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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 | |
a0e9bfbb | 724 | && fndecl_built_in_p (fun, BUILT_IN_UNREACHABLE)) |
2fb20ba2 | 725 | return NULL_TREE; |
726 | } | |
727 | /* Fallthru. */ | |
728 | ||
09b42213 | 729 | default: |
730 | return error_mark_node; | |
731 | } | |
732 | } | |
733 | ||
734 | /* Subroutine of register_constexpr_fundef. BODY is the DECL_SAVED_TREE of | |
735 | FUN; do the necessary transformations to turn it into a single expression | |
736 | that we can store in the hash table. */ | |
737 | ||
738 | static tree | |
739 | massage_constexpr_body (tree fun, tree body) | |
740 | { | |
741 | if (DECL_CONSTRUCTOR_P (fun)) | |
742 | body = build_constexpr_constructor_member_initializers | |
743 | (DECL_CONTEXT (fun), body); | |
9c96033c | 744 | else if (cxx_dialect < cxx14) |
09b42213 | 745 | { |
746 | if (TREE_CODE (body) == EH_SPEC_BLOCK) | |
747 | body = EH_SPEC_STMTS (body); | |
748 | if (TREE_CODE (body) == MUST_NOT_THROW_EXPR) | |
749 | body = TREE_OPERAND (body, 0); | |
750 | body = constexpr_fn_retval (body); | |
751 | } | |
752 | return body; | |
753 | } | |
754 | ||
2f4cab3c | 755 | /* CTYPE is a type constructed from BODY. Return true if some |
756 | bases/fields are uninitialized, and complain if COMPLAIN. */ | |
09b42213 | 757 | |
758 | static bool | |
2f4cab3c | 759 | cx_check_missing_mem_inits (tree ctype, tree body, bool complain) |
09b42213 | 760 | { |
2f4cab3c | 761 | unsigned nelts = 0; |
762 | ||
763 | if (body) | |
764 | { | |
765 | if (TREE_CODE (body) != CONSTRUCTOR) | |
766 | return false; | |
767 | nelts = CONSTRUCTOR_NELTS (body); | |
768 | } | |
769 | tree field = TYPE_FIELDS (ctype); | |
09b42213 | 770 | |
771 | if (TREE_CODE (ctype) == UNION_TYPE) | |
772 | { | |
773 | if (nelts == 0 && next_initializable_field (field)) | |
774 | { | |
775 | if (complain) | |
776 | error ("%<constexpr%> constructor for union %qT must " | |
777 | "initialize exactly one non-static data member", ctype); | |
778 | return true; | |
779 | } | |
780 | return false; | |
781 | } | |
782 | ||
2f4cab3c | 783 | /* Iterate over the CONSTRUCTOR, checking any missing fields don't |
784 | need an explicit initialization. */ | |
785 | bool bad = false; | |
786 | for (unsigned i = 0; i <= nelts; ++i) | |
09b42213 | 787 | { |
2f4cab3c | 788 | tree index = NULL_TREE; |
789 | if (i < nelts) | |
09b42213 | 790 | { |
791 | index = CONSTRUCTOR_ELT (body, i)->index; | |
792 | /* Skip base and vtable inits. */ | |
793 | if (TREE_CODE (index) != FIELD_DECL | |
794 | || DECL_ARTIFICIAL (index)) | |
795 | continue; | |
796 | } | |
2f4cab3c | 797 | |
09b42213 | 798 | for (; field != index; field = DECL_CHAIN (field)) |
799 | { | |
800 | tree ftype; | |
2f4cab3c | 801 | if (TREE_CODE (field) != FIELD_DECL) |
802 | continue; | |
3cde3c29 | 803 | if (DECL_UNNAMED_BIT_FIELD (field)) |
09b42213 | 804 | continue; |
2f4cab3c | 805 | if (DECL_ARTIFICIAL (field)) |
806 | continue; | |
807 | if (ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
808 | { | |
809 | /* Recurse to check the anonummous aggregate member. */ | |
810 | bad |= cx_check_missing_mem_inits | |
811 | (TREE_TYPE (field), NULL_TREE, complain); | |
812 | if (bad && !complain) | |
813 | return true; | |
814 | continue; | |
815 | } | |
09b42213 | 816 | ftype = strip_array_types (TREE_TYPE (field)); |
817 | if (type_has_constexpr_default_constructor (ftype)) | |
818 | { | |
819 | /* It's OK to skip a member with a trivial constexpr ctor. | |
820 | A constexpr ctor that isn't trivial should have been | |
821 | added in by now. */ | |
822 | gcc_checking_assert (!TYPE_HAS_COMPLEX_DFLT (ftype) | |
823 | || errorcount != 0); | |
824 | continue; | |
825 | } | |
826 | if (!complain) | |
827 | return true; | |
bc35ef65 | 828 | auto_diagnostic_group d; |
859e2c29 | 829 | error ("member %qD must be initialized by mem-initializer " |
830 | "in %<constexpr%> constructor", field); | |
831 | inform (DECL_SOURCE_LOCATION (field), "declared here"); | |
09b42213 | 832 | bad = true; |
833 | } | |
834 | if (field == NULL_TREE) | |
835 | break; | |
2f4cab3c | 836 | |
837 | if (ANON_AGGR_TYPE_P (TREE_TYPE (index))) | |
838 | { | |
839 | /* Check the anonymous aggregate initializer is valid. */ | |
840 | bad |= cx_check_missing_mem_inits | |
841 | (TREE_TYPE (index), CONSTRUCTOR_ELT (body, i)->value, complain); | |
842 | if (bad && !complain) | |
843 | return true; | |
844 | } | |
09b42213 | 845 | field = DECL_CHAIN (field); |
846 | } | |
847 | ||
848 | return bad; | |
849 | } | |
850 | ||
851 | /* We are processing the definition of the constexpr function FUN. | |
852 | Check that its BODY fulfills the propriate requirements and | |
853 | enter it in the constexpr function definition table. | |
854 | For constructor BODY is actually the TREE_LIST of the | |
855 | member-initializer list. */ | |
856 | ||
857 | tree | |
858 | register_constexpr_fundef (tree fun, tree body) | |
859 | { | |
860 | constexpr_fundef entry; | |
861 | constexpr_fundef **slot; | |
862 | ||
863 | if (!is_valid_constexpr_fn (fun, !DECL_GENERATED_P (fun))) | |
864 | return NULL; | |
865 | ||
6a385150 | 866 | tree massaged = massage_constexpr_body (fun, body); |
867 | if (massaged == NULL_TREE || massaged == error_mark_node) | |
09b42213 | 868 | { |
869 | if (!DECL_CONSTRUCTOR_P (fun)) | |
5967b28b | 870 | error ("body of %<constexpr%> function %qD not a return-statement", |
871 | fun); | |
09b42213 | 872 | return NULL; |
873 | } | |
874 | ||
6a385150 | 875 | if (!potential_rvalue_constant_expression (massaged)) |
09b42213 | 876 | { |
877 | if (!DECL_GENERATED_P (fun)) | |
6a385150 | 878 | require_potential_rvalue_constant_expression (massaged); |
09b42213 | 879 | return NULL; |
880 | } | |
881 | ||
882 | if (DECL_CONSTRUCTOR_P (fun) | |
2f4cab3c | 883 | && cx_check_missing_mem_inits (DECL_CONTEXT (fun), |
884 | massaged, !DECL_GENERATED_P (fun))) | |
09b42213 | 885 | return NULL; |
886 | ||
887 | /* Create the constexpr function table if necessary. */ | |
888 | if (constexpr_fundef_table == NULL) | |
889 | constexpr_fundef_table | |
890 | = hash_table<constexpr_fundef_hasher>::create_ggc (101); | |
891 | ||
892 | entry.decl = fun; | |
893 | entry.body = body; | |
894 | slot = constexpr_fundef_table->find_slot (&entry, INSERT); | |
895 | ||
896 | gcc_assert (*slot == NULL); | |
897 | *slot = ggc_alloc<constexpr_fundef> (); | |
898 | **slot = entry; | |
899 | ||
900 | return fun; | |
901 | } | |
902 | ||
903 | /* FUN is a non-constexpr function called in a context that requires a | |
904 | constant expression. If it comes from a constexpr template, explain why | |
905 | the instantiation isn't constexpr. */ | |
906 | ||
907 | void | |
908 | explain_invalid_constexpr_fn (tree fun) | |
909 | { | |
910 | static hash_set<tree> *diagnosed; | |
911 | tree body; | |
912 | location_t save_loc; | |
33603066 | 913 | /* Only diagnose defaulted functions, lambdas, or instantiations. */ |
09b42213 | 914 | if (!DECL_DEFAULTED_FN (fun) |
33603066 | 915 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) |
09b42213 | 916 | && !is_instantiation_of_constexpr (fun)) |
917 | return; | |
918 | if (diagnosed == NULL) | |
919 | diagnosed = new hash_set<tree>; | |
920 | if (diagnosed->add (fun)) | |
921 | /* Already explained. */ | |
922 | return; | |
923 | ||
924 | save_loc = input_location; | |
33603066 | 925 | if (!lambda_static_thunk_p (fun)) |
926 | { | |
927 | /* Diagnostics should completely ignore the static thunk, so leave | |
928 | input_location set to our caller's location. */ | |
929 | input_location = DECL_SOURCE_LOCATION (fun); | |
930 | inform (input_location, | |
5967b28b | 931 | "%qD is not usable as a %<constexpr%> function because:", fun); |
33603066 | 932 | } |
09b42213 | 933 | /* First check the declaration. */ |
934 | if (is_valid_constexpr_fn (fun, true)) | |
935 | { | |
936 | /* Then if it's OK, the body. */ | |
33603066 | 937 | if (!DECL_DECLARED_CONSTEXPR_P (fun) |
938 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun))) | |
09b42213 | 939 | explain_implicit_non_constexpr (fun); |
940 | else | |
941 | { | |
942 | body = massage_constexpr_body (fun, DECL_SAVED_TREE (fun)); | |
943 | require_potential_rvalue_constant_expression (body); | |
944 | if (DECL_CONSTRUCTOR_P (fun)) | |
2f4cab3c | 945 | cx_check_missing_mem_inits (DECL_CONTEXT (fun), body, true); |
09b42213 | 946 | } |
947 | } | |
948 | input_location = save_loc; | |
949 | } | |
950 | ||
951 | /* Objects of this type represent calls to constexpr functions | |
952 | along with the bindings of parameters to their arguments, for | |
953 | the purpose of compile time evaluation. */ | |
954 | ||
955 | struct GTY((for_user)) constexpr_call { | |
956 | /* Description of the constexpr function definition. */ | |
957 | constexpr_fundef *fundef; | |
958 | /* Parameter bindings environment. A TREE_LIST where each TREE_PURPOSE | |
959 | is a parameter _DECL and the TREE_VALUE is the value of the parameter. | |
960 | Note: This arrangement is made to accommodate the use of | |
961 | iterative_hash_template_arg (see pt.c). If you change this | |
962 | representation, also change the hash calculation in | |
963 | cxx_eval_call_expression. */ | |
964 | tree bindings; | |
965 | /* Result of the call. | |
966 | NULL means the call is being evaluated. | |
967 | error_mark_node means that the evaluation was erroneous; | |
968 | otherwise, the actuall value of the call. */ | |
969 | tree result; | |
970 | /* The hash of this call; we remember it here to avoid having to | |
971 | recalculate it when expanding the hash table. */ | |
972 | hashval_t hash; | |
973 | }; | |
974 | ||
b594087e | 975 | struct constexpr_call_hasher : ggc_ptr_hash<constexpr_call> |
09b42213 | 976 | { |
977 | static hashval_t hash (constexpr_call *); | |
978 | static bool equal (constexpr_call *, constexpr_call *); | |
cf72f34d | 979 | }; |
980 | ||
2a2770c6 | 981 | enum constexpr_switch_state { |
982 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
983 | and default: label for that switch has not been seen yet. */ | |
984 | css_default_not_seen, | |
985 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
986 | and default: label for that switch has been seen already. */ | |
987 | css_default_seen, | |
988 | /* Used when processing a switch for the second time by | |
989 | cxx_eval_switch_expr, where default: label should match. */ | |
990 | css_default_processing | |
991 | }; | |
992 | ||
cf72f34d | 993 | /* The constexpr expansion context. CALL is the current function |
994 | expansion, CTOR is the current aggregate initializer, OBJECT is the | |
995 | object being initialized by CTOR, either a VAR_DECL or a _REF. VALUES | |
996 | is a map of values of variables initialized within the expression. */ | |
997 | ||
998 | struct constexpr_ctx { | |
f9885b8a | 999 | /* The innermost call we're evaluating. */ |
cf72f34d | 1000 | constexpr_call *call; |
f9885b8a | 1001 | /* Values for any temporaries or local variables within the |
1002 | constant-expression. */ | |
cf72f34d | 1003 | hash_map<tree,tree> *values; |
2631cb67 | 1004 | /* SAVE_EXPRs that we've seen within the current LOOP_EXPR. NULL if we |
1005 | aren't inside a loop. */ | |
1006 | hash_set<tree> *save_exprs; | |
f9885b8a | 1007 | /* The CONSTRUCTOR we're currently building up for an aggregate |
1008 | initializer. */ | |
cf72f34d | 1009 | tree ctor; |
f9885b8a | 1010 | /* The object we're building the CONSTRUCTOR for. */ |
cf72f34d | 1011 | tree object; |
2a2770c6 | 1012 | /* If inside SWITCH_EXPR. */ |
1013 | constexpr_switch_state *css_state; | |
f9885b8a | 1014 | /* Whether we should error on a non-constant expression or fail quietly. */ |
f83e6885 | 1015 | bool quiet; |
f9885b8a | 1016 | /* Whether we are strictly conforming to constant expression rules or |
1017 | trying harder to get a constant value. */ | |
2055d27a | 1018 | bool strict; |
18d371d3 | 1019 | /* Whether __builtin_is_constant_evaluated () should be true. */ |
1020 | bool pretend_const_required; | |
cf72f34d | 1021 | }; |
09b42213 | 1022 | |
1023 | /* A table of all constexpr calls that have been evaluated by the | |
1024 | compiler in this translation unit. */ | |
1025 | ||
a050099a | 1026 | static GTY (()) hash_table<constexpr_call_hasher> *constexpr_call_table; |
09b42213 | 1027 | |
cf72f34d | 1028 | static tree cxx_eval_constant_expression (const constexpr_ctx *, tree, |
b2a43197 | 1029 | bool, bool *, bool *, tree * = NULL); |
09b42213 | 1030 | |
1031 | /* Compute a hash value for a constexpr call representation. */ | |
1032 | ||
1033 | inline hashval_t | |
1034 | constexpr_call_hasher::hash (constexpr_call *info) | |
1035 | { | |
1036 | return info->hash; | |
1037 | } | |
1038 | ||
1039 | /* Return true if the objects pointed to by P and Q represent calls | |
1040 | to the same constexpr function with the same arguments. | |
1041 | Otherwise, return false. */ | |
1042 | ||
1043 | bool | |
1044 | constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs) | |
1045 | { | |
1046 | tree lhs_bindings; | |
1047 | tree rhs_bindings; | |
1048 | if (lhs == rhs) | |
c751e2cd | 1049 | return true; |
1050 | if (lhs->hash != rhs->hash) | |
1051 | return false; | |
09b42213 | 1052 | if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef)) |
c751e2cd | 1053 | return false; |
09b42213 | 1054 | lhs_bindings = lhs->bindings; |
1055 | rhs_bindings = rhs->bindings; | |
1056 | while (lhs_bindings != NULL && rhs_bindings != NULL) | |
1057 | { | |
1058 | tree lhs_arg = TREE_VALUE (lhs_bindings); | |
1059 | tree rhs_arg = TREE_VALUE (rhs_bindings); | |
1060 | gcc_assert (TREE_TYPE (lhs_arg) == TREE_TYPE (rhs_arg)); | |
1061 | if (!cp_tree_equal (lhs_arg, rhs_arg)) | |
c751e2cd | 1062 | return false; |
09b42213 | 1063 | lhs_bindings = TREE_CHAIN (lhs_bindings); |
1064 | rhs_bindings = TREE_CHAIN (rhs_bindings); | |
1065 | } | |
1066 | return lhs_bindings == rhs_bindings; | |
1067 | } | |
1068 | ||
1069 | /* Initialize the constexpr call table, if needed. */ | |
1070 | ||
1071 | static void | |
1072 | maybe_initialize_constexpr_call_table (void) | |
1073 | { | |
1074 | if (constexpr_call_table == NULL) | |
1075 | constexpr_call_table = hash_table<constexpr_call_hasher>::create_ggc (101); | |
1076 | } | |
1077 | ||
4f7ebe46 | 1078 | /* During constexpr CALL_EXPR evaluation, to avoid issues with sharing when |
1079 | a function happens to get called recursively, we unshare the callee | |
1080 | function's body and evaluate this unshared copy instead of evaluating the | |
1081 | original body. | |
1082 | ||
1083 | FUNDEF_COPIES_TABLE is a per-function freelist of these unshared function | |
1084 | copies. The underlying data structure of FUNDEF_COPIES_TABLE is a hash_map | |
a050099a | 1085 | that's keyed off of the original FUNCTION_DECL and whose value is a |
1086 | TREE_LIST of this function's unused copies awaiting reuse. | |
4f7ebe46 | 1087 | |
a050099a | 1088 | This is not GC-deletable to avoid GC affecting UID generation. */ |
4f7ebe46 | 1089 | |
a050099a | 1090 | static GTY(()) hash_map<tree, tree> *fundef_copies_table; |
4f7ebe46 | 1091 | |
1092 | /* Initialize FUNDEF_COPIES_TABLE if it's not initialized. */ | |
1093 | ||
1094 | static void | |
1095 | maybe_initialize_fundef_copies_table () | |
1096 | { | |
a050099a | 1097 | if (fundef_copies_table == NULL) |
1098 | fundef_copies_table = hash_map<tree,tree>::create_ggc (101); | |
4f7ebe46 | 1099 | } |
1100 | ||
1101 | /* Reuse a copy or create a new unshared copy of the function FUN. | |
886d5463 | 1102 | Return this copy. We use a TREE_LIST whose PURPOSE is body, VALUE |
1103 | is parms, TYPE is result. */ | |
4f7ebe46 | 1104 | |
a050099a | 1105 | static tree |
4f7ebe46 | 1106 | get_fundef_copy (tree fun) |
1107 | { | |
1108 | maybe_initialize_fundef_copies_table (); | |
1109 | ||
a050099a | 1110 | tree copy; |
886d5463 | 1111 | bool existed; |
1112 | tree *slot = &fundef_copies_table->get_or_insert (fun, &existed); | |
1113 | ||
1114 | if (!existed) | |
4f7ebe46 | 1115 | { |
886d5463 | 1116 | /* There is no cached function available, or in use. We can use |
1117 | the function directly. That the slot is now created records | |
1118 | that this function is now in use. */ | |
1119 | copy = build_tree_list (DECL_SAVED_TREE (fun), DECL_ARGUMENTS (fun)); | |
1120 | TREE_TYPE (copy) = DECL_RESULT (fun); | |
1121 | } | |
1122 | else if (*slot == NULL_TREE) | |
1123 | { | |
1124 | /* We've already used the function itself, so make a copy. */ | |
a050099a | 1125 | copy = build_tree_list (NULL, NULL); |
a050099a | 1126 | TREE_PURPOSE (copy) = copy_fn (fun, TREE_VALUE (copy), TREE_TYPE (copy)); |
4f7ebe46 | 1127 | } |
1128 | else | |
1129 | { | |
886d5463 | 1130 | /* We have a cached function available. */ |
4f7ebe46 | 1131 | copy = *slot; |
a050099a | 1132 | *slot = TREE_CHAIN (copy); |
4f7ebe46 | 1133 | } |
1134 | ||
1135 | return copy; | |
1136 | } | |
1137 | ||
886d5463 | 1138 | /* Save the copy COPY of function FUN for later reuse by |
1139 | get_fundef_copy(). By construction, there will always be an entry | |
1140 | to find. */ | |
4f7ebe46 | 1141 | |
1142 | static void | |
a050099a | 1143 | save_fundef_copy (tree fun, tree copy) |
4f7ebe46 | 1144 | { |
886d5463 | 1145 | tree *slot = fundef_copies_table->get (fun); |
a050099a | 1146 | TREE_CHAIN (copy) = *slot; |
4f7ebe46 | 1147 | *slot = copy; |
1148 | } | |
1149 | ||
09b42213 | 1150 | /* We have an expression tree T that represents a call, either CALL_EXPR |
1151 | or AGGR_INIT_EXPR. Return the Nth argument. */ | |
1152 | ||
1153 | static inline tree | |
1154 | get_nth_callarg (tree t, int n) | |
1155 | { | |
1156 | switch (TREE_CODE (t)) | |
1157 | { | |
1158 | case CALL_EXPR: | |
1159 | return CALL_EXPR_ARG (t, n); | |
1160 | ||
1161 | case AGGR_INIT_EXPR: | |
1162 | return AGGR_INIT_EXPR_ARG (t, n); | |
1163 | ||
1164 | default: | |
1165 | gcc_unreachable (); | |
1166 | return NULL; | |
1167 | } | |
1168 | } | |
1169 | ||
09b42213 | 1170 | /* Attempt to evaluate T which represents a call to a builtin function. |
1171 | We assume here that all builtin functions evaluate to scalar types | |
1172 | represented by _CST nodes. */ | |
1173 | ||
1174 | static tree | |
f1c6af10 | 1175 | cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, |
1227ba74 | 1176 | bool lval, |
09b42213 | 1177 | bool *non_constant_p, bool *overflow_p) |
1178 | { | |
1179 | const int nargs = call_expr_nargs (t); | |
1180 | tree *args = (tree *) alloca (nargs * sizeof (tree)); | |
1181 | tree new_call; | |
1182 | int i; | |
f1c6af10 | 1183 | |
1184 | /* Don't fold __builtin_constant_p within a constexpr function. */ | |
18d371d3 | 1185 | bool bi_const_p = DECL_IS_BUILTIN_CONSTANT_P (fun); |
efe6a40a | 1186 | |
0f5cec54 | 1187 | /* If we aren't requiring a constant expression, defer __builtin_constant_p |
1188 | in a constexpr function until we have values for the parameters. */ | |
efe6a40a | 1189 | if (bi_const_p |
0f5cec54 | 1190 | && ctx->quiet |
f1c6af10 | 1191 | && current_function_decl |
1192 | && DECL_DECLARED_CONSTEXPR_P (current_function_decl)) | |
09b42213 | 1193 | { |
f1c6af10 | 1194 | *non_constant_p = true; |
1195 | return t; | |
09b42213 | 1196 | } |
f1c6af10 | 1197 | |
18d371d3 | 1198 | /* For __builtin_is_constant_evaluated, defer it if not |
1199 | ctx->pretend_const_required, otherwise fold it to true. */ | |
a0e9bfbb | 1200 | if (fndecl_built_in_p (fun, CP_BUILT_IN_IS_CONSTANT_EVALUATED, |
1201 | BUILT_IN_FRONTEND)) | |
18d371d3 | 1202 | { |
1203 | if (!ctx->pretend_const_required) | |
1204 | { | |
1205 | *non_constant_p = true; | |
1206 | return t; | |
1207 | } | |
1208 | return boolean_true_node; | |
1209 | } | |
1210 | ||
f1c6af10 | 1211 | /* Be permissive for arguments to built-ins; __builtin_constant_p should |
1212 | return constant false for a non-constant argument. */ | |
1213 | constexpr_ctx new_ctx = *ctx; | |
1214 | new_ctx.quiet = true; | |
1215 | bool dummy1 = false, dummy2 = false; | |
1216 | for (i = 0; i < nargs; ++i) | |
efe6a40a | 1217 | { |
91b66c3c | 1218 | args[i] = CALL_EXPR_ARG (t, i); |
1219 | /* If builtin_valid_in_constant_expr_p is true, | |
1220 | potential_constant_expression_1 has not recursed into the arguments | |
1221 | of the builtin, verify it here. */ | |
1222 | if (!builtin_valid_in_constant_expr_p (fun) | |
1223 | || potential_constant_expression (args[i])) | |
1224 | args[i] = cxx_eval_constant_expression (&new_ctx, args[i], false, | |
1225 | &dummy1, &dummy2); | |
efe6a40a | 1226 | if (bi_const_p) |
1227 | /* For __built_in_constant_p, fold all expressions with constant values | |
1228 | even if they aren't C++ constant-expressions. */ | |
1229 | args[i] = cp_fully_fold (args[i]); | |
1230 | } | |
f1c6af10 | 1231 | |
1232 | bool save_ffbcp = force_folding_builtin_constant_p; | |
1233 | force_folding_builtin_constant_p = true; | |
051eb924 | 1234 | new_call = fold_builtin_call_array (EXPR_LOCATION (t), TREE_TYPE (t), |
1235 | CALL_EXPR_FN (t), nargs, args); | |
f1c6af10 | 1236 | force_folding_builtin_constant_p = save_ffbcp; |
051eb924 | 1237 | if (new_call == NULL) |
1238 | { | |
1239 | if (!*non_constant_p && !ctx->quiet) | |
1240 | { | |
2fb20ba2 | 1241 | /* Do not allow__builtin_unreachable in constexpr function. |
1242 | The __builtin_unreachable call with BUILTINS_LOCATION | |
1243 | comes from cp_maybe_instrument_return. */ | |
a0e9bfbb | 1244 | if (fndecl_built_in_p (fun, BUILT_IN_UNREACHABLE) |
2fb20ba2 | 1245 | && EXPR_LOCATION (t) == BUILTINS_LOCATION) |
5967b28b | 1246 | error ("%<constexpr%> call flows off the end of the function"); |
2fb20ba2 | 1247 | else |
1248 | { | |
1249 | new_call = build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t), | |
1250 | CALL_EXPR_FN (t), nargs, args); | |
1251 | error ("%q+E is not a constant expression", new_call); | |
1252 | } | |
051eb924 | 1253 | } |
1254 | *non_constant_p = true; | |
1255 | return t; | |
1256 | } | |
1257 | ||
7e1f8be4 | 1258 | if (!is_constant_expression (new_call)) |
051eb924 | 1259 | { |
1260 | if (!*non_constant_p && !ctx->quiet) | |
1261 | error ("%q+E is not a constant expression", new_call); | |
1262 | *non_constant_p = true; | |
1263 | return t; | |
1264 | } | |
1265 | ||
1266 | return cxx_eval_constant_expression (&new_ctx, new_call, lval, | |
1267 | non_constant_p, overflow_p); | |
09b42213 | 1268 | } |
1269 | ||
1270 | /* TEMP is the constant value of a temporary object of type TYPE. Adjust | |
1271 | the type of the value to match. */ | |
1272 | ||
1273 | static tree | |
1274 | adjust_temp_type (tree type, tree temp) | |
1275 | { | |
1276 | if (TREE_TYPE (temp) == type) | |
1277 | return temp; | |
1278 | /* Avoid wrapping an aggregate value in a NOP_EXPR. */ | |
1279 | if (TREE_CODE (temp) == CONSTRUCTOR) | |
1280 | return build_constructor (type, CONSTRUCTOR_ELTS (temp)); | |
1281 | gcc_assert (scalarish_type_p (type)); | |
1282 | return cp_fold_convert (type, temp); | |
1283 | } | |
1284 | ||
e283bb4f | 1285 | /* Callback for walk_tree used by unshare_constructor. */ |
1286 | ||
1287 | static tree | |
1288 | find_constructor (tree *tp, int *walk_subtrees, void *) | |
1289 | { | |
1290 | if (TYPE_P (*tp)) | |
1291 | *walk_subtrees = 0; | |
1292 | if (TREE_CODE (*tp) == CONSTRUCTOR) | |
1293 | return *tp; | |
1294 | return NULL_TREE; | |
1295 | } | |
1296 | ||
1297 | /* If T is a CONSTRUCTOR or an expression that has a CONSTRUCTOR node as a | |
1298 | subexpression, return an unshared copy of T. Otherwise return T. */ | |
1299 | ||
1300 | static tree | |
1301 | unshare_constructor (tree t) | |
1302 | { | |
1303 | tree ctor = walk_tree (&t, find_constructor, NULL, NULL); | |
1304 | if (ctor != NULL_TREE) | |
1305 | return unshare_expr (t); | |
1306 | return t; | |
1307 | } | |
1308 | ||
09b42213 | 1309 | /* Subroutine of cxx_eval_call_expression. |
1310 | We are processing a call expression (either CALL_EXPR or | |
cf72f34d | 1311 | AGGR_INIT_EXPR) in the context of CTX. Evaluate |
09b42213 | 1312 | all arguments and bind their values to correspondings |
1313 | parameters, making up the NEW_CALL context. */ | |
1314 | ||
1315 | static void | |
cf72f34d | 1316 | cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, |
09b42213 | 1317 | constexpr_call *new_call, |
c8f6aeb1 | 1318 | bool *non_constant_p, bool *overflow_p, |
1319 | bool *non_constant_args) | |
09b42213 | 1320 | { |
1321 | const int nargs = call_expr_nargs (t); | |
1322 | tree fun = new_call->fundef->decl; | |
1323 | tree parms = DECL_ARGUMENTS (fun); | |
1324 | int i; | |
9c96033c | 1325 | tree *p = &new_call->bindings; |
09b42213 | 1326 | for (i = 0; i < nargs; ++i) |
1327 | { | |
1328 | tree x, arg; | |
1329 | tree type = parms ? TREE_TYPE (parms) : void_type_node; | |
09b42213 | 1330 | x = get_nth_callarg (t, i); |
cf72f34d | 1331 | /* For member function, the first argument is a pointer to the implied |
1332 | object. For a constructor, it might still be a dummy object, in | |
9c96033c | 1333 | which case we get the real argument from ctx. */ |
cf72f34d | 1334 | if (i == 0 && DECL_CONSTRUCTOR_P (fun) |
1335 | && is_dummy_object (x)) | |
1336 | { | |
1337 | x = ctx->object; | |
c017458d | 1338 | x = build_address (x); |
cf72f34d | 1339 | } |
2e1c71c2 | 1340 | arg = cxx_eval_constant_expression (ctx, x, /*lval=*/false, |
b2a43197 | 1341 | non_constant_p, overflow_p); |
09b42213 | 1342 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 1343 | if (*non_constant_p && ctx->quiet) |
09b42213 | 1344 | return; |
1345 | /* Just discard ellipsis args after checking their constantitude. */ | |
1346 | if (!parms) | |
1347 | continue; | |
2ba934c7 | 1348 | |
1349 | if (!*non_constant_p) | |
1350 | { | |
24d5b4f0 | 1351 | /* Don't share a CONSTRUCTOR that might be changed. */ |
1352 | arg = unshare_constructor (arg); | |
2ba934c7 | 1353 | /* Make sure the binding has the same type as the parm. But |
1354 | only for constant args. */ | |
90ad495b | 1355 | if (!TYPE_REF_P (type)) |
2ba934c7 | 1356 | arg = adjust_temp_type (type, arg); |
1357 | if (!TREE_CONSTANT (arg)) | |
1358 | *non_constant_args = true; | |
1359 | *p = build_tree_list (parms, arg); | |
1360 | p = &TREE_CHAIN (*p); | |
1361 | } | |
09b42213 | 1362 | parms = TREE_CHAIN (parms); |
1363 | } | |
1364 | } | |
1365 | ||
1366 | /* Variables and functions to manage constexpr call expansion context. | |
1367 | These do not need to be marked for PCH or GC. */ | |
1368 | ||
1369 | /* FIXME remember and print actual constant arguments. */ | |
16fb756f | 1370 | static vec<tree> call_stack; |
09b42213 | 1371 | static int call_stack_tick; |
1372 | static int last_cx_error_tick; | |
1373 | ||
1374 | static bool | |
1375 | push_cx_call_context (tree call) | |
1376 | { | |
1377 | ++call_stack_tick; | |
1378 | if (!EXPR_HAS_LOCATION (call)) | |
1379 | SET_EXPR_LOCATION (call, input_location); | |
1380 | call_stack.safe_push (call); | |
1381 | if (call_stack.length () > (unsigned) max_constexpr_depth) | |
1382 | return false; | |
1383 | return true; | |
1384 | } | |
1385 | ||
1386 | static void | |
1387 | pop_cx_call_context (void) | |
1388 | { | |
1389 | ++call_stack_tick; | |
1390 | call_stack.pop (); | |
1391 | } | |
1392 | ||
1393 | vec<tree> | |
1394 | cx_error_context (void) | |
1395 | { | |
1396 | vec<tree> r = vNULL; | |
1397 | if (call_stack_tick != last_cx_error_tick | |
1398 | && !call_stack.is_empty ()) | |
1399 | r = call_stack; | |
1400 | last_cx_error_tick = call_stack_tick; | |
1401 | return r; | |
1402 | } | |
1403 | ||
732905bb | 1404 | /* Evaluate a call T to a GCC internal function when possible and return |
