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1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2015, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License along with GCC; see the file COPYING3. If not see *
19 * <http://www.gnu.org/licenses/>. *
20 * *
21 * GNAT was originally developed by the GNAT team at New York University. *
22 * Extensive contributions were provided by Ada Core Technologies Inc. *
23 * *
24 ****************************************************************************/
66 /* "stdcall" and "thiscall" conventions should be processed in a specific way
67 on 32-bit x86/Windows only. The macros below are helpers to avoid having
68 to check for a Windows specific attribute throughout this unit. */
70 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
71 #ifdef TARGET_64BIT
72 #define Has_Stdcall_Convention(E) \
73 (!TARGET_64BIT && Convention (E) == Convention_Stdcall)
74 #define Has_Thiscall_Convention(E) \
75 (!TARGET_64BIT && is_cplusplus_method (E))
76 #else
77 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
78 #define Has_Thiscall_Convention(E) (is_cplusplus_method (E))
79 #endif
80 #else
81 #define Has_Stdcall_Convention(E) 0
82 #define Has_Thiscall_Convention(E) 0
83 #endif
87 /* Stack realignment is necessary for functions with foreign conventions when
88 the ABI doesn't mandate as much as what the compiler assumes - that is, up
89 to PREFERRED_STACK_BOUNDARY.
91 Such realignment can be requested with a dedicated function type attribute
92 on the targets that support it. We define FOREIGN_FORCE_REALIGN_STACK to
93 characterize the situations where the attribute should be set. We rely on
94 compiler configuration settings for 'main' to decide. */
96 #ifdef MAIN_STACK_BOUNDARY
97 #define FOREIGN_FORCE_REALIGN_STACK \
98 (MAIN_STACK_BOUNDARY < PREFERRED_STACK_BOUNDARY)
99 #else
100 #define FOREIGN_FORCE_REALIGN_STACK 0
101 #endif
103 struct incomplete
104 {
106 tree old_type;
107 Entity_Id full_type;
108 };
110 /* These variables are used to defer recursively expanding incomplete types
111 while we are processing an array, a record or a subprogram type. */
115 /* This variable is used to delay expanding From_Limited_With types until the
116 end of the spec. */
120 tree discriminant;
121 tree replacement;
126 /* The type of the variant. */
127 tree type;
129 /* The associated field. */
130 tree field;
132 /* The value of the qualifier. */
133 tree qual;
135 /* The type of the variant after transformation. */
136 tree new_type;
140 /* A hash table used to cache the result of annotate_value. */
143 {
146 {
148 }
152 {
154 }
156 static void
158 {
164 else
166 }
167 };
215 /* The relevant constituents of a subprogram binding to a GCC builtin. Used
216 to pass around calls performing profile compatibility checks. */
225 \f
226 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
227 entity, return the equivalent GCC tree for that entity (a ..._DECL node)
228 and associate the ..._DECL node with the input GNAT defining identifier.
230 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
231 initial value (in GCC tree form). This is optional for a variable. For
232 a renamed entity, GNU_EXPR gives the object being renamed.
234 DEFINITION is nonzero if this call is intended for a definition. This is
235 used for separate compilation where it is necessary to know whether an
236 external declaration or a definition must be created if the GCC equivalent
237 was not created previously. The value of 1 is normally used for a nonzero
238 DEFINITION, but a value of 2 is used in special circumstances, defined in
239 the code. */
241 tree
243 {
244 /* Contains the kind of the input GNAT node. */
246 /* True if this is a type. */
248 /* True if debug info is requested for this entity. */
250 /* True if this entity is to be considered as imported. */
251 const bool imported_p
253 /* For a type, contains the equivalent GNAT node to be used in gigi. */
255 /* Temporary used to walk the GNAT tree. */
256 Entity_Id gnat_temp;
257 /* Contains the GCC DECL node which is equivalent to the input GNAT node.
258 This node will be associated with the GNAT node by calling at the end
259 of the `switch' statement. */
261 /* Contains the GCC type to be used for the GCC node. */
263 /* Contains the GCC size tree to be used for the GCC node. */
265 /* Contains the GCC name to be used for the GCC node. */
266 tree gnu_entity_name;
267 /* True if we have already saved gnu_decl as a GNAT association. */
269 /* True if we incremented defer_incomplete_level. */
271 /* True if we incremented force_global. */
273 /* True if we should check to see if elaborated during processing. */
275 /* True if we made GNU_DECL and its type here. */
277 /* Size and alignment of the GCC node, if meaningful. */
279 /* Contains the list of attributes directly attached to the entity. */
282 /* Since a use of an Itype is a definition, process it as such if it
283 is not in a with'ed unit. */
285 && is_type
289 {
290 /* Ensure that we are in a subprogram mentioned in the Scope chain of
291 this entity, our current scope is global, or we encountered a task
292 or entry (where we can't currently accurately check scoping). */
295 {
298 }
303 {
308 gnat_temp
320 && (current_function_decl
322 {
325 }
326 }
328 /* This abort means the Itype has an incorrect scope, i.e. that its
329 scope does not correspond to the subprogram it is declared in. */
331 }
333 /* If we've already processed this entity, return what we got last time.
334 If we are defining the node, we should not have already processed it.
335 In that case, we will abort below when we try to save a new GCC tree
336 for this object. We also need to handle the case of getting a dummy
337 type when a Full_View exists but be careful so as not to trigger its
338 premature elaboration. */
341 {
350 {
351 gnu_decl
355 }
358 }
360 /* If this is a numeric or enumeral type, or an access type, a nonzero Esize
361 must be specified unless it was specified by the programmer. Exceptions
362 are for access-to-protected-subprogram types and all access subtypes, as
363 another GNAT type is used to lay out the GCC type for them. */
374 /* The RM size must be specified for all discrete and fixed-point types. */
378 /* If we get here, it means we have not yet done anything with this entity.
379 If we are not defining it, it must be a type or an entity that is defined
380 elsewhere or externally, otherwise we should have defined it already. */
382 || type_annotate_only
383 || is_type
390 /* Get the name of the entity and set up the line number and filename of
391 the original definition for use in any decl we make. Make sure we do not
392 inherit another source location. */
398 /* For cases when we are not defining (i.e., we are referencing from
399 another compilation unit) public entities, show we are at global level
400 for the purpose of computing scopes. Don't do this for components or
401 discriminants since the relevant test is whether or not the record is
402 being defined. */
410 /* Handle any attributes directly attached to the entity. */
414 /* Do some common processing for types. */
416 {
417 /* Compute the equivalent type to be used in gigi. */
420 /* Machine_Attributes on types are expected to be propagated to
421 subtypes. The corresponding Gigi_Rep_Items are only attached
422 to the first subtype though, so we handle the propagation here. */
429 /* Compute a default value for the size of an elementary type. */
431 {
441 else
446 }
447 }
450 {
452 /* If this is a use of a deferred constant without address clause,
453 get its full definition. */
457 {
458 gnu_decl
462 }
464 /* If we have an external constant that we are not defining, get the
465 expression that is was defined to represent. We may throw it away
466 later if it is not a constant. But do not retrieve the expression
467 if it is an allocator because the designated type might be dummy
468 at this point. */
474 {
478 /* The expression may contain N_Expression_With_Actions nodes and
479 thus object declarations from other units. In this case, even
480 though the expression will eventually be discarded since not a
481 constant, the declarations would be stuck either in the global
482 varpool or in the current scope. Therefore we force the local
483 context and create a fake scope that we'll zap at the end. */
485 {
488 }
498 }
500 /* Ignore deferred constant definitions without address clause since
501 they are processed fully in the front-end. If No_Initialization
502 is set, this is not a deferred constant but a constant whose value
503 is built manually. And constants that are renamings are handled
504 like variables. */
506 && !gnu_expr
510 {
514 }
516 /* Ignore constant definitions already marked with the error node. See
517 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
519 && gnu_expr
522 {
525 }
534 {
535 /* The GNAT record where the component was defined. */
538 /* If the entity is a discriminant of an extended tagged type used to
539 rename a discriminant of the parent type, return the latter. */
542 {
543 gnu_decl
548 }
550 /* If the entity is an inherited component (in the case of extended
551 tagged record types), just return the original entity, which must
552 be a FIELD_DECL. Likewise for discriminants. If the entity is a
553 non-girder discriminant (in the case of derived untagged record
554 types), return the stored discriminant it renames. */
557 {
558 gnu_decl
563 }
565 /* Otherwise, if we are not defining this and we have no GCC type
566 for the containing record, make one for it. Then we should
567 have made our own equivalent. */
569 {
570 /* ??? If this is in a record whose scope is a protected
571 type and we have an Original_Record_Component, use it.
572 This is a workaround for major problems in protected type
573 handling. */
577 {
578 gnu_decl
584 }
590 }
592 else
593 /* Here we have no GCC type and this is a reference rather than a
594 definition. This should never happen. Most likely the cause is
595 reference before declaration in the GNAT tree for gnat_entity. */
597 }
603 /* Simple variables, loop variables, Out parameters and exceptions. */
604 object:
605 {
606 /* Always create a variable for volatile objects and variables seen
607 constant but with a Linker_Section pragma. */
608 bool const_flag
625 tree gnu_object_size;
628 {
632 else
634 }
636 /* Get the type after elaborating the renamed object. */
639 /* If this is a standard exception definition, then use the standard
640 exception type. This is necessary to make sure that imported and
641 exported views of exceptions are properly merged in LTO mode. */
646 /* For a debug renaming declaration, build a debug-only entity. */
648 {
649 /* Force a non-null value to make sure the symbol is retained. */
653 integer_minus_one_node));
660 }
662 /* If this is a loop variable, its type should be the base type.
663 This is because the code for processing a loop determines whether
664 a normal loop end test can be done by comparing the bounds of the
665 loop against those of the base type, which is presumed to be the
666 size used for computation. But this is not correct when the size
667 of the subtype is smaller than the type. */
671 /* Reject non-renamed objects whose type is an unconstrained array or
672 any object whose type is a dummy type or void. */
677 {
680 force_global--;
682 }
684 /* If an alignment is specified, use it if valid. Note that exceptions
685 are objects but don't have an alignment. We must do this before we
686 validate the size, since the alignment can affect the size. */
688 {
694 /* No point in changing the type if there is an address clause
695 as the final type of the object will be a reference type. */
698 else
699 {
702 gnu_type
706 /* If a padding record was made, declare it now since it will
707 never be declared otherwise. This is necessary to ensure
708 that its subtrees are properly marked. */
712 }
713 }
715 /* If we are defining the object, see if it has a Size and validate it
716 if so. If we are not defining the object and a Size clause applies,
717 simply retrieve the value. We don't want to ignore the clause and
718 it is expected to have been validated already. Then get the new
719 type, if any. */
728 {
729 gnu_type
735 }
737 /* If this object has self-referential size, it must be a record with
738 a default discriminant. We are supposed to allocate an object of
739 the maximum size in this case, unless it is a constant with an
740 initializing expression, in which case we can get the size from
741 that. Note that the resulting size may still be a variable, so
742 this may end up with an indirect allocation. */
745 {
747 {
750 {
751 /* If the initializing expression is itself a constant,
752 despite having a nominal type with self-referential
753 size, we can get the size directly from it. */
755 && TYPE_IS_PADDING_P
759 || DECL_READONLY_ONCE_ELAB
762 else
763 gnu_size
765 }
766 else
768 }
769 /* We may have no GNU_EXPR because No_Initialization is
770 set even though there's an Expression. */
775 gnu_size
777 (Etype
779 else
780 {
783 }
785 /* If we are at global level and the size isn't constant, call
786 elaborate_expression_1 to make a variable for it rather than
787 calculating it each time. */
792 }
794 /* If the size is zero byte, make it one byte since some linkers have
795 troubles with zero-sized objects. If the object will have a
796 template, that will make it nonzero so don't bother. Also avoid
797 doing that for an object renaming or an object with an address
798 clause, as we would lose useful information on the view size
799 (e.g. for null array slices) and we are not allocating the object
800 here anyway. */
812 /* If this is an object with no specified size and alignment, and
813 if either it is atomic or we are not optimizing alignment for
814 space and it is composite and not an exception, an Out parameter
815 or a reference to another object, and the size of its type is a
816 constant, set the alignment to the smallest one which is not
817 smaller than the size, with an appropriate cap. */
826 && !imported_p
830 {
833 /* No point in promoting the alignment if this doesn't prevent
834 BLKmode access to the object, in particular block copy, as
835 this will for example disable the NRV optimization for it.
836 No point in jumping through all the hoops needed in order
837 to support BIGGEST_ALIGNMENT if we don't really have to.
838 So we cap to the smallest alignment that corresponds to
839 a known efficient memory access pattern of the target. */
841 {
844 }
845 else
846 {
849 }
856 else
859 /* But make sure not to under-align the object. */
863 /* And honor the minimum valid atomic alignment, if any. */
864 #ifdef MINIMUM_ATOMIC_ALIGNMENT
867 #endif
868 }
870 /* If the object is set to have atomic components, find the component
871 type and validate it.
873 ??? Note that we ignore Has_Volatile_Components on objects; it's
874 not at all clear what to do in that case. */
876 {
885 }
887 /* Now check if the type of the object allows atomic access. Note
888 that we must test the type, even if this object has size and
889 alignment to allow such access, because we will be going inside
890 the padded record to assign to the object. We could fix this by
891 always copying via an intermediate value, but it's not clear it's
892 worth the effort. */
896 /* If this is an aliased object with an unconstrained nominal subtype,
897 make a type that includes the template. */
901 {
902 tree gnu_array
904 gnu_type
906 gnu_type,
909 debug_info_p);
910 }
912 /* ??? If this is an object of CW type initialized to a value, try to
913 ensure that the object is sufficient aligned for this value, but
914 without pessimizing the allocation. This is a kludge necessary
915 because we don't support dynamic alignment. */
922 #ifdef MINIMUM_ATOMIC_ALIGNMENT
923 /* If the size is a constant and no alignment is specified, force
924 the alignment to be the minimum valid atomic alignment. The
925 restriction on constant size avoids problems with variable-size
926 temporaries; if the size is variable, there's no issue with
927 atomic access. Also don't do this for a constant, since it isn't
928 necessary and can interfere with constant replacement. Finally,
929 do not do it for Out parameters since that creates an
930 size inconsistency with In parameters. */
940 #endif
942 /* Make a new type with the desired size and alignment, if needed.
943 But do not take into account alignment promotions to compute the
944 size of the object. */
947 {
953 /* If a padding record was made, declare it now since it will
954 never be declared otherwise. This is necessary to ensure
955 that its subtrees are properly marked. */
959 }
961 /* If this is a renaming, avoid as much as possible to create a new
962 object. However, in several cases, creating it is required.
963 This processing needs to be applied to the raw expression so
964 as to make it more likely to rename the underlying object. */
966 {
969 /* If the renamed object had padding, strip off the reference
970 to the inner object and reset our type. */
973 /* Strip useless conversions around the object. */
975 {
978 }
980 /* Or else, if the renamed object has an unconstrained type with
981 default discriminant, use the padded type. */
984 == gnu_type
988 /* Case 1: If this is a constant renaming stemming from a function
989 call, treat it as a normal object whose initial value is what is
990 being renamed. RM 3.3 says that the result of evaluating a
991 function call is a constant object. Treat constant literals
992 the same way. As a consequence, it can be the inner object of
993 a constant renaming. In this case, the renaming must be fully
994 instantiated, i.e. it cannot be a mere reference to (part of) an
995 existing object. */
997 {
1004 }
1006 /* Otherwise, see if we can proceed with a stabilized version of
1007 the renamed entity or if we need to make a new object. */
1009 {
1013 /* Case 2: If the renaming entity need not be materialized and
1014 the renamed expression is something we can stabilize, use
1015 that for the renaming. At the global level, we can only do
1016 this if we know no SAVE_EXPRs need be made, because the
1017 expression we return might be used in arbitrary conditional
1018 branches so we must force the evaluation of the SAVE_EXPRs
1019 immediately and this requires a proper function context.
1020 Note that an external constant is at the global level. */
1026 {
1027 maybe_stable_expr
1031 {
1032 /* ??? No DECL_EXPR is created so we need to mark
1033 the expression manually lest it is shared. */
1042 /* This assertion will fail if the renamed object
1043 isn't aligned enough as to make it possible to
1044 honor the alignment set on the renaming. */
1046 {
1047 unsigned int renamed_align
1052 }
1054 }
1056 /* The stabilization failed. Keep maybe_stable_expr
1057 untouched here to let the pointer case below know
1058 about that failure. */
1059 }
1061 /* Case 3: Make this into a constant pointer to the object we
1062 are to rename and attach the object to the pointer if it is
1063 something we can stabilize.
1065 From the proper scope, attached objects will be referenced
1066 directly instead of indirectly via the pointer to avoid
1067 subtle aliasing problems with non-addressable entities.
