| blob | 6952060259d0bc20893d2401353cc46dcf57b5ee |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2010, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License along with GCC; see the file COPYING3. If not see *
19 * <http://www.gnu.org/licenses/>. *
20 * *
21 * GNAT was originally developed by the GNAT team at New York University. *
22 * Extensive contributions were provided by Ada Core Technologies Inc. *
23 * *
24 ****************************************************************************/
26 /* FIXME: Still need to include rtl.h here (via expr.h) because this file
27 actually generates RTL (search for gen_rtx_* in gnat_to_gnu_entity). */
28 #undef IN_GCC_FRONTEND
58 /* Convention_Stdcall should be processed in a specific way on Windows targets
59 only. The macro below is a helper to avoid having to check for a Windows
60 specific attribute throughout this unit. */
62 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
63 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
64 #else
65 #define Has_Stdcall_Convention(E) (0)
66 #endif
68 /* Stack realignment for functions with foreign conventions is provided on a
69 per back-end basis now, as it is handled by the prologue expanders and not
70 as part of the function's body any more. It might be requested by way of a
71 dedicated function type attribute on the targets that support it.
73 We need a way to avoid setting the attribute on the targets that don't
74 support it and use FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN for this purpose.
76 It is defined on targets where the circuitry is available, and indicates
77 whether the realignment is needed for 'main'. We use this to decide for
78 foreign subprograms as well.
80 It is not defined on targets where the circuitry is not implemented, and
81 we just never set the attribute in these cases.
83 Whether it is defined on all targets that would need it in theory is
84 not entirely clear. We currently trust the base GCC settings for this
85 purpose. */
87 #ifndef FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN
88 #define FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN 0
89 #endif
91 struct incomplete
92 {
94 tree old_type;
95 Entity_Id full_type;
96 };
98 /* These variables are used to defer recursively expanding incomplete types
99 while we are processing an array, a record or a subprogram type. */
103 /* This variable is used to delay expanding From_With_Type types until the
104 end of the spec. */
107 /* These variables are used to defer finalizing types. The element of the
108 list is the TYPE_DECL associated with the type. */
112 /* A hash table used to cache the result of annotate_value. */
116 enum alias_set_op
117 {
118 ALIAS_SET_COPY,
119 ALIAS_SET_SUBSET,
120 ALIAS_SET_SUPERSET
121 };
164 /* The relevant constituents of a subprogram binding to a GCC builtin. Used
165 to pass around calls performing profile compatibilty checks. */
175 \f
176 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
177 entity, return the equivalent GCC tree for that entity (a ..._DECL node)
178 and associate the ..._DECL node with the input GNAT defining identifier.
180 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
181 initial value (in GCC tree form). This is optional for a variable. For
182 a renamed entity, GNU_EXPR gives the object being renamed.
184 DEFINITION is nonzero if this call is intended for a definition. This is
185 used for separate compilation where it is necessary to know whether an
186 external declaration or a definition must be created if the GCC equivalent
187 was not created previously. The value of 1 is normally used for a nonzero
188 DEFINITION, but a value of 2 is used in special circumstances, defined in
189 the code. */
191 tree
193 {
194 /* Contains the kind of the input GNAT node. */
196 /* True if this is a type. */
198 /* True if debug info is requested for this entity. */
200 /* True if this entity is to be considered as imported. */
201 const bool imported_p
203 /* For a type, contains the equivalent GNAT node to be used in gigi. */
205 /* Temporary used to walk the GNAT tree. */
206 Entity_Id gnat_temp;
207 /* Contains the GCC DECL node which is equivalent to the input GNAT node.
208 This node will be associated with the GNAT node by calling at the end
209 of the `switch' statement. */
211 /* Contains the GCC type to be used for the GCC node. */
213 /* Contains the GCC size tree to be used for the GCC node. */
215 /* Contains the GCC name to be used for the GCC node. */
216 tree gnu_entity_name;
217 /* True if we have already saved gnu_decl as a GNAT association. */
219 /* True if we incremented defer_incomplete_level. */
221 /* True if we incremented force_global. */
223 /* True if we should check to see if elaborated during processing. */
225 /* True if we made GNU_DECL and its type here. */
227 /* Size and alignment of the GCC node, if meaningful. */
229 /* Contains the list of attributes directly attached to the entity. */
232 /* Since a use of an Itype is a definition, process it as such if it
233 is not in a with'ed unit. */
235 && is_type
239 {
240 /* Ensure that we are in a subprogram mentioned in the Scope chain of
241 this entity, our current scope is global, or we encountered a task
242 or entry (where we can't currently accurately check scoping). */
245 {
248 }
253 {
258 gnat_temp
270 && (current_function_decl
272 {
275 }
276 }
278 /* This abort means the Itype has an incorrect scope, i.e. that its
279 scope does not correspond to the subprogram it is declared in. */
281 }
283 /* If we've already processed this entity, return what we got last time.
284 If we are defining the node, we should not have already processed it.
285 In that case, we will abort below when we try to save a new GCC tree
286 for this object. We also need to handle the case of getting a dummy
287 type when a Full_View exists. */
290 {
297 {
298 gnu_decl
302 }
305 }
307 /* If this is a numeric or enumeral type, or an access type, a nonzero
308 Esize must be specified unless it was specified by the programmer. */
318 /* The RM size must be specified for all discrete and fixed-point types. */
322 /* If we get here, it means we have not yet done anything with this entity.
323 If we are not defining it, it must be a type or an entity that is defined
324 elsewhere or externally, otherwise we should have defined it already. */
326 || type_annotate_only
327 || is_type
334 /* Get the name of the entity and set up the line number and filename of
335 the original definition for use in any decl we make. */
339 /* For cases when we are not defining (i.e., we are referencing from
340 another compilation unit) public entities, show we are at global level
341 for the purpose of computing scopes. Don't do this for components or
342 discriminants since the relevant test is whether or not the record is
343 being defined. */
351 /* Handle any attributes directly attached to the entity. */
355 /* Do some common processing for types. */
357 {
358 /* Compute the equivalent type to be used in gigi. */
361 /* Machine_Attributes on types are expected to be propagated to
362 subtypes. The corresponding Gigi_Rep_Items are only attached
363 to the first subtype though, so we handle the propagation here. */
370 /* Compute a default value for the size of the type. */
373 {
381 else
386 }
387 else
389 }
392 {
394 /* If this is a use of a deferred constant without address clause,
395 get its full definition. */
399 {
400 gnu_decl
404 }
406 /* If we have an external constant that we are not defining, get the
407 expression that is was defined to represent. We may throw that
408 expression away later if it is not a constant. Do not retrieve the
409 expression if it is an aggregate or allocator, because in complex
410 instantiation contexts it may not be expanded */
420 /* Ignore deferred constant definitions without address clause since
421 they are processed fully in the front-end. If No_Initialization
422 is set, this is not a deferred constant but a constant whose value
423 is built manually. And constants that are renamings are handled
424 like variables. */
426 && !gnu_expr
430 {
434 }
436 /* Ignore constant definitions already marked with the error node. See
437 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
439 && gnu_expr
442 {
445 }
450 /* We used to special case VMS exceptions here to directly map them to
451 their associated condition code. Since this code had to be masked
452 dynamically to strip off the severity bits, this caused trouble in
453 the GCC/ZCX case because the "type" pointers we store in the tables
454 have to be static. We now don't special case here anymore, and let
455 the regular processing take place, which leaves us with a regular
456 exception data object for VMS exceptions too. The condition code
457 mapping is taken care of by the front end and the bitmasking by the
458 run-time library. */
463 {
464 /* The GNAT record where the component was defined. */
467 /* If the variable is an inherited record component (in the case of
468 extended record types), just return the inherited entity, which
469 must be a FIELD_DECL. Likewise for discriminants.
470 For discriminants of untagged records which have explicit
471 stored discriminants, return the entity for the corresponding
472 stored discriminant. Also use Original_Record_Component
473 if the record has a private extension. */
476 {
477 gnu_decl
482 }
484 /* If the enclosing record has explicit stored discriminants,
485 then it is an untagged record. If the Corresponding_Discriminant
486 is not empty then this must be a renamed discriminant and its
487 Original_Record_Component must point to the corresponding explicit
488 stored discriminant (i.e. we should have taken the previous
489 branch). */
492 {
493 /* A tagged record has no explicit stored discriminants. */
496 gnu_decl
501 }
505 {
510 }
512 /* If the enclosing record has explicit stored discriminants, then
513 it is an untagged record. If the Corresponding_Discriminant
514 is not empty then this must be a renamed discriminant and its
515 Original_Record_Component must point to the corresponding explicit
516 stored discriminant (i.e. we should have taken the first
517 branch). */
523 /* Otherwise, if we are not defining this and we have no GCC type
524 for the containing record, make one for it. Then we should
525 have made our own equivalent. */
527 {
528 /* ??? If this is in a record whose scope is a protected
529 type and we have an Original_Record_Component, use it.
530 This is a workaround for major problems in protected type
531 handling. */
538 {
539 gnu_decl
545 }
551 }
553 else
554 /* Here we have no GCC type and this is a reference rather than a
555 definition. This should never happen. Most likely the cause is
556 reference before declaration in the gnat tree for gnat_entity. */
558 }
564 /* Simple variables, loop variables, Out parameters and exceptions. */
565 object:
566 {
567 bool const_flag
582 tree gnu_object_size;
585 {
589 else
591 }
593 /* Get the type after elaborating the renamed object. */
596 /* If this is a standard exception definition, then use the standard
597 exception type. This is necessary to make sure that imported and
598 exported views of exceptions are properly merged in LTO mode. */
603 /* For a debug renaming declaration, build a pure debug entity. */
605 {
606 rtx addr;
609 /* The (MEM (CONST (0))) pattern is prescribed by STABS. */
612 else
617 }
619 /* If this is a loop variable, its type should be the base type.
620 This is because the code for processing a loop determines whether
621 a normal loop end test can be done by comparing the bounds of the
622 loop against those of the base type, which is presumed to be the
623 size used for computation. But this is not correct when the size
624 of the subtype is smaller than the type. */
628 /* Reject non-renamed objects whose type is an unconstrained array or
629 any object whose type is a dummy type or void. */
634 {
637 force_global--;
639 }
641 /* If an alignment is specified, use it if valid. Note that exceptions
642 are objects but don't have an alignment. We must do this before we
643 validate the size, since the alignment can affect the size. */
645 {
650 /* No point in changing the type if there is an address clause
651 as the final type of the object will be a reference type. */
654 else
655 gnu_type
658 }
660 /* If we are defining the object, see if it has a Size and validate it
661 if so. If we are not defining the object and a Size clause applies,
662 simply retrieve the value. We don't want to ignore the clause and
663 it is expected to have been validated already. Then get the new
664 type, if any. */
673 {
674 gnu_type
680 }
682 /* If this object has self-referential size, it must be a record with
683 a default discriminant. We are supposed to allocate an object of
684 the maximum size in this case, unless it is a constant with an
685 initializing expression, in which case we can get the size from
686 that. Note that the resulting size may still be a variable, so
687 this may end up with an indirect allocation. */
690 {
692 {
695 {
696 /* If the initializing expression is itself a constant,
697 despite having a nominal type with self-referential
698 size, we can get the size directly from it. */
700 && TYPE_IS_PADDING_P
704 || DECL_READONLY_ONCE_ELAB
707 else
708 gnu_size
710 }
711 else
713 }
714 /* We may have no GNU_EXPR because No_Initialization is
715 set even though there's an Expression. */
720 gnu_size
722 (Etype
724 else
725 {
728 }
729 }
731 /* If the size is zero byte, make it one byte since some linkers have
732 troubles with zero-sized objects. If the object will have a
733 template, that will make it nonzero so don't bother. Also avoid
734 doing that for an object renaming or an object with an address
735 clause, as we would lose useful information on the view size
736 (e.g. for null array slices) and we are not allocating the object
737 here anyway. */
750 /* If this is an object with no specified size and alignment, and
751 if either it is atomic or we are not optimizing alignment for
752 space and it is composite and not an exception, an Out parameter
753 or a reference to another object, and the size of its type is a
754 constant, set the alignment to the smallest one which is not
755 smaller than the size, with an appropriate cap. */
764 && !imported_p
768 {
769 /* No point in jumping through all the hoops needed in order
770 to support BIGGEST_ALIGNMENT if we don't really have to.
771 So we cap to the smallest alignment that corresponds to
772 a known efficient memory access pattern of the target. */
774 ? BIGGEST_ALIGNMENT
780 else
783 /* But make sure not to under-align the object. */
787 /* And honor the minimum valid atomic alignment, if any. */
788 #ifdef MINIMUM_ATOMIC_ALIGNMENT
791 #endif
792 }
794 /* If the object is set to have atomic components, find the component
795 type and validate it.
797 ??? Note that we ignore Has_Volatile_Components on objects; it's
798 not at all clear what to do in that case. */
800 {
809 }
811 /* Now check if the type of the object allows atomic access. Note
812 that we must test the type, even if this object has size and
813 alignment to allow such access, because we will be going inside
814 the padded record to assign to the object. We could fix this by
815 always copying via an intermediate value, but it's not clear it's
816 worth the effort. */
820 /* If this is an aliased object with an unconstrained nominal subtype,
821 make a type that includes the template. */
825 {
826 tree gnu_fat
829 gnu_type
833 debug_info_p);
834 }
836 #ifdef MINIMUM_ATOMIC_ALIGNMENT
837 /* If the size is a constant and no alignment is specified, force
838 the alignment to be the minimum valid atomic alignment. The
839 restriction on constant size avoids problems with variable-size
840 temporaries; if the size is variable, there's no issue with
841 atomic access. Also don't do this for a constant, since it isn't
842 necessary and can interfere with constant replacement. Finally,
843 do not do it for Out parameters since that creates an
844 size inconsistency with In parameters. */
853 #endif
855 /* Make a new type with the desired size and alignment, if needed.
856 But do not take into account alignment promotions to compute the
857 size of the object. */
864 /* If this is a renaming, avoid as much as possible to create a new
865 object. However, in several cases, creating it is required.
866 This processing needs to be applied to the raw expression so
867 as to make it more likely to rename the underlying object. */
869 {
872 /* If the renamed object had padding, strip off the reference
873 to the inner object and reset our type. */
876 /* Strip useless conversions around the object. */
878 && gnat_types_compatible_p
881 {
884 }
886 /* Case 1: If this is a constant renaming stemming from a function
887 call, treat it as a normal object whose initial value is what
888 is being renamed. RM 3.3 says that the result of evaluating a
889 function call is a constant object. As a consequence, it can
890 be the inner object of a constant renaming. In this case, the
891 renaming must be fully instantiated, i.e. it cannot be a mere
892 reference to (part of) an existing object. */
894 {
900 }
902 /* Otherwise, see if we can proceed with a stabilized version of
903 the renamed entity or if we need to make a new object. */
905 {
909 /* Case 2: If the renaming entity need not be materialized and
910 the renamed expression is something we can stabilize, use
911 that for the renaming. At the global level, we can only do
912 this if we know no SAVE_EXPRs need be made, because the
913 expression we return might be used in arbitrary conditional
914 branches so we must force the SAVE_EXPRs evaluation
915 immediately and this requires a function context. */
920 {
921 maybe_stable_expr
925 {
926 /* ??? No DECL_EXPR is created so we need to mark
927 the expression manually lest it is shared. */
936 }
938 /* The stabilization failed. Keep maybe_stable_expr
939 untouched here to let the pointer case below know
940 about that failure. */
941 }
943 /* Case 3: If this is a constant renaming and creating a
944 new object is allowed and cheap, treat it as a normal
945 object whose initial value is what is being renamed. */
947 && !Is_Composite_Type
949 ;
951 /* Case 4: Make this into a constant pointer to the object we
952 are to rename and attach the object to the pointer if it is
953 something we can stabilize.
955 From the proper scope, attached objects will be referenced
956 directly instead of indirectly via the pointer to avoid
957 subtle aliasing problems with non-addressable entities.
958 They have to be stable because we must not evaluate the
959 variables in the expression every time the renaming is used.
