| blob | 52a927e46004c328a1752a83daeeb49e600b49df |
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 ;
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
287 {
290 }
292 /* In all cases, the initializer is a constant. */
297 }
299 /* Return an expression for the zero-initialization of an object with
300 type T. This expression will either be a constant (in the case
301 that T is a scalar), or a CONSTRUCTOR (in the case that T is an
302 aggregate), or NULL (in the case that T does not require
303 initialization). In either case, the value can be used as
304 DECL_INITIAL for a decl of the indicated TYPE; it is a valid static
305 initializer. If NELTS is non-NULL, and TYPE is an ARRAY_TYPE, NELTS
306 is the number of elements in the array. If STATIC_STORAGE_P is
307 TRUE, initializers are only generated for entities for which
308 zero-initialization does not simply mean filling the storage with
309 zero bytes. */
311 tree
313 {
315 }
317 /* Return a suitable initializer for value-initializing an object of type
318 TYPE, as described in [dcl.init]. */
320 tree
322 {
323 /* [dcl.init]
325 To value-initialize an object of type T means:
327 - if T is a class type (clause 9) with either no default constructor
328 (12.1) or a default constructor that is user-provided or deleted,
329 then the object is default-initialized;
331 - if T is a (possibly cv-qualified) class type without a user-provided
332 or deleted default constructor, then the object is zero-initialized
333 and the semantic constraints for default-initialization are checked,
334 and if T has a non-trivial default constructor, the object is
335 default-initialized;
337 - if T is an array type, then each element is value-initialized;
339 - otherwise, the object is zero-initialized.
341 A program that calls for default-initialization or
342 value-initialization of an entity of reference type is ill-formed. */
344 /* The AGGR_INIT_EXPR tweaking below breaks in templates. */
350 {
351 tree ctor =
354 complain);
364 {
365 /* This is a class that needs constructing, but doesn't have
366 a user-provided constructor. So we need to zero-initialize
367 the object and then call the implicitly defined ctor.
368 This will be handled in simplify_aggr_init_expr. */
371 }
372 }
374 /* Discard any access checking during subobject initialization;
375 the checks are implied by the call to the ctor which we have
376 verified is OK (cpp0x/defaulted46.C). */
381 }
383 /* Like build_value_init, but don't call the constructor for TYPE. Used
384 for base initializers. */
386 tree
388 {
390 {
394 }
395 /* FIXME the class and array cases should just use digest_init once it is
396 SFINAE-enabled. */
398 {
403 {
404 tree field;
407 /* Iterate over the fields, building initializations. */
409 {
420 /* We could skip vfields and fields of types with
421 user-defined constructors, but I think that won't improve
422 performance at all; it should be simpler in general just
423 to zero out the entire object than try to only zero the
424 bits that actually need it. */
426 /* Note that for class types there will be FIELD_DECLs
427 corresponding to base classes as well. Thus, iterating
428 over TYPE_FIELDs will result in correct initialization of
429 all of the subobjects. */
438 /* We shouldn't have gotten here for anything that would need
439 non-trivial initialization, and gimplify_init_ctor_preeval
440 would need to be fixed to allow it. */
443 }
445 /* Build a constructor to contain the zero- initializations. */
447 }
448 }
450 {
453 /* Iterate over the array elements, building initializations. */
456 /* If we have an error_mark here, we should just return error mark
457 as we don't know the size of the array yet. */
459 {
462 type);
464 }
467 /* A zero-sized array, which is accepted as an extension, will
468 have an upper bound of -1. */
470 {
471 constructor_elt ce;
473 /* If this is a one element array, we just use a regular init. */
476 else
487 /* We shouldn't have gotten here for anything that would need
488 non-trivial initialization, and gimplify_init_ctor_preeval
489 would need to be fixed to allow it. */
492 }
494 /* Build a constructor to contain the initializations. */
496 }
498 {
502 }
504 {
508 }
511 }
513 /* Initialize current class with INIT, a TREE_LIST of
514 arguments for a target constructor. If TREE_LIST is void_type_node,
515 an empty initializer list was given. */
517 static void
519 {
525 tf_warning_or_error));
527 {
529 LOOKUP_NORMAL
530 |LOOKUP_NONVIRTUAL
536 }
537 }
539 /* Return the non-static data initializer for FIELD_DECL MEMBER. */
543 tree
545 {
546 tree init;
551 {
553 location_t expr_loc
560 /* Check recursive instantiation. */
562 {
567 }
568 else
569 {
582 /* Do deferred instantiation of the NSDMI. */
583 init = (tsubst_copy_and_build
594 {
598 }
602 }
603 }
604 else
608 {
610 {
615 }
617 }
620 {
623 }
624 else
625 {
626 /* Use a PLACEHOLDER_EXPR when we don't have a 'this' parameter to
627 refer to; constexpr evaluation knows what to do with it. */
630 }
632 /* Strip redundant TARGET_EXPR so we don't need to remap it, and
633 so the aggregate init code below will see a CONSTRUCTOR. */
639 /* Now put it back so C++17 copy elision works. */
645 }
647 /* Diagnose the flexible array MEMBER if its INITializer is non-null
648 and return true if so. Otherwise return false. */
650 bool
652 {
660 /* Point at the flexible array member declaration if it's initialized
661 in-class, and at the ctor if it's initialized in a ctor member
662 initializer list. */
663 location_t loc;
665 || !current_function_decl
668 else
673 }
675 /* Initialize MEMBER, a FIELD_DECL, with INIT, a TREE_LIST of
676 arguments. If TREE_LIST is void_type_node, an empty initializer
677 list was given; if NULL_TREE no initializer was given. */
679 static void
681 {
682 tree decl;
685 /* Use the non-static data member initializer if there was no
686 mem-initializer for this field. */
693 /* Effective C++ rule 12 requires that all data members be
694 initialized. */
698 member);
700 /* Get an lvalue for the data member. */
704 tf_warning_or_error);
710 {
712 /* Handle references. */
719 member);
720 }
723 {
724 /* mem() means value-initialization. */
726 {
730 }
731 else
732 {
738 }
739 }
740 /* Deal with this here, as we will get confused if we try to call the
741 assignment op for an anonymous union. This can happen in a
742 synthesized copy constructor. */
744 {
746 {
749 }
750 }
753 /* Pre-digested NSDMI. */
756 /* { } mem-initializer. */
761 {
762 /* With references and list-initialization, we need to deal with
763 extending temporary lifetimes. 12.2p5: "A temporary bound to a
764 reference member in a constructor’s ctor-initializer (12.6.2)
765 persists until the constructor exits." */
770 tf_warning_or_error);
772 {
777 }
780 /* A FIELD_DECL doesn't really have a suitable lifetime, but
781 make_temporary_var_for_ref_to_temp will treat it as automatic and
782 set_up_extended_ref_temp wants to use the decl in a warning. */
792 }
795 {
797 {
799 {
800 /* Check to make sure the member initializer is valid and
801 something like a CONSTRUCTOR in: T a[] = { 1, 2 } and
802 if it isn't, return early to avoid triggering another
803 error below. */
809 else
814 }
818 {
820 {
821 /* Initialize the array only if it's not a flexible
822 array member (i.e., if it has an upper bound). */
826 }
827 }
828 else
830 }
831 else
832 {
839 {
840 /* TYPE_NEEDS_CONSTRUCTING can be set just because we have a
841 vtable; still give this diagnostic. */
846 }
848 tf_warning_or_error));
849 }
850 }
851 else
852 {
854 {
855 tree core_type;
856 /* member traversal: note it leaves init NULL */
858 {
863 }
865 {
870 }
880 }
882 /* There was an explicit member initialization. Do some work
883 in that case. */
885 tf_warning_or_error);
887 /* Reject a member initializer for a flexible array member. */
891 tf_warning_or_error));
892 }
895 {
896 tree expr;
901 tf_warning_or_error);
904 tf_warning_or_error);
909 }
910 }
912 /* Returns a TREE_LIST containing (as the TREE_PURPOSE of each node) all
913 the FIELD_DECLs on the TYPE_FIELDS list for T, in reverse order. */
915 static tree
917 {
918 tree fields;
920 /* Note whether or not T is a union. */
925 {
926 tree fieldtype;
