| blob | 43ed0b33c3bde96e14c8e985187b2f05e079ff12 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2014, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License along with GCC; see the file COPYING3. If not see *
19 * <http://www.gnu.org/licenses/>. *
20 * *
21 * GNAT was originally developed by the GNAT team at New York University. *
22 * Extensive contributions were provided by Ada Core Technologies Inc. *
23 * *
24 ****************************************************************************/
56 /* "stdcall" and "thiscall" conventions should be processed in a specific way
57 on 32-bit x86/Windows only. The macros below are helpers to avoid having
58 to check for a Windows specific attribute throughout this unit. */
60 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
61 #ifdef TARGET_64BIT
62 #define Has_Stdcall_Convention(E) \
63 (!TARGET_64BIT && Convention (E) == Convention_Stdcall)
64 #define Has_Thiscall_Convention(E) \
65 (!TARGET_64BIT && is_cplusplus_method (E))
66 #else
67 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
68 #define Has_Thiscall_Convention(E) (is_cplusplus_method (E))
69 #endif
70 #else
71 #define Has_Stdcall_Convention(E) 0
72 #define Has_Thiscall_Convention(E) 0
73 #endif
77 /* Stack realignment is necessary for functions with foreign conventions when
78 the ABI doesn't mandate as much as what the compiler assumes - that is, up
79 to PREFERRED_STACK_BOUNDARY.
81 Such realignment can be requested with a dedicated function type attribute
82 on the targets that support it. We define FOREIGN_FORCE_REALIGN_STACK to
83 characterize the situations where the attribute should be set. We rely on
84 compiler configuration settings for 'main' to decide. */
86 #ifdef MAIN_STACK_BOUNDARY
87 #define FOREIGN_FORCE_REALIGN_STACK \
88 (MAIN_STACK_BOUNDARY < PREFERRED_STACK_BOUNDARY)
89 #else
90 #define FOREIGN_FORCE_REALIGN_STACK 0
91 #endif
93 struct incomplete
94 {
96 tree old_type;
97 Entity_Id full_type;
98 };
100 /* These variables are used to defer recursively expanding incomplete types
101 while we are processing an array, a record or a subprogram type. */
105 /* This variable is used to delay expanding From_Limited_With types until the
106 end of the spec. */
110 tree discriminant;
111 tree replacement;
116 /* The type of the variant. */
117 tree type;
119 /* The associated field. */
120 tree field;
122 /* The value of the qualifier. */
123 tree qual;
125 /* The type of the variant after transformation. */
126 tree new_type;
130 /* A hash table used to cache the result of annotate_value. */
175 /* The relevant constituents of a subprogram binding to a GCC builtin. Used
176 to pass around calls performing profile compatibility checks. */
185 \f
186 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
187 entity, return the equivalent GCC tree for that entity (a ..._DECL node)
188 and associate the ..._DECL node with the input GNAT defining identifier.
190 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
191 initial value (in GCC tree form). This is optional for a variable. For
192 a renamed entity, GNU_EXPR gives the object being renamed.
194 DEFINITION is nonzero if this call is intended for a definition. This is
195 used for separate compilation where it is necessary to know whether an
196 external declaration or a definition must be created if the GCC equivalent
197 was not created previously. The value of 1 is normally used for a nonzero
198 DEFINITION, but a value of 2 is used in special circumstances, defined in
199 the code. */
201 tree
203 {
204 /* Contains the kind of the input GNAT node. */
206 /* True if this is a type. */
208 /* True if debug info is requested for this entity. */
210 /* True if this entity is to be considered as imported. */
211 const bool imported_p
213 /* For a type, contains the equivalent GNAT node to be used in gigi. */
215 /* Temporary used to walk the GNAT tree. */
216 Entity_Id gnat_temp;
217 /* Contains the GCC DECL node which is equivalent to the input GNAT node.
218 This node will be associated with the GNAT node by calling at the end
219 of the `switch' statement. */
221 /* Contains the GCC type to be used for the GCC node. */
223 /* Contains the GCC size tree to be used for the GCC node. */
225 /* Contains the GCC name to be used for the GCC node. */
226 tree gnu_entity_name;
227 /* True if we have already saved gnu_decl as a GNAT association. */
229 /* True if we incremented defer_incomplete_level. */
231 /* True if we incremented force_global. */
233 /* True if we should check to see if elaborated during processing. */
235 /* True if we made GNU_DECL and its type here. */
237 /* Size and alignment of the GCC node, if meaningful. */
239 /* Contains the list of attributes directly attached to the entity. */
242 /* Since a use of an Itype is a definition, process it as such if it
243 is not in a with'ed unit. */
245 && is_type
249 {
250 /* Ensure that we are in a subprogram mentioned in the Scope chain of
251 this entity, our current scope is global, or we encountered a task
252 or entry (where we can't currently accurately check scoping). */
255 {
258 }
263 {
268 gnat_temp
280 && (current_function_decl
282 {
285 }
286 }
288 /* This abort means the Itype has an incorrect scope, i.e. that its
289 scope does not correspond to the subprogram it is declared in. */
291 }
293 /* If we've already processed this entity, return what we got last time.
294 If we are defining the node, we should not have already processed it.
295 In that case, we will abort below when we try to save a new GCC tree
296 for this object. We also need to handle the case of getting a dummy
297 type when a Full_View exists but be careful so as not to trigger its
298 premature elaboration. */
301 {
310 {
311 gnu_decl
315 }
318 }
320 /* If this is a numeric or enumeral type, or an access type, a nonzero Esize
321 must be specified unless it was specified by the programmer. Exceptions
322 are for access-to-protected-subprogram types and all access subtypes, as
323 another GNAT type is used to lay out the GCC type for them. */
334 /* The RM size must be specified for all discrete and fixed-point types. */
338 /* If we get here, it means we have not yet done anything with this entity.
339 If we are not defining it, it must be a type or an entity that is defined
340 elsewhere or externally, otherwise we should have defined it already. */
342 || type_annotate_only
343 || is_type
350 /* Get the name of the entity and set up the line number and filename of
351 the original definition for use in any decl we make. */
355 /* For cases when we are not defining (i.e., we are referencing from
356 another compilation unit) public entities, show we are at global level
357 for the purpose of computing scopes. Don't do this for components or
358 discriminants since the relevant test is whether or not the record is
359 being defined. */
367 /* Handle any attributes directly attached to the entity. */
371 /* Do some common processing for types. */
373 {
374 /* Compute the equivalent type to be used in gigi. */
377 /* Machine_Attributes on types are expected to be propagated to
378 subtypes. The corresponding Gigi_Rep_Items are only attached
379 to the first subtype though, so we handle the propagation here. */
386 /* Compute a default value for the size of an elementary type. */
388 {
398 else
403 }
404 }
407 {
409 /* If this is a use of a deferred constant without address clause,
410 get its full definition. */
414 {
415 gnu_decl
419 }
421 /* If we have an external constant that we are not defining, get the
422 expression that is was defined to represent. We may throw it away
423 later if it is not a constant. But do not retrieve the expression
424 if it is an allocator because the designated type might be dummy
425 at this point. */
431 {
435 /* The expression may contain N_Expression_With_Actions nodes and
436 thus object declarations from other units. In this case, even
437 though the expression will eventually be discarded since not a
438 constant, the declarations would be stuck either in the global
439 varpool or in the current scope. Therefore we force the local
440 context and create a fake scope that we'll zap at the end. */
442 {
445 }
455 }
457 /* Ignore deferred constant definitions without address clause since
458 they are processed fully in the front-end. If No_Initialization
459 is set, this is not a deferred constant but a constant whose value
460 is built manually. And constants that are renamings are handled
461 like variables. */
463 && !gnu_expr
467 {
471 }
473 /* Ignore constant definitions already marked with the error node. See
474 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
476 && gnu_expr
479 {
482 }
487 /* We used to special case VMS exceptions here to directly map them to
488 their associated condition code. Since this code had to be masked
489 dynamically to strip off the severity bits, this caused trouble in
490 the GCC/ZCX case because the "type" pointers we store in the tables
491 have to be static. We now don't special case here anymore, and let
492 the regular processing take place, which leaves us with a regular
493 exception data object for VMS exceptions too. The condition code
494 mapping is taken care of by the front end and the bitmasking by the
495 run-time library. */
500 {
501 /* The GNAT record where the component was defined. */
504 /* If the entity is an inherited component (in the case of extended
505 tagged record types), just return the original entity, which must
506 be a FIELD_DECL. Likewise for discriminants. If the entity is a
507 non-girder discriminant (in the case of derived untagged record
508 types), return the stored discriminant it renames. */
511 {
512 gnu_decl
517 }
519 /* If this is a discriminant of an extended tagged type used to rename
520 a discriminant of the parent type, return the latter. */
522 {
523 /* If the derived type is untagged, then this is a non-girder
524 discriminant and its Original_Record_Component must point to
525 the stored discriminant it renames (i.e. we should have taken
526 the previous branch). */
529 gnu_decl
534 }
536 /* Otherwise, if we are not defining this and we have no GCC type
537 for the containing record, make one for it. Then we should
538 have made our own equivalent. */
540 {
541 /* ??? If this is in a record whose scope is a protected
542 type and we have an Original_Record_Component, use it.
543 This is a workaround for major problems in protected type
544 handling. */
551 {
552 gnu_decl
558 }
564 }
566 else
567 /* Here we have no GCC type and this is a reference rather than a
568 definition. This should never happen. Most likely the cause is
569 reference before declaration in the GNAT tree for gnat_entity. */
571 }
577 /* Simple variables, loop variables, Out parameters and exceptions. */
578 object:
579 {
580 /* Always create a variable for volatile objects and variables seen
581 constant but with a Linker_Section pragma. */
582 bool const_flag
599 tree gnu_object_size;
602 {
606 else
608 }
610 /* Get the type after elaborating the renamed object. */
613 /* If this is a standard exception definition, then use the standard
614 exception type. This is necessary to make sure that imported and
615 exported views of exceptions are properly merged in LTO mode. */
620 /* For a debug renaming declaration, build a debug-only entity. */
622 {
623 /* Force a non-null value to make sure the symbol is retained. */
627 integer_minus_one_node));
634 }
636 /* If this is a loop variable, its type should be the base type.
637 This is because the code for processing a loop determines whether
638 a normal loop end test can be done by comparing the bounds of the
639 loop against those of the base type, which is presumed to be the
640 size used for computation. But this is not correct when the size
641 of the subtype is smaller than the type. */
645 /* Reject non-renamed objects whose type is an unconstrained array or
646 any object whose type is a dummy type or void. */
651 {
654 force_global--;
656 }
658 /* If an alignment is specified, use it if valid. Note that exceptions
659 are objects but don't have an alignment. We must do this before we
660 validate the size, since the alignment can affect the size. */
662 {
668 /* No point in changing the type if there is an address clause
669 as the final type of the object will be a reference type. */
672 else
673 {
676 gnu_type
680 /* If a padding record was made, declare it now since it will
681 never be declared otherwise. This is necessary to ensure
682 that its subtrees are properly marked. */
686 }
687 }
689 /* If we are defining the object, see if it has a Size and validate it
690 if so. If we are not defining the object and a Size clause applies,
691 simply retrieve the value. We don't want to ignore the clause and
692 it is expected to have been validated already. Then get the new
693 type, if any. */
702 {
703 gnu_type
709 }
711 /* If this object has self-referential size, it must be a record with
712 a default discriminant. We are supposed to allocate an object of
713 the maximum size in this case, unless it is a constant with an
714 initializing expression, in which case we can get the size from
715 that. Note that the resulting size may still be a variable, so
716 this may end up with an indirect allocation. */
719 {
721 {
724 {
725 /* If the initializing expression is itself a constant,
726 despite having a nominal type with self-referential
727 size, we can get the size directly from it. */
729 && TYPE_IS_PADDING_P
733 || DECL_READONLY_ONCE_ELAB
736 else
737 gnu_size
739 }
740 else
742 }
743 /* We may have no GNU_EXPR because No_Initialization is
744 set even though there's an Expression. */
749 gnu_size
751 (Etype
753 else
754 {
757 }
759 /* If we are at global level and the size isn't constant, call
760 elaborate_expression_1 to make a variable for it rather than
761 calculating it each time. */
766 }
768 /* If the size is zero byte, make it one byte since some linkers have
769 troubles with zero-sized objects. If the object will have a
770 template, that will make it nonzero so don't bother. Also avoid
771 doing that for an object renaming or an object with an address
772 clause, as we would lose useful information on the view size
773 (e.g. for null array slices) and we are not allocating the object
774 here anyway. */
786 /* If this is an object with no specified size and alignment, and
787 if either it is atomic or we are not optimizing alignment for
788 space and it is composite and not an exception, an Out parameter
789 or a reference to another object, and the size of its type is a
790 constant, set the alignment to the smallest one which is not
791 smaller than the size, with an appropriate cap. */
800 && !imported_p
804 {
807 /* No point in promoting the alignment if this doesn't prevent
808 BLKmode access to the object, in particular block copy, as
809 this will for example disable the NRV optimization for it.
810 No point in jumping through all the hoops needed in order
811 to support BIGGEST_ALIGNMENT if we don't really have to.
812 So we cap to the smallest alignment that corresponds to
813 a known efficient memory access pattern of the target. */
815 {
818 }
819 else
820 {
823 }
830 else
833 /* But make sure not to under-align the object. */
837 /* And honor the minimum valid atomic alignment, if any. */
838 #ifdef MINIMUM_ATOMIC_ALIGNMENT
841 #endif
842 }
844 /* If the object is set to have atomic components, find the component
845 type and validate it.
847 ??? Note that we ignore Has_Volatile_Components on objects; it's
848 not at all clear what to do in that case. */
850 {
859 }
861 /* Now check if the type of the object allows atomic access. Note
862 that we must test the type, even if this object has size and
863 alignment to allow such access, because we will be going inside
864 the padded record to assign to the object. We could fix this by
865 always copying via an intermediate value, but it's not clear it's
866 worth the effort. */
870 /* If this is an aliased object with an unconstrained nominal subtype,
871 make a type that includes the template. */
877 {
878 tree gnu_array
880 gnu_type
882 gnu_type,
885 debug_info_p);
886 }
888 /* ??? If this is an object of CW type initialized to a value, try to
889 ensure that the object is sufficient aligned for this value, but
890 without pessimizing the allocation. This is a kludge necessary
891 because we don't support dynamic alignment. */
898 #ifdef MINIMUM_ATOMIC_ALIGNMENT
899 /* If the size is a constant and no alignment is specified, force
900 the alignment to be the minimum valid atomic alignment. The
901 restriction on constant size avoids problems with variable-size
902 temporaries; if the size is variable, there's no issue with
903 atomic access. Also don't do this for a constant, since it isn't
904 necessary and can interfere with constant replacement. Finally,
905 do not do it for Out parameters since that creates an
906 size inconsistency with In parameters. */
916 #endif
918 /* Make a new type with the desired size and alignment, if needed.
919 But do not take into account alignment promotions to compute the
920 size of the object. */
923 {
929 /* If a padding record was made, declare it now since it will
930 never be declared otherwise. This is necessary to ensure
931 that its subtrees are properly marked. */
935 }
937 /* If this is a renaming, avoid as much as possible to create a new
938 object. However, in several cases, creating it is required.
939 This processing needs to be applied to the raw expression so
940 as to make it more likely to rename the underlying object. */
942 {
945 /* If the renamed object had padding, strip off the reference
946 to the inner object and reset our type. */
949 /* Strip useless conversions around the object. */
951 {
954 }
956 /* Or else, if the renamed object has an unconstrained type with
957 default discriminant, use the padded type. */
960 == gnu_type
964 /* Case 1: If this is a constant renaming stemming from a function
965 call, treat it as a normal object whose initial value is what is
966 being renamed. RM 3.3 says that the result of evaluating a
967 function call is a constant object. Treat constant literals
968 the same way. As a consequence, it can be the inner object of
969 a constant renaming. In this case, the renaming must be fully
970 instantiated, i.e. it cannot be a mere reference to (part of) an
971 existing object. */
973 {
980 }
982 /* Otherwise, see if we can proceed with a stabilized version of
983 the renamed entity or if we need to make a new object. */
985 {
989 /* Case 2: If the renaming entity need not be materialized and
990 the renamed expression is something we can stabilize, use
991 that for the renaming. At the global level, we can only do
992 this if we know no SAVE_EXPRs need be made, because the
993 expression we return might be used in arbitrary conditional
994 branches so we must force the evaluation of the SAVE_EXPRs
995 immediately and this requires a proper function context.
