| blob | 3dbed7e51ac54d6ec8902eb9c3d60f27a565b346 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2015, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License along with GCC; see the file COPYING3. If not see *
19 * <http://www.gnu.org/licenses/>. *
20 * *
21 * GNAT was originally developed by the GNAT team at New York University. *
22 * Extensive contributions were provided by Ada Core Technologies Inc. *
23 * *
24 ****************************************************************************/
66 /* "stdcall" and "thiscall" conventions should be processed in a specific way
67 on 32-bit x86/Windows only. The macros below are helpers to avoid having
68 to check for a Windows specific attribute throughout this unit. */
70 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
71 #ifdef TARGET_64BIT
72 #define Has_Stdcall_Convention(E) \
73 (!TARGET_64BIT && Convention (E) == Convention_Stdcall)
74 #define Has_Thiscall_Convention(E) \
75 (!TARGET_64BIT && is_cplusplus_method (E))
76 #else
77 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
78 #define Has_Thiscall_Convention(E) (is_cplusplus_method (E))
79 #endif
80 #else
81 #define Has_Stdcall_Convention(E) 0
82 #define Has_Thiscall_Convention(E) 0
83 #endif
87 /* Stack realignment is necessary for functions with foreign conventions when
88 the ABI doesn't mandate as much as what the compiler assumes - that is, up
89 to PREFERRED_STACK_BOUNDARY.
91 Such realignment can be requested with a dedicated function type attribute
92 on the targets that support it. We define FOREIGN_FORCE_REALIGN_STACK to
93 characterize the situations where the attribute should be set. We rely on
94 compiler configuration settings for 'main' to decide. */
96 #ifdef MAIN_STACK_BOUNDARY
97 #define FOREIGN_FORCE_REALIGN_STACK \
98 (MAIN_STACK_BOUNDARY < PREFERRED_STACK_BOUNDARY)
99 #else
100 #define FOREIGN_FORCE_REALIGN_STACK 0
101 #endif
103 struct incomplete
104 {
106 tree old_type;
107 Entity_Id full_type;
108 };
110 /* These variables are used to defer recursively expanding incomplete types
111 while we are processing an array, a record or a subprogram type. */
115 /* This variable is used to delay expanding From_Limited_With types until the
116 end of the spec. */
120 tree discriminant;
121 tree replacement;
126 /* The type of the variant. */
127 tree type;
129 /* The associated field. */
130 tree field;
132 /* The value of the qualifier. */
133 tree qual;
135 /* The type of the variant after transformation. */
136 tree new_type;
140 /* A hash table used to cache the result of annotate_value. */
143 {
146 {
148 }
152 {
154 }
156 static void
158 {
164 else
166 }
167 };
215 /* The relevant constituents of a subprogram binding to a GCC builtin. Used
216 to pass around calls performing profile compatibility checks. */
225 \f
226 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
227 entity, return the equivalent GCC tree for that entity (a ..._DECL node)
228 and associate the ..._DECL node with the input GNAT defining identifier.
230 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
231 initial value (in GCC tree form). This is optional for a variable. For
232 a renamed entity, GNU_EXPR gives the object being renamed.
234 DEFINITION is nonzero if this call is intended for a definition. This is
235 used for separate compilation where it is necessary to know whether an
236 external declaration or a definition must be created if the GCC equivalent
237 was not created previously. The value of 1 is normally used for a nonzero
238 DEFINITION, but a value of 2 is used in special circumstances, defined in
239 the code. */
241 tree
243 {
244 /* Contains the kind of the input GNAT node. */
246 /* True if this is a type. */
248 /* True if debug info is requested for this entity. */
250 /* True if this entity is to be considered as imported. */
251 const bool imported_p
253 /* For a type, contains the equivalent GNAT node to be used in gigi. */
255 /* Temporary used to walk the GNAT tree. */
256 Entity_Id gnat_temp;
257 /* Contains the GCC DECL node which is equivalent to the input GNAT node.
258 This node will be associated with the GNAT node by calling at the end
259 of the `switch' statement. */
261 /* Contains the GCC type to be used for the GCC node. */
263 /* Contains the GCC size tree to be used for the GCC node. */
265 /* Contains the GCC name to be used for the GCC node. */
266 tree gnu_entity_name;
267 /* True if we have already saved gnu_decl as a GNAT association. */
269 /* True if we incremented defer_incomplete_level. */
271 /* True if we incremented force_global. */
273 /* True if we should check to see if elaborated during processing. */
275 /* True if we made GNU_DECL and its type here. */
277 /* Size and alignment of the GCC node, if meaningful. */
279 /* Contains the list of attributes directly attached to the entity. */
282 /* Since a use of an Itype is a definition, process it as such if it
283 is not in a with'ed unit. */
285 && is_type
289 {
290 /* Ensure that we are in a subprogram mentioned in the Scope chain of
291 this entity, our current scope is global, or we encountered a task
292 or entry (where we can't currently accurately check scoping). */
295 {
298 }
303 {
308 gnat_temp
320 && (current_function_decl
322 {
325 }
326 }
328 /* This abort means the Itype has an incorrect scope, i.e. that its
329 scope does not correspond to the subprogram it is declared in. */
331 }
333 /* If we've already processed this entity, return what we got last time.
334 If we are defining the node, we should not have already processed it.
335 In that case, we will abort below when we try to save a new GCC tree
336 for this object. We also need to handle the case of getting a dummy
337 type when a Full_View exists but be careful so as not to trigger its
338 premature elaboration. */
341 {
350 {
351 gnu_decl
355 }
358 }
360 /* If this is a numeric or enumeral type, or an access type, a nonzero Esize
361 must be specified unless it was specified by the programmer. Exceptions
362 are for access-to-protected-subprogram types and all access subtypes, as
363 another GNAT type is used to lay out the GCC type for them. */
374 /* The RM size must be specified for all discrete and fixed-point types. */
378 /* If we get here, it means we have not yet done anything with this entity.
379 If we are not defining it, it must be a type or an entity that is defined
380 elsewhere or externally, otherwise we should have defined it already. */
382 || type_annotate_only
383 || is_type
390 /* Get the name of the entity and set up the line number and filename of
391 the original definition for use in any decl we make. Make sure we do not
392 inherit another source location. */
398 /* For cases when we are not defining (i.e., we are referencing from
399 another compilation unit) public entities, show we are at global level
400 for the purpose of computing scopes. Don't do this for components or
401 discriminants since the relevant test is whether or not the record is
402 being defined. */
410 /* Handle any attributes directly attached to the entity. */
414 /* Do some common processing for types. */
416 {
417 /* Compute the equivalent type to be used in gigi. */
420 /* Machine_Attributes on types are expected to be propagated to
421 subtypes. The corresponding Gigi_Rep_Items are only attached
422 to the first subtype though, so we handle the propagation here. */
429 /* Compute a default value for the size of an elementary type. */
431 {
441 else
446 }
447 }
450 {
452 /* If this is a use of a deferred constant without address clause,
453 get its full definition. */
457 {
458 gnu_decl
462 }
464 /* If we have an external constant that we are not defining, get the
465 expression that is was defined to represent. We may throw it away
466 later if it is not a constant. But do not retrieve the expression
467 if it is an allocator because the designated type might be dummy
468 at this point. */
474 {
478 /* The expression may contain N_Expression_With_Actions nodes and
479 thus object declarations from other units. In this case, even
480 though the expression will eventually be discarded since not a
481 constant, the declarations would be stuck either in the global
482 varpool or in the current scope. Therefore we force the local
483 context and create a fake scope that we'll zap at the end. */
485 {
488 }
498 }
500 /* Ignore deferred constant definitions without address clause since
501 they are processed fully in the front-end. If No_Initialization
502 is set, this is not a deferred constant but a constant whose value
503 is built manually. And constants that are renamings are handled
504 like variables. */
506 && !gnu_expr
510 {
514 }
516 /* Ignore constant definitions already marked with the error node. See
517 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
519 && gnu_expr
522 {
525 }
534 {
535 /* The GNAT record where the component was defined. */
538 /* If the entity is a discriminant of an extended tagged type used to
539 rename a discriminant of the parent type, return the latter. */
542 {
543 gnu_decl
548 }
550 /* If the entity is an inherited component (in the case of extended
551 tagged record types), just return the original entity, which must
552 be a FIELD_DECL. Likewise for discriminants. If the entity is a
553 non-girder discriminant (in the case of derived untagged record
554 types), return the stored discriminant it renames. */
557 {
558 gnu_decl
563 }
565 /* Otherwise, if we are not defining this and we have no GCC type
566 for the containing record, make one for it. Then we should
567 have made our own equivalent. */
569 {
570 /* ??? If this is in a record whose scope is a protected
571 type and we have an Original_Record_Component, use it.
572 This is a workaround for major problems in protected type
573 handling. */
577 {
578 gnu_decl
584 }
590 }
592 else
593 /* Here we have no GCC type and this is a reference rather than a
594 definition. This should never happen. Most likely the cause is
595 reference before declaration in the GNAT tree for gnat_entity. */
597 }
603 /* Simple variables, loop variables, Out parameters and exceptions. */
604 object:
605 {
606 /* Always create a variable for volatile objects and variables seen
607 constant but with a Linker_Section pragma. */
608 bool const_flag
625 tree gnu_object_size;
628 {
632 else
634 }
636 /* Get the type after elaborating the renamed object. */
639 /* If this is a standard exception definition, then use the standard
640 exception type. This is necessary to make sure that imported and
641 exported views of exceptions are properly merged in LTO mode. */
646 /* For a debug renaming declaration, build a debug-only entity. */
648 {
649 /* Force a non-null value to make sure the symbol is retained. */
653 integer_minus_one_node));
660 }
662 /* If this is a loop variable, its type should be the base type.
663 This is because the code for processing a loop determines whether
664 a normal loop end test can be done by comparing the bounds of the
665 loop against those of the base type, which is presumed to be the
666 size used for computation. But this is not correct when the size
667 of the subtype is smaller than the type. */
671 /* Reject non-renamed objects whose type is an unconstrained array or
672 any object whose type is a dummy type or void. */
677 {
680 force_global--;
682 }
684 /* If an alignment is specified, use it if valid. Note that exceptions
685 are objects but don't have an alignment. We must do this before we
686 validate the size, since the alignment can affect the size. */
688 {
694 /* No point in changing the type if there is an address clause
695 as the final type of the object will be a reference type. */
698 else
699 {
702 gnu_type
706 /* If a padding record was made, declare it now since it will
707 never be declared otherwise. This is necessary to ensure
708 that its subtrees are properly marked. */
712 }
713 }
715 /* If we are defining the object, see if it has a Size and validate it
716 if so. If we are not defining the object and a Size clause applies,
717 simply retrieve the value. We don't want to ignore the clause and
718 it is expected to have been validated already. Then get the new
719 type, if any. */
728 {
729 gnu_type
735 }
737 /* If this object has self-referential size, it must be a record with
738 a default discriminant. We are supposed to allocate an object of
739 the maximum size in this case, unless it is a constant with an
740 initializing expression, in which case we can get the size from
741 that. Note that the resulting size may still be a variable, so
742 this may end up with an indirect allocation. */
745 {
747 {
750 {
751 /* If the initializing expression is itself a constant,
752 despite having a nominal type with self-referential
753 size, we can get the size directly from it. */
755 && TYPE_IS_PADDING_P
759 || DECL_READONLY_ONCE_ELAB
762 else
763 gnu_size
765 }
766 else
768 }
769 /* We may have no GNU_EXPR because No_Initialization is
770 set even though there's an Expression. */
775 gnu_size
777 (Etype
779 else
780 {
783 }
785 /* If we are at global level and the size isn't constant, call
786 elaborate_expression_1 to make a variable for it rather than
787 calculating it each time. */
792 }
794 /* If the size is zero byte, make it one byte since some linkers have
795 troubles with zero-sized objects. If the object will have a
796 template, that will make it nonzero so don't bother. Also avoid
797 doing that for an object renaming or an object with an address
798 clause, as we would lose useful information on the view size
799 (e.g. for null array slices) and we are not allocating the object
800 here anyway. */
812 /* If this is an object with no specified size and alignment, and
813 if either it is atomic or we are not optimizing alignment for
814 space and it is composite and not an exception, an Out parameter
815 or a reference to another object, and the size of its type is a
816 constant, set the alignment to the smallest one which is not
817 smaller than the size, with an appropriate cap. */
826 && !imported_p
830 {
833 /* No point in promoting the alignment if this doesn't prevent
834 BLKmode access to the object, in particular block copy, as
835 this will for example disable the NRV optimization for it.
836 No point in jumping through all the hoops needed in order
837 to support BIGGEST_ALIGNMENT if we don't really have to.
838 So we cap to the smallest alignment that corresponds to
839 a known efficient memory access pattern of the target. */
841 {
844 }
845 else
846 {
849 }
856 else
859 /* But make sure not to under-align the object. */
863 /* And honor the minimum valid atomic alignment, if any. */
864 #ifdef MINIMUM_ATOMIC_ALIGNMENT
867 #endif
868 }
870 /* If the object is set to have atomic components, find the component
871 type and validate it.
873 ??? Note that we ignore Has_Volatile_Components on objects; it's
874 not at all clear what to do in that case. */
876 {
885 }
887 /* Now check if the type of the object allows atomic access. Note
888 that we must test the type, even if this object has size and
889 alignment to allow such access, because we will be going inside
890 the padded record to assign to the object. We could fix this by
891 always copying via an intermediate value, but it's not clear it's
892 worth the effort. */
896 /* If this is an aliased object with an unconstrained nominal subtype,
897 make a type that includes the template. */
901 {
902 tree gnu_array
904 gnu_type
906 gnu_type,
909 debug_info_p);
910 }
912 /* ??? If this is an object of CW type initialized to a value, try to
913 ensure that the object is sufficient aligned for this value, but
914 without pessimizing the allocation. This is a kludge necessary
915 because we don't support dynamic alignment. */
922 #ifdef MINIMUM_ATOMIC_ALIGNMENT
923 /* If the size is a constant and no alignment is specified, force
924 the alignment to be the minimum valid atomic alignment. The
925 restriction on constant size avoids problems with variable-size
926 temporaries; if the size is variable, there's no issue with
927 atomic access. Also don't do this for a constant, since it isn't
928 necessary and can interfere with constant replacement. Finally,
929 do not do it for Out parameters since that creates an
930 size inconsistency with In parameters. */
940 #endif
942 /* Make a new type with the desired size and alignment, if needed.
943 But do not take into account alignment promotions to compute the
944 size of the object. */
947 {
953 /* If a padding record was made, declare it now since it will
954 never be declared otherwise. This is necessary to ensure
955 that its subtrees are properly marked. */
959 }
961 /* If this is a renaming, avoid as much as possible to create a new
962 object. However, in several cases, creating it is required.
963 This processing needs to be applied to the raw expression so
964 as to make it more likely to rename the underlying object. */
966 {
969 /* If the renamed object had padding, strip off the reference
970 to the inner object and reset our type. */
973 /* Strip useless conversions around the object. */
975 {
978 }
980 /* Or else, if the renamed object has an unconstrained type with
981 default discriminant, use the padded type. */
984 == gnu_type
988 /* Case 1: If this is a constant renaming stemming from a function
989 call, treat it as a normal object whose initial value is what is
990 being renamed. RM 3.3 says that the result of evaluating a
991 function call is a constant object. Treat constant literals
992 the same way. As a consequence, it can be the inner object of
993 a constant renaming. In this case, the renaming must be fully
994 instantiated, i.e. it cannot be a mere reference to (part of) an
995 existing object. */
997 {
1004 }
1006 /* Otherwise, see if we can proceed with a stabilized version of
1007 the renamed entity or if we need to make a new object. */
1009 {
1013 /* Case 2: If the renaming entity need not be materialized and
1014 the renamed expression is something we can stabilize, use
1015 that for the renaming. At the global level, we can only do
1016 this if we know no SAVE_EXPRs need be made, because the
1017 expression we return might be used in arbitrary conditional
1018 branches so we must force the evaluation of the SAVE_EXPRs
1019 immediately and this requires a proper function context.
1020 Note that an external constant is at the global level. */
1026 {
1027 maybe_stable_expr
1031 {
1032 /* ??? No DECL_EXPR is created so we need to mark
1033 the expression manually lest it is shared. */
1042 /* This assertion will fail if the renamed object
1043 isn't aligned enough as to make it possible to
1044 honor the alignment set on the renaming. */
1046 {
1047 unsigned int renamed_align
1052 }
1054 }
1056 /* The stabilization failed. Keep maybe_stable_expr
1057 untouched here to let the pointer case below know
1058 about that failure. */
1059 }
1061 /* Case 3: Make this into a constant pointer to the object we
1062 are to rename and attach the object to the pointer if it is
1063 something we can stabilize.
1065 From the proper scope, attached objects will be referenced
1066 directly instead of indirectly via the pointer to avoid
1067 subtle aliasing problems with non-addressable entities.
