| blob | 1719d1cae5adfb83cee12bc092b570faced44cc7 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2010, 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 ****************************************************************************/
53 /* Convention_Stdcall should be processed in a specific way on Windows targets
54 only. The macro below is a helper to avoid having to check for a Windows
55 specific attribute throughout this unit. */
57 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
58 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
59 #else
60 #define Has_Stdcall_Convention(E) (0)
61 #endif
63 /* Stack realignment is necessary for functions with foreign conventions when
64 the ABI doesn't mandate as much as what the compiler assumes - that is, up
65 to PREFERRED_STACK_BOUNDARY.
67 Such realignment can be requested with a dedicated function type attribute
68 on the targets that support it. We define FOREIGN_FORCE_REALIGN_STACK to
69 characterize the situations where the attribute should be set. We rely on
70 compiler configuration settings for 'main' to decide. */
72 #ifdef MAIN_STACK_BOUNDARY
73 #define FOREIGN_FORCE_REALIGN_STACK \
74 (MAIN_STACK_BOUNDARY < PREFERRED_STACK_BOUNDARY)
75 #else
76 #define FOREIGN_FORCE_REALIGN_STACK 0
77 #endif
79 struct incomplete
80 {
82 tree old_type;
83 Entity_Id full_type;
84 };
86 /* These variables are used to defer recursively expanding incomplete types
87 while we are processing an array, a record or a subprogram type. */
91 /* This variable is used to delay expanding From_With_Type types until the
92 end of the spec. */
95 /* These variables are used to defer finalizing types. The element of the
96 list is the TYPE_DECL associated with the type. */
101 tree discriminant;
102 tree replacement;
109 /* The type of the variant. */
110 tree type;
112 /* The associated field. */
113 tree field;
115 /* The value of the qualifier. */
116 tree qual;
118 /* The record associated with this variant. */
119 tree record;
125 /* A hash table used to cache the result of annotate_value. */
129 enum alias_set_op
130 {
131 ALIAS_SET_COPY,
132 ALIAS_SET_SUBSET,
133 ALIAS_SET_SUPERSET
134 };
181 /* The relevant constituents of a subprogram binding to a GCC builtin. Used
182 to pass around calls performing profile compatibilty checks. */
192 \f
193 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
194 entity, return the equivalent GCC tree for that entity (a ..._DECL node)
195 and associate the ..._DECL node with the input GNAT defining identifier.
197 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
198 initial value (in GCC tree form). This is optional for a variable. For
199 a renamed entity, GNU_EXPR gives the object being renamed.
201 DEFINITION is nonzero if this call is intended for a definition. This is
202 used for separate compilation where it is necessary to know whether an
203 external declaration or a definition must be created if the GCC equivalent
204 was not created previously. The value of 1 is normally used for a nonzero
205 DEFINITION, but a value of 2 is used in special circumstances, defined in
206 the code. */
208 tree
210 {
211 /* Contains the kind of the input GNAT node. */
213 /* True if this is a type. */
215 /* True if debug info is requested for this entity. */
217 /* True if this entity is to be considered as imported. */
218 const bool imported_p
220 /* For a type, contains the equivalent GNAT node to be used in gigi. */
222 /* Temporary used to walk the GNAT tree. */
223 Entity_Id gnat_temp;
224 /* Contains the GCC DECL node which is equivalent to the input GNAT node.
225 This node will be associated with the GNAT node by calling at the end
226 of the `switch' statement. */
228 /* Contains the GCC type to be used for the GCC node. */
230 /* Contains the GCC size tree to be used for the GCC node. */
232 /* Contains the GCC name to be used for the GCC node. */
233 tree gnu_entity_name;
234 /* True if we have already saved gnu_decl as a GNAT association. */
236 /* True if we incremented defer_incomplete_level. */
238 /* True if we incremented force_global. */
240 /* True if we should check to see if elaborated during processing. */
242 /* True if we made GNU_DECL and its type here. */
244 /* Size and alignment of the GCC node, if meaningful. */
246 /* Contains the list of attributes directly attached to the entity. */
249 /* Since a use of an Itype is a definition, process it as such if it
250 is not in a with'ed unit. */
252 && is_type
256 {
257 /* Ensure that we are in a subprogram mentioned in the Scope chain of
258 this entity, our current scope is global, or we encountered a task
259 or entry (where we can't currently accurately check scoping). */
262 {
265 }
270 {
275 gnat_temp
287 && (current_function_decl
289 {
292 }
293 }
295 /* This abort means the Itype has an incorrect scope, i.e. that its
296 scope does not correspond to the subprogram it is declared in. */
298 }
300 /* If we've already processed this entity, return what we got last time.
301 If we are defining the node, we should not have already processed it.
302 In that case, we will abort below when we try to save a new GCC tree
303 for this object. We also need to handle the case of getting a dummy
304 type when a Full_View exists. */
307 {
314 {
315 gnu_decl
319 }
322 }
324 /* If this is a numeric or enumeral type, or an access type, a nonzero
325 Esize must be specified unless it was specified by the programmer. */
335 /* The RM size must be specified for all discrete and fixed-point types. */
339 /* If we get here, it means we have not yet done anything with this entity.
340 If we are not defining it, it must be a type or an entity that is defined
341 elsewhere or externally, otherwise we should have defined it already. */
343 || type_annotate_only
344 || is_type
351 /* Get the name of the entity and set up the line number and filename of
352 the original definition for use in any decl we make. */
356 /* For cases when we are not defining (i.e., we are referencing from
357 another compilation unit) public entities, show we are at global level
358 for the purpose of computing scopes. Don't do this for components or
359 discriminants since the relevant test is whether or not the record is
360 being defined. Don't do this for constants either as we'll look into
361 their defining expression in the local context. */
370 /* Handle any attributes directly attached to the entity. */
374 /* Do some common processing for types. */
376 {
377 /* Compute the equivalent type to be used in gigi. */
380 /* Machine_Attributes on types are expected to be propagated to
381 subtypes. The corresponding Gigi_Rep_Items are only attached
382 to the first subtype though, so we handle the propagation here. */
389 /* Compute a default value for the size of the type. */
392 {
400 else
405 }
406 else
408 }
411 {
413 /* If this is a use of a deferred constant without address clause,
414 get its full definition. */
418 {
419 gnu_decl
423 }
425 /* If we have an external constant that we are not defining, get the
426 expression that is was defined to represent. We may throw it away
427 later if it is not a constant. But do not retrieve the expression
428 if it is an allocator because the designated type might be dummy
429 at this point. */
435 {
438 /* The expression may contain N_Expression_With_Actions nodes and
439 thus object declarations from other units. In this case, even
440 though the expression will eventually be discarded since not a
441 constant, the declarations would be stuck either in the global
442 varpool or in the current scope. Therefore we force the local
443 context and create a fake scope that we'll zap at the end. */
445 {
448 }
456 }
458 /* Ignore deferred constant definitions without address clause since
459 they are processed fully in the front-end. If No_Initialization
460 is set, this is not a deferred constant but a constant whose value
461 is built manually. And constants that are renamings are handled
462 like variables. */
464 && !gnu_expr
468 {
472 }
474 /* Ignore constant definitions already marked with the error node. See
475 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
477 && gnu_expr
480 {
483 }
488 /* We used to special case VMS exceptions here to directly map them to
489 their associated condition code. Since this code had to be masked
490 dynamically to strip off the severity bits, this caused trouble in
491 the GCC/ZCX case because the "type" pointers we store in the tables
492 have to be static. We now don't special case here anymore, and let
493 the regular processing take place, which leaves us with a regular
494 exception data object for VMS exceptions too. The condition code
495 mapping is taken care of by the front end and the bitmasking by the
496 run-time library. */
501 {
502 /* The GNAT record where the component was defined. */
505 /* If the variable is an inherited record component (in the case of
506 extended record types), just return the inherited entity, which
507 must be a FIELD_DECL. Likewise for discriminants.
508 For discriminants of untagged records which have explicit
509 stored discriminants, return the entity for the corresponding
510 stored discriminant. Also use Original_Record_Component
511 if the record has a private extension. */
514 {
515 gnu_decl
520 }
522 /* If the enclosing record has explicit stored discriminants,
523 then it is an untagged record. If the Corresponding_Discriminant
524 is not empty then this must be a renamed discriminant and its
525 Original_Record_Component must point to the corresponding explicit
526 stored discriminant (i.e. we should have taken the previous
527 branch). */
530 {
531 /* A tagged record has no explicit stored discriminants. */
534 gnu_decl
539 }
543 {
548 }
550 /* If the enclosing record has explicit stored discriminants, then
551 it is an untagged record. If the Corresponding_Discriminant
552 is not empty then this must be a renamed discriminant and its
553 Original_Record_Component must point to the corresponding explicit
554 stored discriminant (i.e. we should have taken the first
555 branch). */
561 /* Otherwise, if we are not defining this and we have no GCC type
562 for the containing record, make one for it. Then we should
563 have made our own equivalent. */
565 {
566 /* ??? If this is in a record whose scope is a protected
567 type and we have an Original_Record_Component, use it.
568 This is a workaround for major problems in protected type
569 handling. */
576 {
577 gnu_decl
583 }
589 }
591 else
592 /* Here we have no GCC type and this is a reference rather than a
593 definition. This should never happen. Most likely the cause is
594 reference before declaration in the gnat tree for gnat_entity. */
596 }
602 /* Simple variables, loop variables, Out parameters and exceptions. */
603 object:
604 {
605 bool const_flag
620 tree gnu_object_size;
623 {
627 else
629 }
631 /* Get the type after elaborating the renamed object. */
634 /* If this is a standard exception definition, then use the standard
635 exception type. This is necessary to make sure that imported and
636 exported views of exceptions are properly merged in LTO mode. */
641 /* For a debug renaming declaration, build a debug-only entity. */
643 {
644 /* Force a non-null value to make sure the symbol is retained. */
648 integer_minus_one_node));
655 }
657 /* If this is a loop variable, its type should be the base type.
658 This is because the code for processing a loop determines whether
659 a normal loop end test can be done by comparing the bounds of the
660 loop against those of the base type, which is presumed to be the
661 size used for computation. But this is not correct when the size
662 of the subtype is smaller than the type. */
666 /* Reject non-renamed objects whose type is an unconstrained array or
667 any object whose type is a dummy type or void. */
672 {
675 force_global--;
677 }
679 /* If an alignment is specified, use it if valid. Note that exceptions
680 are objects but don't have an alignment. We must do this before we
681 validate the size, since the alignment can affect the size. */
683 {
688 /* No point in changing the type if there is an address clause
689 as the final type of the object will be a reference type. */
692 else
693 gnu_type
696 }
698 /* If we are defining the object, see if it has a Size and validate it
699 if so. If we are not defining the object and a Size clause applies,
700 simply retrieve the value. We don't want to ignore the clause and
701 it is expected to have been validated already. Then get the new
702 type, if any. */
711 {
712 gnu_type
718 }
720 /* If this object has self-referential size, it must be a record with
721 a default discriminant. We are supposed to allocate an object of
722 the maximum size in this case, unless it is a constant with an
723 initializing expression, in which case we can get the size from
724 that. Note that the resulting size may still be a variable, so
725 this may end up with an indirect allocation. */
728 {
730 {
733 {
734 /* If the initializing expression is itself a constant,
735 despite having a nominal type with self-referential
736 size, we can get the size directly from it. */
738 && TYPE_IS_PADDING_P
742 || DECL_READONLY_ONCE_ELAB
745 else
746 gnu_size
748 }
749 else
751 }
752 /* We may have no GNU_EXPR because No_Initialization is
753 set even though there's an Expression. */
758 gnu_size
760 (Etype
762 else
763 {
766 }
767 }
769 /* If the size is zero byte, make it one byte since some linkers have
770 troubles with zero-sized objects. If the object will have a
771 template, that will make it nonzero so don't bother. Also avoid
772 doing that for an object renaming or an object with an address
773 clause, as we would lose useful information on the view size
774 (e.g. for null array slices) and we are not allocating the object
775 here anyway. */
788 /* If this is an object with no specified size and alignment, and
789 if either it is atomic or we are not optimizing alignment for
790 space and it is composite and not an exception, an Out parameter
791 or a reference to another object, and the size of its type is a
792 constant, set the alignment to the smallest one which is not
793 smaller than the size, with an appropriate cap. */
802 && !imported_p
806 {
807 /* No point in jumping through all the hoops needed in order
808 to support BIGGEST_ALIGNMENT if we don't really have to.
809 So we cap to the smallest alignment that corresponds to
810 a known efficient memory access pattern of the target. */
812 ? BIGGEST_ALIGNMENT
818 else
821 /* But make sure not to under-align the object. */
825 /* And honor the minimum valid atomic alignment, if any. */
826 #ifdef MINIMUM_ATOMIC_ALIGNMENT
829 #endif
830 }
832 /* If the object is set to have atomic components, find the component
833 type and validate it.
835 ??? Note that we ignore Has_Volatile_Components on objects; it's
836 not at all clear what to do in that case. */
838 {
847 }
849 /* Now check if the type of the object allows atomic access. Note
850 that we must test the type, even if this object has size and
851 alignment to allow such access, because we will be going inside
852 the padded record to assign to the object. We could fix this by
853 always copying via an intermediate value, but it's not clear it's
854 worth the effort. */
858 /* If this is an aliased object with an unconstrained nominal subtype,
859 make a type that includes the template. */
863 {
864 tree gnu_fat
867 gnu_type
871 debug_info_p);
872 }
874 #ifdef MINIMUM_ATOMIC_ALIGNMENT
875 /* If the size is a constant and no alignment is specified, force
876 the alignment to be the minimum valid atomic alignment. The
877 restriction on constant size avoids problems with variable-size
878 temporaries; if the size is variable, there's no issue with
879 atomic access. Also don't do this for a constant, since it isn't
880 necessary and can interfere with constant replacement. Finally,
881 do not do it for Out parameters since that creates an
882 size inconsistency with In parameters. */
891 #endif
893 /* Make a new type with the desired size and alignment, if needed.
894 But do not take into account alignment promotions to compute the
895 size of the object. */
902 /* If this is a renaming, avoid as much as possible to create a new
903 object. However, in several cases, creating it is required.
904 This processing needs to be applied to the raw expression so
905 as to make it more likely to rename the underlying object. */
907 {
910 /* If the renamed object had padding, strip off the reference
911 to the inner object and reset our type. */
914 /* Strip useless conversions around the object. */
916 && gnat_types_compatible_p
919 {
922 }
924 /* Case 1: If this is a constant renaming stemming from a function
925 call, treat it as a normal object whose initial value is what
926 is being renamed. RM 3.3 says that the result of evaluating a
927 function call is a constant object. As a consequence, it can
928 be the inner object of a constant renaming. In this case, the
929 renaming must be fully instantiated, i.e. it cannot be a mere
930 reference to (part of) an existing object. */
932 {
938 }
940 /* Otherwise, see if we can proceed with a stabilized version of
941 the renamed entity or if we need to make a new object. */
943 {
947 /* Case 2: If the renaming entity need not be materialized and
948 the renamed expression is something we can stabilize, use
949 that for the renaming. At the global level, we can only do
950 this if we know no SAVE_EXPRs need be made, because the
951 expression we return might be used in arbitrary conditional
952 branches so we must force the evaluation of the SAVE_EXPRs
953 immediately and this requires a proper function context.
954 Note that an external constant is at the global level. */
960 {
961 maybe_stable_expr
965 {
966 /* ??? No DECL_EXPR is created so we need to mark
967 the expression manually lest it is shared. */
977 }
979 /* The stabilization failed. Keep maybe_stable_expr
980 untouched here to let the pointer case below know
981 about that failure. */
982 }
984 /* Case 3: If this is a constant renaming and creating a
985 new object is allowed and cheap, treat it as a normal
986 object whose initial value is what is being renamed. */
988 && !Is_Composite_Type
990 ;
992 /* Case 4: Make this into a constant pointer to the object we
993 are to rename and attach the object to the pointer if it is
994 something we can stabilize.
996 From the proper scope, attached objects will be referenced
997 directly instead of indirectly via the pointer to avoid
998 subtle aliasing problems with non-addressable entities.
