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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) |
90ad495b | 63 | || TYPE_REF_P (t) |
dd418b39 | 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. */; | |
03dbe51b | 94 | else if (type_uses_auto (type)) |
95 | /* We don't know the actual type yet. */; | |
09b42213 | 96 | else if (!literal_type_p (type)) |
97 | { | |
98 | if (DECL_DECLARED_CONSTEXPR_P (decl)) | |
e45408ff | 99 | { |
bc35ef65 | 100 | auto_diagnostic_group d; |
5967b28b | 101 | error ("the type %qT of %<constexpr%> variable %qD " |
102 | "is not literal", type, decl); | |
e45408ff | 103 | explain_non_literal_class (type); |
e89257db | 104 | decl = error_mark_node; |
e45408ff | 105 | } |
09b42213 | 106 | else |
9c96033c | 107 | { |
b7e4a558 | 108 | if (!is_instantiation_of_constexpr (current_function_decl)) |
e45408ff | 109 | { |
bc35ef65 | 110 | auto_diagnostic_group d; |
e45408ff | 111 | error ("variable %qD of non-literal type %qT in %<constexpr%> " |
112 | "function", decl, type); | |
113 | explain_non_literal_class (type); | |
e89257db | 114 | decl = error_mark_node; |
e45408ff | 115 | } |
9c96033c | 116 | cp_function_chain->invalid_constexpr = true; |
117 | } | |
09b42213 | 118 | } |
fdafeeb7 | 119 | else if (DECL_DECLARED_CONSTEXPR_P (decl) |
120 | && variably_modified_type_p (type, NULL_TREE)) | |
121 | { | |
122 | error ("%<constexpr%> variable %qD has variably-modified type %qT", | |
123 | decl, type); | |
124 | decl = error_mark_node; | |
125 | } | |
09b42213 | 126 | } |
127 | return decl; | |
128 | } | |
129 | ||
130 | /* Representation of entries in the constexpr function definition table. */ | |
131 | ||
132 | struct GTY((for_user)) constexpr_fundef { | |
133 | tree decl; | |
134 | tree body; | |
135 | }; | |
136 | ||
b594087e | 137 | struct constexpr_fundef_hasher : ggc_ptr_hash<constexpr_fundef> |
09b42213 | 138 | { |
139 | static hashval_t hash (constexpr_fundef *); | |
140 | static bool equal (constexpr_fundef *, constexpr_fundef *); | |
141 | }; | |
142 | ||
143 | /* This table holds all constexpr function definitions seen in | |
144 | the current translation unit. */ | |
145 | ||
146 | static GTY (()) hash_table<constexpr_fundef_hasher> *constexpr_fundef_table; | |
147 | ||
148 | /* Utility function used for managing the constexpr function table. | |
149 | Return true if the entries pointed to by P and Q are for the | |
150 | same constexpr function. */ | |
151 | ||
152 | inline bool | |
153 | constexpr_fundef_hasher::equal (constexpr_fundef *lhs, constexpr_fundef *rhs) | |
154 | { | |
155 | return lhs->decl == rhs->decl; | |
156 | } | |
157 | ||
158 | /* Utility function used for managing the constexpr function table. | |
159 | Return a hash value for the entry pointed to by Q. */ | |
160 | ||
161 | inline hashval_t | |
162 | constexpr_fundef_hasher::hash (constexpr_fundef *fundef) | |
163 | { | |
164 | return DECL_UID (fundef->decl); | |
165 | } | |
166 | ||
167 | /* Return a previously saved definition of function FUN. */ | |
168 | ||
169 | static constexpr_fundef * | |
170 | retrieve_constexpr_fundef (tree fun) | |
171 | { | |
172 | constexpr_fundef fundef = { NULL, NULL }; | |
173 | if (constexpr_fundef_table == NULL) | |
174 | return NULL; | |
175 | ||
176 | fundef.decl = fun; | |
177 | return constexpr_fundef_table->find (&fundef); | |
178 | } | |
179 | ||
180 | /* Check whether the parameter and return types of FUN are valid for a | |
181 | constexpr function, and complain if COMPLAIN. */ | |
182 | ||
33603066 | 183 | bool |
09b42213 | 184 | is_valid_constexpr_fn (tree fun, bool complain) |
185 | { | |
186 | bool ret = true; | |
187 | ||
7896267d | 188 | if (DECL_INHERITED_CTOR (fun) |
09b42213 | 189 | && TREE_CODE (fun) == TEMPLATE_DECL) |
190 | { | |
191 | ret = false; | |
192 | if (complain) | |
5967b28b | 193 | error ("inherited constructor %qD is not %<constexpr%>", |
7896267d | 194 | DECL_INHERITED_CTOR (fun)); |
09b42213 | 195 | } |
196 | else | |
197 | { | |
198 | for (tree parm = FUNCTION_FIRST_USER_PARM (fun); | |
199 | parm != NULL_TREE; parm = TREE_CHAIN (parm)) | |
200 | if (!literal_type_p (TREE_TYPE (parm))) | |
201 | { | |
202 | ret = false; | |
203 | if (complain) | |
204 | { | |
bc35ef65 | 205 | auto_diagnostic_group d; |
5967b28b | 206 | error ("invalid type for parameter %d of %<constexpr%> " |
09b42213 | 207 | "function %q+#D", DECL_PARM_INDEX (parm), fun); |
208 | explain_non_literal_class (TREE_TYPE (parm)); | |
209 | } | |
210 | } | |
211 | } | |
212 | ||
672871ce | 213 | if (LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) && cxx_dialect < cxx17) |
214 | { | |
215 | ret = false; | |
216 | if (complain) | |
217 | inform (DECL_SOURCE_LOCATION (fun), | |
5967b28b | 218 | "lambdas are implicitly %<constexpr%> only in C++17 and later"); |
672871ce | 219 | } |
220 | else if (!DECL_CONSTRUCTOR_P (fun)) | |
09b42213 | 221 | { |
222 | tree rettype = TREE_TYPE (TREE_TYPE (fun)); | |
223 | if (!literal_type_p (rettype)) | |
224 | { | |
225 | ret = false; | |
226 | if (complain) | |
227 | { | |
bc35ef65 | 228 | auto_diagnostic_group d; |
5967b28b | 229 | error ("invalid return type %qT of %<constexpr%> function %q+D", |
09b42213 | 230 | rettype, fun); |
231 | explain_non_literal_class (rettype); | |
232 | } | |
233 | } | |
234 | ||
d66f34cf | 235 | /* C++14 DR 1684 removed this restriction. */ |
236 | if (cxx_dialect < cxx14 | |
237 | && DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
09b42213 | 238 | && !CLASSTYPE_LITERAL_P (DECL_CONTEXT (fun))) |
239 | { | |
240 | ret = false; | |
bc35ef65 | 241 | if (complain) |
242 | { | |
243 | auto_diagnostic_group d; | |
244 | if (pedwarn (DECL_SOURCE_LOCATION (fun), OPT_Wpedantic, | |
245 | "enclosing class of %<constexpr%> non-static" | |
246 | " member function %q+#D is not a literal type", | |
247 | fun)) | |
248 | explain_non_literal_class (DECL_CONTEXT (fun)); | |
249 | } | |
09b42213 | 250 | } |
251 | } | |
252 | else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun))) | |
253 | { | |
254 | ret = false; | |
255 | if (complain) | |
256 | error ("%q#T has virtual base classes", DECL_CONTEXT (fun)); | |
257 | } | |
258 | ||
259 | return ret; | |
260 | } | |
261 | ||
262 | /* Subroutine of build_data_member_initialization. MEMBER is a COMPONENT_REF | |
263 | for a member of an anonymous aggregate, INIT is the initializer for that | |
264 | member, and VEC_OUTER is the vector of constructor elements for the class | |
265 | whose constructor we are processing. Add the initializer to the vector | |
266 | and return true to indicate success. */ | |
267 | ||
268 | static bool | |
269 | build_anon_member_initialization (tree member, tree init, | |
270 | vec<constructor_elt, va_gc> **vec_outer) | |
271 | { | |
272 | /* MEMBER presents the relevant fields from the inside out, but we need | |
273 | to build up the initializer from the outside in so that we can reuse | |
274 | previously built CONSTRUCTORs if this is, say, the second field in an | |
275 | anonymous struct. So we use a vec as a stack. */ | |
276 | auto_vec<tree, 2> fields; | |
277 | do | |
278 | { | |
279 | fields.safe_push (TREE_OPERAND (member, 1)); | |
280 | member = TREE_OPERAND (member, 0); | |
281 | } | |
282 | while (ANON_AGGR_TYPE_P (TREE_TYPE (member)) | |
283 | && TREE_CODE (member) == COMPONENT_REF); | |
284 | ||
285 | /* VEC has the constructor elements vector for the context of FIELD. | |
286 | If FIELD is an anonymous aggregate, we will push inside it. */ | |
287 | vec<constructor_elt, va_gc> **vec = vec_outer; | |
288 | tree field; | |
289 | while (field = fields.pop(), | |
290 | ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
291 | { | |
292 | tree ctor; | |
293 | /* If there is already an outer constructor entry for the anonymous | |
294 | aggregate FIELD, use it; otherwise, insert one. */ | |
295 | if (vec_safe_is_empty (*vec) | |
296 | || (*vec)->last().index != field) | |
297 | { | |
298 | ctor = build_constructor (TREE_TYPE (field), NULL); | |
299 | CONSTRUCTOR_APPEND_ELT (*vec, field, ctor); | |
300 | } | |
301 | else | |
302 | ctor = (*vec)->last().value; | |
303 | vec = &CONSTRUCTOR_ELTS (ctor); | |
304 | } | |
305 | ||
306 | /* Now we're at the innermost field, the one that isn't an anonymous | |
307 | aggregate. Add its initializer to the CONSTRUCTOR and we're done. */ | |
308 | gcc_assert (fields.is_empty()); | |
309 | CONSTRUCTOR_APPEND_ELT (*vec, field, init); | |
310 | ||
311 | return true; | |
312 | } | |
313 | ||
314 | /* Subroutine of build_constexpr_constructor_member_initializers. | |
315 | The expression tree T represents a data member initialization | |
316 | in a (constexpr) constructor definition. Build a pairing of | |
317 | the data member with its initializer, and prepend that pair | |
318 | to the existing initialization pair INITS. */ | |
319 | ||
320 | static bool | |
321 | build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec) | |
322 | { | |
323 | tree member, init; | |
324 | if (TREE_CODE (t) == CLEANUP_POINT_EXPR) | |
325 | t = TREE_OPERAND (t, 0); | |
326 | if (TREE_CODE (t) == EXPR_STMT) | |
327 | t = TREE_OPERAND (t, 0); | |
328 | if (t == error_mark_node) | |
329 | return false; | |
330 | if (TREE_CODE (t) == STATEMENT_LIST) | |
331 | { | |
332 | tree_stmt_iterator i; | |
333 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
334 | { | |
335 | if (! build_data_member_initialization (tsi_stmt (i), vec)) | |
336 | return false; | |
337 | } | |
338 | return true; | |
339 | } | |
340 | if (TREE_CODE (t) == CLEANUP_STMT) | |
341 | { | |
342 | /* We can't see a CLEANUP_STMT in a constructor for a literal class, | |
343 | but we can in a constexpr constructor for a non-literal class. Just | |
344 | ignore it; either all the initialization will be constant, in which | |
345 | case the cleanup can't run, or it can't be constexpr. | |
346 | Still recurse into CLEANUP_BODY. */ | |
347 | return build_data_member_initialization (CLEANUP_BODY (t), vec); | |
348 | } | |
349 | if (TREE_CODE (t) == CONVERT_EXPR) | |
350 | t = TREE_OPERAND (t, 0); | |
351 | if (TREE_CODE (t) == INIT_EXPR | |
9c96033c | 352 | /* vptr initialization shows up as a MODIFY_EXPR. In C++14 we only |
353 | use what this function builds for cx_check_missing_mem_inits, and | |
354 | assignment in the ctor body doesn't count. */ | |
355 | || (cxx_dialect < cxx14 && TREE_CODE (t) == MODIFY_EXPR)) | |
09b42213 | 356 | { |
357 | member = TREE_OPERAND (t, 0); | |
358 | init = break_out_target_exprs (TREE_OPERAND (t, 1)); | |
359 | } | |
360 | else if (TREE_CODE (t) == CALL_EXPR) | |
361 | { | |
9c96033c | 362 | tree fn = get_callee_fndecl (t); |
363 | if (!fn || !DECL_CONSTRUCTOR_P (fn)) | |
364 | /* We're only interested in calls to subobject constructors. */ | |
365 | return true; | |
09b42213 | 366 | member = CALL_EXPR_ARG (t, 0); |
367 | /* We don't use build_cplus_new here because it complains about | |
368 | abstract bases. Leaving the call unwrapped means that it has the | |
369 | wrong type, but cxx_eval_constant_expression doesn't care. */ | |
370 | init = break_out_target_exprs (t); | |
371 | } | |
372 | else if (TREE_CODE (t) == BIND_EXPR) | |
373 | return build_data_member_initialization (BIND_EXPR_BODY (t), vec); | |
09b42213 | 374 | else |
9c96033c | 375 | /* Don't add anything else to the CONSTRUCTOR. */ |
376 | return true; | |
09b42213 | 377 | if (INDIRECT_REF_P (member)) |
378 | member = TREE_OPERAND (member, 0); | |
379 | if (TREE_CODE (member) == NOP_EXPR) | |
380 | { | |
381 | tree op = member; | |
382 | STRIP_NOPS (op); | |
383 | if (TREE_CODE (op) == ADDR_EXPR) | |
384 | { | |
385 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
386 | (TREE_TYPE (TREE_TYPE (op)), | |
387 | TREE_TYPE (TREE_TYPE (member)))); | |
388 | /* Initializing a cv-qualified member; we need to look through | |
389 | the const_cast. */ | |
390 | member = op; | |
391 | } | |
392 | else if (op == current_class_ptr | |
393 | && (same_type_ignoring_top_level_qualifiers_p | |
394 | (TREE_TYPE (TREE_TYPE (member)), | |
395 | current_class_type))) | |
396 | /* Delegating constructor. */ | |
397 | member = op; | |
398 | else | |
399 | { | |
400 | /* This is an initializer for an empty base; keep it for now so | |
401 | we can check it in cxx_eval_bare_aggregate. */ | |
402 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (member)))); | |
403 | } | |
404 | } | |
405 | if (TREE_CODE (member) == ADDR_EXPR) | |
406 | member = TREE_OPERAND (member, 0); | |
407 | if (TREE_CODE (member) == COMPONENT_REF) | |
408 | { | |
409 | tree aggr = TREE_OPERAND (member, 0); | |
4952bc85 | 410 | if (TREE_CODE (aggr) == VAR_DECL) |
411 | /* Initializing a local variable, don't add anything. */ | |
412 | return true; | |
09b42213 | 413 | if (TREE_CODE (aggr) != COMPONENT_REF) |
414 | /* Normal member initialization. */ | |
415 | member = TREE_OPERAND (member, 1); | |
416 | else if (ANON_AGGR_TYPE_P (TREE_TYPE (aggr))) | |
417 | /* Initializing a member of an anonymous union. */ | |
418 | return build_anon_member_initialization (member, init, vec); | |
419 | else | |
420 | /* We're initializing a vtable pointer in a base. Leave it as | |
421 | COMPONENT_REF so we remember the path to get to the vfield. */ | |
422 | gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node); | |
423 | } | |
424 | ||
c678e23e | 425 | /* Value-initialization can produce multiple initializers for the |
426 | same field; use the last one. */ | |
427 | if (!vec_safe_is_empty (*vec) && (*vec)->last().index == member) | |
428 | (*vec)->last().value = init; | |
429 | else | |
430 | CONSTRUCTOR_APPEND_ELT (*vec, member, init); | |
09b42213 | 431 | return true; |
432 | } | |
433 | ||
434 | /* Subroutine of check_constexpr_ctor_body_1 and constexpr_fn_retval. | |
435 | In C++11 mode checks that the TYPE_DECLs in the BIND_EXPR_VARS of a | |
436 | BIND_EXPR conform to 7.1.5/3/4 on typedef and alias declarations. */ | |
437 | ||
438 | static bool | |
439 | check_constexpr_bind_expr_vars (tree t) | |
440 | { | |
441 | gcc_assert (TREE_CODE (t) == BIND_EXPR); | |
442 | ||
09b42213 | 443 | for (tree var = BIND_EXPR_VARS (t); var; var = DECL_CHAIN (var)) |
444 | if (TREE_CODE (var) == TYPE_DECL | |
04103c39 | 445 | && DECL_IMPLICIT_TYPEDEF_P (var) |
446 | && !LAMBDA_TYPE_P (TREE_TYPE (var))) | |
09b42213 | 447 | return false; |
448 | return true; | |
449 | } | |
450 | ||
451 | /* Subroutine of check_constexpr_ctor_body. */ | |
452 | ||
453 | static bool | |
454 | check_constexpr_ctor_body_1 (tree last, tree list) | |
455 | { | |
456 | switch (TREE_CODE (list)) | |
457 | { | |
458 | case DECL_EXPR: | |
810702a2 | 459 | if (TREE_CODE (DECL_EXPR_DECL (list)) == USING_DECL |
460 | || TREE_CODE (DECL_EXPR_DECL (list)) == TYPE_DECL) | |
09b42213 | 461 | return true; |
09b42213 | 462 | return false; |
463 | ||
464 | case CLEANUP_POINT_EXPR: | |
465 | return check_constexpr_ctor_body (last, TREE_OPERAND (list, 0), | |
466 | /*complain=*/false); | |
467 | ||
468 | case BIND_EXPR: | |
469 | if (!check_constexpr_bind_expr_vars (list) | |
470 | || !check_constexpr_ctor_body (last, BIND_EXPR_BODY (list), | |
471 | /*complain=*/false)) | |
472 | return false; | |
473 | return true; | |
474 | ||
475 | case USING_STMT: | |
476 | case STATIC_ASSERT: | |
90567983 | 477 | case DEBUG_BEGIN_STMT: |
09b42213 | 478 | return true; |
479 | ||
480 | default: | |
481 | return false; | |
482 | } | |
483 | } | |
484 | ||
485 | /* Make sure that there are no statements after LAST in the constructor | |
486 | body represented by LIST. */ | |
487 | ||
488 | bool | |
489 | check_constexpr_ctor_body (tree last, tree list, bool complain) | |
490 | { | |
9c96033c | 491 | /* C++14 doesn't require a constexpr ctor to have an empty body. */ |
492 | if (cxx_dialect >= cxx14) | |
493 | return true; | |
494 | ||
09b42213 | 495 | bool ok = true; |
496 | if (TREE_CODE (list) == STATEMENT_LIST) | |
497 | { | |
498 | tree_stmt_iterator i = tsi_last (list); | |
499 | for (; !tsi_end_p (i); tsi_prev (&i)) | |
500 | { | |
501 | tree t = tsi_stmt (i); | |
502 | if (t == last) | |
503 | break; | |
504 | if (!check_constexpr_ctor_body_1 (last, t)) | |
505 | { | |
506 | ok = false; | |
507 | break; | |
508 | } | |
509 | } | |
510 | } | |
511 | else if (list != last | |
512 | && !check_constexpr_ctor_body_1 (last, list)) | |
513 | ok = false; | |
514 | if (!ok) | |
515 | { | |
516 | if (complain) | |
5967b28b | 517 | error ("%<constexpr%> constructor does not have empty body"); |
09b42213 | 518 | DECL_DECLARED_CONSTEXPR_P (current_function_decl) = false; |
519 | } | |
520 | return ok; | |
521 | } | |
522 | ||
523 | /* V is a vector of constructor elements built up for the base and member | |
524 | initializers of a constructor for TYPE. They need to be in increasing | |
525 | offset order, which they might not be yet if TYPE has a primary base | |
526 | which is not first in the base-clause or a vptr and at least one base | |
527 | all of which are non-primary. */ | |
528 | ||
529 | static vec<constructor_elt, va_gc> * | |
530 | sort_constexpr_mem_initializers (tree type, vec<constructor_elt, va_gc> *v) | |
531 | { | |
532 | tree pri = CLASSTYPE_PRIMARY_BINFO (type); | |
533 | tree field_type; | |
534 | unsigned i; | |
535 | constructor_elt *ce; | |
536 | ||
537 | if (pri) | |
538 | field_type = BINFO_TYPE (pri); | |
539 | else if (TYPE_CONTAINS_VPTR_P (type)) | |
540 | field_type = vtbl_ptr_type_node; | |
541 | else | |
542 | return v; | |
543 | ||
544 | /* Find the element for the primary base or vptr and move it to the | |
545 | beginning of the vec. */ | |
546 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
547 | if (TREE_TYPE (ce->index) == field_type) | |
548 | break; | |
549 | ||
550 | if (i > 0 && i < vec_safe_length (v)) | |
551 | { | |
552 | vec<constructor_elt, va_gc> &vref = *v; | |
553 | constructor_elt elt = vref[i]; | |
554 | for (; i > 0; --i) | |
555 | vref[i] = vref[i-1]; | |
556 | vref[0] = elt; | |
557 | } | |
558 | ||
559 | return v; | |
560 | } | |
561 | ||
562 | /* Build compile-time evalable representations of member-initializer list | |
563 | for a constexpr constructor. */ | |
564 | ||
565 | static tree | |
566 | build_constexpr_constructor_member_initializers (tree type, tree body) | |
567 | { | |
568 | vec<constructor_elt, va_gc> *vec = NULL; | |
569 | bool ok = true; | |
816919e1 | 570 | while (true) |
571 | switch (TREE_CODE (body)) | |
572 | { | |
573 | case MUST_NOT_THROW_EXPR: | |
574 | case EH_SPEC_BLOCK: | |
575 | body = TREE_OPERAND (body, 0); | |
576 | break; | |
577 | ||
578 | case STATEMENT_LIST: | |
579 | for (tree_stmt_iterator i = tsi_start (body); | |
580 | !tsi_end_p (i); tsi_next (&i)) | |
581 | { | |
582 | body = tsi_stmt (i); | |
583 | if (TREE_CODE (body) == BIND_EXPR) | |
584 | break; | |
585 | } | |
586 | break; | |
587 | ||
588 | case BIND_EXPR: | |
589 | body = BIND_EXPR_BODY (body); | |
590 | goto found; | |
591 | ||
592 | default: | |
593 | gcc_unreachable (); | |
8a36d0ec | 594 | } |
816919e1 | 595 | found: |
09b42213 | 596 | if (TREE_CODE (body) == CLEANUP_POINT_EXPR) |
597 | { | |
598 | body = TREE_OPERAND (body, 0); | |
599 | if (TREE_CODE (body) == EXPR_STMT) | |
600 | body = TREE_OPERAND (body, 0); | |
601 | if (TREE_CODE (body) == INIT_EXPR | |
602 | && (same_type_ignoring_top_level_qualifiers_p | |
603 | (TREE_TYPE (TREE_OPERAND (body, 0)), | |
604 | current_class_type))) | |
605 | { | |
606 | /* Trivial copy. */ | |
607 | return TREE_OPERAND (body, 1); | |
608 | } | |
609 | ok = build_data_member_initialization (body, &vec); | |
610 | } | |
611 | else if (TREE_CODE (body) == STATEMENT_LIST) | |
612 | { | |
613 | tree_stmt_iterator i; | |
614 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
615 | { | |
616 | ok = build_data_member_initialization (tsi_stmt (i), &vec); | |
617 | if (!ok) | |
618 | break; | |
619 | } | |
620 | } | |
621 | else if (TREE_CODE (body) == TRY_BLOCK) | |
622 | { | |
623 | error ("body of %<constexpr%> constructor cannot be " | |
624 | "a function-try-block"); | |
625 | return error_mark_node; | |
626 | } | |
627 | else if (EXPR_P (body)) | |
628 | ok = build_data_member_initialization (body, &vec); | |
629 | else | |
630 | gcc_assert (errorcount > 0); | |
631 | if (ok) | |
632 | { | |
633 | if (vec_safe_length (vec) > 0) | |
634 | { | |
635 | /* In a delegating constructor, return the target. */ | |
636 | constructor_elt *ce = &(*vec)[0]; | |
637 | if (ce->index == current_class_ptr) | |
638 | { | |
639 | body = ce->value; | |
640 | vec_free (vec); | |
641 | return body; | |
642 | } | |
643 | } | |
644 | vec = sort_constexpr_mem_initializers (type, vec); | |
645 | return build_constructor (type, vec); | |
646 | } | |
647 | else | |
648 | return error_mark_node; | |
649 | } | |
650 | ||
2fb20ba2 | 651 | /* We have an expression tree T that represents a call, either CALL_EXPR |
652 | or AGGR_INIT_EXPR. If the call is lexically to a named function, | |
653 | retrun the _DECL for that function. */ | |
654 | ||
655 | static tree | |
656 | get_function_named_in_call (tree t) | |
657 | { | |
658 | tree fun = cp_get_callee (t); | |
659 | if (fun && TREE_CODE (fun) == ADDR_EXPR | |
660 | && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL) | |
661 | fun = TREE_OPERAND (fun, 0); | |
662 | return fun; | |
663 | } | |
664 | ||
09b42213 | 665 | /* Subroutine of register_constexpr_fundef. BODY is the body of a function |
666 | declared to be constexpr, or a sub-statement thereof. Returns the | |
667 | return value if suitable, error_mark_node for a statement not allowed in | |
668 | a constexpr function, or NULL_TREE if no return value was found. */ | |
669 | ||
c49bd35e | 670 | tree |
09b42213 | 671 | constexpr_fn_retval (tree body) |
672 | { | |
673 | switch (TREE_CODE (body)) | |
674 | { | |
675 | case STATEMENT_LIST: | |
676 | { | |
677 | tree_stmt_iterator i; | |
678 | tree expr = NULL_TREE; | |
679 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
680 | { | |
681 | tree s = constexpr_fn_retval (tsi_stmt (i)); | |
682 | if (s == error_mark_node) | |
683 | return error_mark_node; | |
684 | else if (s == NULL_TREE) | |
685 | /* Keep iterating. */; | |
686 | else if (expr) | |
687 | /* Multiple return statements. */ | |
688 | return error_mark_node; | |
689 | else | |
690 | expr = s; | |
691 | } | |
692 | return expr; | |
693 | } | |
694 | ||
695 | case RETURN_EXPR: | |
696 | return break_out_target_exprs (TREE_OPERAND (body, 0)); | |
697 | ||
698 | case DECL_EXPR: | |
394aed6a | 699 | { |
700 | tree decl = DECL_EXPR_DECL (body); | |
701 | if (TREE_CODE (decl) == USING_DECL | |
702 | /* Accept __func__, __FUNCTION__, and __PRETTY_FUNCTION__. */ | |
703 | || DECL_ARTIFICIAL (decl)) | |
704 | return NULL_TREE; | |
705 | return error_mark_node; | |
706 | } | |
09b42213 | 707 | |
708 | case CLEANUP_POINT_EXPR: | |
709 | return constexpr_fn_retval (TREE_OPERAND (body, 0)); | |
710 | ||
711 | case BIND_EXPR: | |
712 | if (!check_constexpr_bind_expr_vars (body)) | |
713 | return error_mark_node; | |
714 | return constexpr_fn_retval (BIND_EXPR_BODY (body)); | |
715 | ||
716 | case USING_STMT: | |
90567983 | 717 | case DEBUG_BEGIN_STMT: |
09b42213 | 718 | return NULL_TREE; |
719 | ||
2fb20ba2 | 720 | case CALL_EXPR: |
721 | { | |
722 | tree fun = get_function_named_in_call (body); | |
723 | if (fun != NULL_TREE | |
18d371d3 | 724 | && DECL_BUILT_IN_CLASS (fun) == BUILT_IN_NORMAL |
2fb20ba2 | 725 | && DECL_FUNCTION_CODE (fun) == BUILT_IN_UNREACHABLE) |
726 | return NULL_TREE; | |
727 | } | |
728 | /* Fallthru. */ | |
729 | ||
09b42213 | 730 | default: |
731 | return error_mark_node; | |
732 | } | |
733 | } | |
734 | ||
735 | /* Subroutine of register_constexpr_fundef. BODY is the DECL_SAVED_TREE of | |
736 | FUN; do the necessary transformations to turn it into a single expression | |
737 | that we can store in the hash table. */ | |
738 | ||
739 | static tree | |
740 | massage_constexpr_body (tree fun, tree body) | |
741 | { | |
742 | if (DECL_CONSTRUCTOR_P (fun)) | |
743 | body = build_constexpr_constructor_member_initializers | |
744 | (DECL_CONTEXT (fun), body); | |
9c96033c | 745 | else if (cxx_dialect < cxx14) |
09b42213 | 746 | { |
747 | if (TREE_CODE (body) == EH_SPEC_BLOCK) | |
748 | body = EH_SPEC_STMTS (body); | |
749 | if (TREE_CODE (body) == MUST_NOT_THROW_EXPR) | |
750 | body = TREE_OPERAND (body, 0); | |
751 | body = constexpr_fn_retval (body); | |
752 | } | |
753 | return body; | |
754 | } | |
755 | ||
2f4cab3c | 756 | /* CTYPE is a type constructed from BODY. Return true if some |
757 | bases/fields are uninitialized, and complain if COMPLAIN. */ | |
09b42213 | 758 | |
759 | static bool | |
2f4cab3c | 760 | cx_check_missing_mem_inits (tree ctype, tree body, bool complain) |
09b42213 | 761 | { |
2f4cab3c | 762 | unsigned nelts = 0; |
763 | ||
764 | if (body) | |
765 | { | |
766 | if (TREE_CODE (body) != CONSTRUCTOR) | |
767 | return false; | |
768 | nelts = CONSTRUCTOR_NELTS (body); | |
769 | } | |
770 | tree field = TYPE_FIELDS (ctype); | |
09b42213 | 771 | |
772 | if (TREE_CODE (ctype) == UNION_TYPE) | |
773 | { | |
774 | if (nelts == 0 && next_initializable_field (field)) | |
775 | { | |
776 | if (complain) | |
777 | error ("%<constexpr%> constructor for union %qT must " | |
778 | "initialize exactly one non-static data member", ctype); | |
779 | return true; | |
780 | } | |
781 | return false; | |
782 | } | |
783 | ||
2f4cab3c | 784 | /* Iterate over the CONSTRUCTOR, checking any missing fields don't |
785 | need an explicit initialization. */ | |
786 | bool bad = false; | |
787 | for (unsigned i = 0; i <= nelts; ++i) | |
09b42213 | 788 | { |
2f4cab3c | 789 | tree index = NULL_TREE; |
790 | if (i < nelts) | |
09b42213 | 791 | { |
792 | index = CONSTRUCTOR_ELT (body, i)->index; | |
793 | /* Skip base and vtable inits. */ | |
794 | if (TREE_CODE (index) != FIELD_DECL | |
795 | || DECL_ARTIFICIAL (index)) | |
796 | continue; | |
797 | } | |
2f4cab3c | 798 | |
09b42213 | 799 | for (; field != index; field = DECL_CHAIN (field)) |
800 | { | |
801 | tree ftype; | |
2f4cab3c | 802 | if (TREE_CODE (field) != FIELD_DECL) |
803 | continue; | |
3cde3c29 | 804 | if (DECL_UNNAMED_BIT_FIELD (field)) |
09b42213 | 805 | continue; |
2f4cab3c | 806 | if (DECL_ARTIFICIAL (field)) |
807 | continue; | |
808 | if (ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
809 | { | |
810 | /* Recurse to check the anonummous aggregate member. */ | |
811 | bad |= cx_check_missing_mem_inits | |
812 | (TREE_TYPE (field), NULL_TREE, complain); | |
813 | if (bad && !complain) | |
814 | return true; | |
815 | continue; | |
816 | } | |
09b42213 | 817 | ftype = strip_array_types (TREE_TYPE (field)); |
818 | if (type_has_constexpr_default_constructor (ftype)) | |
819 | { | |
820 | /* It's OK to skip a member with a trivial constexpr ctor. | |
821 | A constexpr ctor that isn't trivial should have been | |
822 | added in by now. */ | |
823 | gcc_checking_assert (!TYPE_HAS_COMPLEX_DFLT (ftype) | |
824 | || errorcount != 0); | |
825 | continue; | |
826 | } | |
827 | if (!complain) | |
828 | return true; | |
bc35ef65 | 829 | auto_diagnostic_group d; |
859e2c29 | 830 | error ("member %qD must be initialized by mem-initializer " |
831 | "in %<constexpr%> constructor", field); | |
832 | inform (DECL_SOURCE_LOCATION (field), "declared here"); | |
09b42213 | 833 | bad = true; |
834 | } | |
835 | if (field == NULL_TREE) | |
836 | break; | |
2f4cab3c | 837 | |
838 | if (ANON_AGGR_TYPE_P (TREE_TYPE (index))) | |
839 | { | |
840 | /* Check the anonymous aggregate initializer is valid. */ | |
841 | bad |= cx_check_missing_mem_inits | |
842 | (TREE_TYPE (index), CONSTRUCTOR_ELT (body, i)->value, complain); | |
843 | if (bad && !complain) | |
844 | return true; | |
845 | } | |
09b42213 | 846 | field = DECL_CHAIN (field); |
847 | } | |
848 | ||
849 | return bad; | |
850 | } | |
851 | ||
852 | /* We are processing the definition of the constexpr function FUN. | |
853 | Check that its BODY fulfills the propriate requirements and | |
854 | enter it in the constexpr function definition table. | |
855 | For constructor BODY is actually the TREE_LIST of the | |
856 | member-initializer list. */ | |
857 | ||
858 | tree | |
859 | register_constexpr_fundef (tree fun, tree body) | |
860 | { | |
861 | constexpr_fundef entry; | |
862 | constexpr_fundef **slot; | |
863 | ||
864 | if (!is_valid_constexpr_fn (fun, !DECL_GENERATED_P (fun))) | |
865 | return NULL; | |
866 | ||
6a385150 | 867 | tree massaged = massage_constexpr_body (fun, body); |
868 | if (massaged == NULL_TREE || massaged == error_mark_node) | |
09b42213 | 869 | { |
870 | if (!DECL_CONSTRUCTOR_P (fun)) | |
5967b28b | 871 | error ("body of %<constexpr%> function %qD not a return-statement", |
872 | fun); | |
09b42213 | 873 | return NULL; |
874 | } | |
875 | ||
6a385150 | 876 | if (!potential_rvalue_constant_expression (massaged)) |
09b42213 | 877 | { |
878 | if (!DECL_GENERATED_P (fun)) | |
6a385150 | 879 | require_potential_rvalue_constant_expression (massaged); |
09b42213 | 880 | return NULL; |
881 | } | |
882 | ||
883 | if (DECL_CONSTRUCTOR_P (fun) | |
2f4cab3c | 884 | && cx_check_missing_mem_inits (DECL_CONTEXT (fun), |
885 | massaged, !DECL_GENERATED_P (fun))) | |
09b42213 | 886 | return NULL; |
887 | ||
888 | /* Create the constexpr function table if necessary. */ | |
889 | if (constexpr_fundef_table == NULL) | |
890 | constexpr_fundef_table | |
891 | = hash_table<constexpr_fundef_hasher>::create_ggc (101); | |
892 | ||
893 | entry.decl = fun; | |
894 | entry.body = body; | |
895 | slot = constexpr_fundef_table->find_slot (&entry, INSERT); | |
896 | ||
897 | gcc_assert (*slot == NULL); | |
898 | *slot = ggc_alloc<constexpr_fundef> (); | |
899 | **slot = entry; | |
900 | ||
901 | return fun; | |
902 | } | |
903 | ||
904 | /* FUN is a non-constexpr function called in a context that requires a | |
905 | constant expression. If it comes from a constexpr template, explain why | |
906 | the instantiation isn't constexpr. */ | |
907 | ||
908 | void | |
909 | explain_invalid_constexpr_fn (tree fun) | |
910 | { | |
911 | static hash_set<tree> *diagnosed; | |
912 | tree body; | |
913 | location_t save_loc; | |
33603066 | 914 | /* Only diagnose defaulted functions, lambdas, or instantiations. */ |
09b42213 | 915 | if (!DECL_DEFAULTED_FN (fun) |
33603066 | 916 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) |
09b42213 | 917 | && !is_instantiation_of_constexpr (fun)) |
918 | return; | |
919 | if (diagnosed == NULL) | |
920 | diagnosed = new hash_set<tree>; | |
