 | 4991 | Otherwise returns T. In contrast to maybe_constant_value we |
d2c63826 | 4992 | simplify only few operations on constant-expressions, and we don't |
4993 | try to simplify constexpressions. */ | |
4994 | ||
4995 | tree | |
4996 | fold_simple (tree t) | |
4997 | { | |
d2c63826 | 4998 | if (processing_template_decl) |
4999 | return t; | |
5000 | ||
6fe5fea9 | 5001 | tree r = fold_simple_1 (t); |
5002 | if (r) | |
5003 | return r; | |
d2c63826 | 5004 | |
6fe5fea9 | 5005 | return t; |
d2c63826 | 5006 | } |
5007 | ||
09b42213 | 5008 | /* If T is a constant expression, returns its reduced value. |
5009 | Otherwise, if T does not have TREE_CONSTANT set, returns T. | |
5010 | Otherwise, returns a version of T without TREE_CONSTANT. */ | |
5011 | ||
b601ad30 | 5012 | static GTY((deletable)) hash_map<tree, tree> *cv_cache; |
5013 | ||
5014 | tree | |
5015 | maybe_constant_value (tree t, tree decl) | |
09b42213 | 5016 | { |
5017 | tree r; | |
5018 | ||
7e1f8be4 | 5019 | if (!is_nondependent_constant_expression (t)) |
09b42213 | 5020 | { |
5021 | if (TREE_OVERFLOW_P (t)) | |
5022 | { | |
5023 | t = build_nop (TREE_TYPE (t), t); | |
5024 | TREE_CONSTANT (t) = false; | |
5025 | } | |
5026 | return t; | |
5027 | } | |
b601ad30 | 5028 | else if (CONSTANT_CLASS_P (t)) |
5029 | /* No caching or evaluation needed. */ | |
5030 | return t; | |
5031 | ||
5032 | if (cv_cache == NULL) | |
5033 | cv_cache = hash_map<tree, tree>::create_ggc (101); | |
5034 | if (tree *cached = cv_cache->get (t)) | |
5035 | return *cached; | |
09b42213 | 5036 | |
2055d27a | 5037 | r = cxx_eval_outermost_constant_expr (t, true, true, decl); |
5e8689fb | 5038 | gcc_checking_assert (r == t |
5039 | || CONVERT_EXPR_P (t) | |
5040 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
5041 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
5042 | || !cp_tree_equal (r, t)); | |
b601ad30 | 5043 | cv_cache->put (t, r); |
09b42213 | 5044 | return r; |
5045 | } | |
5046 | ||
2a655a4c | 5047 | /* Dispose of the whole CV_CACHE. */ |
5048 | ||
5049 | static void | |
5050 | clear_cv_cache (void) | |
5051 | { | |
5052 | if (cv_cache != NULL) | |
5053 | cv_cache->empty (); | |
5054 | } | |
5055 | ||
f553d9f8 | 5056 | /* Dispose of the whole CV_CACHE and FOLD_CACHE. */ |
a0c919f7 | 5057 | |
5058 | void | |
f553d9f8 | 5059 | clear_cv_and_fold_caches (void) |
a0c919f7 | 5060 | { |
2a655a4c | 5061 | clear_cv_cache (); |
f553d9f8 | 5062 | clear_fold_cache (); |
a0c919f7 | 5063 | } |
5064 | ||
21131a05 | 5065 | /* Like maybe_constant_value but first fully instantiate the argument. |
5066 | ||
5067 | Note: this is equivalent to instantiate_non_dependent_expr_sfinae | |
5068 | (t, tf_none) followed by maybe_constant_value but is more efficient, | |
5069 | because calls instantiation_dependent_expression_p and | |
5070 | potential_constant_expression at most once. */ | |
5071 | ||
5072 | tree | |
5073 | fold_non_dependent_expr (tree t) | |
5074 | { | |
5075 | if (t == NULL_TREE) | |
5076 | return NULL_TREE; | |
5077 | ||
5078 | /* If we're in a template, but T isn't value dependent, simplify | |
5079 | it. We're supposed to treat: | |
5080 | ||
5081 | template <typename T> void f(T[1 + 1]); | |
5082 | template <typename T> void f(T[2]); | |
5083 | ||
5084 | as two declarations of the same function, for example. */ | |
5085 | if (processing_template_decl) | |
5086 | { | |
7e1f8be4 | 5087 | if (is_nondependent_constant_expression (t)) |
21131a05 | 5088 | { |
c8a9f04c | 5089 | processing_template_decl_sentinel s; |
5090 | t = instantiate_non_dependent_expr_internal (t, tf_none); | |
21131a05 | 5091 | |
5092 | if (type_unknown_p (t) | |
5093 | || BRACE_ENCLOSED_INITIALIZER_P (t)) | |
5094 | { | |
5095 | if (TREE_OVERFLOW_P (t)) | |
5096 | { | |
5097 | t = build_nop (TREE_TYPE (t), t); | |
5098 | TREE_CONSTANT (t) = false; | |
5099 | } | |
5100 | return t; | |
5101 | } | |
5102 | ||
2055d27a | 5103 | tree r = cxx_eval_outermost_constant_expr (t, true, true, NULL_TREE); |
21131a05 | 5104 | /* cp_tree_equal looks through NOPs, so allow them. */ |
5e8689fb | 5105 | gcc_checking_assert (r == t |
5106 | || CONVERT_EXPR_P (t) | |
5107 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
5108 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
5109 | || !cp_tree_equal (r, t)); | |
21131a05 | 5110 | return r; |
5111 | } | |
5112 | else if (TREE_OVERFLOW_P (t)) | |
5113 | { | |
5114 | t = build_nop (TREE_TYPE (t), t); | |
5115 | TREE_CONSTANT (t) = false; | |
5116 | } | |
5117 | return t; | |
5118 | } | |
5119 | ||
5120 | return maybe_constant_value (t); | |
5121 | } | |
5122 | ||
09b42213 | 5123 | /* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather |
5124 | than wrapped in a TARGET_EXPR. */ | |
5125 | ||
0c703e14 | 5126 | static tree |
5127 | maybe_constant_init_1 (tree t, tree decl, bool allow_non_constant) | |
09b42213 | 5128 | { |
d2c63826 | 5129 | if (!t) |
5130 | return t; | |
09b42213 | 5131 | if (TREE_CODE (t) == EXPR_STMT) |
5132 | t = TREE_OPERAND (t, 0); | |
5133 | if (TREE_CODE (t) == CONVERT_EXPR | |
5134 | && VOID_TYPE_P (TREE_TYPE (t))) | |
5135 | t = TREE_OPERAND (t, 0); | |
9c96033c | 5136 | if (TREE_CODE (t) == INIT_EXPR) |