960 The pointer is called a "renaming" pointer in this case.
962 In the rare cases where we cannot stabilize the renamed
963 object, we just make a "bare" pointer, and the renamed
964 entity is always accessed indirectly through it. */
965 else
966 {
971 /* If the previous attempt at stabilizing failed, there
972 is no point in trying again and we reuse the result
973 without attaching it to the pointer. In this case it
974 will only be used as the initializing expression of
975 the pointer and thus needs no special treatment with
976 regard to multiple evaluations. */
978 ;
980 /* Otherwise, try to stabilize and attach the expression
981 to the pointer if the stabilization succeeds.
983 Note that this might introduce SAVE_EXPRs and we don't
984 check whether we're at the global level or not. This
985 is fine since we are building a pointer initializer and
986 neither the pointer nor the initializing expression can
987 be accessed before the pointer elaboration has taken
988 place in a correct program.
990 These SAVE_EXPRs will be evaluated at the right place
991 by either the evaluation of the initializer for the
992 non-global case or the elaboration code for the global
993 case, and will be attached to the elaboration procedure
994 in the latter case. */
995 else
996 {
997 maybe_stable_expr
1003 /* Attaching is actually performed downstream, as soon
1004 as we have a VAR_DECL for the pointer we make. */
1005 }
1008 maybe_stable_expr);
1012 }
1013 }
1014 }
1016 /* Make a volatile version of this object's type if we are to make
1017 the object volatile. We also interpret 13.3(19) conservatively
1018 and disallow any optimizations for such a non-constant object. */
1020 || (!const_flag
1023 || imported_p
1030 /* If we are defining an aliased object whose nominal subtype is
1031 unconstrained, the object is a record that contains both the
1032 template and the object. If there is an initializer, it will
1033 have already been converted to the right type, but we need to
1034 create the template if there is no initializer. */
1036 && !gnu_expr
1039 /* Beware that padding might have been introduced above. */
1042 == RECORD_TYPE
1043 && TYPE_CONTAINS_TEMPLATE_P
1045 {
1046 tree template_field
1053 NULL_TREE);
1056 }
1058 /* Convert the expression to the type of the object except in the
1059 case where the object's type is unconstrained or the object's type
1060 is a padded record whose field is of self-referential size. In
1061 the former case, converting will generate unnecessary evaluations
1062 of the CONSTRUCTOR to compute the size and in the latter case, we
1063 want to only copy the actual data. */
1068 && CONTAINS_PLACEHOLDER_P
1072 /* If this is a pointer that doesn't have an initializing expression,
1073 initialize it to NULL, unless the object is imported. */
1076 && !gnu_expr
1080 /* If we are defining the object and it has an Address clause, we must
1081 either get the address expression from the saved GCC tree for the
1082 object if it has a Freeze node, or elaborate the address expression
1083 here since the front-end has guaranteed that the elaboration has no
1084 effects in this case. */
1086 {
1088 tree gnu_address
1094 /* Ignore the size. It's either meaningless or was handled
1095 above. */
1097 /* Convert the type of the object to a reference type that can
1098 alias everything as per 13.3(19). */
1099 gnu_type
1103 const_flag
1107 /* If this is a deferred constant, the initializer is attached to
1108 the full view. */
1110 gnu_expr
1111 = gnat_to_gnu
1114 /* If we don't have an initializing expression for the underlying
1115 variable, the initializing expression for the pointer is the
1116 specified address. Otherwise, we have to make a COMPOUND_EXPR
1117 to assign both the address and the initial value. */
1120 else
1121 gnu_expr
1123 build_binary_op
1126 gnu_address),
1127 gnu_expr),
1128 gnu_address);
1129 }
1131 /* If it has an address clause and we are not defining it, mark it
1132 as an indirect object. Likewise for Stdcall objects that are
1133 imported. */
1137 {
1138 /* Convert the type of the object to a reference type that can
1139 alias everything as per 13.3(19). */
1140 gnu_type
1144 /* No point in taking the address of an initializing expression
1145 that isn't going to be used. */
1148 /* If it has an address clause whose value is known at compile
1149 time, make the object a CONST_DECL. This will avoid a
1150 useless dereference. */
1152 {
1153 Node_Id gnat_address
1157 {
1160 }
1161 }
1164 }
1166 /* If we are at top level and this object is of variable size,
1167 make the actual type a hidden pointer to the real type and
1168 make the initializer be a memory allocation and initialization.
1169 Likewise for objects we aren't defining (presumed to be
1170 external references from other packages), but there we do
1171 not set up an initialization.
1173 If the object's size overflows, make an allocator too, so that
1174 Storage_Error gets raised. Note that we will never free
1175 such memory, so we presume it never will get allocated. */
1178 || !definition
1182 || !definition
1184 {
1190 /* In case this was a aliased object whose nominal subtype is
1191 unconstrained, the pointer above will be a thin pointer and
1192 build_allocator will automatically make the template.
1194 If we have a template initializer only (that we made above),
1195 pretend there is none and rely on what build_allocator creates
1196 again anyway. Otherwise (if we have a full initializer), get
1197 the data part and feed that to build_allocator.
1199 If we are elaborating a mutable object, tell build_allocator to
1200 ignore a possibly simpler size from the initializer, if any, as
1201 we must allocate the maximum possible size in this case. */
1203 {
1208 {
1209 gnu_alloc_type
1216 else
1217 gnu_expr
1218 = build_component_ref
1222 }
1228 gnat_entity);
1230 gnu_expr
1233 }
1234 else
1235 {
1238 }
1239 }
1241 /* If this object would go into the stack and has an alignment larger
1242 than the largest stack alignment the back-end can honor, resort to
1243 a variable of "aligning type". */
1246 {
1247 /* Create the new variable. No need for extra room before the
1248 aligned field as this is in automatic storage. */
1249 tree gnu_new_type
1253 tree gnu_new_var
1258 /* Initialize the aligned field if we have an initializer. */
1260 add_stmt_with_node
1262 build_component_ref
1265 gnu_expr),
1266 gnat_entity);
1268 /* And setup this entity as a reference to the aligned field. */
1270 gnu_expr
1271 = build_unary_op
1279 }
1285 /* Convert the expression to the type of the object except in the
1286 case where the object's type is unconstrained or the object's type
1287 is a padded record whose field is of self-referential size. In
1288 the former case, converting will generate unnecessary evaluations
1289 of the CONSTRUCTOR to compute the size and in the latter case, we
1290 want to only copy the actual data. */
1295 && CONTAINS_PLACEHOLDER_P
1299 /* If this name is external or there was a name specified, use it,
1300 unless this is a VMS exception object since this would conflict
1301 with the symbol we need to export in addition. Don't use the
1302 Interface_Name if there is an address clause (see CD30005). */
1311 /* If this is an aggregate constant initialized to a constant, force it
1312 to be statically allocated. This saves an initialization copy. */
1314 && const_flag
1323 /* Now create the variable or the constant and set various flags. */
1324 gnu_decl
1328 gnat_entity);
1332 /* If we are defining an Out parameter and optimization isn't enabled,
1333 create a fake PARM_DECL for debugging purposes and make it point to
1334 the VAR_DECL. Suppress debug info for the latter but make sure it
1335 will live on the stack so that it can be accessed from within the
1336 debugger through the PARM_DECL. */
1338 {
1345 }
1347 /* If this is a renaming pointer, attach the renamed object to it and
1348 register it if we are at top level. */
1350 {
1353 {
1356 }
1357 }
1359 /* If this is a constant and we are defining it or it generates a real
1360 symbol at the object level and we are referencing it, we may want
1361 or need to have a true variable to represent it:
1362 - if optimization isn't enabled, for debugging purposes,
1363 - if the constant is public and not overlaid on something else,
1364 - if its address is taken,
1365 - if either itself or its type is aliased. */
1374 {
1375 tree gnu_corr_var
1379 gnat_entity);
1383 /* As debugging information will be generated for the variable,
1384 do not generate debugging information for the constant. */
1387 else
1389 }
1391 /* If this is a constant, even if we don't need a true variable, we
1392 may need to avoid returning the initializer in every case. That
1393 can happen for the address of a (constant) constructor because,
1394 upon dereferencing it, the constructor will be reinjected in the
1395 tree, which may not be valid in every case; see lvalue_required_p
1396 for more details. */
1400 /* If this object is declared in a block that contains a block with an
1401 exception handler, and we aren't using the GCC exception mechanism,
1402 we must force this variable in memory in order to avoid an invalid
1403 optimization. */
1408 /* If we are defining an object with variable size or an object with
1409 fixed size that will be dynamically allocated, and we are using the
1410 setjmp/longjmp exception mechanism, update the setjmp buffer. */
1423 gnat_entity);
1425 /* Back-annotate Esize and Alignment of the object if not already
1426 known. Note that we pick the values of the type, not those of
1427 the object, to shield ourselves from low-level platform-dependent
1428 adjustments like alignment promotion. This is both consistent with
1429 all the treatment above, where alignment and size are set on the
1430 type of the object and not on the object directly, and makes it
1431 possible to support all confirming representation clauses. */
1433 used_by_ref);
1434 }
1438 /* Return a TYPE_DECL for "void" that we previously made. */
1443 /* A special case: for the types Character and Wide_Character in
1444 Standard, we do not list all the literals. So if the literals
1445 are not specified, make this an unsigned type. */
1447 {
1451 /* Set TYPE_STRING_FLAG for Character and Wide_Character types.
1452 This is needed by the DWARF-2 back-end to distinguish between
1453 unsigned integer types and character types. */
1456 }
1458 {
1459 /* We have a list of enumeral constants in First_Literal. We make a
1460 CONST_DECL for each one and build into GNU_LITERAL_LIST the list to
1461 be placed into TYPE_FIELDS. Each node in the list is a TREE_LIST
1462 whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
1463 value of the literal. But when we have a regular boolean type, we
1464 simplify this a little by using a BOOLEAN_TYPE. */
1468 Entity_Id gnat_literal;
1472 else
1480 {
1481 tree gnu_value
1483 tree gnu_literal
1491 }
1496 /* Note that the bounds are updated at the end of this function
1497 to avoid an infinite recursion since they refer to the type. */
1498 }
1504 /* For integer types, just make a signed type the appropriate number
1505 of bits. */
1510 {
1511 /* For modular types, make the unsigned type of the proper number
1512 of bits and then set up the modulus, if required. */
1515 /* Packed array types are supposed to be subtypes only. */
1520 /* Get the modulus in this type. If it overflows, assume it is because
1521 it is equal to 2**Esize. Note that there is no overflow checking
1522 done on unsigned type, so we detect the overflow by looking for
1523 a modulus of zero, which is otherwise invalid. */
1527 {
1532 }
1534 /* If the upper bound is not maximal, make an extra subtype. */
1537 {
1544 }
1545 }
1554 /* For integral subtypes, we make a new INTEGER_TYPE. Note that we do
1555 not want to call create_range_type since we would like each subtype
1556 node to be distinct. ??? Historically this was in preparation for
1557 when memory aliasing is implemented, but that's obsolete now given
1558 the call to relate_alias_sets below.
1560 The TREE_TYPE field of the INTEGER_TYPE points to the base type;
1561 this fact is used by the arithmetic conversion functions.
1563 We elaborate the Ancestor_Subtype if it is not in the current unit
1564 and one of our bounds is non-static. We do this to ensure consistent
1565 naming in the case where several subtypes share the same bounds, by
1566 elaborating the first such subtype first, thus using its name. */
1575 /* Set the precision to the Esize except for bit-packed arrays. */
1580 /* This should be an unsigned type if the base type is unsigned or
1581 if the lower bound is constant and non-negative or if the type
1582 is biased. */
1587 else
1591 SET_TYPE_RM_MIN_VALUE
1599 SET_TYPE_RM_MAX_VALUE
1607 /* One of the above calls might have caused us to be elaborated,
1608 so don't blow up if so. */
1610 {
1613 }
1618 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
1622 /* Inherit our alias set from what we're a subtype of. Subtypes
1623 are not different types and a pointer can designate any instance
1624 within a subtype hierarchy. */
1627 /* For a packed array, make the original array type a parallel type. */
1632 gnat_to_gnu_type
1635 /* We have to handle clauses that under-align the type specially. */
1638 && Present
1641 {
1645 }
1647 /* If the type we are dealing with represents a bit-packed array,
1648 we need to have the bits left justified on big-endian targets
1649 and right justified on little-endian targets. We also need to
1650 ensure that when the value is read (e.g. for comparison of two
1651 such values), we only get the good bits, since the unused bits
1652 are uninitialized. Both goals are accomplished by wrapping up
1653 the modular type in an enclosing record type. */
1656 {
1659 /* Set the RM size before wrapping up the original type. */
1664 /* Create a stripped-down declaration, mainly for debugging. */
1668 /* Now save it and build the enclosing record type. */
1678 /* Propagate the alignment of the modular type to the record type,
1679 unless there is an alignment clause that under-aligns the type.
1680 This means that bit-packed arrays are given "ceil" alignment for
1681 their size by default, which may seem counter-intuitive but makes
1682 it possible to overlay them on modular types easily. */
1688 /* Don't notify the field as "addressable", since we won't be taking
1689 it's address and it would prevent create_field_decl from making a
1690 bitfield. */
1691 gnu_field
1695 /* Do not emit debug info until after the parallel type is added. */
1701 {
1702 /* Make the original array type a parallel type. */
1705 gnat_to_gnu_type
1709 }
1710 }
1712 /* If the type we are dealing with has got a smaller alignment than the
1713 natural one, we need to wrap it up in a record type and under-align
1714 the latter. We reuse the padding machinery for this purpose. */
1716 {
1719 /* Set the RM size before wrapping up the type. */
1723 /* Create a stripped-down declaration, mainly for debugging. */
1727 /* Now save it and build the enclosing record type. */
1739 /* Don't notify the field as "addressable", since we won't be taking
1740 it's address and it would prevent create_field_decl from making a
1741 bitfield. */
1742 gnu_field
1749 }
1754 /* If this is a VAX floating-point type, use an integer of the proper
1755 size. All the operations will be handled with ASM statements. */
1757 {
1762 sizetype));
1764 }
1766 /* The type of the Low and High bounds can be our type if this is
1767 a type from Standard, so set them at the end of the function. */
1775 {
1778 }
1780 {
1798 SET_TYPE_RM_MIN_VALUE
1806 SET_TYPE_RM_MAX_VALUE
1814 /* One of the above calls might have caused us to be elaborated,
1815 so don't blow up if so. */
1817 {
1820 }
1822 /* Inherit our alias set from what we're a subtype of, as for
1823 integer subtypes. */
1825 }
1828 /* Array and String Types and Subtypes
1830 Unconstrained array types are represented by E_Array_Type and
1831 constrained array types are represented by E_Array_Subtype. There
1832 are no actual objects of an unconstrained array type; all we have
1833 are pointers to that type.
1835 The following fields are defined on array types and subtypes:
1837 Component_Type Component type of the array.
1838 Number_Dimensions Number of dimensions (an int).
1839 First_Index Type of first index. */
1843 {
1845 const bool convention_fortran_p
1850 tree gnu_template_reference;
1861 /* Make a node for the array. If we are not defining the array
1862 suppress expanding incomplete types. */
1866 {
1867 defer_incomplete_level++;
1869 }
1871 /* Build the fat pointer type. Use a "void *" object instead of
1872 a pointer to the array type since we don't have the array type
1873 yet (it will reference the fat pointer via the bounds). */
1876 ptr_void_type_node,
1880 gnu_ptr_template,
1884 /* Make sure we can put this into a register. */
1887 /* Do not emit debug info for this record type since the types of its
1888 fields are still incomplete at this point. */
1892 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1893 is the fat pointer. This will be used to access the individual
1894 fields once we build them. */
1898 gnu_template_reference
1902 /* Now create the GCC type for each index and add the fields for that
1903 index to the template. */
1909 {
1911 tree gnu_index_base_type
1916 /* Make the FIELD_DECLs for the low and high bounds of this
1917 type and then make extractions of these fields from the
1918 template. */
1921 gnu_index_base_type,
1929 gnu_index_base_type,
1937 /* We can't use build_component_ref here since the template type
1938 isn't complete yet. */
1941 NULL_TREE);
1944 NULL_TREE);
1950 /* Compute the size of this dimension. See the E_Array_Subtype
1951 case below for the rationale. */
1952 gnu_high
1956 gnu_max,
1959 /* Make a range type with the new range in the Ada base type.
