| blob | 15046b4257bc7aac7b561801820ff997d71e123c |
1 /* Handle initialization things in C++.
2 Copyright (C) 1987-2018 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com)
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
21 /* High-level class interface. */
54 /* We are about to generate some complex initialization code.
55 Conceptually, it is all a single expression. However, we may want
56 to include conditionals, loops, and other such statement-level
57 constructs. Therefore, we build the initialization code inside a
58 statement-expression. This function starts such an expression.
59 STMT_EXPR_P and COMPOUND_STMT_P are filled in by this function;
60 pass them back to finish_init_stmts when the expression is
61 complete. */
63 static bool
65 {
72 }
74 /* Finish out the statement-expression begun by the previous call to
75 begin_init_stmts. Returns the statement-expression itself. */
77 static tree
79 {
87 }
89 /* Constructors */
91 /* Called from initialize_vtbl_ptrs via dfs_walk. BINFO is the base
92 which we want to initialize the vtable pointer for, DATA is
93 TREE_LIST whose TREE_VALUE is the this ptr expression. */
95 static tree
97 {
102 {
106 tf_warning_or_error);
109 }
112 }
114 /* Initialize all the vtable pointers in the object pointed to by
115 ADDR. */
117 void
119 {
120 tree list;
121 tree type;
126 /* Walk through the hierarchy, initializing the vptr in each base
127 class. We do these in pre-order because we can't find the virtual
128 bases for a class until we've initialized the vtbl for that
129 class. */
131 }
133 /* Return an expression for the zero-initialization of an object with
134 type T. This expression will either be a constant (in the case
135 that T is a scalar), or a CONSTRUCTOR (in the case that T is an
136 aggregate), or NULL (in the case that T does not require
137 initialization). In either case, the value can be used as
138 DECL_INITIAL for a decl of the indicated TYPE; it is a valid static
139 initializer. If NELTS is non-NULL, and TYPE is an ARRAY_TYPE, NELTS
140 is the number of elements in the array. If STATIC_STORAGE_P is
141 TRUE, initializers are only generated for entities for which
142 zero-initialization does not simply mean filling the storage with
143 zero bytes. FIELD_SIZE, if non-NULL, is the bit size of the field,
144 subfields with bit positions at or above that bit size shouldn't
145 be added. Note that this only works when the result is assigned
146 to a base COMPONENT_REF; if we only have a pointer to the base subobject,
147 expand_assignment will end up clearing the full size of TYPE. */
149 static tree
151 tree field_size)
152 {
155 /* [dcl.init]
157 To zero-initialize an object of type T means:
159 -- if T is a scalar type, the storage is set to the value of zero
160 converted to T.
162 -- if T is a non-union class type, the storage for each nonstatic
163 data member and each base-class subobject is zero-initialized.
165 -- if T is a union type, the storage for its first data member is
166 zero-initialized.
168 -- if T is an array type, the storage for each element is
169 zero-initialized.
171 -- if T is a reference type, no initialization is performed. */
176 ;
178 /* In order to save space, we do not explicitly build initializers
179 for items that do not need them. GCC's semantics are that
180 items with static storage duration that are not otherwise
181 initialized are initialized to zero. */
182 ;
190 {
191 tree field;
194 /* Iterate over the fields, building initializations. */
196 {
203 /* Don't add virtual bases for base classes if they are beyond
204 the size of the current field, that means it is present
205 somewhere else in the object. */
207 {
212 }
214 /* Note that for class types there will be FIELD_DECLs
215 corresponding to base classes as well. Thus, iterating
216 over TYPE_FIELDs will result in correct initialization of
217 all of the subobjects. */
219 {
220 tree new_field_size
227 static_storage_p,
228 new_field_size);
231 }
233 /* For unions, only the first field is initialized. */
236 }
238 /* Build a constructor to contain the initializations. */
240 }
242 {
243 tree max_index;
246 /* Iterate over the array elements, building initializations. */
251 else
254 /* If we have an error_mark here, we should just return error mark
255 as we don't know the size of the array yet. */
260 /* A zero-sized array, which is accepted as an extension, will
261 have an upper bound of -1. */
263 {
264 constructor_elt ce;
266 /* If this is a one element array, we just use a regular init. */
269 else
271 max_index);
277 {
280 }
281 }
283 /* Build a constructor to contain the initializations. */
285 }
288 else
289 {
292 }
294 /* In all cases, the initializer is a constant. */
299 }
301 /* Return an expression for the zero-initialization of an object with
302 type T. This expression will either be a constant (in the case
303 that T is a scalar), or a CONSTRUCTOR (in the case that T is an
304 aggregate), or NULL (in the case that T does not require
305 initialization). In either case, the value can be used as
306 DECL_INITIAL for a decl of the indicated TYPE; it is a valid static
307 initializer. If NELTS is non-NULL, and TYPE is an ARRAY_TYPE, NELTS
308 is the number of elements in the array. If STATIC_STORAGE_P is
309 TRUE, initializers are only generated for entities for which
310 zero-initialization does not simply mean filling the storage with
311 zero bytes. */
313 tree
315 {
317 }
319 /* Return a suitable initializer for value-initializing an object of type
320 TYPE, as described in [dcl.init]. */
322 tree
324 {
325 /* [dcl.init]
327 To value-initialize an object of type T means:
329 - if T is a class type (clause 9) with either no default constructor
330 (12.1) or a default constructor that is user-provided or deleted,
331 then the object is default-initialized;
333 - if T is a (possibly cv-qualified) class type without a user-provided
334 or deleted default constructor, then the object is zero-initialized
335 and the semantic constraints for default-initialization are checked,
336 and if T has a non-trivial default constructor, the object is
337 default-initialized;
339 - if T is an array type, then each element is value-initialized;
341 - otherwise, the object is zero-initialized.
343 A program that calls for default-initialization or
344 value-initialization of an entity of reference type is ill-formed. */
346 /* The AGGR_INIT_EXPR tweaking below breaks in templates. */
352 {
353 tree ctor =
356 complain);
366 {
367 /* This is a class that needs constructing, but doesn't have
368 a user-provided constructor. So we need to zero-initialize
369 the object and then call the implicitly defined ctor.
370 This will be handled in simplify_aggr_init_expr. */
373 }
374 }
376 /* Discard any access checking during subobject initialization;
377 the checks are implied by the call to the ctor which we have
378 verified is OK (cpp0x/defaulted46.C). */
383 }
385 /* Like build_value_init, but don't call the constructor for TYPE. Used
386 for base initializers. */
388 tree
390 {
392 {
396 }
397 /* FIXME the class and array cases should just use digest_init once it is
398 SFINAE-enabled. */
400 {
405 {
406 tree field;
409 /* Iterate over the fields, building initializations. */
411 {
422 /* We could skip vfields and fields of types with
423 user-defined constructors, but I think that won't improve
424 performance at all; it should be simpler in general just
425 to zero out the entire object than try to only zero the
426 bits that actually need it. */
428 /* Note that for class types there will be FIELD_DECLs
429 corresponding to base classes as well. Thus, iterating
430 over TYPE_FIELDs will result in correct initialization of
431 all of the subobjects. */
440 /* We shouldn't have gotten here for anything that would need
441 non-trivial initialization, and gimplify_init_ctor_preeval
442 would need to be fixed to allow it. */
445 }
447 /* Build a constructor to contain the zero- initializations. */
449 }
450 }
452 {
455 /* Iterate over the array elements, building initializations. */
458 /* If we have an error_mark here, we should just return error mark
459 as we don't know the size of the array yet. */
461 {
464 type);
466 }
469 /* A zero-sized array, which is accepted as an extension, will
470 have an upper bound of -1. */
472 {
473 constructor_elt ce;
475 /* If this is a one element array, we just use a regular init. */
478 else
489 /* We shouldn't have gotten here for anything that would need
490 non-trivial initialization, and gimplify_init_ctor_preeval
491 would need to be fixed to allow it. */
494 }
496 /* Build a constructor to contain the initializations. */
498 }
500 {
504 }
506 {
510 }
513 }
515 /* Initialize current class with INIT, a TREE_LIST of
516 arguments for a target constructor. If TREE_LIST is void_type_node,
517 an empty initializer list was given. */
519 static void
521 {
527 tf_warning_or_error));
529 {
531 LOOKUP_NORMAL
532 |LOOKUP_NONVIRTUAL
538 }
539 }
541 /* Return the non-static data initializer for FIELD_DECL MEMBER. */
545 tree
547 {
548 tree init;
553 {
555 location_t expr_loc
562 /* Check recursive instantiation. */
564 {
569 }
570 else
571 {
582 {
586 }
594 /* Do deferred instantiation of the NSDMI. */
595 init = (tsubst_copy_and_build
606 {
610 }
613 {
616 }
620 }
621 }
622 else
626 {
628 {
633 }
635 }
638 {
641 }
642 else
643 {
644 /* Use a PLACEHOLDER_EXPR when we don't have a 'this' parameter to
645 refer to; constexpr evaluation knows what to do with it. */
648 }
650 /* Strip redundant TARGET_EXPR so we don't need to remap it, and
651 so the aggregate init code below will see a CONSTRUCTOR. */
657 /* Now put it back so C++17 copy elision works. */
663 }
665 /* Diagnose the flexible array MEMBER if its INITializer is non-null
666 and return true if so. Otherwise return false. */