1405 | the evaluated result or, under the control of CTX, give an error, set | |
1406 | NON_CONSTANT_P, and return the unevaluated call T otherwise. */ | |
1407 | ||
1408 | static tree | |
1409 | cxx_eval_internal_function (const constexpr_ctx *ctx, tree t, | |
1410 | bool lval, | |
1411 | bool *non_constant_p, bool *overflow_p) | |
1412 | { | |
1413 | enum tree_code opcode = ERROR_MARK; | |
1414 | ||
1415 | switch (CALL_EXPR_IFN (t)) | |
1416 | { | |
1417 | case IFN_UBSAN_NULL: | |
1418 | case IFN_UBSAN_BOUNDS: | |
1419 | case IFN_UBSAN_VPTR: | |
3c77f69c | 1420 | case IFN_FALLTHROUGH: |
732905bb | 1421 | return void_node; |
1422 | ||
1423 | case IFN_ADD_OVERFLOW: | |
1424 | opcode = PLUS_EXPR; | |
1425 | break; | |
1426 | case IFN_SUB_OVERFLOW: | |
1427 | opcode = MINUS_EXPR; | |
1428 | break; | |
1429 | case IFN_MUL_OVERFLOW: | |
1430 | opcode = MULT_EXPR; | |
1431 | break; | |
1432 | ||
6e1b2ffb | 1433 | case IFN_LAUNDER: |
1434 | return cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), | |
1435 | false, non_constant_p, overflow_p); | |
1436 | ||
732905bb | 1437 | default: |
1438 | if (!ctx->quiet) | |
d3a3cfb8 | 1439 | error_at (cp_expr_loc_or_loc (t, input_location), |
732905bb | 1440 | "call to internal function %qE", t); |
1441 | *non_constant_p = true; | |
1442 | return t; | |
1443 | } | |
1444 | ||
1445 | /* Evaluate constant arguments using OPCODE and return a complex | |
1446 | number containing the result and the overflow bit. */ | |
1447 | tree arg0 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), lval, | |
1448 | non_constant_p, overflow_p); | |
1449 | tree arg1 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 1), lval, | |
1450 | non_constant_p, overflow_p); | |
1451 | ||
1452 | if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) | |
1453 | { | |
d3a3cfb8 | 1454 | location_t loc = cp_expr_loc_or_loc (t, input_location); |
732905bb | 1455 | tree type = TREE_TYPE (TREE_TYPE (t)); |
1456 | tree result = fold_binary_loc (loc, opcode, type, | |
1457 | fold_convert_loc (loc, type, arg0), | |
1458 | fold_convert_loc (loc, type, arg1)); | |
1459 | tree ovf | |
1460 | = build_int_cst (type, arith_overflowed_p (opcode, type, arg0, arg1)); | |
1461 | /* Reset TREE_OVERFLOW to avoid warnings for the overflow. */ | |
1462 | if (TREE_OVERFLOW (result)) | |
1463 | TREE_OVERFLOW (result) = 0; | |
1464 | ||
1465 | return build_complex (TREE_TYPE (t), result, ovf); | |
1466 | } | |
1467 | ||
1468 | *non_constant_p = true; | |
1469 | return t; | |
1470 | } | |
1471 | ||
165d0d5b | 1472 | /* Clean CONSTRUCTOR_NO_CLEARING from CTOR and its sub-aggregates. */ |
79cdb4f5 | 1473 | |
1474 | static void | |
1475 | clear_no_implicit_zero (tree ctor) | |
1476 | { | |
165d0d5b | 1477 | if (CONSTRUCTOR_NO_CLEARING (ctor)) |
79cdb4f5 | 1478 | { |
165d0d5b | 1479 | CONSTRUCTOR_NO_CLEARING (ctor) = false; |
79cdb4f5 | 1480 | tree elt; unsigned HOST_WIDE_INT idx; |
1481 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (ctor), idx, elt) | |
1482 | if (TREE_CODE (elt) == CONSTRUCTOR) | |
1483 | clear_no_implicit_zero (elt); | |
1484 | } | |
1485 | } | |
1486 | ||
09b42213 | 1487 | /* Subroutine of cxx_eval_constant_expression. |
1488 | Evaluate the call expression tree T in the context of OLD_CALL expression | |
1489 | evaluation. */ | |
1490 | ||
1491 | static tree | |
cf72f34d | 1492 | cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1493 | bool lval, |
09b42213 | 1494 | bool *non_constant_p, bool *overflow_p) |
1495 | { | |
d3a3cfb8 | 1496 | location_t loc = cp_expr_loc_or_loc (t, input_location); |
09b42213 | 1497 | tree fun = get_function_named_in_call (t); |
09b42213 | 1498 | constexpr_call new_call = { NULL, NULL, NULL, 0 }; |
09b42213 | 1499 | bool depth_ok; |
1500 | ||
6b71bdb4 | 1501 | if (fun == NULL_TREE) |
732905bb | 1502 | return cxx_eval_internal_function (ctx, t, lval, |
1503 | non_constant_p, overflow_p); | |
6b71bdb4 | 1504 | |
09b42213 | 1505 | if (TREE_CODE (fun) != FUNCTION_DECL) |
1506 | { | |
1507 | /* Might be a constexpr function pointer. */ | |
f83e6885 | 1508 | fun = cxx_eval_constant_expression (ctx, fun, |
1227ba74 | 1509 | /*lval*/false, non_constant_p, |
b2a43197 | 1510 | overflow_p); |
09b42213 | 1511 | STRIP_NOPS (fun); |
1512 | if (TREE_CODE (fun) == ADDR_EXPR) | |
1513 | fun = TREE_OPERAND (fun, 0); | |
1514 | } | |
1515 | if (TREE_CODE (fun) != FUNCTION_DECL) | |
1516 | { | |
f83e6885 | 1517 | if (!ctx->quiet && !*non_constant_p) |
5967b28b | 1518 | error_at (loc, "expression %qE does not designate a %<constexpr%> " |
09b42213 | 1519 | "function", fun); |
1520 | *non_constant_p = true; | |
1521 | return t; | |
1522 | } | |
1523 | if (DECL_CLONED_FUNCTION_P (fun)) | |
1524 | fun = DECL_CLONED_FUNCTION (fun); | |
6b71bdb4 | 1525 | |
1526 | if (is_ubsan_builtin_p (fun)) | |
1527 | return void_node; | |
1528 | ||
a0e9bfbb | 1529 | if (fndecl_built_in_p (fun)) |
f1c6af10 | 1530 | return cxx_eval_builtin_function_call (ctx, t, fun, |
1227ba74 | 1531 | lval, non_constant_p, overflow_p); |
09b42213 | 1532 | if (!DECL_DECLARED_CONSTEXPR_P (fun)) |
1533 | { | |
f83e6885 | 1534 | if (!ctx->quiet) |
09b42213 | 1535 | { |
1dcd84cf | 1536 | if (!lambda_static_thunk_p (fun)) |
5967b28b | 1537 | error_at (loc, "call to non-%<constexpr%> function %qD", fun); |
09b42213 | 1538 | explain_invalid_constexpr_fn (fun); |
1539 | } | |
1540 | *non_constant_p = true; | |
1541 | return t; | |
1542 | } | |
1543 | ||
9ebe2ea3 | 1544 | constexpr_ctx new_ctx = *ctx; |
1545 | if (DECL_CONSTRUCTOR_P (fun) && !ctx->object | |
1546 | && TREE_CODE (t) == AGGR_INIT_EXPR) | |
1547 | { | |
1548 | /* We want to have an initialization target for an AGGR_INIT_EXPR. | |
1549 | If we don't already have one in CTX, use the AGGR_INIT_EXPR_SLOT. */ | |
1550 | new_ctx.object = AGGR_INIT_EXPR_SLOT (t); | |
1551 | tree ctor = new_ctx.ctor = build_constructor (DECL_CONTEXT (fun), NULL); | |
165d0d5b | 1552 | CONSTRUCTOR_NO_CLEARING (ctor) = true; |
9ebe2ea3 | 1553 | ctx->values->put (new_ctx.object, ctor); |
1554 | ctx = &new_ctx; | |
1555 | } | |
1556 | ||
09b42213 | 1557 | /* Shortcut trivial constructor/op=. */ |
1558 | if (trivial_fn_p (fun)) | |
1559 | { | |
9ebe2ea3 | 1560 | tree init = NULL_TREE; |
09b42213 | 1561 | if (call_expr_nargs (t) == 2) |
9ebe2ea3 | 1562 | init = convert_from_reference (get_nth_callarg (t, 1)); |
09b42213 | 1563 | else if (TREE_CODE (t) == AGGR_INIT_EXPR |
1564 | && AGGR_INIT_ZERO_FIRST (t)) | |
9ebe2ea3 | 1565 | init = build_zero_init (DECL_CONTEXT (fun), NULL_TREE, false); |
1566 | if (init) | |
1567 | { | |
1568 | tree op = get_nth_callarg (t, 0); | |
1569 | if (is_dummy_object (op)) | |
1570 | op = ctx->object; | |
1571 | else | |
1572 | op = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (op)), op); | |
1573 | tree set = build2 (MODIFY_EXPR, TREE_TYPE (op), op, init); | |
0ce12360 | 1574 | new_ctx.call = &new_call; |
1575 | return cxx_eval_constant_expression (&new_ctx, set, lval, | |
9ebe2ea3 | 1576 | non_constant_p, overflow_p); |
1577 | } | |
09b42213 | 1578 | } |
1579 | ||
8afcf831 | 1580 | /* We can't defer instantiating the function any longer. */ |
1581 | if (!DECL_INITIAL (fun) | |
1582 | && DECL_TEMPLOID_INSTANTIATION (fun)) | |
1583 | { | |
31db86df | 1584 | location_t save_loc = input_location; |
1585 | input_location = loc; | |
8afcf831 | 1586 | ++function_depth; |
1587 | instantiate_decl (fun, /*defer_ok*/false, /*expl_inst*/false); | |
1588 | --function_depth; | |
31db86df | 1589 | input_location = save_loc; |
8afcf831 | 1590 | } |
1591 | ||
09b42213 | 1592 | /* If in direct recursive call, optimize definition search. */ |
0ce12360 | 1593 | if (ctx && ctx->call && ctx->call->fundef && ctx->call->fundef->decl == fun) |
cf72f34d | 1594 | new_call.fundef = ctx->call->fundef; |
09b42213 | 1595 | else |
1596 | { | |
1597 | new_call.fundef = retrieve_constexpr_fundef (fun); | |
d2a9b1c1 | 1598 | if (new_call.fundef == NULL || new_call.fundef->body == NULL |
1599 | || fun == current_function_decl) | |
09b42213 | 1600 | { |
f83e6885 | 1601 | if (!ctx->quiet) |
09b42213 | 1602 | { |
d2a9b1c1 | 1603 | /* We need to check for current_function_decl here in case we're |
1604 | being called during cp_fold_function, because at that point | |
1605 | DECL_INITIAL is set properly and we have a fundef but we | |
1606 | haven't lowered invisirefs yet (c++/70344). */ | |
1607 | if (DECL_INITIAL (fun) == error_mark_node | |
1608 | || fun == current_function_decl) | |
a0efa758 | 1609 | error_at (loc, "%qD called in a constant expression before its " |
1610 | "definition is complete", fun); | |
1611 | else if (DECL_INITIAL (fun)) | |
09b42213 | 1612 | { |
33603066 | 1613 | /* The definition of fun was somehow unsuitable. But pretend |
1614 | that lambda static thunks don't exist. */ | |
1615 | if (!lambda_static_thunk_p (fun)) | |
1616 | error_at (loc, "%qD called in a constant expression", fun); | |
09b42213 | 1617 | explain_invalid_constexpr_fn (fun); |
1618 | } | |
1619 | else | |
1620 | error_at (loc, "%qD used before its definition", fun); | |
1621 | } | |
1622 | *non_constant_p = true; | |
1623 | return t; | |
1624 | } | |
1625 | } | |
9c96033c | 1626 | |
c8f6aeb1 | 1627 | bool non_constant_args = false; |
cf72f34d | 1628 | cxx_bind_parameters_in_call (ctx, t, &new_call, |
c8f6aeb1 | 1629 | non_constant_p, overflow_p, &non_constant_args); |
09b42213 | 1630 | if (*non_constant_p) |
1631 | return t; | |
1632 | ||
1633 | depth_ok = push_cx_call_context (t); | |
1634 | ||
c8f6aeb1 | 1635 | tree result = NULL_TREE; |
09b42213 | 1636 | |
c8f6aeb1 | 1637 | constexpr_call *entry = NULL; |
167a09fb | 1638 | if (depth_ok && !non_constant_args && ctx->strict) |
09b42213 | 1639 | { |
c8f6aeb1 | 1640 | new_call.hash = iterative_hash_template_arg |
1641 | (new_call.bindings, constexpr_fundef_hasher::hash (new_call.fundef)); | |
1642 | ||
1643 | /* If we have seen this call before, we are done. */ | |
1644 | maybe_initialize_constexpr_call_table (); | |
1645 | constexpr_call **slot | |
1646 | = constexpr_call_table->find_slot (&new_call, INSERT); | |
1647 | entry = *slot; | |
1648 | if (entry == NULL) | |
1649 | { | |
1650 | /* We need to keep a pointer to the entry, not just the slot, as the | |
1651 | slot can move in the call to cxx_eval_builtin_function_call. */ | |
1652 | *slot = entry = ggc_alloc<constexpr_call> (); | |
1653 | *entry = new_call; | |
1654 | } | |
2ba934c7 | 1655 | /* Calls that are in progress have their result set to NULL, |
c8f6aeb1 | 1656 | so that we can detect circular dependencies. */ |
1657 | else if (entry->result == NULL) | |
1658 | { | |
1659 | if (!ctx->quiet) | |
1660 | error ("call has circular dependency"); | |
1661 | *non_constant_p = true; | |
1662 | entry->result = result = error_mark_node; | |
1663 | } | |
1664 | else | |
1665 | result = entry->result; | |
09b42213 | 1666 | } |
1667 | ||
1668 | if (!depth_ok) | |
1669 | { | |
f83e6885 | 1670 | if (!ctx->quiet) |
5967b28b | 1671 | error ("%<constexpr%> evaluation depth exceeds maximum of %d (use " |
09b42213 | 1672 | "-fconstexpr-depth= to increase the maximum)", |
1673 | max_constexpr_depth); | |
1674 | *non_constant_p = true; | |
c8f6aeb1 | 1675 | result = error_mark_node; |
09b42213 | 1676 | } |
1677 | else | |
1678 | { | |
ab099088 | 1679 | if (result && result != error_mark_node) |
1680 | /* OK */; | |
1681 | else if (!DECL_SAVED_TREE (fun)) | |
1682 | { | |
1683 | /* When at_eof >= 2, cgraph has started throwing away | |
1684 | DECL_SAVED_TREE, so fail quietly. FIXME we get here because of | |
1685 | late code generation for VEC_INIT_EXPR, which needs to be | |
1686 | completely reconsidered. */ | |
1687 | gcc_assert (at_eof >= 2 && ctx->quiet); | |
1688 | *non_constant_p = true; | |
1689 | } | |
1690 | else | |
cf72f34d | 1691 | { |
4f7ebe46 | 1692 | tree body, parms, res; |
88a59139 | 1693 | |
4f7ebe46 | 1694 | /* Reuse or create a new unshared copy of this function's body. */ |
a050099a | 1695 | tree copy = get_fundef_copy (fun); |
1696 | body = TREE_PURPOSE (copy); | |
1697 | parms = TREE_VALUE (copy); | |
1698 | res = TREE_TYPE (copy); | |
88a59139 | 1699 | |
1700 | /* Associate the bindings with the remapped parms. */ | |
1701 | tree bound = new_call.bindings; | |
1702 | tree remapped = parms; | |
1703 | while (bound) | |
9c96033c | 1704 | { |
88a59139 | 1705 | tree oparm = TREE_PURPOSE (bound); |
1706 | tree arg = TREE_VALUE (bound); | |
1707 | gcc_assert (DECL_NAME (remapped) == DECL_NAME (oparm)); | |
5898f0d7 | 1708 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 1709 | arg = unshare_constructor (arg); |
88a59139 | 1710 | ctx->values->put (remapped, arg); |
1711 | bound = TREE_CHAIN (bound); | |
1712 | remapped = DECL_CHAIN (remapped); | |
9c96033c | 1713 | } |
88a59139 | 1714 | /* Add the RESULT_DECL to the values map, too. */ |
1715 | tree slot = NULL_TREE; | |
1716 | if (DECL_BY_REFERENCE (res)) | |
9c96033c | 1717 | { |
88a59139 | 1718 | slot = AGGR_INIT_EXPR_SLOT (t); |
1719 | tree addr = build_address (slot); | |
1720 | addr = build_nop (TREE_TYPE (res), addr); | |
1721 | ctx->values->put (res, addr); | |
1722 | ctx->values->put (slot, NULL_TREE); | |
1723 | } | |
1724 | else | |
1725 | ctx->values->put (res, NULL_TREE); | |
9c96033c | 1726 | |
4f7ebe46 | 1727 | /* Track the callee's evaluated SAVE_EXPRs so that we can forget |
1728 | their values after the call. */ | |
1729 | constexpr_ctx ctx_with_save_exprs = *ctx; | |
1730 | hash_set<tree> save_exprs; | |
1731 | ctx_with_save_exprs.save_exprs = &save_exprs; | |
43b7271d | 1732 | ctx_with_save_exprs.call = &new_call; |
4f7ebe46 | 1733 | |
88a59139 | 1734 | tree jump_target = NULL_TREE; |
4f7ebe46 | 1735 | cxx_eval_constant_expression (&ctx_with_save_exprs, body, |
88a59139 | 1736 | lval, non_constant_p, overflow_p, |
1737 | &jump_target); | |
9c96033c | 1738 | |
88a59139 | 1739 | if (DECL_CONSTRUCTOR_P (fun)) |
1740 | /* This can be null for a subobject constructor call, in | |
1741 | which case what we care about is the initialization | |
1742 | side-effects rather than the value. We could get at the | |
1743 | value by evaluating *this, but we don't bother; there's | |
1744 | no need to put such a call in the hash table. */ | |
1745 | result = lval ? ctx->object : ctx->ctor; | |
1746 | else if (VOID_TYPE_P (TREE_TYPE (res))) | |
1747 | result = void_node; | |
1748 | else | |
1749 | { | |
1750 | result = *ctx->values->get (slot ? slot : res); | |
1751 | if (result == NULL_TREE && !*non_constant_p) | |
9c96033c | 1752 | { |
88a59139 | 1753 | if (!ctx->quiet) |
5967b28b | 1754 | error ("%<constexpr%> call flows off the end " |
88a59139 | 1755 | "of the function"); |
1756 | *non_constant_p = true; | |
9c96033c | 1757 | } |
9c96033c | 1758 | } |
88a59139 | 1759 | |
4f7ebe46 | 1760 | /* Forget the saved values of the callee's SAVE_EXPRs. */ |
1761 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
1762 | iter != save_exprs.end(); ++iter) | |
1763 | ctx_with_save_exprs.values->remove (*iter); | |
1764 | ||
88a59139 | 1765 | /* Remove the parms/result from the values map. Is it worth |
1766 | bothering to do this when the map itself is only live for | |
1767 | one constexpr evaluation? If so, maybe also clear out | |
1768 | other vars from call, maybe in BIND_EXPR handling? */ | |
1769 | ctx->values->remove (res); | |
1770 | if (slot) | |
1771 | ctx->values->remove (slot); | |
1772 | for (tree parm = parms; parm; parm = TREE_CHAIN (parm)) | |
1773 | ctx->values->remove (parm); | |
4f7ebe46 | 1774 | |
1775 | /* Make the unshared function copy we used available for re-use. */ | |
1776 | save_fundef_copy (fun, copy); | |
cf72f34d | 1777 | } |
9c96033c | 1778 | |
09b42213 | 1779 | if (result == error_mark_node) |
1780 | *non_constant_p = true; | |
c3f376bf | 1781 | if (*non_constant_p || *overflow_p) |
c8f6aeb1 | 1782 | result = error_mark_node; |
88a59139 | 1783 | else if (!result) |
9c96033c | 1784 | result = void_node; |
c8f6aeb1 | 1785 | if (entry) |
1786 | entry->result = result; | |
09b42213 | 1787 | } |
1788 | ||
c6d97004 | 1789 | /* The result of a constexpr function must be completely initialized. */ |
1790 | if (TREE_CODE (result) == CONSTRUCTOR) | |
79cdb4f5 | 1791 | clear_no_implicit_zero (result); |
c6d97004 | 1792 | |
09b42213 | 1793 | pop_cx_call_context (); |
e283bb4f | 1794 | return unshare_constructor (result); |
09b42213 | 1795 | } |
1796 | ||
1797 | /* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */ | |
1798 | ||
1799 | bool | |
1800 | reduced_constant_expression_p (tree t) | |
1801 | { | |
a34934c2 | 1802 | if (t == NULL_TREE) |
1803 | return false; | |
1804 | ||
09b42213 | 1805 | switch (TREE_CODE (t)) |
1806 | { | |
1807 | case PTRMEM_CST: | |
1808 | /* Even if we can't lower this yet, it's constant. */ | |
1809 | return true; | |
1810 | ||
1811 | case CONSTRUCTOR: | |
1812 | /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */ | |
56da7fe6 | 1813 | tree idx, val, field; unsigned HOST_WIDE_INT i; |
165d0d5b | 1814 | if (CONSTRUCTOR_NO_CLEARING (t)) |
c4210852 | 1815 | { |
1816 | if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE) | |
1817 | /* An initialized vector would have a VECTOR_CST. */ | |
1818 | return false; | |
1819 | else | |
1820 | field = next_initializable_field (TYPE_FIELDS (TREE_TYPE (t))); | |
1821 | } | |
56da7fe6 | 1822 | else |
1823 | field = NULL_TREE; | |
1824 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t), i, idx, val) | |
ce4ffd9e | 1825 | { |
a34934c2 | 1826 | /* If VAL is null, we're in the middle of initializing this |
1827 | element. */ | |
56da7fe6 | 1828 | if (!reduced_constant_expression_p (val)) |
ce4ffd9e | 1829 | return false; |
56da7fe6 | 1830 | if (field) |
1831 | { | |
1832 | if (idx != field) | |
1833 | return false; | |
1834 | field = next_initializable_field (DECL_CHAIN (field)); | |
1835 | } | |
ce4ffd9e | 1836 | } |
56da7fe6 | 1837 | if (field) |
1838 | return false; | |
165d0d5b | 1839 | else if (CONSTRUCTOR_NO_CLEARING (t)) |
56da7fe6 | 1840 | /* All the fields are initialized. */ |
165d0d5b | 1841 | CONSTRUCTOR_NO_CLEARING (t) = false; |
09b42213 | 1842 | return true; |
1843 | ||
1844 | default: | |
1845 | /* FIXME are we calling this too much? */ | |
1846 | return initializer_constant_valid_p (t, TREE_TYPE (t)) != NULL_TREE; | |
1847 | } | |
1848 | } | |
1849 | ||
1850 | /* Some expressions may have constant operands but are not constant | |
941fafa5 | 1851 | themselves, such as 1/0. Call this function to check for that |
1852 | condition. | |
09b42213 | 1853 | |
1854 | We only call this in places that require an arithmetic constant, not in | |
1855 | places where we might have a non-constant expression that can be a | |
1856 | component of a constant expression, such as the address of a constexpr | |
1857 | variable that might be dereferenced later. */ | |
1858 | ||
1859 | static bool | |
1860 | verify_constant (tree t, bool allow_non_constant, bool *non_constant_p, | |
1861 | bool *overflow_p) | |
1862 | { | |
1863 | if (!*non_constant_p && !reduced_constant_expression_p (t)) | |
1864 | { | |
1865 | if (!allow_non_constant) | |
1866 | error ("%q+E is not a constant expression", t); | |
1867 | *non_constant_p = true; | |
1868 | } | |
1869 | if (TREE_OVERFLOW_P (t)) | |
1870 | { | |
1871 | if (!allow_non_constant) | |
1872 | { | |
1873 | permerror (input_location, "overflow in constant expression"); | |
1874 | /* If we're being permissive (and are in an enforcing | |
1875 | context), ignore the overflow. */ | |
1876 | if (flag_permissive) | |
1877 | return *non_constant_p; | |
1878 | } | |
1879 | *overflow_p = true; | |
1880 | } | |
1881 | return *non_constant_p; | |
1882 | } | |
1883 | ||
2b035ffe | 1884 | /* Check whether the shift operation with code CODE and type TYPE on LHS |
1885 | and RHS is undefined. If it is, give an error with an explanation, | |
1886 | and return true; return false otherwise. */ | |
1887 | ||
1888 | static bool | |
1889 | cxx_eval_check_shift_p (location_t loc, const constexpr_ctx *ctx, | |
1890 | enum tree_code code, tree type, tree lhs, tree rhs) | |
1891 | { | |
1892 | if ((code != LSHIFT_EXPR && code != RSHIFT_EXPR) | |
1893 | || TREE_CODE (lhs) != INTEGER_CST | |
1894 | || TREE_CODE (rhs) != INTEGER_CST) | |
1895 | return false; | |
1896 | ||
1897 | tree lhstype = TREE_TYPE (lhs); | |
1898 | unsigned HOST_WIDE_INT uprec = TYPE_PRECISION (TREE_TYPE (lhs)); | |
1899 | ||
1900 | /* [expr.shift] The behavior is undefined if the right operand | |
1901 | is negative, or greater than or equal to the length in bits | |
1902 | of the promoted left operand. */ | |
1903 | if (tree_int_cst_sgn (rhs) == -1) | |
1904 | { | |
1905 | if (!ctx->quiet) | |
91d87e22 | 1906 | permerror (loc, "right operand of shift expression %q+E is negative", |
1907 | build2_loc (loc, code, type, lhs, rhs)); | |
1908 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1909 | } |
1910 | if (compare_tree_int (rhs, uprec) >= 0) | |
1911 | { | |
1912 | if (!ctx->quiet) | |
91d87e22 | 1913 | permerror (loc, "right operand of shift expression %q+E is >= than " |
1914 | "the precision of the left operand", | |
1915 | build2_loc (loc, code, type, lhs, rhs)); | |
1916 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1917 | } |
1918 | ||
1919 | /* The value of E1 << E2 is E1 left-shifted E2 bit positions; [...] | |
1920 | if E1 has a signed type and non-negative value, and E1x2^E2 is | |
1921 | representable in the corresponding unsigned type of the result type, | |
1922 | then that value, converted to the result type, is the resulting value; | |
1923 | otherwise, the behavior is undefined. */ | |
1924 | if (code == LSHIFT_EXPR && !TYPE_UNSIGNED (lhstype) | |
1925 | && (cxx_dialect >= cxx11)) | |
1926 | { | |
1927 | if (tree_int_cst_sgn (lhs) == -1) | |
1928 | { | |
1929 | if (!ctx->quiet) | |
91d87e22 | 1930 | permerror (loc, |
1931 | "left operand of shift expression %q+E is negative", | |
1932 | build2_loc (loc, code, type, lhs, rhs)); | |
1933 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1934 | } |
1935 | /* For signed x << y the following: | |
1936 | (unsigned) x >> ((prec (lhs) - 1) - y) | |
1937 | if > 1, is undefined. The right-hand side of this formula | |
1938 | is the highest bit of the LHS that can be set (starting from 0), | |
1939 | so that the shift doesn't overflow. We then right-shift the LHS | |
1940 | to see whether any other bit is set making the original shift | |
1941 | undefined -- the result is not representable in the corresponding | |
1942 | unsigned type. */ | |
1943 | tree t = build_int_cst (unsigned_type_node, uprec - 1); | |
1944 | t = fold_build2 (MINUS_EXPR, unsigned_type_node, t, rhs); | |
1945 | tree ulhs = fold_convert (unsigned_type_for (lhstype), lhs); | |
1946 | t = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ulhs), ulhs, t); | |
1947 | if (tree_int_cst_lt (integer_one_node, t)) | |
1948 | { | |
1949 | if (!ctx->quiet) | |
91d87e22 | 1950 | permerror (loc, "shift expression %q+E overflows", |
1951 | build2_loc (loc, code, type, lhs, rhs)); | |
1952 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1953 | } |
1954 | } | |
1955 | return false; | |
1956 | } | |
1957 | ||
09b42213 | 1958 | /* Subroutine of cxx_eval_constant_expression. |
1959 | Attempt to reduce the unary expression tree T to a compile time value. | |
1960 | If successful, return the value. Otherwise issue a diagnostic | |
1961 | and return error_mark_node. */ | |
1962 | ||
1963 | static tree | |
cf72f34d | 1964 | cxx_eval_unary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 1965 | bool /*lval*/, |
09b42213 | 1966 | bool *non_constant_p, bool *overflow_p) |
1967 | { | |
1968 | tree r; | |
1969 | tree orig_arg = TREE_OPERAND (t, 0); | |
c8f6aeb1 | 1970 | tree arg = cxx_eval_constant_expression (ctx, orig_arg, /*lval*/false, |
1971 | non_constant_p, overflow_p); | |
09b42213 | 1972 | VERIFY_CONSTANT (arg); |
93add516 | 1973 | location_t loc = EXPR_LOCATION (t); |
1974 | enum tree_code code = TREE_CODE (t); | |
1975 | tree type = TREE_TYPE (t); | |
1976 | r = fold_unary_loc (loc, code, type, arg); | |
1977 | if (r == NULL_TREE) | |
1978 | { | |
1979 | if (arg == orig_arg) | |
1980 | r = t; | |
1981 | else | |
1982 | r = build1_loc (loc, code, type, arg); | |
1983 | } | |
09b42213 | 1984 | VERIFY_CONSTANT (r); |
1985 | return r; | |
1986 | } | |
1987 | ||
46fad8d5 | 1988 | /* Helper function for cxx_eval_binary_expression. Try to optimize |
1989 | original POINTER_PLUS_EXPR T, LHS p+ RHS, return NULL_TREE if the | |
1990 | generic folding should be used. */ | |
1991 | ||
1992 | static tree | |
1993 | cxx_fold_pointer_plus_expression (const constexpr_ctx *ctx, tree t, | |
1994 | tree lhs, tree rhs, bool *non_constant_p, | |
1995 | bool *overflow_p) | |
1996 | { | |
1997 | STRIP_NOPS (lhs); | |
1998 | if (TREE_CODE (lhs) != ADDR_EXPR) | |
1999 | return NULL_TREE; | |
2000 | ||
2001 | lhs = TREE_OPERAND (lhs, 0); | |
2002 | ||
2003 | /* &A[i] p+ j => &A[i + j] */ | |
2004 | if (TREE_CODE (lhs) == ARRAY_REF | |
2005 | && TREE_CODE (TREE_OPERAND (lhs, 1)) == INTEGER_CST | |
2006 | && TREE_CODE (rhs) == INTEGER_CST | |
2007 | && TYPE_SIZE_UNIT (TREE_TYPE (lhs)) | |
2008 | && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (lhs))) == INTEGER_CST) | |
2009 | { | |
2010 | tree orig_type = TREE_TYPE (t); | |
2011 | location_t loc = EXPR_LOCATION (t); | |
2012 | tree type = TREE_TYPE (lhs); | |
2013 | ||
2014 | t = fold_convert_loc (loc, ssizetype, TREE_OPERAND (lhs, 1)); | |
2015 | tree nelts = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (lhs, 0))); | |
2016 | nelts = cxx_eval_constant_expression (ctx, nelts, false, non_constant_p, | |
2017 | overflow_p); | |
2018 | if (*non_constant_p) | |
2019 | return NULL_TREE; | |
2020 | /* Don't fold an out-of-bound access. */ | |
2021 | if (!tree_int_cst_le (t, nelts)) | |
2022 | return NULL_TREE; | |
2023 | rhs = cp_fold_convert (ssizetype, rhs); | |
2024 | /* Don't fold if rhs can't be divided exactly by TYPE_SIZE_UNIT. | |
2025 | constexpr int A[1]; ... (char *)&A[0] + 1 */ | |
2026 | if (!integer_zerop (fold_build2_loc (loc, TRUNC_MOD_EXPR, sizetype, | |
2027 | rhs, TYPE_SIZE_UNIT (type)))) | |
2028 | return NULL_TREE; | |
2029 | /* Make sure to treat the second operand of POINTER_PLUS_EXPR | |
2030 | as signed. */ | |
2031 | rhs = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, rhs, | |
2032 | TYPE_SIZE_UNIT (type)); | |
2033 | t = size_binop_loc (loc, PLUS_EXPR, rhs, t); | |
2034 | t = build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (lhs, 0), | |
2035 | t, NULL_TREE, NULL_TREE); | |
2036 | t = cp_build_addr_expr (t, tf_warning_or_error); | |
2037 | t = cp_fold_convert (orig_type, t); | |
2038 | return cxx_eval_constant_expression (ctx, t, /*lval*/false, | |
2039 | non_constant_p, overflow_p); | |
2040 | } | |
2041 | ||
2042 | return NULL_TREE; | |
2043 | } | |
2044 | ||
09b42213 | 2045 | /* Subroutine of cxx_eval_constant_expression. |
2046 | Like cxx_eval_unary_expression, except for binary expressions. */ | |
2047 | ||
2048 | static tree | |
cf72f34d | 2049 | cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 2050 | bool /*lval*/, |
09b42213 | 2051 | bool *non_constant_p, bool *overflow_p) |
2052 | { | |
f7ef5392 | 2053 | tree r = NULL_TREE; |
09b42213 | 2054 | tree orig_lhs = TREE_OPERAND (t, 0); |
2055 | tree orig_rhs = TREE_OPERAND (t, 1); | |
2056 | tree lhs, rhs; | |
c8f6aeb1 | 2057 | lhs = cxx_eval_constant_expression (ctx, orig_lhs, /*lval*/false, |
b2a43197 | 2058 | non_constant_p, overflow_p); |
6d6737d9 | 2059 | /* Don't VERIFY_CONSTANT here, it's unnecessary and will break pointer |
2060 | subtraction. */ | |
2061 | if (*non_constant_p) | |