996 Note that an external constant is at the global level. */
1002 {
1003 maybe_stable_expr
1007 {
1008 /* ??? No DECL_EXPR is created so we need to mark
1009 the expression manually lest it is shared. */
1018 /* This assertion will fail if the renamed object
1019 isn't aligned enough as to make it possible to
1020 honor the alignment set on the renaming. */
1022 {
1023 unsigned int renamed_align
1028 }
1030 }
1032 /* The stabilization failed. Keep maybe_stable_expr
1033 untouched here to let the pointer case below know
1034 about that failure. */
1035 }
1037 /* Case 3: Make this into a constant pointer to the object we
1038 are to rename and attach the object to the pointer if it is
1039 something we can stabilize.
1041 From the proper scope, attached objects will be referenced
1042 directly instead of indirectly via the pointer to avoid
1043 subtle aliasing problems with non-addressable entities.
1044 They have to be stable because we must not evaluate the
1045 variables in the expression every time the renaming is used.
1046 The pointer is called a "renaming" pointer in this case.
1048 In the rare cases where we cannot stabilize the renamed
1049 object, we just make a "bare" pointer and the renamed
1050 object will always be accessed indirectly through it.
1052 Note that we need to preserve the volatility of the renamed
1053 object through the indirection. */
1062 /* If the previous attempt at stabilizing failed, there is
1063 no point in trying again and we reuse the result without
1064 attaching it to the pointer. In this case it will only
1065 be used as the initializing expression of the pointer and
1066 thus needs no special treatment with regard to multiple
1067 evaluations.
1069 Otherwise, try to stabilize and attach the expression to
1070 the pointer if the stabilization succeeds.
1072 Note that this might introduce SAVE_EXPRs and we don't
1073 check whether we are at the global level or not. This
1074 is fine since we are building a pointer initializer and
1075 neither the pointer nor the initializing expression can
1076 be accessed before the pointer elaboration has taken
1077 place in a correct program.
1079 These SAVE_EXPRs will be evaluated at the right place
1080 by either the evaluation of the initializer for the
1081 non-global case or the elaboration code for the global
1082 case, and will be attached to the elaboration procedure
1083 in the latter case. */
1085 {
1086 maybe_stable_expr
1091 }
1096 else
1097 gnu_expr
1102 }
1103 }
1105 /* Make a volatile version of this object's type if we are to make
1106 the object volatile. We also interpret 13.3(19) conservatively
1107 and disallow any optimizations for such a non-constant object. */
1109 || (!const_flag
1112 || imported_p
1119 /* If we are defining an aliased object whose nominal subtype is
1120 unconstrained, the object is a record that contains both the
1121 template and the object. If there is an initializer, it will
1122 have already been converted to the right type, but we need to
1123 create the template if there is no initializer. */
1125 && !gnu_expr
1128 /* Beware that padding might have been introduced above. */
1131 == RECORD_TYPE
1132 && TYPE_CONTAINS_TEMPLATE_P
1134 {
1135 tree template_field
1143 NULL_TREE);
1146 }
1148 /* Convert the expression to the type of the object except in the
1149 case where the object's type is unconstrained or the object's type
1150 is a padded record whose field is of self-referential size. In
1151 the former case, converting will generate unnecessary evaluations
1152 of the CONSTRUCTOR to compute the size and in the latter case, we
1153 want to only copy the actual data. Also don't convert to a record
1154 type with a variant part from a record type without one, to keep
1155 the object simpler. */
1160 && CONTAINS_PLACEHOLDER_P
1168 /* If this is a pointer that doesn't have an initializing expression,
1169 initialize it to NULL, unless the object is imported. */
1172 && !gnu_expr
1176 /* If we are defining the object and it has an Address clause, we must
1177 either get the address expression from the saved GCC tree for the
1178 object if it has a Freeze node, or elaborate the address expression
1179 here since the front-end has guaranteed that the elaboration has no
1180 effects in this case. */
1182 {
1184 tree gnu_address
1190 /* Ignore the size. It's either meaningless or was handled
1191 above. */
1193 /* Convert the type of the object to a reference type that can
1194 alias everything as per 13.3(19). */
1195 gnu_type
1199 const_flag
1203 /* If this is a deferred constant, the initializer is attached to
1204 the full view. */
1206 gnu_expr
1207 = gnat_to_gnu
1210 /* If we don't have an initializing expression for the underlying
1211 variable, the initializing expression for the pointer is the
1212 specified address. Otherwise, we have to make a COMPOUND_EXPR
1213 to assign both the address and the initial value. */
1216 else
1217 gnu_expr
1219 build_binary_op
1222 gnu_address),
1223 gnu_expr),
1224 gnu_address);
1225 }
1227 /* If it has an address clause and we are not defining it, mark it
1228 as an indirect object. Likewise for Stdcall objects that are
1229 imported. */
1233 {
1234 /* Convert the type of the object to a reference type that can
1235 alias everything as per 13.3(19). */
1236 gnu_type
1240 /* No point in taking the address of an initializing expression
1241 that isn't going to be used. */
1244 /* If it has an address clause whose value is known at compile
1245 time, make the object a CONST_DECL. This will avoid a
1246 useless dereference. */
1248 {
1249 Node_Id gnat_address
1253 {
1256 }
1257 }
1260 }
1262 /* If we are at top level and this object is of variable size,
1263 make the actual type a hidden pointer to the real type and
1264 make the initializer be a memory allocation and initialization.
1265 Likewise for objects we aren't defining (presumed to be
1266 external references from other packages), but there we do
1267 not set up an initialization.
1269 If the object's size overflows, make an allocator too, so that
1270 Storage_Error gets raised. Note that we will never free
1271 such memory, so we presume it never will get allocated. */
1274 || !definition
1276 || (gnu_size
1278 size_binop
1280 bitsize_unit_node)),
1282 || !definition
1284 {
1289 /* In case this was a aliased object whose nominal subtype is
1290 unconstrained, the pointer above will be a thin pointer and
1291 build_allocator will automatically make the template.
1293 If we have a template initializer only (that we made above),
1294 pretend there is none and rely on what build_allocator creates
1295 again anyway. Otherwise (if we have a full initializer), get
1296 the data part and feed that to build_allocator.
1298 If we are elaborating a mutable object, tell build_allocator to
1299 ignore a possibly simpler size from the initializer, if any, as
1300 we must allocate the maximum possible size in this case. */
1302 {
1307 {
1308 gnu_alloc_type
1314 else
1315 gnu_expr
1316 = build_component_ref
1320 }
1325 gnat_entity);
1327 gnu_expr
1331 }
1332 else
1333 {
1336 }
1337 }
1339 /* If this object would go into the stack and has an alignment larger
1340 than the largest stack alignment the back-end can honor, resort to
1341 a variable of "aligning type". */
1344 {
1345 /* Create the new variable. No need for extra room before the
1346 aligned field as this is in automatic storage. */
1347 tree gnu_new_type
1351 tree gnu_new_var
1356 /* Initialize the aligned field if we have an initializer. */
1358 add_stmt_with_node
1360 build_component_ref
1363 gnu_expr),
1364 gnat_entity);
1366 /* And setup this entity as a reference to the aligned field. */
1368 gnu_expr
1369 = build_unary_op
1377 }
1379 /* If this is an aliased object with an unconstrained nominal subtype,
1380 we make its type a thin reference, i.e. the reference counterpart
1381 of a thin pointer, so that it points to the array part. This is
1382 aimed at making it easier for the debugger to decode the object.
1383 Note that we have to do that this late because of the couple of
1384 allocation adjustments that might be made just above. */
1390 {
1391 tree gnu_array
1394 /* In case the object with the template has already been allocated
1395 just above, we have nothing to do here. */
1397 {
1398 tree gnu_unc_var
1404 gnu_expr
1411 }
1413 gnu_type
1415 }
1421 /* Convert the expression to the type of the object except in the
1422 case where the object's type is unconstrained or the object's type
1423 is a padded record whose field is of self-referential size. In
1424 the former case, converting will generate unnecessary evaluations
1425 of the CONSTRUCTOR to compute the size and in the latter case, we
1426 want to only copy the actual data. Also don't convert to a record
1427 type with a variant part from a record type without one, to keep
1428 the object simpler. */
1433 && CONTAINS_PLACEHOLDER_P
1441 /* If this name is external or there was a name specified, use it,
1442 unless this is a VMS exception object since this would conflict
1443 with the symbol we need to export in addition. Don't use the
1444 Interface_Name if there is an address clause (see CD30005). */
1453 /* If this is an aggregate constant initialized to a constant, force it
1454 to be statically allocated. This saves an initialization copy. */
1456 && const_flag
1465 /* Deal with a pragma Linker_Section on a constant or variable. */
1471 /* Now create the variable or the constant and set various flags. */
1472 gnu_decl
1481 /* If we are defining an Out parameter and optimization isn't enabled,
1482 create a fake PARM_DECL for debugging purposes and make it point to
1483 the VAR_DECL. Suppress debug info for the latter but make sure it
1484 will live in memory so that it can be accessed from within the
1485 debugger through the PARM_DECL. */
1487 && definition
1488 && debug_info_p
1489 && !optimize
1491 {
1498 }
1500 /* If this is a loop parameter, set the corresponding flag. */
1504 /* If this is a renaming pointer, attach the renamed object to it and
1505 register it if we are at the global level. Note that an external
1506 constant is at the global level. */
1508 {
1511 {
1514 }
1515 }
1517 /* If this is a constant and we are defining it or it generates a real
1518 symbol at the object level and we are referencing it, we may want
1519 or need to have a true variable to represent it:
1520 - if optimization isn't enabled, for debugging purposes,
1521 - if the constant is public and not overlaid on something else,
1522 - if its address is taken,
1523 - if either itself or its type is aliased. */
1532 {
1533 tree gnu_corr_var
1537 gnat_entity);
1541 /* As debugging information will be generated for the variable,
1542 do not generate debugging information for the constant. */
1545 else
1547 }
1549 /* If this is a constant, even if we don't need a true variable, we
1550 may need to avoid returning the initializer in every case. That
1551 can happen for the address of a (constant) constructor because,
1552 upon dereferencing it, the constructor will be reinjected in the
1553 tree, which may not be valid in every case; see lvalue_required_p
1554 for more details. */
1558 /* If this object is declared in a block that contains a block with an
1559 exception handler, and we aren't using the GCC exception mechanism,
1560 we must force this variable in memory in order to avoid an invalid
1561 optimization. */
1566 /* If this is a local variable with non-BLKmode and aggregate type,
1567 and optimization isn't enabled, then force it in memory so that
1568 a register won't be allocated to it with possible subparts left
1569 uninitialized and reaching the register allocator. */
1579 /* If we are defining an object with variable size or an object with
1580 fixed size that will be dynamically allocated, and we are using the
1581 setjmp/longjmp exception mechanism, update the setjmp buffer. */
1594 gnat_entity);
1596 /* Back-annotate Esize and Alignment of the object if not already
1597 known. Note that we pick the values of the type, not those of
1598 the object, to shield ourselves from low-level platform-dependent
1599 adjustments like alignment promotion. This is both consistent with
1600 all the treatment above, where alignment and size are set on the
1601 type of the object and not on the object directly, and makes it
1602 possible to support all confirming representation clauses. */
1604 used_by_ref);
1605 }
1609 /* Return a TYPE_DECL for "void" that we previously made. */
1614 /* A special case: for the types Character and Wide_Character in
1615 Standard, we do not list all the literals. So if the literals
1616 are not specified, make this an unsigned integer type. */
1618 {
1622 /* Set TYPE_STRING_FLAG for Character and Wide_Character types.
1623 This is needed by the DWARF-2 back-end to distinguish between
1624 unsigned integer types and character types. */
1626 }
1627 else
1628 {
1629 /* We have a list of enumeral constants in First_Literal. We make a
1630 CONST_DECL for each one and build into GNU_LITERAL_LIST the list
1631 to be placed into TYPE_FIELDS. Each node is itself a TREE_LIST
1632 whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
1633 value of the literal. But when we have a regular boolean type, we
1634 simplify this a little by using a BOOLEAN_TYPE. */
1639 Entity_Id gnat_literal;
1652 {
1653 tree gnu_value
1655 tree gnu_literal
1659 /* Do not generate debug info for individual enumerators. */
1662 gnu_list
1664 }
1669 /* Note that the bounds are updated at the end of this function
1670 to avoid an infinite recursion since they refer to the type. */
1672 }
1678 /* For integer types, just make a signed type the appropriate number
1679 of bits. */
1684 {
1685 /* For modular types, make the unsigned type of the proper number
1686 of bits and then set up the modulus, if required. */
1689 /* Packed array types are supposed to be subtypes only. */
1694 /* Get the modulus in this type. If it overflows, assume it is because
1695 it is equal to 2**Esize. Note that there is no overflow checking
1696 done on unsigned type, so we detect the overflow by looking for
1697 a modulus of zero, which is otherwise invalid. */
1701 {
1706 }
1708 /* If the upper bound is not maximal, make an extra subtype. */
1711 {
1718 }
1719 }
1728 /* For integral subtypes, we make a new INTEGER_TYPE. Note that we do
1729 not want to call create_range_type since we would like each subtype
1730 node to be distinct. ??? Historically this was in preparation for
1731 when memory aliasing is implemented, but that's obsolete now given
1732 the call to relate_alias_sets below.
1734 The TREE_TYPE field of the INTEGER_TYPE points to the base type;
1735 this fact is used by the arithmetic conversion functions.
1737 We elaborate the Ancestor_Subtype if it is not in the current unit
1738 and one of our bounds is non-static. We do this to ensure consistent
1739 naming in the case where several subtypes share the same bounds, by
1740 elaborating the first such subtype first, thus using its name. */
1749 /* Set the precision to the Esize except for bit-packed arrays. */
1754 /* This should be an unsigned type if the base type is unsigned or
1755 if the lower bound is constant and non-negative or if the type
1756 is biased. */
1761 else
1765 SET_TYPE_RM_MIN_VALUE
1773 SET_TYPE_RM_MAX_VALUE
1784 /* Inherit our alias set from what we're a subtype of. Subtypes
1785 are not different types and a pointer can designate any instance
1786 within a subtype hierarchy. */
1789 /* One of the above calls might have caused us to be elaborated,
1790 so don't blow up if so. */
1792 {
1795 }
1797 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
1801 /* For a packed array, make the original array type a parallel type. */
1806 gnat_to_gnu_type
1809 discrete_type:
1811 /* We have to handle clauses that under-align the type specially. */
1814 && Present
1817 {
1821 }
1823 /* If the type we are dealing with represents a bit-packed array,
1824 we need to have the bits left justified on big-endian targets
1825 and right justified on little-endian targets. We also need to
1826 ensure that when the value is read (e.g. for comparison of two
1827 such values), we only get the good bits, since the unused bits
1828 are uninitialized. Both goals are accomplished by wrapping up
1829 the modular type in an enclosing record type. */
1832 {
1835 /* Set the RM size before wrapping up the original type. */
1840 /* Create a stripped-down declaration, mainly for debugging. */
1842 gnat_entity);
1844 /* Now save it and build the enclosing record type. */
1854 /* Propagate the alignment of the modular type to the record type,
1855 unless there is an alignment clause that under-aligns the type.
1856 This means that bit-packed arrays are given "ceil" alignment for
1857 their size by default, which may seem counter-intuitive but makes
1858 it possible to overlay them on modular types easily. */
1864 /* Don't declare the field as addressable since we won't be taking
1865 its address and this would prevent create_field_decl from making
1866 a bitfield. */
1867 gnu_field
1871 /* Do not emit debug info until after the parallel type is added. */
1877 {
1878 /* Make the original array type a parallel type. */
1881 gnat_to_gnu_type
1885 }
1886 }
1888 /* If the type we are dealing with has got a smaller alignment than the
1889 natural one, we need to wrap it up in a record type and misalign the
1890 latter; we reuse the padding machinery for this purpose. Note that,
1891 even if the record type is marked as packed because of misalignment,
1892 we don't pack the field so as to give it the size of the type. */
1894 {
1897 /* Set the RM size before wrapping up the type. */
1901 /* Create a stripped-down declaration, mainly for debugging. */
1903 gnat_entity);
1905 /* Now save it and build the enclosing record type. */
1917 /* Don't declare the field as addressable since we won't be taking
1918 its address and this would prevent create_field_decl from making
1919 a bitfield. */
1920 gnu_field
1928 }
1933 /* If this is a VAX floating-point type, use an integer of the proper
1934 size. All the operations will be handled with ASM statements. */
1936 {
1941 sizetype));
1943 }
1945 /* The type of the Low and High bounds can be our type if this is
1946 a type from Standard, so set them at the end of the function. */
1954 {
1957 }
1959 /* See the E_Signed_Integer_Subtype case for the rationale. */
1976 SET_TYPE_RM_MIN_VALUE
1984 SET_TYPE_RM_MAX_VALUE
1992 /* Inherit our alias set from what we're a subtype of, as for
1993 integer subtypes. */
1996 /* One of the above calls might have caused us to be elaborated,
1997 so don't blow up if so. */
2001 /* Array and String Types and Subtypes
2003 Unconstrained array types are represented by E_Array_Type and
2004 constrained array types are represented by E_Array_Subtype. There
2005 are no actual objects of an unconstrained array type; all we have
2006 are pointers to that type.