668 bool
670 {
678 /* Point at the flexible array member declaration if it's initialized
679 in-class, and at the ctor if it's initialized in a ctor member
680 initializer list. */
681 location_t loc;
683 || !current_function_decl
686 else
691 }
693 /* If INIT's value can come from a call to std::initializer_list<T>::begin,
694 return that function. Otherwise, NULL_TREE. */
696 static tree
698 {
704 {
712 }
719 }
721 /* If INIT initializing MEMBER is copying the address of the underlying array
722 of an initializer_list, warn. */
724 static void
726 {
747 "initializing %qD from %qE does not extend the lifetime "
749 }
751 /* Initialize MEMBER, a FIELD_DECL, with INIT, a TREE_LIST of
752 arguments. If TREE_LIST is void_type_node, an empty initializer
753 list was given; if NULL_TREE no initializer was given. */
755 static void
757 {
758 tree decl;
761 /* Use the non-static data member initializer if there was no
762 mem-initializer for this field. */
769 /* Effective C++ rule 12 requires that all data members be
770 initialized. */
774 member);
776 /* Get an lvalue for the data member. */
780 tf_warning_or_error);
786 {
788 /* Handle references. */
795 member);
796 }
799 {
800 /* mem() means value-initialization. */
802 {
806 }
807 else
808 {
814 }
815 }
816 /* Deal with this here, as we will get confused if we try to call the
817 assignment op for an anonymous union. This can happen in a
818 synthesized copy constructor. */
820 {
822 {
825 }
826 }
829 /* Pre-digested NSDMI. */
832 /* { } mem-initializer. */
837 {
838 /* With references and list-initialization, we need to deal with
839 extending temporary lifetimes. 12.2p5: "A temporary bound to a
840 reference member in a constructor’s ctor-initializer (12.6.2)
841 persists until the constructor exits." */
846 tf_warning_or_error);
848 {
853 }
856 /* A FIELD_DECL doesn't really have a suitable lifetime, but
857 make_temporary_var_for_ref_to_temp will treat it as automatic and
858 set_up_extended_ref_temp wants to use the decl in a warning. */
868 }
871 {
873 {
875 {
876 /* Check to make sure the member initializer is valid and
877 something like a CONSTRUCTOR in: T a[] = { 1, 2 } and
878 if it isn't, return early to avoid triggering another
879 error below. */
885 else
890 }
894 {
896 {
897 /* Initialize the array only if it's not a flexible
898 array member (i.e., if it has an upper bound). */
902 }
903 }
904 else
906 }
907 else
908 {
915 {
916 /* TYPE_NEEDS_CONSTRUCTING can be set just because we have a
917 vtable; still give this diagnostic. */
918 auto_diagnostic_group d;
923 }
925 tf_warning_or_error));
926 }
927 }
928 else
929 {
931 {
932 tree core_type;
933 /* member traversal: note it leaves init NULL */
935 {
936 auto_diagnostic_group d;
941 }
943 {
944 auto_diagnostic_group d;
949 }
959 }
961 /* There was an explicit member initialization. Do some work
962 in that case. */
964 tf_warning_or_error);
968 /* Reject a member initializer for a flexible array member. */
972 tf_warning_or_error));
973 }
976 {
977 tree expr;
982 tf_warning_or_error);
985 tf_warning_or_error);
990 }
991 }
993 /* Returns a TREE_LIST containing (as the TREE_PURPOSE of each node) all
994 the FIELD_DECLs on the TYPE_FIELDS list for T, in reverse order. */
996 static tree
998 {
999 tree fields;
1001 /* Note whether or not T is a union. */
1006 {
1007 tree fieldtype;
1009 /* Skip CONST_DECLs for enumeration constants and so forth. */
1015 /* For an anonymous struct or union, we must recursively
1016 consider the fields of the anonymous type. They can be
1017 directly initialized from the constructor. */
1019 {
1020 /* Add this field itself. Synthesized copy constructors
1021 initialize the entire aggregate. */
1023 /* And now add the fields in the anonymous aggregate. */
1026 }
1027 /* Add this field. */
1030 }
1033 }
1035 /* Return the innermost aggregate scope for FIELD, whether that is
1036 the enclosing class or an anonymous aggregate within it. */
1038 static tree
1040 {
1043 else
1045 }
1047 /* The MEM_INITS are a TREE_LIST. The TREE_PURPOSE of each list gives
1048 a FIELD_DECL or BINFO in T that needs initialization. The
1049 TREE_VALUE gives the initializer, or list of initializer arguments.
1051 Return a TREE_LIST containing all of the initializations required
1052 for T, in the order in which they should be performed. The output
1053 list has the same format as the input. */
1055 static tree
1057 {
1058 tree init;
1060 tree sorted_inits;
1061 tree next_subobject;
1066 /* Build up a list of initializations. The TREE_PURPOSE of entry
1067 will be the subobject (a FIELD_DECL or BINFO) to initialize. The
1068 TREE_VALUE will be the constructor arguments, or NULL if no
1069 explicit initialization was provided. */
1072 /* Process the virtual bases. */
1077 /* Process the direct bases. */
1083 /* Process the non-static data members. */
1085 /* Reverse the entire list of initializations, so that they are in
1086 the order that they will actually be performed. */
1089 /* If the user presented the initializers in an order different from
1090 that in which they will actually occur, we issue a warning. Keep
1091 track of the next subobject which can be explicitly initialized
1092 without issuing a warning. */
1095 /* Go through the explicit initializers, filling in TREE_PURPOSE in
1096 the SORTED_INITS. */
1098 {
1099 tree subobject;
1100 tree subobject_init;
1104 /* If the explicit initializers are in sorted order, then
1105 SUBOBJECT will be NEXT_SUBOBJECT, or something following
1106 it. */
1108 subobject_init;
1113 /* Issue a warning if the explicit initializer order does not
1114 match that which will actually occur.
1115 ??? Are all these on the correct lines? */
1117 {
1122 else
1128 else
1132 }
1134 /* Look again, from the beginning of the list. */
1136 {
1140 }
1142 /* It is invalid to initialize the same subobject more than
1143 once. */
1145 {
1149 subobject);
1150 else
1153 subobject);
1154 }
1156 /* Record the initialization. */
1159 }
1161 /* [class.base.init]
1163 If a ctor-initializer specifies more than one mem-initializer for
1164 multiple members of the same union (including members of
1165 anonymous unions), the ctor-initializer is ill-formed.
1167 Here we also splice out uninitialized union members. */
1169 {
1173 {
1174 tree field;
1175 tree ctx;
1181 /* Skip base classes. */
1185 /* If this is an anonymous aggregate with no explicit initializer,
1186 splice it out. */
1190 /* See if this field is a member of a union, or a member of a
1191 structure contained in a union, etc. */
1194 /* If this field is not a member of a union, skip it. */
1199 /* If this union member has no explicit initializer and no NSDMI,
1200 splice it out. */
1203 else
1206 /* It's only an error if we have two initializers for the same
1207 union type. */
1209 {
1212 }
1214 /* See if LAST_FIELD and the field initialized by INIT are
1215 members of the same union (or the union itself). If so, there's
1216 a problem, unless they're actually members of the same structure
1217 which is itself a member of a union. For example, given:
1219 union { struct { int i; int j; }; };
1221 initializing both `i' and `j' makes sense. */
1222 ctx = common_enclosing_class
1228 {
1229 /* A mem-initializer hides an NSDMI. */
1234 else
1235 {
1238 ctx);
1240 }
1241 }
1245 next:
1248 splice:
1251 }
1252 }
1255 }
1257 /* Callback for cp_walk_tree to mark all PARM_DECLs in a tree as read. */
1259 static tree
1261 {
1266 }
1268 /* Initialize all bases and members of CURRENT_CLASS_TYPE. MEM_INITS
1269 is a TREE_LIST giving the explicit mem-initializer-list for the
1270 constructor. The TREE_PURPOSE of each entry is a subobject (a
1271 FIELD_DECL or a BINFO) of the CURRENT_CLASS_TYPE. The TREE_VALUE
1272 is a TREE_LIST giving the arguments to the constructor or
1273 void_type_node for an empty list of arguments. */
1275 void
1277 {
1280 /* We will already have issued an error message about the fact that
1281 the type is incomplete. */
1288 {
1289 /* Delegating constructor. */
1293 }
1299 /* Sort the mem-initializers into the order in which the
1300 initializations should be performed. */
1305 /* Initialize base classes. */
1309 {
1313 /* We already have issued an error message. */
1317 /* Suppress access control when calling the inherited ctor. */
1319 && flag_new_inheriting_ctors
1325 {
1326 /* If these initializations are taking place in a copy constructor,
1327 the base class should probably be explicitly initialized if there
1328 is a user-defined constructor in the base class (other than the
1329 default constructor, which will be called anyway). */
1337 }
1339 /* Initialize the base. */
1341 {
1342 tree base_addr;
1348 arguments,
1349 flags,
1350 tf_warning_or_error);
1352 }
1354 /* C++14 DR1658 Means we do not have to construct vbases of
1355 abstract classes. */
1357 else
1358 /* When not constructing vbases of abstract classes, at least mark
1359 the arguments expressions as read to avoid
1360 -Wunused-but-set-parameter false positives. */
1365 }
1368 /* Initialize the vptrs. */
1371 /* Initialize the data members. */
1373 {
1377 }
1378 }
1380 /* Returns the address of the vtable (i.e., the value that should be
1381 assigned to the vptr) for BINFO. */
1383 tree
1385 {
1387 tree vtbl;
1390 /* If this is a virtual primary base, then the vtable we want to store
1391 is that for the base this is being used as the primary base of. We
1392 can't simply skip the initialization, because we may be expanding the
1393 inits of a subobject constructor where the virtual base layout
1394 can be different. */
1398 /* Figure out what vtable BINFO's vtable is based on, and mark it as
1399 used. */
1403 /* Now compute the address to use when initializing the vptr. */
1409 }
1411 /* This code sets up the virtual function tables appropriate for
1412 the pointer DECL. It is a one-ply initialization.
