| blob | 9f81eae81579732d97fab4551fcbd53923fdb6fe |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * U T I L S *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2014, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License along with GCC; see the file COPYING3. If not see *
19 * <http://www.gnu.org/licenses/>. *
20 * *
21 * GNAT was originally developed by the GNAT team at New York University. *
22 * Extensive contributions were provided by Ada Core Technologies Inc. *
23 * *
24 ****************************************************************************/
66 /* If nonzero, pretend we are allocating at global level. */
69 /* The default alignment of "double" floating-point types, i.e. floating
70 point types whose size is equal to 64 bits, or 0 if this alignment is
71 not specifically capped. */
74 /* The default alignment of "double" or larger scalar types, i.e. scalar
75 types whose size is greater or equal to 64 bits, or 0 if this alignment
76 is not specifically capped. */
79 /* True if floating-point arithmetics may use wider intermediate results. */
82 /* Tree nodes for the various types and decls we create. */
85 /* Functions to call for each of the possible raise reasons. */
88 /* Likewise, but with extra info for each of the possible raise reasons. */
91 /* Forward declarations for handlers of attributes. */
106 /* Fake handler for attributes we don't properly support, typically because
107 they'd require dragging a lot of the common-c front-end circuitry. */
110 /* Table of machine-independent internal attributes for Ada. We support
111 this minimal set of attributes to accommodate the needs of builtins. */
113 {
114 /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler,
115 affects_type_identity } */
145 /* ??? format and format_arg are heavy and not supported, which actually
146 prevents support for stdio builtins, which we however declare as part
147 of the common builtins.def contents. */
152 };
154 /* Associates a GNAT tree node to a GCC tree node. It is used in
155 `save_gnu_tree', `get_gnu_tree' and `present_gnu_tree'. See documentation
156 of `save_gnu_tree' for more info. */
159 #define GET_GNU_TREE(GNAT_ENTITY) \
160 associate_gnat_to_gnu[(GNAT_ENTITY) - First_Node_Id]
162 #define SET_GNU_TREE(GNAT_ENTITY,VAL) \
163 associate_gnat_to_gnu[(GNAT_ENTITY) - First_Node_Id] = (VAL)
165 #define PRESENT_GNU_TREE(GNAT_ENTITY) \
166 (associate_gnat_to_gnu[(GNAT_ENTITY) - First_Node_Id] != NULL_TREE)
168 /* Associates a GNAT entity to a GCC tree node used as a dummy, if any. */
171 #define GET_DUMMY_NODE(GNAT_ENTITY) \
172 dummy_node_table[(GNAT_ENTITY) - First_Node_Id]
174 #define SET_DUMMY_NODE(GNAT_ENTITY,VAL) \
175 dummy_node_table[(GNAT_ENTITY) - First_Node_Id] = (VAL)
177 #define PRESENT_DUMMY_NODE(GNAT_ENTITY) \
178 (dummy_node_table[(GNAT_ENTITY) - First_Node_Id] != NULL_TREE)
180 /* This variable keeps a table for types for each precision so that we only
181 allocate each of them once. Signed and unsigned types are kept separate.
183 Note that these types are only used when fold-const requests something
184 special. Perhaps we should NOT share these types; we'll see how it
185 goes later. */
188 /* Likewise for float types, but record these by mode. */
191 /* For each binding contour we allocate a binding_level structure to indicate
192 the binding depth. */
195 /* The binding level containing this one (the enclosing binding level). */
197 /* The BLOCK node for this level. */
198 tree block;
199 /* If nonzero, the setjmp buffer that needs to be updated for any
200 variable-sized definition within this context. */
201 tree jmpbuf_decl;
202 };
204 /* The binding level currently in effect. */
207 /* A chain of gnat_binding_level structures awaiting reuse. */
210 /* The context to be used for global declarations. */
213 /* An array of global declarations. */
216 /* An array of builtin function declarations. */
219 /* An array of global renaming pointers. */
222 /* A chain of unused BLOCK nodes. */
229 /* A hash table of padded types. It is modelled on the generic type
230 hash table in tree.c, which must thus be used as a reference. */
233 tree type;
234 };
238 htab_t pad_type_hash_table;
248 /* A linked list used as a queue to defer the initialization of the
249 DECL_CONTEXT attribute of ..._DECL nodes and of the TYPE_CONTEXT attribute
250 of ..._TYPE nodes. */
251 struct deferred_decl_context_node
252 {
257 context to. */
259 };
263 /* Defer the initialization of DECL's DECL_CONTEXT attribute, scheduling to
264 feed it with the elaboration of GNAT_SCOPE. */
268 /* Defer the initialization of TYPE's TYPE_CONTEXT attribute, scheduling to
269 feed it with the DECL_CONTEXT computed as part of N as soon as it is
270 computed. */
272 tree type);
273 \f
274 /* Initialize data structures of the utils.c module. */
276 void
278 {
279 /* Initialize the association of GNAT nodes to GCC trees. */
282 /* Initialize the association of GNAT nodes to GCC trees as dummies. */
285 /* Initialize the hash table of padded types. */
286 pad_type_hash_table
288 }
290 /* Destroy data structures of the utils.c module. */
292 void
294 {
295 /* Destroy the association of GNAT nodes to GCC trees. */
299 /* Destroy the association of GNAT nodes to GCC trees as dummies. */
303 /* Destroy the hash table of padded types. */
307 /* Invalidate the global renaming pointers. */
309 }
310 \f
311 /* GNAT_ENTITY is a GNAT tree node for an entity. Associate GNU_DECL, a GCC
312 tree node, with GNAT_ENTITY. If GNU_DECL is not a ..._DECL node, abort.
313 If NO_CHECK is true, the latter check is suppressed.
315 If GNU_DECL is zero, reset a previous association. */
317 void
319 {
320 /* Check that GNAT_ENTITY is not already defined and that it is being set
321 to something which is a decl. If that is not the case, this usually
322 means GNAT_ENTITY is defined twice, but occasionally is due to some
323 Gigi problem. */
329 }
331 /* GNAT_ENTITY is a GNAT tree node for an entity. Return the GCC tree node
332 that was associated with it. If there is no such tree node, abort.
334 In some cases, such as delayed elaboration or expressions that need to
335 be elaborated only once, GNAT_ENTITY is really not an entity. */
337 tree
339 {
342 }
344 /* Return nonzero if a GCC tree has been associated with GNAT_ENTITY. */
346 bool
348 {
350 }
351 \f
352 /* Make a dummy type corresponding to GNAT_TYPE. */
354 tree
356 {
358 tree gnu_type;
360 /* If there was no equivalent type (can only happen when just annotating
361 types) or underlying type, go back to the original type. */
365 /* If it there already a dummy type, use that one. Else make one. */
369 /* If this is a record, make a RECORD_TYPE or UNION_TYPE; else make
370 an ENUMERAL_TYPE. */
384 }
386 /* Return the dummy type that was made for GNAT_TYPE, if any. */
388 tree
390 {
392 }
394 /* Build dummy fat and thin pointer types whose designated type is specified
395 by GNAT_DESIG_TYPE/GNU_DESIG_TYPE and attach them to the latter. */
397 void
399 {
414 /* Build a stub DECL to trigger the special processing for fat pointer types
415 in gnat_pushdecl. */
418 gnu_fat_type);
426 /* Suppress debug info until after the type is completed. */
435 }
436 \f
437 /* Return true if we are in the global binding level. */
439 bool
441 {
443 }
445 /* Enter a new binding level. */
447 void
449 {
452 /* Reuse a struct for this binding level, if there is one. */
454 {
457 }
458 else
461 /* Use a free BLOCK, if any; otherwise, allocate one. */
463 {
467 }
468 else
471 /* Point the BLOCK we just made to its parent. */
479 /* Add this level to the front of the chain (stack) of active levels. */
483 }
485 /* Set SUPERCONTEXT of the BLOCK for the current binding level to FNDECL
486 and point FNDECL to this BLOCK. */
488 void
490 {
494 }
496 /* Set the jmpbuf_decl for the current binding level to DECL. */
498 void
500 {
502 }
504 /* Get the jmpbuf_decl, if any, for the current binding level. */
506 tree
508 {
510 }
512 /* Exit a binding level. Set any BLOCK into the current code group. */
514 void
516 {
523 /* If this is a function-level BLOCK don't do anything. Otherwise, if there
524 are no variables free the block and merge its subblocks into those of its
525 parent block. Otherwise, add it to the list of its parent. */
527 ;
529 {
535 }
536 else
537 {
542 }
544 /* Free this binding structure. */
548 }
550 /* Exit a binding level and discard the associated BLOCK. */
552 void
554 {
561 /* Free this binding structure. */
565 }
566 \f
567 /* Set the context of TYPE and its parallel types (if any) to CONTEXT. */
569 static void
571 {
577 {
580 /* Give a context to the parallel types and their stub decl, if any.
581 Some parallel types seems to be present in multiple parallel type
582 chains, so don't mess with their context if they already have one. */
584 {
588 }
591 }
592 }
594 /* Return the innermost scope, starting at GNAT_NODE, we are be interested in
595 the debug info, or Empty if there is no such scope. If not NULL, set
596 IS_SUBPROGRAM to whether the returned entity is a subprogram. */
598 static Entity_Id
600 {
601 Entity_Id gnat_entity;
608 else
612 {
614 {
620 /* If the scope is a subprogram, then just rely on
621 current_function_decl, so that we don't have to defer
622 anything. This is needed because other places rely on the
623 validity of the DECL_CONTEXT attribute of FUNCTION_DECL nodes. */
633 /* By default, we are not interested in this particular scope: go to
634 the outer one. */
636 }
638 }
640 }
642 /* If N is NULL, set TYPE's context to CONTEXT. Defer this to the processing of
643 N otherwise. */
645 static void
647 tree context,
649 {
652 else
654 }
656 /* Return global_context. Create it if needed, first. */
658 static tree
660 {
664 }
666 /* Record DECL as belonging to the current lexical scope and use GNAT_NODE
667 for location information and flag propagation. */
669 void
671 {
675 /* If explicitely asked to make DECL global or if it's an imported nested
676 object, short-circuit the regular Scope-based context computation. */
678 {
679 /* Rely on the GNAT scope, or fallback to the current_function_decl if
680 the GNAT scope reached the global scope, if it reached a subprogram
681 or the declaration is a subprogram or a variable (for them we skip
682 intermediate context types because the subprogram body elaboration
683 machinery and the inliner both expect a subprogram context).
685 Falling back to current_function_decl is necessary for implicit
686 subprograms created by gigi, such as the elaboration subprograms. */
688 const Entity_Id gnat_scope
692 && !context_is_subprogram
695 /* Always assume the scope has not been elaborated, thus defer the
696 context propagation to the time its elaboration will be
697 available. */
698 deferred_decl_context
701 /* External declarations (when force_global > 0) may not be in a
702 local context. */
705 }
707 /* If either we are forced to be in global mode or if both the GNAT scope and
708 the current_function_decl did not help determining the context, use the
709 global scope. */
713 /* Functions imported in another function are not really nested.
714 For really nested functions mark them initially as needing
715 a static chain for uses of that flag before unnesting;
716 lower_nested_functions will then recompute it. */
729 /* Set the location of DECL and emit a declaration for it. */
735 /* Put the declaration on the list. The list of declarations is in reverse
736 order. The list will be reversed later. Put global declarations in the
737 globals list and local ones in the current block. But skip TYPE_DECLs
738 for UNCONSTRAINED_ARRAY_TYPE in both cases, as they will cause trouble
739 with the debugger and aren't needed anyway. */
742 {
744 {
747 }
750 else
751 {
754 }
755 }
757 /* For the declaration of a type, set its name if it either is not already
758 set or if the previous type name was not derived from a source name.
