| blob | acf9c9b7c32f3e79fa3b717066dbe4dd36793076 |
1 /* Handle initialization things in C++.
2 Copyright (C) 1987-2018 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 ;
190 {
191 tree field;
194 /* Iterate over the fields, building initializations. */
196 {
203 /* Don't add virtual bases for base classes if they are beyond
204 the size of the current field, that means it is present
205 somewhere else in the object. */
207 {
212 }
214 /* Note that for class types there will be FIELD_DECLs
215 corresponding to base classes as well. Thus, iterating
216 over TYPE_FIELDs will result in correct initialization of
217 all of the subobjects. */
219 {
220 tree new_field_size
227 static_storage_p,
228 new_field_size);
231 }
233 /* For unions, only the first field is initialized. */
236 }
238 /* Build a constructor to contain the initializations. */
240 }
242 {
243 tree max_index;
246 /* Iterate over the array elements, building initializations. */
251 else
254 /* If we have an error_mark here, we should just return error mark
255 as we don't know the size of the array yet. */
260 /* A zero-sized array, which is accepted as an extension, will
261 have an upper bound of -1. */
263 {
264 constructor_elt ce;
266 /* If this is a one element array, we just use a regular init. */
269 else
271 max_index);
277 {
280 }
281 }
283 /* Build a constructor to contain the initializations. */
285 }
288 else
289 {
292 }
294 /* In all cases, the initializer is a constant. */
299 }
301 /* Return an expression for the zero-initialization of an object with
302 type T. This expression will either be a constant (in the case
303 that T is a scalar), or a CONSTRUCTOR (in the case that T is an
304 aggregate), or NULL (in the case that T does not require
305 initialization). In either case, the value can be used as
306 DECL_INITIAL for a decl of the indicated TYPE; it is a valid static
307 initializer. If NELTS is non-NULL, and TYPE is an ARRAY_TYPE, NELTS
308 is the number of elements in the array. If STATIC_STORAGE_P is
309 TRUE, initializers are only generated for entities for which
310 zero-initialization does not simply mean filling the storage with
311 zero bytes. */
313 tree
315 {
317 }
319 /* Return a suitable initializer for value-initializing an object of type
320 TYPE, as described in [dcl.init]. */
322 tree
324 {
325 /* [dcl.init]
327 To value-initialize an object of type T means:
329 - if T is a class type (clause 9) with either no default constructor
330 (12.1) or a default constructor that is user-provided or deleted,
331 then the object is default-initialized;
333 - if T is a (possibly cv-qualified) class type without a user-provided
334 or deleted default constructor, then the object is zero-initialized
335 and the semantic constraints for default-initialization are checked,
336 and if T has a non-trivial default constructor, the object is
337 default-initialized;
339 - if T is an array type, then each element is value-initialized;
341 - otherwise, the object is zero-initialized.
343 A program that calls for default-initialization or
344 value-initialization of an entity of reference type is ill-formed. */
346 /* The AGGR_INIT_EXPR tweaking below breaks in templates. */
352 {
353 tree ctor =
356 complain);
366 {
367 /* This is a class that needs constructing, but doesn't have
368 a user-provided constructor. So we need to zero-initialize
369 the object and then call the implicitly defined ctor.
370 This will be handled in simplify_aggr_init_expr. */
373 }
374 }
376 /* Discard any access checking during subobject initialization;
377 the checks are implied by the call to the ctor which we have
378 verified is OK (cpp0x/defaulted46.C). */
383 }
385 /* Like build_value_init, but don't call the constructor for TYPE. Used
386 for base initializers. */
388 tree
390 {
392 {
396 }
397 /* FIXME the class and array cases should just use digest_init once it is
398 SFINAE-enabled. */
400 {
405 {
406 tree field;
409 /* Iterate over the fields, building initializations. */
411 {
422 /* We could skip vfields and fields of types with
423 user-defined constructors, but I think that won't improve
424 performance at all; it should be simpler in general just
425 to zero out the entire object than try to only zero the
426 bits that actually need it. */
428 /* Note that for class types there will be FIELD_DECLs
429 corresponding to base classes as well. Thus, iterating
430 over TYPE_FIELDs will result in correct initialization of
431 all of the subobjects. */
440 /* We shouldn't have gotten here for anything that would need
441 non-trivial initialization, and gimplify_init_ctor_preeval
442 would need to be fixed to allow it. */
445 }
447 /* Build a constructor to contain the zero- initializations. */
449 }
450 }
452 {
455 /* Iterate over the array elements, building initializations. */
458 /* If we have an error_mark here, we should just return error mark
459 as we don't know the size of the array yet. */
461 {
464 type);
466 }
469 /* A zero-sized array, which is accepted as an extension, will
470 have an upper bound of -1. */
472 {
473 constructor_elt ce;
475 /* If this is a one element array, we just use a regular init. */
478 else
489 /* We shouldn't have gotten here for anything that would need
490 non-trivial initialization, and gimplify_init_ctor_preeval
491 would need to be fixed to allow it. */
494 }
496 /* Build a constructor to contain the initializations. */
498 }
500 {
504 }
506 {
510 }
513 }
515 /* Initialize current class with INIT, a TREE_LIST of
516 arguments for a target constructor. If TREE_LIST is void_type_node,
517 an empty initializer list was given. */
519 static void
521 {
527 tf_warning_or_error));
529 {
531 LOOKUP_NORMAL
532 |LOOKUP_NONVIRTUAL
538 }
539 }
541 /* Return the non-static data initializer for FIELD_DECL MEMBER. */
545 tree
547 {
548 tree init;
553 {
555 location_t expr_loc
562 /* Check recursive instantiation. */
564 {
569 }
570 else
571 {
582 {
586 }
594 /* Do deferred instantiation of the NSDMI. */
595 init = (tsubst_copy_and_build
606 {
610 }
613 {
616 }
620 }
621 }
622 else
626 {
628 {
633 }
635 }
638 {
641 }
642 else
643 {
644 /* Use a PLACEHOLDER_EXPR when we don't have a 'this' parameter to
645 refer to; constexpr evaluation knows what to do with it. */
648 }
650 /* Strip redundant TARGET_EXPR so we don't need to remap it, and
651 so the aggregate init code below will see a CONSTRUCTOR. */
657 /* Now put it back so C++17 copy elision works. */
663 }
665 /* Diagnose the flexible array MEMBER if its INITializer is non-null
666 and return true if so. Otherwise return false. */
668 bool
670 {
678 /* Point at the flexible array member declaration if it's initialized
679 in-class, and at the ctor if it's initialized in a ctor member
680 initializer list. */
681 location_t loc;
683 || !current_function_decl
686 else
691 }
693 /* If INIT's value can come from a call to std::initializer_list<T>::begin,
694 return that function. Otherwise, NULL_TREE. */
696 static tree
698 {
704 {
712 }
719 }
721 /* If INIT initializing MEMBER is copying the address of the underlying array
722 of an initializer_list, warn. */
724 static void
726 {
747 "initializing %qD from %qE does not extend the lifetime "
749 }
751 /* Initialize MEMBER, a FIELD_DECL, with INIT, a TREE_LIST of
752 arguments. If TREE_LIST is void_type_node, an empty initializer
753 list was given; if NULL_TREE no initializer was given. */
755 static void
757 {
758 tree decl;
761 /* Use the non-static data member initializer if there was no
762 mem-initializer for this field. */
769 /* Effective C++ rule 12 requires that all data members be
770 initialized. */
774 member);
776 /* Get an lvalue for the data member. */
780 tf_warning_or_error);
786 {
788 /* Handle references. */
795 member);
796 }
799 {
800 /* mem() means value-initialization. */
802 {
806 }
807 else
808 {
814 }
815 }
816 /* Deal with this here, as we will get confused if we try to call the
817 assignment op for an anonymous union. This can happen in a
818 synthesized copy constructor. */
820 {
822 {
825 }
826 }
829 /* Pre-digested NSDMI. */
832 /* { } mem-initializer. */
837 {
838 /* With references and list-initialization, we need to deal with
839 extending temporary lifetimes. 12.2p5: "A temporary bound to a
840 reference member in a constructor’s ctor-initializer (12.6.2)
841 persists until the constructor exits." */
846 tf_warning_or_error);
848 {
853 }
856 /* A FIELD_DECL doesn't really have a suitable lifetime, but
857 make_temporary_var_for_ref_to_temp will treat it as automatic and
858 set_up_extended_ref_temp wants to use the decl in a warning. */
868 }
871 {
873 {
875 {
876 /* Check to make sure the member initializer is valid and
877 something like a CONSTRUCTOR in: T a[] = { 1, 2 } and
878 if it isn't, return early to avoid triggering another
879 error below. */
885 else
890 }
894 {
896 {
897 /* Initialize the array only if it's not a flexible
898 array member (i.e., if it has an upper bound). */
902 }
903 }
904 else
906 }
907 else
908 {
915 {
916 /* TYPE_NEEDS_CONSTRUCTING can be set just because we have a
917 vtable; still give this diagnostic. */
922 }
924 tf_warning_or_error));
925 }
926 }
927 else
928 {
930 {
931 tree core_type;
932 /* member traversal: note it leaves init NULL */
934 {
939 }
941 {
946 }
956 }
958 /* There was an explicit member initialization. Do some work
959 in that case. */
961 tf_warning_or_error);
965 /* Reject a member initializer for a flexible array member. */
969 tf_warning_or_error));
970 }
973 {
974 tree expr;
979 tf_warning_or_error);
982 tf_warning_or_error);
987 }
988 }
990 /* Returns a TREE_LIST containing (as the TREE_PURPOSE of each node) all
991 the FIELD_DECLs on the TYPE_FIELDS list for T, in reverse order. */
993 static tree
995 {
996 tree fields;
998 /* Note whether or not T is a union. */
1003 {
1004 tree fieldtype;