1414 BINFO is the exact type that DECL is supposed to be. In
1415 multiple inheritance, this might mean "C's A" if C : A, B. */
1417 static void
1419 {
1421 tree vtt_index;
1423 /* Compute the initializer for vptr. */
1426 /* We may get this vptr from a VTT, if this is a subobject
1427 constructor or subobject destructor. */
1430 {
1431 tree vtbl2;
1432 tree vtt_parm;
1434 /* Compute the value to use, when there's a VTT. */
1440 /* The actual initializer is the VTT value only in the subobject
1441 constructor. In maybe_clone_body we'll substitute NULL for
1442 the vtt_parm in the case of the non-subobject constructor. */
1444 }
1446 /* Compute the location of the vtpr. */
1451 /* Assign the vtable to the vptr. */
1455 }
1457 /* If an exception is thrown in a constructor, those base classes already
1458 constructed must be destroyed. This function creates the cleanup
1459 for BINFO, which has just been constructed. If FLAG is non-NULL,
1460 it is a DECL which is nonzero when this base needs to be
1461 destroyed. */
1463 static void
1465 {
1466 tree expr;
1471 /* Call the destructor. */
1473 base_dtor_identifier,
1474 NULL,
1475 binfo,
1477 tf_warning_or_error);
1489 }
1491 /* Construct the virtual base-class VBASE passing the ARGUMENTS to its
1492 constructor. */
1494 static void
1496 {
1497 tree inner_if_stmt;
1498 tree exp;
1499 tree flag;
1501 /* If there are virtual base classes with destructors, we need to
1502 emit cleanups to destroy them if an exception is thrown during
1503 the construction process. These exception regions (i.e., the
1504 period during which the cleanups must occur) begin from the time
1505 the construction is complete to the end of the function. If we
1506 create a conditional block in which to initialize the
1507 base-classes, then the cleanup region for the virtual base begins
1508 inside a block, and ends outside of that block. This situation
1509 confuses the sjlj exception-handling code. Therefore, we do not
1510 create a single conditional block, but one for each
1511 initialization. (That way the cleanup regions always begin
1512 in the outer block.) We trust the back end to figure out
1513 that the FLAG will not change across initializations, and
1514 avoid doing multiple tests. */
1519 /* Compute the location of the virtual base. If we're
1520 constructing virtual bases, then we must be the most derived
1521 class. Therefore, we don't have to look up the virtual base;
1522 we already know where it is. */
1531 }
1533 /* Find the context in which this FIELD can be initialized. */
1535 static tree
1537 {
1540 /* Anonymous union members can be initialized in the first enclosing
1541 non-anonymous union context. */
1545 }
1547 /* Function to give error message if member initialization specification
1548 is erroneous. FIELD is the member we decided to initialize.
1549 TYPE is the type for which the initialization is being performed.
1550 FIELD must be a member of TYPE.
1552 MEMBER_NAME is the name of the member. */
1554 static int
1556 {
1560 {
1562 member_name);
1564 }
1566 {
1569 field);
1571 }
1573 {
1577 }
1579 {
1581 member_name);
1583 }
1586 }
1588 /* NAME is a FIELD_DECL, an IDENTIFIER_NODE which names a field, or it
1589 is a _TYPE node or TYPE_DECL which names a base for that type.
1590 Check the validity of NAME, and return either the base _TYPE, base
1591 binfo, or the FIELD_DECL of the member. If NAME is invalid, return
1592 NULL_TREE and issue a diagnostic.
1594 An old style unnamed direct single base construction is permitted,
1595 where NAME is NULL. */
1597 tree
1599 {
1600 tree basetype;
1601 tree field;
1607 {
1608 /* This is an obsolete unnamed base class initializer. The
1609 parser will already have warned about its use. */
1611 {
1614 current_class_type);
1617 basetype = BINFO_TYPE
1622 current_class_type);
1624 }
1625 }
1627 {
1630 }
1633 else
1637 {
1638 tree class_binfo;
1639 tree direct_binfo;
1640 tree virtual_binfo;
1651 /* Look for a direct base. */
1656 /* Look for a virtual base -- unless the direct base is itself
1657 virtual. */
1661 /* [class.base.init]
1663 If a mem-initializer-id is ambiguous because it designates
1664 both a direct non-virtual base class and an inherited virtual
1665 base class, the mem-initializer is ill-formed. */
1667 {
1669 basetype);
1671 }
1674 {
1678 else
1682 }
1685 }
1686 else
1687 {
1690 else
1695 }
1698 }
1700 /* This is like `expand_member_init', only it stores one aggregate
1701 value into another.
1703 INIT comes in two flavors: it is either a value which
1704 is to be stored in EXP, or it is a parameter list
1705 to go to a constructor, which will operate on EXP.
1706 If INIT is not a parameter list for a constructor, then set
1707 LOOKUP_ONLYCONVERTING.
1708 If FLAGS is LOOKUP_ONLYCONVERTING then it is the = init form of
1709 the initializer, if FLAGS is 0, then it is the (init) form.
1710 If `init' is a CONSTRUCTOR, then we emit a warning message,
1711 explaining that such initializations are invalid.
1713 If INIT resolves to a CALL_EXPR which happens to return
1714 something of the type we are looking for, then we know
1715 that we can safely use that call to perform the
1716 initialization.
1718 The virtual function table pointer cannot be set up here, because
1719 we do not really know its type.
1721 This never calls operator=().
1723 When initializing, nothing is CONST.
1725 A default copy constructor may have to be used to perform the
1726 initialization.
1728 A constructor or a conversion operator may have to be used to
1729 perform the initialization, but not both, as it would be ambiguous. */
1731 tree
1733 {
1734 tree stmt_expr;
1735 tree compound_stmt;
1745 location_t init_loc = (init
1753 {
1758 {
1763 {
1764 /* Wrap the initializer in a CONSTRUCTOR so that build_vec_init
1765 recognizes it as direct-initialization. */
1769 }
1770 }
1771 else
1772 {
1773 /* Must arrange to initialize each element of EXP
1774 from elements of INIT. */
1783 && (!from_array
1785 /* Can happen, eg, handling the compound-literals
1786 extension (ext/complit12.C). */
1788 {
1793 }
1794 }
1798 from_array,
1799 complain);
1803 /* Restore the type of init unless it was used directly. */
1807 }
1829 /* Just know that we've seen something for this node. */
1833 }
1835 static void
1837 tsubst_flags_t complain)
1838 {
1841 /* It fails because there may not be a constructor which takes
1842 its own type as the first (or only parameter), but which does
1843 take other types via a conversion. So, if the thing initializing
1844 the expression is a unit element of type X, first try X(X&),
1845 followed by initialization by X. If neither of these work
1846 out, then look hard. */
1847 tree rval;
1850 /* If we have direct-initialization from an initializer list, pull
1851 it out of the TREE_LIST so the code below can see it. */
1854 {
1858 /* Only call reshape_init if it has not been called earlier
1859 by the callers. */
1862 }
1866 /* A brace-enclosed initializer for an aggregate. In C++0x this can
1867 happen for direct-initialization, too. */
1870 /* A CONSTRUCTOR of the target's type is a previously digested
1871 initializer, whether that happened just above or in
1872 cp_parser_late_parsing_nsdmi.
1874 A TARGET_EXPR with TARGET_EXPR_DIRECT_INIT_P or TARGET_EXPR_LIST_INIT_P
1875 set represents the whole initialization, so we shouldn't build up
1876 another ctor call. */
1883 {
1884 /* Early initialization via a TARGET_EXPR only works for
1885 complete objects. */
1892 }
1896 {
1897 /* Base subobjects should only get direct-initialization. */
1901 /* Do nothing. We hit this in two cases: Reference initialization,
1902 where we aren't initializing a real variable, so we don't want
1903 to run a new constructor; and catching an exception, where we
1904 have already built up the constructor call so we could wrap it
1906 else
1911 /* We need to protect the initialization of a catch parm with a
1912 call to terminate(), which shows up as a MUST_NOT_THROW_EXPR
1913 around the TARGET_EXPR for the copy constructor. See
1914 initialize_handler_parm. */
1915 {
1919 }
1920 else
1925 }
1930 {
1934 }
1935 else
1940 {
1941 /* Delegating constructor. */
1942 tree complete;
1943 tree base;
1946 /* Unshare the arguments for the second call. */
1949 {
1952 }
1955 complain);
1961 complain);
1964 }
1965 else
1966 {
1971 complain);
1972 }
1978 {
1981 {
1985 }
1986 }
1988 /* FIXME put back convert_to_void? */
1991 }
1993 /* This function is responsible for initializing EXP with INIT
1994 (if any).
