| blob | bfa902050cbbed0b03168a66832bcb777e2f2f7d |
1 /* Handle initialization things in C++.
2 Copyright (C) 1987-2017 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com)
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
21 /* High-level class interface. */
49 /* We are about to generate some complex initialization code.
50 Conceptually, it is all a single expression. However, we may want
51 to include conditionals, loops, and other such statement-level
52 constructs. Therefore, we build the initialization code inside a
53 statement-expression. This function starts such an expression.
54 STMT_EXPR_P and COMPOUND_STMT_P are filled in by this function;
55 pass them back to finish_init_stmts when the expression is
56 complete. */
58 static bool
60 {
67 }
69 /* Finish out the statement-expression begun by the previous call to
70 begin_init_stmts. Returns the statement-expression itself. */
72 static tree
74 {
82 }
84 /* Constructors */
86 /* Called from initialize_vtbl_ptrs via dfs_walk. BINFO is the base
87 which we want to initialize the vtable pointer for, DATA is
88 TREE_LIST whose TREE_VALUE is the this ptr expression. */
90 static tree
92 {
97 {
101 tf_warning_or_error);
104 }
107 }
109 /* Initialize all the vtable pointers in the object pointed to by
110 ADDR. */
112 void
114 {
115 tree list;
116 tree type;
121 /* Walk through the hierarchy, initializing the vptr in each base
122 class. We do these in pre-order because we can't find the virtual
123 bases for a class until we've initialized the vtbl for that
124 class. */
126 }
128 /* Return an expression for the zero-initialization of an object with
129 type T. This expression will either be a constant (in the case
130 that T is a scalar), or a CONSTRUCTOR (in the case that T is an
131 aggregate), or NULL (in the case that T does not require
132 initialization). In either case, the value can be used as
133 DECL_INITIAL for a decl of the indicated TYPE; it is a valid static
134 initializer. If NELTS is non-NULL, and TYPE is an ARRAY_TYPE, NELTS
135 is the number of elements in the array. If STATIC_STORAGE_P is
136 TRUE, initializers are only generated for entities for which
137 zero-initialization does not simply mean filling the storage with
138 zero bytes. FIELD_SIZE, if non-NULL, is the bit size of the field,
139 subfields with bit positions at or above that bit size shouldn't
140 be added. Note that this only works when the result is assigned
141 to a base COMPONENT_REF; if we only have a pointer to the base subobject,
142 expand_assignment will end up clearing the full size of TYPE. */
144 static tree
146 tree field_size)
147 {
150 /* [dcl.init]
152 To zero-initialize an object of type T means:
154 -- if T is a scalar type, the storage is set to the value of zero
155 converted to T.
157 -- if T is a non-union class type, the storage for each nonstatic
158 data member and each base-class subobject is zero-initialized.
160 -- if T is a union type, the storage for its first data member is
161 zero-initialized.
163 -- if T is an array type, the storage for each element is
164 zero-initialized.
166 -- if T is a reference type, no initialization is performed. */
171 ;
173 /* In order to save space, we do not explicitly build initializers
174 for items that do not need them. GCC's semantics are that
175 items with static storage duration that are not otherwise
176 initialized are initialized to zero. */
177 ;
183 {
184 tree field;
187 /* Iterate over the fields, building initializations. */
189 {
196 /* Don't add virtual bases for base classes if they are beyond
197 the size of the current field, that means it is present
198 somewhere else in the object. */
200 {
205 }
207 /* Note that for class types there will be FIELD_DECLs
208 corresponding to base classes as well. Thus, iterating
209 over TYPE_FIELDs will result in correct initialization of
210 all of the subobjects. */
212 {
213 tree new_field_size
220 static_storage_p,
221 new_field_size);
224 }
226 /* For unions, only the first field is initialized. */
229 }
231 /* Build a constructor to contain the initializations. */
233 }
235 {
236 tree max_index;
239 /* Iterate over the array elements, building initializations. */
244 else
247 /* If we have an error_mark here, we should just return error mark
248 as we don't know the size of the array yet. */
253 /* A zero-sized array, which is accepted as an extension, will
254 have an upper bound of -1. */
256 {
257 constructor_elt ce;
259 /* If this is a one element array, we just use a regular init. */
262 else
264 max_index);
270 {
273 }
274 }
276 /* Build a constructor to contain the initializations. */
278 }
281 else
284 /* In all cases, the initializer is a constant. */
289 }
291 /* Return an expression for the zero-initialization of an object with
292 type T. This expression will either be a constant (in the case
293 that T is a scalar), or a CONSTRUCTOR (in the case that T is an
294 aggregate), or NULL (in the case that T does not require
295 initialization). In either case, the value can be used as
296 DECL_INITIAL for a decl of the indicated TYPE; it is a valid static
297 initializer. If NELTS is non-NULL, and TYPE is an ARRAY_TYPE, NELTS
298 is the number of elements in the array. If STATIC_STORAGE_P is
299 TRUE, initializers are only generated for entities for which
300 zero-initialization does not simply mean filling the storage with
301 zero bytes. */
303 tree
305 {
307 }
309 /* Return a suitable initializer for value-initializing an object of type
310 TYPE, as described in [dcl.init]. */
312 tree
314 {
315 /* [dcl.init]
317 To value-initialize an object of type T means:
319 - if T is a class type (clause 9) with either no default constructor
320 (12.1) or a default constructor that is user-provided or deleted,
321 then the object is default-initialized;
323 - if T is a (possibly cv-qualified) class type without a user-provided
324 or deleted default constructor, then the object is zero-initialized
325 and the semantic constraints for default-initialization are checked,
326 and if T has a non-trivial default constructor, the object is
327 default-initialized;
329 - if T is an array type, then each element is value-initialized;
331 - otherwise, the object is zero-initialized.
333 A program that calls for default-initialization or
334 value-initialization of an entity of reference type is ill-formed. */
336 /* The AGGR_INIT_EXPR tweaking below breaks in templates. */
342 {
343 tree ctor =
346 complain);
356 {
357 /* This is a class that needs constructing, but doesn't have
358 a user-provided constructor. So we need to zero-initialize
359 the object and then call the implicitly defined ctor.
360 This will be handled in simplify_aggr_init_expr. */
363 }
364 }
366 /* Discard any access checking during subobject initialization;
367 the checks are implied by the call to the ctor which we have
368 verified is OK (cpp0x/defaulted46.C). */
373 }
375 /* Like build_value_init, but don't call the constructor for TYPE. Used
376 for base initializers. */
378 tree
380 {
382 {
386 }
387 /* FIXME the class and array cases should just use digest_init once it is
388 SFINAE-enabled. */
390 {
395 {
396 tree field;
399 /* Iterate over the fields, building initializations. */
401 {
412 /* We could skip vfields and fields of types with
413 user-defined constructors, but I think that won't improve
414 performance at all; it should be simpler in general just
415 to zero out the entire object than try to only zero the
416 bits that actually need it. */
418 /* Note that for class types there will be FIELD_DECLs
419 corresponding to base classes as well. Thus, iterating
420 over TYPE_FIELDs will result in correct initialization of
421 all of the subobjects. */
430 /* We shouldn't have gotten here for anything that would need
431 non-trivial initialization, and gimplify_init_ctor_preeval
432 would need to be fixed to allow it. */
435 }
437 /* Build a constructor to contain the zero- initializations. */
439 }
440 }
442 {
445 /* Iterate over the array elements, building initializations. */
448 /* If we have an error_mark here, we should just return error mark
449 as we don't know the size of the array yet. */
451 {
454 type);
456 }
459 /* A zero-sized array, which is accepted as an extension, will
460 have an upper bound of -1. */
462 {
463 constructor_elt ce;
465 /* If this is a one element array, we just use a regular init. */
468 else
479 /* We shouldn't have gotten here for anything that would need
480 non-trivial initialization, and gimplify_init_ctor_preeval
481 would need to be fixed to allow it. */
484 }
486 /* Build a constructor to contain the initializations. */
488 }
490 {
494 }
496 {
500 }
503 }
505 /* Initialize current class with INIT, a TREE_LIST of
506 arguments for a target constructor. If TREE_LIST is void_type_node,
507 an empty initializer list was given. */
509 static void
511 {
517 tf_warning_or_error));
519 {
521 LOOKUP_NORMAL
522 |LOOKUP_NONVIRTUAL
528 }
529 }
531 /* Return the non-static data initializer for FIELD_DECL MEMBER. */
533 tree
535 {
536 tree init;
541 {
542 /* Use a PLACEHOLDER_EXPR when we don't have a 'this' parameter to
543 refer to; constexpr evaluation knows what to do with it. */
546 }
549 {
554 /* Check recursive instantiation. */
556 {
560 }
561 else
562 {
565 /* Do deferred instantiation of the NSDMI. */
566 init = (tsubst_copy_and_build
573 }
574 }
575 else
576 {
579 {
580 unparsed:
585 }
586 /* Strip redundant TARGET_EXPR so we don't need to remap it, and
587 so the aggregate init code below will see a CONSTRUCTOR. */
