| blob | 1084ab1aa013a1f51f03cec977736623730adb8a |
1 /* Handle initialization things in C++.
2 Copyright (C) 1987-2017 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com)
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
21 /* High-level class interface. */
54 /* We are about to generate some complex initialization code.
55 Conceptually, it is all a single expression. However, we may want
56 to include conditionals, loops, and other such statement-level
57 constructs. Therefore, we build the initialization code inside a
58 statement-expression. This function starts such an expression.
59 STMT_EXPR_P and COMPOUND_STMT_P are filled in by this function;
60 pass them back to finish_init_stmts when the expression is
61 complete. */
63 static bool
65 {
72 }
74 /* Finish out the statement-expression begun by the previous call to
75 begin_init_stmts. Returns the statement-expression itself. */
77 static tree
79 {
87 }
89 /* Constructors */
91 /* Called from initialize_vtbl_ptrs via dfs_walk. BINFO is the base
92 which we want to initialize the vtable pointer for, DATA is
93 TREE_LIST whose TREE_VALUE is the this ptr expression. */
95 static tree
97 {
102 {
106 tf_warning_or_error);
109 }
112 }
114 /* Initialize all the vtable pointers in the object pointed to by
115 ADDR. */
117 void
119 {
120 tree list;
121 tree type;
126 /* Walk through the hierarchy, initializing the vptr in each base
127 class. We do these in pre-order because we can't find the virtual
128 bases for a class until we've initialized the vtbl for that
129 class. */
131 }
133 /* Return an expression for the zero-initialization of an object with
134 type T. This expression will either be a constant (in the case
135 that T is a scalar), or a CONSTRUCTOR (in the case that T is an
136 aggregate), or NULL (in the case that T does not require
137 initialization). In either case, the value can be used as
138 DECL_INITIAL for a decl of the indicated TYPE; it is a valid static
139 initializer. If NELTS is non-NULL, and TYPE is an ARRAY_TYPE, NELTS
140 is the number of elements in the array. If STATIC_STORAGE_P is
141 TRUE, initializers are only generated for entities for which
142 zero-initialization does not simply mean filling the storage with
143 zero bytes. FIELD_SIZE, if non-NULL, is the bit size of the field,
144 subfields with bit positions at or above that bit size shouldn't
145 be added. Note that this only works when the result is assigned
146 to a base COMPONENT_REF; if we only have a pointer to the base subobject,
147 expand_assignment will end up clearing the full size of TYPE. */
149 static tree
151 tree field_size)
152 {
155 /* [dcl.init]
157 To zero-initialize an object of type T means:
159 -- if T is a scalar type, the storage is set to the value of zero
160 converted to T.
162 -- if T is a non-union class type, the storage for each nonstatic
163 data member and each base-class subobject is zero-initialized.
165 -- if T is a union type, the storage for its first data member is
166 zero-initialized.
168 -- if T is an array type, the storage for each element is
169 zero-initialized.
171 -- if T is a reference type, no initialization is performed. */
176 ;
178 /* In order to save space, we do not explicitly build initializers
179 for items that do not need them. GCC's semantics are that
180 items with static storage duration that are not otherwise
181 initialized are initialized to zero. */
182 ;
188 {
189 tree field;
192 /* Iterate over the fields, building initializations. */
194 {
201 /* Don't add virtual bases for base classes if they are beyond
202 the size of the current field, that means it is present
203 somewhere else in the object. */
205 {
210 }
212 /* Note that for class types there will be FIELD_DECLs
213 corresponding to base classes as well. Thus, iterating
214 over TYPE_FIELDs will result in correct initialization of
215 all of the subobjects. */
217 {
218 tree new_field_size
225 static_storage_p,
226 new_field_size);
229 }
231 /* For unions, only the first field is initialized. */
234 }
236 /* Build a constructor to contain the initializations. */
238 }
240 {
241 tree max_index;
244 /* Iterate over the array elements, building initializations. */
249 else
252 /* If we have an error_mark here, we should just return error mark
253 as we don't know the size of the array yet. */
258 /* A zero-sized array, which is accepted as an extension, will
259 have an upper bound of -1. */
261 {
262 constructor_elt ce;
264 /* If this is a one element array, we just use a regular init. */
267 else
269 max_index);
275 {
278 }
279 }
281 /* Build a constructor to contain the initializations. */
283 }
286 else
289 /* In all cases, the initializer is a constant. */
294 }
296 /* Return an expression for the zero-initialization of an object with
297 type T. This expression will either be a constant (in the case
298 that T is a scalar), or a CONSTRUCTOR (in the case that T is an
299 aggregate), or NULL (in the case that T does not require
300 initialization). In either case, the value can be used as
301 DECL_INITIAL for a decl of the indicated TYPE; it is a valid static
302 initializer. If NELTS is non-NULL, and TYPE is an ARRAY_TYPE, NELTS
303 is the number of elements in the array. If STATIC_STORAGE_P is
304 TRUE, initializers are only generated for entities for which
305 zero-initialization does not simply mean filling the storage with
306 zero bytes. */
308 tree
310 {
312 }
314 /* Return a suitable initializer for value-initializing an object of type
315 TYPE, as described in [dcl.init]. */
317 tree
319 {
320 /* [dcl.init]
322 To value-initialize an object of type T means:
324 - if T is a class type (clause 9) with either no default constructor
325 (12.1) or a default constructor that is user-provided or deleted,
326 then the object is default-initialized;
328 - if T is a (possibly cv-qualified) class type without a user-provided
329 or deleted default constructor, then the object is zero-initialized
330 and the semantic constraints for default-initialization are checked,
331 and if T has a non-trivial default constructor, the object is
332 default-initialized;
334 - if T is an array type, then each element is value-initialized;
336 - otherwise, the object is zero-initialized.
338 A program that calls for default-initialization or
339 value-initialization of an entity of reference type is ill-formed. */
341 /* The AGGR_INIT_EXPR tweaking below breaks in templates. */
347 {
348 tree ctor =
351 complain);
361 {
362 /* This is a class that needs constructing, but doesn't have
363 a user-provided constructor. So we need to zero-initialize
364 the object and then call the implicitly defined ctor.
365 This will be handled in simplify_aggr_init_expr. */
368 }
369 }
371 /* Discard any access checking during subobject initialization;
372 the checks are implied by the call to the ctor which we have
373 verified is OK (cpp0x/defaulted46.C). */
378 }
380 /* Like build_value_init, but don't call the constructor for TYPE. Used
381 for base initializers. */
383 tree
385 {
387 {
391 }
392 /* FIXME the class and array cases should just use digest_init once it is
393 SFINAE-enabled. */
395 {
400 {
401 tree field;
404 /* Iterate over the fields, building initializations. */
406 {
417 /* We could skip vfields and fields of types with
418 user-defined constructors, but I think that won't improve
419 performance at all; it should be simpler in general just
420 to zero out the entire object than try to only zero the
421 bits that actually need it. */
423 /* Note that for class types there will be FIELD_DECLs
424 corresponding to base classes as well. Thus, iterating
425 over TYPE_FIELDs will result in correct initialization of
426 all of the subobjects. */
435 /* We shouldn't have gotten here for anything that would need
436 non-trivial initialization, and gimplify_init_ctor_preeval
437 would need to be fixed to allow it. */
440 }
442 /* Build a constructor to contain the zero- initializations. */
444 }
445 }
447 {
450 /* Iterate over the array elements, building initializations. */
453 /* If we have an error_mark here, we should just return error mark
454 as we don't know the size of the array yet. */
456 {
459 type);
461 }
464 /* A zero-sized array, which is accepted as an extension, will
465 have an upper bound of -1. */
467 {
468 constructor_elt ce;
470 /* If this is a one element array, we just use a regular init. */
473 else
484 /* We shouldn't have gotten here for anything that would need
485 non-trivial initialization, and gimplify_init_ctor_preeval
486 would need to be fixed to allow it. */
489 }
491 /* Build a constructor to contain the initializations. */
493 }
495 {
499 }
501 {
505 }
508 }
510 /* Initialize current class with INIT, a TREE_LIST of
511 arguments for a target constructor. If TREE_LIST is void_type_node,
512 an empty initializer list was given. */
514 static void
516 {
522 tf_warning_or_error));
524 {
526 LOOKUP_NORMAL
527 |LOOKUP_NONVIRTUAL
533 }
534 }
536 /* Return the non-static data initializer for FIELD_DECL MEMBER. */
540 tree
542 {
543 tree init;
548 {
550 location_t expr_loc
557 /* Check recursive instantiation. */
559 {
564 }
565 else
566 {
579 /* Do deferred instantiation of the NSDMI. */
580 init = (tsubst_copy_and_build
591 {
595 }
599 }
600 }
601 else
605 {
607 {
612 }
614 }
617 {
620 }
621 else
622 {
623 /* Use a PLACEHOLDER_EXPR when we don't have a 'this' parameter to
624 refer to; constexpr evaluation knows what to do with it. */
627 }
629 /* Strip redundant TARGET_EXPR so we don't need to remap it, and