999 They have to be stable because we must not evaluate the
1000 variables in the expression every time the renaming is used.
1001 The pointer is called a "renaming" pointer in this case.
1003 In the rare cases where we cannot stabilize the renamed
1004 object, we just make a "bare" pointer, and the renamed
1005 entity is always accessed indirectly through it. */
1006 else
1007 {
1012 /* If the previous attempt at stabilizing failed, there
1013 is no point in trying again and we reuse the result
1014 without attaching it to the pointer. In this case it
1015 will only be used as the initializing expression of
1016 the pointer and thus needs no special treatment with
1017 regard to multiple evaluations. */
1019 ;
1021 /* Otherwise, try to stabilize and attach the expression
1022 to the pointer if the stabilization succeeds.
1024 Note that this might introduce SAVE_EXPRs and we don't
1025 check whether we're at the global level or not. This
1026 is fine since we are building a pointer initializer and
1027 neither the pointer nor the initializing expression can
1028 be accessed before the pointer elaboration has taken
1029 place in a correct program.
1031 These SAVE_EXPRs will be evaluated at the right place
1032 by either the evaluation of the initializer for the
1033 non-global case or the elaboration code for the global
1034 case, and will be attached to the elaboration procedure
1035 in the latter case. */
1036 else
1037 {
1038 maybe_stable_expr
1044 /* Attaching is actually performed downstream, as soon
1045 as we have a VAR_DECL for the pointer we make. */
1046 }
1049 maybe_stable_expr);
1053 }
1054 }
1055 }
1057 /* Make a volatile version of this object's type if we are to make
1058 the object volatile. We also interpret 13.3(19) conservatively
1059 and disallow any optimizations for such a non-constant object. */
1061 || (!const_flag
1064 || imported_p
1071 /* If we are defining an aliased object whose nominal subtype is
1072 unconstrained, the object is a record that contains both the
1073 template and the object. If there is an initializer, it will
1074 have already been converted to the right type, but we need to
1075 create the template if there is no initializer. */
1077 && !gnu_expr
1080 /* Beware that padding might have been introduced above. */
1083 == RECORD_TYPE
1084 && TYPE_CONTAINS_TEMPLATE_P
1086 {
1087 tree template_field
1094 NULL_TREE);
1097 }
1099 /* Convert the expression to the type of the object except in the
1100 case where the object's type is unconstrained or the object's type
1101 is a padded record whose field is of self-referential size. In
1102 the former case, converting will generate unnecessary evaluations
1103 of the CONSTRUCTOR to compute the size and in the latter case, we
1104 want to only copy the actual data. */
1109 && CONTAINS_PLACEHOLDER_P
1113 /* If this is a pointer that doesn't have an initializing expression,
1114 initialize it to NULL, unless the object is imported. */
1117 && !gnu_expr
1121 /* If we are defining the object and it has an Address clause, we must
1122 either get the address expression from the saved GCC tree for the
1123 object if it has a Freeze node, or elaborate the address expression
1124 here since the front-end has guaranteed that the elaboration has no
1125 effects in this case. */
1127 {
1129 tree gnu_address
1135 /* Ignore the size. It's either meaningless or was handled
1136 above. */
1138 /* Convert the type of the object to a reference type that can
1139 alias everything as per 13.3(19). */
1140 gnu_type
1144 const_flag
1148 /* If this is a deferred constant, the initializer is attached to
1149 the full view. */
1151 gnu_expr
1152 = gnat_to_gnu
1155 /* If we don't have an initializing expression for the underlying
1156 variable, the initializing expression for the pointer is the
1157 specified address. Otherwise, we have to make a COMPOUND_EXPR
1158 to assign both the address and the initial value. */
1161 else
1162 gnu_expr
1164 build_binary_op
1167 gnu_address),
1168 gnu_expr),
1169 gnu_address);
1170 }
1172 /* If it has an address clause and we are not defining it, mark it
1173 as an indirect object. Likewise for Stdcall objects that are
1174 imported. */
1178 {
1179 /* Convert the type of the object to a reference type that can
1180 alias everything as per 13.3(19). */
1181 gnu_type
1185 /* No point in taking the address of an initializing expression
1186 that isn't going to be used. */
1189 /* If it has an address clause whose value is known at compile
1190 time, make the object a CONST_DECL. This will avoid a
1191 useless dereference. */
1193 {
1194 Node_Id gnat_address
1198 {
1201 }
1202 }
1205 }
1207 /* If we are at top level and this object is of variable size,
1208 make the actual type a hidden pointer to the real type and
1209 make the initializer be a memory allocation and initialization.
1210 Likewise for objects we aren't defining (presumed to be
1211 external references from other packages), but there we do
1212 not set up an initialization.
1214 If the object's size overflows, make an allocator too, so that
1215 Storage_Error gets raised. Note that we will never free
1216 such memory, so we presume it never will get allocated. */
1219 || !definition
1223 || !definition
1225 {
1230 /* In case this was a aliased object whose nominal subtype is
1231 unconstrained, the pointer above will be a thin pointer and
1232 build_allocator will automatically make the template.
1234 If we have a template initializer only (that we made above),
1235 pretend there is none and rely on what build_allocator creates
1236 again anyway. Otherwise (if we have a full initializer), get
1237 the data part and feed that to build_allocator.
1239 If we are elaborating a mutable object, tell build_allocator to
1240 ignore a possibly simpler size from the initializer, if any, as
1241 we must allocate the maximum possible size in this case. */
1243 {
1248 {
1249 gnu_alloc_type
1256 else
1257 gnu_expr
1258 = build_component_ref
1262 }
1267 gnat_entity);
1269 gnu_expr
1273 }
1274 else
1275 {
1278 }
1279 }
1281 /* If this object would go into the stack and has an alignment larger
1282 than the largest stack alignment the back-end can honor, resort to
1283 a variable of "aligning type". */
1286 {
1287 /* Create the new variable. No need for extra room before the
1288 aligned field as this is in automatic storage. */
1289 tree gnu_new_type
1293 tree gnu_new_var
1298 /* Initialize the aligned field if we have an initializer. */
1300 add_stmt_with_node
1302 build_component_ref
1305 gnu_expr),
1306 gnat_entity);
1308 /* And setup this entity as a reference to the aligned field. */
1310 gnu_expr
1311 = build_unary_op
1319 }
1325 /* Convert the expression to the type of the object except in the
1326 case where the object's type is unconstrained or the object's type
1327 is a padded record whose field is of self-referential size. In
1328 the former case, converting will generate unnecessary evaluations
1329 of the CONSTRUCTOR to compute the size and in the latter case, we
1330 want to only copy the actual data. */
1335 && CONTAINS_PLACEHOLDER_P
1339 /* If this name is external or there was a name specified, use it,
1340 unless this is a VMS exception object since this would conflict
1341 with the symbol we need to export in addition. Don't use the
1342 Interface_Name if there is an address clause (see CD30005). */
1351 /* If this is an aggregate constant initialized to a constant, force it
1352 to be statically allocated. This saves an initialization copy. */
1354 && const_flag
1363 /* Now create the variable or the constant and set various flags. */
1364 gnu_decl
1368 gnat_entity);
1372 /* If we are defining an Out parameter and optimization isn't enabled,
1373 create a fake PARM_DECL for debugging purposes and make it point to
1374 the VAR_DECL. Suppress debug info for the latter but make sure it
1375 will live on the stack so that it can be accessed from within the
1376 debugger through the PARM_DECL. */
1378 {
1385 }
1387 /* If this is a renaming pointer, attach the renamed object to it and
1388 register it if we are at the global level. Note that an external
1389 constant is at the global level. */
1391 {
1394 {
1397 }
1398 }
1400 /* If this is a constant and we are defining it or it generates a real
1401 symbol at the object level and we are referencing it, we may want
1402 or need to have a true variable to represent it:
1403 - if optimization isn't enabled, for debugging purposes,
1404 - if the constant is public and not overlaid on something else,
1405 - if its address is taken,
1406 - if either itself or its type is aliased. */
1415 {
1416 tree gnu_corr_var
1420 gnat_entity);
1424 /* As debugging information will be generated for the variable,
1425 do not generate debugging information for the constant. */
1428 else
1430 }
1432 /* If this is a constant, even if we don't need a true variable, we
1433 may need to avoid returning the initializer in every case. That
1434 can happen for the address of a (constant) constructor because,
1435 upon dereferencing it, the constructor will be reinjected in the
1436 tree, which may not be valid in every case; see lvalue_required_p
1437 for more details. */
1441 /* If this object is declared in a block that contains a block with an
1442 exception handler, and we aren't using the GCC exception mechanism,
1443 we must force this variable in memory in order to avoid an invalid
1444 optimization. */
1449 /* If we are defining an object with variable size or an object with
1450 fixed size that will be dynamically allocated, and we are using the
1451 setjmp/longjmp exception mechanism, update the setjmp buffer. */
1464 gnat_entity);
1466 /* Back-annotate Esize and Alignment of the object if not already
1467 known. Note that we pick the values of the type, not those of
1468 the object, to shield ourselves from low-level platform-dependent
1469 adjustments like alignment promotion. This is both consistent with
1470 all the treatment above, where alignment and size are set on the
1471 type of the object and not on the object directly, and makes it
1472 possible to support all confirming representation clauses. */
1475 }
1479 /* Return a TYPE_DECL for "void" that we previously made. */
1484 /* A special case: for the types Character and Wide_Character in
1485 Standard, we do not list all the literals. So if the literals
1486 are not specified, make this an unsigned type. */
1488 {
1492 /* Set TYPE_STRING_FLAG for Character and Wide_Character types.
1493 This is needed by the DWARF-2 back-end to distinguish between
1494 unsigned integer types and character types. */
1497 }
1499 {
1500 /* We have a list of enumeral constants in First_Literal. We make a
1501 CONST_DECL for each one and build into GNU_LITERAL_LIST the list to
1502 be placed into TYPE_FIELDS. Each node in the list is a TREE_LIST
1503 whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
1504 value of the literal. But when we have a regular boolean type, we
1505 simplify this a little by using a BOOLEAN_TYPE. */
1509 Entity_Id gnat_literal;
1513 else
1521 {
1522 tree gnu_value
1524 tree gnu_literal
1528 /* Do not generate debug info for individual enumerators. */
1533 }
1538 /* Note that the bounds are updated at the end of this function
1539 to avoid an infinite recursion since they refer to the type. */
1540 }
1546 /* For integer types, just make a signed type the appropriate number
1547 of bits. */
1552 {
1553 /* For modular types, make the unsigned type of the proper number
1554 of bits and then set up the modulus, if required. */
1557 /* Packed array types are supposed to be subtypes only. */
1562 /* Get the modulus in this type. If it overflows, assume it is because
1563 it is equal to 2**Esize. Note that there is no overflow checking
1564 done on unsigned type, so we detect the overflow by looking for
1565 a modulus of zero, which is otherwise invalid. */
1569 {
1574 }
1576 /* If the upper bound is not maximal, make an extra subtype. */
1579 {
1586 }
1587 }
1596 /* For integral subtypes, we make a new INTEGER_TYPE. Note that we do
1597 not want to call create_range_type since we would like each subtype
1598 node to be distinct. ??? Historically this was in preparation for
1599 when memory aliasing is implemented, but that's obsolete now given
1600 the call to relate_alias_sets below.
1602 The TREE_TYPE field of the INTEGER_TYPE points to the base type;
1603 this fact is used by the arithmetic conversion functions.
1605 We elaborate the Ancestor_Subtype if it is not in the current unit
1606 and one of our bounds is non-static. We do this to ensure consistent
1607 naming in the case where several subtypes share the same bounds, by
1608 elaborating the first such subtype first, thus using its name. */
1617 /* Set the precision to the Esize except for bit-packed arrays. */
1622 /* This should be an unsigned type if the base type is unsigned or
1623 if the lower bound is constant and non-negative or if the type
1624 is biased. */
1629 else
1633 SET_TYPE_RM_MIN_VALUE
1641 SET_TYPE_RM_MAX_VALUE
1649 /* One of the above calls might have caused us to be elaborated,
1650 so don't blow up if so. */
1652 {
1655 }
1660 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
1664 /* Inherit our alias set from what we're a subtype of. Subtypes
1665 are not different types and a pointer can designate any instance
1666 within a subtype hierarchy. */
1669 /* For a packed array, make the original array type a parallel type. */
1674 gnat_to_gnu_type
1677 discrete_type:
1679 /* We have to handle clauses that under-align the type specially. */
1682 && Present
1685 {
1689 }
1691 /* If the type we are dealing with represents a bit-packed array,
1692 we need to have the bits left justified on big-endian targets
1693 and right justified on little-endian targets. We also need to
1694 ensure that when the value is read (e.g. for comparison of two
1695 such values), we only get the good bits, since the unused bits
1696 are uninitialized. Both goals are accomplished by wrapping up
1697 the modular type in an enclosing record type. */
1700 {
1703 /* Set the RM size before wrapping up the original type. */
1708 /* Create a stripped-down declaration, mainly for debugging. */
1712 /* Now save it and build the enclosing record type. */
1722 /* Propagate the alignment of the modular type to the record type,
1723 unless there is an alignment clause that under-aligns the type.
1724 This means that bit-packed arrays are given "ceil" alignment for
1725 their size by default, which may seem counter-intuitive but makes
1726 it possible to overlay them on modular types easily. */
1732 /* Don't declare the field as addressable since we won't be taking
1733 its address and this would prevent create_field_decl from making
1734 a bitfield. */
1735 gnu_field
1739 /* Do not emit debug info until after the parallel type is added. */
1745 {
1746 /* Make the original array type a parallel type. */
1749 gnat_to_gnu_type
1753 }
1754 }
1756 /* If the type we are dealing with has got a smaller alignment than the
1757 natural one, we need to wrap it up in a record type and under-align
1758 the latter. We reuse the padding machinery for this purpose. */
1760 {
1763 /* Set the RM size before wrapping up the type. */
1767 /* Create a stripped-down declaration, mainly for debugging. */
1771 /* Now save it and build the enclosing record type. */
1783 /* Don't declare the field as addressable since we won't be taking
1784 its address and this would prevent create_field_decl from making
1785 a bitfield. */
1786 gnu_field
1793 }
1798 /* If this is a VAX floating-point type, use an integer of the proper
1799 size. All the operations will be handled with ASM statements. */
1801 {
1806 sizetype));
1808 }
1810 /* The type of the Low and High bounds can be our type if this is
1811 a type from Standard, so set them at the end of the function. */
1819 {
1822 }
1824 {
1842 SET_TYPE_RM_MIN_VALUE
1850 SET_TYPE_RM_MAX_VALUE
1858 /* One of the above calls might have caused us to be elaborated,
1859 so don't blow up if so. */
1861 {
1864 }
1866 /* Inherit our alias set from what we're a subtype of, as for
1867 integer subtypes. */
1869 }
1872 /* Array and String Types and Subtypes
1874 Unconstrained array types are represented by E_Array_Type and
1875 constrained array types are represented by E_Array_Subtype. There
1876 are no actual objects of an unconstrained array type; all we have
1877 are pointers to that type.
1879 The following fields are defined on array types and subtypes:
1881 Component_Type Component type of the array.
1882 Number_Dimensions Number of dimensions (an int).
1883 First_Index Type of first index. */
1887 {
1889 const bool convention_fortran_p
1894 tree gnu_template_reference;
1905 /* Make a node for the array. If we are not defining the array
1906 suppress expanding incomplete types. */
1910 {
1911 defer_incomplete_level++;
1913 }
1915 /* Build the fat pointer type. Use a "void *" object instead of
1916 a pointer to the array type since we don't have the array type
1917 yet (it will reference the fat pointer via the bounds). */
1920 ptr_void_type_node,
1924 gnu_ptr_template,
1928 /* Make sure we can put this into a register. */
1931 /* Do not emit debug info for this record type since the types of its
1932 fields are still incomplete at this point. */
1936 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1937 is the fat pointer. This will be used to access the individual
1938 fields once we build them. */
1942 gnu_template_reference
1946 /* Now create the GCC type for each index and add the fields for that
1947 index to the template. */
1953 {
1955 tree gnu_index_base_type
1960 /* Make the FIELD_DECLs for the low and high bounds of this
1961 type and then make extractions of these fields from the
1962 template. */
1965 gnu_index_base_type,
1973 gnu_index_base_type,
1981 /* We can't use build_component_ref here since the template type
1982 isn't complete yet. */
1985 NULL_TREE);
1988 NULL_TREE);
1994 /* Compute the size of this dimension. See the E_Array_Subtype
1995 case below for the rationale. */
1996 gnu_high
2000 gnu_max,
2003 /* Make a range type with the new range in the Ada base type.
