| blob | 2eb156b94d09e2edf12266c3f0c22447b5ac0c25 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2018, 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 ****************************************************************************/
55 /* "stdcall" and "thiscall" conventions should be processed in a specific way
56 on 32-bit x86/Windows only. The macros below are helpers to avoid having
57 to check for a Windows specific attribute throughout this unit. */
59 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
60 #ifdef TARGET_64BIT
61 #define Has_Stdcall_Convention(E) \
62 (!TARGET_64BIT && Convention (E) == Convention_Stdcall)
63 #define Has_Thiscall_Convention(E) \
64 (!TARGET_64BIT && is_cplusplus_method (E))
65 #else
66 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
67 #define Has_Thiscall_Convention(E) (is_cplusplus_method (E))
68 #endif
69 #else
70 #define Has_Stdcall_Convention(E) 0
71 #define Has_Thiscall_Convention(E) 0
72 #endif
76 /* Stack realignment is necessary for functions with foreign conventions when
77 the ABI doesn't mandate as much as what the compiler assumes - that is, up
78 to PREFERRED_STACK_BOUNDARY.
80 Such realignment can be requested with a dedicated function type attribute
81 on the targets that support it. We define FOREIGN_FORCE_REALIGN_STACK to
82 characterize the situations where the attribute should be set. We rely on
83 compiler configuration settings for 'main' to decide. */
85 #ifdef MAIN_STACK_BOUNDARY
86 #define FOREIGN_FORCE_REALIGN_STACK \
87 (MAIN_STACK_BOUNDARY < PREFERRED_STACK_BOUNDARY)
88 #else
89 #define FOREIGN_FORCE_REALIGN_STACK 0
90 #endif
92 struct incomplete
93 {
95 tree old_type;
96 Entity_Id full_type;
97 };
99 /* These variables are used to defer recursively expanding incomplete types
100 while we are processing a record, an array or a subprogram type. */
104 /* This variable is used to delay expanding types coming from a limited with
105 clause and completed Taft Amendment types until the end of the spec. */
109 tree discriminant;
110 tree replacement;
115 /* The type of the variant. */
116 tree type;
118 /* The associated field. */
119 tree field;
121 /* The value of the qualifier. */
122 tree qual;
124 /* The type of the variant after transformation. */
125 tree new_type;
127 /* The auxiliary data. */
128 tree aux;
132 /* A map used to cache the result of annotate_value. */
134 {
137 {
139 }
143 {
145 }
147 static int
149 {
151 }
152 };
156 /* A map used to associate a dummy type with a list of subprogram entities. */
158 {
161 };
163 void
165 {
166 }
168 void
170 {
172 }
175 {
178 {
180 }
184 {
186 }
188 static int
190 {
192 }
193 };
226 tree *);
250 /* The relevant constituents of a subprogram binding to a GCC builtin. Used
251 to pass around calls performing profile compatibility checks. */
260 \f
261 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
262 entity, return the equivalent GCC tree for that entity (a ..._DECL node)
263 and associate the ..._DECL node with the input GNAT defining identifier.
265 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
266 initial value (in GCC tree form). This is optional for a variable. For
267 a renamed entity, GNU_EXPR gives the object being renamed.
269 DEFINITION is true if this call is intended for a definition. This is used
270 for separate compilation where it is necessary to know whether an external
271 declaration or a definition must be created if the GCC equivalent was not
272 created previously. */
274 tree
276 {
277 /* Contains the kind of the input GNAT node. */
279 /* True if this is a type. */
281 /* True if this is an artificial entity. */
283 /* True if debug info is requested for this entity. */
285 /* True if this entity is to be considered as imported. */
286 const bool imported_p
288 /* True if this entity has a foreign convention. */
290 /* For a type, contains the equivalent GNAT node to be used in gigi. */
292 /* Temporary used to walk the GNAT tree. */
293 Entity_Id gnat_temp;
294 /* Contains the GCC DECL node which is equivalent to the input GNAT node.
295 This node will be associated with the GNAT node by calling at the end
296 of the `switch' statement. */
298 /* Contains the GCC type to be used for the GCC node. */
300 /* Contains the GCC size tree to be used for the GCC node. */
302 /* Contains the GCC name to be used for the GCC node. */
303 tree gnu_entity_name;
304 /* True if we have already saved gnu_decl as a GNAT association. */
306 /* True if we incremented defer_incomplete_level. */
308 /* True if we incremented force_global. */
310 /* True if we should check to see if elaborated during processing. */
312 /* True if we made GNU_DECL and its type here. */
314 /* Size and alignment of the GCC node, if meaningful. */
316 /* Contains the list of attributes directly attached to the entity. */
319 /* Since a use of an Itype is a definition, process it as such if it is in
320 the main unit, except for E_Access_Subtype because it's actually a use
321 of its base type, and for E_Record_Subtype with cloned subtype because
322 it's actually a use of the cloned subtype, see below. */
324 && is_type
331 {
332 /* Ensure that we are in a subprogram mentioned in the Scope chain of
333 this entity, our current scope is global, or we encountered a task
334 or entry (where we can't currently accurately check scoping). */
337 {
340 }
345 {
350 gnat_temp
362 && (current_function_decl
364 {
367 }
368 }
370 /* This abort means the Itype has an incorrect scope, i.e. that its
371 scope does not correspond to the subprogram it is declared in. */
373 }
375 /* If we've already processed this entity, return what we got last time.
376 If we are defining the node, we should not have already processed it.
377 In that case, we will abort below when we try to save a new GCC tree
378 for this object. We also need to handle the case of getting a dummy
379 type when a Full_View exists but be careful so as not to trigger its
380 premature elaboration. */
383 {
392 {
393 gnu_decl
397 }
400 }
402 /* If this is a numeric or enumeral type, or an access type, a nonzero Esize
403 must be specified unless it was specified by the programmer. Exceptions
404 are for access-to-protected-subprogram types and all access subtypes, as
405 another GNAT type is used to lay out the GCC type for them. */
417 /* The RM size must be specified for all discrete and fixed-point types. */
421 /* If we get here, it means we have not yet done anything with this entity.
422 If we are not defining it, it must be a type or an entity that is defined
423 elsewhere or externally, otherwise we should have defined it already. */
425 || type_annotate_only
426 || is_type
433 /* Get the name of the entity and set up the line number and filename of
434 the original definition for use in any decl we make. Make sure we do not
435 inherit another source location. */
441 /* For cases when we are not defining (i.e., we are referencing from
442 another compilation unit) public entities, show we are at global level
443 for the purpose of computing scopes. Don't do this for components or
444 discriminants since the relevant test is whether or not the record is
445 being defined. */
453 /* Handle any attributes directly attached to the entity. */
457 /* Do some common processing for types. */
459 {
460 /* Compute the equivalent type to be used in gigi. */
463 /* Machine_Attributes on types are expected to be propagated to
464 subtypes. The corresponding Gigi_Rep_Items are only attached
465 to the first subtype though, so we handle the propagation here. */
472 /* Compute a default value for the size of an elementary type. */
474 {
484 else
489 }
490 }
493 {
496 {
497 /* The GNAT record where the component was defined. */
500 /* If the entity is a discriminant of an extended tagged type used to
501 rename a discriminant of the parent type, return the latter. */
505 {
506 gnu_decl
511 }
513 /* If the entity is an inherited component (in the case of extended
514 tagged record types), just return the original entity, which must
515 be a FIELD_DECL. Likewise for discriminants. If the entity is a
516 non-girder discriminant (in the case of derived untagged record
517 types), return the stored discriminant it renames. */
520 {
521 gnu_decl
524 /* GNU_DECL contains a PLACEHOLDER_EXPR for discriminants. */
528 }
530 /* Otherwise, if we are not defining this and we have no GCC type
531 for the containing record, make one for it. Then we should
532 have made our own equivalent. */
534 {
535 /* ??? If this is in a record whose scope is a protected
536 type and we have an Original_Record_Component, use it.
537 This is a workaround for major problems in protected type
538 handling. */
542 {
543 gnu_decl
547 }
548 else
549 {
552 }
556 }
558 /* Here we have no GCC type and this is a reference rather than a
559 definition. This should never happen. Most likely the cause is
560 reference before declaration in the GNAT tree for gnat_entity. */
562 }
565 /* Ignore constant definitions already marked with the error node. See
566 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
570 {
573 }
575 /* Ignore deferred constant definitions without address clause since
576 they are processed fully in the front-end. If No_Initialization
577 is set, this is not a deferred constant but a constant whose value
578 is built manually. And constants that are renamings are handled
579 like variables. */
581 && !gnu_expr
585 {
589 }
591 /* If this is a use of a deferred constant without address clause,
592 get its full definition. */
596 {
597 gnu_decl
601 }
603 /* If we have a constant that we are not defining, get the expression it
604 was defined to represent. This is necessary to avoid generating dumb
605 elaboration code in simple cases, but we may throw it away later if it
606 is not a constant. But do not do it for dispatch tables because they
607 are only referenced indirectly and we need to have a consistent view
608 of the exported and of the imported declarations of the tables from
609 external units for them to be properly merged in LTO mode. Moreover
610 simply do not retrieve the expression it if it is an allocator since
611 the designated type might still be dummy at this point. Note that we
612 invoke gnat_to_gnu_external and not gnat_to_gnu because the expression
613 may contain N_Expression_With_Actions nodes and thus declarations of
614 objects from other units that we need to discard. */
623 /* ... fall through ... */
629 {
631 /* Always create a variable for volatile objects and variables seen
632 constant but with a Linker_Section pragma. */
633 bool const_flag
646 /* We implement RM 13.3(19) for exported and imported (non-constant)
647 objects by making them volatile. */
648 bool volatile_flag
655 tree gnu_object_size;
657 /* We need to translate the renamed object even though we are only
658 referencing the renaming. But it may contain a call for which
659 we'll generate a temporary to hold the return value and which
660 is part of the definition of the renaming, so discard it. */
662 {
666 else
668 }
670 /* Get the type after elaborating the renamed object. */
673 else
674 {
677 /* If this is a standard exception definition, use the standard
678 exception type. This is necessary to make sure that imported
679 and exported views of exceptions are merged in LTO mode. */
683 }
685 /* For a debug renaming declaration, build a debug-only entity. */
687 {
688 /* Force a non-null value to make sure the symbol is retained. */
692 integer_minus_one_node));
700 }
702 /* If this is a loop variable, its type should be the base type.
703 This is because the code for processing a loop determines whether
704 a normal loop end test can be done by comparing the bounds of the
705 loop against those of the base type, which is presumed to be the
706 size used for computation. But this is not correct when the size
707 of the subtype is smaller than the type. */
711 /* Reject non-renamed objects whose type is an unconstrained array or
712 any object whose type is a dummy type or void. */
717 {
720 force_global--;
722 }
724 /* If an alignment is specified, use it if valid. Note that exceptions
725 are objects but don't have an alignment and there is also no point in
726 setting it for an address clause, since the final type of the object
727 will be a reference type. */
734 /* Likewise, if a size is specified, use it if valid. */
736 gnu_size
740 {
741 gnu_type
747 }
749 /* If this object has self-referential size, it must be a record with
750 a default discriminant. We are supposed to allocate an object of
751 the maximum size in this case, unless it is a constant with an
752 initializing expression, in which case we can get the size from
753 that. Note that the resulting size may still be a variable, so
754 this may end up with an indirect allocation. */
757 {
759 {
762 {
763 /* If the initializing expression is itself a constant,
764 despite having a nominal type with self-referential
765 size, we can get the size directly from it. */
767 && TYPE_IS_PADDING_P
771 || DECL_READONLY_ONCE_ELAB
774 else
775 gnu_size
777 }
778 else
780 }
781 /* We may have no GNU_EXPR because No_Initialization is
782 set even though there's an Expression. */
787 gnu_size
789 (Etype
791 else
792 {
795 }
797 /* If the size isn't constant and we are at global level, call
798 elaborate_expression_1 to make a variable for it rather than
799 calculating it each time. */
803 }
805 /* If the size is zero byte, make it one byte since some linkers have
806 troubles with zero-sized objects. If the object will have a
807 template, that will make it nonzero so don't bother. Also avoid
808 doing that for an object renaming or an object with an address
809 clause, as we would lose useful information on the view size
810 (e.g. for null array slices) and we are not allocating the object
811 here anyway. */
823 /* If this is an object with no specified size and alignment, and
824 if either it is atomic or we are not optimizing alignment for
825 space and it is composite and not an exception, an Out parameter
826 or a reference to another object, and the size of its type is a
827 constant, set the alignment to the smallest one which is not
828 smaller than the size, with an appropriate cap. */
837 && !imported_p
843 /* If the object is set to have atomic components, find the component
844 type and validate it.
846 ??? Note that we ignore Has_Volatile_Components on objects; it's
847 not at all clear what to do in that case. */
849 {
858 }
860 /* If this is an aliased object with an unconstrained array nominal
861 subtype, make a type that includes the template. We will either
862 allocate or create a variable of that type, see below. */
866 {
868 gnu_type
870 gnu_type,
873 debug_info_p);
874 }
876 /* ??? If this is an object of CW type initialized to a value, try to
877 ensure that the object is sufficient aligned for this value, but
878 without pessimizing the allocation. This is a kludge necessary
879 because we don't support dynamic alignment. */
886 #ifdef MINIMUM_ATOMIC_ALIGNMENT
887 /* If the size is a constant and no alignment is specified, force
888 the alignment to be the minimum valid atomic alignment. The
889 restriction on constant size avoids problems with variable-size
890 temporaries; if the size is variable, there's no issue with
891 atomic access. Also don't do this for a constant, since it isn't
892 necessary and can interfere with constant replacement. Finally,
893 do not do it for Out parameters since that creates an
894 size inconsistency with In parameters. */
904 #endif
906 /* Make a new type with the desired size and alignment, if needed.
907 But do not take into account alignment promotions to compute the
908 size of the object. */
911 {
917 /* If a padding record was made, declare it now since it will
918 never be declared otherwise. This is necessary to ensure
919 that its subtrees are properly marked. */
923 }
925 /* Now check if the type of the object allows atomic access. */
929 /* If this is a renaming, avoid as much as possible to create a new
930 object. However, in some cases, creating it is required because
931 renaming can be applied to objects that are not names in Ada.
932 This processing needs to be applied to the raw expression so as
933 to make it more likely to rename the underlying object. */
935 {
936 /* If the renamed object had padding, strip off the reference to
937 the inner object and reset our type. */
940 /* Strip useless conversions around the object. */
942 {
945 }
947 /* Or else, if the renamed object has an unconstrained type with
948 default discriminant, use the padded type. */
952 /* Case 1: if this is a constant renaming stemming from a function
953 call, treat it as a normal object whose initial value is what
954 is being renamed. RM 3.3 says that the result of evaluating a
955 function call is a constant object. Therefore, it can be the
956 inner object of a constant renaming and the renaming must be
957 fully instantiated, i.e. it cannot be a reference to (part of)
958 an existing object. And treat other rvalues (addresses, null
959 expressions, constructors and literals) the same way. */
963 /* Expand_Dispatching_Call can prepend a comparison of the tags
964 before the call to "=". */
975 /* We need to detect the case where a temporary is created to
976 hold the return value, since we cannot safely rename it at
977 top level as it lives only in the elaboration routine. */
980 /* We also need to detect the case where the front-end creates
981 a dangling 'reference to a function call at top level and
982 substitutes it in the renaming, for example:
984 q__b : boolean renames r__f.e (1);
986 can be rewritten into:
988 q__R1s : constant q__A2s := r__f'reference;
989 [...]
990 q__b : boolean renames q__R1s.all.e (1);
992 We cannot safely rename the rewritten expression since the
993 underlying object lives only in the elaboration routine. */
995 && (inner
999 ;
1001 /* Case 2: if the renaming entity need not be materialized, use
1002 the elaborated renamed expression for the renaming. But this
1003 means that the caller is responsible for evaluating the address
1004 of the renaming in the correct place for the definition case to
1005 instantiate the SAVE_EXPRs. */
1007 {
1010 gnu_decl
1014 /* We cannot evaluate the first arm of a COMPOUND_EXPR in the
1015 correct place for this case. */
1018 /* No DECL_EXPR will be created so the expression needs to be
1019 marked manually because it will likely be shared. */
1023 /* This assertion will fail if the renamed object isn't aligned
1024 enough as to make it possible to honor the alignment set on
1025 the renaming. */
1027 {
1032 }
1034 /* The expression might not be a DECL so save it manually. */
1039 }
1041 /* Case 3: otherwise, make a constant pointer to the object we
1042 are renaming and attach the object to the pointer after it is
1043 elaborated. The object will be referenced directly instead
1044 of indirectly via the pointer to avoid aliasing problems with
1045 non-addressable entities. The pointer is called a "renaming"
1046 pointer in this case. Note that we also need to preserve the
1047 volatility of the renamed object through the indirection. */
1048 else
1049 {
1053 gnu_type
1062 renamed_obj
1066 /* The expression needs to be marked manually because it will
1067 likely be shared, even for a definition since the ADDR_EXPR
1068 built below can cause the first few nodes to be folded. */
1075 else
1076 {
1077 gnu_expr
1080 gnu_expr
1082 gnu_expr);
1083 }
1084 }
1085 }
1087 /* If we are defining an aliased object whose nominal subtype is
1088 unconstrained, the object is a record that contains both the
1089 template and the object. If there is an initializer, it will
1090 have already been converted to the right type, but we need to
1091 create the template if there is no initializer. */
1093 && !gnu_expr
1096 /* Beware that padding might have been introduced above. */
1099 == RECORD_TYPE
1100 && TYPE_CONTAINS_TEMPLATE_P
1102 {
1103 tree template_field
1111 NULL_TREE);
1114 }
1116 /* Convert the expression to the type of the object if need be. */
1120 /* If this is a pointer that doesn't have an initializing expression,
1121 initialize it to NULL, unless the object is declared imported as
1122 per RM B.1(24). */
1125 && !gnu_expr
1129 /* If we are defining the object and it has an Address clause, we must
1130 either get the address expression from the saved GCC tree for the
1131 object if it has a Freeze node, or elaborate the address expression
1132 here since the front-end has guaranteed that the elaboration has no
1133 effects in this case. */
1135 {
1138 tree gnu_address
1144 /* Convert the type of the object to a reference type that can
1145 alias everything as per RM 13.3(19). */
1148 gnu_type
1152 const_flag
1158 /* If this is an aliased object with an unconstrained array nominal
1159 subtype, then it can overlay only another aliased object with an
1160 unconstrained array nominal subtype and compatible template. */
1164 {
1168 /* This is the pattern built for a regular object. */
1172 /* This is the pattern built for an overaligned object. */
1175 == PLUS_EXPR
1178 gnu_address
1182 else
1183 {
1186 gnat_entity);
1189 }
1190 }
1192 /* If we don't have an initializing expression for the underlying
1193 variable, the initializing expression for the pointer is the
1194 specified address. Otherwise, we have to make a COMPOUND_EXPR
1195 to assign both the address and the initial value. */
1198 else
1199 gnu_expr
1203 NULL_TREE,
1204 gnu_address),
1205 gnu_expr),
1206 gnu_address);
1207 }
1209 /* If it has an address clause and we are not defining it, mark it
1210 as an indirect object. Likewise for Stdcall objects that are
1211 imported. */
1214 {
1215 /* Convert the type of the object to a reference type that can
1216 alias everything as per RM 13.3(19). */
1219 gnu_type
1226 /* No point in taking the address of an initializing expression
1227 that isn't going to be used. */
1230 /* If it has an address clause whose value is known at compile
1231 time, make the object a CONST_DECL. This will avoid a
1232 useless dereference. */
1234 {
1235 Node_Id gnat_address
1239 {
1242 }
1243 }
1244 }
1246 /* If we are at top level and this object is of variable size,
1247 make the actual type a hidden pointer to the real type and
1248 make the initializer be a memory allocation and initialization.
