| blob | b4b5e0acd45e7a8c81ab6ba7486973aa65ca5703 |
1 /* Handle initialization things in C++.
2 Copyright (C) 1987-2016 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. */
48 /* We are about to generate some complex initialization code.
49 Conceptually, it is all a single expression. However, we may want
50 to include conditionals, loops, and other such statement-level
51 constructs. Therefore, we build the initialization code inside a
52 statement-expression. This function starts such an expression.
53 STMT_EXPR_P and COMPOUND_STMT_P are filled in by this function;
54 pass them back to finish_init_stmts when the expression is
55 complete. */
57 static bool
59 {
66 }
68 /* Finish out the statement-expression begun by the previous call to
69 begin_init_stmts. Returns the statement-expression itself. */
71 static tree
73 {
81 }
83 /* Constructors */
85 /* Called from initialize_vtbl_ptrs via dfs_walk. BINFO is the base
86 which we want to initialize the vtable pointer for, DATA is
87 TREE_LIST whose TREE_VALUE is the this ptr expression. */
89 static tree
91 {
96 {
100 tf_warning_or_error);
103 }
106 }
108 /* Initialize all the vtable pointers in the object pointed to by
109 ADDR. */
111 void
113 {
114 tree list;
115 tree type;
120 /* Walk through the hierarchy, initializing the vptr in each base
121 class. We do these in pre-order because we can't find the virtual
122 bases for a class until we've initialized the vtbl for that
123 class. */
125 }
127 /* Return an expression for the zero-initialization of an object with
128 type T. This expression will either be a constant (in the case
129 that T is a scalar), or a CONSTRUCTOR (in the case that T is an
130 aggregate), or NULL (in the case that T does not require
131 initialization). In either case, the value can be used as
132 DECL_INITIAL for a decl of the indicated TYPE; it is a valid static
133 initializer. If NELTS is non-NULL, and TYPE is an ARRAY_TYPE, NELTS
134 is the number of elements in the array. If STATIC_STORAGE_P is
135 TRUE, initializers are only generated for entities for which
136 zero-initialization does not simply mean filling the storage with
137 zero bytes. FIELD_SIZE, if non-NULL, is the bit size of the field,
138 subfields with bit positions at or above that bit size shouldn't
139 be added. Note that this only works when the result is assigned
140 to a base COMPONENT_REF; if we only have a pointer to the base subobject,
141 expand_assignment will end up clearing the full size of TYPE. */
143 static tree
145 tree field_size)
146 {
149 /* [dcl.init]
151 To zero-initialize an object of type T means:
153 -- if T is a scalar type, the storage is set to the value of zero
154 converted to T.
156 -- if T is a non-union class type, the storage for each nonstatic
157 data member and each base-class subobject is zero-initialized.
159 -- if T is a union type, the storage for its first data member is
160 zero-initialized.
162 -- if T is an array type, the storage for each element is
163 zero-initialized.
165 -- if T is a reference type, no initialization is performed. */
170 ;
172 /* In order to save space, we do not explicitly build initializers
173 for items that do not need them. GCC's semantics are that
174 items with static storage duration that are not otherwise
175 initialized are initialized to zero. */
176 ;
182 {
183 tree field;
186 /* Iterate over the fields, building initializations. */
188 {
195 /* Don't add virtual bases for base classes if they are beyond
196 the size of the current field, that means it is present
197 somewhere else in the object. */
199 {
204 }
206 /* Note that for class types there will be FIELD_DECLs
207 corresponding to base classes as well. Thus, iterating
208 over TYPE_FIELDs will result in correct initialization of
209 all of the subobjects. */
211 {
212 tree new_field_size
219 static_storage_p,
220 new_field_size);
223 }
225 /* For unions, only the first field is initialized. */
228 }
230 /* Build a constructor to contain the initializations. */
232 }
234 {
235 tree max_index;
238 /* Iterate over the array elements, building initializations. */
243 else
246 /* If we have an error_mark here, we should just return error mark
247 as we don't know the size of the array yet. */
252 /* A zero-sized array, which is accepted as an extension, will
253 have an upper bound of -1. */
255 {
256 constructor_elt ce;
258 /* If this is a one element array, we just use a regular init. */
261 else
263 max_index);
269 {
272 }
273 }
275 /* Build a constructor to contain the initializations. */
277 }
280 else
283 /* In all cases, the initializer is a constant. */
288 }
290 /* Return an expression for the zero-initialization of an object with
291 type T. This expression will either be a constant (in the case
292 that T is a scalar), or a CONSTRUCTOR (in the case that T is an
293 aggregate), or NULL (in the case that T does not require
294 initialization). In either case, the value can be used as
295 DECL_INITIAL for a decl of the indicated TYPE; it is a valid static
296 initializer. If NELTS is non-NULL, and TYPE is an ARRAY_TYPE, NELTS
297 is the number of elements in the array. If STATIC_STORAGE_P is
298 TRUE, initializers are only generated for entities for which
299 zero-initialization does not simply mean filling the storage with
300 zero bytes. */
302 tree
304 {
306 }
308 /* Return a suitable initializer for value-initializing an object of type
309 TYPE, as described in [dcl.init]. */
311 tree
313 {
314 /* [dcl.init]
316 To value-initialize an object of type T means:
318 - if T is a class type (clause 9) with either no default constructor
319 (12.1) or a default constructor that is user-provided or deleted,
320 then the object is default-initialized;
322 - if T is a (possibly cv-qualified) class type without a user-provided
323 or deleted default constructor, then the object is zero-initialized
324 and the semantic constraints for default-initialization are checked,
325 and if T has a non-trivial default constructor, the object is
326 default-initialized;
328 - if T is an array type, then each element is value-initialized;
330 - otherwise, the object is zero-initialized.
332 A program that calls for default-initialization or
333 value-initialization of an entity of reference type is ill-formed. */
335 /* The AGGR_INIT_EXPR tweaking below breaks in templates. */
341 {
342 tree ctor =
345 complain);
355 {
356 /* This is a class that needs constructing, but doesn't have
357 a user-provided constructor. So we need to zero-initialize
358 the object and then call the implicitly defined ctor.
