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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; |
04e6d9db | 101 | error_at (DECL_SOURCE_LOCATION (decl), |
102 | "the type %qT of %<constexpr%> variable %qD " | |
103 | "is not literal", type, decl); | |
e45408ff | 104 | explain_non_literal_class (type); |
e89257db | 105 | decl = error_mark_node; |
e45408ff | 106 | } |
09b42213 | 107 | else |
9c96033c | 108 | { |
b7e4a558 | 109 | if (!is_instantiation_of_constexpr (current_function_decl)) |
e45408ff | 110 | { |
bc35ef65 | 111 | auto_diagnostic_group d; |
04e6d9db | 112 | error_at (DECL_SOURCE_LOCATION (decl), |
113 | "variable %qD of non-literal type %qT in " | |
114 | "%<constexpr%> function", decl, type); | |
e45408ff | 115 | explain_non_literal_class (type); |
e89257db | 116 | decl = error_mark_node; |
e45408ff | 117 | } |
9c96033c | 118 | cp_function_chain->invalid_constexpr = true; |
119 | } | |
09b42213 | 120 | } |
fdafeeb7 | 121 | else if (DECL_DECLARED_CONSTEXPR_P (decl) |
122 | && variably_modified_type_p (type, NULL_TREE)) | |
123 | { | |
04e6d9db | 124 | error_at (DECL_SOURCE_LOCATION (decl), |
125 | "%<constexpr%> variable %qD has variably-modified " | |
126 | "type %qT", decl, type); | |
fdafeeb7 | 127 | decl = error_mark_node; |
128 | } | |
09b42213 | 129 | } |
130 | return decl; | |
131 | } | |
132 | ||
133 | /* Representation of entries in the constexpr function definition table. */ | |
134 | ||
135 | struct GTY((for_user)) constexpr_fundef { | |
136 | tree decl; | |
137 | tree body; | |
138 | }; | |
139 | ||
b594087e | 140 | struct constexpr_fundef_hasher : ggc_ptr_hash<constexpr_fundef> |
09b42213 | 141 | { |
142 | static hashval_t hash (constexpr_fundef *); | |
143 | static bool equal (constexpr_fundef *, constexpr_fundef *); | |
144 | }; | |
145 | ||
146 | /* This table holds all constexpr function definitions seen in | |
147 | the current translation unit. */ | |
148 | ||
149 | static GTY (()) hash_table<constexpr_fundef_hasher> *constexpr_fundef_table; | |
150 | ||
151 | /* Utility function used for managing the constexpr function table. | |
152 | Return true if the entries pointed to by P and Q are for the | |
153 | same constexpr function. */ | |
154 | ||
155 | inline bool | |
156 | constexpr_fundef_hasher::equal (constexpr_fundef *lhs, constexpr_fundef *rhs) | |
157 | { | |
158 | return lhs->decl == rhs->decl; | |
159 | } | |
160 | ||
161 | /* Utility function used for managing the constexpr function table. | |
162 | Return a hash value for the entry pointed to by Q. */ | |
163 | ||
164 | inline hashval_t | |
165 | constexpr_fundef_hasher::hash (constexpr_fundef *fundef) | |
166 | { | |
167 | return DECL_UID (fundef->decl); | |
168 | } | |
169 | ||
170 | /* Return a previously saved definition of function FUN. */ | |
171 | ||
172 | static constexpr_fundef * | |
173 | retrieve_constexpr_fundef (tree fun) | |
174 | { | |
175 | constexpr_fundef fundef = { NULL, NULL }; | |
176 | if (constexpr_fundef_table == NULL) | |
177 | return NULL; | |
178 | ||
179 | fundef.decl = fun; | |
180 | return constexpr_fundef_table->find (&fundef); | |
181 | } | |
182 | ||
183 | /* Check whether the parameter and return types of FUN are valid for a | |
184 | constexpr function, and complain if COMPLAIN. */ | |
185 | ||
33603066 | 186 | bool |
09b42213 | 187 | is_valid_constexpr_fn (tree fun, bool complain) |
188 | { | |
189 | bool ret = true; | |
190 | ||
7896267d | 191 | if (DECL_INHERITED_CTOR (fun) |
09b42213 | 192 | && TREE_CODE (fun) == TEMPLATE_DECL) |
193 | { | |
194 | ret = false; | |
195 | if (complain) | |
5967b28b | 196 | error ("inherited constructor %qD is not %<constexpr%>", |
7896267d | 197 | DECL_INHERITED_CTOR (fun)); |
09b42213 | 198 | } |
199 | else | |
200 | { | |
201 | for (tree parm = FUNCTION_FIRST_USER_PARM (fun); | |
202 | parm != NULL_TREE; parm = TREE_CHAIN (parm)) | |
203 | if (!literal_type_p (TREE_TYPE (parm))) | |
204 | { | |
205 | ret = false; | |
206 | if (complain) | |
207 | { | |
bc35ef65 | 208 | auto_diagnostic_group d; |
5967b28b | 209 | error ("invalid type for parameter %d of %<constexpr%> " |
09b42213 | 210 | "function %q+#D", DECL_PARM_INDEX (parm), fun); |
211 | explain_non_literal_class (TREE_TYPE (parm)); | |
212 | } | |
213 | } | |
214 | } | |
215 | ||
672871ce | 216 | if (LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) && cxx_dialect < cxx17) |
217 | { | |
218 | ret = false; | |
219 | if (complain) | |
220 | inform (DECL_SOURCE_LOCATION (fun), | |
5967b28b | 221 | "lambdas are implicitly %<constexpr%> only in C++17 and later"); |
672871ce | 222 | } |
223 | else if (!DECL_CONSTRUCTOR_P (fun)) | |
09b42213 | 224 | { |
225 | tree rettype = TREE_TYPE (TREE_TYPE (fun)); | |
226 | if (!literal_type_p (rettype)) | |
227 | { | |
228 | ret = false; | |
229 | if (complain) | |
230 | { | |
bc35ef65 | 231 | auto_diagnostic_group d; |
5967b28b | 232 | error ("invalid return type %qT of %<constexpr%> function %q+D", |
09b42213 | 233 | rettype, fun); |
234 | explain_non_literal_class (rettype); | |
235 | } | |
236 | } | |
237 | ||
d66f34cf | 238 | /* C++14 DR 1684 removed this restriction. */ |
239 | if (cxx_dialect < cxx14 | |
240 | && DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
09b42213 | 241 | && !CLASSTYPE_LITERAL_P (DECL_CONTEXT (fun))) |
242 | { | |
243 | ret = false; | |
bc35ef65 | 244 | if (complain) |
245 | { | |
246 | auto_diagnostic_group d; | |
247 | if (pedwarn (DECL_SOURCE_LOCATION (fun), OPT_Wpedantic, | |
248 | "enclosing class of %<constexpr%> non-static" | |
249 | " member function %q+#D is not a literal type", | |
250 | fun)) | |
251 | explain_non_literal_class (DECL_CONTEXT (fun)); | |
252 | } | |
09b42213 | 253 | } |
254 | } | |
255 | else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun))) | |
256 | { | |
257 | ret = false; | |
258 | if (complain) | |
259 | error ("%q#T has virtual base classes", DECL_CONTEXT (fun)); | |
260 | } | |
261 | ||
262 | return ret; | |
263 | } | |
264 | ||
265 | /* Subroutine of build_data_member_initialization. MEMBER is a COMPONENT_REF | |
266 | for a member of an anonymous aggregate, INIT is the initializer for that | |
267 | member, and VEC_OUTER is the vector of constructor elements for the class | |
268 | whose constructor we are processing. Add the initializer to the vector | |
269 | and return true to indicate success. */ | |
270 | ||
271 | static bool | |
272 | build_anon_member_initialization (tree member, tree init, | |
273 | vec<constructor_elt, va_gc> **vec_outer) | |
274 | { | |
275 | /* MEMBER presents the relevant fields from the inside out, but we need | |
276 | to build up the initializer from the outside in so that we can reuse | |
277 | previously built CONSTRUCTORs if this is, say, the second field in an | |
278 | anonymous struct. So we use a vec as a stack. */ | |
279 | auto_vec<tree, 2> fields; | |
280 | do | |
281 | { | |
282 | fields.safe_push (TREE_OPERAND (member, 1)); | |
283 | member = TREE_OPERAND (member, 0); | |
284 | } | |
285 | while (ANON_AGGR_TYPE_P (TREE_TYPE (member)) | |
286 | && TREE_CODE (member) == COMPONENT_REF); | |
287 | ||
288 | /* VEC has the constructor elements vector for the context of FIELD. | |
289 | If FIELD is an anonymous aggregate, we will push inside it. */ | |
290 | vec<constructor_elt, va_gc> **vec = vec_outer; | |
291 | tree field; | |
292 | while (field = fields.pop(), | |
293 | ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
294 | { | |
295 | tree ctor; | |
296 | /* If there is already an outer constructor entry for the anonymous | |
297 | aggregate FIELD, use it; otherwise, insert one. */ | |
298 | if (vec_safe_is_empty (*vec) | |
299 | || (*vec)->last().index != field) | |
300 | { | |
301 | ctor = build_constructor (TREE_TYPE (field), NULL); | |
302 | CONSTRUCTOR_APPEND_ELT (*vec, field, ctor); | |
303 | } | |
304 | else | |
305 | ctor = (*vec)->last().value; | |
306 | vec = &CONSTRUCTOR_ELTS (ctor); | |
307 | } | |
308 | ||
309 | /* Now we're at the innermost field, the one that isn't an anonymous | |
310 | aggregate. Add its initializer to the CONSTRUCTOR and we're done. */ | |
311 | gcc_assert (fields.is_empty()); | |
312 | CONSTRUCTOR_APPEND_ELT (*vec, field, init); | |
313 | ||
314 | return true; | |
315 | } | |
316 | ||
317 | /* Subroutine of build_constexpr_constructor_member_initializers. | |
318 | The expression tree T represents a data member initialization | |
319 | in a (constexpr) constructor definition. Build a pairing of | |
320 | the data member with its initializer, and prepend that pair | |
321 | to the existing initialization pair INITS. */ | |
322 | ||
323 | static bool | |
324 | build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec) | |
325 | { | |
326 | tree member, init; | |
327 | if (TREE_CODE (t) == CLEANUP_POINT_EXPR) | |
328 | t = TREE_OPERAND (t, 0); | |
329 | if (TREE_CODE (t) == EXPR_STMT) | |
330 | t = TREE_OPERAND (t, 0); | |
331 | if (t == error_mark_node) | |
332 | return false; | |
333 | if (TREE_CODE (t) == STATEMENT_LIST) | |
334 | { | |
335 | tree_stmt_iterator i; | |
336 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
337 | { | |
338 | if (! build_data_member_initialization (tsi_stmt (i), vec)) | |
339 | return false; | |
340 | } | |
341 | return true; | |
342 | } | |
343 | if (TREE_CODE (t) == CLEANUP_STMT) | |
344 | { | |
345 | /* We can't see a CLEANUP_STMT in a constructor for a literal class, | |
346 | but we can in a constexpr constructor for a non-literal class. Just | |
347 | ignore it; either all the initialization will be constant, in which | |
348 | case the cleanup can't run, or it can't be constexpr. | |
349 | Still recurse into CLEANUP_BODY. */ | |
350 | return build_data_member_initialization (CLEANUP_BODY (t), vec); | |
351 | } | |
352 | if (TREE_CODE (t) == CONVERT_EXPR) | |
353 | t = TREE_OPERAND (t, 0); | |
354 | if (TREE_CODE (t) == INIT_EXPR | |
9c96033c | 355 | /* vptr initialization shows up as a MODIFY_EXPR. In C++14 we only |
356 | use what this function builds for cx_check_missing_mem_inits, and | |
357 | assignment in the ctor body doesn't count. */ | |
358 | || (cxx_dialect < cxx14 && TREE_CODE (t) == MODIFY_EXPR)) | |
09b42213 | 359 | { |
360 | member = TREE_OPERAND (t, 0); | |
361 | init = break_out_target_exprs (TREE_OPERAND (t, 1)); | |
362 | } | |
363 | else if (TREE_CODE (t) == CALL_EXPR) | |
364 | { | |
9c96033c | 365 | tree fn = get_callee_fndecl (t); |
366 | if (!fn || !DECL_CONSTRUCTOR_P (fn)) | |
367 | /* We're only interested in calls to subobject constructors. */ | |
368 | return true; | |
09b42213 | 369 | member = CALL_EXPR_ARG (t, 0); |
370 | /* We don't use build_cplus_new here because it complains about | |
371 | abstract bases. Leaving the call unwrapped means that it has the | |
372 | wrong type, but cxx_eval_constant_expression doesn't care. */ | |
373 | init = break_out_target_exprs (t); | |
374 | } | |
375 | else if (TREE_CODE (t) == BIND_EXPR) | |
376 | return build_data_member_initialization (BIND_EXPR_BODY (t), vec); | |
09b42213 | 377 | else |
9c96033c | 378 | /* Don't add anything else to the CONSTRUCTOR. */ |
379 | return true; | |
09b42213 | 380 | if (INDIRECT_REF_P (member)) |
381 | member = TREE_OPERAND (member, 0); | |
382 | if (TREE_CODE (member) == NOP_EXPR) | |
383 | { | |
384 | tree op = member; | |
385 | STRIP_NOPS (op); | |
386 | if (TREE_CODE (op) == ADDR_EXPR) | |
387 | { | |
388 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
389 | (TREE_TYPE (TREE_TYPE (op)), | |
390 | TREE_TYPE (TREE_TYPE (member)))); | |
391 | /* Initializing a cv-qualified member; we need to look through | |
392 | the const_cast. */ | |
393 | member = op; | |
394 | } | |
395 | else if (op == current_class_ptr | |
396 | && (same_type_ignoring_top_level_qualifiers_p | |
397 | (TREE_TYPE (TREE_TYPE (member)), | |
398 | current_class_type))) | |
399 | /* Delegating constructor. */ | |
400 | member = op; | |
401 | else | |
402 | { | |
403 | /* This is an initializer for an empty base; keep it for now so | |
404 | we can check it in cxx_eval_bare_aggregate. */ | |
405 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (member)))); | |
406 | } | |
407 | } | |
408 | if (TREE_CODE (member) == ADDR_EXPR) | |
409 | member = TREE_OPERAND (member, 0); | |
410 | if (TREE_CODE (member) == COMPONENT_REF) | |
411 | { | |
412 | tree aggr = TREE_OPERAND (member, 0); | |
4952bc85 | 413 | if (TREE_CODE (aggr) == VAR_DECL) |
414 | /* Initializing a local variable, don't add anything. */ | |
415 | return true; | |
09b42213 | 416 | if (TREE_CODE (aggr) != COMPONENT_REF) |
417 | /* Normal member initialization. */ | |
418 | member = TREE_OPERAND (member, 1); | |
419 | else if (ANON_AGGR_TYPE_P (TREE_TYPE (aggr))) | |
420 | /* Initializing a member of an anonymous union. */ | |
421 | return build_anon_member_initialization (member, init, vec); | |
422 | else | |
423 | /* We're initializing a vtable pointer in a base. Leave it as | |
424 | COMPONENT_REF so we remember the path to get to the vfield. */ | |
425 | gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node); | |
426 | } | |
427 | ||
c678e23e | 428 | /* Value-initialization can produce multiple initializers for the |
429 | same field; use the last one. */ | |
430 | if (!vec_safe_is_empty (*vec) && (*vec)->last().index == member) | |
431 | (*vec)->last().value = init; | |
432 | else | |
433 | CONSTRUCTOR_APPEND_ELT (*vec, member, init); | |
09b42213 | 434 | return true; |
435 | } | |
436 | ||
437 | /* Subroutine of check_constexpr_ctor_body_1 and constexpr_fn_retval. | |
438 | In C++11 mode checks that the TYPE_DECLs in the BIND_EXPR_VARS of a | |
439 | BIND_EXPR conform to 7.1.5/3/4 on typedef and alias declarations. */ | |
440 | ||
441 | static bool | |
442 | check_constexpr_bind_expr_vars (tree t) | |
443 | { | |
444 | gcc_assert (TREE_CODE (t) == BIND_EXPR); | |
445 | ||
09b42213 | 446 | for (tree var = BIND_EXPR_VARS (t); var; var = DECL_CHAIN (var)) |
447 | if (TREE_CODE (var) == TYPE_DECL | |
04103c39 | 448 | && DECL_IMPLICIT_TYPEDEF_P (var) |
449 | && !LAMBDA_TYPE_P (TREE_TYPE (var))) | |
09b42213 | 450 | return false; |
451 | return true; | |
452 | } | |
453 | ||
454 | /* Subroutine of check_constexpr_ctor_body. */ | |
455 | ||
456 | static bool | |
457 | check_constexpr_ctor_body_1 (tree last, tree list) | |
458 | { | |
459 | switch (TREE_CODE (list)) | |
460 | { | |
461 | case DECL_EXPR: | |
810702a2 | 462 | if (TREE_CODE (DECL_EXPR_DECL (list)) == USING_DECL |
463 | || TREE_CODE (DECL_EXPR_DECL (list)) == TYPE_DECL) | |
09b42213 | 464 | return true; |
09b42213 | 465 | return false; |
466 | ||
467 | case CLEANUP_POINT_EXPR: | |
468 | return check_constexpr_ctor_body (last, TREE_OPERAND (list, 0), | |
469 | /*complain=*/false); | |
470 | ||
471 | case BIND_EXPR: | |
472 | if (!check_constexpr_bind_expr_vars (list) | |
473 | || !check_constexpr_ctor_body (last, BIND_EXPR_BODY (list), | |
474 | /*complain=*/false)) | |
475 | return false; | |
476 | return true; | |
477 | ||
478 | case USING_STMT: | |
479 | case STATIC_ASSERT: | |
90567983 | 480 | case DEBUG_BEGIN_STMT: |
09b42213 | 481 | return true; |
482 | ||
483 | default: | |
484 | return false; | |
485 | } | |
486 | } | |
487 | ||
488 | /* Make sure that there are no statements after LAST in the constructor | |
489 | body represented by LIST. */ | |
490 | ||
491 | bool | |
492 | check_constexpr_ctor_body (tree last, tree list, bool complain) | |
493 | { | |
9c96033c | 494 | /* C++14 doesn't require a constexpr ctor to have an empty body. */ |
495 | if (cxx_dialect >= cxx14) | |
496 | return true; | |
497 | ||
09b42213 | 498 | bool ok = true; |
499 | if (TREE_CODE (list) == STATEMENT_LIST) | |
500 | { | |
501 | tree_stmt_iterator i = tsi_last (list); | |
502 | for (; !tsi_end_p (i); tsi_prev (&i)) | |
503 | { | |
504 | tree t = tsi_stmt (i); | |
505 | if (t == last) | |
506 | break; | |
507 | if (!check_constexpr_ctor_body_1 (last, t)) | |
508 | { | |
509 | ok = false; | |
510 | break; | |
511 | } | |
512 | } | |
513 | } | |
514 | else if (list != last | |
515 | && !check_constexpr_ctor_body_1 (last, list)) | |
516 | ok = false; | |
517 | if (!ok) | |
518 | { | |
519 | if (complain) | |
5967b28b | 520 | error ("%<constexpr%> constructor does not have empty body"); |
09b42213 | 521 | DECL_DECLARED_CONSTEXPR_P (current_function_decl) = false; |
522 | } | |
523 | return ok; | |
524 | } | |
525 | ||
526 | /* V is a vector of constructor elements built up for the base and member | |
527 | initializers of a constructor for TYPE. They need to be in increasing | |
528 | offset order, which they might not be yet if TYPE has a primary base | |
529 | which is not first in the base-clause or a vptr and at least one base | |
530 | all of which are non-primary. */ | |
531 | ||
532 | static vec<constructor_elt, va_gc> * | |
533 | sort_constexpr_mem_initializers (tree type, vec<constructor_elt, va_gc> *v) | |
534 | { | |
535 | tree pri = CLASSTYPE_PRIMARY_BINFO (type); | |
536 | tree field_type; | |
537 | unsigned i; | |
538 | constructor_elt *ce; | |
539 | ||
540 | if (pri) | |
541 | field_type = BINFO_TYPE (pri); | |
542 | else if (TYPE_CONTAINS_VPTR_P (type)) | |
543 | field_type = vtbl_ptr_type_node; | |
544 | else | |
545 | return v; | |
546 | ||
547 | /* Find the element for the primary base or vptr and move it to the | |
548 | beginning of the vec. */ | |
549 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
550 | if (TREE_TYPE (ce->index) == field_type) | |
551 | break; | |
552 | ||
553 | if (i > 0 && i < vec_safe_length (v)) | |
554 | { | |
555 | vec<constructor_elt, va_gc> &vref = *v; | |
556 | constructor_elt elt = vref[i]; | |
557 | for (; i > 0; --i) | |
558 | vref[i] = vref[i-1]; | |
559 | vref[0] = elt; | |
560 | } | |
561 | ||
562 | return v; | |
563 | } | |
564 | ||
565 | /* Build compile-time evalable representations of member-initializer list | |
566 | for a constexpr constructor. */ | |
567 | ||
568 | static tree | |
569 | build_constexpr_constructor_member_initializers (tree type, tree body) | |
570 | { | |
571 | vec<constructor_elt, va_gc> *vec = NULL; | |
572 | bool ok = true; | |
816919e1 | 573 | while (true) |
574 | switch (TREE_CODE (body)) | |
575 | { | |
576 | case MUST_NOT_THROW_EXPR: | |
577 | case EH_SPEC_BLOCK: | |
578 | body = TREE_OPERAND (body, 0); | |
579 | break; | |
580 | ||
581 | case STATEMENT_LIST: | |
582 | for (tree_stmt_iterator i = tsi_start (body); | |
583 | !tsi_end_p (i); tsi_next (&i)) | |
584 | { | |
585 | body = tsi_stmt (i); | |
586 | if (TREE_CODE (body) == BIND_EXPR) | |
587 | break; | |
588 | } | |
589 | break; | |
590 | ||
591 | case BIND_EXPR: | |
592 | body = BIND_EXPR_BODY (body); | |
593 | goto found; | |
594 | ||
595 | default: | |
596 | gcc_unreachable (); | |
8a36d0ec | 597 | } |
816919e1 | 598 | found: |
09b42213 | 599 | if (TREE_CODE (body) == CLEANUP_POINT_EXPR) |
600 | { | |
601 | body = TREE_OPERAND (body, 0); | |
602 | if (TREE_CODE (body) == EXPR_STMT) | |
603 | body = TREE_OPERAND (body, 0); | |
604 | if (TREE_CODE (body) == INIT_EXPR | |
605 | && (same_type_ignoring_top_level_qualifiers_p | |
606 | (TREE_TYPE (TREE_OPERAND (body, 0)), | |
607 | current_class_type))) | |
608 | { | |
609 | /* Trivial copy. */ | |
610 | return TREE_OPERAND (body, 1); | |
611 | } | |
612 | ok = build_data_member_initialization (body, &vec); | |
613 | } | |
614 | else if (TREE_CODE (body) == STATEMENT_LIST) | |
615 | { | |
616 | tree_stmt_iterator i; | |
617 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
618 | { | |
619 | ok = build_data_member_initialization (tsi_stmt (i), &vec); | |
620 | if (!ok) | |
621 | break; | |
622 | } | |
623 | } | |
624 | else if (TREE_CODE (body) == TRY_BLOCK) | |
625 | { | |
626 | error ("body of %<constexpr%> constructor cannot be " | |
627 | "a function-try-block"); | |
628 | return error_mark_node; | |
629 | } | |
630 | else if (EXPR_P (body)) | |
631 | ok = build_data_member_initialization (body, &vec); | |
632 | else | |
633 | gcc_assert (errorcount > 0); | |
634 | if (ok) | |
635 | { | |
636 | if (vec_safe_length (vec) > 0) | |
637 | { | |
638 | /* In a delegating constructor, return the target. */ | |
639 | constructor_elt *ce = &(*vec)[0]; | |
640 | if (ce->index == current_class_ptr) | |
641 | { | |
642 | body = ce->value; | |
643 | vec_free (vec); | |
644 | return body; | |
645 | } | |
646 | } | |
647 | vec = sort_constexpr_mem_initializers (type, vec); | |
648 | return build_constructor (type, vec); | |
649 | } | |
650 | else | |
651 | return error_mark_node; | |
652 | } | |
653 | ||
2fb20ba2 | 654 | /* We have an expression tree T that represents a call, either CALL_EXPR |
655 | or AGGR_INIT_EXPR. If the call is lexically to a named function, | |
656 | retrun the _DECL for that function. */ | |
657 | ||
658 | static tree | |
659 | get_function_named_in_call (tree t) | |
660 | { | |
661 | tree fun = cp_get_callee (t); | |
662 | if (fun && TREE_CODE (fun) == ADDR_EXPR | |
663 | && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL) | |
664 | fun = TREE_OPERAND (fun, 0); | |
665 | return fun; | |
666 | } | |
667 | ||
09b42213 | 668 | /* Subroutine of register_constexpr_fundef. BODY is the body of a function |
669 | declared to be constexpr, or a sub-statement thereof. Returns the | |
670 | return value if suitable, error_mark_node for a statement not allowed in | |
671 | a constexpr function, or NULL_TREE if no return value was found. */ | |
672 | ||
c49bd35e | 673 | tree |
09b42213 | 674 | constexpr_fn_retval (tree body) |
675 | { | |
676 | switch (TREE_CODE (body)) | |
677 | { | |
678 | case STATEMENT_LIST: | |
679 | { | |
680 | tree_stmt_iterator i; | |
681 | tree expr = NULL_TREE; | |
682 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
683 | { | |
684 | tree s = constexpr_fn_retval (tsi_stmt (i)); | |
685 | if (s == error_mark_node) | |
686 | return error_mark_node; | |
687 | else if (s == NULL_TREE) | |
688 | /* Keep iterating. */; | |
689 | else if (expr) | |
690 | /* Multiple return statements. */ | |
691 | return error_mark_node; | |
692 | else | |
693 | expr = s; | |
694 | } | |
695 | return expr; | |
696 | } | |
697 | ||
698 | case RETURN_EXPR: | |
699 | return break_out_target_exprs (TREE_OPERAND (body, 0)); | |
700 | ||
701 | case DECL_EXPR: | |
394aed6a | 702 | { |
703 | tree decl = DECL_EXPR_DECL (body); | |
704 | if (TREE_CODE (decl) == USING_DECL | |
705 | /* Accept __func__, __FUNCTION__, and __PRETTY_FUNCTION__. */ | |
706 | || DECL_ARTIFICIAL (decl)) | |
707 | return NULL_TREE; | |
708 | return error_mark_node; | |
709 | } | |
09b42213 | 710 | |
711 | case CLEANUP_POINT_EXPR: | |
712 | return constexpr_fn_retval (TREE_OPERAND (body, 0)); | |
713 | ||
714 | case BIND_EXPR: | |
715 | if (!check_constexpr_bind_expr_vars (body)) | |
716 | return error_mark_node; | |
717 | return constexpr_fn_retval (BIND_EXPR_BODY (body)); | |
718 | ||
719 | case USING_STMT: | |
90567983 | 720 | case DEBUG_BEGIN_STMT: |
09b42213 | 721 | return NULL_TREE; |
722 | ||
2fb20ba2 | 723 | case CALL_EXPR: |
724 | { | |
725 | tree fun = get_function_named_in_call (body); | |
726 | if (fun != NULL_TREE | |
a0e9bfbb | 727 | && fndecl_built_in_p (fun, BUILT_IN_UNREACHABLE)) |
2fb20ba2 | 728 | return NULL_TREE; |
729 | } | |
730 | /* Fallthru. */ | |
731 | ||
09b42213 | 732 | default: |
733 | return error_mark_node; | |
734 | } | |
735 | } | |
736 | ||
737 | /* Subroutine of register_constexpr_fundef. BODY is the DECL_SAVED_TREE of | |
738 | FUN; do the necessary transformations to turn it into a single expression | |
739 | that we can store in the hash table. */ | |
740 | ||
741 | static tree | |
742 | massage_constexpr_body (tree fun, tree body) | |
743 | { | |
744 | if (DECL_CONSTRUCTOR_P (fun)) | |
745 | body = build_constexpr_constructor_member_initializers | |
746 | (DECL_CONTEXT (fun), body); | |
9c96033c | 747 | else if (cxx_dialect < cxx14) |
09b42213 | 748 | { |
749 | if (TREE_CODE (body) == EH_SPEC_BLOCK) | |
750 | body = EH_SPEC_STMTS (body); | |
751 | if (TREE_CODE (body) == MUST_NOT_THROW_EXPR) | |
752 | body = TREE_OPERAND (body, 0); | |
753 | body = constexpr_fn_retval (body); | |
754 | } | |
755 | return body; | |
756 | } | |
757 | ||
2f4cab3c | 758 | /* CTYPE is a type constructed from BODY. Return true if some |
759 | bases/fields are uninitialized, and complain if COMPLAIN. */ | |
09b42213 | 760 | |
761 | static bool | |
2f4cab3c | 762 | cx_check_missing_mem_inits (tree ctype, tree body, bool complain) |
09b42213 | 763 | { |
2f4cab3c | 764 | unsigned nelts = 0; |
765 | ||
766 | if (body) | |
767 | { | |
768 | if (TREE_CODE (body) != CONSTRUCTOR) | |
769 | return false; | |
770 | nelts = CONSTRUCTOR_NELTS (body); | |
771 | } | |
772 | tree field = TYPE_FIELDS (ctype); | |
09b42213 | 773 | |
774 | if (TREE_CODE (ctype) == UNION_TYPE) | |
775 | { | |
776 | if (nelts == 0 && next_initializable_field (field)) | |
777 | { | |
778 | if (complain) | |
779 | error ("%<constexpr%> constructor for union %qT must " | |
780 | "initialize exactly one non-static data member", ctype); | |
781 | return true; | |
782 | } | |
783 | return false; | |
784 | } | |
785 | ||
2f4cab3c | 786 | /* Iterate over the CONSTRUCTOR, checking any missing fields don't |
787 | need an explicit initialization. */ | |
788 | bool bad = false; | |
789 | for (unsigned i = 0; i <= nelts; ++i) | |
09b42213 | 790 | { |
2f4cab3c | 791 | tree index = NULL_TREE; |
792 | if (i < nelts) | |
09b42213 | 793 | { |
794 | index = CONSTRUCTOR_ELT (body, i)->index; | |
795 | /* Skip base and vtable inits. */ | |
796 | if (TREE_CODE (index) != FIELD_DECL | |
797 | || DECL_ARTIFICIAL (index)) | |
798 | continue; | |
799 | } | |
2f4cab3c | 800 | |
09b42213 | 801 | for (; field != index; field = DECL_CHAIN (field)) |
802 | { | |
803 | tree ftype; | |
2f4cab3c | 804 | if (TREE_CODE (field) != FIELD_DECL) |
805 | continue; | |
3cde3c29 | 806 | if (DECL_UNNAMED_BIT_FIELD (field)) |
09b42213 | 807 | continue; |
2f4cab3c | 808 | if (DECL_ARTIFICIAL (field)) |
809 | continue; | |
810 | if (ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
811 | { | |
812 | /* Recurse to check the anonummous aggregate member. */ | |
813 | bad |= cx_check_missing_mem_inits | |
814 | (TREE_TYPE (field), NULL_TREE, complain); | |
815 | if (bad && !complain) | |
816 | return true; | |
817 | continue; | |
818 | } | |
09b42213 | 819 | ftype = strip_array_types (TREE_TYPE (field)); |
820 | if (type_has_constexpr_default_constructor (ftype)) | |
821 | { | |
822 | /* It's OK to skip a member with a trivial constexpr ctor. | |
823 | A constexpr ctor that isn't trivial should have been | |
824 | added in by now. */ | |
825 | gcc_checking_assert (!TYPE_HAS_COMPLEX_DFLT (ftype) | |
826 | || errorcount != 0); | |
827 | continue; | |
828 | } | |
829 | if (!complain) | |
830 | return true; | |
bc35ef65 | 831 | auto_diagnostic_group d; |
859e2c29 | 832 | error ("member %qD must be initialized by mem-initializer " |
833 | "in %<constexpr%> constructor", field); | |
834 | inform (DECL_SOURCE_LOCATION (field), "declared here"); | |
09b42213 | 835 | bad = true; |
836 | } | |
837 | if (field == NULL_TREE) | |
838 | break; | |
2f4cab3c | 839 | |
840 | if (ANON_AGGR_TYPE_P (TREE_TYPE (index))) | |
841 | { | |
842 | /* Check the anonymous aggregate initializer is valid. */ | |
843 | bad |= cx_check_missing_mem_inits | |
844 | (TREE_TYPE (index), CONSTRUCTOR_ELT (body, i)->value, complain); | |
845 | if (bad && !complain) | |
846 | return true; | |
847 | } | |
09b42213 | 848 | field = DECL_CHAIN (field); |
849 | } | |
850 | ||
851 | return bad; | |
852 | } | |
853 | ||
854 | /* We are processing the definition of the constexpr function FUN. | |
855 | Check that its BODY fulfills the propriate requirements and | |
856 | enter it in the constexpr function definition table. | |
857 | For constructor BODY is actually the TREE_LIST of the | |
858 | member-initializer list. */ | |
859 | ||
860 | tree | |
861 | register_constexpr_fundef (tree fun, tree body) | |
862 | { | |
863 | constexpr_fundef entry; | |
864 | constexpr_fundef **slot; | |
865 | ||
866 | if (!is_valid_constexpr_fn (fun, !DECL_GENERATED_P (fun))) | |
867 | return NULL; | |
868 | ||
6a385150 | 869 | tree massaged = massage_constexpr_body (fun, body); |
870 | if (massaged == NULL_TREE || massaged == error_mark_node) | |
09b42213 | 871 | { |
872 | if (!DECL_CONSTRUCTOR_P (fun)) | |
5967b28b | 873 | error ("body of %<constexpr%> function %qD not a return-statement", |
874 | fun); | |
09b42213 | 875 | return NULL; |
876 | } | |
877 | ||
6a385150 | 878 | if (!potential_rvalue_constant_expression (massaged)) |
09b42213 | 879 | { |
880 | if (!DECL_GENERATED_P (fun)) | |
6a385150 | 881 | require_potential_rvalue_constant_expression (massaged); |
09b42213 | 882 | return NULL; |
883 | } | |
884 | ||
885 | if (DECL_CONSTRUCTOR_P (fun) | |
2f4cab3c | 886 | && cx_check_missing_mem_inits (DECL_CONTEXT (fun), |
887 | massaged, !DECL_GENERATED_P (fun))) | |
09b42213 | 888 | return NULL; |
889 | ||
890 | /* Create the constexpr function table if necessary. */ | |
891 | if (constexpr_fundef_table == NULL) | |
892 | constexpr_fundef_table | |
893 | = hash_table<constexpr_fundef_hasher>::create_ggc (101); | |
894 | ||
895 | entry.decl = fun; | |
896 | entry.body = body; | |
897 | slot = constexpr_fundef_table->find_slot (&entry, INSERT); | |
898 | ||
899 | gcc_assert (*slot == NULL); | |
900 | *slot = ggc_alloc<constexpr_fundef> (); | |
901 | **slot = entry; | |
902 | ||
903 | return fun; | |
904 | } | |
905 | ||
906 | /* FUN is a non-constexpr function called in a context that requires a | |
907 | constant expression. If it comes from a constexpr template, explain why | |
908 | the instantiation isn't constexpr. */ | |
909 | ||
910 | void | |
911 | explain_invalid_constexpr_fn (tree fun) | |
912 | { | |
913 | static hash_set<tree> *diagnosed; | |
914 | tree body; | |
915 | location_t save_loc; | |
33603066 | 916 | /* Only diagnose defaulted functions, lambdas, or instantiations. */ |
09b42213 | 917 | if (!DECL_DEFAULTED_FN (fun) |
33603066 | 918 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) |
09b42213 | 919 | && !is_instantiation_of_constexpr (fun)) |
920 | return; | |
921 | if (diagnosed == NULL) | |
922 | diagnosed = new hash_set<tree>; | |
923 | if (diagnosed->add (fun)) | |
924 | /* Already explained. */ | |
925 | return; | |
926 | ||
927 | save_loc = input_location; | |
33603066 | 928 | if (!lambda_static_thunk_p (fun)) |
929 | { | |
930 | /* Diagnostics should completely ignore the static thunk, so leave | |
931 | input_location set to our caller's location. */ | |
932 | input_location = DECL_SOURCE_LOCATION (fun); | |
933 | inform (input_location, | |
5967b28b | 934 | "%qD is not usable as a %<constexpr%> function because:", fun); |
33603066 | 935 | } |
09b42213 | 936 | /* First check the declaration. */ |
937 | if (is_valid_constexpr_fn (fun, true)) | |
938 | { | |
939 | /* Then if it's OK, the body. */ | |
33603066 | 940 | if (!DECL_DECLARED_CONSTEXPR_P (fun) |
941 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun))) | |
09b42213 | 942 | explain_implicit_non_constexpr (fun); |
943 | else | |
944 | { | |