1996 BINFO is the binfo of the type for who we are performing the
1997 initialization. For example, if W is a virtual base class of A and B,
1998 and C : A, B.
1999 If we are initializing B, then W must contain B's W vtable, whereas
2000 were we initializing C, W must contain C's W vtable.
2002 TRUE_EXP is nonzero if it is the true expression being initialized.
2003 In this case, it may be EXP, or may just contain EXP. The reason we
2004 need this is because if EXP is a base element of TRUE_EXP, we
2005 don't necessarily know by looking at EXP where its virtual
2006 baseclass fields should really be pointing. But we do know
2007 from TRUE_EXP. In constructors, we don't know anything about
2008 the value being initialized.
2010 FLAGS is just passed to `build_new_method_call'. See that function
2011 for its description. */
2013 static void
2015 tsubst_flags_t complain)
2016 {
2022 /* Use a function returning the desired type to initialize EXP for us.
2023 If the function is a constructor, and its first argument is
2024 NULL_TREE, know that it was meant for us--just slide exp on
2025 in and expand the constructor. Constructors now come
2026 as TARGET_EXPRs. */
2030 {
2032 /* If store_init_value returns NULL_TREE, the INIT has been
2033 recorded as the DECL_INITIAL for EXP. That means there's
2034 nothing more we have to do. */
2040 }
2042 /* List-initialization from {} becomes value-initialization for non-aggregate
2043 classes with default constructors. Handle this here when we're
2044 initializing a base, so protected access works. */
2046 {
2053 }
2055 /* If an explicit -- but empty -- initializer list was present,
2056 that's value-initialization. */
2058 {
2059 /* If the type has data but no user-provided ctor, we need to zero
2060 out the object. */
2063 {
2066 /* Don't clobber already initialized virtual bases. */
2069 field_size);
2072 }
2074 /* If we don't need to mess with the constructor at all,
2075 then we're done. */
2079 /* Otherwise fall through and call the constructor. */
2081 }
2083 /* We know that expand_default_init can handle everything we want
2084 at this point. */
2086 }
2088 /* Report an error if TYPE is not a user-defined, class type. If
2089 OR_ELSE is nonzero, give an error message. */
2091 int
2093 {
2098 {
2102 }
2104 }
2106 tree
2108 {
2114 else
2116 }
2118 /* Build a reference to a member of an aggregate. This is not a C++
2119 `&', but really something which can have its address taken, and
2120 then act as a pointer to member, for example TYPE :: FIELD can have
2121 its address taken by saying & TYPE :: FIELD. ADDRESS_P is true if
2122 this expression is the operand of "&".
2124 @@ Prints out lousy diagnostics for operator <typename>
2125 @@ fields.
2127 @@ This function should be rewritten and placed in search.c. */
2129 tree
2131 tsubst_flags_t complain)
2132 {
2133 tree decl;
2136 /* class templates can come in as TEMPLATE_DECLs here. */
2149 /* Callers should call mark_used before this point. */
2154 {
2158 }
2160 /* Entities other than non-static members need no further
2161 processing. */
2168 {
2172 }
2174 /* Set up BASEBINFO for member lookup. */
2177 /* A lot of this logic is now handled in lookup_member. */
2179 {
2180 /* Go from the TREE_BASELINK to the member function info. */
2184 {
2185 /* Get rid of a potential OVERLOAD around it. */
2188 /* Unique functions are handled easily. */
2190 /* For non-static member of base class, we need a special rule
2191 for access checking [class.protected]:
2193 If the access is to form a pointer to member, the
2194 nested-name-specifier shall name the derived class
2195 (or any class derived from that class). */
2200 complain);
2201 else
2203 complain);
2209 }
2210 else
2212 }
2214 {
2215 /* We need additional test besides the one in
2216 check_accessibility_of_qualified_id in case it is
2217 a pointer to non-static member. */
2219 complain))
2221 }
2224 {
2225 /* If MEMBER is non-static, then the program has fallen afoul of
2226 [expr.prim]:
2228 An id-expression that denotes a nonstatic data member or
2229 nonstatic member function of a class can only be used:
2231 -- as part of a class member access (_expr.ref_) in which the
2232 object-expression refers to the member's class or a class
2233 derived from that class, or
2235 -- to form a pointer to member (_expr.unary.op_), or
2237 -- in the body of a nonstatic member function of that class or
2238 of a class derived from that class (_class.mfct.nonstatic_), or
2240 -- in a mem-initializer for a constructor for that class or for
2241 a class derived from that class (_class.base.init_). */
2243 {
2244 /* Build a representation of the qualified name suitable
2245 for use as the operand to "&" -- even though the "&" is
2246 not actually present. */
2248 /* In Microsoft mode, treat a non-static member function as if
2249 it were a pointer-to-member. */
2251 {
2254 }
2259 }
2261 {
2265 }
2267 }
2272 }
2274 /* If DECL is a scalar enumeration constant or variable with a
2275 constant initializer, return the initializer (or, its initializers,
2276 recursively); otherwise, return DECL. If STRICT_P, the
2277 initializer is only returned if DECL is a
2278 constant-expression. If RETURN_AGGREGATE_CST_OK_P, it is ok to
2279 return an aggregate constant. */
2281 static tree
2283 {
2288 {
2289 tree init;
2290 /* If DECL is a static data member in a template
2291 specialization, we must instantiate it here. The
2292 initializer for the static data member is not processed
2293 until needed; we need it now. */
2297 {
2300 /* Treat the error as a constant to avoid cascading errors on
2301 excessively recursive template instantiation (c++/9335). */
2303 else
2305 }
2306 /* Initializers in templates are generally expanded during
2307 instantiation, so before that for const int i(2)
2308 INIT is a TREE_LIST with the actual initializer as
2309 TREE_VALUE. */
2311 && init
2315 /* Instantiate a non-dependent initializer for user variables. We
2316 mustn't do this for the temporary for an array compound literal;
2317 trying to instatiate the initializer will keep creating new
2318 temporaries until we crash. Probably it's not useful to do it for
2319 other artificial variables, either. */
2325 || (!return_aggregate_cst_ok_p
2326 /* Unless RETURN_AGGREGATE_CST_OK_P is true, do not
2327 return an aggregate constant (of which string
2328 literals are a special case), as we do not want
2329 to make inadvertent copies of such entities, and
2330 we must be sure that their addresses are the
2331 same everywhere. */
2335 /* Don't return a CONSTRUCTOR for a variable with partial run-time
2336 initialization, since it doesn't represent the entire value. */
2340 /* If the variable has a dynamic initializer, don't use its
2341 DECL_INITIAL which doesn't reflect the real value. */
2348 }
2350 }
2352 /* If DECL is a CONST_DECL, or a constant VAR_DECL initialized by constant
2353 of integral or enumeration type, or a constexpr variable of scalar type,
2354 then return that value. These are those variables permitted in constant
2355 expressions by [5.19/1]. */
2357 tree
2359 {
2362 }
2364 /* Like scalar_constant_value, but can also return aggregate initializers. */
2366 tree
2368 {
2371 }
2373 /* A more relaxed version of scalar_constant_value, used by the
2374 common C/C++ code. */
2376 tree
2378 {
2381 }
2382 \f
2383 /* Common subroutines of build_new and build_vec_delete. */
2384 \f
2385 /* Build and return a NEW_EXPR. If NELTS is non-NULL, TYPE[NELTS] is
2386 the type of the object being allocated; otherwise, it's just TYPE.
2387 INIT is the initializer, if any. USE_GLOBAL_NEW is true if the
2388 user explicitly wrote "::operator new". PLACEMENT, if non-NULL, is
2389 a vector of arguments to be provided as arguments to a placement
2390 new operator. This routine performs no semantic checks; it just
2391 creates and returns a NEW_EXPR. */
2393 static tree
2396 {
2397 tree init_list;
2398 tree new_expr;
2400 /* If INIT is NULL, the we want to store NULL_TREE in the NEW_EXPR.
