| blob | b6df1ae79ef3bc87af147e4c58ca52dd1e0fa9a6 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2014, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License along with GCC; see the file COPYING3. If not see *
19 * <http://www.gnu.org/licenses/>. *
20 * *
21 * GNAT was originally developed by the GNAT team at New York University. *
22 * Extensive contributions were provided by Ada Core Technologies Inc. *
23 * *
24 ****************************************************************************/
56 /* "stdcall" and "thiscall" conventions should be processed in a specific way
57 on 32-bit x86/Windows only. The macros below are helpers to avoid having
58 to check for a Windows specific attribute throughout this unit. */
60 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
61 #ifdef TARGET_64BIT
62 #define Has_Stdcall_Convention(E) \
63 (!TARGET_64BIT && Convention (E) == Convention_Stdcall)
64 #define Has_Thiscall_Convention(E) \
65 (!TARGET_64BIT && is_cplusplus_method (E))
66 #else
67 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
68 #define Has_Thiscall_Convention(E) (is_cplusplus_method (E))
69 #endif
70 #else
71 #define Has_Stdcall_Convention(E) 0
72 #define Has_Thiscall_Convention(E) 0
73 #endif
77 /* Stack realignment is necessary for functions with foreign conventions when
78 the ABI doesn't mandate as much as what the compiler assumes - that is, up
79 to PREFERRED_STACK_BOUNDARY.
81 Such realignment can be requested with a dedicated function type attribute
82 on the targets that support it. We define FOREIGN_FORCE_REALIGN_STACK to
83 characterize the situations where the attribute should be set. We rely on
84 compiler configuration settings for 'main' to decide. */
86 #ifdef MAIN_STACK_BOUNDARY
87 #define FOREIGN_FORCE_REALIGN_STACK \
88 (MAIN_STACK_BOUNDARY < PREFERRED_STACK_BOUNDARY)
89 #else
90 #define FOREIGN_FORCE_REALIGN_STACK 0
91 #endif
93 struct incomplete
94 {
96 tree old_type;
97 Entity_Id full_type;
98 };
100 /* These variables are used to defer recursively expanding incomplete types
101 while we are processing an array, a record or a subprogram type. */
105 /* This variable is used to delay expanding From_Limited_With types until the
106 end of the spec. */
110 tree discriminant;
111 tree replacement;
116 /* The type of the variant. */
117 tree type;
119 /* The associated field. */
120 tree field;
122 /* The value of the qualifier. */
123 tree qual;
125 /* The type of the variant after transformation. */
126 tree new_type;
130 /* A hash table used to cache the result of annotate_value. */
133 {
136 {
138 }
142 {
144 }
146 static void
148 {
154 else
156 }
157 };
204 /* The relevant constituents of a subprogram binding to a GCC builtin. Used
205 to pass around calls performing profile compatibility checks. */
214 \f
215 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
216 entity, return the equivalent GCC tree for that entity (a ..._DECL node)
217 and associate the ..._DECL node with the input GNAT defining identifier.
219 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
220 initial value (in GCC tree form). This is optional for a variable. For
221 a renamed entity, GNU_EXPR gives the object being renamed.
223 DEFINITION is nonzero if this call is intended for a definition. This is
224 used for separate compilation where it is necessary to know whether an
225 external declaration or a definition must be created if the GCC equivalent
226 was not created previously. The value of 1 is normally used for a nonzero
227 DEFINITION, but a value of 2 is used in special circumstances, defined in
228 the code. */
230 tree
232 {
233 /* Contains the kind of the input GNAT node. */
235 /* True if this is a type. */
237 /* True if debug info is requested for this entity. */
239 /* True if this entity is to be considered as imported. */
240 const bool imported_p
242 /* For a type, contains the equivalent GNAT node to be used in gigi. */
244 /* Temporary used to walk the GNAT tree. */
245 Entity_Id gnat_temp;
246 /* Contains the GCC DECL node which is equivalent to the input GNAT node.
247 This node will be associated with the GNAT node by calling at the end
248 of the `switch' statement. */
250 /* Contains the GCC type to be used for the GCC node. */
252 /* Contains the GCC size tree to be used for the GCC node. */
254 /* Contains the GCC name to be used for the GCC node. */
255 tree gnu_entity_name;
256 /* True if we have already saved gnu_decl as a GNAT association. */
258 /* True if we incremented defer_incomplete_level. */
260 /* True if we incremented force_global. */
262 /* True if we should check to see if elaborated during processing. */
264 /* True if we made GNU_DECL and its type here. */
266 /* Size and alignment of the GCC node, if meaningful. */
268 /* Contains the list of attributes directly attached to the entity. */
271 /* Since a use of an Itype is a definition, process it as such if it
272 is not in a with'ed unit. */
274 && is_type
278 {
279 /* Ensure that we are in a subprogram mentioned in the Scope chain of
280 this entity, our current scope is global, or we encountered a task
281 or entry (where we can't currently accurately check scoping). */
284 {
287 }
292 {
297 gnat_temp
309 && (current_function_decl
311 {
314 }
315 }
317 /* This abort means the Itype has an incorrect scope, i.e. that its
318 scope does not correspond to the subprogram it is declared in. */
320 }
322 /* If we've already processed this entity, return what we got last time.
323 If we are defining the node, we should not have already processed it.
324 In that case, we will abort below when we try to save a new GCC tree
325 for this object. We also need to handle the case of getting a dummy
326 type when a Full_View exists but be careful so as not to trigger its
327 premature elaboration. */
330 {
339 {
340 gnu_decl
344 }
347 }
349 /* If this is a numeric or enumeral type, or an access type, a nonzero Esize
350 must be specified unless it was specified by the programmer. Exceptions
351 are for access-to-protected-subprogram types and all access subtypes, as
352 another GNAT type is used to lay out the GCC type for them. */
363 /* The RM size must be specified for all discrete and fixed-point types. */
367 /* If we get here, it means we have not yet done anything with this entity.
368 If we are not defining it, it must be a type or an entity that is defined
369 elsewhere or externally, otherwise we should have defined it already. */
371 || type_annotate_only
372 || is_type
379 /* Get the name of the entity and set up the line number and filename of
380 the original definition for use in any decl we make. Make sure we do not
381 inherit another source location. */
387 /* For cases when we are not defining (i.e., we are referencing from
388 another compilation unit) public entities, show we are at global level
389 for the purpose of computing scopes. Don't do this for components or
390 discriminants since the relevant test is whether or not the record is
391 being defined. */
399 /* Handle any attributes directly attached to the entity. */
403 /* Do some common processing for types. */
405 {
406 /* Compute the equivalent type to be used in gigi. */
409 /* Machine_Attributes on types are expected to be propagated to
410 subtypes. The corresponding Gigi_Rep_Items are only attached
411 to the first subtype though, so we handle the propagation here. */
418 /* Compute a default value for the size of an elementary type. */
420 {
430 else
435 }
436 }
439 {
441 /* If this is a use of a deferred constant without address clause,
442 get its full definition. */
446 {
447 gnu_decl
451 }
453 /* If we have an external constant that we are not defining, get the
454 expression that is was defined to represent. We may throw it away
455 later if it is not a constant. But do not retrieve the expression
456 if it is an allocator because the designated type might be dummy
457 at this point. */
463 {
467 /* The expression may contain N_Expression_With_Actions nodes and
468 thus object declarations from other units. In this case, even
469 though the expression will eventually be discarded since not a
470 constant, the declarations would be stuck either in the global
471 varpool or in the current scope. Therefore we force the local
472 context and create a fake scope that we'll zap at the end. */
474 {
477 }
487 }
489 /* Ignore deferred constant definitions without address clause since
490 they are processed fully in the front-end. If No_Initialization
491 is set, this is not a deferred constant but a constant whose value
492 is built manually. And constants that are renamings are handled
493 like variables. */
495 && !gnu_expr
499 {
503 }
505 /* Ignore constant definitions already marked with the error node. See
506 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
508 && gnu_expr
511 {
514 }
523 {
524 /* The GNAT record where the component was defined. */
527 /* If the entity is a discriminant of an extended tagged type used to
528 rename a discriminant of the parent type, return the latter. */
531 {
532 gnu_decl
537 }
539 /* If the entity is an inherited component (in the case of extended
540 tagged record types), just return the original entity, which must
541 be a FIELD_DECL. Likewise for discriminants. If the entity is a
542 non-girder discriminant (in the case of derived untagged record
543 types), return the stored discriminant it renames. */
546 {
547 gnu_decl
552 }
554 /* Otherwise, if we are not defining this and we have no GCC type
555 for the containing record, make one for it. Then we should
556 have made our own equivalent. */
558 {
559 /* ??? If this is in a record whose scope is a protected
560 type and we have an Original_Record_Component, use it.
561 This is a workaround for major problems in protected type
562 handling. */
566 {
567 gnu_decl
573 }
579 }
581 else
582 /* Here we have no GCC type and this is a reference rather than a
583 definition. This should never happen. Most likely the cause is
584 reference before declaration in the GNAT tree for gnat_entity. */
586 }
592 /* Simple variables, loop variables, Out parameters and exceptions. */
593 object:
594 {
595 /* Always create a variable for volatile objects and variables seen
596 constant but with a Linker_Section pragma. */
597 bool const_flag
614 tree gnu_object_size;
617 {
621 else
623 }
625 /* Get the type after elaborating the renamed object. */
628 /* If this is a standard exception definition, then use the standard
629 exception type. This is necessary to make sure that imported and
630 exported views of exceptions are properly merged in LTO mode. */
635 /* For a debug renaming declaration, build a debug-only entity. */
637 {
638 /* Force a non-null value to make sure the symbol is retained. */
642 integer_minus_one_node));
649 }
651 /* If this is a loop variable, its type should be the base type.
652 This is because the code for processing a loop determines whether
653 a normal loop end test can be done by comparing the bounds of the
654 loop against those of the base type, which is presumed to be the
655 size used for computation. But this is not correct when the size
656 of the subtype is smaller than the type. */
660 /* Reject non-renamed objects whose type is an unconstrained array or
661 any object whose type is a dummy type or void. */
666 {
669 force_global--;
671 }
673 /* If an alignment is specified, use it if valid. Note that exceptions
674 are objects but don't have an alignment. We must do this before we
675 validate the size, since the alignment can affect the size. */
677 {
683 /* No point in changing the type if there is an address clause
684 as the final type of the object will be a reference type. */
687 else
688 {
691 gnu_type
695 /* If a padding record was made, declare it now since it will
696 never be declared otherwise. This is necessary to ensure
697 that its subtrees are properly marked. */
701 }
702 }
704 /* If we are defining the object, see if it has a Size and validate it
705 if so. If we are not defining the object and a Size clause applies,
706 simply retrieve the value. We don't want to ignore the clause and
707 it is expected to have been validated already. Then get the new
708 type, if any. */
717 {
718 gnu_type
724 }
726 /* If this object has self-referential size, it must be a record with
727 a default discriminant. We are supposed to allocate an object of
728 the maximum size in this case, unless it is a constant with an
729 initializing expression, in which case we can get the size from
730 that. Note that the resulting size may still be a variable, so
731 this may end up with an indirect allocation. */
734 {
736 {
739 {
740 /* If the initializing expression is itself a constant,
741 despite having a nominal type with self-referential
742 size, we can get the size directly from it. */
744 && TYPE_IS_PADDING_P
748 || DECL_READONLY_ONCE_ELAB
751 else
752 gnu_size
754 }
755 else
757 }
758 /* We may have no GNU_EXPR because No_Initialization is
759 set even though there's an Expression. */
764 gnu_size
766 (Etype
768 else
769 {
772 }
774 /* If we are at global level and the size isn't constant, call
775 elaborate_expression_1 to make a variable for it rather than
776 calculating it each time. */
781 }
783 /* If the size is zero byte, make it one byte since some linkers have
784 troubles with zero-sized objects. If the object will have a
785 template, that will make it nonzero so don't bother. Also avoid
786 doing that for an object renaming or an object with an address
787 clause, as we would lose useful information on the view size
788 (e.g. for null array slices) and we are not allocating the object
789 here anyway. */
801 /* If this is an object with no specified size and alignment, and
802 if either it is atomic or we are not optimizing alignment for
803 space and it is composite and not an exception, an Out parameter
804 or a reference to another object, and the size of its type is a
805 constant, set the alignment to the smallest one which is not
806 smaller than the size, with an appropriate cap. */
815 && !imported_p
819 {
822 /* No point in promoting the alignment if this doesn't prevent
823 BLKmode access to the object, in particular block copy, as
824 this will for example disable the NRV optimization for it.
825 No point in jumping through all the hoops needed in order
826 to support BIGGEST_ALIGNMENT if we don't really have to.
827 So we cap to the smallest alignment that corresponds to
828 a known efficient memory access pattern of the target. */
830 {
833 }
834 else
835 {
838 }
845 else
848 /* But make sure not to under-align the object. */
852 /* And honor the minimum valid atomic alignment, if any. */
853 #ifdef MINIMUM_ATOMIC_ALIGNMENT
856 #endif
857 }
859 /* If the object is set to have atomic components, find the component
860 type and validate it.
862 ??? Note that we ignore Has_Volatile_Components on objects; it's
863 not at all clear what to do in that case. */
865 {
874 }
876 /* Now check if the type of the object allows atomic access. Note
877 that we must test the type, even if this object has size and
878 alignment to allow such access, because we will be going inside
879 the padded record to assign to the object. We could fix this by
880 always copying via an intermediate value, but it's not clear it's
881 worth the effort. */
885 /* If this is an aliased object with an unconstrained nominal subtype,
886 make a type that includes the template. */
890 {
891 tree gnu_array
893 gnu_type
895 gnu_type,
898 debug_info_p);
899 }
901 /* ??? If this is an object of CW type initialized to a value, try to
902 ensure that the object is sufficient aligned for this value, but
903 without pessimizing the allocation. This is a kludge necessary
904 because we don't support dynamic alignment. */
911 #ifdef MINIMUM_ATOMIC_ALIGNMENT
912 /* If the size is a constant and no alignment is specified, force
913 the alignment to be the minimum valid atomic alignment. The
914 restriction on constant size avoids problems with variable-size
915 temporaries; if the size is variable, there's no issue with
916 atomic access. Also don't do this for a constant, since it isn't
917 necessary and can interfere with constant replacement. Finally,
918 do not do it for Out parameters since that creates an
919 size inconsistency with In parameters. */
929 #endif
931 /* Make a new type with the desired size and alignment, if needed.
932 But do not take into account alignment promotions to compute the
933 size of the object. */
936 {
942 /* If a padding record was made, declare it now since it will
943 never be declared otherwise. This is necessary to ensure
944 that its subtrees are properly marked. */
948 }
950 /* If this is a renaming, avoid as much as possible to create a new
951 object. However, in several cases, creating it is required.
952 This processing needs to be applied to the raw expression so
953 as to make it more likely to rename the underlying object. */
955 {
958 /* If the renamed object had padding, strip off the reference
959 to the inner object and reset our type. */
962 /* Strip useless conversions around the object. */
964 {
967 }
969 /* Or else, if the renamed object has an unconstrained type with
970 default discriminant, use the padded type. */
973 == gnu_type
977 /* Case 1: If this is a constant renaming stemming from a function
978 call, treat it as a normal object whose initial value is what is
979 being renamed. RM 3.3 says that the result of evaluating a
980 function call is a constant object. Treat constant literals
981 the same way. As a consequence, it can be the inner object of
982 a constant renaming. In this case, the renaming must be fully
983 instantiated, i.e. it cannot be a mere reference to (part of) an
984 existing object. */
986 {
993 }
995 /* Otherwise, see if we can proceed with a stabilized version of
996 the renamed entity or if we need to make a new object. */
998 {
1002 /* Case 2: If the renaming entity need not be materialized and
1003 the renamed expression is something we can stabilize, use
1004 that for the renaming. At the global level, we can only do
1005 this if we know no SAVE_EXPRs need be made, because the
1006 expression we return might be used in arbitrary conditional
1007 branches so we must force the evaluation of the SAVE_EXPRs
1008 immediately and this requires a proper function context.
1009 Note that an external constant is at the global level. */
1015 {
1016 maybe_stable_expr
1020 {
1021 /* ??? No DECL_EXPR is created so we need to mark
1022 the expression manually lest it is shared. */
1031 /* This assertion will fail if the renamed object
1032 isn't aligned enough as to make it possible to
1033 honor the alignment set on the renaming. */
1035 {
1036 unsigned int renamed_align
1041 }
1043 }
1045 /* The stabilization failed. Keep maybe_stable_expr
1046 untouched here to let the pointer case below know
1047 about that failure. */
1048 }
1050 /* Case 3: Make this into a constant pointer to the object we
1051 are to rename and attach the object to the pointer if it is
1052 something we can stabilize.