921 | if (diagnosed->add (fun)) | |
922 | /* Already explained. */ | |
923 | return; | |
924 | ||
925 | save_loc = input_location; | |
33603066 | 926 | if (!lambda_static_thunk_p (fun)) |
927 | { | |
928 | /* Diagnostics should completely ignore the static thunk, so leave | |
929 | input_location set to our caller's location. */ | |
930 | input_location = DECL_SOURCE_LOCATION (fun); | |
931 | inform (input_location, | |
5967b28b | 932 | "%qD is not usable as a %<constexpr%> function because:", fun); |
33603066 | 933 | } |
09b42213 | 934 | /* First check the declaration. */ |
935 | if (is_valid_constexpr_fn (fun, true)) | |
936 | { | |
937 | /* Then if it's OK, the body. */ | |
33603066 | 938 | if (!DECL_DECLARED_CONSTEXPR_P (fun) |
939 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun))) | |
09b42213 | 940 | explain_implicit_non_constexpr (fun); |
941 | else | |
942 | { | |
943 | body = massage_constexpr_body (fun, DECL_SAVED_TREE (fun)); | |
944 | require_potential_rvalue_constant_expression (body); | |
945 | if (DECL_CONSTRUCTOR_P (fun)) | |
2f4cab3c | 946 | cx_check_missing_mem_inits (DECL_CONTEXT (fun), body, true); |
09b42213 | 947 | } |
948 | } | |
949 | input_location = save_loc; | |
950 | } | |
951 | ||
952 | /* Objects of this type represent calls to constexpr functions | |
953 | along with the bindings of parameters to their arguments, for | |
954 | the purpose of compile time evaluation. */ | |
955 | ||
956 | struct GTY((for_user)) constexpr_call { | |
957 | /* Description of the constexpr function definition. */ | |
958 | constexpr_fundef *fundef; | |
959 | /* Parameter bindings environment. A TREE_LIST where each TREE_PURPOSE | |
960 | is a parameter _DECL and the TREE_VALUE is the value of the parameter. | |
961 | Note: This arrangement is made to accommodate the use of | |
962 | iterative_hash_template_arg (see pt.c). If you change this | |
963 | representation, also change the hash calculation in | |
964 | cxx_eval_call_expression. */ | |
965 | tree bindings; | |
966 | /* Result of the call. | |
967 | NULL means the call is being evaluated. | |
968 | error_mark_node means that the evaluation was erroneous; | |
969 | otherwise, the actuall value of the call. */ | |
970 | tree result; | |
971 | /* The hash of this call; we remember it here to avoid having to | |
972 | recalculate it when expanding the hash table. */ | |
973 | hashval_t hash; | |
974 | }; | |
975 | ||
b594087e | 976 | struct constexpr_call_hasher : ggc_ptr_hash<constexpr_call> |
09b42213 | 977 | { |
978 | static hashval_t hash (constexpr_call *); | |
979 | static bool equal (constexpr_call *, constexpr_call *); | |
cf72f34d | 980 | }; |
981 | ||
2a2770c6 | 982 | enum constexpr_switch_state { |
983 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
984 | and default: label for that switch has not been seen yet. */ | |
985 | css_default_not_seen, | |
986 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
987 | and default: label for that switch has been seen already. */ | |
988 | css_default_seen, | |
989 | /* Used when processing a switch for the second time by | |
990 | cxx_eval_switch_expr, where default: label should match. */ | |
991 | css_default_processing | |
992 | }; | |
993 | ||
cf72f34d | 994 | /* The constexpr expansion context. CALL is the current function |
995 | expansion, CTOR is the current aggregate initializer, OBJECT is the | |
996 | object being initialized by CTOR, either a VAR_DECL or a _REF. VALUES | |
997 | is a map of values of variables initialized within the expression. */ | |
998 | ||
999 | struct constexpr_ctx { | |
f9885b8a | 1000 | /* The innermost call we're evaluating. */ |
cf72f34d | 1001 | constexpr_call *call; |
f9885b8a | 1002 | /* Values for any temporaries or local variables within the |
1003 | constant-expression. */ | |
cf72f34d | 1004 | hash_map<tree,tree> *values; |
2631cb67 | 1005 | /* SAVE_EXPRs that we've seen within the current LOOP_EXPR. NULL if we |
1006 | aren't inside a loop. */ | |
1007 | hash_set<tree> *save_exprs; | |
f9885b8a | 1008 | /* The CONSTRUCTOR we're currently building up for an aggregate |
1009 | initializer. */ | |
cf72f34d | 1010 | tree ctor; |
f9885b8a | 1011 | /* The object we're building the CONSTRUCTOR for. */ |
cf72f34d | 1012 | tree object; |
2a2770c6 | 1013 | /* If inside SWITCH_EXPR. */ |
1014 | constexpr_switch_state *css_state; | |
f9885b8a | 1015 | /* Whether we should error on a non-constant expression or fail quietly. */ |
f83e6885 | 1016 | bool quiet; |
f9885b8a | 1017 | /* Whether we are strictly conforming to constant expression rules or |
1018 | trying harder to get a constant value. */ | |
2055d27a | 1019 | bool strict; |
18d371d3 | 1020 | /* Whether __builtin_is_constant_evaluated () should be true. */ |
1021 | bool pretend_const_required; | |
cf72f34d | 1022 | }; |
09b42213 | 1023 | |
1024 | /* A table of all constexpr calls that have been evaluated by the | |
1025 | compiler in this translation unit. */ | |
1026 | ||
a050099a | 1027 | static GTY (()) hash_table<constexpr_call_hasher> *constexpr_call_table; |
09b42213 | 1028 | |
cf72f34d | 1029 | static tree cxx_eval_constant_expression (const constexpr_ctx *, tree, |
b2a43197 | 1030 | bool, bool *, bool *, tree * = NULL); |
09b42213 | 1031 | |
1032 | /* Compute a hash value for a constexpr call representation. */ | |
1033 | ||
1034 | inline hashval_t | |
1035 | constexpr_call_hasher::hash (constexpr_call *info) | |
1036 | { | |
1037 | return info->hash; | |
1038 | } | |
1039 | ||
1040 | /* Return true if the objects pointed to by P and Q represent calls | |
1041 | to the same constexpr function with the same arguments. | |
1042 | Otherwise, return false. */ | |
1043 | ||
1044 | bool | |
1045 | constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs) | |
1046 | { | |
1047 | tree lhs_bindings; | |
1048 | tree rhs_bindings; | |
1049 | if (lhs == rhs) | |
c751e2cd | 1050 | return true; |
1051 | if (lhs->hash != rhs->hash) | |
1052 | return false; | |
09b42213 | 1053 | if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef)) |
c751e2cd | 1054 | return false; |
09b42213 | 1055 | lhs_bindings = lhs->bindings; |
1056 | rhs_bindings = rhs->bindings; | |
1057 | while (lhs_bindings != NULL && rhs_bindings != NULL) | |
1058 | { | |
1059 | tree lhs_arg = TREE_VALUE (lhs_bindings); | |
1060 | tree rhs_arg = TREE_VALUE (rhs_bindings); | |
1061 | gcc_assert (TREE_TYPE (lhs_arg) == TREE_TYPE (rhs_arg)); | |
1062 | if (!cp_tree_equal (lhs_arg, rhs_arg)) | |
c751e2cd | 1063 | return false; |
09b42213 | 1064 | lhs_bindings = TREE_CHAIN (lhs_bindings); |
1065 | rhs_bindings = TREE_CHAIN (rhs_bindings); | |
1066 | } | |
1067 | return lhs_bindings == rhs_bindings; | |
1068 | } | |
1069 | ||
1070 | /* Initialize the constexpr call table, if needed. */ | |
1071 | ||
1072 | static void | |
1073 | maybe_initialize_constexpr_call_table (void) | |
1074 | { | |
1075 | if (constexpr_call_table == NULL) | |
1076 | constexpr_call_table = hash_table<constexpr_call_hasher>::create_ggc (101); | |
1077 | } | |
1078 | ||
4f7ebe46 | 1079 | /* During constexpr CALL_EXPR evaluation, to avoid issues with sharing when |
1080 | a function happens to get called recursively, we unshare the callee | |
1081 | function's body and evaluate this unshared copy instead of evaluating the | |
1082 | original body. | |
1083 | ||
1084 | FUNDEF_COPIES_TABLE is a per-function freelist of these unshared function | |
1085 | copies. The underlying data structure of FUNDEF_COPIES_TABLE is a hash_map | |
a050099a | 1086 | that's keyed off of the original FUNCTION_DECL and whose value is a |
1087 | TREE_LIST of this function's unused copies awaiting reuse. | |
4f7ebe46 | 1088 | |
a050099a | 1089 | This is not GC-deletable to avoid GC affecting UID generation. */ |
4f7ebe46 | 1090 | |
a050099a | 1091 | static GTY(()) hash_map<tree, tree> *fundef_copies_table; |
4f7ebe46 | 1092 | |
1093 | /* Initialize FUNDEF_COPIES_TABLE if it's not initialized. */ | |
1094 | ||
1095 | static void | |
1096 | maybe_initialize_fundef_copies_table () | |
1097 | { | |
a050099a | 1098 | if (fundef_copies_table == NULL) |
1099 | fundef_copies_table = hash_map<tree,tree>::create_ggc (101); | |
4f7ebe46 | 1100 | } |
1101 | ||
1102 | /* Reuse a copy or create a new unshared copy of the function FUN. | |
886d5463 | 1103 | Return this copy. We use a TREE_LIST whose PURPOSE is body, VALUE |
1104 | is parms, TYPE is result. */ | |
4f7ebe46 | 1105 | |
a050099a | 1106 | static tree |
4f7ebe46 | 1107 | get_fundef_copy (tree fun) |
1108 | { | |
1109 | maybe_initialize_fundef_copies_table (); | |
1110 | ||
a050099a | 1111 | tree copy; |
886d5463 | 1112 | bool existed; |
1113 | tree *slot = &fundef_copies_table->get_or_insert (fun, &existed); | |
1114 | ||
1115 | if (!existed) | |
4f7ebe46 | 1116 | { |
886d5463 | 1117 | /* There is no cached function available, or in use. We can use |
1118 | the function directly. That the slot is now created records | |
1119 | that this function is now in use. */ | |
1120 | copy = build_tree_list (DECL_SAVED_TREE (fun), DECL_ARGUMENTS (fun)); | |
1121 | TREE_TYPE (copy) = DECL_RESULT (fun); | |
1122 | } | |
1123 | else if (*slot == NULL_TREE) | |
1124 | { | |
1125 | /* We've already used the function itself, so make a copy. */ | |
a050099a | 1126 | copy = build_tree_list (NULL, NULL); |
a050099a | 1127 | TREE_PURPOSE (copy) = copy_fn (fun, TREE_VALUE (copy), TREE_TYPE (copy)); |
4f7ebe46 | 1128 | } |
1129 | else | |
1130 | { | |
886d5463 | 1131 | /* We have a cached function available. */ |
4f7ebe46 | 1132 | copy = *slot; |
a050099a | 1133 | *slot = TREE_CHAIN (copy); |
4f7ebe46 | 1134 | } |
1135 | ||
1136 | return copy; | |
1137 | } | |
1138 | ||
886d5463 | 1139 | /* Save the copy COPY of function FUN for later reuse by |
1140 | get_fundef_copy(). By construction, there will always be an entry | |
1141 | to find. */ | |
4f7ebe46 | 1142 | |
1143 | static void | |
a050099a | 1144 | save_fundef_copy (tree fun, tree copy) |
4f7ebe46 | 1145 | { |
886d5463 | 1146 | tree *slot = fundef_copies_table->get (fun); |
a050099a | 1147 | TREE_CHAIN (copy) = *slot; |
4f7ebe46 | 1148 | *slot = copy; |
1149 | } | |
1150 | ||
09b42213 | 1151 | /* We have an expression tree T that represents a call, either CALL_EXPR |
1152 | or AGGR_INIT_EXPR. Return the Nth argument. */ | |
1153 | ||
1154 | static inline tree | |
1155 | get_nth_callarg (tree t, int n) | |
1156 | { | |
1157 | switch (TREE_CODE (t)) | |
1158 | { | |
1159 | case CALL_EXPR: | |
1160 | return CALL_EXPR_ARG (t, n); | |
1161 | ||
1162 | case AGGR_INIT_EXPR: | |
1163 | return AGGR_INIT_EXPR_ARG (t, n); | |
1164 | ||
1165 | default: | |
1166 | gcc_unreachable (); | |
1167 | return NULL; | |
1168 | } | |
1169 | } | |
1170 | ||
09b42213 | 1171 | /* Attempt to evaluate T which represents a call to a builtin function. |
1172 | We assume here that all builtin functions evaluate to scalar types | |
1173 | represented by _CST nodes. */ | |
1174 | ||
1175 | static tree | |
f1c6af10 | 1176 | cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, |
1227ba74 | 1177 | bool lval, |
09b42213 | 1178 | bool *non_constant_p, bool *overflow_p) |
1179 | { | |
1180 | const int nargs = call_expr_nargs (t); | |
1181 | tree *args = (tree *) alloca (nargs * sizeof (tree)); | |
1182 | tree new_call; | |
1183 | int i; | |
f1c6af10 | 1184 | |
1185 | /* Don't fold __builtin_constant_p within a constexpr function. */ | |
18d371d3 | 1186 | bool bi_const_p = DECL_IS_BUILTIN_CONSTANT_P (fun); |
efe6a40a | 1187 | |
0f5cec54 | 1188 | /* If we aren't requiring a constant expression, defer __builtin_constant_p |
1189 | in a constexpr function until we have values for the parameters. */ | |
efe6a40a | 1190 | if (bi_const_p |
0f5cec54 | 1191 | && ctx->quiet |
f1c6af10 | 1192 | && current_function_decl |
1193 | && DECL_DECLARED_CONSTEXPR_P (current_function_decl)) | |
09b42213 | 1194 | { |
f1c6af10 | 1195 | *non_constant_p = true; |
1196 | return t; | |
09b42213 | 1197 | } |
f1c6af10 | 1198 | |
18d371d3 | 1199 | /* For __builtin_is_constant_evaluated, defer it if not |
1200 | ctx->pretend_const_required, otherwise fold it to true. */ | |
1201 | if (DECL_BUILT_IN_CLASS (fun) == BUILT_IN_FRONTEND | |
1202 | && (int) DECL_FUNCTION_CODE (fun) == CP_BUILT_IN_IS_CONSTANT_EVALUATED) | |
1203 | { | |
1204 | if (!ctx->pretend_const_required) | |
1205 | { | |
1206 | *non_constant_p = true; | |
1207 | return t; | |
1208 | } | |
1209 | return boolean_true_node; | |
1210 | } | |
1211 | ||
f1c6af10 | 1212 | /* Be permissive for arguments to built-ins; __builtin_constant_p should |
1213 | return constant false for a non-constant argument. */ | |
1214 | constexpr_ctx new_ctx = *ctx; | |
1215 | new_ctx.quiet = true; | |
1216 | bool dummy1 = false, dummy2 = false; | |
1217 | for (i = 0; i < nargs; ++i) | |
efe6a40a | 1218 | { |
91b66c3c | 1219 | args[i] = CALL_EXPR_ARG (t, i); |
1220 | /* If builtin_valid_in_constant_expr_p is true, | |
1221 | potential_constant_expression_1 has not recursed into the arguments | |
1222 | of the builtin, verify it here. */ | |
1223 | if (!builtin_valid_in_constant_expr_p (fun) | |
1224 | || potential_constant_expression (args[i])) | |
1225 | args[i] = cxx_eval_constant_expression (&new_ctx, args[i], false, | |
1226 | &dummy1, &dummy2); | |
efe6a40a | 1227 | if (bi_const_p) |
1228 | /* For __built_in_constant_p, fold all expressions with constant values | |
1229 | even if they aren't C++ constant-expressions. */ | |
1230 | args[i] = cp_fully_fold (args[i]); | |
1231 | } | |
f1c6af10 | 1232 | |
1233 | bool save_ffbcp = force_folding_builtin_constant_p; | |
1234 | force_folding_builtin_constant_p = true; | |
051eb924 | 1235 | new_call = fold_builtin_call_array (EXPR_LOCATION (t), TREE_TYPE (t), |
1236 | CALL_EXPR_FN (t), nargs, args); | |
f1c6af10 | 1237 | force_folding_builtin_constant_p = save_ffbcp; |
051eb924 | 1238 | if (new_call == NULL) |
1239 | { | |
1240 | if (!*non_constant_p && !ctx->quiet) | |
1241 | { | |
2fb20ba2 | 1242 | /* Do not allow__builtin_unreachable in constexpr function. |
1243 | The __builtin_unreachable call with BUILTINS_LOCATION | |
1244 | comes from cp_maybe_instrument_return. */ | |
18d371d3 | 1245 | if (DECL_BUILT_IN_CLASS (fun) == BUILT_IN_NORMAL |
1246 | && DECL_FUNCTION_CODE (fun) == BUILT_IN_UNREACHABLE | |
2fb20ba2 | 1247 | && EXPR_LOCATION (t) == BUILTINS_LOCATION) |
5967b28b | 1248 | error ("%<constexpr%> call flows off the end of the function"); |
2fb20ba2 | 1249 | else |
1250 | { | |
1251 | new_call = build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t), | |
1252 | CALL_EXPR_FN (t), nargs, args); | |
1253 | error ("%q+E is not a constant expression", new_call); | |
1254 | } | |
051eb924 | 1255 | } |
1256 | *non_constant_p = true; | |
1257 | return t; | |
1258 | } | |
1259 | ||
7e1f8be4 | 1260 | if (!is_constant_expression (new_call)) |
051eb924 | 1261 | { |
1262 | if (!*non_constant_p && !ctx->quiet) | |
1263 | error ("%q+E is not a constant expression", new_call); | |
1264 | *non_constant_p = true; | |
1265 | return t; | |
1266 | } | |
1267 | ||
1268 | return cxx_eval_constant_expression (&new_ctx, new_call, lval, | |
1269 | non_constant_p, overflow_p); | |
09b42213 | 1270 | } |
1271 | ||
1272 | /* TEMP is the constant value of a temporary object of type TYPE. Adjust | |
1273 | the type of the value to match. */ | |
1274 | ||
1275 | static tree | |
1276 | adjust_temp_type (tree type, tree temp) | |
1277 | { | |
1278 | if (TREE_TYPE (temp) == type) | |
1279 | return temp; | |
1280 | /* Avoid wrapping an aggregate value in a NOP_EXPR. */ | |
1281 | if (TREE_CODE (temp) == CONSTRUCTOR) | |
1282 | return build_constructor (type, CONSTRUCTOR_ELTS (temp)); | |
1283 | gcc_assert (scalarish_type_p (type)); | |
1284 | return cp_fold_convert (type, temp); | |
1285 | } | |
1286 | ||
e283bb4f | 1287 | /* Callback for walk_tree used by unshare_constructor. */ |
1288 | ||
1289 | static tree | |
1290 | find_constructor (tree *tp, int *walk_subtrees, void *) | |
1291 | { | |
1292 | if (TYPE_P (*tp)) | |
1293 | *walk_subtrees = 0; | |
1294 | if (TREE_CODE (*tp) == CONSTRUCTOR) | |
1295 | return *tp; | |
1296 | return NULL_TREE; | |
1297 | } | |
1298 | ||
1299 | /* If T is a CONSTRUCTOR or an expression that has a CONSTRUCTOR node as a | |
1300 | subexpression, return an unshared copy of T. Otherwise return T. */ | |
1301 | ||
1302 | static tree | |
1303 | unshare_constructor (tree t) | |
1304 | { | |
1305 | tree ctor = walk_tree (&t, find_constructor, NULL, NULL); | |
1306 | if (ctor != NULL_TREE) | |
1307 | return unshare_expr (t); | |
1308 | return t; | |
1309 | } | |
1310 | ||
09b42213 | 1311 | /* Subroutine of cxx_eval_call_expression. |
1312 | We are processing a call expression (either CALL_EXPR or | |
cf72f34d | 1313 | AGGR_INIT_EXPR) in the context of CTX. Evaluate |
09b42213 | 1314 | all arguments and bind their values to correspondings |
1315 | parameters, making up the NEW_CALL context. */ | |
1316 | ||
1317 | static void | |
cf72f34d | 1318 | cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, |
09b42213 | 1319 | constexpr_call *new_call, |
c8f6aeb1 | 1320 | bool *non_constant_p, bool *overflow_p, |
1321 | bool *non_constant_args) | |
09b42213 | 1322 | { |
1323 | const int nargs = call_expr_nargs (t); | |
1324 | tree fun = new_call->fundef->decl; | |
1325 | tree parms = DECL_ARGUMENTS (fun); | |
1326 | int i; | |
9c96033c | 1327 | tree *p = &new_call->bindings; |
09b42213 | 1328 | for (i = 0; i < nargs; ++i) |
1329 | { | |
1330 | tree x, arg; | |
1331 | tree type = parms ? TREE_TYPE (parms) : void_type_node; | |
09b42213 | 1332 | x = get_nth_callarg (t, i); |
cf72f34d | 1333 | /* For member function, the first argument is a pointer to the implied |
1334 | object. For a constructor, it might still be a dummy object, in | |
9c96033c | 1335 | which case we get the real argument from ctx. */ |
cf72f34d | 1336 | if (i == 0 && DECL_CONSTRUCTOR_P (fun) |
1337 | && is_dummy_object (x)) | |
1338 | { | |
1339 | x = ctx->object; | |
c017458d | 1340 | x = build_address (x); |
cf72f34d | 1341 | } |
2e1c71c2 | 1342 | arg = cxx_eval_constant_expression (ctx, x, /*lval=*/false, |
b2a43197 | 1343 | non_constant_p, overflow_p); |
09b42213 | 1344 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 1345 | if (*non_constant_p && ctx->quiet) |
09b42213 | 1346 | return; |
1347 | /* Just discard ellipsis args after checking their constantitude. */ | |
1348 | if (!parms) | |
1349 | continue; | |
2ba934c7 | 1350 | |
1351 | if (!*non_constant_p) | |
1352 | { | |
24d5b4f0 | 1353 | /* Don't share a CONSTRUCTOR that might be changed. */ |
1354 | arg = unshare_constructor (arg); | |
2ba934c7 | 1355 | /* Make sure the binding has the same type as the parm. But |
1356 | only for constant args. */ | |
90ad495b | 1357 | if (!TYPE_REF_P (type)) |
2ba934c7 | 1358 | arg = adjust_temp_type (type, arg); |
1359 | if (!TREE_CONSTANT (arg)) | |
1360 | *non_constant_args = true; | |
1361 | *p = build_tree_list (parms, arg); | |
1362 | p = &TREE_CHAIN (*p); | |
1363 | } | |
09b42213 | 1364 | parms = TREE_CHAIN (parms); |
1365 | } | |
1366 | } | |
1367 | ||
1368 | /* Variables and functions to manage constexpr call expansion context. | |
1369 | These do not need to be marked for PCH or GC. */ | |
1370 | ||
1371 | /* FIXME remember and print actual constant arguments. */ | |
16fb756f | 1372 | static vec<tree> call_stack; |
09b42213 | 1373 | static int call_stack_tick; |
1374 | static int last_cx_error_tick; | |
1375 | ||
1376 | static bool | |
1377 | push_cx_call_context (tree call) | |
1378 | { | |
1379 | ++call_stack_tick; | |
1380 | if (!EXPR_HAS_LOCATION (call)) | |
1381 | SET_EXPR_LOCATION (call, input_location); | |
1382 | call_stack.safe_push (call); | |
1383 | if (call_stack.length () > (unsigned) max_constexpr_depth) | |
1384 | return false; | |
1385 | return true; | |
1386 | } | |
1387 | ||
1388 | static void | |
1389 | pop_cx_call_context (void) | |
1390 | { | |
1391 | ++call_stack_tick; | |
1392 | call_stack.pop (); | |
1393 | } | |
1394 | ||
1395 | vec<tree> | |
1396 | cx_error_context (void) | |
1397 | { | |
1398 | vec<tree> r = vNULL; | |
1399 | if (call_stack_tick != last_cx_error_tick | |
1400 | && !call_stack.is_empty ()) | |
1401 | r = call_stack; | |
1402 | last_cx_error_tick = call_stack_tick; | |
1403 | return r; | |
1404 | } | |
1405 | ||
732905bb | 1406 | /* Evaluate a call T to a GCC internal function when possible and return |
1407 | the evaluated result or, under the control of CTX, give an error, set | |
1408 | NON_CONSTANT_P, and return the unevaluated call T otherwise. */ | |
1409 | ||
1410 | static tree | |
1411 | cxx_eval_internal_function (const constexpr_ctx *ctx, tree t, | |
1412 | bool lval, | |
1413 | bool *non_constant_p, bool *overflow_p) | |
1414 | { | |
1415 | enum tree_code opcode = ERROR_MARK; | |
1416 | ||
1417 | switch (CALL_EXPR_IFN (t)) | |
1418 | { | |
1419 | case IFN_UBSAN_NULL: | |
1420 | case IFN_UBSAN_BOUNDS: | |
1421 | case IFN_UBSAN_VPTR: | |
3c77f69c | 1422 | case IFN_FALLTHROUGH: |
732905bb | 1423 | return void_node; |
1424 | ||
1425 | case IFN_ADD_OVERFLOW: | |
1426 | opcode = PLUS_EXPR; | |
1427 | break; | |
1428 | case IFN_SUB_OVERFLOW: | |
1429 | opcode = MINUS_EXPR; | |
1430 | break; | |
1431 | case IFN_MUL_OVERFLOW: | |
1432 | opcode = MULT_EXPR; | |
1433 | break; | |
1434 | ||
6e1b2ffb | 1435 | case IFN_LAUNDER: |
1436 | return cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), | |
1437 | false, non_constant_p, overflow_p); | |
1438 | ||
732905bb | 1439 | default: |
1440 | if (!ctx->quiet) | |
d3a3cfb8 | 1441 | error_at (cp_expr_loc_or_loc (t, input_location), |
732905bb | 1442 | "call to internal function %qE", t); |
1443 | *non_constant_p = true; | |
1444 | return t; | |
1445 | } | |
1446 | ||
1447 | /* Evaluate constant arguments using OPCODE and return a complex | |
1448 | number containing the result and the overflow bit. */ | |
1449 | tree arg0 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), lval, | |
1450 | non_constant_p, overflow_p); | |
1451 | tree arg1 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 1), lval, | |
1452 | non_constant_p, overflow_p); | |
1453 | ||
1454 | if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) | |
1455 | { | |
d3a3cfb8 | 1456 | location_t loc = cp_expr_loc_or_loc (t, input_location); |
732905bb | 1457 | tree type = TREE_TYPE (TREE_TYPE (t)); |
1458 | tree result = fold_binary_loc (loc, opcode, type, | |
1459 | fold_convert_loc (loc, type, arg0), | |
1460 | fold_convert_loc (loc, type, arg1)); | |
1461 | tree ovf | |
1462 | = build_int_cst (type, arith_overflowed_p (opcode, type, arg0, arg1)); | |
1463 | /* Reset TREE_OVERFLOW to avoid warnings for the overflow. */ | |
1464 | if (TREE_OVERFLOW (result)) | |
1465 | TREE_OVERFLOW (result) = 0; | |
1466 | ||
1467 | return build_complex (TREE_TYPE (t), result, ovf); | |
1468 | } | |
1469 | ||
1470 | *non_constant_p = true; | |
1471 | return t; | |
1472 | } | |
1473 | ||
165d0d5b | 1474 | /* Clean CONSTRUCTOR_NO_CLEARING from CTOR and its sub-aggregates. */ |
79cdb4f5 | 1475 | |
1476 | static void | |
1477 | clear_no_implicit_zero (tree ctor) | |
1478 | { | |
165d0d5b | 1479 | if (CONSTRUCTOR_NO_CLEARING (ctor)) |
79cdb4f5 | 1480 | { |
165d0d5b | 1481 | CONSTRUCTOR_NO_CLEARING (ctor) = false; |
79cdb4f5 | 1482 | tree elt; unsigned HOST_WIDE_INT idx; |
1483 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (ctor), idx, elt) | |
1484 | if (TREE_CODE (elt) == CONSTRUCTOR) | |
1485 | clear_no_implicit_zero (elt); | |
1486 | } | |
1487 | } | |
1488 | ||
09b42213 | 1489 | /* Subroutine of cxx_eval_constant_expression. |
1490 | Evaluate the call expression tree T in the context of OLD_CALL expression | |
1491 | evaluation. */ | |
1492 | ||
1493 | static tree | |
cf72f34d | 1494 | cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1495 | bool lval, |
09b42213 | 1496 | bool *non_constant_p, bool *overflow_p) |
1497 | { | |
d3a3cfb8 | 1498 | location_t loc = cp_expr_loc_or_loc (t, input_location); |
09b42213 | 1499 | tree fun = get_function_named_in_call (t); |
09b42213 | 1500 | constexpr_call new_call = { NULL, NULL, NULL, 0 }; |
09b42213 | 1501 | bool depth_ok; |
1502 | ||
6b71bdb4 | 1503 | if (fun == NULL_TREE) |
732905bb | 1504 | return cxx_eval_internal_function (ctx, t, lval, |
1505 | non_constant_p, overflow_p); | |
6b71bdb4 | 1506 | |
09b42213 | 1507 | if (TREE_CODE (fun) != FUNCTION_DECL) |
1508 | { | |
1509 | /* Might be a constexpr function pointer. */ | |
f83e6885 | 1510 | fun = cxx_eval_constant_expression (ctx, fun, |
1227ba74 | 1511 | /*lval*/false, non_constant_p, |
b2a43197 | 1512 | overflow_p); |
09b42213 | 1513 | STRIP_NOPS (fun); |
1514 | if (TREE_CODE (fun) == ADDR_EXPR) | |
1515 | fun = TREE_OPERAND (fun, 0); | |
1516 | } | |
1517 | if (TREE_CODE (fun) != FUNCTION_DECL) | |
1518 | { | |
f83e6885 | 1519 | if (!ctx->quiet && !*non_constant_p) |
5967b28b | 1520 | error_at (loc, "expression %qE does not designate a %<constexpr%> " |
09b42213 | 1521 | "function", fun); |
1522 | *non_constant_p = true; | |
1523 | return t; | |
1524 | } | |
1525 | if (DECL_CLONED_FUNCTION_P (fun)) | |
1526 | fun = DECL_CLONED_FUNCTION (fun); | |
6b71bdb4 | 1527 | |
1528 | if (is_ubsan_builtin_p (fun)) | |
1529 | return void_node; | |
1530 | ||
09b42213 | 1531 | if (is_builtin_fn (fun)) |
f1c6af10 | 1532 | return cxx_eval_builtin_function_call (ctx, t, fun, |
1227ba74 | 1533 | lval, non_constant_p, overflow_p); |
09b42213 | 1534 | if (!DECL_DECLARED_CONSTEXPR_P (fun)) |
1535 | { | |
f83e6885 | 1536 | if (!ctx->quiet) |
09b42213 | 1537 | { |
1dcd84cf | 1538 | if (!lambda_static_thunk_p (fun)) |
5967b28b | 1539 | error_at (loc, "call to non-%<constexpr%> function %qD", fun); |
09b42213 | 1540 | explain_invalid_constexpr_fn (fun); |
1541 | } | |
1542 | *non_constant_p = true; | |
1543 | return t; | |
1544 | } | |
1545 | ||
9ebe2ea3 | 1546 | constexpr_ctx new_ctx = *ctx; |
1547 | if (DECL_CONSTRUCTOR_P (fun) && !ctx->object | |
1548 | && TREE_CODE (t) == AGGR_INIT_EXPR) | |
1549 | { | |
1550 | /* We want to have an initialization target for an AGGR_INIT_EXPR. | |
1551 | If we don't already have one in CTX, use the AGGR_INIT_EXPR_SLOT. */ | |
1552 | new_ctx.object = AGGR_INIT_EXPR_SLOT (t); | |
1553 | tree ctor = new_ctx.ctor = build_constructor (DECL_CONTEXT (fun), NULL); | |
165d0d5b | 1554 | CONSTRUCTOR_NO_CLEARING (ctor) = true; |
9ebe2ea3 | 1555 | ctx->values->put (new_ctx.object, ctor); |
1556 | ctx = &new_ctx; | |
1557 | } | |
1558 | ||
09b42213 | 1559 | /* Shortcut trivial constructor/op=. */ |
1560 | if (trivial_fn_p (fun)) | |
1561 | { | |
9ebe2ea3 | 1562 | tree init = NULL_TREE; |
09b42213 | 1563 | if (call_expr_nargs (t) == 2) |
9ebe2ea3 | 1564 | init = convert_from_reference (get_nth_callarg (t, 1)); |
09b42213 | 1565 | else if (TREE_CODE (t) == AGGR_INIT_EXPR |
1566 | && AGGR_INIT_ZERO_FIRST (t)) | |
9ebe2ea3 | 1567 | init = build_zero_init (DECL_CONTEXT (fun), NULL_TREE, false); |
1568 | if (init) | |
1569 | { | |
1570 | tree op = get_nth_callarg (t, 0); | |
1571 | if (is_dummy_object (op)) | |
1572 | op = ctx->object; | |
1573 | else | |
1574 | op = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (op)), op); | |
1575 | tree set = build2 (MODIFY_EXPR, TREE_TYPE (op), op, init); | |
0ce12360 | 1576 | new_ctx.call = &new_call; |
1577 | return cxx_eval_constant_expression (&new_ctx, set, lval, | |
9ebe2ea3 | 1578 | non_constant_p, overflow_p); |
1579 | } | |
09b42213 | 1580 | } |
1581 | ||
8afcf831 | 1582 | /* We can't defer instantiating the function any longer. */ |
1583 | if (!DECL_INITIAL (fun) | |
1584 | && DECL_TEMPLOID_INSTANTIATION (fun)) | |
1585 | { | |
31db86df | 1586 | location_t save_loc = input_location; |
1587 | input_location = loc; | |
8afcf831 | 1588 | ++function_depth; |
1589 | instantiate_decl (fun, /*defer_ok*/false, /*expl_inst*/false); | |
1590 | --function_depth; | |
31db86df | 1591 | input_location = save_loc; |
8afcf831 | 1592 | } |
1593 | ||
09b42213 | 1594 | /* If in direct recursive call, optimize definition search. */ |
0ce12360 | 1595 | if (ctx && ctx->call && ctx->call->fundef && ctx->call->fundef->decl == fun) |
cf72f34d | 1596 | new_call.fundef = ctx->call->fundef; |
09b42213 | 1597 | else |
1598 | { | |
1599 | new_call.fundef = retrieve_constexpr_fundef (fun); | |
d2a9b1c1 | 1600 | if (new_call.fundef == NULL || new_call.fundef->body == NULL |
1601 | || fun == current_function_decl) | |
09b42213 | 1602 | { |
f83e6885 | 1603 | if (!ctx->quiet) |
09b42213 | 1604 | { |
d2a9b1c1 | 1605 | /* We need to check for current_function_decl here in case we're |
1606 | being called during cp_fold_function, because at that point | |
1607 | DECL_INITIAL is set properly and we have a fundef but we | |
1608 | haven't lowered invisirefs yet (c++/70344). */ | |
1609 | if (DECL_INITIAL (fun) == error_mark_node | |
1610 | || fun == current_function_decl) | |
a0efa758 | 1611 | error_at (loc, "%qD called in a constant expression before its " |
1612 | "definition is complete", fun); | |
1613 | else if (DECL_INITIAL (fun)) | |
09b42213 | 1614 | { |
33603066 | 1615 | /* The definition of fun was somehow unsuitable. But pretend |
1616 | that lambda static thunks don't exist. */ | |
1617 | if (!lambda_static_thunk_p (fun)) | |
1618 | error_at (loc, "%qD called in a constant expression", fun); | |
09b42213 | 1619 | explain_invalid_constexpr_fn (fun); |
1620 | } | |
1621 | else | |
1622 | error_at (loc, "%qD used before its definition", fun); | |
1623 | } | |
1624 | *non_constant_p = true; | |
1625 | return t; | |
1626 | } | |
1627 | } | |
9c96033c | 1628 | |
c8f6aeb1 | 1629 | bool non_constant_args = false; |
cf72f34d | 1630 | cxx_bind_parameters_in_call (ctx, t, &new_call, |
c8f6aeb1 | 1631 | non_constant_p, overflow_p, &non_constant_args); |
09b42213 | 1632 | if (*non_constant_p) |
1633 | return t; | |
1634 | ||
1635 | depth_ok = push_cx_call_context (t); | |
1636 | ||
c8f6aeb1 | 1637 | tree result = NULL_TREE; |
09b42213 | 1638 | |
c8f6aeb1 | 1639 | constexpr_call *entry = NULL; |
167a09fb | 1640 | if (depth_ok && !non_constant_args && ctx->strict) |
09b42213 | 1641 | { |
c8f6aeb1 | 1642 | new_call.hash = iterative_hash_template_arg |
1643 | (new_call.bindings, constexpr_fundef_hasher::hash (new_call.fundef)); | |
1644 | ||
1645 | /* If we have seen this call before, we are done. */ | |
1646 | maybe_initialize_constexpr_call_table (); | |
1647 | constexpr_call **slot | |
1648 | = constexpr_call_table->find_slot (&new_call, INSERT); | |
1649 | entry = *slot; | |
