| blob | b558742abf65f62dc093a3c23120e06afa5acece |
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 {
584 /* Do deferred instantiation of the NSDMI. */
585 init = (tsubst_copy_and_build
596 {
600 }
604 }
605 }
606 else
610 {
612 {
617 }
619 }
622 {
625 }
626 else
627 {
628 /* Use a PLACEHOLDER_EXPR when we don't have a 'this' parameter to
629 refer to; constexpr evaluation knows what to do with it. */
632 }
634 /* Strip redundant TARGET_EXPR so we don't need to remap it, and
635 so the aggregate init code below will see a CONSTRUCTOR. */
641 /* Now put it back so C++17 copy elision works. */
647 }
649 /* Diagnose the flexible array MEMBER if its INITializer is non-null
650 and return true if so. Otherwise return false. */
652 bool
654 {
662 /* Point at the flexible array member declaration if it's initialized
663 in-class, and at the ctor if it's initialized in a ctor member
664 initializer list. */
665 location_t loc;
667 || !current_function_decl
670 else
675 }
677 /* Initialize MEMBER, a FIELD_DECL, with INIT, a TREE_LIST of
678 arguments. If TREE_LIST is void_type_node, an empty initializer
679 list was given; if NULL_TREE no initializer was given. */
681 static void
683 {
684 tree decl;
687 /* Use the non-static data member initializer if there was no
688 mem-initializer for this field. */
695 /* Effective C++ rule 12 requires that all data members be
696 initialized. */
700 member);
702 /* Get an lvalue for the data member. */
706 tf_warning_or_error);
712 {
714 /* Handle references. */
721 member);
722 }
725 {
726 /* mem() means value-initialization. */
728 {
732 }
733 else
734 {
740 }
741 }
742 /* Deal with this here, as we will get confused if we try to call the
743 assignment op for an anonymous union. This can happen in a
744 synthesized copy constructor. */
746 {
748 {
751 }
752 }
755 /* Pre-digested NSDMI. */
758 /* { } mem-initializer. */
763 {
764 /* With references and list-initialization, we need to deal with
765 extending temporary lifetimes. 12.2p5: "A temporary bound to a
766 reference member in a constructor’s ctor-initializer (12.6.2)
767 persists until the constructor exits." */
772 tf_warning_or_error);
774 {
779 }
782 /* A FIELD_DECL doesn't really have a suitable lifetime, but
783 make_temporary_var_for_ref_to_temp will treat it as automatic and
784 set_up_extended_ref_temp wants to use the decl in a warning. */
794 }
797 {
799 {
801 {
802 /* Check to make sure the member initializer is valid and
803 something like a CONSTRUCTOR in: T a[] = { 1, 2 } and
804 if it isn't, return early to avoid triggering another
805 error below. */
811 else
816 }
820 {
822 {
823 /* Initialize the array only if it's not a flexible
824 array member (i.e., if it has an upper bound). */
828 }
829 }
830 else
832 }
833 else
834 {
841 {
842 /* TYPE_NEEDS_CONSTRUCTING can be set just because we have a
843 vtable; still give this diagnostic. */
848 }
850 tf_warning_or_error));
851 }
852 }
853 else
854 {
856 {
857 tree core_type;
858 /* member traversal: note it leaves init NULL */
860 {
865 }
867 {
872 }
882 }
884 /* There was an explicit member initialization. Do some work
885 in that case. */
887 tf_warning_or_error);
889 /* Reject a member initializer for a flexible array member. */
893 tf_warning_or_error));
894 }
897 {
898 tree expr;
903 tf_warning_or_error);
906 tf_warning_or_error);
911 }
912 }
914 /* Returns a TREE_LIST containing (as the TREE_PURPOSE of each node) all
915 the FIELD_DECLs on the TYPE_FIELDS list for T, in reverse order. */
917 static tree
919 {
920 tree fields;
922 /* Note whether or not T is a union. */
927 {
928 tree fieldtype;
930 /* Skip CONST_DECLs for enumeration constants and so forth. */
936 /* For an anonymous struct or union, we must recursively
937 consider the fields of the anonymous type. They can be
938 directly initialized from the constructor. */
940 {
941 /* Add this field itself. Synthesized copy constructors
942 initialize the entire aggregate. */
944 /* And now add the fields in the anonymous aggregate. */
947 }
948 /* Add this field. */
951 }
954 }
956 /* Return the innermost aggregate scope for FIELD, whether that is
957 the enclosing class or an anonymous aggregate within it. */
959 static tree
961 {
964 else
966 }
968 /* The MEM_INITS are a TREE_LIST. The TREE_PURPOSE of each list gives
969 a FIELD_DECL or BINFO in T that needs initialization. The
970 TREE_VALUE gives the initializer, or list of initializer arguments.
972 Return a TREE_LIST containing all of the initializations required
973 for T, in the order in which they should be performed. The output
974 list has the same format as the input. */
976 static tree
978 {
979 tree init;
981 tree sorted_inits;
982 tree next_subobject;
987 /* Build up a list of initializations. The TREE_PURPOSE of entry
988 will be the subobject (a FIELD_DECL or BINFO) to initialize. The
989 TREE_VALUE will be the constructor arguments, or NULL if no
990 explicit initialization was provided. */
993 /* Process the virtual bases. */
998 /* Process the direct bases. */
1004 /* Process the non-static data members. */
1006 /* Reverse the entire list of initializations, so that they are in
1007 the order that they will actually be performed. */
1010 /* If the user presented the initializers in an order different from
1011 that in which they will actually occur, we issue a warning. Keep
1012 track of the next subobject which can be explicitly initialized
1013 without issuing a warning. */
1016 /* Go through the explicit initializers, filling in TREE_PURPOSE in
1017 the SORTED_INITS. */
1019 {
1020 tree subobject;
1021 tree subobject_init;
1025 /* If the explicit initializers are in sorted order, then
1026 SUBOBJECT will be NEXT_SUBOBJECT, or something following
1027 it. */
1029 subobject_init;
1034 /* Issue a warning if the explicit initializer order does not
1035 match that which will actually occur.
1036 ??? Are all these on the correct lines? */
1038 {
1043 else
1049 else
1053 }
1055 /* Look again, from the beginning of the list. */
1057 {
1061 }
1063 /* It is invalid to initialize the same subobject more than
1064 once. */
1066 {
1070 subobject);
1071 else
1074 subobject);
1075 }
1077 /* Record the initialization. */
1080 }
1082 /* [class.base.init]
1084 If a ctor-initializer specifies more than one mem-initializer for
1085 multiple members of the same union (including members of
1086 anonymous unions), the ctor-initializer is ill-formed.
