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f9885b8a | 1 | /* Perform -*- C++ -*- constant expression evaluation, including calls to |
2 | constexpr functions. These routines are used both during actual parsing | |
09b42213 | 3 | and during the instantiation of template functions. |
4 | ||
8e8f6434 | 5 | Copyright (C) 1998-2018 Free Software Foundation, Inc. |
09b42213 | 6 | |
7 | This file is part of GCC. | |
8 | ||
9 | GCC is free software; you can redistribute it and/or modify it | |
10 | under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 3, or (at your option) | |
12 | any later version. | |
13 | ||
14 | GCC is distributed in the hope that it will be useful, but | |
15 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
20 | along with GCC; see the file COPYING3. If not see | |
21 | <http://www.gnu.org/licenses/>. */ | |
22 | ||
23 | #include "config.h" | |
24 | #include "system.h" | |
25 | #include "coretypes.h" | |
09b42213 | 26 | #include "cp-tree.h" |
4cba6f60 | 27 | #include "varasm.h" |
09b42213 | 28 | #include "c-family/c-objc.h" |
29 | #include "tree-iterator.h" | |
30 | #include "gimplify.h" | |
31 | #include "builtins.h" | |
9c96033c | 32 | #include "tree-inline.h" |
6b71bdb4 | 33 | #include "ubsan.h" |
732905bb | 34 | #include "gimple-fold.h" |
c300fe28 | 35 | #include "timevar.h" |
09b42213 | 36 | |
37 | static bool verify_constant (tree, bool, bool *, bool *); | |
38 | #define VERIFY_CONSTANT(X) \ | |
39 | do { \ | |
f83e6885 | 40 | if (verify_constant ((X), ctx->quiet, non_constant_p, overflow_p)) \ |
09b42213 | 41 | return t; \ |
42 | } while (0) | |
43 | ||
44 | /* Returns true iff FUN is an instantiation of a constexpr function | |
45 | template or a defaulted constexpr function. */ | |
46 | ||
47 | bool | |
48 | is_instantiation_of_constexpr (tree fun) | |
49 | { | |
50 | return ((DECL_TEMPLOID_INSTANTIATION (fun) | |
51 | && DECL_DECLARED_CONSTEXPR_P (DECL_TI_TEMPLATE (fun))) | |
52 | || (DECL_DEFAULTED_FN (fun) | |
53 | && DECL_DECLARED_CONSTEXPR_P (fun))); | |
54 | } | |
55 | ||
56 | /* Return true if T is a literal type. */ | |
57 | ||
58 | bool | |
59 | literal_type_p (tree t) | |
60 | { | |
61 | if (SCALAR_TYPE_P (t) | |
76249021 | 62 | || VECTOR_TYPE_P (t) |
dd418b39 | 63 | || TREE_CODE (t) == REFERENCE_TYPE |
64 | || (VOID_TYPE_P (t) && cxx_dialect >= cxx14)) | |
09b42213 | 65 | return true; |
66 | if (CLASS_TYPE_P (t)) | |
67 | { | |
68 | t = complete_type (t); | |
69 | gcc_assert (COMPLETE_TYPE_P (t) || errorcount); | |
70 | return CLASSTYPE_LITERAL_P (t); | |
71 | } | |
72 | if (TREE_CODE (t) == ARRAY_TYPE) | |
73 | return literal_type_p (strip_array_types (t)); | |
74 | return false; | |
75 | } | |
76 | ||
77 | /* If DECL is a variable declared `constexpr', require its type | |
e89257db | 78 | be literal. Return error_mark_node if we give an error, the |
79 | DECL otherwise. */ | |
09b42213 | 80 | |
81 | tree | |
82 | ensure_literal_type_for_constexpr_object (tree decl) | |
83 | { | |
84 | tree type = TREE_TYPE (decl); | |
85 | if (VAR_P (decl) | |
86 | && (DECL_DECLARED_CONSTEXPR_P (decl) | |
87 | || var_in_constexpr_fn (decl)) | |
88 | && !processing_template_decl) | |
89 | { | |
90 | tree stype = strip_array_types (type); | |
91 | if (CLASS_TYPE_P (stype) && !COMPLETE_TYPE_P (complete_type (stype))) | |
92 | /* Don't complain here, we'll complain about incompleteness | |
93 | when we try to initialize the variable. */; | |
94 | else if (!literal_type_p (type)) | |
95 | { | |
96 | if (DECL_DECLARED_CONSTEXPR_P (decl)) | |
e45408ff | 97 | { |
5967b28b | 98 | error ("the type %qT of %<constexpr%> variable %qD " |
99 | "is not literal", type, decl); | |
e45408ff | 100 | explain_non_literal_class (type); |
e89257db | 101 | decl = error_mark_node; |
e45408ff | 102 | } |
09b42213 | 103 | else |
9c96033c | 104 | { |
b7e4a558 | 105 | if (!is_instantiation_of_constexpr (current_function_decl)) |
e45408ff | 106 | { |
107 | error ("variable %qD of non-literal type %qT in %<constexpr%> " | |
108 | "function", decl, type); | |
109 | explain_non_literal_class (type); | |
e89257db | 110 | decl = error_mark_node; |
e45408ff | 111 | } |
9c96033c | 112 | cp_function_chain->invalid_constexpr = true; |
113 | } | |
09b42213 | 114 | } |
fdafeeb7 | 115 | else if (DECL_DECLARED_CONSTEXPR_P (decl) |
116 | && variably_modified_type_p (type, NULL_TREE)) | |
117 | { | |
118 | error ("%<constexpr%> variable %qD has variably-modified type %qT", | |
119 | decl, type); | |
120 | decl = error_mark_node; | |
121 | } | |
09b42213 | 122 | } |
123 | return decl; | |
124 | } | |
125 | ||
126 | /* Representation of entries in the constexpr function definition table. */ | |
127 | ||
128 | struct GTY((for_user)) constexpr_fundef { | |
129 | tree decl; | |
130 | tree body; | |
131 | }; | |
132 | ||
b594087e | 133 | struct constexpr_fundef_hasher : ggc_ptr_hash<constexpr_fundef> |
09b42213 | 134 | { |
135 | static hashval_t hash (constexpr_fundef *); | |
136 | static bool equal (constexpr_fundef *, constexpr_fundef *); | |
137 | }; | |
138 | ||
139 | /* This table holds all constexpr function definitions seen in | |
140 | the current translation unit. */ | |
141 | ||
142 | static GTY (()) hash_table<constexpr_fundef_hasher> *constexpr_fundef_table; | |
143 | ||
144 | /* Utility function used for managing the constexpr function table. | |
145 | Return true if the entries pointed to by P and Q are for the | |
146 | same constexpr function. */ | |
147 | ||
148 | inline bool | |
149 | constexpr_fundef_hasher::equal (constexpr_fundef *lhs, constexpr_fundef *rhs) | |
150 | { | |
151 | return lhs->decl == rhs->decl; | |
152 | } | |
153 | ||
154 | /* Utility function used for managing the constexpr function table. | |
155 | Return a hash value for the entry pointed to by Q. */ | |
156 | ||
157 | inline hashval_t | |
158 | constexpr_fundef_hasher::hash (constexpr_fundef *fundef) | |
159 | { | |
160 | return DECL_UID (fundef->decl); | |
161 | } | |
162 | ||
163 | /* Return a previously saved definition of function FUN. */ | |
164 | ||
165 | static constexpr_fundef * | |
166 | retrieve_constexpr_fundef (tree fun) | |
167 | { | |
168 | constexpr_fundef fundef = { NULL, NULL }; | |
169 | if (constexpr_fundef_table == NULL) | |
170 | return NULL; | |
171 | ||
172 | fundef.decl = fun; | |
173 | return constexpr_fundef_table->find (&fundef); | |
174 | } | |
175 | ||
176 | /* Check whether the parameter and return types of FUN are valid for a | |
177 | constexpr function, and complain if COMPLAIN. */ | |
178 | ||
33603066 | 179 | bool |
09b42213 | 180 | is_valid_constexpr_fn (tree fun, bool complain) |
181 | { | |
182 | bool ret = true; | |
183 | ||
7896267d | 184 | if (DECL_INHERITED_CTOR (fun) |
09b42213 | 185 | && TREE_CODE (fun) == TEMPLATE_DECL) |
186 | { | |
187 | ret = false; | |
188 | if (complain) | |
5967b28b | 189 | error ("inherited constructor %qD is not %<constexpr%>", |
7896267d | 190 | DECL_INHERITED_CTOR (fun)); |
09b42213 | 191 | } |
192 | else | |
193 | { | |
194 | for (tree parm = FUNCTION_FIRST_USER_PARM (fun); | |
195 | parm != NULL_TREE; parm = TREE_CHAIN (parm)) | |
196 | if (!literal_type_p (TREE_TYPE (parm))) | |
197 | { | |
198 | ret = false; | |
199 | if (complain) | |
200 | { | |
5967b28b | 201 | error ("invalid type for parameter %d of %<constexpr%> " |
09b42213 | 202 | "function %q+#D", DECL_PARM_INDEX (parm), fun); |
203 | explain_non_literal_class (TREE_TYPE (parm)); | |
204 | } | |
205 | } | |
206 | } | |
207 | ||
672871ce | 208 | if (LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) && cxx_dialect < cxx17) |
209 | { | |
210 | ret = false; | |
211 | if (complain) | |
212 | inform (DECL_SOURCE_LOCATION (fun), | |
5967b28b | 213 | "lambdas are implicitly %<constexpr%> only in C++17 and later"); |
672871ce | 214 | } |
215 | else if (!DECL_CONSTRUCTOR_P (fun)) | |
09b42213 | 216 | { |
217 | tree rettype = TREE_TYPE (TREE_TYPE (fun)); | |
218 | if (!literal_type_p (rettype)) | |
219 | { | |
220 | ret = false; | |
221 | if (complain) | |
222 | { | |
5967b28b | 223 | error ("invalid return type %qT of %<constexpr%> function %q+D", |
09b42213 | 224 | rettype, fun); |
225 | explain_non_literal_class (rettype); | |
226 | } | |
227 | } | |
228 | ||
d66f34cf | 229 | /* C++14 DR 1684 removed this restriction. */ |
230 | if (cxx_dialect < cxx14 | |
231 | && DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
09b42213 | 232 | && !CLASSTYPE_LITERAL_P (DECL_CONTEXT (fun))) |
233 | { | |
234 | ret = false; | |
d66f34cf | 235 | if (complain |
236 | && pedwarn (DECL_SOURCE_LOCATION (fun), OPT_Wpedantic, | |
5967b28b | 237 | "enclosing class of %<constexpr%> non-static member " |
d66f34cf | 238 | "function %q+#D is not a literal type", fun)) |
239 | explain_non_literal_class (DECL_CONTEXT (fun)); | |
09b42213 | 240 | } |
241 | } | |
242 | else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun))) | |
243 | { | |
244 | ret = false; | |
245 | if (complain) | |
246 | error ("%q#T has virtual base classes", DECL_CONTEXT (fun)); | |
247 | } | |
248 | ||
249 | return ret; | |
250 | } | |
251 | ||
252 | /* Subroutine of build_data_member_initialization. MEMBER is a COMPONENT_REF | |
253 | for a member of an anonymous aggregate, INIT is the initializer for that | |
254 | member, and VEC_OUTER is the vector of constructor elements for the class | |
255 | whose constructor we are processing. Add the initializer to the vector | |
256 | and return true to indicate success. */ | |
257 | ||
258 | static bool | |
259 | build_anon_member_initialization (tree member, tree init, | |
260 | vec<constructor_elt, va_gc> **vec_outer) | |
261 | { | |
262 | /* MEMBER presents the relevant fields from the inside out, but we need | |
263 | to build up the initializer from the outside in so that we can reuse | |
264 | previously built CONSTRUCTORs if this is, say, the second field in an | |
265 | anonymous struct. So we use a vec as a stack. */ | |
266 | auto_vec<tree, 2> fields; | |
267 | do | |
268 | { | |
269 | fields.safe_push (TREE_OPERAND (member, 1)); | |
270 | member = TREE_OPERAND (member, 0); | |
271 | } | |
272 | while (ANON_AGGR_TYPE_P (TREE_TYPE (member)) | |
273 | && TREE_CODE (member) == COMPONENT_REF); | |
274 | ||
275 | /* VEC has the constructor elements vector for the context of FIELD. | |
276 | If FIELD is an anonymous aggregate, we will push inside it. */ | |
277 | vec<constructor_elt, va_gc> **vec = vec_outer; | |
278 | tree field; | |
279 | while (field = fields.pop(), | |
280 | ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
281 | { | |
282 | tree ctor; | |
283 | /* If there is already an outer constructor entry for the anonymous | |
284 | aggregate FIELD, use it; otherwise, insert one. */ | |
285 | if (vec_safe_is_empty (*vec) | |
286 | || (*vec)->last().index != field) | |
287 | { | |
288 | ctor = build_constructor (TREE_TYPE (field), NULL); | |
289 | CONSTRUCTOR_APPEND_ELT (*vec, field, ctor); | |
290 | } | |
291 | else | |
292 | ctor = (*vec)->last().value; | |
293 | vec = &CONSTRUCTOR_ELTS (ctor); | |
294 | } | |
295 | ||
296 | /* Now we're at the innermost field, the one that isn't an anonymous | |
297 | aggregate. Add its initializer to the CONSTRUCTOR and we're done. */ | |
298 | gcc_assert (fields.is_empty()); | |
299 | CONSTRUCTOR_APPEND_ELT (*vec, field, init); | |
300 | ||
301 | return true; | |
302 | } | |
303 | ||
304 | /* Subroutine of build_constexpr_constructor_member_initializers. | |
305 | The expression tree T represents a data member initialization | |
306 | in a (constexpr) constructor definition. Build a pairing of | |
307 | the data member with its initializer, and prepend that pair | |
308 | to the existing initialization pair INITS. */ | |
309 | ||
310 | static bool | |
311 | build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec) | |
312 | { | |
313 | tree member, init; | |
314 | if (TREE_CODE (t) == CLEANUP_POINT_EXPR) | |
315 | t = TREE_OPERAND (t, 0); | |
316 | if (TREE_CODE (t) == EXPR_STMT) | |
317 | t = TREE_OPERAND (t, 0); | |
318 | if (t == error_mark_node) | |
319 | return false; | |
320 | if (TREE_CODE (t) == STATEMENT_LIST) | |
321 | { | |
322 | tree_stmt_iterator i; | |
323 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
324 | { | |
325 | if (! build_data_member_initialization (tsi_stmt (i), vec)) | |
326 | return false; | |
327 | } | |
328 | return true; | |
329 | } | |
330 | if (TREE_CODE (t) == CLEANUP_STMT) | |
331 | { | |
332 | /* We can't see a CLEANUP_STMT in a constructor for a literal class, | |
333 | but we can in a constexpr constructor for a non-literal class. Just | |
334 | ignore it; either all the initialization will be constant, in which | |
335 | case the cleanup can't run, or it can't be constexpr. | |
336 | Still recurse into CLEANUP_BODY. */ | |
337 | return build_data_member_initialization (CLEANUP_BODY (t), vec); | |
338 | } | |
339 | if (TREE_CODE (t) == CONVERT_EXPR) | |
340 | t = TREE_OPERAND (t, 0); | |
341 | if (TREE_CODE (t) == INIT_EXPR | |
9c96033c | 342 | /* vptr initialization shows up as a MODIFY_EXPR. In C++14 we only |
343 | use what this function builds for cx_check_missing_mem_inits, and | |
344 | assignment in the ctor body doesn't count. */ | |
345 | || (cxx_dialect < cxx14 && TREE_CODE (t) == MODIFY_EXPR)) | |
09b42213 | 346 | { |
347 | member = TREE_OPERAND (t, 0); | |
348 | init = break_out_target_exprs (TREE_OPERAND (t, 1)); | |
349 | } | |
350 | else if (TREE_CODE (t) == CALL_EXPR) | |
351 | { | |
9c96033c | 352 | tree fn = get_callee_fndecl (t); |
353 | if (!fn || !DECL_CONSTRUCTOR_P (fn)) | |
354 | /* We're only interested in calls to subobject constructors. */ | |
355 | return true; | |
09b42213 | 356 | member = CALL_EXPR_ARG (t, 0); |
357 | /* We don't use build_cplus_new here because it complains about | |
358 | abstract bases. Leaving the call unwrapped means that it has the | |
359 | wrong type, but cxx_eval_constant_expression doesn't care. */ | |
360 | init = break_out_target_exprs (t); | |
361 | } | |
362 | else if (TREE_CODE (t) == BIND_EXPR) | |
363 | return build_data_member_initialization (BIND_EXPR_BODY (t), vec); | |
09b42213 | 364 | else |
9c96033c | 365 | /* Don't add anything else to the CONSTRUCTOR. */ |
366 | return true; | |
09b42213 | 367 | if (INDIRECT_REF_P (member)) |
368 | member = TREE_OPERAND (member, 0); | |
369 | if (TREE_CODE (member) == NOP_EXPR) | |
370 | { | |
371 | tree op = member; | |
372 | STRIP_NOPS (op); | |
373 | if (TREE_CODE (op) == ADDR_EXPR) | |
374 | { | |
375 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
376 | (TREE_TYPE (TREE_TYPE (op)), | |
377 | TREE_TYPE (TREE_TYPE (member)))); | |
378 | /* Initializing a cv-qualified member; we need to look through | |
379 | the const_cast. */ | |
380 | member = op; | |
381 | } | |
382 | else if (op == current_class_ptr | |
383 | && (same_type_ignoring_top_level_qualifiers_p | |
384 | (TREE_TYPE (TREE_TYPE (member)), | |
385 | current_class_type))) | |
386 | /* Delegating constructor. */ | |
387 | member = op; | |
388 | else | |
389 | { | |
390 | /* This is an initializer for an empty base; keep it for now so | |
391 | we can check it in cxx_eval_bare_aggregate. */ | |
392 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (member)))); | |
393 | } | |
394 | } | |
395 | if (TREE_CODE (member) == ADDR_EXPR) | |
396 | member = TREE_OPERAND (member, 0); | |
397 | if (TREE_CODE (member) == COMPONENT_REF) | |
398 | { | |
399 | tree aggr = TREE_OPERAND (member, 0); | |
4952bc85 | 400 | if (TREE_CODE (aggr) == VAR_DECL) |
401 | /* Initializing a local variable, don't add anything. */ | |
402 | return true; | |
09b42213 | 403 | if (TREE_CODE (aggr) != COMPONENT_REF) |
404 | /* Normal member initialization. */ | |
405 | member = TREE_OPERAND (member, 1); | |
406 | else if (ANON_AGGR_TYPE_P (TREE_TYPE (aggr))) | |
407 | /* Initializing a member of an anonymous union. */ | |
408 | return build_anon_member_initialization (member, init, vec); | |
409 | else | |
410 | /* We're initializing a vtable pointer in a base. Leave it as | |
411 | COMPONENT_REF so we remember the path to get to the vfield. */ | |
412 | gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node); | |
413 | } | |
414 | ||
c678e23e | 415 | /* Value-initialization can produce multiple initializers for the |
416 | same field; use the last one. */ | |
417 | if (!vec_safe_is_empty (*vec) && (*vec)->last().index == member) | |
418 | (*vec)->last().value = init; | |
419 | else | |
420 | CONSTRUCTOR_APPEND_ELT (*vec, member, init); | |
09b42213 | 421 | return true; |
422 | } | |
423 | ||
424 | /* Subroutine of check_constexpr_ctor_body_1 and constexpr_fn_retval. | |
425 | In C++11 mode checks that the TYPE_DECLs in the BIND_EXPR_VARS of a | |
426 | BIND_EXPR conform to 7.1.5/3/4 on typedef and alias declarations. */ | |
427 | ||
428 | static bool | |
429 | check_constexpr_bind_expr_vars (tree t) | |
430 | { | |
431 | gcc_assert (TREE_CODE (t) == BIND_EXPR); | |
432 | ||
09b42213 | 433 | for (tree var = BIND_EXPR_VARS (t); var; var = DECL_CHAIN (var)) |
434 | if (TREE_CODE (var) == TYPE_DECL | |
04103c39 | 435 | && DECL_IMPLICIT_TYPEDEF_P (var) |
436 | && !LAMBDA_TYPE_P (TREE_TYPE (var))) | |
09b42213 | 437 | return false; |
438 | return true; | |
439 | } | |
440 | ||
441 | /* Subroutine of check_constexpr_ctor_body. */ | |
442 | ||
443 | static bool | |
444 | check_constexpr_ctor_body_1 (tree last, tree list) | |
445 | { | |
446 | switch (TREE_CODE (list)) | |
447 | { | |
448 | case DECL_EXPR: | |
810702a2 | 449 | if (TREE_CODE (DECL_EXPR_DECL (list)) == USING_DECL |
450 | || TREE_CODE (DECL_EXPR_DECL (list)) == TYPE_DECL) | |
09b42213 | 451 | return true; |
09b42213 | 452 | return false; |
453 | ||
454 | case CLEANUP_POINT_EXPR: | |
455 | return check_constexpr_ctor_body (last, TREE_OPERAND (list, 0), | |
456 | /*complain=*/false); | |
457 | ||
458 | case BIND_EXPR: | |
459 | if (!check_constexpr_bind_expr_vars (list) | |
460 | || !check_constexpr_ctor_body (last, BIND_EXPR_BODY (list), | |
461 | /*complain=*/false)) | |
462 | return false; | |
463 | return true; | |
464 | ||
465 | case USING_STMT: | |
466 | case STATIC_ASSERT: | |
90567983 | 467 | case DEBUG_BEGIN_STMT: |
09b42213 | 468 | return true; |
469 | ||
470 | default: | |
471 | return false; | |
472 | } | |
473 | } | |
474 | ||
475 | /* Make sure that there are no statements after LAST in the constructor | |
476 | body represented by LIST. */ | |
477 | ||
478 | bool | |
479 | check_constexpr_ctor_body (tree last, tree list, bool complain) | |
480 | { | |
9c96033c | 481 | /* C++14 doesn't require a constexpr ctor to have an empty body. */ |
482 | if (cxx_dialect >= cxx14) | |
483 | return true; | |
484 | ||
09b42213 | 485 | bool ok = true; |
486 | if (TREE_CODE (list) == STATEMENT_LIST) | |
487 | { | |
488 | tree_stmt_iterator i = tsi_last (list); | |
489 | for (; !tsi_end_p (i); tsi_prev (&i)) | |
490 | { | |
491 | tree t = tsi_stmt (i); | |
492 | if (t == last) | |
493 | break; | |
494 | if (!check_constexpr_ctor_body_1 (last, t)) | |
495 | { | |
496 | ok = false; | |
497 | break; | |
498 | } | |
499 | } | |
500 | } | |
501 | else if (list != last | |
502 | && !check_constexpr_ctor_body_1 (last, list)) | |
503 | ok = false; | |
504 | if (!ok) | |
505 | { | |
506 | if (complain) | |
5967b28b | 507 | error ("%<constexpr%> constructor does not have empty body"); |
09b42213 | 508 | DECL_DECLARED_CONSTEXPR_P (current_function_decl) = false; |
509 | } | |
510 | return ok; | |
511 | } | |
512 | ||
513 | /* V is a vector of constructor elements built up for the base and member | |
514 | initializers of a constructor for TYPE. They need to be in increasing | |
515 | offset order, which they might not be yet if TYPE has a primary base | |
516 | which is not first in the base-clause or a vptr and at least one base | |
517 | all of which are non-primary. */ | |
518 | ||
519 | static vec<constructor_elt, va_gc> * | |
520 | sort_constexpr_mem_initializers (tree type, vec<constructor_elt, va_gc> *v) | |
521 | { | |
522 | tree pri = CLASSTYPE_PRIMARY_BINFO (type); | |
523 | tree field_type; | |
524 | unsigned i; | |
525 | constructor_elt *ce; | |
526 | ||
527 | if (pri) | |
528 | field_type = BINFO_TYPE (pri); | |
529 | else if (TYPE_CONTAINS_VPTR_P (type)) | |
530 | field_type = vtbl_ptr_type_node; | |
531 | else | |
532 | return v; | |
533 | ||
534 | /* Find the element for the primary base or vptr and move it to the | |
535 | beginning of the vec. */ | |
536 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
537 | if (TREE_TYPE (ce->index) == field_type) | |
538 | break; | |
539 | ||
540 | if (i > 0 && i < vec_safe_length (v)) | |
541 | { | |
542 | vec<constructor_elt, va_gc> &vref = *v; | |
543 | constructor_elt elt = vref[i]; | |
544 | for (; i > 0; --i) | |
545 | vref[i] = vref[i-1]; | |
546 | vref[0] = elt; | |
547 | } | |
548 | ||
549 | return v; | |
550 | } | |
551 | ||
552 | /* Build compile-time evalable representations of member-initializer list | |
553 | for a constexpr constructor. */ | |
554 | ||
555 | static tree | |
556 | build_constexpr_constructor_member_initializers (tree type, tree body) | |
557 | { | |
558 | vec<constructor_elt, va_gc> *vec = NULL; | |
559 | bool ok = true; | |
816919e1 | 560 | while (true) |
561 | switch (TREE_CODE (body)) | |
562 | { | |
563 | case MUST_NOT_THROW_EXPR: | |
564 | case EH_SPEC_BLOCK: | |
565 | body = TREE_OPERAND (body, 0); | |
566 | break; | |
567 | ||
568 | case STATEMENT_LIST: | |
569 | for (tree_stmt_iterator i = tsi_start (body); | |
570 | !tsi_end_p (i); tsi_next (&i)) | |
571 | { | |
572 | body = tsi_stmt (i); | |
573 | if (TREE_CODE (body) == BIND_EXPR) | |
574 | break; | |
575 | } | |
576 | break; | |
577 | ||
578 | case BIND_EXPR: | |
579 | body = BIND_EXPR_BODY (body); | |
580 | goto found; | |
581 | ||
582 | default: | |
583 | gcc_unreachable (); | |
8a36d0ec | 584 | } |
816919e1 | 585 | found: |
09b42213 | 586 | if (TREE_CODE (body) == CLEANUP_POINT_EXPR) |
587 | { | |
588 | body = TREE_OPERAND (body, 0); | |
589 | if (TREE_CODE (body) == EXPR_STMT) | |
590 | body = TREE_OPERAND (body, 0); | |
591 | if (TREE_CODE (body) == INIT_EXPR | |
592 | && (same_type_ignoring_top_level_qualifiers_p | |
593 | (TREE_TYPE (TREE_OPERAND (body, 0)), | |
594 | current_class_type))) | |
595 | { | |
596 | /* Trivial copy. */ | |
597 | return TREE_OPERAND (body, 1); | |
598 | } | |
599 | ok = build_data_member_initialization (body, &vec); | |
600 | } | |
601 | else if (TREE_CODE (body) == STATEMENT_LIST) | |
602 | { | |
603 | tree_stmt_iterator i; | |
604 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
605 | { | |
606 | ok = build_data_member_initialization (tsi_stmt (i), &vec); | |
607 | if (!ok) | |
608 | break; | |
609 | } | |
610 | } | |
611 | else if (TREE_CODE (body) == TRY_BLOCK) | |
612 | { | |
613 | error ("body of %<constexpr%> constructor cannot be " | |
614 | "a function-try-block"); | |
615 | return error_mark_node; | |
616 | } | |
617 | else if (EXPR_P (body)) | |
618 | ok = build_data_member_initialization (body, &vec); | |
619 | else | |
620 | gcc_assert (errorcount > 0); | |
621 | if (ok) | |
622 | { | |
623 | if (vec_safe_length (vec) > 0) | |
624 | { | |
625 | /* In a delegating constructor, return the target. */ | |
626 | constructor_elt *ce = &(*vec)[0]; | |
627 | if (ce->index == current_class_ptr) | |
628 | { | |
629 | body = ce->value; | |
630 | vec_free (vec); | |
631 | return body; | |
632 | } | |
633 | } | |
634 | vec = sort_constexpr_mem_initializers (type, vec); | |
635 | return build_constructor (type, vec); | |
636 | } | |
637 | else | |
638 | return error_mark_node; | |
639 | } | |
640 | ||
2fb20ba2 | 641 | /* We have an expression tree T that represents a call, either CALL_EXPR |
642 | or AGGR_INIT_EXPR. If the call is lexically to a named function, | |
643 | retrun the _DECL for that function. */ | |
644 | ||
645 | static tree | |
646 | get_function_named_in_call (tree t) | |
647 | { | |
648 | tree fun = cp_get_callee (t); | |
649 | if (fun && TREE_CODE (fun) == ADDR_EXPR | |
650 | && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL) | |
651 | fun = TREE_OPERAND (fun, 0); | |
652 | return fun; | |
653 | } | |
654 | ||
09b42213 | 655 | /* Subroutine of register_constexpr_fundef. BODY is the body of a function |
656 | declared to be constexpr, or a sub-statement thereof. Returns the | |
657 | return value if suitable, error_mark_node for a statement not allowed in | |
658 | a constexpr function, or NULL_TREE if no return value was found. */ | |
659 | ||
c49bd35e | 660 | tree |
09b42213 | 661 | constexpr_fn_retval (tree body) |
662 | { | |
663 | switch (TREE_CODE (body)) | |
664 | { | |
665 | case STATEMENT_LIST: | |
666 | { | |
667 | tree_stmt_iterator i; | |
668 | tree expr = NULL_TREE; | |
669 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
670 | { | |
671 | tree s = constexpr_fn_retval (tsi_stmt (i)); | |
672 | if (s == error_mark_node) | |
673 | return error_mark_node; | |
674 | else if (s == NULL_TREE) | |
675 | /* Keep iterating. */; | |
676 | else if (expr) | |
677 | /* Multiple return statements. */ | |
678 | return error_mark_node; | |
679 | else | |
680 | expr = s; | |
681 | } | |
682 | return expr; | |
683 | } | |
684 | ||
685 | case RETURN_EXPR: | |
686 | return break_out_target_exprs (TREE_OPERAND (body, 0)); | |
687 | ||
688 | case DECL_EXPR: | |
394aed6a | 689 | { |
690 | tree decl = DECL_EXPR_DECL (body); | |
691 | if (TREE_CODE (decl) == USING_DECL | |
692 | /* Accept __func__, __FUNCTION__, and __PRETTY_FUNCTION__. */ | |
693 | || DECL_ARTIFICIAL (decl)) | |
694 | return NULL_TREE; | |
695 | return error_mark_node; | |
696 | } | |
09b42213 | 697 | |
698 | case CLEANUP_POINT_EXPR: | |
699 | return constexpr_fn_retval (TREE_OPERAND (body, 0)); | |
700 | ||
701 | case BIND_EXPR: | |
702 | if (!check_constexpr_bind_expr_vars (body)) | |
703 | return error_mark_node; | |
704 | return constexpr_fn_retval (BIND_EXPR_BODY (body)); | |
705 | ||
706 | case USING_STMT: | |
90567983 | 707 | case DEBUG_BEGIN_STMT: |
09b42213 | 708 | return NULL_TREE; |
709 | ||
2fb20ba2 | 710 | case CALL_EXPR: |
711 | { | |
712 | tree fun = get_function_named_in_call (body); | |
713 | if (fun != NULL_TREE | |
714 | && DECL_FUNCTION_CODE (fun) == BUILT_IN_UNREACHABLE) | |
715 | return NULL_TREE; | |
716 | } | |
717 | /* Fallthru. */ | |
718 | ||
09b42213 | 719 | default: |
720 | return error_mark_node; | |
721 | } | |
722 | } | |
723 | ||
724 | /* Subroutine of register_constexpr_fundef. BODY is the DECL_SAVED_TREE of | |
725 | FUN; do the necessary transformations to turn it into a single expression | |
726 | that we can store in the hash table. */ | |
727 | ||
728 | static tree | |
729 | massage_constexpr_body (tree fun, tree body) | |
730 | { | |
731 | if (DECL_CONSTRUCTOR_P (fun)) | |
732 | body = build_constexpr_constructor_member_initializers | |
733 | (DECL_CONTEXT (fun), body); | |
9c96033c | 734 | else if (cxx_dialect < cxx14) |
09b42213 | 735 | { |
736 | if (TREE_CODE (body) == EH_SPEC_BLOCK) | |
737 | body = EH_SPEC_STMTS (body); | |
738 | if (TREE_CODE (body) == MUST_NOT_THROW_EXPR) | |
739 | body = TREE_OPERAND (body, 0); | |
740 | body = constexpr_fn_retval (body); | |
741 | } | |
742 | return body; | |
743 | } | |
744 | ||
2f4cab3c | 745 | /* CTYPE is a type constructed from BODY. Return true if some |
746 | bases/fields are uninitialized, and complain if COMPLAIN. */ | |
09b42213 | 747 | |
748 | static bool | |
2f4cab3c | 749 | cx_check_missing_mem_inits (tree ctype, tree body, bool complain) |
09b42213 | 750 | { |
2f4cab3c | 751 | unsigned nelts = 0; |
752 | ||
753 | if (body) | |
754 | { | |
755 | if (TREE_CODE (body) != CONSTRUCTOR) | |
756 | return false; | |
757 | nelts = CONSTRUCTOR_NELTS (body); | |
758 | } | |
759 | tree field = TYPE_FIELDS (ctype); | |
09b42213 | 760 | |
761 | if (TREE_CODE (ctype) == UNION_TYPE) | |
762 | { | |
763 | if (nelts == 0 && next_initializable_field (field)) | |
764 | { | |
765 | if (complain) | |
766 | error ("%<constexpr%> constructor for union %qT must " | |
767 | "initialize exactly one non-static data member", ctype); | |
768 | return true; | |
769 | } | |
770 | return false; | |
771 | } | |
772 | ||
2f4cab3c | 773 | /* Iterate over the CONSTRUCTOR, checking any missing fields don't |
774 | need an explicit initialization. */ | |
775 | bool bad = false; | |
776 | for (unsigned i = 0; i <= nelts; ++i) | |
09b42213 | 777 | { |
2f4cab3c | 778 | tree index = NULL_TREE; |
779 | if (i < nelts) | |
09b42213 | 780 | { |
781 | index = CONSTRUCTOR_ELT (body, i)->index; | |
782 | /* Skip base and vtable inits. */ | |
783 | if (TREE_CODE (index) != FIELD_DECL | |
784 | || DECL_ARTIFICIAL (index)) | |
785 | continue; | |
786 | } | |
2f4cab3c | 787 | |
09b42213 | 788 | for (; field != index; field = DECL_CHAIN (field)) |
789 | { | |
790 | tree ftype; | |
2f4cab3c | 791 | if (TREE_CODE (field) != FIELD_DECL) |
792 | continue; | |
3cde3c29 | 793 | if (DECL_UNNAMED_BIT_FIELD (field)) |
09b42213 | 794 | continue; |
2f4cab3c | 795 | if (DECL_ARTIFICIAL (field)) |
796 | continue; | |
797 | if (ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
798 | { | |
799 | /* Recurse to check the anonummous aggregate member. */ | |
800 | bad |= cx_check_missing_mem_inits | |
801 | (TREE_TYPE (field), NULL_TREE, complain); | |
802 | if (bad && !complain) | |
803 | return true; | |
804 | continue; | |
805 | } | |
09b42213 | 806 | ftype = strip_array_types (TREE_TYPE (field)); |
807 | if (type_has_constexpr_default_constructor (ftype)) | |
808 | { | |
809 | /* It's OK to skip a member with a trivial constexpr ctor. | |
810 | A constexpr ctor that isn't trivial should have been | |
811 | added in by now. */ | |
812 | gcc_checking_assert (!TYPE_HAS_COMPLEX_DFLT (ftype) | |
813 | || errorcount != 0); | |
814 | continue; | |
815 | } | |
816 | if (!complain) | |
817 | return true; | |