593 /* Now put it back so C++17 copy elision works. */
595 }
599 }
601 /* Diagnose the flexible array MEMBER if its INITializer is non-null
602 and return true if so. Otherwise return false. */
604 bool
606 {
614 /* Point at the flexible array member declaration if it's initialized
615 in-class, and at the ctor if it's initialized in a ctor member
616 initializer list. */
617 location_t loc;
619 || !current_function_decl
622 else
627 }
629 /* Initialize MEMBER, a FIELD_DECL, with INIT, a TREE_LIST of
630 arguments. If TREE_LIST is void_type_node, an empty initializer
631 list was given; if NULL_TREE no initializer was given. */
633 static void
635 {
636 tree decl;
639 /* Use the non-static data member initializer if there was no
640 mem-initializer for this field. */
647 /* Effective C++ rule 12 requires that all data members be
648 initialized. */
652 member);
654 /* Get an lvalue for the data member. */
658 tf_warning_or_error);
664 {
666 /* Handle references. */
673 member);
674 }
677 {
678 /* mem() means value-initialization. */
680 {
684 }
685 else
686 {
692 }
693 }
694 /* Deal with this here, as we will get confused if we try to call the
695 assignment op for an anonymous union. This can happen in a
696 synthesized copy constructor. */
698 {
700 {
703 }
704 }
707 /* Pre-digested NSDMI. */
710 /* { } mem-initializer. */
715 {
716 /* With references and list-initialization, we need to deal with
717 extending temporary lifetimes. 12.2p5: "A temporary bound to a
718 reference member in a constructor’s ctor-initializer (12.6.2)
719 persists until the constructor exits." */
724 tf_warning_or_error);
726 {
731 }
734 /* A FIELD_DECL doesn't really have a suitable lifetime, but
735 make_temporary_var_for_ref_to_temp will treat it as automatic and
736 set_up_extended_ref_temp wants to use the decl in a warning. */
746 }
749 {
751 {
753 {
754 /* Check to make sure the member initializer is valid and
755 something like a CONSTRUCTOR in: T a[] = { 1, 2 } and
756 if it isn't, return early to avoid triggering another
757 error below. */
763 else
768 }
772 {
774 {
775 /* Initialize the array only if it's not a flexible
776 array member (i.e., if it has an upper bound). */
780 }
781 }
782 else
784 }
785 else
786 {
793 {
794 /* TYPE_NEEDS_CONSTRUCTING can be set just because we have a
795 vtable; still give this diagnostic. */
800 }
802 tf_warning_or_error));
803 }
804 }
805 else
806 {
808 {
809 tree core_type;
810 /* member traversal: note it leaves init NULL */
812 {
817 }
819 {
824 }
834 }
836 /* There was an explicit member initialization. Do some work
837 in that case. */
839 tf_warning_or_error);
841 /* Reject a member initializer for a flexible array member. */
845 tf_warning_or_error));
846 }
849 {
850 tree expr;
855 tf_warning_or_error);
858 tf_warning_or_error);
863 }
864 }
866 /* Returns a TREE_LIST containing (as the TREE_PURPOSE of each node) all
867 the FIELD_DECLs on the TYPE_FIELDS list for T, in reverse order. */
869 static tree
871 {
872 tree fields;
874 /* Note whether or not T is a union. */
879 {
880 tree fieldtype;
882 /* Skip CONST_DECLs for enumeration constants and so forth. */
888 /* For an anonymous struct or union, we must recursively
889 consider the fields of the anonymous type. They can be
890 directly initialized from the constructor. */
892 {
893 /* Add this field itself. Synthesized copy constructors
894 initialize the entire aggregate. */
896 /* And now add the fields in the anonymous aggregate. */
899 }
900 /* Add this field. */
903 }
906 }
908 /* Return the innermost aggregate scope for FIELD, whether that is
909 the enclosing class or an anonymous aggregate within it. */
911 static tree
913 {
916 else
918 }
920 /* The MEM_INITS are a TREE_LIST. The TREE_PURPOSE of each list gives
921 a FIELD_DECL or BINFO in T that needs initialization. The
922 TREE_VALUE gives the initializer, or list of initializer arguments.
924 Return a TREE_LIST containing all of the initializations required
925 for T, in the order in which they should be performed. The output
926 list has the same format as the input. */
928 static tree
930 {
931 tree init;
933 tree sorted_inits;
934 tree next_subobject;
939 /* Build up a list of initializations. The TREE_PURPOSE of entry
940 will be the subobject (a FIELD_DECL or BINFO) to initialize. The
941 TREE_VALUE will be the constructor arguments, or NULL if no
942 explicit initialization was provided. */
945 /* Process the virtual bases. */
950 /* Process the direct bases. */
956 /* Process the non-static data members. */
958 /* Reverse the entire list of initializations, so that they are in
959 the order that they will actually be performed. */
962 /* If the user presented the initializers in an order different from
963 that in which they will actually occur, we issue a warning. Keep
964 track of the next subobject which can be explicitly initialized
965 without issuing a warning. */
968 /* Go through the explicit initializers, filling in TREE_PURPOSE in
969 the SORTED_INITS. */
971 {
972 tree subobject;
973 tree subobject_init;
977 /* If the explicit initializers are in sorted order, then
978 SUBOBJECT will be NEXT_SUBOBJECT, or something following
979 it. */
981 subobject_init;
986 /* Issue a warning if the explicit initializer order does not
987 match that which will actually occur.
988 ??? Are all these on the correct lines? */
990 {
995 else
1001 else
1005 }
1007 /* Look again, from the beginning of the list. */
1009 {
1013 }
1015 /* It is invalid to initialize the same subobject more than
1016 once. */
1018 {
1022 subobject);
1023 else
1026 subobject);
1027 }
1029 /* Record the initialization. */
1032 }
1034 /* [class.base.init]
1036 If a ctor-initializer specifies more than one mem-initializer for
1037 multiple members of the same union (including members of
1038 anonymous unions), the ctor-initializer is ill-formed.
1040 Here we also splice out uninitialized union members. */
1042 {
1046 {
1047 tree field;
1048 tree ctx;
1054 /* Skip base classes. */
1058 /* If this is an anonymous aggregate with no explicit initializer,
1059 splice it out. */
1063 /* See if this field is a member of a union, or a member of a
1064 structure contained in a union, etc. */
1067 /* If this field is not a member of a union, skip it. */
1072 /* If this union member has no explicit initializer and no NSDMI,
1073 splice it out. */
1076 else
1079 /* It's only an error if we have two initializers for the same
1080 union type. */
1082 {
1085 }
1087 /* See if LAST_FIELD and the field initialized by INIT are
1088 members of the same union (or the union itself). If so, there's
1089 a problem, unless they're actually members of the same structure
1090 which is itself a member of a union. For example, given:
1092 union { struct { int i; int j; }; };
1094 initializing both `i' and `j' makes sense. */
1095 ctx = common_enclosing_class
1101 {
1102 /* A mem-initializer hides an NSDMI. */
1107 else
1108 {
1111 ctx);
1113 }
1114 }
1118 next:
1121 splice:
1124 }
1125 }
1128 }
1130 /* Callback for cp_walk_tree to mark all PARM_DECLs in a tree as read. */
1132 static tree
1134 {
1139 }
1141 /* Initialize all bases and members of CURRENT_CLASS_TYPE. MEM_INITS
1142 is a TREE_LIST giving the explicit mem-initializer-list for the
1143 constructor. The TREE_PURPOSE of each entry is a subobject (a
1144 FIELD_DECL or a BINFO) of the CURRENT_CLASS_TYPE. The TREE_VALUE
1145 is a TREE_LIST giving the arguments to the constructor or
1146 void_type_node for an empty list of arguments. */
1148 void
1150 {
1153 /* We will already have issued an error message about the fact that
1154 the type is incomplete. */
1161 {
1162 /* Delegating constructor. */
1166 }
1172 /* Sort the mem-initializers into the order in which the
1173 initializations should be performed. */
1178 /* Initialize base classes. */
1182 {
1186 /* We already have issued an error message. */
1190 /* Suppress access control when calling the inherited ctor. */
1192 && flag_new_inheriting_ctors
1198 {
1199 /* If these initializations are taking place in a copy constructor,
1200 the base class should probably be explicitly initialized if there
1201 is a user-defined constructor in the base class (other than the
1202 default constructor, which will be called anyway). */
1210 }
1212 /* Initialize the base. */
1214 {
1215 tree base_addr;
1221 tf_warning_or_error),
1222 arguments,
1223 flags,
1224 tf_warning_or_error);
1226 }
1228 /* C++14 DR1658 Means we do not have to construct vbases of
1229 abstract classes. */
1231 else
1232 /* When not constructing vbases of abstract classes, at least mark
1233 the arguments expressions as read to avoid
1234 -Wunused-but-set-parameter false positives. */
1239 }
1242 /* Initialize the vptrs. */
1245 /* Initialize the data members. */
1247 {
1251 }
1252 }
1254 /* Returns the address of the vtable (i.e., the value that should be
1255 assigned to the vptr) for BINFO. */
1257 tree
1259 {
1261 tree vtbl;
1264 /* If this is a virtual primary base, then the vtable we want to store
1265 is that for the base this is being used as the primary base of. We
1266 can't simply skip the initialization, because we may be expanding the
1267 inits of a subobject constructor where the virtual base layout
1268 can be different. */
1272 /* Figure out what vtable BINFO's vtable is based on, and mark it as
1273 used. */
1277 /* Now compute the address to use when initializing the vptr. */
1283 }
1285 /* This code sets up the virtual function tables appropriate for
1286 the pointer DECL. It is a one-ply initialization.