1249 Likewise for objects we aren't defining (presumed to be
1250 external references from other packages), but there we do
1251 not set up an initialization.
1253 If the object's size overflows, make an allocator too, so that
1254 Storage_Error gets raised. Note that we will never free
1255 such memory, so we presume it never will get allocated. */
1258 || !definition
1260 || (gnu_size
1262 size_binop
1264 bitsize_unit_node)),
1266 || !definition
1268 {
1277 /* In case this was a aliased object whose nominal subtype is
1278 unconstrained, the pointer above will be a thin pointer and
1279 build_allocator will automatically make the template.
1281 If we have a template initializer only (that we made above),
1282 pretend there is none and rely on what build_allocator creates
1283 again anyway. Otherwise (if we have a full initializer), get
1284 the data part and feed that to build_allocator.
1286 If we are elaborating a mutable object, tell build_allocator to
1287 ignore a possibly simpler size from the initializer, if any, as
1288 we must allocate the maximum possible size in this case. */
1290 {
1295 {
1296 gnu_alloc_type
1302 else
1303 gnu_expr
1304 = build_component_ref
1308 }
1313 gnat_entity);
1315 gnu_expr
1318 }
1319 else
1321 }
1323 /* If this object would go into the stack and has an alignment larger
1324 than the largest stack alignment the back-end can honor, resort to
1325 a variable of "aligning type". */
1328 && !imported_p
1329 && !static_flag
1331 {
1332 /* Create the new variable. No need for extra room before the
1333 aligned field as this is in automatic storage. */
1334 tree gnu_new_type
1338 tree gnu_new_var
1343 gnat_entity);
1345 /* Initialize the aligned field if we have an initializer. */
1347 add_stmt_with_node
1349 build_component_ref
1352 gnu_expr),
1353 gnat_entity);
1355 /* And setup this entity as a reference to the aligned field. */
1357 gnu_expr
1358 = build_unary_op
1368 }
1370 /* If this is an aggregate constant initialized to a constant, force it
1371 to be statically allocated. This saves an initialization copy. */
1373 && const_flag
1374 && gnu_expr
1383 /* If this is an aliased object with an unconstrained array nominal
1384 subtype, we make its type a thin reference, i.e. the reference
1385 counterpart of a thin pointer, so it points to the array part.
1386 This is aimed to make it easier for the debugger to decode the
1387 object. Note that we have to do it this late because of the
1388 couple of allocation adjustments that might be made above. */
1392 {
1393 /* In case the object with the template has already been allocated
1394 just above, we have nothing to do here. */
1396 {
1397 /* This variable is a GNAT encoding used by Workbench: let it
1398 go through the debugging information but mark it as
1399 artificial: users are not interested in it. */
1400 tree gnu_unc_var
1416 }
1419 gnu_type
1421 }
1423 /* Convert the expression to the type of the object if need be. */
1427 /* If this name is external or a name was specified, use it, but don't
1428 use the Interface_Name with an address clause (see cd30005). */
1434 /* Deal with a pragma Linker_Section on a constant or variable. */
1440 /* Now create the variable or the constant and set various flags. */
1441 gnu_decl
1452 /* If we are defining an Out parameter and optimization isn't enabled,
1453 create a fake PARM_DECL for debugging purposes and make it point to
1454 the VAR_DECL. Suppress debug info for the latter but make sure it
1455 will live in memory so that it can be accessed from within the
1456 debugger through the PARM_DECL. */
1458 && definition
1459 && debug_info_p
1460 && !optimize
1462 {
1469 }
1471 /* If this is a loop parameter, set the corresponding flag. */
1475 /* If this is a renaming pointer, attach the renamed object to it. */
1479 /* If this is a constant and we are defining it or it generates a real
1480 symbol at the object level and we are referencing it, we may want
1481 or need to have a true variable to represent it:
1482 - if optimization isn't enabled, for debugging purposes,
1483 - if the constant is public and not overlaid on something else,
1484 - if its address is taken,
1485 - if either itself or its type is aliased. */
1494 {
1495 tree gnu_corr_var
1503 }
1505 /* If this is a constant, even if we don't need a true variable, we
1506 may need to avoid returning the initializer in every case. That
1507 can happen for the address of a (constant) constructor because,
1508 upon dereferencing it, the constructor will be reinjected in the
1509 tree, which may not be valid in every case; see lvalue_required_p
1510 for more details. */
1514 /* If this object is declared in a block that contains a block with an
1515 exception handler, and we aren't using the GCC exception mechanism,
1516 we must force this variable in memory in order to avoid an invalid
1517 optimization. */
1522 /* If this is a local variable with non-BLKmode and aggregate type,
1523 and optimization isn't enabled, then force it in memory so that
1524 a register won't be allocated to it with possible subparts left
1525 uninitialized and reaching the register allocator. */
1535 /* If we are defining an object with variable size or an object with
1536 fixed size that will be dynamically allocated, and we are using the
1537 front-end setjmp/longjmp exception mechanism, update the setjmp
1538 buffer. */
1551 gnat_entity);
1553 /* Back-annotate Esize and Alignment of the object if not already
1554 known. Note that we pick the values of the type, not those of
1555 the object, to shield ourselves from low-level platform-dependent
1556 adjustments like alignment promotion. This is both consistent with
1557 all the treatment above, where alignment and size are set on the
1558 type of the object and not on the object directly, and makes it
1559 possible to support all confirming representation clauses. */
1561 used_by_ref);
1562 }
1566 /* Return a TYPE_DECL for "void" that we previously made. */
1571 /* A special case: for the types Character and Wide_Character in
1572 Standard, we do not list all the literals. So if the literals
1573 are not specified, make this an integer type. */
1575 {
1578 else
1582 /* Set TYPE_STRING_FLAG for Character and Wide_Character types.
1583 This is needed by the DWARF-2 back-end to distinguish between
1584 unsigned integer types and character types. */
1587 /* This flag is needed by the call just below. */
1591 }
1592 else
1593 {
1594 /* We have a list of enumeral constants in First_Literal. We make a
1595 CONST_DECL for each one and build into GNU_LITERAL_LIST the list
1596 to be placed into TYPE_FIELDS. Each node is itself a TREE_LIST
1597 whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
1598 value of the literal. But when we have a regular boolean type, we
1599 simplify this a little by using a BOOLEAN_TYPE. */
1604 Entity_Id gnat_literal;
1606 /* Boolean types with foreign convention have precision 1. */
1621 {
1622 tree gnu_value
1624 /* Do not generate debug info for individual enumerators. */
1625 tree gnu_literal
1631 gnu_list
1633 }
1638 /* Note that the bounds are updated at the end of this function
1639 to avoid an infinite recursion since they refer to the type. */
1641 }
1645 /* For integer types, just make a signed type the appropriate number
1646 of bits. */
1652 {
1653 /* Small_Value is the scale factor. */
1659 /* Try to decode the scale factor and to save it for the fixed-point
1660 types debug hook. */
1662 /* There are various ways to describe the scale factor, however there
1663 are cases where back-end internals cannot hold it. In such cases,
1664 we output invalid scale factor for such cases (i.e. the 0/0
1665 rational constant) but we expect GNAT to output GNAT encodings,
1666 then. Thus, keep this in sync with
1667 Exp_Dbug.Is_Handled_Scale_Factor. */
1669 /* When encoded as 1/2**N or 1/10**N, describe the scale factor as a
1670 binary or decimal scale: it is easier to read for humans. */
1674 {
1675 /* Given RM restrictions on 'Small values, we assume here that
1676 the denominator fits in an int. */
1679 const tree exponent
1682 scale_factor
1684 integer_one_node,
1687 }
1689 /* Default to arbitrary scale factors descriptions. */
1690 else
1691 {
1696 {
1697 const tree gnu_num
1700 const tree gnu_den
1705 }
1706 else
1707 /* If compiler internals cannot represent arbitrary scale
1708 factors, output an invalid scale factor so that debugger
1709 don't try to handle them but so that we still have a type
1710 in the output. Note that GNAT */
1712 }
1716 }
1720 {
1721 /* For modular types, make the unsigned type of the proper number
1722 of bits and then set up the modulus, if required. */
1725 /* Packed Array Impl. Types are supposed to be subtypes only. */
1730 /* Get the modulus in this type. If it overflows, assume it is because
1731 it is equal to 2**Esize. Note that there is no overflow checking
1732 done on unsigned type, so we detect the overflow by looking for
1733 a modulus of zero, which is otherwise invalid. */
1737 {
1742 }
1744 /* If the upper bound is not maximal, make an extra subtype. */
1747 {
1754 }
1755 }
1764 /* For integral subtypes, we make a new INTEGER_TYPE. Note that we do
1765 not want to call create_range_type since we would like each subtype
1766 node to be distinct. ??? Historically this was in preparation for
1767 when memory aliasing is implemented, but that's obsolete now given
1768 the call to relate_alias_sets below.
1770 The TREE_TYPE field of the INTEGER_TYPE points to the base type;
1771 this fact is used by the arithmetic conversion functions.
1773 We elaborate the Ancestor_Subtype if it is not in the current unit
1774 and one of our bounds is non-static. We do this to ensure consistent
1775 naming in the case where several subtypes share the same bounds, by
1776 elaborating the first such subtype first, thus using its name. */
1785 /* Set the precision to the Esize except for bit-packed arrays. */
1790 /* Boolean types with foreign convention have precision 1. */
1792 {
1798 }
1799 /* First subtypes of Character are treated as Character; otherwise
1800 this should be an unsigned type if the base type is unsigned or
1801 if the lower bound is constant and non-negative or if the type
1802 is biased. However, even if the lower bound is constant and
1803 non-negative, we use a signed type for a subtype with the same
1804 size as its signed base type, because this eliminates useless
1805 conversions to it and gives more leeway to the optimizer; but
1806 this means that we will need to explicitly test for this case
1807 when we change the representation based on the RM size. */
1819 else
1823 SET_TYPE_RM_MIN_VALUE
1826 debug_info_p));
1828 SET_TYPE_RM_MAX_VALUE
1831 debug_info_p));
1837 /* Do the same processing for Character subtypes as for types. */
1839 {
1844 }
1846 /* Inherit our alias set from what we're a subtype of. Subtypes
1847 are not different types and a pointer can designate any instance
1848 within a subtype hierarchy. */
1851 /* One of the above calls might have caused us to be elaborated,
1852 so don't blow up if so. */
1854 {
1857 }
1859 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
1863 /* For a packed array, make the original array type a parallel/debug
1864 type. */
1868 discrete_type:
1870 /* We have to handle clauses that under-align the type specially. */
1873 && Present
1876 {
1880 }
1882 /* If the type we are dealing with represents a bit-packed array,
1883 we need to have the bits left justified on big-endian targets
1884 and right justified on little-endian targets. We also need to
1885 ensure that when the value is read (e.g. for comparison of two
1886 such values), we only get the good bits, since the unused bits
1887 are uninitialized. Both goals are accomplished by wrapping up
1888 the modular type in an enclosing record type. */
1891 {
1894 /* Set the RM size before wrapping up the original type. */
1899 /* Create a stripped-down declaration, mainly for debugging. */
1901 gnat_entity);
1903 /* Now save it and build the enclosing record type. */
1913 /* Propagate the alignment of the modular type to the record type,
1914 unless there is an alignment clause that under-aligns the type.
1915 This means that bit-packed arrays are given "ceil" alignment for
1916 their size by default, which may seem counter-intuitive but makes
1917 it possible to overlay them on modular types easily. */
1921 /* Propagate the reverse storage order flag to the record type so
1922 that the required byte swapping is performed when retrieving the
1923 enclosed modular value. */
1929 /* Don't declare the field as addressable since we won't be taking
1930 its address and this would prevent create_field_decl from making
1931 a bitfield. */
1932 gnu_field
1936 /* We will output additional debug info manually below. */
1941 {
1942 /* Make the original array type a parallel/debug type. */
1945 /* Since GNU_TYPE is a padding type around the packed array
1946 implementation type, the padded type is its debug type. */
1949 }
1950 }
1952 /* If the type we are dealing with has got a smaller alignment than the
1953 natural one, we need to wrap it up in a record type and misalign the
1954 latter; we reuse the padding machinery for this purpose. */
1956 {
1959 /* Set the RM size before wrapping the type. */
1962 gnu_type
1968 }
1973 /* The type of the Low and High bounds can be our type if this is
1974 a type from Standard, so set them at the end of the function. */
1981 /* See the E_Signed_Integer_Subtype case for the rationale. */
1998 SET_TYPE_RM_MIN_VALUE
2001 debug_info_p));
2003 SET_TYPE_RM_MAX_VALUE
2006 debug_info_p));
2008 /* Inherit our alias set from what we're a subtype of, as for
2009 integer subtypes. */
2012 /* One of the above calls might have caused us to be elaborated,
2013 so don't blow up if so. */
2017 /* Array Types and Subtypes
2019 Unconstrained array types are represented by E_Array_Type and
2020 constrained array types are represented by E_Array_Subtype. There
2021 are no actual objects of an unconstrained array type; all we have
2022 are pointers to that type.
2024 The following fields are defined on array types and subtypes:
2026 Component_Type Component type of the array.
2027 Number_Dimensions Number of dimensions (an int).
2028 First_Index Type of first index. */
2031 {
2032 const bool convention_fortran_p
2035 tree gnu_template_type;
2036 tree gnu_ptr_template;
2043 tree comp_type;
2045 /* Create the type for the component now, as it simplifies breaking
2046 type reference loops. */
2047 comp_type
2050 {
2051 /* As a side effect, the type may have been translated. */
2054 }
2056 /* We complete an existing dummy fat pointer type in place. This both
2057 avoids further complex adjustments in update_pointer_to and yields
2058 better debugging information in DWARF by leveraging the support for
2059 incomplete declarations of "tagged" types in the DWARF back-end. */
2062 {
2065 gnu_ptr_template =
2069 /* Save the contents of the dummy type for update_pointer_to. */
2075 }
2076 else
2077 {
2081 }
2083 /* Make a node for the array. If we are not defining the array
2084 suppress expanding incomplete types. */
2088 {
2089 defer_incomplete_level++;
2091 }
2093 /* Build the fat pointer type. Use a "void *" object instead of
2094 a pointer to the array type since we don't have the array type
2095 yet (it will reference the fat pointer via the bounds). Note
2096 that we reuse the existing fields of a dummy type because for:
2098 type Arr is array (Positive range <>) of Element_Type;
2099 type Array_Ref is access Arr;
2100 Var : Array_Ref := Null;
2102 in a declarative part, Arr will be frozen only after Var, which
2103 means that the fields used in the CONSTRUCTOR built for Null are
2104 those of the dummy type, which in turn means that COMPONENT_REFs
2105 of Var may be built with these fields. Now if COMPONENT_REFs of
2106 Var are also built later with the fields of the final type, the
2107 aliasing machinery may consider that the accesses are distinct
2108 if the FIELD_DECLs are distinct as objects. */
2110 {
2117 }
2118 else
2119 {
2120 tem
2130 }
2132 /* Build a reference to the template from a PLACEHOLDER_EXPR that
2133 is the fat pointer. This will be used to access the individual
2134 fields once we build them. */
2138 gnu_template_reference
2143 /* Now create the GCC type for each index and add the fields for that
2144 index to the template. */
2150 {
2153 tree gnu_index_base_type
2158 /* Make the FIELD_DECLs for the low and high bounds of this
2159 type and then make extractions of these fields from the
2160 template. */
2163 gnu_index_base_type,
2171 gnu_index_base_type,
2179 /* We can't use build_component_ref here since the template type
2180 isn't complete yet. */
2183 NULL_TREE);
2186 NULL_TREE);
2192 /* Compute the size of this dimension. See the E_Array_Subtype
2193 case below for the rationale. */
2194 gnu_high
2198 gnu_max,
2201 /* Make a range type with the new range in the Ada base type.
2202 Then make an index type with the size range in sizetype. */
2206 gnu_orig_min,
2207 gnu_orig_max),
2208 gnat_entity);
2210 /* Update the maximum size of the array in elements. */
2212 {
2213 tree gnu_min
2215 tree gnu_max
2217 tree gnu_this_max
2224 else
2225 gnu_max_size
2227 }
2231 }
2233 /* Install all the fields into the template. */
2238 gnu_template_fields
2241 debug_info_p);
2244 /* If Component_Size is not already specified, annotate it with the
2245 size of the component. */
2250 /* Compute the maximum size of the array in units and bits. */
2252 {
2258 }
2259 else
2262 /* Now build the array type. */
2265 {
2273 }
2275 /* If an alignment is specified, use it if valid. But ignore it
2276 for the original type of packed array types. If the alignment
2277 was requested with an explicit alignment clause, state so. */
2280 {
2283 gnat_entity,
2287 }
2289 /* Tag top-level ARRAY_TYPE nodes for packed arrays and their
2290 implementation types as such so that the debug information back-end
2291 can output the appropriate description for them. */
2299 /* Adjust the type of the pointer-to-array field of the fat pointer
2300 and record the aliasing relationships if necessary. */
2305 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2306 corresponding fat pointer. */
2313 /* If the maximum size doesn't overflow, use it. */
2319 {
2324 }
2329 /* If told to generate GNAT encodings for them (GDB rely on them at the
2330 moment): give the fat pointer type a name. If this is a packed
2331 array, tell the debugger how to interpret the underlying bits. */
2334 else
2336 tree xup_name
2341 gnat_entity);
2343 /* Create the type to be designated by thin pointers: a record type for
2344 the array and its template. We used to shift the fields to have the
2345 template at a negative offset, but this was somewhat of a kludge; we
2346 now shift thin pointer values explicitly but only those which have a
2347 TYPE_UNCONSTRAINED_ARRAY attached to the designated RECORD_TYPE.
2348 Note that GDB can handle standard DWARF information for them, so we
2349 don't have to name them as a GNAT encoding, except if specifically
2350 asked to. */
2351 tree xut_name
2356 debug_info_p);
2360 }
2365 /* This is the actual data type for array variables. Multidimensional
2366 arrays are implemented as arrays of arrays. Note that arrays which
2367 have sparse enumeration subtypes as index components create sparse
2368 arrays, which is obviously space inefficient but so much easier to
2369 code for now.