759 We'd rather have the type named with a real name and all the pointer
760 types to the same object have the same POINTER_TYPE node. Code in the
761 equivalent function of c-decl.c makes a copy of the type node here, but
762 that may cause us trouble with incomplete types. We make an exception
763 for fat pointer types because the compiler automatically builds them
764 for unconstrained array types and the debugger uses them to represent
765 both these and pointers to these. */
767 {
771 {
772 /* Array and pointer types aren't "tagged" types so we force the
773 type to be associated with its typedef in the DWARF back-end,
774 in order to make sure that the latter is always preserved. */
778 {
785 deferred_decl_context);
788 }
789 }
791 {
792 /* We need a variant for the placeholder machinery to work. */
797 deferred_decl_context);
802 else
806 }
808 ;
809 else
812 /* Propagate the name to all the anonymous variants. This is needed
813 for the type qualifiers machinery to work properly. Also propagate
814 the context to them. Note that the context will be propagated to all
815 parallel types too thanks to gnat_set_type_context. */
819 {
823 deferred_decl_context);
824 }
825 }
826 }
827 \f
828 /* Create a record type that contains a SIZE bytes long field of TYPE with a
829 starting bit position so that it is aligned to ALIGN bits, and leaving at
830 least ROOM bytes free before the field. BASE_ALIGN is the alignment the
831 record is guaranteed to get. GNAT_NODE is used for the position of the
832 associated TYPE_DECL. */
834 tree
837 {
838 /* We will be crafting a record type with one field at a position set to be
839 the next multiple of ALIGN past record'address + room bytes. We use a
840 record placeholder to express record'address. */
844 tree record_addr_st
847 /* The diagram below summarizes the shape of what we manipulate:
849 <--------- pos ---------->
850 { +------------+-------------+-----------------+
851 record =>{ |############| ... | field (type) |
852 { +------------+-------------+-----------------+
853 |<-- room -->|<- voffset ->|<---- size ----->|
854 o o
855 | |
856 record_addr vblock_addr
858 Every length is in sizetype bytes there, except "pos" which has to be
859 set as a bit position in the GCC tree for the record. */
869 /* Compute VOFFSET and then POS. The next byte position multiple of some
870 alignment after some address is obtained by "and"ing the alignment minus
871 1 with the two's complement of the address. */
876 /* POS = (ROOM + VOFFSET) * BIT_PER_UNIT, in bitsizetype. */
880 bitsize_unit_node);
882 /* Craft the GCC record representation. We exceptionally do everything
883 manually here because 1) our generic circuitry is not quite ready to
884 handle the complex position/size expressions we are setting up, 2) we
885 have a strong simplifying factor at hand: we know the maximum possible
886 value of voffset, and 3) we have to set/reset at least the sizes in
887 accordance with this maximum value anyway, as we need them to convey
888 what should be "alloc"ated for this type.
890 Use -1 as the 'addressable' indication for the field to prevent the
891 creation of a bitfield. We don't need one, it would have damaging
892 consequences on the alignment computation, and create_field_decl would
893 make one without this special argument, for instance because of the
894 complex position expression. */
905 bitsize_unit_node),
914 /* Declare it now since it will never be declared otherwise. This is
915 necessary to ensure that its subtrees are properly marked. */
919 }
921 /* TYPE is a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE that is being used
922 as the field type of a packed record if IN_RECORD is true, or as the
923 component type of a packed array if IN_RECORD is false. See if we can
924 rewrite it either as a type that has a non-BLKmode, which we can pack
925 tighter in the packed record case, or as a smaller type. If so, return
926 the new type. If not, return the original type. */
928 tree
930 {
936 /* No point in doing anything if the size is zero. */
942 /* Copy the name and flags from the old type to that of the new.
943 Note that we rely on the pointer equality created here for
944 TYPE_NAME to look through conversions in various places. */
951 /* If we are in a record and have a small size, set the alignment to
952 try for an integral mode. Otherwise set it to try for a smaller
953 type with BLKmode. */
955 {
959 }
960 else
961 {
964 /* Do not try to shrink the size if the RM size is not constant. */
969 /* Round the RM size up to a unit boundary to get the minimal size
970 for a BLKmode record. Give up if it's already the size. */
978 }
982 /* Now copy the fields, keeping the position and size as we don't want
983 to change the layout by propagating the packedness downwards. */
986 {
995 /* However, for the last field in a not already packed record type
996 that is of an aggregate type, we need to use the RM size in the
997 packable version of the record type, see finish_record_type. */
1005 else
1008 new_field
1021 }
1029 /* If this is a padding record, we never want to make the size smaller
1030 than what was specified. For QUAL_UNION_TYPE, also copy the size. */
1032 {
1036 }
1037 else
1038 {
1042 }
1049 /* Try harder to get a packable type if necessary, for example
1050 in case the record itself contains a BLKmode field. */
1055 /* If neither the mode nor the size has shrunk, return the old type. */
1060 }
1062 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
1063 If TYPE is the best type, return it. Otherwise, make a new type. We
1064 only support new integral and pointer types. FOR_BIASED is true if
1065 we are making a biased type. */
1067 tree
1069 {
1072 tree new_type;
1074 /* If size indicates an error, just return TYPE to avoid propagating
1075 the error. Likewise if it's too large to represent. */
1082 {
1089 /* Integer types with precision 0 are forbidden. */
1093 /* Only do something if the type isn't a packed array type and doesn't
1094 already have the proper size and the size isn't too large. */
1103 else
1108 /* Copy the name to show that it's essentially the same type and
1109 not a subrange type. */
1116 /* Do something if this is a fat pointer, in which case we
1117 may need to return the thin pointer. */
1119 {
1123 return
1124 build_pointer_type_for_mode
1127 }
1131 /* Only do something if this is a thin pointer, in which case we
1132 may need to return the fat pointer. */
1134 return
1140 }
1143 }
1145 /* See if the data pointed to by the hash table slot is marked. */
1147 static int
1149 {
1153 }
1155 /* Return the cached hash value. */
1157 static hashval_t
1159 {
1161 }
1163 /* Return 1 iff the padded types are equivalent. */
1165 static int
1167 {
1178 /* We consider that the padded types are equivalent if they pad the same
1179 type and have the same size, alignment and RM size. Taking the mode
1180 into account is redundant since it is determined by the others. */
1181 return
1186 }
1188 /* Look up the padded TYPE in the hash table and return its canonical version
1189 if it exists; otherwise, insert it into the hash table. */
1191 static tree
1193 {
1194 hashval_t hashcode;
1198 hashcode
1217 }
1219 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
1220 if needed. We have already verified that SIZE and ALIGN are large enough.
1221 GNAT_ENTITY is used to name the resulting record and to issue a warning.
1222 IS_COMPONENT_TYPE is true if this is being done for the component type of
1223 an array. IS_USER_TYPE is true if the original type needs to be completed.
1224 DEFINITION is true if this type is being defined. SET_RM_SIZE is true if
1225 the RM size of the resulting type is to be set to SIZE too. */
1227 tree
1231 {
1236 /* If TYPE is a padded type, see if it agrees with any size and alignment
1237 we were given. If so, return the original type. Otherwise, strip
1238 off the padding, since we will either be returning the inner type
1239 or repadding it. If no size or alignment is specified, use that of
1240 the original padded type. */
1242 {
1256 }
1258 /* If the size is either not being changed or is being made smaller (which
1259 is not done here and is only valid for bitfields anyway), show the size
1260 isn't changing. Likewise, clear the alignment if it isn't being
1261 changed. Then return if we aren't doing anything. */
1274 /* If requested, complete the original type and give it a name. */
1281 gnat_entity);
1283 /* We used to modify the record in place in some cases, but that could
1284 generate incorrect debugging information. So make a new record
1285 type and name. */
1297 bitsize_unit_node));
1299 /* If we are changing the alignment and the input type is a record with
1300 BLKmode and a small constant size, try to make a form that has an
1301 integral mode. This might allow the padding record to also have an
1302 integral mode, which will be much more efficient. There is no point
1303 in doing so if a size is specified unless it is also a small constant
1304 size and it is incorrect to do so if we cannot guarantee that the mode
1305 will be naturally aligned since the field must always be addressable.
1307 ??? This might not always be a win when done for a stand-alone object:
1308 since the nominal and the effective type of the object will now have
1309 different modes, a VIEW_CONVERT_EXPR will be required for converting
1310 between them and it might be hard to overcome afterwards, including
1311 at the RTL level when the stand-alone object is accessed as a whole. */
1319 && (!size
1322 {
1327 }
1329 /* Now create the field with the original size. */
1334 /* Do not emit debug info until after the auxiliary record is built. */
1337 /* Set the RM size if requested. */
1339 {
1340 tree canonical_pad_type;
1344 /* If the padded type is complete and has constant size, we canonicalize
1345 it by means of the hash table. This is consistent with the language
1346 semantics and ensures that gigi and the middle-end have a common view
1347 of these padded types. */
1350 {
1353 }
1354 }
1356 /* Unless debugging information isn't being written for the input type,
1357 write a record that shows what we are a subtype of and also make a
1358 variable that indicates our size, if still variable. */
1364 {
1384 }
1388 built:
1389 /* If the size was widened explicitly, maybe give a warning. Take the
1390 original size as the maximum size of the input if there was an
1391 unconstrained record involved and round it up to the specified alignment,
1392 if one was specified. But don't do it if we are just annotating types
1393 and the type is tagged, since tagged types aren't fully laid out in this
1394 mode. */
1414 {
1417 /* For a packed array, post the message on the original array type. */
1428 /* Generate message only for entities that come from source, since
1429 if we have an entity created by expansion, the message will be
1430 generated for some other corresponding source entity. */
1432 {
1441 }
1442 }
1445 }
1446 \f
1447 /* Relate the alias sets of GNU_NEW_TYPE and GNU_OLD_TYPE according to OP.
1448 If this is a multi-dimensional array type, do this recursively.
1450 OP may be
1451 - ALIAS_SET_COPY: the new set is made a copy of the old one.
1452 - ALIAS_SET_SUPERSET: the new set is made a superset of the old one.
1453 - ALIAS_SET_SUBSET: the new set is made a subset of the old one. */
1455 void
1457 {
1458 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
1459 of a one-dimensional array, since the padding has the same alias set
1460 as the field type, but if it's a multi-dimensional array, we need to
1461 see the inner types. */
1467 /* Unconstrained array types are deemed incomplete and would thus be given
1468 alias set 0. Retrieve the underlying array type. */
1470 gnu_old_type
1473 gnu_new_type
1482 {
1484 /* The alias set shouldn't be copied between array types with different
1485 aliasing settings because this can break the aliasing relationship
1486 between the array type and its element type. */
1487 #ifndef ENABLE_CHECKING
1489 #endif
1500 {
1504 /* Do nothing if the alias sets conflict. This ensures that we
1505 never call record_alias_subset several times for the same pair
1506 or at all for alias set 0. */
1508 {
1511 else
1513 }
1514 }
1519 }
1522 }
1523 \f
1524 /* Record TYPE as a builtin type for Ada. NAME is the name of the type.
1525 ARTIFICIAL_P is true if it's a type that was generated by the compiler. */
1527 void
1529 {
1538 }
1539 \f
1540 /* Given a record type RECORD_TYPE and a list of FIELD_DECL nodes FIELD_LIST,
1541 finish constructing the record type as a fat pointer type. */
1543 void
1545 {
1546 /* Make sure we can put it into a register. */
1550 /* Show what it really is. */
1553 /* Do not emit debug info for it since the types of its fields may still be
1554 incomplete at this point. */
1557 /* Force type_contains_placeholder_p to return true on it. Although the
1558 PLACEHOLDER_EXPRs are referenced only indirectly, this isn't a pointer
1559 type but the representation of the unconstrained array. */
1561 }
1563 /* Given a record type RECORD_TYPE and a list of FIELD_DECL nodes FIELD_LIST,
1564 finish constructing the record or union type. If REP_LEVEL is zero, this
1565 record has no representation clause and so will be entirely laid out here.