945 | body = massage_constexpr_body (fun, DECL_SAVED_TREE (fun)); | |
946 | require_potential_rvalue_constant_expression (body); | |
947 | if (DECL_CONSTRUCTOR_P (fun)) | |
2f4cab3c | 948 | cx_check_missing_mem_inits (DECL_CONTEXT (fun), body, true); |
09b42213 | 949 | } |
950 | } | |
951 | input_location = save_loc; | |
952 | } | |
953 | ||
954 | /* Objects of this type represent calls to constexpr functions | |
955 | along with the bindings of parameters to their arguments, for | |
956 | the purpose of compile time evaluation. */ | |
957 | ||
958 | struct GTY((for_user)) constexpr_call { | |
959 | /* Description of the constexpr function definition. */ | |
960 | constexpr_fundef *fundef; | |
961 | /* Parameter bindings environment. A TREE_LIST where each TREE_PURPOSE | |
962 | is a parameter _DECL and the TREE_VALUE is the value of the parameter. | |
963 | Note: This arrangement is made to accommodate the use of | |
964 | iterative_hash_template_arg (see pt.c). If you change this | |
965 | representation, also change the hash calculation in | |
966 | cxx_eval_call_expression. */ | |
967 | tree bindings; | |
968 | /* Result of the call. | |
969 | NULL means the call is being evaluated. | |
970 | error_mark_node means that the evaluation was erroneous; | |
971 | otherwise, the actuall value of the call. */ | |
972 | tree result; | |
973 | /* The hash of this call; we remember it here to avoid having to | |
974 | recalculate it when expanding the hash table. */ | |
975 | hashval_t hash; | |
976 | }; | |
977 | ||
b594087e | 978 | struct constexpr_call_hasher : ggc_ptr_hash<constexpr_call> |
09b42213 | 979 | { |
980 | static hashval_t hash (constexpr_call *); | |
981 | static bool equal (constexpr_call *, constexpr_call *); | |
cf72f34d | 982 | }; |
983 | ||
2a2770c6 | 984 | enum constexpr_switch_state { |
985 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
986 | and default: label for that switch has not been seen yet. */ | |
987 | css_default_not_seen, | |
988 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
989 | and default: label for that switch has been seen already. */ | |
990 | css_default_seen, | |
991 | /* Used when processing a switch for the second time by | |
992 | cxx_eval_switch_expr, where default: label should match. */ | |
993 | css_default_processing | |
994 | }; | |
995 | ||
cf72f34d | 996 | /* The constexpr expansion context. CALL is the current function |
997 | expansion, CTOR is the current aggregate initializer, OBJECT is the | |
998 | object being initialized by CTOR, either a VAR_DECL or a _REF. VALUES | |
999 | is a map of values of variables initialized within the expression. */ | |
1000 | ||
1001 | struct constexpr_ctx { | |
f9885b8a | 1002 | /* The innermost call we're evaluating. */ |
cf72f34d | 1003 | constexpr_call *call; |
f9885b8a | 1004 | /* Values for any temporaries or local variables within the |
1005 | constant-expression. */ | |
cf72f34d | 1006 | hash_map<tree,tree> *values; |
2631cb67 | 1007 | /* SAVE_EXPRs that we've seen within the current LOOP_EXPR. NULL if we |
1008 | aren't inside a loop. */ | |
1009 | hash_set<tree> *save_exprs; | |
f9885b8a | 1010 | /* The CONSTRUCTOR we're currently building up for an aggregate |
1011 | initializer. */ | |
cf72f34d | 1012 | tree ctor; |
f9885b8a | 1013 | /* The object we're building the CONSTRUCTOR for. */ |
cf72f34d | 1014 | tree object; |
2a2770c6 | 1015 | /* If inside SWITCH_EXPR. */ |
1016 | constexpr_switch_state *css_state; | |
f9885b8a | 1017 | /* Whether we should error on a non-constant expression or fail quietly. */ |
f83e6885 | 1018 | bool quiet; |
f9885b8a | 1019 | /* Whether we are strictly conforming to constant expression rules or |
1020 | trying harder to get a constant value. */ | |
2055d27a | 1021 | bool strict; |
18d371d3 | 1022 | /* Whether __builtin_is_constant_evaluated () should be true. */ |
1023 | bool pretend_const_required; | |
cf72f34d | 1024 | }; |
09b42213 | 1025 | |
1026 | /* A table of all constexpr calls that have been evaluated by the | |
1027 | compiler in this translation unit. */ | |
1028 | ||
a050099a | 1029 | static GTY (()) hash_table<constexpr_call_hasher> *constexpr_call_table; |
09b42213 | 1030 | |
cf72f34d | 1031 | static tree cxx_eval_constant_expression (const constexpr_ctx *, tree, |
b2a43197 | 1032 | bool, bool *, bool *, tree * = NULL); |
09b42213 | 1033 | |
1034 | /* Compute a hash value for a constexpr call representation. */ | |
1035 | ||
1036 | inline hashval_t | |
1037 | constexpr_call_hasher::hash (constexpr_call *info) | |
1038 | { | |
1039 | return info->hash; | |
1040 | } | |
1041 | ||
1042 | /* Return true if the objects pointed to by P and Q represent calls | |
1043 | to the same constexpr function with the same arguments. | |
1044 | Otherwise, return false. */ | |
1045 | ||
1046 | bool | |
1047 | constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs) | |
1048 | { | |
1049 | tree lhs_bindings; | |
1050 | tree rhs_bindings; | |
1051 | if (lhs == rhs) | |
c751e2cd | 1052 | return true; |
1053 | if (lhs->hash != rhs->hash) | |
1054 | return false; | |
09b42213 | 1055 | if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef)) |
c751e2cd | 1056 | return false; |
09b42213 | 1057 | lhs_bindings = lhs->bindings; |
1058 | rhs_bindings = rhs->bindings; | |
1059 | while (lhs_bindings != NULL && rhs_bindings != NULL) | |
1060 | { | |
1061 | tree lhs_arg = TREE_VALUE (lhs_bindings); | |
1062 | tree rhs_arg = TREE_VALUE (rhs_bindings); | |
6d82dbcd | 1063 | gcc_assert (same_type_p (TREE_TYPE (lhs_arg), TREE_TYPE (rhs_arg))); |
09b42213 | 1064 | if (!cp_tree_equal (lhs_arg, rhs_arg)) |
c751e2cd | 1065 | return false; |
09b42213 | 1066 | lhs_bindings = TREE_CHAIN (lhs_bindings); |
1067 | rhs_bindings = TREE_CHAIN (rhs_bindings); | |
1068 | } | |
1069 | return lhs_bindings == rhs_bindings; | |
1070 | } | |
1071 | ||
1072 | /* Initialize the constexpr call table, if needed. */ | |
1073 | ||
1074 | static void | |
1075 | maybe_initialize_constexpr_call_table (void) | |
1076 | { | |
1077 | if (constexpr_call_table == NULL) | |
1078 | constexpr_call_table = hash_table<constexpr_call_hasher>::create_ggc (101); | |
1079 | } | |
1080 | ||
4f7ebe46 | 1081 | /* During constexpr CALL_EXPR evaluation, to avoid issues with sharing when |
1082 | a function happens to get called recursively, we unshare the callee | |
1083 | function's body and evaluate this unshared copy instead of evaluating the | |
1084 | original body. | |
1085 | ||
1086 | FUNDEF_COPIES_TABLE is a per-function freelist of these unshared function | |
1087 | copies. The underlying data structure of FUNDEF_COPIES_TABLE is a hash_map | |
a050099a | 1088 | that's keyed off of the original FUNCTION_DECL and whose value is a |
1089 | TREE_LIST of this function's unused copies awaiting reuse. | |
4f7ebe46 | 1090 | |
a050099a | 1091 | This is not GC-deletable to avoid GC affecting UID generation. */ |
4f7ebe46 | 1092 | |
a050099a | 1093 | static GTY(()) hash_map<tree, tree> *fundef_copies_table; |
4f7ebe46 | 1094 | |
1095 | /* Initialize FUNDEF_COPIES_TABLE if it's not initialized. */ | |
1096 | ||
1097 | static void | |
1098 | maybe_initialize_fundef_copies_table () | |
1099 | { | |
a050099a | 1100 | if (fundef_copies_table == NULL) |
1101 | fundef_copies_table = hash_map<tree,tree>::create_ggc (101); | |
4f7ebe46 | 1102 | } |
1103 | ||
1104 | /* Reuse a copy or create a new unshared copy of the function FUN. | |
886d5463 | 1105 | Return this copy. We use a TREE_LIST whose PURPOSE is body, VALUE |
1106 | is parms, TYPE is result. */ | |
4f7ebe46 | 1107 | |
a050099a | 1108 | static tree |
4f7ebe46 | 1109 | get_fundef_copy (tree fun) |
1110 | { | |
1111 | maybe_initialize_fundef_copies_table (); | |
1112 | ||
a050099a | 1113 | tree copy; |
886d5463 | 1114 | bool existed; |
1115 | tree *slot = &fundef_copies_table->get_or_insert (fun, &existed); | |
1116 | ||
1117 | if (!existed) | |
4f7ebe46 | 1118 | { |
886d5463 | 1119 | /* There is no cached function available, or in use. We can use |
1120 | the function directly. That the slot is now created records | |
1121 | that this function is now in use. */ | |
1122 | copy = build_tree_list (DECL_SAVED_TREE (fun), DECL_ARGUMENTS (fun)); | |
1123 | TREE_TYPE (copy) = DECL_RESULT (fun); | |
1124 | } | |
1125 | else if (*slot == NULL_TREE) | |
1126 | { | |
1127 | /* We've already used the function itself, so make a copy. */ | |
a050099a | 1128 | copy = build_tree_list (NULL, NULL); |
a050099a | 1129 | TREE_PURPOSE (copy) = copy_fn (fun, TREE_VALUE (copy), TREE_TYPE (copy)); |
4f7ebe46 | 1130 | } |
1131 | else | |
1132 | { | |
886d5463 | 1133 | /* We have a cached function available. */ |
4f7ebe46 | 1134 | copy = *slot; |
a050099a | 1135 | *slot = TREE_CHAIN (copy); |
4f7ebe46 | 1136 | } |
1137 | ||
1138 | return copy; | |
1139 | } | |
1140 | ||
886d5463 | 1141 | /* Save the copy COPY of function FUN for later reuse by |
1142 | get_fundef_copy(). By construction, there will always be an entry | |
1143 | to find. */ | |
4f7ebe46 | 1144 | |
1145 | static void | |
a050099a | 1146 | save_fundef_copy (tree fun, tree copy) |
4f7ebe46 | 1147 | { |
886d5463 | 1148 | tree *slot = fundef_copies_table->get (fun); |
a050099a | 1149 | TREE_CHAIN (copy) = *slot; |
4f7ebe46 | 1150 | *slot = copy; |
1151 | } | |
1152 | ||
09b42213 | 1153 | /* We have an expression tree T that represents a call, either CALL_EXPR |
1154 | or AGGR_INIT_EXPR. Return the Nth argument. */ | |
1155 | ||
1156 | static inline tree | |
1157 | get_nth_callarg (tree t, int n) | |
1158 | { | |
1159 | switch (TREE_CODE (t)) | |
1160 | { | |
1161 | case CALL_EXPR: | |
1162 | return CALL_EXPR_ARG (t, n); | |
1163 | ||
1164 | case AGGR_INIT_EXPR: | |
1165 | return AGGR_INIT_EXPR_ARG (t, n); | |
1166 | ||
1167 | default: | |
1168 | gcc_unreachable (); | |
1169 | return NULL; | |
1170 | } | |
1171 | } | |
1172 | ||
09b42213 | 1173 | /* Attempt to evaluate T which represents a call to a builtin function. |
1174 | We assume here that all builtin functions evaluate to scalar types | |
1175 | represented by _CST nodes. */ | |
1176 | ||
1177 | static tree | |
f1c6af10 | 1178 | cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, |
1227ba74 | 1179 | bool lval, |
09b42213 | 1180 | bool *non_constant_p, bool *overflow_p) |
1181 | { | |
1182 | const int nargs = call_expr_nargs (t); | |
1183 | tree *args = (tree *) alloca (nargs * sizeof (tree)); | |
1184 | tree new_call; | |
1185 | int i; | |
f1c6af10 | 1186 | |
1187 | /* Don't fold __builtin_constant_p within a constexpr function. */ | |
18d371d3 | 1188 | bool bi_const_p = DECL_IS_BUILTIN_CONSTANT_P (fun); |
efe6a40a | 1189 | |
0f5cec54 | 1190 | /* If we aren't requiring a constant expression, defer __builtin_constant_p |
1191 | in a constexpr function until we have values for the parameters. */ | |
efe6a40a | 1192 | if (bi_const_p |
0f5cec54 | 1193 | && ctx->quiet |
f1c6af10 | 1194 | && current_function_decl |
1195 | && DECL_DECLARED_CONSTEXPR_P (current_function_decl)) | |
09b42213 | 1196 | { |
f1c6af10 | 1197 | *non_constant_p = true; |
1198 | return t; | |
09b42213 | 1199 | } |
f1c6af10 | 1200 | |
18d371d3 | 1201 | /* For __builtin_is_constant_evaluated, defer it if not |
1202 | ctx->pretend_const_required, otherwise fold it to true. */ | |
a0e9bfbb | 1203 | if (fndecl_built_in_p (fun, CP_BUILT_IN_IS_CONSTANT_EVALUATED, |
1204 | BUILT_IN_FRONTEND)) | |
18d371d3 | 1205 | { |
1206 | if (!ctx->pretend_const_required) | |
1207 | { | |
1208 | *non_constant_p = true; | |
1209 | return t; | |
1210 | } | |
1211 | return boolean_true_node; | |
1212 | } | |
1213 | ||
f1c6af10 | 1214 | /* Be permissive for arguments to built-ins; __builtin_constant_p should |
1215 | return constant false for a non-constant argument. */ | |
1216 | constexpr_ctx new_ctx = *ctx; | |
1217 | new_ctx.quiet = true; | |
1218 | bool dummy1 = false, dummy2 = false; | |
1219 | for (i = 0; i < nargs; ++i) | |
efe6a40a | 1220 | { |
91b66c3c | 1221 | args[i] = CALL_EXPR_ARG (t, i); |
1222 | /* If builtin_valid_in_constant_expr_p is true, | |
1223 | potential_constant_expression_1 has not recursed into the arguments | |
1224 | of the builtin, verify it here. */ | |
1225 | if (!builtin_valid_in_constant_expr_p (fun) | |
1226 | || potential_constant_expression (args[i])) | |
1227 | args[i] = cxx_eval_constant_expression (&new_ctx, args[i], false, | |
1228 | &dummy1, &dummy2); | |
efe6a40a | 1229 | if (bi_const_p) |
1230 | /* For __built_in_constant_p, fold all expressions with constant values | |
1231 | even if they aren't C++ constant-expressions. */ | |
1232 | args[i] = cp_fully_fold (args[i]); | |
1233 | } | |
f1c6af10 | 1234 | |
1235 | bool save_ffbcp = force_folding_builtin_constant_p; | |
1236 | force_folding_builtin_constant_p = true; | |
051eb924 | 1237 | new_call = fold_builtin_call_array (EXPR_LOCATION (t), TREE_TYPE (t), |
1238 | CALL_EXPR_FN (t), nargs, args); | |
f1c6af10 | 1239 | force_folding_builtin_constant_p = save_ffbcp; |
051eb924 | 1240 | if (new_call == NULL) |
1241 | { | |
1242 | if (!*non_constant_p && !ctx->quiet) | |
1243 | { | |
2fb20ba2 | 1244 | /* Do not allow__builtin_unreachable in constexpr function. |
1245 | The __builtin_unreachable call with BUILTINS_LOCATION | |
1246 | comes from cp_maybe_instrument_return. */ | |
a0e9bfbb | 1247 | if (fndecl_built_in_p (fun, BUILT_IN_UNREACHABLE) |
2fb20ba2 | 1248 | && EXPR_LOCATION (t) == BUILTINS_LOCATION) |
5967b28b | 1249 | error ("%<constexpr%> call flows off the end of the function"); |
2fb20ba2 | 1250 | else |
1251 | { | |
1252 | new_call = build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t), | |
1253 | CALL_EXPR_FN (t), nargs, args); | |
1254 | error ("%q+E is not a constant expression", new_call); | |
1255 | } | |
051eb924 | 1256 | } |
1257 | *non_constant_p = true; | |
1258 | return t; | |
1259 | } | |
1260 | ||
7e1f8be4 | 1261 | if (!is_constant_expression (new_call)) |
051eb924 | 1262 | { |
1263 | if (!*non_constant_p && !ctx->quiet) | |
1264 | error ("%q+E is not a constant expression", new_call); | |
1265 | *non_constant_p = true; | |
1266 | return t; | |
1267 | } | |
1268 | ||
1269 | return cxx_eval_constant_expression (&new_ctx, new_call, lval, | |
1270 | non_constant_p, overflow_p); | |
09b42213 | 1271 | } |
1272 | ||
1273 | /* TEMP is the constant value of a temporary object of type TYPE. Adjust | |
1274 | the type of the value to match. */ | |
1275 | ||
1276 | static tree | |
1277 | adjust_temp_type (tree type, tree temp) | |
1278 | { | |
6d82dbcd | 1279 | if (same_type_p (TREE_TYPE (temp), type)) |
09b42213 | 1280 | return temp; |
1281 | /* Avoid wrapping an aggregate value in a NOP_EXPR. */ | |
1282 | if (TREE_CODE (temp) == CONSTRUCTOR) | |
1283 | return build_constructor (type, CONSTRUCTOR_ELTS (temp)); | |
1284 | gcc_assert (scalarish_type_p (type)); | |
1285 | return cp_fold_convert (type, temp); | |
1286 | } | |
1287 | ||
e283bb4f | 1288 | /* Callback for walk_tree used by unshare_constructor. */ |
1289 | ||
1290 | static tree | |
1291 | find_constructor (tree *tp, int *walk_subtrees, void *) | |
1292 | { | |
1293 | if (TYPE_P (*tp)) | |
1294 | *walk_subtrees = 0; | |
1295 | if (TREE_CODE (*tp) == CONSTRUCTOR) | |
1296 | return *tp; | |
1297 | return NULL_TREE; | |
1298 | } | |
1299 | ||
1300 | /* If T is a CONSTRUCTOR or an expression that has a CONSTRUCTOR node as a | |
1301 | subexpression, return an unshared copy of T. Otherwise return T. */ | |
1302 | ||
1303 | static tree | |
1304 | unshare_constructor (tree t) | |
1305 | { | |
1306 | tree ctor = walk_tree (&t, find_constructor, NULL, NULL); | |
1307 | if (ctor != NULL_TREE) | |
1308 | return unshare_expr (t); | |
1309 | return t; | |
1310 | } | |
1311 | ||
09b42213 | 1312 | /* Subroutine of cxx_eval_call_expression. |
1313 | We are processing a call expression (either CALL_EXPR or | |
cf72f34d | 1314 | AGGR_INIT_EXPR) in the context of CTX. Evaluate |
09b42213 | 1315 | all arguments and bind their values to correspondings |
1316 | parameters, making up the NEW_CALL context. */ | |
1317 | ||
1318 | static void | |
cf72f34d | 1319 | cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, |
09b42213 | 1320 | constexpr_call *new_call, |
c8f6aeb1 | 1321 | bool *non_constant_p, bool *overflow_p, |
1322 | bool *non_constant_args) | |
09b42213 | 1323 | { |
1324 | const int nargs = call_expr_nargs (t); | |
1325 | tree fun = new_call->fundef->decl; | |
1326 | tree parms = DECL_ARGUMENTS (fun); | |
1327 | int i; | |
9c96033c | 1328 | tree *p = &new_call->bindings; |
09b42213 | 1329 | for (i = 0; i < nargs; ++i) |
1330 | { | |
1331 | tree x, arg; | |
1332 | tree type = parms ? TREE_TYPE (parms) : void_type_node; | |
09b42213 | 1333 | x = get_nth_callarg (t, i); |
cf72f34d | 1334 | /* For member function, the first argument is a pointer to the implied |
1335 | object. For a constructor, it might still be a dummy object, in | |
9c96033c | 1336 | which case we get the real argument from ctx. */ |
cf72f34d | 1337 | if (i == 0 && DECL_CONSTRUCTOR_P (fun) |
1338 | && is_dummy_object (x)) | |
1339 | { | |
1340 | x = ctx->object; | |
c017458d | 1341 | x = build_address (x); |
cf72f34d | 1342 | } |
2e1c71c2 | 1343 | arg = cxx_eval_constant_expression (ctx, x, /*lval=*/false, |
b2a43197 | 1344 | non_constant_p, overflow_p); |
09b42213 | 1345 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 1346 | if (*non_constant_p && ctx->quiet) |
09b42213 | 1347 | return; |
1348 | /* Just discard ellipsis args after checking their constantitude. */ | |
1349 | if (!parms) | |
1350 | continue; | |
2ba934c7 | 1351 | |
1352 | if (!*non_constant_p) | |
1353 | { | |
24d5b4f0 | 1354 | /* Don't share a CONSTRUCTOR that might be changed. */ |
1355 | arg = unshare_constructor (arg); | |
2ba934c7 | 1356 | /* Make sure the binding has the same type as the parm. But |
1357 | only for constant args. */ | |
90ad495b | 1358 | if (!TYPE_REF_P (type)) |
2ba934c7 | 1359 | arg = adjust_temp_type (type, arg); |
1360 | if (!TREE_CONSTANT (arg)) | |
1361 | *non_constant_args = true; | |
1362 | *p = build_tree_list (parms, arg); | |
1363 | p = &TREE_CHAIN (*p); | |
1364 | } | |
09b42213 | 1365 | parms = TREE_CHAIN (parms); |
1366 | } | |
1367 | } | |
1368 | ||
1369 | /* Variables and functions to manage constexpr call expansion context. | |
1370 | These do not need to be marked for PCH or GC. */ | |
1371 | ||
1372 | /* FIXME remember and print actual constant arguments. */ | |
16fb756f | 1373 | static vec<tree> call_stack; |
09b42213 | 1374 | static int call_stack_tick; |
1375 | static int last_cx_error_tick; | |
1376 | ||
1377 | static bool | |
1378 | push_cx_call_context (tree call) | |
1379 | { | |
1380 | ++call_stack_tick; | |
1381 | if (!EXPR_HAS_LOCATION (call)) | |
1382 | SET_EXPR_LOCATION (call, input_location); | |
1383 | call_stack.safe_push (call); | |
1384 | if (call_stack.length () > (unsigned) max_constexpr_depth) | |
1385 | return false; | |
1386 | return true; | |
1387 | } | |
1388 | ||
1389 | static void | |
1390 | pop_cx_call_context (void) | |
1391 | { | |
1392 | ++call_stack_tick; | |
1393 | call_stack.pop (); | |
1394 | } | |
1395 | ||
1396 | vec<tree> | |
1397 | cx_error_context (void) | |
1398 | { | |
1399 | vec<tree> r = vNULL; | |
1400 | if (call_stack_tick != last_cx_error_tick | |
1401 | && !call_stack.is_empty ()) | |
1402 | r = call_stack; | |
1403 | last_cx_error_tick = call_stack_tick; | |
1404 | return r; | |
1405 | } | |
1406 | ||
732905bb | 1407 | /* Evaluate a call T to a GCC internal function when possible and return |
1408 | the evaluated result or, under the control of CTX, give an error, set | |
1409 | NON_CONSTANT_P, and return the unevaluated call T otherwise. */ | |
1410 | ||
1411 | static tree | |
1412 | cxx_eval_internal_function (const constexpr_ctx *ctx, tree t, | |
1413 | bool lval, | |
1414 | bool *non_constant_p, bool *overflow_p) | |
1415 | { | |
1416 | enum tree_code opcode = ERROR_MARK; | |
1417 | ||
1418 | switch (CALL_EXPR_IFN (t)) | |
1419 | { | |
1420 | case IFN_UBSAN_NULL: | |
1421 | case IFN_UBSAN_BOUNDS: | |
1422 | case IFN_UBSAN_VPTR: | |
3c77f69c | 1423 | case IFN_FALLTHROUGH: |
732905bb | 1424 | return void_node; |
1425 | ||
1426 | case IFN_ADD_OVERFLOW: | |
1427 | opcode = PLUS_EXPR; | |
1428 | break; | |
1429 | case IFN_SUB_OVERFLOW: | |
1430 | opcode = MINUS_EXPR; | |
1431 | break; | |
1432 | case IFN_MUL_OVERFLOW: | |
1433 | opcode = MULT_EXPR; | |
1434 | break; | |
1435 | ||
6e1b2ffb | 1436 | case IFN_LAUNDER: |
1437 | return cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), | |
1438 | false, non_constant_p, overflow_p); | |
1439 | ||
732905bb | 1440 | default: |
1441 | if (!ctx->quiet) | |
d3a3cfb8 | 1442 | error_at (cp_expr_loc_or_loc (t, input_location), |
732905bb | 1443 | "call to internal function %qE", t); |
1444 | *non_constant_p = true; | |
1445 | return t; | |
1446 | } | |
1447 | ||
1448 | /* Evaluate constant arguments using OPCODE and return a complex | |
1449 | number containing the result and the overflow bit. */ | |
1450 | tree arg0 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), lval, | |
1451 | non_constant_p, overflow_p); | |
1452 | tree arg1 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 1), lval, | |
1453 | non_constant_p, overflow_p); | |
1454 | ||
1455 | if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) | |
1456 | { | |
d3a3cfb8 | 1457 | location_t loc = cp_expr_loc_or_loc (t, input_location); |
732905bb | 1458 | tree type = TREE_TYPE (TREE_TYPE (t)); |
1459 | tree result = fold_binary_loc (loc, opcode, type, | |
1460 | fold_convert_loc (loc, type, arg0), | |
1461 | fold_convert_loc (loc, type, arg1)); | |
1462 | tree ovf | |
1463 | = build_int_cst (type, arith_overflowed_p (opcode, type, arg0, arg1)); | |
1464 | /* Reset TREE_OVERFLOW to avoid warnings for the overflow. */ | |
1465 | if (TREE_OVERFLOW (result)) | |
1466 | TREE_OVERFLOW (result) = 0; | |
1467 | ||
1468 | return build_complex (TREE_TYPE (t), result, ovf); | |
1469 | } | |
1470 | ||
1471 | *non_constant_p = true; | |
1472 | return t; | |
1473 | } | |
1474 | ||
165d0d5b | 1475 | /* Clean CONSTRUCTOR_NO_CLEARING from CTOR and its sub-aggregates. */ |
79cdb4f5 | 1476 | |
1477 | static void | |
1478 | clear_no_implicit_zero (tree ctor) | |
1479 | { | |
165d0d5b | 1480 | if (CONSTRUCTOR_NO_CLEARING (ctor)) |
79cdb4f5 | 1481 | { |
165d0d5b | 1482 | CONSTRUCTOR_NO_CLEARING (ctor) = false; |
79cdb4f5 | 1483 | tree elt; unsigned HOST_WIDE_INT idx; |
1484 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (ctor), idx, elt) | |
1485 | if (TREE_CODE (elt) == CONSTRUCTOR) | |
1486 | clear_no_implicit_zero (elt); | |
1487 | } | |
1488 | } | |
1489 | ||
09b42213 | 1490 | /* Subroutine of cxx_eval_constant_expression. |
1491 | Evaluate the call expression tree T in the context of OLD_CALL expression | |
1492 | evaluation. */ | |
1493 | ||
1494 | static tree | |
cf72f34d | 1495 | cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1496 | bool lval, |
09b42213 | 1497 | bool *non_constant_p, bool *overflow_p) |
1498 | { | |
d3a3cfb8 | 1499 | location_t loc = cp_expr_loc_or_loc (t, input_location); |
09b42213 | 1500 | tree fun = get_function_named_in_call (t); |
09b42213 | 1501 | constexpr_call new_call = { NULL, NULL, NULL, 0 }; |
09b42213 | 1502 | bool depth_ok; |
1503 | ||
6b71bdb4 | 1504 | if (fun == NULL_TREE) |
732905bb | 1505 | return cxx_eval_internal_function (ctx, t, lval, |
1506 | non_constant_p, overflow_p); | |
6b71bdb4 | 1507 | |
09b42213 | 1508 | if (TREE_CODE (fun) != FUNCTION_DECL) |
1509 | { | |
1510 | /* Might be a constexpr function pointer. */ | |
f83e6885 | 1511 | fun = cxx_eval_constant_expression (ctx, fun, |
1227ba74 | 1512 | /*lval*/false, non_constant_p, |
b2a43197 | 1513 | overflow_p); |
09b42213 | 1514 | STRIP_NOPS (fun); |
1515 | if (TREE_CODE (fun) == ADDR_EXPR) | |
1516 | fun = TREE_OPERAND (fun, 0); | |
1517 | } | |
1518 | if (TREE_CODE (fun) != FUNCTION_DECL) | |
1519 | { | |
f83e6885 | 1520 | if (!ctx->quiet && !*non_constant_p) |
5967b28b | 1521 | error_at (loc, "expression %qE does not designate a %<constexpr%> " |
09b42213 | 1522 | "function", fun); |
1523 | *non_constant_p = true; | |
1524 | return t; | |
1525 | } | |
1526 | if (DECL_CLONED_FUNCTION_P (fun)) | |
1527 | fun = DECL_CLONED_FUNCTION (fun); | |
6b71bdb4 | 1528 | |
1529 | if (is_ubsan_builtin_p (fun)) | |
1530 | return void_node; | |
1531 | ||
a0e9bfbb | 1532 | if (fndecl_built_in_p (fun)) |
f1c6af10 | 1533 | return cxx_eval_builtin_function_call (ctx, t, fun, |
1227ba74 | 1534 | lval, non_constant_p, overflow_p); |
09b42213 | 1535 | if (!DECL_DECLARED_CONSTEXPR_P (fun)) |
1536 | { | |
f83e6885 | 1537 | if (!ctx->quiet) |
09b42213 | 1538 | { |
1dcd84cf | 1539 | if (!lambda_static_thunk_p (fun)) |
5967b28b | 1540 | error_at (loc, "call to non-%<constexpr%> function %qD", fun); |
09b42213 | 1541 | explain_invalid_constexpr_fn (fun); |
1542 | } | |
1543 | *non_constant_p = true; | |
1544 | return t; | |
1545 | } | |
1546 | ||
9ebe2ea3 | 1547 | constexpr_ctx new_ctx = *ctx; |
1548 | if (DECL_CONSTRUCTOR_P (fun) && !ctx->object | |
1549 | && TREE_CODE (t) == AGGR_INIT_EXPR) | |
1550 | { | |
1551 | /* We want to have an initialization target for an AGGR_INIT_EXPR. | |
1552 | If we don't already have one in CTX, use the AGGR_INIT_EXPR_SLOT. */ | |
1553 | new_ctx.object = AGGR_INIT_EXPR_SLOT (t); | |
1554 | tree ctor = new_ctx.ctor = build_constructor (DECL_CONTEXT (fun), NULL); | |
165d0d5b | 1555 | CONSTRUCTOR_NO_CLEARING (ctor) = true; |
9ebe2ea3 | 1556 | ctx->values->put (new_ctx.object, ctor); |
1557 | ctx = &new_ctx; | |
1558 | } | |
1559 | ||
09b42213 | 1560 | /* Shortcut trivial constructor/op=. */ |
1561 | if (trivial_fn_p (fun)) | |
1562 | { | |
9ebe2ea3 | 1563 | tree init = NULL_TREE; |
09b42213 | 1564 | if (call_expr_nargs (t) == 2) |
9ebe2ea3 | 1565 | init = convert_from_reference (get_nth_callarg (t, 1)); |
09b42213 | 1566 | else if (TREE_CODE (t) == AGGR_INIT_EXPR |
1567 | && AGGR_INIT_ZERO_FIRST (t)) | |
9ebe2ea3 | 1568 | init = build_zero_init (DECL_CONTEXT (fun), NULL_TREE, false); |
1569 | if (init) | |
1570 | { | |
1571 | tree op = get_nth_callarg (t, 0); | |
1572 | if (is_dummy_object (op)) | |
1573 | op = ctx->object; | |
1574 | else | |
1575 | op = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (op)), op); | |
1576 | tree set = build2 (MODIFY_EXPR, TREE_TYPE (op), op, init); | |
0ce12360 | 1577 | new_ctx.call = &new_call; |
1578 | return cxx_eval_constant_expression (&new_ctx, set, lval, | |
9ebe2ea3 | 1579 | non_constant_p, overflow_p); |
1580 | } | |
09b42213 | 1581 | } |
1582 | ||
8afcf831 | 1583 | /* We can't defer instantiating the function any longer. */ |
1584 | if (!DECL_INITIAL (fun) | |
1585 | && DECL_TEMPLOID_INSTANTIATION (fun)) | |
1586 | { | |
31db86df | 1587 | location_t save_loc = input_location; |
1588 | input_location = loc; | |
8afcf831 | 1589 | ++function_depth; |
1590 | instantiate_decl (fun, /*defer_ok*/false, /*expl_inst*/false); | |
1591 | --function_depth; | |
31db86df | 1592 | input_location = save_loc; |
8afcf831 | 1593 | } |
1594 | ||
09b42213 | 1595 | /* If in direct recursive call, optimize definition search. */ |
0ce12360 | 1596 | if (ctx && ctx->call && ctx->call->fundef && ctx->call->fundef->decl == fun) |
cf72f34d | 1597 | new_call.fundef = ctx->call->fundef; |
09b42213 | 1598 | else |
1599 | { | |
1600 | new_call.fundef = retrieve_constexpr_fundef (fun); | |
d2a9b1c1 | 1601 | if (new_call.fundef == NULL || new_call.fundef->body == NULL |
1602 | || fun == current_function_decl) | |
09b42213 | 1603 | { |
f83e6885 | 1604 | if (!ctx->quiet) |
09b42213 | 1605 | { |
d2a9b1c1 | 1606 | /* We need to check for current_function_decl here in case we're |
1607 | being called during cp_fold_function, because at that point | |
1608 | DECL_INITIAL is set properly and we have a fundef but we | |
1609 | haven't lowered invisirefs yet (c++/70344). */ | |
1610 | if (DECL_INITIAL (fun) == error_mark_node | |
1611 | || fun == current_function_decl) | |
a0efa758 | 1612 | error_at (loc, "%qD called in a constant expression before its " |
1613 | "definition is complete", fun); | |
1614 | else if (DECL_INITIAL (fun)) | |
09b42213 | 1615 | { |
33603066 | 1616 | /* The definition of fun was somehow unsuitable. But pretend |
1617 | that lambda static thunks don't exist. */ | |
1618 | if (!lambda_static_thunk_p (fun)) | |
1619 | error_at (loc, "%qD called in a constant expression", fun); | |
09b42213 | 1620 | explain_invalid_constexpr_fn (fun); |
1621 | } | |
1622 | else | |
1623 | error_at (loc, "%qD used before its definition", fun); | |
1624 | } | |
1625 | *non_constant_p = true; | |
1626 | return t; | |
1627 | } | |
1628 | } | |
9c96033c | 1629 | |
c8f6aeb1 | 1630 | bool non_constant_args = false; |
cf72f34d | 1631 | cxx_bind_parameters_in_call (ctx, t, &new_call, |
c8f6aeb1 | 1632 | non_constant_p, overflow_p, &non_constant_args); |
09b42213 | 1633 | if (*non_constant_p) |
1634 | return t; | |
1635 | ||
1636 | depth_ok = push_cx_call_context (t); | |
1637 | ||
c8f6aeb1 | 1638 | tree result = NULL_TREE; |
09b42213 | 1639 | |
c8f6aeb1 | 1640 | constexpr_call *entry = NULL; |
167a09fb | 1641 | if (depth_ok && !non_constant_args && ctx->strict) |
09b42213 | 1642 | { |
c8f6aeb1 | 1643 | new_call.hash = iterative_hash_template_arg |
1644 | (new_call.bindings, constexpr_fundef_hasher::hash (new_call.fundef)); | |
1645 | ||
1646 | /* If we have seen this call before, we are done. */ | |
1647 | maybe_initialize_constexpr_call_table (); | |
1648 | constexpr_call **slot | |
1649 | = constexpr_call_table->find_slot (&new_call, INSERT); | |
1650 | entry = *slot; | |
1651 | if (entry == NULL) | |
1652 | { | |
1653 | /* We need to keep a pointer to the entry, not just the slot, as the | |
1654 | slot can move in the call to cxx_eval_builtin_function_call. */ | |
1655 | *slot = entry = ggc_alloc<constexpr_call> (); | |
1656 | *entry = new_call; | |
1657 | } | |
2ba934c7 | 1658 | /* Calls that are in progress have their result set to NULL, |
c8f6aeb1 | 1659 | so that we can detect circular dependencies. */ |
1660 | else if (entry->result == NULL) | |
1661 | { | |
1662 | if (!ctx->quiet) | |
1663 | error ("call has circular dependency"); | |
1664 | *non_constant_p = true; | |
1665 | entry->result = result = error_mark_node; | |
1666 | } | |
1667 | else | |
1668 | result = entry->result; | |
09b42213 | 1669 | } |
1670 | ||
1671 | if (!depth_ok) | |
1672 | { | |
f83e6885 | 1673 | if (!ctx->quiet) |
5967b28b | 1674 | error ("%<constexpr%> evaluation depth exceeds maximum of %d (use " |
f91d3a9d | 1675 | "%<-fconstexpr-depth=%> to increase the maximum)", |
09b42213 | 1676 | max_constexpr_depth); |
1677 | *non_constant_p = true; | |
c8f6aeb1 | 1678 | result = error_mark_node; |
09b42213 | 1679 | } |
1680 | else | |
1681 | { | |
ab099088 | 1682 | if (result && result != error_mark_node) |
1683 | /* OK */; | |
1684 | else if (!DECL_SAVED_TREE (fun)) | |
1685 | { | |
1686 | /* When at_eof >= 2, cgraph has started throwing away | |
1687 | DECL_SAVED_TREE, so fail quietly. FIXME we get here because of | |
1688 | late code generation for VEC_INIT_EXPR, which needs to be | |
1689 | completely reconsidered. */ | |
1690 | gcc_assert (at_eof >= 2 && ctx->quiet); | |