2008 The following fields are defined on array types and subtypes:
2010 Component_Type Component type of the array.
2011 Number_Dimensions Number of dimensions (an int).
2012 First_Index Type of first index. */
2016 {
2017 const bool convention_fortran_p
2020 tree gnu_template_type;
2021 tree gnu_ptr_template;
2028 tree comp_type;
2030 /* Create the type for the component now, as it simplifies breaking
2031 type reference loops. */
2032 comp_type
2035 {
2036 /* As a side effect, the type may have been translated. */
2039 }
2041 /* We complete an existing dummy fat pointer type in place. This both
2042 avoids further complex adjustments in update_pointer_to and yields
2043 better debugging information in DWARF by leveraging the support for
2044 incomplete declarations of "tagged" types in the DWARF back-end. */
2047 {
2050 /* Save the contents of the dummy type for update_pointer_to. */
2052 gnu_ptr_template =
2055 }
2056 else
2057 {
2061 }
2063 /* Make a node for the array. If we are not defining the array
2064 suppress expanding incomplete types. */
2068 {
2069 defer_incomplete_level++;
2071 }
2073 /* Build the fat pointer type. Use a "void *" object instead of
2074 a pointer to the array type since we don't have the array type
2075 yet (it will reference the fat pointer via the bounds). */
2076 tem
2084 {
2085 /* We are going to lay it out again so reset the alias set. */
2091 {
2094 }
2095 }
2096 else
2097 {
2100 }
2102 /* Build a reference to the template from a PLACEHOLDER_EXPR that
2103 is the fat pointer. This will be used to access the individual
2104 fields once we build them. */
2108 gnu_template_reference
2113 /* Now create the GCC type for each index and add the fields for that
2114 index to the template. */
2120 {
2122 tree gnu_index_base_type
2127 /* Make the FIELD_DECLs for the low and high bounds of this
2128 type and then make extractions of these fields from the
2129 template. */
2132 gnu_index_base_type,
2140 gnu_index_base_type,
2148 /* We can't use build_component_ref here since the template type
2149 isn't complete yet. */
2152 NULL_TREE);
2155 NULL_TREE);
2161 /* Compute the size of this dimension. See the E_Array_Subtype
2162 case below for the rationale. */
2163 gnu_high
2167 gnu_max,
2170 /* Make a range type with the new range in the Ada base type.
2171 Then make an index type with the size range in sizetype. */
2175 gnu_orig_min,
2176 gnu_orig_max),
2177 gnat_entity);
2179 /* Update the maximum size of the array in elements. */
2181 {
2183 tree gnu_min
2185 tree gnu_max
2187 tree gnu_this_max
2192 size_zero_node);
2197 else
2198 gnu_max_size
2200 }
2204 }
2206 /* Install all the fields into the template. */
2211 gnu_template_fields
2214 debug_info_p);
2217 /* If Component_Size is not already specified, annotate it with the
2218 size of the component. */
2223 /* Compute the maximum size of the array in units and bits. */
2225 {
2231 }
2232 else
2235 /* Now build the array type. */
2238 {
2246 /* If it is passed by reference, force BLKmode to ensure that
2247 objects of this type will always be put in memory. */
2251 }
2253 /* If an alignment is specified, use it if valid. But ignore it
2254 for the original type of packed array types. If the alignment
2255 was requested with an explicit alignment clause, state so. */
2258 {
2264 }
2268 /* Adjust the type of the pointer-to-array field of the fat pointer
2269 and record the aliasing relationships if necessary. */
2274 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2275 corresponding fat pointer. */
2282 /* If the maximum size doesn't overflow, use it. */
2288 {
2293 }
2297 gnat_entity);
2299 /* Give the fat pointer type a name. If this is a packed type, tell
2300 the debugger how to interpret the underlying bits. */
2303 else
2307 gnat_entity);
2309 /* Create the type to be designated by thin pointers: a record type for
2310 the array and its template. We used to shift the fields to have the
2311 template at a negative offset, but this was somewhat of a kludge; we
2312 now shift thin pointer values explicitly but only those which have a
2313 TYPE_UNCONSTRAINED_ARRAY attached to the designated RECORD_TYPE. */
2316 debug_info_p);
2320 }
2326 /* This is the actual data type for array variables. Multidimensional
2327 arrays are implemented as arrays of arrays. Note that arrays which
2328 have sparse enumeration subtypes as index components create sparse
2329 arrays, which is obviously space inefficient but so much easier to
2330 code for now.
2332 Also note that the subtype never refers to the unconstrained array
2333 type, which is somewhat at variance with Ada semantics.
2335 First check to see if this is simply a renaming of the array type.
2336 If so, the result is the array type. */
2340 ;
2341 else
2342 {
2344 const bool convention_fortran_p
2353 /* First create the GCC type for each index and find out whether
2354 special types are needed for debugging information. */
2357 gnat_base_index
2363 {
2369 tree gnu_base_index_type
2373 tree gnu_high;
2375 /* See if the base array type is already flat. If it is, we
2376 are probably compiling an ACATS test but it will cause the
2377 code below to malfunction if we don't handle it specially. */
2381 {
2385 }
2387 /* Similarly, if one of the values overflows in sizetype and the
2388 range is null, use 1..0 for the sizetype bounds. */
2393 {
2397 }
2399 /* If the minimum and maximum values both overflow in sizetype,
2400 but the difference in the original type does not overflow in
2401 sizetype, ignore the overflow indication. */
2405 && !TREE_OVERFLOW
2408 gnu_orig_max,
2409 gnu_orig_min))))
2410 {
2414 }
2416 /* Compute the size of this dimension in the general case. We
2417 need to provide GCC with an upper bound to use but have to
2418 deal with the "superflat" case. There are three ways to do
2419 this. If we can prove that the array can never be superflat,
2420 we can just use the high bound of the index type. */
2423 /* Packed Array Types are never superflat. */
2427 /* Otherwise, if the high bound is constant but the low bound is
2428 not, we use the expression (hb >= lb) ? lb : hb + 1 for the
2429 lower bound. Note that the comparison must be done in the
2430 original type to avoid any overflow during the conversion. */
2433 {
2435 gnu_min
2438 boolean_type_node,
2439 gnu_orig_max,
2440 gnu_orig_min),
2441 gnu_min,
2443 size_one_node));
2444 }
2446 /* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
2447 in all the other cases. Note that, here as well as above,
2448 the condition used in the comparison must be equivalent to
2449 the condition (length != 0). This is relied upon in order
2450 to optimize array comparisons in compare_arrays. Moreover
2451 we use int_const_binop for the shift by 1 if the bound is
2452 constant to avoid any unwanted overflow. */
2453 else
2454 gnu_high
2457 boolean_type_node,
2458 gnu_orig_max,
2459 gnu_orig_min),
2460 gnu_max,
2463 size_one_node)
2465 size_one_node));
2467 /* Reuse the index type for the range type. Then make an index
2468 type with the size range in sizetype. */
2471 gnat_entity);
2473 /* Update the maximum size of the array in elements. Here we
2474 see if any constraint on the index type of the base type
2475 can be used in the case of self-referential bound on the
2476 index type of the subtype. We look for a non-"infinite"
2477 and non-self-referential bound from any type involved and
2478 handle each bound separately. */
2480 {
2483 tree gnu_base_index_base_type
2485 tree gnu_base_base_min
2488 tree gnu_base_base_max
2509 else
2510 {
2511 tree gnu_this_max
2515 gnu_base_max,
2516 gnu_base_min)),
2517 size_zero_node);
2522 else
2523 gnu_max_size
2525 }
2526 }
2528 /* We need special types for debugging information to point to
2529 the index types if they have variable bounds, are not integer
2530 types, are biased or are wider than sizetype. */
2541 }
2543 /* Then flatten: create the array of arrays. For an array type
2544 used to implement a packed array, get the component type from
2545 the original array type since the representation clauses that
2546 can affect it are on the latter. */
2549 {
2554 /* One of the above calls might have caused us to be elaborated,
2555 so don't blow up if so. */
2557 {
2560 }
2561 }
2562 else
2563 {
2565 debug_info_p);
2567 /* One of the above calls might have caused us to be elaborated,
2568 so don't blow up if so. */
2570 {
2573 }
2574 }
2576 /* Compute the maximum size of the array in units and bits. */
2578 {
2584 }
2585 else
2588 /* Now build the array type. */
2590 {
2597 /* See the E_Array_Type case for the rationale. */
2601 }
2603 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
2607 /* If we are at file level and this is a multi-dimensional array,
2608 we need to make a variable corresponding to the stride of the
2609 inner dimensions. */
2611 {
2613 tree gnu_arr_type;
2619 {
2627 /* ??? For now, store the size as a multiple of the
2628 alignment of the element type in bytes so that we
2629 can see the alignment from the tree. */
2632 gnat_entity,
2637 /* ??? create_type_decl is not invoked on the inner types so
2638 the MULT_EXPR node built above will never be marked. */
2640 }
2641 }
2643 /* If we need to write out a record type giving the names of the
2644 bounds for debugging purposes, do it now and make the record
2645 type a parallel type. This is not needed for a packed array
2646 since the bounds are conveyed by the original array type. */
2648 && debug_info_p
2650 {
2653 tree gnu_field;
2659 {
2663 /* Make sure to reference the types themselves, and not just
2664 their names, as the debugger may fall back on them. */
2670 }
2674 }
2676 /* If this is a packed array type, make the original array type a
2677 parallel type. Otherwise, do it for the base array type if it
2678 isn't artificial to make sure it is kept in the debug info. */
2680 {
2684 gnat_to_gnu_type
2686 else
2687 {
2688 tree gnu_base_decl
2693 }
2694 }
2701 /* If the size is self-referential and the maximum size doesn't
2702 overflow, use it. */
2704 && gnu_max_size
2709 {
2715 }
2717 /* Set our alias set to that of our base type. This gives all
2718 array subtypes the same alias set. */
2721 /* If this is a packed type, make this type the same as the packed
2722 array type, but do some adjusting in the type first. */
2724 {
2725 Entity_Id gnat_index;
2726 tree gnu_inner;
2728 /* First finish the type we had been making so that we output
2729 debugging information for it. */
2732 gnu_type
2736 /* Make it artificial only if the base type was artificial too.
2737 That's sort of "morally" true and will make it possible for
2738 the debugger to look it up by name in DWARF, which is needed
2739 in order to decode the packed array type. */
2740 gnu_decl
2746 /* Save it as our equivalent in case the call below elaborates
2747 this type again. */
2762 /* We need to attach the index type to the type we just made so
2763 that the actual bounds can later be put into a template. */
2768 {
2770 {
2771 /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
2772 TYPE_MODULUS for modular types so we make an extra
2773 subtype if necessary. */
2775 {
2776 tree gnu_subtype
2785 }
2789 #ifdef ENABLE_CHECKING
2790 /* Check for other cases of overloading. */
2792 #endif
2793 }
2798 SET_TYPE_ACTUAL_BOUNDS
2805 SET_TYPE_ACTUAL_BOUNDS
2811 }
2812 }
2814 else
2815 /* Abort if packed array with no Packed_Array_Type field set. */
2817 }
2821 /* Create the type for a string literal. */
2822 {
2823 Entity_Id gnat_full_type
2828 tree gnu_string_array_type
2830 tree gnu_string_index_type
2833 tree gnu_lower_bound
2836 tree gnu_length
2838 gnu_string_index_type);
2839 tree gnu_upper_bound
2841 gnu_lower_bound,
2843 integer_one_node));
2844 tree gnu_index_type
2848 gnu_lower_bound,
2849 gnu_upper_bound),
2850 gnat_entity);
2852 gnu_type
2855 gnu_index_type);
2859 }
2862 /* Record Types and Subtypes
2864 The following fields are defined on record types:
2866 Has_Discriminants True if the record has discriminants
2867 First_Discriminant Points to head of list of discriminants
2868 First_Entity Points to head of list of fields
2869 Is_Tagged_Type True if the record is tagged
2871 Implementation of Ada records and discriminated records:
2873 A record type definition is transformed into the equivalent of a C
2874 struct definition. The fields that are the discriminants which are
2875 found in the Full_Type_Declaration node and the elements of the
2876 Component_List found in the Record_Type_Definition node. The
2877 Component_List can be a recursive structure since each Variant of
2878 the Variant_Part of the Component_List has a Component_List.
2880 Processing of a record type definition comprises starting the list of
2881 field declarations here from the discriminants and the calling the
2882 function components_to_record to add the rest of the fields from the
2883 component list and return the gnu type node. The function
2884 components_to_record will call itself recursively as it traverses
2885 the tree. */
2889 {
2890 gnu_type
2891 = build_complex_type
2892 (get_unpadded_type
2895 (Component_List
2896 (Type_Definition
2900 }
2902 {
2905 Node_Id gnat_constr;
2906 Entity_Id gnat_field;
2908 tree gnu_get_parent;
2909 /* Set PACKED in keeping with gnat_to_gnu_field. */
2910 const int packed
2922 const bool is_extension
2928 /* See if all fields have a rep clause. Stop when we find one
2929 that doesn't. */
2937 {
2940 }
2942 /* If this is a record extension, go a level further to find the
2943 record definition. Also, verify we have a Parent_Subtype. */
2945 {
2952 }
2954 /* Make a node for the record. If we are not defining the record,
2955 suppress expanding incomplete types. */
2964 {
2965 defer_incomplete_level++;
2967 }
2969 /* If both a size and rep clause was specified, put the size in
2970 the record type now so that it can get the proper mode. */
2975 /* Always set the alignment here so that it can be used to
2976 set the mode, if it is making the alignment stricter. If
2977 it is invalid, it will be checked again below. If this is to
2978 be Atomic, choose a default alignment of a word unless we know
2979 the size and it's smaller. */
2984 {
2988 }
2989 /* If a type needs strict alignment, the minimum size will be the
2990 type size instead of the RM size (see validate_size). Cap the
2991 alignment, lest it causes this type size to become too large. */
2993 {
2998 }
2999 else
3002 /* If we have a Parent_Subtype, make a field for the parent. If
3003 this record has rep clauses, force the position to zero. */
3005 {
3008 tree gnu_parent;
3010 /* A major complexity here is that the parent subtype will
3011 reference our discriminants in its Stored_Constraint list.
3012 But those must reference the parent component of this record
3013 which is precisely of the parent subtype we have not built yet!
3014 To break the circle we first build a dummy COMPONENT_REF which
3015 represents the "get to the parent" operation and initialize
3016 each of those discriminants to a COMPONENT_REF of the above
3017 dummy parent referencing the corresponding discriminant of the
3018 base type of the parent subtype. */
3023 gnu_dummy_parent_type),
3024 NULL_TREE);
3031 {
3032 tree gnu_field
3035 save_gnu_tree
3040 }
3042 /* Then we build the parent subtype. If it has discriminants but
3043 the type itself has unknown discriminants, this means that it
3044 doesn't contain information about how the discriminants are
3045 derived from those of the ancestor type, so it cannot be used
3046 directly. Instead it is built by cloning the parent subtype
3047 of the underlying record view of the type, for which the above
3048 derivation of discriminants has been made explicit. */
3051 {
3054 /* If we are defining the type, the underlying record
3055 view must already have been elaborated at this point.