2371 Also note that the subtype never refers to the unconstrained array
2372 type, which is somewhat at variance with Ada semantics.
2374 First check to see if this is simply a renaming of the array type.
2375 If so, the result is the array type. */
2379 ;
2380 else
2381 {
2383 const bool convention_fortran_p
2392 /* First create the GCC type for each index and find out whether
2393 special types are needed for debugging information. */
2396 gnat_base_index
2402 {
2404 tree gnu_index_base_type
2406 tree gnu_orig_min
2409 tree gnu_orig_max
2414 tree gnu_base_index_type
2416 tree gnu_base_index_base_type
2418 tree gnu_base_orig_min
2421 tree gnu_base_orig_max
2424 tree gnu_high;
2426 /* See if the base array type is already flat. If it is, we
2427 are probably compiling an ACATS test but it will cause the
2428 code below to malfunction if we don't handle it specially. */
2432 {
2436 }
2438 /* Similarly, if one of the values overflows in sizetype and the
2439 range is null, use 1..0 for the sizetype bounds. */
2444 {
2448 }
2450 /* If the minimum and maximum values both overflow in sizetype,
2451 but the difference in the original type does not overflow in
2452 sizetype, ignore the overflow indication. */
2456 && !TREE_OVERFLOW
2459 gnu_orig_max,
2460 gnu_orig_min))))
2461 {
2465 }
2467 /* Compute the size of this dimension in the general case. We
2468 need to provide GCC with an upper bound to use but have to
2469 deal with the "superflat" case. There are three ways to do
2470 this. If we can prove that the array can never be superflat,
2471 we can just use the high bound of the index type. */
2474 /* Bit-Packed Array Impl. Types are never superflat. */
2476 && Is_Bit_Packed_Array
2480 /* Otherwise, if the high bound is constant but the low bound is
2481 not, we use the expression (hb >= lb) ? lb : hb + 1 for the
2482 lower bound. Note that the comparison must be done in the
2483 original type to avoid any overflow during the conversion. */
2486 {
2488 gnu_min
2491 boolean_type_node,
2492 gnu_orig_max,
2493 gnu_orig_min),
2494 gnu_min,
2496 size_one_node));
2497 }
2499 /* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
2500 in all the other cases. Note that, here as well as above,
2501 the condition used in the comparison must be equivalent to
2502 the condition (length != 0). This is relied upon in order
2503 to optimize array comparisons in compare_arrays. Moreover
2504 we use int_const_binop for the shift by 1 if the bound is
2505 constant to avoid any unwanted overflow. */
2506 else
2507 gnu_high
2510 boolean_type_node,
2511 gnu_orig_max,
2512 gnu_orig_min),
2513 gnu_max,
2516 size_one_node)
2518 size_one_node));
2520 /* Reuse the index type for the range type. Then make an index
2521 type with the size range in sizetype. */
2524 gnat_entity);
2526 /* Update the maximum size of the array in elements. Here we
2527 see if any constraint on the index type of the base type
2528 can be used in the case of self-referential bound on the
2529 index type of the subtype. We look for a non-"infinite"
2530 and non-self-referential bound from any type involved and
2531 handle each bound separately. */
2533 {
2536 tree gnu_base_base_min
2539 tree gnu_base_base_max
2560 else
2561 {
2562 tree gnu_this_max;
2564 /* Use int_const_binop if the bounds are constant to
2565 avoid any unwanted overflow. */
2568 gnu_this_max
2571 gnu_base_max,
2572 gnu_base_min));
2573 else
2574 gnu_this_max
2577 gnu_base_max,
2578 gnu_base_min));
2580 gnu_max_size
2582 }
2583 }
2585 /* We need special types for debugging information to point to
2586 the index types if they have variable bounds, are not integer
2587 types, are biased or are wider than sizetype. These are GNAT
2588 encodings, so we have to include them only when all encodings
2589 are requested. */
2599 }
2601 /* Then flatten: create the array of arrays. For an array type
2602 used to implement a packed array, get the component type from
2603 the original array type since the representation clauses that
2604 can affect it are on the latter. */
2607 {
2612 /* One of the above calls might have caused us to be elaborated,
2613 so don't blow up if so. */
2615 {
2618 }
2619 }
2620 else
2621 {
2623 debug_info_p);
2625 /* One of the above calls might have caused us to be elaborated,
2626 so don't blow up if so. */
2628 {
2631 }
2632 }
2634 /* Compute the maximum size of the array in units and bits. */
2636 {
2642 }
2643 else
2646 /* Now build the array type. */
2648 {
2657 }
2659 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
2663 /* If this is a multi-dimensional array and we are at global level,
2664 we need to make a variable corresponding to the stride of the
2665 inner dimensions. */
2667 {
2668 tree gnu_arr_type;
2673 {
2683 /* ??? For now, store the size as a multiple of the
2684 alignment of the element type in bytes so that we
2685 can see the alignment from the tree. */
2693 /* ??? create_type_decl is not invoked on the inner types so
2694 the MULT_EXPR node built above will never be marked. */
2696 }
2697 }
2699 /* If we need to write out a record type giving the names of the
2700 bounds for debugging purposes, do it now and make the record
2701 type a parallel type. This is not needed for a packed array
2702 since the bounds are conveyed by the original array type. */
2704 && debug_info_p
2706 {
2709 tree gnu_field;
2715 {
2719 /* Make sure to reference the types themselves, and not just
2720 their names, as the debugger may fall back on them. */
2726 }
2730 }
2732 /* If this is a packed array type, make the original array type a
2733 parallel/debug type. Otherwise, if such GNAT encodings are
2734 required, do it for the base array type if it isn't artificial to
2735 make sure it is kept in the debug info. */
2737 {
2740 gnat_entity);
2741 else
2742 {
2743 tree gnu_base_decl
2750 }
2751 }
2757 /* Tag top-level ARRAY_TYPE nodes for packed arrays and their
2758 implementation types as such so that the debug information back-end
2759 can output the appropriate description for them. */
2764 /* If the size is self-referential and the maximum size doesn't
2765 overflow, use it. */
2767 && gnu_max_size
2772 {
2778 }
2780 /* Set our alias set to that of our base type. This gives all
2781 array subtypes the same alias set. */
2784 /* If this is a packed type implemented specially, then replace our
2785 type with the implementation type. */
2787 {
2788 /* First finish the type we had been making so that we output
2789 debugging information for it. */
2792 {
2793 const int quals
2794 = TYPE_QUAL_VOLATILE
2797 }
2798 /* Make it artificial only if the base type was artificial too.
2799 That's sort of "morally" true and will make it possible for
2800 the debugger to look it up by name in DWARF, which is needed
2801 in order to decode the packed array type. */
2802 tree gnu_tmp_decl
2806 gnat_entity);
2807 /* Save it as our equivalent in case the call below elaborates
2808 this type again. */
2811 gnu_type
2815 /* Set the ___XP suffix for GNAT encodings. */
2825 /* We need to attach the index type to the type we just made so
2826 that the actual bounds can later be put into a template. */
2831 {
2833 {
2834 /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
2835 TYPE_MODULUS for modular types so we make an extra
2836 subtype if necessary. */
2838 {
2839 tree gnu_subtype
2848 }
2852 /* Check for other cases of overloading. */
2854 }
2859 SET_TYPE_ACTUAL_BOUNDS
2866 SET_TYPE_ACTUAL_BOUNDS
2872 }
2873 }
2874 }
2878 /* Create the type for a string literal. */
2879 {
2880 Entity_Id gnat_full_type
2885 tree gnu_string_array_type
2887 tree gnu_string_index_type
2890 tree gnu_lower_bound
2893 tree gnu_length
2895 gnu_string_index_type);
2896 tree gnu_upper_bound
2898 gnu_lower_bound,
2901 integer_one_node)));
2902 tree gnu_index_type
2906 gnu_lower_bound,
2907 gnu_upper_bound),
2908 gnat_entity);
2910 gnu_type
2913 gnu_index_type);
2917 }
2920 /* Record Types and Subtypes
2922 The following fields are defined on record types:
2924 Has_Discriminants True if the record has discriminants
2925 First_Discriminant Points to head of list of discriminants
2926 First_Entity Points to head of list of fields
2927 Is_Tagged_Type True if the record is tagged
2929 Implementation of Ada records and discriminated records:
2931 A record type definition is transformed into the equivalent of a C
2932 struct definition. The fields that are the discriminants which are
2933 found in the Full_Type_Declaration node and the elements of the
2934 Component_List found in the Record_Type_Definition node. The
2935 Component_List can be a recursive structure since each Variant of
2936 the Variant_Part of the Component_List has a Component_List.
2938 Processing of a record type definition comprises starting the list of
2939 field declarations here from the discriminants and the calling the
2940 function components_to_record to add the rest of the fields from the
2941 component list and return the gnu type node. The function
2942 components_to_record will call itself recursively as it traverses
2943 the tree. */
2947 {
2948 gnu_type
2949 = build_complex_type
2950 (get_unpadded_type
2953 (Component_List
2954 (Type_Definition
2958 }
2960 {
2963 Node_Id gnat_constr;
2966 tree gnu_get_parent;
2967 /* Set PACKED in keeping with gnat_to_gnu_field. */
2968 const int packed
2977 const bool is_extension
2983 /* See if all fields have a rep clause. Stop when we find one
2984 that doesn't. */
2992 {
2995 }
2997 /* If this is a record extension, go a level further to find the
2998 record definition. Also, verify we have a Parent_Subtype. */
3000 {
3007 }
3009 /* Make a node for the record. If we are not defining the record,
3010 suppress expanding incomplete types. */
3019 {
3020 defer_incomplete_level++;
3022 }
3024 /* If both a size and rep clause were specified, put the size on
3025 the record type now so that it can get the proper layout. */
3030 /* Always set the alignment on the record type here so that it can
3031 get the proper layout. */
3036 else
3037 {
3040 /* If a type needs strict alignment, the minimum size will be the
3041 type size instead of the RM size (see validate_size). Cap the
3042 alignment lest it causes this type size to become too large. */
3044 {
3049 }
3050 }
3052 /* If we have a Parent_Subtype, make a field for the parent. If
3053 this record has rep clauses, force the position to zero. */
3055 {
3058 tree gnu_parent;
3061 /* A major complexity here is that the parent subtype will
3062 reference our discriminants in its Stored_Constraint list.
3063 But those must reference the parent component of this record
3064 which is precisely of the parent subtype we have not built yet!
3065 To break the circle we first build a dummy COMPONENT_REF which
3066 represents the "get to the parent" operation and initialize
3067 each of those discriminants to a COMPONENT_REF of the above
3068 dummy parent referencing the corresponding discriminant of the
3069 base type of the parent subtype. */
3074 gnu_dummy_parent_type),
3075 NULL_TREE);
3082 {
3083 tree gnu_field
3086 save_gnu_tree
3091 }
3093 /* Then we build the parent subtype. If it has discriminants but
3094 the type itself has unknown discriminants, this means that it
3095 doesn't contain information about how the discriminants are
3096 derived from those of the ancestor type, so it cannot be used
3097 directly. Instead it is built by cloning the parent subtype
3098 of the underlying record view of the type, for which the above
3099 derivation of discriminants has been made explicit. */
3102 {
3105 /* If we are defining the type, the underlying record
3106 view must already have been elaborated at this point.
3107 Otherwise do it now as its parent subtype cannot be
3108 technically elaborated on its own. */
3111 else
3116 /* Substitute the "get to the parent" of the type for that
3117 of its underlying record view in the cloned type. */
3122 {
3124 tree gnu_ref
3127 gnu_parent
3129 }
3130 }
3131 else
3134 /* The parent field needs strict alignment so, if it is to
3135 be created with a component clause below, then we need
3136 to apply the same adjustment as in gnat_to_gnu_field. */
3138 {
3139 /* ??? For historical reasons, we do it on strict-alignment
3140 platforms only, where it is really required. This means
3141 that a confirming representation clause will change the
3142 behavior of the compiler on the other platforms. */
3145 else
3146 parent_packed
3148 }
3150 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
3151 initially built. The discriminants must reference the fields
3152 of the parent subtype and not those of its base type for the
3153 placeholder machinery to properly work. */
3155 {
3156 /* The actual parent subtype is the full view. */
3158 {
3161 else
3163 }
3169 {
3170 Entity_Id field;
3179 }
3180 }
3182 /* The "get to the parent" COMPONENT_REF must be given its
3183 proper type... */
3186 /* ...and reference the _Parent field of this record. */
3187 gnu_field
3190 has_rep
3192 has_rep
3198 }
3200 /* Make the fields for the discriminants and put them into the record
3201 unless it's an Unchecked_Union. */
3206 {
3207 /* If this is a record extension and this discriminant is the
3208 renaming of another discriminant, we've handled it above. */
3213 gnu_field
3215 debug_info_p);
3217 /* Make an expression using a PLACEHOLDER_EXPR from the
3218 FIELD_DECL node just created and link that with the
3219 corresponding GNAT defining identifier. */
3227 {
3230 }
3231 }
3233 /* If we have a derived untagged type that renames discriminants in
3234 the parent type, the (stored) discriminants are just a copy of the
3235 discriminants of the parent type. This means that any constraints
3236 added by the renaming in the derivation are disregarded as far as
3237 the layout of the derived type is concerned. To rescue them, we
3238 change the type of the (stored) discriminants to a subtype with
3239 the bounds of the type of the visible discriminants. */
3241 && !is_extension
3247 /* Ignore access discriminants. */
3250 {
3253 tree gnu_ref
3257 /* GNU_REF must be an expression using a PLACEHOLDER_EXPR built
3258 just above for one of the stored discriminants. */
3262 {
3264 tree gnu_subtype
3275 }
3276 }
3278 /* If this is a derived type with discriminants and these discriminants
3279 affect the initial shape it has inherited, factor them in. */
3281 && !is_extension
3289 {
3290 tree gnu_parent_type
3299 /* Set the layout of the type to match that of the parent type,
3300 doing required substitutions. If we are in minimal GNAT
3301 encodings mode, we don't need debug info for the inner record
3302 types, as they will be part of the embedding variant record's
3303 debug info. */
3304 copy_and_substitute_in_layout
3306 gnu_subst_list,
3308 }
3309 else
3310 {
3311 /* Add the fields into the record type and finish it up. */
3318 NULL);
3320 /* Empty classes have the size of a storage unit in C++. */
3323 {
3327 }
3329 /* If there are entities in the chain corresponding to components
3330 that we did not elaborate, ensure we elaborate their types if
3331 they are Itypes. */
3340 }
3342 /* Fill in locations of fields. */
3345 /* If this is a record type associated with an exception definition,
3346 equate its fields to those of the standard exception type. This
3347 will make it possible to convert between them. */
3349 {
3350 tree gnu_std_field;
3353 gnu_field;
3358 }
3359 }
3363 /* If an equivalent type is present, that is what we should use.
3364 Otherwise, fall through to handle this like a record subtype
3365 since it may have constraints. */
3367 {
3371 }
3373 /* ... fall through ... */
3376 /* If Cloned_Subtype is Present it means this record subtype has
3377 identical layout to that type or subtype and we should use
3378 that GCC type for this one. The front end guarantees that
3379 the component list is shared. */
3381 {
3386 }
3388 /* Otherwise, first ensure the base type is elaborated. Then, if we are
3389 changing the type, make a new type with each field having the type of
3390 the field in the new subtype but the position computed by transforming
3391 every discriminant reference according to the constraints. We don't
3392 see any difference between private and non-private type here since
3393 derivations from types should have been deferred until the completion
3394 of the private type. */
3395 else
3396 {
3400 {
3401 defer_incomplete_level++;
3403 }
3405 tree gnu_base_type
3409 {
3412 }
3414 /* When the subtype has discriminants and these discriminants affect
3415 the initial shape it has inherited, factor them in. But for an
3416 Unchecked_Union (it must be an Itype), just return the type. */
3422 {
3425 tree gnu_unpad_base_type;
3430 {
3431 /* Use the ultimate base record type as the debug type.
3432 Subtypes and derived types bring no useful
3433 information. */
3437 tree gnu_debug_type
3440 }
3446 /* Set the size, alignment and alias set of the type to match
3447 those of the base type, doing required substitutions. */
3449 gnu_subst_list);
3453 else
3456 /* Set the layout of the type to match that of the base type,
3457 doing required substitutions. We will output debug info
3458 manually below so pass false as last argument. */
3463 /* Fill in locations of fields. */
3466 /* If debugging information is being written for the type and if
3467 we are asked to output such encodings, write a record that
3468 shows what we are a subtype of and also make a variable that
3469 indicates our size, if still variable. */
3471 {
3473 tree gnu_unpad_base_name
3481 build_reference_type
3483 gnu_subtype_marker,
3500 }
3501 }
3503 /* Otherwise, go down all the components in the new type and make
3504 them equivalent to those in the base type. */
3505 else
3506 {
3516 gnat_to_gnu_field_decl
3519 }
3520 }
3525 /* Use the special descriptor type for dispatch tables if needed,
3526 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3527 Note that we are only required to do so for static tables in
3528 order to be compatible with the C++ ABI, but Ada 2005 allows
3529 to extend library level tagged types at the local level so
3530 we do it in the non-static case as well. */
3533 {
3537 }
3539 /* ... fall through ... */
3546 {
3547 /* The designated type and its equivalent type for gigi. */
3550 /* Whether it comes from a limited with. */
3551 const bool is_from_limited_with
3554 /* Whether it is a completed Taft Amendment type. Such a type is to
3555 be treated as coming from a limited with clause if it is not in
3556 the main unit, i.e. we break potential circularities here in case
3557 the body of an external unit is loaded for inter-unit inlining. */
3558 const bool is_completed_taft_type
3562 /* The "full view" of the designated type. If this is an incomplete
3563 entity from a limited with, treat its non-limited view as the full
3564 view. Otherwise, if this is an incomplete or private type, use the
3565 full view. In the former case, we might point to a private type,
3566 in which case, we need its full view. Also, we want to look at the
3567 actual type used for the representation, so this takes a total of
3568 three steps. */
3569 Entity_Id gnat_desig_full_direct_first
3570 = (is_from_limited_with
3574 Entity_Id gnat_desig_full_direct
3575 = ((is_from_limited_with
3580 Entity_Id gnat_desig_full
3582 /* The type actually used to represent the designated type, either
3583 gnat_desig_full or gnat_desig_equiv. */
3584 Entity_Id gnat_desig_rep;
3585 /* We want to know if we'll be seeing the freeze node for any
3586 incomplete type we may be pointing to. */
3587 const bool in_main_unit
3591 /* True if we make a dummy type here. */
3593 /* The mode to be used for the pointer type. */
3594 scalar_int_mode p_mode;
3595 /* The GCC type used for the designated type. */
3602 /* If either the designated type or its full view is an unconstrained
3603 array subtype, replace it with the type it's a subtype of. This
3604 avoids problems with multiple copies of unconstrained array types.
