| blob | 9d933b740d0785b7a40cbf0caa04e26f270a4737 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2008, 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 ****************************************************************************/
56 #ifndef MAX_FIXED_MODE_SIZE
57 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
58 #endif
60 /* Convention_Stdcall should be processed in a specific way on Windows targets
61 only. The macro below is a helper to avoid having to check for a Windows
62 specific attribute throughout this unit. */
64 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
65 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
66 #else
67 #define Has_Stdcall_Convention(E) (0)
68 #endif
70 struct incomplete
71 {
73 tree old_type;
74 Entity_Id full_type;
75 };
77 /* These variables are used to defer recursively expanding incomplete types
78 while we are processing an array, a record or a subprogram type. */
82 /* This variable is used to delay expanding From_With_Type types until the
83 end of the spec. */
86 /* These variables are used to defer finalizing types. The element of the
87 list is the TYPE_DECL associated with the type. */
91 /* A hash table used to cache the result of annotate_value. */
125 /* Given GNAT_ENTITY, an entity in the incoming GNAT tree, return a
126 GCC type corresponding to that entity. GNAT_ENTITY is assumed to
127 refer to an Ada type. */
129 tree
131 {
132 tree gnu_decl;
134 /* The back end never attempts to annotate generic types */
138 /* Convert the ada entity type into a GCC TYPE_DECL node. */
142 }
143 \f
144 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
145 entity, this routine returns the equivalent GCC tree for that entity
146 (an ..._DECL node) and associates the ..._DECL node with the input GNAT
147 defining identifier.
149 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
150 initial value (in GCC tree form). This is optional for variables.
151 For renamed entities, GNU_EXPR gives the object being renamed.
153 DEFINITION is nonzero if this call is intended for a definition. This is
154 used for separate compilation where it necessary to know whether an
155 external declaration or a definition should be created if the GCC equivalent
156 was not created previously. The value of 1 is normally used for a nonzero
157 DEFINITION, but a value of 2 is used in special circumstances, defined in
158 the code. */
160 tree
162 {
164 tree gnu_entity_id;
166 /* Contains the gnu XXXX_DECL tree node which is equivalent to the input
167 GNAT tree. This node will be associated with the GNAT node by calling
168 the save_gnu_tree routine at the end of the `switch' statement. */
170 /* true if we have already saved gnu_decl as a gnat association. */
172 /* Nonzero if we incremented defer_incomplete_level. */
174 /* Nonzero if we incremented force_global. */
176 /* Nonzero if we should check to see if elaborated during processing. */
178 /* Nonzero if we made GNU_DECL and its type here. */
184 Entity_Id gnat_temp;
185 unsigned int esize
195 bool imported_p
199 /* Since a use of an Itype is a definition, process it as such if it
200 is not in a with'ed unit. */
205 {
206 /* Ensure that we are in a subprogram mentioned in the Scope
207 chain of this entity, our current scope is global,
208 or that we encountered a task or entry (where we can't currently
209 accurately check scoping). */
212 {
215 }
219 {
224 gnat_temp
236 && (current_function_decl
238 {
241 }
242 }
244 /* This abort means the entity "gnat_entity" has an incorrect scope,
245 i.e. that its scope does not correspond to the subprogram in which
246 it is declared */
248 }
250 /* If this is entity 0, something went badly wrong. */
253 /* If we've already processed this entity, return what we got last time.
254 If we are defining the node, we should not have already processed it.
255 In that case, we will abort below when we try to save a new GCC tree for
256 this object. We also need to handle the case of getting a dummy type
257 when a Full_View exists. */
261 {
268 {
274 }
277 }
279 /* If this is a numeric or enumeral type, or an access type, a nonzero
280 Esize must be specified unless it was specified by the programmer. */
289 /* Likewise, RM_Size must be specified for all discrete and fixed-point
290 types. */
294 /* Get the name of the entity and set up the line number and filename of
295 the original definition for use in any decl we make. */
299 /* If we get here, it means we have not yet done anything with this
300 entity. If we are not defining it here, it must be external,
301 otherwise we should have defined it already. */
308 /* For cases when we are not defining (i.e., we are referencing from
309 another compilation unit) Public entities, show we are at global level
310 for the purpose of computing scopes. Don't do this for components or
311 discriminants since the relevant test is whether or not the record is
312 being defined. But do this for Imported functions or procedures in
313 all cases. */
321 /* Handle any attributes directly attached to the entity. */
325 /* Machine_Attributes on types are expected to be propagated to subtypes.
326 The corresponding Gigi_Rep_Items are only attached to the first subtype
327 though, so we handle the propagation here. */
334 {
336 /* If this is a use of a deferred constant, get its full
337 declaration. */
339 {
344 }
346 /* If we have an external constant that we are not defining, get the
347 expression that is was defined to represent. We may throw that
348 expression away later if it is not a constant. Do not retrieve the
349 expression if it is an aggregate or allocator, because in complex
350 instantiation contexts it may not be expanded */
360 /* Ignore deferred constant definitions; they are processed fully in the
361 front-end. For deferred constant references get the full definition.
362 On the other hand, constants that are renamings are handled like
363 variable renamings. If No_Initialization is set, this is not a
364 deferred constant but a constant whose value is built manually. */
368 {
372 }
375 {
380 }
385 /* We used to special case VMS exceptions here to directly map them to
386 their associated condition code. Since this code had to be masked
387 dynamically to strip off the severity bits, this caused trouble in
388 the GCC/ZCX case because the "type" pointers we store in the tables
389 have to be static. We now don't special case here anymore, and let
390 the regular processing take place, which leaves us with a regular
391 exception data object for VMS exceptions too. The condition code
392 mapping is taken care of by the front end and the bitmasking by the
393 runtime library. */
398 {
399 /* The GNAT record where the component was defined. */
402 /* If the variable is an inherited record component (in the case of
403 extended record types), just return the inherited entity, which
404 must be a FIELD_DECL. Likewise for discriminants.
405 For discriminants of untagged records which have explicit
406 stored discriminants, return the entity for the corresponding
407 stored discriminant. Also use Original_Record_Component
408 if the record has a private extension. */
412 {
413 gnu_decl
418 }
420 /* If the enclosing record has explicit stored discriminants,
421 then it is an untagged record. If the Corresponding_Discriminant
422 is not empty then this must be a renamed discriminant and its
423 Original_Record_Component must point to the corresponding explicit
424 stored discriminant (i.e., we should have taken the previous
425 branch). */
429 {
430 /* A tagged record has no explicit stored discriminants. */
434 gnu_decl
439 }
443 {
448 }
450 /* If the enclosing record has explicit stored discriminants,
451 then it is an untagged record. If the Corresponding_Discriminant
452 is not empty then this must be a renamed discriminant and its
453 Original_Record_Component must point to the corresponding explicit
454 stored discriminant (i.e., we should have taken the first
455 branch). */
462 /* Otherwise, if we are not defining this and we have no GCC type
463 for the containing record, make one for it. Then we should
464 have made our own equivalent. */
466 {
467 /* ??? If this is in a record whose scope is a protected
468 type and we have an Original_Record_Component, use it.
469 This is a workaround for major problems in protected type
470 handling. */
477 {
478 gnu_decl
484 }
490 }
492 else
493 /* Here we have no GCC type and this is a reference rather than a
494 definition. This should never happen. Most likely the cause is a
495 reference before declaration in the gnat tree for gnat_entity. */
497 }
503 /* Simple variables, loop variables, Out parameters, and exceptions. */
504 object:
505 {
507 bool const_flag
519 tree gnu_object_size;
522 {
526 else
528 }
530 /* Get the type after elaborating the renamed object. */
533 /* For a debug renaming declaration, build a pure debug entity. */
535 {
536 rtx addr;
538 /* The (MEM (CONST (0))) pattern is prescribed by STABS. */
541 else
546 }
548 /* If this is a loop variable, its type should be the base type.
549 This is because the code for processing a loop determines whether
550 a normal loop end test can be done by comparing the bounds of the
551 loop against those of the base type, which is presumed to be the
552 size used for computation. But this is not correct when the size
553 of the subtype is smaller than the type. */
557 /* Reject non-renamed objects whose types are unconstrained arrays or
558 any object whose type is a dummy type or VOID_TYPE. */
564 {
567 force_global--;
569 }
571 /* If an alignment is specified, use it if valid. Note that
572 exceptions are objects but don't have alignments. We must do this
573 before we validate the size, since the alignment can affect the
574 size. */
576 {
582 }
584 /* If we are defining the object, see if it has a Size value and
585 validate it if so. If we are not defining the object and a Size
586 clause applies, simply retrieve the value. We don't want to ignore
587 the clause and it is expected to have been validated already. Then
588 get the new type, if any. */
597 {
598 gnu_type
604 }
606 /* If this object has self-referential size, it must be a record with
607 a default value. We are supposed to allocate an object of the
608 maximum size in this case unless it is a constant with an
609 initializing expression, in which case we can get the size from
610 that. Note that the resulting size may still be a variable, so
611 this may end up with an indirect allocation. */
614 {
616 {
619 {
620 /* If the initializing expression is itself a constant,
621 despite having a nominal type with self-referential
622 size, we can get the size directly from it. */
625 == RECORD_TYPE
626 && TYPE_IS_PADDING_P
630 || DECL_READONLY_ONCE_ELAB
633 else
634 gnu_size
636 }
637 else
639 }
640 /* We may have no GNU_EXPR because No_Initialization is
641 set even though there's an Expression. */
646 gnu_size
648 (Etype
650 else
651 {
654 }
655 }
657 /* If the size is zero bytes, make it one byte since some linkers have
658 trouble with zero-sized objects. If the object will have a
659 template, that will make it nonzero so don't bother. Also avoid
660 doing that for an object renaming or an object with an address
661 clause, as we would lose useful information on the view size
662 (e.g. for null array slices) and we are not allocating the object
663 here anyway. */
676 /* If this is an object with no specified size and alignment, and
677 if either it is atomic or we are not optimizing alignment for
678 space and it is composite and not an exception, an Out parameter
679 or a reference to another object, and the size of its type is a
680 constant, set the alignment to the smallest one which is not
681 smaller than the size, with an appropriate cap. */
689 && !imported_p
693 {
694 /* No point in jumping through all the hoops needed in order
695 to support BIGGEST_ALIGNMENT if we don't really have to. */
697 ? BIGGEST_ALIGNMENT
703 else
706 /* But make sure not to under-align the object. */
710 /* And honor the minimum valid atomic alignment, if any. */
711 #ifdef MINIMUM_ATOMIC_ALIGNMENT
714 #endif
715 }
717 /* If the object is set to have atomic components, find the component
718 type and validate it.
720 ??? Note that we ignore Has_Volatile_Components on objects; it's
721 not at all clear what to do in that case. */
724 {
733 }
735 /* Now check if the type of the object allows atomic access. Note
736 that we must test the type, even if this object has size and
737 alignment to allow such access, because we will be going
738 inside the padded record to assign to the object. We could fix
739 this by always copying via an intermediate value, but it's not
740 clear it's worth the effort. */
744 /* If this is an aliased object with an unconstrained nominal subtype,
745 make a type that includes the template. */
749 {
750 tree gnu_fat
753 gnu_type
757 }
759 #ifdef MINIMUM_ATOMIC_ALIGNMENT
760 /* If the size is a constant and no alignment is specified, force
761 the alignment to be the minimum valid atomic alignment. The
762 restriction on constant size avoids problems with variable-size
763 temporaries; if the size is variable, there's no issue with
764 atomic access. Also don't do this for a constant, since it isn't
765 necessary and can interfere with constant replacement. Finally,
766 do not do it for Out parameters since that creates an
767 size inconsistency with In parameters. */
776 #endif
778 /* Make a new type with the desired size and alignment, if needed.
779 But do not take into account alignment promotions to compute the
780 size of the object. */
787 /* Make a volatile version of this object's type if we are to make
788 the object volatile. We also interpret 13.3(19) conservatively
789 and disallow any optimizations for an object covered by it. */
792 /* Exclude exported constants created by the compiler,
793 which should boil down to static dispatch tables and
794 make it possible to put them in read-only memory. */
803 /* If this is a renaming, avoid as much as possible to create a new
804 object. However, in several cases, creating it is required.
805 This processing needs to be applied to the raw expression so
806 as to make it more likely to rename the underlying object. */
808 {
811 /* If the renamed object had padding, strip off the reference
812 to the inner object and reset our type. */
815 == RECORD_TYPE
817 /* Strip useless conversions around the object. */
819 {
822 }
824 /* Case 1: If this is a constant renaming stemming from a function
825 call, treat it as a normal object whose initial value is what
826 is being renamed. RM 3.3 says that the result of evaluating a
827 function call is a constant object. As a consequence, it can
828 be the inner object of a constant renaming. In this case, the
829 renaming must be fully instantiated, i.e. it cannot be a mere
830 reference to (part of) an existing object. */
832 {
838 }
840 /* Otherwise, see if we can proceed with a stabilized version of
841 the renamed entity or if we need to make a new object. */
843 {
847 /* Case 2: If the renaming entity need not be materialized and
848 the renamed expression is something we can stabilize, use
849 that for the renaming. At the global level, we can only do
850 this if we know no SAVE_EXPRs need be made, because the
851 expression we return might be used in arbitrary conditional
852 branches so we must force the SAVE_EXPRs evaluation
853 immediately and this requires a function context. */
858 {
859 maybe_stable_expr
863 {
865 /* ??? No DECL_EXPR is created so we need to mark
866 the expression manually lest it is shared. */
872 }
874 /* The stabilization failed. Keep maybe_stable_expr
875 untouched here to let the pointer case below know
876 about that failure. */
877 }
879 /* Case 3: If this is a constant renaming and creating a
880 new object is allowed and cheap, treat it as a normal
881 object whose initial value is what is being renamed. */
883 ;
885 /* Case 4: Make this into a constant pointer to the object we
886 are to rename and attach the object to the pointer if it is
887 something we can stabilize.