1288 BINFO is the exact type that DECL is supposed to be. In
1289 multiple inheritance, this might mean "C's A" if C : A, B. */
1291 static void
1293 {
1295 tree vtt_index;
1297 /* Compute the initializer for vptr. */
1300 /* We may get this vptr from a VTT, if this is a subobject
1301 constructor or subobject destructor. */
1304 {
1305 tree vtbl2;
1306 tree vtt_parm;
1308 /* Compute the value to use, when there's a VTT. */
1314 /* The actual initializer is the VTT value only in the subobject
1315 constructor. In maybe_clone_body we'll substitute NULL for
1316 the vtt_parm in the case of the non-subobject constructor. */
1318 }
1320 /* Compute the location of the vtpr. */
1322 tf_warning_or_error),
1326 /* Assign the vtable to the vptr. */
1330 }
1332 /* If an exception is thrown in a constructor, those base classes already
1333 constructed must be destroyed. This function creates the cleanup
1334 for BINFO, which has just been constructed. If FLAG is non-NULL,
1335 it is a DECL which is nonzero when this base needs to be
1336 destroyed. */
1338 static void
1340 {
1341 tree expr;
1346 /* Call the destructor. */
1348 base_dtor_identifier,
1349 NULL,
1350 binfo,
1352 tf_warning_or_error);
1364 }
1366 /* Construct the virtual base-class VBASE passing the ARGUMENTS to its
1367 constructor. */
1369 static void
1371 {
1372 tree inner_if_stmt;
1373 tree exp;
1374 tree flag;
1376 /* If there are virtual base classes with destructors, we need to
1377 emit cleanups to destroy them if an exception is thrown during
1378 the construction process. These exception regions (i.e., the
1379 period during which the cleanups must occur) begin from the time
1380 the construction is complete to the end of the function. If we
1381 create a conditional block in which to initialize the
1382 base-classes, then the cleanup region for the virtual base begins
1383 inside a block, and ends outside of that block. This situation
1384 confuses the sjlj exception-handling code. Therefore, we do not
1385 create a single conditional block, but one for each
1386 initialization. (That way the cleanup regions always begin
1387 in the outer block.) We trust the back end to figure out
1388 that the FLAG will not change across initializations, and
1389 avoid doing multiple tests. */
1394 /* Compute the location of the virtual base. If we're
1395 constructing virtual bases, then we must be the most derived
1396 class. Therefore, we don't have to look up the virtual base;
1397 we already know where it is. */
1406 }
1408 /* Find the context in which this FIELD can be initialized. */
1410 static tree
1412 {
1415 /* Anonymous union members can be initialized in the first enclosing
1416 non-anonymous union context. */
1420 }
1422 /* Function to give error message if member initialization specification
1423 is erroneous. FIELD is the member we decided to initialize.
1424 TYPE is the type for which the initialization is being performed.
1425 FIELD must be a member of TYPE.
1427 MEMBER_NAME is the name of the member. */
1429 static int
1431 {
1435 {
1437 member_name);
1439 }
1441 {
1444 field);
1446 }
1448 {
1452 }
1454 {
1456 member_name);
1458 }
1461 }
1463 /* NAME is a FIELD_DECL, an IDENTIFIER_NODE which names a field, or it
1464 is a _TYPE node or TYPE_DECL which names a base for that type.
1465 Check the validity of NAME, and return either the base _TYPE, base
1466 binfo, or the FIELD_DECL of the member. If NAME is invalid, return
1467 NULL_TREE and issue a diagnostic.
1469 An old style unnamed direct single base construction is permitted,
1470 where NAME is NULL. */
1472 tree
1474 {
1475 tree basetype;
1476 tree field;
1482 {
1483 /* This is an obsolete unnamed base class initializer. The
1484 parser will already have warned about its use. */
1486 {
1489 current_class_type);
1492 basetype = BINFO_TYPE
1497 current_class_type);
1499 }
1500 }
1502 {
1505 }
1508 else
1512 {
1513 tree class_binfo;
1514 tree direct_binfo;
1515 tree virtual_binfo;
1526 /* Look for a direct base. */
1531 /* Look for a virtual base -- unless the direct base is itself
1532 virtual. */
1536 /* [class.base.init]
1538 If a mem-initializer-id is ambiguous because it designates
1539 both a direct non-virtual base class and an inherited virtual
1540 base class, the mem-initializer is ill-formed. */
1542 {
1544 basetype);
1546 }
1549 {
1553 else
1557 }
1560 }
1561 else
1562 {
1565 else
1570 }
1573 }
1575 /* This is like `expand_member_init', only it stores one aggregate
1576 value into another.
1578 INIT comes in two flavors: it is either a value which
1579 is to be stored in EXP, or it is a parameter list
1580 to go to a constructor, which will operate on EXP.
1581 If INIT is not a parameter list for a constructor, then set
1582 LOOKUP_ONLYCONVERTING.
1583 If FLAGS is LOOKUP_ONLYCONVERTING then it is the = init form of
1584 the initializer, if FLAGS is 0, then it is the (init) form.
1585 If `init' is a CONSTRUCTOR, then we emit a warning message,
1586 explaining that such initializations are invalid.
1588 If INIT resolves to a CALL_EXPR which happens to return
1589 something of the type we are looking for, then we know
1590 that we can safely use that call to perform the
1591 initialization.
1593 The virtual function table pointer cannot be set up here, because
1594 we do not really know its type.
1596 This never calls operator=().
1598 When initializing, nothing is CONST.
1600 A default copy constructor may have to be used to perform the
1601 initialization.
1603 A constructor or a conversion operator may have to be used to
1604 perform the initialization, but not both, as it would be ambiguous. */
1606 tree
1608 {
1609 tree stmt_expr;
1610 tree compound_stmt;
1620 location_t init_loc = (init
1628 {
1633 {
1637 {
1638 /* Wrap the initializer in a CONSTRUCTOR so that build_vec_init
1639 recognizes it as direct-initialization. */
1643 }
1644 }
1645 else
1646 {
1647 /* An array may not be initialized use the parenthesized
1648 initialization form -- unless the initializer is "()". */
1650 {
1654 }
1655 /* Must arrange to initialize each element of EXP
1656 from elements of INIT. */
1666 {
1670 else
1672 }
1673 }
1677 from_array,
1678 complain);
1682 /* Restore the type of init unless it was used directly. */
1686 }
1697 /* Just know that we've seen something for this node. */
1711 }
1713 static void
1715 tsubst_flags_t complain)
1716 {
1718 tree ctor_name;
1720 /* It fails because there may not be a constructor which takes
1721 its own type as the first (or only parameter), but which does
1722 take other types via a conversion. So, if the thing initializing
1723 the expression is a unit element of type X, first try X(X&),
1724 followed by initialization by X. If neither of these work
1725 out, then look hard. */
1726 tree rval;
1729 /* If we have direct-initialization from an initializer list, pull
1730 it out of the TREE_LIST so the code below can see it. */
1733 {
1737 /* Only call reshape_init if it has not been called earlier
1738 by the callers. */
1741 }
1745 /* A brace-enclosed initializer for an aggregate. In C++0x this can
1746 happen for direct-initialization, too. */
1749 /* A CONSTRUCTOR of the target's type is a previously digested
1750 initializer, whether that happened just above or in
1751 cp_parser_late_parsing_nsdmi.
1753 A TARGET_EXPR with TARGET_EXPR_DIRECT_INIT_P or TARGET_EXPR_LIST_INIT_P
1754 set represents the whole initialization, so we shouldn't build up
1755 another ctor call. */
1762 {
1763 /* Early initialization via a TARGET_EXPR only works for
1764 complete objects. */
1771 }
1775 {
1776 /* Base subobjects should only get direct-initialization. */
1780 /* Do nothing. We hit this in two cases: Reference initialization,
1781 where we aren't initializing a real variable, so we don't want
1782 to run a new constructor; and catching an exception, where we
1783 have already built up the constructor call so we could wrap it
1785 else
1790 /* We need to protect the initialization of a catch parm with a
1791 call to terminate(), which shows up as a MUST_NOT_THROW_EXPR
1792 around the TARGET_EXPR for the copy constructor. See
1793 initialize_handler_parm. */
1794 {
1798 }
1799 else
1804 }
1809 {
1813 }
1814 else
1819 {
1820 /* Delegating constructor. */
1821 tree complete;
1822 tree base;
1825 /* Unshare the arguments for the second call. */
1828 {
1831 }
1834 complain);
1840 complain);
1843 }
1844 else
1845 {
1848 else
1851 complain);
1852 }
1858 {
1861 {
1865 }
1866 }
1868 /* FIXME put back convert_to_void? */
1871 }
1873 /* This function is responsible for initializing EXP with INIT
1874 (if any).