1650 | if (entry == NULL) | |
1651 | { | |
1652 | /* We need to keep a pointer to the entry, not just the slot, as the | |
1653 | slot can move in the call to cxx_eval_builtin_function_call. */ | |
1654 | *slot = entry = ggc_alloc<constexpr_call> (); | |
1655 | *entry = new_call; | |
1656 | } | |
2ba934c7 | 1657 | /* Calls that are in progress have their result set to NULL, |
c8f6aeb1 | 1658 | so that we can detect circular dependencies. */ |
1659 | else if (entry->result == NULL) | |
1660 | { | |
1661 | if (!ctx->quiet) | |
1662 | error ("call has circular dependency"); | |
1663 | *non_constant_p = true; | |
1664 | entry->result = result = error_mark_node; | |
1665 | } | |
1666 | else | |
1667 | result = entry->result; | |
09b42213 | 1668 | } |
1669 | ||
1670 | if (!depth_ok) | |
1671 | { | |
f83e6885 | 1672 | if (!ctx->quiet) |
5967b28b | 1673 | error ("%<constexpr%> evaluation depth exceeds maximum of %d (use " |
09b42213 | 1674 | "-fconstexpr-depth= to increase the maximum)", |
1675 | max_constexpr_depth); | |
1676 | *non_constant_p = true; | |
c8f6aeb1 | 1677 | result = error_mark_node; |
09b42213 | 1678 | } |
1679 | else | |
1680 | { | |
ab099088 | 1681 | if (result && result != error_mark_node) |
1682 | /* OK */; | |
1683 | else if (!DECL_SAVED_TREE (fun)) | |
1684 | { | |
1685 | /* When at_eof >= 2, cgraph has started throwing away | |
1686 | DECL_SAVED_TREE, so fail quietly. FIXME we get here because of | |
1687 | late code generation for VEC_INIT_EXPR, which needs to be | |
1688 | completely reconsidered. */ | |
1689 | gcc_assert (at_eof >= 2 && ctx->quiet); | |
1690 | *non_constant_p = true; | |
1691 | } | |
1692 | else | |
cf72f34d | 1693 | { |
4f7ebe46 | 1694 | tree body, parms, res; |
88a59139 | 1695 | |
4f7ebe46 | 1696 | /* Reuse or create a new unshared copy of this function's body. */ |
a050099a | 1697 | tree copy = get_fundef_copy (fun); |
1698 | body = TREE_PURPOSE (copy); | |
1699 | parms = TREE_VALUE (copy); | |
1700 | res = TREE_TYPE (copy); | |
88a59139 | 1701 | |
1702 | /* Associate the bindings with the remapped parms. */ | |
1703 | tree bound = new_call.bindings; | |
1704 | tree remapped = parms; | |
1705 | while (bound) | |
9c96033c | 1706 | { |
88a59139 | 1707 | tree oparm = TREE_PURPOSE (bound); |
1708 | tree arg = TREE_VALUE (bound); | |
1709 | gcc_assert (DECL_NAME (remapped) == DECL_NAME (oparm)); | |
5898f0d7 | 1710 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 1711 | arg = unshare_constructor (arg); |
88a59139 | 1712 | ctx->values->put (remapped, arg); |
1713 | bound = TREE_CHAIN (bound); | |
1714 | remapped = DECL_CHAIN (remapped); | |
9c96033c | 1715 | } |
88a59139 | 1716 | /* Add the RESULT_DECL to the values map, too. */ |
1717 | tree slot = NULL_TREE; | |
1718 | if (DECL_BY_REFERENCE (res)) | |
9c96033c | 1719 | { |
88a59139 | 1720 | slot = AGGR_INIT_EXPR_SLOT (t); |
1721 | tree addr = build_address (slot); | |
1722 | addr = build_nop (TREE_TYPE (res), addr); | |
1723 | ctx->values->put (res, addr); | |
1724 | ctx->values->put (slot, NULL_TREE); | |
1725 | } | |
1726 | else | |
1727 | ctx->values->put (res, NULL_TREE); | |
9c96033c | 1728 | |
4f7ebe46 | 1729 | /* Track the callee's evaluated SAVE_EXPRs so that we can forget |
1730 | their values after the call. */ | |
1731 | constexpr_ctx ctx_with_save_exprs = *ctx; | |
1732 | hash_set<tree> save_exprs; | |
1733 | ctx_with_save_exprs.save_exprs = &save_exprs; | |
43b7271d | 1734 | ctx_with_save_exprs.call = &new_call; |
4f7ebe46 | 1735 | |
88a59139 | 1736 | tree jump_target = NULL_TREE; |
4f7ebe46 | 1737 | cxx_eval_constant_expression (&ctx_with_save_exprs, body, |
88a59139 | 1738 | lval, non_constant_p, overflow_p, |
1739 | &jump_target); | |
9c96033c | 1740 | |
88a59139 | 1741 | if (DECL_CONSTRUCTOR_P (fun)) |
1742 | /* This can be null for a subobject constructor call, in | |
1743 | which case what we care about is the initialization | |
1744 | side-effects rather than the value. We could get at the | |
1745 | value by evaluating *this, but we don't bother; there's | |
1746 | no need to put such a call in the hash table. */ | |
1747 | result = lval ? ctx->object : ctx->ctor; | |
1748 | else if (VOID_TYPE_P (TREE_TYPE (res))) | |
1749 | result = void_node; | |
1750 | else | |
1751 | { | |
1752 | result = *ctx->values->get (slot ? slot : res); | |
1753 | if (result == NULL_TREE && !*non_constant_p) | |
9c96033c | 1754 | { |
88a59139 | 1755 | if (!ctx->quiet) |
5967b28b | 1756 | error ("%<constexpr%> call flows off the end " |
88a59139 | 1757 | "of the function"); |
1758 | *non_constant_p = true; | |
9c96033c | 1759 | } |
9c96033c | 1760 | } |
88a59139 | 1761 | |
4f7ebe46 | 1762 | /* Forget the saved values of the callee's SAVE_EXPRs. */ |
1763 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
1764 | iter != save_exprs.end(); ++iter) | |
1765 | ctx_with_save_exprs.values->remove (*iter); | |
1766 | ||
88a59139 | 1767 | /* Remove the parms/result from the values map. Is it worth |
1768 | bothering to do this when the map itself is only live for | |
1769 | one constexpr evaluation? If so, maybe also clear out | |
1770 | other vars from call, maybe in BIND_EXPR handling? */ | |
1771 | ctx->values->remove (res); | |
1772 | if (slot) | |
1773 | ctx->values->remove (slot); | |
1774 | for (tree parm = parms; parm; parm = TREE_CHAIN (parm)) | |
1775 | ctx->values->remove (parm); | |
4f7ebe46 | 1776 | |
1777 | /* Make the unshared function copy we used available for re-use. */ | |
1778 | save_fundef_copy (fun, copy); | |
cf72f34d | 1779 | } |
9c96033c | 1780 | |
09b42213 | 1781 | if (result == error_mark_node) |
1782 | *non_constant_p = true; | |
c3f376bf | 1783 | if (*non_constant_p || *overflow_p) |
c8f6aeb1 | 1784 | result = error_mark_node; |
88a59139 | 1785 | else if (!result) |
9c96033c | 1786 | result = void_node; |
c8f6aeb1 | 1787 | if (entry) |
1788 | entry->result = result; | |
09b42213 | 1789 | } |
1790 | ||
c6d97004 | 1791 | /* The result of a constexpr function must be completely initialized. */ |
1792 | if (TREE_CODE (result) == CONSTRUCTOR) | |
79cdb4f5 | 1793 | clear_no_implicit_zero (result); |
c6d97004 | 1794 | |
09b42213 | 1795 | pop_cx_call_context (); |
e283bb4f | 1796 | return unshare_constructor (result); |
09b42213 | 1797 | } |
1798 | ||
1799 | /* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */ | |
1800 | ||
1801 | bool | |
1802 | reduced_constant_expression_p (tree t) | |
1803 | { | |
a34934c2 | 1804 | if (t == NULL_TREE) |
1805 | return false; | |
1806 | ||
09b42213 | 1807 | switch (TREE_CODE (t)) |
1808 | { | |
1809 | case PTRMEM_CST: | |
1810 | /* Even if we can't lower this yet, it's constant. */ | |
1811 | return true; | |
1812 | ||
1813 | case CONSTRUCTOR: | |
1814 | /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */ | |
56da7fe6 | 1815 | tree idx, val, field; unsigned HOST_WIDE_INT i; |
165d0d5b | 1816 | if (CONSTRUCTOR_NO_CLEARING (t)) |
c4210852 | 1817 | { |
1818 | if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE) | |
1819 | /* An initialized vector would have a VECTOR_CST. */ | |
1820 | return false; | |
1821 | else | |
1822 | field = next_initializable_field (TYPE_FIELDS (TREE_TYPE (t))); | |
1823 | } | |
56da7fe6 | 1824 | else |
1825 | field = NULL_TREE; | |
1826 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t), i, idx, val) | |
ce4ffd9e | 1827 | { |
a34934c2 | 1828 | /* If VAL is null, we're in the middle of initializing this |
1829 | element. */ | |
56da7fe6 | 1830 | if (!reduced_constant_expression_p (val)) |
ce4ffd9e | 1831 | return false; |
56da7fe6 | 1832 | if (field) |
1833 | { | |
1834 | if (idx != field) | |
1835 | return false; | |
1836 | field = next_initializable_field (DECL_CHAIN (field)); | |
1837 | } | |
ce4ffd9e | 1838 | } |
56da7fe6 | 1839 | if (field) |
1840 | return false; | |
165d0d5b | 1841 | else if (CONSTRUCTOR_NO_CLEARING (t)) |
56da7fe6 | 1842 | /* All the fields are initialized. */ |
165d0d5b | 1843 | CONSTRUCTOR_NO_CLEARING (t) = false; |
09b42213 | 1844 | return true; |
1845 | ||
1846 | default: | |
1847 | /* FIXME are we calling this too much? */ | |
1848 | return initializer_constant_valid_p (t, TREE_TYPE (t)) != NULL_TREE; | |
1849 | } | |
1850 | } | |
1851 | ||
1852 | /* Some expressions may have constant operands but are not constant | |
941fafa5 | 1853 | themselves, such as 1/0. Call this function to check for that |
1854 | condition. | |
09b42213 | 1855 | |
1856 | We only call this in places that require an arithmetic constant, not in | |
1857 | places where we might have a non-constant expression that can be a | |
1858 | component of a constant expression, such as the address of a constexpr | |
1859 | variable that might be dereferenced later. */ | |
1860 | ||
1861 | static bool | |
1862 | verify_constant (tree t, bool allow_non_constant, bool *non_constant_p, | |
1863 | bool *overflow_p) | |
1864 | { | |
1865 | if (!*non_constant_p && !reduced_constant_expression_p (t)) | |
1866 | { | |
1867 | if (!allow_non_constant) | |
1868 | error ("%q+E is not a constant expression", t); | |
1869 | *non_constant_p = true; | |
1870 | } | |
1871 | if (TREE_OVERFLOW_P (t)) | |
1872 | { | |
1873 | if (!allow_non_constant) | |
1874 | { | |
1875 | permerror (input_location, "overflow in constant expression"); | |
1876 | /* If we're being permissive (and are in an enforcing | |
1877 | context), ignore the overflow. */ | |
1878 | if (flag_permissive) | |
1879 | return *non_constant_p; | |
1880 | } | |
1881 | *overflow_p = true; | |
1882 | } | |
1883 | return *non_constant_p; | |
1884 | } | |
1885 | ||
2b035ffe | 1886 | /* Check whether the shift operation with code CODE and type TYPE on LHS |
1887 | and RHS is undefined. If it is, give an error with an explanation, | |
1888 | and return true; return false otherwise. */ | |
1889 | ||
1890 | static bool | |
1891 | cxx_eval_check_shift_p (location_t loc, const constexpr_ctx *ctx, | |
1892 | enum tree_code code, tree type, tree lhs, tree rhs) | |
1893 | { | |
1894 | if ((code != LSHIFT_EXPR && code != RSHIFT_EXPR) | |
1895 | || TREE_CODE (lhs) != INTEGER_CST | |
1896 | || TREE_CODE (rhs) != INTEGER_CST) | |
1897 | return false; | |
1898 | ||
1899 | tree lhstype = TREE_TYPE (lhs); | |
1900 | unsigned HOST_WIDE_INT uprec = TYPE_PRECISION (TREE_TYPE (lhs)); | |
1901 | ||
1902 | /* [expr.shift] The behavior is undefined if the right operand | |
1903 | is negative, or greater than or equal to the length in bits | |
1904 | of the promoted left operand. */ | |
1905 | if (tree_int_cst_sgn (rhs) == -1) | |
1906 | { | |
1907 | if (!ctx->quiet) | |
91d87e22 | 1908 | permerror (loc, "right operand of shift expression %q+E is negative", |
1909 | build2_loc (loc, code, type, lhs, rhs)); | |
1910 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1911 | } |
1912 | if (compare_tree_int (rhs, uprec) >= 0) | |
1913 | { | |
1914 | if (!ctx->quiet) | |
91d87e22 | 1915 | permerror (loc, "right operand of shift expression %q+E is >= than " |
1916 | "the precision of the left operand", | |
1917 | build2_loc (loc, code, type, lhs, rhs)); | |
1918 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1919 | } |
1920 | ||
1921 | /* The value of E1 << E2 is E1 left-shifted E2 bit positions; [...] | |
1922 | if E1 has a signed type and non-negative value, and E1x2^E2 is | |
1923 | representable in the corresponding unsigned type of the result type, | |
1924 | then that value, converted to the result type, is the resulting value; | |
1925 | otherwise, the behavior is undefined. */ | |
1926 | if (code == LSHIFT_EXPR && !TYPE_UNSIGNED (lhstype) | |
1927 | && (cxx_dialect >= cxx11)) | |
1928 | { | |
1929 | if (tree_int_cst_sgn (lhs) == -1) | |
1930 | { | |
1931 | if (!ctx->quiet) | |
91d87e22 | 1932 | permerror (loc, |
1933 | "left operand of shift expression %q+E is negative", | |
1934 | build2_loc (loc, code, type, lhs, rhs)); | |
1935 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1936 | } |
1937 | /* For signed x << y the following: | |
1938 | (unsigned) x >> ((prec (lhs) - 1) - y) | |
1939 | if > 1, is undefined. The right-hand side of this formula | |
1940 | is the highest bit of the LHS that can be set (starting from 0), | |
1941 | so that the shift doesn't overflow. We then right-shift the LHS | |
1942 | to see whether any other bit is set making the original shift | |
1943 | undefined -- the result is not representable in the corresponding | |
1944 | unsigned type. */ | |
1945 | tree t = build_int_cst (unsigned_type_node, uprec - 1); | |
1946 | t = fold_build2 (MINUS_EXPR, unsigned_type_node, t, rhs); | |
1947 | tree ulhs = fold_convert (unsigned_type_for (lhstype), lhs); | |
1948 | t = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ulhs), ulhs, t); | |
1949 | if (tree_int_cst_lt (integer_one_node, t)) | |
1950 | { | |
1951 | if (!ctx->quiet) | |
91d87e22 | 1952 | permerror (loc, "shift expression %q+E overflows", |
1953 | build2_loc (loc, code, type, lhs, rhs)); | |
1954 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1955 | } |
1956 | } | |
1957 | return false; | |
1958 | } | |
1959 | ||
09b42213 | 1960 | /* Subroutine of cxx_eval_constant_expression. |
1961 | Attempt to reduce the unary expression tree T to a compile time value. | |
1962 | If successful, return the value. Otherwise issue a diagnostic | |
1963 | and return error_mark_node. */ | |
1964 | ||
1965 | static tree | |
cf72f34d | 1966 | cxx_eval_unary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 1967 | bool /*lval*/, |
09b42213 | 1968 | bool *non_constant_p, bool *overflow_p) |
1969 | { | |
1970 | tree r; | |
1971 | tree orig_arg = TREE_OPERAND (t, 0); | |
c8f6aeb1 | 1972 | tree arg = cxx_eval_constant_expression (ctx, orig_arg, /*lval*/false, |
1973 | non_constant_p, overflow_p); | |
09b42213 | 1974 | VERIFY_CONSTANT (arg); |
93add516 | 1975 | location_t loc = EXPR_LOCATION (t); |
1976 | enum tree_code code = TREE_CODE (t); | |
1977 | tree type = TREE_TYPE (t); | |
1978 | r = fold_unary_loc (loc, code, type, arg); | |
1979 | if (r == NULL_TREE) | |
1980 | { | |
1981 | if (arg == orig_arg) | |
1982 | r = t; | |
1983 | else | |
1984 | r = build1_loc (loc, code, type, arg); | |
1985 | } | |
09b42213 | 1986 | VERIFY_CONSTANT (r); |
1987 | return r; | |
1988 | } | |
1989 | ||
46fad8d5 | 1990 | /* Helper function for cxx_eval_binary_expression. Try to optimize |
1991 | original POINTER_PLUS_EXPR T, LHS p+ RHS, return NULL_TREE if the | |
1992 | generic folding should be used. */ | |
1993 | ||
1994 | static tree | |
1995 | cxx_fold_pointer_plus_expression (const constexpr_ctx *ctx, tree t, | |
1996 | tree lhs, tree rhs, bool *non_constant_p, | |
1997 | bool *overflow_p) | |
1998 | { | |
1999 | STRIP_NOPS (lhs); | |
2000 | if (TREE_CODE (lhs) != ADDR_EXPR) | |
2001 | return NULL_TREE; | |
2002 | ||
2003 | lhs = TREE_OPERAND (lhs, 0); | |
2004 | ||
2005 | /* &A[i] p+ j => &A[i + j] */ | |
2006 | if (TREE_CODE (lhs) == ARRAY_REF | |
2007 | && TREE_CODE (TREE_OPERAND (lhs, 1)) == INTEGER_CST | |
2008 | && TREE_CODE (rhs) == INTEGER_CST | |
2009 | && TYPE_SIZE_UNIT (TREE_TYPE (lhs)) | |
2010 | && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (lhs))) == INTEGER_CST) | |
2011 | { | |
2012 | tree orig_type = TREE_TYPE (t); | |
2013 | location_t loc = EXPR_LOCATION (t); | |
2014 | tree type = TREE_TYPE (lhs); | |
2015 | ||
2016 | t = fold_convert_loc (loc, ssizetype, TREE_OPERAND (lhs, 1)); | |
2017 | tree nelts = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (lhs, 0))); | |
2018 | nelts = cxx_eval_constant_expression (ctx, nelts, false, non_constant_p, | |
2019 | overflow_p); | |
2020 | if (*non_constant_p) | |
2021 | return NULL_TREE; | |
2022 | /* Don't fold an out-of-bound access. */ | |
2023 | if (!tree_int_cst_le (t, nelts)) | |
2024 | return NULL_TREE; | |
2025 | rhs = cp_fold_convert (ssizetype, rhs); | |
2026 | /* Don't fold if rhs can't be divided exactly by TYPE_SIZE_UNIT. | |
2027 | constexpr int A[1]; ... (char *)&A[0] + 1 */ | |
2028 | if (!integer_zerop (fold_build2_loc (loc, TRUNC_MOD_EXPR, sizetype, | |
2029 | rhs, TYPE_SIZE_UNIT (type)))) | |
2030 | return NULL_TREE; | |
2031 | /* Make sure to treat the second operand of POINTER_PLUS_EXPR | |
2032 | as signed. */ | |
2033 | rhs = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, rhs, | |
2034 | TYPE_SIZE_UNIT (type)); | |
2035 | t = size_binop_loc (loc, PLUS_EXPR, rhs, t); | |
2036 | t = build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (lhs, 0), | |
2037 | t, NULL_TREE, NULL_TREE); | |
2038 | t = cp_build_addr_expr (t, tf_warning_or_error); | |
2039 | t = cp_fold_convert (orig_type, t); | |
2040 | return cxx_eval_constant_expression (ctx, t, /*lval*/false, | |
2041 | non_constant_p, overflow_p); | |
2042 | } | |
2043 | ||
2044 | return NULL_TREE; | |
2045 | } | |
2046 | ||
09b42213 | 2047 | /* Subroutine of cxx_eval_constant_expression. |
2048 | Like cxx_eval_unary_expression, except for binary expressions. */ | |
2049 | ||
2050 | static tree | |
cf72f34d | 2051 | cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 2052 | bool /*lval*/, |
09b42213 | 2053 | bool *non_constant_p, bool *overflow_p) |
2054 | { | |
f7ef5392 | 2055 | tree r = NULL_TREE; |
09b42213 | 2056 | tree orig_lhs = TREE_OPERAND (t, 0); |
2057 | tree orig_rhs = TREE_OPERAND (t, 1); | |
2058 | tree lhs, rhs; | |
c8f6aeb1 | 2059 | lhs = cxx_eval_constant_expression (ctx, orig_lhs, /*lval*/false, |
b2a43197 | 2060 | non_constant_p, overflow_p); |
6d6737d9 | 2061 | /* Don't VERIFY_CONSTANT here, it's unnecessary and will break pointer |
2062 | subtraction. */ | |
2063 | if (*non_constant_p) | |
2064 | return t; | |
c8f6aeb1 | 2065 | rhs = cxx_eval_constant_expression (ctx, orig_rhs, /*lval*/false, |
b2a43197 | 2066 | non_constant_p, overflow_p); |
6d6737d9 | 2067 | if (*non_constant_p) |
2068 | return t; | |
93add516 | 2069 | |
2070 | location_t loc = EXPR_LOCATION (t); | |
2071 | enum tree_code code = TREE_CODE (t); | |
2072 | tree type = TREE_TYPE (t); | |
f7ef5392 | 2073 | |
2074 | if (code == EQ_EXPR || code == NE_EXPR) | |
2075 | { | |
2076 | bool is_code_eq = (code == EQ_EXPR); | |
2077 | ||
2078 | if (TREE_CODE (lhs) == PTRMEM_CST | |
2079 | && TREE_CODE (rhs) == PTRMEM_CST) | |
e9f29fe5 | 2080 | { |
2081 | tree lmem = PTRMEM_CST_MEMBER (lhs); | |
2082 | tree rmem = PTRMEM_CST_MEMBER (rhs); | |
2083 | bool eq; | |
2084 | if (TREE_CODE (lmem) == TREE_CODE (rmem) | |
2085 | && TREE_CODE (lmem) == FIELD_DECL | |
2086 | && TREE_CODE (DECL_CONTEXT (lmem)) == UNION_TYPE | |
2087 | && same_type_p (DECL_CONTEXT (lmem), | |
2088 | DECL_CONTEXT (rmem))) | |
2089 | /* If both refer to (possibly different) members of the same union | |
2090 | (12.3), they compare equal. */ | |
2091 | eq = true; | |
2092 | else | |
2093 | eq = cp_tree_equal (lhs, rhs); | |
2094 | r = constant_boolean_node (eq == is_code_eq, type); | |
2095 | } | |
f7ef5392 | 2096 | else if ((TREE_CODE (lhs) == PTRMEM_CST |
2097 | || TREE_CODE (rhs) == PTRMEM_CST) | |
2098 | && (null_member_pointer_value_p (lhs) | |
2099 | || null_member_pointer_value_p (rhs))) | |
2100 | r = constant_boolean_node (!is_code_eq, type); | |
f31f4e9c | 2101 | else if (TREE_CODE (lhs) == PTRMEM_CST) |
2102 | lhs = cplus_expand_constant (lhs); | |
2103 | else if (TREE_CODE (rhs) == PTRMEM_CST) | |
2104 | rhs = cplus_expand_constant (rhs); | |
f7ef5392 | 2105 | } |
cb768824 | 2106 | if (code == POINTER_PLUS_EXPR && !*non_constant_p |
2107 | && integer_zerop (lhs) && !integer_zerop (rhs)) | |
2108 | { | |
2109 | if (!ctx->quiet) | |
2110 | error ("arithmetic involving a null pointer in %qE", lhs); | |
2b1749c4 | 2111 | *non_constant_p = true; |
cb768824 | 2112 | return t; |
2113 | } | |
46fad8d5 | 2114 | else if (code == POINTER_PLUS_EXPR) |
2115 | r = cxx_fold_pointer_plus_expression (ctx, t, lhs, rhs, non_constant_p, | |
2116 | overflow_p); | |
f7ef5392 | 2117 | |
2118 | if (r == NULL_TREE) | |
2119 | r = fold_binary_loc (loc, code, type, lhs, rhs); | |
2120 | ||
93add516 | 2121 | if (r == NULL_TREE) |
2122 | { | |
2123 | if (lhs == orig_lhs && rhs == orig_rhs) | |
2124 | r = t; | |
2125 | else | |
2126 | r = build2_loc (loc, code, type, lhs, rhs); | |
2127 | } | |
2b035ffe | 2128 | else if (cxx_eval_check_shift_p (loc, ctx, code, type, lhs, rhs)) |
2129 | *non_constant_p = true; | |
6d6737d9 | 2130 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
2131 | a local array in a constexpr function. */ | |
d03fa520 | 2132 | bool ptr = INDIRECT_TYPE_P (TREE_TYPE (lhs)); |
35f2c28f | 2133 | if (!ptr) |
aae7465c | 2134 | VERIFY_CONSTANT (r); |
09b42213 | 2135 | return r; |
2136 | } | |
2137 | ||
2138 | /* Subroutine of cxx_eval_constant_expression. | |
2139 | Attempt to evaluate condition expressions. Dead branches are not | |
2140 | looked into. */ | |
2141 | ||
2142 | static tree | |
cf72f34d | 2143 | cxx_eval_conditional_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2144 | bool lval, |
00f21715 | 2145 | bool *non_constant_p, bool *overflow_p, |
2146 | tree *jump_target) | |
09b42213 | 2147 | { |
cf72f34d | 2148 | tree val = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
c8f6aeb1 | 2149 | /*lval*/false, |
b2a43197 | 2150 | non_constant_p, overflow_p); |
09b42213 | 2151 | VERIFY_CONSTANT (val); |
2152 | /* Don't VERIFY_CONSTANT the other operands. */ | |
2153 | if (integer_zerop (val)) | |
cf72f34d | 2154 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), |
1227ba74 | 2155 | lval, |
00f21715 | 2156 | non_constant_p, overflow_p, |
2157 | jump_target); | |
cf72f34d | 2158 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2159 | lval, |
00f21715 | 2160 | non_constant_p, overflow_p, |
2161 | jump_target); | |
09b42213 | 2162 | } |
2163 | ||
31595caf | 2164 | /* Subroutine of cxx_eval_constant_expression. |
2165 | Attempt to evaluate vector condition expressions. Unlike | |
2166 | cxx_eval_conditional_expression, VEC_COND_EXPR acts like a normal | |
2167 | ternary arithmetics operation, where all 3 arguments have to be | |
2168 | evaluated as constants and then folding computes the result from | |
2169 | them. */ | |
2170 | ||
2171 | static tree | |
2172 | cxx_eval_vector_conditional_expression (const constexpr_ctx *ctx, tree t, | |
2173 | bool *non_constant_p, bool *overflow_p) | |
2174 | { | |
2175 | tree arg1 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
2176 | /*lval*/false, | |
2177 | non_constant_p, overflow_p); | |
2178 | VERIFY_CONSTANT (arg1); | |
2179 | tree arg2 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
2180 | /*lval*/false, | |
2181 | non_constant_p, overflow_p); | |
2182 | VERIFY_CONSTANT (arg2); | |
2183 | tree arg3 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
2184 | /*lval*/false, | |
2185 | non_constant_p, overflow_p); | |
2186 | VERIFY_CONSTANT (arg3); | |
2187 | location_t loc = EXPR_LOCATION (t); | |
2188 | tree type = TREE_TYPE (t); | |
2189 | tree r = fold_ternary_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2190 | if (r == NULL_TREE) | |
2191 | { | |
2192 | if (arg1 == TREE_OPERAND (t, 0) | |
2193 | && arg2 == TREE_OPERAND (t, 1) | |
2194 | && arg3 == TREE_OPERAND (t, 2)) | |
2195 | r = t; | |
2196 | else | |
2197 | r = build3_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2198 | } | |
2199 | VERIFY_CONSTANT (r); | |
2200 | return r; | |
2201 | } | |
2202 | ||
7963b19d | 2203 | /* Returns less than, equal to, or greater than zero if KEY is found to be |
2204 | less than, to match, or to be greater than the constructor_elt's INDEX. */ | |
2205 | ||
2206 | static int | |
2207 | array_index_cmp (tree key, tree index) | |
2208 | { | |
2209 | gcc_assert (TREE_CODE (key) == INTEGER_CST); | |
2210 | ||
2211 | switch (TREE_CODE (index)) | |
2212 | { | |
2213 | case INTEGER_CST: | |
2214 | return tree_int_cst_compare (key, index); | |
2215 | case RANGE_EXPR: | |
2216 | { | |
2217 | tree lo = TREE_OPERAND (index, 0); | |
2218 | tree hi = TREE_OPERAND (index, 1); | |
2219 | if (tree_int_cst_lt (key, lo)) | |
2220 | return -1; | |
2221 | else if (tree_int_cst_lt (hi, key)) | |
2222 | return 1; | |
2223 | else | |
2224 | return 0; | |
2225 | } | |
2226 | default: | |
2227 | gcc_unreachable (); | |
2228 | } | |
2229 | } | |
2230 | ||
2231 | /* Returns the index of the constructor_elt of ARY which matches DINDEX, or -1 | |
2232 | if none. If INSERT is true, insert a matching element rather than fail. */ | |
2233 | ||
2234 | static HOST_WIDE_INT | |
2235 | find_array_ctor_elt (tree ary, tree dindex, bool insert = false) | |
2236 | { | |
2237 | if (tree_int_cst_sgn (dindex) < 0) | |
2238 | return -1; | |
2239 | ||
2240 | unsigned HOST_WIDE_INT i = tree_to_uhwi (dindex); | |
2241 | vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (ary); | |
2242 | unsigned HOST_WIDE_INT len = vec_safe_length (elts); | |
2243 | ||
2244 | unsigned HOST_WIDE_INT end = len; | |
2245 | unsigned HOST_WIDE_INT begin = 0; | |
2246 | ||
2247 | /* If the last element of the CONSTRUCTOR has its own index, we can assume | |
2248 | that the same is true of the other elements and index directly. */ | |
2249 | if (end > 0) | |
2250 | { | |
e99466d6 | 2251 | tree cindex = (*elts)[end - 1].index; |
7963b19d | 2252 | if (TREE_CODE (cindex) == INTEGER_CST |
e99466d6 | 2253 | && compare_tree_int (cindex, end - 1) == 0) |
7963b19d | 2254 | { |
2255 | if (i < end) | |
2256 | return i; | |
2257 | else | |
2258 | begin = end; | |
2259 | } | |
2260 | } | |
2261 | ||
2262 | /* Otherwise, find a matching index by means of a binary search. */ | |
2263 | while (begin != end) | |
2264 | { | |
2265 | unsigned HOST_WIDE_INT middle = (begin + end) / 2; | |
f0b916c7 | 2266 | constructor_elt &elt = (*elts)[middle]; |
2267 | tree idx = elt.index; | |
7963b19d | 2268 | |
f0b916c7 | 2269 | int cmp = array_index_cmp (dindex, idx); |
7963b19d | 2270 | if (cmp < 0) |
2271 | end = middle; | |
2272 | else if (cmp > 0) | |
2273 | begin = middle + 1; | |
2274 | else | |
f0b916c7 | 2275 | { |
2276 | if (insert && TREE_CODE (idx) == RANGE_EXPR) | |
2277 | { | |
2278 | /* We need to split the range. */ | |
2279 | constructor_elt e; | |
2280 | tree lo = TREE_OPERAND (idx, 0); | |
2281 | tree hi = TREE_OPERAND (idx, 1); | |
e99466d6 | 2282 | tree value = elt.value; |
2283 | dindex = fold_convert (sizetype, dindex); | |
f0b916c7 | 2284 | if (tree_int_cst_lt (lo, dindex)) |
2285 | { | |
2286 | /* There are still some lower elts; shorten the range. */ | |
2287 | tree new_hi = int_const_binop (MINUS_EXPR, dindex, | |
2288 | size_one_node); | |
2289 | if (tree_int_cst_equal (lo, new_hi)) | |
2290 | /* Only one element left, no longer a range. */ | |
2291 | elt.index = lo; | |
2292 | else | |
2293 | TREE_OPERAND (idx, 1) = new_hi; | |
2294 | /* Append the element we want to insert. */ | |
2295 | ++middle; | |
2296 | e.index = dindex; | |
e99466d6 | 2297 | e.value = unshare_constructor (value); |
f0b916c7 | 2298 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle, e); |
2299 | } | |
2300 | else | |
2301 | /* No lower elts, the range elt is now ours. */ | |
2302 | elt.index = dindex; | |
2303 | ||
2304 | if (tree_int_cst_lt (dindex, hi)) | |
2305 | { | |
2306 | /* There are still some higher elts; append a range. */ | |
2307 | tree new_lo = int_const_binop (PLUS_EXPR, dindex, | |
2308 | size_one_node); | |
2309 | if (tree_int_cst_equal (new_lo, hi)) | |
2310 | e.index = hi; | |
2311 | else | |
2312 | e.index = build2 (RANGE_EXPR, sizetype, new_lo, hi); | |
e99466d6 | 2313 | e.value = unshare_constructor (value); |
2314 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle + 1, e); | |
f0b916c7 | 2315 | } |
2316 | } | |
2317 | return middle; | |
2318 | } | |
7963b19d | 2319 | } |
2320 | ||
2321 | if (insert) | |
2322 | { | |
2323 | constructor_elt e = { dindex, NULL_TREE }; | |
2324 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), end, e); | |
2325 | return end; | |
2326 | } | |
2327 | ||
2328 | return -1; | |
2329 | } | |
2330 | ||
40df9099 | 2331 | /* Under the control of CTX, issue a detailed diagnostic for |
2332 | an out-of-bounds subscript INDEX into the expression ARRAY. */ | |
2333 | ||
2334 | static void | |
2335 | diag_array_subscript (const constexpr_ctx *ctx, tree array, tree index) | |
2336 | { | |
2337 | if (!ctx->quiet) | |
2338 | { | |
2339 | tree arraytype = TREE_TYPE (array); | |
2340 | ||
2341 | /* Convert the unsigned array subscript to a signed integer to avoid | |
2342 | printing huge numbers for small negative values. */ | |
2343 | tree sidx = fold_convert (ssizetype, index); | |
2344 | if (DECL_P (array)) | |
2345 | { | |
d7d265db | 2346 | if (TYPE_DOMAIN (arraytype)) |
2347 | error ("array subscript value %qE is outside the bounds " | |
2348 | "of array %qD of type %qT", sidx, array, arraytype); | |
2349 | else | |
2350 | error ("non-zero array subscript %qE is used with array %qD of " | |
2351 | "type %qT with unknown bounds", sidx, array, arraytype); | |
40df9099 | 2352 | inform (DECL_SOURCE_LOCATION (array), "declared here"); |
2353 | } | |
d7d265db | 2354 | else if (TYPE_DOMAIN (arraytype)) |
40df9099 | 2355 | error ("array subscript value %qE is outside the bounds " |
2356 | "of array type %qT", sidx, arraytype); | |
d7d265db | 2357 | else |
2358 | error ("non-zero array subscript %qE is used with array of type %qT " | |
2359 | "with unknown bounds", sidx, arraytype); | |
40df9099 | 2360 | } |
2361 | } | |
7963b19d | 2362 | |
51f0c7e2 | 2363 | /* Return the number of elements for TYPE (which is an ARRAY_TYPE or |
2364 | a VECTOR_TYPE). */ | |
2365 | ||
2366 | static tree | |
2367 | get_array_or_vector_nelts (const constexpr_ctx *ctx, tree type, | |
2368 | bool *non_constant_p, bool *overflow_p) | |
2369 | { | |
2370 | tree nelts; | |
2371 | if (TREE_CODE (type) == ARRAY_TYPE) | |
2372 | { | |
2373 | if (TYPE_DOMAIN (type)) | |
2374 | nelts = array_type_nelts_top (type); | |
2375 | else | |
2376 | nelts = size_zero_node; | |
2377 | } | |
2378 | else if (VECTOR_TYPE_P (type)) | |
2379 | nelts = size_int (TYPE_VECTOR_SUBPARTS (type)); | |
2380 | else | |
2381 | gcc_unreachable (); | |
2382 | ||
2383 | /* For VLAs, the number of elements won't be an integer constant. */ | |
2384 | nelts = cxx_eval_constant_expression (ctx, nelts, false, | |
2385 | non_constant_p, overflow_p); | |
2386 | return nelts; | |
2387 | } | |
2388 | ||
92fe8840 | 2389 | /* Extract element INDEX consisting of CHARS_PER_ELT chars from |
2390 | STRING_CST STRING. */ | |
2391 | ||
2392 | static tree | |
2393 | extract_string_elt (tree string, unsigned chars_per_elt, unsigned index) | |
2394 | { | |
2395 | tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (string))); | |
2396 | tree r; | |