1088 Here we also splice out uninitialized union members. */
1090 {
1094 {
1095 tree field;
1096 tree ctx;
1102 /* Skip base classes. */
1106 /* If this is an anonymous aggregate with no explicit initializer,
1107 splice it out. */
1111 /* See if this field is a member of a union, or a member of a
1112 structure contained in a union, etc. */
1115 /* If this field is not a member of a union, skip it. */
1120 /* If this union member has no explicit initializer and no NSDMI,
1121 splice it out. */
1124 else
1127 /* It's only an error if we have two initializers for the same
1128 union type. */
1130 {
1133 }
1135 /* See if LAST_FIELD and the field initialized by INIT are
1136 members of the same union (or the union itself). If so, there's
1137 a problem, unless they're actually members of the same structure
1138 which is itself a member of a union. For example, given:
1140 union { struct { int i; int j; }; };
1142 initializing both `i' and `j' makes sense. */
1143 ctx = common_enclosing_class
1149 {
1150 /* A mem-initializer hides an NSDMI. */
1155 else
1156 {
1159 ctx);
1161 }
1162 }
1166 next:
1169 splice:
1172 }
1173 }
1176 }
1178 /* Callback for cp_walk_tree to mark all PARM_DECLs in a tree as read. */
1180 static tree
1182 {
1187 }
1189 /* Initialize all bases and members of CURRENT_CLASS_TYPE. MEM_INITS
1190 is a TREE_LIST giving the explicit mem-initializer-list for the
1191 constructor. The TREE_PURPOSE of each entry is a subobject (a
1192 FIELD_DECL or a BINFO) of the CURRENT_CLASS_TYPE. The TREE_VALUE
1193 is a TREE_LIST giving the arguments to the constructor or
1194 void_type_node for an empty list of arguments. */
1196 void
1198 {
1201 /* We will already have issued an error message about the fact that
1202 the type is incomplete. */
1209 {
1210 /* Delegating constructor. */
1214 }
1220 /* Sort the mem-initializers into the order in which the
1221 initializations should be performed. */
1226 /* Initialize base classes. */
1230 {
1234 /* We already have issued an error message. */
1238 /* Suppress access control when calling the inherited ctor. */
1240 && flag_new_inheriting_ctors
1246 {
1247 /* If these initializations are taking place in a copy constructor,
1248 the base class should probably be explicitly initialized if there
1249 is a user-defined constructor in the base class (other than the
1250 default constructor, which will be called anyway). */
1258 }
1260 /* Initialize the base. */
1262 {
1263 tree base_addr;
1269 arguments,
1270 flags,
1271 tf_warning_or_error);
1273 }
1275 /* C++14 DR1658 Means we do not have to construct vbases of
1276 abstract classes. */
1278 else
1279 /* When not constructing vbases of abstract classes, at least mark
1280 the arguments expressions as read to avoid
1281 -Wunused-but-set-parameter false positives. */
1286 }
1289 /* Initialize the vptrs. */
1292 /* Initialize the data members. */
1294 {
1298 }
1299 }
1301 /* Returns the address of the vtable (i.e., the value that should be
1302 assigned to the vptr) for BINFO. */
1304 tree
1306 {
1308 tree vtbl;
1311 /* If this is a virtual primary base, then the vtable we want to store
1312 is that for the base this is being used as the primary base of. We
1313 can't simply skip the initialization, because we may be expanding the
1314 inits of a subobject constructor where the virtual base layout
1315 can be different. */
1319 /* Figure out what vtable BINFO's vtable is based on, and mark it as
1320 used. */
1324 /* Now compute the address to use when initializing the vptr. */
1330 }
1332 /* This code sets up the virtual function tables appropriate for
1333 the pointer DECL. It is a one-ply initialization.
1335 BINFO is the exact type that DECL is supposed to be. In
1336 multiple inheritance, this might mean "C's A" if C : A, B. */
1338 static void
1340 {
1342 tree vtt_index;
1344 /* Compute the initializer for vptr. */
1347 /* We may get this vptr from a VTT, if this is a subobject
1348 constructor or subobject destructor. */
1351 {
1352 tree vtbl2;
1353 tree vtt_parm;
1355 /* Compute the value to use, when there's a VTT. */
1361 /* The actual initializer is the VTT value only in the subobject
1362 constructor. In maybe_clone_body we'll substitute NULL for
1363 the vtt_parm in the case of the non-subobject constructor. */
1365 }
1367 /* Compute the location of the vtpr. */
1372 /* Assign the vtable to the vptr. */
1376 }
1378 /* If an exception is thrown in a constructor, those base classes already
1379 constructed must be destroyed. This function creates the cleanup
1380 for BINFO, which has just been constructed. If FLAG is non-NULL,
1381 it is a DECL which is nonzero when this base needs to be
1382 destroyed. */
1384 static void
1386 {
1387 tree expr;
1392 /* Call the destructor. */
1394 base_dtor_identifier,
1395 NULL,
1396 binfo,
1398 tf_warning_or_error);
1410 }
1412 /* Construct the virtual base-class VBASE passing the ARGUMENTS to its
1413 constructor. */
1415 static void
1417 {
1418 tree inner_if_stmt;
1419 tree exp;
1420 tree flag;
1422 /* If there are virtual base classes with destructors, we need to
1423 emit cleanups to destroy them if an exception is thrown during
1424 the construction process. These exception regions (i.e., the
1425 period during which the cleanups must occur) begin from the time
1426 the construction is complete to the end of the function. If we
1427 create a conditional block in which to initialize the
1428 base-classes, then the cleanup region for the virtual base begins
1429 inside a block, and ends outside of that block. This situation
1430 confuses the sjlj exception-handling code. Therefore, we do not
1431 create a single conditional block, but one for each
1432 initialization. (That way the cleanup regions always begin
1433 in the outer block.) We trust the back end to figure out
1434 that the FLAG will not change across initializations, and
1435 avoid doing multiple tests. */
1440 /* Compute the location of the virtual base. If we're
1441 constructing virtual bases, then we must be the most derived
1442 class. Therefore, we don't have to look up the virtual base;
1443 we already know where it is. */
1452 }
1454 /* Find the context in which this FIELD can be initialized. */
1456 static tree
1458 {
1461 /* Anonymous union members can be initialized in the first enclosing
1462 non-anonymous union context. */
1466 }
1468 /* Function to give error message if member initialization specification
1469 is erroneous. FIELD is the member we decided to initialize.
1470 TYPE is the type for which the initialization is being performed.
1471 FIELD must be a member of TYPE.
1473 MEMBER_NAME is the name of the member. */
1475 static int
1477 {
1481 {
1483 member_name);
1485 }
1487 {
1490 field);
1492 }
1494 {
1498 }
1500 {
1502 member_name);
1504 }
1507 }
1509 /* NAME is a FIELD_DECL, an IDENTIFIER_NODE which names a field, or it
1510 is a _TYPE node or TYPE_DECL which names a base for that type.
1511 Check the validity of NAME, and return either the base _TYPE, base
1512 binfo, or the FIELD_DECL of the member. If NAME is invalid, return
1513 NULL_TREE and issue a diagnostic.
1515 An old style unnamed direct single base construction is permitted,
1516 where NAME is NULL. */
1518 tree
1520 {
1521 tree basetype;
1522 tree field;
1528 {
1529 /* This is an obsolete unnamed base class initializer. The
1530 parser will already have warned about its use. */
1532 {
1535 current_class_type);
1538 basetype = BINFO_TYPE
1543 current_class_type);
1545 }
1546 }
1548 {
1551 }
1554 else
1558 {
1559 tree class_binfo;
1560 tree direct_binfo;
1561 tree virtual_binfo;
1572 /* Look for a direct base. */
1577 /* Look for a virtual base -- unless the direct base is itself
1578 virtual. */
1582 /* [class.base.init]
1584 If a mem-initializer-id is ambiguous because it designates
1585 both a direct non-virtual base class and an inherited virtual
1586 base class, the mem-initializer is ill-formed. */
1588 {
1590 basetype);
1592 }
1595 {
1599 else
1603 }
1606 }
1607 else
1608 {
1611 else
1616 }
1619 }
1621 /* This is like `expand_member_init', only it stores one aggregate
1622 value into another.
1624 INIT comes in two flavors: it is either a value which
1625 is to be stored in EXP, or it is a parameter list
1626 to go to a constructor, which will operate on EXP.
1627 If INIT is not a parameter list for a constructor, then set
1628 LOOKUP_ONLYCONVERTING.
1629 If FLAGS is LOOKUP_ONLYCONVERTING then it is the = init form of
1630 the initializer, if FLAGS is 0, then it is the (init) form.
1631 If `init' is a CONSTRUCTOR, then we emit a warning message,
1632 explaining that such initializations are invalid.
1634 If INIT resolves to a CALL_EXPR which happens to return
1635 something of the type we are looking for, then we know
1636 that we can safely use that call to perform the
1637 initialization.
1639 The virtual function table pointer cannot be set up here, because
1640 we do not really know its type.
1642 This never calls operator=().
1644 When initializing, nothing is CONST.
1646 A default copy constructor may have to be used to perform the
1647 initialization.
