| blob | d908a1b750d7357228c8433a6f2ce8839b6db779 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2015, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License along with GCC; see the file COPYING3. If not see *
19 * <http://www.gnu.org/licenses/>. *
20 * *
21 * GNAT was originally developed by the GNAT team at New York University. *
22 * Extensive contributions were provided by Ada Core Technologies Inc. *
23 * *
24 ****************************************************************************/
66 /* "stdcall" and "thiscall" conventions should be processed in a specific way
67 on 32-bit x86/Windows only. The macros below are helpers to avoid having
68 to check for a Windows specific attribute throughout this unit. */
70 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
71 #ifdef TARGET_64BIT
72 #define Has_Stdcall_Convention(E) \
73 (!TARGET_64BIT && Convention (E) == Convention_Stdcall)
74 #define Has_Thiscall_Convention(E) \
75 (!TARGET_64BIT && is_cplusplus_method (E))
76 #else
77 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
78 #define Has_Thiscall_Convention(E) (is_cplusplus_method (E))
79 #endif
80 #else
81 #define Has_Stdcall_Convention(E) 0
82 #define Has_Thiscall_Convention(E) 0
83 #endif
87 /* Stack realignment is necessary for functions with foreign conventions when
88 the ABI doesn't mandate as much as what the compiler assumes - that is, up
89 to PREFERRED_STACK_BOUNDARY.
91 Such realignment can be requested with a dedicated function type attribute
92 on the targets that support it. We define FOREIGN_FORCE_REALIGN_STACK to
93 characterize the situations where the attribute should be set. We rely on
94 compiler configuration settings for 'main' to decide. */
96 #ifdef MAIN_STACK_BOUNDARY
97 #define FOREIGN_FORCE_REALIGN_STACK \
98 (MAIN_STACK_BOUNDARY < PREFERRED_STACK_BOUNDARY)
99 #else
100 #define FOREIGN_FORCE_REALIGN_STACK 0
101 #endif
103 struct incomplete
104 {
106 tree old_type;
107 Entity_Id full_type;
108 };
110 /* These variables are used to defer recursively expanding incomplete types
111 while we are processing an array, a record or a subprogram type. */
115 /* This variable is used to delay expanding From_Limited_With types until the
116 end of the spec. */
120 tree discriminant;
121 tree replacement;
126 /* The type of the variant. */
127 tree type;
129 /* The associated field. */
130 tree field;
132 /* The value of the qualifier. */
133 tree qual;
135 /* The type of the variant after transformation. */
136 tree new_type;
140 /* A hash table used to cache the result of annotate_value. */
143 {
146 {
148 }
152 {
154 }
156 static void
158 {
164 else
166 }
167 };
215 /* The relevant constituents of a subprogram binding to a GCC builtin. Used
216 to pass around calls performing profile compatibility checks. */
225 \f
226 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
227 entity, return the equivalent GCC tree for that entity (a ..._DECL node)
228 and associate the ..._DECL node with the input GNAT defining identifier.
230 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
231 initial value (in GCC tree form). This is optional for a variable. For
232 a renamed entity, GNU_EXPR gives the object being renamed.
234 DEFINITION is nonzero if this call is intended for a definition. This is
235 used for separate compilation where it is necessary to know whether an
236 external declaration or a definition must be created if the GCC equivalent
237 was not created previously. The value of 1 is normally used for a nonzero
238 DEFINITION, but a value of 2 is used in special circumstances, defined in
239 the code. */
241 tree
243 {
244 /* Contains the kind of the input GNAT node. */
246 /* True if this is a type. */
248 /* True if debug info is requested for this entity. */
250 /* True if this entity is to be considered as imported. */
251 const bool imported_p
253 /* For a type, contains the equivalent GNAT node to be used in gigi. */
255 /* Temporary used to walk the GNAT tree. */
256 Entity_Id gnat_temp;
257 /* Contains the GCC DECL node which is equivalent to the input GNAT node.
258 This node will be associated with the GNAT node by calling at the end
259 of the `switch' statement. */
261 /* Contains the GCC type to be used for the GCC node. */
263 /* Contains the GCC size tree to be used for the GCC node. */
265 /* Contains the GCC name to be used for the GCC node. */
266 tree gnu_entity_name;
267 /* True if we have already saved gnu_decl as a GNAT association. */
269 /* True if we incremented defer_incomplete_level. */
271 /* True if we incremented force_global. */
273 /* True if we should check to see if elaborated during processing. */
275 /* True if we made GNU_DECL and its type here. */
277 /* Size and alignment of the GCC node, if meaningful. */
279 /* Contains the list of attributes directly attached to the entity. */
282 /* Since a use of an Itype is a definition, process it as such if it
283 is not in a with'ed unit. */
285 && is_type
289 {
290 /* Ensure that we are in a subprogram mentioned in the Scope chain of
291 this entity, our current scope is global, or we encountered a task
292 or entry (where we can't currently accurately check scoping). */
295 {
298 }
303 {
308 gnat_temp
320 && (current_function_decl
322 {
325 }
326 }
328 /* This abort means the Itype has an incorrect scope, i.e. that its
329 scope does not correspond to the subprogram it is declared in. */
331 }
333 /* If we've already processed this entity, return what we got last time.
334 If we are defining the node, we should not have already processed it.
335 In that case, we will abort below when we try to save a new GCC tree
336 for this object. We also need to handle the case of getting a dummy
337 type when a Full_View exists but be careful so as not to trigger its
338 premature elaboration. */
341 {
350 {
351 gnu_decl
355 }
358 }
360 /* If this is a numeric or enumeral type, or an access type, a nonzero Esize
361 must be specified unless it was specified by the programmer. Exceptions
362 are for access-to-protected-subprogram types and all access subtypes, as
363 another GNAT type is used to lay out the GCC type for them. */
374 /* The RM size must be specified for all discrete and fixed-point types. */
378 /* If we get here, it means we have not yet done anything with this entity.
379 If we are not defining it, it must be a type or an entity that is defined
380 elsewhere or externally, otherwise we should have defined it already. */
382 || type_annotate_only
383 || is_type
390 /* Get the name of the entity and set up the line number and filename of
391 the original definition for use in any decl we make. Make sure we do not
392 inherit another source location. */
398 /* For cases when we are not defining (i.e., we are referencing from
399 another compilation unit) public entities, show we are at global level
400 for the purpose of computing scopes. Don't do this for components or
401 discriminants since the relevant test is whether or not the record is
402 being defined. */
410 /* Handle any attributes directly attached to the entity. */
414 /* Do some common processing for types. */
416 {
417 /* Compute the equivalent type to be used in gigi. */
420 /* Machine_Attributes on types are expected to be propagated to
421 subtypes. The corresponding Gigi_Rep_Items are only attached
422 to the first subtype though, so we handle the propagation here. */
429 /* Compute a default value for the size of an elementary type. */
431 {
441 else
446 }
447 }
450 {
452 /* If this is a use of a deferred constant without address clause,
453 get its full definition. */
457 {
458 gnu_decl
462 }
464 /* If we have an external constant that we are not defining, get the
465 expression that is was defined to represent. We may throw it away
466 later if it is not a constant. But do not retrieve the expression
467 if it is an allocator because the designated type might be dummy
468 at this point. */
474 {
478 /* The expression may contain N_Expression_With_Actions nodes and
479 thus object declarations from other units. In this case, even
480 though the expression will eventually be discarded since not a
481 constant, the declarations would be stuck either in the global
482 varpool or in the current scope. Therefore we force the local
483 context and create a fake scope that we'll zap at the end. */
485 {
488 }
498 }
500 /* Ignore deferred constant definitions without address clause since
501 they are processed fully in the front-end. If No_Initialization
502 is set, this is not a deferred constant but a constant whose value
503 is built manually. And constants that are renamings are handled
504 like variables. */
506 && !gnu_expr
510 {
514 }
516 /* Ignore constant definitions already marked with the error node. See
517 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
519 && gnu_expr
522 {
525 }
534 {
535 /* The GNAT record where the component was defined. */
538 /* If the entity is a discriminant of an extended tagged type used to
539 rename a discriminant of the parent type, return the latter. */
542 {
543 gnu_decl
548 }
550 /* If the entity is an inherited component (in the case of extended
551 tagged record types), just return the original entity, which must
552 be a FIELD_DECL. Likewise for discriminants. If the entity is a
553 non-girder discriminant (in the case of derived untagged record
554 types), return the stored discriminant it renames. */
557 {
558 gnu_decl
563 }
565 /* Otherwise, if we are not defining this and we have no GCC type
566 for the containing record, make one for it. Then we should
567 have made our own equivalent. */
569 {
570 /* ??? If this is in a record whose scope is a protected
571 type and we have an Original_Record_Component, use it.
572 This is a workaround for major problems in protected type
573 handling. */
577 {
578 gnu_decl
584 }
590 }
592 else
593 /* Here we have no GCC type and this is a reference rather than a
594 definition. This should never happen. Most likely the cause is
595 reference before declaration in the GNAT tree for gnat_entity. */
597 }
603 /* Simple variables, loop variables, Out parameters and exceptions. */
604 object:
605 {
606 /* Always create a variable for volatile objects and variables seen
607 constant but with a Linker_Section pragma. */
608 bool const_flag
625 tree gnu_object_size;
628 {
632 else
634 }
636 /* Get the type after elaborating the renamed object. */
639 /* If this is a standard exception definition, then use the standard
640 exception type. This is necessary to make sure that imported and
641 exported views of exceptions are properly merged in LTO mode. */
646 /* For a debug renaming declaration, build a debug-only entity. */
648 {
649 /* Force a non-null value to make sure the symbol is retained. */
653 integer_minus_one_node));
660 }
662 /* If this is a loop variable, its type should be the base type.
663 This is because the code for processing a loop determines whether
664 a normal loop end test can be done by comparing the bounds of the
665 loop against those of the base type, which is presumed to be the
666 size used for computation. But this is not correct when the size
667 of the subtype is smaller than the type. */
671 /* Reject non-renamed objects whose type is an unconstrained array or
672 any object whose type is a dummy type or void. */
677 {
680 force_global--;
682 }
684 /* If an alignment is specified, use it if valid. Note that exceptions
685 are objects but don't have an alignment. We must do this before we
686 validate the size, since the alignment can affect the size. */
688 {
694 /* No point in changing the type if there is an address clause
695 as the final type of the object will be a reference type. */
698 else
699 {
702 gnu_type
706 /* If a padding record was made, declare it now since it will
707 never be declared otherwise. This is necessary to ensure
708 that its subtrees are properly marked. */
712 }
713 }
715 /* If we are defining the object, see if it has a Size and validate it
716 if so. If we are not defining the object and a Size clause applies,
717 simply retrieve the value. We don't want to ignore the clause and
718 it is expected to have been validated already. Then get the new
719 type, if any. */
728 {
729 gnu_type
735 }
737 /* If this object has self-referential size, it must be a record with
738 a default discriminant. We are supposed to allocate an object of
739 the maximum size in this case, unless it is a constant with an
740 initializing expression, in which case we can get the size from
741 that. Note that the resulting size may still be a variable, so
742 this may end up with an indirect allocation. */
745 {
747 {
750 {
751 /* If the initializing expression is itself a constant,
752 despite having a nominal type with self-referential
753 size, we can get the size directly from it. */
755 && TYPE_IS_PADDING_P
759 || DECL_READONLY_ONCE_ELAB
762 else
763 gnu_size
765 }
766 else
768 }
769 /* We may have no GNU_EXPR because No_Initialization is
770 set even though there's an Expression. */
775 gnu_size
777 (Etype
779 else
780 {
783 }
785 /* If we are at global level and the size isn't constant, call
786 elaborate_expression_1 to make a variable for it rather than
787 calculating it each time. */
792 }
794 /* If the size is zero byte, make it one byte since some linkers have
795 troubles with zero-sized objects. If the object will have a
796 template, that will make it nonzero so don't bother. Also avoid
797 doing that for an object renaming or an object with an address
798 clause, as we would lose useful information on the view size
799 (e.g. for null array slices) and we are not allocating the object
800 here anyway. */
812 /* If this is an object with no specified size and alignment, and
813 if either it is atomic or we are not optimizing alignment for
814 space and it is composite and not an exception, an Out parameter
815 or a reference to another object, and the size of its type is a
816 constant, set the alignment to the smallest one which is not
817 smaller than the size, with an appropriate cap. */
826 && !imported_p
830 {
833 /* No point in promoting the alignment if this doesn't prevent
834 BLKmode access to the object, in particular block copy, as
835 this will for example disable the NRV optimization for it.
836 No point in jumping through all the hoops needed in order
837 to support BIGGEST_ALIGNMENT if we don't really have to.
838 So we cap to the smallest alignment that corresponds to
839 a known efficient memory access pattern of the target. */
841 {
844 }
845 else
846 {
849 }
856 else
859 /* But make sure not to under-align the object. */
863 /* And honor the minimum valid atomic alignment, if any. */
864 #ifdef MINIMUM_ATOMIC_ALIGNMENT
867 #endif
868 }
870 /* If the object is set to have atomic components, find the component
871 type and validate it.
873 ??? Note that we ignore Has_Volatile_Components on objects; it's
874 not at all clear what to do in that case. */
876 {
885 }
887 /* Now check if the type of the object allows atomic access. Note
888 that we must test the type, even if this object has size and
889 alignment to allow such access, because we will be going inside
890 the padded record to assign to the object. We could fix this by
891 always copying via an intermediate value, but it's not clear it's
892 worth the effort. */
896 /* If this is an aliased object with an unconstrained nominal subtype,
897 make a type that includes the template. */
901 {
902 tree gnu_array
904 gnu_type
906 gnu_type,
909 debug_info_p);
910 }
912 /* ??? If this is an object of CW type initialized to a value, try to
913 ensure that the object is sufficient aligned for this value, but
914 without pessimizing the allocation. This is a kludge necessary
915 because we don't support dynamic alignment. */
922 #ifdef MINIMUM_ATOMIC_ALIGNMENT
923 /* If the size is a constant and no alignment is specified, force
924 the alignment to be the minimum valid atomic alignment. The
925 restriction on constant size avoids problems with variable-size
926 temporaries; if the size is variable, there's no issue with
927 atomic access. Also don't do this for a constant, since it isn't
928 necessary and can interfere with constant replacement. Finally,
929 do not do it for Out parameters since that creates an
930 size inconsistency with In parameters. */
940 #endif
942 /* Make a new type with the desired size and alignment, if needed.
943 But do not take into account alignment promotions to compute the
944 size of the object. */
947 {
953 /* If a padding record was made, declare it now since it will
954 never be declared otherwise. This is necessary to ensure
955 that its subtrees are properly marked. */
959 }
961 /* If this is a renaming, avoid as much as possible to create a new
962 object. However, in several cases, creating it is required.
963 This processing needs to be applied to the raw expression so
964 as to make it more likely to rename the underlying object. */
966 {
969 /* If the renamed object had padding, strip off the reference
970 to the inner object and reset our type. */
973 /* Strip useless conversions around the object. */
975 {
978 }
980 /* Or else, if the renamed object has an unconstrained type with
981 default discriminant, use the padded type. */
984 == gnu_type
988 /* Case 1: If this is a constant renaming stemming from a function
989 call, treat it as a normal object whose initial value is what is
990 being renamed. RM 3.3 says that the result of evaluating a
991 function call is a constant object. Treat constant literals
992 the same way. As a consequence, it can be the inner object of
993 a constant renaming. In this case, the renaming must be fully
994 instantiated, i.e. it cannot be a mere reference to (part of) an
995 existing object. */
997 {
1004 }
1006 /* Otherwise, see if we can proceed with a stabilized version of
1007 the renamed entity or if we need to make a new object. */
1009 {
1013 /* Case 2: If the renaming entity need not be materialized and
1014 the renamed expression is something we can stabilize, use
1015 that for the renaming. At the global level, we can only do
1016 this if we know no SAVE_EXPRs need be made, because the
1017 expression we return might be used in arbitrary conditional
1018 branches so we must force the evaluation of the SAVE_EXPRs
1019 immediately and this requires a proper function context.
1020 Note that an external constant is at the global level. */
1026 {
1027 maybe_stable_expr
1031 {
1032 /* ??? No DECL_EXPR is created so we need to mark
1033 the expression manually lest it is shared. */
1042 /* This assertion will fail if the renamed object
1043 isn't aligned enough as to make it possible to
1044 honor the alignment set on the renaming. */
1046 {
1047 unsigned int renamed_align
1052 }
1054 }
1056 /* The stabilization failed. Keep maybe_stable_expr
1057 untouched here to let the pointer case below know
1058 about that failure. */
1059 }
1061 /* Case 3: Make this into a constant pointer to the object we
1062 are to rename and attach the object to the pointer if it is
1063 something we can stabilize.
