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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 | ||
9a97d94a | 44 | static HOST_WIDE_INT find_array_ctor_elt (tree ary, tree dindex, |
45 | bool insert = false); | |
46 | ||
09b42213 | 47 | /* Returns true iff FUN is an instantiation of a constexpr function |
48 | template or a defaulted constexpr function. */ | |
49 | ||
50 | bool | |
51 | is_instantiation_of_constexpr (tree fun) | |
52 | { | |
53 | return ((DECL_TEMPLOID_INSTANTIATION (fun) | |
54 | && DECL_DECLARED_CONSTEXPR_P (DECL_TI_TEMPLATE (fun))) | |
55 | || (DECL_DEFAULTED_FN (fun) | |
56 | && DECL_DECLARED_CONSTEXPR_P (fun))); | |
57 | } | |
58 | ||
59 | /* Return true if T is a literal type. */ | |
60 | ||
61 | bool | |
62 | literal_type_p (tree t) | |
63 | { | |
64 | if (SCALAR_TYPE_P (t) | |
76249021 | 65 | || VECTOR_TYPE_P (t) |
90ad495b | 66 | || TYPE_REF_P (t) |
dd418b39 | 67 | || (VOID_TYPE_P (t) && cxx_dialect >= cxx14)) |
09b42213 | 68 | return true; |
69 | if (CLASS_TYPE_P (t)) | |
70 | { | |
71 | t = complete_type (t); | |
72 | gcc_assert (COMPLETE_TYPE_P (t) || errorcount); | |
73 | return CLASSTYPE_LITERAL_P (t); | |
74 | } | |
75 | if (TREE_CODE (t) == ARRAY_TYPE) | |
76 | return literal_type_p (strip_array_types (t)); | |
77 | return false; | |
78 | } | |
79 | ||
80 | /* If DECL is a variable declared `constexpr', require its type | |
e89257db | 81 | be literal. Return error_mark_node if we give an error, the |
82 | DECL otherwise. */ | |
09b42213 | 83 | |
84 | tree | |
85 | ensure_literal_type_for_constexpr_object (tree decl) | |
86 | { | |
87 | tree type = TREE_TYPE (decl); | |
88 | if (VAR_P (decl) | |
89 | && (DECL_DECLARED_CONSTEXPR_P (decl) | |
90 | || var_in_constexpr_fn (decl)) | |
91 | && !processing_template_decl) | |
92 | { | |
93 | tree stype = strip_array_types (type); | |
94 | if (CLASS_TYPE_P (stype) && !COMPLETE_TYPE_P (complete_type (stype))) | |
95 | /* Don't complain here, we'll complain about incompleteness | |
96 | when we try to initialize the variable. */; | |
03dbe51b | 97 | else if (type_uses_auto (type)) |
98 | /* We don't know the actual type yet. */; | |
09b42213 | 99 | else if (!literal_type_p (type)) |
100 | { | |
101 | if (DECL_DECLARED_CONSTEXPR_P (decl)) | |
e45408ff | 102 | { |
bc35ef65 | 103 | auto_diagnostic_group d; |
04e6d9db | 104 | error_at (DECL_SOURCE_LOCATION (decl), |
105 | "the type %qT of %<constexpr%> variable %qD " | |
106 | "is not literal", type, decl); | |
e45408ff | 107 | explain_non_literal_class (type); |
e89257db | 108 | decl = error_mark_node; |
e45408ff | 109 | } |
09b42213 | 110 | else |
9c96033c | 111 | { |
b7e4a558 | 112 | if (!is_instantiation_of_constexpr (current_function_decl)) |
e45408ff | 113 | { |
bc35ef65 | 114 | auto_diagnostic_group d; |
04e6d9db | 115 | error_at (DECL_SOURCE_LOCATION (decl), |
116 | "variable %qD of non-literal type %qT in " | |
117 | "%<constexpr%> function", decl, type); | |
e45408ff | 118 | explain_non_literal_class (type); |
e89257db | 119 | decl = error_mark_node; |
e45408ff | 120 | } |
9c96033c | 121 | cp_function_chain->invalid_constexpr = true; |
122 | } | |
09b42213 | 123 | } |
fdafeeb7 | 124 | else if (DECL_DECLARED_CONSTEXPR_P (decl) |
125 | && variably_modified_type_p (type, NULL_TREE)) | |
126 | { | |
04e6d9db | 127 | error_at (DECL_SOURCE_LOCATION (decl), |
128 | "%<constexpr%> variable %qD has variably-modified " | |
129 | "type %qT", decl, type); | |
fdafeeb7 | 130 | decl = error_mark_node; |
131 | } | |
09b42213 | 132 | } |
133 | return decl; | |
134 | } | |
135 | ||
136 | /* Representation of entries in the constexpr function definition table. */ | |
137 | ||
138 | struct GTY((for_user)) constexpr_fundef { | |
139 | tree decl; | |
140 | tree body; | |
141 | }; | |
142 | ||
b594087e | 143 | struct constexpr_fundef_hasher : ggc_ptr_hash<constexpr_fundef> |
09b42213 | 144 | { |
145 | static hashval_t hash (constexpr_fundef *); | |
146 | static bool equal (constexpr_fundef *, constexpr_fundef *); | |
147 | }; | |
148 | ||
149 | /* This table holds all constexpr function definitions seen in | |
150 | the current translation unit. */ | |
151 | ||
152 | static GTY (()) hash_table<constexpr_fundef_hasher> *constexpr_fundef_table; | |
153 | ||
154 | /* Utility function used for managing the constexpr function table. | |
155 | Return true if the entries pointed to by P and Q are for the | |
156 | same constexpr function. */ | |
157 | ||
158 | inline bool | |
159 | constexpr_fundef_hasher::equal (constexpr_fundef *lhs, constexpr_fundef *rhs) | |
160 | { | |
161 | return lhs->decl == rhs->decl; | |
162 | } | |
163 | ||
164 | /* Utility function used for managing the constexpr function table. | |
165 | Return a hash value for the entry pointed to by Q. */ | |
166 | ||
167 | inline hashval_t | |
168 | constexpr_fundef_hasher::hash (constexpr_fundef *fundef) | |
169 | { | |
170 | return DECL_UID (fundef->decl); | |
171 | } | |
172 | ||
173 | /* Return a previously saved definition of function FUN. */ | |
174 | ||
175 | static constexpr_fundef * | |
176 | retrieve_constexpr_fundef (tree fun) | |
177 | { | |
178 | constexpr_fundef fundef = { NULL, NULL }; | |
179 | if (constexpr_fundef_table == NULL) | |
180 | return NULL; | |
181 | ||
182 | fundef.decl = fun; | |
183 | return constexpr_fundef_table->find (&fundef); | |
184 | } | |
185 | ||
186 | /* Check whether the parameter and return types of FUN are valid for a | |
187 | constexpr function, and complain if COMPLAIN. */ | |
188 | ||
33603066 | 189 | bool |
09b42213 | 190 | is_valid_constexpr_fn (tree fun, bool complain) |
191 | { | |
192 | bool ret = true; | |
193 | ||
7896267d | 194 | if (DECL_INHERITED_CTOR (fun) |
09b42213 | 195 | && TREE_CODE (fun) == TEMPLATE_DECL) |
196 | { | |
197 | ret = false; | |
198 | if (complain) | |
5967b28b | 199 | error ("inherited constructor %qD is not %<constexpr%>", |
7896267d | 200 | DECL_INHERITED_CTOR (fun)); |
09b42213 | 201 | } |
202 | else | |
203 | { | |
204 | for (tree parm = FUNCTION_FIRST_USER_PARM (fun); | |
205 | parm != NULL_TREE; parm = TREE_CHAIN (parm)) | |
206 | if (!literal_type_p (TREE_TYPE (parm))) | |
207 | { | |
208 | ret = false; | |
209 | if (complain) | |
210 | { | |
bc35ef65 | 211 | auto_diagnostic_group d; |
5967b28b | 212 | error ("invalid type for parameter %d of %<constexpr%> " |
09b42213 | 213 | "function %q+#D", DECL_PARM_INDEX (parm), fun); |
214 | explain_non_literal_class (TREE_TYPE (parm)); | |
215 | } | |
216 | } | |
217 | } | |
218 | ||
672871ce | 219 | if (LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) && cxx_dialect < cxx17) |
220 | { | |
221 | ret = false; | |
222 | if (complain) | |
223 | inform (DECL_SOURCE_LOCATION (fun), | |
5967b28b | 224 | "lambdas are implicitly %<constexpr%> only in C++17 and later"); |
672871ce | 225 | } |
226 | else if (!DECL_CONSTRUCTOR_P (fun)) | |
09b42213 | 227 | { |
228 | tree rettype = TREE_TYPE (TREE_TYPE (fun)); | |
229 | if (!literal_type_p (rettype)) | |
230 | { | |
231 | ret = false; | |
232 | if (complain) | |
233 | { | |
bc35ef65 | 234 | auto_diagnostic_group d; |
5967b28b | 235 | error ("invalid return type %qT of %<constexpr%> function %q+D", |
09b42213 | 236 | rettype, fun); |
237 | explain_non_literal_class (rettype); | |
238 | } | |
239 | } | |
240 | ||
d66f34cf | 241 | /* C++14 DR 1684 removed this restriction. */ |
242 | if (cxx_dialect < cxx14 | |
243 | && DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
09b42213 | 244 | && !CLASSTYPE_LITERAL_P (DECL_CONTEXT (fun))) |
245 | { | |
246 | ret = false; | |
bc35ef65 | 247 | if (complain) |
248 | { | |
249 | auto_diagnostic_group d; | |
250 | if (pedwarn (DECL_SOURCE_LOCATION (fun), OPT_Wpedantic, | |
251 | "enclosing class of %<constexpr%> non-static" | |
252 | " member function %q+#D is not a literal type", | |
253 | fun)) | |
254 | explain_non_literal_class (DECL_CONTEXT (fun)); | |
255 | } | |
09b42213 | 256 | } |
257 | } | |
258 | else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun))) | |
259 | { | |
260 | ret = false; | |
261 | if (complain) | |
262 | error ("%q#T has virtual base classes", DECL_CONTEXT (fun)); | |
263 | } | |
264 | ||
265 | return ret; | |
266 | } | |
267 | ||
268 | /* Subroutine of build_data_member_initialization. MEMBER is a COMPONENT_REF | |
269 | for a member of an anonymous aggregate, INIT is the initializer for that | |
270 | member, and VEC_OUTER is the vector of constructor elements for the class | |
271 | whose constructor we are processing. Add the initializer to the vector | |
272 | and return true to indicate success. */ | |
273 | ||
274 | static bool | |
275 | build_anon_member_initialization (tree member, tree init, | |
276 | vec<constructor_elt, va_gc> **vec_outer) | |
277 | { | |
278 | /* MEMBER presents the relevant fields from the inside out, but we need | |
279 | to build up the initializer from the outside in so that we can reuse | |
280 | previously built CONSTRUCTORs if this is, say, the second field in an | |
281 | anonymous struct. So we use a vec as a stack. */ | |
282 | auto_vec<tree, 2> fields; | |
283 | do | |
284 | { | |
285 | fields.safe_push (TREE_OPERAND (member, 1)); | |
286 | member = TREE_OPERAND (member, 0); | |
287 | } | |
288 | while (ANON_AGGR_TYPE_P (TREE_TYPE (member)) | |
289 | && TREE_CODE (member) == COMPONENT_REF); | |
290 | ||
291 | /* VEC has the constructor elements vector for the context of FIELD. | |
292 | If FIELD is an anonymous aggregate, we will push inside it. */ | |
293 | vec<constructor_elt, va_gc> **vec = vec_outer; | |
294 | tree field; | |
295 | while (field = fields.pop(), | |
296 | ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
297 | { | |
298 | tree ctor; | |
299 | /* If there is already an outer constructor entry for the anonymous | |
300 | aggregate FIELD, use it; otherwise, insert one. */ | |
301 | if (vec_safe_is_empty (*vec) | |
302 | || (*vec)->last().index != field) | |
303 | { | |
304 | ctor = build_constructor (TREE_TYPE (field), NULL); | |
305 | CONSTRUCTOR_APPEND_ELT (*vec, field, ctor); | |
306 | } | |
307 | else | |
308 | ctor = (*vec)->last().value; | |
309 | vec = &CONSTRUCTOR_ELTS (ctor); | |
310 | } | |
311 | ||
312 | /* Now we're at the innermost field, the one that isn't an anonymous | |
313 | aggregate. Add its initializer to the CONSTRUCTOR and we're done. */ | |
314 | gcc_assert (fields.is_empty()); | |
315 | CONSTRUCTOR_APPEND_ELT (*vec, field, init); | |
316 | ||
317 | return true; | |
318 | } | |
319 | ||
320 | /* Subroutine of build_constexpr_constructor_member_initializers. | |
321 | The expression tree T represents a data member initialization | |
322 | in a (constexpr) constructor definition. Build a pairing of | |
323 | the data member with its initializer, and prepend that pair | |
324 | to the existing initialization pair INITS. */ | |
325 | ||
326 | static bool | |
327 | build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec) | |
328 | { | |
329 | tree member, init; | |
330 | if (TREE_CODE (t) == CLEANUP_POINT_EXPR) | |
331 | t = TREE_OPERAND (t, 0); | |
332 | if (TREE_CODE (t) == EXPR_STMT) | |
333 | t = TREE_OPERAND (t, 0); | |
334 | if (t == error_mark_node) | |
335 | return false; | |
336 | if (TREE_CODE (t) == STATEMENT_LIST) | |
337 | { | |
338 | tree_stmt_iterator i; | |
339 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
340 | { | |
341 | if (! build_data_member_initialization (tsi_stmt (i), vec)) | |
342 | return false; | |
343 | } | |
344 | return true; | |
345 | } | |
346 | if (TREE_CODE (t) == CLEANUP_STMT) | |
347 | { | |
348 | /* We can't see a CLEANUP_STMT in a constructor for a literal class, | |
349 | but we can in a constexpr constructor for a non-literal class. Just | |
350 | ignore it; either all the initialization will be constant, in which | |
351 | case the cleanup can't run, or it can't be constexpr. | |
352 | Still recurse into CLEANUP_BODY. */ | |
353 | return build_data_member_initialization (CLEANUP_BODY (t), vec); | |
354 | } | |
355 | if (TREE_CODE (t) == CONVERT_EXPR) | |
356 | t = TREE_OPERAND (t, 0); | |
357 | if (TREE_CODE (t) == INIT_EXPR | |
9c96033c | 358 | /* vptr initialization shows up as a MODIFY_EXPR. In C++14 we only |
359 | use what this function builds for cx_check_missing_mem_inits, and | |
360 | assignment in the ctor body doesn't count. */ | |
361 | || (cxx_dialect < cxx14 && TREE_CODE (t) == MODIFY_EXPR)) | |
09b42213 | 362 | { |
363 | member = TREE_OPERAND (t, 0); | |
364 | init = break_out_target_exprs (TREE_OPERAND (t, 1)); | |
365 | } | |
366 | else if (TREE_CODE (t) == CALL_EXPR) | |
367 | { | |
9c96033c | 368 | tree fn = get_callee_fndecl (t); |
369 | if (!fn || !DECL_CONSTRUCTOR_P (fn)) | |
370 | /* We're only interested in calls to subobject constructors. */ | |
371 | return true; | |
09b42213 | 372 | member = CALL_EXPR_ARG (t, 0); |
373 | /* We don't use build_cplus_new here because it complains about | |
374 | abstract bases. Leaving the call unwrapped means that it has the | |
375 | wrong type, but cxx_eval_constant_expression doesn't care. */ | |
376 | init = break_out_target_exprs (t); | |
377 | } | |
378 | else if (TREE_CODE (t) == BIND_EXPR) | |
379 | return build_data_member_initialization (BIND_EXPR_BODY (t), vec); | |
09b42213 | 380 | else |
9c96033c | 381 | /* Don't add anything else to the CONSTRUCTOR. */ |
382 | return true; | |
09b42213 | 383 | if (INDIRECT_REF_P (member)) |
384 | member = TREE_OPERAND (member, 0); | |
385 | if (TREE_CODE (member) == NOP_EXPR) | |
386 | { | |
387 | tree op = member; | |
388 | STRIP_NOPS (op); | |
389 | if (TREE_CODE (op) == ADDR_EXPR) | |
390 | { | |
391 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
392 | (TREE_TYPE (TREE_TYPE (op)), | |
393 | TREE_TYPE (TREE_TYPE (member)))); | |
394 | /* Initializing a cv-qualified member; we need to look through | |
395 | the const_cast. */ | |
396 | member = op; | |
397 | } | |
398 | else if (op == current_class_ptr | |
399 | && (same_type_ignoring_top_level_qualifiers_p | |
400 | (TREE_TYPE (TREE_TYPE (member)), | |
401 | current_class_type))) | |
402 | /* Delegating constructor. */ | |
403 | member = op; | |
404 | else | |
405 | { | |
406 | /* This is an initializer for an empty base; keep it for now so | |
407 | we can check it in cxx_eval_bare_aggregate. */ | |
408 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (member)))); | |
409 | } | |
410 | } | |
411 | if (TREE_CODE (member) == ADDR_EXPR) | |
412 | member = TREE_OPERAND (member, 0); | |
413 | if (TREE_CODE (member) == COMPONENT_REF) | |
414 | { | |
415 | tree aggr = TREE_OPERAND (member, 0); | |
4952bc85 | 416 | if (TREE_CODE (aggr) == VAR_DECL) |
417 | /* Initializing a local variable, don't add anything. */ | |
418 | return true; | |
09b42213 | 419 | if (TREE_CODE (aggr) != COMPONENT_REF) |
420 | /* Normal member initialization. */ | |
421 | member = TREE_OPERAND (member, 1); | |
422 | else if (ANON_AGGR_TYPE_P (TREE_TYPE (aggr))) | |
423 | /* Initializing a member of an anonymous union. */ | |
424 | return build_anon_member_initialization (member, init, vec); | |
425 | else | |
426 | /* We're initializing a vtable pointer in a base. Leave it as | |
427 | COMPONENT_REF so we remember the path to get to the vfield. */ | |
428 | gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node); | |
429 | } | |
430 | ||
c678e23e | 431 | /* Value-initialization can produce multiple initializers for the |
432 | same field; use the last one. */ | |
433 | if (!vec_safe_is_empty (*vec) && (*vec)->last().index == member) | |
434 | (*vec)->last().value = init; | |
435 | else | |
436 | CONSTRUCTOR_APPEND_ELT (*vec, member, init); | |
09b42213 | 437 | return true; |
438 | } | |
439 | ||
440 | /* Subroutine of check_constexpr_ctor_body_1 and constexpr_fn_retval. | |
441 | In C++11 mode checks that the TYPE_DECLs in the BIND_EXPR_VARS of a | |
442 | BIND_EXPR conform to 7.1.5/3/4 on typedef and alias declarations. */ | |
443 | ||
444 | static bool | |
445 | check_constexpr_bind_expr_vars (tree t) | |
446 | { | |
447 | gcc_assert (TREE_CODE (t) == BIND_EXPR); | |
448 | ||
09b42213 | 449 | for (tree var = BIND_EXPR_VARS (t); var; var = DECL_CHAIN (var)) |
450 | if (TREE_CODE (var) == TYPE_DECL | |
04103c39 | 451 | && DECL_IMPLICIT_TYPEDEF_P (var) |
452 | && !LAMBDA_TYPE_P (TREE_TYPE (var))) | |
09b42213 | 453 | return false; |
454 | return true; | |
455 | } | |
456 | ||
457 | /* Subroutine of check_constexpr_ctor_body. */ | |
458 | ||
459 | static bool | |
460 | check_constexpr_ctor_body_1 (tree last, tree list) | |
461 | { | |
462 | switch (TREE_CODE (list)) | |
463 | { | |
464 | case DECL_EXPR: | |
810702a2 | 465 | if (TREE_CODE (DECL_EXPR_DECL (list)) == USING_DECL |
466 | || TREE_CODE (DECL_EXPR_DECL (list)) == TYPE_DECL) | |
09b42213 | 467 | return true; |
09b42213 | 468 | return false; |
469 | ||
470 | case CLEANUP_POINT_EXPR: | |
471 | return check_constexpr_ctor_body (last, TREE_OPERAND (list, 0), | |
472 | /*complain=*/false); | |
473 | ||
474 | case BIND_EXPR: | |
475 | if (!check_constexpr_bind_expr_vars (list) | |
476 | || !check_constexpr_ctor_body (last, BIND_EXPR_BODY (list), | |
477 | /*complain=*/false)) | |
478 | return false; | |
479 | return true; | |
480 | ||
481 | case USING_STMT: | |
482 | case STATIC_ASSERT: | |
90567983 | 483 | case DEBUG_BEGIN_STMT: |
09b42213 | 484 | return true; |
485 | ||
486 | default: | |
487 | return false; | |
488 | } | |
489 | } | |
490 | ||
491 | /* Make sure that there are no statements after LAST in the constructor | |
492 | body represented by LIST. */ | |
493 | ||
494 | bool | |
495 | check_constexpr_ctor_body (tree last, tree list, bool complain) | |
496 | { | |
9c96033c | 497 | /* C++14 doesn't require a constexpr ctor to have an empty body. */ |
498 | if (cxx_dialect >= cxx14) | |
499 | return true; | |
500 | ||
09b42213 | 501 | bool ok = true; |
502 | if (TREE_CODE (list) == STATEMENT_LIST) | |
503 | { | |
504 | tree_stmt_iterator i = tsi_last (list); | |
505 | for (; !tsi_end_p (i); tsi_prev (&i)) | |
506 | { | |
507 | tree t = tsi_stmt (i); | |
508 | if (t == last) | |
509 | break; | |
510 | if (!check_constexpr_ctor_body_1 (last, t)) | |
511 | { | |
512 | ok = false; | |
513 | break; | |
514 | } | |
515 | } | |
516 | } | |
517 | else if (list != last | |
518 | && !check_constexpr_ctor_body_1 (last, list)) | |
519 | ok = false; | |
520 | if (!ok) | |
521 | { | |
522 | if (complain) | |
5967b28b | 523 | error ("%<constexpr%> constructor does not have empty body"); |
09b42213 | 524 | DECL_DECLARED_CONSTEXPR_P (current_function_decl) = false; |
525 | } | |
526 | return ok; | |
527 | } | |
528 | ||
529 | /* V is a vector of constructor elements built up for the base and member | |
530 | initializers of a constructor for TYPE. They need to be in increasing | |
531 | offset order, which they might not be yet if TYPE has a primary base | |
532 | which is not first in the base-clause or a vptr and at least one base | |
533 | all of which are non-primary. */ | |
534 | ||
535 | static vec<constructor_elt, va_gc> * | |
536 | sort_constexpr_mem_initializers (tree type, vec<constructor_elt, va_gc> *v) | |
537 | { | |
538 | tree pri = CLASSTYPE_PRIMARY_BINFO (type); | |
539 | tree field_type; | |
540 | unsigned i; | |
541 | constructor_elt *ce; | |
542 | ||
543 | if (pri) | |
544 | field_type = BINFO_TYPE (pri); | |
545 | else if (TYPE_CONTAINS_VPTR_P (type)) | |
546 | field_type = vtbl_ptr_type_node; | |
547 | else | |
548 | return v; | |
549 | ||
550 | /* Find the element for the primary base or vptr and move it to the | |
551 | beginning of the vec. */ | |
552 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
553 | if (TREE_TYPE (ce->index) == field_type) | |
554 | break; | |
555 | ||
556 | if (i > 0 && i < vec_safe_length (v)) | |
557 | { | |
558 | vec<constructor_elt, va_gc> &vref = *v; | |
559 | constructor_elt elt = vref[i]; | |
560 | for (; i > 0; --i) | |
561 | vref[i] = vref[i-1]; | |
562 | vref[0] = elt; | |
563 | } | |
564 | ||
565 | return v; | |
566 | } | |
567 | ||
568 | /* Build compile-time evalable representations of member-initializer list | |
569 | for a constexpr constructor. */ | |
570 | ||
571 | static tree | |
572 | build_constexpr_constructor_member_initializers (tree type, tree body) | |
573 | { | |
574 | vec<constructor_elt, va_gc> *vec = NULL; | |
575 | bool ok = true; | |
816919e1 | 576 | while (true) |
577 | switch (TREE_CODE (body)) | |
578 | { | |
579 | case MUST_NOT_THROW_EXPR: | |
580 | case EH_SPEC_BLOCK: | |
581 | body = TREE_OPERAND (body, 0); | |
582 | break; | |
583 | ||
584 | case STATEMENT_LIST: | |
585 | for (tree_stmt_iterator i = tsi_start (body); | |
586 | !tsi_end_p (i); tsi_next (&i)) | |
587 | { | |
588 | body = tsi_stmt (i); | |
589 | if (TREE_CODE (body) == BIND_EXPR) | |
590 | break; | |
591 | } | |
592 | break; | |
593 | ||
594 | case BIND_EXPR: | |
595 | body = BIND_EXPR_BODY (body); | |
596 | goto found; | |
597 | ||
598 | default: | |
599 | gcc_unreachable (); | |
8a36d0ec | 600 | } |
816919e1 | 601 | found: |
09b42213 | 602 | if (TREE_CODE (body) == CLEANUP_POINT_EXPR) |
603 | { | |
604 | body = TREE_OPERAND (body, 0); | |
605 | if (TREE_CODE (body) == EXPR_STMT) | |
606 | body = TREE_OPERAND (body, 0); | |
607 | if (TREE_CODE (body) == INIT_EXPR | |
608 | && (same_type_ignoring_top_level_qualifiers_p | |
609 | (TREE_TYPE (TREE_OPERAND (body, 0)), | |
610 | current_class_type))) | |
611 | { | |
612 | /* Trivial copy. */ | |
613 | return TREE_OPERAND (body, 1); | |
614 | } | |
615 | ok = build_data_member_initialization (body, &vec); | |
616 | } | |
617 | else if (TREE_CODE (body) == STATEMENT_LIST) | |
618 | { | |
619 | tree_stmt_iterator i; | |
620 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
621 | { | |
622 | ok = build_data_member_initialization (tsi_stmt (i), &vec); | |
623 | if (!ok) | |
624 | break; | |
625 | } | |
626 | } | |
627 | else if (TREE_CODE (body) == TRY_BLOCK) | |
628 | { | |
629 | error ("body of %<constexpr%> constructor cannot be " | |
630 | "a function-try-block"); | |
631 | return error_mark_node; | |
632 | } | |
633 | else if (EXPR_P (body)) | |
634 | ok = build_data_member_initialization (body, &vec); | |
635 | else | |
636 | gcc_assert (errorcount > 0); | |
637 | if (ok) | |
638 | { | |
639 | if (vec_safe_length (vec) > 0) | |
640 | { | |
641 | /* In a delegating constructor, return the target. */ | |
642 | constructor_elt *ce = &(*vec)[0]; | |
643 | if (ce->index == current_class_ptr) | |
644 | { | |
645 | body = ce->value; | |
646 | vec_free (vec); | |
647 | return body; | |
648 | } | |
649 | } | |
650 | vec = sort_constexpr_mem_initializers (type, vec); | |
651 | return build_constructor (type, vec); | |
652 | } | |
653 | else | |
654 | return error_mark_node; | |
655 | } | |
656 | ||
2fb20ba2 | 657 | /* We have an expression tree T that represents a call, either CALL_EXPR |
658 | or AGGR_INIT_EXPR. If the call is lexically to a named function, | |
659 | retrun the _DECL for that function. */ | |
660 | ||
661 | static tree | |
662 | get_function_named_in_call (tree t) | |
663 | { | |
664 | tree fun = cp_get_callee (t); | |
665 | if (fun && TREE_CODE (fun) == ADDR_EXPR | |
666 | && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL) | |
667 | fun = TREE_OPERAND (fun, 0); | |
668 | return fun; | |
669 | } | |
670 | ||
09b42213 | 671 | /* Subroutine of register_constexpr_fundef. BODY is the body of a function |
672 | declared to be constexpr, or a sub-statement thereof. Returns the | |
673 | return value if suitable, error_mark_node for a statement not allowed in | |
674 | a constexpr function, or NULL_TREE if no return value was found. */ | |
675 | ||
c49bd35e | 676 | tree |
09b42213 | 677 | constexpr_fn_retval (tree body) |
678 | { | |
679 | switch (TREE_CODE (body)) | |
680 | { | |
681 | case STATEMENT_LIST: | |
682 | { | |
683 | tree_stmt_iterator i; | |
684 | tree expr = NULL_TREE; | |
685 | for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i)) | |
686 | { | |
687 | tree s = constexpr_fn_retval (tsi_stmt (i)); | |
688 | if (s == error_mark_node) | |
689 | return error_mark_node; | |
690 | else if (s == NULL_TREE) | |
691 | /* Keep iterating. */; | |
692 | else if (expr) | |
693 | /* Multiple return statements. */ | |
694 | return error_mark_node; | |
695 | else | |
696 | expr = s; | |
697 | } | |
698 | return expr; | |
699 | } | |
700 | ||
701 | case RETURN_EXPR: | |
702 | return break_out_target_exprs (TREE_OPERAND (body, 0)); | |
703 | ||
704 | case DECL_EXPR: | |
394aed6a | 705 | { |
706 | tree decl = DECL_EXPR_DECL (body); | |
707 | if (TREE_CODE (decl) == USING_DECL | |
708 | /* Accept __func__, __FUNCTION__, and __PRETTY_FUNCTION__. */ | |
709 | || DECL_ARTIFICIAL (decl)) | |
710 | return NULL_TREE; | |
711 | return error_mark_node; | |
712 | } | |
09b42213 | 713 | |
714 | case CLEANUP_POINT_EXPR: | |
715 | return constexpr_fn_retval (TREE_OPERAND (body, 0)); | |
716 | ||
717 | case BIND_EXPR: | |
718 | if (!check_constexpr_bind_expr_vars (body)) | |
719 | return error_mark_node; | |
720 | return constexpr_fn_retval (BIND_EXPR_BODY (body)); | |
721 | ||
722 | case USING_STMT: | |
90567983 | 723 | case DEBUG_BEGIN_STMT: |
09b42213 | 724 | return NULL_TREE; |
725 | ||
2fb20ba2 | 726 | case CALL_EXPR: |
727 | { | |
728 | tree fun = get_function_named_in_call (body); | |
729 | if (fun != NULL_TREE | |
a0e9bfbb | 730 | && fndecl_built_in_p (fun, BUILT_IN_UNREACHABLE)) |
2fb20ba2 | 731 | return NULL_TREE; |
732 | } | |
733 | /* Fallthru. */ | |
734 | ||
09b42213 | 735 | default: |
736 | return error_mark_node; | |
737 | } | |
738 | } | |
739 | ||
740 | /* Subroutine of register_constexpr_fundef. BODY is the DECL_SAVED_TREE of | |
741 | FUN; do the necessary transformations to turn it into a single expression | |
742 | that we can store in the hash table. */ | |
743 | ||
744 | static tree | |
745 | massage_constexpr_body (tree fun, tree body) | |
746 | { | |
747 | if (DECL_CONSTRUCTOR_P (fun)) | |
748 | body = build_constexpr_constructor_member_initializers | |
749 | (DECL_CONTEXT (fun), body); | |
9c96033c | 750 | else if (cxx_dialect < cxx14) |
09b42213 | 751 | { |
752 | if (TREE_CODE (body) == EH_SPEC_BLOCK) | |
753 | body = EH_SPEC_STMTS (body); | |
754 | if (TREE_CODE (body) == MUST_NOT_THROW_EXPR) | |
755 | body = TREE_OPERAND (body, 0); | |
756 | body = constexpr_fn_retval (body); | |
757 | } | |
758 | return body; | |
759 | } | |
760 | ||
2f4cab3c | 761 | /* CTYPE is a type constructed from BODY. Return true if some |
762 | bases/fields are uninitialized, and complain if COMPLAIN. */ | |
09b42213 | 763 | |
764 | static bool | |
2f4cab3c | 765 | cx_check_missing_mem_inits (tree ctype, tree body, bool complain) |
09b42213 | 766 | { |
2f4cab3c | 767 | unsigned nelts = 0; |
768 | ||
769 | if (body) | |
770 | { | |
771 | if (TREE_CODE (body) != CONSTRUCTOR) | |
772 | return false; | |
773 | nelts = CONSTRUCTOR_NELTS (body); | |
774 | } | |
775 | tree field = TYPE_FIELDS (ctype); | |
09b42213 | 776 | |
777 | if (TREE_CODE (ctype) == UNION_TYPE) | |
778 | { | |
779 | if (nelts == 0 && next_initializable_field (field)) | |
780 | { | |
781 | if (complain) | |
782 | error ("%<constexpr%> constructor for union %qT must " | |
783 | "initialize exactly one non-static data member", ctype); | |
784 | return true; | |
785 | } | |
786 | return false; | |
787 | } | |
788 | ||
2f4cab3c | 789 | /* Iterate over the CONSTRUCTOR, checking any missing fields don't |
790 | need an explicit initialization. */ | |
791 | bool bad = false; | |
792 | for (unsigned i = 0; i <= nelts; ++i) | |
09b42213 | 793 | { |
2f4cab3c | 794 | tree index = NULL_TREE; |
795 | if (i < nelts) | |
09b42213 | 796 | { |
797 | index = CONSTRUCTOR_ELT (body, i)->index; | |
798 | /* Skip base and vtable inits. */ | |
799 | if (TREE_CODE (index) != FIELD_DECL | |
800 | || DECL_ARTIFICIAL (index)) | |
801 | continue; | |
802 | } | |
2f4cab3c | 803 | |
09b42213 | 804 | for (; field != index; field = DECL_CHAIN (field)) |
805 | { | |
806 | tree ftype; | |
2f4cab3c | 807 | if (TREE_CODE (field) != FIELD_DECL) |
808 | continue; | |
3cde3c29 | 809 | if (DECL_UNNAMED_BIT_FIELD (field)) |
09b42213 | 810 | continue; |
2f4cab3c | 811 | if (DECL_ARTIFICIAL (field)) |
812 | continue; | |
813 | if (ANON_AGGR_TYPE_P (TREE_TYPE (field))) | |
814 | { | |
815 | /* Recurse to check the anonummous aggregate member. */ | |
816 | bad |= cx_check_missing_mem_inits | |
817 | (TREE_TYPE (field), NULL_TREE, complain); | |
818 | if (bad && !complain) | |
819 | return true; | |
820 | continue; | |
821 | } | |
09b42213 | 822 | ftype = strip_array_types (TREE_TYPE (field)); |
823 | if (type_has_constexpr_default_constructor (ftype)) | |
824 | { | |
825 | /* It's OK to skip a member with a trivial constexpr ctor. | |
826 | A constexpr ctor that isn't trivial should have been | |
827 | added in by now. */ | |
828 | gcc_checking_assert (!TYPE_HAS_COMPLEX_DFLT (ftype) | |
829 | || errorcount != 0); | |
830 | continue; | |
831 | } | |
832 | if (!complain) | |
833 | return true; | |
bc35ef65 | 834 | auto_diagnostic_group d; |
859e2c29 | 835 | error ("member %qD must be initialized by mem-initializer " |
836 | "in %<constexpr%> constructor", field); | |
837 | inform (DECL_SOURCE_LOCATION (field), "declared here"); | |
09b42213 | 838 | bad = true; |
839 | } | |
840 | if (field == NULL_TREE) | |
841 | break; | |
2f4cab3c | 842 | |
843 | if (ANON_AGGR_TYPE_P (TREE_TYPE (index))) | |
844 | { | |
845 | /* Check the anonymous aggregate initializer is valid. */ | |
846 | bad |= cx_check_missing_mem_inits | |
847 | (TREE_TYPE (index), CONSTRUCTOR_ELT (body, i)->value, complain); | |
848 | if (bad && !complain) | |
849 | return true; | |
850 | } | |
09b42213 | 851 | field = DECL_CHAIN (field); |
852 | } | |
853 | ||
854 | return bad; | |
855 | } | |
856 | ||
857 | /* We are processing the definition of the constexpr function FUN. | |
858 | Check that its BODY fulfills the propriate requirements and | |
859 | enter it in the constexpr function definition table. | |
860 | For constructor BODY is actually the TREE_LIST of the | |
861 | member-initializer list. */ | |
862 | ||
863 | tree | |
864 | register_constexpr_fundef (tree fun, tree body) | |
865 | { | |
866 | constexpr_fundef entry; | |
867 | constexpr_fundef **slot; | |
868 | ||
869 | if (!is_valid_constexpr_fn (fun, !DECL_GENERATED_P (fun))) | |
870 | return NULL; | |
871 | ||
6a385150 | 872 | tree massaged = massage_constexpr_body (fun, body); |
873 | if (massaged == NULL_TREE || massaged == error_mark_node) | |
09b42213 | 874 | { |
875 | if (!DECL_CONSTRUCTOR_P (fun)) | |
5967b28b | 876 | error ("body of %<constexpr%> function %qD not a return-statement", |
877 | fun); | |
09b42213 | 878 | return NULL; |
879 | } | |
880 | ||
6a385150 | 881 | if (!potential_rvalue_constant_expression (massaged)) |
09b42213 | 882 | { |
883 | if (!DECL_GENERATED_P (fun)) | |
6a385150 | 884 | require_potential_rvalue_constant_expression (massaged); |
09b42213 | 885 | return NULL; |
886 | } | |
887 | ||
888 | if (DECL_CONSTRUCTOR_P (fun) | |
2f4cab3c | 889 | && cx_check_missing_mem_inits (DECL_CONTEXT (fun), |
890 | massaged, !DECL_GENERATED_P (fun))) | |
09b42213 | 891 | return NULL; |
892 | ||
893 | /* Create the constexpr function table if necessary. */ | |
894 | if (constexpr_fundef_table == NULL) | |
895 | constexpr_fundef_table | |
896 | = hash_table<constexpr_fundef_hasher>::create_ggc (101); | |
897 | ||
898 | entry.decl = fun; | |
899 | entry.body = body; | |
900 | slot = constexpr_fundef_table->find_slot (&entry, INSERT); | |
901 | ||
902 | gcc_assert (*slot == NULL); | |
903 | *slot = ggc_alloc<constexpr_fundef> (); | |
904 | **slot = entry; | |
905 | ||
906 | return fun; | |
907 | } | |
908 | ||
909 | /* FUN is a non-constexpr function called in a context that requires a | |