1649 A constructor or a conversion operator may have to be used to
1650 perform the initialization, but not both, as it would be ambiguous. */
1652 tree
1654 {
1655 tree stmt_expr;
1656 tree compound_stmt;
1666 location_t init_loc = (init
1674 {
1679 {
1683 {
1684 /* Wrap the initializer in a CONSTRUCTOR so that build_vec_init
1685 recognizes it as direct-initialization. */
1689 }
1690 }
1691 else
1692 {
1693 /* Must arrange to initialize each element of EXP
1694 from elements of INIT. */
1703 && (!from_array
1705 /* Can happen, eg, handling the compound-literals
1706 extension (ext/complit12.C). */
1708 {
1713 }
1714 }
1718 from_array,
1719 complain);
1723 /* Restore the type of init unless it was used directly. */
1727 }
1749 /* Just know that we've seen something for this node. */
1753 }
1755 static void
1757 tsubst_flags_t complain)
1758 {
1761 /* It fails because there may not be a constructor which takes
1762 its own type as the first (or only parameter), but which does
1763 take other types via a conversion. So, if the thing initializing
1764 the expression is a unit element of type X, first try X(X&),
1765 followed by initialization by X. If neither of these work
1766 out, then look hard. */
1767 tree rval;
1770 /* If we have direct-initialization from an initializer list, pull
1771 it out of the TREE_LIST so the code below can see it. */
1774 {
1778 /* Only call reshape_init if it has not been called earlier
1779 by the callers. */
1782 }
1786 /* A brace-enclosed initializer for an aggregate. In C++0x this can
1787 happen for direct-initialization, too. */
1790 /* A CONSTRUCTOR of the target's type is a previously digested
1791 initializer, whether that happened just above or in
1792 cp_parser_late_parsing_nsdmi.
1794 A TARGET_EXPR with TARGET_EXPR_DIRECT_INIT_P or TARGET_EXPR_LIST_INIT_P
1795 set represents the whole initialization, so we shouldn't build up
1796 another ctor call. */
1803 {
1804 /* Early initialization via a TARGET_EXPR only works for
1805 complete objects. */
1812 }
1816 {
1817 /* Base subobjects should only get direct-initialization. */
1821 /* Do nothing. We hit this in two cases: Reference initialization,
1822 where we aren't initializing a real variable, so we don't want
1823 to run a new constructor; and catching an exception, where we
1824 have already built up the constructor call so we could wrap it
1826 else
1831 /* We need to protect the initialization of a catch parm with a
1832 call to terminate(), which shows up as a MUST_NOT_THROW_EXPR
1833 around the TARGET_EXPR for the copy constructor. See
1834 initialize_handler_parm. */
1835 {
1839 }
1840 else
1845 }
1850 {
1854 }
1855 else
1860 {
1861 /* Delegating constructor. */
1862 tree complete;
1863 tree base;
1866 /* Unshare the arguments for the second call. */
1869 {
1872 }
1875 complain);
1881 complain);
1884 }
1885 else
1886 {
1891 complain);
1892 }
1898 {
1901 {
1905 }
1906 }
1908 /* FIXME put back convert_to_void? */
1911 }
1913 /* This function is responsible for initializing EXP with INIT
1914 (if any).
1916 BINFO is the binfo of the type for who we are performing the
1917 initialization. For example, if W is a virtual base class of A and B,
1918 and C : A, B.
1919 If we are initializing B, then W must contain B's W vtable, whereas
1920 were we initializing C, W must contain C's W vtable.
1922 TRUE_EXP is nonzero if it is the true expression being initialized.
1923 In this case, it may be EXP, or may just contain EXP. The reason we
1924 need this is because if EXP is a base element of TRUE_EXP, we
1925 don't necessarily know by looking at EXP where its virtual
1926 baseclass fields should really be pointing. But we do know
1927 from TRUE_EXP. In constructors, we don't know anything about
1928 the value being initialized.
1930 FLAGS is just passed to `build_new_method_call'. See that function
1931 for its description. */
1933 static void
1935 tsubst_flags_t complain)
1936 {
1942 /* Use a function returning the desired type to initialize EXP for us.
1943 If the function is a constructor, and its first argument is
1944 NULL_TREE, know that it was meant for us--just slide exp on
1945 in and expand the constructor. Constructors now come
1946 as TARGET_EXPRs. */
1950 {
1952 /* If store_init_value returns NULL_TREE, the INIT has been
1953 recorded as the DECL_INITIAL for EXP. That means there's
1954 nothing more we have to do. */
1960 }
1962 /* List-initialization from {} becomes value-initialization for non-aggregate
1963 classes with default constructors. Handle this here when we're
1964 initializing a base, so protected access works. */
1966 {
1973 }
1975 /* If an explicit -- but empty -- initializer list was present,
1976 that's value-initialization. */
1978 {
1979 /* If the type has data but no user-provided ctor, we need to zero
1980 out the object. */
1983 {
1986 /* Don't clobber already initialized virtual bases. */
1989 field_size);
1992 }
1994 /* If we don't need to mess with the constructor at all,
1995 then we're done. */
1999 /* Otherwise fall through and call the constructor. */
2001 }
2003 /* We know that expand_default_init can handle everything we want
2004 at this point. */
2006 }
2008 /* Report an error if TYPE is not a user-defined, class type. If
2009 OR_ELSE is nonzero, give an error message. */
2011 int
2013 {
2018 {
2022 }
2024 }
2026 tree
2028 {
2034 else
2036 }
2038 /* Build a reference to a member of an aggregate. This is not a C++
2039 `&', but really something which can have its address taken, and
2040 then act as a pointer to member, for example TYPE :: FIELD can have
2041 its address taken by saying & TYPE :: FIELD. ADDRESS_P is true if
2042 this expression is the operand of "&".
2044 @@ Prints out lousy diagnostics for operator <typename>
2045 @@ fields.