3605 Likewise, if the designated type is a subtype of an incomplete
3606 record type, use the parent type to avoid order of elaboration
3607 issues. This can lose some code efficiency, but there is no
3608 alternative. */
3619 /* Set the type that's the representation of the designated type. */
3620 gnat_desig_rep
3623 /* If we already know what the full type is, use it. */
3627 /* Get the type of the thing we are to point to and build a pointer to
3628 it. If it is a reference to an incomplete or private type with a
3629 full view that is a record, an array or an access, make a dummy type
3630 and get the actual type later when we have verified it is safe. */
3637 /* Likewise if this is a reference to a record, an array or a
3638 subprogram type and we are to defer elaborating incomplete
3639 types. We do this because this access type may be the full
3640 view of a private type. */
3647 /* If this is a reference from a limited_with type back to our
3648 main unit and there's a freeze node for it, either we have
3649 already processed the declaration and made the dummy type,
3650 in which case we just reuse the latter, or we have not yet,
3651 in which case we make the dummy type and it will be reused
3652 when the declaration is finally processed. In both cases,
3653 the pointer eventually created below will be automatically
3654 adjusted when the freeze node is processed. */
3655 || (in_main_unit
3656 && is_from_limited_with
3658 {
3661 }
3663 /* Otherwise handle the case of a pointer to itself. */
3665 {
3666 gnu_type
3670 }
3672 /* If expansion is disabled, the equivalent type of a concurrent type
3673 is absent, so we use the void pointer type. */
3677 /* If the ultimately designated type is an incomplete type with no full
3678 view, we use the void pointer type in LTO mode to avoid emitting a
3679 dummy type in the GIMPLE IR. We cannot do that in regular mode as
3680 the name of the dummy type in used by GDB for a global lookup. */
3686 /* Finally, handle the default case where we can just elaborate our
3687 designated type. */
3688 else
3691 /* It is possible that a call to gnat_to_gnu_type above resolved our
3692 type. If so, just return it. */
3694 {
3697 }
3699 /* Access-to-unconstrained-array types need a special treatment. */
3701 {
3702 /* If the processing above got something that has a pointer, then
3703 we are done. This could have happened either because the type
3704 was elaborated or because somebody else executed the code. */
3709 }
3711 /* If we haven't done it yet, build the pointer type the usual way. */
3713 {
3714 /* Modify the designated type if we are pointing only to constant
3715 objects, but don't do it for a dummy type. */
3718 gnu_desig_type
3721 gnu_type
3724 }
3726 /* If the designated type is not declared in the main unit and we made
3727 a dummy node for it, save our definition, elaborate the actual type
3728 and replace the dummy type we made with the actual one. But if we
3729 are to defer actually looking up the actual type, make an entry in
3730 the deferred list instead. If this is from a limited with, we may
3731 have to defer until the end of the current unit. */
3733 {
3735 gnu_type
3741 gnat_entity);
3748 && !is_from_limited_with
3750 {
3753 }
3754 else
3755 {
3765 }
3766 }
3767 }
3772 /* If we are just annotating types and have no equivalent record type,
3773 just use the void pointer type. */
3777 /* The run-time representation is the equivalent type. */
3778 else
3779 {
3782 }
3784 /* The designated subtype must be elaborated as well, if it does
3785 not have its own freeze node. */
3796 /* We treat this as identical to its base type; any constraint is
3797 meaningful only to the front-end. */
3801 /* The designated subtype must be elaborated as well, if it does
3802 not have its own freeze node. But designated subtypes created
3803 for constrained components of records with discriminants are
3804 not frozen by the front-end and not elaborated here, because
3805 their use may appear before the base type is frozen and it is
3806 not clear that they are needed in gigi. With the current model,
3807 there is no correct place where they could be elaborated. */
3812 {
3813 /* If we are to defer elaborating incomplete types, make a dummy
3814 type node and elaborate it later. */
3816 {
3819 p->old_type
3824 }
3829 }
3832 /* Subprogram Entities
3834 The following access functions are defined for subprograms:
3836 Etype Return type or Standard_Void_Type.
3837 First_Formal The first formal parameter.
3838 Is_Imported Indicates that the subprogram has appeared in
3839 an INTERFACE or IMPORT pragma. For now we
3840 assume that the external language is C.
3841 Is_Exported Likewise but for an EXPORT pragma.
3842 Is_Inlined True if the subprogram is to be inlined.
3844 Each parameter is first checked by calling must_pass_by_ref on its
3845 type to determine if it is passed by reference. For parameters which
3846 are copied in, if they are Ada In Out or Out parameters, their return
3847 value becomes part of a record which becomes the return type of the
3848 function (C function - note that this applies only to Ada procedures
3849 so there is no Ada return type). Additional code to store back the
3850 parameters will be generated on the caller side. This transformation
3851 is done here, not in the front-end.
3853 The intended result of the transformation can be seen from the
3854 equivalent source rewritings that follow:
3856 struct temp {int a,b};
3857 procedure P (A,B: In Out ...) is temp P (int A,B)
3858 begin {
3859 .. ..
3860 end P; return {A,B};
3861 }
3863 temp t;
3864 P(X,Y); t = P(X,Y);
3865 X = t.a , Y = t.b;
3867 For subprogram types we need to perform mainly the same conversions to
3868 GCC form that are needed for procedures and function declarations. The
3869 only difference is that at the end, we make a type declaration instead
3870 of a function declaration. */
3875 {
3876 tree gnu_ext_name
3878 enum inline_status_t inline_status
3880 ? is_suppressed
3882 ? is_required
3885 /* Subprograms marked both Intrinsic and Always_Inline need not
3886 have a body of their own. */
3887 bool extern_flag
3889 || imported_p
3892 tree gnu_param_list;
3894 /* A parameter may refer to this type, so defer completion of any
3895 incomplete types. */
3897 {
3898 defer_incomplete_level++;
3900 }
3902 /* If the subprogram has an alias, it is probably inherited, so
3903 we can use the original one. If the original "subprogram"
3904 is actually an enumeration literal, it may be the first use
3905 of its type, so we must elaborate that type now. */
3907 {
3914 gnu_decl
3917 /* Elaborate any Itypes in the parameters of this entity. */
3924 /* Materialize renamed subprograms in the debugging information
3925 when the renamed object is compile time known. We can consider
3926 such renamings as imported declarations.
3928 Because the parameters in generics instantiation are generally
3929 materialized as renamings, we ofter end up having both the
3930 renamed subprogram and the renaming in the same context and with
3931 the same name: in this case, renaming is both useless debug-wise
3932 and potentially harmful as name resolution in the debugger could
3933 return twice the same entity! So avoid this case. */
3942 && gnu_decl
3944 {
3949 }
3952 }
3954 /* Get the GCC tree for the (underlying) subprogram type. If the
3955 entity is an actual subprogram, also get the parameter list. */
3956 gnu_type
3960 {
3964 }
3966 /* Deal with platform-specific calling conventions. */
3968 prepend_one_attribute
3971 gnat_entity);
3973 prepend_one_attribute
3976 gnat_entity);
3978 /* If we should request stack realignment for a foreign convention
3979 subprogram, do so. Note that this applies to task entry points
3980 in particular. */
3982 prepend_one_attribute
3985 gnat_entity);
3987 /* Deal with a pragma Linker_Section on a subprogram. */
3993 /* If we are defining the subprogram and it has an Address clause
3994 we must get the address expression from the saved GCC tree for the
3995 subprogram if it has a Freeze_Node. Otherwise, we elaborate
3996 the address expression here since the front-end has guaranteed
3997 in that case that the elaboration has no effects. If there is
3998 an Address clause and we are not defining the object, just
3999 make it a constant. */
4001 {
4005 gnu_address
4012 /* Convert the type of the object to a reference type that can
4013 alias everything as per RM 13.3(19). */
4014 gnu_type
4019 gnu_decl
4025 }
4027 /* If this is a mere subprogram type, just create the declaration. */
4029 {
4032 gnu_decl
4035 }
4037 /* Otherwise create the subprogram declaration with the external name,
4038 the type and the parameter list. However, if this a reference to
4039 the allocation routines, reuse the canonical declaration nodes as
4040 they come with special properties. */
4041 else
4042 {
4047 else
4048 {
4049 gnu_decl
4054 debug_info_p,
4056 gnat_entity);
4060 }
4061 }
4062 }
4073 {
4074 const bool is_from_limited_with
4076 /* Get the "full view" of this entity. If this is an incomplete
4077 entity from a limited with, treat its non-limited view as the
4078 full view. Otherwise, use either the full view or the underlying
4079 full view, whichever is present. This is used in all the tests
4080 below. */
4081 const Entity_Id full_view
4082 = is_from_limited_with
4090 /* If this is an incomplete type with no full view, it must be a Taft
4091 Amendment type or an incomplete type coming from a limited context,
4092 in which cases we return a dummy type. Otherwise, we just get the
4093 type from its Etype. */
4095 {
4097 {
4100 }
4101 else
4102 {
4103 gnu_decl
4106 }
4107 }
4109 /* Or else, if we already made a type for the full view, reuse it. */
4113 /* Or else, if we are not defining the type or there is no freeze
4114 node on it, get the type for the full view. Likewise if this is
4115 a limited_with'ed type not declared in the main unit, which can
4116 happen for incomplete formal types instantiated on a type coming
4117 from a limited_with clause. */
4120 || (is_from_limited_with
4122 {
4125 }
4127 /* Otherwise, make a dummy type entry which will be replaced later.
4128 Save it as the full declaration's type so we can do any needed
4129 updates when we see it. */
4130 else
4131 {
4137 }
4138 }
4142 /* Class-wide types are always transformed into their root type. */
4151 /* If we are just annotating types and have no equivalent record type,
4152 just return void_type, except for root types that have discriminants
4153 because the discriminants will very likely be used in the declarative
4154 part of the associated body so they need to be translated. */
4156 {
4159 {
4161 Entity_Id gnat_field;
4163 /* This is a minimal version of the E_Record_Type handling. */
4170 {
4171 tree gnu_field
4183 }
4187 }
4188 else
4190 }
4192 /* Concurrent types are always transformed into their record type. */
4193 else
4204 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4205 we've already saved it, so we don't try to. */
4211 /* This is a SPARK annotation that only reaches here when compiling in
4212 ASIS mode. */
4220 }
4222 /* If we had a case where we evaluated another type and it might have
4223 defined this one, handle it here. */
4225 {
4228 }
4230 /* If we are processing a type and there is either no decl for it or
4231 we just made one, do some common processing for the type, such as
4232 handling alignment and possible padding. */
4234 {
4237 /* Process the attributes, if not already done. Note that the type is
4238 already defined so we cannot pass true for IN_PLACE here. */
4241 /* ??? Don't set the size for a String_Literal since it is either
4242 confirming or we don't handle it properly (if the low bound is
4243 non-constant). */
4245 {
4248 gnu_size
4251 }
4253 /* If a size was specified, see if we can make a new type of that size
4254 by rearranging the type, for example from a fat to a thin pointer. */
4256 {
4257 gnu_type
4264 }
4266 /* If the alignment has not already been processed and this is not
4267 an unconstrained array type, see if an alignment is specified.
4268 If not, we pick a default alignment for atomic objects. */
4270 ;
4272 {
4276 /* Warn on suspiciously large alignments. This should catch
4277 errors about the (alignment,byte)/(size,bit) discrepancy. */
4279 {
4280 tree size;
4282 /* If a size was specified, take it into account. Otherwise
4283 use the RM size for records or unions as the type size has
4284 already been adjusted to the alignment. */
4290 else
4293 /* Consider an alignment as suspicious if the alignment/size
4294 ratio is greater or equal to the byte/bit ratio. */
4299 gnat_entity);
4300 }
4301 }
4312 /* See if we need to pad the type. If we did, and made a record,
4313 the name of the new type may be changed. So get it back for
4314 us when we make the new TYPE_DECL below. */
4322 /* Now set the RM size of the type. We cannot do it before padding
4323 because we need to accept arbitrary RM sizes on integral types. */
4326 /* If we are at global level, GCC will have applied variable_size to
4327 the type, but that won't have done anything. So, if it's not
4328 a constant or self-referential, call elaborate_expression_1 to
4329 make a variable for the size rather than calculating it each time.
4330 Handle both the RM size and the actual size. */
4335 {
4342 /* ??? For now, store the size as a multiple of the alignment in
4343 bytes so that we can see the alignment from the tree. */
4349 /* ??? gnu_type may come from an existing type so the MULT_EXPR node
4350 may not be marked by the call to create_type_decl below. */
4354 {
4359 {
4363 /* If the position of the variant part is constant, subtract
4364 it from the size of the type of the parent to get the new
4365 size. This manual CSE reduces the data size. */
4367 {
4375 }
4376 else
4377 {
4383 /* ??? For now, store the size as a multiple of the
4384 alignment in bytes so that we can see the alignment
4385 from the tree. */
4392 /* ??? For now, store the offset as a multiple of the
4393 alignment in bytes so that we can see the alignment
4394 from the tree. */
4398 DECL_OFFSET_ALIGN
4400 }
4404 }
4408 else
4409 ada_size
4413 }
4414 }
4416 /* Similarly, if this is a record type or subtype at global level, call
4417 elaborate_expression_2 on any field position. Skip any fields that
4418 we haven't made trees for to avoid problems with class-wide types. */
4423 {
4426 /* ??? For now, store the offset as a multiple of the alignment
4427 in bytes so that we can see the alignment from the tree. */
4430 {
4437 /* ??? The context of gnu_field is not necessarily gnu_type
4438 so the MULT_EXPR node built above may not be marked by
4439 the call to create_type_decl below. */
4441 }
4442 }
4447 /* If this is not an unconstrained array type, set some flags. */
4449 {
4450 /* Tell the middle-end that objects of tagged types are guaranteed to
4451 be properly aligned. This is necessary because conversions to the
4452 class-wide type are translated into conversions to the root type,
4453 which can be less aligned than some of its derived types. */
4458 /* Record whether the type is passed by reference. */
4462 /* Record whether an alignment clause was specified. */
4466 /* Record whether a pragma Universal_Aliasing was specified. */
4470 /* If it is passed by reference, force BLKmode to ensure that
4471 objects of this type will always be put in memory. */
4474 }
4476 /* If this is a derived type, relate its alias set to that of its parent
4477 to avoid troubles when a call to an inherited primitive is inlined in
4478 a context where a derived object is accessed. The inlined code works
4479 on the parent view so the resulting code may access the same object
4480 using both the parent and the derived alias sets, which thus have to
4481 conflict. As the same issue arises with component references, the
4482 parent alias set also has to conflict with composite types enclosing
4483 derived components. For instance, if we have:
4485 type D is new T;
4486 type R is record
4487 Component : D;
4488 end record;
4490 we want T to conflict with both D and R, in addition to R being a
4491 superset of D by record/component construction.
4493 One way to achieve this is to perform an alias set copy from the
4494 parent to the derived type. This is not quite appropriate, though,
4495 as we don't want separate derived types to conflict with each other:
4497 type I1 is new Integer;
4498 type I2 is new Integer;
4500 We want I1 and I2 to both conflict with Integer but we do not want
4501 I1 to conflict with I2, and an alias set copy on derivation would
4502 have that effect.
4504 The option chosen is to make the alias set of the derived type a
4505 superset of that of its parent type. It trivially fulfills the
4506 simple requirement for the Integer derivation example above, and
4507 the component case as well by superset transitivity:
4509 superset superset
4510 R ----------> D ----------> T
4512 However, for composite types, conversions between derived types are
4513 translated into VIEW_CONVERT_EXPRs so a sequence like:
4515 type Comp1 is new Comp;
4516 type Comp2 is new Comp;
4517 procedure Proc (C : Comp1);
4519 C : Comp2;
4520 Proc (Comp1 (C));
4522 is translated into:
4524 C : Comp2;
4525 Proc ((Comp1 &) &VIEW_CONVERT_EXPR <Comp1> (C));
4527 and gimplified into:
4529 C : Comp2;
4530 Comp1 *C.0;
4531 C.0 = (Comp1 *) &C;
4532 Proc (C.0);
4534 i.e. generates code involving type punning. Therefore, Comp1 needs
4535 to conflict with Comp2 and an alias set copy is required.
4537 The language rules ensure the parent type is already frozen here. */
4541 {
4543 /* For constrained packed array subtypes, the implementation type is
4544 used instead of the nominal type. */
4552 }
4554 /* Finally get to the appropriate variant, except for the implementation
4555 type of a packed array because the GNU type might be further adjusted
4556 when the original array type is itself processed. */
4559 {
4560 const int quals
4561 = TYPE_QUAL_VOLATILE
4564 }
4566 /* If we already made a decl, just set the type, otherwise create it. */
4568 {
4571 }
4572 else
4575 }
4577 /* If we got a type that is not dummy, back-annotate the alignment of the
4578 type if not already in the tree. Likewise for the size, if any. */
4580 {
4584 {
4588 /* If the default alignment of "double" or larger scalar types is
4589 specifically capped and this is not an array with an alignment
4590 clause on the component type, return the cap. */
4592 is_capped_double
4595 is_capped_double
4597 else
4602 else
4606 }
4609 {
4612 /* If the size is self-referential, annotate the maximum value. */
4616 /* If we are just annotating types and the type is tagged, the tag
4617 and the parent components are not generated by the front-end so
4618 alignment and sizes must be adjusted if there is no rep clause. */
4625 {
4626 tree offset;
4629 {
4633 }
4634 else
4635 {
4636 unsigned int align
4640 }
4643 offset
4651 }
4653 /* If there is a rep clause, only adjust alignment and Esize. */
4655 {
4656 unsigned int align
4661 }
4663 /* Otherwise no adjustment is needed. */
4664 else
4666 }
4670 }
4672 /* If we haven't already, associate the ..._DECL node that we just made with
4673 the input GNAT entity node. */
4677 /* Now we are sure gnat_entity has a corresponding ..._DECL node,
4678 eliminate as many deferred computations as possible. */
4681 /* If this is an enumeration or floating-point type, we were not able to set
4682 the bounds since they refer to the type. These are always static. */
4685 {
4689 /* If this is a padded type, we need to use the underlying type. */
4693 /* If this is a floating point type and we haven't set a floating
4694 point type yet, use this in the evaluation of the bounds. */
4702 {
4703 /* Enumeration types have specific RM bounds. */
4706 }
4707 else
4708 {
4709 /* Floating-point types don't have specific RM bounds. */
4712 }
4713 }
4715 /* If we deferred processing of incomplete types, re-enable it. If there
4716 were no other disables and we have deferred types to process, do so. */
4720 {
4723 /* We are back to level 0 for the deferring of incomplete types.