910 | constant expression. If it comes from a constexpr template, explain why | |
911 | the instantiation isn't constexpr. */ | |
912 | ||
913 | void | |
914 | explain_invalid_constexpr_fn (tree fun) | |
915 | { | |
916 | static hash_set<tree> *diagnosed; | |
917 | tree body; | |
918 | location_t save_loc; | |
33603066 | 919 | /* Only diagnose defaulted functions, lambdas, or instantiations. */ |
09b42213 | 920 | if (!DECL_DEFAULTED_FN (fun) |
33603066 | 921 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) |
09b42213 | 922 | && !is_instantiation_of_constexpr (fun)) |
923 | return; | |
924 | if (diagnosed == NULL) | |
925 | diagnosed = new hash_set<tree>; | |
926 | if (diagnosed->add (fun)) | |
927 | /* Already explained. */ | |
928 | return; | |
929 | ||
930 | save_loc = input_location; | |
33603066 | 931 | if (!lambda_static_thunk_p (fun)) |
932 | { | |
933 | /* Diagnostics should completely ignore the static thunk, so leave | |
934 | input_location set to our caller's location. */ | |
935 | input_location = DECL_SOURCE_LOCATION (fun); | |
936 | inform (input_location, | |
5967b28b | 937 | "%qD is not usable as a %<constexpr%> function because:", fun); |
33603066 | 938 | } |
09b42213 | 939 | /* First check the declaration. */ |
940 | if (is_valid_constexpr_fn (fun, true)) | |
941 | { | |
942 | /* Then if it's OK, the body. */ | |
33603066 | 943 | if (!DECL_DECLARED_CONSTEXPR_P (fun) |
944 | && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun))) | |
09b42213 | 945 | explain_implicit_non_constexpr (fun); |
946 | else | |
947 | { | |
948 | body = massage_constexpr_body (fun, DECL_SAVED_TREE (fun)); | |
949 | require_potential_rvalue_constant_expression (body); | |
950 | if (DECL_CONSTRUCTOR_P (fun)) | |
2f4cab3c | 951 | cx_check_missing_mem_inits (DECL_CONTEXT (fun), body, true); |
09b42213 | 952 | } |
953 | } | |
954 | input_location = save_loc; | |
955 | } | |
956 | ||
957 | /* Objects of this type represent calls to constexpr functions | |
958 | along with the bindings of parameters to their arguments, for | |
959 | the purpose of compile time evaluation. */ | |
960 | ||
961 | struct GTY((for_user)) constexpr_call { | |
962 | /* Description of the constexpr function definition. */ | |
963 | constexpr_fundef *fundef; | |
964 | /* Parameter bindings environment. A TREE_LIST where each TREE_PURPOSE | |
965 | is a parameter _DECL and the TREE_VALUE is the value of the parameter. | |
966 | Note: This arrangement is made to accommodate the use of | |
967 | iterative_hash_template_arg (see pt.c). If you change this | |
968 | representation, also change the hash calculation in | |
969 | cxx_eval_call_expression. */ | |
970 | tree bindings; | |
971 | /* Result of the call. | |
972 | NULL means the call is being evaluated. | |
973 | error_mark_node means that the evaluation was erroneous; | |
974 | otherwise, the actuall value of the call. */ | |
975 | tree result; | |
976 | /* The hash of this call; we remember it here to avoid having to | |
977 | recalculate it when expanding the hash table. */ | |
978 | hashval_t hash; | |
919873c7 | 979 | /* Whether __builtin_is_constant_evaluated() should evaluate to true. */ |
1562c831 | 980 | bool manifestly_const_eval; |
09b42213 | 981 | }; |
982 | ||
b594087e | 983 | struct constexpr_call_hasher : ggc_ptr_hash<constexpr_call> |
09b42213 | 984 | { |
985 | static hashval_t hash (constexpr_call *); | |
986 | static bool equal (constexpr_call *, constexpr_call *); | |
cf72f34d | 987 | }; |
988 | ||
2a2770c6 | 989 | enum constexpr_switch_state { |
990 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
991 | and default: label for that switch has not been seen yet. */ | |
992 | css_default_not_seen, | |
993 | /* Used when processing a switch for the first time by cxx_eval_switch_expr | |
994 | and default: label for that switch has been seen already. */ | |
995 | css_default_seen, | |
996 | /* Used when processing a switch for the second time by | |
997 | cxx_eval_switch_expr, where default: label should match. */ | |
998 | css_default_processing | |
999 | }; | |
1000 | ||
cf72f34d | 1001 | /* The constexpr expansion context. CALL is the current function |
1002 | expansion, CTOR is the current aggregate initializer, OBJECT is the | |
1003 | object being initialized by CTOR, either a VAR_DECL or a _REF. VALUES | |
1004 | is a map of values of variables initialized within the expression. */ | |
1005 | ||
1006 | struct constexpr_ctx { | |
f9885b8a | 1007 | /* The innermost call we're evaluating. */ |
cf72f34d | 1008 | constexpr_call *call; |
f9885b8a | 1009 | /* Values for any temporaries or local variables within the |
1010 | constant-expression. */ | |
cf72f34d | 1011 | hash_map<tree,tree> *values; |
2631cb67 | 1012 | /* SAVE_EXPRs that we've seen within the current LOOP_EXPR. NULL if we |
1013 | aren't inside a loop. */ | |
1014 | hash_set<tree> *save_exprs; | |
f9885b8a | 1015 | /* The CONSTRUCTOR we're currently building up for an aggregate |
1016 | initializer. */ | |
cf72f34d | 1017 | tree ctor; |
f9885b8a | 1018 | /* The object we're building the CONSTRUCTOR for. */ |
cf72f34d | 1019 | tree object; |
2a2770c6 | 1020 | /* If inside SWITCH_EXPR. */ |
1021 | constexpr_switch_state *css_state; | |
f9885b8a | 1022 | /* Whether we should error on a non-constant expression or fail quietly. */ |
f83e6885 | 1023 | bool quiet; |
f9885b8a | 1024 | /* Whether we are strictly conforming to constant expression rules or |
1025 | trying harder to get a constant value. */ | |
2055d27a | 1026 | bool strict; |
18d371d3 | 1027 | /* Whether __builtin_is_constant_evaluated () should be true. */ |
1562c831 | 1028 | bool manifestly_const_eval; |
cf72f34d | 1029 | }; |
09b42213 | 1030 | |
1031 | /* A table of all constexpr calls that have been evaluated by the | |
1032 | compiler in this translation unit. */ | |
1033 | ||
a050099a | 1034 | static GTY (()) hash_table<constexpr_call_hasher> *constexpr_call_table; |
09b42213 | 1035 | |
cf72f34d | 1036 | static tree cxx_eval_constant_expression (const constexpr_ctx *, tree, |
b2a43197 | 1037 | bool, bool *, bool *, tree * = NULL); |
09b42213 | 1038 | |
1039 | /* Compute a hash value for a constexpr call representation. */ | |
1040 | ||
1041 | inline hashval_t | |
1042 | constexpr_call_hasher::hash (constexpr_call *info) | |
1043 | { | |
1044 | return info->hash; | |
1045 | } | |
1046 | ||
1047 | /* Return true if the objects pointed to by P and Q represent calls | |
1048 | to the same constexpr function with the same arguments. | |
1049 | Otherwise, return false. */ | |
1050 | ||
1051 | bool | |
1052 | constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs) | |
1053 | { | |
1054 | tree lhs_bindings; | |
1055 | tree rhs_bindings; | |
1056 | if (lhs == rhs) | |
c751e2cd | 1057 | return true; |
1058 | if (lhs->hash != rhs->hash) | |
1059 | return false; | |
1562c831 | 1060 | if (lhs->manifestly_const_eval != rhs->manifestly_const_eval) |
919873c7 | 1061 | return false; |
09b42213 | 1062 | if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef)) |
c751e2cd | 1063 | return false; |
09b42213 | 1064 | lhs_bindings = lhs->bindings; |
1065 | rhs_bindings = rhs->bindings; | |
1066 | while (lhs_bindings != NULL && rhs_bindings != NULL) | |
1067 | { | |
1068 | tree lhs_arg = TREE_VALUE (lhs_bindings); | |
1069 | tree rhs_arg = TREE_VALUE (rhs_bindings); | |
6d82dbcd | 1070 | gcc_assert (same_type_p (TREE_TYPE (lhs_arg), TREE_TYPE (rhs_arg))); |
09b42213 | 1071 | if (!cp_tree_equal (lhs_arg, rhs_arg)) |
c751e2cd | 1072 | return false; |
09b42213 | 1073 | lhs_bindings = TREE_CHAIN (lhs_bindings); |
1074 | rhs_bindings = TREE_CHAIN (rhs_bindings); | |
1075 | } | |
1076 | return lhs_bindings == rhs_bindings; | |
1077 | } | |
1078 | ||
1079 | /* Initialize the constexpr call table, if needed. */ | |
1080 | ||
1081 | static void | |
1082 | maybe_initialize_constexpr_call_table (void) | |
1083 | { | |
1084 | if (constexpr_call_table == NULL) | |
1085 | constexpr_call_table = hash_table<constexpr_call_hasher>::create_ggc (101); | |
1086 | } | |
1087 | ||
4f7ebe46 | 1088 | /* During constexpr CALL_EXPR evaluation, to avoid issues with sharing when |
1089 | a function happens to get called recursively, we unshare the callee | |
1090 | function's body and evaluate this unshared copy instead of evaluating the | |
1091 | original body. | |
1092 | ||
1093 | FUNDEF_COPIES_TABLE is a per-function freelist of these unshared function | |
1094 | copies. The underlying data structure of FUNDEF_COPIES_TABLE is a hash_map | |
a050099a | 1095 | that's keyed off of the original FUNCTION_DECL and whose value is a |
1096 | TREE_LIST of this function's unused copies awaiting reuse. | |
4f7ebe46 | 1097 | |
a050099a | 1098 | This is not GC-deletable to avoid GC affecting UID generation. */ |
4f7ebe46 | 1099 | |
a050099a | 1100 | static GTY(()) hash_map<tree, tree> *fundef_copies_table; |
4f7ebe46 | 1101 | |
1102 | /* Initialize FUNDEF_COPIES_TABLE if it's not initialized. */ | |
1103 | ||
1104 | static void | |
1105 | maybe_initialize_fundef_copies_table () | |
1106 | { | |
a050099a | 1107 | if (fundef_copies_table == NULL) |
1108 | fundef_copies_table = hash_map<tree,tree>::create_ggc (101); | |
4f7ebe46 | 1109 | } |
1110 | ||
1111 | /* Reuse a copy or create a new unshared copy of the function FUN. | |
886d5463 | 1112 | Return this copy. We use a TREE_LIST whose PURPOSE is body, VALUE |
1113 | is parms, TYPE is result. */ | |
4f7ebe46 | 1114 | |
a050099a | 1115 | static tree |
4f7ebe46 | 1116 | get_fundef_copy (tree fun) |
1117 | { | |
1118 | maybe_initialize_fundef_copies_table (); | |
1119 | ||
a050099a | 1120 | tree copy; |
886d5463 | 1121 | bool existed; |
1122 | tree *slot = &fundef_copies_table->get_or_insert (fun, &existed); | |
1123 | ||
1124 | if (!existed) | |
4f7ebe46 | 1125 | { |
886d5463 | 1126 | /* There is no cached function available, or in use. We can use |
1127 | the function directly. That the slot is now created records | |
1128 | that this function is now in use. */ | |
1129 | copy = build_tree_list (DECL_SAVED_TREE (fun), DECL_ARGUMENTS (fun)); | |
1130 | TREE_TYPE (copy) = DECL_RESULT (fun); | |
1131 | } | |
1132 | else if (*slot == NULL_TREE) | |
1133 | { | |
1134 | /* We've already used the function itself, so make a copy. */ | |
a050099a | 1135 | copy = build_tree_list (NULL, NULL); |
a050099a | 1136 | TREE_PURPOSE (copy) = copy_fn (fun, TREE_VALUE (copy), TREE_TYPE (copy)); |
4f7ebe46 | 1137 | } |
1138 | else | |
1139 | { | |
886d5463 | 1140 | /* We have a cached function available. */ |
4f7ebe46 | 1141 | copy = *slot; |
a050099a | 1142 | *slot = TREE_CHAIN (copy); |
4f7ebe46 | 1143 | } |
1144 | ||
1145 | return copy; | |
1146 | } | |
1147 | ||
886d5463 | 1148 | /* Save the copy COPY of function FUN for later reuse by |
1149 | get_fundef_copy(). By construction, there will always be an entry | |
1150 | to find. */ | |
4f7ebe46 | 1151 | |
1152 | static void | |
a050099a | 1153 | save_fundef_copy (tree fun, tree copy) |
4f7ebe46 | 1154 | { |
886d5463 | 1155 | tree *slot = fundef_copies_table->get (fun); |
a050099a | 1156 | TREE_CHAIN (copy) = *slot; |
4f7ebe46 | 1157 | *slot = copy; |
1158 | } | |
1159 | ||
09b42213 | 1160 | /* We have an expression tree T that represents a call, either CALL_EXPR |
1161 | or AGGR_INIT_EXPR. Return the Nth argument. */ | |
1162 | ||
1163 | static inline tree | |
1164 | get_nth_callarg (tree t, int n) | |
1165 | { | |
1166 | switch (TREE_CODE (t)) | |
1167 | { | |
1168 | case CALL_EXPR: | |
1169 | return CALL_EXPR_ARG (t, n); | |
1170 | ||
1171 | case AGGR_INIT_EXPR: | |
1172 | return AGGR_INIT_EXPR_ARG (t, n); | |
1173 | ||
1174 | default: | |
1175 | gcc_unreachable (); | |
1176 | return NULL; | |
1177 | } | |
1178 | } | |
1179 | ||
09b42213 | 1180 | /* Attempt to evaluate T which represents a call to a builtin function. |
1181 | We assume here that all builtin functions evaluate to scalar types | |
1182 | represented by _CST nodes. */ | |
1183 | ||
1184 | static tree | |
f1c6af10 | 1185 | cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, |
1227ba74 | 1186 | bool lval, |
09b42213 | 1187 | bool *non_constant_p, bool *overflow_p) |
1188 | { | |
1189 | const int nargs = call_expr_nargs (t); | |
1190 | tree *args = (tree *) alloca (nargs * sizeof (tree)); | |
1191 | tree new_call; | |
1192 | int i; | |
f1c6af10 | 1193 | |
1194 | /* Don't fold __builtin_constant_p within a constexpr function. */ | |
18d371d3 | 1195 | bool bi_const_p = DECL_IS_BUILTIN_CONSTANT_P (fun); |
efe6a40a | 1196 | |
0f5cec54 | 1197 | /* If we aren't requiring a constant expression, defer __builtin_constant_p |
1198 | in a constexpr function until we have values for the parameters. */ | |
efe6a40a | 1199 | if (bi_const_p |
0f5cec54 | 1200 | && ctx->quiet |
f1c6af10 | 1201 | && current_function_decl |
1202 | && DECL_DECLARED_CONSTEXPR_P (current_function_decl)) | |
09b42213 | 1203 | { |
f1c6af10 | 1204 | *non_constant_p = true; |
1205 | return t; | |
09b42213 | 1206 | } |
f1c6af10 | 1207 | |
18d371d3 | 1208 | /* For __builtin_is_constant_evaluated, defer it if not |
1562c831 | 1209 | ctx->manifestly_const_eval, otherwise fold it to true. */ |
a0e9bfbb | 1210 | if (fndecl_built_in_p (fun, CP_BUILT_IN_IS_CONSTANT_EVALUATED, |
1562c831 | 1211 | BUILT_IN_FRONTEND)) |
18d371d3 | 1212 | { |
1562c831 | 1213 | if (!ctx->manifestly_const_eval) |
18d371d3 | 1214 | { |
1215 | *non_constant_p = true; | |
1216 | return t; | |
1217 | } | |
1218 | return boolean_true_node; | |
1219 | } | |
1220 | ||
f1c6af10 | 1221 | /* Be permissive for arguments to built-ins; __builtin_constant_p should |
1222 | return constant false for a non-constant argument. */ | |
1223 | constexpr_ctx new_ctx = *ctx; | |
1224 | new_ctx.quiet = true; | |
1225 | bool dummy1 = false, dummy2 = false; | |
1226 | for (i = 0; i < nargs; ++i) | |
efe6a40a | 1227 | { |
91b66c3c | 1228 | args[i] = CALL_EXPR_ARG (t, i); |
1229 | /* If builtin_valid_in_constant_expr_p is true, | |
1230 | potential_constant_expression_1 has not recursed into the arguments | |
1231 | of the builtin, verify it here. */ | |
1232 | if (!builtin_valid_in_constant_expr_p (fun) | |
1233 | || potential_constant_expression (args[i])) | |
1234 | args[i] = cxx_eval_constant_expression (&new_ctx, args[i], false, | |
1235 | &dummy1, &dummy2); | |
efe6a40a | 1236 | if (bi_const_p) |
1237 | /* For __built_in_constant_p, fold all expressions with constant values | |
1238 | even if they aren't C++ constant-expressions. */ | |
1239 | args[i] = cp_fully_fold (args[i]); | |
1240 | } | |
f1c6af10 | 1241 | |
1242 | bool save_ffbcp = force_folding_builtin_constant_p; | |
1243 | force_folding_builtin_constant_p = true; | |
051eb924 | 1244 | new_call = fold_builtin_call_array (EXPR_LOCATION (t), TREE_TYPE (t), |
1245 | CALL_EXPR_FN (t), nargs, args); | |
f1c6af10 | 1246 | force_folding_builtin_constant_p = save_ffbcp; |
051eb924 | 1247 | if (new_call == NULL) |
1248 | { | |
1249 | if (!*non_constant_p && !ctx->quiet) | |
1250 | { | |
2fb20ba2 | 1251 | /* Do not allow__builtin_unreachable in constexpr function. |
1252 | The __builtin_unreachable call with BUILTINS_LOCATION | |
1253 | comes from cp_maybe_instrument_return. */ | |
a0e9bfbb | 1254 | if (fndecl_built_in_p (fun, BUILT_IN_UNREACHABLE) |
2fb20ba2 | 1255 | && EXPR_LOCATION (t) == BUILTINS_LOCATION) |
5967b28b | 1256 | error ("%<constexpr%> call flows off the end of the function"); |
2fb20ba2 | 1257 | else |
1258 | { | |
1259 | new_call = build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t), | |
1260 | CALL_EXPR_FN (t), nargs, args); | |
1261 | error ("%q+E is not a constant expression", new_call); | |
1262 | } | |
051eb924 | 1263 | } |
1264 | *non_constant_p = true; | |
1265 | return t; | |
1266 | } | |
1267 | ||
7e1f8be4 | 1268 | if (!is_constant_expression (new_call)) |
051eb924 | 1269 | { |
1270 | if (!*non_constant_p && !ctx->quiet) | |
1271 | error ("%q+E is not a constant expression", new_call); | |
1272 | *non_constant_p = true; | |
1273 | return t; | |
1274 | } | |
1275 | ||
1276 | return cxx_eval_constant_expression (&new_ctx, new_call, lval, | |
1277 | non_constant_p, overflow_p); | |
09b42213 | 1278 | } |
1279 | ||
1280 | /* TEMP is the constant value of a temporary object of type TYPE. Adjust | |
1281 | the type of the value to match. */ | |
1282 | ||
1283 | static tree | |
1284 | adjust_temp_type (tree type, tree temp) | |
1285 | { | |
6d82dbcd | 1286 | if (same_type_p (TREE_TYPE (temp), type)) |
09b42213 | 1287 | return temp; |
1288 | /* Avoid wrapping an aggregate value in a NOP_EXPR. */ | |
1289 | if (TREE_CODE (temp) == CONSTRUCTOR) | |
1290 | return build_constructor (type, CONSTRUCTOR_ELTS (temp)); | |
71c3d84e | 1291 | if (TREE_CODE (temp) == EMPTY_CLASS_EXPR) |
1292 | return build0 (EMPTY_CLASS_EXPR, type); | |
09b42213 | 1293 | gcc_assert (scalarish_type_p (type)); |
1294 | return cp_fold_convert (type, temp); | |
1295 | } | |
1296 | ||
e283bb4f | 1297 | /* Callback for walk_tree used by unshare_constructor. */ |
1298 | ||
1299 | static tree | |
1300 | find_constructor (tree *tp, int *walk_subtrees, void *) | |
1301 | { | |
1302 | if (TYPE_P (*tp)) | |
1303 | *walk_subtrees = 0; | |
1304 | if (TREE_CODE (*tp) == CONSTRUCTOR) | |
1305 | return *tp; | |
1306 | return NULL_TREE; | |
1307 | } | |
1308 | ||
1309 | /* If T is a CONSTRUCTOR or an expression that has a CONSTRUCTOR node as a | |
1310 | subexpression, return an unshared copy of T. Otherwise return T. */ | |
1311 | ||
1312 | static tree | |
1313 | unshare_constructor (tree t) | |
1314 | { | |
1315 | tree ctor = walk_tree (&t, find_constructor, NULL, NULL); | |
1316 | if (ctor != NULL_TREE) | |
1317 | return unshare_expr (t); | |
1318 | return t; | |
1319 | } | |
1320 | ||
09b42213 | 1321 | /* Subroutine of cxx_eval_call_expression. |
1322 | We are processing a call expression (either CALL_EXPR or | |
cf72f34d | 1323 | AGGR_INIT_EXPR) in the context of CTX. Evaluate |
09b42213 | 1324 | all arguments and bind their values to correspondings |
1325 | parameters, making up the NEW_CALL context. */ | |
1326 | ||
1327 | static void | |
cf72f34d | 1328 | cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, |
09b42213 | 1329 | constexpr_call *new_call, |
c8f6aeb1 | 1330 | bool *non_constant_p, bool *overflow_p, |
1331 | bool *non_constant_args) | |
09b42213 | 1332 | { |
1333 | const int nargs = call_expr_nargs (t); | |
1334 | tree fun = new_call->fundef->decl; | |
1335 | tree parms = DECL_ARGUMENTS (fun); | |
1336 | int i; | |
9c96033c | 1337 | tree *p = &new_call->bindings; |
09b42213 | 1338 | for (i = 0; i < nargs; ++i) |
1339 | { | |
1340 | tree x, arg; | |
1341 | tree type = parms ? TREE_TYPE (parms) : void_type_node; | |
09b42213 | 1342 | x = get_nth_callarg (t, i); |
cf72f34d | 1343 | /* For member function, the first argument is a pointer to the implied |
1344 | object. For a constructor, it might still be a dummy object, in | |
9c96033c | 1345 | which case we get the real argument from ctx. */ |
cf72f34d | 1346 | if (i == 0 && DECL_CONSTRUCTOR_P (fun) |
1347 | && is_dummy_object (x)) | |
1348 | { | |
1349 | x = ctx->object; | |
c017458d | 1350 | x = build_address (x); |
cf72f34d | 1351 | } |
2e1c71c2 | 1352 | arg = cxx_eval_constant_expression (ctx, x, /*lval=*/false, |
b2a43197 | 1353 | non_constant_p, overflow_p); |
09b42213 | 1354 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 1355 | if (*non_constant_p && ctx->quiet) |
09b42213 | 1356 | return; |
1357 | /* Just discard ellipsis args after checking their constantitude. */ | |
1358 | if (!parms) | |
1359 | continue; | |
2ba934c7 | 1360 | |
1361 | if (!*non_constant_p) | |
1362 | { | |
24d5b4f0 | 1363 | /* Don't share a CONSTRUCTOR that might be changed. */ |
1364 | arg = unshare_constructor (arg); | |
2ba934c7 | 1365 | /* Make sure the binding has the same type as the parm. But |
1366 | only for constant args. */ | |
90ad495b | 1367 | if (!TYPE_REF_P (type)) |
2ba934c7 | 1368 | arg = adjust_temp_type (type, arg); |
1369 | if (!TREE_CONSTANT (arg)) | |
1370 | *non_constant_args = true; | |
1371 | *p = build_tree_list (parms, arg); | |
1372 | p = &TREE_CHAIN (*p); | |
1373 | } | |
09b42213 | 1374 | parms = TREE_CHAIN (parms); |
1375 | } | |
1376 | } | |
1377 | ||
1378 | /* Variables and functions to manage constexpr call expansion context. | |
1379 | These do not need to be marked for PCH or GC. */ | |
1380 | ||
1381 | /* FIXME remember and print actual constant arguments. */ | |
16fb756f | 1382 | static vec<tree> call_stack; |
09b42213 | 1383 | static int call_stack_tick; |
1384 | static int last_cx_error_tick; | |
1385 | ||
1386 | static bool | |
1387 | push_cx_call_context (tree call) | |
1388 | { | |
1389 | ++call_stack_tick; | |
1390 | if (!EXPR_HAS_LOCATION (call)) | |
1391 | SET_EXPR_LOCATION (call, input_location); | |
1392 | call_stack.safe_push (call); | |
1393 | if (call_stack.length () > (unsigned) max_constexpr_depth) | |
1394 | return false; | |
1395 | return true; | |
1396 | } | |
1397 | ||
1398 | static void | |
1399 | pop_cx_call_context (void) | |
1400 | { | |
1401 | ++call_stack_tick; | |
1402 | call_stack.pop (); | |
1403 | } | |
1404 | ||
1405 | vec<tree> | |
1406 | cx_error_context (void) | |
1407 | { | |
1408 | vec<tree> r = vNULL; | |
1409 | if (call_stack_tick != last_cx_error_tick | |
1410 | && !call_stack.is_empty ()) | |
1411 | r = call_stack; | |
1412 | last_cx_error_tick = call_stack_tick; | |
1413 | return r; | |
1414 | } | |
1415 | ||
732905bb | 1416 | /* Evaluate a call T to a GCC internal function when possible and return |
1417 | the evaluated result or, under the control of CTX, give an error, set | |
1418 | NON_CONSTANT_P, and return the unevaluated call T otherwise. */ | |
1419 | ||
1420 | static tree | |
1421 | cxx_eval_internal_function (const constexpr_ctx *ctx, tree t, | |
1422 | bool lval, | |
1423 | bool *non_constant_p, bool *overflow_p) | |
1424 | { | |
1425 | enum tree_code opcode = ERROR_MARK; | |
1426 | ||
1427 | switch (CALL_EXPR_IFN (t)) | |
1428 | { | |
1429 | case IFN_UBSAN_NULL: | |
1430 | case IFN_UBSAN_BOUNDS: | |
1431 | case IFN_UBSAN_VPTR: | |
3c77f69c | 1432 | case IFN_FALLTHROUGH: |
732905bb | 1433 | return void_node; |
1434 | ||
1435 | case IFN_ADD_OVERFLOW: | |
1436 | opcode = PLUS_EXPR; | |
1437 | break; | |
1438 | case IFN_SUB_OVERFLOW: | |
1439 | opcode = MINUS_EXPR; | |
1440 | break; | |
1441 | case IFN_MUL_OVERFLOW: | |
1442 | opcode = MULT_EXPR; | |
1443 | break; | |
1444 | ||
6e1b2ffb | 1445 | case IFN_LAUNDER: |
1446 | return cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), | |
1447 | false, non_constant_p, overflow_p); | |
1448 | ||
732905bb | 1449 | default: |
1450 | if (!ctx->quiet) | |
d3a3cfb8 | 1451 | error_at (cp_expr_loc_or_loc (t, input_location), |
732905bb | 1452 | "call to internal function %qE", t); |
1453 | *non_constant_p = true; | |
1454 | return t; | |
1455 | } | |
1456 | ||
1457 | /* Evaluate constant arguments using OPCODE and return a complex | |
1458 | number containing the result and the overflow bit. */ | |
1459 | tree arg0 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), lval, | |
1460 | non_constant_p, overflow_p); | |
1461 | tree arg1 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 1), lval, | |
1462 | non_constant_p, overflow_p); | |
1463 | ||
1464 | if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) | |
1465 | { | |
d3a3cfb8 | 1466 | location_t loc = cp_expr_loc_or_loc (t, input_location); |
732905bb | 1467 | tree type = TREE_TYPE (TREE_TYPE (t)); |
1468 | tree result = fold_binary_loc (loc, opcode, type, | |
1469 | fold_convert_loc (loc, type, arg0), | |
1470 | fold_convert_loc (loc, type, arg1)); | |
1471 | tree ovf | |
1472 | = build_int_cst (type, arith_overflowed_p (opcode, type, arg0, arg1)); | |
1473 | /* Reset TREE_OVERFLOW to avoid warnings for the overflow. */ | |
1474 | if (TREE_OVERFLOW (result)) | |
1475 | TREE_OVERFLOW (result) = 0; | |
1476 | ||
1477 | return build_complex (TREE_TYPE (t), result, ovf); | |
1478 | } | |
1479 | ||
1480 | *non_constant_p = true; | |
1481 | return t; | |
1482 | } | |
1483 | ||
165d0d5b | 1484 | /* Clean CONSTRUCTOR_NO_CLEARING from CTOR and its sub-aggregates. */ |
79cdb4f5 | 1485 | |
1486 | static void | |
1487 | clear_no_implicit_zero (tree ctor) | |
1488 | { | |
165d0d5b | 1489 | if (CONSTRUCTOR_NO_CLEARING (ctor)) |
79cdb4f5 | 1490 | { |
165d0d5b | 1491 | CONSTRUCTOR_NO_CLEARING (ctor) = false; |
79cdb4f5 | 1492 | tree elt; unsigned HOST_WIDE_INT idx; |
1493 | FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (ctor), idx, elt) | |
1494 | if (TREE_CODE (elt) == CONSTRUCTOR) | |
1495 | clear_no_implicit_zero (elt); | |
1496 | } | |
1497 | } | |
1498 | ||
09b42213 | 1499 | /* Subroutine of cxx_eval_constant_expression. |
1500 | Evaluate the call expression tree T in the context of OLD_CALL expression | |
1501 | evaluation. */ | |
1502 | ||
1503 | static tree | |
cf72f34d | 1504 | cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 1505 | bool lval, |
09b42213 | 1506 | bool *non_constant_p, bool *overflow_p) |
1507 | { | |
d3a3cfb8 | 1508 | location_t loc = cp_expr_loc_or_loc (t, input_location); |
09b42213 | 1509 | tree fun = get_function_named_in_call (t); |
919873c7 | 1510 | constexpr_call new_call |
1562c831 | 1511 | = { NULL, NULL, NULL, 0, ctx->manifestly_const_eval }; |
09b42213 | 1512 | bool depth_ok; |
1513 | ||
6b71bdb4 | 1514 | if (fun == NULL_TREE) |
732905bb | 1515 | return cxx_eval_internal_function (ctx, t, lval, |
1516 | non_constant_p, overflow_p); | |
6b71bdb4 | 1517 | |
09b42213 | 1518 | if (TREE_CODE (fun) != FUNCTION_DECL) |
1519 | { | |
1520 | /* Might be a constexpr function pointer. */ | |
f83e6885 | 1521 | fun = cxx_eval_constant_expression (ctx, fun, |
1227ba74 | 1522 | /*lval*/false, non_constant_p, |
b2a43197 | 1523 | overflow_p); |
09b42213 | 1524 | STRIP_NOPS (fun); |
1525 | if (TREE_CODE (fun) == ADDR_EXPR) | |
1526 | fun = TREE_OPERAND (fun, 0); | |
9a97d94a | 1527 | /* For TARGET_VTABLE_USES_DESCRIPTORS targets, there is no |
1528 | indirection, the called expression is a pointer into the | |
1529 | virtual table which should contain FDESC_EXPR. Extract the | |
1530 | FUNCTION_DECL from there. */ | |
1531 | else if (TARGET_VTABLE_USES_DESCRIPTORS | |
1532 | && TREE_CODE (fun) == POINTER_PLUS_EXPR | |
1533 | && TREE_CODE (TREE_OPERAND (fun, 0)) == ADDR_EXPR | |
1534 | && TREE_CODE (TREE_OPERAND (fun, 1)) == INTEGER_CST) | |
1535 | { | |
1536 | tree d = TREE_OPERAND (TREE_OPERAND (fun, 0), 0); | |
1537 | if (VAR_P (d) | |
1538 | && DECL_VTABLE_OR_VTT_P (d) | |
1539 | && TREE_CODE (TREE_TYPE (d)) == ARRAY_TYPE | |
1540 | && TREE_TYPE (TREE_TYPE (d)) == vtable_entry_type | |
1541 | && DECL_INITIAL (d) | |
1542 | && TREE_CODE (DECL_INITIAL (d)) == CONSTRUCTOR) | |
1543 | { | |
1544 | tree i = int_const_binop (TRUNC_DIV_EXPR, TREE_OPERAND (fun, 1), | |
1545 | TYPE_SIZE_UNIT (vtable_entry_type)); | |
1546 | HOST_WIDE_INT idx = find_array_ctor_elt (DECL_INITIAL (d), i); | |
1547 | if (idx >= 0) | |
1548 | { | |
1549 | tree fdesc | |
1550 | = (*CONSTRUCTOR_ELTS (DECL_INITIAL (d)))[idx].value; | |
1551 | if (TREE_CODE (fdesc) == FDESC_EXPR | |
1552 | && integer_zerop (TREE_OPERAND (fdesc, 1))) | |
1553 | fun = TREE_OPERAND (fdesc, 0); | |
1554 | } | |
1555 | } | |
1556 | } | |
09b42213 | 1557 | } |
1558 | if (TREE_CODE (fun) != FUNCTION_DECL) | |
1559 | { | |
f83e6885 | 1560 | if (!ctx->quiet && !*non_constant_p) |
5967b28b | 1561 | error_at (loc, "expression %qE does not designate a %<constexpr%> " |
09b42213 | 1562 | "function", fun); |
1563 | *non_constant_p = true; | |
1564 | return t; | |
1565 | } | |
1566 | if (DECL_CLONED_FUNCTION_P (fun)) | |
1567 | fun = DECL_CLONED_FUNCTION (fun); | |
6b71bdb4 | 1568 | |
1569 | if (is_ubsan_builtin_p (fun)) | |
1570 | return void_node; | |
1571 | ||
a0e9bfbb | 1572 | if (fndecl_built_in_p (fun)) |
f1c6af10 | 1573 | return cxx_eval_builtin_function_call (ctx, t, fun, |
1227ba74 | 1574 | lval, non_constant_p, overflow_p); |
09b42213 | 1575 | if (!DECL_DECLARED_CONSTEXPR_P (fun)) |
1576 | { | |
f83e6885 | 1577 | if (!ctx->quiet) |
09b42213 | 1578 | { |
1dcd84cf | 1579 | if (!lambda_static_thunk_p (fun)) |
5967b28b | 1580 | error_at (loc, "call to non-%<constexpr%> function %qD", fun); |
09b42213 | 1581 | explain_invalid_constexpr_fn (fun); |
1582 | } | |
1583 | *non_constant_p = true; | |
1584 | return t; | |
1585 | } | |
1586 | ||
9ebe2ea3 | 1587 | constexpr_ctx new_ctx = *ctx; |
1588 | if (DECL_CONSTRUCTOR_P (fun) && !ctx->object | |
1589 | && TREE_CODE (t) == AGGR_INIT_EXPR) | |
1590 | { | |
1591 | /* We want to have an initialization target for an AGGR_INIT_EXPR. | |
1592 | If we don't already have one in CTX, use the AGGR_INIT_EXPR_SLOT. */ | |
1593 | new_ctx.object = AGGR_INIT_EXPR_SLOT (t); | |
1594 | tree ctor = new_ctx.ctor = build_constructor (DECL_CONTEXT (fun), NULL); | |
165d0d5b | 1595 | CONSTRUCTOR_NO_CLEARING (ctor) = true; |
9ebe2ea3 | 1596 | ctx->values->put (new_ctx.object, ctor); |
1597 | ctx = &new_ctx; | |
1598 | } | |
1599 | ||
09b42213 | 1600 | /* Shortcut trivial constructor/op=. */ |
1601 | if (trivial_fn_p (fun)) | |
1602 | { | |
9ebe2ea3 | 1603 | tree init = NULL_TREE; |
09b42213 | 1604 | if (call_expr_nargs (t) == 2) |
9ebe2ea3 | 1605 | init = convert_from_reference (get_nth_callarg (t, 1)); |
09b42213 | 1606 | else if (TREE_CODE (t) == AGGR_INIT_EXPR |
1607 | && AGGR_INIT_ZERO_FIRST (t)) | |
9ebe2ea3 | 1608 | init = build_zero_init (DECL_CONTEXT (fun), NULL_TREE, false); |
1609 | if (init) | |
1610 | { | |
1611 | tree op = get_nth_callarg (t, 0); | |
1612 | if (is_dummy_object (op)) | |
1613 | op = ctx->object; | |
1614 | else | |
1615 | op = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (op)), op); | |
1616 | tree set = build2 (MODIFY_EXPR, TREE_TYPE (op), op, init); | |
0ce12360 | 1617 | new_ctx.call = &new_call; |
1618 | return cxx_eval_constant_expression (&new_ctx, set, lval, | |
9ebe2ea3 | 1619 | non_constant_p, overflow_p); |
1620 | } | |
09b42213 | 1621 | } |
1622 | ||
8afcf831 | 1623 | /* We can't defer instantiating the function any longer. */ |
1624 | if (!DECL_INITIAL (fun) | |
1625 | && DECL_TEMPLOID_INSTANTIATION (fun)) | |
1626 | { | |
31db86df | 1627 | location_t save_loc = input_location; |
1628 | input_location = loc; | |
8afcf831 | 1629 | ++function_depth; |
1630 | instantiate_decl (fun, /*defer_ok*/false, /*expl_inst*/false); | |
1631 | --function_depth; | |
31db86df | 1632 | input_location = save_loc; |
8afcf831 | 1633 | } |
1634 | ||
09b42213 | 1635 | /* If in direct recursive call, optimize definition search. */ |
0ce12360 | 1636 | if (ctx && ctx->call && ctx->call->fundef && ctx->call->fundef->decl == fun) |
cf72f34d | 1637 | new_call.fundef = ctx->call->fundef; |
09b42213 | 1638 | else |
1639 | { | |
1640 | new_call.fundef = retrieve_constexpr_fundef (fun); | |
d2a9b1c1 | 1641 | if (new_call.fundef == NULL || new_call.fundef->body == NULL |
1642 | || fun == current_function_decl) | |
09b42213 | 1643 | { |
f83e6885 | 1644 | if (!ctx->quiet) |
09b42213 | 1645 | { |
d2a9b1c1 | 1646 | /* We need to check for current_function_decl here in case we're |
1647 | being called during cp_fold_function, because at that point | |
1648 | DECL_INITIAL is set properly and we have a fundef but we | |
1649 | haven't lowered invisirefs yet (c++/70344). */ | |
1650 | if (DECL_INITIAL (fun) == error_mark_node | |
1651 | || fun == current_function_decl) | |
a0efa758 | 1652 | error_at (loc, "%qD called in a constant expression before its " |
1653 | "definition is complete", fun); | |
1654 | else if (DECL_INITIAL (fun)) | |
09b42213 | 1655 | { |
33603066 | 1656 | /* The definition of fun was somehow unsuitable. But pretend |
1657 | that lambda static thunks don't exist. */ | |
1658 | if (!lambda_static_thunk_p (fun)) | |
1659 | error_at (loc, "%qD called in a constant expression", fun); | |