3056 Otherwise do it now as its parent subtype cannot be
3057 technically elaborated on its own. */
3060 else
3065 /* Substitute the "get to the parent" of the type for that
3066 of its underlying record view in the cloned type. */
3071 {
3073 tree gnu_ref
3076 gnu_parent
3078 }
3079 }
3080 else
3083 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
3084 initially built. The discriminants must reference the fields
3085 of the parent subtype and not those of its base type for the
3086 placeholder machinery to properly work. */
3088 {
3089 /* The actual parent subtype is the full view. */
3091 {
3094 else
3096 }
3102 {
3112 }
3113 }
3115 /* The "get to the parent" COMPONENT_REF must be given its
3116 proper type... */
3119 /* ...and reference the _Parent field of this record. */
3120 gnu_field
3123 has_rep
3125 has_rep
3131 }
3133 /* Make the fields for the discriminants and put them into the record
3134 unless it's an Unchecked_Union. */
3139 {
3140 /* If this is a record extension and this discriminant is the
3141 renaming of another discriminant, we've handled it above. */
3146 gnu_field
3148 debug_info_p);
3150 /* Make an expression using a PLACEHOLDER_EXPR from the
3151 FIELD_DECL node just created and link that with the
3152 corresponding GNAT defining identifier. */
3160 {
3163 }
3164 }
3166 /* If we have a derived untagged type that renames discriminants in
3167 the root type, the (stored) discriminants are a just copy of the
3168 discriminants of the root type. This means that any constraints
3169 added by the renaming in the derivation are disregarded as far
3170 as the layout of the derived type is concerned. To rescue them,
3171 we change the type of the (stored) discriminants to a subtype
3172 with the bounds of the type of the visible discriminants. */
3174 && !is_extension
3180 /* Ignore access discriminants. */
3183 {
3186 tree gnu_ref
3190 /* GNU_REF must be an expression using a PLACEHOLDER_EXPR built
3191 just above for one of the stored discriminants. */
3195 {
3197 tree gnu_subtype
3208 }
3209 }
3211 /* Add the fields into the record type and finish it up. */
3219 /* If it is passed by reference, force BLKmode to ensure that objects
3220 of this type will always be put in memory. */
3225 /* We used to remove the associations of the discriminants and _Parent
3226 for validity checking but we may need them if there's a Freeze_Node
3227 for a subtype used in this record. */
3230 /* Fill in locations of fields. */
3233 /* If there are any entities in the chain corresponding to components
3234 that we did not elaborate, ensure we elaborate their types if they
3235 are Itypes. */
3245 /* If this is a record type associated with an exception definition,
3246 equate its fields to those of the standard exception type. This
3247 will make it possible to convert between them. */
3249 {
3250 tree gnu_std_field;
3253 gnu_field;
3258 }
3259 }
3263 /* If an equivalent type is present, that is what we should use.
3264 Otherwise, fall through to handle this like a record subtype
3265 since it may have constraints. */
3267 {
3271 }
3273 /* ... fall through ... */
3276 /* If Cloned_Subtype is Present it means this record subtype has
3277 identical layout to that type or subtype and we should use
3278 that GCC type for this one. The front end guarantees that
3279 the component list is shared. */
3281 {
3286 }
3288 /* Otherwise, first ensure the base type is elaborated. Then, if we are
3289 changing the type, make a new type with each field having the type of
3290 the field in the new subtype but the position computed by transforming
3291 every discriminant reference according to the constraints. We don't
3292 see any difference between private and non-private type here since
3293 derivations from types should have been deferred until the completion
3294 of the private type. */
3295 else
3296 {
3298 tree gnu_base_type;
3301 {
3302 defer_incomplete_level++;
3304 }
3309 {
3312 }
3314 /* If this is a record subtype associated with a dispatch table,
3315 strip the suffix. This is necessary to make sure 2 different
3316 subtypes associated with the imported and exported views of a
3317 dispatch table are properly merged in LTO mode. */
3319 {
3326 }
3328 /* When the subtype has discriminants and these discriminants affect
3329 the initial shape it has inherited, factor them in. But for an
3330 Unchecked_Union (it must be an Itype), just return the type.
3331 We can't just test Is_Constrained because private subtypes without
3332 discriminants of types with discriminants with default expressions
3333 are Is_Constrained but aren't constrained! */
3340 {
3346 Entity_Id gnat_field;
3354 /* Set the size, alignment and alias set of the new type to
3355 match that of the old one, doing required substitutions. */
3357 gnu_subst_list);
3361 else
3364 /* Look for REP and variant parts in the base type. */
3368 /* If there is a variant part, we must compute whether the
3369 constraints statically select a particular variant. If
3370 so, we simply drop the qualified union and flatten the
3371 list of fields. Otherwise we'll build a new qualified
3372 union for the variants that are still relevant. */
3374 {
3378 gnu_variant_list
3380 gnu_subst_list,
3381 vNULL);
3383 /* If all the qualifiers are unconditionally true, the
3384 innermost variant is statically selected. */
3388 {
3391 }
3393 /* Otherwise, create the new variants. */
3396 {
3399 tree suffix
3401 IDENTIFIER_POINTER
3407 gnu_subst_list);
3409 }
3410 }
3411 else
3412 {
3415 }
3417 /* Make a list of fields and their position in the base type. */
3418 gnu_pos_list
3425 /* Now go down every component in the subtype and compute its
3426 size and position from those of the component in the base
3427 type and from the constraints of the subtype. */
3435 && Underlying_Type
3438 {
3440 Entity_Id gnat_old_field
3442 tree gnu_old_field
3448 /* If the type is the same, retrieve the GCC type from the
3449 old field to take into account possible adjustments. */
3452 else
3455 /* If there was a component clause, the field types must be
3456 the same for the type and subtype, so copy the data from
3457 the old field to avoid recomputation here. Also if the
3458 field is justified modular and the optimization in
3459 gnat_to_gnu_field was applied. */
3465 {
3468 }
3470 /* If the old field was packed and of constant size, we
3471 have to get the old size here, as it might differ from
3472 what the Etype conveys and the latter might overlap
3473 onto the following field. Try to arrange the type for
3474 possible better packing along the way. */
3478 {
3483 gnu_field_type
3485 }
3487 else
3490 /* If the context of the old field is the base type or its
3491 REP part (if any), put the field directly in the new
3492 type; otherwise look up the context in the variant list
3493 and put the field either in the new type if there is a
3494 selected variant or in one of the new variants. */
3496 || (gnu_rep_part
3499 else
3500 {
3503 tree rep_part;
3511 {
3514 else
3516 }
3517 else
3518 /* The front-end may pass us "ghost" components if
3519 it fails to recognize that a constrained subtype
3520 is statically constrained. Discard them. */
3522 }
3524 /* Now create the new field modeled on the old one. */
3525 gnu_field
3531 /* Put it in one of the new variants directly. */
3533 {
3536 }
3538 /* To match the layout crafted in components_to_record,
3539 if this is the _Tag or _Parent field, put it before
3540 any other fields. */
3545 /* Similarly, if this is the _Controller field, put
3546 it before the other fields except for the _Tag or
3547 _Parent field. */
3549 {
3552 }
3554 /* Otherwise, if this is a regular field, put it after
3555 the other fields. */
3556 else
3557 {
3564 }
3567 }
3569 /* If there is a variant list, a selected variant and the fields
3570 all have a constant position, put them in order of increasing
3571 position to match that of constant CONSTRUCTORs. Likewise if
3572 there is no variant list but a REP part, since the latter has
3573 been flattened in the process. */
3577 {
3589 {
3592 }
3593 }
3595 /* If there is a variant list and no selected variant, we need
3596 to create the nest of variant parts from the old nest. */
3598 {
3599 tree new_variant_part
3605 }
3607 /* Now go through the entities again looking for Itypes that
3608 we have not elaborated but should (e.g., Etypes of fields
3609 that have Original_Components). */
3617 /* Do not emit debug info for the type yet since we're going to
3618 modify it below. */
3623 /* See the E_Record_Type case for the rationale. */
3630 /* Fill in locations of fields. */
3633 /* If debugging information is being written for the type, write
3634 a record that shows what we are a subtype of and also make a
3635 variable that indicates our size, if still variable. */
3637 {
3639 tree gnu_unpad_base_name
3647 build_reference_type
3649 gnu_subtype_marker,
3664 gnat_entity);
3665 }
3670 /* Now we can finalize it. */
3672 }
3674 /* Otherwise, go down all the components in the new type and make
3675 them equivalent to those in the base type. */
3676 else
3677 {
3687 gnat_to_gnu_field_decl
3690 }
3691 }
3695 /* Use the special descriptor type for dispatch tables if needed,
3696 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3697 Note that we are only required to do so for static tables in
3698 order to be compatible with the C++ ABI, but Ada 2005 allows
3699 to extend library level tagged types at the local level so
3700 we do it in the non-static case as well. */
3703 {
3707 }
3709 /* ... fall through ... */
3712 /* If we are not defining this entity, and we have incomplete
3713 entities being processed above us, make a dummy type and
3714 fill it in later. */
3716 {
3719 gnu_type
3720 = build_pointer_type
3735 }
3737 /* ... fall through ... */
3744 {
3745 /* The designated type and its equivalent type for gigi. */
3748 /* Whether it comes from a limited with. */
3749 bool is_from_limited_with
3752 /* The "full view" of the designated type. If this is an incomplete
3753 entity from a limited with, treat its non-limited view as the full
3754 view. Otherwise, if this is an incomplete or private type, use the
3755 full view. In the former case, we might point to a private type,
3756 in which case, we need its full view. Also, we want to look at the
3757 actual type used for the representation, so this takes a total of
3758 three steps. */
3759 Entity_Id gnat_desig_full_direct_first
3760 = (is_from_limited_with
3764 Entity_Id gnat_desig_full_direct
3765 = ((is_from_limited_with
3770 Entity_Id gnat_desig_full
3772 /* The type actually used to represent the designated type, either
3773 gnat_desig_full or gnat_desig_equiv. */
3774 Entity_Id gnat_desig_rep;
3775 /* True if this is a pointer to an unconstrained array. */
3777 /* We want to know if we'll be seeing the freeze node for any
3778 incomplete type we may be pointing to. */
3779 bool in_main_unit
3783 /* True if we make a dummy type here. */
3785 /* The mode to be used for the pointer type. */
3787 /* The GCC type used for the designated type. */
3793 /* If either the designated type or its full view is an unconstrained
3794 array subtype, replace it with the type it's a subtype of. This
3795 avoids problems with multiple copies of unconstrained array types.
3796 Likewise, if the designated type is a subtype of an incomplete
3797 record type, use the parent type to avoid order of elaboration
3798 issues. This can lose some code efficiency, but there is no
3799 alternative. */
3810 /* Set the type that's actually the representation of the designated
3811 type and also flag whether we have a unconstrained array. */
3812 gnat_desig_rep
3814 is_unconstrained_array
3817 /* If we are pointing to an incomplete type whose completion is an
3818 unconstrained array, make dummy fat and thin pointer types to it.
3819 Likewise if the type itself is dummy or an unconstrained array. */
3823 && TYPE_IS_DUMMY_P
3825 || (!in_main_unit
3828 || (in_main_unit
3829 && is_from_limited_with
3831 {
3834 else
3835 {
3838 }
3840 /* If the call above got something that has a pointer, the pointer
3841 is our type. This could have happened either because the type
3842 was elaborated or because somebody else executed the code. */
3846 }
3848 /* If we already know what the full type is, use it. */
3853 /* Get the type of the thing we are to point to and build a pointer to
3854 it. If it is a reference to an incomplete or private type with a
3855 full view that is a record, make a dummy type node and get the
3856 actual type later when we have verified it is safe. */
3862 /* Likewise if we are pointing to a record or array and we are
3863 to defer elaborating incomplete types. We do this as this
3864 access type may be the full view of a private type. Note
3865 that the unconstrained array case is handled above. */
3871 /* If this is a reference from a limited_with type back to our
3872 main unit and there's a freeze node for it, either we have
3873 already processed the declaration and made the dummy type,
3874 in which case we just reuse the latter, or we have not yet,
3875 in which case we make the dummy type and it will be reused
3876 when the declaration is finally processed. In both cases,
3877 the pointer eventually created below will be automatically
3878 adjusted when the freeze node is processed. Note that the
3879 unconstrained array case is handled above. */
3880 || (in_main_unit
3881 && is_from_limited_with
3883 {
3886 }
3888 /* Otherwise handle the case of a pointer to itself. */
3890 {
3891 gnu_type
3895 }
3897 /* If expansion is disabled, the equivalent type of a concurrent type
3898 is absent, so build a dummy pointer type. */
3902 /* Finally, handle the default case where we can just elaborate our
3903 designated type. */
3904 else
3907 /* It is possible that a call to gnat_to_gnu_type above resolved our
3908 type. If so, just return it. */
3910 {
3913 }
3915 /* If we haven't done it yet, build the pointer type the usual way. */
3917 {
3918 /* Modify the designated type if we are pointing only to constant
3919 objects, but don't do it for unconstrained arrays. */
3922 {
3923 gnu_desig_type
3924 = build_qualified_type
3928 /* Some extra processing is required if we are building a
3929 pointer to an incomplete type (in the GCC sense). We might
3930 have such a type if we just made a dummy, or directly out
3931 of the call to gnat_to_gnu_type above if we are processing
3932 an access type for a record component designating the
3933 record type itself. */
3935 {
3936 /* We must ensure that the pointer to variant we make will
3937 be processed by update_pointer_to when the initial type
3938 is completed. Pretend we made a dummy and let further
3939 processing act as usual. */
3942 /* We must ensure that update_pointer_to will not retrieve
3943 the dummy variant when building a properly qualified
3944 version of the complete type. We take advantage of the
3945 fact that get_qualified_type is requiring TYPE_NAMEs to
3946 match to influence build_qualified_type and then also
3947 update_pointer_to here. */
3950 }
3951 }
3953 gnu_type
3956 }
3958 /* If we are not defining this object and we have made a dummy pointer,
3959 save our current definition, evaluate the actual type, and replace
3960 the tentative type we made with the actual one. If we are to defer
3961 actually looking up the actual type, make an entry in the deferred
3962 list. If this is from a limited with, we may have to defer to the
3963 end of the current unit. */
3965 {
3966 tree gnu_old_desig_type;
3969 {
3972 gnu_type = build_pointer_type
3974 }
3975 else
3987 /* Note that the call to gnat_to_gnu_type on gnat_desig_equiv might
3988 update gnu_old_desig_type directly, in which case it will not be
3989 a dummy type any more when we get into update_pointer_to.
3991 This can happen e.g. when the designated type is a record type,
3992 because their elaboration starts with an initial node from
3993 make_dummy_type, which may be the same node as the one we got.
3995 Besides, variants of this non-dummy type might have been created
3996 along the way. update_pointer_to is expected to properly take
3997 care of those situations. */
3999 {
4002 }
4003 else
4004 {
4007 = (is_from_limited_with
4013 }
4014 }
4015 }
4022 else
4023 {
4024 /* The run-time representation is the equivalent type. */
4027 }
4040 /* We treat this as identical to its base type; any constraint is
4041 meaningful only to the front-end.
4043 The designated type must be elaborated as well, if it does
4044 not have its own freeze node. Designated (sub)types created
4045 for constrained components of records with discriminants are
4046 not frozen by the front-end and thus not elaborated by gigi,
4047 because their use may appear before the base type is frozen,
4048 and because it is not clear that they are needed anywhere in
4049 gigi. With the current model, there is no correct place where
4050 they could be elaborated. */
4057 {
4058 /* If we are not defining this entity, and we have incomplete
4059 entities being processed above us, make a dummy type and
4060 elaborate it later. */
4062 {
4065 p->old_type
4070 }
4073 Incomplete_Or_Private_Kind))
4076 }
4081 /* Subprogram Entities
4083 The following access functions are defined for subprograms:
4085 Etype Return type or Standard_Void_Type.
4086 First_Formal The first formal parameter.
4087 Is_Imported Indicates that the subprogram has appeared in
4088 an INTERFACE or IMPORT pragma. For now we
4089 assume that the external language is C.
4090 Is_Exported Likewise but for an EXPORT pragma.
4091 Is_Inlined True if the subprogram is to be inlined.
4093 Each parameter is first checked by calling must_pass_by_ref on its
4094 type to determine if it is passed by reference. For parameters which
4095 are copied in, if they are Ada In Out or Out parameters, their return
4096 value becomes part of a record which becomes the return type of the
4097 function (C function - note that this applies only to Ada procedures
4098 so there is no Ada return type). Additional code to store back the
4099 parameters will be generated on the caller side. This transformation
4100 is done here, not in the front-end.
4102 The intended result of the transformation can be seen from the
4103 equivalent source rewritings that follow:
4105 struct temp {int a,b};
4106 procedure P (A,B: In Out ...) is temp P (int A,B)
4107 begin {
4108 .. ..
