| blob | f487e9b5849ab848ae978e40d323daba13e5e1de |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2015, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License along with GCC; see the file COPYING3. If not see *
19 * <http://www.gnu.org/licenses/>. *
20 * *
21 * GNAT was originally developed by the GNAT team at New York University. *
22 * Extensive contributions were provided by Ada Core Technologies Inc. *
23 * *
24 ****************************************************************************/
61 /* "stdcall" and "thiscall" conventions should be processed in a specific way
62 on 32-bit x86/Windows only. The macros below are helpers to avoid having
63 to check for a Windows specific attribute throughout this unit. */
65 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
66 #ifdef TARGET_64BIT
67 #define Has_Stdcall_Convention(E) \
68 (!TARGET_64BIT && Convention (E) == Convention_Stdcall)
69 #define Has_Thiscall_Convention(E) \
70 (!TARGET_64BIT && is_cplusplus_method (E))
71 #else
72 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
73 #define Has_Thiscall_Convention(E) (is_cplusplus_method (E))
74 #endif
75 #else
76 #define Has_Stdcall_Convention(E) 0
77 #define Has_Thiscall_Convention(E) 0
78 #endif
82 /* Stack realignment is necessary for functions with foreign conventions when
83 the ABI doesn't mandate as much as what the compiler assumes - that is, up
84 to PREFERRED_STACK_BOUNDARY.
86 Such realignment can be requested with a dedicated function type attribute
87 on the targets that support it. We define FOREIGN_FORCE_REALIGN_STACK to
88 characterize the situations where the attribute should be set. We rely on
89 compiler configuration settings for 'main' to decide. */
91 #ifdef MAIN_STACK_BOUNDARY
92 #define FOREIGN_FORCE_REALIGN_STACK \
93 (MAIN_STACK_BOUNDARY < PREFERRED_STACK_BOUNDARY)
94 #else
95 #define FOREIGN_FORCE_REALIGN_STACK 0
96 #endif
98 struct incomplete
99 {
101 tree old_type;
102 Entity_Id full_type;
103 };
105 /* These variables are used to defer recursively expanding incomplete types
106 while we are processing an array, a record or a subprogram type. */
110 /* This variable is used to delay expanding From_Limited_With types until the
111 end of the spec. */
115 tree discriminant;
116 tree replacement;
121 /* The type of the variant. */
122 tree type;
124 /* The associated field. */
125 tree field;
127 /* The value of the qualifier. */
128 tree qual;
130 /* The type of the variant after transformation. */
131 tree new_type;
135 /* A hash table used to cache the result of annotate_value. */
138 {
141 {
143 }
147 {
149 }
151 static void
153 {
159 else
161 }
162 };
214 /* The relevant constituents of a subprogram binding to a GCC builtin. Used
215 to pass around calls performing profile compatibility checks. */
224 \f
225 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
226 entity, return the equivalent GCC tree for that entity (a ..._DECL node)
227 and associate the ..._DECL node with the input GNAT defining identifier.
229 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
230 initial value (in GCC tree form). This is optional for a variable. For
231 a renamed entity, GNU_EXPR gives the object being renamed.
233 DEFINITION is nonzero if this call is intended for a definition. This is
234 used for separate compilation where it is necessary to know whether an
235 external declaration or a definition must be created if the GCC equivalent
236 was not created previously. The value of 1 is normally used for a nonzero
237 DEFINITION, but a value of 2 is used in special circumstances, defined in
238 the code. */
240 tree
242 {
243 /* Contains the kind of the input GNAT node. */
245 /* True if this is a type. */
247 /* True if debug info is requested for this entity. */
249 /* True if this entity is to be considered as imported. */
250 const bool imported_p
252 /* For a type, contains the equivalent GNAT node to be used in gigi. */
254 /* Temporary used to walk the GNAT tree. */
255 Entity_Id gnat_temp;
256 /* Contains the GCC DECL node which is equivalent to the input GNAT node.
257 This node will be associated with the GNAT node by calling at the end
258 of the `switch' statement. */
260 /* Contains the GCC type to be used for the GCC node. */
262 /* Contains the GCC size tree to be used for the GCC node. */
264 /* Contains the GCC name to be used for the GCC node. */
265 tree gnu_entity_name;
266 /* True if we have already saved gnu_decl as a GNAT association. */
268 /* True if we incremented defer_incomplete_level. */
270 /* True if we incremented force_global. */
272 /* True if we should check to see if elaborated during processing. */
274 /* True if we made GNU_DECL and its type here. */
276 /* Size and alignment of the GCC node, if meaningful. */
278 /* Contains the list of attributes directly attached to the entity. */
281 /* Since a use of an Itype is a definition, process it as such if it
282 is not in a with'ed unit. */
284 && is_type
288 {
289 /* Ensure that we are in a subprogram mentioned in the Scope chain of
290 this entity, our current scope is global, or we encountered a task
291 or entry (where we can't currently accurately check scoping). */
294 {
297 }
302 {
307 gnat_temp
319 && (current_function_decl
321 {
324 }
325 }
327 /* This abort means the Itype has an incorrect scope, i.e. that its
328 scope does not correspond to the subprogram it is declared in. */
330 }
332 /* If we've already processed this entity, return what we got last time.