630 so the aggregate init code below will see a CONSTRUCTOR. */
636 /* Now put it back so C++17 copy elision works. */
642 }
644 /* Diagnose the flexible array MEMBER if its INITializer is non-null
645 and return true if so. Otherwise return false. */
647 bool
649 {
657 /* Point at the flexible array member declaration if it's initialized
658 in-class, and at the ctor if it's initialized in a ctor member
659 initializer list. */
660 location_t loc;
662 || !current_function_decl
665 else
670 }
672 /* Initialize MEMBER, a FIELD_DECL, with INIT, a TREE_LIST of
673 arguments. If TREE_LIST is void_type_node, an empty initializer
674 list was given; if NULL_TREE no initializer was given. */
676 static void
678 {
679 tree decl;
682 /* Use the non-static data member initializer if there was no
683 mem-initializer for this field. */
690 /* Effective C++ rule 12 requires that all data members be
691 initialized. */
695 member);
697 /* Get an lvalue for the data member. */
701 tf_warning_or_error);
707 {
709 /* Handle references. */
716 member);
717 }
720 {
721 /* mem() means value-initialization. */
723 {
727 }
728 else
729 {
735 }
736 }
737 /* Deal with this here, as we will get confused if we try to call the
738 assignment op for an anonymous union. This can happen in a
739 synthesized copy constructor. */
741 {
743 {
746 }
747 }
750 /* Pre-digested NSDMI. */
753 /* { } mem-initializer. */
758 {
759 /* With references and list-initialization, we need to deal with
760 extending temporary lifetimes. 12.2p5: "A temporary bound to a
761 reference member in a constructor’s ctor-initializer (12.6.2)
762 persists until the constructor exits." */
767 tf_warning_or_error);
769 {
774 }
777 /* A FIELD_DECL doesn't really have a suitable lifetime, but
778 make_temporary_var_for_ref_to_temp will treat it as automatic and
779 set_up_extended_ref_temp wants to use the decl in a warning. */
789 }
792 {
794 {
796 {
797 /* Check to make sure the member initializer is valid and
798 something like a CONSTRUCTOR in: T a[] = { 1, 2 } and
799 if it isn't, return early to avoid triggering another
800 error below. */
806 else
811 }
815 {
817 {
818 /* Initialize the array only if it's not a flexible
819 array member (i.e., if it has an upper bound). */
823 }
824 }
825 else
827 }
828 else
829 {
836 {
837 /* TYPE_NEEDS_CONSTRUCTING can be set just because we have a
838 vtable; still give this diagnostic. */
843 }
845 tf_warning_or_error));
846 }
847 }
848 else
849 {
851 {
852 tree core_type;
853 /* member traversal: note it leaves init NULL */
855 {
860 }
862 {
867 }
877 }
879 /* There was an explicit member initialization. Do some work
880 in that case. */
882 tf_warning_or_error);
884 /* Reject a member initializer for a flexible array member. */
888 tf_warning_or_error));
889 }
892 {
893 tree expr;
898 tf_warning_or_error);
901 tf_warning_or_error);
906 }
907 }
909 /* Returns a TREE_LIST containing (as the TREE_PURPOSE of each node) all
910 the FIELD_DECLs on the TYPE_FIELDS list for T, in reverse order. */
912 static tree
914 {
915 tree fields;
917 /* Note whether or not T is a union. */
922 {
923 tree fieldtype;
925 /* Skip CONST_DECLs for enumeration constants and so forth. */
931 /* For an anonymous struct or union, we must recursively
932 consider the fields of the anonymous type. They can be
933 directly initialized from the constructor. */
935 {
936 /* Add this field itself. Synthesized copy constructors
937 initialize the entire aggregate. */
939 /* And now add the fields in the anonymous aggregate. */
942 }
943 /* Add this field. */
946 }
949 }
951 /* Return the innermost aggregate scope for FIELD, whether that is
952 the enclosing class or an anonymous aggregate within it. */
954 static tree
956 {
959 else
961 }
963 /* The MEM_INITS are a TREE_LIST. The TREE_PURPOSE of each list gives
964 a FIELD_DECL or BINFO in T that needs initialization. The
965 TREE_VALUE gives the initializer, or list of initializer arguments.
967 Return a TREE_LIST containing all of the initializations required
968 for T, in the order in which they should be performed. The output
969 list has the same format as the input. */
971 static tree
973 {
974 tree init;
976 tree sorted_inits;
977 tree next_subobject;
982 /* Build up a list of initializations. The TREE_PURPOSE of entry
983 will be the subobject (a FIELD_DECL or BINFO) to initialize. The
984 TREE_VALUE will be the constructor arguments, or NULL if no
985 explicit initialization was provided. */
988 /* Process the virtual bases. */
993 /* Process the direct bases. */
999 /* Process the non-static data members. */
1001 /* Reverse the entire list of initializations, so that they are in
1002 the order that they will actually be performed. */
1005 /* If the user presented the initializers in an order different from
1006 that in which they will actually occur, we issue a warning. Keep
1007 track of the next subobject which can be explicitly initialized
1008 without issuing a warning. */
1011 /* Go through the explicit initializers, filling in TREE_PURPOSE in
1012 the SORTED_INITS. */
1014 {
1015 tree subobject;
1016 tree subobject_init;
1020 /* If the explicit initializers are in sorted order, then
1021 SUBOBJECT will be NEXT_SUBOBJECT, or something following
1022 it. */
1024 subobject_init;
1029 /* Issue a warning if the explicit initializer order does not
1030 match that which will actually occur.
1031 ??? Are all these on the correct lines? */
1033 {
1038 else
1044 else
1048 }
1050 /* Look again, from the beginning of the list. */
1052 {
1056 }
1058 /* It is invalid to initialize the same subobject more than
1059 once. */
1061 {
1065 subobject);
1066 else
1069 subobject);
1070 }
1072 /* Record the initialization. */
1075 }
1077 /* [class.base.init]
1079 If a ctor-initializer specifies more than one mem-initializer for
1080 multiple members of the same union (including members of
1081 anonymous unions), the ctor-initializer is ill-formed.
1083 Here we also splice out uninitialized union members. */
1085 {
1089 {
1090 tree field;
1091 tree ctx;
1097 /* Skip base classes. */
1101 /* If this is an anonymous aggregate with no explicit initializer,
1102 splice it out. */
1106 /* See if this field is a member of a union, or a member of a
1107 structure contained in a union, etc. */
1110 /* If this field is not a member of a union, skip it. */
1115 /* If this union member has no explicit initializer and no NSDMI,
1116 splice it out. */
1119 else
1122 /* It's only an error if we have two initializers for the same
1123 union type. */
1125 {
1128 }
1130 /* See if LAST_FIELD and the field initialized by INIT are
1131 members of the same union (or the union itself). If so, there's
1132 a problem, unless they're actually members of the same structure
1133 which is itself a member of a union. For example, given:
1135 union { struct { int i; int j; }; };
1137 initializing both `i' and `j' makes sense. */
1138 ctx = common_enclosing_class
1144 {
1145 /* A mem-initializer hides an NSDMI. */
1150 else
1151 {
1154 ctx);
1156 }
1157 }
1161 next:
1164 splice:
1167 }
1168 }
1171 }
1173 /* Callback for cp_walk_tree to mark all PARM_DECLs in a tree as read. */
1175 static tree
1177 {
1182 }
1184 /* Initialize all bases and members of CURRENT_CLASS_TYPE. MEM_INITS
1185 is a TREE_LIST giving the explicit mem-initializer-list for the
1186 constructor. The TREE_PURPOSE of each entry is a subobject (a
1187 FIELD_DECL or a BINFO) of the CURRENT_CLASS_TYPE. The TREE_VALUE
1188 is a TREE_LIST giving the arguments to the constructor or
1189 void_type_node for an empty list of arguments. */
1191 void
1193 {
1196 /* We will already have issued an error message about the fact that
1197 the type is incomplete. */
1204 {
1205 /* Delegating constructor. */
1209 }
1215 /* Sort the mem-initializers into the order in which the
1216 initializations should be performed. */
1221 /* Initialize base classes. */
1225 {
1229 /* We already have issued an error message. */
1233 /* Suppress access control when calling the inherited ctor. */
1235 && flag_new_inheriting_ctors
1241 {
1242 /* If these initializations are taking place in a copy constructor,
1243 the base class should probably be explicitly initialized if there
1244 is a user-defined constructor in the base class (other than the
1245 default constructor, which will be called anyway). */
1253 }
1255 /* Initialize the base. */
1257 {
1258 tree base_addr;
1264 arguments,
1265 flags,
1266 tf_warning_or_error);
1268 }
1270 /* C++14 DR1658 Means we do not have to construct vbases of
1271 abstract classes. */
1273 else
1274 /* When not constructing vbases of abstract classes, at least mark
1275 the arguments expressions as read to avoid
1276 -Wunused-but-set-parameter false positives. */
1281 }
1284 /* Initialize the vptrs. */
1287 /* Initialize the data members. */
1289 {
1293 }
1294 }
1296 /* Returns the address of the vtable (i.e., the value that should be
1297 assigned to the vptr) for BINFO. */
1299 tree
1301 {
1303 tree vtbl;
1306 /* If this is a virtual primary base, then the vtable we want to store
1307 is that for the base this is being used as the primary base of. We
1308 can't simply skip the initialization, because we may be expanding the
1309 inits of a subobject constructor where the virtual base layout
1310 can be different. */
1314 /* Figure out what vtable BINFO's vtable is based on, and mark it as
1315 used. */
1319 /* Now compute the address to use when initializing the vptr. */
1325 }
1327 /* This code sets up the virtual function tables appropriate for
1328 the pointer DECL. It is a one-ply initialization.