2047 @@ This function should be rewritten and placed in search.c. */
2049 tree
2051 tsubst_flags_t complain)
2052 {
2053 tree decl;
2056 /* class templates can come in as TEMPLATE_DECLs here. */
2069 /* Callers should call mark_used before this point. */
2074 {
2078 }
2080 /* Entities other than non-static members need no further
2081 processing. */
2088 {
2092 }
2094 /* Set up BASEBINFO for member lookup. */
2097 /* A lot of this logic is now handled in lookup_member. */
2099 {
2100 /* Go from the TREE_BASELINK to the member function info. */
2104 {
2105 /* Get rid of a potential OVERLOAD around it. */
2108 /* Unique functions are handled easily. */
2110 /* For non-static member of base class, we need a special rule
2111 for access checking [class.protected]:
2113 If the access is to form a pointer to member, the
2114 nested-name-specifier shall name the derived class
2115 (or any class derived from that class). */
2120 complain);
2121 else
2123 complain);
2129 }
2130 else
2132 }
2134 {
2135 /* We need additional test besides the one in
2136 check_accessibility_of_qualified_id in case it is
2137 a pointer to non-static member. */
2139 complain))
2141 }
2144 {
2145 /* If MEMBER is non-static, then the program has fallen afoul of
2146 [expr.prim]:
2148 An id-expression that denotes a nonstatic data member or
2149 nonstatic member function of a class can only be used:
2151 -- as part of a class member access (_expr.ref_) in which the
2152 object-expression refers to the member's class or a class
2153 derived from that class, or
2155 -- to form a pointer to member (_expr.unary.op_), or
2157 -- in the body of a nonstatic member function of that class or
2158 of a class derived from that class (_class.mfct.nonstatic_), or
2160 -- in a mem-initializer for a constructor for that class or for
2161 a class derived from that class (_class.base.init_). */
2163 {
2164 /* Build a representation of the qualified name suitable
2165 for use as the operand to "&" -- even though the "&" is
2166 not actually present. */
2168 /* In Microsoft mode, treat a non-static member function as if
2169 it were a pointer-to-member. */
2171 {
2174 }
2179 }
2181 {
2185 }
2187 }
2192 }
2194 /* If DECL is a scalar enumeration constant or variable with a
2195 constant initializer, return the initializer (or, its initializers,
2196 recursively); otherwise, return DECL. If STRICT_P, the
2197 initializer is only returned if DECL is a
2198 constant-expression. If RETURN_AGGREGATE_CST_OK_P, it is ok to
2199 return an aggregate constant. */
2201 static tree
2203 {
2208 {
2209 tree init;
2210 /* If DECL is a static data member in a template
2211 specialization, we must instantiate it here. The
2212 initializer for the static data member is not processed
2213 until needed; we need it now. */
2217 {
2220 /* Treat the error as a constant to avoid cascading errors on
2221 excessively recursive template instantiation (c++/9335). */
2223 else
2225 }
2226 /* Initializers in templates are generally expanded during
2227 instantiation, so before that for const int i(2)
2228 INIT is a TREE_LIST with the actual initializer as
2229 TREE_VALUE. */
2231 && init
2235 /* Instantiate a non-dependent initializer for user variables. We
2236 mustn't do this for the temporary for an array compound literal;
2237 trying to instatiate the initializer will keep creating new
2238 temporaries until we crash. Probably it's not useful to do it for
2239 other artificial variables, either. */
2245 || (!return_aggregate_cst_ok_p
2246 /* Unless RETURN_AGGREGATE_CST_OK_P is true, do not
2247 return an aggregate constant (of which string
2248 literals are a special case), as we do not want
2249 to make inadvertent copies of such entities, and
2250 we must be sure that their addresses are the
2251 same everywhere. */
2255 /* Don't return a CONSTRUCTOR for a variable with partial run-time
2256 initialization, since it doesn't represent the entire value. */
2260 /* If the variable has a dynamic initializer, don't use its
2261 DECL_INITIAL which doesn't reflect the real value. */
2268 }
2270 }
2272 /* If DECL is a CONST_DECL, or a constant VAR_DECL initialized by constant
2273 of integral or enumeration type, or a constexpr variable of scalar type,
2274 then return that value. These are those variables permitted in constant
2275 expressions by [5.19/1]. */
2277 tree
2279 {
2282 }
2284 /* Like scalar_constant_value, but can also return aggregate initializers. */
2286 tree
2288 {
2291 }
2293 /* A more relaxed version of scalar_constant_value, used by the
2294 common C/C++ code. */
2296 tree
2298 {
2301 }
2302 \f
2303 /* Common subroutines of build_new and build_vec_delete. */
2304 \f
2305 /* Build and return a NEW_EXPR. If NELTS is non-NULL, TYPE[NELTS] is
2306 the type of the object being allocated; otherwise, it's just TYPE.
2307 INIT is the initializer, if any. USE_GLOBAL_NEW is true if the
2308 user explicitly wrote "::operator new". PLACEMENT, if non-NULL, is
2309 a vector of arguments to be provided as arguments to a placement
2310 new operator. This routine performs no semantic checks; it just
2311 creates and returns a NEW_EXPR. */
2313 static tree
2316 {
2317 tree init_list;
2318 tree new_expr;
2320 /* If INIT is NULL, the we want to store NULL_TREE in the NEW_EXPR.
2321 If INIT is not NULL, then we want to store VOID_ZERO_NODE. This
2322 permits us to distinguish the case of a missing initializer "new
2323 int" from an empty initializer "new int()". */
2328 else
2329 {
2334 }
2338 init_list);
2343 }
2345 /* Diagnose uninitialized const members or reference members of type
2346 TYPE. USING_NEW is used to disambiguate the diagnostic between a
2347 new expression without a new-initializer and a declaration. Returns
2348 the error count. */
2350 static int
2353 {
2354 tree field;
2361 {
2362 tree field_type;
2373 {
2376 {
2378 {
2382 else
2384 }
2385 else
2386 {
2391 else
2394 }
2397 }
2398 }
2401 {
2404 {
2406 {
2410 else
2412 }
2413 else
2414 {
2419 else
2422 }
2425 }
2426 }
2429 error_count
2432 }
2434 }
2436 int
2438 {
2440 }
2442 /* Call __cxa_bad_array_new_length to indicate that the size calculation
2443 overflowed. Pretend it returns sizetype so that it plays nicely in the
2444 COND_EXPR. */
2446 tree
2448 {
2450 {
2455 fn = push_throw_library_fn
2457 }
2460 }
2462 /* Attempt to find the initializer for flexible array field T in the
2463 initializer INIT, when non-null. Returns the initializer when
2464 successful and NULL otherwise. */
2465 static tree
2467 {
2474 /* Iterate over all top-level initializer elements. */
2476 /* If the member T is found, return it. */
2481 }
2483 /* Attempt to verify that the argument, OPER, of a placement new expression
2484 refers to an object sufficiently large for an object of TYPE or an array
2485 of NELTS of such objects when NELTS is non-null, and issue a warning when
2486 it does not. SIZE specifies the size needed to construct the object or
2487 array and captures the result of NELTS * sizeof (TYPE). (SIZE could be
2488 greater when the array under construction requires a cookie to store
2489 NELTS. GCC's placement new expression stores the cookie when invoking
2490 a user-defined placement new operator function but not the default one.
2491 Placement new expressions with user-defined placement new operator are
2492 not diagnosed since we don't know how they use the buffer (this could
2493 be a future extension). */
2494 static void
2496 {
2499 /* The number of bytes to add to or subtract from the size of the provided
2500 buffer based on an offset into an array or an array element reference.
2501 Although intermediate results may be negative (as in a[3] - 2) a valid
2502 final result cannot be. */
2504 /* True when the size of the entire destination object should be used
2505 to compute the possibly optimistic estimate of the available space. */
2507 /* True when the reference to the destination buffer is an ADDR_EXPR. */
2512 /* Using a function argument or a (non-array) variable as an argument
2513 to placement new is not checked since it's unknown what it might
2514 point to. */
2520 /* Evaluate any constant expressions. */
2523 /* Handle the common case of array + offset expression when the offset
2524 is a constant. */
2526 {
2527 /* If the offset is compile-time constant, use it to compute a more
2528 accurate estimate of the size of the buffer. Since the operand
2529 of POINTER_PLUS_EXPR is represented as an unsigned type, convert
2530 it to signed first.
2531 Otherwise, use the size of the entire array as an optimistic
2532 estimate (this may lead to false negatives). */
2536 else
2542 }
2547 {
2550 }
2556 {
2557 /* Similar to the offset computed above, see if the array index
2558 is a compile-time constant. If so, and unless the offset was
2559 not a compile-time constant, use the index to determine the
2560 size of the buffer. Otherwise, use the entire array as
2561 an optimistic estimate of the size. */
2565 else
2566 {
2569 }
2572 }
2574 /* Refers to the declared object that constains the subobject referenced
2575 by OPER. When the object is initialized, makes it possible to determine
2576 the actual size of a flexible array member used as the buffer passed
2577 as OPER to placement new. */
2579 /* True when operand is a COMPONENT_REF, to distinguish flexible array
2580 members from arrays of unspecified size. */
2583 /* For COMPONENT_REF (i.e., a struct member) the size of the entire
2584 enclosing struct. Used to validate the adjustment (offset) into
2585 an array at the end of a struct. */
2588 /* Descend into a struct or union to find the member whose address
2589 is being used as the argument. */
2591 {
2600 }
2607 {
2608 /* A possibly optimistic estimate of the number of bytes available
2609 in the destination buffer. */
2611 /* True when the estimate above is in fact the exact size
2612 of the destination buffer rather than an estimate. */
2615 /* Treat members of unions and members of structs uniformly, even
2616 though the size of a member of a union may be viewed as extending
2617 to the end of the union itself (it is by __builtin_object_size). */
2621 {
2622 /* Use the size of the entire array object when the expression
2623 refers to a variable or its size depends on an expression
2624 that's not a compile-time constant. */
2627 }
2629 {
2630 /* Use the size of the type of the destination buffer object
2631 as the optimistic estimate of the available space in it.