1691 | *non_constant_p = true; | |
1692 | } | |
1693 | else | |
cf72f34d | 1694 | { |
4f7ebe46 | 1695 | tree body, parms, res; |
88a59139 | 1696 | |
4f7ebe46 | 1697 | /* Reuse or create a new unshared copy of this function's body. */ |
a050099a | 1698 | tree copy = get_fundef_copy (fun); |
1699 | body = TREE_PURPOSE (copy); | |
1700 | parms = TREE_VALUE (copy); | |
1701 | res = TREE_TYPE (copy); | |
88a59139 | 1702 | |
1703 | /* Associate the bindings with the remapped parms. */ | |
1704 | tree bound = new_call.bindings; | |
1705 | tree remapped = parms; | |
1706 | while (bound) | |
9c96033c | 1707 | { |
88a59139 | 1708 | tree oparm = TREE_PURPOSE (bound); |
1709 | tree arg = TREE_VALUE (bound); | |
1710 | gcc_assert (DECL_NAME (remapped) == DECL_NAME (oparm)); | |
5898f0d7 | 1711 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 1712 | arg = unshare_constructor (arg); |
88a59139 | 1713 | ctx->values->put (remapped, arg); |
1714 | bound = TREE_CHAIN (bound); | |
1715 | remapped = DECL_CHAIN (remapped); | |
9c96033c | 1716 | } |
88a59139 | 1717 | /* Add the RESULT_DECL to the values map, too. */ |
1718 | tree slot = NULL_TREE; | |
1719 | if (DECL_BY_REFERENCE (res)) | |
9c96033c | 1720 | { |
88a59139 | 1721 | slot = AGGR_INIT_EXPR_SLOT (t); |
1722 | tree addr = build_address (slot); | |
1723 | addr = build_nop (TREE_TYPE (res), addr); | |
1724 | ctx->values->put (res, addr); | |
1725 | ctx->values->put (slot, NULL_TREE); | |
1726 | } | |
1727 | else | |
1728 | ctx->values->put (res, NULL_TREE); | |
9c96033c | 1729 | |
4f7ebe46 | 1730 | /* Track the callee's evaluated SAVE_EXPRs so that we can forget |
1731 | their values after the call. */ | |
1732 | constexpr_ctx ctx_with_save_exprs = *ctx; | |
1733 | hash_set<tree> save_exprs; | |
1734 | ctx_with_save_exprs.save_exprs = &save_exprs; | |
43b7271d | 1735 | ctx_with_save_exprs.call = &new_call; |
4f7ebe46 | 1736 | |
88a59139 | 1737 | tree jump_target = NULL_TREE; |
4f7ebe46 | 1738 | cxx_eval_constant_expression (&ctx_with_save_exprs, body, |
88a59139 | 1739 | lval, non_constant_p, overflow_p, |
1740 | &jump_target); | |
9c96033c | 1741 | |
88a59139 | 1742 | if (DECL_CONSTRUCTOR_P (fun)) |
1743 | /* This can be null for a subobject constructor call, in | |
1744 | which case what we care about is the initialization | |
1745 | side-effects rather than the value. We could get at the | |
1746 | value by evaluating *this, but we don't bother; there's | |
1747 | no need to put such a call in the hash table. */ | |
1748 | result = lval ? ctx->object : ctx->ctor; | |
1749 | else if (VOID_TYPE_P (TREE_TYPE (res))) | |
1750 | result = void_node; | |
1751 | else | |
1752 | { | |
1753 | result = *ctx->values->get (slot ? slot : res); | |
1754 | if (result == NULL_TREE && !*non_constant_p) | |
9c96033c | 1755 | { |
88a59139 | 1756 | if (!ctx->quiet) |
5967b28b | 1757 | error ("%<constexpr%> call flows off the end " |
88a59139 | 1758 | "of the function"); |
1759 | *non_constant_p = true; | |
9c96033c | 1760 | } |
9c96033c | 1761 | } |
88a59139 | 1762 | |
4f7ebe46 | 1763 | /* Forget the saved values of the callee's SAVE_EXPRs. */ |
1764 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
1765 | iter != save_exprs.end(); ++iter) | |
1766 | ctx_with_save_exprs.values->remove (*iter); | |
1767 | ||
88a59139 | 1768 | /* Remove the parms/result from the values map. Is it worth |
1769 | bothering to do this when the map itself is only live for | |
1770 | one constexpr evaluation? If so, maybe also clear out | |
1771 | other vars from call, maybe in BIND_EXPR handling? */ | |
1772 | ctx->values->remove (res); | |
1773 | if (slot) | |
1774 | ctx->values->remove (slot); | |
1775 | for (tree parm = parms; parm; parm = TREE_CHAIN (parm)) | |
1776 | ctx->values->remove (parm); | |
4f7ebe46 | 1777 | |
1778 | /* Make the unshared function copy we used available for re-use. */ | |
1779 | save_fundef_copy (fun, copy); | |
cf72f34d | 1780 | } |
9c96033c | 1781 | |
09b42213 | 1782 | if (result == error_mark_node) |
1783 | *non_constant_p = true; | |
c3f376bf | 1784 | if (*non_constant_p || *overflow_p) |
c8f6aeb1 | 1785 | result = error_mark_node; |
88a59139 | 1786 | else if (!result) |
9c96033c | 1787 | result = void_node; |
c8f6aeb1 | 1788 | if (entry) |
1789 | entry->result = result; | |
09b42213 | 1790 | } |
1791 | ||
c6d97004 | 1792 | /* The result of a constexpr function must be completely initialized. */ |
1793 | if (TREE_CODE (result) == CONSTRUCTOR) | |
79cdb4f5 | 1794 | clear_no_implicit_zero (result); |
c6d97004 | 1795 | |
09b42213 | 1796 | pop_cx_call_context (); |
e283bb4f | 1797 | return unshare_constructor (result); |
09b42213 | 1798 | } |
1799 | ||
1800 | /* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */ | |
1801 | ||
1802 | bool | |
1803 | reduced_constant_expression_p (tree t) | |
1804 | { | |
a34934c2 | 1805 | if (t == NULL_TREE) |
1806 | return false; | |
1807 | ||
09b42213 | 1808 | switch (TREE_CODE (t)) |
1809 | { | |
1810 | case PTRMEM_CST: | |
1811 | /* Even if we can't lower this yet, it's constant. */ | |
1812 | return true; | |
1813 | ||
1814 | case CONSTRUCTOR: | |
1815 | /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */ | |
56da7fe6 | 1816 | tree idx, val, field; unsigned HOST_WIDE_INT i; |
165d0d5b | 1817 | if (CONSTRUCTOR_NO_CLEARING (t)) |
c4210852 | 1818 | { |
1819 | if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE) | |
1820 | /* An initialized vector would have a VECTOR_CST. */ | |
1821 | return false; | |
1822 | else | |
1823 | field = next_initializable_field (TYPE_FIELDS (TREE_TYPE (t))); | |
1824 | } | |
56da7fe6 | 1825 | else |
1826 | field = NULL_TREE; | |
1827 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t), i, idx, val) | |
ce4ffd9e | 1828 | { |
a34934c2 | 1829 | /* If VAL is null, we're in the middle of initializing this |
1830 | element. */ | |
56da7fe6 | 1831 | if (!reduced_constant_expression_p (val)) |
ce4ffd9e | 1832 | return false; |
56da7fe6 | 1833 | if (field) |
1834 | { | |
1835 | if (idx != field) | |
1836 | return false; | |
1837 | field = next_initializable_field (DECL_CHAIN (field)); | |
1838 | } | |
ce4ffd9e | 1839 | } |
56da7fe6 | 1840 | if (field) |
1841 | return false; | |
165d0d5b | 1842 | else if (CONSTRUCTOR_NO_CLEARING (t)) |
56da7fe6 | 1843 | /* All the fields are initialized. */ |
165d0d5b | 1844 | CONSTRUCTOR_NO_CLEARING (t) = false; |
09b42213 | 1845 | return true; |
1846 | ||
1847 | default: | |
1848 | /* FIXME are we calling this too much? */ | |
1849 | return initializer_constant_valid_p (t, TREE_TYPE (t)) != NULL_TREE; | |
1850 | } | |
1851 | } | |
1852 | ||
1853 | /* Some expressions may have constant operands but are not constant | |
941fafa5 | 1854 | themselves, such as 1/0. Call this function to check for that |
1855 | condition. | |
09b42213 | 1856 | |
1857 | We only call this in places that require an arithmetic constant, not in | |
1858 | places where we might have a non-constant expression that can be a | |
1859 | component of a constant expression, such as the address of a constexpr | |
1860 | variable that might be dereferenced later. */ | |
1861 | ||
1862 | static bool | |
1863 | verify_constant (tree t, bool allow_non_constant, bool *non_constant_p, | |
1864 | bool *overflow_p) | |
1865 | { | |
1866 | if (!*non_constant_p && !reduced_constant_expression_p (t)) | |
1867 | { | |
1868 | if (!allow_non_constant) | |
1869 | error ("%q+E is not a constant expression", t); | |
1870 | *non_constant_p = true; | |
1871 | } | |
1872 | if (TREE_OVERFLOW_P (t)) | |
1873 | { | |
1874 | if (!allow_non_constant) | |
1875 | { | |
1876 | permerror (input_location, "overflow in constant expression"); | |
1877 | /* If we're being permissive (and are in an enforcing | |
1878 | context), ignore the overflow. */ | |
1879 | if (flag_permissive) | |
1880 | return *non_constant_p; | |
1881 | } | |
1882 | *overflow_p = true; | |
1883 | } | |
1884 | return *non_constant_p; | |
1885 | } | |
1886 | ||
2b035ffe | 1887 | /* Check whether the shift operation with code CODE and type TYPE on LHS |
1888 | and RHS is undefined. If it is, give an error with an explanation, | |
1889 | and return true; return false otherwise. */ | |
1890 | ||
1891 | static bool | |
1892 | cxx_eval_check_shift_p (location_t loc, const constexpr_ctx *ctx, | |
1893 | enum tree_code code, tree type, tree lhs, tree rhs) | |
1894 | { | |
1895 | if ((code != LSHIFT_EXPR && code != RSHIFT_EXPR) | |
1896 | || TREE_CODE (lhs) != INTEGER_CST | |
1897 | || TREE_CODE (rhs) != INTEGER_CST) | |
1898 | return false; | |
1899 | ||
1900 | tree lhstype = TREE_TYPE (lhs); | |
1901 | unsigned HOST_WIDE_INT uprec = TYPE_PRECISION (TREE_TYPE (lhs)); | |
1902 | ||
1903 | /* [expr.shift] The behavior is undefined if the right operand | |
1904 | is negative, or greater than or equal to the length in bits | |
1905 | of the promoted left operand. */ | |
1906 | if (tree_int_cst_sgn (rhs) == -1) | |
1907 | { | |
1908 | if (!ctx->quiet) | |
91d87e22 | 1909 | permerror (loc, "right operand of shift expression %q+E is negative", |
1910 | build2_loc (loc, code, type, lhs, rhs)); | |
1911 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1912 | } |
1913 | if (compare_tree_int (rhs, uprec) >= 0) | |
1914 | { | |
1915 | if (!ctx->quiet) | |
91d87e22 | 1916 | permerror (loc, "right operand of shift expression %q+E is >= than " |
1917 | "the precision of the left operand", | |
1918 | build2_loc (loc, code, type, lhs, rhs)); | |
1919 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1920 | } |
1921 | ||
1922 | /* The value of E1 << E2 is E1 left-shifted E2 bit positions; [...] | |
1923 | if E1 has a signed type and non-negative value, and E1x2^E2 is | |
1924 | representable in the corresponding unsigned type of the result type, | |
1925 | then that value, converted to the result type, is the resulting value; | |
1170ee75 | 1926 | otherwise, the behavior is undefined. |
1927 | For C++2a: | |
1928 | The value of E1 << E2 is the unique value congruent to E1 x 2^E2 modulo | |
1929 | 2^N, where N is the range exponent of the type of the result. */ | |
1930 | if (code == LSHIFT_EXPR | |
1931 | && !TYPE_UNSIGNED (lhstype) | |
1932 | && cxx_dialect >= cxx11 | |
1933 | && cxx_dialect < cxx2a) | |
2b035ffe | 1934 | { |
1935 | if (tree_int_cst_sgn (lhs) == -1) | |
1936 | { | |
1937 | if (!ctx->quiet) | |
91d87e22 | 1938 | permerror (loc, |
1939 | "left operand of shift expression %q+E is negative", | |
1940 | build2_loc (loc, code, type, lhs, rhs)); | |
1941 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1942 | } |
1943 | /* For signed x << y the following: | |
1944 | (unsigned) x >> ((prec (lhs) - 1) - y) | |
1945 | if > 1, is undefined. The right-hand side of this formula | |
1946 | is the highest bit of the LHS that can be set (starting from 0), | |
1947 | so that the shift doesn't overflow. We then right-shift the LHS | |
1948 | to see whether any other bit is set making the original shift | |
1949 | undefined -- the result is not representable in the corresponding | |
1950 | unsigned type. */ | |
1951 | tree t = build_int_cst (unsigned_type_node, uprec - 1); | |
1952 | t = fold_build2 (MINUS_EXPR, unsigned_type_node, t, rhs); | |
1953 | tree ulhs = fold_convert (unsigned_type_for (lhstype), lhs); | |
1954 | t = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ulhs), ulhs, t); | |
1955 | if (tree_int_cst_lt (integer_one_node, t)) | |
1956 | { | |
1957 | if (!ctx->quiet) | |
91d87e22 | 1958 | permerror (loc, "shift expression %q+E overflows", |
1959 | build2_loc (loc, code, type, lhs, rhs)); | |
1960 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1961 | } |
1962 | } | |
1963 | return false; | |
1964 | } | |
1965 | ||
09b42213 | 1966 | /* Subroutine of cxx_eval_constant_expression. |
1967 | Attempt to reduce the unary expression tree T to a compile time value. | |
1968 | If successful, return the value. Otherwise issue a diagnostic | |
1969 | and return error_mark_node. */ | |
1970 | ||
1971 | static tree | |
cf72f34d | 1972 | cxx_eval_unary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 1973 | bool /*lval*/, |
09b42213 | 1974 | bool *non_constant_p, bool *overflow_p) |
1975 | { | |
1976 | tree r; | |
1977 | tree orig_arg = TREE_OPERAND (t, 0); | |
c8f6aeb1 | 1978 | tree arg = cxx_eval_constant_expression (ctx, orig_arg, /*lval*/false, |
1979 | non_constant_p, overflow_p); | |
09b42213 | 1980 | VERIFY_CONSTANT (arg); |
93add516 | 1981 | location_t loc = EXPR_LOCATION (t); |
1982 | enum tree_code code = TREE_CODE (t); | |
1983 | tree type = TREE_TYPE (t); | |
1984 | r = fold_unary_loc (loc, code, type, arg); | |
1985 | if (r == NULL_TREE) | |
1986 | { | |
1987 | if (arg == orig_arg) | |
1988 | r = t; | |
1989 | else | |
1990 | r = build1_loc (loc, code, type, arg); | |
1991 | } | |
09b42213 | 1992 | VERIFY_CONSTANT (r); |
1993 | return r; | |
1994 | } | |
1995 | ||
46fad8d5 | 1996 | /* Helper function for cxx_eval_binary_expression. Try to optimize |
1997 | original POINTER_PLUS_EXPR T, LHS p+ RHS, return NULL_TREE if the | |
1998 | generic folding should be used. */ | |
1999 | ||
2000 | static tree | |
2001 | cxx_fold_pointer_plus_expression (const constexpr_ctx *ctx, tree t, | |
2002 | tree lhs, tree rhs, bool *non_constant_p, | |
2003 | bool *overflow_p) | |
2004 | { | |
2005 | STRIP_NOPS (lhs); | |
2006 | if (TREE_CODE (lhs) != ADDR_EXPR) | |
2007 | return NULL_TREE; | |
2008 | ||
2009 | lhs = TREE_OPERAND (lhs, 0); | |
2010 | ||
2011 | /* &A[i] p+ j => &A[i + j] */ | |
2012 | if (TREE_CODE (lhs) == ARRAY_REF | |
2013 | && TREE_CODE (TREE_OPERAND (lhs, 1)) == INTEGER_CST | |
2014 | && TREE_CODE (rhs) == INTEGER_CST | |
2015 | && TYPE_SIZE_UNIT (TREE_TYPE (lhs)) | |
2016 | && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (lhs))) == INTEGER_CST) | |
2017 | { | |
2018 | tree orig_type = TREE_TYPE (t); | |
2019 | location_t loc = EXPR_LOCATION (t); | |
2020 | tree type = TREE_TYPE (lhs); | |
2021 | ||
2022 | t = fold_convert_loc (loc, ssizetype, TREE_OPERAND (lhs, 1)); | |
2023 | tree nelts = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (lhs, 0))); | |
2024 | nelts = cxx_eval_constant_expression (ctx, nelts, false, non_constant_p, | |
2025 | overflow_p); | |
2026 | if (*non_constant_p) | |
2027 | return NULL_TREE; | |
2028 | /* Don't fold an out-of-bound access. */ | |
2029 | if (!tree_int_cst_le (t, nelts)) | |
2030 | return NULL_TREE; | |
2031 | rhs = cp_fold_convert (ssizetype, rhs); | |
2032 | /* Don't fold if rhs can't be divided exactly by TYPE_SIZE_UNIT. | |
2033 | constexpr int A[1]; ... (char *)&A[0] + 1 */ | |
2034 | if (!integer_zerop (fold_build2_loc (loc, TRUNC_MOD_EXPR, sizetype, | |
2035 | rhs, TYPE_SIZE_UNIT (type)))) | |
2036 | return NULL_TREE; | |
2037 | /* Make sure to treat the second operand of POINTER_PLUS_EXPR | |
2038 | as signed. */ | |
2039 | rhs = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, rhs, | |
2040 | TYPE_SIZE_UNIT (type)); | |
2041 | t = size_binop_loc (loc, PLUS_EXPR, rhs, t); | |
2042 | t = build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (lhs, 0), | |
2043 | t, NULL_TREE, NULL_TREE); | |
2044 | t = cp_build_addr_expr (t, tf_warning_or_error); | |
2045 | t = cp_fold_convert (orig_type, t); | |
2046 | return cxx_eval_constant_expression (ctx, t, /*lval*/false, | |
2047 | non_constant_p, overflow_p); | |
2048 | } | |
2049 | ||
2050 | return NULL_TREE; | |
2051 | } | |
2052 | ||
09b42213 | 2053 | /* Subroutine of cxx_eval_constant_expression. |
2054 | Like cxx_eval_unary_expression, except for binary expressions. */ | |
2055 | ||
2056 | static tree | |
cf72f34d | 2057 | cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 2058 | bool /*lval*/, |
09b42213 | 2059 | bool *non_constant_p, bool *overflow_p) |
2060 | { | |
f7ef5392 | 2061 | tree r = NULL_TREE; |
09b42213 | 2062 | tree orig_lhs = TREE_OPERAND (t, 0); |
2063 | tree orig_rhs = TREE_OPERAND (t, 1); | |
2064 | tree lhs, rhs; | |
c8f6aeb1 | 2065 | lhs = cxx_eval_constant_expression (ctx, orig_lhs, /*lval*/false, |
b2a43197 | 2066 | non_constant_p, overflow_p); |
6d6737d9 | 2067 | /* Don't VERIFY_CONSTANT here, it's unnecessary and will break pointer |
2068 | subtraction. */ | |
2069 | if (*non_constant_p) | |
2070 | return t; | |
c8f6aeb1 | 2071 | rhs = cxx_eval_constant_expression (ctx, orig_rhs, /*lval*/false, |
b2a43197 | 2072 | non_constant_p, overflow_p); |
6d6737d9 | 2073 | if (*non_constant_p) |
2074 | return t; | |
93add516 | 2075 | |
2076 | location_t loc = EXPR_LOCATION (t); | |
2077 | enum tree_code code = TREE_CODE (t); | |
2078 | tree type = TREE_TYPE (t); | |
f7ef5392 | 2079 | |
2080 | if (code == EQ_EXPR || code == NE_EXPR) | |
2081 | { | |
2082 | bool is_code_eq = (code == EQ_EXPR); | |
2083 | ||
2084 | if (TREE_CODE (lhs) == PTRMEM_CST | |
2085 | && TREE_CODE (rhs) == PTRMEM_CST) | |
e9f29fe5 | 2086 | { |
2087 | tree lmem = PTRMEM_CST_MEMBER (lhs); | |
2088 | tree rmem = PTRMEM_CST_MEMBER (rhs); | |
2089 | bool eq; | |
2090 | if (TREE_CODE (lmem) == TREE_CODE (rmem) | |
2091 | && TREE_CODE (lmem) == FIELD_DECL | |
2092 | && TREE_CODE (DECL_CONTEXT (lmem)) == UNION_TYPE | |
2093 | && same_type_p (DECL_CONTEXT (lmem), | |
2094 | DECL_CONTEXT (rmem))) | |
2095 | /* If both refer to (possibly different) members of the same union | |
2096 | (12.3), they compare equal. */ | |
2097 | eq = true; | |
2098 | else | |
2099 | eq = cp_tree_equal (lhs, rhs); | |
2100 | r = constant_boolean_node (eq == is_code_eq, type); | |
2101 | } | |
f7ef5392 | 2102 | else if ((TREE_CODE (lhs) == PTRMEM_CST |
2103 | || TREE_CODE (rhs) == PTRMEM_CST) | |
2104 | && (null_member_pointer_value_p (lhs) | |
2105 | || null_member_pointer_value_p (rhs))) | |
2106 | r = constant_boolean_node (!is_code_eq, type); | |
f31f4e9c | 2107 | else if (TREE_CODE (lhs) == PTRMEM_CST) |
2108 | lhs = cplus_expand_constant (lhs); | |
2109 | else if (TREE_CODE (rhs) == PTRMEM_CST) | |
2110 | rhs = cplus_expand_constant (rhs); | |
f7ef5392 | 2111 | } |
cb768824 | 2112 | if (code == POINTER_PLUS_EXPR && !*non_constant_p |
2113 | && integer_zerop (lhs) && !integer_zerop (rhs)) | |
2114 | { | |
2115 | if (!ctx->quiet) | |
2116 | error ("arithmetic involving a null pointer in %qE", lhs); | |
2b1749c4 | 2117 | *non_constant_p = true; |
cb768824 | 2118 | return t; |
2119 | } | |
46fad8d5 | 2120 | else if (code == POINTER_PLUS_EXPR) |
2121 | r = cxx_fold_pointer_plus_expression (ctx, t, lhs, rhs, non_constant_p, | |
2122 | overflow_p); | |
f7ef5392 | 2123 | |
2124 | if (r == NULL_TREE) | |
2125 | r = fold_binary_loc (loc, code, type, lhs, rhs); | |
2126 | ||
93add516 | 2127 | if (r == NULL_TREE) |
2128 | { | |
2129 | if (lhs == orig_lhs && rhs == orig_rhs) | |
2130 | r = t; | |
2131 | else | |
2132 | r = build2_loc (loc, code, type, lhs, rhs); | |
2133 | } | |
2b035ffe | 2134 | else if (cxx_eval_check_shift_p (loc, ctx, code, type, lhs, rhs)) |
2135 | *non_constant_p = true; | |
6d6737d9 | 2136 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
2137 | a local array in a constexpr function. */ | |
d03fa520 | 2138 | bool ptr = INDIRECT_TYPE_P (TREE_TYPE (lhs)); |
35f2c28f | 2139 | if (!ptr) |
aae7465c | 2140 | VERIFY_CONSTANT (r); |
09b42213 | 2141 | return r; |
2142 | } | |
2143 | ||
2144 | /* Subroutine of cxx_eval_constant_expression. | |
2145 | Attempt to evaluate condition expressions. Dead branches are not | |
2146 | looked into. */ | |
2147 | ||
2148 | static tree | |
cf72f34d | 2149 | cxx_eval_conditional_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2150 | bool lval, |
00f21715 | 2151 | bool *non_constant_p, bool *overflow_p, |
2152 | tree *jump_target) | |
09b42213 | 2153 | { |
cf72f34d | 2154 | tree val = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
c8f6aeb1 | 2155 | /*lval*/false, |
b2a43197 | 2156 | non_constant_p, overflow_p); |
09b42213 | 2157 | VERIFY_CONSTANT (val); |
2158 | /* Don't VERIFY_CONSTANT the other operands. */ | |
2159 | if (integer_zerop (val)) | |
cf72f34d | 2160 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), |
1227ba74 | 2161 | lval, |
00f21715 | 2162 | non_constant_p, overflow_p, |
2163 | jump_target); | |
cf72f34d | 2164 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2165 | lval, |
00f21715 | 2166 | non_constant_p, overflow_p, |
2167 | jump_target); | |
09b42213 | 2168 | } |
2169 | ||
31595caf | 2170 | /* Subroutine of cxx_eval_constant_expression. |
2171 | Attempt to evaluate vector condition expressions. Unlike | |
2172 | cxx_eval_conditional_expression, VEC_COND_EXPR acts like a normal | |
2173 | ternary arithmetics operation, where all 3 arguments have to be | |
2174 | evaluated as constants and then folding computes the result from | |
2175 | them. */ | |
2176 | ||
2177 | static tree | |
2178 | cxx_eval_vector_conditional_expression (const constexpr_ctx *ctx, tree t, | |
2179 | bool *non_constant_p, bool *overflow_p) | |
2180 | { | |
2181 | tree arg1 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
2182 | /*lval*/false, | |
2183 | non_constant_p, overflow_p); | |
2184 | VERIFY_CONSTANT (arg1); | |
2185 | tree arg2 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
2186 | /*lval*/false, | |
2187 | non_constant_p, overflow_p); | |
2188 | VERIFY_CONSTANT (arg2); | |
2189 | tree arg3 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
2190 | /*lval*/false, | |
2191 | non_constant_p, overflow_p); | |
2192 | VERIFY_CONSTANT (arg3); | |
2193 | location_t loc = EXPR_LOCATION (t); | |
2194 | tree type = TREE_TYPE (t); | |
2195 | tree r = fold_ternary_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2196 | if (r == NULL_TREE) | |
2197 | { | |
2198 | if (arg1 == TREE_OPERAND (t, 0) | |
2199 | && arg2 == TREE_OPERAND (t, 1) | |
2200 | && arg3 == TREE_OPERAND (t, 2)) | |
2201 | r = t; | |
2202 | else | |
2203 | r = build3_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2204 | } | |
2205 | VERIFY_CONSTANT (r); | |
2206 | return r; | |
2207 | } | |
2208 | ||
7963b19d | 2209 | /* Returns less than, equal to, or greater than zero if KEY is found to be |
2210 | less than, to match, or to be greater than the constructor_elt's INDEX. */ | |
2211 | ||
2212 | static int | |
2213 | array_index_cmp (tree key, tree index) | |
2214 | { | |
2215 | gcc_assert (TREE_CODE (key) == INTEGER_CST); | |
2216 | ||
2217 | switch (TREE_CODE (index)) | |
2218 | { | |
2219 | case INTEGER_CST: | |
2220 | return tree_int_cst_compare (key, index); | |
2221 | case RANGE_EXPR: | |
2222 | { | |
2223 | tree lo = TREE_OPERAND (index, 0); | |
2224 | tree hi = TREE_OPERAND (index, 1); | |
2225 | if (tree_int_cst_lt (key, lo)) | |
2226 | return -1; | |
2227 | else if (tree_int_cst_lt (hi, key)) | |
2228 | return 1; | |
2229 | else | |
2230 | return 0; | |
2231 | } | |
2232 | default: | |
2233 | gcc_unreachable (); | |
2234 | } | |
2235 | } | |
2236 | ||
2237 | /* Returns the index of the constructor_elt of ARY which matches DINDEX, or -1 | |
2238 | if none. If INSERT is true, insert a matching element rather than fail. */ | |
2239 | ||
2240 | static HOST_WIDE_INT | |
2241 | find_array_ctor_elt (tree ary, tree dindex, bool insert = false) | |
2242 | { | |
2243 | if (tree_int_cst_sgn (dindex) < 0) | |
2244 | return -1; | |
2245 | ||
2246 | unsigned HOST_WIDE_INT i = tree_to_uhwi (dindex); | |
2247 | vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (ary); | |
2248 | unsigned HOST_WIDE_INT len = vec_safe_length (elts); | |
2249 | ||
2250 | unsigned HOST_WIDE_INT end = len; | |
2251 | unsigned HOST_WIDE_INT begin = 0; | |
2252 | ||
2253 | /* If the last element of the CONSTRUCTOR has its own index, we can assume | |
2254 | that the same is true of the other elements and index directly. */ | |
2255 | if (end > 0) | |
2256 | { | |
e99466d6 | 2257 | tree cindex = (*elts)[end - 1].index; |
7963b19d | 2258 | if (TREE_CODE (cindex) == INTEGER_CST |
e99466d6 | 2259 | && compare_tree_int (cindex, end - 1) == 0) |
7963b19d | 2260 | { |
2261 | if (i < end) | |
2262 | return i; | |
2263 | else | |
2264 | begin = end; | |
2265 | } | |
2266 | } | |
2267 | ||
2268 | /* Otherwise, find a matching index by means of a binary search. */ | |
2269 | while (begin != end) | |
2270 | { | |
2271 | unsigned HOST_WIDE_INT middle = (begin + end) / 2; | |
f0b916c7 | 2272 | constructor_elt &elt = (*elts)[middle]; |
2273 | tree idx = elt.index; | |
7963b19d | 2274 | |
f0b916c7 | 2275 | int cmp = array_index_cmp (dindex, idx); |
7963b19d | 2276 | if (cmp < 0) |
2277 | end = middle; | |
2278 | else if (cmp > 0) | |
2279 | begin = middle + 1; | |
2280 | else | |
f0b916c7 | 2281 | { |
2282 | if (insert && TREE_CODE (idx) == RANGE_EXPR) | |
2283 | { | |
2284 | /* We need to split the range. */ | |
2285 | constructor_elt e; | |
2286 | tree lo = TREE_OPERAND (idx, 0); | |
2287 | tree hi = TREE_OPERAND (idx, 1); | |
e99466d6 | 2288 | tree value = elt.value; |
2289 | dindex = fold_convert (sizetype, dindex); | |
f0b916c7 | 2290 | if (tree_int_cst_lt (lo, dindex)) |
2291 | { | |
2292 | /* There are still some lower elts; shorten the range. */ | |
2293 | tree new_hi = int_const_binop (MINUS_EXPR, dindex, | |
2294 | size_one_node); | |
2295 | if (tree_int_cst_equal (lo, new_hi)) | |
2296 | /* Only one element left, no longer a range. */ | |
2297 | elt.index = lo; | |
2298 | else | |
2299 | TREE_OPERAND (idx, 1) = new_hi; | |
2300 | /* Append the element we want to insert. */ | |
2301 | ++middle; | |
2302 | e.index = dindex; | |
e99466d6 | 2303 | e.value = unshare_constructor (value); |
f0b916c7 | 2304 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle, e); |
2305 | } | |
2306 | else | |
2307 | /* No lower elts, the range elt is now ours. */ | |
2308 | elt.index = dindex; | |
2309 | ||
2310 | if (tree_int_cst_lt (dindex, hi)) | |
2311 | { | |
2312 | /* There are still some higher elts; append a range. */ | |
2313 | tree new_lo = int_const_binop (PLUS_EXPR, dindex, | |
2314 | size_one_node); | |
2315 | if (tree_int_cst_equal (new_lo, hi)) | |
2316 | e.index = hi; | |
2317 | else | |
2318 | e.index = build2 (RANGE_EXPR, sizetype, new_lo, hi); | |
e99466d6 | 2319 | e.value = unshare_constructor (value); |
2320 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle + 1, e); | |
f0b916c7 | 2321 | } |
2322 | } | |
2323 | return middle; | |
2324 | } | |
7963b19d | 2325 | } |
2326 | ||
2327 | if (insert) | |
2328 | { | |
2329 | constructor_elt e = { dindex, NULL_TREE }; | |
2330 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), end, e); | |
2331 | return end; | |
2332 | } | |
2333 | ||
2334 | return -1; | |
2335 | } | |
2336 | ||
40df9099 | 2337 | /* Under the control of CTX, issue a detailed diagnostic for |
2338 | an out-of-bounds subscript INDEX into the expression ARRAY. */ | |
2339 | ||
2340 | static void | |
2341 | diag_array_subscript (const constexpr_ctx *ctx, tree array, tree index) | |
2342 | { | |
2343 | if (!ctx->quiet) | |
2344 | { | |
2345 | tree arraytype = TREE_TYPE (array); | |
2346 | ||
2347 | /* Convert the unsigned array subscript to a signed integer to avoid | |
2348 | printing huge numbers for small negative values. */ | |
2349 | tree sidx = fold_convert (ssizetype, index); | |
2350 | if (DECL_P (array)) | |
2351 | { | |
d7d265db | 2352 | if (TYPE_DOMAIN (arraytype)) |
2353 | error ("array subscript value %qE is outside the bounds " | |
2354 | "of array %qD of type %qT", sidx, array, arraytype); | |
2355 | else | |
2356 | error ("non-zero array subscript %qE is used with array %qD of " | |
2357 | "type %qT with unknown bounds", sidx, array, arraytype); | |
40df9099 | 2358 | inform (DECL_SOURCE_LOCATION (array), "declared here"); |
2359 | } | |
d7d265db | 2360 | else if (TYPE_DOMAIN (arraytype)) |
40df9099 | 2361 | error ("array subscript value %qE is outside the bounds " |
2362 | "of array type %qT", sidx, arraytype); | |
d7d265db | 2363 | else |
2364 | error ("non-zero array subscript %qE is used with array of type %qT " | |
2365 | "with unknown bounds", sidx, arraytype); | |
40df9099 | 2366 | } |
2367 | } | |
7963b19d | 2368 | |
51f0c7e2 | 2369 | /* Return the number of elements for TYPE (which is an ARRAY_TYPE or |
2370 | a VECTOR_TYPE). */ | |
2371 | ||
2372 | static tree | |
2373 | get_array_or_vector_nelts (const constexpr_ctx *ctx, tree type, | |
2374 | bool *non_constant_p, bool *overflow_p) | |
2375 | { | |
2376 | tree nelts; | |
2377 | if (TREE_CODE (type) == ARRAY_TYPE) | |
2378 | { | |
2379 | if (TYPE_DOMAIN (type)) | |
2380 | nelts = array_type_nelts_top (type); | |
2381 | else | |
2382 | nelts = size_zero_node; | |
2383 | } | |
2384 | else if (VECTOR_TYPE_P (type)) | |
2385 | nelts = size_int (TYPE_VECTOR_SUBPARTS (type)); | |
2386 | else | |
2387 | gcc_unreachable (); | |
2388 | ||
2389 | /* For VLAs, the number of elements won't be an integer constant. */ | |
2390 | nelts = cxx_eval_constant_expression (ctx, nelts, false, | |
2391 | non_constant_p, overflow_p); | |
2392 | return nelts; | |
2393 | } | |
2394 | ||
92fe8840 | 2395 | /* Extract element INDEX consisting of CHARS_PER_ELT chars from |
2396 | STRING_CST STRING. */ | |
2397 | ||
2398 | static tree | |
2399 | extract_string_elt (tree string, unsigned chars_per_elt, unsigned index) | |
2400 | { | |
2401 | tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (string))); | |
2402 | tree r; | |
2403 | ||
2404 | if (chars_per_elt == 1) | |
2405 | r = build_int_cst (type, TREE_STRING_POINTER (string)[index]); | |
2406 | else | |
2407 | { | |
2408 | const unsigned char *ptr | |
2409 | = ((const unsigned char *)TREE_STRING_POINTER (string) | |
2410 | + index * chars_per_elt); | |
2411 | r = native_interpret_expr (type, ptr, chars_per_elt); | |
2412 | } | |
2413 | return r; | |
2414 | } | |
2415 | ||
09b42213 | 2416 | /* Subroutine of cxx_eval_constant_expression. |
2417 | Attempt to reduce a reference to an array slot. */ | |
2418 | ||
2419 | static tree | |
cf72f34d | 2420 | cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2421 | bool lval, |
09b42213 | 2422 | bool *non_constant_p, bool *overflow_p) |
2423 | { | |
2424 | tree oldary = TREE_OPERAND (t, 0); | |
cf72f34d | 2425 | tree ary = cxx_eval_constant_expression (ctx, oldary, |
1227ba74 | 2426 | lval, |
b2a43197 | 2427 | non_constant_p, overflow_p); |
09b42213 | 2428 | tree index, oldidx; |
cf3cefc9 | 2429 | HOST_WIDE_INT i = 0; |
2430 | tree elem_type = NULL_TREE; | |
2431 | unsigned len = 0, elem_nchars = 1; | |
09b42213 | 2432 | if (*non_constant_p) |
2433 | return t; | |
2434 | oldidx = TREE_OPERAND (t, 1); | |
cf72f34d | 2435 | index = cxx_eval_constant_expression (ctx, oldidx, |
f83e6885 | 2436 | false, |
b2a43197 | 2437 | non_constant_p, overflow_p); |
09b42213 | 2438 | VERIFY_CONSTANT (index); |
cf3cefc9 | 2439 | if (!lval) |
09b42213 | 2440 | { |
cf3cefc9 | 2441 | elem_type = TREE_TYPE (TREE_TYPE (ary)); |
2442 | if (TREE_CODE (ary) == VIEW_CONVERT_EXPR | |
2443 | && VECTOR_TYPE_P (TREE_TYPE (TREE_OPERAND (ary, 0))) | |
2444 | && TREE_TYPE (t) == TREE_TYPE (TREE_TYPE (TREE_OPERAND (ary, 0)))) | |
2445 | ary = TREE_OPERAND (ary, 0); | |
2446 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2447 | len = CONSTRUCTOR_NELTS (ary); | |
2448 | else if (TREE_CODE (ary) == STRING_CST) | |
2449 | { | |
2450 | elem_nchars = (TYPE_PRECISION (elem_type) | |
2451 | / TYPE_PRECISION (char_type_node)); | |