1065 From the proper scope, attached objects will be referenced
1066 directly instead of indirectly via the pointer to avoid
1067 subtle aliasing problems with non-addressable entities.
1068 They have to be stable because we must not evaluate the
1069 variables in the expression every time the renaming is used.
1070 The pointer is called a "renaming" pointer in this case.
1072 In the rare cases where we cannot stabilize the renamed
1073 object, we just make a "bare" pointer and the renamed
1074 object will always be accessed indirectly through it.
1076 Note that we need to preserve the volatility of the renamed
1077 object through the indirection. */
1079 gnu_type
1085 /* If the previous attempt at stabilizing failed, there is
1086 no point in trying again and we reuse the result without
1087 attaching it to the pointer. In this case it will only
1088 be used as the initializing expression of the pointer and
1089 thus needs no special treatment with regard to multiple
1090 evaluations.
1092 Otherwise, try to stabilize and attach the expression to
1093 the pointer if the stabilization succeeds.
1095 Note that this might introduce SAVE_EXPRs and we don't
1096 check whether we are at the global level or not. This
1097 is fine since we are building a pointer initializer and
1098 neither the pointer nor the initializing expression can
1099 be accessed before the pointer elaboration has taken
1100 place in a correct program.
1102 These SAVE_EXPRs will be evaluated at the right place
1103 by either the evaluation of the initializer for the
1104 non-global case or the elaboration code for the global
1105 case, and will be attached to the elaboration procedure
1106 in the latter case. */
1108 {
1109 maybe_stable_expr
1114 }
1119 else
1120 gnu_expr
1125 }
1126 }
1128 /* Make a volatile version of this object's type if we are to make
1129 the object volatile. We also interpret 13.3(19) conservatively
1130 and disallow any optimizations for such a non-constant object. */
1132 || (!const_flag
1135 || imported_p
1140 /* If we are defining an aliased object whose nominal subtype is
1141 unconstrained, the object is a record that contains both the
1142 template and the object. If there is an initializer, it will
1143 have already been converted to the right type, but we need to
1144 create the template if there is no initializer. */
1146 && !gnu_expr
1149 /* Beware that padding might have been introduced above. */
1152 == RECORD_TYPE
1153 && TYPE_CONTAINS_TEMPLATE_P
1155 {
1156 tree template_field
1164 NULL_TREE);
1167 }
1169 /* Convert the expression to the type of the object except in the
1170 case where the object's type is unconstrained or the object's type
1171 is a padded record whose field is of self-referential size. In
1172 the former case, converting will generate unnecessary evaluations
1173 of the CONSTRUCTOR to compute the size and in the latter case, we
1174 want to only copy the actual data. Also don't convert to a record
1175 type with a variant part from a record type without one, to keep
1176 the object simpler. */
1181 && CONTAINS_PLACEHOLDER_P
1189 /* If this is a pointer that doesn't have an initializing expression,
1190 initialize it to NULL, unless the object is imported. */
1193 && !gnu_expr
1197 /* If we are defining the object and it has an Address clause, we must
1198 either get the address expression from the saved GCC tree for the
1199 object if it has a Freeze node, or elaborate the address expression
1200 here since the front-end has guaranteed that the elaboration has no
1201 effects in this case. */
1203 {
1205 tree gnu_address
1211 /* Ignore the size. It's either meaningless or was handled
1212 above. */
1214 /* Convert the type of the object to a reference type that can
1215 alias everything as per 13.3(19). */
1216 gnu_type
1220 const_flag
1224 /* If this is a deferred constant, the initializer is attached to
1225 the full view. */
1227 gnu_expr
1228 = gnat_to_gnu
1231 /* If we don't have an initializing expression for the underlying
1232 variable, the initializing expression for the pointer is the
1233 specified address. Otherwise, we have to make a COMPOUND_EXPR
1234 to assign both the address and the initial value. */
1237 else
1238 gnu_expr
1240 build_binary_op
1243 gnu_address),
1244 gnu_expr),
1245 gnu_address);
1246 }
1248 /* If it has an address clause and we are not defining it, mark it
1249 as an indirect object. Likewise for Stdcall objects that are
1250 imported. */
1254 {
1255 /* Convert the type of the object to a reference type that can
1256 alias everything as per 13.3(19). */
1257 gnu_type
1261 /* No point in taking the address of an initializing expression
1262 that isn't going to be used. */
1265 /* If it has an address clause whose value is known at compile
1266 time, make the object a CONST_DECL. This will avoid a
1267 useless dereference. */
1269 {
1270 Node_Id gnat_address
1274 {
1277 }
1278 }
1281 }
1283 /* If we are at top level and this object is of variable size,
1284 make the actual type a hidden pointer to the real type and
1285 make the initializer be a memory allocation and initialization.
1286 Likewise for objects we aren't defining (presumed to be
1287 external references from other packages), but there we do
1288 not set up an initialization.
1290 If the object's size overflows, make an allocator too, so that
1291 Storage_Error gets raised. Note that we will never free
1292 such memory, so we presume it never will get allocated. */
1295 || !definition
1297 || (gnu_size
1299 size_binop
1301 bitsize_unit_node)),
1303 || !definition
1305 {
1310 /* In case this was a aliased object whose nominal subtype is
1311 unconstrained, the pointer above will be a thin pointer and
1312 build_allocator will automatically make the template.
1314 If we have a template initializer only (that we made above),
1315 pretend there is none and rely on what build_allocator creates
1316 again anyway. Otherwise (if we have a full initializer), get
1317 the data part and feed that to build_allocator.
1319 If we are elaborating a mutable object, tell build_allocator to
1320 ignore a possibly simpler size from the initializer, if any, as
1321 we must allocate the maximum possible size in this case. */
1323 {
1328 {
1329 gnu_alloc_type
1335 else
1336 gnu_expr
1337 = build_component_ref
1341 }
1346 gnat_entity);
1348 gnu_expr
1352 }
1353 else
1354 {
1357 }
1358 }
1360 /* If this object would go into the stack and has an alignment larger
1361 than the largest stack alignment the back-end can honor, resort to
1362 a variable of "aligning type". */
1365 {
1366 /* Create the new variable. No need for extra room before the
1367 aligned field as this is in automatic storage. */
1368 tree gnu_new_type
1372 tree gnu_new_var
1377 /* Initialize the aligned field if we have an initializer. */
1379 add_stmt_with_node
1381 build_component_ref
1384 gnu_expr),
1385 gnat_entity);
1387 /* And setup this entity as a reference to the aligned field. */
1389 gnu_expr
1390 = build_unary_op
1398 }
1400 /* If this is an aliased object with an unconstrained nominal subtype,
1401 we make its type a thin reference, i.e. the reference counterpart
1402 of a thin pointer, so that it points to the array part. This is
1403 aimed at making it easier for the debugger to decode the object.
1404 Note that we have to do that this late because of the couple of
1405 allocation adjustments that might be made just above. */
1409 {
1410 tree gnu_array
1413 /* In case the object with the template has already been allocated
1414 just above, we have nothing to do here. */
1416 {
1417 tree gnu_unc_var
1423 gnu_expr
1431 }
1433 gnu_type
1435 }
1440 /* Convert the expression to the type of the object except in the
1441 case where the object's type is unconstrained or the object's type
1442 is a padded record whose field is of self-referential size. In
1443 the former case, converting will generate unnecessary evaluations
1444 of the CONSTRUCTOR to compute the size and in the latter case, we
1445 want to only copy the actual data. Also don't convert to a record
1446 type with a variant part from a record type without one, to keep
1447 the object simpler. */
1452 && CONTAINS_PLACEHOLDER_P
1460 /* If this name is external or a name was specified, use it, but don't
1461 use the Interface_Name with an address clause (see cd30005). */
1468 /* If this is an aggregate constant initialized to a constant, force it
1469 to be statically allocated. This saves an initialization copy. */
1471 && const_flag
1480 /* Deal with a pragma Linker_Section on a constant or variable. */
1486 /* Now create the variable or the constant and set various flags. */
1487 gnu_decl
1496 /* If we are defining an Out parameter and optimization isn't enabled,
1497 create a fake PARM_DECL for debugging purposes and make it point to
1498 the VAR_DECL. Suppress debug info for the latter but make sure it
1499 will live in memory so that it can be accessed from within the
1500 debugger through the PARM_DECL. */
1502 && definition
1503 && debug_info_p
1504 && !optimize
1506 {
1513 }
1515 /* If this is a loop parameter, set the corresponding flag. */
1519 /* If this is a renaming pointer, attach the renamed object to it and
1520 register it if we are at the global level. Note that an external
1521 constant is at the global level. */
1523 {
1526 {
1529 }
1530 }
1532 /* If this is a constant and we are defining it or it generates a real
1533 symbol at the object level and we are referencing it, we may want
1534 or need to have a true variable to represent it:
1535 - if optimization isn't enabled, for debugging purposes,
1536 - if the constant is public and not overlaid on something else,
1537 - if its address is taken,
1538 - if either itself or its type is aliased. */
1547 {
1548 tree gnu_corr_var
1552 gnat_entity);
1556 /* As debugging information will be generated for the variable,
1557 do not generate debugging information for the constant. */
1560 else
1562 }
1564 /* If this is a constant, even if we don't need a true variable, we
1565 may need to avoid returning the initializer in every case. That
1566 can happen for the address of a (constant) constructor because,
1567 upon dereferencing it, the constructor will be reinjected in the
1568 tree, which may not be valid in every case; see lvalue_required_p
1569 for more details. */
1573 /* If this object is declared in a block that contains a block with an
1574 exception handler, and we aren't using the GCC exception mechanism,
1575 we must force this variable in memory in order to avoid an invalid
1576 optimization. */
1581 /* If this is a local variable with non-BLKmode and aggregate type,
1582 and optimization isn't enabled, then force it in memory so that
1583 a register won't be allocated to it with possible subparts left
1584 uninitialized and reaching the register allocator. */
1594 /* If we are defining an object with variable size or an object with
1595 fixed size that will be dynamically allocated, and we are using the
1596 setjmp/longjmp exception mechanism, update the setjmp buffer. */
1609 gnat_entity);
1611 /* Back-annotate Esize and Alignment of the object if not already
1612 known. Note that we pick the values of the type, not those of
1613 the object, to shield ourselves from low-level platform-dependent
1614 adjustments like alignment promotion. This is both consistent with
1615 all the treatment above, where alignment and size are set on the
1616 type of the object and not on the object directly, and makes it
1617 possible to support all confirming representation clauses. */
1619 used_by_ref);
1620 }
1624 /* Return a TYPE_DECL for "void" that we previously made. */
1629 /* A special case: for the types Character and Wide_Character in
1630 Standard, we do not list all the literals. So if the literals
1631 are not specified, make this an unsigned integer type. */
1633 {
1637 /* Set TYPE_STRING_FLAG for Character and Wide_Character types.
1638 This is needed by the DWARF-2 back-end to distinguish between
1639 unsigned integer types and character types. */
1641 }
1642 else
1643 {
1644 /* We have a list of enumeral constants in First_Literal. We make a
1645 CONST_DECL for each one and build into GNU_LITERAL_LIST the list
1646 to be placed into TYPE_FIELDS. Each node is itself a TREE_LIST
1647 whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
1648 value of the literal. But when we have a regular boolean type, we
1649 simplify this a little by using a BOOLEAN_TYPE. */
1654 Entity_Id gnat_literal;
1667 {
1668 tree gnu_value
1670 tree gnu_literal
1674 /* Do not generate debug info for individual enumerators. */
1677 gnu_list
1679 }
1684 /* Note that the bounds are updated at the end of this function
1685 to avoid an infinite recursion since they refer to the type. */
1687 }
1693 /* For integer types, just make a signed type the appropriate number
1694 of bits. */
1699 {
1700 /* For modular types, make the unsigned type of the proper number
1701 of bits and then set up the modulus, if required. */
1704 /* Packed Array Impl. Types are supposed to be subtypes only. */
1709 /* Get the modulus in this type. If it overflows, assume it is because
1710 it is equal to 2**Esize. Note that there is no overflow checking
1711 done on unsigned type, so we detect the overflow by looking for
1712 a modulus of zero, which is otherwise invalid. */
1716 {
1721 }
1723 /* If the upper bound is not maximal, make an extra subtype. */
1726 {
1733 }
1734 }
1743 /* For integral subtypes, we make a new INTEGER_TYPE. Note that we do
1744 not want to call create_range_type since we would like each subtype
1745 node to be distinct. ??? Historically this was in preparation for
1746 when memory aliasing is implemented, but that's obsolete now given
1747 the call to relate_alias_sets below.
1749 The TREE_TYPE field of the INTEGER_TYPE points to the base type;
1750 this fact is used by the arithmetic conversion functions.
1752 We elaborate the Ancestor_Subtype if it is not in the current unit
1753 and one of our bounds is non-static. We do this to ensure consistent
1754 naming in the case where several subtypes share the same bounds, by
1755 elaborating the first such subtype first, thus using its name. */
1764 /* Set the precision to the Esize except for bit-packed arrays. */
1769 /* This should be an unsigned type if the base type is unsigned or
1770 if the lower bound is constant and non-negative or if the type
1771 is biased. */
1776 else
1780 SET_TYPE_RM_MIN_VALUE
1786 SET_TYPE_RM_MAX_VALUE
1795 /* Inherit our alias set from what we're a subtype of. Subtypes
1796 are not different types and a pointer can designate any instance
1797 within a subtype hierarchy. */
1800 /* One of the above calls might have caused us to be elaborated,
1801 so don't blow up if so. */
1803 {
1806 }
1808 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
1812 /* For a packed array, make the original array type a parallel type. */
1816 discrete_type:
1818 /* We have to handle clauses that under-align the type specially. */
1821 && Present
1824 {
1828 }
1830 /* If the type we are dealing with represents a bit-packed array,
1831 we need to have the bits left justified on big-endian targets
1832 and right justified on little-endian targets. We also need to
1833 ensure that when the value is read (e.g. for comparison of two
1834 such values), we only get the good bits, since the unused bits
1835 are uninitialized. Both goals are accomplished by wrapping up
1836 the modular type in an enclosing record type. */
1839 {
1842 /* Set the RM size before wrapping up the original type. */
1847 /* Create a stripped-down declaration, mainly for debugging. */
1849 gnat_entity);
1851 /* Now save it and build the enclosing record type. */
1861 /* Propagate the alignment of the modular type to the record type,
1862 unless there is an alignment clause that under-aligns the type.
1863 This means that bit-packed arrays are given "ceil" alignment for
1864 their size by default, which may seem counter-intuitive but makes
1865 it possible to overlay them on modular types easily. */
1871 /* Don't declare the field as addressable since we won't be taking
1872 its address and this would prevent create_field_decl from making
1873 a bitfield. */
1874 gnu_field
1878 /* Do not emit debug info until after the parallel type is added. */
1884 {
1885 /* Make the original array type a parallel type. */
1889 }
1890 }
1892 /* If the type we are dealing with has got a smaller alignment than the
1893 natural one, we need to wrap it up in a record type and misalign the
1894 latter; we reuse the padding machinery for this purpose. Note that,
1895 even if the record type is marked as packed because of misalignment,
1896 we don't pack the field so as to give it the size of the type. */
1898 {
1901 /* Set the RM size before wrapping up the type. */
1905 /* Create a stripped-down declaration, mainly for debugging. */
1907 gnat_entity);
1909 /* Now save it and build the enclosing record type. */
1921 /* Don't declare the field as addressable since we won't be taking
1922 its address and this would prevent create_field_decl from making
1923 a bitfield. */
1924 gnu_field
1932 }
1937 /* The type of the Low and High bounds can be our type if this is
1938 a type from Standard, so set them at the end of the function. */
1945 /* See the E_Signed_Integer_Subtype case for the rationale. */
1962 SET_TYPE_RM_MIN_VALUE
1968 SET_TYPE_RM_MAX_VALUE
1974 /* Inherit our alias set from what we're a subtype of, as for
1975 integer subtypes. */
1978 /* One of the above calls might have caused us to be elaborated,
1979 so don't blow up if so. */
1983 /* Array Types and Subtypes
1985 Unconstrained array types are represented by E_Array_Type and
1986 constrained array types are represented by E_Array_Subtype. There
1987 are no actual objects of an unconstrained array type; all we have
1988 are pointers to that type.