1960 Then make an index type with the size range in sizetype. */
1964 gnu_orig_min,
1965 gnu_orig_max),
1966 gnat_entity);
1968 /* Update the maximum size of the array in elements. */
1970 {
1972 tree gnu_min
1974 tree gnu_max
1976 tree gnu_this_max
1981 size_zero_node);
1986 else
1987 gnu_max_size
1989 }
1993 }
1996 gnu_template_fields
1999 /* Install all the fields into the template. */
2001 debug_info_p);
2004 /* Now make the array of arrays and update the pointer to the array
2005 in the fat pointer. Note that it is the first field. */
2007 debug_info_p);
2009 /* If Component_Size is not already specified, annotate it with the
2010 size of the component. */
2014 /* Compute the maximum size of the array in units and bits. */
2016 {
2022 }
2023 else
2026 /* Now build the array type. */
2028 {
2033 }
2035 /* If an alignment is specified, use it if valid. But ignore it
2036 for the original type of packed array types. If the alignment
2037 was requested with an explicit alignment clause, state so. */
2040 {
2046 }
2051 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2052 corresponding fat pointer. */
2059 /* If the maximum size doesn't overflow, use it. */
2065 {
2070 }
2076 /* Give the fat pointer type a name. If this is a packed type, tell
2077 the debugger how to interpret the underlying bits. */
2080 else
2086 /* Create the type to be used as what a thin pointer designates:
2087 a record type for the object and its template with the fields
2088 shifted to have the template at a negative offset. */
2091 debug_info_p);
2096 }
2102 /* This is the actual data type for array variables. Multidimensional
2103 arrays are implemented as arrays of arrays. Note that arrays which
2104 have sparse enumeration subtypes as index components create sparse
2105 arrays, which is obviously space inefficient but so much easier to
2106 code for now.
2108 Also note that the subtype never refers to the unconstrained array
2109 type, which is somewhat at variance with Ada semantics.
2111 First check to see if this is simply a renaming of the array type.
2112 If so, the result is the array type. */
2116 ;
2117 else
2118 {
2120 const bool convention_fortran_p
2129 /* First create the GCC type for each index and find out whether
2130 special types are needed for debugging information. */
2133 gnat_base_index
2139 {
2145 tree gnu_base_index_type
2149 tree gnu_high;
2151 /* See if the base array type is already flat. If it is, we
2152 are probably compiling an ACATS test but it will cause the
2153 code below to malfunction if we don't handle it specially. */
2157 {
2161 }
2163 /* Similarly, if one of the values overflows in sizetype and the
2164 range is null, use 1..0 for the sizetype bounds. */
2169 {
2173 }
2175 /* If the minimum and maximum values both overflow in sizetype,
2176 but the difference in the original type does not overflow in
2177 sizetype, ignore the overflow indication. */
2181 && !TREE_OVERFLOW
2184 gnu_orig_max,
2185 gnu_orig_min))))
2186 {
2190 }
2192 /* Compute the size of this dimension in the general case. We
2193 need to provide GCC with an upper bound to use but have to
2194 deal with the "superflat" case. There are three ways to do
2195 this. If we can prove that the array can never be superflat,
2196 we can just use the high bound of the index type. */
2199 /* Packed Array Types are never superflat. */
2203 /* Otherwise, if the high bound is constant but the low bound is
2204 not, we use the expression (hb >= lb) ? lb : hb + 1 for the
2205 lower bound. Note that the comparison must be done in the
2206 original type to avoid any overflow during the conversion. */
2209 {
2211 gnu_min
2214 boolean_type_node,
2215 gnu_orig_max,
2216 gnu_orig_min),
2217 gnu_min,
2219 size_one_node));
2220 }
2222 /* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
2223 in all the other cases. Note that, here as well as above,
2224 the condition used in the comparison must be equivalent to
2225 the condition (length != 0). This is relied upon in order
2226 to optimize array comparisons in compare_arrays. */
2227 else
2228 gnu_high
2231 boolean_type_node,
2232 gnu_orig_max,
2233 gnu_orig_min),
2234 gnu_max,
2236 size_one_node));
2238 /* Reuse the index type for the range type. Then make an index
2239 type with the size range in sizetype. */
2242 gnat_entity);
2244 /* Update the maximum size of the array in elements. Here we
2245 see if any constraint on the index type of the base type
2246 can be used in the case of self-referential bound on the
2247 index type of the subtype. We look for a non-"infinite"
2248 and non-self-referential bound from any type involved and
2249 handle each bound separately. */
2251 {
2254 tree gnu_base_index_base_type
2256 tree gnu_base_base_min
2259 tree gnu_base_base_max
2280 else
2281 {
2282 tree gnu_this_max
2286 gnu_base_max,
2287 gnu_base_min)),
2288 size_zero_node);
2293 else
2294 gnu_max_size
2296 }
2297 }
2299 /* We need special types for debugging information to point to
2300 the index types if they have variable bounds, are not integer
2301 types, are biased or are wider than sizetype. */
2312 }
2314 /* Then flatten: create the array of arrays. For an array type
2315 used to implement a packed array, get the component type from
2316 the original array type since the representation clauses that
2317 can affect it are on the latter. */
2320 {
2325 /* One of the above calls might have caused us to be elaborated,
2326 so don't blow up if so. */
2328 {
2331 }
2332 }
2333 else
2334 {
2336 debug_info_p);
2338 /* One of the above calls might have caused us to be elaborated,
2339 so don't blow up if so. */
2341 {
2344 }
2345 }
2347 /* Compute the maximum size of the array in units and bits. */
2349 {
2355 }
2356 else
2359 /* Now build the array type. */
2361 {
2366 }
2368 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
2372 /* If we are at file level and this is a multi-dimensional array,
2373 we need to make a variable corresponding to the stride of the
2374 inner dimensions. */
2376 {
2378 tree gnu_arr_type;
2384 {
2392 /* ??? For now, store the size as a multiple of the
2393 alignment of the element type in bytes so that we
2394 can see the alignment from the tree. */
2397 gnat_entity,
2402 /* ??? create_type_decl is not invoked on the inner types so
2403 the MULT_EXPR node built above will never be marked. */
2405 }
2406 }
2408 /* If we need to write out a record type giving the names of the
2409 bounds for debugging purposes, do it now and make the record
2410 type a parallel type. This is not needed for a packed array
2411 since the bounds are conveyed by the original array type. */
2413 && debug_info_p
2415 {
2418 tree gnu_field;
2424 {
2431 /* Make sure to reference the types themselves, and not just
2432 their names, as the debugger may fall back on them. */
2438 }
2442 }
2444 /* Otherwise, for a packed array, make the original array type a
2445 parallel type. */
2450 gnat_to_gnu_type
2458 /* If the size is self-referential and the maximum size doesn't
2459 overflow, use it. */
2461 && gnu_max_size
2466 {
2472 }
2474 /* Set our alias set to that of our base type. This gives all
2475 array subtypes the same alias set. */
2478 /* If this is a packed type, make this type the same as the packed
2479 array type, but do some adjusting in the type first. */
2481 {
2482 Entity_Id gnat_index;
2483 tree gnu_inner;
2485 /* First finish the type we had been making so that we output
2486 debugging information for it. */
2488 gnu_type
2493 /* Make it artificial only if the base type was artificial too.
2494 That's sort of "morally" true and will make it possible for
2495 the debugger to look it up by name in DWARF, which is needed
2496 in order to decode the packed array type. */
2497 gnu_decl
2503 /* Save it as our equivalent in case the call below elaborates
2504 this type again. */
2519 /* We need to attach the index type to the type we just made so
2520 that the actual bounds can later be put into a template. */
2525 {
2527 {
2528 /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
2529 TYPE_MODULUS for modular types so we make an extra
2530 subtype if necessary. */
2532 {
2533 tree gnu_subtype
2542 }
2546 #ifdef ENABLE_CHECKING
2547 /* Check for other cases of overloading. */
2549 #endif
2550 }
2555 SET_TYPE_ACTUAL_BOUNDS
2562 SET_TYPE_ACTUAL_BOUNDS
2568 }
2569 }
2571 else
2572 /* Abort if packed array with no Packed_Array_Type field set. */
2574 }
2578 /* Create the type for a string literal. */
2579 {
2580 Entity_Id gnat_full_type
2585 tree gnu_string_array_type
2587 tree gnu_string_index_type
2590 tree gnu_lower_bound
2595 tree gnu_upper_bound
2597 gnu_lower_bound,
2599 tree gnu_index_type
2603 gnu_lower_bound,
2604 gnu_upper_bound),
2605 gnat_entity);
2607 gnu_type
2609 gnu_index_type);
2613 }
2616 /* Record Types and Subtypes
2618 The following fields are defined on record types:
2620 Has_Discriminants True if the record has discriminants
2621 First_Discriminant Points to head of list of discriminants
2622 First_Entity Points to head of list of fields
2623 Is_Tagged_Type True if the record is tagged
2625 Implementation of Ada records and discriminated records:
2627 A record type definition is transformed into the equivalent of a C
2628 struct definition. The fields that are the discriminants which are
2629 found in the Full_Type_Declaration node and the elements of the
2630 Component_List found in the Record_Type_Definition node. The
2631 Component_List can be a recursive structure since each Variant of
2632 the Variant_Part of the Component_List has a Component_List.
2634 Processing of a record type definition comprises starting the list of
2635 field declarations here from the discriminants and the calling the
2636 function components_to_record to add the rest of the fields from the
2637 component list and return the gnu type node. The function
2638 components_to_record will call itself recursively as it traverses
2639 the tree. */
2643 {
2644 gnu_type
2645 = build_complex_type
2646 (get_unpadded_type
2649 (Component_List
2650 (Type_Definition
2654 }
2656 {
2659 Entity_Id gnat_field;
2661 /* Set PACKED in keeping with gnat_to_gnu_field. */
2662 int packed
2675 bool is_extension
2680 /* See if all fields have a rep clause. Stop when we find one
2681 that doesn't. */
2689 {
2692 }
2694 /* If this is a record extension, go a level further to find the
2695 record definition. Also, verify we have a Parent_Subtype. */
2697 {
2704 }
2706 /* Make a node for the record. If we are not defining the record,
2707 suppress expanding incomplete types. */
2713 {
2714 defer_incomplete_level++;
2716 }
2718 /* If both a size and rep clause was specified, put the size in
2719 the record type now so that it can get the proper mode. */
2723 /* Always set the alignment here so that it can be used to
2724 set the mode, if it is making the alignment stricter. If
2725 it is invalid, it will be checked again below. If this is to
2726 be Atomic, choose a default alignment of a word unless we know
2727 the size and it's smaller. */
2734 /* If a type needs strict alignment, the minimum size will be the
2735 type size instead of the RM size (see validate_size). Cap the
2736 alignment, lest it causes this type size to become too large. */
2739 {
2744 }
2745 else
2748 /* If we have a Parent_Subtype, make a field for the parent. If
2749 this record has rep clauses, force the position to zero. */
2751 {
2753 tree gnu_parent;
2755 /* A major complexity here is that the parent subtype will
2756 reference our discriminants in its Discriminant_Constraint
2757 list. But those must reference the parent component of this
2758 record which is of the parent subtype we have not built yet!
2759 To break the circle we first build a dummy COMPONENT_REF which
2760 represents the "get to the parent" operation and initialize
2761 each of those discriminants to a COMPONENT_REF of the above
2762 dummy parent referencing the corresponding discriminant of the
2763 base type of the parent subtype. */
2768 void_type_node),
2769 NULL_TREE);
2776 {
2777 tree gnu_field
2780 save_gnu_tree
2785 }
2787 /* Then we build the parent subtype. If it has discriminants but
2788 the type itself has unknown discriminants, this means that it
2789 doesn't contain information about how the discriminants are
2790 derived from those of the ancestor type, so it cannot be used
2791 directly. Instead it is built by cloning the parent subtype
2792 of the underlying record view of the type, for which the above
2793 derivation of discriminants has been made explicit. */
2796 {
2799 /* If we are defining the type, the underlying record
2800 view must already have been elaborated at this point.
2801 Otherwise do it now as its parent subtype cannot be
2802 technically elaborated on its own. */
2805 else
2810 /* Substitute the "get to the parent" of the type for that
2811 of its underlying record view in the cloned type. */
2816 {
2818 tree gnu_ref
2821 gnu_parent
2823 }
2824 }
2825 else
2828 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
2829 initially built. The discriminants must reference the fields
2830 of the parent subtype and not those of its base type for the
2831 placeholder machinery to properly work. */
2833 {
2834 /* The actual parent subtype is the full view. */
2836 {
2839 else
2841 }
2847 {
2857 }
2858 }
2860 /* The "get to the parent" COMPONENT_REF must be given its
2861 proper type... */
2864 /* ...and reference the _Parent field of this record. */
2865 gnu_field
2868 has_rep
2870 has_rep
2876 }
2878 /* Make the fields for the discriminants and put them into the record
2879 unless it's an Unchecked_Union. */
2884 {
2885 /* If this is a record extension and this discriminant is the
2886 renaming of another discriminant, we've handled it above. */
2891 gnu_field
2893 debug_info_p);
2895 /* Make an expression using a PLACEHOLDER_EXPR from the
2896 FIELD_DECL node just created and link that with the
2897 corresponding GNAT defining identifier. */
2905 {
2908 }
2909 }
2911 /* Add the fields into the record type and finish it up. */
2917 /* If it is passed by reference, force BLKmode to ensure that objects
2918 of this type will always be put in memory. */
2922 /* We used to remove the associations of the discriminants and _Parent
2923 for validity checking but we may need them if there's a Freeze_Node
2924 for a subtype used in this record. */
2927 /* Fill in locations of fields. */
2930 /* If there are any entities in the chain corresponding to components
2931 that we did not elaborate, ensure we elaborate their types if they
2932 are Itypes. */
2942 /* If this is a record type associated with an exception definition,
2943 equate its fields to those of the standard exception type. This
2944 will make it possible to convert between them. */
2946 {
2947 tree gnu_std_field;
2950 gnu_field;
2955 }
2956 }
2960 /* If an equivalent type is present, that is what we should use.