1054 From the proper scope, attached objects will be referenced
1055 directly instead of indirectly via the pointer to avoid
1056 subtle aliasing problems with non-addressable entities.
1057 They have to be stable because we must not evaluate the
1058 variables in the expression every time the renaming is used.
1059 The pointer is called a "renaming" pointer in this case.
1061 In the rare cases where we cannot stabilize the renamed
1062 object, we just make a "bare" pointer and the renamed
1063 object will always be accessed indirectly through it.
1065 Note that we need to preserve the volatility of the renamed
1066 object through the indirection. */
1068 gnu_type
1074 /* If the previous attempt at stabilizing failed, there is
1075 no point in trying again and we reuse the result without
1076 attaching it to the pointer. In this case it will only
1077 be used as the initializing expression of the pointer and
1078 thus needs no special treatment with regard to multiple
1079 evaluations.
1081 Otherwise, try to stabilize and attach the expression to
1082 the pointer if the stabilization succeeds.
1084 Note that this might introduce SAVE_EXPRs and we don't
1085 check whether we are at the global level or not. This
1086 is fine since we are building a pointer initializer and
1087 neither the pointer nor the initializing expression can
1088 be accessed before the pointer elaboration has taken
1089 place in a correct program.
1091 These SAVE_EXPRs will be evaluated at the right place
1092 by either the evaluation of the initializer for the
1093 non-global case or the elaboration code for the global
1094 case, and will be attached to the elaboration procedure
1095 in the latter case. */
1097 {
1098 maybe_stable_expr
1103 }
1108 else
1109 gnu_expr
1114 }
1115 }
1117 /* Make a volatile version of this object's type if we are to make
1118 the object volatile. We also interpret 13.3(19) conservatively
1119 and disallow any optimizations for such a non-constant object. */
1121 || (!const_flag
1124 || imported_p
1129 /* If we are defining an aliased object whose nominal subtype is
1130 unconstrained, the object is a record that contains both the
1131 template and the object. If there is an initializer, it will
1132 have already been converted to the right type, but we need to
1133 create the template if there is no initializer. */
1135 && !gnu_expr
1138 /* Beware that padding might have been introduced above. */
1141 == RECORD_TYPE
1142 && TYPE_CONTAINS_TEMPLATE_P
1144 {
1145 tree template_field
1153 NULL_TREE);
1156 }
1158 /* Convert the expression to the type of the object except in the
1159 case where the object's type is unconstrained or the object's type
1160 is a padded record whose field is of self-referential size. In
1161 the former case, converting will generate unnecessary evaluations
1162 of the CONSTRUCTOR to compute the size and in the latter case, we
1163 want to only copy the actual data. Also don't convert to a record
1164 type with a variant part from a record type without one, to keep
1165 the object simpler. */
1170 && CONTAINS_PLACEHOLDER_P
1178 /* If this is a pointer that doesn't have an initializing expression,
1179 initialize it to NULL, unless the object is imported. */
1182 && !gnu_expr
1186 /* If we are defining the object and it has an Address clause, we must
1187 either get the address expression from the saved GCC tree for the
1188 object if it has a Freeze node, or elaborate the address expression
1189 here since the front-end has guaranteed that the elaboration has no
1190 effects in this case. */
1192 {
1194 tree gnu_address
1200 /* Ignore the size. It's either meaningless or was handled
1201 above. */
1203 /* Convert the type of the object to a reference type that can
1204 alias everything as per 13.3(19). */
1205 gnu_type
1209 const_flag
1213 /* If this is a deferred constant, the initializer is attached to
1214 the full view. */
1216 gnu_expr
1217 = gnat_to_gnu
1220 /* If we don't have an initializing expression for the underlying
1221 variable, the initializing expression for the pointer is the
1222 specified address. Otherwise, we have to make a COMPOUND_EXPR
1223 to assign both the address and the initial value. */
1226 else
1227 gnu_expr
1229 build_binary_op
1232 gnu_address),
1233 gnu_expr),
1234 gnu_address);
1235 }
1237 /* If it has an address clause and we are not defining it, mark it
1238 as an indirect object. Likewise for Stdcall objects that are
1239 imported. */
1243 {
1244 /* Convert the type of the object to a reference type that can
1245 alias everything as per 13.3(19). */
1246 gnu_type
1250 /* No point in taking the address of an initializing expression
1251 that isn't going to be used. */
1254 /* If it has an address clause whose value is known at compile
1255 time, make the object a CONST_DECL. This will avoid a
1256 useless dereference. */
1258 {
1259 Node_Id gnat_address
1263 {
1266 }
1267 }
1270 }
1272 /* If we are at top level and this object is of variable size,
1273 make the actual type a hidden pointer to the real type and
1274 make the initializer be a memory allocation and initialization.
1275 Likewise for objects we aren't defining (presumed to be
1276 external references from other packages), but there we do
1277 not set up an initialization.
1279 If the object's size overflows, make an allocator too, so that
1280 Storage_Error gets raised. Note that we will never free
1281 such memory, so we presume it never will get allocated. */
1284 || !definition
1286 || (gnu_size
1288 size_binop
1290 bitsize_unit_node)),
1292 || !definition
1294 {
1299 /* In case this was a aliased object whose nominal subtype is
1300 unconstrained, the pointer above will be a thin pointer and
1301 build_allocator will automatically make the template.
1303 If we have a template initializer only (that we made above),
1304 pretend there is none and rely on what build_allocator creates
1305 again anyway. Otherwise (if we have a full initializer), get
1306 the data part and feed that to build_allocator.
1308 If we are elaborating a mutable object, tell build_allocator to
1309 ignore a possibly simpler size from the initializer, if any, as
1310 we must allocate the maximum possible size in this case. */
1312 {
1317 {
1318 gnu_alloc_type
1324 else
1325 gnu_expr
1326 = build_component_ref
1330 }
1335 gnat_entity);
1337 gnu_expr
1341 }
1342 else
1343 {
1346 }
1347 }
1349 /* If this object would go into the stack and has an alignment larger
1350 than the largest stack alignment the back-end can honor, resort to
1351 a variable of "aligning type". */
1354 {
1355 /* Create the new variable. No need for extra room before the
1356 aligned field as this is in automatic storage. */
1357 tree gnu_new_type
1361 tree gnu_new_var
1366 /* Initialize the aligned field if we have an initializer. */
1368 add_stmt_with_node
1370 build_component_ref
1373 gnu_expr),
1374 gnat_entity);
1376 /* And setup this entity as a reference to the aligned field. */
1378 gnu_expr
1379 = build_unary_op
1387 }
1389 /* If this is an aliased object with an unconstrained nominal subtype,
1390 we make its type a thin reference, i.e. the reference counterpart
1391 of a thin pointer, so that it points to the array part. This is
1392 aimed at making it easier for the debugger to decode the object.
1393 Note that we have to do that this late because of the couple of
1394 allocation adjustments that might be made just above. */
1398 {
1399 tree gnu_array
1402 /* In case the object with the template has already been allocated
1403 just above, we have nothing to do here. */
1405 {
1406 tree gnu_unc_var
1412 gnu_expr
1420 }
1422 gnu_type
1424 }
1429 /* Convert the expression to the type of the object except in the
1430 case where the object's type is unconstrained or the object's type
1431 is a padded record whose field is of self-referential size. In
1432 the former case, converting will generate unnecessary evaluations
1433 of the CONSTRUCTOR to compute the size and in the latter case, we
1434 want to only copy the actual data. Also don't convert to a record
1435 type with a variant part from a record type without one, to keep
1436 the object simpler. */
1441 && CONTAINS_PLACEHOLDER_P
1449 /* If this name is external or a name was specified, use it, but don't
1450 use the Interface_Name with an address clause (see cd30005). */
1457 /* If this is an aggregate constant initialized to a constant, force it
1458 to be statically allocated. This saves an initialization copy. */
1460 && const_flag
1469 /* Deal with a pragma Linker_Section on a constant or variable. */
1475 /* Now create the variable or the constant and set various flags. */
1476 gnu_decl
1485 /* If we are defining an Out parameter and optimization isn't enabled,
1486 create a fake PARM_DECL for debugging purposes and make it point to
1487 the VAR_DECL. Suppress debug info for the latter but make sure it
1488 will live in memory so that it can be accessed from within the
1489 debugger through the PARM_DECL. */
1491 && definition
1492 && debug_info_p
1493 && !optimize
1495 {
1502 }
1504 /* If this is a loop parameter, set the corresponding flag. */
1508 /* If this is a renaming pointer, attach the renamed object to it and
1509 register it if we are at the global level. Note that an external
1510 constant is at the global level. */
1512 {
1515 {
1518 }
1519 }
1521 /* If this is a constant and we are defining it or it generates a real
1522 symbol at the object level and we are referencing it, we may want
1523 or need to have a true variable to represent it:
1524 - if optimization isn't enabled, for debugging purposes,
1525 - if the constant is public and not overlaid on something else,
1526 - if its address is taken,
1527 - if either itself or its type is aliased. */
1536 {
1537 tree gnu_corr_var
1541 gnat_entity);
1545 /* As debugging information will be generated for the variable,
1546 do not generate debugging information for the constant. */
1549 else
1551 }
1553 /* If this is a constant, even if we don't need a true variable, we
1554 may need to avoid returning the initializer in every case. That
1555 can happen for the address of a (constant) constructor because,
1556 upon dereferencing it, the constructor will be reinjected in the
1557 tree, which may not be valid in every case; see lvalue_required_p
1558 for more details. */
1562 /* If this object is declared in a block that contains a block with an
1563 exception handler, and we aren't using the GCC exception mechanism,
1564 we must force this variable in memory in order to avoid an invalid
1565 optimization. */
1570 /* If this is a local variable with non-BLKmode and aggregate type,
1571 and optimization isn't enabled, then force it in memory so that
1572 a register won't be allocated to it with possible subparts left
1573 uninitialized and reaching the register allocator. */
1583 /* If we are defining an object with variable size or an object with
1584 fixed size that will be dynamically allocated, and we are using the
1585 setjmp/longjmp exception mechanism, update the setjmp buffer. */
1598 gnat_entity);
1600 /* Back-annotate Esize and Alignment of the object if not already
1601 known. Note that we pick the values of the type, not those of
1602 the object, to shield ourselves from low-level platform-dependent
1603 adjustments like alignment promotion. This is both consistent with
1604 all the treatment above, where alignment and size are set on the
1605 type of the object and not on the object directly, and makes it
1606 possible to support all confirming representation clauses. */
1608 used_by_ref);
1609 }
1613 /* Return a TYPE_DECL for "void" that we previously made. */
1618 /* A special case: for the types Character and Wide_Character in
1619 Standard, we do not list all the literals. So if the literals
1620 are not specified, make this an unsigned integer type. */
1622 {
1626 /* Set TYPE_STRING_FLAG for Character and Wide_Character types.
1627 This is needed by the DWARF-2 back-end to distinguish between
1628 unsigned integer types and character types. */
1630 }
1631 else
1632 {
1633 /* We have a list of enumeral constants in First_Literal. We make a
1634 CONST_DECL for each one and build into GNU_LITERAL_LIST the list
1635 to be placed into TYPE_FIELDS. Each node is itself a TREE_LIST
1636 whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
1637 value of the literal. But when we have a regular boolean type, we
1638 simplify this a little by using a BOOLEAN_TYPE. */
1643 Entity_Id gnat_literal;
1656 {
1657 tree gnu_value
1659 tree gnu_literal
1663 /* Do not generate debug info for individual enumerators. */
1666 gnu_list
1668 }
1673 /* Note that the bounds are updated at the end of this function
1674 to avoid an infinite recursion since they refer to the type. */
1676 }
1682 /* For integer types, just make a signed type the appropriate number
1683 of bits. */
1688 {
1689 /* For modular types, make the unsigned type of the proper number
1690 of bits and then set up the modulus, if required. */
1693 /* Packed Array Impl. Types are supposed to be subtypes only. */
1698 /* Get the modulus in this type. If it overflows, assume it is because
1699 it is equal to 2**Esize. Note that there is no overflow checking
1700 done on unsigned type, so we detect the overflow by looking for
1701 a modulus of zero, which is otherwise invalid. */
1705 {
1710 }
1712 /* If the upper bound is not maximal, make an extra subtype. */
1715 {
1722 }
1723 }
1732 /* For integral subtypes, we make a new INTEGER_TYPE. Note that we do
1733 not want to call create_range_type since we would like each subtype
1734 node to be distinct. ??? Historically this was in preparation for
1735 when memory aliasing is implemented, but that's obsolete now given
1736 the call to relate_alias_sets below.
1738 The TREE_TYPE field of the INTEGER_TYPE points to the base type;
1739 this fact is used by the arithmetic conversion functions.
1741 We elaborate the Ancestor_Subtype if it is not in the current unit
1742 and one of our bounds is non-static. We do this to ensure consistent
1743 naming in the case where several subtypes share the same bounds, by
1744 elaborating the first such subtype first, thus using its name. */
1753 /* Set the precision to the Esize except for bit-packed arrays. */
1758 /* This should be an unsigned type if the base type is unsigned or
1759 if the lower bound is constant and non-negative or if the type
1760 is biased. */
1765 else
1769 SET_TYPE_RM_MIN_VALUE
1775 SET_TYPE_RM_MAX_VALUE
1784 /* Inherit our alias set from what we're a subtype of. Subtypes
1785 are not different types and a pointer can designate any instance
1786 within a subtype hierarchy. */
1789 /* One of the above calls might have caused us to be elaborated,
1790 so don't blow up if so. */
1792 {
1795 }
1797 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
1801 /* For a packed array, make the original array type a parallel type. */
1805 discrete_type:
1807 /* We have to handle clauses that under-align the type specially. */
1810 && Present
1813 {
1817 }
1819 /* If the type we are dealing with represents a bit-packed array,
1820 we need to have the bits left justified on big-endian targets
1821 and right justified on little-endian targets. We also need to
1822 ensure that when the value is read (e.g. for comparison of two
1823 such values), we only get the good bits, since the unused bits
1824 are uninitialized. Both goals are accomplished by wrapping up
1825 the modular type in an enclosing record type. */
1828 {
1831 /* Set the RM size before wrapping up the original type. */
1836 /* Create a stripped-down declaration, mainly for debugging. */
1838 gnat_entity);
1840 /* Now save it and build the enclosing record type. */
1850 /* Propagate the alignment of the modular type to the record type,
1851 unless there is an alignment clause that under-aligns the type.
1852 This means that bit-packed arrays are given "ceil" alignment for
1853 their size by default, which may seem counter-intuitive but makes
1854 it possible to overlay them on modular types easily. */
1860 /* Don't declare the field as addressable since we won't be taking
1861 its address and this would prevent create_field_decl from making
1862 a bitfield. */
1863 gnu_field
1867 /* Do not emit debug info until after the parallel type is added. */
1873 {
1874 /* Make the original array type a parallel type. */
1878 }
1879 }
1881 /* If the type we are dealing with has got a smaller alignment than the
1882 natural one, we need to wrap it up in a record type and misalign the
1883 latter; we reuse the padding machinery for this purpose. Note that,
1884 even if the record type is marked as packed because of misalignment,
1885 we don't pack the field so as to give it the size of the type. */
1887 {
1890 /* Set the RM size before wrapping up the type. */
1894 /* Create a stripped-down declaration, mainly for debugging. */
1896 gnat_entity);
1898 /* Now save it and build the enclosing record type. */
1910 /* Don't declare the field as addressable since we won't be taking
1911 its address and this would prevent create_field_decl from making
1912 a bitfield. */
1913 gnu_field
1921 }
1926 /* The type of the Low and High bounds can be our type if this is
1927 a type from Standard, so set them at the end of the function. */
1934 /* See the E_Signed_Integer_Subtype case for the rationale. */
1951 SET_TYPE_RM_MIN_VALUE
1957 SET_TYPE_RM_MAX_VALUE
1963 /* Inherit our alias set from what we're a subtype of, as for
1964 integer subtypes. */
1967 /* One of the above calls might have caused us to be elaborated,
1968 so don't blow up if so. */
1972 /* Array Types and Subtypes
1974 Unconstrained array types are represented by E_Array_Type and
1975 constrained array types are represented by E_Array_Subtype. There
1976 are no actual objects of an unconstrained array type; all we have
1977 are pointers to that type.