1068 They have to be stable because we must not evaluate the
1069 variables in the expression every time the renaming is used.
1070 The pointer is called a "renaming" pointer in this case.
1072 In the rare cases where we cannot stabilize the renamed
1073 object, we just make a "bare" pointer and the renamed
1074 object will always be accessed indirectly through it.
1076 Note that we need to preserve the volatility of the renamed
1077 object through the indirection. */
1079 gnu_type
1085 /* If the previous attempt at stabilizing failed, there is
1086 no point in trying again and we reuse the result without
1087 attaching it to the pointer. In this case it will only
1088 be used as the initializing expression of the pointer and
1089 thus needs no special treatment with regard to multiple
1090 evaluations.
1092 Otherwise, try to stabilize and attach the expression to
1093 the pointer if the stabilization succeeds.
1095 Note that this might introduce SAVE_EXPRs and we don't
1096 check whether we are at the global level or not. This
1097 is fine since we are building a pointer initializer and
1098 neither the pointer nor the initializing expression can
1099 be accessed before the pointer elaboration has taken
1100 place in a correct program.
1102 These SAVE_EXPRs will be evaluated at the right place
1103 by either the evaluation of the initializer for the
1104 non-global case or the elaboration code for the global
1105 case, and will be attached to the elaboration procedure
1106 in the latter case. */
1108 {
1109 maybe_stable_expr
1114 }
1119 else
1120 gnu_expr
1125 }
1126 }
1128 /* Make a volatile version of this object's type if we are to make
1129 the object volatile. We also interpret 13.3(19) conservatively
1130 and disallow any optimizations for such a non-constant object. */
1132 || (!const_flag
1135 || imported_p
1140 /* If we are defining an aliased object whose nominal subtype is
1141 unconstrained, the object is a record that contains both the
1142 template and the object. If there is an initializer, it will
1143 have already been converted to the right type, but we need to
1144 create the template if there is no initializer. */
1146 && !gnu_expr
1149 /* Beware that padding might have been introduced above. */
1152 == RECORD_TYPE
1153 && TYPE_CONTAINS_TEMPLATE_P
1155 {
1156 tree template_field
1164 NULL_TREE);
1167 }
1169 /* Convert the expression to the type of the object except in the
1170 case where the object's type is unconstrained or the object's type
1171 is a padded record whose field is of self-referential size. In
1172 the former case, converting will generate unnecessary evaluations
1173 of the CONSTRUCTOR to compute the size and in the latter case, we
1174 want to only copy the actual data. Also don't convert to a record
1175 type with a variant part from a record type without one, to keep
1176 the object simpler. */
1181 && CONTAINS_PLACEHOLDER_P
1189 /* If this is a pointer that doesn't have an initializing expression,
1190 initialize it to NULL, unless the object is imported. */
1193 && !gnu_expr
1197 /* If we are defining the object and it has an Address clause, we must
1198 either get the address expression from the saved GCC tree for the
1199 object if it has a Freeze node, or elaborate the address expression
1200 here since the front-end has guaranteed that the elaboration has no
1201 effects in this case. */
1203 {
1205 tree gnu_address
1211 /* Ignore the size. It's either meaningless or was handled
1212 above. */
1214 /* Convert the type of the object to a reference type that can
1215 alias everything as per 13.3(19). */
1216 gnu_type
1220 const_flag
1224 /* If this is a deferred constant, the initializer is attached to
1225 the full view. */
1227 gnu_expr
1228 = gnat_to_gnu
1231 /* If we don't have an initializing expression for the underlying
1232 variable, the initializing expression for the pointer is the
1233 specified address. Otherwise, we have to make a COMPOUND_EXPR
1234 to assign both the address and the initial value. */
1237 else
1238 gnu_expr
1240 build_binary_op
1243 gnu_address),
1244 gnu_expr),
1245 gnu_address);
1246 }
1248 /* If it has an address clause and we are not defining it, mark it
1249 as an indirect object. Likewise for Stdcall objects that are
1250 imported. */
1254 {
1255 /* Convert the type of the object to a reference type that can
1256 alias everything as per 13.3(19). */
1257 gnu_type
1261 /* No point in taking the address of an initializing expression
1262 that isn't going to be used. */
1265 /* If it has an address clause whose value is known at compile
1266 time, make the object a CONST_DECL. This will avoid a
1267 useless dereference. */
1269 {
1270 Node_Id gnat_address
1274 {
1277 }
1278 }
1281 }
1283 /* If we are at top level and this object is of variable size,
1284 make the actual type a hidden pointer to the real type and
1285 make the initializer be a memory allocation and initialization.
1286 Likewise for objects we aren't defining (presumed to be
1287 external references from other packages), but there we do
1288 not set up an initialization.
1290 If the object's size overflows, make an allocator too, so that
1291 Storage_Error gets raised. Note that we will never free
1292 such memory, so we presume it never will get allocated. */
1295 || !definition
1297 || (gnu_size
1299 size_binop
1301 bitsize_unit_node)),
1303 || !definition
1305 {
1310 /* In case this was a aliased object whose nominal subtype is
1311 unconstrained, the pointer above will be a thin pointer and
1312 build_allocator will automatically make the template.
1314 If we have a template initializer only (that we made above),
1315 pretend there is none and rely on what build_allocator creates
1316 again anyway. Otherwise (if we have a full initializer), get
1317 the data part and feed that to build_allocator.
1319 If we are elaborating a mutable object, tell build_allocator to
1320 ignore a possibly simpler size from the initializer, if any, as
1321 we must allocate the maximum possible size in this case. */
1323 {
1328 {
1329 gnu_alloc_type
1335 else
1336 gnu_expr
1337 = build_component_ref
1341 }
1346 gnat_entity);
1348 gnu_expr
1352 }
1353 else
1354 {
1357 }
1358 }
1360 /* If this object would go into the stack and has an alignment larger
1361 than the largest stack alignment the back-end can honor, resort to
1362 a variable of "aligning type". */
1365 {
1366 /* Create the new variable. No need for extra room before the
1367 aligned field as this is in automatic storage. */
1368 tree gnu_new_type
1372 tree gnu_new_var
1377 /* Initialize the aligned field if we have an initializer. */
1379 add_stmt_with_node
1381 build_component_ref
1384 gnu_expr),
1385 gnat_entity);
1387 /* And setup this entity as a reference to the aligned field. */
1389 gnu_expr
1390 = build_unary_op
1398 }
1400 /* If this is an aliased object with an unconstrained nominal subtype,
1401 we make its type a thin reference, i.e. the reference counterpart
1402 of a thin pointer, so that it points to the array part. This is
1403 aimed at making it easier for the debugger to decode the object.
1404 Note that we have to do that this late because of the couple of
1405 allocation adjustments that might be made just above. */
1409 {
1410 tree gnu_array
1413 /* In case the object with the template has already been allocated
1414 just above, we have nothing to do here. */
1416 {
1417 tree gnu_unc_var
1423 gnu_expr
1431 }
1433 gnu_type
1435 }
1440 /* Convert the expression to the type of the object except in the
1441 case where the object's type is unconstrained or the object's type
1442 is a padded record whose field is of self-referential size. In
1443 the former case, converting will generate unnecessary evaluations
1444 of the CONSTRUCTOR to compute the size and in the latter case, we
1445 want to only copy the actual data. Also don't convert to a record
1446 type with a variant part from a record type without one, to keep
1447 the object simpler. */
1452 && CONTAINS_PLACEHOLDER_P
1460 /* If this name is external or a name was specified, use it, but don't
1461 use the Interface_Name with an address clause (see cd30005). */
1468 /* If this is an aggregate constant initialized to a constant, force it
1469 to be statically allocated. This saves an initialization copy. */
1471 && const_flag
1480 /* Deal with a pragma Linker_Section on a constant or variable. */
1486 /* Now create the variable or the constant and set various flags. */
1487 gnu_decl
1496 /* If we are defining an Out parameter and optimization isn't enabled,
1497 create a fake PARM_DECL for debugging purposes and make it point to
1498 the VAR_DECL. Suppress debug info for the latter but make sure it
1499 will live in memory so that it can be accessed from within the
1500 debugger through the PARM_DECL. */
1502 && definition
1503 && debug_info_p
1504 && !optimize
1506 {
1513 }
1515 /* If this is a loop parameter, set the corresponding flag. */
1519 /* If this is a renaming pointer, attach the renamed object to it and
1520 register it if we are at the global level. Note that an external
1521 constant is at the global level. */
1523 {
1526 {
1529 }
1530 }
1532 /* If this is a constant and we are defining it or it generates a real
1533 symbol at the object level and we are referencing it, we may want
1534 or need to have a true variable to represent it:
1535 - if optimization isn't enabled, for debugging purposes,
1536 - if the constant is public and not overlaid on something else,
1537 - if its address is taken,
1538 - if either itself or its type is aliased. */
1547 {
1548 tree gnu_corr_var
1552 gnat_entity);
1556 /* As debugging information will be generated for the variable,
1557 do not generate debugging information for the constant. */
1560 else
1562 }
1564 /* If this is a constant, even if we don't need a true variable, we
1565 may need to avoid returning the initializer in every case. That
1566 can happen for the address of a (constant) constructor because,
1567 upon dereferencing it, the constructor will be reinjected in the
1568 tree, which may not be valid in every case; see lvalue_required_p
1569 for more details. */
1573 /* If this object is declared in a block that contains a block with an
1574 exception handler, and we aren't using the GCC exception mechanism,
1575 we must force this variable in memory in order to avoid an invalid
1576 optimization. */
1581 /* If this is a local variable with non-BLKmode and aggregate type,
1582 and optimization isn't enabled, then force it in memory so that
1583 a register won't be allocated to it with possible subparts left
1584 uninitialized and reaching the register allocator. */
1594 /* If we are defining an object with variable size or an object with
1595 fixed size that will be dynamically allocated, and we are using the
1596 setjmp/longjmp exception mechanism, update the setjmp buffer. */
1609 gnat_entity);
1611 /* Back-annotate Esize and Alignment of the object if not already
1612 known. Note that we pick the values of the type, not those of
1613 the object, to shield ourselves from low-level platform-dependent
1614 adjustments like alignment promotion. This is both consistent with
1615 all the treatment above, where alignment and size are set on the
1616 type of the object and not on the object directly, and makes it
1617 possible to support all confirming representation clauses. */
1619 used_by_ref);
1620 }
1624 /* Return a TYPE_DECL for "void" that we previously made. */
1629 /* A special case: for the types Character and Wide_Character in
1630 Standard, we do not list all the literals. So if the literals
1631 are not specified, make this an unsigned integer type. */
1633 {
1637 /* Set TYPE_STRING_FLAG for Character and Wide_Character types.
1638 This is needed by the DWARF-2 back-end to distinguish between
1639 unsigned integer types and character types. */
1641 }
1642 else
1643 {
1644 /* We have a list of enumeral constants in First_Literal. We make a
1645 CONST_DECL for each one and build into GNU_LITERAL_LIST the list
1646 to be placed into TYPE_FIELDS. Each node is itself a TREE_LIST
1647 whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
1648 value of the literal. But when we have a regular boolean type, we
1649 simplify this a little by using a BOOLEAN_TYPE. */
1654 Entity_Id gnat_literal;
1667 {
1668 tree gnu_value
1670 tree gnu_literal
1674 /* Do not generate debug info for individual enumerators. */
1677 gnu_list
1679 }
1684 /* Note that the bounds are updated at the end of this function
1685 to avoid an infinite recursion since they refer to the type. */
1687 }
1693 /* For integer types, just make a signed type the appropriate number
1694 of bits. */
1699 {
1700 /* For modular types, make the unsigned type of the proper number
1701 of bits and then set up the modulus, if required. */
1704 /* Packed Array Impl. Types are supposed to be subtypes only. */
1709 /* Get the modulus in this type. If it overflows, assume it is because
1710 it is equal to 2**Esize. Note that there is no overflow checking
1711 done on unsigned type, so we detect the overflow by looking for
1712 a modulus of zero, which is otherwise invalid. */
1716 {
1721 }
1723 /* If the upper bound is not maximal, make an extra subtype. */
1726 {
1733 }
1734 }
1743 /* For integral subtypes, we make a new INTEGER_TYPE. Note that we do
1744 not want to call create_range_type since we would like each subtype
1745 node to be distinct. ??? Historically this was in preparation for
1746 when memory aliasing is implemented, but that's obsolete now given
1747 the call to relate_alias_sets below.
1749 The TREE_TYPE field of the INTEGER_TYPE points to the base type;
1750 this fact is used by the arithmetic conversion functions.
1752 We elaborate the Ancestor_Subtype if it is not in the current unit
1753 and one of our bounds is non-static. We do this to ensure consistent
1754 naming in the case where several subtypes share the same bounds, by
1755 elaborating the first such subtype first, thus using its name. */
1764 /* Set the precision to the Esize except for bit-packed arrays. */
1769 /* This should be an unsigned type if the base type is unsigned or
1770 if the lower bound is constant and non-negative or if the type
1771 is biased. */
1776 else
1780 SET_TYPE_RM_MIN_VALUE
1786 SET_TYPE_RM_MAX_VALUE
1795 /* Inherit our alias set from what we're a subtype of. Subtypes
1796 are not different types and a pointer can designate any instance
1797 within a subtype hierarchy. */
1800 /* One of the above calls might have caused us to be elaborated,
1801 so don't blow up if so. */
1803 {
1806 }
1808 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
1812 /* For a packed array, make the original array type a parallel type. */
1816 discrete_type:
1818 /* We have to handle clauses that under-align the type specially. */
1821 && Present
1824 {
1828 }
1830 /* If the type we are dealing with represents a bit-packed array,
1831 we need to have the bits left justified on big-endian targets
1832 and right justified on little-endian targets. We also need to
1833 ensure that when the value is read (e.g. for comparison of two
1834 such values), we only get the good bits, since the unused bits
1835 are uninitialized. Both goals are accomplished by wrapping up
1836 the modular type in an enclosing record type. */
1839 {
1842 /* Set the RM size before wrapping up the original type. */
1847 /* Create a stripped-down declaration, mainly for debugging. */
1849 gnat_entity);
1851 /* Now save it and build the enclosing record type. */
1861 /* Propagate the alignment of the modular type to the record type,
1862 unless there is an alignment clause that under-aligns the type.
1863 This means that bit-packed arrays are given "ceil" alignment for
1864 their size by default, which may seem counter-intuitive but makes
1865 it possible to overlay them on modular types easily. */
1869 /* Propagate the reverse storage order flag to the record type so
1870 that the required byte swapping is performed when retrieving the
1871 enclosed modular value. */
1877 /* Don't declare the field as addressable since we won't be taking
1878 its address and this would prevent create_field_decl from making
1879 a bitfield. */
1880 gnu_field
1884 /* Do not emit debug info until after the parallel type is added. */
1890 {
1891 /* Make the original array type a parallel type. */
1895 }
1896 }
1898 /* If the type we are dealing with has got a smaller alignment than the
1899 natural one, we need to wrap it up in a record type and misalign the
1900 latter; we reuse the padding machinery for this purpose. Note that,
1901 even if the record type is marked as packed because of misalignment,
1902 we don't pack the field so as to give it the size of the type. */
1904 {
1907 /* Set the RM size before wrapping up the type. */
1911 /* Create a stripped-down declaration, mainly for debugging. */
1913 gnat_entity);
1915 /* Now save it and build the enclosing record type. */
1927 /* Don't declare the field as addressable since we won't be taking
1928 its address and this would prevent create_field_decl from making
1929 a bitfield. */
1930 gnu_field
1938 }
1943 /* The type of the Low and High bounds can be our type if this is
1944 a type from Standard, so set them at the end of the function. */
1951 /* See the E_Signed_Integer_Subtype case for the rationale. */
1968 SET_TYPE_RM_MIN_VALUE
1974 SET_TYPE_RM_MAX_VALUE
1980 /* Inherit our alias set from what we're a subtype of, as for
1981 integer subtypes. */
1984 /* One of the above calls might have caused us to be elaborated,
1985 so don't blow up if so. */
1989 /* Array Types and Subtypes
1991 Unconstrained array types are represented by E_Array_Type and
1992 constrained array types are represented by E_Array_Subtype. There
1993 are no actual objects of an unconstrained array type; all we have
1994 are pointers to that type.