1330 BINFO is the exact type that DECL is supposed to be. In
1331 multiple inheritance, this might mean "C's A" if C : A, B. */
1333 static void
1335 {
1337 tree vtt_index;
1339 /* Compute the initializer for vptr. */
1342 /* We may get this vptr from a VTT, if this is a subobject
1343 constructor or subobject destructor. */
1346 {
1347 tree vtbl2;
1348 tree vtt_parm;
1350 /* Compute the value to use, when there's a VTT. */
1356 /* The actual initializer is the VTT value only in the subobject
1357 constructor. In maybe_clone_body we'll substitute NULL for
1358 the vtt_parm in the case of the non-subobject constructor. */
1360 }
1362 /* Compute the location of the vtpr. */
1367 /* Assign the vtable to the vptr. */
1371 }
1373 /* If an exception is thrown in a constructor, those base classes already
1374 constructed must be destroyed. This function creates the cleanup
1375 for BINFO, which has just been constructed. If FLAG is non-NULL,
1376 it is a DECL which is nonzero when this base needs to be
1377 destroyed. */
1379 static void
1381 {
1382 tree expr;
1387 /* Call the destructor. */
1389 base_dtor_identifier,
1390 NULL,
1391 binfo,
1393 tf_warning_or_error);
1405 }
1407 /* Construct the virtual base-class VBASE passing the ARGUMENTS to its
1408 constructor. */
1410 static void
1412 {
1413 tree inner_if_stmt;
1414 tree exp;
1415 tree flag;
1417 /* If there are virtual base classes with destructors, we need to
1418 emit cleanups to destroy them if an exception is thrown during
1419 the construction process. These exception regions (i.e., the
1420 period during which the cleanups must occur) begin from the time
1421 the construction is complete to the end of the function. If we
1422 create a conditional block in which to initialize the
1423 base-classes, then the cleanup region for the virtual base begins
1424 inside a block, and ends outside of that block. This situation
1425 confuses the sjlj exception-handling code. Therefore, we do not
1426 create a single conditional block, but one for each
1427 initialization. (That way the cleanup regions always begin
1428 in the outer block.) We trust the back end to figure out
1429 that the FLAG will not change across initializations, and
1430 avoid doing multiple tests. */
1435 /* Compute the location of the virtual base. If we're
1436 constructing virtual bases, then we must be the most derived
1437 class. Therefore, we don't have to look up the virtual base;
1438 we already know where it is. */
1447 }
1449 /* Find the context in which this FIELD can be initialized. */
1451 static tree
1453 {
1456 /* Anonymous union members can be initialized in the first enclosing
1457 non-anonymous union context. */
1461 }
1463 /* Function to give error message if member initialization specification
1464 is erroneous. FIELD is the member we decided to initialize.
1465 TYPE is the type for which the initialization is being performed.
1466 FIELD must be a member of TYPE.
1468 MEMBER_NAME is the name of the member. */
1470 static int
1472 {
1476 {
1478 member_name);
1480 }
1482 {
1485 field);
1487 }
1489 {
1493 }
1495 {
1497 member_name);
1499 }
1502 }
1504 /* NAME is a FIELD_DECL, an IDENTIFIER_NODE which names a field, or it
1505 is a _TYPE node or TYPE_DECL which names a base for that type.
1506 Check the validity of NAME, and return either the base _TYPE, base
1507 binfo, or the FIELD_DECL of the member. If NAME is invalid, return
1508 NULL_TREE and issue a diagnostic.
1510 An old style unnamed direct single base construction is permitted,
1511 where NAME is NULL. */
1513 tree
1515 {
1516 tree basetype;
1517 tree field;
1523 {
1524 /* This is an obsolete unnamed base class initializer. The
1525 parser will already have warned about its use. */
1527 {
1530 current_class_type);
1533 basetype = BINFO_TYPE
1538 current_class_type);
1540 }
1541 }
1543 {
1546 }
1549 else
1553 {
1554 tree class_binfo;
1555 tree direct_binfo;
1556 tree virtual_binfo;
1567 /* Look for a direct base. */
1572 /* Look for a virtual base -- unless the direct base is itself
1573 virtual. */
1577 /* [class.base.init]
1579 If a mem-initializer-id is ambiguous because it designates
1580 both a direct non-virtual base class and an inherited virtual
1581 base class, the mem-initializer is ill-formed. */
1583 {
1585 basetype);
1587 }
1590 {
1594 else
1598 }
1601 }
1602 else
1603 {
1606 else
1611 }
1614 }
1616 /* This is like `expand_member_init', only it stores one aggregate
1617 value into another.
1619 INIT comes in two flavors: it is either a value which
1620 is to be stored in EXP, or it is a parameter list
1621 to go to a constructor, which will operate on EXP.
1622 If INIT is not a parameter list for a constructor, then set
1623 LOOKUP_ONLYCONVERTING.
1624 If FLAGS is LOOKUP_ONLYCONVERTING then it is the = init form of
1625 the initializer, if FLAGS is 0, then it is the (init) form.
1626 If `init' is a CONSTRUCTOR, then we emit a warning message,
1627 explaining that such initializations are invalid.
1629 If INIT resolves to a CALL_EXPR which happens to return
1630 something of the type we are looking for, then we know
1631 that we can safely use that call to perform the
1632 initialization.
1634 The virtual function table pointer cannot be set up here, because
1635 we do not really know its type.
1637 This never calls operator=().
1639 When initializing, nothing is CONST.
1641 A default copy constructor may have to be used to perform the
1642 initialization.
1644 A constructor or a conversion operator may have to be used to
1645 perform the initialization, but not both, as it would be ambiguous. */
1647 tree
1649 {
1650 tree stmt_expr;
1651 tree compound_stmt;
1661 location_t init_loc = (init
1669 {
1674 {
1678 {
1679 /* Wrap the initializer in a CONSTRUCTOR so that build_vec_init
1680 recognizes it as direct-initialization. */
1684 }
1685 }
1686 else
1687 {
1688 /* An array may not be initialized use the parenthesized
1689 initialization form -- unless the initializer is "()". */
1691 {
1695 }
1696 /* Must arrange to initialize each element of EXP
1697 from elements of INIT. */
1707 {
1711 else
1713 }
1714 }
1718 from_array,
1719 complain);
1723 /* Restore the type of init unless it was used directly. */
1727 }
1738 /* Just know that we've seen something for this node. */
1752 }
1754 static void
1756 tsubst_flags_t complain)
1757 {
1760 /* It fails because there may not be a constructor which takes
1761 its own type as the first (or only parameter), but which does
1762 take other types via a conversion. So, if the thing initializing
1763 the expression is a unit element of type X, first try X(X&),
1764 followed by initialization by X. If neither of these work
1765 out, then look hard. */
1766 tree rval;
1769 /* If we have direct-initialization from an initializer list, pull
1770 it out of the TREE_LIST so the code below can see it. */
1773 {
1777 /* Only call reshape_init if it has not been called earlier
1778 by the callers. */
1781 }
1785 /* A brace-enclosed initializer for an aggregate. In C++0x this can
1786 happen for direct-initialization, too. */
1789 /* A CONSTRUCTOR of the target's type is a previously digested
1790 initializer, whether that happened just above or in
1791 cp_parser_late_parsing_nsdmi.
1793 A TARGET_EXPR with TARGET_EXPR_DIRECT_INIT_P or TARGET_EXPR_LIST_INIT_P
1794 set represents the whole initialization, so we shouldn't build up
1795 another ctor call. */
1802 {
1803 /* Early initialization via a TARGET_EXPR only works for
1804 complete objects. */
1811 }
1815 {
1816 /* Base subobjects should only get direct-initialization. */
1820 /* Do nothing. We hit this in two cases: Reference initialization,
1821 where we aren't initializing a real variable, so we don't want
1822 to run a new constructor; and catching an exception, where we
1823 have already built up the constructor call so we could wrap it
1825 else
1830 /* We need to protect the initialization of a catch parm with a
1831 call to terminate(), which shows up as a MUST_NOT_THROW_EXPR
1832 around the TARGET_EXPR for the copy constructor. See
1833 initialize_handler_parm. */
1834 {
1838 }
1839 else
1844 }
1849 {
1853 }
1854 else
1859 {
1860 /* Delegating constructor. */
1861 tree complete;
1862 tree base;
1865 /* Unshare the arguments for the second call. */
1868 {
1871 }
1874 complain);
1880 complain);
1883 }
1884 else
1885 {
1890 complain);
1891 }
1897 {
1900 {
1904 }
1905 }
1907 /* FIXME put back convert_to_void? */
1910 }
1912 /* This function is responsible for initializing EXP with INIT
1913 (if any).