859e2c29 | 818 | error ("member %qD must be initialized by mem-initializer " |
819 | "in %<constexpr%> constructor", field); | |
820 | inform (DECL_SOURCE_LOCATION (field), "declared here"); | |
09b42213 | 821 | bad = true; |
822 | } | |
823 | if (field == NULL_TREE) | |
824 | break; | |
2f4cab3c | 825 | |
826 | if (ANON_AGGR_TYPE_P (TREE_TYPE (index))) | |
827 | { | |
828 | /* Check the anonymous aggregate initializer is valid. */ | |
829 | bad |= cx_check_missing_mem_inits | |
830 | (TREE_TYPE (index), CONSTRUCTOR_ELT (body, i)->value, complain); | |
831 | if (bad && !complain) | |
832 | return true; | |
833 | } | |
09b42213 | 834 | field = DECL_CHAIN (field); |
835 | } | |
836 | ||
837 | return bad; | |
838 | } | |
839 | ||
840 | /* We are processing the definition of the constexpr function FUN. | |
841 | Check that its BODY fulfills the propriate requirements and | |
842 | enter it in the constexpr function definition table. | |
843 | For constructor BODY is actually the TREE_LIST of the | |
844 | member-initializer list. */ | |
845 | ||
846 | tree | |
847 | register_constexpr_fundef (tree fun, tree body) | |
848 | { | |
849 | constexpr_fundef entry; | |
850 | constexpr_fundef **slot; | |
851 | ||
852 | if (!is_valid_constexpr_fn (fun, !DECL_GENERATED_P (fun))) | |
853 | return NULL; | |
854 | ||
6a385150 | 855 | tree massaged = massage_constexpr_body (fun, body); |
856 | if (massaged == NULL_TREE || massaged == error_mark_node) | |
09b42213 | 857 | { |
858 | if (!DECL_CONSTRUCTOR_P (fun)) | |
5967b28b | 859 | error ("body of %<constexpr%> function %qD not a return-statement", |
860 | fun); | |
09b42213 | 861 | return NULL; |
862 | } | |
863 | ||
6a385150 | 864 | if (!potential_rvalue_constant_expression (massaged)) |
09b42213 | 865 | { |
866 | if (!DECL_GENERATED_P (fun)) | |
6a385150 | 867 | require_potential_rvalue_constant_expression (massaged); |
09b42213 | 868 | return NULL; |
869 | } | |
870 | ||
871 | if (DECL_CONSTRUCTOR_P (fun) | |
2f4cab3c | 872 | && cx_check_missing_mem_inits (DECL_CONTEXT (fun), |
873 | massaged, !DECL_GENERATED_P (fun))) | |
09b42213 | 874 | return NULL; |
875 | ||
876 | /* Create the constexpr function table if necessary. */ | |
877 | if (constexpr_fundef_table == NULL) | |
878 | constexpr_fundef_table | |
879 | = hash_table<constexpr_fundef_hasher>::create_ggc (101); | |
880 | ||
881 | entry.decl = fun; | |
882 | entry.body = body; | |
883 | slot = constexpr_fundef_table->find_slot (&entry, INSERT); | |
884 | ||
885 | gcc_assert (*slot == NULL); | |
886 | *slot = ggc_alloc<constexpr_fundef> (); | |
887 | **slot = entry; | |
888 | ||
889 | return fun; | |
890 | } | |
891 | ||
892 | /* FUN is a non-constexpr function called in a context that requires a | |
893 | constant expression. If it comes from a constexpr template, explain why | |
894 | the instantiation isn't constexpr. */ | |
895 | ||
896 | void | |
897 | explain_invalid_constexpr_fn (tree fun) | |
898 | { | |
899 | static hash_set<tree> *diagnosed; | |
900 | tree body; | |
901 | location_t save_loc; | |
33603066 | 902 | /* Only diagnose defaulted functions, lambdas, or instantiations. */ |
09b42213 | 903 | if (!DECL_DEFAULTED_FN (fun) |
33603066 | 904 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) |
09b42213 | 905 | && !is_instantiation_of_constexpr (fun)) |
906 | return; | |
907 | if (diagnosed == NULL) | |
908 | diagnosed = new hash_set<tree>; | |
909 | if (diagnosed->add (fun)) | |
910 | /* Already explained. */ | |
911 | return; | |
912 | ||
913 | save_loc = input_location; | |
33603066 | 914 | if (!lambda_static_thunk_p (fun)) |
915 | { | |
916 | /* Diagnostics should completely ignore the static thunk, so leave | |
917 | input_location set to our caller's location. */ | |
918 | input_location = DECL_SOURCE_LOCATION (fun); | |
919 | inform (input_location, | |
5967b28b | 920 | "%qD is not usable as a %<constexpr%> function because:", fun); |
33603066 | 921 | } |
09b42213 | 922 | /* First check the declaration. */ |
923 | if (is_valid_constexpr_fn (fun, true)) | |
924 | { | |
925 | /* Then if it's OK, the body. */ | |
33603066 | 926 | if (!DECL_DECLARED_CONSTEXPR_P (fun) |
927 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun))) | |
09b42213 | 928 | explain_implicit_non_constexpr (fun); |
929 | else | |
930 | { | |
931 | body = massage_constexpr_body (fun, DECL_SAVED_TREE (fun)); | |
932 | require_potential_rvalue_constant_expression (body); | |
933 | if (DECL_CONSTRUCTOR_P (fun)) | |
2f4cab3c | 934 | cx_check_missing_mem_inits (DECL_CONTEXT (fun), body, true); |
09b42213 | 935 | } |
936 | } | |
937 | input_location = save_loc; | |
938 | } | |
939 | ||
940 | /* Objects of this type represent calls to constexpr functions | |
941 | along with the bindings of parameters to their arguments, for | |
942 | the purpose of compile time evaluation. */ | |
943 | ||
944 | struct GTY((for_user)) constexpr_call { | |
945 | /* Description of the constexpr function definition. */ | |
946 | constexpr_fundef *fundef; | |
947 | /* Parameter bindings environment. A TREE_LIST where each TREE_PURPOSE | |
948 | is a parameter _DECL and the TREE_VALUE is the value of the parameter. | |
949 | Note: This arrangement is made to accommodate the use of | |
950 | iterative_hash_template_arg (see pt.c). If you change this | |
951 | representation, also change the hash calculation in | |
952 | cxx_eval_call_expression. */ | |
953 | tree bindings; | |
954 | /* Result of the call. | |
955 | NULL means the call is being evaluated. | |
956 | error_mark_node means that the evaluation was erroneous; | |
957 | otherwise, the actuall value of the call. */ | |
958 | tree result; | |
959 | /* The hash of this call; we remember it here to avoid having to | |
960 | recalculate it when expanding the hash table. */ | |
961 | hashval_t hash; | |
962 | }; | |
963 | ||
b594087e | 964 | struct constexpr_call_hasher : ggc_ptr_hash<constexpr_call> |
09b42213 | 965 | { |
966 | static hashval_t hash (constexpr_call *); | |
967 | static bool equal (constexpr_call *, constexpr_call *); | |
cf72f34d | 968 | }; |
969 | ||
2a2770c6 | 970 | enum constexpr_switch_state { |
971 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
972 | and default: label for that switch has not been seen yet. */ | |
973 | css_default_not_seen, | |
974 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
975 | and default: label for that switch has been seen already. */ | |
976 | css_default_seen, | |
977 | /* Used when processing a switch for the second time by | |
978 | cxx_eval_switch_expr, where default: label should match. */ | |
979 | css_default_processing | |
980 | }; | |
981 | ||
cf72f34d | 982 | /* The constexpr expansion context. CALL is the current function |
983 | expansion, CTOR is the current aggregate initializer, OBJECT is the | |
984 | object being initialized by CTOR, either a VAR_DECL or a _REF. VALUES | |
985 | is a map of values of variables initialized within the expression. */ | |
986 | ||
987 | struct constexpr_ctx { | |
f9885b8a | 988 | /* The innermost call we're evaluating. */ |
cf72f34d | 989 | constexpr_call *call; |
f9885b8a | 990 | /* Values for any temporaries or local variables within the |
991 | constant-expression. */ | |
cf72f34d | 992 | hash_map<tree,tree> *values; |
2631cb67 | 993 | /* SAVE_EXPRs that we've seen within the current LOOP_EXPR. NULL if we |
994 | aren't inside a loop. */ | |
995 | hash_set<tree> *save_exprs; | |
f9885b8a | 996 | /* The CONSTRUCTOR we're currently building up for an aggregate |
997 | initializer. */ | |
cf72f34d | 998 | tree ctor; |
f9885b8a | 999 | /* The object we're building the CONSTRUCTOR for. */ |
cf72f34d | 1000 | tree object; |
2a2770c6 | 1001 | /* If inside SWITCH_EXPR. */ |
1002 | constexpr_switch_state *css_state; | |
f9885b8a | 1003 | /* Whether we should error on a non-constant expression or fail quietly. */ |
f83e6885 | 1004 | bool quiet; |
f9885b8a | 1005 | /* Whether we are strictly conforming to constant expression rules or |
1006 | trying harder to get a constant value. */ | |
2055d27a | 1007 | bool strict; |
cf72f34d | 1008 | }; |
09b42213 | 1009 | |
1010 | /* A table of all constexpr calls that have been evaluated by the | |
1011 | compiler in this translation unit. */ | |
1012 | ||
a050099a | 1013 | static GTY (()) hash_table<constexpr_call_hasher> *constexpr_call_table; |
09b42213 | 1014 | |
cf72f34d | 1015 | static tree cxx_eval_constant_expression (const constexpr_ctx *, tree, |
b2a43197 | 1016 | bool, bool *, bool *, tree * = NULL); |
09b42213 | 1017 | |
1018 | /* Compute a hash value for a constexpr call representation. */ | |
1019 | ||
1020 | inline hashval_t | |
1021 | constexpr_call_hasher::hash (constexpr_call *info) | |
1022 | { | |
1023 | return info->hash; | |
1024 | } | |
1025 | ||
1026 | /* Return true if the objects pointed to by P and Q represent calls | |
1027 | to the same constexpr function with the same arguments. | |
1028 | Otherwise, return false. */ | |
1029 | ||
1030 | bool | |
1031 | constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs) | |
1032 | { | |
1033 | tree lhs_bindings; | |
1034 | tree rhs_bindings; | |
1035 | if (lhs == rhs) | |
c751e2cd | 1036 | return true; |
1037 | if (lhs->hash != rhs->hash) | |
1038 | return false; | |
09b42213 | 1039 | if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef)) |
c751e2cd | 1040 | return false; |
09b42213 | 1041 | lhs_bindings = lhs->bindings; |
1042 | rhs_bindings = rhs->bindings; | |
1043 | while (lhs_bindings != NULL && rhs_bindings != NULL) | |
1044 | { | |
1045 | tree lhs_arg = TREE_VALUE (lhs_bindings); | |
1046 | tree rhs_arg = TREE_VALUE (rhs_bindings); | |
1047 | gcc_assert (TREE_TYPE (lhs_arg) == TREE_TYPE (rhs_arg)); | |
1048 | if (!cp_tree_equal (lhs_arg, rhs_arg)) | |
c751e2cd | 1049 | return false; |
09b42213 | 1050 | lhs_bindings = TREE_CHAIN (lhs_bindings); |
1051 | rhs_bindings = TREE_CHAIN (rhs_bindings); | |
1052 | } | |
1053 | return lhs_bindings == rhs_bindings; | |
1054 | } | |
1055 | ||
1056 | /* Initialize the constexpr call table, if needed. */ | |
1057 | ||
1058 | static void | |
1059 | maybe_initialize_constexpr_call_table (void) | |
1060 | { | |
1061 | if (constexpr_call_table == NULL) | |
1062 | constexpr_call_table = hash_table<constexpr_call_hasher>::create_ggc (101); | |
1063 | } | |
1064 | ||
4f7ebe46 | 1065 | /* During constexpr CALL_EXPR evaluation, to avoid issues with sharing when |
1066 | a function happens to get called recursively, we unshare the callee | |
1067 | function's body and evaluate this unshared copy instead of evaluating the | |
1068 | original body. | |
1069 | ||
1070 | FUNDEF_COPIES_TABLE is a per-function freelist of these unshared function | |
1071 | copies. The underlying data structure of FUNDEF_COPIES_TABLE is a hash_map | |
a050099a | 1072 | that's keyed off of the original FUNCTION_DECL and whose value is a |
1073 | TREE_LIST of this function's unused copies awaiting reuse. | |
4f7ebe46 | 1074 | |
a050099a | 1075 | This is not GC-deletable to avoid GC affecting UID generation. */ |
4f7ebe46 | 1076 | |
a050099a | 1077 | static GTY(()) hash_map<tree, tree> *fundef_copies_table; |
4f7ebe46 | 1078 | |
1079 | /* Initialize FUNDEF_COPIES_TABLE if it's not initialized. */ | |
1080 | ||
1081 | static void | |
1082 | maybe_initialize_fundef_copies_table () | |
1083 | { | |
a050099a | 1084 | if (fundef_copies_table == NULL) |
1085 | fundef_copies_table = hash_map<tree,tree>::create_ggc (101); | |
4f7ebe46 | 1086 | } |
1087 | ||
1088 | /* Reuse a copy or create a new unshared copy of the function FUN. | |
886d5463 | 1089 | Return this copy. We use a TREE_LIST whose PURPOSE is body, VALUE |
1090 | is parms, TYPE is result. */ | |
4f7ebe46 | 1091 | |
a050099a | 1092 | static tree |
4f7ebe46 | 1093 | get_fundef_copy (tree fun) |
1094 | { | |
1095 | maybe_initialize_fundef_copies_table (); | |
1096 | ||
a050099a | 1097 | tree copy; |
886d5463 | 1098 | bool existed; |
1099 | tree *slot = &fundef_copies_table->get_or_insert (fun, &existed); | |
1100 | ||
1101 | if (!existed) | |
4f7ebe46 | 1102 | { |
886d5463 | 1103 | /* There is no cached function available, or in use. We can use |
1104 | the function directly. That the slot is now created records | |
1105 | that this function is now in use. */ | |
1106 | copy = build_tree_list (DECL_SAVED_TREE (fun), DECL_ARGUMENTS (fun)); | |
1107 | TREE_TYPE (copy) = DECL_RESULT (fun); | |
1108 | } | |
1109 | else if (*slot == NULL_TREE) | |
1110 | { | |
1111 | /* We've already used the function itself, so make a copy. */ | |
a050099a | 1112 | copy = build_tree_list (NULL, NULL); |
a050099a | 1113 | TREE_PURPOSE (copy) = copy_fn (fun, TREE_VALUE (copy), TREE_TYPE (copy)); |
4f7ebe46 | 1114 | } |
1115 | else | |
1116 | { | |
886d5463 | 1117 | /* We have a cached function available. */ |
4f7ebe46 | 1118 | copy = *slot; |
a050099a | 1119 | *slot = TREE_CHAIN (copy); |
4f7ebe46 | 1120 | } |
1121 | ||
1122 | return copy; | |
1123 | } | |
1124 | ||
886d5463 | 1125 | /* Save the copy COPY of function FUN for later reuse by |
1126 | get_fundef_copy(). By construction, there will always be an entry | |
1127 | to find. */ | |
4f7ebe46 | 1128 | |
1129 | static void | |
a050099a | 1130 | save_fundef_copy (tree fun, tree copy) |
4f7ebe46 | 1131 | { |
886d5463 | 1132 | tree *slot = fundef_copies_table->get (fun); |
a050099a | 1133 | TREE_CHAIN (copy) = *slot; |
4f7ebe46 | 1134 | *slot = copy; |
1135 | } | |
1136 | ||
09b42213 | 1137 | /* We have an expression tree T that represents a call, either CALL_EXPR |
1138 | or AGGR_INIT_EXPR. Return the Nth argument. */ | |
1139 | ||
1140 | static inline tree | |
1141 | get_nth_callarg (tree t, int n) | |
1142 | { | |
1143 | switch (TREE_CODE (t)) | |
1144 | { | |
1145 | case CALL_EXPR: | |
1146 | return CALL_EXPR_ARG (t, n); | |
1147 | ||
1148 | case AGGR_INIT_EXPR: | |
1149 | return AGGR_INIT_EXPR_ARG (t, n); | |
1150 | ||
1151 | default: | |
1152 | gcc_unreachable (); | |
1153 | return NULL; | |
1154 | } | |
1155 | } | |
1156 | ||
09b42213 | 1157 | /* Attempt to evaluate T which represents a call to a builtin function. |
1158 | We assume here that all builtin functions evaluate to scalar types | |
1159 | represented by _CST nodes. */ | |
1160 | ||
1161 | static tree | |
f1c6af10 | 1162 | cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, |
1227ba74 | 1163 | bool lval, |
09b42213 | 1164 | bool *non_constant_p, bool *overflow_p) |
1165 | { | |
1166 | const int nargs = call_expr_nargs (t); | |
1167 | tree *args = (tree *) alloca (nargs * sizeof (tree)); | |
1168 | tree new_call; | |
1169 | int i; | |
f1c6af10 | 1170 | |
1171 | /* Don't fold __builtin_constant_p within a constexpr function. */ | |
efe6a40a | 1172 | bool bi_const_p = (DECL_FUNCTION_CODE (fun) == BUILT_IN_CONSTANT_P); |
1173 | ||
1174 | if (bi_const_p | |
f1c6af10 | 1175 | && current_function_decl |
1176 | && DECL_DECLARED_CONSTEXPR_P (current_function_decl)) | |
09b42213 | 1177 | { |
f1c6af10 | 1178 | *non_constant_p = true; |
1179 | return t; | |
09b42213 | 1180 | } |
f1c6af10 | 1181 | |
1182 | /* Be permissive for arguments to built-ins; __builtin_constant_p should | |
1183 | return constant false for a non-constant argument. */ | |
1184 | constexpr_ctx new_ctx = *ctx; | |
1185 | new_ctx.quiet = true; | |
1186 | bool dummy1 = false, dummy2 = false; | |
1187 | for (i = 0; i < nargs; ++i) | |
efe6a40a | 1188 | { |
1189 | args[i] = cxx_eval_constant_expression (&new_ctx, CALL_EXPR_ARG (t, i), | |
051eb924 | 1190 | false, &dummy1, &dummy2); |
efe6a40a | 1191 | if (bi_const_p) |
1192 | /* For __built_in_constant_p, fold all expressions with constant values | |
1193 | even if they aren't C++ constant-expressions. */ | |
1194 | args[i] = cp_fully_fold (args[i]); | |
1195 | } | |
f1c6af10 | 1196 | |
1197 | bool save_ffbcp = force_folding_builtin_constant_p; | |
1198 | force_folding_builtin_constant_p = true; | |
051eb924 | 1199 | new_call = fold_builtin_call_array (EXPR_LOCATION (t), TREE_TYPE (t), |
1200 | CALL_EXPR_FN (t), nargs, args); | |
f1c6af10 | 1201 | force_folding_builtin_constant_p = save_ffbcp; |
051eb924 | 1202 | if (new_call == NULL) |
1203 | { | |
1204 | if (!*non_constant_p && !ctx->quiet) | |
1205 | { | |
2fb20ba2 | 1206 | /* Do not allow__builtin_unreachable in constexpr function. |
1207 | The __builtin_unreachable call with BUILTINS_LOCATION | |
1208 | comes from cp_maybe_instrument_return. */ | |
1209 | if (DECL_FUNCTION_CODE (fun) == BUILT_IN_UNREACHABLE | |
1210 | && EXPR_LOCATION (t) == BUILTINS_LOCATION) | |
5967b28b | 1211 | error ("%<constexpr%> call flows off the end of the function"); |
2fb20ba2 | 1212 | else |
1213 | { | |
1214 | new_call = build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t), | |
1215 | CALL_EXPR_FN (t), nargs, args); | |
1216 | error ("%q+E is not a constant expression", new_call); | |
1217 | } | |
051eb924 | 1218 | } |
1219 | *non_constant_p = true; | |
1220 | return t; | |
1221 | } | |
1222 | ||
7e1f8be4 | 1223 | if (!is_constant_expression (new_call)) |
051eb924 | 1224 | { |
1225 | if (!*non_constant_p && !ctx->quiet) | |
1226 | error ("%q+E is not a constant expression", new_call); | |
1227 | *non_constant_p = true; | |
1228 | return t; | |
1229 | } | |
1230 | ||
1231 | return cxx_eval_constant_expression (&new_ctx, new_call, lval, | |
1232 | non_constant_p, overflow_p); | |
09b42213 | 1233 | } |
1234 | ||
1235 | /* TEMP is the constant value of a temporary object of type TYPE. Adjust | |
1236 | the type of the value to match. */ | |
1237 | ||
1238 | static tree | |
1239 | adjust_temp_type (tree type, tree temp) | |
1240 | { | |
1241 | if (TREE_TYPE (temp) == type) | |
1242 | return temp; | |
1243 | /* Avoid wrapping an aggregate value in a NOP_EXPR. */ | |
1244 | if (TREE_CODE (temp) == CONSTRUCTOR) | |
1245 | return build_constructor (type, CONSTRUCTOR_ELTS (temp)); | |
1246 | gcc_assert (scalarish_type_p (type)); | |
1247 | return cp_fold_convert (type, temp); | |
1248 | } | |
1249 | ||
e283bb4f | 1250 | /* Callback for walk_tree used by unshare_constructor. */ |
1251 | ||
1252 | static tree | |
1253 | find_constructor (tree *tp, int *walk_subtrees, void *) | |
1254 | { | |
1255 | if (TYPE_P (*tp)) | |
1256 | *walk_subtrees = 0; | |
1257 | if (TREE_CODE (*tp) == CONSTRUCTOR) | |
1258 | return *tp; | |
1259 | return NULL_TREE; | |
1260 | } | |
1261 | ||
1262 | /* If T is a CONSTRUCTOR or an expression that has a CONSTRUCTOR node as a | |
1263 | subexpression, return an unshared copy of T. Otherwise return T. */ | |
1264 | ||
1265 | static tree | |
1266 | unshare_constructor (tree t) | |
1267 | { | |
1268 | tree ctor = walk_tree (&t, find_constructor, NULL, NULL); | |
1269 | if (ctor != NULL_TREE) | |
1270 | return unshare_expr (t); | |
1271 | return t; | |
1272 | } | |
1273 | ||
09b42213 | 1274 | /* Subroutine of cxx_eval_call_expression. |
1275 | We are processing a call expression (either CALL_EXPR or | |
cf72f34d | 1276 | AGGR_INIT_EXPR) in the context of CTX. Evaluate |
09b42213 | 1277 | all arguments and bind their values to correspondings |
1278 | parameters, making up the NEW_CALL context. */ | |
1279 | ||
1280 | static void | |
cf72f34d | 1281 | cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, |
09b42213 | 1282 | constexpr_call *new_call, |
c8f6aeb1 | 1283 | bool *non_constant_p, bool *overflow_p, |
1284 | bool *non_constant_args) | |
09b42213 | 1285 | { |
1286 | const int nargs = call_expr_nargs (t); | |
1287 | tree fun = new_call->fundef->decl; | |
1288 | tree parms = DECL_ARGUMENTS (fun); | |
1289 | int i; | |
9c96033c | 1290 | tree *p = &new_call->bindings; |
09b42213 | 1291 | for (i = 0; i < nargs; ++i) |
1292 | { | |
1293 | tree x, arg; | |
1294 | tree type = parms ? TREE_TYPE (parms) : void_type_node; | |
09b42213 | 1295 | x = get_nth_callarg (t, i); |
cf72f34d | 1296 | /* For member function, the first argument is a pointer to the implied |
1297 | object. For a constructor, it might still be a dummy object, in | |
9c96033c | 1298 | which case we get the real argument from ctx. */ |
cf72f34d | 1299 | if (i == 0 && DECL_CONSTRUCTOR_P (fun) |
1300 | && is_dummy_object (x)) | |
1301 | { | |
1302 | x = ctx->object; | |
c017458d | 1303 | x = build_address (x); |
cf72f34d | 1304 | } |
2e1c71c2 | 1305 | arg = cxx_eval_constant_expression (ctx, x, /*lval=*/false, |
b2a43197 | 1306 | non_constant_p, overflow_p); |
09b42213 | 1307 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 1308 | if (*non_constant_p && ctx->quiet) |
09b42213 | 1309 | return; |
1310 | /* Just discard ellipsis args after checking their constantitude. */ | |
1311 | if (!parms) | |
1312 | continue; | |
2ba934c7 | 1313 | |
1314 | if (!*non_constant_p) | |
1315 | { | |
24d5b4f0 | 1316 | /* Don't share a CONSTRUCTOR that might be changed. */ |
1317 | arg = unshare_constructor (arg); | |
2ba934c7 | 1318 | /* Make sure the binding has the same type as the parm. But |
1319 | only for constant args. */ | |
1320 | if (TREE_CODE (type) != REFERENCE_TYPE) | |
1321 | arg = adjust_temp_type (type, arg); | |
1322 | if (!TREE_CONSTANT (arg)) | |
1323 | *non_constant_args = true; | |
1324 | *p = build_tree_list (parms, arg); | |
1325 | p = &TREE_CHAIN (*p); | |
1326 | } | |
09b42213 | 1327 | parms = TREE_CHAIN (parms); |
1328 | } | |
1329 | } | |
1330 | ||
1331 | /* Variables and functions to manage constexpr call expansion context. | |
1332 | These do not need to be marked for PCH or GC. */ | |
1333 | ||
1334 | /* FIXME remember and print actual constant arguments. */ | |
16fb756f | 1335 | static vec<tree> call_stack; |
09b42213 | 1336 | static int call_stack_tick; |
1337 | static int last_cx_error_tick; | |
1338 | ||
1339 | static bool | |
1340 | push_cx_call_context (tree call) | |
1341 | { | |
1342 | ++call_stack_tick; | |
1343 | if (!EXPR_HAS_LOCATION (call)) | |
1344 | SET_EXPR_LOCATION (call, input_location); | |
1345 | call_stack.safe_push (call); | |
1346 | if (call_stack.length () > (unsigned) max_constexpr_depth) | |
1347 | return false; | |
1348 | return true; | |
1349 | } | |
1350 | ||
1351 | static void | |
1352 | pop_cx_call_context (void) | |
1353 | { | |
1354 | ++call_stack_tick; | |
1355 | call_stack.pop (); | |
1356 | } | |
1357 | ||
1358 | vec<tree> | |
1359 | cx_error_context (void) | |
1360 | { | |
1361 | vec<tree> r = vNULL; | |
1362 | if (call_stack_tick != last_cx_error_tick | |
1363 | && !call_stack.is_empty ()) | |
1364 | r = call_stack; | |
1365 | last_cx_error_tick = call_stack_tick; | |
1366 | return r; | |
1367 | } | |
1368 | ||
732905bb | 1369 | /* Evaluate a call T to a GCC internal function when possible and return |
1370 | the evaluated result or, under the control of CTX, give an error, set | |
1371 | NON_CONSTANT_P, and return the unevaluated call T otherwise. */ | |
1372 | ||
1373 | static tree | |
1374 | cxx_eval_internal_function (const constexpr_ctx *ctx, tree t, | |
1375 | bool lval, | |
1376 | bool *non_constant_p, bool *overflow_p) | |
1377 | { | |
1378 | enum tree_code opcode = ERROR_MARK; | |
1379 | ||
1380 | switch (CALL_EXPR_IFN (t)) | |
1381 | { | |
1382 | case IFN_UBSAN_NULL: | |
1383 | case IFN_UBSAN_BOUNDS: | |
1384 | case IFN_UBSAN_VPTR: | |
3c77f69c | 1385 | case IFN_FALLTHROUGH: |
732905bb | 1386 | return void_node; |
1387 | ||
1388 | case IFN_ADD_OVERFLOW: | |
1389 | opcode = PLUS_EXPR; | |
1390 | break; | |
1391 | case IFN_SUB_OVERFLOW: | |
1392 | opcode = MINUS_EXPR; | |
1393 | break; | |
1394 | case IFN_MUL_OVERFLOW: | |
1395 | opcode = MULT_EXPR; | |
1396 | break; | |
1397 | ||
6e1b2ffb | 1398 | case IFN_LAUNDER: |
1399 | return cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), | |
1400 | false, non_constant_p, overflow_p); | |
1401 | ||
732905bb | 1402 | default: |
1403 | if (!ctx->quiet) | |
1404 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
1405 | "call to internal function %qE", t); | |
1406 | *non_constant_p = true; | |
1407 | return t; | |
1408 | } | |
1409 | ||
1410 | /* Evaluate constant arguments using OPCODE and return a complex | |
1411 | number containing the result and the overflow bit. */ | |
1412 | tree arg0 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), lval, | |
1413 | non_constant_p, overflow_p); | |
1414 | tree arg1 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 1), lval, | |
1415 | non_constant_p, overflow_p); | |
1416 | ||
1417 | if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) | |
1418 | { | |
1419 | location_t loc = EXPR_LOC_OR_LOC (t, input_location); | |
1420 | tree type = TREE_TYPE (TREE_TYPE (t)); | |
1421 | tree result = fold_binary_loc (loc, opcode, type, | |
1422 | fold_convert_loc (loc, type, arg0), | |
1423 | fold_convert_loc (loc, type, arg1)); | |
1424 | tree ovf | |
1425 | = build_int_cst (type, arith_overflowed_p (opcode, type, arg0, arg1)); | |
1426 | /* Reset TREE_OVERFLOW to avoid warnings for the overflow. */ | |
1427 | if (TREE_OVERFLOW (result)) | |
1428 | TREE_OVERFLOW (result) = 0; | |
1429 | ||
1430 | return build_complex (TREE_TYPE (t), result, ovf); | |
1431 | } | |
1432 | ||
1433 | *non_constant_p = true; | |
1434 | return t; | |
1435 | } | |
1436 | ||
79cdb4f5 | 1437 | /* Clean CONSTRUCTOR_NO_IMPLICIT_ZERO from CTOR and its sub-aggregates. */ |
1438 | ||
1439 | static void | |
1440 | clear_no_implicit_zero (tree ctor) | |
1441 | { | |
1442 | if (CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor)) | |
1443 | { | |
1444 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor) = false; | |
1445 | tree elt; unsigned HOST_WIDE_INT idx; | |
1446 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (ctor), idx, elt) | |
1447 | if (TREE_CODE (elt) == CONSTRUCTOR) | |
1448 | clear_no_implicit_zero (elt); | |
1449 | } | |
1450 | } | |
1451 | ||
09b42213 | 1452 | /* Subroutine of cxx_eval_constant_expression. |
1453 | Evaluate the call expression tree T in the context of OLD_CALL expression | |
1454 | evaluation. */ | |
1455 | ||
1456 | static tree | |
cf72f34d | 1457 | cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1458 | bool lval, |
09b42213 | 1459 | bool *non_constant_p, bool *overflow_p) |
1460 | { | |
1461 | location_t loc = EXPR_LOC_OR_LOC (t, input_location); | |
1462 | tree fun = get_function_named_in_call (t); | |
09b42213 | 1463 | constexpr_call new_call = { NULL, NULL, NULL, 0 }; |
09b42213 | 1464 | bool depth_ok; |
1465 | ||
6b71bdb4 | 1466 | if (fun == NULL_TREE) |
732905bb | 1467 | return cxx_eval_internal_function (ctx, t, lval, |
1468 | non_constant_p, overflow_p); | |
6b71bdb4 | 1469 | |
09b42213 | 1470 | if (TREE_CODE (fun) != FUNCTION_DECL) |
1471 | { | |
1472 | /* Might be a constexpr function pointer. */ | |
f83e6885 | 1473 | fun = cxx_eval_constant_expression (ctx, fun, |
1227ba74 | 1474 | /*lval*/false, non_constant_p, |
b2a43197 | 1475 | overflow_p); |
09b42213 | 1476 | STRIP_NOPS (fun); |
1477 | if (TREE_CODE (fun) == ADDR_EXPR) | |
1478 | fun = TREE_OPERAND (fun, 0); | |
1479 | } | |
1480 | if (TREE_CODE (fun) != FUNCTION_DECL) | |
1481 | { | |
f83e6885 | 1482 | if (!ctx->quiet && !*non_constant_p) |
5967b28b | 1483 | error_at (loc, "expression %qE does not designate a %<constexpr%> " |
09b42213 | 1484 | "function", fun); |
1485 | *non_constant_p = true; | |
1486 | return t; | |
1487 | } | |
1488 | if (DECL_CLONED_FUNCTION_P (fun)) | |
1489 | fun = DECL_CLONED_FUNCTION (fun); | |
6b71bdb4 | 1490 | |
1491 | if (is_ubsan_builtin_p (fun)) | |
1492 | return void_node; | |
1493 | ||
09b42213 | 1494 | if (is_builtin_fn (fun)) |
f1c6af10 | 1495 | return cxx_eval_builtin_function_call (ctx, t, fun, |
1227ba74 | 1496 | lval, non_constant_p, overflow_p); |
09b42213 | 1497 | if (!DECL_DECLARED_CONSTEXPR_P (fun)) |
1498 | { | |
f83e6885 | 1499 | if (!ctx->quiet) |
09b42213 | 1500 | { |
1dcd84cf | 1501 | if (!lambda_static_thunk_p (fun)) |
5967b28b | 1502 | error_at (loc, "call to non-%<constexpr%> function %qD", fun); |
09b42213 | 1503 | explain_invalid_constexpr_fn (fun); |
1504 | } | |
1505 | *non_constant_p = true; | |
1506 | return t; | |
1507 | } | |
1508 | ||
9ebe2ea3 | 1509 | constexpr_ctx new_ctx = *ctx; |
1510 | if (DECL_CONSTRUCTOR_P (fun) && !ctx->object | |
1511 | && TREE_CODE (t) == AGGR_INIT_EXPR) | |
1512 | { | |
1513 | /* We want to have an initialization target for an AGGR_INIT_EXPR. | |
1514 | If we don't already have one in CTX, use the AGGR_INIT_EXPR_SLOT. */ | |
1515 | new_ctx.object = AGGR_INIT_EXPR_SLOT (t); | |
1516 | tree ctor = new_ctx.ctor = build_constructor (DECL_CONTEXT (fun), NULL); | |
1517 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor) = true; | |
1518 | ctx->values->put (new_ctx.object, ctor); | |
1519 | ctx = &new_ctx; | |
1520 | } | |
1521 | ||
09b42213 | 1522 | /* Shortcut trivial constructor/op=. */ |
1523 | if (trivial_fn_p (fun)) | |
1524 | { | |
9ebe2ea3 | 1525 | tree init = NULL_TREE; |
09b42213 | 1526 | if (call_expr_nargs (t) == 2) |
9ebe2ea3 | 1527 | init = convert_from_reference (get_nth_callarg (t, 1)); |
09b42213 | 1528 | else if (TREE_CODE (t) == AGGR_INIT_EXPR |
1529 | && AGGR_INIT_ZERO_FIRST (t)) | |
9ebe2ea3 | 1530 | init = build_zero_init (DECL_CONTEXT (fun), NULL_TREE, false); |
1531 | if (init) | |
1532 | { | |
1533 | tree op = get_nth_callarg (t, 0); | |
1534 | if (is_dummy_object (op)) | |
1535 | op = ctx->object; | |
1536 | else | |
1537 | op = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (op)), op); | |
1538 | tree set = build2 (MODIFY_EXPR, TREE_TYPE (op), op, init); | |
0ce12360 | 1539 | new_ctx.call = &new_call; |
1540 | return cxx_eval_constant_expression (&new_ctx, set, lval, | |
9ebe2ea3 | 1541 | non_constant_p, overflow_p); |
1542 | } | |
09b42213 | 1543 | } |
1544 | ||
8afcf831 | 1545 | /* We can't defer instantiating the function any longer. */ |
1546 | if (!DECL_INITIAL (fun) | |
1547 | && DECL_TEMPLOID_INSTANTIATION (fun)) | |
1548 | { | |
31db86df | 1549 | location_t save_loc = input_location; |
1550 | input_location = loc; | |
8afcf831 | 1551 | ++function_depth; |