1996 The following fields are defined on array types and subtypes:
1998 Component_Type Component type of the array.
1999 Number_Dimensions Number of dimensions (an int).
2000 First_Index Type of first index. */
2003 {
2004 const bool convention_fortran_p
2007 tree gnu_template_type;
2008 tree gnu_ptr_template;
2015 tree comp_type;
2017 /* Create the type for the component now, as it simplifies breaking
2018 type reference loops. */
2019 comp_type
2022 {
2023 /* As a side effect, the type may have been translated. */
2026 }
2028 /* We complete an existing dummy fat pointer type in place. This both
2029 avoids further complex adjustments in update_pointer_to and yields
2030 better debugging information in DWARF by leveraging the support for
2031 incomplete declarations of "tagged" types in the DWARF back-end. */
2034 {
2037 /* Save the contents of the dummy type for update_pointer_to. */
2039 gnu_ptr_template =
2042 }
2043 else
2044 {
2048 }
2050 /* Make a node for the array. If we are not defining the array
2051 suppress expanding incomplete types. */
2055 {
2056 defer_incomplete_level++;
2058 }
2060 /* Build the fat pointer type. Use a "void *" object instead of
2061 a pointer to the array type since we don't have the array type
2062 yet (it will reference the fat pointer via the bounds). */
2063 tem
2071 {
2072 /* We are going to lay it out again so reset the alias set. */
2078 {
2081 }
2082 }
2083 else
2084 {
2087 }
2089 /* Build a reference to the template from a PLACEHOLDER_EXPR that
2090 is the fat pointer. This will be used to access the individual
2091 fields once we build them. */
2095 gnu_template_reference
2100 /* Now create the GCC type for each index and add the fields for that
2101 index to the template. */
2107 {
2109 tree gnu_index_base_type
2114 /* Make the FIELD_DECLs for the low and high bounds of this
2115 type and then make extractions of these fields from the
2116 template. */
2119 gnu_index_base_type,
2127 gnu_index_base_type,
2135 /* We can't use build_component_ref here since the template type
2136 isn't complete yet. */
2139 NULL_TREE);
2142 NULL_TREE);
2148 /* Compute the size of this dimension. See the E_Array_Subtype
2149 case below for the rationale. */
2150 gnu_high
2154 gnu_max,
2157 /* Make a range type with the new range in the Ada base type.
2158 Then make an index type with the size range in sizetype. */
2162 gnu_orig_min,
2163 gnu_orig_max),
2164 gnat_entity);
2166 /* Update the maximum size of the array in elements. */
2168 {
2170 tree gnu_min
2172 tree gnu_max
2174 tree gnu_this_max
2181 else
2182 gnu_max_size
2184 }
2188 }
2190 /* Install all the fields into the template. */
2195 gnu_template_fields
2198 debug_info_p);
2201 /* If Component_Size is not already specified, annotate it with the
2202 size of the component. */
2207 /* Compute the maximum size of the array in units and bits. */
2209 {
2215 }
2216 else
2219 /* Now build the array type. */
2222 {
2231 /* If it is passed by reference, force BLKmode to ensure that
2232 objects of this type will always be put in memory. */
2236 }
2240 /* If an alignment is specified, use it if valid. But ignore it
2241 for the original type of packed array types. If the alignment
2242 was requested with an explicit alignment clause, state so. */
2245 {
2251 }
2255 /* Adjust the type of the pointer-to-array field of the fat pointer
2256 and record the aliasing relationships if necessary. */
2261 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2262 corresponding fat pointer. */
2269 /* If the maximum size doesn't overflow, use it. */
2275 {
2280 }
2284 gnat_entity);
2286 /* Give the fat pointer type a name. If this is a packed array, tell
2287 the debugger how to interpret the underlying bits. */
2290 else
2294 gnat_entity);
2296 /* Create the type to be designated by thin pointers: a record type for
2297 the array and its template. We used to shift the fields to have the
2298 template at a negative offset, but this was somewhat of a kludge; we
2299 now shift thin pointer values explicitly but only those which have a
2300 TYPE_UNCONSTRAINED_ARRAY attached to the designated RECORD_TYPE. */
2303 debug_info_p);
2307 }
2312 /* This is the actual data type for array variables. Multidimensional
2313 arrays are implemented as arrays of arrays. Note that arrays which
2314 have sparse enumeration subtypes as index components create sparse
2315 arrays, which is obviously space inefficient but so much easier to
2316 code for now.
2318 Also note that the subtype never refers to the unconstrained array
2319 type, which is somewhat at variance with Ada semantics.
2321 First check to see if this is simply a renaming of the array type.
2322 If so, the result is the array type. */
2326 ;
2327 else
2328 {
2330 const bool convention_fortran_p
2339 /* First create the GCC type for each index and find out whether
2340 special types are needed for debugging information. */
2343 gnat_base_index
2349 {
2352 tree gnu_orig_min
2355 tree gnu_orig_max
2360 tree gnu_base_index_type
2362 tree gnu_base_index_base_type
2364 tree gnu_base_orig_min
2367 tree gnu_base_orig_max
2370 tree gnu_high;
2372 /* See if the base array type is already flat. If it is, we
2373 are probably compiling an ACATS test but it will cause the
2374 code below to malfunction if we don't handle it specially. */
2378 {
2382 }
2384 /* Similarly, if one of the values overflows in sizetype and the
2385 range is null, use 1..0 for the sizetype bounds. */
2390 {
2394 }
2396 /* If the minimum and maximum values both overflow in sizetype,
2397 but the difference in the original type does not overflow in
2398 sizetype, ignore the overflow indication. */
2402 && !TREE_OVERFLOW
2405 gnu_orig_max,
2406 gnu_orig_min))))
2407 {
2411 }
2413 /* Compute the size of this dimension in the general case. We
2414 need to provide GCC with an upper bound to use but have to
2415 deal with the "superflat" case. There are three ways to do
2416 this. If we can prove that the array can never be superflat,
2417 we can just use the high bound of the index type. */
2420 /* Bit-Packed Array Impl. Types are never superflat. */
2422 && Is_Bit_Packed_Array
2426 /* Otherwise, if the high bound is constant but the low bound is
2427 not, we use the expression (hb >= lb) ? lb : hb + 1 for the
2428 lower bound. Note that the comparison must be done in the
2429 original type to avoid any overflow during the conversion. */
2432 {
2434 gnu_min
2437 boolean_type_node,
2438 gnu_orig_max,
2439 gnu_orig_min),
2440 gnu_min,
2442 size_one_node));
2443 }
2445 /* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
2446 in all the other cases. Note that, here as well as above,
2447 the condition used in the comparison must be equivalent to
2448 the condition (length != 0). This is relied upon in order
2449 to optimize array comparisons in compare_arrays. Moreover
2450 we use int_const_binop for the shift by 1 if the bound is
2451 constant to avoid any unwanted overflow. */
2452 else
2453 gnu_high
2456 boolean_type_node,
2457 gnu_orig_max,
2458 gnu_orig_min),
2459 gnu_max,
2462 size_one_node)
2464 size_one_node));
2466 /* Reuse the index type for the range type. Then make an index
2467 type with the size range in sizetype. */
2470 gnat_entity);
2472 /* Update the maximum size of the array in elements. Here we
2473 see if any constraint on the index type of the base type
2474 can be used in the case of self-referential bound on the
2475 index type of the subtype. We look for a non-"infinite"
2476 and non-self-referential bound from any type involved and
2477 handle each bound separately. */
2479 {
2482 tree gnu_base_index_base_type
2484 tree gnu_base_base_min
2487 tree gnu_base_base_max
2508 else
2509 {
2510 tree gnu_this_max;
2512 /* Use int_const_binop if the bounds are constant to
2513 avoid any unwanted overflow. */
2516 gnu_this_max
2519 gnu_base_max,
2520 gnu_base_min));
2521 else
2522 gnu_this_max
2525 gnu_base_max,
2526 gnu_base_min));
2528 gnu_max_size
2530 }
2531 }
2533 /* We need special types for debugging information to point to
2534 the index types if they have variable bounds, are not integer
2535 types or are biased. */
2544 }
2546 /* Then flatten: create the array of arrays. For an array type
2547 used to implement a packed array, get the component type from
2548 the original array type since the representation clauses that
2549 can affect it are on the latter. */
2552 {
2557 /* One of the above calls might have caused us to be elaborated,
2558 so don't blow up if so. */
2560 {
2563 }
2564 }
2565 else
2566 {
2568 debug_info_p);
2570 /* One of the above calls might have caused us to be elaborated,
2571 so don't blow up if so. */
2573 {
2576 }
2577 }
2579 /* Compute the maximum size of the array in units and bits. */
2581 {
2587 }
2588 else
2591 /* Now build the array type. */
2593 {
2603 /* See the E_Array_Type case for the rationale. */
2607 }
2611 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
2615 /* If we are at file level and this is a multi-dimensional array,
2616 we need to make a variable corresponding to the stride of the
2617 inner dimensions. */
2619 {
2621 tree gnu_arr_type;
2627 {
2635 /* ??? For now, store the size as a multiple of the
2636 alignment of the element type in bytes so that we
2637 can see the alignment from the tree. */
2640 gnat_entity,
2645 /* ??? create_type_decl is not invoked on the inner types so
2646 the MULT_EXPR node built above will never be marked. */
2648 }
2649 }
2651 /* If we need to write out a record type giving the names of the
2652 bounds for debugging purposes, do it now and make the record
2653 type a parallel type. This is not needed for a packed array
2654 since the bounds are conveyed by the original array type. */
2656 && debug_info_p
2658 {
2661 tree gnu_field;
2667 {
2671 /* Make sure to reference the types themselves, and not just
2672 their names, as the debugger may fall back on them. */
2678 }
2682 }
2684 /* If this is a packed array type, make the original array type a
2685 parallel type. Otherwise, do it for the base array type if it
2686 isn't artificial to make sure it is kept in the debug info. */
2688 {
2691 else
2692 {
2693 tree gnu_base_decl
2698 }
2699 }
2706 /* If the size is self-referential and the maximum size doesn't
2707 overflow, use it. */
2709 && gnu_max_size
2714 {
2720 }
2722 /* Set our alias set to that of our base type. This gives all
2723 array subtypes the same alias set. */
2726 /* If this is a packed type, make this type the same as the packed
2727 array type, but do some adjusting in the type first. */
2729 {
2730 Entity_Id gnat_index;
2731 tree gnu_inner;
2733 /* First finish the type we had been making so that we output
2734 debugging information for it. */
2737 gnu_type
2739 /* Make it artificial only if the base type was artificial too.
2740 That's sort of "morally" true and will make it possible for
2741 the debugger to look it up by name in DWARF, which is needed
2742 in order to decode the packed array type. */
2743 gnu_decl
2749 /* Save it as our equivalent in case the call below elaborates
2750 this type again. */
2753 gnu_decl
2766 /* We need to attach the index type to the type we just made so
2767 that the actual bounds can later be put into a template. */
2772 {
2774 {
2775 /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
2776 TYPE_MODULUS for modular types so we make an extra
2777 subtype if necessary. */
2779 {
2780 tree gnu_subtype
2789 }
2793 #ifdef ENABLE_CHECKING
2794 /* Check for other cases of overloading. */
2796 #endif
2797 }
2802 SET_TYPE_ACTUAL_BOUNDS
2809 SET_TYPE_ACTUAL_BOUNDS
2815 }
2816 }
2818 else
2819 /* Abort if packed array with no Packed_Array_Impl_Type. */
2821 }
2825 /* Create the type for a string literal. */
2826 {
2827 Entity_Id gnat_full_type
2832 tree gnu_string_array_type
2834 tree gnu_string_index_type
2837 tree gnu_lower_bound
2840 tree gnu_length
2842 gnu_string_index_type);
2843 tree gnu_upper_bound
2845 gnu_lower_bound,
2848 integer_one_node)));
2849 tree gnu_index_type
2853 gnu_lower_bound,
2854 gnu_upper_bound),
2855 gnat_entity);
2857 gnu_type
2860 gnu_index_type);
2864 }
2867 /* Record Types and Subtypes
2869 The following fields are defined on record types:
2871 Has_Discriminants True if the record has discriminants
2872 First_Discriminant Points to head of list of discriminants
2873 First_Entity Points to head of list of fields
2874 Is_Tagged_Type True if the record is tagged
2876 Implementation of Ada records and discriminated records:
2878 A record type definition is transformed into the equivalent of a C
2879 struct definition. The fields that are the discriminants which are
2880 found in the Full_Type_Declaration node and the elements of the
2881 Component_List found in the Record_Type_Definition node. The
2882 Component_List can be a recursive structure since each Variant of
2883 the Variant_Part of the Component_List has a Component_List.
2885 Processing of a record type definition comprises starting the list of
2886 field declarations here from the discriminants and the calling the
2887 function components_to_record to add the rest of the fields from the
2888 component list and return the gnu type node. The function
2889 components_to_record will call itself recursively as it traverses
2890 the tree. */
2894 {
2895 gnu_type
2896 = build_complex_type
2897 (get_unpadded_type
2900 (Component_List
2901 (Type_Definition
2905 }
2907 {
2910 Node_Id gnat_constr;
2911 Entity_Id gnat_field;
2913 tree gnu_get_parent;
2914 /* Set PACKED in keeping with gnat_to_gnu_field. */
2915 const int packed
2927 const bool is_extension
2933 /* See if all fields have a rep clause. Stop when we find one
2934 that doesn't. */
2942 {
2945 }
2947 /* If this is a record extension, go a level further to find the
2948 record definition. Also, verify we have a Parent_Subtype. */
2950 {
2957 }
2959 /* Make a node for the record. If we are not defining the record,
2960 suppress expanding incomplete types. */
2969 {
2970 defer_incomplete_level++;
2972 }
2974 /* If both a size and rep clause was specified, put the size in
2975 the record type now so that it can get the proper mode. */
2980 /* Always set the alignment here so that it can be used to
2981 set the mode, if it is making the alignment stricter. If
2982 it is invalid, it will be checked again below. If this is to
2983 be Atomic, choose a default alignment of a word unless we know
2984 the size and it's smaller. */
2989 {
2993 }
2994 /* If a type needs strict alignment, the minimum size will be the
2995 type size instead of the RM size (see validate_size). Cap the
2996 alignment, lest it causes this type size to become too large. */
2998 {
3003 }
3004 else
3007 /* If we have a Parent_Subtype, make a field for the parent. If
3008 this record has rep clauses, force the position to zero. */
3010 {
3013 tree gnu_parent;
3015 /* A major complexity here is that the parent subtype will
3016 reference our discriminants in its Stored_Constraint list.
3017 But those must reference the parent component of this record
3018 which is precisely of the parent subtype we have not built yet!
3019 To break the circle we first build a dummy COMPONENT_REF which
3020 represents the "get to the parent" operation and initialize
3021 each of those discriminants to a COMPONENT_REF of the above
3022 dummy parent referencing the corresponding discriminant of the
3023 base type of the parent subtype. */
3028 gnu_dummy_parent_type),
3029 NULL_TREE);
3036 {
3037 tree gnu_field
3040 save_gnu_tree
3045 }
3047 /* Then we build the parent subtype. If it has discriminants but
3048 the type itself has unknown discriminants, this means that it
3049 doesn't contain information about how the discriminants are
3050 derived from those of the ancestor type, so it cannot be used
3051 directly. Instead it is built by cloning the parent subtype
3052 of the underlying record view of the type, for which the above
3053 derivation of discriminants has been made explicit. */
3056 {
3059 /* If we are defining the type, the underlying record
3060 view must already have been elaborated at this point.
3061 Otherwise do it now as its parent subtype cannot be
3062 technically elaborated on its own. */
3065 else
3070 /* Substitute the "get to the parent" of the type for that
3071 of its underlying record view in the cloned type. */
3076 {
3078 tree gnu_ref
3081 gnu_parent
3083 }
3084 }
3085 else
3088 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
3089 initially built. The discriminants must reference the fields
3090 of the parent subtype and not those of its base type for the
3091 placeholder machinery to properly work. */
3093 {
3094 /* The actual parent subtype is the full view. */
3096 {
3099 else
3101 }
3107 {
3108 Entity_Id field;
3117 }
3118 }
3120 /* The "get to the parent" COMPONENT_REF must be given its
3121 proper type... */
3124 /* ...and reference the _Parent field of this record. */
3125 gnu_field
3128 has_rep
3130 has_rep
3136 }
3138 /* Make the fields for the discriminants and put them into the record
3139 unless it's an Unchecked_Union. */
3144 {
3145 /* If this is a record extension and this discriminant is the
3146 renaming of another discriminant, we've handled it above. */
3151 gnu_field
3153 debug_info_p);
3155 /* Make an expression using a PLACEHOLDER_EXPR from the
3156 FIELD_DECL node just created and link that with the
3157 corresponding GNAT defining identifier. */
3165 {
3168 }
3169 }
3171 /* If we have a derived untagged type that renames discriminants in
3172 the root type, the (stored) discriminants are a just copy of the
3173 discriminants of the root type. This means that any constraints
3174 added by the renaming in the derivation are disregarded as far
3175 as the layout of the derived type is concerned. To rescue them,
3176 we change the type of the (stored) discriminants to a subtype
3177 with the bounds of the type of the visible discriminants. */
3179 && !is_extension
3185 /* Ignore access discriminants. */
3188 {
3192 /* If the scope of the discriminant is not the record type,
3193 this means that we're processing the implicit full view
3194 of a type derived from a private discriminated type: in
3195 this case, the Stored_Constraint list is simply copied
3196 from the partial view, see Build_Derived_Private_Type.