1915 BINFO is the binfo of the type for who we are performing the
1916 initialization. For example, if W is a virtual base class of A and B,
1917 and C : A, B.
1918 If we are initializing B, then W must contain B's W vtable, whereas
1919 were we initializing C, W must contain C's W vtable.
1921 TRUE_EXP is nonzero if it is the true expression being initialized.
1922 In this case, it may be EXP, or may just contain EXP. The reason we
1923 need this is because if EXP is a base element of TRUE_EXP, we
1924 don't necessarily know by looking at EXP where its virtual
1925 baseclass fields should really be pointing. But we do know
1926 from TRUE_EXP. In constructors, we don't know anything about
1927 the value being initialized.
1929 FLAGS is just passed to `build_new_method_call'. See that function
1930 for its description. */
1932 static void
1934 tsubst_flags_t complain)
1935 {
1941 /* Use a function returning the desired type to initialize EXP for us.
1942 If the function is a constructor, and its first argument is
1943 NULL_TREE, know that it was meant for us--just slide exp on
1944 in and expand the constructor. Constructors now come
1945 as TARGET_EXPRs. */
1949 {
1951 /* If store_init_value returns NULL_TREE, the INIT has been
1952 recorded as the DECL_INITIAL for EXP. That means there's
1953 nothing more we have to do. */
1959 }
1961 /* List-initialization from {} becomes value-initialization for non-aggregate
1962 classes with default constructors. Handle this here when we're
1963 initializing a base, so protected access works. */
1965 {
1972 }
1974 /* If an explicit -- but empty -- initializer list was present,
1975 that's value-initialization. */
1977 {
1978 /* If the type has data but no user-provided ctor, we need to zero
1979 out the object. */
1982 {
1985 /* Don't clobber already initialized virtual bases. */
1988 field_size);
1991 }
1993 /* If we don't need to mess with the constructor at all,
1994 then we're done. */
1998 /* Otherwise fall through and call the constructor. */
2000 }
2002 /* We know that expand_default_init can handle everything we want
2003 at this point. */
2005 }
2007 /* Report an error if TYPE is not a user-defined, class type. If
2008 OR_ELSE is nonzero, give an error message. */
2010 int
2012 {
2017 {
2021 }
2023 }
2025 tree
2027 {
2033 else
2035 }
2037 /* Build a reference to a member of an aggregate. This is not a C++
2038 `&', but really something which can have its address taken, and
2039 then act as a pointer to member, for example TYPE :: FIELD can have
2040 its address taken by saying & TYPE :: FIELD. ADDRESS_P is true if
2041 this expression is the operand of "&".
2043 @@ Prints out lousy diagnostics for operator <typename>
2044 @@ fields.
2046 @@ This function should be rewritten and placed in search.c. */
2048 tree
2050 tsubst_flags_t complain)
2051 {
2052 tree decl;
2055 /* class templates can come in as TEMPLATE_DECLs here. */
2068 /* Callers should call mark_used before this point. */
2073 {
2077 }
2079 /* Entities other than non-static members need no further
2080 processing. */
2087 {
2091 }
2093 /* Set up BASEBINFO for member lookup. */
2096 /* A lot of this logic is now handled in lookup_member. */
2098 {
2099 /* Go from the TREE_BASELINK to the member function info. */
2103 {
2104 /* Get rid of a potential OVERLOAD around it. */
2107 /* Unique functions are handled easily. */
2109 /* For non-static member of base class, we need a special rule
2110 for access checking [class.protected]:
2112 If the access is to form a pointer to member, the
2113 nested-name-specifier shall name the derived class
2114 (or any class derived from that class). */
2119 complain);
2120 else
2122 complain);
2128 }
2129 else
2131 }
2133 {
2134 /* We need additional test besides the one in
2135 check_accessibility_of_qualified_id in case it is
2136 a pointer to non-static member. */
2138 complain))
2140 }
2143 {
2144 /* If MEMBER is non-static, then the program has fallen afoul of
2145 [expr.prim]:
2147 An id-expression that denotes a nonstatic data member or
2148 nonstatic member function of a class can only be used:
2150 -- as part of a class member access (_expr.ref_) in which the
2151 object-expression refers to the member's class or a class
2152 derived from that class, or
2154 -- to form a pointer to member (_expr.unary.op_), or
2156 -- in the body of a nonstatic member function of that class or
2157 of a class derived from that class (_class.mfct.nonstatic_), or
2159 -- in a mem-initializer for a constructor for that class or for
2160 a class derived from that class (_class.base.init_). */
2162 {
2163 /* Build a representation of the qualified name suitable
2164 for use as the operand to "&" -- even though the "&" is
2165 not actually present. */
2167 /* In Microsoft mode, treat a non-static member function as if
2168 it were a pointer-to-member. */
2170 {
2173 }
2178 }
2180 {
2184 }
2186 }
2191 }
2193 /* If DECL is a scalar enumeration constant or variable with a
2194 constant initializer, return the initializer (or, its initializers,
2195 recursively); otherwise, return DECL. If STRICT_P, the
2196 initializer is only returned if DECL is a
2197 constant-expression. If RETURN_AGGREGATE_CST_OK_P, it is ok to
2198 return an aggregate constant. */
2200 static tree
2202 {
2207 {
2208 tree init;
2209 /* If DECL is a static data member in a template
2210 specialization, we must instantiate it here. The
2211 initializer for the static data member is not processed
2212 until needed; we need it now. */
2216 {
2219 /* Treat the error as a constant to avoid cascading errors on
2220 excessively recursive template instantiation (c++/9335). */
2222 else
2224 }
2225 /* Initializers in templates are generally expanded during
2226 instantiation, so before that for const int i(2)
2227 INIT is a TREE_LIST with the actual initializer as
2228 TREE_VALUE. */
2230 && init
2234 /* Instantiate a non-dependent initializer for user variables. We
2235 mustn't do this for the temporary for an array compound literal;
2236 trying to instatiate the initializer will keep creating new
2237 temporaries until we crash. Probably it's not useful to do it for
2238 other artificial variables, either. */
2244 || (!return_aggregate_cst_ok_p
2245 /* Unless RETURN_AGGREGATE_CST_OK_P is true, do not
2246 return an aggregate constant (of which string
2247 literals are a special case), as we do not want
2248 to make inadvertent copies of such entities, and
2249 we must be sure that their addresses are the
2250 same everywhere. */
2254 /* Don't return a CONSTRUCTOR for a variable with partial run-time
2255 initialization, since it doesn't represent the entire value. */
2259 /* If the variable has a dynamic initializer, don't use its
2260 DECL_INITIAL which doesn't reflect the real value. */
2267 }
2269 }
2271 /* If DECL is a CONST_DECL, or a constant VAR_DECL initialized by constant
2272 of integral or enumeration type, or a constexpr variable of scalar type,
2273 then return that value. These are those variables permitted in constant
2274 expressions by [5.19/1]. */
2276 tree
2278 {
2281 }
2283 /* Like scalar_constant_value, but can also return aggregate initializers. */
2285 tree
2287 {
2290 }
2292 /* A more relaxed version of scalar_constant_value, used by the
2293 common C/C++ code. */
2295 tree
2297 {
2300 }
2301 \f
2302 /* Common subroutines of build_new and build_vec_delete. */
2303 \f
2304 /* Build and return a NEW_EXPR. If NELTS is non-NULL, TYPE[NELTS] is
2305 the type of the object being allocated; otherwise, it's just TYPE.
2306 INIT is the initializer, if any. USE_GLOBAL_NEW is true if the
2307 user explicitly wrote "::operator new". PLACEMENT, if non-NULL, is
2308 a vector of arguments to be provided as arguments to a placement
2309 new operator. This routine performs no semantic checks; it just
2310 creates and returns a NEW_EXPR. */
2312 static tree
2315 {
2316 tree init_list;
2317 tree new_expr;
2319 /* If INIT is NULL, the we want to store NULL_TREE in the NEW_EXPR.