928 /* Skip CONST_DECLs for enumeration constants and so forth. */
934 /* For an anonymous struct or union, we must recursively
935 consider the fields of the anonymous type. They can be
936 directly initialized from the constructor. */
938 {
939 /* Add this field itself. Synthesized copy constructors
940 initialize the entire aggregate. */
942 /* And now add the fields in the anonymous aggregate. */
945 }
946 /* Add this field. */
949 }
952 }
954 /* Return the innermost aggregate scope for FIELD, whether that is
955 the enclosing class or an anonymous aggregate within it. */
957 static tree
959 {
962 else
964 }
966 /* The MEM_INITS are a TREE_LIST. The TREE_PURPOSE of each list gives
967 a FIELD_DECL or BINFO in T that needs initialization. The
968 TREE_VALUE gives the initializer, or list of initializer arguments.
970 Return a TREE_LIST containing all of the initializations required
971 for T, in the order in which they should be performed. The output
972 list has the same format as the input. */
974 static tree
976 {
977 tree init;
979 tree sorted_inits;
980 tree next_subobject;
985 /* Build up a list of initializations. The TREE_PURPOSE of entry
986 will be the subobject (a FIELD_DECL or BINFO) to initialize. The
987 TREE_VALUE will be the constructor arguments, or NULL if no
988 explicit initialization was provided. */
991 /* Process the virtual bases. */
996 /* Process the direct bases. */
1002 /* Process the non-static data members. */
1004 /* Reverse the entire list of initializations, so that they are in
1005 the order that they will actually be performed. */
1008 /* If the user presented the initializers in an order different from
1009 that in which they will actually occur, we issue a warning. Keep
1010 track of the next subobject which can be explicitly initialized
1011 without issuing a warning. */
1014 /* Go through the explicit initializers, filling in TREE_PURPOSE in
1015 the SORTED_INITS. */
1017 {
1018 tree subobject;
1019 tree subobject_init;
1023 /* If the explicit initializers are in sorted order, then
1024 SUBOBJECT will be NEXT_SUBOBJECT, or something following
1025 it. */
1027 subobject_init;
1032 /* Issue a warning if the explicit initializer order does not
1033 match that which will actually occur.
1034 ??? Are all these on the correct lines? */
1036 {
1041 else
1047 else
1051 }
1053 /* Look again, from the beginning of the list. */
1055 {
1059 }
1061 /* It is invalid to initialize the same subobject more than
1062 once. */
1064 {
1068 subobject);
1069 else
1072 subobject);
1073 }
1075 /* Record the initialization. */
1078 }
1080 /* [class.base.init]
1082 If a ctor-initializer specifies more than one mem-initializer for
1083 multiple members of the same union (including members of
1084 anonymous unions), the ctor-initializer is ill-formed.
1086 Here we also splice out uninitialized union members. */
1088 {
1092 {
1093 tree field;
1094 tree ctx;
1100 /* Skip base classes. */
1104 /* If this is an anonymous aggregate with no explicit initializer,
1105 splice it out. */
1109 /* See if this field is a member of a union, or a member of a
1110 structure contained in a union, etc. */
1113 /* If this field is not a member of a union, skip it. */
1118 /* If this union member has no explicit initializer and no NSDMI,
1119 splice it out. */
1122 else
1125 /* It's only an error if we have two initializers for the same
1126 union type. */
1128 {
1131 }
1133 /* See if LAST_FIELD and the field initialized by INIT are
1134 members of the same union (or the union itself). If so, there's
1135 a problem, unless they're actually members of the same structure
1136 which is itself a member of a union. For example, given:
1138 union { struct { int i; int j; }; };
1140 initializing both `i' and `j' makes sense. */
1141 ctx = common_enclosing_class
1147 {
1148 /* A mem-initializer hides an NSDMI. */
1153 else
1154 {
1157 ctx);
1159 }
1160 }
1164 next:
1167 splice:
1170 }
1171 }
1174 }
1176 /* Callback for cp_walk_tree to mark all PARM_DECLs in a tree as read. */
1178 static tree
1180 {
1185 }
1187 /* Initialize all bases and members of CURRENT_CLASS_TYPE. MEM_INITS
1188 is a TREE_LIST giving the explicit mem-initializer-list for the
1189 constructor. The TREE_PURPOSE of each entry is a subobject (a
1190 FIELD_DECL or a BINFO) of the CURRENT_CLASS_TYPE. The TREE_VALUE
1191 is a TREE_LIST giving the arguments to the constructor or
1192 void_type_node for an empty list of arguments. */
1194 void
1196 {
1199 /* We will already have issued an error message about the fact that
1200 the type is incomplete. */
1207 {
1208 /* Delegating constructor. */
1212 }
1218 /* Sort the mem-initializers into the order in which the
1219 initializations should be performed. */
1224 /* Initialize base classes. */
1228 {
1232 /* We already have issued an error message. */
1236 /* Suppress access control when calling the inherited ctor. */
1238 && flag_new_inheriting_ctors
1244 {
1245 /* If these initializations are taking place in a copy constructor,
1246 the base class should probably be explicitly initialized if there
1247 is a user-defined constructor in the base class (other than the
1248 default constructor, which will be called anyway). */
1256 }
1258 /* Initialize the base. */
1260 {
1261 tree base_addr;
1267 arguments,
1268 flags,
1269 tf_warning_or_error);
1271 }
1273 /* C++14 DR1658 Means we do not have to construct vbases of
1274 abstract classes. */
1276 else
1277 /* When not constructing vbases of abstract classes, at least mark
1278 the arguments expressions as read to avoid
1279 -Wunused-but-set-parameter false positives. */
1284 }
1287 /* Initialize the vptrs. */
1290 /* Initialize the data members. */
1292 {
1296 }
1297 }
1299 /* Returns the address of the vtable (i.e., the value that should be
1300 assigned to the vptr) for BINFO. */
1302 tree
1304 {
1306 tree vtbl;
1309 /* If this is a virtual primary base, then the vtable we want to store
1310 is that for the base this is being used as the primary base of. We
1311 can't simply skip the initialization, because we may be expanding the
1312 inits of a subobject constructor where the virtual base layout
1313 can be different. */
1317 /* Figure out what vtable BINFO's vtable is based on, and mark it as
1318 used. */
1322 /* Now compute the address to use when initializing the vptr. */
1328 }
1330 /* This code sets up the virtual function tables appropriate for
1331 the pointer DECL. It is a one-ply initialization.
1333 BINFO is the exact type that DECL is supposed to be. In
1334 multiple inheritance, this might mean "C's A" if C : A, B. */
1336 static void
1338 {
1340 tree vtt_index;
1342 /* Compute the initializer for vptr. */
1345 /* We may get this vptr from a VTT, if this is a subobject
1346 constructor or subobject destructor. */
1349 {
1350 tree vtbl2;
1351 tree vtt_parm;
1353 /* Compute the value to use, when there's a VTT. */
1359 /* The actual initializer is the VTT value only in the subobject
1360 constructor. In maybe_clone_body we'll substitute NULL for
1361 the vtt_parm in the case of the non-subobject constructor. */
1363 }
1365 /* Compute the location of the vtpr. */
1370 /* Assign the vtable to the vptr. */
1374 }
1376 /* If an exception is thrown in a constructor, those base classes already
1377 constructed must be destroyed. This function creates the cleanup
1378 for BINFO, which has just been constructed. If FLAG is non-NULL,
1379 it is a DECL which is nonzero when this base needs to be
1380 destroyed. */
1382 static void
1384 {
1385 tree expr;
1390 /* Call the destructor. */
1392 base_dtor_identifier,
1393 NULL,
1394 binfo,
1396 tf_warning_or_error);
1408 }
1410 /* Construct the virtual base-class VBASE passing the ARGUMENTS to its
1411 constructor. */
1413 static void
1415 {
1416 tree inner_if_stmt;
1417 tree exp;
1418 tree flag;
1420 /* If there are virtual base classes with destructors, we need to
1421 emit cleanups to destroy them if an exception is thrown during
1422 the construction process. These exception regions (i.e., the
1423 period during which the cleanups must occur) begin from the time
1424 the construction is complete to the end of the function. If we
1425 create a conditional block in which to initialize the
1426 base-classes, then the cleanup region for the virtual base begins
1427 inside a block, and ends outside of that block. This situation
1428 confuses the sjlj exception-handling code. Therefore, we do not
1429 create a single conditional block, but one for each
1430 initialization. (That way the cleanup regions always begin
1431 in the outer block.) We trust the back end to figure out
1432 that the FLAG will not change across initializations, and
1433 avoid doing multiple tests. */
1438 /* Compute the location of the virtual base. If we're
1439 constructing virtual bases, then we must be the most derived
1440 class. Therefore, we don't have to look up the virtual base;
1441 we already know where it is. */
1450 }
1452 /* Find the context in which this FIELD can be initialized. */
1454 static tree
1456 {
1459 /* Anonymous union members can be initialized in the first enclosing
1460 non-anonymous union context. */
1464 }
1466 /* Function to give error message if member initialization specification
1467 is erroneous. FIELD is the member we decided to initialize.