2004 Then make an index type with the size range in sizetype. */
2008 gnu_orig_min,
2009 gnu_orig_max),
2010 gnat_entity);
2012 /* Update the maximum size of the array in elements. */
2014 {
2016 tree gnu_min
2018 tree gnu_max
2020 tree gnu_this_max
2025 size_zero_node);
2030 else
2031 gnu_max_size
2033 }
2037 }
2040 gnu_template_fields
2043 /* Install all the fields into the template. */
2045 debug_info_p);
2048 /* Now make the array of arrays and update the pointer to the array
2049 in the fat pointer. Note that it is the first field. */
2051 debug_info_p);
2053 /* If Component_Size is not already specified, annotate it with the
2054 size of the component. */
2058 /* Compute the maximum size of the array in units and bits. */
2060 {
2066 }
2067 else
2070 /* Now build the array type. */
2072 {
2077 }
2079 /* If an alignment is specified, use it if valid. But ignore it
2080 for the original type of packed array types. If the alignment
2081 was requested with an explicit alignment clause, state so. */
2084 {
2090 }
2095 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2096 corresponding fat pointer. */
2103 /* If the maximum size doesn't overflow, use it. */
2109 {
2114 }
2120 /* Give the fat pointer type a name. If this is a packed type, tell
2121 the debugger how to interpret the underlying bits. */
2124 else
2130 /* Create the type to be used as what a thin pointer designates:
2131 a record type for the object and its template with the fields
2132 shifted to have the template at a negative offset. */
2135 debug_info_p);
2140 }
2146 /* This is the actual data type for array variables. Multidimensional
2147 arrays are implemented as arrays of arrays. Note that arrays which
2148 have sparse enumeration subtypes as index components create sparse
2149 arrays, which is obviously space inefficient but so much easier to
2150 code for now.
2152 Also note that the subtype never refers to the unconstrained array
2153 type, which is somewhat at variance with Ada semantics.
2155 First check to see if this is simply a renaming of the array type.
2156 If so, the result is the array type. */
2160 ;
2161 else
2162 {
2164 const bool convention_fortran_p
2173 /* First create the GCC type for each index and find out whether
2174 special types are needed for debugging information. */
2177 gnat_base_index
2183 {
2189 tree gnu_base_index_type
2193 tree gnu_high;
2195 /* See if the base array type is already flat. If it is, we
2196 are probably compiling an ACATS test but it will cause the
2197 code below to malfunction if we don't handle it specially. */
2201 {
2205 }
2207 /* Similarly, if one of the values overflows in sizetype and the
2208 range is null, use 1..0 for the sizetype bounds. */
2213 {
2217 }
2219 /* If the minimum and maximum values both overflow in sizetype,
2220 but the difference in the original type does not overflow in
2221 sizetype, ignore the overflow indication. */
2225 && !TREE_OVERFLOW
2228 gnu_orig_max,
2229 gnu_orig_min))))
2230 {
2234 }
2236 /* Compute the size of this dimension in the general case. We
2237 need to provide GCC with an upper bound to use but have to
2238 deal with the "superflat" case. There are three ways to do
2239 this. If we can prove that the array can never be superflat,
2240 we can just use the high bound of the index type. */
2243 /* Packed Array Types are never superflat. */
2247 /* Otherwise, if the high bound is constant but the low bound is
2248 not, we use the expression (hb >= lb) ? lb : hb + 1 for the
2249 lower bound. Note that the comparison must be done in the
2250 original type to avoid any overflow during the conversion. */
2253 {
2255 gnu_min
2258 boolean_type_node,
2259 gnu_orig_max,
2260 gnu_orig_min),
2261 gnu_min,
2263 size_one_node));
2264 }
2266 /* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
2267 in all the other cases. Note that, here as well as above,
2268 the condition used in the comparison must be equivalent to
2269 the condition (length != 0). This is relied upon in order
2270 to optimize array comparisons in compare_arrays. */
2271 else
2272 gnu_high
2275 boolean_type_node,
2276 gnu_orig_max,
2277 gnu_orig_min),
2278 gnu_max,
2280 size_one_node));
2282 /* Reuse the index type for the range type. Then make an index
2283 type with the size range in sizetype. */
2286 gnat_entity);
2288 /* Update the maximum size of the array in elements. Here we
2289 see if any constraint on the index type of the base type
2290 can be used in the case of self-referential bound on the
2291 index type of the subtype. We look for a non-"infinite"
2292 and non-self-referential bound from any type involved and
2293 handle each bound separately. */
2295 {
2298 tree gnu_base_index_base_type
2300 tree gnu_base_base_min
2303 tree gnu_base_base_max
2324 else
2325 {
2326 tree gnu_this_max
2330 gnu_base_max,
2331 gnu_base_min)),
2332 size_zero_node);
2337 else
2338 gnu_max_size
2340 }
2341 }
2343 /* We need special types for debugging information to point to
2344 the index types if they have variable bounds, are not integer
2345 types, are biased or are wider than sizetype. */
2356 }
2358 /* Then flatten: create the array of arrays. For an array type
2359 used to implement a packed array, get the component type from
2360 the original array type since the representation clauses that
2361 can affect it are on the latter. */
2364 {
2369 /* One of the above calls might have caused us to be elaborated,
2370 so don't blow up if so. */
2372 {
2375 }
2376 }
2377 else
2378 {
2380 debug_info_p);
2382 /* One of the above calls might have caused us to be elaborated,
2383 so don't blow up if so. */
2385 {
2388 }
2389 }
2391 /* Compute the maximum size of the array in units and bits. */
2393 {
2399 }
2400 else
2403 /* Now build the array type. */
2405 {
2411 }
2413 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
2417 /* If we are at file level and this is a multi-dimensional array,
2418 we need to make a variable corresponding to the stride of the
2419 inner dimensions. */
2421 {
2423 tree gnu_arr_type;
2429 {
2437 /* ??? For now, store the size as a multiple of the
2438 alignment of the element type in bytes so that we
2439 can see the alignment from the tree. */
2442 gnat_entity,
2447 /* ??? create_type_decl is not invoked on the inner types so
2448 the MULT_EXPR node built above will never be marked. */
2450 }
2451 }
2453 /* If we need to write out a record type giving the names of the
2454 bounds for debugging purposes, do it now and make the record
2455 type a parallel type. This is not needed for a packed array
2456 since the bounds are conveyed by the original array type. */
2458 && debug_info_p
2460 {
2463 tree gnu_field;
2469 {
2476 /* Make sure to reference the types themselves, and not just
2477 their names, as the debugger may fall back on them. */
2483 }
2487 }
2489 /* Otherwise, for a packed array, make the original array type a
2490 parallel type. */
2495 gnat_to_gnu_type
2503 /* If the size is self-referential and the maximum size doesn't
2504 overflow, use it. */
2506 && gnu_max_size
2511 {
2517 }
2519 /* Set our alias set to that of our base type. This gives all
2520 array subtypes the same alias set. */
2523 /* If this is a packed type, make this type the same as the packed
2524 array type, but do some adjusting in the type first. */
2526 {
2527 Entity_Id gnat_index;
2528 tree gnu_inner;
2530 /* First finish the type we had been making so that we output
2531 debugging information for it. */
2533 gnu_type
2538 /* Make it artificial only if the base type was artificial too.
2539 That's sort of "morally" true and will make it possible for
2540 the debugger to look it up by name in DWARF, which is needed
2541 in order to decode the packed array type. */
2542 gnu_decl
2548 /* Save it as our equivalent in case the call below elaborates
2549 this type again. */
2564 /* We need to attach the index type to the type we just made so
2565 that the actual bounds can later be put into a template. */
2570 {
2572 {
2573 /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
2574 TYPE_MODULUS for modular types so we make an extra
2575 subtype if necessary. */
2577 {
2578 tree gnu_subtype
2587 }
2591 #ifdef ENABLE_CHECKING
2592 /* Check for other cases of overloading. */
2594 #endif
2595 }
2600 SET_TYPE_ACTUAL_BOUNDS
2607 SET_TYPE_ACTUAL_BOUNDS
2613 }
2614 }
2616 else
2617 /* Abort if packed array with no Packed_Array_Type field set. */
2619 }
2623 /* Create the type for a string literal. */
2624 {
2625 Entity_Id gnat_full_type
2630 tree gnu_string_array_type
2632 tree gnu_string_index_type
2635 tree gnu_lower_bound
2640 tree gnu_upper_bound
2642 gnu_lower_bound,
2644 tree gnu_index_type
2648 gnu_lower_bound,
2649 gnu_upper_bound),
2650 gnat_entity);
2652 gnu_type
2655 gnu_index_type);
2659 }
2662 /* Record Types and Subtypes
2664 The following fields are defined on record types:
2666 Has_Discriminants True if the record has discriminants
2667 First_Discriminant Points to head of list of discriminants
2668 First_Entity Points to head of list of fields
2669 Is_Tagged_Type True if the record is tagged
2671 Implementation of Ada records and discriminated records:
2673 A record type definition is transformed into the equivalent of a C
2674 struct definition. The fields that are the discriminants which are
2675 found in the Full_Type_Declaration node and the elements of the
2676 Component_List found in the Record_Type_Definition node. The
2677 Component_List can be a recursive structure since each Variant of
2678 the Variant_Part of the Component_List has a Component_List.
2680 Processing of a record type definition comprises starting the list of
2681 field declarations here from the discriminants and the calling the
2682 function components_to_record to add the rest of the fields from the
2683 component list and return the gnu type node. The function
2684 components_to_record will call itself recursively as it traverses
2685 the tree. */
2689 {
2690 gnu_type
2691 = build_complex_type
2692 (get_unpadded_type
2695 (Component_List
2696 (Type_Definition
2700 }
2702 {
2705 Entity_Id gnat_field;
2707 /* Set PACKED in keeping with gnat_to_gnu_field. */
2708 int packed
2721 bool is_extension
2726 /* See if all fields have a rep clause. Stop when we find one
2727 that doesn't. */
2735 {
2738 }
2740 /* If this is a record extension, go a level further to find the
2741 record definition. Also, verify we have a Parent_Subtype. */
2743 {
2750 }
2752 /* Make a node for the record. If we are not defining the record,
2753 suppress expanding incomplete types. */
2759 {
2760 defer_incomplete_level++;
2762 }
2764 /* If both a size and rep clause was specified, put the size in
2765 the record type now so that it can get the proper mode. */
2769 /* Always set the alignment here so that it can be used to
2770 set the mode, if it is making the alignment stricter. If
2771 it is invalid, it will be checked again below. If this is to
2772 be Atomic, choose a default alignment of a word unless we know
2773 the size and it's smaller. */
2780 /* If a type needs strict alignment, the minimum size will be the
2781 type size instead of the RM size (see validate_size). Cap the
2782 alignment, lest it causes this type size to become too large. */
2785 {
2790 }
2791 else
2794 /* If we have a Parent_Subtype, make a field for the parent. If
2795 this record has rep clauses, force the position to zero. */
2797 {
2799 tree gnu_parent;
2801 /* A major complexity here is that the parent subtype will
2802 reference our discriminants in its Discriminant_Constraint
2803 list. But those must reference the parent component of this
2804 record which is of the parent subtype we have not built yet!
2805 To break the circle we first build a dummy COMPONENT_REF which
2806 represents the "get to the parent" operation and initialize
2807 each of those discriminants to a COMPONENT_REF of the above
2808 dummy parent referencing the corresponding discriminant of the
2809 base type of the parent subtype. */
2814 void_type_node),
2815 NULL_TREE);
2822 {
2823 tree gnu_field
2826 save_gnu_tree
2831 }
2833 /* Then we build the parent subtype. If it has discriminants but
2834 the type itself has unknown discriminants, this means that it
2835 doesn't contain information about how the discriminants are
2836 derived from those of the ancestor type, so it cannot be used
2837 directly. Instead it is built by cloning the parent subtype
2838 of the underlying record view of the type, for which the above
2839 derivation of discriminants has been made explicit. */
2842 {
2845 /* If we are defining the type, the underlying record
2846 view must already have been elaborated at this point.
2847 Otherwise do it now as its parent subtype cannot be
2848 technically elaborated on its own. */
2851 else
2856 /* Substitute the "get to the parent" of the type for that
2857 of its underlying record view in the cloned type. */
2862 {
2864 tree gnu_ref
2867 gnu_parent
2869 }
2870 }
2871 else
2874 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
2875 initially built. The discriminants must reference the fields
2876 of the parent subtype and not those of its base type for the
2877 placeholder machinery to properly work. */
2879 {
2880 /* The actual parent subtype is the full view. */
2882 {
2885 else
2887 }
2893 {
2903 }
2904 }
2906 /* The "get to the parent" COMPONENT_REF must be given its
2907 proper type... */
2910 /* ...and reference the _Parent field of this record. */
2911 gnu_field
2914 has_rep
2916 has_rep
2922 }
2924 /* Make the fields for the discriminants and put them into the record
2925 unless it's an Unchecked_Union. */
2930 {
2931 /* If this is a record extension and this discriminant is the
2932 renaming of another discriminant, we've handled it above. */
2937 gnu_field
2939 debug_info_p);
2941 /* Make an expression using a PLACEHOLDER_EXPR from the
2942 FIELD_DECL node just created and link that with the
2943 corresponding GNAT defining identifier. */
2951 {
2954 }
2955 }
2957 /* Add the fields into the record type and finish it up. */
2963 /* If it is passed by reference, force BLKmode to ensure that objects
2964 of this type will always be put in memory. */
2968 /* We used to remove the associations of the discriminants and _Parent
2969 for validity checking but we may need them if there's a Freeze_Node
2970 for a subtype used in this record. */
2973 /* Fill in locations of fields. */
2976 /* If there are any entities in the chain corresponding to components
2977 that we did not elaborate, ensure we elaborate their types if they
2978 are Itypes. */
2988 /* If this is a record type associated with an exception definition,
2989 equate its fields to those of the standard exception type. This
2990 will make it possible to convert between them. */
2992 {
2993 tree gnu_std_field;
2996 gnu_field;
3001 }
3002 }
3006 /* If an equivalent type is present, that is what we should use.