1566 If REP_LEVEL is one, this record has a representation clause and has been
1567 laid out already; only set the sizes and alignment. If REP_LEVEL is two,
1568 this record is derived from a parent record and thus inherits its layout;
1569 only make a pass on the fields to finalize them. DEBUG_INFO_P is true if
1570 we need to write debug information about this type. */
1572 void
1575 {
1583 tree field;
1587 /* Always attach the TYPE_STUB_DECL for a record type. It is required to
1588 generate debug info and have a parallel type. */
1591 /* Globally initialize the record first. If this is a rep'ed record,
1592 that just means some initializations; otherwise, layout the record. */
1594 {
1603 /* For all-repped records with a size specified, lay the QUAL_UNION_TYPE
1604 out just like a UNION_TYPE, since the size will be fixed. */
1607 }
1608 else
1609 {
1610 /* Ensure there isn't a size already set. There can be in an error
1611 case where there is a rep clause but all fields have errors and
1612 no longer have a position. */
1615 /* Ensure we use the traditional GCC layout for bitfields when we need
1616 to pack the record type or have a representation clause. The other
1617 possible layout (Microsoft C compiler), if available, would prevent
1618 efficient packing in almost all cases. */
1619 #ifdef TARGET_MS_BITFIELD_LAYOUT
1624 ATTR_FLAG_TYPE_IN_PLACE);
1625 #endif
1628 }
1630 /* At this point, the position and size of each field is known. It was
1631 either set before entry by a rep clause, or by laying out the type above.
1633 We now run a pass over the fields (in reverse order for QUAL_UNION_TYPEs)
1634 to compute the Ada size; the GCC size and alignment (for rep'ed records
1635 that are not padding types); and the mode (for rep'ed records). We also
1636 clear the DECL_BIT_FIELD indication for the cases we know have not been
1637 handled yet, and adjust DECL_NONADDRESSABLE_P accordingly. */
1643 {
1647 tree this_ada_size;
1654 else
1657 /* Clear DECL_BIT_FIELD for the cases layout_decl does not handle. */
1660 {
1663 /* In the general case, type alignment is required. */
1665 {
1666 /* The enclosing record type must be sufficiently aligned.
1667 Otherwise, if no alignment was specified for it and it
1668 has been laid out already, bump its alignment to the
1669 desired one if this is compatible with its size. */
1671 {
1674 }
1678 {
1682 }
1683 }
1685 /* In the non-strict alignment case, only byte alignment is. */
1690 }
1692 /* If we still have DECL_BIT_FIELD set at this point, we know that the
1693 field is technically not addressable. Except that it can actually
1694 be addressed if it is BLKmode and happens to be properly aligned. */
1700 /* A type must be as aligned as its most aligned field that is not
1701 a bit-field. But this is already enforced by layout_type. */
1707 {
1714 ada_size
1722 /* Since we know here that all fields are sorted in order of
1723 increasing bit position, the size of the record is one
1724 higher than the ending bit of the last field processed
1725 unless we have a rep clause, since in that case we might
1726 have a field outside a QUAL_UNION_TYPE that has a higher ending
1727 position. So use a MAX in that case. Also, if this field is a
1728 QUAL_UNION_TYPE, we need to take into account the previous size in
1729 the case of empty variants. */
1730 ada_size
1733 size
1740 }
1741 }
1747 {
1748 /* If this is a padding record, we never want to make the size smaller
1749 than what was specified in it, if any. */
1753 /* Now set any of the values we've just computed that apply. */
1759 {
1760 tree size_unit = had_size_unit
1764 bitsize_unit_node));
1772 }
1773 }
1777 }
1779 /* Append PARALLEL_TYPE on the chain of parallel types of TYPE. If
1780 PARRALEL_TYPE has no context and its computation is not deferred yet, also
1781 propagate TYPE's context to PARALLEL_TYPE's or defer its propagation to the
1782 moment TYPE will get a context. */
1784 void
1786 {
1794 /* If PARALLEL_TYPE already has a context, we are done. */
1798 /* Otherwise, try to get one from TYPE's context. */
1800 /* TYPE already has a context, so simply propagate it to PARALLEL_TYPE. */
1803 /* ... otherwise TYPE has not context yet. We know it will thanks to
1804 gnat_pushdecl, and then its context will be propagated to PARALLEL_TYPE.
1805 So we have nothing to do in this case. */
1806 }
1808 /* Return true if TYPE has a parallel type. */
1810 static bool
1812 {
1816 }
1818 /* Wrap up compilation of RECORD_TYPE, i.e. output all the debug information
1819 associated with it. It need not be invoked directly in most cases since
1820 finish_record_type takes care of doing so, but this can be necessary if
1821 a parallel type is to be attached to the record type. */
1823 void
1825 {
1827 tree field;
1829 /* If this is a padded type, the bulk of the debug info has already been
1830 generated for the field's type. */
1834 /* If the type already has a parallel type (XVS type), then we're done. */
1839 {
1840 /* We need to make an XVE/XVU record if any field has variable size,
1841 whether or not the record does. For example, if we have a union,
1842 it may be that all fields, rounded up to the alignment, have the
1843 same size, in which case we'll use that size. But the debug
1844 output routines (except Dwarf2) won't be able to output the fields,
1845 so we need to make the special record. */
1847 /* If a field has a non-constant qualifier, the record will have
1848 variable size too. */
1851 {
1854 }
1855 }
1857 /* If this record type is of variable size, make a parallel record type that
1858 will tell the debugger how the former is laid out (see exp_dbug.ads). */
1860 {
1861 tree new_record_type
1868 new_name
1881 /* Now scan all the fields, replacing each field with a new field
1882 corresponding to the new encoding. */
1885 {
1893 /* We're going to do some pattern matching below so remove as many
1894 conversions as possible. */
1897 /* See how the position was modified from the last position.
1899 There are two basic cases we support: a value was added
1900 to the last position or the last position was rounded to
1901 a boundary and they something was added. Check for the
1902 first case first. If not, see if there is any evidence
1903 of rounding. If so, round the last position and retry.
1905 If this is a union, the position can be taken as zero. */
1908 else
1914 {
1920 }
1925 && tree_fits_uhwi_p
1927 {
1929 unsigned HOST_WIDE_INT addend
1931 align
1937 }
1939 {
1943 }
1945 /* If we can't compute a position, set it to zero.
1947 ??? We really should abort here, but it's too much work
1948 to get this correct for all cases. */
1952 /* See if this type is variable-sized and make a pointer type
1953 and indicate the indirection if so. Beware that the debug
1954 back-end may adjust the position computed above according
1955 to the alignment of the field type, i.e. the pointer type
1956 in this case, if we don't preventively counter that. */
1958 {
1961 {
1964 }
1966 }
1968 /* Make a new field name, if necessary. */
1970 {
1976 else
1980 }
1982 new_field
1988 /* If old_field is a QUAL_UNION_TYPE, take its size as being
1989 zero. The only time it's not the last field of the record
1990 is when there are other components at fixed positions after
1991 it (meaning there was a rep clause for every field) and we
1992 want to be able to encode them. */
1996 ? bitsize_zero_node
1999 }
2004 }
2005 }
2007 /* Utility function of above to merge LAST_SIZE, the previous size of a record
2008 with FIRST_BIT and SIZE that describe a field. SPECIAL is true if this
2009 represents a QUAL_UNION_TYPE in which case we must look for COND_EXPRs and
2010 replace a value of zero with the old size. If HAS_REP is true, we take the
2011 MAX of the end position of this field with LAST_SIZE. In all other cases,
2012 we use FIRST_BIT plus SIZE. Return an expression for the size. */
2014 static tree
2017 {
2019 tree new_size;
2022 {
2026 }
2028 else
2039 /* We don't need any NON_VALUE_EXPRs and they can confuse us (especially
2040 when fed through substitute_in_expr) into thinking that a constant
2041 size is not constant. */
2046 }
2048 /* Utility function of above to see if OP0 and OP1, both of SIZETYPE, are
2049 related by the addition of a constant. Return that constant if so. */
2051 static tree
2053 {
2063 else
2065 }
2067 /* Utility function of above to split a tree OP which may be a sum, into a
2068 constant part, which is returned, and a variable part, which is stored
2069 in *PVAR. *PVAR may be bitsize_zero_node. All operations must be of
2070 bitsizetype. */
2072 static tree
2074 {
2075 /* Strip conversions in order to ease the tree traversal and maximize the
2076 potential for constant or plus/minus discovery. We need to be careful
2077 to always return and set *pvar to bitsizetype trees, but it's worth
2078 the effort. */
2084 {
2087 }
2089 {
2100 }
2101 else
2103 }
2104 \f
2105 /* Return a FUNCTION_TYPE node. RETURN_TYPE is the type returned by the
2106 subprogram. If it is VOID_TYPE, then we are dealing with a procedure,
2107 otherwise we are dealing with a function. PARAM_DECL_LIST is a list of
2108 PARM_DECL nodes that are the subprogram parameters. CICO_LIST is the
2109 copy-in/copy-out list to be stored into the TYPE_CICO_LIST field.
2110 RETURN_UNCONSTRAINED_P is true if the function returns an unconstrained
2111 object. RETURN_BY_DIRECT_REF_P is true if the function returns by direct
2112 reference. RETURN_BY_INVISI_REF_P is true if the function returns by
2113 invisible reference. */
2115 tree
2119 {
2120 /* A list of the data type nodes of the subprogram formal parameters.
2121 This list is generated by traversing the input list of PARM_DECL
2122 nodes. */
2131 /* TYPE may have been shared since GCC hashes types. If it has a different
2132 CICO_LIST, make a copy. Likewise for the various flags. */
2135 {
2141 }
2144 }
2145 \f
2146 /* Return a copy of TYPE but safe to modify in any way. */
2148 tree
2150 {
2153 /* Unshare the language-specific data. */
2155 {
2158 }
2160 /* And the contents of the language-specific slot if needed. */
2163 {
2168 }
2170 /* copy_node clears this field instead of copying it, because it is
2171 aliased with TREE_CHAIN. */
2180 }
2181 \f
2182 /* Return a subtype of sizetype with range MIN to MAX and whose
2183 TYPE_INDEX_TYPE is INDEX. GNAT_NODE is used for the position
2184 of the associated TYPE_DECL. */
2186 tree
2188 {
2189 /* First build a type for the desired range. */
2192 /* Then set the index type. */
2197 }
2199 /* Return a subtype of TYPE with range MIN to MAX. If TYPE is NULL,
2200 sizetype is used. */
2202 tree
2204 {
2205 tree range_type;
2210 /* First build a type with the base range. */
2214 /* Then set the actual range. */
2219 }
2220 \f
2221 /* Return a TYPE_DECL node suitable for the TYPE_STUB_DECL field of a type.
2222 TYPE_NAME gives the name of the type and TYPE is a ..._TYPE node giving
2223 its data type. */
2225 tree
2227 {
2228 /* Using a named TYPE_DECL ensures that a type name marker is emitted in
2229 STABS while setting DECL_ARTIFICIAL ensures that no DW_TAG_typedef is
2230 emitted in DWARF. */
2235 }
2237 /* Return a TYPE_DECL node. TYPE_NAME gives the name of the type and TYPE
2238 is a ..._TYPE node giving its data type. ARTIFICIAL_P is true if this
2239 is a declaration that was generated by the compiler. DEBUG_INFO_P is
2240 true if we need to write debug information about this type. GNAT_NODE
2241 is used for the position of the decl. */
2243 tree
2246 {
2249 tree type_decl;
2251 /* Only the builtin TYPE_STUB_DECL should be used for dummy types. */
2254 /* If the type hasn't been named yet, we're naming it; preserve an existing
2255 TYPE_STUB_DECL that has been attached to it for some purpose. */
2257 {
2260 }
2261 else
2267 /* Add this decl to the current binding level. */
2270 /* If we're naming the type, equate the TYPE_STUB_DECL to the name.
2271 This causes the name to be also viewed as a "tag" by the debug
2272 back-end, with the advantage that no DW_TAG_typedef is emitted
2273 for artificial "tagged" types in DWARF. */
2277 /* Do not generate debug info for UNCONSTRAINED_ARRAY_TYPE that the
2278 back-end doesn't support, and for others if we don't need to. */
2283 }
2284 \f
2285 /* Return a VAR_DECL or CONST_DECL node.
2287 VAR_NAME gives the name of the variable. ASM_NAME is its assembler name
2288 (if provided). TYPE is its data type (a GCC ..._TYPE node). VAR_INIT is
2289 the GCC tree for an optional initial expression; NULL_TREE if none.
2291 CONST_FLAG is true if this variable is constant, in which case we might
2292 return a CONST_DECL node unless CONST_DECL_ALLOWED_P is false.