1876 BINFO is the binfo of the type for who we are performing the
1877 initialization. For example, if W is a virtual base class of A and B,
1878 and C : A, B.
1879 If we are initializing B, then W must contain B's W vtable, whereas
1880 were we initializing C, W must contain C's W vtable.
1882 TRUE_EXP is nonzero if it is the true expression being initialized.
1883 In this case, it may be EXP, or may just contain EXP. The reason we
1884 need this is because if EXP is a base element of TRUE_EXP, we
1885 don't necessarily know by looking at EXP where its virtual
1886 baseclass fields should really be pointing. But we do know
1887 from TRUE_EXP. In constructors, we don't know anything about
1888 the value being initialized.
1890 FLAGS is just passed to `build_new_method_call'. See that function
1891 for its description. */
1893 static void
1895 tsubst_flags_t complain)
1896 {
1902 /* Use a function returning the desired type to initialize EXP for us.
1903 If the function is a constructor, and its first argument is
1904 NULL_TREE, know that it was meant for us--just slide exp on
1905 in and expand the constructor. Constructors now come
1906 as TARGET_EXPRs. */
1910 {
1912 /* If store_init_value returns NULL_TREE, the INIT has been
1913 recorded as the DECL_INITIAL for EXP. That means there's
1914 nothing more we have to do. */
1920 }
1922 /* List-initialization from {} becomes value-initialization for non-aggregate
1923 classes with default constructors. Handle this here when we're
1924 initializing a base, so protected access works. */
1926 {
1933 }
1935 /* If an explicit -- but empty -- initializer list was present,
1936 that's value-initialization. */
1938 {
1939 /* If the type has data but no user-provided ctor, we need to zero
1940 out the object. */
1943 {
1946 /* Don't clobber already initialized virtual bases. */
1949 field_size);
1952 }
1954 /* If we don't need to mess with the constructor at all,
1955 then we're done. */
1959 /* Otherwise fall through and call the constructor. */
1961 }
1963 /* We know that expand_default_init can handle everything we want
1964 at this point. */
1966 }
1968 /* Report an error if TYPE is not a user-defined, class type. If
1969 OR_ELSE is nonzero, give an error message. */
1971 int
1973 {
1978 {
1982 }
1984 }
1986 tree
1988 {
1994 else
1996 }
1998 /* Build a reference to a member of an aggregate. This is not a C++
1999 `&', but really something which can have its address taken, and
2000 then act as a pointer to member, for example TYPE :: FIELD can have
2001 its address taken by saying & TYPE :: FIELD. ADDRESS_P is true if
2002 this expression is the operand of "&".
2004 @@ Prints out lousy diagnostics for operator <typename>
2005 @@ fields.
2007 @@ This function should be rewritten and placed in search.c. */
2009 tree
2011 tsubst_flags_t complain)
2012 {
2013 tree decl;
2016 /* class templates can come in as TEMPLATE_DECLs here. */
2029 /* Callers should call mark_used before this point. */
2034 {
2038 }
2040 /* Entities other than non-static members need no further
2041 processing. */
2048 {
2052 }
2054 /* Set up BASEBINFO for member lookup. */
2057 /* A lot of this logic is now handled in lookup_member. */
2059 {
2060 /* Go from the TREE_BASELINK to the member function info. */
2064 {
2065 /* Get rid of a potential OVERLOAD around it. */
2068 /* Unique functions are handled easily. */
2070 /* For non-static member of base class, we need a special rule
2071 for access checking [class.protected]:
2073 If the access is to form a pointer to member, the
2074 nested-name-specifier shall name the derived class
2075 (or any class derived from that class). */
2080 complain);
2081 else
2083 complain);
2089 }
2090 else
2092 }
2094 {
2095 /* We need additional test besides the one in
2096 check_accessibility_of_qualified_id in case it is
2097 a pointer to non-static member. */
2099 complain))
2101 }
2104 {
2105 /* If MEMBER is non-static, then the program has fallen afoul of
2106 [expr.prim]:
2108 An id-expression that denotes a nonstatic data member or
2109 nonstatic member function of a class can only be used:
2111 -- as part of a class member access (_expr.ref_) in which the
2112 object-expression refers to the member's class or a class
2113 derived from that class, or
2115 -- to form a pointer to member (_expr.unary.op_), or
2117 -- in the body of a nonstatic member function of that class or
2118 of a class derived from that class (_class.mfct.nonstatic_), or
2120 -- in a mem-initializer for a constructor for that class or for
2121 a class derived from that class (_class.base.init_). */
2123 {
2124 /* Build a representation of the qualified name suitable
2125 for use as the operand to "&" -- even though the "&" is
2126 not actually present. */
2128 /* In Microsoft mode, treat a non-static member function as if
2129 it were a pointer-to-member. */
2131 {
2134 }
2139 }
2141 {
2145 }
2147 }
2152 }
2154 /* If DECL is a scalar enumeration constant or variable with a
2155 constant initializer, return the initializer (or, its initializers,
2156 recursively); otherwise, return DECL. If STRICT_P, the
2157 initializer is only returned if DECL is a
2158 constant-expression. If RETURN_AGGREGATE_CST_OK_P, it is ok to
2159 return an aggregate constant. */
2161 static tree
2163 {
2168 {
2169 tree init;
2170 /* If DECL is a static data member in a template
2171 specialization, we must instantiate it here. The
2172 initializer for the static data member is not processed
2173 until needed; we need it now. */
2178 {
2181 /* Treat the error as a constant to avoid cascading errors on
2182 excessively recursive template instantiation (c++/9335). */
2184 else
2186 }
2187 /* Initializers in templates are generally expanded during
2188 instantiation, so before that for const int i(2)
2189 INIT is a TREE_LIST with the actual initializer as
2190 TREE_VALUE. */
2192 && init
2196 /* Instantiate a non-dependent initializer for user variables. We
2197 mustn't do this for the temporary for an array compound literal;
2198 trying to instatiate the initializer will keep creating new
2199 temporaries until we crash. Probably it's not useful to do it for
2200 other artificial variables, either. */
2206 || (!return_aggregate_cst_ok_p
2207 /* Unless RETURN_AGGREGATE_CST_OK_P is true, do not
2208 return an aggregate constant (of which string
2209 literals are a special case), as we do not want
2210 to make inadvertent copies of such entities, and
2211 we must be sure that their addresses are the
2212 same everywhere. */
2216 /* Don't return a CONSTRUCTOR for a variable with partial run-time
2217 initialization, since it doesn't represent the entire value. */
2221 /* If the variable has a dynamic initializer, don't use its
2222 DECL_INITIAL which doesn't reflect the real value. */
2229 }
2231 }
2233 /* If DECL is a CONST_DECL, or a constant VAR_DECL initialized by constant
2234 of integral or enumeration type, or a constexpr variable of scalar type,
2235 then return that value. These are those variables permitted in constant
2236 expressions by [5.19/1]. */
2238 tree
2240 {
2243 }
2245 /* Like scalar_constant_value, but can also return aggregate initializers. */
2247 tree
2249 {
2252 }
2254 /* A more relaxed version of scalar_constant_value, used by the
2255 common C/C++ code. */
2257 tree
2259 {
2262 }
2263 \f
2264 /* Common subroutines of build_new and build_vec_delete. */
2265 \f
2266 /* Build and return a NEW_EXPR. If NELTS is non-NULL, TYPE[NELTS] is
2267 the type of the object being allocated; otherwise, it's just TYPE.
2268 INIT is the initializer, if any. USE_GLOBAL_NEW is true if the
2269 user explicitly wrote "::operator new". PLACEMENT, if non-NULL, is
2270 a vector of arguments to be provided as arguments to a placement
2271 new operator. This routine performs no semantic checks; it just
2272 creates and returns a NEW_EXPR. */
2274 static tree
2277 {
2278 tree init_list;
2279 tree new_expr;
2281 /* If INIT is NULL, the we want to store NULL_TREE in the NEW_EXPR.