09b42213 | 1660 | explain_invalid_constexpr_fn (fun); |
1661 | } | |
1662 | else | |
1663 | error_at (loc, "%qD used before its definition", fun); | |
1664 | } | |
1665 | *non_constant_p = true; | |
1666 | return t; | |
1667 | } | |
1668 | } | |
9c96033c | 1669 | |
c8f6aeb1 | 1670 | bool non_constant_args = false; |
cf72f34d | 1671 | cxx_bind_parameters_in_call (ctx, t, &new_call, |
c8f6aeb1 | 1672 | non_constant_p, overflow_p, &non_constant_args); |
09b42213 | 1673 | if (*non_constant_p) |
1674 | return t; | |
1675 | ||
1676 | depth_ok = push_cx_call_context (t); | |
1677 | ||
c8f6aeb1 | 1678 | tree result = NULL_TREE; |
09b42213 | 1679 | |
c8f6aeb1 | 1680 | constexpr_call *entry = NULL; |
167a09fb | 1681 | if (depth_ok && !non_constant_args && ctx->strict) |
09b42213 | 1682 | { |
919873c7 | 1683 | new_call.hash = constexpr_fundef_hasher::hash (new_call.fundef); |
1684 | new_call.hash | |
1685 | = iterative_hash_template_arg (new_call.bindings, new_call.hash); | |
1686 | new_call.hash | |
1562c831 | 1687 | = iterative_hash_object (ctx->manifestly_const_eval, new_call.hash); |
c8f6aeb1 | 1688 | |
1689 | /* If we have seen this call before, we are done. */ | |
1690 | maybe_initialize_constexpr_call_table (); | |
1691 | constexpr_call **slot | |
1692 | = constexpr_call_table->find_slot (&new_call, INSERT); | |
1693 | entry = *slot; | |
1694 | if (entry == NULL) | |
1695 | { | |
1696 | /* We need to keep a pointer to the entry, not just the slot, as the | |
1697 | slot can move in the call to cxx_eval_builtin_function_call. */ | |
1698 | *slot = entry = ggc_alloc<constexpr_call> (); | |
1699 | *entry = new_call; | |
1700 | } | |
2ba934c7 | 1701 | /* Calls that are in progress have their result set to NULL, |
c8f6aeb1 | 1702 | so that we can detect circular dependencies. */ |
1703 | else if (entry->result == NULL) | |
1704 | { | |
1705 | if (!ctx->quiet) | |
1706 | error ("call has circular dependency"); | |
1707 | *non_constant_p = true; | |
1708 | entry->result = result = error_mark_node; | |
1709 | } | |
1710 | else | |
1711 | result = entry->result; | |
09b42213 | 1712 | } |
1713 | ||
1714 | if (!depth_ok) | |
1715 | { | |
f83e6885 | 1716 | if (!ctx->quiet) |
5967b28b | 1717 | error ("%<constexpr%> evaluation depth exceeds maximum of %d (use " |
f91d3a9d | 1718 | "%<-fconstexpr-depth=%> to increase the maximum)", |
09b42213 | 1719 | max_constexpr_depth); |
1720 | *non_constant_p = true; | |
c8f6aeb1 | 1721 | result = error_mark_node; |
09b42213 | 1722 | } |
1723 | else | |
1724 | { | |
ab099088 | 1725 | if (result && result != error_mark_node) |
1726 | /* OK */; | |
1727 | else if (!DECL_SAVED_TREE (fun)) | |
1728 | { | |
1729 | /* When at_eof >= 2, cgraph has started throwing away | |
1730 | DECL_SAVED_TREE, so fail quietly. FIXME we get here because of | |
1731 | late code generation for VEC_INIT_EXPR, which needs to be | |
1732 | completely reconsidered. */ | |
1733 | gcc_assert (at_eof >= 2 && ctx->quiet); | |
1734 | *non_constant_p = true; | |
1735 | } | |
1736 | else | |
cf72f34d | 1737 | { |
4f7ebe46 | 1738 | tree body, parms, res; |
88a59139 | 1739 | |
4f7ebe46 | 1740 | /* Reuse or create a new unshared copy of this function's body. */ |
a050099a | 1741 | tree copy = get_fundef_copy (fun); |
1742 | body = TREE_PURPOSE (copy); | |
1743 | parms = TREE_VALUE (copy); | |
1744 | res = TREE_TYPE (copy); | |
88a59139 | 1745 | |
1746 | /* Associate the bindings with the remapped parms. */ | |
1747 | tree bound = new_call.bindings; | |
1748 | tree remapped = parms; | |
1749 | while (bound) | |
9c96033c | 1750 | { |
88a59139 | 1751 | tree oparm = TREE_PURPOSE (bound); |
1752 | tree arg = TREE_VALUE (bound); | |
1753 | gcc_assert (DECL_NAME (remapped) == DECL_NAME (oparm)); | |
5898f0d7 | 1754 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 1755 | arg = unshare_constructor (arg); |
88a59139 | 1756 | ctx->values->put (remapped, arg); |
1757 | bound = TREE_CHAIN (bound); | |
1758 | remapped = DECL_CHAIN (remapped); | |
9c96033c | 1759 | } |
88a59139 | 1760 | /* Add the RESULT_DECL to the values map, too. */ |
1761 | tree slot = NULL_TREE; | |
1762 | if (DECL_BY_REFERENCE (res)) | |
9c96033c | 1763 | { |
88a59139 | 1764 | slot = AGGR_INIT_EXPR_SLOT (t); |
1765 | tree addr = build_address (slot); | |
1766 | addr = build_nop (TREE_TYPE (res), addr); | |
1767 | ctx->values->put (res, addr); | |
1768 | ctx->values->put (slot, NULL_TREE); | |
1769 | } | |
1770 | else | |
1771 | ctx->values->put (res, NULL_TREE); | |
9c96033c | 1772 | |
4f7ebe46 | 1773 | /* Track the callee's evaluated SAVE_EXPRs so that we can forget |
1774 | their values after the call. */ | |
1775 | constexpr_ctx ctx_with_save_exprs = *ctx; | |
1776 | hash_set<tree> save_exprs; | |
1777 | ctx_with_save_exprs.save_exprs = &save_exprs; | |
43b7271d | 1778 | ctx_with_save_exprs.call = &new_call; |
4f7ebe46 | 1779 | |
88a59139 | 1780 | tree jump_target = NULL_TREE; |
4f7ebe46 | 1781 | cxx_eval_constant_expression (&ctx_with_save_exprs, body, |
88a59139 | 1782 | lval, non_constant_p, overflow_p, |
1783 | &jump_target); | |
9c96033c | 1784 | |
88a59139 | 1785 | if (DECL_CONSTRUCTOR_P (fun)) |
1786 | /* This can be null for a subobject constructor call, in | |
1787 | which case what we care about is the initialization | |
1788 | side-effects rather than the value. We could get at the | |
1789 | value by evaluating *this, but we don't bother; there's | |
1790 | no need to put such a call in the hash table. */ | |
1791 | result = lval ? ctx->object : ctx->ctor; | |
1792 | else if (VOID_TYPE_P (TREE_TYPE (res))) | |
1793 | result = void_node; | |
1794 | else | |
1795 | { | |
1796 | result = *ctx->values->get (slot ? slot : res); | |
1797 | if (result == NULL_TREE && !*non_constant_p) | |
9c96033c | 1798 | { |
88a59139 | 1799 | if (!ctx->quiet) |
5967b28b | 1800 | error ("%<constexpr%> call flows off the end " |
88a59139 | 1801 | "of the function"); |
1802 | *non_constant_p = true; | |
9c96033c | 1803 | } |
9c96033c | 1804 | } |
88a59139 | 1805 | |
4f7ebe46 | 1806 | /* Forget the saved values of the callee's SAVE_EXPRs. */ |
1807 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
1808 | iter != save_exprs.end(); ++iter) | |
1809 | ctx_with_save_exprs.values->remove (*iter); | |
1810 | ||
88a59139 | 1811 | /* Remove the parms/result from the values map. Is it worth |
1812 | bothering to do this when the map itself is only live for | |
1813 | one constexpr evaluation? If so, maybe also clear out | |
1814 | other vars from call, maybe in BIND_EXPR handling? */ | |
1815 | ctx->values->remove (res); | |
1816 | if (slot) | |
1817 | ctx->values->remove (slot); | |
1818 | for (tree parm = parms; parm; parm = TREE_CHAIN (parm)) | |
1819 | ctx->values->remove (parm); | |
4f7ebe46 | 1820 | |
1821 | /* Make the unshared function copy we used available for re-use. */ | |
1822 | save_fundef_copy (fun, copy); | |
cf72f34d | 1823 | } |
9c96033c | 1824 | |
09b42213 | 1825 | if (result == error_mark_node) |
1826 | *non_constant_p = true; | |
c3f376bf | 1827 | if (*non_constant_p || *overflow_p) |
c8f6aeb1 | 1828 | result = error_mark_node; |
88a59139 | 1829 | else if (!result) |
9c96033c | 1830 | result = void_node; |
c8f6aeb1 | 1831 | if (entry) |
1832 | entry->result = result; | |
09b42213 | 1833 | } |
1834 | ||
c6d97004 | 1835 | /* The result of a constexpr function must be completely initialized. */ |
1836 | if (TREE_CODE (result) == CONSTRUCTOR) | |
79cdb4f5 | 1837 | clear_no_implicit_zero (result); |
c6d97004 | 1838 | |
09b42213 | 1839 | pop_cx_call_context (); |
e283bb4f | 1840 | return unshare_constructor (result); |
09b42213 | 1841 | } |
1842 | ||
1843 | /* FIXME speed this up, it's taking 16% of compile time on sieve testcase. */ | |
1844 | ||
1845 | bool | |
1846 | reduced_constant_expression_p (tree t) | |
1847 | { | |
a34934c2 | 1848 | if (t == NULL_TREE) |
1849 | return false; | |
1850 | ||
09b42213 | 1851 | switch (TREE_CODE (t)) |
1852 | { | |
1853 | case PTRMEM_CST: | |
1854 | /* Even if we can't lower this yet, it's constant. */ | |
1855 | return true; | |
1856 | ||
1857 | case CONSTRUCTOR: | |
1858 | /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */ | |
56da7fe6 | 1859 | tree idx, val, field; unsigned HOST_WIDE_INT i; |
165d0d5b | 1860 | if (CONSTRUCTOR_NO_CLEARING (t)) |
c4210852 | 1861 | { |
1862 | if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE) | |
1863 | /* An initialized vector would have a VECTOR_CST. */ | |
1864 | return false; | |
1865 | else | |
1866 | field = next_initializable_field (TYPE_FIELDS (TREE_TYPE (t))); | |
1867 | } | |
56da7fe6 | 1868 | else |
1869 | field = NULL_TREE; | |
1870 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t), i, idx, val) | |
ce4ffd9e | 1871 | { |
a34934c2 | 1872 | /* If VAL is null, we're in the middle of initializing this |
1873 | element. */ | |
56da7fe6 | 1874 | if (!reduced_constant_expression_p (val)) |
ce4ffd9e | 1875 | return false; |
56da7fe6 | 1876 | if (field) |
1877 | { | |
1878 | if (idx != field) | |
1879 | return false; | |
1880 | field = next_initializable_field (DECL_CHAIN (field)); | |
1881 | } | |
ce4ffd9e | 1882 | } |
56da7fe6 | 1883 | if (field) |
1884 | return false; | |
165d0d5b | 1885 | else if (CONSTRUCTOR_NO_CLEARING (t)) |
56da7fe6 | 1886 | /* All the fields are initialized. */ |
165d0d5b | 1887 | CONSTRUCTOR_NO_CLEARING (t) = false; |
09b42213 | 1888 | return true; |
1889 | ||
1890 | default: | |
1891 | /* FIXME are we calling this too much? */ | |
1892 | return initializer_constant_valid_p (t, TREE_TYPE (t)) != NULL_TREE; | |
1893 | } | |
1894 | } | |
1895 | ||
1896 | /* Some expressions may have constant operands but are not constant | |
941fafa5 | 1897 | themselves, such as 1/0. Call this function to check for that |
1898 | condition. | |
09b42213 | 1899 | |
1900 | We only call this in places that require an arithmetic constant, not in | |
1901 | places where we might have a non-constant expression that can be a | |
1902 | component of a constant expression, such as the address of a constexpr | |
1903 | variable that might be dereferenced later. */ | |
1904 | ||
1905 | static bool | |
1906 | verify_constant (tree t, bool allow_non_constant, bool *non_constant_p, | |
1907 | bool *overflow_p) | |
1908 | { | |
1909 | if (!*non_constant_p && !reduced_constant_expression_p (t)) | |
1910 | { | |
1911 | if (!allow_non_constant) | |
1912 | error ("%q+E is not a constant expression", t); | |
1913 | *non_constant_p = true; | |
1914 | } | |
1915 | if (TREE_OVERFLOW_P (t)) | |
1916 | { | |
1917 | if (!allow_non_constant) | |
1918 | { | |
1919 | permerror (input_location, "overflow in constant expression"); | |
1920 | /* If we're being permissive (and are in an enforcing | |
1921 | context), ignore the overflow. */ | |
1922 | if (flag_permissive) | |
1923 | return *non_constant_p; | |
1924 | } | |
1925 | *overflow_p = true; | |
1926 | } | |
1927 | return *non_constant_p; | |
1928 | } | |
1929 | ||
2b035ffe | 1930 | /* Check whether the shift operation with code CODE and type TYPE on LHS |
1931 | and RHS is undefined. If it is, give an error with an explanation, | |
1932 | and return true; return false otherwise. */ | |
1933 | ||
1934 | static bool | |
1935 | cxx_eval_check_shift_p (location_t loc, const constexpr_ctx *ctx, | |
1936 | enum tree_code code, tree type, tree lhs, tree rhs) | |
1937 | { | |
1938 | if ((code != LSHIFT_EXPR && code != RSHIFT_EXPR) | |
1939 | || TREE_CODE (lhs) != INTEGER_CST | |
1940 | || TREE_CODE (rhs) != INTEGER_CST) | |
1941 | return false; | |
1942 | ||
1943 | tree lhstype = TREE_TYPE (lhs); | |
1944 | unsigned HOST_WIDE_INT uprec = TYPE_PRECISION (TREE_TYPE (lhs)); | |
1945 | ||
1946 | /* [expr.shift] The behavior is undefined if the right operand | |
1947 | is negative, or greater than or equal to the length in bits | |
1948 | of the promoted left operand. */ | |
1949 | if (tree_int_cst_sgn (rhs) == -1) | |
1950 | { | |
1951 | if (!ctx->quiet) | |
91d87e22 | 1952 | permerror (loc, "right operand of shift expression %q+E is negative", |
1953 | build2_loc (loc, code, type, lhs, rhs)); | |
1954 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1955 | } |
1956 | if (compare_tree_int (rhs, uprec) >= 0) | |
1957 | { | |
1958 | if (!ctx->quiet) | |
91d87e22 | 1959 | permerror (loc, "right operand of shift expression %q+E is >= than " |
1960 | "the precision of the left operand", | |
1961 | build2_loc (loc, code, type, lhs, rhs)); | |
1962 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1963 | } |
1964 | ||
1965 | /* The value of E1 << E2 is E1 left-shifted E2 bit positions; [...] | |
1966 | if E1 has a signed type and non-negative value, and E1x2^E2 is | |
1967 | representable in the corresponding unsigned type of the result type, | |
1968 | then that value, converted to the result type, is the resulting value; | |
1170ee75 | 1969 | otherwise, the behavior is undefined. |
1970 | For C++2a: | |
1971 | The value of E1 << E2 is the unique value congruent to E1 x 2^E2 modulo | |
1972 | 2^N, where N is the range exponent of the type of the result. */ | |
1973 | if (code == LSHIFT_EXPR | |
1974 | && !TYPE_UNSIGNED (lhstype) | |
1975 | && cxx_dialect >= cxx11 | |
1976 | && cxx_dialect < cxx2a) | |
2b035ffe | 1977 | { |
1978 | if (tree_int_cst_sgn (lhs) == -1) | |
1979 | { | |
1980 | if (!ctx->quiet) | |
91d87e22 | 1981 | permerror (loc, |
1982 | "left operand of shift expression %q+E is negative", | |
1983 | build2_loc (loc, code, type, lhs, rhs)); | |
1984 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 1985 | } |
1986 | /* For signed x << y the following: | |
1987 | (unsigned) x >> ((prec (lhs) - 1) - y) | |
1988 | if > 1, is undefined. The right-hand side of this formula | |
1989 | is the highest bit of the LHS that can be set (starting from 0), | |
1990 | so that the shift doesn't overflow. We then right-shift the LHS | |
1991 | to see whether any other bit is set making the original shift | |
1992 | undefined -- the result is not representable in the corresponding | |
1993 | unsigned type. */ | |
1994 | tree t = build_int_cst (unsigned_type_node, uprec - 1); | |
1995 | t = fold_build2 (MINUS_EXPR, unsigned_type_node, t, rhs); | |
1996 | tree ulhs = fold_convert (unsigned_type_for (lhstype), lhs); | |
1997 | t = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ulhs), ulhs, t); | |
1998 | if (tree_int_cst_lt (integer_one_node, t)) | |
1999 | { | |
2000 | if (!ctx->quiet) | |
91d87e22 | 2001 | permerror (loc, "shift expression %q+E overflows", |
2002 | build2_loc (loc, code, type, lhs, rhs)); | |
2003 | return (!flag_permissive || ctx->quiet); | |
2b035ffe | 2004 | } |
2005 | } | |
2006 | return false; | |
2007 | } | |
2008 | ||
09b42213 | 2009 | /* Subroutine of cxx_eval_constant_expression. |
2010 | Attempt to reduce the unary expression tree T to a compile time value. | |
2011 | If successful, return the value. Otherwise issue a diagnostic | |
2012 | and return error_mark_node. */ | |
2013 | ||
2014 | static tree | |
cf72f34d | 2015 | cxx_eval_unary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 2016 | bool /*lval*/, |
09b42213 | 2017 | bool *non_constant_p, bool *overflow_p) |
2018 | { | |
2019 | tree r; | |
2020 | tree orig_arg = TREE_OPERAND (t, 0); | |
c8f6aeb1 | 2021 | tree arg = cxx_eval_constant_expression (ctx, orig_arg, /*lval*/false, |
2022 | non_constant_p, overflow_p); | |
09b42213 | 2023 | VERIFY_CONSTANT (arg); |
93add516 | 2024 | location_t loc = EXPR_LOCATION (t); |
2025 | enum tree_code code = TREE_CODE (t); | |
2026 | tree type = TREE_TYPE (t); | |
2027 | r = fold_unary_loc (loc, code, type, arg); | |
2028 | if (r == NULL_TREE) | |
2029 | { | |
2030 | if (arg == orig_arg) | |
2031 | r = t; | |
2032 | else | |
2033 | r = build1_loc (loc, code, type, arg); | |
2034 | } | |
09b42213 | 2035 | VERIFY_CONSTANT (r); |
2036 | return r; | |
2037 | } | |
2038 | ||
46fad8d5 | 2039 | /* Helper function for cxx_eval_binary_expression. Try to optimize |
2040 | original POINTER_PLUS_EXPR T, LHS p+ RHS, return NULL_TREE if the | |
2041 | generic folding should be used. */ | |
2042 | ||
2043 | static tree | |
2044 | cxx_fold_pointer_plus_expression (const constexpr_ctx *ctx, tree t, | |
2045 | tree lhs, tree rhs, bool *non_constant_p, | |
2046 | bool *overflow_p) | |
2047 | { | |
2048 | STRIP_NOPS (lhs); | |
2049 | if (TREE_CODE (lhs) != ADDR_EXPR) | |
2050 | return NULL_TREE; | |
2051 | ||
2052 | lhs = TREE_OPERAND (lhs, 0); | |
2053 | ||
2054 | /* &A[i] p+ j => &A[i + j] */ | |
2055 | if (TREE_CODE (lhs) == ARRAY_REF | |
2056 | && TREE_CODE (TREE_OPERAND (lhs, 1)) == INTEGER_CST | |
2057 | && TREE_CODE (rhs) == INTEGER_CST | |
2058 | && TYPE_SIZE_UNIT (TREE_TYPE (lhs)) | |
2059 | && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (lhs))) == INTEGER_CST) | |
2060 | { | |
2061 | tree orig_type = TREE_TYPE (t); | |
2062 | location_t loc = EXPR_LOCATION (t); | |
2063 | tree type = TREE_TYPE (lhs); | |
2064 | ||
2065 | t = fold_convert_loc (loc, ssizetype, TREE_OPERAND (lhs, 1)); | |
2066 | tree nelts = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (lhs, 0))); | |
2067 | nelts = cxx_eval_constant_expression (ctx, nelts, false, non_constant_p, | |
2068 | overflow_p); | |
2069 | if (*non_constant_p) | |
2070 | return NULL_TREE; | |
2071 | /* Don't fold an out-of-bound access. */ | |
2072 | if (!tree_int_cst_le (t, nelts)) | |
2073 | return NULL_TREE; | |
2074 | rhs = cp_fold_convert (ssizetype, rhs); | |
2075 | /* Don't fold if rhs can't be divided exactly by TYPE_SIZE_UNIT. | |
2076 | constexpr int A[1]; ... (char *)&A[0] + 1 */ | |
2077 | if (!integer_zerop (fold_build2_loc (loc, TRUNC_MOD_EXPR, sizetype, | |
2078 | rhs, TYPE_SIZE_UNIT (type)))) | |
2079 | return NULL_TREE; | |
2080 | /* Make sure to treat the second operand of POINTER_PLUS_EXPR | |
2081 | as signed. */ | |
2082 | rhs = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, rhs, | |
2083 | TYPE_SIZE_UNIT (type)); | |
2084 | t = size_binop_loc (loc, PLUS_EXPR, rhs, t); | |
2085 | t = build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (lhs, 0), | |
2086 | t, NULL_TREE, NULL_TREE); | |
2087 | t = cp_build_addr_expr (t, tf_warning_or_error); | |
2088 | t = cp_fold_convert (orig_type, t); | |
2089 | return cxx_eval_constant_expression (ctx, t, /*lval*/false, | |
2090 | non_constant_p, overflow_p); | |
2091 | } | |
2092 | ||
2093 | return NULL_TREE; | |
2094 | } | |
2095 | ||
09b42213 | 2096 | /* Subroutine of cxx_eval_constant_expression. |
2097 | Like cxx_eval_unary_expression, except for binary expressions. */ | |
2098 | ||
2099 | static tree | |
cf72f34d | 2100 | cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, |
c8f6aeb1 | 2101 | bool /*lval*/, |
09b42213 | 2102 | bool *non_constant_p, bool *overflow_p) |
2103 | { | |
f7ef5392 | 2104 | tree r = NULL_TREE; |
09b42213 | 2105 | tree orig_lhs = TREE_OPERAND (t, 0); |
2106 | tree orig_rhs = TREE_OPERAND (t, 1); | |
2107 | tree lhs, rhs; | |
c8f6aeb1 | 2108 | lhs = cxx_eval_constant_expression (ctx, orig_lhs, /*lval*/false, |
b2a43197 | 2109 | non_constant_p, overflow_p); |
6d6737d9 | 2110 | /* Don't VERIFY_CONSTANT here, it's unnecessary and will break pointer |
2111 | subtraction. */ | |
2112 | if (*non_constant_p) | |
2113 | return t; | |
c8f6aeb1 | 2114 | rhs = cxx_eval_constant_expression (ctx, orig_rhs, /*lval*/false, |
b2a43197 | 2115 | non_constant_p, overflow_p); |
6d6737d9 | 2116 | if (*non_constant_p) |
2117 | return t; | |
93add516 | 2118 | |
2119 | location_t loc = EXPR_LOCATION (t); | |
2120 | enum tree_code code = TREE_CODE (t); | |
2121 | tree type = TREE_TYPE (t); | |
f7ef5392 | 2122 | |
2123 | if (code == EQ_EXPR || code == NE_EXPR) | |
2124 | { | |
2125 | bool is_code_eq = (code == EQ_EXPR); | |
2126 | ||
2127 | if (TREE_CODE (lhs) == PTRMEM_CST | |
2128 | && TREE_CODE (rhs) == PTRMEM_CST) | |
e9f29fe5 | 2129 | { |
2130 | tree lmem = PTRMEM_CST_MEMBER (lhs); | |
2131 | tree rmem = PTRMEM_CST_MEMBER (rhs); | |
2132 | bool eq; | |
2133 | if (TREE_CODE (lmem) == TREE_CODE (rmem) | |
2134 | && TREE_CODE (lmem) == FIELD_DECL | |
2135 | && TREE_CODE (DECL_CONTEXT (lmem)) == UNION_TYPE | |
2136 | && same_type_p (DECL_CONTEXT (lmem), | |
2137 | DECL_CONTEXT (rmem))) | |
2138 | /* If both refer to (possibly different) members of the same union | |
2139 | (12.3), they compare equal. */ | |
2140 | eq = true; | |
2141 | else | |
2142 | eq = cp_tree_equal (lhs, rhs); | |
2143 | r = constant_boolean_node (eq == is_code_eq, type); | |
2144 | } | |
f7ef5392 | 2145 | else if ((TREE_CODE (lhs) == PTRMEM_CST |
2146 | || TREE_CODE (rhs) == PTRMEM_CST) | |
2147 | && (null_member_pointer_value_p (lhs) | |
2148 | || null_member_pointer_value_p (rhs))) | |
2149 | r = constant_boolean_node (!is_code_eq, type); | |
f31f4e9c | 2150 | else if (TREE_CODE (lhs) == PTRMEM_CST) |
2151 | lhs = cplus_expand_constant (lhs); | |
2152 | else if (TREE_CODE (rhs) == PTRMEM_CST) | |
2153 | rhs = cplus_expand_constant (rhs); | |
f7ef5392 | 2154 | } |
cb768824 | 2155 | if (code == POINTER_PLUS_EXPR && !*non_constant_p |
2156 | && integer_zerop (lhs) && !integer_zerop (rhs)) | |
2157 | { | |
2158 | if (!ctx->quiet) | |
2159 | error ("arithmetic involving a null pointer in %qE", lhs); | |
2b1749c4 | 2160 | *non_constant_p = true; |
cb768824 | 2161 | return t; |
2162 | } | |
46fad8d5 | 2163 | else if (code == POINTER_PLUS_EXPR) |
2164 | r = cxx_fold_pointer_plus_expression (ctx, t, lhs, rhs, non_constant_p, | |
2165 | overflow_p); | |
f7ef5392 | 2166 | |
2167 | if (r == NULL_TREE) | |
2168 | r = fold_binary_loc (loc, code, type, lhs, rhs); | |
2169 | ||
93add516 | 2170 | if (r == NULL_TREE) |
2171 | { | |
2172 | if (lhs == orig_lhs && rhs == orig_rhs) | |
2173 | r = t; | |
2174 | else | |
2175 | r = build2_loc (loc, code, type, lhs, rhs); | |
2176 | } | |
2b035ffe | 2177 | else if (cxx_eval_check_shift_p (loc, ctx, code, type, lhs, rhs)) |
2178 | *non_constant_p = true; | |
6d6737d9 | 2179 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
2180 | a local array in a constexpr function. */ | |
d03fa520 | 2181 | bool ptr = INDIRECT_TYPE_P (TREE_TYPE (lhs)); |
35f2c28f | 2182 | if (!ptr) |
aae7465c | 2183 | VERIFY_CONSTANT (r); |
09b42213 | 2184 | return r; |
2185 | } | |
2186 | ||
2187 | /* Subroutine of cxx_eval_constant_expression. | |
2188 | Attempt to evaluate condition expressions. Dead branches are not | |
2189 | looked into. */ | |
2190 | ||
2191 | static tree | |
cf72f34d | 2192 | cxx_eval_conditional_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2193 | bool lval, |
00f21715 | 2194 | bool *non_constant_p, bool *overflow_p, |
2195 | tree *jump_target) | |
09b42213 | 2196 | { |
cf72f34d | 2197 | tree val = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
c8f6aeb1 | 2198 | /*lval*/false, |
b2a43197 | 2199 | non_constant_p, overflow_p); |
09b42213 | 2200 | VERIFY_CONSTANT (val); |
2201 | /* Don't VERIFY_CONSTANT the other operands. */ | |
2202 | if (integer_zerop (val)) | |
cf72f34d | 2203 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), |
1227ba74 | 2204 | lval, |
00f21715 | 2205 | non_constant_p, overflow_p, |
2206 | jump_target); | |
cf72f34d | 2207 | return cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2208 | lval, |
00f21715 | 2209 | non_constant_p, overflow_p, |
2210 | jump_target); | |
09b42213 | 2211 | } |
2212 | ||
31595caf | 2213 | /* Subroutine of cxx_eval_constant_expression. |
2214 | Attempt to evaluate vector condition expressions. Unlike | |
2215 | cxx_eval_conditional_expression, VEC_COND_EXPR acts like a normal | |
2216 | ternary arithmetics operation, where all 3 arguments have to be | |
2217 | evaluated as constants and then folding computes the result from | |
2218 | them. */ | |
2219 | ||
2220 | static tree | |
2221 | cxx_eval_vector_conditional_expression (const constexpr_ctx *ctx, tree t, | |
2222 | bool *non_constant_p, bool *overflow_p) | |
2223 | { | |
2224 | tree arg1 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
2225 | /*lval*/false, | |
2226 | non_constant_p, overflow_p); | |
2227 | VERIFY_CONSTANT (arg1); | |
2228 | tree arg2 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
2229 | /*lval*/false, | |
2230 | non_constant_p, overflow_p); | |
2231 | VERIFY_CONSTANT (arg2); | |
2232 | tree arg3 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
2233 | /*lval*/false, | |
2234 | non_constant_p, overflow_p); | |
2235 | VERIFY_CONSTANT (arg3); | |
2236 | location_t loc = EXPR_LOCATION (t); | |
2237 | tree type = TREE_TYPE (t); | |
2238 | tree r = fold_ternary_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2239 | if (r == NULL_TREE) | |
2240 | { | |
2241 | if (arg1 == TREE_OPERAND (t, 0) | |
2242 | && arg2 == TREE_OPERAND (t, 1) | |
2243 | && arg3 == TREE_OPERAND (t, 2)) | |
2244 | r = t; | |
2245 | else | |
2246 | r = build3_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); | |
2247 | } | |
2248 | VERIFY_CONSTANT (r); | |
2249 | return r; | |
2250 | } | |
2251 | ||
7963b19d | 2252 | /* Returns less than, equal to, or greater than zero if KEY is found to be |
2253 | less than, to match, or to be greater than the constructor_elt's INDEX. */ | |
2254 | ||
2255 | static int | |
2256 | array_index_cmp (tree key, tree index) | |
2257 | { | |
2258 | gcc_assert (TREE_CODE (key) == INTEGER_CST); | |
2259 | ||
2260 | switch (TREE_CODE (index)) | |
2261 | { | |
2262 | case INTEGER_CST: | |
2263 | return tree_int_cst_compare (key, index); | |
2264 | case RANGE_EXPR: | |
2265 | { | |
2266 | tree lo = TREE_OPERAND (index, 0); | |
2267 | tree hi = TREE_OPERAND (index, 1); | |
2268 | if (tree_int_cst_lt (key, lo)) | |
2269 | return -1; | |
2270 | else if (tree_int_cst_lt (hi, key)) | |
2271 | return 1; | |
2272 | else | |
2273 | return 0; | |
2274 | } | |
2275 | default: | |
2276 | gcc_unreachable (); | |
2277 | } | |
2278 | } | |
2279 | ||
2280 | /* Returns the index of the constructor_elt of ARY which matches DINDEX, or -1 | |
2281 | if none. If INSERT is true, insert a matching element rather than fail. */ | |
2282 | ||
2283 | static HOST_WIDE_INT | |
9a97d94a | 2284 | find_array_ctor_elt (tree ary, tree dindex, bool insert) |
7963b19d | 2285 | { |
2286 | if (tree_int_cst_sgn (dindex) < 0) | |
2287 | return -1; | |
2288 | ||
2289 | unsigned HOST_WIDE_INT i = tree_to_uhwi (dindex); | |
2290 | vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (ary); | |
2291 | unsigned HOST_WIDE_INT len = vec_safe_length (elts); | |
2292 | ||
2293 | unsigned HOST_WIDE_INT end = len; | |
2294 | unsigned HOST_WIDE_INT begin = 0; | |
2295 | ||
2296 | /* If the last element of the CONSTRUCTOR has its own index, we can assume | |
2297 | that the same is true of the other elements and index directly. */ | |
2298 | if (end > 0) | |
2299 | { | |
e99466d6 | 2300 | tree cindex = (*elts)[end - 1].index; |
7963b19d | 2301 | if (TREE_CODE (cindex) == INTEGER_CST |
e99466d6 | 2302 | && compare_tree_int (cindex, end - 1) == 0) |
7963b19d | 2303 | { |
2304 | if (i < end) | |
2305 | return i; | |
2306 | else | |
2307 | begin = end; | |
2308 | } | |
2309 | } | |
2310 | ||
2311 | /* Otherwise, find a matching index by means of a binary search. */ | |
2312 | while (begin != end) | |
2313 | { | |
2314 | unsigned HOST_WIDE_INT middle = (begin + end) / 2; | |
f0b916c7 | 2315 | constructor_elt &elt = (*elts)[middle]; |
2316 | tree idx = elt.index; | |
7963b19d | 2317 | |
f0b916c7 | 2318 | int cmp = array_index_cmp (dindex, idx); |
7963b19d | 2319 | if (cmp < 0) |
2320 | end = middle; | |
2321 | else if (cmp > 0) | |
2322 | begin = middle + 1; | |
2323 | else | |
f0b916c7 | 2324 | { |
2325 | if (insert && TREE_CODE (idx) == RANGE_EXPR) | |
2326 | { | |
2327 | /* We need to split the range. */ | |
2328 | constructor_elt e; | |
2329 | tree lo = TREE_OPERAND (idx, 0); | |
2330 | tree hi = TREE_OPERAND (idx, 1); | |
e99466d6 | 2331 | tree value = elt.value; |
2332 | dindex = fold_convert (sizetype, dindex); | |
f0b916c7 | 2333 | if (tree_int_cst_lt (lo, dindex)) |
2334 | { | |
2335 | /* There are still some lower elts; shorten the range. */ | |
2336 | tree new_hi = int_const_binop (MINUS_EXPR, dindex, | |
2337 | size_one_node); | |
2338 | if (tree_int_cst_equal (lo, new_hi)) | |
2339 | /* Only one element left, no longer a range. */ | |
2340 | elt.index = lo; | |
2341 | else | |
2342 | TREE_OPERAND (idx, 1) = new_hi; | |
2343 | /* Append the element we want to insert. */ | |
2344 | ++middle; | |
2345 | e.index = dindex; | |
e99466d6 | 2346 | e.value = unshare_constructor (value); |
f0b916c7 | 2347 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle, e); |
2348 | } | |
2349 | else | |
2350 | /* No lower elts, the range elt is now ours. */ | |
2351 | elt.index = dindex; | |
2352 | ||
2353 | if (tree_int_cst_lt (dindex, hi)) | |
2354 | { | |
2355 | /* There are still some higher elts; append a range. */ | |
2356 | tree new_lo = int_const_binop (PLUS_EXPR, dindex, | |
2357 | size_one_node); | |
2358 | if (tree_int_cst_equal (new_lo, hi)) | |
2359 | e.index = hi; | |
2360 | else | |
2361 | e.index = build2 (RANGE_EXPR, sizetype, new_lo, hi); | |
e99466d6 | 2362 | e.value = unshare_constructor (value); |
2363 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle + 1, e); | |
f0b916c7 | 2364 | } |
2365 | } | |
2366 | return middle; | |
2367 | } | |
7963b19d | 2368 | } |
2369 | ||
2370 | if (insert) | |
2371 | { | |
2372 | constructor_elt e = { dindex, NULL_TREE }; | |
2373 | vec_safe_insert (CONSTRUCTOR_ELTS (ary), end, e); | |
2374 | return end; | |
2375 | } | |
2376 | ||
2377 | return -1; | |
2378 | } | |
2379 | ||
40df9099 | 2380 | /* Under the control of CTX, issue a detailed diagnostic for |
2381 | an out-of-bounds subscript INDEX into the expression ARRAY. */ | |
2382 | ||
2383 | static void | |
2384 | diag_array_subscript (const constexpr_ctx *ctx, tree array, tree index) | |
2385 | { | |
2386 | if (!ctx->quiet) | |
2387 | { | |
2388 | tree arraytype = TREE_TYPE (array); | |
2389 | ||
2390 | /* Convert the unsigned array subscript to a signed integer to avoid | |
2391 | printing huge numbers for small negative values. */ | |
2392 | tree sidx = fold_convert (ssizetype, index); | |
2393 | if (DECL_P (array)) | |
2394 | { | |
d7d265db | 2395 | if (TYPE_DOMAIN (arraytype)) |
2396 | error ("array subscript value %qE is outside the bounds " | |
2397 | "of array %qD of type %qT", sidx, array, arraytype); | |
2398 | else | |
2399 | error ("non-zero array subscript %qE is used with array %qD of " | |
2400 | "type %qT with unknown bounds", sidx, array, arraytype); | |
40df9099 | 2401 | inform (DECL_SOURCE_LOCATION (array), "declared here"); |
2402 | } | |
d7d265db | 2403 | else if (TYPE_DOMAIN (arraytype)) |
40df9099 | 2404 | error ("array subscript value %qE is outside the bounds " |
2405 | "of array type %qT", sidx, arraytype); | |
d7d265db | 2406 | else |
2407 | error ("non-zero array subscript %qE is used with array of type %qT " | |
2408 | "with unknown bounds", sidx, arraytype); | |
40df9099 | 2409 | } |
2410 | } | |
7963b19d | 2411 | |
51f0c7e2 | 2412 | /* Return the number of elements for TYPE (which is an ARRAY_TYPE or |
2413 | a VECTOR_TYPE). */ | |
2414 | ||
2415 | static tree | |
2416 | get_array_or_vector_nelts (const constexpr_ctx *ctx, tree type, | |
2417 | bool *non_constant_p, bool *overflow_p) | |
2418 | { | |
2419 | tree nelts; | |
2420 | if (TREE_CODE (type) == ARRAY_TYPE) | |
2421 | { | |
2422 | if (TYPE_DOMAIN (type)) | |
2423 | nelts = array_type_nelts_top (type); | |
2424 | else | |
2425 | nelts = size_zero_node; | |
2426 | } | |
2427 | else if (VECTOR_TYPE_P (type)) | |
2428 | nelts = size_int (TYPE_VECTOR_SUBPARTS (type)); | |
2429 | else | |
2430 | gcc_unreachable (); | |
2431 | ||
2432 | /* For VLAs, the number of elements won't be an integer constant. */ | |
2433 | nelts = cxx_eval_constant_expression (ctx, nelts, false, | |
2434 | non_constant_p, overflow_p); | |
2435 | return nelts; | |