889 From the proper scope, attached objects will be referenced
890 directly instead of indirectly via the pointer to avoid
891 subtle aliasing problems with non-addressable entities.
892 They have to be stable because we must not evaluate the
893 variables in the expression every time the renaming is used.
894 The pointer is called a "renaming" pointer in this case.
896 In the rare cases where we cannot stabilize the renamed
897 object, we just make a "bare" pointer, and the renamed
898 entity is always accessed indirectly through it. */
899 else
900 {
905 /* If the previous attempt at stabilizing failed, there
906 is no point in trying again and we reuse the result
907 without attaching it to the pointer. In this case it
908 will only be used as the initializing expression of
909 the pointer and thus needs no special treatment with
910 regard to multiple evaluations. */
912 ;
914 /* Otherwise, try to stabilize and attach the expression
915 to the pointer if the stabilization succeeds.
917 Note that this might introduce SAVE_EXPRs and we don't
918 check whether we're at the global level or not. This
919 is fine since we are building a pointer initializer and
920 neither the pointer nor the initializing expression can
921 be accessed before the pointer elaboration has taken
922 place in a correct program.
924 These SAVE_EXPRs will be evaluated at the right place
925 by either the evaluation of the initializer for the
926 non-global case or the elaboration code for the global
927 case, and will be attached to the elaboration procedure
928 in the latter case. */
929 else
930 {
931 maybe_stable_expr
937 /* Attaching is actually performed downstream, as soon
938 as we have a VAR_DECL for the pointer we make. */
939 }
941 gnu_expr
946 }
947 }
948 }
950 /* If this is an aliased object whose nominal subtype is unconstrained,
951 the object is a record that contains both the template and
952 the object. If there is an initializer, it will have already
953 been converted to the right type, but we need to create the
954 template if there is no initializer. */
958 /* Beware that padding might have been introduced
959 via maybe_pad_type above. */
962 == RECORD_TYPE
963 && TYPE_CONTAINS_TEMPLATE_P
966 {
967 tree template_field
972 gnu_expr
973 = gnat_build_constructor
975 tree_cons
979 NULL_TREE),
980 NULL_TREE));
981 }
983 /* Convert the expression to the type of the object except in the
984 case where the object's type is unconstrained or the object's type
985 is a padded record whose field is of self-referential size. In
986 the former case, converting will generate unnecessary evaluations
987 of the CONSTRUCTOR to compute the size and in the latter case, we
988 want to only copy the actual data. */
994 && (CONTAINS_PLACEHOLDER_P
998 /* If this is a pointer and it does not have an initializing
999 expression, initialize it to NULL, unless the object is
1000 imported. */
1006 /* If we are defining the object and it has an Address clause we must
1007 get the address expression from the saved GCC tree for the
1008 object if the object has a Freeze_Node. Otherwise, we elaborate
1009 the address expression here since the front-end has guaranteed
1010 in that case that the elaboration has no effects. Note that
1011 only the latter mechanism is currently in use. */
1013 {
1014 tree gnu_address
1020 /* Ignore the size. It's either meaningless or was handled
1021 above. */
1023 /* Convert the type of the object to a reference type that can
1024 alias everything as per 13.3(19). */
1025 gnu_type
1031 /* If we don't have an initializing expression for the underlying
1032 variable, the initializing expression for the pointer is the
1033 specified address. Otherwise, we have to make a COMPOUND_EXPR
1034 to assign both the address and the initial value. */
1037 else
1038 gnu_expr
1040 build_binary_op
1043 gnu_address),
1044 gnu_expr),
1045 gnu_address);
1046 }
1048 /* If it has an address clause and we are not defining it, mark it
1049 as an indirect object. Likewise for Stdcall objects that are
1050 imported. */
1054 {
1055 /* Convert the type of the object to a reference type that can
1056 alias everything as per 13.3(19). */
1057 gnu_type
1062 /* No point in taking the address of an initializing expression
1063 that isn't going to be used. */
1066 }
1068 /* If we are at top level and this object is of variable size,
1069 make the actual type a hidden pointer to the real type and
1070 make the initializer be a memory allocation and initialization.
1071 Likewise for objects we aren't defining (presumed to be
1072 external references from other packages), but there we do
1073 not set up an initialization.
1075 If the object's size overflows, make an allocator too, so that
1076 Storage_Error gets raised. Note that we will never free
1077 such memory, so we presume it never will get allocated. */
1082 || (gnu_size
1086 {
1092 /* In case this was a aliased object whose nominal subtype is
1093 unconstrained, the pointer above will be a thin pointer and
1094 build_allocator will automatically make the template.
1096 If we have a template initializer only (that we made above),
1097 pretend there is none and rely on what build_allocator creates
1098 again anyway. Otherwise (if we have a full initializer), get
1099 the data part and feed that to build_allocator.
1101 If we are elaborating a mutable object, tell build_allocator to
1102 ignore a possibly simpler size from the initializer, if any, as
1103 we must allocate the maximum possible size in this case. */
1106 {
1111 {
1112 gnu_alloc_type
1119 else
1120 gnu_expr
1121 = build_component_ref
1125 }
1131 gnat_entity);
1135 }
1136 else
1137 {
1140 }
1141 }
1143 /* If this object would go into the stack and has an alignment larger
1144 than the largest stack alignment the back-end can honor, resort to
1145 a variable of "aligning type". */
1148 {
1149 /* Create the new variable. No need for extra room before the
1150 aligned field as this is in automatic storage. */
1151 tree gnu_new_type
1155 tree gnu_new_var
1160 /* Initialize the aligned field if we have an initializer. */
1162 add_stmt_with_node
1164 build_component_ref
1167 gnu_expr),
1168 gnat_entity);
1170 /* And setup this entity as a reference to the aligned field. */
1172 gnu_expr
1173 = build_unary_op
1181 }
1187 /* Convert the expression to the type of the object except in the
1188 case where the object's type is unconstrained or the object's type
1189 is a padded record whose field is of self-referential size. In
1190 the former case, converting will generate unnecessary evaluations
1191 of the CONSTRUCTOR to compute the size and in the latter case, we
1192 want to only copy the actual data. */
1198 && (CONTAINS_PLACEHOLDER_P
1202 /* If this name is external or there was a name specified, use it,
1203 unless this is a VMS exception object since this would conflict
1204 with the symbol we need to export in addition. Don't use the
1205 Interface_Name if there is an address clause (see CD30005). */
1214 /* If this is constant initialized to a static constant and the
1215 object has an aggregate type, force it to be statically
1216 allocated. */
1232 {
1235 {
1238 }
1239 }
1246 STACK_CHECK_MAX_VAR_SIZE))))
1251 gnat_entity);
1253 /* If this is a public constant or we're not optimizing and we're not
1254 making a VAR_DECL for it, make one just for export or debugger use.
1255 Likewise if the address is taken or if either the object or type is
1256 aliased. Make an external declaration for a reference, unless this
1257 is a Standard entity since there no real symbol at the object level
1258 for these. */
1266 {
1267 tree gnu_corr_var
1271 gnat_entity);
1274 }
1276 /* If this is declared in a block that contains a block with an
1277 exception handler, we must force this variable in memory to
1278 suppress an invalid optimization. */
1285 /* Back-annotate Alignment and Esize of the object if not already
1286 known, except for when the object is actually a pointer to the
1287 real object, since alignment and size of a pointer don't have
1288 anything to do with those of the designated object. Note that
1289 we pick the values of the type, not those of the object, to
1290 shield ourselves from low-level platform-dependent adjustments
1291 like alignment promotion. This is both consistent with all the
1292 treatment above, where alignment and size are set on the type of
1293 the object and not on the object directly, and makes it possible
1294 to support confirming representation clauses in all cases. */
1301 {
1304 gnu_object_size
1308 }
1309 }
1313 /* Return a TYPE_DECL for "void" that we previously made. */
1318 /* A special case, for the types Character and Wide_Character in
1319 Standard, we do not list all the literals. So if the literals
1320 are not specified, make this an unsigned type. */
1322 {
1326 /* Set the TYPE_STRING_FLAG for Ada Character and
1327 Wide_Character types. This is needed by the dwarf-2 debug writer to
1328 distinguish between unsigned integer types and character types. */
1331 }
1333 /* Normal case of non-character type, or non-Standard character type */
1334 {
1335 /* Here we have a list of enumeral constants in First_Literal.
1336 We make a CONST_DECL for each and build into GNU_LITERAL_LIST
1337 the list to be places into TYPE_FIELDS. Each node in the list
1338 is a TREE_LIST node whose TREE_VALUE is the literal name
1339 and whose TREE_PURPOSE is the value of the literal.
1341 Esize contains the number of bits needed to represent the enumeral
1342 type, Type_Low_Bound also points to the first literal and
1343 Type_High_Bound points to the last literal. */
1345 Entity_Id gnat_literal;
1350 else
1358 {
1360 gnu_type);
1361 tree gnu_literal
1369 }
1373 /* Note that the bounds are updated at the end of this function
1374 because to avoid an infinite recursion when we get the bounds of
1375 this type, since those bounds are objects of this type. */
1376 }
1382 /* For integer types, just make a signed type the appropriate number
1383 of bits. */
1388 /* For modular types, make the unsigned type of the proper number of
1389 bits and then set up the modulus, if required. */
1390 {
1392 tree gnu_modulus;
1398 /* Find the smallest mode at least ESIZE bits wide and make a class
1399 using that mode. */
1404 ;
1411 /* Get the modulus in this type. If it overflows, assume it is because
1412 it is equal to 2**Esize. Note that there is no overflow checking
1413 done on unsigned type, so we detect the overflow by looking for
1414 a modulus of zero, which is otherwise invalid. */
1418 {
1423 }
1425 /* If we have to set TYPE_PRECISION different from its natural value,
1426 make a subtype to do do. Likewise if there is a modulus and
1427 it is not one greater than TYPE_MAX_VALUE. */
1431 {
1449 }
1450 }
1459 /* For integral subtypes, we make a new INTEGER_TYPE. Note
1460 that we do not want to call build_range_type since we would
1461 like each subtype node to be distinct. This will be important
1462 when memory aliasing is implemented.
1464 The TREE_TYPE field of the INTEGER_TYPE we make points to the
1465 parent type; this fact is used by the arithmetic conversion
1466 functions.
1468 We elaborate the Ancestor_Subtype if it is not in the current
1469 unit and one of our bounds is non-static. We do this to ensure
1470 consistent naming in the case where several subtypes share the same
1471 bounds by always elaborating the first such subtype first, thus
1472 using its name. */
1485 {
1488 }
1496 gnat_entity,
1503 gnat_entity,
1507 /* One of the above calls might have caused us to be elaborated,
1508 so don't blow up if so. */
1510 {
1513 }
1518 /* This should be an unsigned type if the lower bound is constant
1519 and non-negative or if the base type is unsigned; a signed type
1520 otherwise. */
1530 /* Inherit our alias set from what we're a subtype of. Subtypes
1531 are not different types and a pointer can designate any instance
1532 within a subtype hierarchy. */
1535 /* If the type we are dealing with is to represent a packed array,
1536 we need to have the bits left justified on big-endian targets
1537 and right justified on little-endian targets. We also need to
1538 ensure that when the value is read (e.g. for comparison of two
1539 such values), we only get the good bits, since the unused bits
1540 are uninitialized. Both goals are accomplished by wrapping the
1541 modular value in an enclosing struct. */
1544 {
1546 tree gnu_field;
1553 /* Propagate the alignment of the modular type to the record.
1554 This means that bitpacked arrays have "ceil" alignment for
1555 their size, which may seem counter-intuitive but makes it
1556 possible to easily overlay them on modular types. */
1560 /* Create a stripped-down declaration of the original type, mainly
1561 for debugging. */
1565 /* Don't notify the field as "addressable", since we won't be taking
1566 it's address and it would prevent create_field_decl from making a
1567 bitfield. */
1576 }
1578 /* If the type we are dealing with has got a smaller alignment than the
1579 natural one, we need to wrap it up in a record type and under-align
1580 the latter. We reuse the padding machinery for this purpose. */
1585 {
1587 tree gnu_field;
1595 /* Create a stripped-down declaration of the original type, mainly
1596 for debugging. */
1600 /* Don't notify the field as "addressable", since we won't be taking
1601 it's address and it would prevent create_field_decl from making a
1602 bitfield. */
1611 }
1613 /* Otherwise reset the alignment lest we computed it above. */
1614 else
1620 /* If this is a VAX floating-point type, use an integer of the proper
1621 size. All the operations will be handled with ASM statements. */
1623 {
1628 sizetype));
1630 }
1632 /* The type of the Low and High bounds can be our type if this is
1633 a type from Standard, so set them at the end of the function. */
1641 {
1644 }
1646 {
1673 /* One of the above calls might have caused us to be elaborated,
1674 so don't blow up if so. */
1676 {
1679 }
1683 /* Inherit our alias set from what we're a subtype of, as for
1684 integer subtypes. */
1686 }
1689 /* Array and String Types and Subtypes
1691 Unconstrained array types are represented by E_Array_Type and
1692 constrained array types are represented by E_Array_Subtype. There
1693 are no actual objects of an unconstrained array type; all we have
1694 are pointers to that type.