2294 PUBLIC_FLAG is true if this is for a reference to a public entity or for a
2295 definition to be made visible outside of the current compilation unit, for
2296 instance variable definitions in a package specification.
2298 EXTERN_FLAG is true when processing an external variable declaration (as
2299 opposed to a definition: no storage is to be allocated for the variable).
2301 STATIC_FLAG is only relevant when not at top level. In that case
2302 it indicates whether to always allocate storage to the variable.
2304 GNAT_NODE is used for the position of the decl. */
2306 tree
2311 {
2312 /* Whether the initializer is a constant initializer. At the global level
2313 or for an external object or an object to be allocated in static memory,
2314 we check that it is a valid constant expression for use in initializing
2315 a static variable; otherwise, we only check that it is constant. */
2316 bool init_const
2323 /* Whether we will make TREE_CONSTANT the DECL we produce here, in which
2324 case the initializer may be used in-lieu of the DECL node (as done in
2325 Identifier_to_gnu). This is useful to prevent the need of elaboration
2326 code when an identifier for which such a decl is made is in turn used as
2327 an initializer. We used to rely on CONST vs VAR_DECL for this purpose,
2328 but extra constraints apply to this choice (see below) and are not
2329 relevant to the distinction we wish to make. */
2332 /* The actual DECL node. CONST_DECL was initially intended for enumerals
2333 and may be used for scalars in general but not for aggregates. */
2334 tree var_decl
2340 /* If this is external, throw away any initializations (they will be done
2341 elsewhere) unless this is a constant for which we would like to remain
2342 able to get the initializer. If we are defining a global here, leave a
2343 constant initialization and save any variable elaborations for the
2344 elaboration routine. If we are just annotating types, throw away the
2345 initialization if it isn't a constant. */
2350 /* At the global level, an initializer requiring code to be generated
2351 produces elaboration statements. Check that such statements are allowed,
2352 that is, not violating a No_Elaboration_Code restriction. */
2364 /* Ada doesn't feature Fortran-like COMMON variables so we shouldn't
2365 try to fiddle with DECL_COMMON. However, on platforms that don't
2366 support global BSS sections, uninitialized global variables would
2367 go in DATA instead, thus increasing the size of the executable. */
2374 /* At the global binding level, we need to allocate static storage for the
2375 variable if it isn't external. Otherwise, we allocate automatic storage
2376 unless requested not to. */
2380 /* For an external constant whose initializer is not absolute, do not emit
2381 debug info. In DWARF this would mean a global relocation in a read-only
2382 section which runs afoul of the PE-COFF run-time relocation mechanism. */
2384 && constant_p
2385 && var_init
2393 /* ??? Some attributes cannot be applied to CONST_DECLs. */
2397 /* Add this decl to the current binding level. */
2401 {
2407 }
2410 }
2411 \f
2412 /* Return true if TYPE, an aggregate type, contains (or is) an array. */
2414 static bool
2416 {
2418 {
2422 {
2423 tree field;
2429 }
2436 }
2437 }
2439 /* Return a FIELD_DECL node. FIELD_NAME is the field's name, FIELD_TYPE is
2440 its type and RECORD_TYPE is the type of the enclosing record. If SIZE is
2441 nonzero, it is the specified size of the field. If POS is nonzero, it is
2442 the bit position. PACKED is 1 if the enclosing record is packed, -1 if it
2443 has Component_Alignment of Storage_Unit. If ADDRESSABLE is nonzero, it
2444 means we are allowed to take the address of the field; if it is negative,
2445 we should not make a bitfield, which is used by make_aligning_type. */
2447 tree
2450 {
2457 /* If FIELD_TYPE is BLKmode, we must ensure this is aligned to at least a
2458 byte boundary since GCC cannot handle less-aligned BLKmode bitfields.
2459 Likewise for an aggregate without specified position that contains an
2460 array, because in this case slices of variable length of this array
2461 must be handled by GCC and variable-sized objects need to be aligned
2462 to at least a byte boundary. */
2464 || (!pos
2469 /* If a size is specified, use it. Otherwise, if the record type is packed
2470 compute a size to use, which may differ from the object's natural size.
2471 We always set a size in this case to trigger the checks for bitfield
2472 creation below, which is typically required when no position has been
2473 specified. */
2477 {
2481 }
2483 /* If we may, according to ADDRESSABLE, make a bitfield if a size is
2484 specified for two reasons: first if the size differs from the natural
2485 size. Second, if the alignment is insufficient. There are a number of
2486 ways the latter can be true.
2488 We never make a bitfield if the type of the field has a nonconstant size,
2489 because no such entity requiring bitfield operations should reach here.
2491 We do *preventively* make a bitfield when there might be the need for it
2492 but we don't have all the necessary information to decide, as is the case
2493 of a field with no specified position in a packed record.
2495 We also don't look at STRICT_ALIGNMENT here, and rely on later processing
2496 in layout_decl or finish_record_type to clear the bit_field indication if
2497 it is in fact not needed. */
2499 && size
2504 || packed
2507 {
2511 {
2515 else
2517 }
2518 }
2522 /* Bump the alignment if need be, either for bitfield/packing purposes or
2523 to satisfy the type requirements if no such consideration applies. When
2524 we get the alignment from the type, indicate if this is from an explicit
2525 user request, which prevents stor-layout from lowering it later on. */
2526 {
2527 unsigned int bit_align
2534 {
2537 }
2538 }
2541 {
2542 /* We need to pass in the alignment the DECL is known to have.
2543 This is the lowest-order bit set in POS, but no more than
2544 the alignment of the record, if one is specified. Note
2545 that an alignment of 0 is taken as infinite. */
2550 else
2564 }
2566 /* In addition to what our caller says, claim the field is addressable if we
2567 know that its type is not suitable.
2569 The field may also be "technically" nonaddressable, meaning that even if
2570 we attempt to take the field's address we will actually get the address
2571 of a copy. This is the case for true bitfields, but the DECL_BIT_FIELD
2572 value we have at this point is not accurate enough, so we don't account
2573 for this here and let finish_record_type decide. */
2580 }
2581 \f
2582 /* Return a PARM_DECL node. PARAM_NAME is the name of the parameter and
2583 PARAM_TYPE is its type. READONLY is true if the parameter is readonly
2584 (either an In parameter or an address of a pass-by-ref parameter). */
2586 tree
2588 {
2592 /* Honor TARGET_PROMOTE_PROTOTYPES like the C compiler, as not doing so
2593 can lead to various ABI violations. */
2597 {
2598 /* We have to be careful about biased types here. Make a subtype
2599 of integer_type_node with the proper biasing. */
2602 {
2603 tree subtype
2610 }
2611 else
2613 }
2618 }
2619 \f
2620 /* Process the attributes in ATTR_LIST for NODE, which is either a DECL or
2621 a TYPE. If IN_PLACE is true, the tree pointed to by NODE should not be
2622 changed. GNAT_NODE is used for the position of error messages. */
2624 void
2626 Node_Id gnat_node)
2627 {
2632 {
2641 {
2644 }
2650 else
2657 {
2660 }
2661 else
2680 }
2683 }
2684 \f
2685 /* Record DECL as a global renaming pointer. */
2687 void
2689 {
2692 }
2694 /* Invalidate the global renaming pointers that are not constant, lest their
2695 renamed object contains SAVE_EXPRs tied to an elaboration routine. Note
2696 that we should not blindly invalidate everything here because of the need
2697 to propagate constant values through renaming. */
2699 void
2701 {
2703 tree iter;
2713 }
2715 /* Return true if VALUE is a known to be a multiple of FACTOR, which must be
2716 a power of 2. */
2718 bool
2720 {
2729 }
2731 /* Return whether GNAT_NODE is a defining identifier for a renaming that comes
2732 from the parameter association for the instantiation of a generic. We do
2733 not want to emit source location for them: the code generated for their
2734 initialization is likely to disturb debugging. */
2736 bool
2738 {
2745 /* Get the object declaration of the renamed object, if any and if the
2746 renamed object is a mere identifier. */
2756 return
2760 }
2762 /* Defer the initialization of DECL's DECL_CONTEXT attribute, scheduling to
2763 feed it with the elaboration of GNAT_SCOPE. */
2767 {
2770 new_node
2779 }
2781 /* Defer the initialization of TYPE's TYPE_CONTEXT attribute, scheduling to
2782 feed it with the DECL_CONTEXT computed as part of N as soon as it is
2783 computed. */
2785 static void
2787 {
2789 }
2791 /* Get the GENERIC node corresponding to GNAT_SCOPE, if available. Return
2792 NULL_TREE if it is not available. */
2794 static tree
2796 {
2797 tree context;
2801 else
2805 {
2808 /* Skip dummy types: only the final ones can appear in the context
2809 chain. */
2813 /* ..._TYPE nodes are more useful than TYPE_DECL nodes in the context
2814 chain. */
2815 else
2817 }
2820 }
2822 /* Try to process all deferred nodes in the queue. Keep in the queue the ones
2823 that cannot be processed yet, remove the other ones. If FORCE is true,
2824 force the processing for all nodes, use the global context when nodes don't
2825 have a GNU translation. */
2827 void
2829 {
2834 {
2837 Entity_Id gnat_scope;
2841 /* If FORCE, get the innermost elaborated scope. Otherwise, just try to
2842 get the first scope. */
2845 {
2850 }
2852 /* Imported declarations must not be in a local context (i.e. not inside
2853 a function). */
2855 {
2859 {
2864 }
2865 }
2867 /* If FORCE, we want to get rid of all nodes in the queue: in case there
2868 was no elaborated scope, use the global context. */
2873 {
2874 tree t;
2879 /* Propagate it to the TYPE_CONTEXT attributes of the requested
2880 ..._TYPE nodes. */
2882 {
2884 }
2886 }
2888 /* If this node has been successfuly processed, remove it from the
2889 queue. Then move to the next node. */
2891 {
2895 }
2896 else
2898 }
2899 }
2902 /* Return VALUE scaled by the biggest power-of-2 factor of EXPR. */
2904 static unsigned int
2906 {
2909 /* An expression which is a bitwise AND with a mask has a power-of-2 factor
2910 corresponding to the number of trailing zeros of the mask. */
2913 {
2918 {
2921 i++;
2922 }
2923 }
2926 }
2928 /* Given two consecutive field decls PREV_FIELD and CURR_FIELD, return true
2929 unless we can prove these 2 fields are laid out in such a way that no gap
2930 exist between the end of PREV_FIELD and the beginning of CURR_FIELD. OFFSET
2931 is the distance in bits between the end of PREV_FIELD and the starting
2932 position of CURR_FIELD. It is ignored if null. */
2934 static bool
2936 {
2937 /* If this is the first field of the record, there cannot be any gap */
2941 /* If the previous field is a union type, then return false: The only
2942 time when such a field is not the last field of the record is when
2943 there are other components at fixed positions after it (meaning there
2944 was a rep clause for every field), in which case we don't want the
2945 alignment constraint to override them. */
2949 /* If the distance between the end of prev_field and the beginning of
2950 curr_field is constant, then there is a gap if the value of this
2951 constant is not null. */
2955 /* If the size and position of the previous field are constant,
2956 then check the sum of this size and position. There will be a gap
2957 iff it is not multiple of the current field alignment. */
2964 /* If both the position and size of the previous field are multiples
2965 of the current field alignment, there cannot be any gap. */
2970 /* Fallback, return that there may be a potential gap */
2972 }
2974 /* Return a LABEL_DECL with LABEL_NAME. GNAT_NODE is used for the position
2975 of the decl. */
2977 tree
2979 {
2980 tree label_decl
2985 /* Add this decl to the current binding level. */
2989 }
2990 \f
2991 /* Return a FUNCTION_DECL node. SUBPROG_NAME is the name of the subprogram,
2992 ASM_NAME is its assembler name, SUBPROG_TYPE is its type (a FUNCTION_TYPE
2993 node), PARAM_DECL_LIST is the list of the subprogram arguments (a list of
2994 PARM_DECL nodes chained through the DECL_CHAIN field).
2996 INLINE_STATUS, PUBLIC_FLAG, EXTERN_FLAG, ARTIFICIAL_FLAG and ATTR_LIST are
2997 used to set the appropriate fields in the FUNCTION_DECL. GNAT_NODE is
2998 used for the position of the decl. */
3000 tree
3005 {
3007 subprog_type);
3012 /* If this is a non-inline function nested inside an inlined external
3013 function, we cannot honor both requests without cloning the nested
3014 function in the current unit since it is private to the other unit.