1979 The following fields are defined on array types and subtypes:
1981 Component_Type Component type of the array.
1982 Number_Dimensions Number of dimensions (an int).
1983 First_Index Type of first index. */
1986 {
1987 const bool convention_fortran_p
1990 tree gnu_template_type;
1991 tree gnu_ptr_template;
1998 tree comp_type;
2000 /* Create the type for the component now, as it simplifies breaking
2001 type reference loops. */
2002 comp_type
2005 {
2006 /* As a side effect, the type may have been translated. */
2009 }
2011 /* We complete an existing dummy fat pointer type in place. This both
2012 avoids further complex adjustments in update_pointer_to and yields
2013 better debugging information in DWARF by leveraging the support for
2014 incomplete declarations of "tagged" types in the DWARF back-end. */
2017 {
2020 /* Save the contents of the dummy type for update_pointer_to. */
2022 gnu_ptr_template =
2025 }
2026 else
2027 {
2031 }
2033 /* Make a node for the array. If we are not defining the array
2034 suppress expanding incomplete types. */
2038 {
2039 defer_incomplete_level++;
2041 }
2043 /* Build the fat pointer type. Use a "void *" object instead of
2044 a pointer to the array type since we don't have the array type
2045 yet (it will reference the fat pointer via the bounds). */
2046 tem
2054 {
2055 /* We are going to lay it out again so reset the alias set. */
2061 {
2064 }
2065 }
2066 else
2067 {
2070 }
2072 /* Build a reference to the template from a PLACEHOLDER_EXPR that
2073 is the fat pointer. This will be used to access the individual
2074 fields once we build them. */
2078 gnu_template_reference
2083 /* Now create the GCC type for each index and add the fields for that
2084 index to the template. */
2090 {
2092 tree gnu_index_base_type
2097 /* Make the FIELD_DECLs for the low and high bounds of this
2098 type and then make extractions of these fields from the
2099 template. */
2102 gnu_index_base_type,
2110 gnu_index_base_type,
2118 /* We can't use build_component_ref here since the template type
2119 isn't complete yet. */
2122 NULL_TREE);
2125 NULL_TREE);
2131 /* Compute the size of this dimension. See the E_Array_Subtype
2132 case below for the rationale. */
2133 gnu_high
2137 gnu_max,
2140 /* Make a range type with the new range in the Ada base type.
2141 Then make an index type with the size range in sizetype. */
2145 gnu_orig_min,
2146 gnu_orig_max),
2147 gnat_entity);
2149 /* Update the maximum size of the array in elements. */
2151 {
2153 tree gnu_min
2155 tree gnu_max
2157 tree gnu_this_max
2164 else
2165 gnu_max_size
2167 }
2171 }
2173 /* Install all the fields into the template. */
2178 gnu_template_fields
2181 debug_info_p);
2184 /* If Component_Size is not already specified, annotate it with the
2185 size of the component. */
2190 /* Compute the maximum size of the array in units and bits. */
2192 {
2198 }
2199 else
2202 /* Now build the array type. */
2205 {
2213 /* If it is passed by reference, force BLKmode to ensure that
2214 objects of this type will always be put in memory. */
2218 }
2222 /* If an alignment is specified, use it if valid. But ignore it
2223 for the original type of packed array types. If the alignment
2224 was requested with an explicit alignment clause, state so. */
2227 {
2233 }
2237 /* Adjust the type of the pointer-to-array field of the fat pointer
2238 and record the aliasing relationships if necessary. */
2243 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2244 corresponding fat pointer. */
2251 /* If the maximum size doesn't overflow, use it. */
2257 {
2262 }
2266 gnat_entity);
2268 /* Give the fat pointer type a name. If this is a packed array, tell
2269 the debugger how to interpret the underlying bits. */
2272 else
2276 gnat_entity);
2278 /* Create the type to be designated by thin pointers: a record type for
2279 the array and its template. We used to shift the fields to have the
2280 template at a negative offset, but this was somewhat of a kludge; we
2281 now shift thin pointer values explicitly but only those which have a
2282 TYPE_UNCONSTRAINED_ARRAY attached to the designated RECORD_TYPE. */
2285 debug_info_p);
2289 }
2294 /* This is the actual data type for array variables. Multidimensional
2295 arrays are implemented as arrays of arrays. Note that arrays which
2296 have sparse enumeration subtypes as index components create sparse
2297 arrays, which is obviously space inefficient but so much easier to
2298 code for now.
2300 Also note that the subtype never refers to the unconstrained array
2301 type, which is somewhat at variance with Ada semantics.
2303 First check to see if this is simply a renaming of the array type.
2304 If so, the result is the array type. */
2308 ;
2309 else
2310 {
2312 const bool convention_fortran_p
2321 /* First create the GCC type for each index and find out whether
2322 special types are needed for debugging information. */
2325 gnat_base_index
2331 {
2334 tree gnu_orig_min
2337 tree gnu_orig_max
2342 tree gnu_base_index_type
2344 tree gnu_base_index_base_type
2346 tree gnu_base_orig_min
2349 tree gnu_base_orig_max
2352 tree gnu_high;
2354 /* See if the base array type is already flat. If it is, we
2355 are probably compiling an ACATS test but it will cause the
2356 code below to malfunction if we don't handle it specially. */
2360 {
2364 }
2366 /* Similarly, if one of the values overflows in sizetype and the
2367 range is null, use 1..0 for the sizetype bounds. */
2372 {
2376 }
2378 /* If the minimum and maximum values both overflow in sizetype,
2379 but the difference in the original type does not overflow in
2380 sizetype, ignore the overflow indication. */
2384 && !TREE_OVERFLOW
2387 gnu_orig_max,
2388 gnu_orig_min))))
2389 {
2393 }
2395 /* Compute the size of this dimension in the general case. We
2396 need to provide GCC with an upper bound to use but have to
2397 deal with the "superflat" case. There are three ways to do
2398 this. If we can prove that the array can never be superflat,
2399 we can just use the high bound of the index type. */
2402 /* Bit-Packed Array Impl. Types are never superflat. */
2404 && Is_Bit_Packed_Array
2408 /* Otherwise, if the high bound is constant but the low bound is
2409 not, we use the expression (hb >= lb) ? lb : hb + 1 for the
2410 lower bound. Note that the comparison must be done in the
2411 original type to avoid any overflow during the conversion. */
2414 {
2416 gnu_min
2419 boolean_type_node,
2420 gnu_orig_max,
2421 gnu_orig_min),
2422 gnu_min,
2424 size_one_node));
2425 }
2427 /* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
2428 in all the other cases. Note that, here as well as above,
2429 the condition used in the comparison must be equivalent to
2430 the condition (length != 0). This is relied upon in order
2431 to optimize array comparisons in compare_arrays. Moreover
2432 we use int_const_binop for the shift by 1 if the bound is
2433 constant to avoid any unwanted overflow. */
2434 else
2435 gnu_high
2438 boolean_type_node,
2439 gnu_orig_max,
2440 gnu_orig_min),
2441 gnu_max,
2444 size_one_node)
2446 size_one_node));
2448 /* Reuse the index type for the range type. Then make an index
2449 type with the size range in sizetype. */
2452 gnat_entity);
2454 /* Update the maximum size of the array in elements. Here we
2455 see if any constraint on the index type of the base type
2456 can be used in the case of self-referential bound on the
2457 index type of the subtype. We look for a non-"infinite"
2458 and non-self-referential bound from any type involved and
2459 handle each bound separately. */
2461 {
2464 tree gnu_base_index_base_type
2466 tree gnu_base_base_min
2469 tree gnu_base_base_max
2490 else
2491 {
2492 tree gnu_this_max;
2494 /* Use int_const_binop if the bounds are constant to
2495 avoid any unwanted overflow. */
2498 gnu_this_max
2501 gnu_base_max,
2502 gnu_base_min));
2503 else
2504 gnu_this_max
2507 gnu_base_max,
2508 gnu_base_min));
2510 gnu_max_size
2512 }
2513 }
2515 /* We need special types for debugging information to point to
2516 the index types if they have variable bounds, are not integer
2517 types or are biased. */
2526 }
2528 /* Then flatten: create the array of arrays. For an array type
2529 used to implement a packed array, get the component type from
2530 the original array type since the representation clauses that
2531 can affect it are on the latter. */
2534 {
2539 /* One of the above calls might have caused us to be elaborated,
2540 so don't blow up if so. */
2542 {
2545 }
2546 }
2547 else
2548 {
2550 debug_info_p);
2552 /* One of the above calls might have caused us to be elaborated,
2553 so don't blow up if so. */
2555 {
2558 }
2559 }
2561 /* Compute the maximum size of the array in units and bits. */
2563 {
2569 }
2570 else
2573 /* Now build the array type. */
2575 {
2582 /* See the E_Array_Type case for the rationale. */
2586 }
2590 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
2594 /* If we are at file level and this is a multi-dimensional array,
2595 we need to make a variable corresponding to the stride of the
2596 inner dimensions. */
2598 {
2600 tree gnu_arr_type;
2606 {
2614 /* ??? For now, store the size as a multiple of the
2615 alignment of the element type in bytes so that we
2616 can see the alignment from the tree. */
2619 gnat_entity,
2624 /* ??? create_type_decl is not invoked on the inner types so
2625 the MULT_EXPR node built above will never be marked. */
2627 }
2628 }
2630 /* If we need to write out a record type giving the names of the
2631 bounds for debugging purposes, do it now and make the record
2632 type a parallel type. This is not needed for a packed array
2633 since the bounds are conveyed by the original array type. */
2635 && debug_info_p
2637 {
2640 tree gnu_field;
2646 {
2650 /* Make sure to reference the types themselves, and not just
2651 their names, as the debugger may fall back on them. */
2657 }
2661 }
2663 /* If this is a packed array type, make the original array type a
2664 parallel type. Otherwise, do it for the base array type if it
2665 isn't artificial to make sure it is kept in the debug info. */
2667 {
2670 else
2671 {
2672 tree gnu_base_decl
2677 }
2678 }
2685 /* If the size is self-referential and the maximum size doesn't
2686 overflow, use it. */
2688 && gnu_max_size
2693 {
2699 }
2701 /* Set our alias set to that of our base type. This gives all
2702 array subtypes the same alias set. */
2705 /* If this is a packed type, make this type the same as the packed
2706 array type, but do some adjusting in the type first. */
2708 {
2709 Entity_Id gnat_index;
2710 tree gnu_inner;
2712 /* First finish the type we had been making so that we output
2713 debugging information for it. */
2716 gnu_type
2718 /* Make it artificial only if the base type was artificial too.
2719 That's sort of "morally" true and will make it possible for
2720 the debugger to look it up by name in DWARF, which is needed
2721 in order to decode the packed array type. */
2722 gnu_decl
2728 /* Save it as our equivalent in case the call below elaborates
2729 this type again. */
2732 gnu_decl
2745 /* We need to attach the index type to the type we just made so
2746 that the actual bounds can later be put into a template. */
2751 {
2753 {
2754 /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
2755 TYPE_MODULUS for modular types so we make an extra
2756 subtype if necessary. */
2758 {
2759 tree gnu_subtype
2768 }
2772 #ifdef ENABLE_CHECKING
2773 /* Check for other cases of overloading. */
2775 #endif
2776 }
2781 SET_TYPE_ACTUAL_BOUNDS
2788 SET_TYPE_ACTUAL_BOUNDS
2794 }
2795 }
2797 else
2798 /* Abort if packed array with no Packed_Array_Impl_Type. */
2800 }
2804 /* Create the type for a string literal. */
2805 {
2806 Entity_Id gnat_full_type
2811 tree gnu_string_array_type
2813 tree gnu_string_index_type
2816 tree gnu_lower_bound
2819 tree gnu_length
2821 gnu_string_index_type);
2822 tree gnu_upper_bound
2824 gnu_lower_bound,
2827 integer_one_node)));
2828 tree gnu_index_type
2832 gnu_lower_bound,
2833 gnu_upper_bound),
2834 gnat_entity);
2836 gnu_type
2839 gnu_index_type);
2843 }
2846 /* Record Types and Subtypes
2848 The following fields are defined on record types:
2850 Has_Discriminants True if the record has discriminants
2851 First_Discriminant Points to head of list of discriminants
2852 First_Entity Points to head of list of fields
2853 Is_Tagged_Type True if the record is tagged
2855 Implementation of Ada records and discriminated records:
2857 A record type definition is transformed into the equivalent of a C
2858 struct definition. The fields that are the discriminants which are
2859 found in the Full_Type_Declaration node and the elements of the
2860 Component_List found in the Record_Type_Definition node. The
2861 Component_List can be a recursive structure since each Variant of
2862 the Variant_Part of the Component_List has a Component_List.
2864 Processing of a record type definition comprises starting the list of
2865 field declarations here from the discriminants and the calling the
2866 function components_to_record to add the rest of the fields from the
2867 component list and return the gnu type node. The function
2868 components_to_record will call itself recursively as it traverses
2869 the tree. */
2873 {
2874 gnu_type
2875 = build_complex_type
2876 (get_unpadded_type
2879 (Component_List
2880 (Type_Definition
2884 }
2886 {
2889 Node_Id gnat_constr;
2890 Entity_Id gnat_field;
2892 tree gnu_get_parent;
2893 /* Set PACKED in keeping with gnat_to_gnu_field. */
2894 const int packed
2906 const bool is_extension
2912 /* See if all fields have a rep clause. Stop when we find one
2913 that doesn't. */
2921 {
2924 }
2926 /* If this is a record extension, go a level further to find the
2927 record definition. Also, verify we have a Parent_Subtype. */
2929 {
2936 }
2938 /* Make a node for the record. If we are not defining the record,
2939 suppress expanding incomplete types. */
2948 {
2949 defer_incomplete_level++;
2951 }
2953 /* If both a size and rep clause was specified, put the size in
2954 the record type now so that it can get the proper mode. */
2959 /* Always set the alignment here so that it can be used to
2960 set the mode, if it is making the alignment stricter. If
2961 it is invalid, it will be checked again below. If this is to
2962 be Atomic, choose a default alignment of a word unless we know
2963 the size and it's smaller. */
2968 {
2972 }
2973 /* If a type needs strict alignment, the minimum size will be the
2974 type size instead of the RM size (see validate_size). Cap the
2975 alignment, lest it causes this type size to become too large. */
2977 {
2982 }
2983 else
2986 /* If we have a Parent_Subtype, make a field for the parent. If
2987 this record has rep clauses, force the position to zero. */
2989 {
2992 tree gnu_parent;
2994 /* A major complexity here is that the parent subtype will
2995 reference our discriminants in its Stored_Constraint list.
2996 But those must reference the parent component of this record
2997 which is precisely of the parent subtype we have not built yet!
2998 To break the circle we first build a dummy COMPONENT_REF which
2999 represents the "get to the parent" operation and initialize
3000 each of those discriminants to a COMPONENT_REF of the above
3001 dummy parent referencing the corresponding discriminant of the
3002 base type of the parent subtype. */
3007 gnu_dummy_parent_type),
3008 NULL_TREE);
3015 {
3016 tree gnu_field
3019 save_gnu_tree
3024 }
3026 /* Then we build the parent subtype. If it has discriminants but
3027 the type itself has unknown discriminants, this means that it
3028 doesn't contain information about how the discriminants are
3029 derived from those of the ancestor type, so it cannot be used
3030 directly. Instead it is built by cloning the parent subtype
3031 of the underlying record view of the type, for which the above
3032 derivation of discriminants has been made explicit. */
3035 {
3038 /* If we are defining the type, the underlying record
3039 view must already have been elaborated at this point.
3040 Otherwise do it now as its parent subtype cannot be
3041 technically elaborated on its own. */
3044 else
3049 /* Substitute the "get to the parent" of the type for that
3050 of its underlying record view in the cloned type. */
3055 {
3057 tree gnu_ref
3060 gnu_parent
3062 }
3063 }
3064 else
3067 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
3068 initially built. The discriminants must reference the fields
3069 of the parent subtype and not those of its base type for the
3070 placeholder machinery to properly work. */
3072 {
3073 /* The actual parent subtype is the full view. */
3075 {
3078 else
3080 }
3086 {
3087 Entity_Id field;
3096 }
3097 }
3099 /* The "get to the parent" COMPONENT_REF must be given its
3100 proper type... */
3103 /* ...and reference the _Parent field of this record. */
3104 gnu_field
3107 has_rep
3109 has_rep
3115 }
3117 /* Make the fields for the discriminants and put them into the record
3118 unless it's an Unchecked_Union. */
3123 {
3124 /* If this is a record extension and this discriminant is the
3125 renaming of another discriminant, we've handled it above. */
3130 gnu_field
3132 debug_info_p);
3134 /* Make an expression using a PLACEHOLDER_EXPR from the
3135 FIELD_DECL node just created and link that with the
3136 corresponding GNAT defining identifier. */
3144 {
3147 }
3148 }
3150 /* If we have a derived untagged type that renames discriminants in
3151 the root type, the (stored) discriminants are a just copy of the
3152 discriminants of the root type. This means that any constraints
3153 added by the renaming in the derivation are disregarded as far
3154 as the layout of the derived type is concerned. To rescue them,
3155 we change the type of the (stored) discriminants to a subtype
3156 with the bounds of the type of the visible discriminants. */
3158 && !is_extension
3164 /* Ignore access discriminants. */
3167 {
3171 /* If the scope of the discriminant is not the record type,
3172 this means that we're processing the implicit full view
3173 of a type derived from a private discriminated type: in
3174 this case, the Stored_Constraint list is simply copied
3175 from the partial view, see Build_Derived_Private_Type.