1068 They have to be stable because we must not evaluate the
1069 variables in the expression every time the renaming is used.
1070 The pointer is called a "renaming" pointer in this case.
1072 In the rare cases where we cannot stabilize the renamed
1073 object, we just make a "bare" pointer and the renamed
1074 object will always be accessed indirectly through it.
1076 Note that we need to preserve the volatility of the renamed
1077 object through the indirection. */
1079 gnu_type
1085 /* If the previous attempt at stabilizing failed, there is
1086 no point in trying again and we reuse the result without
1087 attaching it to the pointer. In this case it will only
1088 be used as the initializing expression of the pointer and
1089 thus needs no special treatment with regard to multiple
1090 evaluations.
1092 Otherwise, try to stabilize and attach the expression to
1093 the pointer if the stabilization succeeds.
1095 Note that this might introduce SAVE_EXPRs and we don't
1096 check whether we are at the global level or not. This
1097 is fine since we are building a pointer initializer and
1098 neither the pointer nor the initializing expression can
1099 be accessed before the pointer elaboration has taken
1100 place in a correct program.
1102 These SAVE_EXPRs will be evaluated at the right place
1103 by either the evaluation of the initializer for the
1104 non-global case or the elaboration code for the global
1105 case, and will be attached to the elaboration procedure
1106 in the latter case. */
1108 {
1109 maybe_stable_expr
1114 }
1119 else
1120 gnu_expr
1125 }
1126 }
1128 /* Make a volatile version of this object's type if we are to make
1129 the object volatile. We also interpret 13.3(19) conservatively
1130 and disallow any optimizations for such a non-constant object. */
1132 || (!const_flag
1135 || imported_p
1140 /* If we are defining an aliased object whose nominal subtype is
1141 unconstrained, the object is a record that contains both the
1142 template and the object. If there is an initializer, it will
1143 have already been converted to the right type, but we need to
1144 create the template if there is no initializer. */
1146 && !gnu_expr
1149 /* Beware that padding might have been introduced above. */
1152 == RECORD_TYPE
1153 && TYPE_CONTAINS_TEMPLATE_P
1155 {
1156 tree template_field
1164 NULL_TREE);
1167 }
1169 /* Convert the expression to the type of the object except in the
1170 case where the object's type is unconstrained or the object's type
1171 is a padded record whose field is of self-referential size. In
1172 the former case, converting will generate unnecessary evaluations
1173 of the CONSTRUCTOR to compute the size and in the latter case, we
1174 want to only copy the actual data. Also don't convert to a record
1175 type with a variant part from a record type without one, to keep
1176 the object simpler. */
1181 && CONTAINS_PLACEHOLDER_P
1189 /* If this is a pointer that doesn't have an initializing expression,
1190 initialize it to NULL, unless the object is imported. */
1193 && !gnu_expr
1197 /* If we are defining the object and it has an Address clause, we must
1198 either get the address expression from the saved GCC tree for the
1199 object if it has a Freeze node, or elaborate the address expression
1200 here since the front-end has guaranteed that the elaboration has no
1201 effects in this case. */
1203 {
1205 tree gnu_address
1211 /* Ignore the size. It's either meaningless or was handled
1212 above. */
1214 /* Convert the type of the object to a reference type that can
1215 alias everything as per 13.3(19). */
1216 gnu_type
1220 const_flag
1224 /* If this is a deferred constant, the initializer is attached to
1225 the full view. */
1227 gnu_expr
1228 = gnat_to_gnu
1231 /* If we don't have an initializing expression for the underlying
1232 variable, the initializing expression for the pointer is the
1233 specified address. Otherwise, we have to make a COMPOUND_EXPR
1234 to assign both the address and the initial value. */
1237 else
1238 gnu_expr
1240 build_binary_op
1243 gnu_address),
1244 gnu_expr),
1245 gnu_address);
1246 }
1248 /* If it has an address clause and we are not defining it, mark it
1249 as an indirect object. Likewise for Stdcall objects that are
1250 imported. */
1254 {
1255 /* Convert the type of the object to a reference type that can
1256 alias everything as per 13.3(19). */
1257 gnu_type
1261 /* No point in taking the address of an initializing expression
1262 that isn't going to be used. */
1265 /* If it has an address clause whose value is known at compile
1266 time, make the object a CONST_DECL. This will avoid a
1267 useless dereference. */
1269 {
1270 Node_Id gnat_address
1274 {
1277 }
1278 }
1281 }
1283 /* If we are at top level and this object is of variable size,
1284 make the actual type a hidden pointer to the real type and
1285 make the initializer be a memory allocation and initialization.
1286 Likewise for objects we aren't defining (presumed to be
1287 external references from other packages), but there we do
1288 not set up an initialization.
1290 If the object's size overflows, make an allocator too, so that
1291 Storage_Error gets raised. Note that we will never free
1292 such memory, so we presume it never will get allocated. */
1295 || !definition
1297 || (gnu_size
1299 size_binop
1301 bitsize_unit_node)),
1303 || !definition
1305 {
1310 /* In case this was a aliased object whose nominal subtype is
1311 unconstrained, the pointer above will be a thin pointer and
1312 build_allocator will automatically make the template.
1314 If we have a template initializer only (that we made above),
1315 pretend there is none and rely on what build_allocator creates
1316 again anyway. Otherwise (if we have a full initializer), get
1317 the data part and feed that to build_allocator.
1319 If we are elaborating a mutable object, tell build_allocator to
1320 ignore a possibly simpler size from the initializer, if any, as
1321 we must allocate the maximum possible size in this case. */
1323 {
1328 {
1329 gnu_alloc_type
1335 else
1336 gnu_expr
1337 = build_component_ref
1341 }
1346 gnat_entity);
1348 gnu_expr
1352 }
1353 else
1354 {
1357 }
1358 }
1360 /* If this object would go into the stack and has an alignment larger
1361 than the largest stack alignment the back-end can honor, resort to
1362 a variable of "aligning type". */
1365 {
1366 /* Create the new variable. No need for extra room before the
1367 aligned field as this is in automatic storage. */
1368 tree gnu_new_type
1372 tree gnu_new_var
1377 /* Initialize the aligned field if we have an initializer. */
1379 add_stmt_with_node
1381 build_component_ref
1384 gnu_expr),
1385 gnat_entity);
1387 /* And setup this entity as a reference to the aligned field. */
1389 gnu_expr
1390 = build_unary_op
1398 }
1400 /* If this is an aliased object with an unconstrained nominal subtype,
1401 we make its type a thin reference, i.e. the reference counterpart
1402 of a thin pointer, so that it points to the array part. This is
1403 aimed at making it easier for the debugger to decode the object.
1404 Note that we have to do that this late because of the couple of
1405 allocation adjustments that might be made just above. */
1409 {
1410 tree gnu_array
1413 /* In case the object with the template has already been allocated
1414 just above, we have nothing to do here. */
1416 {
1417 tree gnu_unc_var
1423 gnu_expr
1431 }
1433 gnu_type
1435 }
1440 /* Convert the expression to the type of the object except in the
1441 case where the object's type is unconstrained or the object's type
1442 is a padded record whose field is of self-referential size. In
1443 the former case, converting will generate unnecessary evaluations
1444 of the CONSTRUCTOR to compute the size and in the latter case, we
1445 want to only copy the actual data. Also don't convert to a record
1446 type with a variant part from a record type without one, to keep
1447 the object simpler. */
1452 && CONTAINS_PLACEHOLDER_P
1460 /* If this name is external or a name was specified, use it, but don't
1461 use the Interface_Name with an address clause (see cd30005). */
1468 /* If this is an aggregate constant initialized to a constant, force it
1469 to be statically allocated. This saves an initialization copy. */
1471 && const_flag
1480 /* Deal with a pragma Linker_Section on a constant or variable. */
1486 /* Now create the variable or the constant and set various flags. */
1487 gnu_decl
1496 /* If we are defining an Out parameter and optimization isn't enabled,
1497 create a fake PARM_DECL for debugging purposes and make it point to
1498 the VAR_DECL. Suppress debug info for the latter but make sure it
1499 will live in memory so that it can be accessed from within the
1500 debugger through the PARM_DECL. */
1502 && definition
1503 && debug_info_p
1504 && !optimize
1506 {
1513 }
1515 /* If this is a loop parameter, set the corresponding flag. */
1519 /* If this is a renaming pointer, attach the renamed object to it and
1520 register it if we are at the global level. Note that an external
1521 constant is at the global level. */
1523 {
1526 {
1529 }
1530 }
1532 /* If this is a constant and we are defining it or it generates a real
1533 symbol at the object level and we are referencing it, we may want
1534 or need to have a true variable to represent it:
1535 - if optimization isn't enabled, for debugging purposes,
1536 - if the constant is public and not overlaid on something else,
1537 - if its address is taken,
1538 - if either itself or its type is aliased. */
1547 {
1548 tree gnu_corr_var
1552 gnat_entity);
1556 /* As debugging information will be generated for the variable,
1557 do not generate debugging information for the constant. */
1560 else
1562 }
1564 /* If this is a constant, even if we don't need a true variable, we
1565 may need to avoid returning the initializer in every case. That
1566 can happen for the address of a (constant) constructor because,
1567 upon dereferencing it, the constructor will be reinjected in the
1568 tree, which may not be valid in every case; see lvalue_required_p
1569 for more details. */
1573 /* If this object is declared in a block that contains a block with an
1574 exception handler, and we aren't using the GCC exception mechanism,
1575 we must force this variable in memory in order to avoid an invalid
1576 optimization. */
1581 /* If this is a local variable with non-BLKmode and aggregate type,
1582 and optimization isn't enabled, then force it in memory so that
1583 a register won't be allocated to it with possible subparts left
1584 uninitialized and reaching the register allocator. */
1594 /* If we are defining an object with variable size or an object with
1595 fixed size that will be dynamically allocated, and we are using the
1596 setjmp/longjmp exception mechanism, update the setjmp buffer. */
1609 gnat_entity);
1611 /* Back-annotate Esize and Alignment of the object if not already
1612 known. Note that we pick the values of the type, not those of
1613 the object, to shield ourselves from low-level platform-dependent
1614 adjustments like alignment promotion. This is both consistent with
1615 all the treatment above, where alignment and size are set on the
1616 type of the object and not on the object directly, and makes it
1617 possible to support all confirming representation clauses. */
1619 used_by_ref);
1620 }
1624 /* Return a TYPE_DECL for "void" that we previously made. */
1629 /* A special case: for the types Character and Wide_Character in
1630 Standard, we do not list all the literals. So if the literals
1631 are not specified, make this an unsigned integer type. */
1633 {
1637 /* Set TYPE_STRING_FLAG for Character and Wide_Character types.
1638 This is needed by the DWARF-2 back-end to distinguish between
1639 unsigned integer types and character types. */
1641 }
1642 else
1643 {
1644 /* We have a list of enumeral constants in First_Literal. We make a
1645 CONST_DECL for each one and build into GNU_LITERAL_LIST the list
1646 to be placed into TYPE_FIELDS. Each node is itself a TREE_LIST
1647 whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
1648 value of the literal. But when we have a regular boolean type, we
1649 simplify this a little by using a BOOLEAN_TYPE. */
1654 Entity_Id gnat_literal;
1667 {
1668 tree gnu_value
1670 tree gnu_literal
1674 /* Do not generate debug info for individual enumerators. */
1677 gnu_list
1679 }
1684 /* Note that the bounds are updated at the end of this function
1685 to avoid an infinite recursion since they refer to the type. */
1687 }
1693 /* For integer types, just make a signed type the appropriate number
1694 of bits. */
1699 {
1700 /* For modular types, make the unsigned type of the proper number
1701 of bits and then set up the modulus, if required. */
1704 /* Packed Array Impl. Types are supposed to be subtypes only. */
1709 /* Get the modulus in this type. If it overflows, assume it is because
1710 it is equal to 2**Esize. Note that there is no overflow checking
1711 done on unsigned type, so we detect the overflow by looking for
1712 a modulus of zero, which is otherwise invalid. */
1716 {
1721 }
1723 /* If the upper bound is not maximal, make an extra subtype. */
1726 {
1733 }
1734 }
1743 /* For integral subtypes, we make a new INTEGER_TYPE. Note that we do
1744 not want to call create_range_type since we would like each subtype
1745 node to be distinct. ??? Historically this was in preparation for
1746 when memory aliasing is implemented, but that's obsolete now given
1747 the call to relate_alias_sets below.
1749 The TREE_TYPE field of the INTEGER_TYPE points to the base type;
1750 this fact is used by the arithmetic conversion functions.
1752 We elaborate the Ancestor_Subtype if it is not in the current unit
1753 and one of our bounds is non-static. We do this to ensure consistent
1754 naming in the case where several subtypes share the same bounds, by
1755 elaborating the first such subtype first, thus using its name. */
1764 /* Set the precision to the Esize except for bit-packed arrays. */
1769 /* This should be an unsigned type if the base type is unsigned or
1770 if the lower bound is constant and non-negative or if the type
1771 is biased. */
1776 else
1780 SET_TYPE_RM_MIN_VALUE
1786 SET_TYPE_RM_MAX_VALUE
1795 /* Inherit our alias set from what we're a subtype of. Subtypes
1796 are not different types and a pointer can designate any instance
1797 within a subtype hierarchy. */
1800 /* One of the above calls might have caused us to be elaborated,
1801 so don't blow up if so. */
1803 {
1806 }
1808 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
1812 /* For a packed array, make the original array type a parallel type. */
1816 discrete_type:
1818 /* We have to handle clauses that under-align the type specially. */
1821 && Present
1824 {
1828 }
1830 /* If the type we are dealing with represents a bit-packed array,
1831 we need to have the bits left justified on big-endian targets
1832 and right justified on little-endian targets. We also need to
1833 ensure that when the value is read (e.g. for comparison of two
1834 such values), we only get the good bits, since the unused bits
1835 are uninitialized. Both goals are accomplished by wrapping up
1836 the modular type in an enclosing record type. */
1839 {
1842 /* Set the RM size before wrapping up the original type. */
1847 /* Create a stripped-down declaration, mainly for debugging. */
1849 gnat_entity);
1851 /* Now save it and build the enclosing record type. */
1861 /* Propagate the alignment of the modular type to the record type,
1862 unless there is an alignment clause that under-aligns the type.
1863 This means that bit-packed arrays are given "ceil" alignment for
1864 their size by default, which may seem counter-intuitive but makes
1865 it possible to overlay them on modular types easily. */
1869 /* Propagate the reverse storage order flag to the record type so
1870 that the required byte swapping is performed when retrieving the
1871 enclosed modular value. */
1877 /* Don't declare the field as addressable since we won't be taking
1878 its address and this would prevent create_field_decl from making
1879 a bitfield. */
1880 gnu_field
1884 /* Do not emit debug info until after the parallel type is added. */
1890 {
1891 /* Make the original array type a parallel type. */
1895 }
1896 }
1898 /* If the type we are dealing with has got a smaller alignment than the
1899 natural one, we need to wrap it up in a record type and misalign the
1900 latter; we reuse the padding machinery for this purpose. Note that,
1901 even if the record type is marked as packed because of misalignment,
1902 we don't pack the field so as to give it the size of the type. */
1904 {
1907 /* Set the RM size before wrapping up the type. */
1911 /* Create a stripped-down declaration, mainly for debugging. */
1913 gnat_entity);
1915 /* Now save it and build the enclosing record type. */
1927 /* Don't declare the field as addressable since we won't be taking
1928 its address and this would prevent create_field_decl from making
1929 a bitfield. */
1930 gnu_field
1938 }
1943 /* The type of the Low and High bounds can be our type if this is
1944 a type from Standard, so set them at the end of the function. */
1951 /* See the E_Signed_Integer_Subtype case for the rationale. */
1968 SET_TYPE_RM_MIN_VALUE
1974 SET_TYPE_RM_MAX_VALUE
1980 /* Inherit our alias set from what we're a subtype of, as for
1981 integer subtypes. */
1984 /* One of the above calls might have caused us to be elaborated,
1985 so don't blow up if so. */
1989 /* Array Types and Subtypes
1991 Unconstrained array types are represented by E_Array_Type and
1992 constrained array types are represented by E_Array_Subtype. There
1993 are no actual objects of an unconstrained array type; all we have
1994 are pointers to that type.