3015 We could inline the nested function as well but it's probably better
3016 to err on the side of too little inlining. */
3018 && !public_flag
3019 && current_function_decl
3028 {
3041 ATTR_FLAG_TYPE_IN_PLACE);
3043 /* ... fall through ... */
3052 }
3065 {
3068 /* The expand_main_function circuitry expects "main_identifier_node" to
3069 designate the DECL_NAME of the 'main' entry point, in turn expected
3070 to be declared as the "main" function literally by default. Ada
3071 program entry points are typically declared with a different name
3072 within the binder generated file, exported as 'main' to satisfy the
3073 system expectations. Force main_identifier_node in this case. */
3076 }
3080 /* Add this decl to the current binding level. */
3083 /* Output the assembler code and/or RTL for the declaration. */
3087 }
3088 \f
3089 /* Set up the framework for generating code for SUBPROG_DECL, a subprogram
3090 body. This routine needs to be invoked before processing the declarations
3091 appearing in the subprogram. */
3093 void
3095 {
3096 tree param_decl;
3100 /* This function is being defined. */
3105 /* Enter a new binding level and show that all the parameters belong to
3106 this function. */
3114 }
3116 /* Finish translating the current subprogram and set its BODY. */
3118 void
3120 {
3123 /* Attach the BLOCK for this level to the function and pop the level. */
3128 /* Mark the RESULT_DECL as being in this subprogram. */
3131 /* The body should be a BIND_EXPR whose BLOCK is the top-level one. */
3133 {
3136 }
3141 }
3143 /* Wrap up compilation of SUBPROG_DECL, a subprogram body. */
3145 void
3147 {
3148 /* We cannot track the location of errors past this point. */
3151 /* If we're only annotating types, don't actually compile this function. */
3155 /* Dump functions before gimplification. */
3160 else
3161 /* Register this function with cgraph just far enough to get it
3162 added to our parent's nested function list. */
3164 }
3166 tree
3168 {
3171 }
3173 /* Return an integer type with the number of bits of precision given by
3174 PRECISION. UNSIGNEDP is nonzero if the type is unsigned; otherwise
3175 it is a signed type. */
3177 tree
3179 {
3180 tree t;
3189 else
3196 {
3199 }
3202 }
3204 /* Likewise for floating-point types. */
3206 static tree
3208 {
3209 tree t;
3221 {
3224 }
3227 }
3229 /* Return a data type that has machine mode MODE. UNSIGNEDP selects
3230 an unsigned type; otherwise a signed type is returned. */
3232 tree
3234 {
3251 {
3256 }
3259 }
3261 /* Return the unsigned version of a TYPE_NODE, a scalar type. */
3263 tree
3265 {
3269 {
3272 }
3276 {
3279 }
3282 }
3284 /* Return the signed version of a TYPE_NODE, a scalar type. */
3286 tree
3288 {
3292 {
3295 }
3299 {
3302 }
3305 }
3307 /* Return 1 if the types T1 and T2 are compatible, i.e. if they can be
3308 transparently converted to each other. */
3310 int
3312 {
3315 /* This is the default criterion. */
3319 /* We only check structural equivalence here. */
3323 /* Vector types are also compatible if they have the same number of subparts
3324 and the same form of (scalar) element type. */
3331 /* Array types are also compatible if they are constrained and have the same
3332 domain(s) and the same component type. */
3347 }
3349 /* Return true if EXPR is a useless type conversion. */
3351 bool
3353 {
3361 }
3363 /* Return true if T, a FUNCTION_TYPE, has the specified list of flags. */
3365 bool
3368 {
3373 }
3374 \f
3375 /* EXP is an expression for the size of an object. If this size contains
3376 discriminant references, replace them with the maximum (if MAX_P) or
3377 minimum (if !MAX_P) possible value of the discriminant. */
3379 tree
3381 {
3386 {
3393 {
3407 }
3411 /* If this contains a PLACEHOLDER_EXPR, it is the thing we want to
3412 modify. Otherwise, we treat it like a variable. */
3414 {
3418 }
3434 {
3439 /* Special-case wanting the maximum value of a MIN_EXPR.
3440 In that case, if one side overflows, return the other. */
3442 {
3448 }
3450 /* Likewise, handle a MINUS_EXPR or PLUS_EXPR with the LHS
3451 overflowing and the RHS a variable. */
3459 }
3463 {
3487 }
3489 /* Other tree classes cannot happen. */
3492 }
3495 }
3496 \f
3497 /* Build a template of type TEMPLATE_TYPE from the array bounds of ARRAY_TYPE.
3498 EXPR is an expression that we can use to locate any PLACEHOLDER_EXPRs.
3499 Return a constructor for the template. */
3501 tree
3503 {
3506 tree field;
3518 /* First make the list for a CONSTRUCTOR for the template. Go down the
3519 field list of the template instead of the type chain because this
3520 array might be an Ada array of arrays and we can't tell where the
3521 nested arrays stop being the underlying object. */
3524 (bound_list
3528 {
3531 /* If we have a bound list, get the bounds from there. Likewise
3532 for an ARRAY_TYPE. Otherwise, if expr is a PARM_DECL with
3533 DECL_BY_COMPONENT_PTR_P, use the bounds of the field in the template.
3534 This will give us a maximum range. */
3542 else
3548 /* If either MIN or MAX involve a PLACEHOLDER_EXPR, we must
3549 substitute it from OBJECT. */
3555 }
3558 }
3559 \f
3560 /* Return true if TYPE is suitable for the element type of a vector. */
3562 static bool
3564 {
3579 }
3581 /* Return a vector type given the SIZE and the INNER_TYPE, or NULL_TREE if
3582 this is not possible. If ATTRIBUTE is non-zero, we are processing the
3583 attribute declaration and want to issue error messages on failure. */
3585 static tree
3587 {
3591 /* Silently punt on variable sizes. We can't make vector types for them,
3592 need to ignore them on front-end generated subtypes of unconstrained
3593 base types, and this attribute is for binding implementors, not end
3594 users, so we should never get there from legitimate explicit uses. */
3600 {
3605 }
3609 {
3613 }
3616 {
3620 }
3624 {
3628 }
3631 }
3633 /* Return a vector type whose representative array type is ARRAY_TYPE, or
3634 NULL_TREE if this is not possible. If ATTRIBUTE is non-zero, we are
3635 processing the attribute and want to issue error messages on failure. */
3637 static tree
3639 {
3642 attribute);
3648 }
3649 \f
3650 /* Build a type to be used to represent an aliased object whose nominal type
3651 is an unconstrained array. This consists of a RECORD_TYPE containing a
3652 field of TEMPLATE_TYPE and a field of OBJECT_TYPE, which is an ARRAY_TYPE.
3653 If ARRAY_TYPE is that of an unconstrained array, this is used to represent
3654 an arbitrary unconstrained object. Use NAME as the name of the record.
3655 DEBUG_INFO_P is true if we need to write debug information for the type. */
3657 tree
3660 {
3661 tree decl;
3663 tree template_field
3666 tree array_field
3675 /* Declare it now since it will never be declared otherwise. This is
3676 necessary to ensure that its subtrees are properly marked. */
3679 /* template_type will not be used elsewhere than here, so to keep the debug
3680 info clean and in order to avoid scoping issues, make decl its
3681 context. */
3685 }
3687 /* Same, taking a thin or fat pointer type instead of a template type. */
3689 tree
3692 {
3693 tree template_type;
3697 template_type
3702 return
3704 }
3705 \f
3706 /* Update anything previously pointing to OLD_TYPE to point to NEW_TYPE.
3707 In the normal case this is just two adjustments, but we have more to
3708 do if NEW_TYPE is an UNCONSTRAINED_ARRAY_TYPE. */
3710 void
3712 {
3715 tree t;
3717 /* If this is the main variant, process all the other variants first. */
3722 /* If no pointers and no references, we are done. */
3726 /* Merge the old type qualifiers in the new type.
3728 Each old variant has qualifiers for specific reasons, and the new
3729 designated type as well. Each set of qualifiers represents useful
3730 information grabbed at some point, and merging the two simply unifies
3731 these inputs into the final type description.
3733 Consider for instance a volatile type frozen after an access to constant
3734 type designating it; after the designated type's freeze, we get here with
3735 a volatile NEW_TYPE and a dummy OLD_TYPE with a readonly variant, created
3736 when the access type was processed. We will make a volatile and readonly
3737 designated type, because that's what it really is.
3739 We might also get here for a non-dummy OLD_TYPE variant with different
3740 qualifiers than those of NEW_TYPE, for instance in some cases of pointers
3741 to private record type elaboration (see the comments around the call to
3742 this routine in gnat_to_gnu_entity <E_Access_Type>). We have to merge
3743 the qualifiers in those cases too, to avoid accidentally discarding the
3744 initial set, and will often end up with OLD_TYPE == NEW_TYPE then. */
3745 new_type
3749 /* If old type and new type are identical, there is nothing to do. */
3753 /* Otherwise, first handle the simple case. */
3755 {
3758 /* If pointer or reference already points to new type, nothing to do.
3759 This can happen as update_pointer_to can be invoked multiple times
3760 on the same couple of types because of the type variants. */
3765 /* Chain PTR and its variants at the end. */
3768 {
3772 }
3773 else
3776 /* Now adjust them. */
3779 {
3783 }
3785 /* Chain REF and its variants at the end. */
3788 {
3792 }
3793 else
3796 /* Now adjust them. */
3803 }
3805 /* Now deal with the unconstrained array case. In this case the pointer
3806 is actually a record where both fields are pointers to dummy nodes.
3807 Turn them into pointers to the correct types using update_pointer_to.
3808 Likewise for the pointer to the object record (thin pointer). */
3809 else
3810 {
3815 /* If PTR already points to NEW_TYPE, nothing to do. This can happen
3816 since update_pointer_to can be invoked multiple times on the same
3817 couple of types because of the type variants. */
3821 update_pointer_to
3825 update_pointer_to
3833 }
3834 }
3835 \f
3836 /* Convert EXPR, a pointer to a constrained array, into a pointer to an
3837 unconstrained one. This involves making or finding a template. */
3839 static tree
3841 {
3845 tree template_addr;
3849 /* If EXPR is null, make a fat pointer that contains a null pointer to the
3850 array (compare_fat_pointers ensures that this is the full discriminant)
3851 and a valid pointer to the bounds. This latter property is necessary
3852 since the compiler can hoist the load of the bounds done through it. */
3854 {
3860 else
3861 {
3862 /* The template type can still be dummy at this point so we build an
3863 empty constructor. The middle-end will fill it in with zeros. */
3865 NULL);
3869 }
3875 /* Do not set TREE_CONSTANT so as to force T to static memory. */
3880 }
3882 /* If EXPR is a thin pointer, make template and data from the record. */
3884 {
3889 /* If we have a TYPE_UNCONSTRAINED_ARRAY attached to the RECORD_TYPE,
3890 the thin pointer value has been shifted so we shift it back to get
3891 the template address. */
3893 {
3894 template_addr
3897 byte_position
3899 template_addr
3901 template_addr);
3902 }
3904 /* Otherwise we explicitly take the address of the fields. */
3905 else
3906 {
3908 template_addr
3916 }
3917 }
3919 /* Otherwise, build the constructor for the template. */
3920 else
3921 template_addr
3924 expr));
3926 /* The final result is a constructor for the fat pointer.
3928 If EXPR is an argument of a foreign convention subprogram, the type it
3929 points to is directly the component type. In this case, the expression
3930 type may not match the corresponding FIELD_DECL type at this point, so we
3931 call "convert" here to fix that up if necessary. This type consistency is
3932 required, for instance because it ensures that possible later folding of
3933 COMPONENT_REFs against this constructor always yields something of the
3934 same type as the initial reference.