1696 The following fields are defined on array types and subtypes:
1698 Component_Type Component type of the array.
1699 Number_Dimensions Number of dimensions (an int).
1700 First_Index Type of first index. */
1704 {
1710 int firstdim
1712 int nextdim
1719 tree gnu_max_size_unit;
1720 Entity_Id gnat_ind_subtype;
1721 Entity_Id gnat_ind_base_subtype;
1722 tree gnu_template_reference;
1723 tree tem;
1728 /* Make a node for the array. If we are not defining the array
1729 suppress expanding incomplete types. */
1735 /* Build the fat pointer type. Use a "void *" object instead of
1736 a pointer to the array type since we don't have the array type
1737 yet (it will reference the fat pointer via the bounds). */
1740 ptr_void_type_node,
1743 gnu_ptr_template,
1746 /* Make sure we can put this into a register. */
1749 /* Do not finalize this record type since the types of its fields
1750 are still incomplete at this point. */
1754 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1755 is the fat pointer. This will be used to access the individual
1756 fields once we build them. */
1760 gnu_template_reference
1764 /* Now create the GCC type for each index and add the fields for
1765 that index to the template. */
1767 gnat_ind_base_subtype
1773 {
1775 tree gnu_ind_subtype
1777 tree gnu_base_subtype
1779 tree gnu_base_min
1781 tree gnu_base_max
1785 /* Make the FIELD_DECLs for the minimum and maximum of this
1786 type and then make extractions of that field from the
1787 template. */
1790 gnu_ind_subtype,
1794 gnu_ind_subtype,
1803 /* We can't use build_component_ref here since the template
1804 type isn't complete yet. */
1807 NULL_TREE);
1810 NULL_TREE);
1813 /* Make a range type with the new ranges, but using
1814 the Ada subtype. Then we convert to sizetype. */
1820 gnat_entity);
1821 /* Update the maximum size of the array, in elements. */
1822 gnu_max_size
1826 gnu_base_min)));
1830 }
1833 gnu_template_fields
1836 /* Install all the fields into the template. */
1840 /* Now make the array of arrays and update the pointer to the array
1841 in the fat pointer. Note that it is the first field. */
1844 /* Try to get a smaller form of the component if needed. */
1857 /* Get and validate any specified Component_Size, but if Packed,
1858 ignore it since the front end will have taken care of it. */
1859 gnu_comp_size
1861 gnat_entity,
1866 /* If the component type is a RECORD_TYPE that has a self-referential
1867 size, use the maxium size. */
1873 {
1874 tree orig_tem;
1879 /* If a padding record was made, declare it now since it will
1880 never be declared otherwise. This is necessary to ensure
1881 that its subtrees are properly marked. */
1884 gnat_entity);
1885 }
1891 /* If Component_Size is not already specified, annotate it with the
1892 size of the component. */
1902 gnu_max_size),
1906 {
1911 }
1913 /* If an alignment is specified, use it if valid. But ignore it for
1914 types that represent the unpacked base type for packed arrays. If
1915 the alignment was requested with an explicit user alignment clause,
1916 state so. */
1919 {
1926 }
1932 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
1933 corresponding fat pointer. */
1940 /* If the maximum size doesn't overflow, use it. */
1955 /* Give the fat pointer type a name. */
1960 /* Create the type to be used as what a thin pointer designates: an
1961 record type for the object and its template with the field offsets
1962 shifted to have the template at a negative offset. */
1970 /* Give the thin pointer type a name. */
1974 gnat_entity);
1975 }
1981 /* This is the actual data type for array variables. Multidimensional
1982 arrays are implemented in the gnu tree as arrays of arrays. Note
1983 that for the moment arrays which have sparse enumeration subtypes as
1984 index components create sparse arrays, which is obviously space
1985 inefficient but so much easier to code for now.
1987 Also note that the subtype never refers to the unconstrained
1988 array type, which is somewhat at variance with Ada semantics.
1990 First check to see if this is simply a renaming of the array
1991 type. If so, the result is the array type. */
1996 else
1997 {
2000 int first_dim
2003 int next_dim
2005 Entity_Id gnat_ind_subtype;
2006 Entity_Id gnat_ind_base_subtype;
2011 tree gnu_max_size_unit;
2015 /* First create the gnu types for each index. Create types for
2016 debugging information to point to the index types if the
2017 are not integer types, have variable bounds, or are
2018 wider than sizetype. */
2021 gnat_ind_base_subtype
2027 {
2028 tree gnu_index_subtype
2030 tree gnu_min
2032 tree gnu_max
2034 tree gnu_base_subtype
2036 tree gnu_base_min
2038 tree gnu_base_max
2041 tree gnu_base_base_min
2043 tree gnu_base_base_max
2045 tree gnu_high;
2046 tree gnu_this_max;
2048 /* If the minimum and maximum values both overflow in
2049 SIZETYPE, but the difference in the original type
2050 does not overflow in SIZETYPE, ignore the overflow
2051 indications. */
2059 && (!TREE_OVERFLOW
2063 {
2066 }
2068 /* Similarly, if the range is null, use bounds of 1..0 for
2069 the sizetype bounds. */
2081 /* Now compute the size of this bound. We need to provide
2082 GCC with an upper bound to use but have to deal with the
2083 "superflat" case. There are three ways to do this. If we
2084 can prove that the array can never be superflat, we can
2085 just use the high bound of the index subtype. If we can
2086 prove that the low bound minus one can't overflow, we
2087 can do this as MAX (hb, lb - 1). Otherwise, we have to use
2088 the expression hb >= lb ? hb : lb - 1. */
2091 /* See if the base array type is already flat. If it is, we
2092 are probably compiling an ACVC test, but it will cause the
2093 code below to malfunction if we don't handle it specially. */
2101 /* If gnu_high is now an integer which overflowed, the array
2102 cannot be superflat. */
2109 else
2110 gnu_high
2111 = build_cond_expr
2118 gnat_entity);
2120 /* Also compute the maximum size of the array. Here we
2121 see if any constraint on the index type of the base type
2122 can be used in the case of self-referential bound on
2123 the index type of the subtype. We look for a non-"infinite"
2124 and non-self-referential bound from any type involved and
2125 handle each bound separately. */
2154 gnu_this_max
2158 gnu_base_min)),
2159 size_zero_node);
2165 gnu_max_size
2179 }
2181 /* Then flatten: create the array of arrays. For an array type
2182 used to implement a packed array, get the component type from
2183 the original array type since the representation clauses that
2184 can affect it are on the latter. */
2187 {
2192 /* One of the above calls might have caused us to be elaborated,
2193 so don't blow up if so. */
2195 {
2198 }
2199 }
2200 else
2201 {
2204 /* One of the above calls might have caused us to be elaborated,
2205 so don't blow up if so. */
2207 {
2210 }
2212 /* Try to get a smaller form of the component if needed. */
2222 /* Get and validate any specified Component_Size, but if Packed,
2223 ignore it since the front end will have taken care of it. */
2224 gnu_comp_size
2226 gnat_entity,
2231 /* If the component type is a RECORD_TYPE that has a
2232 self-referential size, use the maxium size. */
2239 {
2240 tree orig_gnu_type;
2241 gnu_type
2247 /* If a padding record was made, declare it now since it
2248 will never be declared otherwise. This is necessary
2249 to ensure that its subtrees are properly marked. */
2253 }
2259 }
2268 {
2273 }
2275 /* If we are at file level and this is a multi-dimensional array, we
2276 need to make a variable corresponding to the stride of the
2277 inner dimensions. */
2279 {
2281 tree gnu_arr_type;
2287 {
2295 /* ??? For now, store the size as a multiple of the
2296 alignment of the element type in bytes so that we
2297 can see the alignment from the tree. */
2299 = build_binary_op
2301 elaborate_expression_1
2311 /* ??? create_type_decl is not invoked on the inner types so
2312 the MULT_EXPR node built above will never be marked. */
2314 }
2315 }
2317 /* If we need to write out a record type giving the names of
2318 the bounds, do it now. */
2320 {
2323 tree gnu_field;
2329 {
2330 tree gnu_type_name
2337 integer_type_node,
2338 gnu_bound_rec_type,
2342 }
2346 }
2354 /* If our size depends on a placeholder and the maximum size doesn't
2355 overflow, use it. */
2362 {
2368 }
2370 /* Set our alias set to that of our base type. This gives all
2371 array subtypes the same alias set. */
2373 }
2375 /* If this is a packed type, make this type the same as the packed
2376 array type, but do some adjusting in the type first. */
2379 {
2380 Entity_Id gnat_index;
2381 tree gnu_inner_type;
2383 /* First finish the type we had been making so that we output
2384 debugging information for it */
2385 gnu_type
2388 | (TYPE_QUAL_VOLATILE
2396 /* Save it as our equivalent in case the call below elaborates
2397 this type again. */
2412 /* We need to point the type we just made to our index type so
2413 the actual bounds can be put into a template. */
2419 {
2421 {
2422 /* The TYPE_ACTUAL_BOUNDS field is also used for the modulus.
2423 If it is, we need to make another type. */
2425 {
2426 tree gnu_subtype;
2443 }
2446 }
2452 SET_TYPE_ACTUAL_BOUNDS
2459 SET_TYPE_ACTUAL_BOUNDS
2466 }
2467 }
2469 /* Abort if packed array with no packed array type field set. */
2470 else
2476 /* Create the type for a string literal. */
2477 {
2478 Entity_Id gnat_full_type
2483 tree gnu_string_array_type
2485 tree gnu_string_index_type
2488 tree gnu_lower_bound
2493 tree gnu_upper_bound
2495 gnu_lower_bound,
2497 tree gnu_range_type
2500 tree gnu_index_type
2507 gnu_type
2509 gnu_index_type);
2511 }
2514 /* Record Types and Subtypes
2516 The following fields are defined on record types:
2518 Has_Discriminants True if the record has discriminants
2519 First_Discriminant Points to head of list of discriminants
2520 First_Entity Points to head of list of fields
2521 Is_Tagged_Type True if the record is tagged
2523 Implementation of Ada records and discriminated records:
2525 A record type definition is transformed into the equivalent of a C
2526 struct definition. The fields that are the discriminants which are
2527 found in the Full_Type_Declaration node and the elements of the
2528 Component_List found in the Record_Type_Definition node. The
2529 Component_List can be a recursive structure since each Variant of
2530 the Variant_Part of the Component_List has a Component_List.
2532 Processing of a record type definition comprises starting the list of
2533 field declarations here from the discriminants and the calling the
2534 function components_to_record to add the rest of the fields from the
2535 component list and return the gnu type node. The function
2536 components_to_record will call itself recursively as it traverses
2537 the tree. */
2541 {
2542 gnu_type
2543 = build_complex_type
2544 (get_unpadded_type
2547 (Component_List
2548 (Type_Definition
2552 }
2554 {
2557 Entity_Id gnat_field;
2558 tree gnu_field;
2560 tree gnu_get_parent;
2561 /* Set PACKED in keeping with gnat_to_gnu_field. */
2562 int packed
2574 bool is_extension
2578 /* See if all fields have a rep clause. Stop when we find one
2579 that doesn't. */
2588 /* If this is a record extension, go a level further to find the
2589 record definition. Also, verify we have a Parent_Subtype. */
2591 {
2598 }
2600 /* Make a node for the record. If we are not defining the record,
2601 suppress expanding incomplete types. */
2609 /* If both a size and rep clause was specified, put the size in
2610 the record type now so that it can get the proper mode. */
2614 /* Always set the alignment here so that it can be used to
2615 set the mode, if it is making the alignment stricter. If
2616 it is invalid, it will be checked again below. If this is to
2617 be Atomic, choose a default alignment of a word unless we know
2618 the size and it's smaller. */
2625 /* If a type needs strict alignment, the minimum size will be the
2626 type size instead of the RM size (see validate_size). Cap the
2627 alignment, lest it causes this type size to become too large. */
2630 {
2635 }
2636 else
2639 /* If we have a Parent_Subtype, make a field for the parent. If
2640 this record has rep clauses, force the position to zero. */
2642 {
2644 tree gnu_parent;
2646 /* A major complexity here is that the parent subtype will
2647 reference our discriminants in its Discriminant_Constraint
2648 list. But those must reference the parent component of this
2649 record which is of the parent subtype we have not built yet!
2650 To break the circle we first build a dummy COMPONENT_REF which
2651 represents the "get to the parent" operation and initialize
2652 each of those discriminants to a COMPONENT_REF of the above
2653 dummy parent referencing the corresponding discriminant of the
2654 base type of the parent subtype. */
2658 void_type_node),
2659 NULL_TREE);
2666 save_gnu_tree
2670 gnu_get_parent,
2673 NULL_TREE),
2676 /* Then we build the parent subtype. */
2679 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
2680 initially built. The discriminants must reference the fields
2681 of the parent subtype and not those of its base type for the
2682 placeholder machinery to properly work. */
2688 {
2698 }
2700 /* The "get to the parent" COMPONENT_REF must be given its
2701 proper type... */
2704 /* ...and reference the _parent field of this record. */
2705 gnu_field_list
2713 }
2715 /* Make the fields for the discriminants and put them into the record
2716 unless it's an Unchecked_Union. */
2721 {
2722 /* If this is a record extension and this discriminant
2723 is the renaming of another discriminant, we've already
2724 handled the discriminant above. */
2729 gnu_field
2732 /* Make an expression using a PLACEHOLDER_EXPR from the
2733 FIELD_DECL node just created and link that with the
2734 corresponding GNAT defining identifier. Then add to the
2735 list of fields. */
2744 {
2747 }
2748 }
2750 /* Put the discriminants into the record (backwards), so we can
2751 know the appropriate discriminant to use for the names of the
2752 variants. */
2755 /* Add the listed fields into the record and finish it up. */
2761 /* We used to remove the associations of the discriminants and
2762 _Parent for validity checking, but we may need them if there's
2763 Freeze_Node for a subtype used in this record. */
2767 /* If it is a tagged record force the type to BLKmode to insure
2768 that these objects will always be placed in memory. Do the
2769 same thing for limited record types. */
2773 /* If this is a derived type, we must make the alias set of this type
2774 the same as that of the type we are derived from. We assume here
2775 that the other type is already frozen. */
2781 /* Fill in locations of fields. */
2784 /* If there are any entities in the chain corresponding to
2785 components that we did not elaborate, ensure we elaborate their
2786 types if they are Itypes. */
2794 }
2798 /* If an equivalent type is present, that is what we should use.