1990 The following fields are defined on array types and subtypes:
1992 Component_Type Component type of the array.
1993 Number_Dimensions Number of dimensions (an int).
1994 First_Index Type of first index. */
1997 {
1998 const bool convention_fortran_p
2001 tree gnu_template_type;
2002 tree gnu_ptr_template;
2009 tree comp_type;
2011 /* Create the type for the component now, as it simplifies breaking
2012 type reference loops. */
2013 comp_type
2016 {
2017 /* As a side effect, the type may have been translated. */
2020 }
2022 /* We complete an existing dummy fat pointer type in place. This both
2023 avoids further complex adjustments in update_pointer_to and yields
2024 better debugging information in DWARF by leveraging the support for
2025 incomplete declarations of "tagged" types in the DWARF back-end. */
2028 {
2031 /* Save the contents of the dummy type for update_pointer_to. */
2033 gnu_ptr_template =
2036 }
2037 else
2038 {
2042 }
2044 /* Make a node for the array. If we are not defining the array
2045 suppress expanding incomplete types. */
2049 {
2050 defer_incomplete_level++;
2052 }
2054 /* Build the fat pointer type. Use a "void *" object instead of
2055 a pointer to the array type since we don't have the array type
2056 yet (it will reference the fat pointer via the bounds). */
2057 tem
2065 {
2066 /* We are going to lay it out again so reset the alias set. */
2072 {
2075 }
2076 }
2077 else
2078 {
2081 }
2083 /* Build a reference to the template from a PLACEHOLDER_EXPR that
2084 is the fat pointer. This will be used to access the individual
2085 fields once we build them. */
2089 gnu_template_reference
2094 /* Now create the GCC type for each index and add the fields for that
2095 index to the template. */
2101 {
2103 tree gnu_index_base_type
2108 /* Make the FIELD_DECLs for the low and high bounds of this
2109 type and then make extractions of these fields from the
2110 template. */
2113 gnu_index_base_type,
2121 gnu_index_base_type,
2129 /* We can't use build_component_ref here since the template type
2130 isn't complete yet. */
2133 NULL_TREE);
2136 NULL_TREE);
2142 /* Compute the size of this dimension. See the E_Array_Subtype
2143 case below for the rationale. */
2144 gnu_high
2148 gnu_max,
2151 /* Make a range type with the new range in the Ada base type.
2152 Then make an index type with the size range in sizetype. */
2156 gnu_orig_min,
2157 gnu_orig_max),
2158 gnat_entity);
2160 /* Update the maximum size of the array in elements. */
2162 {
2164 tree gnu_min
2166 tree gnu_max
2168 tree gnu_this_max
2175 else
2176 gnu_max_size
2178 }
2182 }
2184 /* Install all the fields into the template. */
2189 gnu_template_fields
2192 debug_info_p);
2195 /* If Component_Size is not already specified, annotate it with the
2196 size of the component. */
2201 /* Compute the maximum size of the array in units and bits. */
2203 {
2209 }
2210 else
2213 /* Now build the array type. */
2216 {
2224 /* If it is passed by reference, force BLKmode to ensure that
2225 objects of this type will always be put in memory. */
2229 }
2233 /* If an alignment is specified, use it if valid. But ignore it
2234 for the original type of packed array types. If the alignment
2235 was requested with an explicit alignment clause, state so. */
2238 {
2244 }
2248 /* Adjust the type of the pointer-to-array field of the fat pointer
2249 and record the aliasing relationships if necessary. */
2254 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2255 corresponding fat pointer. */
2262 /* If the maximum size doesn't overflow, use it. */
2268 {
2273 }
2277 gnat_entity);
2279 /* Give the fat pointer type a name. If this is a packed array, tell
2280 the debugger how to interpret the underlying bits. */
2283 else
2287 gnat_entity);
2289 /* Create the type to be designated by thin pointers: a record type for
2290 the array and its template. We used to shift the fields to have the
2291 template at a negative offset, but this was somewhat of a kludge; we
2292 now shift thin pointer values explicitly but only those which have a
2293 TYPE_UNCONSTRAINED_ARRAY attached to the designated RECORD_TYPE. */
2296 debug_info_p);
2300 }
2305 /* This is the actual data type for array variables. Multidimensional
2306 arrays are implemented as arrays of arrays. Note that arrays which
2307 have sparse enumeration subtypes as index components create sparse
2308 arrays, which is obviously space inefficient but so much easier to
2309 code for now.
2311 Also note that the subtype never refers to the unconstrained array
2312 type, which is somewhat at variance with Ada semantics.
2314 First check to see if this is simply a renaming of the array type.
2315 If so, the result is the array type. */
2319 ;
2320 else
2321 {
2323 const bool convention_fortran_p
2332 /* First create the GCC type for each index and find out whether
2333 special types are needed for debugging information. */
2336 gnat_base_index
2342 {
2345 tree gnu_orig_min
2348 tree gnu_orig_max
2353 tree gnu_base_index_type
2355 tree gnu_base_index_base_type
2357 tree gnu_base_orig_min
2360 tree gnu_base_orig_max
2363 tree gnu_high;
2365 /* See if the base array type is already flat. If it is, we
2366 are probably compiling an ACATS test but it will cause the
2367 code below to malfunction if we don't handle it specially. */
2371 {
2375 }
2377 /* Similarly, if one of the values overflows in sizetype and the
2378 range is null, use 1..0 for the sizetype bounds. */
2383 {
2387 }
2389 /* If the minimum and maximum values both overflow in sizetype,
2390 but the difference in the original type does not overflow in
2391 sizetype, ignore the overflow indication. */
2395 && !TREE_OVERFLOW
2398 gnu_orig_max,
2399 gnu_orig_min))))
2400 {
2404 }
2406 /* Compute the size of this dimension in the general case. We
2407 need to provide GCC with an upper bound to use but have to
2408 deal with the "superflat" case. There are three ways to do
2409 this. If we can prove that the array can never be superflat,
2410 we can just use the high bound of the index type. */
2413 /* Bit-Packed Array Impl. Types are never superflat. */
2415 && Is_Bit_Packed_Array
2419 /* Otherwise, if the high bound is constant but the low bound is
2420 not, we use the expression (hb >= lb) ? lb : hb + 1 for the
2421 lower bound. Note that the comparison must be done in the
2422 original type to avoid any overflow during the conversion. */
2425 {
2427 gnu_min
2430 boolean_type_node,
2431 gnu_orig_max,
2432 gnu_orig_min),
2433 gnu_min,
2435 size_one_node));
2436 }
2438 /* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
2439 in all the other cases. Note that, here as well as above,
2440 the condition used in the comparison must be equivalent to
2441 the condition (length != 0). This is relied upon in order
2442 to optimize array comparisons in compare_arrays. Moreover
2443 we use int_const_binop for the shift by 1 if the bound is
2444 constant to avoid any unwanted overflow. */
2445 else
2446 gnu_high
2449 boolean_type_node,
2450 gnu_orig_max,
2451 gnu_orig_min),
2452 gnu_max,
2455 size_one_node)
2457 size_one_node));
2459 /* Reuse the index type for the range type. Then make an index
2460 type with the size range in sizetype. */
2463 gnat_entity);
2465 /* Update the maximum size of the array in elements. Here we
2466 see if any constraint on the index type of the base type
2467 can be used in the case of self-referential bound on the
2468 index type of the subtype. We look for a non-"infinite"
2469 and non-self-referential bound from any type involved and
2470 handle each bound separately. */
2472 {
2475 tree gnu_base_index_base_type
2477 tree gnu_base_base_min
2480 tree gnu_base_base_max
2501 else
2502 {
2503 tree gnu_this_max;
2505 /* Use int_const_binop if the bounds are constant to
2506 avoid any unwanted overflow. */
2509 gnu_this_max
2512 gnu_base_max,
2513 gnu_base_min));
2514 else
2515 gnu_this_max
2518 gnu_base_max,
2519 gnu_base_min));
2521 gnu_max_size
2523 }
2524 }
2526 /* We need special types for debugging information to point to
2527 the index types if they have variable bounds, are not integer
2528 types or are biased. */
2537 }
2539 /* Then flatten: create the array of arrays. For an array type
2540 used to implement a packed array, get the component type from
2541 the original array type since the representation clauses that
2542 can affect it are on the latter. */
2545 {
2550 /* One of the above calls might have caused us to be elaborated,
2551 so don't blow up if so. */
2553 {
2556 }
2557 }
2558 else
2559 {
2561 debug_info_p);
2563 /* One of the above calls might have caused us to be elaborated,
2564 so don't blow up if so. */
2566 {
2569 }
2570 }
2572 /* Compute the maximum size of the array in units and bits. */
2574 {
2580 }
2581 else
2584 /* Now build the array type. */
2586 {
2593 /* See the E_Array_Type case for the rationale. */
2597 }
2601 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
2605 /* If we are at file level and this is a multi-dimensional array,
2606 we need to make a variable corresponding to the stride of the
2607 inner dimensions. */
2609 {
2611 tree gnu_arr_type;
2617 {
2625 /* ??? For now, store the size as a multiple of the
2626 alignment of the element type in bytes so that we
2627 can see the alignment from the tree. */
2630 gnat_entity,
2635 /* ??? create_type_decl is not invoked on the inner types so
2636 the MULT_EXPR node built above will never be marked. */
2638 }
2639 }
2641 /* If we need to write out a record type giving the names of the
2642 bounds for debugging purposes, do it now and make the record
2643 type a parallel type. This is not needed for a packed array
2644 since the bounds are conveyed by the original array type. */
2646 && debug_info_p
2648 {
2651 tree gnu_field;
2657 {
2661 /* Make sure to reference the types themselves, and not just
2662 their names, as the debugger may fall back on them. */
2668 }
2672 }
2674 /* If this is a packed array type, make the original array type a
2675 parallel type. Otherwise, do it for the base array type if it
2676 isn't artificial to make sure it is kept in the debug info. */
2678 {
2681 else
2682 {
2683 tree gnu_base_decl
2688 }
2689 }
2696 /* If the size is self-referential and the maximum size doesn't
2697 overflow, use it. */
2699 && gnu_max_size
2704 {
2710 }
2712 /* Set our alias set to that of our base type. This gives all
2713 array subtypes the same alias set. */
2716 /* If this is a packed type, make this type the same as the packed
2717 array type, but do some adjusting in the type first. */
2719 {
2720 Entity_Id gnat_index;
2721 tree gnu_inner;
2723 /* First finish the type we had been making so that we output
2724 debugging information for it. */
2727 gnu_type
2729 /* Make it artificial only if the base type was artificial too.
2730 That's sort of "morally" true and will make it possible for
2731 the debugger to look it up by name in DWARF, which is needed
2732 in order to decode the packed array type. */
2733 gnu_decl
2739 /* Save it as our equivalent in case the call below elaborates
2740 this type again. */
2743 gnu_decl
2756 /* We need to attach the index type to the type we just made so
2757 that the actual bounds can later be put into a template. */
2762 {
2764 {
2765 /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
2766 TYPE_MODULUS for modular types so we make an extra
2767 subtype if necessary. */
2769 {
2770 tree gnu_subtype
2779 }
2783 #ifdef ENABLE_CHECKING
2784 /* Check for other cases of overloading. */
2786 #endif
2787 }
2792 SET_TYPE_ACTUAL_BOUNDS
2799 SET_TYPE_ACTUAL_BOUNDS
2805 }
2806 }
2808 else
2809 /* Abort if packed array with no Packed_Array_Impl_Type. */
2811 }
2815 /* Create the type for a string literal. */
2816 {
2817 Entity_Id gnat_full_type
2822 tree gnu_string_array_type
2824 tree gnu_string_index_type
2827 tree gnu_lower_bound
2830 tree gnu_length
2832 gnu_string_index_type);
2833 tree gnu_upper_bound
2835 gnu_lower_bound,
2838 integer_one_node)));
2839 tree gnu_index_type
2843 gnu_lower_bound,
2844 gnu_upper_bound),
2845 gnat_entity);
2847 gnu_type
2850 gnu_index_type);
2854 }
2857 /* Record Types and Subtypes
2859 The following fields are defined on record types:
2861 Has_Discriminants True if the record has discriminants
2862 First_Discriminant Points to head of list of discriminants
2863 First_Entity Points to head of list of fields
2864 Is_Tagged_Type True if the record is tagged
2866 Implementation of Ada records and discriminated records:
2868 A record type definition is transformed into the equivalent of a C
2869 struct definition. The fields that are the discriminants which are
2870 found in the Full_Type_Declaration node and the elements of the
2871 Component_List found in the Record_Type_Definition node. The
2872 Component_List can be a recursive structure since each Variant of
2873 the Variant_Part of the Component_List has a Component_List.
2875 Processing of a record type definition comprises starting the list of
2876 field declarations here from the discriminants and the calling the
2877 function components_to_record to add the rest of the fields from the
2878 component list and return the gnu type node. The function
2879 components_to_record will call itself recursively as it traverses
2880 the tree. */
2884 {
2885 gnu_type
2886 = build_complex_type
2887 (get_unpadded_type
2890 (Component_List
2891 (Type_Definition
2895 }
2897 {
2900 Node_Id gnat_constr;
2901 Entity_Id gnat_field;
2903 tree gnu_get_parent;
2904 /* Set PACKED in keeping with gnat_to_gnu_field. */
2905 const int packed
2917 const bool is_extension
2923 /* See if all fields have a rep clause. Stop when we find one
2924 that doesn't. */
2932 {
2935 }
2937 /* If this is a record extension, go a level further to find the
2938 record definition. Also, verify we have a Parent_Subtype. */
2940 {
2947 }
2949 /* Make a node for the record. If we are not defining the record,
2950 suppress expanding incomplete types. */
2959 {
2960 defer_incomplete_level++;
2962 }
2964 /* If both a size and rep clause was specified, put the size in
2965 the record type now so that it can get the proper mode. */
2970 /* Always set the alignment here so that it can be used to
2971 set the mode, if it is making the alignment stricter. If
2972 it is invalid, it will be checked again below. If this is to
2973 be Atomic, choose a default alignment of a word unless we know
2974 the size and it's smaller. */
2979 {
2983 }
2984 /* If a type needs strict alignment, the minimum size will be the
2985 type size instead of the RM size (see validate_size). Cap the
2986 alignment, lest it causes this type size to become too large. */
2988 {
2993 }
2994 else
2997 /* If we have a Parent_Subtype, make a field for the parent. If
2998 this record has rep clauses, force the position to zero. */
3000 {
3003 tree gnu_parent;
3005 /* A major complexity here is that the parent subtype will
3006 reference our discriminants in its Stored_Constraint list.
3007 But those must reference the parent component of this record
3008 which is precisely of the parent subtype we have not built yet!
3009 To break the circle we first build a dummy COMPONENT_REF which
3010 represents the "get to the parent" operation and initialize
3011 each of those discriminants to a COMPONENT_REF of the above
3012 dummy parent referencing the corresponding discriminant of the
3013 base type of the parent subtype. */
3018 gnu_dummy_parent_type),
3019 NULL_TREE);
3026 {
3027 tree gnu_field
3030 save_gnu_tree
3035 }
3037 /* Then we build the parent subtype. If it has discriminants but
3038 the type itself has unknown discriminants, this means that it
3039 doesn't contain information about how the discriminants are
3040 derived from those of the ancestor type, so it cannot be used
3041 directly. Instead it is built by cloning the parent subtype
3042 of the underlying record view of the type, for which the above
3043 derivation of discriminants has been made explicit. */
3046 {
3049 /* If we are defining the type, the underlying record
3050 view must already have been elaborated at this point.
3051 Otherwise do it now as its parent subtype cannot be
3052 technically elaborated on its own. */
3055 else
3060 /* Substitute the "get to the parent" of the type for that
3061 of its underlying record view in the cloned type. */
3066 {
3068 tree gnu_ref
3071 gnu_parent
3073 }
3074 }
3075 else
3078 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
3079 initially built. The discriminants must reference the fields
3080 of the parent subtype and not those of its base type for the
3081 placeholder machinery to properly work. */
3083 {
3084 /* The actual parent subtype is the full view. */
3086 {
3089 else
3091 }
3097 {
3098 Entity_Id field;
3107 }
3108 }
3110 /* The "get to the parent" COMPONENT_REF must be given its
3111 proper type... */
3114 /* ...and reference the _Parent field of this record. */
3115 gnu_field
3118 has_rep
3120 has_rep
3126 }
3128 /* Make the fields for the discriminants and put them into the record
3129 unless it's an Unchecked_Union. */
3134 {
3135 /* If this is a record extension and this discriminant is the
3136 renaming of another discriminant, we've handled it above. */
3141 gnu_field
3143 debug_info_p);
3145 /* Make an expression using a PLACEHOLDER_EXPR from the
3146 FIELD_DECL node just created and link that with the
3147 corresponding GNAT defining identifier. */
3155 {
3158 }
3159 }
3161 /* If we have a derived untagged type that renames discriminants in
3162 the root type, the (stored) discriminants are a just copy of the
3163 discriminants of the root type. This means that any constraints
3164 added by the renaming in the derivation are disregarded as far
3165 as the layout of the derived type is concerned. To rescue them,
3166 we change the type of the (stored) discriminants to a subtype
3167 with the bounds of the type of the visible discriminants. */
3169 && !is_extension
3175 /* Ignore access discriminants. */
3178 {
3182 /* If the scope of the discriminant is not the record type,
3183 this means that we're processing the implicit full view
3184 of a type derived from a private discriminated type: in
3185 this case, the Stored_Constraint list is simply copied
3186 from the partial view, see Build_Derived_Private_Type.