2436 | } | |
2437 | ||
92fe8840 | 2438 | /* Extract element INDEX consisting of CHARS_PER_ELT chars from |
2439 | STRING_CST STRING. */ | |
2440 | ||
2441 | static tree | |
2442 | extract_string_elt (tree string, unsigned chars_per_elt, unsigned index) | |
2443 | { | |
2444 | tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (string))); | |
2445 | tree r; | |
2446 | ||
2447 | if (chars_per_elt == 1) | |
2448 | r = build_int_cst (type, TREE_STRING_POINTER (string)[index]); | |
2449 | else | |
2450 | { | |
2451 | const unsigned char *ptr | |
2452 | = ((const unsigned char *)TREE_STRING_POINTER (string) | |
2453 | + index * chars_per_elt); | |
2454 | r = native_interpret_expr (type, ptr, chars_per_elt); | |
2455 | } | |
2456 | return r; | |
2457 | } | |
2458 | ||
09b42213 | 2459 | /* Subroutine of cxx_eval_constant_expression. |
2460 | Attempt to reduce a reference to an array slot. */ | |
2461 | ||
2462 | static tree | |
cf72f34d | 2463 | cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2464 | bool lval, |
09b42213 | 2465 | bool *non_constant_p, bool *overflow_p) |
2466 | { | |
2467 | tree oldary = TREE_OPERAND (t, 0); | |
cf72f34d | 2468 | tree ary = cxx_eval_constant_expression (ctx, oldary, |
1227ba74 | 2469 | lval, |
b2a43197 | 2470 | non_constant_p, overflow_p); |
09b42213 | 2471 | tree index, oldidx; |
cf3cefc9 | 2472 | HOST_WIDE_INT i = 0; |
2473 | tree elem_type = NULL_TREE; | |
2474 | unsigned len = 0, elem_nchars = 1; | |
09b42213 | 2475 | if (*non_constant_p) |
2476 | return t; | |
2477 | oldidx = TREE_OPERAND (t, 1); | |
cf72f34d | 2478 | index = cxx_eval_constant_expression (ctx, oldidx, |
f83e6885 | 2479 | false, |
b2a43197 | 2480 | non_constant_p, overflow_p); |
09b42213 | 2481 | VERIFY_CONSTANT (index); |
cf3cefc9 | 2482 | if (!lval) |
09b42213 | 2483 | { |
cf3cefc9 | 2484 | elem_type = TREE_TYPE (TREE_TYPE (ary)); |
2485 | if (TREE_CODE (ary) == VIEW_CONVERT_EXPR | |
2486 | && VECTOR_TYPE_P (TREE_TYPE (TREE_OPERAND (ary, 0))) | |
2487 | && TREE_TYPE (t) == TREE_TYPE (TREE_TYPE (TREE_OPERAND (ary, 0)))) | |
2488 | ary = TREE_OPERAND (ary, 0); | |
2489 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2490 | len = CONSTRUCTOR_NELTS (ary); | |
2491 | else if (TREE_CODE (ary) == STRING_CST) | |
2492 | { | |
2493 | elem_nchars = (TYPE_PRECISION (elem_type) | |
2494 | / TYPE_PRECISION (char_type_node)); | |
2495 | len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars; | |
2496 | } | |
2497 | else if (TREE_CODE (ary) == VECTOR_CST) | |
f08ee65f | 2498 | /* We don't create variable-length VECTOR_CSTs. */ |
2499 | len = VECTOR_CST_NELTS (ary).to_constant (); | |
cf3cefc9 | 2500 | else |
2501 | { | |
2502 | /* We can't do anything with other tree codes, so use | |
2503 | VERIFY_CONSTANT to complain and fail. */ | |
2504 | VERIFY_CONSTANT (ary); | |
2505 | gcc_unreachable (); | |
2506 | } | |
aed8dc7f | 2507 | |
cf3cefc9 | 2508 | if (!tree_fits_shwi_p (index) |
2509 | || (i = tree_to_shwi (index)) < 0) | |
2510 | { | |
2511 | diag_array_subscript (ctx, ary, index); | |
2512 | *non_constant_p = true; | |
2513 | return t; | |
2514 | } | |
7963b19d | 2515 | } |
2516 | ||
51f0c7e2 | 2517 | tree nelts = get_array_or_vector_nelts (ctx, TREE_TYPE (ary), non_constant_p, |
2518 | overflow_p); | |
ce6a6978 | 2519 | VERIFY_CONSTANT (nelts); |
0acc6340 | 2520 | if ((lval |
2521 | ? !tree_int_cst_le (index, nelts) | |
2522 | : !tree_int_cst_lt (index, nelts)) | |
2523 | || tree_int_cst_sgn (index) < 0) | |
ce6a6978 | 2524 | { |
40df9099 | 2525 | diag_array_subscript (ctx, ary, index); |
ce6a6978 | 2526 | *non_constant_p = true; |
2527 | return t; | |
2528 | } | |
2529 | ||
cf3cefc9 | 2530 | if (lval && ary == oldary && index == oldidx) |
2531 | return t; | |
2532 | else if (lval) | |
2533 | return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL); | |
2534 | ||
7963b19d | 2535 | bool found; |
2536 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2537 | { | |
2538 | HOST_WIDE_INT ix = find_array_ctor_elt (ary, index); | |
2539 | found = (ix >= 0); | |
2540 | if (found) | |
2541 | i = ix; | |
aed8dc7f | 2542 | } |
7963b19d | 2543 | else |
2544 | found = (i < len); | |
aed8dc7f | 2545 | |
14869f28 | 2546 | if (found) |
2547 | { | |
2548 | tree r; | |
2549 | if (TREE_CODE (ary) == CONSTRUCTOR) | |
2550 | r = (*CONSTRUCTOR_ELTS (ary))[i].value; | |
2551 | else if (TREE_CODE (ary) == VECTOR_CST) | |
2552 | r = VECTOR_CST_ELT (ary, i); | |
14869f28 | 2553 | else |
92fe8840 | 2554 | r = extract_string_elt (ary, elem_nchars, i); |
2555 | ||
14869f28 | 2556 | if (r) |
2557 | /* Don't VERIFY_CONSTANT here. */ | |
2558 | return r; | |
09b42213 | 2559 | |
14869f28 | 2560 | /* Otherwise the element doesn't have a value yet. */ |
09b42213 | 2561 | } |
aed8dc7f | 2562 | |
14869f28 | 2563 | /* Not found. */ |
2564 | ||
2565 | if (TREE_CODE (ary) == CONSTRUCTOR | |
165d0d5b | 2566 | && CONSTRUCTOR_NO_CLEARING (ary)) |
09b42213 | 2567 | { |
14869f28 | 2568 | /* 'ary' is part of the aggregate initializer we're currently |
2569 | building; if there's no initializer for this element yet, | |
2570 | that's an error. */ | |
2571 | if (!ctx->quiet) | |
2572 | error ("accessing uninitialized array element"); | |
2573 | *non_constant_p = true; | |
2574 | return t; | |
09b42213 | 2575 | } |
14869f28 | 2576 | |
2577 | /* If it's within the array bounds but doesn't have an explicit | |
2578 | initializer, it's value-initialized. */ | |
2579 | tree val = build_value_init (elem_type, tf_warning_or_error); | |
2580 | return cxx_eval_constant_expression (ctx, val, lval, non_constant_p, | |
2581 | overflow_p); | |
09b42213 | 2582 | } |
2583 | ||
2584 | /* Subroutine of cxx_eval_constant_expression. | |
2585 | Attempt to reduce a field access of a value of class type. */ | |
2586 | ||
2587 | static tree | |
cf72f34d | 2588 | cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2589 | bool lval, |
09b42213 | 2590 | bool *non_constant_p, bool *overflow_p) |
2591 | { | |
2592 | unsigned HOST_WIDE_INT i; | |
2593 | tree field; | |
2594 | tree value; | |
2595 | tree part = TREE_OPERAND (t, 1); | |
2596 | tree orig_whole = TREE_OPERAND (t, 0); | |
cf72f34d | 2597 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2598 | lval, |
b2a43197 | 2599 | non_constant_p, overflow_p); |
7ab20d7c | 2600 | if (INDIRECT_REF_P (whole) |
2b1749c4 | 2601 | && integer_zerop (TREE_OPERAND (whole, 0))) |
2602 | { | |
2603 | if (!ctx->quiet) | |
2604 | error ("dereferencing a null pointer in %qE", orig_whole); | |
2605 | *non_constant_p = true; | |
2606 | return t; | |
2607 | } | |
cb768824 | 2608 | |
f16ed232 | 2609 | if (TREE_CODE (whole) == PTRMEM_CST) |
2610 | whole = cplus_expand_constant (whole); | |
09b42213 | 2611 | if (whole == orig_whole) |
2612 | return t; | |
1227ba74 | 2613 | if (lval) |
09b42213 | 2614 | return fold_build3 (COMPONENT_REF, TREE_TYPE (t), |
2615 | whole, part, NULL_TREE); | |
2616 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2617 | CONSTRUCTOR. */ | |
2618 | if (!*non_constant_p && TREE_CODE (whole) != CONSTRUCTOR) | |
2619 | { | |
f83e6885 | 2620 | if (!ctx->quiet) |
09b42213 | 2621 | error ("%qE is not a constant expression", orig_whole); |
2622 | *non_constant_p = true; | |
2623 | } | |
2624 | if (DECL_MUTABLE_P (part)) | |
2625 | { | |
f83e6885 | 2626 | if (!ctx->quiet) |
09b42213 | 2627 | error ("mutable %qD is not usable in a constant expression", part); |
2628 | *non_constant_p = true; | |
2629 | } | |
2630 | if (*non_constant_p) | |
2631 | return t; | |
a4360e57 | 2632 | bool pmf = TYPE_PTRMEMFUNC_P (TREE_TYPE (whole)); |
09b42213 | 2633 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) |
2634 | { | |
a4360e57 | 2635 | /* Use name match for PMF fields, as a variant will have a |
2636 | different FIELD_DECL with a different type. */ | |
2637 | if (pmf ? DECL_NAME (field) == DECL_NAME (part) | |
2638 | : field == part) | |
9c96033c | 2639 | { |
2640 | if (value) | |
2641 | return value; | |
2642 | else | |
2643 | /* We're in the middle of initializing it. */ | |
2644 | break; | |
2645 | } | |
09b42213 | 2646 | } |
2647 | if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE | |
2648 | && CONSTRUCTOR_NELTS (whole) > 0) | |
2649 | { | |
2650 | /* DR 1188 says we don't have to deal with this. */ | |
f83e6885 | 2651 | if (!ctx->quiet) |
09b42213 | 2652 | error ("accessing %qD member instead of initialized %qD member in " |
2653 | "constant expression", part, CONSTRUCTOR_ELT (whole, 0)->index); | |
2654 | *non_constant_p = true; | |
2655 | return t; | |
2656 | } | |
2657 | ||
f894a056 | 2658 | /* We only create a CONSTRUCTOR for a subobject when we modify it, so empty |
2659 | classes never get represented; throw together a value now. */ | |
2660 | if (is_really_empty_class (TREE_TYPE (t))) | |
2661 | return build_constructor (TREE_TYPE (t), NULL); | |
2662 | ||
a4360e57 | 2663 | gcc_assert (DECL_CONTEXT (part) == TYPE_MAIN_VARIANT (TREE_TYPE (whole))); |
2664 | ||
165d0d5b | 2665 | if (CONSTRUCTOR_NO_CLEARING (whole)) |
cf72f34d | 2666 | { |
2667 | /* 'whole' is part of the aggregate initializer we're currently | |
2668 | building; if there's no initializer for this member yet, that's an | |
f894a056 | 2669 | error. */ |
f83e6885 | 2670 | if (!ctx->quiet) |
cf72f34d | 2671 | error ("accessing uninitialized member %qD", part); |
2672 | *non_constant_p = true; | |
2673 | return t; | |
2674 | } | |
2675 | ||
09b42213 | 2676 | /* If there's no explicit init for this field, it's value-initialized. */ |
2677 | value = build_value_init (TREE_TYPE (t), tf_warning_or_error); | |
cf72f34d | 2678 | return cxx_eval_constant_expression (ctx, value, |
1227ba74 | 2679 | lval, |
b2a43197 | 2680 | non_constant_p, overflow_p); |
09b42213 | 2681 | } |
2682 | ||
2683 | /* Subroutine of cxx_eval_constant_expression. | |
2684 | Attempt to reduce a field access of a value of class type that is | |
2685 | expressed as a BIT_FIELD_REF. */ | |
2686 | ||
2687 | static tree | |
cf72f34d | 2688 | cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2689 | bool lval, |
09b42213 | 2690 | bool *non_constant_p, bool *overflow_p) |
2691 | { | |
2692 | tree orig_whole = TREE_OPERAND (t, 0); | |
2693 | tree retval, fldval, utype, mask; | |
2694 | bool fld_seen = false; | |
2695 | HOST_WIDE_INT istart, isize; | |
cf72f34d | 2696 | tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
1227ba74 | 2697 | lval, |
b2a43197 | 2698 | non_constant_p, overflow_p); |
09b42213 | 2699 | tree start, field, value; |
2700 | unsigned HOST_WIDE_INT i; | |
2701 | ||
2702 | if (whole == orig_whole) | |
2703 | return t; | |
2704 | /* Don't VERIFY_CONSTANT here; we only want to check that we got a | |
2705 | CONSTRUCTOR. */ | |
2706 | if (!*non_constant_p | |
2707 | && TREE_CODE (whole) != VECTOR_CST | |
2708 | && TREE_CODE (whole) != CONSTRUCTOR) | |
2709 | { | |
f83e6885 | 2710 | if (!ctx->quiet) |
09b42213 | 2711 | error ("%qE is not a constant expression", orig_whole); |
2712 | *non_constant_p = true; | |
2713 | } | |
2714 | if (*non_constant_p) | |
2715 | return t; | |
2716 | ||
2717 | if (TREE_CODE (whole) == VECTOR_CST) | |
2718 | return fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole, | |
2719 | TREE_OPERAND (t, 1), TREE_OPERAND (t, 2)); | |
2720 | ||
2721 | start = TREE_OPERAND (t, 2); | |
2722 | istart = tree_to_shwi (start); | |
2723 | isize = tree_to_shwi (TREE_OPERAND (t, 1)); | |
2724 | utype = TREE_TYPE (t); | |
2725 | if (!TYPE_UNSIGNED (utype)) | |
2726 | utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1); | |
2727 | retval = build_int_cst (utype, 0); | |
2728 | FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) | |
2729 | { | |
2730 | tree bitpos = bit_position (field); | |
2731 | if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1)) | |
2732 | return value; | |
2733 | if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE | |
2734 | && TREE_CODE (value) == INTEGER_CST | |
2735 | && tree_fits_shwi_p (bitpos) | |
2736 | && tree_fits_shwi_p (DECL_SIZE (field))) | |
2737 | { | |
2738 | HOST_WIDE_INT bit = tree_to_shwi (bitpos); | |
2739 | HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field)); | |
2740 | HOST_WIDE_INT shift; | |
2741 | if (bit >= istart && bit + sz <= istart + isize) | |
2742 | { | |
2743 | fldval = fold_convert (utype, value); | |
2744 | mask = build_int_cst_type (utype, -1); | |
2745 | mask = fold_build2 (LSHIFT_EXPR, utype, mask, | |
2746 | size_int (TYPE_PRECISION (utype) - sz)); | |
2747 | mask = fold_build2 (RSHIFT_EXPR, utype, mask, | |
2748 | size_int (TYPE_PRECISION (utype) - sz)); | |
2749 | fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask); | |
2750 | shift = bit - istart; | |
2751 | if (BYTES_BIG_ENDIAN) | |
2752 | shift = TYPE_PRECISION (utype) - shift - sz; | |
2753 | fldval = fold_build2 (LSHIFT_EXPR, utype, fldval, | |
2754 | size_int (shift)); | |
2755 | retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval); | |
2756 | fld_seen = true; | |
2757 | } | |
2758 | } | |
2759 | } | |
2760 | if (fld_seen) | |
2761 | return fold_convert (TREE_TYPE (t), retval); | |
2762 | gcc_unreachable (); | |
2763 | return error_mark_node; | |
2764 | } | |
2765 | ||
2766 | /* Subroutine of cxx_eval_constant_expression. | |
2767 | Evaluate a short-circuited logical expression T in the context | |
2768 | of a given constexpr CALL. BAILOUT_VALUE is the value for | |
2769 | early return. CONTINUE_VALUE is used here purely for | |
2770 | sanity check purposes. */ | |
2771 | ||
2772 | static tree | |
cf72f34d | 2773 | cxx_eval_logical_expression (const constexpr_ctx *ctx, tree t, |
09b42213 | 2774 | tree bailout_value, tree continue_value, |
1227ba74 | 2775 | bool lval, |
09b42213 | 2776 | bool *non_constant_p, bool *overflow_p) |
2777 | { | |
2778 | tree r; | |
cf72f34d | 2779 | tree lhs = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 2780 | lval, |
b2a43197 | 2781 | non_constant_p, overflow_p); |
09b42213 | 2782 | VERIFY_CONSTANT (lhs); |
2783 | if (tree_int_cst_equal (lhs, bailout_value)) | |
2784 | return lhs; | |
2785 | gcc_assert (tree_int_cst_equal (lhs, continue_value)); | |
cf72f34d | 2786 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 2787 | lval, non_constant_p, |
b2a43197 | 2788 | overflow_p); |
09b42213 | 2789 | VERIFY_CONSTANT (r); |
2790 | return r; | |
2791 | } | |
2792 | ||
2793 | /* REF is a COMPONENT_REF designating a particular field. V is a vector of | |
2794 | CONSTRUCTOR elements to initialize (part of) an object containing that | |
2795 | field. Return a pointer to the constructor_elt corresponding to the | |
2796 | initialization of the field. */ | |
2797 | ||
2798 | static constructor_elt * | |
2799 | base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref) | |
2800 | { | |
2801 | tree aggr = TREE_OPERAND (ref, 0); | |
2802 | tree field = TREE_OPERAND (ref, 1); | |
2803 | HOST_WIDE_INT i; | |
2804 | constructor_elt *ce; | |
2805 | ||
2806 | gcc_assert (TREE_CODE (ref) == COMPONENT_REF); | |
2807 | ||
2808 | if (TREE_CODE (aggr) == COMPONENT_REF) | |
2809 | { | |
2810 | constructor_elt *base_ce | |
2811 | = base_field_constructor_elt (v, aggr); | |
2812 | v = CONSTRUCTOR_ELTS (base_ce->value); | |
2813 | } | |
2814 | ||
2815 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2816 | if (ce->index == field) | |
2817 | return ce; | |
2818 | ||
2819 | gcc_unreachable (); | |
2820 | return NULL; | |
2821 | } | |
2822 | ||
cf72f34d | 2823 | /* Some of the expressions fed to the constexpr mechanism are calls to |
2824 | constructors, which have type void. In that case, return the type being | |
2825 | initialized by the constructor. */ | |
2826 | ||
2827 | static tree | |
2828 | initialized_type (tree t) | |
2829 | { | |
2830 | if (TYPE_P (t)) | |
2831 | return t; | |
59183fff | 2832 | tree type = TREE_TYPE (t); |
2833 | if (!VOID_TYPE_P (type)) | |
2834 | /* No need to look deeper. */; | |
2835 | else if (TREE_CODE (t) == CALL_EXPR) | |
cf72f34d | 2836 | { |
2837 | /* A constructor call has void type, so we need to look deeper. */ | |
2838 | tree fn = get_function_named_in_call (t); | |
2839 | if (fn && TREE_CODE (fn) == FUNCTION_DECL | |
2840 | && DECL_CXX_CONSTRUCTOR_P (fn)) | |
2841 | type = DECL_CONTEXT (fn); | |
2842 | } | |
59183fff | 2843 | else if (TREE_CODE (t) == AGGR_INIT_EXPR) |
2844 | type = TREE_TYPE (AGGR_INIT_EXPR_SLOT (t)); | |
2845 | return cv_unqualified (type); | |
cf72f34d | 2846 | } |
2847 | ||
2848 | /* We're about to initialize element INDEX of an array or class from VALUE. | |
2849 | Set up NEW_CTX appropriately by adjusting .object to refer to the | |
2850 | subobject and creating a new CONSTRUCTOR if the element is itself | |
2851 | a class or array. */ | |
2852 | ||
2853 | static void | |
2854 | init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, | |
2855 | tree index, tree &value) | |
2856 | { | |
2857 | new_ctx = *ctx; | |
2858 | ||
2859 | if (index && TREE_CODE (index) != INTEGER_CST | |
2860 | && TREE_CODE (index) != FIELD_DECL) | |
2861 | /* This won't have an element in the new CONSTRUCTOR. */ | |
2862 | return; | |
2863 | ||
2864 | tree type = initialized_type (value); | |
2865 | if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) | |
2866 | /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ | |
2867 | return; | |
2868 | ||
2869 | /* The sub-aggregate initializer might contain a placeholder; | |
2870 | update object to refer to the subobject and ctor to refer to | |
2871 | the (newly created) sub-initializer. */ | |
2872 | if (ctx->object) | |
2873 | new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); | |
2874 | tree elt = build_constructor (type, NULL); | |
165d0d5b | 2875 | CONSTRUCTOR_NO_CLEARING (elt) = true; |
cf72f34d | 2876 | new_ctx.ctor = elt; |
2877 | ||
2878 | if (TREE_CODE (value) == TARGET_EXPR) | |
2879 | /* Avoid creating another CONSTRUCTOR when we expand the TARGET_EXPR. */ | |
2880 | value = TARGET_EXPR_INITIAL (value); | |
2881 | } | |
2882 | ||
2883 | /* We're about to process an initializer for a class or array TYPE. Make | |
2884 | sure that CTX is set up appropriately. */ | |
2885 | ||
2886 | static void | |
2887 | verify_ctor_sanity (const constexpr_ctx *ctx, tree type) | |
2888 | { | |
2889 | /* We don't bother building a ctor for an empty base subobject. */ | |
2890 | if (is_empty_class (type)) | |
2891 | return; | |
2892 | ||
2893 | /* We're in the middle of an initializer that might involve placeholders; | |
2894 | our caller should have created a CONSTRUCTOR for us to put the | |
2895 | initializer into. We will either return that constructor or T. */ | |
2896 | gcc_assert (ctx->ctor); | |
2897 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
2898 | (type, TREE_TYPE (ctx->ctor))); | |
bbf58224 | 2899 | /* We used to check that ctx->ctor was empty, but that isn't the case when |
2900 | the object is zero-initialized before calling the constructor. */ | |
cf72f34d | 2901 | if (ctx->object) |
d9751a3c | 2902 | { |
2903 | tree otype = TREE_TYPE (ctx->object); | |
2904 | gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, otype) | |
2905 | /* Handle flexible array members. */ | |
2906 | || (TREE_CODE (otype) == ARRAY_TYPE | |
2907 | && TYPE_DOMAIN (otype) == NULL_TREE | |
2908 | && TREE_CODE (type) == ARRAY_TYPE | |
2909 | && (same_type_ignoring_top_level_qualifiers_p | |
2910 | (TREE_TYPE (type), TREE_TYPE (otype))))); | |
2911 | } | |
cf72f34d | 2912 | gcc_assert (!ctx->object || !DECL_P (ctx->object) |
2913 | || *(ctx->values->get (ctx->object)) == ctx->ctor); | |
2914 | } | |
2915 | ||
09b42213 | 2916 | /* Subroutine of cxx_eval_constant_expression. |
2917 | The expression tree T denotes a C-style array or a C-style | |
2918 | aggregate. Reduce it to a constant expression. */ | |
2919 | ||
2920 | static tree | |
cf72f34d | 2921 | cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, |
1227ba74 | 2922 | bool lval, |
09b42213 | 2923 | bool *non_constant_p, bool *overflow_p) |
2924 | { | |
2925 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
09b42213 | 2926 | bool changed = false; |
2927 | gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t)); | |
68464393 | 2928 | tree type = TREE_TYPE (t); |
cf72f34d | 2929 | |
68464393 | 2930 | constexpr_ctx new_ctx; |
d2dd85e3 | 2931 | if (TYPE_PTRMEMFUNC_P (type) || VECTOR_TYPE_P (type)) |
68464393 | 2932 | { |
d2dd85e3 | 2933 | /* We don't really need the ctx->ctor business for a PMF or |
2934 | vector, but it's simpler to use the same code. */ | |
68464393 | 2935 | new_ctx = *ctx; |
2936 | new_ctx.ctor = build_constructor (type, NULL); | |
2937 | new_ctx.object = NULL_TREE; | |
2938 | ctx = &new_ctx; | |
2939 | }; | |
2940 | verify_ctor_sanity (ctx, type); | |
cf72f34d | 2941 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); |
2942 | vec_alloc (*p, vec_safe_length (v)); | |
2943 | ||
58b0f9ce | 2944 | unsigned i; |
2945 | tree index, value; | |
2946 | bool constant_p = true; | |
2947 | bool side_effects_p = false; | |
cf72f34d | 2948 | FOR_EACH_CONSTRUCTOR_ELT (v, i, index, value) |
09b42213 | 2949 | { |
5ae773e4 | 2950 | tree orig_value = value; |
cf72f34d | 2951 | init_subob_ctx (ctx, new_ctx, index, value); |
2952 | if (new_ctx.ctor != ctx->ctor) | |
2953 | /* If we built a new CONSTRUCTOR, attach it now so that other | |
2954 | initializers can refer to it. */ | |
2955 | CONSTRUCTOR_APPEND_ELT (*p, index, new_ctx.ctor); | |
2956 | tree elt = cxx_eval_constant_expression (&new_ctx, value, | |
1227ba74 | 2957 | lval, |
b2a43197 | 2958 | non_constant_p, overflow_p); |
09b42213 | 2959 | /* Don't VERIFY_CONSTANT here. */ |
f83e6885 | 2960 | if (ctx->quiet && *non_constant_p) |
cf72f34d | 2961 | break; |
5ae773e4 | 2962 | if (elt != orig_value) |
09b42213 | 2963 | changed = true; |
58b0f9ce | 2964 | |
2965 | if (!TREE_CONSTANT (elt)) | |
2966 | constant_p = false; | |
2967 | if (TREE_SIDE_EFFECTS (elt)) | |
2968 | side_effects_p = true; | |
cf72f34d | 2969 | if (index && TREE_CODE (index) == COMPONENT_REF) |
09b42213 | 2970 | { |
2971 | /* This is an initialization of a vfield inside a base | |
2972 | subaggregate that we already initialized; push this | |
2973 | initialization into the previous initialization. */ | |
cf72f34d | 2974 | constructor_elt *inner = base_field_constructor_elt (*p, index); |
09b42213 | 2975 | inner->value = elt; |
cf72f34d | 2976 | changed = true; |
09b42213 | 2977 | } |
cf72f34d | 2978 | else if (index |
2979 | && (TREE_CODE (index) == NOP_EXPR | |
2980 | || TREE_CODE (index) == POINTER_PLUS_EXPR)) | |
09b42213 | 2981 | { |
2982 | /* This is an initializer for an empty base; now that we've | |
2983 | checked that it's constant, we can ignore it. */ | |
cf72f34d | 2984 | gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (index)))); |
2985 | changed = true; | |
2986 | } | |
09b42213 | 2987 | else |
79e65a6b | 2988 | { |
0dd49b5a | 2989 | if (new_ctx.ctor != ctx->ctor) |
2990 | { | |
2991 | /* We appended this element above; update the value. */ | |
2992 | gcc_assert ((*p)->last().index == index); | |
2993 | (*p)->last().value = elt; | |
2994 | } | |
2995 | else | |
2996 | CONSTRUCTOR_APPEND_ELT (*p, index, elt); | |
2997 | /* Adding or replacing an element might change the ctor's flags. */ | |
79e65a6b | 2998 | TREE_CONSTANT (ctx->ctor) = constant_p; |
2999 | TREE_SIDE_EFFECTS (ctx->ctor) = side_effects_p; | |
3000 | } | |
09b42213 | 3001 | } |
3002 | if (*non_constant_p || !changed) | |
cf72f34d | 3003 | return t; |
3004 | t = ctx->ctor; | |
3005 | /* We're done building this CONSTRUCTOR, so now we can interpret an | |
3006 | element without an explicit initializer as value-initialized. */ | |
165d0d5b | 3007 | CONSTRUCTOR_NO_CLEARING (t) = false; |
58b0f9ce | 3008 | TREE_CONSTANT (t) = constant_p; |
3009 | TREE_SIDE_EFFECTS (t) = side_effects_p; | |
68464393 | 3010 | if (VECTOR_TYPE_P (type)) |
09b42213 | 3011 | t = fold (t); |
3012 | return t; | |
3013 | } | |
3014 | ||
3015 | /* Subroutine of cxx_eval_constant_expression. | |
3016 | The expression tree T is a VEC_INIT_EXPR which denotes the desired | |
3017 | initialization of a non-static data member of array type. Reduce it to a | |
3018 | CONSTRUCTOR. | |
3019 | ||
3020 | Note that apart from value-initialization (when VALUE_INIT is true), | |
3021 | this is only intended to support value-initialization and the | |
3022 | initializations done by defaulted constructors for classes with | |
3023 | non-static data members of array type. In this case, VEC_INIT_EXPR_INIT | |
3024 | will either be NULL_TREE for the default constructor, or a COMPONENT_REF | |
3025 | for the copy/move constructor. */ | |
3026 | ||
3027 | static tree | |
cf72f34d | 3028 | cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, |
1227ba74 | 3029 | bool value_init, bool lval, |
09b42213 | 3030 | bool *non_constant_p, bool *overflow_p) |
3031 | { | |
3032 | tree elttype = TREE_TYPE (atype); | |
cf72f34d | 3033 | verify_ctor_sanity (ctx, atype); |
3034 | vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); | |
09b42213 | 3035 | bool pre_init = false; |
3e520b97 | 3036 | unsigned HOST_WIDE_INT i; |
c4970310 | 3037 | tsubst_flags_t complain = ctx->quiet ? tf_none : tf_warning_or_error; |
09b42213 | 3038 | |
3039 | /* For the default constructor, build up a call to the default | |
3040 | constructor of the element type. We only need to handle class types | |
3041 | here, as for a constructor to be constexpr, all members must be | |
3042 | initialized, which for a defaulted default constructor means they must | |
3043 | be of a class type with a constexpr default constructor. */ | |
3044 | if (TREE_CODE (elttype) == ARRAY_TYPE) | |
3045 | /* We only do this at the lowest level. */; | |
3046 | else if (value_init) | |
3047 | { | |
c4970310 | 3048 | init = build_value_init (elttype, complain); |
09b42213 | 3049 | pre_init = true; |
3050 | } | |
3051 | else if (!init) | |
3052 | { | |
3053 | vec<tree, va_gc> *argvec = make_tree_vector (); | |
3054 | init = build_special_member_call (NULL_TREE, complete_ctor_identifier, | |
3055 | &argvec, elttype, LOOKUP_NORMAL, | |
c4970310 | 3056 | complain); |
09b42213 | 3057 | release_tree_vector (argvec); |
59183fff | 3058 | init = build_aggr_init_expr (elttype, init); |
09b42213 | 3059 | pre_init = true; |
3060 | } | |
3061 | ||
51f0c7e2 | 3062 | tree nelts = get_array_or_vector_nelts (ctx, atype, non_constant_p, |
3063 | overflow_p); | |
3064 | unsigned HOST_WIDE_INT max = tree_to_uhwi (nelts); | |
3e520b97 | 3065 | for (i = 0; i < max; ++i) |
09b42213 | 3066 | { |
3067 | tree idx = build_int_cst (size_type_node, i); | |
3068 | tree eltinit; | |
d9377ad5 | 3069 | bool reuse = false; |
cf72f34d | 3070 | constexpr_ctx new_ctx; |
3071 | init_subob_ctx (ctx, new_ctx, idx, pre_init ? init : elttype); | |
3072 | if (new_ctx.ctor != ctx->ctor) | |
3073 | CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor); | |
09b42213 | 3074 | if (TREE_CODE (elttype) == ARRAY_TYPE) |
3075 | { | |
3076 | /* A multidimensional array; recurse. */ | |
3077 | if (value_init || init == NULL_TREE) | |
d9377ad5 | 3078 | { |
3079 | eltinit = NULL_TREE; | |
3080 | reuse = i == 0; | |
3081 | } | |
09b42213 | 3082 | else |
c4970310 | 3083 | eltinit = cp_build_array_ref (input_location, init, idx, complain); |
cf72f34d | 3084 | eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, value_init, |
1227ba74 | 3085 | lval, |
09b42213 | 3086 | non_constant_p, overflow_p); |
3087 | } | |
3088 | else if (pre_init) | |
3089 | { | |
3090 | /* Initializing an element using value or default initialization | |
3091 | we just pre-built above. */ | |
0e9064d2 | 3092 | if (init == void_node) |
3093 | /* Trivial default-init, don't do anything to the CONSTRUCTOR. */ | |
3094 | return ctx->ctor; | |
d9377ad5 | 3095 | eltinit = cxx_eval_constant_expression (&new_ctx, init, lval, |
3096 | non_constant_p, overflow_p); | |
3097 | reuse = i == 0; | |
09b42213 | 3098 | } |
3099 | else | |
3100 | { | |
3101 | /* Copying an element. */ | |
3102 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
3103 | (atype, TREE_TYPE (init))); | |
c4970310 | 3104 | eltinit = cp_build_array_ref (input_location, init, idx, complain); |
18bede74 | 3105 | if (!lvalue_p (init)) |
09b42213 | 3106 | eltinit = move (eltinit); |
c4970310 | 3107 | eltinit = force_rvalue (eltinit, complain); |
eb7c25cc | 3108 | eltinit = cxx_eval_constant_expression (&new_ctx, eltinit, lval, |
3109 | non_constant_p, overflow_p); | |
09b42213 | 3110 | } |
f83e6885 | 3111 | if (*non_constant_p && !ctx->quiet) |
cf72f34d | 3112 | break; |
3113 | if (new_ctx.ctor != ctx->ctor) | |
3114 | { | |
3115 | /* We appended this element above; update the value. */ | |
3116 | gcc_assert ((*p)->last().index == idx); | |
3117 | (*p)->last().value = eltinit; | |
3118 | } | |
3119 | else | |
3120 | CONSTRUCTOR_APPEND_ELT (*p, idx, eltinit); | |
d9377ad5 | 3121 | /* Reuse the result of cxx_eval_constant_expression call |
eb7c25cc | 3122 | from the first iteration to all others if it is a constant |
3123 | initializer that doesn't require relocations. */ | |
d9377ad5 | 3124 | if (reuse |
3125 | && max > 1 | |
eb7c25cc | 3126 | && (eltinit == NULL_TREE |
3127 | || (initializer_constant_valid_p (eltinit, TREE_TYPE (eltinit)) | |
3128 | == null_pointer_node))) | |
d9377ad5 | 3129 | { |
3130 | if (new_ctx.ctor != ctx->ctor) | |
3131 | eltinit = new_ctx.ctor; | |
228a2cd8 | 3132 | tree range = build2 (RANGE_EXPR, size_type_node, |
3133 | build_int_cst (size_type_node, 1), | |
3134 | build_int_cst (size_type_node, max - 1)); | |
3135 | CONSTRUCTOR_APPEND_ELT (*p, range, unshare_constructor (eltinit)); | |
d9377ad5 | 3136 | break; |
3137 | } | |
228a2cd8 | 3138 | else if (i == 0) |
3139 | vec_safe_reserve (*p, max); | |
09b42213 | 3140 | } |
3141 | ||
3142 | if (!*non_constant_p) | |
3143 | { | |
cf72f34d | 3144 | init = ctx->ctor; |
165d0d5b | 3145 | CONSTRUCTOR_NO_CLEARING (init) = false; |
09b42213 | 3146 | } |
09b42213 | 3147 | return init; |
3148 | } | |
3149 | ||
3150 | static tree | |
cf72f34d | 3151 | cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3152 | bool lval, |
09b42213 | 3153 | bool *non_constant_p, bool *overflow_p) |
3154 | { | |
3155 | tree atype = TREE_TYPE (t); | |
3156 | tree init = VEC_INIT_EXPR_INIT (t); | |
cf72f34d | 3157 | tree r = cxx_eval_vec_init_1 (ctx, atype, init, |
09b42213 | 3158 | VEC_INIT_EXPR_VALUE_INIT (t), |
1227ba74 | 3159 | lval, non_constant_p, overflow_p); |
09b42213 | 3160 | if (*non_constant_p) |
3161 | return t; | |
3162 | else | |
3163 | return r; | |
3164 | } | |
3165 | ||
6b53d686 | 3166 | /* Like same_type_ignoring_top_level_qualifiers_p, but also handle the case |
3167 | where the desired type is an array of unknown bounds because the variable | |
3168 | has had its bounds deduced since the wrapping expression was created. */ | |
3169 | ||
3170 | static bool | |
3171 | same_type_ignoring_tlq_and_bounds_p (tree type1, tree type2) | |
3172 | { | |
3173 | while (TREE_CODE (type1) == ARRAY_TYPE | |
3174 | && TREE_CODE (type2) == ARRAY_TYPE | |
3175 | && (!TYPE_DOMAIN (type1) || !TYPE_DOMAIN (type2))) | |
3176 | { | |
3177 | type1 = TREE_TYPE (type1); | |
3178 | type2 = TREE_TYPE (type2); | |
3179 | } | |
3180 | return same_type_ignoring_top_level_qualifiers_p (type1, type2); | |
3181 | } | |
3182 | ||
09b42213 | 3183 | /* A less strict version of fold_indirect_ref_1, which requires cv-quals to |
3184 | match. We want to be less strict for simple *& folding; if we have a | |
3185 | non-const temporary that we access through a const pointer, that should | |
3186 | work. We handle this here rather than change fold_indirect_ref_1 | |
3187 | because we're dealing with things like ADDR_EXPR of INTEGER_CST which | |
3188 | don't really make sense outside of constant expression evaluation. Also | |
3189 | we want to allow folding to COMPONENT_REF, which could cause trouble | |