3176 So we need to retrieve the corresponding discriminant
3177 of the implicit full view, otherwise we will abort. */
3179 {
3180 Entity_Id field;
3189 }
3192 gnu_ref
3196 /* GNU_REF must be an expression using a PLACEHOLDER_EXPR built
3197 just above for one of the stored discriminants. */
3201 {
3203 tree gnu_subtype
3214 }
3215 }
3217 /* Add the fields into the record type and finish it up. */
3225 /* If it is passed by reference, force BLKmode to ensure that objects
3226 of this type will always be put in memory. */
3233 /* Fill in locations of fields. */
3236 /* If there are any entities in the chain corresponding to components
3237 that we did not elaborate, ensure we elaborate their types if they
3238 are Itypes. */
3248 /* If this is a record type associated with an exception definition,
3249 equate its fields to those of the standard exception type. This
3250 will make it possible to convert between them. */
3252 {
3253 tree gnu_std_field;
3256 gnu_field;
3261 }
3262 }
3266 /* If an equivalent type is present, that is what we should use.
3267 Otherwise, fall through to handle this like a record subtype
3268 since it may have constraints. */
3270 {
3274 }
3276 /* ... fall through ... */
3279 /* If Cloned_Subtype is Present it means this record subtype has
3280 identical layout to that type or subtype and we should use
3281 that GCC type for this one. The front end guarantees that
3282 the component list is shared. */
3284 {
3289 }
3291 /* Otherwise, first ensure the base type is elaborated. Then, if we are
3292 changing the type, make a new type with each field having the type of
3293 the field in the new subtype but the position computed by transforming
3294 every discriminant reference according to the constraints. We don't
3295 see any difference between private and non-private type here since
3296 derivations from types should have been deferred until the completion
3297 of the private type. */
3298 else
3299 {
3301 tree gnu_base_type;
3304 {
3305 defer_incomplete_level++;
3307 }
3312 {
3315 }
3317 /* If this is a record subtype associated with a dispatch table,
3318 strip the suffix. This is necessary to make sure 2 different
3319 subtypes associated with the imported and exported views of a
3320 dispatch table are properly merged in LTO mode. */
3322 {
3329 }
3331 /* When the subtype has discriminants and these discriminants affect
3332 the initial shape it has inherited, factor them in. But for an
3333 Unchecked_Union (it must be an Itype), just return the type.
3334 We can't just test Is_Constrained because private subtypes without
3335 discriminants of types with discriminants with default expressions
3336 are Is_Constrained but aren't constrained! */
3343 {
3349 Entity_Id gnat_field;
3357 /* Set the size, alignment and alias set of the new type to
3358 match that of the old one, doing required substitutions. */
3360 gnu_subst_list);
3364 else
3367 /* Look for REP and variant parts in the base type. */
3371 /* If there is a variant part, we must compute whether the
3372 constraints statically select a particular variant. If
3373 so, we simply drop the qualified union and flatten the
3374 list of fields. Otherwise we'll build a new qualified
3375 union for the variants that are still relevant. */
3377 {
3381 gnu_variant_list
3383 gnu_subst_list,
3384 vNULL);
3386 /* If all the qualifiers are unconditionally true, the
3387 innermost variant is statically selected. */
3391 {
3394 }
3396 /* Otherwise, create the new variants. */
3399 {
3402 tree suffix
3404 IDENTIFIER_POINTER
3410 gnu_subst_list);
3412 }
3413 }
3414 else
3415 {
3418 }
3420 /* Make a list of fields and their position in the base type. */
3421 gnu_pos_list
3428 /* Now go down every component in the subtype and compute its
3429 size and position from those of the component in the base
3430 type and from the constraints of the subtype. */
3438 && Underlying_Type
3441 {
3443 Entity_Id gnat_old_field
3445 tree gnu_old_field
3451 /* If the type is the same, retrieve the GCC type from the
3452 old field to take into account possible adjustments. */
3455 else
3458 /* If there was a component clause, the field types must be
3459 the same for the type and subtype, so copy the data from
3460 the old field to avoid recomputation here. Also if the
3461 field is justified modular and the optimization in
3462 gnat_to_gnu_field was applied. */
3468 {
3471 }
3473 /* If the old field was packed and of constant size, we
3474 have to get the old size here, as it might differ from
3475 what the Etype conveys and the latter might overlap
3476 onto the following field. Try to arrange the type for
3477 possible better packing along the way. */
3481 {
3486 gnu_field_type
3488 }
3490 else
3493 /* If the context of the old field is the base type or its
3494 REP part (if any), put the field directly in the new
3495 type; otherwise look up the context in the variant list
3496 and put the field either in the new type if there is a
3497 selected variant or in one of the new variants. */
3499 || (gnu_rep_part
3502 else
3503 {
3506 tree rep_part;
3514 {
3517 else
3519 }
3520 else
3521 /* The front-end may pass us "ghost" components if
3522 it fails to recognize that a constrained subtype
3523 is statically constrained. Discard them. */
3525 }
3527 /* Now create the new field modeled on the old one. */
3528 gnu_field
3534 /* Put it in one of the new variants directly. */
3536 {
3539 }
3541 /* To match the layout crafted in components_to_record,
3542 if this is the _Tag or _Parent field, put it before
3543 any other fields. */
3548 /* Similarly, if this is the _Controller field, put
3549 it before the other fields except for the _Tag or
3550 _Parent field. */
3552 {
3555 }
3557 /* Otherwise, if this is a regular field, put it after
3558 the other fields. */
3559 else
3560 {
3567 }
3570 }
3572 /* If there is a variant list, a selected variant and the fields
3573 all have a constant position, put them in order of increasing
3574 position to match that of constant CONSTRUCTORs. Likewise if
3575 there is no variant list but a REP part, since the latter has
3576 been flattened in the process. */
3580 {
3592 {
3595 }
3596 }
3598 /* If there is a variant list and no selected variant, we need
3599 to create the nest of variant parts from the old nest. */
3601 {
3602 tree new_variant_part
3608 }
3610 /* Now go through the entities again looking for Itypes that
3611 we have not elaborated but should (e.g., Etypes of fields
3612 that have Original_Components). */
3620 /* Do not emit debug info for the type yet since we're going to
3621 modify it below. */
3626 /* See the E_Record_Type case for the rationale. */
3633 /* Fill in locations of fields. */
3636 /* If debugging information is being written for the type, write
3637 a record that shows what we are a subtype of and also make a
3638 variable that indicates our size, if still variable. */
3640 {
3642 tree gnu_unpad_base_name
3650 build_reference_type
3652 gnu_subtype_marker,
3667 gnat_entity);
3668 }
3673 /* Now we can finalize it. */
3675 }
3677 /* Otherwise, go down all the components in the new type and make
3678 them equivalent to those in the base type. */
3679 else
3680 {
3690 gnat_to_gnu_field_decl
3693 }
3694 }
3698 /* Use the special descriptor type for dispatch tables if needed,
3699 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3700 Note that we are only required to do so for static tables in
3701 order to be compatible with the C++ ABI, but Ada 2005 allows
3702 to extend library level tagged types at the local level so
3703 we do it in the non-static case as well. */
3706 {
3710 }
3712 /* ... fall through ... */
3715 /* If we are not defining this entity, and we have incomplete
3716 entities being processed above us, make a dummy type and
3717 fill it in later. */
3719 {
3722 gnu_type
3723 = build_pointer_type
3738 }
3740 /* ... fall through ... */
3747 {
3748 /* The designated type and its equivalent type for gigi. */
3751 /* Whether it comes from a limited with. */
3752 bool is_from_limited_with
3755 /* The "full view" of the designated type. If this is an incomplete
3756 entity from a limited with, treat its non-limited view as the full
3757 view. Otherwise, if this is an incomplete or private type, use the
3758 full view. In the former case, we might point to a private type,
3759 in which case, we need its full view. Also, we want to look at the
3760 actual type used for the representation, so this takes a total of
3761 three steps. */
3762 Entity_Id gnat_desig_full_direct_first
3763 = (is_from_limited_with
3767 Entity_Id gnat_desig_full_direct
3768 = ((is_from_limited_with
3773 Entity_Id gnat_desig_full
3775 /* The type actually used to represent the designated type, either
3776 gnat_desig_full or gnat_desig_equiv. */
3777 Entity_Id gnat_desig_rep;
3778 /* True if this is a pointer to an unconstrained array. */
3780 /* We want to know if we'll be seeing the freeze node for any
3781 incomplete type we may be pointing to. */
3782 bool in_main_unit
3786 /* True if we make a dummy type here. */
3788 /* The mode to be used for the pointer type. */
3790 /* The GCC type used for the designated type. */
3796 /* If either the designated type or its full view is an unconstrained
3797 array subtype, replace it with the type it's a subtype of. This
3798 avoids problems with multiple copies of unconstrained array types.
3799 Likewise, if the designated type is a subtype of an incomplete
3800 record type, use the parent type to avoid order of elaboration
3801 issues. This can lose some code efficiency, but there is no
3802 alternative. */
3813 /* Set the type that's actually the representation of the designated
3814 type and also flag whether we have a unconstrained array. */
3815 gnat_desig_rep
3817 is_unconstrained_array
3820 /* If we are pointing to an incomplete type whose completion is an
3821 unconstrained array, make dummy fat and thin pointer types to it.
3822 Likewise if the type itself is dummy or an unconstrained array. */
3826 && TYPE_IS_DUMMY_P
3828 || (!in_main_unit
3831 || (in_main_unit
3832 && is_from_limited_with
3834 {
3837 else
3838 {
3841 }
3843 /* If the call above got something that has a pointer, the pointer
3844 is our type. This could have happened either because the type
3845 was elaborated or because somebody else executed the code. */
3849 }
3851 /* If we already know what the full type is, use it. */
3856 /* Get the type of the thing we are to point to and build a pointer to
3857 it. If it is a reference to an incomplete or private type with a
3858 full view that is a record, make a dummy type node and get the
3859 actual type later when we have verified it is safe. */
3865 /* Likewise if we are pointing to a record or array and we are
3866 to defer elaborating incomplete types. We do this as this
3867 access type may be the full view of a private type. Note
3868 that the unconstrained array case is handled above. */
3874 /* If this is a reference from a limited_with type back to our
3875 main unit and there's a freeze node for it, either we have
3876 already processed the declaration and made the dummy type,
3877 in which case we just reuse the latter, or we have not yet,
3878 in which case we make the dummy type and it will be reused
3879 when the declaration is finally processed. In both cases,
3880 the pointer eventually created below will be automatically
3881 adjusted when the freeze node is processed. Note that the
3882 unconstrained array case is handled above. */
3883 || (in_main_unit
3884 && is_from_limited_with
3886 {
3889 }
3891 /* Otherwise handle the case of a pointer to itself. */
3893 {
3894 gnu_type
3898 }
3900 /* If expansion is disabled, the equivalent type of a concurrent type
3901 is absent, so build a dummy pointer type. */
3905 /* Finally, handle the default case where we can just elaborate our
3906 designated type. */
3907 else
3910 /* It is possible that a call to gnat_to_gnu_type above resolved our
3911 type. If so, just return it. */
3913 {
3916 }
3918 /* If we haven't done it yet, build the pointer type the usual way. */
3920 {
3921 /* Modify the designated type if we are pointing only to constant
3922 objects, but don't do it for unconstrained arrays. */
3925 {
3926 gnu_desig_type
3929 /* Some extra processing is required if we are building a
3930 pointer to an incomplete type (in the GCC sense). We might
3931 have such a type if we just made a dummy, or directly out
3932 of the call to gnat_to_gnu_type above if we are processing
3933 an access type for a record component designating the
3934 record type itself. */
3936 {
3937 /* We must ensure that the pointer to variant we make will
3938 be processed by update_pointer_to when the initial type
3939 is completed. Pretend we made a dummy and let further
3940 processing act as usual. */
3943 /* We must ensure that update_pointer_to will not retrieve
3944 the dummy variant when building a properly qualified
3945 version of the complete type. We take advantage of the
3946 fact that get_qualified_type is requiring TYPE_NAMEs to
3947 match to influence build_qualified_type and then also
3948 update_pointer_to here. */
3951 }
3952 }
3954 gnu_type
3957 }
3959 /* If we are not defining this object and we have made a dummy pointer,
3960 save our current definition, evaluate the actual type, and replace
3961 the tentative type we made with the actual one. If we are to defer
3962 actually looking up the actual type, make an entry in the deferred
3963 list. If this is from a limited with, we may have to defer to the
3964 end of the current unit. */
3966 {
3967 tree gnu_old_desig_type;
3970 {
3973 gnu_type = build_pointer_type
3975 }
3976 else
3988 /* Note that the call to gnat_to_gnu_type on gnat_desig_equiv might
3989 update gnu_old_desig_type directly, in which case it will not be
3990 a dummy type any more when we get into update_pointer_to.
3992 This can happen e.g. when the designated type is a record type,
3993 because their elaboration starts with an initial node from
3994 make_dummy_type, which may be the same node as the one we got.
3996 Besides, variants of this non-dummy type might have been created
3997 along the way. update_pointer_to is expected to properly take
3998 care of those situations. */
4000 {
4003 }
4004 else
4005 {
4008 = (is_from_limited_with
4014 }
4015 }
4016 }
4023 else
4024 {
4025 /* The run-time representation is the equivalent type. */
4028 }
4041 /* We treat this as identical to its base type; any constraint is
4042 meaningful only to the front-end.
4044 The designated type must be elaborated as well, if it does
4045 not have its own freeze node. Designated (sub)types created
4046 for constrained components of records with discriminants are
4047 not frozen by the front-end and thus not elaborated by gigi,
4048 because their use may appear before the base type is frozen,
4049 and because it is not clear that they are needed anywhere in
4050 gigi. With the current model, there is no correct place where
4051 they could be elaborated. */
4058 {
4059 /* If we are not defining this entity, and we have incomplete
4060 entities being processed above us, make a dummy type and
4061 elaborate it later. */
4063 {
4066 p->old_type
4071 }
4074 Incomplete_Or_Private_Kind))
4077 }
4082 /* Subprogram Entities
4084 The following access functions are defined for subprograms:
4086 Etype Return type or Standard_Void_Type.
4087 First_Formal The first formal parameter.
4088 Is_Imported Indicates that the subprogram has appeared in
4089 an INTERFACE or IMPORT pragma. For now we
4090 assume that the external language is C.
4091 Is_Exported Likewise but for an EXPORT pragma.
4092 Is_Inlined True if the subprogram is to be inlined.
4094 Each parameter is first checked by calling must_pass_by_ref on its
4095 type to determine if it is passed by reference. For parameters which
4096 are copied in, if they are Ada In Out or Out parameters, their return
4097 value becomes part of a record which becomes the return type of the
4098 function (C function - note that this applies only to Ada procedures
4099 so there is no Ada return type). Additional code to store back the
4100 parameters will be generated on the caller side. This transformation
4101 is done here, not in the front-end.
4103 The intended result of the transformation can be seen from the
4104 equivalent source rewritings that follow:
4106 struct temp {int a,b};
4107 procedure P (A,B: In Out ...) is temp P (int A,B)
4108 begin {
4109 .. ..