2062 | return t; | |
c8f6aeb1 | 2063 | rhs = cxx_eval_constant_expression (ctx, orig_rhs, /*lval*/false, |
b2a43197 | 2064 | non_constant_p, overflow_p); |
6d6737d9 | 2065 | if (*non_constant_p) |
2066 | return t; | |
93add516 | 2067 | |
2068 | location_t loc = EXPR_LOCATION (t); | |
2069 | enum tree_code code = TREE_CODE (t); | |
2070 | tree type = TREE_TYPE (t); | |
f7ef5392 | 2071 | |
2072 | if (code == EQ_EXPR || code == NE_EXPR) | |
2073 | { | |
2074 | bool is_code_eq = (code == EQ_EXPR); | |
2075 | ||
2076 | if (TREE_CODE (lhs) == PTRMEM_CST | |
2077 | && TREE_CODE (rhs) == PTRMEM_CST) | |
e9f29fe5 | 2078 | { |
2079 | tree lmem = PTRMEM_CST_MEMBER (lhs); | |
2080 | tree rmem = PTRMEM_CST_MEMBER (rhs); | |
2081 | bool eq; | |
2082 | if (TREE_CODE (lmem) == TREE_CODE (rmem) | |
2083 | && TREE_CODE (lmem) == FIELD_DECL | |
2084 | && TREE_CODE (DECL_CONTEXT (lmem)) == UNION_TYPE | |
2085 | && same_type_p (DECL_CONTEXT (lmem), | |
2086 | DECL_CONTEXT (rmem))) | |
2087 | /* If both refer to (possibly different) members of the same union | |
2088 | (12.3), they compare equal. */ | |
2089 | eq = true; | |
2090 | else | |
2091 | eq = cp_tree_equal (lhs, rhs); | |
2092 | r = constant_boolean_node (eq == is_code_eq, type); | |
2093 | } | |
f7ef5392 | 2094 | else if ((TREE_CODE (lhs) == PTRMEM_CST |
2095 | || TREE_CODE (rhs) == PTRMEM_CST) | |
2096 | && (null_member_pointer_value_p (lhs) | |
2097 | || null_member_pointer_value_p (rhs))) | |
2098 | r = constant_boolean_node (!is_code_eq, type); | |
f31f4e9c | 2099 | else if (TREE_CODE (lhs) == PTRMEM_CST) |
2100 | lhs = cplus_expand_constant (lhs); | |
2101 | else if (TREE_CODE (rhs) == PTRMEM_CST) | |
2102 | rhs = cplus_expand_constant (rhs); | |
f7ef5392 | 2103 | } |
cb768824 | 2104 | if (code == POINTER_PLUS_EXPR && !*non_constant_p |
2105 | && integer_zerop (lhs) && !integer_zerop (rhs)) | |
2106 | { | |
2107 | if (!ctx->quiet) | |
2108 | error ("arithmetic involving a null pointer in %qE", lhs); | |
2b1749c4 | 2109 | *non_constant_p = true; |
cb768824 | 2110 | return t; |
2111 | } | |
46fad8d5 | 2112 | else if (code == POINTER_PLUS_EXPR) |
2113 | r = cxx_fold_pointer_plus_expression (ctx, t, lhs, rhs, non_constant_p, | |
2114 | overflow_p); | |
f7ef5392 | 2115 | |
2116 | if (r == NULL_TREE) | |
2117 | r = fold_binary_loc (loc, code, type, lhs, rhs); | |
2118 | ||
93add516 | 2119 | if (r == NULL_TREE) |
2120 | { | |
2121 | if (lhs == orig_lhs && rhs == orig_rhs) | |
2122 | r = t; | |
2123 | else | |
2124 | r = build2_loc (loc, code, type, lhs, rhs); | |
2125 | } | |
2b035ffe | 2126 | else if (cxx_eval_check_shift_p (loc, ctx, code, type, lhs, rhs)) |
2127 | *non_constant_p = true; | |
6d6737d9 | 2128 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
2129 | a local array in a constexpr function. */ | |
d03fa520 | 2130 | bool ptr = INDIRECT_TYPE_P (TREE_TYPE (lhs)); |
35f2c28f | 2131 | if (!ptr) |
aae7465c | 2132 | VERIFY_CONSTANT (r); |
09b42213 | 2133 | return r; |
2134 | } | |
2135 | ||
2136 | /* Subroutine of cxx_eval_constant_expression. | |
2137 | Attempt to evaluate condition expressions. Dead branches are not | |
2138 | looked into. */ | |
2139 | ||
2140 | static tree | |
cf72f34d | 2141 | cxx_eval_conditional_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2142 | bool lval, |
00f21715 | 2143 | bool *non_constant_p, bool *overflow_p, |
2144 | tree *jump_target) | |
09b42213 | 2145 | { |
cf72f34d | 2146 | tree val = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
c8f6aeb1 | 2147 | /*lval*/false, |
b2a43197 | 2148 | non_constant_p, overflow_p); |
09b42213 | 2149 | VERIFY_CONSTANT (val); |
2150 | /* Don't VERIFY_CONSTANT the other operands. */ | |
2151 | if (integer_zerop (val)) | |
cf72f34d | 2152 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), |
1227ba74 | 2153 | lval, |
00f21715 | 2154 | non_constant_p, overflow_p, |
2155 | jump_target); | |
cf72f34d | 2156 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2157 | lval, |
00f21715 | 2158 | non_constant_p, overflow_p, |
2159 | jump_target); | |
09b42213 | 2160 | } |
2161 | ||
31595caf | 2162 | /* Subroutine of cxx_eval_constant_expression. |
2163 | Attempt to evaluate vector condition expressions. Unlike | |
2164 | cxx_eval_conditional_expression, VEC_COND_EXPR acts like a normal | |
2165 | ternary arithmetics operation, where all 3 arguments have to be | |
2166 | evaluated as constants and then folding computes the result from | |
2167 | them. */ | |
2168 | ||
2169 | static tree | |
2170 | cxx_eval_vector_conditional_expression (const constexpr_ctx *ctx, tree t, | |
2171 | bool *non_constant_p, bool *overflow_p) | |
2172 | { | |
2173 | tree arg1 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
2174 | /*lval*/false, | |
2175 | non_constant_p, overflow_p); | |
2176 | VERIFY_CONSTANT (arg1); | |
2177 | tree arg2 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
2178 | /*lval*/false, | |
2179 | non_constant_p, overflow_p); | |
2180 | VERIFY_CONSTANT (arg2); | |
2181 | tree arg3 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
2182 | /*lval*/false, | |
2183 | non_constant_p, overflow_p); | |
2184 | VERIFY_CONSTANT (arg3); | |
2185 | location_t loc = EXPR_LOCATION (t); | |
2186 | tree type = TREE_TYPE (t); | |
2187 | tree r = fold_ternary_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2188 | if (r == NULL_TREE) | |
2189 | { | |
2190 | if (arg1 == TREE_OPERAND (t, 0) | |
2191 | && arg2 == TREE_OPERAND (t, 1) | |
2192 | && arg3 == TREE_OPERAND (t, 2)) | |
2193 | r = t; | |
2194 | else | |
2195 | r = build3_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2196 | } | |
2197 | VERIFY_CONSTANT (r); | |
2198 | return r; | |
2199 | } | |
2200 | ||
7963b19d | 2201 | /* Returns less than, equal to, or greater than zero if KEY is found to be |
2202 | less than, to match, or to be greater than the constructor_elt's INDEX. */ | |
2203 | ||
2204 | static int | |
2205 | array_index_cmp (tree key, tree index) | |
2206 | { | |
2207 | gcc_assert (TREE_CODE (key) == INTEGER_CST); | |
2208 | ||
2209 | switch (TREE_CODE (index)) | |
2210 | { | |
2211 | case INTEGER_CST: | |
2212 | return tree_int_cst_compare (key, index); | |
2213 | case RANGE_EXPR: | |
2214 | { | |
2215 | tree lo = TREE_OPERAND (index, 0); | |
2216 | tree hi = TREE_OPERAND (index, 1); | |
2217 | if (tree_int_cst_lt (key, lo)) | |
2218 | return -1; | |
2219 | else if (tree_int_cst_lt (hi, key)) | |
2220 | return 1; | |
2221 | else | |
2222 | return 0; | |
2223 | } | |
2224 | default: | |
2225 | gcc_unreachable (); | |
2226 | } | |
2227 | } | |
2228 | ||
2229 | /* Returns the index of the constructor_elt of ARY which matches DINDEX, or -1 | |
2230 | if none. If INSERT is true, insert a matching element rather than fail. */ | |
2231 | ||
2232 | static HOST_WIDE_INT | |
2233 | find_array_ctor_elt (tree ary, tree dindex, bool insert = false) | |
2234 | { | |
2235 | if (tree_int_cst_sgn (dindex) < 0) | |
2236 | return -1; | |
2237 | ||
2238 | unsigned HOST_WIDE_INT i = tree_to_uhwi (dindex); | |
2239 | vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (ary); | |
2240 | unsigned HOST_WIDE_INT len = vec_safe_length (elts); | |
2241 | ||
2242 | unsigned HOST_WIDE_INT end = len; | |
2243 | unsigned HOST_WIDE_INT begin = 0; | |
2244 | ||
2245 | /* If the last element of the CONSTRUCTOR has its own index, we can assume | |
2246 | that the same is true of the other elements and index directly. */ | |
2247 | if (end > 0) | |
2248 | { | |
e99466d6 | 2249 | tree cindex = (*elts)[end - 1].index; |
7963b19d | 2250 | if (TREE_CODE (cindex) == INTEGER_CST |
e99466d6 | 2251 | && compare_tree_int (cindex, end - 1) == 0) |
7963b19d | 2252 | { |
2253 | if (i < end) | |
2254 | return i; | |
2255 | else | |
2256 | begin = end; | |
2257 | } | |
2258 | } | |
2259 | ||
2260 | /* Otherwise, find a matching index by means of a binary search. */ | |
2261 | while (begin != end) | |
2262 | { | |
2263 | unsigned HOST_WIDE_INT middle = (begin + end) / 2; | |
f0b916c7 | 2264 | constructor_elt &elt = (*elts)[middle]; |
2265 | tree idx = elt.index; | |
7963b19d | 2266 | |
f0b916c7 | 2267 | int cmp = array_index_cmp (dindex, idx); |
7963b19d | 2268 | if (cmp < 0) |
2269 | end = middle; | |
2270 | else if (cmp > 0) | |
2271 | begin = middle + 1; | |
2272 | else | |
f0b916c7 | 2273 | { |
2274 | if (insert && TREE_CODE (idx) == RANGE_EXPR) | |
2275 | { | |
2276 | /* We need to split the range. */ | |
2277 | constructor_elt e; | |
2278 | tree lo = TREE_OPERAND (idx, 0); | |
2279 | tree hi = TREE_OPERAND (idx, 1); | |
e99466d6 | 2280 | tree value = elt.value; |
2281 | dindex = fold_convert (sizetype, dindex); | |
f0b916c7 | 2282 | if (tree_int_cst_lt (lo, dindex)) |
2283 | { | |
2284 | /* There are still some lower elts; shorten the range. */ | |
2285 | tree new_hi = int_const_binop (MINUS_EXPR, dindex, | |
2286 | size_one_node); | |
2287 | if (tree_int_cst_equal (lo, new_hi)) | |
2288 | /* Only one element left, no longer a range. */ | |
2289 | elt.index = lo; | |
2290 | else | |
2291 | TREE_OPERAND (idx, 1) = new_hi; | |
2292 | /* Append the element we want to insert. */ | |
2293 | ++middle; | |
2294 | e.index = dindex; | |
e99466d6 | 2295 | e.value = unshare_constructor (value); |
f0b916c7 | 2296 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle, e); |
2297 | } | |
2298 | else | |
2299 | /* No lower elts, the range elt is now ours. */ | |
2300 | elt.index = dindex; | |
2301 | ||
2302 | if (tree_int_cst_lt (dindex, hi)) | |
2303 | { | |
2304 | /* There are still some higher elts; append a range. */ | |
2305 | tree new_lo = int_const_binop (PLUS_EXPR, dindex, | |
2306 | size_one_node); | |
2307 | if (tree_int_cst_equal (new_lo, hi)) | |
2308 | e.index = hi; | |
2309 | else | |
2310 | e.index = build2 (RANGE_EXPR, sizetype, new_lo, hi); | |
e99466d6 | 2311 | e.value = unshare_constructor (value); |
2312 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle + 1, e); | |
f0b916c7 | 2313 | } |
2314 | } | |
2315 | return middle; | |
2316 | } | |
7963b19d | 2317 | } |
2318 | ||
2319 | if (insert) | |
2320 | { | |
2321 | constructor_elt e = { dindex, NULL_TREE }; | |
2322 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), end, e); | |
2323 | return end; | |
2324 | } | |
2325 | ||
2326 | return -1; | |
2327 | } | |
2328 | ||
40df9099 | 2329 | /* Under the control of CTX, issue a detailed diagnostic for |
2330 | an out-of-bounds subscript INDEX into the expression ARRAY. */ | |
2331 | ||
2332 | static void | |
2333 | diag_array_subscript (const constexpr_ctx *ctx, tree array, tree index) | |
2334 | { | |
2335 | if (!ctx->quiet) | |
2336 | { | |
2337 | tree arraytype = TREE_TYPE (array); | |
2338 | ||
2339 | /* Convert the unsigned array subscript to a signed integer to avoid | |
2340 | printing huge numbers for small negative values. */ | |
2341 | tree sidx = fold_convert (ssizetype, index); | |
2342 | if (DECL_P (array)) | |
2343 | { | |
d7d265db | 2344 | if (TYPE_DOMAIN (arraytype)) |
2345 | error ("array subscript value %qE is outside the bounds " | |
2346 | "of array %qD of type %qT", sidx, array, arraytype); | |
2347 | else | |
2348 | error ("non-zero array subscript %qE is used with array %qD of " | |
2349 | "type %qT with unknown bounds", sidx, array, arraytype); | |
40df9099 | 2350 | inform (DECL_SOURCE_LOCATION (array), "declared here"); |
2351 | } | |
d7d265db | 2352 | else if (TYPE_DOMAIN (arraytype)) |
40df9099 | 2353 | error ("array subscript value %qE is outside the bounds " |
2354 | "of array type %qT", sidx, arraytype); | |
d7d265db | 2355 | else |
2356 | error ("non-zero array subscript %qE is used with array of type %qT " | |
2357 | "with unknown bounds", sidx, arraytype); | |
40df9099 | 2358 | } |
2359 | } | |
7963b19d | 2360 | |
51f0c7e2 | 2361 | /* Return the number of elements for TYPE (which is an ARRAY_TYPE or |
2362 | a VECTOR_TYPE). */ | |
2363 | ||
2364 | static tree | |
2365 | get_array_or_vector_nelts (const constexpr_ctx *ctx, tree type, | |
2366 | bool *non_constant_p, bool *overflow_p) | |
2367 | { | |
2368 | tree nelts; | |
2369 | if (TREE_CODE (type) == ARRAY_TYPE) | |
2370 | { | |
2371 | if (TYPE_DOMAIN (type)) | |
2372 | nelts = array_type_nelts_top (type); | |
2373 | else | |
2374 | nelts = size_zero_node; | |
2375 | } | |
2376 | else if (VECTOR_TYPE_P (type)) | |
2377 | nelts = size_int (TYPE_VECTOR_SUBPARTS (type)); | |
2378 | else | |
2379 | gcc_unreachable (); | |
2380 | ||
2381 | /* For VLAs, the number of elements won't be an integer constant. */ | |
2382 | nelts = cxx_eval_constant_expression (ctx, nelts, false, | |
2383 | non_constant_p, overflow_p); | |
2384 | return nelts; | |
2385 | } | |
2386 | ||
92fe8840 | 2387 | /* Extract element INDEX consisting of CHARS_PER_ELT chars from |
2388 | STRING_CST STRING. */ | |
2389 | ||
2390 | static tree | |
2391 | extract_string_elt (tree string, unsigned chars_per_elt, unsigned index) | |
2392 | { | |
2393 | tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (string))); | |
2394 | tree r; | |
2395 | ||
2396 | if (chars_per_elt == 1) | |
2397 | r = build_int_cst (type, TREE_STRING_POINTER (string)[index]); | |
2398 | else | |
2399 | { | |
2400 | const unsigned char *ptr | |
2401 | = ((const unsigned char *)TREE_STRING_POINTER (string) | |
2402 | + index * chars_per_elt); | |
2403 | r = native_interpret_expr (type, ptr, chars_per_elt); | |
2404 | } | |
2405 | return r; | |
2406 | } | |
2407 | ||
09b42213 | 2408 | /* Subroutine of cxx_eval_constant_expression. |
2409 | Attempt to reduce a reference to an array slot. */ | |
2410 | ||
2411 | static tree | |
cf72f34d | 2412 | cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2413 | bool lval, |
09b42213 | 2414 | bool *non_constant_p, bool *overflow_p) |
2415 | { | |
2416 | tree oldary = TREE_OPERAND (t, 0); | |
cf72f34d | 2417 | tree ary = cxx_eval_constant_expression (ctx, oldary, |
1227ba74 | 2418 | lval, |
b2a43197 | 2419 | non_constant_p, overflow_p); |
09b42213 | 2420 | tree index, oldidx; |
cf3cefc9 | 2421 | HOST_WIDE_INT i = 0; |
2422 | tree elem_type = NULL_TREE; | |
2423 | unsigned len = 0, elem_nchars = 1; | |
09b42213 | 2424 | if (*non_constant_p) |
2425 | return t; | |
2426 | oldidx = TREE_OPERAND (t, 1); | |
cf72f34d | 2427 | index = cxx_eval_constant_expression (ctx, oldidx, |
f83e6885 | 2428 | false, |
b2a43197 | 2429 | non_constant_p, overflow_p); |
09b42213 | 2430 | VERIFY_CONSTANT (index); |
cf3cefc9 | 2431 | if (!lval) |
09b42213 | 2432 | { |
cf3cefc9 | 2433 | elem_type = TREE_TYPE (TREE_TYPE (ary)); |
2434 | if (TREE_CODE (ary) == VIEW_CONVERT_EXPR | |
2435 | && VECTOR_TYPE_P (TREE_TYPE (TREE_OPERAND (ary, 0))) | |
2436 | && TREE_TYPE (t) == TREE_TYPE (TREE_TYPE (TREE_OPERAND (ary, 0)))) | |
2437 | ary = TREE_OPERAND (ary, 0); | |
2438 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2439 | len = CONSTRUCTOR_NELTS (ary); | |
2440 | else if (TREE_CODE (ary) == STRING_CST) | |
2441 | { | |
2442 | elem_nchars = (TYPE_PRECISION (elem_type) | |
2443 | / TYPE_PRECISION (char_type_node)); | |
2444 | len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars; | |
2445 | } | |
2446 | else if (TREE_CODE (ary) == VECTOR_CST) | |
f08ee65f | 2447 | /* We don't create variable-length VECTOR_CSTs. */ |
2448 | len = VECTOR_CST_NELTS (ary).to_constant (); | |
cf3cefc9 | 2449 | else |
2450 | { | |
2451 | /* We can't do anything with other tree codes, so use | |
2452 | VERIFY_CONSTANT to complain and fail. */ | |
2453 | VERIFY_CONSTANT (ary); | |
2454 | gcc_unreachable (); | |
2455 | } | |
aed8dc7f | 2456 | |
cf3cefc9 | 2457 | if (!tree_fits_shwi_p (index) |
2458 | || (i = tree_to_shwi (index)) < 0) | |
2459 | { | |
2460 | diag_array_subscript (ctx, ary, index); | |
2461 | *non_constant_p = true; | |
2462 | return t; | |
2463 | } | |
7963b19d | 2464 | } |
2465 | ||
51f0c7e2 | 2466 | tree nelts = get_array_or_vector_nelts (ctx, TREE_TYPE (ary), non_constant_p, |
2467 | overflow_p); | |
ce6a6978 | 2468 | VERIFY_CONSTANT (nelts); |
0acc6340 | 2469 | if ((lval |
2470 | ? !tree_int_cst_le (index, nelts) | |
2471 | : !tree_int_cst_lt (index, nelts)) | |
2472 | || tree_int_cst_sgn (index) < 0) | |
ce6a6978 | 2473 | { |
40df9099 | 2474 | diag_array_subscript (ctx, ary, index); |
ce6a6978 | 2475 | *non_constant_p = true; |
2476 | return t; | |
2477 | } | |
2478 | ||
cf3cefc9 | 2479 | if (lval && ary == oldary && index == oldidx) |
2480 | return t; | |
2481 | else if (lval) | |
2482 | return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL); | |
2483 | ||
7963b19d | 2484 | bool found; |
2485 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2486 | { | |
2487 | HOST_WIDE_INT ix = find_array_ctor_elt (ary, index); | |
2488 | found = (ix >= 0); | |
2489 | if (found) | |
2490 | i = ix; | |
aed8dc7f | 2491 | } |
7963b19d | 2492 | else |
2493 | found = (i < len); | |
aed8dc7f | 2494 | |
14869f28 | 2495 | if (found) |
2496 | { | |
2497 | tree r; | |
2498 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2499 | r = (*CONSTRUCTOR_ELTS (ary))[i].value; | |
2500 | else if (TREE_CODE (ary) == VECTOR_CST) | |
2501 | r = VECTOR_CST_ELT (ary, i); | |
14869f28 | 2502 | else |
92fe8840 | 2503 | r = extract_string_elt (ary, elem_nchars, i); |
2504 | ||
14869f28 | 2505 | if (r) |
2506 | /* Don't VERIFY_CONSTANT here. */ | |
2507 | return r; | |
09b42213 | 2508 | |
14869f28 | 2509 | /* Otherwise the element doesn't have a value yet. */ |
09b42213 | 2510 | } |
aed8dc7f | 2511 | |
14869f28 | 2512 | /* Not found. */ |
2513 | ||
2514 | if (TREE_CODE (ary) == CONSTRUCTOR | |
165d0d5b | 2515 | && CONSTRUCTOR_NO_CLEARING (ary)) |
09b42213 | 2516 | { |
14869f28 | 2517 | /* 'ary' is part of the aggregate initializer we're currently |
2518 | building; if there's no initializer for this element yet, | |
2519 | that's an error. */ | |
2520 | if (!ctx->quiet) | |
2521 | error ("accessing uninitialized array element"); | |
2522 | *non_constant_p = true; | |
2523 | return t; | |
09b42213 | 2524 | } |
14869f28 | 2525 | |
2526 | /* If it's within the array bounds but doesn't have an explicit | |
2527 | initializer, it's value-initialized. */ | |
2528 | tree val = build_value_init (elem_type, tf_warning_or_error); | |
2529 | return cxx_eval_constant_expression (ctx, val, lval, non_constant_p, | |
2530 | overflow_p); | |
09b42213 | 2531 | } |
2532 | ||
2533 | /* Subroutine of cxx_eval_constant_expression. | |
2534 | Attempt to reduce a field access of a value of class type. */ | |
2535 | ||
2536 | static tree | |
cf72f34d | 2537 | cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2538 | bool lval, |
09b42213 | 2539 | bool *non_constant_p, bool *overflow_p) |
2540 | { | |
2541 | unsigned HOST_WIDE_INT i; | |
2542 | tree field; | |
2543 | tree value; | |
2544 | tree part = TREE_OPERAND (t, 1); | |
2545 | tree orig_whole = TREE_OPERAND (t, 0); | |
cf72f34d | 2546 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2547 | lval, |
b2a43197 | 2548 | non_constant_p, overflow_p); |
7ab20d7c | 2549 | if (INDIRECT_REF_P (whole) |
2b1749c4 | 2550 | && integer_zerop (TREE_OPERAND (whole, 0))) |
2551 | { | |
2552 | if (!ctx->quiet) | |
2553 | error ("dereferencing a null pointer in %qE", orig_whole); | |
2554 | *non_constant_p = true; | |
2555 | return t; | |
2556 | } | |
cb768824 | 2557 | |
f16ed232 | 2558 | if (TREE_CODE (whole) == PTRMEM_CST) |
2559 | whole = cplus_expand_constant (whole); | |
09b42213 | 2560 | if (whole == orig_whole) |
2561 | return t; | |
1227ba74 | 2562 | if (lval) |
09b42213 | 2563 | return fold_build3 (COMPONENT_REF, TREE_TYPE (t), |
2564 | whole, part, NULL_TREE); | |
2565 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2566 | CONSTRUCTOR. */ | |
2567 | if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR) | |
2568 | { | |
f83e6885 | 2569 | if (!ctx->quiet) |
09b42213 | 2570 | error ("%qE is not a constant expression", orig_whole); |
2571 | *non_constant_p = true; | |
2572 | } | |
2573 | if (DECL_MUTABLE_P (part)) | |
2574 | { | |
f83e6885 | 2575 | if (!ctx->quiet) |
09b42213 | 2576 | error ("mutable %qD is not usable in a constant expression", part); |
2577 | *non_constant_p = true; | |
2578 | } | |
2579 | if (*non_constant_p) | |
2580 | return t; | |
a4360e57 | 2581 | bool pmf = TYPE_PTRMEMFUNC_P (TREE_TYPE (whole)); |
09b42213 | 2582 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) |
2583 | { | |
a4360e57 | 2584 | /* Use name match for PMF fields, as a variant will have a |
2585 | different FIELD_DECL with a different type. */ | |
2586 | if (pmf ? DECL_NAME (field) == DECL_NAME (part) | |
2587 | : field == part) | |
9c96033c | 2588 | { |
2589 | if (value) | |
2590 | return value; | |
2591 | else | |
2592 | /* We're in the middle of initializing it. */ | |
2593 | break; | |
2594 | } | |
09b42213 | 2595 | } |
2596 | if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE | |
2597 | && CONSTRUCTOR_NELTS (whole) > 0) | |
2598 | { | |
2599 | /* DR 1188 says we don't have to deal with this. */ | |
f83e6885 | 2600 | if (!ctx->quiet) |
09b42213 | 2601 | error ("accessing %qD member instead of initialized %qD member in " |
2602 | "constant expression", part, CONSTRUCTOR_ELT (whole, 0)->index); | |
2603 | *non_constant_p = true; | |
2604 | return t; | |
2605 | } | |
2606 | ||
f894a056 | 2607 | /* We only create a CONSTRUCTOR for a subobject when we modify it, so empty |
2608 | classes never get represented; throw together a value now. */ | |
2609 | if (is_really_empty_class (TREE_TYPE (t))) | |
2610 | return build_constructor (TREE_TYPE (t), NULL); | |
2611 | ||
a4360e57 | 2612 | gcc_assert (DECL_CONTEXT (part) == TYPE_MAIN_VARIANT (TREE_TYPE (whole))); |
2613 | ||
165d0d5b | 2614 | if (CONSTRUCTOR_NO_CLEARING (whole)) |
cf72f34d | 2615 | { |
2616 | /* 'whole' is part of the aggregate initializer we're currently | |
2617 | building; if there's no initializer for this member yet, that's an | |
f894a056 | 2618 | error. */ |
f83e6885 | 2619 | if (!ctx->quiet) |
cf72f34d | 2620 | error ("accessing uninitialized member %qD", part); |
2621 | *non_constant_p = true; | |
2622 | return t; | |
2623 | } | |
2624 | ||
09b42213 | 2625 | /* If there's no explicit init for this field, it's value-initialized. */ |
2626 | value = build_value_init (TREE_TYPE (t), tf_warning_or_error); | |
cf72f34d | 2627 | return cxx_eval_constant_expression (ctx, value, |
1227ba74 | 2628 | lval, |
b2a43197 | 2629 | non_constant_p, overflow_p); |
09b42213 | 2630 | } |
2631 | ||
2632 | /* Subroutine of cxx_eval_constant_expression. | |
2633 | Attempt to reduce a field access of a value of class type that is | |
2634 | expressed as a BIT_FIELD_REF. */ | |
2635 | ||
2636 | static tree | |
cf72f34d | 2637 | cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2638 | bool lval, |
09b42213 | 2639 | bool *non_constant_p, bool *overflow_p) |
2640 | { | |
2641 | tree orig_whole = TREE_OPERAND (t, 0); | |
2642 | tree retval, fldval, utype, mask; | |
2643 | bool fld_seen = false; | |
2644 | HOST_WIDE_INT istart, isize; | |
cf72f34d | 2645 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2646 | lval, |
b2a43197 | 2647 | non_constant_p, overflow_p); |
09b42213 | 2648 | tree start, field, value; |
2649 | unsigned HOST_WIDE_INT i; | |
2650 | ||
2651 | if (whole == orig_whole) | |
2652 | return t; | |
2653 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2654 | CONSTRUCTOR. */ | |
2655 | if (!*non_constant_p | |
2656 | && TREE_CODE (whole) != VECTOR_CST | |
2657 | && TREE_CODE (whole) != CONSTRUCTOR) | |
2658 | { | |
f83e6885 | 2659 | if (!ctx->quiet) |
09b42213 | 2660 | error ("%qE is not a constant expression", orig_whole); |
2661 | *non_constant_p = true; | |
2662 | } | |
2663 | if (*non_constant_p) | |
2664 | return t; | |
2665 | ||
2666 | if (TREE_CODE (whole) == VECTOR_CST) | |
2667 | return fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole, | |
2668 | TREE_OPERAND (t, 1), TREE_OPERAND (t, 2)); | |
2669 | ||
2670 | start = TREE_OPERAND (t, 2); | |
2671 | istart = tree_to_shwi (start); | |
2672 | isize = tree_to_shwi (TREE_OPERAND (t, 1)); | |
2673 | utype = TREE_TYPE (t); | |
2674 | if (!TYPE_UNSIGNED (utype)) | |
2675 | utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1); | |
2676 | retval = build_int_cst (utype, 0); | |
2677 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
2678 | { | |
2679 | tree bitpos = bit_position (field); | |
2680 | if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1)) | |
2681 | return value; | |
2682 | if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE | |
2683 | && TREE_CODE (value) == INTEGER_CST | |
2684 | && tree_fits_shwi_p (bitpos) | |
2685 | && tree_fits_shwi_p (DECL_SIZE (field))) | |
2686 | { | |
2687 | HOST_WIDE_INT bit = tree_to_shwi (bitpos); | |
2688 | HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field)); | |
2689 | HOST_WIDE_INT shift; | |
2690 | if (bit >= istart && bit + sz <= istart + isize) | |
2691 | { | |
2692 | fldval = fold_convert (utype, value); | |
2693 | mask = build_int_cst_type (utype, -1); | |
2694 | mask = fold_build2 (LSHIFT_EXPR, utype, mask, | |
2695 | size_int (TYPE_PRECISION (utype) - sz)); | |
2696 | mask = fold_build2 (RSHIFT_EXPR, utype, mask, | |
2697 | size_int (TYPE_PRECISION (utype) - sz)); | |
2698 | fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask); | |
2699 | shift = bit - istart; | |
2700 | if (BYTES_BIG_ENDIAN) | |
2701 | shift = TYPE_PRECISION (utype) - shift - sz; | |
2702 | fldval = fold_build2 (LSHIFT_EXPR, utype, fldval, | |
2703 | size_int (shift)); | |
2704 | retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval); | |
2705 | fld_seen = true; | |
2706 | } | |
2707 | } | |
2708 | } | |
2709 | if (fld_seen) | |
2710 | return fold_convert (TREE_TYPE (t), retval); | |
2711 | gcc_unreachable (); | |
2712 | return error_mark_node; | |
2713 | } | |
2714 | ||
2715 | /* Subroutine of cxx_eval_constant_expression. | |
2716 | Evaluate a short-circuited logical expression T in the context | |
2717 | of a given constexpr CALL. BAILOUT_VALUE is the value for | |
2718 | early return. CONTINUE_VALUE is used here purely for | |
2719 | sanity check purposes. */ | |
2720 | ||
2721 | static tree | |
cf72f34d | 2722 | cxx_eval_logical_expression (const constexpr_ctx *ctx, tree t, |
09b42213 | 2723 | tree bailout_value, tree continue_value, |
1227ba74 | 2724 | bool lval, |
09b42213 | 2725 | bool *non_constant_p, bool *overflow_p) |
2726 | { | |
2727 | tree r; | |
cf72f34d | 2728 | tree lhs = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 2729 | lval, |
b2a43197 | 2730 | non_constant_p, overflow_p); |
09b42213 | 2731 | VERIFY_CONSTANT (lhs); |
2732 | if (tree_int_cst_equal (lhs, bailout_value)) | |
2733 | return lhs; | |
2734 | gcc_assert (tree_int_cst_equal (lhs, continue_value)); | |
cf72f34d | 2735 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2736 | lval, non_constant_p, |
b2a43197 | 2737 | overflow_p); |
09b42213 | 2738 | VERIFY_CONSTANT (r); |
2739 | return r; | |
2740 | } | |
2741 | ||
2742 | /* REF is a COMPONENT_REF designating a particular field. V is a vector of | |
2743 | CONSTRUCTOR elements to initialize (part of) an object containing that | |
2744 | field. Return a pointer to the constructor_elt corresponding to the | |
2745 | initialization of the field. */ | |
2746 | ||
2747 | static constructor_elt * | |
2748 | base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref) | |
2749 | { | |
2750 | tree aggr = TREE_OPERAND (ref, 0); | |
2751 | tree field = TREE_OPERAND (ref, 1); | |
2752 | HOST_WIDE_INT i; | |
2753 | constructor_elt *ce; | |
2754 | ||
2755 | gcc_assert (TREE_CODE (ref) == COMPONENT_REF); | |
2756 | ||
2757 | if (TREE_CODE (aggr) == COMPONENT_REF) | |
2758 | { | |