3187 So we need to retrieve the corresponding discriminant
3188 of the implicit full view, otherwise we will abort. */
3190 {
3191 Entity_Id field;
3200 }
3203 gnu_ref
3207 /* GNU_REF must be an expression using a PLACEHOLDER_EXPR built
3208 just above for one of the stored discriminants. */
3212 {
3214 tree gnu_subtype
3225 }
3226 }
3228 /* Add the fields into the record type and finish it up. */
3236 /* If it is passed by reference, force BLKmode to ensure that objects
3237 of this type will always be put in memory. */
3244 /* Fill in locations of fields. */
3247 /* If there are any entities in the chain corresponding to components
3248 that we did not elaborate, ensure we elaborate their types if they
3249 are Itypes. */
3259 /* If this is a record type associated with an exception definition,
3260 equate its fields to those of the standard exception type. This
3261 will make it possible to convert between them. */
3263 {
3264 tree gnu_std_field;
3267 gnu_field;
3272 }
3273 }
3277 /* If an equivalent type is present, that is what we should use.
3278 Otherwise, fall through to handle this like a record subtype
3279 since it may have constraints. */
3281 {
3285 }
3287 /* ... fall through ... */
3290 /* If Cloned_Subtype is Present it means this record subtype has
3291 identical layout to that type or subtype and we should use
3292 that GCC type for this one. The front end guarantees that
3293 the component list is shared. */
3295 {
3300 }
3302 /* Otherwise, first ensure the base type is elaborated. Then, if we are
3303 changing the type, make a new type with each field having the type of
3304 the field in the new subtype but the position computed by transforming
3305 every discriminant reference according to the constraints. We don't
3306 see any difference between private and non-private type here since
3307 derivations from types should have been deferred until the completion
3308 of the private type. */
3309 else
3310 {
3312 tree gnu_base_type;
3315 {
3316 defer_incomplete_level++;
3318 }
3323 {
3326 }
3328 /* If this is a record subtype associated with a dispatch table,
3329 strip the suffix. This is necessary to make sure 2 different
3330 subtypes associated with the imported and exported views of a
3331 dispatch table are properly merged in LTO mode. */
3333 {
3340 }
3342 /* When the subtype has discriminants and these discriminants affect
3343 the initial shape it has inherited, factor them in. But for an
3344 Unchecked_Union (it must be an Itype), just return the type.
3345 We can't just test Is_Constrained because private subtypes without
3346 discriminants of types with discriminants with default expressions
3347 are Is_Constrained but aren't constrained! */
3354 {
3360 Entity_Id gnat_field;
3368 /* Set the size, alignment and alias set of the new type to
3369 match that of the old one, doing required substitutions. */
3371 gnu_subst_list);
3375 else
3378 /* Look for REP and variant parts in the base type. */
3382 /* If there is a variant part, we must compute whether the
3383 constraints statically select a particular variant. If
3384 so, we simply drop the qualified union and flatten the
3385 list of fields. Otherwise we'll build a new qualified
3386 union for the variants that are still relevant. */
3388 {
3392 gnu_variant_list
3394 gnu_subst_list,
3395 vNULL);
3397 /* If all the qualifiers are unconditionally true, the
3398 innermost variant is statically selected. */
3402 {
3405 }
3407 /* Otherwise, create the new variants. */
3410 {
3413 tree suffix
3415 IDENTIFIER_POINTER
3421 gnu_subst_list);
3423 }
3424 }
3425 else
3426 {
3429 }
3431 /* Make a list of fields and their position in the base type. */
3432 gnu_pos_list
3439 /* Now go down every component in the subtype and compute its
3440 size and position from those of the component in the base
3441 type and from the constraints of the subtype. */
3449 && Underlying_Type
3452 {
3454 Entity_Id gnat_old_field
3456 tree gnu_old_field
3462 /* If the type is the same, retrieve the GCC type from the
3463 old field to take into account possible adjustments. */
3466 else
3469 /* If there was a component clause, the field types must be
3470 the same for the type and subtype, so copy the data from
3471 the old field to avoid recomputation here. Also if the
3472 field is justified modular and the optimization in
3473 gnat_to_gnu_field was applied. */
3479 {
3482 }
3484 /* If the old field was packed and of constant size, we
3485 have to get the old size here, as it might differ from
3486 what the Etype conveys and the latter might overlap
3487 onto the following field. Try to arrange the type for
3488 possible better packing along the way. */
3492 {
3497 gnu_field_type
3499 }
3501 else
3504 /* If the context of the old field is the base type or its
3505 REP part (if any), put the field directly in the new
3506 type; otherwise look up the context in the variant list
3507 and put the field either in the new type if there is a
3508 selected variant or in one of the new variants. */
3510 || (gnu_rep_part
3513 else
3514 {
3517 tree rep_part;
3525 {
3528 else
3530 }
3531 else
3532 /* The front-end may pass us "ghost" components if
3533 it fails to recognize that a constrained subtype
3534 is statically constrained. Discard them. */
3536 }
3538 /* Now create the new field modeled on the old one. */
3539 gnu_field
3545 /* Put it in one of the new variants directly. */
3547 {
3550 }
3552 /* To match the layout crafted in components_to_record,
3553 if this is the _Tag or _Parent field, put it before
3554 any other fields. */
3559 /* Similarly, if this is the _Controller field, put
3560 it before the other fields except for the _Tag or
3561 _Parent field. */
3563 {
3566 }
3568 /* Otherwise, if this is a regular field, put it after
3569 the other fields. */
3570 else
3571 {
3578 }
3581 }
3583 /* If there is a variant list, a selected variant and the fields
3584 all have a constant position, put them in order of increasing
3585 position to match that of constant CONSTRUCTORs. Likewise if
3586 there is no variant list but a REP part, since the latter has
3587 been flattened in the process. */
3591 {
3603 {
3606 }
3607 }
3609 /* If there is a variant list and no selected variant, we need
3610 to create the nest of variant parts from the old nest. */
3612 {
3613 tree new_variant_part
3619 }
3621 /* Now go through the entities again looking for Itypes that
3622 we have not elaborated but should (e.g., Etypes of fields
3623 that have Original_Components). */
3631 /* Do not emit debug info for the type yet since we're going to
3632 modify it below. */
3637 /* See the E_Record_Type case for the rationale. */
3644 /* Fill in locations of fields. */
3647 /* If debugging information is being written for the type, write
3648 a record that shows what we are a subtype of and also make a
3649 variable that indicates our size, if still variable. */
3651 {
3653 tree gnu_unpad_base_name
3661 build_reference_type
3663 gnu_subtype_marker,
3678 gnat_entity);
3679 }
3684 /* Now we can finalize it. */
3686 }
3688 /* Otherwise, go down all the components in the new type and make
3689 them equivalent to those in the base type. */
3690 else
3691 {
3701 gnat_to_gnu_field_decl
3704 }
3705 }
3709 /* Use the special descriptor type for dispatch tables if needed,
3710 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3711 Note that we are only required to do so for static tables in
3712 order to be compatible with the C++ ABI, but Ada 2005 allows
3713 to extend library level tagged types at the local level so
3714 we do it in the non-static case as well. */
3717 {
3721 }
3723 /* ... fall through ... */
3726 /* If we are not defining this entity, and we have incomplete
3727 entities being processed above us, make a dummy type and
3728 fill it in later. */
3730 {
3733 gnu_type
3734 = build_pointer_type
3749 }
3751 /* ... fall through ... */
3758 {
3759 /* The designated type and its equivalent type for gigi. */
3762 /* Whether it comes from a limited with. */
3763 bool is_from_limited_with
3766 /* The "full view" of the designated type. If this is an incomplete
3767 entity from a limited with, treat its non-limited view as the full
3768 view. Otherwise, if this is an incomplete or private type, use the
3769 full view. In the former case, we might point to a private type,
3770 in which case, we need its full view. Also, we want to look at the
3771 actual type used for the representation, so this takes a total of
3772 three steps. */
3773 Entity_Id gnat_desig_full_direct_first
3774 = (is_from_limited_with
3778 Entity_Id gnat_desig_full_direct
3779 = ((is_from_limited_with
3784 Entity_Id gnat_desig_full
3786 /* The type actually used to represent the designated type, either
3787 gnat_desig_full or gnat_desig_equiv. */
3788 Entity_Id gnat_desig_rep;
3789 /* True if this is a pointer to an unconstrained array. */
3791 /* We want to know if we'll be seeing the freeze node for any
3792 incomplete type we may be pointing to. */
3793 bool in_main_unit
3797 /* True if we make a dummy type here. */
3799 /* The mode to be used for the pointer type. */
3801 /* The GCC type used for the designated type. */
3807 /* If either the designated type or its full view is an unconstrained
3808 array subtype, replace it with the type it's a subtype of. This
3809 avoids problems with multiple copies of unconstrained array types.
3810 Likewise, if the designated type is a subtype of an incomplete
3811 record type, use the parent type to avoid order of elaboration
3812 issues. This can lose some code efficiency, but there is no
3813 alternative. */
3824 /* Set the type that's actually the representation of the designated
3825 type and also flag whether we have a unconstrained array. */
3826 gnat_desig_rep
3828 is_unconstrained_array
3831 /* If we are pointing to an incomplete type whose completion is an
3832 unconstrained array, make dummy fat and thin pointer types to it.
3833 Likewise if the type itself is dummy or an unconstrained array. */
3837 && TYPE_IS_DUMMY_P
3839 || (!in_main_unit
3842 || (in_main_unit
3843 && is_from_limited_with
3845 {
3848 else
3849 {
3852 }
3854 /* If the call above got something that has a pointer, the pointer
3855 is our type. This could have happened either because the type
3856 was elaborated or because somebody else executed the code. */
3860 }
3862 /* If we already know what the full type is, use it. */
3867 /* Get the type of the thing we are to point to and build a pointer to
3868 it. If it is a reference to an incomplete or private type with a
3869 full view that is a record, make a dummy type node and get the
3870 actual type later when we have verified it is safe. */
3876 /* Likewise if we are pointing to a record or array and we are
3877 to defer elaborating incomplete types. We do this as this
3878 access type may be the full view of a private type. Note
3879 that the unconstrained array case is handled above. */
3885 /* If this is a reference from a limited_with type back to our
3886 main unit and there's a freeze node for it, either we have
3887 already processed the declaration and made the dummy type,
3888 in which case we just reuse the latter, or we have not yet,
3889 in which case we make the dummy type and it will be reused
3890 when the declaration is finally processed. In both cases,
3891 the pointer eventually created below will be automatically
3892 adjusted when the freeze node is processed. Note that the
3893 unconstrained array case is handled above. */
3894 || (in_main_unit
3895 && is_from_limited_with
3897 {
3900 }
3902 /* Otherwise handle the case of a pointer to itself. */
3904 {
3905 gnu_type
3909 }
3911 /* If expansion is disabled, the equivalent type of a concurrent type
3912 is absent, so build a dummy pointer type. */
3916 /* Finally, handle the default case where we can just elaborate our
3917 designated type. */
3918 else
3921 /* It is possible that a call to gnat_to_gnu_type above resolved our
3922 type. If so, just return it. */
3924 {
3927 }
3929 /* If we haven't done it yet, build the pointer type the usual way. */
3931 {
3932 /* Modify the designated type if we are pointing only to constant
3933 objects, but don't do it for unconstrained arrays. */
3936 {
3937 gnu_desig_type
3940 /* Some extra processing is required if we are building a
3941 pointer to an incomplete type (in the GCC sense). We might
3942 have such a type if we just made a dummy, or directly out
3943 of the call to gnat_to_gnu_type above if we are processing
3944 an access type for a record component designating the
3945 record type itself. */
3947 {
3948 /* We must ensure that the pointer to variant we make will
3949 be processed by update_pointer_to when the initial type
3950 is completed. Pretend we made a dummy and let further
3951 processing act as usual. */
3954 /* We must ensure that update_pointer_to will not retrieve
3955 the dummy variant when building a properly qualified
3956 version of the complete type. We take advantage of the
3957 fact that get_qualified_type is requiring TYPE_NAMEs to
3958 match to influence build_qualified_type and then also
3959 update_pointer_to here. */
3962 }
3963 }
3965 gnu_type
3968 }
3970 /* If we are not defining this object and we have made a dummy pointer,
3971 save our current definition, evaluate the actual type, and replace
3972 the tentative type we made with the actual one. If we are to defer
3973 actually looking up the actual type, make an entry in the deferred
3974 list. If this is from a limited with, we may have to defer to the
3975 end of the current unit. */
3977 {
3978 tree gnu_old_desig_type;
3981 {
3984 gnu_type = build_pointer_type
3986 }
3987 else
3999 /* Note that the call to gnat_to_gnu_type on gnat_desig_equiv might
4000 update gnu_old_desig_type directly, in which case it will not be
4001 a dummy type any more when we get into update_pointer_to.
4003 This can happen e.g. when the designated type is a record type,
4004 because their elaboration starts with an initial node from
4005 make_dummy_type, which may be the same node as the one we got.
4007 Besides, variants of this non-dummy type might have been created
4008 along the way. update_pointer_to is expected to properly take
4009 care of those situations. */
4011 {
4014 }
4015 else
4016 {
4019 = (is_from_limited_with
4025 }
4026 }
4027 }
4034 else
4035 {
4036 /* The run-time representation is the equivalent type. */
4039 }
4052 /* We treat this as identical to its base type; any constraint is
4053 meaningful only to the front-end.
4055 The designated type must be elaborated as well, if it does
4056 not have its own freeze node. Designated (sub)types created
4057 for constrained components of records with discriminants are
4058 not frozen by the front-end and thus not elaborated by gigi,
4059 because their use may appear before the base type is frozen,
4060 and because it is not clear that they are needed anywhere in
4061 gigi. With the current model, there is no correct place where
4062 they could be elaborated. */
4069 {
4070 /* If we are not defining this entity, and we have incomplete
4071 entities being processed above us, make a dummy type and
4072 elaborate it later. */
4074 {
4077 p->old_type
4082 }
4085 Incomplete_Or_Private_Kind))
4088 }
4093 /* Subprogram Entities
4095 The following access functions are defined for subprograms:
4097 Etype Return type or Standard_Void_Type.
4098 First_Formal The first formal parameter.
4099 Is_Imported Indicates that the subprogram has appeared in
4100 an INTERFACE or IMPORT pragma. For now we
4101 assume that the external language is C.
4102 Is_Exported Likewise but for an EXPORT pragma.
4103 Is_Inlined True if the subprogram is to be inlined.
4105 Each parameter is first checked by calling must_pass_by_ref on its
4106 type to determine if it is passed by reference. For parameters which
4107 are copied in, if they are Ada In Out or Out parameters, their return
4108 value becomes part of a record which becomes the return type of the
4109 function (C function - note that this applies only to Ada procedures
4110 so there is no Ada return type). Additional code to store back the
4111 parameters will be generated on the caller side. This transformation
4112 is done here, not in the front-end.
4114 The intended result of the transformation can be seen from the
4115 equivalent source rewritings that follow:
4117 struct temp {int a,b};
4118 procedure P (A,B: In Out ...) is temp P (int A,B)
4119 begin {
4120 .. ..