2401 If INIT is not NULL, then we want to store VOID_ZERO_NODE. This
2402 permits us to distinguish the case of a missing initializer "new
2403 int" from an empty initializer "new int()". */
2408 else
2413 init_list);
2418 }
2420 /* Diagnose uninitialized const members or reference members of type
2421 TYPE. USING_NEW is used to disambiguate the diagnostic between a
2422 new expression without a new-initializer and a declaration. Returns
2423 the error count. */
2425 static int
2428 {
2429 tree field;
2436 {
2437 tree field_type;
2448 {
2451 {
2453 {
2457 else
2459 }
2460 else
2461 {
2466 else
2469 }
2472 }
2473 }
2476 {
2479 {
2481 {
2485 else
2487 }
2488 else
2489 {
2494 else
2497 }
2500 }
2501 }
2504 error_count
2507 }
2509 }
2511 int
2513 {
2515 }
2517 /* Call __cxa_bad_array_new_length to indicate that the size calculation
2518 overflowed. Pretend it returns sizetype so that it plays nicely in the
2519 COND_EXPR. */
2521 tree
2523 {
2525 {
2530 fn = push_throw_library_fn
2532 }
2535 }
2537 /* Attempt to find the initializer for flexible array field T in the
2538 initializer INIT, when non-null. Returns the initializer when
2539 successful and NULL otherwise. */
2540 static tree
2542 {
2549 /* Iterate over all top-level initializer elements. */
2551 /* If the member T is found, return it. */
2556 }
2558 /* Attempt to verify that the argument, OPER, of a placement new expression
2559 refers to an object sufficiently large for an object of TYPE or an array
2560 of NELTS of such objects when NELTS is non-null, and issue a warning when
2561 it does not. SIZE specifies the size needed to construct the object or
2562 array and captures the result of NELTS * sizeof (TYPE). (SIZE could be
2563 greater when the array under construction requires a cookie to store
2564 NELTS. GCC's placement new expression stores the cookie when invoking
2565 a user-defined placement new operator function but not the default one.
2566 Placement new expressions with user-defined placement new operator are
2567 not diagnosed since we don't know how they use the buffer (this could
2568 be a future extension). */
2569 static void
2571 {
2574 /* The number of bytes to add to or subtract from the size of the provided
2575 buffer based on an offset into an array or an array element reference.
2576 Although intermediate results may be negative (as in a[3] - 2) a valid
2577 final result cannot be. */
2579 /* True when the size of the entire destination object should be used
2580 to compute the possibly optimistic estimate of the available space. */
2582 /* True when the reference to the destination buffer is an ADDR_EXPR. */
2587 /* Using a function argument or a (non-array) variable as an argument
2588 to placement new is not checked since it's unknown what it might
2589 point to. */
2595 /* Evaluate any constant expressions. */
2598 /* Handle the common case of array + offset expression when the offset
2599 is a constant. */
2601 {
2602 /* If the offset is compile-time constant, use it to compute a more
2603 accurate estimate of the size of the buffer. Since the operand
2604 of POINTER_PLUS_EXPR is represented as an unsigned type, convert
2605 it to signed first.
2606 Otherwise, use the size of the entire array as an optimistic
2607 estimate (this may lead to false negatives). */
2611 else
2617 }
2622 {
2625 }
2631 {
2632 /* Similar to the offset computed above, see if the array index
2633 is a compile-time constant. If so, and unless the offset was
2634 not a compile-time constant, use the index to determine the
2635 size of the buffer. Otherwise, use the entire array as
2636 an optimistic estimate of the size. */
2640 else
2641 {
2644 }
2647 }
2649 /* Refers to the declared object that constains the subobject referenced
2650 by OPER. When the object is initialized, makes it possible to determine
2651 the actual size of a flexible array member used as the buffer passed
2652 as OPER to placement new. */
2654 /* True when operand is a COMPONENT_REF, to distinguish flexible array
2655 members from arrays of unspecified size. */
2658 /* For COMPONENT_REF (i.e., a struct member) the size of the entire
2659 enclosing struct. Used to validate the adjustment (offset) into
2660 an array at the end of a struct. */
2663 /* Descend into a struct or union to find the member whose address
2664 is being used as the argument. */
2666 {
2675 }
2682 {
2683 /* A possibly optimistic estimate of the number of bytes available
2684 in the destination buffer. */
2686 /* True when the estimate above is in fact the exact size
2687 of the destination buffer rather than an estimate. */
2690 /* Treat members of unions and members of structs uniformly, even
2691 though the size of a member of a union may be viewed as extending
2692 to the end of the union itself (it is by __builtin_object_size). */
2696 {
2697 /* Use the size of the entire array object when the expression
2698 refers to a variable or its size depends on an expression
2699 that's not a compile-time constant. */
2702 }
2704 {
2705 /* Use the size of the type of the destination buffer object
2706 as the optimistic estimate of the available space in it.
2707 Use the maximum possible size for zero-size arrays and
2708 flexible array members (except of initialized objects
2709 thereof). */
2712 }
2715 {
2717 {
2718 /* Constructing into a buffer provided by the flexible array
2719 member of a declared object (which is permitted as a G++
2720 extension). If the array member has been initialized,
2721 determine its size from the initializer. Otherwise,
2722 the array size is zero. */
2726 }
2727 else
2730 }
2735 {
2740 && !var_decl
2743 }
2745 /* Reduce the size of the buffer by the adjustment computed above
2746 from the offset and/or the index into the array. */
2749 else
2750 {
2754 {
2758 }
2759 }
2761 /* The minimum amount of space needed for the allocation. This
2762 is an optimistic estimate that makes it possible to detect
2763 placement new invocation for some undersize buffers but not
2764 others. */
2765 offset_int bytes_need;
2774 else
2775 {
2776 /* The type is a VLA. */
2778 }
2781 {
2785 exact_size ?
2786 "placement new constructing an object of type "
2787 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2788 "and size %qwi"
2790 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2794 else
2796 exact_size ?
2797 "placement new constructing an array of objects "
2798 "of type %qT and size %qwu in a region of type %qT "
2799 "and size %qwi"
2801 "of type %qT and size %qwu in a region of type %qT "
2805 else
2807 exact_size ?
2808 "placement new constructing an object of type %qT "
2809 "and size %qwu in a region of type %qT and size %qwi"
2811 "and size %qwu in a region of type %qT and size "
2815 }
2816 }
2817 }
2819 /* True if alignof(T) > __STDCPP_DEFAULT_NEW_ALIGNMENT__. */
2821 bool
2823 {
2826 }
2828 /* Return the alignment we expect malloc to guarantee. This should just be
2829 MALLOC_ABI_ALIGNMENT, but that macro defaults to only BITS_PER_WORD for some
2830 reason, so don't let the threshold be smaller than max_align_t_align. */
2832 unsigned
2834 {
2836 }
2838 /* Determine whether an allocation function is a namespace-scope
2839 non-replaceable placement new function. See DR 1748.
2840 TODO: Enable in all standard modes. */
2841 static bool
2843 {
2845 {
2850 }
2852 }
2854 /* Generate code for a new-expression, including calling the "operator
2855 new" function, initializing the object, and, if an exception occurs
2856 during construction, cleaning up. The arguments are as for
2857 build_raw_new_expr. This may change PLACEMENT and INIT.
2858 TYPE is the type of the object being constructed, possibly an array
2859 of NELTS elements when NELTS is non-null (in "new T[NELTS]", T may
2860 be an array of the form U[inner], with the whole expression being
2861 "new U[NELTS][inner]"). */
2863 static tree
2866 tsubst_flags_t complain)
2867 {
2869 /* True iff this is a call to "operator new[]" instead of just
2870 "operator new". */
2872 /* If ARRAY_P is true, the element type of the array. This is never
2873 an ARRAY_TYPE; for something like "new int[3][4]", the
2874 ELT_TYPE is "int". If ARRAY_P is false, this is the same type as
2875 TYPE. */
2876 tree elt_type;
2877 /* The type of the new-expression. (This type is always a pointer
2878 type.) */
2879 tree pointer_type;
2880 tree non_const_pointer_type;
2881 /* The most significant array bound in int[OUTER_NELTS][inner]. */
2883 /* For arrays with a non-constant number of elements, a bounds checks
2884 on the NELTS parameter to avoid integer overflow at runtime. */
2887 /* Number of the "inner" elements in "new T[OUTER_NELTS][inner]". */
2890 /* Size of the inner array elements (those with constant dimensions). */
2891 offset_int inner_size;
2892 /* The address returned by the call to "operator new". This node is
2893 a VAR_DECL and is therefore reusable. */
2894 tree alloc_node;
2895 tree alloc_fn;
2898 /* If non-NULL, the number of extra bytes to allocate at the
2899 beginning of the storage allocated for an array-new expression in
2900 order to store the number of elements. */
2902 tree placement_first;
2904 /* True if the function we are calling is a placement allocation
2905 function. */
2907 /* True if the storage must be initialized, either by a constructor
2908 or due to an explicit new-initializer. */
2910 /* The address of the thing allocated, not including any cookie. In
2911 particular, if an array cookie is in use, DATA_ADDR is the
2912 address of the first array element. This node is a VAR_DECL, and
2913 is therefore reusable. */
2914 tree data_addr;
2919 {
2922 }
2924 {
2925 /* Transforms new (T[N]) to new T[N]. The former is a GNU
2926 extension for variable N. (This also covers new T where T is
2927 a VLA typedef.) */
2933 }
2935 /* Lots of logic below depends on whether we have a constant number of
2936 elements, so go ahead and fold it now. */
2939 /* If our base type is an array, then make sure we know how many elements
2940 it has. */
2944 {
2948 {
2953 {
2957 }
2959 }
2960 else
2961 {
2963 {
2967 }
2969 }
2973 inner_nelts_cst,
2974 complain);
2975 }
2978 {
2981 }
2986 /* Warn if we performed the (T[N]) to T[N] transformation and N is
2987 variable. */
2990 {
2992 {
2999 }
3000 else
3002 }
3005 {
3009 }
3013 "%<new%> of initializer_list does not "
3022 {
3024 /* A program that calls for default-initialization [...] of an
3025 entity of reference type is ill-formed. */
3029 /* A new-expression that creates an object of type T initializes
3030 that object as follows:
3031 - If the new-initializer is omitted:
3032 -- If T is a (possibly cv-qualified) non-POD class type
3033 (or array thereof), the object is default-initialized (8.5).