4110 end P; return {A,B};
4111 }
4113 temp t;
4114 P(X,Y); t = P(X,Y);
4115 X = t.a , Y = t.b;
4117 For subprogram types we need to perform mainly the same conversions to
4118 GCC form that are needed for procedures and function declarations. The
4119 only difference is that at the end, we make a type declaration instead
4120 of a function declaration. */
4125 {
4126 /* The type returned by a function or else Standard_Void_Type for a
4127 procedure. */
4129 tree gnu_return_type;
4130 /* The first GCC parameter declaration (a PARM_DECL node). The
4131 PARM_DECL nodes are chained through the DECL_CHAIN field, so this
4132 actually is the head of this parameter list. */
4134 /* Non-null for subprograms containing parameters passed by copy-in
4135 copy-out (Ada In Out or Out parameters not passed by reference),
4136 in which case it is the list of nodes used to specify the values
4137 of the In Out/Out parameters that are returned as a record upon
4138 procedure return. The TREE_PURPOSE of an element of this list is
4139 a field of the record and the TREE_VALUE is the PARM_DECL
4140 corresponding to that field. This list will be saved in the
4141 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
4143 /* List of fields in return type of procedure with copy-in copy-out
4144 parameters. */
4146 /* If an import pragma asks to map this subprogram to a GCC builtin,
4147 this is the builtin DECL node. */
4150 Entity_Id gnat_param;
4151 enum inline_status_t inline_status
4153 ? is_suppressed
4155 ? is_required
4158 bool extern_flag
4161 /* The semantics of "pure" in Ada essentially matches that of "const"
4162 in the back-end. In particular, both properties are orthogonal to
4163 the "nothrow" property if the EH circuitry is explicit in the
4164 internal representation of the back-end. If we are to completely
4165 hide the EH circuitry from it, we need to declare that calls to pure
4166 Ada subprograms that can throw have side effects since they can
4167 trigger an "abnormal" transfer of control flow; thus they can be
4168 neither "const" nor "pure" in the back-end sense. */
4169 bool const_flag
4178 /* A parameter may refer to this type, so defer completion of any
4179 incomplete types. */
4181 {
4182 defer_incomplete_level++;
4184 }
4186 /* If the subprogram has an alias, it is probably inherited, so
4187 we can use the original one. If the original "subprogram"
4188 is actually an enumeration literal, it may be the first use
4189 of its type, so we must elaborate that type now. */
4191 {
4197 /* Elaborate any Itypes in the parameters of this entity. */
4205 }
4207 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
4208 corresponding DECL node. Proper generation of calls later on need
4209 proper parameter associations so we don't "break;" here. */
4212 {
4215 /* Inability to find the builtin decl most often indicates a
4216 genuine mistake, but imports of unregistered intrinsics are
4217 sometimes issued on purpose to allow hooking in alternate
4218 bodies. We post a warning conditioned on Wshadow in this case,
4219 to let developers be notified on demand without risking false
4220 positives with common default sets of options. */
4224 }
4226 /* ??? What if we don't find the builtin node above ? warn ? err ?
4227 In the current state we neither warn nor err, and calls will just
4228 be handled as for regular subprograms. */
4230 /* Look into the return type and get its associated GCC tree. If it
4231 is not void, compute various flags for the subprogram type. */
4234 else
4235 {
4236 /* Ada 2012 (AI05-0151): Incomplete types coming from a limited
4237 context may now appear in parameter and result profiles. If
4238 we are only annotating types, break circularities here. */
4242 && In_Extended_Main_Code_Unit
4246 else
4249 /* If this function returns by reference, make the actual return
4250 type the pointer type and make a note of that. */
4252 {
4255 }
4257 /* If we are supposed to return an unconstrained array type, make
4258 the actual return type the fat pointer type. */
4260 {
4263 }
4265 /* Likewise, if the return type requires a transient scope, the
4266 return value will be allocated on the secondary stack so the
4267 actual return type is the pointer type. */
4269 {
4272 }
4274 /* If the Mechanism is By_Reference, ensure this function uses the
4275 target's by-invisible-reference mechanism, which may not be the
4276 same as above (e.g. it might be passing an extra parameter). */
4281 /* Likewise, if the return type is itself By_Reference. */
4285 /* If the type is a padded type and the underlying type would not
4286 be passed by reference or the function has a foreign convention,
4287 return the underlying type. */
4289 && (!default_pass_by_ref
4294 /* If the return type is unconstrained, that means it must have a
4295 maximum size. Use the padded type as the effective return type.
4296 And ensure the function uses the target's by-invisible-reference
4297 mechanism to avoid copying too much data when it returns. */
4299 {
4302 gnu_return_type
4308 /* Declare it now since it will never be declared otherwise.
4309 This is necessary to ensure that its subtrees are properly
4310 marked. */
4315 gnat_entity);
4318 }
4320 /* If the return type has a size that overflows, we cannot have
4321 a function that returns that type. This usage doesn't make
4322 sense anyway, so give an error here. */
4326 {
4328 gnat_entity);
4334 }
4335 }
4337 /* Loop over the parameters and get their associated GCC tree. While
4338 doing this, build a copy-in copy-out structure if we need one. */
4342 {
4349 /* Ada 2012 (AI05-0151): Incomplete types coming from a limited
4350 context may now appear in parameter and result profiles. If
4351 we are only annotating types, break circularities here. */
4355 && In_Extended_Main_Code_Unit
4358 {
4361 }
4362 else
4363 {
4366 }
4368 /* Builtins are expanded inline and there is no real call sequence
4369 involved. So the type expected by the underlying expander is
4370 always the type of each argument "as is". */
4373 /* Handle the first parameter of a valued procedure specially. */
4376 /* Otherwise, see if a Mechanism was supplied that forced this
4377 parameter to be passed one way or another. */
4381 ;
4383 {
4387 mech))
4389 else
4391 }
4392 else
4393 {
4396 }
4398 /* Do not call gnat_to_gnu_param for a fake parameter type since
4399 it will try to use the real type again. */
4401 {
4404 else
4405 {
4406 gnu_param
4413 }
4414 }
4415 else
4416 gnu_param
4421 /* We are returned either a PARM_DECL or a type if no parameter
4422 needs to be passed; in either case, adjust the type. */
4425 else
4426 {
4429 }
4431 /* The failure of this assertion will very likely come from an
4432 order of elaboration issue for the type of the parameter. */
4438 {
4444 /* If a parameter is a pointer, this function may modify
4445 memory through it and thus shouldn't be considered
4446 a const function. Also, the memory may be modified
4447 between two calls, so they can't be CSE'ed. The latter
4448 case also handles by-ref parameters. */
4452 }
4455 {
4457 {
4460 /* If this is a function, we also need a field for the
4461 return value to be placed. */
4463 {
4464 gnu_field
4466 gnu_return_type,
4472 gnu_cico_list
4474 }
4478 /* Set a default alignment to speed up accesses. But we
4479 shouldn't increase the size of the structure too much,
4480 lest it doesn't fit in return registers anymore. */
4483 }
4485 gnu_field
4493 gnu_cico_list
4495 }
4496 }
4499 {
4500 /* If we have a CICO list but it has only one entry, we convert
4501 this function into a function that returns this object. */
4505 /* Do not finalize the return type if the subprogram is stubbed
4506 since structures are incomplete for the back-end. */
4508 {
4512 /* Try to promote the mode of the return type if it is passed
4513 in registers, again to speed up accesses. */
4516 NULL_TREE))
4517 {
4518 unsigned int size
4521 machine_mode mode;
4527 {
4535 }
4536 }
4540 }
4541 }
4543 /* Deal with platform-specific calling conventions. */
4545 prepend_one_attribute
4548 gnat_entity);
4550 prepend_one_attribute
4553 gnat_entity);
4555 /* If we should request stack realignment for a foreign convention
4556 subprogram, do so. Note that this applies to task entry points
4557 in particular. */
4560 prepend_one_attribute
4563 gnat_entity);
4565 /* Deal with a pragma Linker_Section on a subprogram. */
4571 /* The lists have been built in reverse. */
4577 || return_by_direct_ref_p
4578 || return_by_invisi_ref_p
4580 gnu_type
4583 return_by_direct_ref_p,
4584 return_by_invisi_ref_p);
4586 /* A subprogram (something that doesn't return anything) shouldn't
4587 be considered const since there would be no reason for such a
4588 subprogram. Note that procedures with Out (or In Out) parameters
4589 have already been converted into a function with a return type. */
4594 {
4595 const int quals
4600 }
4602 /* If we have a builtin decl for that function, use it. Check if the
4603 profiles are compatible and warn if they are not. The checker is
4604 expected to post extra diagnostics in this case. */
4606 {
4607 intrin_binding_t inb;
4614 post_error
4616 gnat_entity);
4621 }
4623 /* If there was no specified Interface_Name and the external and
4624 internal names of the subprogram are the same, only use the
4625 internal name to allow disambiguation of nested subprograms. */
4630 /* If we are defining the subprogram and it has an Address clause
4631 we must get the address expression from the saved GCC tree for the
4632 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4633 the address expression here since the front-end has guaranteed
4634 in that case that the elaboration has no effects. If there is
4635 an Address clause and we are not defining the object, just
4636 make it a constant. */
4638 {
4642 gnu_address
4649 /* Convert the type of the object to a reference type that can
4650 alias everything as per 13.3(19). */
4651 gnu_type
4656 gnu_decl
4661 }
4664 {
4666 gnu_decl
4669 }
4670 else
4671 {
4672 gnu_decl
4677 /* This is unrelated to the stub built right above. */
4680 }
4681 }
4692 {
4693 /* Get the "full view" of this entity. If this is an incomplete
4694 entity from a limited with, treat its non-limited view as the
4695 full view. Otherwise, use either the full view or the underlying
4696 full view, whichever is present. This is used in all the tests
4697 below. */
4698 Entity_Id full_view
4707 /* If this is an incomplete type with no full view, it must be a Taft
4708 Amendment type, in which case we return a dummy type. Otherwise,
4709 just get the type from its Etype. */
4711 {
4713 {
4716 }
4717 else
4718 {
4722 }
4724 }
4726 /* If we already made a type for the full view, reuse it. */
4728 {
4731 }
4733 /* Otherwise, if we are not defining the type now, get the type
4734 from the full view. But always get the type from the full view
4735 for define on use types, since otherwise we won't see them! */
4739 {
4743 }
4745 /* For incomplete types, make a dummy type entry which will be
4746 replaced later. Save it as the full declaration's type so
4747 we can do any needed updates when we see it. */
4754 }
4757 /* Class-wide types are always transformed into their root type. */
4766 /* Concurrent types are always transformed into their record type. */
4769 else
4780 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4781 we've already saved it, so we don't try to. */
4787 /* This is a SPARK annotation that only reaches here when compiling in
4788 ASIS mode and has no characteristics to annotate. */
4794 }
4796 /* If we had a case where we evaluated another type and it might have
4797 defined this one, handle it here. */
4799 {
4802 }
4804 /* If we are processing a type and there is either no decl for it or
4805 we just made one, do some common processing for the type, such as
4806 handling alignment and possible padding. */
4808 {
4809 /* Process the attributes, if not already done. Note that the type is
4810 already defined so we cannot pass true for IN_PLACE here. */
4813 /* Tell the middle-end that objects of tagged types are guaranteed to
4814 be properly aligned. This is necessary because conversions to the
4815 class-wide type are translated into conversions to the root type,
4816 which can be less aligned than some of its derived types. */
4821 /* Record whether the type is passed by reference. */
4825 /* ??? Don't set the size for a String_Literal since it is either
4826 confirming or we don't handle it properly (if the low bound is
4827 non-constant). */
4829 {
4832 gnu_size
4835 }
4837 /* If a size was specified, see if we can make a new type of that size
4838 by rearranging the type, for example from a fat to a thin pointer. */
4840 {
4841 gnu_type
4848 }
4850 /* If the alignment has not already been processed and this is not
4851 an unconstrained array type, see if an alignment is specified.
4852 If not, we pick a default alignment for atomic objects. */
4854 ;
4856 {
4860 /* Warn on suspiciously large alignments. This should catch
4861 errors about the (alignment,byte)/(size,bit) discrepancy. */
4863 {
4864 tree size;
4866 /* If a size was specified, take it into account. Otherwise
4867 use the RM size for records or unions as the type size has
4868 already been adjusted to the alignment. */
4874 else
4877 /* Consider an alignment as suspicious if the alignment/size
4878 ratio is greater or equal to the byte/bit ratio. */
4883 gnat_entity);
4884 }
4885 }
4896 /* See if we need to pad the type. If we did, and made a record,
4897 the name of the new type may be changed. So get it back for
4898 us when we make the new TYPE_DECL below. */
4906 /* Now set the RM size of the type. We cannot do it before padding
4907 because we need to accept arbitrary RM sizes on integral types. */
4910 /* If we are at global level, GCC will have applied variable_size to
4911 the type, but that won't have done anything. So, if it's not
4912 a constant or self-referential, call elaborate_expression_1 to
4913 make a variable for the size rather than calculating it each time.
4914 Handle both the RM size and the actual size. */
4919 {
4927 /* ??? For now, store the size as a multiple of the alignment in
4928 bytes so that we can see the alignment from the tree. */
4935 /* ??? gnu_type may come from an existing type so the MULT_EXPR node
4936 may not be marked by the call to create_type_decl below. */
4940 {
4945 {
4949 /* If the position of the variant part is constant, subtract
4950 it from the size of the type of the parent to get the new
4951 size. This manual CSE reduces the data size. */
4953 {
4961 }
4962 else
4963 {
4966 gnat_entity,
4970 /* ??? For now, store the size as a multiple of the
4971 alignment in bytes so that we can see the alignment
4972 from the tree. */
4975 gnat_entity,
4976 get_identifier
4981 /* ??? For now, store the offset as a multiple of the
4982 alignment in bytes so that we can see the alignment
4983 from the tree. */
4986 gnat_entity,
4989 DECL_OFFSET_ALIGN
4991 }
4995 }
4999 else
5000 ada_size
5005 }
5006 }
5008 /* If this is a record type or subtype, call elaborate_expression_2 on
5009 any field position. Do this for both global and local types.
5010 Skip any fields that we haven't made trees for to avoid problems with
5011 class wide types. */
5016 {
5019 /* ??? For now, store the offset as a multiple of the alignment
5020 in bytes so that we can see the alignment from the tree. */
5022 {
5025 gnat_temp,
5030 /* ??? The context of gnu_field is not necessarily gnu_type
5031 so the MULT_EXPR node built above may not be marked by
5032 the call to create_type_decl below. */
5035 }
5036 }
5041 /* If this is not an unconstrained array type, set some flags. */
5043 {
5052 }
5058 else
5059 {
5062 }
5063 }
5066 {
5069 /* If this is a derived type, relate its alias set to that of its parent
5070 to avoid troubles when a call to an inherited primitive is inlined in
5071 a context where a derived object is accessed. The inlined code works
5072 on the parent view so the resulting code may access the same object
5073 using both the parent and the derived alias sets, which thus have to
5074 conflict. As the same issue arises with component references, the
5075 parent alias set also has to conflict with composite types enclosing
5076 derived components. For instance, if we have:
5078 type D is new T;
5079 type R is record
5080 Component : D;
5081 end record;
5083 we want T to conflict with both D and R, in addition to R being a
5084 superset of D by record/component construction.
5086 One way to achieve this is to perform an alias set copy from the
5087 parent to the derived type. This is not quite appropriate, though,
5088 as we don't want separate derived types to conflict with each other:
5090 type I1 is new Integer;
5091 type I2 is new Integer;
5093 We want I1 and I2 to both conflict with Integer but we do not want
5094 I1 to conflict with I2, and an alias set copy on derivation would
5095 have that effect.
5097 The option chosen is to make the alias set of the derived type a
5098 superset of that of its parent type. It trivially fulfills the
5099 simple requirement for the Integer derivation example above, and
5100 the component case as well by superset transitivity:
5102 superset superset
5103 R ----------> D ----------> T
5105 However, for composite types, conversions between derived types are
5106 translated into VIEW_CONVERT_EXPRs so a sequence like:
5108 type Comp1 is new Comp;
5109 type Comp2 is new Comp;
5110 procedure Proc (C : Comp1);
5112 C : Comp2;
5113 Proc (Comp1 (C));
5115 is translated into:
5117 C : Comp2;
5118 Proc ((Comp1 &) &VIEW_CONVERT_EXPR <Comp1> (C));
5120 and gimplified into:
5122 C : Comp2;
5123 Comp1 *C.0;
5124 C.0 = (Comp1 *) &C;
5125 Proc (C.0);
5127 i.e. generates code involving type punning. Therefore, Comp1 needs
5128 to conflict with Comp2 and an alias set copy is required.