2452 | len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars; | |
2453 | } | |
2454 | else if (TREE_CODE (ary) == VECTOR_CST) | |
f08ee65f | 2455 | /* We don't create variable-length VECTOR_CSTs. */ |
2456 | len = VECTOR_CST_NELTS (ary).to_constant (); | |
cf3cefc9 | 2457 | else |
2458 | { | |
2459 | /* We can't do anything with other tree codes, so use | |
2460 | VERIFY_CONSTANT to complain and fail. */ | |
2461 | VERIFY_CONSTANT (ary); | |
2462 | gcc_unreachable (); | |
2463 | } | |
aed8dc7f | 2464 | |
cf3cefc9 | 2465 | if (!tree_fits_shwi_p (index) |
2466 | || (i = tree_to_shwi (index)) < 0) | |
2467 | { | |
2468 | diag_array_subscript (ctx, ary, index); | |
2469 | *non_constant_p = true; | |
2470 | return t; | |
2471 | } | |
7963b19d | 2472 | } |
2473 | ||
51f0c7e2 | 2474 | tree nelts = get_array_or_vector_nelts (ctx, TREE_TYPE (ary), non_constant_p, |
2475 | overflow_p); | |
ce6a6978 | 2476 | VERIFY_CONSTANT (nelts); |
0acc6340 | 2477 | if ((lval |
2478 | ? !tree_int_cst_le (index, nelts) | |
2479 | : !tree_int_cst_lt (index, nelts)) | |
2480 | || tree_int_cst_sgn (index) < 0) | |
ce6a6978 | 2481 | { |
40df9099 | 2482 | diag_array_subscript (ctx, ary, index); |
ce6a6978 | 2483 | *non_constant_p = true; |
2484 | return t; | |
2485 | } | |
2486 | ||
cf3cefc9 | 2487 | if (lval && ary == oldary && index == oldidx) |
2488 | return t; | |
2489 | else if (lval) | |
2490 | return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL); | |
2491 | ||
7963b19d | 2492 | bool found; |
2493 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2494 | { | |
2495 | HOST_WIDE_INT ix = find_array_ctor_elt (ary, index); | |
2496 | found = (ix >= 0); | |
2497 | if (found) | |
2498 | i = ix; | |
aed8dc7f | 2499 | } |
7963b19d | 2500 | else |
2501 | found = (i < len); | |
aed8dc7f | 2502 | |
14869f28 | 2503 | if (found) |
2504 | { | |
2505 | tree r; | |
2506 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2507 | r = (*CONSTRUCTOR_ELTS (ary))[i].value; | |
2508 | else if (TREE_CODE (ary) == VECTOR_CST) | |
2509 | r = VECTOR_CST_ELT (ary, i); | |
14869f28 | 2510 | else |
92fe8840 | 2511 | r = extract_string_elt (ary, elem_nchars, i); |
2512 | ||
14869f28 | 2513 | if (r) |
2514 | /* Don't VERIFY_CONSTANT here. */ | |
2515 | return r; | |
09b42213 | 2516 | |
14869f28 | 2517 | /* Otherwise the element doesn't have a value yet. */ |
09b42213 | 2518 | } |
aed8dc7f | 2519 | |
14869f28 | 2520 | /* Not found. */ |
2521 | ||
2522 | if (TREE_CODE (ary) == CONSTRUCTOR | |
165d0d5b | 2523 | && CONSTRUCTOR_NO_CLEARING (ary)) |
09b42213 | 2524 | { |
14869f28 | 2525 | /* 'ary' is part of the aggregate initializer we're currently |
2526 | building; if there's no initializer for this element yet, | |
2527 | that's an error. */ | |
2528 | if (!ctx->quiet) | |
2529 | error ("accessing uninitialized array element"); | |
2530 | *non_constant_p = true; | |
2531 | return t; | |
09b42213 | 2532 | } |
14869f28 | 2533 | |
2534 | /* If it's within the array bounds but doesn't have an explicit | |
2535 | initializer, it's value-initialized. */ | |
2536 | tree val = build_value_init (elem_type, tf_warning_or_error); | |
2537 | return cxx_eval_constant_expression (ctx, val, lval, non_constant_p, | |
2538 | overflow_p); | |
09b42213 | 2539 | } |
2540 | ||
2541 | /* Subroutine of cxx_eval_constant_expression. | |
2542 | Attempt to reduce a field access of a value of class type. */ | |
2543 | ||
2544 | static tree | |
cf72f34d | 2545 | cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2546 | bool lval, |
09b42213 | 2547 | bool *non_constant_p, bool *overflow_p) |
2548 | { | |
2549 | unsigned HOST_WIDE_INT i; | |
2550 | tree field; | |
2551 | tree value; | |
2552 | tree part = TREE_OPERAND (t, 1); | |
2553 | tree orig_whole = TREE_OPERAND (t, 0); | |
cf72f34d | 2554 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2555 | lval, |
b2a43197 | 2556 | non_constant_p, overflow_p); |
7ab20d7c | 2557 | if (INDIRECT_REF_P (whole) |
2b1749c4 | 2558 | && integer_zerop (TREE_OPERAND (whole, 0))) |
2559 | { | |
2560 | if (!ctx->quiet) | |
2561 | error ("dereferencing a null pointer in %qE", orig_whole); | |
2562 | *non_constant_p = true; | |
2563 | return t; | |
2564 | } | |
cb768824 | 2565 | |
f16ed232 | 2566 | if (TREE_CODE (whole) == PTRMEM_CST) |
2567 | whole = cplus_expand_constant (whole); | |
09b42213 | 2568 | if (whole == orig_whole) |
2569 | return t; | |
1227ba74 | 2570 | if (lval) |
09b42213 | 2571 | return fold_build3 (COMPONENT_REF, TREE_TYPE (t), |
2572 | whole, part, NULL_TREE); | |
2573 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2574 | CONSTRUCTOR. */ | |
2575 | if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR) | |
2576 | { | |
f83e6885 | 2577 | if (!ctx->quiet) |
09b42213 | 2578 | error ("%qE is not a constant expression", orig_whole); |
2579 | *non_constant_p = true; | |
2580 | } | |
2581 | if (DECL_MUTABLE_P (part)) | |
2582 | { | |
f83e6885 | 2583 | if (!ctx->quiet) |
09b42213 | 2584 | error ("mutable %qD is not usable in a constant expression", part); |
2585 | *non_constant_p = true; | |
2586 | } | |
2587 | if (*non_constant_p) | |
2588 | return t; | |
a4360e57 | 2589 | bool pmf = TYPE_PTRMEMFUNC_P (TREE_TYPE (whole)); |
09b42213 | 2590 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) |
2591 | { | |
a4360e57 | 2592 | /* Use name match for PMF fields, as a variant will have a |
2593 | different FIELD_DECL with a different type. */ | |
2594 | if (pmf ? DECL_NAME (field) == DECL_NAME (part) | |
2595 | : field == part) | |
9c96033c | 2596 | { |
2597 | if (value) | |
2598 | return value; | |
2599 | else | |
2600 | /* We're in the middle of initializing it. */ | |
2601 | break; | |
2602 | } | |
09b42213 | 2603 | } |
2604 | if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE | |
2605 | && CONSTRUCTOR_NELTS (whole) > 0) | |
2606 | { | |
2607 | /* DR 1188 says we don't have to deal with this. */ | |
f83e6885 | 2608 | if (!ctx->quiet) |
09b42213 | 2609 | error ("accessing %qD member instead of initialized %qD member in " |
2610 | "constant expression", part, CONSTRUCTOR_ELT (whole, 0)->index); | |
2611 | *non_constant_p = true; | |
2612 | return t; | |
2613 | } | |
2614 | ||
f894a056 | 2615 | /* We only create a CONSTRUCTOR for a subobject when we modify it, so empty |
2616 | classes never get represented; throw together a value now. */ | |
2617 | if (is_really_empty_class (TREE_TYPE (t))) | |
2618 | return build_constructor (TREE_TYPE (t), NULL); | |
2619 | ||
a4360e57 | 2620 | gcc_assert (DECL_CONTEXT (part) == TYPE_MAIN_VARIANT (TREE_TYPE (whole))); |
2621 | ||
165d0d5b | 2622 | if (CONSTRUCTOR_NO_CLEARING (whole)) |
cf72f34d | 2623 | { |
2624 | /* 'whole' is part of the aggregate initializer we're currently | |
2625 | building; if there's no initializer for this member yet, that's an | |
f894a056 | 2626 | error. */ |
f83e6885 | 2627 | if (!ctx->quiet) |
cf72f34d | 2628 | error ("accessing uninitialized member %qD", part); |
2629 | *non_constant_p = true; | |
2630 | return t; | |
2631 | } | |
2632 | ||
09b42213 | 2633 | /* If there's no explicit init for this field, it's value-initialized. */ |
2634 | value = build_value_init (TREE_TYPE (t), tf_warning_or_error); | |
cf72f34d | 2635 | return cxx_eval_constant_expression (ctx, value, |
1227ba74 | 2636 | lval, |
b2a43197 | 2637 | non_constant_p, overflow_p); |
09b42213 | 2638 | } |
2639 | ||
2640 | /* Subroutine of cxx_eval_constant_expression. | |
2641 | Attempt to reduce a field access of a value of class type that is | |
2642 | expressed as a BIT_FIELD_REF. */ | |
2643 | ||
2644 | static tree | |
cf72f34d | 2645 | cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2646 | bool lval, |
09b42213 | 2647 | bool *non_constant_p, bool *overflow_p) |
2648 | { | |
2649 | tree orig_whole = TREE_OPERAND (t, 0); | |
2650 | tree retval, fldval, utype, mask; | |
2651 | bool fld_seen = false; | |
2652 | HOST_WIDE_INT istart, isize; | |
cf72f34d | 2653 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2654 | lval, |
b2a43197 | 2655 | non_constant_p, overflow_p); |
09b42213 | 2656 | tree start, field, value; |
2657 | unsigned HOST_WIDE_INT i; | |
2658 | ||
2659 | if (whole == orig_whole) | |
2660 | return t; | |
2661 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2662 | CONSTRUCTOR. */ | |
2663 | if (!*non_constant_p | |
2664 | && TREE_CODE (whole) != VECTOR_CST | |
2665 | && TREE_CODE (whole) != CONSTRUCTOR) | |
2666 | { | |
f83e6885 | 2667 | if (!ctx->quiet) |
09b42213 | 2668 | error ("%qE is not a constant expression", orig_whole); |
2669 | *non_constant_p = true; | |
2670 | } | |
2671 | if (*non_constant_p) | |
2672 | return t; | |
2673 | ||
2674 | if (TREE_CODE (whole) == VECTOR_CST) | |
2675 | return fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole, | |
2676 | TREE_OPERAND (t, 1), TREE_OPERAND (t, 2)); | |
2677 | ||
2678 | start = TREE_OPERAND (t, 2); | |
2679 | istart = tree_to_shwi (start); | |
2680 | isize = tree_to_shwi (TREE_OPERAND (t, 1)); | |
2681 | utype = TREE_TYPE (t); | |
2682 | if (!TYPE_UNSIGNED (utype)) | |
2683 | utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1); | |
2684 | retval = build_int_cst (utype, 0); | |
2685 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
2686 | { | |
2687 | tree bitpos = bit_position (field); | |
2688 | if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1)) | |
2689 | return value; | |
2690 | if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE | |
2691 | && TREE_CODE (value) == INTEGER_CST | |
2692 | && tree_fits_shwi_p (bitpos) | |
2693 | && tree_fits_shwi_p (DECL_SIZE (field))) | |
2694 | { | |
2695 | HOST_WIDE_INT bit = tree_to_shwi (bitpos); | |
2696 | HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field)); | |
2697 | HOST_WIDE_INT shift; | |
2698 | if (bit >= istart && bit + sz <= istart + isize) | |
2699 | { | |
2700 | fldval = fold_convert (utype, value); | |
2701 | mask = build_int_cst_type (utype, -1); | |
2702 | mask = fold_build2 (LSHIFT_EXPR, utype, mask, | |
2703 | size_int (TYPE_PRECISION (utype) - sz)); | |
2704 | mask = fold_build2 (RSHIFT_EXPR, utype, mask, | |
2705 | size_int (TYPE_PRECISION (utype) - sz)); | |
2706 | fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask); | |
2707 | shift = bit - istart; | |
2708 | if (BYTES_BIG_ENDIAN) | |
2709 | shift = TYPE_PRECISION (utype) - shift - sz; | |
2710 | fldval = fold_build2 (LSHIFT_EXPR, utype, fldval, | |
2711 | size_int (shift)); | |
2712 | retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval); | |
2713 | fld_seen = true; | |
2714 | } | |
2715 | } | |
2716 | } | |
2717 | if (fld_seen) | |
2718 | return fold_convert (TREE_TYPE (t), retval); | |
2719 | gcc_unreachable (); | |
2720 | return error_mark_node; | |
2721 | } | |
2722 | ||
2723 | /* Subroutine of cxx_eval_constant_expression. | |
2724 | Evaluate a short-circuited logical expression T in the context | |
2725 | of a given constexpr CALL. BAILOUT_VALUE is the value for | |
2726 | early return. CONTINUE_VALUE is used here purely for | |
2727 | sanity check purposes. */ | |
2728 | ||
2729 | static tree | |
cf72f34d | 2730 | cxx_eval_logical_expression (const constexpr_ctx *ctx, tree t, |
09b42213 | 2731 | tree bailout_value, tree continue_value, |
1227ba74 | 2732 | bool lval, |
09b42213 | 2733 | bool *non_constant_p, bool *overflow_p) |
2734 | { | |
2735 | tree r; | |
cf72f34d | 2736 | tree lhs = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 2737 | lval, |
b2a43197 | 2738 | non_constant_p, overflow_p); |
09b42213 | 2739 | VERIFY_CONSTANT (lhs); |
2740 | if (tree_int_cst_equal (lhs, bailout_value)) | |
2741 | return lhs; | |
2742 | gcc_assert (tree_int_cst_equal (lhs, continue_value)); | |
cf72f34d | 2743 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2744 | lval, non_constant_p, |
b2a43197 | 2745 | overflow_p); |
09b42213 | 2746 | VERIFY_CONSTANT (r); |
2747 | return r; | |
2748 | } | |
2749 | ||
2750 | /* REF is a COMPONENT_REF designating a particular field. V is a vector of | |
2751 | CONSTRUCTOR elements to initialize (part of) an object containing that | |
2752 | field. Return a pointer to the constructor_elt corresponding to the | |
2753 | initialization of the field. */ | |
2754 | ||
2755 | static constructor_elt * | |
2756 | base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref) | |
2757 | { | |
2758 | tree aggr = TREE_OPERAND (ref, 0); | |
2759 | tree field = TREE_OPERAND (ref, 1); | |
2760 | HOST_WIDE_INT i; | |
2761 | constructor_elt *ce; | |
2762 | ||
2763 | gcc_assert (TREE_CODE (ref) == COMPONENT_REF); | |
2764 | ||
2765 | if (TREE_CODE (aggr) == COMPONENT_REF) | |
2766 | { | |
2767 | constructor_elt *base_ce | |
2768 | = base_field_constructor_elt (v, aggr); | |
2769 | v = CONSTRUCTOR_ELTS (base_ce->value); | |
2770 | } | |
2771 | ||
2772 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2773 | if (ce->index == field) | |
2774 | return ce; | |
2775 | ||
2776 | gcc_unreachable (); | |
2777 | return NULL; | |
2778 | } | |
2779 | ||
cf72f34d | 2780 | /* Some of the expressions fed to the constexpr mechanism are calls to |
2781 | constructors, which have type void. In that case, return the type being | |
2782 | initialized by the constructor. */ | |
2783 | ||
2784 | static tree | |
2785 | initialized_type (tree t) | |
2786 | { | |
2787 | if (TYPE_P (t)) | |
2788 | return t; | |
59183fff | 2789 | tree type = TREE_TYPE (t); |
2790 | if (!VOID_TYPE_P (type)) | |
2791 | /* No need to look deeper. */; | |
2792 | else if (TREE_CODE (t) == CALL_EXPR) | |
cf72f34d | 2793 | { |
2794 | /* A constructor call has void type, so we need to look deeper. */ | |
2795 | tree fn = get_function_named_in_call (t); | |
2796 | if (fn && TREE_CODE (fn) == FUNCTION_DECL | |
2797 | && DECL_CXX_CONSTRUCTOR_P (fn)) | |
2798 | type = DECL_CONTEXT (fn); | |
2799 | } | |
59183fff | 2800 | else if (TREE_CODE (t) == AGGR_INIT_EXPR) |
2801 | type = TREE_TYPE (AGGR_INIT_EXPR_SLOT (t)); | |
2802 | return cv_unqualified (type); | |
cf72f34d | 2803 | } |
2804 | ||
2805 | /* We're about to initialize element INDEX of an array or class from VALUE. | |
2806 | Set up NEW_CTX appropriately by adjusting .object to refer to the | |
2807 | subobject and creating a new CONSTRUCTOR if the element is itself | |
2808 | a class or array. */ | |
2809 | ||
2810 | static void | |
2811 | init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, | |
2812 | tree index, tree &value) | |
2813 | { | |
2814 | new_ctx = *ctx; | |
2815 | ||
2816 | if (index && TREE_CODE (index) != INTEGER_CST | |
2817 | && TREE_CODE (index) != FIELD_DECL) | |
2818 | /* This won't have an element in the new CONSTRUCTOR. */ | |
2819 | return; | |
2820 | ||
2821 | tree type = initialized_type (value); | |
2822 | if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) | |
2823 | /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ | |
2824 | return; | |
2825 | ||
2826 | /* The sub-aggregate initializer might contain a placeholder; | |
2827 | update object to refer to the subobject and ctor to refer to | |
2828 | the (newly created) sub-initializer. */ | |
2829 | if (ctx->object) | |
2830 | new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); | |
2831 | tree elt = build_constructor (type, NULL); | |
165d0d5b | 2832 | CONSTRUCTOR_NO_CLEARING (elt) = true; |
cf72f34d | 2833 | new_ctx.ctor = elt; |
2834 | ||
2835 | if (TREE_CODE (value) == TARGET_EXPR) | |
2836 | /* Avoid creating another CONSTRUCTOR when we expand the TARGET_EXPR. */ | |
2837 | value = TARGET_EXPR_INITIAL (value); | |
2838 | } | |
2839 | ||
2840 | /* We're about to process an initializer for a class or array TYPE. Make | |
2841 | sure that CTX is set up appropriately. */ | |
2842 | ||
2843 | static void | |
2844 | verify_ctor_sanity (const constexpr_ctx *ctx, tree type) | |
2845 | { | |
2846 | /* We don't bother building a ctor for an empty base subobject. */ | |
2847 | if (is_empty_class (type)) | |
2848 | return; | |
2849 | ||
2850 | /* We're in the middle of an initializer that might involve placeholders; | |
2851 | our caller should have created a CONSTRUCTOR for us to put the | |
2852 | initializer into. We will either return that constructor or T. */ | |
2853 | gcc_assert (ctx->ctor); | |
2854 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2855 | (type, TREE_TYPE (ctx->ctor))); | |
bbf58224 | 2856 | /* We used to check that ctx->ctor was empty, but that isn't the case when |
2857 | the object is zero-initialized before calling the constructor. */ | |
cf72f34d | 2858 | if (ctx->object) |
d9751a3c | 2859 | { |
2860 | tree otype = TREE_TYPE (ctx->object); | |
2861 | gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, otype) | |
2862 | /* Handle flexible array members. */ | |
2863 | || (TREE_CODE (otype) == ARRAY_TYPE | |
2864 | && TYPE_DOMAIN (otype) == NULL_TREE | |
2865 | && TREE_CODE (type) == ARRAY_TYPE | |
2866 | && (same_type_ignoring_top_level_qualifiers_p | |
2867 | (TREE_TYPE (type), TREE_TYPE (otype))))); | |
2868 | } | |
cf72f34d | 2869 | gcc_assert (!ctx->object || !DECL_P (ctx->object) |
2870 | || *(ctx->values->get (ctx->object)) == ctx->ctor); | |
2871 | } | |
2872 | ||
09b42213 | 2873 | /* Subroutine of cxx_eval_constant_expression. |
2874 | The expression tree T denotes a C-style array or a C-style | |
2875 | aggregate. Reduce it to a constant expression. */ | |
2876 | ||
2877 | static tree | |
cf72f34d | 2878 | cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2879 | bool lval, |
09b42213 | 2880 | bool *non_constant_p, bool *overflow_p) |
2881 | { | |
2882 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
09b42213 | 2883 | bool changed = false; |
2884 | gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t)); | |
68464393 | 2885 | tree type = TREE_TYPE (t); |
cf72f34d | 2886 | |
68464393 | 2887 | constexpr_ctx new_ctx; |
d2dd85e3 | 2888 | if (TYPE_PTRMEMFUNC_P (type) || VECTOR_TYPE_P (type)) |
68464393 | 2889 | { |
d2dd85e3 | 2890 | /* We don't really need the ctx->ctor business for a PMF or |
2891 | vector, but it's simpler to use the same code. */ | |
68464393 | 2892 | new_ctx = *ctx; |
2893 | new_ctx.ctor = build_constructor (type, NULL); | |
2894 | new_ctx.object = NULL_TREE; | |
2895 | ctx = &new_ctx; | |
2896 | }; | |
2897 | verify_ctor_sanity (ctx, type); | |
cf72f34d | 2898 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); |
2899 | vec_alloc (*p, vec_safe_length (v)); | |
2900 | ||
58b0f9ce | 2901 | unsigned i; |
2902 | tree index, value; | |
2903 | bool constant_p = true; | |
2904 | bool side_effects_p = false; | |
cf72f34d | 2905 | FOR_EACH_CONSTRUCTOR_ELT (v, i, index, value) |
09b42213 | 2906 | { |
5ae773e4 | 2907 | tree orig_value = value; |
cf72f34d | 2908 | init_subob_ctx (ctx, new_ctx, index, value); |
2909 | if (new_ctx.ctor != ctx->ctor) | |
2910 | /* If we built a new CONSTRUCTOR, attach it now so that other | |
2911 | initializers can refer to it. */ | |
2912 | CONSTRUCTOR_APPEND_ELT (*p, index, new_ctx.ctor); | |
2913 | tree elt = cxx_eval_constant_expression (&new_ctx, value, | |
1227ba74 | 2914 | lval, |
b2a43197 | 2915 | non_constant_p, overflow_p); |
09b42213 | 2916 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 2917 | if (ctx->quiet && *non_constant_p) |
cf72f34d | 2918 | break; |
5ae773e4 | 2919 | if (elt != orig_value) |
09b42213 | 2920 | changed = true; |
58b0f9ce | 2921 | |
2922 | if (!TREE_CONSTANT (elt)) | |
2923 | constant_p = false; | |
2924 | if (TREE_SIDE_EFFECTS (elt)) | |
2925 | side_effects_p = true; | |
cf72f34d | 2926 | if (index && TREE_CODE (index) == COMPONENT_REF) |
09b42213 | 2927 | { |
2928 | /* This is an initialization of a vfield inside a base | |
2929 | subaggregate that we already initialized; push this | |
2930 | initialization into the previous initialization. */ | |
cf72f34d | 2931 | constructor_elt *inner = base_field_constructor_elt (*p, index); |
09b42213 | 2932 | inner->value = elt; |
cf72f34d | 2933 | changed = true; |
09b42213 | 2934 | } |
cf72f34d | 2935 | else if (index |
2936 | && (TREE_CODE (index) == NOP_EXPR | |
2937 | || TREE_CODE (index) == POINTER_PLUS_EXPR)) | |
09b42213 | 2938 | { |
2939 | /* This is an initializer for an empty base; now that we've | |
2940 | checked that it's constant, we can ignore it. */ | |
cf72f34d | 2941 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (index)))); |
2942 | changed = true; | |
2943 | } | |
09b42213 | 2944 | else |
79e65a6b | 2945 | { |
0dd49b5a | 2946 | if (new_ctx.ctor != ctx->ctor) |
2947 | { | |
2948 | /* We appended this element above; update the value. */ | |
2949 | gcc_assert ((*p)->last().index == index); | |
2950 | (*p)->last().value = elt; | |
2951 | } | |
2952 | else | |
2953 | CONSTRUCTOR_APPEND_ELT (*p, index, elt); | |
2954 | /* Adding or replacing an element might change the ctor's flags. */ | |
79e65a6b | 2955 | TREE_CONSTANT (ctx->ctor) = constant_p; |
2956 | TREE_SIDE_EFFECTS (ctx->ctor) = side_effects_p; | |
2957 | } | |
09b42213 | 2958 | } |
2959 | if (*non_constant_p || !changed) | |
cf72f34d | 2960 | return t; |
2961 | t = ctx->ctor; | |
2962 | /* We're done building this CONSTRUCTOR, so now we can interpret an | |
2963 | element without an explicit initializer as value-initialized. */ | |
165d0d5b | 2964 | CONSTRUCTOR_NO_CLEARING (t) = false; |
58b0f9ce | 2965 | TREE_CONSTANT (t) = constant_p; |
2966 | TREE_SIDE_EFFECTS (t) = side_effects_p; | |
68464393 | 2967 | if (VECTOR_TYPE_P (type)) |
09b42213 | 2968 | t = fold (t); |
2969 | return t; | |
2970 | } | |
2971 | ||
2972 | /* Subroutine of cxx_eval_constant_expression. | |
2973 | The expression tree T is a VEC_INIT_EXPR which denotes the desired | |
2974 | initialization of a non-static data member of array type. Reduce it to a | |
2975 | CONSTRUCTOR. | |
2976 | ||
2977 | Note that apart from value-initialization (when VALUE_INIT is true), | |
2978 | this is only intended to support value-initialization and the | |
2979 | initializations done by defaulted constructors for classes with | |
2980 | non-static data members of array type. In this case, VEC_INIT_EXPR_INIT | |
2981 | will either be NULL_TREE for the default constructor, or a COMPONENT_REF | |
2982 | for the copy/move constructor. */ | |
2983 | ||
2984 | static tree | |
cf72f34d | 2985 | cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, |
1227ba74 | 2986 | bool value_init, bool lval, |
09b42213 | 2987 | bool *non_constant_p, bool *overflow_p) |
2988 | { | |
2989 | tree elttype = TREE_TYPE (atype); | |
cf72f34d | 2990 | verify_ctor_sanity (ctx, atype); |
2991 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
09b42213 | 2992 | bool pre_init = false; |
3e520b97 | 2993 | unsigned HOST_WIDE_INT i; |
c4970310 | 2994 | tsubst_flags_t complain = ctx->quiet ? tf_none : tf_warning_or_error; |
09b42213 | 2995 | |
2996 | /* For the default constructor, build up a call to the default | |
2997 | constructor of the element type. We only need to handle class types | |
2998 | here, as for a constructor to be constexpr, all members must be | |
2999 | initialized, which for a defaulted default constructor means they must | |
3000 | be of a class type with a constexpr default constructor. */ | |
3001 | if (TREE_CODE (elttype) == ARRAY_TYPE) | |
3002 | /* We only do this at the lowest level. */; | |
3003 | else if (value_init) | |
3004 | { | |
c4970310 | 3005 | init = build_value_init (elttype, complain); |
09b42213 | 3006 | pre_init = true; |
3007 | } | |
3008 | else if (!init) | |
3009 | { | |
3010 | vec<tree, va_gc> *argvec = make_tree_vector (); | |
3011 | init = build_special_member_call (NULL_TREE, complete_ctor_identifier, | |
3012 | &argvec, elttype, LOOKUP_NORMAL, | |
c4970310 | 3013 | complain); |
09b42213 | 3014 | release_tree_vector (argvec); |
59183fff | 3015 | init = build_aggr_init_expr (elttype, init); |
09b42213 | 3016 | pre_init = true; |
3017 | } | |
3018 | ||
51f0c7e2 | 3019 | tree nelts = get_array_or_vector_nelts (ctx, atype, non_constant_p, |
3020 | overflow_p); | |
3021 | unsigned HOST_WIDE_INT max = tree_to_uhwi (nelts); | |
3e520b97 | 3022 | for (i = 0; i < max; ++i) |
09b42213 | 3023 | { |
3024 | tree idx = build_int_cst (size_type_node, i); | |
3025 | tree eltinit; | |
d9377ad5 | 3026 | bool reuse = false; |
cf72f34d | 3027 | constexpr_ctx new_ctx; |
3028 | init_subob_ctx (ctx, new_ctx, idx, pre_init ? init : elttype); | |
3029 | if (new_ctx.ctor != ctx->ctor) | |
3030 | CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor); | |
09b42213 | 3031 | if (TREE_CODE (elttype) == ARRAY_TYPE) |
3032 | { | |
3033 | /* A multidimensional array; recurse. */ | |
3034 | if (value_init || init == NULL_TREE) | |
d9377ad5 | 3035 | { |
3036 | eltinit = NULL_TREE; | |
3037 | reuse = i == 0; | |
3038 | } | |
09b42213 | 3039 | else |
c4970310 | 3040 | eltinit = cp_build_array_ref (input_location, init, idx, complain); |
cf72f34d | 3041 | eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, value_init, |
1227ba74 | 3042 | lval, |
09b42213 | 3043 | non_constant_p, overflow_p); |
3044 | } | |
3045 | else if (pre_init) | |
3046 | { | |
3047 | /* Initializing an element using value or default initialization | |
3048 | we just pre-built above. */ | |
0e9064d2 | 3049 | if (init == void_node) |
3050 | /* Trivial default-init, don't do anything to the CONSTRUCTOR. */ | |
3051 | return ctx->ctor; | |
d9377ad5 | 3052 | eltinit = cxx_eval_constant_expression (&new_ctx, init, lval, |
3053 | non_constant_p, overflow_p); | |
3054 | reuse = i == 0; | |
09b42213 | 3055 | } |
3056 | else | |
3057 | { | |
3058 | /* Copying an element. */ | |
3059 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
3060 | (atype, TREE_TYPE (init))); | |
c4970310 | 3061 | eltinit = cp_build_array_ref (input_location, init, idx, complain); |
18bede74 | 3062 | if (!lvalue_p (init)) |
09b42213 | 3063 | eltinit = move (eltinit); |
c4970310 | 3064 | eltinit = force_rvalue (eltinit, complain); |
eb7c25cc | 3065 | eltinit = cxx_eval_constant_expression (&new_ctx, eltinit, lval, |
3066 | non_constant_p, overflow_p); | |
09b42213 | 3067 | } |
f83e6885 | 3068 | if (*non_constant_p && !ctx->quiet) |
cf72f34d | 3069 | break; |
3070 | if (new_ctx.ctor != ctx->ctor) | |
3071 | { | |
3072 | /* We appended this element above; update the value. */ | |
3073 | gcc_assert ((*p)->last().index == idx); | |
3074 | (*p)->last().value = eltinit; | |
3075 | } | |
3076 | else | |
3077 | CONSTRUCTOR_APPEND_ELT (*p, idx, eltinit); | |
d9377ad5 | 3078 | /* Reuse the result of cxx_eval_constant_expression call |
eb7c25cc | 3079 | from the first iteration to all others if it is a constant |
3080 | initializer that doesn't require relocations. */ | |
d9377ad5 | 3081 | if (reuse |
3082 | && max > 1 | |
eb7c25cc | 3083 | && (eltinit == NULL_TREE |
3084 | || (initializer_constant_valid_p (eltinit, TREE_TYPE (eltinit)) | |
3085 | == null_pointer_node))) | |
d9377ad5 | 3086 | { |
3087 | if (new_ctx.ctor != ctx->ctor) | |
3088 | eltinit = new_ctx.ctor; | |
228a2cd8 | 3089 | tree range = build2 (RANGE_EXPR, size_type_node, |
3090 | build_int_cst (size_type_node, 1), | |
3091 | build_int_cst (size_type_node, max - 1)); | |
3092 | CONSTRUCTOR_APPEND_ELT (*p, range, unshare_constructor (eltinit)); | |
d9377ad5 | 3093 | break; |
3094 | } | |
228a2cd8 | 3095 | else if (i == 0) |
3096 | vec_safe_reserve (*p, max); | |
09b42213 | 3097 | } |
3098 | ||
3099 | if (!*non_constant_p) | |
3100 | { | |
cf72f34d | 3101 | init = ctx->ctor; |
165d0d5b | 3102 | CONSTRUCTOR_NO_CLEARING (init) = false; |
09b42213 | 3103 | } |
09b42213 | 3104 | return init; |
3105 | } | |
3106 | ||
3107 | static tree | |
cf72f34d | 3108 | cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3109 | bool lval, |
09b42213 | 3110 | bool *non_constant_p, bool *overflow_p) |
3111 | { | |
3112 | tree atype = TREE_TYPE (t); | |
3113 | tree init = VEC_INIT_EXPR_INIT (t); | |
cf72f34d | 3114 | tree r = cxx_eval_vec_init_1 (ctx, atype, init, |
09b42213 | 3115 | VEC_INIT_EXPR_VALUE_INIT (t), |
1227ba74 | 3116 | lval, non_constant_p, overflow_p); |
09b42213 | 3117 | if (*non_constant_p) |
3118 | return t; | |
3119 | else | |
3120 | return r; | |
3121 | } | |
3122 | ||
6b53d686 | 3123 | /* Like same_type_ignoring_top_level_qualifiers_p, but also handle the case |
3124 | where the desired type is an array of unknown bounds because the variable | |
3125 | has had its bounds deduced since the wrapping expression was created. */ | |
3126 | ||
3127 | static bool | |
3128 | same_type_ignoring_tlq_and_bounds_p (tree type1, tree type2) | |
3129 | { | |
3130 | while (TREE_CODE (type1) == ARRAY_TYPE | |
3131 | && TREE_CODE (type2) == ARRAY_TYPE | |
3132 | && (!TYPE_DOMAIN (type1) || !TYPE_DOMAIN (type2))) | |
3133 | { | |
3134 | type1 = TREE_TYPE (type1); | |
3135 | type2 = TREE_TYPE (type2); | |
3136 | } | |
3137 | return same_type_ignoring_top_level_qualifiers_p (type1, type2); | |
3138 | } | |
3139 | ||
09b42213 | 3140 | /* A less strict version of fold_indirect_ref_1, which requires cv-quals to |
3141 | match. We want to be less strict for simple *& folding; if we have a | |
3142 | non-const temporary that we access through a const pointer, that should | |
3143 | work. We handle this here rather than change fold_indirect_ref_1 | |
3144 | because we're dealing with things like ADDR_EXPR of INTEGER_CST which | |
3145 | don't really make sense outside of constant expression evaluation. Also | |
3146 | we want to allow folding to COMPONENT_REF, which could cause trouble | |
3147 | with TBAA in fold_indirect_ref_1. | |
3148 | ||
3149 | Try to keep this function synced with fold_indirect_ref_1. */ | |
3150 | ||
3151 | static tree | |
3152 | cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) | |
3153 | { | |
7d8e655d | 3154 | tree sub = op0; |
3155 | tree subtype; | |
3156 | poly_uint64 const_op01; | |
09b42213 | 3157 | |
09b42213 | 3158 | STRIP_NOPS (sub); |
3159 | subtype = TREE_TYPE (sub); | |
d03fa520 | 3160 | if (!INDIRECT_TYPE_P (subtype)) |
09b42213 | 3161 | return NULL_TREE; |
3162 | ||
3163 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3164 | { | |
3165 | tree op = TREE_OPERAND (sub, 0); | |
3166 | tree optype = TREE_TYPE (op); | |
3167 | ||
3168 | /* *&CONST_DECL -> to the value of the const decl. */ | |
3169 | if (TREE_CODE (op) == CONST_DECL) | |
3170 | return DECL_INITIAL (op); | |
3171 | /* *&p => p; make sure to handle *&"str"[cst] here. */ | |
6b53d686 | 3172 | if (same_type_ignoring_tlq_and_bounds_p (optype, type)) |
09b42213 | 3173 | { |
3174 | tree fop = fold_read_from_constant_string (op); | |
3175 | if (fop) | |
3176 | return fop; | |
3177 | else | |
3178 | return op; | |
3179 | } | |
3180 | /* *(foo *)&fooarray => fooarray[0] */ | |
3181 | else if (TREE_CODE (optype) == ARRAY_TYPE | |
3182 | && (same_type_ignoring_top_level_qualifiers_p | |
3183 | (type, TREE_TYPE (optype)))) | |
3184 | { | |
3185 | tree type_domain = TYPE_DOMAIN (optype); | |
3186 | tree min_val = size_zero_node; | |
3187 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3188 | min_val = TYPE_MIN_VALUE (type_domain); | |
3189 | return build4_loc (loc, ARRAY_REF, type, op, min_val, | |
3190 | NULL_TREE, NULL_TREE); | |
3191 | } | |
3192 | /* *(foo *)&complexfoo => __real__ complexfoo */ | |