4724 But processing these incomplete types below may itself require
4725 deferring, so preserve what we have and restart from scratch. */
4730 {
4737 }
4738 }
4740 /* If we are not defining this type, see if it's on one of the lists of
4741 incomplete types. If so, handle the list entry now. */
4743 {
4748 {
4752 }
4758 {
4764 }
4765 }
4768 force_global--;
4770 /* If this is a packed array type whose original array type is itself
4771 an Itype without freeze node, make sure the latter is processed. */
4779 }
4781 /* Similar, but if the returned value is a COMPONENT_REF, return the
4782 FIELD_DECL. */
4784 tree
4786 {
4793 }
4795 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
4796 the GCC type corresponding to that entity. */
4798 tree
4800 {
4801 tree gnu_decl;
4803 /* The back end never attempts to annotate generic types. */
4811 }
4813 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
4814 the unpadded version of the GCC type corresponding to that entity. */
4816 tree
4818 {
4825 }
4827 /* Return whether the E_Subprogram_Type/E_Function/E_Procedure GNAT_ENTITY is
4828 a C++ imported method or equivalent.
4830 We use the predicate on 32-bit x86/Windows to find out whether we need to
4831 use the "thiscall" calling convention for GNAT_ENTITY. This convention is
4832 used for C++ methods (functions with METHOD_TYPE) by the back-end. */
4834 bool
4836 {
4837 /* A constructor is a method on the C++ side. We deal with it now because
4838 it is declared without the 'this' parameter in the sources and, although
4839 the front-end will create a version with the 'this' parameter for code
4840 generation purposes, we want to return true for both versions. */
4844 /* Check that the subprogram has C++ convention. */
4848 /* And that the type of the first parameter (indirectly) has it too. */
4859 /* This is the main case: a C++ virtual method imported as a primitive
4860 operation of a tagged type. */
4864 /* This is set on the E_Subprogram_Type built for a dispatching call. */
4868 /* A thunk needs to be handled like its associated primitive operation. */
4872 /* Now on to the annoying case: a C++ non-virtual method, imported either
4873 as a non-primitive operation of a tagged type or as a primitive operation
4874 of an untagged type. We cannot reliably differentiate these cases from
4875 their static member or regular function equivalents in Ada, so we ask
4876 the C++ side through the mangled name of the function, as the implicit
4877 'this' parameter is not encoded in the mangled name of a method. */
4879 {
4886 DMGL_GNU_V3
4887 | DMGL_TYPES
4888 | DMGL_PARAMS
4894 /* We need to release MEM once we have a successful demangling. */
4901 {
4902 /* Make sure there is at least one parameter in C++ too. */
4904 {
4907 n_ada_args++;
4913 n_cpp_args++;
4919 }
4920 else
4922 }
4927 }
4930 }
4932 /* Finalize the processing of From_Limited_With incomplete types. */
4934 void
4936 {
4943 {
4947 {
4952 }
4955 }
4956 }
4958 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a kind
4959 of type (such E_Task_Type) that has a different type which Gigi uses
4960 for its representation. If the type does not have a special type for
4961 its representation, return GNAT_ENTITY. */
4963 Entity_Id
4965 {
4972 {
4998 }
5001 }
5003 /* Return a GCC tree for a type corresponding to the component type of the
5004 array type or subtype GNAT_ARRAY. DEFINITION is true if this component
5005 is for an array being defined. DEBUG_INFO_P is true if we need to write
5006 debug information for other types that we may create in the process. */
5008 static tree
5011 {
5014 tree gnu_comp_size;
5017 /* If an alignment is specified, use it as a cap on the component type
5018 so that it can be honored for the whole type. But ignore it for the
5019 original type of packed array types. */
5023 else
5026 /* Try to get a smaller form of the component if needed. */
5036 /* Get and validate any specified Component_Size. */
5037 gnu_comp_size
5042 /* If the component type is a RECORD_TYPE that has a self-referential size,
5043 then use the maximum size for the component size. */
5049 /* If the array has aliased components and the component size is zero, force
5050 the unit size to ensure that the components have distinct addresses. */
5056 /* Honor the component size. This is not needed for bit-packed arrays. */
5058 {
5064 else
5070 /* If a padding record was made, declare it now since it will never be
5071 declared otherwise. This is necessary to ensure that its subtrees
5072 are properly marked. */
5075 gnat_array);
5076 }
5078 /* This is a very special case where the array has aliased components and the
5079 component size might be zero at run time. As explained above, we force at
5080 least the unit size but we don't want to build a distinct padding type for
5081 each invocation (they are not canonicalized if they have variable size) so
5082 we cache this special padding type as TYPE_PADDING_FOR_COMPONENT. */
5086 {
5089 else
5090 {
5091 gnu_comp_size
5098 gnat_array);
5099 }
5100 }
5105 /* If the component type is a padded type made for a non-bit-packed array
5106 of scalars with reverse storage order, we need to propagate the reverse
5107 storage order to the padding type since it is the innermost enclosing
5108 aggregate type around the scalar. */
5116 {
5117 const int quals
5118 = TYPE_QUAL_VOLATILE
5121 }
5124 }
5126 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM, to be placed
5127 in the parameter list of GNAT_SUBPROG. GNU_PARAM_TYPE is the GCC tree for
5128 the type of the parameter. FIRST is true if this is the first parameter in
5129 the list of GNAT_SUBPROG. Also set CICO to true if the parameter must use
5130 the copy-in copy-out implementation mechanism.
5132 The returned tree is a PARM_DECL, except for the cases where no parameter
5133 needs to be actually passed to the subprogram; the type of this "shadow"
5134 parameter is then returned instead. */
5136 static tree
5139 {
5145 /* The parameter can be indirectly modified if its address is taken. */
5151 tree gnu_param;
5153 /* Make sure to use the proper SLOC for vector ABI warnings. */
5157 /* Builtins are expanded inline and there is no real call sequence involved.
5158 So the type expected by the underlying expander is always the type of the
5159 argument "as is". */
5164 /* Handle the first parameter of a valued procedure specially: it's a copy
5165 mechanism for which the parameter is never allocated. */
5167 {
5171 }
5173 /* Or else, see if a Mechanism was supplied that forced this parameter
5174 to be passed one way or another. */
5176 ;
5178 /* Positive mechanism means by copy for sufficiently small parameters. */
5180 {
5185 else
5187 }
5189 /* Otherwise, it's an unsupported mechanism so error out. */
5190 else
5191 {
5194 }
5196 /* If this is either a foreign function or if the underlying type won't
5197 be passed by reference and is as aligned as the original type, strip
5198 off possible padding type. */
5200 {
5209 }
5211 /* If this is a read-only parameter, make a variant of the type that is
5212 read-only. ??? However, if this is a self-referential type, the type
5213 can be very complex, so skip it for now. */
5217 /* For foreign conventions, pass arrays as pointers to the element type.
5218 First check for unconstrained array and get the underlying array. */
5220 gnu_param_type
5223 /* Arrays are passed as pointers to element type for foreign conventions. */
5225 {
5226 /* Strip off any multi-dimensional entries, then strip
5227 off the last array to get the component type. */
5236 gnu_param_type
5240 }
5242 /* Fat pointers are passed as thin pointers for foreign conventions. */
5244 gnu_param_type
5247 /* If we were requested or muss pass by reference, do so.
5248 If we were requested to pass by copy, do so.
5249 Otherwise, for foreign conventions, pass In Out or Out parameters
5250 or aggregates by reference. For COBOL and Fortran, pass all
5251 integer and FP types that way too. For Convention Ada, use
5252 the standard Ada default. */
5256 && ((foreign
5258 || (foreign
5263 || (!foreign
5265 {
5266 /* We take advantage of 6.2(12) by considering that references built for
5267 parameters whose type isn't by-ref and for which the mechanism hasn't
5268 been forced to by-ref allow only a restricted form of aliasing. */
5269 restricted_aliasing_p
5273 }
5275 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
5284 /* If this is an Out parameter that isn't passed by reference and isn't
5285 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
5286 it will be a VAR_DECL created when we process the procedure, so just
5287 return its type. For the special parameter of a valued procedure,
5288 never pass it in.
5290 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
5291 Out parameters with discriminants or implicit initial values to be
5292 handled like In Out parameters. These type are normally built as
5293 aggregates, hence passed by reference, except for some packed arrays
5294 which end up encoded in special integer types. Note that scalars can
5295 be given implicit initial values using the Default_Value aspect.
5297 The exception we need to make is then for packed arrays of records
5298 with discriminants or implicit initial values. We have no light/easy
5299 way to check for the latter case, so we merely check for packed arrays
5300 of records. This may lead to useless copy-in operations, but in very
5301 rare cases only, as these would be exceptions in a set of already
5302 exceptional situations. */
5304 && !by_ref
5305 && (by_return
5324 /* If no Mechanism was specified, indicate what we're using, then
5325 back-annotate it. */
5331 }
5333 /* Associate GNAT_SUBPROG with GNU_TYPE, which must be a dummy type, so that
5334 GNAT_SUBPROG is updated when GNU_TYPE is completed.
5336 Ada 2012 (AI05-019) says that freezing a subprogram does not always freeze
5337 the corresponding profile, which means that, by the time the freeze node
5338 of the subprogram is encountered, types involved in its profile may still
5339 be not yet frozen. That's why we need to update GNAT_SUBPROG when we see
5340 the freeze node of types involved in its profile, either types of formal
5341 parameters or the return type. */
5343 static void
5345 {
5353 {
5358 }
5360 /* Even if there is already a slot for GNU_TYPE, we need to set the flag
5361 because the vector might have been just emptied by update_profiles_with.
5362 This can happen when there are 2 freeze nodes associated with different
5363 views of the same type; the type will be really complete only after the
5364 second freeze node is encountered. */
5369 /* Make sure GNAT_SUBPROG is not associated twice with the same dummy type,
5370 since this would mean updating twice its profile. */
5372 {
5376 /* Entity_Id is a simple integer so we can implement a stable order on
5377 the vector with an ordered insertion scheme and binary search. */
5379 {
5386 else
5388 }
5390 /* l == u and therefore is the insertion point. */
5392 }
5393 else
5397 }
5399 /* Update the GCC tree previously built for the profile of GNAT_SUBPROG. */
5401 static void
5403 {
5404 tree gnu_param_list;
5409 {
5410 /* Builtins cannot have their address taken so we can reset them. */
5415 }
5421 /* If GNAT_SUBPROG is an actual subprogram, GNU_SUBPROG is a FUNCTION_DECL
5422 and needs to be adjusted too. */
5424 {
5426 tree gnu_ext_name
5431 }
5432 }
5434 /* Update the GCC trees previously built for the profiles involving GNU_TYPE,
5435 a dummy type which appears in profiles. */
5437 void
5439 {
5447 /* The flag needs to be reset before calling update_profile, in case
5448 associate_subprog_with_dummy_type is again invoked on GNU_TYPE. */
5457 }
5459 /* Return the GCC tree for GNAT_TYPE present in the profile of a subprogram.
5461 Ada 2012 (AI05-0151) says that incomplete types coming from a limited
5462 context may now appear as parameter and result types. As a consequence,
5463 we may need to defer their translation until after a freeze node is seen
5464 or to the end of the current unit. We also aim at handling temporarily
5465 incomplete types created by the usual delayed elaboration scheme. */
5467 static tree
5469 {
5470 /* This is the same logic as the E_Access_Type case of gnat_to_gnu_entity
5471 so the rationale is exposed in that place. These processings probably
5472 ought to be merged at some point. */
5474 const bool is_from_limited_with
5477 Entity_Id gnat_full_direct_first
5478 = (is_from_limited_with
5482 Entity_Id gnat_full_direct
5483 = ((is_from_limited_with
5491 tree gnu_type;
5497 && ((!in_main_unit
5504 {
5508 {
5515 }
5516 }
5521 else
5524 /* Access-to-unconstrained-array types need a special treatment. */
5526 {
5529 }
5532 }
5534 /* Return a GCC tree for a subprogram type corresponding to GNAT_SUBPROG.
5535 DEFINITION is true if this is for a subprogram being defined. DEBUG_INFO_P
5536 is true if we need to write debug information for other types that we may
5537 create in the process. Also set PARAM_LIST to the list of parameters.
5538 If GNAT_SUBPROG is bound to a GCC builtin, return the DECL for the builtin
5539 directly instead of its type. */
5541 static tree
5544 {
5547 Entity_Id gnat_param;
5550 tree gnu_return_type;
5553 /* Non-null for subprograms containing parameters passed by copy-in copy-out
5554 (In Out or Out parameters not passed by reference), in which case it is
5555 the list of nodes used to specify the values of the In Out/Out parameters
5556 that are returned as a record upon procedure return. The TREE_PURPOSE of
5557 an element of this list is a FIELD_DECL of the record and the TREE_VALUE
5558 is the PARM_DECL corresponding to that field. This list will be saved in
5559 the TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
5562 /* Fields in return type of procedure with copy-in copy-out parameters. */
5564 /* The semantics of "pure" in Ada essentially matches that of "const"
5565 in the back-end. In particular, both properties are orthogonal to
5566 the "nothrow" property if the EH circuitry is explicit in the
5567 internal representation of the back-end. If we are to completely
5568 hide the EH circuitry from it, we need to declare that calls to pure
5569 Ada subprograms that can throw have side effects since they can
5570 trigger an "abnormal" transfer of control flow; thus they can be
5571 neither "const" nor "pure" in the back-end sense. */
5579 /* Look into the return type and get its associated GCC tree if it is not
5580 void, and then compute various flags for the subprogram type. But make
5581 sure not to do this processing multiple times. */
5588 {
5593 }
5595 else
5596 {
5597 /* For foreign convention subprograms, return System.Address as void *
5598 or equivalent. Note that this comprises GCC builtins. */
5602 else
5605 /* If this function returns by reference, make the actual return type
5606 the reference type and make a note of that. */
5608 {
5611 }
5613 /* If the return type is an unconstrained array type, the return value
5614 will be allocated on the secondary stack so the actual return type
5615 is the fat pointer type. */
5617 {
5620 }
5622 /* This is the same unconstrained array case, but for a dummy type. */
5625 {
5628 }
5630 /* Likewise, if the return type requires a transient scope, the return
5631 value will also be allocated on the secondary stack so the actual
5632 return type is the reference type. */
5634 {
5637 }
5639 /* If the Mechanism is By_Reference, ensure this function uses the
5640 target's by-invisible-reference mechanism, which may not be the
5641 same as above (e.g. it might be passing an extra parameter). */
5645 /* Likewise, if the return type is itself By_Reference. */
5649 /* If the type is a padded type and the underlying type would not be
5650 passed by reference or the function has a foreign convention, return
5651 the underlying type. */
5653 && (!default_pass_by_ref
5658 /* If the return type is unconstrained, it must have a maximum size.
5659 Use the padded type as the effective return type. And ensure the
5660 function uses the target's by-invisible-reference mechanism to
5661 avoid copying too much data when it returns. */
5663 {
5667 /* If the size overflows to 0, set it to an arbitrary positive
5668 value so that assignments in the type are preserved. Their
5669 actual size is independent of this positive value. */
5673 {
5676 }
5682 /* Declare it now since it will never be declared otherwise. This
5683 is necessary to ensure that its subtrees are properly marked. */
5690 }
5692 /* If the return type has a size that overflows, we usually cannot have
5693 a function that returns that type. This usage doesn't really make
5694 sense anyway, so issue an error here. */
5699 {
5704 }
5706 /* If the return type is incomplete, there are 2 cases: if the function
5707 returns by reference, then the return type is only linked indirectly
5708 in the profile, so the profile can be seen as complete since it need
5709 not be further modified, only the reference types need be adjusted;
5710 otherwise the profile is incomplete and need be adjusted too. */
5712 {
5715 }
5719 || return_by_direct_ref_p
5720 || return_by_invisi_ref_p
5722 }
5724 /* A procedure (something that doesn't return anything) shouldn't be
5725 considered const since there would be no reason for calling such a
5726 subprogram. Note that procedures with Out (or In Out) parameters
5727 have already been converted into a function with a return type.
5728 Similarly, if the function returns an unconstrained type, then the
5729 function will allocate the return value on the secondary stack and
5730 thus calls to it cannot be CSE'ed, lest the stack be reclaimed. */
5734 /* Loop over the parameters and get their associated GCC tree. While doing
5735 this, build a copy-in copy-out structure if we need one. */
5739 {
5740 const bool mech_is_by_ref
5747 /* Fetch an existing parameter with complete type and reuse it. But we
5748 didn't save the CICO property so we can only do it for In parameters
5749 or parameters passed by reference. */
5754 {
5757 }
5759 /* Otherwise translate the parameter type and act accordingly. */
5760 else
5761 {
5764 /* For foreign convention subprograms, pass System.Address as void *
5765 or equivalent. Note that this comprises GCC builtins. */
5769 else
5772 /* If the parameter type is incomplete, there are 2 cases: if it is
5773 passed by reference, then the type is only linked indirectly in
5774 the profile, so the profile can be seen as complete since it need
5775 not be further modified, only the reference type need be adjusted;
5776 otherwise the profile is incomplete and need be adjusted too. */
5778 {
5779 Node_Id gnat_decl;
5783 && TYPE_IS_FAT_POINTER_P
5786 {
5788 gnu_param
5798 }
5800 /* ??? This is a kludge to support null procedures in spec taking
5801 a parameter with an untagged incomplete type coming from a
5802 limited context. The front-end creates a body without knowing
5803 anything about the non-limited view, which is illegal Ada and
5804 cannot be supported. Create a parameter with a fake type. */
5812 else
5813 {
5814 /* Build a minimal PARM_DECL without DECL_ARG_TYPE so that
5815 Call_to_gnu will stop if it encounters the PARM_DECL. */
5816 gnu_param
5818 gnu_param_type);
5820 gnu_param_type);
5822 }
5823 }
5825 /* Otherwise build the parameter declaration normally. */
5826 else
5827 {
5828 gnu_param
5832 /* We are returned either a PARM_DECL or a type if no parameter
5833 needs to be passed; in either case, adjust the type. */
5836 else
5837 {
5840 }
5841 }
5842 }
5844 /* If we have a GCC tree for the parameter, register it. */
5847 {
5848 gnu_param_type_list
5853 /* If a parameter is a pointer, a function may modify memory through
5854 it and thus shouldn't be considered a const function. Also, the
5855 memory may be modified between two calls, so they can't be CSE'ed.