5137 | t = TREE_OPERAND (t, 1); | |
c6d97004 | 5138 | if (TREE_CODE (t) == TARGET_EXPR) |
5139 | t = TARGET_EXPR_INITIAL (t); | |
7e1f8be4 | 5140 | if (!is_nondependent_static_init_expression (t)) |
2055d27a | 5141 | /* Don't try to evaluate it. */; |
0c703e14 | 5142 | else if (CONSTANT_CLASS_P (t) && allow_non_constant) |
b601ad30 | 5143 | /* No evaluation needed. */; |
2055d27a | 5144 | else |
0c703e14 | 5145 | t = cxx_eval_outermost_constant_expr (t, allow_non_constant, false, decl); |
09b42213 | 5146 | if (TREE_CODE (t) == TARGET_EXPR) |
5147 | { | |
5148 | tree init = TARGET_EXPR_INITIAL (t); | |
5149 | if (TREE_CODE (init) == CONSTRUCTOR) | |
5150 | t = init; | |
5151 | } | |
5152 | return t; | |
5153 | } | |
5154 | ||
0c703e14 | 5155 | /* Wrapper for maybe_constant_init_1 which permits non constants. */ |
5156 | ||
5157 | tree | |
5158 | maybe_constant_init (tree t, tree decl) | |
5159 | { | |
5160 | return maybe_constant_init_1 (t, decl, true); | |
5161 | } | |
5162 | ||
5163 | /* Wrapper for maybe_constant_init_1 which does not permit non constants. */ | |
5164 | ||
5165 | tree | |
5166 | cxx_constant_init (tree t, tree decl) | |
5167 | { | |
5168 | return maybe_constant_init_1 (t, decl, false); | |
5169 | } | |
5170 | ||
09b42213 | 5171 | #if 0 |
5172 | /* FIXME see ADDR_EXPR section in potential_constant_expression_1. */ | |
5173 | /* Return true if the object referred to by REF has automatic or thread | |
5174 | local storage. */ | |
5175 | ||
5176 | enum { ck_ok, ck_bad, ck_unknown }; | |
5177 | static int | |
5178 | check_automatic_or_tls (tree ref) | |
5179 | { | |
3754d046 | 5180 | machine_mode mode; |
81bc0f0f | 5181 | poly_int64 bitsize, bitpos; |
09b42213 | 5182 | tree offset; |
5183 | int volatilep = 0, unsignedp = 0; | |
5184 | tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset, | |
5185 | &mode, &unsignedp, &volatilep, false); | |
5186 | duration_kind dk; | |
5187 | ||
5188 | /* If there isn't a decl in the middle, we don't know the linkage here, | |
5189 | and this isn't a constant expression anyway. */ | |
5190 | if (!DECL_P (decl)) | |
5191 | return ck_unknown; | |
5192 | dk = decl_storage_duration (decl); | |
5193 | return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok; | |
5194 | } | |
5195 | #endif | |
5196 | ||
5197 | /* Return true if T denotes a potentially constant expression. Issue | |
5198 | diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true, | |
7e1f8be4 | 5199 | an lvalue-rvalue conversion is implied. If NOW is true, we want to |
5200 | consider the expression in the current context, independent of constexpr | |
5201 | substitution. | |
09b42213 | 5202 | |
5203 | C++0x [expr.const] used to say | |
5204 | ||
5205 | 6 An expression is a potential constant expression if it is | |
5206 | a constant expression where all occurrences of function | |
5207 | parameters are replaced by arbitrary constant expressions | |
5208 | of the appropriate type. | |
5209 | ||
5210 | 2 A conditional expression is a constant expression unless it | |
5211 | involves one of the following as a potentially evaluated | |
5212 | subexpression (3.2), but subexpressions of logical AND (5.14), | |
5213 | logical OR (5.15), and conditional (5.16) operations that are | |
5214 | not evaluated are not considered. */ | |
5215 | ||
5216 | static bool | |
7e1f8be4 | 5217 | potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, |
2055d27a | 5218 | tsubst_flags_t flags) |
09b42213 | 5219 | { |
7e1f8be4 | 5220 | #define RECUR(T,RV) \ |
5221 | potential_constant_expression_1 ((T), (RV), strict, now, flags) | |
5222 | ||
09b42213 | 5223 | enum { any = false, rval = true }; |
5224 | int i; | |
5225 | tree tmp; | |
5226 | ||
5227 | if (t == error_mark_node) | |
5228 | return false; | |
5229 | if (t == NULL_TREE) | |
5230 | return true; | |
d6a08f5c | 5231 | location_t loc = EXPR_LOC_OR_LOC (t, input_location); |
eade0940 | 5232 | if (TREE_THIS_VOLATILE (t) && !DECL_P (t)) |
09b42213 | 5233 | { |
5234 | if (flags & tf_error) | |
d6a08f5c | 5235 | error_at (loc, "expression %qE has side-effects", t); |
09b42213 | 5236 | return false; |
5237 | } | |
5238 | if (CONSTANT_CLASS_P (t)) | |
5239 | return true; | |
c7282bf2 | 5240 | if (CODE_CONTAINS_STRUCT (TREE_CODE (t), TS_TYPED) |
5241 | && TREE_TYPE (t) == error_mark_node) | |
5242 | return false; | |
09b42213 | 5243 | |
5244 | switch (TREE_CODE (t)) | |
5245 | { | |
5246 | case FUNCTION_DECL: | |
5247 | case BASELINK: | |
5248 | case TEMPLATE_DECL: | |
5249 | case OVERLOAD: | |
5250 | case TEMPLATE_ID_EXPR: | |
5251 | case LABEL_DECL: | |
5252 | case LABEL_EXPR: | |
9c96033c | 5253 | case CASE_LABEL_EXPR: |
09b42213 | 5254 | case CONST_DECL: |
5255 | case SIZEOF_EXPR: | |
5256 | case ALIGNOF_EXPR: | |
5257 | case OFFSETOF_EXPR: | |
5258 | case NOEXCEPT_EXPR: | |
5259 | case TEMPLATE_PARM_INDEX: | |
5260 | case TRAIT_EXPR: | |
5261 | case IDENTIFIER_NODE: | |
5262 | case USERDEF_LITERAL: | |
5263 | /* We can see a FIELD_DECL in a pointer-to-member expression. */ | |
5264 | case FIELD_DECL: | |
d2c63826 | 5265 | case RESULT_DECL: |
09b42213 | 5266 | case USING_DECL: |
