| blob | 14335388a50d78b70cb78ab2c30d2945043d0b9d |
1 /* Handle initialization things in C++.
2 Copyright (C) 1987-2017 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com)
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
21 /* High-level class interface. */
52 /* We are about to generate some complex initialization code.
53 Conceptually, it is all a single expression. However, we may want
54 to include conditionals, loops, and other such statement-level
55 constructs. Therefore, we build the initialization code inside a
56 statement-expression. This function starts such an expression.
57 STMT_EXPR_P and COMPOUND_STMT_P are filled in by this function;
58 pass them back to finish_init_stmts when the expression is
59 complete. */
61 static bool
63 {
70 }
72 /* Finish out the statement-expression begun by the previous call to
73 begin_init_stmts. Returns the statement-expression itself. */
75 static tree
77 {
85 }
87 /* Constructors */
89 /* Called from initialize_vtbl_ptrs via dfs_walk. BINFO is the base
90 which we want to initialize the vtable pointer for, DATA is
91 TREE_LIST whose TREE_VALUE is the this ptr expression. */
93 static tree
95 {
100 {
104 tf_warning_or_error);
107 }
110 }
112 /* Initialize all the vtable pointers in the object pointed to by
113 ADDR. */
115 void
117 {
118 tree list;
119 tree type;
124 /* Walk through the hierarchy, initializing the vptr in each base
125 class. We do these in pre-order because we can't find the virtual
126 bases for a class until we've initialized the vtbl for that
127 class. */
129 }
131 /* Return an expression for the zero-initialization of an object with
132 type T. This expression will either be a constant (in the case
133 that T is a scalar), or a CONSTRUCTOR (in the case that T is an
134 aggregate), or NULL (in the case that T does not require
135 initialization). In either case, the value can be used as
136 DECL_INITIAL for a decl of the indicated TYPE; it is a valid static
137 initializer. If NELTS is non-NULL, and TYPE is an ARRAY_TYPE, NELTS
138 is the number of elements in the array. If STATIC_STORAGE_P is
139 TRUE, initializers are only generated for entities for which
140 zero-initialization does not simply mean filling the storage with
141 zero bytes. FIELD_SIZE, if non-NULL, is the bit size of the field,
142 subfields with bit positions at or above that bit size shouldn't
143 be added. Note that this only works when the result is assigned
144 to a base COMPONENT_REF; if we only have a pointer to the base subobject,
145 expand_assignment will end up clearing the full size of TYPE. */
147 static tree
149 tree field_size)
150 {
153 /* [dcl.init]
155 To zero-initialize an object of type T means:
157 -- if T is a scalar type, the storage is set to the value of zero
158 converted to T.
160 -- if T is a non-union class type, the storage for each nonstatic
161 data member and each base-class subobject is zero-initialized.
163 -- if T is a union type, the storage for its first data member is
164 zero-initialized.
166 -- if T is an array type, the storage for each element is
167 zero-initialized.
169 -- if T is a reference type, no initialization is performed. */
174 ;
176 /* In order to save space, we do not explicitly build initializers
177 for items that do not need them. GCC's semantics are that
178 items with static storage duration that are not otherwise
179 initialized are initialized to zero. */
180 ;
186 {
187 tree field;
190 /* Iterate over the fields, building initializations. */
192 {
199 /* Don't add virtual bases for base classes if they are beyond
200 the size of the current field, that means it is present
201 somewhere else in the object. */
203 {
208 }
210 /* Note that for class types there will be FIELD_DECLs
211 corresponding to base classes as well. Thus, iterating
212 over TYPE_FIELDs will result in correct initialization of
213 all of the subobjects. */
215 {
216 tree new_field_size
223 static_storage_p,
224 new_field_size);
227 }
229 /* For unions, only the first field is initialized. */
232 }
234 /* Build a constructor to contain the initializations. */
236 }
238 {
239 tree max_index;
242 /* Iterate over the array elements, building initializations. */
247 else
250 /* If we have an error_mark here, we should just return error mark
251 as we don't know the size of the array yet. */
256 /* A zero-sized array, which is accepted as an extension, will
257 have an upper bound of -1. */
259 {
260 constructor_elt ce;
262 /* If this is a one element array, we just use a regular init. */
265 else
267 max_index);
273 {
276 }
277 }
279 /* Build a constructor to contain the initializations. */
281 }
284 else
287 /* In all cases, the initializer is a constant. */
292 }
294 /* Return an expression for the zero-initialization of an object with
295 type T. This expression will either be a constant (in the case
296 that T is a scalar), or a CONSTRUCTOR (in the case that T is an
297 aggregate), or NULL (in the case that T does not require
298 initialization). In either case, the value can be used as
299 DECL_INITIAL for a decl of the indicated TYPE; it is a valid static
300 initializer. If NELTS is non-NULL, and TYPE is an ARRAY_TYPE, NELTS
301 is the number of elements in the array. If STATIC_STORAGE_P is
302 TRUE, initializers are only generated for entities for which
303 zero-initialization does not simply mean filling the storage with
304 zero bytes. */
306 tree
308 {
310 }
312 /* Return a suitable initializer for value-initializing an object of type
313 TYPE, as described in [dcl.init]. */
315 tree
317 {
318 /* [dcl.init]
320 To value-initialize an object of type T means:
322 - if T is a class type (clause 9) with either no default constructor
323 (12.1) or a default constructor that is user-provided or deleted,
324 then the object is default-initialized;
326 - if T is a (possibly cv-qualified) class type without a user-provided
327 or deleted default constructor, then the object is zero-initialized
328 and the semantic constraints for default-initialization are checked,
329 and if T has a non-trivial default constructor, the object is
330 default-initialized;
332 - if T is an array type, then each element is value-initialized;
334 - otherwise, the object is zero-initialized.
336 A program that calls for default-initialization or
337 value-initialization of an entity of reference type is ill-formed. */
339 /* The AGGR_INIT_EXPR tweaking below breaks in templates. */
345 {
346 tree ctor =
349 complain);
359 {
360 /* This is a class that needs constructing, but doesn't have
361 a user-provided constructor. So we need to zero-initialize
362 the object and then call the implicitly defined ctor.
363 This will be handled in simplify_aggr_init_expr. */
366 }
367 }
369 /* Discard any access checking during subobject initialization;
370 the checks are implied by the call to the ctor which we have
371 verified is OK (cpp0x/defaulted46.C). */
376 }
378 /* Like build_value_init, but don't call the constructor for TYPE. Used
379 for base initializers. */
381 tree
383 {
385 {
389 }
390 /* FIXME the class and array cases should just use digest_init once it is
391 SFINAE-enabled. */
393 {
398 {
399 tree field;
402 /* Iterate over the fields, building initializations. */
404 {
415 /* We could skip vfields and fields of types with
416 user-defined constructors, but I think that won't improve
417 performance at all; it should be simpler in general just
418 to zero out the entire object than try to only zero the
419 bits that actually need it. */
421 /* Note that for class types there will be FIELD_DECLs
422 corresponding to base classes as well. Thus, iterating
423 over TYPE_FIELDs will result in correct initialization of
424 all of the subobjects. */
433 /* We shouldn't have gotten here for anything that would need
434 non-trivial initialization, and gimplify_init_ctor_preeval
435 would need to be fixed to allow it. */
438 }
440 /* Build a constructor to contain the zero- initializations. */
442 }
443 }
445 {
448 /* Iterate over the array elements, building initializations. */
451 /* If we have an error_mark here, we should just return error mark
452 as we don't know the size of the array yet. */
454 {
457 type);
459 }
462 /* A zero-sized array, which is accepted as an extension, will
463 have an upper bound of -1. */
465 {
466 constructor_elt ce;
468 /* If this is a one element array, we just use a regular init. */
471 else
482 /* We shouldn't have gotten here for anything that would need
483 non-trivial initialization, and gimplify_init_ctor_preeval
484 would need to be fixed to allow it. */
487 }
489 /* Build a constructor to contain the initializations. */
491 }
493 {
497 }
499 {
503 }
506 }
508 /* Initialize current class with INIT, a TREE_LIST of
509 arguments for a target constructor. If TREE_LIST is void_type_node,
510 an empty initializer list was given. */
512 static void
514 {
520 tf_warning_or_error));
522 {
524 LOOKUP_NORMAL
525 |LOOKUP_NONVIRTUAL
531 }
532 }
534 /* Return the non-static data initializer for FIELD_DECL MEMBER. */
536 tree
538 {
539 tree init;
544 {
545 /* Use a PLACEHOLDER_EXPR when we don't have a 'this' parameter to
546 refer to; constexpr evaluation knows what to do with it. */
549 }
552 {
557 /* Check recursive instantiation. */
559 {
563 }
564 else
565 {
568 /* Do deferred instantiation of the NSDMI. */
569 init = (tsubst_copy_and_build
576 }
577 }
578 else
579 {
582 {
583 unparsed:
588 }
589 /* Strip redundant TARGET_EXPR so we don't need to remap it, and
590 so the aggregate init code below will see a CONSTRUCTOR. */