1006 /* Skip CONST_DECLs for enumeration constants and so forth. */
1012 /* For an anonymous struct or union, we must recursively
1013 consider the fields of the anonymous type. They can be
1014 directly initialized from the constructor. */
1016 {
1017 /* Add this field itself. Synthesized copy constructors
1018 initialize the entire aggregate. */
1020 /* And now add the fields in the anonymous aggregate. */
1023 }
1024 /* Add this field. */
1027 }
1030 }
1032 /* Return the innermost aggregate scope for FIELD, whether that is
1033 the enclosing class or an anonymous aggregate within it. */
1035 static tree
1037 {
1040 else
1042 }
1044 /* The MEM_INITS are a TREE_LIST. The TREE_PURPOSE of each list gives
1045 a FIELD_DECL or BINFO in T that needs initialization. The
1046 TREE_VALUE gives the initializer, or list of initializer arguments.
1048 Return a TREE_LIST containing all of the initializations required
1049 for T, in the order in which they should be performed. The output
1050 list has the same format as the input. */
1052 static tree
1054 {
1055 tree init;
1057 tree sorted_inits;
1058 tree next_subobject;
1063 /* Build up a list of initializations. The TREE_PURPOSE of entry
1064 will be the subobject (a FIELD_DECL or BINFO) to initialize. The
1065 TREE_VALUE will be the constructor arguments, or NULL if no
1066 explicit initialization was provided. */
1069 /* Process the virtual bases. */
1074 /* Process the direct bases. */
1080 /* Process the non-static data members. */
1082 /* Reverse the entire list of initializations, so that they are in
1083 the order that they will actually be performed. */
1086 /* If the user presented the initializers in an order different from
1087 that in which they will actually occur, we issue a warning. Keep
1088 track of the next subobject which can be explicitly initialized
1089 without issuing a warning. */
1092 /* Go through the explicit initializers, filling in TREE_PURPOSE in
1093 the SORTED_INITS. */
1095 {
1096 tree subobject;
1097 tree subobject_init;
1101 /* If the explicit initializers are in sorted order, then
1102 SUBOBJECT will be NEXT_SUBOBJECT, or something following
1103 it. */
1105 subobject_init;
1110 /* Issue a warning if the explicit initializer order does not
1111 match that which will actually occur.
1112 ??? Are all these on the correct lines? */
1114 {
1119 else
1125 else
1129 }
1131 /* Look again, from the beginning of the list. */
1133 {
1137 }
1139 /* It is invalid to initialize the same subobject more than
1140 once. */
1142 {
1146 subobject);
1147 else
1150 subobject);
1151 }
1153 /* Record the initialization. */
1156 }
1158 /* [class.base.init]
1160 If a ctor-initializer specifies more than one mem-initializer for
1161 multiple members of the same union (including members of
1162 anonymous unions), the ctor-initializer is ill-formed.
1164 Here we also splice out uninitialized union members. */
1166 {
1170 {
1171 tree field;
1172 tree ctx;
1178 /* Skip base classes. */
1182 /* If this is an anonymous aggregate with no explicit initializer,
1183 splice it out. */
1187 /* See if this field is a member of a union, or a member of a
1188 structure contained in a union, etc. */
1191 /* If this field is not a member of a union, skip it. */
1196 /* If this union member has no explicit initializer and no NSDMI,
1197 splice it out. */
1200 else
1203 /* It's only an error if we have two initializers for the same
1204 union type. */
1206 {
1209 }
1211 /* See if LAST_FIELD and the field initialized by INIT are
1212 members of the same union (or the union itself). If so, there's
1213 a problem, unless they're actually members of the same structure
1214 which is itself a member of a union. For example, given:
1216 union { struct { int i; int j; }; };
1218 initializing both `i' and `j' makes sense. */
1219 ctx = common_enclosing_class
1225 {
1226 /* A mem-initializer hides an NSDMI. */
1231 else
1232 {
1235 ctx);
1237 }
1238 }
1242 next:
1245 splice:
1248 }
1249 }
1252 }
1254 /* Callback for cp_walk_tree to mark all PARM_DECLs in a tree as read. */
1256 static tree
1258 {
1263 }
1265 /* Initialize all bases and members of CURRENT_CLASS_TYPE. MEM_INITS
1266 is a TREE_LIST giving the explicit mem-initializer-list for the
1267 constructor. The TREE_PURPOSE of each entry is a subobject (a
1268 FIELD_DECL or a BINFO) of the CURRENT_CLASS_TYPE. The TREE_VALUE
1269 is a TREE_LIST giving the arguments to the constructor or
1270 void_type_node for an empty list of arguments. */
1272 void
1274 {
1277 /* We will already have issued an error message about the fact that
1278 the type is incomplete. */
1285 {
1286 /* Delegating constructor. */
1290 }
1296 /* Sort the mem-initializers into the order in which the
1297 initializations should be performed. */
1302 /* Initialize base classes. */
1306 {
1310 /* We already have issued an error message. */
1314 /* Suppress access control when calling the inherited ctor. */
1316 && flag_new_inheriting_ctors
1322 {
1323 /* If these initializations are taking place in a copy constructor,
1324 the base class should probably be explicitly initialized if there
1325 is a user-defined constructor in the base class (other than the
1326 default constructor, which will be called anyway). */
1334 }
1336 /* Initialize the base. */
1338 {
1339 tree base_addr;
1345 arguments,
1346 flags,
1347 tf_warning_or_error);
1349 }
1351 /* C++14 DR1658 Means we do not have to construct vbases of
1352 abstract classes. */
1354 else
1355 /* When not constructing vbases of abstract classes, at least mark
1356 the arguments expressions as read to avoid
1357 -Wunused-but-set-parameter false positives. */
1362 }
1365 /* Initialize the vptrs. */
1368 /* Initialize the data members. */
1370 {
1374 }
1375 }
1377 /* Returns the address of the vtable (i.e., the value that should be
1378 assigned to the vptr) for BINFO. */
1380 tree
1382 {
1384 tree vtbl;
1387 /* If this is a virtual primary base, then the vtable we want to store
1388 is that for the base this is being used as the primary base of. We
1389 can't simply skip the initialization, because we may be expanding the
1390 inits of a subobject constructor where the virtual base layout
1391 can be different. */
1395 /* Figure out what vtable BINFO's vtable is based on, and mark it as
1396 used. */
1400 /* Now compute the address to use when initializing the vptr. */
1406 }
1408 /* This code sets up the virtual function tables appropriate for
1409 the pointer DECL. It is a one-ply initialization.