9c96033c | 5267 | case USING_STMT: |
cf72f34d | 5268 | case PLACEHOLDER_EXPR: |
9c96033c | 5269 | case BREAK_STMT: |
5270 | case CONTINUE_STMT: | |
56c12fd4 | 5271 | case REQUIRES_EXPR: |
33603066 | 5272 | case STATIC_ASSERT: |
90567983 | 5273 | case DEBUG_BEGIN_STMT: |
09b42213 | 5274 | return true; |
5275 | ||
7e1f8be4 | 5276 | case PARM_DECL: |
5277 | if (now) | |
5278 | { | |
5279 | if (flags & tf_error) | |
5280 | error ("%qE is not a constant expression", t); | |
5281 | return false; | |
5282 | } | |
5283 | return true; | |
5284 | ||
09b42213 | 5285 | case AGGR_INIT_EXPR: |
5286 | case CALL_EXPR: | |
5287 | /* -- an invocation of a function other than a constexpr function | |
5288 | or a constexpr constructor. */ | |
5289 | { | |
5290 | tree fun = get_function_named_in_call (t); | |
5291 | const int nargs = call_expr_nargs (t); | |
5292 | i = 0; | |
5293 | ||
9c96033c | 5294 | if (fun == NULL_TREE) |
5295 | { | |
732905bb | 5296 | /* Reset to allow the function to continue past the end |
5297 | of the block below. Otherwise return early. */ | |
5298 | bool bail = true; | |
5299 | ||
32cf7025 | 5300 | if (TREE_CODE (t) == CALL_EXPR |
5301 | && CALL_EXPR_FN (t) == NULL_TREE) | |
5302 | switch (CALL_EXPR_IFN (t)) | |
5303 | { | |
5304 | /* These should be ignored, they are optimized away from | |
5305 | constexpr functions. */ | |
5306 | case IFN_UBSAN_NULL: | |
5307 | case IFN_UBSAN_BOUNDS: | |
5308 | case IFN_UBSAN_VPTR: | |
3c77f69c | 5309 | case IFN_FALLTHROUGH: |
32cf7025 | 5310 | return true; |
732905bb | 5311 | |
5312 | case IFN_ADD_OVERFLOW: | |
5313 | case IFN_SUB_OVERFLOW: | |
5314 | case IFN_MUL_OVERFLOW: | |
6e1b2ffb | 5315 | case IFN_LAUNDER: |
732905bb | 5316 | bail = false; |
5317 | ||
32cf7025 | 5318 | default: |
5319 | break; | |
5320 | } | |
732905bb | 5321 | |
5322 | if (bail) | |
5323 | { | |
5324 | /* fold_call_expr can't do anything with IFN calls. */ | |
5325 | if (flags & tf_error) | |
d6a08f5c | 5326 | error_at (loc, "call to internal function %qE", t); |
732905bb | 5327 | return false; |
5328 | } | |
9c96033c | 5329 | } |
732905bb | 5330 | |
5331 | if (fun && is_overloaded_fn (fun)) | |
09b42213 | 5332 | { |
5333 | if (TREE_CODE (fun) == FUNCTION_DECL) | |
5334 | { | |
5335 | if (builtin_valid_in_constant_expr_p (fun)) | |
5336 | return true; | |
5337 | if (!DECL_DECLARED_CONSTEXPR_P (fun) | |
5338 | /* Allow any built-in function; if the expansion | |
5339 | isn't constant, we'll deal with that then. */ | |
5340 | && !is_builtin_fn (fun)) | |
5341 | { | |
5342 | if (flags & tf_error) | |
5343 | { | |
5967b28b | 5344 | error_at (loc, "call to non-%<constexpr%> function %qD", |
d6a08f5c | 5345 | fun); |
09b42213 | 5346 | explain_invalid_constexpr_fn (fun); |
5347 | } | |
5348 | return false; | |
5349 | } | |
5350 | /* A call to a non-static member function takes the address | |
5351 | of the object as the first argument. But in a constant | |
5352 | expression the address will be folded away, so look | |
5353 | through it now. */ | |
5354 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
5355 | && !DECL_CONSTRUCTOR_P (fun)) | |
5356 | { | |
5357 | tree x = get_nth_callarg (t, 0); | |
5358 | if (is_this_parameter (x)) | |
cf72f34d | 5359 | return true; |
7e1f8be4 | 5360 | /* Don't require an immediately constant value, as |
5361 | constexpr substitution might not use the value. */ | |
5362 | bool sub_now = false; | |
5363 | if (!potential_constant_expression_1 (x, rval, strict, | |
5364 | sub_now, flags)) | |
09b42213 | 5365 | return false; |
5366 | i = 1; | |
5367 | } | |
5368 | } | |
5369 | else | |
5370 | { | |
2055d27a | 5371 | if (!RECUR (fun, true)) |
09b42213 | 5372 | return false; |
5373 | fun = get_first_fn (fun); | |
5374 | } | |
5375 | /* Skip initial arguments to base constructors. */ | |
5376 | if (DECL_BASE_CONSTRUCTOR_P (fun)) | |
5377 | i = num_artificial_parms_for (fun); | |
5378 | fun = DECL_ORIGIN (fun); | |
5379 | } | |
732905bb | 5380 | else if (fun) |
09b42213 | 5381 | { |
2055d27a | 5382 | if (RECUR (fun, rval)) |
09b42213 | 5383 | /* Might end up being a constant function pointer. */; |
5384 | else | |
5385 | return false; | |
5386 | } | |
5387 | for (; i < nargs; ++i) | |
5388 | { | |
5389 | tree x = get_nth_callarg (t, i); | |
b2742b58 | 5390 | /* In a template, reference arguments haven't been converted to |
5391 | REFERENCE_TYPE and we might not even know if the parameter | |
5392 | is a reference, so accept lvalue constants too. */ | |
5393 | bool rv = processing_template_decl ? any : rval; | |
7e1f8be4 | 5394 | /* Don't require an immediately constant value, as constexpr |
5395 | substitution might not use the value of the argument. */ | |
5396 | bool sub_now = false; | |
5397 | if (!potential_constant_expression_1 (x, rv, strict, | |
5398 | sub_now, flags)) | |
09b42213 | 5399 | return false; |
5400 | } | |
5401 | return true; | |
5402 | } | |
5403 | ||
5404 | case NON_LVALUE_EXPR: | |
5405 | /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to | |
5406 | -- an lvalue of integral type that refers to a non-volatile | |
5407 | const variable or static data member initialized with | |