359 This will be handled in simplify_aggr_init_expr. */
362 }
363 }
365 /* Discard any access checking during subobject initialization;
366 the checks are implied by the call to the ctor which we have
367 verified is OK (cpp0x/defaulted46.C). */
372 }
374 /* Like build_value_init, but don't call the constructor for TYPE. Used
375 for base initializers. */
377 tree
379 {
381 {
385 }
386 /* FIXME the class and array cases should just use digest_init once it is
387 SFINAE-enabled. */
389 {
394 {
395 tree field;
398 /* Iterate over the fields, building initializations. */
400 {
411 /* We could skip vfields and fields of types with
412 user-defined constructors, but I think that won't improve
413 performance at all; it should be simpler in general just
414 to zero out the entire object than try to only zero the
415 bits that actually need it. */
417 /* Note that for class types there will be FIELD_DECLs
418 corresponding to base classes as well. Thus, iterating
419 over TYPE_FIELDs will result in correct initialization of
420 all of the subobjects. */
429 /* We shouldn't have gotten here for anything that would need
430 non-trivial initialization, and gimplify_init_ctor_preeval
431 would need to be fixed to allow it. */
434 }
436 /* Build a constructor to contain the zero- initializations. */
438 }
439 }
441 {
444 /* Iterate over the array elements, building initializations. */
447 /* If we have an error_mark here, we should just return error mark
448 as we don't know the size of the array yet. */
450 {
453 type);
455 }
458 /* A zero-sized array, which is accepted as an extension, will
459 have an upper bound of -1. */
461 {
462 constructor_elt ce;
464 /* If this is a one element array, we just use a regular init. */
467 else
478 /* We shouldn't have gotten here for anything that would need
479 non-trivial initialization, and gimplify_init_ctor_preeval
480 would need to be fixed to allow it. */
483 }
485 /* Build a constructor to contain the initializations. */
487 }
489 {
493 }
495 {
499 }
502 }
504 /* Initialize current class with INIT, a TREE_LIST of
505 arguments for a target constructor. If TREE_LIST is void_type_node,
506 an empty initializer list was given. */
508 static void
510 {
516 tf_warning_or_error));
518 {
520 LOOKUP_NORMAL
521 |LOOKUP_NONVIRTUAL
527 }
528 }
530 /* Return the non-static data initializer for FIELD_DECL MEMBER. */
532 tree
534 {
535 tree init;
540 {
541 /* Use a PLACEHOLDER_EXPR when we don't have a 'this' parameter to
542 refer to; constexpr evaluation knows what to do with it. */
545 }
548 {
553 /* Check recursive instantiation. */
555 {
559 }
560 else
561 {
564 /* Do deferred instantiation of the NSDMI. */
565 init = (tsubst_copy_and_build
572 }
573 }
574 else
575 {
578 {
579 unparsed:
584 }
585 /* Strip redundant TARGET_EXPR so we don't need to remap it, and
586 so the aggregate init code below will see a CONSTRUCTOR. */
592 /* Now put it back so C++17 copy elision works. */
594 }
598 }
600 /* Initialize MEMBER, a FIELD_DECL, with INIT, a TREE_LIST of
601 arguments. If TREE_LIST is void_type_node, an empty initializer
602 list was given; if NULL_TREE no initializer was given. */
604 static void
606 {
607 tree decl;
610 /* Use the non-static data member initializer if there was no
611 mem-initializer for this field. */
618 /* Effective C++ rule 12 requires that all data members be
619 initialized. */
623 member);
625 /* Get an lvalue for the data member. */
629 tf_warning_or_error);
635 {
637 /* Handle references. */
644 member);
645 }
648 {
649 /* mem() means value-initialization. */
651 {
655 }
656 else
657 {
663 }
664 }
665 /* Deal with this here, as we will get confused if we try to call the
666 assignment op for an anonymous union. This can happen in a
667 synthesized copy constructor. */
669 {
671 {
674 }
675 }
678 /* Pre-digested NSDMI. */
681 /* { } mem-initializer. */
686 {
687 /* With references and list-initialization, we need to deal with
688 extending temporary lifetimes. 12.2p5: "A temporary bound to a
689 reference member in a constructor’s ctor-initializer (12.6.2)
690 persists until the constructor exits." */
695 tf_warning_or_error);
697 {
702 }
705 /* A FIELD_DECL doesn't really have a suitable lifetime, but
706 make_temporary_var_for_ref_to_temp will treat it as automatic and
707 set_up_extended_ref_temp wants to use the decl in a warning. */
717 }
720 {
722 {
724 {
727 else
731 }
735 {
737 {
738 /* Initialize the array only if it's not a flexible
739 array member (i.e., if it has an upper bound). */
743 }
744 }
745 else
747 }
748 else
749 {
756 {
757 /* TYPE_NEEDS_CONSTRUCTING can be set just because we have a
758 vtable; still give this diagnostic. */
763 }
765 tf_warning_or_error));
766 }
767 }
768 else
769 {
771 {
772 tree core_type;
773 /* member traversal: note it leaves init NULL */
775 {
780 }
782 {
787 }
797 }
799 /* There was an explicit member initialization. Do some work
800 in that case. */
802 tf_warning_or_error);
807 tf_warning_or_error));
808 }
811 {
812 tree expr;
817 tf_warning_or_error);
820 tf_warning_or_error);
825 }
826 }
828 /* Returns a TREE_LIST containing (as the TREE_PURPOSE of each node) all
829 the FIELD_DECLs on the TYPE_FIELDS list for T, in reverse order. */
831 static tree
833 {
834 tree fields;
836 /* Note whether or not T is a union. */
841 {
842 tree fieldtype;
844 /* Skip CONST_DECLs for enumeration constants and so forth. */
850 /* For an anonymous struct or union, we must recursively
851 consider the fields of the anonymous type. They can be
852 directly initialized from the constructor. */
854 {
855 /* Add this field itself. Synthesized copy constructors
856 initialize the entire aggregate. */
858 /* And now add the fields in the anonymous aggregate. */
861 }
862 /* Add this field. */
865 }
868 }
870 /* Return the innermost aggregate scope for FIELD, whether that is
871 the enclosing class or an anonymous aggregate within it. */
873 static tree
875 {
878 else
880 }
882 /* The MEM_INITS are a TREE_LIST. The TREE_PURPOSE of each list gives
883 a FIELD_DECL or BINFO in T that needs initialization. The
884 TREE_VALUE gives the initializer, or list of initializer arguments.
886 Return a TREE_LIST containing all of the initializations required
887 for T, in the order in which they should be performed. The output
888 list has the same format as the input. */
890 static tree
892 {
893 tree init;
895 tree sorted_inits;
896 tree next_subobject;
901 /* Build up a list of initializations. The TREE_PURPOSE of entry
902 will be the subobject (a FIELD_DECL or BINFO) to initialize. The
903 TREE_VALUE will be the constructor arguments, or NULL if no
904 explicit initialization was provided. */
907 /* Process the virtual bases. */
912 /* Process the direct bases. */
918 /* Process the non-static data members. */
920 /* Reverse the entire list of initializations, so that they are in
921 the order that they will actually be performed. */
924 /* If the user presented the initializers in an order different from
925 that in which they will actually occur, we issue a warning. Keep
926 track of the next subobject which can be explicitly initialized
927 without issuing a warning. */
930 /* Go through the explicit initializers, filling in TREE_PURPOSE in
931 the SORTED_INITS. */
933 {
934 tree subobject;
935 tree subobject_init;
939 /* If the explicit initializers are in sorted order, then
940 SUBOBJECT will be NEXT_SUBOBJECT, or something following
941 it. */
943 subobject_init;
948 /* Issue a warning if the explicit initializer order does not
949 match that which will actually occur.
950 ??? Are all these on the correct lines? */
952 {
957 else
963 else
967 }
969 /* Look again, from the beginning of the list. */
971 {
975 }
977 /* It is invalid to initialize the same subobject more than
978 once. */
980 {
984 subobject);
985 else
988 subobject);
989 }
991 /* Record the initialization. */
994 }
996 /* [class.base.init]
998 If a ctor-initializer specifies more than one mem-initializer for
999 multiple members of the same union (including members of
1000 anonymous unions), the ctor-initializer is ill-formed.
1002 Here we also splice out uninitialized union members. */
1004 {
1008 {
1009 tree field;
1010 tree ctx;
1016 /* Skip base classes. */
1020 /* If this is an anonymous aggregate with no explicit initializer,
1021 splice it out. */
1025 /* See if this field is a member of a union, or a member of a
1026 structure contained in a union, etc. */
1029 /* If this field is not a member of a union, skip it. */
1034 /* If this union member has no explicit initializer and no NSDMI,
1035 splice it out. */
1038 else
1041 /* It's only an error if we have two initializers for the same
1042 union type. */
1044 {
1047 }
1049 /* See if LAST_FIELD and the field initialized by INIT are
1050 members of the same union (or the union itself). If so, there's
1051 a problem, unless they're actually members of the same structure
1052 which is itself a member of a union. For example, given:
1054 union { struct { int i; int j; }; };
1056 initializing both `i' and `j' makes sense. */
1057 ctx = common_enclosing_class
1063 {
1064 /* A mem-initializer hides an NSDMI. */
1069 else
1070 {
1073 ctx);
1075 }
1076 }
1080 next:
1083 splice:
1086 }
1087 }
1090 }
1092 /* Initialize all bases and members of CURRENT_CLASS_TYPE. MEM_INITS
1093 is a TREE_LIST giving the explicit mem-initializer-list for the
1094 constructor. The TREE_PURPOSE of each entry is a subobject (a
1095 FIELD_DECL or a BINFO) of the CURRENT_CLASS_TYPE. The TREE_VALUE
1096 is a TREE_LIST giving the arguments to the constructor or
1097 void_type_node for an empty list of arguments. */
1099 void
1101 {
1104 /* We will already have issued an error message about the fact that
1105 the type is incomplete. */
1112 {
1113 /* Delegating constructor. */
1117 }
1123 /* Sort the mem-initializers into the order in which the
1124 initializations should be performed. */
1129 /* Initialize base classes. */
1133 {
1137 /* We already have issued an error message. */
1142 {
1143 /* If these initializations are taking place in a copy constructor,
1144 the base class should probably be explicitly initialized if there
1145 is a user-defined constructor in the base class (other than the
1146 default constructor, which will be called anyway). */
1154 }
1156 /* Initialize the base. */
1158 {
1159 tree base_addr;
1165 tf_warning_or_error),
1166 arguments,
1167 flags,
1168 tf_warning_or_error);
1170 }
1172 /* C++14 DR1658 Means we do not have to construct vbases of
1173 abstract classes. */
1175 }
1178 /* Initialize the vptrs. */
1181 /* Initialize the data members. */
1183 {
1187 }
1188 }
1190 /* Returns the address of the vtable (i.e., the value that should be
1191 assigned to the vptr) for BINFO. */
1193 tree
1195 {
1197 tree vtbl;
1200 /* If this is a virtual primary base, then the vtable we want to store
1201 is that for the base this is being used as the primary base of. We
1202 can't simply skip the initialization, because we may be expanding the
1203 inits of a subobject constructor where the virtual base layout
1204 can be different. */
1208 /* Figure out what vtable BINFO's vtable is based on, and mark it as
1209 used. */
1213 /* Now compute the address to use when initializing the vptr. */
1219 }
1221 /* This code sets up the virtual function tables appropriate for
1222 the pointer DECL. It is a one-ply initialization.
