| blob | b566257e9a4c75274b491d67d47ccd15f9865f9c |
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 ****************************************************************************/
77 /* If nonzero, pretend we are allocating at global level. */
80 /* The default alignment of "double" floating-point types, i.e. floating
81 point types whose size is equal to 64 bits, or 0 if this alignment is
82 not specifically capped. */
85 /* The default alignment of "double" or larger scalar types, i.e. scalar
86 types whose size is greater or equal to 64 bits, or 0 if this alignment
87 is not specifically capped. */
90 /* True if floating-point arithmetics may use wider intermediate results. */
93 /* Tree nodes for the various types and decls we create. */
96 /* Functions to call for each of the possible raise reasons. */
99 /* Likewise, but with extra info for each of the possible raise reasons. */
102 /* Forward declarations for handlers of attributes. */
117 /* Fake handler for attributes we don't properly support, typically because
118 they'd require dragging a lot of the common-c front-end circuitry. */
121 /* Table of machine-independent internal attributes for Ada. We support
122 this minimal set of attributes to accommodate the needs of builtins. */
124 {
125 /* { name, min_len, max_len, decl_req, type_req, fn_type_req, decl_handler,
126 type_handler, affects_type_identity } */
156 /* ??? format and format_arg are heavy and not supported, which actually
157 prevents support for stdio builtins, which we however declare as part
158 of the common builtins.def contents. */
165 };
167 /* Associates a GNAT tree node to a GCC tree node. It is used in
168 `save_gnu_tree', `get_gnu_tree' and `present_gnu_tree'. See documentation
169 of `save_gnu_tree' for more info. */
172 #define GET_GNU_TREE(GNAT_ENTITY) \
173 associate_gnat_to_gnu[(GNAT_ENTITY) - First_Node_Id]
175 #define SET_GNU_TREE(GNAT_ENTITY,VAL) \
176 associate_gnat_to_gnu[(GNAT_ENTITY) - First_Node_Id] = (VAL)
178 #define PRESENT_GNU_TREE(GNAT_ENTITY) \
179 (associate_gnat_to_gnu[(GNAT_ENTITY) - First_Node_Id] != NULL_TREE)
181 /* Associates a GNAT entity to a GCC tree node used as a dummy, if any. */
184 #define GET_DUMMY_NODE(GNAT_ENTITY) \
185 dummy_node_table[(GNAT_ENTITY) - First_Node_Id]
187 #define SET_DUMMY_NODE(GNAT_ENTITY,VAL) \
188 dummy_node_table[(GNAT_ENTITY) - First_Node_Id] = (VAL)
190 #define PRESENT_DUMMY_NODE(GNAT_ENTITY) \
191 (dummy_node_table[(GNAT_ENTITY) - First_Node_Id] != NULL_TREE)
193 /* This variable keeps a table for types for each precision so that we only
194 allocate each of them once. Signed and unsigned types are kept separate.
196 Note that these types are only used when fold-const requests something
197 special. Perhaps we should NOT share these types; we'll see how it
198 goes later. */
201 /* Likewise for float types, but record these by mode. */
204 /* For each binding contour we allocate a binding_level structure to indicate
205 the binding depth. */
208 /* The binding level containing this one (the enclosing binding level). */
210 /* The BLOCK node for this level. */
211 tree block;
212 /* If nonzero, the setjmp buffer that needs to be updated for any
213 variable-sized definition within this context. */
214 tree jmpbuf_decl;
215 };
217 /* The binding level currently in effect. */
220 /* A chain of gnat_binding_level structures awaiting reuse. */
223 /* The context to be used for global declarations. */
226 /* An array of global declarations. */
229 /* An array of builtin function declarations. */
232 /* An array of global renaming pointers. */
235 /* A chain of unused BLOCK nodes. */
238 /* A hash table of padded types. It is modelled on the generic type
239 hash table in tree.c, which must thus be used as a reference. */
243 tree type;
244 };
247 {
251 };
264 /* A linked list used as a queue to defer the initialization of the
265 DECL_CONTEXT attribute of ..._DECL nodes and of the TYPE_CONTEXT attribute
266 of ..._TYPE nodes. */
267 struct deferred_decl_context_node
268 {
273 context to. */
275 };
279 /* Defer the initialization of DECL's DECL_CONTEXT attribute, scheduling to
280 feed it with the elaboration of GNAT_SCOPE. */
284 /* Defer the initialization of TYPE's TYPE_CONTEXT attribute, scheduling to
285 feed it with the DECL_CONTEXT computed as part of N as soon as it is
286 computed. */
288 tree type);
289 \f
290 /* Initialize data structures of the utils.c module. */
292 void
294 {
295 /* Initialize the association of GNAT nodes to GCC trees. */
298 /* Initialize the association of GNAT nodes to GCC trees as dummies. */
301 /* Initialize the hash table of padded types. */
303 }
305 /* Destroy data structures of the utils.c module. */
307 void
309 {
310 /* Destroy the association of GNAT nodes to GCC trees. */
314 /* Destroy the association of GNAT nodes to GCC trees as dummies. */
318 /* Destroy the hash table of padded types. */
322 /* Invalidate the global renaming pointers. */
324 }
325 \f
326 /* GNAT_ENTITY is a GNAT tree node for an entity. Associate GNU_DECL, a GCC
327 tree node, with GNAT_ENTITY. If GNU_DECL is not a ..._DECL node, abort.
328 If NO_CHECK is true, the latter check is suppressed.
330 If GNU_DECL is zero, reset a previous association. */
332 void
334 {
335 /* Check that GNAT_ENTITY is not already defined and that it is being set
336 to something which is a decl. If that is not the case, this usually
337 means GNAT_ENTITY is defined twice, but occasionally is due to some
338 Gigi problem. */
344 }
346 /* GNAT_ENTITY is a GNAT tree node for an entity. Return the GCC tree node
347 that was associated with it. If there is no such tree node, abort.
349 In some cases, such as delayed elaboration or expressions that need to
350 be elaborated only once, GNAT_ENTITY is really not an entity. */
352 tree
354 {
357 }
359 /* Return nonzero if a GCC tree has been associated with GNAT_ENTITY. */
361 bool
363 {
365 }
366 \f
367 /* Make a dummy type corresponding to GNAT_TYPE. */
369 tree
371 {
373 tree gnu_type;
375 /* If there was no equivalent type (can only happen when just annotating
376 types) or underlying type, go back to the original type. */
380 /* If it there already a dummy type, use that one. Else make one. */
384 /* If this is a record, make a RECORD_TYPE or UNION_TYPE; else make
385 an ENUMERAL_TYPE. */
399 }
401 /* Return the dummy type that was made for GNAT_TYPE, if any. */
403 tree
405 {
407 }
409 /* Build dummy fat and thin pointer types whose designated type is specified
410 by GNAT_DESIG_TYPE/GNU_DESIG_TYPE and attach them to the latter. */
412 void
414 {
429 /* Build a stub DECL to trigger the special processing for fat pointer types
430 in gnat_pushdecl. */
433 gnu_fat_type);
441 /* Suppress debug info until after the type is completed. */
450 }
451 \f
452 /* Return true if we are in the global binding level. */
454 bool
456 {
458 }
460 /* Enter a new binding level. */
462 void
464 {
467 /* Reuse a struct for this binding level, if there is one. */
469 {
472 }
473 else
476 /* Use a free BLOCK, if any; otherwise, allocate one. */
478 {
482 }
483 else
486 /* Point the BLOCK we just made to its parent. */
494 /* Add this level to the front of the chain (stack) of active levels. */
498 }
500 /* Set SUPERCONTEXT of the BLOCK for the current binding level to FNDECL
501 and point FNDECL to this BLOCK. */
503 void
505 {
509 }
511 /* Set the jmpbuf_decl for the current binding level to DECL. */
513 void
515 {
517 }
519 /* Get the jmpbuf_decl, if any, for the current binding level. */
521 tree
523 {
525 }
527 /* Exit a binding level. Set any BLOCK into the current code group. */
529 void
531 {
538 /* If this is a function-level BLOCK don't do anything. Otherwise, if there
539 are no variables free the block and merge its subblocks into those of its
540 parent block. Otherwise, add it to the list of its parent. */
542 ;
544 {
550 }
551 else
552 {
557 }
559 /* Free this binding structure. */
563 }
565 /* Exit a binding level and discard the associated BLOCK. */
567 void
569 {
576 /* Free this binding structure. */
580 }
581 \f
582 /* Set the context of TYPE and its parallel types (if any) to CONTEXT. */
584 static void
586 {
592 {
595 /* Give a context to the parallel types and their stub decl, if any.
596 Some parallel types seems to be present in multiple parallel type
597 chains, so don't mess with their context if they already have one. */
599 {
603 }
606 }
607 }
609 /* Return the innermost scope, starting at GNAT_NODE, we are be interested in
610 the debug info, or Empty if there is no such scope. If not NULL, set
611 IS_SUBPROGRAM to whether the returned entity is a subprogram. */
613 static Entity_Id
615 {
616 Entity_Id gnat_entity;
623 else
627 {
629 {
635 /* If the scope is a subprogram, then just rely on
636 current_function_decl, so that we don't have to defer
637 anything. This is needed because other places rely on the
638 validity of the DECL_CONTEXT attribute of FUNCTION_DECL nodes. */
648 /* By default, we are not interested in this particular scope: go to
649 the outer one. */
651 }
653 }
655 }
657 /* If N is NULL, set TYPE's context to CONTEXT. Defer this to the processing of
658 N otherwise. */
660 static void
662 tree context,
664 {
667 else
669 }
671 /* Return global_context. Create it if needed, first. */
673 static tree
675 {
679 }
681 /* Record DECL as belonging to the current lexical scope and use GNAT_NODE
682 for location information and flag propagation. */
684 void
686 {
690 /* If explicitely asked to make DECL global or if it's an imported nested
691 object, short-circuit the regular Scope-based context computation. */
693 {
694 /* Rely on the GNAT scope, or fallback to the current_function_decl if
695 the GNAT scope reached the global scope, if it reached a subprogram
696 or the declaration is a subprogram or a variable (for them we skip
697 intermediate context types because the subprogram body elaboration
698 machinery and the inliner both expect a subprogram context).
700 Falling back to current_function_decl is necessary for implicit
701 subprograms created by gigi, such as the elaboration subprograms. */
703 const Entity_Id gnat_scope
707 && !context_is_subprogram
710 /* Always assume the scope has not been elaborated, thus defer the
711 context propagation to the time its elaboration will be
712 available. */
713 deferred_decl_context
716 /* External declarations (when force_global > 0) may not be in a
717 local context. */
720 }
722 /* If either we are forced to be in global mode or if both the GNAT scope and
723 the current_function_decl did not help determining the context, use the
724 global scope. */
728 /* Functions imported in another function are not really nested.
729 For really nested functions mark them initially as needing
730 a static chain for uses of that flag before unnesting;
731 lower_nested_functions will then recompute it. */
744 /* Set the location of DECL and emit a declaration for it. */
750 /* Put the declaration on the list. The list of declarations is in reverse
751 order. The list will be reversed later. Put global declarations in the
752 globals list and local ones in the current block. But skip TYPE_DECLs
753 for UNCONSTRAINED_ARRAY_TYPE in both cases, as they will cause trouble
754 with the debugger and aren't needed anyway. */
757 {
759 {
762 }
765 else
766 {
769 }
770 }
772 /* For the declaration of a type, set its name if it either is not already
773 set or if the previous type name was not derived from a source name.