1996 The following fields are defined on array types and subtypes:
1998 Component_Type Component type of the array.
1999 Number_Dimensions Number of dimensions (an int).
2000 First_Index Type of first index. */
2003 {
2004 const bool convention_fortran_p
2007 tree gnu_template_type;
2008 tree gnu_ptr_template;
2015 tree comp_type;
2017 /* Create the type for the component now, as it simplifies breaking
2018 type reference loops. */
2019 comp_type
2022 {
2023 /* As a side effect, the type may have been translated. */
2026 }
2028 /* We complete an existing dummy fat pointer type in place. This both
2029 avoids further complex adjustments in update_pointer_to and yields
2030 better debugging information in DWARF by leveraging the support for
2031 incomplete declarations of "tagged" types in the DWARF back-end. */
2034 {
2037 /* Save the contents of the dummy type for update_pointer_to. */
2039 gnu_ptr_template =
2042 }
2043 else
2044 {
2048 }
2050 /* Make a node for the array. If we are not defining the array
2051 suppress expanding incomplete types. */
2055 {
2056 defer_incomplete_level++;
2058 }
2060 /* Build the fat pointer type. Use a "void *" object instead of
2061 a pointer to the array type since we don't have the array type
2062 yet (it will reference the fat pointer via the bounds). */
2063 tem
2071 {
2072 /* We are going to lay it out again so reset the alias set. */
2078 {
2081 }
2082 }
2083 else
2084 {
2087 }
2089 /* Build a reference to the template from a PLACEHOLDER_EXPR that
2090 is the fat pointer. This will be used to access the individual
2091 fields once we build them. */
2095 gnu_template_reference
2100 /* Now create the GCC type for each index and add the fields for that
2101 index to the template. */
2107 {
2109 tree gnu_index_base_type
2114 /* Make the FIELD_DECLs for the low and high bounds of this
2115 type and then make extractions of these fields from the
2116 template. */
2119 gnu_index_base_type,
2127 gnu_index_base_type,
2135 /* We can't use build_component_ref here since the template type
2136 isn't complete yet. */
2139 NULL_TREE);
2142 NULL_TREE);
2148 /* Compute the size of this dimension. See the E_Array_Subtype
2149 case below for the rationale. */
2150 gnu_high
2154 gnu_max,
2157 /* Make a range type with the new range in the Ada base type.
2158 Then make an index type with the size range in sizetype. */
2162 gnu_orig_min,
2163 gnu_orig_max),
2164 gnat_entity);
2166 /* Update the maximum size of the array in elements. */
2168 {
2170 tree gnu_min
2172 tree gnu_max
2174 tree gnu_this_max
2181 else
2182 gnu_max_size
2184 }
2188 }
2190 /* Install all the fields into the template. */
2195 gnu_template_fields
2198 debug_info_p);
2201 /* If Component_Size is not already specified, annotate it with the
2202 size of the component. */
2207 /* Compute the maximum size of the array in units and bits. */
2209 {
2215 }
2216 else
2219 /* Now build the array type. */
2222 {
2227 else
2232 /* If it is passed by reference, force BLKmode to ensure that
2233 objects of this type will always be put in memory. */
2237 }
2241 /* If an alignment is specified, use it if valid. But ignore it
2242 for the original type of packed array types. If the alignment
2243 was requested with an explicit alignment clause, state so. */
2246 {
2252 }
2256 /* Adjust the type of the pointer-to-array field of the fat pointer
2257 and record the aliasing relationships if necessary. */
2262 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2263 corresponding fat pointer. */
2270 /* If the maximum size doesn't overflow, use it. */
2276 {
2281 }
2285 gnat_entity);
2287 /* Give the fat pointer type a name. If this is a packed array, tell
2288 the debugger how to interpret the underlying bits. */
2291 else
2295 gnat_entity);
2297 /* Create the type to be designated by thin pointers: a record type for
2298 the array and its template. We used to shift the fields to have the
2299 template at a negative offset, but this was somewhat of a kludge; we
2300 now shift thin pointer values explicitly but only those which have a
2301 TYPE_UNCONSTRAINED_ARRAY attached to the designated RECORD_TYPE. */
2304 debug_info_p);
2308 }
2313 /* This is the actual data type for array variables. Multidimensional
2314 arrays are implemented as arrays of arrays. Note that arrays which
2315 have sparse enumeration subtypes as index components create sparse
2316 arrays, which is obviously space inefficient but so much easier to
2317 code for now.
2319 Also note that the subtype never refers to the unconstrained array
2320 type, which is somewhat at variance with Ada semantics.
2322 First check to see if this is simply a renaming of the array type.
2323 If so, the result is the array type. */
2327 ;
2328 else
2329 {
2331 const bool convention_fortran_p
2340 /* First create the GCC type for each index and find out whether
2341 special types are needed for debugging information. */
2344 gnat_base_index
2350 {
2353 tree gnu_orig_min
2356 tree gnu_orig_max
2361 tree gnu_base_index_type
2363 tree gnu_base_index_base_type
2365 tree gnu_base_orig_min
2368 tree gnu_base_orig_max
2371 tree gnu_high;
2373 /* See if the base array type is already flat. If it is, we
2374 are probably compiling an ACATS test but it will cause the
2375 code below to malfunction if we don't handle it specially. */
2379 {
2383 }
2385 /* Similarly, if one of the values overflows in sizetype and the
2386 range is null, use 1..0 for the sizetype bounds. */
2391 {
2395 }
2397 /* If the minimum and maximum values both overflow in sizetype,
2398 but the difference in the original type does not overflow in
2399 sizetype, ignore the overflow indication. */
2403 && !TREE_OVERFLOW
2406 gnu_orig_max,
2407 gnu_orig_min))))
2408 {
2412 }
2414 /* Compute the size of this dimension in the general case. We
2415 need to provide GCC with an upper bound to use but have to
2416 deal with the "superflat" case. There are three ways to do
2417 this. If we can prove that the array can never be superflat,
2418 we can just use the high bound of the index type. */
2421 /* Bit-Packed Array Impl. Types are never superflat. */
2423 && Is_Bit_Packed_Array
2427 /* Otherwise, if the high bound is constant but the low bound is
2428 not, we use the expression (hb >= lb) ? lb : hb + 1 for the
2429 lower bound. Note that the comparison must be done in the
2430 original type to avoid any overflow during the conversion. */
2433 {
2435 gnu_min
2438 boolean_type_node,
2439 gnu_orig_max,
2440 gnu_orig_min),
2441 gnu_min,
2443 size_one_node));
2444 }
2446 /* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
2447 in all the other cases. Note that, here as well as above,
2448 the condition used in the comparison must be equivalent to
2449 the condition (length != 0). This is relied upon in order
2450 to optimize array comparisons in compare_arrays. Moreover
2451 we use int_const_binop for the shift by 1 if the bound is
2452 constant to avoid any unwanted overflow. */
2453 else
2454 gnu_high
2457 boolean_type_node,
2458 gnu_orig_max,
2459 gnu_orig_min),
2460 gnu_max,
2463 size_one_node)
2465 size_one_node));
2467 /* Reuse the index type for the range type. Then make an index
2468 type with the size range in sizetype. */
2471 gnat_entity);
2473 /* Update the maximum size of the array in elements. Here we
2474 see if any constraint on the index type of the base type
2475 can be used in the case of self-referential bound on the
2476 index type of the subtype. We look for a non-"infinite"
2477 and non-self-referential bound from any type involved and
2478 handle each bound separately. */
2480 {
2483 tree gnu_base_index_base_type
2485 tree gnu_base_base_min
2488 tree gnu_base_base_max
2509 else
2510 {
2511 tree gnu_this_max;
2513 /* Use int_const_binop if the bounds are constant to
2514 avoid any unwanted overflow. */
2517 gnu_this_max
2520 gnu_base_max,
2521 gnu_base_min));
2522 else
2523 gnu_this_max
2526 gnu_base_max,
2527 gnu_base_min));
2529 gnu_max_size
2531 }
2532 }
2534 /* We need special types for debugging information to point to
2535 the index types if they have variable bounds, are not integer
2536 types or are biased. */
2545 }
2547 /* Then flatten: create the array of arrays. For an array type
2548 used to implement a packed array, get the component type from
2549 the original array type since the representation clauses that
2550 can affect it are on the latter. */
2553 {
2558 /* One of the above calls might have caused us to be elaborated,
2559 so don't blow up if so. */
2561 {
2564 }
2565 }
2566 else
2567 {
2569 debug_info_p);
2571 /* One of the above calls might have caused us to be elaborated,
2572 so don't blow up if so. */
2574 {
2577 }
2578 }
2580 /* Compute the maximum size of the array in units and bits. */
2582 {
2588 }
2589 else
2592 /* Now build the array type. */
2594 {
2600 else
2605 /* See the E_Array_Type case for the rationale. */
2609 }
2613 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
2617 /* If we are at file level and this is a multi-dimensional array,
2618 we need to make a variable corresponding to the stride of the
2619 inner dimensions. */
2621 {
2623 tree gnu_arr_type;
2629 {
2637 /* ??? For now, store the size as a multiple of the
2638 alignment of the element type in bytes so that we
2639 can see the alignment from the tree. */
2642 gnat_entity,
2647 /* ??? create_type_decl is not invoked on the inner types so
2648 the MULT_EXPR node built above will never be marked. */
2650 }
2651 }
2653 /* If we need to write out a record type giving the names of the
2654 bounds for debugging purposes, do it now and make the record
2655 type a parallel type. This is not needed for a packed array
2656 since the bounds are conveyed by the original array type. */
2658 && debug_info_p
2660 {
2663 tree gnu_field;
2669 {
2673 /* Make sure to reference the types themselves, and not just
2674 their names, as the debugger may fall back on them. */
2680 }
2684 }
2686 /* If this is a packed array type, make the original array type a
2687 parallel type. Otherwise, do it for the base array type if it
2688 isn't artificial to make sure it is kept in the debug info. */
2690 {
2693 else
2694 {
2695 tree gnu_base_decl
2700 }
2701 }
2708 /* If the size is self-referential and the maximum size doesn't
2709 overflow, use it. */
2711 && gnu_max_size
2716 {
2722 }
2724 /* Set our alias set to that of our base type. This gives all
2725 array subtypes the same alias set. */
2728 /* If this is a packed type, make this type the same as the packed
2729 array type, but do some adjusting in the type first. */
2731 {
2732 Entity_Id gnat_index;
2733 tree gnu_inner;
2735 /* First finish the type we had been making so that we output
2736 debugging information for it. */
2739 gnu_type
2741 /* Make it artificial only if the base type was artificial too.
2742 That's sort of "morally" true and will make it possible for
2743 the debugger to look it up by name in DWARF, which is needed
2744 in order to decode the packed array type. */
2745 gnu_decl
2751 /* Save it as our equivalent in case the call below elaborates
2752 this type again. */
2755 gnu_decl
2768 /* We need to attach the index type to the type we just made so
2769 that the actual bounds can later be put into a template. */
2774 {
2776 {
2777 /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
2778 TYPE_MODULUS for modular types so we make an extra
2779 subtype if necessary. */
2781 {
2782 tree gnu_subtype
2791 }
2795 #ifdef ENABLE_CHECKING
2796 /* Check for other cases of overloading. */
2798 #endif
2799 }
2804 SET_TYPE_ACTUAL_BOUNDS
2811 SET_TYPE_ACTUAL_BOUNDS
2817 }
2818 }
2820 else
2821 /* Abort if packed array with no Packed_Array_Impl_Type. */
2823 }
2827 /* Create the type for a string literal. */
2828 {
2829 Entity_Id gnat_full_type
2834 tree gnu_string_array_type
2836 tree gnu_string_index_type
2839 tree gnu_lower_bound
2842 tree gnu_length
2844 gnu_string_index_type);
2845 tree gnu_upper_bound
2847 gnu_lower_bound,
2850 integer_one_node)));
2851 tree gnu_index_type
2855 gnu_lower_bound,
2856 gnu_upper_bound),
2857 gnat_entity);
2859 gnu_type
2862 gnu_index_type);
2866 }
2869 /* Record Types and Subtypes
2871 The following fields are defined on record types:
2873 Has_Discriminants True if the record has discriminants
2874 First_Discriminant Points to head of list of discriminants
2875 First_Entity Points to head of list of fields
2876 Is_Tagged_Type True if the record is tagged
2878 Implementation of Ada records and discriminated records:
2880 A record type definition is transformed into the equivalent of a C
2881 struct definition. The fields that are the discriminants which are
2882 found in the Full_Type_Declaration node and the elements of the
2883 Component_List found in the Record_Type_Definition node. The
2884 Component_List can be a recursive structure since each Variant of
2885 the Variant_Part of the Component_List has a Component_List.
2887 Processing of a record type definition comprises starting the list of
2888 field declarations here from the discriminants and the calling the
2889 function components_to_record to add the rest of the fields from the
2890 component list and return the gnu type node. The function
2891 components_to_record will call itself recursively as it traverses
2892 the tree. */
2896 {
2897 gnu_type
2898 = build_complex_type
2899 (get_unpadded_type
2902 (Component_List
2903 (Type_Definition
2907 }
2909 {
2912 Node_Id gnat_constr;
2913 Entity_Id gnat_field;
2915 tree gnu_get_parent;
2916 /* Set PACKED in keeping with gnat_to_gnu_field. */
2917 const int packed
2929 const bool is_extension
2935 /* See if all fields have a rep clause. Stop when we find one
2936 that doesn't. */
2944 {
2947 }
2949 /* If this is a record extension, go a level further to find the
2950 record definition. Also, verify we have a Parent_Subtype. */
2952 {
2959 }
2961 /* Make a node for the record. If we are not defining the record,
2962 suppress expanding incomplete types. */
2971 {
2972 defer_incomplete_level++;
2974 }
2976 /* If both a size and rep clause was specified, put the size in
2977 the record type now so that it can get the proper mode. */
2982 /* Always set the alignment here so that it can be used to
2983 set the mode, if it is making the alignment stricter. If
2984 it is invalid, it will be checked again below. If this is to
2985 be Atomic, choose a default alignment of a word unless we know
2986 the size and it's smaller. */
2991 {
2995 }
2996 /* If a type needs strict alignment, the minimum size will be the
2997 type size instead of the RM size (see validate_size). Cap the
2998 alignment, lest it causes this type size to become too large. */
3000 {
3005 }
3006 else
3009 /* If we have a Parent_Subtype, make a field for the parent. If
3010 this record has rep clauses, force the position to zero. */
3012 {
3015 tree gnu_parent;
3017 /* A major complexity here is that the parent subtype will
3018 reference our discriminants in its Stored_Constraint list.
3019 But those must reference the parent component of this record
3020 which is precisely of the parent subtype we have not built yet!
3021 To break the circle we first build a dummy COMPONENT_REF which
3022 represents the "get to the parent" operation and initialize
3023 each of those discriminants to a COMPONENT_REF of the above
3024 dummy parent referencing the corresponding discriminant of the
3025 base type of the parent subtype. */
3030 gnu_dummy_parent_type),
3031 NULL_TREE);
3038 {
3039 tree gnu_field
3042 save_gnu_tree
3047 }
3049 /* Then we build the parent subtype. If it has discriminants but
3050 the type itself has unknown discriminants, this means that it
3051 doesn't contain information about how the discriminants are
3052 derived from those of the ancestor type, so it cannot be used
3053 directly. Instead it is built by cloning the parent subtype
3054 of the underlying record view of the type, for which the above
3055 derivation of discriminants has been made explicit. */
3058 {
3061 /* If we are defining the type, the underlying record
3062 view must already have been elaborated at this point.
3063 Otherwise do it now as its parent subtype cannot be
3064 technically elaborated on its own. */
3067 else
3072 /* Substitute the "get to the parent" of the type for that
3073 of its underlying record view in the cloned type. */
3078 {
3080 tree gnu_ref
3083 gnu_parent
3085 }
3086 }
3087 else
3090 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
3091 initially built. The discriminants must reference the fields
3092 of the parent subtype and not those of its base type for the
3093 placeholder machinery to properly work. */
3095 {
3096 /* The actual parent subtype is the full view. */
3098 {
3101 else
3103 }
3109 {
3110 Entity_Id field;
3119 }
3120 }
3122 /* The "get to the parent" COMPONENT_REF must be given its
3123 proper type... */
3126 /* ...and reference the _Parent field of this record. */
3127 gnu_field
3130 has_rep
3132 has_rep
3138 }
3140 /* Make the fields for the discriminants and put them into the record
3141 unless it's an Unchecked_Union. */
3146 {
3147 /* If this is a record extension and this discriminant is the
3148 renaming of another discriminant, we've handled it above. */
3153 gnu_field
3155 debug_info_p);
3157 /* Make an expression using a PLACEHOLDER_EXPR from the
3158 FIELD_DECL node just created and link that with the
3159 corresponding GNAT defining identifier. */
3167 {
3170 }
3171 }
3173 /* If we have a derived untagged type that renames discriminants in
3174 the root type, the (stored) discriminants are a just copy of the
3175 discriminants of the root type. This means that any constraints
3176 added by the renaming in the derivation are disregarded as far
3177 as the layout of the derived type is concerned. To rescue them,
3178 we change the type of the (stored) discriminants to a subtype
3179 with the bounds of the type of the visible discriminants. */
3181 && !is_extension
3187 /* Ignore access discriminants. */
3190 {
3194 /* If the scope of the discriminant is not the record type,
3195 this means that we're processing the implicit full view
3196 of a type derived from a private discriminated type: in
3197 this case, the Stored_Constraint list is simply copied
3198 from the partial view, see Build_Derived_Private_Type.