1224 BINFO is the exact type that DECL is supposed to be. In
1225 multiple inheritance, this might mean "C's A" if C : A, B. */
1227 static void
1229 {
1231 tree vtt_index;
1233 /* Compute the initializer for vptr. */
1236 /* We may get this vptr from a VTT, if this is a subobject
1237 constructor or subobject destructor. */
1240 {
1241 tree vtbl2;
1242 tree vtt_parm;
1244 /* Compute the value to use, when there's a VTT. */
1250 /* The actual initializer is the VTT value only in the subobject
1251 constructor. In maybe_clone_body we'll substitute NULL for
1252 the vtt_parm in the case of the non-subobject constructor. */
1254 }
1256 /* Compute the location of the vtpr. */
1258 tf_warning_or_error),
1262 /* Assign the vtable to the vptr. */
1266 }
1268 /* If an exception is thrown in a constructor, those base classes already
1269 constructed must be destroyed. This function creates the cleanup
1270 for BINFO, which has just been constructed. If FLAG is non-NULL,
1271 it is a DECL which is nonzero when this base needs to be
1272 destroyed. */
1274 static void
1276 {
1277 tree expr;
1282 /* Call the destructor. */
1284 base_dtor_identifier,
1285 NULL,
1286 binfo,
1288 tf_warning_or_error);
1300 }
1302 /* Construct the virtual base-class VBASE passing the ARGUMENTS to its
1303 constructor. */
1305 static void
1307 {
1308 tree inner_if_stmt;
1309 tree exp;
1310 tree flag;
1312 /* If there are virtual base classes with destructors, we need to
1313 emit cleanups to destroy them if an exception is thrown during
1314 the construction process. These exception regions (i.e., the
1315 period during which the cleanups must occur) begin from the time
1316 the construction is complete to the end of the function. If we
1317 create a conditional block in which to initialize the
1318 base-classes, then the cleanup region for the virtual base begins
1319 inside a block, and ends outside of that block. This situation
1320 confuses the sjlj exception-handling code. Therefore, we do not
1321 create a single conditional block, but one for each
1322 initialization. (That way the cleanup regions always begin
1323 in the outer block.) We trust the back end to figure out
1324 that the FLAG will not change across initializations, and
1325 avoid doing multiple tests. */
1330 /* Compute the location of the virtual base. If we're
1331 constructing virtual bases, then we must be the most derived
1332 class. Therefore, we don't have to look up the virtual base;
1333 we already know where it is. */
1342 }
1344 /* Find the context in which this FIELD can be initialized. */
1346 static tree
1348 {
1351 /* Anonymous union members can be initialized in the first enclosing
1352 non-anonymous union context. */
1356 }
1358 /* Function to give error message if member initialization specification
1359 is erroneous. FIELD is the member we decided to initialize.
1360 TYPE is the type for which the initialization is being performed.
1361 FIELD must be a member of TYPE.
1363 MEMBER_NAME is the name of the member. */
1365 static int
1367 {
1371 {
1373 member_name);
1375 }
1377 {
1380 field);
1382 }
1384 {
1388 }
1390 {
1392 member_name);
1394 }
1397 }
1399 /* NAME is a FIELD_DECL, an IDENTIFIER_NODE which names a field, or it
1400 is a _TYPE node or TYPE_DECL which names a base for that type.
1401 Check the validity of NAME, and return either the base _TYPE, base
1402 binfo, or the FIELD_DECL of the member. If NAME is invalid, return
1403 NULL_TREE and issue a diagnostic.
1405 An old style unnamed direct single base construction is permitted,
1406 where NAME is NULL. */
1408 tree
1410 {
1411 tree basetype;
1412 tree field;
1418 {
1419 /* This is an obsolete unnamed base class initializer. The
1420 parser will already have warned about its use. */
1422 {
1425 current_class_type);
1428 basetype = BINFO_TYPE
1433 current_class_type);
1435 }
1436 }
1438 {
1441 }
1444 else
1448 {
1449 tree class_binfo;
1450 tree direct_binfo;
1451 tree virtual_binfo;
1462 /* Look for a direct base. */
1467 /* Look for a virtual base -- unless the direct base is itself
1468 virtual. */
1472 /* [class.base.init]
1474 If a mem-initializer-id is ambiguous because it designates
1475 both a direct non-virtual base class and an inherited virtual
1476 base class, the mem-initializer is ill-formed. */
1478 {
1480 basetype);
1482 }
1485 {
1489 else
1493 }
1496 }
1497 else
1498 {
1501 else
1506 }
1509 }
1511 /* This is like `expand_member_init', only it stores one aggregate
1512 value into another.
1514 INIT comes in two flavors: it is either a value which
1515 is to be stored in EXP, or it is a parameter list
1516 to go to a constructor, which will operate on EXP.
1517 If INIT is not a parameter list for a constructor, then set
1518 LOOKUP_ONLYCONVERTING.
1519 If FLAGS is LOOKUP_ONLYCONVERTING then it is the = init form of
1520 the initializer, if FLAGS is 0, then it is the (init) form.
1521 If `init' is a CONSTRUCTOR, then we emit a warning message,
1522 explaining that such initializations are invalid.
1524 If INIT resolves to a CALL_EXPR which happens to return
1525 something of the type we are looking for, then we know
1526 that we can safely use that call to perform the
1527 initialization.
1529 The virtual function table pointer cannot be set up here, because
1530 we do not really know its type.
1532 This never calls operator=().
1534 When initializing, nothing is CONST.
1536 A default copy constructor may have to be used to perform the
1537 initialization.
1539 A constructor or a conversion operator may have to be used to
1540 perform the initialization, but not both, as it would be ambiguous. */
1542 tree
1544 {
1545 tree stmt_expr;
1546 tree compound_stmt;
1567 {
1568 tree itype;
1570 /* An array may not be initialized use the parenthesized
1571 initialization form -- unless the initializer is "()". */
1573 {
1577 }
1578 /* Must arrange to initialize each element of EXP
1579 from elements of INIT. */
1589 complain);
1593 /* Restore the type of init unless it was used directly. */
1597 }
1601 /* Just know that we've seen something for this node. */
1615 }
1617 static void
1619 tsubst_flags_t complain)
1620 {
1622 tree ctor_name;
1624 /* It fails because there may not be a constructor which takes
1625 its own type as the first (or only parameter), but which does
1626 take other types via a conversion. So, if the thing initializing
1627 the expression is a unit element of type X, first try X(X&),
1628 followed by initialization by X. If neither of these work
1629 out, then look hard. */
1630 tree rval;
1633 /* If we have direct-initialization from an initializer list, pull
1634 it out of the TREE_LIST so the code below can see it. */
1637 {
1641 /* Only call reshape_init if it has not been called earlier
1642 by the callers. */
1645 }
1649 /* A brace-enclosed initializer for an aggregate. In C++0x this can
1650 happen for direct-initialization, too. */
1653 /* A CONSTRUCTOR of the target's type is a previously digested
1654 initializer, whether that happened just above or in
1655 cp_parser_late_parsing_nsdmi.
1657 A TARGET_EXPR with TARGET_EXPR_DIRECT_INIT_P or TARGET_EXPR_LIST_INIT_P
1658 set represents the whole initialization, so we shouldn't build up
1659 another ctor call. */
1666 {
1667 /* Early initialization via a TARGET_EXPR only works for
1668 complete objects. */
1675 }
1679 {
1680 /* Base subobjects should only get direct-initialization. */
1684 /* Do nothing. We hit this in two cases: Reference initialization,
1685 where we aren't initializing a real variable, so we don't want
1686 to run a new constructor; and catching an exception, where we
1687 have already built up the constructor call so we could wrap it
1689 else
1694 /* We need to protect the initialization of a catch parm with a
1695 call to terminate(), which shows up as a MUST_NOT_THROW_EXPR
1696 around the TARGET_EXPR for the copy constructor. See
1697 initialize_handler_parm. */
1698 {
1702 }
1703 else
1708 }
1713 {
1717 }
1718 else
1723 {
1724 /* Delegating constructor. */
1725 tree complete;
1726 tree base;
1729 /* Unshare the arguments for the second call. */
1732 {
1735 }
1738 complain);
1744 complain);
1747 }
1748 else
1749 {
1752 else
1755 complain);
1756 }
1762 {
1765 {
1769 }
1770 }
1772 /* FIXME put back convert_to_void? */
1775 }
1777 /* This function is responsible for initializing EXP with INIT
1778 (if any).