1552 | instantiate_decl (fun, /*defer_ok*/false, /*expl_inst*/false); | |
1553 | --function_depth; | |
31db86df | 1554 | input_location = save_loc; |
8afcf831 | 1555 | } |
1556 | ||
09b42213 | 1557 | /* If in direct recursive call, optimize definition search. */ |
0ce12360 | 1558 | if (ctx && ctx->call && ctx->call->fundef && ctx->call->fundef->decl == fun) |
cf72f34d | 1559 | new_call.fundef = ctx->call->fundef; |
09b42213 | 1560 | else |
1561 | { | |
1562 | new_call.fundef = retrieve_constexpr_fundef (fun); | |
d2a9b1c1 | 1563 | if (new_call.fundef == NULL || new_call.fundef->body == NULL |
1564 | || fun == current_function_decl) | |
09b42213 | 1565 | { |
f83e6885 | 1566 | if (!ctx->quiet) |
09b42213 | 1567 | { |
d2a9b1c1 | 1568 | /* We need to check for current_function_decl here in case we're |
1569 | being called during cp_fold_function, because at that point | |
1570 | DECL_INITIAL is set properly and we have a fundef but we | |
1571 | haven't lowered invisirefs yet (c++/70344). */ | |
1572 | if (DECL_INITIAL (fun) == error_mark_node | |
1573 | || fun == current_function_decl) | |
a0efa758 | 1574 | error_at (loc, "%qD called in a constant expression before its " |
1575 | "definition is complete", fun); | |
1576 | else if (DECL_INITIAL (fun)) | |
09b42213 | 1577 | { |
33603066 | 1578 | /* The definition of fun was somehow unsuitable. But pretend |
1579 | that lambda static thunks don't exist. */ | |
1580 | if (!lambda_static_thunk_p (fun)) | |
1581 | error_at (loc, "%qD called in a constant expression", fun); | |
09b42213 | 1582 | explain_invalid_constexpr_fn (fun); |
1583 | } | |
1584 | else | |
1585 | error_at (loc, "%qD used before its definition", fun); | |
1586 | } | |
1587 | *non_constant_p = true; | |
1588 | return t; | |
1589 | } | |
1590 | } | |
9c96033c | 1591 | |
c8f6aeb1 | 1592 | bool non_constant_args = false; |
cf72f34d | 1593 | cxx_bind_parameters_in_call (ctx, t, &new_call, |
c8f6aeb1 | 1594 | non_constant_p, overflow_p, &non_constant_args); |
09b42213 | 1595 | if (*non_constant_p) |
1596 | return t; | |
1597 | ||
1598 | depth_ok = push_cx_call_context (t); | |
1599 | ||
c8f6aeb1 | 1600 | tree result = NULL_TREE; |
09b42213 | 1601 | |
c8f6aeb1 | 1602 | constexpr_call *entry = NULL; |
167a09fb | 1603 | if (depth_ok && !non_constant_args && ctx->strict) |
09b42213 | 1604 | { |
c8f6aeb1 | 1605 | new_call.hash = iterative_hash_template_arg |
1606 | (new_call.bindings, constexpr_fundef_hasher::hash (new_call.fundef)); | |
1607 | ||
1608 | /* If we have seen this call before, we are done. */ | |
1609 | maybe_initialize_constexpr_call_table (); | |
1610 | constexpr_call **slot | |
1611 | = constexpr_call_table->find_slot (&new_call, INSERT); | |
1612 | entry = *slot; | |
1613 | if (entry == NULL) | |
1614 | { | |
1615 | /* We need to keep a pointer to the entry, not just the slot, as the | |
1616 | slot can move in the call to cxx_eval_builtin_function_call. */ | |
1617 | *slot = entry = ggc_alloc<constexpr_call> (); | |
1618 | *entry = new_call; | |
1619 | } | |
2ba934c7 | 1620 | /* Calls that are in progress have their result set to NULL, |
c8f6aeb1 | 1621 | so that we can detect circular dependencies. */ |
1622 | else if (entry->result == NULL) | |
1623 | { | |
1624 | if (!ctx->quiet) | |
1625 | error ("call has circular dependency"); | |
1626 | *non_constant_p = true; | |
1627 | entry->result = result = error_mark_node; | |
1628 | } | |
1629 | else | |
1630 | result = entry->result; | |
09b42213 | 1631 | } |
1632 | ||
1633 | if (!depth_ok) | |
1634 | { | |
f83e6885 | 1635 | if (!ctx->quiet) |
5967b28b | 1636 | error ("%<constexpr%> evaluation depth exceeds maximum of %d (use " |
09b42213 | 1637 | "-fconstexpr-depth= to increase the maximum)", |
1638 | max_constexpr_depth); | |
1639 | *non_constant_p = true; | |
c8f6aeb1 | 1640 | result = error_mark_node; |
09b42213 | 1641 | } |
1642 | else | |
1643 | { | |
ab099088 | 1644 | if (result && result != error_mark_node) |
1645 | /* OK */; | |
1646 | else if (!DECL_SAVED_TREE (fun)) | |
1647 | { | |
1648 | /* When at_eof >= 2, cgraph has started throwing away | |
1649 | DECL_SAVED_TREE, so fail quietly. FIXME we get here because of | |
1650 | late code generation for VEC_INIT_EXPR, which needs to be | |
1651 | completely reconsidered. */ | |
1652 | gcc_assert (at_eof >= 2 && ctx->quiet); | |
1653 | *non_constant_p = true; | |
1654 | } | |
1655 | else | |
cf72f34d | 1656 | { |
4f7ebe46 | 1657 | tree body, parms, res; |
88a59139 | 1658 | |
4f7ebe46 | 1659 | /* Reuse or create a new unshared copy of this function's body. */ |
a050099a | 1660 | tree copy = get_fundef_copy (fun); |
1661 | body = TREE_PURPOSE (copy); | |
1662 | parms = TREE_VALUE (copy); | |
1663 | res = TREE_TYPE (copy); | |
88a59139 | 1664 | |
1665 | /* Associate the bindings with the remapped parms. */ | |
1666 | tree bound = new_call.bindings; | |
1667 | tree remapped = parms; | |
1668 | while (bound) | |
9c96033c | 1669 | { |
88a59139 | 1670 | tree oparm = TREE_PURPOSE (bound); |
1671 | tree arg = TREE_VALUE (bound); | |
1672 | gcc_assert (DECL_NAME (remapped) == DECL_NAME (oparm)); | |
5898f0d7 | 1673 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 1674 | arg = unshare_constructor (arg); |
88a59139 | 1675 | ctx->values->put (remapped, arg); |
1676 | bound = TREE_CHAIN (bound); | |
1677 | remapped = DECL_CHAIN (remapped); | |
9c96033c | 1678 | } |
88a59139 | 1679 | /* Add the RESULT_DECL to the values map, too. */ |
1680 | tree slot = NULL_TREE; | |
1681 | if (DECL_BY_REFERENCE (res)) | |
9c96033c | 1682 | { |
88a59139 | 1683 | slot = AGGR_INIT_EXPR_SLOT (t); |
1684 | tree addr = build_address (slot); | |
1685 | addr = build_nop (TREE_TYPE (res), addr); | |
1686 | ctx->values->put (res, addr); | |
1687 | ctx->values->put (slot, NULL_TREE); | |
1688 | } | |
1689 | else | |
1690 | ctx->values->put (res, NULL_TREE); | |
9c96033c | 1691 | |
4f7ebe46 | 1692 | /* Track the callee's evaluated SAVE_EXPRs so that we can forget |
1693 | their values after the call. */ | |
1694 | constexpr_ctx ctx_with_save_exprs = *ctx; | |
1695 | hash_set<tree> save_exprs; | |
1696 | ctx_with_save_exprs.save_exprs = &save_exprs; | |
43b7271d | 1697 | ctx_with_save_exprs.call = &new_call; |
4f7ebe46 | 1698 | |
88a59139 | 1699 | tree jump_target = NULL_TREE; |
4f7ebe46 | 1700 | cxx_eval_constant_expression (&ctx_with_save_exprs, body, |
88a59139 | 1701 | lval, non_constant_p, overflow_p, |
1702 | &jump_target); | |
9c96033c | 1703 | |
88a59139 | 1704 | if (DECL_CONSTRUCTOR_P (fun)) |
1705 | /* This can be null for a subobject constructor call, in | |
1706 | which case what we care about is the initialization | |
1707 | side-effects rather than the value. We could get at the | |
1708 | value by evaluating *this, but we don't bother; there's | |
1709 | no need to put such a call in the hash table. */ | |
1710 | result = lval ? ctx->object : ctx->ctor; | |
1711 | else if (VOID_TYPE_P (TREE_TYPE (res))) | |
1712 | result = void_node; | |
1713 | else | |
1714 | { | |
1715 | result = *ctx->values->get (slot ? slot : res); | |
1716 | if (result == NULL_TREE && !*non_constant_p) | |
9c96033c | 1717 | { |
88a59139 | 1718 | if (!ctx->quiet) |
5967b28b | 1719 | error ("%<constexpr%> call flows off the end " |
88a59139 | 1720 | "of the function"); |
1721 | *non_constant_p = true; | |
9c96033c | 1722 | } |
9c96033c | 1723 | } |
88a59139 | 1724 | |
4f7ebe46 | 1725 | /* Forget the saved values of the callee's SAVE_EXPRs. */ |
1726 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
1727 | iter != save_exprs.end(); ++iter) | |
1728 | ctx_with_save_exprs.values->remove (*iter); | |
1729 | ||
88a59139 | 1730 | /* Remove the parms/result from the values map. Is it worth |
1731 | bothering to do this when the map itself is only live for | |
1732 | one constexpr evaluation? If so, maybe also clear out | |
1733 | other vars from call, maybe in BIND_EXPR handling? */ | |
1734 | ctx->values->remove (res); | |
1735 | if (slot) | |
1736 | ctx->values->remove (slot); | |
1737 | for (tree parm = parms; parm; parm = TREE_CHAIN (parm)) | |
1738 | ctx->values->remove (parm); | |
4f7ebe46 | 1739 | |
1740 | /* Make the unshared function copy we used available for re-use. */ | |
1741 | save_fundef_copy (fun, copy); | |
cf72f34d | 1742 | } |
9c96033c | 1743 | |
09b42213 | 1744 | if (result == error_mark_node) |
1745 | *non_constant_p = true; | |
c3f376bf | 1746 | if (*non_constant_p || *overflow_p) |
c8f6aeb1 | 1747 | result = error_mark_node; |
88a59139 | 1748 | else if (!result) |
9c96033c | 1749 | result = void_node; |
c8f6aeb1 | 1750 | if (entry) |
1751 | entry->result = result; | |
09b42213 | 1752 | } |
1753 | ||
c6d97004 | 1754 | /* The result of a constexpr function must be completely initialized. */ |
1755 | if (TREE_CODE (result) == CONSTRUCTOR) | |
79cdb4f5 | 1756 | clear_no_implicit_zero (result); |
c6d97004 | 1757 | |
09b42213 | 1758 | pop_cx_call_context (); |
e283bb4f | 1759 | return unshare_constructor (result); |
09b42213 | 1760 | } |
1761 | ||
1762 | /* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */ | |
1763 | ||
1764 | bool | |
1765 | reduced_constant_expression_p (tree t) | |
1766 | { | |
1767 | switch (TREE_CODE (t)) | |
1768 | { | |
1769 | case PTRMEM_CST: | |
1770 | /* Even if we can't lower this yet, it's constant. */ | |
1771 | return true; | |
1772 | ||
1773 | case CONSTRUCTOR: | |
1774 | /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */ | |
56da7fe6 | 1775 | tree idx, val, field; unsigned HOST_WIDE_INT i; |
1776 | if (CONSTRUCTOR_NO_IMPLICIT_ZERO (t)) | |
c4210852 | 1777 | { |
1778 | if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE) | |
1779 | /* An initialized vector would have a VECTOR_CST. */ | |
1780 | return false; | |
1781 | else | |
1782 | field = next_initializable_field (TYPE_FIELDS (TREE_TYPE (t))); | |
1783 | } | |
56da7fe6 | 1784 | else |
1785 | field = NULL_TREE; | |
1786 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t), i, idx, val) | |
ce4ffd9e | 1787 | { |
56da7fe6 | 1788 | if (!val) |
ce4ffd9e | 1789 | /* We're in the middle of initializing this element. */ |
1790 | return false; | |
56da7fe6 | 1791 | if (!reduced_constant_expression_p (val)) |
ce4ffd9e | 1792 | return false; |
56da7fe6 | 1793 | if (field) |
1794 | { | |
1795 | if (idx != field) | |
1796 | return false; | |
1797 | field = next_initializable_field (DECL_CHAIN (field)); | |
1798 | } | |
ce4ffd9e | 1799 | } |
56da7fe6 | 1800 | if (field) |
1801 | return false; | |
1802 | else if (CONSTRUCTOR_NO_IMPLICIT_ZERO (t)) | |
1803 | /* All the fields are initialized. */ | |
1804 | CONSTRUCTOR_NO_IMPLICIT_ZERO (t) = false; | |
09b42213 | 1805 | return true; |
1806 | ||
1807 | default: | |
1808 | /* FIXME are we calling this too much? */ | |
1809 | return initializer_constant_valid_p (t, TREE_TYPE (t)) != NULL_TREE; | |
1810 | } | |
1811 | } | |
1812 | ||
1813 | /* Some expressions may have constant operands but are not constant | |
1814 | themselves, such as 1/0. Call this function (or rather, the macro | |
1815 | following it) to check for that condition. | |
1816 | ||
1817 | We only call this in places that require an arithmetic constant, not in | |
1818 | places where we might have a non-constant expression that can be a | |
1819 | component of a constant expression, such as the address of a constexpr | |
1820 | variable that might be dereferenced later. */ | |
1821 | ||
1822 | static bool | |
1823 | verify_constant (tree t, bool allow_non_constant, bool *non_constant_p, | |
1824 | bool *overflow_p) | |
1825 | { | |
1826 | if (!*non_constant_p && !reduced_constant_expression_p (t)) | |
1827 | { | |
1828 | if (!allow_non_constant) | |
1829 | error ("%q+E is not a constant expression", t); | |
1830 | *non_constant_p = true; | |
1831 | } | |
1832 | if (TREE_OVERFLOW_P (t)) | |
1833 | { | |
1834 | if (!allow_non_constant) | |
1835 | { | |
1836 | permerror (input_location, "overflow in constant expression"); | |
1837 | /* If we're being permissive (and are in an enforcing | |
1838 | context), ignore the overflow. */ | |
1839 | if (flag_permissive) | |
1840 | return *non_constant_p; | |
1841 | } | |
1842 | *overflow_p = true; | |
1843 | } | |
1844 | return *non_constant_p; | |
1845 | } | |
1846 | ||
2b035ffe | 1847 | /* Check whether the shift operation with code CODE and type TYPE on LHS |
1848 | and RHS is undefined. If it is, give an error with an explanation, | |
1849 | and return true; return false otherwise. */ | |
1850 | ||
1851 | static bool | |
1852 | cxx_eval_check_shift_p (location_t loc, const constexpr_ctx *ctx, | |
1853 | enum tree_code code, tree type, tree lhs, tree rhs) | |
1854 | { | |
1855 | if ((code != LSHIFT_EXPR && code != RSHIFT_EXPR) | |
1856 | || TREE_CODE (lhs) != INTEGER_CST | |
1857 | || TREE_CODE (rhs) != INTEGER_CST) | |
1858 | return false; | |
1859 | ||
1860 | tree lhstype = TREE_TYPE (lhs); | |
1861 | unsigned HOST_WIDE_INT uprec = TYPE_PRECISION (TREE_TYPE (lhs)); | |
1862 | ||
1863 | /* [expr.shift] The behavior is undefined if the right operand | |
1864 | is negative, or greater than or equal to the length in bits | |
1865 | of the promoted left operand. */ | |
1866 | if (tree_int_cst_sgn (rhs) == -1) | |
1867 | { | |
1868 | if (!ctx->quiet) | |
91d87e22 | 1869 | permerror (loc, "right operand of shift expression %q+E is negative", |
1870 | build2_loc (loc, code, type, lhs, rhs)); | |
1871 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1872 | } |
1873 | if (compare_tree_int (rhs, uprec) >= 0) | |
1874 | { | |
1875 | if (!ctx->quiet) | |
91d87e22 | 1876 | permerror (loc, "right operand of shift expression %q+E is >= than " |
1877 | "the precision of the left operand", | |
1878 | build2_loc (loc, code, type, lhs, rhs)); | |
1879 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1880 | } |
1881 | ||
1882 | /* The value of E1 << E2 is E1 left-shifted E2 bit positions; [...] | |
1883 | if E1 has a signed type and non-negative value, and E1x2^E2 is | |
1884 | representable in the corresponding unsigned type of the result type, | |
1885 | then that value, converted to the result type, is the resulting value; | |
1886 | otherwise, the behavior is undefined. */ | |
1887 | if (code == LSHIFT_EXPR && !TYPE_UNSIGNED (lhstype) | |
1888 | && (cxx_dialect >= cxx11)) | |
1889 | { | |
1890 | if (tree_int_cst_sgn (lhs) == -1) | |
1891 | { | |
1892 | if (!ctx->quiet) | |
91d87e22 | 1893 | permerror (loc, |
1894 | "left operand of shift expression %q+E is negative", | |
1895 | build2_loc (loc, code, type, lhs, rhs)); | |
1896 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1897 | } |
1898 | /* For signed x << y the following: | |
1899 | (unsigned) x >> ((prec (lhs) - 1) - y) | |
1900 | if > 1, is undefined. The right-hand side of this formula | |
1901 | is the highest bit of the LHS that can be set (starting from 0), | |
1902 | so that the shift doesn't overflow. We then right-shift the LHS | |
1903 | to see whether any other bit is set making the original shift | |
1904 | undefined -- the result is not representable in the corresponding | |
1905 | unsigned type. */ | |
1906 | tree t = build_int_cst (unsigned_type_node, uprec - 1); | |
1907 | t = fold_build2 (MINUS_EXPR, unsigned_type_node, t, rhs); | |
1908 | tree ulhs = fold_convert (unsigned_type_for (lhstype), lhs); | |
1909 | t = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ulhs), ulhs, t); | |
1910 | if (tree_int_cst_lt (integer_one_node, t)) | |
1911 | { | |
1912 | if (!ctx->quiet) | |
91d87e22 | 1913 | permerror (loc, "shift expression %q+E overflows", |
1914 | build2_loc (loc, code, type, lhs, rhs)); | |
1915 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1916 | } |
1917 | } | |
1918 | return false; | |
1919 | } | |
1920 | ||
09b42213 | 1921 | /* Subroutine of cxx_eval_constant_expression. |
1922 | Attempt to reduce the unary expression tree T to a compile time value. | |
1923 | If successful, return the value. Otherwise issue a diagnostic | |
1924 | and return error_mark_node. */ | |
1925 | ||
1926 | static tree | |
cf72f34d | 1927 | cxx_eval_unary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 1928 | bool /*lval*/, |
09b42213 | 1929 | bool *non_constant_p, bool *overflow_p) |
1930 | { | |
1931 | tree r; | |
1932 | tree orig_arg = TREE_OPERAND (t, 0); | |
c8f6aeb1 | 1933 | tree arg = cxx_eval_constant_expression (ctx, orig_arg, /*lval*/false, |
1934 | non_constant_p, overflow_p); | |
09b42213 | 1935 | VERIFY_CONSTANT (arg); |
93add516 | 1936 | location_t loc = EXPR_LOCATION (t); |
1937 | enum tree_code code = TREE_CODE (t); | |
1938 | tree type = TREE_TYPE (t); | |
1939 | r = fold_unary_loc (loc, code, type, arg); | |
1940 | if (r == NULL_TREE) | |
1941 | { | |
1942 | if (arg == orig_arg) | |
1943 | r = t; | |
1944 | else | |
1945 | r = build1_loc (loc, code, type, arg); | |
1946 | } | |
09b42213 | 1947 | VERIFY_CONSTANT (r); |
1948 | return r; | |
1949 | } | |
1950 | ||
46fad8d5 | 1951 | /* Helper function for cxx_eval_binary_expression. Try to optimize |
1952 | original POINTER_PLUS_EXPR T, LHS p+ RHS, return NULL_TREE if the | |
1953 | generic folding should be used. */ | |
1954 | ||
1955 | static tree | |
1956 | cxx_fold_pointer_plus_expression (const constexpr_ctx *ctx, tree t, | |
1957 | tree lhs, tree rhs, bool *non_constant_p, | |
1958 | bool *overflow_p) | |
1959 | { | |
1960 | STRIP_NOPS (lhs); | |
1961 | if (TREE_CODE (lhs) != ADDR_EXPR) | |
1962 | return NULL_TREE; | |
1963 | ||
1964 | lhs = TREE_OPERAND (lhs, 0); | |
1965 | ||
1966 | /* &A[i] p+ j => &A[i + j] */ | |
1967 | if (TREE_CODE (lhs) == ARRAY_REF | |
1968 | && TREE_CODE (TREE_OPERAND (lhs, 1)) == INTEGER_CST | |
1969 | && TREE_CODE (rhs) == INTEGER_CST | |
1970 | && TYPE_SIZE_UNIT (TREE_TYPE (lhs)) | |
1971 | && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (lhs))) == INTEGER_CST) | |
1972 | { | |
1973 | tree orig_type = TREE_TYPE (t); | |
1974 | location_t loc = EXPR_LOCATION (t); | |
1975 | tree type = TREE_TYPE (lhs); | |
1976 | ||
1977 | t = fold_convert_loc (loc, ssizetype, TREE_OPERAND (lhs, 1)); | |
1978 | tree nelts = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (lhs, 0))); | |
1979 | nelts = cxx_eval_constant_expression (ctx, nelts, false, non_constant_p, | |
1980 | overflow_p); | |
1981 | if (*non_constant_p) | |
1982 | return NULL_TREE; | |
1983 | /* Don't fold an out-of-bound access. */ | |
1984 | if (!tree_int_cst_le (t, nelts)) | |
1985 | return NULL_TREE; | |
1986 | rhs = cp_fold_convert (ssizetype, rhs); | |
1987 | /* Don't fold if rhs can't be divided exactly by TYPE_SIZE_UNIT. | |
1988 | constexpr int A[1]; ... (char *)&A[0] + 1 */ | |
1989 | if (!integer_zerop (fold_build2_loc (loc, TRUNC_MOD_EXPR, sizetype, | |
1990 | rhs, TYPE_SIZE_UNIT (type)))) | |
1991 | return NULL_TREE; | |
1992 | /* Make sure to treat the second operand of POINTER_PLUS_EXPR | |
1993 | as signed. */ | |
1994 | rhs = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, rhs, | |
1995 | TYPE_SIZE_UNIT (type)); | |
1996 | t = size_binop_loc (loc, PLUS_EXPR, rhs, t); | |
1997 | t = build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (lhs, 0), | |
1998 | t, NULL_TREE, NULL_TREE); | |
1999 | t = cp_build_addr_expr (t, tf_warning_or_error); | |
2000 | t = cp_fold_convert (orig_type, t); | |
2001 | return cxx_eval_constant_expression (ctx, t, /*lval*/false, | |
2002 | non_constant_p, overflow_p); | |
2003 | } | |
2004 | ||
2005 | return NULL_TREE; | |
2006 | } | |
2007 | ||
09b42213 | 2008 | /* Subroutine of cxx_eval_constant_expression. |
2009 | Like cxx_eval_unary_expression, except for binary expressions. */ | |
2010 | ||
2011 | static tree | |
cf72f34d | 2012 | cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 2013 | bool /*lval*/, |
09b42213 | 2014 | bool *non_constant_p, bool *overflow_p) |
2015 | { | |
f7ef5392 | 2016 | tree r = NULL_TREE; |
09b42213 | 2017 | tree orig_lhs = TREE_OPERAND (t, 0); |
2018 | tree orig_rhs = TREE_OPERAND (t, 1); | |
2019 | tree lhs, rhs; | |
c8f6aeb1 | 2020 | lhs = cxx_eval_constant_expression (ctx, orig_lhs, /*lval*/false, |
b2a43197 | 2021 | non_constant_p, overflow_p); |
6d6737d9 | 2022 | /* Don't VERIFY_CONSTANT here, it's unnecessary and will break pointer |
2023 | subtraction. */ | |
2024 | if (*non_constant_p) | |
2025 | return t; | |
c8f6aeb1 | 2026 | rhs = cxx_eval_constant_expression (ctx, orig_rhs, /*lval*/false, |
b2a43197 | 2027 | non_constant_p, overflow_p); |
6d6737d9 | 2028 | if (*non_constant_p) |
2029 | return t; | |
93add516 | 2030 | |
2031 | location_t loc = EXPR_LOCATION (t); | |
2032 | enum tree_code code = TREE_CODE (t); | |
2033 | tree type = TREE_TYPE (t); | |
f7ef5392 | 2034 | |
2035 | if (code == EQ_EXPR || code == NE_EXPR) | |
2036 | { | |
2037 | bool is_code_eq = (code == EQ_EXPR); | |
2038 | ||
2039 | if (TREE_CODE (lhs) == PTRMEM_CST | |
2040 | && TREE_CODE (rhs) == PTRMEM_CST) | |
2041 | r = constant_boolean_node (cp_tree_equal (lhs, rhs) == is_code_eq, | |
2042 | type); | |
2043 | else if ((TREE_CODE (lhs) == PTRMEM_CST | |
2044 | || TREE_CODE (rhs) == PTRMEM_CST) | |
2045 | && (null_member_pointer_value_p (lhs) | |
2046 | || null_member_pointer_value_p (rhs))) | |
2047 | r = constant_boolean_node (!is_code_eq, type); | |
f31f4e9c | 2048 | else if (TREE_CODE (lhs) == PTRMEM_CST) |
2049 | lhs = cplus_expand_constant (lhs); | |
2050 | else if (TREE_CODE (rhs) == PTRMEM_CST) | |
2051 | rhs = cplus_expand_constant (rhs); | |
f7ef5392 | 2052 | } |
cb768824 | 2053 | if (code == POINTER_PLUS_EXPR && !*non_constant_p |
2054 | && integer_zerop (lhs) && !integer_zerop (rhs)) | |
2055 | { | |
2056 | if (!ctx->quiet) | |
2057 | error ("arithmetic involving a null pointer in %qE", lhs); | |
2058 | return t; | |
2059 | } | |
46fad8d5 | 2060 | else if (code == POINTER_PLUS_EXPR) |
2061 | r = cxx_fold_pointer_plus_expression (ctx, t, lhs, rhs, non_constant_p, | |
2062 | overflow_p); | |
f7ef5392 | 2063 | |
2064 | if (r == NULL_TREE) | |
2065 | r = fold_binary_loc (loc, code, type, lhs, rhs); | |
2066 | ||
93add516 | 2067 | if (r == NULL_TREE) |
2068 | { | |
2069 | if (lhs == orig_lhs && rhs == orig_rhs) | |
2070 | r = t; | |
2071 | else | |
2072 | r = build2_loc (loc, code, type, lhs, rhs); | |
2073 | } | |
2b035ffe | 2074 | else if (cxx_eval_check_shift_p (loc, ctx, code, type, lhs, rhs)) |
2075 | *non_constant_p = true; | |
6d6737d9 | 2076 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
2077 | a local array in a constexpr function. */ | |
2078 | bool ptr = POINTER_TYPE_P (TREE_TYPE (lhs)); | |
35f2c28f | 2079 | if (!ptr) |
aae7465c | 2080 | VERIFY_CONSTANT (r); |
09b42213 | 2081 | return r; |
2082 | } | |
2083 | ||
2084 | /* Subroutine of cxx_eval_constant_expression. | |
2085 | Attempt to evaluate condition expressions. Dead branches are not | |
2086 | looked into. */ | |
2087 | ||
2088 | static tree | |
cf72f34d | 2089 | cxx_eval_conditional_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2090 | bool lval, |
00f21715 | 2091 | bool *non_constant_p, bool *overflow_p, |
2092 | tree *jump_target) | |
09b42213 | 2093 | { |
cf72f34d | 2094 | tree val = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
c8f6aeb1 | 2095 | /*lval*/false, |
b2a43197 | 2096 | non_constant_p, overflow_p); |
09b42213 | 2097 | VERIFY_CONSTANT (val); |
2098 | /* Don't VERIFY_CONSTANT the other operands. */ | |
2099 | if (integer_zerop (val)) | |
cf72f34d | 2100 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), |
1227ba74 | 2101 | lval, |
00f21715 | 2102 | non_constant_p, overflow_p, |
2103 | jump_target); | |
cf72f34d | 2104 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2105 | lval, |
00f21715 | 2106 | non_constant_p, overflow_p, |
2107 | jump_target); | |
09b42213 | 2108 | } |
2109 | ||
31595caf | 2110 | /* Subroutine of cxx_eval_constant_expression. |
2111 | Attempt to evaluate vector condition expressions. Unlike | |
2112 | cxx_eval_conditional_expression, VEC_COND_EXPR acts like a normal | |
2113 | ternary arithmetics operation, where all 3 arguments have to be | |
2114 | evaluated as constants and then folding computes the result from | |
2115 | them. */ | |
2116 | ||
2117 | static tree | |
2118 | cxx_eval_vector_conditional_expression (const constexpr_ctx *ctx, tree t, | |
2119 | bool *non_constant_p, bool *overflow_p) | |
2120 | { | |
2121 | tree arg1 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
2122 | /*lval*/false, | |
2123 | non_constant_p, overflow_p); | |
2124 | VERIFY_CONSTANT (arg1); | |
2125 | tree arg2 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
2126 | /*lval*/false, | |
2127 | non_constant_p, overflow_p); | |
2128 | VERIFY_CONSTANT (arg2); | |
2129 | tree arg3 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
2130 | /*lval*/false, | |
2131 | non_constant_p, overflow_p); | |
2132 | VERIFY_CONSTANT (arg3); | |
2133 | location_t loc = EXPR_LOCATION (t); | |
2134 | tree type = TREE_TYPE (t); | |
2135 | tree r = fold_ternary_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2136 | if (r == NULL_TREE) | |
2137 | { | |
2138 | if (arg1 == TREE_OPERAND (t, 0) | |
2139 | && arg2 == TREE_OPERAND (t, 1) | |
2140 | && arg3 == TREE_OPERAND (t, 2)) | |
2141 | r = t; | |
2142 | else | |
2143 | r = build3_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2144 | } | |
2145 | VERIFY_CONSTANT (r); | |
2146 | return r; | |
2147 | } | |
2148 | ||
7963b19d | 2149 | /* Returns less than, equal to, or greater than zero if KEY is found to be |
2150 | less than, to match, or to be greater than the constructor_elt's INDEX. */ | |
2151 | ||
2152 | static int | |
2153 | array_index_cmp (tree key, tree index) | |
2154 | { | |
2155 | gcc_assert (TREE_CODE (key) == INTEGER_CST); | |
2156 | ||
2157 | switch (TREE_CODE (index)) | |
2158 | { | |
2159 | case INTEGER_CST: | |
2160 | return tree_int_cst_compare (key, index); | |
2161 | case RANGE_EXPR: | |
2162 | { | |
2163 | tree lo = TREE_OPERAND (index, 0); | |
2164 | tree hi = TREE_OPERAND (index, 1); | |
2165 | if (tree_int_cst_lt (key, lo)) | |
2166 | return -1; | |
2167 | else if (tree_int_cst_lt (hi, key)) | |
2168 | return 1; | |
2169 | else | |
2170 | return 0; | |
2171 | } | |
2172 | default: | |
2173 | gcc_unreachable (); | |
2174 | } | |
2175 | } | |
2176 | ||
2177 | /* Returns the index of the constructor_elt of ARY which matches DINDEX, or -1 | |
2178 | if none. If INSERT is true, insert a matching element rather than fail. */ | |
2179 | ||
2180 | static HOST_WIDE_INT | |
2181 | find_array_ctor_elt (tree ary, tree dindex, bool insert = false) | |
2182 | { | |
2183 | if (tree_int_cst_sgn (dindex) < 0) | |
2184 | return -1; | |
2185 | ||
2186 | unsigned HOST_WIDE_INT i = tree_to_uhwi (dindex); | |
2187 | vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (ary); | |
2188 | unsigned HOST_WIDE_INT len = vec_safe_length (elts); | |
2189 | ||
2190 | unsigned HOST_WIDE_INT end = len; | |
2191 | unsigned HOST_WIDE_INT begin = 0; | |
2192 | ||
2193 | /* If the last element of the CONSTRUCTOR has its own index, we can assume | |
2194 | that the same is true of the other elements and index directly. */ | |
2195 | if (end > 0) | |
2196 | { | |
e99466d6 | 2197 | tree cindex = (*elts)[end - 1].index; |
7963b19d | 2198 | if (TREE_CODE (cindex) == INTEGER_CST |
e99466d6 | 2199 | && compare_tree_int (cindex, end - 1) == 0) |
7963b19d | 2200 | { |
2201 | if (i < end) | |
2202 | return i; | |
2203 | else | |
2204 | begin = end; | |
2205 | } | |
2206 | } | |
2207 | ||
2208 | /* Otherwise, find a matching index by means of a binary search. */ | |
2209 | while (begin != end) | |
2210 | { | |
2211 | unsigned HOST_WIDE_INT middle = (begin + end) / 2; | |
f0b916c7 | 2212 | constructor_elt &elt = (*elts)[middle]; |
2213 | tree idx = elt.index; | |
7963b19d | 2214 | |
f0b916c7 | 2215 | int cmp = array_index_cmp (dindex, idx); |
7963b19d | 2216 | if (cmp < 0) |
2217 | end = middle; | |
2218 | else if (cmp > 0) | |
2219 | begin = middle + 1; | |
2220 | else | |
f0b916c7 | 2221 | { |
2222 | if (insert && TREE_CODE (idx) == RANGE_EXPR) | |
2223 | { | |
2224 | /* We need to split the range. */ | |
2225 | constructor_elt e; | |
2226 | tree lo = TREE_OPERAND (idx, 0); | |
2227 | tree hi = TREE_OPERAND (idx, 1); | |
e99466d6 | 2228 | tree value = elt.value; |
2229 | dindex = fold_convert (sizetype, dindex); | |
f0b916c7 | 2230 | if (tree_int_cst_lt (lo, dindex)) |
2231 | { | |
2232 | /* There are still some lower elts; shorten the range. */ | |
2233 | tree new_hi = int_const_binop (MINUS_EXPR, dindex, | |
2234 | size_one_node); | |
2235 | if (tree_int_cst_equal (lo, new_hi)) | |
2236 | /* Only one element left, no longer a range. */ | |
2237 | elt.index = lo; | |
2238 | else | |
2239 | TREE_OPERAND (idx, 1) = new_hi; | |
2240 | /* Append the element we want to insert. */ | |
2241 | ++middle; | |
2242 | e.index = dindex; | |
e99466d6 | 2243 | e.value = unshare_constructor (value); |
f0b916c7 | 2244 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle, e); |
2245 | } | |
2246 | else | |
2247 | /* No lower elts, the range elt is now ours. */ | |
2248 | elt.index = dindex; | |
2249 | ||
2250 | if (tree_int_cst_lt (dindex, hi)) | |
2251 | { | |
2252 | /* There are still some higher elts; append a range. */ | |
2253 | tree new_lo = int_const_binop (PLUS_EXPR, dindex, | |
2254 | size_one_node); | |
2255 | if (tree_int_cst_equal (new_lo, hi)) | |
2256 | e.index = hi; | |
2257 | else | |
2258 | e.index = build2 (RANGE_EXPR, sizetype, new_lo, hi); | |
e99466d6 | 2259 | e.value = unshare_constructor (value); |
2260 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle + 1, e); | |
f0b916c7 | 2261 | } |
2262 | } | |
2263 | return middle; | |
2264 | } | |
7963b19d | 2265 | } |
2266 | ||
2267 | if (insert) | |
2268 | { | |
2269 | constructor_elt e = { dindex, NULL_TREE }; | |
2270 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), end, e); | |
2271 | return end; | |
2272 | } | |
2273 | ||
2274 | return -1; | |
2275 | } | |
2276 | ||
40df9099 | 2277 | /* Under the control of CTX, issue a detailed diagnostic for |