596 /* Now put it back so C++17 copy elision works. */
598 }
602 }
604 /* Diagnose the flexible array MEMBER if its INITializer is non-null
605 and return true if so. Otherwise return false. */
607 bool
609 {
617 /* Point at the flexible array member declaration if it's initialized
618 in-class, and at the ctor if it's initialized in a ctor member
619 initializer list. */
620 location_t loc;
622 || !current_function_decl
625 else
630 }
632 /* Initialize MEMBER, a FIELD_DECL, with INIT, a TREE_LIST of
633 arguments. If TREE_LIST is void_type_node, an empty initializer
634 list was given; if NULL_TREE no initializer was given. */
636 static void
638 {
639 tree decl;
642 /* Use the non-static data member initializer if there was no
643 mem-initializer for this field. */
650 /* Effective C++ rule 12 requires that all data members be
651 initialized. */
655 member);
657 /* Get an lvalue for the data member. */
661 tf_warning_or_error);
667 {
669 /* Handle references. */
676 member);
677 }
680 {
681 /* mem() means value-initialization. */
683 {
687 }
688 else
689 {
695 }
696 }
697 /* Deal with this here, as we will get confused if we try to call the
698 assignment op for an anonymous union. This can happen in a
699 synthesized copy constructor. */
701 {
703 {
706 }
707 }
710 /* Pre-digested NSDMI. */
713 /* { } mem-initializer. */
718 {
719 /* With references and list-initialization, we need to deal with
720 extending temporary lifetimes. 12.2p5: "A temporary bound to a
721 reference member in a constructor’s ctor-initializer (12.6.2)
722 persists until the constructor exits." */
727 tf_warning_or_error);
729 {
734 }
737 /* A FIELD_DECL doesn't really have a suitable lifetime, but
738 make_temporary_var_for_ref_to_temp will treat it as automatic and
739 set_up_extended_ref_temp wants to use the decl in a warning. */
749 }
752 {
754 {
756 {
757 /* Check to make sure the member initializer is valid and
758 something like a CONSTRUCTOR in: T a[] = { 1, 2 } and
759 if it isn't, return early to avoid triggering another
760 error below. */
766 else
771 }
775 {
777 {
778 /* Initialize the array only if it's not a flexible
779 array member (i.e., if it has an upper bound). */
783 }
784 }
785 else
787 }
788 else
789 {
796 {
797 /* TYPE_NEEDS_CONSTRUCTING can be set just because we have a
798 vtable; still give this diagnostic. */
803 }
805 tf_warning_or_error));
806 }
807 }
808 else
809 {
811 {
812 tree core_type;
813 /* member traversal: note it leaves init NULL */
815 {
820 }
822 {
827 }
837 }
839 /* There was an explicit member initialization. Do some work
840 in that case. */
842 tf_warning_or_error);
844 /* Reject a member initializer for a flexible array member. */
848 tf_warning_or_error));
849 }
852 {
853 tree expr;
858 tf_warning_or_error);
861 tf_warning_or_error);
866 }
867 }
869 /* Returns a TREE_LIST containing (as the TREE_PURPOSE of each node) all
870 the FIELD_DECLs on the TYPE_FIELDS list for T, in reverse order. */
872 static tree
874 {
875 tree fields;
877 /* Note whether or not T is a union. */
882 {
883 tree fieldtype;
885 /* Skip CONST_DECLs for enumeration constants and so forth. */
891 /* For an anonymous struct or union, we must recursively
892 consider the fields of the anonymous type. They can be
893 directly initialized from the constructor. */
895 {
896 /* Add this field itself. Synthesized copy constructors
897 initialize the entire aggregate. */
899 /* And now add the fields in the anonymous aggregate. */
902 }
903 /* Add this field. */
906 }
909 }
911 /* Return the innermost aggregate scope for FIELD, whether that is
912 the enclosing class or an anonymous aggregate within it. */
914 static tree
916 {
919 else
921 }
923 /* The MEM_INITS are a TREE_LIST. The TREE_PURPOSE of each list gives
924 a FIELD_DECL or BINFO in T that needs initialization. The
925 TREE_VALUE gives the initializer, or list of initializer arguments.
927 Return a TREE_LIST containing all of the initializations required
928 for T, in the order in which they should be performed. The output
929 list has the same format as the input. */
931 static tree
933 {
934 tree init;
936 tree sorted_inits;
937 tree next_subobject;
942 /* Build up a list of initializations. The TREE_PURPOSE of entry
943 will be the subobject (a FIELD_DECL or BINFO) to initialize. The
944 TREE_VALUE will be the constructor arguments, or NULL if no
945 explicit initialization was provided. */
948 /* Process the virtual bases. */
953 /* Process the direct bases. */
959 /* Process the non-static data members. */
961 /* Reverse the entire list of initializations, so that they are in
962 the order that they will actually be performed. */
965 /* If the user presented the initializers in an order different from
966 that in which they will actually occur, we issue a warning. Keep
967 track of the next subobject which can be explicitly initialized
968 without issuing a warning. */
971 /* Go through the explicit initializers, filling in TREE_PURPOSE in
972 the SORTED_INITS. */
974 {
975 tree subobject;
976 tree subobject_init;
980 /* If the explicit initializers are in sorted order, then
981 SUBOBJECT will be NEXT_SUBOBJECT, or something following
982 it. */
984 subobject_init;
989 /* Issue a warning if the explicit initializer order does not
990 match that which will actually occur.
991 ??? Are all these on the correct lines? */
993 {
998 else
1004 else
1008 }
1010 /* Look again, from the beginning of the list. */
1012 {
1016 }
1018 /* It is invalid to initialize the same subobject more than
1019 once. */
1021 {
1025 subobject);
1026 else
1029 subobject);
1030 }
1032 /* Record the initialization. */
1035 }
1037 /* [class.base.init]
1039 If a ctor-initializer specifies more than one mem-initializer for
1040 multiple members of the same union (including members of
1041 anonymous unions), the ctor-initializer is ill-formed.
1043 Here we also splice out uninitialized union members. */
1045 {
1049 {
1050 tree field;
1051 tree ctx;
1057 /* Skip base classes. */
1061 /* If this is an anonymous aggregate with no explicit initializer,
1062 splice it out. */
1066 /* See if this field is a member of a union, or a member of a
1067 structure contained in a union, etc. */
1070 /* If this field is not a member of a union, skip it. */
1075 /* If this union member has no explicit initializer and no NSDMI,
1076 splice it out. */
1079 else
1082 /* It's only an error if we have two initializers for the same
1083 union type. */
1085 {
1088 }
1090 /* See if LAST_FIELD and the field initialized by INIT are
1091 members of the same union (or the union itself). If so, there's
1092 a problem, unless they're actually members of the same structure
1093 which is itself a member of a union. For example, given:
1095 union { struct { int i; int j; }; };
1097 initializing both `i' and `j' makes sense. */
1098 ctx = common_enclosing_class
1104 {
1105 /* A mem-initializer hides an NSDMI. */
1110 else
1111 {
1114 ctx);
1116 }
1117 }
1121 next:
1124 splice:
1127 }
1128 }
1131 }
1133 /* Callback for cp_walk_tree to mark all PARM_DECLs in a tree as read. */
1135 static tree
1137 {
1142 }
1144 /* Initialize all bases and members of CURRENT_CLASS_TYPE. MEM_INITS
1145 is a TREE_LIST giving the explicit mem-initializer-list for the
1146 constructor. The TREE_PURPOSE of each entry is a subobject (a
1147 FIELD_DECL or a BINFO) of the CURRENT_CLASS_TYPE. The TREE_VALUE
1148 is a TREE_LIST giving the arguments to the constructor or
1149 void_type_node for an empty list of arguments. */
1151 void
1153 {
1156 /* We will already have issued an error message about the fact that
1157 the type is incomplete. */
1164 {
1165 /* Delegating constructor. */
1169 }
1175 /* Sort the mem-initializers into the order in which the
1176 initializations should be performed. */
1181 /* Initialize base classes. */
1185 {
1189 /* We already have issued an error message. */
1193 /* Suppress access control when calling the inherited ctor. */
1195 && flag_new_inheriting_ctors
1201 {
1202 /* If these initializations are taking place in a copy constructor,
1203 the base class should probably be explicitly initialized if there
1204 is a user-defined constructor in the base class (other than the
1205 default constructor, which will be called anyway). */
1213 }
1215 /* Initialize the base. */
1217 {
1218 tree base_addr;
1224 tf_warning_or_error),
1225 arguments,
1226 flags,
1227 tf_warning_or_error);
1229 }
1231 /* C++14 DR1658 Means we do not have to construct vbases of
1232 abstract classes. */
1234 else
1235 /* When not constructing vbases of abstract classes, at least mark
1236 the arguments expressions as read to avoid
1237 -Wunused-but-set-parameter false positives. */
1242 }
1245 /* Initialize the vptrs. */
1248 /* Initialize the data members. */
1250 {
1254 }
1255 }
1257 /* Returns the address of the vtable (i.e., the value that should be
1258 assigned to the vptr) for BINFO. */
1260 tree
1262 {
1264 tree vtbl;
1267 /* If this is a virtual primary base, then the vtable we want to store
1268 is that for the base this is being used as the primary base of. We
1269 can't simply skip the initialization, because we may be expanding the
1270 inits of a subobject constructor where the virtual base layout
1271 can be different. */
1275 /* Figure out what vtable BINFO's vtable is based on, and mark it as
1276 used. */
1280 /* Now compute the address to use when initializing the vptr. */
1286 }
1288 /* This code sets up the virtual function tables appropriate for
1289 the pointer DECL. It is a one-ply initialization.