3007 Otherwise, fall through to handle this like a record subtype
3008 since it may have constraints. */
3010 {
3014 }
3016 /* ... fall through ... */
3019 /* If Cloned_Subtype is Present it means this record subtype has
3020 identical layout to that type or subtype and we should use
3021 that GCC type for this one. The front end guarantees that
3022 the component list is shared. */
3024 {
3029 }
3031 /* Otherwise, first ensure the base type is elaborated. Then, if we are
3032 changing the type, make a new type with each field having the type of
3033 the field in the new subtype but the position computed by transforming
3034 every discriminant reference according to the constraints. We don't
3035 see any difference between private and non-private type here since
3036 derivations from types should have been deferred until the completion
3037 of the private type. */
3038 else
3039 {
3041 tree gnu_base_type;
3044 {
3045 defer_incomplete_level++;
3047 }
3052 {
3055 }
3057 /* If this is a record subtype associated with a dispatch table,
3058 strip the suffix. This is necessary to make sure 2 different
3059 subtypes associated with the imported and exported views of a
3060 dispatch table are properly merged in LTO mode. */
3062 {
3069 }
3071 /* When the subtype has discriminants and these discriminants affect
3072 the initial shape it has inherited, factor them in. But for an
3073 Unchecked_Union (it must be an Itype), just return the type.
3074 We can't just test Is_Constrained because private subtypes without
3075 discriminants of types with discriminants with default expressions
3076 are Is_Constrained but aren't constrained! */
3084 {
3090 Entity_Id gnat_field;
3096 /* Set the size, alignment and alias set of the new type to
3097 match that of the old one, doing required substitutions. */
3099 gnu_subst_list);
3103 else
3106 /* Look for a REP part in the base type. */
3109 /* Look for a variant part in the base type. */
3112 /* If there is a variant part, we must compute whether the
3113 constraints statically select a particular variant. If
3114 so, we simply drop the qualified union and flatten the
3115 list of fields. Otherwise we'll build a new qualified
3116 union for the variants that are still relevant. */
3118 {
3122 gnu_variant_list
3126 /* If all the qualifiers are unconditionally true, the
3127 innermost variant is statically selected. */
3132 {
3135 }
3137 /* Otherwise, create the new variants. */
3141 {
3147 gnu_subst_list);
3149 }
3150 }
3151 else
3152 {
3155 }
3157 gnu_pos_list
3173 {
3175 Entity_Id gnat_old_field
3177 tree gnu_old_field
3183 /* If the type is the same, retrieve the GCC type from the
3184 old field to take into account possible adjustments. */
3187 else
3190 /* If there was a component clause, the field types must be
3191 the same for the type and subtype, so copy the data from
3192 the old field to avoid recomputation here. Also if the
3193 field is justified modular and the optimization in
3194 gnat_to_gnu_field was applied. */
3200 {
3203 }
3205 /* If the old field was packed and of constant size, we
3206 have to get the old size here, as it might differ from
3207 what the Etype conveys and the latter might overlap
3208 onto the following field. Try to arrange the type for
3209 possible better packing along the way. */
3213 {
3218 gnu_field_type
3220 }
3222 else
3225 /* If the context of the old field is the base type or its
3226 REP part (if any), put the field directly in the new
3227 type; otherwise look up the context in the variant list
3228 and put the field either in the new type if there is a
3229 selected variant or in one of the new variants. */
3231 || (gnu_rep_part
3234 else
3235 {
3243 {
3246 }
3248 {
3251 else
3253 }
3254 else
3255 /* The front-end may pass us "ghost" components if
3256 it fails to recognize that a constrained subtype
3257 is statically constrained. Discard them. */
3259 }
3261 /* Now create the new field modeled on the old one. */
3262 gnu_field
3267 /* Put it in one of the new variants directly. */
3269 {
3272 }
3274 /* To match the layout crafted in components_to_record,
3275 if this is the _Tag or _Parent field, put it before
3276 any other fields. */
3281 /* Similarly, if this is the _Controller field, put
3282 it before the other fields except for the _Tag or
3283 _Parent field. */
3285 {
3288 }
3290 /* Otherwise, if this is a regular field, put it after
3291 the other fields. */
3292 else
3293 {
3298 }
3301 }
3303 /* If there is a variant list and no selected variant, we need
3304 to create the nest of variant parts from the old nest. */
3306 {
3307 tree new_variant_part
3313 }
3315 /* Now go through the entities again looking for Itypes that
3316 we have not elaborated but should (e.g., Etypes of fields
3317 that have Original_Components). */
3325 /* Do not emit debug info for the type yet since we're going to
3326 modify it below. */
3330 /* See the E_Record_Type case for the rationale. */
3333 else
3338 /* Fill in locations of fields. */
3341 /* If debugging information is being written for the type, write
3342 a record that shows what we are a subtype of and also make a
3343 variable that indicates our size, if still variable. */
3345 {
3357 build_reference_type
3359 gnu_subtype_marker,
3365 gnu_subtype_marker);
3375 gnat_entity);
3376 }
3381 /* Now we can finalize it. */
3383 }
3385 /* Otherwise, go down all the components in the new type and make
3386 them equivalent to those in the base type. */
3387 else
3388 {
3398 gnat_to_gnu_field_decl
3401 }
3402 }
3406 /* Use the special descriptor type for dispatch tables if needed,
3407 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3408 Note that we are only required to do so for static tables in
3409 order to be compatible with the C++ ABI, but Ada 2005 allows
3410 to extend library level tagged types at the local level so
3411 we do it in the non-static case as well. */
3414 {
3418 }
3420 /* ... fall through ... */
3423 /* If we are not defining this entity, and we have incomplete
3424 entities being processed above us, make a dummy type and
3425 fill it in later. */
3427 {
3431 gnu_type
3432 = build_pointer_type
3447 }
3449 /* ... fall through ... */
3456 {
3457 /* The designated type and its equivalent type for gigi. */
3460 /* Whether it comes from a limited with. */
3461 bool is_from_limited_with
3464 /* The "full view" of the designated type. If this is an incomplete
3465 entity from a limited with, treat its non-limited view as the full
3466 view. Otherwise, if this is an incomplete or private type, use the
3467 full view. In the former case, we might point to a private type,
3468 in which case, we need its full view. Also, we want to look at the
3469 actual type used for the representation, so this takes a total of
3470 three steps. */
3471 Entity_Id gnat_desig_full_direct_first
3472 = (is_from_limited_with
3476 Entity_Id gnat_desig_full_direct
3477 = ((is_from_limited_with
3482 Entity_Id gnat_desig_full
3484 /* The type actually used to represent the designated type, either
3485 gnat_desig_full or gnat_desig_equiv. */
3486 Entity_Id gnat_desig_rep;
3487 /* True if this is a pointer to an unconstrained array. */
3489 /* We want to know if we'll be seeing the freeze node for any
3490 incomplete type we may be pointing to. */
3491 bool in_main_unit
3495 /* True if we make a dummy type here. */
3497 /* True if the dummy type is a fat pointer. */
3499 /* The mode to be used for the pointer type. */
3501 /* The GCC type used for the designated type. */
3507 /* If either the designated type or its full view is an unconstrained
3508 array subtype, replace it with the type it's a subtype of. This
3509 avoids problems with multiple copies of unconstrained array types.
3510 Likewise, if the designated type is a subtype of an incomplete
3511 record type, use the parent type to avoid order of elaboration
3512 issues. This can lose some code efficiency, but there is no
3513 alternative. */
3524 /* Set the type that's actually the representation of the designated
3525 type and also flag whether we have a unconstrained array. */
3526 gnat_desig_rep
3528 is_unconstrained_array
3531 /* If we are pointing to an incomplete type whose completion is an
3532 unconstrained array, make a fat pointer type. The two types in our
3533 fields will be pointers to dummy nodes and will be replaced in
3534 update_pointer_to. Similarly, if the type itself is a dummy type or
3535 an unconstrained array. Also make a dummy TYPE_OBJECT_RECORD_TYPE
3536 in case we have any thin pointers to it. */
3540 && TYPE_IS_DUMMY_P
3542 || (!in_main_unit
3545 || (in_main_unit
3546 && is_from_limited_with
3548 {
3551 else
3552 {
3554 /* Show the dummy we get will be a fat pointer. */
3556 }
3558 /* If the call above got something that has a pointer, the pointer
3559 is our type. This could have happened either because the type
3560 was elaborated or because somebody else executed the code. */
3563 {
3568 tree fields;
3582 fields
3591 /* Make sure we can place this into a register. */
3596 /* Do not emit debug info for this record type since the types
3597 of its fields are incomplete. */
3605 }
3606 }
3608 /* If we already know what the full type is, use it. */
3613 /* Get the type of the thing we are to point to and build a pointer to
3614 it. If it is a reference to an incomplete or private type with a
3615 full view that is a record, make a dummy type node and get the
3616 actual type later when we have verified it is safe. */
3622 /* Likewise if we are pointing to a record or array and we are
3623 to defer elaborating incomplete types. We do this as this
3624 access type may be the full view of a private type. Note
3625 that the unconstrained array case is handled above. */
3631 /* If this is a reference from a limited_with type back to our
3632 main unit and there's a freeze node for it, either we have
3633 already processed the declaration and made the dummy type,
3634 in which case we just reuse the latter, or we have not yet,
3635 in which case we make the dummy type and it will be reused
3636 when the declaration is finally processed. In both cases,
3637 the pointer eventually created below will be automatically
3638 adjusted when the freeze node is processed. Note that the
3639 unconstrained array case is handled above. */
3640 || (in_main_unit
3641 && is_from_limited_with
3643 {
3646 }
3648 /* Otherwise handle the case of a pointer to itself. */
3650 {
3651 gnu_type
3655 }
3657 /* If expansion is disabled, the equivalent type of a concurrent type
3658 is absent, so build a dummy pointer type. */
3662 /* Finally, handle the default case where we can just elaborate our
3663 designated type. */
3664 else
3667 /* It is possible that a call to gnat_to_gnu_type above resolved our
3668 type. If so, just return it. */
3670 {
3673 }
3675 /* If we have not done it yet, build the pointer type the usual way. */
3677 {
3678 /* Modify the designated type if we are pointing only to constant
3679 objects, but don't do it for unconstrained arrays. */
3682 {
3683 gnu_desig_type
3684 = build_qualified_type
3688 /* Some extra processing is required if we are building a
3689 pointer to an incomplete type (in the GCC sense). We might
3690 have such a type if we just made a dummy, or directly out
3691 of the call to gnat_to_gnu_type above if we are processing
3692 an access type for a record component designating the
3693 record type itself. */
3695 {
3696 /* We must ensure that the pointer to variant we make will
3697 be processed by update_pointer_to when the initial type
3698 is completed. Pretend we made a dummy and let further
3699 processing act as usual. */
3702 /* We must ensure that update_pointer_to will not retrieve
3703 the dummy variant when building a properly qualified
3704 version of the complete type. We take advantage of the
3705 fact that get_qualified_type is requiring TYPE_NAMEs to
3706 match to influence build_qualified_type and then also
3707 update_pointer_to here. */
3710 }
3711 }
3713 gnu_type
3716 }
3718 /* If we are not defining this object and we have made a dummy pointer,
3719 save our current definition, evaluate the actual type, and replace
3720 the tentative type we made with the actual one. If we are to defer
3721 actually looking up the actual type, make an entry in the deferred
3722 list. If this is from a limited with, we have to defer to the end
3723 of the current spec in two cases: first if the designated type is
3724 in the current unit and second if the access type itself is. */
3726 {
3727 bool is_from_limited_with_in_main_unit
3728 = (is_from_limited_with
3729 && (in_main_unit
3731 tree gnu_old_desig_type
3737 gnu_type
3738 = build_pointer_type
3739 (TYPE_OBJECT_RECORD_TYPE
3750 /* Note that the call to gnat_to_gnu_type on gnat_desig_equiv might
3751 update gnu_old_desig_type directly, in which case it will not be
3752 a dummy type any more when we get into update_pointer_to.
3754 This can happen e.g. when the designated type is a record type,
3755 because their elaboration starts with an initial node from
3756 make_dummy_type, which may be the same node as the one we got.
3758 Besides, variants of this non-dummy type might have been created
3759 along the way. update_pointer_to is expected to properly take
3760 care of those situations. */
3765 else
3766 {
3769 = (is_from_limited_with_in_main_unit
3775 }
3776 }
3777 }
3784 else
3785 {
3786 /* The run-time representation is the equivalent type. */
3789 }
3802 /* We treat this as identical to its base type; any constraint is
3803 meaningful only to the front end.
3805 The designated type must be elaborated as well, if it does
3806 not have its own freeze node. Designated (sub)types created
3807 for constrained components of records with discriminants are
3808 not frozen by the front end and thus not elaborated by gigi,
3809 because their use may appear before the base type is frozen,
3810 and because it is not clear that they are needed anywhere in
3811 Gigi. With the current model, there is no correct place where
3812 they could be elaborated. */
3819 {
3820 /* If we are not defining this entity, and we have incomplete
3821 entities being processed above us, make a dummy type and
3822 elaborate it later. */
3824 {
3827 tree gnu_ptr_type
3828 = build_pointer_type
3835 }
3838 Incomplete_Or_Private_Kind))
3841 }
3846 /* Subprogram Entities
3848 The following access functions are defined for subprograms (functions
3849 or procedures):
3851 First_Formal The first formal parameter.
3852 Is_Imported Indicates that the subprogram has appeared in
3853 an INTERFACE or IMPORT pragma. For now we
3854 assume that the external language is C.
3855 Is_Exported Likewise but for an EXPORT pragma.
3856 Is_Inlined True if the subprogram is to be inlined.
3858 In addition for function subprograms we have:
3860 Etype Return type of the function.
3862 Each parameter is first checked by calling must_pass_by_ref on its
3863 type to determine if it is passed by reference. For parameters which
3864 are copied in, if they are Ada In Out or Out parameters, their return
3865 value becomes part of a record which becomes the return type of the
3866 function (C function - note that this applies only to Ada procedures
3867 so there is no Ada return type). Additional code to store back the
3868 parameters will be generated on the caller side. This transformation
3869 is done here, not in the front-end.
3871 The intended result of the transformation can be seen from the
3872 equivalent source rewritings that follow:
3874 struct temp {int a,b};
3875 procedure P (A,B: In Out ...) is temp P (int A,B)
3876 begin {
3877 .. ..
3878 end P; return {A,B};
3879 }
3881 temp t;
3882 P(X,Y); t = P(X,Y);
3883 X = t.a , Y = t.b;
3885 For subprogram types we need to perform mainly the same conversions to
3886 GCC form that are needed for procedures and function declarations. The
3887 only difference is that at the end, we make a type declaration instead
3888 of a function declaration. */
3893 {
3894 /* The first GCC parameter declaration (a PARM_DECL node). The
3895 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3896 actually is the head of this parameter list. */
3898 /* Likewise for the stub associated with an exported procedure. */
3900 /* The type returned by a function. If the subprogram is a procedure
3901 this type should be void_type_node. */
3903 /* List of fields in return type of procedure with copy-in copy-out
3904 parameters. */
3906 /* Non-null for subprograms containing parameters passed by copy-in
3907 copy-out (Ada In Out or Out parameters not passed by reference),
3908 in which case it is the list of nodes used to specify the values
3909 of the In Out/Out parameters that are returned as a record upon
3910 procedure return. The TREE_PURPOSE of an element of this list is
3911 a field of the record and the TREE_VALUE is the PARM_DECL
3912 corresponding to that field. This list will be saved in the
3913 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3915 /* If an import pragma asks to map this subprogram to a GCC builtin,
3916 this is the builtin DECL node. */
3918 /* For the stub associated with an exported procedure. */
3921 Entity_Id gnat_param;
3924 bool extern_flag
3927 /* The semantics of "pure" in Ada essentially matches that of "const"
3928 in the back-end. In particular, both properties are orthogonal to
3929 the "nothrow" property if the EH circuitry is explicit in the
3930 internal representation of the back-end. If we are to completely
3931 hide the EH circuitry from it, we need to declare that calls to pure
3932 Ada subprograms that can throw have side effects since they can
3933 trigger an "abnormal" transfer of control flow; thus they can be
3934 neither "const" nor "pure" in the back-end sense. */
3935 bool const_flag
3947 /* A parameter may refer to this type, so defer completion of any
3948 incomplete types. */
3950 {
3951 defer_incomplete_level++;
3953 }
3955 /* If the subprogram has an alias, it is probably inherited, so
3956 we can use the original one. If the original "subprogram"
3957 is actually an enumeration literal, it may be the first use
3958 of its type, so we must elaborate that type now. */
3960 {
3967 /* Elaborate any Itypes in the parameters of this entity. */
3975 }
3977 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3978 corresponding DECL node. Proper generation of calls later on need
3979 proper parameter associations so we don't "break;" here. */
3982 {
3985 /* Unability to find the builtin decl most often indicates a
3986 genuine mistake, but imports of unregistered intrinsics are
3987 sometimes issued on purpose to allow hooking in alternate
3988 bodies. We post a warning conditioned on Wshadow in this case,
3989 to let developers be notified on demand without risking false
3990 positives with common default sets of options. */
3994 }
3996 /* ??? What if we don't find the builtin node above ? warn ? err ?
3997 In the current state we neither warn nor err, and calls will just
3998 be handled as for regular subprograms. */
4003 /* If this function returns by reference, make the actual return
4004 type of this function the pointer and mark the decl. */
4006 {
4009 }
4011 /* If the Mechanism is By_Reference, ensure this function uses the
4012 target's by-invisible-reference mechanism, which may not be the
4013 same as above (e.g. it might be passing an extra parameter).