2278 | an out-of-bounds subscript INDEX into the expression ARRAY. */ | |
2279 | ||
2280 | static void | |
2281 | diag_array_subscript (const constexpr_ctx *ctx, tree array, tree index) | |
2282 | { | |
2283 | if (!ctx->quiet) | |
2284 | { | |
2285 | tree arraytype = TREE_TYPE (array); | |
2286 | ||
2287 | /* Convert the unsigned array subscript to a signed integer to avoid | |
2288 | printing huge numbers for small negative values. */ | |
2289 | tree sidx = fold_convert (ssizetype, index); | |
2290 | if (DECL_P (array)) | |
2291 | { | |
d7d265db | 2292 | if (TYPE_DOMAIN (arraytype)) |
2293 | error ("array subscript value %qE is outside the bounds " | |
2294 | "of array %qD of type %qT", sidx, array, arraytype); | |
2295 | else | |
2296 | error ("non-zero array subscript %qE is used with array %qD of " | |
2297 | "type %qT with unknown bounds", sidx, array, arraytype); | |
40df9099 | 2298 | inform (DECL_SOURCE_LOCATION (array), "declared here"); |
2299 | } | |
d7d265db | 2300 | else if (TYPE_DOMAIN (arraytype)) |
40df9099 | 2301 | error ("array subscript value %qE is outside the bounds " |
2302 | "of array type %qT", sidx, arraytype); | |
d7d265db | 2303 | else |
2304 | error ("non-zero array subscript %qE is used with array of type %qT " | |
2305 | "with unknown bounds", sidx, arraytype); | |
40df9099 | 2306 | } |
2307 | } | |
7963b19d | 2308 | |
51f0c7e2 | 2309 | /* Return the number of elements for TYPE (which is an ARRAY_TYPE or |
2310 | a VECTOR_TYPE). */ | |
2311 | ||
2312 | static tree | |
2313 | get_array_or_vector_nelts (const constexpr_ctx *ctx, tree type, | |
2314 | bool *non_constant_p, bool *overflow_p) | |
2315 | { | |
2316 | tree nelts; | |
2317 | if (TREE_CODE (type) == ARRAY_TYPE) | |
2318 | { | |
2319 | if (TYPE_DOMAIN (type)) | |
2320 | nelts = array_type_nelts_top (type); | |
2321 | else | |
2322 | nelts = size_zero_node; | |
2323 | } | |
2324 | else if (VECTOR_TYPE_P (type)) | |
2325 | nelts = size_int (TYPE_VECTOR_SUBPARTS (type)); | |
2326 | else | |
2327 | gcc_unreachable (); | |
2328 | ||
2329 | /* For VLAs, the number of elements won't be an integer constant. */ | |
2330 | nelts = cxx_eval_constant_expression (ctx, nelts, false, | |
2331 | non_constant_p, overflow_p); | |
2332 | return nelts; | |
2333 | } | |
2334 | ||
92fe8840 | 2335 | /* Extract element INDEX consisting of CHARS_PER_ELT chars from |
2336 | STRING_CST STRING. */ | |
2337 | ||
2338 | static tree | |
2339 | extract_string_elt (tree string, unsigned chars_per_elt, unsigned index) | |
2340 | { | |
2341 | tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (string))); | |
2342 | tree r; | |
2343 | ||
2344 | if (chars_per_elt == 1) | |
2345 | r = build_int_cst (type, TREE_STRING_POINTER (string)[index]); | |
2346 | else | |
2347 | { | |
2348 | const unsigned char *ptr | |
2349 | = ((const unsigned char *)TREE_STRING_POINTER (string) | |
2350 | + index * chars_per_elt); | |
2351 | r = native_interpret_expr (type, ptr, chars_per_elt); | |
2352 | } | |
2353 | return r; | |
2354 | } | |
2355 | ||
09b42213 | 2356 | /* Subroutine of cxx_eval_constant_expression. |
2357 | Attempt to reduce a reference to an array slot. */ | |
2358 | ||
2359 | static tree | |
cf72f34d | 2360 | cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2361 | bool lval, |
09b42213 | 2362 | bool *non_constant_p, bool *overflow_p) |
2363 | { | |
2364 | tree oldary = TREE_OPERAND (t, 0); | |
cf72f34d | 2365 | tree ary = cxx_eval_constant_expression (ctx, oldary, |
1227ba74 | 2366 | lval, |
b2a43197 | 2367 | non_constant_p, overflow_p); |
09b42213 | 2368 | tree index, oldidx; |
cf3cefc9 | 2369 | HOST_WIDE_INT i = 0; |
2370 | tree elem_type = NULL_TREE; | |
2371 | unsigned len = 0, elem_nchars = 1; | |
09b42213 | 2372 | if (*non_constant_p) |
2373 | return t; | |
2374 | oldidx = TREE_OPERAND (t, 1); | |
cf72f34d | 2375 | index = cxx_eval_constant_expression (ctx, oldidx, |
f83e6885 | 2376 | false, |
b2a43197 | 2377 | non_constant_p, overflow_p); |
09b42213 | 2378 | VERIFY_CONSTANT (index); |
cf3cefc9 | 2379 | if (!lval) |
09b42213 | 2380 | { |
cf3cefc9 | 2381 | elem_type = TREE_TYPE (TREE_TYPE (ary)); |
2382 | if (TREE_CODE (ary) == VIEW_CONVERT_EXPR | |
2383 | && VECTOR_TYPE_P (TREE_TYPE (TREE_OPERAND (ary, 0))) | |
2384 | && TREE_TYPE (t) == TREE_TYPE (TREE_TYPE (TREE_OPERAND (ary, 0)))) | |
2385 | ary = TREE_OPERAND (ary, 0); | |
2386 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2387 | len = CONSTRUCTOR_NELTS (ary); | |
2388 | else if (TREE_CODE (ary) == STRING_CST) | |
2389 | { | |
2390 | elem_nchars = (TYPE_PRECISION (elem_type) | |
2391 | / TYPE_PRECISION (char_type_node)); | |
2392 | len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars; | |
2393 | } | |
2394 | else if (TREE_CODE (ary) == VECTOR_CST) | |
f08ee65f | 2395 | /* We don't create variable-length VECTOR_CSTs. */ |
2396 | len = VECTOR_CST_NELTS (ary).to_constant (); | |
cf3cefc9 | 2397 | else |
2398 | { | |
2399 | /* We can't do anything with other tree codes, so use | |
2400 | VERIFY_CONSTANT to complain and fail. */ | |
2401 | VERIFY_CONSTANT (ary); | |
2402 | gcc_unreachable (); | |
2403 | } | |
aed8dc7f | 2404 | |
cf3cefc9 | 2405 | if (!tree_fits_shwi_p (index) |
2406 | || (i = tree_to_shwi (index)) < 0) | |
2407 | { | |
2408 | diag_array_subscript (ctx, ary, index); | |
2409 | *non_constant_p = true; | |
2410 | return t; | |
2411 | } | |
7963b19d | 2412 | } |
2413 | ||
51f0c7e2 | 2414 | tree nelts = get_array_or_vector_nelts (ctx, TREE_TYPE (ary), non_constant_p, |
2415 | overflow_p); | |
ce6a6978 | 2416 | VERIFY_CONSTANT (nelts); |
0acc6340 | 2417 | if ((lval |
2418 | ? !tree_int_cst_le (index, nelts) | |
2419 | : !tree_int_cst_lt (index, nelts)) | |
2420 | || tree_int_cst_sgn (index) < 0) | |
ce6a6978 | 2421 | { |
40df9099 | 2422 | diag_array_subscript (ctx, ary, index); |
ce6a6978 | 2423 | *non_constant_p = true; |
2424 | return t; | |
2425 | } | |
2426 | ||
cf3cefc9 | 2427 | if (lval && ary == oldary && index == oldidx) |
2428 | return t; | |
2429 | else if (lval) | |
2430 | return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL); | |
2431 | ||
7963b19d | 2432 | bool found; |
2433 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2434 | { | |
2435 | HOST_WIDE_INT ix = find_array_ctor_elt (ary, index); | |
2436 | found = (ix >= 0); | |
2437 | if (found) | |
2438 | i = ix; | |
aed8dc7f | 2439 | } |
7963b19d | 2440 | else |
2441 | found = (i < len); | |
aed8dc7f | 2442 | |
14869f28 | 2443 | if (found) |
2444 | { | |
2445 | tree r; | |
2446 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2447 | r = (*CONSTRUCTOR_ELTS (ary))[i].value; | |
2448 | else if (TREE_CODE (ary) == VECTOR_CST) | |
2449 | r = VECTOR_CST_ELT (ary, i); | |
14869f28 | 2450 | else |
92fe8840 | 2451 | r = extract_string_elt (ary, elem_nchars, i); |
2452 | ||
14869f28 | 2453 | if (r) |
2454 | /* Don't VERIFY_CONSTANT here. */ | |
2455 | return r; | |
09b42213 | 2456 | |
14869f28 | 2457 | /* Otherwise the element doesn't have a value yet. */ |
09b42213 | 2458 | } |
aed8dc7f | 2459 | |
14869f28 | 2460 | /* Not found. */ |
2461 | ||
2462 | if (TREE_CODE (ary) == CONSTRUCTOR | |
2463 | && CONSTRUCTOR_NO_IMPLICIT_ZERO (ary)) | |
09b42213 | 2464 | { |
14869f28 | 2465 | /* 'ary' is part of the aggregate initializer we're currently |
2466 | building; if there's no initializer for this element yet, | |
2467 | that's an error. */ | |
2468 | if (!ctx->quiet) | |
2469 | error ("accessing uninitialized array element"); | |
2470 | *non_constant_p = true; | |
2471 | return t; | |
09b42213 | 2472 | } |
14869f28 | 2473 | |
2474 | /* If it's within the array bounds but doesn't have an explicit | |
2475 | initializer, it's value-initialized. */ | |
2476 | tree val = build_value_init (elem_type, tf_warning_or_error); | |
2477 | return cxx_eval_constant_expression (ctx, val, lval, non_constant_p, | |
2478 | overflow_p); | |
09b42213 | 2479 | } |
2480 | ||
2481 | /* Subroutine of cxx_eval_constant_expression. | |
2482 | Attempt to reduce a field access of a value of class type. */ | |
2483 | ||
2484 | static tree | |
cf72f34d | 2485 | cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2486 | bool lval, |
09b42213 | 2487 | bool *non_constant_p, bool *overflow_p) |
2488 | { | |
2489 | unsigned HOST_WIDE_INT i; | |
2490 | tree field; | |
2491 | tree value; | |
2492 | tree part = TREE_OPERAND (t, 1); | |
2493 | tree orig_whole = TREE_OPERAND (t, 0); | |
cf72f34d | 2494 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2495 | lval, |
b2a43197 | 2496 | non_constant_p, overflow_p); |
7ab20d7c | 2497 | if (INDIRECT_REF_P (whole) |
cb768824 | 2498 | && integer_zerop (TREE_OPERAND (whole, 0)) |
2499 | && !ctx->quiet) | |
2500 | error ("dereferencing a null pointer in %qE", orig_whole); | |
2501 | ||
f16ed232 | 2502 | if (TREE_CODE (whole) == PTRMEM_CST) |
2503 | whole = cplus_expand_constant (whole); | |
09b42213 | 2504 | if (whole == orig_whole) |
2505 | return t; | |
1227ba74 | 2506 | if (lval) |
09b42213 | 2507 | return fold_build3 (COMPONENT_REF, TREE_TYPE (t), |
2508 | whole, part, NULL_TREE); | |
2509 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2510 | CONSTRUCTOR. */ | |
2511 | if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR) | |
2512 | { | |
f83e6885 | 2513 | if (!ctx->quiet) |
09b42213 | 2514 | error ("%qE is not a constant expression", orig_whole); |
2515 | *non_constant_p = true; | |
2516 | } | |
2517 | if (DECL_MUTABLE_P (part)) | |
2518 | { | |
f83e6885 | 2519 | if (!ctx->quiet) |
09b42213 | 2520 | error ("mutable %qD is not usable in a constant expression", part); |
2521 | *non_constant_p = true; | |
2522 | } | |
2523 | if (*non_constant_p) | |
2524 | return t; | |
a4360e57 | 2525 | bool pmf = TYPE_PTRMEMFUNC_P (TREE_TYPE (whole)); |
09b42213 | 2526 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) |
2527 | { | |
a4360e57 | 2528 | /* Use name match for PMF fields, as a variant will have a |
2529 | different FIELD_DECL with a different type. */ | |
2530 | if (pmf ? DECL_NAME (field) == DECL_NAME (part) | |
2531 | : field == part) | |
9c96033c | 2532 | { |
2533 | if (value) | |
2534 | return value; | |
2535 | else | |
2536 | /* We're in the middle of initializing it. */ | |
2537 | break; | |
2538 | } | |
09b42213 | 2539 | } |
2540 | if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE | |
2541 | && CONSTRUCTOR_NELTS (whole) > 0) | |
2542 | { | |
2543 | /* DR 1188 says we don't have to deal with this. */ | |
f83e6885 | 2544 | if (!ctx->quiet) |
09b42213 | 2545 | error ("accessing %qD member instead of initialized %qD member in " |
2546 | "constant expression", part, CONSTRUCTOR_ELT (whole, 0)->index); | |
2547 | *non_constant_p = true; | |
2548 | return t; | |
2549 | } | |
2550 | ||
f894a056 | 2551 | /* We only create a CONSTRUCTOR for a subobject when we modify it, so empty |
2552 | classes never get represented; throw together a value now. */ | |
2553 | if (is_really_empty_class (TREE_TYPE (t))) | |
2554 | return build_constructor (TREE_TYPE (t), NULL); | |
2555 | ||
a4360e57 | 2556 | gcc_assert (DECL_CONTEXT (part) == TYPE_MAIN_VARIANT (TREE_TYPE (whole))); |
2557 | ||
f894a056 | 2558 | if (CONSTRUCTOR_NO_IMPLICIT_ZERO (whole)) |
cf72f34d | 2559 | { |
2560 | /* 'whole' is part of the aggregate initializer we're currently | |
2561 | building; if there's no initializer for this member yet, that's an | |
f894a056 | 2562 | error. */ |
f83e6885 | 2563 | if (!ctx->quiet) |
cf72f34d | 2564 | error ("accessing uninitialized member %qD", part); |
2565 | *non_constant_p = true; | |
2566 | return t; | |
2567 | } | |
2568 | ||
09b42213 | 2569 | /* If there's no explicit init for this field, it's value-initialized. */ |
2570 | value = build_value_init (TREE_TYPE (t), tf_warning_or_error); | |
cf72f34d | 2571 | return cxx_eval_constant_expression (ctx, value, |
1227ba74 | 2572 | lval, |
b2a43197 | 2573 | non_constant_p, overflow_p); |
09b42213 | 2574 | } |
2575 | ||
2576 | /* Subroutine of cxx_eval_constant_expression. | |
2577 | Attempt to reduce a field access of a value of class type that is | |
2578 | expressed as a BIT_FIELD_REF. */ | |
2579 | ||
2580 | static tree | |
cf72f34d | 2581 | cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2582 | bool lval, |
09b42213 | 2583 | bool *non_constant_p, bool *overflow_p) |
2584 | { | |
2585 | tree orig_whole = TREE_OPERAND (t, 0); | |
2586 | tree retval, fldval, utype, mask; | |
2587 | bool fld_seen = false; | |
2588 | HOST_WIDE_INT istart, isize; | |
cf72f34d | 2589 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2590 | lval, |
b2a43197 | 2591 | non_constant_p, overflow_p); |
09b42213 | 2592 | tree start, field, value; |
2593 | unsigned HOST_WIDE_INT i; | |
2594 | ||
2595 | if (whole == orig_whole) | |
2596 | return t; | |
2597 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2598 | CONSTRUCTOR. */ | |
2599 | if (!*non_constant_p | |
2600 | && TREE_CODE (whole) != VECTOR_CST | |
2601 | && TREE_CODE (whole) != CONSTRUCTOR) | |
2602 | { | |
f83e6885 | 2603 | if (!ctx->quiet) |
09b42213 | 2604 | error ("%qE is not a constant expression", orig_whole); |
2605 | *non_constant_p = true; | |
2606 | } | |
2607 | if (*non_constant_p) | |
2608 | return t; | |
2609 | ||
2610 | if (TREE_CODE (whole) == VECTOR_CST) | |
2611 | return fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole, | |
2612 | TREE_OPERAND (t, 1), TREE_OPERAND (t, 2)); | |
2613 | ||
2614 | start = TREE_OPERAND (t, 2); | |
2615 | istart = tree_to_shwi (start); | |
2616 | isize = tree_to_shwi (TREE_OPERAND (t, 1)); | |
2617 | utype = TREE_TYPE (t); | |
2618 | if (!TYPE_UNSIGNED (utype)) | |
2619 | utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1); | |
2620 | retval = build_int_cst (utype, 0); | |
2621 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
2622 | { | |
2623 | tree bitpos = bit_position (field); | |
2624 | if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1)) | |
2625 | return value; | |
2626 | if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE | |
2627 | && TREE_CODE (value) == INTEGER_CST | |
2628 | && tree_fits_shwi_p (bitpos) | |
2629 | && tree_fits_shwi_p (DECL_SIZE (field))) | |
2630 | { | |
2631 | HOST_WIDE_INT bit = tree_to_shwi (bitpos); | |
2632 | HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field)); | |
2633 | HOST_WIDE_INT shift; | |
2634 | if (bit >= istart && bit + sz <= istart + isize) | |
2635 | { | |
2636 | fldval = fold_convert (utype, value); | |
2637 | mask = build_int_cst_type (utype, -1); | |
2638 | mask = fold_build2 (LSHIFT_EXPR, utype, mask, | |
2639 | size_int (TYPE_PRECISION (utype) - sz)); | |
2640 | mask = fold_build2 (RSHIFT_EXPR, utype, mask, | |
2641 | size_int (TYPE_PRECISION (utype) - sz)); | |
2642 | fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask); | |
2643 | shift = bit - istart; | |
2644 | if (BYTES_BIG_ENDIAN) | |
2645 | shift = TYPE_PRECISION (utype) - shift - sz; | |
2646 | fldval = fold_build2 (LSHIFT_EXPR, utype, fldval, | |
2647 | size_int (shift)); | |
2648 | retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval); | |
2649 | fld_seen = true; | |
2650 | } | |
2651 | } | |
2652 | } | |
2653 | if (fld_seen) | |
2654 | return fold_convert (TREE_TYPE (t), retval); | |
2655 | gcc_unreachable (); | |
2656 | return error_mark_node; | |
2657 | } | |
2658 | ||
2659 | /* Subroutine of cxx_eval_constant_expression. | |
2660 | Evaluate a short-circuited logical expression T in the context | |
2661 | of a given constexpr CALL. BAILOUT_VALUE is the value for | |
2662 | early return. CONTINUE_VALUE is used here purely for | |
2663 | sanity check purposes. */ | |
2664 | ||
2665 | static tree | |
cf72f34d | 2666 | cxx_eval_logical_expression (const constexpr_ctx *ctx, tree t, |
09b42213 | 2667 | tree bailout_value, tree continue_value, |
1227ba74 | 2668 | bool lval, |
09b42213 | 2669 | bool *non_constant_p, bool *overflow_p) |
2670 | { | |
2671 | tree r; | |
cf72f34d | 2672 | tree lhs = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 2673 | lval, |
b2a43197 | 2674 | non_constant_p, overflow_p); |
09b42213 | 2675 | VERIFY_CONSTANT (lhs); |
2676 | if (tree_int_cst_equal (lhs, bailout_value)) | |
2677 | return lhs; | |
2678 | gcc_assert (tree_int_cst_equal (lhs, continue_value)); | |
cf72f34d | 2679 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2680 | lval, non_constant_p, |
b2a43197 | 2681 | overflow_p); |
09b42213 | 2682 | VERIFY_CONSTANT (r); |
2683 | return r; | |
2684 | } | |
2685 | ||
2686 | /* REF is a COMPONENT_REF designating a particular field. V is a vector of | |
2687 | CONSTRUCTOR elements to initialize (part of) an object containing that | |
2688 | field. Return a pointer to the constructor_elt corresponding to the | |
2689 | initialization of the field. */ | |
2690 | ||
2691 | static constructor_elt * | |
2692 | base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref) | |
2693 | { | |
2694 | tree aggr = TREE_OPERAND (ref, 0); | |
2695 | tree field = TREE_OPERAND (ref, 1); | |
2696 | HOST_WIDE_INT i; | |
2697 | constructor_elt *ce; | |
2698 | ||
2699 | gcc_assert (TREE_CODE (ref) == COMPONENT_REF); | |
2700 | ||
2701 | if (TREE_CODE (aggr) == COMPONENT_REF) | |
2702 | { | |
2703 | constructor_elt *base_ce | |
2704 | = base_field_constructor_elt (v, aggr); | |
2705 | v = CONSTRUCTOR_ELTS (base_ce->value); | |
2706 | } | |
2707 | ||
2708 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2709 | if (ce->index == field) | |
2710 | return ce; | |
2711 | ||
2712 | gcc_unreachable (); | |
2713 | return NULL; | |
2714 | } | |
2715 | ||
cf72f34d | 2716 | /* Some of the expressions fed to the constexpr mechanism are calls to |
2717 | constructors, which have type void. In that case, return the type being | |
2718 | initialized by the constructor. */ | |
2719 | ||
2720 | static tree | |
2721 | initialized_type (tree t) | |
2722 | { | |
2723 | if (TYPE_P (t)) | |
2724 | return t; | |
2725 | tree type = cv_unqualified (TREE_TYPE (t)); | |
2726 | if (TREE_CODE (t) == CALL_EXPR || TREE_CODE (t) == AGGR_INIT_EXPR) | |
2727 | { | |
2728 | /* A constructor call has void type, so we need to look deeper. */ | |
2729 | tree fn = get_function_named_in_call (t); | |
2730 | if (fn && TREE_CODE (fn) == FUNCTION_DECL | |
2731 | && DECL_CXX_CONSTRUCTOR_P (fn)) | |
2732 | type = DECL_CONTEXT (fn); | |
2733 | } | |
2734 | return type; | |
2735 | } | |
2736 | ||
2737 | /* We're about to initialize element INDEX of an array or class from VALUE. | |
2738 | Set up NEW_CTX appropriately by adjusting .object to refer to the | |
2739 | subobject and creating a new CONSTRUCTOR if the element is itself | |
2740 | a class or array. */ | |
2741 | ||
2742 | static void | |
2743 | init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, | |
2744 | tree index, tree &value) | |
2745 | { | |
2746 | new_ctx = *ctx; | |
2747 | ||
2748 | if (index && TREE_CODE (index) != INTEGER_CST | |
2749 | && TREE_CODE (index) != FIELD_DECL) | |
2750 | /* This won't have an element in the new CONSTRUCTOR. */ | |
2751 | return; | |
2752 | ||
2753 | tree type = initialized_type (value); | |
2754 | if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) | |
2755 | /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ | |
2756 | return; | |
2757 | ||
2758 | /* The sub-aggregate initializer might contain a placeholder; | |
2759 | update object to refer to the subobject and ctor to refer to | |
2760 | the (newly created) sub-initializer. */ | |
2761 | if (ctx->object) | |
2762 | new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); | |
2763 | tree elt = build_constructor (type, NULL); | |
2764 | CONSTRUCTOR_NO_IMPLICIT_ZERO (elt) = true; | |
2765 | new_ctx.ctor = elt; | |
2766 | ||
2767 | if (TREE_CODE (value) == TARGET_EXPR) | |
2768 | /* Avoid creating another CONSTRUCTOR when we expand the TARGET_EXPR. */ | |
2769 | value = TARGET_EXPR_INITIAL (value); | |
2770 | } | |
2771 | ||
2772 | /* We're about to process an initializer for a class or array TYPE. Make | |
2773 | sure that CTX is set up appropriately. */ | |
2774 | ||
2775 | static void | |
2776 | verify_ctor_sanity (const constexpr_ctx *ctx, tree type) | |
2777 | { | |
2778 | /* We don't bother building a ctor for an empty base subobject. */ | |
2779 | if (is_empty_class (type)) | |
2780 | return; | |
2781 | ||
2782 | /* We're in the middle of an initializer that might involve placeholders; | |
2783 | our caller should have created a CONSTRUCTOR for us to put the | |
2784 | initializer into. We will either return that constructor or T. */ | |
2785 | gcc_assert (ctx->ctor); | |
2786 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2787 | (type, TREE_TYPE (ctx->ctor))); | |
bbf58224 | 2788 | /* We used to check that ctx->ctor was empty, but that isn't the case when |
2789 | the object is zero-initialized before calling the constructor. */ | |
cf72f34d | 2790 | if (ctx->object) |
d9751a3c | 2791 | { |
2792 | tree otype = TREE_TYPE (ctx->object); | |
2793 | gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, otype) | |
2794 | /* Handle flexible array members. */ | |
2795 | || (TREE_CODE (otype) == ARRAY_TYPE | |
2796 | && TYPE_DOMAIN (otype) == NULL_TREE | |
2797 | && TREE_CODE (type) == ARRAY_TYPE | |
2798 | && (same_type_ignoring_top_level_qualifiers_p | |
2799 | (TREE_TYPE (type), TREE_TYPE (otype))))); | |
2800 | } | |
cf72f34d | 2801 | gcc_assert (!ctx->object || !DECL_P (ctx->object) |
2802 | || *(ctx->values->get (ctx->object)) == ctx->ctor); | |
2803 | } | |
2804 | ||
09b42213 | 2805 | /* Subroutine of cxx_eval_constant_expression. |
2806 | The expression tree T denotes a C-style array or a C-style | |
2807 | aggregate. Reduce it to a constant expression. */ | |
2808 | ||
2809 | static tree | |
cf72f34d | 2810 | cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2811 | bool lval, |
09b42213 | 2812 | bool *non_constant_p, bool *overflow_p) |
2813 | { | |
2814 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
09b42213 | 2815 | bool changed = false; |
2816 | gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t)); | |
68464393 | 2817 | tree type = TREE_TYPE (t); |
cf72f34d | 2818 | |
68464393 | 2819 | constexpr_ctx new_ctx; |
d2dd85e3 | 2820 | if (TYPE_PTRMEMFUNC_P (type) || VECTOR_TYPE_P (type)) |
68464393 | 2821 | { |
d2dd85e3 | 2822 | /* We don't really need the ctx->ctor business for a PMF or |
2823 | vector, but it's simpler to use the same code. */ | |
68464393 | 2824 | new_ctx = *ctx; |
2825 | new_ctx.ctor = build_constructor (type, NULL); | |
2826 | new_ctx.object = NULL_TREE; | |
2827 | ctx = &new_ctx; | |
2828 | }; | |
2829 | verify_ctor_sanity (ctx, type); | |
cf72f34d | 2830 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); |
2831 | vec_alloc (*p, vec_safe_length (v)); | |
2832 | ||
58b0f9ce | 2833 | unsigned i; |
2834 | tree index, value; | |
2835 | bool constant_p = true; | |
2836 | bool side_effects_p = false; | |
cf72f34d | 2837 | FOR_EACH_CONSTRUCTOR_ELT (v, i, index, value) |
09b42213 | 2838 | { |
5ae773e4 | 2839 | tree orig_value = value; |
cf72f34d | 2840 | init_subob_ctx (ctx, new_ctx, index, value); |
2841 | if (new_ctx.ctor != ctx->ctor) | |
2842 | /* If we built a new CONSTRUCTOR, attach it now so that other | |
2843 | initializers can refer to it. */ | |
2844 | CONSTRUCTOR_APPEND_ELT (*p, index, new_ctx.ctor); | |
2845 | tree elt = cxx_eval_constant_expression (&new_ctx, value, | |
1227ba74 | 2846 | lval, |
b2a43197 | 2847 | non_constant_p, overflow_p); |
09b42213 | 2848 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 2849 | if (ctx->quiet && *non_constant_p) |
cf72f34d | 2850 | break; |
5ae773e4 | 2851 | if (elt != orig_value) |
09b42213 | 2852 | changed = true; |
58b0f9ce | 2853 | |
2854 | if (!TREE_CONSTANT (elt)) | |
2855 | constant_p = false; | |
2856 | if (TREE_SIDE_EFFECTS (elt)) | |
2857 | side_effects_p = true; | |
cf72f34d | 2858 | if (index && TREE_CODE (index) == COMPONENT_REF) |
09b42213 | 2859 | { |
2860 | /* This is an initialization of a vfield inside a base | |
2861 | subaggregate that we already initialized; push this | |
2862 | initialization into the previous initialization. */ | |
cf72f34d | 2863 | constructor_elt *inner = base_field_constructor_elt (*p, index); |
09b42213 | 2864 | inner->value = elt; |
cf72f34d | 2865 | changed = true; |
09b42213 | 2866 | } |
cf72f34d | 2867 | else if (index |
2868 | && (TREE_CODE (index) == NOP_EXPR | |
2869 | || TREE_CODE (index) == POINTER_PLUS_EXPR)) | |
09b42213 | 2870 | { |
2871 | /* This is an initializer for an empty base; now that we've | |
2872 | checked that it's constant, we can ignore it. */ | |
cf72f34d | 2873 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (index)))); |
2874 | changed = true; | |
2875 | } | |
09b42213 | 2876 | else |
79e65a6b | 2877 | { |
0dd49b5a | 2878 | if (new_ctx.ctor != ctx->ctor) |
2879 | { | |
2880 | /* We appended this element above; update the value. */ | |
2881 | gcc_assert ((*p)->last().index == index); | |
2882 | (*p)->last().value = elt; | |
2883 | } | |
2884 | else | |
2885 | CONSTRUCTOR_APPEND_ELT (*p, index, elt); | |
2886 | /* Adding or replacing an element might change the ctor's flags. */ | |
79e65a6b | 2887 | TREE_CONSTANT (ctx->ctor) = constant_p; |
2888 | TREE_SIDE_EFFECTS (ctx->ctor) = side_effects_p; | |
2889 | } | |
09b42213 | 2890 | } |
2891 | if (*non_constant_p || !changed) | |
cf72f34d | 2892 | return t; |
2893 | t = ctx->ctor; | |
2894 | /* We're done building this CONSTRUCTOR, so now we can interpret an | |
2895 | element without an explicit initializer as value-initialized. */ | |
2896 | CONSTRUCTOR_NO_IMPLICIT_ZERO (t) = false; | |
58b0f9ce | 2897 | TREE_CONSTANT (t) = constant_p; |
2898 | TREE_SIDE_EFFECTS (t) = side_effects_p; | |
68464393 | 2899 | if (VECTOR_TYPE_P (type)) |
09b42213 | 2900 | t = fold (t); |
2901 | return t; | |
2902 | } | |
2903 | ||
2904 | /* Subroutine of cxx_eval_constant_expression. | |
2905 | The expression tree T is a VEC_INIT_EXPR which denotes the desired | |
2906 | initialization of a non-static data member of array type. Reduce it to a | |
2907 | CONSTRUCTOR. | |
2908 | ||
2909 | Note that apart from value-initialization (when VALUE_INIT is true), | |
2910 | this is only intended to support value-initialization and the | |
2911 | initializations done by defaulted constructors for classes with | |
2912 | non-static data members of array type. In this case, VEC_INIT_EXPR_INIT | |
2913 | will either be NULL_TREE for the default constructor, or a COMPONENT_REF | |
2914 | for the copy/move constructor. */ | |
2915 | ||
2916 | static tree | |
cf72f34d | 2917 | cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, |
1227ba74 | 2918 | bool value_init, bool lval, |
09b42213 | 2919 | bool *non_constant_p, bool *overflow_p) |
2920 | { | |
2921 | tree elttype = TREE_TYPE (atype); | |
cf72f34d | 2922 | verify_ctor_sanity (ctx, atype); |
2923 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
09b42213 | 2924 | bool pre_init = false; |
3e520b97 | 2925 | unsigned HOST_WIDE_INT i; |
09b42213 | 2926 | |
2927 | /* For the default constructor, build up a call to the default | |
2928 | constructor of the element type. We only need to handle class types | |
2929 | here, as for a constructor to be constexpr, all members must be | |
2930 | initialized, which for a defaulted default constructor means they must | |
2931 | be of a class type with a constexpr default constructor. */ | |
2932 | if (TREE_CODE (elttype) == ARRAY_TYPE) | |
2933 | /* We only do this at the lowest level. */; | |
2934 | else if (value_init) | |
2935 | { | |
2936 | init = build_value_init (elttype, tf_warning_or_error); | |
09b42213 | 2937 | pre_init = true; |
2938 | } | |
2939 | else if (!init) | |
2940 | { | |
2941 | vec<tree, va_gc> *argvec = make_tree_vector (); | |
2942 | init = build_special_member_call (NULL_TREE, complete_ctor_identifier, | |
2943 | &argvec, elttype, LOOKUP_NORMAL, | |
2944 | tf_warning_or_error); | |
2945 | release_tree_vector (argvec); | |
9c96033c | 2946 | init = build_aggr_init_expr (TREE_TYPE (init), init); |
09b42213 | 2947 | pre_init = true; |
2948 | } | |
2949 | ||
51f0c7e2 | 2950 | tree nelts = get_array_or_vector_nelts (ctx, atype, non_constant_p, |
2951 | overflow_p); | |
2952 | unsigned HOST_WIDE_INT max = tree_to_uhwi (nelts); | |
3e520b97 | 2953 | for (i = 0; i < max; ++i) |
09b42213 | 2954 | { |
2955 | tree idx = build_int_cst (size_type_node, i); | |
2956 | tree eltinit; | |
d9377ad5 | 2957 | bool reuse = false; |
cf72f34d | 2958 | constexpr_ctx new_ctx; |
2959 | init_subob_ctx (ctx, new_ctx, idx, pre_init ? init : elttype); | |
2960 | if (new_ctx.ctor != ctx->ctor) | |
2961 | CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor); | |
09b42213 | 2962 | if (TREE_CODE (elttype) == ARRAY_TYPE) |
2963 | { | |
2964 | /* A multidimensional array; recurse. */ | |
2965 | if (value_init || init == NULL_TREE) | |
d9377ad5 | 2966 | { |
2967 | eltinit = NULL_TREE; | |
2968 | reuse = i == 0; | |
2969 | } | |
09b42213 | 2970 | else |
2971 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2972 | tf_warning_or_error); | |
cf72f34d | 2973 | eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, value_init, |
1227ba74 | 2974 | lval, |
09b42213 | 2975 | non_constant_p, overflow_p); |
2976 | } | |
2977 | else if (pre_init) | |
2978 | { | |
2979 | /* Initializing an element using value or default initialization | |
2980 | we just pre-built above. */ | |
d9377ad5 | 2981 | eltinit = cxx_eval_constant_expression (&new_ctx, init, lval, |
2982 | non_constant_p, overflow_p); | |
2983 | reuse = i == 0; | |
09b42213 | 2984 | } |
2985 | else | |
2986 | { | |
2987 | /* Copying an element. */ | |
2988 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2989 | (atype, TREE_TYPE (init))); | |
2990 | eltinit = cp_build_array_ref (input_location, init, idx, | |
2991 | tf_warning_or_error); | |
18bede74 | 2992 | if (!lvalue_p (init)) |
09b42213 | 2993 | eltinit = move (eltinit); |