2282 If INIT is not NULL, then we want to store VOID_ZERO_NODE. This
2283 permits us to distinguish the case of a missing initializer "new
2284 int" from an empty initializer "new int()". */
2289 else
2294 init_list);
2299 }
2301 /* Diagnose uninitialized const members or reference members of type
2302 TYPE. USING_NEW is used to disambiguate the diagnostic between a
2303 new expression without a new-initializer and a declaration. Returns
2304 the error count. */
2306 static int
2309 {
2310 tree field;
2317 {
2318 tree field_type;
2329 {
2332 {
2334 {
2338 else
2340 }
2341 else
2342 {
2347 else
2350 }
2353 }
2354 }
2357 {
2360 {
2362 {
2366 else
2368 }
2369 else
2370 {
2375 else
2378 }
2381 }
2382 }
2385 error_count
2388 }
2390 }
2392 int
2394 {
2396 }
2398 /* Call __cxa_bad_array_new_length to indicate that the size calculation
2399 overflowed. Pretend it returns sizetype so that it plays nicely in the
2400 COND_EXPR. */
2402 tree
2404 {
2408 NULL_TREE));
2411 }
2413 /* Attempt to find the initializer for field T in the initializer INIT,
2414 when non-null. Returns the initializer when successful and NULL
2415 otherwise. */
2416 static tree
2418 {
2425 /* Iterate over all top-level initializer elements. */
2427 {
2428 /* If the member T is found, return it. */
2432 /* Otherwise continue and/or recurse into nested initializers. */
2436 }
2438 }
2440 /* Attempt to verify that the argument, OPER, of a placement new expression
2441 refers to an object sufficiently large for an object of TYPE or an array
2442 of NELTS of such objects when NELTS is non-null, and issue a warning when
2443 it does not. SIZE specifies the size needed to construct the object or
2444 array and captures the result of NELTS * sizeof (TYPE). (SIZE could be
2445 greater when the array under construction requires a cookie to store
2446 NELTS. GCC's placement new expression stores the cookie when invoking
2447 a user-defined placement new operator function but not the default one.
2448 Placement new expressions with user-defined placement new operator are
2449 not diagnosed since we don't know how they use the buffer (this could
2450 be a future extension). */
2451 static void
2453 {
2456 /* The number of bytes to add to or subtract from the size of the provided
2457 buffer based on an offset into an array or an array element reference.
2458 Although intermediate results may be negative (as in a[3] - 2) the final
2459 result cannot be. */
2461 /* True when the size of the entire destination object should be used
2462 to compute the possibly optimistic estimate of the available space. */
2464 /* True when the reference to the destination buffer is an ADDR_EXPR. */
2469 /* Using a function argument or a (non-array) variable as an argument
2470 to placement new is not checked since it's unknown what it might
2471 point to. */
2477 /* Evaluate any constant expressions. */
2480 /* Handle the common case of array + offset expression when the offset
2481 is a constant. */
2483 {
2484 /* If the offset is comple-time constant, use it to compute a more
2485 accurate estimate of the size of the buffer. Since the operand
2486 of POINTER_PLUS_EXPR is represented as an unsigned type, convert
2487 it to signed first.
2488 Otherwise, use the size of the entire array as an optimistic
2489 estimate (this may lead to false negatives). */
2493 else
2499 }
2504 {
2507 }
2513 {
2514 /* Similar to the offset computed above, see if the array index
2515 is a compile-time constant. If so, and unless the offset was
2516 not a compile-time constant, use the index to determine the
2517 size of the buffer. Otherwise, use the entire array as
2518 an optimistic estimate of the size. */
2522 else
2523 {
2526 }
2529 }
2531 /* Refers to the declared object that constains the subobject referenced
2532 by OPER. When the object is initialized, makes it possible to determine
2533 the actual size of a flexible array member used as the buffer passed
2534 as OPER to placement new. */
2536 /* True when operand is a COMPONENT_REF, to distinguish flexible array
2537 members from arrays of unspecified size. */
2540 /* Descend into a struct or union to find the member whose address
2541 is being used as the argument. */
2543 {
2549 }
2555 {
2556 /* A possibly optimistic estimate of the number of bytes available
2557 in the destination buffer. */
2559 /* True when the estimate above is in fact the exact size
2560 of the destination buffer rather than an estimate. */
2563 /* Treat members of unions and members of structs uniformly, even
2564 though the size of a member of a union may be viewed as extending
2565 to the end of the union itself (it is by __builtin_object_size). */
2569 {
2570 /* Use the size of the entire array object when the expression
2571 refers to a variable or its size depends on an expression
2572 that's not a compile-time constant. */
2575 }
2578 {
2579 /* Use the size of the type of the destination buffer object
2580 as the optimistic estimate of the available space in it. */
2582 }
2584 {
2585 /* Constructing into a buffer provided by the flexible array
2586 member of a declared object (which is permitted as a G++
2587 extension). If the array member has been initialized,
2588 determine its size from the initializer. Otherwise,
2589 the array size is zero. */
2594 }
2595 else
2596 {
2597 /* Bail if neither the size of the object nor its type is known. */
2599 }
2604 {
2605 /* Avoid diagnosing flexible array members (which are accepted
2606 as an extension and diagnosed with -Wpedantic) and zero-length
2607 arrays (also an extension).
2608 Overflowing construction in one-element arrays is diagnosed
2609 only at level 2. */
2617 && !var_decl
2620 }
2622 /* The size of the buffer can only be adjusted down but not up. */
2625 /* Reduce the size of the buffer by the adjustment computed above
2626 from the offset and/or the index into the array. */
2629 else
2632 /* The minimum amount of space needed for the allocation. This
2633 is an optimistic estimate that makes it possible to detect
2634 placement new invocation for some undersize buffers but not
2635 others. */
2645 else
2646 {
2647 /* The type is a VLA. */
2649 }
2652 {
2656 exact_size ?
2657 "placement new constructing an object of type "
2658 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2659 "and size %qwi"
2661 "%<%T [%wu]%> and size %qwu in a region of type %qT "
2665 bytes_avail);
2666 else
2668 exact_size ?
2669 "placement new constructing an array of objects "
2670 "of type %qT and size %qwu in a region of type %qT "
2671 "and size %qwi"
2673 "of type %qT and size %qwu in a region of type %qT "
2676 bytes_avail);
2677 else
2679 exact_size ?
2680 "placement new constructing an object of type %qT "
2681 "and size %qwu in a region of type %qT and size %qwi"
2683 "and size %qwu in a region of type %qT and size "
2686 bytes_avail);
2687 }
2688 }
2689 }
2691 /* True if alignof(T) > __STDCPP_DEFAULT_NEW_ALIGNMENT__. */
2693 bool
2695 {
2698 }
2700 /* Return the alignment we expect malloc to guarantee. This should just be
2701 MALLOC_ABI_ALIGNMENT, but that macro defaults to only BITS_PER_WORD for some
2702 reason, so don't let the threshold be smaller than max_align_t_align. */
2704 unsigned
2706 {
2708 }
2710 /* Determine whether an allocation function is a namespace-scope
2711 non-replaceable placement new function. See DR 1748.
2712 TODO: Enable in all standard modes. */
2713 static bool
2715 {
2717 {
2722 }
2724 }
2726 /* Generate code for a new-expression, including calling the "operator
2727 new" function, initializing the object, and, if an exception occurs
2728 during construction, cleaning up. The arguments are as for
2729 build_raw_new_expr. This may change PLACEMENT and INIT.
2730 TYPE is the type of the object being constructed, possibly an array
2731 of NELTS elements when NELTS is non-null (in "new T[NELTS]", T may
2732 be an array of the form U[inner], with the whole expression being
2733 "new U[NELTS][inner]"). */
2735 static tree
2738 tsubst_flags_t complain)
2739 {
2741 /* True iff this is a call to "operator new[]" instead of just
2742 "operator new". */
2744 /* If ARRAY_P is true, the element type of the array. This is never
2745 an ARRAY_TYPE; for something like "new int[3][4]", the
2746 ELT_TYPE is "int". If ARRAY_P is false, this is the same type as
2747 TYPE. */
2748 tree elt_type;
2749 /* The type of the new-expression. (This type is always a pointer
2750 type.) */
2751 tree pointer_type;
2752 tree non_const_pointer_type;
2753 /* The most significant array bound in int[OUTER_NELTS][inner]. */
2755 /* For arrays with a non-constant number of elements, a bounds checks
2756 on the NELTS parameter to avoid integer overflow at runtime. */
2759 /* Number of the "inner" elements in "new T[OUTER_NELTS][inner]". */
2762 /* Size of the inner array elements (those with constant dimensions). */
2763 offset_int inner_size;
2764 /* The address returned by the call to "operator new". This node is
2765 a VAR_DECL and is therefore reusable. */
2766 tree alloc_node;
2767 tree alloc_fn;
2770 /* If non-NULL, the number of extra bytes to allocate at the
2771 beginning of the storage allocated for an array-new expression in
2772 order to store the number of elements. */
2774 tree placement_first;
2776 /* True if the function we are calling is a placement allocation
2777 function. */
2779 /* True if the storage must be initialized, either by a constructor
2780 or due to an explicit new-initializer. */
2782 /* The address of the thing allocated, not including any cookie. In
2783 particular, if an array cookie is in use, DATA_ADDR is the
2784 address of the first array element. This node is a VAR_DECL, and
2785 is therefore reusable. */
2786 tree data_addr;
2791 {
2794 }
2796 {
2797 /* Transforms new (T[N]) to new T[N]. The former is a GNU
2798 extension for variable N. (This also covers new T where T is
2799 a VLA typedef.) */
2805 }
2807 /* Lots of logic below. depends on whether we have a constant number of
2808 elements, so go ahead and fold it now. */
2812 /* If our base type is an array, then make sure we know how many elements
2813 it has. */
2817 {
2821 {
2826 {
2830 }
2832 }
2833 else
2834 {
2836 {
2840 }
2842 }
2846 inner_nelts_cst,
2847 complain);
2848 }
2851 {
2854 }
2859 /* Warn if we performed the (T[N]) to T[N] transformation and N is
2860 variable. */
2863 {
2865 {
2872 }
2873 else
2875 }
2878 {
2882 }
2890 {
2892 /* A program that calls for default-initialization [...] of an
2893 entity of reference type is ill-formed. */
2897 /* A new-expression that creates an object of type T initializes
2898 that object as follows:
2899 - If the new-initializer is omitted:
2900 -- If T is a (possibly cv-qualified) non-POD class type
2901 (or array thereof), the object is default-initialized (8.5).