5856 The latter case also handles by-ref parameters. */
5860 }
5862 /* If the parameter uses the copy-in copy-out mechanism, allocate a field
5863 for it in the return type and register the association. */
5865 {
5867 {
5870 /* If this is a function, we also need a field for the
5871 return value to be placed. */
5873 {
5874 tree gnu_field
5876 gnu_return_type,
5882 gnu_cico_list
5884 }
5887 /* Set a default alignment to speed up accesses. But we should
5888 not increase the size of the structure too much, lest it does
5889 not fit in return registers anymore. */
5892 }
5894 tree gnu_field
5903 }
5904 }
5906 /* If the subprogram uses the copy-in copy-out mechanism, possibly adjust
5907 and finish up the return type. */
5909 {
5910 /* If we have a CICO list but it has only one entry, we convert
5911 this function into a function that returns this object. */
5915 /* Do not finalize the return type if the subprogram is stubbed
5916 since structures are incomplete for the back-end. */
5918 {
5922 /* Try to promote the mode of the return type if it is passed
5923 in registers, again to speed up accesses. */
5926 NULL_TREE))
5927 {
5928 unsigned int size
5931 scalar_int_mode mode;
5936 {
5944 }
5945 }
5949 }
5952 }
5954 /* The lists have been built in reverse. */
5960 /* If the profile is incomplete, we only set the (temporary) return and
5961 parameter types; otherwise, we build the full type. In either case,
5962 we reuse an already existing GCC tree that we built previously here. */
5964 {
5966 ;
5967 else
5974 }
5975 else
5976 {
5978 {
5987 }
5988 else
5989 {
5990 gnu_type
5993 /* GNU_TYPE may be shared since GCC hashes types. Unshare it if it
5994 has a different TYPE_CI_CO_LIST or flags. */
5996 return_unconstrained_p,
5997 return_by_direct_ref_p,
5998 return_by_invisi_ref_p))
5999 {
6005 }
6006 }
6014 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
6015 corresponding DECL node and check the parameter association. */
6018 {
6022 /* If we have a builtin DECL for that function, use it. Check if
6023 the profiles are compatible and warn if they are not. Note that
6024 the checker is expected to post diagnostics in this case. */
6026 {
6027 intrin_binding_t inb
6031 post_error
6033 gnat_subprog);
6036 }
6038 /* Inability to find the builtin DECL most often indicates a genuine
6039 mistake, but imports of unregistered intrinsics are sometimes used
6040 on purpose to allow hooking in alternate bodies; we post a warning
6041 conditioned on Wshadow in this case, to let developers be notified
6042 on demand without risking false positives with common default sets
6043 of options. */
6046 }
6047 }
6050 }
6052 /* Return the external name for GNAT_SUBPROG given its entity name. */
6054 static tree
6056 {
6059 /* If there was no specified Interface_Name and the external and
6060 internal names of the subprogram are the same, only use the
6061 internal name to allow disambiguation of nested subprograms. */
6066 }
6068 /* Like build_qualified_type, but TYPE_QUALS is added to the existing
6069 qualifiers on TYPE. */
6071 static tree
6073 {
6074 /* Qualifiers must be put on the associated array type. */
6079 }
6081 /* Set TYPE_NONALIASED_COMPONENT on an array type built by means of
6082 build_nonshared_array_type. */
6084 static void
6086 {
6089 }
6091 /* Set TYPE_REVERSE_STORAGE_ORDER on an array type built by means of
6092 build_nonshared_array_type. */
6094 static void
6096 {
6099 }
6101 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
6103 static bool
6105 {
6112 return
6114 }
6116 /* Return true if the array type GNU_TYPE, which represents a dimension of
6117 GNAT_TYPE, has a non-aliased component in the back-end sense. */
6119 static bool
6121 {
6122 /* If the array type is not the innermost dimension of the GNAT type,
6123 then it has a non-aliased component. */
6128 /* If the array type has an aliased component in the front-end sense,
6129 then it also has an aliased component in the back-end sense. */
6133 /* If this is a derived type, then it has a non-aliased component if
6134 and only if its parent type also has one. */
6136 {
6140 gnu_parent_type
6145 }
6147 /* Consider that an array of pointers has an aliased component, which is
6148 sort of logical and helps with Taft Amendment types in LTO mode. */
6152 /* Otherwise, rely exclusively on properties of the element type. */
6154 }
6156 /* Return true if GNAT_ADDRESS is a value known at compile-time. */
6158 static bool
6160 {
6161 /* Handle reference to a constant. */
6164 {
6168 }
6170 /* Catch System'To_Address. */
6175 }
6177 /* Return true if GNAT_RANGE, a N_Range node, cannot be superflat, i.e. if the
6178 inequality HB >= LB-1 is true. LB and HB are the low and high bounds. */
6180 static bool
6182 {
6184 Node_Id scalar_range;
6187 /* If the low bound is not constant, try to find an upper bound. */
6196 /* If the high bound is not constant, try to find a lower bound. */
6205 /* If we have failed to find constant bounds, punt. */
6210 /* We need at least a signed 64-bit type to catch most cases. */
6216 /* If the low bound is the smallest integer, nothing can be smaller. */
6222 }
6224 /* Return true if GNU_EXPR is (essentially) the address of a CONSTRUCTOR. */
6226 static bool
6228 {
6236 }
6238 /* Return true if the size in units represented by GNU_SIZE can be handled by
6239 an allocation. If STATIC_P is true, consider only what can be done with a
6240 static allocation. */
6242 static bool
6244 {
6245 /* We can allocate a fixed size if it is a valid for the middle-end. */
6249 /* We can allocate a variable size if this isn't a static allocation. */
6250 else
6252 }
6254 /* Return true if GNU_EXPR needs a conversion to GNU_TYPE when used as the
6255 initial value of an object of GNU_TYPE. */
6257 static bool
6259 {
6260 /* Do not convert if the object's type is unconstrained because this would
6261 generate useless evaluations of the CONSTRUCTOR to compute the size. */
6266 /* Do not convert if the object's type is a padding record whose field is of
6267 self-referential size because we want to copy only the actual data. */
6271 /* Do not convert a call to a function that returns with variable size since
6272 we want to use the return slot optimization in this case. */
6277 /* Do not convert to a record type with a variant part from a record type
6278 without one, to keep the object simpler. */
6285 /* In all the other cases, convert the expression to the object's type. */
6287 }
6288 \f
6289 /* Given GNAT_ENTITY, elaborate all expressions that are required to
6290 be elaborated at the point of its definition, but do nothing else. */
6292 void
6294 {
6296 {
6303 {
6307 /* ??? Tests to avoid Constraint_Error in static expressions
6308 are needed until after the front stops generating bogus
6309 conversions on bounds of real types. */
6317 }
6324 {
6325 Node_Id gnat_discriminant_expr;
6326 Entity_Id gnat_field;
6330 gnat_discriminant_expr
6335 /* Ignore access discriminants. */
6340 }
6343 }
6344 }
6345 \f
6346 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
6347 NAME, ARGS and ERROR_POINT. */
6349 static void
6352 tree attr_name,
6353 tree attr_args,
6354 Node_Id attr_error_point)
6355 {
6365 }
6367 /* Prepend to ATTR_LIST an entry for an attribute provided by GNAT_PRAGMA. */
6369 static void
6371 {
6376 /* Map the pragma at hand. Skip if this isn't one we know how to handle. */
6378 {
6409 }
6411 /* See what arguments we have and turn them into GCC trees for attribute
6412 handlers. These expect identifier for strings. We handle at most two
6413 arguments and static expressions only. */
6415 {
6421 {
6425 {
6429 }
6432 }
6436 {
6441 }
6442 }
6444 /* Prepend to the list. Make a list of the argument we might have, as GCC
6445 expects it. */
6447 gnu_arg1
6451 }
6453 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
6455 static void
6457 {
6458 Node_Id gnat_temp;
6460 /* Attributes are stored as Representation Item pragmas. */
6466 }
6467 \f
6468 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
6469 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
6470 return the GCC tree to use for that expression. S is the suffix to use
6471 if a variable needs to be created and DEFINITION is true if this is done
6472 for a definition of GNAT_ENTITY. If NEED_VALUE is true, we need a result;
6473 otherwise, we are just elaborating the expression for side-effects. If
6474 NEED_DEBUG is true, we need a variable for debugging purposes even if it
6475 isn't needed for code generation. */
6477 static tree
6480 {
6481 tree gnu_expr;
6483 /* If we already elaborated this expression (e.g. it was involved
6484 in the definition of a private type), use the old value. */
6488 /* If we don't need a value and this is static or a discriminant,
6489 we don't need to do anything. */
6496 /* If it's a static expression, we don't need a variable for debugging. */
6500 /* Otherwise, convert this tree to its GCC equivalent and elaborate it. */
6504 /* Save the expression in case we try to elaborate this entity again. Since
6505 it's not a DECL, don't check it. Don't save if it's a discriminant. */
6510 }
6512 /* Similar, but take a GNU expression and always return a result. */
6514 static tree
6517 {
6522 /* If GNU_EXPR contains a placeholder, just return it. We rely on the fact
6523 that an expression cannot contain both a discriminant and a variable. */
6527 /* If GNU_EXPR is neither a constant nor based on a read-only variable, make
6528 a variable that is initialized to contain the expression when the package
6529 containing the definition is elaborated. If this entity is defined at top
6530 level, replace the expression by the variable; otherwise use a SAVE_EXPR
6531 if this is necessary. */
6534 else
6535 {
6536 /* Skip any conversions and simple constant arithmetics to see if the
6537 expression is based on a read-only variable. */
6545 expr_variable_p
6546 = !(inner
6549 }
6551 /* We only need to use the variable if we are in a global context since GCC
6552 can do the right thing in the local case. However, when not optimizing,
6553 use it for bounds of loop iteration scheme to avoid code duplication. */
6554 use_variable = expr_variable_p
6555 && (expr_global_p
6556 || (!optimize
6557 && definition
6562 /* Now create it, possibly only for debugging purposes. */
6564 {
6565 /* The following variable creation can happen when processing the body
6566 of subprograms that are defined out of the extended main unit and
6567 inlined. In this case, we are not at the global scope, and thus the
6568 new variable must not be tagged "external", as we used to do here as
6569 soon as DEFINITION was false. */
6570 tree gnu_decl
6577 /* Using this variable at debug time (if need_debug is true) requires a
6578 proper location. The back-end will compute a location for this
6579 variable only if the variable is used by the generated code.
6580 Returning the variable ensures the caller will use it in generated
6581 code. Note that there is no need for a location if the debug info
6582 contains an integer constant.
6583 TODO: when the encoding-based debug scheme is dropped, move this
6584 condition to the top-level IF block: we will not need to create a
6585 variable anymore in such cases, then. */
6588 }
6591 }
6593 /* Similar, but take an alignment factor and make it explicit in the tree. */
6595 static tree
6598 {
6600 return
6603 gnu_expr,
6604 unit_align),
6606 need_debug),
6607 unit_align);
6608 }
6610 /* Structure to hold internal data for elaborate_reference. */
6612 struct er_data
6613 {
6614 Entity_Id entity;
6617 };
6619 /* Wrapper function around elaborate_expression_1 for elaborate_reference. */
6621 static tree
6623 {
6627 /* This is what elaborate_expression_1 does if NEED_DEBUG is false. */
6631 /* If this is a COMPONENT_REF of a fat pointer, elaborate the entire fat
6632 pointer. This may be more efficient, but will also allow us to more
6633 easily find the match for the PLACEHOLDER_EXPR. */
6641 return
6643 }
6645 /* Elaborate the reference REF to be used as renamed object for GNAT_ENTITY.
6646 DEFINITION is true if this is done for a definition of GNAT_ENTITY and
6647 INIT is set to the first arm of a COMPOUND_EXPR present in REF, if any. */
6649 static tree
6652 {
6655 }
6656 \f
6657 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
6658 the value passed against the list of choices. */
6660 static tree
6662 {
6663 Node_Id choice;
6664 Node_Id gnat_temp;
6669 {
6671 {
6676 this_test
6691 this_test
6702 /* This represents either a subtype range, an enumeration
6703 literal, or a constant Ekind says which. If an enumeration
6704 literal or constant, fall through to the next case. */
6707 {
6713 this_test
6721 }
6723 /* ... fall through ... */
6738 }
6742 else
6745 }
6748 }
6749 \f
6750 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
6751 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
6753 static int
6755 {
6756 /* If the field contains an item of variable size, we cannot pack it
6757 because we cannot create temporaries of non-fixed size in case
6758 we need to take the address of the field. See addressable_p and
6759 the notes on the addressability issues for further details. */
6763 /* In the other cases, we can honor the packing. */
6767 /* If the alignment of the record is specified and the field type
6768 is over-aligned, request Storage_Unit alignment for the field. */
6773 /* Likewise if the maximum alignment of the record is specified. */
6779 }
6781 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
6782 placed in GNU_RECORD_TYPE.
6784 PACKED is 1 if the enclosing record is packed or -1 if the enclosing
6785 record has Component_Alignment of Storage_Unit.
6787 DEFINITION is true if this field is for a record being defined.
6789 DEBUG_INFO_P is true if we need to write debug information for types
6790 that we may create in the process. */
6792 static tree
6795 {
6798 const bool is_atomic
6801 const bool is_independent
6803 const bool is_volatile
6806 /* We used to consider that volatile fields also require strict alignment,
6807 but that was an interpolation and would cause us to reject a pragma
6808 volatile on a packed record type containing boolean components, while
6809 there is no basis to do so in the RM. In such cases, the writes will
6810 involve load-modify-store sequences, but that's OK for volatile. The
6811 only constraint is the implementation advice whereby only the bits of
6812 the components should be accessed if they both start and end on byte
6813 boundaries, but that should be guaranteed by the GCC memory model. */
6814 const bool needs_strict_alignment
6820 /* If this field requires strict alignment, we cannot pack it because
6821 it would very likely be under-aligned in the record. */
6824 else
6827 /* If a size is specified, use it. Otherwise, if the record type is packed,
6828 use the official RM size. See "Handling of Type'Size Values" in Einfo
6829 for further details. */
6836 else
6839 /* If we have a specified size that is smaller than that of the field's type,
6840 or a position is specified, and the field's type is a record that doesn't
6841 require strict alignment, see if we can get either an integral mode form
6842 of the type or a smaller form. If we can, show a size was specified for
6843 the field if there wasn't one already, so we know to make this a bitfield
6844 and avoid making things wider.
6846 Changing to an integral mode form is useful when the record is packed as
6847 we can then place the field at a non-byte-aligned position and so achieve
6848 tighter packing. This is in addition required if the field shares a byte
6849 with another field and the front-end lets the back-end handle the access
6850 to the field, because GCC cannot handle non-byte-aligned BLKmode fields.
6852 Changing to a smaller form is required if the specified size is smaller
6853 than that of the field's type and the type contains sub-fields that are
6854 padded, in order to avoid generating accesses to these sub-fields that
6855 are wider than the field.
6857 We avoid the transformation if it is not required or potentially useful,
6858 as it might entail an increase of the field's alignment and have ripple
6859 effects on the outer record type. A typical case is a field known to be
6860 byte-aligned and not to share a byte with another field. */
6866 || (gnu_size
6872 {
6875 {
6879 }
6880 }
6883 {
6884 const unsigned int align
6887 gnu_field_type
6891 }
6894 {
6902 /* Ensure the position does not overlap with the parent subtype, if there
6903 is one. This test is omitted if the parent of the tagged type has a
6904 full rep clause since, in this case, component clauses are allowed to
6905 overlay the space allocated for the parent type and the front-end has
6906 checked that there are no overlapping components. */
6908 {
6913 post_error_ne_tree
6916 }
6918 /* If this field needs strict alignment, make sure that the record is
6919 sufficiently aligned and that the position and size are consistent
6920 with the type. But don't do it if we are just annotating types and
6921 the field's type is tagged, since tagged types aren't fully laid out
6922 in this mode. Also, note that atomic implies volatile so the inner
6923 test sequences ordering is significant here. */
6926 {
6933 /* If the position is not a multiple of the alignment of the type,
6934 then error out and reset the position. */
6937 {
6949 else
6953 type_align);
6955 }
6958 {
6962 /* If the size is lower than that of the type, or greater for
6963 atomic and aliased, then error out and reset the size. */
6965 {
6977 else
6981 gnu_type_size);
6983 }
6985 /* Likewise if the size is not a multiple of a byte, */
6987 bitsize_unit_node)))
6988 {
6997 else
7002 }
7003 }
7004 }
7005 }
7007 /* If the record has rep clauses and this is the tag field, make a rep
7008 clause for it as well. */
7011 {
7014 }
7016 else
7017 {
7020 /* If we are packing the record and the field is BLKmode, round the
7021 size up to a byte boundary. */
7024 }
7026 /* We need to make the size the maximum for the type if it is
7027 self-referential and an unconstrained type. In that case, we can't
7028 pack the field since we can't make a copy to align it. */
7030 && !gnu_size
7033 {
7036 }
7038 /* If a size is specified, adjust the field's type to it. */
7040 {
7041 tree orig_field_type;
7043 /* If the field's type is justified modular, we would need to remove
7044 the wrapper to (better) meet the layout requirements. However we
7045 can do so only if the field is not aliased to preserve the unique
7046 layout, if it has the same storage order as the enclosing record
7047 and if the prescribed size is not greater than that of the packed
7048 array to preserve the justification. */
7058 /* Similarly if the field's type is a misaligned integral type, but
7059 there is no restriction on the size as there is no justification. */
7065 gnu_field_type
7073 /* If a padding record was made, declare it now since it will never be
7074 declared otherwise. This is necessary to ensure that its subtrees
7075 are properly marked. */
7080 }
7082 /* Otherwise (or if there was an error), don't specify a position. */
7083 else
7086 /* If the field's type is a padded type made for a scalar field of a record
7087 type with reverse storage order, we need to propagate the reverse storage
7088 order to the padding type since it is the innermost enclosing aggregate
7089 type around the scalar. */
7098 /* Now create the decl for the field. */
7099 gnu_field
7107 {
7112 }
7115 }
7116 \f
7117 /* Return true if at least one member of COMPONENT_LIST needs strict
7118 alignment. */
7120 static bool
7122 {
7123 Node_Id component_decl;
7128 {
7136 }
7139 }
7141 /* Return true if TYPE is a type with variable size or a padding type with a
7142 field of variable size or a record that has a field with such a type. */
7144 static bool
7146 {
7147 tree field;
7164 }
7165 \f
7166 /* Return true if FIELD is an artificial field. */
7168 static bool
7170 {
7171 /* These fields are generated by the front-end proper. */
7175 /* These fields are generated by gigi. */
7180 }
7182 /* Return true if FIELD is a non-artificial field with self-referential
7183 size. */
7185 static bool
7187 {
7195 }
7197 /* Return true if FIELD is a non-artificial field with variable size. */
7199 static bool
7201 {
7209 }
7211 /* qsort comparer for the bit positions of two record components. */
7213 static int
7215 {
7218 const int ret
7222 }
7224 /* Sort the LIST of fields in reverse order of increasing position. */
7226 static tree
7228 {
7238 {
7241 }
7244 }
7246 /* Reverse function from gnat_to_gnu_field: return the GNAT field present in
7247 either GNAT_COMPONENT_LIST or the discriminants of GNAT_RECORD_TYPE, and
7248 corresponding to the GNU tree GNU_FIELD. */
7250 static Entity_Id
7252 Entity_Id gnat_record_type)
7253 {
7261 {
7265 }
7275 }
7277 /* Issue a warning for the problematic placement of GNU_FIELD present in
7278 either GNAT_COMPONENT_LIST or the discriminants of GNAT_RECORD_TYPE.