2397 | ||
2398 | if (chars_per_elt == 1) | |
2399 | r = build_int_cst (type, TREE_STRING_POINTER (string)[index]); | |
2400 | else | |
2401 | { | |
2402 | const unsigned char *ptr | |
2403 | = ((const unsigned char *)TREE_STRING_POINTER (string) | |
2404 | + index * chars_per_elt); | |
2405 | r = native_interpret_expr (type, ptr, chars_per_elt); | |
2406 | } | |
2407 | return r; | |
2408 | } | |
2409 | ||
09b42213 | 2410 | /* Subroutine of cxx_eval_constant_expression. |
2411 | Attempt to reduce a reference to an array slot. */ | |
2412 | ||
2413 | static tree | |
cf72f34d | 2414 | cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2415 | bool lval, |
09b42213 | 2416 | bool *non_constant_p, bool *overflow_p) |
2417 | { | |
2418 | tree oldary = TREE_OPERAND (t, 0); | |
cf72f34d | 2419 | tree ary = cxx_eval_constant_expression (ctx, oldary, |
1227ba74 | 2420 | lval, |
b2a43197 | 2421 | non_constant_p, overflow_p); |
09b42213 | 2422 | tree index, oldidx; |
cf3cefc9 | 2423 | HOST_WIDE_INT i = 0; |
2424 | tree elem_type = NULL_TREE; | |
2425 | unsigned len = 0, elem_nchars = 1; | |
09b42213 | 2426 | if (*non_constant_p) |
2427 | return t; | |
2428 | oldidx = TREE_OPERAND (t, 1); | |
cf72f34d | 2429 | index = cxx_eval_constant_expression (ctx, oldidx, |
f83e6885 | 2430 | false, |
b2a43197 | 2431 | non_constant_p, overflow_p); |
09b42213 | 2432 | VERIFY_CONSTANT (index); |
cf3cefc9 | 2433 | if (!lval) |
09b42213 | 2434 | { |
cf3cefc9 | 2435 | elem_type = TREE_TYPE (TREE_TYPE (ary)); |
2436 | if (TREE_CODE (ary) == VIEW_CONVERT_EXPR | |
2437 | && VECTOR_TYPE_P (TREE_TYPE (TREE_OPERAND (ary, 0))) | |
2438 | && TREE_TYPE (t) == TREE_TYPE (TREE_TYPE (TREE_OPERAND (ary, 0)))) | |
2439 | ary = TREE_OPERAND (ary, 0); | |
2440 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2441 | len = CONSTRUCTOR_NELTS (ary); | |
2442 | else if (TREE_CODE (ary) == STRING_CST) | |
2443 | { | |
2444 | elem_nchars = (TYPE_PRECISION (elem_type) | |
2445 | / TYPE_PRECISION (char_type_node)); | |
2446 | len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars; | |
2447 | } | |
2448 | else if (TREE_CODE (ary) == VECTOR_CST) | |
f08ee65f | 2449 | /* We don't create variable-length VECTOR_CSTs. */ |
2450 | len = VECTOR_CST_NELTS (ary).to_constant (); | |
cf3cefc9 | 2451 | else |
2452 | { | |
2453 | /* We can't do anything with other tree codes, so use | |
2454 | VERIFY_CONSTANT to complain and fail. */ | |
2455 | VERIFY_CONSTANT (ary); | |
2456 | gcc_unreachable (); | |
2457 | } | |
aed8dc7f | 2458 | |
cf3cefc9 | 2459 | if (!tree_fits_shwi_p (index) |
2460 | || (i = tree_to_shwi (index)) < 0) | |
2461 | { | |
2462 | diag_array_subscript (ctx, ary, index); | |
2463 | *non_constant_p = true; | |
2464 | return t; | |
2465 | } | |
7963b19d | 2466 | } |
2467 | ||
51f0c7e2 | 2468 | tree nelts = get_array_or_vector_nelts (ctx, TREE_TYPE (ary), non_constant_p, |
2469 | overflow_p); | |
ce6a6978 | 2470 | VERIFY_CONSTANT (nelts); |
0acc6340 | 2471 | if ((lval |
2472 | ? !tree_int_cst_le (index, nelts) | |
2473 | : !tree_int_cst_lt (index, nelts)) | |
2474 | || tree_int_cst_sgn (index) < 0) | |
ce6a6978 | 2475 | { |
40df9099 | 2476 | diag_array_subscript (ctx, ary, index); |
ce6a6978 | 2477 | *non_constant_p = true; |
2478 | return t; | |
2479 | } | |
2480 | ||
cf3cefc9 | 2481 | if (lval && ary == oldary && index == oldidx) |
2482 | return t; | |
2483 | else if (lval) | |
2484 | return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL); | |
2485 | ||
7963b19d | 2486 | bool found; |
2487 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2488 | { | |
2489 | HOST_WIDE_INT ix = find_array_ctor_elt (ary, index); | |
2490 | found = (ix >= 0); | |
2491 | if (found) | |
2492 | i = ix; | |
aed8dc7f | 2493 | } |
7963b19d | 2494 | else |
2495 | found = (i < len); | |
aed8dc7f | 2496 | |
14869f28 | 2497 | if (found) |
2498 | { | |
2499 | tree r; | |
2500 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2501 | r = (*CONSTRUCTOR_ELTS (ary))[i].value; | |
2502 | else if (TREE_CODE (ary) == VECTOR_CST) | |
2503 | r = VECTOR_CST_ELT (ary, i); | |
14869f28 | 2504 | else |
92fe8840 | 2505 | r = extract_string_elt (ary, elem_nchars, i); |
2506 | ||
14869f28 | 2507 | if (r) |
2508 | /* Don't VERIFY_CONSTANT here. */ | |
2509 | return r; | |
09b42213 | 2510 | |
14869f28 | 2511 | /* Otherwise the element doesn't have a value yet. */ |
09b42213 | 2512 | } |
aed8dc7f | 2513 | |
14869f28 | 2514 | /* Not found. */ |
2515 | ||
2516 | if (TREE_CODE (ary) == CONSTRUCTOR | |
165d0d5b | 2517 | && CONSTRUCTOR_NO_CLEARING (ary)) |
09b42213 | 2518 | { |
14869f28 | 2519 | /* 'ary' is part of the aggregate initializer we're currently |
2520 | building; if there's no initializer for this element yet, | |
2521 | that's an error. */ | |
2522 | if (!ctx->quiet) | |
2523 | error ("accessing uninitialized array element"); | |
2524 | *non_constant_p = true; | |
2525 | return t; | |
09b42213 | 2526 | } |
14869f28 | 2527 | |
2528 | /* If it's within the array bounds but doesn't have an explicit | |
2529 | initializer, it's value-initialized. */ | |
2530 | tree val = build_value_init (elem_type, tf_warning_or_error); | |
2531 | return cxx_eval_constant_expression (ctx, val, lval, non_constant_p, | |
2532 | overflow_p); | |
09b42213 | 2533 | } |
2534 | ||
2535 | /* Subroutine of cxx_eval_constant_expression. | |
2536 | Attempt to reduce a field access of a value of class type. */ | |
2537 | ||
2538 | static tree | |
cf72f34d | 2539 | cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2540 | bool lval, |
09b42213 | 2541 | bool *non_constant_p, bool *overflow_p) |
2542 | { | |
2543 | unsigned HOST_WIDE_INT i; | |
2544 | tree field; | |
2545 | tree value; | |
2546 | tree part = TREE_OPERAND (t, 1); | |
2547 | tree orig_whole = TREE_OPERAND (t, 0); | |
cf72f34d | 2548 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2549 | lval, |
b2a43197 | 2550 | non_constant_p, overflow_p); |
7ab20d7c | 2551 | if (INDIRECT_REF_P (whole) |
2b1749c4 | 2552 | && integer_zerop (TREE_OPERAND (whole, 0))) |
2553 | { | |
2554 | if (!ctx->quiet) | |
2555 | error ("dereferencing a null pointer in %qE", orig_whole); | |
2556 | *non_constant_p = true; | |
2557 | return t; | |
2558 | } | |
cb768824 | 2559 | |
f16ed232 | 2560 | if (TREE_CODE (whole) == PTRMEM_CST) |
2561 | whole = cplus_expand_constant (whole); | |
09b42213 | 2562 | if (whole == orig_whole) |
2563 | return t; | |
1227ba74 | 2564 | if (lval) |
09b42213 | 2565 | return fold_build3 (COMPONENT_REF, TREE_TYPE (t), |
2566 | whole, part, NULL_TREE); | |
2567 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2568 | CONSTRUCTOR. */ | |
2569 | if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR) | |
2570 | { | |
f83e6885 | 2571 | if (!ctx->quiet) |
09b42213 | 2572 | error ("%qE is not a constant expression", orig_whole); |
2573 | *non_constant_p = true; | |
2574 | } | |
2575 | if (DECL_MUTABLE_P (part)) | |
2576 | { | |
f83e6885 | 2577 | if (!ctx->quiet) |
09b42213 | 2578 | error ("mutable %qD is not usable in a constant expression", part); |
2579 | *non_constant_p = true; | |
2580 | } | |
2581 | if (*non_constant_p) | |
2582 | return t; | |
a4360e57 | 2583 | bool pmf = TYPE_PTRMEMFUNC_P (TREE_TYPE (whole)); |
09b42213 | 2584 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) |
2585 | { | |
a4360e57 | 2586 | /* Use name match for PMF fields, as a variant will have a |
2587 | different FIELD_DECL with a different type. */ | |
2588 | if (pmf ? DECL_NAME (field) == DECL_NAME (part) | |
2589 | : field == part) | |
9c96033c | 2590 | { |
2591 | if (value) | |
2592 | return value; | |
2593 | else | |
2594 | /* We're in the middle of initializing it. */ | |
2595 | break; | |
2596 | } | |
09b42213 | 2597 | } |
2598 | if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE | |
2599 | && CONSTRUCTOR_NELTS (whole) > 0) | |
2600 | { | |
2601 | /* DR 1188 says we don't have to deal with this. */ | |
f83e6885 | 2602 | if (!ctx->quiet) |
09b42213 | 2603 | error ("accessing %qD member instead of initialized %qD member in " |
2604 | "constant expression", part, CONSTRUCTOR_ELT (whole, 0)->index); | |
2605 | *non_constant_p = true; | |
2606 | return t; | |
2607 | } | |
2608 | ||
f894a056 | 2609 | /* We only create a CONSTRUCTOR for a subobject when we modify it, so empty |
2610 | classes never get represented; throw together a value now. */ | |
2611 | if (is_really_empty_class (TREE_TYPE (t))) | |
2612 | return build_constructor (TREE_TYPE (t), NULL); | |
2613 | ||
a4360e57 | 2614 | gcc_assert (DECL_CONTEXT (part) == TYPE_MAIN_VARIANT (TREE_TYPE (whole))); |
2615 | ||
165d0d5b | 2616 | if (CONSTRUCTOR_NO_CLEARING (whole)) |
cf72f34d | 2617 | { |
2618 | /* 'whole' is part of the aggregate initializer we're currently | |
2619 | building; if there's no initializer for this member yet, that's an | |
f894a056 | 2620 | error. */ |
f83e6885 | 2621 | if (!ctx->quiet) |
cf72f34d | 2622 | error ("accessing uninitialized member %qD", part); |
2623 | *non_constant_p = true; | |
2624 | return t; | |
2625 | } | |
2626 | ||
09b42213 | 2627 | /* If there's no explicit init for this field, it's value-initialized. */ |
2628 | value = build_value_init (TREE_TYPE (t), tf_warning_or_error); | |
cf72f34d | 2629 | return cxx_eval_constant_expression (ctx, value, |
1227ba74 | 2630 | lval, |
b2a43197 | 2631 | non_constant_p, overflow_p); |
09b42213 | 2632 | } |
2633 | ||
2634 | /* Subroutine of cxx_eval_constant_expression. | |
2635 | Attempt to reduce a field access of a value of class type that is | |
2636 | expressed as a BIT_FIELD_REF. */ | |
2637 | ||
2638 | static tree | |
cf72f34d | 2639 | cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2640 | bool lval, |
09b42213 | 2641 | bool *non_constant_p, bool *overflow_p) |
2642 | { | |
2643 | tree orig_whole = TREE_OPERAND (t, 0); | |
2644 | tree retval, fldval, utype, mask; | |
2645 | bool fld_seen = false; | |
2646 | HOST_WIDE_INT istart, isize; | |
cf72f34d | 2647 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2648 | lval, |
b2a43197 | 2649 | non_constant_p, overflow_p); |
09b42213 | 2650 | tree start, field, value; |
2651 | unsigned HOST_WIDE_INT i; | |
2652 | ||
2653 | if (whole == orig_whole) | |
2654 | return t; | |
2655 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2656 | CONSTRUCTOR. */ | |
2657 | if (!*non_constant_p | |
2658 | && TREE_CODE (whole) != VECTOR_CST | |
2659 | && TREE_CODE (whole) != CONSTRUCTOR) | |
2660 | { | |
f83e6885 | 2661 | if (!ctx->quiet) |
09b42213 | 2662 | error ("%qE is not a constant expression", orig_whole); |
2663 | *non_constant_p = true; | |
2664 | } | |
2665 | if (*non_constant_p) | |
2666 | return t; | |
2667 | ||
2668 | if (TREE_CODE (whole) == VECTOR_CST) | |
2669 | return fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole, | |
2670 | TREE_OPERAND (t, 1), TREE_OPERAND (t, 2)); | |
2671 | ||
2672 | start = TREE_OPERAND (t, 2); | |
2673 | istart = tree_to_shwi (start); | |
2674 | isize = tree_to_shwi (TREE_OPERAND (t, 1)); | |
2675 | utype = TREE_TYPE (t); | |
2676 | if (!TYPE_UNSIGNED (utype)) | |
2677 | utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1); | |
2678 | retval = build_int_cst (utype, 0); | |
2679 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
2680 | { | |
2681 | tree bitpos = bit_position (field); | |
2682 | if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1)) | |
2683 | return value; | |
2684 | if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE | |
2685 | && TREE_CODE (value) == INTEGER_CST | |
2686 | && tree_fits_shwi_p (bitpos) | |
2687 | && tree_fits_shwi_p (DECL_SIZE (field))) | |
2688 | { | |
2689 | HOST_WIDE_INT bit = tree_to_shwi (bitpos); | |
2690 | HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field)); | |
2691 | HOST_WIDE_INT shift; | |
2692 | if (bit >= istart && bit + sz <= istart + isize) | |
2693 | { | |
2694 | fldval = fold_convert (utype, value); | |
2695 | mask = build_int_cst_type (utype, -1); | |
2696 | mask = fold_build2 (LSHIFT_EXPR, utype, mask, | |
2697 | size_int (TYPE_PRECISION (utype) - sz)); | |
2698 | mask = fold_build2 (RSHIFT_EXPR, utype, mask, | |
2699 | size_int (TYPE_PRECISION (utype) - sz)); | |
2700 | fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask); | |
2701 | shift = bit - istart; | |
2702 | if (BYTES_BIG_ENDIAN) | |
2703 | shift = TYPE_PRECISION (utype) - shift - sz; | |
2704 | fldval = fold_build2 (LSHIFT_EXPR, utype, fldval, | |
2705 | size_int (shift)); | |
2706 | retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval); | |
2707 | fld_seen = true; | |
2708 | } | |
2709 | } | |
2710 | } | |
2711 | if (fld_seen) | |
2712 | return fold_convert (TREE_TYPE (t), retval); | |
2713 | gcc_unreachable (); | |
2714 | return error_mark_node; | |
2715 | } | |
2716 | ||
2717 | /* Subroutine of cxx_eval_constant_expression. | |
2718 | Evaluate a short-circuited logical expression T in the context | |
2719 | of a given constexpr CALL. BAILOUT_VALUE is the value for | |
2720 | early return. CONTINUE_VALUE is used here purely for | |
2721 | sanity check purposes. */ | |
2722 | ||
2723 | static tree | |
cf72f34d | 2724 | cxx_eval_logical_expression (const constexpr_ctx *ctx, tree t, |
09b42213 | 2725 | tree bailout_value, tree continue_value, |
1227ba74 | 2726 | bool lval, |
09b42213 | 2727 | bool *non_constant_p, bool *overflow_p) |
2728 | { | |
2729 | tree r; | |
cf72f34d | 2730 | tree lhs = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 2731 | lval, |
b2a43197 | 2732 | non_constant_p, overflow_p); |
09b42213 | 2733 | VERIFY_CONSTANT (lhs); |
2734 | if (tree_int_cst_equal (lhs, bailout_value)) | |
2735 | return lhs; | |
2736 | gcc_assert (tree_int_cst_equal (lhs, continue_value)); | |
cf72f34d | 2737 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2738 | lval, non_constant_p, |
b2a43197 | 2739 | overflow_p); |
09b42213 | 2740 | VERIFY_CONSTANT (r); |
2741 | return r; | |
2742 | } | |
2743 | ||
2744 | /* REF is a COMPONENT_REF designating a particular field. V is a vector of | |
2745 | CONSTRUCTOR elements to initialize (part of) an object containing that | |
2746 | field. Return a pointer to the constructor_elt corresponding to the | |
2747 | initialization of the field. */ | |
2748 | ||
2749 | static constructor_elt * | |
2750 | base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref) | |
2751 | { | |
2752 | tree aggr = TREE_OPERAND (ref, 0); | |
2753 | tree field = TREE_OPERAND (ref, 1); | |
2754 | HOST_WIDE_INT i; | |
2755 | constructor_elt *ce; | |
2756 | ||
2757 | gcc_assert (TREE_CODE (ref) == COMPONENT_REF); | |
2758 | ||
2759 | if (TREE_CODE (aggr) == COMPONENT_REF) | |
2760 | { | |
2761 | constructor_elt *base_ce | |
2762 | = base_field_constructor_elt (v, aggr); | |
2763 | v = CONSTRUCTOR_ELTS (base_ce->value); | |
2764 | } | |
2765 | ||
2766 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2767 | if (ce->index == field) | |
2768 | return ce; | |
2769 | ||
2770 | gcc_unreachable (); | |
2771 | return NULL; | |
2772 | } | |
2773 | ||
cf72f34d | 2774 | /* Some of the expressions fed to the constexpr mechanism are calls to |
2775 | constructors, which have type void. In that case, return the type being | |
2776 | initialized by the constructor. */ | |
2777 | ||
2778 | static tree | |
2779 | initialized_type (tree t) | |
2780 | { | |
2781 | if (TYPE_P (t)) | |
2782 | return t; | |
2783 | tree type = cv_unqualified (TREE_TYPE (t)); | |
2784 | if (TREE_CODE (t) == CALL_EXPR || TREE_CODE (t) == AGGR_INIT_EXPR) | |
2785 | { | |
2786 | /* A constructor call has void type, so we need to look deeper. */ | |
2787 | tree fn = get_function_named_in_call (t); | |
2788 | if (fn && TREE_CODE (fn) == FUNCTION_DECL | |
2789 | && DECL_CXX_CONSTRUCTOR_P (fn)) | |
2790 | type = DECL_CONTEXT (fn); | |
2791 | } | |
2792 | return type; | |
2793 | } | |
2794 | ||
2795 | /* We're about to initialize element INDEX of an array or class from VALUE. | |
2796 | Set up NEW_CTX appropriately by adjusting .object to refer to the | |
2797 | subobject and creating a new CONSTRUCTOR if the element is itself | |
2798 | a class or array. */ | |
2799 | ||
2800 | static void | |
2801 | init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, | |
2802 | tree index, tree &value) | |
2803 | { | |
2804 | new_ctx = *ctx; | |
2805 | ||
2806 | if (index && TREE_CODE (index) != INTEGER_CST | |
2807 | && TREE_CODE (index) != FIELD_DECL) | |
2808 | /* This won't have an element in the new CONSTRUCTOR. */ | |
2809 | return; | |
2810 | ||
2811 | tree type = initialized_type (value); | |
2812 | if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) | |
2813 | /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ | |
2814 | return; | |
2815 | ||
2816 | /* The sub-aggregate initializer might contain a placeholder; | |
2817 | update object to refer to the subobject and ctor to refer to | |
2818 | the (newly created) sub-initializer. */ | |
2819 | if (ctx->object) | |
2820 | new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); | |
2821 | tree elt = build_constructor (type, NULL); | |
165d0d5b | 2822 | CONSTRUCTOR_NO_CLEARING (elt) = true; |
cf72f34d | 2823 | new_ctx.ctor = elt; |
2824 | ||
2825 | if (TREE_CODE (value) == TARGET_EXPR) | |
2826 | /* Avoid creating another CONSTRUCTOR when we expand the TARGET_EXPR. */ | |
2827 | value = TARGET_EXPR_INITIAL (value); | |
2828 | } | |
2829 | ||
2830 | /* We're about to process an initializer for a class or array TYPE. Make | |
2831 | sure that CTX is set up appropriately. */ | |
2832 | ||
2833 | static void | |
2834 | verify_ctor_sanity (const constexpr_ctx *ctx, tree type) | |
2835 | { | |
2836 | /* We don't bother building a ctor for an empty base subobject. */ | |
2837 | if (is_empty_class (type)) | |
2838 | return; | |
2839 | ||
2840 | /* We're in the middle of an initializer that might involve placeholders; | |
2841 | our caller should have created a CONSTRUCTOR for us to put the | |
2842 | initializer into. We will either return that constructor or T. */ | |
2843 | gcc_assert (ctx->ctor); | |
2844 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2845 | (type, TREE_TYPE (ctx->ctor))); | |
bbf58224 | 2846 | /* We used to check that ctx->ctor was empty, but that isn't the case when |
2847 | the object is zero-initialized before calling the constructor. */ | |
cf72f34d | 2848 | if (ctx->object) |
d9751a3c | 2849 | { |
2850 | tree otype = TREE_TYPE (ctx->object); | |
2851 | gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, otype) | |
2852 | /* Handle flexible array members. */ | |
2853 | || (TREE_CODE (otype) == ARRAY_TYPE | |
2854 | && TYPE_DOMAIN (otype) == NULL_TREE | |
2855 | && TREE_CODE (type) == ARRAY_TYPE | |
2856 | && (same_type_ignoring_top_level_qualifiers_p | |
2857 | (TREE_TYPE (type), TREE_TYPE (otype))))); | |
2858 | } | |
cf72f34d | 2859 | gcc_assert (!ctx->object || !DECL_P (ctx->object) |
2860 | || *(ctx->values->get (ctx->object)) == ctx->ctor); | |
2861 | } | |
2862 | ||
09b42213 | 2863 | /* Subroutine of cxx_eval_constant_expression. |
2864 | The expression tree T denotes a C-style array or a C-style | |
2865 | aggregate. Reduce it to a constant expression. */ | |
2866 | ||
2867 | static tree | |
cf72f34d | 2868 | cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2869 | bool lval, |
09b42213 | 2870 | bool *non_constant_p, bool *overflow_p) |
2871 | { | |
2872 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
09b42213 | 2873 | bool changed = false; |
2874 | gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t)); | |
68464393 | 2875 | tree type = TREE_TYPE (t); |
cf72f34d | 2876 | |
68464393 | 2877 | constexpr_ctx new_ctx; |
d2dd85e3 | 2878 | if (TYPE_PTRMEMFUNC_P (type) || VECTOR_TYPE_P (type)) |
68464393 | 2879 | { |
d2dd85e3 | 2880 | /* We don't really need the ctx->ctor business for a PMF or |
2881 | vector, but it's simpler to use the same code. */ | |
68464393 | 2882 | new_ctx = *ctx; |
2883 | new_ctx.ctor = build_constructor (type, NULL); | |
2884 | new_ctx.object = NULL_TREE; | |
2885 | ctx = &new_ctx; | |
2886 | }; | |
2887 | verify_ctor_sanity (ctx, type); | |
cf72f34d | 2888 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); |
2889 | vec_alloc (*p, vec_safe_length (v)); | |
2890 | ||
58b0f9ce | 2891 | unsigned i; |
2892 | tree index, value; | |
2893 | bool constant_p = true; | |
2894 | bool side_effects_p = false; | |
cf72f34d | 2895 | FOR_EACH_CONSTRUCTOR_ELT (v, i, index, value) |
09b42213 | 2896 | { |
5ae773e4 | 2897 | tree orig_value = value; |
cf72f34d | 2898 | init_subob_ctx (ctx, new_ctx, index, value); |
2899 | if (new_ctx.ctor != ctx->ctor) | |
2900 | /* If we built a new CONSTRUCTOR, attach it now so that other | |
2901 | initializers can refer to it. */ | |
2902 | CONSTRUCTOR_APPEND_ELT (*p, index, new_ctx.ctor); | |
2903 | tree elt = cxx_eval_constant_expression (&new_ctx, value, | |
1227ba74 | 2904 | lval, |
b2a43197 | 2905 | non_constant_p, overflow_p); |
09b42213 | 2906 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 2907 | if (ctx->quiet && *non_constant_p) |
cf72f34d | 2908 | break; |
5ae773e4 | 2909 | if (elt != orig_value) |
09b42213 | 2910 | changed = true; |
58b0f9ce | 2911 | |
2912 | if (!TREE_CONSTANT (elt)) | |
2913 | constant_p = false; | |
2914 | if (TREE_SIDE_EFFECTS (elt)) | |
2915 | side_effects_p = true; | |
cf72f34d | 2916 | if (index && TREE_CODE (index) == COMPONENT_REF) |
09b42213 | 2917 | { |
2918 | /* This is an initialization of a vfield inside a base | |
2919 | subaggregate that we already initialized; push this | |
2920 | initialization into the previous initialization. */ | |
cf72f34d | 2921 | constructor_elt *inner = base_field_constructor_elt (*p, index); |
09b42213 | 2922 | inner->value = elt; |
cf72f34d | 2923 | changed = true; |
09b42213 | 2924 | } |
cf72f34d | 2925 | else if (index |
2926 | && (TREE_CODE (index) == NOP_EXPR | |
2927 | || TREE_CODE (index) == POINTER_PLUS_EXPR)) | |
09b42213 | 2928 | { |
2929 | /* This is an initializer for an empty base; now that we've | |
2930 | checked that it's constant, we can ignore it. */ | |
cf72f34d | 2931 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (index)))); |
2932 | changed = true; | |
2933 | } | |
09b42213 | 2934 | else |
79e65a6b | 2935 | { |
0dd49b5a | 2936 | if (new_ctx.ctor != ctx->ctor) |
2937 | { | |
2938 | /* We appended this element above; update the value. */ | |
2939 | gcc_assert ((*p)->last().index == index); | |
2940 | (*p)->last().value = elt; | |
2941 | } | |
2942 | else | |
2943 | CONSTRUCTOR_APPEND_ELT (*p, index, elt); | |
2944 | /* Adding or replacing an element might change the ctor's flags. */ | |
79e65a6b | 2945 | TREE_CONSTANT (ctx->ctor) = constant_p; |
2946 | TREE_SIDE_EFFECTS (ctx->ctor) = side_effects_p; | |
2947 | } | |
09b42213 | 2948 | } |
2949 | if (*non_constant_p || !changed) | |
cf72f34d | 2950 | return t; |
2951 | t = ctx->ctor; | |
2952 | /* We're done building this CONSTRUCTOR, so now we can interpret an | |
2953 | element without an explicit initializer as value-initialized. */ | |
165d0d5b | 2954 | CONSTRUCTOR_NO_CLEARING (t) = false; |
58b0f9ce | 2955 | TREE_CONSTANT (t) = constant_p; |
2956 | TREE_SIDE_EFFECTS (t) = side_effects_p; | |
68464393 | 2957 | if (VECTOR_TYPE_P (type)) |
09b42213 | 2958 | t = fold (t); |
2959 | return t; | |
2960 | } | |
2961 | ||
2962 | /* Subroutine of cxx_eval_constant_expression. | |
2963 | The expression tree T is a VEC_INIT_EXPR which denotes the desired | |
2964 | initialization of a non-static data member of array type. Reduce it to a | |
2965 | CONSTRUCTOR. | |
2966 | ||
2967 | Note that apart from value-initialization (when VALUE_INIT is true), | |
2968 | this is only intended to support value-initialization and the | |
2969 | initializations done by defaulted constructors for classes with | |
2970 | non-static data members of array type. In this case, VEC_INIT_EXPR_INIT | |
2971 | will either be NULL_TREE for the default constructor, or a COMPONENT_REF | |
2972 | for the copy/move constructor. */ | |
2973 | ||
2974 | static tree | |
cf72f34d | 2975 | cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, |
1227ba74 | 2976 | bool value_init, bool lval, |
09b42213 | 2977 | bool *non_constant_p, bool *overflow_p) |
2978 | { | |
2979 | tree elttype = TREE_TYPE (atype); | |
cf72f34d | 2980 | verify_ctor_sanity (ctx, atype); |
2981 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
09b42213 | 2982 | bool pre_init = false; |
3e520b97 | 2983 | unsigned HOST_WIDE_INT i; |
c4970310 | 2984 | tsubst_flags_t complain = ctx->quiet ? tf_none : tf_warning_or_error; |
09b42213 | 2985 | |
2986 | /* For the default constructor, build up a call to the default | |
2987 | constructor of the element type. We only need to handle class types | |
2988 | here, as for a constructor to be constexpr, all members must be | |
2989 | initialized, which for a defaulted default constructor means they must | |
2990 | be of a class type with a constexpr default constructor. */ | |
2991 | if (TREE_CODE (elttype) == ARRAY_TYPE) | |
2992 | /* We only do this at the lowest level. */; | |
2993 | else if (value_init) | |
2994 | { | |
c4970310 | 2995 | init = build_value_init (elttype, complain); |
09b42213 | 2996 | pre_init = true; |
2997 | } | |
2998 | else if (!init) | |
2999 | { | |
3000 | vec<tree, va_gc> *argvec = make_tree_vector (); | |
3001 | init = build_special_member_call (NULL_TREE, complete_ctor_identifier, | |
3002 | &argvec, elttype, LOOKUP_NORMAL, | |
c4970310 | 3003 | complain); |
09b42213 | 3004 | release_tree_vector (argvec); |
9c96033c | 3005 | init = build_aggr_init_expr (TREE_TYPE (init), init); |
09b42213 | 3006 | pre_init = true; |
3007 | } | |
3008 | ||
51f0c7e2 | 3009 | tree nelts = get_array_or_vector_nelts (ctx, atype, non_constant_p, |
3010 | overflow_p); | |
3011 | unsigned HOST_WIDE_INT max = tree_to_uhwi (nelts); | |
3e520b97 | 3012 | for (i = 0; i < max; ++i) |
09b42213 | 3013 | { |
3014 | tree idx = build_int_cst (size_type_node, i); | |
3015 | tree eltinit; | |
d9377ad5 | 3016 | bool reuse = false; |
cf72f34d | 3017 | constexpr_ctx new_ctx; |
3018 | init_subob_ctx (ctx, new_ctx, idx, pre_init ? init : elttype); | |
3019 | if (new_ctx.ctor != ctx->ctor) | |
3020 | CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor); | |
09b42213 | 3021 | if (TREE_CODE (elttype) == ARRAY_TYPE) |
3022 | { | |
3023 | /* A multidimensional array; recurse. */ | |
3024 | if (value_init || init == NULL_TREE) | |
d9377ad5 | 3025 | { |
3026 | eltinit = NULL_TREE; | |
3027 | reuse = i == 0; | |
3028 | } | |
09b42213 | 3029 | else |
c4970310 | 3030 | eltinit = cp_build_array_ref (input_location, init, idx, complain); |
cf72f34d | 3031 | eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, value_init, |
1227ba74 | 3032 | lval, |
09b42213 | 3033 | non_constant_p, overflow_p); |
3034 | } | |
3035 | else if (pre_init) | |
3036 | { | |
3037 | /* Initializing an element using value or default initialization | |
3038 | we just pre-built above. */ | |
d9377ad5 | 3039 | eltinit = cxx_eval_constant_expression (&new_ctx, init, lval, |
3040 | non_constant_p, overflow_p); | |
3041 | reuse = i == 0; | |
09b42213 | 3042 | } |
3043 | else | |
3044 | { | |
3045 | /* Copying an element. */ | |
3046 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
3047 | (atype, TREE_TYPE (init))); | |
c4970310 | 3048 | eltinit = cp_build_array_ref (input_location, init, idx, complain); |
18bede74 | 3049 | if (!lvalue_p (init)) |
09b42213 | 3050 | eltinit = move (eltinit); |
c4970310 | 3051 | eltinit = force_rvalue (eltinit, complain); |
eb7c25cc | 3052 | eltinit = cxx_eval_constant_expression (&new_ctx, eltinit, lval, |
3053 | non_constant_p, overflow_p); | |
09b42213 | 3054 | } |
f83e6885 | 3055 | if (*non_constant_p && !ctx->quiet) |
cf72f34d | 3056 | break; |
3057 | if (new_ctx.ctor != ctx->ctor) | |
3058 | { | |
3059 | /* We appended this element above; update the value. */ | |
3060 | gcc_assert ((*p)->last().index == idx); | |
3061 | (*p)->last().value = eltinit; | |
3062 | } | |
3063 | else | |
3064 | CONSTRUCTOR_APPEND_ELT (*p, idx, eltinit); | |
d9377ad5 | 3065 | /* Reuse the result of cxx_eval_constant_expression call |
eb7c25cc | 3066 | from the first iteration to all others if it is a constant |
3067 | initializer that doesn't require relocations. */ | |
d9377ad5 | 3068 | if (reuse |
3069 | && max > 1 | |
eb7c25cc | 3070 | && (eltinit == NULL_TREE |
3071 | || (initializer_constant_valid_p (eltinit, TREE_TYPE (eltinit)) | |
3072 | == null_pointer_node))) | |
d9377ad5 | 3073 | { |
3074 | if (new_ctx.ctor != ctx->ctor) | |
3075 | eltinit = new_ctx.ctor; | |
228a2cd8 | 3076 | tree range = build2 (RANGE_EXPR, size_type_node, |
3077 | build_int_cst (size_type_node, 1), | |
3078 | build_int_cst (size_type_node, max - 1)); | |
3079 | CONSTRUCTOR_APPEND_ELT (*p, range, unshare_constructor (eltinit)); | |
d9377ad5 | 3080 | break; |
3081 | } | |
228a2cd8 | 3082 | else if (i == 0) |
3083 | vec_safe_reserve (*p, max); | |
09b42213 | 3084 | } |
3085 | ||
3086 | if (!*non_constant_p) | |
3087 | { | |
cf72f34d | 3088 | init = ctx->ctor; |
165d0d5b | 3089 | CONSTRUCTOR_NO_CLEARING (init) = false; |
09b42213 | 3090 | } |
09b42213 | 3091 | return init; |
3092 | } | |
3093 | ||
3094 | static tree | |
cf72f34d | 3095 | cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3096 | bool lval, |
09b42213 | 3097 | bool *non_constant_p, bool *overflow_p) |
3098 | { | |
3099 | tree atype = TREE_TYPE (t); | |
3100 | tree init = VEC_INIT_EXPR_INIT (t); | |
cf72f34d | 3101 | tree r = cxx_eval_vec_init_1 (ctx, atype, init, |
09b42213 | 3102 | VEC_INIT_EXPR_VALUE_INIT (t), |
1227ba74 | 3103 | lval, non_constant_p, overflow_p); |
09b42213 | 3104 | if (*non_constant_p) |
3105 | return t; | |
3106 | else | |
3107 | return r; | |
3108 | } | |
3109 | ||
6b53d686 | 3110 | /* Like same_type_ignoring_top_level_qualifiers_p, but also handle the case |
3111 | where the desired type is an array of unknown bounds because the variable | |
3112 | has had its bounds deduced since the wrapping expression was created. */ | |
3113 | ||
3114 | static bool | |
3115 | same_type_ignoring_tlq_and_bounds_p (tree type1, tree type2) | |
3116 | { | |
3117 | while (TREE_CODE (type1) == ARRAY_TYPE | |
3118 | && TREE_CODE (type2) == ARRAY_TYPE | |
3119 | && (!TYPE_DOMAIN (type1) || !TYPE_DOMAIN (type2))) | |
3120 | { | |
3121 | type1 = TREE_TYPE (type1); | |
3122 | type2 = TREE_TYPE (type2); | |
3123 | } | |
3124 | return same_type_ignoring_top_level_qualifiers_p (type1, type2); | |
3125 | } | |
3126 | ||
09b42213 | 3127 | /* A less strict version of fold_indirect_ref_1, which requires cv-quals to |