2759 | constructor_elt *base_ce | |
2760 | = base_field_constructor_elt (v, aggr); | |
2761 | v = CONSTRUCTOR_ELTS (base_ce->value); | |
2762 | } | |
2763 | ||
2764 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2765 | if (ce->index == field) | |
2766 | return ce; | |
2767 | ||
2768 | gcc_unreachable (); | |
2769 | return NULL; | |
2770 | } | |
2771 | ||
cf72f34d | 2772 | /* Some of the expressions fed to the constexpr mechanism are calls to |
2773 | constructors, which have type void. In that case, return the type being | |
2774 | initialized by the constructor. */ | |
2775 | ||
2776 | static tree | |
2777 | initialized_type (tree t) | |
2778 | { | |
2779 | if (TYPE_P (t)) | |
2780 | return t; | |
2781 | tree type = cv_unqualified (TREE_TYPE (t)); | |
2782 | if (TREE_CODE (t) == CALL_EXPR || TREE_CODE (t) == AGGR_INIT_EXPR) | |
2783 | { | |
2784 | /* A constructor call has void type, so we need to look deeper. */ | |
2785 | tree fn = get_function_named_in_call (t); | |
2786 | if (fn && TREE_CODE (fn) == FUNCTION_DECL | |
2787 | && DECL_CXX_CONSTRUCTOR_P (fn)) | |
2788 | type = DECL_CONTEXT (fn); | |
2789 | } | |
2790 | return type; | |
2791 | } | |
2792 | ||
2793 | /* We're about to initialize element INDEX of an array or class from VALUE. | |
2794 | Set up NEW_CTX appropriately by adjusting .object to refer to the | |
2795 | subobject and creating a new CONSTRUCTOR if the element is itself | |
2796 | a class or array. */ | |
2797 | ||
2798 | static void | |
2799 | init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, | |
2800 | tree index, tree &value) | |
2801 | { | |
2802 | new_ctx = *ctx; | |
2803 | ||
2804 | if (index && TREE_CODE (index) != INTEGER_CST | |
2805 | && TREE_CODE (index) != FIELD_DECL) | |
2806 | /* This won't have an element in the new CONSTRUCTOR. */ | |
2807 | return; | |
2808 | ||
2809 | tree type = initialized_type (value); | |
2810 | if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) | |
2811 | /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ | |
2812 | return; | |
2813 | ||
2814 | /* The sub-aggregate initializer might contain a placeholder; | |
2815 | update object to refer to the subobject and ctor to refer to | |
2816 | the (newly created) sub-initializer. */ | |
2817 | if (ctx->object) | |
2818 | new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); | |
2819 | tree elt = build_constructor (type, NULL); | |
165d0d5b | 2820 | CONSTRUCTOR_NO_CLEARING (elt) = true; |
cf72f34d | 2821 | new_ctx.ctor = elt; |
2822 | ||
2823 | if (TREE_CODE (value) == TARGET_EXPR) | |
2824 | /* Avoid creating another CONSTRUCTOR when we expand the TARGET_EXPR. */ | |
2825 | value = TARGET_EXPR_INITIAL (value); | |
2826 | } | |
2827 | ||
2828 | /* We're about to process an initializer for a class or array TYPE. Make | |
2829 | sure that CTX is set up appropriately. */ | |
2830 | ||
2831 | static void | |
2832 | verify_ctor_sanity (const constexpr_ctx *ctx, tree type) | |
2833 | { | |
2834 | /* We don't bother building a ctor for an empty base subobject. */ | |
2835 | if (is_empty_class (type)) | |
2836 | return; | |
2837 | ||
2838 | /* We're in the middle of an initializer that might involve placeholders; | |
2839 | our caller should have created a CONSTRUCTOR for us to put the | |
2840 | initializer into. We will either return that constructor or T. */ | |
2841 | gcc_assert (ctx->ctor); | |
2842 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2843 | (type, TREE_TYPE (ctx->ctor))); | |
bbf58224 | 2844 | /* We used to check that ctx->ctor was empty, but that isn't the case when |
2845 | the object is zero-initialized before calling the constructor. */ | |
cf72f34d | 2846 | if (ctx->object) |
d9751a3c | 2847 | { |
2848 | tree otype = TREE_TYPE (ctx->object); | |
2849 | gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, otype) | |
2850 | /* Handle flexible array members. */ | |
2851 | || (TREE_CODE (otype) == ARRAY_TYPE | |
2852 | && TYPE_DOMAIN (otype) == NULL_TREE | |
2853 | && TREE_CODE (type) == ARRAY_TYPE | |
2854 | && (same_type_ignoring_top_level_qualifiers_p | |
2855 | (TREE_TYPE (type), TREE_TYPE (otype))))); | |
2856 | } | |
cf72f34d | 2857 | gcc_assert (!ctx->object || !DECL_P (ctx->object) |
2858 | || *(ctx->values->get (ctx->object)) == ctx->ctor); | |
2859 | } | |
2860 | ||
09b42213 | 2861 | /* Subroutine of cxx_eval_constant_expression. |
2862 | The expression tree T denotes a C-style array or a C-style | |
2863 | aggregate. Reduce it to a constant expression. */ | |
2864 | ||
2865 | static tree | |
cf72f34d | 2866 | cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2867 | bool lval, |
09b42213 | 2868 | bool *non_constant_p, bool *overflow_p) |
2869 | { | |
2870 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
09b42213 | 2871 | bool changed = false; |
2872 | gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t)); | |
68464393 | 2873 | tree type = TREE_TYPE (t); |
cf72f34d | 2874 | |
68464393 | 2875 | constexpr_ctx new_ctx; |
d2dd85e3 | 2876 | if (TYPE_PTRMEMFUNC_P (type) || VECTOR_TYPE_P (type)) |
68464393 | 2877 | { |
d2dd85e3 | 2878 | /* We don't really need the ctx->ctor business for a PMF or |
2879 | vector, but it's simpler to use the same code. */ | |
68464393 | 2880 | new_ctx = *ctx; |
2881 | new_ctx.ctor = build_constructor (type, NULL); | |
2882 | new_ctx.object = NULL_TREE; | |
2883 | ctx = &new_ctx; | |
2884 | }; | |
2885 | verify_ctor_sanity (ctx, type); | |
cf72f34d | 2886 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); |
2887 | vec_alloc (*p, vec_safe_length (v)); | |
2888 | ||
58b0f9ce | 2889 | unsigned i; |
2890 | tree index, value; | |
2891 | bool constant_p = true; | |
2892 | bool side_effects_p = false; | |
cf72f34d | 2893 | FOR_EACH_CONSTRUCTOR_ELT (v, i, index, value) |
09b42213 | 2894 | { |
5ae773e4 | 2895 | tree orig_value = value; |
cf72f34d | 2896 | init_subob_ctx (ctx, new_ctx, index, value); |
2897 | if (new_ctx.ctor != ctx->ctor) | |
2898 | /* If we built a new CONSTRUCTOR, attach it now so that other | |
2899 | initializers can refer to it. */ | |
2900 | CONSTRUCTOR_APPEND_ELT (*p, index, new_ctx.ctor); | |
2901 | tree elt = cxx_eval_constant_expression (&new_ctx, value, | |
1227ba74 | 2902 | lval, |
b2a43197 | 2903 | non_constant_p, overflow_p); |
09b42213 | 2904 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 2905 | if (ctx->quiet && *non_constant_p) |
cf72f34d | 2906 | break; |
5ae773e4 | 2907 | if (elt != orig_value) |
09b42213 | 2908 | changed = true; |
58b0f9ce | 2909 | |
2910 | if (!TREE_CONSTANT (elt)) | |
2911 | constant_p = false; | |
2912 | if (TREE_SIDE_EFFECTS (elt)) | |
2913 | side_effects_p = true; | |
cf72f34d | 2914 | if (index && TREE_CODE (index) == COMPONENT_REF) |
09b42213 | 2915 | { |
2916 | /* This is an initialization of a vfield inside a base | |
2917 | subaggregate that we already initialized; push this | |
2918 | initialization into the previous initialization. */ | |
cf72f34d | 2919 | constructor_elt *inner = base_field_constructor_elt (*p, index); |
09b42213 | 2920 | inner->value = elt; |
cf72f34d | 2921 | changed = true; |
09b42213 | 2922 | } |
cf72f34d | 2923 | else if (index |
2924 | && (TREE_CODE (index) == NOP_EXPR | |
2925 | || TREE_CODE (index) == POINTER_PLUS_EXPR)) | |
09b42213 | 2926 | { |
2927 | /* This is an initializer for an empty base; now that we've | |
2928 | checked that it's constant, we can ignore it. */ | |
cf72f34d | 2929 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (index)))); |
2930 | changed = true; | |
2931 | } | |
09b42213 | 2932 | else |
79e65a6b | 2933 | { |
0dd49b5a | 2934 | if (new_ctx.ctor != ctx->ctor) |
2935 | { | |
2936 | /* We appended this element above; update the value. */ | |
2937 | gcc_assert ((*p)->last().index == index); | |
2938 | (*p)->last().value = elt; | |
2939 | } | |
2940 | else | |
2941 | CONSTRUCTOR_APPEND_ELT (*p, index, elt); | |
2942 | /* Adding or replacing an element might change the ctor's flags. */ | |
79e65a6b | 2943 | TREE_CONSTANT (ctx->ctor) = constant_p; |
2944 | TREE_SIDE_EFFECTS (ctx->ctor) = side_effects_p; | |
2945 | } | |
09b42213 | 2946 | } |
2947 | if (*non_constant_p || !changed) | |
cf72f34d | 2948 | return t; |
2949 | t = ctx->ctor; | |
2950 | /* We're done building this CONSTRUCTOR, so now we can interpret an | |
2951 | element without an explicit initializer as value-initialized. */ | |
165d0d5b | 2952 | CONSTRUCTOR_NO_CLEARING (t) = false; |
58b0f9ce | 2953 | TREE_CONSTANT (t) = constant_p; |
2954 | TREE_SIDE_EFFECTS (t) = side_effects_p; | |
68464393 | 2955 | if (VECTOR_TYPE_P (type)) |
09b42213 | 2956 | t = fold (t); |
2957 | return t; | |
2958 | } | |
2959 | ||
2960 | /* Subroutine of cxx_eval_constant_expression. | |
2961 | The expression tree T is a VEC_INIT_EXPR which denotes the desired | |
2962 | initialization of a non-static data member of array type. Reduce it to a | |
2963 | CONSTRUCTOR. | |
2964 | ||
2965 | Note that apart from value-initialization (when VALUE_INIT is true), | |
2966 | this is only intended to support value-initialization and the | |
2967 | initializations done by defaulted constructors for classes with | |
2968 | non-static data members of array type. In this case, VEC_INIT_EXPR_INIT | |
2969 | will either be NULL_TREE for the default constructor, or a COMPONENT_REF | |
2970 | for the copy/move constructor. */ | |
2971 | ||
2972 | static tree | |
cf72f34d | 2973 | cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, |
1227ba74 | 2974 | bool value_init, bool lval, |
09b42213 | 2975 | bool *non_constant_p, bool *overflow_p) |
2976 | { | |
2977 | tree elttype = TREE_TYPE (atype); | |
cf72f34d | 2978 | verify_ctor_sanity (ctx, atype); |
2979 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
09b42213 | 2980 | bool pre_init = false; |
3e520b97 | 2981 | unsigned HOST_WIDE_INT i; |
c4970310 | 2982 | tsubst_flags_t complain = ctx->quiet ? tf_none : tf_warning_or_error; |
09b42213 | 2983 | |
2984 | /* For the default constructor, build up a call to the default | |
2985 | constructor of the element type. We only need to handle class types | |
2986 | here, as for a constructor to be constexpr, all members must be | |
2987 | initialized, which for a defaulted default constructor means they must | |
2988 | be of a class type with a constexpr default constructor. */ | |
2989 | if (TREE_CODE (elttype) == ARRAY_TYPE) | |
2990 | /* We only do this at the lowest level. */; | |
2991 | else if (value_init) | |
2992 | { | |
c4970310 | 2993 | init = build_value_init (elttype, complain); |
09b42213 | 2994 | pre_init = true; |
2995 | } | |
2996 | else if (!init) | |
2997 | { | |
2998 | vec<tree, va_gc> *argvec = make_tree_vector (); | |
2999 | init = build_special_member_call (NULL_TREE, complete_ctor_identifier, | |
3000 | &argvec, elttype, LOOKUP_NORMAL, | |
c4970310 | 3001 | complain); |
09b42213 | 3002 | release_tree_vector (argvec); |
9c96033c | 3003 | init = build_aggr_init_expr (TREE_TYPE (init), init); |
09b42213 | 3004 | pre_init = true; |
3005 | } | |
3006 | ||
51f0c7e2 | 3007 | tree nelts = get_array_or_vector_nelts (ctx, atype, non_constant_p, |
3008 | overflow_p); | |
3009 | unsigned HOST_WIDE_INT max = tree_to_uhwi (nelts); | |
3e520b97 | 3010 | for (i = 0; i < max; ++i) |
09b42213 | 3011 | { |
3012 | tree idx = build_int_cst (size_type_node, i); | |
3013 | tree eltinit; | |
d9377ad5 | 3014 | bool reuse = false; |
cf72f34d | 3015 | constexpr_ctx new_ctx; |
3016 | init_subob_ctx (ctx, new_ctx, idx, pre_init ? init : elttype); | |
3017 | if (new_ctx.ctor != ctx->ctor) | |
3018 | CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor); | |
09b42213 | 3019 | if (TREE_CODE (elttype) == ARRAY_TYPE) |
3020 | { | |
3021 | /* A multidimensional array; recurse. */ | |
3022 | if (value_init || init == NULL_TREE) | |
d9377ad5 | 3023 | { |
3024 | eltinit = NULL_TREE; | |
3025 | reuse = i == 0; | |
3026 | } | |
09b42213 | 3027 | else |
c4970310 | 3028 | eltinit = cp_build_array_ref (input_location, init, idx, complain); |
cf72f34d | 3029 | eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, value_init, |
1227ba74 | 3030 | lval, |
09b42213 | 3031 | non_constant_p, overflow_p); |
3032 | } | |
3033 | else if (pre_init) | |
3034 | { | |
3035 | /* Initializing an element using value or default initialization | |
3036 | we just pre-built above. */ | |
d9377ad5 | 3037 | eltinit = cxx_eval_constant_expression (&new_ctx, init, lval, |
3038 | non_constant_p, overflow_p); | |
3039 | reuse = i == 0; | |
09b42213 | 3040 | } |
3041 | else | |
3042 | { | |
3043 | /* Copying an element. */ | |
3044 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
3045 | (atype, TREE_TYPE (init))); | |
c4970310 | 3046 | eltinit = cp_build_array_ref (input_location, init, idx, complain); |
18bede74 | 3047 | if (!lvalue_p (init)) |
09b42213 | 3048 | eltinit = move (eltinit); |
c4970310 | 3049 | eltinit = force_rvalue (eltinit, complain); |
eb7c25cc | 3050 | eltinit = cxx_eval_constant_expression (&new_ctx, eltinit, lval, |
3051 | non_constant_p, overflow_p); | |
09b42213 | 3052 | } |
f83e6885 | 3053 | if (*non_constant_p && !ctx->quiet) |
cf72f34d | 3054 | break; |
3055 | if (new_ctx.ctor != ctx->ctor) | |
3056 | { | |
3057 | /* We appended this element above; update the value. */ | |
3058 | gcc_assert ((*p)->last().index == idx); | |
3059 | (*p)->last().value = eltinit; | |
3060 | } | |
3061 | else | |
3062 | CONSTRUCTOR_APPEND_ELT (*p, idx, eltinit); | |
d9377ad5 | 3063 | /* Reuse the result of cxx_eval_constant_expression call |
eb7c25cc | 3064 | from the first iteration to all others if it is a constant |
3065 | initializer that doesn't require relocations. */ | |
d9377ad5 | 3066 | if (reuse |
3067 | && max > 1 | |
eb7c25cc | 3068 | && (eltinit == NULL_TREE |
3069 | || (initializer_constant_valid_p (eltinit, TREE_TYPE (eltinit)) | |
3070 | == null_pointer_node))) | |
d9377ad5 | 3071 | { |
3072 | if (new_ctx.ctor != ctx->ctor) | |
3073 | eltinit = new_ctx.ctor; | |
228a2cd8 | 3074 | tree range = build2 (RANGE_EXPR, size_type_node, |
3075 | build_int_cst (size_type_node, 1), | |
3076 | build_int_cst (size_type_node, max - 1)); | |
3077 | CONSTRUCTOR_APPEND_ELT (*p, range, unshare_constructor (eltinit)); | |
d9377ad5 | 3078 | break; |
3079 | } | |
228a2cd8 | 3080 | else if (i == 0) |
3081 | vec_safe_reserve (*p, max); | |
09b42213 | 3082 | } |
3083 | ||
3084 | if (!*non_constant_p) | |
3085 | { | |
cf72f34d | 3086 | init = ctx->ctor; |
165d0d5b | 3087 | CONSTRUCTOR_NO_CLEARING (init) = false; |
09b42213 | 3088 | } |
09b42213 | 3089 | return init; |
3090 | } | |
3091 | ||
3092 | static tree | |
cf72f34d | 3093 | cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3094 | bool lval, |
09b42213 | 3095 | bool *non_constant_p, bool *overflow_p) |
3096 | { | |
3097 | tree atype = TREE_TYPE (t); | |
3098 | tree init = VEC_INIT_EXPR_INIT (t); | |
cf72f34d | 3099 | tree r = cxx_eval_vec_init_1 (ctx, atype, init, |
09b42213 | 3100 | VEC_INIT_EXPR_VALUE_INIT (t), |
1227ba74 | 3101 | lval, non_constant_p, overflow_p); |
09b42213 | 3102 | if (*non_constant_p) |
3103 | return t; | |
3104 | else | |
3105 | return r; | |
3106 | } | |
3107 | ||
6b53d686 | 3108 | /* Like same_type_ignoring_top_level_qualifiers_p, but also handle the case |
3109 | where the desired type is an array of unknown bounds because the variable | |
3110 | has had its bounds deduced since the wrapping expression was created. */ | |
3111 | ||
3112 | static bool | |
3113 | same_type_ignoring_tlq_and_bounds_p (tree type1, tree type2) | |
3114 | { | |
3115 | while (TREE_CODE (type1) == ARRAY_TYPE | |
3116 | && TREE_CODE (type2) == ARRAY_TYPE | |
3117 | && (!TYPE_DOMAIN (type1) || !TYPE_DOMAIN (type2))) | |
3118 | { | |
3119 | type1 = TREE_TYPE (type1); | |
3120 | type2 = TREE_TYPE (type2); | |
3121 | } | |
3122 | return same_type_ignoring_top_level_qualifiers_p (type1, type2); | |
3123 | } | |
3124 | ||
09b42213 | 3125 | /* A less strict version of fold_indirect_ref_1, which requires cv-quals to |
3126 | match. We want to be less strict for simple *& folding; if we have a | |
3127 | non-const temporary that we access through a const pointer, that should | |
3128 | work. We handle this here rather than change fold_indirect_ref_1 | |
3129 | because we're dealing with things like ADDR_EXPR of INTEGER_CST which | |
3130 | don't really make sense outside of constant expression evaluation. Also | |
3131 | we want to allow folding to COMPONENT_REF, which could cause trouble | |
3132 | with TBAA in fold_indirect_ref_1. | |
3133 | ||
3134 | Try to keep this function synced with fold_indirect_ref_1. */ | |
3135 | ||
3136 | static tree | |
3137 | cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) | |
3138 | { | |
7d8e655d | 3139 | tree sub = op0; |
3140 | tree subtype; | |
3141 | poly_uint64 const_op01; | |
09b42213 | 3142 | |
09b42213 | 3143 | STRIP_NOPS (sub); |
3144 | subtype = TREE_TYPE (sub); | |
d03fa520 | 3145 | if (!INDIRECT_TYPE_P (subtype)) |
09b42213 | 3146 | return NULL_TREE; |
3147 | ||
3148 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3149 | { | |
3150 | tree op = TREE_OPERAND (sub, 0); | |
3151 | tree optype = TREE_TYPE (op); | |
3152 | ||
3153 | /* *&CONST_DECL -> to the value of the const decl. */ | |
3154 | if (TREE_CODE (op) == CONST_DECL) | |
3155 | return DECL_INITIAL (op); | |
3156 | /* *&p => p; make sure to handle *&"str"[cst] here. */ | |
6b53d686 | 3157 | if (same_type_ignoring_tlq_and_bounds_p (optype, type)) |
09b42213 | 3158 | { |
3159 | tree fop = fold_read_from_constant_string (op); | |
3160 | if (fop) | |
3161 | return fop; | |
3162 | else | |
3163 | return op; | |
3164 | } | |
3165 | /* *(foo *)&fooarray => fooarray[0] */ | |
3166 | else if (TREE_CODE (optype) == ARRAY_TYPE | |
3167 | && (same_type_ignoring_top_level_qualifiers_p | |
3168 | (type, TREE_TYPE (optype)))) | |
3169 | { | |
3170 | tree type_domain = TYPE_DOMAIN (optype); | |
3171 | tree min_val = size_zero_node; | |
3172 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3173 | min_val = TYPE_MIN_VALUE (type_domain); | |
3174 | return build4_loc (loc, ARRAY_REF, type, op, min_val, | |
3175 | NULL_TREE, NULL_TREE); | |
3176 | } | |
3177 | /* *(foo *)&complexfoo => __real__ complexfoo */ | |
3178 | else if (TREE_CODE (optype) == COMPLEX_TYPE | |
3179 | && (same_type_ignoring_top_level_qualifiers_p | |
3180 | (type, TREE_TYPE (optype)))) | |
3181 | return fold_build1_loc (loc, REALPART_EXPR, type, op); | |
3182 | /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3183 | else if (VECTOR_TYPE_P (optype) |
09b42213 | 3184 | && (same_type_ignoring_top_level_qualifiers_p |
3185 | (type, TREE_TYPE (optype)))) | |
3186 | { | |
3187 | tree part_width = TYPE_SIZE (type); | |
3188 | tree index = bitsize_int (0); | |
7d8e655d | 3189 | return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, |
3190 | index); | |
09b42213 | 3191 | } |
3192 | /* Also handle conversion to an empty base class, which | |
3193 | is represented with a NOP_EXPR. */ | |
3194 | else if (is_empty_class (type) | |
3195 | && CLASS_TYPE_P (optype) | |
3196 | && DERIVED_FROM_P (type, optype)) | |
3197 | { | |
3198 | *empty_base = true; | |
3199 | return op; | |
3200 | } | |
3201 | /* *(foo *)&struct_with_foo_field => COMPONENT_REF */ | |
3202 | else if (RECORD_OR_UNION_TYPE_P (optype)) | |
3203 | { | |
3204 | tree field = TYPE_FIELDS (optype); | |
3205 | for (; field; field = DECL_CHAIN (field)) | |
3206 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3207 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3208 | && integer_zerop (byte_position (field)) |
3209 | && (same_type_ignoring_top_level_qualifiers_p | |
3210 | (TREE_TYPE (field), type))) | |
a48667ee | 3211 | return fold_build3 (COMPONENT_REF, type, op, field, NULL_TREE); |
09b42213 | 3212 | } |
3213 | } | |
3214 | else if (TREE_CODE (sub) == POINTER_PLUS_EXPR | |
7d8e655d | 3215 | && poly_int_tree_p (TREE_OPERAND (sub, 1), &const_op01)) |
09b42213 | 3216 | { |
3217 | tree op00 = TREE_OPERAND (sub, 0); | |
3218 | tree op01 = TREE_OPERAND (sub, 1); | |
3219 | ||
3220 | STRIP_NOPS (op00); | |
3221 | if (TREE_CODE (op00) == ADDR_EXPR) | |
3222 | { | |
3223 | tree op00type; | |
3224 | op00 = TREE_OPERAND (op00, 0); | |
3225 | op00type = TREE_TYPE (op00); | |
3226 | ||
3227 | /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3228 | if (VECTOR_TYPE_P (op00type) |
7d8e655d | 3229 | && same_type_ignoring_top_level_qualifiers_p |
3230 | (type, TREE_TYPE (op00type)) | |
3231 | /* POINTER_PLUS_EXPR second operand is sizetype, unsigned, | |
3232 | but we want to treat offsets with MSB set as negative. | |
3233 | For the code below negative offsets are invalid and | |
3234 | TYPE_SIZE of the element is something unsigned, so | |
3235 | check whether op01 fits into poly_int64, which implies | |
3236 | it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and | |
3237 | then just use poly_uint64 because we want to treat the | |
3238 | value as unsigned. */ | |
3239 | && tree_fits_poly_int64_p (op01)) | |
09b42213 | 3240 | { |
09b42213 | 3241 | tree part_width = TYPE_SIZE (type); |
7d8e655d | 3242 | poly_uint64 max_offset |
3243 | = (tree_to_uhwi (part_width) / BITS_PER_UNIT | |
3244 | * TYPE_VECTOR_SUBPARTS (op00type)); | |
3245 | if (known_lt (const_op01, max_offset)) | |
3246 | { | |
3247 | tree index = bitsize_int (const_op01 * BITS_PER_UNIT); | |
3248 | return fold_build3_loc (loc, | |
3249 | BIT_FIELD_REF, type, op00, | |
3250 | part_width, index); | |
3251 | } | |
09b42213 | 3252 | } |
3253 | /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ | |
3254 | else if (TREE_CODE (op00type) == COMPLEX_TYPE | |
3255 | && (same_type_ignoring_top_level_qualifiers_p | |
3256 | (type, TREE_TYPE (op00type)))) | |
3257 | { | |
7d8e655d | 3258 | if (known_eq (wi::to_poly_offset (TYPE_SIZE_UNIT (type)), |
3259 | const_op01)) | |
09b42213 | 3260 | return fold_build1_loc (loc, IMAGPART_EXPR, type, op00); |
3261 | } | |
3262 | /* ((foo *)&fooarray)[1] => fooarray[1] */ | |
3263 | else if (TREE_CODE (op00type) == ARRAY_TYPE | |
3264 | && (same_type_ignoring_top_level_qualifiers_p | |
3265 | (type, TREE_TYPE (op00type)))) | |
3266 | { | |
3267 | tree type_domain = TYPE_DOMAIN (op00type); | |
3268 | tree min_val = size_zero_node; | |
3269 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3270 | min_val = TYPE_MIN_VALUE (type_domain); | |
53fa96c0 | 3271 | offset_int off = wi::to_offset (op01); |
3272 | offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type)); | |
3273 | offset_int remainder; | |
3274 | off = wi::divmod_trunc (off, el_sz, SIGNED, &remainder); | |
3275 | if (remainder == 0 && TREE_CODE (min_val) == INTEGER_CST) | |
3276 | { | |
3277 | off = off + wi::to_offset (min_val); | |
3278 | op01 = wide_int_to_tree (sizetype, off); | |
3279 | return build4_loc (loc, ARRAY_REF, type, op00, op01, | |
3280 | NULL_TREE, NULL_TREE); | |
3281 | } | |
09b42213 | 3282 | } |
3283 | /* Also handle conversion to an empty base class, which | |
3284 | is represented with a NOP_EXPR. */ | |
3285 | else if (is_empty_class (type) | |
3286 | && CLASS_TYPE_P (op00type) | |
3287 | && DERIVED_FROM_P (type, op00type)) | |
3288 | { | |
3289 | *empty_base = true; | |
3290 | return op00; | |
3291 | } | |
3292 | /* ((foo *)&struct_with_foo_field)[1] => COMPONENT_REF */ | |
3293 | else if (RECORD_OR_UNION_TYPE_P (op00type)) | |
3294 | { | |
3295 | tree field = TYPE_FIELDS (op00type); | |
3296 | for (; field; field = DECL_CHAIN (field)) | |
3297 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3298 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3299 | && tree_int_cst_equal (byte_position (field), op01) |
3300 | && (same_type_ignoring_top_level_qualifiers_p | |
3301 | (TREE_TYPE (field), type))) | |
a48667ee | 3302 | return fold_build3 (COMPONENT_REF, type, op00, |
3303 | field, NULL_TREE); | |
09b42213 | 3304 | } |
3305 | } | |
3306 | } | |
3307 | /* *(foo *)fooarrptr => (*fooarrptr)[0] */ | |
3308 | else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE | |
3309 | && (same_type_ignoring_top_level_qualifiers_p | |
3310 | (type, TREE_TYPE (TREE_TYPE (subtype))))) | |
3311 | { | |
3312 | tree type_domain; | |
3313 | tree min_val = size_zero_node; | |
7d8e655d | 3314 | tree newsub |
3315 | = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL); | |
09b42213 | 3316 | if (newsub) |
3317 | sub = newsub; | |
3318 | else | |
3319 | sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub); | |
3320 | type_domain = TYPE_DOMAIN (TREE_TYPE (sub)); | |
3321 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3322 | min_val = TYPE_MIN_VALUE (type_domain); | |
3323 | return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE, | |
3324 | NULL_TREE); | |
3325 | } | |
3326 | ||
3327 | return NULL_TREE; | |
3328 | } | |
3329 | ||
3330 | static tree | |
cf72f34d | 3331 | cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3332 | bool lval, |
09b42213 | 3333 | bool *non_constant_p, bool *overflow_p) |
3334 | { | |
3335 | tree orig_op0 = TREE_OPERAND (t, 0); | |
09b42213 | 3336 | bool empty_base = false; |
09b42213 | 3337 | |
d2c63826 | 3338 | /* We can handle a MEM_REF like an INDIRECT_REF, if MEM_REF's second |
3339 | operand is an integer-zero. Otherwise reject the MEM_REF for now. */ | |
3340 | ||
3341 | if (TREE_CODE (t) == MEM_REF | |
3342 | && (!TREE_OPERAND (t, 1) || !integer_zerop (TREE_OPERAND (t, 1)))) | |
3343 | { | |
3344 | gcc_assert (ctx->quiet); | |
3345 | *non_constant_p = true; | |
3346 | return t; | |
3347 | } | |
3348 | ||
7e0f3388 | 3349 | /* First try to simplify it directly. */ |
3350 | tree r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), orig_op0, | |
3351 | &empty_base); | |
3352 | if (!r) | |
09b42213 | 3353 | { |
7e0f3388 | 3354 | /* If that didn't work, evaluate the operand first. */ |
3355 | tree op0 = cxx_eval_constant_expression (ctx, orig_op0, | |
3356 | /*lval*/false, non_constant_p, | |
3357 | overflow_p); | |
3358 | /* Don't VERIFY_CONSTANT here. */ | |
3359 | if (*non_constant_p) | |
3360 | return t; | |
3361 | ||
cb768824 | 3362 | if (!lval && integer_zerop (op0)) |
3363 | { | |
3364 | if (!ctx->quiet) | |
3365 | error ("dereferencing a null pointer"); | |
3366 | *non_constant_p = true; | |
3367 | return t; | |
3368 | } | |
3369 | ||
7e0f3388 | 3370 | r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), op0, |
3371 | &empty_base); | |
3372 | if (r == NULL_TREE) | |
09b42213 | 3373 | { |
3374 | /* We couldn't fold to a constant value. Make sure it's not | |
3375 | something we should have been able to fold. */ | |
7e0f3388 | 3376 | tree sub = op0; |
3377 | STRIP_NOPS (sub); | |
3378 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3379 | { | |
3380 | gcc_assert (!same_type_ignoring_top_level_qualifiers_p | |
3381 | (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t))); | |
3382 | /* DR 1188 says we don't have to deal with this. */ | |
3383 | if (!ctx->quiet) | |
3384 | error ("accessing value of %qE through a %qT glvalue in a " | |
3385 | "constant expression", build_fold_indirect_ref (sub), | |
3386 | TREE_TYPE (t)); | |
3387 | *non_constant_p = true; | |
3388 | return t; | |
3389 | } | |
3390 | ||
3391 | if (lval && op0 != orig_op0) | |
3392 | return build1 (INDIRECT_REF, TREE_TYPE (t), op0); | |
3393 | if (!lval) | |
3394 | VERIFY_CONSTANT (t); | |
09b42213 | 3395 | return t; |
3396 | } | |
3397 | } | |
3398 | ||
7e0f3388 | 3399 | r = cxx_eval_constant_expression (ctx, r, |
3400 | lval, non_constant_p, overflow_p); | |
3401 | if (*non_constant_p) | |
3402 | return t; | |
3403 | ||
ce4ffd9e | 3404 | /* If we're pulling out the value of an empty base, just return an empty |