774 We'd rather have the type named with a real name and all the pointer
775 types to the same object have the same POINTER_TYPE node. Code in the
776 equivalent function of c-decl.c makes a copy of the type node here, but
777 that may cause us trouble with incomplete types. We make an exception
778 for fat pointer types because the compiler automatically builds them
779 for unconstrained array types and the debugger uses them to represent
780 both these and pointers to these. */
782 {
786 {
787 /* Array and pointer types aren't "tagged" types so we force the
788 type to be associated with its typedef in the DWARF back-end,
789 in order to make sure that the latter is always preserved. */
793 {
800 deferred_decl_context);
803 }
804 }
806 {
807 /* We need a variant for the placeholder machinery to work. */
812 deferred_decl_context);
817 else
821 }
823 ;
824 else
827 /* Propagate the name to all the anonymous variants. This is needed
828 for the type qualifiers machinery to work properly. Also propagate
829 the context to them. Note that the context will be propagated to all
830 parallel types too thanks to gnat_set_type_context. */
834 {
838 deferred_decl_context);
839 }
840 }
841 }
842 \f
843 /* Create a record type that contains a SIZE bytes long field of TYPE with a
844 starting bit position so that it is aligned to ALIGN bits, and leaving at
845 least ROOM bytes free before the field. BASE_ALIGN is the alignment the
846 record is guaranteed to get. GNAT_NODE is used for the position of the
847 associated TYPE_DECL. */
849 tree
852 {
853 /* We will be crafting a record type with one field at a position set to be
854 the next multiple of ALIGN past record'address + room bytes. We use a
855 record placeholder to express record'address. */
859 tree record_addr_st
862 /* The diagram below summarizes the shape of what we manipulate:
864 <--------- pos ---------->
865 { +------------+-------------+-----------------+
866 record =>{ |############| ... | field (type) |
867 { +------------+-------------+-----------------+
868 |<-- room -->|<- voffset ->|<---- size ----->|
869 o o
870 | |
871 record_addr vblock_addr
873 Every length is in sizetype bytes there, except "pos" which has to be
874 set as a bit position in the GCC tree for the record. */
884 /* Compute VOFFSET and then POS. The next byte position multiple of some
885 alignment after some address is obtained by "and"ing the alignment minus
886 1 with the two's complement of the address. */
891 /* POS = (ROOM + VOFFSET) * BIT_PER_UNIT, in bitsizetype. */
895 bitsize_unit_node);
897 /* Craft the GCC record representation. We exceptionally do everything
898 manually here because 1) our generic circuitry is not quite ready to
899 handle the complex position/size expressions we are setting up, 2) we
900 have a strong simplifying factor at hand: we know the maximum possible
901 value of voffset, and 3) we have to set/reset at least the sizes in
902 accordance with this maximum value anyway, as we need them to convey
903 what should be "alloc"ated for this type.
905 Use -1 as the 'addressable' indication for the field to prevent the
906 creation of a bitfield. We don't need one, it would have damaging
907 consequences on the alignment computation, and create_field_decl would
908 make one without this special argument, for instance because of the
909 complex position expression. */
920 bitsize_unit_node),
929 /* Declare it now since it will never be declared otherwise. This is
930 necessary to ensure that its subtrees are properly marked. */
934 }
936 /* TYPE is a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE that is being used
937 as the field type of a packed record if IN_RECORD is true, or as the
938 component type of a packed array if IN_RECORD is false. See if we can
939 rewrite it either as a type that has a non-BLKmode, which we can pack
940 tighter in the packed record case, or as a smaller type. If so, return
941 the new type. If not, return the original type. */
943 tree
945 {
951 /* No point in doing anything if the size is zero. */
957 /* Copy the name and flags from the old type to that of the new.
958 Note that we rely on the pointer equality created here for
959 TYPE_NAME to look through conversions in various places. */
966 /* If we are in a record and have a small size, set the alignment to
967 try for an integral mode. Otherwise set it to try for a smaller
968 type with BLKmode. */
970 {
974 }
975 else
976 {
979 /* Do not try to shrink the size if the RM size is not constant. */
984 /* Round the RM size up to a unit boundary to get the minimal size
985 for a BLKmode record. Give up if it's already the size. */
993 }
997 /* Now copy the fields, keeping the position and size as we don't want
998 to change the layout by propagating the packedness downwards. */
1001 {
1010 /* However, for the last field in a not already packed record type
1011 that is of an aggregate type, we need to use the RM size in the
1012 packable version of the record type, see finish_record_type. */
1020 else
1023 new_field
1036 }
1044 /* If this is a padding record, we never want to make the size smaller
1045 than what was specified. For QUAL_UNION_TYPE, also copy the size. */
1047 {
1051 }
1052 else
1053 {
1057 }
1064 /* Try harder to get a packable type if necessary, for example
1065 in case the record itself contains a BLKmode field. */
1070 /* If neither the mode nor the size has shrunk, return the old type. */
1075 }
1077 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
1078 If TYPE is the best type, return it. Otherwise, make a new type. We
1079 only support new integral and pointer types. FOR_BIASED is true if
1080 we are making a biased type. */
1082 tree
1084 {
1087 tree new_type;
1089 /* If size indicates an error, just return TYPE to avoid propagating
1090 the error. Likewise if it's too large to represent. */
1097 {
1104 /* Integer types with precision 0 are forbidden. */
1108 /* Only do something if the type isn't a packed array type and doesn't
1109 already have the proper size and the size isn't too large. */
1118 else
1123 /* Copy the name to show that it's essentially the same type and
1124 not a subrange type. */
1131 /* Do something if this is a fat pointer, in which case we
1132 may need to return the thin pointer. */
1134 {
1138 return
1139 build_pointer_type_for_mode
1142 }
1146 /* Only do something if this is a thin pointer, in which case we
1147 may need to return the fat pointer. */
1149 return
1155 }
1158 }
1160 /* See if the data pointed to by the hash table slot is marked. */
1162 void
1164 {
1170 else
1172 }
1174 /* Return true iff the padded types are equivalent. */
1176 bool
1178 {
1187 /* We consider that the padded types are equivalent if they pad the same
1188 type and have the same size, alignment and RM size. Taking the mode
1189 into account is redundant since it is determined by the others. */
1190 return
1195 }
1197 /* Look up the padded TYPE in the hash table and return its canonical version
1198 if it exists; otherwise, insert it into the hash table. */
1200 static tree
1202 {
1203 hashval_t hashcode;
1206 hashcode
1223 }
1225 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
1226 if needed. We have already verified that SIZE and ALIGN are large enough.
1227 GNAT_ENTITY is used to name the resulting record and to issue a warning.
1228 IS_COMPONENT_TYPE is true if this is being done for the component type of
1229 an array. IS_USER_TYPE is true if the original type needs to be completed.
1230 DEFINITION is true if this type is being defined. SET_RM_SIZE is true if
1231 the RM size of the resulting type is to be set to SIZE too. */
1233 tree
1237 {
1242 /* If TYPE is a padded type, see if it agrees with any size and alignment
1243 we were given. If so, return the original type. Otherwise, strip
1244 off the padding, since we will either be returning the inner type
1245 or repadding it. If no size or alignment is specified, use that of
1246 the original padded type. */
1248 {
1262 }
1264 /* If the size is either not being changed or is being made smaller (which
1265 is not done here and is only valid for bitfields anyway), show the size
1266 isn't changing. Likewise, clear the alignment if it isn't being
1267 changed. Then return if we aren't doing anything. */
1280 /* If requested, complete the original type and give it a name. */
1287 gnat_entity);
1289 /* We used to modify the record in place in some cases, but that could
1290 generate incorrect debugging information. So make a new record
1291 type and name. */
1303 bitsize_unit_node));
1305 /* If we are changing the alignment and the input type is a record with
1306 BLKmode and a small constant size, try to make a form that has an
1307 integral mode. This might allow the padding record to also have an
1308 integral mode, which will be much more efficient. There is no point
1309 in doing so if a size is specified unless it is also a small constant
1310 size and it is incorrect to do so if we cannot guarantee that the mode
1311 will be naturally aligned since the field must always be addressable.
1313 ??? This might not always be a win when done for a stand-alone object:
1314 since the nominal and the effective type of the object will now have
1315 different modes, a VIEW_CONVERT_EXPR will be required for converting
1316 between them and it might be hard to overcome afterwards, including
1317 at the RTL level when the stand-alone object is accessed as a whole. */
1325 && (!size
1328 {
1333 }
1335 /* Now create the field with the original size. */
1340 /* Do not emit debug info until after the auxiliary record is built. */
1343 /* Set the RM size if requested. */
1345 {
1346 tree canonical_pad_type;
1350 /* If the padded type is complete and has constant size, we canonicalize
1351 it by means of the hash table. This is consistent with the language
1352 semantics and ensures that gigi and the middle-end have a common view
1353 of these padded types. */
1356 {
1359 }
1360 }
1362 /* Unless debugging information isn't being written for the input type,
1363 write a record that shows what we are a subtype of and also make a
1364 variable that indicates our size, if still variable. */
1370 {
1390 }
1394 built:
1395 /* If the size was widened explicitly, maybe give a warning. Take the
1396 original size as the maximum size of the input if there was an
1397 unconstrained record involved and round it up to the specified alignment,
1398 if one was specified. But don't do it if we are just annotating types
1399 and the type is tagged, since tagged types aren't fully laid out in this
1400 mode. */
1420 {
1423 /* For a packed array, post the message on the original array type. */
1434 /* Generate message only for entities that come from source, since
1435 if we have an entity created by expansion, the message will be
1436 generated for some other corresponding source entity. */
1438 {
1447 }
1448 }
1451 }
1452 \f
1453 /* Relate the alias sets of GNU_NEW_TYPE and GNU_OLD_TYPE according to OP.
1454 If this is a multi-dimensional array type, do this recursively.
1456 OP may be
1457 - ALIAS_SET_COPY: the new set is made a copy of the old one.
1458 - ALIAS_SET_SUPERSET: the new set is made a superset of the old one.
1459 - ALIAS_SET_SUBSET: the new set is made a subset of the old one. */
1461 void
1463 {
1464 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
1465 of a one-dimensional array, since the padding has the same alias set
1466 as the field type, but if it's a multi-dimensional array, we need to
1467 see the inner types. */
1473 /* Unconstrained array types are deemed incomplete and would thus be given
1474 alias set 0. Retrieve the underlying array type. */
1476 gnu_old_type
1479 gnu_new_type
1488 {
1490 /* The alias set shouldn't be copied between array types with different
1491 aliasing settings because this can break the aliasing relationship
1492 between the array type and its element type. */
1493 #ifndef ENABLE_CHECKING
1495 #endif
1506 {
1510 /* Do nothing if the alias sets conflict. This ensures that we
1511 never call record_alias_subset several times for the same pair
1512 or at all for alias set 0. */
1514 {
1517 else
1519 }
1520 }
1525 }
1528 }
1529 \f
1530 /* Record TYPE as a builtin type for Ada. NAME is the name of the type.
1531 ARTIFICIAL_P is true if it's a type that was generated by the compiler. */
1533 void
1535 {
1544 }
1545 \f
1546 /* Given a record type RECORD_TYPE and a list of FIELD_DECL nodes FIELD_LIST,
1547 finish constructing the record type as a fat pointer type. */
1549 void
1551 {
1552 /* Make sure we can put it into a register. */
1556 /* Show what it really is. */
1559 /* Do not emit debug info for it since the types of its fields may still be
1560 incomplete at this point. */
1563 /* Force type_contains_placeholder_p to return true on it. Although the
1564 PLACEHOLDER_EXPRs are referenced only indirectly, this isn't a pointer
1565 type but the representation of the unconstrained array. */
1567 }
1569 /* Given a record type RECORD_TYPE and a list of FIELD_DECL nodes FIELD_LIST,
1570 finish constructing the record or union type. If REP_LEVEL is zero, this
1571 record has no representation clause and so will be entirely laid out here.
1572 If REP_LEVEL is one, this record has a representation clause and has been
1573 laid out already; only set the sizes and alignment. If REP_LEVEL is two,
1574 this record is derived from a parent record and thus inherits its layout;
1575 only make a pass on the fields to finalize them. DEBUG_INFO_P is true if
1576 we need to write debug information about this type. */
1578 void
1581 {
1589 tree field;
1593 /* Always attach the TYPE_STUB_DECL for a record type. It is required to
1594 generate debug info and have a parallel type. */
1597 /* Globally initialize the record first. If this is a rep'ed record,
1598 that just means some initializations; otherwise, layout the record. */
1600 {
1609 /* For all-repped records with a size specified, lay the QUAL_UNION_TYPE
1610 out just like a UNION_TYPE, since the size will be fixed. */
1613 }
1614 else
1615 {
1616 /* Ensure there isn't a size already set. There can be in an error
1617 case where there is a rep clause but all fields have errors and
1618 no longer have a position. */
1621 /* Ensure we use the traditional GCC layout for bitfields when we need
1622 to pack the record type or have a representation clause. The other
1623 possible layout (Microsoft C compiler), if available, would prevent
1624 efficient packing in almost all cases. */
1625 #ifdef TARGET_MS_BITFIELD_LAYOUT
1630 ATTR_FLAG_TYPE_IN_PLACE);
1631 #endif
1634 }
1636 /* At this point, the position and size of each field is known. It was
1637 either set before entry by a rep clause, or by laying out the type above.