3193 | else if (TREE_CODE (optype) == COMPLEX_TYPE | |
3194 | && (same_type_ignoring_top_level_qualifiers_p | |
3195 | (type, TREE_TYPE (optype)))) | |
3196 | return fold_build1_loc (loc, REALPART_EXPR, type, op); | |
3197 | /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3198 | else if (VECTOR_TYPE_P (optype) |
09b42213 | 3199 | && (same_type_ignoring_top_level_qualifiers_p |
3200 | (type, TREE_TYPE (optype)))) | |
3201 | { | |
3202 | tree part_width = TYPE_SIZE (type); | |
3203 | tree index = bitsize_int (0); | |
7d8e655d | 3204 | return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, |
3205 | index); | |
09b42213 | 3206 | } |
3207 | /* Also handle conversion to an empty base class, which | |
3208 | is represented with a NOP_EXPR. */ | |
3209 | else if (is_empty_class (type) | |
3210 | && CLASS_TYPE_P (optype) | |
3211 | && DERIVED_FROM_P (type, optype)) | |
3212 | { | |
3213 | *empty_base = true; | |
3214 | return op; | |
3215 | } | |
3216 | /* *(foo *)&struct_with_foo_field => COMPONENT_REF */ | |
3217 | else if (RECORD_OR_UNION_TYPE_P (optype)) | |
3218 | { | |
3219 | tree field = TYPE_FIELDS (optype); | |
3220 | for (; field; field = DECL_CHAIN (field)) | |
3221 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3222 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3223 | && integer_zerop (byte_position (field)) |
3224 | && (same_type_ignoring_top_level_qualifiers_p | |
3225 | (TREE_TYPE (field), type))) | |
a48667ee | 3226 | return fold_build3 (COMPONENT_REF, type, op, field, NULL_TREE); |
09b42213 | 3227 | } |
3228 | } | |
3229 | else if (TREE_CODE (sub) == POINTER_PLUS_EXPR | |
7d8e655d | 3230 | && poly_int_tree_p (TREE_OPERAND (sub, 1), &const_op01)) |
09b42213 | 3231 | { |
3232 | tree op00 = TREE_OPERAND (sub, 0); | |
3233 | tree op01 = TREE_OPERAND (sub, 1); | |
3234 | ||
3235 | STRIP_NOPS (op00); | |
3236 | if (TREE_CODE (op00) == ADDR_EXPR) | |
3237 | { | |
3238 | tree op00type; | |
3239 | op00 = TREE_OPERAND (op00, 0); | |
3240 | op00type = TREE_TYPE (op00); | |
3241 | ||
3242 | /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3243 | if (VECTOR_TYPE_P (op00type) |
7d8e655d | 3244 | && same_type_ignoring_top_level_qualifiers_p |
3245 | (type, TREE_TYPE (op00type)) | |
3246 | /* POINTER_PLUS_EXPR second operand is sizetype, unsigned, | |
3247 | but we want to treat offsets with MSB set as negative. | |
3248 | For the code below negative offsets are invalid and | |
3249 | TYPE_SIZE of the element is something unsigned, so | |
3250 | check whether op01 fits into poly_int64, which implies | |
3251 | it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and | |
3252 | then just use poly_uint64 because we want to treat the | |
3253 | value as unsigned. */ | |
3254 | && tree_fits_poly_int64_p (op01)) | |
09b42213 | 3255 | { |
09b42213 | 3256 | tree part_width = TYPE_SIZE (type); |
7d8e655d | 3257 | poly_uint64 max_offset |
3258 | = (tree_to_uhwi (part_width) / BITS_PER_UNIT | |
3259 | * TYPE_VECTOR_SUBPARTS (op00type)); | |
3260 | if (known_lt (const_op01, max_offset)) | |
3261 | { | |
3262 | tree index = bitsize_int (const_op01 * BITS_PER_UNIT); | |
3263 | return fold_build3_loc (loc, | |
3264 | BIT_FIELD_REF, type, op00, | |
3265 | part_width, index); | |
3266 | } | |
09b42213 | 3267 | } |
3268 | /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ | |
3269 | else if (TREE_CODE (op00type) == COMPLEX_TYPE | |
3270 | && (same_type_ignoring_top_level_qualifiers_p | |
3271 | (type, TREE_TYPE (op00type)))) | |
3272 | { | |
7d8e655d | 3273 | if (known_eq (wi::to_poly_offset (TYPE_SIZE_UNIT (type)), |
3274 | const_op01)) | |
09b42213 | 3275 | return fold_build1_loc (loc, IMAGPART_EXPR, type, op00); |
3276 | } | |
3277 | /* ((foo *)&fooarray)[1] => fooarray[1] */ | |
3278 | else if (TREE_CODE (op00type) == ARRAY_TYPE | |
3279 | && (same_type_ignoring_top_level_qualifiers_p | |
3280 | (type, TREE_TYPE (op00type)))) | |
3281 | { | |
3282 | tree type_domain = TYPE_DOMAIN (op00type); | |
3283 | tree min_val = size_zero_node; | |
3284 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3285 | min_val = TYPE_MIN_VALUE (type_domain); | |
53fa96c0 | 3286 | offset_int off = wi::to_offset (op01); |
3287 | offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type)); | |
3288 | offset_int remainder; | |
3289 | off = wi::divmod_trunc (off, el_sz, SIGNED, &remainder); | |
3290 | if (remainder == 0 && TREE_CODE (min_val) == INTEGER_CST) | |
3291 | { | |
3292 | off = off + wi::to_offset (min_val); | |
3293 | op01 = wide_int_to_tree (sizetype, off); | |
3294 | return build4_loc (loc, ARRAY_REF, type, op00, op01, | |
3295 | NULL_TREE, NULL_TREE); | |
3296 | } | |
09b42213 | 3297 | } |
3298 | /* Also handle conversion to an empty base class, which | |
3299 | is represented with a NOP_EXPR. */ | |
3300 | else if (is_empty_class (type) | |
3301 | && CLASS_TYPE_P (op00type) | |
3302 | && DERIVED_FROM_P (type, op00type)) | |
3303 | { | |
3304 | *empty_base = true; | |
3305 | return op00; | |
3306 | } | |
3307 | /* ((foo *)&struct_with_foo_field)[1] => COMPONENT_REF */ | |
3308 | else if (RECORD_OR_UNION_TYPE_P (op00type)) | |
3309 | { | |
3310 | tree field = TYPE_FIELDS (op00type); | |
3311 | for (; field; field = DECL_CHAIN (field)) | |
3312 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3313 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3314 | && tree_int_cst_equal (byte_position (field), op01) |
3315 | && (same_type_ignoring_top_level_qualifiers_p | |
3316 | (TREE_TYPE (field), type))) | |
a48667ee | 3317 | return fold_build3 (COMPONENT_REF, type, op00, |
3318 | field, NULL_TREE); | |
09b42213 | 3319 | } |
3320 | } | |
3321 | } | |
3322 | /* *(foo *)fooarrptr => (*fooarrptr)[0] */ | |
3323 | else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE | |
3324 | && (same_type_ignoring_top_level_qualifiers_p | |
3325 | (type, TREE_TYPE (TREE_TYPE (subtype))))) | |
3326 | { | |
3327 | tree type_domain; | |
3328 | tree min_val = size_zero_node; | |
7d8e655d | 3329 | tree newsub |
3330 | = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL); | |
09b42213 | 3331 | if (newsub) |
3332 | sub = newsub; | |
3333 | else | |
3334 | sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub); | |
3335 | type_domain = TYPE_DOMAIN (TREE_TYPE (sub)); | |
3336 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3337 | min_val = TYPE_MIN_VALUE (type_domain); | |
3338 | return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE, | |
3339 | NULL_TREE); | |
3340 | } | |
3341 | ||
3342 | return NULL_TREE; | |
3343 | } | |
3344 | ||
3345 | static tree | |
cf72f34d | 3346 | cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3347 | bool lval, |
09b42213 | 3348 | bool *non_constant_p, bool *overflow_p) |
3349 | { | |
3350 | tree orig_op0 = TREE_OPERAND (t, 0); | |
09b42213 | 3351 | bool empty_base = false; |
09b42213 | 3352 | |
d2c63826 | 3353 | /* We can handle a MEM_REF like an INDIRECT_REF, if MEM_REF's second |
3354 | operand is an integer-zero. Otherwise reject the MEM_REF for now. */ | |
3355 | ||
3356 | if (TREE_CODE (t) == MEM_REF | |
3357 | && (!TREE_OPERAND (t, 1) || !integer_zerop (TREE_OPERAND (t, 1)))) | |
3358 | { | |
3359 | gcc_assert (ctx->quiet); | |
3360 | *non_constant_p = true; | |
3361 | return t; | |
3362 | } | |
3363 | ||
7e0f3388 | 3364 | /* First try to simplify it directly. */ |
3365 | tree r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), orig_op0, | |
3366 | &empty_base); | |
3367 | if (!r) | |
09b42213 | 3368 | { |
7e0f3388 | 3369 | /* If that didn't work, evaluate the operand first. */ |
3370 | tree op0 = cxx_eval_constant_expression (ctx, orig_op0, | |
3371 | /*lval*/false, non_constant_p, | |
3372 | overflow_p); | |
3373 | /* Don't VERIFY_CONSTANT here. */ | |
3374 | if (*non_constant_p) | |
3375 | return t; | |
3376 | ||
cb768824 | 3377 | if (!lval && integer_zerop (op0)) |
3378 | { | |
3379 | if (!ctx->quiet) | |
3380 | error ("dereferencing a null pointer"); | |
3381 | *non_constant_p = true; | |
3382 | return t; | |
3383 | } | |
3384 | ||
7e0f3388 | 3385 | r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), op0, |
3386 | &empty_base); | |
3387 | if (r == NULL_TREE) | |
09b42213 | 3388 | { |
3389 | /* We couldn't fold to a constant value. Make sure it's not | |
3390 | something we should have been able to fold. */ | |
7e0f3388 | 3391 | tree sub = op0; |
3392 | STRIP_NOPS (sub); | |
3393 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3394 | { | |
3395 | gcc_assert (!same_type_ignoring_top_level_qualifiers_p | |
3396 | (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t))); | |
3397 | /* DR 1188 says we don't have to deal with this. */ | |
3398 | if (!ctx->quiet) | |
3399 | error ("accessing value of %qE through a %qT glvalue in a " | |
3400 | "constant expression", build_fold_indirect_ref (sub), | |
3401 | TREE_TYPE (t)); | |
3402 | *non_constant_p = true; | |
3403 | return t; | |
3404 | } | |
3405 | ||
3406 | if (lval && op0 != orig_op0) | |
3407 | return build1 (INDIRECT_REF, TREE_TYPE (t), op0); | |
3408 | if (!lval) | |
3409 | VERIFY_CONSTANT (t); | |
09b42213 | 3410 | return t; |
3411 | } | |
3412 | } | |
3413 | ||
7e0f3388 | 3414 | r = cxx_eval_constant_expression (ctx, r, |
3415 | lval, non_constant_p, overflow_p); | |
3416 | if (*non_constant_p) | |
3417 | return t; | |
3418 | ||
ce4ffd9e | 3419 | /* If we're pulling out the value of an empty base, just return an empty |
09b42213 | 3420 | CONSTRUCTOR. */ |
1227ba74 | 3421 | if (empty_base && !lval) |
09b42213 | 3422 | { |
09b42213 | 3423 | r = build_constructor (TREE_TYPE (t), NULL); |
3424 | TREE_CONSTANT (r) = true; | |
3425 | } | |
3426 | ||
09b42213 | 3427 | return r; |
3428 | } | |
3429 | ||
3430 | /* Complain about R, a VAR_DECL, not being usable in a constant expression. | |
3431 | Shared between potential_constant_expression and | |
3432 | cxx_eval_constant_expression. */ | |
3433 | ||
3434 | static void | |
3435 | non_const_var_error (tree r) | |
3436 | { | |
3437 | tree type = TREE_TYPE (r); | |
3438 | error ("the value of %qD is not usable in a constant " | |
3439 | "expression", r); | |
3440 | /* Avoid error cascade. */ | |
3441 | if (DECL_INITIAL (r) == error_mark_node) | |
3442 | return; | |
3443 | if (DECL_DECLARED_CONSTEXPR_P (r)) | |
3444 | inform (DECL_SOURCE_LOCATION (r), | |
3445 | "%qD used in its own initializer", r); | |
3446 | else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) | |
3447 | { | |
3448 | if (!CP_TYPE_CONST_P (type)) | |
3449 | inform (DECL_SOURCE_LOCATION (r), | |
3450 | "%q#D is not const", r); | |
3451 | else if (CP_TYPE_VOLATILE_P (type)) | |
3452 | inform (DECL_SOURCE_LOCATION (r), | |
3453 | "%q#D is volatile", r); | |
3454 | else if (!DECL_INITIAL (r) | |
c8e3e744 | 3455 | || !TREE_CONSTANT (DECL_INITIAL (r)) |
3456 | || !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (r)) | |
09b42213 | 3457 | inform (DECL_SOURCE_LOCATION (r), |
3458 | "%qD was not initialized with a constant " | |
3459 | "expression", r); | |
3460 | else | |
3461 | gcc_unreachable (); | |
3462 | } | |
90ad495b | 3463 | else if (TYPE_REF_P (type)) |
ac6641ca | 3464 | inform (DECL_SOURCE_LOCATION (r), |
3465 | "%qD was not initialized with a constant " | |
3466 | "expression", r); | |
09b42213 | 3467 | else |
3468 | { | |
3469 | if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r)) | |
3470 | inform (DECL_SOURCE_LOCATION (r), | |
3471 | "%qD was not declared %<constexpr%>", r); | |
3472 | else | |
3473 | inform (DECL_SOURCE_LOCATION (r), | |
3474 | "%qD does not have integral or enumeration type", | |
3475 | r); | |
3476 | } | |
3477 | } | |
3478 | ||
3479 | /* Subroutine of cxx_eval_constant_expression. | |
3480 | Like cxx_eval_unary_expression, except for trinary expressions. */ | |
3481 | ||
3482 | static tree | |
cf72f34d | 3483 | cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3484 | bool lval, |
09b42213 | 3485 | bool *non_constant_p, bool *overflow_p) |
3486 | { | |
3487 | int i; | |
3488 | tree args[3]; | |
3489 | tree val; | |
3490 | ||
3491 | for (i = 0; i < 3; i++) | |
3492 | { | |
cf72f34d | 3493 | args[i] = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, i), |
1227ba74 | 3494 | lval, |
b2a43197 | 3495 | non_constant_p, overflow_p); |
09b42213 | 3496 | VERIFY_CONSTANT (args[i]); |
3497 | } | |
3498 | ||
3499 | val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t), | |
3500 | args[0], args[1], args[2]); | |
3501 | if (val == NULL_TREE) | |
3502 | return t; | |
3503 | VERIFY_CONSTANT (val); | |
3504 | return val; | |
3505 | } | |
3506 | ||
33603066 | 3507 | /* True if T was declared in a function declared to be constexpr, and |
3508 | therefore potentially constant in C++14. */ | |
3509 | ||
09b42213 | 3510 | bool |
3511 | var_in_constexpr_fn (tree t) | |
3512 | { | |
3513 | tree ctx = DECL_CONTEXT (t); | |
33603066 | 3514 | return (ctx && TREE_CODE (ctx) == FUNCTION_DECL |
09b42213 | 3515 | && DECL_DECLARED_CONSTEXPR_P (ctx)); |
3516 | } | |
3517 | ||
33603066 | 3518 | /* True if T was declared in a function that might be constexpr: either a |
3519 | function that was declared constexpr, or a C++17 lambda op(). */ | |
3520 | ||
3521 | bool | |
3522 | var_in_maybe_constexpr_fn (tree t) | |
3523 | { | |
40e2decb | 3524 | if (cxx_dialect >= cxx17 |
33603066 | 3525 | && DECL_FUNCTION_SCOPE_P (t) |
3526 | && LAMBDA_FUNCTION_P (DECL_CONTEXT (t))) | |
3527 | return true; | |
3528 | return var_in_constexpr_fn (t); | |
3529 | } | |
3530 | ||
93312944 | 3531 | /* We're assigning INIT to TARGET. In do_build_copy_constructor and |
3532 | build_over_call we implement trivial copy of a class with tail padding using | |
3533 | assignment of character arrays, which is valid in normal code, but not in | |
3534 | constexpr evaluation. We don't need to worry about clobbering tail padding | |
3535 | in constexpr evaluation, so strip the type punning. */ | |
3536 | ||
3537 | static void | |
3538 | maybe_simplify_trivial_copy (tree &target, tree &init) | |
3539 | { | |
3540 | if (TREE_CODE (target) == MEM_REF | |
3541 | && TREE_CODE (init) == MEM_REF | |
3542 | && TREE_TYPE (target) == TREE_TYPE (init) | |
3543 | && TREE_CODE (TREE_TYPE (target)) == ARRAY_TYPE | |
3544 | && TREE_TYPE (TREE_TYPE (target)) == unsigned_char_type_node) | |
3545 | { | |
3546 | target = build_fold_indirect_ref (TREE_OPERAND (target, 0)); | |
3547 | init = build_fold_indirect_ref (TREE_OPERAND (init, 0)); | |
3548 | } | |
3549 | } | |
3550 | ||
9c96033c | 3551 | /* Evaluate an INIT_EXPR or MODIFY_EXPR. */ |
3552 | ||
3553 | static tree | |
3554 | cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3555 | bool lval, |
9c96033c | 3556 | bool *non_constant_p, bool *overflow_p) |
3557 | { | |
3558 | constexpr_ctx new_ctx = *ctx; | |
3559 | ||
8a36d0ec | 3560 | tree init = TREE_OPERAND (t, 1); |
3561 | if (TREE_CLOBBER_P (init)) | |
3562 | /* Just ignore clobbers. */ | |
3563 | return void_node; | |
3564 | ||
9c96033c | 3565 | /* First we figure out where we're storing to. */ |
3566 | tree target = TREE_OPERAND (t, 0); | |
93312944 | 3567 | |
3568 | maybe_simplify_trivial_copy (target, init); | |
3569 | ||
9db9fc38 | 3570 | tree type = TREE_TYPE (target); |
9c96033c | 3571 | target = cxx_eval_constant_expression (ctx, target, |
f83e6885 | 3572 | true, |
b2a43197 | 3573 | non_constant_p, overflow_p); |
9c96033c | 3574 | if (*non_constant_p) |
3575 | return t; | |
3576 | ||
cf3cefc9 | 3577 | /* cxx_eval_array_reference for lval = true allows references one past |
3578 | end of array, because it does not know if it is just taking address | |
3579 | (which is valid), or actual dereference. Here we know it is | |
3580 | a dereference, so diagnose it here. */ | |
3581 | for (tree probe = target; probe; ) | |
3582 | { | |
3583 | switch (TREE_CODE (probe)) | |
3584 | { | |
3585 | case ARRAY_REF: | |
3586 | tree nelts, ary; | |
3587 | ary = TREE_OPERAND (probe, 0); | |
51f0c7e2 | 3588 | nelts = get_array_or_vector_nelts (ctx, TREE_TYPE (ary), |
3589 | non_constant_p, overflow_p); | |
cf3cefc9 | 3590 | VERIFY_CONSTANT (nelts); |
3591 | gcc_assert (TREE_CODE (nelts) == INTEGER_CST | |
3592 | && TREE_CODE (TREE_OPERAND (probe, 1)) == INTEGER_CST); | |
cb7bca5f | 3593 | if (wi::to_widest (TREE_OPERAND (probe, 1)) == wi::to_widest (nelts)) |
cf3cefc9 | 3594 | { |
3595 | diag_array_subscript (ctx, ary, TREE_OPERAND (probe, 1)); | |
3596 | *non_constant_p = true; | |
3597 | return t; | |
3598 | } | |
3599 | /* FALLTHRU */ | |
3600 | ||
3601 | case BIT_FIELD_REF: | |
3602 | case COMPONENT_REF: | |
3603 | probe = TREE_OPERAND (probe, 0); | |
3604 | continue; | |
3605 | ||
3606 | default: | |
3607 | probe = NULL_TREE; | |
3608 | continue; | |
3609 | } | |
3610 | } | |
3611 | ||
9db9fc38 | 3612 | if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (target), type)) |
3613 | { | |
3614 | /* For initialization of an empty base, the original target will be | |
3615 | *(base*)this, which the above evaluation resolves to the object | |
3616 | argument, which has the derived type rather than the base type. In | |
3617 | this situation, just evaluate the initializer and return, since | |
3618 | there's no actual data to store. */ | |
3619 | gcc_assert (is_empty_class (type)); | |
3620 | return cxx_eval_constant_expression (ctx, init, false, | |
3621 | non_constant_p, overflow_p); | |
3622 | } | |
3623 | ||
9c96033c | 3624 | /* And then find the underlying variable. */ |
3625 | vec<tree,va_gc> *refs = make_tree_vector(); | |
3626 | tree object = NULL_TREE; | |
3627 | for (tree probe = target; object == NULL_TREE; ) | |
3628 | { | |
3629 | switch (TREE_CODE (probe)) | |
3630 | { | |
3631 | case BIT_FIELD_REF: | |
3632 | case COMPONENT_REF: | |
3633 | case ARRAY_REF: | |
3634 | vec_safe_push (refs, TREE_OPERAND (probe, 1)); | |
3635 | vec_safe_push (refs, TREE_TYPE (probe)); | |
3636 | probe = TREE_OPERAND (probe, 0); | |
3637 | break; | |
3638 | ||
3639 | default: | |
3640 | object = probe; | |
9c96033c | 3641 | } |
3642 | } | |
3643 | ||
3644 | /* And then find/build up our initializer for the path to the subobject | |
3645 | we're initializing. */ | |
6fe83e54 | 3646 | tree *valp; |
43b7271d | 3647 | if (object == ctx->object && VAR_P (object) |
3648 | && DECL_NAME (object) && ctx->call == NULL) | |
3649 | /* The variable we're building up an aggregate initializer for is outside | |
3650 | the constant-expression, so don't evaluate the store. We check | |
3651 | DECL_NAME to handle TARGET_EXPR temporaries, which are fair game. */ | |
3652 | valp = NULL; | |
3653 | else if (DECL_P (object)) | |
6fe83e54 | 3654 | valp = ctx->values->get (object); |
3655 | else | |
3656 | valp = NULL; | |
9c96033c | 3657 | if (!valp) |
3658 | { | |
3659 | /* A constant-expression cannot modify objects from outside the | |
3660 | constant-expression. */ | |
f83e6885 | 3661 | if (!ctx->quiet) |
ea034e2c | 3662 | error ("modification of %qE is not a constant expression", object); |
9c96033c | 3663 | *non_constant_p = true; |
3664 | return t; | |
3665 | } | |
9db9fc38 | 3666 | type = TREE_TYPE (object); |
a02b42fe | 3667 | bool no_zero_init = true; |
58b0f9ce | 3668 | |
3669 | vec<tree,va_gc> *ctors = make_tree_vector (); | |
9c96033c | 3670 | while (!refs->is_empty()) |
3671 | { | |
3672 | if (*valp == NULL_TREE) | |
3673 | { | |
3674 | *valp = build_constructor (type, NULL); | |
165d0d5b | 3675 | CONSTRUCTOR_NO_CLEARING (*valp) = no_zero_init; |
9c96033c | 3676 | } |
92fe8840 | 3677 | else if (TREE_CODE (*valp) == STRING_CST) |
3678 | { | |
3679 | /* An array was initialized with a string constant, and now | |
3680 | we're writing into one of its elements. Explode the | |
3681 | single initialization into a set of element | |
3682 | initializations. */ | |
3683 | gcc_assert (TREE_CODE (type) == ARRAY_TYPE); | |
3684 | ||
3685 | tree string = *valp; | |
3686 | tree elt_type = TREE_TYPE (type); | |
3687 | unsigned chars_per_elt = (TYPE_PRECISION (elt_type) | |
3688 | / TYPE_PRECISION (char_type_node)); | |
3689 | unsigned num_elts = TREE_STRING_LENGTH (string) / chars_per_elt; | |
3690 | tree ary_ctor = build_constructor (type, NULL); | |
3691 | ||
3692 | vec_safe_reserve (CONSTRUCTOR_ELTS (ary_ctor), num_elts); | |
3693 | for (unsigned ix = 0; ix != num_elts; ix++) | |
3694 | { | |
3695 | constructor_elt elt = | |
3696 | { | |
3697 | build_int_cst (size_type_node, ix), | |
3698 | extract_string_elt (string, chars_per_elt, ix) | |
3699 | }; | |
3700 | CONSTRUCTOR_ELTS (ary_ctor)->quick_push (elt); | |
3701 | } | |
3702 | ||
3703 | *valp = ary_ctor; | |
3704 | } | |
3705 | ||
a02b42fe | 3706 | /* If the value of object is already zero-initialized, any new ctors for |
3707 | subobjects will also be zero-initialized. */ | |
165d0d5b | 3708 | no_zero_init = CONSTRUCTOR_NO_CLEARING (*valp); |
9c96033c | 3709 | |
58b0f9ce | 3710 | vec_safe_push (ctors, *valp); |
3711 | ||
7963b19d | 3712 | enum tree_code code = TREE_CODE (type); |
9c96033c | 3713 | type = refs->pop(); |
7963b19d | 3714 | tree index = refs->pop(); |
9c96033c | 3715 | |
9c96033c | 3716 | constructor_elt *cep = NULL; |
7963b19d | 3717 | if (code == ARRAY_TYPE) |
3718 | { | |
3719 | HOST_WIDE_INT i | |
3720 | = find_array_ctor_elt (*valp, index, /*insert*/true); | |
3721 | gcc_assert (i >= 0); | |
3722 | cep = CONSTRUCTOR_ELT (*valp, i); | |
3723 | gcc_assert (TREE_CODE (cep->index) != RANGE_EXPR); | |
3724 | } | |
3725 | else | |
3726 | { | |
3727 | gcc_assert (TREE_CODE (index) == FIELD_DECL); | |
13ee2de7 | 3728 | |
3729 | /* We must keep the CONSTRUCTOR's ELTS in FIELD order. | |
3730 | Usually we meet initializers in that order, but it is | |
3731 | possible for base types to be placed not in program | |
3732 | order. */ | |
3733 | tree fields = TYPE_FIELDS (DECL_CONTEXT (index)); | |
3734 | unsigned HOST_WIDE_INT idx; | |
3735 | ||
ef782365 | 3736 | if (code == UNION_TYPE && CONSTRUCTOR_NELTS (*valp) |
3737 | && CONSTRUCTOR_ELT (*valp, 0)->index != index) | |
3738 | /* Changing active member. */ | |
3739 | vec_safe_truncate (CONSTRUCTOR_ELTS (*valp), 0); | |
3740 | ||
13ee2de7 | 3741 | for (idx = 0; |
7963b19d | 3742 | vec_safe_iterate (CONSTRUCTOR_ELTS (*valp), idx, &cep); |
13ee2de7 | 3743 | idx++, fields = DECL_CHAIN (fields)) |
7963b19d | 3744 | { |
13ee2de7 | 3745 | if (index == cep->index) |
3746 | goto found; | |
3747 | ||
3748 | /* The field we're initializing must be on the field | |
3749 | list. Look to see if it is present before the | |
3750 | field the current ELT initializes. */ | |
3751 | for (; fields != cep->index; fields = DECL_CHAIN (fields)) | |
3752 | if (index == fields) | |
3753 | goto insert; | |
7963b19d | 3754 | } |
13ee2de7 | 3755 | |
3756 | /* We fell off the end of the CONSTRUCTOR, so insert a new | |
3757 | entry at the end. */ | |
3758 | insert: | |
3759 | { | |
3760 | constructor_elt ce = { index, NULL_TREE }; | |
3761 | ||
3762 | vec_safe_insert (CONSTRUCTOR_ELTS (*valp), idx, ce); | |
3763 | cep = CONSTRUCTOR_ELT (*valp, idx); | |
3764 | } | |
3765 | found:; | |
7963b19d | 3766 | } |
9c96033c | 3767 | valp = &cep->value; |
3768 | } | |
3769 | release_tree_vector (refs); | |
3770 | ||
469dc5a6 | 3771 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) |
9c96033c | 3772 | { |
3773 | /* Create a new CONSTRUCTOR in case evaluation of the initializer | |
3774 | wants to modify it. */ | |
469dc5a6 | 3775 | if (*valp == NULL_TREE) |
6cded085 | 3776 | { |
6993e708 | 3777 | *valp = build_constructor (type, NULL); |
165d0d5b | 3778 | CONSTRUCTOR_NO_CLEARING (*valp) = no_zero_init; |
6cded085 | 3779 | } |
6993e708 | 3780 | else if (TREE_CODE (*valp) == PTRMEM_CST) |
3781 | *valp = cplus_expand_constant (*valp); | |
3782 | new_ctx.ctor = *valp; | |
9c96033c | 3783 | new_ctx.object = target; |
3784 | } | |
3785 | ||
8a36d0ec | 3786 | init = cxx_eval_constant_expression (&new_ctx, init, false, |
3787 | non_constant_p, overflow_p); | |
7b9f713d | 3788 | /* Don't share a CONSTRUCTOR that might be changed later. */ |
e283bb4f | 3789 | init = unshare_constructor (init); |
9c96033c | 3790 | if (target == object) |
5579a199 | 3791 | /* The hash table might have moved since the get earlier. */ |
3792 | valp = ctx->values->get (object); | |
3793 | ||
3794 | if (TREE_CODE (init) == CONSTRUCTOR) | |
469dc5a6 | 3795 | { |
5579a199 | 3796 | /* An outer ctx->ctor might be pointing to *valp, so replace |
3797 | its contents. */ | |
3798 | CONSTRUCTOR_ELTS (*valp) = CONSTRUCTOR_ELTS (init); | |
3799 | TREE_CONSTANT (*valp) = TREE_CONSTANT (init); | |
3800 | TREE_SIDE_EFFECTS (*valp) = TREE_SIDE_EFFECTS (init); | |
165d0d5b | 3801 | CONSTRUCTOR_NO_CLEARING (*valp) |
3802 | = CONSTRUCTOR_NO_CLEARING (init); | |
469dc5a6 | 3803 | } |
9c96033c | 3804 | else |
5579a199 | 3805 | *valp = init; |
58b0f9ce | 3806 | |
5579a199 | 3807 | /* Update TREE_CONSTANT and TREE_SIDE_EFFECTS on enclosing |
3808 | CONSTRUCTORs, if any. */ | |
3809 | tree elt; | |
3810 | unsigned i; | |
3811 | bool c = TREE_CONSTANT (init); | |
3812 | bool s = TREE_SIDE_EFFECTS (init); | |
3813 | if (!c || s) | |
3814 | FOR_EACH_VEC_SAFE_ELT (ctors, i, elt) | |
3815 | { | |
3816 | if (!c) | |
3817 | TREE_CONSTANT (elt) = false; | |
3818 | if (s) | |
3819 | TREE_SIDE_EFFECTS (elt) = true; | |
3820 | } | |
58b0f9ce | 3821 | release_tree_vector (ctors); |
9c96033c | 3822 | |
3823 | if (*non_constant_p) | |
3824 | return t; | |
1227ba74 | 3825 | else if (lval) |
9c96033c | 3826 | return target; |
3827 | else | |
dfac7dd2 | 3828 | return init; |
9c96033c | 3829 | } |
3830 | ||
3831 | /* Evaluate a ++ or -- expression. */ | |
3832 | ||
3833 | static tree | |
3834 | cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3835 | bool lval, |
9c96033c | 3836 | bool *non_constant_p, bool *overflow_p) |
3837 | { | |
3838 | enum tree_code code = TREE_CODE (t); | |
3839 | tree type = TREE_TYPE (t); | |
3840 | tree op = TREE_OPERAND (t, 0); | |
3841 | tree offset = TREE_OPERAND (t, 1); | |
3842 | gcc_assert (TREE_CONSTANT (offset)); | |
3843 | ||
3844 | /* The operand as an lvalue. */ | |
f83e6885 | 3845 | op = cxx_eval_constant_expression (ctx, op, true, |
b2a43197 | 3846 | non_constant_p, overflow_p); |
9c96033c | 3847 | |
3848 | /* The operand as an rvalue. */ | |
c017458d | 3849 | tree val |
3850 | = cxx_eval_constant_expression (ctx, op, false, | |
3851 | non_constant_p, overflow_p); | |
35f2c28f | 3852 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
3853 | a local array in a constexpr function. */ | |
d03fa520 | 3854 | bool ptr = INDIRECT_TYPE_P (TREE_TYPE (val)); |
35f2c28f | 3855 | if (!ptr) |
3856 | VERIFY_CONSTANT (val); | |
9c96033c | 3857 | |
3858 | /* The modified value. */ | |
3859 | bool inc = (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR); | |
c8a8f7ad | 3860 | tree mod; |
d03fa520 | 3861 | if (INDIRECT_TYPE_P (type)) |
c8a8f7ad | 3862 | { |
3863 | /* The middle end requires pointers to use POINTER_PLUS_EXPR. */ | |
3864 | offset = convert_to_ptrofftype (offset); | |
3865 | if (!inc) | |
3866 | offset = fold_build1 (NEGATE_EXPR, TREE_TYPE (offset), offset); | |
3867 | mod = fold_build2 (POINTER_PLUS_EXPR, type, val, offset); | |
3868 | } | |
3869 | else | |
3870 | mod = fold_build2 (inc ? PLUS_EXPR : MINUS_EXPR, type, val, offset); | |
35f2c28f | 3871 | if (!ptr) |
3872 | VERIFY_CONSTANT (mod); | |
9c96033c | 3873 | |
3874 | /* Storing the modified value. */ | |
3875 | tree store = build2 (MODIFY_EXPR, type, op, mod); | |
f83e6885 | 3876 | cxx_eval_constant_expression (ctx, store, |
b2a43197 | 3877 | true, non_constant_p, overflow_p); |
9c96033c | 3878 | |
3879 | /* And the value of the expression. */ | |
3880 | if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) | |
3881 | { | |
3882 | /* Prefix ops are lvalues. */ | |
1227ba74 | 3883 | if (lval) |
9c96033c | 3884 | return op; |
3885 | else | |
3886 | /* But we optimize when the caller wants an rvalue. */ | |
3887 | return mod; | |
3888 | } | |
3889 | else | |
3890 | /* Postfix ops are rvalues. */ | |
3891 | return val; | |
3892 | } | |
3893 | ||
00f21715 | 3894 | /* Predicates for the meaning of *jump_target. */ |
3895 | ||
3896 | static bool | |
3897 | returns (tree *jump_target) | |
3898 | { | |
3899 | return *jump_target | |
d29e4e8c | 3900 | && (TREE_CODE (*jump_target) == RETURN_EXPR |
3901 | || (TREE_CODE (*jump_target) == LABEL_DECL | |
3902 | && LABEL_DECL_CDTOR (*jump_target))); | |
00f21715 | 3903 | } |
3904 | ||
3905 | static bool | |
3906 | breaks (tree *jump_target) | |
3907 | { | |
3908 | return *jump_target | |
cf03ba19 | 3909 | && ((TREE_CODE (*jump_target) == LABEL_DECL |
3910 | && LABEL_DECL_BREAK (*jump_target)) | |
32fee334 | 3911 | || TREE_CODE (*jump_target) == BREAK_STMT |
cf03ba19 | 3912 | || TREE_CODE (*jump_target) == EXIT_EXPR); |
00f21715 | 3913 | } |
3914 | ||
3915 | static bool | |
3916 | continues (tree *jump_target) | |
3917 | { | |
3918 | return *jump_target | |
32fee334 | 3919 | && ((TREE_CODE (*jump_target) == LABEL_DECL |
3920 | && LABEL_DECL_CONTINUE (*jump_target)) | |
3921 | || TREE_CODE (*jump_target) == CONTINUE_STMT); | |
3922 | ||
00f21715 | 3923 | } |
3924 | ||
3925 | static bool | |
3926 | switches (tree *jump_target) | |
3927 | { | |
3928 | return *jump_target | |
3929 | && TREE_CODE (*jump_target) == INTEGER_CST; | |
3930 | } | |
3931 | ||
3932 | /* Subroutine of cxx_eval_statement_list. Determine whether the statement | |
2a2770c6 | 3933 | STMT matches *jump_target. If we're looking for a case label and we see |
3934 | the default label, note it in ctx->css_state. */ | |
00f21715 | 3935 | |
3936 | static bool | |
2a2770c6 | 3937 | label_matches (const constexpr_ctx *ctx, tree *jump_target, tree stmt) |
00f21715 | 3938 | { |
00f21715 | 3939 | switch (TREE_CODE (*jump_target)) |
3940 | { | |
3941 | case LABEL_DECL: | |
3942 | if (TREE_CODE (stmt) == LABEL_EXPR | |
3943 | && LABEL_EXPR_LABEL (stmt) == *jump_target) | |
3944 | return true; | |
3945 | break; | |
3946 | ||
3947 | case INTEGER_CST: | |
3948 | if (TREE_CODE (stmt) == CASE_LABEL_EXPR) | |
3949 | { | |
2a2770c6 | 3950 | gcc_assert (ctx->css_state != NULL); |
00f21715 | 3951 | if (!CASE_LOW (stmt)) |
2a2770c6 | 3952 | { |
3953 | /* default: should appear just once in a SWITCH_EXPR | |
3954 | body (excluding nested SWITCH_EXPR). */ | |
3955 | gcc_assert (*ctx->css_state != css_default_seen); | |
3956 | /* When evaluating SWITCH_EXPR body for the second time, | |
3957 | return true for the default: label. */ | |
3958 | if (*ctx->css_state == css_default_processing) | |
3959 | return true; | |
3960 | *ctx->css_state = css_default_seen; | |
3961 | } | |
83c375ba | 3962 | else if (CASE_HIGH (stmt)) |
3963 | { | |
3964 | if (tree_int_cst_le (CASE_LOW (stmt), *jump_target) | |
3965 | && tree_int_cst_le (*jump_target, CASE_HIGH (stmt))) | |
3966 | return true; | |
3967 | } | |
00f21715 | 3968 | else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt))) |
3969 | return true; | |
3970 | } | |
3971 | break; | |
3972 | ||
3973 | default: | |
3974 | gcc_unreachable (); | |
3975 | } | |
3976 | return false; | |
3977 | } | |
3978 | ||
3979 | /* Evaluate a STATEMENT_LIST for side-effects. Handles various jump | |
3980 | semantics, for switch, break, continue, and return. */ | |
3981 | ||
3982 | static tree | |