09b42213 | 3405 | CONSTRUCTOR. */ |
1227ba74 | 3406 | if (empty_base && !lval) |
09b42213 | 3407 | { |
09b42213 | 3408 | r = build_constructor (TREE_TYPE (t), NULL); |
3409 | TREE_CONSTANT (r) = true; | |
3410 | } | |
3411 | ||
09b42213 | 3412 | return r; |
3413 | } | |
3414 | ||
3415 | /* Complain about R, a VAR_DECL, not being usable in a constant expression. | |
3416 | Shared between potential_constant_expression and | |
3417 | cxx_eval_constant_expression. */ | |
3418 | ||
3419 | static void | |
3420 | non_const_var_error (tree r) | |
3421 | { | |
3422 | tree type = TREE_TYPE (r); | |
3423 | error ("the value of %qD is not usable in a constant " | |
3424 | "expression", r); | |
3425 | /* Avoid error cascade. */ | |
3426 | if (DECL_INITIAL (r) == error_mark_node) | |
3427 | return; | |
3428 | if (DECL_DECLARED_CONSTEXPR_P (r)) | |
3429 | inform (DECL_SOURCE_LOCATION (r), | |
3430 | "%qD used in its own initializer", r); | |
3431 | else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) | |
3432 | { | |
3433 | if (!CP_TYPE_CONST_P (type)) | |
3434 | inform (DECL_SOURCE_LOCATION (r), | |
3435 | "%q#D is not const", r); | |
3436 | else if (CP_TYPE_VOLATILE_P (type)) | |
3437 | inform (DECL_SOURCE_LOCATION (r), | |
3438 | "%q#D is volatile", r); | |
3439 | else if (!DECL_INITIAL (r) | |
c8e3e744 | 3440 | || !TREE_CONSTANT (DECL_INITIAL (r)) |
3441 | || !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (r)) | |
09b42213 | 3442 | inform (DECL_SOURCE_LOCATION (r), |
3443 | "%qD was not initialized with a constant " | |
3444 | "expression", r); | |
3445 | else | |
3446 | gcc_unreachable (); | |
3447 | } | |
90ad495b | 3448 | else if (TYPE_REF_P (type)) |
ac6641ca | 3449 | inform (DECL_SOURCE_LOCATION (r), |
3450 | "%qD was not initialized with a constant " | |
3451 | "expression", r); | |
09b42213 | 3452 | else |
3453 | { | |
3454 | if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r)) | |
3455 | inform (DECL_SOURCE_LOCATION (r), | |
3456 | "%qD was not declared %<constexpr%>", r); | |
3457 | else | |
3458 | inform (DECL_SOURCE_LOCATION (r), | |
3459 | "%qD does not have integral or enumeration type", | |
3460 | r); | |
3461 | } | |
3462 | } | |
3463 | ||
3464 | /* Subroutine of cxx_eval_constant_expression. | |
3465 | Like cxx_eval_unary_expression, except for trinary expressions. */ | |
3466 | ||
3467 | static tree | |
cf72f34d | 3468 | cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3469 | bool lval, |
09b42213 | 3470 | bool *non_constant_p, bool *overflow_p) |
3471 | { | |
3472 | int i; | |
3473 | tree args[3]; | |
3474 | tree val; | |
3475 | ||
3476 | for (i = 0; i < 3; i++) | |
3477 | { | |
cf72f34d | 3478 | args[i] = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, i), |
1227ba74 | 3479 | lval, |
b2a43197 | 3480 | non_constant_p, overflow_p); |
09b42213 | 3481 | VERIFY_CONSTANT (args[i]); |
3482 | } | |
3483 | ||
3484 | val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t), | |
3485 | args[0], args[1], args[2]); | |
3486 | if (val == NULL_TREE) | |
3487 | return t; | |
3488 | VERIFY_CONSTANT (val); | |
3489 | return val; | |
3490 | } | |
3491 | ||
33603066 | 3492 | /* True if T was declared in a function declared to be constexpr, and |
3493 | therefore potentially constant in C++14. */ | |
3494 | ||
09b42213 | 3495 | bool |
3496 | var_in_constexpr_fn (tree t) | |
3497 | { | |
3498 | tree ctx = DECL_CONTEXT (t); | |
33603066 | 3499 | return (ctx && TREE_CODE (ctx) == FUNCTION_DECL |
09b42213 | 3500 | && DECL_DECLARED_CONSTEXPR_P (ctx)); |
3501 | } | |
3502 | ||
33603066 | 3503 | /* True if T was declared in a function that might be constexpr: either a |
3504 | function that was declared constexpr, or a C++17 lambda op(). */ | |
3505 | ||
3506 | bool | |
3507 | var_in_maybe_constexpr_fn (tree t) | |
3508 | { | |
40e2decb | 3509 | if (cxx_dialect >= cxx17 |
33603066 | 3510 | && DECL_FUNCTION_SCOPE_P (t) |
3511 | && LAMBDA_FUNCTION_P (DECL_CONTEXT (t))) | |
3512 | return true; | |
3513 | return var_in_constexpr_fn (t); | |
3514 | } | |
3515 | ||
93312944 | 3516 | /* We're assigning INIT to TARGET. In do_build_copy_constructor and |
3517 | build_over_call we implement trivial copy of a class with tail padding using | |
3518 | assignment of character arrays, which is valid in normal code, but not in | |
3519 | constexpr evaluation. We don't need to worry about clobbering tail padding | |
3520 | in constexpr evaluation, so strip the type punning. */ | |
3521 | ||
3522 | static void | |
3523 | maybe_simplify_trivial_copy (tree &target, tree &init) | |
3524 | { | |
3525 | if (TREE_CODE (target) == MEM_REF | |
3526 | && TREE_CODE (init) == MEM_REF | |
3527 | && TREE_TYPE (target) == TREE_TYPE (init) | |
3528 | && TREE_CODE (TREE_TYPE (target)) == ARRAY_TYPE | |
3529 | && TREE_TYPE (TREE_TYPE (target)) == unsigned_char_type_node) | |
3530 | { | |
3531 | target = build_fold_indirect_ref (TREE_OPERAND (target, 0)); | |
3532 | init = build_fold_indirect_ref (TREE_OPERAND (init, 0)); | |
3533 | } | |
3534 | } | |
3535 | ||
9c96033c | 3536 | /* Evaluate an INIT_EXPR or MODIFY_EXPR. */ |
3537 | ||
3538 | static tree | |
3539 | cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3540 | bool lval, |
9c96033c | 3541 | bool *non_constant_p, bool *overflow_p) |
3542 | { | |
3543 | constexpr_ctx new_ctx = *ctx; | |
3544 | ||
8a36d0ec | 3545 | tree init = TREE_OPERAND (t, 1); |
3546 | if (TREE_CLOBBER_P (init)) | |
3547 | /* Just ignore clobbers. */ | |
3548 | return void_node; | |
3549 | ||
9c96033c | 3550 | /* First we figure out where we're storing to. */ |
3551 | tree target = TREE_OPERAND (t, 0); | |
93312944 | 3552 | |
3553 | maybe_simplify_trivial_copy (target, init); | |
3554 | ||
9db9fc38 | 3555 | tree type = TREE_TYPE (target); |
9c96033c | 3556 | target = cxx_eval_constant_expression (ctx, target, |
f83e6885 | 3557 | true, |
b2a43197 | 3558 | non_constant_p, overflow_p); |
9c96033c | 3559 | if (*non_constant_p) |
3560 | return t; | |
3561 | ||
cf3cefc9 | 3562 | /* cxx_eval_array_reference for lval = true allows references one past |
3563 | end of array, because it does not know if it is just taking address | |
3564 | (which is valid), or actual dereference. Here we know it is | |
3565 | a dereference, so diagnose it here. */ | |
3566 | for (tree probe = target; probe; ) | |
3567 | { | |
3568 | switch (TREE_CODE (probe)) | |
3569 | { | |
3570 | case ARRAY_REF: | |
3571 | tree nelts, ary; | |
3572 | ary = TREE_OPERAND (probe, 0); | |
51f0c7e2 | 3573 | nelts = get_array_or_vector_nelts (ctx, TREE_TYPE (ary), |
3574 | non_constant_p, overflow_p); | |
cf3cefc9 | 3575 | VERIFY_CONSTANT (nelts); |
3576 | gcc_assert (TREE_CODE (nelts) == INTEGER_CST | |
3577 | && TREE_CODE (TREE_OPERAND (probe, 1)) == INTEGER_CST); | |
cb7bca5f | 3578 | if (wi::to_widest (TREE_OPERAND (probe, 1)) == wi::to_widest (nelts)) |
cf3cefc9 | 3579 | { |
3580 | diag_array_subscript (ctx, ary, TREE_OPERAND (probe, 1)); | |
3581 | *non_constant_p = true; | |
3582 | return t; | |
3583 | } | |
3584 | /* FALLTHRU */ | |
3585 | ||
3586 | case BIT_FIELD_REF: | |
3587 | case COMPONENT_REF: | |
3588 | probe = TREE_OPERAND (probe, 0); | |
3589 | continue; | |
3590 | ||
3591 | default: | |
3592 | probe = NULL_TREE; | |
3593 | continue; | |
3594 | } | |
3595 | } | |
3596 | ||
9db9fc38 | 3597 | if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (target), type)) |
3598 | { | |
3599 | /* For initialization of an empty base, the original target will be | |
3600 | *(base*)this, which the above evaluation resolves to the object | |
3601 | argument, which has the derived type rather than the base type. In | |
3602 | this situation, just evaluate the initializer and return, since | |
3603 | there's no actual data to store. */ | |
3604 | gcc_assert (is_empty_class (type)); | |
3605 | return cxx_eval_constant_expression (ctx, init, false, | |
3606 | non_constant_p, overflow_p); | |
3607 | } | |
3608 | ||
9c96033c | 3609 | /* And then find the underlying variable. */ |
3610 | vec<tree,va_gc> *refs = make_tree_vector(); | |
3611 | tree object = NULL_TREE; | |
3612 | for (tree probe = target; object == NULL_TREE; ) | |
3613 | { | |
3614 | switch (TREE_CODE (probe)) | |
3615 | { | |
3616 | case BIT_FIELD_REF: | |
3617 | case COMPONENT_REF: | |
3618 | case ARRAY_REF: | |
3619 | vec_safe_push (refs, TREE_OPERAND (probe, 1)); | |
3620 | vec_safe_push (refs, TREE_TYPE (probe)); | |
3621 | probe = TREE_OPERAND (probe, 0); | |
3622 | break; | |
3623 | ||
3624 | default: | |
3625 | object = probe; | |
9c96033c | 3626 | } |
3627 | } | |
3628 | ||
3629 | /* And then find/build up our initializer for the path to the subobject | |
3630 | we're initializing. */ | |
6fe83e54 | 3631 | tree *valp; |
43b7271d | 3632 | if (object == ctx->object && VAR_P (object) |
3633 | && DECL_NAME (object) && ctx->call == NULL) | |
3634 | /* The variable we're building up an aggregate initializer for is outside | |
3635 | the constant-expression, so don't evaluate the store. We check | |
3636 | DECL_NAME to handle TARGET_EXPR temporaries, which are fair game. */ | |
3637 | valp = NULL; | |
3638 | else if (DECL_P (object)) | |
6fe83e54 | 3639 | valp = ctx->values->get (object); |
3640 | else | |
3641 | valp = NULL; | |
9c96033c | 3642 | if (!valp) |
3643 | { | |
3644 | /* A constant-expression cannot modify objects from outside the | |
3645 | constant-expression. */ | |
f83e6885 | 3646 | if (!ctx->quiet) |
ea034e2c | 3647 | error ("modification of %qE is not a constant expression", object); |
9c96033c | 3648 | *non_constant_p = true; |
3649 | return t; | |
3650 | } | |
9db9fc38 | 3651 | type = TREE_TYPE (object); |
a02b42fe | 3652 | bool no_zero_init = true; |
58b0f9ce | 3653 | |
3654 | vec<tree,va_gc> *ctors = make_tree_vector (); | |
9c96033c | 3655 | while (!refs->is_empty()) |
3656 | { | |
3657 | if (*valp == NULL_TREE) | |
3658 | { | |
3659 | *valp = build_constructor (type, NULL); | |
165d0d5b | 3660 | CONSTRUCTOR_NO_CLEARING (*valp) = no_zero_init; |
9c96033c | 3661 | } |
92fe8840 | 3662 | else if (TREE_CODE (*valp) == STRING_CST) |
3663 | { | |
3664 | /* An array was initialized with a string constant, and now | |
3665 | we're writing into one of its elements. Explode the | |
3666 | single initialization into a set of element | |
3667 | initializations. */ | |
3668 | gcc_assert (TREE_CODE (type) == ARRAY_TYPE); | |
3669 | ||
3670 | tree string = *valp; | |
3671 | tree elt_type = TREE_TYPE (type); | |
3672 | unsigned chars_per_elt = (TYPE_PRECISION (elt_type) | |
3673 | / TYPE_PRECISION (char_type_node)); | |
3674 | unsigned num_elts = TREE_STRING_LENGTH (string) / chars_per_elt; | |
3675 | tree ary_ctor = build_constructor (type, NULL); | |
3676 | ||
3677 | vec_safe_reserve (CONSTRUCTOR_ELTS (ary_ctor), num_elts); | |
3678 | for (unsigned ix = 0; ix != num_elts; ix++) | |
3679 | { | |
3680 | constructor_elt elt = | |
3681 | { | |
3682 | build_int_cst (size_type_node, ix), | |
3683 | extract_string_elt (string, chars_per_elt, ix) | |
3684 | }; | |
3685 | CONSTRUCTOR_ELTS (ary_ctor)->quick_push (elt); | |
3686 | } | |
3687 | ||
3688 | *valp = ary_ctor; | |
3689 | } | |
3690 | ||
a02b42fe | 3691 | /* If the value of object is already zero-initialized, any new ctors for |
3692 | subobjects will also be zero-initialized. */ | |
165d0d5b | 3693 | no_zero_init = CONSTRUCTOR_NO_CLEARING (*valp); |
9c96033c | 3694 | |
58b0f9ce | 3695 | vec_safe_push (ctors, *valp); |
3696 | ||
7963b19d | 3697 | enum tree_code code = TREE_CODE (type); |
9c96033c | 3698 | type = refs->pop(); |
7963b19d | 3699 | tree index = refs->pop(); |
9c96033c | 3700 | |
9c96033c | 3701 | constructor_elt *cep = NULL; |
7963b19d | 3702 | if (code == ARRAY_TYPE) |
3703 | { | |
3704 | HOST_WIDE_INT i | |
3705 | = find_array_ctor_elt (*valp, index, /*insert*/true); | |
3706 | gcc_assert (i >= 0); | |
3707 | cep = CONSTRUCTOR_ELT (*valp, i); | |
3708 | gcc_assert (TREE_CODE (cep->index) != RANGE_EXPR); | |
3709 | } | |
3710 | else | |
3711 | { | |
3712 | gcc_assert (TREE_CODE (index) == FIELD_DECL); | |
13ee2de7 | 3713 | |
3714 | /* We must keep the CONSTRUCTOR's ELTS in FIELD order. | |
3715 | Usually we meet initializers in that order, but it is | |
3716 | possible for base types to be placed not in program | |
3717 | order. */ | |
3718 | tree fields = TYPE_FIELDS (DECL_CONTEXT (index)); | |
3719 | unsigned HOST_WIDE_INT idx; | |
3720 | ||
ef782365 | 3721 | if (code == UNION_TYPE && CONSTRUCTOR_NELTS (*valp) |
3722 | && CONSTRUCTOR_ELT (*valp, 0)->index != index) | |
3723 | /* Changing active member. */ | |
3724 | vec_safe_truncate (CONSTRUCTOR_ELTS (*valp), 0); | |
3725 | ||
13ee2de7 | 3726 | for (idx = 0; |
7963b19d | 3727 | vec_safe_iterate (CONSTRUCTOR_ELTS (*valp), idx, &cep); |
13ee2de7 | 3728 | idx++, fields = DECL_CHAIN (fields)) |
7963b19d | 3729 | { |
13ee2de7 | 3730 | if (index == cep->index) |
3731 | goto found; | |
3732 | ||
3733 | /* The field we're initializing must be on the field | |
3734 | list. Look to see if it is present before the | |
3735 | field the current ELT initializes. */ | |
3736 | for (; fields != cep->index; fields = DECL_CHAIN (fields)) | |
3737 | if (index == fields) | |
3738 | goto insert; | |
7963b19d | 3739 | } |
13ee2de7 | 3740 | |
3741 | /* We fell off the end of the CONSTRUCTOR, so insert a new | |
3742 | entry at the end. */ | |
3743 | insert: | |
3744 | { | |
3745 | constructor_elt ce = { index, NULL_TREE }; | |
3746 | ||
3747 | vec_safe_insert (CONSTRUCTOR_ELTS (*valp), idx, ce); | |
3748 | cep = CONSTRUCTOR_ELT (*valp, idx); | |
3749 | } | |
3750 | found:; | |
7963b19d | 3751 | } |
9c96033c | 3752 | valp = &cep->value; |
3753 | } | |
3754 | release_tree_vector (refs); | |
3755 | ||
469dc5a6 | 3756 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) |
9c96033c | 3757 | { |
3758 | /* Create a new CONSTRUCTOR in case evaluation of the initializer | |
3759 | wants to modify it. */ | |
469dc5a6 | 3760 | if (*valp == NULL_TREE) |
6cded085 | 3761 | { |
6993e708 | 3762 | *valp = build_constructor (type, NULL); |
165d0d5b | 3763 | CONSTRUCTOR_NO_CLEARING (*valp) = no_zero_init; |
6cded085 | 3764 | } |
6993e708 | 3765 | else if (TREE_CODE (*valp) == PTRMEM_CST) |
3766 | *valp = cplus_expand_constant (*valp); | |
3767 | new_ctx.ctor = *valp; | |
9c96033c | 3768 | new_ctx.object = target; |
3769 | } | |
3770 | ||
8a36d0ec | 3771 | init = cxx_eval_constant_expression (&new_ctx, init, false, |
3772 | non_constant_p, overflow_p); | |
7b9f713d | 3773 | /* Don't share a CONSTRUCTOR that might be changed later. */ |
e283bb4f | 3774 | init = unshare_constructor (init); |
9c96033c | 3775 | if (target == object) |
5579a199 | 3776 | /* The hash table might have moved since the get earlier. */ |
3777 | valp = ctx->values->get (object); | |
3778 | ||
3779 | if (TREE_CODE (init) == CONSTRUCTOR) | |
469dc5a6 | 3780 | { |
5579a199 | 3781 | /* An outer ctx->ctor might be pointing to *valp, so replace |
3782 | its contents. */ | |
3783 | CONSTRUCTOR_ELTS (*valp) = CONSTRUCTOR_ELTS (init); | |
3784 | TREE_CONSTANT (*valp) = TREE_CONSTANT (init); | |
3785 | TREE_SIDE_EFFECTS (*valp) = TREE_SIDE_EFFECTS (init); | |
165d0d5b | 3786 | CONSTRUCTOR_NO_CLEARING (*valp) |
3787 | = CONSTRUCTOR_NO_CLEARING (init); | |
469dc5a6 | 3788 | } |
9c96033c | 3789 | else |
5579a199 | 3790 | *valp = init; |
58b0f9ce | 3791 | |
5579a199 | 3792 | /* Update TREE_CONSTANT and TREE_SIDE_EFFECTS on enclosing |
3793 | CONSTRUCTORs, if any. */ | |
3794 | tree elt; | |
3795 | unsigned i; | |
3796 | bool c = TREE_CONSTANT (init); | |
3797 | bool s = TREE_SIDE_EFFECTS (init); | |
3798 | if (!c || s) | |
3799 | FOR_EACH_VEC_SAFE_ELT (ctors, i, elt) | |
3800 | { | |
3801 | if (!c) | |
3802 | TREE_CONSTANT (elt) = false; | |
3803 | if (s) | |
3804 | TREE_SIDE_EFFECTS (elt) = true; | |
3805 | } | |
58b0f9ce | 3806 | release_tree_vector (ctors); |
9c96033c | 3807 | |
3808 | if (*non_constant_p) | |
3809 | return t; | |
1227ba74 | 3810 | else if (lval) |
9c96033c | 3811 | return target; |
3812 | else | |
dfac7dd2 | 3813 | return init; |
9c96033c | 3814 | } |
3815 | ||
3816 | /* Evaluate a ++ or -- expression. */ | |
3817 | ||
3818 | static tree | |
3819 | cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3820 | bool lval, |
9c96033c | 3821 | bool *non_constant_p, bool *overflow_p) |
3822 | { | |
3823 | enum tree_code code = TREE_CODE (t); | |
3824 | tree type = TREE_TYPE (t); | |
3825 | tree op = TREE_OPERAND (t, 0); | |
3826 | tree offset = TREE_OPERAND (t, 1); | |
3827 | gcc_assert (TREE_CONSTANT (offset)); | |
3828 | ||
3829 | /* The operand as an lvalue. */ | |
f83e6885 | 3830 | op = cxx_eval_constant_expression (ctx, op, true, |
b2a43197 | 3831 | non_constant_p, overflow_p); |
9c96033c | 3832 | |
3833 | /* The operand as an rvalue. */ | |
c017458d | 3834 | tree val |
3835 | = cxx_eval_constant_expression (ctx, op, false, | |
3836 | non_constant_p, overflow_p); | |
35f2c28f | 3837 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
3838 | a local array in a constexpr function. */ | |
d03fa520 | 3839 | bool ptr = INDIRECT_TYPE_P (TREE_TYPE (val)); |
35f2c28f | 3840 | if (!ptr) |
3841 | VERIFY_CONSTANT (val); | |
9c96033c | 3842 | |
3843 | /* The modified value. */ | |
3844 | bool inc = (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR); | |
c8a8f7ad | 3845 | tree mod; |
d03fa520 | 3846 | if (INDIRECT_TYPE_P (type)) |
c8a8f7ad | 3847 | { |
3848 | /* The middle end requires pointers to use POINTER_PLUS_EXPR. */ | |
3849 | offset = convert_to_ptrofftype (offset); | |
3850 | if (!inc) | |
3851 | offset = fold_build1 (NEGATE_EXPR, TREE_TYPE (offset), offset); | |
3852 | mod = fold_build2 (POINTER_PLUS_EXPR, type, val, offset); | |
3853 | } | |
3854 | else | |
3855 | mod = fold_build2 (inc ? PLUS_EXPR : MINUS_EXPR, type, val, offset); | |
35f2c28f | 3856 | if (!ptr) |
3857 | VERIFY_CONSTANT (mod); | |
9c96033c | 3858 | |
3859 | /* Storing the modified value. */ | |
3860 | tree store = build2 (MODIFY_EXPR, type, op, mod); | |
f83e6885 | 3861 | cxx_eval_constant_expression (ctx, store, |
b2a43197 | 3862 | true, non_constant_p, overflow_p); |
9c96033c | 3863 | |
3864 | /* And the value of the expression. */ | |
3865 | if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) | |
3866 | { | |
3867 | /* Prefix ops are lvalues. */ | |
1227ba74 | 3868 | if (lval) |
9c96033c | 3869 | return op; |
3870 | else | |
3871 | /* But we optimize when the caller wants an rvalue. */ | |
3872 | return mod; | |
3873 | } | |
3874 | else | |
3875 | /* Postfix ops are rvalues. */ | |
3876 | return val; | |
3877 | } | |
3878 | ||
00f21715 | 3879 | /* Predicates for the meaning of *jump_target. */ |
3880 | ||
3881 | static bool | |
3882 | returns (tree *jump_target) | |
3883 | { | |
3884 | return *jump_target | |
d29e4e8c | 3885 | && (TREE_CODE (*jump_target) == RETURN_EXPR |
3886 | || (TREE_CODE (*jump_target) == LABEL_DECL | |
3887 | && LABEL_DECL_CDTOR (*jump_target))); | |
00f21715 | 3888 | } |
3889 | ||
3890 | static bool | |
3891 | breaks (tree *jump_target) | |
3892 | { | |
3893 | return *jump_target | |
cf03ba19 | 3894 | && ((TREE_CODE (*jump_target) == LABEL_DECL |
3895 | && LABEL_DECL_BREAK (*jump_target)) | |
3896 | || TREE_CODE (*jump_target) == EXIT_EXPR); | |
00f21715 | 3897 | } |
3898 | ||
3899 | static bool | |
3900 | continues (tree *jump_target) | |
3901 | { | |
3902 | return *jump_target | |
3903 | && TREE_CODE (*jump_target) == LABEL_DECL | |
3904 | && LABEL_DECL_CONTINUE (*jump_target); | |
3905 | } | |
3906 | ||
3907 | static bool | |
3908 | switches (tree *jump_target) | |
3909 | { | |
3910 | return *jump_target | |
3911 | && TREE_CODE (*jump_target) == INTEGER_CST; | |
3912 | } | |
3913 | ||
3914 | /* Subroutine of cxx_eval_statement_list. Determine whether the statement | |
2a2770c6 | 3915 | STMT matches *jump_target. If we're looking for a case label and we see |
3916 | the default label, note it in ctx->css_state. */ | |
00f21715 | 3917 | |
3918 | static bool | |
2a2770c6 | 3919 | label_matches (const constexpr_ctx *ctx, tree *jump_target, tree stmt) |
00f21715 | 3920 | { |
00f21715 | 3921 | switch (TREE_CODE (*jump_target)) |
3922 | { | |
3923 | case LABEL_DECL: | |
3924 | if (TREE_CODE (stmt) == LABEL_EXPR | |
3925 | && LABEL_EXPR_LABEL (stmt) == *jump_target) | |
3926 | return true; | |
3927 | break; | |
3928 | ||
3929 | case INTEGER_CST: | |
3930 | if (TREE_CODE (stmt) == CASE_LABEL_EXPR) | |
3931 | { | |
2a2770c6 | 3932 | gcc_assert (ctx->css_state != NULL); |
00f21715 | 3933 | if (!CASE_LOW (stmt)) |
2a2770c6 | 3934 | { |
3935 | /* default: should appear just once in a SWITCH_EXPR | |
3936 | body (excluding nested SWITCH_EXPR). */ | |
3937 | gcc_assert (*ctx->css_state != css_default_seen); | |
3938 | /* When evaluating SWITCH_EXPR body for the second time, | |
3939 | return true for the default: label. */ | |
3940 | if (*ctx->css_state == css_default_processing) | |
3941 | return true; | |
3942 | *ctx->css_state = css_default_seen; | |
3943 | } | |
83c375ba | 3944 | else if (CASE_HIGH (stmt)) |
3945 | { | |
3946 | if (tree_int_cst_le (CASE_LOW (stmt), *jump_target) | |
3947 | && tree_int_cst_le (*jump_target, CASE_HIGH (stmt))) | |
3948 | return true; | |
3949 | } | |
00f21715 | 3950 | else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt))) |
3951 | return true; | |
3952 | } | |
3953 | break; | |
3954 | ||
3955 | default: | |
3956 | gcc_unreachable (); | |
3957 | } | |
3958 | return false; | |
3959 | } | |
3960 | ||
3961 | /* Evaluate a STATEMENT_LIST for side-effects. Handles various jump | |
3962 | semantics, for switch, break, continue, and return. */ | |
3963 | ||
3964 | static tree | |
3965 | cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3966 | bool *non_constant_p, bool *overflow_p, |
3967 | tree *jump_target) | |
3968 | { | |
3969 | tree_stmt_iterator i; | |
da7981e0 | 3970 | tree local_target; |
efea7c64 | 3971 | /* In a statement-expression we want to return the last value. |
3972 | For empty statement expression return void_node. */ | |
3973 | tree r = void_node; | |
da7981e0 | 3974 | if (!jump_target) |
3975 | { | |
3976 | local_target = NULL_TREE; | |
3977 | jump_target = &local_target; | |
3978 | } | |
00f21715 | 3979 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) |
3980 | { | |
00f21715 | 3981 | tree stmt = tsi_stmt (i); |
ba0f90e4 | 3982 | /* We've found a continue, so skip everything until we reach |
3983 | the label its jumping to. */ | |
3984 | if (continues (jump_target)) | |
3985 | { | |
3986 | if (label_matches (ctx, jump_target, stmt)) | |
3987 | /* Found it. */ | |
3988 | *jump_target = NULL_TREE; | |
3989 | else | |
3990 | continue; | |
3991 | } | |
442c4003 | 3992 | if (TREE_CODE (stmt) == DEBUG_BEGIN_STMT) |
3993 | continue; | |
da7981e0 | 3994 | r = cxx_eval_constant_expression (ctx, stmt, false, |
3995 | non_constant_p, overflow_p, | |
3996 | jump_target); | |
00f21715 | 3997 | if (*non_constant_p) |
3998 | break; | |
3999 | if (returns (jump_target) || breaks (jump_target)) | |
4000 | break; | |
4001 | } | |
da7981e0 | 4002 | return r; |
00f21715 | 4003 | } |
4004 | ||
4005 | /* Evaluate a LOOP_EXPR for side-effects. Handles break and return | |
4006 | semantics; continue semantics are covered by cxx_eval_statement_list. */ | |
4007 | ||
4008 | static tree | |
4009 | cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 4010 | bool *non_constant_p, bool *overflow_p, |
4011 | tree *jump_target) | |
4012 | { | |
2631cb67 | 4013 | constexpr_ctx new_ctx = *ctx; |
4014 | ||
00f21715 | 4015 | tree body = TREE_OPERAND (t, 0); |
21483ab7 | 4016 | int count = 0; |
5370eb8d | 4017 | do |
00f21715 | 4018 | { |
2631cb67 | 4019 | hash_set<tree> save_exprs; |
4020 | new_ctx.save_exprs = &save_exprs; | |
4021 | ||
cf03ba19 | 4022 | cxx_eval_constant_expression (&new_ctx, body, /*lval*/false, |
4023 | non_constant_p, overflow_p, jump_target); | |
2631cb67 | 4024 | |
4025 | /* Forget saved values of SAVE_EXPRs. */ | |
4026 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
4027 | iter != save_exprs.end(); ++iter) | |
4028 | new_ctx.values->remove (*iter); | |
21483ab7 | 4029 | if (++count >= constexpr_loop_limit) |
4030 | { | |
4031 | if (!ctx->quiet) | |
d3a3cfb8 | 4032 | error_at (cp_expr_loc_or_loc (t, input_location), |
5967b28b | 4033 | "%<constexpr%> loop iteration count exceeds limit of %d " |
21483ab7 | 4034 | "(use -fconstexpr-loop-limit= to increase the limit)", |
4035 | constexpr_loop_limit); | |
4036 | *non_constant_p = true; | |
4037 | break; | |
4038 | } | |
00f21715 | 4039 | } |
2a2770c6 | 4040 | while (!returns (jump_target) |
4041 | && !breaks (jump_target) | |
4042 | && !switches (jump_target) | |
4043 | && !*non_constant_p); | |
5370eb8d | 4044 | |
00f21715 | 4045 | if (breaks (jump_target)) |
4046 | *jump_target = NULL_TREE; | |
2631cb67 | 4047 | |
00f21715 | 4048 | return NULL_TREE; |
4049 | } | |
4050 | ||
4051 | /* Evaluate a SWITCH_EXPR for side-effects. Handles switch and break jump | |
4052 | semantics. */ | |
4053 | ||
4054 | static tree | |
4055 | cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 4056 | bool *non_constant_p, bool *overflow_p, |
4057 | tree *jump_target) | |
4058 | { | |
4059 | tree cond = TREE_OPERAND (t, 0); | |
f83e6885 | 4060 | cond = cxx_eval_constant_expression (ctx, cond, false, |
b2a43197 | 4061 | non_constant_p, overflow_p); |
00f21715 | 4062 | VERIFY_CONSTANT (cond); |
4063 | *jump_target = cond; | |
4064 | ||
4065 | tree body = TREE_OPERAND (t, 1); | |
2a2770c6 | 4066 | constexpr_ctx new_ctx = *ctx; |
4067 | constexpr_switch_state css = css_default_not_seen; | |
4068 | new_ctx.css_state = &css; | |
4069 | cxx_eval_constant_expression (&new_ctx, body, false, | |
4070 | non_constant_p, overflow_p, jump_target); | |
4071 | if (switches (jump_target) && css == css_default_seen) | |
4072 | { | |
4073 | /* If the SWITCH_EXPR body has default: label, process it once again, | |
4074 | this time instructing label_matches to return true for default: | |
4075 | label on switches (jump_target). */ | |
4076 | css = css_default_processing; | |
4077 | cxx_eval_constant_expression (&new_ctx, body, false, | |
4078 | non_constant_p, overflow_p, jump_target); | |
4079 | } | |
00f21715 | 4080 | if (breaks (jump_target) || switches (jump_target)) |
4081 | *jump_target = NULL_TREE; | |
4082 | return NULL_TREE; | |
4083 | } | |
4084 | ||
85de9604 | 4085 | /* Find the object of TYPE under initialization in CTX. */ |
4086 | ||
4087 | static tree | |
4088 | lookup_placeholder (const constexpr_ctx *ctx, bool lval, tree type) | |
4089 | { | |
def8e41f | 4090 | if (!ctx) |
85de9604 | 4091 | return NULL_TREE; |
4092 | ||
4093 | /* We could use ctx->object unconditionally, but using ctx->ctor when we | |
4094 | can is a minor optimization. */ | |
def8e41f | 4095 | if (!lval && ctx->ctor && same_type_p (TREE_TYPE (ctx->ctor), type)) |
85de9604 | 4096 | return ctx->ctor; |
4097 | ||
def8e41f | 4098 | if (!ctx->object) |
4099 | return NULL_TREE; | |
4100 | ||
85de9604 | 4101 | /* Since an object cannot have a field of its own type, we can search outward |
4102 | from ctx->object to find the unique containing object of TYPE. */ | |
4103 | tree ob = ctx->object; | |
4104 | while (ob) | |
4105 | { | |
4106 | if (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (ob), type)) | |
4107 | break; | |
4108 | if (handled_component_p (ob)) | |
4109 | ob = TREE_OPERAND (ob, 0); | |
4110 | else | |
4111 | ob = NULL_TREE; | |
4112 | } | |
4113 | ||
4114 | return ob; | |
4115 | } | |
4116 | ||
09b42213 | 4117 | /* Attempt to reduce the expression T to a constant value. |
4118 | On failure, issue diagnostic and return error_mark_node. */ | |