5408 | constant expressions, or | |
5409 | ||
5410 | -- an lvalue of literal type that refers to non-volatile | |
5411 | object defined with constexpr, or that refers to a | |
5412 | sub-object of such an object; */ | |
2055d27a | 5413 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 5414 | |
5415 | case VAR_DECL: | |
9c8aeb66 | 5416 | if (DECL_HAS_VALUE_EXPR_P (t)) |
297de7bc | 5417 | { |
ba23f9fb | 5418 | if (now && is_capture_proxy_with_ref (t)) |
297de7bc | 5419 | { |
5420 | /* -- in a lambda-expression, a reference to this or to a | |
5421 | variable with automatic storage duration defined outside that | |
5422 | lambda-expression, where the reference would be an | |
5423 | odr-use. */ | |
5424 | if (flags & tf_error) | |
5425 | { | |
5426 | tree cap = DECL_CAPTURED_VARIABLE (t); | |
5427 | error ("lambda capture of %qE is not a constant expression", | |
5428 | cap); | |
5429 | if (!want_rval && decl_constant_var_p (cap)) | |
5430 | inform (input_location, "because it is used as a glvalue"); | |
5431 | } | |
5432 | return false; | |
5433 | } | |
5434 | return RECUR (DECL_VALUE_EXPR (t), rval); | |
5435 | } | |
2055d27a | 5436 | if (want_rval |
33603066 | 5437 | && !var_in_maybe_constexpr_fn (t) |
c7282bf2 | 5438 | && !type_dependent_expression_p (t) |
8d6486e1 | 5439 | && !decl_maybe_constant_var_p (t) |
2055d27a | 5440 | && (strict |
5441 | || !CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (t)) | |
8d6486e1 | 5442 | || (DECL_INITIAL (t) |
5443 | && !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (t))) | |
c7282bf2 | 5444 | && COMPLETE_TYPE_P (TREE_TYPE (t)) |
5445 | && !is_really_empty_class (TREE_TYPE (t))) | |
09b42213 | 5446 | { |
5447 | if (flags & tf_error) | |
5448 | non_const_var_error (t); | |
5449 | return false; | |
5450 | } | |
5451 | return true; | |
5452 | ||
5453 | case NOP_EXPR: | |
5454 | case CONVERT_EXPR: | |
5455 | case VIEW_CONVERT_EXPR: | |
5456 | /* -- a reinterpret_cast. FIXME not implemented, and this rule | |
5457 | may change to something more specific to type-punning (DR 1312). */ | |
5458 | { | |
5459 | tree from = TREE_OPERAND (t, 0); | |
5460 | if (POINTER_TYPE_P (TREE_TYPE (t)) | |
5461 | && TREE_CODE (from) == INTEGER_CST | |
5462 | && !integer_zerop (from)) | |
5463 | { | |
5464 | if (flags & tf_error) | |
d6a08f5c | 5465 | error_at (loc, "reinterpret_cast from integer to pointer"); |
09b42213 | 5466 | return false; |
5467 | } | |
2055d27a | 5468 | return (RECUR (from, TREE_CODE (t) != VIEW_CONVERT_EXPR)); |
09b42213 | 5469 | } |
5470 | ||
cd45162d | 5471 | case ADDRESSOF_EXPR: |
5472 | /* This is like ADDR_EXPR, except it won't form pointer-to-member. */ | |
5473 | t = TREE_OPERAND (t, 0); | |
5474 | goto handle_addr_expr; | |
5475 | ||
09b42213 | 5476 | case ADDR_EXPR: |
5477 | /* -- a unary operator & that is applied to an lvalue that | |
5478 | designates an object with thread or automatic storage | |
5479 | duration; */ | |
5480 | t = TREE_OPERAND (t, 0); | |
5481 | ||
5482 | if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t)) | |
5483 | /* A pointer-to-member constant. */ | |
5484 | return true; | |
5485 | ||
cd45162d | 5486 | handle_addr_expr: |
09b42213 | 5487 | #if 0 |
5488 | /* FIXME adjust when issue 1197 is fully resolved. For now don't do | |
5489 | any checking here, as we might dereference the pointer later. If | |
5490 | we remove this code, also remove check_automatic_or_tls. */ | |
5491 | i = check_automatic_or_tls (t); | |
5492 | if (i == ck_ok) | |
5493 | return true; | |
5494 | if (i == ck_bad) | |
5495 | { | |
5496 | if (flags & tf_error) | |
5497 | error ("address-of an object %qE with thread local or " | |
5498 | "automatic storage is not a constant expression", t); | |
5499 | return false; | |
5500 | } | |
5501 | #endif | |
2055d27a | 5502 | return RECUR (t, any); |
09b42213 | 5503 | |
20b34a56 | 5504 | case REALPART_EXPR: |
5505 | case IMAGPART_EXPR: | |
09b42213 | 5506 | case COMPONENT_REF: |
5507 | case BIT_FIELD_REF: | |
5508 | case ARROW_EXPR: | |
5509 | case OFFSET_REF: | |
5510 | /* -- a class member access unless its postfix-expression is | |
5511 | of literal type or of pointer to literal type. */ | |
5512 | /* This test would be redundant, as it follows from the | |
5513 | postfix-expression being a potential constant expression. */ | |
eade0940 | 5514 | if (type_unknown_p (t)) |
5515 | return true; | |
2055d27a | 5516 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5517 | |
5518 | case EXPR_PACK_EXPANSION: | |
2055d27a | 5519 | return RECUR (PACK_EXPANSION_PATTERN (t), want_rval); |
09b42213 | 5520 | |
5521 | case INDIRECT_REF: | |
5522 | { | |
5523 | tree x = TREE_OPERAND (t, 0); | |
5524 | STRIP_NOPS (x); | |
997bbf70 | 5525 | if (is_this_parameter (x) && !is_capture_proxy (x)) |
09b42213 | 5526 | { |
b7e4a558 | 5527 | if (!var_in_maybe_constexpr_fn (x)) |
09b42213 | 5528 | { |
5529 | if (flags & tf_error) | |
d6a08f5c | 5530 | error_at (loc, "use of %<this%> in a constant expression"); |
09b42213 | 5531 | return false; |
5532 | } | |
09b42213 | 5533 | return true; |
5534 | } | |
2055d27a | 5535 | return RECUR (x, rval); |
09b42213 | 5536 | } |
5537 | ||