1411 BINFO is the exact type that DECL is supposed to be. In
1412 multiple inheritance, this might mean "C's A" if C : A, B. */
1414 static void
1416 {
1418 tree vtt_index;
1420 /* Compute the initializer for vptr. */
1423 /* We may get this vptr from a VTT, if this is a subobject
1424 constructor or subobject destructor. */
1427 {
1428 tree vtbl2;
1429 tree vtt_parm;
1431 /* Compute the value to use, when there's a VTT. */
1437 /* The actual initializer is the VTT value only in the subobject
1438 constructor. In maybe_clone_body we'll substitute NULL for
1439 the vtt_parm in the case of the non-subobject constructor. */
1441 }
1443 /* Compute the location of the vtpr. */
1448 /* Assign the vtable to the vptr. */
1452 }
1454 /* If an exception is thrown in a constructor, those base classes already
1455 constructed must be destroyed. This function creates the cleanup
1456 for BINFO, which has just been constructed. If FLAG is non-NULL,
1457 it is a DECL which is nonzero when this base needs to be
1458 destroyed. */
1460 static void
1462 {
1463 tree expr;
1468 /* Call the destructor. */
1470 base_dtor_identifier,
1471 NULL,
1472 binfo,
1474 tf_warning_or_error);
1486 }
1488 /* Construct the virtual base-class VBASE passing the ARGUMENTS to its
1489 constructor. */
1491 static void
1493 {
1494 tree inner_if_stmt;
1495 tree exp;
1496 tree flag;
1498 /* If there are virtual base classes with destructors, we need to
1499 emit cleanups to destroy them if an exception is thrown during
1500 the construction process. These exception regions (i.e., the
1501 period during which the cleanups must occur) begin from the time
1502 the construction is complete to the end of the function. If we
1503 create a conditional block in which to initialize the
1504 base-classes, then the cleanup region for the virtual base begins
1505 inside a block, and ends outside of that block. This situation
1506 confuses the sjlj exception-handling code. Therefore, we do not
1507 create a single conditional block, but one for each
1508 initialization. (That way the cleanup regions always begin
1509 in the outer block.) We trust the back end to figure out
1510 that the FLAG will not change across initializations, and
1511 avoid doing multiple tests. */
1516 /* Compute the location of the virtual base. If we're
1517 constructing virtual bases, then we must be the most derived
1518 class. Therefore, we don't have to look up the virtual base;
1519 we already know where it is. */
1528 }
1530 /* Find the context in which this FIELD can be initialized. */
1532 static tree
1534 {
1537 /* Anonymous union members can be initialized in the first enclosing
1538 non-anonymous union context. */
1542 }
1544 /* Function to give error message if member initialization specification
1545 is erroneous. FIELD is the member we decided to initialize.
1546 TYPE is the type for which the initialization is being performed.
1547 FIELD must be a member of TYPE.
1549 MEMBER_NAME is the name of the member. */
1551 static int
1553 {
1557 {
1559 member_name);
1561 }
1563 {
1566 field);
1568 }
1570 {
1574 }
1576 {
1578 member_name);
1580 }
1583 }
1585 /* NAME is a FIELD_DECL, an IDENTIFIER_NODE which names a field, or it
1586 is a _TYPE node or TYPE_DECL which names a base for that type.
1587 Check the validity of NAME, and return either the base _TYPE, base
1588 binfo, or the FIELD_DECL of the member. If NAME is invalid, return
1589 NULL_TREE and issue a diagnostic.
1591 An old style unnamed direct single base construction is permitted,
1592 where NAME is NULL. */
1594 tree
1596 {
1597 tree basetype;
1598 tree field;
1604 {
1605 /* This is an obsolete unnamed base class initializer. The
1606 parser will already have warned about its use. */
1608 {
1611 current_class_type);
1614 basetype = BINFO_TYPE
1619 current_class_type);
1621 }
1622 }
1624 {
1627 }
1630 else
1634 {
1635 tree class_binfo;
1636 tree direct_binfo;
1637 tree virtual_binfo;
1648 /* Look for a direct base. */
1653 /* Look for a virtual base -- unless the direct base is itself
1654 virtual. */
1658 /* [class.base.init]
1660 If a mem-initializer-id is ambiguous because it designates
1661 both a direct non-virtual base class and an inherited virtual
1662 base class, the mem-initializer is ill-formed. */
1664 {
1666 basetype);
1668 }
1671 {
1675 else
1679 }
1682 }
1683 else
1684 {
1687 else
1692 }
1695 }
1697 /* This is like `expand_member_init', only it stores one aggregate
1698 value into another.
1700 INIT comes in two flavors: it is either a value which
1701 is to be stored in EXP, or it is a parameter list
1702 to go to a constructor, which will operate on EXP.
1703 If INIT is not a parameter list for a constructor, then set
1704 LOOKUP_ONLYCONVERTING.
1705 If FLAGS is LOOKUP_ONLYCONVERTING then it is the = init form of
1706 the initializer, if FLAGS is 0, then it is the (init) form.
1707 If `init' is a CONSTRUCTOR, then we emit a warning message,
1708 explaining that such initializations are invalid.
1710 If INIT resolves to a CALL_EXPR which happens to return
1711 something of the type we are looking for, then we know
1712 that we can safely use that call to perform the
1713 initialization.
1715 The virtual function table pointer cannot be set up here, because
1716 we do not really know its type.
1718 This never calls operator=().
1720 When initializing, nothing is CONST.
1722 A default copy constructor may have to be used to perform the
1723 initialization.
1725 A constructor or a conversion operator may have to be used to
1726 perform the initialization, but not both, as it would be ambiguous. */
1728 tree
1730 {
1731 tree stmt_expr;
1732 tree compound_stmt;
1742 location_t init_loc = (init
1750 {
1755 {
1760 {
1761 /* Wrap the initializer in a CONSTRUCTOR so that build_vec_init
1762 recognizes it as direct-initialization. */
1766 }
1767 }
1768 else
1769 {
1770 /* Must arrange to initialize each element of EXP
1771 from elements of INIT. */
1780 && (!from_array
1782 /* Can happen, eg, handling the compound-literals
1783 extension (ext/complit12.C). */
1785 {
1790 }
1791 }
1795 from_array,
1796 complain);
1800 /* Restore the type of init unless it was used directly. */
1804 }
1826 /* Just know that we've seen something for this node. */
1830 }
1832 static void
1834 tsubst_flags_t complain)
1835 {
1838 /* It fails because there may not be a constructor which takes
1839 its own type as the first (or only parameter), but which does
1840 take other types via a conversion. So, if the thing initializing
1841 the expression is a unit element of type X, first try X(X&),
1842 followed by initialization by X. If neither of these work
1843 out, then look hard. */
1844 tree rval;
1847 /* If we have direct-initialization from an initializer list, pull
1848 it out of the TREE_LIST so the code below can see it. */
1851 {
1855 /* Only call reshape_init if it has not been called earlier
1856 by the callers. */
1859 }
1863 /* A brace-enclosed initializer for an aggregate. In C++0x this can
1864 happen for direct-initialization, too. */
1867 /* A CONSTRUCTOR of the target's type is a previously digested
1868 initializer, whether that happened just above or in
1869 cp_parser_late_parsing_nsdmi.
1871 A TARGET_EXPR with TARGET_EXPR_DIRECT_INIT_P or TARGET_EXPR_LIST_INIT_P
1872 set represents the whole initialization, so we shouldn't build up
1873 another ctor call. */
1880 {
1881 /* Early initialization via a TARGET_EXPR only works for
1882 complete objects. */
1889 }
1893 {
1894 /* Base subobjects should only get direct-initialization. */
1898 /* Do nothing. We hit this in two cases: Reference initialization,
1899 where we aren't initializing a real variable, so we don't want
1900 to run a new constructor; and catching an exception, where we
1901 have already built up the constructor call so we could wrap it
1903 else
1908 /* We need to protect the initialization of a catch parm with a
1909 call to terminate(), which shows up as a MUST_NOT_THROW_EXPR
1910 around the TARGET_EXPR for the copy constructor. See
1911 initialize_handler_parm. */
1912 {
1916 }
1917 else
1922 }
1927 {
1931 }
1932 else
1937 {
1938 /* Delegating constructor. */
1939 tree complete;
1940 tree base;
1943 /* Unshare the arguments for the second call. */
1946 {
1949 }
1952 complain);
1958 complain);
1961 }
1962 else
1963 {
1968 complain);
1969 }
1975 {
1978 {
1982 }
1983 }
1985 /* FIXME put back convert_to_void? */
1988 }
1990 /* This function is responsible for initializing EXP with INIT
1991 (if any).
1993 BINFO is the binfo of the type for who we are performing the
1994 initialization. For example, if W is a virtual base class of A and B,
1995 and C : A, B.
1996 If we are initializing B, then W must contain B's W vtable, whereas
1997 were we initializing C, W must contain C's W vtable.
1999 TRUE_EXP is nonzero if it is the true expression being initialized.
2000 In this case, it may be EXP, or may just contain EXP. The reason we
2001 need this is because if EXP is a base element of TRUE_EXP, we
2002 don't necessarily know by looking at EXP where its virtual
2003 baseclass fields should really be pointing. But we do know
2004 from TRUE_EXP. In constructors, we don't know anything about
2005 the value being initialized.
2007 FLAGS is just passed to `build_new_method_call'. See that function
2008 for its description. */
2010 static void
2012 tsubst_flags_t complain)
2013 {
2019 /* Use a function returning the desired type to initialize EXP for us.