1291 BINFO is the exact type that DECL is supposed to be. In
1292 multiple inheritance, this might mean "C's A" if C : A, B. */
1294 static void
1296 {
1298 tree vtt_index;
1300 /* Compute the initializer for vptr. */
1303 /* We may get this vptr from a VTT, if this is a subobject
1304 constructor or subobject destructor. */
1307 {
1308 tree vtbl2;
1309 tree vtt_parm;
1311 /* Compute the value to use, when there's a VTT. */
1317 /* The actual initializer is the VTT value only in the subobject
1318 constructor. In maybe_clone_body we'll substitute NULL for
1319 the vtt_parm in the case of the non-subobject constructor. */
1321 }
1323 /* Compute the location of the vtpr. */
1325 tf_warning_or_error),
1329 /* Assign the vtable to the vptr. */
1333 }
1335 /* If an exception is thrown in a constructor, those base classes already
1336 constructed must be destroyed. This function creates the cleanup
1337 for BINFO, which has just been constructed. If FLAG is non-NULL,
1338 it is a DECL which is nonzero when this base needs to be
1339 destroyed. */
1341 static void
1343 {
1344 tree expr;
1349 /* Call the destructor. */
1351 base_dtor_identifier,
1352 NULL,
1353 binfo,
1355 tf_warning_or_error);
1367 }
1369 /* Construct the virtual base-class VBASE passing the ARGUMENTS to its
1370 constructor. */
1372 static void
1374 {
1375 tree inner_if_stmt;
1376 tree exp;
1377 tree flag;
1379 /* If there are virtual base classes with destructors, we need to
1380 emit cleanups to destroy them if an exception is thrown during
1381 the construction process. These exception regions (i.e., the
1382 period during which the cleanups must occur) begin from the time
1383 the construction is complete to the end of the function. If we
1384 create a conditional block in which to initialize the
1385 base-classes, then the cleanup region for the virtual base begins
1386 inside a block, and ends outside of that block. This situation
1387 confuses the sjlj exception-handling code. Therefore, we do not
1388 create a single conditional block, but one for each
1389 initialization. (That way the cleanup regions always begin
1390 in the outer block.) We trust the back end to figure out
1391 that the FLAG will not change across initializations, and
1392 avoid doing multiple tests. */
1397 /* Compute the location of the virtual base. If we're
1398 constructing virtual bases, then we must be the most derived
1399 class. Therefore, we don't have to look up the virtual base;
1400 we already know where it is. */
1409 }
1411 /* Find the context in which this FIELD can be initialized. */
1413 static tree
1415 {
1418 /* Anonymous union members can be initialized in the first enclosing
1419 non-anonymous union context. */
1423 }
1425 /* Function to give error message if member initialization specification
1426 is erroneous. FIELD is the member we decided to initialize.
1427 TYPE is the type for which the initialization is being performed.
1428 FIELD must be a member of TYPE.
1430 MEMBER_NAME is the name of the member. */
1432 static int
1434 {
1438 {
1440 member_name);
1442 }
1444 {
1447 field);
1449 }
1451 {
1455 }
1457 {
1459 member_name);
1461 }
1464 }
1466 /* NAME is a FIELD_DECL, an IDENTIFIER_NODE which names a field, or it
1467 is a _TYPE node or TYPE_DECL which names a base for that type.
1468 Check the validity of NAME, and return either the base _TYPE, base
1469 binfo, or the FIELD_DECL of the member. If NAME is invalid, return
1470 NULL_TREE and issue a diagnostic.
1472 An old style unnamed direct single base construction is permitted,
1473 where NAME is NULL. */
1475 tree
1477 {
1478 tree basetype;
1479 tree field;
1485 {
1486 /* This is an obsolete unnamed base class initializer. The
1487 parser will already have warned about its use. */
1489 {
1492 current_class_type);
1495 basetype = BINFO_TYPE
1500 current_class_type);
1502 }
1503 }
1505 {
1508 }
1511 else
1515 {
1516 tree class_binfo;
1517 tree direct_binfo;
1518 tree virtual_binfo;
1529 /* Look for a direct base. */
1534 /* Look for a virtual base -- unless the direct base is itself
1535 virtual. */
1539 /* [class.base.init]
1541 If a mem-initializer-id is ambiguous because it designates
1542 both a direct non-virtual base class and an inherited virtual
1543 base class, the mem-initializer is ill-formed. */
1545 {
1547 basetype);
1549 }
1552 {
1556 else
1560 }
1563 }
1564 else
1565 {
1568 else
1573 }
1576 }
1578 /* This is like `expand_member_init', only it stores one aggregate
1579 value into another.
1581 INIT comes in two flavors: it is either a value which
1582 is to be stored in EXP, or it is a parameter list
1583 to go to a constructor, which will operate on EXP.
1584 If INIT is not a parameter list for a constructor, then set
1585 LOOKUP_ONLYCONVERTING.
1586 If FLAGS is LOOKUP_ONLYCONVERTING then it is the = init form of
1587 the initializer, if FLAGS is 0, then it is the (init) form.
1588 If `init' is a CONSTRUCTOR, then we emit a warning message,
1589 explaining that such initializations are invalid.
1591 If INIT resolves to a CALL_EXPR which happens to return
1592 something of the type we are looking for, then we know
1593 that we can safely use that call to perform the
1594 initialization.
1596 The virtual function table pointer cannot be set up here, because
1597 we do not really know its type.
1599 This never calls operator=().
1601 When initializing, nothing is CONST.
1603 A default copy constructor may have to be used to perform the
1604 initialization.
1606 A constructor or a conversion operator may have to be used to
1607 perform the initialization, but not both, as it would be ambiguous. */
1609 tree
1611 {
1612 tree stmt_expr;
1613 tree compound_stmt;
1623 location_t init_loc = (init
1631 {
1636 {
1640 {
1641 /* Wrap the initializer in a CONSTRUCTOR so that build_vec_init
1642 recognizes it as direct-initialization. */
1646 }
1647 }
1648 else
1649 {
1650 /* An array may not be initialized use the parenthesized
1651 initialization form -- unless the initializer is "()". */
1653 {
1657 }
1658 /* Must arrange to initialize each element of EXP
1659 from elements of INIT. */
1669 {
1673 else
1675 }
1676 }
1680 from_array,
1681 complain);
1685 /* Restore the type of init unless it was used directly. */
1689 }
1700 /* Just know that we've seen something for this node. */
1714 }
1716 static void
1718 tsubst_flags_t complain)
1719 {
1722 /* It fails because there may not be a constructor which takes
1723 its own type as the first (or only parameter), but which does
1724 take other types via a conversion. So, if the thing initializing
1725 the expression is a unit element of type X, first try X(X&),
1726 followed by initialization by X. If neither of these work
1727 out, then look hard. */
1728 tree rval;
1731 /* If we have direct-initialization from an initializer list, pull
1732 it out of the TREE_LIST so the code below can see it. */
1735 {
1739 /* Only call reshape_init if it has not been called earlier
1740 by the callers. */
1743 }
1747 /* A brace-enclosed initializer for an aggregate. In C++0x this can
1748 happen for direct-initialization, too. */
1751 /* A CONSTRUCTOR of the target's type is a previously digested
1752 initializer, whether that happened just above or in
1753 cp_parser_late_parsing_nsdmi.
1755 A TARGET_EXPR with TARGET_EXPR_DIRECT_INIT_P or TARGET_EXPR_LIST_INIT_P
1756 set represents the whole initialization, so we shouldn't build up
1757 another ctor call. */
1764 {
1765 /* Early initialization via a TARGET_EXPR only works for
1766 complete objects. */
1773 }
1777 {
1778 /* Base subobjects should only get direct-initialization. */
1782 /* Do nothing. We hit this in two cases: Reference initialization,
1783 where we aren't initializing a real variable, so we don't want
1784 to run a new constructor; and catching an exception, where we
1785 have already built up the constructor call so we could wrap it
1787 else
1792 /* We need to protect the initialization of a catch parm with a
1793 call to terminate(), which shows up as a MUST_NOT_THROW_EXPR
1794 around the TARGET_EXPR for the copy constructor. See
1795 initialize_handler_parm. */
1796 {
1800 }
1801 else
1806 }
1811 {
1815 }
1816 else
1821 {
1822 /* Delegating constructor. */
1823 tree complete;
1824 tree base;
1827 /* Unshare the arguments for the second call. */
1830 {
1833 }
1836 complain);
1842 complain);
1845 }
1846 else
1847 {
1852 complain);
1853 }
1859 {
1862 {
1866 }
1867 }
1869 /* FIXME put back convert_to_void? */
1872 }
1874 /* This function is responsible for initializing EXP with INIT
1875 (if any).