2961 Otherwise, fall through to handle this like a record subtype
2962 since it may have constraints. */
2964 {
2968 }
2970 /* ... fall through ... */
2973 /* If Cloned_Subtype is Present it means this record subtype has
2974 identical layout to that type or subtype and we should use
2975 that GCC type for this one. The front end guarantees that
2976 the component list is shared. */
2978 {
2983 }
2985 /* Otherwise, first ensure the base type is elaborated. Then, if we are
2986 changing the type, make a new type with each field having the type of
2987 the field in the new subtype but the position computed by transforming
2988 every discriminant reference according to the constraints. We don't
2989 see any difference between private and non-private type here since
2990 derivations from types should have been deferred until the completion
2991 of the private type. */
2992 else
2993 {
2995 tree gnu_base_type;
2998 {
2999 defer_incomplete_level++;
3001 }
3006 {
3009 }
3011 /* If this is a record subtype associated with a dispatch table,
3012 strip the suffix. This is necessary to make sure 2 different
3013 subtypes associated with the imported and exported views of a
3014 dispatch table are properly merged in LTO mode. */
3016 {
3023 }
3025 /* When the subtype has discriminants and these discriminants affect
3026 the initial shape it has inherited, factor them in. But for an
3027 Unchecked_Union (it must be an Itype), just return the type.
3028 We can't just test Is_Constrained because private subtypes without
3029 discriminants of types with discriminants with default expressions
3030 are Is_Constrained but aren't constrained! */
3038 {
3039 tree gnu_subst_list
3044 Entity_Id gnat_field;
3049 /* Set the size, alignment and alias set of the new type to
3050 match that of the old one, doing required substitutions. */
3052 gnu_subst_list);
3056 else
3059 /* Look for a REP part in the base type. */
3062 /* Look for a variant part in the base type. */
3065 /* If there is a variant part, we must compute whether the
3066 constraints statically select a particular variant. If
3067 so, we simply drop the qualified union and flatten the
3068 list of fields. Otherwise we'll build a new qualified
3069 union for the variants that are still relevant. */
3071 {
3072 gnu_variant_list
3076 /* If all the qualifiers are unconditionally true, the
3077 innermost variant is statically selected. */
3081 {
3084 }
3086 /* Otherwise, create the new variants. */
3089 {
3095 gnu_subst_list);
3097 }
3098 }
3099 else
3100 {
3103 }
3105 gnu_pos_list
3121 {
3123 Entity_Id gnat_old_field
3125 tree gnu_old_field
3131 /* If the type is the same, retrieve the GCC type from the
3132 old field to take into account possible adjustments. */
3135 else
3138 /* If there was a component clause, the field types must be
3139 the same for the type and subtype, so copy the data from
3140 the old field to avoid recomputation here. Also if the
3141 field is justified modular and the optimization in
3142 gnat_to_gnu_field was applied. */
3148 {
3151 }
3153 /* If the old field was packed and of constant size, we
3154 have to get the old size here, as it might differ from
3155 what the Etype conveys and the latter might overlap
3156 onto the following field. Try to arrange the type for
3157 possible better packing along the way. */
3161 {
3166 gnu_field_type
3168 }
3170 else
3173 /* If the context of the old field is the base type or its
3174 REP part (if any), put the field directly in the new
3175 type; otherwise look up the context in the variant list
3176 and put the field either in the new type if there is a
3177 selected variant or in one of the new variants. */
3179 || (gnu_rep_part
3182 else
3183 {
3186 {
3189 else
3191 }
3192 else
3193 /* The front-end may pass us "ghost" components if
3194 it fails to recognize that a constrained subtype
3195 is statically constrained. Discard them. */
3197 }
3199 /* Now create the new field modeled on the old one. */
3200 gnu_field
3205 /* Put it in one of the new variants directly. */
3207 {
3210 }
3212 /* To match the layout crafted in components_to_record,
3213 if this is the _Tag or _Parent field, put it before
3214 any other fields. */
3219 /* Similarly, if this is the _Controller field, put
3220 it before the other fields except for the _Tag or
3221 _Parent field. */
3223 {
3226 }
3228 /* Otherwise, if this is a regular field, put it after
3229 the other fields. */
3230 else
3231 {
3236 }
3239 }
3241 /* If there is a variant list and no selected variant, we need
3242 to create the nest of variant parts from the old nest. */
3244 {
3245 tree new_variant_part
3251 }
3253 /* Now go through the entities again looking for Itypes that
3254 we have not elaborated but should (e.g., Etypes of fields
3255 that have Original_Components). */
3263 /* Do not emit debug info for the type yet since we're going to
3264 modify it below. */
3268 /* See the E_Record_Type case for the rationale. */
3271 else
3276 /* Fill in locations of fields. */
3279 /* If debugging information is being written for the type, write
3280 a record that shows what we are a subtype of and also make a
3281 variable that indicates our size, if still variable. */
3283 {
3295 build_reference_type
3297 gnu_subtype_marker,
3303 gnu_subtype_marker);
3313 gnat_entity);
3314 }
3316 /* Now we can finalize it. */
3318 }
3320 /* Otherwise, go down all the components in the new type and make
3321 them equivalent to those in the base type. */
3322 else
3323 {
3333 gnat_to_gnu_field_decl
3336 }
3337 }
3341 /* Use the special descriptor type for dispatch tables if needed,
3342 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3343 Note that we are only required to do so for static tables in
3344 order to be compatible with the C++ ABI, but Ada 2005 allows
3345 to extend library level tagged types at the local level so
3346 we do it in the non-static case as well. */
3349 {
3353 }
3355 /* ... fall through ... */
3358 /* If we are not defining this entity, and we have incomplete
3359 entities being processed above us, make a dummy type and
3360 fill it in later. */
3362 {
3366 gnu_type
3367 = build_pointer_type
3382 }
3384 /* ... fall through ... */
3391 {
3392 /* The designated type and its equivalent type for gigi. */
3395 /* Whether it comes from a limited with. */
3396 bool is_from_limited_with
3399 /* The "full view" of the designated type. If this is an incomplete
3400 entity from a limited with, treat its non-limited view as the full
3401 view. Otherwise, if this is an incomplete or private type, use the
3402 full view. In the former case, we might point to a private type,
3403 in which case, we need its full view. Also, we want to look at the
3404 actual type used for the representation, so this takes a total of
3405 three steps. */
3406 Entity_Id gnat_desig_full_direct_first
3407 = (is_from_limited_with
3411 Entity_Id gnat_desig_full_direct
3412 = ((is_from_limited_with
3417 Entity_Id gnat_desig_full
3419 /* The type actually used to represent the designated type, either
3420 gnat_desig_full or gnat_desig_equiv. */
3421 Entity_Id gnat_desig_rep;
3422 /* True if this is a pointer to an unconstrained array. */
3424 /* We want to know if we'll be seeing the freeze node for any
3425 incomplete type we may be pointing to. */
3426 bool in_main_unit
3430 /* True if we make a dummy type here. */
3432 /* True if the dummy type is a fat pointer. */
3434 /* The mode to be used for the pointer type. */
3436 /* The GCC type used for the designated type. */
3442 /* If either the designated type or its full view is an unconstrained
3443 array subtype, replace it with the type it's a subtype of. This
3444 avoids problems with multiple copies of unconstrained array types.
3445 Likewise, if the designated type is a subtype of an incomplete
3446 record type, use the parent type to avoid order of elaboration
3447 issues. This can lose some code efficiency, but there is no
3448 alternative. */
3459 /* Set the type that's actually the representation of the designated
3460 type and also flag whether we have a unconstrained array. */
3461 gnat_desig_rep
3463 is_unconstrained_array
3466 /* If we are pointing to an incomplete type whose completion is an
3467 unconstrained array, make a fat pointer type. The two types in our
3468 fields will be pointers to dummy nodes and will be replaced in
3469 update_pointer_to. Similarly, if the type itself is a dummy type or
3470 an unconstrained array. Also make a dummy TYPE_OBJECT_RECORD_TYPE
3471 in case we have any thin pointers to it. */
3475 && TYPE_IS_DUMMY_P
3477 || (!in_main_unit
3478 && defer_incomplete_level
3480 || (in_main_unit
3481 && is_from_limited_with
3483 {
3486 else
3487 {
3489 /* Show the dummy we get will be a fat pointer. */
3491 }
3493 /* If the call above got something that has a pointer, the pointer
3494 is our type. This could have happened either because the type
3495 was elaborated or because somebody else executed the code. */
3498 {
3503 tree fields;
3517 fields
3526 /* Make sure we can place this into a register. */
3531 /* Do not emit debug info for this record type since the types
3532 of its fields are incomplete. */
3540 }
3541 }
3543 /* If we already know what the full type is, use it. */
3548 /* Get the type of the thing we are to point to and build a pointer to
3549 it. If it is a reference to an incomplete or private type with a
3550 full view that is a record, make a dummy type node and get the
3551 actual type later when we have verified it is safe. */
3557 /* Likewise if we are pointing to a record or array and we are
3558 to defer elaborating incomplete types. We do this as this
3559 access type may be the full view of a private type. Note
3560 that the unconstrained array case is handled above. */
3562 && defer_incomplete_level
3566 /* If this is a reference from a limited_with type back to our
3567 main unit and there's a freeze node for it, either we have
3568 already processed the declaration and made the dummy type,
3569 in which case we just reuse the latter, or we have not yet,
3570 in which case we make the dummy type and it will be reused
3571 when the declaration is finally processed. In both cases,
3572 the pointer eventually created below will be automatically
3573 adjusted when the freeze node is processed. Note that the
3574 unconstrained array case is handled above. */
3575 || (in_main_unit
3576 && is_from_limited_with
3578 {
3581 }
3583 /* Otherwise handle the case of a pointer to itself. */
3585 {
3586 gnu_type
3590 }
3592 /* If expansion is disabled, the equivalent type of a concurrent type
3593 is absent, so build a dummy pointer type. */
3597 /* Finally, handle the default case where we can just elaborate our
3598 designated type. */
3599 else
3602 /* It is possible that a call to gnat_to_gnu_type above resolved our
3603 type. If so, just return it. */
3605 {
3608 }
3610 /* If we have not done it yet, build the pointer type the usual way. */
3612 {
3613 /* Modify the designated type if we are pointing only to constant
3614 objects, but don't do it for unconstrained arrays. */
3617 {
3618 gnu_desig_type
3619 = build_qualified_type
3623 /* Some extra processing is required if we are building a
3624 pointer to an incomplete type (in the GCC sense). We might
3625 have such a type if we just made a dummy, or directly out
3626 of the call to gnat_to_gnu_type above if we are processing
3627 an access type for a record component designating the
3628 record type itself. */
3630 {
3631 /* We must ensure that the pointer to variant we make will
3632 be processed by update_pointer_to when the initial type
3633 is completed. Pretend we made a dummy and let further
3634 processing act as usual. */
3637 /* We must ensure that update_pointer_to will not retrieve
3638 the dummy variant when building a properly qualified
3639 version of the complete type. We take advantage of the
3640 fact that get_qualified_type is requiring TYPE_NAMEs to
3641 match to influence build_qualified_type and then also
3642 update_pointer_to here. */
3645 }
3646 }
3648 gnu_type
3651 }
3653 /* If we are not defining this object and we have made a dummy pointer,
3654 save our current definition, evaluate the actual type, and replace
3655 the tentative type we made with the actual one. If we are to defer
3656 actually looking up the actual type, make an entry in the deferred
3657 list. If this is from a limited with, we have to defer to the end
3658 of the current spec in two cases: first if the designated type is
3659 in the current unit and second if the access type itself is. */
3661 {
3662 bool is_from_limited_with_in_main_unit
3663 = (is_from_limited_with
3664 && (in_main_unit
3666 tree gnu_old_desig_type
3672 gnu_type
3673 = build_pointer_type
3674 (TYPE_OBJECT_RECORD_TYPE
3685 /* Note that the call to gnat_to_gnu_type on gnat_desig_equiv might
3686 update gnu_old_desig_type directly, in which case it will not be
3687 a dummy type any more when we get into update_pointer_to.
3689 This can happen e.g. when the designated type is a record type,
3690 because their elaboration starts with an initial node from
3691 make_dummy_type, which may be the same node as the one we got.
3693 Besides, variants of this non-dummy type might have been created
3694 along the way. update_pointer_to is expected to properly take
3695 care of those situations. */
3699 else
3700 {
3703 = (is_from_limited_with_in_main_unit
3709 }
3710 }
3711 }
3718 else
3719 {
3720 /* The run-time representation is the equivalent type. */
3723 }
3736 /* We treat this as identical to its base type; any constraint is
3737 meaningful only to the front end.
3739 The designated type must be elaborated as well, if it does
3740 not have its own freeze node. Designated (sub)types created
3741 for constrained components of records with discriminants are
3742 not frozen by the front end and thus not elaborated by gigi,
3743 because their use may appear before the base type is frozen,
3744 and because it is not clear that they are needed anywhere in
3745 Gigi. With the current model, there is no correct place where
3746 they could be elaborated. */
3753 {
3754 /* If we are not defining this entity, and we have incomplete
3755 entities being processed above us, make a dummy type and
3756 elaborate it later. */
3758 {
3761 tree gnu_ptr_type
3762 = build_pointer_type
3769 }
3772 Incomplete_Or_Private_Kind))
3775 }
3780 /* Subprogram Entities
3782 The following access functions are defined for subprograms (functions
3783 or procedures):
3785 First_Formal The first formal parameter.
3786 Is_Imported Indicates that the subprogram has appeared in
3787 an INTERFACE or IMPORT pragma. For now we
3788 assume that the external language is C.
3789 Is_Exported Likewise but for an EXPORT pragma.
3790 Is_Inlined True if the subprogram is to be inlined.
3792 In addition for function subprograms we have:
3794 Etype Return type of the function.
3796 Each parameter is first checked by calling must_pass_by_ref on its
3797 type to determine if it is passed by reference. For parameters which
3798 are copied in, if they are Ada In Out or Out parameters, their return
3799 value becomes part of a record which becomes the return type of the
3800 function (C function - note that this applies only to Ada procedures
3801 so there is no Ada return type). Additional code to store back the
3802 parameters will be generated on the caller side. This transformation
3803 is done here, not in the front-end.
3805 The intended result of the transformation can be seen from the
3806 equivalent source rewritings that follow:
3808 struct temp {int a,b};
3809 procedure P (A,B: In Out ...) is temp P (int A,B)
3810 begin {
3811 .. ..
3812 end P; return {A,B};
3813 }
3815 temp t;
3816 P(X,Y); t = P(X,Y);
3817 X = t.a , Y = t.b;
3819 For subprogram types we need to perform mainly the same conversions to
3820 GCC form that are needed for procedures and function declarations. The
3821 only difference is that at the end, we make a type declaration instead
3822 of a function declaration. */
3827 {
3828 /* The first GCC parameter declaration (a PARM_DECL node). The
3829 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3830 actually is the head of this parameter list. */
3832 /* Likewise for the stub associated with an exported procedure. */
3834 /* The type returned by a function. If the subprogram is a procedure
3835 this type should be void_type_node. */
3837 /* List of fields in return type of procedure with copy-in copy-out
3838 parameters. */
3840 /* Non-null for subprograms containing parameters passed by copy-in
3841 copy-out (Ada In Out or Out parameters not passed by reference),
3842 in which case it is the list of nodes used to specify the values
3843 of the In Out/Out parameters that are returned as a record upon
3844 procedure return. The TREE_PURPOSE of an element of this list is
3845 a field of the record and the TREE_VALUE is the PARM_DECL
3846 corresponding to that field. This list will be saved in the
3847 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3849 /* If an import pragma asks to map this subprogram to a GCC builtin,
3850 this is the builtin DECL node. */
3852 /* For the stub associated with an exported procedure. */
3855 Entity_Id gnat_param;
3858 bool extern_flag
3861 /* The semantics of "pure" in Ada essentially matches that of "const"
3862 in the back-end. In particular, both properties are orthogonal to
3863 the "nothrow" property if the EH circuitry is explicit in the
3864 internal representation of the back-end. If we are to completely
3865 hide the EH circuitry from it, we need to declare that calls to pure
3866 Ada subprograms that can throw have side effects since they can
3867 trigger an "abnormal" transfer of control flow; thus they can be
3868 neither "const" nor "pure" in the back-end sense. */
3869 bool const_flag
3881 /* A parameter may refer to this type, so defer completion of any
3882 incomplete types. */
3884 {
3885 defer_incomplete_level++;
3887 }
3889 /* If the subprogram has an alias, it is probably inherited, so
3890 we can use the original one. If the original "subprogram"
3891 is actually an enumeration literal, it may be the first use
3892 of its type, so we must elaborate that type now. */
3894 {
3901 /* Elaborate any Itypes in the parameters of this entity. */
3909 }
3911 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3912 corresponding DECL node. Proper generation of calls later on need
3913 proper parameter associations so we don't "break;" here. */
3916 {
3919 /* Unability to find the builtin decl most often indicates a
3920 genuine mistake, but imports of unregistered intrinsics are
3921 sometimes issued on purpose to allow hooking in alternate
3922 bodies. We post a warning conditioned on Wshadow in this case,
3923 to let developers be notified on demand without risking false
3924 positives with common default sets of options. */
3928 }
3930 /* ??? What if we don't find the builtin node above ? warn ? err ?
3931 In the current state we neither warn nor err, and calls will just
3932 be handled as for regular subprograms. */
3937 /* If this function returns by reference, make the actual return
3938 type of this function the pointer and mark the decl. */
3940 {
3943 }
3945 /* If the Mechanism is By_Reference, ensure this function uses the
3946 target's by-invisible-reference mechanism, which may not be the
3947 same as above (e.g. it might be passing an extra parameter).
3949 Prior to GCC 4, this was handled by just setting TREE_ADDRESSABLE
3950 on the result type. Everything required to pass by invisible
3951 reference using the target's mechanism (e.g. an extra parameter)
3952 was handled at RTL expansion time.