1780 BINFO is the binfo of the type for who we are performing the
1781 initialization. For example, if W is a virtual base class of A and B,
1782 and C : A, B.
1783 If we are initializing B, then W must contain B's W vtable, whereas
1784 were we initializing C, W must contain C's W vtable.
1786 TRUE_EXP is nonzero if it is the true expression being initialized.
1787 In this case, it may be EXP, or may just contain EXP. The reason we
1788 need this is because if EXP is a base element of TRUE_EXP, we
1789 don't necessarily know by looking at EXP where its virtual
1790 baseclass fields should really be pointing. But we do know
1791 from TRUE_EXP. In constructors, we don't know anything about
1792 the value being initialized.
1794 FLAGS is just passed to `build_new_method_call'. See that function
1795 for its description. */
1797 static void
1799 tsubst_flags_t complain)
1800 {
1806 /* Use a function returning the desired type to initialize EXP for us.
1807 If the function is a constructor, and its first argument is
1808 NULL_TREE, know that it was meant for us--just slide exp on
1809 in and expand the constructor. Constructors now come
1810 as TARGET_EXPRs. */
1814 {
1816 /* If store_init_value returns NULL_TREE, the INIT has been
1817 recorded as the DECL_INITIAL for EXP. That means there's
1818 nothing more we have to do. */
1824 }
1826 /* List-initialization from {} becomes value-initialization for non-aggregate
1827 classes with default constructors. Handle this here when we're
1828 initializing a base, so protected access works. */
1830 {
1837 }
1839 /* If an explicit -- but empty -- initializer list was present,
1840 that's value-initialization. */
1842 {
1843 /* If the type has data but no user-provided ctor, we need to zero
1844 out the object. */
1847 {
1850 /* Don't clobber already initialized virtual bases. */
1853 field_size);
1856 }
1858 /* If we don't need to mess with the constructor at all,
1859 then we're done. */
1863 /* Otherwise fall through and call the constructor. */
1865 }
1867 /* We know that expand_default_init can handle everything we want
1868 at this point. */
1870 }
1872 /* Report an error if TYPE is not a user-defined, class type. If
1873 OR_ELSE is nonzero, give an error message. */
1875 int
1877 {
1882 {
1886 }
1888 }
1890 tree
1892 {
1898 else
1900 }
1902 /* Build a reference to a member of an aggregate. This is not a C++
1903 `&', but really something which can have its address taken, and
1904 then act as a pointer to member, for example TYPE :: FIELD can have
1905 its address taken by saying & TYPE :: FIELD. ADDRESS_P is true if
1906 this expression is the operand of "&".
1908 @@ Prints out lousy diagnostics for operator <typename>
1909 @@ fields.
1911 @@ This function should be rewritten and placed in search.c. */
1913 tree
1915 tsubst_flags_t complain)
1916 {
1917 tree decl;
1920 /* class templates can come in as TEMPLATE_DECLs here. */
1933 /* Callers should call mark_used before this point. */
1938 {
1942 }
1944 /* Entities other than non-static members need no further
1945 processing. */
1952 {
1956 }
1958 /* Set up BASEBINFO for member lookup. */
1961 /* A lot of this logic is now handled in lookup_member. */
1963 {
1964 /* Go from the TREE_BASELINK to the member function info. */
1968 {
1969 /* Get rid of a potential OVERLOAD around it. */
1972 /* Unique functions are handled easily. */
1974 /* For non-static member of base class, we need a special rule
1975 for access checking [class.protected]:
1977 If the access is to form a pointer to member, the
1978 nested-name-specifier shall name the derived class
1979 (or any class derived from that class). */
1983 complain);
1984 else
1986 complain);
1991 }
1992 else
1994 }
1996 /* We need additional test besides the one in
1997 check_accessibility_of_qualified_id in case it is
1998 a pointer to non-static member. */
2000 complain);
2003 {
2004 /* If MEMBER is non-static, then the program has fallen afoul of
2005 [expr.prim]:
2007 An id-expression that denotes a nonstatic data member or
2008 nonstatic member function of a class can only be used:
2010 -- as part of a class member access (_expr.ref_) in which the
2011 object-expression refers to the member's class or a class
2012 derived from that class, or
2014 -- to form a pointer to member (_expr.unary.op_), or
2016 -- in the body of a nonstatic member function of that class or
2017 of a class derived from that class (_class.mfct.nonstatic_), or
2019 -- in a mem-initializer for a constructor for that class or for
2020 a class derived from that class (_class.base.init_). */
2022 {
2023 /* Build a representation of the qualified name suitable
2024 for use as the operand to "&" -- even though the "&" is
2025 not actually present. */
2027 /* In Microsoft mode, treat a non-static member function as if
2028 it were a pointer-to-member. */
2030 {
2033 }
2038 }
2040 {
2044 }
2046 }
2051 }
2053 /* If DECL is a scalar enumeration constant or variable with a
2054 constant initializer, return the initializer (or, its initializers,
2055 recursively); otherwise, return DECL. If STRICT_P, the
2056 initializer is only returned if DECL is a
2057 constant-expression. If RETURN_AGGREGATE_CST_OK_P, it is ok to
2058 return an aggregate constant. */
2060 static tree
2062 {
2064 || (strict_p
2068 {
2069 tree init;
2070 /* If DECL is a static data member in a template
2071 specialization, we must instantiate it here. The
2072 initializer for the static data member is not processed
2073 until needed; we need it now. */
2078 {
2080 /* Treat the error as a constant to avoid cascading errors on
2081 excessively recursive template instantiation (c++/9335). */
2083 else
2085 }
2086 /* Initializers in templates are generally expanded during
2087 instantiation, so before that for const int i(2)
2088 INIT is a TREE_LIST with the actual initializer as
2089 TREE_VALUE. */
2091 && init
2095 /* Instantiate a non-dependent initializer for user variables. We
2096 mustn't do this for the temporary for an array compound literal;
2097 trying to instatiate the initializer will keep creating new
2098 temporaries until we crash. Probably it's not useful to do it for
2099 other artificial variables, either. */
2105 || (!return_aggregate_cst_ok_p
2106 /* Unless RETURN_AGGREGATE_CST_OK_P is true, do not
2107 return an aggregate constant (of which string
2108 literals are a special case), as we do not want
2109 to make inadvertent copies of such entities, and
2110 we must be sure that their addresses are the
2111 same everywhere. */
2115 /* Don't return a CONSTRUCTOR for a variable with partial run-time
2116 initialization, since it doesn't represent the entire value. */
2121 }
2123 }
2125 /* If DECL is a CONST_DECL, or a constant VAR_DECL initialized by constant
2126 of integral or enumeration type, or a constexpr variable of scalar type,
2127 then return that value. These are those variables permitted in constant
2128 expressions by [5.19/1]. */
2130 tree
2132 {
2135 }
2137 /* Like scalar_constant_value, but can also return aggregate initializers. */
2139 tree
2141 {
2144 }
2146 /* A more relaxed version of scalar_constant_value, used by the
2147 common C/C++ code. */
2149 tree
2151 {
2154 }
2155 \f
2156 /* Common subroutines of build_new and build_vec_delete. */
2157 \f
2158 /* Build and return a NEW_EXPR. If NELTS is non-NULL, TYPE[NELTS] is
2159 the type of the object being allocated; otherwise, it's just TYPE.
2160 INIT is the initializer, if any. USE_GLOBAL_NEW is true if the
2161 user explicitly wrote "::operator new". PLACEMENT, if non-NULL, is
2162 a vector of arguments to be provided as arguments to a placement
2163 new operator. This routine performs no semantic checks; it just
2164 creates and returns a NEW_EXPR. */
2166 static tree
2169 {
2170 tree init_list;
2171 tree new_expr;
2173 /* If INIT is NULL, the we want to store NULL_TREE in the NEW_EXPR.