3199 So we need to retrieve the corresponding discriminant
3200 of the implicit full view, otherwise we will abort. */
3202 {
3203 Entity_Id field;
3212 }
3215 gnu_ref
3219 /* GNU_REF must be an expression using a PLACEHOLDER_EXPR built
3220 just above for one of the stored discriminants. */
3224 {
3226 tree gnu_subtype
3237 }
3238 }
3240 /* Add the fields into the record type and finish it up. */
3248 /* If it is passed by reference, force BLKmode to ensure that objects
3249 of this type will always be put in memory. */
3256 /* Fill in locations of fields. */
3259 /* If there are any entities in the chain corresponding to components
3260 that we did not elaborate, ensure we elaborate their types if they
3261 are Itypes. */
3271 /* If this is a record type associated with an exception definition,
3272 equate its fields to those of the standard exception type. This
3273 will make it possible to convert between them. */
3275 {
3276 tree gnu_std_field;
3279 gnu_field;
3284 }
3285 }
3289 /* If an equivalent type is present, that is what we should use.
3290 Otherwise, fall through to handle this like a record subtype
3291 since it may have constraints. */
3293 {
3297 }
3299 /* ... fall through ... */
3302 /* If Cloned_Subtype is Present it means this record subtype has
3303 identical layout to that type or subtype and we should use
3304 that GCC type for this one. The front end guarantees that
3305 the component list is shared. */
3307 {
3312 }
3314 /* Otherwise, first ensure the base type is elaborated. Then, if we are
3315 changing the type, make a new type with each field having the type of
3316 the field in the new subtype but the position computed by transforming
3317 every discriminant reference according to the constraints. We don't
3318 see any difference between private and non-private type here since
3319 derivations from types should have been deferred until the completion
3320 of the private type. */
3321 else
3322 {
3324 tree gnu_base_type;
3327 {
3328 defer_incomplete_level++;
3330 }
3335 {
3338 }
3340 /* If this is a record subtype associated with a dispatch table,
3341 strip the suffix. This is necessary to make sure 2 different
3342 subtypes associated with the imported and exported views of a
3343 dispatch table are properly merged in LTO mode. */
3345 {
3352 }
3354 /* When the subtype has discriminants and these discriminants affect
3355 the initial shape it has inherited, factor them in. But for an
3356 Unchecked_Union (it must be an Itype), just return the type.
3357 We can't just test Is_Constrained because private subtypes without
3358 discriminants of types with discriminants with default expressions
3359 are Is_Constrained but aren't constrained! */
3366 {
3372 Entity_Id gnat_field;
3382 /* Set the size, alignment and alias set of the new type to
3383 match that of the old one, doing required substitutions. */
3385 gnu_subst_list);
3389 else
3392 /* Look for REP and variant parts in the base type. */
3396 /* If there is a variant part, we must compute whether the
3397 constraints statically select a particular variant. If
3398 so, we simply drop the qualified union and flatten the
3399 list of fields. Otherwise we'll build a new qualified
3400 union for the variants that are still relevant. */
3402 {
3406 gnu_variant_list
3408 gnu_subst_list,
3409 vNULL);
3411 /* If all the qualifiers are unconditionally true, the
3412 innermost variant is statically selected. */
3416 {
3419 }
3421 /* Otherwise, create the new variants. */
3424 {
3427 tree suffix
3429 IDENTIFIER_POINTER
3437 gnu_subst_list);
3439 }
3440 }
3441 else
3442 {
3445 }
3447 /* Make a list of fields and their position in the base type. */
3448 gnu_pos_list
3455 /* Now go down every component in the subtype and compute its
3456 size and position from those of the component in the base
3457 type and from the constraints of the subtype. */
3465 && Underlying_Type
3468 {
3470 Entity_Id gnat_old_field
3472 tree gnu_old_field
3478 /* If the type is the same, retrieve the GCC type from the
3479 old field to take into account possible adjustments. */
3482 else
3485 /* If there was a component clause, the field types must be
3486 the same for the type and subtype, so copy the data from
3487 the old field to avoid recomputation here. Also if the
3488 field is justified modular and the optimization in
3489 gnat_to_gnu_field was applied. */
3495 {
3498 }
3500 /* If the old field was packed and of constant size, we
3501 have to get the old size here, as it might differ from
3502 what the Etype conveys and the latter might overlap
3503 onto the following field. Try to arrange the type for
3504 possible better packing along the way. */
3508 {
3513 gnu_field_type
3515 }
3517 else
3520 /* If the context of the old field is the base type or its
3521 REP part (if any), put the field directly in the new
3522 type; otherwise look up the context in the variant list
3523 and put the field either in the new type if there is a
3524 selected variant or in one of the new variants. */
3526 || (gnu_rep_part
3529 else
3530 {
3533 tree rep_part;
3541 {
3544 else
3546 }
3547 else
3548 /* The front-end may pass us "ghost" components if
3549 it fails to recognize that a constrained subtype
3550 is statically constrained. Discard them. */
3552 }
3554 /* Now create the new field modeled on the old one. */
3555 gnu_field
3561 /* Put it in one of the new variants directly. */
3563 {
3566 }
3568 /* To match the layout crafted in components_to_record,
3569 if this is the _Tag or _Parent field, put it before
3570 any other fields. */
3575 /* Similarly, if this is the _Controller field, put
3576 it before the other fields except for the _Tag or
3577 _Parent field. */
3579 {
3582 }
3584 /* Otherwise, if this is a regular field, put it after
3585 the other fields. */
3586 else
3587 {
3594 }
3597 }
3599 /* If there is a variant list, a selected variant and the fields
3600 all have a constant position, put them in order of increasing
3601 position to match that of constant CONSTRUCTORs. Likewise if
3602 there is no variant list but a REP part, since the latter has
3603 been flattened in the process. */
3607 {
3619 {
3622 }
3623 }
3625 /* If there is a variant list and no selected variant, we need
3626 to create the nest of variant parts from the old nest. */
3628 {
3629 tree new_variant_part
3635 }
3637 /* Now go through the entities again looking for Itypes that
3638 we have not elaborated but should (e.g., Etypes of fields
3639 that have Original_Components). */
3647 /* Do not emit debug info for the type yet since we're going to
3648 modify it below. */
3653 /* See the E_Record_Type case for the rationale. */
3660 /* Fill in locations of fields. */
3663 /* If debugging information is being written for the type, write
3664 a record that shows what we are a subtype of and also make a
3665 variable that indicates our size, if still variable. */
3667 {
3669 tree gnu_unpad_base_name
3677 build_reference_type
3679 gnu_subtype_marker,
3694 gnat_entity);
3695 }
3700 /* Now we can finalize it. */
3702 }
3704 /* Otherwise, go down all the components in the new type and make
3705 them equivalent to those in the base type. */
3706 else
3707 {
3717 gnat_to_gnu_field_decl
3720 }
3721 }
3725 /* Use the special descriptor type for dispatch tables if needed,
3726 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3727 Note that we are only required to do so for static tables in
3728 order to be compatible with the C++ ABI, but Ada 2005 allows
3729 to extend library level tagged types at the local level so
3730 we do it in the non-static case as well. */
3733 {
3737 }
3739 /* ... fall through ... */
3742 /* If we are not defining this entity, and we have incomplete
3743 entities being processed above us, make a dummy type and
3744 fill it in later. */
3746 {
3749 gnu_type
3750 = build_pointer_type
3765 }
3767 /* ... fall through ... */
3774 {
3775 /* The designated type and its equivalent type for gigi. */
3778 /* Whether it comes from a limited with. */
3779 bool is_from_limited_with
3782 /* The "full view" of the designated type. If this is an incomplete
3783 entity from a limited with, treat its non-limited view as the full
3784 view. Otherwise, if this is an incomplete or private type, use the
3785 full view. In the former case, we might point to a private type,
3786 in which case, we need its full view. Also, we want to look at the
3787 actual type used for the representation, so this takes a total of
3788 three steps. */
3789 Entity_Id gnat_desig_full_direct_first
3790 = (is_from_limited_with
3794 Entity_Id gnat_desig_full_direct
3795 = ((is_from_limited_with
3800 Entity_Id gnat_desig_full
3802 /* The type actually used to represent the designated type, either
3803 gnat_desig_full or gnat_desig_equiv. */
3804 Entity_Id gnat_desig_rep;
3805 /* True if this is a pointer to an unconstrained array. */
3807 /* We want to know if we'll be seeing the freeze node for any
3808 incomplete type we may be pointing to. */
3809 bool in_main_unit
3813 /* True if we make a dummy type here. */
3815 /* The mode to be used for the pointer type. */
3817 /* The GCC type used for the designated type. */
3823 /* If either the designated type or its full view is an unconstrained
3824 array subtype, replace it with the type it's a subtype of. This
3825 avoids problems with multiple copies of unconstrained array types.
3826 Likewise, if the designated type is a subtype of an incomplete
3827 record type, use the parent type to avoid order of elaboration
3828 issues. This can lose some code efficiency, but there is no
3829 alternative. */
3840 /* Set the type that's actually the representation of the designated
3841 type and also flag whether we have a unconstrained array. */
3842 gnat_desig_rep
3844 is_unconstrained_array
3847 /* If we are pointing to an incomplete type whose completion is an
3848 unconstrained array, make dummy fat and thin pointer types to it.
3849 Likewise if the type itself is dummy or an unconstrained array. */
3853 && TYPE_IS_DUMMY_P
3855 || (!in_main_unit
3858 || (in_main_unit
3859 && is_from_limited_with
3861 {
3864 else
3865 {
3868 }
3870 /* If the call above got something that has a pointer, the pointer
3871 is our type. This could have happened either because the type
3872 was elaborated or because somebody else executed the code. */
3876 }
3878 /* If we already know what the full type is, use it. */
3883 /* Get the type of the thing we are to point to and build a pointer to
3884 it. If it is a reference to an incomplete or private type with a
3885 full view that is a record, make a dummy type node and get the
3886 actual type later when we have verified it is safe. */
3892 /* Likewise if we are pointing to a record or array and we are
3893 to defer elaborating incomplete types. We do this as this
3894 access type may be the full view of a private type. Note
3895 that the unconstrained array case is handled above. */
3901 /* If this is a reference from a limited_with type back to our
3902 main unit and there's a freeze node for it, either we have
3903 already processed the declaration and made the dummy type,
3904 in which case we just reuse the latter, or we have not yet,
3905 in which case we make the dummy type and it will be reused
3906 when the declaration is finally processed. In both cases,
3907 the pointer eventually created below will be automatically
3908 adjusted when the freeze node is processed. Note that the
3909 unconstrained array case is handled above. */
3910 || (in_main_unit
3911 && is_from_limited_with
3913 {
3916 }
3918 /* Otherwise handle the case of a pointer to itself. */
3920 {
3921 gnu_type
3925 }
3927 /* If expansion is disabled, the equivalent type of a concurrent type
3928 is absent, so build a dummy pointer type. */
3932 /* Finally, handle the default case where we can just elaborate our
3933 designated type. */
3934 else
3937 /* It is possible that a call to gnat_to_gnu_type above resolved our
3938 type. If so, just return it. */
3940 {
3943 }
3945 /* If we haven't done it yet, build the pointer type the usual way. */
3947 {
3948 /* Modify the designated type if we are pointing only to constant
3949 objects, but don't do it for unconstrained arrays. */
3952 {
3953 gnu_desig_type
3956 /* Some extra processing is required if we are building a
3957 pointer to an incomplete type (in the GCC sense). We might
3958 have such a type if we just made a dummy, or directly out
3959 of the call to gnat_to_gnu_type above if we are processing
3960 an access type for a record component designating the
3961 record type itself. */
3963 {
3964 /* We must ensure that the pointer to variant we make will
3965 be processed by update_pointer_to when the initial type
3966 is completed. Pretend we made a dummy and let further
3967 processing act as usual. */
3970 /* We must ensure that update_pointer_to will not retrieve
3971 the dummy variant when building a properly qualified
3972 version of the complete type. We take advantage of the
3973 fact that get_qualified_type is requiring TYPE_NAMEs to
3974 match to influence build_qualified_type and then also
3975 update_pointer_to here. */
3978 }
3979 }
3981 gnu_type
3984 }
3986 /* If we are not defining this object and we have made a dummy pointer,
3987 save our current definition, evaluate the actual type, and replace
3988 the tentative type we made with the actual one. If we are to defer
3989 actually looking up the actual type, make an entry in the deferred
3990 list. If this is from a limited with, we may have to defer to the
3991 end of the current unit. */
3993 {
3994 tree gnu_old_desig_type;
3997 {
4000 gnu_type = build_pointer_type
4002 }
4003 else
4015 /* Note that the call to gnat_to_gnu_type on gnat_desig_equiv might
4016 update gnu_old_desig_type directly, in which case it will not be
4017 a dummy type any more when we get into update_pointer_to.
4019 This can happen e.g. when the designated type is a record type,
4020 because their elaboration starts with an initial node from
4021 make_dummy_type, which may be the same node as the one we got.
4023 Besides, variants of this non-dummy type might have been created
4024 along the way. update_pointer_to is expected to properly take
4025 care of those situations. */
4027 {
4030 }
4031 else
4032 {
4035 = (is_from_limited_with
4041 }
4042 }
4043 }
4050 else
4051 {
4052 /* The run-time representation is the equivalent type. */
4055 }
4068 /* We treat this as identical to its base type; any constraint is
4069 meaningful only to the front-end.
4071 The designated type must be elaborated as well, if it does
4072 not have its own freeze node. Designated (sub)types created
4073 for constrained components of records with discriminants are
4074 not frozen by the front-end and thus not elaborated by gigi,
4075 because their use may appear before the base type is frozen,
4076 and because it is not clear that they are needed anywhere in
4077 gigi. With the current model, there is no correct place where
4078 they could be elaborated. */
4085 {
4086 /* If we are not defining this entity, and we have incomplete
4087 entities being processed above us, make a dummy type and
4088 elaborate it later. */
4090 {
4093 p->old_type
4098 }
4101 Incomplete_Or_Private_Kind))
4104 }
4109 /* Subprogram Entities
4111 The following access functions are defined for subprograms:
4113 Etype Return type or Standard_Void_Type.
4114 First_Formal The first formal parameter.
4115 Is_Imported Indicates that the subprogram has appeared in
4116 an INTERFACE or IMPORT pragma. For now we
4117 assume that the external language is C.
4118 Is_Exported Likewise but for an EXPORT pragma.
4119 Is_Inlined True if the subprogram is to be inlined.
4121 Each parameter is first checked by calling must_pass_by_ref on its
4122 type to determine if it is passed by reference. For parameters which
4123 are copied in, if they are Ada In Out or Out parameters, their return
4124 value becomes part of a record which becomes the return type of the
4125 function (C function - note that this applies only to Ada procedures
4126 so there is no Ada return type). Additional code to store back the
4127 parameters will be generated on the caller side. This transformation
4128 is done here, not in the front-end.
4130 The intended result of the transformation can be seen from the
4131 equivalent source rewritings that follow:
4133 struct temp {int a,b};
4134 procedure P (A,B: In Out ...) is temp P (int A,B)
4135 begin {
4136 .. ..