2320 If INIT is not NULL, then we want to store VOID_ZERO_NODE. This
2321 permits us to distinguish the case of a missing initializer "new
2322 int" from an empty initializer "new int()". */
2327 else
2332 init_list);
2337 }
2339 /* Diagnose uninitialized const members or reference members of type
2340 TYPE. USING_NEW is used to disambiguate the diagnostic between a
2341 new expression without a new-initializer and a declaration. Returns
2342 the error count. */
2344 static int
2347 {
2348 tree field;
2355 {
2356 tree field_type;
2367 {
2370 {
2372 {
2376 else
2378 }
2379 else
2380 {
2385 else
2388 }
2391 }
2392 }
2395 {
2398 {
2400 {
2404 else
2406 }
2407 else
2408 {
2413 else
2416 }
2419 }
2420 }
2423 error_count
2426 }
2428 }
2430 int
2432 {
2434 }
2436 /* Call __cxa_bad_array_new_length to indicate that the size calculation
2437 overflowed. Pretend it returns sizetype so that it plays nicely in the
2438 COND_EXPR. */
2440 tree
2442 {
2444 {
2449 fn = push_throw_library_fn
2451 }
2454 }
2456 /* Attempt to find the initializer for field T in the initializer INIT,
2457 when non-null. Returns the initializer when successful and NULL
2458 otherwise. */
2459 static tree
2461 {
2468 /* Iterate over all top-level initializer elements. */
2470 {
2471 /* If the member T is found, return it. */
2475 /* Otherwise continue and/or recurse into nested initializers. */
2479 }
2481 }
2483 /* Attempt to verify that the argument, OPER, of a placement new expression
2484 refers to an object sufficiently large for an object of TYPE or an array
2485 of NELTS of such objects when NELTS is non-null, and issue a warning when
2486 it does not. SIZE specifies the size needed to construct the object or
2487 array and captures the result of NELTS * sizeof (TYPE). (SIZE could be
2488 greater when the array under construction requires a cookie to store
2489 NELTS. GCC's placement new expression stores the cookie when invoking
2490 a user-defined placement new operator function but not the default one.
2491 Placement new expressions with user-defined placement new operator are
2492 not diagnosed since we don't know how they use the buffer (this could
2493 be a future extension). */
2494 static void
2496 {
2499 /* The number of bytes to add to or subtract from the size of the provided
2500 buffer based on an offset into an array or an array element reference.
2501 Although intermediate results may be negative (as in a[3] - 2) the final
2502 result cannot be. */
2504 /* True when the size of the entire destination object should be used
2505 to compute the possibly optimistic estimate of the available space. */
2507 /* True when the reference to the destination buffer is an ADDR_EXPR. */
2512 /* Using a function argument or a (non-array) variable as an argument
2513 to placement new is not checked since it's unknown what it might
2514 point to. */
2520 /* Evaluate any constant expressions. */
2523 /* Handle the common case of array + offset expression when the offset
2524 is a constant. */
2526 {
2527 /* If the offset is comple-time constant, use it to compute a more
2528 accurate estimate of the size of the buffer. Since the operand
2529 of POINTER_PLUS_EXPR is represented as an unsigned type, convert
2530 it to signed first.
2531 Otherwise, use the size of the entire array as an optimistic
2532 estimate (this may lead to false negatives). */
2536 else
2542 }
2547 {
2550 }
2556 {
2557 /* Similar to the offset computed above, see if the array index
2558 is a compile-time constant. If so, and unless the offset was
2559 not a compile-time constant, use the index to determine the
2560 size of the buffer. Otherwise, use the entire array as
2561 an optimistic estimate of the size. */
2565 else
2566 {
2569 }
2572 }
2574 /* Refers to the declared object that constains the subobject referenced
2575 by OPER. When the object is initialized, makes it possible to determine
2576 the actual size of a flexible array member used as the buffer passed
2577 as OPER to placement new. */
2579 /* True when operand is a COMPONENT_REF, to distinguish flexible array
2580 members from arrays of unspecified size. */
2583 /* Descend into a struct or union to find the member whose address
2584 is being used as the argument. */
2586 {
2592 }
2598 {
2599 /* A possibly optimistic estimate of the number of bytes available
2600 in the destination buffer. */
2602 /* True when the estimate above is in fact the exact size
2603 of the destination buffer rather than an estimate. */
2606 /* Treat members of unions and members of structs uniformly, even
2607 though the size of a member of a union may be viewed as extending
2608 to the end of the union itself (it is by __builtin_object_size). */
2612 {
2613 /* Use the size of the entire array object when the expression
2614 refers to a variable or its size depends on an expression
2615 that's not a compile-time constant. */
2618 }
2621 {
2622 /* Use the size of the type of the destination buffer object
2623 as the optimistic estimate of the available space in it. */
2625 }
2627 {
2628 /* Constructing into a buffer provided by the flexible array
2629 member of a declared object (which is permitted as a G++
2630 extension). If the array member has been initialized,
2631 determine its size from the initializer. Otherwise,
2632 the array size is zero. */
2637 }
2638 else
2639 {
2640 /* Bail if neither the size of the object nor its type is known. */
2642 }
2647 {
2648 /* Avoid diagnosing flexible array members (which are accepted
2649 as an extension and diagnosed with -Wpedantic) and zero-length
2650 arrays (also an extension).
2651 Overflowing construction in one-element arrays is diagnosed
2652 only at level 2. */
2660 && !var_decl
2663 }
2665 /* The size of the buffer can only be adjusted down but not up. */
2668 /* Reduce the size of the buffer by the adjustment computed above
2669 from the offset and/or the index into the array. */
2672 else
2675 /* The minimum amount of space needed for the allocation. This
2676 is an optimistic estimate that makes it possible to detect
2677 placement new invocation for some undersize buffers but not
2678 others. */
2688 else
2689 {
2690 /* The type is a VLA. */
2692 }
2695 {
2699 exact_size ?
2700 "placement new constructing an object of type "
2701 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2702 "and size %qwi"
2704 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2708 bytes_avail);
2709 else
2711 exact_size ?
2712 "placement new constructing an array of objects "
2713 "of type %qT and size %qwu in a region of type %qT "
2714 "and size %qwi"
2716 "of type %qT and size %qwu in a region of type %qT "
2719 bytes_avail);
2720 else
2722 exact_size ?
2723 "placement new constructing an object of type %qT "
2724 "and size %qwu in a region of type %qT and size %qwi"
2726 "and size %qwu in a region of type %qT and size "
2729 bytes_avail);
2730 }
2731 }
2732 }
2734 /* True if alignof(T) > __STDCPP_DEFAULT_NEW_ALIGNMENT__. */
2736 bool
2738 {
2741 }
2743 /* Return the alignment we expect malloc to guarantee. This should just be
2744 MALLOC_ABI_ALIGNMENT, but that macro defaults to only BITS_PER_WORD for some
2745 reason, so don't let the threshold be smaller than max_align_t_align. */
2747 unsigned
2749 {
2751 }
2753 /* Determine whether an allocation function is a namespace-scope
2754 non-replaceable placement new function. See DR 1748.
2755 TODO: Enable in all standard modes. */
2756 static bool
2758 {
2760 {
2765 }
2767 }
2769 /* Generate code for a new-expression, including calling the "operator
2770 new" function, initializing the object, and, if an exception occurs
2771 during construction, cleaning up. The arguments are as for
2772 build_raw_new_expr. This may change PLACEMENT and INIT.
2773 TYPE is the type of the object being constructed, possibly an array
2774 of NELTS elements when NELTS is non-null (in "new T[NELTS]", T may
2775 be an array of the form U[inner], with the whole expression being
2776 "new U[NELTS][inner]"). */
2778 static tree
2781 tsubst_flags_t complain)
2782 {
2784 /* True iff this is a call to "operator new[]" instead of just
2785 "operator new". */
2787 /* If ARRAY_P is true, the element type of the array. This is never
2788 an ARRAY_TYPE; for something like "new int[3][4]", the
2789 ELT_TYPE is "int". If ARRAY_P is false, this is the same type as
2790 TYPE. */
2791 tree elt_type;
2792 /* The type of the new-expression. (This type is always a pointer
2793 type.) */
2794 tree pointer_type;
2795 tree non_const_pointer_type;
2796 /* The most significant array bound in int[OUTER_NELTS][inner]. */
2798 /* For arrays with a non-constant number of elements, a bounds checks
2799 on the NELTS parameter to avoid integer overflow at runtime. */
2802 /* Number of the "inner" elements in "new T[OUTER_NELTS][inner]". */
2805 /* Size of the inner array elements (those with constant dimensions). */
2806 offset_int inner_size;
2807 /* The address returned by the call to "operator new". This node is
2808 a VAR_DECL and is therefore reusable. */
2809 tree alloc_node;
2810 tree alloc_fn;
2813 /* If non-NULL, the number of extra bytes to allocate at the
2814 beginning of the storage allocated for an array-new expression in
2815 order to store the number of elements. */
2817 tree placement_first;
2819 /* True if the function we are calling is a placement allocation
2820 function. */
2822 /* True if the storage must be initialized, either by a constructor
2823 or due to an explicit new-initializer. */
2825 /* The address of the thing allocated, not including any cookie. In
2826 particular, if an array cookie is in use, DATA_ADDR is the
2827 address of the first array element. This node is a VAR_DECL, and
2828 is therefore reusable. */
2829 tree data_addr;
2834 {
2837 }
2839 {
2840 /* Transforms new (T[N]) to new T[N]. The former is a GNU
2841 extension for variable N. (This also covers new T where T is
2842 a VLA typedef.) */
2848 }
2850 /* Lots of logic below. depends on whether we have a constant number of
2851 elements, so go ahead and fold it now. */
2855 /* If our base type is an array, then make sure we know how many elements
2856 it has. */
2860 {
2864 {
2869 {
2873 }
2875 }
2876 else
2877 {
2879 {
2883 }
2885 }
2889 inner_nelts_cst,
2890 complain);
2891 }
2894 {
2897 }
2902 /* Warn if we performed the (T[N]) to T[N] transformation and N is
2903 variable. */
2906 {
2908 {
2915 }
2916 else
2918 }
2921 {
2925 }
2933 {
2935 /* A program that calls for default-initialization [...] of an
2936 entity of reference type is ill-formed. */
2940 /* A new-expression that creates an object of type T initializes
2941 that object as follows:
2942 - If the new-initializer is omitted:
2943 -- If T is a (possibly cv-qualified) non-POD class type
2944 (or array thereof), the object is default-initialized (8.5).