1639 We now run a pass over the fields (in reverse order for QUAL_UNION_TYPEs)
1640 to compute the Ada size; the GCC size and alignment (for rep'ed records
1641 that are not padding types); and the mode (for rep'ed records). We also
1642 clear the DECL_BIT_FIELD indication for the cases we know have not been
1643 handled yet, and adjust DECL_NONADDRESSABLE_P accordingly. */
1649 {
1653 tree this_ada_size;
1660 else
1663 /* Clear DECL_BIT_FIELD for the cases layout_decl does not handle. */
1666 {
1669 /* In the general case, type alignment is required. */
1671 {
1672 /* The enclosing record type must be sufficiently aligned.
1673 Otherwise, if no alignment was specified for it and it
1674 has been laid out already, bump its alignment to the
1675 desired one if this is compatible with its size. */
1677 {
1680 }
1684 {
1688 }
1689 }
1691 /* In the non-strict alignment case, only byte alignment is. */
1696 }
1698 /* If we still have DECL_BIT_FIELD set at this point, we know that the
1699 field is technically not addressable. Except that it can actually
1700 be addressed if it is BLKmode and happens to be properly aligned. */
1706 /* A type must be as aligned as its most aligned field that is not
1707 a bit-field. But this is already enforced by layout_type. */
1713 {
1720 ada_size
1728 /* Since we know here that all fields are sorted in order of
1729 increasing bit position, the size of the record is one
1730 higher than the ending bit of the last field processed
1731 unless we have a rep clause, since in that case we might
1732 have a field outside a QUAL_UNION_TYPE that has a higher ending
1733 position. So use a MAX in that case. Also, if this field is a
1734 QUAL_UNION_TYPE, we need to take into account the previous size in
1735 the case of empty variants. */
1736 ada_size
1739 size
1746 }
1747 }
1753 {
1754 /* If this is a padding record, we never want to make the size smaller
1755 than what was specified in it, if any. */
1759 /* Now set any of the values we've just computed that apply. */
1765 {
1766 tree size_unit = had_size_unit
1770 bitsize_unit_node));
1778 }
1779 }
1783 }
1785 /* Append PARALLEL_TYPE on the chain of parallel types of TYPE. If
1786 PARRALEL_TYPE has no context and its computation is not deferred yet, also
1787 propagate TYPE's context to PARALLEL_TYPE's or defer its propagation to the
1788 moment TYPE will get a context. */
1790 void
1792 {
1800 /* If PARALLEL_TYPE already has a context, we are done. */
1804 /* Otherwise, try to get one from TYPE's context. */
1806 /* TYPE already has a context, so simply propagate it to PARALLEL_TYPE. */
1809 /* ... otherwise TYPE has not context yet. We know it will thanks to
1810 gnat_pushdecl, and then its context will be propagated to PARALLEL_TYPE.
1811 So we have nothing to do in this case. */
1812 }
1814 /* Return true if TYPE has a parallel type. */
1816 static bool
1818 {
1822 }
1824 /* Wrap up compilation of RECORD_TYPE, i.e. output all the debug information
1825 associated with it. It need not be invoked directly in most cases since
1826 finish_record_type takes care of doing so, but this can be necessary if
1827 a parallel type is to be attached to the record type. */
1829 void
1831 {
1833 tree field;
1835 /* If this is a padded type, the bulk of the debug info has already been
1836 generated for the field's type. */
1840 /* If the type already has a parallel type (XVS type), then we're done. */
1845 {
1846 /* We need to make an XVE/XVU record if any field has variable size,
1847 whether or not the record does. For example, if we have a union,
1848 it may be that all fields, rounded up to the alignment, have the
1849 same size, in which case we'll use that size. But the debug
1850 output routines (except Dwarf2) won't be able to output the fields,
1851 so we need to make the special record. */
1853 /* If a field has a non-constant qualifier, the record will have
1854 variable size too. */
1857 {
1860 }
1861 }
1863 /* If this record type is of variable size, make a parallel record type that
1864 will tell the debugger how the former is laid out (see exp_dbug.ads). */
1866 {
1867 tree new_record_type
1874 new_name
1887 /* Now scan all the fields, replacing each field with a new field
1888 corresponding to the new encoding. */
1891 {
1899 /* We're going to do some pattern matching below so remove as many
1900 conversions as possible. */
1903 /* See how the position was modified from the last position.
1905 There are two basic cases we support: a value was added
1906 to the last position or the last position was rounded to
1907 a boundary and they something was added. Check for the
1908 first case first. If not, see if there is any evidence
1909 of rounding. If so, round the last position and retry.
1911 If this is a union, the position can be taken as zero. */
1914 else
1920 {
1926 }
1931 && tree_fits_uhwi_p
1933 {
1935 unsigned HOST_WIDE_INT addend
1937 align
1943 }
1945 {
1949 }
1951 /* If we can't compute a position, set it to zero.
1953 ??? We really should abort here, but it's too much work
1954 to get this correct for all cases. */
1958 /* See if this type is variable-sized and make a pointer type
1959 and indicate the indirection if so. Beware that the debug
1960 back-end may adjust the position computed above according
1961 to the alignment of the field type, i.e. the pointer type
1962 in this case, if we don't preventively counter that. */
1964 {
1967 {
1970 }
1972 }
1974 /* Make a new field name, if necessary. */
1976 {
1982 else
1986 }
1988 new_field
1994 /* If old_field is a QUAL_UNION_TYPE, take its size as being
1995 zero. The only time it's not the last field of the record
1996 is when there are other components at fixed positions after
1997 it (meaning there was a rep clause for every field) and we
1998 want to be able to encode them. */
2002 ? bitsize_zero_node
2005 }
2010 }
2011 }
2013 /* Utility function of above to merge LAST_SIZE, the previous size of a record
2014 with FIRST_BIT and SIZE that describe a field. SPECIAL is true if this
2015 represents a QUAL_UNION_TYPE in which case we must look for COND_EXPRs and
2016 replace a value of zero with the old size. If HAS_REP is true, we take the
2017 MAX of the end position of this field with LAST_SIZE. In all other cases,
2018 we use FIRST_BIT plus SIZE. Return an expression for the size. */
2020 static tree
2023 {
2025 tree new_size;
2028 {
2032 }
2034 else
2045 /* We don't need any NON_VALUE_EXPRs and they can confuse us (especially
2046 when fed through substitute_in_expr) into thinking that a constant
2047 size is not constant. */
2052 }
2054 /* Utility function of above to see if OP0 and OP1, both of SIZETYPE, are
2055 related by the addition of a constant. Return that constant if so. */
2057 static tree
2059 {
2069 else
2071 }
2073 /* Utility function of above to split a tree OP which may be a sum, into a
2074 constant part, which is returned, and a variable part, which is stored
2075 in *PVAR. *PVAR may be bitsize_zero_node. All operations must be of
2076 bitsizetype. */
2078 static tree
2080 {
2081 /* Strip conversions in order to ease the tree traversal and maximize the
2082 potential for constant or plus/minus discovery. We need to be careful
2083 to always return and set *pvar to bitsizetype trees, but it's worth
2084 the effort. */
2090 {
2093 }
2095 {
2106 }
2107 else
2109 }
2110 \f
2111 /* Return a FUNCTION_TYPE node. RETURN_TYPE is the type returned by the
2112 subprogram. If it is VOID_TYPE, then we are dealing with a procedure,
2113 otherwise we are dealing with a function. PARAM_DECL_LIST is a list of
2114 PARM_DECL nodes that are the subprogram parameters. CICO_LIST is the
2115 copy-in/copy-out list to be stored into the TYPE_CICO_LIST field.
2116 RETURN_UNCONSTRAINED_P is true if the function returns an unconstrained
2117 object. RETURN_BY_DIRECT_REF_P is true if the function returns by direct
2118 reference. RETURN_BY_INVISI_REF_P is true if the function returns by
2119 invisible reference. */
2121 tree
2125 {
2126 /* A list of the data type nodes of the subprogram formal parameters.
2127 This list is generated by traversing the input list of PARM_DECL
2128 nodes. */
2137 /* TYPE may have been shared since GCC hashes types. If it has a different
2138 CICO_LIST, make a copy. Likewise for the various flags. */
2141 {
2147 }
2150 }
2151 \f
2152 /* Return a copy of TYPE but safe to modify in any way. */
2154 tree
2156 {
2159 /* Unshare the language-specific data. */
2161 {
2164 }
2166 /* And the contents of the language-specific slot if needed. */
2169 {
2174 }
2176 /* copy_node clears this field instead of copying it, because it is
2177 aliased with TREE_CHAIN. */
2186 }
2187 \f
2188 /* Return a subtype of sizetype with range MIN to MAX and whose
2189 TYPE_INDEX_TYPE is INDEX. GNAT_NODE is used for the position
2190 of the associated TYPE_DECL. */
2192 tree
2194 {
2195 /* First build a type for the desired range. */
2198 /* Then set the index type. */
2203 }
2205 /* Return a subtype of TYPE with range MIN to MAX. If TYPE is NULL,
2206 sizetype is used. */
2208 tree
2210 {
2211 tree range_type;
2216 /* First build a type with the base range. */
2220 /* Then set the actual range. */
2225 }
2226 \f
2227 /* Return a TYPE_DECL node suitable for the TYPE_STUB_DECL field of a type.
2228 TYPE_NAME gives the name of the type and TYPE is a ..._TYPE node giving
2229 its data type. */
2231 tree
2233 {
2234 /* Using a named TYPE_DECL ensures that a type name marker is emitted in
2235 STABS while setting DECL_ARTIFICIAL ensures that no DW_TAG_typedef is
2236 emitted in DWARF. */
2241 }
2243 /* Return a TYPE_DECL node. TYPE_NAME gives the name of the type and TYPE
2244 is a ..._TYPE node giving its data type. ARTIFICIAL_P is true if this
2245 is a declaration that was generated by the compiler. DEBUG_INFO_P is
2246 true if we need to write debug information about this type. GNAT_NODE
2247 is used for the position of the decl. */
2249 tree
2252 {
2255 tree type_decl;
2257 /* Only the builtin TYPE_STUB_DECL should be used for dummy types. */
2260 /* If the type hasn't been named yet, we're naming it; preserve an existing
2261 TYPE_STUB_DECL that has been attached to it for some purpose. */
2263 {
2266 }
2267 else
2273 /* Add this decl to the current binding level. */
2276 /* If we're naming the type, equate the TYPE_STUB_DECL to the name.
2277 This causes the name to be also viewed as a "tag" by the debug
2278 back-end, with the advantage that no DW_TAG_typedef is emitted
2279 for artificial "tagged" types in DWARF. */
2283 /* Do not generate debug info for UNCONSTRAINED_ARRAY_TYPE that the
2284 back-end doesn't support, and for others if we don't need to. */
2289 }
2290 \f
2291 /* Return a VAR_DECL or CONST_DECL node.
2293 VAR_NAME gives the name of the variable. ASM_NAME is its assembler name
2294 (if provided). TYPE is its data type (a GCC ..._TYPE node). VAR_INIT is
2295 the GCC tree for an optional initial expression; NULL_TREE if none.
2297 CONST_FLAG is true if this variable is constant, in which case we might
2298 return a CONST_DECL node unless CONST_DECL_ALLOWED_P is false.
2300 PUBLIC_FLAG is true if this is for a reference to a public entity or for a
2301 definition to be made visible outside of the current compilation unit, for
2302 instance variable definitions in a package specification.
2304 EXTERN_FLAG is true when processing an external variable declaration (as
2305 opposed to a definition: no storage is to be allocated for the variable).
2307 STATIC_FLAG is only relevant when not at top level. In that case
2308 it indicates whether to always allocate storage to the variable.