3190 | with TBAA in fold_indirect_ref_1. | |
3191 | ||
3192 | Try to keep this function synced with fold_indirect_ref_1. */ | |
3193 | ||
3194 | static tree | |
3195 | cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) | |
3196 | { | |
7d8e655d | 3197 | tree sub = op0; |
3198 | tree subtype; | |
3199 | poly_uint64 const_op01; | |
09b42213 | 3200 | |
09b42213 | 3201 | STRIP_NOPS (sub); |
3202 | subtype = TREE_TYPE (sub); | |
d03fa520 | 3203 | if (!INDIRECT_TYPE_P (subtype)) |
09b42213 | 3204 | return NULL_TREE; |
3205 | ||
3206 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3207 | { | |
3208 | tree op = TREE_OPERAND (sub, 0); | |
3209 | tree optype = TREE_TYPE (op); | |
3210 | ||
3211 | /* *&CONST_DECL -> to the value of the const decl. */ | |
3212 | if (TREE_CODE (op) == CONST_DECL) | |
3213 | return DECL_INITIAL (op); | |
3214 | /* *&p => p; make sure to handle *&"str"[cst] here. */ | |
6b53d686 | 3215 | if (same_type_ignoring_tlq_and_bounds_p (optype, type)) |
09b42213 | 3216 | { |
3217 | tree fop = fold_read_from_constant_string (op); | |
3218 | if (fop) | |
3219 | return fop; | |
3220 | else | |
3221 | return op; | |
3222 | } | |
3223 | /* *(foo *)&fooarray => fooarray[0] */ | |
3224 | else if (TREE_CODE (optype) == ARRAY_TYPE | |
3225 | && (same_type_ignoring_top_level_qualifiers_p | |
3226 | (type, TREE_TYPE (optype)))) | |
3227 | { | |
3228 | tree type_domain = TYPE_DOMAIN (optype); | |
3229 | tree min_val = size_zero_node; | |
3230 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3231 | min_val = TYPE_MIN_VALUE (type_domain); | |
3232 | return build4_loc (loc, ARRAY_REF, type, op, min_val, | |
3233 | NULL_TREE, NULL_TREE); | |
3234 | } | |
3235 | /* *(foo *)&complexfoo => __real__ complexfoo */ | |
3236 | else if (TREE_CODE (optype) == COMPLEX_TYPE | |
3237 | && (same_type_ignoring_top_level_qualifiers_p | |
3238 | (type, TREE_TYPE (optype)))) | |
3239 | return fold_build1_loc (loc, REALPART_EXPR, type, op); | |
3240 | /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3241 | else if (VECTOR_TYPE_P (optype) |
09b42213 | 3242 | && (same_type_ignoring_top_level_qualifiers_p |
3243 | (type, TREE_TYPE (optype)))) | |
3244 | { | |
3245 | tree part_width = TYPE_SIZE (type); | |
3246 | tree index = bitsize_int (0); | |
7d8e655d | 3247 | return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, |
3248 | index); | |
09b42213 | 3249 | } |
3250 | /* Also handle conversion to an empty base class, which | |
3251 | is represented with a NOP_EXPR. */ | |
3252 | else if (is_empty_class (type) | |
3253 | && CLASS_TYPE_P (optype) | |
3254 | && DERIVED_FROM_P (type, optype)) | |
3255 | { | |
3256 | *empty_base = true; | |
3257 | return op; | |
3258 | } | |
3259 | /* *(foo *)&struct_with_foo_field => COMPONENT_REF */ | |
3260 | else if (RECORD_OR_UNION_TYPE_P (optype)) | |
3261 | { | |
3262 | tree field = TYPE_FIELDS (optype); | |
3263 | for (; field; field = DECL_CHAIN (field)) | |
3264 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3265 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3266 | && integer_zerop (byte_position (field)) |
3267 | && (same_type_ignoring_top_level_qualifiers_p | |
3268 | (TREE_TYPE (field), type))) | |
a48667ee | 3269 | return fold_build3 (COMPONENT_REF, type, op, field, NULL_TREE); |
09b42213 | 3270 | } |
3271 | } | |
3272 | else if (TREE_CODE (sub) == POINTER_PLUS_EXPR | |
7d8e655d | 3273 | && poly_int_tree_p (TREE_OPERAND (sub, 1), &const_op01)) |
09b42213 | 3274 | { |
3275 | tree op00 = TREE_OPERAND (sub, 0); | |
3276 | tree op01 = TREE_OPERAND (sub, 1); | |
3277 | ||
3278 | STRIP_NOPS (op00); | |
3279 | if (TREE_CODE (op00) == ADDR_EXPR) | |
3280 | { | |
3281 | tree op00type; | |
3282 | op00 = TREE_OPERAND (op00, 0); | |
3283 | op00type = TREE_TYPE (op00); | |
3284 | ||
3285 | /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */ | |
76249021 | 3286 | if (VECTOR_TYPE_P (op00type) |
7d8e655d | 3287 | && same_type_ignoring_top_level_qualifiers_p |
3288 | (type, TREE_TYPE (op00type)) | |
3289 | /* POINTER_PLUS_EXPR second operand is sizetype, unsigned, | |
3290 | but we want to treat offsets with MSB set as negative. | |
3291 | For the code below negative offsets are invalid and | |
3292 | TYPE_SIZE of the element is something unsigned, so | |
3293 | check whether op01 fits into poly_int64, which implies | |
3294 | it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and | |
3295 | then just use poly_uint64 because we want to treat the | |
3296 | value as unsigned. */ | |
3297 | && tree_fits_poly_int64_p (op01)) | |
09b42213 | 3298 | { |
09b42213 | 3299 | tree part_width = TYPE_SIZE (type); |
7d8e655d | 3300 | poly_uint64 max_offset |
3301 | = (tree_to_uhwi (part_width) / BITS_PER_UNIT | |
3302 | * TYPE_VECTOR_SUBPARTS (op00type)); | |
3303 | if (known_lt (const_op01, max_offset)) | |
3304 | { | |
3305 | tree index = bitsize_int (const_op01 * BITS_PER_UNIT); | |
3306 | return fold_build3_loc (loc, | |
3307 | BIT_FIELD_REF, type, op00, | |
3308 | part_width, index); | |
3309 | } | |
09b42213 | 3310 | } |
3311 | /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ | |
3312 | else if (TREE_CODE (op00type) == COMPLEX_TYPE | |
3313 | && (same_type_ignoring_top_level_qualifiers_p | |
3314 | (type, TREE_TYPE (op00type)))) | |
3315 | { | |
7d8e655d | 3316 | if (known_eq (wi::to_poly_offset (TYPE_SIZE_UNIT (type)), |
3317 | const_op01)) | |
09b42213 | 3318 | return fold_build1_loc (loc, IMAGPART_EXPR, type, op00); |
3319 | } | |
3320 | /* ((foo *)&fooarray)[1] => fooarray[1] */ | |
3321 | else if (TREE_CODE (op00type) == ARRAY_TYPE | |
3322 | && (same_type_ignoring_top_level_qualifiers_p | |
3323 | (type, TREE_TYPE (op00type)))) | |
3324 | { | |
3325 | tree type_domain = TYPE_DOMAIN (op00type); | |
3326 | tree min_val = size_zero_node; | |
3327 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3328 | min_val = TYPE_MIN_VALUE (type_domain); | |
53fa96c0 | 3329 | offset_int off = wi::to_offset (op01); |
3330 | offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type)); | |
3331 | offset_int remainder; | |
3332 | off = wi::divmod_trunc (off, el_sz, SIGNED, &remainder); | |
3333 | if (remainder == 0 && TREE_CODE (min_val) == INTEGER_CST) | |
3334 | { | |
3335 | off = off + wi::to_offset (min_val); | |
3336 | op01 = wide_int_to_tree (sizetype, off); | |
3337 | return build4_loc (loc, ARRAY_REF, type, op00, op01, | |
3338 | NULL_TREE, NULL_TREE); | |
3339 | } | |
09b42213 | 3340 | } |
3341 | /* Also handle conversion to an empty base class, which | |
3342 | is represented with a NOP_EXPR. */ | |
3343 | else if (is_empty_class (type) | |
3344 | && CLASS_TYPE_P (op00type) | |
3345 | && DERIVED_FROM_P (type, op00type)) | |
3346 | { | |
3347 | *empty_base = true; | |
3348 | return op00; | |
3349 | } | |
3350 | /* ((foo *)&struct_with_foo_field)[1] => COMPONENT_REF */ | |
3351 | else if (RECORD_OR_UNION_TYPE_P (op00type)) | |
3352 | { | |
3353 | tree field = TYPE_FIELDS (op00type); | |
3354 | for (; field; field = DECL_CHAIN (field)) | |
3355 | if (TREE_CODE (field) == FIELD_DECL | |
a48667ee | 3356 | && TREE_TYPE (field) != error_mark_node |
09b42213 | 3357 | && tree_int_cst_equal (byte_position (field), op01) |
3358 | && (same_type_ignoring_top_level_qualifiers_p | |
3359 | (TREE_TYPE (field), type))) | |
a48667ee | 3360 | return fold_build3 (COMPONENT_REF, type, op00, |
3361 | field, NULL_TREE); | |
09b42213 | 3362 | } |
3363 | } | |
3364 | } | |
3365 | /* *(foo *)fooarrptr => (*fooarrptr)[0] */ | |
3366 | else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE | |
3367 | && (same_type_ignoring_top_level_qualifiers_p | |
3368 | (type, TREE_TYPE (TREE_TYPE (subtype))))) | |
3369 | { | |
3370 | tree type_domain; | |
3371 | tree min_val = size_zero_node; | |
7d8e655d | 3372 | tree newsub |
3373 | = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL); | |
09b42213 | 3374 | if (newsub) |
3375 | sub = newsub; | |
3376 | else | |
3377 | sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub); | |
3378 | type_domain = TYPE_DOMAIN (TREE_TYPE (sub)); | |
3379 | if (type_domain && TYPE_MIN_VALUE (type_domain)) | |
3380 | min_val = TYPE_MIN_VALUE (type_domain); | |
3381 | return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE, | |
3382 | NULL_TREE); | |
3383 | } | |
3384 | ||
3385 | return NULL_TREE; | |
3386 | } | |
3387 | ||
3388 | static tree | |
cf72f34d | 3389 | cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3390 | bool lval, |
09b42213 | 3391 | bool *non_constant_p, bool *overflow_p) |
3392 | { | |
3393 | tree orig_op0 = TREE_OPERAND (t, 0); | |
09b42213 | 3394 | bool empty_base = false; |
09b42213 | 3395 | |
d2c63826 | 3396 | /* We can handle a MEM_REF like an INDIRECT_REF, if MEM_REF's second |
3397 | operand is an integer-zero. Otherwise reject the MEM_REF for now. */ | |
3398 | ||
3399 | if (TREE_CODE (t) == MEM_REF | |
3400 | && (!TREE_OPERAND (t, 1) || !integer_zerop (TREE_OPERAND (t, 1)))) | |
3401 | { | |
3402 | gcc_assert (ctx->quiet); | |
3403 | *non_constant_p = true; | |
3404 | return t; | |
3405 | } | |
3406 | ||
7e0f3388 | 3407 | /* First try to simplify it directly. */ |
3408 | tree r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), orig_op0, | |
3409 | &empty_base); | |
3410 | if (!r) | |
09b42213 | 3411 | { |
7e0f3388 | 3412 | /* If that didn't work, evaluate the operand first. */ |
3413 | tree op0 = cxx_eval_constant_expression (ctx, orig_op0, | |
3414 | /*lval*/false, non_constant_p, | |
3415 | overflow_p); | |
3416 | /* Don't VERIFY_CONSTANT here. */ | |
3417 | if (*non_constant_p) | |
3418 | return t; | |
3419 | ||
cb768824 | 3420 | if (!lval && integer_zerop (op0)) |
3421 | { | |
3422 | if (!ctx->quiet) | |
3423 | error ("dereferencing a null pointer"); | |
3424 | *non_constant_p = true; | |
3425 | return t; | |
3426 | } | |
3427 | ||
7e0f3388 | 3428 | r = cxx_fold_indirect_ref (EXPR_LOCATION (t), TREE_TYPE (t), op0, |
3429 | &empty_base); | |
3430 | if (r == NULL_TREE) | |
09b42213 | 3431 | { |
3432 | /* We couldn't fold to a constant value. Make sure it's not | |
3433 | something we should have been able to fold. */ | |
7e0f3388 | 3434 | tree sub = op0; |
3435 | STRIP_NOPS (sub); | |
3436 | if (TREE_CODE (sub) == ADDR_EXPR) | |
3437 | { | |
3438 | gcc_assert (!same_type_ignoring_top_level_qualifiers_p | |
3439 | (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t))); | |
3440 | /* DR 1188 says we don't have to deal with this. */ | |
3441 | if (!ctx->quiet) | |
3442 | error ("accessing value of %qE through a %qT glvalue in a " | |
3443 | "constant expression", build_fold_indirect_ref (sub), | |
3444 | TREE_TYPE (t)); | |
3445 | *non_constant_p = true; | |
3446 | return t; | |
3447 | } | |
3448 | ||
3449 | if (lval && op0 != orig_op0) | |
3450 | return build1 (INDIRECT_REF, TREE_TYPE (t), op0); | |
3451 | if (!lval) | |
3452 | VERIFY_CONSTANT (t); | |
09b42213 | 3453 | return t; |
3454 | } | |
3455 | } | |
3456 | ||
7e0f3388 | 3457 | r = cxx_eval_constant_expression (ctx, r, |
3458 | lval, non_constant_p, overflow_p); | |
3459 | if (*non_constant_p) | |
3460 | return t; | |
3461 | ||
ce4ffd9e | 3462 | /* If we're pulling out the value of an empty base, just return an empty |
09b42213 | 3463 | CONSTRUCTOR. */ |
1227ba74 | 3464 | if (empty_base && !lval) |
09b42213 | 3465 | { |
09b42213 | 3466 | r = build_constructor (TREE_TYPE (t), NULL); |
3467 | TREE_CONSTANT (r) = true; | |
3468 | } | |
3469 | ||
09b42213 | 3470 | return r; |
3471 | } | |
3472 | ||
3473 | /* Complain about R, a VAR_DECL, not being usable in a constant expression. | |
3474 | Shared between potential_constant_expression and | |
3475 | cxx_eval_constant_expression. */ | |
3476 | ||
3477 | static void | |
3478 | non_const_var_error (tree r) | |
3479 | { | |
3480 | tree type = TREE_TYPE (r); | |
3481 | error ("the value of %qD is not usable in a constant " | |
3482 | "expression", r); | |
3483 | /* Avoid error cascade. */ | |
3484 | if (DECL_INITIAL (r) == error_mark_node) | |
3485 | return; | |
3486 | if (DECL_DECLARED_CONSTEXPR_P (r)) | |
3487 | inform (DECL_SOURCE_LOCATION (r), | |
3488 | "%qD used in its own initializer", r); | |
3489 | else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) | |
3490 | { | |
3491 | if (!CP_TYPE_CONST_P (type)) | |
3492 | inform (DECL_SOURCE_LOCATION (r), | |
3493 | "%q#D is not const", r); | |
3494 | else if (CP_TYPE_VOLATILE_P (type)) | |
3495 | inform (DECL_SOURCE_LOCATION (r), | |
3496 | "%q#D is volatile", r); | |
3497 | else if (!DECL_INITIAL (r) | |
c8e3e744 | 3498 | || !TREE_CONSTANT (DECL_INITIAL (r)) |
3499 | || !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (r)) | |
09b42213 | 3500 | inform (DECL_SOURCE_LOCATION (r), |
3501 | "%qD was not initialized with a constant " | |
3502 | "expression", r); | |
3503 | else | |
3504 | gcc_unreachable (); | |
3505 | } | |
90ad495b | 3506 | else if (TYPE_REF_P (type)) |
ac6641ca | 3507 | inform (DECL_SOURCE_LOCATION (r), |
3508 | "%qD was not initialized with a constant " | |
3509 | "expression", r); | |
09b42213 | 3510 | else |
3511 | { | |
3512 | if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r)) | |
3513 | inform (DECL_SOURCE_LOCATION (r), | |
3514 | "%qD was not declared %<constexpr%>", r); | |
3515 | else | |
3516 | inform (DECL_SOURCE_LOCATION (r), | |
3517 | "%qD does not have integral or enumeration type", | |
3518 | r); | |
3519 | } | |
3520 | } | |
3521 | ||
3522 | /* Subroutine of cxx_eval_constant_expression. | |
3523 | Like cxx_eval_unary_expression, except for trinary expressions. */ | |
3524 | ||
3525 | static tree | |
cf72f34d | 3526 | cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 3527 | bool lval, |
09b42213 | 3528 | bool *non_constant_p, bool *overflow_p) |
3529 | { | |
3530 | int i; | |
3531 | tree args[3]; | |
3532 | tree val; | |
3533 | ||
3534 | for (i = 0; i < 3; i++) | |
3535 | { | |
cf72f34d | 3536 | args[i] = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, i), |
1227ba74 | 3537 | lval, |
b2a43197 | 3538 | non_constant_p, overflow_p); |
09b42213 | 3539 | VERIFY_CONSTANT (args[i]); |
3540 | } | |
3541 | ||
3542 | val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t), | |
3543 | args[0], args[1], args[2]); | |
3544 | if (val == NULL_TREE) | |
3545 | return t; | |
3546 | VERIFY_CONSTANT (val); | |
3547 | return val; | |
3548 | } | |
3549 | ||
33603066 | 3550 | /* True if T was declared in a function declared to be constexpr, and |
3551 | therefore potentially constant in C++14. */ | |
3552 | ||
09b42213 | 3553 | bool |
3554 | var_in_constexpr_fn (tree t) | |
3555 | { | |
3556 | tree ctx = DECL_CONTEXT (t); | |
33603066 | 3557 | return (ctx && TREE_CODE (ctx) == FUNCTION_DECL |
09b42213 | 3558 | && DECL_DECLARED_CONSTEXPR_P (ctx)); |
3559 | } | |
3560 | ||
33603066 | 3561 | /* True if T was declared in a function that might be constexpr: either a |
3562 | function that was declared constexpr, or a C++17 lambda op(). */ | |
3563 | ||
3564 | bool | |
3565 | var_in_maybe_constexpr_fn (tree t) | |
3566 | { | |
40e2decb | 3567 | if (cxx_dialect >= cxx17 |
33603066 | 3568 | && DECL_FUNCTION_SCOPE_P (t) |
3569 | && LAMBDA_FUNCTION_P (DECL_CONTEXT (t))) | |
3570 | return true; | |
3571 | return var_in_constexpr_fn (t); | |
3572 | } | |
3573 | ||
93312944 | 3574 | /* We're assigning INIT to TARGET. In do_build_copy_constructor and |
3575 | build_over_call we implement trivial copy of a class with tail padding using | |
3576 | assignment of character arrays, which is valid in normal code, but not in | |
3577 | constexpr evaluation. We don't need to worry about clobbering tail padding | |
3578 | in constexpr evaluation, so strip the type punning. */ | |
3579 | ||
3580 | static void | |
3581 | maybe_simplify_trivial_copy (tree &target, tree &init) | |
3582 | { | |
3583 | if (TREE_CODE (target) == MEM_REF | |
3584 | && TREE_CODE (init) == MEM_REF | |
3585 | && TREE_TYPE (target) == TREE_TYPE (init) | |
3586 | && TREE_CODE (TREE_TYPE (target)) == ARRAY_TYPE | |
3587 | && TREE_TYPE (TREE_TYPE (target)) == unsigned_char_type_node) | |
3588 | { | |
3589 | target = build_fold_indirect_ref (TREE_OPERAND (target, 0)); | |
3590 | init = build_fold_indirect_ref (TREE_OPERAND (init, 0)); | |
3591 | } | |
3592 | } | |
3593 | ||
9c96033c | 3594 | /* Evaluate an INIT_EXPR or MODIFY_EXPR. */ |
3595 | ||
3596 | static tree | |
3597 | cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3598 | bool lval, |
9c96033c | 3599 | bool *non_constant_p, bool *overflow_p) |
3600 | { | |
3601 | constexpr_ctx new_ctx = *ctx; | |
3602 | ||
8a36d0ec | 3603 | tree init = TREE_OPERAND (t, 1); |
3604 | if (TREE_CLOBBER_P (init)) | |
3605 | /* Just ignore clobbers. */ | |
3606 | return void_node; | |
3607 | ||
9c96033c | 3608 | /* First we figure out where we're storing to. */ |
3609 | tree target = TREE_OPERAND (t, 0); | |
93312944 | 3610 | |
3611 | maybe_simplify_trivial_copy (target, init); | |
3612 | ||
9db9fc38 | 3613 | tree type = TREE_TYPE (target); |
9c96033c | 3614 | target = cxx_eval_constant_expression (ctx, target, |
f83e6885 | 3615 | true, |
b2a43197 | 3616 | non_constant_p, overflow_p); |
9c96033c | 3617 | if (*non_constant_p) |
3618 | return t; | |
3619 | ||
cf3cefc9 | 3620 | /* cxx_eval_array_reference for lval = true allows references one past |
3621 | end of array, because it does not know if it is just taking address | |
3622 | (which is valid), or actual dereference. Here we know it is | |
3623 | a dereference, so diagnose it here. */ | |
3624 | for (tree probe = target; probe; ) | |
3625 | { | |
3626 | switch (TREE_CODE (probe)) | |
3627 | { | |
3628 | case ARRAY_REF: | |
3629 | tree nelts, ary; | |
3630 | ary = TREE_OPERAND (probe, 0); | |
51f0c7e2 | 3631 | nelts = get_array_or_vector_nelts (ctx, TREE_TYPE (ary), |
3632 | non_constant_p, overflow_p); | |
cf3cefc9 | 3633 | VERIFY_CONSTANT (nelts); |
3634 | gcc_assert (TREE_CODE (nelts) == INTEGER_CST | |
3635 | && TREE_CODE (TREE_OPERAND (probe, 1)) == INTEGER_CST); | |
cb7bca5f | 3636 | if (wi::to_widest (TREE_OPERAND (probe, 1)) == wi::to_widest (nelts)) |
cf3cefc9 | 3637 | { |
3638 | diag_array_subscript (ctx, ary, TREE_OPERAND (probe, 1)); | |
3639 | *non_constant_p = true; | |
3640 | return t; | |
3641 | } | |
3642 | /* FALLTHRU */ | |
3643 | ||
3644 | case BIT_FIELD_REF: | |
3645 | case COMPONENT_REF: | |
3646 | probe = TREE_OPERAND (probe, 0); | |
3647 | continue; | |
3648 | ||
3649 | default: | |
3650 | probe = NULL_TREE; | |
3651 | continue; | |
3652 | } | |
3653 | } | |
3654 | ||
9db9fc38 | 3655 | if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (target), type)) |
3656 | { | |
3657 | /* For initialization of an empty base, the original target will be | |
3658 | *(base*)this, which the above evaluation resolves to the object | |
3659 | argument, which has the derived type rather than the base type. In | |
3660 | this situation, just evaluate the initializer and return, since | |
3661 | there's no actual data to store. */ | |
3662 | gcc_assert (is_empty_class (type)); | |
3663 | return cxx_eval_constant_expression (ctx, init, false, | |
3664 | non_constant_p, overflow_p); | |
3665 | } | |
3666 | ||
9c96033c | 3667 | /* And then find the underlying variable. */ |
3668 | vec<tree,va_gc> *refs = make_tree_vector(); | |
3669 | tree object = NULL_TREE; | |
3670 | for (tree probe = target; object == NULL_TREE; ) | |
3671 | { | |
3672 | switch (TREE_CODE (probe)) | |
3673 | { | |
3674 | case BIT_FIELD_REF: | |
3675 | case COMPONENT_REF: | |
3676 | case ARRAY_REF: | |
3677 | vec_safe_push (refs, TREE_OPERAND (probe, 1)); | |
3678 | vec_safe_push (refs, TREE_TYPE (probe)); | |
3679 | probe = TREE_OPERAND (probe, 0); | |
3680 | break; | |
3681 | ||
3682 | default: | |
3683 | object = probe; | |
9c96033c | 3684 | } |
3685 | } | |
3686 | ||
3687 | /* And then find/build up our initializer for the path to the subobject | |
3688 | we're initializing. */ | |
6fe83e54 | 3689 | tree *valp; |
43b7271d | 3690 | if (object == ctx->object && VAR_P (object) |
3691 | && DECL_NAME (object) && ctx->call == NULL) | |
3692 | /* The variable we're building up an aggregate initializer for is outside | |
3693 | the constant-expression, so don't evaluate the store. We check | |
3694 | DECL_NAME to handle TARGET_EXPR temporaries, which are fair game. */ | |
3695 | valp = NULL; | |
3696 | else if (DECL_P (object)) | |
6fe83e54 | 3697 | valp = ctx->values->get (object); |
3698 | else | |
3699 | valp = NULL; | |
9c96033c | 3700 | if (!valp) |
3701 | { | |
3702 | /* A constant-expression cannot modify objects from outside the | |
3703 | constant-expression. */ | |
f83e6885 | 3704 | if (!ctx->quiet) |
ea034e2c | 3705 | error ("modification of %qE is not a constant expression", object); |
9c96033c | 3706 | *non_constant_p = true; |
3707 | return t; | |
3708 | } | |
9db9fc38 | 3709 | type = TREE_TYPE (object); |
a02b42fe | 3710 | bool no_zero_init = true; |
58b0f9ce | 3711 | |
3712 | vec<tree,va_gc> *ctors = make_tree_vector (); | |
9c96033c | 3713 | while (!refs->is_empty()) |
3714 | { | |
3715 | if (*valp == NULL_TREE) | |
3716 | { | |
3717 | *valp = build_constructor (type, NULL); | |
165d0d5b | 3718 | CONSTRUCTOR_NO_CLEARING (*valp) = no_zero_init; |
9c96033c | 3719 | } |
92fe8840 | 3720 | else if (TREE_CODE (*valp) == STRING_CST) |
3721 | { | |
3722 | /* An array was initialized with a string constant, and now | |
3723 | we're writing into one of its elements. Explode the | |
3724 | single initialization into a set of element | |
3725 | initializations. */ | |
3726 | gcc_assert (TREE_CODE (type) == ARRAY_TYPE); | |
3727 | ||
3728 | tree string = *valp; | |
3729 | tree elt_type = TREE_TYPE (type); | |
3730 | unsigned chars_per_elt = (TYPE_PRECISION (elt_type) | |
3731 | / TYPE_PRECISION (char_type_node)); | |
3732 | unsigned num_elts = TREE_STRING_LENGTH (string) / chars_per_elt; | |
3733 | tree ary_ctor = build_constructor (type, NULL); | |
3734 | ||
3735 | vec_safe_reserve (CONSTRUCTOR_ELTS (ary_ctor), num_elts); | |
3736 | for (unsigned ix = 0; ix != num_elts; ix++) | |
3737 | { | |
3738 | constructor_elt elt = | |
3739 | { | |
3740 | build_int_cst (size_type_node, ix), | |
3741 | extract_string_elt (string, chars_per_elt, ix) | |
3742 | }; | |
3743 | CONSTRUCTOR_ELTS (ary_ctor)->quick_push (elt); | |
3744 | } | |
3745 | ||
3746 | *valp = ary_ctor; | |
3747 | } | |
3748 | ||
a02b42fe | 3749 | /* If the value of object is already zero-initialized, any new ctors for |
3750 | subobjects will also be zero-initialized. */ | |
165d0d5b | 3751 | no_zero_init = CONSTRUCTOR_NO_CLEARING (*valp); |
9c96033c | 3752 | |
58b0f9ce | 3753 | vec_safe_push (ctors, *valp); |
3754 | ||
7963b19d | 3755 | enum tree_code code = TREE_CODE (type); |
9c96033c | 3756 | type = refs->pop(); |
7963b19d | 3757 | tree index = refs->pop(); |
9c96033c | 3758 | |
9c96033c | 3759 | constructor_elt *cep = NULL; |
7963b19d | 3760 | if (code == ARRAY_TYPE) |
3761 | { | |
3762 | HOST_WIDE_INT i | |
3763 | = find_array_ctor_elt (*valp, index, /*insert*/true); | |
3764 | gcc_assert (i >= 0); | |
3765 | cep = CONSTRUCTOR_ELT (*valp, i); | |
3766 | gcc_assert (TREE_CODE (cep->index) != RANGE_EXPR); | |
3767 | } | |
3768 | else | |
3769 | { | |
3770 | gcc_assert (TREE_CODE (index) == FIELD_DECL); | |
13ee2de7 | 3771 | |
3772 | /* We must keep the CONSTRUCTOR's ELTS in FIELD order. | |
3773 | Usually we meet initializers in that order, but it is | |
3774 | possible for base types to be placed not in program | |
3775 | order. */ | |
3776 | tree fields = TYPE_FIELDS (DECL_CONTEXT (index)); | |
3777 | unsigned HOST_WIDE_INT idx; | |
3778 | ||
ef782365 | 3779 | if (code == UNION_TYPE && CONSTRUCTOR_NELTS (*valp) |
3780 | && CONSTRUCTOR_ELT (*valp, 0)->index != index) | |
3781 | /* Changing active member. */ | |
3782 | vec_safe_truncate (CONSTRUCTOR_ELTS (*valp), 0); | |
3783 | ||
13ee2de7 | 3784 | for (idx = 0; |
7963b19d | 3785 | vec_safe_iterate (CONSTRUCTOR_ELTS (*valp), idx, &cep); |
13ee2de7 | 3786 | idx++, fields = DECL_CHAIN (fields)) |
7963b19d | 3787 | { |
13ee2de7 | 3788 | if (index == cep->index) |
3789 | goto found; | |
3790 | ||
3791 | /* The field we're initializing must be on the field | |
3792 | list. Look to see if it is present before the | |
3793 | field the current ELT initializes. */ | |
3794 | for (; fields != cep->index; fields = DECL_CHAIN (fields)) | |
3795 | if (index == fields) | |
3796 | goto insert; | |
7963b19d | 3797 | } |
13ee2de7 | 3798 | |
3799 | /* We fell off the end of the CONSTRUCTOR, so insert a new | |
3800 | entry at the end. */ | |
3801 | insert: | |
3802 | { | |
3803 | constructor_elt ce = { index, NULL_TREE }; | |
3804 | ||
3805 | vec_safe_insert (CONSTRUCTOR_ELTS (*valp), idx, ce); | |
3806 | cep = CONSTRUCTOR_ELT (*valp, idx); | |
3807 | } | |
3808 | found:; | |
7963b19d | 3809 | } |
9c96033c | 3810 | valp = &cep->value; |
3811 | } | |
3812 | release_tree_vector (refs); | |
3813 | ||
469dc5a6 | 3814 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) |
9c96033c | 3815 | { |
3816 | /* Create a new CONSTRUCTOR in case evaluation of the initializer | |
3817 | wants to modify it. */ | |
469dc5a6 | 3818 | if (*valp == NULL_TREE) |
6cded085 | 3819 | { |
6993e708 | 3820 | *valp = build_constructor (type, NULL); |
165d0d5b | 3821 | CONSTRUCTOR_NO_CLEARING (*valp) = no_zero_init; |
6cded085 | 3822 | } |
6993e708 | 3823 | else if (TREE_CODE (*valp) == PTRMEM_CST) |
3824 | *valp = cplus_expand_constant (*valp); | |
3825 | new_ctx.ctor = *valp; | |
9c96033c | 3826 | new_ctx.object = target; |
3827 | } | |
3828 | ||
8a36d0ec | 3829 | init = cxx_eval_constant_expression (&new_ctx, init, false, |
3830 | non_constant_p, overflow_p); | |
7b9f713d | 3831 | /* Don't share a CONSTRUCTOR that might be changed later. */ |
e283bb4f | 3832 | init = unshare_constructor (init); |
9c96033c | 3833 | if (target == object) |
5579a199 | 3834 | /* The hash table might have moved since the get earlier. */ |
3835 | valp = ctx->values->get (object); | |
3836 | ||
3837 | if (TREE_CODE (init) == CONSTRUCTOR) | |
469dc5a6 | 3838 | { |
5579a199 | 3839 | /* An outer ctx->ctor might be pointing to *valp, so replace |
3840 | its contents. */ | |
3841 | CONSTRUCTOR_ELTS (*valp) = CONSTRUCTOR_ELTS (init); | |
3842 | TREE_CONSTANT (*valp) = TREE_CONSTANT (init); | |
3843 | TREE_SIDE_EFFECTS (*valp) = TREE_SIDE_EFFECTS (init); | |
165d0d5b | 3844 | CONSTRUCTOR_NO_CLEARING (*valp) |
3845 | = CONSTRUCTOR_NO_CLEARING (init); | |
469dc5a6 | 3846 | } |
9c96033c | 3847 | else |
5579a199 | 3848 | *valp = init; |
58b0f9ce | 3849 | |
5579a199 | 3850 | /* Update TREE_CONSTANT and TREE_SIDE_EFFECTS on enclosing |
3851 | CONSTRUCTORs, if any. */ | |
3852 | tree elt; | |
3853 | unsigned i; | |
3854 | bool c = TREE_CONSTANT (init); | |
3855 | bool s = TREE_SIDE_EFFECTS (init); | |
3856 | if (!c || s) | |
3857 | FOR_EACH_VEC_SAFE_ELT (ctors, i, elt) | |
3858 | { | |
3859 | if (!c) | |
3860 | TREE_CONSTANT (elt) = false; | |
3861 | if (s) | |
3862 | TREE_SIDE_EFFECTS (elt) = true; | |
3863 | } | |
58b0f9ce | 3864 | release_tree_vector (ctors); |
9c96033c | 3865 | |
3866 | if (*non_constant_p) | |
3867 | return t; | |
1227ba74 | 3868 | else if (lval) |
9c96033c | 3869 | return target; |
3870 | else | |
dfac7dd2 | 3871 | return init; |
9c96033c | 3872 | } |
3873 | ||
3874 | /* Evaluate a ++ or -- expression. */ | |
3875 | ||
3876 | static tree | |
3877 | cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, | |
1227ba74 | 3878 | bool lval, |
9c96033c | 3879 | bool *non_constant_p, bool *overflow_p) |
3880 | { | |
3881 | enum tree_code code = TREE_CODE (t); | |
3882 | tree type = TREE_TYPE (t); | |
3883 | tree op = TREE_OPERAND (t, 0); | |
3884 | tree offset = TREE_OPERAND (t, 1); | |
3885 | gcc_assert (TREE_CONSTANT (offset)); | |
3886 | ||
3887 | /* The operand as an lvalue. */ | |
f83e6885 | 3888 | op = cxx_eval_constant_expression (ctx, op, true, |
b2a43197 | 3889 | non_constant_p, overflow_p); |
9c96033c | 3890 | |
3891 | /* The operand as an rvalue. */ | |
c017458d | 3892 | tree val |
3893 | = cxx_eval_constant_expression (ctx, op, false, | |
3894 | non_constant_p, overflow_p); | |
35f2c28f | 3895 | /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
3896 | a local array in a constexpr function. */ | |
d03fa520 | 3897 | bool ptr = INDIRECT_TYPE_P (TREE_TYPE (val)); |
35f2c28f | 3898 | if (!ptr) |
3899 | VERIFY_CONSTANT (val); | |
9c96033c | 3900 | |
3901 | /* The modified value. */ | |
3902 | bool inc = (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR); | |
c8a8f7ad | 3903 | tree mod; |
d03fa520 | 3904 | if (INDIRECT_TYPE_P (type)) |
c8a8f7ad | 3905 | { |
3906 | /* The middle end requires pointers to use POINTER_PLUS_EXPR. */ | |
3907 | offset = convert_to_ptrofftype (offset); | |
3908 | if (!inc) | |
3909 | offset = fold_build1 (NEGATE_EXPR, TREE_TYPE (offset), offset); | |
3910 | mod = fold_build2 (POINTER_PLUS_EXPR, type, val, offset); | |
3911 | } | |
3912 | else | |
3913 | mod = fold_build2 (inc ? PLUS_EXPR : MINUS_EXPR, type, val, offset); | |
35f2c28f | 3914 | if (!ptr) |
3915 | VERIFY_CONSTANT (mod); | |
9c96033c | 3916 | |
3917 | /* Storing the modified value. */ | |
3918 | tree store = build2 (MODIFY_EXPR, type, op, mod); | |
f83e6885 | 3919 | cxx_eval_constant_expression (ctx, store, |
b2a43197 | 3920 | true, non_constant_p, overflow_p); |
9c96033c | 3921 | |
3922 | /* And the value of the expression. */ | |
3923 | if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) | |
3924 | { | |
3925 | /* Prefix ops are lvalues. */ | |
1227ba74 | 3926 | if (lval) |
9c96033c | 3927 | return op; |
3928 | else | |
3929 | /* But we optimize when the caller wants an rvalue. */ | |
3930 | return mod; | |
3931 | } | |
3932 | else | |
3933 | /* Postfix ops are rvalues. */ | |
3934 | return val; | |
3935 | } | |
3936 | ||
00f21715 | 3937 | /* Predicates for the meaning of *jump_target. */ |
3938 | ||
3939 | static bool | |
3940 | returns (tree *jump_target) | |
3941 | { | |
3942 | return *jump_target | |
d29e4e8c | 3943 | && (TREE_CODE (*jump_target) == RETURN_EXPR |
3944 | || (TREE_CODE (*jump_target) == LABEL_DECL | |
3945 | && LABEL_DECL_CDTOR (*jump_target))); | |
00f21715 | 3946 | } |
3947 | ||
3948 | static bool | |
3949 | breaks (tree *jump_target) | |
3950 | { | |
3951 | return *jump_target | |
cf03ba19 | 3952 | && ((TREE_CODE (*jump_target) == LABEL_DECL |
3953 | && LABEL_DECL_BREAK (*jump_target)) | |
32fee334 | 3954 | || TREE_CODE (*jump_target) == BREAK_STMT |
cf03ba19 | 3955 | || TREE_CODE (*jump_target) == EXIT_EXPR); |
00f21715 | 3956 | } |
3957 | ||
3958 | static bool | |
3959 | continues (tree *jump_target) | |
3960 | { | |
3961 | return *jump_target | |
32fee334 | 3962 | && ((TREE_CODE (*jump_target) == LABEL_DECL |
3963 | && LABEL_DECL_CONTINUE (*jump_target)) | |
3964 | || TREE_CODE (*jump_target) == CONTINUE_STMT); | |
3965 | ||
00f21715 | 3966 | } |
3967 | ||
3968 | static bool | |
3969 | switches (tree *jump_target) | |
3970 | { | |
3971 | return *jump_target | |
3972 | && TREE_CODE (*jump_target) == INTEGER_CST; | |
3973 | } | |
3974 | ||
3975 | /* Subroutine of cxx_eval_statement_list. Determine whether the statement | |
2a2770c6 | 3976 | STMT matches *jump_target. If we're looking for a case label and we see |
3977 | the default label, note it in ctx->css_state. */ | |
00f21715 | 3978 | |
3979 | static bool | |
2a2770c6 | 3980 | label_matches (const constexpr_ctx *ctx, tree *jump_target, tree stmt) |
00f21715 | 3981 | { |
00f21715 | 3982 | switch (TREE_CODE (*jump_target)) |
3983 | { | |
3984 | case LABEL_DECL: | |
3985 | if (TREE_CODE (stmt) == LABEL_EXPR | |
3986 | && LABEL_EXPR_LABEL (stmt) == *jump_target) | |
3987 | return true; | |
3988 | break; | |
3989 | ||
3990 | case INTEGER_CST: | |
3991 | if (TREE_CODE (stmt) == CASE_LABEL_EXPR) | |
3992 | { | |
2a2770c6 | 3993 | gcc_assert (ctx->css_state != NULL); |
00f21715 | 3994 | if (!CASE_LOW (stmt)) |