2020 If the function is a constructor, and its first argument is
2021 NULL_TREE, know that it was meant for us--just slide exp on
2022 in and expand the constructor. Constructors now come
2023 as TARGET_EXPRs. */
2027 {
2029 /* If store_init_value returns NULL_TREE, the INIT has been
2030 recorded as the DECL_INITIAL for EXP. That means there's
2031 nothing more we have to do. */
2037 }
2039 /* List-initialization from {} becomes value-initialization for non-aggregate
2040 classes with default constructors. Handle this here when we're
2041 initializing a base, so protected access works. */
2043 {
2050 }
2052 /* If an explicit -- but empty -- initializer list was present,
2053 that's value-initialization. */
2055 {
2056 /* If the type has data but no user-provided ctor, we need to zero
2057 out the object. */
2060 {
2063 /* Don't clobber already initialized virtual bases. */
2066 field_size);
2069 }
2071 /* If we don't need to mess with the constructor at all,
2072 then we're done. */
2076 /* Otherwise fall through and call the constructor. */
2078 }
2080 /* We know that expand_default_init can handle everything we want
2081 at this point. */
2083 }
2085 /* Report an error if TYPE is not a user-defined, class type. If
2086 OR_ELSE is nonzero, give an error message. */
2088 int
2090 {
2095 {
2099 }
2101 }
2103 tree
2105 {
2111 else
2113 }
2115 /* Build a reference to a member of an aggregate. This is not a C++
2116 `&', but really something which can have its address taken, and
2117 then act as a pointer to member, for example TYPE :: FIELD can have
2118 its address taken by saying & TYPE :: FIELD. ADDRESS_P is true if
2119 this expression is the operand of "&".
2121 @@ Prints out lousy diagnostics for operator <typename>
2122 @@ fields.
2124 @@ This function should be rewritten and placed in search.c. */
2126 tree
2128 tsubst_flags_t complain)
2129 {
2130 tree decl;
2133 /* class templates can come in as TEMPLATE_DECLs here. */
2146 /* Callers should call mark_used before this point. */
2151 {
2155 }
2157 /* Entities other than non-static members need no further
2158 processing. */
2165 {
2169 }
2171 /* Set up BASEBINFO for member lookup. */
2174 /* A lot of this logic is now handled in lookup_member. */
2176 {
2177 /* Go from the TREE_BASELINK to the member function info. */
2181 {
2182 /* Get rid of a potential OVERLOAD around it. */
2185 /* Unique functions are handled easily. */
2187 /* For non-static member of base class, we need a special rule
2188 for access checking [class.protected]:
2190 If the access is to form a pointer to member, the
2191 nested-name-specifier shall name the derived class
2192 (or any class derived from that class). */
2197 complain);
2198 else
2200 complain);
2206 }
2207 else
2209 }
2211 {
2212 /* We need additional test besides the one in
2213 check_accessibility_of_qualified_id in case it is
2214 a pointer to non-static member. */
2216 complain))
2218 }
2221 {
2222 /* If MEMBER is non-static, then the program has fallen afoul of
2223 [expr.prim]:
2225 An id-expression that denotes a nonstatic data member or
2226 nonstatic member function of a class can only be used:
2228 -- as part of a class member access (_expr.ref_) in which the
2229 object-expression refers to the member's class or a class
2230 derived from that class, or
2232 -- to form a pointer to member (_expr.unary.op_), or
2234 -- in the body of a nonstatic member function of that class or
2235 of a class derived from that class (_class.mfct.nonstatic_), or
2237 -- in a mem-initializer for a constructor for that class or for
2238 a class derived from that class (_class.base.init_). */
2240 {
2241 /* Build a representation of the qualified name suitable
2242 for use as the operand to "&" -- even though the "&" is
2243 not actually present. */
2245 /* In Microsoft mode, treat a non-static member function as if
2246 it were a pointer-to-member. */
2248 {
2251 }
2256 }
2258 {
2262 }
2264 }
2269 }
2271 /* If DECL is a scalar enumeration constant or variable with a
2272 constant initializer, return the initializer (or, its initializers,
2273 recursively); otherwise, return DECL. If STRICT_P, the
2274 initializer is only returned if DECL is a
2275 constant-expression. If RETURN_AGGREGATE_CST_OK_P, it is ok to
2276 return an aggregate constant. */
2278 static tree
2280 {
2285 {
2286 tree init;
2287 /* If DECL is a static data member in a template
2288 specialization, we must instantiate it here. The
2289 initializer for the static data member is not processed
2290 until needed; we need it now. */
2294 {
2297 /* Treat the error as a constant to avoid cascading errors on
2298 excessively recursive template instantiation (c++/9335). */
2300 else
2302 }
2303 /* Initializers in templates are generally expanded during
2304 instantiation, so before that for const int i(2)
2305 INIT is a TREE_LIST with the actual initializer as
2306 TREE_VALUE. */
2308 && init
2312 /* Instantiate a non-dependent initializer for user variables. We
2313 mustn't do this for the temporary for an array compound literal;
2314 trying to instatiate the initializer will keep creating new
2315 temporaries until we crash. Probably it's not useful to do it for
2316 other artificial variables, either. */
2322 || (!return_aggregate_cst_ok_p
2323 /* Unless RETURN_AGGREGATE_CST_OK_P is true, do not
2324 return an aggregate constant (of which string
2325 literals are a special case), as we do not want
2326 to make inadvertent copies of such entities, and
2327 we must be sure that their addresses are the
2328 same everywhere. */
2332 /* Don't return a CONSTRUCTOR for a variable with partial run-time
2333 initialization, since it doesn't represent the entire value. */
2337 /* If the variable has a dynamic initializer, don't use its
2338 DECL_INITIAL which doesn't reflect the real value. */
2345 }
2347 }
2349 /* If DECL is a CONST_DECL, or a constant VAR_DECL initialized by constant
2350 of integral or enumeration type, or a constexpr variable of scalar type,
2351 then return that value. These are those variables permitted in constant
2352 expressions by [5.19/1]. */
2354 tree
2356 {
2359 }
2361 /* Like scalar_constant_value, but can also return aggregate initializers. */
2363 tree
2365 {
2368 }
2370 /* A more relaxed version of scalar_constant_value, used by the
2371 common C/C++ code. */
2373 tree
2375 {
2378 }
2379 \f
2380 /* Common subroutines of build_new and build_vec_delete. */
2381 \f
2382 /* Build and return a NEW_EXPR. If NELTS is non-NULL, TYPE[NELTS] is
2383 the type of the object being allocated; otherwise, it's just TYPE.
2384 INIT is the initializer, if any. USE_GLOBAL_NEW is true if the
2385 user explicitly wrote "::operator new". PLACEMENT, if non-NULL, is
2386 a vector of arguments to be provided as arguments to a placement
2387 new operator. This routine performs no semantic checks; it just
2388 creates and returns a NEW_EXPR. */
2390 static tree
2393 {
2394 tree init_list;
2395 tree new_expr;
2397 /* If INIT is NULL, the we want to store NULL_TREE in the NEW_EXPR.
2398 If INIT is not NULL, then we want to store VOID_ZERO_NODE. This
2399 permits us to distinguish the case of a missing initializer "new
2400 int" from an empty initializer "new int()". */
2405 else
2406 {
2411 }
2415 init_list);
2420 }
2422 /* Diagnose uninitialized const members or reference members of type
2423 TYPE. USING_NEW is used to disambiguate the diagnostic between a
2424 new expression without a new-initializer and a declaration. Returns
2425 the error count. */
2427 static int
2430 {
2431 tree field;
2438 {
2439 tree field_type;
2450 {
2453 {
2455 {
2459 else
2461 }
2462 else
2463 {
2468 else
2471 }
2474 }
2475 }
2478 {
2481 {
2483 {
2487 else
2489 }
2490 else
2491 {
2496 else
2499 }
2502 }
2503 }
2506 error_count
2509 }
2511 }
2513 int
2515 {
2517 }
2519 /* Call __cxa_bad_array_new_length to indicate that the size calculation
2520 overflowed. Pretend it returns sizetype so that it plays nicely in the
2521 COND_EXPR. */
2523 tree
2525 {
2527 {
2532 fn = push_throw_library_fn
2534 }
2537 }
2539 /* Attempt to find the initializer for flexible array field T in the
2540 initializer INIT, when non-null. Returns the initializer when
2541 successful and NULL otherwise. */
2542 static tree
2544 {
2551 /* Iterate over all top-level initializer elements. */
2553 /* If the member T is found, return it. */
2558 }
2560 /* Attempt to verify that the argument, OPER, of a placement new expression
2561 refers to an object sufficiently large for an object of TYPE or an array
2562 of NELTS of such objects when NELTS is non-null, and issue a warning when
2563 it does not. SIZE specifies the size needed to construct the object or
2564 array and captures the result of NELTS * sizeof (TYPE). (SIZE could be
2565 greater when the array under construction requires a cookie to store
2566 NELTS. GCC's placement new expression stores the cookie when invoking
2567 a user-defined placement new operator function but not the default one.