2310 GNAT_NODE is used for the position of the decl. */
2312 tree
2317 {
2318 /* Whether the object has static storage duration, either explicitly or by
2319 virtue of being declared at the global level. */
2322 /* Whether the initializer is constant: for an external object or an object
2323 with static storage duration, we check that the initializer is a valid
2324 constant expression for initializing a static variable; otherwise, we
2325 only check that it is constant. */
2326 const bool init_const
2327 = (var_init
2331 != NULL_TREE
2334 /* Whether we will make TREE_CONSTANT the DECL we produce here, in which
2335 case the initializer may be used in lieu of the DECL node (as done in
2336 Identifier_to_gnu). This is useful to prevent the need of elaboration
2337 code when an identifier for which such a DECL is made is in turn used
2338 as an initializer. We used to rely on CONST_DECL vs VAR_DECL for this,
2339 but extra constraints apply to this choice (see below) and they are not
2340 relevant to the distinction we wish to make. */
2343 /* The actual DECL node. CONST_DECL was initially intended for enumerals
2344 and may be used for scalars in general but not for aggregates. */
2345 tree var_decl
2351 /* If this is external, throw away any initializations (they will be done
2352 elsewhere) unless this is a constant for which we would like to remain
2353 able to get the initializer. If we are defining a global here, leave a
2354 constant initialization and save any variable elaborations for the
2355 elaboration routine. If we are just annotating types, throw away the
2356 initialization if it isn't a constant. */
2361 /* At the global level, a non-constant initializer generates elaboration
2362 statements. Check that such statements are allowed, that is to say,
2363 not violating a No_Elaboration_Code restriction. */
2372 /* We need to allocate static storage for an object with static storage
2373 duration if it isn't external. */
2376 /* The object is public if it is external or if it is declared public
2377 and has static storage duration. */
2380 /* Ada doesn't feature Fortran-like COMMON variables so we shouldn't
2381 try to fiddle with DECL_COMMON. However, on platforms that don't
2382 support global BSS sections, uninitialized global variables would
2383 go in DATA instead, thus increasing the size of the executable. */
2390 /* For an external constant whose initializer is not absolute, do not emit
2391 debug info. In DWARF this would mean a global relocation in a read-only
2392 section which runs afoul of the PE-COFF run-time relocation mechanism. */
2394 && constant_p
2395 && var_init
2406 /* ??? Some attributes cannot be applied to CONST_DECLs. */
2410 /* Add this decl to the current binding level. */
2414 {
2420 }
2423 }
2424 \f
2425 /* Return true if TYPE, an aggregate type, contains (or is) an array. */
2427 static bool
2429 {
2431 {
2435 {
2436 tree field;
2442 }
2449 }
2450 }
2452 /* Return a FIELD_DECL node. FIELD_NAME is the field's name, FIELD_TYPE is
2453 its type and RECORD_TYPE is the type of the enclosing record. If SIZE is
2454 nonzero, it is the specified size of the field. If POS is nonzero, it is
2455 the bit position. PACKED is 1 if the enclosing record is packed, -1 if it
2456 has Component_Alignment of Storage_Unit. If ADDRESSABLE is nonzero, it
2457 means we are allowed to take the address of the field; if it is negative,
2458 we should not make a bitfield, which is used by make_aligning_type. */
2460 tree
2463 {
2470 /* If FIELD_TYPE is BLKmode, we must ensure this is aligned to at least a
2471 byte boundary since GCC cannot handle less-aligned BLKmode bitfields.
2472 Likewise for an aggregate without specified position that contains an
2473 array, because in this case slices of variable length of this array
2474 must be handled by GCC and variable-sized objects need to be aligned
2475 to at least a byte boundary. */
2477 || (!pos
2482 /* If a size is specified, use it. Otherwise, if the record type is packed
2483 compute a size to use, which may differ from the object's natural size.
2484 We always set a size in this case to trigger the checks for bitfield
2485 creation below, which is typically required when no position has been
2486 specified. */
2490 {
2494 }
2496 /* If we may, according to ADDRESSABLE, make a bitfield if a size is
2497 specified for two reasons: first if the size differs from the natural
2498 size. Second, if the alignment is insufficient. There are a number of
2499 ways the latter can be true.
2501 We never make a bitfield if the type of the field has a nonconstant size,
2502 because no such entity requiring bitfield operations should reach here.
2504 We do *preventively* make a bitfield when there might be the need for it
2505 but we don't have all the necessary information to decide, as is the case
2506 of a field with no specified position in a packed record.
2508 We also don't look at STRICT_ALIGNMENT here, and rely on later processing
2509 in layout_decl or finish_record_type to clear the bit_field indication if
2510 it is in fact not needed. */
2512 && size
2517 || packed
2520 {
2524 {
2528 else
2530 }
2531 }
2535 /* Bump the alignment if need be, either for bitfield/packing purposes or
2536 to satisfy the type requirements if no such consideration applies. When
2537 we get the alignment from the type, indicate if this is from an explicit
2538 user request, which prevents stor-layout from lowering it later on. */
2539 {
2540 unsigned int bit_align
2547 {
2550 }
2551 }
2554 {
2555 /* We need to pass in the alignment the DECL is known to have.
2556 This is the lowest-order bit set in POS, but no more than
2557 the alignment of the record, if one is specified. Note
2558 that an alignment of 0 is taken as infinite. */
2563 else
2577 }
2579 /* In addition to what our caller says, claim the field is addressable if we
2580 know that its type is not suitable.
2582 The field may also be "technically" nonaddressable, meaning that even if
2583 we attempt to take the field's address we will actually get the address
2584 of a copy. This is the case for true bitfields, but the DECL_BIT_FIELD
2585 value we have at this point is not accurate enough, so we don't account
2586 for this here and let finish_record_type decide. */
2593 }
2594 \f
2595 /* Return a PARM_DECL node. PARAM_NAME is the name of the parameter and
2596 PARAM_TYPE is its type. READONLY is true if the parameter is readonly
2597 (either an In parameter or an address of a pass-by-ref parameter). */
2599 tree
2601 {
2605 /* Honor TARGET_PROMOTE_PROTOTYPES like the C compiler, as not doing so
2606 can lead to various ABI violations. */
2610 {
2611 /* We have to be careful about biased types here. Make a subtype
2612 of integer_type_node with the proper biasing. */
2615 {
2616 tree subtype
2623 }
2624 else
2626 }
2631 }
2632 \f
2633 /* Process the attributes in ATTR_LIST for NODE, which is either a DECL or
2634 a TYPE. If IN_PLACE is true, the tree pointed to by NODE should not be
2635 changed. GNAT_NODE is used for the position of error messages. */
2637 void
2639 Node_Id gnat_node)
2640 {
2645 {
2651 else
2658 {
2661 }
2667 else
2674 {
2677 }
2678 else
2697 }
2700 }
2701 \f
2702 /* Record DECL as a global renaming pointer. */
2704 void
2706 {
2709 }
2711 /* Invalidate the global renaming pointers that are not constant, lest their
2712 renamed object contains SAVE_EXPRs tied to an elaboration routine. Note
2713 that we should not blindly invalidate everything here because of the need
2714 to propagate constant values through renaming. */
2716 void
2718 {
2720 tree iter;
2730 }
2732 /* Return true if VALUE is a known to be a multiple of FACTOR, which must be
2733 a power of 2. */
2735 bool
2737 {
2746 }
2748 /* Return whether GNAT_NODE is a defining identifier for a renaming that comes
2749 from the parameter association for the instantiation of a generic. We do
2750 not want to emit source location for them: the code generated for their
2751 initialization is likely to disturb debugging. */
2753 bool
2755 {
2762 /* Get the object declaration of the renamed object, if any and if the
2763 renamed object is a mere identifier. */
2773 return
2777 }
2779 /* Defer the initialization of DECL's DECL_CONTEXT attribute, scheduling to
2780 feed it with the elaboration of GNAT_SCOPE. */
2784 {
2787 new_node
2796 }
2798 /* Defer the initialization of TYPE's TYPE_CONTEXT attribute, scheduling to
2799 feed it with the DECL_CONTEXT computed as part of N as soon as it is
2800 computed. */
2802 static void
2804 {
2806 }
2808 /* Get the GENERIC node corresponding to GNAT_SCOPE, if available. Return
2809 NULL_TREE if it is not available. */
2811 static tree
2813 {
2814 tree context;
2818 else
2822 {
2825 /* Skip dummy types: only the final ones can appear in the context
2826 chain. */
2830 /* ..._TYPE nodes are more useful than TYPE_DECL nodes in the context
2831 chain. */
2832 else
2834 }
2837 }
2839 /* Try to process all deferred nodes in the queue. Keep in the queue the ones
2840 that cannot be processed yet, remove the other ones. If FORCE is true,
2841 force the processing for all nodes, use the global context when nodes don't
2842 have a GNU translation. */
2844 void
2846 {
2851 {
2854 Entity_Id gnat_scope;
2858 /* If FORCE, get the innermost elaborated scope. Otherwise, just try to
2859 get the first scope. */
2862 {
2867 }
2869 /* Imported declarations must not be in a local context (i.e. not inside
2870 a function). */
2872 {
2876 {
2881 }
2882 }
2884 /* If FORCE, we want to get rid of all nodes in the queue: in case there
2885 was no elaborated scope, use the global context. */
2890 {
2891 tree t;
2896 /* Propagate it to the TYPE_CONTEXT attributes of the requested
2897 ..._TYPE nodes. */
2899 {
2901 }
2903 }
2905 /* If this node has been successfuly processed, remove it from the
2906 queue. Then move to the next node. */
2908 {
2912 }
2913 else
2915 }
2916 }
2919 /* Return VALUE scaled by the biggest power-of-2 factor of EXPR. */
2921 static unsigned int
2923 {
2926 /* An expression which is a bitwise AND with a mask has a power-of-2 factor
2927 corresponding to the number of trailing zeros of the mask. */
2930 {
2935 {
2938 i++;