4121 end P; return {A,B};
4122 }
4124 temp t;
4125 P(X,Y); t = P(X,Y);
4126 X = t.a , Y = t.b;
4128 For subprogram types we need to perform mainly the same conversions to
4129 GCC form that are needed for procedures and function declarations. The
4130 only difference is that at the end, we make a type declaration instead
4131 of a function declaration. */
4136 {
4137 /* The type returned by a function or else Standard_Void_Type for a
4138 procedure. */
4140 tree gnu_return_type;
4141 /* The first GCC parameter declaration (a PARM_DECL node). The
4142 PARM_DECL nodes are chained through the DECL_CHAIN field, so this
4143 actually is the head of this parameter list. */
4145 /* Non-null for subprograms containing parameters passed by copy-in
4146 copy-out (Ada In Out or Out parameters not passed by reference),
4147 in which case it is the list of nodes used to specify the values
4148 of the In Out/Out parameters that are returned as a record upon
4149 procedure return. The TREE_PURPOSE of an element of this list is
4150 a field of the record and the TREE_VALUE is the PARM_DECL
4151 corresponding to that field. This list will be saved in the
4152 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
4154 /* List of fields in return type of procedure with copy-in copy-out
4155 parameters. */
4157 /* If an import pragma asks to map this subprogram to a GCC builtin,
4158 this is the builtin DECL node. */
4161 Entity_Id gnat_param;
4162 enum inline_status_t inline_status
4164 ? is_suppressed
4166 ? is_required
4169 /* Subprograms marked both Intrinsic and Always_Inline need not
4170 have a body of their own. */
4171 bool extern_flag
4173 || imported_p
4177 /* The semantics of "pure" in Ada essentially matches that of "const"
4178 in the back-end. In particular, both properties are orthogonal to
4179 the "nothrow" property if the EH circuitry is explicit in the
4180 internal representation of the back-end. If we are to completely
4181 hide the EH circuitry from it, we need to declare that calls to pure
4182 Ada subprograms that can throw have side effects since they can
4183 trigger an "abnormal" transfer of control flow; thus they can be
4184 neither "const" nor "pure" in the back-end sense. */
4185 bool const_flag
4194 /* A parameter may refer to this type, so defer completion of any
4195 incomplete types. */
4197 {
4198 defer_incomplete_level++;
4200 }
4202 /* If the subprogram has an alias, it is probably inherited, so
4203 we can use the original one. If the original "subprogram"
4204 is actually an enumeration literal, it may be the first use
4205 of its type, so we must elaborate that type now. */
4207 {
4213 /* Elaborate any Itypes in the parameters of this entity. */
4221 }
4223 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
4224 corresponding DECL node. Proper generation of calls later on need
4225 proper parameter associations so we don't "break;" here. */
4228 {
4231 /* Inability to find the builtin decl most often indicates a
4232 genuine mistake, but imports of unregistered intrinsics are
4233 sometimes issued on purpose to allow hooking in alternate
4234 bodies. We post a warning conditioned on Wshadow in this case,
4235 to let developers be notified on demand without risking false
4236 positives with common default sets of options. */
4240 }
4242 /* ??? What if we don't find the builtin node above ? warn ? err ?
4243 In the current state we neither warn nor err, and calls will just
4244 be handled as for regular subprograms. */
4246 /* Look into the return type and get its associated GCC tree. If it
4247 is not void, compute various flags for the subprogram type. */
4250 else
4251 {
4252 /* Ada 2012 (AI05-0151): Incomplete types coming from a limited
4253 context may now appear in parameter and result profiles. If
4254 we are only annotating types, break circularities here. */
4258 else
4261 /* If this function returns by reference, make the actual return
4262 type the pointer type and make a note of that. */
4264 {
4267 }
4269 /* If the return type is an unconstrained array type, the return
4270 value will be allocated on the secondary stack so the actual
4271 return type is the fat pointer type. */
4273 {
4276 }
4278 /* Likewise, if the return type requires a transient scope, the
4279 return value will also be allocated on the secondary stack so
4280 the actual return type is the pointer type. */
4282 {
4285 }
4287 /* If the Mechanism is By_Reference, ensure this function uses the
4288 target's by-invisible-reference mechanism, which may not be the
4289 same as above (e.g. it might be passing an extra parameter). */
4294 /* Likewise, if the return type is itself By_Reference. */
4298 /* If the type is a padded type and the underlying type would not
4299 be passed by reference or the function has a foreign convention,
4300 return the underlying type. */
4302 && (!default_pass_by_ref
4307 /* If the return type is unconstrained, that means it must have a
4308 maximum size. Use the padded type as the effective return type.
4309 And ensure the function uses the target's by-invisible-reference
4310 mechanism to avoid copying too much data when it returns. */
4312 {
4315 gnu_return_type
4321 /* Declare it now since it will never be declared otherwise.
4322 This is necessary to ensure that its subtrees are properly
4323 marked. */
4328 gnat_entity);
4331 }
4333 /* If the return type has a size that overflows, we cannot have
4334 a function that returns that type. This usage doesn't make
4335 sense anyway, so give an error here. */
4339 {
4341 gnat_entity);
4347 }
4348 }
4350 /* Loop over the parameters and get their associated GCC tree. While
4351 doing this, build a copy-in copy-out structure if we need one. */
4355 {
4362 /* Ada 2012 (AI05-0151): Incomplete types coming from a limited
4363 context may now appear in parameter and result profiles. If
4364 we are only annotating types, break circularities here. */
4367 {
4370 }
4371 else
4372 {
4375 }
4377 /* Builtins are expanded inline and there is no real call sequence
4378 involved. So the type expected by the underlying expander is
4379 always the type of each argument "as is". */
4382 /* Handle the first parameter of a valued procedure specially. */
4385 /* Otherwise, see if a Mechanism was supplied that forced this
4386 parameter to be passed one way or another. */
4390 ;
4392 {
4396 mech))
4398 else
4400 }
4401 else
4402 {
4405 }
4407 /* Do not call gnat_to_gnu_param for a fake parameter type since
4408 it will try to use the real type again. */
4410 {
4413 else
4414 {
4415 gnu_param
4422 }
4423 }
4424 else
4425 gnu_param
4430 /* We are returned either a PARM_DECL or a type if no parameter
4431 needs to be passed; in either case, adjust the type. */
4434 else
4435 {
4438 }
4440 /* The failure of this assertion will very likely come from an
4441 order of elaboration issue for the type of the parameter. */
4447 {
4453 /* If a parameter is a pointer, this function may modify
4454 memory through it and thus shouldn't be considered
4455 a const function. Also, the memory may be modified
4456 between two calls, so they can't be CSE'ed. The latter
4457 case also handles by-ref parameters. */
4461 }
4464 {
4466 {
4469 /* If this is a function, we also need a field for the
4470 return value to be placed. */
4472 {
4473 gnu_field
4475 gnu_return_type,
4481 gnu_cico_list
4483 }
4487 /* Set a default alignment to speed up accesses. But we
4488 shouldn't increase the size of the structure too much,
4489 lest it doesn't fit in return registers anymore. */
4492 }
4494 gnu_field
4502 gnu_cico_list
4504 }
4505 }
4508 {
4509 /* If we have a CICO list but it has only one entry, we convert
4510 this function into a function that returns this object. */
4514 /* Do not finalize the return type if the subprogram is stubbed
4515 since structures are incomplete for the back-end. */
4517 {
4521 /* Try to promote the mode of the return type if it is passed
4522 in registers, again to speed up accesses. */
4525 NULL_TREE))
4526 {
4527 unsigned int size
4530 machine_mode mode;
4536 {
4544 }
4545 }
4549 }
4550 }
4552 /* Deal with platform-specific calling conventions. */
4554 prepend_one_attribute
4557 gnat_entity);
4559 prepend_one_attribute
4562 gnat_entity);
4564 /* If we should request stack realignment for a foreign convention
4565 subprogram, do so. Note that this applies to task entry points
4566 in particular. */
4569 prepend_one_attribute
4572 gnat_entity);
4574 /* Deal with a pragma Linker_Section on a subprogram. */
4580 /* The lists have been built in reverse. */
4586 || return_by_direct_ref_p
4587 || return_by_invisi_ref_p
4589 gnu_type
4592 return_by_direct_ref_p,
4593 return_by_invisi_ref_p);
4595 /* A procedure (something that doesn't return anything) shouldn't be
4596 considered const since there would be no reason for calling such a
4597 subprogram. Note that procedures with Out (or In Out) parameters
4598 have already been converted into a function with a return type.
4599 Similarly, if the function returns an unconstrained type, then the
4600 function will allocate the return value on the secondary stack and
4601 thus calls to it cannot be CSE'ed, lest the stack be reclaimed. */
4606 {
4607 const int quals
4612 }
4614 /* If we have a builtin decl for that function, use it. Check if the
4615 profiles are compatible and warn if they are not. The checker is
4616 expected to post extra diagnostics in this case. */
4618 {
4619 intrin_binding_t inb;
4626 post_error
4628 gnat_entity);
4633 }
4635 /* If there was no specified Interface_Name and the external and
4636 internal names of the subprogram are the same, only use the
4637 internal name to allow disambiguation of nested subprograms. */
4642 /* If we are defining the subprogram and it has an Address clause
4643 we must get the address expression from the saved GCC tree for the
4644 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4645 the address expression here since the front-end has guaranteed
4646 in that case that the elaboration has no effects. If there is
4647 an Address clause and we are not defining the object, just
4648 make it a constant. */
4650 {
4654 gnu_address
4661 /* Convert the type of the object to a reference type that can
4662 alias everything as per 13.3(19). */
4663 gnu_type
4668 gnu_decl
4673 }
4676 {
4678 gnu_decl
4681 }
4682 else
4683 {
4684 gnu_decl
4689 /* This is unrelated to the stub built right above. */
4692 }
4693 }
4704 {
4705 /* Get the "full view" of this entity. If this is an incomplete
4706 entity from a limited with, treat its non-limited view as the
4707 full view. Otherwise, use either the full view or the underlying
4708 full view, whichever is present. This is used in all the tests
4709 below. */
4710 Entity_Id full_view
4719 /* If this is an incomplete type with no full view, it must be a Taft
4720 Amendment type, in which case we return a dummy type. Otherwise,
4721 just get the type from its Etype. */
4723 {
4725 {
4728 }
4729 else
4730 {
4734 }
4736 }
4738 /* If we already made a type for the full view, reuse it. */
4740 {
4743 }
4745 /* Otherwise, if we are not defining the type now, get the type
4746 from the full view. But always get the type from the full view
4747 for define on use types, since otherwise we won't see them! */
4751 {
4755 }
4757 /* For incomplete types, make a dummy type entry which will be
4758 replaced later. Save it as the full declaration's type so
4759 we can do any needed updates when we see it. */
4766 }
4769 /* Class-wide types are always transformed into their root type. */
4778 /* Concurrent types are always transformed into their record type. */
4781 else
4792 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4793 we've already saved it, so we don't try to. */
4799 /* This is a SPARK annotation that only reaches here when compiling in
4800 ASIS mode. */
4808 }
4810 /* If we had a case where we evaluated another type and it might have
4811 defined this one, handle it here. */
4813 {
4816 }
4818 /* If we are processing a type and there is either no decl for it or
4819 we just made one, do some common processing for the type, such as
4820 handling alignment and possible padding. */
4822 {
4823 /* Process the attributes, if not already done. Note that the type is
4824 already defined so we cannot pass true for IN_PLACE here. */
4827 /* Tell the middle-end that objects of tagged types are guaranteed to
4828 be properly aligned. This is necessary because conversions to the
4829 class-wide type are translated into conversions to the root type,
4830 which can be less aligned than some of its derived types. */
4835 /* Record whether the type is passed by reference. */
4839 /* ??? Don't set the size for a String_Literal since it is either
4840 confirming or we don't handle it properly (if the low bound is
4841 non-constant). */
4843 {
4846 gnu_size
4849 }
4851 /* If a size was specified, see if we can make a new type of that size
4852 by rearranging the type, for example from a fat to a thin pointer. */
4854 {
4855 gnu_type
4862 }
4864 /* If the alignment has not already been processed and this is not
4865 an unconstrained array type, see if an alignment is specified.
4866 If not, we pick a default alignment for atomic objects. */
4868 ;
4870 {
4874 /* Warn on suspiciously large alignments. This should catch
4875 errors about the (alignment,byte)/(size,bit) discrepancy. */
4877 {
4878 tree size;
4880 /* If a size was specified, take it into account. Otherwise
4881 use the RM size for records or unions as the type size has
4882 already been adjusted to the alignment. */
4888 else
4891 /* Consider an alignment as suspicious if the alignment/size
4892 ratio is greater or equal to the byte/bit ratio. */
4897 gnat_entity);
4898 }
4899 }
4910 /* See if we need to pad the type. If we did, and made a record,
4911 the name of the new type may be changed. So get it back for
4912 us when we make the new TYPE_DECL below. */
4920 /* Now set the RM size of the type. We cannot do it before padding
4921 because we need to accept arbitrary RM sizes on integral types. */
4924 /* If we are at global level, GCC will have applied variable_size to
4925 the type, but that won't have done anything. So, if it's not
4926 a constant or self-referential, call elaborate_expression_1 to
4927 make a variable for the size rather than calculating it each time.
4928 Handle both the RM size and the actual size. */
4933 {
4941 /* ??? For now, store the size as a multiple of the alignment in
4942 bytes so that we can see the alignment from the tree. */
4949 /* ??? gnu_type may come from an existing type so the MULT_EXPR node
4950 may not be marked by the call to create_type_decl below. */
4954 {
4959 {
4963 /* If the position of the variant part is constant, subtract
4964 it from the size of the type of the parent to get the new
4965 size. This manual CSE reduces the data size. */
4967 {
4975 }
4976 else
4977 {
4980 gnat_entity,
4984 /* ??? For now, store the size as a multiple of the
4985 alignment in bytes so that we can see the alignment
4986 from the tree. */
4989 gnat_entity,
4990 get_identifier
4995 /* ??? For now, store the offset as a multiple of the
4996 alignment in bytes so that we can see the alignment
4997 from the tree. */
5000 gnat_entity,
5003 DECL_OFFSET_ALIGN
5005 }
5009 }
5013 else
5014 ada_size
5019 }
5020 }
5022 /* If this is a record type or subtype, call elaborate_expression_2 on
5023 any field position. Do this for both global and local types.
5024 Skip any fields that we haven't made trees for to avoid problems with
5025 class wide types. */
5030 {
5033 /* ??? For now, store the offset as a multiple of the alignment
5034 in bytes so that we can see the alignment from the tree. */
5036 {
5039 gnat_temp,
5044 /* ??? The context of gnu_field is not necessarily gnu_type
5045 so the MULT_EXPR node built above may not be marked by
5046 the call to create_type_decl below. */
5049 }
5050 }
5055 /* If this is not an unconstrained array type, set some flags. */
5057 {
5066 }
5072 else
5073 {
5076 }
5077 }
5080 {
5083 /* If this is a derived type, relate its alias set to that of its parent
5084 to avoid troubles when a call to an inherited primitive is inlined in
5085 a context where a derived object is accessed. The inlined code works
5086 on the parent view so the resulting code may access the same object
5087 using both the parent and the derived alias sets, which thus have to
5088 conflict. As the same issue arises with component references, the
5089 parent alias set also has to conflict with composite types enclosing
5090 derived components. For instance, if we have:
5092 type D is new T;
5093 type R is record
5094 Component : D;
5095 end record;
5097 we want T to conflict with both D and R, in addition to R being a
5098 superset of D by record/component construction.
5100 One way to achieve this is to perform an alias set copy from the
5101 parent to the derived type. This is not quite appropriate, though,
5102 as we don't want separate derived types to conflict with each other:
5104 type I1 is new Integer;
5105 type I2 is new Integer;
5107 We want I1 and I2 to both conflict with Integer but we do not want
5108 I1 to conflict with I2, and an alias set copy on derivation would
5109 have that effect.
5111 The option chosen is to make the alias set of the derived type a
5112 superset of that of its parent type. It trivially fulfills the
5113 simple requirement for the Integer derivation example above, and
5114 the component case as well by superset transitivity:
5116 superset superset
5117 R ----------> D ----------> T
5119 However, for composite types, conversions between derived types are
5120 translated into VIEW_CONVERT_EXPRs so a sequence like:
5122 type Comp1 is new Comp;
5123 type Comp2 is new Comp;
5124 procedure Proc (C : Comp1);
5126 C : Comp2;
5127 Proc (Comp1 (C));
5129 is translated into:
5131 C : Comp2;
5132 Proc ((Comp1 &) &VIEW_CONVERT_EXPR <Comp1> (C));
5134 and gimplified into:
5136 C : Comp2;
5137 Comp1 *C.0;
5138 C.0 = (Comp1 *) &C;
5139 Proc (C.0);
5141 i.e. generates code involving type punning. Therefore, Comp1 needs
5142 to conflict with Comp2 and an alias set copy is required.
5144 The language rules ensure the parent type is already frozen here. */
5148 {
5150 /* For constrained packed array subtypes, the implementation type is
5151 used instead of the nominal type. */
5159 }
5161 /* Back-annotate the Alignment of the type if not already in the
5162 tree. Likewise for sizes. */
5164 {
5168 /* If the default alignment of "double" or larger scalar types is
5169 specifically capped and this is not an array with an alignment
5170 clause on the component type, return the cap. */
5172 is_capped_double
5175 is_capped_double
5177 else
5182 else
5186 }
5189 {
5192 /* If the size is self-referential, annotate the maximum value. */
5196 /* If we are just annotating types and the type is tagged, the tag
5197 and the parent components are not generated by the front-end so
5198 sizes must be adjusted if there is no representation clause. */
5204 {
5206 Uint uint_size;
5209 {
5213 }
5214 else
5218 offset
5226 }
5227 else
5229 }
5233 }
5235 /* If we really have a ..._DECL node, set a couple of flags on it. But we
5236 cannot do so if we are reusing the ..._DECL node made for an equivalent
5237 type or an alias or a renamed object as the predicates don't apply to it
5238 but to GNAT_ENTITY. */
5243 {
5249 }
5251 /* If we haven't already, associate the ..._DECL node that we just made with
5252 the input GNAT entity node. */
5256 /* Now we are sure gnat_entity has a corresponding ..._DECL node,
5257 eliminate as many deferred computations as possible. */
5260 /* If this is an enumeration or floating-point type, we were not able to set
5261 the bounds since they refer to the type. These are always static. */
5264 {
5268 /* If this is a padded type, we need to use the underlying type. */
5272 /* If this is a floating point type and we haven't set a floating
5273 point type yet, use this in the evaluation of the bounds. */
5281 {
5282 /* Enumeration types have specific RM bounds. */
5285 }
5286 else
5287 {
5288 /* Floating-point types don't have specific RM bounds. */
5291 }
5292 }
5294 /* If we deferred processing of incomplete types, re-enable it. If there
5295 were no other disables and we have deferred types to process, do so. */
5299 {
5302 /* We are back to level 0 for the deferring of incomplete types.