9c96033c | 5538 | case STATEMENT_LIST: |
5539 | { | |
5540 | tree_stmt_iterator i; | |
5541 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
5542 | { | |
2055d27a | 5543 | if (!RECUR (tsi_stmt (i), any)) |
9c96033c | 5544 | return false; |
5545 | } | |
5546 | return true; | |
5547 | } | |
5548 | break; | |
5549 | ||
5550 | case MODIFY_EXPR: | |
5551 | if (cxx_dialect < cxx14) | |
5552 | goto fail; | |
2055d27a | 5553 | if (!RECUR (TREE_OPERAND (t, 0), any)) |
9c96033c | 5554 | return false; |
2055d27a | 5555 | if (!RECUR (TREE_OPERAND (t, 1), rval)) |
9c96033c | 5556 | return false; |
5557 | return true; | |
5558 | ||
5559 | case MODOP_EXPR: | |
5560 | if (cxx_dialect < cxx14) | |
5561 | goto fail; | |
2055d27a | 5562 | if (!RECUR (TREE_OPERAND (t, 0), rval)) |
9c96033c | 5563 | return false; |
2055d27a | 5564 | if (!RECUR (TREE_OPERAND (t, 2), rval)) |
9c96033c | 5565 | return false; |
5566 | return true; | |
5567 | ||
9c96033c | 5568 | case DO_STMT: |
2055d27a | 5569 | if (!RECUR (DO_COND (t), rval)) |
9c96033c | 5570 | return false; |
2055d27a | 5571 | if (!RECUR (DO_BODY (t), any)) |
9c96033c | 5572 | return false; |
5573 | return true; | |
5574 | ||
5575 | case FOR_STMT: | |
2055d27a | 5576 | if (!RECUR (FOR_INIT_STMT (t), any)) |
9c96033c | 5577 | return false; |
2055d27a | 5578 | if (!RECUR (FOR_COND (t), rval)) |
9c96033c | 5579 | return false; |
2055d27a | 5580 | if (!RECUR (FOR_EXPR (t), any)) |
9c96033c | 5581 | return false; |
2055d27a | 5582 | if (!RECUR (FOR_BODY (t), any)) |
9c96033c | 5583 | return false; |
5584 | return true; | |
5585 | ||
33603066 | 5586 | case RANGE_FOR_STMT: |
5587 | if (!RECUR (RANGE_FOR_EXPR (t), any)) | |
5588 | return false; | |
5589 | if (!RECUR (RANGE_FOR_BODY (t), any)) | |
5590 | return false; | |
5591 | return true; | |
5592 | ||
9c96033c | 5593 | case WHILE_STMT: |
2055d27a | 5594 | if (!RECUR (WHILE_COND (t), rval)) |
9c96033c | 5595 | return false; |
2055d27a | 5596 | if (!RECUR (WHILE_BODY (t), any)) |
9c96033c | 5597 | return false; |
5598 | return true; | |
5599 | ||
5600 | case SWITCH_STMT: | |
2055d27a | 5601 | if (!RECUR (SWITCH_STMT_COND (t), rval)) |
9c96033c | 5602 | return false; |
748c426a | 5603 | /* FIXME we don't check SWITCH_STMT_BODY currently, because even |
5604 | unreachable labels would be checked. */ | |
9c96033c | 5605 | return true; |
5606 | ||
da7981e0 | 5607 | case STMT_EXPR: |
2055d27a | 5608 | return RECUR (STMT_EXPR_STMT (t), rval); |
da7981e0 | 5609 | |
09b42213 | 5610 | case LAMBDA_EXPR: |
27db1f50 | 5611 | if (cxx_dialect >= cxx17) |
5612 | /* In C++17 lambdas can be constexpr, don't give up yet. */ | |
5613 | return true; | |
5614 | else if (flags & tf_error) | |
5615 | error_at (loc, "lambda-expression is not a constant expression " | |
5616 | "before C++17"); | |
5617 | return false; | |
5618 | ||
09b42213 | 5619 | case DYNAMIC_CAST_EXPR: |
5620 | case PSEUDO_DTOR_EXPR: | |
09b42213 | 5621 | case NEW_EXPR: |
5622 | case VEC_NEW_EXPR: | |
5623 | case DELETE_EXPR: | |
5624 | case VEC_DELETE_EXPR: | |
5625 | case THROW_EXPR: | |
d6a08f5c | 5626 | case OMP_PARALLEL: |
5627 | case OMP_TASK: | |
5628 | case OMP_FOR: | |
83728168 | 5629 | case OMP_SIMD: |
d6a08f5c | 5630 | case OMP_DISTRIBUTE: |
5631 | case OMP_TASKLOOP: | |
5632 | case OMP_TEAMS: | |
5633 | case OMP_TARGET_DATA: | |
5634 | case OMP_TARGET: | |
5635 | case OMP_SECTIONS: | |
5636 | case OMP_ORDERED: | |
5637 | case OMP_CRITICAL: | |
5638 | case OMP_SINGLE: | |
5639 | case OMP_SECTION: | |
5640 | case OMP_MASTER: | |
5641 | case OMP_TASKGROUP: | |
5642 | case OMP_TARGET_UPDATE: | |
5643 | case OMP_TARGET_ENTER_DATA: | |
5644 | case OMP_TARGET_EXIT_DATA: | |
09b42213 | 5645 | case OMP_ATOMIC: |
5646 | case OMP_ATOMIC_READ: | |
5647 | case OMP_ATOMIC_CAPTURE_OLD: | |
5648 | case OMP_ATOMIC_CAPTURE_NEW: | |
d6a08f5c | 5649 | case OACC_PARALLEL: |
5650 | case OACC_KERNELS: | |
5651 | case OACC_DATA: | |
5652 | case OACC_HOST_DATA: | |
5653 | case OACC_LOOP: | |
5654 | case OACC_CACHE: | |
5655 | case OACC_DECLARE: | |
5656 | case OACC_ENTER_DATA: | |
5657 | case OACC_EXIT_DATA: | |
5658 | case OACC_UPDATE: | |
09b42213 | 5659 | /* GCC internal stuff. */ |
5660 | case VA_ARG_EXPR: | |
5661 | case OBJ_TYPE_REF: | |
09b42213 | 5662 | case TRANSACTION_EXPR: |
9c96033c | 5663 | case ASM_EXPR: |
9abecca2 | 5664 | case AT_ENCODE_EXPR: |
9c96033c | 5665 | fail: |
09b42213 | 5666 | if (flags & tf_error) |
d6a08f5c | 5667 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 5668 | return false; |
5669 | ||
5670 | case TYPEID_EXPR: | |
5671 | /* -- a typeid expression whose operand is of polymorphic | |
5672 | class type; */ | |
5673 | { | |
5674 | tree e = TREE_OPERAND (t, 0); | |
5675 | if (!TYPE_P (e) && !type_dependent_expression_p (e) | |
5676 | && TYPE_POLYMORPHIC_P (TREE_TYPE (e))) | |
5677 | { | |
5678 | if (flags & tf_error) | |
d6a08f5c | 5679 | error_at (loc, "typeid-expression is not a constant expression " |
5680 | "because %qE is of polymorphic type", e); | |
09b42213 | 5681 | return false; |
5682 | } | |
5683 | return true; | |
5684 | } | |
5685 | ||
57e83b58 | 5686 | case POINTER_DIFF_EXPR: |
09b42213 | 5687 | case MINUS_EXPR: |