3954 This doesn't work with GCC 4 any more for several reasons. First,
3955 the gimplification process might need to create temporaries of this
3956 type and the gimplifier ICEs on such attempts; that's why the flag
3957 is now set on the function type instead. Second, the middle-end
3958 now also relies on a different attribute, DECL_BY_REFERENCE on the
3959 RESULT_DECL, and expects the by-invisible-reference-ness to be made
3960 explicit in the function body. */
3964 /* If we are supposed to return an unconstrained array, actually return
3965 a fat pointer and make a note of that. */
3967 {
3970 }
3972 /* If the type requires a transient scope, the result is allocated
3973 on the secondary stack, so the result type of the function is
3974 just a pointer. */
3976 {
3979 }
3981 /* If the type is a padded type and the underlying type would not
3982 be passed by reference or this function has a foreign convention,
3983 return the underlying type. */
3990 /* If the return type is unconstrained, that means it must have a
3991 maximum size. Use the padded type as the effective return type.
3992 And ensure the function uses the target's by-invisible-reference
3993 mechanism to avoid copying too much data when it returns. */
3995 {
3996 gnu_return_type
4001 }
4003 /* If the return type has a size that overflows, we cannot have
4004 a function that returns that type. This usage doesn't make
4005 sense anyway, so give an error here. */
4009 {
4011 gnat_entity);
4017 }
4019 /* Look at all our parameters and get the type of
4020 each. While doing this, build a copy-out structure if
4021 we need one. */
4023 /* Loop over the parameters and get their associated GCC tree.
4024 While doing this, build a copy-out structure if we need one. */
4028 {
4035 /* Builtins are expanded inline and there is no real call sequence
4036 involved. So the type expected by the underlying expander is
4037 always the type of each argument "as is". */
4040 /* Handle the first parameter of a valued procedure specially. */
4043 /* Otherwise, see if a Mechanism was supplied that forced this
4044 parameter to be passed one way or another. */
4047 ;
4056 {
4060 mech))
4062 else
4064 }
4065 else
4066 {
4069 }
4071 gnu_param
4076 /* We are returned either a PARM_DECL or a type if no parameter
4077 needs to be passed; in either case, adjust the type. */
4080 else
4081 {
4084 }
4087 {
4088 /* If it's an exported subprogram, we build a parameter list
4089 in parallel, in case we need to emit a stub for it. */
4091 {
4092 gnu_stub_param_list
4094 /* Change By_Descriptor parameter to By_Reference for
4095 the internal version of an exported subprogram. */
4097 {
4098 gnu_param
4103 }
4104 else
4106 }
4113 /* If a parameter is a pointer, this function may modify
4114 memory through it and thus shouldn't be considered
4115 a const function. Also, the memory may be modified
4116 between two calls, so they can't be CSE'ed. The latter
4117 case also handles by-ref parameters. */
4121 }
4124 {
4126 {
4130 /* Set a default alignment to speed up accesses. */
4134 }
4136 gnu_field
4144 gnu_cico_list
4146 }
4147 }
4149 /* Do not compute record for out parameters if subprogram is
4150 stubbed since structures are incomplete for the back-end. */
4155 /* If we have a CICO list but it has only one entry, we convert
4156 this function into a function that simply returns that one
4157 object. */
4162 prepend_one_attribute_to
4165 gnat_entity);
4167 /* If we are on a target where stack realignment is needed for 'main'
4168 to honor GCC's implicit expectations (stack alignment greater than
4169 what the base ABI guarantees), ensure we do the same for foreign
4170 convention subprograms as they might be used as callbacks from code
4171 breaking such expectations. Note that this applies to task entry
4172 points in particular. */
4175 prepend_one_attribute_to
4178 gnat_entity);
4180 /* The lists have been built in reverse. */
4188 || return_by_direct_ref_p
4189 || return_by_invisi_ref_p
4191 gnu_type
4194 return_by_direct_ref_p,
4195 return_by_invisi_ref_p);
4198 gnu_stub_type
4201 return_by_direct_ref_p,
4202 return_by_invisi_ref_p);
4204 /* A subprogram (something that doesn't return anything) shouldn't
4205 be considered const since there would be no reason for such a
4206 subprogram. Note that procedures with Out (or In Out) parameters
4207 have already been converted into a function with a return type. */
4211 gnu_type
4218 gnu_stub_type
4224 /* If we have a builtin decl for that function, use it. Check if the
4225 profiles are compatible and warn if they are not. The checker is
4226 expected to post extra diagnostics in this case. */
4228 {
4229 intrin_binding_t inb;
4236 post_error
4238 gnat_entity);
4243 }
4245 /* If there was no specified Interface_Name and the external and
4246 internal names of the subprogram are the same, only use the
4247 internal name to allow disambiguation of nested subprograms. */
4252 /* If we are defining the subprogram and it has an Address clause
4253 we must get the address expression from the saved GCC tree for the
4254 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4255 the address expression here since the front-end has guaranteed
4256 in that case that the elaboration has no effects. If there is
4257 an Address clause and we are not defining the object, just
4258 make it a constant. */
4260 {
4264 gnu_address
4271 /* Convert the type of the object to a reference type that can
4272 alias everything as per 13.3(19). */
4273 gnu_type
4278 gnu_decl
4283 }
4289 else
4290 {
4292 {
4296 }
4302 gnat_entity);
4304 {
4305 tree gnu_stub_decl
4310 gnat_entity);
4312 }
4314 /* This is unrelated to the stub built right above. */
4317 }
4318 }
4329 {
4330 /* Get the "full view" of this entity. If this is an incomplete
4331 entity from a limited with, treat its non-limited view as the
4332 full view. Otherwise, use either the full view or the underlying
4333 full view, whichever is present. This is used in all the tests
4334 below. */
4335 Entity_Id full_view
4343 /* If this is an incomplete type with no full view, it must be a Taft
4344 Amendment type, in which case we return a dummy type. Otherwise,
4345 just get the type from its Etype. */
4347 {
4349 {
4352 }
4353 else
4354 {
4358 }
4360 }
4362 /* If we already made a type for the full view, reuse it. */
4364 {
4367 }
4369 /* Otherwise, if we are not defining the type now, get the type
4370 from the full view. But always get the type from the full view
4371 for define on use types, since otherwise we won't see them! */
4377 {
4381 }
4383 /* For incomplete types, make a dummy type entry which will be
4384 replaced later. Save it as the full declaration's type so
4385 we can do any needed updates when we see it. */
4390 }
4393 /* Class-wide types are always transformed into their root type. */
4402 /* Concurrent types are always transformed into their record type. */
4405 else
4416 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4417 we've already saved it, so we don't try to. */
4424 }
4426 /* If we had a case where we evaluated another type and it might have
4427 defined this one, handle it here. */
4429 {
4432 }
4434 /* If we are processing a type and there is either no decl for it or
4435 we just made one, do some common processing for the type, such as
4436 handling alignment and possible padding. */
4438 {
4439 /* Tell the middle-end that objects of tagged types are guaranteed to
4440 be properly aligned. This is necessary because conversions to the
4441 class-wide type are translated into conversions to the root type,
4442 which can be less aligned than some of its derived types. */
4447 /* If the type is passed by reference, objects of this type must be
4448 fully addressable and cannot be copied. */
4452 /* ??? Don't set the size for a String_Literal since it is either
4453 confirming or we don't handle it properly (if the low bound is
4454 non-constant). */
4460 /* If a size was specified, see if we can make a new type of that size
4461 by rearranging the type, for example from a fat to a thin pointer. */
4463 {
4464 gnu_type
4471 }
4473 /* If the alignment hasn't already been processed and this is
4474 not an unconstrained array, see if an alignment is specified.
4475 If not, we pick a default alignment for atomic objects. */
4477 ;
4479 {
4483 /* Warn on suspiciously large alignments. This should catch
4484 errors about the (alignment,byte)/(size,bit) discrepancy. */
4486 {
4487 tree size;
4489 /* If a size was specified, take it into account. Otherwise
4490 use the RM size for records as the type size has already
4491 been adjusted to the alignment. */
4499 else
4502 /* Consider an alignment as suspicious if the alignment/size
4503 ratio is greater or equal to the byte/bit ratio. */
4508 gnat_entity);
4509 }
4510 }
4521 /* See if we need to pad the type. If we did, and made a record,
4522 the name of the new type may be changed. So get it back for
4523 us when we make the new TYPE_DECL below. */
4529 {
4533 }
4537 /* If we are at global level, GCC will have applied variable_size to
4538 the type, but that won't have done anything. So, if it's not
4539 a constant or self-referential, call elaborate_expression_1 to
4540 make a variable for the size rather than calculating it each time.
4541 Handle both the RM size and the actual size. */
4546 {
4554 /* ??? For now, store the size as a multiple of the alignment in
4555 bytes so that we can see the alignment from the tree. */
4562 /* ??? gnu_type may come from an existing type so the MULT_EXPR node
4563 may not be marked by the call to create_type_decl below. */
4567 {
4572 {
4576 /* If the position of the variant part is constant, subtract
4577 it from the size of the type of the parent to get the new
4578 size. This manual CSE reduces the data size. */
4580 {
4588 }
4589 else
4590 {
4593 gnat_entity,
4597 /* ??? For now, store the size as a multiple of the
4598 alignment in bytes so that we can see the alignment
4599 from the tree. */
4602 gnat_entity,
4603 get_identifier
4608 /* ??? For now, store the offset as a multiple of the
4609 alignment in bytes so that we can see the alignment
4610 from the tree. */
4613 gnat_entity,
4616 DECL_OFFSET_ALIGN
4618 }
4622 }
4626 else
4627 ada_size
4632 }
4633 }
4635 /* If this is a record type or subtype, call elaborate_expression_1 on
4636 any field position. Do this for both global and local types.
4637 Skip any fields that we haven't made trees for to avoid problems with
4638 class wide types. */
4643 {
4646 /* ??? For now, store the offset as a multiple of the alignment
4647 in bytes so that we can see the alignment from the tree. */
4649 {
4652 gnat_temp,
4657 /* ??? The context of gnu_field is not necessarily gnu_type
4658 so the MULT_EXPR node built above may not be marked by
4659 the call to create_type_decl below. */
4662 }
4663 }
4666 gnu_type
4683 else
4684 {
4687 }
4688 }
4691 {
4694 /* If this is a derived type, relate its alias set to that of its parent
4695 to avoid troubles when a call to an inherited primitive is inlined in
4696 a context where a derived object is accessed. The inlined code works
4697 on the parent view so the resulting code may access the same object
4698 using both the parent and the derived alias sets, which thus have to
4699 conflict. As the same issue arises with component references, the
4700 parent alias set also has to conflict with composite types enclosing
4701 derived components. For instance, if we have:
4703 type D is new T;
4704 type R is record
4705 Component : D;
4706 end record;
4708 we want T to conflict with both D and R, in addition to R being a
4709 superset of D by record/component construction.
4711 One way to achieve this is to perform an alias set copy from the
4712 parent to the derived type. This is not quite appropriate, though,
4713 as we don't want separate derived types to conflict with each other:
4715 type I1 is new Integer;
4716 type I2 is new Integer;
4718 We want I1 and I2 to both conflict with Integer but we do not want
4719 I1 to conflict with I2, and an alias set copy on derivation would
4720 have that effect.
4722 The option chosen is to make the alias set of the derived type a
4723 superset of that of its parent type. It trivially fulfills the
4724 simple requirement for the Integer derivation example above, and
4725 the component case as well by superset transitivity:
4727 superset superset
4728 R ----------> D ----------> T
4730 However, for composite types, conversions between derived types are
4731 translated into VIEW_CONVERT_EXPRs so a sequence like:
4733 type Comp1 is new Comp;
4734 type Comp2 is new Comp;
4735 procedure Proc (C : Comp1);
4737 C : Comp2;
4738 Proc (Comp1 (C));
4740 is translated into:
4742 C : Comp2;
4743 Proc ((Comp1 &) &VIEW_CONVERT_EXPR <Comp1> (C));
4745 and gimplified into:
4747 C : Comp2;
4748 Comp1 *C.0;
4749 C.0 = (Comp1 *) &C;
4750 Proc (C.0);
4752 i.e. generates code involving type punning. Therefore, Comp1 needs
4753 to conflict with Comp2 and an alias set copy is required.
4755 The language rules ensure the parent type is already frozen here. */
4757 {
4762 }
4764 /* Back-annotate the Alignment of the type if not already in the
4765 tree. Likewise for sizes. */
4767 {
4771 /* If the default alignment of "double" or larger scalar types is
4772 specifically capped and this is not an array with an alignment
4773 clause on the component type, return the cap. */
4775 is_capped_double
4778 is_capped_double
4780 else
4785 else
4789 }
4792 {
4795 /* If the size is self-referential, annotate the maximum value. */
4800 {
4801 /* In this mode, the tag and the parent components are not
4802 generated by the front-end so the sizes must be adjusted. */
4804 Uint uint_size;
4807 {
4809 bitsizetype);
4812 }
4813 else
4819 gnu_size,
4820 pointer_size));
4824 }
4825 else
4827 }
4831 }
4841 /* If we haven't already, associate the ..._DECL node that we just made with
4842 the input GNAT entity node. */
4846 /* If this is an enumeration or floating-point type, we were not able to set
4847 the bounds since they refer to the type. These are always static. */
4850 {
4854 /* If this is a padded type, we need to use the underlying type. */
4858 /* If this is a floating point type and we haven't set a floating
4859 point type yet, use this in the evaluation of the bounds. */
4867 {
4868 /* Enumeration types have specific RM bounds. */
4872 /* Write full debugging information. Since this has both a
4873 typedef and a tag, avoid outputting the name twice. */
4876 }
4878 else
4879 {
4880 /* Floating-point types don't have specific RM bounds. */
4883 }
4884 }
4886 /* If we deferred processing of incomplete types, re-enable it. If there
4887 were no other disables and we have some to process, do so. */
4889 {
4891 {
4894 /* We are back to level 0 for the deferring of incomplete types.
4895 But processing these incomplete types below may itself require
4896 deferring, so preserve what we have and restart from scratch. */
4900 /* For finalization, however, all types must be complete so we
4901 cannot do the same because deferred incomplete types may end up
4902 referencing each other. Process them all recursively first. */
4903 defer_finalize_level++;
4906 {
4913 }
4915 defer_finalize_level--;
4916 }
4918 /* All the deferred incomplete types have been processed so we can
4919 now proceed with the finalization of the deferred types. */
4921 {
4923 tree t;
4929 }
4930 }
4932 /* If we are not defining this type, see if it's in the incomplete list.
4933 If so, handle that list entry now. */
4935 {
4940 {
4944 }
4945 }
4948 force_global--;
4950 /* If this is a packed array type whose original array type is itself
4951 an Itype without freeze node, make sure the latter is processed. */
4959 }
4961 /* Similar, but if the returned value is a COMPONENT_REF, return the
4962 FIELD_DECL. */
4964 tree
4966 {
4973 }
4975 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
4976 the GCC type corresponding to that entity. */
4978 tree
4980 {
4981 tree gnu_decl;
4983 /* The back end never attempts to annotate generic types. */
4991 }
4993 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
4994 the unpadded version of the GCC type corresponding to that entity. */
4996 tree
4998 {
5005 }
5006 \f
5007 /* Wrap up compilation of DECL, a TYPE_DECL, possibly deferring it.