3936 Note that the call to "build_template" above is still fine because it
3937 will only refer to the provided TEMPLATE_TYPE in this case. */
3941 }
3942 \f
3943 /* Create an expression whose value is that of EXPR,
3944 converted to type TYPE. The TREE_TYPE of the value
3945 is always TYPE. This function implements all reasonable
3946 conversions; callers should filter out those that are
3947 not permitted by the language being compiled. */
3949 tree
3951 {
3956 /* If the expression is already of the right type, we are done. */
3960 /* If both input and output have padding and are of variable size, do this
3961 as an unchecked conversion. Likewise if one is a mere variant of the
3962 other, so we avoid a pointless unpad/repad sequence. */
3970 ;
3972 /* If the output type has padding, convert to the inner type and make a
3973 constructor to build the record, unless a variable size is involved. */
3975 {
3978 /* If we previously converted from another type and our type is
3979 of variable size, remove the conversion to avoid the need for
3980 variable-sized temporaries. Likewise for a conversion between
3981 original and packable version. */
3989 /* If we are just removing the padding from expr, convert the original
3990 object if we have variable size in order to avoid the need for some
3991 variable-sized temporaries. Likewise if the padding is a variant
3992 of the other, so we avoid a pointless unpad/repad sequence. */
4003 /* If the inner type is of self-referential size and the expression type
4004 is a record, do this as an unchecked conversion. But first pad the
4005 expression if possible to have the same size on both sides. */
4008 {
4012 expr);
4014 }
4016 /* If we are converting between array types with variable size, do the
4017 final conversion as an unchecked conversion, again to avoid the need
4018 for some variable-sized temporaries. If valid, this conversion is
4019 very likely purely technical and without real effects. */
4026 expr),
4033 }
4035 /* If the input type has padding, remove it and convert to the output type.
4036 The conditions ordering is arranged to ensure that the output type is not
4037 a padding type here, as it is not clear whether the conversion would
4038 always be correct if this was to happen. */
4040 {
4041 tree unpadded;
4043 /* If we have just converted to this padded type, just get the
4044 inner expression. */
4050 /* Otherwise, build an explicit component reference. */
4051 else
4052 unpadded
4056 }
4058 /* If the input is a biased type, adjust first. */
4065 /* If the input is a justified modular type, we need to extract the actual
4066 object before converting it to any other type with the exceptions of an
4067 unconstrained array or of a mere type variant. It is useful to avoid the
4068 extraction and conversion in the type variant case because it could end
4069 up replacing a VAR_DECL expr by a constructor and we might be about the
4070 take the address of the result. */
4077 /* If converting to a type that contains a template, convert to the data
4078 type and then build the template. */
4080 {
4085 /* If the source already has a template, get a reference to the
4086 associated array only, as we are going to rebuild a template
4087 for the target type anyway. */
4096 }
4098 /* There are some cases of expressions that we process specially. */
4100 {
4105 /* Just set its type here. For TRANSFORM_EXPR, we will do the actual
4106 conversion in gnat_expand_expr. NULL_EXPR does not represent
4107 and actual value, so no conversion is needed. */
4113 /* If we are converting a STRING_CST to another constrained array type,
4114 just make a new one in the proper type. */
4118 {
4122 }
4126 /* If we are converting a VECTOR_CST to a mere type variant, just make
4127 a new one in the proper type. */
4129 {
4133 }
4136 /* If we are converting a CONSTRUCTOR to a mere type variant, or to
4137 another padding type around the same type, just make a new one in
4138 the proper type. */
4145 {
4150 }
4152 /* Likewise for a conversion between original and packable version, or
4153 conversion between types of the same size and with the same list of
4154 fields, but we have to work harder to preserve type consistency. */
4160 {
4169 /* Whether we need to clear TREE_CONSTANT et al. on the output
4170 constructor when we convert in place. */
4174 {
4175 /* Skip the missing fields in the CONSTRUCTOR. */
4177 {
4180 }
4181 /* The field must be the same. */
4184 constructor_elt elt
4188 /* If packing has made this field a bitfield and the input
4189 value couldn't be emitted statically any more, we need to
4190 clear TREE_CONSTANT on our output. */
4200 }
4202 /* If we have been able to match and convert all the input fields
4203 to their output type, convert in place now. We'll fallback to a
4204 view conversion downstream otherwise. */
4206 {
4213 }
4214 }
4216 /* Likewise for a conversion between array type and vector type with a
4217 compatible representative array. */
4221 etype))
4222 {
4227 tree value;
4229 /* Build a VECTOR_CST from a *constant* array constructor. */
4231 {
4234 /* Iterate through elements and check if all constructor
4235 elements are *_CSTs. */
4238 {
4241 }
4246 }
4248 /* Otherwise, build a regular vector constructor. */
4251 {
4254 }
4259 }
4263 /* First retrieve the underlying array. */
4270 {
4271 /* GCC 4.x is very sensitive to type consistency overall, and view
4272 conversions thus are very frequent. Even though just "convert"ing
4273 the inner operand to the output type is fine in most cases, it
4274 might expose unexpected input/output type mismatches in special
4275 circumstances so we avoid such recursive calls when we can. */
4278 /* If we are converting back to the original type, we can just
4279 lift the input conversion. This is a common occurrence with
4280 switches back-and-forth amongst type variants. */
4284 /* Otherwise, if we're converting between two aggregate or vector
4285 types, we might be allowed to substitute the VIEW_CONVERT_EXPR
4286 target type in place or to just convert the inner expression. */
4289 {
4290 /* If we are converting between mere variants, we can just
4291 substitute the VIEW_CONVERT_EXPR in place. */
4295 /* Otherwise, we may just bypass the input view conversion unless
4296 one of the types is a fat pointer, which is handled by
4297 specialized code below which relies on exact type matching. */
4301 }
4304 }
4308 }
4310 /* Check for converting to a pointer to an unconstrained array. */
4314 /* If we are converting between two aggregate or vector types that are mere
4315 variants, just make a VIEW_CONVERT_EXPR. Likewise when we are converting
4316 to a vector type from its representative array type. */
4323 etype)))
4326 /* If we are converting between tagged types, try to upcast properly. */
4329 {
4337 }
4339 /* If we are converting from a smaller form of record type back to it, just
4340 make a VIEW_CONVERT_EXPR. But first pad the expression to have the same
4341 size on both sides. */
4344 {
4347 expr);
4349 }
4351 /* In all other cases of related types, make a NOP_EXPR. */
4356 {
4372 /* ... fall through ... */
4376 /* If we are converting an additive expression to an integer type
4377 with lower precision, be wary of the optimization that can be
4378 applied by convert_to_integer. There are 2 problematic cases:
4379 - if the first operand was originally of a biased type,
4380 because we could be recursively called to convert it
4381 to an intermediate type and thus rematerialize the
4382 additive operator endlessly,
4383 - if the expression contains a placeholder, because an
4384 intermediate conversion that changes the sign could
4385 be inserted and thus introduce an artificial overflow
4386 at compile time when the placeholder is substituted. */
4391 {
4398 }
4404 /* If converting between two thin pointers, adjust if needed to account
4405 for differing offsets from the base pointer, depending on whether
4406 there is a TYPE_UNCONSTRAINED_ARRAY attached to the record type. */
4408 {
4409 tree etype_pos
4413 tree type_pos
4425 }
4427 /* If converting fat pointer to normal or thin pointer, get the pointer
4428 to the array and then convert it. */
4430 expr
4440 {
4446 expr));
4448 }
4450 /* ... fall through ... */
4453 /* In these cases, assume the front-end has validated the conversion.
4454 If the conversion is valid, it will be a bit-wise conversion, so
4455 it can be viewed as an unchecked conversion. */
4459 /* This is a either a conversion between a tagged type and some
4460 subtype, which we have to mark as a UNION_TYPE because of
4461 overlapping fields or a conversion of an Unchecked_Union. */
4465 /* If the input is a VECTOR_TYPE, convert to the representative
4466 array type first. */
4468 {
4472 }
4474 /* If EXPR is a constrained array, take its address, convert it to a
4475 fat pointer, and then dereference it. Likewise if EXPR is a
4476 record containing both a template and a constrained array.
4477 Note that a record representing a justified modular type
4478 always represents a packed constrained array. */
4483 return
4484 build_unary_op
4490 /* Do something very similar for converting one unconstrained
4491 array to another. */
4493 return
4498 else
4506 }
4507 }
4509 /* Create an expression whose value is that of EXPR converted to the common
4510 index type, which is sizetype. EXPR is supposed to be in the base type
4511 of the GNAT index type. Calling it is equivalent to doing
4513 convert (sizetype, expr)
4515 but we try to distribute the type conversion with the knowledge that EXPR
4516 cannot overflow in its type. This is a best-effort approach and we fall
4517 back to the above expression as soon as difficulties are encountered.
4519 This is necessary to overcome issues that arise when the GNAT base index
4520 type and the GCC common index type (sizetype) don't have the same size,
4521 which is quite frequent on 64-bit architectures. In this case, and if
4522 the GNAT base index type is signed but the iteration type of the loop has
4523 been forced to unsigned, the loop scalar evolution engine cannot compute
4524 a simple evolution for the general induction variables associated with the
4525 array indices, because it will preserve the wrap-around semantics in the
4526 unsigned type of their "inner" part. As a result, many loop optimizations
4527 are blocked.
4529 The solution is to use a special (basic) induction variable that is at
4530 least as large as sizetype, and to express the aforementioned general
4531 induction variables in terms of this induction variable, eliminating
4532 the problematic intermediate truncation to the GNAT base index type.
4533 This is possible as long as the original expression doesn't overflow
4534 and if the middle-end hasn't introduced artificial overflows in the
4535 course of the various simplification it can make to the expression. */
4537 tree
4539 {
4543 /* If the type is unsigned, overflow is allowed so we cannot be sure that
4544 EXPR doesn't overflow. Keep it simple if optimization is disabled. */
4549 {
4551 /* The main effect of the function: replace a loop parameter with its
4552 associated special induction variable. */
4557 CASE_CONVERT:
4558 {
4560 /* Bail out as soon as we suspect some sort of type frobbing. */
4564 }
4566 /* ... fall through ... */
4590 }
4593 }
4594 \f
4595 /* Remove all conversions that are done in EXP. This includes converting
4596 from a padded type or to a justified modular type. If TRUE_ADDRESS
4597 is true, always return the address of the containing object even if
4598 the address is not bit-aligned. */
4600 tree
4602 {
4604 {
4609 return
4618 CASE_CONVERT:
4625 }
4628 }
4629 \f
4630 /* If EXP's type is an UNCONSTRAINED_ARRAY_TYPE, return an expression that
4631 refers to the underlying array. If it has TYPE_CONTAINS_TEMPLATE_P,
4632 likewise return an expression pointing to the underlying array. */
4634 tree
4636 {
4641 {
4644 {
4652 {
4653 tree op1
4656 NULL_TREE,
4659 tree op2
4662 NULL_TREE,
4669 }
4670 else
4671 {
4678 }
4679 }
4688 /* If this is a padded type and it contains a template, convert to the
4689 unpadded type first. */
4693 {
4696 }
4699 {
4705 /* If the array type is padded, convert to the unpadded type. */
4708 }
4713 }
4716 }
4717 \f
4718 /* Return true if EXPR is an expression that can be folded as an operand
4719 of a VIEW_CONVERT_EXPR. See ada-tree.h for a complete rationale. */
4721 static bool
4723 {
4726 /* The folder will fold NOP_EXPRs between integral types with the same
4727 precision (in the middle-end's sense). We cannot allow it if the
4728 types don't have the same precision in the Ada sense as well. */
4735 /* Defer to the folder for non-integral conversions. */
4739 /* Only fold conversions that preserve both precisions. */
4745 }
4747 /* Return an expression that does an unchecked conversion of EXPR to TYPE.
4748 If NOTRUNC_P is true, truncation operations should be suppressed.
4750 Special care is required with (source or target) integral types whose
4751 precision is not equal to their size, to make sure we fetch or assign
4752 the value bits whose location might depend on the endianness, e.g.