2994 | eltinit = force_rvalue (eltinit, tf_warning_or_error); | |
eb7c25cc | 2995 | eltinit = cxx_eval_constant_expression (&new_ctx, eltinit, lval, |
2996 | non_constant_p, overflow_p); | |
09b42213 | 2997 | } |
f83e6885 | 2998 | if (*non_constant_p && !ctx->quiet) |
cf72f34d | 2999 | break; |
3000 | if (new_ctx.ctor != ctx->ctor) | |
3001 | { | |
3002 | /* We appended this element above; update the value. */ | |
3003 | gcc_assert ((*p)->last().index == idx); | |
3004 | (*p)->last().value = eltinit; | |
3005 | } | |
3006 | else | |
3007 | CONSTRUCTOR_APPEND_ELT (*p, idx, eltinit); | |
d9377ad5 | 3008 | /* Reuse the result of cxx_eval_constant_expression call |
eb7c25cc | 3009 | from the first iteration to all others if it is a constant |
3010 | initializer that doesn't require relocations. */ | |
d9377ad5 | 3011 | if (reuse |
3012 | && max > 1 | |
eb7c25cc | 3013 | && (eltinit == NULL_TREE |
3014 | || (initializer_constant_valid_p (eltinit, TREE_TYPE (eltinit)) | |
3015 | == null_pointer_node))) | |
d9377ad5 | 3016 | { |
3017 | if (new_ctx.ctor != ctx->ctor) | |
3018 | eltinit = new_ctx.ctor; | |
228a2cd8 | 3019 | tree range = build2 (RANGE_EXPR, size_type_node, |
3020 | build_int_cst (size_type_node, 1), | |
3021 | build_int_cst (size_type_node, max - 1)); | |
3022 | CONSTRUCTOR_APPEND_ELT (*p, range, unshare_constructor (eltinit)); | |
d9377ad5 | 3023 | break; |
3024 | } | |
228a2cd8 | 3025 | else if (i == 0) |
3026 | vec_safe_reserve (*p, max); | |
09b42213 | 3027 | } |
3028 | ||
3029 | if (!*non_constant_p) | |
3030 | { | |
cf72f34d | 3031 | init = ctx->ctor; |
3032 | CONSTRUCTOR_NO_IMPLICIT_ZERO (init) = false; | |
09b42213 | 3033 | } |
09b42213 | 3034 | return init; |
3035 | } | |
3036 | ||
3037 | static tree | |
cf72f34d | 3038 | cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3039 | bool lval, |
09b42213 | 3040 | bool *non_constant_p, bool *overflow_p) |
3041 | { | |
3042 | tree atype = TREE_TYPE (t); | |
3043 | tree init = VEC_INIT_EXPR_INIT (t); | |
cf72f34d | 3044 | tree r = cxx_eval_vec_init_1 (ctx, atype, init, |
09b42213 | 3045 | VEC_INIT_EXPR_VALUE_INIT (t), |
1227ba74 | 3046 | lval, non_constant_p, overflow_p); |
09b42213 | 3047 | if (*non_constant_p) |
3048 | return t; | |
3049 | else | |
3050 | return r; | |
3051 | } | |
3052 | ||
3053 | /* A less strict version of fold_indirect_ref_1, which requires cv-quals to | |
3054 | match. We want to be less strict for simple *& folding; if we have a | |
3055 | non-const temporary that we access through a const pointer, that should | |
3056 | work. We handle this here rather than change fold_indirect_ref_1 | |
3057 | because we're dealing with things like ADDR_EXPR of INTEGER_CST which | |
3058 | don't really make sense outside of constant expression evaluation. Also | |
3059 | we want to allow folding to COMPONENT_REF, which could cause trouble | |
3060 | with TBAA in fold_indirect_ref_1. | |
3061 | ||
3062 | Try to keep this function synced with fold_indirect_ref_1. */ | |
3063 | ||
3064 | static tree | |
3065 | cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) | |
3066 | { | |
7d8e655d | 3067 | tree sub = op0; |
3068 | tree subtype; | |
3069 | poly_uint64 const_op01; | |
09b42213 | 3070 | |
09b42213 | 3071 | STRIP_NOPS (sub); |
3072 | subtype = TREE_TYPE (sub); | |
3073 | if (!POINTER_TYPE_P (subtype)) | |
3074 | return NULL_TREE; | |
3075 | ||
3076 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3077 | { | |
3078 | tree op = TREE_OPERAND (sub, 0); | |
3079 | tree optype = TREE_TYPE (op); | |
3080 | ||
3081 | /* *&CONST_DECL -> to the value of the const decl. */ | |
3082 | if (TREE_CODE (op) == CONST_DECL) | |
3083 | return DECL_INITIAL (op); | |
3084 | /* *&p => p; make sure to handle *&"str"[cst] here. */ | |
c4118b0c | 3085 | if (same_type_ignoring_top_level_qualifiers_p (optype, type) |
3086 | /* Also handle the case where the desired type is an array of unknown | |
3087 | bounds because the variable has had its bounds deduced since the | |
3088 | ADDR_EXPR was created. */ | |
3089 | || (TREE_CODE (type) == ARRAY_TYPE | |
3090 | && TREE_CODE (optype) == ARRAY_TYPE | |
3091 | && TYPE_DOMAIN (type) == NULL_TREE | |
3092 | && same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (optype), | |
3093 | TREE_TYPE (type)))) | |
09b42213 | 3094 | { |
3095 | tree fop = fold_read_from_constant_string (op); | |
3096 | if (fop) | |
3097 | return fop; | |
3098 | else | |
3099 | return op; | |
3100 | } | |
3101 | /* *(foo *)&fooarray => fooarray[0] */ | |
3102 | else if (TREE_CODE (optype) == ARRAY_TYPE | |
3103 | && (same_type_ignoring_top_level_qualifiers_p | |
3104 | (type, TREE_TYPE (optype)))) | |
3105 | { | |
3106 | tree type_domain = TYPE_DOMAIN (optype); | |
3107 | tree min_val = size_zero_node; | |
3108 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3109 | min_val = TYPE_MIN_VALUE (type_domain); | |
3110 | return build4_loc (loc, ARRAY_REF, type, op, min_val, | |
3111 | NULL_TREE, NULL_TREE); | |
3112 | } | |
3113 | /* *(foo *)&complexfoo => __real__ complexfoo */ | |
3114 | else if (TREE_CODE (optype) == COMPLEX_TYPE | |
3115 | && (same_type_ignoring_top_level_qualifiers_p | |
3116 | (type, TREE_TYPE (optype)))) | |
3117 | return fold_build1_loc (loc, REALPART_EXPR, type, op); | |
3118 | /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3119 | else if (VECTOR_TYPE_P (optype) |
09b42213 | 3120 | && (same_type_ignoring_top_level_qualifiers_p |
3121 | (type, TREE_TYPE (optype)))) | |
3122 | { | |
3123 | tree part_width = TYPE_SIZE (type); | |
3124 | tree index = bitsize_int (0); | |
7d8e655d | 3125 | return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, |
3126 | index); | |
09b42213 | 3127 | } |
3128 | /* Also handle conversion to an empty base class, which | |
3129 | is represented with a NOP_EXPR. */ | |
3130 | else if (is_empty_class (type) | |
3131 | && CLASS_TYPE_P (optype) | |
3132 | && DERIVED_FROM_P (type, optype)) | |
3133 | { | |
3134 | *empty_base = true; | |
3135 | return op; | |
3136 | } | |
3137 | /* *(foo *)&struct_with_foo_field => COMPONENT_REF */ | |
3138 | else if (RECORD_OR_UNION_TYPE_P (optype)) | |
3139 | { | |
3140 | tree field = TYPE_FIELDS (optype); | |
3141 | for (; field; field = DECL_CHAIN (field)) | |
3142 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3143 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3144 | && integer_zerop (byte_position (field)) |
3145 | && (same_type_ignoring_top_level_qualifiers_p | |
3146 | (TREE_TYPE (field), type))) | |
a48667ee | 3147 | return fold_build3 (COMPONENT_REF, type, op, field, NULL_TREE); |
09b42213 | 3148 | } |
3149 | } | |
3150 | else if (TREE_CODE (sub) == POINTER_PLUS_EXPR | |
7d8e655d | 3151 | && poly_int_tree_p (TREE_OPERAND (sub, 1), &const_op01)) |
09b42213 | 3152 | { |
3153 | tree op00 = TREE_OPERAND (sub, 0); | |
3154 | tree op01 = TREE_OPERAND (sub, 1); | |
3155 | ||
3156 | STRIP_NOPS (op00); | |
3157 | if (TREE_CODE (op00) == ADDR_EXPR) | |
3158 | { | |
3159 | tree op00type; | |
3160 | op00 = TREE_OPERAND (op00, 0); | |
3161 | op00type = TREE_TYPE (op00); | |
3162 | ||
3163 | /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3164 | if (VECTOR_TYPE_P (op00type) |
7d8e655d | 3165 | && same_type_ignoring_top_level_qualifiers_p |
3166 | (type, TREE_TYPE (op00type)) | |
3167 | /* POINTER_PLUS_EXPR second operand is sizetype, unsigned, | |
3168 | but we want to treat offsets with MSB set as negative. | |
3169 | For the code below negative offsets are invalid and | |
3170 | TYPE_SIZE of the element is something unsigned, so | |
3171 | check whether op01 fits into poly_int64, which implies | |
3172 | it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and | |
3173 | then just use poly_uint64 because we want to treat the | |
3174 | value as unsigned. */ | |
3175 | && tree_fits_poly_int64_p (op01)) | |
09b42213 | 3176 | { |
09b42213 | 3177 | tree part_width = TYPE_SIZE (type); |
7d8e655d | 3178 | poly_uint64 max_offset |
3179 | = (tree_to_uhwi (part_width) / BITS_PER_UNIT | |
3180 | * TYPE_VECTOR_SUBPARTS (op00type)); | |
3181 | if (known_lt (const_op01, max_offset)) | |
3182 | { | |
3183 | tree index = bitsize_int (const_op01 * BITS_PER_UNIT); | |
3184 | return fold_build3_loc (loc, | |
3185 | BIT_FIELD_REF, type, op00, | |
3186 | part_width, index); | |
3187 | } | |
09b42213 | 3188 | } |
3189 | /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ | |
3190 | else if (TREE_CODE (op00type) == COMPLEX_TYPE | |
3191 | && (same_type_ignoring_top_level_qualifiers_p | |
3192 | (type, TREE_TYPE (op00type)))) | |
3193 | { | |
7d8e655d | 3194 | if (known_eq (wi::to_poly_offset (TYPE_SIZE_UNIT (type)), |
3195 | const_op01)) | |
09b42213 | 3196 | return fold_build1_loc (loc, IMAGPART_EXPR, type, op00); |
3197 | } | |
3198 | /* ((foo *)&fooarray)[1] => fooarray[1] */ | |
3199 | else if (TREE_CODE (op00type) == ARRAY_TYPE | |
3200 | && (same_type_ignoring_top_level_qualifiers_p | |
3201 | (type, TREE_TYPE (op00type)))) | |
3202 | { | |
3203 | tree type_domain = TYPE_DOMAIN (op00type); | |
3204 | tree min_val = size_zero_node; | |
3205 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3206 | min_val = TYPE_MIN_VALUE (type_domain); | |
53fa96c0 | 3207 | offset_int off = wi::to_offset (op01); |
3208 | offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type)); | |
3209 | offset_int remainder; | |
3210 | off = wi::divmod_trunc (off, el_sz, SIGNED, &remainder); | |
3211 | if (remainder == 0 && TREE_CODE (min_val) == INTEGER_CST) | |
3212 | { | |
3213 | off = off + wi::to_offset (min_val); | |
3214 | op01 = wide_int_to_tree (sizetype, off); | |
3215 | return build4_loc (loc, ARRAY_REF, type, op00, op01, | |
3216 | NULL_TREE, NULL_TREE); | |
3217 | } | |
09b42213 | 3218 | } |
3219 | /* Also handle conversion to an empty base class, which | |
3220 | is represented with a NOP_EXPR. */ | |
3221 | else if (is_empty_class (type) | |
3222 | && CLASS_TYPE_P (op00type) | |
3223 | && DERIVED_FROM_P (type, op00type)) | |
3224 | { | |
3225 | *empty_base = true; | |
3226 | return op00; | |
3227 | } | |
3228 | /* ((foo *)&struct_with_foo_field)[1] => COMPONENT_REF */ | |
3229 | else if (RECORD_OR_UNION_TYPE_P (op00type)) | |
3230 | { | |
3231 | tree field = TYPE_FIELDS (op00type); | |
3232 | for (; field; field = DECL_CHAIN (field)) | |
3233 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3234 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3235 | && tree_int_cst_equal (byte_position (field), op01) |
3236 | && (same_type_ignoring_top_level_qualifiers_p | |
3237 | (TREE_TYPE (field), type))) | |
a48667ee | 3238 | return fold_build3 (COMPONENT_REF, type, op00, |
3239 | field, NULL_TREE); | |
09b42213 | 3240 | } |
3241 | } | |
3242 | } | |
3243 | /* *(foo *)fooarrptr => (*fooarrptr)[0] */ | |
3244 | else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE | |
3245 | && (same_type_ignoring_top_level_qualifiers_p | |
3246 | (type, TREE_TYPE (TREE_TYPE (subtype))))) | |
3247 | { | |
3248 | tree type_domain; | |
3249 | tree min_val = size_zero_node; | |
7d8e655d | 3250 | tree newsub |
3251 | = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL); | |
09b42213 | 3252 | if (newsub) |
3253 | sub = newsub; | |
3254 | else | |
3255 | sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub); | |
3256 | type_domain = TYPE_DOMAIN (TREE_TYPE (sub)); | |
3257 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3258 | min_val = TYPE_MIN_VALUE (type_domain); | |
3259 | return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE, | |
3260 | NULL_TREE); | |
3261 | } | |
3262 | ||
3263 | return NULL_TREE; | |
3264 | } | |
3265 | ||
3266 | static tree | |
cf72f34d | 3267 | cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3268 | bool lval, |
09b42213 | 3269 | bool *non_constant_p, bool *overflow_p) |
3270 | { | |
3271 | tree orig_op0 = TREE_OPERAND (t, 0); | |
09b42213 | 3272 | bool empty_base = false; |
09b42213 | 3273 | |
d2c63826 | 3274 | /* We can handle a MEM_REF like an INDIRECT_REF, if MEM_REF's second |
3275 | operand is an integer-zero. Otherwise reject the MEM_REF for now. */ | |
3276 | ||
3277 | if (TREE_CODE (t) == MEM_REF | |
3278 | && (!TREE_OPERAND (t, 1) || !integer_zerop (TREE_OPERAND (t, 1)))) | |
3279 | { | |
3280 | gcc_assert (ctx->quiet); | |
3281 | *non_constant_p = true; | |
3282 | return t; | |
3283 | } | |
3284 | ||
7e0f3388 | 3285 | /* First try to simplify it directly. */ |
3286 | tree r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), orig_op0, | |
3287 | &empty_base); | |
3288 | if (!r) | |
09b42213 | 3289 | { |
7e0f3388 | 3290 | /* If that didn't work, evaluate the operand first. */ |
3291 | tree op0 = cxx_eval_constant_expression (ctx, orig_op0, | |
3292 | /*lval*/false, non_constant_p, | |
3293 | overflow_p); | |
3294 | /* Don't VERIFY_CONSTANT here. */ | |
3295 | if (*non_constant_p) | |
3296 | return t; | |
3297 | ||
cb768824 | 3298 | if (!lval && integer_zerop (op0)) |
3299 | { | |
3300 | if (!ctx->quiet) | |
3301 | error ("dereferencing a null pointer"); | |
3302 | *non_constant_p = true; | |
3303 | return t; | |
3304 | } | |
3305 | ||
7e0f3388 | 3306 | r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), op0, |
3307 | &empty_base); | |
3308 | if (r == NULL_TREE) | |
09b42213 | 3309 | { |
3310 | /* We couldn't fold to a constant value. Make sure it's not | |
3311 | something we should have been able to fold. */ | |
7e0f3388 | 3312 | tree sub = op0; |
3313 | STRIP_NOPS (sub); | |
3314 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3315 | { | |
3316 | gcc_assert (!same_type_ignoring_top_level_qualifiers_p | |
3317 | (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t))); | |
3318 | /* DR 1188 says we don't have to deal with this. */ | |
3319 | if (!ctx->quiet) | |
3320 | error ("accessing value of %qE through a %qT glvalue in a " | |
3321 | "constant expression", build_fold_indirect_ref (sub), | |
3322 | TREE_TYPE (t)); | |
3323 | *non_constant_p = true; | |
3324 | return t; | |
3325 | } | |
3326 | ||
3327 | if (lval && op0 != orig_op0) | |
3328 | return build1 (INDIRECT_REF, TREE_TYPE (t), op0); | |
3329 | if (!lval) | |
3330 | VERIFY_CONSTANT (t); | |
09b42213 | 3331 | return t; |
3332 | } | |
3333 | } | |
3334 | ||
7e0f3388 | 3335 | r = cxx_eval_constant_expression (ctx, r, |
3336 | lval, non_constant_p, overflow_p); | |
3337 | if (*non_constant_p) | |
3338 | return t; | |
3339 | ||
ce4ffd9e | 3340 | /* If we're pulling out the value of an empty base, just return an empty |
09b42213 | 3341 | CONSTRUCTOR. */ |
1227ba74 | 3342 | if (empty_base && !lval) |
09b42213 | 3343 | { |
09b42213 | 3344 | r = build_constructor (TREE_TYPE (t), NULL); |
3345 | TREE_CONSTANT (r) = true; | |
3346 | } | |
3347 | ||
09b42213 | 3348 | return r; |
3349 | } | |
3350 | ||
3351 | /* Complain about R, a VAR_DECL, not being usable in a constant expression. | |
3352 | Shared between potential_constant_expression and | |
3353 | cxx_eval_constant_expression. */ | |
3354 | ||
3355 | static void | |
3356 | non_const_var_error (tree r) | |
3357 | { | |
3358 | tree type = TREE_TYPE (r); | |
3359 | error ("the value of %qD is not usable in a constant " | |
3360 | "expression", r); | |
3361 | /* Avoid error cascade. */ | |
3362 | if (DECL_INITIAL (r) == error_mark_node) | |
3363 | return; | |
3364 | if (DECL_DECLARED_CONSTEXPR_P (r)) | |
3365 | inform (DECL_SOURCE_LOCATION (r), | |
3366 | "%qD used in its own initializer", r); | |
3367 | else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) | |
3368 | { | |
3369 | if (!CP_TYPE_CONST_P (type)) | |
3370 | inform (DECL_SOURCE_LOCATION (r), | |
3371 | "%q#D is not const", r); | |
3372 | else if (CP_TYPE_VOLATILE_P (type)) | |
3373 | inform (DECL_SOURCE_LOCATION (r), | |
3374 | "%q#D is volatile", r); | |
3375 | else if (!DECL_INITIAL (r) | |
c8e3e744 | 3376 | || !TREE_CONSTANT (DECL_INITIAL (r)) |
3377 | || !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (r)) | |
09b42213 | 3378 | inform (DECL_SOURCE_LOCATION (r), |
3379 | "%qD was not initialized with a constant " | |
3380 | "expression", r); | |
3381 | else | |
3382 | gcc_unreachable (); | |
3383 | } | |
ac6641ca | 3384 | else if (TREE_CODE (type) == REFERENCE_TYPE) |
3385 | inform (DECL_SOURCE_LOCATION (r), | |
3386 | "%qD was not initialized with a constant " | |
3387 | "expression", r); | |
09b42213 | 3388 | else |
3389 | { | |
3390 | if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r)) | |
3391 | inform (DECL_SOURCE_LOCATION (r), | |
3392 | "%qD was not declared %<constexpr%>", r); | |
3393 | else | |
3394 | inform (DECL_SOURCE_LOCATION (r), | |
3395 | "%qD does not have integral or enumeration type", | |
3396 | r); | |
3397 | } | |
3398 | } | |
3399 | ||
3400 | /* Subroutine of cxx_eval_constant_expression. | |
3401 | Like cxx_eval_unary_expression, except for trinary expressions. */ | |
3402 | ||
3403 | static tree | |
cf72f34d | 3404 | cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3405 | bool lval, |
09b42213 | 3406 | bool *non_constant_p, bool *overflow_p) |
3407 | { | |
3408 | int i; | |
3409 | tree args[3]; | |
3410 | tree val; | |
3411 | ||
3412 | for (i = 0; i < 3; i++) | |
3413 | { | |
cf72f34d | 3414 | args[i] = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, i), |
1227ba74 | 3415 | lval, |
b2a43197 | 3416 | non_constant_p, overflow_p); |
09b42213 | 3417 | VERIFY_CONSTANT (args[i]); |
3418 | } | |
3419 | ||
3420 | val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t), | |
3421 | args[0], args[1], args[2]); | |
3422 | if (val == NULL_TREE) | |
3423 | return t; | |
3424 | VERIFY_CONSTANT (val); | |
3425 | return val; | |
3426 | } | |
3427 | ||
33603066 | 3428 | /* True if T was declared in a function declared to be constexpr, and |
3429 | therefore potentially constant in C++14. */ | |
3430 | ||
09b42213 | 3431 | bool |
3432 | var_in_constexpr_fn (tree t) | |
3433 | { | |
3434 | tree ctx = DECL_CONTEXT (t); | |
33603066 | 3435 | return (ctx && TREE_CODE (ctx) == FUNCTION_DECL |
09b42213 | 3436 | && DECL_DECLARED_CONSTEXPR_P (ctx)); |
3437 | } | |
3438 | ||
33603066 | 3439 | /* True if T was declared in a function that might be constexpr: either a |
3440 | function that was declared constexpr, or a C++17 lambda op(). */ | |
3441 | ||
3442 | bool | |
3443 | var_in_maybe_constexpr_fn (tree t) | |
3444 | { | |
40e2decb | 3445 | if (cxx_dialect >= cxx17 |
33603066 | 3446 | && DECL_FUNCTION_SCOPE_P (t) |
3447 | && LAMBDA_FUNCTION_P (DECL_CONTEXT (t))) | |
3448 | return true; | |
3449 | return var_in_constexpr_fn (t); | |
3450 | } | |
3451 | ||
93312944 | 3452 | /* We're assigning INIT to TARGET. In do_build_copy_constructor and |
3453 | build_over_call we implement trivial copy of a class with tail padding using | |
3454 | assignment of character arrays, which is valid in normal code, but not in | |
3455 | constexpr evaluation. We don't need to worry about clobbering tail padding | |
3456 | in constexpr evaluation, so strip the type punning. */ | |
3457 | ||
3458 | static void | |
3459 | maybe_simplify_trivial_copy (tree &target, tree &init) | |
3460 | { | |
3461 | if (TREE_CODE (target) == MEM_REF | |
3462 | && TREE_CODE (init) == MEM_REF | |
3463 | && TREE_TYPE (target) == TREE_TYPE (init) | |
3464 | && TREE_CODE (TREE_TYPE (target)) == ARRAY_TYPE | |
3465 | && TREE_TYPE (TREE_TYPE (target)) == unsigned_char_type_node) | |
3466 | { | |
3467 | target = build_fold_indirect_ref (TREE_OPERAND (target, 0)); | |
3468 | init = build_fold_indirect_ref (TREE_OPERAND (init, 0)); | |
3469 | } | |
3470 | } | |
3471 | ||
9c96033c | 3472 | /* Evaluate an INIT_EXPR or MODIFY_EXPR. */ |
3473 | ||
3474 | static tree | |
3475 | cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3476 | bool lval, |
9c96033c | 3477 | bool *non_constant_p, bool *overflow_p) |
3478 | { | |
3479 | constexpr_ctx new_ctx = *ctx; | |
3480 | ||
8a36d0ec | 3481 | tree init = TREE_OPERAND (t, 1); |
3482 | if (TREE_CLOBBER_P (init)) | |
3483 | /* Just ignore clobbers. */ | |
3484 | return void_node; | |
3485 | ||
9c96033c | 3486 | /* First we figure out where we're storing to. */ |
3487 | tree target = TREE_OPERAND (t, 0); | |
93312944 | 3488 | |
3489 | maybe_simplify_trivial_copy (target, init); | |
3490 | ||
9db9fc38 | 3491 | tree type = TREE_TYPE (target); |
9c96033c | 3492 | target = cxx_eval_constant_expression (ctx, target, |
f83e6885 | 3493 | true, |
b2a43197 | 3494 | non_constant_p, overflow_p); |
9c96033c | 3495 | if (*non_constant_p) |
3496 | return t; | |
3497 | ||
cf3cefc9 | 3498 | /* cxx_eval_array_reference for lval = true allows references one past |
3499 | end of array, because it does not know if it is just taking address | |
3500 | (which is valid), or actual dereference. Here we know it is | |
3501 | a dereference, so diagnose it here. */ | |
3502 | for (tree probe = target; probe; ) | |
3503 | { | |
3504 | switch (TREE_CODE (probe)) | |
3505 | { | |
3506 | case ARRAY_REF: | |
3507 | tree nelts, ary; | |
3508 | ary = TREE_OPERAND (probe, 0); | |
51f0c7e2 | 3509 | nelts = get_array_or_vector_nelts (ctx, TREE_TYPE (ary), |
3510 | non_constant_p, overflow_p); | |
cf3cefc9 | 3511 | VERIFY_CONSTANT (nelts); |
3512 | gcc_assert (TREE_CODE (nelts) == INTEGER_CST | |
3513 | && TREE_CODE (TREE_OPERAND (probe, 1)) == INTEGER_CST); | |
cb7bca5f | 3514 | if (wi::to_widest (TREE_OPERAND (probe, 1)) == wi::to_widest (nelts)) |
cf3cefc9 | 3515 | { |
3516 | diag_array_subscript (ctx, ary, TREE_OPERAND (probe, 1)); | |
3517 | *non_constant_p = true; | |
3518 | return t; | |
3519 | } | |
3520 | /* FALLTHRU */ | |
3521 | ||
3522 | case BIT_FIELD_REF: | |
3523 | case COMPONENT_REF: | |
3524 | probe = TREE_OPERAND (probe, 0); | |
3525 | continue; | |
3526 | ||
3527 | default: | |
3528 | probe = NULL_TREE; | |
3529 | continue; | |
3530 | } | |
3531 | } | |
3532 | ||
9db9fc38 | 3533 | if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (target), type)) |
3534 | { | |
3535 | /* For initialization of an empty base, the original target will be | |
3536 | *(base*)this, which the above evaluation resolves to the object | |
3537 | argument, which has the derived type rather than the base type. In | |
3538 | this situation, just evaluate the initializer and return, since | |
3539 | there's no actual data to store. */ | |
3540 | gcc_assert (is_empty_class (type)); | |
3541 | return cxx_eval_constant_expression (ctx, init, false, | |
3542 | non_constant_p, overflow_p); | |
3543 | } | |
3544 | ||
9c96033c | 3545 | /* And then find the underlying variable. */ |
3546 | vec<tree,va_gc> *refs = make_tree_vector(); | |
3547 | tree object = NULL_TREE; | |
3548 | for (tree probe = target; object == NULL_TREE; ) | |
3549 | { | |
3550 | switch (TREE_CODE (probe)) | |
3551 | { | |
3552 | case BIT_FIELD_REF: | |
3553 | case COMPONENT_REF: | |
3554 | case ARRAY_REF: | |
3555 | vec_safe_push (refs, TREE_OPERAND (probe, 1)); | |
3556 | vec_safe_push (refs, TREE_TYPE (probe)); | |
3557 | probe = TREE_OPERAND (probe, 0); | |
3558 | break; | |
3559 | ||
3560 | default: | |
3561 | object = probe; | |
9c96033c | 3562 | } |
3563 | } | |
3564 | ||
3565 | /* And then find/build up our initializer for the path to the subobject | |
3566 | we're initializing. */ | |
6fe83e54 | 3567 | tree *valp; |
43b7271d | 3568 | if (object == ctx->object && VAR_P (object) |
3569 | && DECL_NAME (object) && ctx->call == NULL) | |
3570 | /* The variable we're building up an aggregate initializer for is outside | |
3571 | the constant-expression, so don't evaluate the store. We check | |
3572 | DECL_NAME to handle TARGET_EXPR temporaries, which are fair game. */ | |
3573 | valp = NULL; | |
3574 | else if (DECL_P (object)) | |
6fe83e54 | 3575 | valp = ctx->values->get (object); |
3576 | else | |
3577 | valp = NULL; | |
9c96033c | 3578 | if (!valp) |
3579 | { | |
3580 | /* A constant-expression cannot modify objects from outside the | |
3581 | constant-expression. */ | |
f83e6885 | 3582 | if (!ctx->quiet) |
ea034e2c | 3583 | error ("modification of %qE is not a constant expression", object); |
9c96033c | 3584 | *non_constant_p = true; |
3585 | return t; | |
3586 | } | |
9db9fc38 | 3587 | type = TREE_TYPE (object); |
a02b42fe | 3588 | bool no_zero_init = true; |
58b0f9ce | 3589 | |
3590 | vec<tree,va_gc> *ctors = make_tree_vector (); | |
9c96033c | 3591 | while (!refs->is_empty()) |
3592 | { | |
3593 | if (*valp == NULL_TREE) | |
3594 | { | |
3595 | *valp = build_constructor (type, NULL); | |
a02b42fe | 3596 | CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp) = no_zero_init; |
9c96033c | 3597 | } |
92fe8840 | 3598 | else if (TREE_CODE (*valp) == STRING_CST) |
3599 | { | |
3600 | /* An array was initialized with a string constant, and now | |
3601 | we're writing into one of its elements. Explode the | |
3602 | single initialization into a set of element | |
3603 | initializations. */ | |
3604 | gcc_assert (TREE_CODE (type) == ARRAY_TYPE); | |
3605 | ||
3606 | tree string = *valp; | |
3607 | tree elt_type = TREE_TYPE (type); | |
3608 | unsigned chars_per_elt = (TYPE_PRECISION (elt_type) | |
3609 | / TYPE_PRECISION (char_type_node)); | |
3610 | unsigned num_elts = TREE_STRING_LENGTH (string) / chars_per_elt; | |
3611 | tree ary_ctor = build_constructor (type, NULL); | |
3612 | ||
3613 | vec_safe_reserve (CONSTRUCTOR_ELTS (ary_ctor), num_elts); | |
3614 | for (unsigned ix = 0; ix != num_elts; ix++) | |
3615 | { | |
3616 | constructor_elt elt = | |
3617 | { | |
3618 | build_int_cst (size_type_node, ix), | |
3619 | extract_string_elt (string, chars_per_elt, ix) | |
3620 | }; | |
3621 | CONSTRUCTOR_ELTS (ary_ctor)->quick_push (elt); | |
3622 | } | |
3623 | ||
3624 | *valp = ary_ctor; | |
3625 | } | |
3626 | ||
a02b42fe | 3627 | /* If the value of object is already zero-initialized, any new ctors for |
3628 | subobjects will also be zero-initialized. */ | |
3629 | no_zero_init = CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp); | |
9c96033c | 3630 | |
58b0f9ce | 3631 | vec_safe_push (ctors, *valp); |
3632 | ||
7963b19d | 3633 | enum tree_code code = TREE_CODE (type); |
9c96033c | 3634 | type = refs->pop(); |
7963b19d | 3635 | tree index = refs->pop(); |
9c96033c | 3636 | |
9c96033c | 3637 | constructor_elt *cep = NULL; |
7963b19d | 3638 | if (code == ARRAY_TYPE) |
3639 | { | |
3640 | HOST_WIDE_INT i | |
3641 | = find_array_ctor_elt (*valp, index, /*insert*/true); | |
3642 | gcc_assert (i >= 0); | |
3643 | cep = CONSTRUCTOR_ELT (*valp, i); | |
3644 | gcc_assert (TREE_CODE (cep->index) != RANGE_EXPR); | |
3645 | } | |
3646 | else | |
3647 | { | |
3648 | gcc_assert (TREE_CODE (index) == FIELD_DECL); | |
13ee2de7 | 3649 | |
3650 | /* We must keep the CONSTRUCTOR's ELTS in FIELD order. | |
3651 | Usually we meet initializers in that order, but it is | |
3652 | possible for base types to be placed not in program | |
3653 | order. */ | |
3654 | tree fields = TYPE_FIELDS (DECL_CONTEXT (index)); | |
3655 | unsigned HOST_WIDE_INT idx; | |
3656 | ||
ef782365 | 3657 | if (code == UNION_TYPE && CONSTRUCTOR_NELTS (*valp) |
3658 | && CONSTRUCTOR_ELT (*valp, 0)->index != index) | |
3659 | /* Changing active member. */ | |
3660 | vec_safe_truncate (CONSTRUCTOR_ELTS (*valp), 0); | |
3661 | ||
13ee2de7 | 3662 | for (idx = 0; |
7963b19d | 3663 | vec_safe_iterate (CONSTRUCTOR_ELTS (*valp), idx, &cep); |
13ee2de7 | 3664 | idx++, fields = DECL_CHAIN (fields)) |
7963b19d | 3665 | { |
13ee2de7 | 3666 | if (index == cep->index) |
3667 | goto found; | |
3668 | ||
3669 | /* The field we're initializing must be on the field | |
3670 | list. Look to see if it is present before the | |
3671 | field the current ELT initializes. */ | |
3672 | for (; fields != cep->index; fields = DECL_CHAIN (fields)) | |
3673 | if (index == fields) | |
3674 | goto insert; | |
7963b19d | 3675 | } |
13ee2de7 | 3676 | |
3677 | /* We fell off the end of the CONSTRUCTOR, so insert a new | |
3678 | entry at the end. */ | |
3679 | insert: | |
3680 | { | |
3681 | constructor_elt ce = { index, NULL_TREE }; | |
3682 | ||
3683 | vec_safe_insert (CONSTRUCTOR_ELTS (*valp), idx, ce); | |
3684 | cep = CONSTRUCTOR_ELT (*valp, idx); | |
3685 | } | |
3686 | found:; | |
7963b19d | 3687 | } |
9c96033c | 3688 | valp = &cep->value; |
3689 | } | |
3690 | release_tree_vector (refs); | |
3691 | ||
469dc5a6 | 3692 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) |
9c96033c | 3693 | { |
3694 | /* Create a new CONSTRUCTOR in case evaluation of the initializer | |
3695 | wants to modify it. */ | |
469dc5a6 | 3696 | if (*valp == NULL_TREE) |
6cded085 | 3697 | { |
6993e708 | 3698 | *valp = build_constructor (type, NULL); |
3699 | CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp) = no_zero_init; | |
6cded085 | 3700 | } |
6993e708 | 3701 | else if (TREE_CODE (*valp) == PTRMEM_CST) |
3702 | *valp = cplus_expand_constant (*valp); | |
3703 | new_ctx.ctor = *valp; | |
9c96033c | 3704 | new_ctx.object = target; |
3705 | } | |
3706 | ||
8a36d0ec | 3707 | init = cxx_eval_constant_expression (&new_ctx, init, false, |
3708 | non_constant_p, overflow_p); | |
7b9f713d | 3709 | /* Don't share a CONSTRUCTOR that might be changed later. */ |
e283bb4f | 3710 | init = unshare_constructor (init); |
9c96033c | 3711 | if (target == object) |
5579a199 | 3712 | /* The hash table might have moved since the get earlier. */ |
3713 | valp = ctx->values->get (object); | |
3714 | ||
3715 | if (TREE_CODE (init) == CONSTRUCTOR) | |
469dc5a6 | 3716 | { |
5579a199 | 3717 | /* An outer ctx->ctor might be pointing to *valp, so replace |
3718 | its contents. */ | |
3719 | CONSTRUCTOR_ELTS (*valp) = CONSTRUCTOR_ELTS (init); | |
3720 | TREE_CONSTANT (*valp) = TREE_CONSTANT (init); | |
3721 | TREE_SIDE_EFFECTS (*valp) = TREE_SIDE_EFFECTS (init); | |
b9786e35 | 3722 | CONSTRUCTOR_NO_IMPLICIT_ZERO (*valp) |
3723 | = CONSTRUCTOR_NO_IMPLICIT_ZERO (init); | |
469dc5a6 | 3724 | } |
9c96033c | 3725 | else |
5579a199 | 3726 | *valp = init; |
58b0f9ce | 3727 | |
5579a199 | 3728 | /* Update TREE_CONSTANT and TREE_SIDE_EFFECTS on enclosing |