09b42213 | 5688 | want_rval = true; |
5689 | goto binary; | |
5690 | ||
5691 | case LT_EXPR: | |
5692 | case LE_EXPR: | |
5693 | case GT_EXPR: | |
5694 | case GE_EXPR: | |
5695 | case EQ_EXPR: | |
5696 | case NE_EXPR: | |
09b42213 | 5697 | want_rval = true; |
5698 | goto binary; | |
5699 | ||
9c96033c | 5700 | case PREINCREMENT_EXPR: |
5701 | case POSTINCREMENT_EXPR: | |
5702 | case PREDECREMENT_EXPR: | |
5703 | case POSTDECREMENT_EXPR: | |
5704 | if (cxx_dialect < cxx14) | |
5705 | goto fail; | |
5706 | goto unary; | |
5707 | ||
09b42213 | 5708 | case BIT_NOT_EXPR: |
5709 | /* A destructor. */ | |
5710 | if (TYPE_P (TREE_OPERAND (t, 0))) | |
5711 | return true; | |
e3533433 | 5712 | /* fall through. */ |
09b42213 | 5713 | |
09b42213 | 5714 | case CONJ_EXPR: |
5715 | case SAVE_EXPR: | |
5716 | case FIX_TRUNC_EXPR: | |
5717 | case FLOAT_EXPR: | |
5718 | case NEGATE_EXPR: | |
5719 | case ABS_EXPR: | |
5720 | case TRUTH_NOT_EXPR: | |
5721 | case FIXED_CONVERT_EXPR: | |
5722 | case UNARY_PLUS_EXPR: | |
6fdf70f5 | 5723 | case UNARY_LEFT_FOLD_EXPR: |
5724 | case UNARY_RIGHT_FOLD_EXPR: | |
9c96033c | 5725 | unary: |
2055d27a | 5726 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 5727 | |
5728 | case CAST_EXPR: | |
5729 | case CONST_CAST_EXPR: | |
5730 | case STATIC_CAST_EXPR: | |
5731 | case REINTERPRET_CAST_EXPR: | |
5732 | case IMPLICIT_CONV_EXPR: | |
5733 | if (cxx_dialect < cxx11 | |
5734 | && !dependent_type_p (TREE_TYPE (t)) | |
5735 | && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t))) | |
5736 | /* In C++98, a conversion to non-integral type can't be part of a | |
5737 | constant expression. */ | |
5738 | { | |
5739 | if (flags & tf_error) | |
d6a08f5c | 5740 | error_at (loc, |
5741 | "cast to non-integral type %qT in a constant expression", | |
5742 | TREE_TYPE (t)); | |
09b42213 | 5743 | return false; |
5744 | } | |
5745 | ||
2055d27a | 5746 | return (RECUR (TREE_OPERAND (t, 0), |
5747 | TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE)); | |
09b42213 | 5748 | |
9c96033c | 5749 | case BIND_EXPR: |
2055d27a | 5750 | return RECUR (BIND_EXPR_BODY (t), want_rval); |
9c96033c | 5751 | |
9c96033c | 5752 | case CLEANUP_POINT_EXPR: |
5753 | case MUST_NOT_THROW_EXPR: | |
5754 | case TRY_CATCH_EXPR: | |
7f67d68c | 5755 | case TRY_BLOCK: |
9c96033c | 5756 | case EH_SPEC_BLOCK: |
5757 | case EXPR_STMT: | |
09b42213 | 5758 | case PAREN_EXPR: |
5759 | case NON_DEPENDENT_EXPR: | |
5760 | /* For convenience. */ | |
5761 | case RETURN_EXPR: | |
d1980671 | 5762 | case LOOP_EXPR: |
5763 | case EXIT_EXPR: | |
2055d27a | 5764 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5765 | |
33603066 | 5766 | case DECL_EXPR: |
5767 | tmp = DECL_EXPR_DECL (t); | |
5768 | if (VAR_P (tmp) && !DECL_ARTIFICIAL (tmp)) | |
5769 | { | |
5770 | if (TREE_STATIC (tmp)) | |
5771 | { | |
5772 | if (flags & tf_error) | |
5773 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 5774 | "%<static%> in %<constexpr%> context", tmp); |
33603066 | 5775 | return false; |
5776 | } | |
5777 | else if (CP_DECL_THREAD_LOCAL_P (tmp)) | |
5778 | { | |
5779 | if (flags & tf_error) | |
5780 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 5781 | "%<thread_local%> in %<constexpr%> context", tmp); |
33603066 | 5782 | return false; |
5783 | } | |
282ea908 | 5784 | else if (!check_for_uninitialized_const_var |
5785 | (tmp, /*constexpr_context_p=*/true, flags)) | |
5786 | return false; | |
33603066 | 5787 | } |
5788 | return RECUR (tmp, want_rval); | |
5789 | ||
7f67d68c | 5790 | case TRY_FINALLY_EXPR: |
5791 | return (RECUR (TREE_OPERAND (t, 0), want_rval) | |
5792 | && RECUR (TREE_OPERAND (t, 1), any)); | |
5793 | ||
09b42213 | 5794 | case SCOPE_REF: |
2055d27a | 5795 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 5796 | |
5797 | case TARGET_EXPR: | |
07d8961c | 5798 | if (!TARGET_EXPR_DIRECT_INIT_P (t) |
5799 | && !literal_type_p (TREE_TYPE (t))) | |
09b42213 | 5800 | { |
5801 | if (flags & tf_error) | |
5802 | { | |
d6a08f5c | 5803 | error_at (loc, "temporary of non-literal type %qT in a " |
5804 | "constant expression", TREE_TYPE (t)); | |
09b42213 | 5805 | explain_non_literal_class (TREE_TYPE (t)); |
5806 | } | |
5807 | return false; | |
5808 | } | |
e3533433 | 5809 | /* FALLTHRU */ |
09b42213 | 5810 | case INIT_EXPR: |
2055d27a | 5811 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 5812 | |
5813 | case CONSTRUCTOR: | |
5814 | { | |
5815 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
5816 | constructor_elt *ce; | |
5817 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2055d27a | 5818 | if (!RECUR (ce->value, want_rval)) |
09b42213 | 5819 | return false; |
5820 | return true; | |
5821 | } | |
5822 | ||
5823 | case TREE_LIST: | |
5824 | { | |
5825 | gcc_assert (TREE_PURPOSE (t) == NULL_TREE | |
5826 | || DECL_P (TREE_PURPOSE (t))); | |
2055d27a | 5827 | if (!RECUR (TREE_VALUE (t), want_rval)) |
09b42213 | 5828 | return false; |
5829 | if (TREE_CHAIN (t) == NULL_TREE) | |
5830 | return true; | |
2055d27a | 5831 | return RECUR (TREE_CHAIN (t), want_rval); |
09b42213 | 5832 | } |
5833 | ||
5834 | case TRUNC_DIV_EXPR: | |
5835 | case CEIL_DIV_EXPR: | |