2902 [...]
2903 -- Otherwise, the object created has indeterminate
2904 value. If T is a const-qualified type, or a (possibly
2905 cv-qualified) POD class type (or array thereof)
2906 containing (directly or indirectly) a member of
2907 const-qualified type, the program is ill-formed; */
2917 }
2921 {
2925 }
2929 {
2930 /* Maximum available size in bytes. Half of the address space
2931 minus the cookie size. */
2932 offset_int max_size
2934 /* Maximum number of outer elements which can be allocated. */
2935 offset_int max_outer_nelts;
2936 tree max_outer_nelts_tree;
2942 /* Unconditionally subtract the cookie size. This decreases the
2943 maximum object size and is safe even if we choose not to use
2944 a cookie after all. */
2950 {
2954 }
2962 {
2964 {
2965 /* When the array size is constant, check it at compile time
2966 to make sure it doesn't exceed the implementation-defined
2967 maximum, as required by C++ 14 (in C++ 11 this requirement
2968 isn't explicitly stated but it's enforced anyway -- see
2969 grokdeclarator in cp/decl.c). */
2973 }
2974 }
2975 else
2976 {
2977 /* When a runtime check is necessary because the array size
2978 isn't constant, keep only the top-most seven bits (starting
2979 with the most significant non-zero bit) of the maximum size
2980 to compare the array size against, to simplify encoding the
2981 constant maximum size in the instruction stream. */
2988 outer_nelts,
2989 max_outer_nelts_tree);
2990 }
2991 }
2999 /* If PLACEMENT is a single simple pointer type not passed by
3000 reference, prepare to capture it in a temporary variable. Do
3001 this now, since PLACEMENT will change in the calls below. */
3009 /* Allocate the object. */
3010 tree fnname;
3011 tree fns;
3015 member_new_p = !globally_qualified_p
3017 && (array_p
3022 {
3023 /* Use a class-specific operator new. */
3024 /* If a cookie is required, add some extra space. */
3027 else
3028 {
3030 /* No size arithmetic necessary, so the size check is
3031 not needed. */
3034 }
3035 /* Perform the overflow check. */
3042 /* Create the argument list. */
3044 /* Do name-lookup to find the appropriate operator. */
3047 {
3051 }
3053 {
3055 {
3058 }
3060 }
3064 {
3067 alloc_call
3071 /* If no matching function is found and the allocated object type
3072 has new-extended alignment, the alignment argument is removed
3073 from the argument list, and overload resolution is performed
3074 again. */
3077 }
3081 LOOKUP_NORMAL,
3083 }
3084 else
3085 {
3086 /* Use a global operator new. */
3087 /* See if a cookie might be required. */
3089 {
3091 /* No size arithmetic necessary, so the size check is
3092 not needed. */
3095 }
3101 }
3108 /* Now, check to see if this function is actually a placement
3109 allocation function. This can happen even when PLACEMENT is NULL
3110 because we might have something like:
3112 struct S { void* operator new (size_t, int i = 0); };
3114 A call to `new S' will get this allocation function, even though
3115 there is no explicit placement argument. If there is more than
3116 one argument, or there are variable arguments, then this is a
3117 placement allocation function. */
3118 placement_allocation_fn_p
3123 && !placement_allocation_fn_p
3128 {
3136 }
3138 /* If we found a simple case of PLACEMENT_EXPR above, then copy it
3139 into a temporary variable. */
3145 {
3151 {
3155 }
3159 {
3160 /* Attempt to make the warning point at the operator new argument. */
3165 }
3166 }
3168 /* In the simple case, we can stop now. */
3173 /* Store the result of the allocation call in a variable so that we can
3174 use it more than once. */
3178 /* Strip any COMPOUND_EXPRs from ALLOC_CALL. */
3182 /* Preevaluate the placement args so that we don't reevaluate them for a
3183 placement delete. */
3185 {
3186 tree inits;
3190 alloc_expr);
3191 }
3193 /* unless an allocation function is declared with an empty excep-
3194 tion-specification (_except.spec_), throw(), it indicates failure to
3195 allocate storage by throwing a bad_alloc exception (clause _except_,
3196 _lib.bad.alloc_); it returns a non-null pointer otherwise If the allo-
3197 cation function is declared with an empty exception-specification,
3198 throw(), it returns null to indicate failure to allocate storage and a
3199 non-null pointer otherwise.
3201 So check for a null exception spec on the op new we just called. */
3204 check_new
3208 {
3209 tree cookie;
3210 tree cookie_ptr;
3211 tree size_ptr_type;
3213 /* Adjust so we're pointing to the start of the object. */
3216 /* Store the number of bytes allocated so that we can know how
3217 many elements to destroy later. We use the last sizeof
3218 (size_t) bytes to store the number of elements. */
3229 {
3230 /* Also store the element size. */
3241 }
3242 }
3243 else
3244 {
3247 }
3249 /* Now use a pointer to the type we've actually allocated. */
3251 /* But we want to operate on a non-const version to start with,
3252 since we'll be modifying the elements. */
3253 non_const_pointer_type = build_pointer_type
3257 /* Any further uses of alloc_node will want this type, too. */
3260 /* Now initialize the allocated object. Note that we preevaluate the
3261 initialization expression, apart from the actual constructor call or
3262 assignment--we do this because we want to delay the allocation as long
3263 as possible in order to minimize the size of the exception region for
3264 placement delete. */
3266 {
3271 {
3274 }
3277 {
3278 /* build_value_init doesn't work in templates, and we don't need
3279 the initializer anyway since we're going to throw it away and
3280 rebuild it at instantiation time, so just build up a single
3281 constructor call to get any appropriate diagnostics. */
3285 complete_ctor_identifier,
3287 LOOKUP_NORMAL,
3288 complain);
3290 }
3292 {
3296 {
3300 else
3301 {
3305 complain);
3306 else
3307 /* We'll check the length at runtime. */
3311 }
3312 }
3314 {
3318 else
3321 }
3322 init_expr
3326 integer_one_node,
3327 complain),
3328 vecinit,
3329 explicit_value_init_p,
3331 complain);
3333 /* An array initialization is stable because the initialization
3334 of each element is a full-expression, so the temporaries don't
3335 leak out. */
3337 }
3338 else
3339 {
3343 {
3345 complete_ctor_identifier,
3347 LOOKUP_NORMAL,
3348 complain);
3349 }
3351 {
3352 /* Something like `new int()'. NO_CLEANUP is needed so
3353 we don't try and build a (possibly ill-formed)
3354 destructor. */
3359 }
3360 else
3361 {
3362 tree ie;
3364 /* We are processing something like `new int (10)', which
3365 means allocate an int, and initialize it with 10. */
3368 complain);
3371 }
3372 /* If the initializer uses C++14 aggregate NSDMI that refer to the
3373 object being initialized, replace them now and don't try to
3374 preevaluate. */
3382 stable = (!had_placeholder
3384 }
3389 /* If any part of the object initialization terminates by throwing an
3390 exception and a suitable deallocation function can be found, the
3391 deallocation function is called to free the memory in which the
3392 object was being constructed, after which the exception continues
3393 to propagate in the context of the new-expression. If no
3394 unambiguous matching deallocation function can be found,
3395 propagating the exception does not cause the object's memory to be
3396 freed. */
3398 {
3400 tree cleanup;
3402 /* The Standard is unclear here, but the right thing to do
3403 is to use the same method for finding deallocation
3404 functions that we use for finding allocation functions. */
3405 cleanup = (build_op_delete_call
3407 alloc_node,
3408 size,
3409 globally_qualified_p,
3411 alloc_fn,
3412 complain));
3417 /* This is much simpler if we were able to preevaluate all of
3418 the arguments to the constructor call. */
3419 {
3420 /* CLEANUP is compiler-generated, so no diagnostics. */
3424 /* Likewise, this try-catch is compiler-generated. */
3426 }
3427 else
3428 /* Ack! First we allocate the memory. Then we set our sentry
3429 variable to true, and expand a cleanup that deletes the
3430 memory if sentry is true. Then we run the constructor, and
3431 finally clear the sentry.