3729 | CONSTRUCTORs, if any. */ | |
3730 | tree elt; | |
3731 | unsigned i; | |
3732 | bool c = TREE_CONSTANT (init); | |
3733 | bool s = TREE_SIDE_EFFECTS (init); | |
3734 | if (!c || s) | |
3735 | FOR_EACH_VEC_SAFE_ELT (ctors, i, elt) | |
3736 | { | |
3737 | if (!c) | |
3738 | TREE_CONSTANT (elt) = false; | |
3739 | if (s) | |
3740 | TREE_SIDE_EFFECTS (elt) = true; | |
3741 | } | |
58b0f9ce | 3742 | release_tree_vector (ctors); |
9c96033c | 3743 | |
3744 | if (*non_constant_p) | |
3745 | return t; | |
1227ba74 | 3746 | else if (lval) |
9c96033c | 3747 | return target; |
3748 | else | |
dfac7dd2 | 3749 | return init; |
9c96033c | 3750 | } |
3751 | ||
3752 | /* Evaluate a ++ or -- expression. */ | |
3753 | ||
3754 | static tree | |
3755 | cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3756 | bool lval, |
9c96033c | 3757 | bool *non_constant_p, bool *overflow_p) |
3758 | { | |
3759 | enum tree_code code = TREE_CODE (t); | |
3760 | tree type = TREE_TYPE (t); | |
3761 | tree op = TREE_OPERAND (t, 0); | |
3762 | tree offset = TREE_OPERAND (t, 1); | |
3763 | gcc_assert (TREE_CONSTANT (offset)); | |
3764 | ||
3765 | /* The operand as an lvalue. */ | |
f83e6885 | 3766 | op = cxx_eval_constant_expression (ctx, op, true, |
b2a43197 | 3767 | non_constant_p, overflow_p); |
9c96033c | 3768 | |
3769 | /* The operand as an rvalue. */ | |
c017458d | 3770 | tree val |
3771 | = cxx_eval_constant_expression (ctx, op, false, | |
3772 | non_constant_p, overflow_p); | |
35f2c28f | 3773 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
3774 | a local array in a constexpr function. */ | |
3775 | bool ptr = POINTER_TYPE_P (TREE_TYPE (val)); | |
3776 | if (!ptr) | |
3777 | VERIFY_CONSTANT (val); | |
9c96033c | 3778 | |
3779 | /* The modified value. */ | |
3780 | bool inc = (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR); | |
c8a8f7ad | 3781 | tree mod; |
3782 | if (POINTER_TYPE_P (type)) | |
3783 | { | |
3784 | /* The middle end requires pointers to use POINTER_PLUS_EXPR. */ | |
3785 | offset = convert_to_ptrofftype (offset); | |
3786 | if (!inc) | |
3787 | offset = fold_build1 (NEGATE_EXPR, TREE_TYPE (offset), offset); | |
3788 | mod = fold_build2 (POINTER_PLUS_EXPR, type, val, offset); | |
3789 | } | |
3790 | else | |
3791 | mod = fold_build2 (inc ? PLUS_EXPR : MINUS_EXPR, type, val, offset); | |
35f2c28f | 3792 | if (!ptr) |
3793 | VERIFY_CONSTANT (mod); | |
9c96033c | 3794 | |
3795 | /* Storing the modified value. */ | |
3796 | tree store = build2 (MODIFY_EXPR, type, op, mod); | |
f83e6885 | 3797 | cxx_eval_constant_expression (ctx, store, |
b2a43197 | 3798 | true, non_constant_p, overflow_p); |
9c96033c | 3799 | |
3800 | /* And the value of the expression. */ | |
3801 | if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) | |
3802 | { | |
3803 | /* Prefix ops are lvalues. */ | |
1227ba74 | 3804 | if (lval) |
9c96033c | 3805 | return op; |
3806 | else | |
3807 | /* But we optimize when the caller wants an rvalue. */ | |
3808 | return mod; | |
3809 | } | |
3810 | else | |
3811 | /* Postfix ops are rvalues. */ | |
3812 | return val; | |
3813 | } | |
3814 | ||
00f21715 | 3815 | /* Predicates for the meaning of *jump_target. */ |
3816 | ||
3817 | static bool | |
3818 | returns (tree *jump_target) | |
3819 | { | |
3820 | return *jump_target | |
d29e4e8c | 3821 | && (TREE_CODE (*jump_target) == RETURN_EXPR |
3822 | || (TREE_CODE (*jump_target) == LABEL_DECL | |
3823 | && LABEL_DECL_CDTOR (*jump_target))); | |
00f21715 | 3824 | } |
3825 | ||
3826 | static bool | |
3827 | breaks (tree *jump_target) | |
3828 | { | |
3829 | return *jump_target | |
cf03ba19 | 3830 | && ((TREE_CODE (*jump_target) == LABEL_DECL |
3831 | && LABEL_DECL_BREAK (*jump_target)) | |
3832 | || TREE_CODE (*jump_target) == EXIT_EXPR); | |
00f21715 | 3833 | } |
3834 | ||
3835 | static bool | |
3836 | continues (tree *jump_target) | |
3837 | { | |
3838 | return *jump_target | |
3839 | && TREE_CODE (*jump_target) == LABEL_DECL | |
3840 | && LABEL_DECL_CONTINUE (*jump_target); | |
3841 | } | |
3842 | ||
3843 | static bool | |
3844 | switches (tree *jump_target) | |
3845 | { | |
3846 | return *jump_target | |
3847 | && TREE_CODE (*jump_target) == INTEGER_CST; | |
3848 | } | |
3849 | ||
3850 | /* Subroutine of cxx_eval_statement_list. Determine whether the statement | |
2a2770c6 | 3851 | STMT matches *jump_target. If we're looking for a case label and we see |
3852 | the default label, note it in ctx->css_state. */ | |
00f21715 | 3853 | |
3854 | static bool | |
2a2770c6 | 3855 | label_matches (const constexpr_ctx *ctx, tree *jump_target, tree stmt) |
00f21715 | 3856 | { |
00f21715 | 3857 | switch (TREE_CODE (*jump_target)) |
3858 | { | |
3859 | case LABEL_DECL: | |
3860 | if (TREE_CODE (stmt) == LABEL_EXPR | |
3861 | && LABEL_EXPR_LABEL (stmt) == *jump_target) | |
3862 | return true; | |
3863 | break; | |
3864 | ||
3865 | case INTEGER_CST: | |
3866 | if (TREE_CODE (stmt) == CASE_LABEL_EXPR) | |
3867 | { | |
2a2770c6 | 3868 | gcc_assert (ctx->css_state != NULL); |
00f21715 | 3869 | if (!CASE_LOW (stmt)) |
2a2770c6 | 3870 | { |
3871 | /* default: should appear just once in a SWITCH_EXPR | |
3872 | body (excluding nested SWITCH_EXPR). */ | |
3873 | gcc_assert (*ctx->css_state != css_default_seen); | |
3874 | /* When evaluating SWITCH_EXPR body for the second time, | |
3875 | return true for the default: label. */ | |
3876 | if (*ctx->css_state == css_default_processing) | |
3877 | return true; | |
3878 | *ctx->css_state = css_default_seen; | |
3879 | } | |
83c375ba | 3880 | else if (CASE_HIGH (stmt)) |
3881 | { | |
3882 | if (tree_int_cst_le (CASE_LOW (stmt), *jump_target) | |
3883 | && tree_int_cst_le (*jump_target, CASE_HIGH (stmt))) | |
3884 | return true; | |
3885 | } | |
00f21715 | 3886 | else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt))) |
3887 | return true; | |
3888 | } | |
3889 | break; | |
3890 | ||
3891 | default: | |
3892 | gcc_unreachable (); | |
3893 | } | |
3894 | return false; | |
3895 | } | |
3896 | ||
3897 | /* Evaluate a STATEMENT_LIST for side-effects. Handles various jump | |
3898 | semantics, for switch, break, continue, and return. */ | |
3899 | ||
3900 | static tree | |
3901 | cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3902 | bool *non_constant_p, bool *overflow_p, |
3903 | tree *jump_target) | |
3904 | { | |
3905 | tree_stmt_iterator i; | |
da7981e0 | 3906 | tree local_target; |
efea7c64 | 3907 | /* In a statement-expression we want to return the last value. |
3908 | For empty statement expression return void_node. */ | |
3909 | tree r = void_node; | |
da7981e0 | 3910 | if (!jump_target) |
3911 | { | |
3912 | local_target = NULL_TREE; | |
3913 | jump_target = &local_target; | |
3914 | } | |
00f21715 | 3915 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) |
3916 | { | |
00f21715 | 3917 | tree stmt = tsi_stmt (i); |
442c4003 | 3918 | if (TREE_CODE (stmt) == DEBUG_BEGIN_STMT) |
3919 | continue; | |
da7981e0 | 3920 | r = cxx_eval_constant_expression (ctx, stmt, false, |
3921 | non_constant_p, overflow_p, | |
3922 | jump_target); | |
00f21715 | 3923 | if (*non_constant_p) |
3924 | break; | |
3925 | if (returns (jump_target) || breaks (jump_target)) | |
3926 | break; | |
3927 | } | |
da7981e0 | 3928 | return r; |
00f21715 | 3929 | } |
3930 | ||
3931 | /* Evaluate a LOOP_EXPR for side-effects. Handles break and return | |
3932 | semantics; continue semantics are covered by cxx_eval_statement_list. */ | |
3933 | ||
3934 | static tree | |
3935 | cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3936 | bool *non_constant_p, bool *overflow_p, |
3937 | tree *jump_target) | |
3938 | { | |
2631cb67 | 3939 | constexpr_ctx new_ctx = *ctx; |
3940 | ||
00f21715 | 3941 | tree body = TREE_OPERAND (t, 0); |
21483ab7 | 3942 | int count = 0; |
5370eb8d | 3943 | do |
00f21715 | 3944 | { |
2631cb67 | 3945 | hash_set<tree> save_exprs; |
3946 | new_ctx.save_exprs = &save_exprs; | |
3947 | ||
cf03ba19 | 3948 | cxx_eval_constant_expression (&new_ctx, body, /*lval*/false, |
3949 | non_constant_p, overflow_p, jump_target); | |
2631cb67 | 3950 | |
3951 | /* Forget saved values of SAVE_EXPRs. */ | |
3952 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
3953 | iter != save_exprs.end(); ++iter) | |
3954 | new_ctx.values->remove (*iter); | |
21483ab7 | 3955 | if (++count >= constexpr_loop_limit) |
3956 | { | |
3957 | if (!ctx->quiet) | |
3958 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
5967b28b | 3959 | "%<constexpr%> loop iteration count exceeds limit of %d " |
21483ab7 | 3960 | "(use -fconstexpr-loop-limit= to increase the limit)", |
3961 | constexpr_loop_limit); | |
3962 | *non_constant_p = true; | |
3963 | break; | |
3964 | } | |
00f21715 | 3965 | } |
2a2770c6 | 3966 | while (!returns (jump_target) |
3967 | && !breaks (jump_target) | |
3968 | && !switches (jump_target) | |
3969 | && !*non_constant_p); | |
5370eb8d | 3970 | |
00f21715 | 3971 | if (breaks (jump_target)) |
3972 | *jump_target = NULL_TREE; | |
2631cb67 | 3973 | |
00f21715 | 3974 | return NULL_TREE; |
3975 | } | |
3976 | ||
3977 | /* Evaluate a SWITCH_EXPR for side-effects. Handles switch and break jump | |
3978 | semantics. */ | |
3979 | ||
3980 | static tree | |
3981 | cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 3982 | bool *non_constant_p, bool *overflow_p, |
3983 | tree *jump_target) | |
3984 | { | |
3985 | tree cond = TREE_OPERAND (t, 0); | |
f83e6885 | 3986 | cond = cxx_eval_constant_expression (ctx, cond, false, |
b2a43197 | 3987 | non_constant_p, overflow_p); |
00f21715 | 3988 | VERIFY_CONSTANT (cond); |
3989 | *jump_target = cond; | |
3990 | ||
3991 | tree body = TREE_OPERAND (t, 1); | |
2a2770c6 | 3992 | constexpr_ctx new_ctx = *ctx; |
3993 | constexpr_switch_state css = css_default_not_seen; | |
3994 | new_ctx.css_state = &css; | |
3995 | cxx_eval_constant_expression (&new_ctx, body, false, | |
3996 | non_constant_p, overflow_p, jump_target); | |
3997 | if (switches (jump_target) && css == css_default_seen) | |
3998 | { | |
3999 | /* If the SWITCH_EXPR body has default: label, process it once again, | |
4000 | this time instructing label_matches to return true for default: | |
4001 | label on switches (jump_target). */ | |
4002 | css = css_default_processing; | |
4003 | cxx_eval_constant_expression (&new_ctx, body, false, | |
4004 | non_constant_p, overflow_p, jump_target); | |
4005 | } | |
00f21715 | 4006 | if (breaks (jump_target) || switches (jump_target)) |
4007 | *jump_target = NULL_TREE; | |
4008 | return NULL_TREE; | |
4009 | } | |
4010 | ||
85de9604 | 4011 | /* Find the object of TYPE under initialization in CTX. */ |
4012 | ||
4013 | static tree | |
4014 | lookup_placeholder (const constexpr_ctx *ctx, bool lval, tree type) | |
4015 | { | |
def8e41f | 4016 | if (!ctx) |
85de9604 | 4017 | return NULL_TREE; |
4018 | ||
4019 | /* We could use ctx->object unconditionally, but using ctx->ctor when we | |
4020 | can is a minor optimization. */ | |
def8e41f | 4021 | if (!lval && ctx->ctor && same_type_p (TREE_TYPE (ctx->ctor), type)) |
85de9604 | 4022 | return ctx->ctor; |
4023 | ||
def8e41f | 4024 | if (!ctx->object) |
4025 | return NULL_TREE; | |
4026 | ||
85de9604 | 4027 | /* Since an object cannot have a field of its own type, we can search outward |
4028 | from ctx->object to find the unique containing object of TYPE. */ | |
4029 | tree ob = ctx->object; | |
4030 | while (ob) | |
4031 | { | |
4032 | if (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (ob), type)) | |
4033 | break; | |
4034 | if (handled_component_p (ob)) | |
4035 | ob = TREE_OPERAND (ob, 0); | |
4036 | else | |
4037 | ob = NULL_TREE; | |
4038 | } | |
4039 | ||
4040 | return ob; | |
4041 | } | |
4042 | ||
09b42213 | 4043 | /* Attempt to reduce the expression T to a constant value. |
4044 | On failure, issue diagnostic and return error_mark_node. */ | |
4045 | /* FIXME unify with c_fully_fold */ | |
9c96033c | 4046 | /* FIXME overflow_p is too global */ |
09b42213 | 4047 | |
4048 | static tree | |
cf72f34d | 4049 | cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 4050 | bool lval, |
00f21715 | 4051 | bool *non_constant_p, bool *overflow_p, |
4052 | tree *jump_target) | |
09b42213 | 4053 | { |
cf72f34d | 4054 | constexpr_ctx new_ctx; |
09b42213 | 4055 | tree r = t; |
4056 | ||
2a2770c6 | 4057 | if (jump_target && *jump_target) |
4058 | { | |
4059 | /* If we are jumping, ignore all statements/expressions except those | |
4060 | that could have LABEL_EXPR or CASE_LABEL_EXPR in their bodies. */ | |
4061 | switch (TREE_CODE (t)) | |
4062 | { | |
4063 | case BIND_EXPR: | |
4064 | case STATEMENT_LIST: | |
4065 | case LOOP_EXPR: | |
4066 | case COND_EXPR: | |
4067 | break; | |
4068 | case LABEL_EXPR: | |
4069 | case CASE_LABEL_EXPR: | |
4070 | if (label_matches (ctx, jump_target, t)) | |
4071 | /* Found it. */ | |
4072 | *jump_target = NULL_TREE; | |
4073 | return NULL_TREE; | |
4074 | default: | |
4075 | return NULL_TREE; | |
4076 | } | |
4077 | } | |
09b42213 | 4078 | if (t == error_mark_node) |
4079 | { | |
4080 | *non_constant_p = true; | |
4081 | return t; | |
4082 | } | |
4083 | if (CONSTANT_CLASS_P (t)) | |
4084 | { | |
c4fa85c9 | 4085 | if (TREE_OVERFLOW (t)) |
4086 | { | |
4087 | if (!ctx->quiet) | |
4088 | permerror (input_location, "overflow in constant expression"); | |
4089 | if (!flag_permissive || ctx->quiet) | |
4090 | *overflow_p = true; | |
4091 | } | |
cb768824 | 4092 | |
4093 | if (TREE_CODE (t) == INTEGER_CST | |
4094 | && TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE | |
4095 | && !integer_zerop (t)) | |
4096 | { | |
4097 | if (!ctx->quiet) | |
4098 | error ("value %qE of type %qT is not a constant expression", | |
4099 | t, TREE_TYPE (t)); | |
4100 | *non_constant_p = true; | |
4101 | } | |
4102 | ||
09b42213 | 4103 | return t; |
4104 | } | |
09b42213 | 4105 | |
cb768824 | 4106 | tree_code tcode = TREE_CODE (t); |
4107 | switch (tcode) | |
09b42213 | 4108 | { |
9c96033c | 4109 | case RESULT_DECL: |
1227ba74 | 4110 | if (lval) |
9c96033c | 4111 | return t; |
4112 | /* We ask for an rvalue for the RESULT_DECL when indirecting | |
92a9c89e | 4113 | through an invisible reference, or in named return value |
4114 | optimization. */ | |
8ea8d065 | 4115 | if (tree *p = ctx->values->get (t)) |
4116 | return *p; | |
4117 | else | |
4118 | { | |
4119 | if (!ctx->quiet) | |
4120 | error ("%qE is not a constant expression", t); | |
4121 | *non_constant_p = true; | |
4122 | } | |
4123 | break; | |
9c96033c | 4124 | |
09b42213 | 4125 | case VAR_DECL: |
9c8aeb66 | 4126 | if (DECL_HAS_VALUE_EXPR_P (t)) |
33603066 | 4127 | return cxx_eval_constant_expression (ctx, DECL_VALUE_EXPR (t), |
4128 | lval, non_constant_p, overflow_p); | |
e3533433 | 4129 | /* fall through */ |
8b2b2f24 | 4130 | case CONST_DECL: |
4131 | /* We used to not check lval for CONST_DECL, but darwin.c uses | |
4132 | CONST_DECL for aggregate constants. */ | |
1227ba74 | 4133 | if (lval) |
09b42213 | 4134 | return t; |
594cc00c | 4135 | if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
4136 | && is_really_empty_class (TREE_TYPE (t))) | |
c7282bf2 | 4137 | { |
4138 | /* If the class is empty, we aren't actually loading anything. */ | |
4139 | r = build_constructor (TREE_TYPE (t), NULL); | |
4140 | TREE_CONSTANT (r) = true; | |
4141 | } | |
4142 | else if (ctx->strict) | |
2055d27a | 4143 | r = decl_really_constant_value (t); |
4144 | else | |
4145 | r = decl_constant_value (t); | |
09b42213 | 4146 | if (TREE_CODE (r) == TARGET_EXPR |
4147 | && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR) | |
4148 | r = TARGET_EXPR_INITIAL (r); | |
f4ae4202 | 4149 | if (VAR_P (r)) |
cf72f34d | 4150 | if (tree *p = ctx->values->get (r)) |
a143e277 | 4151 | if (*p != NULL_TREE) |
4152 | r = *p; | |
09b42213 | 4153 | if (DECL_P (r)) |
4154 | { | |
f83e6885 | 4155 | if (!ctx->quiet) |
09b42213 | 4156 | non_const_var_error (r); |
4157 | *non_constant_p = true; | |
4158 | } | |
4159 | break; | |
4160 | ||
90567983 | 4161 | case DEBUG_BEGIN_STMT: |
4162 | /* ??? It might be nice to retain this information somehow, so | |
4163 | as to be able to step into a constexpr function call. */ | |
4164 | /* Fall through. */ | |
4165 | ||
09b42213 | 4166 | case FUNCTION_DECL: |
4167 | case TEMPLATE_DECL: | |
4168 | case LABEL_DECL: | |
00f21715 | 4169 | case LABEL_EXPR: |
4170 | case CASE_LABEL_EXPR: | |
2a2770c6 | 4171 | case PREDICT_EXPR: |
09b42213 | 4172 | return t; |
4173 | ||
4174 | case PARM_DECL: | |
88a59139 | 4175 | if (lval && TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE) |
9c96033c | 4176 | /* glvalue use. */; |
4177 | else if (tree *p = ctx->values->get (r)) | |
4178 | r = *p; | |
1227ba74 | 4179 | else if (lval) |
09b42213 | 4180 | /* Defer in case this is only used for its type. */; |
1eb418cc | 4181 | else if (TREE_CODE (TREE_TYPE (t)) == REFERENCE_TYPE) |
4182 | /* Defer, there's no lvalue->rvalue conversion. */; | |
53d2f3de | 4183 | else if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
4184 | && is_really_empty_class (TREE_TYPE (t))) | |
a6613de7 | 4185 | { |
4186 | /* If the class is empty, we aren't actually loading anything. */ | |
4187 | r = build_constructor (TREE_TYPE (t), NULL); | |
4188 | TREE_CONSTANT (r) = true; | |
4189 | } | |
09b42213 | 4190 | else |
4191 | { | |
f83e6885 | 4192 | if (!ctx->quiet) |
09b42213 | 4193 | error ("%qE is not a constant expression", t); |
4194 | *non_constant_p = true; | |
4195 | } | |
4196 | break; | |
4197 | ||
4198 | case CALL_EXPR: | |
4199 | case AGGR_INIT_EXPR: | |
1227ba74 | 4200 | r = cxx_eval_call_expression (ctx, t, lval, |
09b42213 | 4201 | non_constant_p, overflow_p); |
4202 | break; | |
4203 | ||
9c96033c | 4204 | case DECL_EXPR: |
4205 | { | |
4206 | r = DECL_EXPR_DECL (t); | |
4207 | if (AGGREGATE_TYPE_P (TREE_TYPE (r)) | |
4208 | || VECTOR_TYPE_P (TREE_TYPE (r))) | |
4209 | { | |
4210 | new_ctx = *ctx; | |
4211 | new_ctx.object = r; | |
4212 | new_ctx.ctor = build_constructor (TREE_TYPE (r), NULL); | |
4213 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
4214 | new_ctx.values->put (r, new_ctx.ctor); | |
4215 | ctx = &new_ctx; | |
4216 | } | |
4217 | ||
4218 | if (tree init = DECL_INITIAL (r)) | |
4219 | { | |
4220 | init = cxx_eval_constant_expression (ctx, init, | |
f83e6885 | 4221 | false, |
b2a43197 | 4222 | non_constant_p, overflow_p); |
5898f0d7 | 4223 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 4224 | init = unshare_constructor (init); |
9c96033c | 4225 | ctx->values->put (r, init); |
4226 | } | |
4227 | else if (ctx == &new_ctx) | |
4228 | /* We gave it a CONSTRUCTOR above. */; | |
4229 | else | |
4230 | ctx->values->put (r, NULL_TREE); | |
4231 | } | |
4232 | break; | |
4233 | ||
09b42213 | 4234 | case TARGET_EXPR: |
4235 | if (!literal_type_p (TREE_TYPE (t))) | |
4236 | { | |
f83e6885 | 4237 | if (!ctx->quiet) |
09b42213 | 4238 | { |
4239 | error ("temporary of non-literal type %qT in a " | |
4240 | "constant expression", TREE_TYPE (t)); | |
4241 | explain_non_literal_class (TREE_TYPE (t)); | |
4242 | } | |
4243 | *non_constant_p = true; | |
4244 | break; | |
4245 | } | |
cf72f34d | 4246 | if ((AGGREGATE_TYPE_P (TREE_TYPE (t)) || VECTOR_TYPE_P (TREE_TYPE (t)))) |
4247 | { | |
4248 | /* We're being expanded without an explicit target, so start | |
4249 | initializing a new object; expansion with an explicit target | |
4250 | strips the TARGET_EXPR before we get here. */ | |
4251 | new_ctx = *ctx; | |
4252 | new_ctx.ctor = build_constructor (TREE_TYPE (t), NULL); | |
4253 | CONSTRUCTOR_NO_IMPLICIT_ZERO (new_ctx.ctor) = true; | |
4254 | new_ctx.object = TARGET_EXPR_SLOT (t); | |
4255 | ctx->values->put (new_ctx.object, new_ctx.ctor); | |
4256 | ctx = &new_ctx; | |
4257 | } | |
1227ba74 | 4258 | /* Pass false for 'lval' because this indicates |
09b42213 | 4259 | initialization of a temporary. */ |
cf72f34d | 4260 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 4261 | false, |
b2a43197 | 4262 | non_constant_p, overflow_p); |
09b42213 | 4263 | if (!*non_constant_p) |
4264 | /* Adjust the type of the result to the type of the temporary. */ | |
4265 | r = adjust_temp_type (TREE_TYPE (t), r); | |
1227ba74 | 4266 | if (lval) |
1eb418cc | 4267 | { |
4268 | tree slot = TARGET_EXPR_SLOT (t); | |
e283bb4f | 4269 | r = unshare_constructor (r); |
1eb418cc | 4270 | ctx->values->put (slot, r); |
4271 | return slot; | |
4272 | } | |
09b42213 | 4273 | break; |
4274 | ||
9c96033c | 4275 | case INIT_EXPR: |
9c96033c | 4276 | case MODIFY_EXPR: |
2a2770c6 | 4277 | gcc_assert (jump_target == NULL || *jump_target == NULL_TREE); |
1227ba74 | 4278 | r = cxx_eval_store_expression (ctx, t, lval, |
9c96033c | 4279 | non_constant_p, overflow_p); |
4280 | break; | |
4281 | ||
09b42213 | 4282 | case SCOPE_REF: |
cf72f34d | 4283 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 4284 | lval, |
b2a43197 | 4285 | non_constant_p, overflow_p); |
09b42213 | 4286 | break; |
4287 | ||
4288 | case RETURN_EXPR: | |
10fb495c | 4289 | if (TREE_OPERAND (t, 0) != NULL_TREE) |
4290 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
4291 | lval, | |
4292 | non_constant_p, overflow_p); | |
2c572f5f | 4293 | if (jump_target) |
4294 | *jump_target = t; | |
4295 | else | |
4296 | { | |
4297 | /* Can happen with ({ return true; }) && false; passed to | |
4298 | maybe_constant_value. There is nothing to jump over in this | |
4299 | case, and the bug will be diagnosed later. */ | |
4300 | gcc_assert (ctx->quiet); | |
4301 | *non_constant_p = true; | |
4302 | } | |
00f21715 | 4303 | break; |
4304 | ||
e0e672a0 | 4305 | case SAVE_EXPR: |
4306 | /* Avoid evaluating a SAVE_EXPR more than once. */ | |
4307 | if (tree *p = ctx->values->get (t)) | |
4308 | r = *p; | |
4309 | else | |
4310 | { | |
c8f6aeb1 | 4311 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), false, |
e0e672a0 | 4312 | non_constant_p, overflow_p); |
4313 | ctx->values->put (t, r); | |
2631cb67 | 4314 | if (ctx->save_exprs) |
4315 | ctx->save_exprs->add (t); | |
e0e672a0 | 4316 | } |
4317 | break; | |
4318 | ||
09b42213 | 4319 | case NON_LVALUE_EXPR: |
4320 | case TRY_CATCH_EXPR: | |
7f67d68c | 4321 | case TRY_BLOCK: |
09b42213 | 4322 | case CLEANUP_POINT_EXPR: |
4323 | case MUST_NOT_THROW_EXPR: | |
9c96033c | 4324 | case EXPR_STMT: |
4325 | case EH_SPEC_BLOCK: | |
cf72f34d | 4326 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 4327 | lval, |
00f21715 | 4328 | non_constant_p, overflow_p, |
4329 | jump_target); | |
09b42213 | 4330 | break; |
4331 | ||
7f67d68c | 4332 | case TRY_FINALLY_EXPR: |
4333 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4334 | non_constant_p, overflow_p, | |
4335 | jump_target); | |
4336 | if (!*non_constant_p) | |
4337 | /* Also evaluate the cleanup. */ | |
4338 | cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), true, | |
4339 | non_constant_p, overflow_p, | |
4340 | jump_target); | |
4341 | break; | |
4342 | ||
09b42213 | 4343 | /* These differ from cxx_eval_unary_expression in that this doesn't |
4344 | check for a constant operand or result; an address can be | |
4345 | constant without its operand being, and vice versa. */ | |
d2c63826 | 4346 | case MEM_REF: |
09b42213 | 4347 | case INDIRECT_REF: |
1227ba74 | 4348 | r = cxx_eval_indirect_ref (ctx, t, lval, |
09b42213 | 4349 | non_constant_p, overflow_p); |
4350 | break; | |
4351 | ||
4352 | case ADDR_EXPR: | |
4353 | { | |
4354 | tree oldop = TREE_OPERAND (t, 0); | |
cf72f34d | 4355 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4356 | /*lval*/true, |
b2a43197 | 4357 | non_constant_p, overflow_p); |
09b42213 | 4358 | /* Don't VERIFY_CONSTANT here. */ |
4359 | if (*non_constant_p) | |
4360 | return t; | |
1eb418cc | 4361 | gcc_checking_assert (TREE_CODE (op) != CONSTRUCTOR); |
09b42213 | 4362 | /* This function does more aggressive folding than fold itself. */ |
4363 | r = build_fold_addr_expr_with_type (op, TREE_TYPE (t)); | |
4364 | if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop) | |
4365 | return t; | |
4366 | break; | |
4367 | } | |
4368 | ||
4369 | case REALPART_EXPR: | |
4370 | case IMAGPART_EXPR: | |
6fe424c2 | 4371 | if (lval) |
4372 | { | |
4373 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4374 | non_constant_p, overflow_p); | |
4375 | if (r == error_mark_node) | |
4376 | ; | |
4377 | else if (r == TREE_OPERAND (t, 0)) | |
4378 | r = t; | |
4379 | else | |
4380 | r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), r); | |
4381 | break; | |
4382 | } | |
4383 | /* FALLTHRU */ | |
09b42213 | 4384 | case CONJ_EXPR: |
4385 | case FIX_TRUNC_EXPR: | |
4386 | case FLOAT_EXPR: | |
4387 | case NEGATE_EXPR: | |
4388 | case ABS_EXPR: | |
4389 | case BIT_NOT_EXPR: | |
4390 | case TRUTH_NOT_EXPR: | |
4391 | case FIXED_CONVERT_EXPR: | |
1227ba74 | 4392 | r = cxx_eval_unary_expression (ctx, t, lval, |
09b42213 | 4393 | non_constant_p, overflow_p); |
4394 | break; | |
4395 | ||
4396 | case SIZEOF_EXPR: | |
d2c63826 | 4397 | r = fold_sizeof_expr (t); |
09b42213 | 4398 | VERIFY_CONSTANT (r); |
4399 | break; | |
4400 | ||
4401 | case COMPOUND_EXPR: | |
4402 | { | |
4403 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
4404 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
4405 | introduced by build_call_a. */ | |
4406 | tree op0 = TREE_OPERAND (t, 0); | |
4407 | tree op1 = TREE_OPERAND (t, 1); | |
4408 | STRIP_NOPS (op1); | |
4409 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
4410 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
f83e6885 | 4411 | r = cxx_eval_constant_expression (ctx, op0, |
1227ba74 | 4412 | lval, non_constant_p, overflow_p, |
00f21715 | 4413 | jump_target); |
09b42213 | 4414 | else |
4415 | { | |
4416 | /* Check that the LHS is constant and then discard it. */ | |
f83e6885 | 4417 | cxx_eval_constant_expression (ctx, op0, |
c8f6aeb1 | 4418 | true, non_constant_p, overflow_p, |
00f21715 | 4419 | jump_target); |
cf03ba19 | 4420 | if (*non_constant_p) |
4421 | return t; | |
09b42213 | 4422 | op1 = TREE_OPERAND (t, 1); |
f83e6885 | 4423 | r = cxx_eval_constant_expression (ctx, op1, |
1227ba74 | 4424 | lval, non_constant_p, overflow_p, |
00f21715 | 4425 | jump_target); |
09b42213 | 4426 | } |
4427 | } | |
4428 | break; | |
4429 | ||
4430 | case POINTER_PLUS_EXPR: | |
57e83b58 | 4431 | case POINTER_DIFF_EXPR: |
09b42213 | 4432 | case PLUS_EXPR: |
4433 | case MINUS_EXPR: | |
4434 | case MULT_EXPR: | |
4435 | case TRUNC_DIV_EXPR: | |
4436 | case CEIL_DIV_EXPR: | |
4437 | case FLOOR_DIV_EXPR: | |
4438 | case ROUND_DIV_EXPR: | |
4439 | case TRUNC_MOD_EXPR: | |
4440 | case CEIL_MOD_EXPR: | |
4441 | case ROUND_MOD_EXPR: | |
4442 | case RDIV_EXPR: | |
4443 | case EXACT_DIV_EXPR: | |
4444 | case MIN_EXPR: | |
4445 | case MAX_EXPR: | |
4446 | case LSHIFT_EXPR: | |
4447 | case RSHIFT_EXPR: | |
4448 | case LROTATE_EXPR: | |
4449 | case RROTATE_EXPR: | |
4450 | case BIT_IOR_EXPR: | |
4451 | case BIT_XOR_EXPR: | |
4452 | case BIT_AND_EXPR: | |
4453 | case TRUTH_XOR_EXPR: | |
4454 | case LT_EXPR: | |
4455 | case LE_EXPR: | |
4456 | case GT_EXPR: | |
4457 | case GE_EXPR: | |
4458 | case EQ_EXPR: | |
4459 | case NE_EXPR: | |
4460 | case UNORDERED_EXPR: | |
4461 | case ORDERED_EXPR: | |
4462 | case UNLT_EXPR: | |
4463 | case UNLE_EXPR: | |
4464 | case UNGT_EXPR: | |
4465 | case UNGE_EXPR: | |
4466 | case UNEQ_EXPR: | |
4467 | case LTGT_EXPR: | |
4468 | case RANGE_EXPR: | |
4469 | case COMPLEX_EXPR: | |
1227ba74 | 4470 | r = cxx_eval_binary_expression (ctx, t, lval, |
09b42213 | 4471 | non_constant_p, overflow_p); |
4472 | break; | |
4473 | ||
4474 | /* fold can introduce non-IF versions of these; still treat them as | |
4475 | short-circuiting. */ | |
4476 | case TRUTH_AND_EXPR: | |
4477 | case TRUTH_ANDIF_EXPR: | |
cf72f34d | 4478 | r = cxx_eval_logical_expression (ctx, t, boolean_false_node, |
09b42213 | 4479 | boolean_true_node, |
1227ba74 | 4480 | lval, |
09b42213 | 4481 | non_constant_p, overflow_p); |
4482 | break; | |
4483 | ||
4484 | case TRUTH_OR_EXPR: | |
4485 | case TRUTH_ORIF_EXPR: | |
cf72f34d | 4486 | r = cxx_eval_logical_expression (ctx, t, boolean_true_node, |
09b42213 | 4487 | boolean_false_node, |
1227ba74 | 4488 | lval, |
09b42213 | 4489 | non_constant_p, overflow_p); |
4490 | break; | |
4491 | ||
4492 | case ARRAY_REF: | |
1227ba74 | 4493 | r = cxx_eval_array_reference (ctx, t, lval, |
09b42213 | 4494 | non_constant_p, overflow_p); |
4495 | break; | |
4496 | ||
4497 | case COMPONENT_REF: | |
4498 | if (is_overloaded_fn (t)) | |
4499 | { | |
4500 | /* We can only get here in checking mode via | |
4501 | build_non_dependent_expr, because any expression that | |
4502 | calls or takes the address of the function will have | |
4503 | pulled a FUNCTION_DECL out of the COMPONENT_REF. */ | |
f83e6885 | 4504 | gcc_checking_assert (ctx->quiet || errorcount); |
09b42213 | 4505 | *non_constant_p = true; |
4506 | return t; | |
4507 | } | |
1227ba74 | 4508 | r = cxx_eval_component_reference (ctx, t, lval, |
09b42213 | 4509 | non_constant_p, overflow_p); |
4510 | break; | |
4511 | ||
4512 | case BIT_FIELD_REF: | |
1227ba74 | 4513 | r = cxx_eval_bit_field_ref (ctx, t, lval, |
09b42213 | 4514 | non_constant_p, overflow_p); |
4515 | break; | |
4516 | ||
4517 | case COND_EXPR: | |
2a2770c6 | 4518 | if (jump_target && *jump_target) |
4519 | { | |
4520 | /* When jumping to a label, the label might be either in the | |
4521 | then or else blocks, so process then block first in skipping | |
4522 | mode first, and if we are still in the skipping mode at its end, | |
4523 | process the else block too. */ | |
4524 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
4525 | lval, non_constant_p, overflow_p, | |
4526 | jump_target); | |
4527 | if (*jump_target) | |
4528 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
4529 | lval, non_constant_p, overflow_p, | |
4530 | jump_target); | |
4531 | break; | |
4532 | } | |
1227ba74 | 4533 | r = cxx_eval_conditional_expression (ctx, t, lval, |