2939 }
2940 }
2943 }
2945 /* Given two consecutive field decls PREV_FIELD and CURR_FIELD, return true
2946 unless we can prove these 2 fields are laid out in such a way that no gap
2947 exist between the end of PREV_FIELD and the beginning of CURR_FIELD. OFFSET
2948 is the distance in bits between the end of PREV_FIELD and the starting
2949 position of CURR_FIELD. It is ignored if null. */
2951 static bool
2953 {
2954 /* If this is the first field of the record, there cannot be any gap */
2958 /* If the previous field is a union type, then return false: The only
2959 time when such a field is not the last field of the record is when
2960 there are other components at fixed positions after it (meaning there
2961 was a rep clause for every field), in which case we don't want the
2962 alignment constraint to override them. */
2966 /* If the distance between the end of prev_field and the beginning of
2967 curr_field is constant, then there is a gap if the value of this
2968 constant is not null. */
2972 /* If the size and position of the previous field are constant,
2973 then check the sum of this size and position. There will be a gap
2974 iff it is not multiple of the current field alignment. */
2981 /* If both the position and size of the previous field are multiples
2982 of the current field alignment, there cannot be any gap. */
2987 /* Fallback, return that there may be a potential gap */
2989 }
2991 /* Return a LABEL_DECL with LABEL_NAME. GNAT_NODE is used for the position
2992 of the decl. */
2994 tree
2996 {
2997 tree label_decl
3002 /* Add this decl to the current binding level. */
3006 }
3007 \f
3008 /* Return a FUNCTION_DECL node. SUBPROG_NAME is the name of the subprogram,
3009 ASM_NAME is its assembler name, SUBPROG_TYPE is its type (a FUNCTION_TYPE
3010 node), PARAM_DECL_LIST is the list of the subprogram arguments (a list of
3011 PARM_DECL nodes chained through the DECL_CHAIN field).
3013 INLINE_STATUS, PUBLIC_FLAG, EXTERN_FLAG, ARTIFICIAL_FLAG and ATTR_LIST are
3014 used to set the appropriate fields in the FUNCTION_DECL. GNAT_NODE is
3015 used for the position of the decl. */
3017 tree
3022 {
3024 subprog_type);
3033 {
3046 ATTR_FLAG_TYPE_IN_PLACE);
3048 /* ... fall through ... */
3057 }
3070 {
3073 /* The expand_main_function circuitry expects "main_identifier_node" to
3074 designate the DECL_NAME of the 'main' entry point, in turn expected
3075 to be declared as the "main" function literally by default. Ada
3076 program entry points are typically declared with a different name
3077 within the binder generated file, exported as 'main' to satisfy the
3078 system expectations. Force main_identifier_node in this case. */
3081 }
3085 /* Add this decl to the current binding level. */
3088 /* Output the assembler code and/or RTL for the declaration. */
3092 }
3093 \f
3094 /* Set up the framework for generating code for SUBPROG_DECL, a subprogram
3095 body. This routine needs to be invoked before processing the declarations
3096 appearing in the subprogram. */
3098 void
3100 {
3101 tree param_decl;
3105 /* This function is being defined. */
3110 /* Enter a new binding level and show that all the parameters belong to
3111 this function. */
3119 }
3121 /* Finish translating the current subprogram and set its BODY. */
3123 void
3125 {
3128 /* Attach the BLOCK for this level to the function and pop the level. */
3133 /* Mark the RESULT_DECL as being in this subprogram. */
3136 /* The body should be a BIND_EXPR whose BLOCK is the top-level one. */
3138 {
3141 }
3146 }
3148 /* Wrap up compilation of SUBPROG_DECL, a subprogram body. */
3150 void
3152 {
3153 /* We cannot track the location of errors past this point. */
3156 /* If we're only annotating types, don't actually compile this function. */
3160 /* Dump functions before gimplification. */
3165 else
3166 /* Register this function with cgraph just far enough to get it
3167 added to our parent's nested function list. */
3169 }
3171 tree
3173 {
3176 }
3178 /* Return an integer type with the number of bits of precision given by
3179 PRECISION. UNSIGNEDP is nonzero if the type is unsigned; otherwise
3180 it is a signed type. */
3182 tree
3184 {
3185 tree t;
3194 else
3201 {
3204 }
3207 }
3209 /* Likewise for floating-point types. */
3211 static tree
3213 {
3214 tree t;
3226 {
3229 }
3232 }
3234 /* Return a data type that has machine mode MODE. UNSIGNEDP selects
3235 an unsigned type; otherwise a signed type is returned. */
3237 tree
3239 {
3256 {
3261 }
3264 }
3266 /* Return the unsigned version of a TYPE_NODE, a scalar type. */
3268 tree
3270 {
3274 {
3277 }
3281 {
3284 }
3287 }
3289 /* Return the signed version of a TYPE_NODE, a scalar type. */
3291 tree
3293 {
3297 {
3300 }
3304 {
3307 }
3310 }
3312 /* Return 1 if the types T1 and T2 are compatible, i.e. if they can be
3313 transparently converted to each other. */
3315 int
3317 {
3320 /* This is the default criterion. */
3324 /* We only check structural equivalence here. */
3328 /* Vector types are also compatible if they have the same number of subparts
3329 and the same form of (scalar) element type. */
3336 /* Array types are also compatible if they are constrained and have the same
3337 domain(s) and the same component type. */
3352 }
3354 /* Return true if EXPR is a useless type conversion. */
3356 bool
3358 {
3366 }
3368 /* Return true if T, a FUNCTION_TYPE, has the specified list of flags. */
3370 bool
3373 {
3378 }
3379 \f
3380 /* EXP is an expression for the size of an object. If this size contains
3381 discriminant references, replace them with the maximum (if MAX_P) or
3382 minimum (if !MAX_P) possible value of the discriminant. */
3384 tree
3386 {
3391 {
3398 {
3412 }
3416 /* If this contains a PLACEHOLDER_EXPR, it is the thing we want to
3417 modify. Otherwise, we treat it like a variable. */
3419 {
3423 }
3439 {
3444 /* Special-case wanting the maximum value of a MIN_EXPR.
3445 In that case, if one side overflows, return the other. */
3447 {
3453 }
3455 /* Likewise, handle a MINUS_EXPR or PLUS_EXPR with the LHS
3456 overflowing and the RHS a variable. */
3464 }
3468 {
3492 }
3494 /* Other tree classes cannot happen. */
3497 }
3500 }
3501 \f
3502 /* Build a template of type TEMPLATE_TYPE from the array bounds of ARRAY_TYPE.
3503 EXPR is an expression that we can use to locate any PLACEHOLDER_EXPRs.
3504 Return a constructor for the template. */
3506 tree
3508 {
3511 tree field;
3523 /* First make the list for a CONSTRUCTOR for the template. Go down the
3524 field list of the template instead of the type chain because this
3525 array might be an Ada array of arrays and we can't tell where the
3526 nested arrays stop being the underlying object. */
3529 (bound_list
3533 {
3536 /* If we have a bound list, get the bounds from there. Likewise
3537 for an ARRAY_TYPE. Otherwise, if expr is a PARM_DECL with
3538 DECL_BY_COMPONENT_PTR_P, use the bounds of the field in the template.
3539 This will give us a maximum range. */
3547 else
3553 /* If either MIN or MAX involve a PLACEHOLDER_EXPR, we must
3554 substitute it from OBJECT. */
3560 }
3563 }
3564 \f
3565 /* Return true if TYPE is suitable for the element type of a vector. */
3567 static bool
3569 {
3570 machine_mode mode;
3584 }
3586 /* Return a vector type given the SIZE and the INNER_TYPE, or NULL_TREE if
3587 this is not possible. If ATTRIBUTE is non-zero, we are processing the
3588 attribute declaration and want to issue error messages on failure. */
3590 static tree
3592 {
3596 /* Silently punt on variable sizes. We can't make vector types for them,
3597 need to ignore them on front-end generated subtypes of unconstrained
3598 base types, and this attribute is for binding implementors, not end
3599 users, so we should never get there from legitimate explicit uses. */
3605 {
3610 }
3614 {
3618 }
3621 {
3625 }
3629 {
3633 }
3636 }
3638 /* Return a vector type whose representative array type is ARRAY_TYPE, or
3639 NULL_TREE if this is not possible. If ATTRIBUTE is non-zero, we are
3640 processing the attribute and want to issue error messages on failure. */
3642 static tree
3644 {
3647 attribute);
3653 }
3654 \f
3655 /* Build a type to be used to represent an aliased object whose nominal type
3656 is an unconstrained array. This consists of a RECORD_TYPE containing a
3657 field of TEMPLATE_TYPE and a field of OBJECT_TYPE, which is an ARRAY_TYPE.
3658 If ARRAY_TYPE is that of an unconstrained array, this is used to represent
3659 an arbitrary unconstrained object. Use NAME as the name of the record.
3660 DEBUG_INFO_P is true if we need to write debug information for the type. */
3662 tree
3665 {
3666 tree decl;
3668 tree template_field
3671 tree array_field
3680 /* Declare it now since it will never be declared otherwise. This is
3681 necessary to ensure that its subtrees are properly marked. */
3684 /* template_type will not be used elsewhere than here, so to keep the debug
3685 info clean and in order to avoid scoping issues, make decl its
3686 context. */
3690 }
3692 /* Same, taking a thin or fat pointer type instead of a template type. */
3694 tree
3697 {
3698 tree template_type;
3702 template_type
3707 return
3709 }
3710 \f
3711 /* Update anything previously pointing to OLD_TYPE to point to NEW_TYPE.
3712 In the normal case this is just two adjustments, but we have more to
3713 do if NEW_TYPE is an UNCONSTRAINED_ARRAY_TYPE. */
3715 void
3717 {
3720 tree t;
3722 /* If this is the main variant, process all the other variants first. */
3727 /* If no pointers and no references, we are done. */
3731 /* Merge the old type qualifiers in the new type.
3733 Each old variant has qualifiers for specific reasons, and the new
3734 designated type as well. Each set of qualifiers represents useful
3735 information grabbed at some point, and merging the two simply unifies
3736 these inputs into the final type description.
3738 Consider for instance a volatile type frozen after an access to constant
3739 type designating it; after the designated type's freeze, we get here with
3740 a volatile NEW_TYPE and a dummy OLD_TYPE with a readonly variant, created
3741 when the access type was processed. We will make a volatile and readonly
3742 designated type, because that's what it really is.
3744 We might also get here for a non-dummy OLD_TYPE variant with different
3745 qualifiers than those of NEW_TYPE, for instance in some cases of pointers
3746 to private record type elaboration (see the comments around the call to
3747 this routine in gnat_to_gnu_entity <E_Access_Type>). We have to merge
3748 the qualifiers in those cases too, to avoid accidentally discarding the
3749 initial set, and will often end up with OLD_TYPE == NEW_TYPE then. */
3750 new_type
3754 /* If old type and new type are identical, there is nothing to do. */
3758 /* Otherwise, first handle the simple case. */
3760 {
3763 /* If pointer or reference already points to new type, nothing to do.
3764 This can happen as update_pointer_to can be invoked multiple times
3765 on the same couple of types because of the type variants. */
3770 /* Chain PTR and its variants at the end. */
3773 {
3777 }
3778 else
3781 /* Now adjust them. */
3784 {
3788 }
3790 /* Chain REF and its variants at the end. */
3793 {
3797 }
3798 else
3801 /* Now adjust them. */
3808 }
3810 /* Now deal with the unconstrained array case. In this case the pointer
3811 is actually a record where both fields are pointers to dummy nodes.
3812 Turn them into pointers to the correct types using update_pointer_to.
3813 Likewise for the pointer to the object record (thin pointer). */
3814 else
3815 {
3820 /* If PTR already points to NEW_TYPE, nothing to do. This can happen
3821 since update_pointer_to can be invoked multiple times on the same
3822 couple of types because of the type variants. */
3826 update_pointer_to
3830 update_pointer_to
3838 }
3839 }
3840 \f
3841 /* Convert EXPR, a pointer to a constrained array, into a pointer to an
3842 unconstrained one. This involves making or finding a template. */
3844 static tree
3846 {
3850 tree template_addr;
3854 /* If EXPR is null, make a fat pointer that contains a null pointer to the
3855 array (compare_fat_pointers ensures that this is the full discriminant)
3856 and a valid pointer to the bounds. This latter property is necessary
3857 since the compiler can hoist the load of the bounds done through it. */
3859 {
3865 else
3866 {
3867 /* The template type can still be dummy at this point so we build an
3868 empty constructor. The middle-end will fill it in with zeros. */
3873 }
3879 /* Do not set TREE_CONSTANT so as to force T to static memory. */
3884 }
3886 /* If EXPR is a thin pointer, make template and data from the record. */
3888 {
3893 /* If we have a TYPE_UNCONSTRAINED_ARRAY attached to the RECORD_TYPE,
3894 the thin pointer value has been shifted so we shift it back to get
3895 the template address. */
3897 {
3898 template_addr
3901 byte_position
3903 template_addr
3905 template_addr);
3906 }
3908 /* Otherwise we explicitly take the address of the fields. */
3909 else
3910 {
3912 template_addr
3920 }
3921 }
3923 /* Otherwise, build the constructor for the template. */
3924 else
3925 template_addr
3928 expr));
3930 /* The final result is a constructor for the fat pointer.
3932 If EXPR is an argument of a foreign convention subprogram, the type it
3933 points to is directly the component type. In this case, the expression
3934 type may not match the corresponding FIELD_DECL type at this point, so we
3935 call "convert" here to fix that up if necessary. This type consistency is
3936 required, for instance because it ensures that possible later folding of
3937 COMPONENT_REFs against this constructor always yields something of the
3938 same type as the initial reference.