2799 Otherwise, fall through to handle this like a record subtype
2800 since it may have constraints. */
2802 {
2806 }
2808 /* ... fall through ... */
2812 /* If Cloned_Subtype is Present it means this record subtype has
2813 identical layout to that type or subtype and we should use
2814 that GCC type for this one. The front end guarantees that
2815 the component list is shared. */
2817 {
2821 }
2823 /* Otherwise, first ensure the base type is elaborated. Then, if we are
2824 changing the type, make a new type with each field having the
2825 type of the field in the new subtype but having the position
2826 computed by transforming every discriminant reference according
2827 to the constraints. We don't see any difference between
2828 private and nonprivate type here since derivations from types should
2829 have been deferred until the completion of the private type. */
2830 else
2831 {
2833 tree gnu_base_type;
2834 tree gnu_orig_type;
2839 /* Get the base type initially for its alignment and sizes. But
2840 if it is a padded type, we do all the other work with the
2841 unpadded type. */
2847 else
2851 {
2854 }
2856 /* When the type has discriminants, and these discriminants
2857 affect the shape of what it built, factor them in.
2859 If we are making a subtype of an Unchecked_Union (must be an
2860 Itype), just return the type.
2862 We can't just use Is_Constrained because private subtypes without
2863 discriminants of full types with discriminants with default
2864 expressions are Is_Constrained but aren't constrained! */
2872 {
2873 Entity_Id gnat_field;
2875 tree gnu_pos_list
2878 BIGGEST_ALIGNMENT);
2879 tree gnu_subst_list
2881 definition);
2882 tree gnu_temp;
2898 {
2899 tree gnu_old_field
2902 tree gnu_offset
2904 gnu_pos_list));
2907 tree gnu_field_type
2911 unsigned int offset_align
2914 tree gnu_field;
2916 /* If there was a component clause, the field types must be
2917 the same for the type and subtype, so copy the data from
2918 the old field to avoid recomputation here. Also if the
2919 field is justified modular and the optimization in
2920 gnat_to_gnu_field was applied. */
2927 {
2930 }
2932 /* If the old field was packed and of constant size, we
2933 have to get the old size here, as it might differ from
2934 what the Etype conveys and the latter might overlap
2935 onto the following field. Try to arrange the type for
2936 possible better packing along the way. */
2940 {
2945 gnu_field_type
2947 }
2956 /* If the size is now a constant, we can set it as the
2957 size of the field when we make it. Otherwise, we need
2958 to deal with it specially. */
2962 gnu_field
2963 = create_field_decl
2969 {
2978 bitsize_unit_node));
2980 }
2984 SET_DECL_ORIGINAL_FIELD
2995 }
2997 /* Now go through the entities again looking for Itypes that
2998 we have not elaborated but should (e.g., Etypes of fields
2999 that have Original_Components). */
3007 /* Do not finalize it since we're going to modify it below. */
3011 /* Now set the size, alignment and alias set of the new type to
3012 match that of the old one, doing any substitutions, as
3013 above. */
3039 SET_TYPE_ADA_SIZE
3044 /* Reapply variable_size since we have changed the sizes. */
3049 /* Recompute the mode of this record type now that we know its
3050 actual size. */
3053 /* Fill in locations of fields. */
3056 /* We've built a new type, make an XVS type to show what this
3057 is a subtype of. Some debuggers require the XVS type to be
3058 output first, so do it in that order. */
3060 {
3071 integer_type_node,
3072 gnu_subtype_marker,
3076 }
3078 /* Now we can finalize it. */
3080 }
3082 /* Otherwise, go down all the components in the new type and
3083 make them equivalent to those in the base type. */
3084 else
3091 gnat_to_gnu_field_decl
3093 }
3097 /* Use the special descriptor type for dispatch tables if needed,
3098 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3099 Note that we are only required to do so for static tables in
3100 order to be compatible with the C++ ABI, but Ada 2005 allows
3101 to extend library level tagged types at the local level so
3102 we do it in the non-static case as well. */
3105 {
3109 }
3111 /* ... fall through ... */
3114 /* If we are not defining this entity, and we have incomplete
3115 entities being processed above us, make a dummy type and
3116 fill it in later. */
3118 {
3122 gnu_type
3123 = build_pointer_type
3138 }
3140 /* ... fall through ... */
3147 {
3150 bool is_from_limited_with
3154 /* Get the "full view" of this entity. If this is an incomplete
3155 entity from a limited with, treat its non-limited view as the full
3156 view. Otherwise, if this is an incomplete or private type, use the
3157 full view. In the former case, we might point to a private type,
3158 in which case, we need its full view. Also, we want to look at the
3159 actual type used for the representation, so this takes a total of
3160 three steps. */
3161 Entity_Id gnat_desig_full_direct_first
3165 Entity_Id gnat_desig_full_direct
3166 = ((is_from_limited_with
3171 Entity_Id gnat_desig_full
3174 /* This the type actually used to represent the designated type,
3175 either gnat_desig_full or gnat_desig_equiv. */
3176 Entity_Id gnat_desig_rep;
3178 /* Nonzero if this is a pointer to an unconstrained array. */
3181 /* We want to know if we'll be seeing the freeze node for any
3182 incomplete type we may be pointing to. */
3183 bool in_main_unit
3188 /* Nonzero if we make a dummy type here. */
3190 /* Nonzero if the dummy is a fat pointer. */
3198 /* If either the designated type or its full view is an unconstrained
3199 array subtype, replace it with the type it's a subtype of. This
3200 avoids problems with multiple copies of unconstrained array types.
3201 Likewise, if the designated type is a subtype of an incomplete
3202 record type, use the parent type to avoid order of elaboration
3203 issues. This can lose some code efficiency, but there is no
3204 alternative. */
3215 /* Now set the type that actually marks the representation of
3216 the designated type and also flag whether we have a unconstrained
3217 array. */
3219 is_unconstrained_array
3223 /* If we are pointing to an incomplete type whose completion is an
3224 unconstrained array, make a fat pointer type. The two types in our
3225 fields will be pointers to dummy nodes and will be replaced in
3226 update_pointer_to. Similarly, if the type itself is a dummy type or
3227 an unconstrained array. Also make a dummy TYPE_OBJECT_RECORD_TYPE
3228 in case we have any thin pointers to it. */
3239 {
3240 tree gnu_old
3244 tree fields;
3246 /* Show the dummy we get will be a fat pointer. */
3249 /* If the call above got something that has a pointer, that
3250 pointer is our type. This could have happened either
3251 because the type was elaborated or because somebody
3252 else executed the code below. */
3255 {
3276 fields
3278 create_field_decl
3280 gnu_ptr_array,
3283 gnu_ptr_template,
3286 /* Make sure we can place this into a register. */
3291 /* Do not finalize this record type since the types of
3292 its fields are incomplete. */
3300 }
3301 }
3303 /* If we already know what the full type is, use it. */
3308 /* Get the type of the thing we are to point to and build a pointer
3309 to it. If it is a reference to an incomplete or private type with a
3310 full view that is a record, make a dummy type node and get the
3311 actual type later when we have verified it is safe. */
3317 /* Likewise if we are pointing to a record or array and we
3318 are to defer elaborating incomplete types. We do this
3319 since this access type may be the full view of some
3320 private type. Note that the unconstrained array case is
3321 handled above. */
3327 /* If this is a reference from a limited_with type back to our
3328 main unit and there's a Freeze_Node for it, either we have
3329 already processed the declaration and made the dummy type,
3330 in which case we just reuse the latter, or we have not yet,
3331 in which case we make the dummy type and it will be reused
3332 when the declaration is processed. In both cases, the
3333 pointer eventually created below will be automatically
3334 adjusted when the Freeze_Node is processed. Note that the
3335 unconstrained array case is handled above. */
3338 {
3341 }
3343 /* Otherwise handle the case of a pointer to itself. */
3345 {
3346 gnu_type
3350 }
3352 /* If expansion is disabled, the equivalent type of a concurrent
3353 type is absent, so build a dummy pointer type. */
3357 /* Finally, handle the straightforward case where we can just
3358 elaborate our designated type and point to it. */
3359 else
3362 /* It is possible that a call to gnat_to_gnu_type above resolved our
3363 type. If so, just return it. */
3365 {
3368 }
3370 /* If we have a GCC type for the designated type, possibly modify it
3371 if we are pointing only to constant objects and then make a pointer
3372 to it. Don't do this for unconstrained arrays. */
3374 {
3377 {
3378 gnu_desig_type
3379 = build_qualified_type
3383 /* Some extra processing is required if we are building a
3384 pointer to an incomplete type (in the GCC sense). We might
3385 have such a type if we just made a dummy, or directly out
3386 of the call to gnat_to_gnu_type above if we are processing
3387 an access type for a record component designating the
3388 record type itself. */
3390 {
3391 /* We must ensure that the pointer to variant we make will
3392 be processed by update_pointer_to when the initial type
3393 is completed. Pretend we made a dummy and let further
3394 processing act as usual. */
3397 /* We must ensure that update_pointer_to will not retrieve
3398 the dummy variant when building a properly qualified
3399 version of the complete type. We take advantage of the
3400 fact that get_qualified_type is requiring TYPE_NAMEs to
3401 match to influence build_qualified_type and then also
3402 update_pointer_to here. */
3405 }
3406 }
3408 gnu_type
3411 }
3413 /* If we are not defining this object and we made a dummy pointer,
3414 save our current definition, evaluate the actual type, and replace
3415 the tentative type we made with the actual one. If we are to defer
3416 actually looking up the actual type, make an entry in the
3417 deferred list. If this is from a limited with, we have to defer
3418 to the end of the current spec in two cases: first if the
3419 designated type is in the current unit and second if the access
3420 type is. */
3422 {
3423 tree gnu_old_type
3429 gnu_type
3430 = build_pointer_type
3431 (TYPE_OBJECT_RECORD_TYPE
3443 && ! (is_from_limited_with
3444 && (in_main_unit
3449 /* Note that the call to gnat_to_gnu_type here might have
3450 updated gnu_old_type directly, in which case it is not a
3451 dummy type any more when we get into update_pointer_to.
3453 This may happen for instance when the designated type is a
3454 record type, because their elaboration starts with an
3455 initial node from make_dummy_type, which may yield the same
3456 node as the one we got.
3458 Besides, variants of this non-dummy type might have been
3459 created along the way. update_pointer_to is expected to
3460 properly take care of those situations. */
3461 else
3462 {
3467 = (is_from_limited_with
3468 && (in_main_unit
3476 }
3477 }
3478 }
3485 else
3486 {
3487 /* The runtime representation is the equivalent type. */
3490 }
3503 /* We treat this as identical to its base type; any constraint is
3504 meaningful only to the front end.
3506 The designated type must be elaborated as well, if it does
3507 not have its own freeze node. Designated (sub)types created
3508 for constrained components of records with discriminants are
3509 not frozen by the front end and thus not elaborated by gigi,
3510 because their use may appear before the base type is frozen,
3511 and because it is not clear that they are needed anywhere in
3512 Gigi. With the current model, there is no correct place where
3513 they could be elaborated. */
3520 {
3521 /* If we are not defining this entity, and we have incomplete
3522 entities being processed above us, make a dummy type and
3523 elaborate it later. */
3525 {
3528 tree gnu_ptr_type
3529 = build_pointer_type
3536 }
3539 Incomplete_Or_Private_Kind))
3542 }
3547 /* Subprogram Entities
3549 The following access functions are defined for subprograms (functions
3550 or procedures):
3552 First_Formal The first formal parameter.
3553 Is_Imported Indicates that the subprogram has appeared in
3554 an INTERFACE or IMPORT pragma. For now we
3555 assume that the external language is C.
3556 Is_Exported Likewise but for an EXPORT pragma.
3557 Is_Inlined True if the subprogram is to be inlined.
3559 In addition for function subprograms we have:
3561 Etype Return type of the function.
3563 Each parameter is first checked by calling must_pass_by_ref on its
3564 type to determine if it is passed by reference. For parameters which
3565 are copied in, if they are Ada In Out or Out parameters, their return
3566 value becomes part of a record which becomes the return type of the
3567 function (C function - note that this applies only to Ada procedures
3568 so there is no Ada return type). Additional code to store back the
3569 parameters will be generated on the caller side. This transformation
3570 is done here, not in the front-end.
3572 The intended result of the transformation can be seen from the
3573 equivalent source rewritings that follow:
3575 struct temp {int a,b};
3576 procedure P (A,B: In Out ...) is temp P (int A,B)
3577 begin {
3578 .. ..