5130 The language rules ensure the parent type is already frozen here. */
5132 {
5134 /* For constrained packed array subtypes, the implementation type is
5135 used instead of the nominal type. */
5143 }
5145 /* Back-annotate the Alignment of the type if not already in the
5146 tree. Likewise for sizes. */
5148 {
5152 /* If the default alignment of "double" or larger scalar types is
5153 specifically capped and this is not an array with an alignment
5154 clause on the component type, return the cap. */
5156 is_capped_double
5159 is_capped_double
5161 else
5166 else
5170 }
5173 {
5176 /* If the size is self-referential, annotate the maximum value. */
5180 /* If we are just annotating types and the type is tagged, the tag
5181 and the parent components are not generated by the front-end so
5182 sizes must be adjusted if there is no representation clause. */
5188 {
5190 Uint uint_size;
5193 {
5197 }
5198 else
5202 offset
5210 }
5211 else
5213 }
5217 }
5219 /* If we really have a ..._DECL node, set a couple of flags on it. But we
5220 cannot do so if we are reusing the ..._DECL node made for an equivalent
5221 type or an alias or a renamed object as the predicates don't apply to it
5222 but to GNAT_ENTITY. */
5227 {
5233 }
5235 /* If we haven't already, associate the ..._DECL node that we just made with
5236 the input GNAT entity node. */
5240 /* Now we are sure gnat_entity has a corresponding ..._DECL node,
5241 eliminate as many deferred computations as possible. */
5244 /* If this is an enumeration or floating-point type, we were not able to set
5245 the bounds since they refer to the type. These are always static. */
5248 {
5252 /* If this is a padded type, we need to use the underlying type. */
5256 /* If this is a floating point type and we haven't set a floating
5257 point type yet, use this in the evaluation of the bounds. */
5265 {
5266 /* Enumeration types have specific RM bounds. */
5269 }
5270 else
5271 {
5272 /* Floating-point types don't have specific RM bounds. */
5275 }
5276 }
5278 /* If we deferred processing of incomplete types, re-enable it. If there
5279 were no other disables and we have deferred types to process, do so. */
5283 {
5286 /* We are back to level 0 for the deferring of incomplete types.
5287 But processing these incomplete types below may itself require
5288 deferring, so preserve what we have and restart from scratch. */
5293 {
5300 }
5301 }
5303 /* If we are not defining this type, see if it's on one of the lists of
5304 incomplete types. If so, handle the list entry now. */
5306 {
5311 {
5315 }
5319 {
5323 }
5324 }
5327 force_global--;
5329 /* If this is a packed array type whose original array type is itself
5330 an Itype without freeze node, make sure the latter is processed. */
5338 }
5340 /* Similar, but if the returned value is a COMPONENT_REF, return the
5341 FIELD_DECL. */
5343 tree
5345 {
5352 }
5354 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5355 the GCC type corresponding to that entity. */
5357 tree
5359 {
5360 tree gnu_decl;
5362 /* The back end never attempts to annotate generic types. */
5370 }
5372 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5373 the unpadded version of the GCC type corresponding to that entity. */
5375 tree
5377 {
5384 }
5386 /* Return the DECL associated with the public subprogram GNAT_ENTITY but whose
5387 type has been changed to that of the parameterless procedure, except if an
5388 alias is already present, in which case it is returned instead. */
5390 tree
5392 {
5396 /* See the E_Function/E_Procedure case of gnat_to_gnu_entity for the model
5397 of the handling applied here. */
5400 {
5404 }
5412 gnat_entity);
5416 gnat_entity);
5421 return
5424 }
5426 /* Return whether the E_Subprogram_Type/E_Function/E_Procedure GNAT_ENTITY is
5427 a C++ imported method or equivalent.
5429 We use the predicate on 32-bit x86/Windows to find out whether we need to
5430 use the "thiscall" calling convention for GNAT_ENTITY. This convention is
5431 used for C++ methods (functions with METHOD_TYPE) by the back-end. */
5433 bool
5435 {
5439 /* This is the main case: C++ method imported as a primitive operation. */
5443 /* A thunk needs to be handled like its associated primitive operation. */
5447 /* C++ classes with no virtual functions can be imported as limited
5448 record types, but we need to return true for the constructors. */
5452 /* This is set on the E_Subprogram_Type built for a dispatching call. */
5457 }
5459 /* Finalize the processing of From_Limited_With incomplete types. */
5461 void
5463 {
5470 {
5477 }
5478 }
5480 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
5481 kind of type (such E_Task_Type) that has a different type which Gigi
5482 uses for its representation. If the type does not have a special type
5483 for its representation, return GNAT_ENTITY. If a type is supposed to
5484 exist, but does not, abort unless annotating types, in which case
5485 return Empty. If GNAT_ENTITY is Empty, return Empty. */
5487 Entity_Id
5489 {
5496 {
5520 }
5525 }
5527 /* Return a GCC tree for a type corresponding to the component type of the
5528 array type or subtype GNAT_ARRAY. DEFINITION is true if this component
5529 is for an array being defined. DEBUG_INFO_P is true if we need to write
5530 debug information for other types that we may create in the process. */
5532 static tree
5535 {
5538 tree gnu_comp_size;
5540 /* Try to get a smaller form of the component if needed. */
5554 /* Get and validate any specified Component_Size. */
5555 gnu_comp_size
5560 /* If the array has aliased components and the component size can be zero,
5561 force at least unit size to ensure that the components have distinct
5562 addresses. */
5568 gnu_comp_size
5571 /* If the component type is a RECORD_TYPE that has a self-referential size,
5572 then use the maximum size for the component size. */
5578 /* Honor the component size. This is not needed for bit-packed arrays. */
5580 {
5584 /* If an alignment is specified, use it as a cap on the component type
5585 so that it can be honored for the whole type. But ignore it for the
5586 original type of packed array types. */
5590 else
5596 else
5602 /* If a padding record was made, declare it now since it will never be
5603 declared otherwise. This is necessary to ensure that its subtrees
5604 are properly marked. */
5607 gnat_array);
5608 }
5614 }
5616 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
5617 using MECH as its passing mechanism, to be placed in the parameter
5618 list built for GNAT_SUBPROG. Assume a foreign convention for the
5619 latter if FOREIGN is true. Also set CICO to true if the parameter
5620 must use the copy-in copy-out implementation mechanism.
5622 The returned tree is a PARM_DECL, except for those cases where no
5623 parameter needs to be actually passed to the subprogram; the type
5624 of this "shadow" parameter is then returned instead. */
5626 static tree
5629 {
5633 /* The parameter can be indirectly modified if its address is taken. */
5637 tree gnu_param;
5639 /* Copy-return is used only for the first parameter of a valued procedure.
5640 It's a copy mechanism for which a parameter is never allocated. */
5642 {
5646 }
5648 /* If this is either a foreign function or if the underlying type won't
5649 be passed by reference, strip off possible padding type. */
5651 {
5655 || foreign
5659 }
5661 /* If this is a read-only parameter, make a variant of the type that is
5662 read-only. ??? However, if this is an unconstrained array, that type
5663 can be very complex, so skip it for now. Likewise for any other
5664 self-referential type. */
5670 /* For foreign conventions, pass arrays as pointers to the element type.
5671 First check for unconstrained array and get the underlying array. */
5673 gnu_param_type
5676 /* For GCC builtins, pass Address integer types as (void *) */
5682 /* Arrays are passed as pointers to element type for foreign conventions. */
5684 {
5685 /* Strip off any multi-dimensional entries, then strip
5686 off the last array to get the component type. */
5695 gnu_param_type
5699 }
5701 /* Fat pointers are passed as thin pointers for foreign conventions. */
5703 gnu_param_type
5706 /* If we must pass or were requested to pass by reference, do so.
5707 If we were requested to pass by copy, do so.
5708 Otherwise, for foreign conventions, pass In Out or Out parameters
5709 or aggregates by reference. For COBOL and Fortran, pass all
5710 integer and FP types that way too. For Convention Ada, use
5711 the standard Ada default. */
5715 && ((foreign
5717 || (foreign
5722 || (!foreign
5724 {
5725 /* We take advantage of 6.2(12) by considering that references built for
5726 parameters whose type isn't by-ref and for which the mechanism hasn't
5727 been forced to by-ref are restrict-qualified in the C sense. */
5728 bool restrict_p
5732 gnu_param_type
5735 }
5737 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
5744 /* If this is an Out parameter that isn't passed by reference and isn't
5745 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
5746 it will be a VAR_DECL created when we process the procedure, so just
5747 return its type. For the special parameter of a valued procedure,
5748 never pass it in.
5750 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
5751 Out parameters with discriminants or implicit initial values to be
5752 handled like In Out parameters. These type are normally built as
5753 aggregates, hence passed by reference, except for some packed arrays
5754 which end up encoded in special integer types. Note that scalars can
5755 be given implicit initial values using the Default_Value aspect.
5757 The exception we need to make is then for packed arrays of records
5758 with discriminants or implicit initial values. We have no light/easy
5759 way to check for the latter case, so we merely check for packed arrays
5760 of records. This may lead to useless copy-in operations, but in very
5761 rare cases only, as these would be exceptions in a set of already
5762 exceptional situations. */
5764 && !by_ref
5765 && (by_return
5782 /* If no Mechanism was specified, indicate what we're using, then
5783 back-annotate it. */
5789 }
5791 /* Like build_qualified_type, but TYPE_QUALS is added to the existing
5792 qualifiers on TYPE. */
5794 static tree
5796 {
5798 }
5800 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
5802 static bool
5804 {
5811 return
5813 }
5815 /* Return true if the array type GNU_TYPE, which represents a dimension of
5816 GNAT_TYPE, has a non-aliased component in the back-end sense. */
5818 static bool
5820 {
5821 /* If the array type is not the innermost dimension of the GNAT type,
5822 then it has a non-aliased component. */
5827 /* If the array type has an aliased component in the front-end sense,
5828 then it also has an aliased component in the back-end sense. */
5832 /* If this is a derived type, then it has a non-aliased component if
5833 and only if its parent type also has one. */
5835 {
5839 gnu_parent_type
5844 }
5846 /* Otherwise, rely exclusively on properties of the element type. */
5848 }
5850 /* Return true if GNAT_ADDRESS is a value known at compile-time. */
5852 static bool
5854 {
5855 /* Catch System'To_Address. */
5860 }
5862 /* Return true if GNAT_RANGE, a N_Range node, cannot be superflat, i.e. if the
5863 inequality HB >= LB-1 is true. LB and HB are the low and high bounds. */
5865 static bool
5867 {
5869 Node_Id scalar_range;
5872 /* If the low bound is not constant, try to find an upper bound. */
5881 /* If the high bound is not constant, try to find a lower bound. */
5890 /* If we have failed to find constant bounds, punt. */
5895 /* We need at least a signed 64-bit type to catch most cases. */
5901 /* If the low bound is the smallest integer, nothing can be smaller. */
5907 }
5909 /* Return true if GNU_EXPR is (essentially) the address of a CONSTRUCTOR. */
5911 static bool
5913 {
5921 }
5922 \f
5923 /* Given GNAT_ENTITY, elaborate all expressions that are required to
5924 be elaborated at the point of its definition, but do nothing else. */
5926 void
5928 {
5930 {
5937 {
5941 /* ??? Tests to avoid Constraint_Error in static expressions
5942 are needed until after the front stops generating bogus
5943 conversions on bounds of real types. */
5951 }
5958 {
5959 Node_Id gnat_discriminant_expr;
5960 Entity_Id gnat_field;
5964 gnat_discriminant_expr
5969 /* Ignore access discriminants. */
5974 }
5977 }
5978 }
5979 \f
5980 /* Return true if the size in units represented by GNU_SIZE can be handled by
5981 an allocation. If STATIC_P is true, consider only what can be done with a
5982 static allocation. */
5984 static bool
5986 {
5987 /* We can allocate a fixed size if it is a valid for the middle-end. */
5991 /* We can allocate a variable size if this isn't a static allocation. */
5992 else
5994 }
5995 \f
5996 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
5997 NAME, ARGS and ERROR_POINT. */
5999 static void
6002 tree attr_name,
6003 tree attr_args,
6004 Node_Id attr_error_point)
6005 {
6015 }
6017 /* Prepend to ATTR_LIST an entry for an attribute provided by GNAT_PRAGMA. */
6019 static void
6021 {
6026 /* Map the pragma at hand. Skip if this isn't one we know how to handle. */
6028 {
6059 }
6061 /* See what arguments we have and turn them into GCC trees for attribute
6062 handlers. These expect identifier for strings. We handle at most two
6063 arguments and static expressions only. */
6065 {
6071 {
6075 {
6079 }
6082 }
6086 {
6091 }
6092 }
6094 /* Prepend to the list. Make a list of the argument we might have, as GCC
6095 expects it. */
6097 gnu_arg1
6101 }
6103 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
6105 static void
6107 {
6108 Node_Id gnat_temp;
6110 /* Attributes are stored as Representation Item pragmas. */
6116 }
6117 \f
6118 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
6119 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
6120 return the GCC tree to use for that expression. GNU_NAME is the suffix
6121 to use if a variable needs to be created and DEFINITION is true if this
6122 is a definition of GNAT_ENTITY. If NEED_VALUE is true, we need a result;
6123 otherwise, we are just elaborating the expression for side-effects. If
6124 NEED_DEBUG is true, we need a variable for debugging purposes even if it
6125 isn't needed for code generation. */
6127 static tree
6130 {
6131 tree gnu_expr;
6133 /* If we already elaborated this expression (e.g. it was involved
6134 in the definition of a private type), use the old value. */
6138 /* If we don't need a value and this is static or a discriminant,
6139 we don't need to do anything. */
6146 /* If it's a static expression, we don't need a variable for debugging. */
6150 /* Otherwise, convert this tree to its GCC equivalent and elaborate it. */
6154 /* Save the expression in case we try to elaborate this entity again. Since
6155 it's not a DECL, don't check it. Don't save if it's a discriminant. */
6160 }
6162 /* Similar, but take a GNU expression and always return a result. */
6164 static tree
6167 {
6172 /* In most cases, we won't see a naked FIELD_DECL because a discriminant
6173 reference will have been replaced with a COMPONENT_REF when the type
6174 is being elaborated. However, there are some cases involving child
6175 types where we will. So convert it to a COMPONENT_REF. We hope it
6176 will be at the highest level of the expression in these cases. */
6182 /* If GNU_EXPR contains a placeholder, just return it. We rely on the fact
6183 that an expression cannot contain both a discriminant and a variable. */
6187 /* If GNU_EXPR is neither a constant nor based on a read-only variable, make
6188 a variable that is initialized to contain the expression when the package
6189 containing the definition is elaborated. If this entity is defined at top
6190 level, replace the expression by the variable; otherwise use a SAVE_EXPR
6191 if this is necessary. */
6194 else
6195 {
6196 /* Skip any conversions and simple constant arithmetics to see if the
6197 expression is based on a read-only variable.
6198 ??? This really should remain read-only, but we have to think about
6199 the typing of the tree here. */
6205 {
6207 tree offset;
6208 machine_mode mode;
6213 /* If the offset is variable, err on the side of caution. */
6216 }
6218 expr_variable_p
6219 = !(inner
6222 }
6224 /* We only need to use the variable if we are in a global context since GCC
6225 can do the right thing in the local case. However, when not optimizing,
6226 use it for bounds of loop iteration scheme to avoid code duplication. */
6227 use_variable = expr_variable_p
6228 && (expr_global_p
6229 || (!optimize
6230 && definition
6235 /* Now create it, possibly only for debugging purposes. */
6237 {
6238 /* The following variable creation can happen when processing the body of
6239 subprograms that are defined out of the extended main unit and
6240 inlined. In this case, we are not at the global scope, and thus the
6241 new variable must not be tagged "external", as we used to do here as
6242 long as definition == 0. */
6244 tree gnu_decl
6245 = create_var_decl_1
6252 /* Using this variable at debug time (if need_debug is true) requires a
6253 proper location. The back-end will compute a location for this
6254 variable only if the variable is used by the generated code.
6255 Returning the variable ensures the caller will use it in generated
6256 code. Note that there is no need for a location if the debug info
6257 contains an integer constant.
6258 FIXME: when the encoding-based debug scheme is dropped, move this
6259 condition to the top-level IF block: we will not need to create a
6260 variable anymore in such cases, then. */
6263 }
6266 }
6268 /* Similar, but take an alignment factor and make it explicit in the tree. */
6270 static tree
6273 {
6275 return
6278 gnu_expr,
6279 unit_align),
6281 need_debug),
6282 unit_align);
6283 }
6284 \f
6285 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
6286 the value passed against the list of choices. */
6288 tree
6290 {
6291 Node_Id choice;
6292 Node_Id gnat_temp;
6297 {
6299 {
6304 this_test
6318 this_test
6328 /* This represents either a subtype range, an enumeration
6329 literal, or a constant Ekind says which. If an enumeration
6330 literal or constant, fall through to the next case. */
6333 {
6339 this_test
6346 }
6348 /* ... fall through ... */
6354 single);
6363 }
6366 this_test);
6367 }
6370 }
6371 \f
6372 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
6373 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
6375 static int
6377 {
6378 /* If the field contains an item of variable size, we cannot pack it
6379 because we cannot create temporaries of non-fixed size in case
6380 we need to take the address of the field. See addressable_p and
6381 the notes on the addressability issues for further details. */
6385 /* If the alignment of the record is specified and the field type
6386 is over-aligned, request Storage_Unit alignment for the field. */
6388 {
6391 else
6393 }
6396 }
6398 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
6399 placed in GNU_RECORD_TYPE.
6401 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
6402 record has Component_Alignment of Storage_Unit, -2 if the enclosing
6403 record has a specified alignment.