7279 IN_VARIANT is true if GNAT_COMPONENT_LIST is the list of a variant.
7280 DO_REORDER is true if fields of GNAT_RECORD_TYPE are being reordered. */
7282 static void
7286 {
7290 Entity_Id gnat_field
7295 = in_variant
7307 = do_reorder
7314 }
7316 /* Likewise but for every field present on GNU_FIELD_LIST. */
7318 static void
7322 {
7326 }
7328 /* Structure holding information for a given variant. */
7330 {
7331 /* The record type of the variant. */
7332 tree type;
7334 /* The name of the variant. */
7335 tree name;
7337 /* The qualifier of the variant. */
7338 tree qual;
7340 /* Whether the variant has a rep clause. */
7343 /* Whether the variant is packed. */
7348 /* Translate and chain GNAT_COMPONENT_LIST present in GNAT_RECORD_TYPE to
7349 GNU_FIELD_LIST, set the result as the field list of GNU_RECORD_TYPE and
7350 finish it up. Return true if GNU_RECORD_TYPE has a rep clause that affects
7351 the layout (see below). When called from gnat_to_gnu_entity during the
7352 processing of a record definition, the GCC node for the parent, if any,
7353 will be the single field of GNU_RECORD_TYPE and the GCC nodes for the
7354 discriminants will be on GNU_FIELD_LIST. The other call to this function
7355 is a recursive call for the component list of a variant and, in this case,
7356 GNU_FIELD_LIST is empty.
7358 PACKED is 1 if this is for a packed record or -1 if this is for a record
7359 with Component_Alignment of Storage_Unit.
7361 DEFINITION is true if we are defining this record type.
7363 CANCEL_ALIGNMENT is true if the alignment should be zeroed before laying
7364 out the record. This means the alignment only serves to force fields to
7365 be bitfields, but not to require the record to be that aligned. This is
7366 used for variants.
7368 ALL_REP is true if a rep clause is present for all the fields.
7370 UNCHECKED_UNION is true if we are building this type for a record with a
7371 Pragma Unchecked_Union.
7373 ARTIFICIAL is true if this is a type that was generated by the compiler.
7375 DEBUG_INFO is true if we need to write debug information about the type.
7377 MAYBE_UNUSED is true if this type may be unused in the end; this doesn't
7378 mean that its contents may be unused as well, only the container itself.
7380 FIRST_FREE_POS, if nonzero, is the first (lowest) free field position in
7381 the outer record type down to this variant level. It is nonzero only if
7382 all the fields down to this level have a rep clause and ALL_REP is false.
7384 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
7385 with a rep clause is to be added; in this case, that is all that should
7386 be done with such fields and the return value will be false. */
7388 static bool
7395 {
7396 const bool needs_xv_encodings
7408 /* For each component referenced in a component declaration create a GCC
7409 field and add it to the list, skipping pragmas in the GNAT list. */
7416 {
7420 /* If present, the _Parent field must have been created as the single
7421 field of the record type. Put it before any other fields. */
7423 {
7426 }
7427 else
7428 {
7432 /* If this is the _Tag field, put it before any other fields. */
7436 /* If this is the _Controller field, put it before the other
7437 fields except for the _Tag or _Parent field. */
7439 {
7442 }
7444 /* If this is a regular field, put it after the other fields. */
7445 else
7446 {
7452 /* And record information for the final layout. */
7457 }
7458 }
7461 }
7463 /* At the end of the component list there may be a variant part. */
7466 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
7467 mutually exclusive and should go in the same memory. To do this we need
7468 to treat each variant as a record whose elements are created from the
7469 component list for the variant. So here we create the records from the
7470 lists for the variants and put them all into the QUAL_UNION_TYPE.
7471 If this is an Unchecked_Union, we make a UNION_TYPE instead or
7472 use GNU_RECORD_TYPE if there are no fields so far. */
7474 {
7478 tree gnu_var_name
7489 gnu_union_name
7492 /* Reuse the enclosing union if this is an Unchecked_Union whose fields
7493 are all in the variant part, to match the layout of C unions. There
7494 is an associated check below. */
7497 else
7498 {
7499 gnu_union_type
7507 }
7509 /* If all the fields down to this level have a rep clause, find out
7510 whether all the fields at this level also have one. If so, then
7511 compute the new first free position to be passed downward. */
7514 {
7516 gnu_field;
7519 {
7522 this_first_free_pos
7524 }
7525 else
7526 {
7529 }
7530 }
7532 /* We build the variants in two passes. The bulk of the work is done in
7533 the first pass, that is to say translating the GNAT nodes, building
7534 the container types and computing the associated properties. However
7535 we cannot finish up the container types during this pass because we
7536 don't know where the variant part will be placed until the end. */
7540 {
7545 vinfo_t vinfo;
7553 /* Set the alignment of the inner type in case we need to make
7554 inner objects into bitfields, but then clear it out so the
7555 record actually gets only the alignment required. */
7561 /* Similarly, if the outer record has a size specified and all
7562 the fields have a rep clause, we can propagate the size. */
7564 {
7568 }
7570 /* Add the fields into the record type for the variant. Note that
7571 we aren't sure to really use it at this point, see below. */
7572 has_rep
7578 all_rep || this_first_free_pos
7581 /* Translate the qualifier and annotate the GNAT node. */
7585 /* Deal with packedness like in gnat_to_gnu_field. */
7587 {
7590 }
7591 else
7592 field_packed
7595 /* Push this variant onto the stack for the second pass. */
7603 /* Compute the global properties that will determine the placement of
7604 the variant part. */
7608 }
7610 /* Round up the first free position to the alignment of the variant part
7611 for the variants without rep clause. This will guarantee a consistent
7612 layout independently of the placement of the variant part. */
7616 /* In the second pass, the container types are adjusted if necessary and
7617 finished up, then the corresponding fields of the variant part are
7618 built with their qualifier, unless this is an unchecked union. */
7620 {
7624 /* If this is an Unchecked_Union whose fields are all in the variant
7625 part and we have a single field with no representation clause or
7626 placed at offset zero, use the field directly to match the layout
7627 of C unions. */
7629 && gnu_field_list
7633 {
7636 }
7637 else
7638 {
7639 /* Finalize the variant type now. We used to throw away empty
7640 record types but we no longer do that because we need them to
7641 generate complete debug info for the variant; otherwise, the
7642 union type definition will be lacking the fields associated
7643 with these empty variants. */
7645 {
7646 /* The variant part will be at offset 0 so we need to ensure
7647 that the fields are laid out starting from the first free
7648 position at this level. */
7650 tree gnu_rep_part;
7654 gnu_rep_part
7656 this_first_free_pos);
7661 }
7668 gnu_field
7670 gnu_union_type,
7671 all_rep_and_size
7680 }
7684 }
7686 /* Only make the QUAL_UNION_TYPE if there are non-empty variants. */
7688 {
7692 {
7696 }
7701 /* If GNU_UNION_TYPE is our record type, it means we must have an
7702 Unchecked_Union with no fields. Verify that and, if so, just
7703 return. */
7705 {
7707 && !gnu_field_list
7710 }
7715 /* Deal with packedness like in gnat_to_gnu_field. */
7718 else
7719 union_field_packed
7722 gnu_variant_part
7724 all_rep_and_size
7730 }
7731 }
7733 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they do,
7734 pull them out and put them onto the appropriate list.
7736 Similarly, pull out the fields with zero size and no rep clause, as they
7737 would otherwise modify the layout and thus very likely run afoul of the
7738 Ada semantics, which are different from those of C here.
7740 Finally, if there is an aliased field placed in the list after fields
7741 with self-referential size, pull out the latter in the same way.
7743 Optionally, if the reordering mechanism is enabled, pull out the fields
7744 with self-referential size, variable size and fixed size not a multiple
7745 of a byte, so that they don't cause the regular fields to be either at
7746 self-referential/variable offset or misaligned. Note, in the latter
7747 case, that this can only happen in packed record types so the alignment
7748 is effectively capped to the byte for the whole record. But we don't
7749 do it for non-packed record types if pragma Optimize_Alignment (Space)
7750 is specified because this can prevent alignment gaps from being filled.
7752 Optionally, if the layout warning is enabled, keep track of the above 4
7753 different kinds of fields and issue a warning if some of them would be
7754 (or are being) reordered by the reordering mechanism.
7756 ??? If we reorder fields, the debugging information will be affected and
7757 the debugger print fields in a different order from the source code. */
7758 const bool do_reorder
7764 const bool w_reorder
7766 && Warn_On_Questionable_Layout
7778 #define MOVE_FROM_FIELD_LIST_TO(LIST) \
7779 do { \
7780 if (gnu_last) \
7781 DECL_CHAIN (gnu_last) = gnu_next; \
7782 else \
7783 gnu_field_list = gnu_next; \
7784 \
7785 DECL_CHAIN (gnu_field) = (LIST); \
7786 (LIST) = gnu_field; \
7787 } while (0)
7791 {
7795 {
7798 }
7801 {
7811 }
7814 {
7817 }
7819 /* We don't need further processing in default mode. */
7821 {
7824 }
7827 {
7829 {
7833 do_reorder);
7834 else
7836 }
7839 {
7842 }
7843 }
7846 {
7848 {
7852 do_reorder);
7853 else
7855 }
7858 {
7861 }
7862 }
7864 else
7865 {
7866 /* If the field has no size, then it cannot be bit-packed. */
7867 const unsigned int bitp_size
7872 /* If the field is bit-packed, we move it to a temporary list that
7873 contains the contiguously preceding bit-packed fields, because
7874 we want to be able to put them back if the misalignment happens
7875 to cancel itself after several bit-packed fields. */
7877 {
7881 {
7884 }
7887 {
7890 }
7891 }
7893 /* No more bit-packed fields, move the existing ones to the end or
7894 put them back at their original location. */
7896 {
7900 {
7902 {
7905 gnat_component_list,
7907 do_reorder);
7908 else
7910 gnat_component_list,
7912 do_reorder);
7913 }
7920 }
7921 else
7922 {
7923 /* Rechain the temporary list in front of GNU_FIELD. */
7926 {
7931 else
7935 }
7936 }
7937 }
7939 else
7941 }
7944 }
7946 #undef MOVE_FROM_FIELD_LIST_TO
7950 /* If permitted, we reorder the fields as follows:
7952 1) all (groups of) fields whose length is fixed and multiple of a byte,
7953 2) the remaining fields whose length is fixed and not multiple of a byte,
7954 3) the remaining fields whose length doesn't depend on discriminants,
7955 4) all fields whose length depends on discriminants,
7956 5) the variant part,
7958 within the record and within each variant recursively. */
7961 {
7962 /* If we have pending bit-packed fields, warn if they would be moved
7963 to after regular fields. */
7967 {
7972 else
7976 }
7977 }
7980 {
7981 /* If we have pending bit-packed fields on the temporary list, we put
7982 them either on the bit-packed list or back on the regular list. */
7984 {
7987 else
7989 }
7991 gnu_field_list
7995 }
7997 /* Otherwise, if there is an aliased field placed after a field whose length
7998 depends on discriminants, we put all the fields of the latter sort, last.
7999 We need to do this in case an object of this record type is mutable. */
8003 /* If P_REP_LIST is nonzero, this means that we are asked to move the fields
8004 in our REP list to the previous level because this level needs them in
8005 order to do a correct layout, i.e. avoid having overlapping fields. */
8009 /* Deal with the annoying case of an extension of a record with variable size
8010 and partial rep clause, for which the _Parent field is forced at offset 0
8011 and has variable size, which we do not support below. Note that we cannot
8012 do it if the field has fixed size because we rely on the presence of the
8013 REP part built below to trigger the reordering of the fields in a derived
8014 record type when all the fields have a fixed position. */
8018 && !variants_have_rep
8019 && first_free_pos
8022 {
8026 }
8028 /* Otherwise, sort the fields by bit position and put them into their own
8029 record, before the others, if we also have fields without rep clause. */
8031 {
8036 /* If all the fields have a rep clause, we can do a flat layout. */
8037 layout_with_rep = !gnu_field_list
8039 gnu_rep_type
8043 gnu_field;
8049 /* Put the fields in the list in order of increasing position, which
8050 means we start from the end. */
8053 {
8057 }
8061 else
8062 {
8067 /* If FIRST_FREE_POS is nonzero, we need to ensure that the fields
8068 without rep clause are laid out starting from this position.
8069 Therefore, we force it as a minimal size on the REP part. */
8070 gnu_rep_part
8073 /* Chain the REP part at the beginning of the field list. */
8076 }
8077 }
8079 /* Chain the variant part at the end of the field list. */
8081 {
8082 /* We make an exception if the variant part is at offset 0, has a fixed
8083 size, and there is a single rep'ed field placed after it because, in
8084 this case, there is an obvious order of increasing position. */
8087 && gnu_rep_list
8091 {
8094 }
8095 else
8097 }
8107 /* Chain the fields with zero size at the beginning of the field list. */
8113 }
8114 \f
8115 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
8116 placed into an Esize, Component_Bit_Offset, or Component_Size value
8117 in the GNAT tree. */
8119 static Uint
8121 {
8123 TCode tcode;
8127 /* See if we've already saved the value for this node. */
8129 {
8137 }
8138 else
8141 /* If we do not return inside this switch, TCODE will be set to the
8142 code to be used in a call to Create_Node. */
8144 {
8146 /* For negative values, build NEGATE_EXPR of the opposite. Such values
8147 can appear for discriminants in expressions for variants. */
8149 {
8153 }
8154 else
8159 /* The only case we handle here is a simple discriminant reference. */
8161 {
8165 /* Climb up the chain of successive extensions, if any. */
8172 {
8173 /* Fall through to common processing as a FIELD_DECL. */
8176 }
8177 else
8179 }
8180 else
8189 CASE_CONVERT:
8193 /* Now just list the operations we handle. */
8223 /* Fold conversions from bytes to bits into inner operations. */
8226 {
8230 {
8233 widest_int op1;
8237 else
8242 }
8243 }
8248 /* For negative values in sizetype, build NEGATE_EXPR of the opposite.
8249 Such values appear in expressions with aligning patterns. Note that,
8250 since sizetype is unsigned, we have to jump through some hoops. */
8252 {
8257 {
8260 }
8261 }
8265 /* In regular mode, inline back only if symbolic annotation is requested
8266 in order to avoid memory explosion on big discriminated record types.
8267 But not in ASIS mode, as symbolic annotation is required for DDA. */
8269 {
8272 }
8273 else
8278 }
8280 /* Now get each of the operands that's relevant for this code. If any
8281 cannot be expressed as a repinfo node, say we can't. */
8284 {
8288 }
8292 /* Save the result in the cache. */
8294 {
8296 /* We can't assume the hash table data hasn't moved since the initial
8297 look up, so we have to search again. Allocating and inserting an
8298 entry at that point would be an alternative, but then we'd better
8299 discard the entry if we decided not to cache it. */
8305 }
8308 }
8310 /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
8311 and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
8312 size and alignment used by Gigi. Prefer SIZE over TYPE_SIZE if non-null.
8313 BY_REF is true if the object is used by reference. */
8315 void
8317 {
8319 {
8322 else
8324 }
8327 {
8336 }
8341 }
8343 /* Return first element of field list whose TREE_PURPOSE is the same as ELEM.