4754 Rmsize : constant := 8;
4755 subtype Int is Integer range 0 .. 2 ** Rmsize - 1;
4757 type Bit_Array is array (1 .. Rmsize) of Boolean;
4758 pragma Pack (Bit_Array);
4760 function To_Bit_Array is new Unchecked_Conversion (Int, Bit_Array);
4762 Value : Int := 2#1000_0001#;
4763 Vbits : Bit_Array := To_Bit_Array (Value);
4765 we expect the 8 bits at Vbits'Address to always contain Value, while
4766 their original location depends on the endianness, at Value'Address
4767 on a little-endian architecture but not on a big-endian one. */
4769 tree
4771 {
4775 tree tem;
4778 /* If the expression is already of the right type, we are done. */
4782 /* If both types types are integral just do a normal conversion.
4783 Likewise for a conversion to an unconstrained array. */
4791 {
4793 {
4798 }
4801 {
4807 }
4808 else
4810 }
4812 /* If we are converting to an integral type whose precision is not equal
4813 to its size, first unchecked convert to a record type that contains an
4814 field of the given precision. Then extract the field. */
4819 {
4826 else
4838 }
4840 /* Similarly if we are converting from an integral type whose precision is
4841 not equal to its size, first copy into a field of the given precision
4842 and unchecked convert the record type. */
4847 {
4856 else
4869 }
4871 /* If we are converting from a scalar type to a type with a different size,
4872 we need to pad to have the same size on both sides.
4874 ??? We cannot do it unconditionally because unchecked conversions are
4875 used liberally by the front-end to implement polymorphism, e.g. in:
4877 S191s : constant ada__tags__addr_ptr := ada__tags__addr_ptr!(S190s);
4878 return p___size__4 (p__object!(S191s.all));
4880 so we skip all expressions that are references. */
4885 {
4887 {
4890 expr);
4892 }
4893 else
4894 {
4900 }
4901 }
4903 /* We have a special case when we are converting between two unconstrained
4904 array types. In that case, take the address, convert the fat pointer
4905 types, and dereference. */
4910 expr)));
4912 /* Another special case is when we are converting to a vector type from its
4913 representative array type; this a regular conversion. */
4917 etype))
4920 /* And, if the array type is not the representative, we try to build an
4921 intermediate vector type of which the array type is the representative
4922 and to do the unchecked conversion between the vector types, in order
4923 to enable further simplifications in the middle-end. */
4927 {
4930 }
4932 /* If we are converting a CONSTRUCTOR to a more aligned RECORD_TYPE, bump
4933 the alignment of the CONSTRUCTOR to speed up the copy operation. */
4937 {
4940 expr);
4942 }
4944 /* Otherwise, just build a VIEW_CONVERT_EXPR of the expression. */
4945 else
4946 {
4952 else
4954 }
4956 /* If the result is an integral type whose precision is not equal to its
4957 size, sign- or zero-extend the result. We need not do this if the input
4958 is an integral type of the same precision and signedness or if the output
4959 is a biased type or if both the input and output are unsigned. */
4972 {
4973 tree base_type
4975 tree shift_expr
4978 bitsize_int
4981 expr
4986 shift_expr),
4987 shift_expr));
4988 }
4990 /* An unchecked conversion should never raise Constraint_Error. The code
4991 below assumes that GCC's conversion routines overflow the same way that
4992 the underlying hardware does. This is probably true. In the rare case
4993 when it is false, we can rely on the fact that such conversions are
4994 erroneous anyway. */
4998 /* If the sizes of the types differ and this is an VIEW_CONVERT_EXPR,
4999 show no longer constant. */
5002 OEP_ONLY_CONST))
5006 }
5007 \f
5008 /* Return the appropriate GCC tree code for the specified GNAT_TYPE,
5009 the latter being a record type as predicated by Is_Record_Type. */
5011 enum tree_code
5013 {
5016 /* Return UNION_TYPE if it's an Unchecked_Union whose non-discriminant
5017 fields are all in the variant part. Otherwise, return RECORD_TYPE. */
5022 component_list
5032 }
5034 /* Return true if GNAT_TYPE is a "double" floating-point type, i.e. whose
5035 size is equal to 64 bits, or an array of such a type. Set ALIGN_CLAUSE
5036 according to the presence of an alignment clause on the type or, if it
5037 is an array, on the component type. */
5039 bool
5041 {
5047 {
5051 }
5060 }
5062 /* Return true if GNAT_TYPE is a "double" or larger scalar type, i.e. whose
5063 size is greater or equal to 64 bits, or an array of such a type. Set
5064 ALIGN_CLAUSE according to the presence of an alignment clause on the
5065 type or, if it is an array, on the component type. */
5067 bool
5069 {
5075 {
5079 }
5088 }
5090 /* Return true if GNU_TYPE is suitable as the type of a non-aliased
5091 component of an aggregate type. */
5093 bool
5095 {
5096 /* If the type is passed by reference, we may have pointers to the
5097 component so it cannot be made non-aliased. */
5101 /* We used to say that any component of aggregate type is aliased
5102 because the front-end may take 'Reference of it. The front-end
5103 has been enhanced in the meantime so as to use a renaming instead
5104 in most cases, but the back-end can probably take the address of
5105 such a component too so we go for the conservative stance.
5107 For instance, we might need the address of any array type, even
5108 if normally passed by copy, to construct a fat pointer if the
5109 component is used as an actual for an unconstrained formal.
5111 Likewise for record types: even if a specific record subtype is
5112 passed by copy, the parent type might be passed by ref (e.g. if
5113 it's of variable size) and we might take the address of a child
5114 component to pass to a parent formal. We have no way to check
5115 for such conditions here. */
5120 }
5122 /* Return true if TYPE is a smaller form of ORIG_TYPE. */
5124 bool
5126 {
5129 /* We're not interested in variants here. */
5133 /* Like a variant, a packable version keeps the original TYPE_NAME. */
5144 }
5146 /* Perform final processing on global variables. */
5150 void
5152 {
5154 tree iter;
5156 /* If we have declared types as used at the global level, insert them in
5157 the global hash table. We use a dummy variable for this purpose. */
5159 {
5164 dummy_global
5166 void_type_node);
5175 {
5178 }
5179 }
5181 /* Output debug information for all global type declarations first. This
5182 ensures that global types whose compilation hasn't been finalized yet,
5183 for example pointers to Taft amendment types, have their compilation
5184 finalized in the right context. */
5189 /* Proceed to optimize and emit assembly. */
5192 /* After cgraph has had a chance to emit everything that's going to
5193 be emitted, output debug information for the rest of globals. */
5195 {
5201 }
5202 }
5204 /* ************************************************************************
5205 * * GCC builtins support *
5206 * ************************************************************************ */
5208 /* The general scheme is fairly simple:
5210 For each builtin function/type to be declared, gnat_install_builtins calls
5211 internal facilities which eventually get to gnat_push_decl, which in turn
5212 tracks the so declared builtin function decls in the 'builtin_decls' global
5213 datastructure. When an Intrinsic subprogram declaration is processed, we
5214 search this global datastructure to retrieve the associated BUILT_IN DECL
5215 node. */
5217 /* Search the chain of currently available builtin declarations for a node
5218 corresponding to function NAME (an IDENTIFIER_NODE). Return the first node
5219 found, if any, or NULL_TREE otherwise. */
5220 tree
5222 {
5224 tree decl;
5231 }
5233 /* The code below eventually exposes gnat_install_builtins, which declares
5234 the builtin types and functions we might need, either internally or as
5235 user accessible facilities.
5237 ??? This is a first implementation shot, still in rough shape. It is
5238 heavily inspired from the "C" family implementation, with chunks copied
5239 verbatim from there.
5241 Two obvious TODO candidates are
5242 o Use a more efficient name/decl mapping scheme
5243 o Devise a middle-end infrastructure to avoid having to copy
5244 pieces between front-ends. */
5246 /* ----------------------------------------------------------------------- *
5247 * BUILTIN ELEMENTARY TYPES *
5248 * ----------------------------------------------------------------------- */
5250 /* Standard data types to be used in builtin argument declarations. */
5252 enum c_tree_index
5253 {
5255 CTI_STRING_TYPE,
5256 CTI_CONST_STRING_TYPE,
5258 CTI_MAX
5259 };
5263 #define signed_size_type_node c_global_trees[CTI_SIGNED_SIZE_TYPE]
5264 #define string_type_node c_global_trees[CTI_STRING_TYPE]
5265 #define const_string_type_node c_global_trees[CTI_CONST_STRING_TYPE]
5267 /* ??? In addition some attribute handlers, we currently don't support a
5268 (small) number of builtin-types, which in turns inhibits support for a
5269 number of builtin functions. */
5270 #define wint_type_node void_type_node
5271 #define intmax_type_node void_type_node
5272 #define uintmax_type_node void_type_node
5274 /* Build the void_list_node (void_type_node having been created). */
5276 static tree
5278 {
5281 }
5283 /* Used to help initialize the builtin-types.def table. When a type of
5284 the correct size doesn't exist, use error_mark_node instead of NULL.
5285 The later results in segfaults even when a decl using the type doesn't
5286 get invoked. */
5288 static tree
5290 {
5293 }
5295 /* Build/push the elementary type decls that builtin functions/types
5296 will need. */
5298 static void
5300 {
5306 const_string_type_node
5309 }
5311 /* ----------------------------------------------------------------------- *
5312 * BUILTIN FUNCTION TYPES *
5313 * ----------------------------------------------------------------------- */
5315 /* Now, builtin function types per se. */
5317 enum c_builtin_type
5318 {
5319 #define DEF_PRIMITIVE_TYPE(NAME, VALUE) NAME,
5320 #define DEF_FUNCTION_TYPE_0(NAME, RETURN) NAME,
5321 #define DEF_FUNCTION_TYPE_1(NAME, RETURN, ARG1) NAME,
5322 #define DEF_FUNCTION_TYPE_2(NAME, RETURN, ARG1, ARG2) NAME,
5323 #define DEF_FUNCTION_TYPE_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
5324 #define DEF_FUNCTION_TYPE_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
5325 #define DEF_FUNCTION_TYPE_5(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) NAME,
5326 #define DEF_FUNCTION_TYPE_6(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
5327 ARG6) NAME,
5328 #define DEF_FUNCTION_TYPE_7(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
5329 ARG6, ARG7) NAME,
5330 #define DEF_FUNCTION_TYPE_8(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
5331 ARG6, ARG7, ARG8) NAME,
5332 #define DEF_FUNCTION_TYPE_VAR_0(NAME, RETURN) NAME,
5333 #define DEF_FUNCTION_TYPE_VAR_1(NAME, RETURN, ARG1) NAME,
5334 #define DEF_FUNCTION_TYPE_VAR_2(NAME, RETURN, ARG1, ARG2) NAME,
5335 #define DEF_FUNCTION_TYPE_VAR_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
5336 #define DEF_FUNCTION_TYPE_VAR_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
5337 #define DEF_FUNCTION_TYPE_VAR_5(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
5338 NAME,
5339 #define DEF_POINTER_TYPE(NAME, TYPE) NAME,
5341 #undef DEF_PRIMITIVE_TYPE
5342 #undef DEF_FUNCTION_TYPE_0
5343 #undef DEF_FUNCTION_TYPE_1
5344 #undef DEF_FUNCTION_TYPE_2
5345 #undef DEF_FUNCTION_TYPE_3
5346 #undef DEF_FUNCTION_TYPE_4
5347 #undef DEF_FUNCTION_TYPE_5
5348 #undef DEF_FUNCTION_TYPE_6
5349 #undef DEF_FUNCTION_TYPE_7
5350 #undef DEF_FUNCTION_TYPE_8
5351 #undef DEF_FUNCTION_TYPE_VAR_0
5352 #undef DEF_FUNCTION_TYPE_VAR_1
5353 #undef DEF_FUNCTION_TYPE_VAR_2
5354 #undef DEF_FUNCTION_TYPE_VAR_3
5355 #undef DEF_FUNCTION_TYPE_VAR_4
5356 #undef DEF_FUNCTION_TYPE_VAR_5
5357 #undef DEF_POINTER_TYPE
5358 BT_LAST
5359 };
5363 /* A temporary array used in communication with def_fn_type. */
5366 /* A helper function for install_builtin_types. Build function type
5367 for DEF with return type RET and N arguments. If VAR is true, then the
5368 function should be variadic after those N arguments.