4109 end P; return {A,B};
4110 }
4112 temp t;
4113 P(X,Y); t = P(X,Y);
4114 X = t.a , Y = t.b;
4116 For subprogram types we need to perform mainly the same conversions to
4117 GCC form that are needed for procedures and function declarations. The
4118 only difference is that at the end, we make a type declaration instead
4119 of a function declaration. */
4124 {
4125 /* The type returned by a function or else Standard_Void_Type for a
4126 procedure. */
4128 tree gnu_return_type;
4129 /* The first GCC parameter declaration (a PARM_DECL node). The
4130 PARM_DECL nodes are chained through the DECL_CHAIN field, so this
4131 actually is the head of this parameter list. */
4133 /* Likewise for the stub associated with an exported procedure. */
4135 /* Non-null for subprograms containing parameters passed by copy-in
4136 copy-out (Ada In Out or Out parameters not passed by reference),
4137 in which case it is the list of nodes used to specify the values
4138 of the In Out/Out parameters that are returned as a record upon
4139 procedure return. The TREE_PURPOSE of an element of this list is
4140 a field of the record and the TREE_VALUE is the PARM_DECL
4141 corresponding to that field. This list will be saved in the
4142 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
4144 /* List of fields in return type of procedure with copy-in copy-out
4145 parameters. */
4147 /* If an import pragma asks to map this subprogram to a GCC builtin,
4148 this is the builtin DECL node. */
4150 /* For the stub associated with an exported procedure. */
4153 Entity_Id gnat_param;
4154 enum inline_status_t inline_status
4156 ? is_suppressed
4159 bool extern_flag
4162 /* The semantics of "pure" in Ada essentially matches that of "const"
4163 in the back-end. In particular, both properties are orthogonal to
4164 the "nothrow" property if the EH circuitry is explicit in the
4165 internal representation of the back-end. If we are to completely
4166 hide the EH circuitry from it, we need to declare that calls to pure
4167 Ada subprograms that can throw have side effects since they can
4168 trigger an "abnormal" transfer of control flow; thus they can be
4169 neither "const" nor "pure" in the back-end sense. */
4170 bool const_flag
4180 /* A parameter may refer to this type, so defer completion of any
4181 incomplete types. */
4183 {
4184 defer_incomplete_level++;
4186 }
4188 /* If the subprogram has an alias, it is probably inherited, so
4189 we can use the original one. If the original "subprogram"
4190 is actually an enumeration literal, it may be the first use
4191 of its type, so we must elaborate that type now. */
4193 {
4199 /* Elaborate any Itypes in the parameters of this entity. */
4207 }
4209 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
4210 corresponding DECL node. Proper generation of calls later on need
4211 proper parameter associations so we don't "break;" here. */
4214 {
4217 /* Inability to find the builtin decl most often indicates a
4218 genuine mistake, but imports of unregistered intrinsics are
4219 sometimes issued on purpose to allow hooking in alternate
4220 bodies. We post a warning conditioned on Wshadow in this case,
4221 to let developers be notified on demand without risking false
4222 positives with common default sets of options. */
4226 }
4228 /* ??? What if we don't find the builtin node above ? warn ? err ?
4229 In the current state we neither warn nor err, and calls will just
4230 be handled as for regular subprograms. */
4232 /* Look into the return type and get its associated GCC tree. If it
4233 is not void, compute various flags for the subprogram type. */
4236 else
4237 {
4238 /* Ada 2012 (AI05-0151): Incomplete types coming from a limited
4239 context may now appear in parameter and result profiles. If
4240 we are only annotating types, break circularities here. */
4244 && In_Extended_Main_Code_Unit
4248 else
4251 /* If this function returns by reference, make the actual return
4252 type the pointer type and make a note of that. */
4254 {
4257 }
4259 /* If we are supposed to return an unconstrained array type, make
4260 the actual return type the fat pointer type. */
4262 {
4265 }
4267 /* Likewise, if the return type requires a transient scope, the
4268 return value will be allocated on the secondary stack so the
4269 actual return type is the pointer type. */
4271 {
4274 }
4276 /* If the Mechanism is By_Reference, ensure this function uses the
4277 target's by-invisible-reference mechanism, which may not be the
4278 same as above (e.g. it might be passing an extra parameter). */
4283 /* Likewise, if the return type is itself By_Reference. */
4287 /* If the type is a padded type and the underlying type would not
4288 be passed by reference or the function has a foreign convention,
4289 return the underlying type. */
4291 && (!default_pass_by_ref
4296 /* If the return type is unconstrained, that means it must have a
4297 maximum size. Use the padded type as the effective return type.
4298 And ensure the function uses the target's by-invisible-reference
4299 mechanism to avoid copying too much data when it returns. */
4301 {
4304 gnu_return_type
4310 /* Declare it now since it will never be declared otherwise.
4311 This is necessary to ensure that its subtrees are properly
4312 marked. */
4317 gnat_entity);
4320 }
4322 /* If the return type has a size that overflows, we cannot have
4323 a function that returns that type. This usage doesn't make
4324 sense anyway, so give an error here. */
4328 {
4330 gnat_entity);
4336 }
4337 }
4339 /* Loop over the parameters and get their associated GCC tree. While
4340 doing this, build a copy-in copy-out structure if we need one. */
4344 {
4351 /* Ada 2012 (AI05-0151): Incomplete types coming from a limited
4352 context may now appear in parameter and result profiles. If
4353 we are only annotating types, break circularities here. */
4357 && In_Extended_Main_Code_Unit
4360 {
4363 }
4364 else
4365 {
4368 }
4370 /* Builtins are expanded inline and there is no real call sequence
4371 involved. So the type expected by the underlying expander is
4372 always the type of each argument "as is". */
4375 /* Handle the first parameter of a valued procedure specially. */
4378 /* Otherwise, see if a Mechanism was supplied that forced this
4379 parameter to be passed one way or another. */
4382 ;
4391 {
4395 mech))
4397 else
4399 }
4400 else
4401 {
4404 }
4406 /* Do not call gnat_to_gnu_param for a fake parameter type since
4407 it will try to use the real type again. */
4409 {
4412 else
4413 {
4414 gnu_param
4421 }
4422 }
4423 else
4424 gnu_param
4429 /* We are returned either a PARM_DECL or a type if no parameter
4430 needs to be passed; in either case, adjust the type. */
4433 else
4434 {
4437 }
4439 /* The failure of this assertion will very likely come from an
4440 order of elaboration issue for the type of the parameter. */
4446 {
4447 /* If it's an exported subprogram, we build a parameter list
4448 in parallel, in case we need to emit a stub for it. */
4450 {
4451 gnu_stub_param_list
4453 /* Change By_Descriptor parameter to By_Reference for
4454 the internal version of an exported subprogram. */
4456 {
4457 gnu_param
4462 }
4463 else
4465 }
4472 /* If a parameter is a pointer, this function may modify
4473 memory through it and thus shouldn't be considered
4474 a const function. Also, the memory may be modified
4475 between two calls, so they can't be CSE'ed. The latter
4476 case also handles by-ref parameters. */
4480 }
4483 {
4485 {
4488 /* If this is a function, we also need a field for the
4489 return value to be placed. */
4491 {
4492 gnu_field
4494 gnu_return_type,
4500 gnu_cico_list
4502 }
4506 /* Set a default alignment to speed up accesses. But we
4507 shouldn't increase the size of the structure too much,
4508 lest it doesn't fit in return registers anymore. */
4511 }
4513 gnu_field
4521 gnu_cico_list
4523 }
4524 }
4527 {
4528 /* If we have a CICO list but it has only one entry, we convert
4529 this function into a function that returns this object. */
4533 /* Do not finalize the return type if the subprogram is stubbed
4534 since structures are incomplete for the back-end. */
4536 {
4540 /* Try to promote the mode of the return type if it is passed
4541 in registers, again to speed up accesses. */
4544 NULL_TREE))
4545 {
4546 unsigned int size
4555 {
4563 }
4564 }
4568 }
4569 }
4571 /* Deal with platform-specific calling conventions. */
4573 prepend_one_attribute
4576 gnat_entity);
4578 prepend_one_attribute
4581 gnat_entity);
4583 /* If we should request stack realignment for a foreign convention
4584 subprogram, do so. Note that this applies to task entry points
4585 in particular. */
4588 prepend_one_attribute
4591 gnat_entity);
4593 /* Deal with a pragma Linker_Section on a subprogram. */
4599 /* The lists have been built in reverse. */
4607 || return_by_direct_ref_p
4608 || return_by_invisi_ref_p
4610 gnu_type
4613 return_by_direct_ref_p,
4614 return_by_invisi_ref_p);
4617 gnu_stub_type
4620 return_by_direct_ref_p,
4621 return_by_invisi_ref_p);
4623 /* A subprogram (something that doesn't return anything) shouldn't
4624 be considered const since there would be no reason for such a
4625 subprogram. Note that procedures with Out (or In Out) parameters
4626 have already been converted into a function with a return type. */
4630 gnu_type
4637 gnu_stub_type
4643 /* If we have a builtin decl for that function, use it. Check if the
4644 profiles are compatible and warn if they are not. The checker is
4645 expected to post extra diagnostics in this case. */
4647 {
4648 intrin_binding_t inb;
4655 post_error
4657 gnat_entity);
4662 }
4664 /* If there was no specified Interface_Name and the external and
4665 internal names of the subprogram are the same, only use the
4666 internal name to allow disambiguation of nested subprograms. */
4671 /* If we are defining the subprogram and it has an Address clause
4672 we must get the address expression from the saved GCC tree for the
4673 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4674 the address expression here since the front-end has guaranteed
4675 in that case that the elaboration has no effects. If there is
4676 an Address clause and we are not defining the object, just
4677 make it a constant. */
4679 {
4683 gnu_address
4690 /* Convert the type of the object to a reference type that can
4691 alias everything as per 13.3(19). */
4692 gnu_type
4697 gnu_decl
4702 }
4705 {
4707 gnu_decl
4710 }
4711 else
4712 {
4714 {
4719 }
4721 gnu_decl
4727 {
4728 tree gnu_stub_decl
4734 }
4736 /* This is unrelated to the stub built right above. */
4739 }
4740 }
4751 {
4752 /* Get the "full view" of this entity. If this is an incomplete
4753 entity from a limited with, treat its non-limited view as the
4754 full view. Otherwise, use either the full view or the underlying
4755 full view, whichever is present. This is used in all the tests
4756 below. */
4757 Entity_Id full_view
4764 /* If this is an incomplete type with no full view, it must be a Taft
4765 Amendment type, in which case we return a dummy type. Otherwise,
4766 just get the type from its Etype. */
4768 {
4770 {
4773 }
4774 else
4775 {
4779 }
4781 }
4783 /* If we already made a type for the full view, reuse it. */
4785 {
4788 }
4790 /* Otherwise, if we are not defining the type now, get the type
4791 from the full view. But always get the type from the full view
4792 for define on use types, since otherwise we won't see them! */
4796 {
4800 }
4802 /* For incomplete types, make a dummy type entry which will be
4803 replaced later. Save it as the full declaration's type so
4804 we can do any needed updates when we see it. */
4811 }
4814 /* Class-wide types are always transformed into their root type. */
4823 /* Concurrent types are always transformed into their record type. */
4826 else
4837 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4838 we've already saved it, so we don't try to. */
4844 /* This is a SPARK annotation that only reaches here when compiling in
4845 ASIS mode and has no characteristics to annotate. */
4851 }
4853 /* If we had a case where we evaluated another type and it might have
4854 defined this one, handle it here. */
4856 {
4859 }
4861 /* If we are processing a type and there is either no decl for it or
4862 we just made one, do some common processing for the type, such as
4863 handling alignment and possible padding. */
4865 {
4866 /* Process the attributes, if not already done. Note that the type is
4867 already defined so we cannot pass true for IN_PLACE here. */
4870 /* Tell the middle-end that objects of tagged types are guaranteed to
4871 be properly aligned. This is necessary because conversions to the
4872 class-wide type are translated into conversions to the root type,
4873 which can be less aligned than some of its derived types. */
4878 /* Record whether the type is passed by reference. */
4882 /* ??? Don't set the size for a String_Literal since it is either
4883 confirming or we don't handle it properly (if the low bound is
4884 non-constant). */
4886 {
4889 gnu_size
4892 }
4894 /* If a size was specified, see if we can make a new type of that size
4895 by rearranging the type, for example from a fat to a thin pointer. */
4897 {
4898 gnu_type
4905 }
4907 /* If the alignment hasn't already been processed and this is
4908 not an unconstrained array, see if an alignment is specified.
4909 If not, we pick a default alignment for atomic objects. */
4911 ;
4913 {
4917 /* Warn on suspiciously large alignments. This should catch
4918 errors about the (alignment,byte)/(size,bit) discrepancy. */
4920 {
4921 tree size;
4923 /* If a size was specified, take it into account. Otherwise
4924 use the RM size for records or unions as the type size has
4925 already been adjusted to the alignment. */
4931 else
4934 /* Consider an alignment as suspicious if the alignment/size
4935 ratio is greater or equal to the byte/bit ratio. */
4940 gnat_entity);
4941 }
4942 }
4953 /* See if we need to pad the type. If we did, and made a record,
4954 the name of the new type may be changed. So get it back for
4955 us when we make the new TYPE_DECL below. */
4963 /* Now set the RM size of the type. We cannot do it before padding
4964 because we need to accept arbitrary RM sizes on integral types. */
4967 /* If we are at global level, GCC will have applied variable_size to
4968 the type, but that won't have done anything. So, if it's not
4969 a constant or self-referential, call elaborate_expression_1 to
4970 make a variable for the size rather than calculating it each time.
4971 Handle both the RM size and the actual size. */
4976 {
4984 /* ??? For now, store the size as a multiple of the alignment in
4985 bytes so that we can see the alignment from the tree. */
4992 /* ??? gnu_type may come from an existing type so the MULT_EXPR node
4993 may not be marked by the call to create_type_decl below. */
4997 {
5002 {
5006 /* If the position of the variant part is constant, subtract
5007 it from the size of the type of the parent to get the new
5008 size. This manual CSE reduces the data size. */
5010 {
5018 }
5019 else
5020 {
5023 gnat_entity,
5027 /* ??? For now, store the size as a multiple of the
5028 alignment in bytes so that we can see the alignment
5029 from the tree. */
5032 gnat_entity,
5033 get_identifier
5038 /* ??? For now, store the offset as a multiple of the
5039 alignment in bytes so that we can see the alignment
5040 from the tree. */
5043 gnat_entity,
5046 DECL_OFFSET_ALIGN
5048 }
5052 }
5056 else
5057 ada_size
5062 }
5063 }
5065 /* If this is a record type or subtype, call elaborate_expression_2 on
5066 any field position. Do this for both global and local types.
5067 Skip any fields that we haven't made trees for to avoid problems with
5068 class wide types. */
5073 {
5076 /* ??? For now, store the offset as a multiple of the alignment
5077 in bytes so that we can see the alignment from the tree. */
5079 {
5082 gnat_temp,
5087 /* ??? The context of gnu_field is not necessarily gnu_type
5088 so the MULT_EXPR node built above may not be marked by
5089 the call to create_type_decl below. */
5092 }
5093 }
5096 gnu_type
5113 else
5114 {
5117 }
5118 }
5121 {
5124 /* If this is a derived type, relate its alias set to that of its parent
5125 to avoid troubles when a call to an inherited primitive is inlined in
5126 a context where a derived object is accessed. The inlined code works
5127 on the parent view so the resulting code may access the same object
5128 using both the parent and the derived alias sets, which thus have to
5129 conflict. As the same issue arises with component references, the
5130 parent alias set also has to conflict with composite types enclosing
5131 derived components. For instance, if we have:
5133 type D is new T;
5134 type R is record
5135 Component : D;
5136 end record;
5138 we want T to conflict with both D and R, in addition to R being a
5139 superset of D by record/component construction.
5141 One way to achieve this is to perform an alias set copy from the
5142 parent to the derived type. This is not quite appropriate, though,
5143 as we don't want separate derived types to conflict with each other:
5145 type I1 is new Integer;
5146 type I2 is new Integer;
5148 We want I1 and I2 to both conflict with Integer but we do not want
5149 I1 to conflict with I2, and an alias set copy on derivation would
5150 have that effect.
5152 The option chosen is to make the alias set of the derived type a
5153 superset of that of its parent type. It trivially fulfills the
5154 simple requirement for the Integer derivation example above, and
5155 the component case as well by superset transitivity:
5157 superset superset
5158 R ----------> D ----------> T
5160 However, for composite types, conversions between derived types are
5161 translated into VIEW_CONVERT_EXPRs so a sequence like:
5163 type Comp1 is new Comp;
5164 type Comp2 is new Comp;
5165 procedure Proc (C : Comp1);
5167 C : Comp2;
5168 Proc (Comp1 (C));
5170 is translated into:
5172 C : Comp2;
5173 Proc ((Comp1 &) &VIEW_CONVERT_EXPR <Comp1> (C));
5175 and gimplified into:
5177 C : Comp2;
5178 Comp1 *C.0;
5179 C.0 = (Comp1 *) &C;
5180 Proc (C.0);
5182 i.e. generates code involving type punning. Therefore, Comp1 needs
5183 to conflict with Comp2 and an alias set copy is required.