2a2770c6 | 3995 | { |
3996 | /* default: should appear just once in a SWITCH_EXPR | |
3997 | body (excluding nested SWITCH_EXPR). */ | |
3998 | gcc_assert (*ctx->css_state != css_default_seen); | |
3999 | /* When evaluating SWITCH_EXPR body for the second time, | |
4000 | return true for the default: label. */ | |
4001 | if (*ctx->css_state == css_default_processing) | |
4002 | return true; | |
4003 | *ctx->css_state = css_default_seen; | |
4004 | } | |
83c375ba | 4005 | else if (CASE_HIGH (stmt)) |
4006 | { | |
4007 | if (tree_int_cst_le (CASE_LOW (stmt), *jump_target) | |
4008 | && tree_int_cst_le (*jump_target, CASE_HIGH (stmt))) | |
4009 | return true; | |
4010 | } | |
00f21715 | 4011 | else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt))) |
4012 | return true; | |
4013 | } | |
4014 | break; | |
4015 | ||
4016 | default: | |
4017 | gcc_unreachable (); | |
4018 | } | |
4019 | return false; | |
4020 | } | |
4021 | ||
4022 | /* Evaluate a STATEMENT_LIST for side-effects. Handles various jump | |
4023 | semantics, for switch, break, continue, and return. */ | |
4024 | ||
4025 | static tree | |
4026 | cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, | |
00f21715 | 4027 | bool *non_constant_p, bool *overflow_p, |
4028 | tree *jump_target) | |
4029 | { | |
4030 | tree_stmt_iterator i; | |
da7981e0 | 4031 | tree local_target; |
efea7c64 | 4032 | /* In a statement-expression we want to return the last value. |
4033 | For empty statement expression return void_node. */ | |
4034 | tree r = void_node; | |
da7981e0 | 4035 | if (!jump_target) |
4036 | { | |
4037 | local_target = NULL_TREE; | |
4038 | jump_target = &local_target; | |
4039 | } | |
00f21715 | 4040 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) |
4041 | { | |
00f21715 | 4042 | tree stmt = tsi_stmt (i); |
ba0f90e4 | 4043 | /* We've found a continue, so skip everything until we reach |
4044 | the label its jumping to. */ | |
4045 | if (continues (jump_target)) | |
4046 | { | |
4047 | if (label_matches (ctx, jump_target, stmt)) | |
4048 | /* Found it. */ | |
4049 | *jump_target = NULL_TREE; | |
4050 | else | |
4051 | continue; | |
4052 | } | |
442c4003 | 4053 | if (TREE_CODE (stmt) == DEBUG_BEGIN_STMT) |
4054 | continue; | |
da7981e0 | 4055 | r = cxx_eval_constant_expression (ctx, stmt, false, |
4056 | non_constant_p, overflow_p, | |
4057 | jump_target); | |
00f21715 | 4058 | if (*non_constant_p) |
4059 | break; | |
4060 | if (returns (jump_target) || breaks (jump_target)) | |
4061 | break; | |
4062 | } | |
da7981e0 | 4063 | return r; |
00f21715 | 4064 | } |
4065 | ||
4066 | /* Evaluate a LOOP_EXPR for side-effects. Handles break and return | |
4067 | semantics; continue semantics are covered by cxx_eval_statement_list. */ | |
4068 | ||
4069 | static tree | |
4070 | cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 4071 | bool *non_constant_p, bool *overflow_p, |
4072 | tree *jump_target) | |
4073 | { | |
2631cb67 | 4074 | constexpr_ctx new_ctx = *ctx; |
4075 | ||
00f21715 | 4076 | tree body = TREE_OPERAND (t, 0); |
21483ab7 | 4077 | int count = 0; |
5370eb8d | 4078 | do |
00f21715 | 4079 | { |
2631cb67 | 4080 | hash_set<tree> save_exprs; |
4081 | new_ctx.save_exprs = &save_exprs; | |
4082 | ||
cf03ba19 | 4083 | cxx_eval_constant_expression (&new_ctx, body, /*lval*/false, |
4084 | non_constant_p, overflow_p, jump_target); | |
2631cb67 | 4085 | |
4086 | /* Forget saved values of SAVE_EXPRs. */ | |
4087 | for (hash_set<tree>::iterator iter = save_exprs.begin(); | |
4088 | iter != save_exprs.end(); ++iter) | |
4089 | new_ctx.values->remove (*iter); | |
21483ab7 | 4090 | if (++count >= constexpr_loop_limit) |
4091 | { | |
4092 | if (!ctx->quiet) | |
d3a3cfb8 | 4093 | error_at (cp_expr_loc_or_loc (t, input_location), |
5967b28b | 4094 | "%<constexpr%> loop iteration count exceeds limit of %d " |
21483ab7 | 4095 | "(use -fconstexpr-loop-limit= to increase the limit)", |
4096 | constexpr_loop_limit); | |
4097 | *non_constant_p = true; | |
4098 | break; | |
4099 | } | |
00f21715 | 4100 | } |
2a2770c6 | 4101 | while (!returns (jump_target) |
4102 | && !breaks (jump_target) | |
4103 | && !switches (jump_target) | |
4104 | && !*non_constant_p); | |
5370eb8d | 4105 | |
00f21715 | 4106 | if (breaks (jump_target)) |
4107 | *jump_target = NULL_TREE; | |
2631cb67 | 4108 | |
00f21715 | 4109 | return NULL_TREE; |
4110 | } | |
4111 | ||
4112 | /* Evaluate a SWITCH_EXPR for side-effects. Handles switch and break jump | |
4113 | semantics. */ | |
4114 | ||
4115 | static tree | |
4116 | cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, | |
00f21715 | 4117 | bool *non_constant_p, bool *overflow_p, |
4118 | tree *jump_target) | |
4119 | { | |
4120 | tree cond = TREE_OPERAND (t, 0); | |
f83e6885 | 4121 | cond = cxx_eval_constant_expression (ctx, cond, false, |
b2a43197 | 4122 | non_constant_p, overflow_p); |
00f21715 | 4123 | VERIFY_CONSTANT (cond); |
4124 | *jump_target = cond; | |
4125 | ||
4126 | tree body = TREE_OPERAND (t, 1); | |
2a2770c6 | 4127 | constexpr_ctx new_ctx = *ctx; |
4128 | constexpr_switch_state css = css_default_not_seen; | |
4129 | new_ctx.css_state = &css; | |
4130 | cxx_eval_constant_expression (&new_ctx, body, false, | |
4131 | non_constant_p, overflow_p, jump_target); | |
4132 | if (switches (jump_target) && css == css_default_seen) | |
4133 | { | |
4134 | /* If the SWITCH_EXPR body has default: label, process it once again, | |
4135 | this time instructing label_matches to return true for default: | |
4136 | label on switches (jump_target). */ | |
4137 | css = css_default_processing; | |
4138 | cxx_eval_constant_expression (&new_ctx, body, false, | |
4139 | non_constant_p, overflow_p, jump_target); | |
4140 | } | |
00f21715 | 4141 | if (breaks (jump_target) || switches (jump_target)) |
4142 | *jump_target = NULL_TREE; | |
4143 | return NULL_TREE; | |
4144 | } | |
4145 | ||
85de9604 | 4146 | /* Find the object of TYPE under initialization in CTX. */ |
4147 | ||
4148 | static tree | |
4149 | lookup_placeholder (const constexpr_ctx *ctx, bool lval, tree type) | |
4150 | { | |
def8e41f | 4151 | if (!ctx) |
85de9604 | 4152 | return NULL_TREE; |
4153 | ||
4154 | /* We could use ctx->object unconditionally, but using ctx->ctor when we | |
4155 | can is a minor optimization. */ | |
def8e41f | 4156 | if (!lval && ctx->ctor && same_type_p (TREE_TYPE (ctx->ctor), type)) |
85de9604 | 4157 | return ctx->ctor; |
4158 | ||
def8e41f | 4159 | if (!ctx->object) |
4160 | return NULL_TREE; | |
4161 | ||
85de9604 | 4162 | /* Since an object cannot have a field of its own type, we can search outward |
4163 | from ctx->object to find the unique containing object of TYPE. */ | |
4164 | tree ob = ctx->object; | |
4165 | while (ob) | |
4166 | { | |
4167 | if (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (ob), type)) | |
4168 | break; | |
4169 | if (handled_component_p (ob)) | |
4170 | ob = TREE_OPERAND (ob, 0); | |
4171 | else | |
4172 | ob = NULL_TREE; | |
4173 | } | |
4174 | ||
4175 | return ob; | |
4176 | } | |
4177 | ||
09b42213 | 4178 | /* Attempt to reduce the expression T to a constant value. |
4179 | On failure, issue diagnostic and return error_mark_node. */ | |
4180 | /* FIXME unify with c_fully_fold */ | |
9c96033c | 4181 | /* FIXME overflow_p is too global */ |
09b42213 | 4182 | |
4183 | static tree | |
cf72f34d | 4184 | cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, |
1227ba74 | 4185 | bool lval, |
00f21715 | 4186 | bool *non_constant_p, bool *overflow_p, |
32fee334 | 4187 | tree *jump_target /* = NULL */) |
09b42213 | 4188 | { |
cf72f34d | 4189 | constexpr_ctx new_ctx; |
09b42213 | 4190 | tree r = t; |
4191 | ||
2a2770c6 | 4192 | if (jump_target && *jump_target) |
4193 | { | |
4194 | /* If we are jumping, ignore all statements/expressions except those | |
4195 | that could have LABEL_EXPR or CASE_LABEL_EXPR in their bodies. */ | |
4196 | switch (TREE_CODE (t)) | |
4197 | { | |
4198 | case BIND_EXPR: | |
4199 | case STATEMENT_LIST: | |
4200 | case LOOP_EXPR: | |
4201 | case COND_EXPR: | |
4202 | break; | |
4203 | case LABEL_EXPR: | |
4204 | case CASE_LABEL_EXPR: | |
4205 | if (label_matches (ctx, jump_target, t)) | |
4206 | /* Found it. */ | |
4207 | *jump_target = NULL_TREE; | |
4208 | return NULL_TREE; | |
4209 | default: | |
4210 | return NULL_TREE; | |
4211 | } | |
4212 | } | |
32fee334 | 4213 | if (error_operand_p (t)) |
09b42213 | 4214 | { |
4215 | *non_constant_p = true; | |
4216 | return t; | |
4217 | } | |
4218 | if (CONSTANT_CLASS_P (t)) | |
4219 | { | |
c4fa85c9 | 4220 | if (TREE_OVERFLOW (t)) |
4221 | { | |
4222 | if (!ctx->quiet) | |
4223 | permerror (input_location, "overflow in constant expression"); | |
4224 | if (!flag_permissive || ctx->quiet) | |
4225 | *overflow_p = true; | |
4226 | } | |
cb768824 | 4227 | |
4228 | if (TREE_CODE (t) == INTEGER_CST | |
90ad495b | 4229 | && TYPE_PTR_P (TREE_TYPE (t)) |
cb768824 | 4230 | && !integer_zerop (t)) |
4231 | { | |
4232 | if (!ctx->quiet) | |
4233 | error ("value %qE of type %qT is not a constant expression", | |
4234 | t, TREE_TYPE (t)); | |
4235 | *non_constant_p = true; | |
4236 | } | |
4237 | ||
09b42213 | 4238 | return t; |
4239 | } | |
09b42213 | 4240 | |
cb768824 | 4241 | tree_code tcode = TREE_CODE (t); |
4242 | switch (tcode) | |
09b42213 | 4243 | { |
9c96033c | 4244 | case RESULT_DECL: |
1227ba74 | 4245 | if (lval) |
9c96033c | 4246 | return t; |
4247 | /* We ask for an rvalue for the RESULT_DECL when indirecting | |
92a9c89e | 4248 | through an invisible reference, or in named return value |
4249 | optimization. */ | |
8ea8d065 | 4250 | if (tree *p = ctx->values->get (t)) |
4251 | return *p; | |
4252 | else | |
4253 | { | |
4254 | if (!ctx->quiet) | |
4255 | error ("%qE is not a constant expression", t); | |
4256 | *non_constant_p = true; | |
4257 | } | |
4258 | break; | |
9c96033c | 4259 | |
09b42213 | 4260 | case VAR_DECL: |
9c8aeb66 | 4261 | if (DECL_HAS_VALUE_EXPR_P (t)) |
33603066 | 4262 | return cxx_eval_constant_expression (ctx, DECL_VALUE_EXPR (t), |
4263 | lval, non_constant_p, overflow_p); | |
e3533433 | 4264 | /* fall through */ |
8b2b2f24 | 4265 | case CONST_DECL: |
4266 | /* We used to not check lval for CONST_DECL, but darwin.c uses | |
4267 | CONST_DECL for aggregate constants. */ | |
1227ba74 | 4268 | if (lval) |
09b42213 | 4269 | return t; |
bb6e576c | 4270 | /* is_really_empty_class doesn't take into account _vptr, so initializing |
4271 | otherwise empty class with { } would overwrite the initializer that | |
4272 | initialize_vtable created for us. */ | |
594cc00c | 4273 | if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
bb6e576c | 4274 | && !TYPE_POLYMORPHIC_P (TREE_TYPE (t)) |
594cc00c | 4275 | && is_really_empty_class (TREE_TYPE (t))) |
c7282bf2 | 4276 | { |
4277 | /* If the class is empty, we aren't actually loading anything. */ | |
4278 | r = build_constructor (TREE_TYPE (t), NULL); | |
4279 | TREE_CONSTANT (r) = true; | |
4280 | } | |
4281 | else if (ctx->strict) | |
2055d27a | 4282 | r = decl_really_constant_value (t); |
4283 | else | |
4284 | r = decl_constant_value (t); | |
09b42213 | 4285 | if (TREE_CODE (r) == TARGET_EXPR |
4286 | && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR) | |
4287 | r = TARGET_EXPR_INITIAL (r); | |
f4ae4202 | 4288 | if (VAR_P (r)) |
cf72f34d | 4289 | if (tree *p = ctx->values->get (r)) |
a143e277 | 4290 | if (*p != NULL_TREE) |
4291 | r = *p; | |
09b42213 | 4292 | if (DECL_P (r)) |
4293 | { | |
f83e6885 | 4294 | if (!ctx->quiet) |
09b42213 | 4295 | non_const_var_error (r); |
4296 | *non_constant_p = true; | |
4297 | } | |
4298 | break; | |
4299 | ||
90567983 | 4300 | case DEBUG_BEGIN_STMT: |
4301 | /* ??? It might be nice to retain this information somehow, so | |
4302 | as to be able to step into a constexpr function call. */ | |
4303 | /* Fall through. */ | |
4304 | ||
09b42213 | 4305 | case FUNCTION_DECL: |
4306 | case TEMPLATE_DECL: | |
4307 | case LABEL_DECL: | |
00f21715 | 4308 | case LABEL_EXPR: |
4309 | case CASE_LABEL_EXPR: | |
2a2770c6 | 4310 | case PREDICT_EXPR: |
09b42213 | 4311 | return t; |
4312 | ||
4313 | case PARM_DECL: | |
90ad495b | 4314 | if (lval && !TYPE_REF_P (TREE_TYPE (t))) |
9c96033c | 4315 | /* glvalue use. */; |
4316 | else if (tree *p = ctx->values->get (r)) | |
4317 | r = *p; | |
1227ba74 | 4318 | else if (lval) |
09b42213 | 4319 | /* Defer in case this is only used for its type. */; |
90ad495b | 4320 | else if (TYPE_REF_P (TREE_TYPE (t))) |
1eb418cc | 4321 | /* Defer, there's no lvalue->rvalue conversion. */; |
53d2f3de | 4322 | else if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
4323 | && is_really_empty_class (TREE_TYPE (t))) | |
a6613de7 | 4324 | { |
4325 | /* If the class is empty, we aren't actually loading anything. */ | |
4326 | r = build_constructor (TREE_TYPE (t), NULL); | |
4327 | TREE_CONSTANT (r) = true; | |
4328 | } | |
09b42213 | 4329 | else |
4330 | { | |
f83e6885 | 4331 | if (!ctx->quiet) |
09b42213 | 4332 | error ("%qE is not a constant expression", t); |
4333 | *non_constant_p = true; | |
4334 | } | |
4335 | break; | |
4336 | ||
4337 | case CALL_EXPR: | |
4338 | case AGGR_INIT_EXPR: | |
1227ba74 | 4339 | r = cxx_eval_call_expression (ctx, t, lval, |
09b42213 | 4340 | non_constant_p, overflow_p); |
4341 | break; | |
4342 | ||
9c96033c | 4343 | case DECL_EXPR: |
4344 | { | |
4345 | r = DECL_EXPR_DECL (t); | |
4346 | if (AGGREGATE_TYPE_P (TREE_TYPE (r)) | |
4347 | || VECTOR_TYPE_P (TREE_TYPE (r))) | |
4348 | { | |
4349 | new_ctx = *ctx; | |
4350 | new_ctx.object = r; | |
4351 | new_ctx.ctor = build_constructor (TREE_TYPE (r), NULL); | |
165d0d5b | 4352 | CONSTRUCTOR_NO_CLEARING (new_ctx.ctor) = true; |
9c96033c | 4353 | new_ctx.values->put (r, new_ctx.ctor); |
4354 | ctx = &new_ctx; | |
4355 | } | |
4356 | ||
4357 | if (tree init = DECL_INITIAL (r)) | |
4358 | { | |
4359 | init = cxx_eval_constant_expression (ctx, init, | |
f83e6885 | 4360 | false, |
b2a43197 | 4361 | non_constant_p, overflow_p); |
5898f0d7 | 4362 | /* Don't share a CONSTRUCTOR that might be changed. */ |
e283bb4f | 4363 | init = unshare_constructor (init); |
9c96033c | 4364 | ctx->values->put (r, init); |
4365 | } | |
4366 | else if (ctx == &new_ctx) | |
4367 | /* We gave it a CONSTRUCTOR above. */; | |
4368 | else | |
4369 | ctx->values->put (r, NULL_TREE); | |
4370 | } | |
4371 | break; | |
4372 | ||
09b42213 | 4373 | case TARGET_EXPR: |
4374 | if (!literal_type_p (TREE_TYPE (t))) | |
4375 | { | |
f83e6885 | 4376 | if (!ctx->quiet) |
09b42213 | 4377 | { |
bc35ef65 | 4378 | auto_diagnostic_group d; |
09b42213 | 4379 | error ("temporary of non-literal type %qT in a " |
4380 | "constant expression", TREE_TYPE (t)); | |
4381 | explain_non_literal_class (TREE_TYPE (t)); | |
4382 | } | |
4383 | *non_constant_p = true; | |
4384 | break; | |
4385 | } | |
cf72f34d | 4386 | if ((AGGREGATE_TYPE_P (TREE_TYPE (t)) || VECTOR_TYPE_P (TREE_TYPE (t)))) |
4387 | { | |
4388 | /* We're being expanded without an explicit target, so start | |
4389 | initializing a new object; expansion with an explicit target | |
4390 | strips the TARGET_EXPR before we get here. */ | |
4391 | new_ctx = *ctx; | |
4392 | new_ctx.ctor = build_constructor (TREE_TYPE (t), NULL); | |
165d0d5b | 4393 | CONSTRUCTOR_NO_CLEARING (new_ctx.ctor) = true; |
cf72f34d | 4394 | new_ctx.object = TARGET_EXPR_SLOT (t); |
4395 | ctx->values->put (new_ctx.object, new_ctx.ctor); | |
4396 | ctx = &new_ctx; | |
4397 | } | |
1227ba74 | 4398 | /* Pass false for 'lval' because this indicates |
09b42213 | 4399 | initialization of a temporary. */ |
cf72f34d | 4400 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
f83e6885 | 4401 | false, |
b2a43197 | 4402 | non_constant_p, overflow_p); |
09b42213 | 4403 | if (!*non_constant_p) |
4404 | /* Adjust the type of the result to the type of the temporary. */ | |
4405 | r = adjust_temp_type (TREE_TYPE (t), r); | |
1227ba74 | 4406 | if (lval) |
1eb418cc | 4407 | { |
4408 | tree slot = TARGET_EXPR_SLOT (t); | |
e283bb4f | 4409 | r = unshare_constructor (r); |
1eb418cc | 4410 | ctx->values->put (slot, r); |
4411 | return slot; | |
4412 | } | |
09b42213 | 4413 | break; |
4414 | ||
9c96033c | 4415 | case INIT_EXPR: |
9c96033c | 4416 | case MODIFY_EXPR: |
2a2770c6 | 4417 | gcc_assert (jump_target == NULL || *jump_target == NULL_TREE); |
1227ba74 | 4418 | r = cxx_eval_store_expression (ctx, t, lval, |
9c96033c | 4419 | non_constant_p, overflow_p); |
4420 | break; | |
4421 | ||
09b42213 | 4422 | case SCOPE_REF: |
cf72f34d | 4423 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
1227ba74 | 4424 | lval, |
b2a43197 | 4425 | non_constant_p, overflow_p); |
09b42213 | 4426 | break; |
4427 | ||
4428 | case RETURN_EXPR: | |
10fb495c | 4429 | if (TREE_OPERAND (t, 0) != NULL_TREE) |
4430 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), | |
4431 | lval, | |
4432 | non_constant_p, overflow_p); | |
2c572f5f | 4433 | if (jump_target) |
4434 | *jump_target = t; | |
4435 | else | |
4436 | { | |
4437 | /* Can happen with ({ return true; }) && false; passed to | |
4438 | maybe_constant_value. There is nothing to jump over in this | |
4439 | case, and the bug will be diagnosed later. */ | |
4440 | gcc_assert (ctx->quiet); | |
4441 | *non_constant_p = true; | |
4442 | } | |
00f21715 | 4443 | break; |
4444 | ||
e0e672a0 | 4445 | case SAVE_EXPR: |
4446 | /* Avoid evaluating a SAVE_EXPR more than once. */ | |
4447 | if (tree *p = ctx->values->get (t)) | |
4448 | r = *p; | |
4449 | else | |
4450 | { | |
c8f6aeb1 | 4451 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), false, |
e0e672a0 | 4452 | non_constant_p, overflow_p); |
4453 | ctx->values->put (t, r); | |
2631cb67 | 4454 | if (ctx->save_exprs) |
4455 | ctx->save_exprs->add (t); | |
e0e672a0 | 4456 | } |
4457 | break; | |
4458 | ||
09b42213 | 4459 | case NON_LVALUE_EXPR: |
4460 | case TRY_CATCH_EXPR: | |
7f67d68c | 4461 | case TRY_BLOCK: |
09b42213 | 4462 | case CLEANUP_POINT_EXPR: |
4463 | case MUST_NOT_THROW_EXPR: | |
9c96033c | 4464 | case EXPR_STMT: |
4465 | case EH_SPEC_BLOCK: | |
cf72f34d | 4466 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
1227ba74 | 4467 | lval, |
00f21715 | 4468 | non_constant_p, overflow_p, |
4469 | jump_target); | |
09b42213 | 4470 | break; |
4471 | ||
7f67d68c | 4472 | case TRY_FINALLY_EXPR: |
4473 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4474 | non_constant_p, overflow_p, | |
4475 | jump_target); | |
4476 | if (!*non_constant_p) | |
4477 | /* Also evaluate the cleanup. */ | |
4478 | cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), true, | |
4479 | non_constant_p, overflow_p, | |
4480 | jump_target); | |
4481 | break; | |
4482 | ||
09b42213 | 4483 | /* These differ from cxx_eval_unary_expression in that this doesn't |
4484 | check for a constant operand or result; an address can be | |
4485 | constant without its operand being, and vice versa. */ | |
d2c63826 | 4486 | case MEM_REF: |
09b42213 | 4487 | case INDIRECT_REF: |
1227ba74 | 4488 | r = cxx_eval_indirect_ref (ctx, t, lval, |
09b42213 | 4489 | non_constant_p, overflow_p); |
4490 | break; | |
4491 | ||
4492 | case ADDR_EXPR: | |
4493 | { | |
4494 | tree oldop = TREE_OPERAND (t, 0); | |
cf72f34d | 4495 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4496 | /*lval*/true, |
b2a43197 | 4497 | non_constant_p, overflow_p); |
09b42213 | 4498 | /* Don't VERIFY_CONSTANT here. */ |
4499 | if (*non_constant_p) | |
4500 | return t; | |
1eb418cc | 4501 | gcc_checking_assert (TREE_CODE (op) != CONSTRUCTOR); |
09b42213 | 4502 | /* This function does more aggressive folding than fold itself. */ |
4503 | r = build_fold_addr_expr_with_type (op, TREE_TYPE (t)); | |
4504 | if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop) | |
4505 | return t; | |
4506 | break; | |
4507 | } | |
4508 | ||
4509 | case REALPART_EXPR: | |
4510 | case IMAGPART_EXPR: | |
6fe424c2 | 4511 | if (lval) |
4512 | { | |
4513 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, | |
4514 | non_constant_p, overflow_p); | |
4515 | if (r == error_mark_node) | |
4516 | ; | |
4517 | else if (r == TREE_OPERAND (t, 0)) | |
4518 | r = t; | |
4519 | else | |
4520 | r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), r); | |
4521 | break; | |
4522 | } | |
4523 | /* FALLTHRU */ | |
09b42213 | 4524 | case CONJ_EXPR: |
4525 | case FIX_TRUNC_EXPR: | |
4526 | case FLOAT_EXPR: | |
4527 | case NEGATE_EXPR: | |
4528 | case ABS_EXPR: | |
19b4138e | 4529 | case ABSU_EXPR: |
09b42213 | 4530 | case BIT_NOT_EXPR: |
4531 | case TRUTH_NOT_EXPR: | |
4532 | case FIXED_CONVERT_EXPR: | |
1227ba74 | 4533 | r = cxx_eval_unary_expression (ctx, t, lval, |
09b42213 | 4534 | non_constant_p, overflow_p); |
4535 | break; | |
4536 | ||
4537 | case SIZEOF_EXPR: | |
d2c63826 | 4538 | r = fold_sizeof_expr (t); |
09b42213 | 4539 | VERIFY_CONSTANT (r); |
4540 | break; | |
4541 | ||
4542 | case COMPOUND_EXPR: | |
4543 | { | |
4544 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
4545 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
4546 | introduced by build_call_a. */ | |
4547 | tree op0 = TREE_OPERAND (t, 0); | |
4548 | tree op1 = TREE_OPERAND (t, 1); | |
4549 | STRIP_NOPS (op1); | |
4550 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
4551 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
f83e6885 | 4552 | r = cxx_eval_constant_expression (ctx, op0, |
1227ba74 | 4553 | lval, non_constant_p, overflow_p, |
00f21715 | 4554 | jump_target); |
09b42213 | 4555 | else |
4556 | { | |
4557 | /* Check that the LHS is constant and then discard it. */ | |
f83e6885 | 4558 | cxx_eval_constant_expression (ctx, op0, |
c8f6aeb1 | 4559 | true, non_constant_p, overflow_p, |
00f21715 | 4560 | jump_target); |
cf03ba19 | 4561 | if (*non_constant_p) |
4562 | return t; | |
09b42213 | 4563 | op1 = TREE_OPERAND (t, 1); |
f83e6885 | 4564 | r = cxx_eval_constant_expression (ctx, op1, |
1227ba74 | 4565 | lval, non_constant_p, overflow_p, |
00f21715 | 4566 | jump_target); |
09b42213 | 4567 | } |
4568 | } | |
4569 | break; | |
4570 | ||
4571 | case POINTER_PLUS_EXPR: | |
57e83b58 | 4572 | case POINTER_DIFF_EXPR: |
09b42213 | 4573 | case PLUS_EXPR: |
4574 | case MINUS_EXPR: | |
4575 | case MULT_EXPR: | |
4576 | case TRUNC_DIV_EXPR: | |
4577 | case CEIL_DIV_EXPR: | |
4578 | case FLOOR_DIV_EXPR: | |
4579 | case ROUND_DIV_EXPR: | |
4580 | case TRUNC_MOD_EXPR: | |
4581 | case CEIL_MOD_EXPR: | |
4582 | case ROUND_MOD_EXPR: | |
4583 | case RDIV_EXPR: | |
4584 | case EXACT_DIV_EXPR: | |
4585 | case MIN_EXPR: | |
4586 | case MAX_EXPR: | |
4587 | case LSHIFT_EXPR: | |
4588 | case RSHIFT_EXPR: | |
4589 | case LROTATE_EXPR: | |
4590 | case RROTATE_EXPR: | |
4591 | case BIT_IOR_EXPR: | |
4592 | case BIT_XOR_EXPR: | |
4593 | case BIT_AND_EXPR: | |
4594 | case TRUTH_XOR_EXPR: | |
4595 | case LT_EXPR: | |
4596 | case LE_EXPR: | |
4597 | case GT_EXPR: | |
4598 | case GE_EXPR: | |
4599 | case EQ_EXPR: | |
4600 | case NE_EXPR: | |
4601 | case UNORDERED_EXPR: | |
4602 | case ORDERED_EXPR: | |
4603 | case UNLT_EXPR: | |
4604 | case UNLE_EXPR: | |
4605 | case UNGT_EXPR: | |
4606 | case UNGE_EXPR: | |
4607 | case UNEQ_EXPR: | |
4608 | case LTGT_EXPR: | |
4609 | case RANGE_EXPR: | |
4610 | case COMPLEX_EXPR: | |
1227ba74 | 4611 | r = cxx_eval_binary_expression (ctx, t, lval, |
09b42213 | 4612 | non_constant_p, overflow_p); |
4613 | break; | |
4614 | ||
4615 | /* fold can introduce non-IF versions of these; still treat them as | |
4616 | short-circuiting. */ | |
4617 | case TRUTH_AND_EXPR: | |
4618 | case TRUTH_ANDIF_EXPR: | |
cf72f34d | 4619 | r = cxx_eval_logical_expression (ctx, t, boolean_false_node, |
09b42213 | 4620 | boolean_true_node, |
1227ba74 | 4621 | lval, |
09b42213 | 4622 | non_constant_p, overflow_p); |
4623 | break; | |
4624 | ||
4625 | case TRUTH_OR_EXPR: | |
4626 | case TRUTH_ORIF_EXPR: | |
cf72f34d | 4627 | r = cxx_eval_logical_expression (ctx, t, boolean_true_node, |
09b42213 | 4628 | boolean_false_node, |
1227ba74 | 4629 | lval, |
09b42213 | 4630 | non_constant_p, overflow_p); |
4631 | break; | |
4632 | ||
4633 | case ARRAY_REF: | |
1227ba74 | 4634 | r = cxx_eval_array_reference (ctx, t, lval, |
09b42213 | 4635 | non_constant_p, overflow_p); |
4636 | break; | |
4637 | ||
4638 | case COMPONENT_REF: | |
4639 | if (is_overloaded_fn (t)) | |
4640 | { | |
4641 | /* We can only get here in checking mode via | |
4642 | build_non_dependent_expr, because any expression that | |
4643 | calls or takes the address of the function will have | |
4644 | pulled a FUNCTION_DECL out of the COMPONENT_REF. */ | |
f83e6885 | 4645 | gcc_checking_assert (ctx->quiet || errorcount); |
09b42213 | 4646 | *non_constant_p = true; |
4647 | return t; | |
4648 | } | |
1227ba74 | 4649 | r = cxx_eval_component_reference (ctx, t, lval, |
09b42213 | 4650 | non_constant_p, overflow_p); |
4651 | break; | |
4652 | ||
4653 | case BIT_FIELD_REF: | |
1227ba74 | 4654 | r = cxx_eval_bit_field_ref (ctx, t, lval, |
09b42213 | 4655 | non_constant_p, overflow_p); |
4656 | break; | |
4657 | ||
4658 | case COND_EXPR: | |
2a2770c6 | 4659 | if (jump_target && *jump_target) |
4660 | { | |
4661 | /* When jumping to a label, the label might be either in the | |
4662 | then or else blocks, so process then block first in skipping | |
4663 | mode first, and if we are still in the skipping mode at its end, | |
4664 | process the else block too. */ | |
4665 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), | |
4666 | lval, non_constant_p, overflow_p, | |
4667 | jump_target); | |
4668 | if (*jump_target) | |
4669 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), | |
4670 | lval, non_constant_p, overflow_p, | |
4671 | jump_target); | |
4672 | break; | |
4673 | } | |
1227ba74 | 4674 | r = cxx_eval_conditional_expression (ctx, t, lval, |
00f21715 | 4675 | non_constant_p, overflow_p, |
4676 | jump_target); | |
09b42213 | 4677 | break; |
31595caf | 4678 | case VEC_COND_EXPR: |
4679 | r = cxx_eval_vector_conditional_expression (ctx, t, non_constant_p, | |
4680 | overflow_p); | |
4681 | break; | |
09b42213 | 4682 | |
4683 | case CONSTRUCTOR: | |
1a3631bc | 4684 | if (TREE_CONSTANT (t)) |
58b0f9ce | 4685 | { |
4686 | /* Don't re-process a constant CONSTRUCTOR, but do fold it to | |
4687 | VECTOR_CST if applicable. */ | |
79e65a6b | 4688 | verify_constructor_flags (t); |
58b0f9ce | 4689 | if (TREE_CONSTANT (t)) |
4690 | return fold (t); | |
4691 | } | |
1227ba74 | 4692 | r = cxx_eval_bare_aggregate (ctx, t, lval, |
09b42213 | 4693 | non_constant_p, overflow_p); |
4694 | break; | |
4695 | ||
4696 | case VEC_INIT_EXPR: | |
4697 | /* We can get this in a defaulted constructor for a class with a | |
4698 | non-static data member of array type. Either the initializer will | |
4699 | be NULL, meaning default-initialization, or it will be an lvalue | |
4700 | or xvalue of the same type, meaning direct-initialization from the | |
4701 | corresponding member. */ | |
1227ba74 | 4702 | r = cxx_eval_vec_init (ctx, t, lval, |
09b42213 | 4703 | non_constant_p, overflow_p); |
4704 | break; | |
4705 | ||
09b42213 | 4706 | case VEC_PERM_EXPR: |
1227ba74 | 4707 | r = cxx_eval_trinary_expression (ctx, t, lval, |
09b42213 | 4708 | non_constant_p, overflow_p); |
4709 | break; | |
4710 | ||
941fafa5 | 4711 | case NOP_EXPR: |
4712 | if (REINTERPRET_CAST_P (t)) | |
4713 | { | |
4714 | if (!ctx->quiet) | |
d3a3cfb8 | 4715 | error_at (cp_expr_loc_or_loc (t, input_location), |
941fafa5 | 4716 | "a reinterpret_cast is not a constant expression"); |
4717 | *non_constant_p = true; | |
4718 | return t; | |
4719 | } | |
4720 | /* FALLTHROUGH. */ | |
09b42213 | 4721 | case CONVERT_EXPR: |
4722 | case VIEW_CONVERT_EXPR: | |
d2c63826 | 4723 | case UNARY_PLUS_EXPR: |
09b42213 | 4724 | { |
4725 | tree oldop = TREE_OPERAND (t, 0); | |
d2c63826 | 4726 | |
cf72f34d | 4727 | tree op = cxx_eval_constant_expression (ctx, oldop, |
1227ba74 | 4728 | lval, |
b2a43197 | 4729 | non_constant_p, overflow_p); |
09b42213 | 4730 | if (*non_constant_p) |
4731 | return t; | |
f16ed232 | 4732 | tree type = TREE_TYPE (t); |
4733 | if (TREE_CODE (op) == PTRMEM_CST | |
4734 | && !TYPE_PTRMEM_P (type)) | |
4735 | op = cplus_expand_constant (op); | |
941fafa5 | 4736 | |
6a9b35ef | 4737 | if (TREE_CODE (op) == PTRMEM_CST && tcode == NOP_EXPR) |
4738 | { | |
941fafa5 | 4739 | if (!same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (op)) |
4740 | && !can_convert_qual (type, op)) | |
4741 | op = cplus_expand_constant (op); | |
4742 | return cp_fold_convert (type, op); | |
6a9b35ef | 4743 | } |
cb768824 | 4744 | |
d03fa520 | 4745 | if (INDIRECT_TYPE_P (type) && TREE_CODE (op) == INTEGER_CST) |
09b42213 | 4746 | { |
cb768824 | 4747 | if (integer_zerop (op)) |
4748 | { | |
90ad495b | 4749 | if (TYPE_REF_P (type)) |
cb768824 | 4750 | { |
4751 | if (!ctx->quiet) | |
d3a3cfb8 | 4752 | error_at (cp_expr_loc_or_loc (t, input_location), |
cb768824 | 4753 | "dereferencing a null pointer"); |
4754 | *non_constant_p = true; | |
4755 | return t; | |
4756 | } | |
90ad495b | 4757 | else if (TYPE_PTR_P (TREE_TYPE (op))) |
cb768824 | 4758 | { |
4759 | tree from = TREE_TYPE (op); | |
4760 | ||
4761 | if (!can_convert (type, from, tf_none)) | |
4762 | { | |
4763 | if (!ctx->quiet) | |
d3a3cfb8 | 4764 | error_at (cp_expr_loc_or_loc (t, input_location), |
cb768824 | 4765 | "conversion of %qT null pointer to %qT " |
4766 | "is not a constant expression", | |
4767 | from, type); | |
4768 | *non_constant_p = true; | |
4769 | return t; | |
4770 | } | |
4771 | } | |
4772 | } | |
4773 | else | |
4774 | { | |
4775 | /* This detects for example: | |
4776 | reinterpret_cast<void*>(sizeof 0) | |
4777 | */ | |
4778 | if (!ctx->quiet) | |
d3a3cfb8 | 4779 | error_at (cp_expr_loc_or_loc (t, input_location), |
cb768824 | 4780 | "%<reinterpret_cast<%T>(%E)%> is not " |
ea034e2c | 4781 | "a constant expression", |
cb768824 | 4782 | type, op); |
4783 | *non_constant_p = true; | |
4784 | return t; | |
4785 | } | |
09b42213 | 4786 | } |
941fafa5 | 4787 | |
d2c63826 | 4788 | if (op == oldop && tcode != UNARY_PLUS_EXPR) |
09b42213 | 4789 | /* We didn't fold at the top so we could check for ptr-int |
4790 | conversion. */ | |
4791 | return fold (t); | |
941fafa5 | 4792 | |
6b53d686 | 4793 | /* Handle an array's bounds having been deduced after we built |
4794 | the wrapping expression. */ | |
4795 | if (same_type_ignoring_tlq_and_bounds_p (type, TREE_TYPE (op))) | |
4796 | r = op; | |
4797 | else if (tcode == UNARY_PLUS_EXPR) | |
d2c63826 | 4798 | r = fold_convert (TREE_TYPE (t), op); |
4799 | else | |
4800 | r = fold_build1 (tcode, type, op); | |
941fafa5 | 4801 | |
09b42213 | 4802 | /* Conversion of an out-of-range value has implementation-defined |
4803 | behavior; the language considers it different from arithmetic | |
4804 | overflow, which is undefined. */ | |
4805 | if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op)) | |
4806 | TREE_OVERFLOW (r) = false; | |
4807 | } | |
4808 | break; | |
4809 | ||
4810 | case EMPTY_CLASS_EXPR: | |
4811 | /* This is good enough for a function argument that might not get | |
4812 | used, and they can't do anything with it, so just return it. */ | |
4813 | return t; | |
4814 | ||
9c96033c | 4815 | case STATEMENT_LIST: |
00f21715 | 4816 | new_ctx = *ctx; |
4817 | new_ctx.ctor = new_ctx.object = NULL_TREE; | |
f83e6885 | 4818 | return cxx_eval_statement_list (&new_ctx, t, |
00f21715 | 4819 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4820 | |
4821 | case BIND_EXPR: | |
4822 | return cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t), | |
1227ba74 | 4823 | lval, |
00f21715 | 4824 | non_constant_p, overflow_p, |
4825 | jump_target); | |
9c96033c | 4826 | |
09b42213 | 4827 | case PREINCREMENT_EXPR: |
4828 | case POSTINCREMENT_EXPR: | |
4829 | case PREDECREMENT_EXPR: | |
4830 | case POSTDECREMENT_EXPR: | |
f83e6885 | 4831 | return cxx_eval_increment_expression (ctx, t, |
1227ba74 | 4832 | lval, non_constant_p, overflow_p); |