6405 DEFINITION is true if this field is for a record being defined.
6407 DEBUG_INFO_P is true if we need to write debug information for types
6408 that we may create in the process. */
6410 static tree
6413 {
6418 bool is_aliased
6420 bool is_atomic
6422 bool is_volatile
6424 bool needs_strict_alignment
6427 /* If this field requires strict alignment, we cannot pack it because
6428 it would very likely be under-aligned in the record. */
6431 else
6434 /* If a size is specified, use it. Otherwise, if the record type is packed,
6435 use the official RM size. See "Handling of Type'Size Values" in Einfo
6436 for further details. */
6443 else
6446 /* If we have a specified size that is smaller than that of the field's type,
6447 or a position is specified, and the field's type is a record that doesn't
6448 require strict alignment, see if we can get either an integral mode form
6449 of the type or a smaller form. If we can, show a size was specified for
6450 the field if there wasn't one already, so we know to make this a bitfield
6451 and avoid making things wider.
6453 Changing to an integral mode form is useful when the record is packed as
6454 we can then place the field at a non-byte-aligned position and so achieve
6455 tighter packing. This is in addition required if the field shares a byte
6456 with another field and the front-end lets the back-end handle the access
6457 to the field, because GCC cannot handle non-byte-aligned BLKmode fields.
6459 Changing to a smaller form is required if the specified size is smaller
6460 than that of the field's type and the type contains sub-fields that are
6461 padded, in order to avoid generating accesses to these sub-fields that
6462 are wider than the field.
6464 We avoid the transformation if it is not required or potentially useful,
6465 as it might entail an increase of the field's alignment and have ripple
6466 effects on the outer record type. A typical case is a field known to be
6467 byte-aligned and not to share a byte with another field. */
6473 || (gnu_size
6479 {
6482 {
6486 }
6487 }
6493 {
6495 Entity_Id gnat_parent
6502 /* Ensure the position does not overlap with the parent subtype, if there
6503 is one. This test is omitted if the parent of the tagged type has a
6504 full rep clause since, in this case, component clauses are allowed to
6505 overlay the space allocated for the parent type and the front-end has
6506 checked that there are no overlapping components. */
6508 {
6513 post_error_ne_tree
6516 }
6518 /* If this field needs strict alignment, make sure that the record is
6519 sufficiently aligned and that the position and size are consistent
6520 with the type. But don't do it if we are just annotating types and
6521 the field's type is tagged, since tagged types aren't fully laid out
6522 in this mode. Also, note that atomic implies volatile so the inner
6523 test sequences ordering is significant here. */
6526 {
6532 /* If the position is not a multiple of the alignment of the type,
6533 then error out and reset the position. */
6536 {
6548 else
6552 type_align);
6554 }
6557 {
6561 /* If the size is lower than that of the type, or greater for
6562 atomic and aliased, then error out and reset the size. */
6564 {
6576 else
6580 gnu_type_size);
6582 }
6584 /* Likewise if the size is not a multiple of a byte, */
6586 bitsize_unit_node)))
6587 {
6596 else
6601 }
6602 }
6603 }
6604 }
6606 /* If the record has rep clauses and this is the tag field, make a rep
6607 clause for it as well. */
6610 {
6613 }
6615 else
6616 {
6619 /* If we are packing the record and the field is BLKmode, round the
6620 size up to a byte boundary. */
6623 }
6625 /* We need to make the size the maximum for the type if it is
6626 self-referential and an unconstrained type. In that case, we can't
6627 pack the field since we can't make a copy to align it. */
6629 && !gnu_size
6632 {
6635 }
6637 /* If a size is specified, adjust the field's type to it. */
6639 {
6640 tree orig_field_type;
6642 /* If the field's type is justified modular, we would need to remove
6643 the wrapper to (better) meet the layout requirements. However we
6644 can do so only if the field is not aliased to preserve the unique
6645 layout and if the prescribed size is not greater than that of the
6646 packed array to preserve the justification. */
6654 /* Similarly if the field's type is a misaligned integral type, but
6655 there is no restriction on the size as there is no justification. */
6661 gnu_field_type
6669 /* If a padding record was made, declare it now since it will never be
6670 declared otherwise. This is necessary to ensure that its subtrees
6671 are properly marked. */
6676 }
6678 /* Otherwise (or if there was an error), don't specify a position. */
6679 else
6685 /* Now create the decl for the field. */
6686 gnu_field
6698 }
6699 \f
6700 /* Return true if at least one member of COMPONENT_LIST needs strict
6701 alignment. */
6703 static bool
6705 {
6706 Node_Id component_decl;
6711 {
6719 }
6722 }
6724 /* Return true if TYPE is a type with variable size or a padding type with a
6725 field of variable size or a record that has a field with such a type. */
6727 static bool
6729 {
6730 tree field;
6747 }
6748 \f
6749 /* Return true if FIELD is an artificial field. */
6751 static bool
6753 {
6754 /* These fields are generated by the front-end proper. */
6758 /* These fields are generated by gigi. */
6763 }
6765 /* Return true if FIELD is a non-artificial aliased field. */
6767 static bool
6769 {
6774 }
6776 /* Return true if FIELD is a non-artificial field with self-referential
6777 size. */
6779 static bool
6781 {
6789 }
6791 /* Return true if FIELD is a non-artificial field with variable size. */
6793 static bool
6795 {
6803 }
6805 /* qsort comparer for the bit positions of two record components. */
6807 static int
6809 {
6812 const int ret
6816 }
6818 /* Structure holding information for a given variant. */
6820 {
6821 /* The record type of the variant. */
6822 tree type;
6824 /* The name of the variant. */
6825 tree name;
6827 /* The qualifier of the variant. */
6828 tree qual;
6830 /* Whether the variant has a rep clause. */
6833 /* Whether the variant is packed. */
6838 /* Translate and chain the GNAT_COMPONENT_LIST to the GNU_FIELD_LIST, set the
6839 result as the field list of GNU_RECORD_TYPE and finish it up. Return true
6840 if GNU_RECORD_TYPE has a rep clause which affects the layout (see below).
6841 When called from gnat_to_gnu_entity during the processing of a record type
6842 definition, the GCC node for the parent, if any, will be the single field
6843 of GNU_RECORD_TYPE and the GCC nodes for the discriminants will be on the
6844 GNU_FIELD_LIST. The other calls to this function are recursive calls for
6845 the component list of a variant and, in this case, GNU_FIELD_LIST is empty.
6847 PACKED is 1 if this is for a packed record, -1 if this is for a record
6848 with Component_Alignment of Storage_Unit, -2 if this is for a record
6849 with a specified alignment.
6851 DEFINITION is true if we are defining this record type.
6853 CANCEL_ALIGNMENT is true if the alignment should be zeroed before laying
6854 out the record. This means the alignment only serves to force fields to
6855 be bitfields, but not to require the record to be that aligned. This is
6856 used for variants.
6858 ALL_REP is true if a rep clause is present for all the fields.
6860 UNCHECKED_UNION is true if we are building this type for a record with a
6861 Pragma Unchecked_Union.
6863 ARTIFICIAL is true if this is a type that was generated by the compiler.
6865 DEBUG_INFO is true if we need to write debug information about the type.
6867 MAYBE_UNUSED is true if this type may be unused in the end; this doesn't
6868 mean that its contents may be unused as well, only the container itself.
6870 REORDER is true if we are permitted to reorder components of this type.
6872 FIRST_FREE_POS, if nonzero, is the first (lowest) free field position in
6873 the outer record type down to this variant level. It is nonzero only if
6874 all the fields down to this level have a rep clause and ALL_REP is false.
6876 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
6877 with a rep clause is to be added; in this case, that is all that should
6878 be done with such fields and the return value will be false. */
6880 static bool
6887 {
6901 /* For each component referenced in a component declaration create a GCC
6902 field and add it to the list, skipping pragmas in the GNAT list. */
6909 {
6913 /* If present, the _Parent field must have been created as the single
6914 field of the record type. Put it before any other fields. */
6916 {
6919 }
6920 else
6921 {
6925 /* If this is the _Tag field, put it before any other fields. */
6929 /* If this is the _Controller field, put it before the other
6930 fields except for the _Tag or _Parent field. */
6932 {
6935 }
6937 /* If this is a regular field, put it after the other fields. */
6938 else
6939 {
6945 /* And record information for the final layout. */
6950 }
6951 }
6954 }
6956 /* At the end of the component list there may be a variant part. */
6959 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
6960 mutually exclusive and should go in the same memory. To do this we need
6961 to treat each variant as a record whose elements are created from the
6962 component list for the variant. So here we create the records from the
6963 lists for the variants and put them all into the QUAL_UNION_TYPE.
6964 If this is an Unchecked_Union, we make a UNION_TYPE instead or
6965 use GNU_RECORD_TYPE if there are no fields so far. */
6967 {
6971 tree gnu_var_name
6982 gnu_union_name
6985 /* Reuse the enclosing union if this is an Unchecked_Union whose fields
6986 are all in the variant part, to match the layout of C unions. There
6987 is an associated check below. */
6990 else
6991 {
6992 gnu_union_type
6998 }
7000 /* If all the fields down to this level have a rep clause, find out
7001 whether all the fields at this level also have one. If so, then
7002 compute the new first free position to be passed downward. */
7005 {
7007 gnu_field;
7010 {
7013 this_first_free_pos
7015 }
7016 else
7017 {
7020 }
7021 }
7023 /* We build the variants in two passes. The bulk of the work is done in
7024 the first pass, that is to say translating the GNAT nodes, building
7025 the container types and computing the associated properties. However
7026 we cannot finish up the container types during this pass because we
7027 don't know where the variant part will be placed until the end. */
7031 {
7036 vinfo_t vinfo;
7044 /* Set the alignment of the inner type in case we need to make
7045 inner objects into bitfields, but then clear it out so the
7046 record actually gets only the alignment required. */
7050 /* Similarly, if the outer record has a size specified and all
7051 the fields have a rep clause, we can propagate the size. */
7053 {
7057 }
7059 /* Add the fields into the record type for the variant. Note that
7060 we aren't sure to really use it at this point, see below. */
7061 has_rep
7065 unchecked_union,
7067 this_first_free_pos,
7068 all_rep || this_first_free_pos
7071 /* Translate the qualifier and annotate the GNAT node. */
7075 /* Deal with packedness like in gnat_to_gnu_field. */
7077 {
7080 }
7081 else
7082 field_packed
7085 /* Push this variant onto the stack for the second pass. */
7093 /* Compute the global properties that will determine the placement of
7094 the variant part. */
7098 }
7100 /* Round up the first free position to the alignment of the variant part
7101 for the variants without rep clause. This will guarantee a consistent
7102 layout independently of the placement of the variant part. */
7106 /* In the second pass, the container types are adjusted if necessary and
7107 finished up, then the corresponding fields of the variant part are
7108 built with their qualifier, unless this is an unchecked union. */
7110 {
7114 /* If this is an Unchecked_Union whose fields are all in the variant
7115 part and we have a single field with no representation clause or
7116 placed at offset zero, use the field directly to match the layout
7117 of C unions. */
7119 && gnu_field_list
7123 {
7126 }
7127 else
7128 {
7129 /* Finalize the variant type now. We used to throw away empty
7130 record types but we no longer do that because we need them to
7131 generate complete debug info for the variant; otherwise, the
7132 union type definition will be lacking the fields associated
7133 with these empty variants. */
7135 {
7136 /* The variant part will be at offset 0 so we need to ensure
7137 that the fields are laid out starting from the first free
7138 position at this level. */
7140 tree gnu_rep_part;
7142 gnu_rep_part
7144 this_first_free_pos);
7149 }
7156 gnu_field
7158 gnu_union_type,
7159 all_rep_and_size
7168 }
7172 }
7174 /* Only make the QUAL_UNION_TYPE if there are non-empty variants. */
7176 {
7180 {
7184 }
7189 /* If GNU_UNION_TYPE is our record type, it means we must have an
7190 Unchecked_Union with no fields. Verify that and, if so, just
7191 return. */
7193 {
7195 && !gnu_field_list
7198 }
7203 /* Deal with packedness like in gnat_to_gnu_field. */
7206 else
7207 union_field_packed
7210 gnu_variant_part
7212 all_rep_and_size
7218 }
7219 }
7221 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses and, if we are
7222 permitted to reorder components, self-referential sizes or variable sizes.
7223 If they do, pull them out and put them onto the appropriate list. We have
7224 to do this in a separate pass since we want to handle the discriminants
7225 but can't play with them until we've used them in debugging data above.
7227 Similarly, pull out the fields with zero size and no rep clause, as they
7228 would otherwise modify the layout and thus very likely run afoul of the
7229 Ada semantics, which are different from those of C here.
7231 ??? If we reorder them, debugging information will be wrong but there is
7232 nothing that can be done about this at the moment. */
7235 #define MOVE_FROM_FIELD_LIST_TO(LIST) \
7236 do { \
7237 if (gnu_last) \
7238 DECL_CHAIN (gnu_last) = gnu_next; \
7239 else \
7240 gnu_field_list = gnu_next; \
7241 \
7242 DECL_CHAIN (gnu_field) = (LIST); \
7243 (LIST) = gnu_field; \
7244 } while (0)
7247 {
7251 {
7254 }
7258 {
7261 }
7264 {
7267 }
7270 {
7280 }
7283 }
7285 #undef MOVE_FROM_FIELD_LIST_TO
7289 /* If permitted, we reorder the fields as follows:
7291 1) all fixed length fields,
7292 2) all fields whose length doesn't depend on discriminants,
7293 3) all fields whose length depends on discriminants,
7294 4) the variant part,
7296 within the record and within each variant recursively. */
7298 gnu_field_list
7301 /* Otherwise, if there is an aliased field placed after a field whose length
7302 depends on discriminants, we put all the fields of the latter sort, last.
7303 We need to do this in case an object of this record type is mutable. */
7307 /* If P_REP_LIST is nonzero, this means that we are asked to move the fields
7308 in our REP list to the previous level because this level needs them in
7309 order to do a correct layout, i.e. avoid having overlapping fields. */
7313 /* Otherwise, sort the fields by bit position and put them into their own
7314 record, before the others, if we also have fields without rep clause. */
7316 {
7321 /* If all the fields have a rep clause, we can do a flat layout. */
7322 layout_with_rep = !gnu_field_list
7324 gnu_rep_type
7328 gnu_field;
7334 /* Put the fields in the list in order of increasing position, which
7335 means we start from the end. */
7338 {
7342 }
7346 else
7347 {
7350 /* If FIRST_FREE_POS is nonzero, we need to ensure that the fields
7351 without rep clause are laid out starting from this position.
7352 Therefore, we force it as a minimal size on the REP part. */
7353 gnu_rep_part
7356 /* Chain the REP part at the beginning of the field list. */
7359 }
7360 }
7362 /* Chain the variant part at the end of the field list. */
7374 /* Chain the fields with zero size at the beginning of the field list. */
7380 }
7381 \f
7382 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
7383 placed into an Esize, Component_Bit_Offset, or Component_Size value
7384 in the GNAT tree. */
7386 static Uint
7388 {
7389 TCode tcode;
7394 /* See if we've already saved the value for this node. */
7396 {
7404 }
7405 else
7408 /* If we do not return inside this switch, TCODE will be set to the
7409 code to use for a Create_Node operand and LEN (set above) will be
7410 the number of recursive calls for us to make. */
7413 {
7418 /* The only case we handle here is a simple discriminant reference. */
7420 {
7423 /* Climb up the chain of successive extensions, if any. */
7430 return
7432 }
7439 /* Now just list the operations we handle. */
7470 /* For negative values in sizetype, build NEGATE_EXPR of the opposite.
7471 Such values appear in expressions with aligning patterns. Note that,
7472 since sizetype is unsigned, we have to jump through some hoops. */
7474 {
7478 {
7481 }
7482 }
7486 /* In regular mode, inline back only if symbolic annotation is requested
7487 in order to avoid memory explosion on big discriminated record types.
7488 But not in ASIS mode, as symbolic annotation is required for DDA. */
7490 {
7494 }
7495 else
7498 /* Fall through... */
7502 }
7504 /* Now get each of the operands that's relevant for this code. If any
7505 cannot be expressed as a repinfo node, say we can't. */
7510 {
7513 else
7517 }
7521 /* Save the result in the cache. */
7523 {
7525 /* We can't assume the hash table data hasn't moved since the initial
7526 look up, so we have to search again. Allocating and inserting an
7527 entry at that point would be an alternative, but then we'd better
7528 discard the entry if we decided not to cache it. */
7534 }
7537 }
7539 /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
7540 and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
7541 size and alignment used by Gigi. Prefer SIZE over TYPE_SIZE if non-null.