5185 The language rules ensure the parent type is already frozen here. */
5187 {
5192 }
5194 /* Back-annotate the Alignment of the type if not already in the
5195 tree. Likewise for sizes. */
5197 {
5201 /* If the default alignment of "double" or larger scalar types is
5202 specifically capped and this is not an array with an alignment
5203 clause on the component type, return the cap. */
5205 is_capped_double
5208 is_capped_double
5210 else
5215 else
5219 }
5222 {
5225 /* If the size is self-referential, annotate the maximum value. */
5229 /* If we are just annotating types and the type is tagged, the tag
5230 and the parent components are not generated by the front-end so
5231 sizes must be adjusted if there is no representation clause. */
5237 {
5239 Uint uint_size;
5242 {
5246 }
5247 else
5251 offset
5259 }
5260 else
5262 }
5266 }
5268 /* If we really have a ..._DECL node, set a couple of flags on it. But we
5269 cannot do so if we are reusing the ..._DECL node made for an equivalent
5270 type or an alias or a renamed object as the predicates don't apply to it
5271 but to GNAT_ENTITY. */
5276 {
5282 }
5284 /* If we haven't already, associate the ..._DECL node that we just made with
5285 the input GNAT entity node. */
5289 /* If this is an enumeration or floating-point type, we were not able to set
5290 the bounds since they refer to the type. These are always static. */
5293 {
5297 /* If this is a padded type, we need to use the underlying type. */
5301 /* If this is a floating point type and we haven't set a floating
5302 point type yet, use this in the evaluation of the bounds. */
5310 {
5311 /* Enumeration types have specific RM bounds. */
5314 }
5315 else
5316 {
5317 /* Floating-point types don't have specific RM bounds. */
5320 }
5321 }
5323 /* If we deferred processing of incomplete types, re-enable it. If there
5324 were no other disables and we have deferred types to process, do so. */
5328 {
5331 /* We are back to level 0 for the deferring of incomplete types.
5332 But processing these incomplete types below may itself require
5333 deferring, so preserve what we have and restart from scratch. */
5338 {
5345 }
5346 }
5348 /* If we are not defining this type, see if it's on one of the lists of
5349 incomplete types. If so, handle the list entry now. */
5351 {
5356 {
5360 }
5364 {
5368 }
5369 }
5372 force_global--;
5374 /* If this is a packed array type whose original array type is itself
5375 an Itype without freeze node, make sure the latter is processed. */
5383 }
5385 /* Similar, but if the returned value is a COMPONENT_REF, return the
5386 FIELD_DECL. */
5388 tree
5390 {
5397 }
5399 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5400 the GCC type corresponding to that entity. */
5402 tree
5404 {
5405 tree gnu_decl;
5407 /* The back end never attempts to annotate generic types. */
5415 }
5417 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5418 the unpadded version of the GCC type corresponding to that entity. */
5420 tree
5422 {
5429 }
5431 /* Return the DECL associated with the public subprogram GNAT_ENTITY but whose
5432 type has been changed to that of the parameterless procedure, except if an
5433 alias is already present, in which case it is returned instead. */
5435 tree
5437 {
5441 /* See the E_Function/E_Procedure case of gnat_to_gnu_entity for the model
5442 of the handling applied here. */
5445 {
5449 }
5457 gnat_entity);
5461 gnat_entity);
5466 return
5469 }
5471 /* Return whether the E_Subprogram_Type/E_Function/E_Procedure GNAT_ENTITY is
5472 a C++ imported method or equivalent.
5474 We use the predicate on 32-bit x86/Windows to find out whether we need to
5475 use the "thiscall" calling convention for GNAT_ENTITY. This convention is
5476 used for C++ methods (functions with METHOD_TYPE) by the back-end. */
5478 bool
5480 {
5484 /* This is the main case: C++ method imported as a primitive operation. */
5488 /* A thunk needs to be handled like its associated primitive operation. */
5492 /* C++ classes with no virtual functions can be imported as limited
5493 record types, but we need to return true for the constructors. */
5497 /* This is set on the E_Subprogram_Type built for a dispatching call. */
5502 }
5504 /* Finalize the processing of From_Limited_With incomplete types. */
5506 void
5508 {
5515 {
5522 }
5523 }
5525 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
5526 kind of type (such E_Task_Type) that has a different type which Gigi
5527 uses for its representation. If the type does not have a special type
5528 for its representation, return GNAT_ENTITY. If a type is supposed to
5529 exist, but does not, abort unless annotating types, in which case
5530 return Empty. If GNAT_ENTITY is Empty, return Empty. */
5532 Entity_Id
5534 {
5541 {
5565 }
5570 }
5572 /* Return a GCC tree for a type corresponding to the component type of the
5573 array type or subtype GNAT_ARRAY. DEFINITION is true if this component
5574 is for an array being defined. DEBUG_INFO_P is true if we need to write
5575 debug information for other types that we may create in the process. */
5577 static tree
5580 {
5583 tree gnu_comp_size;
5585 /* Try to get a smaller form of the component if needed. */
5599 /* Get and validate any specified Component_Size. */
5600 gnu_comp_size
5605 /* If the array has aliased components and the component size can be zero,
5606 force at least unit size to ensure that the components have distinct
5607 addresses. */
5613 gnu_comp_size
5616 /* If the component type is a RECORD_TYPE that has a self-referential size,
5617 then use the maximum size for the component size. */
5623 /* Honor the component size. This is not needed for bit-packed arrays. */
5625 {
5629 /* If an alignment is specified, use it as a cap on the component type
5630 so that it can be honored for the whole type. But ignore it for the
5631 original type of packed array types. */
5634 else
5640 else
5646 /* If a padding record was made, declare it now since it will never be
5647 declared otherwise. This is necessary to ensure that its subtrees
5648 are properly marked. */
5651 gnat_array);
5652 }
5655 gnu_type
5660 }
5662 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
5663 using MECH as its passing mechanism, to be placed in the parameter
5664 list built for GNAT_SUBPROG. Assume a foreign convention for the
5665 latter if FOREIGN is true. Also set CICO to true if the parameter
5666 must use the copy-in copy-out implementation mechanism.
5668 The returned tree is a PARM_DECL, except for those cases where no
5669 parameter needs to be actually passed to the subprogram; the type
5670 of this "shadow" parameter is then returned instead. */
5672 static tree
5675 {
5680 /* The parameter can be indirectly modified if its address is taken. */
5684 tree gnu_param;
5686 /* Copy-return is used only for the first parameter of a valued procedure.
5687 It's a copy mechanism for which a parameter is never allocated. */
5689 {
5693 }
5695 /* If this is either a foreign function or if the underlying type won't
5696 be passed by reference, strip off possible padding type. */
5698 {
5702 || foreign
5706 }
5708 /* If this is a read-only parameter, make a variant of the type that is
5709 read-only. ??? However, if this is an unconstrained array, that type
5710 can be very complex, so skip it for now. Likewise for any other
5711 self-referential type. */
5719 /* For foreign conventions, pass arrays as pointers to the element type.
5720 First check for unconstrained array and get the underlying array. */
5722 gnu_param_type
5725 /* For GCC builtins, pass Address integer types as (void *) */
5731 /* VMS descriptors are themselves passed by reference. */
5734 gnu_param_type
5737 gnat_subprog));
5739 {
5740 /* Build both a 32-bit and 64-bit descriptor, one of which will be
5741 chosen in fill_vms_descriptor. */
5742 gnu_param_type_alt
5745 gnat_subprog));
5746 gnu_param_type
5749 gnat_subprog));
5750 }
5752 /* Arrays are passed as pointers to element type for foreign conventions. */
5756 {
5757 /* Strip off any multi-dimensional entries, then strip
5758 off the last array to get the component type. */
5772 }
5774 /* Fat pointers are passed as thin pointers for foreign conventions. */
5776 gnu_param_type
5779 /* If we must pass or were requested to pass by reference, do so.
5780 If we were requested to pass by copy, do so.
5781 Otherwise, for foreign conventions, pass In Out or Out parameters
5782 or aggregates by reference. For COBOL and Fortran, pass all
5783 integer and FP types that way too. For Convention Ada, use
5784 the standard Ada default. */
5788 && ((foreign
5790 || (foreign
5795 || (!foreign
5797 {
5798 /* We take advantage of 6.2(12) by considering that references built for
5799 parameters whose type isn't by-ref and for which the mechanism hasn't
5800 been forced to by-ref are restrict-qualified in the C sense. */
5801 bool restrict_p
5805 gnu_param_type
5808 }
5810 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
5817 /* If this is an Out parameter that isn't passed by reference and isn't
5818 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
5819 it will be a VAR_DECL created when we process the procedure, so just
5820 return its type. For the special parameter of a valued procedure,
5821 never pass it in.
5823 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
5824 Out parameters with discriminants or implicit initial values to be
5825 handled like In Out parameters. These type are normally built as
5826 aggregates, hence passed by reference, except for some packed arrays
5827 which end up encoded in special integer types. Note that scalars can
5828 be given implicit initial values using the Default_Value aspect.
5830 The exception we need to make is then for packed arrays of records
5831 with discriminants or implicit initial values. We have no light/easy
5832 way to check for the latter case, so we merely check for packed arrays
5833 of records. This may lead to useless copy-in operations, but in very
5834 rare cases only, as these would be exceptions in a set of already
5835 exceptional situations. */
5837 && !by_ref
5838 && (by_return
5859 /* Save the alternate descriptor type, if any. */
5863 /* If no Mechanism was specified, indicate what we're using, then
5864 back-annotate it. */
5870 }
5872 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
5874 static bool
5876 {
5883 return
5885 }
5887 /* Return true if the array type GNU_TYPE, which represents a dimension of
5888 GNAT_TYPE, has a non-aliased component in the back-end sense. */
5890 static bool
5892 {
5893 /* If the array type is not the innermost dimension of the GNAT type,
5894 then it has a non-aliased component. */
5899 /* If the array type has an aliased component in the front-end sense,
5900 then it also has an aliased component in the back-end sense. */
5904 /* If this is a derived type, then it has a non-aliased component if
5905 and only if its parent type also has one. */
5907 {
5911 gnu_parent_type
5916 }
5918 /* Otherwise, rely exclusively on properties of the element type. */
5920 }
5922 /* Return true if GNAT_ADDRESS is a value known at compile-time. */
5924 static bool
5926 {
5927 /* Catch System'To_Address. */
5932 }
5934 /* Return true if GNAT_RANGE, a N_Range node, cannot be superflat, i.e. if the
5935 inequality HB >= LB-1 is true. LB and HB are the low and high bounds. */
5937 static bool
5939 {
5941 Node_Id scalar_range;
5944 /* If the low bound is not constant, try to find an upper bound. */
5953 /* If the high bound is not constant, try to find a lower bound. */
5962 /* If we have failed to find constant bounds, punt. */
5967 /* We need at least a signed 64-bit type to catch most cases. */
5973 /* If the low bound is the smallest integer, nothing can be smaller. */
5979 }
5981 /* Return true if GNU_EXPR is (essentially) the address of a CONSTRUCTOR. */
5983 static bool
5985 {
5993 }
5994 \f
5995 /* Given GNAT_ENTITY, elaborate all expressions that are required to
5996 be elaborated at the point of its definition, but do nothing else. */
5998 void
6000 {
6002 {
6009 {
6013 /* ??? Tests to avoid Constraint_Error in static expressions
6014 are needed until after the front stops generating bogus
6015 conversions on bounds of real types. */
6023 }
6030 {
6031 Node_Id gnat_discriminant_expr;
6032 Entity_Id gnat_field;
6036 gnat_discriminant_expr
6041 /* Ignore access discriminants. */
6046 }
6049 }
6050 }
6051 \f
6052 /* Return true if the size in units represented by GNU_SIZE can be handled by
6053 an allocation. If STATIC_P is true, consider only what can be done with a
6054 static allocation. */
6056 static bool
6058 {
6059 /* We can allocate a fixed size if it is a valid for the middle-end. */
6063 /* We can allocate a variable size if this isn't a static allocation. */
6064 else
6066 }
6067 \f
6068 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
6069 NAME, ARGS and ERROR_POINT. */
6071 static void
6074 tree attr_name,
6075 tree attr_args,
6076 Node_Id attr_error_point)
6077 {
6087 }
6089 /* Prepend to ATTR_LIST an entry for an attribute provided by GNAT_PRAGMA. */
6091 static void
6093 {
6098 /* Map the pragma at hand. Skip if this isn't one we know how to handle. */
6100 {
6131 }
6133 /* See what arguments we have and turn them into GCC trees for attribute
6134 handlers. These expect identifier for strings. We handle at most two
6135 arguments and static expressions only. */
6137 {
6143 {
6147 {
6151 }
6154 }
6158 {
6163 }
6164 }
6166 /* Prepend to the list. Make a list of the argument we might have, as GCC
6167 expects it. */
6169 gnu_arg1
6173 }
6175 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
6177 static void
6179 {
6180 Node_Id gnat_temp;
6182 /* Attributes are stored as Representation Item pragmas. */
6188 }
6189 \f
6190 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
6191 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
6192 return the GCC tree to use for that expression. GNU_NAME is the suffix
6193 to use if a variable needs to be created and DEFINITION is true if this
6194 is a definition of GNAT_ENTITY. If NEED_VALUE is true, we need a result;
6195 otherwise, we are just elaborating the expression for side-effects. If
6196 NEED_DEBUG is true, we need a variable for debugging purposes even if it
6197 isn't needed for code generation. */
6199 static tree
6202 {
6203 tree gnu_expr;
6205 /* If we already elaborated this expression (e.g. it was involved
6206 in the definition of a private type), use the old value. */
6210 /* If we don't need a value and this is static or a discriminant,
6211 we don't need to do anything. */
6218 /* If it's a static expression, we don't need a variable for debugging. */
6222 /* Otherwise, convert this tree to its GCC equivalent and elaborate it. */
6226 /* Save the expression in case we try to elaborate this entity again. Since
6227 it's not a DECL, don't check it. Don't save if it's a discriminant. */
6232 }
6234 /* Similar, but take a GNU expression and always return a result. */
6236 static tree
6239 {
6244 /* In most cases, we won't see a naked FIELD_DECL because a discriminant
6245 reference will have been replaced with a COMPONENT_REF when the type
6246 is being elaborated. However, there are some cases involving child
6247 types where we will. So convert it to a COMPONENT_REF. We hope it
6248 will be at the highest level of the expression in these cases. */
6254 /* If GNU_EXPR contains a placeholder, just return it. We rely on the fact
6255 that an expression cannot contain both a discriminant and a variable. */
6259 /* If GNU_EXPR is neither a constant nor based on a read-only variable, make
6260 a variable that is initialized to contain the expression when the package
6261 containing the definition is elaborated. If this entity is defined at top
6262 level, replace the expression by the variable; otherwise use a SAVE_EXPR
6263 if this is necessary. */
6266 else
6267 {
6268 /* Skip any conversions and simple constant arithmetics to see if the
6269 expression is based on a read-only variable.
6270 ??? This really should remain read-only, but we have to think about
6271 the typing of the tree here. */
6277 {
6279 tree offset;
6285 /* If the offset is variable, err on the side of caution. */
6288 }
6290 expr_variable_p
6291 = !(inner
6294 }
6296 /* We only need to use the variable if we are in a global context since GCC
6297 can do the right thing in the local case. However, when not optimizing,
6298 use it for bounds of loop iteration scheme to avoid code duplication. */
6299 use_variable = expr_variable_p
6300 && (expr_global_p
6301 || (!optimize
6302 && definition
6307 /* Now create it, possibly only for debugging purposes. */
6309 {
6310 tree gnu_decl
6311 = create_var_decl_1
6318 }
6321 }
6323 /* Similar, but take an alignment factor and make it explicit in the tree. */
6325 static tree
6328 {
6330 return
6333 gnu_expr,
6334 unit_align),
6336 need_debug),
6337 unit_align);
6338 }
6339 \f
6340 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
6341 the value passed against the list of choices. */
6343 tree
6345 {
6346 Node_Id choice;
6347 Node_Id gnat_temp;
6352 {
6354 {
6359 this_test
6373 this_test
6383 /* This represents either a subtype range, an enumeration
6384 literal, or a constant Ekind says which. If an enumeration
6385 literal or constant, fall through to the next case. */
6388 {
6394 this_test
6401 }
6403 /* ... fall through ... */
6409 single);
6418 }
6421 this_test);
6422 }
6425 }
6426 \f
6427 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
6428 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
6430 static int
6432 {
6433 /* If the field contains an item of variable size, we cannot pack it
6434 because we cannot create temporaries of non-fixed size in case
6435 we need to take the address of the field. See addressable_p and
6436 the notes on the addressability issues for further details. */
6440 /* If the alignment of the record is specified and the field type
6441 is over-aligned, request Storage_Unit alignment for the field. */
6443 {
6446 else
6448 }
6451 }
6453 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
6454 placed in GNU_RECORD_TYPE.