3940 Note that the call to "build_template" above is still fine because it
3941 will only refer to the provided TEMPLATE_TYPE in this case. */
3945 }
3946 \f
3947 /* Create an expression whose value is that of EXPR,
3948 converted to type TYPE. The TREE_TYPE of the value
3949 is always TYPE. This function implements all reasonable
3950 conversions; callers should filter out those that are
3951 not permitted by the language being compiled. */
3953 tree
3955 {
3960 /* If the expression is already of the right type, we are done. */
3964 /* If both input and output have padding and are of variable size, do this
3965 as an unchecked conversion. Likewise if one is a mere variant of the
3966 other, so we avoid a pointless unpad/repad sequence. */
3974 ;
3976 /* If the output type has padding, convert to the inner type and make a
3977 constructor to build the record, unless a variable size is involved. */
3979 {
3982 /* If we previously converted from another type and our type is
3983 of variable size, remove the conversion to avoid the need for
3984 variable-sized temporaries. Likewise for a conversion between
3985 original and packable version. */
3993 /* If we are just removing the padding from expr, convert the original
3994 object if we have variable size in order to avoid the need for some
3995 variable-sized temporaries. Likewise if the padding is a variant
3996 of the other, so we avoid a pointless unpad/repad sequence. */
4007 /* If the inner type is of self-referential size and the expression type
4008 is a record, do this as an unchecked conversion. But first pad the
4009 expression if possible to have the same size on both sides. */
4012 {
4016 expr);
4018 }
4020 /* If we are converting between array types with variable size, do the
4021 final conversion as an unchecked conversion, again to avoid the need
4022 for some variable-sized temporaries. If valid, this conversion is
4023 very likely purely technical and without real effects. */
4030 expr),
4037 }
4039 /* If the input type has padding, remove it and convert to the output type.
4040 The conditions ordering is arranged to ensure that the output type is not
4041 a padding type here, as it is not clear whether the conversion would
4042 always be correct if this was to happen. */
4044 {
4045 tree unpadded;
4047 /* If we have just converted to this padded type, just get the
4048 inner expression. */
4054 /* Otherwise, build an explicit component reference. */
4055 else
4056 unpadded
4060 }
4062 /* If the input is a biased type, adjust first. */
4069 /* If the input is a justified modular type, we need to extract the actual
4070 object before converting it to any other type with the exceptions of an
4071 unconstrained array or of a mere type variant. It is useful to avoid the
4072 extraction and conversion in the type variant case because it could end
4073 up replacing a VAR_DECL expr by a constructor and we might be about the
4074 take the address of the result. */
4081 /* If converting to a type that contains a template, convert to the data
4082 type and then build the template. */
4084 {
4089 /* If the source already has a template, get a reference to the
4090 associated array only, as we are going to rebuild a template
4091 for the target type anyway. */
4100 }
4102 /* There are some cases of expressions that we process specially. */
4104 {
4109 /* Just set its type here. For TRANSFORM_EXPR, we will do the actual
4110 conversion in gnat_expand_expr. NULL_EXPR does not represent
4111 and actual value, so no conversion is needed. */
4117 /* If we are converting a STRING_CST to another constrained array type,
4118 just make a new one in the proper type. */
4122 {
4126 }
4130 /* If we are converting a VECTOR_CST to a mere type variant, just make
4131 a new one in the proper type. */
4133 {
4137 }
4140 /* If we are converting a CONSTRUCTOR to a mere type variant, or to
4141 another padding type around the same type, just make a new one in
4142 the proper type. */
4149 {
4154 }
4156 /* Likewise for a conversion between original and packable version, or
4157 conversion between types of the same size and with the same list of
4158 fields, but we have to work harder to preserve type consistency. */
4164 {
4173 /* Whether we need to clear TREE_CONSTANT et al. on the output
4174 constructor when we convert in place. */
4178 {
4179 /* Skip the missing fields in the CONSTRUCTOR. */
4181 {
4184 }
4185 /* The field must be the same. */
4188 constructor_elt elt
4192 /* If packing has made this field a bitfield and the input
4193 value couldn't be emitted statically any more, we need to
4194 clear TREE_CONSTANT on our output. */
4204 }
4206 /* If we have been able to match and convert all the input fields
4207 to their output type, convert in place now. We'll fallback to a
4208 view conversion downstream otherwise. */
4210 {
4217 }
4218 }
4220 /* Likewise for a conversion between array type and vector type with a
4221 compatible representative array. */
4225 etype))
4226 {
4231 tree value;
4233 /* Build a VECTOR_CST from a *constant* array constructor. */
4235 {
4238 /* Iterate through elements and check if all constructor
4239 elements are *_CSTs. */
4242 {
4245 }
4250 }
4252 /* Otherwise, build a regular vector constructor. */
4255 {
4258 }
4263 }
4267 /* First retrieve the underlying array. */
4274 {
4275 /* GCC 4.x is very sensitive to type consistency overall, and view
4276 conversions thus are very frequent. Even though just "convert"ing
4277 the inner operand to the output type is fine in most cases, it
4278 might expose unexpected input/output type mismatches in special
4279 circumstances so we avoid such recursive calls when we can. */
4282 /* If we are converting back to the original type, we can just
4283 lift the input conversion. This is a common occurrence with
4284 switches back-and-forth amongst type variants. */
4288 /* Otherwise, if we're converting between two aggregate or vector
4289 types, we might be allowed to substitute the VIEW_CONVERT_EXPR
4290 target type in place or to just convert the inner expression. */
4293 {
4294 /* If we are converting between mere variants, we can just
4295 substitute the VIEW_CONVERT_EXPR in place. */
4299 /* Otherwise, we may just bypass the input view conversion unless
4300 one of the types is a fat pointer, which is handled by
4301 specialized code below which relies on exact type matching. */
4305 }
4308 }
4312 }
4314 /* Check for converting to a pointer to an unconstrained array. */
4318 /* If we are converting between two aggregate or vector types that are mere
4319 variants, just make a VIEW_CONVERT_EXPR. Likewise when we are converting
4320 to a vector type from its representative array type. */
4327 etype)))
4330 /* If we are converting between tagged types, try to upcast properly. */
4333 {
4341 }
4343 /* If we are converting from a smaller form of record type back to it, just
4344 make a VIEW_CONVERT_EXPR. But first pad the expression to have the same
4345 size on both sides. */
4348 {
4351 expr);
4353 }
4355 /* In all other cases of related types, make a NOP_EXPR. */
4360 {
4376 /* ... fall through ... */
4380 /* If we are converting an additive expression to an integer type
4381 with lower precision, be wary of the optimization that can be
4382 applied by convert_to_integer. There are 2 problematic cases:
4383 - if the first operand was originally of a biased type,
4384 because we could be recursively called to convert it
4385 to an intermediate type and thus rematerialize the
4386 additive operator endlessly,
4387 - if the expression contains a placeholder, because an
4388 intermediate conversion that changes the sign could
4389 be inserted and thus introduce an artificial overflow
4390 at compile time when the placeholder is substituted. */
4395 {
4402 }
4408 /* If converting between two thin pointers, adjust if needed to account
4409 for differing offsets from the base pointer, depending on whether
4410 there is a TYPE_UNCONSTRAINED_ARRAY attached to the record type. */
4412 {
4413 tree etype_pos
4417 tree type_pos
4429 }
4431 /* If converting fat pointer to normal or thin pointer, get the pointer
4432 to the array and then convert it. */
4434 expr
4444 {
4450 expr));
4452 }
4454 /* ... fall through ... */
4457 /* In these cases, assume the front-end has validated the conversion.
4458 If the conversion is valid, it will be a bit-wise conversion, so
4459 it can be viewed as an unchecked conversion. */
4463 /* This is a either a conversion between a tagged type and some
4464 subtype, which we have to mark as a UNION_TYPE because of
4465 overlapping fields or a conversion of an Unchecked_Union. */
4469 /* If the input is a VECTOR_TYPE, convert to the representative
4470 array type first. */
4472 {
4476 }
4478 /* If EXPR is a constrained array, take its address, convert it to a
4479 fat pointer, and then dereference it. Likewise if EXPR is a
4480 record containing both a template and a constrained array.
4481 Note that a record representing a justified modular type
4482 always represents a packed constrained array. */
4487 return
4488 build_unary_op
4494 /* Do something very similar for converting one unconstrained
4495 array to another. */
4497 return
4502 else
4510 }
4511 }
4513 /* Create an expression whose value is that of EXPR converted to the common
4514 index type, which is sizetype. EXPR is supposed to be in the base type
4515 of the GNAT index type. Calling it is equivalent to doing
4517 convert (sizetype, expr)
4519 but we try to distribute the type conversion with the knowledge that EXPR
4520 cannot overflow in its type. This is a best-effort approach and we fall
4521 back to the above expression as soon as difficulties are encountered.
4523 This is necessary to overcome issues that arise when the GNAT base index
4524 type and the GCC common index type (sizetype) don't have the same size,
4525 which is quite frequent on 64-bit architectures. In this case, and if
4526 the GNAT base index type is signed but the iteration type of the loop has
4527 been forced to unsigned, the loop scalar evolution engine cannot compute
4528 a simple evolution for the general induction variables associated with the
4529 array indices, because it will preserve the wrap-around semantics in the
4530 unsigned type of their "inner" part. As a result, many loop optimizations
4531 are blocked.
4533 The solution is to use a special (basic) induction variable that is at
4534 least as large as sizetype, and to express the aforementioned general
4535 induction variables in terms of this induction variable, eliminating
4536 the problematic intermediate truncation to the GNAT base index type.
4537 This is possible as long as the original expression doesn't overflow
4538 and if the middle-end hasn't introduced artificial overflows in the
4539 course of the various simplification it can make to the expression. */
4541 tree
4543 {
4547 /* If the type is unsigned, overflow is allowed so we cannot be sure that
4548 EXPR doesn't overflow. Keep it simple if optimization is disabled. */
4553 {
4555 /* The main effect of the function: replace a loop parameter with its
4556 associated special induction variable. */
4561 CASE_CONVERT:
4562 {
4564 /* Bail out as soon as we suspect some sort of type frobbing. */
4568 }
4570 /* ... fall through ... */
4594 }
4597 }
4598 \f
4599 /* Remove all conversions that are done in EXP. This includes converting
4600 from a padded type or to a justified modular type. If TRUE_ADDRESS
4601 is true, always return the address of the containing object even if
4602 the address is not bit-aligned. */
4604 tree
4606 {
4608 {
4613 return
4622 CASE_CONVERT:
4629 }
4632 }
4633 \f
4634 /* If EXP's type is an UNCONSTRAINED_ARRAY_TYPE, return an expression that
4635 refers to the underlying array. If it has TYPE_CONTAINS_TEMPLATE_P,
4636 likewise return an expression pointing to the underlying array. */
4638 tree
4640 {
4645 {
4648 {
4656 {
4657 tree op1
4660 NULL_TREE,
4663 tree op2
4666 NULL_TREE,
4673 }
4674 else
4675 {
4682 }
4683 }
4692 /* If this is a padded type and it contains a template, convert to the
4693 unpadded type first. */
4697 {
4700 }
4703 {
4709 /* If the array type is padded, convert to the unpadded type. */
4712 }
4717 }
4720 }
4721 \f
4722 /* Return true if EXPR is an expression that can be folded as an operand
4723 of a VIEW_CONVERT_EXPR. See ada-tree.h for a complete rationale. */
4725 static bool
4727 {
4730 /* The folder will fold NOP_EXPRs between integral types with the same
4731 precision (in the middle-end's sense). We cannot allow it if the
4732 types don't have the same precision in the Ada sense as well. */
4739 /* Defer to the folder for non-integral conversions. */
4743 /* Only fold conversions that preserve both precisions. */
4749 }
4751 /* Return an expression that does an unchecked conversion of EXPR to TYPE.
4752 If NOTRUNC_P is true, truncation operations should be suppressed.
4754 Special care is required with (source or target) integral types whose
4755 precision is not equal to their size, to make sure we fetch or assign
4756 the value bits whose location might depend on the endianness, e.g.
4758 Rmsize : constant := 8;
4759 subtype Int is Integer range 0 .. 2 ** Rmsize - 1;
4761 type Bit_Array is array (1 .. Rmsize) of Boolean;
4762 pragma Pack (Bit_Array);
4764 function To_Bit_Array is new Unchecked_Conversion (Int, Bit_Array);
4766 Value : Int := 2#1000_0001#;
4767 Vbits : Bit_Array := To_Bit_Array (Value);
4769 we expect the 8 bits at Vbits'Address to always contain Value, while
4770 their original location depends on the endianness, at Value'Address
4771 on a little-endian architecture but not on a big-endian one. */
4773 tree
4775 {
4779 tree tem;
4782 /* If the expression is already of the right type, we are done. */
4786 /* If both types types are integral just do a normal conversion.