4119 | /* FIXME unify with c_fully_fold */ | |
9c96033c | 4120 | /* FIXME overflow_p is too global */ |
09b42213 | 4121 | |
4122 | static tree | |
cf72f34d | 4123 | cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 4124 | bool lval, |
00f21715 | 4125 | bool *non_constant_p, bool *overflow_p, |
4126 | tree *jump_target) | |
09b42213 | 4127 | { |
cf72f34d | 4128 | constexpr_ctx new_ctx; |
09b42213 | 4129 | tree r = t; |
4130 | ||
2a2770c6 | 4131 | if (jump_target && *jump_target) |
4132 | { | |
4133 | /* If we are jumping, ignore all statements/expressions except those | |
4134 | that could have LABEL_EXPR or CASE_LABEL_EXPR in their bodies. */ | |
4135 | switch (TREE_CODE (t)) | |
4136 | { | |
4137 | case BIND_EXPR: | |
4138 | case STATEMENT_LIST: | |
4139 | case LOOP_EXPR: | |
4140 | case COND_EXPR: | |
4141 | break; | |
4142 | case LABEL_EXPR: | |
4143 | case CASE_LABEL_EXPR: | |
4144 | if (label_matches (ctx, jump_target, t)) | |
4145 | /* Found it. */ | |
4146 | *jump_target = NULL_TREE; | |
4147 | return NULL_TREE; | |
4148 | default: | |
4149 | return NULL_TREE; | |
4150 | } | |
4151 | } | |
09b42213 | 4152 | if (t == error_mark_node) |
4153 | { | |
4154 | *non_constant_p = true; | |
4155 | return t; | |
4156 | } | |
4157 | if (CONSTANT_CLASS_P (t)) | |
4158 | { | |
c4fa85c9 | 4159 | if (TREE_OVERFLOW (t)) |
4160 | { | |
4161 | if (!ctx->quiet) | |
4162 | permerror (input_location, "overflow in constant expression"); | |
4163 | if (!flag_permissive || ctx->quiet) | |
4164 | *overflow_p = true; | |
4165 | } | |
cb768824 | 4166 | |
4167 | if (TREE_CODE (t) == INTEGER_CST | |
90ad495b | 4168 | && TYPE_PTR_P (TREE_TYPE (t)) |
cb768824 | 4169 | && !integer_zerop (t)) |
4170 | { | |
4171 | if (!ctx->quiet) | |
4172 | error ("value %qE of type %qT is not a constant expression", | |
4173 | t, TREE_TYPE (t)); | |
4174 | *non_constant_p = true; | |
4175 | } | |
4176 | ||
09b42213 | 4177 | return t; |
4178 | } | |
09b42213 | 4179 | |
cb768824 | 4180 | tree_code tcode = TREE_CODE (t); |
4181 | switch (tcode) | |
09b42213 | 4182 | { |
9c96033c | 4183 | case RESULT_DECL: |
1227ba74 | 4184 | if (lval) |
9c96033c | 4185 | return t; |
4186 | /* We ask for an rvalue for the RESULT_DECL when indirecting | |
92a9c89e | 4187 | through an invisible reference, or in named return value |
4188 | optimization. */ | |
8ea8d065 | 4189 | if (tree *p = ctx->values->get (t)) |
4190 | return *p; | |
4191 | else | |
4192 | { | |
4193 | if (!ctx->quiet) | |
4194 | error ("%qE is not a constant expression", t); | |
4195 | *non_constant_p = true; | |
4196 | } | |
4197 | break; | |
9c96033c | 4198 | |
09b42213 | 4199 | case VAR_DECL: |
9c8aeb66 | 4200 | if (DECL_HAS_VALUE_EXPR_P (t)) |
33603066 | 4201 | return cxx_eval_constant_expression (ctx, DECL_VALUE_EXPR (t), |
4202 | lval, non_constant_p, overflow_p); | |
e3533433 | 4203 | /* fall through */ |
8b2b2f24 | 4204 | case CONST_DECL: |
4205 | /* We used to not check lval for CONST_DECL, but darwin.c uses | |
4206 | CONST_DECL for aggregate constants. */ | |
1227ba74 | 4207 | if (lval) |
09b42213 | 4208 | return t; |
594cc00c | 4209 | if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
4210 | && is_really_empty_class (TREE_TYPE (t))) | |
c7282bf2 | 4211 | { |
4212 | /* If the class is empty, we aren't actually loading anything. */ | |
4213 | r = build_constructor (TREE_TYPE (t), NULL); | |
4214 | TREE_CONSTANT (r) = true; | |
4215 | } | |
4216 | else if (ctx->strict) | |
2055d27a | 4217 | r = decl_really_constant_value (t); |
4218 | else | |
4219 | r = decl_constant_value (t); | |
09b42213 | 4220 | if (TREE_CODE (r) == TARGET_EXPR |
4221 | && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR) | |
4222 | r = TARGET_EXPR_INITIAL (r); | |
f4ae4202 | 4223 | if (VAR_P (r)) |
cf72f34d | 4224 | if (tree *p = ctx->values->get (r)) |
a143e277 | 4225 | if (*p != NULL_TREE) |
4226 | r = *p; | |
09b42213 | 4227 | if (DECL_P (r)) |
4228 | { | |
f83e6885 | 4229 | if (!ctx->quiet) |
09b42213 | 4230 | non_const_var_error (r); |
4231 | *non_constant_p = true; | |
4232 | } | |
4233 | break; | |
4234 | ||
90567983 | 4235 | case DEBUG_BEGIN_STMT: |
4236 | /* ??? It might be nice to retain this information somehow, so | |
4237 | as to be able to step into a constexpr function call. */ | |
4238 | /* Fall through. */ | |
4239 | ||
09b42213 | 4240 | case FUNCTION_DECL: |
4241 | case TEMPLATE_DECL: | |
4242 | case LABEL_DECL: | |
00f21715 | 4243 | case LABEL_EXPR: |
4244 | case CASE_LABEL_EXPR: | |
2a2770c6 | 4245 | case PREDICT_EXPR: |
09b42213 | 4246 | return t; |
4247 | ||
4248 | case PARM_DECL: | |
90ad495b | 4249 | if (lval && !TYPE_REF_P (TREE_TYPE (t))) |
9c96033c | 4250 | /* glvalue use. */; |
4251 | else if (tree *p = ctx->values->get (r)) | |
4252 | r = *p; | |
1227ba74 | 4253 | else if (lval) |
09b42213 | 4254 | /* Defer in case this is only used for its type. */; |
90ad495b | 4255 | else if (TYPE_REF_P (TREE_TYPE (t))) |
1eb418cc | 4256 | /* Defer, there's no lvalue->rvalue conversion. */; |
53d2f3de | 4257 | else if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
4258 | && is_really_empty_class (TREE_TYPE (t))) | |
a6613de7 | 4259 | { |
4260 | /* If the class is empty, we aren't actually loading anything. */ | |
4261 | r = build_constructor (TREE_TYPE (t), NULL); | |
4262 | TREE_CONSTANT (r) = true; | |
4263 | } | |
09b42213 | 4264 | else |
4265 | { | |
f83e6885 | 4266 | if (!ctx->quiet) |
09b42213 | 4267 | error ("%qE is not a constant expression", t); |
4268 | *non_constant_p = true; | |
4269 | } | |
4270 | break; | |
4271 | ||
4272 | case CALL_EXPR: | |
4273 | case AGGR_INIT_EXPR: | |
1227ba74 | 4274 | r = cxx_eval_call_expression (ctx, t, lval, |
09b42213 | 4275 | non_constant_p, overflow_p); |
4276 | break; | |
4277 | ||
9c96033c | 4278 | case DECL_EXPR: |
4279 | { | |
4280 | r = DECL_EXPR_DECL (t); | |
4281 | if (AGGREGATE_TYPE_P (TREE_TYPE (r)) | |
4282 | || VECTOR_TYPE_P (TREE_TYPE (r))) | |
4283 | { | |
4284 | new_ctx = *ctx; | |
4285 | new_ctx.object = r; | |
4286 | new_ctx.ctor = build_constructor (TREE_TYPE (r), NULL); | |
165d0d5b | 4287 | CONSTRUCTOR_NO_CLEARING (new_ctx.ctor) = true; |
9c96033c | 4288 | new_ctx.values->put (r, new_ctx.ctor); |
4289 | ctx = &new_ctx; | |
4290 | } | |
4291 | ||
4292 | if (tree init = DECL_INITIAL (r)) | |
4293 | { | |
4294 | init = cxx_eval_constant_expression (ctx, init, | |
f83e6885 | 4295 | false, |
b2a43197 | 4296 | non_constant_p, overflow_p); |
5898f0d7 | 4297 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 4298 | init = unshare_constructor (init); |
9c96033c | 4299 | ctx->values->put (r, init); |
4300 | } | |
4301 | else if (ctx == &new_ctx) | |
4302 | /* We gave it a CONSTRUCTOR above. */; | |
4303 | else | |
4304 | ctx->values->put (r, NULL_TREE); | |
4305 | } | |
4306 | break; | |
4307 | ||
09b42213 | 4308 | case TARGET_EXPR: |
4309 | if (!literal_type_p (TREE_TYPE (t))) | |
4310 | { | |
f83e6885 | 4311 | if (!ctx->quiet) |
09b42213 | 4312 | { |
bc35ef65 | 4313 | auto_diagnostic_group d; |
09b42213 | 4314 | error ("temporary of non-literal type %qT in a " |
4315 | "constant expression", TREE_TYPE (t)); | |
4316 | explain_non_literal_class (TREE_TYPE (t)); | |
4317 | } | |
4318 | *non_constant_p = true; | |
4319 | break; | |
4320 | } | |
cf72f34d | 4321 | if ((AGGREGATE_TYPE_P (TREE_TYPE (t)) || VECTOR_TYPE_P (TREE_TYPE (t)))) |
4322 | { | |
4323 | /* We're being expanded without an explicit target, so start | |
4324 | initializing a new object; expansion with an explicit target | |
4325 | strips the TARGET_EXPR before we get here. */ | |
4326 | new_ctx = *ctx; | |
4327 | new_ctx.ctor = build_constructor (TREE_TYPE (t), NULL); | |
165d0d5b | 4328 | CONSTRUCTOR_NO_CLEARING (new_ctx.ctor) = true; |
cf72f34d | 4329 | new_ctx.object = TARGET_EXPR_SLOT (t); |
4330 | ctx->values->put (new_ctx.object, new_ctx.ctor); | |
4331 | ctx = &new_ctx; | |
4332 | } | |
1227ba74 | 4333 | /* Pass false for 'lval' because this indicates |
09b42213 | 4334 | initialization of a temporary. */ |
cf72f34d | 4335 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 4336 | false, |
b2a43197 | 4337 | non_constant_p, overflow_p); |
09b42213 | 4338 | if (!*non_constant_p) |
4339 | /* Adjust the type of the result to the type of the temporary. */ | |
4340 | r = adjust_temp_type (TREE_TYPE (t), r); | |
1227ba74 | 4341 | if (lval) |
1eb418cc | 4342 | { |
4343 | tree slot = TARGET_EXPR_SLOT (t); | |
e283bb4f | 4344 | r = unshare_constructor (r); |
1eb418cc | 4345 | ctx->values->put (slot, r); |
4346 | return slot; | |
4347 | } | |
09b42213 | 4348 | break; |
4349 | ||
9c96033c | 4350 | case INIT_EXPR: |
9c96033c | 4351 | case MODIFY_EXPR: |
2a2770c6 | 4352 | gcc_assert (jump_target == NULL || *jump_target == NULL_TREE); |
1227ba74 | 4353 | r = cxx_eval_store_expression (ctx, t, lval, |
9c96033c | 4354 | non_constant_p, overflow_p); |
4355 | break; | |
4356 | ||
09b42213 | 4357 | case SCOPE_REF: |
cf72f34d | 4358 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 4359 | lval, |
b2a43197 | 4360 | non_constant_p, overflow_p); |
09b42213 | 4361 | break; |
4362 | ||
4363 | case RETURN_EXPR: | |
10fb495c | 4364 | if (TREE_OPERAND (t, 0) != NULL_TREE) |
4365 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
4366 | lval, | |
4367 | non_constant_p, overflow_p); | |
2c572f5f | 4368 | if (jump_target) |
4369 | *jump_target = t; | |
4370 | else | |
4371 | { | |
4372 | /* Can happen with ({ return true; }) && false; passed to | |
4373 | maybe_constant_value. There is nothing to jump over in this | |
4374 | case, and the bug will be diagnosed later. */ | |
4375 | gcc_assert (ctx->quiet); | |
4376 | *non_constant_p = true; | |
4377 | } | |
00f21715 | 4378 | break; |
4379 | ||
e0e672a0 | 4380 | case SAVE_EXPR: |
4381 | /* Avoid evaluating a SAVE_EXPR more than once. */ | |
4382 | if (tree *p = ctx->values->get (t)) | |
4383 | r = *p; | |
4384 | else | |
4385 | { | |
c8f6aeb1 | 4386 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), false, |
e0e672a0 | 4387 | non_constant_p, overflow_p); |
4388 | ctx->values->put (t, r); | |
2631cb67 | 4389 | if (ctx->save_exprs) |
4390 | ctx->save_exprs->add (t); | |
e0e672a0 | 4391 | } |
4392 | break; | |
4393 | ||
09b42213 | 4394 | case NON_LVALUE_EXPR: |
4395 | case TRY_CATCH_EXPR: | |
7f67d68c | 4396 | case TRY_BLOCK: |
09b42213 | 4397 | case CLEANUP_POINT_EXPR: |
4398 | case MUST_NOT_THROW_EXPR: | |
9c96033c | 4399 | case EXPR_STMT: |
4400 | case EH_SPEC_BLOCK: | |
cf72f34d | 4401 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 4402 | lval, |
00f21715 | 4403 | non_constant_p, overflow_p, |
4404 | jump_target); | |
09b42213 | 4405 | break; |
4406 | ||
7f67d68c | 4407 | case TRY_FINALLY_EXPR: |
4408 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4409 | non_constant_p, overflow_p, | |
4410 | jump_target); | |
4411 | if (!*non_constant_p) | |
4412 | /* Also evaluate the cleanup. */ | |
4413 | cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), true, | |
4414 | non_constant_p, overflow_p, | |
4415 | jump_target); | |
4416 | break; | |
4417 | ||
09b42213 | 4418 | /* These differ from cxx_eval_unary_expression in that this doesn't |
4419 | check for a constant operand or result; an address can be | |
4420 | constant without its operand being, and vice versa. */ | |
d2c63826 | 4421 | case MEM_REF: |
09b42213 | 4422 | case INDIRECT_REF: |
1227ba74 | 4423 | r = cxx_eval_indirect_ref (ctx, t, lval, |
09b42213 | 4424 | non_constant_p, overflow_p); |
4425 | break; | |
4426 | ||
4427 | case ADDR_EXPR: | |
4428 | { | |
4429 | tree oldop = TREE_OPERAND (t, 0); | |
cf72f34d | 4430 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4431 | /*lval*/true, |
b2a43197 | 4432 | non_constant_p, overflow_p); |
09b42213 | 4433 | /* Don't VERIFY_CONSTANT here. */ |
4434 | if (*non_constant_p) | |
4435 | return t; | |
1eb418cc | 4436 | gcc_checking_assert (TREE_CODE (op) != CONSTRUCTOR); |
09b42213 | 4437 | /* This function does more aggressive folding than fold itself. */ |
4438 | r = build_fold_addr_expr_with_type (op, TREE_TYPE (t)); | |
4439 | if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop) | |
4440 | return t; | |
4441 | break; | |
4442 | } | |
4443 | ||
4444 | case REALPART_EXPR: | |
4445 | case IMAGPART_EXPR: | |
6fe424c2 | 4446 | if (lval) |
4447 | { | |
4448 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4449 | non_constant_p, overflow_p); | |
4450 | if (r == error_mark_node) | |
4451 | ; | |
4452 | else if (r == TREE_OPERAND (t, 0)) | |
4453 | r = t; | |
4454 | else | |
4455 | r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), r); | |
4456 | break; | |
4457 | } | |
4458 | /* FALLTHRU */ | |
09b42213 | 4459 | case CONJ_EXPR: |
4460 | case FIX_TRUNC_EXPR: | |
4461 | case FLOAT_EXPR: | |
4462 | case NEGATE_EXPR: | |
4463 | case ABS_EXPR: | |
19b4138e | 4464 | case ABSU_EXPR: |
09b42213 | 4465 | case BIT_NOT_EXPR: |
4466 | case TRUTH_NOT_EXPR: | |
4467 | case FIXED_CONVERT_EXPR: | |
1227ba74 | 4468 | r = cxx_eval_unary_expression (ctx, t, lval, |
09b42213 | 4469 | non_constant_p, overflow_p); |
4470 | break; | |
4471 | ||
4472 | case SIZEOF_EXPR: | |
d2c63826 | 4473 | r = fold_sizeof_expr (t); |
09b42213 | 4474 | VERIFY_CONSTANT (r); |
4475 | break; | |
4476 | ||
4477 | case COMPOUND_EXPR: | |
4478 | { | |
4479 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
4480 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
4481 | introduced by build_call_a. */ | |
4482 | tree op0 = TREE_OPERAND (t, 0); | |
4483 | tree op1 = TREE_OPERAND (t, 1); | |
4484 | STRIP_NOPS (op1); | |
4485 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
4486 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
f83e6885 | 4487 | r = cxx_eval_constant_expression (ctx, op0, |
1227ba74 | 4488 | lval, non_constant_p, overflow_p, |
00f21715 | 4489 | jump_target); |
09b42213 | 4490 | else |
4491 | { | |
4492 | /* Check that the LHS is constant and then discard it. */ | |
f83e6885 | 4493 | cxx_eval_constant_expression (ctx, op0, |
c8f6aeb1 | 4494 | true, non_constant_p, overflow_p, |
00f21715 | 4495 | jump_target); |
cf03ba19 | 4496 | if (*non_constant_p) |
4497 | return t; | |
09b42213 | 4498 | op1 = TREE_OPERAND (t, 1); |
f83e6885 | 4499 | r = cxx_eval_constant_expression (ctx, op1, |
1227ba74 | 4500 | lval, non_constant_p, overflow_p, |
00f21715 | 4501 | jump_target); |
09b42213 | 4502 | } |
4503 | } | |
4504 | break; | |
4505 | ||
4506 | case POINTER_PLUS_EXPR: | |
57e83b58 | 4507 | case POINTER_DIFF_EXPR: |
09b42213 | 4508 | case PLUS_EXPR: |
4509 | case MINUS_EXPR: | |
4510 | case MULT_EXPR: | |
4511 | case TRUNC_DIV_EXPR: | |
4512 | case CEIL_DIV_EXPR: | |
4513 | case FLOOR_DIV_EXPR: | |
4514 | case ROUND_DIV_EXPR: | |
4515 | case TRUNC_MOD_EXPR: | |
4516 | case CEIL_MOD_EXPR: | |
4517 | case ROUND_MOD_EXPR: | |
4518 | case RDIV_EXPR: | |
4519 | case EXACT_DIV_EXPR: | |
4520 | case MIN_EXPR: | |
4521 | case MAX_EXPR: | |
4522 | case LSHIFT_EXPR: | |
4523 | case RSHIFT_EXPR: | |
4524 | case LROTATE_EXPR: | |
4525 | case RROTATE_EXPR: | |
4526 | case BIT_IOR_EXPR: | |
4527 | case BIT_XOR_EXPR: | |
4528 | case BIT_AND_EXPR: | |
4529 | case TRUTH_XOR_EXPR: | |
4530 | case LT_EXPR: | |
4531 | case LE_EXPR: | |
4532 | case GT_EXPR: | |
4533 | case GE_EXPR: | |
4534 | case EQ_EXPR: | |
4535 | case NE_EXPR: | |
4536 | case UNORDERED_EXPR: | |
4537 | case ORDERED_EXPR: | |
4538 | case UNLT_EXPR: | |
4539 | case UNLE_EXPR: | |
4540 | case UNGT_EXPR: | |
4541 | case UNGE_EXPR: | |
4542 | case UNEQ_EXPR: | |
4543 | case LTGT_EXPR: | |
4544 | case RANGE_EXPR: | |
4545 | case COMPLEX_EXPR: | |
1227ba74 | 4546 | r = cxx_eval_binary_expression (ctx, t, lval, |
09b42213 | 4547 | non_constant_p, overflow_p); |
4548 | break; | |
4549 | ||
4550 | /* fold can introduce non-IF versions of these; still treat them as | |
4551 | short-circuiting. */ | |
4552 | case TRUTH_AND_EXPR: | |
4553 | case TRUTH_ANDIF_EXPR: | |
cf72f34d | 4554 | r = cxx_eval_logical_expression (ctx, t, boolean_false_node, |
09b42213 | 4555 | boolean_true_node, |
1227ba74 | 4556 | lval, |
09b42213 | 4557 | non_constant_p, overflow_p); |
4558 | break; | |
4559 | ||
4560 | case TRUTH_OR_EXPR: | |
4561 | case TRUTH_ORIF_EXPR: | |
cf72f34d | 4562 | r = cxx_eval_logical_expression (ctx, t, boolean_true_node, |
09b42213 | 4563 | boolean_false_node, |
1227ba74 | 4564 | lval, |
09b42213 | 4565 | non_constant_p, overflow_p); |
4566 | break; | |
4567 | ||
4568 | case ARRAY_REF: | |
1227ba74 | 4569 | r = cxx_eval_array_reference (ctx, t, lval, |
09b42213 | 4570 | non_constant_p, overflow_p); |
4571 | break; | |
4572 | ||
4573 | case COMPONENT_REF: | |
4574 | if (is_overloaded_fn (t)) | |
4575 | { | |
4576 | /* We can only get here in checking mode via | |
4577 | build_non_dependent_expr, because any expression that | |
4578 | calls or takes the address of the function will have | |
4579 | pulled a FUNCTION_DECL out of the COMPONENT_REF. */ | |
f83e6885 | 4580 | gcc_checking_assert (ctx->quiet || errorcount); |
09b42213 | 4581 | *non_constant_p = true; |
4582 | return t; | |
4583 | } | |
1227ba74 | 4584 | r = cxx_eval_component_reference (ctx, t, lval, |
09b42213 | 4585 | non_constant_p, overflow_p); |
4586 | break; | |
4587 | ||
4588 | case BIT_FIELD_REF: | |
1227ba74 | 4589 | r = cxx_eval_bit_field_ref (ctx, t, lval, |
09b42213 | 4590 | non_constant_p, overflow_p); |
4591 | break; | |
4592 | ||
4593 | case COND_EXPR: | |
2a2770c6 | 4594 | if (jump_target && *jump_target) |
4595 | { | |
4596 | /* When jumping to a label, the label might be either in the | |
4597 | then or else blocks, so process then block first in skipping | |
4598 | mode first, and if we are still in the skipping mode at its end, | |
4599 | process the else block too. */ | |
4600 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
4601 | lval, non_constant_p, overflow_p, | |
4602 | jump_target); | |
4603 | if (*jump_target) | |
4604 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
4605 | lval, non_constant_p, overflow_p, | |
4606 | jump_target); | |
4607 | break; | |
4608 | } | |
1227ba74 | 4609 | r = cxx_eval_conditional_expression (ctx, t, lval, |
00f21715 | 4610 | non_constant_p, overflow_p, |
4611 | jump_target); | |
09b42213 | 4612 | break; |
31595caf | 4613 | case VEC_COND_EXPR: |
4614 | r = cxx_eval_vector_conditional_expression (ctx, t, non_constant_p, | |
4615 | overflow_p); | |
4616 | break; | |
09b42213 | 4617 | |
4618 | case CONSTRUCTOR: | |
1a3631bc | 4619 | if (TREE_CONSTANT (t)) |
58b0f9ce | 4620 | { |
4621 | /* Don't re-process a constant CONSTRUCTOR, but do fold it to | |
4622 | VECTOR_CST if applicable. */ | |
79e65a6b | 4623 | verify_constructor_flags (t); |
58b0f9ce | 4624 | if (TREE_CONSTANT (t)) |
4625 | return fold (t); | |
4626 | } | |
1227ba74 | 4627 | r = cxx_eval_bare_aggregate (ctx, t, lval, |
09b42213 | 4628 | non_constant_p, overflow_p); |
4629 | break; | |
4630 | ||
4631 | case VEC_INIT_EXPR: | |
4632 | /* We can get this in a defaulted constructor for a class with a | |
4633 | non-static data member of array type. Either the initializer will | |
4634 | be NULL, meaning default-initialization, or it will be an lvalue | |
4635 | or xvalue of the same type, meaning direct-initialization from the | |
4636 | corresponding member. */ | |
1227ba74 | 4637 | r = cxx_eval_vec_init (ctx, t, lval, |
09b42213 | 4638 | non_constant_p, overflow_p); |
4639 | break; | |
4640 | ||
09b42213 | 4641 | case VEC_PERM_EXPR: |
1227ba74 | 4642 | r = cxx_eval_trinary_expression (ctx, t, lval, |
09b42213 | 4643 | non_constant_p, overflow_p); |
4644 | break; | |
4645 | ||
941fafa5 | 4646 | case NOP_EXPR: |
4647 | if (REINTERPRET_CAST_P (t)) | |
4648 | { | |
4649 | if (!ctx->quiet) | |
d3a3cfb8 | 4650 | error_at (cp_expr_loc_or_loc (t, input_location), |
941fafa5 | 4651 | "a reinterpret_cast is not a constant expression"); |
4652 | *non_constant_p = true; | |
4653 | return t; | |
4654 | } | |
4655 | /* FALLTHROUGH. */ | |
09b42213 | 4656 | case CONVERT_EXPR: |
4657 | case VIEW_CONVERT_EXPR: | |
d2c63826 | 4658 | case UNARY_PLUS_EXPR: |
09b42213 | 4659 | { |
4660 | tree oldop = TREE_OPERAND (t, 0); | |
d2c63826 | 4661 | |
cf72f34d | 4662 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4663 | lval, |
b2a43197 | 4664 | non_constant_p, overflow_p); |
09b42213 | 4665 | if (*non_constant_p) |
4666 | return t; | |
f16ed232 | 4667 | tree type = TREE_TYPE (t); |
4668 | if (TREE_CODE (op) == PTRMEM_CST | |
4669 | && !TYPE_PTRMEM_P (type)) | |
4670 | op = cplus_expand_constant (op); | |
941fafa5 | 4671 | |
6a9b35ef | 4672 | if (TREE_CODE (op) == PTRMEM_CST && tcode == NOP_EXPR) |
4673 | { | |
941fafa5 | 4674 | if (!same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (op)) |
4675 | && !can_convert_qual (type, op)) | |
4676 | op = cplus_expand_constant (op); | |
4677 | return cp_fold_convert (type, op); | |
6a9b35ef | 4678 | } |
cb768824 | 4679 | |
d03fa520 | 4680 | if (INDIRECT_TYPE_P (type) && TREE_CODE (op) == INTEGER_CST) |
09b42213 | 4681 | { |
cb768824 | 4682 | if (integer_zerop (op)) |
4683 | { | |
90ad495b | 4684 | if (TYPE_REF_P (type)) |
cb768824 | 4685 | { |
4686 | if (!ctx->quiet) | |
d3a3cfb8 | 4687 | error_at (cp_expr_loc_or_loc (t, input_location), |
cb768824 | 4688 | "dereferencing a null pointer"); |
4689 | *non_constant_p = true; | |
4690 | return t; | |
4691 | } | |
90ad495b | 4692 | else if (TYPE_PTR_P (TREE_TYPE (op))) |
cb768824 | 4693 | { |
4694 | tree from = TREE_TYPE (op); | |
4695 | ||
4696 | if (!can_convert (type, from, tf_none)) | |
4697 | { | |
4698 | if (!ctx->quiet) | |
d3a3cfb8 | 4699 | error_at (cp_expr_loc_or_loc (t, input_location), |
cb768824 | 4700 | "conversion of %qT null pointer to %qT " |
4701 | "is not a constant expression", | |
4702 | from, type); | |
4703 | *non_constant_p = true; | |
4704 | return t; | |
4705 | } | |
4706 | } | |
4707 | } | |
4708 | else | |
4709 | { | |
4710 | /* This detects for example: | |
4711 | reinterpret_cast<void*>(sizeof 0) | |
4712 | */ | |
4713 | if (!ctx->quiet) | |
d3a3cfb8 | 4714 | error_at (cp_expr_loc_or_loc (t, input_location), |
cb768824 | 4715 | "%<reinterpret_cast<%T>(%E)%> is not " |
ea034e2c | 4716 | "a constant expression", |
cb768824 | 4717 | type, op); |
4718 | *non_constant_p = true; | |
4719 | return t; | |
4720 | } | |
09b42213 | 4721 | } |
941fafa5 | 4722 | |
d2c63826 | 4723 | if (op == oldop && tcode != UNARY_PLUS_EXPR) |
09b42213 | 4724 | /* We didn't fold at the top so we could check for ptr-int |
4725 | conversion. */ | |
4726 | return fold (t); | |
941fafa5 | 4727 | |
6b53d686 | 4728 | /* Handle an array's bounds having been deduced after we built |
4729 | the wrapping expression. */ | |
4730 | if (same_type_ignoring_tlq_and_bounds_p (type, TREE_TYPE (op))) | |
4731 | r = op; | |
4732 | else if (tcode == UNARY_PLUS_EXPR) | |
d2c63826 | 4733 | r = fold_convert (TREE_TYPE (t), op); |
4734 | else | |
4735 | r = fold_build1 (tcode, type, op); | |
941fafa5 | 4736 | |
09b42213 | 4737 | /* Conversion of an out-of-range value has implementation-defined |
4738 | behavior; the language considers it different from arithmetic | |
4739 | overflow, which is undefined. */ | |
4740 | if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op)) | |
4741 | TREE_OVERFLOW (r) = false; | |
4742 | } | |
4743 | break; | |
4744 | ||
4745 | case EMPTY_CLASS_EXPR: | |
4746 | /* This is good enough for a function argument that might not get | |
4747 | used, and they can't do anything with it, so just return it. */ | |
4748 | return t; | |
4749 | ||
9c96033c | 4750 | case STATEMENT_LIST: |
00f21715 | 4751 | new_ctx = *ctx; |
4752 | new_ctx.ctor = new_ctx.object = NULL_TREE; | |
f83e6885 | 4753 | return cxx_eval_statement_list (&new_ctx, t, |
00f21715 | 4754 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4755 | |
4756 | case BIND_EXPR: | |
4757 | return cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t), | |
1227ba74 | 4758 | lval, |
00f21715 | 4759 | non_constant_p, overflow_p, |
4760 | jump_target); | |
9c96033c | 4761 | |
09b42213 | 4762 | case PREINCREMENT_EXPR: |
4763 | case POSTINCREMENT_EXPR: | |
4764 | case PREDECREMENT_EXPR: | |
4765 | case POSTDECREMENT_EXPR: | |
f83e6885 | 4766 | return cxx_eval_increment_expression (ctx, t, |
1227ba74 | 4767 | lval, non_constant_p, overflow_p); |
9c96033c | 4768 | |
4769 | case LAMBDA_EXPR: | |
09b42213 | 4770 | case NEW_EXPR: |
4771 | case VEC_NEW_EXPR: | |
4772 | case DELETE_EXPR: | |
4773 | case VEC_DELETE_EXPR: | |
4774 | case THROW_EXPR: | |
09b42213 | 4775 | case MODOP_EXPR: |
4776 | /* GCC internal stuff. */ | |
4777 | case VA_ARG_EXPR: | |
4778 | case OBJ_TYPE_REF: | |
09b42213 | 4779 | case NON_DEPENDENT_EXPR: |
4780 | case BASELINK: | |
09b42213 | 4781 | case OFFSET_REF: |
f83e6885 | 4782 | if (!ctx->quiet) |
d3a3cfb8 | 4783 | error_at (cp_expr_loc_or_loc (t, input_location), |
ea034e2c | 4784 | "expression %qE is not a constant expression", t); |
09b42213 | 4785 | *non_constant_p = true; |
4786 | break; | |
4787 | ||
cf72f34d | 4788 | case PLACEHOLDER_EXPR: |
85de9604 | 4789 | /* Use of the value or address of the current object. */ |
4790 | if (tree ctor = lookup_placeholder (ctx, lval, TREE_TYPE (t))) | |
4791 | return cxx_eval_constant_expression (ctx, ctor, lval, | |
4792 | non_constant_p, overflow_p); | |
4793 | /* A placeholder without a referent. We can get here when | |
4794 | checking whether NSDMIs are noexcept, or in massage_init_elt; | |
4795 | just say it's non-constant for now. */ | |
4796 | gcc_assert (ctx->quiet); | |
4797 | *non_constant_p = true; | |
cf72f34d | 4798 | break; |
4799 | ||
cf03ba19 | 4800 | case EXIT_EXPR: |
4801 | { | |
4802 | tree cond = TREE_OPERAND (t, 0); | |
4803 | cond = cxx_eval_constant_expression (ctx, cond, /*lval*/false, | |
4804 | non_constant_p, overflow_p); | |
4805 | VERIFY_CONSTANT (cond); | |
4806 | if (integer_nonzerop (cond)) | |
4807 | *jump_target = t; | |
4808 | } | |
4809 | break; | |
4810 | ||
9c96033c | 4811 | case GOTO_EXPR: |
00f21715 | 4812 | *jump_target = TREE_OPERAND (t, 0); |
d29e4e8c | 4813 | gcc_assert (breaks (jump_target) || continues (jump_target) |
4814 | /* Allow for jumping to a cdtor_label. */ | |
4815 | || returns (jump_target)); | |
00f21715 | 4816 | break; |
4817 | ||
9c96033c | 4818 | case LOOP_EXPR: |
f83e6885 | 4819 | cxx_eval_loop_expr (ctx, t, |
00f21715 | 4820 | non_constant_p, overflow_p, jump_target); |
4821 | break; | |
4822 | ||
9c96033c | 4823 | case SWITCH_EXPR: |
f83e6885 | 4824 | cxx_eval_switch_expr (ctx, t, |
00f21715 | 4825 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4826 | break; |
4827 | ||
56c12fd4 | 4828 | case REQUIRES_EXPR: |
4829 | /* It's possible to get a requires-expression in a constant | |
4830 | expression. For example: | |
4831 | ||
4832 | template<typename T> concept bool C() { | |
4833 | return requires (T t) { t; }; | |
4834 | } | |
4835 | ||
4836 | template<typename T> requires !C<T>() void f(T); | |
4837 | ||
4838 | Normalization leaves f with the associated constraint | |
4839 | '!requires (T t) { ... }' which is not transformed into | |
4840 | a constraint. */ | |
4841 | if (!processing_template_decl) | |
4842 | return evaluate_constraint_expression (t, NULL_TREE); | |
4843 | else | |
4844 | *non_constant_p = true; | |
4845 | return t; | |
4846 | ||
24c6ee98 | 4847 | case ANNOTATE_EXPR: |
24c6ee98 | 4848 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
4849 | lval, | |
4850 | non_constant_p, overflow_p, | |
4851 | jump_target); | |
4852 | break; | |
4853 | ||
7285637a | 4854 | case USING_STMT: |
4855 | r = void_node; | |
4856 | break; | |
4857 | ||
09b42213 | 4858 | default: |
b9a3af23 | 4859 | if (STATEMENT_CODE_P (TREE_CODE (t))) |