2568 Placement new expressions with user-defined placement new operator are
2569 not diagnosed since we don't know how they use the buffer (this could
2570 be a future extension). */
2571 static void
2573 {
2576 /* The number of bytes to add to or subtract from the size of the provided
2577 buffer based on an offset into an array or an array element reference.
2578 Although intermediate results may be negative (as in a[3] - 2) a valid
2579 final result cannot be. */
2581 /* True when the size of the entire destination object should be used
2582 to compute the possibly optimistic estimate of the available space. */
2584 /* True when the reference to the destination buffer is an ADDR_EXPR. */
2589 /* Using a function argument or a (non-array) variable as an argument
2590 to placement new is not checked since it's unknown what it might
2591 point to. */
2597 /* Evaluate any constant expressions. */
2600 /* Handle the common case of array + offset expression when the offset
2601 is a constant. */
2603 {
2604 /* If the offset is compile-time constant, use it to compute a more
2605 accurate estimate of the size of the buffer. Since the operand
2606 of POINTER_PLUS_EXPR is represented as an unsigned type, convert
2607 it to signed first.
2608 Otherwise, use the size of the entire array as an optimistic
2609 estimate (this may lead to false negatives). */
2613 else
2619 }
2624 {
2627 }
2633 {
2634 /* Similar to the offset computed above, see if the array index
2635 is a compile-time constant. If so, and unless the offset was
2636 not a compile-time constant, use the index to determine the
2637 size of the buffer. Otherwise, use the entire array as
2638 an optimistic estimate of the size. */
2642 else
2643 {
2646 }
2649 }
2651 /* Refers to the declared object that constains the subobject referenced
2652 by OPER. When the object is initialized, makes it possible to determine
2653 the actual size of a flexible array member used as the buffer passed
2654 as OPER to placement new. */
2656 /* True when operand is a COMPONENT_REF, to distinguish flexible array
2657 members from arrays of unspecified size. */
2660 /* For COMPONENT_REF (i.e., a struct member) the size of the entire
2661 enclosing struct. Used to validate the adjustment (offset) into
2662 an array at the end of a struct. */
2665 /* Descend into a struct or union to find the member whose address
2666 is being used as the argument. */
2668 {
2677 }
2684 {
2685 /* A possibly optimistic estimate of the number of bytes available
2686 in the destination buffer. */
2688 /* True when the estimate above is in fact the exact size
2689 of the destination buffer rather than an estimate. */
2692 /* Treat members of unions and members of structs uniformly, even
2693 though the size of a member of a union may be viewed as extending
2694 to the end of the union itself (it is by __builtin_object_size). */
2698 {
2699 /* Use the size of the entire array object when the expression
2700 refers to a variable or its size depends on an expression
2701 that's not a compile-time constant. */
2704 }
2706 {
2707 /* Use the size of the type of the destination buffer object
2708 as the optimistic estimate of the available space in it.
2709 Use the maximum possible size for zero-size arrays and
2710 flexible array members (except of initialized objects
2711 thereof). */
2714 }
2717 {
2719 {
2720 /* Constructing into a buffer provided by the flexible array
2721 member of a declared object (which is permitted as a G++
2722 extension). If the array member has been initialized,
2723 determine its size from the initializer. Otherwise,
2724 the array size is zero. */
2728 }
2729 else
2732 }
2737 {
2742 && !var_decl
2745 }
2747 /* Reduce the size of the buffer by the adjustment computed above
2748 from the offset and/or the index into the array. */
2751 else
2752 {
2756 {
2760 }
2761 }
2763 /* The minimum amount of space needed for the allocation. This
2764 is an optimistic estimate that makes it possible to detect
2765 placement new invocation for some undersize buffers but not
2766 others. */
2767 offset_int bytes_need;
2776 else
2777 {
2778 /* The type is a VLA. */
2780 }
2783 {
2787 exact_size ?
2788 "placement new constructing an object of type "
2789 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2790 "and size %qwi"
2792 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2796 else
2798 exact_size ?
2799 "placement new constructing an array of objects "
2800 "of type %qT and size %qwu in a region of type %qT "
2801 "and size %qwi"
2803 "of type %qT and size %qwu in a region of type %qT "
2807 else
2809 exact_size ?
2810 "placement new constructing an object of type %qT "
2811 "and size %qwu in a region of type %qT and size %qwi"
2813 "and size %qwu in a region of type %qT and size "
2817 }
2818 }
2819 }
2821 /* True if alignof(T) > __STDCPP_DEFAULT_NEW_ALIGNMENT__. */
2823 bool
2825 {
2828 }
2830 /* Return the alignment we expect malloc to guarantee. This should just be
2831 MALLOC_ABI_ALIGNMENT, but that macro defaults to only BITS_PER_WORD for some
2832 reason, so don't let the threshold be smaller than max_align_t_align. */
2834 unsigned
2836 {
2838 }
2840 /* Determine whether an allocation function is a namespace-scope
2841 non-replaceable placement new function. See DR 1748.
2842 TODO: Enable in all standard modes. */
2843 static bool
2845 {
2847 {
2852 }
2854 }
2856 /* Generate code for a new-expression, including calling the "operator
2857 new" function, initializing the object, and, if an exception occurs
2858 during construction, cleaning up. The arguments are as for
2859 build_raw_new_expr. This may change PLACEMENT and INIT.
2860 TYPE is the type of the object being constructed, possibly an array
2861 of NELTS elements when NELTS is non-null (in "new T[NELTS]", T may
2862 be an array of the form U[inner], with the whole expression being
2863 "new U[NELTS][inner]"). */
2865 static tree
2868 tsubst_flags_t complain)
2869 {
2871 /* True iff this is a call to "operator new[]" instead of just
2872 "operator new". */
2874 /* If ARRAY_P is true, the element type of the array. This is never
2875 an ARRAY_TYPE; for something like "new int[3][4]", the
2876 ELT_TYPE is "int". If ARRAY_P is false, this is the same type as
2877 TYPE. */
2878 tree elt_type;
2879 /* The type of the new-expression. (This type is always a pointer
2880 type.) */
2881 tree pointer_type;
2882 tree non_const_pointer_type;
2883 /* The most significant array bound in int[OUTER_NELTS][inner]. */
2885 /* For arrays with a non-constant number of elements, a bounds checks
2886 on the NELTS parameter to avoid integer overflow at runtime. */
2889 /* Number of the "inner" elements in "new T[OUTER_NELTS][inner]". */
2892 /* Size of the inner array elements (those with constant dimensions). */
2893 offset_int inner_size;
2894 /* The address returned by the call to "operator new". This node is
2895 a VAR_DECL and is therefore reusable. */
2896 tree alloc_node;
2897 tree alloc_fn;
2900 /* If non-NULL, the number of extra bytes to allocate at the
2901 beginning of the storage allocated for an array-new expression in
2902 order to store the number of elements. */
2904 tree placement_first;
2906 /* True if the function we are calling is a placement allocation
2907 function. */
2909 /* True if the storage must be initialized, either by a constructor
2910 or due to an explicit new-initializer. */
2912 /* The address of the thing allocated, not including any cookie. In
2913 particular, if an array cookie is in use, DATA_ADDR is the
2914 address of the first array element. This node is a VAR_DECL, and
2915 is therefore reusable. */
2916 tree data_addr;
2921 {
2924 }
2926 {
2927 /* Transforms new (T[N]) to new T[N]. The former is a GNU
2928 extension for variable N. (This also covers new T where T is
2929 a VLA typedef.) */
2935 }
2937 /* Lots of logic below depends on whether we have a constant number of
2938 elements, so go ahead and fold it now. */
2941 /* If our base type is an array, then make sure we know how many elements
2942 it has. */
2946 {
2950 {
2955 {
2959 }
2961 }
2962 else
2963 {
2965 {
2969 }
2971 }
2975 inner_nelts_cst,
2976 complain);
2977 }
2980 {
2983 }
2988 /* Warn if we performed the (T[N]) to T[N] transformation and N is
2989 variable. */
2992 {
2994 {
3001 }
3002 else
3004 }
3007 {
3011 }
3015 "%<new%> of initializer_list does not "
3024 {
3026 /* A program that calls for default-initialization [...] of an
3027 entity of reference type is ill-formed. */
3031 /* A new-expression that creates an object of type T initializes
3032 that object as follows:
3033 - If the new-initializer is omitted:
3034 -- If T is a (possibly cv-qualified) non-POD class type
3035 (or array thereof), the object is default-initialized (8.5).
3036 [...]