4137 end P; return {A,B};
4138 }
4140 temp t;
4141 P(X,Y); t = P(X,Y);
4142 X = t.a , Y = t.b;
4144 For subprogram types we need to perform mainly the same conversions to
4145 GCC form that are needed for procedures and function declarations. The
4146 only difference is that at the end, we make a type declaration instead
4147 of a function declaration. */
4152 {
4153 /* The type returned by a function or else Standard_Void_Type for a
4154 procedure. */
4156 tree gnu_return_type;
4157 /* The first GCC parameter declaration (a PARM_DECL node). The
4158 PARM_DECL nodes are chained through the DECL_CHAIN field, so this
4159 actually is the head of this parameter list. */
4161 /* Non-null for subprograms containing parameters passed by copy-in
4162 copy-out (Ada In Out or Out parameters not passed by reference),
4163 in which case it is the list of nodes used to specify the values
4164 of the In Out/Out parameters that are returned as a record upon
4165 procedure return. The TREE_PURPOSE of an element of this list is
4166 a field of the record and the TREE_VALUE is the PARM_DECL
4167 corresponding to that field. This list will be saved in the
4168 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
4170 /* List of fields in return type of procedure with copy-in copy-out
4171 parameters. */
4173 /* If an import pragma asks to map this subprogram to a GCC builtin,
4174 this is the builtin DECL node. */
4177 Entity_Id gnat_param;
4178 enum inline_status_t inline_status
4180 ? is_suppressed
4182 ? is_required
4185 /* Subprograms marked both Intrinsic and Always_Inline need not
4186 have a body of their own. */
4187 bool extern_flag
4189 || imported_p
4193 /* The semantics of "pure" in Ada essentially matches that of "const"
4194 in the back-end. In particular, both properties are orthogonal to
4195 the "nothrow" property if the EH circuitry is explicit in the
4196 internal representation of the back-end. If we are to completely
4197 hide the EH circuitry from it, we need to declare that calls to pure
4198 Ada subprograms that can throw have side effects since they can
4199 trigger an "abnormal" transfer of control flow; thus they can be
4200 neither "const" nor "pure" in the back-end sense. */
4201 bool const_flag
4210 /* A parameter may refer to this type, so defer completion of any
4211 incomplete types. */
4213 {
4214 defer_incomplete_level++;
4216 }
4218 /* If the subprogram has an alias, it is probably inherited, so
4219 we can use the original one. If the original "subprogram"
4220 is actually an enumeration literal, it may be the first use
4221 of its type, so we must elaborate that type now. */
4223 {
4229 /* Elaborate any Itypes in the parameters of this entity. */
4237 }
4239 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
4240 corresponding DECL node. Proper generation of calls later on need
4241 proper parameter associations so we don't "break;" here. */
4244 {
4247 /* Inability to find the builtin decl most often indicates a
4248 genuine mistake, but imports of unregistered intrinsics are
4249 sometimes issued on purpose to allow hooking in alternate
4250 bodies. We post a warning conditioned on Wshadow in this case,
4251 to let developers be notified on demand without risking false
4252 positives with common default sets of options. */
4256 }
4258 /* ??? What if we don't find the builtin node above ? warn ? err ?
4259 In the current state we neither warn nor err, and calls will just
4260 be handled as for regular subprograms. */
4262 /* Look into the return type and get its associated GCC tree. If it
4263 is not void, compute various flags for the subprogram type. */
4266 else
4267 {
4268 /* Ada 2012 (AI05-0151): Incomplete types coming from a limited
4269 context may now appear in parameter and result profiles. If
4270 we are only annotating types, break circularities here. */
4274 else
4277 /* If this function returns by reference, make the actual return
4278 type the pointer type and make a note of that. */
4280 {
4283 }
4285 /* If the return type is an unconstrained array type, the return
4286 value will be allocated on the secondary stack so the actual
4287 return type is the fat pointer type. */
4289 {
4292 }
4294 /* Likewise, if the return type requires a transient scope, the
4295 return value will also be allocated on the secondary stack so
4296 the actual return type is the pointer type. */
4298 {
4301 }
4303 /* If the Mechanism is By_Reference, ensure this function uses the
4304 target's by-invisible-reference mechanism, which may not be the
4305 same as above (e.g. it might be passing an extra parameter). */
4310 /* Likewise, if the return type is itself By_Reference. */
4314 /* If the type is a padded type and the underlying type would not
4315 be passed by reference or the function has a foreign convention,
4316 return the underlying type. */
4318 && (!default_pass_by_ref
4323 /* If the return type is unconstrained, that means it must have a
4324 maximum size. Use the padded type as the effective return type.
4325 And ensure the function uses the target's by-invisible-reference
4326 mechanism to avoid copying too much data when it returns. */
4328 {
4331 gnu_return_type
4337 /* Declare it now since it will never be declared otherwise.
4338 This is necessary to ensure that its subtrees are properly
4339 marked. */
4344 gnat_entity);
4347 }
4349 /* If the return type has a size that overflows, we cannot have
4350 a function that returns that type. This usage doesn't make
4351 sense anyway, so give an error here. */
4355 {
4357 gnat_entity);
4363 }
4364 }
4366 /* Loop over the parameters and get their associated GCC tree. While
4367 doing this, build a copy-in copy-out structure if we need one. */
4371 {
4378 /* Ada 2012 (AI05-0151): Incomplete types coming from a limited
4379 context may now appear in parameter and result profiles. If
4380 we are only annotating types, break circularities here. */
4383 {
4386 }
4387 else
4388 {
4391 }
4393 /* Builtins are expanded inline and there is no real call sequence
4394 involved. So the type expected by the underlying expander is
4395 always the type of each argument "as is". */
4398 /* Handle the first parameter of a valued procedure specially. */
4401 /* Otherwise, see if a Mechanism was supplied that forced this
4402 parameter to be passed one way or another. */
4406 ;
4408 {
4412 mech))
4414 else
4416 }
4417 else
4418 {
4421 }
4423 /* Do not call gnat_to_gnu_param for a fake parameter type since
4424 it will try to use the real type again. */
4426 {
4429 else
4430 {
4431 gnu_param
4438 }
4439 }
4440 else
4441 gnu_param
4446 /* We are returned either a PARM_DECL or a type if no parameter
4447 needs to be passed; in either case, adjust the type. */
4450 else
4451 {
4454 }
4456 /* The failure of this assertion will very likely come from an
4457 order of elaboration issue for the type of the parameter. */
4463 {
4469 /* If a parameter is a pointer, this function may modify
4470 memory through it and thus shouldn't be considered
4471 a const function. Also, the memory may be modified
4472 between two calls, so they can't be CSE'ed. The latter
4473 case also handles by-ref parameters. */
4477 }
4480 {
4482 {
4485 /* If this is a function, we also need a field for the
4486 return value to be placed. */
4488 {
4489 gnu_field
4491 gnu_return_type,
4497 gnu_cico_list
4499 }
4503 /* Set a default alignment to speed up accesses. But we
4504 shouldn't increase the size of the structure too much,
4505 lest it doesn't fit in return registers anymore. */
4508 }
4510 gnu_field
4518 gnu_cico_list
4520 }
4521 }
4524 {
4525 /* If we have a CICO list but it has only one entry, we convert
4526 this function into a function that returns this object. */
4530 /* Do not finalize the return type if the subprogram is stubbed
4531 since structures are incomplete for the back-end. */
4533 {
4537 /* Try to promote the mode of the return type if it is passed
4538 in registers, again to speed up accesses. */
4541 NULL_TREE))
4542 {
4543 unsigned int size
4546 machine_mode mode;
4552 {
4560 }
4561 }
4565 }
4566 }
4568 /* Deal with platform-specific calling conventions. */
4570 prepend_one_attribute
4573 gnat_entity);
4575 prepend_one_attribute
4578 gnat_entity);
4580 /* If we should request stack realignment for a foreign convention
4581 subprogram, do so. Note that this applies to task entry points
4582 in particular. */
4585 prepend_one_attribute
4588 gnat_entity);
4590 /* Deal with a pragma Linker_Section on a subprogram. */
4596 /* The lists have been built in reverse. */
4602 || return_by_direct_ref_p
4603 || return_by_invisi_ref_p
4605 gnu_type
4608 return_by_direct_ref_p,
4609 return_by_invisi_ref_p);
4611 /* A procedure (something that doesn't return anything) shouldn't be
4612 considered const since there would be no reason for calling such a
4613 subprogram. Note that procedures with Out (or In Out) parameters
4614 have already been converted into a function with a return type.
4615 Similarly, if the function returns an unconstrained type, then the
4616 function will allocate the return value on the secondary stack and
4617 thus calls to it cannot be CSE'ed, lest the stack be reclaimed. */
4622 {
4623 const int quals
4628 }
4630 /* If we have a builtin decl for that function, use it. Check if the
4631 profiles are compatible and warn if they are not. The checker is
4632 expected to post extra diagnostics in this case. */
4634 {
4635 intrin_binding_t inb;
4642 post_error
4644 gnat_entity);
4649 }
4651 /* If there was no specified Interface_Name and the external and
4652 internal names of the subprogram are the same, only use the
4653 internal name to allow disambiguation of nested subprograms. */
4658 /* If we are defining the subprogram and it has an Address clause
4659 we must get the address expression from the saved GCC tree for the
4660 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4661 the address expression here since the front-end has guaranteed
4662 in that case that the elaboration has no effects. If there is
4663 an Address clause and we are not defining the object, just
4664 make it a constant. */
4666 {
4670 gnu_address
4677 /* Convert the type of the object to a reference type that can
4678 alias everything as per 13.3(19). */
4679 gnu_type
4684 gnu_decl
4689 }
4692 {
4694 gnu_decl
4697 }
4698 else
4699 {
4700 gnu_decl
4705 /* This is unrelated to the stub built right above. */
4708 }
4709 }
4720 {
4721 /* Get the "full view" of this entity. If this is an incomplete
4722 entity from a limited with, treat its non-limited view as the
4723 full view. Otherwise, use either the full view or the underlying
4724 full view, whichever is present. This is used in all the tests
4725 below. */
4726 Entity_Id full_view
4735 /* If this is an incomplete type with no full view, it must be a Taft
4736 Amendment type, in which case we return a dummy type. Otherwise,
4737 just get the type from its Etype. */
4739 {
4741 {
4744 }
4745 else
4746 {
4750 }
4752 }
4754 /* If we already made a type for the full view, reuse it. */
4756 {
4759 }
4761 /* Otherwise, if we are not defining the type now, get the type
4762 from the full view. But always get the type from the full view
4763 for define on use types, since otherwise we won't see them! */
4767 {
4771 }
4773 /* For incomplete types, make a dummy type entry which will be
4774 replaced later. Save it as the full declaration's type so
4775 we can do any needed updates when we see it. */
4782 }
4785 /* Class-wide types are always transformed into their root type. */
4794 /* Concurrent types are always transformed into their record type. */
4797 else
4808 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4809 we've already saved it, so we don't try to. */
4815 /* This is a SPARK annotation that only reaches here when compiling in
4816 ASIS mode. */
4824 }
4826 /* If we had a case where we evaluated another type and it might have
4827 defined this one, handle it here. */
4829 {
4832 }
4834 /* If we are processing a type and there is either no decl for it or
4835 we just made one, do some common processing for the type, such as
4836 handling alignment and possible padding. */
4838 {
4839 /* Process the attributes, if not already done. Note that the type is
4840 already defined so we cannot pass true for IN_PLACE here. */
4843 /* Tell the middle-end that objects of tagged types are guaranteed to
4844 be properly aligned. This is necessary because conversions to the
4845 class-wide type are translated into conversions to the root type,
4846 which can be less aligned than some of its derived types. */
4851 /* Record whether the type is passed by reference. */
4855 /* ??? Don't set the size for a String_Literal since it is either
4856 confirming or we don't handle it properly (if the low bound is
4857 non-constant). */
4859 {
4862 gnu_size
4865 }
4867 /* If a size was specified, see if we can make a new type of that size
4868 by rearranging the type, for example from a fat to a thin pointer. */
4870 {
4871 gnu_type
4878 }
4880 /* If the alignment has not already been processed and this is not
4881 an unconstrained array type, see if an alignment is specified.
4882 If not, we pick a default alignment for atomic objects. */
4884 ;
4886 {
4890 /* Warn on suspiciously large alignments. This should catch
4891 errors about the (alignment,byte)/(size,bit) discrepancy. */
4893 {
4894 tree size;
4896 /* If a size was specified, take it into account. Otherwise
4897 use the RM size for records or unions as the type size has
4898 already been adjusted to the alignment. */
4904 else
4907 /* Consider an alignment as suspicious if the alignment/size
4908 ratio is greater or equal to the byte/bit ratio. */
4913 gnat_entity);
4914 }
4915 }
4926 /* See if we need to pad the type. If we did, and made a record,
4927 the name of the new type may be changed. So get it back for
4928 us when we make the new TYPE_DECL below. */
4936 /* Now set the RM size of the type. We cannot do it before padding
4937 because we need to accept arbitrary RM sizes on integral types. */
4940 /* If we are at global level, GCC will have applied variable_size to
4941 the type, but that won't have done anything. So, if it's not
4942 a constant or self-referential, call elaborate_expression_1 to
4943 make a variable for the size rather than calculating it each time.
4944 Handle both the RM size and the actual size. */
4949 {
4957 /* ??? For now, store the size as a multiple of the alignment in
4958 bytes so that we can see the alignment from the tree. */
4965 /* ??? gnu_type may come from an existing type so the MULT_EXPR node
4966 may not be marked by the call to create_type_decl below. */
4970 {
4975 {
4979 /* If the position of the variant part is constant, subtract
4980 it from the size of the type of the parent to get the new
4981 size. This manual CSE reduces the data size. */
4983 {
4991 }
4992 else
4993 {
4996 gnat_entity,
5000 /* ??? For now, store the size as a multiple of the
5001 alignment in bytes so that we can see the alignment
5002 from the tree. */
5005 gnat_entity,
5006 get_identifier
5011 /* ??? For now, store the offset as a multiple of the
5012 alignment in bytes so that we can see the alignment
5013 from the tree. */
5016 gnat_entity,
5019 DECL_OFFSET_ALIGN
5021 }
5025 }
5029 else
5030 ada_size
5035 }
5036 }
5038 /* If this is a record type or subtype, call elaborate_expression_2 on
5039 any field position. Do this for both global and local types.
5040 Skip any fields that we haven't made trees for to avoid problems with
5041 class wide types. */
5046 {
5049 /* ??? For now, store the offset as a multiple of the alignment
5050 in bytes so that we can see the alignment from the tree. */
5052 {
5055 gnat_temp,
5060 /* ??? The context of gnu_field is not necessarily gnu_type
5061 so the MULT_EXPR node built above may not be marked by
5062 the call to create_type_decl below. */
5065 }
5066 }
5071 /* If this is not an unconstrained array type, set some flags. */
5073 {
5082 }
5088 else
5089 {
5092 }
5093 }
5096 {
5099 /* If this is a derived type, relate its alias set to that of its parent
5100 to avoid troubles when a call to an inherited primitive is inlined in
5101 a context where a derived object is accessed. The inlined code works
5102 on the parent view so the resulting code may access the same object
5103 using both the parent and the derived alias sets, which thus have to
5104 conflict. As the same issue arises with component references, the
5105 parent alias set also has to conflict with composite types enclosing
5106 derived components. For instance, if we have:
5108 type D is new T;
5109 type R is record
5110 Component : D;
5111 end record;
5113 we want T to conflict with both D and R, in addition to R being a
5114 superset of D by record/component construction.
5116 One way to achieve this is to perform an alias set copy from the
5117 parent to the derived type. This is not quite appropriate, though,
5118 as we don't want separate derived types to conflict with each other:
5120 type I1 is new Integer;
5121 type I2 is new Integer;
5123 We want I1 and I2 to both conflict with Integer but we do not want
5124 I1 to conflict with I2, and an alias set copy on derivation would
5125 have that effect.
5127 The option chosen is to make the alias set of the derived type a
5128 superset of that of its parent type. It trivially fulfills the
5129 simple requirement for the Integer derivation example above, and
5130 the component case as well by superset transitivity:
5132 superset superset
5133 R ----------> D ----------> T
5135 However, for composite types, conversions between derived types are
5136 translated into VIEW_CONVERT_EXPRs so a sequence like:
5138 type Comp1 is new Comp;
5139 type Comp2 is new Comp;
5140 procedure Proc (C : Comp1);
5142 C : Comp2;
5143 Proc (Comp1 (C));
5145 is translated into:
5147 C : Comp2;
5148 Proc ((Comp1 &) &VIEW_CONVERT_EXPR <Comp1> (C));
5150 and gimplified into:
5152 C : Comp2;
5153 Comp1 *C.0;
5154 C.0 = (Comp1 *) &C;
5155 Proc (C.0);
5157 i.e. generates code involving type punning. Therefore, Comp1 needs
5158 to conflict with Comp2 and an alias set copy is required.
5160 The language rules ensure the parent type is already frozen here. */
5164 {
5166 /* For constrained packed array subtypes, the implementation type is
5167 used instead of the nominal type. */
5175 }
5177 /* Back-annotate the Alignment of the type if not already in the
5178 tree. Likewise for sizes. */
5180 {
5184 /* If the default alignment of "double" or larger scalar types is
5185 specifically capped and this is not an array with an alignment
5186 clause on the component type, return the cap. */
5188 is_capped_double
5191 is_capped_double
5193 else
5198 else
5202 }
5205 {
5208 /* If the size is self-referential, annotate the maximum value. */
5212 /* If we are just annotating types and the type is tagged, the tag
5213 and the parent components are not generated by the front-end so
5214 sizes must be adjusted if there is no representation clause. */
5220 {
5222 Uint uint_size;
5225 {
5229 }
5230 else
5234 offset
5242 }
5243 else
5245 }
5249 }
5251 /* If we really have a ..._DECL node, set a couple of flags on it. But we
5252 cannot do so if we are reusing the ..._DECL node made for an equivalent
5253 type or an alias or a renamed object as the predicates don't apply to it
5254 but to GNAT_ENTITY. */
5259 {
5265 }
5267 /* If we haven't already, associate the ..._DECL node that we just made with
5268 the input GNAT entity node. */
5272 /* Now we are sure gnat_entity has a corresponding ..._DECL node,
5273 eliminate as many deferred computations as possible. */
5276 /* If this is an enumeration or floating-point type, we were not able to set
5277 the bounds since they refer to the type. These are always static. */
5280 {
5284 /* If this is a padded type, we need to use the underlying type. */
5288 /* If this is a floating point type and we haven't set a floating
5289 point type yet, use this in the evaluation of the bounds. */
5297 {
5298 /* Enumeration types have specific RM bounds. */
5301 }
5302 else
5303 {
5304 /* Floating-point types don't have specific RM bounds. */
5307 }
5308 }
5310 /* If we deferred processing of incomplete types, re-enable it. If there
5311 were no other disables and we have deferred types to process, do so. */
5315 {
5318 /* We are back to level 0 for the deferring of incomplete types.