3197 So we need to retrieve the corresponding discriminant
3198 of the implicit full view, otherwise we will abort. */
3200 {
3201 Entity_Id field;
3210 }
3213 gnu_ref
3217 /* GNU_REF must be an expression using a PLACEHOLDER_EXPR built
3218 just above for one of the stored discriminants. */
3222 {
3224 tree gnu_subtype
3235 }
3236 }
3238 /* Add the fields into the record type and finish it up. */
3246 /* If it is passed by reference, force BLKmode to ensure that objects
3247 of this type will always be put in memory. */
3254 /* Fill in locations of fields. */
3257 /* If there are any entities in the chain corresponding to components
3258 that we did not elaborate, ensure we elaborate their types if they
3259 are Itypes. */
3269 /* If this is a record type associated with an exception definition,
3270 equate its fields to those of the standard exception type. This
3271 will make it possible to convert between them. */
3273 {
3274 tree gnu_std_field;
3277 gnu_field;
3282 }
3283 }
3287 /* If an equivalent type is present, that is what we should use.
3288 Otherwise, fall through to handle this like a record subtype
3289 since it may have constraints. */
3291 {
3295 }
3297 /* ... fall through ... */
3300 /* If Cloned_Subtype is Present it means this record subtype has
3301 identical layout to that type or subtype and we should use
3302 that GCC type for this one. The front end guarantees that
3303 the component list is shared. */
3305 {
3310 }
3312 /* Otherwise, first ensure the base type is elaborated. Then, if we are
3313 changing the type, make a new type with each field having the type of
3314 the field in the new subtype but the position computed by transforming
3315 every discriminant reference according to the constraints. We don't
3316 see any difference between private and non-private type here since
3317 derivations from types should have been deferred until the completion
3318 of the private type. */
3319 else
3320 {
3322 tree gnu_base_type;
3325 {
3326 defer_incomplete_level++;
3328 }
3333 {
3336 }
3338 /* If this is a record subtype associated with a dispatch table,
3339 strip the suffix. This is necessary to make sure 2 different
3340 subtypes associated with the imported and exported views of a
3341 dispatch table are properly merged in LTO mode. */
3343 {
3350 }
3352 /* When the subtype has discriminants and these discriminants affect
3353 the initial shape it has inherited, factor them in. But for an
3354 Unchecked_Union (it must be an Itype), just return the type.
3355 We can't just test Is_Constrained because private subtypes without
3356 discriminants of types with discriminants with default expressions
3357 are Is_Constrained but aren't constrained! */
3364 {
3370 Entity_Id gnat_field;
3380 /* Set the size, alignment and alias set of the new type to
3381 match that of the old one, doing required substitutions. */
3383 gnu_subst_list);
3387 else
3390 /* Look for REP and variant parts in the base type. */
3394 /* If there is a variant part, we must compute whether the
3395 constraints statically select a particular variant. If
3396 so, we simply drop the qualified union and flatten the
3397 list of fields. Otherwise we'll build a new qualified
3398 union for the variants that are still relevant. */
3400 {
3404 gnu_variant_list
3406 gnu_subst_list,
3407 vNULL);
3409 /* If all the qualifiers are unconditionally true, the
3410 innermost variant is statically selected. */
3414 {
3417 }
3419 /* Otherwise, create the new variants. */
3422 {
3425 tree suffix
3427 IDENTIFIER_POINTER
3435 gnu_subst_list);
3437 }
3438 }
3439 else
3440 {
3443 }
3445 /* Make a list of fields and their position in the base type. */
3446 gnu_pos_list
3453 /* Now go down every component in the subtype and compute its
3454 size and position from those of the component in the base
3455 type and from the constraints of the subtype. */
3463 && Underlying_Type
3466 {
3468 Entity_Id gnat_old_field
3470 tree gnu_old_field
3476 /* If the type is the same, retrieve the GCC type from the
3477 old field to take into account possible adjustments. */
3480 else
3483 /* If there was a component clause, the field types must be
3484 the same for the type and subtype, so copy the data from
3485 the old field to avoid recomputation here. Also if the
3486 field is justified modular and the optimization in
3487 gnat_to_gnu_field was applied. */
3493 {
3496 }
3498 /* If the old field was packed and of constant size, we
3499 have to get the old size here, as it might differ from
3500 what the Etype conveys and the latter might overlap
3501 onto the following field. Try to arrange the type for
3502 possible better packing along the way. */
3506 {
3511 gnu_field_type
3513 }
3515 else
3518 /* If the context of the old field is the base type or its
3519 REP part (if any), put the field directly in the new
3520 type; otherwise look up the context in the variant list
3521 and put the field either in the new type if there is a
3522 selected variant or in one of the new variants. */
3524 || (gnu_rep_part
3527 else
3528 {
3531 tree rep_part;
3539 {
3542 else
3544 }
3545 else
3546 /* The front-end may pass us "ghost" components if
3547 it fails to recognize that a constrained subtype
3548 is statically constrained. Discard them. */
3550 }
3552 /* Now create the new field modeled on the old one. */
3553 gnu_field
3559 /* Put it in one of the new variants directly. */
3561 {
3564 }
3566 /* To match the layout crafted in components_to_record,
3567 if this is the _Tag or _Parent field, put it before
3568 any other fields. */
3573 /* Similarly, if this is the _Controller field, put
3574 it before the other fields except for the _Tag or
3575 _Parent field. */
3577 {
3580 }
3582 /* Otherwise, if this is a regular field, put it after
3583 the other fields. */
3584 else
3585 {
3592 }
3595 }
3597 /* If there is a variant list, a selected variant and the fields
3598 all have a constant position, put them in order of increasing
3599 position to match that of constant CONSTRUCTORs. Likewise if
3600 there is no variant list but a REP part, since the latter has
3601 been flattened in the process. */
3605 {
3617 {
3620 }
3621 }
3623 /* If there is a variant list and no selected variant, we need
3624 to create the nest of variant parts from the old nest. */
3626 {
3627 tree new_variant_part
3633 }
3635 /* Now go through the entities again looking for Itypes that
3636 we have not elaborated but should (e.g., Etypes of fields
3637 that have Original_Components). */
3645 /* Do not emit debug info for the type yet since we're going to
3646 modify it below. */
3651 /* See the E_Record_Type case for the rationale. */
3658 /* Fill in locations of fields. */
3661 /* If debugging information is being written for the type, write
3662 a record that shows what we are a subtype of and also make a
3663 variable that indicates our size, if still variable. */
3665 {
3667 tree gnu_unpad_base_name
3675 build_reference_type
3677 gnu_subtype_marker,
3692 gnat_entity);
3693 }
3698 /* Now we can finalize it. */
3700 }
3702 /* Otherwise, go down all the components in the new type and make
3703 them equivalent to those in the base type. */
3704 else
3705 {
3715 gnat_to_gnu_field_decl
3718 }
3719 }
3723 /* Use the special descriptor type for dispatch tables if needed,
3724 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3725 Note that we are only required to do so for static tables in
3726 order to be compatible with the C++ ABI, but Ada 2005 allows
3727 to extend library level tagged types at the local level so
3728 we do it in the non-static case as well. */
3731 {
3735 }
3737 /* ... fall through ... */
3740 /* If we are not defining this entity, and we have incomplete
3741 entities being processed above us, make a dummy type and
3742 fill it in later. */
3744 {
3747 gnu_type
3748 = build_pointer_type
3763 }
3765 /* ... fall through ... */
3772 {
3773 /* The designated type and its equivalent type for gigi. */
3776 /* Whether it comes from a limited with. */
3777 bool is_from_limited_with
3780 /* The "full view" of the designated type. If this is an incomplete
3781 entity from a limited with, treat its non-limited view as the full
3782 view. Otherwise, if this is an incomplete or private type, use the
3783 full view. In the former case, we might point to a private type,
3784 in which case, we need its full view. Also, we want to look at the
3785 actual type used for the representation, so this takes a total of
3786 three steps. */
3787 Entity_Id gnat_desig_full_direct_first
3788 = (is_from_limited_with
3792 Entity_Id gnat_desig_full_direct
3793 = ((is_from_limited_with
3798 Entity_Id gnat_desig_full
3800 /* The type actually used to represent the designated type, either
3801 gnat_desig_full or gnat_desig_equiv. */
3802 Entity_Id gnat_desig_rep;
3803 /* True if this is a pointer to an unconstrained array. */
3805 /* We want to know if we'll be seeing the freeze node for any
3806 incomplete type we may be pointing to. */
3807 bool in_main_unit
3811 /* True if we make a dummy type here. */
3813 /* The mode to be used for the pointer type. */
3815 /* The GCC type used for the designated type. */
3821 /* If either the designated type or its full view is an unconstrained
3822 array subtype, replace it with the type it's a subtype of. This
3823 avoids problems with multiple copies of unconstrained array types.
3824 Likewise, if the designated type is a subtype of an incomplete
3825 record type, use the parent type to avoid order of elaboration
3826 issues. This can lose some code efficiency, but there is no
3827 alternative. */
3838 /* Set the type that's actually the representation of the designated
3839 type and also flag whether we have a unconstrained array. */
3840 gnat_desig_rep
3842 is_unconstrained_array
3845 /* If we are pointing to an incomplete type whose completion is an
3846 unconstrained array, make dummy fat and thin pointer types to it.
3847 Likewise if the type itself is dummy or an unconstrained array. */
3851 && TYPE_IS_DUMMY_P
3853 || (!in_main_unit
3856 || (in_main_unit
3857 && is_from_limited_with
3859 {
3862 else
3863 {
3866 }
3868 /* If the call above got something that has a pointer, the pointer
3869 is our type. This could have happened either because the type
3870 was elaborated or because somebody else executed the code. */
3874 }
3876 /* If we already know what the full type is, use it. */
3881 /* Get the type of the thing we are to point to and build a pointer to
3882 it. If it is a reference to an incomplete or private type with a
3883 full view that is a record, make a dummy type node and get the
3884 actual type later when we have verified it is safe. */
3890 /* Likewise if we are pointing to a record or array and we are
3891 to defer elaborating incomplete types. We do this as this
3892 access type may be the full view of a private type. Note
3893 that the unconstrained array case is handled above. */
3899 /* If this is a reference from a limited_with type back to our
3900 main unit and there's a freeze node for it, either we have
3901 already processed the declaration and made the dummy type,
3902 in which case we just reuse the latter, or we have not yet,
3903 in which case we make the dummy type and it will be reused
3904 when the declaration is finally processed. In both cases,
3905 the pointer eventually created below will be automatically
3906 adjusted when the freeze node is processed. Note that the
3907 unconstrained array case is handled above. */
3908 || (in_main_unit
3909 && is_from_limited_with
3911 {
3914 }
3916 /* Otherwise handle the case of a pointer to itself. */
3918 {
3919 gnu_type
3923 }
3925 /* If expansion is disabled, the equivalent type of a concurrent type
3926 is absent, so build a dummy pointer type. */
3930 /* Finally, handle the default case where we can just elaborate our
3931 designated type. */
3932 else
3935 /* It is possible that a call to gnat_to_gnu_type above resolved our
3936 type. If so, just return it. */
3938 {
3941 }
3943 /* If we haven't done it yet, build the pointer type the usual way. */
3945 {
3946 /* Modify the designated type if we are pointing only to constant
3947 objects, but don't do it for unconstrained arrays. */
3950 {
3951 gnu_desig_type
3954 /* Some extra processing is required if we are building a
3955 pointer to an incomplete type (in the GCC sense). We might
3956 have such a type if we just made a dummy, or directly out
3957 of the call to gnat_to_gnu_type above if we are processing
3958 an access type for a record component designating the
3959 record type itself. */
3961 {
3962 /* We must ensure that the pointer to variant we make will
3963 be processed by update_pointer_to when the initial type
3964 is completed. Pretend we made a dummy and let further
3965 processing act as usual. */
3968 /* We must ensure that update_pointer_to will not retrieve
3969 the dummy variant when building a properly qualified
3970 version of the complete type. We take advantage of the
3971 fact that get_qualified_type is requiring TYPE_NAMEs to
3972 match to influence build_qualified_type and then also
3973 update_pointer_to here. */
3976 }
3977 }
3979 gnu_type
3982 }
3984 /* If we are not defining this object and we have made a dummy pointer,
3985 save our current definition, evaluate the actual type, and replace
3986 the tentative type we made with the actual one. If we are to defer
3987 actually looking up the actual type, make an entry in the deferred
3988 list. If this is from a limited with, we may have to defer to the
3989 end of the current unit. */
3991 {
3992 tree gnu_old_desig_type;
3995 {
3998 gnu_type = build_pointer_type
4000 }
4001 else
4013 /* Note that the call to gnat_to_gnu_type on gnat_desig_equiv might
4014 update gnu_old_desig_type directly, in which case it will not be
4015 a dummy type any more when we get into update_pointer_to.
4017 This can happen e.g. when the designated type is a record type,
4018 because their elaboration starts with an initial node from
4019 make_dummy_type, which may be the same node as the one we got.
4021 Besides, variants of this non-dummy type might have been created
4022 along the way. update_pointer_to is expected to properly take
4023 care of those situations. */
4025 {
4028 }
4029 else
4030 {
4033 = (is_from_limited_with
4039 }
4040 }
4041 }
4048 else
4049 {
4050 /* The run-time representation is the equivalent type. */
4053 }
4066 /* We treat this as identical to its base type; any constraint is
4067 meaningful only to the front-end.
4069 The designated type must be elaborated as well, if it does
4070 not have its own freeze node. Designated (sub)types created
4071 for constrained components of records with discriminants are
4072 not frozen by the front-end and thus not elaborated by gigi,
4073 because their use may appear before the base type is frozen,
4074 and because it is not clear that they are needed anywhere in
4075 gigi. With the current model, there is no correct place where
4076 they could be elaborated. */
4083 {
4084 /* If we are not defining this entity, and we have incomplete
4085 entities being processed above us, make a dummy type and
4086 elaborate it later. */
4088 {
4091 p->old_type
4096 }
4099 Incomplete_Or_Private_Kind))
4102 }
4107 /* Subprogram Entities
4109 The following access functions are defined for subprograms:
4111 Etype Return type or Standard_Void_Type.
4112 First_Formal The first formal parameter.
4113 Is_Imported Indicates that the subprogram has appeared in
4114 an INTERFACE or IMPORT pragma. For now we
4115 assume that the external language is C.
4116 Is_Exported Likewise but for an EXPORT pragma.
4117 Is_Inlined True if the subprogram is to be inlined.
4119 Each parameter is first checked by calling must_pass_by_ref on its
4120 type to determine if it is passed by reference. For parameters which
4121 are copied in, if they are Ada In Out or Out parameters, their return
4122 value becomes part of a record which becomes the return type of the
4123 function (C function - note that this applies only to Ada procedures
4124 so there is no Ada return type). Additional code to store back the
4125 parameters will be generated on the caller side. This transformation
4126 is done here, not in the front-end.
4128 The intended result of the transformation can be seen from the
4129 equivalent source rewritings that follow:
4131 struct temp {int a,b};
4132 procedure P (A,B: In Out ...) is temp P (int A,B)
4133 begin {
4134 .. ..
4135 end P; return {A,B};
4136 }
4138 temp t;
4139 P(X,Y); t = P(X,Y);
4140 X = t.a , Y = t.b;
4142 For subprogram types we need to perform mainly the same conversions to
4143 GCC form that are needed for procedures and function declarations. The
4144 only difference is that at the end, we make a type declaration instead
4145 of a function declaration. */
4150 {
4151 /* The type returned by a function or else Standard_Void_Type for a
4152 procedure. */
4154 tree gnu_return_type;
4155 /* The first GCC parameter declaration (a PARM_DECL node). The
4156 PARM_DECL nodes are chained through the DECL_CHAIN field, so this
4157 actually is the head of this parameter list. */
4159 /* Non-null for subprograms containing parameters passed by copy-in
4160 copy-out (Ada In Out or Out parameters not passed by reference),
4161 in which case it is the list of nodes used to specify the values
4162 of the In Out/Out parameters that are returned as a record upon
4163 procedure return. The TREE_PURPOSE of an element of this list is
4164 a field of the record and the TREE_VALUE is the PARM_DECL
4165 corresponding to that field. This list will be saved in the
4166 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
4168 /* List of fields in return type of procedure with copy-in copy-out
4169 parameters. */
4171 /* If an import pragma asks to map this subprogram to a GCC builtin,
4172 this is the builtin DECL node. */
4175 Entity_Id gnat_param;
4176 enum inline_status_t inline_status
4178 ? is_suppressed
4180 ? is_required
4183 /* Subprograms marked both Intrinsic and Always_Inline need not
4184 have a body of their own. */
4185 bool extern_flag
4187 || imported_p
4191 /* The semantics of "pure" in Ada essentially matches that of "const"
4192 in the back-end. In particular, both properties are orthogonal to
4193 the "nothrow" property if the EH circuitry is explicit in the
4194 internal representation of the back-end. If we are to completely
4195 hide the EH circuitry from it, we need to declare that calls to pure
4196 Ada subprograms that can throw have side effects since they can
4197 trigger an "abnormal" transfer of control flow; thus they can be
4198 neither "const" nor "pure" in the back-end sense. */
4199 bool const_flag
4208 /* A parameter may refer to this type, so defer completion of any
4209 incomplete types. */
4211 {
4212 defer_incomplete_level++;
4214 }
4216 /* If the subprogram has an alias, it is probably inherited, so
4217 we can use the original one. If the original "subprogram"
4218 is actually an enumeration literal, it may be the first use
4219 of its type, so we must elaborate that type now. */
4221 {
4227 /* Elaborate any Itypes in the parameters of this entity. */
4235 }
4237 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
4238 corresponding DECL node. Proper generation of calls later on need
4239 proper parameter associations so we don't "break;" here. */
4242 {
4245 /* Inability to find the builtin decl most often indicates a
4246 genuine mistake, but imports of unregistered intrinsics are
4247 sometimes issued on purpose to allow hooking in alternate
4248 bodies. We post a warning conditioned on Wshadow in this case,
4249 to let developers be notified on demand without risking false
4250 positives with common default sets of options. */
4254 }
4256 /* ??? What if we don't find the builtin node above ? warn ? err ?