4860 | { | |
4861 | /* This function doesn't know how to deal with pre-genericize | |
4862 | statements; this can only happen with statement-expressions, | |
4863 | so for now just fail. */ | |
4864 | if (!ctx->quiet) | |
4865 | error_at (EXPR_LOCATION (t), | |
ea034e2c | 4866 | "statement is not a constant expression"); |
b9a3af23 | 4867 | } |
4868 | else | |
4869 | internal_error ("unexpected expression %qE of kind %s", t, | |
4870 | get_tree_code_name (TREE_CODE (t))); | |
09b42213 | 4871 | *non_constant_p = true; |
4872 | break; | |
4873 | } | |
4874 | ||
4875 | if (r == error_mark_node) | |
4876 | *non_constant_p = true; | |
4877 | ||
4878 | if (*non_constant_p) | |
4879 | return t; | |
4880 | else | |
4881 | return r; | |
4882 | } | |
4883 | ||
6e1bbaae | 4884 | /* P0859: A function is needed for constant evaluation if it is a constexpr |
4885 | function that is named by an expression ([basic.def.odr]) that is | |
4886 | potentially constant evaluated. | |
4887 | ||
4888 | So we need to instantiate any constexpr functions mentioned by the | |
4889 | expression even if the definition isn't needed for evaluating the | |
4890 | expression. */ | |
4891 | ||
4892 | static tree | |
4893 | instantiate_cx_fn_r (tree *tp, int *walk_subtrees, void */*data*/) | |
4894 | { | |
4895 | if (TREE_CODE (*tp) == FUNCTION_DECL | |
4896 | && DECL_DECLARED_CONSTEXPR_P (*tp) | |
4897 | && !DECL_INITIAL (*tp) | |
eed138cf | 4898 | && !trivial_fn_p (*tp) |
6e1bbaae | 4899 | && DECL_TEMPLOID_INSTANTIATION (*tp)) |
4900 | { | |
4901 | ++function_depth; | |
4902 | instantiate_decl (*tp, /*defer_ok*/false, /*expl_inst*/false); | |
4903 | --function_depth; | |
4904 | } | |
4905 | else if (TREE_CODE (*tp) == CALL_EXPR | |
4906 | || TREE_CODE (*tp) == AGGR_INIT_EXPR) | |
4907 | { | |
4908 | if (EXPR_HAS_LOCATION (*tp)) | |
4909 | input_location = EXPR_LOCATION (*tp); | |
4910 | } | |
4911 | ||
4912 | if (!EXPR_P (*tp)) | |
4913 | *walk_subtrees = 0; | |
4914 | ||
4915 | return NULL_TREE; | |
4916 | } | |
4917 | static void | |
4918 | instantiate_constexpr_fns (tree t) | |
4919 | { | |
4920 | location_t loc = input_location; | |
4921 | cp_walk_tree_without_duplicates (&t, instantiate_cx_fn_r, NULL); | |
4922 | input_location = loc; | |
4923 | } | |
4924 | ||
18d371d3 | 4925 | /* ALLOW_NON_CONSTANT is false if T is required to be a constant expression. |
4926 | PRETEND_CONST_REQUIRED is true if T is required to be const-evaluated as | |
4927 | per P0595 even when ALLOW_NON_CONSTANT is true. */ | |
4928 | ||
09b42213 | 4929 | static tree |
cf72f34d | 4930 | cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, |
18d371d3 | 4931 | bool strict = true, |
4932 | bool pretend_const_required = false, | |
4933 | tree object = NULL_TREE) | |
09b42213 | 4934 | { |
c300fe28 | 4935 | auto_timevar time (TV_CONSTEXPR); |
4936 | ||
09b42213 | 4937 | bool non_constant_p = false; |
4938 | bool overflow_p = false; | |
cf72f34d | 4939 | hash_map<tree,tree> map; |
2631cb67 | 4940 | |
2a2770c6 | 4941 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, NULL, NULL, |
18d371d3 | 4942 | allow_non_constant, strict, |
4943 | pretend_const_required || !allow_non_constant }; | |
2631cb67 | 4944 | |
cf72f34d | 4945 | tree type = initialized_type (t); |
cf72f34d | 4946 | tree r = t; |
4947 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) | |
4948 | { | |
4949 | /* In C++14 an NSDMI can participate in aggregate initialization, | |
4950 | and can refer to the address of the object being initialized, so | |
4951 | we need to pass in the relevant VAR_DECL if we want to do the | |
4952 | evaluation in a single pass. The evaluation will dynamically | |
4953 | update ctx.values for the VAR_DECL. We use the same strategy | |
4954 | for C++11 constexpr constructors that refer to the object being | |
4955 | initialized. */ | |
4956 | ctx.ctor = build_constructor (type, NULL); | |
165d0d5b | 4957 | CONSTRUCTOR_NO_CLEARING (ctx.ctor) = true; |
9c96033c | 4958 | if (!object) |
4959 | { | |
4960 | if (TREE_CODE (t) == TARGET_EXPR) | |
4961 | object = TARGET_EXPR_SLOT (t); | |
4962 | else if (TREE_CODE (t) == AGGR_INIT_EXPR) | |
4963 | object = AGGR_INIT_EXPR_SLOT (t); | |
4964 | } | |
cf72f34d | 4965 | ctx.object = object; |
4966 | if (object) | |
4967 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
4968 | (type, TREE_TYPE (object))); | |
4969 | if (object && DECL_P (object)) | |
4970 | map.put (object, ctx.ctor); | |
4971 | if (TREE_CODE (r) == TARGET_EXPR) | |
4972 | /* Avoid creating another CONSTRUCTOR when we expand the | |
4973 | TARGET_EXPR. */ | |
4974 | r = TARGET_EXPR_INITIAL (r); | |
4975 | } | |
4976 | ||
6e1bbaae | 4977 | instantiate_constexpr_fns (r); |
f83e6885 | 4978 | r = cxx_eval_constant_expression (&ctx, r, |
b2a43197 | 4979 | false, &non_constant_p, &overflow_p); |
09b42213 | 4980 | |
4981 | verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); | |
4982 | ||
bbcc9042 | 4983 | /* Mutable logic is a bit tricky: we want to allow initialization of |
4984 | constexpr variables with mutable members, but we can't copy those | |
4985 | members to another constexpr variable. */ | |
4986 | if (TREE_CODE (r) == CONSTRUCTOR | |
4987 | && CONSTRUCTOR_MUTABLE_POISON (r)) | |
09b42213 | 4988 | { |
09b42213 | 4989 | if (!allow_non_constant) |
bbcc9042 | 4990 | error ("%qE is not a constant expression because it refers to " |
4991 | "mutable subobjects of %qT", t, type); | |
09b42213 | 4992 | non_constant_p = true; |
4993 | } | |
4994 | ||
c6d97004 | 4995 | if (TREE_CODE (r) == CONSTRUCTOR |
165d0d5b | 4996 | && CONSTRUCTOR_NO_CLEARING (r)) |
c6d97004 | 4997 | { |
4998 | if (!allow_non_constant) | |
4999 | error ("%qE is not a constant expression because it refers to " | |
5000 | "an incompletely initialized variable", t); | |
5001 | TREE_CONSTANT (r) = false; | |
5002 | non_constant_p = true; | |
5003 | } | |
5004 | ||
09b42213 | 5005 | /* Technically we should check this for all subexpressions, but that |
5006 | runs into problems with our internal representation of pointer | |
5007 | subtraction and the 5.19 rules are still in flux. */ | |
5008 | if (CONVERT_EXPR_CODE_P (TREE_CODE (r)) | |
5009 | && ARITHMETIC_TYPE_P (TREE_TYPE (r)) | |
5010 | && TREE_CODE (TREE_OPERAND (r, 0)) == ADDR_EXPR) | |
5011 | { | |
5012 | if (!allow_non_constant) | |
5013 | error ("conversion from pointer type %qT " | |
ea034e2c | 5014 | "to arithmetic type %qT in a constant expression", |
09b42213 | 5015 | TREE_TYPE (TREE_OPERAND (r, 0)), TREE_TYPE (r)); |
5016 | non_constant_p = true; | |
5017 | } | |
5018 | ||
5019 | if (!non_constant_p && overflow_p) | |
5020 | non_constant_p = true; | |
5021 | ||
c6c0523b | 5022 | /* Unshare the result unless it's a CONSTRUCTOR in which case it's already |
5023 | unshared. */ | |
5024 | bool should_unshare = true; | |
5025 | if (r == t || TREE_CODE (r) == CONSTRUCTOR) | |
5026 | should_unshare = false; | |
5027 | ||
09b42213 | 5028 | if (non_constant_p && !allow_non_constant) |
5029 | return error_mark_node; | |
5030 | else if (non_constant_p && TREE_CONSTANT (r)) | |
5031 | { | |
18d371d3 | 5032 | /* If __builtin_is_constant_evaluated () was evaluated to true |
5033 | and the result is not a valid constant expression, we need to | |
5034 | punt. */ | |
5035 | if (pretend_const_required) | |
5036 | return cxx_eval_outermost_constant_expr (t, true, strict, | |
5037 | false, object); | |
1d29f4ea | 5038 | /* This isn't actually constant, so unset TREE_CONSTANT. |
5039 | Don't clear TREE_CONSTANT on ADDR_EXPR, as the middle-end requires | |
5040 | it to be set if it is invariant address, even when it is not | |
5041 | a valid C++ constant expression. Wrap it with a NOP_EXPR | |
5042 | instead. */ | |
5043 | if (EXPR_P (r) && TREE_CODE (r) != ADDR_EXPR) | |
09b42213 | 5044 | r = copy_node (r); |
5045 | else if (TREE_CODE (r) == CONSTRUCTOR) | |
5046 | r = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (r), r); | |
5047 | else | |
5048 | r = build_nop (TREE_TYPE (r), r); | |
5049 | TREE_CONSTANT (r) = false; | |
5050 | } | |
5051 | else if (non_constant_p || r == t) | |
5052 | return t; | |
5053 | ||
c6c0523b | 5054 | if (should_unshare) |
5055 | r = unshare_expr (r); | |
5056 | ||
09b42213 | 5057 | if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r))) |
5058 | { | |
5059 | if (TREE_CODE (t) == TARGET_EXPR | |
5060 | && TARGET_EXPR_INITIAL (t) == r) | |
5061 | return t; | |
5062 | else | |
5063 | { | |
5064 | r = get_target_expr (r); | |
5065 | TREE_CONSTANT (r) = true; | |
5066 | return r; | |
5067 | } | |
5068 | } | |
5069 | else | |
5070 | return r; | |
5071 | } | |
5072 | ||
5073 | /* Returns true if T is a valid subexpression of a constant expression, | |
5074 | even if it isn't itself a constant expression. */ | |
5075 | ||
5076 | bool | |
5077 | is_sub_constant_expr (tree t) | |
5078 | { | |
5079 | bool non_constant_p = false; | |
5080 | bool overflow_p = false; | |
cf72f34d | 5081 | hash_map <tree, tree> map; |
2631cb67 | 5082 | |
18d371d3 | 5083 | constexpr_ctx ctx |
5084 | = { NULL, &map, NULL, NULL, NULL, NULL, true, true, false }; | |
2631cb67 | 5085 | |
6e1bbaae | 5086 | instantiate_constexpr_fns (t); |
f83e6885 | 5087 | cxx_eval_constant_expression (&ctx, t, false, &non_constant_p, |
b2a43197 | 5088 | &overflow_p); |
09b42213 | 5089 | return !non_constant_p && !overflow_p; |
5090 | } | |
5091 | ||
5092 | /* If T represents a constant expression returns its reduced value. | |
5093 | Otherwise return error_mark_node. If T is dependent, then | |
5094 | return NULL. */ | |
5095 | ||
5096 | tree | |
cf72f34d | 5097 | cxx_constant_value (tree t, tree decl) |
09b42213 | 5098 | { |
18d371d3 | 5099 | return cxx_eval_outermost_constant_expr (t, false, true, true, decl); |
09b42213 | 5100 | } |
5101 | ||
d2c63826 | 5102 | /* Helper routine for fold_simple function. Either return simplified |
5103 | expression T, otherwise NULL_TREE. | |
5104 | In contrast to cp_fully_fold, and to maybe_constant_value, we try to fold | |
5105 | even if we are within template-declaration. So be careful on call, as in | |
5106 | such case types can be undefined. */ | |
5107 | ||
5108 | static tree | |
5109 | fold_simple_1 (tree t) | |
5110 | { | |
5111 | tree op1; | |
5112 | enum tree_code code = TREE_CODE (t); | |
5113 | ||
5114 | switch (code) | |
5115 | { | |
5116 | case INTEGER_CST: | |
5117 | case REAL_CST: | |
5118 | case VECTOR_CST: | |
5119 | case FIXED_CST: | |
5120 | case COMPLEX_CST: | |
5121 | return t; | |
5122 | ||
5123 | case SIZEOF_EXPR: | |
5124 | return fold_sizeof_expr (t); | |
5125 | ||
5126 | case ABS_EXPR: | |
19b4138e | 5127 | case ABSU_EXPR: |
d2c63826 | 5128 | case CONJ_EXPR: |
5129 | case REALPART_EXPR: | |
5130 | case IMAGPART_EXPR: | |
5131 | case NEGATE_EXPR: | |
5132 | case BIT_NOT_EXPR: | |
5133 | case TRUTH_NOT_EXPR: | |
5134 | case NOP_EXPR: | |
5135 | case VIEW_CONVERT_EXPR: | |
5136 | case CONVERT_EXPR: | |
5137 | case FLOAT_EXPR: | |
5138 | case FIX_TRUNC_EXPR: | |
5139 | case FIXED_CONVERT_EXPR: | |
5140 | case ADDR_SPACE_CONVERT_EXPR: | |
5141 | ||
5142 | op1 = TREE_OPERAND (t, 0); | |
5143 | ||
5144 | t = const_unop (code, TREE_TYPE (t), op1); | |
5145 | if (!t) | |
5146 | return NULL_TREE; | |
5147 | ||
5148 | if (CONVERT_EXPR_CODE_P (code) | |
5149 | && TREE_OVERFLOW_P (t) && !TREE_OVERFLOW_P (op1)) | |
5150 | TREE_OVERFLOW (t) = false; | |
5151 | return t; | |
5152 | ||
5153 | default: | |
5154 | return NULL_TREE; | |
5155 | } | |
5156 | } | |
5157 | ||
5158 | /* If T is a simple constant expression, returns its simplified value. | |
6fe5fea9 | 5159 | Otherwise returns T. In contrast to maybe_constant_value we |
d2c63826 | 5160 | simplify only few operations on constant-expressions, and we don't |
5161 | try to simplify constexpressions. */ | |
5162 | ||
5163 | tree | |
5164 | fold_simple (tree t) | |
5165 | { | |
d2c63826 | 5166 | if (processing_template_decl) |
5167 | return t; | |
5168 | ||
6fe5fea9 | 5169 | tree r = fold_simple_1 (t); |
5170 | if (r) | |
5171 | return r; | |
d2c63826 | 5172 | |
6fe5fea9 | 5173 | return t; |
d2c63826 | 5174 | } |
5175 | ||
09b42213 | 5176 | /* If T is a constant expression, returns its reduced value. |
5177 | Otherwise, if T does not have TREE_CONSTANT set, returns T. | |
5178 | Otherwise, returns a version of T without TREE_CONSTANT. */ | |
5179 | ||
b601ad30 | 5180 | static GTY((deletable)) hash_map<tree, tree> *cv_cache; |
5181 | ||
5182 | tree | |
5183 | maybe_constant_value (tree t, tree decl) | |
09b42213 | 5184 | { |
5185 | tree r; | |
5186 | ||
7e1f8be4 | 5187 | if (!is_nondependent_constant_expression (t)) |
09b42213 | 5188 | { |
5189 | if (TREE_OVERFLOW_P (t)) | |
5190 | { | |
5191 | t = build_nop (TREE_TYPE (t), t); | |
5192 | TREE_CONSTANT (t) = false; | |
5193 | } | |
5194 | return t; | |
5195 | } | |
b601ad30 | 5196 | else if (CONSTANT_CLASS_P (t)) |
5197 | /* No caching or evaluation needed. */ | |
5198 | return t; | |
5199 | ||
5200 | if (cv_cache == NULL) | |
5201 | cv_cache = hash_map<tree, tree>::create_ggc (101); | |
5202 | if (tree *cached = cv_cache->get (t)) | |
5203 | return *cached; | |
09b42213 | 5204 | |
18d371d3 | 5205 | r = cxx_eval_outermost_constant_expr (t, true, true, false, decl); |
5e8689fb | 5206 | gcc_checking_assert (r == t |
5207 | || CONVERT_EXPR_P (t) | |
5208 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
5209 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
5210 | || !cp_tree_equal (r, t)); | |
b601ad30 | 5211 | cv_cache->put (t, r); |
09b42213 | 5212 | return r; |
5213 | } | |
5214 | ||
2a655a4c | 5215 | /* Dispose of the whole CV_CACHE. */ |
5216 | ||
5217 | static void | |
5218 | clear_cv_cache (void) | |
5219 | { | |
5220 | if (cv_cache != NULL) | |
5221 | cv_cache->empty (); | |
5222 | } | |
5223 | ||
f553d9f8 | 5224 | /* Dispose of the whole CV_CACHE and FOLD_CACHE. */ |
a0c919f7 | 5225 | |
5226 | void | |
f553d9f8 | 5227 | clear_cv_and_fold_caches (void) |
a0c919f7 | 5228 | { |
2a655a4c | 5229 | clear_cv_cache (); |
f553d9f8 | 5230 | clear_fold_cache (); |
a0c919f7 | 5231 | } |
5232 | ||
21131a05 | 5233 | /* Like maybe_constant_value but first fully instantiate the argument. |
5234 | ||
5235 | Note: this is equivalent to instantiate_non_dependent_expr_sfinae | |
006b503a | 5236 | (t, complain) followed by maybe_constant_value but is more efficient, |
5237 | because it calls instantiation_dependent_expression_p and | |
5238 | potential_constant_expression at most once. | |
5239 | ||
5240 | Callers should generally pass their active complain, or if they are in a | |
5241 | non-template, diagnosing context, they can use the default of | |
5242 | tf_warning_or_error. Callers that might be within a template context, don't | |
5243 | have a complain parameter, and aren't going to remember the result for long | |
5244 | (e.g. null_ptr_cst_p), can pass tf_none and deal with error_mark_node | |
5245 | appropriately. */ | |
21131a05 | 5246 | |
5247 | tree | |
006b503a | 5248 | fold_non_dependent_expr (tree t, |
5249 | tsubst_flags_t complain /* = tf_warning_or_error */) | |
21131a05 | 5250 | { |
5251 | if (t == NULL_TREE) | |
5252 | return NULL_TREE; | |
5253 | ||
5254 | /* If we're in a template, but T isn't value dependent, simplify | |
5255 | it. We're supposed to treat: | |
5256 | ||
5257 | template <typename T> void f(T[1 + 1]); | |
5258 | template <typename T> void f(T[2]); | |
5259 | ||
5260 | as two declarations of the same function, for example. */ | |
5261 | if (processing_template_decl) | |
5262 | { | |
7e1f8be4 | 5263 | if (is_nondependent_constant_expression (t)) |
21131a05 | 5264 | { |
c8a9f04c | 5265 | processing_template_decl_sentinel s; |
006b503a | 5266 | t = instantiate_non_dependent_expr_internal (t, complain); |
21131a05 | 5267 | |
5268 | if (type_unknown_p (t) | |
5269 | || BRACE_ENCLOSED_INITIALIZER_P (t)) | |
5270 | { | |
5271 | if (TREE_OVERFLOW_P (t)) | |
5272 | { | |
5273 | t = build_nop (TREE_TYPE (t), t); | |
5274 | TREE_CONSTANT (t) = false; | |
5275 | } | |
5276 | return t; | |
5277 | } | |
5278 | ||
18d371d3 | 5279 | tree r = cxx_eval_outermost_constant_expr (t, true, true, false, |
5280 | NULL_TREE); | |
21131a05 | 5281 | /* cp_tree_equal looks through NOPs, so allow them. */ |
5e8689fb | 5282 | gcc_checking_assert (r == t |
5283 | || CONVERT_EXPR_P (t) | |
5284 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
5285 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
5286 | || !cp_tree_equal (r, t)); | |
21131a05 | 5287 | return r; |
5288 | } | |
5289 | else if (TREE_OVERFLOW_P (t)) | |
5290 | { | |
5291 | t = build_nop (TREE_TYPE (t), t); | |
5292 | TREE_CONSTANT (t) = false; | |
5293 | } | |
5294 | return t; | |
5295 | } | |
5296 | ||
5297 | return maybe_constant_value (t); | |
5298 | } | |
5299 | ||
09b42213 | 5300 | /* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather |
18d371d3 | 5301 | than wrapped in a TARGET_EXPR. |
5302 | ALLOW_NON_CONSTANT is false if T is required to be a constant expression. | |
5303 | PRETEND_CONST_REQUIRED is true if T is required to be const-evaluated as | |
5304 | per P0595 even when ALLOW_NON_CONSTANT is true. */ | |
09b42213 | 5305 | |
0c703e14 | 5306 | static tree |
18d371d3 | 5307 | maybe_constant_init_1 (tree t, tree decl, bool allow_non_constant, |
5308 | bool pretend_const_required) | |
09b42213 | 5309 | { |
d2c63826 | 5310 | if (!t) |
5311 | return t; | |
09b42213 | 5312 | if (TREE_CODE (t) == EXPR_STMT) |
5313 | t = TREE_OPERAND (t, 0); | |
5314 | if (TREE_CODE (t) == CONVERT_EXPR | |
5315 | && VOID_TYPE_P (TREE_TYPE (t))) | |
5316 | t = TREE_OPERAND (t, 0); | |
9c96033c | 5317 | if (TREE_CODE (t) == INIT_EXPR) |
5318 | t = TREE_OPERAND (t, 1); | |
c6d97004 | 5319 | if (TREE_CODE (t) == TARGET_EXPR) |
5320 | t = TARGET_EXPR_INITIAL (t); | |
7e1f8be4 | 5321 | if (!is_nondependent_static_init_expression (t)) |
2055d27a | 5322 | /* Don't try to evaluate it. */; |
0c703e14 | 5323 | else if (CONSTANT_CLASS_P (t) && allow_non_constant) |
b601ad30 | 5324 | /* No evaluation needed. */; |
2055d27a | 5325 | else |
18d371d3 | 5326 | t = cxx_eval_outermost_constant_expr (t, allow_non_constant, |
5327 | !allow_non_constant, | |
5328 | pretend_const_required, decl); | |
09b42213 | 5329 | if (TREE_CODE (t) == TARGET_EXPR) |
5330 | { | |
5331 | tree init = TARGET_EXPR_INITIAL (t); | |
5332 | if (TREE_CODE (init) == CONSTRUCTOR) | |
5333 | t = init; | |
5334 | } | |
5335 | return t; | |
5336 | } | |
5337 | ||
0c703e14 | 5338 | /* Wrapper for maybe_constant_init_1 which permits non constants. */ |
5339 | ||
5340 | tree | |
18d371d3 | 5341 | maybe_constant_init (tree t, tree decl, bool pretend_const_required) |
0c703e14 | 5342 | { |
18d371d3 | 5343 | return maybe_constant_init_1 (t, decl, true, pretend_const_required); |
0c703e14 | 5344 | } |
5345 | ||
5346 | /* Wrapper for maybe_constant_init_1 which does not permit non constants. */ | |
5347 | ||
5348 | tree | |
5349 | cxx_constant_init (tree t, tree decl) | |
5350 | { | |
18d371d3 | 5351 | return maybe_constant_init_1 (t, decl, false, true); |
0c703e14 | 5352 | } |
5353 | ||
09b42213 | 5354 | #if 0 |
5355 | /* FIXME see ADDR_EXPR section in potential_constant_expression_1. */ | |
5356 | /* Return true if the object referred to by REF has automatic or thread | |
5357 | local storage. */ | |
5358 | ||
5359 | enum { ck_ok, ck_bad, ck_unknown }; | |
5360 | static int | |
5361 | check_automatic_or_tls (tree ref) | |
5362 | { | |
3754d046 | 5363 | machine_mode mode; |
81bc0f0f | 5364 | poly_int64 bitsize, bitpos; |
09b42213 | 5365 | tree offset; |
5366 | int volatilep = 0, unsignedp = 0; | |
5367 | tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset, | |
5368 | &mode, &unsignedp, &volatilep, false); | |
5369 | duration_kind dk; | |
5370 | ||
5371 | /* If there isn't a decl in the middle, we don't know the linkage here, | |
5372 | and this isn't a constant expression anyway. */ | |
5373 | if (!DECL_P (decl)) | |
5374 | return ck_unknown; | |
5375 | dk = decl_storage_duration (decl); | |
5376 | return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok; | |
5377 | } | |
5378 | #endif | |
5379 | ||
5380 | /* Return true if T denotes a potentially constant expression. Issue | |
5381 | diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true, | |
7e1f8be4 | 5382 | an lvalue-rvalue conversion is implied. If NOW is true, we want to |
5383 | consider the expression in the current context, independent of constexpr | |
5384 | substitution. | |
09b42213 | 5385 | |
5386 | C++0x [expr.const] used to say | |
5387 | ||
5388 | 6 An expression is a potential constant expression if it is | |
5389 | a constant expression where all occurrences of function | |
5390 | parameters are replaced by arbitrary constant expressions | |
5391 | of the appropriate type. | |
5392 | ||
5393 | 2 A conditional expression is a constant expression unless it | |
5394 | involves one of the following as a potentially evaluated | |
5395 | subexpression (3.2), but subexpressions of logical AND (5.14), | |
5396 | logical OR (5.15), and conditional (5.16) operations that are | |
5397 | not evaluated are not considered. */ | |
5398 | ||
5399 | static bool | |
7e1f8be4 | 5400 | potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, |
2055d27a | 5401 | tsubst_flags_t flags) |
09b42213 | 5402 | { |
7e1f8be4 | 5403 | #define RECUR(T,RV) \ |
5404 | potential_constant_expression_1 ((T), (RV), strict, now, flags) | |
5405 | ||
09b42213 | 5406 | enum { any = false, rval = true }; |
5407 | int i; | |
5408 | tree tmp; | |
5409 | ||
5410 | if (t == error_mark_node) | |
5411 | return false; | |
5412 | if (t == NULL_TREE) | |
5413 | return true; | |
d3a3cfb8 | 5414 | location_t loc = cp_expr_loc_or_loc (t, input_location); |
eade0940 | 5415 | if (TREE_THIS_VOLATILE (t) && !DECL_P (t)) |
09b42213 | 5416 | { |
5417 | if (flags & tf_error) | |
d6a08f5c | 5418 | error_at (loc, "expression %qE has side-effects", t); |
09b42213 | 5419 | return false; |
5420 | } | |
5421 | if (CONSTANT_CLASS_P (t)) | |
5422 | return true; | |
c7282bf2 | 5423 | if (CODE_CONTAINS_STRUCT (TREE_CODE (t), TS_TYPED) |
5424 | && TREE_TYPE (t) == error_mark_node) | |
5425 | return false; | |
09b42213 | 5426 | |
5427 | switch (TREE_CODE (t)) | |
5428 | { | |
5429 | case FUNCTION_DECL: | |
5430 | case BASELINK: | |
5431 | case TEMPLATE_DECL: | |
5432 | case OVERLOAD: | |
5433 | case TEMPLATE_ID_EXPR: | |
5434 | case LABEL_DECL: | |
5435 | case LABEL_EXPR: | |
9c96033c | 5436 | case CASE_LABEL_EXPR: |
09b42213 | 5437 | case CONST_DECL: |
5438 | case SIZEOF_EXPR: | |
5439 | case ALIGNOF_EXPR: | |
5440 | case OFFSETOF_EXPR: | |
5441 | case NOEXCEPT_EXPR: | |
5442 | case TEMPLATE_PARM_INDEX: | |
5443 | case TRAIT_EXPR: | |
5444 | case IDENTIFIER_NODE: | |
5445 | case USERDEF_LITERAL: | |
5446 | /* We can see a FIELD_DECL in a pointer-to-member expression. */ | |
5447 | case FIELD_DECL: | |
d2c63826 | 5448 | case RESULT_DECL: |
09b42213 | 5449 | case USING_DECL: |
9c96033c | 5450 | case USING_STMT: |
cf72f34d | 5451 | case PLACEHOLDER_EXPR: |
9c96033c | 5452 | case BREAK_STMT: |
5453 | case CONTINUE_STMT: | |
56c12fd4 | 5454 | case REQUIRES_EXPR: |
33603066 | 5455 | case STATIC_ASSERT: |
90567983 | 5456 | case DEBUG_BEGIN_STMT: |
09b42213 | 5457 | return true; |
5458 | ||
7e1f8be4 | 5459 | case PARM_DECL: |
5460 | if (now) | |
5461 | { | |
5462 | if (flags & tf_error) | |
5463 | error ("%qE is not a constant expression", t); | |
5464 | return false; | |
5465 | } | |
5466 | return true; | |
5467 | ||
09b42213 | 5468 | case AGGR_INIT_EXPR: |
5469 | case CALL_EXPR: | |
5470 | /* -- an invocation of a function other than a constexpr function | |
5471 | or a constexpr constructor. */ | |
5472 | { | |
5473 | tree fun = get_function_named_in_call (t); | |
5474 | const int nargs = call_expr_nargs (t); | |
5475 | i = 0; | |
5476 | ||
9c96033c | 5477 | if (fun == NULL_TREE) |
5478 | { | |
732905bb | 5479 | /* Reset to allow the function to continue past the end |
5480 | of the block below. Otherwise return early. */ | |
5481 | bool bail = true; | |
5482 | ||
32cf7025 | 5483 | if (TREE_CODE (t) == CALL_EXPR |
5484 | && CALL_EXPR_FN (t) == NULL_TREE) | |
5485 | switch (CALL_EXPR_IFN (t)) | |
5486 | { | |
5487 | /* These should be ignored, they are optimized away from | |
5488 | constexpr functions. */ | |
5489 | case IFN_UBSAN_NULL: | |
5490 | case IFN_UBSAN_BOUNDS: | |
5491 | case IFN_UBSAN_VPTR: | |
3c77f69c | 5492 | case IFN_FALLTHROUGH: |
32cf7025 | 5493 | return true; |
732905bb | 5494 | |
5495 | case IFN_ADD_OVERFLOW: | |
5496 | case IFN_SUB_OVERFLOW: | |
5497 | case IFN_MUL_OVERFLOW: | |
6e1b2ffb | 5498 | case IFN_LAUNDER: |
732905bb | 5499 | bail = false; |
5500 | ||
32cf7025 | 5501 | default: |
5502 | break; | |
5503 | } | |
732905bb | 5504 | |
5505 | if (bail) | |
5506 | { | |
5507 | /* fold_call_expr can't do anything with IFN calls. */ | |
5508 | if (flags & tf_error) | |
d6a08f5c | 5509 | error_at (loc, "call to internal function %qE", t); |
732905bb | 5510 | return false; |
5511 | } | |
9c96033c | 5512 | } |
732905bb | 5513 | |
5514 | if (fun && is_overloaded_fn (fun)) | |
09b42213 | 5515 | { |
5516 | if (TREE_CODE (fun) == FUNCTION_DECL) | |
5517 | { | |
5518 | if (builtin_valid_in_constant_expr_p (fun)) | |
5519 | return true; | |
5520 | if (!DECL_DECLARED_CONSTEXPR_P (fun) | |
5521 | /* Allow any built-in function; if the expansion | |
5522 | isn't constant, we'll deal with that then. */ | |
a0e9bfbb | 5523 | && !fndecl_built_in_p (fun)) |
09b42213 | 5524 | { |
5525 | if (flags & tf_error) | |
5526 | { | |
5967b28b | 5527 | error_at (loc, "call to non-%<constexpr%> function %qD", |
d6a08f5c | 5528 | fun); |
09b42213 | 5529 | explain_invalid_constexpr_fn (fun); |
5530 | } | |
5531 | return false; | |
5532 | } | |
5533 | /* A call to a non-static member function takes the address | |
5534 | of the object as the first argument. But in a constant | |
5535 | expression the address will be folded away, so look | |
5536 | through it now. */ | |
5537 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
5538 | && !DECL_CONSTRUCTOR_P (fun)) | |
5539 | { | |
5540 | tree x = get_nth_callarg (t, 0); | |
5541 | if (is_this_parameter (x)) | |
cf72f34d | 5542 | return true; |
7e1f8be4 | 5543 | /* Don't require an immediately constant value, as |
5544 | constexpr substitution might not use the value. */ | |
5545 | bool sub_now = false; | |
5546 | if (!potential_constant_expression_1 (x, rval, strict, | |
5547 | sub_now, flags)) | |
09b42213 | 5548 | return false; |
5549 | i = 1; | |
5550 | } | |
5551 | } | |
5552 | else | |
5553 | { | |
2055d27a | 5554 | if (!RECUR (fun, true)) |
09b42213 | 5555 | return false; |
5556 | fun = get_first_fn (fun); | |
5557 | } | |
5558 | /* Skip initial arguments to base constructors. */ | |
5559 | if (DECL_BASE_CONSTRUCTOR_P (fun)) | |
5560 | i = num_artificial_parms_for (fun); | |
5561 | fun = DECL_ORIGIN (fun); | |
5562 | } | |
732905bb | 5563 | else if (fun) |
09b42213 | 5564 | { |
2055d27a | 5565 | if (RECUR (fun, rval)) |
09b42213 | 5566 | /* Might end up being a constant function pointer. */; |
5567 | else | |
5568 | return false; | |
5569 | } | |
5570 | for (; i < nargs; ++i) | |
5571 | { | |
5572 | tree x = get_nth_callarg (t, i); | |
b2742b58 | 5573 | /* In a template, reference arguments haven't been converted to |
5574 | REFERENCE_TYPE and we might not even know if the parameter | |
5575 | is a reference, so accept lvalue constants too. */ | |
5576 | bool rv = processing_template_decl ? any : rval; | |
7e1f8be4 | 5577 | /* Don't require an immediately constant value, as constexpr |