5370 Takes special care not to ICE if any of the types involved are
5371 error_mark_node, which indicates that said type is not in fact available
5372 (see builtin_type_for_size). In which case the function type as a whole
5373 should be error_mark_node. */
5375 static void
5377 {
5378 tree t;
5385 {
5391 }
5398 else
5401 egress:
5404 }
5406 /* Build the builtin function types and install them in the builtin_types
5407 array for later use in builtin function decls. */
5409 static void
5411 {
5412 tree va_list_ref_type_node;
5413 tree va_list_arg_type_node;
5416 {
5419 }
5420 else
5421 {
5424 }
5426 #define DEF_PRIMITIVE_TYPE(ENUM, VALUE) \
5427 builtin_types[ENUM] = VALUE;
5428 #define DEF_FUNCTION_TYPE_0(ENUM, RETURN) \
5429 def_fn_type (ENUM, RETURN, 0, 0);
5430 #define DEF_FUNCTION_TYPE_1(ENUM, RETURN, ARG1) \
5431 def_fn_type (ENUM, RETURN, 0, 1, ARG1);
5432 #define DEF_FUNCTION_TYPE_2(ENUM, RETURN, ARG1, ARG2) \
5433 def_fn_type (ENUM, RETURN, 0, 2, ARG1, ARG2);
5434 #define DEF_FUNCTION_TYPE_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
5435 def_fn_type (ENUM, RETURN, 0, 3, ARG1, ARG2, ARG3);
5436 #define DEF_FUNCTION_TYPE_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
5437 def_fn_type (ENUM, RETURN, 0, 4, ARG1, ARG2, ARG3, ARG4);
5438 #define DEF_FUNCTION_TYPE_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
5439 def_fn_type (ENUM, RETURN, 0, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
5440 #define DEF_FUNCTION_TYPE_6(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
5441 ARG6) \
5442 def_fn_type (ENUM, RETURN, 0, 6, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6);
5443 #define DEF_FUNCTION_TYPE_7(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
5444 ARG6, ARG7) \
5445 def_fn_type (ENUM, RETURN, 0, 7, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, ARG7);
5446 #define DEF_FUNCTION_TYPE_8(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
5447 ARG6, ARG7, ARG8) \
5448 def_fn_type (ENUM, RETURN, 0, 8, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, \
5449 ARG7, ARG8);
5450 #define DEF_FUNCTION_TYPE_VAR_0(ENUM, RETURN) \
5451 def_fn_type (ENUM, RETURN, 1, 0);
5452 #define DEF_FUNCTION_TYPE_VAR_1(ENUM, RETURN, ARG1) \
5453 def_fn_type (ENUM, RETURN, 1, 1, ARG1);
5454 #define DEF_FUNCTION_TYPE_VAR_2(ENUM, RETURN, ARG1, ARG2) \
5455 def_fn_type (ENUM, RETURN, 1, 2, ARG1, ARG2);
5456 #define DEF_FUNCTION_TYPE_VAR_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
5457 def_fn_type (ENUM, RETURN, 1, 3, ARG1, ARG2, ARG3);
5458 #define DEF_FUNCTION_TYPE_VAR_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
5459 def_fn_type (ENUM, RETURN, 1, 4, ARG1, ARG2, ARG3, ARG4);
5460 #define DEF_FUNCTION_TYPE_VAR_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
5461 def_fn_type (ENUM, RETURN, 1, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
5462 #define DEF_POINTER_TYPE(ENUM, TYPE) \
5463 builtin_types[(int) ENUM] = build_pointer_type (builtin_types[(int) TYPE]);
5467 #undef DEF_PRIMITIVE_TYPE
5468 #undef DEF_FUNCTION_TYPE_0
5469 #undef DEF_FUNCTION_TYPE_1
5470 #undef DEF_FUNCTION_TYPE_2
5471 #undef DEF_FUNCTION_TYPE_3
5472 #undef DEF_FUNCTION_TYPE_4
5473 #undef DEF_FUNCTION_TYPE_5
5474 #undef DEF_FUNCTION_TYPE_6
5475 #undef DEF_FUNCTION_TYPE_7
5476 #undef DEF_FUNCTION_TYPE_8
5477 #undef DEF_FUNCTION_TYPE_VAR_0
5478 #undef DEF_FUNCTION_TYPE_VAR_1
5479 #undef DEF_FUNCTION_TYPE_VAR_2
5480 #undef DEF_FUNCTION_TYPE_VAR_3
5481 #undef DEF_FUNCTION_TYPE_VAR_4
5482 #undef DEF_FUNCTION_TYPE_VAR_5
5483 #undef DEF_POINTER_TYPE
5485 }
5487 /* ----------------------------------------------------------------------- *
5488 * BUILTIN ATTRIBUTES *
5489 * ----------------------------------------------------------------------- */
5491 enum built_in_attribute
5492 {
5493 #define DEF_ATTR_NULL_TREE(ENUM) ENUM,
5494 #define DEF_ATTR_INT(ENUM, VALUE) ENUM,
5495 #define DEF_ATTR_STRING(ENUM, VALUE) ENUM,
5496 #define DEF_ATTR_IDENT(ENUM, STRING) ENUM,
5497 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) ENUM,
5499 #undef DEF_ATTR_NULL_TREE
5500 #undef DEF_ATTR_INT
5501 #undef DEF_ATTR_STRING
5502 #undef DEF_ATTR_IDENT
5503 #undef DEF_ATTR_TREE_LIST
5504 ATTR_LAST
5505 };
5509 static void
5511 {
5512 /* Fill in the built_in_attributes array. */
5513 #define DEF_ATTR_NULL_TREE(ENUM) \
5514 built_in_attributes[(int) ENUM] = NULL_TREE;
5515 #define DEF_ATTR_INT(ENUM, VALUE) \
5516 built_in_attributes[(int) ENUM] = build_int_cst (NULL_TREE, VALUE);
5517 #define DEF_ATTR_STRING(ENUM, VALUE) \
5518 built_in_attributes[(int) ENUM] = build_string (strlen (VALUE), VALUE);
5519 #define DEF_ATTR_IDENT(ENUM, STRING) \
5520 built_in_attributes[(int) ENUM] = get_identifier (STRING);
5521 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) \
5522 built_in_attributes[(int) ENUM] \
5523 = tree_cons (built_in_attributes[(int) PURPOSE], \
5524 built_in_attributes[(int) VALUE], \
5525 built_in_attributes[(int) CHAIN]);
5527 #undef DEF_ATTR_NULL_TREE
5528 #undef DEF_ATTR_INT
5529 #undef DEF_ATTR_STRING
5530 #undef DEF_ATTR_IDENT
5531 #undef DEF_ATTR_TREE_LIST
5532 }
5534 /* Handle a "const" attribute; arguments as in
5535 struct attribute_spec.handler. */
5537 static tree
5541 {
5544 else
5548 }
5550 /* Handle a "nothrow" attribute; arguments as in
5551 struct attribute_spec.handler. */
5553 static tree
5557 {
5560 else
5564 }
5566 /* Handle a "pure" attribute; arguments as in
5567 struct attribute_spec.handler. */
5569 static tree
5572 {
5575 /* ??? TODO: Support types. */
5576 else
5577 {
5581 }
5584 }
5586 /* Handle a "no vops" attribute; arguments as in
5587 struct attribute_spec.handler. */
5589 static tree
5593 {
5597 }
5599 /* Helper for nonnull attribute handling; fetch the operand number
5600 from the attribute argument list. */
5602 static bool
5604 {
5605 /* Verify the arg number is a constant. */
5611 }
5613 /* Handle the "nonnull" attribute. */
5614 static tree
5618 {
5622 /* If no arguments are specified, all pointer arguments should be
5623 non-null. Verify a full prototype is given so that the arguments
5624 will have the correct types when we actually check them later. */
5626 {
5628 {
5631 }
5633 }
5635 /* Argument list specified. Verify that each argument number references
5636 a pointer argument. */
5638 {
5642 {
5647 }
5650 {
5651 function_args_iterator iter;
5652 tree argument;
5656 {
5660 }
5664 {
5670 }
5673 {
5679 }
5680 }
5681 }
5684 }
5686 /* Handle a "sentinel" attribute. */
5688 static tree
5691 {
5693 {
5698 }
5699 else
5700 {
5702 {
5707 }
5708 }
5711 {
5715 {
5718 }
5719 else
5720 {
5722 {
5725 }
5726 }
5727 }
5730 }
5732 /* Handle a "noreturn" attribute; arguments as in
5733 struct attribute_spec.handler. */
5735 static tree
5738 {
5741 /* See FIXME comment in c_common_attribute_table. */
5747 = build_pointer_type
5750 else
5751 {
5755 }
5758 }
5760 /* Handle a "leaf" attribute; arguments as in
5761 struct attribute_spec.handler. */
5763 static tree
5766 {
5768 {
5771 }
5773 {
5776 }
5779 }
5781 /* Handle a "always_inline" attribute; arguments as in
5782 struct attribute_spec.handler. */
5784 static tree
5787 {
5789 {
5790 /* Set the attribute and mark it for disregarding inline limits. */
5792 }
5793 else
5794 {
5797 }
5800 }
5802 /* Handle a "malloc" attribute; arguments as in
5803 struct attribute_spec.handler. */
5805 static tree
5808 {
5812 else
5813 {
5817 }
5820 }
5822 /* Fake handler for attributes we don't properly support. */
5824 tree
5830 {
5832 }
5834 /* Handle a "type_generic" attribute. */
5836 static tree
5840 {
5841 /* Ensure we have a function type. */
5844 /* Ensure we have a variadic function. */
5848 }
5850 /* Handle a "vector_size" attribute; arguments as in
5851 struct attribute_spec.handler. */
5853 static tree
5856 {
5858 tree vector_type;
5862 /* We need to provide for vector pointers, vector arrays, and
5863 functions returning vectors. For example:
5865 __attribute__((vector_size(16))) short *foo;
5867 In this case, the mode is SI, but the type being modified is
5868 HI, so we need to look further. */
5878 /* Build back pointers if needed. */
5882 }
5884 /* Handle a "vector_type" attribute; arguments as in
5885 struct attribute_spec.handler. */
5887 static tree
5890 {
5892 tree vector_type;
5897 {
5901 }
5911 }
5913 /* ----------------------------------------------------------------------- *
5914 * BUILTIN FUNCTIONS *
5915 * ----------------------------------------------------------------------- */
5917 /* Worker for DEF_BUILTIN. Possibly define a builtin function with one or two
5918 names. Does not declare a non-__builtin_ function if flag_no_builtin, or
5919 if nonansi_p and flag_no_nonansi_builtin. */
5921 static void
5929 {
5930 tree decl;
5933 /* Preserve an already installed decl. It most likely was setup in advance
5934 (e.g. as part of the internal builtins) for specific reasons. */
5945 fnattrs);
5947 /* ??? This is normally further controlled by command-line options
5948 like -fno-builtin, but we don't have them for Ada. */
5953 }
5959 /* Install what the common builtins.def offers. */
5961 static void
5963 {
5964 #define DEF_BUILTIN(ENUM, NAME, CLASS, TYPE, LIBTYPE, BOTH_P, FALLBACK_P, \
5965 NONANSI_P, ATTRS, IMPLICIT, COND) \
5966 if (NAME && COND) \
5967 def_builtin_1 (ENUM, NAME, CLASS, \
5968 builtin_types[(int) TYPE], \
5969 builtin_types[(int) LIBTYPE], \
5970 BOTH_P, FALLBACK_P, NONANSI_P, \
5971 built_in_attributes[(int) ATTRS], IMPLICIT);
5973 #undef DEF_BUILTIN
5974 }
5976 /* ----------------------------------------------------------------------- *
5977 * BUILTIN FUNCTIONS *
5978 * ----------------------------------------------------------------------- */
5980 /* Install the builtin functions we might need. */
5982 void
5984 {
5989 /* Install builtins used by generic middle-end pieces first. Some of these
5990 know about internal specificities and control attributes accordingly, for
5991 instance __builtin_alloca vs no-throw and -fstack-check. We will ignore
5992 the generic definition from builtins.def. */
5995 /* Now, install the target specific builtins, such as the AltiVec family on
5996 ppc, and the common set as exposed by builtins.def. */
5999 }