4257 In the current state we neither warn nor err, and calls will just
4258 be handled as for regular subprograms. */
4260 /* Look into the return type and get its associated GCC tree. If it
4261 is not void, compute various flags for the subprogram type. */
4264 else
4265 {
4266 /* Ada 2012 (AI05-0151): Incomplete types coming from a limited
4267 context may now appear in parameter and result profiles. If
4268 we are only annotating types, break circularities here. */
4272 else
4275 /* If this function returns by reference, make the actual return
4276 type the pointer type and make a note of that. */
4278 {
4281 }
4283 /* If the return type is an unconstrained array type, the return
4284 value will be allocated on the secondary stack so the actual
4285 return type is the fat pointer type. */
4287 {
4290 }
4292 /* Likewise, if the return type requires a transient scope, the
4293 return value will also be allocated on the secondary stack so
4294 the actual return type is the pointer type. */
4296 {
4299 }
4301 /* If the Mechanism is By_Reference, ensure this function uses the
4302 target's by-invisible-reference mechanism, which may not be the
4303 same as above (e.g. it might be passing an extra parameter). */
4308 /* Likewise, if the return type is itself By_Reference. */
4312 /* If the type is a padded type and the underlying type would not
4313 be passed by reference or the function has a foreign convention,
4314 return the underlying type. */
4316 && (!default_pass_by_ref
4321 /* If the return type is unconstrained, that means it must have a
4322 maximum size. Use the padded type as the effective return type.
4323 And ensure the function uses the target's by-invisible-reference
4324 mechanism to avoid copying too much data when it returns. */
4326 {
4329 gnu_return_type
4335 /* Declare it now since it will never be declared otherwise.
4336 This is necessary to ensure that its subtrees are properly
4337 marked. */
4342 gnat_entity);
4345 }
4347 /* If the return type has a size that overflows, we cannot have
4348 a function that returns that type. This usage doesn't make
4349 sense anyway, so give an error here. */
4353 {
4355 gnat_entity);
4361 }
4362 }
4364 /* Loop over the parameters and get their associated GCC tree. While
4365 doing this, build a copy-in copy-out structure if we need one. */
4369 {
4376 /* Ada 2012 (AI05-0151): Incomplete types coming from a limited
4377 context may now appear in parameter and result profiles. If
4378 we are only annotating types, break circularities here. */
4381 {
4384 }
4385 else
4386 {
4389 }
4391 /* Builtins are expanded inline and there is no real call sequence
4392 involved. So the type expected by the underlying expander is
4393 always the type of each argument "as is". */
4396 /* Handle the first parameter of a valued procedure specially. */
4399 /* Otherwise, see if a Mechanism was supplied that forced this
4400 parameter to be passed one way or another. */
4404 ;
4406 {
4410 mech))
4412 else
4414 }
4415 else
4416 {
4419 }
4421 /* Do not call gnat_to_gnu_param for a fake parameter type since
4422 it will try to use the real type again. */
4424 {
4427 else
4428 {
4429 gnu_param
4436 }
4437 }
4438 else
4439 gnu_param
4444 /* We are returned either a PARM_DECL or a type if no parameter
4445 needs to be passed; in either case, adjust the type. */
4448 else
4449 {
4452 }
4454 /* The failure of this assertion will very likely come from an
4455 order of elaboration issue for the type of the parameter. */
4461 {
4467 /* If a parameter is a pointer, this function may modify
4468 memory through it and thus shouldn't be considered
4469 a const function. Also, the memory may be modified
4470 between two calls, so they can't be CSE'ed. The latter
4471 case also handles by-ref parameters. */
4475 }
4478 {
4480 {
4483 /* If this is a function, we also need a field for the
4484 return value to be placed. */
4486 {
4487 gnu_field
4489 gnu_return_type,
4495 gnu_cico_list
4497 }
4501 /* Set a default alignment to speed up accesses. But we
4502 shouldn't increase the size of the structure too much,
4503 lest it doesn't fit in return registers anymore. */
4506 }
4508 gnu_field
4516 gnu_cico_list
4518 }
4519 }
4522 {
4523 /* If we have a CICO list but it has only one entry, we convert
4524 this function into a function that returns this object. */
4528 /* Do not finalize the return type if the subprogram is stubbed
4529 since structures are incomplete for the back-end. */
4531 {
4535 /* Try to promote the mode of the return type if it is passed
4536 in registers, again to speed up accesses. */
4539 NULL_TREE))
4540 {
4541 unsigned int size
4544 machine_mode mode;
4550 {
4558 }
4559 }
4563 }
4564 }
4566 /* Deal with platform-specific calling conventions. */
4568 prepend_one_attribute
4571 gnat_entity);
4573 prepend_one_attribute
4576 gnat_entity);
4578 /* If we should request stack realignment for a foreign convention
4579 subprogram, do so. Note that this applies to task entry points
4580 in particular. */
4583 prepend_one_attribute
4586 gnat_entity);
4588 /* Deal with a pragma Linker_Section on a subprogram. */
4594 /* The lists have been built in reverse. */
4600 || return_by_direct_ref_p
4601 || return_by_invisi_ref_p
4603 gnu_type
4606 return_by_direct_ref_p,
4607 return_by_invisi_ref_p);
4609 /* A procedure (something that doesn't return anything) shouldn't be
4610 considered const since there would be no reason for calling such a
4611 subprogram. Note that procedures with Out (or In Out) parameters
4612 have already been converted into a function with a return type.
4613 Similarly, if the function returns an unconstrained type, then the
4614 function will allocate the return value on the secondary stack and
4615 thus calls to it cannot be CSE'ed, lest the stack be reclaimed. */
4620 {
4621 const int quals
4626 }
4628 /* If we have a builtin decl for that function, use it. Check if the
4629 profiles are compatible and warn if they are not. The checker is
4630 expected to post extra diagnostics in this case. */
4632 {
4633 intrin_binding_t inb;
4640 post_error
4642 gnat_entity);
4647 }
4649 /* If there was no specified Interface_Name and the external and
4650 internal names of the subprogram are the same, only use the
4651 internal name to allow disambiguation of nested subprograms. */
4656 /* If we are defining the subprogram and it has an Address clause
4657 we must get the address expression from the saved GCC tree for the
4658 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4659 the address expression here since the front-end has guaranteed
4660 in that case that the elaboration has no effects. If there is
4661 an Address clause and we are not defining the object, just
4662 make it a constant. */
4664 {
4668 gnu_address
4675 /* Convert the type of the object to a reference type that can
4676 alias everything as per 13.3(19). */
4677 gnu_type
4682 gnu_decl
4687 }
4690 {
4692 gnu_decl
4695 }
4696 else
4697 {
4698 gnu_decl
4703 /* This is unrelated to the stub built right above. */
4706 }
4707 }
4718 {
4719 /* Get the "full view" of this entity. If this is an incomplete
4720 entity from a limited with, treat its non-limited view as the
4721 full view. Otherwise, use either the full view or the underlying
4722 full view, whichever is present. This is used in all the tests
4723 below. */
4724 Entity_Id full_view
4733 /* If this is an incomplete type with no full view, it must be a Taft
4734 Amendment type, in which case we return a dummy type. Otherwise,
4735 just get the type from its Etype. */
4737 {
4739 {
4742 }
4743 else
4744 {
4748 }
4750 }
4752 /* If we already made a type for the full view, reuse it. */
4754 {
4757 }
4759 /* Otherwise, if we are not defining the type now, get the type
4760 from the full view. But always get the type from the full view
4761 for define on use types, since otherwise we won't see them! */
4765 {
4769 }
4771 /* For incomplete types, make a dummy type entry which will be
4772 replaced later. Save it as the full declaration's type so
4773 we can do any needed updates when we see it. */
4780 }
4783 /* Class-wide types are always transformed into their root type. */
4792 /* Concurrent types are always transformed into their record type. */
4795 else
4806 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4807 we've already saved it, so we don't try to. */
4813 /* This is a SPARK annotation that only reaches here when compiling in
4814 ASIS mode. */
4822 }
4824 /* If we had a case where we evaluated another type and it might have
4825 defined this one, handle it here. */
4827 {
4830 }
4832 /* If we are processing a type and there is either no decl for it or
4833 we just made one, do some common processing for the type, such as
4834 handling alignment and possible padding. */
4836 {
4837 /* Process the attributes, if not already done. Note that the type is
4838 already defined so we cannot pass true for IN_PLACE here. */
4841 /* Tell the middle-end that objects of tagged types are guaranteed to
4842 be properly aligned. This is necessary because conversions to the
4843 class-wide type are translated into conversions to the root type,
4844 which can be less aligned than some of its derived types. */
4849 /* Record whether the type is passed by reference. */
4853 /* ??? Don't set the size for a String_Literal since it is either
4854 confirming or we don't handle it properly (if the low bound is
4855 non-constant). */
4857 {
4860 gnu_size
4863 }
4865 /* If a size was specified, see if we can make a new type of that size
4866 by rearranging the type, for example from a fat to a thin pointer. */
4868 {
4869 gnu_type
4876 }
4878 /* If the alignment has not already been processed and this is not
4879 an unconstrained array type, see if an alignment is specified.
4880 If not, we pick a default alignment for atomic objects. */
4882 ;
4884 {
4888 /* Warn on suspiciously large alignments. This should catch
4889 errors about the (alignment,byte)/(size,bit) discrepancy. */
4891 {
4892 tree size;
4894 /* If a size was specified, take it into account. Otherwise
4895 use the RM size for records or unions as the type size has
4896 already been adjusted to the alignment. */
4902 else
4905 /* Consider an alignment as suspicious if the alignment/size
4906 ratio is greater or equal to the byte/bit ratio. */
4911 gnat_entity);
4912 }
4913 }
4924 /* See if we need to pad the type. If we did, and made a record,
4925 the name of the new type may be changed. So get it back for
4926 us when we make the new TYPE_DECL below. */
4934 /* Now set the RM size of the type. We cannot do it before padding
4935 because we need to accept arbitrary RM sizes on integral types. */
4938 /* If we are at global level, GCC will have applied variable_size to
4939 the type, but that won't have done anything. So, if it's not
4940 a constant or self-referential, call elaborate_expression_1 to
4941 make a variable for the size rather than calculating it each time.
4942 Handle both the RM size and the actual size. */
4947 {
4955 /* ??? For now, store the size as a multiple of the alignment in
4956 bytes so that we can see the alignment from the tree. */
4963 /* ??? gnu_type may come from an existing type so the MULT_EXPR node
4964 may not be marked by the call to create_type_decl below. */
4968 {
4973 {
4977 /* If the position of the variant part is constant, subtract
4978 it from the size of the type of the parent to get the new
4979 size. This manual CSE reduces the data size. */
4981 {
4989 }
4990 else
4991 {
4994 gnat_entity,
4998 /* ??? For now, store the size as a multiple of the
4999 alignment in bytes so that we can see the alignment
5000 from the tree. */
5003 gnat_entity,
5004 get_identifier
5009 /* ??? For now, store the offset as a multiple of the
5010 alignment in bytes so that we can see the alignment
5011 from the tree. */
5014 gnat_entity,
5017 DECL_OFFSET_ALIGN
5019 }
5023 }
5027 else
5028 ada_size
5033 }
5034 }
5036 /* If this is a record type or subtype, call elaborate_expression_2 on
5037 any field position. Do this for both global and local types.
5038 Skip any fields that we haven't made trees for to avoid problems with
5039 class wide types. */
5044 {
5047 /* ??? For now, store the offset as a multiple of the alignment
5048 in bytes so that we can see the alignment from the tree. */
5050 {
5053 gnat_temp,
5058 /* ??? The context of gnu_field is not necessarily gnu_type
5059 so the MULT_EXPR node built above may not be marked by
5060 the call to create_type_decl below. */
5063 }
5064 }
5069 /* If this is not an unconstrained array type, set some flags. */
5071 {
5080 }
5086 else
5087 {
5090 }
5091 }
5094 {
5097 /* If this is a derived type, relate its alias set to that of its parent
5098 to avoid troubles when a call to an inherited primitive is inlined in
5099 a context where a derived object is accessed. The inlined code works
5100 on the parent view so the resulting code may access the same object
5101 using both the parent and the derived alias sets, which thus have to
5102 conflict. As the same issue arises with component references, the
5103 parent alias set also has to conflict with composite types enclosing
5104 derived components. For instance, if we have:
5106 type D is new T;
5107 type R is record
5108 Component : D;
5109 end record;
5111 we want T to conflict with both D and R, in addition to R being a
5112 superset of D by record/component construction.
5114 One way to achieve this is to perform an alias set copy from the
5115 parent to the derived type. This is not quite appropriate, though,
5116 as we don't want separate derived types to conflict with each other:
5118 type I1 is new Integer;
5119 type I2 is new Integer;
5121 We want I1 and I2 to both conflict with Integer but we do not want
5122 I1 to conflict with I2, and an alias set copy on derivation would
5123 have that effect.
5125 The option chosen is to make the alias set of the derived type a
5126 superset of that of its parent type. It trivially fulfills the
5127 simple requirement for the Integer derivation example above, and
5128 the component case as well by superset transitivity:
5130 superset superset
5131 R ----------> D ----------> T
5133 However, for composite types, conversions between derived types are
5134 translated into VIEW_CONVERT_EXPRs so a sequence like:
5136 type Comp1 is new Comp;
5137 type Comp2 is new Comp;
5138 procedure Proc (C : Comp1);
5140 C : Comp2;
5141 Proc (Comp1 (C));
5143 is translated into:
5145 C : Comp2;
5146 Proc ((Comp1 &) &VIEW_CONVERT_EXPR <Comp1> (C));
5148 and gimplified into:
5150 C : Comp2;
5151 Comp1 *C.0;
5152 C.0 = (Comp1 *) &C;
5153 Proc (C.0);
5155 i.e. generates code involving type punning. Therefore, Comp1 needs
5156 to conflict with Comp2 and an alias set copy is required.
5158 The language rules ensure the parent type is already frozen here. */
5162 {
5164 /* For constrained packed array subtypes, the implementation type is
5165 used instead of the nominal type. */
5173 }
5175 /* Back-annotate the Alignment of the type if not already in the
5176 tree. Likewise for sizes. */
5178 {
5182 /* If the default alignment of "double" or larger scalar types is
5183 specifically capped and this is not an array with an alignment
5184 clause on the component type, return the cap. */
5186 is_capped_double
5189 is_capped_double
5191 else
5196 else
5200 }
5203 {
5206 /* If the size is self-referential, annotate the maximum value. */
5210 /* If we are just annotating types and the type is tagged, the tag
5211 and the parent components are not generated by the front-end so
5212 sizes must be adjusted if there is no representation clause. */
5218 {
5220 Uint uint_size;
5223 {
5227 }
5228 else
5232 offset
5240 }
5241 else
5243 }
5247 }
5249 /* If we really have a ..._DECL node, set a couple of flags on it. But we
5250 cannot do so if we are reusing the ..._DECL node made for an equivalent
5251 type or an alias or a renamed object as the predicates don't apply to it
5252 but to GNAT_ENTITY. */
5257 {
5263 }
5265 /* If we haven't already, associate the ..._DECL node that we just made with
5266 the input GNAT entity node. */
5270 /* Now we are sure gnat_entity has a corresponding ..._DECL node,
5271 eliminate as many deferred computations as possible. */
5274 /* If this is an enumeration or floating-point type, we were not able to set
5275 the bounds since they refer to the type. These are always static. */
5278 {
5282 /* If this is a padded type, we need to use the underlying type. */
5286 /* If this is a floating point type and we haven't set a floating
5287 point type yet, use this in the evaluation of the bounds. */
5295 {
5296 /* Enumeration types have specific RM bounds. */
5299 }
5300 else
5301 {
5302 /* Floating-point types don't have specific RM bounds. */
5305 }
5306 }
5308 /* If we deferred processing of incomplete types, re-enable it. If there
5309 were no other disables and we have deferred types to process, do so. */
5313 {
5316 /* We are back to level 0 for the deferring of incomplete types.