5008 Every TYPE_DECL generated for a type definition must be passed
5009 to this function once everything else has been done for it. */
5011 void
5013 {
5014 /* We need to defer finalizing the type if incomplete types
5015 are being deferred or if they are being processed. */
5018 else
5020 }
5022 /* Same as above but without deferring the compilation. This
5023 function should not be invoked directly on a TYPE_DECL. */
5025 static void
5027 {
5033 /* Now process all the variants. This is needed for STABS. */
5035 {
5043 }
5044 }
5046 /* Finalize any From_With_Type incomplete types. We do this after processing
5047 our compilation unit and after processing its spec, if this is a body. */
5049 void
5051 {
5057 {
5064 }
5065 }
5067 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
5068 kind of type (such E_Task_Type) that has a different type which Gigi
5069 uses for its representation. If the type does not have a special type
5070 for its representation, return GNAT_ENTITY. If a type is supposed to
5071 exist, but does not, abort unless annotating types, in which case
5072 return Empty. If GNAT_ENTITY is Empty, return Empty. */
5074 Entity_Id
5076 {
5083 {
5107 }
5111 }
5113 /* Return a GCC tree for a type corresponding to the component type of the
5114 array type or subtype GNAT_ARRAY. DEFINITION is true if this component
5115 is for an array being defined. DEBUG_INFO_P is true if we need to write
5116 debug information for other types that we may create in the process. */
5118 static tree
5121 {
5123 tree gnu_comp_size;
5125 /* Try to get a smaller form of the component if needed. */
5139 /* Get and validate any specified Component_Size. */
5140 gnu_comp_size
5145 /* If the array has aliased components and the component size can be zero,
5146 force at least unit size to ensure that the components have distinct
5147 addresses. */
5153 gnu_comp_size
5156 /* If the component type is a RECORD_TYPE that has a self-referential size,
5157 then use the maximum size for the component size. */
5163 /* Honor the component size. This is not needed for bit-packed arrays. */
5165 {
5169 /* If an alignment is specified, use it as a cap on the component type
5170 so that it can be honored for the whole type. But ignore it for the
5171 original type of packed array types. */
5174 else
5180 else
5186 /* If a padding record was made, declare it now since it will never be
5187 declared otherwise. This is necessary to ensure that its subtrees
5188 are properly marked. */
5192 }
5195 gnu_type
5200 }
5202 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
5203 using MECH as its passing mechanism, to be placed in the parameter
5204 list built for GNAT_SUBPROG. Assume a foreign convention for the
5205 latter if FOREIGN is true. Also set CICO to true if the parameter
5206 must use the copy-in copy-out implementation mechanism.
5208 The returned tree is a PARM_DECL, except for those cases where no
5209 parameter needs to be actually passed to the subprogram; the type
5210 of this "shadow" parameter is then returned instead. */
5212 static tree
5215 {
5220 /* The parameter can be indirectly modified if its address is taken. */
5223 tree gnu_param;
5225 /* Copy-return is used only for the first parameter of a valued procedure.
5226 It's a copy mechanism for which a parameter is never allocated. */
5228 {
5232 }
5234 /* If this is either a foreign function or if the underlying type won't
5235 be passed by reference, strip off possible padding type. */
5237 {
5241 || foreign
5245 }
5247 /* If this is a read-only parameter, make a variant of the type that is
5248 read-only. ??? However, if this is an unconstrained array, that type
5249 can be very complex, so skip it for now. Likewise for any other
5250 self-referential type. */
5258 /* For foreign conventions, pass arrays as pointers to the element type.
5259 First check for unconstrained array and get the underlying array. */
5261 gnu_param_type
5264 /* For GCC builtins, pass Address integer types as (void *) */
5270 /* VMS descriptors are themselves passed by reference. */
5273 gnu_param_type
5276 gnat_subprog));
5278 {
5279 /* Build both a 32-bit and 64-bit descriptor, one of which will be
5280 chosen in fill_vms_descriptor. */
5281 gnu_param_type_alt
5284 gnat_subprog));
5285 gnu_param_type
5288 gnat_subprog));
5289 }
5291 /* Arrays are passed as pointers to element type for foreign conventions. */
5295 {
5296 /* Strip off any multi-dimensional entries, then strip
5297 off the last array to get the component type. */
5311 }
5313 /* Fat pointers are passed as thin pointers for foreign conventions. */
5315 gnu_param_type
5318 /* If we must pass or were requested to pass by reference, do so.
5319 If we were requested to pass by copy, do so.
5320 Otherwise, for foreign conventions, pass In Out or Out parameters
5321 or aggregates by reference. For COBOL and Fortran, pass all
5322 integer and FP types that way too. For Convention Ada, use
5323 the standard Ada default. */
5327 && ((foreign
5329 || (foreign
5334 || (!foreign
5336 {
5339 }
5341 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
5348 /* If this is an Out parameter that isn't passed by reference and isn't
5349 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
5350 it will be a VAR_DECL created when we process the procedure, so just
5351 return its type. For the special parameter of a valued procedure,
5352 never pass it in.
5354 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
5355 Out parameters with discriminants or implicit initial values to be
5356 handled like In Out parameters. These type are normally built as
5357 aggregates, hence passed by reference, except for some packed arrays
5358 which end up encoded in special integer types.
5360 The exception we need to make is then for packed arrays of records
5361 with discriminants or implicit initial values. We have no light/easy
5362 way to check for the latter case, so we merely check for packed arrays
5363 of records. This may lead to useless copy-in operations, but in very
5364 rare cases only, as these would be exceptions in a set of already
5365 exceptional situations. */
5367 && !by_ref
5368 && (by_return
5387 /* Save the alternate descriptor type, if any. */
5391 /* If no Mechanism was specified, indicate what we're using, then
5392 back-annotate it. */
5398 }
5400 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
5402 static bool
5404 {
5411 return
5413 }
5415 /* Return true if the array type GNU_TYPE, which represents a dimension of
5416 GNAT_TYPE, has a non-aliased component in the back-end sense. */
5418 static bool
5420 {
5421 /* If the array type is not the innermost dimension of the GNAT type,
5422 then it has a non-aliased component. */
5427 /* If the array type has an aliased component in the front-end sense,
5428 then it also has an aliased component in the back-end sense. */
5432 /* If this is a derived type, then it has a non-aliased component if
5433 and only if its parent type also has one. */
5435 {
5439 gnu_parent_type
5444 }
5446 /* Otherwise, rely exclusively on properties of the element type. */
5448 }
5450 /* Return true if GNAT_ADDRESS is a value known at compile-time. */
5452 static bool
5454 {
5455 /* Catch System'To_Address. */
5460 }
5462 /* Return true if GNAT_RANGE, a N_Range node, cannot be superflat, i.e. if the
5463 inequality HB >= LB-1 is true. LB and HB are the low and high bounds. */
5465 static bool
5467 {
5469 Node_Id scalar_range;
5472 /* If the low bound is not constant, try to find an upper bound. */
5481 /* If the high bound is not constant, try to find a lower bound. */
5490 /* If we have failed to find constant bounds, punt. */
5495 /* We need at least a signed 64-bit type to catch most cases. */
5501 /* If the low bound is the smallest integer, nothing can be smaller. */
5507 }
5509 /* Return true if GNU_EXPR is (essentially) the address of a CONSTRUCTOR. */
5511 static bool
5513 {
5521 }
5522 \f
5523 /* Given GNAT_ENTITY, elaborate all expressions that are required to
5524 be elaborated at the point of its definition, but do nothing else. */
5526 void
5528 {
5530 {
5537 {
5541 /* ??? Tests to avoid Constraint_Error in static expressions
5542 are needed until after the front stops generating bogus
5543 conversions on bounds of real types. */
5551 }
5554 {
5558 /* If this is a record extension, go a level further to find the
5559 record definition. */
5562 }
5572 {
5573 Node_Id gnat_discriminant_expr;
5574 Entity_Id gnat_field;
5578 gnat_discriminant_expr
5583 /* ??? For now, ignore access discriminants. */
5588 }
5591 }
5592 }
5593 \f
5594 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
5595 any entities on its entity chain similarly. */
5597 void
5599 {
5600 Entity_Id gnat_sub_entity;
5603 /* If this has an entity list, process all in the list. */
5620 /* Now clear this if it has been defined, but only do so if it isn't
5621 a subprogram or parameter. We could refine this, but it isn't
5622 worth it. If this is statically allocated, it is supposed to
5623 hang around out of cope. */
5626 {
5629 }
5630 }
5631 \f
5632 /* Relate the alias sets of GNU_NEW_TYPE and GNU_OLD_TYPE according to OP.
5633 If this is a multi-dimensional array type, do this recursively.
5635 OP may be
5636 - ALIAS_SET_COPY: the new set is made a copy of the old one.
5637 - ALIAS_SET_SUPERSET: the new set is made a superset of the old one.
5638 - ALIAS_SET_SUBSET: the new set is made a subset of the old one. */
5640 static void
5642 {
5643 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
5644 of a one-dimensional array, since the padding has the same alias set
5645 as the field type, but if it's a multi-dimensional array, we need to
5646 see the inner types. */
5652 /* Unconstrained array types are deemed incomplete and would thus be given
5653 alias set 0. Retrieve the underlying array type. */
5655 gnu_old_type
5658 gnu_new_type
5667 {
5669 /* The alias set shouldn't be copied between array types with different
5670 aliasing settings because this can break the aliasing relationship
5671 between the array type and its element type. */
5672 #ifndef ENABLE_CHECKING
5674 #endif
5685 {
5689 /* Do nothing if the alias sets conflict. This ensures that we
5690 never call record_alias_subset several times for the same pair
5691 or at all for alias set 0. */
5693 {
5696 else
5698 }
5699 }
5704 }
5707 }
5708 \f
5709 /* Return true if the size represented by GNU_SIZE can be handled by an
5710 allocation. If STATIC_P is true, consider only what can be done with a
5711 static allocation. */
5713 static bool
5715 {
5716 HOST_WIDE_INT our_size;
5718 /* If this is not a static allocation, the only case we want to forbid
5719 is an overflowing size. That will be converted into a raise a
5720 Storage_Error. */
5725 /* Otherwise, we need to deal with both variable sizes and constant
5726 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
5727 since assemblers may not like very large sizes. */
5733 }
5734 \f
5735 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
5736 NAME, ARGS and ERROR_POINT. */
5738 static void
5741 tree attr_name,
5742 tree attr_args,
5743 Node_Id attr_error_point)
5744 {
5754 }
5756 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
5758 static void
5760 {
5761 Node_Id gnat_temp;
5763 /* Attributes are stored as Representation Item pragmas. */
5768 {
5773 /* Map the kind of pragma at hand. Skip if this is not one
5774 we know how to handle. */
5777 {
5808 }
5810 /* See what arguments we have and turn them into GCC trees for
5811 attribute handlers. These expect identifier for strings. We
5812 handle at most two arguments, static expressions only. */
5815 {
5821 {
5828 }
5832 {
5837 }
5838 }
5840 /* Prepend to the list now. Make a list of the argument we might
5841 have, as GCC expects it. */
5842 prepend_one_attribute_to
5849 }
5850 }
5851 \f
5852 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
5853 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
5854 return the GCC tree to use for that expression. GNU_NAME is the suffix
5855 to use if a variable needs to be created and DEFINITION is true if this
5856 is a definition of GNAT_ENTITY. If NEED_VALUE is true, we need a result;
5857 otherwise, we are just elaborating the expression for side-effects. If
5858 NEED_DEBUG is true, we need a variable for debugging purposes even if it
5859 isn't needed for code generation. */
5861 static tree
5864 {
5865 tree gnu_expr;
5867 /* If we already elaborated this expression (e.g. it was involved
5868 in the definition of a private type), use the old value. */
5872 /* If we don't need a value and this is static or a discriminant,
5873 we don't need to do anything. */
5880 /* If it's a static expression, we don't need a variable for debugging. */
5884 /* Otherwise, convert this tree to its GCC equivalent and elaborate it. */
5888 /* Save the expression in case we try to elaborate this entity again. Since
5889 it's not a DECL, don't check it. Don't save if it's a discriminant. */
5894 }
5896 /* Similar, but take a GNU expression and always return a result. */
5898 static tree
5901 {
5902 /* Skip any conversions and simple arithmetics to see if the expression
5903 is a read-only variable.
5904 ??? This really should remain read-only, but we have to think about
5905 the typing of the tree here. */
5906 tree gnu_inner_expr
5912 /* In most cases, we won't see a naked FIELD_DECL because a discriminant
5913 reference will have been replaced with a COMPONENT_REF when the type
5914 is being elaborated. However, there are some cases involving child
5915 types where we will. So convert it to a COMPONENT_REF. We hope it
5916 will be at the highest level of the expression in these cases. */
5922 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
5923 that is read-only, make a variable that is initialized to contain the
5924 bound when the package containing the definition is elaborated. If
5925 this entity is defined at top level and a bound or discriminant value
5926 isn't a constant or a reference to a discriminant, replace the bound
5927 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
5928 rely here on the fact that an expression cannot contain both the
5929 discriminant and some other variable. */
5936 /* If GNU_EXPR contains a discriminant, we can't elaborate a variable. */
5940 /* Now create the variable if we need it. */
5942 gnu_decl
5949 /* We only need to use this variable if we are in global context since GCC
5950 can do the right thing in the local case. */
5955 }
5957 /* Similar, but take an alignment factor and make it explicit in the tree. */
5959 static tree
5962 {
5964 return
5967 gnu_expr,
5968 unit_align),
5970 need_debug),
5971 unit_align);
5972 }
5973 \f
5974 /* Create a record type that contains a SIZE bytes long field of TYPE with a
5975 starting bit position so that it is aligned to ALIGN bits, and leaving at
5976 least ROOM bytes free before the field. BASE_ALIGN is the alignment the
5977 record is guaranteed to get. */
5979 tree
5982 {
5983 /* We will be crafting a record type with one field at a position set to be
5984 the next multiple of ALIGN past record'address + room bytes. We use a
5985 record placeholder to express record'address. */
5989 tree record_addr_st
5992 /* The diagram below summarizes the shape of what we manipulate:
5994 <--------- pos ---------->
5995 { +------------+-------------+-----------------+
5996 record =>{ |############| ... | field (type) |
5997 { +------------+-------------+-----------------+
5998 |<-- room -->|<- voffset ->|<---- size ----->|
5999 o o
6000 | |
6001 record_addr vblock_addr
6003 Every length is in sizetype bytes there, except "pos" which has to be
6004 set as a bit position in the GCC tree for the record. */
6016 /* Compute VOFFSET and then POS. The next byte position multiple of some
6017 alignment after some address is obtained by "and"ing the alignment minus
6018 1 with the two's complement of the address. */
6023 /* POS = (ROOM + VOFFSET) * BIT_PER_UNIT, in bitsizetype. */
6027 bitsize_unit_node);
6029 /* Craft the GCC record representation. We exceptionally do everything
6030 manually here because 1) our generic circuitry is not quite ready to
6031 handle the complex position/size expressions we are setting up, 2) we
6032 have a strong simplifying factor at hand: we know the maximum possible
6033 value of voffset, and 3) we have to set/reset at least the sizes in
6034 accordance with this maximum value anyway, as we need them to convey
6035 what should be "alloc"ated for this type.
6037 Use -1 as the 'addressable' indication for the field to prevent the
6038 creation of a bitfield. We don't need one, it would have damaging
6039 consequences on the alignment computation, and create_field_decl would
6040 make one without this special argument, for instance because of the
6041 complex position expression. */
6052 bitsize_unit_node),
6061 /* Declare it now since it will never be declared otherwise. This is
6062 necessary to ensure that its subtrees are properly marked. */
6066 }
6067 \f
6068 /* Return the result of rounding T up to ALIGN. */
6072 {
6077 }
6079 /* TYPE is a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE that is being used
6080 as the field type of a packed record if IN_RECORD is true, or as the
6081 component type of a packed array if IN_RECORD is false. See if we can
6082 rewrite it either as a type that has a non-BLKmode, which we can pack
6083 tighter in the packed record case, or as a smaller type. If so, return
6084 the new type. If not, return the original type. */
6086 static tree
6088 {
6093 /* No point in doing anything if the size is zero. */
6099 /* Copy the name and flags from the old type to that of the new.