6456 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
6457 record has Component_Alignment of Storage_Unit, -2 if the enclosing
6458 record has a specified alignment.
6460 DEFINITION is true if this field is for a record being defined.
6462 DEBUG_INFO_P is true if we need to write debug information for types
6463 that we may create in the process. */
6465 static tree
6468 {
6473 bool is_volatile
6475 bool needs_strict_alignment
6476 = (is_volatile
6480 /* If this field requires strict alignment, we cannot pack it because
6481 it would very likely be under-aligned in the record. */
6484 else
6487 /* If a size is specified, use it. Otherwise, if the record type is packed,
6488 use the official RM size. See "Handling of Type'Size Values" in Einfo
6489 for further details. */
6496 else
6499 /* If we have a specified size that is smaller than that of the field's type,
6500 or a position is specified, and the field's type is a record that doesn't
6501 require strict alignment, see if we can get either an integral mode form
6502 of the type or a smaller form. If we can, show a size was specified for
6503 the field if there wasn't one already, so we know to make this a bitfield
6504 and avoid making things wider.
6506 Changing to an integral mode form is useful when the record is packed as
6507 we can then place the field at a non-byte-aligned position and so achieve
6508 tighter packing. This is in addition required if the field shares a byte
6509 with another field and the front-end lets the back-end handle the access
6510 to the field, because GCC cannot handle non-byte-aligned BLKmode fields.
6512 Changing to a smaller form is required if the specified size is smaller
6513 than that of the field's type and the type contains sub-fields that are
6514 padded, in order to avoid generating accesses to these sub-fields that
6515 are wider than the field.
6517 We avoid the transformation if it is not required or potentially useful,
6518 as it might entail an increase of the field's alignment and have ripple
6519 effects on the outer record type. A typical case is a field known to be
6520 byte-aligned and not to share a byte with another field. */
6526 || (gnu_size
6532 {
6535 {
6539 }
6540 }
6546 {
6547 Entity_Id gnat_parent
6554 /* Ensure the position does not overlap with the parent subtype, if there
6555 is one. This test is omitted if the parent of the tagged type has a
6556 full rep clause since, in this case, component clauses are allowed to
6557 overlay the space allocated for the parent type and the front-end has
6558 checked that there are no overlapping components. */
6560 {
6565 {
6566 post_error_ne_tree
6570 }
6571 }
6573 /* If this field needs strict alignment, check that the record is
6574 sufficiently aligned and that position and size are consistent with
6575 the alignment. But don't do it if we are just annotating types and
6576 the field's type is tagged, since tagged types aren't fully laid out
6577 in this mode. Also, note that atomic implies volatile so the inner
6578 test sequences ordering is significant here. */
6581 {
6587 {
6589 post_error_ne_tree
6595 post_error_ne_tree
6601 post_error_ne_tree
6607 post_error_ne_tree
6612 else
6616 }
6621 {
6623 post_error_ne_num
6629 post_error_ne_num
6635 post_error_ne_num
6641 post_error_ne
6646 else
6650 }
6651 }
6652 }
6654 /* If the record has rep clauses and this is the tag field, make a rep
6655 clause for it as well. */
6658 {
6661 }
6663 else
6664 {
6667 /* If we are packing the record and the field is BLKmode, round the
6668 size up to a byte boundary. */
6671 }
6673 /* We need to make the size the maximum for the type if it is
6674 self-referential and an unconstrained type. In that case, we can't
6675 pack the field since we can't make a copy to align it. */
6677 && !gnu_size
6680 {
6683 }
6685 /* If a size is specified, adjust the field's type to it. */
6687 {
6688 tree orig_field_type;
6690 /* If the field's type is justified modular, we would need to remove
6691 the wrapper to (better) meet the layout requirements. However we
6692 can do so only if the field is not aliased to preserve the unique
6693 layout and if the prescribed size is not greater than that of the
6694 packed array to preserve the justification. */
6702 /* Similarly if the field's type is a misaligned integral type, but
6703 there is no restriction on the size as there is no justification. */
6709 gnu_field_type
6717 /* If a padding record was made, declare it now since it will never be
6718 declared otherwise. This is necessary to ensure that its subtrees
6719 are properly marked. */
6724 }
6726 /* Otherwise (or if there was an error), don't specify a position. */
6727 else
6733 /* Now create the decl for the field. */
6734 gnu_field
6746 }
6747 \f
6748 /* Return true if at least one member of COMPONENT_LIST needs strict
6749 alignment. */
6751 static bool
6753 {
6754 Node_Id component_decl;
6759 {
6767 }
6770 }
6772 /* Return true if TYPE is a type with variable size or a padding type with a
6773 field of variable size or a record that has a field with such a type. */
6775 static bool
6777 {
6778 tree field;
6795 }
6796 \f
6797 /* Return true if FIELD is an artificial field. */
6799 static bool
6801 {
6802 /* These fields are generated by the front-end proper. */
6806 /* These fields are generated by gigi. */
6811 }
6813 /* Return true if FIELD is a non-artificial aliased field. */
6815 static bool
6817 {
6822 }
6824 /* Return true if FIELD is a non-artificial field with self-referential
6825 size. */
6827 static bool
6829 {
6837 }
6839 /* Return true if FIELD is a non-artificial field with variable size. */
6841 static bool
6843 {
6851 }
6853 /* qsort comparer for the bit positions of two record components. */
6855 static int
6857 {
6860 const int ret
6864 }
6866 /* Structure holding information for a given variant. */
6868 {
6869 /* The record type of the variant. */
6870 tree type;
6872 /* The name of the variant. */
6873 tree name;
6875 /* The qualifier of the variant. */
6876 tree qual;
6878 /* Whether the variant has a rep clause. */
6881 /* Whether the variant is packed. */
6886 /* Translate and chain the GNAT_COMPONENT_LIST to the GNU_FIELD_LIST, set the
6887 result as the field list of GNU_RECORD_TYPE and finish it up. Return true
6888 if GNU_RECORD_TYPE has a rep clause which affects the layout (see below).
6889 When called from gnat_to_gnu_entity during the processing of a record type
6890 definition, the GCC node for the parent, if any, will be the single field
6891 of GNU_RECORD_TYPE and the GCC nodes for the discriminants will be on the
6892 GNU_FIELD_LIST. The other calls to this function are recursive calls for
6893 the component list of a variant and, in this case, GNU_FIELD_LIST is empty.
6895 PACKED is 1 if this is for a packed record, -1 if this is for a record
6896 with Component_Alignment of Storage_Unit, -2 if this is for a record
6897 with a specified alignment.
6899 DEFINITION is true if we are defining this record type.
6901 CANCEL_ALIGNMENT is true if the alignment should be zeroed before laying
6902 out the record. This means the alignment only serves to force fields to
6903 be bitfields, but not to require the record to be that aligned. This is
6904 used for variants.
6906 ALL_REP is true if a rep clause is present for all the fields.
6908 UNCHECKED_UNION is true if we are building this type for a record with a
6909 Pragma Unchecked_Union.
6911 ARTIFICIAL is true if this is a type that was generated by the compiler.
6913 DEBUG_INFO is true if we need to write debug information about the type.
6915 MAYBE_UNUSED is true if this type may be unused in the end; this doesn't
6916 mean that its contents may be unused as well, only the container itself.
6918 REORDER is true if we are permitted to reorder components of this type.
6920 FIRST_FREE_POS, if nonzero, is the first (lowest) free field position in
6921 the outer record type down to this variant level. It is nonzero only if
6922 all the fields down to this level have a rep clause and ALL_REP is false.
6924 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
6925 with a rep clause is to be added; in this case, that is all that should
6926 be done with such fields and the return value will be false. */
6928 static bool
6935 {
6949 /* For each component referenced in a component declaration create a GCC
6950 field and add it to the list, skipping pragmas in the GNAT list. */
6957 {
6961 /* If present, the _Parent field must have been created as the single
6962 field of the record type. Put it before any other fields. */
6964 {
6967 }
6968 else
6969 {
6973 /* If this is the _Tag field, put it before any other fields. */
6977 /* If this is the _Controller field, put it before the other
6978 fields except for the _Tag or _Parent field. */
6980 {
6983 }
6985 /* If this is a regular field, put it after the other fields. */
6986 else
6987 {
6993 /* And record information for the final layout. */
6998 }
6999 }
7002 }
7004 /* At the end of the component list there may be a variant part. */
7007 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
7008 mutually exclusive and should go in the same memory. To do this we need
7009 to treat each variant as a record whose elements are created from the
7010 component list for the variant. So here we create the records from the
7011 lists for the variants and put them all into the QUAL_UNION_TYPE.
7012 If this is an Unchecked_Union, we make a UNION_TYPE instead or
7013 use GNU_RECORD_TYPE if there are no fields so far. */
7015 {
7019 tree gnu_var_name
7030 gnu_union_name
7033 /* Reuse the enclosing union if this is an Unchecked_Union whose fields
7034 are all in the variant part, to match the layout of C unions. There
7035 is an associated check below. */
7038 else
7039 {
7040 gnu_union_type
7046 }
7048 /* If all the fields down to this level have a rep clause, find out
7049 whether all the fields at this level also have one. If so, then
7050 compute the new first free position to be passed downward. */
7053 {
7055 gnu_field;
7058 {
7061 this_first_free_pos
7063 }
7064 else
7065 {
7068 }
7069 }
7071 /* We build the variants in two passes. The bulk of the work is done in
7072 the first pass, that is to say translating the GNAT nodes, building
7073 the container types and computing the associated properties. However
7074 we cannot finish up the container types during this pass because we
7075 don't know where the variant part will be placed until the end. */
7079 {
7084 vinfo_t vinfo;
7092 /* Set the alignment of the inner type in case we need to make
7093 inner objects into bitfields, but then clear it out so the
7094 record actually gets only the alignment required. */
7098 /* Similarly, if the outer record has a size specified and all
7099 the fields have a rep clause, we can propagate the size. */
7101 {
7105 }
7107 /* Add the fields into the record type for the variant. Note that
7108 we aren't sure to really use it at this point, see below. */
7109 has_rep
7113 unchecked_union,
7115 this_first_free_pos,
7116 all_rep || this_first_free_pos
7119 /* Translate the qualifier and annotate the GNAT node. */
7123 /* Deal with packedness like in gnat_to_gnu_field. */
7125 {
7128 }
7129 else
7130 field_packed
7133 /* Push this variant onto the stack for the second pass. */
7141 /* Compute the global properties that will determine the placement of
7142 the variant part. */
7146 }
7148 /* Round up the first free position to the alignment of the variant part
7149 for the variants without rep clause. This will guarantee a consistent
7150 layout independently of the placement of the variant part. */
7154 /* In the second pass, the container types are adjusted if necessary and
7155 finished up, then the corresponding fields of the variant part are
7156 built with their qualifier, unless this is an unchecked union. */
7158 {
7162 /* If this is an Unchecked_Union whose fields are all in the variant
7163 part and we have a single field with no representation clause or
7164 placed at offset zero, use the field directly to match the layout
7165 of C unions. */
7167 && gnu_field_list
7171 {
7174 }
7175 else
7176 {
7177 /* Finalize the variant type now. We used to throw away empty
7178 record types but we no longer do that because we need them to
7179 generate complete debug info for the variant; otherwise, the
7180 union type definition will be lacking the fields associated
7181 with these empty variants. */
7183 {
7184 /* The variant part will be at offset 0 so we need to ensure
7185 that the fields are laid out starting from the first free
7186 position at this level. */
7188 tree gnu_rep_part;
7190 gnu_rep_part
7192 this_first_free_pos);
7197 }
7204 gnu_field
7206 gnu_union_type,
7207 all_rep_and_size
7216 }
7220 }
7222 /* Only make the QUAL_UNION_TYPE if there are non-empty variants. */
7224 {
7228 {
7232 }
7237 /* If GNU_UNION_TYPE is our record type, it means we must have an
7238 Unchecked_Union with no fields. Verify that and, if so, just
7239 return. */
7241 {
7243 && !gnu_field_list
7246 }
7251 /* Deal with packedness like in gnat_to_gnu_field. */
7254 else
7255 union_field_packed
7258 gnu_variant_part
7260 all_rep_and_size
7266 }
7267 }
7269 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses and, if we are
7270 permitted to reorder components, self-referential sizes or variable sizes.
7271 If they do, pull them out and put them onto the appropriate list. We have
7272 to do this in a separate pass since we want to handle the discriminants
7273 but can't play with them until we've used them in debugging data above.
7275 Similarly, pull out the fields with zero size and no rep clause, as they
7276 would otherwise modify the layout and thus very likely run afoul of the
7277 Ada semantics, which are different from those of C here.
7279 ??? If we reorder them, debugging information will be wrong but there is
7280 nothing that can be done about this at the moment. */
7283 #define MOVE_FROM_FIELD_LIST_TO(LIST) \
7284 do { \
7285 if (gnu_last) \
7286 DECL_CHAIN (gnu_last) = gnu_next; \
7287 else \
7288 gnu_field_list = gnu_next; \
7289 \
7290 DECL_CHAIN (gnu_field) = (LIST); \
7291 (LIST) = gnu_field; \
7292 } while (0)
7295 {
7299 {
7302 }
7306 {
7309 }
7312 {
7315 }
7318 {
7328 }
7331 }
7333 #undef MOVE_FROM_FIELD_LIST_TO
7337 /* If permitted, we reorder the fields as follows:
7339 1) all fixed length fields,
7340 2) all fields whose length doesn't depend on discriminants,
7341 3) all fields whose length depends on discriminants,
7342 4) the variant part,
7344 within the record and within each variant recursively. */
7346 gnu_field_list
7349 /* Otherwise, if there is an aliased field placed after a field whose length
7350 depends on discriminants, we put all the fields of the latter sort, last.
7351 We need to do this in case an object of this record type is mutable. */
7355 /* If P_REP_LIST is nonzero, this means that we are asked to move the fields
7356 in our REP list to the previous level because this level needs them in
7357 order to do a correct layout, i.e. avoid having overlapping fields. */
7361 /* Otherwise, sort the fields by bit position and put them into their own
7362 record, before the others, if we also have fields without rep clause. */
7364 {
7369 /* If all the fields have a rep clause, we can do a flat layout. */
7370 layout_with_rep = !gnu_field_list
7372 gnu_rep_type
7376 gnu_field;
7382 /* Put the fields in the list in order of increasing position, which
7383 means we start from the end. */
7386 {
7390 }
7394 else
7395 {
7398 /* If FIRST_FREE_POS is nonzero, we need to ensure that the fields
7399 without rep clause are laid out starting from this position.
7400 Therefore, we force it as a minimal size on the REP part. */
7401 gnu_rep_part
7404 /* Chain the REP part at the beginning of the field list. */
7407 }
7408 }
7410 /* Chain the variant part at the end of the field list. */
7422 /* Chain the fields with zero size at the beginning of the field list. */
7428 }
7429 \f
7430 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
7431 placed into an Esize, Component_Bit_Offset, or Component_Size value
7432 in the GNAT tree. */
7434 static Uint
7436 {
7437 TCode tcode;
7442 /* See if we've already saved the value for this node. */
7444 {
7452 }
7453 else
7456 /* If we do not return inside this switch, TCODE will be set to the
7457 code to use for a Create_Node operand and LEN (set above) will be
7458 the number of recursive calls for us to make. */
7461 {
7466 /* The only case we handle here is a simple discriminant reference. */
7468 {
7471 /* Climb up the chain of successive extensions, if any. */
7478 return
7480 }
7487 /* Now just list the operations we handle. */
7518 /* For negative values in sizetype, build NEGATE_EXPR of the opposite.
7519 Such values appear in expressions with aligning patterns. Note that,
7520 since sizetype is unsigned, we have to jump through some hoops. */
7522 {
7526 {
7529 }
7530 }
7534 /* In regular mode, inline back only if symbolic annotation is requested
7535 in order to avoid memory explosion on big discriminated record types.
7536 But not in ASIS mode, as symbolic annotation is required for DDA. */
7538 {
7542 }
7543 else
7546 /* Fall through... */
7550 }
7552 /* Now get each of the operands that's relevant for this code. If any
7553 cannot be expressed as a repinfo node, say we can't. */
7558 {
7561 else
7565 }
7569 /* Save the result in the cache. */
7571 {
7573 /* We can't assume the hash table data hasn't moved since the initial
7574 look up, so we have to search again. Allocating and inserting an
7575 entry at that point would be an alternative, but then we'd better
7576 discard the entry if we decided not to cache it. */
7583 }
7586 }
7588 /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
7589 and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
7590 size and alignment used by Gigi. Prefer SIZE over TYPE_SIZE if non-null.