2174 If INIT is not NULL, then we want to store VOID_ZERO_NODE. This
2175 permits us to distinguish the case of a missing initializer "new
2176 int" from an empty initializer "new int()". */
2181 else
2186 init_list);
2191 }
2193 /* Diagnose uninitialized const members or reference members of type
2194 TYPE. USING_NEW is used to disambiguate the diagnostic between a
2195 new expression without a new-initializer and a declaration. Returns
2196 the error count. */
2198 static int
2201 {
2202 tree field;
2209 {
2210 tree field_type;
2221 {
2224 {
2226 {
2230 else
2232 }
2233 else
2234 {
2239 else
2242 }
2245 }
2246 }
2249 {
2252 {
2254 {
2258 else
2260 }
2261 else
2262 {
2267 else
2270 }
2273 }
2274 }
2277 error_count
2280 }
2282 }
2284 int
2286 {
2288 }
2290 /* Call __cxa_bad_array_new_length to indicate that the size calculation
2291 overflowed. Pretend it returns sizetype so that it plays nicely in the
2292 COND_EXPR. */
2294 tree
2296 {
2300 NULL_TREE));
2303 }
2305 /* Attempt to find the initializer for field T in the initializer INIT,
2306 when non-null. Returns the initializer when successful and NULL
2307 otherwise. */
2308 static tree
2310 {
2317 /* Iterate over all top-level initializer elements. */
2319 {
2320 /* If the member T is found, return it. */
2324 /* Otherwise continue and/or recurse into nested initializers. */
2328 }
2330 }
2332 /* Attempt to verify that the argument, OPER, of a placement new expression
2333 refers to an object sufficiently large for an object of TYPE or an array
2334 of NELTS of such objects when NELTS is non-null, and issue a warning when
2335 it does not. SIZE specifies the size needed to construct the object or
2336 array and captures the result of NELTS * sizeof (TYPE). (SIZE could be
2337 greater when the array under construction requires a cookie to store
2338 NELTS. GCC's placement new expression stores the cookie when invoking
2339 a user-defined placement new operator function but not the default one.
2340 Placement new expressions with user-defined placement new operator are
2341 not diagnosed since we don't know how they use the buffer (this could
2342 be a future extension). */
2343 static void
2345 {
2348 /* The number of bytes to add to or subtract from the size of the provided
2349 buffer based on an offset into an array or an array element reference.
2350 Although intermediate results may be negative (as in a[3] - 2) the final
2351 result cannot be. */
2353 /* True when the size of the entire destination object should be used
2354 to compute the possibly optimistic estimate of the available space. */
2356 /* True when the reference to the destination buffer is an ADDR_EXPR. */
2361 /* Using a function argument or a (non-array) variable as an argument
2362 to placement new is not checked since it's unknown what it might
2363 point to. */
2369 /* Evaluate any constant expressions. */
2372 /* Handle the common case of array + offset expression when the offset
2373 is a constant. */
2375 {
2376 /* If the offset is comple-time constant, use it to compute a more
2377 accurate estimate of the size of the buffer. Since the operand
2378 of POINTER_PLUS_EXPR is represented as an unsigned type, convert
2379 it to signed first.
2380 Otherwise, use the size of the entire array as an optimistic
2381 estimate (this may lead to false negatives). */
2385 else
2391 }
2396 {
2399 }
2405 {
2406 /* Similar to the offset computed above, see if the array index
2407 is a compile-time constant. If so, and unless the offset was
2408 not a compile-time constant, use the index to determine the
2409 size of the buffer. Otherwise, use the entire array as
2410 an optimistic estimate of the size. */
2414 else
2415 {
2418 }
2421 }
2423 /* Refers to the declared object that constains the subobject referenced
2424 by OPER. When the object is initialized, makes it possible to determine
2425 the actual size of a flexible array member used as the buffer passed
2426 as OPER to placement new. */
2428 /* True when operand is a COMPONENT_REF, to distinguish flexible array
2429 members from arrays of unspecified size. */
2432 /* Descend into a struct or union to find the member whose address
2433 is being used as the argument. */
2435 {
2441 }
2447 {
2448 /* A possibly optimistic estimate of the number of bytes available
2449 in the destination buffer. */
2451 /* True when the estimate above is in fact the exact size
2452 of the destination buffer rather than an estimate. */
2455 /* Treat members of unions and members of structs uniformly, even
2456 though the size of a member of a union may be viewed as extending
2457 to the end of the union itself (it is by __builtin_object_size). */
2461 {
2462 /* Use the size of the entire array object when the expression
2463 refers to a variable or its size depends on an expression
2464 that's not a compile-time constant. */
2467 }
2470 {
2471 /* Use the size of the type of the destination buffer object
2472 as the optimistic estimate of the available space in it. */
2474 }
2476 {
2477 /* Constructing into a buffer provided by the flexible array
2478 member of a declared object (which is permitted as a G++
2479 extension). If the array member has been initialized,
2480 determine its size from the initializer. Otherwise,
2481 the array size is zero. */
2486 }
2487 else
2488 {
2489 /* Bail if neither the size of the object nor its type is known. */
2491 }
2496 {
2497 /* Avoid diagnosing flexible array members (which are accepted
2498 as an extension and diagnosed with -Wpedantic) and zero-length
2499 arrays (also an extension).
2500 Overflowing construction in one-element arrays is diagnosed
2501 only at level 2. */
2509 && !var_decl
2512 }
2514 /* The size of the buffer can only be adjusted down but not up. */
2517 /* Reduce the size of the buffer by the adjustment computed above
2518 from the offset and/or the index into the array. */
2521 else
2524 /* The minimum amount of space needed for the allocation. This
2525 is an optimistic estimate that makes it possible to detect
2526 placement new invocation for some undersize buffers but not
2527 others. */
2537 else
2538 {
2539 /* The type is a VLA. */
2541 }
2544 {
2548 exact_size ?
2549 "placement new constructing an object of type "
2550 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2551 "and size %qwi"
2553 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2557 bytes_avail);
2558 else
2560 exact_size ?
2561 "placement new constructing an array of objects "
2562 "of type %qT and size %qwu in a region of type %qT "
2563 "and size %qwi"
2565 "of type %qT and size %qwu in a region of type %qT "
2568 bytes_avail);
2569 else
2571 exact_size ?
2572 "placement new constructing an object of type %qT "
2573 "and size %qwu in a region of type %qT and size %qwi"
2575 "and size %qwu in a region of type %qT and size "
2578 bytes_avail);
2579 }
2580 }
2581 }
2583 /* True if alignof(T) > __STDCPP_DEFAULT_NEW_ALIGNMENT__. */
2585 bool
2587 {
2590 }
2592 /* Generate code for a new-expression, including calling the "operator
2593 new" function, initializing the object, and, if an exception occurs
2594 during construction, cleaning up. The arguments are as for
2595 build_raw_new_expr. This may change PLACEMENT and INIT.
2596 TYPE is the type of the object being constructed, possibly an array
2597 of NELTS elements when NELTS is non-null (in "new T[NELTS]", T may
2598 be an array of the form U[inner], with the whole expression being
2599 "new U[NELTS][inner]"). */
2601 static tree
2604 tsubst_flags_t complain)
2605 {
2607 /* True iff this is a call to "operator new[]" instead of just
2608 "operator new". */
2610 /* If ARRAY_P is true, the element type of the array. This is never
2611 an ARRAY_TYPE; for something like "new int[3][4]", the
2612 ELT_TYPE is "int". If ARRAY_P is false, this is the same type as
2613 TYPE. */
2614 tree elt_type;
2615 /* The type of the new-expression. (This type is always a pointer
2616 type.) */
2617 tree pointer_type;
2618 tree non_const_pointer_type;
2619 /* The most significant array bound in int[OUTER_NELTS][inner]. */
2621 /* For arrays with a non-constant number of elements, a bounds checks
2622 on the NELTS parameter to avoid integer overflow at runtime. */
2625 /* Number of the "inner" elements in "new T[OUTER_NELTS][inner]". */
2628 /* Size of the inner array elements (those with constant dimensions). */
2629 offset_int inner_size;
2630 /* The address returned by the call to "operator new". This node is
2631 a VAR_DECL and is therefore reusable. */
2632 tree alloc_node;
2633 tree alloc_fn;
2636 /* If non-NULL, the number of extra bytes to allocate at the
2637 beginning of the storage allocated for an array-new expression in
2638 order to store the number of elements. */
2640 tree placement_first;
2642 /* True if the function we are calling is a placement allocation
2643 function. */
2645 /* True if the storage must be initialized, either by a constructor
2646 or due to an explicit new-initializer. */
2648 /* The address of the thing allocated, not including any cookie. In
2649 particular, if an array cookie is in use, DATA_ADDR is the
2650 address of the first array element. This node is a VAR_DECL, and
2651 is therefore reusable. */
2652 tree data_addr;
2657 {
2660 }
2662 {
2663 /* Transforms new (T[N]) to new T[N]. The former is a GNU
2664 extension for variable N. (This also covers new T where T is
2665 a VLA typedef.) */
2671 }
2673 /* Lots of logic below. depends on whether we have a constant number of
2674 elements, so go ahead and fold it now. */
2678 /* If our base type is an array, then make sure we know how many elements
2679 it has. */
2683 {
2687 {
2692 {
2696 }
2698 }
2699 else
2700 {
2702 {
2706 }
2708 }
2712 inner_nelts_cst,
2713 complain);
2714 }
2717 {
2720 }
2725 /* Warn if we performed the (T[N]) to T[N] transformation and N is
2726 variable. */
2729 {
2731 {
2736 else
2741 }
2742 else
2744 }
2747 {
2751 }
2759 {
2761 /* A program that calls for default-initialization [...] of an
2762 entity of reference type is ill-formed. */
2766 /* A new-expression that creates an object of type T initializes
2767 that object as follows:
2768 - If the new-initializer is omitted:
2769 -- If T is a (possibly cv-qualified) non-POD class type
2770 (or array thereof), the object is default-initialized (8.5).