1877 BINFO is the binfo of the type for who we are performing the
1878 initialization. For example, if W is a virtual base class of A and B,
1879 and C : A, B.
1880 If we are initializing B, then W must contain B's W vtable, whereas
1881 were we initializing C, W must contain C's W vtable.
1883 TRUE_EXP is nonzero if it is the true expression being initialized.
1884 In this case, it may be EXP, or may just contain EXP. The reason we
1885 need this is because if EXP is a base element of TRUE_EXP, we
1886 don't necessarily know by looking at EXP where its virtual
1887 baseclass fields should really be pointing. But we do know
1888 from TRUE_EXP. In constructors, we don't know anything about
1889 the value being initialized.
1891 FLAGS is just passed to `build_new_method_call'. See that function
1892 for its description. */
1894 static void
1896 tsubst_flags_t complain)
1897 {
1903 /* Use a function returning the desired type to initialize EXP for us.
1904 If the function is a constructor, and its first argument is
1905 NULL_TREE, know that it was meant for us--just slide exp on
1906 in and expand the constructor. Constructors now come
1907 as TARGET_EXPRs. */
1911 {
1913 /* If store_init_value returns NULL_TREE, the INIT has been
1914 recorded as the DECL_INITIAL for EXP. That means there's
1915 nothing more we have to do. */
1921 }
1923 /* List-initialization from {} becomes value-initialization for non-aggregate
1924 classes with default constructors. Handle this here when we're
1925 initializing a base, so protected access works. */
1927 {
1934 }
1936 /* If an explicit -- but empty -- initializer list was present,
1937 that's value-initialization. */
1939 {
1940 /* If the type has data but no user-provided ctor, we need to zero
1941 out the object. */
1944 {
1947 /* Don't clobber already initialized virtual bases. */
1950 field_size);
1953 }
1955 /* If we don't need to mess with the constructor at all,
1956 then we're done. */
1960 /* Otherwise fall through and call the constructor. */
1962 }
1964 /* We know that expand_default_init can handle everything we want
1965 at this point. */
1967 }
1969 /* Report an error if TYPE is not a user-defined, class type. If
1970 OR_ELSE is nonzero, give an error message. */
1972 int
1974 {
1979 {
1983 }
1985 }
1987 tree
1989 {
1995 else
1997 }
1999 /* Build a reference to a member of an aggregate. This is not a C++
2000 `&', but really something which can have its address taken, and
2001 then act as a pointer to member, for example TYPE :: FIELD can have
2002 its address taken by saying & TYPE :: FIELD. ADDRESS_P is true if
2003 this expression is the operand of "&".
2005 @@ Prints out lousy diagnostics for operator <typename>
2006 @@ fields.
2008 @@ This function should be rewritten and placed in search.c. */
2010 tree
2012 tsubst_flags_t complain)
2013 {
2014 tree decl;
2017 /* class templates can come in as TEMPLATE_DECLs here. */
2030 /* Callers should call mark_used before this point. */
2035 {
2039 }
2041 /* Entities other than non-static members need no further
2042 processing. */
2049 {
2053 }
2055 /* Set up BASEBINFO for member lookup. */
2058 /* A lot of this logic is now handled in lookup_member. */
2060 {
2061 /* Go from the TREE_BASELINK to the member function info. */
2065 {
2066 /* Get rid of a potential OVERLOAD around it. */
2069 /* Unique functions are handled easily. */
2071 /* For non-static member of base class, we need a special rule
2072 for access checking [class.protected]:
2074 If the access is to form a pointer to member, the
2075 nested-name-specifier shall name the derived class
2076 (or any class derived from that class). */
2081 complain);
2082 else
2084 complain);
2090 }
2091 else
2093 }
2095 {
2096 /* We need additional test besides the one in
2097 check_accessibility_of_qualified_id in case it is
2098 a pointer to non-static member. */
2100 complain))
2102 }
2105 {
2106 /* If MEMBER is non-static, then the program has fallen afoul of
2107 [expr.prim]:
2109 An id-expression that denotes a nonstatic data member or
2110 nonstatic member function of a class can only be used:
2112 -- as part of a class member access (_expr.ref_) in which the
2113 object-expression refers to the member's class or a class
2114 derived from that class, or
2116 -- to form a pointer to member (_expr.unary.op_), or
2118 -- in the body of a nonstatic member function of that class or
2119 of a class derived from that class (_class.mfct.nonstatic_), or
2121 -- in a mem-initializer for a constructor for that class or for
2122 a class derived from that class (_class.base.init_). */
2124 {
2125 /* Build a representation of the qualified name suitable
2126 for use as the operand to "&" -- even though the "&" is
2127 not actually present. */
2129 /* In Microsoft mode, treat a non-static member function as if
2130 it were a pointer-to-member. */
2132 {
2135 }
2140 }
2142 {
2146 }
2148 }
2153 }
2155 /* If DECL is a scalar enumeration constant or variable with a
2156 constant initializer, return the initializer (or, its initializers,
2157 recursively); otherwise, return DECL. If STRICT_P, the
2158 initializer is only returned if DECL is a
2159 constant-expression. If RETURN_AGGREGATE_CST_OK_P, it is ok to
2160 return an aggregate constant. */
2162 static tree
2164 {
2169 {
2170 tree init;
2171 /* If DECL is a static data member in a template
2172 specialization, we must instantiate it here. The
2173 initializer for the static data member is not processed
2174 until needed; we need it now. */
2179 {
2182 /* Treat the error as a constant to avoid cascading errors on
2183 excessively recursive template instantiation (c++/9335). */
2185 else
2187 }
2188 /* Initializers in templates are generally expanded during
2189 instantiation, so before that for const int i(2)
2190 INIT is a TREE_LIST with the actual initializer as
2191 TREE_VALUE. */
2193 && init
2197 /* Instantiate a non-dependent initializer for user variables. We
2198 mustn't do this for the temporary for an array compound literal;
2199 trying to instatiate the initializer will keep creating new
2200 temporaries until we crash. Probably it's not useful to do it for
2201 other artificial variables, either. */
2207 || (!return_aggregate_cst_ok_p
2208 /* Unless RETURN_AGGREGATE_CST_OK_P is true, do not
2209 return an aggregate constant (of which string
2210 literals are a special case), as we do not want
2211 to make inadvertent copies of such entities, and
2212 we must be sure that their addresses are the
2213 same everywhere. */
2217 /* Don't return a CONSTRUCTOR for a variable with partial run-time
2218 initialization, since it doesn't represent the entire value. */
2222 /* If the variable has a dynamic initializer, don't use its
2223 DECL_INITIAL which doesn't reflect the real value. */
2230 }
2232 }
2234 /* If DECL is a CONST_DECL, or a constant VAR_DECL initialized by constant
2235 of integral or enumeration type, or a constexpr variable of scalar type,
2236 then return that value. These are those variables permitted in constant
2237 expressions by [5.19/1]. */
2239 tree
2241 {
2244 }
2246 /* Like scalar_constant_value, but can also return aggregate initializers. */
2248 tree
2250 {
2253 }
2255 /* A more relaxed version of scalar_constant_value, used by the
2256 common C/C++ code. */
2258 tree
2260 {
2263 }
2264 \f
2265 /* Common subroutines of build_new and build_vec_delete. */
2266 \f
2267 /* Build and return a NEW_EXPR. If NELTS is non-NULL, TYPE[NELTS] is
2268 the type of the object being allocated; otherwise, it's just TYPE.
2269 INIT is the initializer, if any. USE_GLOBAL_NEW is true if the
2270 user explicitly wrote "::operator new". PLACEMENT, if non-NULL, is
2271 a vector of arguments to be provided as arguments to a placement
2272 new operator. This routine performs no semantic checks; it just
2273 creates and returns a NEW_EXPR. */
2275 static tree
2278 {
2279 tree init_list;
2280 tree new_expr;
2282 /* If INIT is NULL, the we want to store NULL_TREE in the NEW_EXPR.