4015 Prior to GCC 4, this was handled by just setting TREE_ADDRESSABLE
4016 on the result type. Everything required to pass by invisible
4017 reference using the target's mechanism (e.g. an extra parameter)
4018 was handled at RTL expansion time.
4020 This doesn't work with GCC 4 any more for several reasons. First,
4021 the gimplification process might need to create temporaries of this
4022 type and the gimplifier ICEs on such attempts; that's why the flag
4023 is now set on the function type instead. Second, the middle-end
4024 now also relies on a different attribute, DECL_BY_REFERENCE on the
4025 RESULT_DECL, and expects the by-invisible-reference-ness to be made
4026 explicit in the function body. */
4030 /* If we are supposed to return an unconstrained array, actually return
4031 a fat pointer and make a note of that. */
4033 {
4036 }
4038 /* If the type requires a transient scope, the result is allocated
4039 on the secondary stack, so the result type of the function is
4040 just a pointer. */
4042 {
4045 }
4047 /* If the type is a padded type and the underlying type would not
4048 be passed by reference or this function has a foreign convention,
4049 return the underlying type. */
4056 /* If the return type is unconstrained, that means it must have a
4057 maximum size. Use the padded type as the effective return type.
4058 And ensure the function uses the target's by-invisible-reference
4059 mechanism to avoid copying too much data when it returns. */
4061 {
4062 gnu_return_type
4067 }
4069 /* If the return type has a size that overflows, we cannot have
4070 a function that returns that type. This usage doesn't make
4071 sense anyway, so give an error here. */
4075 {
4077 gnat_entity);
4083 }
4085 /* Look at all our parameters and get the type of
4086 each. While doing this, build a copy-out structure if
4087 we need one. */
4089 /* Loop over the parameters and get their associated GCC tree.
4090 While doing this, build a copy-out structure if we need one. */
4094 {
4101 /* Builtins are expanded inline and there is no real call sequence
4102 involved. So the type expected by the underlying expander is
4103 always the type of each argument "as is". */
4106 /* Handle the first parameter of a valued procedure specially. */
4109 /* Otherwise, see if a Mechanism was supplied that forced this
4110 parameter to be passed one way or another. */
4113 ;
4122 {
4126 mech))
4128 else
4130 }
4131 else
4132 {
4135 }
4137 gnu_param
4142 /* We are returned either a PARM_DECL or a type if no parameter
4143 needs to be passed; in either case, adjust the type. */
4146 else
4147 {
4150 }
4152 /* The failure of this assertion will very likely come from an
4153 order of elaboration issue for the type of the parameter. */
4158 {
4159 /* If it's an exported subprogram, we build a parameter list
4160 in parallel, in case we need to emit a stub for it. */
4162 {
4163 gnu_stub_param_list
4165 /* Change By_Descriptor parameter to By_Reference for
4166 the internal version of an exported subprogram. */
4168 {
4169 gnu_param
4174 }
4175 else
4177 }
4184 /* If a parameter is a pointer, this function may modify
4185 memory through it and thus shouldn't be considered
4186 a const function. Also, the memory may be modified
4187 between two calls, so they can't be CSE'ed. The latter
4188 case also handles by-ref parameters. */
4192 }
4195 {
4197 {
4201 /* Set a default alignment to speed up accesses. */
4205 }
4207 gnu_field
4215 gnu_cico_list
4217 }
4218 }
4220 /* Do not compute record for out parameters if subprogram is
4221 stubbed since structures are incomplete for the back-end. */
4226 /* If we have a CICO list but it has only one entry, we convert
4227 this function into a function that simply returns that one
4228 object. */
4233 prepend_one_attribute_to
4236 gnat_entity);
4238 /* If we should request stack realignment for a foreign convention
4239 subprogram, do so. Note that this applies to task entry points in
4240 particular. */
4243 prepend_one_attribute_to
4246 gnat_entity);
4248 /* The lists have been built in reverse. */
4256 || return_by_direct_ref_p
4257 || return_by_invisi_ref_p
4259 gnu_type
4262 return_by_direct_ref_p,
4263 return_by_invisi_ref_p);
4266 gnu_stub_type
4269 return_by_direct_ref_p,
4270 return_by_invisi_ref_p);
4272 /* A subprogram (something that doesn't return anything) shouldn't
4273 be considered const since there would be no reason for such a
4274 subprogram. Note that procedures with Out (or In Out) parameters
4275 have already been converted into a function with a return type. */
4279 gnu_type
4286 gnu_stub_type
4292 /* If we have a builtin decl for that function, use it. Check if the
4293 profiles are compatible and warn if they are not. The checker is
4294 expected to post extra diagnostics in this case. */
4296 {
4297 intrin_binding_t inb;
4304 post_error
4306 gnat_entity);
4311 }
4313 /* If there was no specified Interface_Name and the external and
4314 internal names of the subprogram are the same, only use the
4315 internal name to allow disambiguation of nested subprograms. */
4320 /* If we are defining the subprogram and it has an Address clause
4321 we must get the address expression from the saved GCC tree for the
4322 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4323 the address expression here since the front-end has guaranteed
4324 in that case that the elaboration has no effects. If there is
4325 an Address clause and we are not defining the object, just
4326 make it a constant. */
4328 {
4332 gnu_address
4339 /* Convert the type of the object to a reference type that can
4340 alias everything as per 13.3(19). */
4341 gnu_type
4346 gnu_decl
4351 }
4357 else
4358 {
4360 {
4364 }
4370 gnat_entity);
4372 {
4373 tree gnu_stub_decl
4378 gnat_entity);
4380 }
4382 /* This is unrelated to the stub built right above. */
4385 }
4386 }
4397 {
4398 /* Get the "full view" of this entity. If this is an incomplete
4399 entity from a limited with, treat its non-limited view as the
4400 full view. Otherwise, use either the full view or the underlying
4401 full view, whichever is present. This is used in all the tests
4402 below. */
4403 Entity_Id full_view
4410 /* If this is an incomplete type with no full view, it must be a Taft
4411 Amendment type, in which case we return a dummy type. Otherwise,
4412 just get the type from its Etype. */
4414 {
4416 {
4419 }
4420 else
4421 {
4425 }
4427 }
4429 /* If we already made a type for the full view, reuse it. */
4431 {
4434 }
4436 /* Otherwise, if we are not defining the type now, get the type
4437 from the full view. But always get the type from the full view
4438 for define on use types, since otherwise we won't see them! */
4444 {
4448 }
4450 /* For incomplete types, make a dummy type entry which will be
4451 replaced later. Save it as the full declaration's type so
4452 we can do any needed updates when we see it. */
4457 }
4460 /* Class-wide types are always transformed into their root type. */
4469 /* Concurrent types are always transformed into their record type. */
4472 else
4483 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4484 we've already saved it, so we don't try to. */
4491 }
4493 /* If we had a case where we evaluated another type and it might have
4494 defined this one, handle it here. */
4496 {
4499 }
4501 /* If we are processing a type and there is either no decl for it or
4502 we just made one, do some common processing for the type, such as
4503 handling alignment and possible padding. */
4505 {
4506 /* Tell the middle-end that objects of tagged types are guaranteed to
4507 be properly aligned. This is necessary because conversions to the
4508 class-wide type are translated into conversions to the root type,
4509 which can be less aligned than some of its derived types. */
4514 /* If the type is passed by reference, objects of this type must be
4515 fully addressable and cannot be copied. */
4519 /* ??? Don't set the size for a String_Literal since it is either
4520 confirming or we don't handle it properly (if the low bound is
4521 non-constant). */
4527 /* If a size was specified, see if we can make a new type of that size
4528 by rearranging the type, for example from a fat to a thin pointer. */
4530 {
4531 gnu_type
4538 }
4540 /* If the alignment hasn't already been processed and this is
4541 not an unconstrained array, see if an alignment is specified.
4542 If not, we pick a default alignment for atomic objects. */
4544 ;
4546 {
4550 /* Warn on suspiciously large alignments. This should catch
4551 errors about the (alignment,byte)/(size,bit) discrepancy. */
4553 {
4554 tree size;
4556 /* If a size was specified, take it into account. Otherwise
4557 use the RM size for records as the type size has already
4558 been adjusted to the alignment. */
4566 else
4569 /* Consider an alignment as suspicious if the alignment/size
4570 ratio is greater or equal to the byte/bit ratio. */
4575 gnat_entity);
4576 }
4577 }
4588 /* See if we need to pad the type. If we did, and made a record,
4589 the name of the new type may be changed. So get it back for
4590 us when we make the new TYPE_DECL below. */
4596 {
4600 }
4604 /* If we are at global level, GCC will have applied variable_size to
4605 the type, but that won't have done anything. So, if it's not
4606 a constant or self-referential, call elaborate_expression_1 to
4607 make a variable for the size rather than calculating it each time.
4608 Handle both the RM size and the actual size. */
4613 {
4621 /* ??? For now, store the size as a multiple of the alignment in
4622 bytes so that we can see the alignment from the tree. */
4629 /* ??? gnu_type may come from an existing type so the MULT_EXPR node
4630 may not be marked by the call to create_type_decl below. */
4634 {
4639 {
4643 /* If the position of the variant part is constant, subtract
4644 it from the size of the type of the parent to get the new
4645 size. This manual CSE reduces the data size. */
4647 {
4655 }
4656 else
4657 {
4660 gnat_entity,
4664 /* ??? For now, store the size as a multiple of the
4665 alignment in bytes so that we can see the alignment
4666 from the tree. */
4669 gnat_entity,
4670 get_identifier
4675 /* ??? For now, store the offset as a multiple of the
4676 alignment in bytes so that we can see the alignment
4677 from the tree. */
4680 gnat_entity,
4683 DECL_OFFSET_ALIGN
4685 }
4689 }
4693 else
4694 ada_size
4699 }
4700 }
4702 /* If this is a record type or subtype, call elaborate_expression_1 on
4703 any field position. Do this for both global and local types.
4704 Skip any fields that we haven't made trees for to avoid problems with
4705 class wide types. */
4710 {
4713 /* ??? For now, store the offset as a multiple of the alignment
4714 in bytes so that we can see the alignment from the tree. */
4716 {
4719 gnat_temp,
4724 /* ??? The context of gnu_field is not necessarily gnu_type
4725 so the MULT_EXPR node built above may not be marked by
4726 the call to create_type_decl below. */
4729 }
4730 }
4733 gnu_type
4750 else
4751 {
4754 }
4755 }
4758 {
4761 /* If this is a derived type, relate its alias set to that of its parent
4762 to avoid troubles when a call to an inherited primitive is inlined in
4763 a context where a derived object is accessed. The inlined code works
4764 on the parent view so the resulting code may access the same object
4765 using both the parent and the derived alias sets, which thus have to
4766 conflict. As the same issue arises with component references, the
4767 parent alias set also has to conflict with composite types enclosing
4768 derived components. For instance, if we have:
4770 type D is new T;
4771 type R is record
4772 Component : D;
4773 end record;
4775 we want T to conflict with both D and R, in addition to R being a
4776 superset of D by record/component construction.
4778 One way to achieve this is to perform an alias set copy from the
4779 parent to the derived type. This is not quite appropriate, though,
4780 as we don't want separate derived types to conflict with each other:
4782 type I1 is new Integer;
4783 type I2 is new Integer;
4785 We want I1 and I2 to both conflict with Integer but we do not want
4786 I1 to conflict with I2, and an alias set copy on derivation would
4787 have that effect.
4789 The option chosen is to make the alias set of the derived type a
4790 superset of that of its parent type. It trivially fulfills the
4791 simple requirement for the Integer derivation example above, and
4792 the component case as well by superset transitivity:
4794 superset superset
4795 R ----------> D ----------> T
4797 However, for composite types, conversions between derived types are
4798 translated into VIEW_CONVERT_EXPRs so a sequence like:
4800 type Comp1 is new Comp;
4801 type Comp2 is new Comp;
4802 procedure Proc (C : Comp1);
4804 C : Comp2;
4805 Proc (Comp1 (C));
4807 is translated into:
4809 C : Comp2;
4810 Proc ((Comp1 &) &VIEW_CONVERT_EXPR <Comp1> (C));
4812 and gimplified into:
4814 C : Comp2;
4815 Comp1 *C.0;
4816 C.0 = (Comp1 *) &C;
4817 Proc (C.0);
4819 i.e. generates code involving type punning. Therefore, Comp1 needs
4820 to conflict with Comp2 and an alias set copy is required.
4822 The language rules ensure the parent type is already frozen here. */
4824 {
4829 }
4831 /* Back-annotate the Alignment of the type if not already in the
4832 tree. Likewise for sizes. */
4834 {
4838 /* If the default alignment of "double" or larger scalar types is
4839 specifically capped and this is not an array with an alignment
4840 clause on the component type, return the cap. */
4842 is_capped_double
4845 is_capped_double
4847 else
4852 else
4856 }
4859 {
4862 /* If the size is self-referential, annotate the maximum value. */
4867 {
4868 /* In this mode, the tag and the parent components are not
4869 generated by the front-end so the sizes must be adjusted. */
4871 Uint uint_size;
4874 {
4876 bitsizetype);
4879 }
4880 else
4886 gnu_size,
4887 pointer_size));
4891 }
4892 else
4894 }
4898 }
4908 /* If we haven't already, associate the ..._DECL node that we just made with
4909 the input GNAT entity node. */
4913 /* If this is an enumeration or floating-point type, we were not able to set
4914 the bounds since they refer to the type. These are always static. */
4917 {
4921 /* If this is a padded type, we need to use the underlying type. */
4925 /* If this is a floating point type and we haven't set a floating
4926 point type yet, use this in the evaluation of the bounds. */
4934 {
4935 /* Enumeration types have specific RM bounds. */
4939 /* Write full debugging information. Since this has both a
4940 typedef and a tag, avoid outputting the name twice. */
4943 }
4945 else
4946 {
4947 /* Floating-point types don't have specific RM bounds. */
4950 }
4951 }
4953 /* If we deferred processing of incomplete types, re-enable it. If there
4954 were no other disables and we have some to process, do so. */
4956 {
4958 {
4961 /* We are back to level 0 for the deferring of incomplete types.
4962 But processing these incomplete types below may itself require
4963 deferring, so preserve what we have and restart from scratch. */
4967 /* For finalization, however, all types must be complete so we
4968 cannot do the same because deferred incomplete types may end up
4969 referencing each other. Process them all recursively first. */
4970 defer_finalize_level++;
4973 {
4980 }
4982 defer_finalize_level--;
4983 }
4985 /* All the deferred incomplete types have been processed so we can
4986 now proceed with the finalization of the deferred types. */
4988 {
4990 tree t;
4996 }
4997 }
4999 /* If we are not defining this type, see if it's in the incomplete list.
5000 If so, handle that list entry now. */
5002 {
5007 {
5011 }
5012 }
5015 force_global--;
5017 /* If this is a packed array type whose original array type is itself
5018 an Itype without freeze node, make sure the latter is processed. */
5026 }
5028 /* Similar, but if the returned value is a COMPONENT_REF, return the
5029 FIELD_DECL. */
5031 tree
5033 {
5040 }
5042 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5043 the GCC type corresponding to that entity. */
5045 tree
5047 {
5048 tree gnu_decl;
5050 /* The back end never attempts to annotate generic types. */
5058 }
5060 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5061 the unpadded version of the GCC type corresponding to that entity. */
5063 tree
5065 {
5072 }
5073 \f
5074 /* Wrap up compilation of DECL, a TYPE_DECL, possibly deferring it.