3433 We need to do this because we allocate the space first, so
3434 if there are any temporaries with cleanups in the
3435 constructor args and we weren't able to preevaluate them, we
3436 need this EH region to extend until end of full-expression
3437 to preserve nesting. */
3438 {
3446 /* CLEANUP is compiler-generated, so no diagnostics. */
3456 init_expr
3459 end));
3460 /* Likewise, this is compiler-generated. */
3462 }
3463 }
3464 }
3465 else
3468 /* Now build up the return value in reverse order. */
3478 /* If we don't have an initializer or a cookie, strip the TARGET_EXPR
3479 and return the call (which doesn't need to be adjusted). */
3481 else
3482 {
3484 {
3487 nullptr_node,
3488 complain);
3491 }
3493 /* Perform the allocation before anything else, so that ALLOC_NODE
3494 has been initialized before we start using it. */
3496 }
3501 /* A new-expression is never an lvalue. */
3505 }
3507 /* Generate a representation for a C++ "new" expression. *PLACEMENT
3508 is a vector of placement-new arguments (or NULL if none). If NELTS
3509 is NULL, TYPE is the type of the storage to be allocated. If NELTS
3510 is not NULL, then this is an array-new allocation; TYPE is the type
3511 of the elements in the array and NELTS is the number of elements in
3512 the array. *INIT, if non-NULL, is the initializer for the new
3513 object, or an empty vector to indicate an initializer of "()". If
3514 USE_GLOBAL_NEW is true, then the user explicitly wrote "::new"
3515 rather than just "new". This may change PLACEMENT and INIT. */
3517 tree
3520 {
3521 tree rval;
3530 /* Don't do auto deduction where it might affect mangling. */
3532 {
3535 {
3538 {
3541 }
3543 }
3544 }
3547 {
3554 use_global_new);
3559 {
3561 /* Also copy any CONSTRUCTORs in *init, since reshape_init and
3562 digest_init clobber them in place. */
3564 {
3568 }
3569 }
3575 }
3578 {
3580 {
3583 else
3585 }
3587 /* Try to determine the constant value only for the purposes
3588 of the diagnostic below but continue to use the original
3589 value and handle const folding later. */
3592 /* The expression in a noptr-new-declarator is erroneous if it's of
3593 non-class type and its value before converting to std::size_t is
3594 less than zero. ... If the expression is a constant expression,
3595 the program is ill-fomed. */
3598 {
3602 }
3606 }
3608 /* ``A reference cannot be created by the new operator. A reference
3609 is not an object (8.2.2, 8.4.3), so a pointer to it could not be
3610 returned by new.'' ARM 5.3.3 */
3612 {
3615 else
3618 }
3621 {
3625 }
3627 /* The type allocated must be complete. If the new-type-id was
3628 "T[N]" then we are just checking that "T" is complete here, but
3629 that is equivalent, since the value of "N" doesn't matter. */
3638 {
3644 }
3646 /* Wrap it in a NOP_EXPR so warn_if_unused_value doesn't complain. */
3651 }
3652 \f
3653 static tree
3655 special_function_kind auto_delete_vec,
3657 {
3658 tree virtual_size;
3660 tree size_exp;
3662 /* Temporary variables used by the loop. */
3665 /* This is the body of the loop that implements the deletion of a
3666 single element, and moves temp variables to next elements. */
3667 tree body;
3669 /* This is the LOOP_EXPR that governs the deletion of the elements. */
3672 /* This is the thing that governs what to do after the loop has run. */
3675 /* This is the BIND_EXPR which holds the outermost iterator of the
3676 loop. It is convenient to set this variable up and test it before
3677 executing any other code in the loop.
3678 This is also the containing expression returned by this function. */
3680 tree tmp;
3682 /* We should only have 1-D arrays here. */
3689 {
3692 "possible problem detected in invocation of "
3694 {
3697 "class-specific operator delete [] will be called, "
3699 }
3700 /* This size won't actually be used. */
3703 }
3710 {
3711 /* Make sure the destructor is callable. */
3713 {
3716 complain);
3719 }
3721 }
3723 /* The below is short by the cookie size. */
3728 tbase_init
3732 base),
3733 virtual_size),
3734 complain);
3752 complain);
3760 no_destructor:
3761 /* Delete the storage if appropriate. */
3763 {
3764 tree base_tbd;
3766 /* The below is short by the cookie size. */
3771 /* no header */
3773 else
3774 {
3775 tree cookie_size;
3779 MINUS_EXPR,
3782 cookie_size,
3783 complain);
3787 /* True size with header. */
3789 }
3796 complain);
3797 }
3801 ;
3804 else
3805 /* The delete operator mist be called, even if a destructor
3806 throws. */
3812 /* Outermost wrapper: If pointer is null, punt. */
3815 /* This is a compiler generated comparison, don't emit
3816 e.g. -Wnonnull-compare warning for it. */
3824 {
3827 }
3830 /* Pre-evaluate the SAVE_EXPR outside of the BIND_EXPR. */
3834 }
3836 /* Create an unnamed variable of the indicated TYPE. */
3838 tree
3840 {
3841 tree decl;
3851 }
3853 /* Create a new temporary variable of the indicated TYPE, initialized
3854 to INIT.
3856 It is not entered into current_binding_level, because that breaks
3857 things when it comes time to do final cleanups (which take place
3858 "outside" the binding contour of the function). */
3860 tree
3862 {
3863 tree decl;
3872 }
3874 /* Subroutine of build_vec_init. Returns true if assigning to an array of
3875 INNER_ELT_TYPE from INIT is trivial. */
3877 static bool
3879 {
3884 }
3886 /* Subroutine of build_vec_init: Check that the array has at least N
3887 elements. Other parameters are local variables in build_vec_init. */
3889 void
3891 {
3894 {
3896 {
3898 nelts);
3902 }
3903 /* Don't check an array new when -fno-exceptions. */
3904 }
3907 {
3908 /* Make sure the last element of the initializer is in bounds. */
3909 finish_expr_stmt
3910 (ubsan_instrument_bounds
3912 }
3913 }
3915 /* `build_vec_init' returns tree structure that performs
3916 initialization of a vector of aggregate types.
3918 BASE is a reference to the vector, of ARRAY_TYPE, or a pointer
3919 to the first element, of POINTER_TYPE.
3920 MAXINDEX is the maximum index of the array (one less than the
3921 number of elements). It is only used if BASE is a pointer or
3922 TYPE_DOMAIN (TREE_TYPE (BASE)) == NULL_TREE.
3924 INIT is the (possibly NULL) initializer.
3926 If EXPLICIT_VALUE_INIT_P is true, then INIT must be NULL. All
3927 elements in the array are value-initialized.
3929 FROM_ARRAY is 0 if we should init everything with INIT
3930 (i.e., every element initialized from INIT).
3931 FROM_ARRAY is 1 if we should index into INIT in parallel
3932 with initialization of DECL.
3933 FROM_ARRAY is 2 if we should index into INIT in parallel,
3934 but use assignment instead of initialization. */
3936 tree
3940 {
3941 tree rval;
3944 tree iterator;
3945 /* The type of BASE. */
3947 /* The type of an element in the array. */
3949 /* The element type reached after removing all outer array
3950 types. */
3951 tree inner_elt_type;
3952 /* The type of a pointer to an element in the array. */
3953 tree ptype;
3954 tree stmt_expr;
3955 tree compound_stmt;
3978 /* Look through the TARGET_EXPR around a compound literal. */
3987 {
3990 {
3993 }
3994 }
3996 /* If we have a braced-init-list or string constant, make sure that the array
3997 is big enough for all the initializers. */
4012 || (same_type_ignoring_top_level_qualifiers_p
4014 /* Don't do this if the CONSTRUCTOR might contain something
4015 that might throw and require us to clean up. */
4019 {
4020 /* Do non-default initialization of trivial arrays resulting from
4021 brace-enclosed initializers. In this case, digest_init and
4022 store_constructor will handle the semantics for us. */
4028 }
4034 {
4040 }
4041 else
4044 /* The code we are generating looks like:
4045 ({
4046 T* t1 = (T*) base;
4047 T* rval = t1;
4048 ptrdiff_t iterator = maxindex;
4049 try {
4050 for (; iterator != -1; --iterator) {
4051 ... initialize *t1 ...
4052 ++t1;
4053 }
4054 } catch (...) {
4055 ... destroy elements that were constructed ...
4056 }
4057 rval;
4058 })
4060 We can omit the try and catch blocks if we know that the
4061 initialization will never throw an exception, or if the array
4062 elements do not have destructors. We can omit the loop completely if
4063 the elements of the array do not have constructors.
4065 We actually wrap the entire body of the above in a STMT_EXPR, for
4066 tidiness.
4068 When copying from array to another, when the array elements have
4069 only trivial copy constructors, we should use __builtin_memcpy
4070 rather than generating a loop. That way, we could take advantage
4071 of whatever cleverness the back end has for dealing with copies
4072 of blocks of memory. */
4081 /* If initializing one array from another, initialize element by
4082 element. We rely upon the below calls to do the argument
4083 checking. Evaluate the initializer before entering the try block. */
4085 {
4094 }
4096 /* Protect the entire array initialization so that we can destroy
4097 the partially constructed array if an exception is thrown.