1468 TYPE is the type for which the initialization is being performed.
1469 FIELD must be a member of TYPE.
1471 MEMBER_NAME is the name of the member. */
1473 static int
1475 {
1479 {
1481 member_name);
1483 }
1485 {
1488 field);
1490 }
1492 {
1496 }
1498 {
1500 member_name);
1502 }
1505 }
1507 /* NAME is a FIELD_DECL, an IDENTIFIER_NODE which names a field, or it
1508 is a _TYPE node or TYPE_DECL which names a base for that type.
1509 Check the validity of NAME, and return either the base _TYPE, base
1510 binfo, or the FIELD_DECL of the member. If NAME is invalid, return
1511 NULL_TREE and issue a diagnostic.
1513 An old style unnamed direct single base construction is permitted,
1514 where NAME is NULL. */
1516 tree
1518 {
1519 tree basetype;
1520 tree field;
1526 {
1527 /* This is an obsolete unnamed base class initializer. The
1528 parser will already have warned about its use. */
1530 {
1533 current_class_type);
1536 basetype = BINFO_TYPE
1541 current_class_type);
1543 }
1544 }
1546 {
1549 }
1552 else
1556 {
1557 tree class_binfo;
1558 tree direct_binfo;
1559 tree virtual_binfo;
1570 /* Look for a direct base. */
1575 /* Look for a virtual base -- unless the direct base is itself
1576 virtual. */
1580 /* [class.base.init]
1582 If a mem-initializer-id is ambiguous because it designates
1583 both a direct non-virtual base class and an inherited virtual
1584 base class, the mem-initializer is ill-formed. */
1586 {
1588 basetype);
1590 }
1593 {
1597 else
1601 }
1604 }
1605 else
1606 {
1609 else
1614 }
1617 }
1619 /* This is like `expand_member_init', only it stores one aggregate
1620 value into another.
1622 INIT comes in two flavors: it is either a value which
1623 is to be stored in EXP, or it is a parameter list
1624 to go to a constructor, which will operate on EXP.
1625 If INIT is not a parameter list for a constructor, then set
1626 LOOKUP_ONLYCONVERTING.
1627 If FLAGS is LOOKUP_ONLYCONVERTING then it is the = init form of
1628 the initializer, if FLAGS is 0, then it is the (init) form.
1629 If `init' is a CONSTRUCTOR, then we emit a warning message,
1630 explaining that such initializations are invalid.
1632 If INIT resolves to a CALL_EXPR which happens to return
1633 something of the type we are looking for, then we know
1634 that we can safely use that call to perform the
1635 initialization.
1637 The virtual function table pointer cannot be set up here, because
1638 we do not really know its type.
1640 This never calls operator=().
1642 When initializing, nothing is CONST.
1644 A default copy constructor may have to be used to perform the
1645 initialization.
1647 A constructor or a conversion operator may have to be used to
1648 perform the initialization, but not both, as it would be ambiguous. */
1650 tree
1652 {
1653 tree stmt_expr;
1654 tree compound_stmt;
1664 location_t init_loc = (init
1672 {
1677 {
1681 {
1682 /* Wrap the initializer in a CONSTRUCTOR so that build_vec_init
1683 recognizes it as direct-initialization. */
1687 }
1688 }
1689 else
1690 {
1691 /* Must arrange to initialize each element of EXP
1692 from elements of INIT. */
1701 && (!from_array
1703 /* Can happen, eg, handling the compound-literals
1704 extension (ext/complit12.C). */
1706 {
1711 }
1712 }
1716 from_array,
1717 complain);
1721 /* Restore the type of init unless it was used directly. */
1725 }
1736 /* Just know that we've seen something for this node. */
1750 }
1752 static void
1754 tsubst_flags_t complain)
1755 {
1758 /* It fails because there may not be a constructor which takes
1759 its own type as the first (or only parameter), but which does
1760 take other types via a conversion. So, if the thing initializing
1761 the expression is a unit element of type X, first try X(X&),
1762 followed by initialization by X. If neither of these work
1763 out, then look hard. */
1764 tree rval;
1767 /* If we have direct-initialization from an initializer list, pull
1768 it out of the TREE_LIST so the code below can see it. */
1771 {
1775 /* Only call reshape_init if it has not been called earlier
1776 by the callers. */
1779 }
1783 /* A brace-enclosed initializer for an aggregate. In C++0x this can
1784 happen for direct-initialization, too. */
1787 /* A CONSTRUCTOR of the target's type is a previously digested
1788 initializer, whether that happened just above or in
1789 cp_parser_late_parsing_nsdmi.
1791 A TARGET_EXPR with TARGET_EXPR_DIRECT_INIT_P or TARGET_EXPR_LIST_INIT_P
1792 set represents the whole initialization, so we shouldn't build up
1793 another ctor call. */
1800 {
1801 /* Early initialization via a TARGET_EXPR only works for
1802 complete objects. */
1809 }
1813 {
1814 /* Base subobjects should only get direct-initialization. */
1818 /* Do nothing. We hit this in two cases: Reference initialization,
1819 where we aren't initializing a real variable, so we don't want
1820 to run a new constructor; and catching an exception, where we
1821 have already built up the constructor call so we could wrap it
1823 else
1828 /* We need to protect the initialization of a catch parm with a
1829 call to terminate(), which shows up as a MUST_NOT_THROW_EXPR
1830 around the TARGET_EXPR for the copy constructor. See
1831 initialize_handler_parm. */
1832 {
1836 }
1837 else
1842 }
1847 {
1851 }
1852 else
1857 {
1858 /* Delegating constructor. */
1859 tree complete;
1860 tree base;
1863 /* Unshare the arguments for the second call. */
1866 {
1869 }
1872 complain);
1878 complain);
1881 }
1882 else
1883 {
1888 complain);
1889 }
1895 {
1898 {
1902 }
1903 }
1905 /* FIXME put back convert_to_void? */
1908 }
1910 /* This function is responsible for initializing EXP with INIT
1911 (if any).
1913 BINFO is the binfo of the type for who we are performing the
1914 initialization. For example, if W is a virtual base class of A and B,
1915 and C : A, B.
1916 If we are initializing B, then W must contain B's W vtable, whereas
1917 were we initializing C, W must contain C's W vtable.
1919 TRUE_EXP is nonzero if it is the true expression being initialized.
1920 In this case, it may be EXP, or may just contain EXP. The reason we
1921 need this is because if EXP is a base element of TRUE_EXP, we
1922 don't necessarily know by looking at EXP where its virtual
1923 baseclass fields should really be pointing. But we do know
1924 from TRUE_EXP. In constructors, we don't know anything about
1925 the value being initialized.
1927 FLAGS is just passed to `build_new_method_call'. See that function
1928 for its description. */
1930 static void
1932 tsubst_flags_t complain)
1933 {
1939 /* Use a function returning the desired type to initialize EXP for us.
1940 If the function is a constructor, and its first argument is
1941 NULL_TREE, know that it was meant for us--just slide exp on
1942 in and expand the constructor. Constructors now come
1943 as TARGET_EXPRs. */
1947 {
1949 /* If store_init_value returns NULL_TREE, the INIT has been
1950 recorded as the DECL_INITIAL for EXP. That means there's
1951 nothing more we have to do. */
1957 }
1959 /* List-initialization from {} becomes value-initialization for non-aggregate
1960 classes with default constructors. Handle this here when we're
1961 initializing a base, so protected access works. */
1963 {
1970 }
1972 /* If an explicit -- but empty -- initializer list was present,
1973 that's value-initialization. */
1975 {
1976 /* If the type has data but no user-provided ctor, we need to zero
1977 out the object. */
1980 {
1983 /* Don't clobber already initialized virtual bases. */
1986 field_size);
1989 }
1991 /* If we don't need to mess with the constructor at all,
1992 then we're done. */
1996 /* Otherwise fall through and call the constructor. */
1998 }
2000 /* We know that expand_default_init can handle everything we want
2001 at this point. */
2003 }
2005 /* Report an error if TYPE is not a user-defined, class type. If
2006 OR_ELSE is nonzero, give an error message. */
2008 int
2010 {
2015 {
2019 }
2021 }
2023 tree
2025 {
2031 else
2033 }
2035 /* Build a reference to a member of an aggregate. This is not a C++
2036 `&', but really something which can have its address taken, and
2037 then act as a pointer to member, for example TYPE :: FIELD can have
2038 its address taken by saying & TYPE :: FIELD. ADDRESS_P is true if
2039 this expression is the operand of "&".