3037 -- Otherwise, the object created has indeterminate
3038 value. If T is a const-qualified type, or a (possibly
3039 cv-qualified) POD class type (or array thereof)
3040 containing (directly or indirectly) a member of
3041 const-qualified type, the program is ill-formed; */
3051 }
3055 {
3059 }
3063 {
3064 /* Maximum available size in bytes. Half of the address space
3065 minus the cookie size. */
3066 offset_int max_size
3068 /* Maximum number of outer elements which can be allocated. */
3069 offset_int max_outer_nelts;
3070 tree max_outer_nelts_tree;
3076 /* Unconditionally subtract the cookie size. This decreases the
3077 maximum object size and is safe even if we choose not to use
3078 a cookie after all. */
3084 {
3088 }
3096 {
3098 {
3099 /* When the array size is constant, check it at compile time
3100 to make sure it doesn't exceed the implementation-defined
3101 maximum, as required by C++ 14 (in C++ 11 this requirement
3102 isn't explicitly stated but it's enforced anyway -- see
3103 grokdeclarator in cp/decl.c). */
3107 }
3108 }
3109 else
3110 {
3111 /* When a runtime check is necessary because the array size
3112 isn't constant, keep only the top-most seven bits (starting
3113 with the most significant non-zero bit) of the maximum size
3114 to compare the array size against, to simplify encoding the
3115 constant maximum size in the instruction stream. */
3122 outer_nelts,
3123 max_outer_nelts_tree);
3124 }
3125 }
3133 /* If PLACEMENT is a single simple pointer type not passed by
3134 reference, prepare to capture it in a temporary variable. Do
3135 this now, since PLACEMENT will change in the calls below. */
3143 /* Allocate the object. */
3144 tree fnname;
3145 tree fns;
3149 member_new_p = !globally_qualified_p
3151 && (array_p
3156 {
3157 /* Use a class-specific operator new. */
3158 /* If a cookie is required, add some extra space. */
3161 else
3162 {
3164 /* No size arithmetic necessary, so the size check is
3165 not needed. */
3168 }
3169 /* Perform the overflow check. */
3176 /* Create the argument list. */
3178 /* Do name-lookup to find the appropriate operator. */
3181 {
3185 }
3187 {
3189 {
3192 }
3194 }
3198 {
3201 alloc_call
3205 /* If no matching function is found and the allocated object type
3206 has new-extended alignment, the alignment argument is removed
3207 from the argument list, and overload resolution is performed
3208 again. */
3211 }
3215 LOOKUP_NORMAL,
3217 }
3218 else
3219 {
3220 /* Use a global operator new. */
3221 /* See if a cookie might be required. */
3223 {
3225 /* No size arithmetic necessary, so the size check is
3226 not needed. */
3229 }
3235 }
3242 /* Now, check to see if this function is actually a placement
3243 allocation function. This can happen even when PLACEMENT is NULL
3244 because we might have something like:
3246 struct S { void* operator new (size_t, int i = 0); };
3248 A call to `new S' will get this allocation function, even though
3249 there is no explicit placement argument. If there is more than
3250 one argument, or there are variable arguments, then this is a
3251 placement allocation function. */
3252 placement_allocation_fn_p
3257 && !placement_allocation_fn_p
3262 {
3265 {
3271 }
3272 }
3274 /* If we found a simple case of PLACEMENT_EXPR above, then copy it
3275 into a temporary variable. */
3281 {
3287 {
3291 }
3295 {
3296 /* Attempt to make the warning point at the operator new argument. */
3301 }
3302 }
3304 /* In the simple case, we can stop now. */
3309 /* Store the result of the allocation call in a variable so that we can
3310 use it more than once. */
3314 /* Strip any COMPOUND_EXPRs from ALLOC_CALL. */
3318 /* Preevaluate the placement args so that we don't reevaluate them for a
3319 placement delete. */
3321 {
3322 tree inits;
3326 alloc_expr);
3327 }
3329 /* unless an allocation function is declared with an empty excep-
3330 tion-specification (_except.spec_), throw(), it indicates failure to
3331 allocate storage by throwing a bad_alloc exception (clause _except_,
3332 _lib.bad.alloc_); it returns a non-null pointer otherwise If the allo-
3333 cation function is declared with an empty exception-specification,
3334 throw(), it returns null to indicate failure to allocate storage and a
3335 non-null pointer otherwise.
3337 So check for a null exception spec on the op new we just called. */
3340 check_new
3344 {
3345 tree cookie;
3346 tree cookie_ptr;
3347 tree size_ptr_type;
3349 /* Adjust so we're pointing to the start of the object. */
3352 /* Store the number of bytes allocated so that we can know how
3353 many elements to destroy later. We use the last sizeof
3354 (size_t) bytes to store the number of elements. */
3365 {
3366 /* Also store the element size. */
3377 }
3378 }
3379 else
3380 {
3383 }
3385 /* Now use a pointer to the type we've actually allocated. */
3387 /* But we want to operate on a non-const version to start with,
3388 since we'll be modifying the elements. */
3389 non_const_pointer_type = build_pointer_type
3393 /* Any further uses of alloc_node will want this type, too. */
3396 /* Now initialize the allocated object. Note that we preevaluate the
3397 initialization expression, apart from the actual constructor call or
3398 assignment--we do this because we want to delay the allocation as long
3399 as possible in order to minimize the size of the exception region for
3400 placement delete. */
3402 {
3407 {
3410 }
3413 {
3414 /* build_value_init doesn't work in templates, and we don't need
3415 the initializer anyway since we're going to throw it away and
3416 rebuild it at instantiation time, so just build up a single
3417 constructor call to get any appropriate diagnostics. */
3421 complete_ctor_identifier,
3423 LOOKUP_NORMAL,
3424 complain);
3426 }
3428 {
3432 {
3436 else
3437 {
3441 complain);
3442 else
3443 /* We'll check the length at runtime. */
3447 }
3448 }
3450 {
3454 }
3455 init_expr
3459 integer_one_node,
3460 complain),
3461 vecinit,
3462 explicit_value_init_p,
3464 complain);
3466 /* An array initialization is stable because the initialization
3467 of each element is a full-expression, so the temporaries don't
3468 leak out. */
3470 }
3471 else
3472 {
3476 {
3478 complete_ctor_identifier,
3480 LOOKUP_NORMAL,
3481 complain);
3482 }
3484 {
3485 /* Something like `new int()'. NO_CLEANUP is needed so
3486 we don't try and build a (possibly ill-formed)
3487 destructor. */
3492 }
3493 else
3494 {
3495 tree ie;
3497 /* We are processing something like `new int (10)', which
3498 means allocate an int, and initialize it with 10. */
3501 complain);
3504 }
3505 /* If the initializer uses C++14 aggregate NSDMI that refer to the
3506 object being initialized, replace them now and don't try to
3507 preevaluate. */
3515 stable = (!had_placeholder
3517 }
3522 /* If any part of the object initialization terminates by throwing an
3523 exception and a suitable deallocation function can be found, the
3524 deallocation function is called to free the memory in which the
3525 object was being constructed, after which the exception continues
3526 to propagate in the context of the new-expression. If no
3527 unambiguous matching deallocation function can be found,
3528 propagating the exception does not cause the object's memory to be
3529 freed. */
3531 {
3533 tree cleanup;
3535 /* The Standard is unclear here, but the right thing to do
3536 is to use the same method for finding deallocation
3537 functions that we use for finding allocation functions. */
3538 cleanup = (build_op_delete_call
3540 alloc_node,
3541 size,
3542 globally_qualified_p,
3544 alloc_fn,
3545 complain));
3550 /* This is much simpler if we were able to preevaluate all of
3551 the arguments to the constructor call. */
3552 {
3553 /* CLEANUP is compiler-generated, so no diagnostics. */
3557 /* Likewise, this try-catch is compiler-generated. */
3559 }
3560 else
3561 /* Ack! First we allocate the memory. Then we set our sentry
3562 variable to true, and expand a cleanup that deletes the
3563 memory if sentry is true. Then we run the constructor, and
3564 finally clear the sentry.