4787 Likewise for a conversion to an unconstrained array. */
4795 {
4797 {
4802 }
4805 {
4811 }
4812 else
4814 }
4816 /* If we are converting to an integral type whose precision is not equal
4817 to its size, first unchecked convert to a record type that contains an
4818 field of the given precision. Then extract the field. */
4823 {
4830 else
4842 }
4844 /* Similarly if we are converting from an integral type whose precision is
4845 not equal to its size, first copy into a field of the given precision
4846 and unchecked convert the record type. */
4851 {
4860 else
4873 }
4875 /* If we are converting from a scalar type to a type with a different size,
4876 we need to pad to have the same size on both sides.
4878 ??? We cannot do it unconditionally because unchecked conversions are
4879 used liberally by the front-end to implement polymorphism, e.g. in:
4881 S191s : constant ada__tags__addr_ptr := ada__tags__addr_ptr!(S190s);
4882 return p___size__4 (p__object!(S191s.all));
4884 so we skip all expressions that are references. */
4889 {
4891 {
4894 expr);
4896 }
4897 else
4898 {
4904 }
4905 }
4907 /* We have a special case when we are converting between two unconstrained
4908 array types. In that case, take the address, convert the fat pointer
4909 types, and dereference. */
4914 expr)));
4916 /* Another special case is when we are converting to a vector type from its
4917 representative array type; this a regular conversion. */
4921 etype))
4924 /* And, if the array type is not the representative, we try to build an
4925 intermediate vector type of which the array type is the representative
4926 and to do the unchecked conversion between the vector types, in order
4927 to enable further simplifications in the middle-end. */
4931 {
4934 }
4936 /* If we are converting a CONSTRUCTOR to a more aligned RECORD_TYPE, bump
4937 the alignment of the CONSTRUCTOR to speed up the copy operation. */
4941 {
4944 expr);
4946 }
4948 /* Otherwise, just build a VIEW_CONVERT_EXPR of the expression. */
4949 else
4950 {
4956 else
4958 }
4960 /* If the result is an integral type whose precision is not equal to its
4961 size, sign- or zero-extend the result. We need not do this if the input
4962 is an integral type of the same precision and signedness or if the output
4963 is a biased type or if both the input and output are unsigned. */
4976 {
4977 tree base_type
4979 tree shift_expr
4982 bitsize_int
4985 expr
4990 shift_expr),
4991 shift_expr));
4992 }
4994 /* An unchecked conversion should never raise Constraint_Error. The code
4995 below assumes that GCC's conversion routines overflow the same way that
4996 the underlying hardware does. This is probably true. In the rare case
4997 when it is false, we can rely on the fact that such conversions are
4998 erroneous anyway. */
5002 /* If the sizes of the types differ and this is an VIEW_CONVERT_EXPR,
5003 show no longer constant. */
5006 OEP_ONLY_CONST))
5010 }
5011 \f
5012 /* Return the appropriate GCC tree code for the specified GNAT_TYPE,
5013 the latter being a record type as predicated by Is_Record_Type. */
5015 enum tree_code
5017 {
5020 /* Return UNION_TYPE if it's an Unchecked_Union whose non-discriminant
5021 fields are all in the variant part. Otherwise, return RECORD_TYPE. */
5026 component_list
5036 }
5038 /* Return true if GNAT_TYPE is a "double" floating-point type, i.e. whose
5039 size is equal to 64 bits, or an array of such a type. Set ALIGN_CLAUSE
5040 according to the presence of an alignment clause on the type or, if it
5041 is an array, on the component type. */
5043 bool
5045 {
5051 {
5055 }
5064 }
5066 /* Return true if GNAT_TYPE is a "double" or larger scalar type, i.e. whose
5067 size is greater or equal to 64 bits, or an array of such a type. Set
5068 ALIGN_CLAUSE according to the presence of an alignment clause on the
5069 type or, if it is an array, on the component type. */
5071 bool
5073 {
5079 {
5083 }
5092 }
5094 /* Return true if GNU_TYPE is suitable as the type of a non-aliased
5095 component of an aggregate type. */
5097 bool
5099 {
5100 /* If the type is passed by reference, we may have pointers to the
5101 component so it cannot be made non-aliased. */
5105 /* We used to say that any component of aggregate type is aliased
5106 because the front-end may take 'Reference of it. The front-end
5107 has been enhanced in the meantime so as to use a renaming instead
5108 in most cases, but the back-end can probably take the address of
5109 such a component too so we go for the conservative stance.
5111 For instance, we might need the address of any array type, even
5112 if normally passed by copy, to construct a fat pointer if the
5113 component is used as an actual for an unconstrained formal.
5115 Likewise for record types: even if a specific record subtype is
5116 passed by copy, the parent type might be passed by ref (e.g. if
5117 it's of variable size) and we might take the address of a child
5118 component to pass to a parent formal. We have no way to check
5119 for such conditions here. */
5124 }
5126 /* Return true if TYPE is a smaller form of ORIG_TYPE. */
5128 bool
5130 {
5133 /* We're not interested in variants here. */
5137 /* Like a variant, a packable version keeps the original TYPE_NAME. */
5148 }
5150 /* Perform final processing on global variables. */
5154 void
5156 {
5158 tree iter;
5160 /* If we have declared types as used at the global level, insert them in
5161 the global hash table. We use a dummy variable for this purpose. */
5163 {
5168 dummy_global
5170 void_type_node);
5178 {
5181 }
5182 }
5184 /* Output debug information for all global type declarations first. This
5185 ensures that global types whose compilation hasn't been finalized yet,
5186 for example pointers to Taft amendment types, have their compilation
5187 finalized in the right context. */
5192 /* Proceed to optimize and emit assembly. */
5195 /* After cgraph has had a chance to emit everything that's going to
5196 be emitted, output debug information for the rest of globals. */
5198 {
5204 }
5205 }
5207 /* ************************************************************************
5208 * * GCC builtins support *
5209 * ************************************************************************ */
5211 /* The general scheme is fairly simple:
5213 For each builtin function/type to be declared, gnat_install_builtins calls
5214 internal facilities which eventually get to gnat_push_decl, which in turn
5215 tracks the so declared builtin function decls in the 'builtin_decls' global
5216 datastructure. When an Intrinsic subprogram declaration is processed, we
5217 search this global datastructure to retrieve the associated BUILT_IN DECL
5218 node. */
5220 /* Search the chain of currently available builtin declarations for a node
5221 corresponding to function NAME (an IDENTIFIER_NODE). Return the first node
5222 found, if any, or NULL_TREE otherwise. */
5223 tree
5225 {
5227 tree decl;
5234 }
5236 /* The code below eventually exposes gnat_install_builtins, which declares
5237 the builtin types and functions we might need, either internally or as
5238 user accessible facilities.
5240 ??? This is a first implementation shot, still in rough shape. It is
5241 heavily inspired from the "C" family implementation, with chunks copied
5242 verbatim from there.
5244 Two obvious TODO candidates are
5245 o Use a more efficient name/decl mapping scheme
5246 o Devise a middle-end infrastructure to avoid having to copy
5247 pieces between front-ends. */
5249 /* ----------------------------------------------------------------------- *
5250 * BUILTIN ELEMENTARY TYPES *
5251 * ----------------------------------------------------------------------- */
5253 /* Standard data types to be used in builtin argument declarations. */
5255 enum c_tree_index
5256 {
5258 CTI_STRING_TYPE,
5259 CTI_CONST_STRING_TYPE,
5261 CTI_MAX
5262 };
5266 #define signed_size_type_node c_global_trees[CTI_SIGNED_SIZE_TYPE]
5267 #define string_type_node c_global_trees[CTI_STRING_TYPE]
5268 #define const_string_type_node c_global_trees[CTI_CONST_STRING_TYPE]
5270 /* ??? In addition some attribute handlers, we currently don't support a
5271 (small) number of builtin-types, which in turns inhibits support for a
5272 number of builtin functions. */
5273 #define wint_type_node void_type_node
5274 #define intmax_type_node void_type_node
5275 #define uintmax_type_node void_type_node
5277 /* Build the void_list_node (void_type_node having been created). */
5279 static tree
5281 {
5284 }
5286 /* Used to help initialize the builtin-types.def table. When a type of
5287 the correct size doesn't exist, use error_mark_node instead of NULL.
5288 The later results in segfaults even when a decl using the type doesn't
5289 get invoked. */
5291 static tree
5293 {
5296 }
5298 /* Build/push the elementary type decls that builtin functions/types
5299 will need. */
5301 static void
5303 {
5309 const_string_type_node
5312 }
5314 /* ----------------------------------------------------------------------- *
5315 * BUILTIN FUNCTION TYPES *
5316 * ----------------------------------------------------------------------- */
5318 /* Now, builtin function types per se. */
5320 enum c_builtin_type
5321 {
5322 #define DEF_PRIMITIVE_TYPE(NAME, VALUE) NAME,
5323 #define DEF_FUNCTION_TYPE_0(NAME, RETURN) NAME,
5324 #define DEF_FUNCTION_TYPE_1(NAME, RETURN, ARG1) NAME,
5325 #define DEF_FUNCTION_TYPE_2(NAME, RETURN, ARG1, ARG2) NAME,
5326 #define DEF_FUNCTION_TYPE_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
5327 #define DEF_FUNCTION_TYPE_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
5328 #define DEF_FUNCTION_TYPE_5(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) NAME,
5329 #define DEF_FUNCTION_TYPE_6(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
5330 ARG6) NAME,
5331 #define DEF_FUNCTION_TYPE_7(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
5332 ARG6, ARG7) NAME,
5333 #define DEF_FUNCTION_TYPE_8(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
5334 ARG6, ARG7, ARG8) NAME,
5335 #define DEF_FUNCTION_TYPE_VAR_0(NAME, RETURN) NAME,
5336 #define DEF_FUNCTION_TYPE_VAR_1(NAME, RETURN, ARG1) NAME,
5337 #define DEF_FUNCTION_TYPE_VAR_2(NAME, RETURN, ARG1, ARG2) NAME,
5338 #define DEF_FUNCTION_TYPE_VAR_3(NAME, RETURN, ARG1, ARG2, ARG3) NAME,
5339 #define DEF_FUNCTION_TYPE_VAR_4(NAME, RETURN, ARG1, ARG2, ARG3, ARG4) NAME,
5340 #define DEF_FUNCTION_TYPE_VAR_5(NAME, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
5341 NAME,
5342 #define DEF_POINTER_TYPE(NAME, TYPE) NAME,
5344 #undef DEF_PRIMITIVE_TYPE
5345 #undef DEF_FUNCTION_TYPE_0
5346 #undef DEF_FUNCTION_TYPE_1
5347 #undef DEF_FUNCTION_TYPE_2
5348 #undef DEF_FUNCTION_TYPE_3
5349 #undef DEF_FUNCTION_TYPE_4
5350 #undef DEF_FUNCTION_TYPE_5
5351 #undef DEF_FUNCTION_TYPE_6
5352 #undef DEF_FUNCTION_TYPE_7
5353 #undef DEF_FUNCTION_TYPE_8
5354 #undef DEF_FUNCTION_TYPE_VAR_0
5355 #undef DEF_FUNCTION_TYPE_VAR_1
5356 #undef DEF_FUNCTION_TYPE_VAR_2
5357 #undef DEF_FUNCTION_TYPE_VAR_3
5358 #undef DEF_FUNCTION_TYPE_VAR_4
5359 #undef DEF_FUNCTION_TYPE_VAR_5
5360 #undef DEF_POINTER_TYPE
5361 BT_LAST
5362 };
5366 /* A temporary array used in communication with def_fn_type. */
5369 /* A helper function for install_builtin_types. Build function type
5370 for DEF with return type RET and N arguments. If VAR is true, then the
5371 function should be variadic after those N arguments.