2945 [...]
2946 -- Otherwise, the object created has indeterminate
2947 value. If T is a const-qualified type, or a (possibly
2948 cv-qualified) POD class type (or array thereof)
2949 containing (directly or indirectly) a member of
2950 const-qualified type, the program is ill-formed; */
2960 }
2964 {
2968 }
2972 {
2973 /* Maximum available size in bytes. Half of the address space
2974 minus the cookie size. */
2975 offset_int max_size
2977 /* Maximum number of outer elements which can be allocated. */
2978 offset_int max_outer_nelts;
2979 tree max_outer_nelts_tree;
2985 /* Unconditionally subtract the cookie size. This decreases the
2986 maximum object size and is safe even if we choose not to use
2987 a cookie after all. */
2993 {
2997 }
3005 {
3007 {
3008 /* When the array size is constant, check it at compile time
3009 to make sure it doesn't exceed the implementation-defined
3010 maximum, as required by C++ 14 (in C++ 11 this requirement
3011 isn't explicitly stated but it's enforced anyway -- see
3012 grokdeclarator in cp/decl.c). */
3016 }
3017 }
3018 else
3019 {
3020 /* When a runtime check is necessary because the array size
3021 isn't constant, keep only the top-most seven bits (starting
3022 with the most significant non-zero bit) of the maximum size
3023 to compare the array size against, to simplify encoding the
3024 constant maximum size in the instruction stream. */
3031 outer_nelts,
3032 max_outer_nelts_tree);
3033 }
3034 }
3042 /* If PLACEMENT is a single simple pointer type not passed by
3043 reference, prepare to capture it in a temporary variable. Do
3044 this now, since PLACEMENT will change in the calls below. */
3052 /* Allocate the object. */
3053 tree fnname;
3054 tree fns;
3058 member_new_p = !globally_qualified_p
3060 && (array_p
3065 {
3066 /* Use a class-specific operator new. */
3067 /* If a cookie is required, add some extra space. */
3070 else
3071 {
3073 /* No size arithmetic necessary, so the size check is
3074 not needed. */
3077 }
3078 /* Perform the overflow check. */
3085 /* Create the argument list. */
3087 /* Do name-lookup to find the appropriate operator. */
3090 {
3094 }
3096 {
3098 {
3101 }
3103 }
3107 {
3110 alloc_call
3114 /* If no matching function is found and the allocated object type
3115 has new-extended alignment, the alignment argument is removed
3116 from the argument list, and overload resolution is performed
3117 again. */
3120 }
3124 LOOKUP_NORMAL,
3126 }
3127 else
3128 {
3129 /* Use a global operator new. */
3130 /* See if a cookie might be required. */
3132 {
3134 /* No size arithmetic necessary, so the size check is
3135 not needed. */
3138 }
3144 }
3151 /* Now, check to see if this function is actually a placement
3152 allocation function. This can happen even when PLACEMENT is NULL
3153 because we might have something like:
3155 struct S { void* operator new (size_t, int i = 0); };
3157 A call to `new S' will get this allocation function, even though
3158 there is no explicit placement argument. If there is more than
3159 one argument, or there are variable arguments, then this is a
3160 placement allocation function. */
3161 placement_allocation_fn_p
3166 && !placement_allocation_fn_p
3171 {
3174 {
3180 }
3181 }
3183 /* If we found a simple case of PLACEMENT_EXPR above, then copy it
3184 into a temporary variable. */
3190 {
3196 {
3200 }
3204 {
3205 /* Attempt to make the warning point at the operator new argument. */
3210 }
3211 }
3213 /* In the simple case, we can stop now. */
3218 /* Store the result of the allocation call in a variable so that we can
3219 use it more than once. */
3223 /* Strip any COMPOUND_EXPRs from ALLOC_CALL. */
3227 /* Preevaluate the placement args so that we don't reevaluate them for a
3228 placement delete. */
3230 {
3231 tree inits;
3235 alloc_expr);
3236 }
3238 /* unless an allocation function is declared with an empty excep-
3239 tion-specification (_except.spec_), throw(), it indicates failure to
3240 allocate storage by throwing a bad_alloc exception (clause _except_,
3241 _lib.bad.alloc_); it returns a non-null pointer otherwise If the allo-
3242 cation function is declared with an empty exception-specification,
3243 throw(), it returns null to indicate failure to allocate storage and a
3244 non-null pointer otherwise.
3246 So check for a null exception spec on the op new we just called. */
3249 check_new
3253 {
3254 tree cookie;
3255 tree cookie_ptr;
3256 tree size_ptr_type;
3258 /* Adjust so we're pointing to the start of the object. */
3261 /* Store the number of bytes allocated so that we can know how
3262 many elements to destroy later. We use the last sizeof
3263 (size_t) bytes to store the number of elements. */
3274 {
3275 /* Also store the element size. */
3286 }
3287 }
3288 else
3289 {
3292 }
3294 /* Now use a pointer to the type we've actually allocated. */
3296 /* But we want to operate on a non-const version to start with,
3297 since we'll be modifying the elements. */
3298 non_const_pointer_type = build_pointer_type
3302 /* Any further uses of alloc_node will want this type, too. */
3305 /* Now initialize the allocated object. Note that we preevaluate the
3306 initialization expression, apart from the actual constructor call or
3307 assignment--we do this because we want to delay the allocation as long
3308 as possible in order to minimize the size of the exception region for
3309 placement delete. */
3311 {
3316 {
3319 }
3322 {
3323 /* build_value_init doesn't work in templates, and we don't need
3324 the initializer anyway since we're going to throw it away and
3325 rebuild it at instantiation time, so just build up a single
3326 constructor call to get any appropriate diagnostics. */
3330 complete_ctor_identifier,
3332 LOOKUP_NORMAL,
3333 complain);
3335 }
3337 {
3341 {
3345 else
3346 {
3350 complain);
3351 else
3352 /* We'll check the length at runtime. */
3356 }
3357 }
3359 {
3363 else
3366 }
3367 init_expr
3371 integer_one_node,
3372 complain),
3373 vecinit,
3374 explicit_value_init_p,
3376 complain);
3378 /* An array initialization is stable because the initialization
3379 of each element is a full-expression, so the temporaries don't
3380 leak out. */
3382 }
3383 else
3384 {
3388 {
3390 complete_ctor_identifier,
3392 LOOKUP_NORMAL,
3393 complain);
3394 }
3396 {
3397 /* Something like `new int()'. NO_CLEANUP is needed so
3398 we don't try and build a (possibly ill-formed)
3399 destructor. */
3404 }
3405 else
3406 {
3407 tree ie;
3409 /* We are processing something like `new int (10)', which
3410 means allocate an int, and initialize it with 10. */
3413 complain);
3416 }
3417 /* If the initializer uses C++14 aggregate NSDMI that refer to the
3418 object being initialized, replace them now and don't try to
3419 preevaluate. */
3427 stable = (!had_placeholder
3429 }
3434 /* If any part of the object initialization terminates by throwing an
3435 exception and a suitable deallocation function can be found, the
3436 deallocation function is called to free the memory in which the
3437 object was being constructed, after which the exception continues
3438 to propagate in the context of the new-expression. If no
3439 unambiguous matching deallocation function can be found,
3440 propagating the exception does not cause the object's memory to be
3441 freed. */
3443 {
3445 tree cleanup;
3447 /* The Standard is unclear here, but the right thing to do
3448 is to use the same method for finding deallocation
3449 functions that we use for finding allocation functions. */
3450 cleanup = (build_op_delete_call
3452 alloc_node,
3453 size,
3454 globally_qualified_p,
3456 alloc_fn,
3457 complain));
3462 /* This is much simpler if we were able to preevaluate all of
3463 the arguments to the constructor call. */
3464 {
3465 /* CLEANUP is compiler-generated, so no diagnostics. */
3469 /* Likewise, this try-catch is compiler-generated. */
3471 }
3472 else
3473 /* Ack! First we allocate the memory. Then we set our sentry
3474 variable to true, and expand a cleanup that deletes the
3475 memory if sentry is true. Then we run the constructor, and
3476 finally clear the sentry.