5319 But processing these incomplete types below may itself require
5320 deferring, so preserve what we have and restart from scratch. */
5325 {
5332 }
5333 }
5335 /* If we are not defining this type, see if it's on one of the lists of
5336 incomplete types. If so, handle the list entry now. */
5338 {
5343 {
5347 }
5351 {
5355 }
5356 }
5359 force_global--;
5361 /* If this is a packed array type whose original array type is itself
5362 an Itype without freeze node, make sure the latter is processed. */
5370 }
5372 /* Similar, but if the returned value is a COMPONENT_REF, return the
5373 FIELD_DECL. */
5375 tree
5377 {
5384 }
5386 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5387 the GCC type corresponding to that entity. */
5389 tree
5391 {
5392 tree gnu_decl;
5394 /* The back end never attempts to annotate generic types. */
5402 }
5404 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5405 the unpadded version of the GCC type corresponding to that entity. */
5407 tree
5409 {
5416 }
5418 /* Return the DECL associated with the public subprogram GNAT_ENTITY but whose
5419 type has been changed to that of the parameterless procedure, except if an
5420 alias is already present, in which case it is returned instead. */
5422 tree
5424 {
5428 /* See the E_Function/E_Procedure case of gnat_to_gnu_entity for the model
5429 of the handling applied here. */
5432 {
5436 }
5444 gnat_entity);
5448 gnat_entity);
5453 return
5456 }
5458 /* Return whether the E_Subprogram_Type/E_Function/E_Procedure GNAT_ENTITY is
5459 a C++ imported method or equivalent.
5461 We use the predicate on 32-bit x86/Windows to find out whether we need to
5462 use the "thiscall" calling convention for GNAT_ENTITY. This convention is
5463 used for C++ methods (functions with METHOD_TYPE) by the back-end. */
5465 bool
5467 {
5471 /* This is the main case: C++ method imported as a primitive operation.
5472 Note that a C++ class with no virtual functions can be imported as a
5473 limited record type so the operation is not necessarily dispatching. */
5477 /* A thunk needs to be handled like its associated primitive operation. */
5481 /* A constructor is a method on the C++ side. */
5485 /* This is set on the E_Subprogram_Type built for a dispatching call. */
5490 }
5492 /* Finalize the processing of From_Limited_With incomplete types. */
5494 void
5496 {
5503 {
5510 }
5511 }
5513 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
5514 kind of type (such E_Task_Type) that has a different type which Gigi
5515 uses for its representation. If the type does not have a special type
5516 for its representation, return GNAT_ENTITY. If a type is supposed to
5517 exist, but does not, abort unless annotating types, in which case
5518 return Empty. If GNAT_ENTITY is Empty, return Empty. */
5520 Entity_Id
5522 {
5529 {
5553 }
5558 }
5560 /* Return a GCC tree for a type corresponding to the component type of the
5561 array type or subtype GNAT_ARRAY. DEFINITION is true if this component
5562 is for an array being defined. DEBUG_INFO_P is true if we need to write
5563 debug information for other types that we may create in the process. */
5565 static tree
5568 {
5571 tree gnu_comp_size;
5573 /* Try to get a smaller form of the component if needed. */
5587 /* Get and validate any specified Component_Size. */
5588 gnu_comp_size
5593 /* If the array has aliased components and the component size can be zero,
5594 force at least unit size to ensure that the components have distinct
5595 addresses. */
5601 gnu_comp_size
5604 /* If the component type is a RECORD_TYPE that has a self-referential size,
5605 then use the maximum size for the component size. */
5611 /* Honor the component size. This is not needed for bit-packed arrays. */
5613 {
5617 /* If an alignment is specified, use it as a cap on the component type
5618 so that it can be honored for the whole type. But ignore it for the
5619 original type of packed array types. */
5623 else
5629 else
5635 /* If a padding record was made, declare it now since it will never be
5636 declared otherwise. This is necessary to ensure that its subtrees
5637 are properly marked. */
5640 gnat_array);
5641 }
5643 /* If the component type is a padded type made for a non-bit-packed array
5644 of scalars with reverse storage order, we need to propagate the reverse
5645 storage order to the padding type since it is the innermost enclosing
5646 aggregate type around the scalar. */
5657 }
5659 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
5660 using MECH as its passing mechanism, to be placed in the parameter
5661 list built for GNAT_SUBPROG. Assume a foreign convention for the
5662 latter if FOREIGN is true. Also set CICO to true if the parameter
5663 must use the copy-in copy-out implementation mechanism.
5665 The returned tree is a PARM_DECL, except for those cases where no
5666 parameter needs to be actually passed to the subprogram; the type
5667 of this "shadow" parameter is then returned instead. */
5669 static tree
5672 {
5676 /* The parameter can be indirectly modified if its address is taken. */
5680 tree gnu_param;
5682 /* Copy-return is used only for the first parameter of a valued procedure.
5683 It's a copy mechanism for which a parameter is never allocated. */
5685 {
5689 }
5691 /* If this is either a foreign function or if the underlying type won't
5692 be passed by reference and is as aligned as the original type, strip
5693 off possible padding type. */
5695 {
5704 }
5706 /* If this is a read-only parameter, make a variant of the type that is
5707 read-only. ??? However, if this is an unconstrained array, that type
5708 can be very complex, so skip it for now. Likewise for any other
5709 self-referential type. */
5715 /* For foreign conventions, pass arrays as pointers to the element type.
5716 First check for unconstrained array and get the underlying array. */
5718 gnu_param_type
5721 /* For GCC builtins, pass Address integer types as (void *) */
5727 /* Arrays are passed as pointers to element type for foreign conventions. */
5729 {
5730 /* Strip off any multi-dimensional entries, then strip
5731 off the last array to get the component type. */
5740 gnu_param_type
5744 }
5746 /* Fat pointers are passed as thin pointers for foreign conventions. */
5748 gnu_param_type
5751 /* If we must pass or were requested to pass by reference, do so.
5752 If we were requested to pass by copy, do so.
5753 Otherwise, for foreign conventions, pass In Out or Out parameters
5754 or aggregates by reference. For COBOL and Fortran, pass all
5755 integer and FP types that way too. For Convention Ada, use
5756 the standard Ada default. */
5760 && ((foreign
5762 || (foreign
5767 || (!foreign
5769 {
5770 /* We take advantage of 6.2(12) by considering that references built for
5771 parameters whose type isn't by-ref and for which the mechanism hasn't
5772 been forced to by-ref are restrict-qualified in the C sense. */
5773 bool restrict_p
5777 gnu_param_type
5780 }
5782 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
5789 /* If this is an Out parameter that isn't passed by reference and isn't
5790 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
5791 it will be a VAR_DECL created when we process the procedure, so just
5792 return its type. For the special parameter of a valued procedure,
5793 never pass it in.
5795 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
5796 Out parameters with discriminants or implicit initial values to be
5797 handled like In Out parameters. These type are normally built as
5798 aggregates, hence passed by reference, except for some packed arrays
5799 which end up encoded in special integer types. Note that scalars can
5800 be given implicit initial values using the Default_Value aspect.
5802 The exception we need to make is then for packed arrays of records
5803 with discriminants or implicit initial values. We have no light/easy
5804 way to check for the latter case, so we merely check for packed arrays
5805 of records. This may lead to useless copy-in operations, but in very
5806 rare cases only, as these would be exceptions in a set of already
5807 exceptional situations. */
5809 && !by_ref
5810 && (by_return
5827 /* If no Mechanism was specified, indicate what we're using, then
5828 back-annotate it. */
5834 }
5836 /* Return true if GNAT_ENTITY is an incomplete entity coming from a limited
5837 with of the main unit and whose full view has not been elaborated yet. */
5839 static bool
5841 {
5842 /* Class-wide types are always transformed into their root type. */
5848 {
5855 }
5858 }
5860 /* Like build_qualified_type, but TYPE_QUALS is added to the existing
5861 qualifiers on TYPE. */
5863 static tree
5865 {
5867 }
5869 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
5871 static bool
5873 {
5880 return
5882 }
5884 /* Return true if the array type GNU_TYPE, which represents a dimension of
5885 GNAT_TYPE, has a non-aliased component in the back-end sense. */
5887 static bool
5889 {
5890 /* If the array type is not the innermost dimension of the GNAT type,
5891 then it has a non-aliased component. */
5896 /* If the array type has an aliased component in the front-end sense,
5897 then it also has an aliased component in the back-end sense. */
5901 /* If this is a derived type, then it has a non-aliased component if
5902 and only if its parent type also has one. */
5904 {
5908 gnu_parent_type
5913 }
5915 /* Otherwise, rely exclusively on properties of the element type. */
5917 }
5919 /* Return true if GNAT_ADDRESS is a value known at compile-time. */
5921 static bool
5923 {
5924 /* Catch System'To_Address. */
5929 }
5931 /* Return true if GNAT_RANGE, a N_Range node, cannot be superflat, i.e. if the
5932 inequality HB >= LB-1 is true. LB and HB are the low and high bounds. */
5934 static bool
5936 {
5938 Node_Id scalar_range;
5941 /* If the low bound is not constant, try to find an upper bound. */
5950 /* If the high bound is not constant, try to find a lower bound. */
5959 /* If we have failed to find constant bounds, punt. */
5964 /* We need at least a signed 64-bit type to catch most cases. */
5970 /* If the low bound is the smallest integer, nothing can be smaller. */
5976 }
5978 /* Return true if GNU_EXPR is (essentially) the address of a CONSTRUCTOR. */
5980 static bool
5982 {
5990 }
5991 \f
5992 /* Given GNAT_ENTITY, elaborate all expressions that are required to
5993 be elaborated at the point of its definition, but do nothing else. */
5995 void
5997 {
5999 {
6006 {
6010 /* ??? Tests to avoid Constraint_Error in static expressions
6011 are needed until after the front stops generating bogus
6012 conversions on bounds of real types. */
6020 }
6027 {
6028 Node_Id gnat_discriminant_expr;
6029 Entity_Id gnat_field;
6033 gnat_discriminant_expr
6038 /* Ignore access discriminants. */
6043 }
6046 }
6047 }
6048 \f
6049 /* Return true if the size in units represented by GNU_SIZE can be handled by
6050 an allocation. If STATIC_P is true, consider only what can be done with a
6051 static allocation. */
6053 static bool
6055 {
6056 /* We can allocate a fixed size if it is a valid for the middle-end. */
6060 /* We can allocate a variable size if this isn't a static allocation. */
6061 else
6063 }
6064 \f
6065 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
6066 NAME, ARGS and ERROR_POINT. */
6068 static void
6071 tree attr_name,
6072 tree attr_args,
6073 Node_Id attr_error_point)
6074 {
6084 }
6086 /* Prepend to ATTR_LIST an entry for an attribute provided by GNAT_PRAGMA. */
6088 static void
6090 {
6095 /* Map the pragma at hand. Skip if this isn't one we know how to handle. */
6097 {
6128 }
6130 /* See what arguments we have and turn them into GCC trees for attribute
6131 handlers. These expect identifier for strings. We handle at most two
6132 arguments and static expressions only. */
6134 {
6140 {
6144 {
6148 }
6151 }
6155 {
6160 }
6161 }
6163 /* Prepend to the list. Make a list of the argument we might have, as GCC
6164 expects it. */
6166 gnu_arg1
6170 }
6172 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
6174 static void
6176 {
6177 Node_Id gnat_temp;
6179 /* Attributes are stored as Representation Item pragmas. */
6185 }
6186 \f
6187 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
6188 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
6189 return the GCC tree to use for that expression. GNU_NAME is the suffix
6190 to use if a variable needs to be created and DEFINITION is true if this
6191 is a definition of GNAT_ENTITY. If NEED_VALUE is true, we need a result;
6192 otherwise, we are just elaborating the expression for side-effects. If
6193 NEED_DEBUG is true, we need a variable for debugging purposes even if it
6194 isn't needed for code generation. */
6196 static tree
6199 {
6200 tree gnu_expr;
6202 /* If we already elaborated this expression (e.g. it was involved
6203 in the definition of a private type), use the old value. */
6207 /* If we don't need a value and this is static or a discriminant,
6208 we don't need to do anything. */
6215 /* If it's a static expression, we don't need a variable for debugging. */
6219 /* Otherwise, convert this tree to its GCC equivalent and elaborate it. */
6223 /* Save the expression in case we try to elaborate this entity again. Since
6224 it's not a DECL, don't check it. Don't save if it's a discriminant. */
6229 }
6231 /* Similar, but take a GNU expression and always return a result. */
6233 static tree
6236 {
6241 /* In most cases, we won't see a naked FIELD_DECL because a discriminant
6242 reference will have been replaced with a COMPONENT_REF when the type
6243 is being elaborated. However, there are some cases involving child
6244 types where we will. So convert it to a COMPONENT_REF. We hope it
6245 will be at the highest level of the expression in these cases. */
6251 /* If GNU_EXPR contains a placeholder, just return it. We rely on the fact
6252 that an expression cannot contain both a discriminant and a variable. */
6256 /* If GNU_EXPR is neither a constant nor based on a read-only variable, make
6257 a variable that is initialized to contain the expression when the package
6258 containing the definition is elaborated. If this entity is defined at top
6259 level, replace the expression by the variable; otherwise use a SAVE_EXPR
6260 if this is necessary. */
6263 else
6264 {
6265 /* Skip any conversions and simple constant arithmetics to see if the
6266 expression is based on a read-only variable.
6267 ??? This really should remain read-only, but we have to think about
6268 the typing of the tree here. */
6274 {
6276 tree offset;
6277 machine_mode mode;
6280 inner
6283 /* If the offset is variable, err on the side of caution. */
6286 }
6288 expr_variable_p
6289 = !(inner
6292 }
6294 /* We only need to use the variable if we are in a global context since GCC
6295 can do the right thing in the local case. However, when not optimizing,
6296 use it for bounds of loop iteration scheme to avoid code duplication. */
6297 use_variable = expr_variable_p
6298 && (expr_global_p
6299 || (!optimize
6300 && definition
6305 /* Now create it, possibly only for debugging purposes. */
6307 {
6308 /* The following variable creation can happen when processing the body of
6309 subprograms that are defined out of the extended main unit and
6310 inlined. In this case, we are not at the global scope, and thus the
6311 new variable must not be tagged "external", as we used to do here as
6312 long as definition == 0. */
6314 tree gnu_decl
6315 = create_var_decl_1
6322 /* Using this variable at debug time (if need_debug is true) requires a
6323 proper location. The back-end will compute a location for this
6324 variable only if the variable is used by the generated code.
6325 Returning the variable ensures the caller will use it in generated
6326 code. Note that there is no need for a location if the debug info
6327 contains an integer constant.
6328 FIXME: when the encoding-based debug scheme is dropped, move this
6329 condition to the top-level IF block: we will not need to create a
6330 variable anymore in such cases, then. */
6333 }
6336 }
6338 /* Similar, but take an alignment factor and make it explicit in the tree. */
6340 static tree
6343 {
6345 return
6348 gnu_expr,
6349 unit_align),
6351 need_debug),
6352 unit_align);
6353 }
6354 \f
6355 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
6356 the value passed against the list of choices. */
6358 tree
6360 {
6361 Node_Id choice;
6362 Node_Id gnat_temp;
6367 {
6369 {
6374 this_test
6388 this_test
6398 /* This represents either a subtype range, an enumeration
6399 literal, or a constant Ekind says which. If an enumeration
6400 literal or constant, fall through to the next case. */
6403 {
6409 this_test
6416 }
6418 /* ... fall through ... */
6424 single);
6433 }
6436 this_test);
6437 }
6440 }
6441 \f
6442 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
6443 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
6445 static int
6447 {
6448 /* If the field contains an item of variable size, we cannot pack it
6449 because we cannot create temporaries of non-fixed size in case
6450 we need to take the address of the field. See addressable_p and
6451 the notes on the addressability issues for further details. */
6455 /* If the alignment of the record is specified and the field type
6456 is over-aligned, request Storage_Unit alignment for the field. */
6458 {
6461 else
6463 }
6466 }
6468 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
6469 placed in GNU_RECORD_TYPE.
6471 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
6472 record has Component_Alignment of Storage_Unit, -2 if the enclosing
6473 record has a specified alignment.