2283 If INIT is not NULL, then we want to store VOID_ZERO_NODE. This
2284 permits us to distinguish the case of a missing initializer "new
2285 int" from an empty initializer "new int()". */
2290 else
2295 init_list);
2300 }
2302 /* Diagnose uninitialized const members or reference members of type
2303 TYPE. USING_NEW is used to disambiguate the diagnostic between a
2304 new expression without a new-initializer and a declaration. Returns
2305 the error count. */
2307 static int
2310 {
2311 tree field;
2318 {
2319 tree field_type;
2330 {
2333 {
2335 {
2339 else
2341 }
2342 else
2343 {
2348 else
2351 }
2354 }
2355 }
2358 {
2361 {
2363 {
2367 else
2369 }
2370 else
2371 {
2376 else
2379 }
2382 }
2383 }
2386 error_count
2389 }
2391 }
2393 int
2395 {
2397 }
2399 /* Call __cxa_bad_array_new_length to indicate that the size calculation
2400 overflowed. Pretend it returns sizetype so that it plays nicely in the
2401 COND_EXPR. */
2403 tree
2405 {
2407 {
2412 fn = push_throw_library_fn
2414 }
2417 }
2419 /* Attempt to find the initializer for field T in the initializer INIT,
2420 when non-null. Returns the initializer when successful and NULL
2421 otherwise. */
2422 static tree
2424 {
2431 /* Iterate over all top-level initializer elements. */
2433 {
2434 /* If the member T is found, return it. */
2438 /* Otherwise continue and/or recurse into nested initializers. */
2442 }
2444 }
2446 /* Attempt to verify that the argument, OPER, of a placement new expression
2447 refers to an object sufficiently large for an object of TYPE or an array
2448 of NELTS of such objects when NELTS is non-null, and issue a warning when
2449 it does not. SIZE specifies the size needed to construct the object or
2450 array and captures the result of NELTS * sizeof (TYPE). (SIZE could be
2451 greater when the array under construction requires a cookie to store
2452 NELTS. GCC's placement new expression stores the cookie when invoking
2453 a user-defined placement new operator function but not the default one.
2454 Placement new expressions with user-defined placement new operator are
2455 not diagnosed since we don't know how they use the buffer (this could
2456 be a future extension). */
2457 static void
2459 {
2462 /* The number of bytes to add to or subtract from the size of the provided
2463 buffer based on an offset into an array or an array element reference.
2464 Although intermediate results may be negative (as in a[3] - 2) the final
2465 result cannot be. */
2467 /* True when the size of the entire destination object should be used
2468 to compute the possibly optimistic estimate of the available space. */
2470 /* True when the reference to the destination buffer is an ADDR_EXPR. */
2475 /* Using a function argument or a (non-array) variable as an argument
2476 to placement new is not checked since it's unknown what it might
2477 point to. */
2483 /* Evaluate any constant expressions. */
2486 /* Handle the common case of array + offset expression when the offset
2487 is a constant. */
2489 {
2490 /* If the offset is comple-time constant, use it to compute a more
2491 accurate estimate of the size of the buffer. Since the operand
2492 of POINTER_PLUS_EXPR is represented as an unsigned type, convert
2493 it to signed first.
2494 Otherwise, use the size of the entire array as an optimistic
2495 estimate (this may lead to false negatives). */
2499 else
2505 }
2510 {
2513 }
2519 {
2520 /* Similar to the offset computed above, see if the array index
2521 is a compile-time constant. If so, and unless the offset was
2522 not a compile-time constant, use the index to determine the
2523 size of the buffer. Otherwise, use the entire array as
2524 an optimistic estimate of the size. */
2528 else
2529 {
2532 }
2535 }
2537 /* Refers to the declared object that constains the subobject referenced
2538 by OPER. When the object is initialized, makes it possible to determine
2539 the actual size of a flexible array member used as the buffer passed
2540 as OPER to placement new. */
2542 /* True when operand is a COMPONENT_REF, to distinguish flexible array
2543 members from arrays of unspecified size. */
2546 /* Descend into a struct or union to find the member whose address
2547 is being used as the argument. */
2549 {
2555 }
2561 {
2562 /* A possibly optimistic estimate of the number of bytes available
2563 in the destination buffer. */
2565 /* True when the estimate above is in fact the exact size
2566 of the destination buffer rather than an estimate. */
2569 /* Treat members of unions and members of structs uniformly, even
2570 though the size of a member of a union may be viewed as extending
2571 to the end of the union itself (it is by __builtin_object_size). */
2575 {
2576 /* Use the size of the entire array object when the expression
2577 refers to a variable or its size depends on an expression
2578 that's not a compile-time constant. */
2581 }
2584 {
2585 /* Use the size of the type of the destination buffer object
2586 as the optimistic estimate of the available space in it. */
2588 }
2590 {
2591 /* Constructing into a buffer provided by the flexible array
2592 member of a declared object (which is permitted as a G++
2593 extension). If the array member has been initialized,
2594 determine its size from the initializer. Otherwise,
2595 the array size is zero. */
2600 }
2601 else
2602 {
2603 /* Bail if neither the size of the object nor its type is known. */
2605 }
2610 {
2611 /* Avoid diagnosing flexible array members (which are accepted
2612 as an extension and diagnosed with -Wpedantic) and zero-length
2613 arrays (also an extension).
2614 Overflowing construction in one-element arrays is diagnosed
2615 only at level 2. */
2623 && !var_decl
2626 }
2628 /* The size of the buffer can only be adjusted down but not up. */
2631 /* Reduce the size of the buffer by the adjustment computed above
2632 from the offset and/or the index into the array. */
2635 else
2638 /* The minimum amount of space needed for the allocation. This
2639 is an optimistic estimate that makes it possible to detect
2640 placement new invocation for some undersize buffers but not
2641 others. */
2651 else
2652 {
2653 /* The type is a VLA. */
2655 }
2658 {
2662 exact_size ?
2663 "placement new constructing an object of type "
2664 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2665 "and size %qwi"
2667 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2671 bytes_avail);
2672 else
2674 exact_size ?
2675 "placement new constructing an array of objects "
2676 "of type %qT and size %qwu in a region of type %qT "
2677 "and size %qwi"
2679 "of type %qT and size %qwu in a region of type %qT "
2682 bytes_avail);
2683 else
2685 exact_size ?
2686 "placement new constructing an object of type %qT "
2687 "and size %qwu in a region of type %qT and size %qwi"
2689 "and size %qwu in a region of type %qT and size "
2692 bytes_avail);
2693 }
2694 }
2695 }
2697 /* True if alignof(T) > __STDCPP_DEFAULT_NEW_ALIGNMENT__. */
2699 bool
2701 {
2704 }
2706 /* Return the alignment we expect malloc to guarantee. This should just be
2707 MALLOC_ABI_ALIGNMENT, but that macro defaults to only BITS_PER_WORD for some
2708 reason, so don't let the threshold be smaller than max_align_t_align. */
2710 unsigned
2712 {
2714 }
2716 /* Determine whether an allocation function is a namespace-scope
2717 non-replaceable placement new function. See DR 1748.
2718 TODO: Enable in all standard modes. */
2719 static bool
2721 {
2723 {
2728 }
2730 }
2732 /* Generate code for a new-expression, including calling the "operator
2733 new" function, initializing the object, and, if an exception occurs
2734 during construction, cleaning up. The arguments are as for
2735 build_raw_new_expr. This may change PLACEMENT and INIT.
2736 TYPE is the type of the object being constructed, possibly an array
2737 of NELTS elements when NELTS is non-null (in "new T[NELTS]", T may
2738 be an array of the form U[inner], with the whole expression being
2739 "new U[NELTS][inner]"). */
2741 static tree
2744 tsubst_flags_t complain)
2745 {
2747 /* True iff this is a call to "operator new[]" instead of just
2748 "operator new". */
2750 /* If ARRAY_P is true, the element type of the array. This is never
2751 an ARRAY_TYPE; for something like "new int[3][4]", the
2752 ELT_TYPE is "int". If ARRAY_P is false, this is the same type as
2753 TYPE. */
2754 tree elt_type;
2755 /* The type of the new-expression. (This type is always a pointer
2756 type.) */
2757 tree pointer_type;
2758 tree non_const_pointer_type;
2759 /* The most significant array bound in int[OUTER_NELTS][inner]. */
2761 /* For arrays with a non-constant number of elements, a bounds checks
2762 on the NELTS parameter to avoid integer overflow at runtime. */
2765 /* Number of the "inner" elements in "new T[OUTER_NELTS][inner]". */
2768 /* Size of the inner array elements (those with constant dimensions). */
2769 offset_int inner_size;
2770 /* The address returned by the call to "operator new". This node is
2771 a VAR_DECL and is therefore reusable. */
2772 tree alloc_node;
2773 tree alloc_fn;
2776 /* If non-NULL, the number of extra bytes to allocate at the
2777 beginning of the storage allocated for an array-new expression in
2778 order to store the number of elements. */
2780 tree placement_first;
2782 /* True if the function we are calling is a placement allocation
2783 function. */
2785 /* True if the storage must be initialized, either by a constructor
2786 or due to an explicit new-initializer. */
2788 /* The address of the thing allocated, not including any cookie. In
2789 particular, if an array cookie is in use, DATA_ADDR is the
2790 address of the first array element. This node is a VAR_DECL, and
2791 is therefore reusable. */
2792 tree data_addr;
2797 {
2800 }
2802 {
2803 /* Transforms new (T[N]) to new T[N]. The former is a GNU
2804 extension for variable N. (This also covers new T where T is
2805 a VLA typedef.) */
2811 }
2813 /* Lots of logic below. depends on whether we have a constant number of
2814 elements, so go ahead and fold it now. */
2818 /* If our base type is an array, then make sure we know how many elements
2819 it has. */
2823 {
2827 {
2832 {
2836 }
2838 }
2839 else
2840 {
2842 {
2846 }
2848 }
2852 inner_nelts_cst,
2853 complain);
2854 }
2857 {
2860 }
2865 /* Warn if we performed the (T[N]) to T[N] transformation and N is
2866 variable. */
2869 {
2871 {
2878 }
2879 else
2881 }
2884 {
2888 }
2896 {
2898 /* A program that calls for default-initialization [...] of an
2899 entity of reference type is ill-formed. */
2903 /* A new-expression that creates an object of type T initializes
2904 that object as follows:
2905 - If the new-initializer is omitted:
2906 -- If T is a (possibly cv-qualified) non-POD class type
2907 (or array thereof), the object is default-initialized (8.5).