5075 Every TYPE_DECL generated for a type definition must be passed
5076 to this function once everything else has been done for it. */
5078 void
5080 {
5081 /* We need to defer finalizing the type if incomplete types
5082 are being deferred or if they are being processed. */
5085 else
5087 }
5089 /* Same as above but without deferring the compilation. This
5090 function should not be invoked directly on a TYPE_DECL. */
5092 static void
5094 {
5100 /* Now process all the variants. This is needed for STABS. */
5102 {
5110 }
5111 }
5113 /* Finalize any From_With_Type incomplete types. We do this after processing
5114 our compilation unit and after processing its spec, if this is a body. */
5116 void
5118 {
5124 {
5131 }
5132 }
5134 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
5135 kind of type (such E_Task_Type) that has a different type which Gigi
5136 uses for its representation. If the type does not have a special type
5137 for its representation, return GNAT_ENTITY. If a type is supposed to
5138 exist, but does not, abort unless annotating types, in which case
5139 return Empty. If GNAT_ENTITY is Empty, return Empty. */
5141 Entity_Id
5143 {
5150 {
5174 }
5178 }
5180 /* Return a GCC tree for a type corresponding to the component type of the
5181 array type or subtype GNAT_ARRAY. DEFINITION is true if this component
5182 is for an array being defined. DEBUG_INFO_P is true if we need to write
5183 debug information for other types that we may create in the process. */
5185 static tree
5188 {
5190 tree gnu_comp_size;
5192 /* Try to get a smaller form of the component if needed. */
5206 /* Get and validate any specified Component_Size. */
5207 gnu_comp_size
5212 /* If the array has aliased components and the component size can be zero,
5213 force at least unit size to ensure that the components have distinct
5214 addresses. */
5220 gnu_comp_size
5223 /* If the component type is a RECORD_TYPE that has a self-referential size,
5224 then use the maximum size for the component size. */
5230 /* Honor the component size. This is not needed for bit-packed arrays. */
5232 {
5236 /* If an alignment is specified, use it as a cap on the component type
5237 so that it can be honored for the whole type. But ignore it for the
5238 original type of packed array types. */
5241 else
5247 else
5253 /* If a padding record was made, declare it now since it will never be
5254 declared otherwise. This is necessary to ensure that its subtrees
5255 are properly marked. */
5259 }
5262 gnu_type
5267 }
5269 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
5270 using MECH as its passing mechanism, to be placed in the parameter
5271 list built for GNAT_SUBPROG. Assume a foreign convention for the
5272 latter if FOREIGN is true. Also set CICO to true if the parameter
5273 must use the copy-in copy-out implementation mechanism.
5275 The returned tree is a PARM_DECL, except for those cases where no
5276 parameter needs to be actually passed to the subprogram; the type
5277 of this "shadow" parameter is then returned instead. */
5279 static tree
5282 {
5287 /* The parameter can be indirectly modified if its address is taken. */
5291 tree gnu_param;
5293 /* Copy-return is used only for the first parameter of a valued procedure.
5294 It's a copy mechanism for which a parameter is never allocated. */
5296 {
5300 }
5302 /* If this is either a foreign function or if the underlying type won't
5303 be passed by reference, strip off possible padding type. */
5305 {
5309 || foreign
5313 }
5315 /* If this is a read-only parameter, make a variant of the type that is
5316 read-only. ??? However, if this is an unconstrained array, that type
5317 can be very complex, so skip it for now. Likewise for any other
5318 self-referential type. */
5326 /* For foreign conventions, pass arrays as pointers to the element type.
5327 First check for unconstrained array and get the underlying array. */
5329 gnu_param_type
5332 /* For GCC builtins, pass Address integer types as (void *) */
5338 /* VMS descriptors are themselves passed by reference. */
5341 gnu_param_type
5344 gnat_subprog));
5346 {
5347 /* Build both a 32-bit and 64-bit descriptor, one of which will be
5348 chosen in fill_vms_descriptor. */
5349 gnu_param_type_alt
5352 gnat_subprog));
5353 gnu_param_type
5356 gnat_subprog));
5357 }
5359 /* Arrays are passed as pointers to element type for foreign conventions. */
5363 {
5364 /* Strip off any multi-dimensional entries, then strip
5365 off the last array to get the component type. */
5379 }
5381 /* Fat pointers are passed as thin pointers for foreign conventions. */
5383 gnu_param_type
5386 /* If we must pass or were requested to pass by reference, do so.
5387 If we were requested to pass by copy, do so.
5388 Otherwise, for foreign conventions, pass In Out or Out parameters
5389 or aggregates by reference. For COBOL and Fortran, pass all
5390 integer and FP types that way too. For Convention Ada, use
5391 the standard Ada default. */
5395 && ((foreign
5397 || (foreign
5402 || (!foreign
5404 {
5408 /* In some ABIs, e.g. SPARC 32-bit, fat pointer types are themselves
5409 passed by reference. Pass them by explicit reference, this will
5410 generate more debuggable code at -O0. */
5414 gnu_param_type,
5416 {
5419 }
5420 }
5422 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
5429 /* If this is an Out parameter that isn't passed by reference and isn't
5430 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
5431 it will be a VAR_DECL created when we process the procedure, so just
5432 return its type. For the special parameter of a valued procedure,
5433 never pass it in.
5435 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
5436 Out parameters with discriminants or implicit initial values to be
5437 handled like In Out parameters. These type are normally built as
5438 aggregates, hence passed by reference, except for some packed arrays
5439 which end up encoded in special integer types.
5441 The exception we need to make is then for packed arrays of records
5442 with discriminants or implicit initial values. We have no light/easy
5443 way to check for the latter case, so we merely check for packed arrays
5444 of records. This may lead to useless copy-in operations, but in very
5445 rare cases only, as these would be exceptions in a set of already
5446 exceptional situations. */
5448 && !by_ref
5449 && (by_return
5469 /* Save the alternate descriptor type, if any. */
5473 /* If no Mechanism was specified, indicate what we're using, then
5474 back-annotate it. */
5480 }
5482 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
5484 static bool
5486 {
5493 return
5495 }
5497 /* Return true if the array type GNU_TYPE, which represents a dimension of
5498 GNAT_TYPE, has a non-aliased component in the back-end sense. */
5500 static bool
5502 {
5503 /* If the array type is not the innermost dimension of the GNAT type,
5504 then it has a non-aliased component. */
5509 /* If the array type has an aliased component in the front-end sense,
5510 then it also has an aliased component in the back-end sense. */
5514 /* If this is a derived type, then it has a non-aliased component if
5515 and only if its parent type also has one. */
5517 {
5521 gnu_parent_type
5526 }
5528 /* Otherwise, rely exclusively on properties of the element type. */
5530 }
5532 /* Return true if GNAT_ADDRESS is a value known at compile-time. */
5534 static bool
5536 {
5537 /* Catch System'To_Address. */
5542 }
5544 /* Return true if GNAT_RANGE, a N_Range node, cannot be superflat, i.e. if the
5545 inequality HB >= LB-1 is true. LB and HB are the low and high bounds. */
5547 static bool
5549 {
5551 Node_Id scalar_range;
5554 /* If the low bound is not constant, try to find an upper bound. */
5563 /* If the high bound is not constant, try to find a lower bound. */
5572 /* If we have failed to find constant bounds, punt. */
5577 /* We need at least a signed 64-bit type to catch most cases. */
5583 /* If the low bound is the smallest integer, nothing can be smaller. */
5589 }
5591 /* Return true if GNU_EXPR is (essentially) the address of a CONSTRUCTOR. */
5593 static bool
5595 {
5603 }
5604 \f
5605 /* Given GNAT_ENTITY, elaborate all expressions that are required to
5606 be elaborated at the point of its definition, but do nothing else. */
5608 void
5610 {
5612 {
5619 {
5623 /* ??? Tests to avoid Constraint_Error in static expressions
5624 are needed until after the front stops generating bogus
5625 conversions on bounds of real types. */
5633 }
5636 {
5640 /* If this is a record extension, go a level further to find the
5641 record definition. */
5644 }
5654 {
5655 Node_Id gnat_discriminant_expr;
5656 Entity_Id gnat_field;
5660 gnat_discriminant_expr
5665 /* ??? For now, ignore access discriminants. */
5670 }
5673 }
5674 }
5675 \f
5676 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
5677 any entities on its entity chain similarly. */
5679 void
5681 {
5682 Entity_Id gnat_sub_entity;
5685 /* If this has an entity list, process all in the list. */
5702 /* Now clear this if it has been defined, but only do so if it isn't
5703 a subprogram or parameter. We could refine this, but it isn't
5704 worth it. If this is statically allocated, it is supposed to
5705 hang around out of cope. */
5708 {
5711 }
5712 }
5713 \f
5714 /* Relate the alias sets of GNU_NEW_TYPE and GNU_OLD_TYPE according to OP.
5715 If this is a multi-dimensional array type, do this recursively.
5717 OP may be
5718 - ALIAS_SET_COPY: the new set is made a copy of the old one.
5719 - ALIAS_SET_SUPERSET: the new set is made a superset of the old one.
5720 - ALIAS_SET_SUBSET: the new set is made a subset of the old one. */
5722 static void
5724 {
5725 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
5726 of a one-dimensional array, since the padding has the same alias set
5727 as the field type, but if it's a multi-dimensional array, we need to
5728 see the inner types. */
5734 /* Unconstrained array types are deemed incomplete and would thus be given
5735 alias set 0. Retrieve the underlying array type. */
5737 gnu_old_type
5740 gnu_new_type
5749 {
5751 /* The alias set shouldn't be copied between array types with different
5752 aliasing settings because this can break the aliasing relationship
5753 between the array type and its element type. */
5754 #ifndef ENABLE_CHECKING
5756 #endif
5767 {
5771 /* Do nothing if the alias sets conflict. This ensures that we
5772 never call record_alias_subset several times for the same pair
5773 or at all for alias set 0. */
5775 {
5778 else
5780 }
5781 }
5786 }
5789 }
5790 \f
5791 /* Return true if the size represented by GNU_SIZE can be handled by an
5792 allocation. If STATIC_P is true, consider only what can be done with a
5793 static allocation. */
5795 static bool
5797 {
5798 HOST_WIDE_INT our_size;
5800 /* If this is not a static allocation, the only case we want to forbid
5801 is an overflowing size. That will be converted into a raise a
5802 Storage_Error. */
5807 /* Otherwise, we need to deal with both variable sizes and constant
5808 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
5809 since assemblers may not like very large sizes. */
5815 }
5816 \f
5817 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
5818 NAME, ARGS and ERROR_POINT. */
5820 static void
5823 tree attr_name,
5824 tree attr_args,
5825 Node_Id attr_error_point)
5826 {
5836 }
5838 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
5840 static void
5842 {
5843 Node_Id gnat_temp;
5845 /* Attributes are stored as Representation Item pragmas. */
5850 {
5855 /* Map the kind of pragma at hand. Skip if this is not one
5856 we know how to handle. */
5859 {
5890 }
5892 /* See what arguments we have and turn them into GCC trees for
5893 attribute handlers. These expect identifier for strings. We
5894 handle at most two arguments, static expressions only. */
5897 {
5903 {
5910 }
5914 {
5919 }
5920 }
5922 /* Prepend to the list now. Make a list of the argument we might
5923 have, as GCC expects it. */
5924 prepend_one_attribute_to
5931 }
5932 }
5933 \f
5934 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
5935 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
5936 return the GCC tree to use for that expression. GNU_NAME is the suffix
5937 to use if a variable needs to be created and DEFINITION is true if this
5938 is a definition of GNAT_ENTITY. If NEED_VALUE is true, we need a result;
5939 otherwise, we are just elaborating the expression for side-effects. If
5940 NEED_DEBUG is true, we need a variable for debugging purposes even if it
5941 isn't needed for code generation. */
5943 static tree
5946 {
5947 tree gnu_expr;
5949 /* If we already elaborated this expression (e.g. it was involved
5950 in the definition of a private type), use the old value. */
5954 /* If we don't need a value and this is static or a discriminant,
5955 we don't need to do anything. */
5962 /* If it's a static expression, we don't need a variable for debugging. */
5966 /* Otherwise, convert this tree to its GCC equivalent and elaborate it. */
5970 /* Save the expression in case we try to elaborate this entity again. Since
5971 it's not a DECL, don't check it. Don't save if it's a discriminant. */
5976 }
5978 /* Similar, but take a GNU expression and always return a result. */
5980 static tree
5983 {
5984 /* Skip any conversions and simple arithmetics to see if the expression
5985 is a read-only variable.
5986 ??? This really should remain read-only, but we have to think about
5987 the typing of the tree here. */
5988 tree gnu_inner_expr
5994 /* In most cases, we won't see a naked FIELD_DECL because a discriminant
5995 reference will have been replaced with a COMPONENT_REF when the type
5996 is being elaborated. However, there are some cases involving child
5997 types where we will. So convert it to a COMPONENT_REF. We hope it
5998 will be at the highest level of the expression in these cases. */
6004 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
6005 that is read-only, make a variable that is initialized to contain the
6006 bound when the package containing the definition is elaborated. If
6007 this entity is defined at top level and a bound or discriminant value
6008 isn't a constant or a reference to a discriminant, replace the bound
6009 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
6010 rely here on the fact that an expression cannot contain both the
6011 discriminant and some other variable. */
6018 /* If GNU_EXPR contains a discriminant, we can't elaborate a variable. */
6022 /* Now create the variable if we need it. */
6024 gnu_decl
6031 /* We only need to use this variable if we are in global context since GCC
6032 can do the right thing in the local case. */
6037 }
6039 /* Similar, but take an alignment factor and make it explicit in the tree. */
6041 static tree
6044 {
6046 return
6049 gnu_expr,
6050 unit_align),
6052 need_debug),
6053 unit_align);
6054 }
6055 \f
6056 /* Create a record type that contains a SIZE bytes long field of TYPE with a
6057 starting bit position so that it is aligned to ALIGN bits, and leaving at
6058 least ROOM bytes free before the field. BASE_ALIGN is the alignment the
6059 record is guaranteed to get. */
6061 tree
6064 {
6065 /* We will be crafting a record type with one field at a position set to be
6066 the next multiple of ALIGN past record'address + room bytes. We use a
6067 record placeholder to express record'address. */
6071 tree record_addr_st
6074 /* The diagram below summarizes the shape of what we manipulate:
6076 <--------- pos ---------->
6077 { +------------+-------------+-----------------+
6078 record =>{ |############| ... | field (type) |
6079 { +------------+-------------+-----------------+
6080 |<-- room -->|<- voffset ->|<---- size ----->|
6081 o o
6082 | |
6083 record_addr vblock_addr
6085 Every length is in sizetype bytes there, except "pos" which has to be
6086 set as a bit position in the GCC tree for the record. */
6098 /* Compute VOFFSET and then POS. The next byte position multiple of some
6099 alignment after some address is obtained by "and"ing the alignment minus
6100 1 with the two's complement of the address. */
6105 /* POS = (ROOM + VOFFSET) * BIT_PER_UNIT, in bitsizetype. */
6109 bitsize_unit_node);
6111 /* Craft the GCC record representation. We exceptionally do everything
6112 manually here because 1) our generic circuitry is not quite ready to
6113 handle the complex position/size expressions we are setting up, 2) we
6114 have a strong simplifying factor at hand: we know the maximum possible
6115 value of voffset, and 3) we have to set/reset at least the sizes in
6116 accordance with this maximum value anyway, as we need them to convey
6117 what should be "alloc"ated for this type.
6119 Use -1 as the 'addressable' indication for the field to prevent the
6120 creation of a bitfield. We don't need one, it would have damaging
6121 consequences on the alignment computation, and create_field_decl would
6122 make one without this special argument, for instance because of the
6123 complex position expression. */
6134 bitsize_unit_node),
6143 /* Declare it now since it will never be declared otherwise. This is
6144 necessary to ensure that its subtrees are properly marked. */
6148 }
6149 \f
6150 /* Return the result of rounding T up to ALIGN. */
6154 {
6159 }
6161 /* TYPE is a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE that is being used
6162 as the field type of a packed record if IN_RECORD is true, or as the
6163 component type of a packed array if IN_RECORD is false. See if we can
6164 rewrite it either as a type that has a non-BLKmode, which we can pack
6165 tighter in the packed record case, or as a smaller type. If so, return
6166 the new type. If not, return the original type. */
6168 static tree
6170 {
6175 /* No point in doing anything if the size is zero. */
6181 /* Copy the name and flags from the old type to that of the new.