6475 DEFINITION is true if this field is for a record being defined.
6477 DEBUG_INFO_P is true if we need to write debug information for types
6478 that we may create in the process. */
6480 static tree
6483 {
6485 const bool is_aliased
6487 const bool is_atomic
6489 const bool is_independent
6491 const bool is_volatile
6493 const bool needs_strict_alignment
6494 = (is_aliased
6495 || is_independent
6496 || is_volatile
6502 /* If this field requires strict alignment, we cannot pack it because
6503 it would very likely be under-aligned in the record. */
6506 else
6509 /* If a size is specified, use it. Otherwise, if the record type is packed,
6510 use the official RM size. See "Handling of Type'Size Values" in Einfo
6511 for further details. */
6518 else
6521 /* If we have a specified size that is smaller than that of the field's type,
6522 or a position is specified, and the field's type is a record that doesn't
6523 require strict alignment, see if we can get either an integral mode form
6524 of the type or a smaller form. If we can, show a size was specified for
6525 the field if there wasn't one already, so we know to make this a bitfield
6526 and avoid making things wider.
6528 Changing to an integral mode form is useful when the record is packed as
6529 we can then place the field at a non-byte-aligned position and so achieve
6530 tighter packing. This is in addition required if the field shares a byte
6531 with another field and the front-end lets the back-end handle the access
6532 to the field, because GCC cannot handle non-byte-aligned BLKmode fields.
6534 Changing to a smaller form is required if the specified size is smaller
6535 than that of the field's type and the type contains sub-fields that are
6536 padded, in order to avoid generating accesses to these sub-fields that
6537 are wider than the field.
6539 We avoid the transformation if it is not required or potentially useful,
6540 as it might entail an increase of the field's alignment and have ripple
6541 effects on the outer record type. A typical case is a field known to be
6542 byte-aligned and not to share a byte with another field. */
6548 || (gnu_size
6554 {
6557 {
6561 }
6562 }
6568 {
6570 Entity_Id gnat_parent
6577 /* Ensure the position does not overlap with the parent subtype, if there
6578 is one. This test is omitted if the parent of the tagged type has a
6579 full rep clause since, in this case, component clauses are allowed to
6580 overlay the space allocated for the parent type and the front-end has
6581 checked that there are no overlapping components. */
6583 {
6588 post_error_ne_tree
6591 }
6593 /* If this field needs strict alignment, make sure that the record is
6594 sufficiently aligned and that the position and size are consistent
6595 with the type. But don't do it if we are just annotating types and
6596 the field's type is tagged, since tagged types aren't fully laid out
6597 in this mode. Also, note that atomic implies volatile so the inner
6598 test sequences ordering is significant here. */
6601 {
6607 /* If the position is not a multiple of the alignment of the type,
6608 then error out and reset the position. */
6611 {
6625 else
6629 type_align);
6631 }
6634 {
6638 /* If the size is lower than that of the type, or greater for
6639 atomic and aliased, then error out and reset the size. */
6641 {
6655 else
6659 gnu_type_size);
6661 }
6663 /* Likewise if the size is not a multiple of a byte, */
6665 bitsize_unit_node)))
6666 {
6678 else
6683 }
6684 }
6685 }
6686 }
6688 /* If the record has rep clauses and this is the tag field, make a rep
6689 clause for it as well. */
6692 {
6695 }
6697 else
6698 {
6701 /* If we are packing the record and the field is BLKmode, round the
6702 size up to a byte boundary. */
6705 }
6707 /* We need to make the size the maximum for the type if it is
6708 self-referential and an unconstrained type. In that case, we can't
6709 pack the field since we can't make a copy to align it. */
6711 && !gnu_size
6714 {
6717 }
6719 /* If a size is specified, adjust the field's type to it. */
6721 {
6722 tree orig_field_type;
6724 /* If the field's type is justified modular, we would need to remove
6725 the wrapper to (better) meet the layout requirements. However we
6726 can do so only if the field is not aliased to preserve the unique
6727 layout and if the prescribed size is not greater than that of the
6728 packed array to preserve the justification. */
6736 /* Similarly if the field's type is a misaligned integral type, but
6737 there is no restriction on the size as there is no justification. */
6743 gnu_field_type
6751 /* If a padding record was made, declare it now since it will never be
6752 declared otherwise. This is necessary to ensure that its subtrees
6753 are properly marked. */
6758 }
6760 /* Otherwise (or if there was an error), don't specify a position. */
6761 else
6764 /* If the field's type is a padded type made for a scalar field of a record
6765 type with reverse storage order, we need to propagate the reverse storage
6766 order to the padding type since it is the innermost enclosing aggregate
6767 type around the scalar. */
6776 /* Now create the decl for the field. */
6777 gnu_field
6789 }
6790 \f
6791 /* Return true if at least one member of COMPONENT_LIST needs strict
6792 alignment. */
6794 static bool
6796 {
6797 Node_Id component_decl;
6802 {
6810 }
6813 }
6815 /* Return true if TYPE is a type with variable size or a padding type with a
6816 field of variable size or a record that has a field with such a type. */
6818 static bool
6820 {
6821 tree field;
6838 }
6839 \f
6840 /* Return true if FIELD is an artificial field. */
6842 static bool
6844 {
6845 /* These fields are generated by the front-end proper. */
6849 /* These fields are generated by gigi. */
6854 }
6856 /* Return true if FIELD is a non-artificial aliased field. */
6858 static bool
6860 {
6865 }
6867 /* Return true if FIELD is a non-artificial field with self-referential
6868 size. */
6870 static bool
6872 {
6880 }
6882 /* Return true if FIELD is a non-artificial field with variable size. */
6884 static bool
6886 {
6894 }
6896 /* qsort comparer for the bit positions of two record components. */
6898 static int
6900 {
6903 const int ret
6907 }
6909 /* Structure holding information for a given variant. */
6911 {
6912 /* The record type of the variant. */
6913 tree type;
6915 /* The name of the variant. */
6916 tree name;
6918 /* The qualifier of the variant. */
6919 tree qual;
6921 /* Whether the variant has a rep clause. */
6924 /* Whether the variant is packed. */
6929 /* Translate and chain the GNAT_COMPONENT_LIST to the GNU_FIELD_LIST, set the
6930 result as the field list of GNU_RECORD_TYPE and finish it up. Return true
6931 if GNU_RECORD_TYPE has a rep clause which affects the layout (see below).
6932 When called from gnat_to_gnu_entity during the processing of a record type
6933 definition, the GCC node for the parent, if any, will be the single field
6934 of GNU_RECORD_TYPE and the GCC nodes for the discriminants will be on the
6935 GNU_FIELD_LIST. The other calls to this function are recursive calls for
6936 the component list of a variant and, in this case, GNU_FIELD_LIST is empty.
6938 PACKED is 1 if this is for a packed record, -1 if this is for a record
6939 with Component_Alignment of Storage_Unit, -2 if this is for a record
6940 with a specified alignment.
6942 DEFINITION is true if we are defining this record type.
6944 CANCEL_ALIGNMENT is true if the alignment should be zeroed before laying
6945 out the record. This means the alignment only serves to force fields to
6946 be bitfields, but not to require the record to be that aligned. This is
6947 used for variants.
6949 ALL_REP is true if a rep clause is present for all the fields.
6951 UNCHECKED_UNION is true if we are building this type for a record with a
6952 Pragma Unchecked_Union.
6954 ARTIFICIAL is true if this is a type that was generated by the compiler.
6956 DEBUG_INFO is true if we need to write debug information about the type.
6958 MAYBE_UNUSED is true if this type may be unused in the end; this doesn't
6959 mean that its contents may be unused as well, only the container itself.
6961 REORDER is true if we are permitted to reorder components of this type.
6963 FIRST_FREE_POS, if nonzero, is the first (lowest) free field position in
6964 the outer record type down to this variant level. It is nonzero only if
6965 all the fields down to this level have a rep clause and ALL_REP is false.
6967 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
6968 with a rep clause is to be added; in this case, that is all that should
6969 be done with such fields and the return value will be false. */
6971 static bool
6978 {
6992 /* For each component referenced in a component declaration create a GCC
6993 field and add it to the list, skipping pragmas in the GNAT list. */
7000 {
7004 /* If present, the _Parent field must have been created as the single
7005 field of the record type. Put it before any other fields. */
7007 {
7010 }
7011 else
7012 {
7016 /* If this is the _Tag field, put it before any other fields. */
7020 /* If this is the _Controller field, put it before the other
7021 fields except for the _Tag or _Parent field. */
7023 {
7026 }
7028 /* If this is a regular field, put it after the other fields. */
7029 else
7030 {
7036 /* And record information for the final layout. */
7041 }
7042 }
7045 }
7047 /* At the end of the component list there may be a variant part. */
7050 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
7051 mutually exclusive and should go in the same memory. To do this we need
7052 to treat each variant as a record whose elements are created from the
7053 component list for the variant. So here we create the records from the
7054 lists for the variants and put them all into the QUAL_UNION_TYPE.
7055 If this is an Unchecked_Union, we make a UNION_TYPE instead or
7056 use GNU_RECORD_TYPE if there are no fields so far. */
7058 {
7062 tree gnu_var_name
7073 gnu_union_name
7076 /* Reuse the enclosing union if this is an Unchecked_Union whose fields
7077 are all in the variant part, to match the layout of C unions. There
7078 is an associated check below. */
7081 else
7082 {
7083 gnu_union_type
7091 }
7093 /* If all the fields down to this level have a rep clause, find out
7094 whether all the fields at this level also have one. If so, then
7095 compute the new first free position to be passed downward. */
7098 {
7100 gnu_field;
7103 {
7106 this_first_free_pos
7108 }
7109 else
7110 {
7113 }
7114 }
7116 /* We build the variants in two passes. The bulk of the work is done in
7117 the first pass, that is to say translating the GNAT nodes, building
7118 the container types and computing the associated properties. However
7119 we cannot finish up the container types during this pass because we
7120 don't know where the variant part will be placed until the end. */
7124 {
7129 vinfo_t vinfo;
7137 /* Set the alignment of the inner type in case we need to make
7138 inner objects into bitfields, but then clear it out so the
7139 record actually gets only the alignment required. */
7145 /* Similarly, if the outer record has a size specified and all
7146 the fields have a rep clause, we can propagate the size. */
7148 {
7152 }
7154 /* Add the fields into the record type for the variant. Note that
7155 we aren't sure to really use it at this point, see below. */
7156 has_rep
7160 unchecked_union,
7162 this_first_free_pos,
7163 all_rep || this_first_free_pos
7166 /* Translate the qualifier and annotate the GNAT node. */
7170 /* Deal with packedness like in gnat_to_gnu_field. */
7172 {
7175 }
7176 else
7177 field_packed
7180 /* Push this variant onto the stack for the second pass. */
7188 /* Compute the global properties that will determine the placement of
7189 the variant part. */
7193 }
7195 /* Round up the first free position to the alignment of the variant part
7196 for the variants without rep clause. This will guarantee a consistent
7197 layout independently of the placement of the variant part. */
7201 /* In the second pass, the container types are adjusted if necessary and
7202 finished up, then the corresponding fields of the variant part are
7203 built with their qualifier, unless this is an unchecked union. */
7205 {
7209 /* If this is an Unchecked_Union whose fields are all in the variant
7210 part and we have a single field with no representation clause or
7211 placed at offset zero, use the field directly to match the layout
7212 of C unions. */
7214 && gnu_field_list
7218 {
7221 }
7222 else
7223 {
7224 /* Finalize the variant type now. We used to throw away empty
7225 record types but we no longer do that because we need them to
7226 generate complete debug info for the variant; otherwise, the
7227 union type definition will be lacking the fields associated
7228 with these empty variants. */
7230 {
7231 /* The variant part will be at offset 0 so we need to ensure
7232 that the fields are laid out starting from the first free
7233 position at this level. */
7235 tree gnu_rep_part;
7239 gnu_rep_part
7241 this_first_free_pos);
7246 }
7253 gnu_field
7255 gnu_union_type,
7256 all_rep_and_size
7265 }
7269 }
7271 /* Only make the QUAL_UNION_TYPE if there are non-empty variants. */
7273 {
7277 {
7281 }
7286 /* If GNU_UNION_TYPE is our record type, it means we must have an
7287 Unchecked_Union with no fields. Verify that and, if so, just
7288 return. */
7290 {
7292 && !gnu_field_list
7295 }
7300 /* Deal with packedness like in gnat_to_gnu_field. */
7303 else
7304 union_field_packed
7307 gnu_variant_part
7309 all_rep_and_size
7315 }
7316 }
7318 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses and, if we are
7319 permitted to reorder components, self-referential sizes or variable sizes.
7320 If they do, pull them out and put them onto the appropriate list. We have
7321 to do this in a separate pass since we want to handle the discriminants
7322 but can't play with them until we've used them in debugging data above.
7324 Similarly, pull out the fields with zero size and no rep clause, as they
7325 would otherwise modify the layout and thus very likely run afoul of the
7326 Ada semantics, which are different from those of C here.
7328 ??? If we reorder them, debugging information will be wrong but there is
7329 nothing that can be done about this at the moment. */
7332 #define MOVE_FROM_FIELD_LIST_TO(LIST) \
7333 do { \
7334 if (gnu_last) \
7335 DECL_CHAIN (gnu_last) = gnu_next; \
7336 else \
7337 gnu_field_list = gnu_next; \
7338 \
7339 DECL_CHAIN (gnu_field) = (LIST); \
7340 (LIST) = gnu_field; \
7341 } while (0)
7344 {
7348 {
7351 }
7355 {
7358 }
7361 {
7364 }
7367 {
7377 }
7380 }
7382 #undef MOVE_FROM_FIELD_LIST_TO
7386 /* If permitted, we reorder the fields as follows:
7388 1) all fixed length fields,
7389 2) all fields whose length doesn't depend on discriminants,
7390 3) all fields whose length depends on discriminants,
7391 4) the variant part,
7393 within the record and within each variant recursively. */
7395 gnu_field_list
7398 /* Otherwise, if there is an aliased field placed after a field whose length
7399 depends on discriminants, we put all the fields of the latter sort, last.
7400 We need to do this in case an object of this record type is mutable. */
7404 /* If P_REP_LIST is nonzero, this means that we are asked to move the fields
7405 in our REP list to the previous level because this level needs them in
7406 order to do a correct layout, i.e. avoid having overlapping fields. */
7410 /* Otherwise, sort the fields by bit position and put them into their own
7411 record, before the others, if we also have fields without rep clause. */
7413 {
7418 /* If all the fields have a rep clause, we can do a flat layout. */
7419 layout_with_rep = !gnu_field_list
7421 gnu_rep_type
7425 gnu_field;
7431 /* Put the fields in the list in order of increasing position, which
7432 means we start from the end. */
7435 {
7439 }
7443 else
7444 {
7449 /* If FIRST_FREE_POS is nonzero, we need to ensure that the fields
7450 without rep clause are laid out starting from this position.
7451 Therefore, we force it as a minimal size on the REP part. */
7452 gnu_rep_part
7455 /* Chain the REP part at the beginning of the field list. */
7458 }
7459 }
7461 /* Chain the variant part at the end of the field list. */
7473 /* Chain the fields with zero size at the beginning of the field list. */
7479 }
7480 \f
7481 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
7482 placed into an Esize, Component_Bit_Offset, or Component_Size value
7483 in the GNAT tree. */
7485 static Uint
7487 {
7488 TCode tcode;
7493 /* See if we've already saved the value for this node. */
7495 {
7503 }
7504 else
7507 /* If we do not return inside this switch, TCODE will be set to the
7508 code to use for a Create_Node operand and LEN (set above) will be
7509 the number of recursive calls for us to make. */
7512 {
7517 /* The only case we handle here is a simple discriminant reference. */
7519 {
7522 /* Climb up the chain of successive extensions, if any. */
7529 return
7531 }
7538 /* Now just list the operations we handle. */
7569 /* For negative values in sizetype, build NEGATE_EXPR of the opposite.
7570 Such values appear in expressions with aligning patterns. Note that,
7571 since sizetype is unsigned, we have to jump through some hoops. */
7573 {
7577 {
7580 }
7581 }
7585 /* In regular mode, inline back only if symbolic annotation is requested
7586 in order to avoid memory explosion on big discriminated record types.
7587 But not in ASIS mode, as symbolic annotation is required for DDA. */
7589 {
7593 }
7594 else
7597 /* Fall through... */
7601 }
7603 /* Now get each of the operands that's relevant for this code. If any
7604 cannot be expressed as a repinfo node, say we can't. */
7609 {
7612 else
7616 }
7620 /* Save the result in the cache. */
7622 {
7624 /* We can't assume the hash table data hasn't moved since the initial
7625 look up, so we have to search again. Allocating and inserting an
7626 entry at that point would be an alternative, but then we'd better
7627 discard the entry if we decided not to cache it. */
7633 }
7636 }
7638 /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
7639 and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
7640 size and alignment used by Gigi. Prefer SIZE over TYPE_SIZE if non-null.