3034 [...]
3035 -- Otherwise, the object created has indeterminate
3036 value. If T is a const-qualified type, or a (possibly
3037 cv-qualified) POD class type (or array thereof)
3038 containing (directly or indirectly) a member of
3039 const-qualified type, the program is ill-formed; */
3049 }
3053 {
3057 }
3061 {
3062 /* Maximum available size in bytes. Half of the address space
3063 minus the cookie size. */
3064 offset_int max_size
3066 /* Maximum number of outer elements which can be allocated. */
3067 offset_int max_outer_nelts;
3068 tree max_outer_nelts_tree;
3074 /* Unconditionally subtract the cookie size. This decreases the
3075 maximum object size and is safe even if we choose not to use
3076 a cookie after all. */
3082 {
3086 }
3094 {
3096 {
3097 /* When the array size is constant, check it at compile time
3098 to make sure it doesn't exceed the implementation-defined
3099 maximum, as required by C++ 14 (in C++ 11 this requirement
3100 isn't explicitly stated but it's enforced anyway -- see
3101 grokdeclarator in cp/decl.c). */
3105 }
3106 }
3107 else
3108 {
3109 /* When a runtime check is necessary because the array size
3110 isn't constant, keep only the top-most seven bits (starting
3111 with the most significant non-zero bit) of the maximum size
3112 to compare the array size against, to simplify encoding the
3113 constant maximum size in the instruction stream. */
3120 outer_nelts,
3121 max_outer_nelts_tree);
3122 }
3123 }
3131 /* If PLACEMENT is a single simple pointer type not passed by
3132 reference, prepare to capture it in a temporary variable. Do
3133 this now, since PLACEMENT will change in the calls below. */
3141 /* Allocate the object. */
3142 tree fnname;
3143 tree fns;
3147 member_new_p = !globally_qualified_p
3149 && (array_p
3154 {
3155 /* Use a class-specific operator new. */
3156 /* If a cookie is required, add some extra space. */
3159 else
3160 {
3162 /* No size arithmetic necessary, so the size check is
3163 not needed. */
3166 }
3167 /* Perform the overflow check. */
3174 /* Create the argument list. */
3176 /* Do name-lookup to find the appropriate operator. */
3179 {
3183 }
3185 {
3187 {
3190 }
3192 }
3196 {
3199 alloc_call
3203 /* If no matching function is found and the allocated object type
3204 has new-extended alignment, the alignment argument is removed
3205 from the argument list, and overload resolution is performed
3206 again. */
3209 }
3213 LOOKUP_NORMAL,
3215 }
3216 else
3217 {
3218 /* Use a global operator new. */
3219 /* See if a cookie might be required. */
3221 {
3223 /* No size arithmetic necessary, so the size check is
3224 not needed. */
3227 }
3233 }
3240 /* Now, check to see if this function is actually a placement
3241 allocation function. This can happen even when PLACEMENT is NULL
3242 because we might have something like:
3244 struct S { void* operator new (size_t, int i = 0); };
3246 A call to `new S' will get this allocation function, even though
3247 there is no explicit placement argument. If there is more than
3248 one argument, or there are variable arguments, then this is a
3249 placement allocation function. */
3250 placement_allocation_fn_p
3255 && !placement_allocation_fn_p
3260 {
3261 auto_diagnostic_group d;
3264 {
3270 }
3271 }
3273 /* If we found a simple case of PLACEMENT_EXPR above, then copy it
3274 into a temporary variable. */
3280 {
3286 {
3290 }
3294 {
3295 /* Attempt to make the warning point at the operator new argument. */
3300 }
3301 }
3303 /* In the simple case, we can stop now. */
3308 /* Store the result of the allocation call in a variable so that we can
3309 use it more than once. */
3313 /* Strip any COMPOUND_EXPRs from ALLOC_CALL. */
3317 /* Preevaluate the placement args so that we don't reevaluate them for a
3318 placement delete. */
3320 {
3321 tree inits;
3325 alloc_expr);
3326 }
3328 /* unless an allocation function is declared with an empty excep-
3329 tion-specification (_except.spec_), throw(), it indicates failure to
3330 allocate storage by throwing a bad_alloc exception (clause _except_,
3331 _lib.bad.alloc_); it returns a non-null pointer otherwise If the allo-
3332 cation function is declared with an empty exception-specification,
3333 throw(), it returns null to indicate failure to allocate storage and a
3334 non-null pointer otherwise.
3336 So check for a null exception spec on the op new we just called. */
3339 check_new
3343 {
3344 tree cookie;
3345 tree cookie_ptr;
3346 tree size_ptr_type;
3348 /* Adjust so we're pointing to the start of the object. */
3351 /* Store the number of bytes allocated so that we can know how
3352 many elements to destroy later. We use the last sizeof
3353 (size_t) bytes to store the number of elements. */
3364 {
3365 /* Also store the element size. */
3376 }
3377 }
3378 else
3379 {
3382 }
3384 /* Now use a pointer to the type we've actually allocated. */
3386 /* But we want to operate on a non-const version to start with,
3387 since we'll be modifying the elements. */
3388 non_const_pointer_type = build_pointer_type
3392 /* Any further uses of alloc_node will want this type, too. */
3395 /* Now initialize the allocated object. Note that we preevaluate the
3396 initialization expression, apart from the actual constructor call or
3397 assignment--we do this because we want to delay the allocation as long
3398 as possible in order to minimize the size of the exception region for
3399 placement delete. */
3401 {
3406 {
3409 }
3412 {
3413 /* build_value_init doesn't work in templates, and we don't need
3414 the initializer anyway since we're going to throw it away and
3415 rebuild it at instantiation time, so just build up a single
3416 constructor call to get any appropriate diagnostics. */
3420 complete_ctor_identifier,
3422 LOOKUP_NORMAL,
3423 complain);
3425 }
3427 {
3431 {
3435 else
3436 {
3440 complain);
3441 else
3442 /* We'll check the length at runtime. */
3446 }
3447 }
3449 {
3453 }
3454 init_expr
3458 integer_one_node,
3459 complain),
3460 vecinit,
3461 explicit_value_init_p,
3463 complain);
3465 /* An array initialization is stable because the initialization
3466 of each element is a full-expression, so the temporaries don't
3467 leak out. */
3469 }
3470 else
3471 {
3475 {
3477 complete_ctor_identifier,
3479 LOOKUP_NORMAL,
3480 complain);
3481 }
3483 {
3484 /* Something like `new int()'. NO_CLEANUP is needed so
3485 we don't try and build a (possibly ill-formed)
3486 destructor. */
3491 }
3492 else
3493 {
3494 tree ie;
3496 /* We are processing something like `new int (10)', which
3497 means allocate an int, and initialize it with 10. */
3500 complain);
3503 }
3504 /* If the initializer uses C++14 aggregate NSDMI that refer to the
3505 object being initialized, replace them now and don't try to
3506 preevaluate. */
3514 stable = (!had_placeholder
3516 }
3521 /* If any part of the object initialization terminates by throwing an
3522 exception and a suitable deallocation function can be found, the
3523 deallocation function is called to free the memory in which the
3524 object was being constructed, after which the exception continues
3525 to propagate in the context of the new-expression. If no
3526 unambiguous matching deallocation function can be found,
3527 propagating the exception does not cause the object's memory to be
3528 freed. */
3530 {
3532 tree cleanup;
3534 /* The Standard is unclear here, but the right thing to do
3535 is to use the same method for finding deallocation
3536 functions that we use for finding allocation functions. */
3537 cleanup = (build_op_delete_call
3539 alloc_node,
3540 size,
3541 globally_qualified_p,
3543 alloc_fn,
3544 complain));
3549 /* This is much simpler if we were able to preevaluate all of
3550 the arguments to the constructor call. */
3551 {
3552 /* CLEANUP is compiler-generated, so no diagnostics. */
3556 /* Likewise, this try-catch is compiler-generated. */
3558 }
3559 else
3560 /* Ack! First we allocate the memory. Then we set our sentry
3561 variable to true, and expand a cleanup that deletes the
3562 memory if sentry is true. Then we run the constructor, and
3563 finally clear the sentry.