3579 end P; return {A,B};
3580 }
3582 temp t;
3583 P(X,Y); t = P(X,Y);
3584 X = t.a , Y = t.b;
3586 For subprogram types we need to perform mainly the same conversions to
3587 GCC form that are needed for procedures and function declarations. The
3588 only difference is that at the end, we make a type declaration instead
3589 of a function declaration. */
3594 {
3595 /* The first GCC parameter declaration (a PARM_DECL node). The
3596 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3597 actually is the head of this parameter list. */
3599 /* Likewise for the stub associated with an exported procedure. */
3601 /* The type returned by a function. If the subprogram is a procedure
3602 this type should be void_type_node. */
3604 /* List of fields in return type of procedure with copy-in copy-out
3605 parameters. */
3607 /* Non-null for subprograms containing parameters passed by copy-in
3608 copy-out (Ada In Out or Out parameters not passed by reference),
3609 in which case it is the list of nodes used to specify the values of
3610 the in out/out parameters that are returned as a record upon
3611 procedure return. The TREE_PURPOSE of an element of this list is
3612 a field of the record and the TREE_VALUE is the PARM_DECL
3613 corresponding to that field. This list will be saved in the
3614 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3616 /* If an import pragma asks to map this subprogram to a GCC builtin,
3617 this is the builtin DECL node. */
3619 /* For the stub associated with an exported procedure. */
3622 Entity_Id gnat_param;
3625 bool extern_flag
3637 /* A parameter may refer to this type, so defer completion
3638 of any incomplete types. */
3641 /* If the subprogram has an alias, it is probably inherited, so
3642 we can use the original one. If the original "subprogram"
3643 is actually an enumeration literal, it may be the first use
3644 of its type, so we must elaborate that type now. */
3646 {
3653 /* Elaborate any Itypes in the parameters of this entity. */
3661 }
3663 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3664 corresponding DECL node.
3666 We still want the parameter associations to take place because the
3667 proper generation of calls depends on it (a GNAT parameter without
3668 a corresponding GCC tree has a very specific meaning), so we don't
3669 just break here. */
3673 /* ??? What if we don't find the builtin node above ? warn ? err ?
3674 In the current state we neither warn nor err, and calls will just
3675 be handled as for regular subprograms. */
3680 /* If this function returns by reference, make the actual
3681 return type of this function the pointer and mark the decl. */
3683 {
3686 }
3688 /* If the Mechanism is By_Reference, ensure the return type uses
3689 the machine's by-reference mechanism, which may not the same
3690 as above (e.g., it might be by passing a fake parameter). */
3693 {
3696 /* We expect this bit to be reset by gigi shortly, so can avoid a
3697 type node copy here. This actually also prevents troubles with
3698 the generation of debug information for the function, because
3699 we might have issued such info for this type already, and would
3700 be attaching a distinct type node to the function if we made a
3701 copy here. */
3702 }
3704 /* If we are supposed to return an unconstrained array,
3705 actually return a fat pointer and make a note of that. Return
3706 a pointer to an unconstrained record of variable size. */
3708 {
3711 }
3713 /* If the type requires a transient scope, the result is allocated
3714 on the secondary stack, so the result type of the function is
3715 just a pointer. */
3717 {
3720 }
3722 /* If the type is a padded type and the underlying type would not
3723 be passed by reference or this function has a foreign convention,
3724 return the underlying type. */
3732 /* If the return type has a non-constant size, we convert the function
3733 into a procedure and its caller will pass a pointer to an object as
3734 the first parameter when we call the function. This can happen for
3735 an unconstrained type with a maximum size or a constrained type with
3736 a size not known at compile time. */
3739 {
3741 gnu_param_list
3746 }
3748 /* If the return type has a size that overflows, we cannot have
3749 a function that returns that type. This usage doesn't make
3750 sense anyway, so give an error here. */
3754 {
3756 gnat_entity);
3762 }
3764 /* Look at all our parameters and get the type of
3765 each. While doing this, build a copy-out structure if
3766 we need one. */
3768 /* Loop over the parameters and get their associated GCC tree.
3769 While doing this, build a copy-out structure if we need one. */
3773 {
3780 /* Builtins are expanded inline and there is no real call sequence
3781 involved. So the type expected by the underlying expander is
3782 always the type of each argument "as is". */
3785 /* Handle the first parameter of a valued procedure specially. */
3788 /* Otherwise, see if a Mechanism was supplied that forced this
3789 parameter to be passed one way or another. */
3792 ;
3796 {
3800 mech))
3802 else
3804 }
3805 else
3806 {
3809 }
3811 gnu_param
3816 /* We are returned either a PARM_DECL or a type if no parameter
3817 needs to be passed; in either case, adjust the type. */
3820 else
3821 {
3824 }
3827 {
3828 /* If it's an exported subprogram, we build a parameter list
3829 in parallel, in case we need to emit a stub for it. */
3831 {
3832 gnu_stub_param_list
3834 /* Change By_Descriptor parameter to By_Reference for
3835 the internal version of an exported subprogram. */
3837 {
3838 gnu_param
3843 }
3844 else
3846 }
3853 /* If a parameter is a pointer, this function may modify
3854 memory through it and thus shouldn't be considered
3855 a pure function. Also, the memory may be modified
3856 between two calls, so they can't be CSE'ed. The latter
3857 case also handles by-ref parameters. */
3861 }
3864 {
3866 {
3871 }
3880 gnu_return_list);
3881 }
3882 }
3884 /* Do not compute record for out parameters if subprogram is
3885 stubbed since structures are incomplete for the back-end. */
3890 /* If we have a CICO list but it has only one entry, we convert
3891 this function into a function that simply returns that one
3892 object. */
3897 prepend_one_attribute_to
3900 gnat_entity);
3902 /* The lists have been built in reverse. */
3912 gnu_type
3918 gnu_stub_type
3923 /* A subprogram (something that doesn't return anything) shouldn't
3924 be considered Pure since there would be no reason for such a
3925 subprogram. Note that procedures with Out (or In Out) parameters
3926 have already been converted into a function with a return type. */
3930 /* The semantics of "pure" in Ada essentially matches that of "const"
3931 in the back-end. In particular, both properties are orthogonal to
3932 the "nothrow" property. But this is true only if the EH circuitry
3933 is explicit in the internal representation of the back-end. If we
3934 are to completely hide the EH circuitry from it, we need to declare
3935 that calls to pure Ada subprograms that can throw have side effects
3936 since they can trigger an "abnormal" transfer of control flow; thus
3937 they can be neither "const" nor "pure" in the back-end sense. */
3938 gnu_type
3948 gnu_stub_type
3955 /* If we have a builtin decl for that function, check the signatures
3956 compatibilities. If the signatures are compatible, use the builtin
3957 decl. If they are not, we expect the checker predicate to have
3958 posted the appropriate errors, and just continue with what we have
3959 so far. */
3961 {
3965 {
3969 }
3970 }
3972 /* If there was no specified Interface_Name and the external and
3973 internal names of the subprogram are the same, only use the
3974 internal name to allow disambiguation of nested subprograms. */
3978 /* If we are defining the subprogram and it has an Address clause
3979 we must get the address expression from the saved GCC tree for the
3980 subprogram if it has a Freeze_Node. Otherwise, we elaborate
3981 the address expression here since the front-end has guaranteed
3982 in that case that the elaboration has no effects. If there is
3983 an Address clause and we are not defining the object, just
3984 make it a constant. */
3986 {
3990 gnu_address
3997 /* Convert the type of the object to a reference type that can
3998 alias everything as per 13.3(19). */
3999 gnu_type
4004 gnu_decl
4009 }
4015 else
4016 {
4018 {
4022 }
4028 gnat_entity);
4030 {
4031 tree gnu_stub_decl
4036 gnat_entity);
4038 }
4040 /* This is unrelated to the stub built right above. */
4043 }
4044 }
4055 {
4056 /* Get the "full view" of this entity. If this is an incomplete
4057 entity from a limited with, treat its non-limited view as the
4058 full view. Otherwise, use either the full view or the underlying
4059 full view, whichever is present. This is used in all the tests
4060 below. */
4061 Entity_Id full_view
4069 /* If this is an incomplete type with no full view, it must be a Taft
4070 Amendment type, in which case we return a dummy type. Otherwise,
4071 just get the type from its Etype. */
4073 {
4076 else
4077 {
4081 }
4083 }
4085 /* If we already made a type for the full view, reuse it. */
4087 {
4090 }
4092 /* Otherwise, if we are not defining the type now, get the type
4093 from the full view. But always get the type from the full view
4094 for define on use types, since otherwise we won't see them! */
4100 {
4104 }
4106 /* For incomplete types, make a dummy type entry which will be
4107 replaced later. */
4110 /* Save this type as the full declaration's type so we can do any
4111 needed updates when we see it. */
4117 }
4119 /* Simple class_wide types are always viewed as their root_type
4120 by Gigi unless an Equivalent_Type is specified. */
4132 else
4144 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4145 we've already saved it, so we don't try to. */
4152 }
4154 /* If we had a case where we evaluated another type and it might have
4155 defined this one, handle it here. */
4157 {
4160 }
4162 /* If we are processing a type and there is either no decl for it or
4163 we just made one, do some common processing for the type, such as
4164 handling alignment and possible padding. */
4167 {
4175 /* ??? Don't set the size for a String_Literal since it is either
4176 confirming or we don't handle it properly (if the low bound is
4177 non-constant). */
4183 /* If a size was specified, see if we can make a new type of that size
4184 by rearranging the type, for example from a fat to a thin pointer. */
4186 {
4187 gnu_type
4194 }
4196 /* If the alignment hasn't already been processed and this is
4197 not an unconstrained array, see if an alignment is specified.
4198 If not, we pick a default alignment for atomic objects. */
4200 ;
4202 {
4206 /* Warn on suspiciously large alignments. This should catch
4207 errors about the (alignment,byte)/(size,bit) discrepancy. */
4209 {
4210 tree size;
4212 /* If a size was specified, take it into account. Otherwise
4213 use the RM size for records as the type size has already
4214 been adjusted to the alignment. */
4222 else
4225 /* Consider an alignment as suspicious if the alignment/size
4226 ratio is greater or equal to the byte/bit ratio. */
4231 gnat_entity);
4232 }
4233 }
4244 /* See if we need to pad the type. If we did, and made a record,
4245 the name of the new type may be changed. So get it back for
4246 us when we make the new TYPE_DECL below. */
4253 {
4257 }
4261 /* If we are at global level, GCC will have applied variable_size to
4262 the type, but that won't have done anything. So, if it's not
4263 a constant or self-referential, call elaborate_expression_1 to
4264 make a variable for the size rather than calculating it each time.
4265 Handle both the RM size and the actual size. */
4270 {
4274 {
4281 }
4282 else
4283 {
4290 /* ??? For now, store the size as a multiple of the alignment
4291 in bytes so that we can see the alignment from the tree. */
4293 = build_binary_op
4295 elaborate_expression_1
4306 SET_TYPE_ADA_SIZE
4309 gnat_entity,
4313 }
4314 }
4316 /* If this is a record type or subtype, call elaborate_expression_1 on
4317 any field position. Do this for both global and local types.
4318 Skip any fields that we haven't made trees for to avoid problems with
4319 class wide types. */
4324 {
4327 /* ??? Unfortunately, GCC needs to be able to prove the
4328 alignment of this offset and if it's a variable, it can't.
4329 In GCC 3.4, we'll use DECL_OFFSET_ALIGN in some way, but
4330 right now, we have to put in an explicit multiply and
4331 divide by that value. */
4333 {
4335 = build_binary_op
4337 elaborate_expression_1
4347 /* ??? The context of gnu_field is not necessarily gnu_type so
4348 the MULT_EXPR node built above may not be marked by the call
4349 to create_type_decl below. Mark it manually for now. */
4352 }
4353 }
4357 | (TYPE_QUAL_VOLATILE
4373 else
4375 }
4378 {
4381 /* Back-annotate the Alignment of the type if not already in the
4382 tree. Likewise for sizes. */
4388 {
4389 /* If the size is self-referential, we annotate the maximum
4390 value of that size. */
4399 {
4400 /* In this mode the tag and the parent components are not
4401 generated by the front-end, so the sizes must be adjusted
4402 explicitly now. */
4406 {
4407 size_offset
4411 }
4412 else
4420 }
4421 }
4425 }
4435 /* If we haven't already, associate the ..._DECL node that we just made with
4436 the input GNAT entity node. */
4440 /* If this is an enumeral or floating-point type, we were not able to set
4441 the bounds since they refer to the type. These bounds are always static.
4443 For enumeration types, also write debugging information and declare the
4444 enumeration literal table, if needed. */
4448 {
4451 /* If this is a padded type, we need to use the underlying type. */
4456 /* If this is a floating point type and we haven't set a floating
4457 point type yet, use this in the evaluation of the bounds. */
4467 {
4468 /* Since this has both a typedef and a tag, avoid outputting
4469 the name twice. */
4472 }
4473 }
4475 /* If we deferred processing of incomplete types, re-enable it. If there
4476 were no other disables and we have some to process, do so. */
4478 {
4480 {
4483 /* We are back to level 0 for the deferring of incomplete types.