2632 Use the maximum possible size for zero-size arrays and
2633 flexible array members (except of initialized objects
2634 thereof). */
2637 }
2640 {
2642 {
2643 /* Constructing into a buffer provided by the flexible array
2644 member of a declared object (which is permitted as a G++
2645 extension). If the array member has been initialized,
2646 determine its size from the initializer. Otherwise,
2647 the array size is zero. */
2651 }
2652 else
2655 }
2660 {
2665 && !var_decl
2668 }
2670 /* Reduce the size of the buffer by the adjustment computed above
2671 from the offset and/or the index into the array. */
2674 else
2675 {
2679 {
2683 }
2684 }
2686 /* The minimum amount of space needed for the allocation. This
2687 is an optimistic estimate that makes it possible to detect
2688 placement new invocation for some undersize buffers but not
2689 others. */
2690 offset_int bytes_need;
2699 else
2700 {
2701 /* The type is a VLA. */
2703 }
2706 {
2710 exact_size ?
2711 "placement new constructing an object of type "
2712 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2713 "and size %qwi"
2715 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2719 else
2721 exact_size ?
2722 "placement new constructing an array of objects "
2723 "of type %qT and size %qwu in a region of type %qT "
2724 "and size %qwi"
2726 "of type %qT and size %qwu in a region of type %qT "
2730 else
2732 exact_size ?
2733 "placement new constructing an object of type %qT "
2734 "and size %qwu in a region of type %qT and size %qwi"
2736 "and size %qwu in a region of type %qT and size "
2740 }
2741 }
2742 }
2744 /* True if alignof(T) > __STDCPP_DEFAULT_NEW_ALIGNMENT__. */
2746 bool
2748 {
2751 }
2753 /* Return the alignment we expect malloc to guarantee. This should just be
2754 MALLOC_ABI_ALIGNMENT, but that macro defaults to only BITS_PER_WORD for some
2755 reason, so don't let the threshold be smaller than max_align_t_align. */
2757 unsigned
2759 {
2761 }
2763 /* Determine whether an allocation function is a namespace-scope
2764 non-replaceable placement new function. See DR 1748.
2765 TODO: Enable in all standard modes. */
2766 static bool
2768 {
2770 {
2775 }
2777 }
2779 /* Generate code for a new-expression, including calling the "operator
2780 new" function, initializing the object, and, if an exception occurs
2781 during construction, cleaning up. The arguments are as for
2782 build_raw_new_expr. This may change PLACEMENT and INIT.
2783 TYPE is the type of the object being constructed, possibly an array
2784 of NELTS elements when NELTS is non-null (in "new T[NELTS]", T may
2785 be an array of the form U[inner], with the whole expression being
2786 "new U[NELTS][inner]"). */
2788 static tree
2791 tsubst_flags_t complain)
2792 {
2794 /* True iff this is a call to "operator new[]" instead of just
2795 "operator new". */
2797 /* If ARRAY_P is true, the element type of the array. This is never
2798 an ARRAY_TYPE; for something like "new int[3][4]", the
2799 ELT_TYPE is "int". If ARRAY_P is false, this is the same type as
2800 TYPE. */
2801 tree elt_type;
2802 /* The type of the new-expression. (This type is always a pointer
2803 type.) */
2804 tree pointer_type;
2805 tree non_const_pointer_type;
2806 /* The most significant array bound in int[OUTER_NELTS][inner]. */
2808 /* For arrays with a non-constant number of elements, a bounds checks
2809 on the NELTS parameter to avoid integer overflow at runtime. */
2812 /* Number of the "inner" elements in "new T[OUTER_NELTS][inner]". */
2815 /* Size of the inner array elements (those with constant dimensions). */
2816 offset_int inner_size;
2817 /* The address returned by the call to "operator new". This node is
2818 a VAR_DECL and is therefore reusable. */
2819 tree alloc_node;
2820 tree alloc_fn;
2823 /* If non-NULL, the number of extra bytes to allocate at the
2824 beginning of the storage allocated for an array-new expression in
2825 order to store the number of elements. */
2827 tree placement_first;
2829 /* True if the function we are calling is a placement allocation
2830 function. */
2832 /* True if the storage must be initialized, either by a constructor
2833 or due to an explicit new-initializer. */
2835 /* The address of the thing allocated, not including any cookie. In
2836 particular, if an array cookie is in use, DATA_ADDR is the
2837 address of the first array element. This node is a VAR_DECL, and
2838 is therefore reusable. */
2839 tree data_addr;
2844 {
2847 }
2849 {
2850 /* Transforms new (T[N]) to new T[N]. The former is a GNU
2851 extension for variable N. (This also covers new T where T is
2852 a VLA typedef.) */
2858 }
2860 /* Lots of logic below. depends on whether we have a constant number of
2861 elements, so go ahead and fold it now. */
2865 /* If our base type is an array, then make sure we know how many elements
2866 it has. */
2870 {
2874 {
2879 {
2883 }
2885 }
2886 else
2887 {
2889 {
2893 }
2895 }
2899 inner_nelts_cst,
2900 complain);
2901 }
2904 {
2907 }
2912 /* Warn if we performed the (T[N]) to T[N] transformation and N is
2913 variable. */
2916 {
2918 {
2925 }
2926 else
2928 }
2931 {
2935 }
2943 {
2945 /* A program that calls for default-initialization [...] of an
2946 entity of reference type is ill-formed. */
2950 /* A new-expression that creates an object of type T initializes
2951 that object as follows:
2952 - If the new-initializer is omitted:
2953 -- If T is a (possibly cv-qualified) non-POD class type
2954 (or array thereof), the object is default-initialized (8.5).
2955 [...]
2956 -- Otherwise, the object created has indeterminate
2957 value. If T is a const-qualified type, or a (possibly
2958 cv-qualified) POD class type (or array thereof)
2959 containing (directly or indirectly) a member of
2960 const-qualified type, the program is ill-formed; */
2970 }
2974 {
2978 }
2982 {
2983 /* Maximum available size in bytes. Half of the address space
2984 minus the cookie size. */
2985 offset_int max_size
2987 /* Maximum number of outer elements which can be allocated. */
2988 offset_int max_outer_nelts;
2989 tree max_outer_nelts_tree;
2995 /* Unconditionally subtract the cookie size. This decreases the
2996 maximum object size and is safe even if we choose not to use
2997 a cookie after all. */
3003 {
3007 }
3015 {
3017 {
3018 /* When the array size is constant, check it at compile time
3019 to make sure it doesn't exceed the implementation-defined
3020 maximum, as required by C++ 14 (in C++ 11 this requirement
3021 isn't explicitly stated but it's enforced anyway -- see
3022 grokdeclarator in cp/decl.c). */
3026 }
3027 }
3028 else
3029 {
3030 /* When a runtime check is necessary because the array size
3031 isn't constant, keep only the top-most seven bits (starting
3032 with the most significant non-zero bit) of the maximum size
3033 to compare the array size against, to simplify encoding the
3034 constant maximum size in the instruction stream. */
3041 outer_nelts,
3042 max_outer_nelts_tree);
3043 }
3044 }
3052 /* If PLACEMENT is a single simple pointer type not passed by
3053 reference, prepare to capture it in a temporary variable. Do
3054 this now, since PLACEMENT will change in the calls below. */
3062 /* Allocate the object. */
3063 tree fnname;
3064 tree fns;
3068 member_new_p = !globally_qualified_p
3070 && (array_p
3075 {
3076 /* Use a class-specific operator new. */
3077 /* If a cookie is required, add some extra space. */
3080 else
3081 {
3083 /* No size arithmetic necessary, so the size check is
3084 not needed. */
3087 }
3088 /* Perform the overflow check. */
3095 /* Create the argument list. */
3097 /* Do name-lookup to find the appropriate operator. */
3100 {
3104 }
3106 {
3108 {
3111 }
3113 }
3117 {
3120 alloc_call
3124 /* If no matching function is found and the allocated object type
3125 has new-extended alignment, the alignment argument is removed
3126 from the argument list, and overload resolution is performed
3127 again. */
3130 }
3134 LOOKUP_NORMAL,
3136 }
3137 else
3138 {
3139 /* Use a global operator new. */
3140 /* See if a cookie might be required. */
3142 {
3144 /* No size arithmetic necessary, so the size check is
3145 not needed. */
3148 }
3154 }
3161 /* Now, check to see if this function is actually a placement
3162 allocation function. This can happen even when PLACEMENT is NULL
3163 because we might have something like:
3165 struct S { void* operator new (size_t, int i = 0); };
3167 A call to `new S' will get this allocation function, even though
3168 there is no explicit placement argument. If there is more than
3169 one argument, or there are variable arguments, then this is a
3170 placement allocation function. */
3171 placement_allocation_fn_p
3176 && !placement_allocation_fn_p
3181 {
3184 {
3190 }
3191 }
3193 /* If we found a simple case of PLACEMENT_EXPR above, then copy it
3194 into a temporary variable. */
3200 {
3206 {
3210 }
3214 {
3215 /* Attempt to make the warning point at the operator new argument. */
3220 }
3221 }
3223 /* In the simple case, we can stop now. */
3228 /* Store the result of the allocation call in a variable so that we can
3229 use it more than once. */
3233 /* Strip any COMPOUND_EXPRs from ALLOC_CALL. */
3237 /* Preevaluate the placement args so that we don't reevaluate them for a
3238 placement delete. */
3240 {
3241 tree inits;
3245 alloc_expr);
3246 }
3248 /* unless an allocation function is declared with an empty excep-
3249 tion-specification (_except.spec_), throw(), it indicates failure to
3250 allocate storage by throwing a bad_alloc exception (clause _except_,
3251 _lib.bad.alloc_); it returns a non-null pointer otherwise If the allo-
3252 cation function is declared with an empty exception-specification,
3253 throw(), it returns null to indicate failure to allocate storage and a
3254 non-null pointer otherwise.