9c96033c | 4833 | |
4834 | case LAMBDA_EXPR: | |
09b42213 | 4835 | case NEW_EXPR: |
4836 | case VEC_NEW_EXPR: | |
4837 | case DELETE_EXPR: | |
4838 | case VEC_DELETE_EXPR: | |
4839 | case THROW_EXPR: | |
09b42213 | 4840 | case MODOP_EXPR: |
4841 | /* GCC internal stuff. */ | |
4842 | case VA_ARG_EXPR: | |
09b42213 | 4843 | case NON_DEPENDENT_EXPR: |
4844 | case BASELINK: | |
09b42213 | 4845 | case OFFSET_REF: |
f83e6885 | 4846 | if (!ctx->quiet) |
d3a3cfb8 | 4847 | error_at (cp_expr_loc_or_loc (t, input_location), |
ea034e2c | 4848 | "expression %qE is not a constant expression", t); |
09b42213 | 4849 | *non_constant_p = true; |
4850 | break; | |
4851 | ||
bb6e576c | 4852 | case OBJ_TYPE_REF: |
4853 | { | |
4854 | /* Virtual function call. Let the constexpr machinery figure out | |
4855 | the dynamic type. */ | |
4856 | int token = tree_to_shwi (OBJ_TYPE_REF_TOKEN (t)); | |
4857 | tree obj = OBJ_TYPE_REF_OBJECT (t); | |
4858 | obj = cxx_eval_constant_expression (ctx, obj, lval, non_constant_p, | |
4859 | overflow_p); | |
4860 | /* We expect something in the form of &x.D.2103.D.2094; get x. */ | |
85c4b1bb | 4861 | if (TREE_CODE (obj) != ADDR_EXPR |
4862 | || !DECL_P (get_base_address (TREE_OPERAND (obj, 0)))) | |
bb6e576c | 4863 | { |
4864 | if (!ctx->quiet) | |
4865 | error_at (cp_expr_loc_or_loc (t, input_location), | |
4866 | "expression %qE is not a constant expression", t); | |
4867 | *non_constant_p = true; | |
4868 | return t; | |
4869 | } | |
4870 | obj = TREE_OPERAND (obj, 0); | |
e3cb8102 | 4871 | while (TREE_CODE (obj) == COMPONENT_REF |
4872 | && DECL_FIELD_IS_BASE (TREE_OPERAND (obj, 1))) | |
bb6e576c | 4873 | obj = TREE_OPERAND (obj, 0); |
4874 | tree objtype = TREE_TYPE (obj); | |
4875 | /* Find the function decl in the virtual functions list. TOKEN is | |
4876 | the DECL_VINDEX that says which function we're looking for. */ | |
4877 | tree virtuals = BINFO_VIRTUALS (TYPE_BINFO (objtype)); | |
9a97d94a | 4878 | if (TARGET_VTABLE_USES_DESCRIPTORS) |
4879 | token /= MAX (TARGET_VTABLE_USES_DESCRIPTORS, 1); | |
bb6e576c | 4880 | r = TREE_VALUE (chain_index (token, virtuals)); |
4881 | break; | |
4882 | } | |
4883 | ||
cf72f34d | 4884 | case PLACEHOLDER_EXPR: |
85de9604 | 4885 | /* Use of the value or address of the current object. */ |
4886 | if (tree ctor = lookup_placeholder (ctx, lval, TREE_TYPE (t))) | |
4887 | return cxx_eval_constant_expression (ctx, ctor, lval, | |
4888 | non_constant_p, overflow_p); | |
4889 | /* A placeholder without a referent. We can get here when | |
4890 | checking whether NSDMIs are noexcept, or in massage_init_elt; | |
4891 | just say it's non-constant for now. */ | |
4892 | gcc_assert (ctx->quiet); | |
4893 | *non_constant_p = true; | |
cf72f34d | 4894 | break; |
4895 | ||
cf03ba19 | 4896 | case EXIT_EXPR: |
4897 | { | |
4898 | tree cond = TREE_OPERAND (t, 0); | |
4899 | cond = cxx_eval_constant_expression (ctx, cond, /*lval*/false, | |
4900 | non_constant_p, overflow_p); | |
4901 | VERIFY_CONSTANT (cond); | |
4902 | if (integer_nonzerop (cond)) | |
4903 | *jump_target = t; | |
4904 | } | |
4905 | break; | |
4906 | ||
9c96033c | 4907 | case GOTO_EXPR: |
00f21715 | 4908 | *jump_target = TREE_OPERAND (t, 0); |
d29e4e8c | 4909 | gcc_assert (breaks (jump_target) || continues (jump_target) |
4910 | /* Allow for jumping to a cdtor_label. */ | |
4911 | || returns (jump_target)); | |
00f21715 | 4912 | break; |
4913 | ||
9c96033c | 4914 | case LOOP_EXPR: |
f83e6885 | 4915 | cxx_eval_loop_expr (ctx, t, |
00f21715 | 4916 | non_constant_p, overflow_p, jump_target); |
4917 | break; | |
4918 | ||
9c96033c | 4919 | case SWITCH_EXPR: |
f83e6885 | 4920 | cxx_eval_switch_expr (ctx, t, |
00f21715 | 4921 | non_constant_p, overflow_p, jump_target); |
9c96033c | 4922 | break; |
4923 | ||
56c12fd4 | 4924 | case REQUIRES_EXPR: |
4925 | /* It's possible to get a requires-expression in a constant | |
4926 | expression. For example: | |
4927 | ||
4928 | template<typename T> concept bool C() { | |
4929 | return requires (T t) { t; }; | |
4930 | } | |
4931 | ||
4932 | template<typename T> requires !C<T>() void f(T); | |
4933 | ||
4934 | Normalization leaves f with the associated constraint | |
4935 | '!requires (T t) { ... }' which is not transformed into | |
4936 | a constraint. */ | |
4937 | if (!processing_template_decl) | |
4938 | return evaluate_constraint_expression (t, NULL_TREE); | |
4939 | else | |
4940 | *non_constant_p = true; | |
4941 | return t; | |
4942 | ||
24c6ee98 | 4943 | case ANNOTATE_EXPR: |
24c6ee98 | 4944 | r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
4945 | lval, | |
4946 | non_constant_p, overflow_p, | |
4947 | jump_target); | |
4948 | break; | |
4949 | ||
7285637a | 4950 | case USING_STMT: |
4951 | r = void_node; | |
4952 | break; | |
4953 | ||
09b42213 | 4954 | default: |
b9a3af23 | 4955 | if (STATEMENT_CODE_P (TREE_CODE (t))) |
4956 | { | |
4957 | /* This function doesn't know how to deal with pre-genericize | |
4958 | statements; this can only happen with statement-expressions, | |
4959 | so for now just fail. */ | |
4960 | if (!ctx->quiet) | |
4961 | error_at (EXPR_LOCATION (t), | |
ea034e2c | 4962 | "statement is not a constant expression"); |
b9a3af23 | 4963 | } |
4964 | else | |
4965 | internal_error ("unexpected expression %qE of kind %s", t, | |
4966 | get_tree_code_name (TREE_CODE (t))); | |
09b42213 | 4967 | *non_constant_p = true; |
4968 | break; | |
4969 | } | |
4970 | ||
4971 | if (r == error_mark_node) | |
4972 | *non_constant_p = true; | |
4973 | ||
4974 | if (*non_constant_p) | |
4975 | return t; | |
4976 | else | |
4977 | return r; | |
4978 | } | |
4979 | ||
6e1bbaae | 4980 | /* P0859: A function is needed for constant evaluation if it is a constexpr |
4981 | function that is named by an expression ([basic.def.odr]) that is | |
4982 | potentially constant evaluated. | |
4983 | ||
4984 | So we need to instantiate any constexpr functions mentioned by the | |
4985 | expression even if the definition isn't needed for evaluating the | |
4986 | expression. */ | |
4987 | ||
4988 | static tree | |
4989 | instantiate_cx_fn_r (tree *tp, int *walk_subtrees, void */*data*/) | |
4990 | { | |
4991 | if (TREE_CODE (*tp) == FUNCTION_DECL | |
4992 | && DECL_DECLARED_CONSTEXPR_P (*tp) | |
4993 | && !DECL_INITIAL (*tp) | |
eed138cf | 4994 | && !trivial_fn_p (*tp) |
6e1bbaae | 4995 | && DECL_TEMPLOID_INSTANTIATION (*tp)) |
4996 | { | |
4997 | ++function_depth; | |
4998 | instantiate_decl (*tp, /*defer_ok*/false, /*expl_inst*/false); | |
4999 | --function_depth; | |
5000 | } | |
5001 | else if (TREE_CODE (*tp) == CALL_EXPR | |
5002 | || TREE_CODE (*tp) == AGGR_INIT_EXPR) | |
5003 | { | |
5004 | if (EXPR_HAS_LOCATION (*tp)) | |
5005 | input_location = EXPR_LOCATION (*tp); | |
5006 | } | |
5007 | ||
5008 | if (!EXPR_P (*tp)) | |
5009 | *walk_subtrees = 0; | |
5010 | ||
5011 | return NULL_TREE; | |
5012 | } | |
5013 | static void | |
5014 | instantiate_constexpr_fns (tree t) | |
5015 | { | |
5016 | location_t loc = input_location; | |
5017 | cp_walk_tree_without_duplicates (&t, instantiate_cx_fn_r, NULL); | |
5018 | input_location = loc; | |
5019 | } | |
5020 | ||
18d371d3 | 5021 | /* ALLOW_NON_CONSTANT is false if T is required to be a constant expression. |
3f892eaf | 5022 | STRICT has the same sense as for constant_value_1: true if we only allow |
5023 | conforming C++ constant expressions, or false if we want a constant value | |
5024 | even if it doesn't conform. | |
1562c831 | 5025 | MANIFESTLY_CONST_EVAL is true if T is manifestly const-evaluated as |
18d371d3 | 5026 | per P0595 even when ALLOW_NON_CONSTANT is true. */ |
5027 | ||
09b42213 | 5028 | static tree |
cf72f34d | 5029 | cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, |
18d371d3 | 5030 | bool strict = true, |
1562c831 | 5031 | bool manifestly_const_eval = false, |
18d371d3 | 5032 | tree object = NULL_TREE) |
09b42213 | 5033 | { |
c300fe28 | 5034 | auto_timevar time (TV_CONSTEXPR); |
5035 | ||
09b42213 | 5036 | bool non_constant_p = false; |
5037 | bool overflow_p = false; | |
cf72f34d | 5038 | hash_map<tree,tree> map; |
2631cb67 | 5039 | |
2a2770c6 | 5040 | constexpr_ctx ctx = { NULL, &map, NULL, NULL, NULL, NULL, |
18d371d3 | 5041 | allow_non_constant, strict, |
1562c831 | 5042 | manifestly_const_eval || !allow_non_constant }; |
2631cb67 | 5043 | |
cf72f34d | 5044 | tree type = initialized_type (t); |
cf72f34d | 5045 | tree r = t; |
5046 | if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) | |
5047 | { | |
5048 | /* In C++14 an NSDMI can participate in aggregate initialization, | |
5049 | and can refer to the address of the object being initialized, so | |
5050 | we need to pass in the relevant VAR_DECL if we want to do the | |
5051 | evaluation in a single pass. The evaluation will dynamically | |
5052 | update ctx.values for the VAR_DECL. We use the same strategy | |
5053 | for C++11 constexpr constructors that refer to the object being | |
5054 | initialized. */ | |
5055 | ctx.ctor = build_constructor (type, NULL); | |
165d0d5b | 5056 | CONSTRUCTOR_NO_CLEARING (ctx.ctor) = true; |
9c96033c | 5057 | if (!object) |
5058 | { | |
5059 | if (TREE_CODE (t) == TARGET_EXPR) | |
5060 | object = TARGET_EXPR_SLOT (t); | |
5061 | else if (TREE_CODE (t) == AGGR_INIT_EXPR) | |
5062 | object = AGGR_INIT_EXPR_SLOT (t); | |
5063 | } | |
cf72f34d | 5064 | ctx.object = object; |
5065 | if (object) | |
5066 | gcc_assert (same_type_ignoring_top_level_qualifiers_p | |
5067 | (type, TREE_TYPE (object))); | |
5068 | if (object && DECL_P (object)) | |
5069 | map.put (object, ctx.ctor); | |
5070 | if (TREE_CODE (r) == TARGET_EXPR) | |
5071 | /* Avoid creating another CONSTRUCTOR when we expand the | |
5072 | TARGET_EXPR. */ | |
5073 | r = TARGET_EXPR_INITIAL (r); | |
5074 | } | |
5075 | ||
6e1bbaae | 5076 | instantiate_constexpr_fns (r); |
f83e6885 | 5077 | r = cxx_eval_constant_expression (&ctx, r, |
b2a43197 | 5078 | false, &non_constant_p, &overflow_p); |
09b42213 | 5079 | |
5080 | verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); | |
5081 | ||
bbcc9042 | 5082 | /* Mutable logic is a bit tricky: we want to allow initialization of |
5083 | constexpr variables with mutable members, but we can't copy those | |
5084 | members to another constexpr variable. */ | |
5085 | if (TREE_CODE (r) == CONSTRUCTOR | |
5086 | && CONSTRUCTOR_MUTABLE_POISON (r)) | |
09b42213 | 5087 | { |
09b42213 | 5088 | if (!allow_non_constant) |
bbcc9042 | 5089 | error ("%qE is not a constant expression because it refers to " |
5090 | "mutable subobjects of %qT", t, type); | |
09b42213 | 5091 | non_constant_p = true; |
5092 | } | |
5093 | ||
c6d97004 | 5094 | if (TREE_CODE (r) == CONSTRUCTOR |
165d0d5b | 5095 | && CONSTRUCTOR_NO_CLEARING (r)) |
c6d97004 | 5096 | { |
5097 | if (!allow_non_constant) | |
5098 | error ("%qE is not a constant expression because it refers to " | |
5099 | "an incompletely initialized variable", t); | |
5100 | TREE_CONSTANT (r) = false; | |
5101 | non_constant_p = true; | |
5102 | } | |
5103 | ||
09b42213 | 5104 | /* Technically we should check this for all subexpressions, but that |
5105 | runs into problems with our internal representation of pointer | |
5106 | subtraction and the 5.19 rules are still in flux. */ | |
5107 | if (CONVERT_EXPR_CODE_P (TREE_CODE (r)) | |
5108 | && ARITHMETIC_TYPE_P (TREE_TYPE (r)) | |
5109 | && TREE_CODE (TREE_OPERAND (r, 0)) == ADDR_EXPR) | |
5110 | { | |
5111 | if (!allow_non_constant) | |
5112 | error ("conversion from pointer type %qT " | |
ea034e2c | 5113 | "to arithmetic type %qT in a constant expression", |
09b42213 | 5114 | TREE_TYPE (TREE_OPERAND (r, 0)), TREE_TYPE (r)); |
5115 | non_constant_p = true; | |
5116 | } | |
5117 | ||
5118 | if (!non_constant_p && overflow_p) | |
5119 | non_constant_p = true; | |
5120 | ||
c6c0523b | 5121 | /* Unshare the result unless it's a CONSTRUCTOR in which case it's already |
5122 | unshared. */ | |
5123 | bool should_unshare = true; | |
5124 | if (r == t || TREE_CODE (r) == CONSTRUCTOR) | |
5125 | should_unshare = false; | |
5126 | ||
09b42213 | 5127 | if (non_constant_p && !allow_non_constant) |
5128 | return error_mark_node; | |
5129 | else if (non_constant_p && TREE_CONSTANT (r)) | |
5130 | { | |
18d371d3 | 5131 | /* If __builtin_is_constant_evaluated () was evaluated to true |
5132 | and the result is not a valid constant expression, we need to | |
5133 | punt. */ | |
1562c831 | 5134 | if (manifestly_const_eval) |
18d371d3 | 5135 | return cxx_eval_outermost_constant_expr (t, true, strict, |
5136 | false, object); | |
1d29f4ea | 5137 | /* This isn't actually constant, so unset TREE_CONSTANT. |
5138 | Don't clear TREE_CONSTANT on ADDR_EXPR, as the middle-end requires | |
5139 | it to be set if it is invariant address, even when it is not | |
5140 | a valid C++ constant expression. Wrap it with a NOP_EXPR | |
5141 | instead. */ | |
5142 | if (EXPR_P (r) && TREE_CODE (r) != ADDR_EXPR) | |
09b42213 | 5143 | r = copy_node (r); |
5144 | else if (TREE_CODE (r) == CONSTRUCTOR) | |
5145 | r = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (r), r); | |
5146 | else | |
5147 | r = build_nop (TREE_TYPE (r), r); | |
5148 | TREE_CONSTANT (r) = false; | |
5149 | } | |
59183fff | 5150 | else if (non_constant_p) |
09b42213 | 5151 | return t; |
5152 | ||
c6c0523b | 5153 | if (should_unshare) |
5154 | r = unshare_expr (r); | |
5155 | ||
09b42213 | 5156 | if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r))) |
5157 | { | |
59183fff | 5158 | r = adjust_temp_type (type, r); |
09b42213 | 5159 | if (TREE_CODE (t) == TARGET_EXPR |
5160 | && TARGET_EXPR_INITIAL (t) == r) | |
5161 | return t; | |
59183fff | 5162 | else if (TREE_CODE (t) != CONSTRUCTOR) |
09b42213 | 5163 | { |
5164 | r = get_target_expr (r); | |
5165 | TREE_CONSTANT (r) = true; | |
09b42213 | 5166 | } |
5167 | } | |
59183fff | 5168 | |
5169 | return r; | |
09b42213 | 5170 | } |
5171 | ||
5172 | /* Returns true if T is a valid subexpression of a constant expression, | |
5173 | even if it isn't itself a constant expression. */ | |
5174 | ||
5175 | bool | |
5176 | is_sub_constant_expr (tree t) | |
5177 | { | |
5178 | bool non_constant_p = false; | |
5179 | bool overflow_p = false; | |
cf72f34d | 5180 | hash_map <tree, tree> map; |
2631cb67 | 5181 | |
18d371d3 | 5182 | constexpr_ctx ctx |
5183 | = { NULL, &map, NULL, NULL, NULL, NULL, true, true, false }; | |
2631cb67 | 5184 | |
6e1bbaae | 5185 | instantiate_constexpr_fns (t); |
f83e6885 | 5186 | cxx_eval_constant_expression (&ctx, t, false, &non_constant_p, |
b2a43197 | 5187 | &overflow_p); |
09b42213 | 5188 | return !non_constant_p && !overflow_p; |
5189 | } | |
5190 | ||
5191 | /* If T represents a constant expression returns its reduced value. | |
5192 | Otherwise return error_mark_node. If T is dependent, then | |
5193 | return NULL. */ | |
5194 | ||
5195 | tree | |
cf72f34d | 5196 | cxx_constant_value (tree t, tree decl) |
09b42213 | 5197 | { |
18d371d3 | 5198 | return cxx_eval_outermost_constant_expr (t, false, true, true, decl); |
09b42213 | 5199 | } |
5200 | ||
d2c63826 | 5201 | /* Helper routine for fold_simple function. Either return simplified |
5202 | expression T, otherwise NULL_TREE. | |
5203 | In contrast to cp_fully_fold, and to maybe_constant_value, we try to fold | |
5204 | even if we are within template-declaration. So be careful on call, as in | |
5205 | such case types can be undefined. */ | |
5206 | ||
5207 | static tree | |
5208 | fold_simple_1 (tree t) | |
5209 | { | |
5210 | tree op1; | |
5211 | enum tree_code code = TREE_CODE (t); | |
5212 | ||
5213 | switch (code) | |
5214 | { | |
5215 | case INTEGER_CST: | |
5216 | case REAL_CST: | |
5217 | case VECTOR_CST: | |
5218 | case FIXED_CST: | |
5219 | case COMPLEX_CST: | |
5220 | return t; | |
5221 | ||
5222 | case SIZEOF_EXPR: | |
5223 | return fold_sizeof_expr (t); | |
5224 | ||
5225 | case ABS_EXPR: | |
19b4138e | 5226 | case ABSU_EXPR: |
d2c63826 | 5227 | case CONJ_EXPR: |
5228 | case REALPART_EXPR: | |
5229 | case IMAGPART_EXPR: | |
5230 | case NEGATE_EXPR: | |
5231 | case BIT_NOT_EXPR: | |
5232 | case TRUTH_NOT_EXPR: | |
5233 | case NOP_EXPR: | |
5234 | case VIEW_CONVERT_EXPR: | |
5235 | case CONVERT_EXPR: | |
5236 | case FLOAT_EXPR: | |
5237 | case FIX_TRUNC_EXPR: | |
5238 | case FIXED_CONVERT_EXPR: | |
5239 | case ADDR_SPACE_CONVERT_EXPR: | |
5240 | ||
5241 | op1 = TREE_OPERAND (t, 0); | |
5242 | ||
5243 | t = const_unop (code, TREE_TYPE (t), op1); | |
5244 | if (!t) | |
5245 | return NULL_TREE; | |
5246 | ||
5247 | if (CONVERT_EXPR_CODE_P (code) | |
5248 | && TREE_OVERFLOW_P (t) && !TREE_OVERFLOW_P (op1)) | |
5249 | TREE_OVERFLOW (t) = false; | |
5250 | return t; | |
5251 | ||
5252 | default: | |
5253 | return NULL_TREE; | |
5254 | } | |
5255 | } | |
5256 | ||
5257 | /* If T is a simple constant expression, returns its simplified value. | |
6fe5fea9 | 5258 | Otherwise returns T. In contrast to maybe_constant_value we |
d2c63826 | 5259 | simplify only few operations on constant-expressions, and we don't |
5260 | try to simplify constexpressions. */ | |
5261 | ||
5262 | tree | |
5263 | fold_simple (tree t) | |
5264 | { | |
d2c63826 | 5265 | if (processing_template_decl) |
5266 | return t; | |
5267 | ||
6fe5fea9 | 5268 | tree r = fold_simple_1 (t); |
5269 | if (r) | |
5270 | return r; | |
d2c63826 | 5271 | |
6fe5fea9 | 5272 | return t; |
d2c63826 | 5273 | } |
5274 | ||
09b42213 | 5275 | /* If T is a constant expression, returns its reduced value. |
5276 | Otherwise, if T does not have TREE_CONSTANT set, returns T. | |
1562c831 | 5277 | Otherwise, returns a version of T without TREE_CONSTANT. |
5278 | MANIFESTLY_CONST_EVAL is true if T is manifestly const-evaluated | |
5279 | as per P0595. */ | |
09b42213 | 5280 | |
b601ad30 | 5281 | static GTY((deletable)) hash_map<tree, tree> *cv_cache; |
5282 | ||
5283 | tree | |
1562c831 | 5284 | maybe_constant_value (tree t, tree decl, bool manifestly_const_eval) |
09b42213 | 5285 | { |
5286 | tree r; | |
5287 | ||
7e1f8be4 | 5288 | if (!is_nondependent_constant_expression (t)) |
09b42213 | 5289 | { |
5290 | if (TREE_OVERFLOW_P (t)) | |
5291 | { | |
5292 | t = build_nop (TREE_TYPE (t), t); | |
5293 | TREE_CONSTANT (t) = false; | |
5294 | } | |
5295 | return t; | |
5296 | } | |
b601ad30 | 5297 | else if (CONSTANT_CLASS_P (t)) |
5298 | /* No caching or evaluation needed. */ | |
5299 | return t; | |
5300 | ||
1562c831 | 5301 | if (manifestly_const_eval) |
5302 | return cxx_eval_outermost_constant_expr (t, true, true, true, decl); | |
5303 | ||
b601ad30 | 5304 | if (cv_cache == NULL) |
5305 | cv_cache = hash_map<tree, tree>::create_ggc (101); | |
5306 | if (tree *cached = cv_cache->get (t)) | |
5307 | return *cached; | |
09b42213 | 5308 | |
18d371d3 | 5309 | r = cxx_eval_outermost_constant_expr (t, true, true, false, decl); |
5e8689fb | 5310 | gcc_checking_assert (r == t |
5311 | || CONVERT_EXPR_P (t) | |
5312 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
5313 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
5314 | || !cp_tree_equal (r, t)); | |
b601ad30 | 5315 | cv_cache->put (t, r); |
09b42213 | 5316 | return r; |
5317 | } | |
5318 | ||
2a655a4c | 5319 | /* Dispose of the whole CV_CACHE. */ |
5320 | ||
5321 | static void | |
5322 | clear_cv_cache (void) | |
5323 | { | |
5324 | if (cv_cache != NULL) | |
5325 | cv_cache->empty (); | |
5326 | } | |
5327 | ||
f553d9f8 | 5328 | /* Dispose of the whole CV_CACHE and FOLD_CACHE. */ |
a0c919f7 | 5329 | |
5330 | void | |
f553d9f8 | 5331 | clear_cv_and_fold_caches (void) |
a0c919f7 | 5332 | { |
2a655a4c | 5333 | clear_cv_cache (); |
f553d9f8 | 5334 | clear_fold_cache (); |
a0c919f7 | 5335 | } |
5336 | ||
21131a05 | 5337 | /* Like maybe_constant_value but first fully instantiate the argument. |
5338 | ||
5339 | Note: this is equivalent to instantiate_non_dependent_expr_sfinae | |
006b503a | 5340 | (t, complain) followed by maybe_constant_value but is more efficient, |
5341 | because it calls instantiation_dependent_expression_p and | |
5342 | potential_constant_expression at most once. | |
5343 | ||
5344 | Callers should generally pass their active complain, or if they are in a | |
5345 | non-template, diagnosing context, they can use the default of | |
5346 | tf_warning_or_error. Callers that might be within a template context, don't | |
5347 | have a complain parameter, and aren't going to remember the result for long | |
5348 | (e.g. null_ptr_cst_p), can pass tf_none and deal with error_mark_node | |
5349 | appropriately. */ | |
21131a05 | 5350 | |
5351 | tree | |
006b503a | 5352 | fold_non_dependent_expr (tree t, |
5353 | tsubst_flags_t complain /* = tf_warning_or_error */) | |
21131a05 | 5354 | { |
5355 | if (t == NULL_TREE) | |
5356 | return NULL_TREE; | |
5357 | ||
5358 | /* If we're in a template, but T isn't value dependent, simplify | |
5359 | it. We're supposed to treat: | |
5360 | ||
5361 | template <typename T> void f(T[1 + 1]); | |
5362 | template <typename T> void f(T[2]); | |
5363 | ||
5364 | as two declarations of the same function, for example. */ | |
5365 | if (processing_template_decl) | |
5366 | { | |
7e1f8be4 | 5367 | if (is_nondependent_constant_expression (t)) |
21131a05 | 5368 | { |
c8a9f04c | 5369 | processing_template_decl_sentinel s; |
006b503a | 5370 | t = instantiate_non_dependent_expr_internal (t, complain); |
21131a05 | 5371 | |
5372 | if (type_unknown_p (t) | |
5373 | || BRACE_ENCLOSED_INITIALIZER_P (t)) | |
5374 | { | |
5375 | if (TREE_OVERFLOW_P (t)) | |
5376 | { | |
5377 | t = build_nop (TREE_TYPE (t), t); | |
5378 | TREE_CONSTANT (t) = false; | |
5379 | } | |
5380 | return t; | |
5381 | } | |
5382 | ||
18d371d3 | 5383 | tree r = cxx_eval_outermost_constant_expr (t, true, true, false, |
5384 | NULL_TREE); | |
21131a05 | 5385 | /* cp_tree_equal looks through NOPs, so allow them. */ |
5e8689fb | 5386 | gcc_checking_assert (r == t |
5387 | || CONVERT_EXPR_P (t) | |
5388 | || TREE_CODE (t) == VIEW_CONVERT_EXPR | |
5389 | || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) | |
5390 | || !cp_tree_equal (r, t)); | |
21131a05 | 5391 | return r; |
5392 | } | |
5393 | else if (TREE_OVERFLOW_P (t)) | |
5394 | { | |
5395 | t = build_nop (TREE_TYPE (t), t); | |
5396 | TREE_CONSTANT (t) = false; | |
5397 | } | |
5398 | return t; | |
5399 | } | |
5400 | ||
5401 | return maybe_constant_value (t); | |
5402 | } | |
5403 | ||
09b42213 | 5404 | /* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather |
18d371d3 | 5405 | than wrapped in a TARGET_EXPR. |
5406 | ALLOW_NON_CONSTANT is false if T is required to be a constant expression. | |
1562c831 | 5407 | MANIFESTLY_CONST_EVAL is true if T is manifestly const-evaluated as |
18d371d3 | 5408 | per P0595 even when ALLOW_NON_CONSTANT is true. */ |
09b42213 | 5409 | |
0c703e14 | 5410 | static tree |
18d371d3 | 5411 | maybe_constant_init_1 (tree t, tree decl, bool allow_non_constant, |
1562c831 | 5412 | bool manifestly_const_eval) |
09b42213 | 5413 | { |
d2c63826 | 5414 | if (!t) |
5415 | return t; | |
09b42213 | 5416 | if (TREE_CODE (t) == EXPR_STMT) |
5417 | t = TREE_OPERAND (t, 0); | |
5418 | if (TREE_CODE (t) == CONVERT_EXPR | |
5419 | && VOID_TYPE_P (TREE_TYPE (t))) | |
5420 | t = TREE_OPERAND (t, 0); | |
9c96033c | 5421 | if (TREE_CODE (t) == INIT_EXPR) |
5422 | t = TREE_OPERAND (t, 1); | |
c6d97004 | 5423 | if (TREE_CODE (t) == TARGET_EXPR) |
5424 | t = TARGET_EXPR_INITIAL (t); | |
7e1f8be4 | 5425 | if (!is_nondependent_static_init_expression (t)) |
2055d27a | 5426 | /* Don't try to evaluate it. */; |
0c703e14 | 5427 | else if (CONSTANT_CLASS_P (t) && allow_non_constant) |
b601ad30 | 5428 | /* No evaluation needed. */; |
2055d27a | 5429 | else |
18d371d3 | 5430 | t = cxx_eval_outermost_constant_expr (t, allow_non_constant, |
fbe79a84 | 5431 | /*strict*/false, |
1562c831 | 5432 | manifestly_const_eval, decl); |
09b42213 | 5433 | if (TREE_CODE (t) == TARGET_EXPR) |
5434 | { | |
5435 | tree init = TARGET_EXPR_INITIAL (t); | |
5436 | if (TREE_CODE (init) == CONSTRUCTOR) | |
5437 | t = init; | |
5438 | } | |
5439 | return t; | |
5440 | } | |
5441 | ||
0c703e14 | 5442 | /* Wrapper for maybe_constant_init_1 which permits non constants. */ |
5443 | ||
5444 | tree | |
1562c831 | 5445 | maybe_constant_init (tree t, tree decl, bool manifestly_const_eval) |
0c703e14 | 5446 | { |
1562c831 | 5447 | return maybe_constant_init_1 (t, decl, true, manifestly_const_eval); |
0c703e14 | 5448 | } |
5449 | ||
5450 | /* Wrapper for maybe_constant_init_1 which does not permit non constants. */ | |
5451 | ||
5452 | tree | |
5453 | cxx_constant_init (tree t, tree decl) | |
5454 | { | |
18d371d3 | 5455 | return maybe_constant_init_1 (t, decl, false, true); |
0c703e14 | 5456 | } |
5457 | ||
09b42213 | 5458 | #if 0 |
5459 | /* FIXME see ADDR_EXPR section in potential_constant_expression_1. */ | |
5460 | /* Return true if the object referred to by REF has automatic or thread | |
5461 | local storage. */ | |
5462 | ||
5463 | enum { ck_ok, ck_bad, ck_unknown }; | |
5464 | static int | |
5465 | check_automatic_or_tls (tree ref) | |
5466 | { | |
3754d046 | 5467 | machine_mode mode; |
81bc0f0f | 5468 | poly_int64 bitsize, bitpos; |
09b42213 | 5469 | tree offset; |
5470 | int volatilep = 0, unsignedp = 0; | |
5471 | tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset, | |
5472 | &mode, &unsignedp, &volatilep, false); | |
5473 | duration_kind dk; | |
5474 | ||
5475 | /* If there isn't a decl in the middle, we don't know the linkage here, | |
5476 | and this isn't a constant expression anyway. */ | |
5477 | if (!DECL_P (decl)) | |
5478 | return ck_unknown; | |
5479 | dk = decl_storage_duration (decl); | |
5480 | return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok; | |
5481 | } | |
5482 | #endif | |
5483 | ||
5484 | /* Return true if T denotes a potentially constant expression. Issue | |
5485 | diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true, | |
7e1f8be4 | 5486 | an lvalue-rvalue conversion is implied. If NOW is true, we want to |
5487 | consider the expression in the current context, independent of constexpr | |
5488 | substitution. | |
09b42213 | 5489 | |
5490 | C++0x [expr.const] used to say | |
5491 | ||
5492 | 6 An expression is a potential constant expression if it is | |
5493 | a constant expression where all occurrences of function | |
5494 | parameters are replaced by arbitrary constant expressions | |
5495 | of the appropriate type. | |
5496 | ||
5497 | 2 A conditional expression is a constant expression unless it | |
5498 | involves one of the following as a potentially evaluated | |
5499 | subexpression (3.2), but subexpressions of logical AND (5.14), | |
5500 | logical OR (5.15), and conditional (5.16) operations that are | |
5501 | not evaluated are not considered. */ | |
5502 | ||
5503 | static bool | |
7e1f8be4 | 5504 | potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, |
32fee334 | 5505 | tsubst_flags_t flags, tree *jump_target) |
09b42213 | 5506 | { |
7e1f8be4 | 5507 | #define RECUR(T,RV) \ |
32fee334 | 5508 | potential_constant_expression_1 ((T), (RV), strict, now, flags, jump_target) |
7e1f8be4 | 5509 | |
09b42213 | 5510 | enum { any = false, rval = true }; |
5511 | int i; | |
5512 | tree tmp; | |
5513 | ||
5514 | if (t == error_mark_node) | |
5515 | return false; | |
5516 | if (t == NULL_TREE) | |
5517 | return true; | |
d3a3cfb8 | 5518 | location_t loc = cp_expr_loc_or_loc (t, input_location); |
32fee334 | 5519 | |
5520 | if (*jump_target) | |
5521 | /* If we are jumping, ignore everything. This is simpler than the | |
5522 | cxx_eval_constant_expression handling because we only need to be | |
5523 | conservatively correct, and we don't necessarily have a constant value | |
5524 | available, so we don't bother with switch tracking. */ | |
5525 | return true; | |
5526 | ||
04ced4a2 | 5527 | if (TREE_THIS_VOLATILE (t) && want_rval) |
09b42213 | 5528 | { |
5529 | if (flags & tf_error) | |
04ced4a2 | 5530 | error_at (loc, "lvalue-to-rvalue conversion of a volatile lvalue " |
5531 | "%qE with type %qT", t, TREE_TYPE (t)); | |
09b42213 | 5532 | return false; |
5533 | } | |
5534 | if (CONSTANT_CLASS_P (t)) | |
5535 | return true; | |
c7282bf2 | 5536 | if (CODE_CONTAINS_STRUCT (TREE_CODE (t), TS_TYPED) |
5537 | && TREE_TYPE (t) == error_mark_node) | |
5538 | return false; | |
09b42213 | 5539 | |
5540 | switch (TREE_CODE (t)) | |
5541 | { | |
5542 | case FUNCTION_DECL: | |
5543 | case BASELINK: | |
5544 | case TEMPLATE_DECL: | |
5545 | case OVERLOAD: | |
5546 | case TEMPLATE_ID_EXPR: | |
5547 | case LABEL_DECL: | |
5548 | case LABEL_EXPR: | |
9c96033c | 5549 | case CASE_LABEL_EXPR: |
09b42213 | 5550 | case CONST_DECL: |
5551 | case SIZEOF_EXPR: | |
5552 | case ALIGNOF_EXPR: | |
5553 | case OFFSETOF_EXPR: | |
5554 | case NOEXCEPT_EXPR: | |
5555 | case TEMPLATE_PARM_INDEX: | |
5556 | case TRAIT_EXPR: | |
5557 | case IDENTIFIER_NODE: | |
5558 | case USERDEF_LITERAL: | |
5559 | /* We can see a FIELD_DECL in a pointer-to-member expression. */ | |
5560 | case FIELD_DECL: | |
d2c63826 | 5561 | case RESULT_DECL: |
09b42213 | 5562 | case USING_DECL: |
9c96033c | 5563 | case USING_STMT: |
cf72f34d | 5564 | case PLACEHOLDER_EXPR: |
56c12fd4 | 5565 | case REQUIRES_EXPR: |
33603066 | 5566 | case STATIC_ASSERT: |
90567983 | 5567 | case DEBUG_BEGIN_STMT: |
09b42213 | 5568 | return true; |
5569 | ||
32fee334 | 5570 | case RETURN_EXPR: |
5571 | if (!RECUR (TREE_OPERAND (t, 0), any)) | |
5572 | return false; | |
5573 | /* FALLTHROUGH */ | |
5574 | ||
5575 | case BREAK_STMT: | |
5576 | case CONTINUE_STMT: | |
5577 | *jump_target = t; | |
5578 | return true; | |
5579 | ||
7e1f8be4 | 5580 | case PARM_DECL: |
5581 | if (now) | |
5582 | { | |
5583 | if (flags & tf_error) | |
5584 | error ("%qE is not a constant expression", t); | |
5585 | return false; | |
5586 | } | |
5587 | return true; | |
5588 | ||
09b42213 | 5589 | case AGGR_INIT_EXPR: |
5590 | case CALL_EXPR: | |
5591 | /* -- an invocation of a function other than a constexpr function | |
5592 | or a constexpr constructor. */ | |
5593 | { | |
5594 | tree fun = get_function_named_in_call (t); | |
5595 | const int nargs = call_expr_nargs (t); | |
5596 | i = 0; | |
5597 | ||
9c96033c | 5598 | if (fun == NULL_TREE) |
5599 | { | |
732905bb | 5600 | /* Reset to allow the function to continue past the end |
5601 | of the block below. Otherwise return early. */ | |
5602 | bool bail = true; | |
5603 | ||
32cf7025 | 5604 | if (TREE_CODE (t) == CALL_EXPR |
5605 | && CALL_EXPR_FN (t) == NULL_TREE) | |
5606 | switch (CALL_EXPR_IFN (t)) | |
5607 | { | |
5608 | /* These should be ignored, they are optimized away from | |
5609 | constexpr functions. */ | |
5610 | case IFN_UBSAN_NULL: | |
5611 | case IFN_UBSAN_BOUNDS: | |
5612 | case IFN_UBSAN_VPTR: | |
3c77f69c | 5613 | case IFN_FALLTHROUGH: |
32cf7025 | 5614 | return true; |
732905bb | 5615 | |
5616 | case IFN_ADD_OVERFLOW: | |
5617 | case IFN_SUB_OVERFLOW: | |
5618 | case IFN_MUL_OVERFLOW: | |
6e1b2ffb | 5619 | case IFN_LAUNDER: |
732905bb | 5620 | bail = false; |
5621 | ||
32cf7025 | 5622 | default: |
5623 | break; | |
5624 | } | |
732905bb | 5625 | |
5626 | if (bail) | |
5627 | { | |
5628 | /* fold_call_expr can't do anything with IFN calls. */ | |
5629 | if (flags & tf_error) | |
d6a08f5c | 5630 | error_at (loc, "call to internal function %qE", t); |
732905bb | 5631 | return false; |
5632 | } | |
9c96033c | 5633 | } |
732905bb | 5634 | |
5635 | if (fun && is_overloaded_fn (fun)) | |
09b42213 | 5636 | { |
5637 | if (TREE_CODE (fun) == FUNCTION_DECL) | |
5638 | { | |
5639 | if (builtin_valid_in_constant_expr_p (fun)) | |
5640 | return true; | |
5641 | if (!DECL_DECLARED_CONSTEXPR_P (fun) | |
5642 | /* Allow any built-in function; if the expansion | |
5643 | isn't constant, we'll deal with that then. */ | |
a0e9bfbb | 5644 | && !fndecl_built_in_p (fun)) |
09b42213 | 5645 | { |
5646 | if (flags & tf_error) | |