5836 | case FLOOR_DIV_EXPR: | |
5837 | case ROUND_DIV_EXPR: | |
5838 | case TRUNC_MOD_EXPR: | |
5839 | case CEIL_MOD_EXPR: | |
5840 | case ROUND_MOD_EXPR: | |
5841 | { | |
5842 | tree denom = TREE_OPERAND (t, 1); | |
2055d27a | 5843 | if (!RECUR (denom, rval)) |
09b42213 | 5844 | return false; |
5845 | /* We can't call cxx_eval_outermost_constant_expr on an expression | |
21131a05 | 5846 | that hasn't been through instantiate_non_dependent_expr yet. */ |
09b42213 | 5847 | if (!processing_template_decl) |
5848 | denom = cxx_eval_outermost_constant_expr (denom, true); | |
5849 | if (integer_zerop (denom)) | |
5850 | { | |
5851 | if (flags & tf_error) | |
ea034e2c | 5852 | error ("division by zero is not a constant expression"); |
09b42213 | 5853 | return false; |
5854 | } | |
5855 | else | |
5856 | { | |
5857 | want_rval = true; | |
2055d27a | 5858 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5859 | } |
5860 | } | |
5861 | ||
5862 | case COMPOUND_EXPR: | |
5863 | { | |
5864 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
5865 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
5866 | introduced by build_call_a. */ | |
5867 | tree op0 = TREE_OPERAND (t, 0); | |
5868 | tree op1 = TREE_OPERAND (t, 1); | |
5869 | STRIP_NOPS (op1); | |
5870 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
5871 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
2055d27a | 5872 | return RECUR (op0, want_rval); |
09b42213 | 5873 | else |
5874 | goto binary; | |
5875 | } | |
5876 | ||
5877 | /* If the first operand is the non-short-circuit constant, look at | |
5878 | the second operand; otherwise we only care about the first one for | |
5879 | potentiality. */ | |
5880 | case TRUTH_AND_EXPR: | |
5881 | case TRUTH_ANDIF_EXPR: | |
5882 | tmp = boolean_true_node; | |
5883 | goto truth; | |
5884 | case TRUTH_OR_EXPR: | |
5885 | case TRUTH_ORIF_EXPR: | |
5886 | tmp = boolean_false_node; | |
5887 | truth: | |
5888 | { | |
5889 | tree op = TREE_OPERAND (t, 0); | |
2055d27a | 5890 | if (!RECUR (op, rval)) |
09b42213 | 5891 | return false; |
5892 | if (!processing_template_decl) | |
5893 | op = cxx_eval_outermost_constant_expr (op, true); | |
5894 | if (tree_int_cst_equal (op, tmp)) | |
2055d27a | 5895 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 5896 | else |
5897 | return true; | |
5898 | } | |
5899 | ||
5900 | case PLUS_EXPR: | |
5901 | case MULT_EXPR: | |
5902 | case POINTER_PLUS_EXPR: | |
5903 | case RDIV_EXPR: | |
5904 | case EXACT_DIV_EXPR: | |
5905 | case MIN_EXPR: | |
5906 | case MAX_EXPR: | |
5907 | case LSHIFT_EXPR: | |
5908 | case RSHIFT_EXPR: | |
5909 | case LROTATE_EXPR: | |
5910 | case RROTATE_EXPR: | |
5911 | case BIT_IOR_EXPR: | |
5912 | case BIT_XOR_EXPR: | |
5913 | case BIT_AND_EXPR: | |
5914 | case TRUTH_XOR_EXPR: | |
5915 | case UNORDERED_EXPR: | |
5916 | case ORDERED_EXPR: | |
5917 | case UNLT_EXPR: | |
5918 | case UNLE_EXPR: | |
5919 | case UNGT_EXPR: | |
5920 | case UNGE_EXPR: | |
5921 | case UNEQ_EXPR: | |
5922 | case LTGT_EXPR: | |
5923 | case RANGE_EXPR: | |
5924 | case COMPLEX_EXPR: | |
5925 | want_rval = true; | |
5926 | /* Fall through. */ | |
5927 | case ARRAY_REF: | |
5928 | case ARRAY_RANGE_REF: | |
5929 | case MEMBER_REF: | |
5930 | case DOTSTAR_EXPR: | |
f0abe78f | 5931 | case MEM_REF: |
6fdf70f5 | 5932 | case BINARY_LEFT_FOLD_EXPR: |
5933 | case BINARY_RIGHT_FOLD_EXPR: | |
09b42213 | 5934 | binary: |
5935 | for (i = 0; i < 2; ++i) | |
2055d27a | 5936 | if (!RECUR (TREE_OPERAND (t, i), want_rval)) |
09b42213 | 5937 | return false; |
5938 | return true; | |
5939 | ||
09b42213 | 5940 | case FMA_EXPR: |
5941 | case VEC_PERM_EXPR: | |
5942 | for (i = 0; i < 3; ++i) | |
2055d27a | 5943 | if (!RECUR (TREE_OPERAND (t, i), true)) |
09b42213 | 5944 | return false; |
5945 | return true; | |
5946 | ||
5947 | case COND_EXPR: | |
b0fe8b95 | 5948 | if (COND_EXPR_IS_VEC_DELETE (t)) |
5949 | { | |
5950 | if (flags & tf_error) | |
d6a08f5c | 5951 | error_at (loc, "%<delete[]%> is not a constant expression"); |
b0fe8b95 | 5952 | return false; |
5953 | } | |
5954 | /* Fall through. */ | |
5955 | case IF_STMT: | |
09b42213 | 5956 | case VEC_COND_EXPR: |
5957 | /* If the condition is a known constant, we know which of the legs we | |
5958 | care about; otherwise we only require that the condition and | |
5959 | either of the legs be potentially constant. */ | |
5960 | tmp = TREE_OPERAND (t, 0); | |
2055d27a | 5961 | if (!RECUR (tmp, rval)) |
09b42213 | 5962 | return false; |
5963 | if (!processing_template_decl) | |
5964 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
5965 | if (integer_zerop (tmp)) | |
2055d27a | 5966 | return RECUR (TREE_OPERAND (t, 2), want_rval); |
09b42213 | 5967 | else if (TREE_CODE (tmp) == INTEGER_CST) |
2055d27a | 5968 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 5969 | for (i = 1; i < 3; ++i) |
5970 | if (potential_constant_expression_1 (TREE_OPERAND (t, i), | |
7e1f8be4 | 5971 | want_rval, strict, now, tf_none)) |
09b42213 | 5972 | return true; |
5973 | if (flags & tf_error) | |
d6a08f5c | 5974 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 5975 | return false; |
5976 | ||
5977 | case VEC_INIT_EXPR: | |