3256 So check for a null exception spec on the op new we just called. */
3259 check_new
3263 {
3264 tree cookie;
3265 tree cookie_ptr;
3266 tree size_ptr_type;
3268 /* Adjust so we're pointing to the start of the object. */
3271 /* Store the number of bytes allocated so that we can know how
3272 many elements to destroy later. We use the last sizeof
3273 (size_t) bytes to store the number of elements. */
3284 {
3285 /* Also store the element size. */
3296 }
3297 }
3298 else
3299 {
3302 }
3304 /* Now use a pointer to the type we've actually allocated. */
3306 /* But we want to operate on a non-const version to start with,
3307 since we'll be modifying the elements. */
3308 non_const_pointer_type = build_pointer_type
3312 /* Any further uses of alloc_node will want this type, too. */
3315 /* Now initialize the allocated object. Note that we preevaluate the
3316 initialization expression, apart from the actual constructor call or
3317 assignment--we do this because we want to delay the allocation as long
3318 as possible in order to minimize the size of the exception region for
3319 placement delete. */
3321 {
3326 {
3329 }
3332 {
3333 /* build_value_init doesn't work in templates, and we don't need
3334 the initializer anyway since we're going to throw it away and
3335 rebuild it at instantiation time, so just build up a single
3336 constructor call to get any appropriate diagnostics. */
3340 complete_ctor_identifier,
3342 LOOKUP_NORMAL,
3343 complain);
3345 }
3347 {
3351 {
3355 else
3356 {
3360 complain);
3361 else
3362 /* We'll check the length at runtime. */
3366 }
3367 }
3369 {
3373 }
3374 init_expr
3378 integer_one_node,
3379 complain),
3380 vecinit,
3381 explicit_value_init_p,
3383 complain);
3385 /* An array initialization is stable because the initialization
3386 of each element is a full-expression, so the temporaries don't
3387 leak out. */
3389 }
3390 else
3391 {
3395 {
3397 complete_ctor_identifier,
3399 LOOKUP_NORMAL,
3400 complain);
3401 }
3403 {
3404 /* Something like `new int()'. NO_CLEANUP is needed so
3405 we don't try and build a (possibly ill-formed)
3406 destructor. */
3411 }
3412 else
3413 {
3414 tree ie;
3416 /* We are processing something like `new int (10)', which
3417 means allocate an int, and initialize it with 10. */
3420 complain);
3423 }
3424 /* If the initializer uses C++14 aggregate NSDMI that refer to the
3425 object being initialized, replace them now and don't try to
3426 preevaluate. */
3434 stable = (!had_placeholder
3436 }
3441 /* If any part of the object initialization terminates by throwing an
3442 exception and a suitable deallocation function can be found, the
3443 deallocation function is called to free the memory in which the
3444 object was being constructed, after which the exception continues
3445 to propagate in the context of the new-expression. If no
3446 unambiguous matching deallocation function can be found,
3447 propagating the exception does not cause the object's memory to be
3448 freed. */
3450 {
3452 tree cleanup;
3454 /* The Standard is unclear here, but the right thing to do
3455 is to use the same method for finding deallocation
3456 functions that we use for finding allocation functions. */
3457 cleanup = (build_op_delete_call
3459 alloc_node,
3460 size,
3461 globally_qualified_p,
3463 alloc_fn,
3464 complain));
3469 /* This is much simpler if we were able to preevaluate all of
3470 the arguments to the constructor call. */
3471 {
3472 /* CLEANUP is compiler-generated, so no diagnostics. */
3476 /* Likewise, this try-catch is compiler-generated. */
3478 }
3479 else
3480 /* Ack! First we allocate the memory. Then we set our sentry
3481 variable to true, and expand a cleanup that deletes the
3482 memory if sentry is true. Then we run the constructor, and
3483 finally clear the sentry.
3485 We need to do this because we allocate the space first, so
3486 if there are any temporaries with cleanups in the
3487 constructor args and we weren't able to preevaluate them, we
3488 need this EH region to extend until end of full-expression
3489 to preserve nesting. */
3490 {
3498 /* CLEANUP is compiler-generated, so no diagnostics. */
3508 init_expr
3511 end));
3512 /* Likewise, this is compiler-generated. */
3514 }
3515 }
3516 }
3517 else
3520 /* Now build up the return value in reverse order. */
3530 /* If we don't have an initializer or a cookie, strip the TARGET_EXPR
3531 and return the call (which doesn't need to be adjusted). */
3533 else
3534 {
3536 {
3539 nullptr_node,
3540 complain);
3543 }
3545 /* Perform the allocation before anything else, so that ALLOC_NODE
3546 has been initialized before we start using it. */
3548 }
3553 /* A new-expression is never an lvalue. */
3557 }
3559 /* Generate a representation for a C++ "new" expression. *PLACEMENT
3560 is a vector of placement-new arguments (or NULL if none). If NELTS
3561 is NULL, TYPE is the type of the storage to be allocated. If NELTS
3562 is not NULL, then this is an array-new allocation; TYPE is the type
3563 of the elements in the array and NELTS is the number of elements in
3564 the array. *INIT, if non-NULL, is the initializer for the new
3565 object, or an empty vector to indicate an initializer of "()". If
3566 USE_GLOBAL_NEW is true, then the user explicitly wrote "::new"
3567 rather than just "new". This may change PLACEMENT and INIT. */
3569 tree
3572 {
3573 tree rval;
3582 /* Don't do auto deduction where it might affect mangling. */
3584 {
3587 {
3590 {
3593 }
3595 }
3596 }
3599 {
3606 use_global_new);
3611 {
3613 /* Also copy any CONSTRUCTORs in *init, since reshape_init and
3614 digest_init clobber them in place. */
3616 {
3620 }
3621 }
3627 }
3630 {
3632 {
3635 else
3637 }
3639 /* Try to determine the constant value only for the purposes
3640 of the diagnostic below but continue to use the original
3641 value and handle const folding later. */
3644 /* The expression in a noptr-new-declarator is erroneous if it's of
3645 non-class type and its value before converting to std::size_t is
3646 less than zero. ... If the expression is a constant expression,
3647 the program is ill-fomed. */
3650 {
3654 }
3658 }
3660 /* ``A reference cannot be created by the new operator. A reference
3661 is not an object (8.2.2, 8.4.3), so a pointer to it could not be
3662 returned by new.'' ARM 5.3.3 */
3664 {
3667 else
3670 }
3673 {
3677 }
3679 /* The type allocated must be complete. If the new-type-id was
3680 "T[N]" then we are just checking that "T" is complete here, but
3681 that is equivalent, since the value of "N" doesn't matter. */
3690 {
3696 }
3698 /* Wrap it in a NOP_EXPR so warn_if_unused_value doesn't complain. */
3703 }
3704 \f
3705 static tree
3707 special_function_kind auto_delete_vec,
3709 {
3710 tree virtual_size;
3712 tree size_exp;
3714 /* Temporary variables used by the loop. */
3717 /* This is the body of the loop that implements the deletion of a
3718 single element, and moves temp variables to next elements. */
3719 tree body;
3721 /* This is the LOOP_EXPR that governs the deletion of the elements. */
3724 /* This is the thing that governs what to do after the loop has run. */
3727 /* This is the BIND_EXPR which holds the outermost iterator of the
3728 loop. It is convenient to set this variable up and test it before
3729 executing any other code in the loop.