2041 @@ Prints out lousy diagnostics for operator <typename>
2042 @@ fields.
2044 @@ This function should be rewritten and placed in search.c. */
2046 tree
2048 tsubst_flags_t complain)
2049 {
2050 tree decl;
2053 /* class templates can come in as TEMPLATE_DECLs here. */
2066 /* Callers should call mark_used before this point. */
2071 {
2075 }
2077 /* Entities other than non-static members need no further
2078 processing. */
2085 {
2089 }
2091 /* Set up BASEBINFO for member lookup. */
2094 /* A lot of this logic is now handled in lookup_member. */
2096 {
2097 /* Go from the TREE_BASELINK to the member function info. */
2101 {
2102 /* Get rid of a potential OVERLOAD around it. */
2105 /* Unique functions are handled easily. */
2107 /* For non-static member of base class, we need a special rule
2108 for access checking [class.protected]:
2110 If the access is to form a pointer to member, the
2111 nested-name-specifier shall name the derived class
2112 (or any class derived from that class). */
2117 complain);
2118 else
2120 complain);
2126 }
2127 else
2129 }
2131 {
2132 /* We need additional test besides the one in
2133 check_accessibility_of_qualified_id in case it is
2134 a pointer to non-static member. */
2136 complain))
2138 }
2141 {
2142 /* If MEMBER is non-static, then the program has fallen afoul of
2143 [expr.prim]:
2145 An id-expression that denotes a nonstatic data member or
2146 nonstatic member function of a class can only be used:
2148 -- as part of a class member access (_expr.ref_) in which the
2149 object-expression refers to the member's class or a class
2150 derived from that class, or
2152 -- to form a pointer to member (_expr.unary.op_), or
2154 -- in the body of a nonstatic member function of that class or
2155 of a class derived from that class (_class.mfct.nonstatic_), or
2157 -- in a mem-initializer for a constructor for that class or for
2158 a class derived from that class (_class.base.init_). */
2160 {
2161 /* Build a representation of the qualified name suitable
2162 for use as the operand to "&" -- even though the "&" is
2163 not actually present. */
2165 /* In Microsoft mode, treat a non-static member function as if
2166 it were a pointer-to-member. */
2168 {
2171 }
2176 }
2178 {
2182 }
2184 }
2189 }
2191 /* If DECL is a scalar enumeration constant or variable with a
2192 constant initializer, return the initializer (or, its initializers,
2193 recursively); otherwise, return DECL. If STRICT_P, the
2194 initializer is only returned if DECL is a
2195 constant-expression. If RETURN_AGGREGATE_CST_OK_P, it is ok to
2196 return an aggregate constant. */
2198 static tree
2200 {
2205 {
2206 tree init;
2207 /* If DECL is a static data member in a template
2208 specialization, we must instantiate it here. The
2209 initializer for the static data member is not processed
2210 until needed; we need it now. */
2214 {
2217 /* Treat the error as a constant to avoid cascading errors on
2218 excessively recursive template instantiation (c++/9335). */
2220 else
2222 }
2223 /* Initializers in templates are generally expanded during
2224 instantiation, so before that for const int i(2)
2225 INIT is a TREE_LIST with the actual initializer as
2226 TREE_VALUE. */
2228 && init
2232 /* Instantiate a non-dependent initializer for user variables. We
2233 mustn't do this for the temporary for an array compound literal;
2234 trying to instatiate the initializer will keep creating new
2235 temporaries until we crash. Probably it's not useful to do it for
2236 other artificial variables, either. */
2242 || (!return_aggregate_cst_ok_p
2243 /* Unless RETURN_AGGREGATE_CST_OK_P is true, do not
2244 return an aggregate constant (of which string
2245 literals are a special case), as we do not want
2246 to make inadvertent copies of such entities, and
2247 we must be sure that their addresses are the
2248 same everywhere. */
2252 /* Don't return a CONSTRUCTOR for a variable with partial run-time
2253 initialization, since it doesn't represent the entire value. */
2257 /* If the variable has a dynamic initializer, don't use its
2258 DECL_INITIAL which doesn't reflect the real value. */
2265 }
2267 }
2269 /* If DECL is a CONST_DECL, or a constant VAR_DECL initialized by constant
2270 of integral or enumeration type, or a constexpr variable of scalar type,
2271 then return that value. These are those variables permitted in constant
2272 expressions by [5.19/1]. */
2274 tree
2276 {
2279 }
2281 /* Like scalar_constant_value, but can also return aggregate initializers. */
2283 tree
2285 {
2288 }
2290 /* A more relaxed version of scalar_constant_value, used by the
2291 common C/C++ code. */
2293 tree
2295 {
2298 }
2299 \f
2300 /* Common subroutines of build_new and build_vec_delete. */
2301 \f
2302 /* Build and return a NEW_EXPR. If NELTS is non-NULL, TYPE[NELTS] is
2303 the type of the object being allocated; otherwise, it's just TYPE.
2304 INIT is the initializer, if any. USE_GLOBAL_NEW is true if the
2305 user explicitly wrote "::operator new". PLACEMENT, if non-NULL, is
2306 a vector of arguments to be provided as arguments to a placement
2307 new operator. This routine performs no semantic checks; it just
2308 creates and returns a NEW_EXPR. */
2310 static tree
2313 {
2314 tree init_list;
2315 tree new_expr;
2317 /* If INIT is NULL, the we want to store NULL_TREE in the NEW_EXPR.
2318 If INIT is not NULL, then we want to store VOID_ZERO_NODE. This
2319 permits us to distinguish the case of a missing initializer "new
2320 int" from an empty initializer "new int()". */
2325 else
2326 {
2331 }
2335 init_list);
2340 }
2342 /* Diagnose uninitialized const members or reference members of type
2343 TYPE. USING_NEW is used to disambiguate the diagnostic between a
2344 new expression without a new-initializer and a declaration. Returns
2345 the error count. */
2347 static int
2350 {
2351 tree field;
2358 {
2359 tree field_type;
2370 {
2373 {
2375 {
2379 else
2381 }
2382 else
2383 {
2388 else
2391 }
2394 }
2395 }
2398 {
2401 {
2403 {
2407 else
2409 }
2410 else
2411 {
2416 else
2419 }
2422 }
2423 }
2426 error_count
2429 }
2431 }
2433 int
2435 {
2437 }
2439 /* Call __cxa_bad_array_new_length to indicate that the size calculation
2440 overflowed. Pretend it returns sizetype so that it plays nicely in the
2441 COND_EXPR. */
2443 tree
2445 {
2447 {
2452 fn = push_throw_library_fn
2454 }
2457 }
2459 /* Attempt to find the initializer for flexible array field T in the
2460 initializer INIT, when non-null. Returns the initializer when
2461 successful and NULL otherwise. */
2462 static tree
2464 {
2471 /* Iterate over all top-level initializer elements. */
2473 /* If the member T is found, return it. */
2478 }
2480 /* Attempt to verify that the argument, OPER, of a placement new expression
2481 refers to an object sufficiently large for an object of TYPE or an array
2482 of NELTS of such objects when NELTS is non-null, and issue a warning when
2483 it does not. SIZE specifies the size needed to construct the object or
2484 array and captures the result of NELTS * sizeof (TYPE). (SIZE could be
2485 greater when the array under construction requires a cookie to store
2486 NELTS. GCC's placement new expression stores the cookie when invoking
2487 a user-defined placement new operator function but not the default one.
2488 Placement new expressions with user-defined placement new operator are
2489 not diagnosed since we don't know how they use the buffer (this could
2490 be a future extension). */
2491 static void
2493 {
2496 /* The number of bytes to add to or subtract from the size of the provided
2497 buffer based on an offset into an array or an array element reference.
2498 Although intermediate results may be negative (as in a[3] - 2) a valid
2499 final result cannot be. */
2501 /* True when the size of the entire destination object should be used
2502 to compute the possibly optimistic estimate of the available space. */
2504 /* True when the reference to the destination buffer is an ADDR_EXPR. */
2509 /* Using a function argument or a (non-array) variable as an argument
2510 to placement new is not checked since it's unknown what it might
2511 point to. */
2517 /* Evaluate any constant expressions. */
2520 /* Handle the common case of array + offset expression when the offset
2521 is a constant. */
2523 {
2524 /* If the offset is compile-time constant, use it to compute a more
2525 accurate estimate of the size of the buffer. Since the operand
2526 of POINTER_PLUS_EXPR is represented as an unsigned type, convert
2527 it to signed first.