6100 Note that we rely on the pointer equality created here for
6101 TYPE_NAME to look through conversions in various places. */
6108 /* If we are in a record and have a small size, set the alignment to
6109 try for an integral mode. Otherwise set it to try for a smaller
6110 type with BLKmode. */
6112 {
6115 }
6116 else
6117 {
6120 /* Do not try to shrink the size if the RM size is not constant. */
6125 /* Round the RM size up to a unit boundary to get the minimal size
6126 for a BLKmode record. Give up if it's already the size. */
6134 }
6138 /* Now copy the fields, keeping the position and size as we don't want
6139 to change the layout by propagating the packedness downwards. */
6142 {
6153 /* However, for the last field in a not already packed record type
6154 that is of an aggregate type, we need to use the RM size in the
6155 packable version of the record type, see finish_record_type. */
6165 else
6168 new_field
6181 }
6186 /* If this is a padding record, we never want to make the size smaller
6187 than what was specified. For QUAL_UNION_TYPE, also copy the size. */
6189 {
6193 }
6194 else
6195 {
6199 }
6206 /* Try harder to get a packable type if necessary, for example
6207 in case the record itself contains a BLKmode field. */
6212 /* If neither the mode nor the size has shrunk, return the old type. */
6217 }
6218 \f
6219 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
6220 if needed. We have already verified that SIZE and TYPE are large enough.
6221 GNAT_ENTITY is used to name the resulting record and to issue a warning.
6222 IS_COMPONENT_TYPE is true if this is being done for the component type
6223 of an array. IS_USER_TYPE is true if we must complete the original type.
6224 DEFINITION is true if this type is being defined. SAME_RM_SIZE is true
6225 if the RM size of the resulting type is to be set to SIZE too; otherwise,
6226 it's set to the RM size of the original type. */
6228 tree
6232 {
6237 /* If TYPE is a padded type, see if it agrees with any size and alignment
6238 we were given. If so, return the original type. Otherwise, strip
6239 off the padding, since we will either be returning the inner type
6240 or repadding it. If no size or alignment is specified, use that of
6241 the original padded type. */
6243 {
6260 }
6262 /* If the size is either not being changed or is being made smaller (which
6263 is not done here and is only valid for bitfields anyway), show the size
6264 isn't changing. Likewise, clear the alignment if it isn't being
6265 changed. Then return if we aren't doing anything. */
6278 /* If requested, complete the original type and give it a name. */
6285 gnat_entity);
6287 /* We used to modify the record in place in some cases, but that could
6288 generate incorrect debugging information. So make a new record
6289 type and name. */
6304 bitsize_unit_node));
6306 /* If we are changing the alignment and the input type is a record with
6307 BLKmode and a small constant size, try to make a form that has an
6308 integral mode. This might allow the padding record to also have an
6309 integral mode, which will be much more efficient. There is no point
6310 in doing so if a size is specified unless it is also a small constant
6311 size and it is incorrect to do so if we cannot guarantee that the mode
6312 will be naturally aligned since the field must always be addressable.
6314 ??? This might not always be a win when done for a stand-alone object:
6315 since the nominal and the effective type of the object will now have
6316 different modes, a VIEW_CONVERT_EXPR will be required for converting
6317 between them and it might be hard to overcome afterwards, including
6318 at the RTL level when the stand-alone object is accessed as a whole. */
6325 && (!size
6328 {
6333 }
6335 /* Now create the field with the original size. */
6340 /* Do not emit debug info until after the auxiliary record is built. */
6343 /* Set the same size for its RM size if requested; otherwise reuse
6344 the RM size of the original type. */
6347 /* Unless debugging information isn't being written for the input type,
6348 write a record that shows what we are a subtype of and also make a
6349 variable that indicates our size, if still variable. */
6355 {
6381 }
6385 /* If the size was widened explicitly, maybe give a warning. Take the
6386 original size as the maximum size of the input if there was an
6387 unconstrained record involved and round it up to the specified alignment,
6388 if one was specified. */
6396 && size
6405 {
6418 /* Generate message only for entities that come from source, since
6419 if we have an entity created by expansion, the message will be
6420 generated for some other corresponding source entity. */
6422 {
6431 }
6432 }
6435 }
6436 \f
6437 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
6438 the value passed against the list of choices. */
6440 tree
6442 {
6443 Node_Id choice;
6444 Node_Id gnat_temp;
6449 {
6451 {
6456 this_test
6470 this_test
6480 /* This represents either a subtype range, an enumeration
6481 literal, or a constant Ekind says which. If an enumeration
6482 literal or constant, fall through to the next case. */
6485 {
6491 this_test
6498 }
6500 /* ... fall through ... */
6506 single);
6515 }
6518 this_test);
6519 }
6522 }
6523 \f
6524 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
6525 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
6527 static int
6529 {
6530 /* If the field contains an item of variable size, we cannot pack it
6531 because we cannot create temporaries of non-fixed size in case
6532 we need to take the address of the field. See addressable_p and
6533 the notes on the addressability issues for further details. */
6537 /* If the alignment of the record is specified and the field type
6538 is over-aligned, request Storage_Unit alignment for the field. */
6540 {
6543 else
6545 }
6548 }
6550 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
6551 placed in GNU_RECORD_TYPE.
6553 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
6554 record has Component_Alignment of Storage_Unit, -2 if the enclosing
6555 record has a specified alignment.
6557 DEFINITION is true if this field is for a record being defined.
6559 DEBUG_INFO_P is true if we need to write debug information for types
6560 that we may create in the process. */
6562 static tree
6565 {
6569 bool needs_strict_alignment
6573 /* If this field requires strict alignment, we cannot pack it because
6574 it would very likely be under-aligned in the record. */
6577 else
6580 /* If a size is specified, use it. Otherwise, if the record type is packed,
6581 use the official RM size. See "Handling of Type'Size Values" in Einfo
6582 for further details. */
6589 else
6592 /* If we have a specified size that is smaller than that of the field's type,
6593 or a position is specified, and the field's type is a record that doesn't
6594 require strict alignment, see if we can get either an integral mode form
6595 of the type or a smaller form. If we can, show a size was specified for
6596 the field if there wasn't one already, so we know to make this a bitfield
6597 and avoid making things wider.
6599 Changing to an integral mode form is useful when the record is packed as
6600 we can then place the field at a non-byte-aligned position and so achieve
6601 tighter packing. This is in addition required if the field shares a byte
6602 with another field and the front-end lets the back-end handle the access
6603 to the field, because GCC cannot handle non-byte-aligned BLKmode fields.
6605 Changing to a smaller form is required if the specified size is smaller
6606 than that of the field's type and the type contains sub-fields that are
6607 padded, in order to avoid generating accesses to these sub-fields that
6608 are wider than the field.
6610 We avoid the transformation if it is not required or potentially useful,
6611 as it might entail an increase of the field's alignment and have ripple
6612 effects on the outer record type. A typical case is a field known to be
6613 byte-aligned and not to share a byte with another field. */
6619 || (gnu_size
6625 {
6628 {
6632 }
6633 }
6635 /* If we are packing the record and the field is BLKmode, round the
6636 size up to a byte boundary. */
6641 {
6642 Entity_Id gnat_parent
6649 /* Ensure the position does not overlap with the parent subtype, if there
6650 is one. This test is omitted if the parent of the tagged type has a
6651 full rep clause since, in this case, component clauses are allowed to
6652 overlay the space allocated for the parent type and the front-end has
6653 checked that there are no overlapping components. */
6655 {
6660 {
6661 post_error_ne_tree
6665 }
6666 }
6668 /* If this field needs strict alignment, ensure the record is
6669 sufficiently aligned and that that position and size are
6670 consistent with the alignment. */
6672 {
6678 {
6680 post_error_ne_tree
6686 post_error_ne_tree
6692 post_error_ne_tree
6698 }
6703 {
6705 post_error_ne_num
6711 post_error_ne_num
6717 post_error_ne_num
6722 else
6726 }
6727 }
6731 }
6733 /* If the record has rep clauses and this is the tag field, make a rep
6734 clause for it as well. */
6737 {
6740 }
6742 else
6745 /* We need to make the size the maximum for the type if it is
6746 self-referential and an unconstrained type. In that case, we can't
6747 pack the field since we can't make a copy to align it. */
6749 && !gnu_size
6752 {
6755 }
6757 /* If a size is specified, adjust the field's type to it. */
6759 {
6760 tree orig_field_type;
6762 /* If the field's type is justified modular, we would need to remove
6763 the wrapper to (better) meet the layout requirements. However we
6764 can do so only if the field is not aliased to preserve the unique
6765 layout and if the prescribed size is not greater than that of the
6766 packed array to preserve the justification. */
6774 gnu_field_type
6782 /* If a padding record was made, declare it now since it will never be
6783 declared otherwise. This is necessary to ensure that its subtrees
6784 are properly marked. */
6789 }
6791 /* Otherwise (or if there was an error), don't specify a position. */
6792 else
6798 /* Now create the decl for the field. */
6799 gnu_field
6810 }
6811 \f
6812 /* Return true if TYPE is a type with variable size, a padding type with a
6813 field of variable size or is a record that has a field such a field. */
6815 static bool
6817 {
6818 tree field;
6837 }
6838 \f
6839 /* qsort comparer for the bit positions of two record components. */
6841 static int
6843 {
6846 const int ret
6850 }
6852 /* Translate and chain the GNAT_COMPONENT_LIST to the GNU_FIELD_LIST, set
6853 the result as the field list of GNU_RECORD_TYPE and finish it up. When
6854 called from gnat_to_gnu_entity during the processing of a record type
6855 definition, the GCC node for the parent, if any, will be the single field
6856 of GNU_RECORD_TYPE and the GCC nodes for the discriminants will be on the
6857 GNU_FIELD_LIST. The other calls to this function are recursive calls for
6858 the component list of a variant and, in this case, GNU_FIELD_LIST is empty.
6860 PACKED is 1 if this is for a packed record, -1 if this is for a record
6861 with Component_Alignment of Storage_Unit, -2 if this is for a record
6862 with a specified alignment.
6864 DEFINITION is true if we are defining this record type.
6866 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
6867 with a rep clause is to be added; in this case, that is all that should
6868 be done with such fields.
6870 CANCEL_ALIGNMENT is true if the alignment should be zeroed before laying
6871 out the record. This means the alignment only serves to force fields to
6872 be bitfields, but not to require the record to be that aligned. This is
6873 used for variants.
6875 ALL_REP is true if a rep clause is present for all the fields.
6877 UNCHECKED_UNION is true if we are building this type for a record with a
6878 Pragma Unchecked_Union.
6880 DEBUG_INFO_P is true if we need to write debug information about the type.
6882 MAYBE_UNUSED is true if this type may be unused in the end; this doesn't
6883 mean that its contents may be unused as well, but only the container. */
6886 static void
6892 {
6899 /* For each component referenced in a component declaration create a GCC
6900 field and add it to the list, skipping pragmas in the GNAT list. */
6906 {
6910 /* If present, the _Parent field must have been created as the single
6911 field of the record type. Put it before any other fields. */
6913 {
6916 }
6917 else
6918 {
6922 /* If this is the _Tag field, put it before any other fields. */
6926 /* If this is the _Controller field, put it before the other
6927 fields except for the _Tag or _Parent field. */
6929 {
6932 }
6934 /* If this is a regular field, put it after the other fields. */
6935 else
6936 {
6941 }
6942 }
6945 }
6947 /* At the end of the component list there may be a variant part. */
6950 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
6951 mutually exclusive and should go in the same memory. To do this we need
6952 to treat each variant as a record whose elements are created from the
6953 component list for the variant. So here we create the records from the
6954 lists for the variants and put them all into the QUAL_UNION_TYPE.
6955 If this is an Unchecked_Union, we make a UNION_TYPE instead or
6956 use GNU_RECORD_TYPE if there are no fields so far. */
6958 {
6962 tree gnu_var_name
6971 gnu_union_name
6974 /* Reuse an enclosing union if all fields are in the variant part
6975 and there is no representation clause on the record, to match
6976 the layout of C unions. There is an associated check below. */
6981 else
6982 {
6983 gnu_union_type
6989 }
6994 {
6996 tree gnu_inner_name;
6997 tree gnu_qual;
7005 /* Set the alignment of the inner type in case we need to make
7006 inner objects into bitfields, but then clear it out so the
7007 record actually gets only the alignment required. */
7011 /* Similarly, if the outer record has a size specified and all
7012 fields have record rep clauses, we can propagate the size
7013 into the variant part. */
7015 {
7019 }
7021 /* Add the fields into the record type for the variant. Note that
7022 we aren't sure to really use it at this point, see below. */
7032 /* If this is an Unchecked_Union and we have exactly one field,
7033 use this field directly to match the layout of C unions. */
7038 else
7039 {
7040 /* Deal with packedness like in gnat_to_gnu_field. */
7041 int field_packed
7044 /* Finalize the record type now. We used to throw away
7045 empty records but we no longer do that because we need
7046 them to generate complete debug info for the variant;
7047 otherwise, the union type definition will be lacking
7048 the fields associated with these empty variants. */
7053 gnu_field
7055 gnu_union_type,
7056 all_rep_and_size
7058 all_rep_and_size
7066 }
7070 }
7072 /* Only make the QUAL_UNION_TYPE if there are non-empty variants. */
7074 {
7078 {
7082 }
7087 /* If GNU_UNION_TYPE is our record type, it means we must have an
7088 Unchecked_Union with no fields. Verify that and, if so, just
7089 return. */
7091 {
7093 && !gnu_field_list
7096 }
7101 /* Deal with packedness like in gnat_to_gnu_field. */
7102 union_field_packed
7105 gnu_union_field
7114 }
7115 }
7117 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
7118 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do
7119 this in a separate pass since we want to handle the discriminants but
7120 can't play with them until we've used them in debugging data above.
7122 ??? If we then reorder them, debugging information will be wrong but
7123 there's nothing that can be done about this at the moment. */
7126 {
7130 {
7133 else
7138 }
7139 else
7141 }
7143 /* If we have any fields in our rep'ed field list and it is not the case that
7144 all the fields in the record have rep clauses and P_REP_LIST is nonzero,
7145 set it and ignore these fields. */
7149 /* Otherwise, sort the fields by bit position and put them into their own
7150 record, before the others, if we also have fields without rep clauses. */
7152 {
7153 tree gnu_rep_type
7159 gnu_field;
7165 /* Put the fields in the list in order of increasing position, which
7166 means we start from the end. */
7169 {
7173 }
7176 {
7178 gnu_field
7183 }
7184 else
7185 {
7188 }
7189 }
7196 }
7197 \f
7198 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
7199 placed into an Esize, Component_Bit_Offset, or Component_Size value
7200 in the GNAT tree. */
7202 static Uint
7204 {
7205 TCode tcode;
7210 /* See if we've already saved the value for this node. */
7212 {
7223 }
7225 /* If we do not return inside this switch, TCODE will be set to the
7226 code to use for a Create_Node operand and LEN (set above) will be
7227 the number of recursive calls for us to make. */
7230 {
7235 /* This may come from a conversion from some smaller type, so ensure
7236 this is in bitsizetype. */
7239 /* For a negative value, build NEGATE_EXPR of the opposite. Such values
7240 appear in expressions containing aligning patterns. Note that, since
7241 sizetype is sign-extended but nonetheless unsigned, we don't directly
7242 use tree_int_cst_sgn. */
7244 {
7247 }
7252 /* The only case we handle here is a simple discriminant reference. */
7260 else
7266 /* Now just list the operations we handle. */
7297 {
7301 }
7303 /* Fall through... */
7307 }
7309 /* Now get each of the operands that's relevant for this code. If any
7310 cannot be expressed as a repinfo node, say we can't. */
7315 {
7319 }
7323 /* Save the result in the cache. */
7325 {
7329 }
7332 }
7334 /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
7335 and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
7336 size and alignment used by Gigi. Prefer SIZE over TYPE_SIZE if non-null.
7337 BY_REF is true if the object is used by reference. */
7339 void
7341 {
7343 {
7346 else
7348 }
7351 {
7360 }
7365 }
7367 /* Return first element of field list whose TREE_PURPOSE is the same as ELEM.