3566 We need to do this because we allocate the space first, so
3567 if there are any temporaries with cleanups in the
3568 constructor args and we weren't able to preevaluate them, we
3569 need this EH region to extend until end of full-expression
3570 to preserve nesting. */
3571 {
3579 /* CLEANUP is compiler-generated, so no diagnostics. */
3589 init_expr
3592 end));
3593 /* Likewise, this is compiler-generated. */
3595 }
3596 }
3597 }
3598 else
3601 /* Now build up the return value in reverse order. */
3611 /* If we don't have an initializer or a cookie, strip the TARGET_EXPR
3612 and return the call (which doesn't need to be adjusted). */
3614 else
3615 {
3617 {
3620 nullptr_node,
3621 complain);
3624 }
3626 /* Perform the allocation before anything else, so that ALLOC_NODE
3627 has been initialized before we start using it. */
3629 }
3634 /* A new-expression is never an lvalue. */
3638 }
3640 /* Generate a representation for a C++ "new" expression. *PLACEMENT
3641 is a vector of placement-new arguments (or NULL if none). If NELTS
3642 is NULL, TYPE is the type of the storage to be allocated. If NELTS
3643 is not NULL, then this is an array-new allocation; TYPE is the type
3644 of the elements in the array and NELTS is the number of elements in
3645 the array. *INIT, if non-NULL, is the initializer for the new
3646 object, or an empty vector to indicate an initializer of "()". If
3647 USE_GLOBAL_NEW is true, then the user explicitly wrote "::new"
3648 rather than just "new". This may change PLACEMENT and INIT. */
3650 tree
3653 {
3654 tree rval;
3663 /* Don't do auto deduction where it might affect mangling. */
3665 {
3668 {
3671 /* E.g. new auto(x) must have exactly one element, or
3672 a {} initializer will have one element. */
3674 {
3677 }
3678 /* For the rest, e.g. new A(1, 2, 3), create a list. */
3680 {
3682 tree t;
3685 {
3689 }
3690 }
3692 }
3693 }
3696 {
3703 use_global_new);
3708 {
3710 /* Also copy any CONSTRUCTORs in *init, since reshape_init and
3711 digest_init clobber them in place. */
3713 {
3717 }
3718 }
3724 }
3727 {
3729 {
3732 else
3734 }
3736 /* Try to determine the constant value only for the purposes
3737 of the diagnostic below but continue to use the original
3738 value and handle const folding later. */
3741 /* The expression in a noptr-new-declarator is erroneous if it's of
3742 non-class type and its value before converting to std::size_t is
3743 less than zero. ... If the expression is a constant expression,
3744 the program is ill-fomed. */
3747 {
3751 }
3755 }
3757 /* ``A reference cannot be created by the new operator. A reference
3758 is not an object (8.2.2, 8.4.3), so a pointer to it could not be
3759 returned by new.'' ARM 5.3.3 */
3761 {
3764 else
3767 }
3770 {
3774 }
3776 /* The type allocated must be complete. If the new-type-id was
3777 "T[N]" then we are just checking that "T" is complete here, but
3778 that is equivalent, since the value of "N" doesn't matter. */
3787 {
3793 }
3795 /* Wrap it in a NOP_EXPR so warn_if_unused_value doesn't complain. */
3800 }
3801 \f
3802 static tree
3804 special_function_kind auto_delete_vec,
3806 {
3807 tree virtual_size;
3809 tree size_exp;
3811 /* Temporary variables used by the loop. */
3814 /* This is the body of the loop that implements the deletion of a
3815 single element, and moves temp variables to next elements. */
3816 tree body;
3818 /* This is the LOOP_EXPR that governs the deletion of the elements. */
3821 /* This is the thing that governs what to do after the loop has run. */
3824 /* This is the BIND_EXPR which holds the outermost iterator of the
3825 loop. It is convenient to set this variable up and test it before
3826 executing any other code in the loop.
3827 This is also the containing expression returned by this function. */
3829 tree tmp;
3831 /* We should only have 1-D arrays here. */
3838 {
3841 "possible problem detected in invocation of "
3843 {
3846 "class-specific operator delete [] will be called, "
3848 }
3849 /* This size won't actually be used. */
3852 }
3859 {
3860 /* Make sure the destructor is callable. */
3862 {
3865 complain);
3868 }
3870 }
3872 /* The below is short by the cookie size. */
3877 tbase_init
3881 base),
3882 virtual_size),
3883 complain);
3901 complain);
3909 no_destructor:
3910 /* Delete the storage if appropriate. */
3912 {
3913 tree base_tbd;
3915 /* The below is short by the cookie size. */
3920 /* no header */
3922 else
3923 {
3924 tree cookie_size;
3928 MINUS_EXPR,
3931 cookie_size,
3932 complain);
3936 /* True size with header. */
3938 }
3945 complain);
3946 }
3950 ;
3953 else
3954 /* The delete operator mist be called, even if a destructor
3955 throws. */
3961 /* Outermost wrapper: If pointer is null, punt. */
3964 /* This is a compiler generated comparison, don't emit
3965 e.g. -Wnonnull-compare warning for it. */
3973 {
3976 }
3979 /* Pre-evaluate the SAVE_EXPR outside of the BIND_EXPR. */
3983 }
3985 /* Create an unnamed variable of the indicated TYPE. */
3987 tree
3989 {
3990 tree decl;
4000 }
4002 /* Create a new temporary variable of the indicated TYPE, initialized
4003 to INIT.
4005 It is not entered into current_binding_level, because that breaks
4006 things when it comes time to do final cleanups (which take place
4007 "outside" the binding contour of the function). */
4009 tree
4011 {
4012 tree decl;
4021 }
4023 /* Subroutine of build_vec_init. Returns true if assigning to an array of
4024 INNER_ELT_TYPE from INIT is trivial. */
4026 static bool
4028 {
4033 }
4035 /* Subroutine of build_vec_init: Check that the array has at least N
4036 elements. Other parameters are local variables in build_vec_init. */
4038 void
4040 {
4043 {
4045 {
4047 nelts);
4051 }
4052 /* Don't check an array new when -fno-exceptions. */
4053 }
4056 {
4057 /* Make sure the last element of the initializer is in bounds. */
4058 finish_expr_stmt
4059 (ubsan_instrument_bounds
4061 }
4062 }
4064 /* `build_vec_init' returns tree structure that performs
4065 initialization of a vector of aggregate types.
4067 BASE is a reference to the vector, of ARRAY_TYPE, or a pointer
4068 to the first element, of POINTER_TYPE.
4069 MAXINDEX is the maximum index of the array (one less than the
4070 number of elements). It is only used if BASE is a pointer or
4071 TYPE_DOMAIN (TREE_TYPE (BASE)) == NULL_TREE.
4073 INIT is the (possibly NULL) initializer.
4075 If EXPLICIT_VALUE_INIT_P is true, then INIT must be NULL. All
4076 elements in the array are value-initialized.
4078 FROM_ARRAY is 0 if we should init everything with INIT
4079 (i.e., every element initialized from INIT).
4080 FROM_ARRAY is 1 if we should index into INIT in parallel
4081 with initialization of DECL.
4082 FROM_ARRAY is 2 if we should index into INIT in parallel,
4083 but use assignment instead of initialization. */
4085 tree
4089 {
4090 tree rval;
4093 tree iterator;
4094 /* The type of BASE. */
4096 /* The type of an element in the array. */
4098 /* The element type reached after removing all outer array
4099 types. */
4100 tree inner_elt_type;
4101 /* The type of a pointer to an element in the array. */
4102 tree ptype;
4103 tree stmt_expr;
4104 tree compound_stmt;
4127 /* Look through the TARGET_EXPR around a compound literal. */
4136 {
4139 {
4142 }
4143 }
4145 /* If we have a braced-init-list or string constant, make sure that the array
4146 is big enough for all the initializers. */
4161 || (same_type_ignoring_top_level_qualifiers_p
4163 /* Don't do this if the CONSTRUCTOR might contain something
4164 that might throw and require us to clean up. */
4168 {
4169 /* Do non-default initialization of trivial arrays resulting from
4170 brace-enclosed initializers. In this case, digest_init and
4171 store_constructor will handle the semantics for us. */
4177 }
4183 {
4189 }
4190 else
4193 /* The code we are generating looks like:
4194 ({
4195 T* t1 = (T*) base;
4196 T* rval = t1;
4197 ptrdiff_t iterator = maxindex;
4198 try {
4199 for (; iterator != -1; --iterator) {
4200 ... initialize *t1 ...
4201 ++t1;
4202 }
4203 } catch (...) {
4204 ... destroy elements that were constructed ...
4205 }
4206 rval;
4207 })
4209 We can omit the try and catch blocks if we know that the
4210 initialization will never throw an exception, or if the array
4211 elements do not have destructors. We can omit the loop completely if
4212 the elements of the array do not have constructors.
4214 We actually wrap the entire body of the above in a STMT_EXPR, for
4215 tidiness.
4217 When copying from array to another, when the array elements have
4218 only trivial copy constructors, we should use __builtin_memcpy
4219 rather than generating a loop. That way, we could take advantage
4220 of whatever cleverness the back end has for dealing with copies
4221 of blocks of memory. */
4230 /* If initializing one array from another, initialize element by
4231 element. We rely upon the below calls to do the argument
4232 checking. Evaluate the initializer before entering the try block. */
4234 {
4243 }
4245 /* Protect the entire array initialization so that we can destroy
4246 the partially constructed array if an exception is thrown.