5578 | substitution might not use the value of the argument. */ | |
5579 | bool sub_now = false; | |
5580 | if (!potential_constant_expression_1 (x, rv, strict, | |
5581 | sub_now, flags)) | |
09b42213 | 5582 | return false; |
5583 | } | |
5584 | return true; | |
5585 | } | |
5586 | ||
5587 | case NON_LVALUE_EXPR: | |
5588 | /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to | |
5589 | -- an lvalue of integral type that refers to a non-volatile | |
5590 | const variable or static data member initialized with | |
5591 | constant expressions, or | |
5592 | ||
5593 | -- an lvalue of literal type that refers to non-volatile | |
5594 | object defined with constexpr, or that refers to a | |
5595 | sub-object of such an object; */ | |
2055d27a | 5596 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 5597 | |
5598 | case VAR_DECL: | |
9c8aeb66 | 5599 | if (DECL_HAS_VALUE_EXPR_P (t)) |
297de7bc | 5600 | { |
d0e2b7e7 | 5601 | if (now && is_normal_capture_proxy (t)) |
297de7bc | 5602 | { |
5603 | /* -- in a lambda-expression, a reference to this or to a | |
5604 | variable with automatic storage duration defined outside that | |
5605 | lambda-expression, where the reference would be an | |
5606 | odr-use. */ | |
5607 | if (flags & tf_error) | |
5608 | { | |
5609 | tree cap = DECL_CAPTURED_VARIABLE (t); | |
5610 | error ("lambda capture of %qE is not a constant expression", | |
5611 | cap); | |
5612 | if (!want_rval && decl_constant_var_p (cap)) | |
5613 | inform (input_location, "because it is used as a glvalue"); | |
5614 | } | |
5615 | return false; | |
5616 | } | |
5617 | return RECUR (DECL_VALUE_EXPR (t), rval); | |
5618 | } | |
2055d27a | 5619 | if (want_rval |
33603066 | 5620 | && !var_in_maybe_constexpr_fn (t) |
c7282bf2 | 5621 | && !type_dependent_expression_p (t) |
8d6486e1 | 5622 | && !decl_maybe_constant_var_p (t) |
2055d27a | 5623 | && (strict |
5624 | || !CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (t)) | |
8d6486e1 | 5625 | || (DECL_INITIAL (t) |
5626 | && !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (t))) | |
c7282bf2 | 5627 | && COMPLETE_TYPE_P (TREE_TYPE (t)) |
5628 | && !is_really_empty_class (TREE_TYPE (t))) | |
09b42213 | 5629 | { |
5630 | if (flags & tf_error) | |
5631 | non_const_var_error (t); | |
5632 | return false; | |
5633 | } | |
5634 | return true; | |
5635 | ||
5636 | case NOP_EXPR: | |
5637 | case CONVERT_EXPR: | |
5638 | case VIEW_CONVERT_EXPR: | |
5639 | /* -- a reinterpret_cast. FIXME not implemented, and this rule | |
5640 | may change to something more specific to type-punning (DR 1312). */ | |
5641 | { | |
5642 | tree from = TREE_OPERAND (t, 0); | |
d03fa520 | 5643 | if (INDIRECT_TYPE_P (TREE_TYPE (t)) |
09b42213 | 5644 | && TREE_CODE (from) == INTEGER_CST |
5645 | && !integer_zerop (from)) | |
5646 | { | |
5647 | if (flags & tf_error) | |
d6a08f5c | 5648 | error_at (loc, "reinterpret_cast from integer to pointer"); |
09b42213 | 5649 | return false; |
5650 | } | |
2055d27a | 5651 | return (RECUR (from, TREE_CODE (t) != VIEW_CONVERT_EXPR)); |
09b42213 | 5652 | } |
5653 | ||
cd45162d | 5654 | case ADDRESSOF_EXPR: |
5655 | /* This is like ADDR_EXPR, except it won't form pointer-to-member. */ | |
5656 | t = TREE_OPERAND (t, 0); | |
5657 | goto handle_addr_expr; | |
5658 | ||
09b42213 | 5659 | case ADDR_EXPR: |
5660 | /* -- a unary operator & that is applied to an lvalue that | |
5661 | designates an object with thread or automatic storage | |
5662 | duration; */ | |
5663 | t = TREE_OPERAND (t, 0); | |
5664 | ||
5665 | if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t)) | |
5666 | /* A pointer-to-member constant. */ | |
5667 | return true; | |
5668 | ||
cd45162d | 5669 | handle_addr_expr: |
09b42213 | 5670 | #if 0 |
5671 | /* FIXME adjust when issue 1197 is fully resolved. For now don't do | |
5672 | any checking here, as we might dereference the pointer later. If | |
5673 | we remove this code, also remove check_automatic_or_tls. */ | |
5674 | i = check_automatic_or_tls (t); | |
5675 | if (i == ck_ok) | |
5676 | return true; | |
5677 | if (i == ck_bad) | |
5678 | { | |
5679 | if (flags & tf_error) | |
5680 | error ("address-of an object %qE with thread local or " | |
5681 | "automatic storage is not a constant expression", t); | |
5682 | return false; | |
5683 | } | |
5684 | #endif | |
2055d27a | 5685 | return RECUR (t, any); |
09b42213 | 5686 | |
20b34a56 | 5687 | case REALPART_EXPR: |
5688 | case IMAGPART_EXPR: | |
09b42213 | 5689 | case COMPONENT_REF: |
5690 | case BIT_FIELD_REF: | |
5691 | case ARROW_EXPR: | |
5692 | case OFFSET_REF: | |
5693 | /* -- a class member access unless its postfix-expression is | |
5694 | of literal type or of pointer to literal type. */ | |
5695 | /* This test would be redundant, as it follows from the | |
5696 | postfix-expression being a potential constant expression. */ | |
eade0940 | 5697 | if (type_unknown_p (t)) |
5698 | return true; | |
2055d27a | 5699 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5700 | |
5701 | case EXPR_PACK_EXPANSION: | |
2055d27a | 5702 | return RECUR (PACK_EXPANSION_PATTERN (t), want_rval); |
09b42213 | 5703 | |
5704 | case INDIRECT_REF: | |
5705 | { | |
5706 | tree x = TREE_OPERAND (t, 0); | |
5707 | STRIP_NOPS (x); | |
997bbf70 | 5708 | if (is_this_parameter (x) && !is_capture_proxy (x)) |
09b42213 | 5709 | { |
b7e4a558 | 5710 | if (!var_in_maybe_constexpr_fn (x)) |
09b42213 | 5711 | { |
5712 | if (flags & tf_error) | |
d6a08f5c | 5713 | error_at (loc, "use of %<this%> in a constant expression"); |
09b42213 | 5714 | return false; |
5715 | } | |
09b42213 | 5716 | return true; |
5717 | } | |
2055d27a | 5718 | return RECUR (x, rval); |
09b42213 | 5719 | } |
5720 | ||
9c96033c | 5721 | case STATEMENT_LIST: |
5722 | { | |
5723 | tree_stmt_iterator i; | |
5724 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
5725 | { | |
2055d27a | 5726 | if (!RECUR (tsi_stmt (i), any)) |
9c96033c | 5727 | return false; |
5728 | } | |
5729 | return true; | |
5730 | } | |
5731 | break; | |
5732 | ||
5733 | case MODIFY_EXPR: | |
5734 | if (cxx_dialect < cxx14) | |
5735 | goto fail; | |
2055d27a | 5736 | if (!RECUR (TREE_OPERAND (t, 0), any)) |
9c96033c | 5737 | return false; |
2055d27a | 5738 | if (!RECUR (TREE_OPERAND (t, 1), rval)) |
9c96033c | 5739 | return false; |
5740 | return true; | |
5741 | ||
5742 | case MODOP_EXPR: | |
5743 | if (cxx_dialect < cxx14) | |
5744 | goto fail; | |
2055d27a | 5745 | if (!RECUR (TREE_OPERAND (t, 0), rval)) |
9c96033c | 5746 | return false; |
2055d27a | 5747 | if (!RECUR (TREE_OPERAND (t, 2), rval)) |
9c96033c | 5748 | return false; |
5749 | return true; | |
5750 | ||
9c96033c | 5751 | case DO_STMT: |
2055d27a | 5752 | if (!RECUR (DO_COND (t), rval)) |
9c96033c | 5753 | return false; |
2055d27a | 5754 | if (!RECUR (DO_BODY (t), any)) |
9c96033c | 5755 | return false; |
5756 | return true; | |
5757 | ||
5758 | case FOR_STMT: | |
2055d27a | 5759 | if (!RECUR (FOR_INIT_STMT (t), any)) |
9c96033c | 5760 | return false; |
2055d27a | 5761 | if (!RECUR (FOR_COND (t), rval)) |
9c96033c | 5762 | return false; |
2055d27a | 5763 | if (!RECUR (FOR_EXPR (t), any)) |
9c96033c | 5764 | return false; |
2055d27a | 5765 | if (!RECUR (FOR_BODY (t), any)) |
9c96033c | 5766 | return false; |
5767 | return true; | |
5768 | ||
33603066 | 5769 | case RANGE_FOR_STMT: |
5770 | if (!RECUR (RANGE_FOR_EXPR (t), any)) | |
5771 | return false; | |
5772 | if (!RECUR (RANGE_FOR_BODY (t), any)) | |
5773 | return false; | |
5774 | return true; | |
5775 | ||
9c96033c | 5776 | case WHILE_STMT: |
2055d27a | 5777 | if (!RECUR (WHILE_COND (t), rval)) |
9c96033c | 5778 | return false; |
2055d27a | 5779 | if (!RECUR (WHILE_BODY (t), any)) |
9c96033c | 5780 | return false; |
5781 | return true; | |
5782 | ||
5783 | case SWITCH_STMT: | |
2055d27a | 5784 | if (!RECUR (SWITCH_STMT_COND (t), rval)) |
9c96033c | 5785 | return false; |
748c426a | 5786 | /* FIXME we don't check SWITCH_STMT_BODY currently, because even |
5787 | unreachable labels would be checked. */ | |
9c96033c | 5788 | return true; |
5789 | ||
da7981e0 | 5790 | case STMT_EXPR: |
2055d27a | 5791 | return RECUR (STMT_EXPR_STMT (t), rval); |
da7981e0 | 5792 | |
09b42213 | 5793 | case LAMBDA_EXPR: |
27db1f50 | 5794 | if (cxx_dialect >= cxx17) |
5795 | /* In C++17 lambdas can be constexpr, don't give up yet. */ | |
5796 | return true; | |
5797 | else if (flags & tf_error) | |
5798 | error_at (loc, "lambda-expression is not a constant expression " | |
5799 | "before C++17"); | |
5800 | return false; | |
5801 | ||
09b42213 | 5802 | case DYNAMIC_CAST_EXPR: |
5803 | case PSEUDO_DTOR_EXPR: | |
09b42213 | 5804 | case NEW_EXPR: |
5805 | case VEC_NEW_EXPR: | |
5806 | case DELETE_EXPR: | |
5807 | case VEC_DELETE_EXPR: | |
5808 | case THROW_EXPR: | |
d6a08f5c | 5809 | case OMP_PARALLEL: |
5810 | case OMP_TASK: | |
5811 | case OMP_FOR: | |
83728168 | 5812 | case OMP_SIMD: |
d6a08f5c | 5813 | case OMP_DISTRIBUTE: |
5814 | case OMP_TASKLOOP: | |
5815 | case OMP_TEAMS: | |
5816 | case OMP_TARGET_DATA: | |
5817 | case OMP_TARGET: | |
5818 | case OMP_SECTIONS: | |
5819 | case OMP_ORDERED: | |
5820 | case OMP_CRITICAL: | |
5821 | case OMP_SINGLE: | |
5822 | case OMP_SECTION: | |
5823 | case OMP_MASTER: | |
5824 | case OMP_TASKGROUP: | |
5825 | case OMP_TARGET_UPDATE: | |
5826 | case OMP_TARGET_ENTER_DATA: | |
5827 | case OMP_TARGET_EXIT_DATA: | |
09b42213 | 5828 | case OMP_ATOMIC: |
5829 | case OMP_ATOMIC_READ: | |
5830 | case OMP_ATOMIC_CAPTURE_OLD: | |
5831 | case OMP_ATOMIC_CAPTURE_NEW: | |
d6a08f5c | 5832 | case OACC_PARALLEL: |
5833 | case OACC_KERNELS: | |
5834 | case OACC_DATA: | |
5835 | case OACC_HOST_DATA: | |
5836 | case OACC_LOOP: | |
5837 | case OACC_CACHE: | |
5838 | case OACC_DECLARE: | |
5839 | case OACC_ENTER_DATA: | |
5840 | case OACC_EXIT_DATA: | |
5841 | case OACC_UPDATE: | |
09b42213 | 5842 | /* GCC internal stuff. */ |
5843 | case VA_ARG_EXPR: | |
5844 | case OBJ_TYPE_REF: | |
09b42213 | 5845 | case TRANSACTION_EXPR: |
9c96033c | 5846 | case ASM_EXPR: |
9abecca2 | 5847 | case AT_ENCODE_EXPR: |
9c96033c | 5848 | fail: |
09b42213 | 5849 | if (flags & tf_error) |
d6a08f5c | 5850 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 5851 | return false; |
5852 | ||
5853 | case TYPEID_EXPR: | |
5854 | /* -- a typeid expression whose operand is of polymorphic | |
5855 | class type; */ | |
5856 | { | |
5857 | tree e = TREE_OPERAND (t, 0); | |
5858 | if (!TYPE_P (e) && !type_dependent_expression_p (e) | |
5859 | && TYPE_POLYMORPHIC_P (TREE_TYPE (e))) | |
5860 | { | |
5861 | if (flags & tf_error) | |
d6a08f5c | 5862 | error_at (loc, "typeid-expression is not a constant expression " |
5863 | "because %qE is of polymorphic type", e); | |
09b42213 | 5864 | return false; |
5865 | } | |
5866 | return true; | |
5867 | } | |
5868 | ||
57e83b58 | 5869 | case POINTER_DIFF_EXPR: |
09b42213 | 5870 | case MINUS_EXPR: |
09b42213 | 5871 | want_rval = true; |
5872 | goto binary; | |
5873 | ||
5874 | case LT_EXPR: | |
5875 | case LE_EXPR: | |
5876 | case GT_EXPR: | |
5877 | case GE_EXPR: | |
5878 | case EQ_EXPR: | |
5879 | case NE_EXPR: | |
09b42213 | 5880 | want_rval = true; |
5881 | goto binary; | |
5882 | ||
9c96033c | 5883 | case PREINCREMENT_EXPR: |
5884 | case POSTINCREMENT_EXPR: | |
5885 | case PREDECREMENT_EXPR: | |
5886 | case POSTDECREMENT_EXPR: | |
5887 | if (cxx_dialect < cxx14) | |
5888 | goto fail; | |
5889 | goto unary; | |
5890 | ||
09b42213 | 5891 | case BIT_NOT_EXPR: |
5892 | /* A destructor. */ | |
5893 | if (TYPE_P (TREE_OPERAND (t, 0))) | |
5894 | return true; | |
e3533433 | 5895 | /* fall through. */ |
09b42213 | 5896 | |
09b42213 | 5897 | case CONJ_EXPR: |
5898 | case SAVE_EXPR: | |
5899 | case FIX_TRUNC_EXPR: | |
5900 | case FLOAT_EXPR: | |
5901 | case NEGATE_EXPR: | |
5902 | case ABS_EXPR: | |
1c67942e | 5903 | case ABSU_EXPR: |
09b42213 | 5904 | case TRUTH_NOT_EXPR: |
5905 | case FIXED_CONVERT_EXPR: | |
5906 | case UNARY_PLUS_EXPR: | |
6fdf70f5 | 5907 | case UNARY_LEFT_FOLD_EXPR: |
5908 | case UNARY_RIGHT_FOLD_EXPR: | |
9c96033c | 5909 | unary: |
2055d27a | 5910 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 5911 | |
5912 | case CAST_EXPR: | |
5913 | case CONST_CAST_EXPR: | |
5914 | case STATIC_CAST_EXPR: | |
5915 | case REINTERPRET_CAST_EXPR: | |
5916 | case IMPLICIT_CONV_EXPR: | |
5917 | if (cxx_dialect < cxx11 | |
5918 | && !dependent_type_p (TREE_TYPE (t)) | |
5919 | && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t))) | |
5920 | /* In C++98, a conversion to non-integral type can't be part of a | |
5921 | constant expression. */ | |
5922 | { | |
5923 | if (flags & tf_error) | |
d6a08f5c | 5924 | error_at (loc, |
5925 | "cast to non-integral type %qT in a constant expression", | |
5926 | TREE_TYPE (t)); | |
09b42213 | 5927 | return false; |
5928 | } | |
e0ccd480 | 5929 | /* This might be a conversion from a class to a (potentially) literal |
5930 | type. Let's consider it potentially constant since the conversion | |
5931 | might be a constexpr user-defined conversion. */ | |
5932 | else if (cxx_dialect >= cxx11 | |
5933 | && (dependent_type_p (TREE_TYPE (t)) | |
5934 | || !COMPLETE_TYPE_P (TREE_TYPE (t)) | |
5935 | || literal_type_p (TREE_TYPE (t))) | |
5936 | && TREE_OPERAND (t, 0)) | |
5937 | { | |
5938 | tree type = TREE_TYPE (TREE_OPERAND (t, 0)); | |
5939 | /* If this is a dependent type, it could end up being a class | |
5940 | with conversions. */ | |
5941 | if (type == NULL_TREE || WILDCARD_TYPE_P (type)) | |
5942 | return true; | |
5943 | /* Or a non-dependent class which has conversions. */ | |
5944 | else if (CLASS_TYPE_P (type) | |
5945 | && (TYPE_HAS_CONVERSION (type) || dependent_scope_p (type))) | |
5946 | return true; | |
5947 | } | |
09b42213 | 5948 | |
2055d27a | 5949 | return (RECUR (TREE_OPERAND (t, 0), |
90ad495b | 5950 | !TYPE_REF_P (TREE_TYPE (t)))); |
09b42213 | 5951 | |
9c96033c | 5952 | case BIND_EXPR: |
2055d27a | 5953 | return RECUR (BIND_EXPR_BODY (t), want_rval); |
9c96033c | 5954 | |
9c96033c | 5955 | case CLEANUP_POINT_EXPR: |
5956 | case MUST_NOT_THROW_EXPR: | |
5957 | case TRY_CATCH_EXPR: | |
7f67d68c | 5958 | case TRY_BLOCK: |
9c96033c | 5959 | case EH_SPEC_BLOCK: |
5960 | case EXPR_STMT: | |
09b42213 | 5961 | case PAREN_EXPR: |
5962 | case NON_DEPENDENT_EXPR: | |
5963 | /* For convenience. */ | |
5964 | case RETURN_EXPR: | |
d1980671 | 5965 | case LOOP_EXPR: |
5966 | case EXIT_EXPR: | |
2055d27a | 5967 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5968 | |
33603066 | 5969 | case DECL_EXPR: |
5970 | tmp = DECL_EXPR_DECL (t); | |
5971 | if (VAR_P (tmp) && !DECL_ARTIFICIAL (tmp)) | |
5972 | { | |
5973 | if (TREE_STATIC (tmp)) | |
5974 | { | |
5975 | if (flags & tf_error) | |
5976 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 5977 | "%<static%> in %<constexpr%> context", tmp); |
33603066 | 5978 | return false; |
5979 | } | |
5980 | else if (CP_DECL_THREAD_LOCAL_P (tmp)) | |
5981 | { | |
5982 | if (flags & tf_error) | |
5983 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 5984 | "%<thread_local%> in %<constexpr%> context", tmp); |
33603066 | 5985 | return false; |
5986 | } | |
282ea908 | 5987 | else if (!check_for_uninitialized_const_var |
5988 | (tmp, /*constexpr_context_p=*/true, flags)) | |
5989 | return false; | |
33603066 | 5990 | } |
5991 | return RECUR (tmp, want_rval); | |
5992 | ||
7f67d68c | 5993 | case TRY_FINALLY_EXPR: |
5994 | return (RECUR (TREE_OPERAND (t, 0), want_rval) | |
5995 | && RECUR (TREE_OPERAND (t, 1), any)); | |
5996 | ||
09b42213 | 5997 | case SCOPE_REF: |
2055d27a | 5998 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 5999 | |
6000 | case TARGET_EXPR: | |
07d8961c | 6001 | if (!TARGET_EXPR_DIRECT_INIT_P (t) |
6002 | && !literal_type_p (TREE_TYPE (t))) | |
09b42213 | 6003 | { |
6004 | if (flags & tf_error) | |
6005 | { | |
bc35ef65 | 6006 | auto_diagnostic_group d; |
d6a08f5c | 6007 | error_at (loc, "temporary of non-literal type %qT in a " |
6008 | "constant expression", TREE_TYPE (t)); | |
09b42213 | 6009 | explain_non_literal_class (TREE_TYPE (t)); |
6010 | } | |
6011 | return false; | |
6012 | } | |
e3533433 | 6013 | /* FALLTHRU */ |
09b42213 | 6014 | case INIT_EXPR: |
2055d27a | 6015 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 6016 | |
6017 | case CONSTRUCTOR: | |
6018 | { | |
6019 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
6020 | constructor_elt *ce; | |
6021 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2055d27a | 6022 | if (!RECUR (ce->value, want_rval)) |
09b42213 | 6023 | return false; |
6024 | return true; | |
6025 | } | |
6026 | ||
6027 | case TREE_LIST: | |
6028 | { | |
6029 | gcc_assert (TREE_PURPOSE (t) == NULL_TREE | |
6030 | || DECL_P (TREE_PURPOSE (t))); | |
2055d27a | 6031 | if (!RECUR (TREE_VALUE (t), want_rval)) |
09b42213 | 6032 | return false; |
6033 | if (TREE_CHAIN (t) == NULL_TREE) | |
6034 | return true; | |
2055d27a | 6035 | return RECUR (TREE_CHAIN (t), want_rval); |
09b42213 | 6036 | } |
6037 | ||
6038 | case TRUNC_DIV_EXPR: | |
6039 | case CEIL_DIV_EXPR: | |
6040 | case FLOOR_DIV_EXPR: | |
6041 | case ROUND_DIV_EXPR: | |
6042 | case TRUNC_MOD_EXPR: | |
6043 | case CEIL_MOD_EXPR: | |
6044 | case ROUND_MOD_EXPR: | |
6045 | { | |
6046 | tree denom = TREE_OPERAND (t, 1); | |
2055d27a | 6047 | if (!RECUR (denom, rval)) |
09b42213 | 6048 | return false; |
6049 | /* We can't call cxx_eval_outermost_constant_expr on an expression | |
21131a05 | 6050 | that hasn't been through instantiate_non_dependent_expr yet. */ |
09b42213 | 6051 | if (!processing_template_decl) |
6052 | denom = cxx_eval_outermost_constant_expr (denom, true); | |
6053 | if (integer_zerop (denom)) | |
6054 | { | |
6055 | if (flags & tf_error) | |
ea034e2c | 6056 | error ("division by zero is not a constant expression"); |
09b42213 | 6057 | return false; |
6058 | } | |
6059 | else | |
6060 | { | |
6061 | want_rval = true; | |
2055d27a | 6062 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 6063 | } |
6064 | } | |
6065 | ||
6066 | case COMPOUND_EXPR: | |
6067 | { | |
6068 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
6069 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
6070 | introduced by build_call_a. */ | |
6071 | tree op0 = TREE_OPERAND (t, 0); | |
6072 | tree op1 = TREE_OPERAND (t, 1); | |
6073 | STRIP_NOPS (op1); | |
6074 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
6075 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
2055d27a | 6076 | return RECUR (op0, want_rval); |
09b42213 | 6077 | else |
6078 | goto binary; | |
6079 | } | |
6080 | ||
6081 | /* If the first operand is the non-short-circuit constant, look at | |
6082 | the second operand; otherwise we only care about the first one for | |
6083 | potentiality. */ | |
6084 | case TRUTH_AND_EXPR: | |
6085 | case TRUTH_ANDIF_EXPR: | |
6086 | tmp = boolean_true_node; | |
6087 | goto truth; | |
6088 | case TRUTH_OR_EXPR: | |
6089 | case TRUTH_ORIF_EXPR: | |
6090 | tmp = boolean_false_node; | |
6091 | truth: | |
6092 | { | |
6093 | tree op = TREE_OPERAND (t, 0); | |
2055d27a | 6094 | if (!RECUR (op, rval)) |
09b42213 | 6095 | return false; |
6096 | if (!processing_template_decl) | |
6097 | op = cxx_eval_outermost_constant_expr (op, true); | |
6098 | if (tree_int_cst_equal (op, tmp)) | |
2055d27a | 6099 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 6100 | else |
6101 | return true; | |
6102 | } | |
6103 | ||
6104 | case PLUS_EXPR: | |
6105 | case MULT_EXPR: | |
6106 | case POINTER_PLUS_EXPR: | |
6107 | case RDIV_EXPR: | |
6108 | case EXACT_DIV_EXPR: | |
6109 | case MIN_EXPR: | |
6110 | case MAX_EXPR: | |
6111 | case LSHIFT_EXPR: | |
6112 | case RSHIFT_EXPR: | |
6113 | case LROTATE_EXPR: | |
6114 | case RROTATE_EXPR: | |
6115 | case BIT_IOR_EXPR: | |
6116 | case BIT_XOR_EXPR: | |
6117 | case BIT_AND_EXPR: | |
6118 | case TRUTH_XOR_EXPR: | |
6119 | case UNORDERED_EXPR: | |
6120 | case ORDERED_EXPR: | |
6121 | case UNLT_EXPR: | |
6122 | case UNLE_EXPR: | |
6123 | case UNGT_EXPR: | |
6124 | case UNGE_EXPR: | |
6125 | case UNEQ_EXPR: | |
6126 | case LTGT_EXPR: | |
6127 | case RANGE_EXPR: | |
6128 | case COMPLEX_EXPR: | |
6129 | want_rval = true; | |
6130 | /* Fall through. */ | |
6131 | case ARRAY_REF: | |
6132 | case ARRAY_RANGE_REF: | |
6133 | case MEMBER_REF: | |
6134 | case DOTSTAR_EXPR: | |
f0abe78f | 6135 | case MEM_REF: |
6fdf70f5 | 6136 | case BINARY_LEFT_FOLD_EXPR: |
6137 | case BINARY_RIGHT_FOLD_EXPR: | |
09b42213 | 6138 | binary: |
6139 | for (i = 0; i < 2; ++i) | |
2055d27a | 6140 | if (!RECUR (TREE_OPERAND (t, i), want_rval)) |
09b42213 | 6141 | return false; |
6142 | return true; | |
6143 | ||
09b42213 | 6144 | case VEC_PERM_EXPR: |
6145 | for (i = 0; i < 3; ++i) | |
2055d27a | 6146 | if (!RECUR (TREE_OPERAND (t, i), true)) |
09b42213 | 6147 | return false; |
6148 | return true; | |
6149 | ||
6150 | case COND_EXPR: | |
b0fe8b95 | 6151 | if (COND_EXPR_IS_VEC_DELETE (t)) |
6152 | { | |
6153 | if (flags & tf_error) | |
d6a08f5c | 6154 | error_at (loc, "%<delete[]%> is not a constant expression"); |
b0fe8b95 | 6155 | return false; |
6156 | } | |
6157 | /* Fall through. */ | |
6158 | case IF_STMT: | |
09b42213 | 6159 | case VEC_COND_EXPR: |
6160 | /* If the condition is a known constant, we know which of the legs we | |
6161 | care about; otherwise we only require that the condition and | |
6162 | either of the legs be potentially constant. */ | |
6163 | tmp = TREE_OPERAND (t, 0); | |
2055d27a | 6164 | if (!RECUR (tmp, rval)) |
09b42213 | 6165 | return false; |
6166 | if (!processing_template_decl) | |
6167 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
6168 | if (integer_zerop (tmp)) | |
2055d27a | 6169 | return RECUR (TREE_OPERAND (t, 2), want_rval); |
09b42213 | 6170 | else if (TREE_CODE (tmp) == INTEGER_CST) |
2055d27a | 6171 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 6172 | for (i = 1; i < 3; ++i) |
6173 | if (potential_constant_expression_1 (TREE_OPERAND (t, i), | |
7e1f8be4 | 6174 | want_rval, strict, now, tf_none)) |
09b42213 | 6175 | return true; |
6176 | if (flags & tf_error) | |
d6a08f5c | 6177 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 6178 | return false; |
6179 | ||
6180 | case VEC_INIT_EXPR: | |
6181 | if (VEC_INIT_EXPR_IS_CONSTEXPR (t)) | |
6182 | return true; | |
6183 | if (flags & tf_error) | |
6184 | { | |
d6a08f5c | 6185 | error_at (loc, "non-constant array initialization"); |
09b42213 | 6186 | diagnose_non_constexpr_vec_init (t); |
6187 | } | |
6188 | return false; | |
6189 | ||
db1ae94f | 6190 | case TYPE_DECL: |
6191 | case TAG_DEFN: | |
6192 | /* We can see these in statement-expressions. */ | |
6193 | return true; | |
6194 | ||
fd130325 | 6195 | case CLEANUP_STMT: |
d2c63826 | 6196 | case EMPTY_CLASS_EXPR: |
38ef3642 | 6197 | case PREDICT_EXPR: |
d2c63826 | 6198 | return false; |
6199 | ||
d1980671 | 6200 | case GOTO_EXPR: |
6201 | { | |
6202 | tree *target = &TREE_OPERAND (t, 0); | |
d40a1eac | 6203 | /* Gotos representing break and continue are OK. */ |
6204 | if (breaks (target) || continues (target)) | |
6205 | return true; | |
6206 | if (flags & tf_error) | |
d6a08f5c | 6207 | error_at (loc, "%<goto%> is not a constant expression"); |
d40a1eac | 6208 | return false; |
d1980671 | 6209 | } |
6210 | ||
24c6ee98 | 6211 | case ANNOTATE_EXPR: |
24c6ee98 | 6212 | return RECUR (TREE_OPERAND (t, 0), rval); |
6213 | ||
09b42213 | 6214 | default: |
6215 | if (objc_is_property_ref (t)) | |
6216 | return false; | |
6217 | ||
6218 | sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t))); | |
d40a1eac | 6219 | gcc_unreachable (); |
09b42213 | 6220 | return false; |
6221 | } | |
2055d27a | 6222 | #undef RECUR |
09b42213 | 6223 | } |
6224 | ||
6225 | /* The main entry point to the above. */ | |
6226 | ||
6227 | bool | |
6228 | potential_constant_expression (tree t) | |
6229 | { | |
7e1f8be4 | 6230 | return potential_constant_expression_1 (t, false, true, false, tf_none); |
09b42213 | 6231 | } |
6232 | ||
6233 | /* As above, but require a constant rvalue. */ | |
6234 | ||
6235 | bool | |
6236 | potential_rvalue_constant_expression (tree t) | |
6237 | { | |
7e1f8be4 | 6238 | return potential_constant_expression_1 (t, true, true, false, tf_none); |
09b42213 | 6239 | } |
6240 | ||
6241 | /* Like above, but complain about non-constant expressions. */ | |
6242 | ||
6243 | bool | |
6244 | require_potential_constant_expression (tree t) | |
6245 | { | |
786721dc | 6246 | return potential_constant_expression_1 (t, false, true, false, |
6247 | tf_warning_or_error); | |
09b42213 | 6248 | } |
6249 | ||
6250 | /* Cross product of the above. */ | |
6251 | ||
6252 | bool | |
6253 | require_potential_rvalue_constant_expression (tree t) | |
6254 | { | |
786721dc | 6255 | return potential_constant_expression_1 (t, true, true, false, |
6256 | tf_warning_or_error); | |
6257 | } | |
6258 | ||
6259 | /* Like above, but don't consider PARM_DECL a potential_constant_expression. */ | |
6260 | ||
6261 | bool | |
6262 | require_rvalue_constant_expression (tree t) | |
6263 | { | |
6264 | return potential_constant_expression_1 (t, true, true, true, | |
6265 | tf_warning_or_error); | |
7e1f8be4 | 6266 | } |
6267 | ||
6268 | /* Like potential_constant_expression, but don't consider possible constexpr | |
6269 | substitution of the current function. That is, PARM_DECL qualifies under | |
6270 | potential_constant_expression, but not here. | |
6271 | ||
6272 | This is basically what you can check when any actual constant values might | |
6273 | be value-dependent. */ | |
6274 | ||
6275 | bool | |
6276 | is_constant_expression (tree t) | |
6277 | { | |
6278 | return potential_constant_expression_1 (t, false, true, true, tf_none); | |
6279 | } | |
6280 | ||
6281 | /* Like above, but complain about non-constant expressions. */ | |
6282 | ||
6283 | bool | |
6284 | require_constant_expression (tree t) | |
6285 | { | |
6286 | return potential_constant_expression_1 (t, false, true, true, | |
6287 | tf_warning_or_error); | |
6288 | } | |
6289 | ||
6290 | /* Like is_constant_expression, but allow const variables that are not allowed | |
6291 | under constexpr rules. */ | |
6292 | ||
6293 | bool | |
6294 | is_static_init_expression (tree t) | |
6295 | { | |
6296 | return potential_constant_expression_1 (t, false, false, true, tf_none); | |
09b42213 | 6297 | } |
6298 | ||
29cf24ec | 6299 | /* Returns true if T is a potential constant expression that is not |
6300 | instantiation-dependent, and therefore a candidate for constant folding even | |
6301 | in a template. */ | |
6302 | ||
6303 | bool | |
7e1f8be4 | 6304 | is_nondependent_constant_expression (tree t) |
29cf24ec | 6305 | { |
6306 | return (!type_unknown_p (t) | |
6307 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6308 | && is_constant_expression (t) |
29cf24ec | 6309 | && !instantiation_dependent_expression_p (t)); |
6310 | } | |
6311 | ||
6312 | /* Returns true if T is a potential static initializer expression that is not | |
6313 | instantiation-dependent. */ | |
6314 | ||
6315 | bool | |
7e1f8be4 | 6316 | is_nondependent_static_init_expression (tree t) |
29cf24ec | 6317 | { |
6318 | return (!type_unknown_p (t) | |
6319 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6320 | && is_static_init_expression (t) |
29cf24ec | 6321 | && !instantiation_dependent_expression_p (t)); |
6322 | } | |
6323 | ||
a050099a | 6324 | /* Finalize constexpr processing after parsing. */ |
6325 | ||
6326 | void | |
6327 | fini_constexpr (void) | |
6328 | { | |
6329 | /* The contexpr call and fundef copies tables are no longer needed. */ | |
6330 | constexpr_call_table = NULL; | |
6331 | fundef_copies_table = NULL; | |
6332 | } | |
6333 | ||
09b42213 | 6334 | #include "gt-cp-constexpr.h" |