3730 This is also the containing expression returned by this function. */
3732 tree tmp;
3734 /* We should only have 1-D arrays here. */
3741 {
3744 "possible problem detected in invocation of "
3746 {
3749 "class-specific operator delete [] will be called, "
3751 }
3752 /* This size won't actually be used. */
3755 }
3762 {
3763 /* Make sure the destructor is callable. */
3765 {
3768 complain);
3771 }
3773 }
3775 /* The below is short by the cookie size. */
3780 tbase_init
3784 base),
3785 virtual_size),
3786 complain);
3804 complain);
3812 no_destructor:
3813 /* Delete the storage if appropriate. */
3815 {
3816 tree base_tbd;
3818 /* The below is short by the cookie size. */
3823 /* no header */
3825 else
3826 {
3827 tree cookie_size;
3831 MINUS_EXPR,
3834 cookie_size,
3835 complain);
3839 /* True size with header. */
3841 }
3848 complain);
3849 }
3853 ;
3856 else
3857 /* The delete operator mist be called, even if a destructor
3858 throws. */
3864 /* Outermost wrapper: If pointer is null, punt. */
3867 /* This is a compiler generated comparison, don't emit
3868 e.g. -Wnonnull-compare warning for it. */
3876 {
3879 }
3882 /* Pre-evaluate the SAVE_EXPR outside of the BIND_EXPR. */
3886 }
3888 /* Create an unnamed variable of the indicated TYPE. */
3890 tree
3892 {
3893 tree decl;
3903 }
3905 /* Create a new temporary variable of the indicated TYPE, initialized
3906 to INIT.
3908 It is not entered into current_binding_level, because that breaks
3909 things when it comes time to do final cleanups (which take place
3910 "outside" the binding contour of the function). */
3912 tree
3914 {
3915 tree decl;
3924 }
3926 /* Subroutine of build_vec_init. Returns true if assigning to an array of
3927 INNER_ELT_TYPE from INIT is trivial. */
3929 static bool
3931 {
3936 }
3938 /* Subroutine of build_vec_init: Check that the array has at least N
3939 elements. Other parameters are local variables in build_vec_init. */
3941 void
3943 {
3946 {
3948 {
3950 nelts);
3954 }
3955 /* Don't check an array new when -fno-exceptions. */
3956 }
3959 {
3960 /* Make sure the last element of the initializer is in bounds. */
3961 finish_expr_stmt
3962 (ubsan_instrument_bounds
3964 }
3965 }
3967 /* `build_vec_init' returns tree structure that performs
3968 initialization of a vector of aggregate types.
3970 BASE is a reference to the vector, of ARRAY_TYPE, or a pointer
3971 to the first element, of POINTER_TYPE.
3972 MAXINDEX is the maximum index of the array (one less than the
3973 number of elements). It is only used if BASE is a pointer or
3974 TYPE_DOMAIN (TREE_TYPE (BASE)) == NULL_TREE.
3976 INIT is the (possibly NULL) initializer.
3978 If EXPLICIT_VALUE_INIT_P is true, then INIT must be NULL. All
3979 elements in the array are value-initialized.
3981 FROM_ARRAY is 0 if we should init everything with INIT
3982 (i.e., every element initialized from INIT).
3983 FROM_ARRAY is 1 if we should index into INIT in parallel
3984 with initialization of DECL.
3985 FROM_ARRAY is 2 if we should index into INIT in parallel,
3986 but use assignment instead of initialization. */
3988 tree
3992 {
3993 tree rval;
3996 tree iterator;
3997 /* The type of BASE. */
3999 /* The type of an element in the array. */
4001 /* The element type reached after removing all outer array
4002 types. */
4003 tree inner_elt_type;
4004 /* The type of a pointer to an element in the array. */
4005 tree ptype;
4006 tree stmt_expr;
4007 tree compound_stmt;
4030 /* Look through the TARGET_EXPR around a compound literal. */
4039 {
4042 {
4045 }
4046 }
4048 /* If we have a braced-init-list or string constant, make sure that the array
4049 is big enough for all the initializers. */
4064 || (same_type_ignoring_top_level_qualifiers_p
4066 /* Don't do this if the CONSTRUCTOR might contain something
4067 that might throw and require us to clean up. */
4071 {
4072 /* Do non-default initialization of trivial arrays resulting from
4073 brace-enclosed initializers. In this case, digest_init and
4074 store_constructor will handle the semantics for us. */
4080 }
4086 {
4092 }
4093 else
4096 /* The code we are generating looks like:
4097 ({
4098 T* t1 = (T*) base;
4099 T* rval = t1;
4100 ptrdiff_t iterator = maxindex;
4101 try {
4102 for (; iterator != -1; --iterator) {
4103 ... initialize *t1 ...
4104 ++t1;
4105 }
4106 } catch (...) {
4107 ... destroy elements that were constructed ...
4108 }
4109 rval;
4110 })
4112 We can omit the try and catch blocks if we know that the
4113 initialization will never throw an exception, or if the array
4114 elements do not have destructors. We can omit the loop completely if
4115 the elements of the array do not have constructors.
4117 We actually wrap the entire body of the above in a STMT_EXPR, for
4118 tidiness.
4120 When copying from array to another, when the array elements have
4121 only trivial copy constructors, we should use __builtin_memcpy
4122 rather than generating a loop. That way, we could take advantage
4123 of whatever cleverness the back end has for dealing with copies
4124 of blocks of memory. */
4133 /* If initializing one array from another, initialize element by
4134 element. We rely upon the below calls to do the argument
4135 checking. Evaluate the initializer before entering the try block. */
4137 {
4146 }
4148 /* Protect the entire array initialization so that we can destroy
4149 the partially constructed array if an exception is thrown.
4150 But don't do this if we're assigning. */
4153 {
4155 }
4157 /* Should we try to create a constant initializer? */
4161 : (type_has_constexpr_default_constructor
4167 /* If we're initializing a static array, we want to do static
4168 initialization of any elements with constant initializers even if
4169 some are non-constant. */
4175 /* Skip over the handling of non-empty init lists. */
4178 /* Maybe pull out constant value when from_array? */
4181 {
4182 /* Do non-default initialization of non-trivial arrays resulting from
4183 brace-enclosed initializers. */
4186 /* If the constructor already has the array type, it's been through
4187 digest_init, so we shouldn't try to do anything more. */
4198 {
4200 tree one_init;
4202 num_initialized_elts++;
4209 else
4215 {
4218 {
4222 else
4224 }
4225 else
4226 {
4228 {
4233 }
4235 }
4236 }
4243 complain);
4246 else
4250 complain);
4253 else
4255 }
4257 /* Any elements without explicit initializers get T{}. */
4259 }
4261 {
4262 /* Check that the array is at least as long as the string. */
4269 /* Copy the string to the first part of the array. */
4275 /* Adjust the counter and pointer. */
4284 /* And set the rest of the array to NUL. */
4287 }
4289 {
4294 {
4298 }
4299 }
4301 /* Now, default-initialize any remaining elements. We don't need to
4302 do that if a) the type does not need constructing, or b) we've
4303 already initialized all the elements.