5303 But processing these incomplete types below may itself require
5304 deferring, so preserve what we have and restart from scratch. */
5309 {
5316 }
5317 }
5319 /* If we are not defining this type, see if it's on one of the lists of
5320 incomplete types. If so, handle the list entry now. */
5322 {
5327 {
5331 }
5335 {
5339 }
5340 }
5343 force_global--;
5345 /* If this is a packed array type whose original array type is itself
5346 an Itype without freeze node, make sure the latter is processed. */
5354 }
5356 /* Similar, but if the returned value is a COMPONENT_REF, return the
5357 FIELD_DECL. */
5359 tree
5361 {
5368 }
5370 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5371 the GCC type corresponding to that entity. */
5373 tree
5375 {
5376 tree gnu_decl;
5378 /* The back end never attempts to annotate generic types. */
5386 }
5388 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5389 the unpadded version of the GCC type corresponding to that entity. */
5391 tree
5393 {
5400 }
5402 /* Return the DECL associated with the public subprogram GNAT_ENTITY but whose
5403 type has been changed to that of the parameterless procedure, except if an
5404 alias is already present, in which case it is returned instead. */
5406 tree
5408 {
5412 /* See the E_Function/E_Procedure case of gnat_to_gnu_entity for the model
5413 of the handling applied here. */
5416 {
5420 }
5428 gnat_entity);
5432 gnat_entity);
5437 return
5440 }
5442 /* Return whether the E_Subprogram_Type/E_Function/E_Procedure GNAT_ENTITY is
5443 a C++ imported method or equivalent.
5445 We use the predicate on 32-bit x86/Windows to find out whether we need to
5446 use the "thiscall" calling convention for GNAT_ENTITY. This convention is
5447 used for C++ methods (functions with METHOD_TYPE) by the back-end. */
5449 bool
5451 {
5455 /* This is the main case: C++ method imported as a primitive operation.
5456 Note that a C++ class with no virtual functions can be imported as a
5457 limited record type so the operation is not necessarily dispatching. */
5461 /* A thunk needs to be handled like its associated primitive operation. */
5465 /* A constructor is a method on the C++ side. */
5469 /* This is set on the E_Subprogram_Type built for a dispatching call. */
5474 }
5476 /* Finalize the processing of From_Limited_With incomplete types. */
5478 void
5480 {
5487 {
5494 }
5495 }
5497 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
5498 kind of type (such E_Task_Type) that has a different type which Gigi
5499 uses for its representation. If the type does not have a special type
5500 for its representation, return GNAT_ENTITY. If a type is supposed to
5501 exist, but does not, abort unless annotating types, in which case
5502 return Empty. If GNAT_ENTITY is Empty, return Empty. */
5504 Entity_Id
5506 {
5513 {
5537 }
5542 }
5544 /* Return a GCC tree for a type corresponding to the component type of the
5545 array type or subtype GNAT_ARRAY. DEFINITION is true if this component
5546 is for an array being defined. DEBUG_INFO_P is true if we need to write
5547 debug information for other types that we may create in the process. */
5549 static tree
5552 {
5555 tree gnu_comp_size;
5557 /* Try to get a smaller form of the component if needed. */
5571 /* Get and validate any specified Component_Size. */
5572 gnu_comp_size
5577 /* If the array has aliased components and the component size can be zero,
5578 force at least unit size to ensure that the components have distinct
5579 addresses. */
5585 gnu_comp_size
5588 /* If the component type is a RECORD_TYPE that has a self-referential size,
5589 then use the maximum size for the component size. */
5595 /* Honor the component size. This is not needed for bit-packed arrays. */
5597 {
5601 /* If an alignment is specified, use it as a cap on the component type
5602 so that it can be honored for the whole type. But ignore it for the
5603 original type of packed array types. */
5607 else
5613 else
5619 /* If a padding record was made, declare it now since it will never be
5620 declared otherwise. This is necessary to ensure that its subtrees
5621 are properly marked. */
5624 gnat_array);
5625 }
5631 }
5633 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
5634 using MECH as its passing mechanism, to be placed in the parameter
5635 list built for GNAT_SUBPROG. Assume a foreign convention for the
5636 latter if FOREIGN is true. Also set CICO to true if the parameter
5637 must use the copy-in copy-out implementation mechanism.
5639 The returned tree is a PARM_DECL, except for those cases where no
5640 parameter needs to be actually passed to the subprogram; the type
5641 of this "shadow" parameter is then returned instead. */
5643 static tree
5646 {
5650 /* The parameter can be indirectly modified if its address is taken. */
5654 tree gnu_param;
5656 /* Copy-return is used only for the first parameter of a valued procedure.
5657 It's a copy mechanism for which a parameter is never allocated. */
5659 {
5663 }
5665 /* If this is either a foreign function or if the underlying type won't
5666 be passed by reference and is as aligned as the original type, strip
5667 off possible padding type. */
5669 {
5678 }
5680 /* If this is a read-only parameter, make a variant of the type that is
5681 read-only. ??? However, if this is an unconstrained array, that type
5682 can be very complex, so skip it for now. Likewise for any other
5683 self-referential type. */
5689 /* For foreign conventions, pass arrays as pointers to the element type.
5690 First check for unconstrained array and get the underlying array. */
5692 gnu_param_type
5695 /* For GCC builtins, pass Address integer types as (void *) */
5701 /* Arrays are passed as pointers to element type for foreign conventions. */
5703 {
5704 /* Strip off any multi-dimensional entries, then strip
5705 off the last array to get the component type. */
5714 gnu_param_type
5718 }
5720 /* Fat pointers are passed as thin pointers for foreign conventions. */
5722 gnu_param_type
5725 /* If we must pass or were requested to pass by reference, do so.
5726 If we were requested to pass by copy, do so.
5727 Otherwise, for foreign conventions, pass In Out or Out parameters
5728 or aggregates by reference. For COBOL and Fortran, pass all
5729 integer and FP types that way too. For Convention Ada, use
5730 the standard Ada default. */
5734 && ((foreign
5736 || (foreign
5741 || (!foreign
5743 {
5744 /* We take advantage of 6.2(12) by considering that references built for
5745 parameters whose type isn't by-ref and for which the mechanism hasn't
5746 been forced to by-ref are restrict-qualified in the C sense. */
5747 bool restrict_p
5751 gnu_param_type
5754 }
5756 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
5763 /* If this is an Out parameter that isn't passed by reference and isn't
5764 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
5765 it will be a VAR_DECL created when we process the procedure, so just
5766 return its type. For the special parameter of a valued procedure,
5767 never pass it in.
5769 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
5770 Out parameters with discriminants or implicit initial values to be
5771 handled like In Out parameters. These type are normally built as
5772 aggregates, hence passed by reference, except for some packed arrays
5773 which end up encoded in special integer types. Note that scalars can
5774 be given implicit initial values using the Default_Value aspect.
5776 The exception we need to make is then for packed arrays of records
5777 with discriminants or implicit initial values. We have no light/easy
5778 way to check for the latter case, so we merely check for packed arrays
5779 of records. This may lead to useless copy-in operations, but in very
5780 rare cases only, as these would be exceptions in a set of already
5781 exceptional situations. */
5783 && !by_ref
5784 && (by_return
5801 /* If no Mechanism was specified, indicate what we're using, then
5802 back-annotate it. */
5808 }
5810 /* Return true if GNAT_ENTITY is an incomplete entity coming from a limited
5811 with of the main unit and whose full view has not been elaborated yet. */
5813 static bool
5815 {
5816 /* Class-wide types are always transformed into their root type. */
5822 {
5829 }
5832 }
5834 /* Like build_qualified_type, but TYPE_QUALS is added to the existing
5835 qualifiers on TYPE. */
5837 static tree
5839 {
5841 }
5843 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
5845 static bool
5847 {
5854 return
5856 }
5858 /* Return true if the array type GNU_TYPE, which represents a dimension of
5859 GNAT_TYPE, has a non-aliased component in the back-end sense. */
5861 static bool
5863 {
5864 /* If the array type is not the innermost dimension of the GNAT type,
5865 then it has a non-aliased component. */
5870 /* If the array type has an aliased component in the front-end sense,
5871 then it also has an aliased component in the back-end sense. */
5875 /* If this is a derived type, then it has a non-aliased component if
5876 and only if its parent type also has one. */
5878 {
5882 gnu_parent_type
5887 }
5889 /* Otherwise, rely exclusively on properties of the element type. */
5891 }
5893 /* Return true if GNAT_ADDRESS is a value known at compile-time. */
5895 static bool
5897 {
5898 /* Catch System'To_Address. */
5903 }
5905 /* Return true if GNAT_RANGE, a N_Range node, cannot be superflat, i.e. if the
5906 inequality HB >= LB-1 is true. LB and HB are the low and high bounds. */
5908 static bool
5910 {
5912 Node_Id scalar_range;
5915 /* If the low bound is not constant, try to find an upper bound. */
5924 /* If the high bound is not constant, try to find a lower bound. */
5933 /* If we have failed to find constant bounds, punt. */
5938 /* We need at least a signed 64-bit type to catch most cases. */
5944 /* If the low bound is the smallest integer, nothing can be smaller. */
5950 }
5952 /* Return true if GNU_EXPR is (essentially) the address of a CONSTRUCTOR. */
5954 static bool
5956 {
5964 }
5965 \f
5966 /* Given GNAT_ENTITY, elaborate all expressions that are required to
5967 be elaborated at the point of its definition, but do nothing else. */
5969 void
5971 {
5973 {
5980 {
5984 /* ??? Tests to avoid Constraint_Error in static expressions
5985 are needed until after the front stops generating bogus
5986 conversions on bounds of real types. */
5994 }
6001 {
6002 Node_Id gnat_discriminant_expr;
6003 Entity_Id gnat_field;
6007 gnat_discriminant_expr
6012 /* Ignore access discriminants. */
6017 }
6020 }
6021 }
6022 \f
6023 /* Return true if the size in units represented by GNU_SIZE can be handled by
6024 an allocation. If STATIC_P is true, consider only what can be done with a
6025 static allocation. */
6027 static bool
6029 {
6030 /* We can allocate a fixed size if it is a valid for the middle-end. */
6034 /* We can allocate a variable size if this isn't a static allocation. */
6035 else
6037 }
6038 \f
6039 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
6040 NAME, ARGS and ERROR_POINT. */
6042 static void
6045 tree attr_name,
6046 tree attr_args,
6047 Node_Id attr_error_point)
6048 {
6058 }
6060 /* Prepend to ATTR_LIST an entry for an attribute provided by GNAT_PRAGMA. */
6062 static void
6064 {
6069 /* Map the pragma at hand. Skip if this isn't one we know how to handle. */
6071 {
6102 }
6104 /* See what arguments we have and turn them into GCC trees for attribute
6105 handlers. These expect identifier for strings. We handle at most two
6106 arguments and static expressions only. */
6108 {
6114 {
6118 {
6122 }
6125 }
6129 {
6134 }
6135 }
6137 /* Prepend to the list. Make a list of the argument we might have, as GCC
6138 expects it. */
6140 gnu_arg1
6144 }
6146 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
6148 static void
6150 {
6151 Node_Id gnat_temp;
6153 /* Attributes are stored as Representation Item pragmas. */
6159 }
6160 \f
6161 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
6162 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
6163 return the GCC tree to use for that expression. GNU_NAME is the suffix
6164 to use if a variable needs to be created and DEFINITION is true if this
6165 is a definition of GNAT_ENTITY. If NEED_VALUE is true, we need a result;
6166 otherwise, we are just elaborating the expression for side-effects. If
6167 NEED_DEBUG is true, we need a variable for debugging purposes even if it
6168 isn't needed for code generation. */
6170 static tree
6173 {
6174 tree gnu_expr;
6176 /* If we already elaborated this expression (e.g. it was involved
6177 in the definition of a private type), use the old value. */
6181 /* If we don't need a value and this is static or a discriminant,
6182 we don't need to do anything. */
6189 /* If it's a static expression, we don't need a variable for debugging. */
6193 /* Otherwise, convert this tree to its GCC equivalent and elaborate it. */
6197 /* Save the expression in case we try to elaborate this entity again. Since
6198 it's not a DECL, don't check it. Don't save if it's a discriminant. */
6203 }
6205 /* Similar, but take a GNU expression and always return a result. */
6207 static tree
6210 {
6215 /* In most cases, we won't see a naked FIELD_DECL because a discriminant
6216 reference will have been replaced with a COMPONENT_REF when the type
6217 is being elaborated. However, there are some cases involving child
6218 types where we will. So convert it to a COMPONENT_REF. We hope it
6219 will be at the highest level of the expression in these cases. */
6225 /* If GNU_EXPR contains a placeholder, just return it. We rely on the fact
6226 that an expression cannot contain both a discriminant and a variable. */
6230 /* If GNU_EXPR is neither a constant nor based on a read-only variable, make
6231 a variable that is initialized to contain the expression when the package
6232 containing the definition is elaborated. If this entity is defined at top
6233 level, replace the expression by the variable; otherwise use a SAVE_EXPR
6234 if this is necessary. */
6237 else
6238 {
6239 /* Skip any conversions and simple constant arithmetics to see if the
6240 expression is based on a read-only variable.
6241 ??? This really should remain read-only, but we have to think about
6242 the typing of the tree here. */
6248 {
6250 tree offset;
6251 machine_mode mode;
6256 /* If the offset is variable, err on the side of caution. */
6259 }
6261 expr_variable_p
6262 = !(inner
6265 }
6267 /* We only need to use the variable if we are in a global context since GCC
6268 can do the right thing in the local case. However, when not optimizing,
6269 use it for bounds of loop iteration scheme to avoid code duplication. */
6270 use_variable = expr_variable_p
6271 && (expr_global_p
6272 || (!optimize
6273 && definition
6278 /* Now create it, possibly only for debugging purposes. */
6280 {
6281 /* The following variable creation can happen when processing the body of
6282 subprograms that are defined out of the extended main unit and
6283 inlined. In this case, we are not at the global scope, and thus the
6284 new variable must not be tagged "external", as we used to do here as
6285 long as definition == 0. */
6287 tree gnu_decl
6288 = create_var_decl_1
6295 /* Using this variable at debug time (if need_debug is true) requires a
6296 proper location. The back-end will compute a location for this
6297 variable only if the variable is used by the generated code.
6298 Returning the variable ensures the caller will use it in generated
6299 code. Note that there is no need for a location if the debug info
6300 contains an integer constant.
6301 FIXME: when the encoding-based debug scheme is dropped, move this
6302 condition to the top-level IF block: we will not need to create a
6303 variable anymore in such cases, then. */
6306 }
6309 }
6311 /* Similar, but take an alignment factor and make it explicit in the tree. */
6313 static tree
6316 {
6318 return
6321 gnu_expr,
6322 unit_align),
6324 need_debug),
6325 unit_align);
6326 }
6327 \f
6328 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
6329 the value passed against the list of choices. */
6331 tree
6333 {
6334 Node_Id choice;
6335 Node_Id gnat_temp;
6340 {
6342 {
6347 this_test
6361 this_test
6371 /* This represents either a subtype range, an enumeration
6372 literal, or a constant Ekind says which. If an enumeration
6373 literal or constant, fall through to the next case. */
6376 {
6382 this_test
6389 }
6391 /* ... fall through ... */
6397 single);
6406 }
6409 this_test);
6410 }
6413 }
6414 \f
6415 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
6416 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
6418 static int
6420 {
6421 /* If the field contains an item of variable size, we cannot pack it
6422 because we cannot create temporaries of non-fixed size in case
6423 we need to take the address of the field. See addressable_p and
6424 the notes on the addressability issues for further details. */
6428 /* If the alignment of the record is specified and the field type
6429 is over-aligned, request Storage_Unit alignment for the field. */
6431 {
6434 else
6436 }
6439 }
6441 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
6442 placed in GNU_RECORD_TYPE.