5647 | { | |
5967b28b | 5648 | error_at (loc, "call to non-%<constexpr%> function %qD", |
d6a08f5c | 5649 | fun); |
09b42213 | 5650 | explain_invalid_constexpr_fn (fun); |
5651 | } | |
5652 | return false; | |
5653 | } | |
5654 | /* A call to a non-static member function takes the address | |
5655 | of the object as the first argument. But in a constant | |
5656 | expression the address will be folded away, so look | |
5657 | through it now. */ | |
5658 | if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) | |
5659 | && !DECL_CONSTRUCTOR_P (fun)) | |
5660 | { | |
5661 | tree x = get_nth_callarg (t, 0); | |
5662 | if (is_this_parameter (x)) | |
cf72f34d | 5663 | return true; |
7e1f8be4 | 5664 | /* Don't require an immediately constant value, as |
5665 | constexpr substitution might not use the value. */ | |
5666 | bool sub_now = false; | |
5667 | if (!potential_constant_expression_1 (x, rval, strict, | |
32fee334 | 5668 | sub_now, flags, |
5669 | jump_target)) | |
09b42213 | 5670 | return false; |
5671 | i = 1; | |
5672 | } | |
5673 | } | |
5674 | else | |
5675 | { | |
2055d27a | 5676 | if (!RECUR (fun, true)) |
09b42213 | 5677 | return false; |
5678 | fun = get_first_fn (fun); | |
5679 | } | |
5680 | /* Skip initial arguments to base constructors. */ | |
5681 | if (DECL_BASE_CONSTRUCTOR_P (fun)) | |
5682 | i = num_artificial_parms_for (fun); | |
5683 | fun = DECL_ORIGIN (fun); | |
5684 | } | |
732905bb | 5685 | else if (fun) |
09b42213 | 5686 | { |
2055d27a | 5687 | if (RECUR (fun, rval)) |
09b42213 | 5688 | /* Might end up being a constant function pointer. */; |
5689 | else | |
5690 | return false; | |
5691 | } | |
5692 | for (; i < nargs; ++i) | |
5693 | { | |
5694 | tree x = get_nth_callarg (t, i); | |
b2742b58 | 5695 | /* In a template, reference arguments haven't been converted to |
5696 | REFERENCE_TYPE and we might not even know if the parameter | |
5697 | is a reference, so accept lvalue constants too. */ | |
5698 | bool rv = processing_template_decl ? any : rval; | |
7e1f8be4 | 5699 | /* Don't require an immediately constant value, as constexpr |
5700 | substitution might not use the value of the argument. */ | |
5701 | bool sub_now = false; | |
5702 | if (!potential_constant_expression_1 (x, rv, strict, | |
32fee334 | 5703 | sub_now, flags, jump_target)) |
09b42213 | 5704 | return false; |
5705 | } | |
5706 | return true; | |
5707 | } | |
5708 | ||
5709 | case NON_LVALUE_EXPR: | |
5710 | /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to | |
5711 | -- an lvalue of integral type that refers to a non-volatile | |
5712 | const variable or static data member initialized with | |
5713 | constant expressions, or | |
5714 | ||
5715 | -- an lvalue of literal type that refers to non-volatile | |
5716 | object defined with constexpr, or that refers to a | |
5717 | sub-object of such an object; */ | |
2055d27a | 5718 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 5719 | |
5720 | case VAR_DECL: | |
9c8aeb66 | 5721 | if (DECL_HAS_VALUE_EXPR_P (t)) |
297de7bc | 5722 | { |
d0e2b7e7 | 5723 | if (now && is_normal_capture_proxy (t)) |
297de7bc | 5724 | { |
5725 | /* -- in a lambda-expression, a reference to this or to a | |
5726 | variable with automatic storage duration defined outside that | |
5727 | lambda-expression, where the reference would be an | |
5728 | odr-use. */ | |
5729 | if (flags & tf_error) | |
5730 | { | |
5731 | tree cap = DECL_CAPTURED_VARIABLE (t); | |
5732 | error ("lambda capture of %qE is not a constant expression", | |
5733 | cap); | |
5734 | if (!want_rval && decl_constant_var_p (cap)) | |
5735 | inform (input_location, "because it is used as a glvalue"); | |
5736 | } | |
5737 | return false; | |
5738 | } | |
5739 | return RECUR (DECL_VALUE_EXPR (t), rval); | |
5740 | } | |
2055d27a | 5741 | if (want_rval |
33603066 | 5742 | && !var_in_maybe_constexpr_fn (t) |
c7282bf2 | 5743 | && !type_dependent_expression_p (t) |
8d6486e1 | 5744 | && !decl_maybe_constant_var_p (t) |
2055d27a | 5745 | && (strict |
5746 | || !CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (t)) | |
8d6486e1 | 5747 | || (DECL_INITIAL (t) |
5748 | && !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (t))) | |
c7282bf2 | 5749 | && COMPLETE_TYPE_P (TREE_TYPE (t)) |
5750 | && !is_really_empty_class (TREE_TYPE (t))) | |
09b42213 | 5751 | { |
5752 | if (flags & tf_error) | |
5753 | non_const_var_error (t); | |
5754 | return false; | |
5755 | } | |
5756 | return true; | |
5757 | ||
5758 | case NOP_EXPR: | |
5759 | case CONVERT_EXPR: | |
5760 | case VIEW_CONVERT_EXPR: | |
5761 | /* -- a reinterpret_cast. FIXME not implemented, and this rule | |
5762 | may change to something more specific to type-punning (DR 1312). */ | |
5763 | { | |
5764 | tree from = TREE_OPERAND (t, 0); | |
d03fa520 | 5765 | if (INDIRECT_TYPE_P (TREE_TYPE (t)) |
09b42213 | 5766 | && TREE_CODE (from) == INTEGER_CST |
5767 | && !integer_zerop (from)) | |
5768 | { | |
5769 | if (flags & tf_error) | |
d6a08f5c | 5770 | error_at (loc, "reinterpret_cast from integer to pointer"); |
09b42213 | 5771 | return false; |
5772 | } | |
2055d27a | 5773 | return (RECUR (from, TREE_CODE (t) != VIEW_CONVERT_EXPR)); |
09b42213 | 5774 | } |
5775 | ||
cd45162d | 5776 | case ADDRESSOF_EXPR: |
5777 | /* This is like ADDR_EXPR, except it won't form pointer-to-member. */ | |
5778 | t = TREE_OPERAND (t, 0); | |
5779 | goto handle_addr_expr; | |
5780 | ||
09b42213 | 5781 | case ADDR_EXPR: |
5782 | /* -- a unary operator & that is applied to an lvalue that | |
5783 | designates an object with thread or automatic storage | |
5784 | duration; */ | |
5785 | t = TREE_OPERAND (t, 0); | |
5786 | ||
5787 | if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t)) | |
5788 | /* A pointer-to-member constant. */ | |
5789 | return true; | |
5790 | ||
cd45162d | 5791 | handle_addr_expr: |
09b42213 | 5792 | #if 0 |
5793 | /* FIXME adjust when issue 1197 is fully resolved. For now don't do | |
5794 | any checking here, as we might dereference the pointer later. If | |
5795 | we remove this code, also remove check_automatic_or_tls. */ | |
5796 | i = check_automatic_or_tls (t); | |
5797 | if (i == ck_ok) | |
5798 | return true; | |
5799 | if (i == ck_bad) | |
5800 | { | |
5801 | if (flags & tf_error) | |
5802 | error ("address-of an object %qE with thread local or " | |
5803 | "automatic storage is not a constant expression", t); | |
5804 | return false; | |
5805 | } | |
5806 | #endif | |
2055d27a | 5807 | return RECUR (t, any); |
09b42213 | 5808 | |
20b34a56 | 5809 | case REALPART_EXPR: |
5810 | case IMAGPART_EXPR: | |
09b42213 | 5811 | case COMPONENT_REF: |
5812 | case BIT_FIELD_REF: | |
5813 | case ARROW_EXPR: | |
5814 | case OFFSET_REF: | |
5815 | /* -- a class member access unless its postfix-expression is | |
5816 | of literal type or of pointer to literal type. */ | |
5817 | /* This test would be redundant, as it follows from the | |
5818 | postfix-expression being a potential constant expression. */ | |
eade0940 | 5819 | if (type_unknown_p (t)) |
5820 | return true; | |
2055d27a | 5821 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 5822 | |
5823 | case EXPR_PACK_EXPANSION: | |
2055d27a | 5824 | return RECUR (PACK_EXPANSION_PATTERN (t), want_rval); |
09b42213 | 5825 | |
5826 | case INDIRECT_REF: | |
5827 | { | |
5828 | tree x = TREE_OPERAND (t, 0); | |
5829 | STRIP_NOPS (x); | |
997bbf70 | 5830 | if (is_this_parameter (x) && !is_capture_proxy (x)) |
09b42213 | 5831 | { |
b7e4a558 | 5832 | if (!var_in_maybe_constexpr_fn (x)) |
09b42213 | 5833 | { |
5834 | if (flags & tf_error) | |
d6a08f5c | 5835 | error_at (loc, "use of %<this%> in a constant expression"); |
09b42213 | 5836 | return false; |
5837 | } | |
09b42213 | 5838 | return true; |
5839 | } | |
2055d27a | 5840 | return RECUR (x, rval); |
09b42213 | 5841 | } |
5842 | ||
9c96033c | 5843 | case STATEMENT_LIST: |
5844 | { | |
5845 | tree_stmt_iterator i; | |
5846 | for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) | |
5847 | { | |
2055d27a | 5848 | if (!RECUR (tsi_stmt (i), any)) |
9c96033c | 5849 | return false; |
5850 | } | |
5851 | return true; | |
5852 | } | |
5853 | break; | |
5854 | ||
5855 | case MODIFY_EXPR: | |
5856 | if (cxx_dialect < cxx14) | |
5857 | goto fail; | |
2055d27a | 5858 | if (!RECUR (TREE_OPERAND (t, 0), any)) |
9c96033c | 5859 | return false; |
2055d27a | 5860 | if (!RECUR (TREE_OPERAND (t, 1), rval)) |
9c96033c | 5861 | return false; |
5862 | return true; | |
5863 | ||
5864 | case MODOP_EXPR: | |
5865 | if (cxx_dialect < cxx14) | |
5866 | goto fail; | |
2055d27a | 5867 | if (!RECUR (TREE_OPERAND (t, 0), rval)) |
9c96033c | 5868 | return false; |
2055d27a | 5869 | if (!RECUR (TREE_OPERAND (t, 2), rval)) |
9c96033c | 5870 | return false; |
5871 | return true; | |
5872 | ||
9c96033c | 5873 | case DO_STMT: |
2055d27a | 5874 | if (!RECUR (DO_COND (t), rval)) |
9c96033c | 5875 | return false; |
2055d27a | 5876 | if (!RECUR (DO_BODY (t), any)) |
9c96033c | 5877 | return false; |
32fee334 | 5878 | if (breaks (jump_target) || continues (jump_target)) |
5879 | *jump_target = NULL_TREE; | |
9c96033c | 5880 | return true; |
5881 | ||
5882 | case FOR_STMT: | |
2055d27a | 5883 | if (!RECUR (FOR_INIT_STMT (t), any)) |
9c96033c | 5884 | return false; |
10811950 | 5885 | tmp = FOR_COND (t); |
5886 | if (!RECUR (tmp, rval)) | |
9c96033c | 5887 | return false; |
10811950 | 5888 | if (tmp) |
5889 | { | |
5890 | if (!processing_template_decl) | |
5891 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
f807ff66 | 5892 | /* If we couldn't evaluate the condition, it might not ever be |
5893 | true. */ | |
5894 | if (!integer_onep (tmp)) | |
10811950 | 5895 | return true; |
5896 | } | |
2055d27a | 5897 | if (!RECUR (FOR_EXPR (t), any)) |
9c96033c | 5898 | return false; |
2055d27a | 5899 | if (!RECUR (FOR_BODY (t), any)) |
9c96033c | 5900 | return false; |
32fee334 | 5901 | if (breaks (jump_target) || continues (jump_target)) |
5902 | *jump_target = NULL_TREE; | |
9c96033c | 5903 | return true; |
5904 | ||
33603066 | 5905 | case RANGE_FOR_STMT: |
f4416678 | 5906 | if (!RECUR (RANGE_FOR_INIT_STMT (t), any)) |
5907 | return false; | |
33603066 | 5908 | if (!RECUR (RANGE_FOR_EXPR (t), any)) |
5909 | return false; | |
5910 | if (!RECUR (RANGE_FOR_BODY (t), any)) | |
5911 | return false; | |
32fee334 | 5912 | if (breaks (jump_target) || continues (jump_target)) |
5913 | *jump_target = NULL_TREE; | |
33603066 | 5914 | return true; |
5915 | ||
9c96033c | 5916 | case WHILE_STMT: |
10811950 | 5917 | tmp = WHILE_COND (t); |
5918 | if (!RECUR (tmp, rval)) | |
9c96033c | 5919 | return false; |
10811950 | 5920 | if (!processing_template_decl) |
5921 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
f807ff66 | 5922 | /* If we couldn't evaluate the condition, it might not ever be true. */ |
5923 | if (!integer_onep (tmp)) | |
10811950 | 5924 | return true; |
2055d27a | 5925 | if (!RECUR (WHILE_BODY (t), any)) |
9c96033c | 5926 | return false; |
32fee334 | 5927 | if (breaks (jump_target) || continues (jump_target)) |
5928 | *jump_target = NULL_TREE; | |
9c96033c | 5929 | return true; |
5930 | ||
5931 | case SWITCH_STMT: | |
2055d27a | 5932 | if (!RECUR (SWITCH_STMT_COND (t), rval)) |
9c96033c | 5933 | return false; |
748c426a | 5934 | /* FIXME we don't check SWITCH_STMT_BODY currently, because even |
5935 | unreachable labels would be checked. */ | |
9c96033c | 5936 | return true; |
5937 | ||
da7981e0 | 5938 | case STMT_EXPR: |
2055d27a | 5939 | return RECUR (STMT_EXPR_STMT (t), rval); |
da7981e0 | 5940 | |
09b42213 | 5941 | case LAMBDA_EXPR: |
27db1f50 | 5942 | if (cxx_dialect >= cxx17) |
5943 | /* In C++17 lambdas can be constexpr, don't give up yet. */ | |
5944 | return true; | |
5945 | else if (flags & tf_error) | |
5946 | error_at (loc, "lambda-expression is not a constant expression " | |
5947 | "before C++17"); | |
5948 | return false; | |
5949 | ||
09b42213 | 5950 | case DYNAMIC_CAST_EXPR: |
5951 | case PSEUDO_DTOR_EXPR: | |
09b42213 | 5952 | case NEW_EXPR: |
5953 | case VEC_NEW_EXPR: | |
5954 | case DELETE_EXPR: | |
5955 | case VEC_DELETE_EXPR: | |
5956 | case THROW_EXPR: | |
d6a08f5c | 5957 | case OMP_PARALLEL: |
5958 | case OMP_TASK: | |
5959 | case OMP_FOR: | |
83728168 | 5960 | case OMP_SIMD: |
d6a08f5c | 5961 | case OMP_DISTRIBUTE: |
5962 | case OMP_TASKLOOP: | |
5963 | case OMP_TEAMS: | |
5964 | case OMP_TARGET_DATA: | |
5965 | case OMP_TARGET: | |
5966 | case OMP_SECTIONS: | |
5967 | case OMP_ORDERED: | |
5968 | case OMP_CRITICAL: | |
5969 | case OMP_SINGLE: | |
5970 | case OMP_SECTION: | |
5971 | case OMP_MASTER: | |
5972 | case OMP_TASKGROUP: | |
5973 | case OMP_TARGET_UPDATE: | |
5974 | case OMP_TARGET_ENTER_DATA: | |
5975 | case OMP_TARGET_EXIT_DATA: | |
09b42213 | 5976 | case OMP_ATOMIC: |
5977 | case OMP_ATOMIC_READ: | |
5978 | case OMP_ATOMIC_CAPTURE_OLD: | |
5979 | case OMP_ATOMIC_CAPTURE_NEW: | |
7e5a76c8 | 5980 | case OMP_DEPOBJ: |
d6a08f5c | 5981 | case OACC_PARALLEL: |
5982 | case OACC_KERNELS: | |
5983 | case OACC_DATA: | |
5984 | case OACC_HOST_DATA: | |
5985 | case OACC_LOOP: | |
5986 | case OACC_CACHE: | |
5987 | case OACC_DECLARE: | |
5988 | case OACC_ENTER_DATA: | |
5989 | case OACC_EXIT_DATA: | |
5990 | case OACC_UPDATE: | |
09b42213 | 5991 | /* GCC internal stuff. */ |
5992 | case VA_ARG_EXPR: | |
09b42213 | 5993 | case TRANSACTION_EXPR: |
9c96033c | 5994 | case ASM_EXPR: |
9abecca2 | 5995 | case AT_ENCODE_EXPR: |
9c96033c | 5996 | fail: |
09b42213 | 5997 | if (flags & tf_error) |
d6a08f5c | 5998 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 5999 | return false; |
6000 | ||
bb6e576c | 6001 | case OBJ_TYPE_REF: |
6002 | if (cxx_dialect >= cxx2a) | |
6003 | /* In C++2a virtual calls can be constexpr, don't give up yet. */ | |
6004 | return true; | |
6005 | else if (flags & tf_error) | |
6006 | error_at (loc, "virtual functions cannot be constexpr before C++2a"); | |
6007 | return false; | |
6008 | ||
09b42213 | 6009 | case TYPEID_EXPR: |
6010 | /* -- a typeid expression whose operand is of polymorphic | |
6011 | class type; */ | |
6012 | { | |
6013 | tree e = TREE_OPERAND (t, 0); | |
6014 | if (!TYPE_P (e) && !type_dependent_expression_p (e) | |
6015 | && TYPE_POLYMORPHIC_P (TREE_TYPE (e))) | |
6016 | { | |
6017 | if (flags & tf_error) | |
d6a08f5c | 6018 | error_at (loc, "typeid-expression is not a constant expression " |
6019 | "because %qE is of polymorphic type", e); | |
09b42213 | 6020 | return false; |
6021 | } | |
6022 | return true; | |
6023 | } | |
6024 | ||
57e83b58 | 6025 | case POINTER_DIFF_EXPR: |
09b42213 | 6026 | case MINUS_EXPR: |
09b42213 | 6027 | want_rval = true; |
6028 | goto binary; | |
6029 | ||
6030 | case LT_EXPR: | |
6031 | case LE_EXPR: | |
6032 | case GT_EXPR: | |
6033 | case GE_EXPR: | |
6034 | case EQ_EXPR: | |
6035 | case NE_EXPR: | |
09b42213 | 6036 | want_rval = true; |
6037 | goto binary; | |
6038 | ||
9c96033c | 6039 | case PREINCREMENT_EXPR: |
6040 | case POSTINCREMENT_EXPR: | |
6041 | case PREDECREMENT_EXPR: | |
6042 | case POSTDECREMENT_EXPR: | |
6043 | if (cxx_dialect < cxx14) | |
6044 | goto fail; | |
6045 | goto unary; | |
6046 | ||
09b42213 | 6047 | case BIT_NOT_EXPR: |
6048 | /* A destructor. */ | |
6049 | if (TYPE_P (TREE_OPERAND (t, 0))) | |
6050 | return true; | |
e3533433 | 6051 | /* fall through. */ |
09b42213 | 6052 | |
09b42213 | 6053 | case CONJ_EXPR: |
6054 | case SAVE_EXPR: | |
6055 | case FIX_TRUNC_EXPR: | |
6056 | case FLOAT_EXPR: | |
6057 | case NEGATE_EXPR: | |
6058 | case ABS_EXPR: | |
1c67942e | 6059 | case ABSU_EXPR: |
09b42213 | 6060 | case TRUTH_NOT_EXPR: |
6061 | case FIXED_CONVERT_EXPR: | |
6062 | case UNARY_PLUS_EXPR: | |
6fdf70f5 | 6063 | case UNARY_LEFT_FOLD_EXPR: |
6064 | case UNARY_RIGHT_FOLD_EXPR: | |
9c96033c | 6065 | unary: |
2055d27a | 6066 | return RECUR (TREE_OPERAND (t, 0), rval); |
09b42213 | 6067 | |
6068 | case CAST_EXPR: | |
6069 | case CONST_CAST_EXPR: | |
6070 | case STATIC_CAST_EXPR: | |
6071 | case REINTERPRET_CAST_EXPR: | |
6072 | case IMPLICIT_CONV_EXPR: | |
6073 | if (cxx_dialect < cxx11 | |
6074 | && !dependent_type_p (TREE_TYPE (t)) | |
6075 | && !INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t))) | |
6076 | /* In C++98, a conversion to non-integral type can't be part of a | |
6077 | constant expression. */ | |
6078 | { | |
6079 | if (flags & tf_error) | |
d6a08f5c | 6080 | error_at (loc, |
6081 | "cast to non-integral type %qT in a constant expression", | |
6082 | TREE_TYPE (t)); | |
09b42213 | 6083 | return false; |
6084 | } | |
e0ccd480 | 6085 | /* This might be a conversion from a class to a (potentially) literal |
6086 | type. Let's consider it potentially constant since the conversion | |
6087 | might be a constexpr user-defined conversion. */ | |
6088 | else if (cxx_dialect >= cxx11 | |
6089 | && (dependent_type_p (TREE_TYPE (t)) | |
6090 | || !COMPLETE_TYPE_P (TREE_TYPE (t)) | |
6091 | || literal_type_p (TREE_TYPE (t))) | |
6092 | && TREE_OPERAND (t, 0)) | |
6093 | { | |
6094 | tree type = TREE_TYPE (TREE_OPERAND (t, 0)); | |
6095 | /* If this is a dependent type, it could end up being a class | |
6096 | with conversions. */ | |
6097 | if (type == NULL_TREE || WILDCARD_TYPE_P (type)) | |
6098 | return true; | |
6099 | /* Or a non-dependent class which has conversions. */ | |
6100 | else if (CLASS_TYPE_P (type) | |
6101 | && (TYPE_HAS_CONVERSION (type) || dependent_scope_p (type))) | |
6102 | return true; | |
6103 | } | |
09b42213 | 6104 | |
2055d27a | 6105 | return (RECUR (TREE_OPERAND (t, 0), |
90ad495b | 6106 | !TYPE_REF_P (TREE_TYPE (t)))); |
09b42213 | 6107 | |
9c96033c | 6108 | case BIND_EXPR: |
2055d27a | 6109 | return RECUR (BIND_EXPR_BODY (t), want_rval); |
9c96033c | 6110 | |
9c96033c | 6111 | case CLEANUP_POINT_EXPR: |
6112 | case MUST_NOT_THROW_EXPR: | |
6113 | case TRY_CATCH_EXPR: | |
7f67d68c | 6114 | case TRY_BLOCK: |
9c96033c | 6115 | case EH_SPEC_BLOCK: |
6116 | case EXPR_STMT: | |
09b42213 | 6117 | case PAREN_EXPR: |
6118 | case NON_DEPENDENT_EXPR: | |
6119 | /* For convenience. */ | |
d1980671 | 6120 | case LOOP_EXPR: |
6121 | case EXIT_EXPR: | |
2055d27a | 6122 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 6123 | |
33603066 | 6124 | case DECL_EXPR: |
6125 | tmp = DECL_EXPR_DECL (t); | |
6126 | if (VAR_P (tmp) && !DECL_ARTIFICIAL (tmp)) | |
6127 | { | |
6128 | if (TREE_STATIC (tmp)) | |
6129 | { | |
6130 | if (flags & tf_error) | |
6131 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 6132 | "%<static%> in %<constexpr%> context", tmp); |
33603066 | 6133 | return false; |
6134 | } | |
6135 | else if (CP_DECL_THREAD_LOCAL_P (tmp)) | |
6136 | { | |
6137 | if (flags & tf_error) | |
6138 | error_at (DECL_SOURCE_LOCATION (tmp), "%qD declared " | |
8d6486e1 | 6139 | "%<thread_local%> in %<constexpr%> context", tmp); |
33603066 | 6140 | return false; |
6141 | } | |
282ea908 | 6142 | else if (!check_for_uninitialized_const_var |
6143 | (tmp, /*constexpr_context_p=*/true, flags)) | |
6144 | return false; | |
33603066 | 6145 | } |
6146 | return RECUR (tmp, want_rval); | |
6147 | ||
7f67d68c | 6148 | case TRY_FINALLY_EXPR: |
6149 | return (RECUR (TREE_OPERAND (t, 0), want_rval) | |
6150 | && RECUR (TREE_OPERAND (t, 1), any)); | |
6151 | ||
09b42213 | 6152 | case SCOPE_REF: |
2055d27a | 6153 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 6154 | |
6155 | case TARGET_EXPR: | |
07d8961c | 6156 | if (!TARGET_EXPR_DIRECT_INIT_P (t) |
6157 | && !literal_type_p (TREE_TYPE (t))) | |
09b42213 | 6158 | { |
6159 | if (flags & tf_error) | |
6160 | { | |
bc35ef65 | 6161 | auto_diagnostic_group d; |
d6a08f5c | 6162 | error_at (loc, "temporary of non-literal type %qT in a " |
6163 | "constant expression", TREE_TYPE (t)); | |
09b42213 | 6164 | explain_non_literal_class (TREE_TYPE (t)); |
6165 | } | |
6166 | return false; | |
6167 | } | |
e3533433 | 6168 | /* FALLTHRU */ |
09b42213 | 6169 | case INIT_EXPR: |
2055d27a | 6170 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 6171 | |
6172 | case CONSTRUCTOR: | |
6173 | { | |
6174 | vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); | |
6175 | constructor_elt *ce; | |
6176 | for (i = 0; vec_safe_iterate (v, i, &ce); ++i) | |
2055d27a | 6177 | if (!RECUR (ce->value, want_rval)) |
09b42213 | 6178 | return false; |
6179 | return true; | |
6180 | } | |
6181 | ||
6182 | case TREE_LIST: | |
6183 | { | |
6184 | gcc_assert (TREE_PURPOSE (t) == NULL_TREE | |
6185 | || DECL_P (TREE_PURPOSE (t))); | |
2055d27a | 6186 | if (!RECUR (TREE_VALUE (t), want_rval)) |
09b42213 | 6187 | return false; |
6188 | if (TREE_CHAIN (t) == NULL_TREE) | |
6189 | return true; | |
2055d27a | 6190 | return RECUR (TREE_CHAIN (t), want_rval); |
09b42213 | 6191 | } |
6192 | ||
6193 | case TRUNC_DIV_EXPR: | |
6194 | case CEIL_DIV_EXPR: | |
6195 | case FLOOR_DIV_EXPR: | |
6196 | case ROUND_DIV_EXPR: | |
6197 | case TRUNC_MOD_EXPR: | |
6198 | case CEIL_MOD_EXPR: | |
6199 | case ROUND_MOD_EXPR: | |
6200 | { | |
6201 | tree denom = TREE_OPERAND (t, 1); | |
2055d27a | 6202 | if (!RECUR (denom, rval)) |
09b42213 | 6203 | return false; |
6204 | /* We can't call cxx_eval_outermost_constant_expr on an expression | |
21131a05 | 6205 | that hasn't been through instantiate_non_dependent_expr yet. */ |
09b42213 | 6206 | if (!processing_template_decl) |
6207 | denom = cxx_eval_outermost_constant_expr (denom, true); | |
6208 | if (integer_zerop (denom)) | |
6209 | { | |
6210 | if (flags & tf_error) | |
ea034e2c | 6211 | error ("division by zero is not a constant expression"); |
09b42213 | 6212 | return false; |
6213 | } | |
6214 | else | |
6215 | { | |
6216 | want_rval = true; | |
2055d27a | 6217 | return RECUR (TREE_OPERAND (t, 0), want_rval); |
09b42213 | 6218 | } |
6219 | } | |
6220 | ||
6221 | case COMPOUND_EXPR: | |
6222 | { | |
6223 | /* check_return_expr sometimes wraps a TARGET_EXPR in a | |
6224 | COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR | |
6225 | introduced by build_call_a. */ | |
6226 | tree op0 = TREE_OPERAND (t, 0); | |
6227 | tree op1 = TREE_OPERAND (t, 1); | |
6228 | STRIP_NOPS (op1); | |
6229 | if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) | |
6230 | || TREE_CODE (op1) == EMPTY_CLASS_EXPR) | |
2055d27a | 6231 | return RECUR (op0, want_rval); |
09b42213 | 6232 | else |
6233 | goto binary; | |
6234 | } | |
6235 | ||
6236 | /* If the first operand is the non-short-circuit constant, look at | |
6237 | the second operand; otherwise we only care about the first one for | |
6238 | potentiality. */ | |
6239 | case TRUTH_AND_EXPR: | |
6240 | case TRUTH_ANDIF_EXPR: | |
6241 | tmp = boolean_true_node; | |
6242 | goto truth; | |
6243 | case TRUTH_OR_EXPR: | |
6244 | case TRUTH_ORIF_EXPR: | |
6245 | tmp = boolean_false_node; | |
6246 | truth: | |
6247 | { | |
6248 | tree op = TREE_OPERAND (t, 0); | |
2055d27a | 6249 | if (!RECUR (op, rval)) |
09b42213 | 6250 | return false; |
6251 | if (!processing_template_decl) | |
6252 | op = cxx_eval_outermost_constant_expr (op, true); | |
6253 | if (tree_int_cst_equal (op, tmp)) | |
2055d27a | 6254 | return RECUR (TREE_OPERAND (t, 1), rval); |
09b42213 | 6255 | else |
6256 | return true; | |
6257 | } | |
6258 | ||
6259 | case PLUS_EXPR: | |
6260 | case MULT_EXPR: | |
6261 | case POINTER_PLUS_EXPR: | |
6262 | case RDIV_EXPR: | |
6263 | case EXACT_DIV_EXPR: | |
6264 | case MIN_EXPR: | |
6265 | case MAX_EXPR: | |
6266 | case LSHIFT_EXPR: | |
6267 | case RSHIFT_EXPR: | |
6268 | case LROTATE_EXPR: | |
6269 | case RROTATE_EXPR: | |
6270 | case BIT_IOR_EXPR: | |
6271 | case BIT_XOR_EXPR: | |
6272 | case BIT_AND_EXPR: | |
6273 | case TRUTH_XOR_EXPR: | |
6274 | case UNORDERED_EXPR: | |
6275 | case ORDERED_EXPR: | |
6276 | case UNLT_EXPR: | |
6277 | case UNLE_EXPR: | |
6278 | case UNGT_EXPR: | |
6279 | case UNGE_EXPR: | |
6280 | case UNEQ_EXPR: | |
6281 | case LTGT_EXPR: | |
6282 | case RANGE_EXPR: | |
6283 | case COMPLEX_EXPR: | |
6284 | want_rval = true; | |
6285 | /* Fall through. */ | |
6286 | case ARRAY_REF: | |
6287 | case ARRAY_RANGE_REF: | |
6288 | case MEMBER_REF: | |
6289 | case DOTSTAR_EXPR: | |
f0abe78f | 6290 | case MEM_REF: |
6fdf70f5 | 6291 | case BINARY_LEFT_FOLD_EXPR: |
6292 | case BINARY_RIGHT_FOLD_EXPR: | |
09b42213 | 6293 | binary: |
6294 | for (i = 0; i < 2; ++i) | |
2055d27a | 6295 | if (!RECUR (TREE_OPERAND (t, i), want_rval)) |
09b42213 | 6296 | return false; |
6297 | return true; | |
6298 | ||
09b42213 | 6299 | case VEC_PERM_EXPR: |
6300 | for (i = 0; i < 3; ++i) | |
2055d27a | 6301 | if (!RECUR (TREE_OPERAND (t, i), true)) |
09b42213 | 6302 | return false; |
6303 | return true; | |
6304 | ||
6305 | case COND_EXPR: | |
b0fe8b95 | 6306 | if (COND_EXPR_IS_VEC_DELETE (t)) |
6307 | { | |
6308 | if (flags & tf_error) | |
d6a08f5c | 6309 | error_at (loc, "%<delete[]%> is not a constant expression"); |
b0fe8b95 | 6310 | return false; |
6311 | } | |
6312 | /* Fall through. */ | |
6313 | case IF_STMT: | |
09b42213 | 6314 | case VEC_COND_EXPR: |
6315 | /* If the condition is a known constant, we know which of the legs we | |
6316 | care about; otherwise we only require that the condition and | |
6317 | either of the legs be potentially constant. */ | |
6318 | tmp = TREE_OPERAND (t, 0); | |
2055d27a | 6319 | if (!RECUR (tmp, rval)) |
09b42213 | 6320 | return false; |
6321 | if (!processing_template_decl) | |
6322 | tmp = cxx_eval_outermost_constant_expr (tmp, true); | |
6323 | if (integer_zerop (tmp)) | |
2055d27a | 6324 | return RECUR (TREE_OPERAND (t, 2), want_rval); |
09b42213 | 6325 | else if (TREE_CODE (tmp) == INTEGER_CST) |
2055d27a | 6326 | return RECUR (TREE_OPERAND (t, 1), want_rval); |
09b42213 | 6327 | for (i = 1; i < 3; ++i) |
6328 | if (potential_constant_expression_1 (TREE_OPERAND (t, i), | |
32fee334 | 6329 | want_rval, strict, now, |
6330 | tf_none, jump_target)) | |
09b42213 | 6331 | return true; |
6332 | if (flags & tf_error) | |
d6a08f5c | 6333 | error_at (loc, "expression %qE is not a constant expression", t); |
09b42213 | 6334 | return false; |
6335 | ||
6336 | case VEC_INIT_EXPR: | |
6337 | if (VEC_INIT_EXPR_IS_CONSTEXPR (t)) | |
6338 | return true; | |
6339 | if (flags & tf_error) | |
6340 | { | |
d6a08f5c | 6341 | error_at (loc, "non-constant array initialization"); |
09b42213 | 6342 | diagnose_non_constexpr_vec_init (t); |
6343 | } | |
6344 | return false; | |
6345 | ||
db1ae94f | 6346 | case TYPE_DECL: |
6347 | case TAG_DEFN: | |
6348 | /* We can see these in statement-expressions. */ | |
6349 | return true; | |
6350 | ||
fd130325 | 6351 | case CLEANUP_STMT: |
d2c63826 | 6352 | case EMPTY_CLASS_EXPR: |
38ef3642 | 6353 | case PREDICT_EXPR: |
d2c63826 | 6354 | return false; |
6355 | ||
d1980671 | 6356 | case GOTO_EXPR: |
6357 | { | |
6358 | tree *target = &TREE_OPERAND (t, 0); | |
d40a1eac | 6359 | /* Gotos representing break and continue are OK. */ |
6360 | if (breaks (target) || continues (target)) | |
32fee334 | 6361 | { |
6362 | *jump_target = *target; | |
6363 | return true; | |
6364 | } | |
d40a1eac | 6365 | if (flags & tf_error) |
d6a08f5c | 6366 | error_at (loc, "%<goto%> is not a constant expression"); |
d40a1eac | 6367 | return false; |
d1980671 | 6368 | } |
6369 | ||
24c6ee98 | 6370 | case ANNOTATE_EXPR: |
24c6ee98 | 6371 | return RECUR (TREE_OPERAND (t, 0), rval); |
6372 | ||
09b42213 | 6373 | default: |
6374 | if (objc_is_property_ref (t)) | |
6375 | return false; | |
6376 | ||
6377 | sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t))); | |
d40a1eac | 6378 | gcc_unreachable (); |
09b42213 | 6379 | return false; |
6380 | } | |
2055d27a | 6381 | #undef RECUR |
09b42213 | 6382 | } |
6383 | ||
32fee334 | 6384 | bool |
6385 | potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, | |
6386 | tsubst_flags_t flags) | |
6387 | { | |
6388 | tree target = NULL_TREE; | |
6389 | return potential_constant_expression_1 (t, want_rval, strict, now, | |
6390 | flags, &target); | |
6391 | } | |
6392 | ||
09b42213 | 6393 | /* The main entry point to the above. */ |
6394 | ||
6395 | bool | |
6396 | potential_constant_expression (tree t) | |
6397 | { | |
7e1f8be4 | 6398 | return potential_constant_expression_1 (t, false, true, false, tf_none); |
09b42213 | 6399 | } |
6400 | ||
6401 | /* As above, but require a constant rvalue. */ | |
6402 | ||
6403 | bool | |
6404 | potential_rvalue_constant_expression (tree t) | |
6405 | { | |
7e1f8be4 | 6406 | return potential_constant_expression_1 (t, true, true, false, tf_none); |
09b42213 | 6407 | } |
6408 | ||
6409 | /* Like above, but complain about non-constant expressions. */ | |
6410 | ||
6411 | bool | |
6412 | require_potential_constant_expression (tree t) | |
6413 | { | |
786721dc | 6414 | return potential_constant_expression_1 (t, false, true, false, |
6415 | tf_warning_or_error); | |
09b42213 | 6416 | } |
6417 | ||
6418 | /* Cross product of the above. */ | |
6419 | ||
6420 | bool | |
6421 | require_potential_rvalue_constant_expression (tree t) | |
6422 | { | |
786721dc | 6423 | return potential_constant_expression_1 (t, true, true, false, |
6424 | tf_warning_or_error); | |
6425 | } | |
6426 | ||
6427 | /* Like above, but don't consider PARM_DECL a potential_constant_expression. */ | |
6428 | ||
6429 | bool | |
6430 | require_rvalue_constant_expression (tree t) | |
6431 | { | |
6432 | return potential_constant_expression_1 (t, true, true, true, | |
6433 | tf_warning_or_error); | |
7e1f8be4 | 6434 | } |
6435 | ||
6436 | /* Like potential_constant_expression, but don't consider possible constexpr | |
6437 | substitution of the current function. That is, PARM_DECL qualifies under | |
6438 | potential_constant_expression, but not here. | |
6439 | ||
6440 | This is basically what you can check when any actual constant values might | |
6441 | be value-dependent. */ | |
6442 | ||
6443 | bool | |
6444 | is_constant_expression (tree t) | |
6445 | { | |
6446 | return potential_constant_expression_1 (t, false, true, true, tf_none); | |
6447 | } | |
6448 | ||
6449 | /* Like above, but complain about non-constant expressions. */ | |
6450 | ||
6451 | bool | |
6452 | require_constant_expression (tree t) | |
6453 | { | |
6454 | return potential_constant_expression_1 (t, false, true, true, | |
6455 | tf_warning_or_error); | |
6456 | } | |
6457 | ||
6458 | /* Like is_constant_expression, but allow const variables that are not allowed | |
6459 | under constexpr rules. */ | |
6460 | ||
6461 | bool | |
6462 | is_static_init_expression (tree t) | |
6463 | { | |
6464 | return potential_constant_expression_1 (t, false, false, true, tf_none); | |
09b42213 | 6465 | } |
6466 | ||
29cf24ec | 6467 | /* Returns true if T is a potential constant expression that is not |
6468 | instantiation-dependent, and therefore a candidate for constant folding even | |
6469 | in a template. */ | |
6470 | ||
6471 | bool | |
7e1f8be4 | 6472 | is_nondependent_constant_expression (tree t) |
29cf24ec | 6473 | { |
6474 | return (!type_unknown_p (t) | |
6475 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6476 | && is_constant_expression (t) |
29cf24ec | 6477 | && !instantiation_dependent_expression_p (t)); |
6478 | } | |
6479 | ||
6480 | /* Returns true if T is a potential static initializer expression that is not | |
6481 | instantiation-dependent. */ | |
6482 | ||
6483 | bool | |
7e1f8be4 | 6484 | is_nondependent_static_init_expression (tree t) |
29cf24ec | 6485 | { |
6486 | return (!type_unknown_p (t) | |
6487 | && !BRACE_ENCLOSED_INITIALIZER_P (t) | |
7e1f8be4 | 6488 | && is_static_init_expression (t) |
29cf24ec | 6489 | && !instantiation_dependent_expression_p (t)); |
6490 | } | |
6491 | ||
a050099a | 6492 | /* Finalize constexpr processing after parsing. */ |
6493 | ||
6494 | void | |
6495 | fini_constexpr (void) | |
6496 | { | |
6497 | /* The contexpr call and fundef copies tables are no longer needed. */ | |
6498 | constexpr_call_table = NULL; | |
6499 | fundef_copies_table = NULL; | |
6500 | } | |
6501 | ||
09b42213 | 6502 | #include "gt-cp-constexpr.h" |