2771 [...]
2772 -- Otherwise, the object created has indeterminate
2773 value. If T is a const-qualified type, or a (possibly
2774 cv-qualified) POD class type (or array thereof)
2775 containing (directly or indirectly) a member of
2776 const-qualified type, the program is ill-formed; */
2786 }
2790 {
2794 }
2798 {
2799 /* Maximum available size in bytes. Half of the address space
2800 minus the cookie size. */
2801 offset_int max_size
2803 /* Maximum number of outer elements which can be allocated. */
2804 offset_int max_outer_nelts;
2805 tree max_outer_nelts_tree;
2811 /* Unconditionally subtract the cookie size. This decreases the
2812 maximum object size and is safe even if we choose not to use
2813 a cookie after all. */
2819 {
2823 }
2831 {
2833 {
2834 /* When the array size is constant, check it at compile time
2835 to make sure it doesn't exceed the implementation-defined
2836 maximum, as required by C++ 14 (in C++ 11 this requirement
2837 isn't explicitly stated but it's enforced anyway -- see
2838 grokdeclarator in cp/decl.c). */
2842 }
2843 }
2844 else
2845 {
2846 /* When a runtime check is necessary because the array size
2847 isn't constant, keep only the top-most seven bits (starting
2848 with the most significant non-zero bit) of the maximum size
2849 to compare the array size against, to simplify encoding the
2850 constant maximum size in the instruction stream. */
2857 outer_nelts,
2858 max_outer_nelts_tree);
2859 }
2860 }
2868 /* If PLACEMENT is a single simple pointer type not passed by
2869 reference, prepare to capture it in a temporary variable. Do
2870 this now, since PLACEMENT will change in the calls below. */
2878 /* Allocate the object. */
2879 tree fnname;
2880 tree fns;
2884 member_new_p = !globally_qualified_p
2886 && (array_p
2891 {
2892 /* Use a class-specific operator new. */
2893 /* If a cookie is required, add some extra space. */
2896 else
2897 {
2899 /* No size arithmetic necessary, so the size check is
2900 not needed. */
2903 }
2904 /* Perform the overflow check. */
2911 /* Create the argument list. */
2913 /* Do name-lookup to find the appropriate operator. */
2916 {
2920 }
2922 {
2924 {
2927 }
2929 }
2933 {
2936 alloc_call
2940 /* If no matching function is found and the allocated object type
2941 has new-extended alignment, the alignment argument is removed
2942 from the argument list, and overload resolution is performed
2943 again. */
2946 }
2950 LOOKUP_NORMAL,
2952 }
2953 else
2954 {
2955 /* Use a global operator new. */
2956 /* See if a cookie might be required. */
2958 {
2960 /* No size arithmetic necessary, so the size check is
2961 not needed. */
2964 }
2970 }
2982 {
2990 }
2992 /* If we found a simple case of PLACEMENT_EXPR above, then copy it
2993 into a temporary variable. */
2999 {
3005 {
3009 }
3013 {
3014 /* Attempt to make the warning point at the operator new argument. */
3019 }
3020 }
3022 /* In the simple case, we can stop now. */
3027 /* Store the result of the allocation call in a variable so that we can
3028 use it more than once. */
3032 /* Strip any COMPOUND_EXPRs from ALLOC_CALL. */
3036 /* Now, check to see if this function is actually a placement
3037 allocation function. This can happen even when PLACEMENT is NULL
3038 because we might have something like:
3040 struct S { void* operator new (size_t, int i = 0); };
3042 A call to `new S' will get this allocation function, even though
3043 there is no explicit placement argument. If there is more than
3044 one argument, or there are variable arguments, then this is a
3045 placement allocation function. */
3046 placement_allocation_fn_p
3050 /* Preevaluate the placement args so that we don't reevaluate them for a
3051 placement delete. */
3053 {
3054 tree inits;
3058 alloc_expr);
3059 }
3061 /* unless an allocation function is declared with an empty excep-
3062 tion-specification (_except.spec_), throw(), it indicates failure to
3063 allocate storage by throwing a bad_alloc exception (clause _except_,
3064 _lib.bad.alloc_); it returns a non-null pointer otherwise If the allo-
3065 cation function is declared with an empty exception-specification,
3066 throw(), it returns null to indicate failure to allocate storage and a
3067 non-null pointer otherwise.
3069 So check for a null exception spec on the op new we just called. */
3075 {
3076 tree cookie;
3077 tree cookie_ptr;
3078 tree size_ptr_type;
3080 /* Adjust so we're pointing to the start of the object. */
3083 /* Store the number of bytes allocated so that we can know how
3084 many elements to destroy later. We use the last sizeof
3085 (size_t) bytes to store the number of elements. */
3096 {
3097 /* Also store the element size. */
3108 }
3109 }
3110 else
3111 {
3114 }
3116 /* Now use a pointer to the type we've actually allocated. */
3118 /* But we want to operate on a non-const version to start with,
3119 since we'll be modifying the elements. */
3120 non_const_pointer_type = build_pointer_type
3124 /* Any further uses of alloc_node will want this type, too. */
3127 /* Now initialize the allocated object. Note that we preevaluate the
3128 initialization expression, apart from the actual constructor call or
3129 assignment--we do this because we want to delay the allocation as long
3130 as possible in order to minimize the size of the exception region for
3131 placement delete. */
3133 {
3138 {
3141 }
3144 {
3145 /* build_value_init doesn't work in templates, and we don't need
3146 the initializer anyway since we're going to throw it away and
3147 rebuild it at instantiation time, so just build up a single
3148 constructor call to get any appropriate diagnostics. */
3152 complete_ctor_identifier,
3154 LOOKUP_NORMAL,
3155 complain);
3157 }
3159 {
3163 {
3167 else
3168 {
3172 complain);
3173 else
3174 /* We'll check the length at runtime. */
3178 }
3179 }
3181 {
3185 else
3188 }
3189 init_expr
3193 integer_one_node,
3194 complain),
3195 vecinit,
3196 explicit_value_init_p,
3198 complain);
3200 /* An array initialization is stable because the initialization
3201 of each element is a full-expression, so the temporaries don't
3202 leak out. */
3204 }
3205 else
3206 {
3210 {
3212 complete_ctor_identifier,
3214 LOOKUP_NORMAL,
3215 complain);
3216 }
3218 {
3219 /* Something like `new int()'. */
3224 }
3225 else
3226 {
3227 tree ie;
3229 /* We are processing something like `new int (10)', which
3230 means allocate an int, and initialize it with 10. */
3233 complain);
3236 }
3238 }
3243 /* If any part of the object initialization terminates by throwing an
3244 exception and a suitable deallocation function can be found, the
3245 deallocation function is called to free the memory in which the
3246 object was being constructed, after which the exception continues
3247 to propagate in the context of the new-expression. If no
3248 unambiguous matching deallocation function can be found,
3249 propagating the exception does not cause the object's memory to be
3250 freed. */
3252 {
3254 tree cleanup;
3256 /* The Standard is unclear here, but the right thing to do
3257 is to use the same method for finding deallocation
3258 functions that we use for finding allocation functions. */
3259 cleanup = (build_op_delete_call
3261 alloc_node,
3262 size,
3263 globally_qualified_p,
3265 alloc_fn,
3266 complain));
3271 /* This is much simpler if we were able to preevaluate all of
3272 the arguments to the constructor call. */
3273 {
3274 /* CLEANUP is compiler-generated, so no diagnostics. */
3278 /* Likewise, this try-catch is compiler-generated. */
3280 }
3281 else
3282 /* Ack! First we allocate the memory. Then we set our sentry
3283 variable to true, and expand a cleanup that deletes the
3284 memory if sentry is true. Then we run the constructor, and
3285 finally clear the sentry.