3128 | match. We want to be less strict for simple *& folding; if we have a | |
3129 | non-const temporary that we access through a const pointer, that should | |
3130 | work. We handle this here rather than change fold_indirect_ref_1 | |
3131 | because we're dealing with things like ADDR_EXPR of INTEGER_CST which | |
3132 | don't really make sense outside of constant expression evaluation. Also | |
3133 | we want to allow folding to COMPONENT_REF, which could cause trouble | |
3134 | with TBAA in fold_indirect_ref_1. | |
3135 | ||
3136 | Try to keep this function synced with fold_indirect_ref_1. */ | |
3137 | ||
3138 | static tree | |
3139 | cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) | |
3140 | { | |
7d8e655d | 3141 | tree sub = op0; |
3142 | tree subtype; | |
3143 | poly_uint64 const_op01; | |
09b42213 | 3144 | |
09b42213 | 3145 | STRIP_NOPS (sub); |
3146 | subtype = TREE_TYPE (sub); | |
d03fa520 | 3147 | if (!INDIRECT_TYPE_P (subtype)) |
09b42213 | 3148 | return NULL_TREE; |
3149 | ||
3150 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3151 | { | |
3152 | tree op = TREE_OPERAND (sub, 0); | |
3153 | tree optype = TREE_TYPE (op); | |
3154 | ||
3155 | /* *&CONST_DECL -> to the value of the const decl. */ | |
3156 | if (TREE_CODE (op) == CONST_DECL) | |
3157 | return DECL_INITIAL (op); | |
3158 | /* *&p => p; make sure to handle *&"str"[cst] here. */ | |
6b53d686 | 3159 | if (same_type_ignoring_tlq_and_bounds_p (optype, type)) |
09b42213 | 3160 | { |
3161 | tree fop = fold_read_from_constant_string (op); | |
3162 | if (fop) | |
3163 | return fop; | |
3164 | else | |
3165 | return op; | |
3166 | } | |
3167 | /* *(foo *)&fooarray => fooarray[0] */ | |
3168 | else if (TREE_CODE (optype) == ARRAY_TYPE | |
3169 | && (same_type_ignoring_top_level_qualifiers_p | |
3170 | (type, TREE_TYPE (optype)))) | |
3171 | { | |
3172 | tree type_domain = TYPE_DOMAIN (optype); | |
3173 | tree min_val = size_zero_node; | |
3174 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3175 | min_val = TYPE_MIN_VALUE (type_domain); | |
3176 | return build4_loc (loc, ARRAY_REF, type, op, min_val, | |
3177 | NULL_TREE, NULL_TREE); | |
3178 | } | |
3179 | /* *(foo *)&complexfoo => __real__ complexfoo */ | |
3180 | else if (TREE_CODE (optype) == COMPLEX_TYPE | |
3181 | && (same_type_ignoring_top_level_qualifiers_p | |
3182 | (type, TREE_TYPE (optype)))) | |
3183 | return fold_build1_loc (loc, REALPART_EXPR, type, op); | |
3184 | /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3185 | else if (VECTOR_TYPE_P (optype) |
09b42213 | 3186 | && (same_type_ignoring_top_level_qualifiers_p |
3187 | (type, TREE_TYPE (optype)))) | |
3188 | { | |
3189 | tree part_width = TYPE_SIZE (type); | |
3190 | tree index = bitsize_int (0); | |
7d8e655d | 3191 | return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, |
3192 | index); | |
09b42213 | 3193 | } |
3194 | /* Also handle conversion to an empty base class, which | |
3195 | is represented with a NOP_EXPR. */ | |
3196 | else if (is_empty_class (type) | |
3197 | && CLASS_TYPE_P (optype) | |
3198 | && DERIVED_FROM_P (type, optype)) | |
3199 | { | |
3200 | *empty_base = true; | |
3201 | return op; | |
3202 | } | |
3203 | /* *(foo *)&struct_with_foo_field => COMPONENT_REF */ | |
3204 | else if (RECORD_OR_UNION_TYPE_P (optype)) | |
3205 | { | |
3206 | tree field = TYPE_FIELDS (optype); | |
3207 | for (; field; field = DECL_CHAIN (field)) | |
3208 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3209 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3210 | && integer_zerop (byte_position (field)) |
3211 | && (same_type_ignoring_top_level_qualifiers_p | |
3212 | (TREE_TYPE (field), type))) | |
a48667ee | 3213 | return fold_build3 (COMPONENT_REF, type, op, field, NULL_TREE); |
09b42213 | 3214 | } |
3215 | } | |
3216 | else if (TREE_CODE (sub) == POINTER_PLUS_EXPR | |
7d8e655d | 3217 | && poly_int_tree_p (TREE_OPERAND (sub, 1), &const_op01)) |
09b42213 | 3218 | { |
3219 | tree op00 = TREE_OPERAND (sub, 0); | |
3220 | tree op01 = TREE_OPERAND (sub, 1); | |
3221 | ||
3222 | STRIP_NOPS (op00); | |
3223 | if (TREE_CODE (op00) == ADDR_EXPR) | |
3224 | { | |
3225 | tree op00type; | |
3226 | op00 = TREE_OPERAND (op00, 0); | |
3227 | op00type = TREE_TYPE (op00); | |
3228 | ||
3229 | /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3230 | if (VECTOR_TYPE_P (op00type) |
7d8e655d | 3231 | && same_type_ignoring_top_level_qualifiers_p |
3232 | (type, TREE_TYPE (op00type)) | |
3233 | /* POINTER_PLUS_EXPR second operand is sizetype, unsigned, | |
3234 | but we want to treat offsets with MSB set as negative. | |
3235 | For the code below negative offsets are invalid and | |
3236 | TYPE_SIZE of the element is something unsigned, so | |
3237 | check whether op01 fits into poly_int64, which implies | |
3238 | it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and | |
3239 | then just use poly_uint64 because we want to treat the | |
3240 | value as unsigned. */ | |
3241 | && tree_fits_poly_int64_p (op01)) | |
09b42213 | 3242 | { |
09b42213 | 3243 | tree part_width = TYPE_SIZE (type); |
7d8e655d | 3244 | poly_uint64 max_offset |
3245 | = (tree_to_uhwi (part_width) / BITS_PER_UNIT | |
3246 | * TYPE_VECTOR_SUBPARTS (op00type)); | |
3247 | if (known_lt (const_op01, max_offset)) | |
3248 | { | |
3249 | tree index = bitsize_int (const_op01 * BITS_PER_UNIT); | |
3250 | return fold_build3_loc (loc, | |
3251 | BIT_FIELD_REF, type, op00, | |
3252 | part_width, index); | |
3253 | } | |
09b42213 | 3254 | } |
3255 | /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ | |
3256 | else if (TREE_CODE (op00type) == COMPLEX_TYPE | |
3257 | && (same_type_ignoring_top_level_qualifiers_p | |
3258 | (type, TREE_TYPE (op00type)))) | |
3259 | { | |
7d8e655d | 3260 | if (known_eq (wi::to_poly_offset (TYPE_SIZE_UNIT (type)), |
3261 | const_op01)) | |
09b42213 | 3262 | return fold_build1_loc (loc, IMAGPART_EXPR, type, op00); |
3263 | } | |
3264 | /* ((foo *)&fooarray)[1] => fooarray[1] */ | |
3265 | else if (TREE_CODE (op00type) == ARRAY_TYPE | |
3266 | && (same_type_ignoring_top_level_qualifiers_p | |
3267 | (type, TREE_TYPE (op00type)))) | |
3268 | { | |
3269 | tree type_domain = TYPE_DOMAIN (op00type); | |
3270 | tree min_val = size_zero_node; | |
3271 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3272 | min_val = TYPE_MIN_VALUE (type_domain); | |
53fa96c0 | 3273 | offset_int off = wi::to_offset (op01); |
3274 | offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type)); | |
3275 | offset_int remainder; | |
3276 | off = wi::divmod_trunc (off, el_sz, SIGNED, &remainder); | |
3277 | if (remainder == 0 && TREE_CODE (min_val) == INTEGER_CST) | |
3278 | { | |
3279 | off = off + wi::to_offset (min_val); | |
3280 | op01 = wide_int_to_tree (sizetype, off); | |
3281 | return build4_loc (loc, ARRAY_REF, type, op00, op01, | |
3282 | NULL_TREE, NULL_TREE); | |
3283 | } | |
09b42213 | 3284 | } |
3285 | /* Also handle conversion to an empty base class, which | |
3286 | is represented with a NOP_EXPR. */ | |
3287 | else if (is_empty_class (type) | |
3288 | && CLASS_TYPE_P (op00type) | |
3289 | && DERIVED_FROM_P (type, op00type)) | |
3290 | { | |
3291 | *empty_base = true; | |
3292 | return op00; | |
3293 | } | |
3294 | /* ((foo *)&struct_with_foo_field)[1] => COMPONENT_REF */ | |
3295 | else if (RECORD_OR_UNION_TYPE_P (op00type)) | |
3296 | { | |
3297 | tree field = TYPE_FIELDS (op00type); | |
3298 | for (; field; field = DECL_CHAIN (field)) | |
3299 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3300 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3301 | && tree_int_cst_equal (byte_position (field), op01) |
3302 | && (same_type_ignoring_top_level_qualifiers_p | |
3303 | (TREE_TYPE (field), type))) | |
a48667ee | 3304 | return fold_build3 (COMPONENT_REF, type, op00, |
3305 | field, NULL_TREE); | |
09b42213 | 3306 | } |
3307 | } | |
3308 | } | |
3309 | /* *(foo *)fooarrptr => (*fooarrptr)[0] */ | |
3310 | else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE | |
3311 | && (same_type_ignoring_top_level_qualifiers_p | |
3312 | (type, TREE_TYPE (TREE_TYPE (subtype))))) | |
3313 | { | |
3314 | tree type_domain; | |
3315 | tree min_val = size_zero_node; | |
7d8e655d | 3316 | tree newsub |
3317 | = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL); | |
09b42213 | 3318 | if (newsub) |
3319 | sub = newsub; | |
3320 | else | |
3321 | sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub); | |
3322 | type_domain = TYPE_DOMAIN (TREE_TYPE (sub)); | |
3323 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3324 | min_val = TYPE_MIN_VALUE (type_domain); | |
3325 | return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE, | |
3326 | NULL_TREE); | |
3327 | } | |
3328 | ||
3329 | return NULL_TREE; | |
3330 | } | |
3331 | ||
3332 | static tree | |
cf72f34d | 3333 | cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3334 | bool lval, |
09b42213 | 3335 | bool *non_constant_p, bool *overflow_p) |
3336 | { | |
3337 | tree orig_op0 = TREE_OPERAND (t, 0); | |
09b42213 | 3338 | bool empty_base = false; |
09b42213 | 3339 | |
d2c63826 | 3340 | /* We can handle a MEM_REF like an INDIRECT_REF, if MEM_REF's second |
3341 | operand is an integer-zero. Otherwise reject the MEM_REF for now. */ | |
3342 | ||
3343 | if (TREE_CODE (t) == MEM_REF | |
3344 | && (!TREE_OPERAND (t, 1) || !integer_zerop (TREE_OPERAND (t, 1)))) | |
3345 | { | |
3346 | gcc_assert (ctx->quiet); | |
3347 | *non_constant_p = true; | |
3348 | return t; | |
3349 | } | |
3350 | ||
7e0f3388 | 3351 | /* First try to simplify it directly. */ |
3352 | tree r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), orig_op0, | |
3353 | &empty_base); | |
3354 | if (!r) | |
09b42213 | 3355 | { |
7e0f3388 | 3356 | /* If that didn't work, evaluate the operand first. */ |
3357 | tree op0 = cxx_eval_constant_expression (ctx, orig_op0, | |
3358 | /*lval*/false, non_constant_p, | |
3359 | overflow_p); | |
3360 | /* Don't VERIFY_CONSTANT here. */ | |
3361 | if (*non_constant_p) | |
3362 | return t; | |
3363 | ||
cb768824 | 3364 | if (!lval && integer_zerop (op0)) |
3365 | { | |
3366 | if (!ctx->quiet) | |
3367 | error ("dereferencing a null pointer"); | |
3368 | *non_constant_p = true; | |
3369 | return t; | |
3370 | } | |
3371 | ||
7e0f3388 | 3372 | r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), op0, |
3373 | &empty_base); | |
3374 | if (r == NULL_TREE) | |
09b42213 | 3375 | { |
3376 | /* We couldn't fold to a constant value. Make sure it's not | |
3377 | something we should have been able to fold. */ | |
7e0f3388 | 3378 | tree sub = op0; |
3379 | STRIP_NOPS (sub); | |
3380 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3381 | { | |
3382 | gcc_assert (!same_type_ignoring_top_level_qualifiers_p | |
3383 | (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t))); | |
3384 | /* DR 1188 says we don't have to deal with this. */ | |
3385 | if (!ctx->quiet) | |
3386 | error ("accessing value of %qE through a %qT glvalue in a " | |
3387 | "constant expression", build_fold_indirect_ref (sub), | |
3388 | TREE_TYPE (t)); | |
3389 | *non_constant_p = true; | |
3390 | return t; | |
3391 | } | |
3392 | ||
3393 | if (lval && op0 != orig_op0) | |
3394 | return build1 (INDIRECT_REF, TREE_TYPE (t), op0); | |
3395 | if (!lval) | |
3396 | VERIFY_CONSTANT (t); | |
09b42213 | 3397 | return t; |
3398 | } | |
3399 | } | |
3400 | ||
7e0f3388 | 3401 | r = cxx_eval_constant_expression (ctx, r, |
3402 | lval, non_constant_p, overflow_p); | |
3403 | if (*non_constant_p) | |
3404 | return t; | |
3405 | ||
ce4ffd9e | 3406 | /* If we're pulling out the value of an empty base, just return an empty |
09b42213 | 3407 | CONSTRUCTOR. */ |
1227ba74 | 3408 | if (empty_base && !lval) |
09b42213 | 3409 | { |
09b42213 | 3410 | r = build_constructor (TREE_TYPE (t), NULL); |
3411 | TREE_CONSTANT (r) = true; | |
3412 | } | |
3413 | ||
09b42213 | 3414 | return r; |
3415 | } | |
3416 | ||
3417 | /* Complain about R, a VAR_DECL, not being usable in a constant expression. | |
3418 | Shared between potential_constant_expression and | |
3419 | cxx_eval_constant_expression. */ | |
3420 | ||
3421 | static void | |
3422 | non_const_var_error (tree r) | |
3423 | { | |
3424 | tree type = TREE_TYPE (r); | |
3425 | error ("the value of %qD is not usable in a constant " | |
3426 | "expression", r); | |
3427 | /* Avoid error cascade. */ | |
3428 | if (DECL_INITIAL (r) == error_mark_node) | |
3429 | return; | |
3430 | if (DECL_DECLARED_CONSTEXPR_P (r)) | |
3431 | inform (DECL_SOURCE_LOCATION (r), | |
3432 | "%qD used in its own initializer", r); | |
3433 | else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) | |
3434 | { | |
3435 | if (!CP_TYPE_CONST_P (type)) | |
3436 | inform (DECL_SOURCE_LOCATION (r), | |
3437 | "%q#D is not const", r); | |
3438 | else if (CP_TYPE_VOLATILE_P (type)) | |
3439 | inform (DECL_SOURCE_LOCATION (r), | |
3440 | "%q#D is volatile", r); | |
3441 | else if (!DECL_INITIAL (r) | |
c8e3e744 | 3442 | || !TREE_CONSTANT (DECL_INITIAL (r)) |
3443 | || !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (r)) | |
09b42213 | 3444 | inform (DECL_SOURCE_LOCATION (r), |
3445 | "%qD was not initialized with a constant " | |
3446 | "expression", r); | |
3447 | else | |
3448 | gcc_unreachable (); | |
3449 | } | |
90ad495b | 3450 | else if (TYPE_REF_P (type)) |
ac6641ca | 3451 | inform (DECL_SOURCE_LOCATION (r), |
3452 | "%qD was not initialized with a constant " | |
3453 | "expression", r); | |
09b42213 | 3454 | else |
3455 | { | |
3456 | if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r)) | |
3457 | inform (DECL_SOURCE_LOCATION (r), | |
3458 | "%qD was not declared %<constexpr%>", r); | |
3459 | else | |
3460 | inform (DECL_SOURCE_LOCATION (r), | |
3461 | "%qD does not have integral or enumeration type", | |
3462 | r); | |
3463 | } | |
3464 | } | |
3465 | ||
3466 | /* Subroutine of cxx_eval_constant_expression. | |
3467 | Like cxx_eval_unary_expression, except for trinary expressions. */ | |
3468 | ||
3469 | static tree | |
cf72f34d | 3470 | cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3471 | bool lval, |
09b42213 | 3472 | bool *non_constant_p, bool *overflow_p) |
3473 | { | |
3474 | int i; | |
3475 | tree args[3]; | |
3476 | tree val; | |
3477 | ||
3478 | for (i = 0; i < 3; i++) | |
3479 | { | |
cf72f34d | 3480 | args[i] = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, i), |
1227ba74 | 3481 | lval, |
b2a43197 | 3482 | non_constant_p, overflow_p); |
09b42213 | 3483 | VERIFY_CONSTANT (args[i]); |
3484 | } | |
3485 | ||
3486 | val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t), | |
3487 | args[0], args[1], args[2]); | |
3488 | if (val == NULL_TREE) | |
3489 | return t; | |
3490 | VERIFY_CONSTANT (val); | |
3491 | return val; | |
3492 | } | |
3493 | ||
33603066 | 3494 | /* True if T was declared in a function declared to be constexpr, and |
3495 | therefore potentially constant in C++14. */ | |
3496 | ||
09b42213 | 3497 | bool |
3498 | var_in_constexpr_fn (tree t) | |
3499 | { | |
3500 | tree ctx = DECL_CONTEXT (t); | |
33603066 | 3501 | return (ctx && TREE_CODE (ctx) == FUNCTION_DECL |
09b42213 | 3502 | && DECL_DECLARED_CONSTEXPR_P (ctx)); |
3503 | } | |
3504 | ||
33603066 | 3505 | /* True if T was declared in a function that might be constexpr: either a |
3506 | function that was declared constexpr, or a C++17 lambda op(). */ | |
3507 | ||
3508 | bool | |
3509 | var_in_maybe_constexpr_fn (tree t) | |
3510 | { | |
40e2decb | 3511 | if (cxx_dialect >= cxx17 |
33603066 | 3512 | && DECL_FUNCTION_SCOPE_P (t) |
3513 | && LAMBDA_FUNCTION_P (DECL_CONTEXT (t))) | |
3514 | return true; | |
3515 | return var_in_constexpr_fn (t); | |
3516 | } | |
3517 | ||
93312944 | 3518 | /* We're assigning INIT to TARGET. In do_build_copy_constructor and |
3519 | build_over_call we implement trivial copy of a class with tail padding using | |
3520 | assignment of character arrays, which is valid in normal code, but not in | |
3521 | constexpr evaluation. We don't need to worry about clobbering tail padding | |
3522 | in constexpr evaluation, so strip the type punning. */ | |
3523 | ||
3524 | static void | |
3525 | maybe_simplify_trivial_copy (tree &target, tree &init) | |
3526 | { | |
3527 | if (TREE_CODE (target) == MEM_REF | |
3528 | && TREE_CODE (init) == MEM_REF | |
3529 | && TREE_TYPE (target) == TREE_TYPE (init) | |
3530 | && TREE_CODE (TREE_TYPE (target)) == ARRAY_TYPE | |
3531 | && TREE_TYPE (TREE_TYPE (target)) == unsigned_char_type_node) | |
3532 | { | |
3533 | target = build_fold_indirect_ref (TREE_OPERAND (target, 0)); | |
3534 | init = build_fold_indirect_ref (TREE_OPERAND (init, 0)); | |
3535 | } | |
3536 | } | |
3537 | ||
9c96033c | 3538 | /* Evaluate an INIT_EXPR or MODIFY_EXPR. */ |
3539 | ||
3540 | static tree | |
3541 | cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3542 | bool lval, |
9c96033c | 3543 | bool *non_constant_p, bool *overflow_p) |
3544 | { | |
3545 | constexpr_ctx new_ctx = *ctx; | |
3546 | ||
8a36d0ec | 3547 | tree init = TREE_OPERAND (t, 1); |
3548 | if (TREE_CLOBBER_P (init)) | |
3549 | /* Just ignore clobbers. */ | |
3550 | return void_node; | |
3551 | ||
9c96033c | 3552 | /* First we figure out where we're storing to. */ |
3553 | tree target = TREE_OPERAND (t, 0); | |
93312944 | 3554 | |
3555 | maybe_simplify_trivial_copy (target, init); | |
3556 | ||
9db9fc38 | 3557 | tree type = TREE_TYPE (target); |
9c96033c | 3558 | target = cxx_eval_constant_expression (ctx, target, |
f83e6885 | 3559 | true, |
b2a43197 | 3560 | non_constant_p, overflow_p); |
9c96033c | 3561 | if (*non_constant_p) |
3562 | return t; | |
3563 | ||
cf3cefc9 | 3564 | /* cxx_eval_array_reference for lval = true allows references one past |
3565 | end of array, because it does not know if it is just taking address | |
3566 | (which is valid), or actual dereference. Here we know it is | |
3567 | a dereference, so diagnose it here. */ | |
3568 | for (tree probe = target; probe; ) | |
3569 | { | |
3570 | switch (TREE_CODE (probe)) | |
3571 | { | |
3572 | case ARRAY_REF: | |
3573 | tree nelts, ary; | |
3574 | ary = TREE_OPERAND (probe, 0); | |
51f0c7e2 | 3575 | nelts = get_array_or_vector_nelts (ctx, TREE_TYPE (ary), |
3576 | non_constant_p, overflow_p); | |
cf3cefc9 | 3577 | VERIFY_CONSTANT (nelts); |
3578 | gcc_assert (TREE_CODE (nelts) == INTEGER_CST | |
3579 | && TREE_CODE (TREE_OPERAND (probe, 1)) == INTEGER_CST); | |
cb7bca5f | 3580 | if (wi::to_widest (TREE_OPERAND (probe, 1)) == wi::to_widest (nelts)) |
cf3cefc9 | 3581 | { |
3582 | diag_array_subscript (ctx, ary, TREE_OPERAND (probe, 1)); | |
3583 | *non_constant_p = true; | |
3584 | return t; | |
3585 | } | |
3586 | /* FALLTHRU */ | |
3587 | ||
3588 | case BIT_FIELD_REF: | |
3589 | case COMPONENT_REF: | |
3590 | probe = TREE_OPERAND (probe, 0); | |
3591 | continue; | |
3592 | ||
3593 | default: | |
3594 | probe = NULL_TREE; | |
3595 | continue; | |
3596 | } | |
3597 | } | |
3598 | ||
9db9fc38 | 3599 | if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (target), type)) |
3600 | { | |
3601 | /* For initialization of an empty base, the original target will be | |
3602 | *(base*)this, which the above evaluation resolves to the object | |
3603 | argument, which has the derived type rather than the base type. In | |
3604 | this situation, just evaluate the initializer and return, since | |
3605 | there's no actual data to store. */ | |
3606 | gcc_assert (is_empty_class (type)); | |
3607 | return cxx_eval_constant_expression (ctx, init, false, | |
3608 | non_constant_p, overflow_p); | |
3609 | } | |
3610 | ||
9c96033c | 3611 | /* And then find the underlying variable. */ |
3612 | vec<tree,va_gc> *refs = make_tree_vector(); | |
3613 | tree object = NULL_TREE; | |
3614 | for (tree probe = target; object == NULL_TREE; ) | |
3615 | { | |
3616 | switch (TREE_CODE (probe)) | |
3617 | { | |
3618 | case BIT_FIELD_REF: | |
3619 | case COMPONENT_REF: | |
3620 | case ARRAY_REF: | |
3621 | vec_safe_push (refs, TREE_OPERAND (probe, 1)); | |
3622 | vec_safe_push (refs, TREE_TYPE (probe)); | |
3623 | probe = TREE_OPERAND (probe, 0); | |
3624 | break; | |
3625 | ||
3626 | default: | |
3627 | object = probe; | |
9c96033c | 3628 | } |
3629 | } | |
3630 | ||
3631 | /* And then find/build up our initializer for the path to the subobject | |
3632 | we're initializing. */ | |
6fe83e54 | 3633 | tree *valp; |
43b7271d | 3634 | if (object == ctx->object && VAR_P (object) |
3635 | && DECL_NAME (object) && ctx->call == NULL) | |
3636 | /* The variable we're building up an aggregate initializer for is outside | |
3637 | the constant-expression, so don't evaluate the store. We check | |
3638 | DECL_NAME to handle TARGET_EXPR temporaries, which are fair game. */ | |
3639 | valp = NULL; | |
3640 | else if (DECL_P (object)) | |
6fe83e54 | 3641 | valp = ctx->values->get (object); |
3642 | else | |
3643 | valp = NULL; | |
9c96033c | 3644 | if (!valp) |
3645 | { | |
3646 | /* A constant-expression cannot modify objects from outside the | |
3647 | constant-expression. */ | |
f83e6885 | 3648 | if (!ctx->quiet) |
ea034e2c | 3649 | error ("modification of %qE is not a constant expression", object); |
9c96033c | 3650 | *non_constant_p = true; |
3651 | return t; | |
3652 | } | |
9db9fc38 | 3653 | type = TREE_TYPE (object); |
a02b42fe | 3654 | bool no_zero_init = true; |
58b0f9ce | 3655 | |
3656 | vec<tree,va_gc> *ctors = make_tree_vector (); | |
9c96033c | 3657 | while (!refs->is_empty()) |
3658 | { | |
3659 | if (*valp == NULL_TREE) | |
3660 | { | |
3661 | *valp = build_constructor (type, NULL); | |
165d0d5b | 3662 | CONSTRUCTOR_NO_CLEARING (*valp) = no_zero_init; |
9c96033c | 3663 | } |
92fe8840 | 3664 | else if (TREE_CODE (*valp) == STRING_CST) |
3665 | { | |
3666 | /* An array was initialized with a string constant, and now | |
3667 | we're writing into one of its elements. Explode the | |
3668 | single initialization into a set of element | |
3669 | initializations. */ | |
3670 | gcc_assert (TREE_CODE (type) == ARRAY_TYPE); | |
3671 | ||
3672 | tree string = *valp; | |
3673 | tree elt_type = TREE_TYPE (type); | |
3674 | unsigned chars_per_elt = (TYPE_PRECISION (elt_type) | |
3675 | / TYPE_PRECISION (char_type_node)); | |
3676 | unsigned num_elts = TREE_STRING_LENGTH (string) / chars_per_elt; | |
3677 | tree ary_ctor = build_constructor (type, NULL); | |
3678 | ||
3679 | vec_safe_reserve (CONSTRUCTOR_ELTS (ary_ctor), num_elts); | |
3680 | for (unsigned ix = 0; ix != num_elts; ix++) | |
3681 | { | |
3682 | constructor_elt elt = | |
3683 | { | |
3684 | build_int_cst (size_type_node, ix), | |
3685 | extract_string_elt (string, chars_per_elt, ix) | |
3686 | }; | |
3687 | CONSTRUCTOR_ELTS (ary_ctor)->quick_push (elt); | |
3688 | } | |
3689 | ||
3690 | *valp = ary_ctor; | |
3691 | } | |
3692 | ||
a02b42fe | 3693 | /* If the value of object is already zero-initialized, any new ctors for |
3694 | subobjects will also be zero-initialized. */ | |
165d0d5b | 3695 | no_zero_init = CONSTRUCTOR_NO_CLEARING (*valp); |
9c96033c | 3696 | |
58b0f9ce | 3697 | vec_safe_push (ctors, *valp); |
3698 | ||
7963b19d | 3699 | enum tree_code code = TREE_CODE (type); |
9c96033c | 3700 | type = refs->pop(); |
7963b19d | 3701 | tree index = refs->pop(); |
9c96033c | 3702 | |
9c96033c | 3703 | constructor_elt *cep = NULL; |
7963b19d | 3704 | if (code == ARRAY_TYPE) |
3705 | { | |
3706 | HOST_WIDE_INT i | |
3707 | = find_array_ctor_elt (*valp, index, /*insert*/true); | |
3708 | gcc_assert (i >= 0); | |
3709 | cep = CONSTRUCTOR_ELT (*valp, i); | |
3710 | gcc_assert (TREE_CODE (cep->index) != RANGE_EXPR); | |
3711 | } | |
3712 | else | |
3713 | { | |
3714 | gcc_assert (TREE_CODE (index) == FIELD_DECL); | |
13ee2de7 | 3715 | |
3716 | /* We must keep the CONSTRUCTOR's ELTS in FIELD order. | |
3717 | Usually we meet initializers in that order, but it is | |
3718 | possible for base types to be placed not in program | |
3719 | order. */ | |
3720 | tree fields = TYPE_FIELDS (DECL_CONTEXT (index)); | |
3721 | unsigned HOST_WIDE_INT idx; | |
3722 | ||
ef782365 | 3723 | if (code == UNION_TYPE && CONSTRUCTOR_NELTS (*valp) |
3724 | && CONSTRUCTOR_ELT (*valp, 0)->index != index) | |
3725 | /* Changing active member. */ | |
3726 | vec_safe_truncate (CONSTRUCTOR_ELTS (*valp), 0); | |
3727 | ||
13ee2de7 | 3728 | for (idx = 0; |
7963b19d | 3729 | vec_safe_iterate (CONSTRUCTOR_ELTS (*valp), idx, &cep); |
13ee2de7 | 3730 | idx++, fields = DECL_CHAIN (fields)) |
7963b19d | 3731 | { |
13ee2de7 | 3732 | if (index == cep->index) |
3733 | goto found; | |
3734 | ||
3735 | /* The field we're initializing must be on the field | |
3736 | list. Look to see if it is present before the | |
3737 | field the current ELT initializes. */ | |
3738 | for (; fields != cep->index; fields = DECL_CHAIN (fields)) | |
3739 | if (index == fields) | |
3740 | goto insert; | |
7963b19d | 3741 | } |
13ee2de7 | 3742 | |
3743 | /* We fell off the end of the CONSTRUCTOR, so insert a new | |
3744 | entry at the end. */ | |
3745 | insert: | |
3746 | { | |
3747 | constructor_elt ce = { index, NULL_TREE }; | |
3748 | ||
3749 | vec_safe_insert (CONSTRUCTOR_ELTS (*valp), idx, ce); | |
3750 | cep = CONSTRUCTOR_ELT (*valp, idx); | |
3751 | } | |
3752 | found:; | |
7963b19d | 3753 | } |
9c96033c | 3754 | valp = &cep->value; |
3755 | } | |
3756 | release_tree_vector (refs); | |
3757 | ||
469dc5a6 | 3758 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) |
9c96033c | 3759 | { |
3760 | /* Create a new CONSTRUCTOR in case evaluation of the initializer | |
3761 | wants to modify it. */ | |
469dc5a6 | 3762 | if (*valp == NULL_TREE) |
6cded085 | 3763 | { |
6993e708 | 3764 | *valp = build_constructor (type, NULL); |
165d0d5b | 3765 | CONSTRUCTOR_NO_CLEARING (*valp) = no_zero_init; |
6cded085 | 3766 | } |
6993e708 | 3767 | else if (TREE_CODE (*valp) == PTRMEM_CST) |
3768 | *valp = cplus_expand_constant (*valp); | |
3769 | new_ctx.ctor = *valp; | |
9c96033c | 3770 | new_ctx.object = target; |
3771 | } | |
3772 | ||
8a36d0ec | 3773 | init = cxx_eval_constant_expression (&new_ctx, init, false, |
3774 | non_constant_p, overflow_p); | |
7b9f713d | 3775 | /* Don't share a CONSTRUCTOR that might be changed later. */ |
e283bb4f | 3776 | init = unshare_constructor (init); |
9c96033c | 3777 | if (target == object) |
5579a199 | 3778 | /* The hash table might have moved since the get earlier. */ |
3779 | valp = ctx->values->get (object); | |
3780 | ||
3781 | if (TREE_CODE (init) == CONSTRUCTOR) | |
469dc5a6 | 3782 | { |
5579a199 | 3783 | /* An outer ctx->ctor might be pointing to *valp, so replace |
3784 | its contents. */ | |
3785 | CONSTRUCTOR_ELTS (*valp) = CONSTRUCTOR_ELTS (init); | |
3786 | TREE_CONSTANT (*valp) = TREE_CONSTANT (init); | |
3787 | TREE_SIDE_EFFECTS (*valp) = TREE_SIDE_EFFECTS (init); | |
165d0d5b | 3788 | CONSTRUCTOR_NO_CLEARING (*valp) |
3789 | = CONSTRUCTOR_NO_CLEARING (init); | |
469dc5a6 | 3790 | } |
9c96033c | 3791 | else |
5579a199 | 3792 | *valp = init; |
58b0f9ce | 3793 | |
5579a199 | 3794 | /* Update TREE_CONSTANT and TREE_SIDE_EFFECTS on enclosing |
3795 | CONSTRUCTORs, if any. */ | |
3796 | tree elt; | |
3797 | unsigned i; | |
3798 | bool c = TREE_CONSTANT (init); | |
3799 | bool s = TREE_SIDE_EFFECTS (init); | |
3800 | if (!c || s) | |
3801 | FOR_EACH_VEC_SAFE_ELT (ctors, i, elt) | |
3802 | { | |
3803 | if (!c) | |
3804 | TREE_CONSTANT (elt) = false; | |
3805 | if (s) | |
3806 | TREE_SIDE_EFFECTS (elt) = true; | |
3807 | } | |
58b0f9ce | 3808 | release_tree_vector (ctors); |
9c96033c | 3809 | |
3810 | if (*non_constant_p) | |
3811 | return t; | |
1227ba74 | 3812 | else if (lval) |
9c96033c | 3813 | return target; |
3814 | else | |
dfac7dd2 | 3815 | return init; |
9c96033c | 3816 | } |
3817 | ||
3818 | /* Evaluate a ++ or -- expression. */ | |
3819 | ||
3820 | static tree | |
3821 | cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3822 | bool lval, |
9c96033c | 3823 | bool *non_constant_p, bool *overflow_p) |
3824 | { | |
3825 | enum tree_code code = TREE_CODE (t); | |
3826 | tree type = TREE_TYPE (t); | |
3827 | tree op = TREE_OPERAND (t, 0); | |
3828 | tree offset = TREE_OPERAND (t, 1); | |
3829 | gcc_assert (TREE_CONSTANT (offset)); | |
3830 | ||
3831 | /* The operand as an lvalue. */ | |
f83e6885 | 3832 | op = cxx_eval_constant_expression (ctx, op, true, |
b2a43197 | 3833 | non_constant_p, overflow_p); |
9c96033c | 3834 | |
3835 | /* The operand as an rvalue. */ | |
c017458d | 3836 | tree val |
3837 | = cxx_eval_constant_expression (ctx, op, false, | |
3838 | non_constant_p, overflow_p); | |
35f2c28f | 3839 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
3840 | a local array in a constexpr function. */ | |
d03fa520 | 3841 | bool ptr = INDIRECT_TYPE_P (TREE_TYPE (val)); |
35f2c28f | 3842 | if (!ptr) |
3843 | VERIFY_CONSTANT (val); | |
9c96033c | 3844 | |
3845 | /* The modified value. */ | |
3846 | bool inc = (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR); | |
c8a8f7ad | 3847 | tree mod; |
d03fa520 | 3848 | if (INDIRECT_TYPE_P (type)) |
c8a8f7ad | 3849 | { |
3850 | /* The middle end requires pointers to use POINTER_PLUS_EXPR. */ | |
3851 | offset = convert_to_ptrofftype (offset); | |
3852 | if (!inc) | |
3853 | offset = fold_build1 (NEGATE_EXPR, TREE_TYPE (offset), offset); | |
3854 | mod = fold_build2 (POINTER_PLUS_EXPR, type, val, offset); | |
3855 | } | |
3856 | else | |
3857 | mod = fold_build2 (inc ? PLUS_EXPR : MINUS_EXPR, type, val, offset); | |
35f2c28f | 3858 | if (!ptr) |
3859 | VERIFY_CONSTANT (mod); | |
9c96033c | 3860 | |
3861 | /* Storing the modified value. */ | |
3862 | tree store = build2 (MODIFY_EXPR, type, op, mod); | |
f83e6885 | 3863 | cxx_eval_constant_expression (ctx, store, |
b2a43197 | 3864 | true, non_constant_p, overflow_p); |
9c96033c | 3865 | |
3866 | /* And the value of the expression. */ | |
3867 | if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) | |
3868 | { | |
3869 | /* Prefix ops are lvalues. */ | |
1227ba74 | 3870 | if (lval) |
9c96033c | 3871 | return op; |
3872 | else | |
3873 | /* But we optimize when the caller wants an rvalue. */ | |
3874 | return mod; | |
3875 | } | |
3876 | else | |
3877 | /* Postfix ops are rvalues. */ | |
3878 | return val; | |
3879 | } | |
3880 | ||
00f21715 | 3881 | /* Predicates for the meaning of *jump_target. */ |
3882 | ||
3883 | static bool | |
3884 | returns (tree *jump_target) | |
3885 | { | |
3886 | return *jump_target | |
d29e4e8c | 3887 | && (TREE_CODE (*jump_target) == RETURN_EXPR |
3888 | || (TREE_CODE (*jump_target) == LABEL_DECL | |