3478 We need to do this because we allocate the space first, so
3479 if there are any temporaries with cleanups in the
3480 constructor args and we weren't able to preevaluate them, we
3481 need this EH region to extend until end of full-expression
3482 to preserve nesting. */
3483 {
3491 /* CLEANUP is compiler-generated, so no diagnostics. */
3501 init_expr
3504 end));
3505 /* Likewise, this is compiler-generated. */
3507 }
3508 }
3509 }
3510 else
3513 /* Now build up the return value in reverse order. */
3523 /* If we don't have an initializer or a cookie, strip the TARGET_EXPR
3524 and return the call (which doesn't need to be adjusted). */
3526 else
3527 {
3529 {
3532 nullptr_node,
3533 complain);
3536 }
3538 /* Perform the allocation before anything else, so that ALLOC_NODE
3539 has been initialized before we start using it. */
3541 }
3546 /* A new-expression is never an lvalue. */
3550 }
3552 /* Generate a representation for a C++ "new" expression. *PLACEMENT
3553 is a vector of placement-new arguments (or NULL if none). If NELTS
3554 is NULL, TYPE is the type of the storage to be allocated. If NELTS
3555 is not NULL, then this is an array-new allocation; TYPE is the type
3556 of the elements in the array and NELTS is the number of elements in
3557 the array. *INIT, if non-NULL, is the initializer for the new
3558 object, or an empty vector to indicate an initializer of "()". If
3559 USE_GLOBAL_NEW is true, then the user explicitly wrote "::new"
3560 rather than just "new". This may change PLACEMENT and INIT. */
3562 tree
3565 {
3566 tree rval;
3575 /* Don't do auto deduction where it might affect mangling. */
3577 {
3580 {
3583 {
3586 }
3588 }
3589 }
3592 {
3599 use_global_new);
3604 {
3606 /* Also copy any CONSTRUCTORs in *init, since reshape_init and
3607 digest_init clobber them in place. */
3609 {
3613 }
3614 }
3620 }
3623 {
3625 {
3628 else
3630 }
3632 /* Try to determine the constant value only for the purposes
3633 of the diagnostic below but continue to use the original
3634 value and handle const folding later. */
3637 /* The expression in a noptr-new-declarator is erroneous if it's of
3638 non-class type and its value before converting to std::size_t is
3639 less than zero. ... If the expression is a constant expression,
3640 the program is ill-fomed. */
3643 {
3647 }
3651 }
3653 /* ``A reference cannot be created by the new operator. A reference
3654 is not an object (8.2.2, 8.4.3), so a pointer to it could not be
3655 returned by new.'' ARM 5.3.3 */
3657 {
3660 else
3663 }
3666 {
3670 }
3672 /* The type allocated must be complete. If the new-type-id was
3673 "T[N]" then we are just checking that "T" is complete here, but
3674 that is equivalent, since the value of "N" doesn't matter. */
3683 {
3689 }
3691 /* Wrap it in a NOP_EXPR so warn_if_unused_value doesn't complain. */
3696 }
3697 \f
3698 static tree
3700 special_function_kind auto_delete_vec,
3702 {
3703 tree virtual_size;
3705 tree size_exp;
3707 /* Temporary variables used by the loop. */
3710 /* This is the body of the loop that implements the deletion of a
3711 single element, and moves temp variables to next elements. */
3712 tree body;
3714 /* This is the LOOP_EXPR that governs the deletion of the elements. */
3717 /* This is the thing that governs what to do after the loop has run. */
3720 /* This is the BIND_EXPR which holds the outermost iterator of the
3721 loop. It is convenient to set this variable up and test it before
3722 executing any other code in the loop.
3723 This is also the containing expression returned by this function. */
3725 tree tmp;
3727 /* We should only have 1-D arrays here. */
3734 {
3737 "possible problem detected in invocation of "
3739 {
3742 "class-specific operator delete [] will be called, "
3744 }
3745 /* This size won't actually be used. */
3748 }
3755 {
3756 /* Make sure the destructor is callable. */
3758 {
3761 complain);
3764 }
3766 }
3768 /* The below is short by the cookie size. */
3773 tbase_init
3777 base),
3778 virtual_size),
3779 complain);
3797 complain);
3805 no_destructor:
3806 /* Delete the storage if appropriate. */
3808 {
3809 tree base_tbd;
3811 /* The below is short by the cookie size. */
3816 /* no header */
3818 else
3819 {
3820 tree cookie_size;
3824 MINUS_EXPR,
3827 cookie_size,
3828 complain);
3832 /* True size with header. */
3834 }
3841 complain);
3842 }
3846 ;
3849 else
3850 /* The delete operator mist be called, even if a destructor
3851 throws. */
3857 /* Outermost wrapper: If pointer is null, punt. */
3860 /* This is a compiler generated comparison, don't emit
3861 e.g. -Wnonnull-compare warning for it. */
3869 {
3872 }
3875 /* Pre-evaluate the SAVE_EXPR outside of the BIND_EXPR. */
3879 }
3881 /* Create an unnamed variable of the indicated TYPE. */
3883 tree
3885 {
3886 tree decl;
3896 }
3898 /* Create a new temporary variable of the indicated TYPE, initialized
3899 to INIT.
3901 It is not entered into current_binding_level, because that breaks
3902 things when it comes time to do final cleanups (which take place
3903 "outside" the binding contour of the function). */
3905 tree
3907 {
3908 tree decl;
3917 }
3919 /* Subroutine of build_vec_init. Returns true if assigning to an array of
3920 INNER_ELT_TYPE from INIT is trivial. */
3922 static bool
3924 {
3929 }
3931 /* Subroutine of build_vec_init: Check that the array has at least N
3932 elements. Other parameters are local variables in build_vec_init. */
3934 void
3936 {
3939 {
3941 {
3943 nelts);
3947 }
3948 /* Don't check an array new when -fno-exceptions. */
3949 }
3952 {
3953 /* Make sure the last element of the initializer is in bounds. */
3954 finish_expr_stmt
3955 (ubsan_instrument_bounds
3957 }
3958 }
3960 /* `build_vec_init' returns tree structure that performs
3961 initialization of a vector of aggregate types.
3963 BASE is a reference to the vector, of ARRAY_TYPE, or a pointer
3964 to the first element, of POINTER_TYPE.
3965 MAXINDEX is the maximum index of the array (one less than the
3966 number of elements). It is only used if BASE is a pointer or
3967 TYPE_DOMAIN (TREE_TYPE (BASE)) == NULL_TREE.
3969 INIT is the (possibly NULL) initializer.
3971 If EXPLICIT_VALUE_INIT_P is true, then INIT must be NULL. All
3972 elements in the array are value-initialized.
3974 FROM_ARRAY is 0 if we should init everything with INIT
3975 (i.e., every element initialized from INIT).
3976 FROM_ARRAY is 1 if we should index into INIT in parallel
3977 with initialization of DECL.
3978 FROM_ARRAY is 2 if we should index into INIT in parallel,
3979 but use assignment instead of initialization. */
3981 tree
3985 {
3986 tree rval;
3989 tree iterator;
3990 /* The type of BASE. */
3992 /* The type of an element in the array. */
3994 /* The element type reached after removing all outer array
3995 types. */
3996 tree inner_elt_type;
3997 /* The type of a pointer to an element in the array. */
3998 tree ptype;
3999 tree stmt_expr;
4000 tree compound_stmt;
4023 /* Look through the TARGET_EXPR around a compound literal. */
4032 {
4035 {
4038 }
4039 }
4041 /* If we have a braced-init-list or string constant, make sure that the array
4042 is big enough for all the initializers. */
4057 || (same_type_ignoring_top_level_qualifiers_p
4059 /* Don't do this if the CONSTRUCTOR might contain something
4060 that might throw and require us to clean up. */
4064 {
4065 /* Do non-default initialization of trivial arrays resulting from
4066 brace-enclosed initializers. In this case, digest_init and
4067 store_constructor will handle the semantics for us. */
4073 }
4079 {
4085 }
4086 else
4089 /* The code we are generating looks like:
4090 ({
4091 T* t1 = (T*) base;
4092 T* rval = t1;
4093 ptrdiff_t iterator = maxindex;
4094 try {
4095 for (; iterator != -1; --iterator) {
4096 ... initialize *t1 ...
4097 ++t1;
4098 }
4099 } catch (...) {
4100 ... destroy elements that were constructed ...
4101 }
4102 rval;
4103 })
4105 We can omit the try and catch blocks if we know that the
4106 initialization will never throw an exception, or if the array
4107 elements do not have destructors. We can omit the loop completely if
4108 the elements of the array do not have constructors.
4110 We actually wrap the entire body of the above in a STMT_EXPR, for
4111 tidiness.
4113 When copying from array to another, when the array elements have
4114 only trivial copy constructors, we should use __builtin_memcpy
4115 rather than generating a loop. That way, we could take advantage
4116 of whatever cleverness the back end has for dealing with copies
4117 of blocks of memory. */
4126 /* If initializing one array from another, initialize element by
4127 element. We rely upon the below calls to do the argument
4128 checking. Evaluate the initializer before entering the try block. */
4130 {
4139 }
4141 /* Protect the entire array initialization so that we can destroy
4142 the partially constructed array if an exception is thrown.