5978 | if (VEC_INIT_EXPR_IS_CONSTEXPR (t)) | |
5979 | return true; | |
5980 | if (flags & tf_error) | |
5981 | { | |
d6a08f5c | 5982 | error_at (loc, "non-constant array initialization"); |
09b42213 | 5983 | diagnose_non_constexpr_vec_init (t); |
5984 | } | |
5985 | return false; | |
5986 | ||
db1ae94f | 5987 | case TYPE_DECL: |
5988 | case TAG_DEFN: | |
5989 | /* We can see these in statement-expressions. */ | |
5990 | return true; | |
5991 | ||
fd130325 | 5992 | case CLEANUP_STMT: |
d2c63826 | 5993 | case EMPTY_CLASS_EXPR: |
38ef3642 | 5994 | case PREDICT_EXPR: |
d2c63826 | 5995 | return false; |
5996 | ||
d1980671 | 5997 | case GOTO_EXPR: |
5998 | { | |
5999 | tree *target = &TREE_OPERAND (t, 0); | |
d40a1eac | 6000 | /* Gotos representing break and continue are OK. */ |
6001 | if (breaks (target) || continues (target)) | |
6002 | return true; | |
6003 | if (flags & tf_error) | |
d6a08f5c | 6004 | error_at (loc, "%<goto%> is not a constant expression"); |
d40a1eac | 6005 | return false; |
d1980671 | 6006 | } |
6007 | ||
24c6ee98 | 6008 | case ANNOTATE_EXPR: |
24c6ee98 | 6009 | return RECUR (TREE_OPERAND (t, 0), rval); |
6010 | ||
09b42213 | 6011 | default: |
6012 | if (objc_is_property_ref (t)) | |
6013 | return false; | |
6014 | ||
6015 | sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t))); | |
d40a1eac | 6016 | gcc_unreachable (); |
09b42213 | 6017 | return false; |
6018 | } | |
2055d27a | 6019 | #undef RECUR |
09b42213 | 6020 | } |
6021 | ||
6022 | /* The main entry point to the above. */ | |
6023 | ||
6024 | bool | |
6025 | potential_constant_expression (tree t) | |
6026 | { | |
7e1f8be4 | 6027 | return potential_constant_expression_1 (t, false, true, false, tf_none); |
09b42213 | 6028 | } |
6029 | ||
6030 | /* As above, but require a constant rvalue. */ | |
6031 | ||
6032 | bool | |
6033 | potential_rvalue_constant_expression (tree t) | |
6034 | { | |
7e1f8be4 | 6035 | return potential_constant_expression_1 (t, true, true, false, tf_none); |
09b42213 | 6036 | } |
6037 | ||
6038 | /* Like above, but complain about non-constant expressions. */ | |
6039 | ||
6040 | bool | |
6041 | require_potential_constant_expression (tree t) | |
6042 | { | |
7e1f8be4 | 6043 | return potential_constant_expression_1 (t, false, true, false, tf_warning_or_error); |
09b42213 | 6044 | } |
6045 | ||
6046 | /* Cross product of the above. */ | |
6047 | ||
6048 | bool | |
6049 | require_potential_rvalue_constant_expression (tree t) | |
6050 | { | |
7e1f8be4 | 6051 | return potential_constant_expression_1 (t, true, true, false, tf_warning_or_error); |
6052 | } | |
6053 | ||
6054 | /* Like potential_constant_expression, but don't consider possible constexpr | |
6055 | substitution of the current function. That is, PARM_DECL qualifies under | |
6056 | potential_constant_expression, but not here. | |
6057 | ||
6058 | This is basically what you can check when any actual constant values might | |
6059 | be value-dependent. */ | |
6060 | ||
6061 | bool | |
6062 | is_constant_expression (tree t) | |
6063 | { | |
6064 | return potential_constant_expression_1 (t, false, true, true, tf_none); | |
6065 | } | |
6066 | ||
6067 | /* Like above, but complain about non-constant expressions. */ | |
6068 | ||
6069 | bool | |
6070 | require_constant_expression (tree t) | |
6071 | { | |
6072 | return potential_constant_expression_1 (t, false, true, true, | |
6073 | tf_warning_or_error); | |
6074 | } | |
6075 | ||
6076 | /* Like is_constant_expression, but allow const variables that are not allowed | |
6077 | under constexpr rules. */ | |
6078 | ||
6079 | bool | |
6080 | is_static_init_expression (tree t) | |
6081 | { | |
6082 | return potential_constant_expression_1 (t, false, false, true, tf_none); | |
09b42213 | 6083 | } |
6084 | ||
29cf24ec | 6085 | /* Returns true if T is a potential constant expression that is not |
6086 | instantiation-dependent, and therefore a candidate for constant folding even | |
6087 | in a template. */ | |
6088 | ||
6089 | bool | |
7e1f8be4 | 6090 | is_nondependent_constant_expression (tree t) |
29cf24ec | 6091 | { |
6092 | return (!type_unknown_p (t) | |
6093 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6094 | && is_constant_expression (t) |
29cf24ec | 6095 | && !instantiation_dependent_expression_p (t)); |
6096 | } | |
6097 | ||
6098 | /* Returns true if T is a potential static initializer expression that is not | |
6099 | instantiation-dependent. */ | |
6100 | ||
6101 | bool | |
7e1f8be4 | 6102 | is_nondependent_static_init_expression (tree t) |
29cf24ec | 6103 | { |
6104 | return (!type_unknown_p (t) | |
6105 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6106 | && is_static_init_expression (t) |
29cf24ec | 6107 | && !instantiation_dependent_expression_p (t)); |
6108 | } | |
6109 | ||
a050099a | 6110 | /* Finalize constexpr processing after parsing. */ |
6111 | ||
6112 | void | |
6113 | fini_constexpr (void) | |
6114 | { | |
6115 | /* The contexpr call and fundef copies tables are no longer needed. */ | |
6116 | constexpr_call_table = NULL; | |
6117 | fundef_copies_table = NULL; | |
6118 | } | |
6119 | ||
09b42213 | 6120 | #include "gt-cp-constexpr.h" |