3889 | && LABEL_DECL_CDTOR (*jump_target))); | |
00f21715 | 3890 | } |
3891 | ||
3892 | static bool | |
3893 | breaks (tree *jump_target) | |
3894 | { | |
3895 | return *jump_target | |
cf03ba19 | 3896 | && ((TREE_CODE (*jump_target) == LABEL_DECL |
3897 | && LABEL_DECL_BREAK (*jump_target)) | |
3898 | || TREE_CODE (*jump_target) == EXIT_EXPR); | |
00f21715 | 3899 | } |
3900 | ||
3901 | static bool | |
3902 | continues (tree *jump_target) | |
3903 | { | |
3904 | return *jump_target | |
3905 | && TREE_CODE (*jump_target) == LABEL_DECL | |
3906 | && LABEL_DECL_CONTINUE (*jump_target); | |
3907 | } | |
3908 | ||
3909 | static bool | |
3910 | switches (tree *jump_target) | |
3911 | { | |
3912 | return *jump_target | |
3913 | && TREE_CODE (*jump_target) == INTEGER_CST; | |
3914 | } | |
3915 | ||
3916 | /* Subroutine of cxx_eval_statement_list. Determine whether the statement | |
2a2770c6 | 3917 | STMT matches *jump_target. If we're looking for a case label and we see |
3918 | the default label, note it in ctx->css_state. */ | |
00f21715 | 3919 | |
3920 | static bool | |
2a2770c6 | 3921 | label_matches (const constexpr_ctx *ctx, tree *jump_target, tree stmt) |
00f21715 | 3922 | { |
00f21715 | 3923 | switch (TREE_CODE (*jump_target)) |
3924 | { | |
3925 | case LABEL_DECL: | |
3926 | if (TREE_CODE (stmt) == LABEL_EXPR | |
3927 | && LABEL_EXPR_LABEL (stmt) == *jump_target) | |
3928 | return true; | |
3929 | break; | |
3930 | ||
3931 | case INTEGER_CST: | |
3932 | if (TREE_CODE (stmt) == CASE_LABEL_EXPR) | |
3933 | { | |
2a2770c6 | 3934 | gcc_assert (ctx->css_state != NULL); |
00f21715 | 3935 | if (!CASE_LOW (stmt)) |
2a2770c6 | 3936 | { |
3937 | /* default: should appear just once in a SWITCH_EXPR | |
3938 | body (excluding nested SWITCH_EXPR). */ | |
3939 | gcc_assert (*ctx->css_state != css_default_seen); | |
3940 | /* When evaluating SWITCH_EXPR body for the second time, | |
3941 | return true for the default: label. */ | |
3942 | if (*ctx->css_state == css_default_processing) | |
3943 | return true; | |
3944 | *ctx->css_state = css_default_seen; | |
3945 | } | |
83c375ba | 3946 | else if (CASE_HIGH (stmt)) |
3947 | { | |
3948 | if (tree_int_cst_le (CASE_LOW (stmt), *jump_target) | |
3949 | && tree_int_cst_le (*jump_target, CASE_HIGH (stmt))) | |
3950 | return true; | |
3951 | } | |
00f21715 | 3952 | else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt))) |
3953 | return true; | |
3954 | } | |
3955 | break; | |
3956 | ||
3957 | default: | |
3958 | gcc_unreachable (); | |
3959 | } | |
3960 | return false; | |
3961 | } | |
3962 | ||
3963 | /* Evaluate a STATEMENT_LIST for side-effects. Handles various jump | |
3964 | semantics, for switch, break, continue, and return. */ | |
3965 | ||
3966 | static tree | |
3967 | cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3968 | bool *non_constant_p, bool *overflow_p, |
3969 | tree *jump_target) | |
3970 | { | |
3971 | tree_stmt_iterator i; | |
da7981e0 | 3972 | tree local_target; |
efea7c64 | 3973 | /* In a statement-expression we want to return the last value. |
3974 | For empty statement expression return void_node. */ | |
3975 | tree r = void_node; | |
da7981e0 | 3976 | if (!jump_target) |
3977 | { | |
3978 | local_target = NULL_TREE; | |
3979 | jump_target = &local_target; | |
3980 | } | |
00f21715 | 3981 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) |
3982 | { | |
00f21715 | 3983 | tree stmt = tsi_stmt (i); |
ba0f90e4 | 3984 | /* We've found a continue, so skip everything until we reach |
3985 | the label its jumping to. */ | |
3986 | if (continues (jump_target)) | |
3987 | { | |
3988 | if (label_matches (ctx, jump_target, stmt)) | |
3989 | /* Found it. */ | |
3990 | *jump_target = NULL_TREE; | |
3991 | else | |
3992 | continue; | |
3993 | } | |
442c4003 | 3994 | if (TREE_CODE (stmt) == DEBUG_BEGIN_STMT) |
3995 | continue; | |
da7981e0 | 3996 | r = cxx_eval_constant_expression (ctx, stmt, false, |
3997 | non_constant_p, overflow_p, | |
3998 | jump_target); | |
00f21715 | 3999 | if (*non_constant_p) |
4000 | break; | |
4001 | if (returns (jump_target) || breaks (jump_target)) | |
4002 | break; | |
4003 | } | |
da7981e0 | 4004 | return r; |
00f21715 | 4005 | } |
4006 | ||
4007 | /* Evaluate a LOOP_EXPR for side-effects. Handles break and return | |
4008 | semantics; continue semantics are covered by cxx_eval_statement_list. */ | |
4009 | ||
4010 | static tree | |
4011 | cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 4012 | bool *non_constant_p, bool *overflow_p, |
4013 | tree *jump_target) | |
4014 | { | |
2631cb67 | 4015 | constexpr_ctx new_ctx = *ctx; |
4016 | ||
00f21715 | 4017 | tree body = TREE_OPERAND (t, 0); |
21483ab7 | 4018 | int count = 0; |
5370eb8d | 4019 | do |
00f21715 | 4020 | { |
2631cb67 | 4021 | hash_set<tree> save_exprs; |
4022 | new_ctx.save_exprs = &save_exprs; | |
4023 | ||
cf03ba19 | 4024 | cxx_eval_constant_expression (&new_ctx, body, /*lval*/false, |
4025 | non_constant_p, overflow_p, jump_target); | |
2631cb67 | 4026 | |
4027 | /* Forget saved values of SAVE_EXPRs. */ | |
4028 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
4029 | iter != save_exprs.end(); ++iter) | |
4030 | new_ctx.values->remove (*iter); | |
21483ab7 | 4031 | if (++count >= constexpr_loop_limit) |
4032 | { | |
4033 | if (!ctx->quiet) | |
d3a3cfb8 | 4034 | error_at (cp_expr_loc_or_loc (t, input_location), |
5967b28b | 4035 | "%<constexpr%> loop iteration count exceeds limit of %d " |
21483ab7 | 4036 | "(use -fconstexpr-loop-limit= to increase the limit)", |
4037 | constexpr_loop_limit); | |
4038 | *non_constant_p = true; | |
4039 | break; | |
4040 | } | |
00f21715 | 4041 | } |
2a2770c6 | 4042 | while (!returns (jump_target) |
4043 | && !breaks (jump_target) | |
4044 | && !switches (jump_target) | |
4045 | && !*non_constant_p); | |
5370eb8d | 4046 | |
00f21715 | 4047 | if (breaks (jump_target)) |
4048 | *jump_target = NULL_TREE; | |
2631cb67 | 4049 | |
00f21715 | 4050 | return NULL_TREE; |
4051 | } | |
4052 | ||
4053 | /* Evaluate a SWITCH_EXPR for side-effects. Handles switch and break jump | |
4054 | semantics. */ | |
4055 | ||
4056 | static tree | |
4057 | cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 4058 | bool *non_constant_p, bool *overflow_p, |
4059 | tree *jump_target) | |
4060 | { | |
4061 | tree cond = TREE_OPERAND (t, 0); | |
f83e6885 | 4062 | cond = cxx_eval_constant_expression (ctx, cond, false, |
b2a43197 | 4063 | non_constant_p, overflow_p); |
00f21715 | 4064 | VERIFY_CONSTANT (cond); |
4065 | *jump_target = cond; | |
4066 | ||
4067 | tree body = TREE_OPERAND (t, 1); | |
2a2770c6 | 4068 | constexpr_ctx new_ctx = *ctx; |
4069 | constexpr_switch_state css = css_default_not_seen; | |
4070 | new_ctx.css_state = &css; | |
4071 | cxx_eval_constant_expression (&new_ctx, body, false, | |
4072 | non_constant_p, overflow_p, jump_target); | |
4073 | if (switches (jump_target) && css == css_default_seen) | |
4074 | { | |
4075 | /* If the SWITCH_EXPR body has default: label, process it once again, | |
4076 | this time instructing label_matches to return true for default: | |
4077 | label on switches (jump_target). */ | |
4078 | css = css_default_processing; | |
4079 | cxx_eval_constant_expression (&new_ctx, body, false, | |
4080 | non_constant_p, overflow_p, jump_target); | |
4081 | } | |
00f21715 | 4082 | if (breaks (jump_target) || switches (jump_target)) |
4083 | *jump_target = NULL_TREE; | |
4084 | return NULL_TREE; | |
4085 | } | |
4086 | ||
85de9604 | 4087 | /* Find the object of TYPE under initialization in CTX. */ |
4088 | ||
4089 | static tree | |
4090 | lookup_placeholder (const constexpr_ctx *ctx, bool lval, tree type) | |
4091 | { | |
def8e41f | 4092 | if (!ctx) |
85de9604 | 4093 | return NULL_TREE; |
4094 | ||
4095 | /* We could use ctx->object unconditionally, but using ctx->ctor when we | |
4096 | can is a minor optimization. */ | |
def8e41f | 4097 | if (!lval && ctx->ctor && same_type_p (TREE_TYPE (ctx->ctor), type)) |
85de9604 | 4098 | return ctx->ctor; |
4099 | ||
def8e41f | 4100 | if (!ctx->object) |
4101 | return NULL_TREE; | |
4102 | ||
85de9604 | 4103 | /* Since an object cannot have a field of its own type, we can search outward |
4104 | from ctx->object to find the unique containing object of TYPE. */ | |
4105 | tree ob = ctx->object; | |
4106 | while (ob) | |
4107 | { | |
4108 | if (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (ob), type)) | |
4109 | break; | |
4110 | if (handled_component_p (ob)) | |
4111 | ob = TREE_OPERAND (ob, 0); | |
4112 | else | |
4113 | ob = NULL_TREE; | |
4114 | } | |
4115 | ||
4116 | return ob; | |
4117 | } | |
4118 | ||
09b42213 | 4119 | /* Attempt to reduce the expression T to a constant value. |
4120 | On failure, issue diagnostic and return error_mark_node. */ | |
4121 | /* FIXME unify with c_fully_fold */ | |
9c96033c | 4122 | /* FIXME overflow_p is too global */ |
09b42213 | 4123 | |
4124 | static tree | |
cf72f34d | 4125 | cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 4126 | bool lval, |
00f21715 | 4127 | bool *non_constant_p, bool *overflow_p, |
4128 | tree *jump_target) | |
09b42213 | 4129 | { |
cf72f34d | 4130 | constexpr_ctx new_ctx; |
09b42213 | 4131 | tree r = t; |
4132 | ||
2a2770c6 | 4133 | if (jump_target && *jump_target) |
4134 | { | |
4135 | /* If we are jumping, ignore all statements/expressions except those | |
4136 | that could have LABEL_EXPR or CASE_LABEL_EXPR in their bodies. */ | |
4137 | switch (TREE_CODE (t)) | |
4138 | { | |
4139 | case BIND_EXPR: | |
4140 | case STATEMENT_LIST: | |
4141 | case LOOP_EXPR: | |
4142 | case COND_EXPR: | |
4143 | break; | |
4144 | case LABEL_EXPR: | |
4145 | case CASE_LABEL_EXPR: | |
4146 | if (label_matches (ctx, jump_target, t)) | |
4147 | /* Found it. */ | |
4148 | *jump_target = NULL_TREE; | |
4149 | return NULL_TREE; | |
4150 | default: | |
4151 | return NULL_TREE; | |
4152 | } | |
4153 | } | |
09b42213 | 4154 | if (t == error_mark_node) |
4155 | { | |
4156 | *non_constant_p = true; | |
4157 | return t; | |
4158 | } | |
4159 | if (CONSTANT_CLASS_P (t)) | |
4160 | { | |
c4fa85c9 | 4161 | if (TREE_OVERFLOW (t)) |
4162 | { | |
4163 | if (!ctx->quiet) | |
4164 | permerror (input_location, "overflow in constant expression"); | |
4165 | if (!flag_permissive || ctx->quiet) | |
4166 | *overflow_p = true; | |
4167 | } | |
cb768824 | 4168 | |
4169 | if (TREE_CODE (t) == INTEGER_CST | |
90ad495b | 4170 | && TYPE_PTR_P (TREE_TYPE (t)) |
cb768824 | 4171 | && !integer_zerop (t)) |
4172 | { | |
4173 | if (!ctx->quiet) | |
4174 | error ("value %qE of type %qT is not a constant expression", | |
4175 | t, TREE_TYPE (t)); | |
4176 | *non_constant_p = true; | |
4177 | } | |
4178 | ||
09b42213 | 4179 | return t; |
4180 | } | |
09b42213 | 4181 | |
cb768824 | 4182 | tree_code tcode = TREE_CODE (t); |
4183 | switch (tcode) | |
09b42213 | 4184 | { |
9c96033c | 4185 | case RESULT_DECL: |
1227ba74 | 4186 | if (lval) |
9c96033c | 4187 | return t; |
4188 | /* We ask for an rvalue for the RESULT_DECL when indirecting | |
92a9c89e | 4189 | through an invisible reference, or in named return value |
4190 | optimization. */ | |
8ea8d065 | 4191 | if (tree *p = ctx->values->get (t)) |
4192 | return *p; | |
4193 | else | |
4194 | { | |
4195 | if (!ctx->quiet) | |
4196 | error ("%qE is not a constant expression", t); | |
4197 | *non_constant_p = true; | |
4198 | } | |
4199 | break; | |
9c96033c | 4200 | |
09b42213 | 4201 | case VAR_DECL: |
9c8aeb66 | 4202 | if (DECL_HAS_VALUE_EXPR_P (t)) |
33603066 | 4203 | return cxx_eval_constant_expression (ctx, DECL_VALUE_EXPR (t), |
4204 | lval, non_constant_p, overflow_p); | |
e3533433 | 4205 | /* fall through */ |
8b2b2f24 | 4206 | case CONST_DECL: |
4207 | /* We used to not check lval for CONST_DECL, but darwin.c uses | |
4208 | CONST_DECL for aggregate constants. */ | |
1227ba74 | 4209 | if (lval) |
09b42213 | 4210 | return t; |
594cc00c | 4211 | if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
4212 | && is_really_empty_class (TREE_TYPE (t))) | |
c7282bf2 | 4213 | { |
4214 | /* If the class is empty, we aren't actually loading anything. */ | |
4215 | r = build_constructor (TREE_TYPE (t), NULL); | |
4216 | TREE_CONSTANT (r) = true; | |
4217 | } | |
4218 | else if (ctx->strict) | |
2055d27a | 4219 | r = decl_really_constant_value (t); |
4220 | else | |
4221 | r = decl_constant_value (t); | |
09b42213 | 4222 | if (TREE_CODE (r) == TARGET_EXPR |
4223 | && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR) | |
4224 | r = TARGET_EXPR_INITIAL (r); | |
f4ae4202 | 4225 | if (VAR_P (r)) |
cf72f34d | 4226 | if (tree *p = ctx->values->get (r)) |
a143e277 | 4227 | if (*p != NULL_TREE) |
4228 | r = *p; | |
09b42213 | 4229 | if (DECL_P (r)) |
4230 | { | |
f83e6885 | 4231 | if (!ctx->quiet) |
09b42213 | 4232 | non_const_var_error (r); |
4233 | *non_constant_p = true; | |
4234 | } | |
4235 | break; | |
4236 | ||
90567983 | 4237 | case DEBUG_BEGIN_STMT: |
4238 | /* ??? It might be nice to retain this information somehow, so | |
4239 | as to be able to step into a constexpr function call. */ | |
4240 | /* Fall through. */ | |
4241 | ||
09b42213 | 4242 | case FUNCTION_DECL: |
4243 | case TEMPLATE_DECL: | |
4244 | case LABEL_DECL: | |
00f21715 | 4245 | case LABEL_EXPR: |
4246 | case CASE_LABEL_EXPR: | |
2a2770c6 | 4247 | case PREDICT_EXPR: |
09b42213 | 4248 | return t; |
4249 | ||
4250 | case PARM_DECL: | |
90ad495b | 4251 | if (lval && !TYPE_REF_P (TREE_TYPE (t))) |
9c96033c | 4252 | /* glvalue use. */; |
4253 | else if (tree *p = ctx->values->get (r)) | |
4254 | r = *p; | |
1227ba74 | 4255 | else if (lval) |
09b42213 | 4256 | /* Defer in case this is only used for its type. */; |
90ad495b | 4257 | else if (TYPE_REF_P (TREE_TYPE (t))) |
1eb418cc | 4258 | /* Defer, there's no lvalue->rvalue conversion. */; |
53d2f3de | 4259 | else if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
4260 | && is_really_empty_class (TREE_TYPE (t))) | |
a6613de7 | 4261 | { |
4262 | /* If the class is empty, we aren't actually loading anything. */ | |
4263 | r = build_constructor (TREE_TYPE (t), NULL); | |
4264 | TREE_CONSTANT (r) = true; | |
4265 | } | |
09b42213 | 4266 | else |
4267 | { | |
f83e6885 | 4268 | if (!ctx->quiet) |
09b42213 | 4269 | error ("%qE is not a constant expression", t); |
4270 | *non_constant_p = true; | |
4271 | } | |
4272 | break; | |
4273 | ||
4274 | case CALL_EXPR: | |
4275 | case AGGR_INIT_EXPR: | |
1227ba74 | 4276 | r = cxx_eval_call_expression (ctx, t, lval, |
09b42213 | 4277 | non_constant_p, overflow_p); |
4278 | break; | |
4279 | ||
9c96033c | 4280 | case DECL_EXPR: |
4281 | { | |
4282 | r = DECL_EXPR_DECL (t); | |
4283 | if (AGGREGATE_TYPE_P (TREE_TYPE (r)) | |
4284 | || VECTOR_TYPE_P (TREE_TYPE (r))) | |
4285 | { | |
4286 | new_ctx = *ctx; | |
4287 | new_ctx.object = r; | |
4288 | new_ctx.ctor = build_constructor (TREE_TYPE (r), NULL); | |
165d0d5b | 4289 | CONSTRUCTOR_NO_CLEARING (new_ctx.ctor) = true; |
9c96033c | 4290 | new_ctx.values->put (r, new_ctx.ctor); |
4291 | ctx = &new_ctx; | |
4292 | } | |
4293 | ||
4294 | if (tree init = DECL_INITIAL (r)) | |
4295 | { | |
4296 | init = cxx_eval_constant_expression (ctx, init, | |
f83e6885 | 4297 | false, |
b2a43197 | 4298 | non_constant_p, overflow_p); |
5898f0d7 | 4299 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 4300 | init = unshare_constructor (init); |
9c96033c | 4301 | ctx->values->put (r, init); |
4302 | } | |
4303 | else if (ctx == &new_ctx) | |
4304 | /* We gave it a CONSTRUCTOR above. */; | |
4305 | else | |
4306 | ctx->values->put (r, NULL_TREE); | |
4307 | } | |
4308 | break; | |
4309 | ||
09b42213 | 4310 | case TARGET_EXPR: |
4311 | if (!literal_type_p (TREE_TYPE (t))) | |
4312 | { | |
f83e6885 | 4313 | if (!ctx->quiet) |
09b42213 | 4314 | { |
bc35ef65 | 4315 | auto_diagnostic_group d; |
09b42213 | 4316 | error ("temporary of non-literal type %qT in a " |
4317 | "constant expression", TREE_TYPE (t)); | |
4318 | explain_non_literal_class (TREE_TYPE (t)); | |
4319 | } | |
4320 | *non_constant_p = true; | |
4321 | break; | |
4322 | } | |
cf72f34d | 4323 | if ((AGGREGATE_TYPE_P (TREE_TYPE (t)) || VECTOR_TYPE_P (TREE_TYPE (t)))) |
4324 | { | |
4325 | /* We're being expanded without an explicit target, so start | |
4326 | initializing a new object; expansion with an explicit target | |
4327 | strips the TARGET_EXPR before we get here. */ | |
4328 | new_ctx = *ctx; | |
4329 | new_ctx.ctor = build_constructor (TREE_TYPE (t), NULL); | |
165d0d5b | 4330 | CONSTRUCTOR_NO_CLEARING (new_ctx.ctor) = true; |
cf72f34d | 4331 | new_ctx.object = TARGET_EXPR_SLOT (t); |
4332 | ctx->values->put (new_ctx.object, new_ctx.ctor); | |
4333 | ctx = &new_ctx; | |
4334 | } | |
1227ba74 | 4335 | /* Pass false for 'lval' because this indicates |
09b42213 | 4336 | initialization of a temporary. */ |
cf72f34d | 4337 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 4338 | false, |
b2a43197 | 4339 | non_constant_p, overflow_p); |
09b42213 | 4340 | if (!*non_constant_p) |
4341 | /* Adjust the type of the result to the type of the temporary. */ | |
4342 | r = adjust_temp_type (TREE_TYPE (t), r); | |
1227ba74 | 4343 | if (lval) |
1eb418cc | 4344 | { |
4345 | tree slot = TARGET_EXPR_SLOT (t); | |
e283bb4f | 4346 | r = unshare_constructor (r); |
1eb418cc | 4347 | ctx->values->put (slot, r); |
4348 | return slot; | |
4349 | } | |
09b42213 | 4350 | break; |
4351 | ||
9c96033c | 4352 | case INIT_EXPR: |
9c96033c | 4353 | case MODIFY_EXPR: |
2a2770c6 | 4354 | gcc_assert (jump_target == NULL || *jump_target == NULL_TREE); |
1227ba74 | 4355 | r = cxx_eval_store_expression (ctx, t, lval, |
9c96033c | 4356 | non_constant_p, overflow_p); |
4357 | break; | |
4358 | ||
09b42213 | 4359 | case SCOPE_REF: |
cf72f34d | 4360 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 4361 | lval, |
b2a43197 | 4362 | non_constant_p, overflow_p); |
09b42213 | 4363 | break; |
4364 | ||
4365 | case RETURN_EXPR: | |
10fb495c | 4366 | if (TREE_OPERAND (t, 0) != NULL_TREE) |
4367 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
4368 | lval, | |
4369 | non_constant_p, overflow_p); | |
2c572f5f | 4370 | if (jump_target) |
4371 | *jump_target = t; | |
4372 | else | |
4373 | { | |
4374 | /* Can happen with ({ return true; }) && false; passed to | |
4375 | maybe_constant_value. There is nothing to jump over in this | |
4376 | case, and the bug will be diagnosed later. */ | |
4377 | gcc_assert (ctx->quiet); | |
4378 | *non_constant_p = true; | |
4379 | } | |
00f21715 | 4380 | break; |
4381 | ||
e0e672a0 | 4382 | case SAVE_EXPR: |
4383 | /* Avoid evaluating a SAVE_EXPR more than once. */ | |
4384 | if (tree *p = ctx->values->get (t)) | |
4385 | r = *p; | |
4386 | else | |
4387 | { | |
c8f6aeb1 | 4388 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), false, |
e0e672a0 | 4389 | non_constant_p, overflow_p); |
4390 | ctx->values->put (t, r); | |
2631cb67 | 4391 | if (ctx->save_exprs) |
4392 | ctx->save_exprs->add (t); | |
e0e672a0 | 4393 | } |
4394 | break; | |
4395 | ||
09b42213 | 4396 | case NON_LVALUE_EXPR: |
4397 | case TRY_CATCH_EXPR: | |
7f67d68c | 4398 | case TRY_BLOCK: |
09b42213 | 4399 | case CLEANUP_POINT_EXPR: |
4400 | case MUST_NOT_THROW_EXPR: | |
9c96033c | 4401 | case EXPR_STMT: |
4402 | case EH_SPEC_BLOCK: | |
cf72f34d | 4403 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 4404 | lval, |
00f21715 | 4405 | non_constant_p, overflow_p, |
4406 | jump_target); | |
09b42213 | 4407 | break; |
4408 | ||
7f67d68c | 4409 | case TRY_FINALLY_EXPR: |
4410 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4411 | non_constant_p, overflow_p, | |
4412 | jump_target); | |
4413 | if (!*non_constant_p) | |
4414 | /* Also evaluate the cleanup. */ | |
4415 | cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), true, | |
4416 | non_constant_p, overflow_p, | |
4417 | jump_target); | |
4418 | break; | |
4419 | ||
09b42213 | 4420 | /* These differ from cxx_eval_unary_expression in that this doesn't |
4421 | check for a constant operand or result; an address can be | |
4422 | constant without its operand being, and vice versa. */ | |
d2c63826 | 4423 | case MEM_REF: |
09b42213 | 4424 | case INDIRECT_REF: |
1227ba74 | 4425 | r = cxx_eval_indirect_ref (ctx, t, lval, |
09b42213 | 4426 | non_constant_p, overflow_p); |
4427 | break; | |
4428 | ||
4429 | case ADDR_EXPR: | |
4430 | { | |
4431 | tree oldop = TREE_OPERAND (t, 0); | |
cf72f34d | 4432 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4433 | /*lval*/true, |
b2a43197 | 4434 | non_constant_p, overflow_p); |
09b42213 | 4435 | /* Don't VERIFY_CONSTANT here. */ |
4436 | if (*non_constant_p) | |
4437 | return t; | |
1eb418cc | 4438 | gcc_checking_assert (TREE_CODE (op) != CONSTRUCTOR); |
09b42213 | 4439 | /* This function does more aggressive folding than fold itself. */ |
4440 | r = build_fold_addr_expr_with_type (op, TREE_TYPE (t)); | |
4441 | if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop) | |
4442 | return t; | |
4443 | break; | |
4444 | } | |
4445 | ||
4446 | case REALPART_EXPR: | |
4447 | case IMAGPART_EXPR: | |
6fe424c2 | 4448 | if (lval) |
4449 | { | |
4450 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4451 | non_constant_p, overflow_p); | |
4452 | if (r == error_mark_node) | |
4453 | ; | |
4454 | else if (r == TREE_OPERAND (t, 0)) | |
4455 | r = t; | |
4456 | else | |
4457 | r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), r); | |
4458 | break; | |
4459 | } | |
4460 | /* FALLTHRU */ | |
09b42213 | 4461 | case CONJ_EXPR: |
4462 | case FIX_TRUNC_EXPR: | |
4463 | case FLOAT_EXPR: | |
4464 | case NEGATE_EXPR: | |
4465 | case ABS_EXPR: | |
19b4138e | 4466 | case ABSU_EXPR: |
09b42213 | 4467 | case BIT_NOT_EXPR: |
4468 | case TRUTH_NOT_EXPR: | |
4469 | case FIXED_CONVERT_EXPR: | |
1227ba74 | 4470 | r = cxx_eval_unary_expression (ctx, t, lval, |
09b42213 | 4471 | non_constant_p, overflow_p); |
4472 | break; | |
4473 | ||
4474 | case SIZEOF_EXPR: | |
d2c63826 | 4475 | r = fold_sizeof_expr (t); |
09b42213 | 4476 | VERIFY_CONSTANT (r); |
4477 | break; | |
4478 | ||
4479 | case COMPOUND_EXPR: | |
4480 | { | |
4481 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
4482 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
4483 | introduced by build_call_a. */ | |
4484 | tree op0 = TREE_OPERAND (t, 0); | |
4485 | tree op1 = TREE_OPERAND (t, 1); | |
4486 | STRIP_NOPS (op1); | |
4487 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
4488 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
f83e6885 | 4489 | r = cxx_eval_constant_expression (ctx, op0, |
1227ba74 | 4490 | lval, non_constant_p, overflow_p, |
00f21715 | 4491 | jump_target); |
09b42213 | 4492 | else |
4493 | { | |
4494 | /* Check that the LHS is constant and then discard it. */ | |
f83e6885 | 4495 | cxx_eval_constant_expression (ctx, op0, |
c8f6aeb1 | 4496 | true, non_constant_p, overflow_p, |
00f21715 | 4497 | jump_target); |
cf03ba19 | 4498 | if (*non_constant_p) |
4499 | return t; | |
09b42213 | 4500 | op1 = TREE_OPERAND (t, 1); |
f83e6885 | 4501 | r = cxx_eval_constant_expression (ctx, op1, |
1227ba74 | 4502 | lval, non_constant_p, overflow_p, |
00f21715 | 4503 | jump_target); |
09b42213 | 4504 | } |
4505 | } | |
4506 | break; | |
4507 | ||
4508 | case POINTER_PLUS_EXPR: | |
57e83b58 | 4509 | case POINTER_DIFF_EXPR: |
09b42213 | 4510 | case PLUS_EXPR: |
4511 | case MINUS_EXPR: | |
4512 | case MULT_EXPR: | |
4513 | case TRUNC_DIV_EXPR: | |
4514 | case CEIL_DIV_EXPR: | |
4515 | case FLOOR_DIV_EXPR: | |
4516 | case ROUND_DIV_EXPR: | |
4517 | case TRUNC_MOD_EXPR: | |
4518 | case CEIL_MOD_EXPR: | |
4519 | case ROUND_MOD_EXPR: | |
4520 | case RDIV_EXPR: | |
4521 | case EXACT_DIV_EXPR: | |
4522 | case MIN_EXPR: | |
4523 | case MAX_EXPR: | |
4524 | case LSHIFT_EXPR: | |
4525 | case RSHIFT_EXPR: | |
4526 | case LROTATE_EXPR: | |
4527 | case RROTATE_EXPR: | |
4528 | case BIT_IOR_EXPR: | |
4529 | case BIT_XOR_EXPR: | |
4530 | case BIT_AND_EXPR: | |
4531 | case TRUTH_XOR_EXPR: | |
4532 | case LT_EXPR: | |
4533 | case LE_EXPR: | |
4534 | case GT_EXPR: | |
4535 | case GE_EXPR: | |
4536 | case EQ_EXPR: | |
4537 | case NE_EXPR: | |
4538 | case UNORDERED_EXPR: | |
4539 | case ORDERED_EXPR: | |
4540 | case UNLT_EXPR: | |
4541 | case UNLE_EXPR: | |
4542 | case UNGT_EXPR: | |
4543 | case UNGE_EXPR: | |
4544 | case UNEQ_EXPR: | |
4545 | case LTGT_EXPR: | |
4546 | case RANGE_EXPR: | |
4547 | case COMPLEX_EXPR: | |
1227ba74 | 4548 | r = cxx_eval_binary_expression (ctx, t, lval, |
09b42213 | 4549 | non_constant_p, overflow_p); |
4550 | break; | |
4551 | ||
4552 | /* fold can introduce non-IF versions of these; still treat them as | |
4553 | short-circuiting. */ | |
4554 | case TRUTH_AND_EXPR: | |
4555 | case TRUTH_ANDIF_EXPR: | |
cf72f34d | 4556 | r = cxx_eval_logical_expression (ctx, t, boolean_false_node, |
09b42213 | 4557 | boolean_true_node, |
1227ba74 | 4558 | lval, |
09b42213 | 4559 | non_constant_p, overflow_p); |
4560 | break; | |
4561 | ||
4562 | case TRUTH_OR_EXPR: | |
4563 | case TRUTH_ORIF_EXPR: | |
cf72f34d | 4564 | r = cxx_eval_logical_expression (ctx, t, boolean_true_node, |
09b42213 | 4565 | boolean_false_node, |
1227ba74 | 4566 | lval, |
09b42213 | 4567 | non_constant_p, overflow_p); |
4568 | break; | |
4569 | ||
4570 | case ARRAY_REF: | |
1227ba74 | 4571 | r = cxx_eval_array_reference (ctx, t, lval, |
09b42213 | 4572 | non_constant_p, overflow_p); |
4573 | break; | |
4574 | ||
4575 | case COMPONENT_REF: | |
4576 | if (is_overloaded_fn (t)) | |
4577 | { | |
4578 | /* We can only get here in checking mode via | |
4579 | build_non_dependent_expr, because any expression that | |
4580 | calls or takes the address of the function will have | |
4581 | pulled a FUNCTION_DECL out of the COMPONENT_REF. */ | |
f83e6885 | 4582 | gcc_checking_assert (ctx->quiet || errorcount); |
09b42213 | 4583 | *non_constant_p = true; |
4584 | return t; | |
4585 | } | |
1227ba74 | 4586 | r = cxx_eval_component_reference (ctx, t, lval, |
09b42213 | 4587 | non_constant_p, overflow_p); |
4588 | break; | |
4589 | ||
4590 | case BIT_FIELD_REF: | |
1227ba74 | 4591 | r = cxx_eval_bit_field_ref (ctx, t, lval, |
09b42213 | 4592 | non_constant_p, overflow_p); |
4593 | break; | |
4594 | ||
4595 | case COND_EXPR: | |
2a2770c6 | 4596 | if (jump_target && *jump_target) |
4597 | { | |
4598 | /* When jumping to a label, the label might be either in the | |
4599 | then or else blocks, so process then block first in skipping | |
4600 | mode first, and if we are still in the skipping mode at its end, | |
4601 | process the else block too. */ | |
4602 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
4603 | lval, non_constant_p, overflow_p, | |
4604 | jump_target); | |
4605 | if (*jump_target) | |
4606 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
4607 | lval, non_constant_p, overflow_p, | |
4608 | jump_target); | |
4609 | break; | |
4610 | } | |
1227ba74 | 4611 | r = cxx_eval_conditional_expression (ctx, t, lval, |
00f21715 | 4612 | non_constant_p, overflow_p, |
4613 | jump_target); | |
09b42213 | 4614 | break; |
31595caf | 4615 | case VEC_COND_EXPR: |
4616 | r = cxx_eval_vector_conditional_expression (ctx, t, non_constant_p, | |
4617 | overflow_p); | |
4618 | break; | |
09b42213 | 4619 | |
4620 | case CONSTRUCTOR: | |
1a3631bc | 4621 | if (TREE_CONSTANT (t)) |
58b0f9ce | 4622 | { |
4623 | /* Don't re-process a constant CONSTRUCTOR, but do fold it to | |
4624 | VECTOR_CST if applicable. */ | |
79e65a6b | 4625 | verify_constructor_flags (t); |
58b0f9ce | 4626 | if (TREE_CONSTANT (t)) |
4627 | return fold (t); | |
4628 | } | |
1227ba74 | 4629 | r = cxx_eval_bare_aggregate (ctx, t, lval, |
09b42213 | 4630 | non_constant_p, overflow_p); |
4631 | break; | |
4632 | ||
4633 | case VEC_INIT_EXPR: | |
4634 | /* We can get this in a defaulted constructor for a class with a | |
4635 | non-static data member of array type. Either the initializer will | |
4636 | be NULL, meaning default-initialization, or it will be an lvalue | |
4637 | or xvalue of the same type, meaning direct-initialization from the | |
4638 | corresponding member. */ | |
1227ba74 | 4639 | r = cxx_eval_vec_init (ctx, t, lval, |
09b42213 | 4640 | non_constant_p, overflow_p); |
4641 | break; | |
4642 | ||
09b42213 | 4643 | case VEC_PERM_EXPR: |
1227ba74 | 4644 | r = cxx_eval_trinary_expression (ctx, t, lval, |
09b42213 | 4645 | non_constant_p, overflow_p); |
4646 | break; | |
4647 | ||
941fafa5 | 4648 | case NOP_EXPR: |
4649 | if (REINTERPRET_CAST_P (t)) | |
4650 | { | |
4651 | if (!ctx->quiet) | |
d3a3cfb8 | 4652 | error_at (cp_expr_loc_or_loc (t, input_location), |
941fafa5 | 4653 | "a reinterpret_cast is not a constant expression"); |
4654 | *non_constant_p = true; | |
4655 | return t; | |
4656 | } | |
4657 | /* FALLTHROUGH. */ | |
09b42213 | 4658 | case CONVERT_EXPR: |
4659 | case VIEW_CONVERT_EXPR: | |
d2c63826 | 4660 | case UNARY_PLUS_EXPR: |
09b42213 | 4661 | { |
4662 | tree oldop = TREE_OPERAND (t, 0); | |
d2c63826 | 4663 | |
cf72f34d | 4664 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4665 | lval, |
b2a43197 | 4666 | non_constant_p, overflow_p); |
09b42213 | 4667 | if (*non_constant_p) |
4668 | return t; | |
f16ed232 | 4669 | tree type = TREE_TYPE (t); |
4670 | if (TREE_CODE (op) == PTRMEM_CST | |
4671 | && !TYPE_PTRMEM_P (type)) | |
4672 | op = cplus_expand_constant (op); | |
941fafa5 | 4673 | |
6a9b35ef | 4674 | if (TREE_CODE (op) == PTRMEM_CST && tcode == NOP_EXPR) |
4675 | { | |
941fafa5 | 4676 | if (!same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (op)) |
4677 | && !can_convert_qual (type, op)) | |
4678 | op = cplus_expand_constant (op); | |
4679 | return cp_fold_convert (type, op); | |
6a9b35ef | 4680 | } |
cb768824 | 4681 | |
d03fa520 | 4682 | if (INDIRECT_TYPE_P (type) && TREE_CODE (op) == INTEGER_CST) |
09b42213 | 4683 | { |
cb768824 | 4684 | if (integer_zerop (op)) |
4685 | { | |
90ad495b | 4686 | if (TYPE_REF_P (type)) |
cb768824 | 4687 | { |
4688 | if (!ctx->quiet) | |
d3a3cfb8 | 4689 | error_at (cp_expr_loc_or_loc (t, input_location), |
cb768824 | 4690 | "dereferencing a null pointer"); |
4691 | *non_constant_p = true; | |
4692 | return t; | |
4693 | } | |
90ad495b | 4694 | else if (TYPE_PTR_P (TREE_TYPE (op))) |
cb768824 | 4695 | { |
4696 | tree from = TREE_TYPE (op); | |
4697 | ||
4698 | if (!can_convert (type, from, tf_none)) | |
4699 | { | |
4700 | if (!ctx->quiet) | |
d3a3cfb8 | 4701 | error_at (cp_expr_loc_or_loc (t, input_location), |
cb768824 | 4702 | "conversion of %qT null pointer to %qT " |
4703 | "is not a constant expression", | |
4704 | from, type); | |
4705 | *non_constant_p = true; | |