5317 But processing these incomplete types below may itself require
5318 deferring, so preserve what we have and restart from scratch. */
5323 {
5330 }
5331 }
5333 /* If we are not defining this type, see if it's on one of the lists of
5334 incomplete types. If so, handle the list entry now. */
5336 {
5341 {
5345 }
5349 {
5353 }
5354 }
5357 force_global--;
5359 /* If this is a packed array type whose original array type is itself
5360 an Itype without freeze node, make sure the latter is processed. */
5368 }
5370 /* Similar, but if the returned value is a COMPONENT_REF, return the
5371 FIELD_DECL. */
5373 tree
5375 {
5382 }
5384 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5385 the GCC type corresponding to that entity. */
5387 tree
5389 {
5390 tree gnu_decl;
5392 /* The back end never attempts to annotate generic types. */
5400 }
5402 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5403 the unpadded version of the GCC type corresponding to that entity. */
5405 tree
5407 {
5414 }
5416 /* Return the DECL associated with the public subprogram GNAT_ENTITY but whose
5417 type has been changed to that of the parameterless procedure, except if an
5418 alias is already present, in which case it is returned instead. */
5420 tree
5422 {
5426 /* See the E_Function/E_Procedure case of gnat_to_gnu_entity for the model
5427 of the handling applied here. */
5430 {
5434 }
5442 gnat_entity);
5446 gnat_entity);
5451 return
5454 }
5456 /* Return whether the E_Subprogram_Type/E_Function/E_Procedure GNAT_ENTITY is
5457 a C++ imported method or equivalent.
5459 We use the predicate on 32-bit x86/Windows to find out whether we need to
5460 use the "thiscall" calling convention for GNAT_ENTITY. This convention is
5461 used for C++ methods (functions with METHOD_TYPE) by the back-end. */
5463 bool
5465 {
5469 /* This is the main case: C++ method imported as a primitive operation.
5470 Note that a C++ class with no virtual functions can be imported as a
5471 limited record type so the operation is not necessarily dispatching. */
5475 /* A thunk needs to be handled like its associated primitive operation. */
5479 /* A constructor is a method on the C++ side. */
5483 /* This is set on the E_Subprogram_Type built for a dispatching call. */
5488 }
5490 /* Finalize the processing of From_Limited_With incomplete types. */
5492 void
5494 {
5501 {
5508 }
5509 }
5511 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
5512 kind of type (such E_Task_Type) that has a different type which Gigi
5513 uses for its representation. If the type does not have a special type
5514 for its representation, return GNAT_ENTITY. If a type is supposed to
5515 exist, but does not, abort unless annotating types, in which case
5516 return Empty. If GNAT_ENTITY is Empty, return Empty. */
5518 Entity_Id
5520 {
5527 {
5551 }
5556 }
5558 /* Return a GCC tree for a type corresponding to the component type of the
5559 array type or subtype GNAT_ARRAY. DEFINITION is true if this component
5560 is for an array being defined. DEBUG_INFO_P is true if we need to write
5561 debug information for other types that we may create in the process. */
5563 static tree
5566 {
5569 tree gnu_comp_size;
5571 /* Try to get a smaller form of the component if needed. */
5585 /* Get and validate any specified Component_Size. */
5586 gnu_comp_size
5591 /* If the array has aliased components and the component size can be zero,
5592 force at least unit size to ensure that the components have distinct
5593 addresses. */
5599 gnu_comp_size
5602 /* If the component type is a RECORD_TYPE that has a self-referential size,
5603 then use the maximum size for the component size. */
5609 /* Honor the component size. This is not needed for bit-packed arrays. */
5611 {
5615 /* If an alignment is specified, use it as a cap on the component type
5616 so that it can be honored for the whole type. But ignore it for the
5617 original type of packed array types. */
5621 else
5627 else
5633 /* If a padding record was made, declare it now since it will never be
5634 declared otherwise. This is necessary to ensure that its subtrees
5635 are properly marked. */
5638 gnat_array);
5639 }
5641 /* If the component type is a padded type made for a non-bit-packed array
5642 of scalars with reverse storage order, we need to propagate the reverse
5643 storage order to the padding type since it is the innermost enclosing
5644 aggregate type around the scalar. */
5655 }
5657 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
5658 using MECH as its passing mechanism, to be placed in the parameter
5659 list built for GNAT_SUBPROG. Assume a foreign convention for the
5660 latter if FOREIGN is true. Also set CICO to true if the parameter
5661 must use the copy-in copy-out implementation mechanism.
5663 The returned tree is a PARM_DECL, except for those cases where no
5664 parameter needs to be actually passed to the subprogram; the type
5665 of this "shadow" parameter is then returned instead. */
5667 static tree
5670 {
5674 /* The parameter can be indirectly modified if its address is taken. */
5678 tree gnu_param;
5680 /* Copy-return is used only for the first parameter of a valued procedure.
5681 It's a copy mechanism for which a parameter is never allocated. */
5683 {
5687 }
5689 /* If this is either a foreign function or if the underlying type won't
5690 be passed by reference and is as aligned as the original type, strip
5691 off possible padding type. */
5693 {
5702 }
5704 /* If this is a read-only parameter, make a variant of the type that is
5705 read-only. ??? However, if this is an unconstrained array, that type
5706 can be very complex, so skip it for now. Likewise for any other
5707 self-referential type. */
5713 /* For foreign conventions, pass arrays as pointers to the element type.
5714 First check for unconstrained array and get the underlying array. */
5716 gnu_param_type
5719 /* For GCC builtins, pass Address integer types as (void *) */
5725 /* Arrays are passed as pointers to element type for foreign conventions. */
5727 {
5728 /* Strip off any multi-dimensional entries, then strip
5729 off the last array to get the component type. */
5738 gnu_param_type
5742 }
5744 /* Fat pointers are passed as thin pointers for foreign conventions. */
5746 gnu_param_type
5749 /* If we must pass or were requested to pass by reference, do so.
5750 If we were requested to pass by copy, do so.
5751 Otherwise, for foreign conventions, pass In Out or Out parameters
5752 or aggregates by reference. For COBOL and Fortran, pass all
5753 integer and FP types that way too. For Convention Ada, use
5754 the standard Ada default. */
5758 && ((foreign
5760 || (foreign
5765 || (!foreign
5767 {
5768 /* We take advantage of 6.2(12) by considering that references built for
5769 parameters whose type isn't by-ref and for which the mechanism hasn't
5770 been forced to by-ref are restrict-qualified in the C sense. */
5771 bool restrict_p
5775 gnu_param_type
5778 }
5780 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
5787 /* If this is an Out parameter that isn't passed by reference and isn't
5788 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
5789 it will be a VAR_DECL created when we process the procedure, so just
5790 return its type. For the special parameter of a valued procedure,
5791 never pass it in.
5793 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
5794 Out parameters with discriminants or implicit initial values to be
5795 handled like In Out parameters. These type are normally built as
5796 aggregates, hence passed by reference, except for some packed arrays
5797 which end up encoded in special integer types. Note that scalars can
5798 be given implicit initial values using the Default_Value aspect.
5800 The exception we need to make is then for packed arrays of records
5801 with discriminants or implicit initial values. We have no light/easy
5802 way to check for the latter case, so we merely check for packed arrays
5803 of records. This may lead to useless copy-in operations, but in very
5804 rare cases only, as these would be exceptions in a set of already
5805 exceptional situations. */
5807 && !by_ref
5808 && (by_return
5825 /* If no Mechanism was specified, indicate what we're using, then
5826 back-annotate it. */
5832 }
5834 /* Return true if GNAT_ENTITY is an incomplete entity coming from a limited
5835 with of the main unit and whose full view has not been elaborated yet. */
5837 static bool
5839 {
5840 /* Class-wide types are always transformed into their root type. */
5846 {
5853 }
5856 }
5858 /* Like build_qualified_type, but TYPE_QUALS is added to the existing
5859 qualifiers on TYPE. */
5861 static tree
5863 {
5865 }
5867 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
5869 static bool
5871 {
5878 return
5880 }
5882 /* Return true if the array type GNU_TYPE, which represents a dimension of
5883 GNAT_TYPE, has a non-aliased component in the back-end sense. */
5885 static bool
5887 {
5888 /* If the array type is not the innermost dimension of the GNAT type,
5889 then it has a non-aliased component. */
5894 /* If the array type has an aliased component in the front-end sense,
5895 then it also has an aliased component in the back-end sense. */
5899 /* If this is a derived type, then it has a non-aliased component if
5900 and only if its parent type also has one. */
5902 {
5906 gnu_parent_type
5911 }
5913 /* Otherwise, rely exclusively on properties of the element type. */
5915 }
5917 /* Return true if GNAT_ADDRESS is a value known at compile-time. */
5919 static bool
5921 {
5922 /* Catch System'To_Address. */
5927 }
5929 /* Return true if GNAT_RANGE, a N_Range node, cannot be superflat, i.e. if the
5930 inequality HB >= LB-1 is true. LB and HB are the low and high bounds. */
5932 static bool
5934 {
5936 Node_Id scalar_range;
5939 /* If the low bound is not constant, try to find an upper bound. */
5948 /* If the high bound is not constant, try to find a lower bound. */
5957 /* If we have failed to find constant bounds, punt. */
5962 /* We need at least a signed 64-bit type to catch most cases. */
5968 /* If the low bound is the smallest integer, nothing can be smaller. */
5974 }
5976 /* Return true if GNU_EXPR is (essentially) the address of a CONSTRUCTOR. */
5978 static bool
5980 {
5988 }
5989 \f
5990 /* Given GNAT_ENTITY, elaborate all expressions that are required to
5991 be elaborated at the point of its definition, but do nothing else. */
5993 void
5995 {
5997 {
6004 {
6008 /* ??? Tests to avoid Constraint_Error in static expressions
6009 are needed until after the front stops generating bogus
6010 conversions on bounds of real types. */
6018 }
6025 {
6026 Node_Id gnat_discriminant_expr;
6027 Entity_Id gnat_field;
6031 gnat_discriminant_expr
6036 /* Ignore access discriminants. */
6041 }
6044 }
6045 }
6046 \f
6047 /* Return true if the size in units represented by GNU_SIZE can be handled by
6048 an allocation. If STATIC_P is true, consider only what can be done with a
6049 static allocation. */
6051 static bool
6053 {
6054 /* We can allocate a fixed size if it is a valid for the middle-end. */
6058 /* We can allocate a variable size if this isn't a static allocation. */
6059 else
6061 }
6062 \f
6063 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
6064 NAME, ARGS and ERROR_POINT. */
6066 static void
6069 tree attr_name,
6070 tree attr_args,
6071 Node_Id attr_error_point)
6072 {
6082 }
6084 /* Prepend to ATTR_LIST an entry for an attribute provided by GNAT_PRAGMA. */
6086 static void
6088 {
6093 /* Map the pragma at hand. Skip if this isn't one we know how to handle. */
6095 {
6126 }
6128 /* See what arguments we have and turn them into GCC trees for attribute
6129 handlers. These expect identifier for strings. We handle at most two
6130 arguments and static expressions only. */
6132 {
6138 {
6142 {
6146 }
6149 }
6153 {
6158 }
6159 }
6161 /* Prepend to the list. Make a list of the argument we might have, as GCC
6162 expects it. */
6164 gnu_arg1
6168 }
6170 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
6172 static void
6174 {
6175 Node_Id gnat_temp;
6177 /* Attributes are stored as Representation Item pragmas. */
6183 }
6184 \f
6185 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
6186 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
6187 return the GCC tree to use for that expression. GNU_NAME is the suffix
6188 to use if a variable needs to be created and DEFINITION is true if this
6189 is a definition of GNAT_ENTITY. If NEED_VALUE is true, we need a result;
6190 otherwise, we are just elaborating the expression for side-effects. If
6191 NEED_DEBUG is true, we need a variable for debugging purposes even if it
6192 isn't needed for code generation. */
6194 static tree
6197 {
6198 tree gnu_expr;
6200 /* If we already elaborated this expression (e.g. it was involved
6201 in the definition of a private type), use the old value. */
6205 /* If we don't need a value and this is static or a discriminant,
6206 we don't need to do anything. */
6213 /* If it's a static expression, we don't need a variable for debugging. */
6217 /* Otherwise, convert this tree to its GCC equivalent and elaborate it. */
6221 /* Save the expression in case we try to elaborate this entity again. Since
6222 it's not a DECL, don't check it. Don't save if it's a discriminant. */
6227 }
6229 /* Similar, but take a GNU expression and always return a result. */
6231 static tree
6234 {
6239 /* In most cases, we won't see a naked FIELD_DECL because a discriminant
6240 reference will have been replaced with a COMPONENT_REF when the type
6241 is being elaborated. However, there are some cases involving child
6242 types where we will. So convert it to a COMPONENT_REF. We hope it
6243 will be at the highest level of the expression in these cases. */
6249 /* If GNU_EXPR contains a placeholder, just return it. We rely on the fact
6250 that an expression cannot contain both a discriminant and a variable. */
6254 /* If GNU_EXPR is neither a constant nor based on a read-only variable, make
6255 a variable that is initialized to contain the expression when the package
6256 containing the definition is elaborated. If this entity is defined at top
6257 level, replace the expression by the variable; otherwise use a SAVE_EXPR
6258 if this is necessary. */
6261 else
6262 {
6263 /* Skip any conversions and simple constant arithmetics to see if the
6264 expression is based on a read-only variable.
6265 ??? This really should remain read-only, but we have to think about
6266 the typing of the tree here. */
6272 {
6274 tree offset;
6275 machine_mode mode;
6278 inner
6281 /* If the offset is variable, err on the side of caution. */
6284 }
6286 expr_variable_p
6287 = !(inner
6290 }
6292 /* We only need to use the variable if we are in a global context since GCC
6293 can do the right thing in the local case. However, when not optimizing,
6294 use it for bounds of loop iteration scheme to avoid code duplication. */
6295 use_variable = expr_variable_p
6296 && (expr_global_p
6297 || (!optimize
6298 && definition
6303 /* Now create it, possibly only for debugging purposes. */
6305 {
6306 /* The following variable creation can happen when processing the body of
6307 subprograms that are defined out of the extended main unit and
6308 inlined. In this case, we are not at the global scope, and thus the
6309 new variable must not be tagged "external", as we used to do here as
6310 long as definition == 0. */
6312 tree gnu_decl
6313 = create_var_decl_1
6320 /* Using this variable at debug time (if need_debug is true) requires a
6321 proper location. The back-end will compute a location for this
6322 variable only if the variable is used by the generated code.
6323 Returning the variable ensures the caller will use it in generated
6324 code. Note that there is no need for a location if the debug info
6325 contains an integer constant.
6326 FIXME: when the encoding-based debug scheme is dropped, move this
6327 condition to the top-level IF block: we will not need to create a
6328 variable anymore in such cases, then. */
6331 }
6334 }
6336 /* Similar, but take an alignment factor and make it explicit in the tree. */
6338 static tree
6341 {
6343 return
6346 gnu_expr,
6347 unit_align),
6349 need_debug),
6350 unit_align);
6351 }
6352 \f
6353 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
6354 the value passed against the list of choices. */
6356 tree
6358 {
6359 Node_Id choice;
6360 Node_Id gnat_temp;
6365 {
6367 {
6372 this_test
6386 this_test
6396 /* This represents either a subtype range, an enumeration
6397 literal, or a constant Ekind says which. If an enumeration
6398 literal or constant, fall through to the next case. */
6401 {
6407 this_test
6414 }
6416 /* ... fall through ... */
6422 single);
6431 }
6434 this_test);
6435 }
6438 }
6439 \f
6440 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
6441 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
6443 static int
6445 {
6446 /* If the field contains an item of variable size, we cannot pack it
6447 because we cannot create temporaries of non-fixed size in case
6448 we need to take the address of the field. See addressable_p and
6449 the notes on the addressability issues for further details. */
6453 /* If the alignment of the record is specified and the field type
6454 is over-aligned, request Storage_Unit alignment for the field. */
6456 {
6459 else
6461 }
6464 }
6466 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
6467 placed in GNU_RECORD_TYPE.
6469 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
6470 record has Component_Alignment of Storage_Unit, -2 if the enclosing
6471 record has a specified alignment.