4247 But don't do this if we're assigning. */
4250 {
4252 }
4254 /* Should we try to create a constant initializer? */
4258 : (type_has_constexpr_default_constructor
4264 /* If we're initializing a static array, we want to do static
4265 initialization of any elements with constant initializers even if
4266 some are non-constant. */
4272 /* Skip over the handling of non-empty init lists. */
4275 /* Maybe pull out constant value when from_array? */
4278 {
4279 /* Do non-default initialization of non-trivial arrays resulting from
4280 brace-enclosed initializers. */
4283 /* If the constructor already has the array type, it's been through
4284 digest_init, so we shouldn't try to do anything more. */
4295 {
4297 tree one_init;
4299 num_initialized_elts++;
4306 else
4312 {
4315 {
4319 else
4321 }
4322 else
4323 {
4325 {
4330 }
4332 }
4333 }
4340 complain);
4343 else
4347 complain);
4350 else
4352 }
4354 /* Any elements without explicit initializers get T{}. */
4356 }
4358 {
4359 /* Check that the array is at least as long as the string. */
4366 /* Copy the string to the first part of the array. */
4372 /* Adjust the counter and pointer. */
4381 /* And set the rest of the array to NUL. */
4384 }
4386 {
4391 {
4395 }
4396 }
4398 /* Now, default-initialize any remaining elements. We don't need to
4399 do that if a) the type does not need constructing, or b) we've
4400 already initialized all the elements.
4402 We do need to keep going if we're copying an array. */
4405 /* With a constexpr default constructor, which we checked for when
4406 setting try_const above, default-initialization is equivalent to
4407 value-initialization, and build_value_init gives us something more
4408 friendly to maybe_constant_init. */
4413 && (num_initialized_elts
4415 {
4416 /* If the ITERATOR is lesser or equal to -1, then we don't have to loop;
4417 we've already initialized all the elements. */
4418 tree for_stmt;
4419 tree elt_init;
4420 tree to;
4428 complain);
4435 /* If the initializer is {}, then all elements are initialized from T{}.
4436 But for non-classes, that's the same as value-initialization. */
4438 {
4440 {
4442 }
4443 else
4444 {
4447 }
4448 }
4451 {
4452 tree from;
4455 {
4461 }
4462 else
4475 complain);
4476 else
4478 }
4480 {
4482 {
4487 }
4488 else
4491 explicit_value_init_p,
4493 }
4495 {
4499 }
4500 else
4501 {
4505 else
4506 {
4509 complain);
4511 ? error_mark_node
4513 }
4514 }
4520 {
4521 /* FIXME refs to earlier elts */
4524 {
4526 /* Don't fill the CONSTRUCTOR with zeros. */
4530 }
4531 else
4532 {
4536 else
4538 }
4541 {
4544 {
4547 }
4548 }
4549 }
4557 complain));
4560 complain));
4563 }
4565 /* Make sure to cleanup any partially constructed elements. */
4568 {
4569 tree e;
4572 complain);
4574 /* Flatten multi-dimensional array since build_vec_delete only
4575 expects one-dimensional array. */
4579 /* Avoid mixing signed and unsigned. */
4582 complain);
4591 }
4593 /* The value of the array initialization is the array itself, RVAL
4594 is a pointer to the first element. */
4605 {
4607 {
4610 }
4613 else
4615 }
4617 /* Now make the result have the correct type. */
4619 {
4624 }
4627 }
4629 /* Call the DTOR_KIND destructor for EXP. FLAGS are as for
4630 build_delete. */
4632 static tree
4634 tsubst_flags_t complain)
4635 {
4636 tree name;
4638 {
4653 }
4658 flags,
4659 complain);
4660 }
4662 /* Generate a call to a destructor. TYPE is the type to cast ADDR to.
4663 ADDR is an expression which yields the store to be destroyed.
4664 AUTO_DELETE is the name of the destructor to call, i.e., either
4665 sfk_complete_destructor, sfk_base_destructor, or
4666 sfk_deleting_destructor.
4668 FLAGS is the logical disjunction of zero or more LOOKUP_
4669 flags. See cp-tree.h for more info. */
4671 tree
4674 {
4675 tree expr;
4682 /* Can happen when CURRENT_EXCEPTION_OBJECT gets its type
4683 set to `error_mark_node' before it gets properly cleaned up. */
4691 {
4693 {
4697 }
4700 }
4706 {
4709 /* We don't want to warn about delete of void*, only other
4710 incomplete types. Deleting other incomplete types
4711 invokes undefined behavior, but it is not ill-formed, so
4712 compile to something that would even do The Right Thing
4713 (TM) should the type have a trivial dtor and no delete
4714 operator. */
4716 {
4719 {
4722 "possible problem detected in invocation of "
4724 {
4727 "neither the destructor nor the class-specific "
4728 "operator delete will be called, even if they are "
4730 }
4731 }
4735 {
4738 {
4741 "deleting object of abstract class type %qT"
4742 " which has non-virtual destructor"
4744 else
4746 "deleting object of polymorphic class type %qT"
4747 " which has non-virtual destructor"
4749 }
4750 }
4751 }
4753 /* Throw away const and volatile on target type of addr. */
4755 }
4756 else
4757 {
4758 /* Don't check PROTECT here; leave that decision to the
4759 destructor. If the destructor is accessible, call it,
4760 else report error. */
4766 }
4769 /* We will use ADDR multiple times so we must save it. */
4774 {
4778 }
4784 {
4785 /* Leave do_delete null. */
4786 }
4787 /* For `::delete x', we must not use the deleting destructor
4788 since then we would not be sure to get the global `operator
4789 delete'. */
4791 {
4793 /* Delete the object. */
4795 head,
4800 complain);
4801 /* Otherwise, treat this like a complete object destructor
4802 call. */
4804 }
4805 /* If the destructor is non-virtual, there is no deleting
4806 variant. Instead, we must explicitly call the appropriate
4807 `operator delete' here. */
4809 {
4810 /* Build the call. */
4812 addr,
4817 complain);
4818 /* Call the complete object destructor. */
4820 }
4822 {
4823 /* Make sure we have access to the member op delete, even though
4824 we'll actually be calling it from the destructor. */
4829 complain);
4830 }
4835 else
4846 /* The delete operator must be called, regardless of whether
4847 the destructor throws.
4849 [expr.delete]/7 The deallocation function is called
4850 regardless of whether the destructor for the object or some
4851 element of the array throws an exception. */
4854 /* We need to calculate this before the dtor changes the vptr. */
4858 /* Handle deleting a null pointer. */
4866 /* This is a compiler generated comparison, don't emit
4867 e.g. -Wnonnull-compare warning for it. */
4875 }
4877 /* At the beginning of a destructor, push cleanups that will call the
4878 destructors for our base classes and members.
4880 Called from begin_destructor_body. */
4882 void
4884 {
4887 tree member;
4888 tree expr;
4891 /* Run destructors for all virtual baseclasses. */
4894 {
4895 tree cond = (condition_conversion
4897 current_in_charge_parm,
4898 integer_two_node)));
4900 /* The CLASSTYPE_VBASECLASSES vector is in initialization
4901 order, which is also the right order for pushing cleanups. */
4904 {
4906 {
4908 base_dtor_identifier,
4909 NULL,
4910 base_binfo,
4911 (LOOKUP_NORMAL
4913 tf_warning_or_error);
4915 {
4919 }
4920 }
4921 }
4922 }
4924 /* Take care of the remaining baseclasses. */
4927 {
4933 base_dtor_identifier,
4936 tf_warning_or_error);
4939 }
4941 /* Don't automatically destroy union members. */
4947 {
4956 {
4957 tree this_member = (build_class_member_access_expr
4961 tf_warning_or_error));
4963 sfk_complete_destructor,
4968 }
4969 }
4970 }
4972 /* Build a C++ vector delete expression.
4973 MAXINDEX is the number of elements to be deleted.
4974 ELT_SIZE is the nominal size of each element in the vector.
4975 BASE is the expression that should yield the store to be deleted.
4976 This function expands (or synthesizes) these calls itself.
4977 AUTO_DELETE_VEC says whether the container (vector) should be deallocated.
4979 This also calls delete for virtual baseclasses of elements of the vector.
4981 Update: MAXINDEX is no longer needed. The size can be extracted from the
4982 start of the vector for pointers, and from the type for arrays. We still
4983 use MAXINDEX for arrays because it happens to already have one of the
4984 values we'd have to extract. (We could use MAXINDEX with pointers to
4985 confirm the size, and trap if the numbers differ; not clear that it'd
4986 be worth bothering.) */
4988 tree
4990 special_function_kind auto_delete_vec,
4992 {
4993 tree type;
4994 tree rval;
5000 {
5001 /* Step back one from start of vector, and read dimension. */
5002 tree cookie_addr;
5007 {
5010 }
5015 cookie_addr);
5017 }
5019 {
5020 /* Get the total number of things in the array, maxindex is a
5021 bad name. */
5028 {
5031 }
5032 }
5033 else
5034 {
5038 }
5046 }