4143 But don't do this if we're assigning. */
4146 {
4148 }
4150 /* Should we try to create a constant initializer? */
4154 : (type_has_constexpr_default_constructor
4160 /* If we're initializing a static array, we want to do static
4161 initialization of any elements with constant initializers even if
4162 some are non-constant. */
4168 /* Skip over the handling of non-empty init lists. */
4171 /* Maybe pull out constant value when from_array? */
4174 {
4175 /* Do non-default initialization of non-trivial arrays resulting from
4176 brace-enclosed initializers. */
4179 /* If the constructor already has the array type, it's been through
4180 digest_init, so we shouldn't try to do anything more. */
4191 {
4193 tree one_init;
4195 num_initialized_elts++;
4202 else
4208 {
4211 {
4215 else
4217 }
4218 else
4219 {
4221 {
4226 }
4228 }
4229 }
4236 complain);
4239 else
4243 complain);
4246 else
4248 }
4250 /* Any elements without explicit initializers get T{}. */
4252 }
4254 {
4255 /* Check that the array is at least as long as the string. */
4262 /* Copy the string to the first part of the array. */
4268 /* Adjust the counter and pointer. */
4277 /* And set the rest of the array to NUL. */
4280 }
4282 {
4287 {
4291 }
4292 }
4294 /* Now, default-initialize any remaining elements. We don't need to
4295 do that if a) the type does not need constructing, or b) we've
4296 already initialized all the elements.
4298 We do need to keep going if we're copying an array. */
4301 /* With a constexpr default constructor, which we checked for when
4302 setting try_const above, default-initialization is equivalent to
4303 value-initialization, and build_value_init gives us something more
4304 friendly to maybe_constant_init. */
4309 && (num_initialized_elts
4311 {
4312 /* If the ITERATOR is lesser or equal to -1, then we don't have to loop;
4313 we've already initialized all the elements. */
4314 tree for_stmt;
4315 tree elt_init;
4316 tree to;
4324 complain);
4331 /* If the initializer is {}, then all elements are initialized from T{}.
4332 But for non-classes, that's the same as value-initialization. */
4334 {
4336 {
4338 }
4339 else
4340 {
4343 }
4344 }
4347 {
4348 tree from;
4351 {
4357 }
4358 else
4368 complain);
4369 else
4371 }
4373 {
4375 sorry
4379 explicit_value_init_p,
4381 }
4383 {
4387 }
4388 else
4389 {
4393 else
4394 {
4397 complain);
4399 }
4400 }
4406 {
4407 /* FIXME refs to earlier elts */
4410 {
4412 /* Don't fill the CONSTRUCTOR with zeros. */
4416 }
4417 else
4418 {
4422 else
4424 }
4427 {
4430 {
4433 }
4434 }
4435 }
4443 complain));
4446 complain));
4449 }
4451 /* Make sure to cleanup any partially constructed elements. */
4454 {
4455 tree e;
4458 complain);
4460 /* Flatten multi-dimensional array since build_vec_delete only
4461 expects one-dimensional array. */
4465 /* Avoid mixing signed and unsigned. */
4468 complain);
4477 }
4479 /* The value of the array initialization is the array itself, RVAL
4480 is a pointer to the first element. */
4491 {
4493 {
4496 }
4499 else
4501 }
4503 /* Now make the result have the correct type. */
4505 {
4510 }
4513 }
4515 /* Call the DTOR_KIND destructor for EXP. FLAGS are as for
4516 build_delete. */
4518 static tree
4520 tsubst_flags_t complain)
4521 {
4522 tree name;
4523 tree fn;
4525 {
4540 }
4545 flags,
4547 complain);
4548 }
4550 /* Generate a call to a destructor. TYPE is the type to cast ADDR to.
4551 ADDR is an expression which yields the store to be destroyed.
4552 AUTO_DELETE is the name of the destructor to call, i.e., either
4553 sfk_complete_destructor, sfk_base_destructor, or
4554 sfk_deleting_destructor.
4556 FLAGS is the logical disjunction of zero or more LOOKUP_
4557 flags. See cp-tree.h for more info. */
4559 tree
4562 {
4563 tree expr;
4570 /* Can happen when CURRENT_EXCEPTION_OBJECT gets its type
4571 set to `error_mark_node' before it gets properly cleaned up. */
4579 {
4581 {
4585 }
4588 }
4591 {
4594 /* We don't want to warn about delete of void*, only other
4595 incomplete types. Deleting other incomplete types
4596 invokes undefined behavior, but it is not ill-formed, so
4597 compile to something that would even do The Right Thing
4598 (TM) should the type have a trivial dtor and no delete
4599 operator. */
4601 {
4604 {
4607 "possible problem detected in invocation of "
4609 {
4612 "neither the destructor nor the class-specific "
4613 "operator delete will be called, even if they are "
4615 }
4616 }
4620 {
4623 {
4626 "deleting object of abstract class type %qT"
4627 " which has non-virtual destructor"
4629 else
4631 "deleting object of polymorphic class type %qT"
4632 " which has non-virtual destructor"
4634 }
4635 }
4636 }
4640 /* Throw away const and volatile on target type of addr. */
4642 }
4643 else
4644 {
4645 /* Don't check PROTECT here; leave that decision to the
4646 destructor. If the destructor is accessible, call it,
4647 else report error. */
4655 }
4658 {
4659 /* Make sure the destructor is callable. */
4661 {
4666 }
4673 use_global_delete,
4676 complain);
4677 }
4678 else
4679 {
4682 tree ifexp;
4687 /* For `::delete x', we must not use the deleting destructor
4688 since then we would not be sure to get the global `operator
4689 delete'. */
4691 {
4692 /* We will use ADDR multiple times so we must save it. */
4695 /* Delete the object. */
4697 head,
4702 complain);
4703 /* Otherwise, treat this like a complete object destructor
4704 call. */
4706 }
4707 /* If the destructor is non-virtual, there is no deleting
4708 variant. Instead, we must explicitly call the appropriate
4709 `operator delete' here. */
4712 {
4713 /* We will use ADDR multiple times so we must save it. */
4715 /* Build the call. */
4717 addr,
4722 complain);
4723 /* Call the complete object destructor. */
4725 }
4728 {
4729 /* Make sure we have access to the member op delete, even though
4730 we'll actually be calling it from the destructor. */
4735 complain);
4736 }
4743 /* The delete operator must be called, regardless of whether
4744 the destructor throws.
4746 [expr.delete]/7 The deallocation function is called
4747 regardless of whether the destructor for the object or some
4748 element of the array throws an exception. */
4751 /* We need to calculate this before the dtor changes the vptr. */
4756 /* Explicit destructor call; don't check for null pointer. */
4758 else
4759 {
4760 /* Handle deleting a null pointer. */
4766 /* This is a compiler generated comparison, don't emit
4767 e.g. -Wnonnull-compare warning for it. */
4770 }
4776 }
4777 }
4779 /* At the beginning of a destructor, push cleanups that will call the
4780 destructors for our base classes and members.
4782 Called from begin_destructor_body. */
4784 void
4786 {
4789 tree member;
4790 tree expr;
4793 /* Run destructors for all virtual baseclasses. */
4796 {
4797 tree cond = (condition_conversion
4799 current_in_charge_parm,
4800 integer_two_node)));
4802 /* The CLASSTYPE_VBASECLASSES vector is in initialization
4803 order, which is also the right order for pushing cleanups. */
4806 {
4808 {
4810 base_dtor_identifier,
4811 NULL,
4812 base_binfo,
4813 (LOOKUP_NORMAL
4815 tf_warning_or_error);
4817 {
4821 }
4822 }
4823 }
4824 }
4826 /* Take care of the remaining baseclasses. */
4829 {
4835 base_dtor_identifier,
4838 tf_warning_or_error);
4841 }
4843 /* Don't automatically destroy union members. */
4849 {
4858 {
4859 tree this_member = (build_class_member_access_expr
4863 tf_warning_or_error));
4865 sfk_complete_destructor,
4870 }
4871 }
4872 }
4874 /* Build a C++ vector delete expression.
4875 MAXINDEX is the number of elements to be deleted.
4876 ELT_SIZE is the nominal size of each element in the vector.
4877 BASE is the expression that should yield the store to be deleted.
4878 This function expands (or synthesizes) these calls itself.
4879 AUTO_DELETE_VEC says whether the container (vector) should be deallocated.
4881 This also calls delete for virtual baseclasses of elements of the vector.
4883 Update: MAXINDEX is no longer needed. The size can be extracted from the
4884 start of the vector for pointers, and from the type for arrays. We still
4885 use MAXINDEX for arrays because it happens to already have one of the
4886 values we'd have to extract. (We could use MAXINDEX with pointers to
4887 confirm the size, and trap if the numbers differ; not clear that it'd
4888 be worth bothering.) */
4890 tree
4892 special_function_kind auto_delete_vec,
4894 {
4895 tree type;
4896 tree rval;
4902 {
4903 /* Step back one from start of vector, and read dimension. */
4904 tree cookie_addr;
4909 {
4912 }
4917 cookie_addr);
4919 }
4921 {
4922 /* Get the total number of things in the array, maxindex is a
4923 bad name. */
4930 {
4933 }
4934 }
4935 else
4936 {
4940 }
4948 }