2528 Otherwise, use the size of the entire array as an optimistic
2529 estimate (this may lead to false negatives). */
2533 else
2539 }
2544 {
2547 }
2553 {
2554 /* Similar to the offset computed above, see if the array index
2555 is a compile-time constant. If so, and unless the offset was
2556 not a compile-time constant, use the index to determine the
2557 size of the buffer. Otherwise, use the entire array as
2558 an optimistic estimate of the size. */
2562 else
2563 {
2566 }
2569 }
2571 /* Refers to the declared object that constains the subobject referenced
2572 by OPER. When the object is initialized, makes it possible to determine
2573 the actual size of a flexible array member used as the buffer passed
2574 as OPER to placement new. */
2576 /* True when operand is a COMPONENT_REF, to distinguish flexible array
2577 members from arrays of unspecified size. */
2580 /* For COMPONENT_REF (i.e., a struct member) the size of the entire
2581 enclosing struct. Used to validate the adjustment (offset) into
2582 an array at the end of a struct. */
2585 /* Descend into a struct or union to find the member whose address
2586 is being used as the argument. */
2588 {
2597 }
2604 {
2605 /* A possibly optimistic estimate of the number of bytes available
2606 in the destination buffer. */
2608 /* True when the estimate above is in fact the exact size
2609 of the destination buffer rather than an estimate. */
2612 /* Treat members of unions and members of structs uniformly, even
2613 though the size of a member of a union may be viewed as extending
2614 to the end of the union itself (it is by __builtin_object_size). */
2618 {
2619 /* Use the size of the entire array object when the expression
2620 refers to a variable or its size depends on an expression
2621 that's not a compile-time constant. */
2624 }
2626 {
2627 /* Use the size of the type of the destination buffer object
2628 as the optimistic estimate of the available space in it.
2629 Use the maximum possible size for zero-size arrays and
2630 flexible array members (except of initialized objects
2631 thereof). */
2634 }
2637 {
2639 {
2640 /* Constructing into a buffer provided by the flexible array
2641 member of a declared object (which is permitted as a G++
2642 extension). If the array member has been initialized,
2643 determine its size from the initializer. Otherwise,
2644 the array size is zero. */
2648 }
2649 else
2652 }
2657 {
2662 && !var_decl
2665 }
2667 /* Reduce the size of the buffer by the adjustment computed above
2668 from the offset and/or the index into the array. */
2671 else
2672 {
2676 {
2680 }
2681 }
2683 /* The minimum amount of space needed for the allocation. This
2684 is an optimistic estimate that makes it possible to detect
2685 placement new invocation for some undersize buffers but not
2686 others. */
2687 offset_int bytes_need;
2696 else
2697 {
2698 /* The type is a VLA. */
2700 }
2703 {
2707 exact_size ?
2708 "placement new constructing an object of type "
2709 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2710 "and size %qwi"
2712 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2716 else
2718 exact_size ?
2719 "placement new constructing an array of objects "
2720 "of type %qT and size %qwu in a region of type %qT "
2721 "and size %qwi"
2723 "of type %qT and size %qwu in a region of type %qT "
2727 else
2729 exact_size ?
2730 "placement new constructing an object of type %qT "
2731 "and size %qwu in a region of type %qT and size %qwi"
2733 "and size %qwu in a region of type %qT and size "
2737 }
2738 }
2739 }
2741 /* True if alignof(T) > __STDCPP_DEFAULT_NEW_ALIGNMENT__. */
2743 bool
2745 {
2748 }
2750 /* Return the alignment we expect malloc to guarantee. This should just be
2751 MALLOC_ABI_ALIGNMENT, but that macro defaults to only BITS_PER_WORD for some
2752 reason, so don't let the threshold be smaller than max_align_t_align. */
2754 unsigned
2756 {
2758 }
2760 /* Determine whether an allocation function is a namespace-scope
2761 non-replaceable placement new function. See DR 1748.
2762 TODO: Enable in all standard modes. */
2763 static bool
2765 {
2767 {
2772 }
2774 }
2776 /* Generate code for a new-expression, including calling the "operator
2777 new" function, initializing the object, and, if an exception occurs
2778 during construction, cleaning up. The arguments are as for
2779 build_raw_new_expr. This may change PLACEMENT and INIT.
2780 TYPE is the type of the object being constructed, possibly an array
2781 of NELTS elements when NELTS is non-null (in "new T[NELTS]", T may
2782 be an array of the form U[inner], with the whole expression being
2783 "new U[NELTS][inner]"). */
2785 static tree
2788 tsubst_flags_t complain)
2789 {
2791 /* True iff this is a call to "operator new[]" instead of just
2792 "operator new". */
2794 /* If ARRAY_P is true, the element type of the array. This is never
2795 an ARRAY_TYPE; for something like "new int[3][4]", the
2796 ELT_TYPE is "int". If ARRAY_P is false, this is the same type as
2797 TYPE. */
2798 tree elt_type;
2799 /* The type of the new-expression. (This type is always a pointer
2800 type.) */
2801 tree pointer_type;
2802 tree non_const_pointer_type;
2803 /* The most significant array bound in int[OUTER_NELTS][inner]. */
2805 /* For arrays with a non-constant number of elements, a bounds checks
2806 on the NELTS parameter to avoid integer overflow at runtime. */
2809 /* Number of the "inner" elements in "new T[OUTER_NELTS][inner]". */
2812 /* Size of the inner array elements (those with constant dimensions). */
2813 offset_int inner_size;
2814 /* The address returned by the call to "operator new". This node is
2815 a VAR_DECL and is therefore reusable. */
2816 tree alloc_node;
2817 tree alloc_fn;
2820 /* If non-NULL, the number of extra bytes to allocate at the
2821 beginning of the storage allocated for an array-new expression in
2822 order to store the number of elements. */
2824 tree placement_first;
2826 /* True if the function we are calling is a placement allocation
2827 function. */
2829 /* True if the storage must be initialized, either by a constructor
2830 or due to an explicit new-initializer. */
2832 /* The address of the thing allocated, not including any cookie. In
2833 particular, if an array cookie is in use, DATA_ADDR is the
2834 address of the first array element. This node is a VAR_DECL, and
2835 is therefore reusable. */
2836 tree data_addr;
2841 {
2844 }
2846 {
2847 /* Transforms new (T[N]) to new T[N]. The former is a GNU
2848 extension for variable N. (This also covers new T where T is
2849 a VLA typedef.) */
2855 }
2857 /* Lots of logic below. depends on whether we have a constant number of
2858 elements, so go ahead and fold it now. */
2862 /* If our base type is an array, then make sure we know how many elements
2863 it has. */
2867 {
2871 {
2876 {
2880 }
2882 }
2883 else
2884 {
2886 {
2890 }
2892 }
2896 inner_nelts_cst,
2897 complain);
2898 }
2901 {
2904 }
2909 /* Warn if we performed the (T[N]) to T[N] transformation and N is
2910 variable. */
2913 {
2915 {
2922 }
2923 else
2925 }
2928 {
2932 }
2940 {
2942 /* A program that calls for default-initialization [...] of an
2943 entity of reference type is ill-formed. */
2947 /* A new-expression that creates an object of type T initializes
2948 that object as follows:
2949 - If the new-initializer is omitted:
2950 -- If T is a (possibly cv-qualified) non-POD class type
2951 (or array thereof), the object is default-initialized (8.5).
2952 [...]