7641 BY_REF is true if the object is used by reference. */
7643 void
7645 {
7647 {
7650 else
7652 }
7655 {
7664 }
7669 }
7671 /* Return first element of field list whose TREE_PURPOSE is the same as ELEM.
7672 Return NULL_TREE if there is no such element in the list. */
7674 static tree
7676 {
7678 {
7683 }
7685 }
7687 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding GCC type,
7688 set Component_Bit_Offset and Esize of the components to the position and
7689 size used by Gigi. */
7691 static void
7693 {
7694 Entity_Id gnat_field;
7695 tree gnu_list;
7697 /* We operate by first making a list of all fields and their position (we
7698 can get the size easily) and then update all the sizes in the tree. */
7699 gnu_list
7709 {
7711 gnu_list);
7713 {
7714 tree parent_offset;
7716 /* If we are just annotating types and the type is tagged, the tag
7717 and the parent components are not generated by the front-end so
7718 we need to add the appropriate offset to each component without
7719 representation clause. */
7723 {
7724 /* For a component appearing in the current extension, the
7725 offset is the size of the parent. */
7728 parent_offset
7730 bitsizetype);
7731 else
7735 parent_offset
7738 }
7739 else
7742 Set_Component_Bit_Offset
7744 annotate_value
7748 parent_offset)));
7752 }
7754 {
7755 /* If there is no entry, this is an inherited component whose
7756 position is the same as in the parent type. */
7757 Set_Component_Bit_Offset
7763 }
7764 }
7765 }
7766 \f
7767 /* Scan all fields in GNU_TYPE and return a TREE_LIST where TREE_PURPOSE is
7768 the FIELD_DECL and TREE_VALUE a TREE_VEC containing the byte position, the
7769 value to be placed into DECL_OFFSET_ALIGN and the bit position. The list
7770 of fields is flattened, except for variant parts if DO_NOT_FLATTEN_VARIANT
7771 is set to true. GNU_POS is to be added to the position, GNU_BITPOS to the
7772 bit position, OFFSET_ALIGN is the present offset alignment. GNU_LIST is a
7773 pre-existing list to be chained to the newly created entries. */
7775 static tree
7778 {
7779 tree gnu_field;
7782 gnu_field;
7784 {
7789 unsigned int our_offset_align
7798 /* Recurse on internal fields, flattening the nested fields except for
7799 those in the variant part, if requested. */
7801 {
7805 gnu_list
7809 else
7810 gnu_list
7814 }
7815 }
7818 }
7820 /* Return a list describing the substitutions needed to reflect the
7821 discriminant substitutions from GNAT_TYPE to GNAT_SUBTYPE. They can
7822 be in any order. The values in an element of the list are in the form
7823 of operands to SUBSTITUTE_IN_EXPR. DEFINITION is true if this is for
7824 a definition of GNAT_SUBTYPE. */
7828 {
7830 Entity_Id gnat_discrim;
7831 Node_Id gnat_constr;
7838 /* Ignore access discriminants. */
7840 {
7843 elaborate_expression
7849 }
7852 }
7854 /* Scan all fields in QUAL_UNION_TYPE and return a list describing the
7855 variants of QUAL_UNION_TYPE that are still relevant after applying
7856 the substitutions described in SUBST_LIST. GNU_LIST is a pre-existing
7857 list to be prepended to the newly created entries. */
7862 {
7863 tree gnu_field;
7866 gnu_field;
7868 {
7876 /* If the new qualifier is not unconditionally false, its variant may
7877 still be accessed. */
7879 {
7885 /* Recurse on the variant subpart of the variant, if any. */
7891 /* If the new qualifier is unconditionally true, the subsequent
7892 variants cannot be accessed. */
7895 }
7896 }
7899 }
7900 \f
7901 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
7902 corresponding to GNAT_OBJECT. If the size is valid, return an INTEGER_CST
7903 corresponding to its value. Otherwise, return NULL_TREE. KIND is set to
7904 VAR_DECL if we are specifying the size of an object, TYPE_DECL for the
7905 size of a type, and FIELD_DECL for the size of a field. COMPONENT_P is
7906 true if we are being called to process the Component_Size of GNAT_OBJECT;
7907 this is used only for error messages. ZERO_OK is true if a size of zero
7908 is permitted; if ZERO_OK is false, it means that a size of zero should be
7909 treated as an unspecified size. */
7911 static tree
7914 {
7915 Node_Id gnat_error_node;
7918 /* Return 0 if no size was specified. */
7922 /* Ignore a negative size since that corresponds to our back-annotation. */
7926 /* Find the node to use for error messages. */
7933 else
7936 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
7937 but cannot be represented in bitsizetype. */
7940 {
7943 gnat_object);
7944 else
7946 gnat_object);
7948 }
7950 /* Ignore a zero size if it is not permitted. */
7954 /* The size of objects is always a multiple of a byte. */
7957 {
7961 else
7965 }
7967 /* If this is an integral type or a packed array type, the front-end has
7968 already verified the size, so we need not do it here (which would mean
7969 checking against the bounds). However, if this is an aliased object,
7970 it may not be smaller than the type of the object. */
7975 /* If the object is a record that contains a template, add the size of the
7976 template to the specified size. */
7982 /* If a type needs strict alignment, a component of this type in
7983 a packed record cannot be packed and thus uses the type size. */
7986 else
7989 /* Modify the size of a discriminated type to be the maximum size. */
7993 /* If this is an access type or a fat pointer, the minimum size is that given
7994 by the smallest integral mode that's valid for pointers. */
7996 {
8001 }
8003 /* Issue an error either if the default size of the object isn't a constant
8004 or if the new size is smaller than it. */
8008 {
8010 post_error_ne_tree
8013 else
8014 post_error_ne_tree
8018 }
8021 }
8022 \f
8023 /* Similarly, but both validate and process a value of RM size. This routine
8024 is only called for types. */
8026 static void
8028 {
8029 Node_Id gnat_attr_node;
8032 /* Do nothing if no size was specified. */
8036 /* Ignore a negative size since that corresponds to our back-annotation. */
8040 /* Only issue an error if a Value_Size clause was explicitly given.
8041 Otherwise, we'd be duplicating an error on the Size clause. */
8042 gnat_attr_node
8045 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
8046 but cannot be represented in bitsizetype. */
8049 {
8052 gnat_entity);
8054 }
8056 /* Ignore a zero size unless a Value_Size clause exists, or a size clause
8057 exists, or this is an integer type, in which case the front-end will
8058 have always set it. */
8067 /* If the old size is self-referential, get the maximum size. */
8071 /* Issue an error either if the old size of the object isn't a constant or
8072 if the new size is smaller than it. The front-end has already verified
8073 this for scalar and packed array types. */
8081 && TYPE_PACKED_ARRAY_TYPE_P
8084 {
8086 post_error_ne_tree
8090 }
8092 /* Otherwise, set the RM size proper for integral types... */
8099 /* ...or the Ada size for record and union types. */
8103 }
8104 \f
8105 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
8106 a type or object whose present alignment is ALIGN. If this alignment is
8107 valid, return it. Otherwise, give an error and return ALIGN. */
8109 static unsigned int
8111 {
8114 Node_Id gnat_error_node;
8116 /* Don't worry about checking alignment if alignment was not specified
8117 by the source program and we already posted an error for this entity. */
8121 /* Post the error on the alignment clause if any. Note, for the implicit
8122 base type of an array type, the alignment clause is on the first
8123 subtype. */
8131 gnat_error_node =
8134 else
8137 /* Within GCC, an alignment is an integer, so we must make sure a value is
8138 specified that fits in that range. Also, there is an upper bound to
8139 alignments we can support/allow. */
8147 {
8151 /* If the default alignment of "double" or larger scalar types is
8152 specifically capped and the new alignment is above the cap, do
8153 not post an error and change the alignment only if there is an
8154 alignment clause; this makes it possible to have the associated
8155 GCC type overaligned by default for performance reasons. */
8157 {
8158 Entity_Id gnat_type
8160 is_capped_double
8162 }
8164 {
8165 Entity_Id gnat_type
8167 is_capped_double
8169 }
8170 else
8174 {
8177 }
8178 else
8179 {
8186 }
8187 }
8188 else
8189 {
8193 }
8196 }
8197 \f
8198 /* Verify that TYPE is something we can implement atomically. If not, issue
8199 an error for GNAT_ENTITY. COMPONENT_P is true if we are being called to
8200 process a component type. */
8202 static void
8204 {
8206 Node_Id gnat_node;
8207 machine_mode mode;
8210 tree size;
8212 /* If this is an anonymous base type, nothing to check, the error will be
8213 reported on the source type if need be. */
8222 /* Consider all aligned floating-point types atomic and any aligned types
8223 that are represented by integers no wider than a machine word. */
8230 /* For the moment, also allow anything that has an alignment equal to its
8231 size and which is smaller than a word. */
8242 {
8243 unsigned char pragma_id
8248 {
8251 }
8252 }
8257 else
8260 }
8261 \f
8263 /* Helper for the intrin compatibility checks family. Evaluate whether
8264 two types are definitely incompatible. */
8266 static bool
8268 {
8283 {
8290 /* Assume designated types are ok. We'd need to account for char * and
8291 void * variants to do better, which could rapidly get messy and isn't
8292 clearly worth the effort. */
8297 }
8300 }
8302 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8303 on the Ada/builtin argument lists for the INB binding. */
8305 static bool
8307 {
8313 /* Sequence position of the last argument we checked. */
8317 {
8321 /* If we've exhausted both lists simultaneously, we're done. */
8325 /* If one list is shorter than the other, they fail to match. */
8329 /* If we're done with the Ada args and not with the internal builtin
8330 args, or the other way around, complain. */
8333 {
8336 }
8340 {
8344 }
8346 /* Otherwise, check that types match for the current argument. */
8347 argpos ++;
8349 {
8353 }
8358 }
8361 }
8363 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8364 on the Ada/builtin return values for the INB binding. */
8366 static bool
8368 {
8372 /* Accept function imported as procedure, common and convenient. */
8377 /* If return type is Address (integer type), map it to void *. */
8381 /* Check return types compatibility otherwise. Note that this
8382 handles void/void as well. */
8384 {
8388 }
8391 }
8393 /* Check and return whether the Ada and gcc builtin profiles bound by INB are
8394 compatible. Issue relevant warnings when they are not.
8396 This is intended as a light check to diagnose the most obvious cases, not
8397 as a full fledged type compatibility predicate. It is the programmer's
8398 responsibility to ensure correctness of the Ada declarations in Imports,
8399 especially when binding straight to a compiler internal. */
8401 static bool
8403 {
8404 /* Check compatibility on return values and argument lists, each responsible
8405 for posting warnings as appropriate. Ensure use of the proper sloc for
8406 this purpose. */
8419 }
8420 \f
8421 /* Return a FIELD_DECL node modeled on OLD_FIELD. FIELD_TYPE is its type
8422 and RECORD_TYPE is the type of the parent. If SIZE is nonzero, it is the
8423 specified size for this field. POS_LIST is a position list describing
8424 the layout of OLD_FIELD and SUBST_LIST a substitution list to be applied
8425 to this layout. */
8427 static tree
8431 {
8443 /* If the position is now a constant, we can set it as the position of the
8444 field when we make it. Otherwise, we need to deal with it specially. */
8447 else
8450 new_field
8456 {
8458 /* Finalize the position. */
8467 }
8475 }
8477 /* Create the REP part of RECORD_TYPE with REP_TYPE. If MIN_SIZE is nonzero,
8478 it is the minimal size the REP_PART must have. */
8480 static tree
8482 {
8483 tree field;
8493 }
8495 /* Return the REP part of RECORD_TYPE, if any. Otherwise return NULL. */
8497 static tree
8499 {
8502 /* The REP part is the first field, internal, another record, and its name
8503 starts with an 'R'. */
8511 }
8513 /* Return the variant part of RECORD_TYPE, if any. Otherwise return NULL. */
8515 tree
8517 {
8518 tree field;
8520 /* The variant part is the only internal field that is a qualified union. */
8527 }
8529 /* Return a new variant part modeled on OLD_VARIANT_PART. VARIANT_LIST is
8530 the list of variants to be used and RECORD_TYPE is the type of the parent.
8531 POS_LIST is a position list describing the layout of fields present in
8532 OLD_VARIANT_PART and SUBST_LIST a substitution list to be applied to this
8533 layout. */
8535 static tree
8540 {
8548 /* First create the type of the variant part from that of the old one. */
8554 /* If the position of the variant part is constant, subtract it from the
8555 size of the type of the parent to get the new size. This manual CSE
8556 reduces the code size when not optimizing. */
8558 {
8568 first_bit));
8571 }
8572 else
8575 /* Now finish up the new variants and populate the union type. */
8577 {
8581 /* Skip variants that don't belong to this nesting level. */
8585 /* Retrieve the list of fields already added to the new variant. */
8589 /* If the old variant had a variant subpart, we need to create a new
8590 variant subpart and add it to the field list. */
8594 {
8595 tree new_variant_subpart
8600 }
8602 /* Finish up the new variant and create the field. No need for debug
8603 info thanks to the XVS type. */
8607 Empty);
8609 new_field
8617 }
8619 /* Finish up the union type and create the variant part. No need for debug
8620 info thanks to the XVS type. Note that we don't reverse the field list
8621 because VARIANT_LIST has been traversed in reverse order. */
8625 Empty);
8627 new_variant_part
8633 /* With multiple discriminants it is possible for an inner variant to be
8634 statically selected while outer ones are not; in this case, the list
8635 of fields of the inner variant is not flattened and we end up with a
8636 qualified union with a single member. Drop the useless container. */
8638 {
8647 }
8650 }
8652 /* Copy the size (and alignment and alias set) from OLD_TYPE to NEW_TYPE,
8653 which are both RECORD_TYPE, after applying the substitutions described
8654 in SUBST_LIST. */
8656 static void
8659 {
8683 SET_TYPE_ADA_SIZE
8687 /* Finalize the size. */
8690 }
8692 /* Add a parallel type to GNU_TYPE, the translation of GNAT_ENTITY, which is
8693 the implementation type of a packed array type (Is_Packed_Array_Impl_Type).
8694 The parallel type is the original array type if it has been translated. */
8696 static void
8698 {
8699 Entity_Id gnat_original_array_type
8701 tree gnu_original_array_type;
8712 }
8713 \f
8714 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a
8715 type with all size expressions that contain F in a PLACEHOLDER_EXPR
8716 updated by replacing F with R.
8718 The function doesn't update the layout of the type, i.e. it assumes
8719 that the substitution is purely formal. That's why the replacement
8720 value R must itself contain a PLACEHOLDER_EXPR. */
8722 tree
8724 {
8725 tree nt;
8730 {
8736 /* First the domain types of arrays. */
8739 {
8751 SET_TYPE_INDEX_TYPE
8755 }
8757 /* Then the subtypes. */
8760 {
8772 }
8784 /* These should never show up here. */
8788 {
8805 }
8810 {
8812 tree field;
8814 /* Start out with no fields, make new fields, and chain them
8815 in. If we haven't actually changed the type of any field,
8816 discard everything we've done and return the old type. */
8821 {
8826 {
8829 }
8833 {
8836 }
8838 /* Do the substitution inside the qualifier, if any. */
8840 {
8843 {
8846 }
8847 }
8854 }
8864 }
8868 }
8869 }
8870 \f
8871 /* Return the RM size of GNU_TYPE. This is the actual number of bits
8872 needed to represent the object. */
8874 tree
8876 {
8877 /* For integral types, we store the RM size explicitly. */
8881 /* Return the RM size of the actual data plus the size of the template. */
8884 return
8889 /* For record or union types, we store the size explicitly. */
8895 /* For other types, this is just the size. */
8897 }
8898 \f
8899 /* Return the name to be used for GNAT_ENTITY. If a type, create a
8900 fully-qualified name, possibly with type information encoding.
8901 Otherwise, return the name. */
8903 tree
8905 {
8908 }
8910 /* Return an identifier representing the external name to be used for
8911 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
8912 and the specified suffix. */
8914 tree
8916 {
8924 /* A variable using the Stdcall convention lives in a DLL. We adjust
8925 its name to use the jump table, the _imp__NAME contains the address
8926 for the NAME variable. */
8929 {
8935 }
8938 }
8940 /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
8941 string, return a new IDENTIFIER_NODE that is the concatenation of
8942 the name followed by "___" and the specified suffix. */
8944 tree
8946 {
8953 }
8955 /* Initialize data structures of the decl.c module. */
8957 void
8959 {
8960 /* Initialize the cache of annotated values. */
8962 }
8964 /* Destroy data structures of the decl.c module. */
8966 void
8968 {
8969 /* Destroy the cache of annotated values. */
8972 }