2908 [...]
2909 -- Otherwise, the object created has indeterminate
2910 value. If T is a const-qualified type, or a (possibly
2911 cv-qualified) POD class type (or array thereof)
2912 containing (directly or indirectly) a member of
2913 const-qualified type, the program is ill-formed; */
2923 }
2927 {
2931 }
2935 {
2936 /* Maximum available size in bytes. Half of the address space
2937 minus the cookie size. */
2938 offset_int max_size
2940 /* Maximum number of outer elements which can be allocated. */
2941 offset_int max_outer_nelts;
2942 tree max_outer_nelts_tree;
2948 /* Unconditionally subtract the cookie size. This decreases the
2949 maximum object size and is safe even if we choose not to use
2950 a cookie after all. */
2956 {
2960 }
2968 {
2970 {
2971 /* When the array size is constant, check it at compile time
2972 to make sure it doesn't exceed the implementation-defined
2973 maximum, as required by C++ 14 (in C++ 11 this requirement
2974 isn't explicitly stated but it's enforced anyway -- see
2975 grokdeclarator in cp/decl.c). */
2979 }
2980 }
2981 else
2982 {
2983 /* When a runtime check is necessary because the array size
2984 isn't constant, keep only the top-most seven bits (starting
2985 with the most significant non-zero bit) of the maximum size
2986 to compare the array size against, to simplify encoding the
2987 constant maximum size in the instruction stream. */
2994 outer_nelts,
2995 max_outer_nelts_tree);
2996 }
2997 }
3005 /* If PLACEMENT is a single simple pointer type not passed by
3006 reference, prepare to capture it in a temporary variable. Do
3007 this now, since PLACEMENT will change in the calls below. */
3015 /* Allocate the object. */
3016 tree fnname;
3017 tree fns;
3021 member_new_p = !globally_qualified_p
3023 && (array_p
3028 {
3029 /* Use a class-specific operator new. */
3030 /* If a cookie is required, add some extra space. */
3033 else
3034 {
3036 /* No size arithmetic necessary, so the size check is
3037 not needed. */
3040 }
3041 /* Perform the overflow check. */
3048 /* Create the argument list. */
3050 /* Do name-lookup to find the appropriate operator. */
3053 {
3057 }
3059 {
3061 {
3064 }
3066 }
3070 {
3073 alloc_call
3077 /* If no matching function is found and the allocated object type
3078 has new-extended alignment, the alignment argument is removed
3079 from the argument list, and overload resolution is performed
3080 again. */
3083 }
3087 LOOKUP_NORMAL,
3089 }
3090 else
3091 {
3092 /* Use a global operator new. */
3093 /* See if a cookie might be required. */
3095 {
3097 /* No size arithmetic necessary, so the size check is
3098 not needed. */
3101 }
3107 }
3114 /* Now, check to see if this function is actually a placement
3115 allocation function. This can happen even when PLACEMENT is NULL
3116 because we might have something like:
3118 struct S { void* operator new (size_t, int i = 0); };
3120 A call to `new S' will get this allocation function, even though
3121 there is no explicit placement argument. If there is more than
3122 one argument, or there are variable arguments, then this is a
3123 placement allocation function. */
3124 placement_allocation_fn_p
3129 && !placement_allocation_fn_p
3134 {
3137 {
3143 }
3144 }
3146 /* If we found a simple case of PLACEMENT_EXPR above, then copy it
3147 into a temporary variable. */
3153 {
3159 {
3163 }
3167 {
3168 /* Attempt to make the warning point at the operator new argument. */
3173 }
3174 }
3176 /* In the simple case, we can stop now. */
3181 /* Store the result of the allocation call in a variable so that we can
3182 use it more than once. */
3186 /* Strip any COMPOUND_EXPRs from ALLOC_CALL. */
3190 /* Preevaluate the placement args so that we don't reevaluate them for a
3191 placement delete. */
3193 {
3194 tree inits;
3198 alloc_expr);
3199 }
3201 /* unless an allocation function is declared with an empty excep-
3202 tion-specification (_except.spec_), throw(), it indicates failure to
3203 allocate storage by throwing a bad_alloc exception (clause _except_,
3204 _lib.bad.alloc_); it returns a non-null pointer otherwise If the allo-
3205 cation function is declared with an empty exception-specification,
3206 throw(), it returns null to indicate failure to allocate storage and a
3207 non-null pointer otherwise.
3209 So check for a null exception spec on the op new we just called. */
3212 check_new
3216 {
3217 tree cookie;
3218 tree cookie_ptr;
3219 tree size_ptr_type;
3221 /* Adjust so we're pointing to the start of the object. */
3224 /* Store the number of bytes allocated so that we can know how
3225 many elements to destroy later. We use the last sizeof
3226 (size_t) bytes to store the number of elements. */
3237 {
3238 /* Also store the element size. */
3249 }
3250 }
3251 else
3252 {
3255 }
3257 /* Now use a pointer to the type we've actually allocated. */
3259 /* But we want to operate on a non-const version to start with,
3260 since we'll be modifying the elements. */
3261 non_const_pointer_type = build_pointer_type
3265 /* Any further uses of alloc_node will want this type, too. */
3268 /* Now initialize the allocated object. Note that we preevaluate the
3269 initialization expression, apart from the actual constructor call or
3270 assignment--we do this because we want to delay the allocation as long
3271 as possible in order to minimize the size of the exception region for
3272 placement delete. */
3274 {
3279 {
3282 }
3285 {
3286 /* build_value_init doesn't work in templates, and we don't need
3287 the initializer anyway since we're going to throw it away and
3288 rebuild it at instantiation time, so just build up a single
3289 constructor call to get any appropriate diagnostics. */
3293 complete_ctor_identifier,
3295 LOOKUP_NORMAL,
3296 complain);
3298 }
3300 {
3304 {
3308 else
3309 {
3313 complain);
3314 else
3315 /* We'll check the length at runtime. */
3319 }
3320 }
3322 {
3326 else
3329 }
3330 init_expr
3334 integer_one_node,
3335 complain),
3336 vecinit,
3337 explicit_value_init_p,
3339 complain);
3341 /* An array initialization is stable because the initialization
3342 of each element is a full-expression, so the temporaries don't
3343 leak out. */
3345 }
3346 else
3347 {
3351 {
3353 complete_ctor_identifier,
3355 LOOKUP_NORMAL,
3356 complain);
3357 }
3359 {
3360 /* Something like `new int()'. NO_CLEANUP is needed so
3361 we don't try and build a (possibly ill-formed)
3362 destructor. */
3367 }
3368 else
3369 {
3370 tree ie;
3372 /* We are processing something like `new int (10)', which
3373 means allocate an int, and initialize it with 10. */
3376 complain);
3379 }
3380 /* If the initializer uses C++14 aggregate NSDMI that refer to the
3381 object being initialized, replace them now and don't try to
3382 preevaluate. */
3390 stable = (!had_placeholder
3392 }
3397 /* If any part of the object initialization terminates by throwing an
3398 exception and a suitable deallocation function can be found, the
3399 deallocation function is called to free the memory in which the
3400 object was being constructed, after which the exception continues
3401 to propagate in the context of the new-expression. If no
3402 unambiguous matching deallocation function can be found,
3403 propagating the exception does not cause the object's memory to be
3404 freed. */
3406 {
3408 tree cleanup;
3410 /* The Standard is unclear here, but the right thing to do
3411 is to use the same method for finding deallocation
3412 functions that we use for finding allocation functions. */
3413 cleanup = (build_op_delete_call
3415 alloc_node,
3416 size,
3417 globally_qualified_p,
3419 alloc_fn,
3420 complain));
3425 /* This is much simpler if we were able to preevaluate all of
3426 the arguments to the constructor call. */
3427 {
3428 /* CLEANUP is compiler-generated, so no diagnostics. */
3432 /* Likewise, this try-catch is compiler-generated. */
3434 }
3435 else
3436 /* Ack! First we allocate the memory. Then we set our sentry
3437 variable to true, and expand a cleanup that deletes the
3438 memory if sentry is true. Then we run the constructor, and
3439 finally clear the sentry.