6182 Note that we rely on the pointer equality created here for
6183 TYPE_NAME to look through conversions in various places. */
6190 /* If we are in a record and have a small size, set the alignment to
6191 try for an integral mode. Otherwise set it to try for a smaller
6192 type with BLKmode. */
6194 {
6197 }
6198 else
6199 {
6202 /* Do not try to shrink the size if the RM size is not constant. */
6207 /* Round the RM size up to a unit boundary to get the minimal size
6208 for a BLKmode record. Give up if it's already the size. */
6216 }
6220 /* Now copy the fields, keeping the position and size as we don't want
6221 to change the layout by propagating the packedness downwards. */
6224 {
6235 /* However, for the last field in a not already packed record type
6236 that is of an aggregate type, we need to use the RM size in the
6237 packable version of the record type, see finish_record_type. */
6247 else
6250 new_field
6263 }
6268 /* If this is a padding record, we never want to make the size smaller
6269 than what was specified. For QUAL_UNION_TYPE, also copy the size. */
6271 {
6275 }
6276 else
6277 {
6281 }
6288 /* Try harder to get a packable type if necessary, for example
6289 in case the record itself contains a BLKmode field. */
6294 /* If neither the mode nor the size has shrunk, return the old type. */
6299 }
6300 \f
6301 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
6302 if needed. We have already verified that SIZE and TYPE are large enough.
6303 GNAT_ENTITY is used to name the resulting record and to issue a warning.
6304 IS_COMPONENT_TYPE is true if this is being done for the component type
6305 of an array. IS_USER_TYPE is true if we must complete the original type.
6306 DEFINITION is true if this type is being defined. SAME_RM_SIZE is true
6307 if the RM size of the resulting type is to be set to SIZE too; otherwise,
6308 it's set to the RM size of the original type. */
6310 tree
6314 {
6319 /* If TYPE is a padded type, see if it agrees with any size and alignment
6320 we were given. If so, return the original type. Otherwise, strip
6321 off the padding, since we will either be returning the inner type
6322 or repadding it. If no size or alignment is specified, use that of
6323 the original padded type. */
6325 {
6342 }
6344 /* If the size is either not being changed or is being made smaller (which
6345 is not done here and is only valid for bitfields anyway), show the size
6346 isn't changing. Likewise, clear the alignment if it isn't being
6347 changed. Then return if we aren't doing anything. */
6360 /* If requested, complete the original type and give it a name. */
6367 gnat_entity);
6369 /* We used to modify the record in place in some cases, but that could
6370 generate incorrect debugging information. So make a new record
6371 type and name. */
6386 bitsize_unit_node));
6388 /* If we are changing the alignment and the input type is a record with
6389 BLKmode and a small constant size, try to make a form that has an
6390 integral mode. This might allow the padding record to also have an
6391 integral mode, which will be much more efficient. There is no point
6392 in doing so if a size is specified unless it is also a small constant
6393 size and it is incorrect to do so if we cannot guarantee that the mode
6394 will be naturally aligned since the field must always be addressable.
6396 ??? This might not always be a win when done for a stand-alone object:
6397 since the nominal and the effective type of the object will now have
6398 different modes, a VIEW_CONVERT_EXPR will be required for converting
6399 between them and it might be hard to overcome afterwards, including
6400 at the RTL level when the stand-alone object is accessed as a whole. */
6407 && (!size
6410 {
6415 }
6417 /* Now create the field with the original size. */
6422 /* Do not emit debug info until after the auxiliary record is built. */
6425 /* Set the same size for its RM size if requested; otherwise reuse
6426 the RM size of the original type. */
6429 /* Unless debugging information isn't being written for the input type,
6430 write a record that shows what we are a subtype of and also make a
6431 variable that indicates our size, if still variable. */
6437 {
6463 }
6467 /* If the size was widened explicitly, maybe give a warning. Take the
6468 original size as the maximum size of the input if there was an
6469 unconstrained record involved and round it up to the specified alignment,
6470 if one was specified. */
6478 && size
6487 {
6500 /* Generate message only for entities that come from source, since
6501 if we have an entity created by expansion, the message will be
6502 generated for some other corresponding source entity. */
6504 {
6513 }
6514 }
6517 }
6518 \f
6519 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
6520 the value passed against the list of choices. */
6522 tree
6524 {
6525 Node_Id choice;
6526 Node_Id gnat_temp;
6531 {
6533 {
6538 this_test
6552 this_test
6562 /* This represents either a subtype range, an enumeration
6563 literal, or a constant Ekind says which. If an enumeration
6564 literal or constant, fall through to the next case. */
6567 {
6573 this_test
6580 }
6582 /* ... fall through ... */
6588 single);
6597 }
6600 this_test);
6601 }
6604 }
6605 \f
6606 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
6607 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
6609 static int
6611 {
6612 /* If the field contains an item of variable size, we cannot pack it
6613 because we cannot create temporaries of non-fixed size in case
6614 we need to take the address of the field. See addressable_p and
6615 the notes on the addressability issues for further details. */
6619 /* If the alignment of the record is specified and the field type
6620 is over-aligned, request Storage_Unit alignment for the field. */
6622 {
6625 else
6627 }
6630 }
6632 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
6633 placed in GNU_RECORD_TYPE.
6635 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
6636 record has Component_Alignment of Storage_Unit, -2 if the enclosing
6637 record has a specified alignment.
6639 DEFINITION is true if this field is for a record being defined.
6641 DEBUG_INFO_P is true if we need to write debug information for types
6642 that we may create in the process. */
6644 static tree
6647 {
6651 bool needs_strict_alignment
6655 /* If this field requires strict alignment, we cannot pack it because
6656 it would very likely be under-aligned in the record. */
6659 else
6662 /* If a size is specified, use it. Otherwise, if the record type is packed,
6663 use the official RM size. See "Handling of Type'Size Values" in Einfo
6664 for further details. */
6671 else
6674 /* If we have a specified size that is smaller than that of the field's type,
6675 or a position is specified, and the field's type is a record that doesn't
6676 require strict alignment, see if we can get either an integral mode form
6677 of the type or a smaller form. If we can, show a size was specified for
6678 the field if there wasn't one already, so we know to make this a bitfield
6679 and avoid making things wider.
6681 Changing to an integral mode form is useful when the record is packed as
6682 we can then place the field at a non-byte-aligned position and so achieve
6683 tighter packing. This is in addition required if the field shares a byte
6684 with another field and the front-end lets the back-end handle the access
6685 to the field, because GCC cannot handle non-byte-aligned BLKmode fields.
6687 Changing to a smaller form is required if the specified size is smaller
6688 than that of the field's type and the type contains sub-fields that are
6689 padded, in order to avoid generating accesses to these sub-fields that
6690 are wider than the field.
6692 We avoid the transformation if it is not required or potentially useful,
6693 as it might entail an increase of the field's alignment and have ripple
6694 effects on the outer record type. A typical case is a field known to be
6695 byte-aligned and not to share a byte with another field. */
6701 || (gnu_size
6707 {
6710 {
6714 }
6715 }
6717 /* If we are packing the record and the field is BLKmode, round the
6718 size up to a byte boundary. */
6723 {
6724 Entity_Id gnat_parent
6731 /* Ensure the position does not overlap with the parent subtype, if there
6732 is one. This test is omitted if the parent of the tagged type has a
6733 full rep clause since, in this case, component clauses are allowed to
6734 overlay the space allocated for the parent type and the front-end has
6735 checked that there are no overlapping components. */
6737 {
6742 {
6743 post_error_ne_tree
6747 }
6748 }
6750 /* If this field needs strict alignment, ensure the record is
6751 sufficiently aligned and that that position and size are
6752 consistent with the alignment. */
6754 {
6760 {
6762 post_error_ne_tree
6768 post_error_ne_tree
6774 post_error_ne_tree
6780 }
6785 {
6787 post_error_ne_num
6793 post_error_ne_num
6799 post_error_ne_num
6804 else
6808 }
6809 }
6813 }
6815 /* If the record has rep clauses and this is the tag field, make a rep
6816 clause for it as well. */
6819 {
6822 }
6824 else
6827 /* We need to make the size the maximum for the type if it is
6828 self-referential and an unconstrained type. In that case, we can't
6829 pack the field since we can't make a copy to align it. */
6831 && !gnu_size
6834 {
6837 }
6839 /* If a size is specified, adjust the field's type to it. */
6841 {
6842 tree orig_field_type;
6844 /* If the field's type is justified modular, we would need to remove
6845 the wrapper to (better) meet the layout requirements. However we
6846 can do so only if the field is not aliased to preserve the unique
6847 layout and if the prescribed size is not greater than that of the
6848 packed array to preserve the justification. */
6856 gnu_field_type
6864 /* If a padding record was made, declare it now since it will never be
6865 declared otherwise. This is necessary to ensure that its subtrees
6866 are properly marked. */
6871 }
6873 /* Otherwise (or if there was an error), don't specify a position. */
6874 else
6880 /* Now create the decl for the field. */
6881 gnu_field
6892 }
6893 \f
6894 /* Return true if TYPE is a type with variable size, a padding type with a
6895 field of variable size or is a record that has a field such a field. */
6897 static bool
6899 {
6900 tree field;
6919 }
6920 \f
6921 /* qsort comparer for the bit positions of two record components. */
6923 static int
6925 {
6928 const int ret
6932 }
6934 /* Translate and chain the GNAT_COMPONENT_LIST to the GNU_FIELD_LIST, set
6935 the result as the field list of GNU_RECORD_TYPE and finish it up. When
6936 called from gnat_to_gnu_entity during the processing of a record type
6937 definition, the GCC node for the parent, if any, will be the single field
6938 of GNU_RECORD_TYPE and the GCC nodes for the discriminants will be on the
6939 GNU_FIELD_LIST. The other calls to this function are recursive calls for
6940 the component list of a variant and, in this case, GNU_FIELD_LIST is empty.
6942 PACKED is 1 if this is for a packed record, -1 if this is for a record
6943 with Component_Alignment of Storage_Unit, -2 if this is for a record
6944 with a specified alignment.
6946 DEFINITION is true if we are defining this record type.
6948 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
6949 with a rep clause is to be added; in this case, that is all that should
6950 be done with such fields.
6952 CANCEL_ALIGNMENT is true if the alignment should be zeroed before laying
6953 out the record. This means the alignment only serves to force fields to
6954 be bitfields, but not to require the record to be that aligned. This is
6955 used for variants.
6957 ALL_REP is true if a rep clause is present for all the fields.
6959 UNCHECKED_UNION is true if we are building this type for a record with a
6960 Pragma Unchecked_Union.
6962 DEBUG_INFO_P is true if we need to write debug information about the type.
6964 MAYBE_UNUSED is true if this type may be unused in the end; this doesn't
6965 mean that its contents may be unused as well, but only the container. */
6968 static void
6974 {
6981 /* For each component referenced in a component declaration create a GCC
6982 field and add it to the list, skipping pragmas in the GNAT list. */
6988 {
6992 /* If present, the _Parent field must have been created as the single
6993 field of the record type. Put it before any other fields. */
6995 {
6998 }
6999 else
7000 {
7004 /* If this is the _Tag field, put it before any other fields. */
7008 /* If this is the _Controller field, put it before the other
7009 fields except for the _Tag or _Parent field. */
7011 {
7014 }
7016 /* If this is a regular field, put it after the other fields. */
7017 else
7018 {
7023 }
7024 }
7027 }
7029 /* At the end of the component list there may be a variant part. */
7032 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
7033 mutually exclusive and should go in the same memory. To do this we need
7034 to treat each variant as a record whose elements are created from the
7035 component list for the variant. So here we create the records from the
7036 lists for the variants and put them all into the QUAL_UNION_TYPE.
7037 If this is an Unchecked_Union, we make a UNION_TYPE instead or
7038 use GNU_RECORD_TYPE if there are no fields so far. */
7040 {
7044 tree gnu_var_name
7053 gnu_union_name
7056 /* Reuse an enclosing union if all fields are in the variant part
7057 and there is no representation clause on the record, to match
7058 the layout of C unions. There is an associated check below. */
7063 else
7064 {
7065 gnu_union_type
7071 }
7076 {
7078 tree gnu_inner_name;
7079 tree gnu_qual;
7087 /* Set the alignment of the inner type in case we need to make
7088 inner objects into bitfields, but then clear it out so the
7089 record actually gets only the alignment required. */
7093 /* Similarly, if the outer record has a size specified and all
7094 fields have record rep clauses, we can propagate the size
7095 into the variant part. */
7097 {
7101 }
7103 /* Add the fields into the record type for the variant. Note that
7104 we aren't sure to really use it at this point, see below. */
7114 /* If this is an Unchecked_Union and we have exactly one field,
7115 use this field directly to match the layout of C unions. */
7120 else
7121 {
7122 /* Deal with packedness like in gnat_to_gnu_field. */
7123 int field_packed
7126 /* Finalize the record type now. We used to throw away
7127 empty records but we no longer do that because we need
7128 them to generate complete debug info for the variant;
7129 otherwise, the union type definition will be lacking
7130 the fields associated with these empty variants. */
7135 gnu_field
7137 gnu_union_type,
7138 all_rep_and_size
7140 all_rep_and_size
7148 }
7152 }
7154 /* Only make the QUAL_UNION_TYPE if there are non-empty variants. */
7156 {
7160 {
7164 }
7169 /* If GNU_UNION_TYPE is our record type, it means we must have an
7170 Unchecked_Union with no fields. Verify that and, if so, just
7171 return. */
7173 {
7175 && !gnu_field_list
7178 }
7183 /* Deal with packedness like in gnat_to_gnu_field. */
7184 union_field_packed
7187 gnu_union_field
7196 }
7197 }
7199 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
7200 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do
7201 this in a separate pass since we want to handle the discriminants but
7202 can't play with them until we've used them in debugging data above.
7204 ??? If we then reorder them, debugging information will be wrong but
7205 there's nothing that can be done about this at the moment. */
7208 {
7212 {
7215 else
7220 }
7221 else
7223 }
7225 /* If we have any fields in our rep'ed field list and it is not the case that
7226 all the fields in the record have rep clauses and P_REP_LIST is nonzero,
7227 set it and ignore these fields. */
7231 /* Otherwise, sort the fields by bit position and put them into their own
7232 record, before the others, if we also have fields without rep clauses. */
7234 {
7235 tree gnu_rep_type
7241 gnu_field;
7247 /* Put the fields in the list in order of increasing position, which
7248 means we start from the end. */
7251 {
7255 }
7258 {
7260 gnu_field
7265 }
7266 else
7267 {
7270 }
7271 }
7278 }
7279 \f
7280 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
7281 placed into an Esize, Component_Bit_Offset, or Component_Size value
7282 in the GNAT tree. */
7284 static Uint
7286 {
7287 TCode tcode;
7292 /* See if we've already saved the value for this node. */
7294 {
7305 }
7307 /* If we do not return inside this switch, TCODE will be set to the
7308 code to use for a Create_Node operand and LEN (set above) will be
7309 the number of recursive calls for us to make. */
7312 {
7317 /* This may come from a conversion from some smaller type, so ensure
7318 this is in bitsizetype. */
7321 /* For a negative value, build NEGATE_EXPR of the opposite. Such values
7322 appear in expressions containing aligning patterns. Note that, since
7323 sizetype is sign-extended but nonetheless unsigned, we don't directly
7324 use tree_int_cst_sgn. */
7326 {
7329 }
7334 /* The only case we handle here is a simple discriminant reference. */
7342 else
7348 /* Now just list the operations we handle. */
7379 {
7383 }
7385 /* Fall through... */
7389 }
7391 /* Now get each of the operands that's relevant for this code. If any
7392 cannot be expressed as a repinfo node, say we can't. */
7397 {
7401 }
7405 /* Save the result in the cache. */
7407 {
7411 }
7414 }
7416 /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
7417 and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
7418 size and alignment used by Gigi. Prefer SIZE over TYPE_SIZE if non-null.
7419 BY_REF is true if the object is used by reference and BY_DOUBLE_REF is
7420 true if the object is used by double reference. */
7422 void
7425 {
7427 {
7433 else
7435 }
7438 {
7447 }
7452 }
7454 /* Return first element of field list whose TREE_PURPOSE is the same as ELEM.