4706 | return t; | |
4707 | } | |
4708 | } | |
4709 | } | |
4710 | else | |
4711 | { | |
4712 | /* This detects for example: | |
4713 | reinterpret_cast<void*>(sizeof 0) | |
4714 | */ | |
4715 | if (!ctx->quiet) | |
d3a3cfb8 | 4716 | error_at (cp_expr_loc_or_loc (t, input_location), |
cb768824 | 4717 | "%<reinterpret_cast<%T>(%E)%> is not " |
ea034e2c | 4718 | "a constant expression", |
cb768824 | 4719 | type, op); |
4720 | *non_constant_p = true; | |
4721 | return t; | |
4722 | } | |
09b42213 | 4723 | } |
941fafa5 | 4724 | |
d2c63826 | 4725 | if (op == oldop && tcode != UNARY_PLUS_EXPR) |
09b42213 | 4726 | /* We didn't fold at the top so we could check for ptr-int |
4727 | conversion. */ | |
4728 | return fold (t); | |
941fafa5 | 4729 | |
6b53d686 | 4730 | /* Handle an array's bounds having been deduced after we built |
4731 | the wrapping expression. */ | |
4732 | if (same_type_ignoring_tlq_and_bounds_p (type, TREE_TYPE (op))) | |
4733 | r = op; | |
4734 | else if (tcode == UNARY_PLUS_EXPR) | |
d2c63826 | 4735 | r = fold_convert (TREE_TYPE (t), op); |
4736 | else | |
4737 | r = fold_build1 (tcode, type, op); | |
941fafa5 | 4738 | |
09b42213 | 4739 | /* Conversion of an out-of-range value has implementation-defined |
4740 | behavior; the language considers it different from arithmetic | |
4741 | overflow, which is undefined. */ | |
4742 | if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op)) | |
4743 | TREE_OVERFLOW (r) = false; | |
4744 | } | |
4745 | break; | |
4746 | ||
4747 | case EMPTY_CLASS_EXPR: | |
4748 | /* This is good enough for a function argument that might not get | |
4749 | used, and they can't do anything with it, so just return it. */ | |
4750 | return t; | |
4751 | ||
9c96033c | 4752 | case STATEMENT_LIST: |
00f21715 | 4753 | new_ctx = *ctx; |
4754 | new_ctx.ctor = new_ctx.object = NULL_TREE; | |
f83e6885 | 4755 | return cxx_eval_statement_list (&new_ctx, t, |
00f21715 | 4756 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4757 | |
4758 | case BIND_EXPR: | |
4759 | return cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t), | |
1227ba74 | 4760 | lval, |
00f21715 | 4761 | non_constant_p, overflow_p, |
4762 | jump_target); | |
9c96033c | 4763 | |
09b42213 | 4764 | case PREINCREMENT_EXPR: |
4765 | case POSTINCREMENT_EXPR: | |
4766 | case PREDECREMENT_EXPR: | |
4767 | case POSTDECREMENT_EXPR: | |
f83e6885 | 4768 | return cxx_eval_increment_expression (ctx, t, |
1227ba74 | 4769 | lval, non_constant_p, overflow_p); |
9c96033c | 4770 | |
4771 | case LAMBDA_EXPR: | |
09b42213 | 4772 | case NEW_EXPR: |
4773 | case VEC_NEW_EXPR: | |
4774 | case DELETE_EXPR: | |
4775 | case VEC_DELETE_EXPR: | |
4776 | case THROW_EXPR: | |
09b42213 | 4777 | case MODOP_EXPR: |
4778 | /* GCC internal stuff. */ | |
4779 | case VA_ARG_EXPR: | |
4780 | case OBJ_TYPE_REF: | |
09b42213 | 4781 | case NON_DEPENDENT_EXPR: |
4782 | case BASELINK: | |
09b42213 | 4783 | case OFFSET_REF: |
f83e6885 | 4784 | if (!ctx->quiet) |
d3a3cfb8 | 4785 | error_at (cp_expr_loc_or_loc (t, input_location), |
ea034e2c | 4786 | "expression %qE is not a constant expression", t); |
09b42213 | 4787 | *non_constant_p = true; |
4788 | break; | |
4789 | ||
cf72f34d | 4790 | case PLACEHOLDER_EXPR: |
85de9604 | 4791 | /* Use of the value or address of the current object. */ |
4792 | if (tree ctor = lookup_placeholder (ctx, lval, TREE_TYPE (t))) | |
4793 | return cxx_eval_constant_expression (ctx, ctor, lval, | |
4794 | non_constant_p, overflow_p); | |
4795 | /* A placeholder without a referent. We can get here when | |
4796 | checking whether NSDMIs are noexcept, or in massage_init_elt; | |
4797 | just say it's non-constant for now. */ | |
4798 | gcc_assert (ctx->quiet); | |
4799 | *non_constant_p = true; | |
cf72f34d | 4800 | break; |
4801 | ||
cf03ba19 | 4802 | case EXIT_EXPR: |
4803 | { | |
4804 | tree cond = TREE_OPERAND (t, 0); | |
4805 | cond = cxx_eval_constant_expression (ctx, cond, /*lval*/false, | |
4806 | non_constant_p, overflow_p); | |
4807 | VERIFY_CONSTANT (cond); | |
4808 | if (integer_nonzerop (cond)) | |
4809 | *jump_target = t; | |
4810 | } | |
4811 | break; | |
4812 | ||
9c96033c | 4813 | case GOTO_EXPR: |
00f21715 | 4814 | *jump_target = TREE_OPERAND (t, 0); |
d29e4e8c | 4815 | gcc_assert (breaks (jump_target) || continues (jump_target) |
4816 | /* Allow for jumping to a cdtor_label. */ | |
4817 | || returns (jump_target)); | |
00f21715 | 4818 | break; |
4819 | ||
9c96033c | 4820 | case LOOP_EXPR: |
f83e6885 | 4821 | cxx_eval_loop_expr (ctx, t, |
00f21715 | 4822 | non_constant_p, overflow_p, jump_target); |
4823 | break; | |
4824 | ||
9c96033c | 4825 | case SWITCH_EXPR: |
f83e6885 | 4826 | cxx_eval_switch_expr (ctx, t, |
00f21715 | 4827 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4828 | break; |
4829 | ||
56c12fd4 | 4830 | case REQUIRES_EXPR: |
4831 | /* It's possible to get a requires-expression in a constant | |
4832 | expression. For example: | |
4833 | ||
4834 | template<typename T> concept bool C() { | |
4835 | return requires (T t) { t; }; | |
4836 | } | |
4837 | ||
4838 | template<typename T> requires !C<T>() void f(T); | |
4839 | ||
4840 | Normalization leaves f with the associated constraint | |
4841 | '!requires (T t) { ... }' which is not transformed into | |
4842 | a constraint. */ | |
4843 | if (!processing_template_decl) | |
4844 | return evaluate_constraint_expression (t, NULL_TREE); | |
4845 | else | |
4846 | *non_constant_p = true; | |
4847 | return t; | |
4848 | ||
24c6ee98 | 4849 | case ANNOTATE_EXPR: |
24c6ee98 | 4850 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
4851 | lval, | |
4852 | non_constant_p, overflow_p, | |
4853 | jump_target); | |
4854 | break; | |
4855 | ||
7285637a | 4856 | case USING_STMT: |
4857 | r = void_node; | |
4858 | break; | |
4859 | ||
09b42213 | 4860 | default: |
b9a3af23 | 4861 | if (STATEMENT_CODE_P (TREE_CODE (t))) |
4862 | { | |
4863 | /* This function doesn't know how to deal with pre-genericize | |
4864 | statements; this can only happen with statement-expressions, | |
4865 | so for now just fail. */ | |
4866 | if (!ctx->quiet) | |
4867 | error_at (EXPR_LOCATION (t), | |
ea034e2c | 4868 | "statement is not a constant expression"); |
b9a3af23 | 4869 | } |
4870 | else | |
4871 | internal_error ("unexpected expression %qE of kind %s", t, | |
4872 | get_tree_code_name (TREE_CODE (t))); | |
09b42213 | 4873 | *non_constant_p = true; |
4874 | break; | |
4875 | } | |
4876 | ||
4877 | if (r == error_mark_node) | |
4878 | *non_constant_p = true; | |
4879 | ||
4880 | if (*non_constant_p) | |
4881 | return t; | |
4882 | else | |
4883 | return r; | |
4884 | } | |
4885 | ||
6e1bbaae | 4886 | /* P0859: A function is needed for constant evaluation if it is a constexpr |
4887 | function that is named by an expression ([basic.def.odr]) that is | |
4888 | potentially constant evaluated. | |
4889 | ||
4890 | So we need to instantiate any constexpr functions mentioned by the | |
4891 | expression even if the definition isn't needed for evaluating the | |
4892 | expression. */ | |
4893 | ||
4894 | static tree | |
4895 | instantiate_cx_fn_r (tree *tp, int *walk_subtrees, void */*data*/) | |
4896 | { | |
4897 | if (TREE_CODE (*tp) == FUNCTION_DECL | |
4898 | && DECL_DECLARED_CONSTEXPR_P (*tp) | |
4899 | && !DECL_INITIAL (*tp) | |
eed138cf | 4900 | && !trivial_fn_p (*tp) |
6e1bbaae | 4901 | && DECL_TEMPLOID_INSTANTIATION (*tp)) |
4902 | { | |
4903 | ++function_depth; | |
4904 | instantiate_decl (*tp, /*defer_ok*/false, /*expl_inst*/false); | |
4905 | --function_depth; | |
4906 | } | |
4907 | else if (TREE_CODE (*tp) == CALL_EXPR | |
4908 | || TREE_CODE (*tp) == AGGR_INIT_EXPR) | |
4909 | { | |
4910 | if (EXPR_HAS_LOCATION (*tp)) | |
4911 | input_location = EXPR_LOCATION (*tp); | |
4912 | } | |
4913 | ||
4914 | if (!EXPR_P (*tp)) | |
4915 | *walk_subtrees = 0; | |
4916 | ||
4917 | return NULL_TREE; | |
4918 | } | |
4919 | static void | |
4920 | instantiate_constexpr_fns (tree t) | |
4921 | { | |
4922 | location_t loc = input_location; | |
4923 | cp_walk_tree_without_duplicates (&t, instantiate_cx_fn_r, NULL); | |
4924 | input_location = loc; | |
4925 | } | |
4926 | ||
18d371d3 | 4927 | /* ALLOW_NON_CONSTANT is false if T is required to be a constant expression. |
4928 | PRETEND_CONST_REQUIRED is true if T is required to be const-evaluated as | |
4929 | per P0595 even when ALLOW_NON_CONSTANT is true. */ | |
4930 | ||
09b42213 | 4931 | static tree |
cf72f34d | 4932 | cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, |
18d371d3 | 4933 | bool strict = true, |
4934 | bool pretend_const_required = false, | |
4935 | tree object = NULL_TREE) | |
09b42213 | 4936 | { |
c300fe28 | 4937 | auto_timevar time (TV_CONSTEXPR); |
4938 | ||
09b42213 | 4939 | bool non_constant_p = false; |
4940 | bool overflow_p = false; | |
cf72f34d | 4941 | hash_map<tree,tree> map; |
2631cb67 | 4942 | |
2a2770c6 | 4943 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, NULL, NULL, |
18d371d3 | 4944 | allow_non_constant, strict, |
4945 | pretend_const_required || !allow_non_constant }; | |
2631cb67 | 4946 | |
cf72f34d | 4947 | tree type = initialized_type (t); |
cf72f34d | 4948 | tree r = t; |
4949 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) | |
4950 | { | |
4951 | /* In C++14 an NSDMI can participate in aggregate initialization, | |
4952 | and can refer to the address of the object being initialized, so | |
4953 | we need to pass in the relevant VAR_DECL if we want to do the | |
4954 | evaluation in a single pass. The evaluation will dynamically | |
4955 | update ctx.values for the VAR_DECL. We use the same strategy | |
4956 | for C++11 constexpr constructors that refer to the object being | |
4957 | initialized. */ | |
4958 | ctx.ctor = build_constructor (type, NULL); | |
165d0d5b | 4959 | CONSTRUCTOR_NO_CLEARING (ctx.ctor) = true; |
9c96033c | 4960 | if (!object) |
4961 | { | |
4962 | if (TREE_CODE (t) == TARGET_EXPR) | |
4963 | object = TARGET_EXPR_SLOT (t); | |
4964 | else if (TREE_CODE (t) == AGGR_INIT_EXPR) | |
4965 | object = AGGR_INIT_EXPR_SLOT (t); | |
4966 | } | |
cf72f34d | 4967 | ctx.object = object; |
4968 | if (object) | |
4969 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
4970 | (type, TREE_TYPE (object))); | |
4971 | if (object && DECL_P (object)) | |
4972 | map.put (object, ctx.ctor); | |
4973 | if (TREE_CODE (r) == TARGET_EXPR) | |
4974 | /* Avoid creating another CONSTRUCTOR when we expand the | |
4975 | TARGET_EXPR. */ | |
4976 | r = TARGET_EXPR_INITIAL (r); | |
4977 | } | |
4978 | ||
6e1bbaae | 4979 | instantiate_constexpr_fns (r); |
f83e6885 | 4980 | r = cxx_eval_constant_expression (&ctx, r, |
b2a43197 | 4981 | false, &non_constant_p, &overflow_p); |
09b42213 | 4982 | |
4983 | verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); | |
4984 | ||
bbcc9042 | 4985 | /* Mutable logic is a bit tricky: we want to allow initialization of |
4986 | constexpr variables with mutable members, but we can't copy those | |
4987 | members to another constexpr variable. */ | |
4988 | if (TREE_CODE (r) == CONSTRUCTOR | |
4989 | && CONSTRUCTOR_MUTABLE_POISON (r)) | |
09b42213 | 4990 | { |
09b42213 | 4991 | if (!allow_non_constant) |
bbcc9042 | 4992 | error ("%qE is not a constant expression because it refers to " |
4993 | "mutable subobjects of %qT", t, type); | |
09b42213 | 4994 | non_constant_p = true; |
4995 | } | |
4996 | ||
c6d97004 | 4997 | if (TREE_CODE (r) == CONSTRUCTOR |
165d0d5b | 4998 | && CONSTRUCTOR_NO_CLEARING (r)) |
c6d97004 | 4999 | { |
5000 | if (!allow_non_constant) | |
5001 | error ("%qE is not a constant expression because it refers to " | |
5002 | "an incompletely initialized variable", t); | |
5003 | TREE_CONSTANT (r) = false; | |
5004 | non_constant_p = true; | |
5005 | } | |
5006 | ||
09b42213 | 5007 | /* Technically we should check this for all subexpressions, but that |
5008 | runs into problems with our internal representation of pointer | |
5009 | subtraction and the 5.19 rules are still in flux. */ | |
5010 | if (CONVERT_EXPR_CODE_P (TREE_CODE (r)) | |
5011 | && ARITHMETIC_TYPE_P (TREE_TYPE (r)) | |
5012 | && TREE_CODE (TREE_OPERAND (r, 0)) == ADDR_EXPR) | |
5013 | { | |
5014 | if (!allow_non_constant) | |
5015 | error ("conversion from pointer type %qT " | |
ea034e2c | 5016 | "to arithmetic type %qT in a constant expression", |
09b42213 | 5017 | TREE_TYPE (TREE_OPERAND (r, 0)), TREE_TYPE (r)); |
5018 | non_constant_p = true; | |
5019 | } | |
5020 | ||
5021 | if (!non_constant_p && overflow_p) | |
5022 | non_constant_p = true; | |
5023 | ||
c6c0523b | 5024 | /* Unshare the result unless it's a CONSTRUCTOR in which case it's already |
5025 | unshared. */ | |
5026 | bool should_unshare = true; | |
5027 | if (r == t || TREE_CODE (r) == CONSTRUCTOR) | |
5028 | should_unshare = false; | |
5029 | ||
09b42213 | 5030 | if (non_constant_p && !allow_non_constant) |
5031 | return error_mark_node; | |
5032 | else if (non_constant_p && TREE_CONSTANT (r)) | |
5033 | { | |
18d371d3 | 5034 | /* If __builtin_is_constant_evaluated () was evaluated to true |
5035 | and the result is not a valid constant expression, we need to | |
5036 | punt. */ | |
5037 | if (pretend_const_required) | |
5038 | return cxx_eval_outermost_constant_expr (t, true, strict, | |
5039 | false, object); | |
1d29f4ea | 5040 | /* This isn't actually constant, so unset TREE_CONSTANT. |
5041 | Don't clear TREE_CONSTANT on ADDR_EXPR, as the middle-end requires | |
5042 | it to be set if it is invariant address, even when it is not | |
5043 | a valid C++ constant expression. Wrap it with a NOP_EXPR | |
5044 | instead. */ | |
5045 | if (EXPR_P (r) && TREE_CODE (r) != ADDR_EXPR) | |
09b42213 | 5046 | r = copy_node (r); |
5047 | else if (TREE_CODE (r) == CONSTRUCTOR) | |
5048 | r = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (r), r); | |
5049 | else | |
5050 | r = build_nop (TREE_TYPE (r), r); | |
5051 | TREE_CONSTANT (r) = false; | |
5052 | } | |
5053 | else if (non_constant_p || r == t) | |
5054 | return t; | |
5055 | ||
c6c0523b | 5056 | if (should_unshare) |
5057 | r = unshare_expr (r); | |
5058 | ||
09b42213 | 5059 | if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r))) |
5060 | { | |
5061 | if (TREE_CODE (t) == TARGET_EXPR | |
5062 | && TARGET_EXPR_INITIAL (t) == r) | |
5063 | return t; | |
5064 | else | |
5065 | { | |
5066 | r = get_target_expr (r); | |
5067 | TREE_CONSTANT (r) = true; | |
5068 | return r; | |
5069 | } | |
5070 | } | |
5071 | else | |
5072 | return r; | |
5073 | } | |
5074 | ||
5075 | /* Returns true if T is a valid subexpression of a constant expression, | |
5076 | even if it isn't itself a constant expression. */ | |
5077 | ||
5078 | bool | |
5079 | is_sub_constant_expr (tree t) | |
5080 | { | |
5081 | bool non_constant_p = false; | |
5082 | bool overflow_p = false; | |
cf72f34d | 5083 | hash_map <tree, tree> map; |
2631cb67 | 5084 | |
18d371d3 | 5085 | constexpr_ctx ctx |
5086 | = { NULL, &map, NULL, NULL, NULL, NULL, true, true, false }; | |
2631cb67 | 5087 | |
6e1bbaae | 5088 | instantiate_constexpr_fns (t); |
f83e6885 | 5089 | cxx_eval_constant_expression (&ctx, t, false, &non_constant_p, |
b2a43197 | 5090 | &overflow_p); |
09b42213 | 5091 | return !non_constant_p && !overflow_p; |
5092 | } | |
5093 | ||
5094 | /* If T represents a constant expression returns its reduced value. | |
5095 | Otherwise return error_mark_node. If T is dependent, then | |
5096 | return NULL. */ | |
5097 | ||
5098 | tree | |
cf72f34d | 5099 | cxx_constant_value (tree t, tree decl) |
09b42213 | 5100 | { |
18d371d3 | 5101 | return cxx_eval_outermost_constant_expr (t, false, true, true, decl); |
09b42213 | 5102 | } |
5103 | ||
d2c63826 | 5104 | /* Helper routine for fold_simple function. Either return simplified |
5105 | expression T, otherwise NULL_TREE. | |
5106 | In contrast to cp_fully_fold, and to maybe_constant_value, we try to fold | |
5107 | even if we are within template-declaration. So be careful on call, as in | |
5108 | such case types can be undefined. */ | |
5109 | ||
5110 | static tree | |
5111 | fold_simple_1 (tree t) | |
5112 | { | |
5113 | tree op1; | |
5114 | enum tree_code code = TREE_CODE (t); | |
5115 | ||
5116 | switch (code) | |
5117 | { | |
5118 | case INTEGER_CST: | |
5119 | case REAL_CST: | |
5120 | case VECTOR_CST: | |
5121 | case FIXED_CST: | |
5122 | case COMPLEX_CST: | |
5123 | return t; | |
5124 | ||
5125 | case SIZEOF_EXPR: | |
5126 | return fold_sizeof_expr (t); | |
5127 | ||
5128 | case ABS_EXPR: | |
19b4138e | 5129 | case ABSU_EXPR: |
d2c63826 | 5130 | case CONJ_EXPR: |
5131 | case REALPART_EXPR: | |
5132 | case IMAGPART_EXPR: | |
5133 | case NEGATE_EXPR: | |
5134 | case BIT_NOT_EXPR: | |
5135 | case TRUTH_NOT_EXPR: | |
5136 | case NOP_EXPR: | |
5137 | case VIEW_CONVERT_EXPR: | |
5138 | case CONVERT_EXPR: | |
5139 | case FLOAT_EXPR: | |
5140 | case FIX_TRUNC_EXPR: | |
5141 | case FIXED_CONVERT_EXPR: | |
5142 | case ADDR_SPACE_CONVERT_EXPR: | |
5143 | ||
5144 | op1 = TREE_OPERAND (t, 0); | |
5145 | ||
5146 | t = const_unop (code, TREE_TYPE (t), op1); | |
5147 | if (!t) | |
5148 | return NULL_TREE; | |
5149 | ||
5150 | if (CONVERT_EXPR_CODE_P (code) | |
5151 | && TREE_OVERFLOW_P (t) && !TREE_OVERFLOW_P (op1)) | |
5152 | TREE_OVERFLOW (t) = false; | |
5153 | return t; | |
5154 | ||
5155 | default: | |
5156 | return NULL_TREE; | |
5157 | } | |
5158 | } | |
5159 | ||
5160 | /* If T is a simple constant expression, returns its simplified value. | |
6fe5fea9 | 5161 | Otherwise returns T. In contrast to maybe_constant_value we |
d2c63826 | 5162 | simplify only few operations on constant-expressions, and we don't |
5163 | try to simplify constexpressions. */ | |
5164 | ||
5165 | tree | |
5166 | fold_simple (tree t) | |
5167 | { | |
d2c63826 | 5168 | if (processing_template_decl) |
5169 | return t; | |
5170 | ||
6fe5fea9 | 5171 | tree r = fold_simple_1 (t); |
5172 | if (r) | |
5173 | return r; | |
d2c63826 | 5174 | |
6fe5fea9 | 5175 | return t; |
d2c63826 | 5176 | } |
5177 | ||
09b42213 | 5178 | /* If T is a constant expression, returns its reduced value. |
5179 | Otherwise, if T does not have TREE_CONSTANT set, returns T. | |
5180 | Otherwise, returns a version of T without TREE_CONSTANT. */ | |
5181 | ||
b601ad30 | 5182 | static GTY((deletable)) hash_map<tree, tree> *cv_cache; |
5183 | ||
5184 | tree | |
5185 | maybe_constant_value (tree t, tree decl) | |
09b42213 | 5186 | { |
5187 | tree r; | |
5188 | ||
7e1f8be4 | 5189 | if (!is_nondependent_constant_expression (t)) |
09b42213 | 5190 | { |
5191 | if (TREE_OVERFLOW_P (t)) | |
5192 | { | |
5193 | t = build_nop (TREE_TYPE (t), t); | |
5194 | TREE_CONSTANT (t) = false; | |
5195 | } | |
5196 | return t; | |
5197 | } | |
b601ad30 | 5198 | else if (CONSTANT_CLASS_P (t)) |
5199 | /* No caching or evaluation needed. */ | |
5200 | return t; | |
5201 | ||
5202 | if (cv_cache == NULL) | |
5203 | cv_cache = hash_map<tree, tree>::create_ggc (101); | |
5204 | if (tree *cached = cv_cache->get (t)) | |
5205 | return *cached; | |
09b42213 | 5206 | |
18d371d3 | 5207 | r = cxx_eval_outermost_constant_expr (t, true, true, false, decl); |
5e8689fb | 5208 | gcc_checking_assert (r == t |
5209 | || CONVERT_EXPR_P (t) | |
5210 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
5211 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
5212 | || !cp_tree_equal (r, t)); | |
b601ad30 | 5213 | cv_cache->put (t, r); |
09b42213 | 5214 | return r; |
5215 | } | |
5216 | ||
2a655a4c | 5217 | /* Dispose of the whole CV_CACHE. */ |
5218 | ||
5219 | static void | |
5220 | clear_cv_cache (void) | |
5221 | { | |
5222 | if (cv_cache != NULL) | |
5223 | cv_cache->empty (); | |
5224 | } | |
5225 | ||
f553d9f8 | 5226 | /* Dispose of the whole CV_CACHE and FOLD_CACHE. */ |
a0c919f7 | 5227 | |
5228 | void | |
f553d9f8 | 5229 | clear_cv_and_fold_caches (void) |
a0c919f7 | 5230 | { |
2a655a4c | 5231 | clear_cv_cache (); |
f553d9f8 | 5232 | clear_fold_cache (); |
a0c919f7 | 5233 | } |
5234 | ||
21131a05 | 5235 | /* Like maybe_constant_value but first fully instantiate the argument. |
5236 | ||
5237 | Note: this is equivalent to instantiate_non_dependent_expr_sfinae | |
006b503a | 5238 | (t, complain) followed by maybe_constant_value but is more efficient, |
5239 | because it calls instantiation_dependent_expression_p and | |
5240 | potential_constant_expression at most once. | |
5241 | ||
5242 | Callers should generally pass their active complain, or if they are in a | |
5243 | non-template, diagnosing context, they can use the default of | |
5244 | tf_warning_or_error. Callers that might be within a template context, don't | |
5245 | have a complain parameter, and aren't going to remember the result for long | |
5246 | (e.g. null_ptr_cst_p), can pass tf_none and deal with error_mark_node | |
5247 | appropriately. */ | |
21131a05 | 5248 | |
5249 | tree | |
006b503a | 5250 | fold_non_dependent_expr (tree t, |
5251 | tsubst_flags_t complain /* = tf_warning_or_error */) | |
21131a05 | 5252 | { |
5253 | if (t == NULL_TREE) | |
5254 | return NULL_TREE; | |
5255 | ||
5256 | /* If we're in a template, but T isn't value dependent, simplify | |
5257 | it. We're supposed to treat: | |
5258 | ||
5259 | template <typename T> void f(T[1 + 1]); | |
5260 | template <typename T> void f(T[2]); | |
5261 | ||
5262 | as two declarations of the same function, for example. */ | |
5263 | if (processing_template_decl) | |
5264 | { | |
7e1f8be4 | 5265 | if (is_nondependent_constant_expression (t)) |
21131a05 | 5266 | { |
c8a9f04c | 5267 | processing_template_decl_sentinel s; |
006b503a | 5268 | t = instantiate_non_dependent_expr_internal (t, complain); |
21131a05 | 5269 | |
5270 | if (type_unknown_p (t) | |
5271 | || BRACE_ENCLOSED_INITIALIZER_P (t)) | |
5272 | { | |
5273 | if (TREE_OVERFLOW_P (t)) | |
5274 | { | |
5275 | t = build_nop (TREE_TYPE (t), t); | |
5276 | TREE_CONSTANT (t) = false; | |
5277 | } | |
5278 | return t; | |
5279 | } | |
5280 | ||
18d371d3 | 5281 | tree r = cxx_eval_outermost_constant_expr (t, true, true, false, |
5282 | NULL_TREE); | |
21131a05 | 5283 | /* cp_tree_equal looks through NOPs, so allow them. */ |
5e8689fb | 5284 | gcc_checking_assert (r == t |
5285 | || CONVERT_EXPR_P (t) | |
5286 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
5287 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
5288 | || !cp_tree_equal (r, t)); | |
21131a05 | 5289 | return r; |
5290 | } | |
5291 | else if (TREE_OVERFLOW_P (t)) | |
5292 | { | |
5293 | t = build_nop (TREE_TYPE (t), t); | |
5294 | TREE_CONSTANT (t) = false; | |
5295 | } | |
5296 | return t; | |
5297 | } | |
5298 | ||
5299 | return maybe_constant_value (t); | |
5300 | } | |
5301 | ||
09b42213 | 5302 | /* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather |
18d371d3 | 5303 | than wrapped in a TARGET_EXPR. |
5304 | ALLOW_NON_CONSTANT is false if T is required to be a constant expression. | |
5305 | PRETEND_CONST_REQUIRED is true if T is required to be const-evaluated as | |
5306 | per P0595 even when ALLOW_NON_CONSTANT is true. */ | |
09b42213 | 5307 | |
0c703e14 | 5308 | static tree |
18d371d3 | 5309 | maybe_constant_init_1 (tree t, tree decl, bool allow_non_constant, |
5310 | bool pretend_const_required) | |
09b42213 | 5311 | { |
d2c63826 | 5312 | if (!t) |
5313 | return t; | |
09b42213 | 5314 | if (TREE_CODE (t) == EXPR_STMT) |
5315 | t = TREE_OPERAND (t, 0); | |
5316 | if (TREE_CODE (t) == CONVERT_EXPR | |
5317 | && VOID_TYPE_P (TREE_TYPE (t))) | |
5318 | t = TREE_OPERAND (t, 0); | |
9c96033c | 5319 | if (TREE_CODE (t) == INIT_EXPR) |
5320 | t = TREE_OPERAND (t, 1); | |
c6d97004 | 5321 | if (TREE_CODE (t) == TARGET_EXPR) |
5322 | t = TARGET_EXPR_INITIAL (t); | |
7e1f8be4 | 5323 | if (!is_nondependent_static_init_expression (t)) |
2055d27a | 5324 | /* Don't try to evaluate it. */; |
0c703e14 | 5325 | else if (CONSTANT_CLASS_P (t) && allow_non_constant) |
b601ad30 | 5326 | /* No evaluation needed. */; |
2055d27a | 5327 | else |
18d371d3 | 5328 | t = cxx_eval_outermost_constant_expr (t, allow_non_constant, |
5329 | !allow_non_constant, | |
5330 | pretend_const_required, decl); | |
09b42213 | 5331 | if (TREE_CODE (t) == TARGET_EXPR) |
5332 | { | |
5333 | tree init = TARGET_EXPR_INITIAL (t); | |
5334 | if (TREE_CODE (init) == CONSTRUCTOR) | |
5335 | t = init; | |
5336 | } | |
5337 | return t; | |
5338 | } | |
5339 | ||
0c703e14 | 5340 | /* Wrapper for maybe_constant_init_1 which permits non constants. */ |
5341 | ||
5342 | tree | |
18d371d3 | 5343 | maybe_constant_init (tree t, tree decl, bool pretend_const_required) |
0c703e14 | 5344 | { |
18d371d3 | 5345 | return maybe_constant_init_1 (t, decl, true, pretend_const_required); |
0c703e14 | 5346 | } |
5347 | ||
5348 | /* Wrapper for maybe_constant_init_1 which does not permit non constants. */ | |
5349 | ||
5350 | tree | |
5351 | cxx_constant_init (tree t, tree decl) | |
5352 | { | |
18d371d3 | 5353 | return maybe_constant_init_1 (t, decl, false, true); |
0c703e14 | 5354 | } |
5355 | ||
09b42213 | 5356 | #if 0 |
5357 | /* FIXME see ADDR_EXPR section in potential_constant_expression_1. */ | |
5358 | /* Return true if the object referred to by REF has automatic or thread | |
5359 | local storage. */ | |
5360 | ||
5361 | enum { ck_ok, ck_bad, ck_unknown }; | |
5362 | static int | |
5363 | check_automatic_or_tls (tree ref) | |
5364 | { | |
3754d046 | 5365 | machine_mode mode; |
81bc0f0f | 5366 | poly_int64 bitsize, bitpos; |
09b42213 | 5367 | tree offset; |
5368 | int volatilep = 0, unsignedp = 0; | |
5369 | tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset, | |
5370 | &mode, &unsignedp, &volatilep, false); | |
5371 | duration_kind dk; | |
5372 | ||
5373 | /* If there isn't a decl in the middle, we don't know the linkage here, | |
5374 | and this isn't a constant expression anyway. */ | |
5375 | if (!DECL_P (decl)) | |
5376 | return ck_unknown; | |
5377 | dk = decl_storage_duration (decl); | |
5378 | return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok; | |
5379 | } | |
5380 | #endif | |
5381 | ||
5382 | /* Return true if T denotes a potentially constant expression. Issue | |
5383 | diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true, | |
7e1f8be4 | 5384 | an lvalue-rvalue conversion is implied. If NOW is true, we want to |
5385 | consider the expression in the current context, independent of constexpr | |
5386 | substitution. | |
09b42213 | 5387 | |
5388 | C++0x [expr.const] used to say | |
5389 | ||
5390 | 6 An expression is a potential constant expression if it is | |
5391 | a constant expression where all occurrences of function | |
5392 | parameters are replaced by arbitrary constant expressions | |
5393 | of the appropriate type. | |
5394 | ||
5395 | 2 A conditional expression is a constant expression unless it | |
5396 | involves one of the following as a potentially evaluated | |
5397 | subexpression (3.2), but subexpressions of logical AND (5.14), | |
5398 | logical OR (5.15), and conditional (5.16) operations that are | |
5399 | not evaluated are not considered. */ | |
5400 | ||
5401 | static bool | |
7e1f8be4 | 5402 | potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, |
2055d27a | 5403 | tsubst_flags_t flags) |
09b42213 | 5404 | { |
7e1f8be4 | 5405 | #define RECUR(T,RV) \ |
5406 | potential_constant_expression_1 ((T), (RV), strict, now, flags) | |
5407 | ||
09b42213 | 5408 | enum { any = false, rval = true }; |
5409 | int i; | |
5410 | tree tmp; | |
5411 | ||
5412 | if (t == error_mark_node) | |
5413 | return false; | |
5414 | if (t == NULL_TREE) | |
5415 | return true; | |
d3a3cfb8 | 5416 | location_t loc = cp_expr_loc_or_loc (t, input_location); |
eade0940 | 5417 | if (TREE_THIS_VOLATILE (t) && !DECL_P (t)) |
09b42213 | 5418 | { |
5419 | if (flags & tf_error) | |
d6a08f5c | 5420 | error_at (loc, "expression %qE has side-effects", t); |
09b42213 | 5421 | return false; |
5422 | } | |
5423 | if (CONSTANT_CLASS_P (t)) | |
5424 | return true; | |
c7282bf2 | 5425 | if (CODE_CONTAINS_STRUCT (TREE_CODE (t), TS_TYPED) |
5426 | && TREE_TYPE (t) == error_mark_node) | |
5427 | return false; | |
09b42213 | 5428 | |
5429 | switch (TREE_CODE (t)) | |
5430 | { | |
5431 | case FUNCTION_DECL: | |
5432 | case BASELINK: | |
5433 | case TEMPLATE_DECL: | |
5434 | case OVERLOAD: | |
5435 | case TEMPLATE_ID_EXPR: | |
5436 | case LABEL_DECL: | |
5437 | case LABEL_EXPR: | |
9c96033c | 5438 | case CASE_LABEL_EXPR: |
09b42213 | 5439 | case CONST_DECL: |
5440 | case SIZEOF_EXPR: | |
5441 | case ALIGNOF_EXPR: | |
5442 | case OFFSETOF_EXPR: | |
5443 | case NOEXCEPT_EXPR: | |
5444 | case TEMPLATE_PARM_INDEX: | |
5445 | case TRAIT_EXPR: | |
5446 | case IDENTIFIER_NODE: | |
5447 | case USERDEF_LITERAL: | |
5448 | /* We can see a FIELD_DECL in a pointer-to-member expression. */ | |
5449 | case FIELD_DECL: | |
d2c63826 | 5450 | case RESULT_DECL: |
09b42213 | 5451 | case USING_DECL: |
9c96033c | 5452 | case USING_STMT: |
cf72f34d | 5453 | case PLACEHOLDER_EXPR: |
9c96033c | 5454 | case BREAK_STMT: |
5455 | case CONTINUE_STMT: | |
56c12fd4 | 5456 | case REQUIRES_EXPR: |
33603066 | 5457 | case STATIC_ASSERT: |
90567983 | 5458 | case DEBUG_BEGIN_STMT: |
09b42213 | 5459 | return true; |
5460 | ||
7e1f8be4 | 5461 | case PARM_DECL: |
5462 | if (now) | |
5463 | { | |
5464 | if (flags & tf_error) | |
5465 | error ("%qE is not a constant expression", t); | |
5466 | return false; | |
5467 | } | |
5468 | return true; | |
5469 | ||
09b42213 | 5470 | case AGGR_INIT_EXPR: |
5471 | case CALL_EXPR: | |
5472 | /* -- an invocation of a function other than a constexpr function | |
5473 | or a constexpr constructor. */ | |
5474 | { | |
5475 | tree fun = get_function_named_in_call (t); | |
5476 | const int nargs = call_expr_nargs (t); | |
5477 | i = 0; | |
5478 | ||
9c96033c | 5479 | if (fun == NULL_TREE) |
5480 | { | |
732905bb | 5481 | /* Reset to allow the function to continue past the end |
5482 | of the block below. Otherwise return early. */ | |
5483 | bool bail = true; | |
5484 | ||
32cf7025 | 5485 | if (TREE_CODE (t) == CALL_EXPR |
5486 | && CALL_EXPR_FN (t) == NULL_TREE) | |
5487 | switch (CALL_EXPR_IFN (t)) | |
5488 | { | |
5489 | /* These should be ignored, they are optimized away from | |
5490 | constexpr functions. */ | |
5491 | case IFN_UBSAN_NULL: | |
5492 | case IFN_UBSAN_BOUNDS: | |
5493 | case IFN_UBSAN_VPTR: | |
3c77f69c | 5494 | case IFN_FALLTHROUGH: |
32cf7025 | 5495 | return true; |
732905bb | 5496 | |
5497 | case IFN_ADD_OVERFLOW: | |
5498 | case IFN_SUB_OVERFLOW: | |
5499 | case IFN_MUL_OVERFLOW: | |
6e1b2ffb | 5500 | case IFN_LAUNDER: |
732905bb | 5501 | bail = false; |
5502 | ||