2953 -- Otherwise, the object created has indeterminate
2954 value. If T is a const-qualified type, or a (possibly
2955 cv-qualified) POD class type (or array thereof)
2956 containing (directly or indirectly) a member of
2957 const-qualified type, the program is ill-formed; */
2967 }
2971 {
2975 }
2979 {
2980 /* Maximum available size in bytes. Half of the address space
2981 minus the cookie size. */
2982 offset_int max_size
2984 /* Maximum number of outer elements which can be allocated. */
2985 offset_int max_outer_nelts;
2986 tree max_outer_nelts_tree;
2992 /* Unconditionally subtract the cookie size. This decreases the
2993 maximum object size and is safe even if we choose not to use
2994 a cookie after all. */
3000 {
3004 }
3012 {
3014 {
3015 /* When the array size is constant, check it at compile time
3016 to make sure it doesn't exceed the implementation-defined
3017 maximum, as required by C++ 14 (in C++ 11 this requirement
3018 isn't explicitly stated but it's enforced anyway -- see
3019 grokdeclarator in cp/decl.c). */
3023 }
3024 }
3025 else
3026 {
3027 /* When a runtime check is necessary because the array size
3028 isn't constant, keep only the top-most seven bits (starting
3029 with the most significant non-zero bit) of the maximum size
3030 to compare the array size against, to simplify encoding the
3031 constant maximum size in the instruction stream. */
3038 outer_nelts,
3039 max_outer_nelts_tree);
3040 }
3041 }
3049 /* If PLACEMENT is a single simple pointer type not passed by
3050 reference, prepare to capture it in a temporary variable. Do
3051 this now, since PLACEMENT will change in the calls below. */
3059 /* Allocate the object. */
3060 tree fnname;
3061 tree fns;
3065 member_new_p = !globally_qualified_p
3067 && (array_p
3072 {
3073 /* Use a class-specific operator new. */
3074 /* If a cookie is required, add some extra space. */
3077 else
3078 {
3080 /* No size arithmetic necessary, so the size check is
3081 not needed. */
3084 }
3085 /* Perform the overflow check. */
3092 /* Create the argument list. */
3094 /* Do name-lookup to find the appropriate operator. */
3097 {
3101 }
3103 {
3105 {
3108 }
3110 }
3114 {
3117 alloc_call
3121 /* If no matching function is found and the allocated object type
3122 has new-extended alignment, the alignment argument is removed
3123 from the argument list, and overload resolution is performed
3124 again. */
3127 }
3131 LOOKUP_NORMAL,
3133 }
3134 else
3135 {
3136 /* Use a global operator new. */
3137 /* See if a cookie might be required. */
3139 {
3141 /* No size arithmetic necessary, so the size check is
3142 not needed. */
3145 }
3151 }
3158 /* Now, check to see if this function is actually a placement
3159 allocation function. This can happen even when PLACEMENT is NULL
3160 because we might have something like:
3162 struct S { void* operator new (size_t, int i = 0); };
3164 A call to `new S' will get this allocation function, even though
3165 there is no explicit placement argument. If there is more than
3166 one argument, or there are variable arguments, then this is a
3167 placement allocation function. */
3168 placement_allocation_fn_p
3173 && !placement_allocation_fn_p
3178 {
3181 {
3187 }
3188 }
3190 /* If we found a simple case of PLACEMENT_EXPR above, then copy it
3191 into a temporary variable. */
3197 {
3203 {
3207 }
3211 {
3212 /* Attempt to make the warning point at the operator new argument. */
3217 }
3218 }
3220 /* In the simple case, we can stop now. */
3225 /* Store the result of the allocation call in a variable so that we can
3226 use it more than once. */
3230 /* Strip any COMPOUND_EXPRs from ALLOC_CALL. */
3234 /* Preevaluate the placement args so that we don't reevaluate them for a
3235 placement delete. */
3237 {
3238 tree inits;
3242 alloc_expr);
3243 }
3245 /* unless an allocation function is declared with an empty excep-
3246 tion-specification (_except.spec_), throw(), it indicates failure to
3247 allocate storage by throwing a bad_alloc exception (clause _except_,
3248 _lib.bad.alloc_); it returns a non-null pointer otherwise If the allo-
3249 cation function is declared with an empty exception-specification,
3250 throw(), it returns null to indicate failure to allocate storage and a
3251 non-null pointer otherwise.
3253 So check for a null exception spec on the op new we just called. */
3256 check_new
3260 {
3261 tree cookie;
3262 tree cookie_ptr;
3263 tree size_ptr_type;
3265 /* Adjust so we're pointing to the start of the object. */
3268 /* Store the number of bytes allocated so that we can know how
3269 many elements to destroy later. We use the last sizeof
3270 (size_t) bytes to store the number of elements. */
3281 {
3282 /* Also store the element size. */
3293 }
3294 }
3295 else
3296 {
3299 }
3301 /* Now use a pointer to the type we've actually allocated. */
3303 /* But we want to operate on a non-const version to start with,
3304 since we'll be modifying the elements. */
3305 non_const_pointer_type = build_pointer_type
3309 /* Any further uses of alloc_node will want this type, too. */
3312 /* Now initialize the allocated object. Note that we preevaluate the
3313 initialization expression, apart from the actual constructor call or
3314 assignment--we do this because we want to delay the allocation as long
3315 as possible in order to minimize the size of the exception region for
3316 placement delete. */
3318 {
3323 {
3326 }
3329 {
3330 /* build_value_init doesn't work in templates, and we don't need
3331 the initializer anyway since we're going to throw it away and
3332 rebuild it at instantiation time, so just build up a single
3333 constructor call to get any appropriate diagnostics. */
3337 complete_ctor_identifier,
3339 LOOKUP_NORMAL,
3340 complain);
3342 }
3344 {
3348 {
3352 else
3353 {
3357 complain);
3358 else
3359 /* We'll check the length at runtime. */
3363 }
3364 }
3366 {
3370 }
3371 init_expr
3375 integer_one_node,
3376 complain),
3377 vecinit,
3378 explicit_value_init_p,
3380 complain);
3382 /* An array initialization is stable because the initialization
3383 of each element is a full-expression, so the temporaries don't
3384 leak out. */
3386 }
3387 else
3388 {
3392 {
3394 complete_ctor_identifier,
3396 LOOKUP_NORMAL,
3397 complain);
3398 }
3400 {
3401 /* Something like `new int()'. NO_CLEANUP is needed so
3402 we don't try and build a (possibly ill-formed)
3403 destructor. */
3408 }
3409 else
3410 {
3411 tree ie;
3413 /* We are processing something like `new int (10)', which
3414 means allocate an int, and initialize it with 10. */
3417 complain);
3420 }
3421 /* If the initializer uses C++14 aggregate NSDMI that refer to the
3422 object being initialized, replace them now and don't try to
3423 preevaluate. */
3431 stable = (!had_placeholder
3433 }
3438 /* If any part of the object initialization terminates by throwing an
3439 exception and a suitable deallocation function can be found, the
3440 deallocation function is called to free the memory in which the
3441 object was being constructed, after which the exception continues
3442 to propagate in the context of the new-expression. If no
3443 unambiguous matching deallocation function can be found,
3444 propagating the exception does not cause the object's memory to be
3445 freed. */
3447 {
3449 tree cleanup;
3451 /* The Standard is unclear here, but the right thing to do
3452 is to use the same method for finding deallocation
3453 functions that we use for finding allocation functions. */
3454 cleanup = (build_op_delete_call
3456 alloc_node,
3457 size,
3458 globally_qualified_p,
3460 alloc_fn,
3461 complain));
3466 /* This is much simpler if we were able to preevaluate all of
3467 the arguments to the constructor call. */
3468 {
3469 /* CLEANUP is compiler-generated, so no diagnostics. */
3473 /* Likewise, this try-catch is compiler-generated. */
3475 }
3476 else
3477 /* Ack! First we allocate the memory. Then we set our sentry
3478 variable to true, and expand a cleanup that deletes the
3479 memory if sentry is true. Then we run the constructor, and
3480 finally clear the sentry.