6444 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
6445 record has Component_Alignment of Storage_Unit, -2 if the enclosing
6446 record has a specified alignment.
6448 DEFINITION is true if this field is for a record being defined.
6450 DEBUG_INFO_P is true if we need to write debug information for types
6451 that we may create in the process. */
6453 static tree
6456 {
6458 const bool is_aliased
6460 const bool is_atomic
6462 const bool is_independent
6464 const bool is_volatile
6466 const bool needs_strict_alignment
6467 = (is_aliased
6468 || is_independent
6469 || is_volatile
6475 /* If this field requires strict alignment, we cannot pack it because
6476 it would very likely be under-aligned in the record. */
6479 else
6482 /* If a size is specified, use it. Otherwise, if the record type is packed,
6483 use the official RM size. See "Handling of Type'Size Values" in Einfo
6484 for further details. */
6491 else
6494 /* If we have a specified size that is smaller than that of the field's type,
6495 or a position is specified, and the field's type is a record that doesn't
6496 require strict alignment, see if we can get either an integral mode form
6497 of the type or a smaller form. If we can, show a size was specified for
6498 the field if there wasn't one already, so we know to make this a bitfield
6499 and avoid making things wider.
6501 Changing to an integral mode form is useful when the record is packed as
6502 we can then place the field at a non-byte-aligned position and so achieve
6503 tighter packing. This is in addition required if the field shares a byte
6504 with another field and the front-end lets the back-end handle the access
6505 to the field, because GCC cannot handle non-byte-aligned BLKmode fields.
6507 Changing to a smaller form is required if the specified size is smaller
6508 than that of the field's type and the type contains sub-fields that are
6509 padded, in order to avoid generating accesses to these sub-fields that
6510 are wider than the field.
6512 We avoid the transformation if it is not required or potentially useful,
6513 as it might entail an increase of the field's alignment and have ripple
6514 effects on the outer record type. A typical case is a field known to be
6515 byte-aligned and not to share a byte with another field. */
6521 || (gnu_size
6527 {
6530 {
6534 }
6535 }
6541 {
6543 Entity_Id gnat_parent
6550 /* Ensure the position does not overlap with the parent subtype, if there
6551 is one. This test is omitted if the parent of the tagged type has a
6552 full rep clause since, in this case, component clauses are allowed to
6553 overlay the space allocated for the parent type and the front-end has
6554 checked that there are no overlapping components. */
6556 {
6561 post_error_ne_tree
6564 }
6566 /* If this field needs strict alignment, make sure that the record is
6567 sufficiently aligned and that the position and size are consistent
6568 with the type. But don't do it if we are just annotating types and
6569 the field's type is tagged, since tagged types aren't fully laid out
6570 in this mode. Also, note that atomic implies volatile so the inner
6571 test sequences ordering is significant here. */
6574 {
6580 /* If the position is not a multiple of the alignment of the type,
6581 then error out and reset the position. */
6584 {
6598 else
6602 type_align);
6604 }
6607 {
6611 /* If the size is lower than that of the type, or greater for
6612 atomic and aliased, then error out and reset the size. */
6614 {
6628 else
6632 gnu_type_size);
6634 }
6636 /* Likewise if the size is not a multiple of a byte, */
6638 bitsize_unit_node)))
6639 {
6651 else
6656 }
6657 }
6658 }
6659 }
6661 /* If the record has rep clauses and this is the tag field, make a rep
6662 clause for it as well. */
6665 {
6668 }
6670 else
6671 {
6674 /* If we are packing the record and the field is BLKmode, round the
6675 size up to a byte boundary. */
6678 }
6680 /* We need to make the size the maximum for the type if it is
6681 self-referential and an unconstrained type. In that case, we can't
6682 pack the field since we can't make a copy to align it. */
6684 && !gnu_size
6687 {
6690 }
6692 /* If a size is specified, adjust the field's type to it. */
6694 {
6695 tree orig_field_type;
6697 /* If the field's type is justified modular, we would need to remove
6698 the wrapper to (better) meet the layout requirements. However we
6699 can do so only if the field is not aliased to preserve the unique
6700 layout and if the prescribed size is not greater than that of the
6701 packed array to preserve the justification. */
6709 /* Similarly if the field's type is a misaligned integral type, but
6710 there is no restriction on the size as there is no justification. */
6716 gnu_field_type
6724 /* If a padding record was made, declare it now since it will never be
6725 declared otherwise. This is necessary to ensure that its subtrees
6726 are properly marked. */
6731 }
6733 /* Otherwise (or if there was an error), don't specify a position. */
6734 else
6740 /* Now create the decl for the field. */
6741 gnu_field
6753 }
6754 \f
6755 /* Return true if at least one member of COMPONENT_LIST needs strict
6756 alignment. */
6758 static bool
6760 {
6761 Node_Id component_decl;
6766 {
6774 }
6777 }
6779 /* Return true if TYPE is a type with variable size or a padding type with a
6780 field of variable size or a record that has a field with such a type. */
6782 static bool
6784 {
6785 tree field;
6802 }
6803 \f
6804 /* Return true if FIELD is an artificial field. */
6806 static bool
6808 {
6809 /* These fields are generated by the front-end proper. */
6813 /* These fields are generated by gigi. */
6818 }
6820 /* Return true if FIELD is a non-artificial aliased field. */
6822 static bool
6824 {
6829 }
6831 /* Return true if FIELD is a non-artificial field with self-referential
6832 size. */
6834 static bool
6836 {
6844 }
6846 /* Return true if FIELD is a non-artificial field with variable size. */
6848 static bool
6850 {
6858 }
6860 /* qsort comparer for the bit positions of two record components. */
6862 static int
6864 {
6867 const int ret
6871 }
6873 /* Structure holding information for a given variant. */
6875 {
6876 /* The record type of the variant. */
6877 tree type;
6879 /* The name of the variant. */
6880 tree name;
6882 /* The qualifier of the variant. */
6883 tree qual;
6885 /* Whether the variant has a rep clause. */
6888 /* Whether the variant is packed. */
6893 /* Translate and chain the GNAT_COMPONENT_LIST to the GNU_FIELD_LIST, set the
6894 result as the field list of GNU_RECORD_TYPE and finish it up. Return true
6895 if GNU_RECORD_TYPE has a rep clause which affects the layout (see below).
6896 When called from gnat_to_gnu_entity during the processing of a record type
6897 definition, the GCC node for the parent, if any, will be the single field
6898 of GNU_RECORD_TYPE and the GCC nodes for the discriminants will be on the
6899 GNU_FIELD_LIST. The other calls to this function are recursive calls for
6900 the component list of a variant and, in this case, GNU_FIELD_LIST is empty.
6902 PACKED is 1 if this is for a packed record, -1 if this is for a record
6903 with Component_Alignment of Storage_Unit, -2 if this is for a record
6904 with a specified alignment.
6906 DEFINITION is true if we are defining this record type.
6908 CANCEL_ALIGNMENT is true if the alignment should be zeroed before laying
6909 out the record. This means the alignment only serves to force fields to
6910 be bitfields, but not to require the record to be that aligned. This is
6911 used for variants.
6913 ALL_REP is true if a rep clause is present for all the fields.
6915 UNCHECKED_UNION is true if we are building this type for a record with a
6916 Pragma Unchecked_Union.
6918 ARTIFICIAL is true if this is a type that was generated by the compiler.
6920 DEBUG_INFO is true if we need to write debug information about the type.
6922 MAYBE_UNUSED is true if this type may be unused in the end; this doesn't
6923 mean that its contents may be unused as well, only the container itself.
6925 REORDER is true if we are permitted to reorder components of this type.
6927 FIRST_FREE_POS, if nonzero, is the first (lowest) free field position in
6928 the outer record type down to this variant level. It is nonzero only if
6929 all the fields down to this level have a rep clause and ALL_REP is false.
6931 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
6932 with a rep clause is to be added; in this case, that is all that should
6933 be done with such fields and the return value will be false. */
6935 static bool
6942 {
6956 /* For each component referenced in a component declaration create a GCC
6957 field and add it to the list, skipping pragmas in the GNAT list. */
6964 {
6968 /* If present, the _Parent field must have been created as the single
6969 field of the record type. Put it before any other fields. */
6971 {
6974 }
6975 else
6976 {
6980 /* If this is the _Tag field, put it before any other fields. */
6984 /* If this is the _Controller field, put it before the other
6985 fields except for the _Tag or _Parent field. */
6987 {
6990 }
6992 /* If this is a regular field, put it after the other fields. */
6993 else
6994 {
7000 /* And record information for the final layout. */
7005 }
7006 }
7009 }
7011 /* At the end of the component list there may be a variant part. */
7014 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
7015 mutually exclusive and should go in the same memory. To do this we need
7016 to treat each variant as a record whose elements are created from the
7017 component list for the variant. So here we create the records from the
7018 lists for the variants and put them all into the QUAL_UNION_TYPE.
7019 If this is an Unchecked_Union, we make a UNION_TYPE instead or
7020 use GNU_RECORD_TYPE if there are no fields so far. */
7022 {
7026 tree gnu_var_name
7037 gnu_union_name
7040 /* Reuse the enclosing union if this is an Unchecked_Union whose fields
7041 are all in the variant part, to match the layout of C unions. There
7042 is an associated check below. */
7045 else
7046 {
7047 gnu_union_type
7053 }
7055 /* If all the fields down to this level have a rep clause, find out
7056 whether all the fields at this level also have one. If so, then
7057 compute the new first free position to be passed downward. */
7060 {
7062 gnu_field;
7065 {
7068 this_first_free_pos
7070 }
7071 else
7072 {
7075 }
7076 }
7078 /* We build the variants in two passes. The bulk of the work is done in
7079 the first pass, that is to say translating the GNAT nodes, building
7080 the container types and computing the associated properties. However
7081 we cannot finish up the container types during this pass because we
7082 don't know where the variant part will be placed until the end. */
7086 {
7091 vinfo_t vinfo;
7099 /* Set the alignment of the inner type in case we need to make
7100 inner objects into bitfields, but then clear it out so the
7101 record actually gets only the alignment required. */
7105 /* Similarly, if the outer record has a size specified and all
7106 the fields have a rep clause, we can propagate the size. */
7108 {
7112 }
7114 /* Add the fields into the record type for the variant. Note that
7115 we aren't sure to really use it at this point, see below. */
7116 has_rep
7120 unchecked_union,
7122 this_first_free_pos,
7123 all_rep || this_first_free_pos
7126 /* Translate the qualifier and annotate the GNAT node. */
7130 /* Deal with packedness like in gnat_to_gnu_field. */
7132 {
7135 }
7136 else
7137 field_packed
7140 /* Push this variant onto the stack for the second pass. */
7148 /* Compute the global properties that will determine the placement of
7149 the variant part. */
7153 }
7155 /* Round up the first free position to the alignment of the variant part
7156 for the variants without rep clause. This will guarantee a consistent
7157 layout independently of the placement of the variant part. */
7161 /* In the second pass, the container types are adjusted if necessary and
7162 finished up, then the corresponding fields of the variant part are
7163 built with their qualifier, unless this is an unchecked union. */
7165 {
7169 /* If this is an Unchecked_Union whose fields are all in the variant
7170 part and we have a single field with no representation clause or
7171 placed at offset zero, use the field directly to match the layout
7172 of C unions. */
7174 && gnu_field_list
7178 {
7181 }
7182 else
7183 {
7184 /* Finalize the variant type now. We used to throw away empty
7185 record types but we no longer do that because we need them to
7186 generate complete debug info for the variant; otherwise, the
7187 union type definition will be lacking the fields associated
7188 with these empty variants. */
7190 {
7191 /* The variant part will be at offset 0 so we need to ensure
7192 that the fields are laid out starting from the first free
7193 position at this level. */
7195 tree gnu_rep_part;
7197 gnu_rep_part
7199 this_first_free_pos);
7204 }
7211 gnu_field
7213 gnu_union_type,
7214 all_rep_and_size
7223 }
7227 }
7229 /* Only make the QUAL_UNION_TYPE if there are non-empty variants. */
7231 {
7235 {
7239 }
7244 /* If GNU_UNION_TYPE is our record type, it means we must have an
7245 Unchecked_Union with no fields. Verify that and, if so, just
7246 return. */
7248 {
7250 && !gnu_field_list
7253 }
7258 /* Deal with packedness like in gnat_to_gnu_field. */
7261 else
7262 union_field_packed
7265 gnu_variant_part
7267 all_rep_and_size
7273 }
7274 }
7276 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses and, if we are
7277 permitted to reorder components, self-referential sizes or variable sizes.
7278 If they do, pull them out and put them onto the appropriate list. We have
7279 to do this in a separate pass since we want to handle the discriminants
7280 but can't play with them until we've used them in debugging data above.
7282 Similarly, pull out the fields with zero size and no rep clause, as they
7283 would otherwise modify the layout and thus very likely run afoul of the
7284 Ada semantics, which are different from those of C here.
7286 ??? If we reorder them, debugging information will be wrong but there is
7287 nothing that can be done about this at the moment. */
7290 #define MOVE_FROM_FIELD_LIST_TO(LIST) \
7291 do { \
7292 if (gnu_last) \
7293 DECL_CHAIN (gnu_last) = gnu_next; \
7294 else \
7295 gnu_field_list = gnu_next; \
7296 \
7297 DECL_CHAIN (gnu_field) = (LIST); \
7298 (LIST) = gnu_field; \
7299 } while (0)
7302 {
7306 {
7309 }
7313 {
7316 }
7319 {
7322 }
7325 {
7335 }
7338 }
7340 #undef MOVE_FROM_FIELD_LIST_TO
7344 /* If permitted, we reorder the fields as follows:
7346 1) all fixed length fields,
7347 2) all fields whose length doesn't depend on discriminants,
7348 3) all fields whose length depends on discriminants,
7349 4) the variant part,
7351 within the record and within each variant recursively. */
7353 gnu_field_list
7356 /* Otherwise, if there is an aliased field placed after a field whose length
7357 depends on discriminants, we put all the fields of the latter sort, last.
7358 We need to do this in case an object of this record type is mutable. */
7362 /* If P_REP_LIST is nonzero, this means that we are asked to move the fields
7363 in our REP list to the previous level because this level needs them in
7364 order to do a correct layout, i.e. avoid having overlapping fields. */
7368 /* Otherwise, sort the fields by bit position and put them into their own
7369 record, before the others, if we also have fields without rep clause. */
7371 {
7376 /* If all the fields have a rep clause, we can do a flat layout. */
7377 layout_with_rep = !gnu_field_list
7379 gnu_rep_type
7383 gnu_field;
7389 /* Put the fields in the list in order of increasing position, which
7390 means we start from the end. */
7393 {
7397 }
7401 else
7402 {
7405 /* If FIRST_FREE_POS is nonzero, we need to ensure that the fields
7406 without rep clause are laid out starting from this position.
7407 Therefore, we force it as a minimal size on the REP part. */
7408 gnu_rep_part
7411 /* Chain the REP part at the beginning of the field list. */
7414 }
7415 }
7417 /* Chain the variant part at the end of the field list. */
7429 /* Chain the fields with zero size at the beginning of the field list. */
7435 }
7436 \f
7437 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
7438 placed into an Esize, Component_Bit_Offset, or Component_Size value
7439 in the GNAT tree. */
7441 static Uint
7443 {
7444 TCode tcode;
7449 /* See if we've already saved the value for this node. */
7451 {
7459 }
7460 else
7463 /* If we do not return inside this switch, TCODE will be set to the
7464 code to use for a Create_Node operand and LEN (set above) will be
7465 the number of recursive calls for us to make. */
7468 {
7473 /* The only case we handle here is a simple discriminant reference. */
7475 {
7478 /* Climb up the chain of successive extensions, if any. */
7485 return
7487 }
7494 /* Now just list the operations we handle. */
7525 /* For negative values in sizetype, build NEGATE_EXPR of the opposite.
7526 Such values appear in expressions with aligning patterns. Note that,
7527 since sizetype is unsigned, we have to jump through some hoops. */
7529 {
7533 {
7536 }
7537 }
7541 /* In regular mode, inline back only if symbolic annotation is requested
7542 in order to avoid memory explosion on big discriminated record types.
7543 But not in ASIS mode, as symbolic annotation is required for DDA. */
7545 {
7549 }
7550 else
7553 /* Fall through... */
7557 }
7559 /* Now get each of the operands that's relevant for this code. If any
7560 cannot be expressed as a repinfo node, say we can't. */
7565 {
7568 else
7572 }
7576 /* Save the result in the cache. */
7578 {
7580 /* We can't assume the hash table data hasn't moved since the initial
7581 look up, so we have to search again. Allocating and inserting an
7582 entry at that point would be an alternative, but then we'd better
7583 discard the entry if we decided not to cache it. */
7589 }
7592 }
7594 /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
7595 and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
7596 size and alignment used by Gigi. Prefer SIZE over TYPE_SIZE if non-null.