7542 BY_REF is true if the object is used by reference. */
7544 void
7546 {
7548 {
7551 else
7553 }
7556 {
7565 }
7570 }
7572 /* Return first element of field list whose TREE_PURPOSE is the same as ELEM.
7573 Return NULL_TREE if there is no such element in the list. */
7575 static tree
7577 {
7579 {
7584 }
7586 }
7588 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding GCC type,
7589 set Component_Bit_Offset and Esize of the components to the position and
7590 size used by Gigi. */
7592 static void
7594 {
7595 Entity_Id gnat_field;
7596 tree gnu_list;
7598 /* We operate by first making a list of all fields and their position (we
7599 can get the size easily) and then update all the sizes in the tree. */
7600 gnu_list
7610 {
7612 gnu_list);
7614 {
7615 tree parent_offset;
7617 /* If we are just annotating types and the type is tagged, the tag
7618 and the parent components are not generated by the front-end so
7619 we need to add the appropriate offset to each component without
7620 representation clause. */
7624 {
7625 /* For a component appearing in the current extension, the
7626 offset is the size of the parent. */
7629 parent_offset
7631 bitsizetype);
7632 else
7636 parent_offset
7639 }
7640 else
7643 Set_Component_Bit_Offset
7645 annotate_value
7649 parent_offset)));
7653 }
7655 {
7656 /* If there is no entry, this is an inherited component whose
7657 position is the same as in the parent type. */
7658 Set_Component_Bit_Offset
7664 }
7665 }
7666 }
7667 \f
7668 /* Scan all fields in GNU_TYPE and return a TREE_LIST where TREE_PURPOSE is
7669 the FIELD_DECL and TREE_VALUE a TREE_VEC containing the byte position, the
7670 value to be placed into DECL_OFFSET_ALIGN and the bit position. The list
7671 of fields is flattened, except for variant parts if DO_NOT_FLATTEN_VARIANT
7672 is set to true. GNU_POS is to be added to the position, GNU_BITPOS to the
7673 bit position, OFFSET_ALIGN is the present offset alignment. GNU_LIST is a
7674 pre-existing list to be chained to the newly created entries. */
7676 static tree
7679 {
7680 tree gnu_field;
7683 gnu_field;
7685 {
7690 unsigned int our_offset_align
7699 /* Recurse on internal fields, flattening the nested fields except for
7700 those in the variant part, if requested. */
7702 {
7706 gnu_list
7710 else
7711 gnu_list
7715 }
7716 }
7719 }
7721 /* Return a list describing the substitutions needed to reflect the
7722 discriminant substitutions from GNAT_TYPE to GNAT_SUBTYPE. They can
7723 be in any order. The values in an element of the list are in the form
7724 of operands to SUBSTITUTE_IN_EXPR. DEFINITION is true if this is for
7725 a definition of GNAT_SUBTYPE. */
7729 {
7731 Entity_Id gnat_discrim;
7732 Node_Id gnat_constr;
7739 /* Ignore access discriminants. */
7741 {
7744 elaborate_expression
7750 }
7753 }
7755 /* Scan all fields in QUAL_UNION_TYPE and return a list describing the
7756 variants of QUAL_UNION_TYPE that are still relevant after applying
7757 the substitutions described in SUBST_LIST. GNU_LIST is a pre-existing
7758 list to be prepended to the newly created entries. */
7763 {
7764 tree gnu_field;
7767 gnu_field;
7769 {
7777 /* If the new qualifier is not unconditionally false, its variant may
7778 still be accessed. */
7780 {
7786 /* Recurse on the variant subpart of the variant, if any. */
7792 /* If the new qualifier is unconditionally true, the subsequent
7793 variants cannot be accessed. */
7796 }
7797 }
7800 }
7801 \f
7802 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
7803 corresponding to GNAT_OBJECT. If the size is valid, return an INTEGER_CST
7804 corresponding to its value. Otherwise, return NULL_TREE. KIND is set to
7805 VAR_DECL if we are specifying the size of an object, TYPE_DECL for the
7806 size of a type, and FIELD_DECL for the size of a field. COMPONENT_P is
7807 true if we are being called to process the Component_Size of GNAT_OBJECT;
7808 this is used only for error messages. ZERO_OK is true if a size of zero
7809 is permitted; if ZERO_OK is false, it means that a size of zero should be
7810 treated as an unspecified size. */
7812 static tree
7815 {
7816 Node_Id gnat_error_node;
7819 /* Return 0 if no size was specified. */
7823 /* Ignore a negative size since that corresponds to our back-annotation. */
7827 /* Find the node to use for error messages. */
7834 else
7837 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
7838 but cannot be represented in bitsizetype. */
7841 {
7844 gnat_object);
7845 else
7847 gnat_object);
7849 }
7851 /* Ignore a zero size if it is not permitted. */
7855 /* The size of objects is always a multiple of a byte. */
7858 {
7862 else
7866 }
7868 /* If this is an integral type or a packed array type, the front-end has
7869 already verified the size, so we need not do it here (which would mean
7870 checking against the bounds). However, if this is an aliased object,
7871 it may not be smaller than the type of the object. */
7876 /* If the object is a record that contains a template, add the size of the
7877 template to the specified size. */
7883 /* If a type needs strict alignment, a component of this type in
7884 a packed record cannot be packed and thus uses the type size. */
7887 else
7890 /* Modify the size of a discriminated type to be the maximum size. */
7894 /* If this is an access type or a fat pointer, the minimum size is that given
7895 by the smallest integral mode that's valid for pointers. */
7897 {
7902 }
7904 /* Issue an error either if the default size of the object isn't a constant
7905 or if the new size is smaller than it. */
7909 {
7911 post_error_ne_tree
7914 else
7915 post_error_ne_tree
7919 }
7922 }
7923 \f
7924 /* Similarly, but both validate and process a value of RM size. This routine
7925 is only called for types. */
7927 static void
7929 {
7930 Node_Id gnat_attr_node;
7933 /* Do nothing if no size was specified. */
7937 /* Ignore a negative size since that corresponds to our back-annotation. */
7941 /* Only issue an error if a Value_Size clause was explicitly given.
7942 Otherwise, we'd be duplicating an error on the Size clause. */
7943 gnat_attr_node
7946 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
7947 but cannot be represented in bitsizetype. */
7950 {
7953 gnat_entity);
7955 }
7957 /* Ignore a zero size unless a Value_Size clause exists, or a size clause
7958 exists, or this is an integer type, in which case the front-end will
7959 have always set it. */
7968 /* If the old size is self-referential, get the maximum size. */
7972 /* Issue an error either if the old size of the object isn't a constant or
7973 if the new size is smaller than it. The front-end has already verified
7974 this for scalar and packed array types. */
7982 && TYPE_PACKED_ARRAY_TYPE_P
7985 {
7987 post_error_ne_tree
7991 }
7993 /* Otherwise, set the RM size proper for integral types... */
8000 /* ...or the Ada size for record and union types. */
8004 }
8005 \f
8006 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
8007 a type or object whose present alignment is ALIGN. If this alignment is
8008 valid, return it. Otherwise, give an error and return ALIGN. */
8010 static unsigned int
8012 {
8015 Node_Id gnat_error_node;
8017 /* Don't worry about checking alignment if alignment was not specified
8018 by the source program and we already posted an error for this entity. */
8022 /* Post the error on the alignment clause if any. Note, for the implicit
8023 base type of an array type, the alignment clause is on the first
8024 subtype. */
8032 gnat_error_node =
8035 else
8038 /* Within GCC, an alignment is an integer, so we must make sure a value is
8039 specified that fits in that range. Also, there is an upper bound to
8040 alignments we can support/allow. */
8048 {
8052 /* If the default alignment of "double" or larger scalar types is
8053 specifically capped and the new alignment is above the cap, do
8054 not post an error and change the alignment only if there is an
8055 alignment clause; this makes it possible to have the associated
8056 GCC type overaligned by default for performance reasons. */
8058 {
8059 Entity_Id gnat_type
8061 is_capped_double
8063 }
8065 {
8066 Entity_Id gnat_type
8068 is_capped_double
8070 }
8071 else
8075 {
8078 }
8079 else
8080 {
8087 }
8088 }
8089 else
8090 {
8094 }
8097 }
8098 \f
8099 /* Verify that TYPE is something we can implement atomically. If not, issue
8100 an error for GNAT_ENTITY. COMPONENT_P is true if we are being called to
8101 process a component type. */
8103 static void
8105 {
8107 Node_Id gnat_node;
8108 machine_mode mode;
8111 tree size;
8113 /* If this is an anonymous base type, nothing to check, the error will be
8114 reported on the source type if need be. */
8123 /* Consider all aligned floating-point types atomic and any aligned types
8124 that are represented by integers no wider than a machine word. */
8131 /* For the moment, also allow anything that has an alignment equal to its
8132 size and which is smaller than a word. */
8143 {
8144 unsigned char pragma_id
8149 {
8152 }
8153 }
8158 else
8161 }
8162 \f
8164 /* Helper for the intrin compatibility checks family. Evaluate whether
8165 two types are definitely incompatible. */
8167 static bool
8169 {
8184 {
8191 /* Assume designated types are ok. We'd need to account for char * and
8192 void * variants to do better, which could rapidly get messy and isn't
8193 clearly worth the effort. */
8198 }
8201 }
8203 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8204 on the Ada/builtin argument lists for the INB binding. */
8206 static bool
8208 {
8214 /* Sequence position of the last argument we checked. */
8218 {
8222 /* If we've exhausted both lists simultaneously, we're done. */
8226 /* If one list is shorter than the other, they fail to match. */
8230 /* If we're done with the Ada args and not with the internal builtin
8231 args, or the other way around, complain. */
8234 {
8237 }
8241 {
8245 }
8247 /* Otherwise, check that types match for the current argument. */
8248 argpos ++;
8250 {
8254 }
8259 }
8262 }
8264 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8265 on the Ada/builtin return values for the INB binding. */
8267 static bool
8269 {
8273 /* Accept function imported as procedure, common and convenient. */
8278 /* If return type is Address (integer type), map it to void *. */
8282 /* Check return types compatibility otherwise. Note that this
8283 handles void/void as well. */
8285 {
8289 }
8292 }
8294 /* Check and return whether the Ada and gcc builtin profiles bound by INB are
8295 compatible. Issue relevant warnings when they are not.
8297 This is intended as a light check to diagnose the most obvious cases, not
8298 as a full fledged type compatibility predicate. It is the programmer's
8299 responsibility to ensure correctness of the Ada declarations in Imports,
8300 especially when binding straight to a compiler internal. */
8302 static bool
8304 {
8305 /* Check compatibility on return values and argument lists, each responsible
8306 for posting warnings as appropriate. Ensure use of the proper sloc for
8307 this purpose. */
8320 }
8321 \f
8322 /* Return a FIELD_DECL node modeled on OLD_FIELD. FIELD_TYPE is its type
8323 and RECORD_TYPE is the type of the parent. If SIZE is nonzero, it is the
8324 specified size for this field. POS_LIST is a position list describing
8325 the layout of OLD_FIELD and SUBST_LIST a substitution list to be applied
8326 to this layout. */
8328 static tree
8332 {
8344 /* If the position is now a constant, we can set it as the position of the
8345 field when we make it. Otherwise, we need to deal with it specially. */
8348 else
8351 new_field
8357 {
8359 /* Finalize the position. */
8368 }
8376 }
8378 /* Create the REP part of RECORD_TYPE with REP_TYPE. If MIN_SIZE is nonzero,
8379 it is the minimal size the REP_PART must have. */
8381 static tree
8383 {
8384 tree field;
8394 }
8396 /* Return the REP part of RECORD_TYPE, if any. Otherwise return NULL. */
8398 static tree
8400 {
8403 /* The REP part is the first field, internal, another record, and its name
8404 starts with an 'R'. */
8412 }
8414 /* Return the variant part of RECORD_TYPE, if any. Otherwise return NULL. */
8416 tree
8418 {
8419 tree field;
8421 /* The variant part is the only internal field that is a qualified union. */
8428 }
8430 /* Return a new variant part modeled on OLD_VARIANT_PART. VARIANT_LIST is
8431 the list of variants to be used and RECORD_TYPE is the type of the parent.
8432 POS_LIST is a position list describing the layout of fields present in
8433 OLD_VARIANT_PART and SUBST_LIST a substitution list to be applied to this
8434 layout. */
8436 static tree
8441 {
8449 /* First create the type of the variant part from that of the old one. */
8455 /* If the position of the variant part is constant, subtract it from the
8456 size of the type of the parent to get the new size. This manual CSE
8457 reduces the code size when not optimizing. */
8459 {
8469 first_bit));
8472 }
8473 else
8476 /* Now finish up the new variants and populate the union type. */
8478 {
8482 /* Skip variants that don't belong to this nesting level. */
8486 /* Retrieve the list of fields already added to the new variant. */
8490 /* If the old variant had a variant subpart, we need to create a new
8491 variant subpart and add it to the field list. */
8495 {
8496 tree new_variant_subpart
8501 }
8503 /* Finish up the new variant and create the field. No need for debug
8504 info thanks to the XVS type. */
8508 Empty);
8510 new_field
8518 }
8520 /* Finish up the union type and create the variant part. No need for debug
8521 info thanks to the XVS type. Note that we don't reverse the field list
8522 because VARIANT_LIST has been traversed in reverse order. */
8526 Empty);
8528 new_variant_part
8534 /* With multiple discriminants it is possible for an inner variant to be
8535 statically selected while outer ones are not; in this case, the list
8536 of fields of the inner variant is not flattened and we end up with a
8537 qualified union with a single member. Drop the useless container. */
8539 {
8548 }
8551 }
8553 /* Copy the size (and alignment and alias set) from OLD_TYPE to NEW_TYPE,
8554 which are both RECORD_TYPE, after applying the substitutions described
8555 in SUBST_LIST. */
8557 static void
8560 {
8584 SET_TYPE_ADA_SIZE
8588 /* Finalize the size. */
8591 }
8593 /* Add a parallel type to GNU_TYPE, the translation of GNAT_ENTITY, which is
8594 the implementation type of a packed array type (Is_Packed_Array_Impl_Type).
8595 The parallel type is the original array type if it has been translated. */
8597 static void
8599 {
8600 Entity_Id gnat_original_array_type
8602 tree gnu_original_array_type;
8613 }
8614 \f
8615 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a
8616 type with all size expressions that contain F in a PLACEHOLDER_EXPR
8617 updated by replacing F with R.
8619 The function doesn't update the layout of the type, i.e. it assumes
8620 that the substitution is purely formal. That's why the replacement
8621 value R must itself contain a PLACEHOLDER_EXPR. */
8623 tree
8625 {
8626 tree nt;
8631 {
8637 /* First the domain types of arrays. */
8640 {
8652 SET_TYPE_INDEX_TYPE
8656 }
8658 /* Then the subtypes. */
8661 {
8673 }
8685 /* These should never show up here. */
8689 {
8706 }
8711 {
8713 tree field;
8715 /* Start out with no fields, make new fields, and chain them
8716 in. If we haven't actually changed the type of any field,
8717 discard everything we've done and return the old type. */
8722 {
8727 {
8730 }
8734 {
8737 }
8739 /* Do the substitution inside the qualifier, if any. */
8741 {
8744 {
8747 }
8748 }
8755 }
8765 }
8769 }
8770 }
8771 \f
8772 /* Return the RM size of GNU_TYPE. This is the actual number of bits
8773 needed to represent the object. */
8775 tree
8777 {
8778 /* For integral types, we store the RM size explicitly. */
8782 /* Return the RM size of the actual data plus the size of the template. */
8785 return
8790 /* For record or union types, we store the size explicitly. */
8796 /* For other types, this is just the size. */
8798 }
8799 \f
8800 /* Return the name to be used for GNAT_ENTITY. If a type, create a
8801 fully-qualified name, possibly with type information encoding.
8802 Otherwise, return the name. */
8804 tree
8806 {
8809 }
8811 /* Return an identifier representing the external name to be used for
8812 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
8813 and the specified suffix. */
8815 tree
8817 {
8825 /* A variable using the Stdcall convention lives in a DLL. We adjust
8826 its name to use the jump table, the _imp__NAME contains the address
8827 for the NAME variable. */
8830 {
8836 }
8839 }
8841 /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
8842 string, return a new IDENTIFIER_NODE that is the concatenation of
8843 the name followed by "___" and the specified suffix. */
8845 tree
8847 {
8854 }
8856 /* Initialize data structures of the decl.c module. */
8858 void
8860 {
8861 /* Initialize the cache of annotated values. */
8863 }
8865 /* Destroy data structures of the decl.c module. */
8867 void
8869 {
8870 /* Destroy the cache of annotated values. */
8873 }