3983 | cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3984 | bool *non_constant_p, bool *overflow_p, |
3985 | tree *jump_target) | |
3986 | { | |
3987 | tree_stmt_iterator i; | |
da7981e0 | 3988 | tree local_target; |
efea7c64 | 3989 | /* In a statement-expression we want to return the last value. |
3990 | For empty statement expression return void_node. */ | |
3991 | tree r = void_node; | |
da7981e0 | 3992 | if (!jump_target) |
3993 | { | |
3994 | local_target = NULL_TREE; | |
3995 | jump_target = &local_target; | |
3996 | } | |
00f21715 | 3997 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) |
3998 | { | |
00f21715 | 3999 | tree stmt = tsi_stmt (i); |
ba0f90e4 | 4000 | /* We've found a continue, so skip everything until we reach |
4001 | the label its jumping to. */ | |
4002 | if (continues (jump_target)) | |
4003 | { | |
4004 | if (label_matches (ctx, jump_target, stmt)) | |
4005 | /* Found it. */ | |
4006 | *jump_target = NULL_TREE; | |
4007 | else | |
4008 | continue; | |
4009 | } | |
442c4003 | 4010 | if (TREE_CODE (stmt) == DEBUG_BEGIN_STMT) |
4011 | continue; | |
da7981e0 | 4012 | r = cxx_eval_constant_expression (ctx, stmt, false, |
4013 | non_constant_p, overflow_p, | |
4014 | jump_target); | |
00f21715 | 4015 | if (*non_constant_p) |
4016 | break; | |
4017 | if (returns (jump_target) || breaks (jump_target)) | |
4018 | break; | |
4019 | } | |
da7981e0 | 4020 | return r; |
00f21715 | 4021 | } |
4022 | ||
4023 | /* Evaluate a LOOP_EXPR for side-effects. Handles break and return | |
4024 | semantics; continue semantics are covered by cxx_eval_statement_list. */ | |
4025 | ||
4026 | static tree | |
4027 | cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 4028 | bool *non_constant_p, bool *overflow_p, |
4029 | tree *jump_target) | |
4030 | { | |
2631cb67 | 4031 | constexpr_ctx new_ctx = *ctx; |
4032 | ||
00f21715 | 4033 | tree body = TREE_OPERAND (t, 0); |
21483ab7 | 4034 | int count = 0; |
5370eb8d | 4035 | do |
00f21715 | 4036 | { |
2631cb67 | 4037 | hash_set<tree> save_exprs; |
4038 | new_ctx.save_exprs = &save_exprs; | |
4039 | ||
cf03ba19 | 4040 | cxx_eval_constant_expression (&new_ctx, body, /*lval*/false, |
4041 | non_constant_p, overflow_p, jump_target); | |
2631cb67 | 4042 | |
4043 | /* Forget saved values of SAVE_EXPRs. */ | |
4044 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
4045 | iter != save_exprs.end(); ++iter) | |
4046 | new_ctx.values->remove (*iter); | |
21483ab7 | 4047 | if (++count >= constexpr_loop_limit) |
4048 | { | |
4049 | if (!ctx->quiet) | |
d3a3cfb8 | 4050 | error_at (cp_expr_loc_or_loc (t, input_location), |
5967b28b | 4051 | "%<constexpr%> loop iteration count exceeds limit of %d " |
21483ab7 | 4052 | "(use -fconstexpr-loop-limit= to increase the limit)", |
4053 | constexpr_loop_limit); | |
4054 | *non_constant_p = true; | |
4055 | break; | |
4056 | } | |
00f21715 | 4057 | } |
2a2770c6 | 4058 | while (!returns (jump_target) |
4059 | && !breaks (jump_target) | |
4060 | && !switches (jump_target) | |
4061 | && !*non_constant_p); | |
5370eb8d | 4062 | |
00f21715 | 4063 | if (breaks (jump_target)) |
4064 | *jump_target = NULL_TREE; | |
2631cb67 | 4065 | |
00f21715 | 4066 | return NULL_TREE; |
4067 | } | |
4068 | ||
4069 | /* Evaluate a SWITCH_EXPR for side-effects. Handles switch and break jump | |
4070 | semantics. */ | |
4071 | ||
4072 | static tree | |
4073 | cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 4074 | bool *non_constant_p, bool *overflow_p, |
4075 | tree *jump_target) | |
4076 | { | |
4077 | tree cond = TREE_OPERAND (t, 0); | |
f83e6885 | 4078 | cond = cxx_eval_constant_expression (ctx, cond, false, |
b2a43197 | 4079 | non_constant_p, overflow_p); |
00f21715 | 4080 | VERIFY_CONSTANT (cond); |
4081 | *jump_target = cond; | |
4082 | ||
4083 | tree body = TREE_OPERAND (t, 1); | |
2a2770c6 | 4084 | constexpr_ctx new_ctx = *ctx; |
4085 | constexpr_switch_state css = css_default_not_seen; | |
4086 | new_ctx.css_state = &css; | |
4087 | cxx_eval_constant_expression (&new_ctx, body, false, | |
4088 | non_constant_p, overflow_p, jump_target); | |
4089 | if (switches (jump_target) && css == css_default_seen) | |
4090 | { | |
4091 | /* If the SWITCH_EXPR body has default: label, process it once again, | |
4092 | this time instructing label_matches to return true for default: | |
4093 | label on switches (jump_target). */ | |
4094 | css = css_default_processing; | |
4095 | cxx_eval_constant_expression (&new_ctx, body, false, | |
4096 | non_constant_p, overflow_p, jump_target); | |
4097 | } | |
00f21715 | 4098 | if (breaks (jump_target) || switches (jump_target)) |
4099 | *jump_target = NULL_TREE; | |
4100 | return NULL_TREE; | |
4101 | } | |
4102 | ||
85de9604 | 4103 | /* Find the object of TYPE under initialization in CTX. */ |
4104 | ||
4105 | static tree | |
4106 | lookup_placeholder (const constexpr_ctx *ctx, bool lval, tree type) | |
4107 | { | |
def8e41f | 4108 | if (!ctx) |
85de9604 | 4109 | return NULL_TREE; |
4110 | ||
4111 | /* We could use ctx->object unconditionally, but using ctx->ctor when we | |
4112 | can is a minor optimization. */ | |
def8e41f | 4113 | if (!lval && ctx->ctor && same_type_p (TREE_TYPE (ctx->ctor), type)) |
85de9604 | 4114 | return ctx->ctor; |
4115 | ||
def8e41f | 4116 | if (!ctx->object) |
4117 | return NULL_TREE; | |
4118 | ||
85de9604 | 4119 | /* Since an object cannot have a field of its own type, we can search outward |
4120 | from ctx->object to find the unique containing object of TYPE. */ | |
4121 | tree ob = ctx->object; | |
4122 | while (ob) | |
4123 | { | |
4124 | if (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (ob), type)) | |
4125 | break; | |
4126 | if (handled_component_p (ob)) | |
4127 | ob = TREE_OPERAND (ob, 0); | |
4128 | else | |
4129 | ob = NULL_TREE; | |
4130 | } | |
4131 | ||
4132 | return ob; | |
4133 | } | |
4134 | ||
09b42213 | 4135 | /* Attempt to reduce the expression T to a constant value. |
4136 | On failure, issue diagnostic and return error_mark_node. */ | |
4137 | /* FIXME unify with c_fully_fold */ | |
9c96033c | 4138 | /* FIXME overflow_p is too global */ |
09b42213 | 4139 | |
4140 | static tree | |
cf72f34d | 4141 | cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 4142 | bool lval, |
00f21715 | 4143 | bool *non_constant_p, bool *overflow_p, |
32fee334 | 4144 | tree *jump_target /* = NULL */) |
09b42213 | 4145 | { |
cf72f34d | 4146 | constexpr_ctx new_ctx; |
09b42213 | 4147 | tree r = t; |
4148 | ||
2a2770c6 | 4149 | if (jump_target && *jump_target) |
4150 | { | |
4151 | /* If we are jumping, ignore all statements/expressions except those | |
4152 | that could have LABEL_EXPR or CASE_LABEL_EXPR in their bodies. */ | |
4153 | switch (TREE_CODE (t)) | |
4154 | { | |
4155 | case BIND_EXPR: | |
4156 | case STATEMENT_LIST: | |
4157 | case LOOP_EXPR: | |
4158 | case COND_EXPR: | |
4159 | break; | |
4160 | case LABEL_EXPR: | |
4161 | case CASE_LABEL_EXPR: | |
4162 | if (label_matches (ctx, jump_target, t)) | |
4163 | /* Found it. */ | |
4164 | *jump_target = NULL_TREE; | |
4165 | return NULL_TREE; | |
4166 | default: | |
4167 | return NULL_TREE; | |
4168 | } | |
4169 | } | |
32fee334 | 4170 | if (error_operand_p (t)) |
09b42213 | 4171 | { |
4172 | *non_constant_p = true; | |
4173 | return t; | |
4174 | } | |
4175 | if (CONSTANT_CLASS_P (t)) | |
4176 | { | |
c4fa85c9 | 4177 | if (TREE_OVERFLOW (t)) |
4178 | { | |
4179 | if (!ctx->quiet) | |
4180 | permerror (input_location, "overflow in constant expression"); | |
4181 | if (!flag_permissive || ctx->quiet) | |
4182 | *overflow_p = true; | |
4183 | } | |
cb768824 | 4184 | |
4185 | if (TREE_CODE (t) == INTEGER_CST | |
90ad495b | 4186 | && TYPE_PTR_P (TREE_TYPE (t)) |
cb768824 | 4187 | && !integer_zerop (t)) |
4188 | { | |
4189 | if (!ctx->quiet) | |
4190 | error ("value %qE of type %qT is not a constant expression", | |
4191 | t, TREE_TYPE (t)); | |
4192 | *non_constant_p = true; | |
4193 | } | |
4194 | ||
09b42213 | 4195 | return t; |
4196 | } | |
09b42213 | 4197 | |
cb768824 | 4198 | tree_code tcode = TREE_CODE (t); |
4199 | switch (tcode) | |
09b42213 | 4200 | { |
9c96033c | 4201 | case RESULT_DECL: |
1227ba74 | 4202 | if (lval) |
9c96033c | 4203 | return t; |
4204 | /* We ask for an rvalue for the RESULT_DECL when indirecting | |
92a9c89e | 4205 | through an invisible reference, or in named return value |
4206 | optimization. */ | |
8ea8d065 | 4207 | if (tree *p = ctx->values->get (t)) |
4208 | return *p; | |
4209 | else | |
4210 | { | |
4211 | if (!ctx->quiet) | |
4212 | error ("%qE is not a constant expression", t); | |
4213 | *non_constant_p = true; | |
4214 | } | |
4215 | break; | |
9c96033c | 4216 | |
09b42213 | 4217 | case VAR_DECL: |
9c8aeb66 | 4218 | if (DECL_HAS_VALUE_EXPR_P (t)) |
33603066 | 4219 | return cxx_eval_constant_expression (ctx, DECL_VALUE_EXPR (t), |
4220 | lval, non_constant_p, overflow_p); | |
e3533433 | 4221 | /* fall through */ |
8b2b2f24 | 4222 | case CONST_DECL: |
4223 | /* We used to not check lval for CONST_DECL, but darwin.c uses | |
4224 | CONST_DECL for aggregate constants. */ | |
1227ba74 | 4225 | if (lval) |
09b42213 | 4226 | return t; |
bb6e576c | 4227 | /* is_really_empty_class doesn't take into account _vptr, so initializing |
4228 | otherwise empty class with { } would overwrite the initializer that | |
4229 | initialize_vtable created for us. */ | |
594cc00c | 4230 | if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
bb6e576c | 4231 | && !TYPE_POLYMORPHIC_P (TREE_TYPE (t)) |
594cc00c | 4232 | && is_really_empty_class (TREE_TYPE (t))) |
c7282bf2 | 4233 | { |
4234 | /* If the class is empty, we aren't actually loading anything. */ | |
4235 | r = build_constructor (TREE_TYPE (t), NULL); | |
4236 | TREE_CONSTANT (r) = true; | |
4237 | } | |
4238 | else if (ctx->strict) | |
2055d27a | 4239 | r = decl_really_constant_value (t); |
4240 | else | |
4241 | r = decl_constant_value (t); | |
09b42213 | 4242 | if (TREE_CODE (r) == TARGET_EXPR |
4243 | && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR) | |
4244 | r = TARGET_EXPR_INITIAL (r); | |
f4ae4202 | 4245 | if (VAR_P (r)) |
cf72f34d | 4246 | if (tree *p = ctx->values->get (r)) |
a143e277 | 4247 | if (*p != NULL_TREE) |
4248 | r = *p; | |
09b42213 | 4249 | if (DECL_P (r)) |
4250 | { | |
f83e6885 | 4251 | if (!ctx->quiet) |
09b42213 | 4252 | non_const_var_error (r); |
4253 | *non_constant_p = true; | |
4254 | } | |
4255 | break; | |
4256 | ||
90567983 | 4257 | case DEBUG_BEGIN_STMT: |
4258 | /* ??? It might be nice to retain this information somehow, so | |
4259 | as to be able to step into a constexpr function call. */ | |
4260 | /* Fall through. */ | |
4261 | ||
09b42213 | 4262 | case FUNCTION_DECL: |
4263 | case TEMPLATE_DECL: | |
4264 | case LABEL_DECL: | |
00f21715 | 4265 | case LABEL_EXPR: |
4266 | case CASE_LABEL_EXPR: | |
2a2770c6 | 4267 | case PREDICT_EXPR: |
09b42213 | 4268 | return t; |
4269 | ||
4270 | case PARM_DECL: | |
90ad495b | 4271 | if (lval && !TYPE_REF_P (TREE_TYPE (t))) |
9c96033c | 4272 | /* glvalue use. */; |
4273 | else if (tree *p = ctx->values->get (r)) | |
4274 | r = *p; | |
1227ba74 | 4275 | else if (lval) |
09b42213 | 4276 | /* Defer in case this is only used for its type. */; |
90ad495b | 4277 | else if (TYPE_REF_P (TREE_TYPE (t))) |
1eb418cc | 4278 | /* Defer, there's no lvalue->rvalue conversion. */; |
53d2f3de | 4279 | else if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
4280 | && is_really_empty_class (TREE_TYPE (t))) | |
a6613de7 | 4281 | { |
4282 | /* If the class is empty, we aren't actually loading anything. */ | |
4283 | r = build_constructor (TREE_TYPE (t), NULL); | |
4284 | TREE_CONSTANT (r) = true; | |
4285 | } | |
09b42213 | 4286 | else |
4287 | { | |
f83e6885 | 4288 | if (!ctx->quiet) |
09b42213 | 4289 | error ("%qE is not a constant expression", t); |
4290 | *non_constant_p = true; | |
4291 | } | |
4292 | break; | |
4293 | ||
4294 | case CALL_EXPR: | |
4295 | case AGGR_INIT_EXPR: | |
1227ba74 | 4296 | r = cxx_eval_call_expression (ctx, t, lval, |
09b42213 | 4297 | non_constant_p, overflow_p); |
4298 | break; | |
4299 | ||
9c96033c | 4300 | case DECL_EXPR: |
4301 | { | |
4302 | r = DECL_EXPR_DECL (t); | |
4303 | if (AGGREGATE_TYPE_P (TREE_TYPE (r)) | |
4304 | || VECTOR_TYPE_P (TREE_TYPE (r))) | |
4305 | { | |
4306 | new_ctx = *ctx; | |
4307 | new_ctx.object = r; | |
4308 | new_ctx.ctor = build_constructor (TREE_TYPE (r), NULL); | |
165d0d5b | 4309 | CONSTRUCTOR_NO_CLEARING (new_ctx.ctor) = true; |
9c96033c | 4310 | new_ctx.values->put (r, new_ctx.ctor); |
4311 | ctx = &new_ctx; | |
4312 | } | |
4313 | ||
4314 | if (tree init = DECL_INITIAL (r)) | |
4315 | { | |
4316 | init = cxx_eval_constant_expression (ctx, init, | |
f83e6885 | 4317 | false, |
b2a43197 | 4318 | non_constant_p, overflow_p); |
5898f0d7 | 4319 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 4320 | init = unshare_constructor (init); |
9c96033c | 4321 | ctx->values->put (r, init); |
4322 | } | |
4323 | else if (ctx == &new_ctx) | |
4324 | /* We gave it a CONSTRUCTOR above. */; | |
4325 | else | |
4326 | ctx->values->put (r, NULL_TREE); | |
4327 | } | |
4328 | break; | |
4329 | ||
09b42213 | 4330 | case TARGET_EXPR: |
4331 | if (!literal_type_p (TREE_TYPE (t))) | |
4332 | { | |
f83e6885 | 4333 | if (!ctx->quiet) |
09b42213 | 4334 | { |
bc35ef65 | 4335 | auto_diagnostic_group d; |
09b42213 | 4336 | error ("temporary of non-literal type %qT in a " |
4337 | "constant expression", TREE_TYPE (t)); | |
4338 | explain_non_literal_class (TREE_TYPE (t)); | |
4339 | } | |
4340 | *non_constant_p = true; | |
4341 | break; | |
4342 | } | |
cf72f34d | 4343 | if ((AGGREGATE_TYPE_P (TREE_TYPE (t)) || VECTOR_TYPE_P (TREE_TYPE (t)))) |
4344 | { | |
4345 | /* We're being expanded without an explicit target, so start | |
4346 | initializing a new object; expansion with an explicit target | |
4347 | strips the TARGET_EXPR before we get here. */ | |
4348 | new_ctx = *ctx; | |
4349 | new_ctx.ctor = build_constructor (TREE_TYPE (t), NULL); | |
165d0d5b | 4350 | CONSTRUCTOR_NO_CLEARING (new_ctx.ctor) = true; |
cf72f34d | 4351 | new_ctx.object = TARGET_EXPR_SLOT (t); |
4352 | ctx->values->put (new_ctx.object, new_ctx.ctor); | |
4353 | ctx = &new_ctx; | |
4354 | } | |
1227ba74 | 4355 | /* Pass false for 'lval' because this indicates |
09b42213 | 4356 | initialization of a temporary. */ |
cf72f34d | 4357 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 4358 | false, |
b2a43197 | 4359 | non_constant_p, overflow_p); |
09b42213 | 4360 | if (!*non_constant_p) |
4361 | /* Adjust the type of the result to the type of the temporary. */ | |
4362 | r = adjust_temp_type (TREE_TYPE (t), r); | |
1227ba74 | 4363 | if (lval) |
1eb418cc | 4364 | { |
4365 | tree slot = TARGET_EXPR_SLOT (t); | |
e283bb4f | 4366 | r = unshare_constructor (r); |
1eb418cc | 4367 | ctx->values->put (slot, r); |
4368 | return slot; | |
4369 | } | |
09b42213 | 4370 | break; |
4371 | ||
9c96033c | 4372 | case INIT_EXPR: |
9c96033c | 4373 | case MODIFY_EXPR: |
2a2770c6 | 4374 | gcc_assert (jump_target == NULL || *jump_target == NULL_TREE); |
1227ba74 | 4375 | r = cxx_eval_store_expression (ctx, t, lval, |
9c96033c | 4376 | non_constant_p, overflow_p); |
4377 | break; | |
4378 | ||
09b42213 | 4379 | case SCOPE_REF: |
cf72f34d | 4380 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 4381 | lval, |
b2a43197 | 4382 | non_constant_p, overflow_p); |
09b42213 | 4383 | break; |
4384 | ||
4385 | case RETURN_EXPR: | |
10fb495c | 4386 | if (TREE_OPERAND (t, 0) != NULL_TREE) |
4387 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
4388 | lval, | |
4389 | non_constant_p, overflow_p); | |
2c572f5f | 4390 | if (jump_target) |
4391 | *jump_target = t; | |
4392 | else | |
4393 | { | |
4394 | /* Can happen with ({ return true; }) && false; passed to | |
4395 | maybe_constant_value. There is nothing to jump over in this | |
4396 | case, and the bug will be diagnosed later. */ | |
4397 | gcc_assert (ctx->quiet); | |
4398 | *non_constant_p = true; | |
4399 | } | |
00f21715 | 4400 | break; |
4401 | ||
e0e672a0 | 4402 | case SAVE_EXPR: |
4403 | /* Avoid evaluating a SAVE_EXPR more than once. */ | |
4404 | if (tree *p = ctx->values->get (t)) | |
4405 | r = *p; | |
4406 | else | |
4407 | { | |
c8f6aeb1 | 4408 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), false, |
e0e672a0 | 4409 | non_constant_p, overflow_p); |
4410 | ctx->values->put (t, r); | |
2631cb67 | 4411 | if (ctx->save_exprs) |
4412 | ctx->save_exprs->add (t); | |
e0e672a0 | 4413 | } |
4414 | break; | |
4415 | ||
09b42213 | 4416 | case NON_LVALUE_EXPR: |
4417 | case TRY_CATCH_EXPR: | |
7f67d68c | 4418 | case TRY_BLOCK: |
09b42213 | 4419 | case CLEANUP_POINT_EXPR: |
4420 | case MUST_NOT_THROW_EXPR: | |
9c96033c | 4421 | case EXPR_STMT: |
4422 | case EH_SPEC_BLOCK: | |
cf72f34d | 4423 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 4424 | lval, |
00f21715 | 4425 | non_constant_p, overflow_p, |
4426 | jump_target); | |
09b42213 | 4427 | break; |
4428 | ||
7f67d68c | 4429 | case TRY_FINALLY_EXPR: |
4430 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4431 | non_constant_p, overflow_p, | |
4432 | jump_target); | |
4433 | if (!*non_constant_p) | |
4434 | /* Also evaluate the cleanup. */ | |
4435 | cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), true, | |
4436 | non_constant_p, overflow_p, | |
4437 | jump_target); | |
4438 | break; | |
4439 | ||
09b42213 | 4440 | /* These differ from cxx_eval_unary_expression in that this doesn't |
4441 | check for a constant operand or result; an address can be | |
4442 | constant without its operand being, and vice versa. */ | |
d2c63826 | 4443 | case MEM_REF: |
09b42213 | 4444 | case INDIRECT_REF: |
1227ba74 | 4445 | r = cxx_eval_indirect_ref (ctx, t, lval, |
09b42213 | 4446 | non_constant_p, overflow_p); |
4447 | break; | |
4448 | ||
4449 | case ADDR_EXPR: | |
4450 | { | |
4451 | tree oldop = TREE_OPERAND (t, 0); | |
cf72f34d | 4452 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4453 | /*lval*/true, |
b2a43197 | 4454 | non_constant_p, overflow_p); |
09b42213 | 4455 | /* Don't VERIFY_CONSTANT here. */ |
4456 | if (*non_constant_p) | |
4457 | return t; | |
1eb418cc | 4458 | gcc_checking_assert (TREE_CODE (op) != CONSTRUCTOR); |
09b42213 | 4459 | /* This function does more aggressive folding than fold itself. */ |
4460 | r = build_fold_addr_expr_with_type (op, TREE_TYPE (t)); | |
4461 | if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop) | |
4462 | return t; | |
4463 | break; | |
4464 | } | |
4465 | ||
4466 | case REALPART_EXPR: | |
4467 | case IMAGPART_EXPR: | |
6fe424c2 | 4468 | if (lval) |
4469 | { | |
4470 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4471 | non_constant_p, overflow_p); | |
4472 | if (r == error_mark_node) | |
4473 | ; | |
4474 | else if (r == TREE_OPERAND (t, 0)) | |
4475 | r = t; | |
4476 | else | |
4477 | r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), r); | |
4478 | break; | |
4479 | } | |
4480 | /* FALLTHRU */ | |
09b42213 | 4481 | case CONJ_EXPR: |
4482 | case FIX_TRUNC_EXPR: | |
4483 | case FLOAT_EXPR: | |
4484 | case NEGATE_EXPR: | |
4485 | case ABS_EXPR: | |
19b4138e | 4486 | case ABSU_EXPR: |
09b42213 | 4487 | case BIT_NOT_EXPR: |
4488 | case TRUTH_NOT_EXPR: | |
4489 | case FIXED_CONVERT_EXPR: | |
1227ba74 | 4490 | r = cxx_eval_unary_expression (ctx, t, lval, |
09b42213 | 4491 | non_constant_p, overflow_p); |
4492 | break; | |
4493 | ||
4494 | case SIZEOF_EXPR: | |
d2c63826 | 4495 | r = fold_sizeof_expr (t); |
09b42213 | 4496 | VERIFY_CONSTANT (r); |
4497 | break; | |
4498 | ||
4499 | case COMPOUND_EXPR: | |
4500 | { | |
4501 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
4502 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
4503 | introduced by build_call_a. */ | |
4504 | tree op0 = TREE_OPERAND (t, 0); | |
4505 | tree op1 = TREE_OPERAND (t, 1); | |
4506 | STRIP_NOPS (op1); | |
4507 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
4508 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
f83e6885 | 4509 | r = cxx_eval_constant_expression (ctx, op0, |
1227ba74 | 4510 | lval, non_constant_p, overflow_p, |
00f21715 | 4511 | jump_target); |
09b42213 | 4512 | else |
4513 | { | |
4514 | /* Check that the LHS is constant and then discard it. */ | |
f83e6885 | 4515 | cxx_eval_constant_expression (ctx, op0, |
c8f6aeb1 | 4516 | true, non_constant_p, overflow_p, |
00f21715 | 4517 | jump_target); |
cf03ba19 | 4518 | if (*non_constant_p) |
4519 | return t; | |
09b42213 | 4520 | op1 = TREE_OPERAND (t, 1); |
f83e6885 | 4521 | r = cxx_eval_constant_expression (ctx, op1, |
1227ba74 | 4522 | lval, non_constant_p, overflow_p, |
00f21715 | 4523 | jump_target); |
09b42213 | 4524 | } |
4525 | } | |
4526 | break; | |
4527 | ||
4528 | case POINTER_PLUS_EXPR: | |
57e83b58 | 4529 | case POINTER_DIFF_EXPR: |
09b42213 | 4530 | case PLUS_EXPR: |
4531 | case MINUS_EXPR: | |
4532 | case MULT_EXPR: | |
4533 | case TRUNC_DIV_EXPR: | |
4534 | case CEIL_DIV_EXPR: | |
4535 | case FLOOR_DIV_EXPR: | |
4536 | case ROUND_DIV_EXPR: | |
4537 | case TRUNC_MOD_EXPR: | |
4538 | case CEIL_MOD_EXPR: | |
4539 | case ROUND_MOD_EXPR: | |
4540 | case RDIV_EXPR: | |
4541 | case EXACT_DIV_EXPR: | |
4542 | case MIN_EXPR: | |
4543 | case MAX_EXPR: | |
4544 | case LSHIFT_EXPR: | |
4545 | case RSHIFT_EXPR: | |
4546 | case LROTATE_EXPR: | |
4547 | case RROTATE_EXPR: | |
4548 | case BIT_IOR_EXPR: | |
4549 | case BIT_XOR_EXPR: | |
4550 | case BIT_AND_EXPR: | |
4551 | case TRUTH_XOR_EXPR: | |
4552 | case LT_EXPR: | |
4553 | case LE_EXPR: | |
4554 | case GT_EXPR: | |
4555 | case GE_EXPR: | |
4556 | case EQ_EXPR: | |
4557 | case NE_EXPR: | |
4558 | case UNORDERED_EXPR: | |
4559 | case ORDERED_EXPR: | |
4560 | case UNLT_EXPR: | |
4561 | case UNLE_EXPR: | |
4562 | case UNGT_EXPR: | |
4563 | case UNGE_EXPR: | |
4564 | case UNEQ_EXPR: | |
4565 | case LTGT_EXPR: | |
4566 | case RANGE_EXPR: | |
4567 | case COMPLEX_EXPR: | |
1227ba74 | 4568 | r = cxx_eval_binary_expression (ctx, t, lval, |
09b42213 | 4569 | non_constant_p, overflow_p); |
4570 | break; | |
4571 | ||
4572 | /* fold can introduce non-IF versions of these; still treat them as | |
4573 | short-circuiting. */ | |
4574 | case TRUTH_AND_EXPR: | |
4575 | case TRUTH_ANDIF_EXPR: | |
cf72f34d | 4576 | r = cxx_eval_logical_expression (ctx, t, boolean_false_node, |
09b42213 | 4577 | boolean_true_node, |
1227ba74 | 4578 | lval, |
09b42213 | 4579 | non_constant_p, overflow_p); |
4580 | break; | |
4581 | ||
4582 | case TRUTH_OR_EXPR: | |
4583 | case TRUTH_ORIF_EXPR: | |
cf72f34d | 4584 | r = cxx_eval_logical_expression (ctx, t, boolean_true_node, |
09b42213 | 4585 | boolean_false_node, |
1227ba74 | 4586 | lval, |
09b42213 | 4587 | non_constant_p, overflow_p); |
4588 | break; | |
4589 | ||
4590 | case ARRAY_REF: | |
1227ba74 | 4591 | r = cxx_eval_array_reference (ctx, t, lval, |
09b42213 | 4592 | non_constant_p, overflow_p); |
4593 | break; | |
4594 | ||
4595 | case COMPONENT_REF: | |
4596 | if (is_overloaded_fn (t)) | |
4597 | { | |
4598 | /* We can only get here in checking mode via | |
4599 | build_non_dependent_expr, because any expression that | |
4600 | calls or takes the address of the function will have | |
4601 | pulled a FUNCTION_DECL out of the COMPONENT_REF. */ | |
f83e6885 | 4602 | gcc_checking_assert (ctx->quiet || errorcount); |
09b42213 | 4603 | *non_constant_p = true; |
4604 | return t; | |
4605 | } | |
1227ba74 | 4606 | r = cxx_eval_component_reference (ctx, t, lval, |
09b42213 | 4607 | non_constant_p, overflow_p); |
4608 | break; | |
4609 | ||
4610 | case BIT_FIELD_REF: | |
1227ba74 | 4611 | r = cxx_eval_bit_field_ref (ctx, t, lval, |
09b42213 | 4612 | non_constant_p, overflow_p); |
4613 | break; | |
4614 | ||
4615 | case COND_EXPR: | |
2a2770c6 | 4616 | if (jump_target && *jump_target) |
4617 | { | |
4618 | /* When jumping to a label, the label might be either in the | |
4619 | then or else blocks, so process then block first in skipping | |
4620 | mode first, and if we are still in the skipping mode at its end, | |
4621 | process the else block too. */ | |
4622 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
4623 | lval, non_constant_p, overflow_p, | |
4624 | jump_target); | |
4625 | if (*jump_target) | |
4626 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
4627 | lval, non_constant_p, overflow_p, | |
4628 | jump_target); | |
4629 | break; | |
4630 | } | |
1227ba74 | 4631 | r = cxx_eval_conditional_expression (ctx, t, lval, |
00f21715 | 4632 | non_constant_p, overflow_p, |
4633 | jump_target); | |
09b42213 | 4634 | break; |
31595caf | 4635 | case VEC_COND_EXPR: |
4636 | r = cxx_eval_vector_conditional_expression (ctx, t, non_constant_p, | |
4637 | overflow_p); | |
4638 | break; | |
09b42213 | 4639 | |
4640 | case CONSTRUCTOR: | |
1a3631bc | 4641 | if (TREE_CONSTANT (t)) |
58b0f9ce | 4642 | { |
4643 | /* Don't re-process a constant CONSTRUCTOR, but do fold it to | |
4644 | VECTOR_CST if applicable. */ | |
79e65a6b | 4645 | verify_constructor_flags (t); |
58b0f9ce | 4646 | if (TREE_CONSTANT (t)) |
4647 | return fold (t); | |
4648 | } | |
1227ba74 | 4649 | r = cxx_eval_bare_aggregate (ctx, t, lval, |
09b42213 | 4650 | non_constant_p, overflow_p); |
4651 | break; | |
4652 | ||
4653 | case VEC_INIT_EXPR: | |
4654 | /* We can get this in a defaulted constructor for a class with a | |
4655 | non-static data member of array type. Either the initializer will | |
4656 | be NULL, meaning default-initialization, or it will be an lvalue | |
4657 | or xvalue of the same type, meaning direct-initialization from the | |
4658 | corresponding member. */ | |
1227ba74 | 4659 | r = cxx_eval_vec_init (ctx, t, lval, |
09b42213 | 4660 | non_constant_p, overflow_p); |
4661 | break; | |
4662 | ||
09b42213 | 4663 | case VEC_PERM_EXPR: |
1227ba74 | 4664 | r = cxx_eval_trinary_expression (ctx, t, lval, |
09b42213 | 4665 | non_constant_p, overflow_p); |
4666 | break; | |
4667 | ||
941fafa5 | 4668 | case NOP_EXPR: |
4669 | if (REINTERPRET_CAST_P (t)) | |
4670 | { | |
4671 | if (!ctx->quiet) | |
d3a3cfb8 | 4672 | error_at (cp_expr_loc_or_loc (t, input_location), |
941fafa5 | 4673 | "a reinterpret_cast is not a constant expression"); |
4674 | *non_constant_p = true; | |
4675 | return t; | |
4676 | } | |
4677 | /* FALLTHROUGH. */ | |
09b42213 | 4678 | case CONVERT_EXPR: |
4679 | case VIEW_CONVERT_EXPR: | |
d2c63826 | 4680 | case UNARY_PLUS_EXPR: |
09b42213 | 4681 | { |
4682 | tree oldop = TREE_OPERAND (t, 0); | |
d2c63826 | 4683 | |
cf72f34d | 4684 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4685 | lval, |
b2a43197 | 4686 | non_constant_p, overflow_p); |
09b42213 | 4687 | if (*non_constant_p) |
4688 | return t; | |
f16ed232 | 4689 | tree type = TREE_TYPE (t); |
4690 | if (TREE_CODE (op) == PTRMEM_CST | |
4691 | && !TYPE_PTRMEM_P (type)) | |
4692 | op = cplus_expand_constant (op); | |
941fafa5 | 4693 | |
6a9b35ef | 4694 | if (TREE_CODE (op) == PTRMEM_CST && tcode == NOP_EXPR) |
4695 | { | |
941fafa5 | 4696 | if (!same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (op)) |
4697 | && !can_convert_qual (type, op)) | |
4698 | op = cplus_expand_constant (op); | |
4699 | return cp_fold_convert (type, op); | |
6a9b35ef | 4700 | } |
cb768824 | 4701 | |
d03fa520 | 4702 | if (INDIRECT_TYPE_P (type) && TREE_CODE (op) == INTEGER_CST) |
09b42213 | 4703 | { |
cb768824 | 4704 | if (integer_zerop (op)) |
4705 | { | |
90ad495b | 4706 | if (TYPE_REF_P (type)) |
cb768824 | 4707 | { |
4708 | if (!ctx->quiet) | |
d3a3cfb8 | 4709 | error_at (cp_expr_loc_or_loc (t, input_location), |
cb768824 | 4710 | "dereferencing a null pointer"); |
4711 | *non_constant_p = true; | |
4712 | return t; | |
4713 | } | |
90ad495b | 4714 | else if (TYPE_PTR_P (TREE_TYPE (op))) |
cb768824 | 4715 | { |
4716 | tree from = TREE_TYPE (op); | |
4717 | ||
4718 | if (!can_convert (type, from, tf_none)) | |
4719 | { | |
4720 | if (!ctx->quiet) | |
d3a3cfb8 | 4721 | error_at (cp_expr_loc_or_loc (t, input_location), |
cb768824 | 4722 | "conversion of %qT null pointer to %qT " |
4723 | "is not a constant expression", | |
4724 | from, type); | |
4725 | *non_constant_p = true; | |
4726 | return t; | |
4727 | } | |
4728 | } | |
4729 | } | |
4730 | else | |
4731 | { | |
4732 | /* This detects for example: | |
4733 | reinterpret_cast<void*>(sizeof 0) | |
4734 | */ | |
4735 | if (!ctx->quiet) | |
d3a3cfb8 | 4736 | error_at (cp_expr_loc_or_loc (t, input_location), |
cb768824 | 4737 | "%<reinterpret_cast<%T>(%E)%> is not " |
ea034e2c | 4738 | "a constant expression", |
cb768824 | 4739 | type, op); |
4740 | *non_constant_p = true; | |
4741 | return t; | |
4742 | } | |
09b42213 | 4743 | } |
941fafa5 | 4744 | |
d2c63826 | 4745 | if (op == oldop && tcode != UNARY_PLUS_EXPR) |
09b42213 | 4746 | /* We didn't fold at the top so we could check for ptr-int |
4747 | conversion. */ | |
4748 | return fold (t); | |
941fafa5 | 4749 | |
6b53d686 | 4750 | /* Handle an array's bounds having been deduced after we built |
4751 | the wrapping expression. */ | |
4752 | if (same_type_ignoring_tlq_and_bounds_p (type, TREE_TYPE (op))) | |
4753 | r = op; | |
4754 | else if (tcode == UNARY_PLUS_EXPR) | |
d2c63826 | 4755 | r = fold_convert (TREE_TYPE (t), op); |
4756 | else | |
4757 | r = fold_build1 (tcode, type, op); | |
941fafa5 | 4758 | |
09b42213 | 4759 | /* Conversion of an out-of-range value has implementation-defined |
4760 | behavior; the language considers it different from arithmetic | |
4761 | overflow, which is undefined. */ | |
4762 | if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op)) | |
4763 | TREE_OVERFLOW (r) = false; | |
4764 | } | |
4765 | break; | |
4766 | ||
4767 | case EMPTY_CLASS_EXPR: | |
4768 | /* This is good enough for a function argument that might not get | |
4769 | used, and they can't do anything with it, so just return it. */ | |
4770 | return t; | |
4771 | ||
9c96033c | 4772 | case STATEMENT_LIST: |
00f21715 | 4773 | new_ctx = *ctx; |
4774 | new_ctx.ctor = new_ctx.object = NULL_TREE; | |
f83e6885 | 4775 | return cxx_eval_statement_list (&new_ctx, t, |
00f21715 | 4776 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4777 | |
4778 | case BIND_EXPR: | |
4779 | return cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t), | |
1227ba74 | 4780 | lval, |
00f21715 | 4781 | non_constant_p, overflow_p, |
4782 | jump_target); | |
9c96033c | 4783 | |
09b42213 | 4784 | case PREINCREMENT_EXPR: |
4785 | case POSTINCREMENT_EXPR: | |
4786 | case PREDECREMENT_EXPR: | |
4787 | case POSTDECREMENT_EXPR: | |
f83e6885 | 4788 | return cxx_eval_increment_expression (ctx, t, |
1227ba74 | 4789 | lval, non_constant_p, overflow_p); |
9c96033c | 4790 | |
4791 | case LAMBDA_EXPR: | |
09b42213 | 4792 | case NEW_EXPR: |
4793 | case VEC_NEW_EXPR: | |
4794 | case DELETE_EXPR: | |
4795 | case VEC_DELETE_EXPR: | |
4796 | case THROW_EXPR: | |
09b42213 | 4797 | case MODOP_EXPR: |
4798 | /* GCC internal stuff. */ | |
4799 | case VA_ARG_EXPR: | |
09b42213 | 4800 | case NON_DEPENDENT_EXPR: |
4801 | case BASELINK: | |
09b42213 | 4802 | case OFFSET_REF: |
f83e6885 | 4803 | if (!ctx->quiet) |
d3a3cfb8 | 4804 | error_at (cp_expr_loc_or_loc (t, input_location), |
ea034e2c | 4805 | "expression %qE is not a constant expression", t); |