00f21715 | 4534 | non_constant_p, overflow_p, |
4535 | jump_target); | |
09b42213 | 4536 | break; |
31595caf | 4537 | case VEC_COND_EXPR: |
4538 | r = cxx_eval_vector_conditional_expression (ctx, t, non_constant_p, | |
4539 | overflow_p); | |
4540 | break; | |
09b42213 | 4541 | |
4542 | case CONSTRUCTOR: | |
1a3631bc | 4543 | if (TREE_CONSTANT (t)) |
58b0f9ce | 4544 | { |
4545 | /* Don't re-process a constant CONSTRUCTOR, but do fold it to | |
4546 | VECTOR_CST if applicable. */ | |
79e65a6b | 4547 | verify_constructor_flags (t); |
58b0f9ce | 4548 | if (TREE_CONSTANT (t)) |
4549 | return fold (t); | |
4550 | } | |
1227ba74 | 4551 | r = cxx_eval_bare_aggregate (ctx, t, lval, |
09b42213 | 4552 | non_constant_p, overflow_p); |
4553 | break; | |
4554 | ||
4555 | case VEC_INIT_EXPR: | |
4556 | /* We can get this in a defaulted constructor for a class with a | |
4557 | non-static data member of array type. Either the initializer will | |
4558 | be NULL, meaning default-initialization, or it will be an lvalue | |
4559 | or xvalue of the same type, meaning direct-initialization from the | |
4560 | corresponding member. */ | |
1227ba74 | 4561 | r = cxx_eval_vec_init (ctx, t, lval, |
09b42213 | 4562 | non_constant_p, overflow_p); |
4563 | break; | |
4564 | ||
4565 | case FMA_EXPR: | |
4566 | case VEC_PERM_EXPR: | |
1227ba74 | 4567 | r = cxx_eval_trinary_expression (ctx, t, lval, |
09b42213 | 4568 | non_constant_p, overflow_p); |
4569 | break; | |
4570 | ||
4571 | case CONVERT_EXPR: | |
4572 | case VIEW_CONVERT_EXPR: | |
4573 | case NOP_EXPR: | |
d2c63826 | 4574 | case UNARY_PLUS_EXPR: |
09b42213 | 4575 | { |
4576 | tree oldop = TREE_OPERAND (t, 0); | |
d2c63826 | 4577 | |
cf72f34d | 4578 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4579 | lval, |
b2a43197 | 4580 | non_constant_p, overflow_p); |
09b42213 | 4581 | if (*non_constant_p) |
4582 | return t; | |
f16ed232 | 4583 | tree type = TREE_TYPE (t); |
4584 | if (TREE_CODE (op) == PTRMEM_CST | |
4585 | && !TYPE_PTRMEM_P (type)) | |
4586 | op = cplus_expand_constant (op); | |
6a9b35ef | 4587 | if (TREE_CODE (op) == PTRMEM_CST && tcode == NOP_EXPR) |
4588 | { | |
4589 | if (same_type_ignoring_top_level_qualifiers_p (type, | |
0a8a2108 | 4590 | TREE_TYPE (op)) |
4591 | || can_convert_qual (type, op)) | |
19d56e62 | 4592 | return cp_fold_convert (type, op); |
6a9b35ef | 4593 | else |
4594 | { | |
4595 | if (!ctx->quiet) | |
4596 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
ea034e2c | 4597 | "a reinterpret_cast is not a constant expression"); |
6a9b35ef | 4598 | *non_constant_p = true; |
4599 | return t; | |
4600 | } | |
4601 | } | |
cb768824 | 4602 | |
4603 | if (POINTER_TYPE_P (type) && TREE_CODE (op) == INTEGER_CST) | |
09b42213 | 4604 | { |
cb768824 | 4605 | if (integer_zerop (op)) |
4606 | { | |
4607 | if (TREE_CODE (type) == REFERENCE_TYPE) | |
4608 | { | |
4609 | if (!ctx->quiet) | |
4610 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4611 | "dereferencing a null pointer"); | |
4612 | *non_constant_p = true; | |
4613 | return t; | |
4614 | } | |
4615 | else if (TREE_CODE (TREE_TYPE (op)) == POINTER_TYPE) | |
4616 | { | |
4617 | tree from = TREE_TYPE (op); | |
4618 | ||
4619 | if (!can_convert (type, from, tf_none)) | |
4620 | { | |
4621 | if (!ctx->quiet) | |
4622 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4623 | "conversion of %qT null pointer to %qT " | |
4624 | "is not a constant expression", | |
4625 | from, type); | |
4626 | *non_constant_p = true; | |
4627 | return t; | |
4628 | } | |
4629 | } | |
4630 | } | |
4631 | else | |
4632 | { | |
4633 | /* This detects for example: | |
4634 | reinterpret_cast<void*>(sizeof 0) | |
4635 | */ | |
4636 | if (!ctx->quiet) | |
4637 | error_at (EXPR_LOC_OR_LOC (t, input_location), | |
4638 | "%<reinterpret_cast<%T>(%E)%> is not " | |
ea034e2c | 4639 | "a constant expression", |
cb768824 | 4640 | type, op); |
4641 | *non_constant_p = true; | |
4642 | return t; | |
4643 | } | |
09b42213 | 4644 | } |
d2c63826 | 4645 | if (op == oldop && tcode != UNARY_PLUS_EXPR) |
09b42213 | 4646 | /* We didn't fold at the top so we could check for ptr-int |
4647 | conversion. */ | |
4648 | return fold (t); | |
d2c63826 | 4649 | if (tcode == UNARY_PLUS_EXPR) |
4650 | r = fold_convert (TREE_TYPE (t), op); | |
4651 | else | |
4652 | r = fold_build1 (tcode, type, op); | |
09b42213 | 4653 | /* Conversion of an out-of-range value has implementation-defined |
4654 | behavior; the language considers it different from arithmetic | |
4655 | overflow, which is undefined. */ | |
4656 | if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op)) | |
4657 | TREE_OVERFLOW (r) = false; | |
4658 | } | |
4659 | break; | |
4660 | ||
4661 | case EMPTY_CLASS_EXPR: | |
4662 | /* This is good enough for a function argument that might not get | |
4663 | used, and they can't do anything with it, so just return it. */ | |
4664 | return t; | |
4665 | ||
9c96033c | 4666 | case STATEMENT_LIST: |
00f21715 | 4667 | new_ctx = *ctx; |
4668 | new_ctx.ctor = new_ctx.object = NULL_TREE; | |
f83e6885 | 4669 | return cxx_eval_statement_list (&new_ctx, t, |
00f21715 | 4670 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4671 | |
4672 | case BIND_EXPR: | |
4673 | return cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t), | |
1227ba74 | 4674 | lval, |
00f21715 | 4675 | non_constant_p, overflow_p, |
4676 | jump_target); | |
9c96033c | 4677 | |
09b42213 | 4678 | case PREINCREMENT_EXPR: |
4679 | case POSTINCREMENT_EXPR: | |
4680 | case PREDECREMENT_EXPR: | |
4681 | case POSTDECREMENT_EXPR: | |
f83e6885 | 4682 | return cxx_eval_increment_expression (ctx, t, |
1227ba74 | 4683 | lval, non_constant_p, overflow_p); |
9c96033c | 4684 | |
4685 | case LAMBDA_EXPR: | |
09b42213 | 4686 | case NEW_EXPR: |
4687 | case VEC_NEW_EXPR: | |
4688 | case DELETE_EXPR: | |
4689 | case VEC_DELETE_EXPR: | |
4690 | case THROW_EXPR: | |
09b42213 | 4691 | case MODOP_EXPR: |
4692 | /* GCC internal stuff. */ | |
4693 | case VA_ARG_EXPR: | |
4694 | case OBJ_TYPE_REF: | |
09b42213 | 4695 | case NON_DEPENDENT_EXPR: |
4696 | case BASELINK: | |
09b42213 | 4697 | case OFFSET_REF: |
f83e6885 | 4698 | if (!ctx->quiet) |
09b42213 | 4699 | error_at (EXPR_LOC_OR_LOC (t, input_location), |
ea034e2c | 4700 | "expression %qE is not a constant expression", t); |
09b42213 | 4701 | *non_constant_p = true; |
4702 | break; | |
4703 | ||
cf72f34d | 4704 | case PLACEHOLDER_EXPR: |
85de9604 | 4705 | /* Use of the value or address of the current object. */ |
4706 | if (tree ctor = lookup_placeholder (ctx, lval, TREE_TYPE (t))) | |
4707 | return cxx_eval_constant_expression (ctx, ctor, lval, | |
4708 | non_constant_p, overflow_p); | |
4709 | /* A placeholder without a referent. We can get here when | |
4710 | checking whether NSDMIs are noexcept, or in massage_init_elt; | |
4711 | just say it's non-constant for now. */ | |
4712 | gcc_assert (ctx->quiet); | |
4713 | *non_constant_p = true; | |
cf72f34d | 4714 | break; |
4715 | ||
cf03ba19 | 4716 | case EXIT_EXPR: |
4717 | { | |
4718 | tree cond = TREE_OPERAND (t, 0); | |
4719 | cond = cxx_eval_constant_expression (ctx, cond, /*lval*/false, | |
4720 | non_constant_p, overflow_p); | |
4721 | VERIFY_CONSTANT (cond); | |
4722 | if (integer_nonzerop (cond)) | |
4723 | *jump_target = t; | |
4724 | } | |
4725 | break; | |
4726 | ||
9c96033c | 4727 | case GOTO_EXPR: |
00f21715 | 4728 | *jump_target = TREE_OPERAND (t, 0); |
d29e4e8c | 4729 | gcc_assert (breaks (jump_target) || continues (jump_target) |
4730 | /* Allow for jumping to a cdtor_label. */ | |
4731 | || returns (jump_target)); | |
00f21715 | 4732 | break; |
4733 | ||
9c96033c | 4734 | case LOOP_EXPR: |
f83e6885 | 4735 | cxx_eval_loop_expr (ctx, t, |
00f21715 | 4736 | non_constant_p, overflow_p, jump_target); |
4737 | break; | |
4738 | ||
9c96033c | 4739 | case SWITCH_EXPR: |
f83e6885 | 4740 | cxx_eval_switch_expr (ctx, t, |
00f21715 | 4741 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4742 | break; |
4743 | ||
56c12fd4 | 4744 | case REQUIRES_EXPR: |
4745 | /* It's possible to get a requires-expression in a constant | |
4746 | expression. For example: | |
4747 | ||
4748 | template<typename T> concept bool C() { | |
4749 | return requires (T t) { t; }; | |
4750 | } | |
4751 | ||
4752 | template<typename T> requires !C<T>() void f(T); | |
4753 | ||
4754 | Normalization leaves f with the associated constraint | |
4755 | '!requires (T t) { ... }' which is not transformed into | |
4756 | a constraint. */ | |
4757 | if (!processing_template_decl) | |
4758 | return evaluate_constraint_expression (t, NULL_TREE); | |
4759 | else | |
4760 | *non_constant_p = true; | |
4761 | return t; | |
4762 | ||
24c6ee98 | 4763 | case ANNOTATE_EXPR: |
24c6ee98 | 4764 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
4765 | lval, | |
4766 | non_constant_p, overflow_p, | |
4767 | jump_target); | |
4768 | break; | |
4769 | ||
7285637a | 4770 | case USING_STMT: |
4771 | r = void_node; | |
4772 | break; | |
4773 | ||
09b42213 | 4774 | default: |
b9a3af23 | 4775 | if (STATEMENT_CODE_P (TREE_CODE (t))) |
4776 | { | |
4777 | /* This function doesn't know how to deal with pre-genericize | |
4778 | statements; this can only happen with statement-expressions, | |
4779 | so for now just fail. */ | |
4780 | if (!ctx->quiet) | |
4781 | error_at (EXPR_LOCATION (t), | |
ea034e2c | 4782 | "statement is not a constant expression"); |
b9a3af23 | 4783 | } |
4784 | else | |
4785 | internal_error ("unexpected expression %qE of kind %s", t, | |
4786 | get_tree_code_name (TREE_CODE (t))); | |
09b42213 | 4787 | *non_constant_p = true; |
4788 | break; | |
4789 | } | |
4790 | ||
4791 | if (r == error_mark_node) | |
4792 | *non_constant_p = true; | |
4793 | ||
4794 | if (*non_constant_p) | |
4795 | return t; | |
4796 | else | |
4797 | return r; | |
4798 | } | |
4799 | ||
4800 | static tree | |
cf72f34d | 4801 | cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, |
2055d27a | 4802 | bool strict = true, tree object = NULL_TREE) |
09b42213 | 4803 | { |
c300fe28 | 4804 | auto_timevar time (TV_CONSTEXPR); |
4805 | ||
09b42213 | 4806 | bool non_constant_p = false; |
4807 | bool overflow_p = false; | |
cf72f34d | 4808 | hash_map<tree,tree> map; |
2631cb67 | 4809 | |
2a2770c6 | 4810 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, NULL, NULL, |
2631cb67 | 4811 | allow_non_constant, strict }; |
4812 | ||
cf72f34d | 4813 | tree type = initialized_type (t); |
cf72f34d | 4814 | tree r = t; |
4815 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) | |
4816 | { | |
4817 | /* In C++14 an NSDMI can participate in aggregate initialization, | |
4818 | and can refer to the address of the object being initialized, so | |
4819 | we need to pass in the relevant VAR_DECL if we want to do the | |
4820 | evaluation in a single pass. The evaluation will dynamically | |
4821 | update ctx.values for the VAR_DECL. We use the same strategy | |
4822 | for C++11 constexpr constructors that refer to the object being | |
4823 | initialized. */ | |
4824 | ctx.ctor = build_constructor (type, NULL); | |
4825 | CONSTRUCTOR_NO_IMPLICIT_ZERO (ctx.ctor) = true; | |
9c96033c | 4826 | if (!object) |
4827 | { | |
4828 | if (TREE_CODE (t) == TARGET_EXPR) | |
4829 | object = TARGET_EXPR_SLOT (t); | |
4830 | else if (TREE_CODE (t) == AGGR_INIT_EXPR) | |
4831 | object = AGGR_INIT_EXPR_SLOT (t); | |
4832 | } | |
cf72f34d | 4833 | ctx.object = object; |
4834 | if (object) | |
4835 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
4836 | (type, TREE_TYPE (object))); | |
4837 | if (object && DECL_P (object)) | |
4838 | map.put (object, ctx.ctor); | |
4839 | if (TREE_CODE (r) == TARGET_EXPR) | |
4840 | /* Avoid creating another CONSTRUCTOR when we expand the | |
4841 | TARGET_EXPR. */ | |
4842 | r = TARGET_EXPR_INITIAL (r); | |
4843 | } | |
4844 | ||
f83e6885 | 4845 | r = cxx_eval_constant_expression (&ctx, r, |
b2a43197 | 4846 | false, &non_constant_p, &overflow_p); |
09b42213 | 4847 | |
4848 | verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); | |
4849 | ||
bbcc9042 | 4850 | /* Mutable logic is a bit tricky: we want to allow initialization of |
4851 | constexpr variables with mutable members, but we can't copy those | |
4852 | members to another constexpr variable. */ | |
4853 | if (TREE_CODE (r) == CONSTRUCTOR | |
4854 | && CONSTRUCTOR_MUTABLE_POISON (r)) | |
09b42213 | 4855 | { |
09b42213 | 4856 | if (!allow_non_constant) |
bbcc9042 | 4857 | error ("%qE is not a constant expression because it refers to " |
4858 | "mutable subobjects of %qT", t, type); | |
09b42213 | 4859 | non_constant_p = true; |
4860 | } | |
4861 | ||
c6d97004 | 4862 | if (TREE_CODE (r) == CONSTRUCTOR |
4863 | && CONSTRUCTOR_NO_IMPLICIT_ZERO (r)) | |
4864 | { | |
4865 | if (!allow_non_constant) | |
4866 | error ("%qE is not a constant expression because it refers to " | |
4867 | "an incompletely initialized variable", t); | |
4868 | TREE_CONSTANT (r) = false; | |
4869 | non_constant_p = true; | |
4870 | } | |
4871 | ||
09b42213 | 4872 | /* Technically we should check this for all subexpressions, but that |
4873 | runs into problems with our internal representation of pointer | |
4874 | subtraction and the 5.19 rules are still in flux. */ | |
4875 | if (CONVERT_EXPR_CODE_P (TREE_CODE (r)) | |
4876 | && ARITHMETIC_TYPE_P (TREE_TYPE (r)) | |
4877 | && TREE_CODE (TREE_OPERAND (r, 0)) == ADDR_EXPR) | |
4878 | { | |
4879 | if (!allow_non_constant) | |
4880 | error ("conversion from pointer type %qT " | |
ea034e2c | 4881 | "to arithmetic type %qT in a constant expression", |
09b42213 | 4882 | TREE_TYPE (TREE_OPERAND (r, 0)), TREE_TYPE (r)); |
4883 | non_constant_p = true; | |
4884 | } | |
4885 | ||
4886 | if (!non_constant_p && overflow_p) | |
4887 | non_constant_p = true; | |
4888 | ||
c6c0523b | 4889 | /* Unshare the result unless it's a CONSTRUCTOR in which case it's already |
4890 | unshared. */ | |
4891 | bool should_unshare = true; | |
4892 | if (r == t || TREE_CODE (r) == CONSTRUCTOR) | |
4893 | should_unshare = false; | |
4894 | ||
09b42213 | 4895 | if (non_constant_p && !allow_non_constant) |
4896 | return error_mark_node; | |
4897 | else if (non_constant_p && TREE_CONSTANT (r)) | |
4898 | { | |
1d29f4ea | 4899 | /* This isn't actually constant, so unset TREE_CONSTANT. |
4900 | Don't clear TREE_CONSTANT on ADDR_EXPR, as the middle-end requires | |
4901 | it to be set if it is invariant address, even when it is not | |
4902 | a valid C++ constant expression. Wrap it with a NOP_EXPR | |
4903 | instead. */ | |
4904 | if (EXPR_P (r) && TREE_CODE (r) != ADDR_EXPR) | |
09b42213 | 4905 | r = copy_node (r); |
4906 | else if (TREE_CODE (r) == CONSTRUCTOR) | |
4907 | r = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (r), r); | |
4908 | else | |
4909 | r = build_nop (TREE_TYPE (r), r); | |
4910 | TREE_CONSTANT (r) = false; | |
4911 | } | |
4912 | else if (non_constant_p || r == t) | |
4913 | return t; | |
4914 | ||
c6c0523b | 4915 | if (should_unshare) |
4916 | r = unshare_expr (r); | |
4917 | ||
09b42213 | 4918 | if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r))) |
4919 | { | |
4920 | if (TREE_CODE (t) == TARGET_EXPR | |
4921 | && TARGET_EXPR_INITIAL (t) == r) | |
4922 | return t; | |
4923 | else | |
4924 | { | |
4925 | r = get_target_expr (r); | |
4926 | TREE_CONSTANT (r) = true; | |
4927 | return r; | |
4928 | } | |
4929 | } | |
4930 | else | |
4931 | return r; | |
4932 | } | |
4933 | ||
4934 | /* Returns true if T is a valid subexpression of a constant expression, | |
4935 | even if it isn't itself a constant expression. */ | |
4936 | ||
4937 | bool | |
4938 | is_sub_constant_expr (tree t) | |
4939 | { | |
4940 | bool non_constant_p = false; | |
4941 | bool overflow_p = false; | |
cf72f34d | 4942 | hash_map <tree, tree> map; |
2631cb67 | 4943 | |
2a2770c6 | 4944 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, NULL, NULL, true, true }; |
2631cb67 | 4945 | |
f83e6885 | 4946 | cxx_eval_constant_expression (&ctx, t, false, &non_constant_p, |
b2a43197 | 4947 | &overflow_p); |
09b42213 | 4948 | return !non_constant_p && !overflow_p; |
4949 | } | |
4950 | ||
4951 | /* If T represents a constant expression returns its reduced value. | |
4952 | Otherwise return error_mark_node. If T is dependent, then | |
4953 | return NULL. */ | |
4954 | ||
4955 | tree | |
cf72f34d | 4956 | cxx_constant_value (tree t, tree decl) |
09b42213 | 4957 | { |
2055d27a | 4958 | return cxx_eval_outermost_constant_expr (t, false, true, decl); |
09b42213 | 4959 | } |
4960 | ||
d2c63826 | 4961 | /* Helper routine for fold_simple function. Either return simplified |
4962 | expression T, otherwise NULL_TREE. | |
4963 | In contrast to cp_fully_fold, and to maybe_constant_value, we try to fold | |
4964 | even if we are within template-declaration. So be careful on call, as in | |
4965 | such case types can be undefined. */ | |
4966 | ||
4967 | static tree | |
4968 | fold_simple_1 (tree t) | |
4969 | { | |
4970 | tree op1; | |
4971 | enum tree_code code = TREE_CODE (t); | |
4972 | ||
4973 | switch (code) | |
4974 | { | |
4975 | case INTEGER_CST: | |
4976 | case REAL_CST: | |
4977 | case VECTOR_CST: | |
4978 | case FIXED_CST: | |
4979 | case COMPLEX_CST: | |
4980 | return t; | |
4981 | ||
4982 | case SIZEOF_EXPR: | |
4983 | return fold_sizeof_expr (t); | |
4984 | ||
4985 | case ABS_EXPR: | |
4986 | case CONJ_EXPR: | |
4987 | case REALPART_EXPR: | |
4988 | case IMAGPART_EXPR: | |
4989 | case NEGATE_EXPR: | |
4990 | case BIT_NOT_EXPR: | |
4991 | case TRUTH_NOT_EXPR: | |
4992 | case NOP_EXPR: | |
4993 | case VIEW_CONVERT_EXPR: | |
4994 | case CONVERT_EXPR: | |
4995 | case FLOAT_EXPR: | |
4996 | case FIX_TRUNC_EXPR: | |
4997 | case FIXED_CONVERT_EXPR: | |
4998 | case ADDR_SPACE_CONVERT_EXPR: | |
4999 | ||
5000 | op1 = TREE_OPERAND (t, 0); | |
5001 | ||
5002 | t = const_unop (code, TREE_TYPE (t), op1); | |
5003 | if (!t) | |
5004 | return NULL_TREE; | |
5005 | ||
5006 | if (CONVERT_EXPR_CODE_P (code) | |
5007 | && TREE_OVERFLOW_P (t) && !TREE_OVERFLOW_P (op1)) | |
5008 | TREE_OVERFLOW (t) = false; | |
5009 | return t; | |
5010 | ||
5011 | default: | |
5012 | return NULL_TREE; | |
5013 | } | |
5014 | } | |
5015 | ||
5016 | /* If T is a simple constant expression, returns its simplified value. | |
6fe5fea9 | 5017 | Otherwise returns T. In contrast to maybe_constant_value we |
d2c63826 | 5018 | simplify only few operations on constant-expressions, and we don't |
5019 | try to simplify constexpressions. */ | |
5020 | ||
5021 | tree | |
5022 | fold_simple (tree t) | |
5023 | { | |
d2c63826 | 5024 | if (processing_template_decl) |
5025 | return t; | |
5026 | ||
6fe5fea9 | 5027 | tree r = fold_simple_1 (t); |
5028 | if (r) | |
5029 | return r; | |
d2c63826 | 5030 | |
6fe5fea9 | 5031 | return t; |
d2c63826 | 5032 | } |
5033 | ||
09b42213 | 5034 | /* If T is a constant expression, returns its reduced value. |
5035 | Otherwise, if T does not have TREE_CONSTANT set, returns T. | |
5036 | Otherwise, returns a version of T without TREE_CONSTANT. */ | |
5037 | ||
b601ad30 | 5038 | static GTY((deletable)) hash_map<tree, tree> *cv_cache; |
5039 | ||
5040 | tree | |
5041 | maybe_constant_value (tree t, tree decl) | |
09b42213 | 5042 | { |
5043 | tree r; | |
5044 | ||
7e1f8be4 | 5045 | if (!is_nondependent_constant_expression (t)) |
09b42213 | 5046 | { |
5047 | if (TREE_OVERFLOW_P (t)) | |
5048 | { | |
5049 | t = build_nop (TREE_TYPE (t), t); | |
5050 | TREE_CONSTANT (t) = false; | |
5051 | } | |
5052 | return t; | |
5053 | } | |
b601ad30 | 5054 | else if (CONSTANT_CLASS_P (t)) |
5055 | /* No caching or evaluation needed. */ | |
5056 | return t; | |
5057 | ||
5058 | if (cv_cache == NULL) | |
5059 | cv_cache = hash_map<tree, tree>::create_ggc (101); | |
5060 | if (tree *cached = cv_cache->get (t)) | |
5061 | return *cached; | |
09b42213 | 5062 | |
2055d27a | 5063 | r = cxx_eval_outermost_constant_expr (t, true, true, decl); |
5e8689fb | 5064 | gcc_checking_assert (r == t |
5065 | || CONVERT_EXPR_P (t) | |
5066 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
5067 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
5068 | || !cp_tree_equal (r, t)); | |
b601ad30 | 5069 | cv_cache->put (t, r); |
09b42213 | 5070 | return r; |
5071 | } | |
5072 | ||
2a655a4c | 5073 | /* Dispose of the whole CV_CACHE. */ |
5074 | ||
5075 | static void | |
5076 | clear_cv_cache (void) | |
5077 | { | |
5078 | if (cv_cache != NULL) | |
5079 | cv_cache->empty (); | |
5080 | } | |
5081 | ||
f553d9f8 | 5082 | /* Dispose of the whole CV_CACHE and FOLD_CACHE. */ |
a0c919f7 | 5083 | |
5084 | void | |
f553d9f8 | 5085 | clear_cv_and_fold_caches (void) |
a0c919f7 | 5086 | { |
2a655a4c | 5087 | clear_cv_cache (); |
f553d9f8 | 5088 | clear_fold_cache (); |
a0c919f7 | 5089 | } |
5090 | ||
21131a05 | 5091 | /* Like maybe_constant_value but first fully instantiate the argument. |
5092 | ||
5093 | Note: this is equivalent to instantiate_non_dependent_expr_sfinae | |
5094 | (t, tf_none) followed by maybe_constant_value but is more efficient, | |
5095 | because calls instantiation_dependent_expression_p and | |
5096 | potential_constant_expression at most once. */ | |
5097 | ||
5098 | tree | |
5099 | fold_non_dependent_expr (tree t) | |
5100 | { | |
5101 | if (t == NULL_TREE) | |
5102 | return NULL_TREE; | |
5103 | ||
5104 | /* If we're in a template, but T isn't value dependent, simplify | |
5105 | it. We're supposed to treat: | |
5106 | ||
5107 | template <typename T> void f(T[1 + 1]); | |
5108 | template <typename T> void f(T[2]); | |
5109 | ||
5110 | as two declarations of the same function, for example. */ | |
5111 | if (processing_template_decl) | |
5112 | { | |
7e1f8be4 | 5113 | if (is_nondependent_constant_expression (t)) |
21131a05 | 5114 | { |
c8a9f04c | 5115 | processing_template_decl_sentinel s; |
5116 | t = instantiate_non_dependent_expr_internal (t, tf_none); | |
21131a05 | 5117 | |
5118 | if (type_unknown_p (t) | |
5119 | || BRACE_ENCLOSED_INITIALIZER_P (t)) | |
5120 | { | |
5121 | if (TREE_OVERFLOW_P (t)) | |
5122 | { | |
5123 | t = build_nop (TREE_TYPE (t), t); | |
5124 | TREE_CONSTANT (t) = false; | |
5125 | } | |
5126 | return t; | |
5127 | } | |
5128 | ||
2055d27a | 5129 | tree r = cxx_eval_outermost_constant_expr (t, true, true, NULL_TREE); |
21131a05 | 5130 | /* cp_tree_equal looks through NOPs, so allow them. */ |
5e8689fb | 5131 | gcc_checking_assert (r == t |
5132 | || CONVERT_EXPR_P (t) | |
5133 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
5134 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
5135 | || !cp_tree_equal (r, t)); | |
21131a05 | 5136 | return r; |
5137 | } | |
5138 | else if (TREE_OVERFLOW_P (t)) | |
5139 | { | |
5140 | t = build_nop (TREE_TYPE (t), t); | |
5141 | TREE_CONSTANT (t) = false; | |
5142 | } | |
5143 | return t; | |
5144 | } | |
5145 | ||
5146 | return maybe_constant_value (t); | |
5147 | } | |
5148 | ||
09b42213 | 5149 | /* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather |
5150 | than wrapped in a TARGET_EXPR. */ | |
5151 | ||
0c703e14 | 5152 | static tree |
5153 | maybe_constant_init_1 (tree t, tree decl, bool allow_non_constant) | |
09b42213 | 5154 | { |
d2c63826 | 5155 | if (!t) |
5156 | return t; | |
09b42213 | 5157 | if (TREE_CODE (t) == EXPR_STMT) |
5158 | t = TREE_OPERAND (t, 0); | |
5159 | if (TREE_CODE (t) == CONVERT_EXPR | |
5160 | && VOID_TYPE_P (TREE_TYPE (t))) | |
5161 | t = TREE_OPERAND (t, 0); | |
9c96033c | 5162 | if (TREE_CODE (t) == INIT_EXPR) |
5163 | t = TREE_OPERAND (t, 1); | |
c6d97004 | 5164 | if (TREE_CODE (t) == TARGET_EXPR) |
5165 | t = TARGET_EXPR_INITIAL (t); | |
7e1f8be4 | 5166 | if (!is_nondependent_static_init_expression (t)) |
2055d27a | 5167 | /* Don't try to evaluate it. */; |
0c703e14 | 5168 | else if (CONSTANT_CLASS_P (t) && allow_non_constant) |
b601ad30 | 5169 | /* No evaluation needed. */; |
2055d27a | 5170 | else |
0c703e14 | 5171 | t = cxx_eval_outermost_constant_expr (t, allow_non_constant, false, decl); |
09b42213 | 5172 | if (TREE_CODE (t) == TARGET_EXPR) |
5173 | { | |
5174 | tree init = TARGET_EXPR_INITIAL (t); | |
5175 | if (TREE_CODE (init) == CONSTRUCTOR) | |
5176 | t = init; | |
5177 | } | |
5178 | return t; | |
5179 | } | |
5180 | ||
0c703e14 | 5181 | /* Wrapper for maybe_constant_init_1 which permits non constants. */ |
5182 | ||
5183 | tree | |
5184 | maybe_constant_init (tree t, tree decl) | |
5185 | { | |
5186 | return maybe_constant_init_1 (t, decl, true); | |
5187 | } | |
5188 | ||
5189 | /* Wrapper for maybe_constant_init_1 which does not permit non constants. */ | |
5190 | ||
5191 | tree | |
5192 | cxx_constant_init (tree t, tree decl) | |
5193 | { | |
5194 | return maybe_constant_init_1 (t, decl, false); | |
5195 | } | |
5196 | ||
09b42213 | 5197 | #if 0 |
5198 | /* FIXME see ADDR_EXPR section in potential_constant_expression_1. */ | |
5199 | /* Return true if the object referred to by REF has automatic or thread | |
5200 | local storage. */ | |
5201 | ||
5202 | enum { ck_ok, ck_bad, ck_unknown }; | |
5203 | static int | |
5204 | check_automatic_or_tls (tree ref) | |
5205 | { | |
3754d046 | 5206 | machine_mode mode; |
81bc0f0f | 5207 | poly_int64 bitsize, bitpos; |
09b42213 | 5208 | tree offset; |
5209 | int volatilep = 0, unsignedp = 0; | |
5210 | tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset, | |
5211 | &mode, &unsignedp, &volatilep, false); | |
5212 | duration_kind dk; | |
5213 | ||
5214 | /* If there isn't a decl in the middle, we don't know the linkage here, | |
5215 | and this isn't a constant expression anyway. */ | |
5216 | if (!DECL_P (decl)) | |
5217 | return ck_unknown; | |
5218 | dk = decl_storage_duration (decl); | |
5219 | return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok; | |
5220 | } | |
5221 | #endif | |
5222 | ||
5223 | /* Return true if T denotes a potentially constant expression. Issue | |
5224 | diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true, | |
7e1f8be4 | 5225 | an lvalue-rvalue conversion is implied. If NOW is true, we want to |
5226 | consider the expression in the current context, independent of constexpr | |
5227 | substitution. | |
09b42213 | 5228 | |
5229 | C++0x [expr.const] used to say | |
5230 | ||
5231 | 6 An expression is a potential constant expression if it is | |
5232 | a constant expression where all occurrences of function | |
5233 | parameters are replaced by arbitrary constant expressions | |
5234 | of the appropriate type. | |
5235 | ||
5236 | 2 A conditional expression is a constant expression unless it | |
5237 | involves one of the following as a potentially evaluated | |
5238 | subexpression (3.2), but subexpressions of logical AND (5.14), | |
5239 | logical OR (5.15), and conditional (5.16) operations that are | |
5240 | not evaluated are not considered. */ | |
5241 | ||
5242 | static bool | |
7e1f8be4 | 5243 | potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, |
2055d27a | 5244 | tsubst_flags_t flags) |
09b42213 | 5245 | { |
7e1f8be4 | 5246 | #define RECUR(T,RV) \ |
5247 | potential_constant_expression_1 ((T), (RV), strict, now, flags) | |
5248 | ||
09b42213 | 5249 | enum { any = false, rval = true }; |
5250 | int i; | |
5251 | tree tmp; | |
5252 | ||
5253 | if (t == error_mark_node) | |
5254 | return false; | |
5255 | if (t == NULL_TREE) | |
5256 | return true; | |
d6a08f5c | 5257 | location_t loc = EXPR_LOC_OR_LOC (t, input_location); |
eade0940 | 5258 | if (TREE_THIS_VOLATILE (t) && !DECL_P (t)) |
09b42213 | 5259 | { |
5260 | if (flags & tf_error) | |
d6a08f5c | 5261 | error_at (loc, "expression %qE has side-effects", t); |
09b42213 | 5262 | return false; |
5263 | } | |
5264 | if (CONSTANT_CLASS_P (t)) | |
5265 | return true; | |
c7282bf2 | 5266 | if (CODE_CONTAINS_STRUCT (TREE_CODE (t), TS_TYPED) |
5267 | && TREE_TYPE (t) == error_mark_node) | |
5268 | return false; | |
09b42213 | 5269 | |
5270 | switch (TREE_CODE (t)) | |
5271 | { | |
5272 | case FUNCTION_DECL: | |
5273 | case BASELINK: | |
5274 | case TEMPLATE_DECL: | |
5275 | case OVERLOAD: | |
5276 | case TEMPLATE_ID_EXPR: | |
5277 | case LABEL_DECL: | |
5278 | case LABEL_EXPR: | |
9c96033c | 5279 | case CASE_LABEL_EXPR: |
09b42213 | 5280 | case CONST_DECL: |
5281 | case SIZEOF_EXPR: | |
5282 | case ALIGNOF_EXPR: | |
5283 | case OFFSETOF_EXPR: | |
5284 | case NOEXCEPT_EXPR: | |
5285 | case TEMPLATE_PARM_INDEX: | |
5286 | case TRAIT_EXPR: | |
5287 | case IDENTIFIER_NODE: | |
5288 | case USERDEF_LITERAL: | |
5289 | /* We can see a FIELD_DECL in a pointer-to-member expression. */ | |
5290 | case FIELD_DECL: | |
d2c63826 | 5291 | case RESULT_DECL: |
09b42213 | 5292 | case USING_DECL: |
9c96033c | 5293 | case USING_STMT: |
cf72f34d | 5294 | case PLACEHOLDER_EXPR: |
9c96033c | 5295 | case BREAK_STMT: |
5296 | case CONTINUE_STMT: | |
56c12fd4 | 5297 | case REQUIRES_EXPR: |
33603066 | 5298 | case STATIC_ASSERT: |
90567983 | 5299 | case DEBUG_BEGIN_STMT: |
09b42213 | 5300 | return true; |
5301 | ||
7e1f8be4 | 5302 | case PARM_DECL: |
5303 | if (now) | |
5304 | { | |
5305 | if (flags & tf_error) | |
5306 | error ("%qE is not a constant expression", t); | |
5307 | return false; | |
5308 | } | |
5309 | return true; | |
5310 | ||
09b42213 | 5311 | case AGGR_INIT_EXPR: |
5312 | case CALL_EXPR: | |
5313 | /* -- an invocation of a function other than a constexpr function | |
5314 | or a constexpr constructor. */ | |
5315 | { | |
5316 | tree fun = get_function_named_in_call (t); | |
5317 | const int nargs = call_expr_nargs (t); | |
5318 | i = 0; | |
5319 | ||
9c96033c | 5320 | if (fun == NULL_TREE) |
5321 | { | |
732905bb | 5322 | /* Reset to allow the function to continue past the end |
5323 | of the block below. Otherwise return early. */ | |
5324 | bool bail = true; | |
5325 | ||
32cf7025 | 5326 | if (TREE_CODE (t) == CALL_EXPR |
5327 | && CALL_EXPR_FN (t) == NULL_TREE) | |
5328 | switch (CALL_EXPR_IFN (t)) | |
5329 | { | |
5330 | /* These should be ignored, they are optimized away from | |
5331 | constexpr functions. */ | |
5332 | case IFN_UBSAN_NULL: | |