3441 We need to do this because we allocate the space first, so
3442 if there are any temporaries with cleanups in the
3443 constructor args and we weren't able to preevaluate them, we
3444 need this EH region to extend until end of full-expression
3445 to preserve nesting. */
3446 {
3454 /* CLEANUP is compiler-generated, so no diagnostics. */
3464 init_expr
3467 end));
3468 /* Likewise, this is compiler-generated. */
3470 }
3471 }
3472 }
3473 else
3476 /* Now build up the return value in reverse order. */
3486 /* If we don't have an initializer or a cookie, strip the TARGET_EXPR
3487 and return the call (which doesn't need to be adjusted). */
3489 else
3490 {
3492 {
3495 nullptr_node,
3496 complain);
3499 }
3501 /* Perform the allocation before anything else, so that ALLOC_NODE
3502 has been initialized before we start using it. */
3504 }
3509 /* A new-expression is never an lvalue. */
3513 }
3515 /* Generate a representation for a C++ "new" expression. *PLACEMENT
3516 is a vector of placement-new arguments (or NULL if none). If NELTS
3517 is NULL, TYPE is the type of the storage to be allocated. If NELTS
3518 is not NULL, then this is an array-new allocation; TYPE is the type
3519 of the elements in the array and NELTS is the number of elements in
3520 the array. *INIT, if non-NULL, is the initializer for the new
3521 object, or an empty vector to indicate an initializer of "()". If
3522 USE_GLOBAL_NEW is true, then the user explicitly wrote "::new"
3523 rather than just "new". This may change PLACEMENT and INIT. */
3525 tree
3528 {
3529 tree rval;
3538 /* Don't do auto deduction where it might affect mangling. */
3540 {
3543 {
3546 {
3549 }
3551 }
3552 }
3555 {
3562 use_global_new);
3567 {
3569 /* Also copy any CONSTRUCTORs in *init, since reshape_init and
3570 digest_init clobber them in place. */
3572 {
3576 }
3577 }
3583 }
3586 {
3588 {
3591 else
3593 }
3595 /* Try to determine the constant value only for the purposes
3596 of the diagnostic below but continue to use the original
3597 value and handle const folding later. */
3600 /* The expression in a noptr-new-declarator is erroneous if it's of
3601 non-class type and its value before converting to std::size_t is
3602 less than zero. ... If the expression is a constant expression,
3603 the program is ill-fomed. */
3606 {
3610 }
3614 }
3616 /* ``A reference cannot be created by the new operator. A reference
3617 is not an object (8.2.2, 8.4.3), so a pointer to it could not be
3618 returned by new.'' ARM 5.3.3 */
3620 {
3623 else
3626 }
3629 {
3633 }
3635 /* The type allocated must be complete. If the new-type-id was
3636 "T[N]" then we are just checking that "T" is complete here, but
3637 that is equivalent, since the value of "N" doesn't matter. */
3646 {
3652 }
3654 /* Wrap it in a NOP_EXPR so warn_if_unused_value doesn't complain. */
3659 }
3660 \f
3661 static tree
3663 special_function_kind auto_delete_vec,
3665 {
3666 tree virtual_size;
3668 tree size_exp;
3670 /* Temporary variables used by the loop. */
3673 /* This is the body of the loop that implements the deletion of a
3674 single element, and moves temp variables to next elements. */
3675 tree body;
3677 /* This is the LOOP_EXPR that governs the deletion of the elements. */
3680 /* This is the thing that governs what to do after the loop has run. */
3683 /* This is the BIND_EXPR which holds the outermost iterator of the
3684 loop. It is convenient to set this variable up and test it before
3685 executing any other code in the loop.
3686 This is also the containing expression returned by this function. */
3688 tree tmp;
3690 /* We should only have 1-D arrays here. */
3697 {
3700 "possible problem detected in invocation of "
3702 {
3705 "class-specific operator delete [] will be called, "
3707 }
3708 /* This size won't actually be used. */
3711 }
3718 {
3719 /* Make sure the destructor is callable. */
3721 {
3724 complain);
3727 }
3729 }
3731 /* The below is short by the cookie size. */
3736 tbase_init
3740 base),
3741 virtual_size),
3742 complain);
3760 complain);
3768 no_destructor:
3769 /* Delete the storage if appropriate. */
3771 {
3772 tree base_tbd;
3774 /* The below is short by the cookie size. */
3779 /* no header */
3781 else
3782 {
3783 tree cookie_size;
3787 MINUS_EXPR,
3790 cookie_size,
3791 complain);
3795 /* True size with header. */
3797 }
3804 complain);
3805 }
3809 ;
3812 else
3813 /* The delete operator mist be called, even if a destructor
3814 throws. */
3820 /* Outermost wrapper: If pointer is null, punt. */
3823 /* This is a compiler generated comparison, don't emit
3824 e.g. -Wnonnull-compare warning for it. */
3832 {
3835 }
3838 /* Pre-evaluate the SAVE_EXPR outside of the BIND_EXPR. */
3842 }
3844 /* Create an unnamed variable of the indicated TYPE. */
3846 tree
3848 {
3849 tree decl;
3859 }
3861 /* Create a new temporary variable of the indicated TYPE, initialized
3862 to INIT.
3864 It is not entered into current_binding_level, because that breaks
3865 things when it comes time to do final cleanups (which take place
3866 "outside" the binding contour of the function). */
3868 tree
3870 {
3871 tree decl;
3880 }
3882 /* Subroutine of build_vec_init. Returns true if assigning to an array of
3883 INNER_ELT_TYPE from INIT is trivial. */
3885 static bool
3887 {
3892 }
3894 /* Subroutine of build_vec_init: Check that the array has at least N
3895 elements. Other parameters are local variables in build_vec_init. */
3897 void
3899 {
3902 {
3904 {
3906 nelts);
3910 }
3911 /* Don't check an array new when -fno-exceptions. */
3912 }
3914 {
3915 /* Make sure the last element of the initializer is in bounds. */
3916 finish_expr_stmt
3917 (ubsan_instrument_bounds
3919 }
3920 }
3922 /* `build_vec_init' returns tree structure that performs
3923 initialization of a vector of aggregate types.
3925 BASE is a reference to the vector, of ARRAY_TYPE, or a pointer
3926 to the first element, of POINTER_TYPE.
3927 MAXINDEX is the maximum index of the array (one less than the
3928 number of elements). It is only used if BASE is a pointer or
3929 TYPE_DOMAIN (TREE_TYPE (BASE)) == NULL_TREE.
3931 INIT is the (possibly NULL) initializer.
3933 If EXPLICIT_VALUE_INIT_P is true, then INIT must be NULL. All
3934 elements in the array are value-initialized.
3936 FROM_ARRAY is 0 if we should init everything with INIT
3937 (i.e., every element initialized from INIT).
3938 FROM_ARRAY is 1 if we should index into INIT in parallel
3939 with initialization of DECL.
3940 FROM_ARRAY is 2 if we should index into INIT in parallel,
3941 but use assignment instead of initialization. */
3943 tree
3947 {
3948 tree rval;
3951 tree iterator;
3952 /* The type of BASE. */
3954 /* The type of an element in the array. */
3956 /* The element type reached after removing all outer array
3957 types. */
3958 tree inner_elt_type;
3959 /* The type of a pointer to an element in the array. */
3960 tree ptype;
3961 tree stmt_expr;
3962 tree compound_stmt;
3985 /* Look through the TARGET_EXPR around a compound literal. */
3994 {
3997 {
4000 }
4001 }
4003 /* If we have a braced-init-list or string constant, make sure that the array
4004 is big enough for all the initializers. */
4019 || (same_type_ignoring_top_level_qualifiers_p
4021 /* Don't do this if the CONSTRUCTOR might contain something
4022 that might throw and require us to clean up. */
4026 {
4027 /* Do non-default initialization of trivial arrays resulting from
4028 brace-enclosed initializers. In this case, digest_init and
4029 store_constructor will handle the semantics for us. */
4035 }
4041 {
4047 }
4048 else
4051 /* The code we are generating looks like:
4052 ({
4053 T* t1 = (T*) base;
4054 T* rval = t1;
4055 ptrdiff_t iterator = maxindex;
4056 try {
4057 for (; iterator != -1; --iterator) {
4058 ... initialize *t1 ...
4059 ++t1;
4060 }
4061 } catch (...) {
4062 ... destroy elements that were constructed ...
4063 }
4064 rval;
4065 })
4067 We can omit the try and catch blocks if we know that the
4068 initialization will never throw an exception, or if the array
4069 elements do not have destructors. We can omit the loop completely if
4070 the elements of the array do not have constructors.
4072 We actually wrap the entire body of the above in a STMT_EXPR, for
4073 tidiness.
4075 When copying from array to another, when the array elements have
4076 only trivial copy constructors, we should use __builtin_memcpy
4077 rather than generating a loop. That way, we could take advantage
4078 of whatever cleverness the back end has for dealing with copies
4079 of blocks of memory. */
4088 /* If initializing one array from another, initialize element by
4089 element. We rely upon the below calls to do the argument
4090 checking. Evaluate the initializer before entering the try block. */
4092 {
4101 }
4103 /* Protect the entire array initialization so that we can destroy
4104 the partially constructed array if an exception is thrown.