09b42213 | 4806 | *non_constant_p = true; |
4807 | break; | |
4808 | ||
bb6e576c | 4809 | case OBJ_TYPE_REF: |
4810 | { | |
4811 | /* Virtual function call. Let the constexpr machinery figure out | |
4812 | the dynamic type. */ | |
4813 | int token = tree_to_shwi (OBJ_TYPE_REF_TOKEN (t)); | |
4814 | tree obj = OBJ_TYPE_REF_OBJECT (t); | |
4815 | obj = cxx_eval_constant_expression (ctx, obj, lval, non_constant_p, | |
4816 | overflow_p); | |
4817 | /* We expect something in the form of &x.D.2103.D.2094; get x. */ | |
85c4b1bb | 4818 | if (TREE_CODE (obj) != ADDR_EXPR |
4819 | || !DECL_P (get_base_address (TREE_OPERAND (obj, 0)))) | |
bb6e576c | 4820 | { |
4821 | if (!ctx->quiet) | |
4822 | error_at (cp_expr_loc_or_loc (t, input_location), | |
4823 | "expression %qE is not a constant expression", t); | |
4824 | *non_constant_p = true; | |
4825 | return t; | |
4826 | } | |
4827 | obj = TREE_OPERAND (obj, 0); | |
e3cb8102 | 4828 | while (TREE_CODE (obj) == COMPONENT_REF |
4829 | && DECL_FIELD_IS_BASE (TREE_OPERAND (obj, 1))) | |
bb6e576c | 4830 | obj = TREE_OPERAND (obj, 0); |
4831 | tree objtype = TREE_TYPE (obj); | |
4832 | /* Find the function decl in the virtual functions list. TOKEN is | |
4833 | the DECL_VINDEX that says which function we're looking for. */ | |
4834 | tree virtuals = BINFO_VIRTUALS (TYPE_BINFO (objtype)); | |
4835 | r = TREE_VALUE (chain_index (token, virtuals)); | |
4836 | break; | |
4837 | } | |
4838 | ||
cf72f34d | 4839 | case PLACEHOLDER_EXPR: |
85de9604 | 4840 | /* Use of the value or address of the current object. */ |
4841 | if (tree ctor = lookup_placeholder (ctx, lval, TREE_TYPE (t))) | |
4842 | return cxx_eval_constant_expression (ctx, ctor, lval, | |
4843 | non_constant_p, overflow_p); | |
4844 | /* A placeholder without a referent. We can get here when | |
4845 | checking whether NSDMIs are noexcept, or in massage_init_elt; | |
4846 | just say it's non-constant for now. */ | |
4847 | gcc_assert (ctx->quiet); | |
4848 | *non_constant_p = true; | |
cf72f34d | 4849 | break; |
4850 | ||
cf03ba19 | 4851 | case EXIT_EXPR: |
4852 | { | |
4853 | tree cond = TREE_OPERAND (t, 0); | |
4854 | cond = cxx_eval_constant_expression (ctx, cond, /*lval*/false, | |
4855 | non_constant_p, overflow_p); | |
4856 | VERIFY_CONSTANT (cond); | |
4857 | if (integer_nonzerop (cond)) | |
4858 | *jump_target = t; | |
4859 | } | |
4860 | break; | |
4861 | ||
9c96033c | 4862 | case GOTO_EXPR: |
00f21715 | 4863 | *jump_target = TREE_OPERAND (t, 0); |
d29e4e8c | 4864 | gcc_assert (breaks (jump_target) || continues (jump_target) |
4865 | /* Allow for jumping to a cdtor_label. */ | |
4866 | || returns (jump_target)); | |
00f21715 | 4867 | break; |
4868 | ||
9c96033c | 4869 | case LOOP_EXPR: |
f83e6885 | 4870 | cxx_eval_loop_expr (ctx, t, |
00f21715 | 4871 | non_constant_p, overflow_p, jump_target); |
4872 | break; | |
4873 | ||
9c96033c | 4874 | case SWITCH_EXPR: |
f83e6885 | 4875 | cxx_eval_switch_expr (ctx, t, |
00f21715 | 4876 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4877 | break; |
4878 | ||
56c12fd4 | 4879 | case REQUIRES_EXPR: |
4880 | /* It's possible to get a requires-expression in a constant | |
4881 | expression. For example: | |
4882 | ||
4883 | template<typename T> concept bool C() { | |
4884 | return requires (T t) { t; }; | |
4885 | } | |
4886 | ||
4887 | template<typename T> requires !C<T>() void f(T); | |
4888 | ||
4889 | Normalization leaves f with the associated constraint | |
4890 | '!requires (T t) { ... }' which is not transformed into | |
4891 | a constraint. */ | |
4892 | if (!processing_template_decl) | |
4893 | return evaluate_constraint_expression (t, NULL_TREE); | |
4894 | else | |
4895 | *non_constant_p = true; | |
4896 | return t; | |
4897 | ||
24c6ee98 | 4898 | case ANNOTATE_EXPR: |
24c6ee98 | 4899 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
4900 | lval, | |
4901 | non_constant_p, overflow_p, | |
4902 | jump_target); | |
4903 | break; | |
4904 | ||
7285637a | 4905 | case USING_STMT: |
4906 | r = void_node; | |
4907 | break; | |
4908 | ||
09b42213 | 4909 | default: |
b9a3af23 | 4910 | if (STATEMENT_CODE_P (TREE_CODE (t))) |
4911 | { | |
4912 | /* This function doesn't know how to deal with pre-genericize | |
4913 | statements; this can only happen with statement-expressions, | |
4914 | so for now just fail. */ | |
4915 | if (!ctx->quiet) | |
4916 | error_at (EXPR_LOCATION (t), | |
ea034e2c | 4917 | "statement is not a constant expression"); |
b9a3af23 | 4918 | } |
4919 | else | |
4920 | internal_error ("unexpected expression %qE of kind %s", t, | |
4921 | get_tree_code_name (TREE_CODE (t))); | |
09b42213 | 4922 | *non_constant_p = true; |
4923 | break; | |
4924 | } | |
4925 | ||
4926 | if (r == error_mark_node) | |
4927 | *non_constant_p = true; | |
4928 | ||
4929 | if (*non_constant_p) | |
4930 | return t; | |
4931 | else | |
4932 | return r; | |
4933 | } | |
4934 | ||
6e1bbaae | 4935 | /* P0859: A function is needed for constant evaluation if it is a constexpr |
4936 | function that is named by an expression ([basic.def.odr]) that is | |
4937 | potentially constant evaluated. | |
4938 | ||
4939 | So we need to instantiate any constexpr functions mentioned by the | |
4940 | expression even if the definition isn't needed for evaluating the | |
4941 | expression. */ | |
4942 | ||
4943 | static tree | |
4944 | instantiate_cx_fn_r (tree *tp, int *walk_subtrees, void */*data*/) | |
4945 | { | |
4946 | if (TREE_CODE (*tp) == FUNCTION_DECL | |
4947 | && DECL_DECLARED_CONSTEXPR_P (*tp) | |
4948 | && !DECL_INITIAL (*tp) | |
eed138cf | 4949 | && !trivial_fn_p (*tp) |
6e1bbaae | 4950 | && DECL_TEMPLOID_INSTANTIATION (*tp)) |
4951 | { | |
4952 | ++function_depth; | |
4953 | instantiate_decl (*tp, /*defer_ok*/false, /*expl_inst*/false); | |
4954 | --function_depth; | |
4955 | } | |
4956 | else if (TREE_CODE (*tp) == CALL_EXPR | |
4957 | || TREE_CODE (*tp) == AGGR_INIT_EXPR) | |
4958 | { | |
4959 | if (EXPR_HAS_LOCATION (*tp)) | |
4960 | input_location = EXPR_LOCATION (*tp); | |
4961 | } | |
4962 | ||
4963 | if (!EXPR_P (*tp)) | |
4964 | *walk_subtrees = 0; | |
4965 | ||
4966 | return NULL_TREE; | |
4967 | } | |
4968 | static void | |
4969 | instantiate_constexpr_fns (tree t) | |
4970 | { | |
4971 | location_t loc = input_location; | |
4972 | cp_walk_tree_without_duplicates (&t, instantiate_cx_fn_r, NULL); | |
4973 | input_location = loc; | |
4974 | } | |
4975 | ||
18d371d3 | 4976 | /* ALLOW_NON_CONSTANT is false if T is required to be a constant expression. |
3f892eaf | 4977 | STRICT has the same sense as for constant_value_1: true if we only allow |
4978 | conforming C++ constant expressions, or false if we want a constant value | |
4979 | even if it doesn't conform. | |
18d371d3 | 4980 | PRETEND_CONST_REQUIRED is true if T is required to be const-evaluated as |
4981 | per P0595 even when ALLOW_NON_CONSTANT is true. */ | |
4982 | ||
09b42213 | 4983 | static tree |
cf72f34d | 4984 | cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, |
18d371d3 | 4985 | bool strict = true, |
4986 | bool pretend_const_required = false, | |
4987 | tree object = NULL_TREE) | |
09b42213 | 4988 | { |
c300fe28 | 4989 | auto_timevar time (TV_CONSTEXPR); |
4990 | ||
09b42213 | 4991 | bool non_constant_p = false; |
4992 | bool overflow_p = false; | |
cf72f34d | 4993 | hash_map<tree,tree> map; |
2631cb67 | 4994 | |
2a2770c6 | 4995 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, NULL, NULL, |
18d371d3 | 4996 | allow_non_constant, strict, |
4997 | pretend_const_required || !allow_non_constant }; | |
2631cb67 | 4998 | |
cf72f34d | 4999 | tree type = initialized_type (t); |
cf72f34d | 5000 | tree r = t; |
5001 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) | |
5002 | { | |
5003 | /* In C++14 an NSDMI can participate in aggregate initialization, | |
5004 | and can refer to the address of the object being initialized, so | |
5005 | we need to pass in the relevant VAR_DECL if we want to do the | |
5006 | evaluation in a single pass. The evaluation will dynamically | |
5007 | update ctx.values for the VAR_DECL. We use the same strategy | |
5008 | for C++11 constexpr constructors that refer to the object being | |
5009 | initialized. */ | |
5010 | ctx.ctor = build_constructor (type, NULL); | |
165d0d5b | 5011 | CONSTRUCTOR_NO_CLEARING (ctx.ctor) = true; |
9c96033c | 5012 | if (!object) |
5013 | { | |
5014 | if (TREE_CODE (t) == TARGET_EXPR) | |
5015 | object = TARGET_EXPR_SLOT (t); | |
5016 | else if (TREE_CODE (t) == AGGR_INIT_EXPR) | |
5017 | object = AGGR_INIT_EXPR_SLOT (t); | |
5018 | } | |
cf72f34d | 5019 | ctx.object = object; |
5020 | if (object) | |
5021 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
5022 | (type, TREE_TYPE (object))); | |
5023 | if (object && DECL_P (object)) | |
5024 | map.put (object, ctx.ctor); | |
5025 | if (TREE_CODE (r) == TARGET_EXPR) | |
5026 | /* Avoid creating another CONSTRUCTOR when we expand the | |
5027 | TARGET_EXPR. */ | |
5028 | r = TARGET_EXPR_INITIAL (r); | |
5029 | } | |
5030 | ||
6e1bbaae | 5031 | instantiate_constexpr_fns (r); |
f83e6885 | 5032 | r = cxx_eval_constant_expression (&ctx, r, |
b2a43197 | 5033 | false, &non_constant_p, &overflow_p); |
09b42213 | 5034 | |
5035 | verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); | |
5036 | ||
bbcc9042 | 5037 | /* Mutable logic is a bit tricky: we want to allow initialization of |
5038 | constexpr variables with mutable members, but we can't copy those | |
5039 | members to another constexpr variable. */ | |
5040 | if (TREE_CODE (r) == CONSTRUCTOR | |
5041 | && CONSTRUCTOR_MUTABLE_POISON (r)) | |
09b42213 | 5042 | { |
09b42213 | 5043 | if (!allow_non_constant) |
bbcc9042 | 5044 | error ("%qE is not a constant expression because it refers to " |
5045 | "mutable subobjects of %qT", t, type); | |
09b42213 | 5046 | non_constant_p = true; |
5047 | } | |
5048 | ||
c6d97004 | 5049 | if (TREE_CODE (r) == CONSTRUCTOR |
165d0d5b | 5050 | && CONSTRUCTOR_NO_CLEARING (r)) |
c6d97004 | 5051 | { |
5052 | if (!allow_non_constant) | |
5053 | error ("%qE is not a constant expression because it refers to " | |
5054 | "an incompletely initialized variable", t); | |
5055 | TREE_CONSTANT (r) = false; | |
5056 | non_constant_p = true; | |
5057 | } | |
5058 | ||
09b42213 | 5059 | /* Technically we should check this for all subexpressions, but that |
5060 | runs into problems with our internal representation of pointer | |
5061 | subtraction and the 5.19 rules are still in flux. */ | |
5062 | if (CONVERT_EXPR_CODE_P (TREE_CODE (r)) | |
5063 | && ARITHMETIC_TYPE_P (TREE_TYPE (r)) | |
5064 | && TREE_CODE (TREE_OPERAND (r, 0)) == ADDR_EXPR) | |
5065 | { | |
5066 | if (!allow_non_constant) | |
5067 | error ("conversion from pointer type %qT " | |
ea034e2c | 5068 | "to arithmetic type %qT in a constant expression", |
09b42213 | 5069 | TREE_TYPE (TREE_OPERAND (r, 0)), TREE_TYPE (r)); |
5070 | non_constant_p = true; | |
5071 | } | |
5072 | ||
5073 | if (!non_constant_p && overflow_p) | |
5074 | non_constant_p = true; | |
5075 | ||
c6c0523b | 5076 | /* Unshare the result unless it's a CONSTRUCTOR in which case it's already |
5077 | unshared. */ | |
5078 | bool should_unshare = true; | |
5079 | if (r == t || TREE_CODE (r) == CONSTRUCTOR) | |
5080 | should_unshare = false; | |
5081 | ||
09b42213 | 5082 | if (non_constant_p && !allow_non_constant) |
5083 | return error_mark_node; | |
5084 | else if (non_constant_p && TREE_CONSTANT (r)) | |
5085 | { | |
18d371d3 | 5086 | /* If __builtin_is_constant_evaluated () was evaluated to true |
5087 | and the result is not a valid constant expression, we need to | |
5088 | punt. */ | |
5089 | if (pretend_const_required) | |
5090 | return cxx_eval_outermost_constant_expr (t, true, strict, | |
5091 | false, object); | |
1d29f4ea | 5092 | /* This isn't actually constant, so unset TREE_CONSTANT. |
5093 | Don't clear TREE_CONSTANT on ADDR_EXPR, as the middle-end requires | |
5094 | it to be set if it is invariant address, even when it is not | |
5095 | a valid C++ constant expression. Wrap it with a NOP_EXPR | |
5096 | instead. */ | |
5097 | if (EXPR_P (r) && TREE_CODE (r) != ADDR_EXPR) | |
09b42213 | 5098 | r = copy_node (r); |
5099 | else if (TREE_CODE (r) == CONSTRUCTOR) | |
5100 | r = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (r), r); | |
5101 | else | |
5102 | r = build_nop (TREE_TYPE (r), r); | |
5103 | TREE_CONSTANT (r) = false; | |
5104 | } | |
59183fff | 5105 | else if (non_constant_p) |
09b42213 | 5106 | return t; |
5107 | ||
c6c0523b | 5108 | if (should_unshare) |
5109 | r = unshare_expr (r); | |
5110 | ||
09b42213 | 5111 | if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r))) |
5112 | { | |
59183fff | 5113 | r = adjust_temp_type (type, r); |
09b42213 | 5114 | if (TREE_CODE (t) == TARGET_EXPR |
5115 | && TARGET_EXPR_INITIAL (t) == r) | |
5116 | return t; | |
59183fff | 5117 | else if (TREE_CODE (t) != CONSTRUCTOR) |
09b42213 | 5118 | { |
5119 | r = get_target_expr (r); | |
5120 | TREE_CONSTANT (r) = true; | |
09b42213 | 5121 | } |
5122 | } | |
59183fff | 5123 | |
5124 | return r; | |
09b42213 | 5125 | } |
5126 | ||
5127 | /* Returns true if T is a valid subexpression of a constant expression, | |
5128 | even if it isn't itself a constant expression. */ | |
5129 | ||
5130 | bool | |
5131 | is_sub_constant_expr (tree t) | |
5132 | { | |
5133 | bool non_constant_p = false; | |
5134 | bool overflow_p = false; | |
cf72f34d | 5135 | hash_map <tree, tree> map; |
2631cb67 | 5136 | |
18d371d3 | 5137 | constexpr_ctx ctx |
5138 | = { NULL, &map, NULL, NULL, NULL, NULL, true, true, false }; | |
2631cb67 | 5139 | |
6e1bbaae | 5140 | instantiate_constexpr_fns (t); |
f83e6885 | 5141 | cxx_eval_constant_expression (&ctx, t, false, &non_constant_p, |
b2a43197 | 5142 | &overflow_p); |
09b42213 | 5143 | return !non_constant_p && !overflow_p; |
5144 | } | |
5145 | ||
5146 | /* If T represents a constant expression returns its reduced value. | |
5147 | Otherwise return error_mark_node. If T is dependent, then | |
5148 | return NULL. */ | |
5149 | ||
5150 | tree | |
cf72f34d | 5151 | cxx_constant_value (tree t, tree decl) |
09b42213 | 5152 | { |
18d371d3 | 5153 | return cxx_eval_outermost_constant_expr (t, false, true, true, decl); |
09b42213 | 5154 | } |
5155 | ||
d2c63826 | 5156 | /* Helper routine for fold_simple function. Either return simplified |
5157 | expression T, otherwise NULL_TREE. | |
5158 | In contrast to cp_fully_fold, and to maybe_constant_value, we try to fold | |
5159 | even if we are within template-declaration. So be careful on call, as in | |
5160 | such case types can be undefined. */ | |
5161 | ||
5162 | static tree | |
5163 | fold_simple_1 (tree t) | |
5164 | { | |
5165 | tree op1; | |
5166 | enum tree_code code = TREE_CODE (t); | |
5167 | ||
5168 | switch (code) | |
5169 | { | |
5170 | case INTEGER_CST: | |
5171 | case REAL_CST: | |
5172 | case VECTOR_CST: | |
5173 | case FIXED_CST: | |
5174 | case COMPLEX_CST: | |
5175 | return t; | |
5176 | ||
5177 | case SIZEOF_EXPR: | |
5178 | return fold_sizeof_expr (t); | |
5179 | ||
5180 | case ABS_EXPR: | |
19b4138e | 5181 | case ABSU_EXPR: |
d2c63826 | 5182 | case CONJ_EXPR: |
5183 | case REALPART_EXPR: | |
5184 | case IMAGPART_EXPR: | |
5185 | case NEGATE_EXPR: | |
5186 | case BIT_NOT_EXPR: | |
5187 | case TRUTH_NOT_EXPR: | |
5188 | case NOP_EXPR: | |
5189 | case VIEW_CONVERT_EXPR: | |
5190 | case CONVERT_EXPR: | |
5191 | case FLOAT_EXPR: | |
5192 | case FIX_TRUNC_EXPR: | |
5193 | case FIXED_CONVERT_EXPR: | |
5194 | case ADDR_SPACE_CONVERT_EXPR: | |
5195 | ||
5196 | op1 = TREE_OPERAND (t, 0); | |
5197 | ||
5198 | t = const_unop (code, TREE_TYPE (t), op1); | |
5199 | if (!t) | |
5200 | return NULL_TREE; | |
5201 | ||
5202 | if (CONVERT_EXPR_CODE_P (code) | |
5203 | && TREE_OVERFLOW_P (t) && !TREE_OVERFLOW_P (op1)) | |
5204 | TREE_OVERFLOW (t) = false; | |
5205 | return t; | |
5206 | ||
5207 | default: | |
5208 | return NULL_TREE; | |
5209 | } | |
5210 | } | |
5211 | ||
5212 | /* If T is a simple constant expression, returns its simplified value. | |
6fe5fea9 | 5213 | Otherwise returns T. In contrast to maybe_constant_value we |
d2c63826 | 5214 | simplify only few operations on constant-expressions, and we don't |
5215 | try to simplify constexpressions. */ | |
5216 | ||
5217 | tree | |
5218 | fold_simple (tree t) | |
5219 | { | |
d2c63826 | 5220 | if (processing_template_decl) |
5221 | return t; | |
5222 | ||
6fe5fea9 | 5223 | tree r = fold_simple_1 (t); |
5224 | if (r) | |
5225 | return r; | |
d2c63826 | 5226 | |
6fe5fea9 | 5227 | return t; |
d2c63826 | 5228 | } |
5229 | ||
09b42213 | 5230 | /* If T is a constant expression, returns its reduced value. |
5231 | Otherwise, if T does not have TREE_CONSTANT set, returns T. | |
5232 | Otherwise, returns a version of T without TREE_CONSTANT. */ | |
5233 | ||
b601ad30 | 5234 | static GTY((deletable)) hash_map<tree, tree> *cv_cache; |
5235 | ||
5236 | tree | |
5237 | maybe_constant_value (tree t, tree decl) | |
09b42213 | 5238 | { |
5239 | tree r; | |
5240 | ||
7e1f8be4 | 5241 | if (!is_nondependent_constant_expression (t)) |
09b42213 | 5242 | { |
5243 | if (TREE_OVERFLOW_P (t)) | |
5244 | { | |
5245 | t = build_nop (TREE_TYPE (t), t); | |
5246 | TREE_CONSTANT (t) = false; | |
5247 | } | |
5248 | return t; | |
5249 | } | |
b601ad30 | 5250 | else if (CONSTANT_CLASS_P (t)) |
5251 | /* No caching or evaluation needed. */ | |
5252 | return t; | |
5253 | ||
5254 | if (cv_cache == NULL) | |
5255 | cv_cache = hash_map<tree, tree>::create_ggc (101); | |
5256 | if (tree *cached = cv_cache->get (t)) | |
5257 | return *cached; | |
09b42213 | 5258 | |
18d371d3 | 5259 | r = cxx_eval_outermost_constant_expr (t, true, true, false, decl); |
5e8689fb | 5260 | gcc_checking_assert (r == t |
5261 | || CONVERT_EXPR_P (t) | |
5262 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
5263 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
5264 | || !cp_tree_equal (r, t)); | |
b601ad30 | 5265 | cv_cache->put (t, r); |
09b42213 | 5266 | return r; |
5267 | } | |
5268 | ||
2a655a4c | 5269 | /* Dispose of the whole CV_CACHE. */ |
5270 | ||
5271 | static void | |
5272 | clear_cv_cache (void) | |
5273 | { | |
5274 | if (cv_cache != NULL) | |
5275 | cv_cache->empty (); | |
5276 | } | |
5277 | ||
f553d9f8 | 5278 | /* Dispose of the whole CV_CACHE and FOLD_CACHE. */ |
a0c919f7 | 5279 | |
5280 | void | |
f553d9f8 | 5281 | clear_cv_and_fold_caches (void) |
a0c919f7 | 5282 | { |
2a655a4c | 5283 | clear_cv_cache (); |
f553d9f8 | 5284 | clear_fold_cache (); |
a0c919f7 | 5285 | } |
5286 | ||
21131a05 | 5287 | /* Like maybe_constant_value but first fully instantiate the argument. |
5288 | ||
5289 | Note: this is equivalent to instantiate_non_dependent_expr_sfinae | |
006b503a | 5290 | (t, complain) followed by maybe_constant_value but is more efficient, |
5291 | because it calls instantiation_dependent_expression_p and | |
5292 | potential_constant_expression at most once. | |
5293 | ||
5294 | Callers should generally pass their active complain, or if they are in a | |
5295 | non-template, diagnosing context, they can use the default of | |
5296 | tf_warning_or_error. Callers that might be within a template context, don't | |
5297 | have a complain parameter, and aren't going to remember the result for long | |
5298 | (e.g. null_ptr_cst_p), can pass tf_none and deal with error_mark_node | |
5299 | appropriately. */ | |
21131a05 | 5300 | |
5301 | tree | |
006b503a | 5302 | fold_non_dependent_expr (tree t, |
5303 | tsubst_flags_t complain /* = tf_warning_or_error */) | |
21131a05 | 5304 | { |
5305 | if (t == NULL_TREE) | |
5306 | return NULL_TREE; | |
5307 | ||
5308 | /* If we're in a template, but T isn't value dependent, simplify | |
5309 | it. We're supposed to treat: | |
5310 | ||
5311 | template <typename T> void f(T[1 + 1]); | |
5312 | template <typename T> void f(T[2]); | |
5313 | ||
5314 | as two declarations of the same function, for example. */ | |
5315 | if (processing_template_decl) | |
5316 | { | |
7e1f8be4 | 5317 | if (is_nondependent_constant_expression (t)) |
21131a05 | 5318 | { |
c8a9f04c | 5319 | processing_template_decl_sentinel s; |
006b503a | 5320 | t = instantiate_non_dependent_expr_internal (t, complain); |
21131a05 | 5321 | |
5322 | if (type_unknown_p (t) | |
5323 | || BRACE_ENCLOSED_INITIALIZER_P (t)) | |
5324 | { | |
5325 | if (TREE_OVERFLOW_P (t)) | |
5326 | { | |
5327 | t = build_nop (TREE_TYPE (t), t); | |
5328 | TREE_CONSTANT (t) = false; | |
5329 | } | |
5330 | return t; | |
5331 | } | |
5332 | ||
18d371d3 | 5333 | tree r = cxx_eval_outermost_constant_expr (t, true, true, false, |
5334 | NULL_TREE); | |
21131a05 | 5335 | /* cp_tree_equal looks through NOPs, so allow them. */ |
5e8689fb | 5336 | gcc_checking_assert (r == t |
5337 | || CONVERT_EXPR_P (t) | |
5338 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
5339 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
5340 | || !cp_tree_equal (r, t)); | |
21131a05 | 5341 | return r; |
5342 | } | |
5343 | else if (TREE_OVERFLOW_P (t)) | |
5344 | { | |
5345 | t = build_nop (TREE_TYPE (t), t); | |
5346 | TREE_CONSTANT (t) = false; | |
5347 | } | |
5348 | return t; | |
5349 | } | |
5350 | ||
5351 | return maybe_constant_value (t); | |
5352 | } | |
5353 | ||
09b42213 | 5354 | /* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather |
18d371d3 | 5355 | than wrapped in a TARGET_EXPR. |
5356 | ALLOW_NON_CONSTANT is false if T is required to be a constant expression. | |
5357 | PRETEND_CONST_REQUIRED is true if T is required to be const-evaluated as | |
5358 | per P0595 even when ALLOW_NON_CONSTANT is true. */ | |
09b42213 | 5359 | |
0c703e14 | 5360 | static tree |
18d371d3 | 5361 | maybe_constant_init_1 (tree t, tree decl, bool allow_non_constant, |
5362 | bool pretend_const_required) | |
09b42213 | 5363 | { |
d2c63826 | 5364 | if (!t) |
5365 | return t; | |
09b42213 | 5366 | if (TREE_CODE (t) == EXPR_STMT) |
5367 | t = TREE_OPERAND (t, 0); | |
5368 | if (TREE_CODE (t) == CONVERT_EXPR | |
5369 | && VOID_TYPE_P (TREE_TYPE (t))) | |
5370 | t = TREE_OPERAND (t, 0); | |
9c96033c | 5371 | if (TREE_CODE (t) == INIT_EXPR) |
5372 | t = TREE_OPERAND (t, 1); | |
c6d97004 | 5373 | if (TREE_CODE (t) == TARGET_EXPR) |
5374 | t = TARGET_EXPR_INITIAL (t); | |
7e1f8be4 | 5375 | if (!is_nondependent_static_init_expression (t)) |
2055d27a | 5376 | /* Don't try to evaluate it. */; |
0c703e14 | 5377 | else if (CONSTANT_CLASS_P (t) && allow_non_constant) |
b601ad30 | 5378 | /* No evaluation needed. */; |
2055d27a | 5379 | else |
18d371d3 | 5380 | t = cxx_eval_outermost_constant_expr (t, allow_non_constant, |
fbe79a84 | 5381 | /*strict*/false, |
18d371d3 | 5382 | pretend_const_required, decl); |
09b42213 | 5383 | if (TREE_CODE (t) == TARGET_EXPR) |
5384 | { | |
5385 | tree init = TARGET_EXPR_INITIAL (t); | |
5386 | if (TREE_CODE (init) == CONSTRUCTOR) | |
5387 | t = init; | |
5388 | } | |
5389 | return t; | |
5390 | } | |
5391 | ||
0c703e14 | 5392 | /* Wrapper for maybe_constant_init_1 which permits non constants. */ |
5393 | ||
5394 | tree | |
18d371d3 | 5395 | maybe_constant_init (tree t, tree decl, bool pretend_const_required) |
0c703e14 | 5396 | { |
18d371d3 | 5397 | return maybe_constant_init_1 (t, decl, true, pretend_const_required); |
0c703e14 | 5398 | } |
5399 | ||
5400 | /* Wrapper for maybe_constant_init_1 which does not permit non constants. */ | |
5401 | ||
5402 | tree | |
5403 | cxx_constant_init (tree t, tree decl) | |
5404 | { | |
18d371d3 | 5405 | return maybe_constant_init_1 (t, decl, false, true); |
0c703e14 | 5406 | } |
5407 | ||
09b42213 | 5408 | #if 0 |
5409 | /* FIXME see ADDR_EXPR section in potential_constant_expression_1. */ | |
5410 | /* Return true if the object referred to by REF has automatic or thread | |
5411 | local storage. */ | |
5412 | ||
5413 | enum { ck_ok, ck_bad, ck_unknown }; | |
5414 | static int | |
5415 | check_automatic_or_tls (tree ref) | |
5416 | { | |
3754d046 | 5417 | machine_mode mode; |
81bc0f0f | 5418 | poly_int64 bitsize, bitpos; |
09b42213 | 5419 | tree offset; |
5420 | int volatilep = 0, unsignedp = 0; | |
5421 | tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset, | |
5422 | &mode, &unsignedp, &volatilep, false); | |
5423 | duration_kind dk; | |
5424 | ||
5425 | /* If there isn't a decl in the middle, we don't know the linkage here, | |
5426 | and this isn't a constant expression anyway. */ | |
5427 | if (!DECL_P (decl)) | |
5428 | return ck_unknown; | |
5429 | dk = decl_storage_duration (decl); | |
5430 | return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok; | |
5431 | } | |
5432 | #endif | |
5433 | ||
5434 | /* Return true if T denotes a potentially constant expression. Issue | |
5435 | diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true, | |
7e1f8be4 | 5436 | an lvalue-rvalue conversion is implied. If NOW is true, we want to |
5437 | consider the expression in the current context, independent of constexpr | |
5438 | substitution. | |
09b42213 | 5439 | |
5440 | C++0x [expr.const] used to say | |
5441 | ||
5442 | 6 An expression is a potential constant expression if it is | |
5443 | a constant expression where all occurrences of function | |
5444 | parameters are replaced by arbitrary constant expressions | |
5445 | of the appropriate type. | |
5446 | ||
5447 | 2 A conditional expression is a constant expression unless it | |
5448 | involves one of the following as a potentially evaluated | |
5449 | subexpression (3.2), but subexpressions of logical AND (5.14), | |
5450 | logical OR (5.15), and conditional (5.16) operations that are | |
5451 | not evaluated are not considered. */ | |
5452 | ||
5453 | static bool | |
7e1f8be4 | 5454 | potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, |
32fee334 | 5455 | tsubst_flags_t flags, tree *jump_target) |
09b42213 | 5456 | { |
7e1f8be4 | 5457 | #define RECUR(T,RV) \ |
32fee334 | 5458 | potential_constant_expression_1 ((T), (RV), strict, now, flags, jump_target) |
7e1f8be4 | 5459 | |
09b42213 | 5460 | enum { any = false, rval = true }; |
5461 | int i; | |
5462 | tree tmp; | |
5463 | ||
5464 | if (t == error_mark_node) | |
5465 | return false; | |
5466 | if (t == NULL_TREE) | |
5467 | return true; | |
d3a3cfb8 | 5468 | location_t loc = cp_expr_loc_or_loc (t, input_location); |
32fee334 | 5469 | |
5470 | if (*jump_target) | |
5471 | /* If we are jumping, ignore everything. This is simpler than the | |
5472 | cxx_eval_constant_expression handling because we only need to be | |
5473 | conservatively correct, and we don't necessarily have a constant value | |
5474 | available, so we don't bother with switch tracking. */ | |
5475 | return true; | |
5476 | ||
eade0940 | 5477 | if (TREE_THIS_VOLATILE (t) && !DECL_P (t)) |
09b42213 | 5478 | { |
5479 | if (flags & tf_error) | |
d6a08f5c | 5480 | error_at (loc, "expression %qE has side-effects", t); |
09b42213 | 5481 | return false; |
5482 | } | |
5483 | if (CONSTANT_CLASS_P (t)) | |
5484 | return true; | |
c7282bf2 | 5485 | if (CODE_CONTAINS_STRUCT (TREE_CODE (t), TS_TYPED) |
5486 | && TREE_TYPE (t) == error_mark_node) | |
5487 | return false; | |
09b42213 | 5488 | |
5489 | switch (TREE_CODE (t)) | |
5490 | { | |
5491 | case FUNCTION_DECL: | |
5492 | case BASELINK: | |
5493 | case TEMPLATE_DECL: | |
5494 | case OVERLOAD: | |
5495 | case TEMPLATE_ID_EXPR: | |
5496 | case LABEL_DECL: | |
5497 | case LABEL_EXPR: | |
9c96033c | 5498 | case CASE_LABEL_EXPR: |
09b42213 | 5499 | case CONST_DECL: |
5500 | case SIZEOF_EXPR: | |
5501 | case ALIGNOF_EXPR: | |
5502 | case OFFSETOF_EXPR: | |
5503 | case NOEXCEPT_EXPR: | |
5504 | case TEMPLATE_PARM_INDEX: | |
5505 | case TRAIT_EXPR: | |
5506 | case IDENTIFIER_NODE: | |
5507 | case USERDEF_LITERAL: | |
5508 | /* We can see a FIELD_DECL in a pointer-to-member expression. */ | |
5509 | case FIELD_DECL: | |
d2c63826 | 5510 | case RESULT_DECL: |
09b42213 | 5511 | case USING_DECL: |
9c96033c | 5512 | case USING_STMT: |
cf72f34d | 5513 | case PLACEHOLDER_EXPR: |
56c12fd4 | 5514 | case REQUIRES_EXPR: |
33603066 | 5515 | case STATIC_ASSERT: |
90567983 | 5516 | case DEBUG_BEGIN_STMT: |
09b42213 | 5517 | return true; |
5518 | ||
32fee334 | 5519 | case RETURN_EXPR: |
5520 | if (!RECUR (TREE_OPERAND (t, 0), any)) | |
5521 | return false; | |
5522 | /* FALLTHROUGH */ | |
5523 | ||
5524 | case BREAK_STMT: | |
5525 | case CONTINUE_STMT: | |
5526 | *jump_target = t; | |
5527 | return true; | |
5528 | ||
7e1f8be4 | 5529 | case PARM_DECL: |
5530 | if (now) | |
5531 | { | |
5532 | if (flags & tf_error) | |
5533 | error ("%qE is not a constant expression", t); | |
5534 | return false; | |
5535 | } | |
5536 | return true; | |
5537 | ||
09b42213 | 5538 | case AGGR_INIT_EXPR: |
5539 | case CALL_EXPR: | |
5540 | /* -- an invocation of a function other than a constexpr function | |
5541 | or a constexpr constructor. */ | |
5542 | { | |
5543 | tree fun = get_function_named_in_call (t); | |
5544 | const int nargs = call_expr_nargs (t); | |
5545 | i = 0; | |
5546 | ||
9c96033c | 5547 | if (fun == NULL_TREE) |
5548 | { | |
732905bb | 5549 | /* Reset to allow the function to continue past the end |
5550 | of the block below. Otherwise return early. */ | |
5551 | bool bail = true; | |
5552 | ||
32cf7025 | 5553 | if (TREE_CODE (t) == CALL_EXPR |
5554 | && CALL_EXPR_FN (t) == NULL_TREE) | |
5555 | switch (CALL_EXPR_IFN (t)) | |
5556 | { | |
5557 | /* These should be ignored, they are optimized away from | |
5558 | constexpr functions. */ | |
5559 | case IFN_UBSAN_NULL: | |
5560 | case IFN_UBSAN_BOUNDS: | |
5561 | case IFN_UBSAN_VPTR: | |
3c77f69c | 5562 | case IFN_FALLTHROUGH: |
32cf7025 | 5563 | return true; |
732905bb | 5564 | |
5565 | case IFN_ADD_OVERFLOW: | |
5566 | case IFN_SUB_OVERFLOW: | |
5567 | case IFN_MUL_OVERFLOW: | |
6e1b2ffb | 5568 | case IFN_LAUNDER: |
732905bb | 5569 | bail = false; |
5570 | ||
32cf7025 | 5571 | default: |
5572 | break; | |
5573 | } | |
732905bb | 5574 | |
5575 | if (bail) | |
5576 | { | |
5577 | /* fold_call_expr can't do anything with IFN calls. */ | |
5578 | if (flags & tf_error) | |
d6a08f5c | 5579 | error_at (loc, "call to internal function %qE", t); |
732905bb | 5580 | return false; |
5581 | } | |
9c96033c | 5582 | } |
732905bb | 5583 | |
5584 | if (fun && is_overloaded_fn (fun)) | |
09b42213 | 5585 | { |
5586 | if (TREE_CODE (fun) == FUNCTION_DECL) | |
5587 | { | |
5588 | if (builtin_valid_in_constant_expr_p (fun)) | |
5589 | return true; | |
5590 | if (!DECL_DECLARED_CONSTEXPR_P (fun) | |
5591 | /* Allow any built-in function; if the expansion | |
5592 | isn't constant, we'll deal with that then. */ | |
a0e9bfbb | 5593 | && !fndecl_built_in_p (fun)) |
09b42213 | 5594 | { |
5595 | if (flags & tf_error) | |
5596 | { | |
5967b28b | 5597 | error_at (loc, "call to non-%<constexpr%> function %qD", |
d6a08f5c | 5598 | fun); |
09b42213 | 5599 | explain_invalid_constexpr_fn (fun); |
5600 | } | |
5601 | return false; | |
5602 | } | |
5603 | /* A call to a non-static member function takes the address | |
5604 | of the object as the first argument. But in a constant | |
5605 | expression the address will be folded away, so look | |
5606 | through it now. */ | |
5607 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
5608 | && !DECL_CONSTRUCTOR_P (fun)) | |