3287 We need to do this because we allocate the space first, so
3288 if there are any temporaries with cleanups in the
3289 constructor args and we weren't able to preevaluate them, we
3290 need this EH region to extend until end of full-expression
3291 to preserve nesting. */
3292 {
3300 /* CLEANUP is compiler-generated, so no diagnostics. */
3310 init_expr
3313 end));
3314 /* Likewise, this is compiler-generated. */
3316 }
3317 }
3318 }
3319 else
3322 /* Now build up the return value in reverse order. */
3332 /* If we don't have an initializer or a cookie, strip the TARGET_EXPR
3333 and return the call (which doesn't need to be adjusted). */
3335 else
3336 {
3338 {
3341 nullptr_node,
3342 complain);
3345 }
3347 /* Perform the allocation before anything else, so that ALLOC_NODE
3348 has been initialized before we start using it. */
3350 }
3355 /* A new-expression is never an lvalue. */
3359 }
3361 /* Generate a representation for a C++ "new" expression. *PLACEMENT
3362 is a vector of placement-new arguments (or NULL if none). If NELTS
3363 is NULL, TYPE is the type of the storage to be allocated. If NELTS
3364 is not NULL, then this is an array-new allocation; TYPE is the type
3365 of the elements in the array and NELTS is the number of elements in
3366 the array. *INIT, if non-NULL, is the initializer for the new
3367 object, or an empty vector to indicate an initializer of "()". If
3368 USE_GLOBAL_NEW is true, then the user explicitly wrote "::new"
3369 rather than just "new". This may change PLACEMENT and INIT. */
3371 tree
3374 {
3375 tree rval;
3384 /* Don't do auto deduction where it might affect mangling. */
3386 {
3389 {
3393 }
3394 }
3397 {
3404 use_global_new);
3415 }
3418 {
3420 {
3423 else
3425 }
3427 /* Try to determine the constant value only for the purposes
3428 of the diagnostic below but continue to use the original
3429 value and handle const folding later. */
3432 /* The expression in a noptr-new-declarator is erroneous if it's of
3433 non-class type and its value before converting to std::size_t is
3434 less than zero. ... If the expression is a constant expression,
3435 the program is ill-fomed. */
3438 {
3442 }
3446 }
3448 /* ``A reference cannot be created by the new operator. A reference
3449 is not an object (8.2.2, 8.4.3), so a pointer to it could not be
3450 returned by new.'' ARM 5.3.3 */
3452 {
3455 else
3458 }
3461 {
3465 }
3467 /* The type allocated must be complete. If the new-type-id was
3468 "T[N]" then we are just checking that "T" is complete here, but
3469 that is equivalent, since the value of "N" doesn't matter. */
3478 {
3484 }
3486 /* Wrap it in a NOP_EXPR so warn_if_unused_value doesn't complain. */
3491 }
3492 \f
3493 static tree
3495 special_function_kind auto_delete_vec,
3497 {
3498 tree virtual_size;
3500 tree size_exp;
3502 /* Temporary variables used by the loop. */
3505 /* This is the body of the loop that implements the deletion of a
3506 single element, and moves temp variables to next elements. */
3507 tree body;
3509 /* This is the LOOP_EXPR that governs the deletion of the elements. */
3512 /* This is the thing that governs what to do after the loop has run. */
3515 /* This is the BIND_EXPR which holds the outermost iterator of the
3516 loop. It is convenient to set this variable up and test it before
3517 executing any other code in the loop.
3518 This is also the containing expression returned by this function. */
3520 tree tmp;
3522 /* We should only have 1-D arrays here. */
3529 {
3532 "possible problem detected in invocation of "
3534 {
3537 "class-specific operator delete [] will be called, "
3539 }
3540 /* This size won't actually be used. */
3543 }
3550 {
3551 /* Make sure the destructor is callable. */
3553 {
3556 complain);
3559 }
3561 }
3563 /* The below is short by the cookie size. */
3568 tbase_init
3572 base),
3573 virtual_size),
3574 complain);
3592 complain);
3600 no_destructor:
3601 /* Delete the storage if appropriate. */
3603 {
3604 tree base_tbd;
3606 /* The below is short by the cookie size. */
3611 /* no header */
3613 else
3614 {
3615 tree cookie_size;
3619 MINUS_EXPR,
3622 cookie_size,
3623 complain);
3627 /* True size with header. */
3629 }
3636 complain);
3637 }
3641 ;
3644 else
3645 /* The delete operator mist be called, even if a destructor
3646 throws. */
3652 /* Outermost wrapper: If pointer is null, punt. */
3655 /* This is a compiler generated comparison, don't emit
3656 e.g. -Wnonnull-compare warning for it. */
3664 {
3667 }
3670 /* Pre-evaluate the SAVE_EXPR outside of the BIND_EXPR. */
3674 }
3676 /* Create an unnamed variable of the indicated TYPE. */
3678 tree
3680 {
3681 tree decl;
3691 }
3693 /* Create a new temporary variable of the indicated TYPE, initialized
3694 to INIT.
3696 It is not entered into current_binding_level, because that breaks
3697 things when it comes time to do final cleanups (which take place
3698 "outside" the binding contour of the function). */
3700 tree
3702 {
3703 tree decl;
3712 }
3714 /* Subroutine of build_vec_init. Returns true if assigning to an array of
3715 INNER_ELT_TYPE from INIT is trivial. */
3717 static bool
3719 {
3724 }
3726 /* `build_vec_init' returns tree structure that performs
3727 initialization of a vector of aggregate types.
3729 BASE is a reference to the vector, of ARRAY_TYPE, or a pointer
3730 to the first element, of POINTER_TYPE.
3731 MAXINDEX is the maximum index of the array (one less than the
3732 number of elements). It is only used if BASE is a pointer or
3733 TYPE_DOMAIN (TREE_TYPE (BASE)) == NULL_TREE.
3735 INIT is the (possibly NULL) initializer.
3737 If EXPLICIT_VALUE_INIT_P is true, then INIT must be NULL. All
3738 elements in the array are value-initialized.
3740 FROM_ARRAY is 0 if we should init everything with INIT
3741 (i.e., every element initialized from INIT).
3742 FROM_ARRAY is 1 if we should index into INIT in parallel
3743 with initialization of DECL.
3744 FROM_ARRAY is 2 if we should index into INIT in parallel,
3745 but use assignment instead of initialization. */
3747 tree
3751 {
3752 tree rval;
3755 tree iterator;
3756 /* The type of BASE. */
3758 /* The type of an element in the array. */
3760 /* The element type reached after removing all outer array
3761 types. */
3762 tree inner_elt_type;
3763 /* The type of a pointer to an element in the array. */
3764 tree ptype;
3765 tree stmt_expr;
3766 tree compound_stmt;
3787 /* Look through the TARGET_EXPR around a compound literal. */
3793 /* If we have a braced-init-list, make sure that the array
3794 is big enough for all the initializers. */
3806 /* Don't do this if the CONSTRUCTOR might contain something
3807 that might throw and require us to clean up. */
3811 {
3812 /* Do non-default initialization of trivial arrays resulting from
3813 brace-enclosed initializers. In this case, digest_init and
3814 store_constructor will handle the semantics for us. */
3820 }
3826 {
3832 }
3833 else
3836 /* The code we are generating looks like:
3837 ({
3838 T* t1 = (T*) base;
3839 T* rval = t1;
3840 ptrdiff_t iterator = maxindex;
3841 try {
3842 for (; iterator != -1; --iterator) {
3843 ... initialize *t1 ...
3844 ++t1;
3845 }
3846 } catch (...) {
3847 ... destroy elements that were constructed ...
3848 }
3849 rval;
3850 })
3852 We can omit the try and catch blocks if we know that the
3853 initialization will never throw an exception, or if the array
3854 elements do not have destructors. We can omit the loop completely if
3855 the elements of the array do not have constructors.
3857 We actually wrap the entire body of the above in a STMT_EXPR, for
3858 tidiness.
3860 When copying from array to another, when the array elements have
3861 only trivial copy constructors, we should use __builtin_memcpy
3862 rather than generating a loop. That way, we could take advantage
3863 of whatever cleverness the back end has for dealing with copies
3864 of blocks of memory. */
3873 /* If initializing one array from another, initialize element by
3874 element. We rely upon the below calls to do the argument
3875 checking. Evaluate the initializer before entering the try block. */
3877 {
3886 }
3888 /* Protect the entire array initialization so that we can destroy
3889 the partially constructed array if an exception is thrown.