3482 We need to do this because we allocate the space first, so
3483 if there are any temporaries with cleanups in the
3484 constructor args and we weren't able to preevaluate them, we
3485 need this EH region to extend until end of full-expression
3486 to preserve nesting. */
3487 {
3495 /* CLEANUP is compiler-generated, so no diagnostics. */
3505 init_expr
3508 end));
3509 /* Likewise, this is compiler-generated. */
3511 }
3512 }
3513 }
3514 else
3517 /* Now build up the return value in reverse order. */
3527 /* If we don't have an initializer or a cookie, strip the TARGET_EXPR
3528 and return the call (which doesn't need to be adjusted). */
3530 else
3531 {
3533 {
3536 nullptr_node,
3537 complain);
3540 }
3542 /* Perform the allocation before anything else, so that ALLOC_NODE
3543 has been initialized before we start using it. */
3545 }
3550 /* A new-expression is never an lvalue. */
3554 }
3556 /* Generate a representation for a C++ "new" expression. *PLACEMENT
3557 is a vector of placement-new arguments (or NULL if none). If NELTS
3558 is NULL, TYPE is the type of the storage to be allocated. If NELTS
3559 is not NULL, then this is an array-new allocation; TYPE is the type
3560 of the elements in the array and NELTS is the number of elements in
3561 the array. *INIT, if non-NULL, is the initializer for the new
3562 object, or an empty vector to indicate an initializer of "()". If
3563 USE_GLOBAL_NEW is true, then the user explicitly wrote "::new"
3564 rather than just "new". This may change PLACEMENT and INIT. */
3566 tree
3569 {
3570 tree rval;
3579 /* Don't do auto deduction where it might affect mangling. */
3581 {
3584 {
3587 {
3590 }
3592 }
3593 }
3596 {
3603 use_global_new);
3608 {
3610 /* Also copy any CONSTRUCTORs in *init, since reshape_init and
3611 digest_init clobber them in place. */
3613 {
3617 }
3618 }
3624 }
3627 {
3629 {
3632 else
3634 }
3636 /* Try to determine the constant value only for the purposes
3637 of the diagnostic below but continue to use the original
3638 value and handle const folding later. */
3641 /* The expression in a noptr-new-declarator is erroneous if it's of
3642 non-class type and its value before converting to std::size_t is
3643 less than zero. ... If the expression is a constant expression,
3644 the program is ill-fomed. */
3647 {
3651 }
3655 }
3657 /* ``A reference cannot be created by the new operator. A reference
3658 is not an object (8.2.2, 8.4.3), so a pointer to it could not be
3659 returned by new.'' ARM 5.3.3 */
3661 {
3664 else
3667 }
3670 {
3674 }
3676 /* The type allocated must be complete. If the new-type-id was
3677 "T[N]" then we are just checking that "T" is complete here, but
3678 that is equivalent, since the value of "N" doesn't matter. */
3687 {
3693 }
3695 /* Wrap it in a NOP_EXPR so warn_if_unused_value doesn't complain. */
3700 }
3701 \f
3702 static tree
3704 special_function_kind auto_delete_vec,
3706 {
3707 tree virtual_size;
3709 tree size_exp;
3711 /* Temporary variables used by the loop. */
3714 /* This is the body of the loop that implements the deletion of a
3715 single element, and moves temp variables to next elements. */
3716 tree body;
3718 /* This is the LOOP_EXPR that governs the deletion of the elements. */
3721 /* This is the thing that governs what to do after the loop has run. */
3724 /* This is the BIND_EXPR which holds the outermost iterator of the
3725 loop. It is convenient to set this variable up and test it before
3726 executing any other code in the loop.
3727 This is also the containing expression returned by this function. */
3729 tree tmp;
3731 /* We should only have 1-D arrays here. */
3738 {
3741 "possible problem detected in invocation of "
3743 {
3746 "class-specific operator delete [] will be called, "
3748 }
3749 /* This size won't actually be used. */
3752 }
3759 {
3760 /* Make sure the destructor is callable. */
3762 {
3765 complain);
3768 }
3770 }
3772 /* The below is short by the cookie size. */
3777 tbase_init
3781 base),
3782 virtual_size),
3783 complain);
3801 complain);
3809 no_destructor:
3810 /* Delete the storage if appropriate. */
3812 {
3813 tree base_tbd;
3815 /* The below is short by the cookie size. */
3820 /* no header */
3822 else
3823 {
3824 tree cookie_size;
3828 MINUS_EXPR,
3831 cookie_size,
3832 complain);
3836 /* True size with header. */
3838 }
3845 complain);
3846 }
3850 ;
3853 else
3854 /* The delete operator mist be called, even if a destructor
3855 throws. */
3861 /* Outermost wrapper: If pointer is null, punt. */
3864 /* This is a compiler generated comparison, don't emit
3865 e.g. -Wnonnull-compare warning for it. */
3873 {
3876 }
3879 /* Pre-evaluate the SAVE_EXPR outside of the BIND_EXPR. */
3883 }
3885 /* Create an unnamed variable of the indicated TYPE. */
3887 tree
3889 {
3890 tree decl;
3900 }
3902 /* Create a new temporary variable of the indicated TYPE, initialized
3903 to INIT.
3905 It is not entered into current_binding_level, because that breaks
3906 things when it comes time to do final cleanups (which take place
3907 "outside" the binding contour of the function). */
3909 tree
3911 {
3912 tree decl;
3921 }
3923 /* Subroutine of build_vec_init. Returns true if assigning to an array of
3924 INNER_ELT_TYPE from INIT is trivial. */
3926 static bool
3928 {
3933 }
3935 /* Subroutine of build_vec_init: Check that the array has at least N
3936 elements. Other parameters are local variables in build_vec_init. */
3938 void
3940 {
3943 {
3945 {
3947 nelts);
3951 }
3952 /* Don't check an array new when -fno-exceptions. */
3953 }
3956 {
3957 /* Make sure the last element of the initializer is in bounds. */
3958 finish_expr_stmt
3959 (ubsan_instrument_bounds
3961 }
3962 }
3964 /* `build_vec_init' returns tree structure that performs
3965 initialization of a vector of aggregate types.
3967 BASE is a reference to the vector, of ARRAY_TYPE, or a pointer
3968 to the first element, of POINTER_TYPE.
3969 MAXINDEX is the maximum index of the array (one less than the
3970 number of elements). It is only used if BASE is a pointer or
3971 TYPE_DOMAIN (TREE_TYPE (BASE)) == NULL_TREE.
3973 INIT is the (possibly NULL) initializer.
3975 If EXPLICIT_VALUE_INIT_P is true, then INIT must be NULL. All
3976 elements in the array are value-initialized.
3978 FROM_ARRAY is 0 if we should init everything with INIT
3979 (i.e., every element initialized from INIT).
3980 FROM_ARRAY is 1 if we should index into INIT in parallel
3981 with initialization of DECL.
3982 FROM_ARRAY is 2 if we should index into INIT in parallel,
3983 but use assignment instead of initialization. */
3985 tree
3989 {
3990 tree rval;
3993 tree iterator;
3994 /* The type of BASE. */
3996 /* The type of an element in the array. */
3998 /* The element type reached after removing all outer array
3999 types. */
4000 tree inner_elt_type;
4001 /* The type of a pointer to an element in the array. */
4002 tree ptype;
4003 tree stmt_expr;
4004 tree compound_stmt;
4027 /* Look through the TARGET_EXPR around a compound literal. */
4036 {
4039 {
4042 }
4043 }
4045 /* If we have a braced-init-list or string constant, make sure that the array
4046 is big enough for all the initializers. */
4061 || (same_type_ignoring_top_level_qualifiers_p
4063 /* Don't do this if the CONSTRUCTOR might contain something
4064 that might throw and require us to clean up. */
4068 {
4069 /* Do non-default initialization of trivial arrays resulting from
4070 brace-enclosed initializers. In this case, digest_init and
4071 store_constructor will handle the semantics for us. */
4077 }
4083 {
4089 }
4090 else
4093 /* The code we are generating looks like:
4094 ({
4095 T* t1 = (T*) base;
4096 T* rval = t1;
4097 ptrdiff_t iterator = maxindex;
4098 try {
4099 for (; iterator != -1; --iterator) {
4100 ... initialize *t1 ...
4101 ++t1;
4102 }
4103 } catch (...) {
4104 ... destroy elements that were constructed ...
4105 }
4106 rval;
4107 })
4109 We can omit the try and catch blocks if we know that the
4110 initialization will never throw an exception, or if the array
4111 elements do not have destructors. We can omit the loop completely if
4112 the elements of the array do not have constructors.
4114 We actually wrap the entire body of the above in a STMT_EXPR, for
4115 tidiness.
4117 When copying from array to another, when the array elements have
4118 only trivial copy constructors, we should use __builtin_memcpy
4119 rather than generating a loop. That way, we could take advantage
4120 of whatever cleverness the back end has for dealing with copies
4121 of blocks of memory. */
4130 /* If initializing one array from another, initialize element by
4131 element. We rely upon the below calls to do the argument
4132 checking. Evaluate the initializer before entering the try block. */
4134 {
4143 }
4145 /* Protect the entire array initialization so that we can destroy
4146 the partially constructed array if an exception is thrown.
4147 But don't do this if we're assigning. */
4150 {
4152 }
4154 /* Should we try to create a constant initializer? */
4158 : (type_has_constexpr_default_constructor
4164 /* If we're initializing a static array, we want to do static
4165 initialization of any elements with constant initializers even if
4166 some are non-constant. */
4172 /* Skip over the handling of non-empty init lists. */
4175 /* Maybe pull out constant value when from_array? */
4178 {
4179 /* Do non-default initialization of non-trivial arrays resulting from
4180 brace-enclosed initializers. */
4183 /* If the constructor already has the array type, it's been through
4184 digest_init, so we shouldn't try to do anything more. */
4195 {
4197 tree one_init;
4199 num_initialized_elts++;
4206 else
4212 {
4215 {
4219 else
4221 }
4222 else
4223 {
4225 {
4230 }
4232 }
4233 }
4240 complain);
4243 else
4247 complain);
4250 else
4252 }
4254 /* Any elements without explicit initializers get T{}. */
4256 }
4258 {
4259 /* Check that the array is at least as long as the string. */
4266 /* Copy the string to the first part of the array. */
4272 /* Adjust the counter and pointer. */
4281 /* And set the rest of the array to NUL. */
4284 }
4286 {
4291 {
4295 }
4296 }
4298 /* Now, default-initialize any remaining elements. We don't need to
4299 do that if a) the type does not need constructing, or b) we've
4300 already initialized all the elements.