32cf7025 | 5503 | default: |
5504 | break; | |
5505 | } | |
732905bb | 5506 | |
5507 | if (bail) | |
5508 | { | |
5509 | /* fold_call_expr can't do anything with IFN calls. */ | |
5510 | if (flags & tf_error) | |
d6a08f5c | 5511 | error_at (loc, "call to internal function %qE", t); |
732905bb | 5512 | return false; |
5513 | } | |
9c96033c | 5514 | } |
732905bb | 5515 | |
5516 | if (fun && is_overloaded_fn (fun)) | |
09b42213 | 5517 | { |
5518 | if (TREE_CODE (fun) == FUNCTION_DECL) | |
5519 | { | |
5520 | if (builtin_valid_in_constant_expr_p (fun)) | |
5521 | return true; | |
5522 | if (!DECL_DECLARED_CONSTEXPR_P (fun) | |
5523 | /* Allow any built-in function; if the expansion | |
5524 | isn't constant, we'll deal with that then. */ | |
5525 | && !is_builtin_fn (fun)) | |
5526 | { | |
5527 | if (flags & tf_error) | |
5528 | { | |
5967b28b | 5529 | error_at (loc, "call to non-%<constexpr%> function %qD", |
d6a08f5c | 5530 | fun); |
09b42213 | 5531 | explain_invalid_constexpr_fn (fun); |
5532 | } | |
5533 | return false; | |
5534 | } | |
5535 | /* A call to a non-static member function takes the address | |
5536 | of the object as the first argument. But in a constant | |
5537 | expression the address will be folded away, so look | |
5538 | through it now. */ | |
5539 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
5540 | && !DECL_CONSTRUCTOR_P (fun)) | |
5541 | { | |
5542 | tree x = get_nth_callarg (t, 0); | |
5543 | if (is_this_parameter (x)) | |
cf72f34d | 5544 | return true; |
7e1f8be4 | 5545 | /* Don't require an immediately constant value, as |
5546 | constexpr substitution might not use the value. */ | |
5547 | bool sub_now = false; | |
5548 | if (!potential_constant_expression_1 (x, rval, strict, | |
5549 | sub_now, flags)) | |
09b42213 | 5550 | return false; |
5551 | i = 1; | |
5552 | } | |
5553 | } | |
5554 | else | |
5555 | { | |
2055d27a | 5556 | if (!RECUR (fun, true)) |
09b42213 | 5557 | return false; |
5558 | fun = get_first_fn (fun); | |
5559 | } | |
5560 | /* Skip initial arguments to base constructors. */ | |
5561 | if (DECL_BASE_CONSTRUCTOR_P (fun)) | |
5562 | i = num_artificial_parms_for (fun); | |
5563 | fun = DECL_ORIGIN (fun); | |
5564 | } | |
732905bb | 5565 | else if (fun) |
09b42213 | 5566 | { |
2055d27a | 5567 | if (RECUR (fun, rval)) |
09b42213 | 5568 | /* Might end up being a constant function pointer. */; |
5569 | else | |
5570 | return false; | |
5571 | } | |
5572 | for (; i < nargs; ++i) | |
5573 | { | |
5574 | tree x = get_nth_callarg (t, i); | |
b2742b58 | 5575 | /* In a template, reference arguments haven't been converted to |
5576 | REFERENCE_TYPE and we might not even know if the parameter | |
5577 | is a reference, so accept lvalue constants too. */ | |
5578 | bool rv = processing_template_decl ? any : rval; | |
7e1f8be4 | 5579 | /* Don't require an immediately constant value, as constexpr |
5580 | substitution might not use the value of the argument. */ | |
5581 | bool sub_now = false; | |
5582 | if (!potential_constant_expression_1 (x, rv, strict, | |
5583 | sub_now, flags)) | |
09b42213 | 5584 | return false; |
5585 | } | |
5586 | return true; | |
5587 | } | |
5588 | ||
5589 | case NON_LVALUE_EXPR: | |
5590 | /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to | |
5591 | -- an lvalue of integral type that refers to a non-volatile | |
5592 | const variable or static data member initialized with | |
5593 | constant expressions, or | |
5594 | ||
5595 | -- an lvalue of literal type that refers to non-volatile | |
5596 | object defined with constexpr, or that refers to a | |
5597 | sub-object of such an object; */ | |
2055d27a | 5598 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 5599 | |
5600 | case VAR_DECL: | |
9c8aeb66 | 5601 | if (DECL_HAS_VALUE_EXPR_P (t)) |
297de7bc | 5602 | { |
d0e2b7e7 | 5603 | if (now && is_normal_capture_proxy (t)) |
297de7bc | 5604 | { |
5605 | /* -- in a lambda-expression, a reference to this or to a | |
5606 | variable with automatic storage duration defined outside that | |
5607 | lambda-expression, where the reference would be an | |
5608 | odr-use. */ | |
5609 | if (flags & tf_error) | |
5610 | { | |
5611 | tree cap = DECL_CAPTURED_VARIABLE (t); | |
5612 | error ("lambda capture of %qE is not a constant expression", | |
5613 | cap); | |
5614 | if (!want_rval && decl_constant_var_p (cap)) | |
5615 | inform (input_location, "because it is used as a glvalue"); | |
5616 | } | |
5617 | return false; | |
5618 | } | |
5619 | return RECUR (DECL_VALUE_EXPR (t), rval); | |
5620 | } | |
2055d27a | 5621 | if (want_rval |
33603066 | 5622 | && !var_in_maybe_constexpr_fn (t) |
c7282bf2 | 5623 | && !type_dependent_expression_p (t) |
8d6486e1 | 5624 | && !decl_maybe_constant_var_p (t) |
2055d27a | 5625 | && (strict |
5626 | || !CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (t)) | |
8d6486e1 | 5627 | || (DECL_INITIAL (t) |
5628 | && !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (t))) | |
c7282bf2 | 5629 | && COMPLETE_TYPE_P (TREE_TYPE (t)) |
5630 | && !is_really_empty_class (TREE_TYPE (t))) | |
09b42213 | 5631 | { |
5632 | if (flags & tf_error) | |
5633 | non_const_var_error (t); | |
5634 | return false; | |
5635 | } | |
5636 | return true; | |
5637 | ||
5638 | case NOP_EXPR: | |
5639 | case CONVERT_EXPR: | |
5640 | case VIEW_CONVERT_EXPR: | |
5641 | /* -- a reinterpret_cast. FIXME not implemented, and this rule | |
5642 | may change to something more specific to type-punning (DR 1312). */ | |
5643 | { | |
5644 | tree from = TREE_OPERAND (t, 0); | |
d03fa520 | 5645 | if (INDIRECT_TYPE_P (TREE_TYPE (t)) |
09b42213 | 5646 | && TREE_CODE (from) == INTEGER_CST |
5647 | && !integer_zerop (from)) | |
5648 | { | |
5649 | if (flags & tf_error) | |
d6a08f5c | 5650 | error_at (loc, "reinterpret_cast from integer to pointer"); |
09b42213 | 5651 | return false; |
5652 | } | |
2055d27a | 5653 | return (RECUR (from, TREE_CODE (t) != VIEW_CONVERT_EXPR)); |
09b42213 | 5654 | } |
5655 | ||
cd45162d | 5656 | case ADDRESSOF_EXPR: |
5657 | /* This is like ADDR_EXPR, except it won't form pointer-to-member. */ | |
5658 | t = TREE_OPERAND (t, 0); | |
5659 | goto handle_addr_expr; | |
5660 | ||
09b42213 | 5661 | case ADDR_EXPR: |
5662 | /* -- a unary operator & that is applied to an lvalue that | |
5663 | designates an object with thread or automatic storage | |
5664 | duration; */ | |
5665 | t = TREE_OPERAND (t, 0); | |
5666 | ||
5667 | if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t)) | |
5668 | /* A pointer-to-member constant. */ | |
5669 | return true; | |
5670 | ||
cd45162d | 5671 | handle_addr_expr: |
09b42213 | 5672 | #if 0 |
5673 | /* FIXME adjust when issue 1197 is fully resolved. For now don't do | |
5674 | any checking here, as we might dereference the pointer later. If | |
5675 | we remove this code, also remove check_automatic_or_tls. */ | |
5676 | i = check_automatic_or_tls (t); | |
5677 | if (i == ck_ok) | |
5678 | return true; | |
5679 | if (i == ck_bad) | |
5680 | { | |
5681 | if (flags & tf_error) | |
5682 | error ("address-of an object %qE with thread local or " | |
5683 | "automatic storage is not a constant expression", t); | |
5684 | return false; | |
5685 | } | |
5686 | #endif | |
2055d27a | 5687 | return RECUR (t, any); |
09b42213 | 5688 | |
20b34a56 | 5689 | case REALPART_EXPR: |
5690 | case IMAGPART_EXPR: | |
09b42213 | 5691 | case COMPONENT_REF: |
5692 | case BIT_FIELD_REF: | |
5693 | case ARROW_EXPR: | |
5694 | case OFFSET_REF: | |
5695 | /* -- a class member access unless its postfix-expression is | |
5696 | of literal type or of pointer to literal type. */ | |
5697 | /* This test would be redundant, as it follows from the | |
5698 | postfix-expression being a potential constant expression. */ | |
eade0940 | 5699 | if (type_unknown_p (t)) |
5700 | return true; | |
2055d27a | 5701 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5702 | |
5703 | case EXPR_PACK_EXPANSION: | |
2055d27a | 5704 | return RECUR (PACK_EXPANSION_PATTERN (t), want_rval); |
09b42213 | 5705 | |
5706 | case INDIRECT_REF: | |
5707 | { | |
5708 | tree x = TREE_OPERAND (t, 0); | |
5709 | STRIP_NOPS (x); | |
997bbf70 | 5710 | if (is_this_parameter (x) && !is_capture_proxy (x)) |
09b42213 | 5711 | { |
b7e4a558 | 5712 | if (!var_in_maybe_constexpr_fn (x)) |
09b42213 | 5713 | { |
5714 | if (flags & tf_error) | |
d6a08f5c | 5715 | error_at (loc, "use of %<this%> in a constant expression"); |
09b42213 | 5716 | return false; |
5717 | } | |
09b42213 | 5718 | return true; |
5719 | } | |
2055d27a | 5720 | return RECUR (x, rval); |
09b42213 | 5721 | } |
5722 | ||
9c96033c | 5723 | case STATEMENT_LIST: |
5724 | { | |
5725 | tree_stmt_iterator i; | |
5726 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
5727 | { | |
2055d27a | 5728 | if (!RECUR (tsi_stmt (i), any)) |
9c96033c | 5729 | return false; |
5730 | } | |
5731 | return true; | |
5732 | } | |
5733 | break; | |
5734 | ||
5735 | case MODIFY_EXPR: | |
5736 | if (cxx_dialect < cxx14) | |
5737 | goto fail; | |
2055d27a | 5738 | if (!RECUR (TREE_OPERAND (t, 0), any)) |
9c96033c | 5739 | return false; |
2055d27a | 5740 | if (!RECUR (TREE_OPERAND (t, 1), rval)) |
9c96033c | 5741 | return false; |
5742 | return true; | |
5743 | ||
5744 | case MODOP_EXPR: | |
5745 | if (cxx_dialect < cxx14) | |
5746 | goto fail; | |
2055d27a | 5747 | if (!RECUR (TREE_OPERAND (t, 0), rval)) |
9c96033c | 5748 | return false; |
2055d27a | 5749 | if (!RECUR (TREE_OPERAND (t, 2), rval)) |
9c96033c | 5750 | return false; |
5751 | return true; | |
5752 | ||
9c96033c | 5753 | case DO_STMT: |
2055d27a | 5754 | if (!RECUR (DO_COND (t), rval)) |
9c96033c | 5755 | return false; |
2055d27a | 5756 | if (!RECUR (DO_BODY (t), any)) |
9c96033c | 5757 | return false; |
5758 | return true; | |
5759 | ||
5760 | case FOR_STMT: | |
2055d27a | 5761 | if (!RECUR (FOR_INIT_STMT (t), any)) |
9c96033c | 5762 | return false; |
2055d27a | 5763 | if (!RECUR (FOR_COND (t), rval)) |
9c96033c | 5764 | return false; |
2055d27a | 5765 | if (!RECUR (FOR_EXPR (t), any)) |
9c96033c | 5766 | return false; |
2055d27a | 5767 | if (!RECUR (FOR_BODY (t), any)) |
9c96033c | 5768 | return false; |
5769 | return true; | |
5770 | ||
33603066 | 5771 | case RANGE_FOR_STMT: |
5772 | if (!RECUR (RANGE_FOR_EXPR (t), any)) | |
5773 | return false; | |
5774 | if (!RECUR (RANGE_FOR_BODY (t), any)) | |
5775 | return false; | |
5776 | return true; | |
5777 | ||
9c96033c | 5778 | case WHILE_STMT: |
2055d27a | 5779 | if (!RECUR (WHILE_COND (t), rval)) |
9c96033c | 5780 | return false; |
2055d27a | 5781 | if (!RECUR (WHILE_BODY (t), any)) |
9c96033c | 5782 | return false; |
5783 | return true; | |
5784 | ||
5785 | case SWITCH_STMT: | |
2055d27a | 5786 | if (!RECUR (SWITCH_STMT_COND (t), rval)) |
9c96033c | 5787 | return false; |
748c426a | 5788 | /* FIXME we don't check SWITCH_STMT_BODY currently, because even |
5789 | unreachable labels would be checked. */ | |
9c96033c | 5790 | return true; |
5791 | ||
da7981e0 | 5792 | case STMT_EXPR: |
2055d27a | 5793 | return RECUR (STMT_EXPR_STMT (t), rval); |
da7981e0 | 5794 | |
09b42213 | 5795 | case LAMBDA_EXPR: |
27db1f50 | 5796 | if (cxx_dialect >= cxx17) |
5797 | /* In C++17 lambdas can be constexpr, don't give up yet. */ | |
5798 | return true; | |
5799 | else if (flags & tf_error) | |
5800 | error_at (loc, "lambda-expression is not a constant expression " | |
5801 | "before C++17"); | |
5802 | return false; | |
5803 | ||
09b42213 | 5804 | case DYNAMIC_CAST_EXPR: |
5805 | case PSEUDO_DTOR_EXPR: | |
09b42213 | 5806 | case NEW_EXPR: |
5807 | case VEC_NEW_EXPR: | |
5808 | case DELETE_EXPR: | |
5809 | case VEC_DELETE_EXPR: | |
5810 | case THROW_EXPR: | |
d6a08f5c | 5811 | case OMP_PARALLEL: |
5812 | case OMP_TASK: | |
5813 | case OMP_FOR: | |
83728168 | 5814 | case OMP_SIMD: |
d6a08f5c | 5815 | case OMP_DISTRIBUTE: |
5816 | case OMP_TASKLOOP: | |
5817 | case OMP_TEAMS: | |
5818 | case OMP_TARGET_DATA: | |
5819 | case OMP_TARGET: | |
5820 | case OMP_SECTIONS: | |
5821 | case OMP_ORDERED: | |
5822 | case OMP_CRITICAL: | |
5823 | case OMP_SINGLE: | |
5824 | case OMP_SECTION: | |
5825 | case OMP_MASTER: | |
5826 | case OMP_TASKGROUP: | |
5827 | case OMP_TARGET_UPDATE: | |
5828 | case OMP_TARGET_ENTER_DATA: | |
5829 | case OMP_TARGET_EXIT_DATA: | |
09b42213 | 5830 | case OMP_ATOMIC: |
5831 | case OMP_ATOMIC_READ: | |
5832 | case OMP_ATOMIC_CAPTURE_OLD: | |
5833 | case OMP_ATOMIC_CAPTURE_NEW: | |
d6a08f5c | 5834 | case OACC_PARALLEL: |
5835 | case OACC_KERNELS: | |
5836 | case OACC_DATA: | |
5837 | case OACC_HOST_DATA: | |
5838 | case OACC_LOOP: | |
5839 | case OACC_CACHE: | |
5840 | case OACC_DECLARE: | |
5841 | case OACC_ENTER_DATA: | |
5842 | case OACC_EXIT_DATA: | |
5843 | case OACC_UPDATE: | |
09b42213 | 5844 | /* GCC internal stuff. */ |
5845 | case VA_ARG_EXPR: | |
5846 | case OBJ_TYPE_REF: | |
09b42213 | 5847 | case TRANSACTION_EXPR: |
9c96033c | 5848 | case ASM_EXPR: |
9abecca2 | 5849 | case AT_ENCODE_EXPR: |
9c96033c | 5850 | fail: |
09b42213 | 5851 | if (flags & tf_error) |
d6a08f5c | 5852 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 5853 | return false; |
5854 | ||
5855 | case TYPEID_EXPR: | |
5856 | /* -- a typeid expression whose operand is of polymorphic | |
5857 | class type; */ | |
5858 | { | |
5859 | tree e = TREE_OPERAND (t, 0); | |
5860 | if (!TYPE_P (e) && !type_dependent_expression_p (e) | |
5861 | && TYPE_POLYMORPHIC_P (TREE_TYPE (e))) | |
5862 | { | |
5863 | if (flags & tf_error) | |
d6a08f5c | 5864 | error_at (loc, "typeid-expression is not a constant expression " |
5865 | "because %qE is of polymorphic type", e); | |
09b42213 | 5866 | return false; |
5867 | } | |
5868 | return true; | |
5869 | } | |
5870 | ||
57e83b58 | 5871 | case POINTER_DIFF_EXPR: |
09b42213 | 5872 | case MINUS_EXPR: |
09b42213 | 5873 | want_rval = true; |
5874 | goto binary; | |
5875 | ||
5876 | case LT_EXPR: | |
5877 | case LE_EXPR: | |
5878 | case GT_EXPR: | |
5879 | case GE_EXPR: | |
5880 | case EQ_EXPR: | |
5881 | case NE_EXPR: | |
09b42213 | 5882 | want_rval = true; |
5883 | goto binary; | |
5884 | ||
9c96033c | 5885 | case PREINCREMENT_EXPR: |
5886 | case POSTINCREMENT_EXPR: | |
5887 | case PREDECREMENT_EXPR: | |
5888 | case POSTDECREMENT_EXPR: | |
5889 | if (cxx_dialect < cxx14) | |
5890 | goto fail; | |
5891 | goto unary; | |
5892 | ||
09b42213 | 5893 | case BIT_NOT_EXPR: |
5894 | /* A destructor. */ | |
5895 | if (TYPE_P (TREE_OPERAND (t, 0))) | |
5896 | return true; | |
e3533433 | 5897 | /* fall through. */ |
09b42213 | 5898 | |
09b42213 | 5899 | case CONJ_EXPR: |
5900 | case SAVE_EXPR: | |
5901 | case FIX_TRUNC_EXPR: | |
5902 | case FLOAT_EXPR: | |
5903 | case NEGATE_EXPR: | |
5904 | case ABS_EXPR: | |
1c67942e | 5905 | case ABSU_EXPR: |
09b42213 | 5906 | case TRUTH_NOT_EXPR: |
5907 | case FIXED_CONVERT_EXPR: | |
5908 | case UNARY_PLUS_EXPR: | |
6fdf70f5 | 5909 | case UNARY_LEFT_FOLD_EXPR: |
5910 | case UNARY_RIGHT_FOLD_EXPR: | |
9c96033c | 5911 | unary: |
2055d27a | 5912 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 5913 | |
5914 | case CAST_EXPR: | |
5915 | case CONST_CAST_EXPR: | |
5916 | case STATIC_CAST_EXPR: | |
5917 | case REINTERPRET_CAST_EXPR: | |
5918 | case IMPLICIT_CONV_EXPR: | |
5919 | if (cxx_dialect < cxx11 | |
5920 | && !dependent_type_p (TREE_TYPE (t)) | |
5921 | && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t))) | |
5922 | /* In C++98, a conversion to non-integral type can't be part of a | |
5923 | constant expression. */ | |
5924 | { | |
5925 | if (flags & tf_error) | |
d6a08f5c | 5926 | error_at (loc, |
5927 | "cast to non-integral type %qT in a constant expression", | |
5928 | TREE_TYPE (t)); | |
09b42213 | 5929 | return false; |
5930 | } | |
e0ccd480 | 5931 | /* This might be a conversion from a class to a (potentially) literal |
5932 | type. Let's consider it potentially constant since the conversion | |
5933 | might be a constexpr user-defined conversion. */ | |
5934 | else if (cxx_dialect >= cxx11 | |
5935 | && (dependent_type_p (TREE_TYPE (t)) | |
5936 | || !COMPLETE_TYPE_P (TREE_TYPE (t)) | |
5937 | || literal_type_p (TREE_TYPE (t))) | |
5938 | && TREE_OPERAND (t, 0)) | |
5939 | { | |
5940 | tree type = TREE_TYPE (TREE_OPERAND (t, 0)); | |
5941 | /* If this is a dependent type, it could end up being a class | |
5942 | with conversions. */ | |
5943 | if (type == NULL_TREE || WILDCARD_TYPE_P (type)) | |
5944 | return true; | |
5945 | /* Or a non-dependent class which has conversions. */ | |
5946 | else if (CLASS_TYPE_P (type) | |
5947 | && (TYPE_HAS_CONVERSION (type) || dependent_scope_p (type))) | |
5948 | return true; | |
5949 | } | |
09b42213 | 5950 | |
2055d27a | 5951 | return (RECUR (TREE_OPERAND (t, 0), |
90ad495b | 5952 | !TYPE_REF_P (TREE_TYPE (t)))); |
09b42213 | 5953 | |
9c96033c | 5954 | case BIND_EXPR: |
2055d27a | 5955 | return RECUR (BIND_EXPR_BODY (t), want_rval); |
9c96033c | 5956 | |
9c96033c | 5957 | case CLEANUP_POINT_EXPR: |
5958 | case MUST_NOT_THROW_EXPR: | |
5959 | case TRY_CATCH_EXPR: | |
7f67d68c | 5960 | case TRY_BLOCK: |
9c96033c | 5961 | case EH_SPEC_BLOCK: |
5962 | case EXPR_STMT: | |
09b42213 | 5963 | case PAREN_EXPR: |
5964 | case NON_DEPENDENT_EXPR: | |
5965 | /* For convenience. */ | |
5966 | case RETURN_EXPR: | |
d1980671 | 5967 | case LOOP_EXPR: |
5968 | case EXIT_EXPR: | |
2055d27a | 5969 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5970 | |
33603066 | 5971 | case DECL_EXPR: |
5972 | tmp = DECL_EXPR_DECL (t); | |
5973 | if (VAR_P (tmp) && !DECL_ARTIFICIAL (tmp)) | |
5974 | { | |
5975 | if (TREE_STATIC (tmp)) | |
5976 | { | |
5977 | if (flags & tf_error) | |
5978 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 5979 | "%<static%> in %<constexpr%> context", tmp); |
33603066 | 5980 | return false; |
5981 | } | |
5982 | else if (CP_DECL_THREAD_LOCAL_P (tmp)) | |
5983 | { | |
5984 | if (flags & tf_error) | |
5985 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 5986 | "%<thread_local%> in %<constexpr%> context", tmp); |
33603066 | 5987 | return false; |
5988 | } | |
282ea908 | 5989 | else if (!check_for_uninitialized_const_var |
5990 | (tmp, /*constexpr_context_p=*/true, flags)) | |
5991 | return false; | |
33603066 | 5992 | } |
5993 | return RECUR (tmp, want_rval); | |
5994 | ||
7f67d68c | 5995 | case TRY_FINALLY_EXPR: |
5996 | return (RECUR (TREE_OPERAND (t, 0), want_rval) | |
5997 | && RECUR (TREE_OPERAND (t, 1), any)); | |
5998 | ||
09b42213 | 5999 | case SCOPE_REF: |
2055d27a | 6000 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 6001 | |
6002 | case TARGET_EXPR: | |
07d8961c | 6003 | if (!TARGET_EXPR_DIRECT_INIT_P (t) |
6004 | && !literal_type_p (TREE_TYPE (t))) | |
09b42213 | 6005 | { |
6006 | if (flags & tf_error) | |
6007 | { | |
bc35ef65 | 6008 | auto_diagnostic_group d; |
d6a08f5c | 6009 | error_at (loc, "temporary of non-literal type %qT in a " |
6010 | "constant expression", TREE_TYPE (t)); | |
09b42213 | 6011 | explain_non_literal_class (TREE_TYPE (t)); |
6012 | } | |
6013 | return false; | |
6014 | } | |
e3533433 | 6015 | /* FALLTHRU */ |
09b42213 | 6016 | case INIT_EXPR: |
2055d27a | 6017 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 6018 | |
6019 | case CONSTRUCTOR: | |
6020 | { | |
6021 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
6022 | constructor_elt *ce; | |
6023 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2055d27a | 6024 | if (!RECUR (ce->value, want_rval)) |
09b42213 | 6025 | return false; |
6026 | return true; | |
6027 | } | |
6028 | ||
6029 | case TREE_LIST: | |
6030 | { | |
6031 | gcc_assert (TREE_PURPOSE (t) == NULL_TREE | |
6032 | || DECL_P (TREE_PURPOSE (t))); | |
2055d27a | 6033 | if (!RECUR (TREE_VALUE (t), want_rval)) |
09b42213 | 6034 | return false; |
6035 | if (TREE_CHAIN (t) == NULL_TREE) | |
6036 | return true; | |
2055d27a | 6037 | return RECUR (TREE_CHAIN (t), want_rval); |
09b42213 | 6038 | } |
6039 | ||
6040 | case TRUNC_DIV_EXPR: | |
6041 | case CEIL_DIV_EXPR: | |
6042 | case FLOOR_DIV_EXPR: | |
6043 | case ROUND_DIV_EXPR: | |
6044 | case TRUNC_MOD_EXPR: | |
6045 | case CEIL_MOD_EXPR: | |
6046 | case ROUND_MOD_EXPR: | |
6047 | { | |
6048 | tree denom = TREE_OPERAND (t, 1); | |
2055d27a | 6049 | if (!RECUR (denom, rval)) |
09b42213 | 6050 | return false; |
6051 | /* We can't call cxx_eval_outermost_constant_expr on an expression | |
21131a05 | 6052 | that hasn't been through instantiate_non_dependent_expr yet. */ |
09b42213 | 6053 | if (!processing_template_decl) |
6054 | denom = cxx_eval_outermost_constant_expr (denom, true); | |
6055 | if (integer_zerop (denom)) | |
6056 | { | |
6057 | if (flags & tf_error) | |
ea034e2c | 6058 | error ("division by zero is not a constant expression"); |
09b42213 | 6059 | return false; |
6060 | } | |
6061 | else | |
6062 | { | |
6063 | want_rval = true; | |
2055d27a | 6064 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 6065 | } |
6066 | } | |
6067 | ||
6068 | case COMPOUND_EXPR: | |
6069 | { | |
6070 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
6071 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
6072 | introduced by build_call_a. */ | |
6073 | tree op0 = TREE_OPERAND (t, 0); | |
6074 | tree op1 = TREE_OPERAND (t, 1); | |
6075 | STRIP_NOPS (op1); | |
6076 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
6077 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
2055d27a | 6078 | return RECUR (op0, want_rval); |
09b42213 | 6079 | else |
6080 | goto binary; | |
6081 | } | |
6082 | ||
6083 | /* If the first operand is the non-short-circuit constant, look at | |
6084 | the second operand; otherwise we only care about the first one for | |
6085 | potentiality. */ | |
6086 | case TRUTH_AND_EXPR: | |
6087 | case TRUTH_ANDIF_EXPR: | |
6088 | tmp = boolean_true_node; | |
6089 | goto truth; | |
6090 | case TRUTH_OR_EXPR: | |
6091 | case TRUTH_ORIF_EXPR: | |
6092 | tmp = boolean_false_node; | |
6093 | truth: | |
6094 | { | |
6095 | tree op = TREE_OPERAND (t, 0); | |
2055d27a | 6096 | if (!RECUR (op, rval)) |
09b42213 | 6097 | return false; |
6098 | if (!processing_template_decl) | |
6099 | op = cxx_eval_outermost_constant_expr (op, true); | |
6100 | if (tree_int_cst_equal (op, tmp)) | |
2055d27a | 6101 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 6102 | else |
6103 | return true; | |
6104 | } | |
6105 | ||
6106 | case PLUS_EXPR: | |
6107 | case MULT_EXPR: | |
6108 | case POINTER_PLUS_EXPR: | |
6109 | case RDIV_EXPR: | |
6110 | case EXACT_DIV_EXPR: | |
6111 | case MIN_EXPR: | |
6112 | case MAX_EXPR: | |
6113 | case LSHIFT_EXPR: | |
6114 | case RSHIFT_EXPR: | |
6115 | case LROTATE_EXPR: | |
6116 | case RROTATE_EXPR: | |
6117 | case BIT_IOR_EXPR: | |
6118 | case BIT_XOR_EXPR: | |
6119 | case BIT_AND_EXPR: | |
6120 | case TRUTH_XOR_EXPR: | |
6121 | case UNORDERED_EXPR: | |
6122 | case ORDERED_EXPR: | |
6123 | case UNLT_EXPR: | |
6124 | case UNLE_EXPR: | |
6125 | case UNGT_EXPR: | |
6126 | case UNGE_EXPR: | |
6127 | case UNEQ_EXPR: | |
6128 | case LTGT_EXPR: | |
6129 | case RANGE_EXPR: | |
6130 | case COMPLEX_EXPR: | |
6131 | want_rval = true; | |
6132 | /* Fall through. */ | |
6133 | case ARRAY_REF: | |
6134 | case ARRAY_RANGE_REF: | |
6135 | case MEMBER_REF: | |
6136 | case DOTSTAR_EXPR: | |
f0abe78f | 6137 | case MEM_REF: |
6fdf70f5 | 6138 | case BINARY_LEFT_FOLD_EXPR: |
6139 | case BINARY_RIGHT_FOLD_EXPR: | |
09b42213 | 6140 | binary: |
6141 | for (i = 0; i < 2; ++i) | |
2055d27a | 6142 | if (!RECUR (TREE_OPERAND (t, i), want_rval)) |
09b42213 | 6143 | return false; |
6144 | return true; | |
6145 | ||
09b42213 | 6146 | case VEC_PERM_EXPR: |
6147 | for (i = 0; i < 3; ++i) | |
2055d27a | 6148 | if (!RECUR (TREE_OPERAND (t, i), true)) |
09b42213 | 6149 | return false; |
6150 | return true; | |
6151 | ||
6152 | case COND_EXPR: | |
b0fe8b95 | 6153 | if (COND_EXPR_IS_VEC_DELETE (t)) |
6154 | { | |
6155 | if (flags & tf_error) | |
d6a08f5c | 6156 | error_at (loc, "%<delete[]%> is not a constant expression"); |
b0fe8b95 | 6157 | return false; |
6158 | } | |
6159 | /* Fall through. */ | |
6160 | case IF_STMT: | |
09b42213 | 6161 | case VEC_COND_EXPR: |
6162 | /* If the condition is a known constant, we know which of the legs we | |
6163 | care about; otherwise we only require that the condition and | |
6164 | either of the legs be potentially constant. */ | |
6165 | tmp = TREE_OPERAND (t, 0); | |
2055d27a | 6166 | if (!RECUR (tmp, rval)) |
09b42213 | 6167 | return false; |
6168 | if (!processing_template_decl) | |
6169 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
6170 | if (integer_zerop (tmp)) | |
2055d27a | 6171 | return RECUR (TREE_OPERAND (t, 2), want_rval); |
09b42213 | 6172 | else if (TREE_CODE (tmp) == INTEGER_CST) |
2055d27a | 6173 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 6174 | for (i = 1; i < 3; ++i) |
6175 | if (potential_constant_expression_1 (TREE_OPERAND (t, i), | |
7e1f8be4 | 6176 | want_rval, strict, now, tf_none)) |
09b42213 | 6177 | return true; |
6178 | if (flags & tf_error) | |
d6a08f5c | 6179 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 6180 | return false; |
6181 | ||
6182 | case VEC_INIT_EXPR: | |
6183 | if (VEC_INIT_EXPR_IS_CONSTEXPR (t)) | |
6184 | return true; | |
6185 | if (flags & tf_error) | |
6186 | { | |
d6a08f5c | 6187 | error_at (loc, "non-constant array initialization"); |
09b42213 | 6188 | diagnose_non_constexpr_vec_init (t); |
6189 | } | |
6190 | return false; | |
6191 | ||
db1ae94f | 6192 | case TYPE_DECL: |
6193 | case TAG_DEFN: | |
6194 | /* We can see these in statement-expressions. */ | |
6195 | return true; | |
6196 | ||
fd130325 | 6197 | case CLEANUP_STMT: |
d2c63826 | 6198 | case EMPTY_CLASS_EXPR: |
38ef3642 | 6199 | case PREDICT_EXPR: |
d2c63826 | 6200 | return false; |
6201 | ||
d1980671 | 6202 | case GOTO_EXPR: |
6203 | { | |
6204 | tree *target = &TREE_OPERAND (t, 0); | |
d40a1eac | 6205 | /* Gotos representing break and continue are OK. */ |
6206 | if (breaks (target) || continues (target)) | |
6207 | return true; | |
6208 | if (flags & tf_error) | |
d6a08f5c | 6209 | error_at (loc, "%<goto%> is not a constant expression"); |
d40a1eac | 6210 | return false; |
d1980671 | 6211 | } |
6212 | ||
24c6ee98 | 6213 | case ANNOTATE_EXPR: |
24c6ee98 | 6214 | return RECUR (TREE_OPERAND (t, 0), rval); |
6215 | ||
09b42213 | 6216 | default: |
6217 | if (objc_is_property_ref (t)) | |
6218 | return false; | |
6219 | ||
6220 | sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t))); | |
d40a1eac | 6221 | gcc_unreachable (); |
09b42213 | 6222 | return false; |
6223 | } | |
2055d27a | 6224 | #undef RECUR |
09b42213 | 6225 | } |
6226 | ||
6227 | /* The main entry point to the above. */ | |
6228 | ||
6229 | bool | |
6230 | potential_constant_expression (tree t) | |
6231 | { | |
7e1f8be4 | 6232 | return potential_constant_expression_1 (t, false, true, false, tf_none); |
09b42213 | 6233 | } |
6234 | ||
6235 | /* As above, but require a constant rvalue. */ | |
6236 | ||
6237 | bool | |
6238 | potential_rvalue_constant_expression (tree t) | |
6239 | { | |
7e1f8be4 | 6240 | return potential_constant_expression_1 (t, true, true, false, tf_none); |
09b42213 | 6241 | } |
6242 | ||
6243 | /* Like above, but complain about non-constant expressions. */ | |
6244 | ||
6245 | bool | |
6246 | require_potential_constant_expression (tree t) | |
6247 | { | |
786721dc | 6248 | return potential_constant_expression_1 (t, false, true, false, |
6249 | tf_warning_or_error); | |
09b42213 | 6250 | } |
6251 | ||
6252 | /* Cross product of the above. */ | |
6253 | ||
6254 | bool | |
6255 | require_potential_rvalue_constant_expression (tree t) | |
6256 | { | |
786721dc | 6257 | return potential_constant_expression_1 (t, true, true, false, |
6258 | tf_warning_or_error); | |
6259 | } | |
6260 | ||
6261 | /* Like above, but don't consider PARM_DECL a potential_constant_expression. */ | |
6262 | ||
6263 | bool | |
6264 | require_rvalue_constant_expression (tree t) | |
6265 | { | |
6266 | return potential_constant_expression_1 (t, true, true, true, | |
6267 | tf_warning_or_error); | |
7e1f8be4 | 6268 | } |
6269 | ||
6270 | /* Like potential_constant_expression, but don't consider possible constexpr | |
6271 | substitution of the current function. That is, PARM_DECL qualifies under | |
6272 | potential_constant_expression, but not here. | |
6273 | ||
6274 | This is basically what you can check when any actual constant values might | |
6275 | be value-dependent. */ | |
6276 | ||
6277 | bool | |
6278 | is_constant_expression (tree t) | |
6279 | { | |
6280 | return potential_constant_expression_1 (t, false, true, true, tf_none); | |
6281 | } | |
6282 | ||
6283 | /* Like above, but complain about non-constant expressions. */ | |
6284 | ||
6285 | bool | |
6286 | require_constant_expression (tree t) | |
6287 | { | |
6288 | return potential_constant_expression_1 (t, false, true, true, | |
6289 | tf_warning_or_error); | |
6290 | } | |
6291 | ||
6292 | /* Like is_constant_expression, but allow const variables that are not allowed | |
6293 | under constexpr rules. */ | |
6294 | ||
6295 | bool | |
6296 | is_static_init_expression (tree t) | |
6297 | { | |
6298 | return potential_constant_expression_1 (t, false, false, true, tf_none); | |
09b42213 | 6299 | } |
6300 | ||
29cf24ec | 6301 | /* Returns true if T is a potential constant expression that is not |
6302 | instantiation-dependent, and therefore a candidate for constant folding even | |
6303 | in a template. */ | |
6304 | ||
6305 | bool | |
7e1f8be4 | 6306 | is_nondependent_constant_expression (tree t) |
29cf24ec | 6307 | { |
6308 | return (!type_unknown_p (t) | |
6309 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6310 | && is_constant_expression (t) |
29cf24ec | 6311 | && !instantiation_dependent_expression_p (t)); |
6312 | } | |
6313 | ||
6314 | /* Returns true if T is a potential static initializer expression that is not | |
6315 | instantiation-dependent. */ | |
6316 | ||
6317 | bool | |
7e1f8be4 | 6318 | is_nondependent_static_init_expression (tree t) |
29cf24ec | 6319 | { |
6320 | return (!type_unknown_p (t) | |
6321 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6322 | && is_static_init_expression (t) |
29cf24ec | 6323 | && !instantiation_dependent_expression_p (t)); |
6324 | } | |
6325 | ||
a050099a | 6326 | /* Finalize constexpr processing after parsing. */ |
6327 | ||
6328 | void | |
6329 | fini_constexpr (void) | |
6330 | { | |
6331 | /* The contexpr call and fundef copies tables are no longer needed. */ | |
6332 | constexpr_call_table = NULL; | |
6333 | fundef_copies_table = NULL; | |
6334 | } | |
6335 | ||
09b42213 | 6336 | #include "gt-cp-constexpr.h" |