4098 But don't do this if we're assigning. */
4101 {
4103 }
4105 /* Should we try to create a constant initializer? */
4109 : (type_has_constexpr_default_constructor
4115 /* If we're initializing a static array, we want to do static
4116 initialization of any elements with constant initializers even if
4117 some are non-constant. */
4123 /* Skip over the handling of non-empty init lists. */
4126 /* Maybe pull out constant value when from_array? */
4129 {
4130 /* Do non-default initialization of non-trivial arrays resulting from
4131 brace-enclosed initializers. */
4134 /* If the constructor already has the array type, it's been through
4135 digest_init, so we shouldn't try to do anything more. */
4146 {
4148 tree one_init;
4150 num_initialized_elts++;
4157 else
4163 {
4166 {
4170 else
4172 }
4173 else
4174 {
4176 {
4181 }
4183 }
4184 }
4191 complain);
4194 else
4198 complain);
4201 else
4203 }
4205 /* Any elements without explicit initializers get T{}. */
4207 }
4209 {
4210 /* Check that the array is at least as long as the string. */
4217 /* Copy the string to the first part of the array. */
4223 /* Adjust the counter and pointer. */
4232 /* And set the rest of the array to NUL. */
4235 }
4237 {
4242 {
4246 }
4247 }
4249 /* Now, default-initialize any remaining elements. We don't need to
4250 do that if a) the type does not need constructing, or b) we've
4251 already initialized all the elements.
4253 We do need to keep going if we're copying an array. */
4256 /* With a constexpr default constructor, which we checked for when
4257 setting try_const above, default-initialization is equivalent to
4258 value-initialization, and build_value_init gives us something more
4259 friendly to maybe_constant_init. */
4264 && (num_initialized_elts
4266 {
4267 /* If the ITERATOR is lesser or equal to -1, then we don't have to loop;
4268 we've already initialized all the elements. */
4269 tree for_stmt;
4270 tree elt_init;
4271 tree to;
4279 complain);
4286 /* If the initializer is {}, then all elements are initialized from T{}.
4287 But for non-classes, that's the same as value-initialization. */
4289 {
4291 {
4293 }
4294 else
4295 {
4298 }
4299 }
4302 {
4303 tree from;
4306 {
4312 }
4313 else
4323 complain);
4324 else
4326 }
4328 {
4330 sorry
4334 explicit_value_init_p,
4336 }
4338 {
4342 }
4343 else
4344 {
4348 else
4349 {
4352 complain);
4354 }
4355 }
4361 {
4362 /* FIXME refs to earlier elts */
4365 {
4367 /* Don't fill the CONSTRUCTOR with zeros. */
4371 }
4372 else
4373 {
4377 else
4379 }
4382 {
4385 {
4388 }
4389 }
4390 }
4398 complain));
4401 complain));
4404 }
4406 /* Make sure to cleanup any partially constructed elements. */
4409 {
4410 tree e;
4413 complain);
4415 /* Flatten multi-dimensional array since build_vec_delete only
4416 expects one-dimensional array. */
4420 /* Avoid mixing signed and unsigned. */
4423 complain);
4432 }
4434 /* The value of the array initialization is the array itself, RVAL
4435 is a pointer to the first element. */
4446 {
4448 {
4451 }
4454 else
4456 }
4458 /* Now make the result have the correct type. */
4460 {
4465 }
4468 }
4470 /* Call the DTOR_KIND destructor for EXP. FLAGS are as for
4471 build_delete. */
4473 static tree
4475 tsubst_flags_t complain)
4476 {
4477 tree name;
4478 tree fn;
4480 {
4495 }
4500 flags,
4502 complain);
4503 }
4505 /* Generate a call to a destructor. TYPE is the type to cast ADDR to.
4506 ADDR is an expression which yields the store to be destroyed.
4507 AUTO_DELETE is the name of the destructor to call, i.e., either
4508 sfk_complete_destructor, sfk_base_destructor, or
4509 sfk_deleting_destructor.
4511 FLAGS is the logical disjunction of zero or more LOOKUP_
4512 flags. See cp-tree.h for more info. */
4514 tree
4517 {
4518 tree expr;
4525 /* Can happen when CURRENT_EXCEPTION_OBJECT gets its type
4526 set to `error_mark_node' before it gets properly cleaned up. */
4534 {
4536 {
4540 }
4543 }
4546 {
4549 /* We don't want to warn about delete of void*, only other
4550 incomplete types. Deleting other incomplete types
4551 invokes undefined behavior, but it is not ill-formed, so
4552 compile to something that would even do The Right Thing
4553 (TM) should the type have a trivial dtor and no delete
4554 operator. */
4556 {
4559 {
4562 "possible problem detected in invocation of "
4564 {
4567 "neither the destructor nor the class-specific "
4568 "operator delete will be called, even if they are "
4570 }
4571 }
4575 {
4576 tree dtor;
4579 {
4582 "deleting object of abstract class type %qT"
4583 " which has non-virtual destructor"
4585 else
4587 "deleting object of polymorphic class type %qT"
4588 " which has non-virtual destructor"
4590 }
4591 }
4592 }
4596 /* Throw away const and volatile on target type of addr. */
4598 }
4599 else
4600 {
4601 /* Don't check PROTECT here; leave that decision to the
4602 destructor. If the destructor is accessible, call it,
4603 else report error. */
4611 }
4614 {
4615 /* Make sure the destructor is callable. */
4617 {
4619 complain),
4623 }
4630 use_global_delete,
4633 complain);
4634 }
4635 else
4636 {
4639 tree ifexp;
4644 /* For `::delete x', we must not use the deleting destructor
4645 since then we would not be sure to get the global `operator
4646 delete'. */
4648 {
4649 /* We will use ADDR multiple times so we must save it. */
4652 /* Delete the object. */
4654 head,
4659 complain);
4660 /* Otherwise, treat this like a complete object destructor
4661 call. */
4663 }
4664 /* If the destructor is non-virtual, there is no deleting
4665 variant. Instead, we must explicitly call the appropriate
4666 `operator delete' here. */
4669 {
4670 /* We will use ADDR multiple times so we must save it. */
4672 /* Build the call. */
4674 addr,
4679 complain);
4680 /* Call the complete object destructor. */
4682 }
4685 {
4686 /* Make sure we have access to the member op delete, even though
4687 we'll actually be calling it from the destructor. */
4692 complain);
4693 }
4700 /* The delete operator must be called, regardless of whether
4701 the destructor throws.
4703 [expr.delete]/7 The deallocation function is called
4704 regardless of whether the destructor for the object or some
4705 element of the array throws an exception. */
4708 /* We need to calculate this before the dtor changes the vptr. */
4713 /* Explicit destructor call; don't check for null pointer. */
4715 else
4716 {
4717 /* Handle deleting a null pointer. */
4723 /* This is a compiler generated comparison, don't emit
4724 e.g. -Wnonnull-compare warning for it. */
4727 }
4733 }
4734 }
4736 /* At the beginning of a destructor, push cleanups that will call the
4737 destructors for our base classes and members.
4739 Called from begin_destructor_body. */
4741 void
4743 {
4746 tree member;
4747 tree expr;
4750 /* Run destructors for all virtual baseclasses. */
4753 {
4754 tree cond = (condition_conversion
4756 current_in_charge_parm,
4757 integer_two_node)));
4759 /* The CLASSTYPE_VBASECLASSES vector is in initialization
4760 order, which is also the right order for pushing cleanups. */
4763 {
4765 {
4767 base_dtor_identifier,
4768 NULL,
4769 base_binfo,
4770 (LOOKUP_NORMAL
4772 tf_warning_or_error);
4774 {
4778 }
4779 }
4780 }
4781 }
4783 /* Take care of the remaining baseclasses. */
4786 {
4792 base_dtor_identifier,
4795 tf_warning_or_error);
4798 }
4800 /* Don't automatically destroy union members. */
4806 {
4815 {
4816 tree this_member = (build_class_member_access_expr
4820 tf_warning_or_error));
4822 sfk_complete_destructor,
4827 }
4828 }
4829 }
4831 /* Build a C++ vector delete expression.
4832 MAXINDEX is the number of elements to be deleted.
4833 ELT_SIZE is the nominal size of each element in the vector.
4834 BASE is the expression that should yield the store to be deleted.
4835 This function expands (or synthesizes) these calls itself.
4836 AUTO_DELETE_VEC says whether the container (vector) should be deallocated.
4838 This also calls delete for virtual baseclasses of elements of the vector.
4840 Update: MAXINDEX is no longer needed. The size can be extracted from the
4841 start of the vector for pointers, and from the type for arrays. We still
4842 use MAXINDEX for arrays because it happens to already have one of the
4843 values we'd have to extract. (We could use MAXINDEX with pointers to
4844 confirm the size, and trap if the numbers differ; not clear that it'd
4845 be worth bothering.) */
4847 tree
4849 special_function_kind auto_delete_vec,
4851 {
4852 tree type;
4853 tree rval;
4859 {
4860 /* Step back one from start of vector, and read dimension. */
4861 tree cookie_addr;
4866 {
4869 }
4874 cookie_addr);
4876 }
4878 {
4879 /* Get the total number of things in the array, maxindex is a
4880 bad name. */
4887 {
4890 }
4891 }
4892 else
4893 {
4897 }
4905 }