4302 We do need to keep going if we're copying an array. */
4305 /* With a constexpr default constructor, which we checked for when
4306 setting try_const above, default-initialization is equivalent to
4307 value-initialization, and build_value_init gives us something more
4308 friendly to maybe_constant_init. */
4313 && (num_initialized_elts
4315 {
4316 /* If the ITERATOR is lesser or equal to -1, then we don't have to loop;
4317 we've already initialized all the elements. */
4318 tree for_stmt;
4319 tree elt_init;
4320 tree to;
4328 complain);
4335 /* If the initializer is {}, then all elements are initialized from T{}.
4336 But for non-classes, that's the same as value-initialization. */
4338 {
4340 {
4342 }
4343 else
4344 {
4347 }
4348 }
4351 {
4352 tree from;
4355 {
4361 }
4362 else
4375 complain);
4376 else
4378 }
4380 {
4382 {
4387 }
4388 else
4391 explicit_value_init_p,
4393 }
4395 {
4399 }
4400 else
4401 {
4405 else
4406 {
4409 complain);
4411 ? error_mark_node
4413 }
4414 }
4420 {
4421 /* FIXME refs to earlier elts */
4424 {
4426 /* Don't fill the CONSTRUCTOR with zeros. */
4430 }
4431 else
4432 {
4436 else
4438 }
4441 {
4444 {
4447 }
4448 }
4449 }
4457 complain));
4460 complain));
4463 }
4465 /* Make sure to cleanup any partially constructed elements. */
4468 {
4469 tree e;
4472 complain);
4474 /* Flatten multi-dimensional array since build_vec_delete only
4475 expects one-dimensional array. */
4479 /* Avoid mixing signed and unsigned. */
4482 complain);
4491 }
4493 /* The value of the array initialization is the array itself, RVAL
4494 is a pointer to the first element. */
4505 {
4507 {
4510 }
4513 else
4515 }
4517 /* Now make the result have the correct type. */
4519 {
4524 }
4527 }
4529 /* Call the DTOR_KIND destructor for EXP. FLAGS are as for
4530 build_delete. */
4532 static tree
4534 tsubst_flags_t complain)
4535 {
4536 tree name;
4537 tree fn;
4539 {
4554 }
4559 flags,
4561 complain);
4562 }
4564 /* Generate a call to a destructor. TYPE is the type to cast ADDR to.
4565 ADDR is an expression which yields the store to be destroyed.
4566 AUTO_DELETE is the name of the destructor to call, i.e., either
4567 sfk_complete_destructor, sfk_base_destructor, or
4568 sfk_deleting_destructor.
4570 FLAGS is the logical disjunction of zero or more LOOKUP_
4571 flags. See cp-tree.h for more info. */
4573 tree
4576 {
4577 tree expr;
4584 /* Can happen when CURRENT_EXCEPTION_OBJECT gets its type
4585 set to `error_mark_node' before it gets properly cleaned up. */
4593 {
4595 {
4599 }
4602 }
4605 {
4608 /* We don't want to warn about delete of void*, only other
4609 incomplete types. Deleting other incomplete types
4610 invokes undefined behavior, but it is not ill-formed, so
4611 compile to something that would even do The Right Thing
4612 (TM) should the type have a trivial dtor and no delete
4613 operator. */
4615 {
4618 {
4621 "possible problem detected in invocation of "
4623 {
4626 "neither the destructor nor the class-specific "
4627 "operator delete will be called, even if they are "
4629 }
4630 }
4634 {
4637 {
4640 "deleting object of abstract class type %qT"
4641 " which has non-virtual destructor"
4643 else
4645 "deleting object of polymorphic class type %qT"
4646 " which has non-virtual destructor"
4648 }
4649 }
4650 }
4654 /* Throw away const and volatile on target type of addr. */
4656 }
4657 else
4658 {
4659 /* Don't check PROTECT here; leave that decision to the
4660 destructor. If the destructor is accessible, call it,
4661 else report error. */
4669 }
4672 {
4673 /* Make sure the destructor is callable. */
4675 {
4680 }
4687 use_global_delete,
4690 complain);
4691 }
4692 else
4693 {
4696 tree ifexp;
4701 /* For `::delete x', we must not use the deleting destructor
4702 since then we would not be sure to get the global `operator
4703 delete'. */
4705 {
4706 /* We will use ADDR multiple times so we must save it. */
4709 /* Delete the object. */
4711 head,
4716 complain);
4717 /* Otherwise, treat this like a complete object destructor
4718 call. */
4720 }
4721 /* If the destructor is non-virtual, there is no deleting
4722 variant. Instead, we must explicitly call the appropriate
4723 `operator delete' here. */
4726 {
4727 /* We will use ADDR multiple times so we must save it. */
4729 /* Build the call. */
4731 addr,
4736 complain);
4737 /* Call the complete object destructor. */
4739 }
4742 {
4743 /* Make sure we have access to the member op delete, even though
4744 we'll actually be calling it from the destructor. */
4749 complain);
4750 }
4757 /* The delete operator must be called, regardless of whether
4758 the destructor throws.
4760 [expr.delete]/7 The deallocation function is called
4761 regardless of whether the destructor for the object or some
4762 element of the array throws an exception. */
4765 /* We need to calculate this before the dtor changes the vptr. */
4770 /* Explicit destructor call; don't check for null pointer. */
4772 else
4773 {
4774 /* Handle deleting a null pointer. */
4780 /* This is a compiler generated comparison, don't emit
4781 e.g. -Wnonnull-compare warning for it. */
4784 }
4790 }
4791 }
4793 /* At the beginning of a destructor, push cleanups that will call the
4794 destructors for our base classes and members.
4796 Called from begin_destructor_body. */
4798 void
4800 {
4803 tree member;
4804 tree expr;
4807 /* Run destructors for all virtual baseclasses. */
4810 {
4811 tree cond = (condition_conversion
4813 current_in_charge_parm,
4814 integer_two_node)));
4816 /* The CLASSTYPE_VBASECLASSES vector is in initialization
4817 order, which is also the right order for pushing cleanups. */
4820 {
4822 {
4824 base_dtor_identifier,
4825 NULL,
4826 base_binfo,
4827 (LOOKUP_NORMAL
4829 tf_warning_or_error);
4831 {
4835 }
4836 }
4837 }
4838 }
4840 /* Take care of the remaining baseclasses. */
4843 {
4849 base_dtor_identifier,
4852 tf_warning_or_error);
4855 }
4857 /* Don't automatically destroy union members. */
4863 {
4872 {
4873 tree this_member = (build_class_member_access_expr
4877 tf_warning_or_error));
4879 sfk_complete_destructor,
4884 }
4885 }
4886 }
4888 /* Build a C++ vector delete expression.
4889 MAXINDEX is the number of elements to be deleted.
4890 ELT_SIZE is the nominal size of each element in the vector.
4891 BASE is the expression that should yield the store to be deleted.
4892 This function expands (or synthesizes) these calls itself.
4893 AUTO_DELETE_VEC says whether the container (vector) should be deallocated.
4895 This also calls delete for virtual baseclasses of elements of the vector.
4897 Update: MAXINDEX is no longer needed. The size can be extracted from the
4898 start of the vector for pointers, and from the type for arrays. We still
4899 use MAXINDEX for arrays because it happens to already have one of the
4900 values we'd have to extract. (We could use MAXINDEX with pointers to
4901 confirm the size, and trap if the numbers differ; not clear that it'd
4902 be worth bothering.) */
4904 tree
4906 special_function_kind auto_delete_vec,
4908 {
4909 tree type;
4910 tree rval;
4916 {
4917 /* Step back one from start of vector, and read dimension. */
4918 tree cookie_addr;
4923 {
4926 }
4931 cookie_addr);
4933 }
4935 {
4936 /* Get the total number of things in the array, maxindex is a
4937 bad name. */
4944 {
4947 }
4948 }
4949 else
4950 {
4954 }
4962 }