4105 But don't do this if we're assigning. */
4108 {
4110 }
4112 /* Should we try to create a constant initializer? */
4116 : (type_has_constexpr_default_constructor
4122 /* If we're initializing a static array, we want to do static
4123 initialization of any elements with constant initializers even if
4124 some are non-constant. */
4130 /* Skip over the handling of non-empty init lists. */
4133 /* Maybe pull out constant value when from_array? */
4136 {
4137 /* Do non-default initialization of non-trivial arrays resulting from
4138 brace-enclosed initializers. */
4141 /* If the constructor already has the array type, it's been through
4142 digest_init, so we shouldn't try to do anything more. */
4153 {
4155 tree one_init;
4157 num_initialized_elts++;
4164 else
4170 {
4173 {
4177 else
4179 }
4180 else
4181 {
4183 {
4188 }
4190 }
4191 }
4198 complain);
4201 else
4205 complain);
4208 else
4210 }
4212 /* Any elements without explicit initializers get T{}. */
4214 }
4216 {
4217 /* Check that the array is at least as long as the string. */
4224 /* Copy the string to the first part of the array. */
4230 /* Adjust the counter and pointer. */
4239 /* And set the rest of the array to NUL. */
4242 }
4244 {
4249 {
4253 }
4254 }
4256 /* Now, default-initialize any remaining elements. We don't need to
4257 do that if a) the type does not need constructing, or b) we've
4258 already initialized all the elements.
4260 We do need to keep going if we're copying an array. */
4263 /* With a constexpr default constructor, which we checked for when
4264 setting try_const above, default-initialization is equivalent to
4265 value-initialization, and build_value_init gives us something more
4266 friendly to maybe_constant_init. */
4271 && (num_initialized_elts
4273 {
4274 /* If the ITERATOR is lesser or equal to -1, then we don't have to loop;
4275 we've already initialized all the elements. */
4276 tree for_stmt;
4277 tree elt_init;
4278 tree to;
4286 complain);
4293 /* If the initializer is {}, then all elements are initialized from T{}.
4294 But for non-classes, that's the same as value-initialization. */
4296 {
4298 {
4300 }
4301 else
4302 {
4305 }
4306 }
4309 {
4310 tree from;
4313 {
4319 }
4320 else
4330 complain);
4331 else
4333 }
4335 {
4337 sorry
4341 explicit_value_init_p,
4343 }
4345 {
4349 }
4350 else
4351 {
4355 else
4356 {
4359 complain);
4361 }
4362 }
4368 {
4369 /* FIXME refs to earlier elts */
4372 {
4374 /* Don't fill the CONSTRUCTOR with zeros. */
4378 }
4379 else
4380 {
4384 else
4386 }
4389 {
4392 {
4395 }
4396 }
4397 }
4405 complain));
4408 complain));
4411 }
4413 /* Make sure to cleanup any partially constructed elements. */
4416 {
4417 tree e;
4420 complain);
4422 /* Flatten multi-dimensional array since build_vec_delete only
4423 expects one-dimensional array. */
4427 /* Avoid mixing signed and unsigned. */
4430 complain);
4439 }
4441 /* The value of the array initialization is the array itself, RVAL
4442 is a pointer to the first element. */
4453 {
4455 {
4458 }
4461 else
4463 }
4465 /* Now make the result have the correct type. */
4467 {
4472 }
4475 }
4477 /* Call the DTOR_KIND destructor for EXP. FLAGS are as for
4478 build_delete. */
4480 static tree
4482 tsubst_flags_t complain)
4483 {
4484 tree name;
4485 tree fn;
4487 {
4502 }
4507 flags,
4509 complain);
4510 }
4512 /* Generate a call to a destructor. TYPE is the type to cast ADDR to.
4513 ADDR is an expression which yields the store to be destroyed.
4514 AUTO_DELETE is the name of the destructor to call, i.e., either
4515 sfk_complete_destructor, sfk_base_destructor, or
4516 sfk_deleting_destructor.
4518 FLAGS is the logical disjunction of zero or more LOOKUP_
4519 flags. See cp-tree.h for more info. */
4521 tree
4524 {
4525 tree expr;
4532 /* Can happen when CURRENT_EXCEPTION_OBJECT gets its type
4533 set to `error_mark_node' before it gets properly cleaned up. */
4541 {
4543 {
4547 }
4550 }
4553 {
4556 /* We don't want to warn about delete of void*, only other
4557 incomplete types. Deleting other incomplete types
4558 invokes undefined behavior, but it is not ill-formed, so
4559 compile to something that would even do The Right Thing
4560 (TM) should the type have a trivial dtor and no delete
4561 operator. */
4563 {
4566 {
4569 "possible problem detected in invocation of "
4571 {
4574 "neither the destructor nor the class-specific "
4575 "operator delete will be called, even if they are "
4577 }
4578 }
4582 {
4585 {
4588 "deleting object of abstract class type %qT"
4589 " which has non-virtual destructor"
4591 else
4593 "deleting object of polymorphic class type %qT"
4594 " which has non-virtual destructor"
4596 }
4597 }
4598 }
4602 /* Throw away const and volatile on target type of addr. */
4604 }
4605 else
4606 {
4607 /* Don't check PROTECT here; leave that decision to the
4608 destructor. If the destructor is accessible, call it,
4609 else report error. */
4617 }
4620 {
4621 /* Make sure the destructor is callable. */
4623 {
4625 complain),
4629 }
4636 use_global_delete,
4639 complain);
4640 }
4641 else
4642 {
4645 tree ifexp;
4650 /* For `::delete x', we must not use the deleting destructor
4651 since then we would not be sure to get the global `operator
4652 delete'. */
4654 {
4655 /* We will use ADDR multiple times so we must save it. */
4658 /* Delete the object. */
4660 head,
4665 complain);
4666 /* Otherwise, treat this like a complete object destructor
4667 call. */
4669 }
4670 /* If the destructor is non-virtual, there is no deleting
4671 variant. Instead, we must explicitly call the appropriate
4672 `operator delete' here. */
4675 {
4676 /* We will use ADDR multiple times so we must save it. */
4678 /* Build the call. */
4680 addr,
4685 complain);
4686 /* Call the complete object destructor. */
4688 }
4691 {
4692 /* Make sure we have access to the member op delete, even though
4693 we'll actually be calling it from the destructor. */
4698 complain);
4699 }
4706 /* The delete operator must be called, regardless of whether
4707 the destructor throws.
4709 [expr.delete]/7 The deallocation function is called
4710 regardless of whether the destructor for the object or some
4711 element of the array throws an exception. */
4714 /* We need to calculate this before the dtor changes the vptr. */
4719 /* Explicit destructor call; don't check for null pointer. */
4721 else
4722 {
4723 /* Handle deleting a null pointer. */
4729 /* This is a compiler generated comparison, don't emit
4730 e.g. -Wnonnull-compare warning for it. */
4733 }
4739 }
4740 }
4742 /* At the beginning of a destructor, push cleanups that will call the
4743 destructors for our base classes and members.
4745 Called from begin_destructor_body. */
4747 void
4749 {
4752 tree member;
4753 tree expr;
4756 /* Run destructors for all virtual baseclasses. */
4759 {
4760 tree cond = (condition_conversion
4762 current_in_charge_parm,
4763 integer_two_node)));
4765 /* The CLASSTYPE_VBASECLASSES vector is in initialization
4766 order, which is also the right order for pushing cleanups. */
4769 {
4771 {
4773 base_dtor_identifier,
4774 NULL,
4775 base_binfo,
4776 (LOOKUP_NORMAL
4778 tf_warning_or_error);
4780 {
4784 }
4785 }
4786 }
4787 }
4789 /* Take care of the remaining baseclasses. */
4792 {
4798 base_dtor_identifier,
4801 tf_warning_or_error);
4804 }
4806 /* Don't automatically destroy union members. */
4812 {
4821 {
4822 tree this_member = (build_class_member_access_expr
4826 tf_warning_or_error));
4828 sfk_complete_destructor,
4833 }
4834 }
4835 }
4837 /* Build a C++ vector delete expression.
4838 MAXINDEX is the number of elements to be deleted.
4839 ELT_SIZE is the nominal size of each element in the vector.
4840 BASE is the expression that should yield the store to be deleted.
4841 This function expands (or synthesizes) these calls itself.
4842 AUTO_DELETE_VEC says whether the container (vector) should be deallocated.
4844 This also calls delete for virtual baseclasses of elements of the vector.
4846 Update: MAXINDEX is no longer needed. The size can be extracted from the
4847 start of the vector for pointers, and from the type for arrays. We still
4848 use MAXINDEX for arrays because it happens to already have one of the
4849 values we'd have to extract. (We could use MAXINDEX with pointers to
4850 confirm the size, and trap if the numbers differ; not clear that it'd
4851 be worth bothering.) */
4853 tree
4855 special_function_kind auto_delete_vec,
4857 {
4858 tree type;
4859 tree rval;
4865 {
4866 /* Step back one from start of vector, and read dimension. */
4867 tree cookie_addr;
4872 {
4875 }
4880 cookie_addr);
4882 }
4884 {
4885 /* Get the total number of things in the array, maxindex is a
4886 bad name. */
4893 {
4896 }
4897 }
4898 else
4899 {
4903 }
4911 }