3565 We need to do this because we allocate the space first, so
3566 if there are any temporaries with cleanups in the
3567 constructor args and we weren't able to preevaluate them, we
3568 need this EH region to extend until end of full-expression
3569 to preserve nesting. */
3570 {
3578 /* CLEANUP is compiler-generated, so no diagnostics. */
3588 init_expr
3591 end));
3592 /* Likewise, this is compiler-generated. */
3594 }
3595 }
3596 }
3597 else
3600 /* Now build up the return value in reverse order. */
3610 /* If we don't have an initializer or a cookie, strip the TARGET_EXPR
3611 and return the call (which doesn't need to be adjusted). */
3613 else
3614 {
3616 {
3619 nullptr_node,
3620 complain);
3623 }
3625 /* Perform the allocation before anything else, so that ALLOC_NODE
3626 has been initialized before we start using it. */
3628 }
3633 /* A new-expression is never an lvalue. */
3637 }
3639 /* Generate a representation for a C++ "new" expression. *PLACEMENT
3640 is a vector of placement-new arguments (or NULL if none). If NELTS
3641 is NULL, TYPE is the type of the storage to be allocated. If NELTS
3642 is not NULL, then this is an array-new allocation; TYPE is the type
3643 of the elements in the array and NELTS is the number of elements in
3644 the array. *INIT, if non-NULL, is the initializer for the new
3645 object, or an empty vector to indicate an initializer of "()". If
3646 USE_GLOBAL_NEW is true, then the user explicitly wrote "::new"
3647 rather than just "new". This may change PLACEMENT and INIT. */
3649 tree
3652 {
3653 tree rval;
3662 /* Don't do auto deduction where it might affect mangling. */
3664 {
3667 {
3670 /* E.g. new auto(x) must have exactly one element, or
3671 a {} initializer will have one element. */
3673 {
3676 }
3677 /* For the rest, e.g. new A(1, 2, 3), create a list. */
3679 {
3681 tree t;
3684 {
3688 }
3689 }
3691 }
3692 }
3695 {
3702 use_global_new);
3707 {
3709 /* Also copy any CONSTRUCTORs in *init, since reshape_init and
3710 digest_init clobber them in place. */
3712 {
3716 }
3717 }
3723 }
3726 {
3728 {
3731 else
3733 }
3735 /* Try to determine the constant value only for the purposes
3736 of the diagnostic below but continue to use the original
3737 value and handle const folding later. */
3740 /* The expression in a noptr-new-declarator is erroneous if it's of
3741 non-class type and its value before converting to std::size_t is
3742 less than zero. ... If the expression is a constant expression,
3743 the program is ill-fomed. */
3746 {
3750 }
3754 }
3756 /* ``A reference cannot be created by the new operator. A reference
3757 is not an object (8.2.2, 8.4.3), so a pointer to it could not be
3758 returned by new.'' ARM 5.3.3 */
3760 {
3763 else
3766 }
3769 {
3773 }
3775 /* The type allocated must be complete. If the new-type-id was
3776 "T[N]" then we are just checking that "T" is complete here, but
3777 that is equivalent, since the value of "N" doesn't matter. */
3786 {
3792 }
3794 /* Wrap it in a NOP_EXPR so warn_if_unused_value doesn't complain. */
3799 }
3800 \f
3801 static tree
3803 special_function_kind auto_delete_vec,
3805 {
3806 tree virtual_size;
3808 tree size_exp;
3810 /* Temporary variables used by the loop. */
3813 /* This is the body of the loop that implements the deletion of a
3814 single element, and moves temp variables to next elements. */
3815 tree body;
3817 /* This is the LOOP_EXPR that governs the deletion of the elements. */
3820 /* This is the thing that governs what to do after the loop has run. */
3823 /* This is the BIND_EXPR which holds the outermost iterator of the
3824 loop. It is convenient to set this variable up and test it before
3825 executing any other code in the loop.
3826 This is also the containing expression returned by this function. */
3828 tree tmp;
3830 /* We should only have 1-D arrays here. */
3837 {
3839 {
3840 auto_diagnostic_group d;
3842 "possible problem detected in invocation of "
3844 {
3847 "class-specific operator delete [] will be called, "
3849 }
3850 }
3851 /* This size won't actually be used. */
3854 }
3861 {
3862 /* Make sure the destructor is callable. */
3864 {
3867 complain);
3870 }
3872 }
3874 /* The below is short by the cookie size. */
3879 tbase_init
3883 base),
3884 virtual_size),
3885 complain);
3903 complain);
3911 no_destructor:
3912 /* Delete the storage if appropriate. */
3914 {
3915 tree base_tbd;
3917 /* The below is short by the cookie size. */
3922 /* no header */
3924 else
3925 {
3926 tree cookie_size;
3930 MINUS_EXPR,
3933 cookie_size,
3934 complain);
3938 /* True size with header. */
3940 }
3947 complain);
3948 }
3952 ;
3955 else
3956 /* The delete operator mist be called, even if a destructor
3957 throws. */
3963 /* Outermost wrapper: If pointer is null, punt. */
3966 /* This is a compiler generated comparison, don't emit
3967 e.g. -Wnonnull-compare warning for it. */
3975 {
3978 }
3981 /* Pre-evaluate the SAVE_EXPR outside of the BIND_EXPR. */
3985 }
3987 /* Create an unnamed variable of the indicated TYPE. */
3989 tree
3991 {
3992 tree decl;
4002 }
4004 /* Create a new temporary variable of the indicated TYPE, initialized
4005 to INIT.
4007 It is not entered into current_binding_level, because that breaks
4008 things when it comes time to do final cleanups (which take place
4009 "outside" the binding contour of the function). */
4011 tree
4013 {
4014 tree decl;
4023 }
4025 /* Subroutine of build_vec_init. Returns true if assigning to an array of
4026 INNER_ELT_TYPE from INIT is trivial. */
4028 static bool
4030 {
4035 }
4037 /* Subroutine of build_vec_init: Check that the array has at least N
4038 elements. Other parameters are local variables in build_vec_init. */
4040 void
4042 {
4045 {
4047 {
4049 nelts);
4053 }
4054 /* Don't check an array new when -fno-exceptions. */
4055 }
4058 {
4059 /* Make sure the last element of the initializer is in bounds. */
4060 finish_expr_stmt
4061 (ubsan_instrument_bounds
4063 }
4064 }
4066 /* `build_vec_init' returns tree structure that performs
4067 initialization of a vector of aggregate types.
4069 BASE is a reference to the vector, of ARRAY_TYPE, or a pointer
4070 to the first element, of POINTER_TYPE.
4071 MAXINDEX is the maximum index of the array (one less than the
4072 number of elements). It is only used if BASE is a pointer or
4073 TYPE_DOMAIN (TREE_TYPE (BASE)) == NULL_TREE.
4075 INIT is the (possibly NULL) initializer.
4077 If EXPLICIT_VALUE_INIT_P is true, then INIT must be NULL. All
4078 elements in the array are value-initialized.
4080 FROM_ARRAY is 0 if we should init everything with INIT
4081 (i.e., every element initialized from INIT).
4082 FROM_ARRAY is 1 if we should index into INIT in parallel
4083 with initialization of DECL.
4084 FROM_ARRAY is 2 if we should index into INIT in parallel,
4085 but use assignment instead of initialization. */
4087 tree
4091 {
4092 tree rval;
4095 tree iterator;
4096 /* The type of BASE. */
4098 /* The type of an element in the array. */
4100 /* The element type reached after removing all outer array
4101 types. */
4102 tree inner_elt_type;
4103 /* The type of a pointer to an element in the array. */
4104 tree ptype;
4105 tree stmt_expr;
4106 tree compound_stmt;
4129 /* Look through the TARGET_EXPR around a compound literal. */
4138 {
4141 {
4144 }
4145 }
4147 /* If we have a braced-init-list or string constant, make sure that the array
4148 is big enough for all the initializers. */
4163 || (same_type_ignoring_top_level_qualifiers_p
4165 /* Don't do this if the CONSTRUCTOR might contain something
4166 that might throw and require us to clean up. */
4170 {
4171 /* Do non-default initialization of trivial arrays resulting from
4172 brace-enclosed initializers. In this case, digest_init and
4173 store_constructor will handle the semantics for us. */
4179 }
4185 {
4191 }
4192 else
4195 /* The code we are generating looks like:
4196 ({
4197 T* t1 = (T*) base;
4198 T* rval = t1;
4199 ptrdiff_t iterator = maxindex;
4200 try {
4201 for (; iterator != -1; --iterator) {
4202 ... initialize *t1 ...
4203 ++t1;
4204 }
4205 } catch (...) {
4206 ... destroy elements that were constructed ...
4207 }
4208 rval;
4209 })
4211 We can omit the try and catch blocks if we know that the
4212 initialization will never throw an exception, or if the array
4213 elements do not have destructors. We can omit the loop completely if
4214 the elements of the array do not have constructors.
4216 We actually wrap the entire body of the above in a STMT_EXPR, for
4217 tidiness.
4219 When copying from array to another, when the array elements have
4220 only trivial copy constructors, we should use __builtin_memcpy
4221 rather than generating a loop. That way, we could take advantage
4222 of whatever cleverness the back end has for dealing with copies
4223 of blocks of memory. */
4232 /* If initializing one array from another, initialize element by
4233 element. We rely upon the below calls to do the argument
4234 checking. Evaluate the initializer before entering the try block. */
4236 {
4245 }
4247 /* Protect the entire array initialization so that we can destroy
4248 the partially constructed array if an exception is thrown.