4484 But processing these incomplete types below may itself require
4485 deferring, so preserve what we have and restart from scratch. */
4489 /* For finalization, however, all types must be complete so we
4490 cannot do the same because deferred incomplete types may end up
4491 referencing each other. Process them all recursively first. */
4492 defer_finalize_level++;
4495 {
4502 }
4504 defer_finalize_level--;
4505 }
4507 /* All the deferred incomplete types have been processed so we can
4508 now proceed with the finalization of the deferred types. */
4510 {
4512 tree t;
4518 }
4519 }
4521 /* If we are not defining this type, see if it's in the incomplete list.
4522 If so, handle that list entry now. */
4524 {
4529 {
4533 }
4534 }
4537 force_global--;
4546 }
4548 /* Similar, but if the returned value is a COMPONENT_REF, return the
4549 FIELD_DECL. */
4551 tree
4553 {
4560 }
4562 /* Wrap up compilation of DECL, a TYPE_DECL, possibly deferring it.
4563 Every TYPE_DECL generated for a type definition must be passed
4564 to this function once everything else has been done for it. */
4566 void
4568 {
4569 /* We need to defer finalizing the type if incomplete types
4570 are being deferred or if they are being processed. */
4573 else
4575 }
4577 /* Same as above but without deferring the compilation. This
4578 function should not be invoked directly on a TYPE_DECL. */
4580 static void
4582 {
4588 /* Now process all the variants. This is needed for STABS. */
4590 {
4595 {
4598 }
4601 }
4602 }
4604 /* Finalize any From_With_Type incomplete types. We do this after processing
4605 our compilation unit and after processing its spec, if this is a body. */
4607 void
4609 {
4615 {
4622 }
4623 }
4625 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
4626 kind of type (such E_Task_Type) that has a different type which Gigi
4627 uses for its representation. If the type does not have a special type
4628 for its representation, return GNAT_ENTITY. If a type is supposed to
4629 exist, but does not, abort unless annotating types, in which case
4630 return Empty. If GNAT_ENTITY is Empty, return Empty. */
4632 Entity_Id
4634 {
4641 {
4667 }
4671 }
4673 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
4674 using MECH as its passing mechanism, to be placed in the parameter
4675 list built for GNAT_SUBPROG. Assume a foreign convention for the
4676 latter if FOREIGN is true. Also set CICO to true if the parameter
4677 must use the copy-in copy-out implementation mechanism.
4679 The returned tree is a PARM_DECL, except for those cases where no
4680 parameter needs to be actually passed to the subprogram; the type
4681 of this "shadow" parameter is then returned instead. */
4683 static tree
4686 {
4690 /* The parameter can be indirectly modified if its address is taken. */
4693 tree gnu_param;
4695 /* Copy-return is used only for the first parameter of a valued procedure.
4696 It's a copy mechanism for which a parameter is never allocated. */
4698 {
4702 }
4704 /* If this is either a foreign function or if the underlying type won't
4705 be passed by reference, strip off possible padding type. */
4708 {
4712 || foreign
4716 }
4718 /* If this is a read-only parameter, make a variant of the type that is
4719 read-only. ??? However, if this is an unconstrained array, that type
4720 can be very complex, so skip it for now. Likewise for any other
4721 self-referential type. */
4729 /* For foreign conventions, pass arrays as pointers to the element type.
4730 First check for unconstrained array and get the underlying array. */
4732 gnu_param_type
4735 /* VMS descriptors are themselves passed by reference. */
4737 gnu_param_type
4740 gnat_subprog));
4742 /* Arrays are passed as pointers to element type for foreign conventions. */
4746 {
4747 /* Strip off any multi-dimensional entries, then strip
4748 off the last array to get the component type. */
4762 }
4764 /* Fat pointers are passed as thin pointers for foreign conventions. */
4766 gnu_param_type
4769 /* If we must pass or were requested to pass by reference, do so.
4770 If we were requested to pass by copy, do so.
4771 Otherwise, for foreign conventions, pass In Out or Out parameters
4772 or aggregates by reference. For COBOL and Fortran, pass all
4773 integer and FP types that way too. For Convention Ada, use
4774 the standard Ada default. */
4778 && ((foreign
4780 || (foreign
4785 || (!foreign
4787 {
4790 }
4792 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
4799 /* If this is an Out parameter that isn't passed by reference and isn't
4800 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
4801 it will be a VAR_DECL created when we process the procedure, so just
4802 return its type. For the special parameter of a valued procedure,
4803 never pass it in.
4805 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
4806 Out parameters with discriminants or implicit initial values to be
4807 handled like In Out parameters. These type are normally built as
4808 aggregates, hence passed by reference, except for some packed arrays
4809 which end up encoded in special integer types.
4811 The exception we need to make is then for packed arrays of records
4812 with discriminants or implicit initial values. We have no light/easy
4813 way to check for the latter case, so we merely check for packed arrays
4814 of records. This may lead to useless copy-in operations, but in very
4815 rare cases only, as these would be exceptions in a set of already
4816 exceptional situations. */
4818 && !by_ref
4819 && (by_return
4836 /* If no Mechanism was specified, indicate what we're using, then
4837 back-annotate it. */
4843 }
4845 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
4847 static bool
4849 {
4856 return
4858 }
4860 /* Return true if the array type specified by GNAT_TYPE and GNU_TYPE has
4861 a non-aliased component in the back-end sense. */
4863 static bool
4865 {
4866 /* If the type below this is a multi-array type, then
4867 this does not have aliased components. */
4876 }
4877 \f
4878 /* Given GNAT_ENTITY, elaborate all expressions that are required to
4879 be elaborated at the point of its definition, but do nothing else. */
4881 void
4883 {
4885 {
4892 {
4896 /* ??? Tests for avoiding static constraint error expression
4897 is needed until the front stops generating bogus conversions
4898 on bounds of real types. */
4907 }
4910 {
4914 /* If this is a record extension, go a level further to find the
4915 record definition. */
4918 }
4928 {
4929 Node_Id gnat_discriminant_expr;
4930 Entity_Id gnat_field;
4933 gnat_discriminant_expr
4938 /* ??? For now, ignore access discriminants. */
4941 gnat_entity,
4943 }
4946 }
4947 }
4948 \f
4949 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
4950 any entities on its entity chain similarly. */
4952 void
4954 {
4955 Entity_Id gnat_sub_entity;
4958 /* If this has an entity list, process all in the list. */
4975 /* Now clear this if it has been defined, but only do so if it isn't
4976 a subprogram or parameter. We could refine this, but it isn't
4977 worth it. If this is statically allocated, it is supposed to
4978 hang around out of cope. */
4981 {
4984 }
4985 }
4986 \f
4987 /* Set the alias set of GNU_NEW_TYPE to be that of GNU_OLD_TYPE. If this
4988 is a multi-dimensional array type, do this recursively. */
4990 static void
4992 {
4993 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
4994 of a one-dimensional array, since the padding has the same alias set
4995 as the field type, but if it's a multi-dimensional array, we need to
4996 see the inner types. */
5002 /* We need to be careful here in case GNU_OLD_TYPE is an unconstrained
5003 array. In that case, it doesn't have the same shape as GNU_NEW_TYPE,
5004 so we need to go down to what does. */
5006 gnu_old_type
5016 }
5017 \f
5018 /* Return a TREE_LIST describing the substitutions needed to reflect
5019 discriminant substitutions from GNAT_SUBTYPE to GNAT_TYPE and add
5020 them to GNU_LIST. If GNAT_TYPE is not specified, use the base type
5021 of GNAT_SUBTYPE. The substitutions can be in any order. TREE_PURPOSE
5022 gives the tree for the discriminant and TREE_VALUES is the replacement
5023 value. They are in the form of operands to substitute_in_expr.
5024 DEFINITION is as in gnat_to_gnu_entity. */
5026 static tree
5029 {
5030 Entity_Id gnat_discrim;
5031 Node_Id gnat_value;
5042 /* Ignore access discriminants. */
5045 elaborate_expression
5049 gnu_list);
5052 }
5053 \f
5054 /* Return true if the size represented by GNU_SIZE can be handled by an
5055 allocation. If STATIC_P is true, consider only what can be done with a
5056 static allocation. */
5058 static bool
5060 {
5061 HOST_WIDE_INT our_size;
5063 /* If this is not a static allocation, the only case we want to forbid
5064 is an overflowing size. That will be converted into a raise a
5065 Storage_Error. */
5070 /* Otherwise, we need to deal with both variable sizes and constant
5071 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
5072 since assemblers may not like very large sizes. */
5078 }
5079 \f
5080 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
5081 NAME, ARGS and ERROR_POINT. */
5083 static void
5086 tree attr_name,
5087 tree attr_args,
5088 Node_Id attr_error_point)
5089 {
5099 }
5101 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
5103 static void
5105 {
5106 Node_Id gnat_temp;
5111 {
5120 {
5122 (gnat_to_gnu
5129 (gnat_to_gnu
5130 (Expression
5133 }
5136 {
5163 }
5166 /* Prepend to the list now. Make a list of the argument we might
5167 have, as GCC expects it. */
5168 prepend_one_attribute_to
5175 }
5176 }
5177 \f
5178 /* Get the unpadded version of a GNAT type. */
5180 tree
5182 {
5189 }
5190 \f
5191 /* Called when we need to protect a variable object using a save_expr. */
5193 tree
5195 {
5202 {
5210 }
5211 else
5213 }
5214 \f
5215 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
5216 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
5217 return the GCC tree to use for that expression. GNU_NAME is the
5218 qualification to use if an external name is appropriate and DEFINITION is
5219 nonzero if this is a definition of GNAT_ENTITY. If NEED_VALUE is nonzero,
5220 we need a result. Otherwise, we are just elaborating this for
5221 side-effects. If NEED_DEBUG is nonzero we need the symbol for debugging
5222 purposes even if it isn't needed for code generation. */
5224 static tree
5228 {
5229 tree gnu_expr;
5231 /* If we already elaborated this expression (e.g., it was involved
5232 in the definition of a private type), use the old value. */
5236 /* If we don't need a value and this is static or a discriminant, we
5237 don't need to do anything. */
5244 /* Otherwise, convert this tree to its GCC equivalent. */
5245 gnu_expr
5249 /* Save the expression in case we try to elaborate this entity again. Since
5250 this is not a DECL, don't check it. Don't save if it's a discriminant. */
5255 }
5257 /* Similar, but take a GNU expression. */
5259 static tree
5263 {
5265 /* Strip any conversions to see if the expression is a readonly variable.
5266 ??? This really should remain readonly, but we have to think about
5267 the typing of the tree here. */
5272 /* In most cases, we won't see a naked FIELD_DECL here because a
5273 discriminant reference will have been replaced with a COMPONENT_REF
5274 when the type is being elaborated. However, there are some cases
5275 involving child types where we will. So convert it to a COMPONENT_REF
5276 here. We have to hope it will be at the highest level of the
5277 expression in these cases. */
5283 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
5284 that is a constant, make a variable that is initialized to contain the
5285 bound when the package containing the definition is elaborated. If
5286 this entity is defined at top level and a bound or discriminant value
5287 isn't a constant or a reference to a discriminant, replace the bound
5288 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
5289 rely here on the fact that an expression cannot contain both the
5290 discriminant and some other variable. */
5298 /* If this is a static expression or contains a discriminant, we don't
5299 need the variable for debugging (and can't elaborate anyway if a
5300 discriminant). */
5306 /* Now create the variable if we need it. */
5308 gnu_decl
5315 /* We only need to use this variable if we are in global context since GCC
5316 can do the right thing in the local case. */
5321 else
5323 }
5324 \f
5325 /* Create a record type that contains a SIZE bytes long field of TYPE with a
5326 starting bit position so that it is aligned to ALIGN bits, and leaving at
5327 least ROOM bytes free before the field. BASE_ALIGN is the alignment the
5328 record is guaranteed to get. */
5330 tree
5333 {
5334 /* We will be crafting a record type with one field at a position set to be
5335 the next multiple of ALIGN past record'address + room bytes. We use a
5336 record placeholder to express record'address. */
5341 tree record_addr_st
5344 /* The diagram below summarizes the shape of what we manipulate:
5346 <--------- pos ---------->
5347 { +------------+-------------+-----------------+
5348 record =>{ |############| ... | field (type) |
5349 { +------------+-------------+-----------------+
5350 |<-- room -->|<- voffset ->|<---- size ----->|
5351 o o
5352 | |
5353 record_addr vblock_addr
5355 Every length is in sizetype bytes there, except "pos" which has to be
5356 set as a bit position in the GCC tree for the record. */
5369 /* Compute VOFFSET and then POS. The next byte position multiple of some
5370 alignment after some address is obtained by "and"ing the alignment minus
5371 1 with the two's complement of the address. */
5377 /* POS = (ROOM + VOFFSET) * BIT_PER_UNIT, in bitsizetype. */
5382 bitsize_unit_node);
5384 /* Craft the GCC record representation. We exceptionally do everything
5385 manually here because 1) our generic circuitry is not quite ready to
5386 handle the complex position/size expressions we are setting up, 2) we
5387 have a strong simplifying factor at hand: we know the maximum possible
5388 value of voffset, and 3) we have to set/reset at least the sizes in
5389 accordance with this maximum value anyway, as we need them to convey
5390 what should be "alloc"ated for this type.
5392 Use -1 as the 'addressable' indication for the field to prevent the
5393 creation of a bitfield. We don't need one, it would have damaging
5394 consequences on the alignment computation, and create_field_decl would
5395 make one without this special argument, for instance because of the
5396 complex position expression. */
5408 bitsize_unit_node),
5418 }
5419 \f
5420 /* Return the result of rounding T up to ALIGN. */
5424 {
5429 }
5431 /* TYPE is a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE that is being used
5432 as the field type of a packed record if IN_RECORD is true, or as the
5433 component type of a packed array if IN_RECORD is false. See if we can
5434 rewrite it either as a type that has a non-BLKmode, which we can pack
5435 tighter in the packed record case, or as a smaller type with BLKmode.