8344 Return NULL_TREE if there is no such element in the list. */
8346 static tree
8348 {
8350 {
8355 }
8357 }
8359 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding GCC type,
8360 set Component_Bit_Offset and Esize of the components to the position and
8361 size used by Gigi. */
8363 static void
8365 {
8366 /* For an extension, the inherited components have not been translated because
8367 they are fetched from the _Parent component on the fly. */
8368 const bool is_extension
8371 /* We operate by first making a list of all fields and their position (we
8372 can get the size easily) and then update all the sizes in the tree. */
8373 tree gnu_list
8384 {
8386 gnu_list);
8388 {
8392 /* If we are just annotating types and the type is tagged, the tag
8393 and the parent components are not generated by the front-end so
8394 we need to add the appropriate offset to each component without
8395 representation clause. */
8399 {
8400 tree parent_bit_offset;
8402 /* For a component appearing in the current extension, the
8403 offset is the size of the parent. */
8406 parent_bit_offset
8408 bitsizetype);
8409 else
8413 parent_bit_offset
8417 offset
8421 parent_bit_offset,
8422 bitsize_unit_node)));
8423 }
8425 /* If the field has a variable offset, also compute the normalized
8426 position since it's easier to do on trees here than to deduce
8427 it from the annotated expression of Component_Bit_Offset. */
8429 {
8435 }
8437 Set_Component_Bit_Offset
8443 }
8445 {
8446 /* If there is no entry, this is an inherited component whose
8447 position is the same as in the parent type. */
8450 /* If we are just annotating types, discriminants renaming those of
8451 the parent have no entry so deal with them specifically. */
8458 {
8463 }
8469 }
8470 }
8471 }
8472 \f
8473 /* Scan all fields in GNU_TYPE and return a TREE_LIST where TREE_PURPOSE is
8474 the FIELD_DECL and TREE_VALUE a TREE_VEC containing the byte position, the
8475 value to be placed into DECL_OFFSET_ALIGN and the bit position. The list
8476 of fields is flattened, except for variant parts if DO_NOT_FLATTEN_VARIANT
8477 is set to true. GNU_POS is to be added to the position, GNU_BITPOS to the
8478 bit position, OFFSET_ALIGN is the present offset alignment. GNU_LIST is a
8479 pre-existing list to be chained to the newly created entries. */
8481 static tree
8484 {
8485 tree gnu_field;
8488 gnu_field;
8490 {
8495 unsigned int our_offset_align
8504 /* Recurse on internal fields, flattening the nested fields except for
8505 those in the variant part, if requested. */
8507 {
8511 gnu_list
8515 else
8516 gnu_list
8520 }
8521 }
8524 }
8526 /* Return a list describing the substitutions needed to reflect the
8527 discriminant substitutions from GNAT_TYPE to GNAT_SUBTYPE. They can
8528 be in any order. The values in an element of the list are in the form
8529 of operands to SUBSTITUTE_IN_EXPR. DEFINITION is true if this is for
8530 a definition of GNAT_SUBTYPE. */
8534 {
8536 Entity_Id gnat_discrim;
8537 Node_Id gnat_constr;
8544 /* Ignore access discriminants. */
8546 {
8549 elaborate_expression
8555 }
8558 }
8560 /* Scan all fields in QUAL_UNION_TYPE and return a list describing the
8561 variants of QUAL_UNION_TYPE that are still relevant after applying
8562 the substitutions described in SUBST_LIST. GNU_LIST is a pre-existing
8563 list to be prepended to the newly created entries. */
8568 {
8569 tree gnu_field;
8572 gnu_field;
8574 {
8582 /* If the new qualifier is not unconditionally false, its variant may
8583 still be accessed. */
8585 {
8587 variant_desc v
8592 /* Recurse on the variant subpart of the variant, if any. */
8598 /* If the new qualifier is unconditionally true, the subsequent
8599 variants cannot be accessed. */
8602 }
8603 }
8606 }
8607 \f
8608 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
8609 corresponding to GNAT_OBJECT. If the size is valid, return an INTEGER_CST
8610 corresponding to its value. Otherwise, return NULL_TREE. KIND is set to
8611 VAR_DECL if we are specifying the size of an object, TYPE_DECL for the
8612 size of a type, and FIELD_DECL for the size of a field. COMPONENT_P is
8613 true if we are being called to process the Component_Size of GNAT_OBJECT;
8614 this is used only for error messages. ZERO_OK is true if a size of zero
8615 is permitted; if ZERO_OK is false, it means that a size of zero should be
8616 treated as an unspecified size. */
8618 static tree
8621 {
8622 Node_Id gnat_error_node;
8625 /* Return 0 if no size was specified. */
8629 /* Ignore a negative size since that corresponds to our back-annotation. */
8633 /* Find the node to use for error messages. */
8640 else
8643 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
8644 but cannot be represented in bitsizetype. */
8647 {
8650 gnat_object);
8651 else
8653 gnat_object);
8655 }
8657 /* Ignore a zero size if it is not permitted. */
8661 /* The size of objects is always a multiple of a byte. */
8664 {
8668 else
8672 }
8674 /* If this is an integral type or a packed array type, the front-end has
8675 already verified the size, so we need not do it here (which would mean
8676 checking against the bounds). However, if this is an aliased object,
8677 it may not be smaller than the type of the object. */
8682 /* If the object is a record that contains a template, add the size of the
8683 template to the specified size. */
8689 /* If a type needs strict alignment, a component of this type in
8690 a packed record cannot be packed and thus uses the type size. */
8693 else
8696 /* Modify the size of a discriminated type to be the maximum size. */
8700 /* If this is an access type or a fat pointer, the minimum size is that given
8701 by the smallest integral mode that's valid for pointers. */
8703 {
8708 }
8710 /* Issue an error either if the default size of the object isn't a constant
8711 or if the new size is smaller than it. */
8715 {
8717 post_error_ne_tree
8720 else
8721 post_error_ne_tree
8725 }
8728 }
8729 \f
8730 /* Similarly, but both validate and process a value of RM size. This routine
8731 is only called for types. */
8733 static void
8735 {
8736 Node_Id gnat_attr_node;
8739 /* Do nothing if no size was specified. */
8743 /* Ignore a negative size since that corresponds to our back-annotation. */
8747 /* Only issue an error if a Value_Size clause was explicitly given.
8748 Otherwise, we'd be duplicating an error on the Size clause. */
8749 gnat_attr_node
8752 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
8753 but cannot be represented in bitsizetype. */
8756 {
8759 gnat_entity);
8761 }
8763 /* Ignore a zero size unless a Value_Size clause exists, or a size clause
8764 exists, or this is an integer type, in which case the front-end will
8765 have always set it. */
8774 /* If the old size is self-referential, get the maximum size. */
8778 /* Issue an error either if the old size of the object isn't a constant or
8779 if the new size is smaller than it. The front-end has already verified
8780 this for scalar and packed array types. */
8788 && TYPE_PACKED_ARRAY_TYPE_P
8791 {
8793 post_error_ne_tree
8797 }
8799 /* Otherwise, set the RM size proper for integral types... */
8806 /* ...or the Ada size for record and union types. */
8810 }
8811 \f
8812 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
8813 a type or object whose present alignment is ALIGN. If this alignment is
8814 valid, return it. Otherwise, give an error and return ALIGN. */
8816 static unsigned int
8818 {
8821 Node_Id gnat_error_node;
8823 /* Don't worry about checking alignment if alignment was not specified
8824 by the source program and we already posted an error for this entity. */
8828 /* Post the error on the alignment clause if any. Note, for the implicit
8829 base type of an array type, the alignment clause is on the first
8830 subtype. */
8838 gnat_error_node =
8841 else
8844 /* Within GCC, an alignment is an integer, so we must make sure a value is
8845 specified that fits in that range. Also, there is an upper bound to
8846 alignments we can support/allow. */
8854 {
8858 /* If the default alignment of "double" or larger scalar types is
8859 specifically capped and the new alignment is above the cap, do
8860 not post an error and change the alignment only if there is an
8861 alignment clause; this makes it possible to have the associated
8862 GCC type overaligned by default for performance reasons. */
8864 {
8865 Entity_Id gnat_type
8867 is_capped_double
8869 }
8871 {
8872 Entity_Id gnat_type
8874 is_capped_double
8876 }
8877 else
8881 {
8884 }
8885 else
8886 {
8893 }
8894 }
8895 else
8896 {
8900 }
8903 }
8904 \f
8905 /* Promote the alignment of GNU_TYPE corresponding to GNAT_ENTITY. Return
8906 a positive value on success or zero on failure. */
8908 static unsigned int
8910 {
8913 /* No point in promoting the alignment if this doesn't prevent BLKmode access
8914 to the object, in particular block copy, as this will for example disable
8915 the NRV optimization for it. No point in jumping through all the hoops
8916 needed in order to support BIGGEST_ALIGNMENT if we don't really have to.
8917 So we cap to the smallest alignment that corresponds to a known efficient
8918 memory access pattern, except for Atomic and Volatile_Full_Access. */
8920 {
8923 }
8924 else
8925 {
8928 }
8930 /* Do the promotion within the above limits. */
8936 else
8939 /* But make sure not to under-align the object. */
8943 /* And honor the minimum valid atomic alignment, if any. */
8944 #ifdef MINIMUM_ATOMIC_ALIGNMENT
8947 #endif
8950 }
8951 \f
8952 /* Verify that TYPE is something we can implement atomically. If not, issue
8953 an error for GNAT_ENTITY. COMPONENT_P is true if we are being called to
8954 process a component type. */
8956 static void
8958 {
8960 Node_Id gnat_node;
8961 machine_mode mode;
8964 tree size;
8966 /* If this is an anonymous base type, nothing to check, the error will be
8967 reported on the source type if need be. */
8976 /* Consider all aligned floating-point types atomic and any aligned types
8977 that are represented by integers no wider than a machine word. */
8978 scalar_int_mode int_mode;
8985 /* For the moment, also allow anything that has an alignment equal to its
8986 size and which is smaller than a word. */
8997 {
8998 unsigned char pragma_id
9003 {
9006 }
9007 }
9015 else
9018 }
9019 \f
9021 /* Helper for the intrin compatibility checks family. Evaluate whether
9022 two types are definitely incompatible. */
9024 static bool
9026 {
9041 {
9048 /* Assume designated types are ok. We'd need to account for char * and
9049 void * variants to do better, which could rapidly get messy and isn't
9050 clearly worth the effort. */
9055 }
9058 }
9060 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
9061 on the Ada/builtin argument lists for the INB binding. */
9063 static bool
9065 {
9071 /* Sequence position of the last argument we checked. */
9075 {
9079 /* If we've exhausted both lists simultaneously, we're done. */
9083 /* If one list is shorter than the other, they fail to match. */
9087 /* If we're done with the Ada args and not with the internal builtin
9088 args, or the other way around, complain. */
9091 {
9094 }
9098 {
9102 }
9104 /* Otherwise, check that types match for the current argument. */
9105 argpos ++;
9107 {
9111 }
9116 }
9119 }
9121 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
9122 on the Ada/builtin return values for the INB binding. */
9124 static bool
9126 {
9130 /* Accept function imported as procedure, common and convenient. */
9135 /* Check return types compatibility otherwise. Note that this
9136 handles void/void as well. */
9138 {
9142 }
9145 }
9147 /* Check and return whether the Ada and gcc builtin profiles bound by INB are
9148 compatible. Issue relevant warnings when they are not.
9150 This is intended as a light check to diagnose the most obvious cases, not
9151 as a full fledged type compatibility predicate. It is the programmer's
9152 responsibility to ensure correctness of the Ada declarations in Imports,
9153 especially when binding straight to a compiler internal. */
9155 static bool
9157 {
9158 /* Check compatibility on return values and argument lists, each responsible
9159 for posting warnings as appropriate. Ensure use of the proper sloc for
9160 this purpose. */
9173 }
9174 \f
9175 /* Return a FIELD_DECL node modeled on OLD_FIELD. FIELD_TYPE is its type
9176 and RECORD_TYPE is the type of the parent. If SIZE is nonzero, it is the
9177 specified size for this field. POS_LIST is a position list describing
9178 the layout of OLD_FIELD and SUBST_LIST a substitution list to be applied
9179 to this layout. */
9181 static tree
9185 {
9197 /* If the position is now a constant, we can set it as the position of the
9198 field when we make it. Otherwise, we need to deal with it specially. */
9201 else
9204 new_field
9210 {
9212 /* Finalize the position. */
9221 }
9229 }
9231 /* Create the REP part of RECORD_TYPE with REP_TYPE. If MIN_SIZE is nonzero,
9232 it is the minimal size the REP_PART must have. */
9234 static tree
9236 {
9237 tree field;
9247 }
9249 /* Return the REP part of RECORD_TYPE, if any. Otherwise return NULL. */
9251 static tree
9253 {
9256 /* The REP part is the first field, internal, another record, and its name
9257 starts with an 'R'. */
9265 }
9267 /* Return the variant part of RECORD_TYPE, if any. Otherwise return NULL. */
9269 tree
9271 {
9272 tree field;
9274 /* The variant part is the only internal field that is a qualified union. */
9281 }
9283 /* Return a new variant part modeled on OLD_VARIANT_PART. VARIANT_LIST is
9284 the list of variants to be used and RECORD_TYPE is the type of the parent.
9285 POS_LIST is a position list describing the layout of fields present in
9286 OLD_VARIANT_PART and SUBST_LIST a substitution list to be applied to this
9287 layout. DEBUG_INFO_P is true if we need to write debug information. */
9289 static tree
9295 {
9303 /* First create the type of the variant part from that of the old one. */
9309 /* If the position of the variant part is constant, subtract it from the
9310 size of the type of the parent to get the new size. This manual CSE
9311 reduces the code size when not optimizing. */
9315 {
9325 first_bit));
9328 }
9329 else
9332 /* Now finish up the new variants and populate the union type. */
9334 {
9338 /* Skip variants that don't belong to this nesting level. */
9342 /* Retrieve the list of fields already added to the new variant. */
9346 /* If the old variant had a variant subpart, we need to create a new
9347 variant subpart and add it to the field list. */
9351 {
9352 tree new_variant_subpart
9355 debug_info_p);
9358 }
9360 /* Finish up the new variant and create the field. */
9365 new_field
9373 }
9375 /* Finish up the union type and create the variant part. Note that we don't
9376 reverse the field list because VARIANT_LIST has been traversed in reverse
9377 order. */
9382 new_variant_part
9388 /* With multiple discriminants it is possible for an inner variant to be
9389 statically selected while outer ones are not; in this case, the list
9390 of fields of the inner variant is not flattened and we end up with a
9391 qualified union with a single member. Drop the useless container. */
9393 {
9402 }
9405 }
9407 /* Copy the size (and alignment and alias set) from OLD_TYPE to NEW_TYPE,
9408 which are both RECORD_TYPE, after applying the substitutions described
9409 in SUBST_LIST. */
9411 static void
9414 {
9438 SET_TYPE_ADA_SIZE
9442 /* Finalize the size. */
9445 }
9447 /* Return true if DISC is a stored discriminant of RECORD_TYPE. */
9451 {
9458 else
9460 }
9462 /* Copy the layout from {GNAT,GNU}_OLD_TYPE to {GNAT,GNU}_NEW_TYPE, which are
9463 both record types, after applying the substitutions described in SUBST_LIST.
9464 DEBUG_INFO_P is true if we need to write debug information for NEW_TYPE. */
9466 static void
9468 Entity_Id gnat_old_type,
9469 tree gnu_new_type,
9470 tree gnu_old_type,
9473 {
9480 /* Look for REP and variant parts in the old type. */
9484 /* If there is a variant part, we must compute whether the constraints
9485 statically select a particular variant. If so, we simply drop the
9486 qualified union and flatten the list of fields. Otherwise we will
9487 build a new qualified union for the variants that are still relevant. */
9489 {
9496 /* If all the qualifiers are unconditionally true, the innermost variant
9497 is statically selected. */
9501 {
9504 }
9506 /* Otherwise, create the new variants. */
9509 {
9512 tree suffix
9521 gnu_subst_list);
9523 }
9524 }
9525 else
9526 {
9529 }
9531 /* Make a list of fields and their position in the old type. */
9532 tree gnu_pos_list
9538 /* Now go down every component in the new type and compute its size and
9539 position from those of the component in the old type and the stored
9540 constraints of the new type. */
9553 {
9563 /* If the type is the same, retrieve the GCC type from the
9564 old field to take into account possible adjustments. */
9567 else
9570 /* If there was a component clause, the field types must be the same
9571 for the old and new types, so copy the data from the old field to
9572 avoid recomputation here. Also if the field is justified modular
9573 and the optimization in gnat_to_gnu_field was applied. */
9579 {
9582 }
9584 /* If the old field was packed and of constant size, we have to get the
9585 old size here as it might differ from what the Etype conveys and the
9586 latter might overlap with the following field. Try to arrange the
9587 type for possible better packing along the way. */
9590 {
9596 }
9598 else
9601 /* If the context of the old field is the old type or its REP part,
9602 put the field directly in the new type; otherwise look up the
9603 context in the variant list and put the field either in the new
9604 type if there is a selected variant or in one new variant. */
9608 else
9609 {
9611 tree rep_part;
9621 else
9622 /* The front-end may pass us zombie components if it fails to
9623 recognize that a constrain statically selects a particular
9624 variant. Discard them. */
9626 }
9628 /* Now create the new field modeled on the old one. */
9629 gnu_field
9635 /* If the context is a variant, put it in the new variant directly. */
9637 {
9639 {
9642 }
9643 else
9644 {
9647 }
9648 }
9650 /* To match the layout crafted in components_to_record, if this is
9651 the _Tag or _Parent field, put it before any other fields. */
9655 /* Similarly, if this is the _Controller field, put it before the
9656 other fields except for the _Tag or _Parent field. */
9658 {
9661 }
9663 /* Otherwise, put it after the other fields. */
9664 else
9665 {
9667 {
9672 }
9673 else
9674 {
9677 }
9678 }
9680 /* For a stored discriminant in a derived type, replace the field. */
9682 {
9685 }
9686 else
9688 }
9690 /* Put the fields with fixed position in order of increasing position. */
9694 /* Put the fields with variable position at the end. */
9698 /* If there is a variant list and no selected variant, we need to create the
9699 nest of variant parts from the old nest. */
9701 {
9705 /* Same processing as above for the fields of each variant. */
9707 {
9714 }
9716 tree new_variant_part
9722 }
9727 /* If NEW_TYPE is a subtype, it inherits all the attributes from OLD_TYPE.
9728 Otherwise sizes and alignment must be computed independently. */
9732 /* Now go through the entities again looking for Itypes that we have not yet
9733 elaborated (e.g. Etypes of fields that have Original_Components). */
9742 }
9744 /* Associate to GNU_TYPE, the translation of GNAT_ENTITY, which is
9745 the implementation type of a packed array type (Is_Packed_Array_Impl_Type),
9746 the original array type if it has been translated. This association is a
9747 parallel type for GNAT encodings or a debug type for standard DWARF. Note
9748 that for standard DWARF, we also want to get the original type name. */
9750 static void
9752 {
9753 Entity_Id gnat_original_array_type
9755 tree gnu_original_array_type;
9766 {
9774 }
9775 else
9777 }
9778 \f
9779 /* Given a type T, a FIELD_DECL F, and a replacement value R, return an
9780 equivalent type with adjusted size expressions where all occurrences
9781 of references to F in a PLACEHOLDER_EXPR have been replaced by R.
9783 The function doesn't update the layout of the type, i.e. it assumes
9784 that the substitution is purely formal. That's why the replacement
9785 value R must itself contain a PLACEHOLDER_EXPR. */
9787 tree
9789 {
9790 tree nt;
9795 {
9801 /* First the domain types of arrays. */
9804 {
9816 SET_TYPE_INDEX_TYPE
9820 }
9822 /* Then the subtypes. */
9825 {
9837 }
9849 /* These should never show up here. */
9853 {
9873 }
9878 {
9880 tree field;
9882 /* Start out with no fields, make new fields, and chain them
9883 in. If we haven't actually changed the type of any field,
9884 discard everything we've done and return the old type. */
9889 {
9894 {
9897 }
9901 {
9904 }
9906 /* Do the substitution inside the qualifier, if any. */
9908 {
9911 {
9914 }
9915 }
9922 }
9932 }
9936 }
9937 }
9938 \f
9939 /* Return the RM size of GNU_TYPE. This is the actual number of bits
9940 needed to represent the object. */
9942 tree
9944 {
9945 /* For integral types, we store the RM size explicitly. */
9949 /* Return the RM size of the actual data plus the size of the template. */
9952 return
9957 /* For record or union types, we store the size explicitly. */
9963 /* For other types, this is just the size. */
9965 }
9966 \f
9967 /* Return the name to be used for GNAT_ENTITY. If a type, create a
9968 fully-qualified name, possibly with type information encoding.
9969 Otherwise, return the name. */
9973 {
9976 }
9978 tree
9980 {
9983 }
9985 /* Return an identifier representing the external name to be used for
9986 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
9987 and the specified suffix. */
9989 tree
9991 {
9999 /* A variable using the Stdcall convention lives in a DLL. We adjust
10000 its name to use the jump table, the _imp__NAME contains the address
10001 for the NAME variable. */
10004 {
10010 }
10013 }
10015 /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
10016 string, return a new IDENTIFIER_NODE that is the concatenation of
10017 the name followed by "___" and the specified suffix. */
10019 tree
10021 {
10028 }
10030 /* Initialize data structures of the decl.c module. */
10032 void
10034 {
10035 /* Initialize the cache of annotated values. */
10038 /* Initialize the association of dummy types with subprograms. */
10040 }
10042 /* Destroy data structures of the decl.c module. */
10044 void
10046 {
10047 /* Destroy the cache of annotated values. */
10051 /* Destroy the association of dummy types with subprograms. */
10054 }