4249 But don't do this if we're assigning. */
4252 {
4254 }
4256 /* Should we try to create a constant initializer? */
4260 : (type_has_constexpr_default_constructor
4266 /* If we're initializing a static array, we want to do static
4267 initialization of any elements with constant initializers even if
4268 some are non-constant. */
4274 /* Skip over the handling of non-empty init lists. */
4277 /* Maybe pull out constant value when from_array? */
4280 {
4281 /* Do non-default initialization of non-trivial arrays resulting from
4282 brace-enclosed initializers. */
4285 /* If the constructor already has the array type, it's been through
4286 digest_init, so we shouldn't try to do anything more. */
4297 {
4299 tree one_init;
4301 num_initialized_elts++;
4308 else
4314 {
4317 {
4321 else
4323 }
4324 else
4325 {
4327 {
4332 }
4334 }
4335 }
4342 complain);
4345 else
4349 complain);
4352 else
4354 }
4356 /* Any elements without explicit initializers get T{}. */
4358 }
4360 {
4361 /* Check that the array is at least as long as the string. */
4368 /* Copy the string to the first part of the array. */
4374 /* Adjust the counter and pointer. */
4383 /* And set the rest of the array to NUL. */
4386 }
4388 {
4393 {
4397 }
4398 }
4400 /* Now, default-initialize any remaining elements. We don't need to
4401 do that if a) the type does not need constructing, or b) we've
4402 already initialized all the elements.
4404 We do need to keep going if we're copying an array. */
4407 /* With a constexpr default constructor, which we checked for when
4408 setting try_const above, default-initialization is equivalent to
4409 value-initialization, and build_value_init gives us something more
4410 friendly to maybe_constant_init. */
4415 && (num_initialized_elts
4417 {
4418 /* If the ITERATOR is lesser or equal to -1, then we don't have to loop;
4419 we've already initialized all the elements. */
4420 tree for_stmt;
4421 tree elt_init;
4422 tree to;
4430 complain);
4437 /* If the initializer is {}, then all elements are initialized from T{}.
4438 But for non-classes, that's the same as value-initialization. */
4440 {
4442 {
4444 }
4445 else
4446 {
4449 }
4450 }
4453 {
4454 tree from;
4457 {
4463 }
4464 else
4477 complain);
4478 else
4480 }
4482 {
4484 {
4489 }
4490 else
4493 explicit_value_init_p,
4495 }
4497 {
4501 }
4502 else
4503 {
4507 else
4508 {
4511 complain);
4513 ? error_mark_node
4515 }
4516 }
4522 {
4523 /* FIXME refs to earlier elts */
4526 {
4528 /* Don't fill the CONSTRUCTOR with zeros. */
4532 }
4533 else
4534 {
4538 else
4540 }
4543 {
4546 {
4549 }
4550 }
4551 }
4559 complain));
4562 complain));
4565 }
4567 /* Make sure to cleanup any partially constructed elements. */
4570 {
4571 tree e;
4574 complain);
4576 /* Flatten multi-dimensional array since build_vec_delete only
4577 expects one-dimensional array. */
4581 /* Avoid mixing signed and unsigned. */
4584 complain);
4593 }
4595 /* The value of the array initialization is the array itself, RVAL
4596 is a pointer to the first element. */
4607 {
4609 {
4612 }
4615 else
4617 }
4619 /* Now make the result have the correct type. */
4621 {
4626 }
4629 }
4631 /* Call the DTOR_KIND destructor for EXP. FLAGS are as for
4632 build_delete. */
4634 static tree
4636 tsubst_flags_t complain)
4637 {
4638 tree name;
4640 {
4655 }
4660 flags,
4661 complain);
4662 }
4664 /* Generate a call to a destructor. TYPE is the type to cast ADDR to.
4665 ADDR is an expression which yields the store to be destroyed.
4666 AUTO_DELETE is the name of the destructor to call, i.e., either
4667 sfk_complete_destructor, sfk_base_destructor, or
4668 sfk_deleting_destructor.
4670 FLAGS is the logical disjunction of zero or more LOOKUP_
4671 flags. See cp-tree.h for more info. */
4673 tree
4676 {
4677 tree expr;
4684 /* Can happen when CURRENT_EXCEPTION_OBJECT gets its type
4685 set to `error_mark_node' before it gets properly cleaned up. */
4693 {
4695 {
4699 }
4702 }
4708 {
4711 /* We don't want to warn about delete of void*, only other
4712 incomplete types. Deleting other incomplete types
4713 invokes undefined behavior, but it is not ill-formed, so
4714 compile to something that would even do The Right Thing
4715 (TM) should the type have a trivial dtor and no delete
4716 operator. */
4718 {
4721 {
4723 {
4724 auto_diagnostic_group d;
4726 "possible problem detected in invocation of "
4728 {
4731 "neither the destructor nor the class-specific "
4732 "operator delete will be called, even if they "
4734 }
4735 }
4736 }
4740 {
4743 {
4746 "deleting object of abstract class type %qT"
4747 " which has non-virtual destructor"
4749 else
4751 "deleting object of polymorphic class type %qT"
4752 " which has non-virtual destructor"
4754 }
4755 }
4756 }
4758 /* Throw away const and volatile on target type of addr. */
4760 }
4761 else
4762 {
4763 /* Don't check PROTECT here; leave that decision to the
4764 destructor. If the destructor is accessible, call it,
4765 else report error. */
4771 }
4774 /* We will use ADDR multiple times so we must save it. */
4779 {
4783 }
4789 {
4790 /* Leave do_delete null. */
4791 }
4792 /* For `::delete x', we must not use the deleting destructor
4793 since then we would not be sure to get the global `operator
4794 delete'. */
4796 {
4798 /* Delete the object. */
4800 head,
4805 complain);
4806 /* Otherwise, treat this like a complete object destructor
4807 call. */
4809 }
4810 /* If the destructor is non-virtual, there is no deleting
4811 variant. Instead, we must explicitly call the appropriate
4812 `operator delete' here. */
4814 {
4815 /* Build the call. */
4817 addr,
4822 complain);
4823 /* Call the complete object destructor. */
4825 }
4827 {
4828 /* Make sure we have access to the member op delete, even though
4829 we'll actually be calling it from the destructor. */
4834 complain);
4835 }
4840 else
4851 /* The delete operator must be called, regardless of whether
4852 the destructor throws.
4854 [expr.delete]/7 The deallocation function is called
4855 regardless of whether the destructor for the object or some
4856 element of the array throws an exception. */
4859 /* We need to calculate this before the dtor changes the vptr. */
4863 /* Handle deleting a null pointer. */
4871 /* This is a compiler generated comparison, don't emit
4872 e.g. -Wnonnull-compare warning for it. */
4880 }
4882 /* At the beginning of a destructor, push cleanups that will call the
4883 destructors for our base classes and members.
4885 Called from begin_destructor_body. */
4887 void
4889 {
4892 tree member;
4893 tree expr;
4896 /* Run destructors for all virtual baseclasses. */
4899 {
4900 tree cond = (condition_conversion
4902 current_in_charge_parm,
4903 integer_two_node)));
4905 /* The CLASSTYPE_VBASECLASSES vector is in initialization
4906 order, which is also the right order for pushing cleanups. */
4909 {
4911 {
4913 base_dtor_identifier,
4914 NULL,
4915 base_binfo,
4916 (LOOKUP_NORMAL
4918 tf_warning_or_error);
4920 {
4924 }
4925 }
4926 }
4927 }
4929 /* Take care of the remaining baseclasses. */
4932 {
4938 base_dtor_identifier,
4941 tf_warning_or_error);
4944 }
4946 /* Don't automatically destroy union members. */
4952 {
4961 {
4962 tree this_member = (build_class_member_access_expr
4966 tf_warning_or_error));
4968 sfk_complete_destructor,
4973 }
4974 }
4975 }
4977 /* Build a C++ vector delete expression.
4978 MAXINDEX is the number of elements to be deleted.
4979 ELT_SIZE is the nominal size of each element in the vector.
4980 BASE is the expression that should yield the store to be deleted.
4981 This function expands (or synthesizes) these calls itself.
4982 AUTO_DELETE_VEC says whether the container (vector) should be deallocated.
4984 This also calls delete for virtual baseclasses of elements of the vector.
4986 Update: MAXINDEX is no longer needed. The size can be extracted from the
4987 start of the vector for pointers, and from the type for arrays. We still
4988 use MAXINDEX for arrays because it happens to already have one of the
4989 values we'd have to extract. (We could use MAXINDEX with pointers to
4990 confirm the size, and trap if the numbers differ; not clear that it'd
4991 be worth bothering.) */
4993 tree
4995 special_function_kind auto_delete_vec,
4997 {
4998 tree type;
4999 tree rval;
5005 {
5006 /* Step back one from start of vector, and read dimension. */
5007 tree cookie_addr;
5012 {
5015 }
5020 cookie_addr);
5022 }
5024 {
5025 /* Get the total number of things in the array, maxindex is a
5026 bad name. */
5033 {
5036 }
5037 }
5038 else
5039 {
5043 }
5051 }