6473 DEFINITION is true if this field is for a record being defined.
6475 DEBUG_INFO_P is true if we need to write debug information for types
6476 that we may create in the process. */
6478 static tree
6481 {
6483 const bool is_aliased
6485 const bool is_atomic
6487 const bool is_independent
6489 const bool is_volatile
6491 const bool needs_strict_alignment
6492 = (is_aliased
6493 || is_independent
6494 || is_volatile
6500 /* If this field requires strict alignment, we cannot pack it because
6501 it would very likely be under-aligned in the record. */
6504 else
6507 /* If a size is specified, use it. Otherwise, if the record type is packed,
6508 use the official RM size. See "Handling of Type'Size Values" in Einfo
6509 for further details. */
6516 else
6519 /* If we have a specified size that is smaller than that of the field's type,
6520 or a position is specified, and the field's type is a record that doesn't
6521 require strict alignment, see if we can get either an integral mode form
6522 of the type or a smaller form. If we can, show a size was specified for
6523 the field if there wasn't one already, so we know to make this a bitfield
6524 and avoid making things wider.
6526 Changing to an integral mode form is useful when the record is packed as
6527 we can then place the field at a non-byte-aligned position and so achieve
6528 tighter packing. This is in addition required if the field shares a byte
6529 with another field and the front-end lets the back-end handle the access
6530 to the field, because GCC cannot handle non-byte-aligned BLKmode fields.
6532 Changing to a smaller form is required if the specified size is smaller
6533 than that of the field's type and the type contains sub-fields that are
6534 padded, in order to avoid generating accesses to these sub-fields that
6535 are wider than the field.
6537 We avoid the transformation if it is not required or potentially useful,
6538 as it might entail an increase of the field's alignment and have ripple
6539 effects on the outer record type. A typical case is a field known to be
6540 byte-aligned and not to share a byte with another field. */
6546 || (gnu_size
6552 {
6555 {
6559 }
6560 }
6566 {
6568 Entity_Id gnat_parent
6575 /* Ensure the position does not overlap with the parent subtype, if there
6576 is one. This test is omitted if the parent of the tagged type has a
6577 full rep clause since, in this case, component clauses are allowed to
6578 overlay the space allocated for the parent type and the front-end has
6579 checked that there are no overlapping components. */
6581 {
6586 post_error_ne_tree
6589 }
6591 /* If this field needs strict alignment, make sure that the record is
6592 sufficiently aligned and that the position and size are consistent
6593 with the type. But don't do it if we are just annotating types and
6594 the field's type is tagged, since tagged types aren't fully laid out
6595 in this mode. Also, note that atomic implies volatile so the inner
6596 test sequences ordering is significant here. */
6599 {
6605 /* If the position is not a multiple of the alignment of the type,
6606 then error out and reset the position. */
6609 {
6623 else
6627 type_align);
6629 }
6632 {
6636 /* If the size is lower than that of the type, or greater for
6637 atomic and aliased, then error out and reset the size. */
6639 {
6653 else
6657 gnu_type_size);
6659 }
6661 /* Likewise if the size is not a multiple of a byte, */
6663 bitsize_unit_node)))
6664 {
6676 else
6681 }
6682 }
6683 }
6684 }
6686 /* If the record has rep clauses and this is the tag field, make a rep
6687 clause for it as well. */
6690 {
6693 }
6695 else
6696 {
6699 /* If we are packing the record and the field is BLKmode, round the
6700 size up to a byte boundary. */
6703 }
6705 /* We need to make the size the maximum for the type if it is
6706 self-referential and an unconstrained type. In that case, we can't
6707 pack the field since we can't make a copy to align it. */
6709 && !gnu_size
6712 {
6715 }
6717 /* If a size is specified, adjust the field's type to it. */
6719 {
6720 tree orig_field_type;
6722 /* If the field's type is justified modular, we would need to remove
6723 the wrapper to (better) meet the layout requirements. However we
6724 can do so only if the field is not aliased to preserve the unique
6725 layout and if the prescribed size is not greater than that of the
6726 packed array to preserve the justification. */
6734 /* Similarly if the field's type is a misaligned integral type, but
6735 there is no restriction on the size as there is no justification. */
6741 gnu_field_type
6749 /* If a padding record was made, declare it now since it will never be
6750 declared otherwise. This is necessary to ensure that its subtrees
6751 are properly marked. */
6756 }
6758 /* Otherwise (or if there was an error), don't specify a position. */
6759 else
6762 /* If the field's type is a padded type made for a scalar field of a record
6763 type with reverse storage order, we need to propagate the reverse storage
6764 order to the padding type since it is the innermost enclosing aggregate
6765 type around the scalar. */
6774 /* Now create the decl for the field. */
6775 gnu_field
6787 }
6788 \f
6789 /* Return true if at least one member of COMPONENT_LIST needs strict
6790 alignment. */
6792 static bool
6794 {
6795 Node_Id component_decl;
6800 {
6808 }
6811 }
6813 /* Return true if TYPE is a type with variable size or a padding type with a
6814 field of variable size or a record that has a field with such a type. */
6816 static bool
6818 {
6819 tree field;
6836 }
6837 \f
6838 /* Return true if FIELD is an artificial field. */
6840 static bool
6842 {
6843 /* These fields are generated by the front-end proper. */
6847 /* These fields are generated by gigi. */
6852 }
6854 /* Return true if FIELD is a non-artificial aliased field. */
6856 static bool
6858 {
6863 }
6865 /* Return true if FIELD is a non-artificial field with self-referential
6866 size. */
6868 static bool
6870 {
6878 }
6880 /* Return true if FIELD is a non-artificial field with variable size. */
6882 static bool
6884 {
6892 }
6894 /* qsort comparer for the bit positions of two record components. */
6896 static int
6898 {
6901 const int ret
6905 }
6907 /* Structure holding information for a given variant. */
6909 {
6910 /* The record type of the variant. */
6911 tree type;
6913 /* The name of the variant. */
6914 tree name;
6916 /* The qualifier of the variant. */
6917 tree qual;
6919 /* Whether the variant has a rep clause. */
6922 /* Whether the variant is packed. */
6927 /* Translate and chain the GNAT_COMPONENT_LIST to the GNU_FIELD_LIST, set the
6928 result as the field list of GNU_RECORD_TYPE and finish it up. Return true
6929 if GNU_RECORD_TYPE has a rep clause which affects the layout (see below).
6930 When called from gnat_to_gnu_entity during the processing of a record type
6931 definition, the GCC node for the parent, if any, will be the single field
6932 of GNU_RECORD_TYPE and the GCC nodes for the discriminants will be on the
6933 GNU_FIELD_LIST. The other calls to this function are recursive calls for
6934 the component list of a variant and, in this case, GNU_FIELD_LIST is empty.
6936 PACKED is 1 if this is for a packed record, -1 if this is for a record
6937 with Component_Alignment of Storage_Unit, -2 if this is for a record
6938 with a specified alignment.
6940 DEFINITION is true if we are defining this record type.
6942 CANCEL_ALIGNMENT is true if the alignment should be zeroed before laying
6943 out the record. This means the alignment only serves to force fields to
6944 be bitfields, but not to require the record to be that aligned. This is
6945 used for variants.
6947 ALL_REP is true if a rep clause is present for all the fields.
6949 UNCHECKED_UNION is true if we are building this type for a record with a
6950 Pragma Unchecked_Union.
6952 ARTIFICIAL is true if this is a type that was generated by the compiler.
6954 DEBUG_INFO is true if we need to write debug information about the type.
6956 MAYBE_UNUSED is true if this type may be unused in the end; this doesn't
6957 mean that its contents may be unused as well, only the container itself.
6959 REORDER is true if we are permitted to reorder components of this type.
6961 FIRST_FREE_POS, if nonzero, is the first (lowest) free field position in
6962 the outer record type down to this variant level. It is nonzero only if
6963 all the fields down to this level have a rep clause and ALL_REP is false.
6965 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
6966 with a rep clause is to be added; in this case, that is all that should
6967 be done with such fields and the return value will be false. */
6969 static bool
6976 {
6990 /* For each component referenced in a component declaration create a GCC
6991 field and add it to the list, skipping pragmas in the GNAT list. */
6998 {
7002 /* If present, the _Parent field must have been created as the single
7003 field of the record type. Put it before any other fields. */
7005 {
7008 }
7009 else
7010 {
7014 /* If this is the _Tag field, put it before any other fields. */
7018 /* If this is the _Controller field, put it before the other
7019 fields except for the _Tag or _Parent field. */
7021 {
7024 }
7026 /* If this is a regular field, put it after the other fields. */
7027 else
7028 {
7034 /* And record information for the final layout. */
7039 }
7040 }
7043 }
7045 /* At the end of the component list there may be a variant part. */
7048 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
7049 mutually exclusive and should go in the same memory. To do this we need
7050 to treat each variant as a record whose elements are created from the
7051 component list for the variant. So here we create the records from the
7052 lists for the variants and put them all into the QUAL_UNION_TYPE.
7053 If this is an Unchecked_Union, we make a UNION_TYPE instead or
7054 use GNU_RECORD_TYPE if there are no fields so far. */
7056 {
7060 tree gnu_var_name
7071 gnu_union_name
7074 /* Reuse the enclosing union if this is an Unchecked_Union whose fields
7075 are all in the variant part, to match the layout of C unions. There
7076 is an associated check below. */
7079 else
7080 {
7081 gnu_union_type
7089 }
7091 /* If all the fields down to this level have a rep clause, find out
7092 whether all the fields at this level also have one. If so, then
7093 compute the new first free position to be passed downward. */
7096 {
7098 gnu_field;
7101 {
7104 this_first_free_pos
7106 }
7107 else
7108 {
7111 }
7112 }
7114 /* We build the variants in two passes. The bulk of the work is done in
7115 the first pass, that is to say translating the GNAT nodes, building
7116 the container types and computing the associated properties. However
7117 we cannot finish up the container types during this pass because we
7118 don't know where the variant part will be placed until the end. */
7122 {
7127 vinfo_t vinfo;
7135 /* Set the alignment of the inner type in case we need to make
7136 inner objects into bitfields, but then clear it out so the
7137 record actually gets only the alignment required. */
7143 /* Similarly, if the outer record has a size specified and all
7144 the fields have a rep clause, we can propagate the size. */
7146 {
7150 }
7152 /* Add the fields into the record type for the variant. Note that
7153 we aren't sure to really use it at this point, see below. */
7154 has_rep
7158 unchecked_union,
7160 this_first_free_pos,
7161 all_rep || this_first_free_pos
7164 /* Translate the qualifier and annotate the GNAT node. */
7168 /* Deal with packedness like in gnat_to_gnu_field. */
7170 {
7173 }
7174 else
7175 field_packed
7178 /* Push this variant onto the stack for the second pass. */
7186 /* Compute the global properties that will determine the placement of
7187 the variant part. */
7191 }
7193 /* Round up the first free position to the alignment of the variant part
7194 for the variants without rep clause. This will guarantee a consistent
7195 layout independently of the placement of the variant part. */
7199 /* In the second pass, the container types are adjusted if necessary and
7200 finished up, then the corresponding fields of the variant part are
7201 built with their qualifier, unless this is an unchecked union. */
7203 {
7207 /* If this is an Unchecked_Union whose fields are all in the variant
7208 part and we have a single field with no representation clause or
7209 placed at offset zero, use the field directly to match the layout
7210 of C unions. */
7212 && gnu_field_list
7216 {
7219 }
7220 else
7221 {
7222 /* Finalize the variant type now. We used to throw away empty
7223 record types but we no longer do that because we need them to
7224 generate complete debug info for the variant; otherwise, the
7225 union type definition will be lacking the fields associated
7226 with these empty variants. */
7228 {
7229 /* The variant part will be at offset 0 so we need to ensure
7230 that the fields are laid out starting from the first free
7231 position at this level. */
7233 tree gnu_rep_part;
7237 gnu_rep_part
7239 this_first_free_pos);
7244 }
7251 gnu_field
7253 gnu_union_type,
7254 all_rep_and_size
7263 }
7267 }
7269 /* Only make the QUAL_UNION_TYPE if there are non-empty variants. */
7271 {
7275 {
7279 }
7284 /* If GNU_UNION_TYPE is our record type, it means we must have an
7285 Unchecked_Union with no fields. Verify that and, if so, just
7286 return. */
7288 {
7290 && !gnu_field_list
7293 }
7298 /* Deal with packedness like in gnat_to_gnu_field. */
7301 else
7302 union_field_packed
7305 gnu_variant_part
7307 all_rep_and_size
7313 }
7314 }
7316 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses and, if we are
7317 permitted to reorder components, self-referential sizes or variable sizes.
7318 If they do, pull them out and put them onto the appropriate list. We have
7319 to do this in a separate pass since we want to handle the discriminants
7320 but can't play with them until we've used them in debugging data above.
7322 Similarly, pull out the fields with zero size and no rep clause, as they
7323 would otherwise modify the layout and thus very likely run afoul of the
7324 Ada semantics, which are different from those of C here.
7326 ??? If we reorder them, debugging information will be wrong but there is
7327 nothing that can be done about this at the moment. */
7330 #define MOVE_FROM_FIELD_LIST_TO(LIST) \
7331 do { \
7332 if (gnu_last) \
7333 DECL_CHAIN (gnu_last) = gnu_next; \
7334 else \
7335 gnu_field_list = gnu_next; \
7336 \
7337 DECL_CHAIN (gnu_field) = (LIST); \
7338 (LIST) = gnu_field; \
7339 } while (0)
7342 {
7346 {
7349 }
7353 {
7356 }
7359 {
7362 }
7365 {
7375 }
7378 }
7380 #undef MOVE_FROM_FIELD_LIST_TO
7384 /* If permitted, we reorder the fields as follows:
7386 1) all fixed length fields,
7387 2) all fields whose length doesn't depend on discriminants,
7388 3) all fields whose length depends on discriminants,
7389 4) the variant part,
7391 within the record and within each variant recursively. */
7393 gnu_field_list
7396 /* Otherwise, if there is an aliased field placed after a field whose length
7397 depends on discriminants, we put all the fields of the latter sort, last.
7398 We need to do this in case an object of this record type is mutable. */
7402 /* If P_REP_LIST is nonzero, this means that we are asked to move the fields
7403 in our REP list to the previous level because this level needs them in
7404 order to do a correct layout, i.e. avoid having overlapping fields. */
7408 /* Otherwise, sort the fields by bit position and put them into their own
7409 record, before the others, if we also have fields without rep clause. */
7411 {
7416 /* If all the fields have a rep clause, we can do a flat layout. */
7417 layout_with_rep = !gnu_field_list
7419 gnu_rep_type
7423 gnu_field;
7429 /* Put the fields in the list in order of increasing position, which
7430 means we start from the end. */
7433 {
7437 }
7441 else
7442 {
7447 /* If FIRST_FREE_POS is nonzero, we need to ensure that the fields
7448 without rep clause are laid out starting from this position.
7449 Therefore, we force it as a minimal size on the REP part. */
7450 gnu_rep_part
7453 /* Chain the REP part at the beginning of the field list. */
7456 }
7457 }
7459 /* Chain the variant part at the end of the field list. */
7471 /* Chain the fields with zero size at the beginning of the field list. */
7477 }
7478 \f
7479 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
7480 placed into an Esize, Component_Bit_Offset, or Component_Size value
7481 in the GNAT tree. */
7483 static Uint
7485 {
7486 TCode tcode;
7491 /* See if we've already saved the value for this node. */
7493 {
7501 }
7502 else
7505 /* If we do not return inside this switch, TCODE will be set to the
7506 code to use for a Create_Node operand and LEN (set above) will be
7507 the number of recursive calls for us to make. */
7510 {
7515 /* The only case we handle here is a simple discriminant reference. */
7517 {
7520 /* Climb up the chain of successive extensions, if any. */
7527 return
7529 }
7536 /* Now just list the operations we handle. */
7567 /* For negative values in sizetype, build NEGATE_EXPR of the opposite.
7568 Such values appear in expressions with aligning patterns. Note that,
7569 since sizetype is unsigned, we have to jump through some hoops. */
7571 {
7575 {
7578 }
7579 }
7583 /* In regular mode, inline back only if symbolic annotation is requested
7584 in order to avoid memory explosion on big discriminated record types.
7585 But not in ASIS mode, as symbolic annotation is required for DDA. */
7587 {
7591 }
7592 else
7595 /* Fall through... */
7599 }
7601 /* Now get each of the operands that's relevant for this code. If any
7602 cannot be expressed as a repinfo node, say we can't. */
7607 {
7610 else
7614 }
7618 /* Save the result in the cache. */
7620 {
7622 /* We can't assume the hash table data hasn't moved since the initial
7623 look up, so we have to search again. Allocating and inserting an
7624 entry at that point would be an alternative, but then we'd better
7625 discard the entry if we decided not to cache it. */
7631 }
7634 }
7636 /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
7637 and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
7638 size and alignment used by Gigi. Prefer SIZE over TYPE_SIZE if non-null.