7455 Return NULL_TREE if there is no such element in the list. */
7457 static tree
7459 {
7461 {
7466 }
7468 }
7470 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding GCC type,
7471 set Component_Bit_Offset and Esize of the components to the position and
7472 size used by Gigi. */
7474 static void
7476 {
7477 Entity_Id gnat_field;
7478 tree gnu_list;
7480 /* We operate by first making a list of all fields and their position (we
7481 can get the size easily) and then update all the sizes in the tree. */
7482 gnu_list
7492 {
7494 gnu_list);
7496 {
7497 tree parent_offset;
7500 {
7501 /* In this mode the tag and parent components are not
7502 generated, so we add the appropriate offset to each
7503 component. For a component appearing in the current
7504 extension, the offset is the size of the parent. */
7507 parent_offset
7509 bitsizetype);
7510 else
7512 }
7513 else
7516 Set_Component_Bit_Offset
7518 annotate_value
7522 parent_offset)));
7526 }
7528 {
7529 /* If there is no entry, this is an inherited component whose
7530 position is the same as in the parent type. */
7531 Set_Component_Bit_Offset
7537 }
7538 }
7539 }
7540 \f
7541 /* Scan all fields in GNU_TYPE and return a TREE_LIST where TREE_PURPOSE is
7542 the FIELD_DECL and TREE_VALUE a TREE_VEC containing the byte position, the
7543 value to be placed into DECL_OFFSET_ALIGN and the bit position. The list
7544 of fields is flattened, except for variant parts if DO_NOT_FLATTEN_VARIANT
7545 is set to true. GNU_POS is to be added to the position, GNU_BITPOS to the
7546 bit position, OFFSET_ALIGN is the present offset alignment. GNU_LIST is a
7547 pre-existing list to be chained to the newly created entries. */
7549 static tree
7552 {
7553 tree gnu_field;
7556 gnu_field;
7558 {
7563 unsigned int our_offset_align
7572 /* Recurse on internal fields, flattening the nested fields except for
7573 those in the variant part, if requested. */
7575 {
7579 gnu_list
7583 else
7584 gnu_list
7588 }
7589 }
7592 }
7594 /* Return a VEC describing the substitutions needed to reflect the
7595 discriminant substitutions from GNAT_TYPE to GNAT_SUBTYPE. They can
7596 be in any order. The values in an element of the VEC are in the form
7597 of operands to SUBSTITUTE_IN_EXPR. DEFINITION is true if this is for
7598 a definition of GNAT_SUBTYPE. */
7602 {
7604 Entity_Id gnat_discrim;
7605 Node_Id gnat_value;
7612 /* Ignore access discriminants. */
7614 {
7617 elaborate_expression
7624 }
7627 }
7629 /* Scan all fields in QUAL_UNION_TYPE and return a VEC describing the
7630 variants of QUAL_UNION_TYPE that are still relevant after applying
7631 the substitutions described in SUBST_LIST. VARIANT_LIST is a
7632 pre-existing VEC onto which newly created entries should be
7633 pushed. */
7638 {
7639 tree gnu_field;
7642 gnu_field;
7644 {
7652 /* If the new qualifier is not unconditionally false, its variant may
7653 still be accessed. */
7655 {
7665 /* Recurse on the variant subpart of the variant, if any. */
7671 /* If the new qualifier is unconditionally true, the subsequent
7672 variants cannot be accessed. */
7675 }
7676 }
7679 }
7680 \f
7681 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
7682 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
7683 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
7684 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
7685 for the size of a field. COMPONENT_P is true if we are being called
7686 to process the Component_Size of GNAT_OBJECT. This is used for error
7687 message handling and to indicate to use the object size of GNU_TYPE.
7688 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
7689 it means that a size of zero should be treated as an unspecified size. */
7691 static tree
7694 {
7695 Node_Id gnat_error_node;
7698 /* Return 0 if no size was specified. */
7702 /* Ignore a negative size since that corresponds to our back-annotation. */
7706 /* Find the node to use for errors. */
7713 else
7716 /* Get the size as a tree. Issue an error if a size was specified but
7717 cannot be represented in sizetype. */
7720 {
7723 gnat_object);
7724 else
7726 gnat_object);
7728 }
7730 /* Ignore a zero size if it is not permitted. */
7734 /* The size of objects is always a multiple of a byte. */
7737 {
7741 else
7745 }
7747 /* If this is an integral type or a packed array type, the front-end has
7748 verified the size, so we need not do it here (which would entail
7749 checking against the bounds). However, if this is an aliased object,
7750 it may not be smaller than the type of the object. */
7755 /* If the object is a record that contains a template, add the size of
7756 the template to the specified size. */
7762 /* If a type needs strict alignment, a component of this type in
7763 a packed record cannot be packed and thus uses the type size. */
7766 else
7769 /* Modify the size of the type to be that of the maximum size if it has a
7770 discriminant. */
7774 /* If this is an access type or a fat pointer, the minimum size is that given
7775 by the smallest integral mode that's valid for pointers. */
7777 {
7782 }
7784 /* If the size of the object is a constant, the new size must not be
7785 smaller. */
7789 {
7791 post_error_ne_tree
7794 else
7795 post_error_ne_tree
7800 }
7803 }
7804 \f
7805 /* Similarly, but both validate and process a value of RM size. This
7806 routine is only called for types. */
7808 static void
7810 {
7811 Node_Id gnat_attr_node;
7814 /* Do nothing if no size was specified. */
7818 /* Ignore a negative size since that corresponds to our back-annotation. */
7822 /* Only issue an error if a Value_Size clause was explicitly given.
7823 Otherwise, we'd be duplicating an error on the Size clause. */
7824 gnat_attr_node
7827 /* Get the size as a tree. Issue an error if a size was specified but
7828 cannot be represented in sizetype. */
7831 {
7834 gnat_entity);
7836 }
7838 /* Ignore a zero size unless a Value_Size clause exists, or a size clause
7839 exists, or this is an integer type, in which case the front-end will
7840 have always set it. */
7849 /* If the old size is self-referential, get the maximum size. */
7853 /* If the size of the object is a constant, the new size must not be smaller
7854 (the front-end has verified this for scalar and packed array types). */
7862 && TYPE_PACKED_ARRAY_TYPE_P
7865 {
7867 post_error_ne_tree
7871 }
7873 /* Otherwise, set the RM size proper for integral types... */
7880 /* ...or the Ada size for record and union types. */
7886 }
7887 \f
7888 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
7889 If TYPE is the best type, return it. Otherwise, make a new type. We
7890 only support new integral and pointer types. FOR_BIASED is true if
7891 we are making a biased type. */
7893 static tree
7895 {
7898 tree new_type;
7900 /* If size indicates an error, just return TYPE to avoid propagating
7901 the error. Likewise if it's too large to represent. */
7908 {
7915 /* Integer types with precision 0 are forbidden. */
7919 /* Only do something if the type is not a packed array type and
7920 doesn't already have the proper size. */
7931 else
7940 /* Copy the name to show that it's essentially the same type and
7941 not a subrange type. */
7948 /* Do something if this is a fat pointer, in which case we
7949 may need to return the thin pointer. */
7951 {
7955 return
7956 build_pointer_type_for_mode
7959 }
7963 /* Only do something if this is a thin pointer, in which case we
7964 may need to return the fat pointer. */
7966 return
7972 }
7975 }
7976 \f
7977 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
7978 a type or object whose present alignment is ALIGN. If this alignment is
7979 valid, return it. Otherwise, give an error and return ALIGN. */
7981 static unsigned int
7983 {
7986 Node_Id gnat_error_node;
7988 /* Don't worry about checking alignment if alignment was not specified
7989 by the source program and we already posted an error for this entity. */
7993 /* Post the error on the alignment clause if any. Note, for the implicit
7994 base type of an array type, the alignment clause is on the first
7995 subtype. */
8003 gnat_error_node =
8006 else
8009 /* Within GCC, an alignment is an integer, so we must make sure a value is
8010 specified that fits in that range. Also, there is an upper bound to
8011 alignments we can support/allow. */
8019 {
8023 /* If the default alignment of "double" or larger scalar types is
8024 specifically capped and the new alignment is above the cap, do
8025 not post an error and change the alignment only if there is an
8026 alignment clause; this makes it possible to have the associated
8027 GCC type overaligned by default for performance reasons. */
8029 {
8030 Entity_Id gnat_type
8032 is_capped_double
8034 }
8036 {
8037 Entity_Id gnat_type
8039 is_capped_double
8041 }
8042 else
8046 {
8049 }
8050 else
8051 {
8058 }
8059 }
8060 else
8061 {
8065 }
8068 }
8070 /* Return the smallest alignment not less than SIZE. */
8072 static unsigned int
8074 {
8076 }
8077 \f
8078 /* Verify that OBJECT, a type or decl, is something we can implement
8079 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
8080 if we require atomic components. */
8082 static void
8084 {
8086 Node_Id gnat_node;
8089 tree size;
8091 /* There are three case of what OBJECT can be. It can be a type, in which
8092 case we take the size, alignment and mode from the type. It can be a
8093 declaration that was indirect, in which case the relevant values are
8094 that of the type being pointed to, or it can be a normal declaration,
8095 in which case the values are of the decl. The code below assumes that
8096 OBJECT is either a type or a decl. */
8098 {
8099 /* If this is an anonymous base type, nothing to check. Error will be
8100 reported on the source type. */
8107 }
8109 {
8113 }
8114 else
8115 {
8119 }
8121 /* Consider all floating-point types atomic and any types that that are
8122 represented by integers no wider than a machine word. */
8129 /* For the moment, also allow anything that has an alignment equal
8130 to its size and which is smaller than a word. */
8138 {
8147 }
8152 else
8155 }
8156 \f
8158 /* Helper for the intrin compatibility checks family. Evaluate whether
8159 two types are definitely incompatible. */
8161 static bool
8163 {
8178 {
8185 /* Assume designated types are ok. We'd need to account for char * and
8186 void * variants to do better, which could rapidly get messy and isn't
8187 clearly worth the effort. */
8192 }
8195 }
8197 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8198 on the Ada/builtin argument lists for the INB binding. */
8200 static bool
8202 {
8206 /* Sequence position of the last argument we checked. */
8210 {
8213 /* If one list is shorter than the other, they fail to match. */
8220 /* If we're done with the Ada args and not with the internal builtin
8221 args, or the other way around, complain. */
8224 {
8227 }
8231 {
8235 }
8237 /* Otherwise, check that types match for the current argument. */
8238 argpos ++;
8240 {
8244 }
8248 }
8251 }
8253 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8254 on the Ada/builtin return values for the INB binding. */
8256 static bool
8258 {
8262 /* Accept function imported as procedure, common and convenient. */
8267 /* Check return types compatibility otherwise. Note that this
8268 handles void/void as well. */
8270 {
8274 }
8277 }
8279 /* Check and return whether the Ada and gcc builtin profiles bound by INB are
8280 compatible. Issue relevant warnings when they are not.
8282 This is intended as a light check to diagnose the most obvious cases, not
8283 as a full fledged type compatiblity predicate. It is the programmer's
8284 responsibility to ensure correctness of the Ada declarations in Imports,
8285 especially when binding straight to a compiler internal. */
8287 static bool
8289 {
8290 /* Check compatibility on return values and argument lists, each responsible
8291 for posting warnings as appropriate. Ensure use of the proper sloc for
8292 this purpose. */
8305 }
8306 \f
8307 /* Return a FIELD_DECL node modeled on OLD_FIELD. FIELD_TYPE is its type
8308 and RECORD_TYPE is the type of the parent. If SIZE is nonzero, it is the
8309 specified size for this field. POS_LIST is a position list describing
8310 the layout of OLD_FIELD and SUBST_LIST a substitution list to be applied
8311 to this layout. */
8313 static tree
8317 {
8329 /* If the position is now a constant, we can set it as the position of the
8330 field when we make it. Otherwise, we need to deal with it specially. */
8333 else
8336 new_field
8342 {
8352 }
8360 }
8362 /* Return the REP part of RECORD_TYPE, if any. Otherwise return NULL. */
8364 static tree
8366 {
8369 /* The REP part is the first field, internal, another record, and its name
8370 doesn't start with an underscore (i.e. is not generated by the FE). */
8377 }
8379 /* Return the variant part of RECORD_TYPE, if any. Otherwise return NULL. */
8381 static tree
8383 {
8384 tree field;
8386 /* The variant part is the only internal field that is a qualified union. */
8393 }
8395 /* Return a new variant part modeled on OLD_VARIANT_PART. VARIANT_LIST is
8396 the list of variants to be used and RECORD_TYPE is the type of the parent.
8397 POS_LIST is a position list describing the layout of fields present in
8398 OLD_VARIANT_PART and SUBST_LIST a substitution list to be applied to this
8399 layout. */
8401 static tree
8406 {
8414 /* First create the type of the variant part from that of the old one. */
8418 /* If the position of the variant part is constant, subtract it from the
8419 size of the type of the parent to get the new size. This manual CSE
8420 reduces the code size when not optimizing. */
8422 {
8432 first_bit));
8435 }
8436 else
8439 /* Now finish up the new variants and populate the union type. */
8441 {
8445 /* Skip variants that don't belong to this nesting level. */
8449 /* Retrieve the list of fields already added to the new variant. */
8453 /* If the old variant had a variant subpart, we need to create a new
8454 variant subpart and add it to the field list. */
8458 {
8459 tree new_variant_subpart
8464 }
8466 /* Finish up the new variant and create the field. No need for debug
8467 info thanks to the XVS type. */
8473 new_field
8481 }
8483 /* Finish up the union type and create the variant part. No need for debug
8484 info thanks to the XVS type. */
8490 new_variant_part
8496 /* With multiple discriminants it is possible for an inner variant to be
8497 statically selected while outer ones are not; in this case, the list
8498 of fields of the inner variant is not flattened and we end up with a
8499 qualified union with a single member. Drop the useless container. */
8501 {
8510 }
8513 }
8515 /* Copy the size (and alignment and alias set) from OLD_TYPE to NEW_TYPE,
8516 which are both RECORD_TYPE, after applying the substitutions described
8517 in SUBST_LIST. */
8519 static void
8522 {
8546 SET_TYPE_ADA_SIZE
8550 /* Finalize the size. */
8553 }
8554 \f
8555 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a
8556 type with all size expressions that contain F in a PLACEHOLDER_EXPR
8557 updated by replacing F with R.
8559 The function doesn't update the layout of the type, i.e. it assumes
8560 that the substitution is purely formal. That's why the replacement
8561 value R must itself contain a PLACEHOLDER_EXPR. */
8563 tree
8565 {
8566 tree nt;
8571 {
8577 /* First the domain types of arrays. */
8580 {
8592 SET_TYPE_INDEX_TYPE
8596 }
8598 /* Then the subtypes. */
8601 {
8613 }
8628 /* These should never show up here. */
8632 {
8649 }
8654 {
8656 tree field;
8658 /* Start out with no fields, make new fields, and chain them
8659 in. If we haven't actually changed the type of any field,
8660 discard everything we've done and return the old type. */
8665 {
8670 {
8673 }
8677 {
8680 }
8682 /* Do the substitution inside the qualifier, if any. */
8684 {
8687 {
8690 }
8691 }
8698 }
8708 }
8712 }
8713 }
8714 \f
8715 /* Return the RM size of GNU_TYPE. This is the actual number of bits
8716 needed to represent the object. */
8718 tree
8720 {
8721 /* For integral types, we store the RM size explicitly. */
8725 /* Return the RM size of the actual data plus the size of the template. */
8728 return
8733 /* For record types, we store the size explicitly. */
8741 /* For other types, this is just the size. */
8743 }
8744 \f
8745 /* Return the name to be used for GNAT_ENTITY. If a type, create a
8746 fully-qualified name, possibly with type information encoding.
8747 Otherwise, return the name. */
8749 tree
8751 {
8754 }
8756 /* Return an identifier representing the external name to be used for
8757 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
8758 and the specified suffix. */
8760 tree
8762 {
8766 {
8770 }
8771 else
8774 /* A variable using the Stdcall convention lives in a DLL. We adjust
8775 its name to use the jump table, the _imp__NAME contains the address
8776 for the NAME variable. */
8779 {
8785 }
8788 }
8790 /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
8791 string, return a new IDENTIFIER_NODE that is the concatenation of
8792 the name followed by "___" and the specified suffix. */
8794 tree
8796 {
8803 }