5333 | case IFN_UBSAN_BOUNDS: | |
5334 | case IFN_UBSAN_VPTR: | |
3c77f69c | 5335 | case IFN_FALLTHROUGH: |
32cf7025 | 5336 | return true; |
732905bb | 5337 | |
5338 | case IFN_ADD_OVERFLOW: | |
5339 | case IFN_SUB_OVERFLOW: | |
5340 | case IFN_MUL_OVERFLOW: | |
6e1b2ffb | 5341 | case IFN_LAUNDER: |
732905bb | 5342 | bail = false; |
5343 | ||
32cf7025 | 5344 | default: |
5345 | break; | |
5346 | } | |
732905bb | 5347 | |
5348 | if (bail) | |
5349 | { | |
5350 | /* fold_call_expr can't do anything with IFN calls. */ | |
5351 | if (flags & tf_error) | |
d6a08f5c | 5352 | error_at (loc, "call to internal function %qE", t); |
732905bb | 5353 | return false; |
5354 | } | |
9c96033c | 5355 | } |
732905bb | 5356 | |
5357 | if (fun && is_overloaded_fn (fun)) | |
09b42213 | 5358 | { |
5359 | if (TREE_CODE (fun) == FUNCTION_DECL) | |
5360 | { | |
5361 | if (builtin_valid_in_constant_expr_p (fun)) | |
5362 | return true; | |
5363 | if (!DECL_DECLARED_CONSTEXPR_P (fun) | |
5364 | /* Allow any built-in function; if the expansion | |
5365 | isn't constant, we'll deal with that then. */ | |
5366 | && !is_builtin_fn (fun)) | |
5367 | { | |
5368 | if (flags & tf_error) | |
5369 | { | |
5967b28b | 5370 | error_at (loc, "call to non-%<constexpr%> function %qD", |
d6a08f5c | 5371 | fun); |
09b42213 | 5372 | explain_invalid_constexpr_fn (fun); |
5373 | } | |
5374 | return false; | |
5375 | } | |
5376 | /* A call to a non-static member function takes the address | |
5377 | of the object as the first argument. But in a constant | |
5378 | expression the address will be folded away, so look | |
5379 | through it now. */ | |
5380 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
5381 | && !DECL_CONSTRUCTOR_P (fun)) | |
5382 | { | |
5383 | tree x = get_nth_callarg (t, 0); | |
5384 | if (is_this_parameter (x)) | |
cf72f34d | 5385 | return true; |
7e1f8be4 | 5386 | /* Don't require an immediately constant value, as |
5387 | constexpr substitution might not use the value. */ | |
5388 | bool sub_now = false; | |
5389 | if (!potential_constant_expression_1 (x, rval, strict, | |
5390 | sub_now, flags)) | |
09b42213 | 5391 | return false; |
5392 | i = 1; | |
5393 | } | |
5394 | } | |
5395 | else | |
5396 | { | |
2055d27a | 5397 | if (!RECUR (fun, true)) |
09b42213 | 5398 | return false; |
5399 | fun = get_first_fn (fun); | |
5400 | } | |
5401 | /* Skip initial arguments to base constructors. */ | |
5402 | if (DECL_BASE_CONSTRUCTOR_P (fun)) | |
5403 | i = num_artificial_parms_for (fun); | |
5404 | fun = DECL_ORIGIN (fun); | |
5405 | } | |
732905bb | 5406 | else if (fun) |
09b42213 | 5407 | { |
2055d27a | 5408 | if (RECUR (fun, rval)) |
09b42213 | 5409 | /* Might end up being a constant function pointer. */; |
5410 | else | |
5411 | return false; | |
5412 | } | |
5413 | for (; i < nargs; ++i) | |
5414 | { | |
5415 | tree x = get_nth_callarg (t, i); | |
b2742b58 | 5416 | /* In a template, reference arguments haven't been converted to |
5417 | REFERENCE_TYPE and we might not even know if the parameter | |
5418 | is a reference, so accept lvalue constants too. */ | |
5419 | bool rv = processing_template_decl ? any : rval; | |
7e1f8be4 | 5420 | /* Don't require an immediately constant value, as constexpr |
5421 | substitution might not use the value of the argument. */ | |
5422 | bool sub_now = false; | |
5423 | if (!potential_constant_expression_1 (x, rv, strict, | |
5424 | sub_now, flags)) | |
09b42213 | 5425 | return false; |
5426 | } | |
5427 | return true; | |
5428 | } | |
5429 | ||
5430 | case NON_LVALUE_EXPR: | |
5431 | /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to | |
5432 | -- an lvalue of integral type that refers to a non-volatile | |
5433 | const variable or static data member initialized with | |
5434 | constant expressions, or | |
5435 | ||
5436 | -- an lvalue of literal type that refers to non-volatile | |
5437 | object defined with constexpr, or that refers to a | |
5438 | sub-object of such an object; */ | |
2055d27a | 5439 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 5440 | |
5441 | case VAR_DECL: | |
9c8aeb66 | 5442 | if (DECL_HAS_VALUE_EXPR_P (t)) |
297de7bc | 5443 | { |
d0e2b7e7 | 5444 | if (now && is_normal_capture_proxy (t)) |
297de7bc | 5445 | { |
5446 | /* -- in a lambda-expression, a reference to this or to a | |
5447 | variable with automatic storage duration defined outside that | |
5448 | lambda-expression, where the reference would be an | |
5449 | odr-use. */ | |
5450 | if (flags & tf_error) | |
5451 | { | |
5452 | tree cap = DECL_CAPTURED_VARIABLE (t); | |
5453 | error ("lambda capture of %qE is not a constant expression", | |
5454 | cap); | |
5455 | if (!want_rval && decl_constant_var_p (cap)) | |
5456 | inform (input_location, "because it is used as a glvalue"); | |
5457 | } | |
5458 | return false; | |
5459 | } | |
5460 | return RECUR (DECL_VALUE_EXPR (t), rval); | |
5461 | } | |
2055d27a | 5462 | if (want_rval |
33603066 | 5463 | && !var_in_maybe_constexpr_fn (t) |
c7282bf2 | 5464 | && !type_dependent_expression_p (t) |
8d6486e1 | 5465 | && !decl_maybe_constant_var_p (t) |
2055d27a | 5466 | && (strict |
5467 | || !CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (t)) | |
8d6486e1 | 5468 | || (DECL_INITIAL (t) |
5469 | && !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (t))) | |
c7282bf2 | 5470 | && COMPLETE_TYPE_P (TREE_TYPE (t)) |
5471 | && !is_really_empty_class (TREE_TYPE (t))) | |
09b42213 | 5472 | { |
5473 | if (flags & tf_error) | |
5474 | non_const_var_error (t); | |
5475 | return false; | |
5476 | } | |
5477 | return true; | |
5478 | ||
5479 | case NOP_EXPR: | |
5480 | case CONVERT_EXPR: | |
5481 | case VIEW_CONVERT_EXPR: | |
5482 | /* -- a reinterpret_cast. FIXME not implemented, and this rule | |
5483 | may change to something more specific to type-punning (DR 1312). */ | |
5484 | { | |
5485 | tree from = TREE_OPERAND (t, 0); | |
5486 | if (POINTER_TYPE_P (TREE_TYPE (t)) | |
5487 | && TREE_CODE (from) == INTEGER_CST | |
5488 | && !integer_zerop (from)) | |
5489 | { | |
5490 | if (flags & tf_error) | |
d6a08f5c | 5491 | error_at (loc, "reinterpret_cast from integer to pointer"); |
09b42213 | 5492 | return false; |
5493 | } | |
2055d27a | 5494 | return (RECUR (from, TREE_CODE (t) != VIEW_CONVERT_EXPR)); |
09b42213 | 5495 | } |
5496 | ||
cd45162d | 5497 | case ADDRESSOF_EXPR: |
5498 | /* This is like ADDR_EXPR, except it won't form pointer-to-member. */ | |
5499 | t = TREE_OPERAND (t, 0); | |
5500 | goto handle_addr_expr; | |
5501 | ||
09b42213 | 5502 | case ADDR_EXPR: |
5503 | /* -- a unary operator & that is applied to an lvalue that | |
5504 | designates an object with thread or automatic storage | |
5505 | duration; */ | |
5506 | t = TREE_OPERAND (t, 0); | |
5507 | ||
5508 | if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t)) | |
5509 | /* A pointer-to-member constant. */ | |
5510 | return true; | |
5511 | ||
cd45162d | 5512 | handle_addr_expr: |
09b42213 | 5513 | #if 0 |
5514 | /* FIXME adjust when issue 1197 is fully resolved. For now don't do | |
5515 | any checking here, as we might dereference the pointer later. If | |
5516 | we remove this code, also remove check_automatic_or_tls. */ | |
5517 | i = check_automatic_or_tls (t); | |
5518 | if (i == ck_ok) | |
5519 | return true; | |
5520 | if (i == ck_bad) | |
5521 | { | |
5522 | if (flags & tf_error) | |
5523 | error ("address-of an object %qE with thread local or " | |
5524 | "automatic storage is not a constant expression", t); | |
5525 | return false; | |
5526 | } | |
5527 | #endif | |
2055d27a | 5528 | return RECUR (t, any); |
09b42213 | 5529 | |
20b34a56 | 5530 | case REALPART_EXPR: |
5531 | case IMAGPART_EXPR: | |
09b42213 | 5532 | case COMPONENT_REF: |
5533 | case BIT_FIELD_REF: | |
5534 | case ARROW_EXPR: | |
5535 | case OFFSET_REF: | |
5536 | /* -- a class member access unless its postfix-expression is | |
5537 | of literal type or of pointer to literal type. */ | |
5538 | /* This test would be redundant, as it follows from the | |
5539 | postfix-expression being a potential constant expression. */ | |
eade0940 | 5540 | if (type_unknown_p (t)) |
5541 | return true; | |
2055d27a | 5542 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5543 | |
5544 | case EXPR_PACK_EXPANSION: | |
2055d27a | 5545 | return RECUR (PACK_EXPANSION_PATTERN (t), want_rval); |
09b42213 | 5546 | |
5547 | case INDIRECT_REF: | |
5548 | { | |
5549 | tree x = TREE_OPERAND (t, 0); | |
5550 | STRIP_NOPS (x); | |
997bbf70 | 5551 | if (is_this_parameter (x) && !is_capture_proxy (x)) |
09b42213 | 5552 | { |
b7e4a558 | 5553 | if (!var_in_maybe_constexpr_fn (x)) |
09b42213 | 5554 | { |
5555 | if (flags & tf_error) | |
d6a08f5c | 5556 | error_at (loc, "use of %<this%> in a constant expression"); |
09b42213 | 5557 | return false; |
5558 | } | |
09b42213 | 5559 | return true; |
5560 | } | |
2055d27a | 5561 | return RECUR (x, rval); |
09b42213 | 5562 | } |
5563 | ||
9c96033c | 5564 | case STATEMENT_LIST: |
5565 | { | |
5566 | tree_stmt_iterator i; | |
5567 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
5568 | { | |
2055d27a | 5569 | if (!RECUR (tsi_stmt (i), any)) |
9c96033c | 5570 | return false; |
5571 | } | |
5572 | return true; | |
5573 | } | |
5574 | break; | |
5575 | ||
5576 | case MODIFY_EXPR: | |
5577 | if (cxx_dialect < cxx14) | |
5578 | goto fail; | |
2055d27a | 5579 | if (!RECUR (TREE_OPERAND (t, 0), any)) |
9c96033c | 5580 | return false; |
2055d27a | 5581 | if (!RECUR (TREE_OPERAND (t, 1), rval)) |
9c96033c | 5582 | return false; |
5583 | return true; | |
5584 | ||
5585 | case MODOP_EXPR: | |
5586 | if (cxx_dialect < cxx14) | |
5587 | goto fail; | |
2055d27a | 5588 | if (!RECUR (TREE_OPERAND (t, 0), rval)) |
9c96033c | 5589 | return false; |
2055d27a | 5590 | if (!RECUR (TREE_OPERAND (t, 2), rval)) |
9c96033c | 5591 | return false; |
5592 | return true; | |
5593 | ||
9c96033c | 5594 | case DO_STMT: |
2055d27a | 5595 | if (!RECUR (DO_COND (t), rval)) |
9c96033c | 5596 | return false; |
2055d27a | 5597 | if (!RECUR (DO_BODY (t), any)) |
9c96033c | 5598 | return false; |
5599 | return true; | |
5600 | ||
5601 | case FOR_STMT: | |
2055d27a | 5602 | if (!RECUR (FOR_INIT_STMT (t), any)) |
9c96033c | 5603 | return false; |
2055d27a | 5604 | if (!RECUR (FOR_COND (t), rval)) |
9c96033c | 5605 | return false; |
2055d27a | 5606 | if (!RECUR (FOR_EXPR (t), any)) |
9c96033c | 5607 | return false; |
2055d27a | 5608 | if (!RECUR (FOR_BODY (t), any)) |
9c96033c | 5609 | return false; |
5610 | return true; | |
5611 | ||
33603066 | 5612 | case RANGE_FOR_STMT: |
5613 | if (!RECUR (RANGE_FOR_EXPR (t), any)) | |
5614 | return false; | |
5615 | if (!RECUR (RANGE_FOR_BODY (t), any)) | |
5616 | return false; | |
5617 | return true; | |
5618 | ||
9c96033c | 5619 | case WHILE_STMT: |
2055d27a | 5620 | if (!RECUR (WHILE_COND (t), rval)) |
9c96033c | 5621 | return false; |
2055d27a | 5622 | if (!RECUR (WHILE_BODY (t), any)) |
9c96033c | 5623 | return false; |
5624 | return true; | |
5625 | ||
5626 | case SWITCH_STMT: | |
2055d27a | 5627 | if (!RECUR (SWITCH_STMT_COND (t), rval)) |
9c96033c | 5628 | return false; |
748c426a | 5629 | /* FIXME we don't check SWITCH_STMT_BODY currently, because even |
5630 | unreachable labels would be checked. */ | |
9c96033c | 5631 | return true; |
5632 | ||
da7981e0 | 5633 | case STMT_EXPR: |
2055d27a | 5634 | return RECUR (STMT_EXPR_STMT (t), rval); |
da7981e0 | 5635 | |
09b42213 | 5636 | case LAMBDA_EXPR: |
27db1f50 | 5637 | if (cxx_dialect >= cxx17) |
5638 | /* In C++17 lambdas can be constexpr, don't give up yet. */ | |
5639 | return true; | |
5640 | else if (flags & tf_error) | |
5641 | error_at (loc, "lambda-expression is not a constant expression " | |
5642 | "before C++17"); | |
5643 | return false; | |
5644 | ||
09b42213 | 5645 | case DYNAMIC_CAST_EXPR: |
5646 | case PSEUDO_DTOR_EXPR: | |
09b42213 | 5647 | case NEW_EXPR: |
5648 | case VEC_NEW_EXPR: | |
5649 | case DELETE_EXPR: | |
5650 | case VEC_DELETE_EXPR: | |
5651 | case THROW_EXPR: | |
d6a08f5c | 5652 | case OMP_PARALLEL: |
5653 | case OMP_TASK: | |
5654 | case OMP_FOR: | |
83728168 | 5655 | case OMP_SIMD: |
d6a08f5c | 5656 | case OMP_DISTRIBUTE: |
5657 | case OMP_TASKLOOP: | |
5658 | case OMP_TEAMS: | |
5659 | case OMP_TARGET_DATA: | |
5660 | case OMP_TARGET: | |
5661 | case OMP_SECTIONS: | |
5662 | case OMP_ORDERED: | |
5663 | case OMP_CRITICAL: | |
5664 | case OMP_SINGLE: | |
5665 | case OMP_SECTION: | |
5666 | case OMP_MASTER: | |
5667 | case OMP_TASKGROUP: | |
5668 | case OMP_TARGET_UPDATE: | |
5669 | case OMP_TARGET_ENTER_DATA: | |
5670 | case OMP_TARGET_EXIT_DATA: | |
09b42213 | 5671 | case OMP_ATOMIC: |
5672 | case OMP_ATOMIC_READ: | |
5673 | case OMP_ATOMIC_CAPTURE_OLD: | |
5674 | case OMP_ATOMIC_CAPTURE_NEW: | |
d6a08f5c | 5675 | case OACC_PARALLEL: |
5676 | case OACC_KERNELS: | |
5677 | case OACC_DATA: | |
5678 | case OACC_HOST_DATA: | |
5679 | case OACC_LOOP: | |
5680 | case OACC_CACHE: | |
5681 | case OACC_DECLARE: | |
5682 | case OACC_ENTER_DATA: | |
5683 | case OACC_EXIT_DATA: | |
5684 | case OACC_UPDATE: | |
09b42213 | 5685 | /* GCC internal stuff. */ |
5686 | case VA_ARG_EXPR: | |
5687 | case OBJ_TYPE_REF: | |
09b42213 | 5688 | case TRANSACTION_EXPR: |
9c96033c | 5689 | case ASM_EXPR: |
9abecca2 | 5690 | case AT_ENCODE_EXPR: |
9c96033c | 5691 | fail: |
09b42213 | 5692 | if (flags & tf_error) |
d6a08f5c | 5693 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 5694 | return false; |
5695 | ||
5696 | case TYPEID_EXPR: | |
5697 | /* -- a typeid expression whose operand is of polymorphic | |
5698 | class type; */ | |
5699 | { | |
5700 | tree e = TREE_OPERAND (t, 0); | |
5701 | if (!TYPE_P (e) && !type_dependent_expression_p (e) | |
5702 | && TYPE_POLYMORPHIC_P (TREE_TYPE (e))) | |
5703 | { | |
5704 | if (flags & tf_error) | |
d6a08f5c | 5705 | error_at (loc, "typeid-expression is not a constant expression " |
5706 | "because %qE is of polymorphic type", e); | |
09b42213 | 5707 | return false; |
5708 | } | |
5709 | return true; | |
5710 | } | |
5711 | ||
57e83b58 | 5712 | case POINTER_DIFF_EXPR: |
09b42213 | 5713 | case MINUS_EXPR: |
09b42213 | 5714 | want_rval = true; |
5715 | goto binary; | |
5716 | ||
5717 | case LT_EXPR: | |
5718 | case LE_EXPR: | |
5719 | case GT_EXPR: | |
5720 | case GE_EXPR: | |
5721 | case EQ_EXPR: | |
5722 | case NE_EXPR: | |
09b42213 | 5723 | want_rval = true; |
5724 | goto binary; | |
5725 | ||
9c96033c | 5726 | case PREINCREMENT_EXPR: |
5727 | case POSTINCREMENT_EXPR: | |
5728 | case PREDECREMENT_EXPR: | |
5729 | case POSTDECREMENT_EXPR: | |
5730 | if (cxx_dialect < cxx14) | |
5731 | goto fail; | |
5732 | goto unary; | |
5733 | ||
09b42213 | 5734 | case BIT_NOT_EXPR: |
5735 | /* A destructor. */ | |
5736 | if (TYPE_P (TREE_OPERAND (t, 0))) | |
5737 | return true; | |
e3533433 | 5738 | /* fall through. */ |
09b42213 | 5739 | |
09b42213 | 5740 | case CONJ_EXPR: |
5741 | case SAVE_EXPR: | |
5742 | case FIX_TRUNC_EXPR: | |
5743 | case FLOAT_EXPR: | |
5744 | case NEGATE_EXPR: | |
5745 | case ABS_EXPR: | |
5746 | case TRUTH_NOT_EXPR: | |
5747 | case FIXED_CONVERT_EXPR: | |
5748 | case UNARY_PLUS_EXPR: | |
6fdf70f5 | 5749 | case UNARY_LEFT_FOLD_EXPR: |
5750 | case UNARY_RIGHT_FOLD_EXPR: | |
9c96033c | 5751 | unary: |
2055d27a | 5752 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 5753 | |
5754 | case CAST_EXPR: | |
5755 | case CONST_CAST_EXPR: | |
5756 | case STATIC_CAST_EXPR: | |
5757 | case REINTERPRET_CAST_EXPR: | |
5758 | case IMPLICIT_CONV_EXPR: | |
5759 | if (cxx_dialect < cxx11 | |
5760 | && !dependent_type_p (TREE_TYPE (t)) | |
5761 | && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t))) | |
5762 | /* In C++98, a conversion to non-integral type can't be part of a | |
5763 | constant expression. */ | |
5764 | { | |
5765 | if (flags & tf_error) | |
d6a08f5c | 5766 | error_at (loc, |
5767 | "cast to non-integral type %qT in a constant expression", | |
5768 | TREE_TYPE (t)); | |
09b42213 | 5769 | return false; |
5770 | } | |
5771 | ||
2055d27a | 5772 | return (RECUR (TREE_OPERAND (t, 0), |
5773 | TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE)); | |
09b42213 | 5774 | |
9c96033c | 5775 | case BIND_EXPR: |
2055d27a | 5776 | return RECUR (BIND_EXPR_BODY (t), want_rval); |
9c96033c | 5777 | |
9c96033c | 5778 | case CLEANUP_POINT_EXPR: |
5779 | case MUST_NOT_THROW_EXPR: | |
5780 | case TRY_CATCH_EXPR: | |
7f67d68c | 5781 | case TRY_BLOCK: |
9c96033c | 5782 | case EH_SPEC_BLOCK: |
5783 | case EXPR_STMT: | |
09b42213 | 5784 | case PAREN_EXPR: |
5785 | case NON_DEPENDENT_EXPR: | |
5786 | /* For convenience. */ | |
5787 | case RETURN_EXPR: | |
d1980671 | 5788 | case LOOP_EXPR: |
5789 | case EXIT_EXPR: | |
2055d27a | 5790 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5791 | |
33603066 | 5792 | case DECL_EXPR: |
5793 | tmp = DECL_EXPR_DECL (t); | |
5794 | if (VAR_P (tmp) && !DECL_ARTIFICIAL (tmp)) | |
5795 | { | |
5796 | if (TREE_STATIC (tmp)) | |
5797 | { | |
5798 | if (flags & tf_error) | |
5799 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 5800 | "%<static%> in %<constexpr%> context", tmp); |
33603066 | 5801 | return false; |
5802 | } | |
5803 | else if (CP_DECL_THREAD_LOCAL_P (tmp)) | |
5804 | { | |
5805 | if (flags & tf_error) | |
5806 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 5807 | "%<thread_local%> in %<constexpr%> context", tmp); |
33603066 | 5808 | return false; |
5809 | } | |
282ea908 | 5810 | else if (!check_for_uninitialized_const_var |
5811 | (tmp, /*constexpr_context_p=*/true, flags)) | |
5812 | return false; | |
33603066 | 5813 | } |
5814 | return RECUR (tmp, want_rval); | |
5815 | ||
7f67d68c | 5816 | case TRY_FINALLY_EXPR: |
5817 | return (RECUR (TREE_OPERAND (t, 0), want_rval) | |
5818 | && RECUR (TREE_OPERAND (t, 1), any)); | |
5819 | ||
09b42213 | 5820 | case SCOPE_REF: |
2055d27a | 5821 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 5822 | |
5823 | case TARGET_EXPR: | |
07d8961c | 5824 | if (!TARGET_EXPR_DIRECT_INIT_P (t) |
5825 | && !literal_type_p (TREE_TYPE (t))) | |
09b42213 | 5826 | { |
5827 | if (flags & tf_error) | |
5828 | { | |
d6a08f5c | 5829 | error_at (loc, "temporary of non-literal type %qT in a " |
5830 | "constant expression", TREE_TYPE (t)); | |
09b42213 | 5831 | explain_non_literal_class (TREE_TYPE (t)); |
5832 | } | |
5833 | return false; | |
5834 | } | |
e3533433 | 5835 | /* FALLTHRU */ |
09b42213 | 5836 | case INIT_EXPR: |
2055d27a | 5837 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 5838 | |
5839 | case CONSTRUCTOR: | |
5840 | { | |
5841 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
5842 | constructor_elt *ce; | |
5843 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2055d27a | 5844 | if (!RECUR (ce->value, want_rval)) |
09b42213 | 5845 | return false; |
5846 | return true; | |
5847 | } | |
5848 | ||
5849 | case TREE_LIST: | |
5850 | { | |
5851 | gcc_assert (TREE_PURPOSE (t) == NULL_TREE | |
5852 | || DECL_P (TREE_PURPOSE (t))); | |
2055d27a | 5853 | if (!RECUR (TREE_VALUE (t), want_rval)) |
09b42213 | 5854 | return false; |
5855 | if (TREE_CHAIN (t) == NULL_TREE) | |
5856 | return true; | |
2055d27a | 5857 | return RECUR (TREE_CHAIN (t), want_rval); |
09b42213 | 5858 | } |
5859 | ||
5860 | case TRUNC_DIV_EXPR: | |
5861 | case CEIL_DIV_EXPR: | |
5862 | case FLOOR_DIV_EXPR: | |
5863 | case ROUND_DIV_EXPR: | |
5864 | case TRUNC_MOD_EXPR: | |
5865 | case CEIL_MOD_EXPR: | |
5866 | case ROUND_MOD_EXPR: | |
5867 | { | |
5868 | tree denom = TREE_OPERAND (t, 1); | |
2055d27a | 5869 | if (!RECUR (denom, rval)) |
09b42213 | 5870 | return false; |
5871 | /* We can't call cxx_eval_outermost_constant_expr on an expression | |
21131a05 | 5872 | that hasn't been through instantiate_non_dependent_expr yet. */ |
09b42213 | 5873 | if (!processing_template_decl) |
5874 | denom = cxx_eval_outermost_constant_expr (denom, true); | |
5875 | if (integer_zerop (denom)) | |
5876 | { | |
5877 | if (flags & tf_error) | |
ea034e2c | 5878 | error ("division by zero is not a constant expression"); |
09b42213 | 5879 | return false; |
5880 | } | |
5881 | else | |
5882 | { | |
5883 | want_rval = true; | |
2055d27a | 5884 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5885 | } |
5886 | } | |
5887 | ||
5888 | case COMPOUND_EXPR: | |
5889 | { | |
5890 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
5891 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
5892 | introduced by build_call_a. */ | |
5893 | tree op0 = TREE_OPERAND (t, 0); | |
5894 | tree op1 = TREE_OPERAND (t, 1); | |
5895 | STRIP_NOPS (op1); | |
5896 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
5897 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
2055d27a | 5898 | return RECUR (op0, want_rval); |
09b42213 | 5899 | else |
5900 | goto binary; | |
5901 | } | |
5902 | ||
5903 | /* If the first operand is the non-short-circuit constant, look at | |
5904 | the second operand; otherwise we only care about the first one for | |
5905 | potentiality. */ | |
5906 | case TRUTH_AND_EXPR: | |
5907 | case TRUTH_ANDIF_EXPR: | |
5908 | tmp = boolean_true_node; | |
5909 | goto truth; | |
5910 | case TRUTH_OR_EXPR: | |
5911 | case TRUTH_ORIF_EXPR: | |
5912 | tmp = boolean_false_node; | |
5913 | truth: | |
5914 | { | |
5915 | tree op = TREE_OPERAND (t, 0); | |
2055d27a | 5916 | if (!RECUR (op, rval)) |
09b42213 | 5917 | return false; |
5918 | if (!processing_template_decl) | |
5919 | op = cxx_eval_outermost_constant_expr (op, true); | |
5920 | if (tree_int_cst_equal (op, tmp)) | |
2055d27a | 5921 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 5922 | else |
5923 | return true; | |
5924 | } | |
5925 | ||
5926 | case PLUS_EXPR: | |
5927 | case MULT_EXPR: | |
5928 | case POINTER_PLUS_EXPR: | |
5929 | case RDIV_EXPR: | |
5930 | case EXACT_DIV_EXPR: | |
5931 | case MIN_EXPR: | |
5932 | case MAX_EXPR: | |
5933 | case LSHIFT_EXPR: | |
5934 | case RSHIFT_EXPR: | |
5935 | case LROTATE_EXPR: | |
5936 | case RROTATE_EXPR: | |
5937 | case BIT_IOR_EXPR: | |
5938 | case BIT_XOR_EXPR: | |
5939 | case BIT_AND_EXPR: | |
5940 | case TRUTH_XOR_EXPR: | |
5941 | case UNORDERED_EXPR: | |
5942 | case ORDERED_EXPR: | |
5943 | case UNLT_EXPR: | |
5944 | case UNLE_EXPR: | |
5945 | case UNGT_EXPR: | |
5946 | case UNGE_EXPR: | |
5947 | case UNEQ_EXPR: | |
5948 | case LTGT_EXPR: | |
5949 | case RANGE_EXPR: | |
5950 | case COMPLEX_EXPR: | |
5951 | want_rval = true; | |
5952 | /* Fall through. */ | |
5953 | case ARRAY_REF: | |
5954 | case ARRAY_RANGE_REF: | |
5955 | case MEMBER_REF: | |
5956 | case DOTSTAR_EXPR: | |
f0abe78f | 5957 | case MEM_REF: |
6fdf70f5 | 5958 | case BINARY_LEFT_FOLD_EXPR: |
5959 | case BINARY_RIGHT_FOLD_EXPR: | |
09b42213 | 5960 | binary: |
5961 | for (i = 0; i < 2; ++i) | |
2055d27a | 5962 | if (!RECUR (TREE_OPERAND (t, i), want_rval)) |
09b42213 | 5963 | return false; |
5964 | return true; | |
5965 | ||
09b42213 | 5966 | case FMA_EXPR: |
5967 | case VEC_PERM_EXPR: | |
5968 | for (i = 0; i < 3; ++i) | |
2055d27a | 5969 | if (!RECUR (TREE_OPERAND (t, i), true)) |
09b42213 | 5970 | return false; |
5971 | return true; | |
5972 | ||
5973 | case COND_EXPR: | |
b0fe8b95 | 5974 | if (COND_EXPR_IS_VEC_DELETE (t)) |
5975 | { | |
5976 | if (flags & tf_error) | |
d6a08f5c | 5977 | error_at (loc, "%<delete[]%> is not a constant expression"); |
b0fe8b95 | 5978 | return false; |
5979 | } | |
5980 | /* Fall through. */ | |
5981 | case IF_STMT: | |
09b42213 | 5982 | case VEC_COND_EXPR: |
5983 | /* If the condition is a known constant, we know which of the legs we | |
5984 | care about; otherwise we only require that the condition and | |
5985 | either of the legs be potentially constant. */ | |
5986 | tmp = TREE_OPERAND (t, 0); | |
2055d27a | 5987 | if (!RECUR (tmp, rval)) |
09b42213 | 5988 | return false; |
5989 | if (!processing_template_decl) | |
5990 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
5991 | if (integer_zerop (tmp)) | |
2055d27a | 5992 | return RECUR (TREE_OPERAND (t, 2), want_rval); |
09b42213 | 5993 | else if (TREE_CODE (tmp) == INTEGER_CST) |
2055d27a | 5994 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 5995 | for (i = 1; i < 3; ++i) |
5996 | if (potential_constant_expression_1 (TREE_OPERAND (t, i), | |
7e1f8be4 | 5997 | want_rval, strict, now, tf_none)) |
09b42213 | 5998 | return true; |
5999 | if (flags & tf_error) | |
d6a08f5c | 6000 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 6001 | return false; |
6002 | ||
6003 | case VEC_INIT_EXPR: | |
6004 | if (VEC_INIT_EXPR_IS_CONSTEXPR (t)) | |
6005 | return true; | |
6006 | if (flags & tf_error) | |
6007 | { | |
d6a08f5c | 6008 | error_at (loc, "non-constant array initialization"); |
09b42213 | 6009 | diagnose_non_constexpr_vec_init (t); |
6010 | } | |
6011 | return false; | |
6012 | ||
db1ae94f | 6013 | case TYPE_DECL: |
6014 | case TAG_DEFN: | |
6015 | /* We can see these in statement-expressions. */ | |
6016 | return true; | |
6017 | ||
fd130325 | 6018 | case CLEANUP_STMT: |
d2c63826 | 6019 | case EMPTY_CLASS_EXPR: |
38ef3642 | 6020 | case PREDICT_EXPR: |
d2c63826 | 6021 | return false; |
6022 | ||
d1980671 | 6023 | case GOTO_EXPR: |
6024 | { | |
6025 | tree *target = &TREE_OPERAND (t, 0); | |
d40a1eac | 6026 | /* Gotos representing break and continue are OK. */ |
6027 | if (breaks (target) || continues (target)) | |
6028 | return true; | |
6029 | if (flags & tf_error) | |
d6a08f5c | 6030 | error_at (loc, "%<goto%> is not a constant expression"); |
d40a1eac | 6031 | return false; |
d1980671 | 6032 | } |
6033 | ||
24c6ee98 | 6034 | case ANNOTATE_EXPR: |
24c6ee98 | 6035 | return RECUR (TREE_OPERAND (t, 0), rval); |
6036 | ||
09b42213 | 6037 | default: |
6038 | if (objc_is_property_ref (t)) | |
6039 | return false; | |
6040 | ||
6041 | sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t))); | |
d40a1eac | 6042 | gcc_unreachable (); |
09b42213 | 6043 | return false; |
6044 | } | |
2055d27a | 6045 | #undef RECUR |
09b42213 | 6046 | } |
6047 | ||
6048 | /* The main entry point to the above. */ | |
6049 | ||
6050 | bool | |
6051 | potential_constant_expression (tree t) | |
6052 | { | |
7e1f8be4 | 6053 | return potential_constant_expression_1 (t, false, true, false, tf_none); |
09b42213 | 6054 | } |
6055 | ||
6056 | /* As above, but require a constant rvalue. */ | |
6057 | ||
6058 | bool | |
6059 | potential_rvalue_constant_expression (tree t) | |
6060 | { | |
7e1f8be4 | 6061 | return potential_constant_expression_1 (t, true, true, false, tf_none); |
09b42213 | 6062 | } |
6063 | ||
6064 | /* Like above, but complain about non-constant expressions. */ | |
6065 | ||
6066 | bool | |
6067 | require_potential_constant_expression (tree t) | |
6068 | { | |
786721dc | 6069 | return potential_constant_expression_1 (t, false, true, false, |
6070 | tf_warning_or_error); | |
09b42213 | 6071 | } |
6072 | ||
6073 | /* Cross product of the above. */ | |
6074 | ||
6075 | bool | |
6076 | require_potential_rvalue_constant_expression (tree t) | |
6077 | { | |
786721dc | 6078 | return potential_constant_expression_1 (t, true, true, false, |
6079 | tf_warning_or_error); | |
6080 | } | |
6081 | ||
6082 | /* Like above, but don't consider PARM_DECL a potential_constant_expression. */ | |
6083 | ||
6084 | bool | |
6085 | require_rvalue_constant_expression (tree t) | |
6086 | { | |
6087 | return potential_constant_expression_1 (t, true, true, true, | |
6088 | tf_warning_or_error); | |
7e1f8be4 | 6089 | } |
6090 | ||
6091 | /* Like potential_constant_expression, but don't consider possible constexpr | |
6092 | substitution of the current function. That is, PARM_DECL qualifies under | |
6093 | potential_constant_expression, but not here. | |
6094 | ||
6095 | This is basically what you can check when any actual constant values might | |
6096 | be value-dependent. */ | |
6097 | ||
6098 | bool | |
6099 | is_constant_expression (tree t) | |
6100 | { | |
6101 | return potential_constant_expression_1 (t, false, true, true, tf_none); | |
6102 | } | |
6103 | ||
6104 | /* Like above, but complain about non-constant expressions. */ | |
6105 | ||
6106 | bool | |
6107 | require_constant_expression (tree t) | |
6108 | { | |
6109 | return potential_constant_expression_1 (t, false, true, true, | |
6110 | tf_warning_or_error); | |
6111 | } | |
6112 | ||
6113 | /* Like is_constant_expression, but allow const variables that are not allowed | |
6114 | under constexpr rules. */ | |
6115 | ||
6116 | bool | |
6117 | is_static_init_expression (tree t) | |
6118 | { | |
6119 | return potential_constant_expression_1 (t, false, false, true, tf_none); | |
09b42213 | 6120 | } |
6121 | ||
29cf24ec | 6122 | /* Returns true if T is a potential constant expression that is not |
6123 | instantiation-dependent, and therefore a candidate for constant folding even | |
6124 | in a template. */ | |
6125 | ||
6126 | bool | |
7e1f8be4 | 6127 | is_nondependent_constant_expression (tree t) |
29cf24ec | 6128 | { |
6129 | return (!type_unknown_p (t) | |
6130 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6131 | && is_constant_expression (t) |
29cf24ec | 6132 | && !instantiation_dependent_expression_p (t)); |
6133 | } | |
6134 | ||
6135 | /* Returns true if T is a potential static initializer expression that is not | |
6136 | instantiation-dependent. */ | |
6137 | ||
6138 | bool | |
7e1f8be4 | 6139 | is_nondependent_static_init_expression (tree t) |
29cf24ec | 6140 | { |
6141 | return (!type_unknown_p (t) | |
6142 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6143 | && is_static_init_expression (t) |
29cf24ec | 6144 | && !instantiation_dependent_expression_p (t)); |
6145 | } | |
6146 | ||
a050099a | 6147 | /* Finalize constexpr processing after parsing. */ |
6148 | ||
6149 | void | |
6150 | fini_constexpr (void) | |
6151 | { | |
6152 | /* The contexpr call and fundef copies tables are no longer needed. */ | |
6153 | constexpr_call_table = NULL; | |
6154 | fundef_copies_table = NULL; | |
6155 | } | |
6156 | ||
09b42213 | 6157 | #include "gt-cp-constexpr.h" |