7639 BY_REF is true if the object is used by reference. */
7641 void
7643 {
7645 {
7648 else
7650 }
7653 {
7662 }
7667 }
7669 /* Return first element of field list whose TREE_PURPOSE is the same as ELEM.
7670 Return NULL_TREE if there is no such element in the list. */
7672 static tree
7674 {
7676 {
7681 }
7683 }
7685 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding GCC type,
7686 set Component_Bit_Offset and Esize of the components to the position and
7687 size used by Gigi. */
7689 static void
7691 {
7692 Entity_Id gnat_field;
7693 tree gnu_list;
7695 /* We operate by first making a list of all fields and their position (we
7696 can get the size easily) and then update all the sizes in the tree. */
7697 gnu_list
7707 {
7709 gnu_list);
7711 {
7712 tree parent_offset;
7714 /* If we are just annotating types and the type is tagged, the tag
7715 and the parent components are not generated by the front-end so
7716 we need to add the appropriate offset to each component without
7717 representation clause. */
7721 {
7722 /* For a component appearing in the current extension, the
7723 offset is the size of the parent. */
7726 parent_offset
7728 bitsizetype);
7729 else
7733 parent_offset
7736 }
7737 else
7740 Set_Component_Bit_Offset
7742 annotate_value
7746 parent_offset)));
7750 }
7752 {
7753 /* If there is no entry, this is an inherited component whose
7754 position is the same as in the parent type. */
7755 Set_Component_Bit_Offset
7761 }
7762 }
7763 }
7764 \f
7765 /* Scan all fields in GNU_TYPE and return a TREE_LIST where TREE_PURPOSE is
7766 the FIELD_DECL and TREE_VALUE a TREE_VEC containing the byte position, the
7767 value to be placed into DECL_OFFSET_ALIGN and the bit position. The list
7768 of fields is flattened, except for variant parts if DO_NOT_FLATTEN_VARIANT
7769 is set to true. GNU_POS is to be added to the position, GNU_BITPOS to the
7770 bit position, OFFSET_ALIGN is the present offset alignment. GNU_LIST is a
7771 pre-existing list to be chained to the newly created entries. */
7773 static tree
7776 {
7777 tree gnu_field;
7780 gnu_field;
7782 {
7787 unsigned int our_offset_align
7796 /* Recurse on internal fields, flattening the nested fields except for
7797 those in the variant part, if requested. */
7799 {
7803 gnu_list
7807 else
7808 gnu_list
7812 }
7813 }
7816 }
7818 /* Return a list describing the substitutions needed to reflect the
7819 discriminant substitutions from GNAT_TYPE to GNAT_SUBTYPE. They can
7820 be in any order. The values in an element of the list are in the form
7821 of operands to SUBSTITUTE_IN_EXPR. DEFINITION is true if this is for
7822 a definition of GNAT_SUBTYPE. */
7826 {
7828 Entity_Id gnat_discrim;
7829 Node_Id gnat_constr;
7836 /* Ignore access discriminants. */
7838 {
7841 elaborate_expression
7847 }
7850 }
7852 /* Scan all fields in QUAL_UNION_TYPE and return a list describing the
7853 variants of QUAL_UNION_TYPE that are still relevant after applying
7854 the substitutions described in SUBST_LIST. GNU_LIST is a pre-existing
7855 list to be prepended to the newly created entries. */
7860 {
7861 tree gnu_field;
7864 gnu_field;
7866 {
7874 /* If the new qualifier is not unconditionally false, its variant may
7875 still be accessed. */
7877 {
7883 /* Recurse on the variant subpart of the variant, if any. */
7889 /* If the new qualifier is unconditionally true, the subsequent
7890 variants cannot be accessed. */
7893 }
7894 }
7897 }
7898 \f
7899 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
7900 corresponding to GNAT_OBJECT. If the size is valid, return an INTEGER_CST
7901 corresponding to its value. Otherwise, return NULL_TREE. KIND is set to
7902 VAR_DECL if we are specifying the size of an object, TYPE_DECL for the
7903 size of a type, and FIELD_DECL for the size of a field. COMPONENT_P is
7904 true if we are being called to process the Component_Size of GNAT_OBJECT;
7905 this is used only for error messages. ZERO_OK is true if a size of zero
7906 is permitted; if ZERO_OK is false, it means that a size of zero should be
7907 treated as an unspecified size. */
7909 static tree
7912 {
7913 Node_Id gnat_error_node;
7916 /* Return 0 if no size was specified. */
7920 /* Ignore a negative size since that corresponds to our back-annotation. */
7924 /* Find the node to use for error messages. */
7931 else
7934 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
7935 but cannot be represented in bitsizetype. */
7938 {
7941 gnat_object);
7942 else
7944 gnat_object);
7946 }
7948 /* Ignore a zero size if it is not permitted. */
7952 /* The size of objects is always a multiple of a byte. */
7955 {
7959 else
7963 }
7965 /* If this is an integral type or a packed array type, the front-end has
7966 already verified the size, so we need not do it here (which would mean
7967 checking against the bounds). However, if this is an aliased object,
7968 it may not be smaller than the type of the object. */
7973 /* If the object is a record that contains a template, add the size of the
7974 template to the specified size. */
7980 /* If a type needs strict alignment, a component of this type in
7981 a packed record cannot be packed and thus uses the type size. */
7984 else
7987 /* Modify the size of a discriminated type to be the maximum size. */
7991 /* If this is an access type or a fat pointer, the minimum size is that given
7992 by the smallest integral mode that's valid for pointers. */
7994 {
7999 }
8001 /* Issue an error either if the default size of the object isn't a constant
8002 or if the new size is smaller than it. */
8006 {
8008 post_error_ne_tree
8011 else
8012 post_error_ne_tree
8016 }
8019 }
8020 \f
8021 /* Similarly, but both validate and process a value of RM size. This routine
8022 is only called for types. */
8024 static void
8026 {
8027 Node_Id gnat_attr_node;
8030 /* Do nothing if no size was specified. */
8034 /* Ignore a negative size since that corresponds to our back-annotation. */
8038 /* Only issue an error if a Value_Size clause was explicitly given.
8039 Otherwise, we'd be duplicating an error on the Size clause. */
8040 gnat_attr_node
8043 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
8044 but cannot be represented in bitsizetype. */
8047 {
8050 gnat_entity);
8052 }
8054 /* Ignore a zero size unless a Value_Size clause exists, or a size clause
8055 exists, or this is an integer type, in which case the front-end will
8056 have always set it. */
8065 /* If the old size is self-referential, get the maximum size. */
8069 /* Issue an error either if the old size of the object isn't a constant or
8070 if the new size is smaller than it. The front-end has already verified
8071 this for scalar and packed array types. */
8079 && TYPE_PACKED_ARRAY_TYPE_P
8082 {
8084 post_error_ne_tree
8088 }
8090 /* Otherwise, set the RM size proper for integral types... */
8097 /* ...or the Ada size for record and union types. */
8101 }
8102 \f
8103 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
8104 a type or object whose present alignment is ALIGN. If this alignment is
8105 valid, return it. Otherwise, give an error and return ALIGN. */
8107 static unsigned int
8109 {
8112 Node_Id gnat_error_node;
8114 /* Don't worry about checking alignment if alignment was not specified
8115 by the source program and we already posted an error for this entity. */
8119 /* Post the error on the alignment clause if any. Note, for the implicit
8120 base type of an array type, the alignment clause is on the first
8121 subtype. */
8129 gnat_error_node =
8132 else
8135 /* Within GCC, an alignment is an integer, so we must make sure a value is
8136 specified that fits in that range. Also, there is an upper bound to
8137 alignments we can support/allow. */
8145 {
8149 /* If the default alignment of "double" or larger scalar types is
8150 specifically capped and the new alignment is above the cap, do
8151 not post an error and change the alignment only if there is an
8152 alignment clause; this makes it possible to have the associated
8153 GCC type overaligned by default for performance reasons. */
8155 {
8156 Entity_Id gnat_type
8158 is_capped_double
8160 }
8162 {
8163 Entity_Id gnat_type
8165 is_capped_double
8167 }
8168 else
8172 {
8175 }
8176 else
8177 {
8184 }
8185 }
8186 else
8187 {
8191 }
8194 }
8195 \f
8196 /* Verify that TYPE is something we can implement atomically. If not, issue
8197 an error for GNAT_ENTITY. COMPONENT_P is true if we are being called to
8198 process a component type. */
8200 static void
8202 {
8204 Node_Id gnat_node;
8205 machine_mode mode;
8208 tree size;
8210 /* If this is an anonymous base type, nothing to check, the error will be
8211 reported on the source type if need be. */
8220 /* Consider all aligned floating-point types atomic and any aligned types
8221 that are represented by integers no wider than a machine word. */
8228 /* For the moment, also allow anything that has an alignment equal to its
8229 size and which is smaller than a word. */
8240 {
8241 unsigned char pragma_id
8246 {
8249 }
8250 }
8255 else
8258 }
8259 \f
8261 /* Helper for the intrin compatibility checks family. Evaluate whether
8262 two types are definitely incompatible. */
8264 static bool
8266 {
8281 {
8288 /* Assume designated types are ok. We'd need to account for char * and
8289 void * variants to do better, which could rapidly get messy and isn't
8290 clearly worth the effort. */
8295 }
8298 }
8300 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8301 on the Ada/builtin argument lists for the INB binding. */
8303 static bool
8305 {
8311 /* Sequence position of the last argument we checked. */
8315 {
8319 /* If we've exhausted both lists simultaneously, we're done. */
8323 /* If one list is shorter than the other, they fail to match. */
8327 /* If we're done with the Ada args and not with the internal builtin
8328 args, or the other way around, complain. */
8331 {
8334 }
8338 {
8342 }
8344 /* Otherwise, check that types match for the current argument. */
8345 argpos ++;
8347 {
8351 }
8356 }
8359 }
8361 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8362 on the Ada/builtin return values for the INB binding. */
8364 static bool
8366 {
8370 /* Accept function imported as procedure, common and convenient. */
8375 /* If return type is Address (integer type), map it to void *. */
8379 /* Check return types compatibility otherwise. Note that this
8380 handles void/void as well. */
8382 {
8386 }
8389 }
8391 /* Check and return whether the Ada and gcc builtin profiles bound by INB are
8392 compatible. Issue relevant warnings when they are not.
8394 This is intended as a light check to diagnose the most obvious cases, not
8395 as a full fledged type compatibility predicate. It is the programmer's
8396 responsibility to ensure correctness of the Ada declarations in Imports,
8397 especially when binding straight to a compiler internal. */
8399 static bool
8401 {
8402 /* Check compatibility on return values and argument lists, each responsible
8403 for posting warnings as appropriate. Ensure use of the proper sloc for
8404 this purpose. */
8417 }
8418 \f
8419 /* Return a FIELD_DECL node modeled on OLD_FIELD. FIELD_TYPE is its type
8420 and RECORD_TYPE is the type of the parent. If SIZE is nonzero, it is the
8421 specified size for this field. POS_LIST is a position list describing
8422 the layout of OLD_FIELD and SUBST_LIST a substitution list to be applied
8423 to this layout. */
8425 static tree
8429 {
8441 /* If the position is now a constant, we can set it as the position of the
8442 field when we make it. Otherwise, we need to deal with it specially. */
8445 else
8448 new_field
8454 {
8456 /* Finalize the position. */
8465 }
8473 }
8475 /* Create the REP part of RECORD_TYPE with REP_TYPE. If MIN_SIZE is nonzero,
8476 it is the minimal size the REP_PART must have. */
8478 static tree
8480 {
8481 tree field;
8491 }
8493 /* Return the REP part of RECORD_TYPE, if any. Otherwise return NULL. */
8495 static tree
8497 {
8500 /* The REP part is the first field, internal, another record, and its name
8501 starts with an 'R'. */
8509 }
8511 /* Return the variant part of RECORD_TYPE, if any. Otherwise return NULL. */
8513 tree
8515 {
8516 tree field;
8518 /* The variant part is the only internal field that is a qualified union. */
8525 }
8527 /* Return a new variant part modeled on OLD_VARIANT_PART. VARIANT_LIST is
8528 the list of variants to be used and RECORD_TYPE is the type of the parent.
8529 POS_LIST is a position list describing the layout of fields present in
8530 OLD_VARIANT_PART and SUBST_LIST a substitution list to be applied to this
8531 layout. */
8533 static tree
8538 {
8546 /* First create the type of the variant part from that of the old one. */
8552 /* If the position of the variant part is constant, subtract it from the
8553 size of the type of the parent to get the new size. This manual CSE
8554 reduces the code size when not optimizing. */
8556 {
8566 first_bit));
8569 }
8570 else
8573 /* Now finish up the new variants and populate the union type. */
8575 {
8579 /* Skip variants that don't belong to this nesting level. */
8583 /* Retrieve the list of fields already added to the new variant. */
8587 /* If the old variant had a variant subpart, we need to create a new
8588 variant subpart and add it to the field list. */
8592 {
8593 tree new_variant_subpart
8598 }
8600 /* Finish up the new variant and create the field. No need for debug
8601 info thanks to the XVS type. */
8605 Empty);
8607 new_field
8615 }
8617 /* Finish up the union type and create the variant part. No need for debug
8618 info thanks to the XVS type. Note that we don't reverse the field list
8619 because VARIANT_LIST has been traversed in reverse order. */
8623 Empty);
8625 new_variant_part
8631 /* With multiple discriminants it is possible for an inner variant to be
8632 statically selected while outer ones are not; in this case, the list
8633 of fields of the inner variant is not flattened and we end up with a
8634 qualified union with a single member. Drop the useless container. */
8636 {
8645 }
8648 }
8650 /* Copy the size (and alignment and alias set) from OLD_TYPE to NEW_TYPE,
8651 which are both RECORD_TYPE, after applying the substitutions described
8652 in SUBST_LIST. */
8654 static void
8657 {
8681 SET_TYPE_ADA_SIZE
8685 /* Finalize the size. */
8688 }
8690 /* Add a parallel type to GNU_TYPE, the translation of GNAT_ENTITY, which is
8691 the implementation type of a packed array type (Is_Packed_Array_Impl_Type).
8692 The parallel type is the original array type if it has been translated. */
8694 static void
8696 {
8697 Entity_Id gnat_original_array_type
8699 tree gnu_original_array_type;
8710 }
8711 \f
8712 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a
8713 type with all size expressions that contain F in a PLACEHOLDER_EXPR
8714 updated by replacing F with R.
8716 The function doesn't update the layout of the type, i.e. it assumes
8717 that the substitution is purely formal. That's why the replacement
8718 value R must itself contain a PLACEHOLDER_EXPR. */
8720 tree
8722 {
8723 tree nt;
8728 {
8734 /* First the domain types of arrays. */
8737 {
8749 SET_TYPE_INDEX_TYPE
8753 }
8755 /* Then the subtypes. */
8758 {
8770 }
8782 /* These should never show up here. */
8786 {
8803 }
8808 {
8810 tree field;
8812 /* Start out with no fields, make new fields, and chain them
8813 in. If we haven't actually changed the type of any field,
8814 discard everything we've done and return the old type. */
8819 {
8824 {
8827 }
8831 {
8834 }
8836 /* Do the substitution inside the qualifier, if any. */
8838 {
8841 {
8844 }
8845 }
8852 }
8862 }
8866 }
8867 }
8868 \f
8869 /* Return the RM size of GNU_TYPE. This is the actual number of bits
8870 needed to represent the object. */
8872 tree
8874 {
8875 /* For integral types, we store the RM size explicitly. */
8879 /* Return the RM size of the actual data plus the size of the template. */
8882 return
8887 /* For record or union types, we store the size explicitly. */
8893 /* For other types, this is just the size. */
8895 }
8896 \f
8897 /* Return the name to be used for GNAT_ENTITY. If a type, create a
8898 fully-qualified name, possibly with type information encoding.
8899 Otherwise, return the name. */
8901 tree
8903 {
8906 }
8908 /* Return an identifier representing the external name to be used for
8909 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
8910 and the specified suffix. */
8912 tree
8914 {
8922 /* A variable using the Stdcall convention lives in a DLL. We adjust
8923 its name to use the jump table, the _imp__NAME contains the address
8924 for the NAME variable. */
8927 {
8933 }
8936 }
8938 /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
8939 string, return a new IDENTIFIER_NODE that is the concatenation of
8940 the name followed by "___" and the specified suffix. */
8942 tree
8944 {
8951 }
8953 /* Initialize data structures of the decl.c module. */
8955 void
8957 {
8958 /* Initialize the cache of annotated values. */
8960 }
8962 /* Destroy data structures of the decl.c module. */
8964 void
8966 {
8967 /* Destroy the cache of annotated values. */
8970 }