4305 We do need to keep going if we're copying an array. */
4308 /* With a constexpr default constructor, which we checked for when
4309 setting try_const above, default-initialization is equivalent to
4310 value-initialization, and build_value_init gives us something more
4311 friendly to maybe_constant_init. */
4316 && (num_initialized_elts
4318 {
4319 /* If the ITERATOR is lesser or equal to -1, then we don't have to loop;
4320 we've already initialized all the elements. */
4321 tree for_stmt;
4322 tree elt_init;
4323 tree to;
4331 complain);
4338 /* If the initializer is {}, then all elements are initialized from T{}.
4339 But for non-classes, that's the same as value-initialization. */
4341 {
4343 {
4345 }
4346 else
4347 {
4350 }
4351 }
4354 {
4355 tree from;
4358 {
4364 }
4365 else
4378 complain);
4379 else
4381 }
4383 {
4385 {
4390 }
4391 else
4394 explicit_value_init_p,
4396 }
4398 {
4402 }
4403 else
4404 {
4408 else
4409 {
4412 complain);
4414 ? error_mark_node
4416 }
4417 }
4423 {
4424 /* FIXME refs to earlier elts */
4427 {
4429 /* Don't fill the CONSTRUCTOR with zeros. */
4433 }
4434 else
4435 {
4439 else
4441 }
4444 {
4447 {
4450 }
4451 }
4452 }
4460 complain));
4463 complain));
4466 }
4468 /* Make sure to cleanup any partially constructed elements. */
4471 {
4472 tree e;
4475 complain);
4477 /* Flatten multi-dimensional array since build_vec_delete only
4478 expects one-dimensional array. */
4482 /* Avoid mixing signed and unsigned. */
4485 complain);
4494 }
4496 /* The value of the array initialization is the array itself, RVAL
4497 is a pointer to the first element. */
4508 {
4510 {
4513 }
4516 else
4518 }
4520 /* Now make the result have the correct type. */
4522 {
4527 }
4530 }
4532 /* Call the DTOR_KIND destructor for EXP. FLAGS are as for
4533 build_delete. */
4535 static tree
4537 tsubst_flags_t complain)
4538 {
4539 tree name;
4541 {
4556 }
4561 flags,
4562 complain);
4563 }
4565 /* Generate a call to a destructor. TYPE is the type to cast ADDR to.
4566 ADDR is an expression which yields the store to be destroyed.
4567 AUTO_DELETE is the name of the destructor to call, i.e., either
4568 sfk_complete_destructor, sfk_base_destructor, or
4569 sfk_deleting_destructor.
4571 FLAGS is the logical disjunction of zero or more LOOKUP_
4572 flags. See cp-tree.h for more info. */
4574 tree
4577 {
4578 tree expr;
4585 /* Can happen when CURRENT_EXCEPTION_OBJECT gets its type
4586 set to `error_mark_node' before it gets properly cleaned up. */
4594 {
4596 {
4600 }
4603 }
4609 {
4612 /* We don't want to warn about delete of void*, only other
4613 incomplete types. Deleting other incomplete types
4614 invokes undefined behavior, but it is not ill-formed, so
4615 compile to something that would even do The Right Thing
4616 (TM) should the type have a trivial dtor and no delete
4617 operator. */
4619 {
4622 {
4625 "possible problem detected in invocation of "
4627 {
4630 "neither the destructor nor the class-specific "
4631 "operator delete will be called, even if they are "
4633 }
4634 }
4638 {
4641 {
4644 "deleting object of abstract class type %qT"
4645 " which has non-virtual destructor"
4647 else
4649 "deleting object of polymorphic class type %qT"
4650 " which has non-virtual destructor"
4652 }
4653 }
4654 }
4656 /* Throw away const and volatile on target type of addr. */
4658 }
4659 else
4660 {
4661 /* Don't check PROTECT here; leave that decision to the
4662 destructor. If the destructor is accessible, call it,
4663 else report error. */
4669 }
4672 /* We will use ADDR multiple times so we must save it. */
4677 {
4681 }
4687 {
4688 /* Leave do_delete null. */
4689 }
4690 /* For `::delete x', we must not use the deleting destructor
4691 since then we would not be sure to get the global `operator
4692 delete'. */
4694 {
4696 /* Delete the object. */
4698 head,
4703 complain);
4704 /* Otherwise, treat this like a complete object destructor
4705 call. */
4707 }
4708 /* If the destructor is non-virtual, there is no deleting
4709 variant. Instead, we must explicitly call the appropriate
4710 `operator delete' here. */
4712 {
4713 /* Build the call. */
4715 addr,
4720 complain);
4721 /* Call the complete object destructor. */
4723 }
4725 {
4726 /* Make sure we have access to the member op delete, even though
4727 we'll actually be calling it from the destructor. */
4732 complain);
4733 }
4738 else
4749 /* The delete operator must be called, regardless of whether
4750 the destructor throws.
4752 [expr.delete]/7 The deallocation function is called
4753 regardless of whether the destructor for the object or some
4754 element of the array throws an exception. */
4757 /* We need to calculate this before the dtor changes the vptr. */
4761 /* Handle deleting a null pointer. */
4769 /* This is a compiler generated comparison, don't emit
4770 e.g. -Wnonnull-compare warning for it. */
4778 }
4780 /* At the beginning of a destructor, push cleanups that will call the
4781 destructors for our base classes and members.
4783 Called from begin_destructor_body. */
4785 void
4787 {
4790 tree member;
4791 tree expr;
4794 /* Run destructors for all virtual baseclasses. */
4797 {
4798 tree cond = (condition_conversion
4800 current_in_charge_parm,
4801 integer_two_node)));
4803 /* The CLASSTYPE_VBASECLASSES vector is in initialization
4804 order, which is also the right order for pushing cleanups. */
4807 {
4809 {
4811 base_dtor_identifier,
4812 NULL,
4813 base_binfo,
4814 (LOOKUP_NORMAL
4816 tf_warning_or_error);
4818 {
4822 }
4823 }
4824 }
4825 }
4827 /* Take care of the remaining baseclasses. */
4830 {
4836 base_dtor_identifier,
4839 tf_warning_or_error);
4842 }
4844 /* Don't automatically destroy union members. */
4850 {
4859 {
4860 tree this_member = (build_class_member_access_expr
4864 tf_warning_or_error));
4866 sfk_complete_destructor,
4871 }
4872 }
4873 }
4875 /* Build a C++ vector delete expression.
4876 MAXINDEX is the number of elements to be deleted.
4877 ELT_SIZE is the nominal size of each element in the vector.
4878 BASE is the expression that should yield the store to be deleted.
4879 This function expands (or synthesizes) these calls itself.
4880 AUTO_DELETE_VEC says whether the container (vector) should be deallocated.
4882 This also calls delete for virtual baseclasses of elements of the vector.
4884 Update: MAXINDEX is no longer needed. The size can be extracted from the
4885 start of the vector for pointers, and from the type for arrays. We still
4886 use MAXINDEX for arrays because it happens to already have one of the
4887 values we'd have to extract. (We could use MAXINDEX with pointers to
4888 confirm the size, and trap if the numbers differ; not clear that it'd
4889 be worth bothering.) */
4891 tree
4893 special_function_kind auto_delete_vec,
4895 {
4896 tree type;
4897 tree rval;
4903 {
4904 /* Step back one from start of vector, and read dimension. */
4905 tree cookie_addr;
4910 {
4913 }
4918 cookie_addr);
4920 }
4922 {
4923 /* Get the total number of things in the array, maxindex is a
4924 bad name. */
4931 {
4934 }
4935 }
4936 else
4937 {
4941 }
4949 }