5609 | { | |
5610 | tree x = get_nth_callarg (t, 0); | |
5611 | if (is_this_parameter (x)) | |
cf72f34d | 5612 | return true; |
7e1f8be4 | 5613 | /* Don't require an immediately constant value, as |
5614 | constexpr substitution might not use the value. */ | |
5615 | bool sub_now = false; | |
5616 | if (!potential_constant_expression_1 (x, rval, strict, | |
32fee334 | 5617 | sub_now, flags, |
5618 | jump_target)) | |
09b42213 | 5619 | return false; |
5620 | i = 1; | |
5621 | } | |
5622 | } | |
5623 | else | |
5624 | { | |
2055d27a | 5625 | if (!RECUR (fun, true)) |
09b42213 | 5626 | return false; |
5627 | fun = get_first_fn (fun); | |
5628 | } | |
5629 | /* Skip initial arguments to base constructors. */ | |
5630 | if (DECL_BASE_CONSTRUCTOR_P (fun)) | |
5631 | i = num_artificial_parms_for (fun); | |
5632 | fun = DECL_ORIGIN (fun); | |
5633 | } | |
732905bb | 5634 | else if (fun) |
09b42213 | 5635 | { |
2055d27a | 5636 | if (RECUR (fun, rval)) |
09b42213 | 5637 | /* Might end up being a constant function pointer. */; |
5638 | else | |
5639 | return false; | |
5640 | } | |
5641 | for (; i < nargs; ++i) | |
5642 | { | |
5643 | tree x = get_nth_callarg (t, i); | |
b2742b58 | 5644 | /* In a template, reference arguments haven't been converted to |
5645 | REFERENCE_TYPE and we might not even know if the parameter | |
5646 | is a reference, so accept lvalue constants too. */ | |
5647 | bool rv = processing_template_decl ? any : rval; | |
7e1f8be4 | 5648 | /* Don't require an immediately constant value, as constexpr |
5649 | substitution might not use the value of the argument. */ | |
5650 | bool sub_now = false; | |
5651 | if (!potential_constant_expression_1 (x, rv, strict, | |
32fee334 | 5652 | sub_now, flags, jump_target)) |
09b42213 | 5653 | return false; |
5654 | } | |
5655 | return true; | |
5656 | } | |
5657 | ||
5658 | case NON_LVALUE_EXPR: | |
5659 | /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to | |
5660 | -- an lvalue of integral type that refers to a non-volatile | |
5661 | const variable or static data member initialized with | |
5662 | constant expressions, or | |
5663 | ||
5664 | -- an lvalue of literal type that refers to non-volatile | |
5665 | object defined with constexpr, or that refers to a | |
5666 | sub-object of such an object; */ | |
2055d27a | 5667 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 5668 | |
5669 | case VAR_DECL: | |
9c8aeb66 | 5670 | if (DECL_HAS_VALUE_EXPR_P (t)) |
297de7bc | 5671 | { |
d0e2b7e7 | 5672 | if (now && is_normal_capture_proxy (t)) |
297de7bc | 5673 | { |
5674 | /* -- in a lambda-expression, a reference to this or to a | |
5675 | variable with automatic storage duration defined outside that | |
5676 | lambda-expression, where the reference would be an | |
5677 | odr-use. */ | |
5678 | if (flags & tf_error) | |
5679 | { | |
5680 | tree cap = DECL_CAPTURED_VARIABLE (t); | |
5681 | error ("lambda capture of %qE is not a constant expression", | |
5682 | cap); | |
5683 | if (!want_rval && decl_constant_var_p (cap)) | |
5684 | inform (input_location, "because it is used as a glvalue"); | |
5685 | } | |
5686 | return false; | |
5687 | } | |
5688 | return RECUR (DECL_VALUE_EXPR (t), rval); | |
5689 | } | |
2055d27a | 5690 | if (want_rval |
33603066 | 5691 | && !var_in_maybe_constexpr_fn (t) |
c7282bf2 | 5692 | && !type_dependent_expression_p (t) |
8d6486e1 | 5693 | && !decl_maybe_constant_var_p (t) |
2055d27a | 5694 | && (strict |
5695 | || !CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (t)) | |
8d6486e1 | 5696 | || (DECL_INITIAL (t) |
5697 | && !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (t))) | |
c7282bf2 | 5698 | && COMPLETE_TYPE_P (TREE_TYPE (t)) |
5699 | && !is_really_empty_class (TREE_TYPE (t))) | |
09b42213 | 5700 | { |
5701 | if (flags & tf_error) | |
5702 | non_const_var_error (t); | |
5703 | return false; | |
5704 | } | |
5705 | return true; | |
5706 | ||
5707 | case NOP_EXPR: | |
5708 | case CONVERT_EXPR: | |
5709 | case VIEW_CONVERT_EXPR: | |
5710 | /* -- a reinterpret_cast. FIXME not implemented, and this rule | |
5711 | may change to something more specific to type-punning (DR 1312). */ | |
5712 | { | |
5713 | tree from = TREE_OPERAND (t, 0); | |
d03fa520 | 5714 | if (INDIRECT_TYPE_P (TREE_TYPE (t)) |
09b42213 | 5715 | && TREE_CODE (from) == INTEGER_CST |
5716 | && !integer_zerop (from)) | |
5717 | { | |
5718 | if (flags & tf_error) | |
d6a08f5c | 5719 | error_at (loc, "reinterpret_cast from integer to pointer"); |
09b42213 | 5720 | return false; |
5721 | } | |
2055d27a | 5722 | return (RECUR (from, TREE_CODE (t) != VIEW_CONVERT_EXPR)); |
09b42213 | 5723 | } |
5724 | ||
cd45162d | 5725 | case ADDRESSOF_EXPR: |
5726 | /* This is like ADDR_EXPR, except it won't form pointer-to-member. */ | |
5727 | t = TREE_OPERAND (t, 0); | |
5728 | goto handle_addr_expr; | |
5729 | ||
09b42213 | 5730 | case ADDR_EXPR: |
5731 | /* -- a unary operator & that is applied to an lvalue that | |
5732 | designates an object with thread or automatic storage | |
5733 | duration; */ | |
5734 | t = TREE_OPERAND (t, 0); | |
5735 | ||
5736 | if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t)) | |
5737 | /* A pointer-to-member constant. */ | |
5738 | return true; | |
5739 | ||
cd45162d | 5740 | handle_addr_expr: |
09b42213 | 5741 | #if 0 |
5742 | /* FIXME adjust when issue 1197 is fully resolved. For now don't do | |
5743 | any checking here, as we might dereference the pointer later. If | |
5744 | we remove this code, also remove check_automatic_or_tls. */ | |
5745 | i = check_automatic_or_tls (t); | |
5746 | if (i == ck_ok) | |
5747 | return true; | |
5748 | if (i == ck_bad) | |
5749 | { | |
5750 | if (flags & tf_error) | |
5751 | error ("address-of an object %qE with thread local or " | |
5752 | "automatic storage is not a constant expression", t); | |
5753 | return false; | |
5754 | } | |
5755 | #endif | |
2055d27a | 5756 | return RECUR (t, any); |
09b42213 | 5757 | |
20b34a56 | 5758 | case REALPART_EXPR: |
5759 | case IMAGPART_EXPR: | |
09b42213 | 5760 | case COMPONENT_REF: |
5761 | case BIT_FIELD_REF: | |
5762 | case ARROW_EXPR: | |
5763 | case OFFSET_REF: | |
5764 | /* -- a class member access unless its postfix-expression is | |
5765 | of literal type or of pointer to literal type. */ | |
5766 | /* This test would be redundant, as it follows from the | |
5767 | postfix-expression being a potential constant expression. */ | |
eade0940 | 5768 | if (type_unknown_p (t)) |
5769 | return true; | |
2055d27a | 5770 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5771 | |
5772 | case EXPR_PACK_EXPANSION: | |
2055d27a | 5773 | return RECUR (PACK_EXPANSION_PATTERN (t), want_rval); |
09b42213 | 5774 | |
5775 | case INDIRECT_REF: | |
5776 | { | |
5777 | tree x = TREE_OPERAND (t, 0); | |
5778 | STRIP_NOPS (x); | |
997bbf70 | 5779 | if (is_this_parameter (x) && !is_capture_proxy (x)) |
09b42213 | 5780 | { |
b7e4a558 | 5781 | if (!var_in_maybe_constexpr_fn (x)) |
09b42213 | 5782 | { |
5783 | if (flags & tf_error) | |
d6a08f5c | 5784 | error_at (loc, "use of %<this%> in a constant expression"); |
09b42213 | 5785 | return false; |
5786 | } | |
09b42213 | 5787 | return true; |
5788 | } | |
2055d27a | 5789 | return RECUR (x, rval); |
09b42213 | 5790 | } |
5791 | ||
9c96033c | 5792 | case STATEMENT_LIST: |
5793 | { | |
5794 | tree_stmt_iterator i; | |
5795 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
5796 | { | |
2055d27a | 5797 | if (!RECUR (tsi_stmt (i), any)) |
9c96033c | 5798 | return false; |
5799 | } | |
5800 | return true; | |
5801 | } | |
5802 | break; | |
5803 | ||
5804 | case MODIFY_EXPR: | |
5805 | if (cxx_dialect < cxx14) | |
5806 | goto fail; | |
2055d27a | 5807 | if (!RECUR (TREE_OPERAND (t, 0), any)) |
9c96033c | 5808 | return false; |
2055d27a | 5809 | if (!RECUR (TREE_OPERAND (t, 1), rval)) |
9c96033c | 5810 | return false; |
5811 | return true; | |
5812 | ||
5813 | case MODOP_EXPR: | |
5814 | if (cxx_dialect < cxx14) | |
5815 | goto fail; | |
2055d27a | 5816 | if (!RECUR (TREE_OPERAND (t, 0), rval)) |
9c96033c | 5817 | return false; |
2055d27a | 5818 | if (!RECUR (TREE_OPERAND (t, 2), rval)) |
9c96033c | 5819 | return false; |
5820 | return true; | |
5821 | ||
9c96033c | 5822 | case DO_STMT: |
2055d27a | 5823 | if (!RECUR (DO_COND (t), rval)) |
9c96033c | 5824 | return false; |
2055d27a | 5825 | if (!RECUR (DO_BODY (t), any)) |
9c96033c | 5826 | return false; |
32fee334 | 5827 | if (breaks (jump_target) || continues (jump_target)) |
5828 | *jump_target = NULL_TREE; | |
9c96033c | 5829 | return true; |
5830 | ||
5831 | case FOR_STMT: | |
2055d27a | 5832 | if (!RECUR (FOR_INIT_STMT (t), any)) |
9c96033c | 5833 | return false; |
10811950 | 5834 | tmp = FOR_COND (t); |
5835 | if (!RECUR (tmp, rval)) | |
9c96033c | 5836 | return false; |
10811950 | 5837 | if (tmp) |
5838 | { | |
5839 | if (!processing_template_decl) | |
5840 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
f807ff66 | 5841 | /* If we couldn't evaluate the condition, it might not ever be |
5842 | true. */ | |
5843 | if (!integer_onep (tmp)) | |
10811950 | 5844 | return true; |
5845 | } | |
2055d27a | 5846 | if (!RECUR (FOR_EXPR (t), any)) |
9c96033c | 5847 | return false; |
2055d27a | 5848 | if (!RECUR (FOR_BODY (t), any)) |
9c96033c | 5849 | return false; |
32fee334 | 5850 | if (breaks (jump_target) || continues (jump_target)) |
5851 | *jump_target = NULL_TREE; | |
9c96033c | 5852 | return true; |
5853 | ||
33603066 | 5854 | case RANGE_FOR_STMT: |
f4416678 | 5855 | if (!RECUR (RANGE_FOR_INIT_STMT (t), any)) |
5856 | return false; | |
33603066 | 5857 | if (!RECUR (RANGE_FOR_EXPR (t), any)) |
5858 | return false; | |
5859 | if (!RECUR (RANGE_FOR_BODY (t), any)) | |
5860 | return false; | |
32fee334 | 5861 | if (breaks (jump_target) || continues (jump_target)) |
5862 | *jump_target = NULL_TREE; | |
33603066 | 5863 | return true; |
5864 | ||
9c96033c | 5865 | case WHILE_STMT: |
10811950 | 5866 | tmp = WHILE_COND (t); |
5867 | if (!RECUR (tmp, rval)) | |
9c96033c | 5868 | return false; |
10811950 | 5869 | if (!processing_template_decl) |
5870 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
f807ff66 | 5871 | /* If we couldn't evaluate the condition, it might not ever be true. */ |
5872 | if (!integer_onep (tmp)) | |
10811950 | 5873 | return true; |
2055d27a | 5874 | if (!RECUR (WHILE_BODY (t), any)) |
9c96033c | 5875 | return false; |
32fee334 | 5876 | if (breaks (jump_target) || continues (jump_target)) |
5877 | *jump_target = NULL_TREE; | |
9c96033c | 5878 | return true; |
5879 | ||
5880 | case SWITCH_STMT: | |
2055d27a | 5881 | if (!RECUR (SWITCH_STMT_COND (t), rval)) |
9c96033c | 5882 | return false; |
748c426a | 5883 | /* FIXME we don't check SWITCH_STMT_BODY currently, because even |
5884 | unreachable labels would be checked. */ | |
9c96033c | 5885 | return true; |
5886 | ||
da7981e0 | 5887 | case STMT_EXPR: |
2055d27a | 5888 | return RECUR (STMT_EXPR_STMT (t), rval); |
da7981e0 | 5889 | |
09b42213 | 5890 | case LAMBDA_EXPR: |
27db1f50 | 5891 | if (cxx_dialect >= cxx17) |
5892 | /* In C++17 lambdas can be constexpr, don't give up yet. */ | |
5893 | return true; | |
5894 | else if (flags & tf_error) | |
5895 | error_at (loc, "lambda-expression is not a constant expression " | |
5896 | "before C++17"); | |
5897 | return false; | |
5898 | ||
09b42213 | 5899 | case DYNAMIC_CAST_EXPR: |
5900 | case PSEUDO_DTOR_EXPR: | |
09b42213 | 5901 | case NEW_EXPR: |
5902 | case VEC_NEW_EXPR: | |
5903 | case DELETE_EXPR: | |
5904 | case VEC_DELETE_EXPR: | |
5905 | case THROW_EXPR: | |
d6a08f5c | 5906 | case OMP_PARALLEL: |
5907 | case OMP_TASK: | |
5908 | case OMP_FOR: | |
83728168 | 5909 | case OMP_SIMD: |
d6a08f5c | 5910 | case OMP_DISTRIBUTE: |
5911 | case OMP_TASKLOOP: | |
5912 | case OMP_TEAMS: | |
5913 | case OMP_TARGET_DATA: | |
5914 | case OMP_TARGET: | |
5915 | case OMP_SECTIONS: | |
5916 | case OMP_ORDERED: | |
5917 | case OMP_CRITICAL: | |
5918 | case OMP_SINGLE: | |
5919 | case OMP_SECTION: | |
5920 | case OMP_MASTER: | |
5921 | case OMP_TASKGROUP: | |
5922 | case OMP_TARGET_UPDATE: | |
5923 | case OMP_TARGET_ENTER_DATA: | |
5924 | case OMP_TARGET_EXIT_DATA: | |
09b42213 | 5925 | case OMP_ATOMIC: |
5926 | case OMP_ATOMIC_READ: | |
5927 | case OMP_ATOMIC_CAPTURE_OLD: | |
5928 | case OMP_ATOMIC_CAPTURE_NEW: | |
7e5a76c8 | 5929 | case OMP_DEPOBJ: |
d6a08f5c | 5930 | case OACC_PARALLEL: |
5931 | case OACC_KERNELS: | |
5932 | case OACC_DATA: | |
5933 | case OACC_HOST_DATA: | |
5934 | case OACC_LOOP: | |
5935 | case OACC_CACHE: | |
5936 | case OACC_DECLARE: | |
5937 | case OACC_ENTER_DATA: | |
5938 | case OACC_EXIT_DATA: | |
5939 | case OACC_UPDATE: | |
09b42213 | 5940 | /* GCC internal stuff. */ |
5941 | case VA_ARG_EXPR: | |
09b42213 | 5942 | case TRANSACTION_EXPR: |
9c96033c | 5943 | case ASM_EXPR: |
9abecca2 | 5944 | case AT_ENCODE_EXPR: |
9c96033c | 5945 | fail: |
09b42213 | 5946 | if (flags & tf_error) |
d6a08f5c | 5947 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 5948 | return false; |
5949 | ||
bb6e576c | 5950 | case OBJ_TYPE_REF: |
5951 | if (cxx_dialect >= cxx2a) | |
5952 | /* In C++2a virtual calls can be constexpr, don't give up yet. */ | |
5953 | return true; | |
5954 | else if (flags & tf_error) | |
5955 | error_at (loc, "virtual functions cannot be constexpr before C++2a"); | |
5956 | return false; | |
5957 | ||
09b42213 | 5958 | case TYPEID_EXPR: |
5959 | /* -- a typeid expression whose operand is of polymorphic | |
5960 | class type; */ | |
5961 | { | |
5962 | tree e = TREE_OPERAND (t, 0); | |
5963 | if (!TYPE_P (e) && !type_dependent_expression_p (e) | |
5964 | && TYPE_POLYMORPHIC_P (TREE_TYPE (e))) | |
5965 | { | |
5966 | if (flags & tf_error) | |
d6a08f5c | 5967 | error_at (loc, "typeid-expression is not a constant expression " |
5968 | "because %qE is of polymorphic type", e); | |
09b42213 | 5969 | return false; |
5970 | } | |
5971 | return true; | |
5972 | } | |
5973 | ||
57e83b58 | 5974 | case POINTER_DIFF_EXPR: |
09b42213 | 5975 | case MINUS_EXPR: |
09b42213 | 5976 | want_rval = true; |
5977 | goto binary; | |
5978 | ||
5979 | case LT_EXPR: | |
5980 | case LE_EXPR: | |
5981 | case GT_EXPR: | |
5982 | case GE_EXPR: | |
5983 | case EQ_EXPR: | |
5984 | case NE_EXPR: | |
09b42213 | 5985 | want_rval = true; |
5986 | goto binary; | |
5987 | ||
9c96033c | 5988 | case PREINCREMENT_EXPR: |
5989 | case POSTINCREMENT_EXPR: | |
5990 | case PREDECREMENT_EXPR: | |
5991 | case POSTDECREMENT_EXPR: | |
5992 | if (cxx_dialect < cxx14) | |
5993 | goto fail; | |
5994 | goto unary; | |
5995 | ||
09b42213 | 5996 | case BIT_NOT_EXPR: |
5997 | /* A destructor. */ | |
5998 | if (TYPE_P (TREE_OPERAND (t, 0))) | |
5999 | return true; | |
e3533433 | 6000 | /* fall through. */ |
09b42213 | 6001 | |
09b42213 | 6002 | case CONJ_EXPR: |
6003 | case SAVE_EXPR: | |
6004 | case FIX_TRUNC_EXPR: | |
6005 | case FLOAT_EXPR: | |
6006 | case NEGATE_EXPR: | |
6007 | case ABS_EXPR: | |
1c67942e | 6008 | case ABSU_EXPR: |
09b42213 | 6009 | case TRUTH_NOT_EXPR: |
6010 | case FIXED_CONVERT_EXPR: | |
6011 | case UNARY_PLUS_EXPR: | |
6fdf70f5 | 6012 | case UNARY_LEFT_FOLD_EXPR: |
6013 | case UNARY_RIGHT_FOLD_EXPR: | |
9c96033c | 6014 | unary: |
2055d27a | 6015 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 6016 | |
6017 | case CAST_EXPR: | |
6018 | case CONST_CAST_EXPR: | |
6019 | case STATIC_CAST_EXPR: | |
6020 | case REINTERPRET_CAST_EXPR: | |
6021 | case IMPLICIT_CONV_EXPR: | |
6022 | if (cxx_dialect < cxx11 | |
6023 | && !dependent_type_p (TREE_TYPE (t)) | |
6024 | && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t))) | |
6025 | /* In C++98, a conversion to non-integral type can't be part of a | |
6026 | constant expression. */ | |
6027 | { | |
6028 | if (flags & tf_error) | |
d6a08f5c | 6029 | error_at (loc, |
6030 | "cast to non-integral type %qT in a constant expression", | |
6031 | TREE_TYPE (t)); | |
09b42213 | 6032 | return false; |
6033 | } | |
e0ccd480 | 6034 | /* This might be a conversion from a class to a (potentially) literal |
6035 | type. Let's consider it potentially constant since the conversion | |
6036 | might be a constexpr user-defined conversion. */ | |
6037 | else if (cxx_dialect >= cxx11 | |
6038 | && (dependent_type_p (TREE_TYPE (t)) | |
6039 | || !COMPLETE_TYPE_P (TREE_TYPE (t)) | |
6040 | || literal_type_p (TREE_TYPE (t))) | |
6041 | && TREE_OPERAND (t, 0)) | |
6042 | { | |
6043 | tree type = TREE_TYPE (TREE_OPERAND (t, 0)); | |
6044 | /* If this is a dependent type, it could end up being a class | |
6045 | with conversions. */ | |
6046 | if (type == NULL_TREE || WILDCARD_TYPE_P (type)) | |
6047 | return true; | |
6048 | /* Or a non-dependent class which has conversions. */ | |
6049 | else if (CLASS_TYPE_P (type) | |
6050 | && (TYPE_HAS_CONVERSION (type) || dependent_scope_p (type))) | |
6051 | return true; | |
6052 | } | |
09b42213 | 6053 | |
2055d27a | 6054 | return (RECUR (TREE_OPERAND (t, 0), |
90ad495b | 6055 | !TYPE_REF_P (TREE_TYPE (t)))); |
09b42213 | 6056 | |
9c96033c | 6057 | case BIND_EXPR: |
2055d27a | 6058 | return RECUR (BIND_EXPR_BODY (t), want_rval); |
9c96033c | 6059 | |
9c96033c | 6060 | case CLEANUP_POINT_EXPR: |
6061 | case MUST_NOT_THROW_EXPR: | |
6062 | case TRY_CATCH_EXPR: | |
7f67d68c | 6063 | case TRY_BLOCK: |
9c96033c | 6064 | case EH_SPEC_BLOCK: |
6065 | case EXPR_STMT: | |
09b42213 | 6066 | case PAREN_EXPR: |
6067 | case NON_DEPENDENT_EXPR: | |
6068 | /* For convenience. */ | |
d1980671 | 6069 | case LOOP_EXPR: |
6070 | case EXIT_EXPR: | |
2055d27a | 6071 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 6072 | |
33603066 | 6073 | case DECL_EXPR: |
6074 | tmp = DECL_EXPR_DECL (t); | |
6075 | if (VAR_P (tmp) && !DECL_ARTIFICIAL (tmp)) | |
6076 | { | |
6077 | if (TREE_STATIC (tmp)) | |
6078 | { | |
6079 | if (flags & tf_error) | |
6080 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 6081 | "%<static%> in %<constexpr%> context", tmp); |
33603066 | 6082 | return false; |
6083 | } | |
6084 | else if (CP_DECL_THREAD_LOCAL_P (tmp)) | |
6085 | { | |
6086 | if (flags & tf_error) | |
6087 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 6088 | "%<thread_local%> in %<constexpr%> context", tmp); |
33603066 | 6089 | return false; |
6090 | } | |
282ea908 | 6091 | else if (!check_for_uninitialized_const_var |
6092 | (tmp, /*constexpr_context_p=*/true, flags)) | |
6093 | return false; | |
33603066 | 6094 | } |
6095 | return RECUR (tmp, want_rval); | |
6096 | ||
7f67d68c | 6097 | case TRY_FINALLY_EXPR: |
6098 | return (RECUR (TREE_OPERAND (t, 0), want_rval) | |
6099 | && RECUR (TREE_OPERAND (t, 1), any)); | |
6100 | ||
09b42213 | 6101 | case SCOPE_REF: |
2055d27a | 6102 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 6103 | |
6104 | case TARGET_EXPR: | |
07d8961c | 6105 | if (!TARGET_EXPR_DIRECT_INIT_P (t) |
6106 | && !literal_type_p (TREE_TYPE (t))) | |
09b42213 | 6107 | { |
6108 | if (flags & tf_error) | |
6109 | { | |
bc35ef65 | 6110 | auto_diagnostic_group d; |
d6a08f5c | 6111 | error_at (loc, "temporary of non-literal type %qT in a " |
6112 | "constant expression", TREE_TYPE (t)); | |
09b42213 | 6113 | explain_non_literal_class (TREE_TYPE (t)); |
6114 | } | |
6115 | return false; | |
6116 | } | |
e3533433 | 6117 | /* FALLTHRU */ |
09b42213 | 6118 | case INIT_EXPR: |
2055d27a | 6119 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 6120 | |
6121 | case CONSTRUCTOR: | |
6122 | { | |
6123 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
6124 | constructor_elt *ce; | |
6125 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2055d27a | 6126 | if (!RECUR (ce->value, want_rval)) |
09b42213 | 6127 | return false; |
6128 | return true; | |
6129 | } | |
6130 | ||
6131 | case TREE_LIST: | |
6132 | { | |
6133 | gcc_assert (TREE_PURPOSE (t) == NULL_TREE | |
6134 | || DECL_P (TREE_PURPOSE (t))); | |
2055d27a | 6135 | if (!RECUR (TREE_VALUE (t), want_rval)) |
09b42213 | 6136 | return false; |
6137 | if (TREE_CHAIN (t) == NULL_TREE) | |
6138 | return true; | |
2055d27a | 6139 | return RECUR (TREE_CHAIN (t), want_rval); |
09b42213 | 6140 | } |
6141 | ||
6142 | case TRUNC_DIV_EXPR: | |
6143 | case CEIL_DIV_EXPR: | |
6144 | case FLOOR_DIV_EXPR: | |
6145 | case ROUND_DIV_EXPR: | |
6146 | case TRUNC_MOD_EXPR: | |
6147 | case CEIL_MOD_EXPR: | |
6148 | case ROUND_MOD_EXPR: | |
6149 | { | |
6150 | tree denom = TREE_OPERAND (t, 1); | |
2055d27a | 6151 | if (!RECUR (denom, rval)) |
09b42213 | 6152 | return false; |
6153 | /* We can't call cxx_eval_outermost_constant_expr on an expression | |
21131a05 | 6154 | that hasn't been through instantiate_non_dependent_expr yet. */ |
09b42213 | 6155 | if (!processing_template_decl) |
6156 | denom = cxx_eval_outermost_constant_expr (denom, true); | |
6157 | if (integer_zerop (denom)) | |
6158 | { | |
6159 | if (flags & tf_error) | |
ea034e2c | 6160 | error ("division by zero is not a constant expression"); |
09b42213 | 6161 | return false; |
6162 | } | |
6163 | else | |
6164 | { | |
6165 | want_rval = true; | |
2055d27a | 6166 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 6167 | } |
6168 | } | |
6169 | ||
6170 | case COMPOUND_EXPR: | |
6171 | { | |
6172 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
6173 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
6174 | introduced by build_call_a. */ | |
6175 | tree op0 = TREE_OPERAND (t, 0); | |
6176 | tree op1 = TREE_OPERAND (t, 1); | |
6177 | STRIP_NOPS (op1); | |
6178 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
6179 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
2055d27a | 6180 | return RECUR (op0, want_rval); |
09b42213 | 6181 | else |
6182 | goto binary; | |
6183 | } | |
6184 | ||
6185 | /* If the first operand is the non-short-circuit constant, look at | |
6186 | the second operand; otherwise we only care about the first one for | |
6187 | potentiality. */ | |
6188 | case TRUTH_AND_EXPR: | |
6189 | case TRUTH_ANDIF_EXPR: | |
6190 | tmp = boolean_true_node; | |
6191 | goto truth; | |
6192 | case TRUTH_OR_EXPR: | |
6193 | case TRUTH_ORIF_EXPR: | |
6194 | tmp = boolean_false_node; | |
6195 | truth: | |
6196 | { | |
6197 | tree op = TREE_OPERAND (t, 0); | |
2055d27a | 6198 | if (!RECUR (op, rval)) |
09b42213 | 6199 | return false; |
6200 | if (!processing_template_decl) | |
6201 | op = cxx_eval_outermost_constant_expr (op, true); | |
6202 | if (tree_int_cst_equal (op, tmp)) | |
2055d27a | 6203 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 6204 | else |
6205 | return true; | |
6206 | } | |
6207 | ||
6208 | case PLUS_EXPR: | |
6209 | case MULT_EXPR: | |
6210 | case POINTER_PLUS_EXPR: | |
6211 | case RDIV_EXPR: | |
6212 | case EXACT_DIV_EXPR: | |
6213 | case MIN_EXPR: | |
6214 | case MAX_EXPR: | |
6215 | case LSHIFT_EXPR: | |
6216 | case RSHIFT_EXPR: | |
6217 | case LROTATE_EXPR: | |
6218 | case RROTATE_EXPR: | |
6219 | case BIT_IOR_EXPR: | |
6220 | case BIT_XOR_EXPR: | |
6221 | case BIT_AND_EXPR: | |
6222 | case TRUTH_XOR_EXPR: | |
6223 | case UNORDERED_EXPR: | |
6224 | case ORDERED_EXPR: | |
6225 | case UNLT_EXPR: | |
6226 | case UNLE_EXPR: | |
6227 | case UNGT_EXPR: | |
6228 | case UNGE_EXPR: | |
6229 | case UNEQ_EXPR: | |
6230 | case LTGT_EXPR: | |
6231 | case RANGE_EXPR: | |
6232 | case COMPLEX_EXPR: | |
6233 | want_rval = true; | |
6234 | /* Fall through. */ | |
6235 | case ARRAY_REF: | |
6236 | case ARRAY_RANGE_REF: | |
6237 | case MEMBER_REF: | |
6238 | case DOTSTAR_EXPR: | |
f0abe78f | 6239 | case MEM_REF: |
6fdf70f5 | 6240 | case BINARY_LEFT_FOLD_EXPR: |
6241 | case BINARY_RIGHT_FOLD_EXPR: | |
09b42213 | 6242 | binary: |
6243 | for (i = 0; i < 2; ++i) | |
2055d27a | 6244 | if (!RECUR (TREE_OPERAND (t, i), want_rval)) |
09b42213 | 6245 | return false; |
6246 | return true; | |
6247 | ||
09b42213 | 6248 | case VEC_PERM_EXPR: |
6249 | for (i = 0; i < 3; ++i) | |
2055d27a | 6250 | if (!RECUR (TREE_OPERAND (t, i), true)) |
09b42213 | 6251 | return false; |
6252 | return true; | |
6253 | ||
6254 | case COND_EXPR: | |
b0fe8b95 | 6255 | if (COND_EXPR_IS_VEC_DELETE (t)) |
6256 | { | |
6257 | if (flags & tf_error) | |
d6a08f5c | 6258 | error_at (loc, "%<delete[]%> is not a constant expression"); |
b0fe8b95 | 6259 | return false; |
6260 | } | |
6261 | /* Fall through. */ | |
6262 | case IF_STMT: | |
09b42213 | 6263 | case VEC_COND_EXPR: |
6264 | /* If the condition is a known constant, we know which of the legs we | |
6265 | care about; otherwise we only require that the condition and | |
6266 | either of the legs be potentially constant. */ | |
6267 | tmp = TREE_OPERAND (t, 0); | |
2055d27a | 6268 | if (!RECUR (tmp, rval)) |
09b42213 | 6269 | return false; |
6270 | if (!processing_template_decl) | |
6271 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
6272 | if (integer_zerop (tmp)) | |
2055d27a | 6273 | return RECUR (TREE_OPERAND (t, 2), want_rval); |
09b42213 | 6274 | else if (TREE_CODE (tmp) == INTEGER_CST) |
2055d27a | 6275 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 6276 | for (i = 1; i < 3; ++i) |
6277 | if (potential_constant_expression_1 (TREE_OPERAND (t, i), | |
32fee334 | 6278 | want_rval, strict, now, |
6279 | tf_none, jump_target)) | |
09b42213 | 6280 | return true; |
6281 | if (flags & tf_error) | |
d6a08f5c | 6282 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 6283 | return false; |
6284 | ||
6285 | case VEC_INIT_EXPR: | |
6286 | if (VEC_INIT_EXPR_IS_CONSTEXPR (t)) | |
6287 | return true; | |
6288 | if (flags & tf_error) | |
6289 | { | |
d6a08f5c | 6290 | error_at (loc, "non-constant array initialization"); |
09b42213 | 6291 | diagnose_non_constexpr_vec_init (t); |
6292 | } | |
6293 | return false; | |
6294 | ||
db1ae94f | 6295 | case TYPE_DECL: |
6296 | case TAG_DEFN: | |
6297 | /* We can see these in statement-expressions. */ | |
6298 | return true; | |
6299 | ||
fd130325 | 6300 | case CLEANUP_STMT: |
d2c63826 | 6301 | case EMPTY_CLASS_EXPR: |
38ef3642 | 6302 | case PREDICT_EXPR: |
d2c63826 | 6303 | return false; |
6304 | ||
d1980671 | 6305 | case GOTO_EXPR: |
6306 | { | |
6307 | tree *target = &TREE_OPERAND (t, 0); | |
d40a1eac | 6308 | /* Gotos representing break and continue are OK. */ |
6309 | if (breaks (target) || continues (target)) | |
32fee334 | 6310 | { |
6311 | *jump_target = *target; | |
6312 | return true; | |
6313 | } | |
d40a1eac | 6314 | if (flags & tf_error) |
d6a08f5c | 6315 | error_at (loc, "%<goto%> is not a constant expression"); |
d40a1eac | 6316 | return false; |
d1980671 | 6317 | } |
6318 | ||
24c6ee98 | 6319 | case ANNOTATE_EXPR: |
24c6ee98 | 6320 | return RECUR (TREE_OPERAND (t, 0), rval); |
6321 | ||
09b42213 | 6322 | default: |
6323 | if (objc_is_property_ref (t)) | |
6324 | return false; | |
6325 | ||
6326 | sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t))); | |
d40a1eac | 6327 | gcc_unreachable (); |
09b42213 | 6328 | return false; |
6329 | } | |
2055d27a | 6330 | #undef RECUR |
09b42213 | 6331 | } |
6332 | ||
32fee334 | 6333 | bool |
6334 | potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, | |
6335 | tsubst_flags_t flags) | |
6336 | { | |
6337 | tree target = NULL_TREE; | |
6338 | return potential_constant_expression_1 (t, want_rval, strict, now, | |
6339 | flags, &target); | |
6340 | } | |
6341 | ||
09b42213 | 6342 | /* The main entry point to the above. */ |
6343 | ||
6344 | bool | |
6345 | potential_constant_expression (tree t) | |
6346 | { | |
7e1f8be4 | 6347 | return potential_constant_expression_1 (t, false, true, false, tf_none); |
09b42213 | 6348 | } |
6349 | ||
6350 | /* As above, but require a constant rvalue. */ | |
6351 | ||
6352 | bool | |
6353 | potential_rvalue_constant_expression (tree t) | |
6354 | { | |
7e1f8be4 | 6355 | return potential_constant_expression_1 (t, true, true, false, tf_none); |
09b42213 | 6356 | } |
6357 | ||
6358 | /* Like above, but complain about non-constant expressions. */ | |
6359 | ||
6360 | bool | |
6361 | require_potential_constant_expression (tree t) | |
6362 | { | |
786721dc | 6363 | return potential_constant_expression_1 (t, false, true, false, |
6364 | tf_warning_or_error); | |
09b42213 | 6365 | } |
6366 | ||
6367 | /* Cross product of the above. */ | |
6368 | ||
6369 | bool | |
6370 | require_potential_rvalue_constant_expression (tree t) | |
6371 | { | |
786721dc | 6372 | return potential_constant_expression_1 (t, true, true, false, |
6373 | tf_warning_or_error); | |
6374 | } | |
6375 | ||
6376 | /* Like above, but don't consider PARM_DECL a potential_constant_expression. */ | |
6377 | ||
6378 | bool | |
6379 | require_rvalue_constant_expression (tree t) | |
6380 | { | |
6381 | return potential_constant_expression_1 (t, true, true, true, | |
6382 | tf_warning_or_error); | |
7e1f8be4 | 6383 | } |
6384 | ||
6385 | /* Like potential_constant_expression, but don't consider possible constexpr | |
6386 | substitution of the current function. That is, PARM_DECL qualifies under | |
6387 | potential_constant_expression, but not here. | |
6388 | ||
6389 | This is basically what you can check when any actual constant values might | |
6390 | be value-dependent. */ | |
6391 | ||
6392 | bool | |
6393 | is_constant_expression (tree t) | |
6394 | { | |
6395 | return potential_constant_expression_1 (t, false, true, true, tf_none); | |
6396 | } | |
6397 | ||
6398 | /* Like above, but complain about non-constant expressions. */ | |
6399 | ||
6400 | bool | |
6401 | require_constant_expression (tree t) | |
6402 | { | |
6403 | return potential_constant_expression_1 (t, false, true, true, | |
6404 | tf_warning_or_error); | |
6405 | } | |
6406 | ||
6407 | /* Like is_constant_expression, but allow const variables that are not allowed | |
6408 | under constexpr rules. */ | |
6409 | ||
6410 | bool | |
6411 | is_static_init_expression (tree t) | |
6412 | { | |
6413 | return potential_constant_expression_1 (t, false, false, true, tf_none); | |
09b42213 | 6414 | } |
6415 | ||
29cf24ec | 6416 | /* Returns true if T is a potential constant expression that is not |
6417 | instantiation-dependent, and therefore a candidate for constant folding even | |
6418 | in a template. */ | |
6419 | ||
6420 | bool | |
7e1f8be4 | 6421 | is_nondependent_constant_expression (tree t) |
29cf24ec | 6422 | { |
6423 | return (!type_unknown_p (t) | |
6424 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6425 | && is_constant_expression (t) |
29cf24ec | 6426 | && !instantiation_dependent_expression_p (t)); |
6427 | } | |
6428 | ||
6429 | /* Returns true if T is a potential static initializer expression that is not | |
6430 | instantiation-dependent. */ | |
6431 | ||
6432 | bool | |
7e1f8be4 | 6433 | is_nondependent_static_init_expression (tree t) |
29cf24ec | 6434 | { |
6435 | return (!type_unknown_p (t) | |
6436 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6437 | && is_static_init_expression (t) |
29cf24ec | 6438 | && !instantiation_dependent_expression_p (t)); |
6439 | } | |
6440 | ||
a050099a | 6441 | /* Finalize constexpr processing after parsing. */ |
6442 | ||
6443 | void | |
6444 | fini_constexpr (void) | |
6445 | { | |
6446 | /* The contexpr call and fundef copies tables are no longer needed. */ | |
6447 | constexpr_call_table = NULL; | |
6448 | fundef_copies_table = NULL; | |
6449 | } | |
6450 | ||
09b42213 | 6451 | #include "gt-cp-constexpr.h" |