7597 BY_REF is true if the object is used by reference. */
7599 void
7601 {
7603 {
7606 else
7608 }
7611 {
7620 }
7625 }
7627 /* Return first element of field list whose TREE_PURPOSE is the same as ELEM.
7628 Return NULL_TREE if there is no such element in the list. */
7630 static tree
7632 {
7634 {
7639 }
7641 }
7643 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding GCC type,
7644 set Component_Bit_Offset and Esize of the components to the position and
7645 size used by Gigi. */
7647 static void
7649 {
7650 Entity_Id gnat_field;
7651 tree gnu_list;
7653 /* We operate by first making a list of all fields and their position (we
7654 can get the size easily) and then update all the sizes in the tree. */
7655 gnu_list
7665 {
7667 gnu_list);
7669 {
7670 tree parent_offset;
7672 /* If we are just annotating types and the type is tagged, the tag
7673 and the parent components are not generated by the front-end so
7674 we need to add the appropriate offset to each component without
7675 representation clause. */
7679 {
7680 /* For a component appearing in the current extension, the
7681 offset is the size of the parent. */
7684 parent_offset
7686 bitsizetype);
7687 else
7691 parent_offset
7694 }
7695 else
7698 Set_Component_Bit_Offset
7700 annotate_value
7704 parent_offset)));
7708 }
7710 {
7711 /* If there is no entry, this is an inherited component whose
7712 position is the same as in the parent type. */
7713 Set_Component_Bit_Offset
7719 }
7720 }
7721 }
7722 \f
7723 /* Scan all fields in GNU_TYPE and return a TREE_LIST where TREE_PURPOSE is
7724 the FIELD_DECL and TREE_VALUE a TREE_VEC containing the byte position, the
7725 value to be placed into DECL_OFFSET_ALIGN and the bit position. The list
7726 of fields is flattened, except for variant parts if DO_NOT_FLATTEN_VARIANT
7727 is set to true. GNU_POS is to be added to the position, GNU_BITPOS to the
7728 bit position, OFFSET_ALIGN is the present offset alignment. GNU_LIST is a
7729 pre-existing list to be chained to the newly created entries. */
7731 static tree
7734 {
7735 tree gnu_field;
7738 gnu_field;
7740 {
7745 unsigned int our_offset_align
7754 /* Recurse on internal fields, flattening the nested fields except for
7755 those in the variant part, if requested. */
7757 {
7761 gnu_list
7765 else
7766 gnu_list
7770 }
7771 }
7774 }
7776 /* Return a list describing the substitutions needed to reflect the
7777 discriminant substitutions from GNAT_TYPE to GNAT_SUBTYPE. They can
7778 be in any order. The values in an element of the list are in the form
7779 of operands to SUBSTITUTE_IN_EXPR. DEFINITION is true if this is for
7780 a definition of GNAT_SUBTYPE. */
7784 {
7786 Entity_Id gnat_discrim;
7787 Node_Id gnat_constr;
7794 /* Ignore access discriminants. */
7796 {
7799 elaborate_expression
7805 }
7808 }
7810 /* Scan all fields in QUAL_UNION_TYPE and return a list describing the
7811 variants of QUAL_UNION_TYPE that are still relevant after applying
7812 the substitutions described in SUBST_LIST. GNU_LIST is a pre-existing
7813 list to be prepended to the newly created entries. */
7818 {
7819 tree gnu_field;
7822 gnu_field;
7824 {
7832 /* If the new qualifier is not unconditionally false, its variant may
7833 still be accessed. */
7835 {
7841 /* Recurse on the variant subpart of the variant, if any. */
7847 /* If the new qualifier is unconditionally true, the subsequent
7848 variants cannot be accessed. */
7851 }
7852 }
7855 }
7856 \f
7857 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
7858 corresponding to GNAT_OBJECT. If the size is valid, return an INTEGER_CST
7859 corresponding to its value. Otherwise, return NULL_TREE. KIND is set to
7860 VAR_DECL if we are specifying the size of an object, TYPE_DECL for the
7861 size of a type, and FIELD_DECL for the size of a field. COMPONENT_P is
7862 true if we are being called to process the Component_Size of GNAT_OBJECT;
7863 this is used only for error messages. ZERO_OK is true if a size of zero
7864 is permitted; if ZERO_OK is false, it means that a size of zero should be
7865 treated as an unspecified size. */
7867 static tree
7870 {
7871 Node_Id gnat_error_node;
7874 /* Return 0 if no size was specified. */
7878 /* Ignore a negative size since that corresponds to our back-annotation. */
7882 /* Find the node to use for error messages. */
7889 else
7892 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
7893 but cannot be represented in bitsizetype. */
7896 {
7899 gnat_object);
7900 else
7902 gnat_object);
7904 }
7906 /* Ignore a zero size if it is not permitted. */
7910 /* The size of objects is always a multiple of a byte. */
7913 {
7917 else
7921 }
7923 /* If this is an integral type or a packed array type, the front-end has
7924 already verified the size, so we need not do it here (which would mean
7925 checking against the bounds). However, if this is an aliased object,
7926 it may not be smaller than the type of the object. */
7931 /* If the object is a record that contains a template, add the size of the
7932 template to the specified size. */
7938 /* If a type needs strict alignment, a component of this type in
7939 a packed record cannot be packed and thus uses the type size. */
7942 else
7945 /* Modify the size of a discriminated type to be the maximum size. */
7949 /* If this is an access type or a fat pointer, the minimum size is that given
7950 by the smallest integral mode that's valid for pointers. */
7952 {
7957 }
7959 /* Issue an error either if the default size of the object isn't a constant
7960 or if the new size is smaller than it. */
7964 {
7966 post_error_ne_tree
7969 else
7970 post_error_ne_tree
7974 }
7977 }
7978 \f
7979 /* Similarly, but both validate and process a value of RM size. This routine
7980 is only called for types. */
7982 static void
7984 {
7985 Node_Id gnat_attr_node;
7988 /* Do nothing if no size was specified. */
7992 /* Ignore a negative size since that corresponds to our back-annotation. */
7996 /* Only issue an error if a Value_Size clause was explicitly given.
7997 Otherwise, we'd be duplicating an error on the Size clause. */
7998 gnat_attr_node
8001 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
8002 but cannot be represented in bitsizetype. */
8005 {
8008 gnat_entity);
8010 }
8012 /* Ignore a zero size unless a Value_Size clause exists, or a size clause
8013 exists, or this is an integer type, in which case the front-end will
8014 have always set it. */
8023 /* If the old size is self-referential, get the maximum size. */
8027 /* Issue an error either if the old size of the object isn't a constant or
8028 if the new size is smaller than it. The front-end has already verified
8029 this for scalar and packed array types. */
8037 && TYPE_PACKED_ARRAY_TYPE_P
8040 {
8042 post_error_ne_tree
8046 }
8048 /* Otherwise, set the RM size proper for integral types... */
8055 /* ...or the Ada size for record and union types. */
8059 }
8060 \f
8061 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
8062 a type or object whose present alignment is ALIGN. If this alignment is
8063 valid, return it. Otherwise, give an error and return ALIGN. */
8065 static unsigned int
8067 {
8070 Node_Id gnat_error_node;
8072 /* Don't worry about checking alignment if alignment was not specified
8073 by the source program and we already posted an error for this entity. */
8077 /* Post the error on the alignment clause if any. Note, for the implicit
8078 base type of an array type, the alignment clause is on the first
8079 subtype. */
8087 gnat_error_node =
8090 else
8093 /* Within GCC, an alignment is an integer, so we must make sure a value is
8094 specified that fits in that range. Also, there is an upper bound to
8095 alignments we can support/allow. */
8103 {
8107 /* If the default alignment of "double" or larger scalar types is
8108 specifically capped and the new alignment is above the cap, do
8109 not post an error and change the alignment only if there is an
8110 alignment clause; this makes it possible to have the associated
8111 GCC type overaligned by default for performance reasons. */
8113 {
8114 Entity_Id gnat_type
8116 is_capped_double
8118 }
8120 {
8121 Entity_Id gnat_type
8123 is_capped_double
8125 }
8126 else
8130 {
8133 }
8134 else
8135 {
8142 }
8143 }
8144 else
8145 {
8149 }
8152 }
8153 \f
8154 /* Verify that TYPE is something we can implement atomically. If not, issue
8155 an error for GNAT_ENTITY. COMPONENT_P is true if we are being called to
8156 process a component type. */
8158 static void
8160 {
8162 Node_Id gnat_node;
8163 machine_mode mode;
8166 tree size;
8168 /* If this is an anonymous base type, nothing to check, the error will be
8169 reported on the source type if need be. */
8178 /* Consider all aligned floating-point types atomic and any aligned types
8179 that are represented by integers no wider than a machine word. */
8186 /* For the moment, also allow anything that has an alignment equal to its
8187 size and which is smaller than a word. */
8198 {
8199 unsigned char pragma_id
8204 {
8207 }
8208 }
8213 else
8216 }
8217 \f
8219 /* Helper for the intrin compatibility checks family. Evaluate whether
8220 two types are definitely incompatible. */
8222 static bool
8224 {
8239 {
8246 /* Assume designated types are ok. We'd need to account for char * and
8247 void * variants to do better, which could rapidly get messy and isn't
8248 clearly worth the effort. */
8253 }
8256 }
8258 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8259 on the Ada/builtin argument lists for the INB binding. */
8261 static bool
8263 {
8269 /* Sequence position of the last argument we checked. */
8273 {
8277 /* If we've exhausted both lists simultaneously, we're done. */
8281 /* If one list is shorter than the other, they fail to match. */
8285 /* If we're done with the Ada args and not with the internal builtin
8286 args, or the other way around, complain. */
8289 {
8292 }
8296 {
8300 }
8302 /* Otherwise, check that types match for the current argument. */
8303 argpos ++;
8305 {
8309 }
8314 }
8317 }
8319 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8320 on the Ada/builtin return values for the INB binding. */
8322 static bool
8324 {
8328 /* Accept function imported as procedure, common and convenient. */
8333 /* If return type is Address (integer type), map it to void *. */
8337 /* Check return types compatibility otherwise. Note that this
8338 handles void/void as well. */
8340 {
8344 }
8347 }
8349 /* Check and return whether the Ada and gcc builtin profiles bound by INB are
8350 compatible. Issue relevant warnings when they are not.
8352 This is intended as a light check to diagnose the most obvious cases, not
8353 as a full fledged type compatibility predicate. It is the programmer's
8354 responsibility to ensure correctness of the Ada declarations in Imports,
8355 especially when binding straight to a compiler internal. */
8357 static bool
8359 {
8360 /* Check compatibility on return values and argument lists, each responsible
8361 for posting warnings as appropriate. Ensure use of the proper sloc for
8362 this purpose. */
8375 }
8376 \f
8377 /* Return a FIELD_DECL node modeled on OLD_FIELD. FIELD_TYPE is its type
8378 and RECORD_TYPE is the type of the parent. If SIZE is nonzero, it is the
8379 specified size for this field. POS_LIST is a position list describing
8380 the layout of OLD_FIELD and SUBST_LIST a substitution list to be applied
8381 to this layout. */
8383 static tree
8387 {
8399 /* If the position is now a constant, we can set it as the position of the
8400 field when we make it. Otherwise, we need to deal with it specially. */
8403 else
8406 new_field
8412 {
8414 /* Finalize the position. */
8423 }
8431 }
8433 /* Create the REP part of RECORD_TYPE with REP_TYPE. If MIN_SIZE is nonzero,
8434 it is the minimal size the REP_PART must have. */
8436 static tree
8438 {
8439 tree field;
8449 }
8451 /* Return the REP part of RECORD_TYPE, if any. Otherwise return NULL. */
8453 static tree
8455 {
8458 /* The REP part is the first field, internal, another record, and its name
8459 starts with an 'R'. */
8467 }
8469 /* Return the variant part of RECORD_TYPE, if any. Otherwise return NULL. */
8471 tree
8473 {
8474 tree field;
8476 /* The variant part is the only internal field that is a qualified union. */
8483 }
8485 /* Return a new variant part modeled on OLD_VARIANT_PART. VARIANT_LIST is
8486 the list of variants to be used and RECORD_TYPE is the type of the parent.
8487 POS_LIST is a position list describing the layout of fields present in
8488 OLD_VARIANT_PART and SUBST_LIST a substitution list to be applied to this
8489 layout. */
8491 static tree
8496 {
8504 /* First create the type of the variant part from that of the old one. */
8510 /* If the position of the variant part is constant, subtract it from the
8511 size of the type of the parent to get the new size. This manual CSE
8512 reduces the code size when not optimizing. */
8514 {
8524 first_bit));
8527 }
8528 else
8531 /* Now finish up the new variants and populate the union type. */
8533 {
8537 /* Skip variants that don't belong to this nesting level. */
8541 /* Retrieve the list of fields already added to the new variant. */
8545 /* If the old variant had a variant subpart, we need to create a new
8546 variant subpart and add it to the field list. */
8550 {
8551 tree new_variant_subpart
8556 }
8558 /* Finish up the new variant and create the field. No need for debug
8559 info thanks to the XVS type. */
8563 Empty);
8565 new_field
8573 }
8575 /* Finish up the union type and create the variant part. No need for debug
8576 info thanks to the XVS type. Note that we don't reverse the field list
8577 because VARIANT_LIST has been traversed in reverse order. */
8581 Empty);
8583 new_variant_part
8589 /* With multiple discriminants it is possible for an inner variant to be
8590 statically selected while outer ones are not; in this case, the list
8591 of fields of the inner variant is not flattened and we end up with a
8592 qualified union with a single member. Drop the useless container. */
8594 {
8603 }
8606 }
8608 /* Copy the size (and alignment and alias set) from OLD_TYPE to NEW_TYPE,
8609 which are both RECORD_TYPE, after applying the substitutions described
8610 in SUBST_LIST. */
8612 static void
8615 {
8639 SET_TYPE_ADA_SIZE
8643 /* Finalize the size. */
8646 }
8648 /* Add a parallel type to GNU_TYPE, the translation of GNAT_ENTITY, which is
8649 the implementation type of a packed array type (Is_Packed_Array_Impl_Type).
8650 The parallel type is the original array type if it has been translated. */
8652 static void
8654 {
8655 Entity_Id gnat_original_array_type
8657 tree gnu_original_array_type;
8668 }
8669 \f
8670 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a
8671 type with all size expressions that contain F in a PLACEHOLDER_EXPR
8672 updated by replacing F with R.
8674 The function doesn't update the layout of the type, i.e. it assumes
8675 that the substitution is purely formal. That's why the replacement
8676 value R must itself contain a PLACEHOLDER_EXPR. */
8678 tree
8680 {
8681 tree nt;
8686 {
8692 /* First the domain types of arrays. */
8695 {
8707 SET_TYPE_INDEX_TYPE
8711 }
8713 /* Then the subtypes. */
8716 {
8728 }
8740 /* These should never show up here. */
8744 {
8761 }
8766 {
8768 tree field;
8770 /* Start out with no fields, make new fields, and chain them
8771 in. If we haven't actually changed the type of any field,
8772 discard everything we've done and return the old type. */
8777 {
8782 {
8785 }
8789 {
8792 }
8794 /* Do the substitution inside the qualifier, if any. */
8796 {
8799 {
8802 }
8803 }
8810 }
8820 }
8824 }
8825 }
8826 \f
8827 /* Return the RM size of GNU_TYPE. This is the actual number of bits
8828 needed to represent the object. */
8830 tree
8832 {
8833 /* For integral types, we store the RM size explicitly. */
8837 /* Return the RM size of the actual data plus the size of the template. */
8840 return
8845 /* For record or union types, we store the size explicitly. */
8851 /* For other types, this is just the size. */
8853 }
8854 \f
8855 /* Return the name to be used for GNAT_ENTITY. If a type, create a
8856 fully-qualified name, possibly with type information encoding.
8857 Otherwise, return the name. */
8859 tree
8861 {
8864 }
8866 /* Return an identifier representing the external name to be used for
8867 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
8868 and the specified suffix. */
8870 tree
8872 {
8880 /* A variable using the Stdcall convention lives in a DLL. We adjust
8881 its name to use the jump table, the _imp__NAME contains the address
8882 for the NAME variable. */
8885 {
8891 }
8894 }
8896 /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
8897 string, return a new IDENTIFIER_NODE that is the concatenation of
8898 the name followed by "___" and the specified suffix. */
8900 tree
8902 {
8909 }
8911 /* Initialize data structures of the decl.c module. */
8913 void
8915 {
8916 /* Initialize the cache of annotated values. */
8918 }
8920 /* Destroy data structures of the decl.c module. */
8922 void
8924 {
8925 /* Destroy the cache of annotated values. */
8928 }