5436 If so, return the new type. If not, return the original type. */
5438 static tree
5440 {
5445 /* No point in doing anything if the size is zero. */
5451 /* Copy the name and flags from the old type to that of the new.
5452 Note that we rely on the pointer equality created here for
5453 TYPE_NAME to look through conversions in various places. */
5460 /* If we are in a record and have a small size, set the alignment to
5461 try for an integral mode. Otherwise set it to try for a smaller
5462 type with BLKmode. */
5464 {
5467 }
5468 else
5469 {
5472 /* Do not try to shrink the size if the RM size is not constant. */
5477 /* Round the RM size up to a unit boundary to get the minimal size
5478 for a BLKmode record. Give up if it's already the size. */
5486 }
5490 /* Now copy the fields, keeping the position and size as we don't want
5491 to change the layout by propagating the packedness downwards. */
5494 {
5505 /* However, for the last field in a not already packed record type
5506 that is of an aggregate type, we need to use the RM_Size in the
5507 packable version of the record type, see finish_record_type. */
5517 else
5526 SET_DECL_ORIGINAL_FIELD
5535 }
5540 /* If this is a padding record, we never want to make the size smaller
5541 than what was specified. For QUAL_UNION_TYPE, also copy the size. */
5544 {
5547 }
5548 else
5549 {
5553 }
5560 /* Try harder to get a packable type if necessary, for example
5561 in case the record itself contains a BLKmode field. */
5566 /* If neither the mode nor the size has shrunk, return the old type. */
5571 }
5572 \f
5573 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
5574 if needed. We have already verified that SIZE and TYPE are large enough.
5576 GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
5577 to issue a warning.
5579 IS_USER_TYPE is true if we must complete the original type.
5581 DEFINITION is true if this type is being defined.
5583 SAME_RM_SIZE is true if the RM_Size of the resulting type is to be set
5584 to SIZE too; otherwise, it's set to the RM_Size of the original type. */
5586 tree
5590 {
5596 /* If TYPE is a padded type, see if it agrees with any size and alignment
5597 we were given. If so, return the original type. Otherwise, strip
5598 off the padding, since we will either be returning the inner type
5599 or repadding it. If no size or alignment is specified, use that of
5600 the original padded type. */
5602 {
5619 }
5621 /* If the size is either not being changed or is being made smaller (which
5622 is not done here (and is only valid for bitfields anyway), show the size
5623 isn't changing. Likewise, clear the alignment if it isn't being
5624 changed. Then return if we aren't doing anything. */
5637 /* If requested, complete the original type and give it a name. */
5644 gnat_entity);
5646 /* We used to modify the record in place in some cases, but that could
5647 generate incorrect debugging information. So make a new record
5648 type and name. */
5666 bitsize_unit_node));
5668 /* If we are changing the alignment and the input type is a record with
5669 BLKmode and a small constant size, try to make a form that has an
5670 integral mode. This might allow the padding record to also have an
5671 integral mode, which will be much more efficient. There is no point
5672 in doing so if a size is specified unless it is also a small constant
5673 size and it is incorrect to do so if we cannot guarantee that the mode
5674 will be naturally aligned since the field must always be addressable. */
5681 && (!size
5684 {
5689 }
5691 /* Now create the field with the original size. */
5696 /* Do not finalize it until after the auxiliary record is built. */
5699 /* Set the same size for its RM_size if requested; otherwise reuse
5700 the RM_size of the original type. */
5703 /* Unless debugging information isn't being written for the input type,
5704 write a record that shows what we are a subtype of and also make a
5705 variable that indicates our size, if still variable. */
5711 {
5733 }
5737 /* If the size was widened explicitly, maybe give a warning. Take the
5738 original size as the maximum size of the input if there was an
5739 unconstrained record involved and round it up to the specified alignment,
5740 if one was specified. */
5752 {
5765 /* Generate message only for entities that come from source, since
5766 if we have an entity created by expansion, the message will be
5767 generated for some other corresponding source entity. */
5770 gnat_entity,
5777 }
5780 }
5781 \f
5782 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
5783 the value passed against the list of choices. */
5785 tree
5787 {
5788 Node_Id choice;
5789 Node_Id gnat_temp;
5794 {
5796 {
5801 /* There's no good type to use here, so we might as well use
5802 integer_type_node. */
5803 this_test
5817 this_test
5827 /* This represents either a subtype range, an enumeration
5828 literal, or a constant Ekind says which. If an enumeration
5829 literal or constant, fall through to the next case. */
5832 {
5838 this_test
5845 }
5846 /* ... fall through ... */
5851 single);
5860 }
5864 }
5867 }
5868 \f
5869 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
5870 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
5872 static int
5874 {
5875 /* If the field contains an item of variable size, we cannot pack it
5876 because we cannot create temporaries of non-fixed size in case
5877 we need to take the address of the field. See addressable_p and
5878 the notes on the addressability issues for further details. */
5882 /* If the alignment of the record is specified and the field type
5883 is over-aligned, request Storage_Unit alignment for the field. */
5885 {
5888 else
5890 }
5893 }
5895 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
5896 placed in GNU_RECORD_TYPE.
5898 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
5899 record has Component_Alignment of Storage_Unit, -2 if the enclosing
5900 record has a specified alignment.
5902 DEFINITION is true if this field is for a record being defined. */
5904 static tree
5907 {
5911 bool needs_strict_alignment
5915 /* If this field requires strict alignment, we cannot pack it because
5916 it would very likely be under-aligned in the record. */
5919 else
5922 /* If a size is specified, use it. Otherwise, if the record type is packed,
5923 use the official RM size. See "Handling of Type'Size Values" in Einfo
5924 for further details. */
5931 else
5934 /* If we have a specified size that's smaller than that of the field type,
5935 or a position is specified, and the field type is also a record that's
5936 BLKmode, see if we can get either an integral mode form of the type or
5937 a smaller BLKmode form. If we can, show a size was specified for the
5938 field if there wasn't one already, so we know to make this a bitfield
5939 and avoid making things wider.
5941 Doing this is first useful if the record is packed because we may then
5942 place the field at a non-byte-aligned position and so achieve tighter
5943 packing.
5945 This is in addition *required* if the field shares a byte with another
5946 field and the front-end lets the back-end handle the references, because
5947 GCC does not handle BLKmode bitfields properly.
5949 We avoid the transformation if it is not required or potentially useful,
5950 as it might entail an increase of the field's alignment and have ripple
5951 effects on the outer record type. A typical case is a field known to be
5952 byte aligned and not to share a byte with another field.
5954 Besides, we don't even look the possibility of a transformation in cases
5955 known to be in error already, for instance when an invalid size results
5956 from a component clause. */
5962 || (gnu_size
5965 {
5966 /* See what the alternate type and size would be. */
5969 bool has_byte_aligned_clause
5974 /* Compute whether we should avoid the substitution. */
5975 bool reject
5976 /* There is no point substituting if there is no change... */
5978 /* ... nor when the field is known to be byte aligned and not to
5979 share a byte with another field. */
5980 || (has_byte_aligned_clause
5982 /* The size of an aliased field must be an exact multiple of the
5983 type's alignment, which the substitution might increase. Reject
5984 substitutions that would so invalidate a component clause when the
5985 specified position is byte aligned, as the change would have no
5986 real benefit from the packing standpoint anyway. */
5988 && has_byte_aligned_clause
5991 /* Substitute unless told otherwise. */
5993 {
5998 }
5999 }
6001 /* If we are packing the record and the field is BLKmode, round the
6002 size up to a byte boundary. */
6007 {
6012 /* Ensure the position does not overlap with the parent subtype,
6013 if there is one. */
6015 {
6016 tree gnu_parent
6022 {
6023 post_error_ne_tree
6027 }
6028 }
6030 /* If this field needs strict alignment, ensure the record is
6031 sufficiently aligned and that that position and size are
6032 consistent with the alignment. */
6034 {
6040 {
6042 post_error_ne_tree
6048 post_error_ne_tree
6054 post_error_ne_tree
6060 }
6065 {
6067 post_error_ne_num
6073 post_error_ne_num
6079 post_error_ne_num
6084 else
6088 }
6089 }
6093 }
6095 /* If the record has rep clauses and this is the tag field, make a rep
6096 clause for it as well. */
6099 {
6102 }
6104 else
6107 /* We need to make the size the maximum for the type if it is
6108 self-referential and an unconstrained type. In that case, we can't
6109 pack the field since we can't make a copy to align it. */
6111 && !gnu_size
6114 {
6117 }
6119 /* If a size is specified, adjust the field's type to it. */
6121 {
6122 /* If the field's type is justified modular, we would need to remove
6123 the wrapper to (better) meet the layout requirements. However we
6124 can do so only if the field is not aliased to preserve the unique
6125 layout and if the prescribed size is not greater than that of the
6126 packed array to preserve the justification. */
6134 gnu_field_type
6139 }
6141 /* Otherwise (or if there was an error), don't specify a position. */
6142 else
6148 /* Now create the decl for the field. */
6160 }
6161 \f
6162 /* Return true if TYPE is a type with variable size, a padding type with a
6163 field of variable size or is a record that has a field such a field. */
6165 static bool
6167 {
6168 tree field;
6188 }
6189 \f
6190 /* qsort comparer for the bit positions of two record components. */
6192 static int
6194 {
6197 const int ret
6201 }
6203 /* Return a GCC tree for a record type given a GNAT Component_List and a chain
6204 of GCC trees for fields that are in the record and have already been
6205 processed. When called from gnat_to_gnu_entity during the processing of a
6206 record type definition, the GCC nodes for the discriminants will be on
6207 the chain. The other calls to this function are recursive calls from
6208 itself for the Component_List of a variant and the chain is empty.
6210 PACKED is 1 if this is for a packed record, -1 if this is for a record
6211 with Component_Alignment of Storage_Unit, -2 if this is for a record
6212 with a specified alignment.
6214 DEFINITION is true if we are defining this record.
6216 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
6217 with a rep clause is to be added. If it is nonzero, that is all that
6218 should be done with such fields.
6220 CANCEL_ALIGNMENT, if true, means the alignment should be zeroed before
6221 laying out the record. This means the alignment only serves to force fields
6222 to be bitfields, but not require the record to be that aligned. This is
6223 used for variants.
6225 ALL_REP, if true, means a rep clause was found for all the fields. This
6226 simplifies the logic since we know we're not in the mixed case.
6228 DO_NOT_FINALIZE, if true, means that the record type is expected to be
6229 modified afterwards so it will not be sent to the back-end for finalization.
6231 UNCHECKED_UNION, if true, means that we are building a type for a record
6232 with a Pragma Unchecked_Union.
6234 The processing of the component list fills in the chain with all of the
6235 fields of the record and then the record type is finished. */
6237 static void
6242 {
6243 Node_Id component_decl;
6244 Entity_Id gnat_field;
6245 Node_Id variant_part;
6251 /* For each variable within each component declaration create a GCC field
6252 and add it to the list, skipping any pragmas in the list. */
6257 {
6262 else
6263 {
6267 /* If this is the _Tag field, put it before any discriminants,
6268 instead of after them as is the case for all other fields.
6269 Ignore field of void type if only annotating. */
6272 else
6273 {
6276 }
6277 }
6280 }
6282 /* At the end of the component list there may be a variant part. */
6285 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
6286 mutually exclusive and should go in the same memory. To do this we need
6287 to treat each variant as a record whose elements are created from the
6288 component list for the variant. So here we create the records from the
6289 lists for the variants and put them all into the QUAL_UNION_TYPE.
6290 If this is an Unchecked_Union, we make a UNION_TYPE instead or
6291 use GNU_RECORD_TYPE if there are no fields so far. */
6293 {
6295 Node_Id variant;
6297 tree gnu_var_name
6301 tree gnu_union_type;
6302 tree gnu_union_name;
6303 tree gnu_union_field;
6312 /* Reuse an enclosing union if all fields are in the variant part
6313 and there is no representation clause on the record, to match
6314 the layout of C unions. There is an associated check below. */
6319 else
6320 {
6321 gnu_union_type
6326 }
6331 {
6333 tree gnu_inner_name;
6334 tree gnu_qual;
6342 /* Set the alignment of the inner type in case we need to make
6343 inner objects into bitfields, but then clear it out
6344 so the record actually gets only the alignment required. */
6348 /* Similarly, if the outer record has a size specified and all fields
6349 have record rep clauses, we can propagate the size into the
6350 variant part. */
6352 {
6356 }
6358 /* Create the record type for the variant. Note that we defer
6359 finalizing it until after we are sure to actually use it. */
6370 /* If this is an Unchecked_Union and we have exactly one field,
6371 use this field directly to match the layout of C unions. */
6376 else
6377 {
6378 /* Deal with packedness like in gnat_to_gnu_field. */
6379 int field_packed
6382 /* Finalize the record type now. We used to throw away
6383 empty records but we no longer do that because we need
6384 them to generate complete debug info for the variant;
6385 otherwise, the union type definition will be lacking
6386 the fields associated with these empty variants. */
6391 (all_rep_and_size
6394 (all_rep_and_size
6402 }
6406 }
6408 /* Only make the QUAL_UNION_TYPE if there are any non-empty variants. */
6410 {
6412 {
6416 }
6421 /* If GNU_UNION_TYPE is our record type, it means we must have an
6422 Unchecked_Union with no fields. Verify that and, if so, just
6423 return. */
6425 {
6427 && !gnu_field_list
6430 }
6432 gnu_union_field
6434 packed,
6441 }
6442 }
6444 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
6445 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do this
6446 in a separate pass since we want to handle the discriminants but can't
6447 play with them until we've used them in debugging data above.