7368 Return NULL_TREE if there is no such element in the list. */
7370 static tree
7372 {
7374 {
7379 }
7381 }
7383 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding GCC type,
7384 set Component_Bit_Offset and Esize of the components to the position and
7385 size used by Gigi. */
7387 static void
7389 {
7390 Entity_Id gnat_field;
7391 tree gnu_list;
7393 /* We operate by first making a list of all fields and their position (we
7394 can get the size easily) and then update all the sizes in the tree. */
7395 gnu_list
7405 {
7407 gnu_list);
7409 {
7410 tree parent_offset;
7413 {
7414 /* In this mode the tag and parent components are not
7415 generated, so we add the appropriate offset to each
7416 component. For a component appearing in the current
7417 extension, the offset is the size of the parent. */
7420 parent_offset
7422 bitsizetype);
7423 else
7425 }
7426 else
7429 Set_Component_Bit_Offset
7431 annotate_value
7435 parent_offset)));
7439 }
7441 {
7442 /* If there is no entry, this is an inherited component whose
7443 position is the same as in the parent type. */
7444 Set_Component_Bit_Offset
7450 }
7451 }
7452 }
7453 \f
7454 /* Scan all fields in GNU_TYPE and return a TREE_LIST where TREE_PURPOSE is
7455 the FIELD_DECL and TREE_VALUE a TREE_VEC containing the byte position, the
7456 value to be placed into DECL_OFFSET_ALIGN and the bit position. The list
7457 of fields is flattened, except for variant parts if DO_NOT_FLATTEN_VARIANT
7458 is set to true. GNU_POS is to be added to the position, GNU_BITPOS to the
7459 bit position, OFFSET_ALIGN is the present offset alignment. GNU_LIST is a
7460 pre-existing list to be chained to the newly created entries. */
7462 static tree
7465 {
7466 tree gnu_field;
7469 gnu_field;
7471 {
7476 unsigned int our_offset_align
7485 /* Recurse on internal fields, flattening the nested fields except for
7486 those in the variant part, if requested. */
7488 {
7492 gnu_list
7496 else
7497 gnu_list
7501 }
7502 }
7505 }
7507 /* Return a TREE_LIST describing the substitutions needed to reflect the
7508 discriminant substitutions from GNAT_TYPE to GNAT_SUBTYPE. They can
7509 be in any order. TREE_PURPOSE gives the tree for the discriminant and
7510 TREE_VALUE is the replacement value. They are in the form of operands
7511 to SUBSTITUTE_IN_EXPR. DEFINITION is true if this is for a definition
7512 of GNAT_SUBTYPE. */
7514 static tree
7516 {
7518 Entity_Id gnat_discrim;
7519 Node_Id gnat_value;
7526 /* Ignore access discriminants. */
7528 {
7532 elaborate_expression
7536 gnu_list);
7537 }
7540 }
7542 /* Scan all fields in QUAL_UNION_TYPE and return a TREE_LIST describing the
7543 variants of QUAL_UNION_TYPE that are still relevant after applying the
7544 substitutions described in SUBST_LIST. TREE_PURPOSE is the type of the
7545 variant and TREE_VALUE is a TREE_VEC containing the field, the new value
7546 of the qualifier and NULL_TREE respectively. GNU_LIST is a pre-existing
7547 list to be chained to the newly created entries. */
7549 static tree
7551 {
7552 tree gnu_field;
7555 gnu_field;
7557 {
7563 /* If the new qualifier is not unconditionally false, its variant may
7564 still be accessed. */
7566 {
7574 /* Recurse on the variant subpart of the variant, if any. */
7580 /* If the new qualifier is unconditionally true, the subsequent
7581 variants cannot be accessed. */
7584 }
7585 }
7588 }
7589 \f
7590 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
7591 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
7592 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
7593 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
7594 for the size of a field. COMPONENT_P is true if we are being called
7595 to process the Component_Size of GNAT_OBJECT. This is used for error
7596 message handling and to indicate to use the object size of GNU_TYPE.
7597 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
7598 it means that a size of zero should be treated as an unspecified size. */
7600 static tree
7603 {
7604 Node_Id gnat_error_node;
7607 /* Return 0 if no size was specified. */
7611 /* Ignore a negative size since that corresponds to our back-annotation. */
7615 /* Find the node to use for errors. */
7622 else
7625 /* Get the size as a tree. Issue an error if a size was specified but
7626 cannot be represented in sizetype. */
7629 {
7632 gnat_object);
7633 else
7635 gnat_object);
7637 }
7639 /* Ignore a zero size if it is not permitted. */
7643 /* The size of objects is always a multiple of a byte. */
7646 {
7650 else
7654 }
7656 /* If this is an integral type or a packed array type, the front-end has
7657 verified the size, so we need not do it here (which would entail
7658 checking against the bounds). However, if this is an aliased object,
7659 it may not be smaller than the type of the object. */
7664 /* If the object is a record that contains a template, add the size of
7665 the template to the specified size. */
7671 /* If a type needs strict alignment, a component of this type in
7672 a packed record cannot be packed and thus uses the type size. */
7675 else
7678 /* Modify the size of the type to be that of the maximum size if it has a
7679 discriminant. */
7683 /* If this is an access type or a fat pointer, the minimum size is that given
7684 by the smallest integral mode that's valid for pointers. */
7686 {
7691 }
7693 /* If the size of the object is a constant, the new size must not be
7694 smaller. */
7698 {
7700 post_error_ne_tree
7703 else
7704 post_error_ne_tree
7709 }
7712 }
7713 \f
7714 /* Similarly, but both validate and process a value of RM size. This
7715 routine is only called for types. */
7717 static void
7719 {
7720 Node_Id gnat_attr_node;
7723 /* Do nothing if no size was specified. */
7727 /* Ignore a negative size since that corresponds to our back-annotation. */
7731 /* Only issue an error if a Value_Size clause was explicitly given.
7732 Otherwise, we'd be duplicating an error on the Size clause. */
7733 gnat_attr_node
7736 /* Get the size as a tree. Issue an error if a size was specified but
7737 cannot be represented in sizetype. */
7740 {
7743 gnat_entity);
7745 }
7747 /* Ignore a zero size unless a Value_Size clause exists, or a size clause
7748 exists, or this is an integer type, in which case the front-end will
7749 have always set it. */
7758 /* If the old size is self-referential, get the maximum size. */
7762 /* If the size of the object is a constant, the new size must not be smaller
7763 (the front-end has verified this for scalar and packed array types). */
7771 && TYPE_PACKED_ARRAY_TYPE_P
7774 {
7776 post_error_ne_tree
7780 }
7782 /* Otherwise, set the RM size proper for integral types... */
7789 /* ...or the Ada size for record and union types. */
7795 }
7796 \f
7797 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
7798 If TYPE is the best type, return it. Otherwise, make a new type. We
7799 only support new integral and pointer types. FOR_BIASED is true if
7800 we are making a biased type. */
7802 static tree
7804 {
7807 tree new_type;
7809 /* If size indicates an error, just return TYPE to avoid propagating
7810 the error. Likewise if it's too large to represent. */
7817 {
7824 /* Integer types with precision 0 are forbidden. */
7828 /* Only do something if the type is not a packed array type and
7829 doesn't already have the proper size. */
7840 else
7849 /* Copy the name to show that it's essentially the same type and
7850 not a subrange type. */
7857 /* Do something if this is a fat pointer, in which case we
7858 may need to return the thin pointer. */
7860 {
7864 return
7865 build_pointer_type_for_mode
7868 }
7872 /* Only do something if this is a thin pointer, in which case we
7873 may need to return the fat pointer. */
7875 return
7881 }
7884 }
7885 \f
7886 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
7887 a type or object whose present alignment is ALIGN. If this alignment is
7888 valid, return it. Otherwise, give an error and return ALIGN. */
7890 static unsigned int
7892 {
7895 Node_Id gnat_error_node;
7897 /* Don't worry about checking alignment if alignment was not specified
7898 by the source program and we already posted an error for this entity. */
7902 /* Post the error on the alignment clause if any. Note, for the implicit
7903 base type of an array type, the alignment clause is on the first
7904 subtype. */
7912 gnat_error_node =
7915 else
7918 /* Within GCC, an alignment is an integer, so we must make sure a value is
7919 specified that fits in that range. Also, there is an upper bound to
7920 alignments we can support/allow. */
7928 {
7932 /* If the default alignment of "double" or larger scalar types is
7933 specifically capped and the new alignment is above the cap, do
7934 not post an error and change the alignment only if there is an
7935 alignment clause; this makes it possible to have the associated
7936 GCC type overaligned by default for performance reasons. */
7938 {
7939 Entity_Id gnat_type
7941 is_capped_double
7943 }
7945 {
7946 Entity_Id gnat_type
7948 is_capped_double
7950 }
7951 else
7955 {
7958 }
7959 else
7960 {
7967 }
7968 }
7969 else
7970 {
7974 }
7977 }
7979 /* Return the smallest alignment not less than SIZE. */
7981 static unsigned int
7983 {
7985 }
7986 \f
7987 /* Verify that OBJECT, a type or decl, is something we can implement
7988 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
7989 if we require atomic components. */
7991 static void
7993 {
7995 Node_Id gnat_node;
7998 tree size;
8000 /* There are three case of what OBJECT can be. It can be a type, in which
8001 case we take the size, alignment and mode from the type. It can be a
8002 declaration that was indirect, in which case the relevant values are
8003 that of the type being pointed to, or it can be a normal declaration,
8004 in which case the values are of the decl. The code below assumes that
8005 OBJECT is either a type or a decl. */
8007 {
8008 /* If this is an anonymous base type, nothing to check. Error will be
8009 reported on the source type. */
8016 }
8018 {
8022 }
8023 else
8024 {
8028 }
8030 /* Consider all floating-point types atomic and any types that that are
8031 represented by integers no wider than a machine word. */
8038 /* For the moment, also allow anything that has an alignment equal
8039 to its size and which is smaller than a word. */
8047 {
8056 }
8061 else
8064 }
8065 \f
8067 /* Helper for the intrin compatibility checks family. Evaluate whether
8068 two types are definitely incompatible. */
8070 static bool
8072 {
8087 {
8094 /* Assume designated types are ok. We'd need to account for char * and
8095 void * variants to do better, which could rapidly get messy and isn't
8096 clearly worth the effort. */
8101 }
8104 }
8106 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8107 on the Ada/builtin argument lists for the INB binding. */
8109 static bool
8111 {
8115 /* Sequence position of the last argument we checked. */
8119 {
8122 /* If one list is shorter than the other, they fail to match. */
8129 /* If we're done with the Ada args and not with the internal builtin
8130 args, or the other way around, complain. */
8133 {
8136 }
8140 {
8144 }
8146 /* Otherwise, check that types match for the current argument. */
8147 argpos ++;
8149 {
8153 }
8157 }
8160 }
8162 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8163 on the Ada/builtin return values for the INB binding. */
8165 static bool
8167 {
8171 /* Accept function imported as procedure, common and convenient. */
8176 /* Check return types compatibility otherwise. Note that this
8177 handles void/void as well. */
8179 {
8183 }
8186 }
8188 /* Check and return whether the Ada and gcc builtin profiles bound by INB are
8189 compatible. Issue relevant warnings when they are not.
8191 This is intended as a light check to diagnose the most obvious cases, not
8192 as a full fledged type compatiblity predicate. It is the programmer's
8193 responsibility to ensure correctness of the Ada declarations in Imports,
8194 especially when binding straight to a compiler internal. */
8196 static bool
8198 {
8199 /* Check compatibility on return values and argument lists, each responsible
8200 for posting warnings as appropriate. Ensure use of the proper sloc for
8201 this purpose. */
8214 }
8215 \f
8216 /* Return a FIELD_DECL node modeled on OLD_FIELD. FIELD_TYPE is its type
8217 and RECORD_TYPE is the type of the parent. If SIZE is nonzero, it is the
8218 specified size for this field. POS_LIST is a position list describing
8219 the layout of OLD_FIELD and SUBST_LIST a substitution list to be applied
8220 to this layout. */
8222 static tree
8225 {
8235 /* If the position is now a constant, we can set it as the position of the
8236 field when we make it. Otherwise, we need to deal with it specially. */
8239 else
8242 new_field
8248 {
8258 }
8266 }
8268 /* Return the REP part of RECORD_TYPE, if any. Otherwise return NULL. */
8270 static tree
8272 {
8275 /* The REP part is the first field, internal, another record, and its name
8276 doesn't start with an underscore (i.e. is not generated by the FE). */
8283 }
8285 /* Return the variant part of RECORD_TYPE, if any. Otherwise return NULL. */
8287 static tree
8289 {
8290 tree field;
8292 /* The variant part is the only internal field that is a qualified union. */
8299 }
8301 /* Return a new variant part modeled on OLD_VARIANT_PART. VARIANT_LIST is
8302 the list of variants to be used and RECORD_TYPE is the type of the parent.
8303 POS_LIST is a position list describing the layout of fields present in
8304 OLD_VARIANT_PART and SUBST_LIST a substitution list to be applied to this
8305 layout. */
8307 static tree
8310 {
8316 /* First create the type of the variant part from that of the old one. */
8320 /* If the position of the variant part is constant, subtract it from the
8321 size of the type of the parent to get the new size. This manual CSE
8322 reduces the code size when not optimizing. */
8324 {
8334 first_bit));
8337 }
8338 else
8341 /* Now finish up the new variants and populate the union type. */
8343 {
8347 /* Skip variants that don't belong to this nesting level. */
8351 /* Retrieve the list of fields already added to the new variant. */
8355 /* If the old variant had a variant subpart, we need to create a new
8356 variant subpart and add it to the field list. */
8360 {
8361 tree new_variant_subpart
8366 }
8368 /* Finish up the new variant and create the field. No need for debug
8369 info thanks to the XVS type. */
8375 new_field
8383 }
8385 /* Finish up the union type and create the variant part. No need for debug
8386 info thanks to the XVS type. */
8392 new_variant_part
8398 /* With multiple discriminants it is possible for an inner variant to be
8399 statically selected while outer ones are not; in this case, the list
8400 of fields of the inner variant is not flattened and we end up with a
8401 qualified union with a single member. Drop the useless container. */
8403 {
8412 }
8415 }
8417 /* Copy the size (and alignment and alias set) from OLD_TYPE to NEW_TYPE,
8418 which are both RECORD_TYPE, after applying the substitutions described
8419 in SUBST_LIST. */
8421 static void
8423 {
8424 tree t;
8448 SET_TYPE_ADA_SIZE
8453 /* Finalize the size. */
8456 }
8457 \f
8458 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a
8459 type with all size expressions that contain F in a PLACEHOLDER_EXPR
8460 updated by replacing F with R.
8462 The function doesn't update the layout of the type, i.e. it assumes
8463 that the substitution is purely formal. That's why the replacement
8464 value R must itself contain a PLACEHOLDER_EXPR. */
8466 tree
8468 {
8469 tree nt;
8474 {
8480 /* First the domain types of arrays. */
8483 {
8495 SET_TYPE_INDEX_TYPE
8499 }
8501 /* Then the subtypes. */
8504 {
8516 }
8531 /* These should never show up here. */
8535 {
8552 }
8557 {
8559 tree field;
8561 /* Start out with no fields, make new fields, and chain them
8562 in. If we haven't actually changed the type of any field,
8563 discard everything we've done and return the old type. */
8568 {
8573 {
8576 }
8580 {
8583 }
8585 /* Do the substitution inside the qualifier, if any. */
8587 {
8590 {
8593 }
8594 }
8601 }
8611 }
8615 }
8616 }
8617 \f
8618 /* Return the RM size of GNU_TYPE. This is the actual number of bits
8619 needed to represent the object. */
8621 tree
8623 {
8624 /* For integral types, we store the RM size explicitly. */
8628 /* Return the RM size of the actual data plus the size of the template. */
8631 return
8636 /* For record types, we store the size explicitly. */
8644 /* For other types, this is just the size. */
8646 }
8647 \f
8648 /* Return the name to be used for GNAT_ENTITY. If a type, create a
8649 fully-qualified name, possibly with type information encoding.
8650 Otherwise, return the name. */
8652 tree
8654 {
8657 }
8659 /* Return an identifier representing the external name to be used for
8660 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
8661 and the specified suffix. */
8663 tree
8665 {
8669 {
8673 }
8674 else
8677 /* A variable using the Stdcall convention lives in a DLL. We adjust
8678 its name to use the jump table, the _imp__NAME contains the address
8679 for the NAME variable. */
8682 {
8688 }
8691 }
8693 /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
8694 string, return a new IDENTIFIER_NODE that is the concatenation of
8695 the name followed by "___" and the specified suffix. */
8697 tree
8699 {
8706 }