3890 But don't do this if we're assigning. */
3893 {
3895 }
3897 /* Should we try to create a constant initializer? */
3901 : (type_has_constexpr_default_constructor
3907 /* If we're initializing a static array, we want to do static
3908 initialization of any elements with constant initializers even if
3909 some are non-constant. */
3915 /* Skip over the handling of non-empty init lists. */
3918 /* Maybe pull out constant value when from_array? */
3921 {
3922 /* Do non-default initialization of non-trivial arrays resulting from
3923 brace-enclosed initializers. */
3926 /* If the constructor already has the array type, it's been through
3927 digest_init, so we shouldn't try to do anything more. */
3932 {
3936 {
3938 {
3940 nelts);
3944 }
3945 /* Don't check an array new when -fno-exceptions. */
3946 }
3949 {
3950 /* Make sure the last element of the initializer is in bounds. */
3951 finish_expr_stmt
3952 (ubsan_instrument_bounds
3954 }
3955 }
3961 {
3963 tree one_init;
3965 num_initialized_elts++;
3972 else
3978 {
3981 {
3985 else
3987 }
3988 else
3989 {
3991 {
3996 }
3998 }
3999 }
4006 complain);
4009 else
4013 complain);
4016 else
4018 }
4020 /* Any elements without explicit initializers get T{}. */
4022 }
4024 {
4029 {
4033 }
4034 }
4036 /* Now, default-initialize any remaining elements. We don't need to
4037 do that if a) the type does not need constructing, or b) we've
4038 already initialized all the elements.
4040 We do need to keep going if we're copying an array. */
4043 /* With a constexpr default constructor, which we checked for when
4044 setting try_const above, default-initialization is equivalent to
4045 value-initialization, and build_value_init gives us something more
4046 friendly to maybe_constant_init. */
4051 && (num_initialized_elts
4053 {
4054 /* If the ITERATOR is lesser or equal to -1, then we don't have to loop;
4055 we've already initialized all the elements. */
4056 tree for_stmt;
4057 tree elt_init;
4058 tree to;
4066 complain);
4073 /* If the initializer is {}, then all elements are initialized from T{}.
4074 But for non-classes, that's the same as value-initialization. */
4076 {
4078 {
4080 }
4081 else
4082 {
4085 }
4086 }
4089 {
4090 tree from;
4093 {
4097 }
4098 else
4108 complain);
4109 else
4111 }
4113 {
4115 sorry
4119 explicit_value_init_p,
4121 }
4123 {
4127 }
4128 else
4129 {
4133 else
4134 {
4137 complain);
4139 }
4140 }
4146 {
4147 /* FIXME refs to earlier elts */
4150 {
4152 /* Don't fill the CONSTRUCTOR with zeros. */
4156 }
4157 else
4158 {
4162 else
4164 }
4167 {
4170 {
4173 }
4174 }
4175 }
4183 complain));
4186 complain));
4189 }
4191 /* Make sure to cleanup any partially constructed elements. */
4194 {
4195 tree e;
4198 complain);
4200 /* Flatten multi-dimensional array since build_vec_delete only
4201 expects one-dimensional array. */
4205 /* Avoid mixing signed and unsigned. */
4208 complain);
4217 }
4219 /* The value of the array initialization is the array itself, RVAL
4220 is a pointer to the first element. */
4231 {
4233 {
4236 }
4239 else
4241 }
4243 /* Now make the result have the correct type. */
4245 {
4250 }
4253 }
4255 /* Call the DTOR_KIND destructor for EXP. FLAGS are as for
4256 build_delete. */
4258 static tree
4260 tsubst_flags_t complain)
4261 {
4262 tree name;
4263 tree fn;
4265 {
4280 }
4285 flags,
4287 complain);
4288 }
4290 /* Generate a call to a destructor. TYPE is the type to cast ADDR to.
4291 ADDR is an expression which yields the store to be destroyed.
4292 AUTO_DELETE is the name of the destructor to call, i.e., either
4293 sfk_complete_destructor, sfk_base_destructor, or
4294 sfk_deleting_destructor.
4296 FLAGS is the logical disjunction of zero or more LOOKUP_
4297 flags. See cp-tree.h for more info. */
4299 tree
4302 {
4303 tree expr;
4310 /* Can happen when CURRENT_EXCEPTION_OBJECT gets its type
4311 set to `error_mark_node' before it gets properly cleaned up. */
4319 {
4321 {
4325 }
4328 }
4331 {
4334 /* We don't want to warn about delete of void*, only other
4335 incomplete types. Deleting other incomplete types
4336 invokes undefined behavior, but it is not ill-formed, so
4337 compile to something that would even do The Right Thing
4338 (TM) should the type have a trivial dtor and no delete
4339 operator. */
4341 {
4344 {
4347 "possible problem detected in invocation of "
4349 {
4352 "neither the destructor nor the class-specific "
4353 "operator delete will be called, even if they are "
4355 }
4356 }
4360 {
4361 tree dtor;
4364 {
4367 "deleting object of abstract class type %qT"
4368 " which has non-virtual destructor"
4370 else
4372 "deleting object of polymorphic class type %qT"
4373 " which has non-virtual destructor"
4375 }
4376 }
4377 }
4381 /* Throw away const and volatile on target type of addr. */
4383 }
4384 else
4385 {
4386 /* Don't check PROTECT here; leave that decision to the
4387 destructor. If the destructor is accessible, call it,
4388 else report error. */
4396 }
4399 {
4400 /* Make sure the destructor is callable. */
4402 {
4404 complain),
4408 }
4415 use_global_delete,
4418 complain);
4419 }
4420 else
4421 {
4424 tree ifexp;
4429 /* For `::delete x', we must not use the deleting destructor
4430 since then we would not be sure to get the global `operator
4431 delete'. */
4433 {
4434 /* We will use ADDR multiple times so we must save it. */
4437 /* Delete the object. */
4439 head,
4444 complain);
4445 /* Otherwise, treat this like a complete object destructor
4446 call. */
4448 }
4449 /* If the destructor is non-virtual, there is no deleting
4450 variant. Instead, we must explicitly call the appropriate
4451 `operator delete' here. */
4454 {
4455 /* We will use ADDR multiple times so we must save it. */
4457 /* Build the call. */
4459 addr,
4464 complain);
4465 /* Call the complete object destructor. */
4467 }
4470 {
4471 /* Make sure we have access to the member op delete, even though
4472 we'll actually be calling it from the destructor. */
4477 complain);
4478 }
4485 /* The delete operator must be called, regardless of whether
4486 the destructor throws.
4488 [expr.delete]/7 The deallocation function is called
4489 regardless of whether the destructor for the object or some
4490 element of the array throws an exception. */
4493 /* We need to calculate this before the dtor changes the vptr. */
4498 /* Explicit destructor call; don't check for null pointer. */
4500 else
4501 {
4502 /* Handle deleting a null pointer. */
4508 /* This is a compiler generated comparison, don't emit
4509 e.g. -Wnonnull-compare warning for it. */
4512 }
4518 }
4519 }
4521 /* At the beginning of a destructor, push cleanups that will call the
4522 destructors for our base classes and members.
4524 Called from begin_destructor_body. */
4526 void
4528 {
4531 tree member;
4532 tree expr;
4535 /* Run destructors for all virtual baseclasses. */
4538 {
4539 tree cond = (condition_conversion
4541 current_in_charge_parm,
4542 integer_two_node)));
4544 /* The CLASSTYPE_VBASECLASSES vector is in initialization
4545 order, which is also the right order for pushing cleanups. */
4548 {
4550 {
4552 base_dtor_identifier,
4553 NULL,
4554 base_binfo,
4555 (LOOKUP_NORMAL
4557 tf_warning_or_error);
4559 {
4563 }
4564 }
4565 }
4566 }
4568 /* Take care of the remaining baseclasses. */
4571 {
4577 base_dtor_identifier,
4580 tf_warning_or_error);
4583 }
4585 /* Don't automatically destroy union members. */
4591 {
4600 {
4601 tree this_member = (build_class_member_access_expr
4605 tf_warning_or_error));
4607 sfk_complete_destructor,
4612 }
4613 }
4614 }
4616 /* Build a C++ vector delete expression.
4617 MAXINDEX is the number of elements to be deleted.
4618 ELT_SIZE is the nominal size of each element in the vector.
4619 BASE is the expression that should yield the store to be deleted.
4620 This function expands (or synthesizes) these calls itself.
4621 AUTO_DELETE_VEC says whether the container (vector) should be deallocated.
4623 This also calls delete for virtual baseclasses of elements of the vector.
4625 Update: MAXINDEX is no longer needed. The size can be extracted from the
4626 start of the vector for pointers, and from the type for arrays. We still
4627 use MAXINDEX for arrays because it happens to already have one of the
4628 values we'd have to extract. (We could use MAXINDEX with pointers to
4629 confirm the size, and trap if the numbers differ; not clear that it'd
4630 be worth bothering.) */
4632 tree
4634 special_function_kind auto_delete_vec,
4636 {
4637 tree type;
4638 tree rval;
4644 {
4645 /* Step back one from start of vector, and read dimension. */
4646 tree cookie_addr;
4651 {
4654 }
4659 cookie_addr);
4661 }
4663 {
4664 /* Get the total number of things in the array, maxindex is a
4665 bad name. */
4672 {
4675 }
4676 }
4677 else
4678 {
4682 }
4690 }