7591 BY_REF is true if the object is used by reference. */
7593 void
7595 {
7597 {
7600 else
7602 }
7605 {
7614 }
7619 }
7621 /* Return first element of field list whose TREE_PURPOSE is the same as ELEM.
7622 Return NULL_TREE if there is no such element in the list. */
7624 static tree
7626 {
7628 {
7633 }
7635 }
7637 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding GCC type,
7638 set Component_Bit_Offset and Esize of the components to the position and
7639 size used by Gigi. */
7641 static void
7643 {
7644 Entity_Id gnat_field;
7645 tree gnu_list;
7647 /* We operate by first making a list of all fields and their position (we
7648 can get the size easily) and then update all the sizes in the tree. */
7649 gnu_list
7659 {
7661 gnu_list);
7663 {
7664 tree parent_offset;
7666 /* If we are just annotating types and the type is tagged, the tag
7667 and the parent components are not generated by the front-end so
7668 we need to add the appropriate offset to each component without
7669 representation clause. */
7673 {
7674 /* For a component appearing in the current extension, the
7675 offset is the size of the parent. */
7678 parent_offset
7680 bitsizetype);
7681 else
7685 parent_offset
7688 }
7689 else
7692 Set_Component_Bit_Offset
7694 annotate_value
7698 parent_offset)));
7702 }
7704 {
7705 /* If there is no entry, this is an inherited component whose
7706 position is the same as in the parent type. */
7707 Set_Component_Bit_Offset
7713 }
7714 }
7715 }
7716 \f
7717 /* Scan all fields in GNU_TYPE and return a TREE_LIST where TREE_PURPOSE is
7718 the FIELD_DECL and TREE_VALUE a TREE_VEC containing the byte position, the
7719 value to be placed into DECL_OFFSET_ALIGN and the bit position. The list
7720 of fields is flattened, except for variant parts if DO_NOT_FLATTEN_VARIANT
7721 is set to true. GNU_POS is to be added to the position, GNU_BITPOS to the
7722 bit position, OFFSET_ALIGN is the present offset alignment. GNU_LIST is a
7723 pre-existing list to be chained to the newly created entries. */
7725 static tree
7728 {
7729 tree gnu_field;
7732 gnu_field;
7734 {
7739 unsigned int our_offset_align
7748 /* Recurse on internal fields, flattening the nested fields except for
7749 those in the variant part, if requested. */
7751 {
7755 gnu_list
7759 else
7760 gnu_list
7764 }
7765 }
7768 }
7770 /* Return a list describing the substitutions needed to reflect the
7771 discriminant substitutions from GNAT_TYPE to GNAT_SUBTYPE. They can
7772 be in any order. The values in an element of the list are in the form
7773 of operands to SUBSTITUTE_IN_EXPR. DEFINITION is true if this is for
7774 a definition of GNAT_SUBTYPE. */
7778 {
7780 Entity_Id gnat_discrim;
7781 Node_Id gnat_constr;
7788 /* Ignore access discriminants. */
7790 {
7793 elaborate_expression
7799 }
7802 }
7804 /* Scan all fields in QUAL_UNION_TYPE and return a list describing the
7805 variants of QUAL_UNION_TYPE that are still relevant after applying
7806 the substitutions described in SUBST_LIST. GNU_LIST is a pre-existing
7807 list to be prepended to the newly created entries. */
7812 {
7813 tree gnu_field;
7816 gnu_field;
7818 {
7826 /* If the new qualifier is not unconditionally false, its variant may
7827 still be accessed. */
7829 {
7835 /* Recurse on the variant subpart of the variant, if any. */
7841 /* If the new qualifier is unconditionally true, the subsequent
7842 variants cannot be accessed. */
7845 }
7846 }
7849 }
7850 \f
7851 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
7852 corresponding to GNAT_OBJECT. If the size is valid, return an INTEGER_CST
7853 corresponding to its value. Otherwise, return NULL_TREE. KIND is set to
7854 VAR_DECL if we are specifying the size of an object, TYPE_DECL for the
7855 size of a type, and FIELD_DECL for the size of a field. COMPONENT_P is
7856 true if we are being called to process the Component_Size of GNAT_OBJECT;
7857 this is used only for error messages. ZERO_OK is true if a size of zero
7858 is permitted; if ZERO_OK is false, it means that a size of zero should be
7859 treated as an unspecified size. */
7861 static tree
7864 {
7865 Node_Id gnat_error_node;
7868 /* Return 0 if no size was specified. */
7872 /* Ignore a negative size since that corresponds to our back-annotation. */
7876 /* Find the node to use for error messages. */
7883 else
7886 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
7887 but cannot be represented in bitsizetype. */
7890 {
7893 gnat_object);
7894 else
7896 gnat_object);
7898 }
7900 /* Ignore a zero size if it is not permitted. */
7904 /* The size of objects is always a multiple of a byte. */
7907 {
7911 else
7915 }
7917 /* If this is an integral type or a packed array type, the front-end has
7918 already verified the size, so we need not do it here (which would mean
7919 checking against the bounds). However, if this is an aliased object,
7920 it may not be smaller than the type of the object. */
7925 /* If the object is a record that contains a template, add the size of the
7926 template to the specified size. */
7932 /* If a type needs strict alignment, a component of this type in
7933 a packed record cannot be packed and thus uses the type size. */
7936 else
7939 /* Modify the size of a discriminated type to be the maximum size. */
7943 /* If this is an access type or a fat pointer, the minimum size is that given
7944 by the smallest integral mode that's valid for pointers. */
7946 {
7951 }
7953 /* Issue an error either if the default size of the object isn't a constant
7954 or if the new size is smaller than it. */
7958 {
7960 post_error_ne_tree
7963 else
7964 post_error_ne_tree
7968 }
7971 }
7972 \f
7973 /* Similarly, but both validate and process a value of RM size. This routine
7974 is only called for types. */
7976 static void
7978 {
7979 Node_Id gnat_attr_node;
7982 /* Do nothing if no size was specified. */
7986 /* Ignore a negative size since that corresponds to our back-annotation. */
7990 /* Only issue an error if a Value_Size clause was explicitly given.
7991 Otherwise, we'd be duplicating an error on the Size clause. */
7992 gnat_attr_node
7995 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
7996 but cannot be represented in bitsizetype. */
7999 {
8002 gnat_entity);
8004 }
8006 /* Ignore a zero size unless a Value_Size clause exists, or a size clause
8007 exists, or this is an integer type, in which case the front-end will
8008 have always set it. */
8017 /* If the old size is self-referential, get the maximum size. */
8021 /* Issue an error either if the old size of the object isn't a constant or
8022 if the new size is smaller than it. The front-end has already verified
8023 this for scalar and packed array types. */
8031 && TYPE_PACKED_ARRAY_TYPE_P
8034 {
8036 post_error_ne_tree
8040 }
8042 /* Otherwise, set the RM size proper for integral types... */
8049 /* ...or the Ada size for record and union types. */
8053 }
8054 \f
8055 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
8056 a type or object whose present alignment is ALIGN. If this alignment is
8057 valid, return it. Otherwise, give an error and return ALIGN. */
8059 static unsigned int
8061 {
8064 Node_Id gnat_error_node;
8066 /* Don't worry about checking alignment if alignment was not specified
8067 by the source program and we already posted an error for this entity. */
8071 /* Post the error on the alignment clause if any. Note, for the implicit
8072 base type of an array type, the alignment clause is on the first
8073 subtype. */
8081 gnat_error_node =
8084 else
8087 /* Within GCC, an alignment is an integer, so we must make sure a value is
8088 specified that fits in that range. Also, there is an upper bound to
8089 alignments we can support/allow. */
8097 {
8101 /* If the default alignment of "double" or larger scalar types is
8102 specifically capped and the new alignment is above the cap, do
8103 not post an error and change the alignment only if there is an
8104 alignment clause; this makes it possible to have the associated
8105 GCC type overaligned by default for performance reasons. */
8107 {
8108 Entity_Id gnat_type
8110 is_capped_double
8112 }
8114 {
8115 Entity_Id gnat_type
8117 is_capped_double
8119 }
8120 else
8124 {
8127 }
8128 else
8129 {
8136 }
8137 }
8138 else
8139 {
8143 }
8146 }
8147 \f
8148 /* Verify that OBJECT, a type or decl, is something we can implement
8149 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
8150 if we require atomic components. */
8152 static void
8154 {
8156 Node_Id gnat_node;
8159 tree size;
8161 /* There are three case of what OBJECT can be. It can be a type, in which
8162 case we take the size, alignment and mode from the type. It can be a
8163 declaration that was indirect, in which case the relevant values are
8164 that of the type being pointed to, or it can be a normal declaration,
8165 in which case the values are of the decl. The code below assumes that
8166 OBJECT is either a type or a decl. */
8168 {
8169 /* If this is an anonymous base type, nothing to check. Error will be
8170 reported on the source type. */
8177 }
8179 {
8183 }
8184 else
8185 {
8189 }
8191 /* Consider all floating-point types atomic and any types that that are
8192 represented by integers no wider than a machine word. */
8199 /* For the moment, also allow anything that has an alignment equal
8200 to its size and which is smaller than a word. */
8208 {
8217 }
8222 else
8225 }
8226 \f
8228 /* Helper for the intrin compatibility checks family. Evaluate whether
8229 two types are definitely incompatible. */
8231 static bool
8233 {
8248 {
8255 /* Assume designated types are ok. We'd need to account for char * and
8256 void * variants to do better, which could rapidly get messy and isn't
8257 clearly worth the effort. */
8262 }
8265 }
8267 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8268 on the Ada/builtin argument lists for the INB binding. */
8270 static bool
8272 {
8278 /* Sequence position of the last argument we checked. */
8282 {
8286 /* If we've exhausted both lists simultaneously, we're done. */
8290 /* If one list is shorter than the other, they fail to match. */
8294 /* If we're done with the Ada args and not with the internal builtin
8295 args, or the other way around, complain. */
8298 {
8301 }
8305 {
8309 }
8311 /* Otherwise, check that types match for the current argument. */
8312 argpos ++;
8314 {
8318 }
8323 }
8326 }
8328 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8329 on the Ada/builtin return values for the INB binding. */
8331 static bool
8333 {
8337 /* Accept function imported as procedure, common and convenient. */
8342 /* If return type is Address (integer type), map it to void *. */
8346 /* Check return types compatibility otherwise. Note that this
8347 handles void/void as well. */
8349 {
8353 }
8356 }
8358 /* Check and return whether the Ada and gcc builtin profiles bound by INB are
8359 compatible. Issue relevant warnings when they are not.
8361 This is intended as a light check to diagnose the most obvious cases, not
8362 as a full fledged type compatibility predicate. It is the programmer's
8363 responsibility to ensure correctness of the Ada declarations in Imports,
8364 especially when binding straight to a compiler internal. */
8366 static bool
8368 {
8369 /* Check compatibility on return values and argument lists, each responsible
8370 for posting warnings as appropriate. Ensure use of the proper sloc for
8371 this purpose. */
8384 }
8385 \f
8386 /* Return a FIELD_DECL node modeled on OLD_FIELD. FIELD_TYPE is its type
8387 and RECORD_TYPE is the type of the parent. If SIZE is nonzero, it is the
8388 specified size for this field. POS_LIST is a position list describing
8389 the layout of OLD_FIELD and SUBST_LIST a substitution list to be applied
8390 to this layout. */
8392 static tree
8396 {
8408 /* If the position is now a constant, we can set it as the position of the
8409 field when we make it. Otherwise, we need to deal with it specially. */
8412 else
8415 new_field
8421 {
8423 /* Finalize the position. */
8432 }
8440 }
8442 /* Create the REP part of RECORD_TYPE with REP_TYPE. If MIN_SIZE is nonzero,
8443 it is the minimal size the REP_PART must have. */
8445 static tree
8447 {
8448 tree field;
8458 }
8460 /* Return the REP part of RECORD_TYPE, if any. Otherwise return NULL. */
8462 static tree
8464 {
8467 /* The REP part is the first field, internal, another record, and its name
8468 starts with an 'R'. */
8476 }
8478 /* Return the variant part of RECORD_TYPE, if any. Otherwise return NULL. */
8480 tree
8482 {
8483 tree field;
8485 /* The variant part is the only internal field that is a qualified union. */
8492 }
8494 /* Return a new variant part modeled on OLD_VARIANT_PART. VARIANT_LIST is
8495 the list of variants to be used and RECORD_TYPE is the type of the parent.
8496 POS_LIST is a position list describing the layout of fields present in
8497 OLD_VARIANT_PART and SUBST_LIST a substitution list to be applied to this
8498 layout. */
8500 static tree
8505 {
8513 /* First create the type of the variant part from that of the old one. */
8519 /* If the position of the variant part is constant, subtract it from the
8520 size of the type of the parent to get the new size. This manual CSE
8521 reduces the code size when not optimizing. */
8523 {
8533 first_bit));
8536 }
8537 else
8540 /* Now finish up the new variants and populate the union type. */
8542 {
8546 /* Skip variants that don't belong to this nesting level. */
8550 /* Retrieve the list of fields already added to the new variant. */
8554 /* If the old variant had a variant subpart, we need to create a new
8555 variant subpart and add it to the field list. */
8559 {
8560 tree new_variant_subpart
8565 }
8567 /* Finish up the new variant and create the field. No need for debug
8568 info thanks to the XVS type. */
8572 Empty);
8574 new_field
8582 }
8584 /* Finish up the union type and create the variant part. No need for debug
8585 info thanks to the XVS type. Note that we don't reverse the field list
8586 because VARIANT_LIST has been traversed in reverse order. */
8590 Empty);
8592 new_variant_part
8598 /* With multiple discriminants it is possible for an inner variant to be
8599 statically selected while outer ones are not; in this case, the list
8600 of fields of the inner variant is not flattened and we end up with a
8601 qualified union with a single member. Drop the useless container. */
8603 {
8612 }
8615 }
8617 /* Copy the size (and alignment and alias set) from OLD_TYPE to NEW_TYPE,
8618 which are both RECORD_TYPE, after applying the substitutions described
8619 in SUBST_LIST. */
8621 static void
8624 {
8648 SET_TYPE_ADA_SIZE
8652 /* Finalize the size. */
8655 }
8656 \f
8657 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a
8658 type with all size expressions that contain F in a PLACEHOLDER_EXPR
8659 updated by replacing F with R.
8661 The function doesn't update the layout of the type, i.e. it assumes
8662 that the substitution is purely formal. That's why the replacement
8663 value R must itself contain a PLACEHOLDER_EXPR. */
8665 tree
8667 {
8668 tree nt;
8673 {
8679 /* First the domain types of arrays. */
8682 {
8694 SET_TYPE_INDEX_TYPE
8698 }
8700 /* Then the subtypes. */
8703 {
8715 }
8727 /* These should never show up here. */
8731 {
8748 }
8753 {
8755 tree field;
8757 /* Start out with no fields, make new fields, and chain them
8758 in. If we haven't actually changed the type of any field,
8759 discard everything we've done and return the old type. */
8764 {
8769 {
8772 }
8776 {
8779 }
8781 /* Do the substitution inside the qualifier, if any. */
8783 {
8786 {
8789 }
8790 }
8797 }
8807 }
8811 }
8812 }
8813 \f
8814 /* Return the RM size of GNU_TYPE. This is the actual number of bits
8815 needed to represent the object. */
8817 tree
8819 {
8820 /* For integral types, we store the RM size explicitly. */
8824 /* Return the RM size of the actual data plus the size of the template. */
8827 return
8832 /* For record or union types, we store the size explicitly. */
8838 /* For other types, this is just the size. */
8840 }
8841 \f
8842 /* Return the name to be used for GNAT_ENTITY. If a type, create a
8843 fully-qualified name, possibly with type information encoding.
8844 Otherwise, return the name. */
8846 tree
8848 {
8851 }
8853 /* Return an identifier representing the external name to be used for
8854 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
8855 and the specified suffix. */
8857 tree
8859 {
8867 /* A variable using the Stdcall convention lives in a DLL. We adjust
8868 its name to use the jump table, the _imp__NAME contains the address
8869 for the NAME variable. */
8872 {
8878 }
8881 }
8883 /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
8884 string, return a new IDENTIFIER_NODE that is the concatenation of
8885 the name followed by "___" and the specified suffix. */
8887 tree
8889 {
8896 }
8898 /* Initialize data structures of the decl.c module. */
8900 void
8902 {
8903 /* Initialize the cache of annotated values. */
8904 annotate_value_cache
8906 }
8908 /* Destroy data structures of the decl.c module. */
8910 void
8912 {
8913 /* Destroy the cache of annotated values. */
8916 }