5373 Takes special care not to ICE if any of the types involved are
5374 error_mark_node, which indicates that said type is not in fact available
5375 (see builtin_type_for_size). In which case the function type as a whole
5376 should be error_mark_node. */
5378 static void
5380 {
5381 tree t;
5388 {
5394 }
5401 else
5404 egress:
5407 }
5409 /* Build the builtin function types and install them in the builtin_types
5410 array for later use in builtin function decls. */
5412 static void
5414 {
5415 tree va_list_ref_type_node;
5416 tree va_list_arg_type_node;
5419 {
5422 }
5423 else
5424 {
5427 }
5429 #define DEF_PRIMITIVE_TYPE(ENUM, VALUE) \
5430 builtin_types[ENUM] = VALUE;
5431 #define DEF_FUNCTION_TYPE_0(ENUM, RETURN) \
5432 def_fn_type (ENUM, RETURN, 0, 0);
5433 #define DEF_FUNCTION_TYPE_1(ENUM, RETURN, ARG1) \
5434 def_fn_type (ENUM, RETURN, 0, 1, ARG1);
5435 #define DEF_FUNCTION_TYPE_2(ENUM, RETURN, ARG1, ARG2) \
5436 def_fn_type (ENUM, RETURN, 0, 2, ARG1, ARG2);
5437 #define DEF_FUNCTION_TYPE_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
5438 def_fn_type (ENUM, RETURN, 0, 3, ARG1, ARG2, ARG3);
5439 #define DEF_FUNCTION_TYPE_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
5440 def_fn_type (ENUM, RETURN, 0, 4, ARG1, ARG2, ARG3, ARG4);
5441 #define DEF_FUNCTION_TYPE_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
5442 def_fn_type (ENUM, RETURN, 0, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
5443 #define DEF_FUNCTION_TYPE_6(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
5444 ARG6) \
5445 def_fn_type (ENUM, RETURN, 0, 6, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6);
5446 #define DEF_FUNCTION_TYPE_7(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
5447 ARG6, ARG7) \
5448 def_fn_type (ENUM, RETURN, 0, 7, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, ARG7);
5449 #define DEF_FUNCTION_TYPE_8(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5, \
5450 ARG6, ARG7, ARG8) \
5451 def_fn_type (ENUM, RETURN, 0, 8, ARG1, ARG2, ARG3, ARG4, ARG5, ARG6, \
5452 ARG7, ARG8);
5453 #define DEF_FUNCTION_TYPE_VAR_0(ENUM, RETURN) \
5454 def_fn_type (ENUM, RETURN, 1, 0);
5455 #define DEF_FUNCTION_TYPE_VAR_1(ENUM, RETURN, ARG1) \
5456 def_fn_type (ENUM, RETURN, 1, 1, ARG1);
5457 #define DEF_FUNCTION_TYPE_VAR_2(ENUM, RETURN, ARG1, ARG2) \
5458 def_fn_type (ENUM, RETURN, 1, 2, ARG1, ARG2);
5459 #define DEF_FUNCTION_TYPE_VAR_3(ENUM, RETURN, ARG1, ARG2, ARG3) \
5460 def_fn_type (ENUM, RETURN, 1, 3, ARG1, ARG2, ARG3);
5461 #define DEF_FUNCTION_TYPE_VAR_4(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4) \
5462 def_fn_type (ENUM, RETURN, 1, 4, ARG1, ARG2, ARG3, ARG4);
5463 #define DEF_FUNCTION_TYPE_VAR_5(ENUM, RETURN, ARG1, ARG2, ARG3, ARG4, ARG5) \
5464 def_fn_type (ENUM, RETURN, 1, 5, ARG1, ARG2, ARG3, ARG4, ARG5);
5465 #define DEF_POINTER_TYPE(ENUM, TYPE) \
5466 builtin_types[(int) ENUM] = build_pointer_type (builtin_types[(int) TYPE]);
5470 #undef DEF_PRIMITIVE_TYPE
5471 #undef DEF_FUNCTION_TYPE_0
5472 #undef DEF_FUNCTION_TYPE_1
5473 #undef DEF_FUNCTION_TYPE_2
5474 #undef DEF_FUNCTION_TYPE_3
5475 #undef DEF_FUNCTION_TYPE_4
5476 #undef DEF_FUNCTION_TYPE_5
5477 #undef DEF_FUNCTION_TYPE_6
5478 #undef DEF_FUNCTION_TYPE_7
5479 #undef DEF_FUNCTION_TYPE_8
5480 #undef DEF_FUNCTION_TYPE_VAR_0
5481 #undef DEF_FUNCTION_TYPE_VAR_1
5482 #undef DEF_FUNCTION_TYPE_VAR_2
5483 #undef DEF_FUNCTION_TYPE_VAR_3
5484 #undef DEF_FUNCTION_TYPE_VAR_4
5485 #undef DEF_FUNCTION_TYPE_VAR_5
5486 #undef DEF_POINTER_TYPE
5488 }
5490 /* ----------------------------------------------------------------------- *
5491 * BUILTIN ATTRIBUTES *
5492 * ----------------------------------------------------------------------- */
5494 enum built_in_attribute
5495 {
5496 #define DEF_ATTR_NULL_TREE(ENUM) ENUM,
5497 #define DEF_ATTR_INT(ENUM, VALUE) ENUM,
5498 #define DEF_ATTR_STRING(ENUM, VALUE) ENUM,
5499 #define DEF_ATTR_IDENT(ENUM, STRING) ENUM,
5500 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) ENUM,
5502 #undef DEF_ATTR_NULL_TREE
5503 #undef DEF_ATTR_INT
5504 #undef DEF_ATTR_STRING
5505 #undef DEF_ATTR_IDENT
5506 #undef DEF_ATTR_TREE_LIST
5507 ATTR_LAST
5508 };
5512 static void
5514 {
5515 /* Fill in the built_in_attributes array. */
5516 #define DEF_ATTR_NULL_TREE(ENUM) \
5517 built_in_attributes[(int) ENUM] = NULL_TREE;
5518 #define DEF_ATTR_INT(ENUM, VALUE) \
5519 built_in_attributes[(int) ENUM] = build_int_cst (NULL_TREE, VALUE);
5520 #define DEF_ATTR_STRING(ENUM, VALUE) \
5521 built_in_attributes[(int) ENUM] = build_string (strlen (VALUE), VALUE);
5522 #define DEF_ATTR_IDENT(ENUM, STRING) \
5523 built_in_attributes[(int) ENUM] = get_identifier (STRING);
5524 #define DEF_ATTR_TREE_LIST(ENUM, PURPOSE, VALUE, CHAIN) \
5525 built_in_attributes[(int) ENUM] \
5526 = tree_cons (built_in_attributes[(int) PURPOSE], \
5527 built_in_attributes[(int) VALUE], \
5528 built_in_attributes[(int) CHAIN]);
5530 #undef DEF_ATTR_NULL_TREE
5531 #undef DEF_ATTR_INT
5532 #undef DEF_ATTR_STRING
5533 #undef DEF_ATTR_IDENT
5534 #undef DEF_ATTR_TREE_LIST
5535 }
5537 /* Handle a "const" attribute; arguments as in
5538 struct attribute_spec.handler. */
5540 static tree
5544 {
5547 else
5551 }
5553 /* Handle a "nothrow" attribute; arguments as in
5554 struct attribute_spec.handler. */
5556 static tree
5560 {
5563 else
5567 }
5569 /* Handle a "pure" attribute; arguments as in
5570 struct attribute_spec.handler. */
5572 static tree
5575 {
5578 /* ??? TODO: Support types. */
5579 else
5580 {
5584 }
5587 }
5589 /* Handle a "no vops" attribute; arguments as in
5590 struct attribute_spec.handler. */
5592 static tree
5596 {
5600 }
5602 /* Helper for nonnull attribute handling; fetch the operand number
5603 from the attribute argument list. */
5605 static bool
5607 {
5608 /* Verify the arg number is a constant. */
5614 }
5616 /* Handle the "nonnull" attribute. */
5617 static tree
5621 {
5625 /* If no arguments are specified, all pointer arguments should be
5626 non-null. Verify a full prototype is given so that the arguments
5627 will have the correct types when we actually check them later. */
5629 {
5631 {
5634 }
5636 }
5638 /* Argument list specified. Verify that each argument number references
5639 a pointer argument. */
5641 {
5645 {
5650 }
5653 {
5654 function_args_iterator iter;
5655 tree argument;
5659 {
5663 }
5667 {
5673 }
5676 {
5682 }
5683 }
5684 }
5687 }
5689 /* Handle a "sentinel" attribute. */
5691 static tree
5694 {
5696 {
5701 }
5702 else
5703 {
5705 {
5710 }
5711 }
5714 {
5718 {
5721 }
5722 else
5723 {
5725 {
5728 }
5729 }
5730 }
5733 }
5735 /* Handle a "noreturn" attribute; arguments as in
5736 struct attribute_spec.handler. */
5738 static tree
5741 {
5744 /* See FIXME comment in c_common_attribute_table. */
5750 = build_pointer_type
5753 else
5754 {
5758 }
5761 }
5763 /* Handle a "leaf" attribute; arguments as in
5764 struct attribute_spec.handler. */
5766 static tree
5769 {
5771 {
5774 }
5776 {
5779 }
5782 }
5784 /* Handle a "always_inline" attribute; arguments as in
5785 struct attribute_spec.handler. */
5787 static tree
5790 {
5792 {
5793 /* Set the attribute and mark it for disregarding inline limits. */
5795 }
5796 else
5797 {
5800 }
5803 }
5805 /* Handle a "malloc" attribute; arguments as in
5806 struct attribute_spec.handler. */
5808 static tree
5811 {
5815 else
5816 {
5820 }
5823 }
5825 /* Fake handler for attributes we don't properly support. */
5827 tree
5833 {
5835 }
5837 /* Handle a "type_generic" attribute. */
5839 static tree
5843 {
5844 /* Ensure we have a function type. */
5847 /* Ensure we have a variadic function. */
5851 }
5853 /* Handle a "vector_size" attribute; arguments as in
5854 struct attribute_spec.handler. */
5856 static tree
5859 {
5861 tree vector_type;
5865 /* We need to provide for vector pointers, vector arrays, and
5866 functions returning vectors. For example:
5868 __attribute__((vector_size(16))) short *foo;
5870 In this case, the mode is SI, but the type being modified is
5871 HI, so we need to look further. */
5881 /* Build back pointers if needed. */
5885 }
5887 /* Handle a "vector_type" attribute; arguments as in
5888 struct attribute_spec.handler. */
5890 static tree
5893 {
5895 tree vector_type;
5900 {
5904 }
5914 }
5916 /* ----------------------------------------------------------------------- *
5917 * BUILTIN FUNCTIONS *
5918 * ----------------------------------------------------------------------- */
5920 /* Worker for DEF_BUILTIN. Possibly define a builtin function with one or two
5921 names. Does not declare a non-__builtin_ function if flag_no_builtin, or
5922 if nonansi_p and flag_no_nonansi_builtin. */
5924 static void
5932 {
5933 tree decl;
5936 /* Preserve an already installed decl. It most likely was setup in advance
5937 (e.g. as part of the internal builtins) for specific reasons. */
5948 fnattrs);
5950 /* ??? This is normally further controlled by command-line options
5951 like -fno-builtin, but we don't have them for Ada. */
5956 }
5962 /* Install what the common builtins.def offers. */
5964 static void
5966 {
5967 #define DEF_BUILTIN(ENUM, NAME, CLASS, TYPE, LIBTYPE, BOTH_P, FALLBACK_P, \
5968 NONANSI_P, ATTRS, IMPLICIT, COND) \
5969 if (NAME && COND) \
5970 def_builtin_1 (ENUM, NAME, CLASS, \
5971 builtin_types[(int) TYPE], \
5972 builtin_types[(int) LIBTYPE], \
5973 BOTH_P, FALLBACK_P, NONANSI_P, \
5974 built_in_attributes[(int) ATTRS], IMPLICIT);
5976 #undef DEF_BUILTIN
5977 }
5979 /* ----------------------------------------------------------------------- *
5980 * BUILTIN FUNCTIONS *
5981 * ----------------------------------------------------------------------- */
5983 /* Install the builtin functions we might need. */
5985 void
5987 {
5992 /* Install builtins used by generic middle-end pieces first. Some of these
5993 know about internal specificities and control attributes accordingly, for
5994 instance __builtin_alloca vs no-throw and -fstack-check. We will ignore
5995 the generic definition from builtins.def. */
5998 /* Now, install the target specific builtins, such as the AltiVec family on
5999 ppc, and the common set as exposed by builtins.def. */
6002 }