6449 ??? Note: if we then reorder them, debugging information will be wrong,
6450 but there's nothing that can be done about this at the moment. */
6452 {
6454 {
6459 else
6465 }
6466 else
6467 {
6470 }
6471 }
6473 /* If we have any items in our rep'ed field list, it is not the case that all
6474 the fields in the record have rep clauses, and P_REP_LIST is nonzero,
6475 set it and ignore the items. */
6479 {
6480 /* Otherwise, sort the fields by bit position and put them into their
6481 own record if we have any fields without rep clauses. */
6482 tree gnu_rep_type
6494 /* Put the fields in the list in order of increasing position, which
6495 means we start from the end. */
6498 {
6502 }
6505 {
6511 }
6512 else
6513 {
6516 }
6517 }
6524 }
6525 \f
6526 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
6527 placed into an Esize, Component_Bit_Offset, or Component_Size value
6528 in the GNAT tree. */
6530 static Uint
6532 {
6534 TCode tcode;
6540 /* See if we've already saved the value for this node. */
6542 {
6553 }
6555 /* If we do not return inside this switch, TCODE will be set to the
6556 code to use for a Create_Node operand and LEN (set above) will be
6557 the number of recursive calls for us to make. */
6560 {
6565 /* This may have come from a conversion from some smaller type,
6566 so ensure this is in bitsizetype. */
6569 /* For negative values, use NEGATE_EXPR of the supplied value. */
6571 {
6572 /* The ridiculous code below is to handle the case of the largest
6573 negative integer. */
6576 tree temp;
6579 {
6580 negative_size
6583 bitsize_one_node));
6585 }
6592 }
6599 /* This peculiar test is to make sure that the size fits in an int
6600 on machines where HOST_WIDE_INT is not "int". */
6603 else
6607 /* The only case we handle here is a simple discriminant reference. */
6615 else
6621 /* Now just list the operations we handle. */
6653 }
6655 /* Now get each of the operands that's relevant for this code. If any
6656 cannot be expressed as a repinfo node, say we can't. */
6661 {
6665 }
6669 /* Save the result in the cache. */
6671 {
6675 }
6678 }
6680 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding
6681 GCC type, set Component_Bit_Offset and Esize to the position and size
6682 used by Gigi. */
6684 static void
6686 {
6687 tree gnu_list;
6688 tree gnu_entry;
6689 Entity_Id gnat_field;
6691 /* We operate by first making a list of all fields and their positions
6692 (we can get the sizes easily at any time) by a recursive call
6693 and then update all the sizes into the tree. */
6696 BIGGEST_ALIGNMENT);
6703 {
6707 gnu_list);
6710 {
6712 {
6713 /* In this mode the tag and parent components have not been
6714 generated, so we add the appropriate offset to each
6715 component. For a component appearing in the current
6716 extension, the offset is the size of the parent. */
6719 parent_offset
6721 bitsizetype);
6722 else
6724 }
6726 Set_Component_Bit_Offset
6728 annotate_value
6733 parent_offset)));
6737 }
6740 {
6741 /* If there is no gnu_entry, this is an inherited component whose
6742 position is the same as in the parent type. */
6743 Set_Component_Bit_Offset
6748 }
6749 }
6750 }
6752 /* Scan all fields in GNU_TYPE and build entries where TREE_PURPOSE is the
6753 FIELD_DECL and TREE_VALUE a TREE_LIST with TREE_PURPOSE being the byte
6754 position and TREE_VALUE being a TREE_LIST with TREE_PURPOSE the value to be
6755 placed into DECL_OFFSET_ALIGN and TREE_VALUE the bit position. GNU_POS is
6756 to be added to the position, GNU_BITPOS to the bit position, OFFSET_ALIGN is
6757 the present value of DECL_OFFSET_ALIGN and GNU_LIST is a list of the entries
6758 so far. */
6760 static tree
6763 {
6764 tree gnu_field;
6769 {
6774 unsigned int our_offset_align
6777 gnu_result
6782 NULL_TREE),
6783 gnu_result);
6786 gnu_result
6789 our_offset_align);
6790 }
6793 }
6794 \f
6795 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
6796 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
6797 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
6798 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
6799 for the size of a field. COMPONENT_P is true if we are being called
6800 to process the Component_Size of GNAT_OBJECT. This is used for error
6801 message handling and to indicate to use the object size of GNU_TYPE.
6802 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
6803 it means that a size of zero should be treated as an unspecified size. */
6805 static tree
6808 {
6809 Node_Id gnat_error_node;
6813 /* If a type needs strict alignment, a component of this type in
6814 a packed record cannot be packed and thus uses the type size. */
6817 else
6820 /* Find the node to use for errors. */
6827 else
6830 /* Return 0 if no size was specified, either because Esize was not Present or
6831 the specified size was zero. */
6835 /* Get the size as a tree. Give an error if a size was specified, but cannot
6836 be represented as in sizetype. */
6839 {
6844 }
6846 /* Ignore a negative size since that corresponds to our back-annotation.
6847 Also ignore a zero size unless a size clause exists. */
6851 /* The size of objects is always a multiple of a byte. */
6854 {
6858 else
6862 }
6864 /* If this is an integral type or a packed array type, the front-end has
6865 verified the size, so we need not do it here (which would entail
6866 checking against the bounds). However, if this is an aliased object, it
6867 may not be smaller than the type of the object. */
6872 /* If the object is a record that contains a template, add the size of
6873 the template to the specified size. */
6878 /* Modify the size of the type to be that of the maximum size if it has a
6879 discriminant. */
6883 /* If this is an access type or a fat pointer, the minimum size is that given
6884 by the smallest integral mode that's valid for pointers. */
6886 {
6892 ;
6895 }
6897 /* If the size of the object is a constant, the new size must not be
6898 smaller. */
6902 {
6904 post_error_ne_tree
6907 else
6914 post_error_ne_tree_2
6924 }
6927 }
6928 \f
6929 /* Similarly, but both validate and process a value of RM_Size. This
6930 routine is only called for types. */
6932 static void
6934 {
6935 /* Only give an error if a Value_Size clause was explicitly given.
6936 Otherwise, we'd be duplicating an error on the Size clause. */
6937 Node_Id gnat_attr_node
6940 tree size;
6942 /* Get the size as a tree. Do nothing if none was specified, either
6943 because RM_Size was not Present or if the specified size was zero.
6944 Give an error if a size was specified, but cannot be represented as
6945 in sizetype. */
6951 {
6954 gnat_entity);
6957 }
6959 /* Ignore a negative size since that corresponds to our back-annotation.
6960 Also ignore a zero size unless a size clause exists, a Value_Size
6961 clause exists, or this is an integer type, in which case the
6962 front end will have always set it. */
6969 /* If the old size is self-referential, get the maximum size. */
6973 /* If the size of the object is a constant, the new size must not be
6974 smaller (the front end checks this for scalar types). */
6979 {
6981 post_error_ne_tree
6986 }
6988 /* Otherwise, set the RM_Size. */
6999 }
7000 \f
7001 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
7002 If TYPE is the best type, return it. Otherwise, make a new type. We
7003 only support new integral and pointer types. BIASED_P is nonzero if
7004 we are making a biased type. */
7006 static tree
7008 {
7009 tree new_type;
7013 /* If size indicates an error, just return TYPE to avoid propagating the
7014 error. Likewise if it's too large to represent. */
7020 {
7023 /* Only do something if the type is not already the proper size and is
7024 not a packed array type. */
7036 new_type
7048 /* Do something if this is a fat pointer, in which case we
7049 may need to return the thin pointer. */
7051 return
7052 build_pointer_type
7057 /* Only do something if this is a thin pointer, in which case we
7058 may need to return the fat pointer. */
7060 return
7067 }
7070 }
7071 \f
7072 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
7073 a type or object whose present alignment is ALIGN. If this alignment is
7074 valid, return it. Otherwise, give an error and return ALIGN. */
7076 static unsigned int
7078 {
7081 Node_Id gnat_error_node;
7083 /* Don't worry about checking alignment if alignment was not specified
7084 by the source program and we already posted an error for this entity. */
7088 /* Post the error on the alignment clause if any. */
7091 else
7094 /* Within GCC, an alignment is an integer, so we must make sure a value is
7095 specified that fits in that range. Also, there is an upper bound to
7096 alignments we can support/allow. */
7107 else
7108 {
7112 }
7115 }
7117 /* Return the smallest alignment not less than SIZE. */
7119 static unsigned int
7121 {
7123 }
7124 \f
7125 /* Verify that OBJECT, a type or decl, is something we can implement
7126 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
7127 if we require atomic components. */
7129 static void
7131 {
7133 Node_Id gnat_node;
7136 tree size;
7138 /* There are three case of what OBJECT can be. It can be a type, in which
7139 case we take the size, alignment and mode from the type. It can be a
7140 declaration that was indirect, in which case the relevant values are
7141 that of the type being pointed to, or it can be a normal declaration,
7142 in which case the values are of the decl. The code below assumes that
7143 OBJECT is either a type or a decl. */
7145 {
7149 }
7151 {
7155 }
7156 else
7157 {
7161 }
7163 /* Consider all floating-point types atomic and any types that that are
7164 represented by integers no wider than a machine word. */
7171 /* For the moment, also allow anything that has an alignment equal
7172 to its size and which is smaller than a word. */
7180 {
7189 }
7194 else
7197 }
7198 \f
7199 /* Check if FTYPE1 and FTYPE2, two potentially different function type nodes,
7200 have compatible signatures so that a call using one type may be safely
7201 issued if the actual target function type is the other. Return 1 if it is
7202 the case, 0 otherwise, and post errors on the incompatibilities.
7204 This is used when an Ada subprogram is mapped onto a GCC builtin, to ensure
7205 that calls to the subprogram will have arguments suitable for the later
7206 underlying builtin expansion. */
7208 static int
7210 {
7211 /* As of now, we only perform very trivial tests and consider it's the
7212 programmer's responsibility to ensure the type correctness in the Ada
7213 declaration, as in the regular Import cases.
7215 Mismatches typically result in either error messages from the builtin
7216 expander, internal compiler errors, or in a real call sequence. This
7217 should be refined to issue diagnostics helping error detection and
7218 correction. */
7220 /* Almost fake test, ensuring a use of each argument. */
7225 }
7226 \f
7227 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new
7228 type with all size expressions that contain F updated by replacing F
7229 with R. If F is NULL_TREE, always make a new RECORD_TYPE, even if
7230 nothing has changed. */
7232 tree
7234 {
7236 tree tem;
7239 {
7245 {
7254 SET_TYPE_INDEX_TYPE
7257 }
7264 {
7278 }
7292 /* Don't know how to do these yet. */
7296 {
7311 /* If we had bounded the sizes of T by a constant, bound the sizes of
7312 NEW by the same constant. */
7322 }
7327 {
7328 tree field;
7329 bool changed_field
7336 /* Start out with no fields, make new fields, and chain them
7337 in. If we haven't actually changed the type of any field,
7338 discard everything we've done and return the old type. */
7344 {
7355 /* If this is an internal field and the type of this field is
7356 a UNION_TYPE or RECORD_TYPE with no elements, ignore it. If
7357 the type just has one element, treat that as the field.
7358 But don't do this if we are processing a QUAL_UNION_TYPE. */
7363 {
7368 {
7369 tree next_new_field
7372 /* Make sure omitting the union doesn't change
7373 the layout. */
7376 }
7377 }
7384 /* If the size of the old field was set at a constant,
7385 propagate the size in case the type's size was variable.
7386 (This occurs in the case of a variant or discriminated
7387 record with a default size used as a field of another
7388 record.) */
7397 {
7403 /* Do the substitution inside the qualifier and if we find
7404 that this field will not be present, omit it. */
7409 }
7413 else
7418 /* If this is a qualified type and this field will always be
7419 present, we are done. */
7423 }
7425 /* If this used to be a qualified union type, but we now know what
7426 field will be present, make this a normal union. */
7437 /* If the size was originally a constant use it. */
7440 {
7444 }
7447 }
7451 }
7452 }
7453 \f
7454 /* Return the "RM size" of GNU_TYPE. This is the actual number of bits
7455 needed to represent the object. */
7457 tree
7459 {
7460 /* For integer types, this is the precision. For record types, we store
7461 the size explicitly. For other types, this is just the size. */
7467 /* Return the rm_size of the actual data plus the size of the template. */
7468 return
7478 else
7480 }
7481 \f
7482 /* Return an identifier representing the external name to be used for
7483 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
7484 and the specified suffix. */
7486 tree
7488 {
7497 /* A variable using the Stdcall convention (meaning we are running
7498 on a Windows box) live in a DLL. Here we adjust its name to use
7499 the jump-table, the _imp__NAME contains the address for the NAME
7500 variable. */
7503 {
7510 }
7513 }
7515 /* Return the name to be used for GNAT_ENTITY. If a type, create a
7516 fully-qualified name, possibly with type information encoding.
7517 Otherwise, return the name. */
7519 tree
7521 {
7524 }
7526 /* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
7527 string, return a new IDENTIFIER_NODE that is the concatenation of
7528 the name in GNU_ID and SUFFIX. */
7530 tree
7532 {
7540 }