333 If we are defining the node, we should not have already processed it.
334 In that case, we will abort below when we try to save a new GCC tree
335 for this object. We also need to handle the case of getting a dummy
336 type when a Full_View exists but be careful so as not to trigger its
337 premature elaboration. */
340 {
349 {
350 gnu_decl
354 }
357 }
359 /* If this is a numeric or enumeral type, or an access type, a nonzero Esize
360 must be specified unless it was specified by the programmer. Exceptions
361 are for access-to-protected-subprogram types and all access subtypes, as
362 another GNAT type is used to lay out the GCC type for them. */
373 /* The RM size must be specified for all discrete and fixed-point types. */
377 /* If we get here, it means we have not yet done anything with this entity.
378 If we are not defining it, it must be a type or an entity that is defined
379 elsewhere or externally, otherwise we should have defined it already. */
381 || type_annotate_only
382 || is_type
389 /* Get the name of the entity and set up the line number and filename of
390 the original definition for use in any decl we make. Make sure we do not
391 inherit another source location. */
397 /* For cases when we are not defining (i.e., we are referencing from
398 another compilation unit) public entities, show we are at global level
399 for the purpose of computing scopes. Don't do this for components or
400 discriminants since the relevant test is whether or not the record is
401 being defined. */
409 /* Handle any attributes directly attached to the entity. */
413 /* Do some common processing for types. */
415 {
416 /* Compute the equivalent type to be used in gigi. */
419 /* Machine_Attributes on types are expected to be propagated to
420 subtypes. The corresponding Gigi_Rep_Items are only attached
421 to the first subtype though, so we handle the propagation here. */
428 /* Compute a default value for the size of an elementary type. */
430 {
440 else
445 }
446 }
449 {
452 {
453 /* The GNAT record where the component was defined. */
456 /* If the entity is a discriminant of an extended tagged type used to
457 rename a discriminant of the parent type, return the latter. */
460 {
461 gnu_decl
466 }
468 /* If the entity is an inherited component (in the case of extended
469 tagged record types), just return the original entity, which must
470 be a FIELD_DECL. Likewise for discriminants. If the entity is a
471 non-girder discriminant (in the case of derived untagged record
472 types), return the stored discriminant it renames. */
475 {
476 gnu_decl
481 }
483 /* Otherwise, if we are not defining this and we have no GCC type
484 for the containing record, make one for it. Then we should
485 have made our own equivalent. */
487 {
488 /* ??? If this is in a record whose scope is a protected
489 type and we have an Original_Record_Component, use it.
490 This is a workaround for major problems in protected type
491 handling. */
495 {
496 gnu_decl
502 }
508 }
510 else
511 /* Here we have no GCC type and this is a reference rather than a
512 definition. This should never happen. Most likely the cause is
513 reference before declaration in the GNAT tree for gnat_entity. */
515 }
518 /* Ignore constant definitions already marked with the error node. See
519 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
521 && gnu_expr
524 {
527 }
529 /* Ignore deferred constant definitions without address clause since
530 they are processed fully in the front-end. If No_Initialization
531 is set, this is not a deferred constant but a constant whose value
532 is built manually. And constants that are renamings are handled
533 like variables. */
535 && !gnu_expr
539 {
543 }
545 /* If this is a use of a deferred constant without address clause,
546 get its full definition. */
550 {
551 gnu_decl
555 }
557 /* If we have a constant that we are not defining, get the expression it
558 was defined to represent. This is necessary to avoid generating dumb
559 elaboration code in simple cases, but we may throw it away later if it
560 is not a constant. But do not retrieve it if it is an allocator since
561 the designated type might still be dummy at this point. */
567 {
571 /* The expression may contain N_Expression_With_Actions nodes and
572 thus object declarations from other units. In this case, even
573 though the expression will eventually be discarded since not a
574 constant, the declarations would be stuck either in the global
575 varpool or in the current scope. Therefore we force the local
576 context and create a fake scope that we'll zap at the end. */
578 {
581 }
591 }
593 /* ... fall through ... */
599 {
600 /* Always create a variable for volatile objects and variables seen
601 constant but with a Linker_Section pragma. */
602 bool const_flag
619 tree gnu_object_size;
622 {
626 else
628 }
630 /* Get the type after elaborating the renamed object. */
633 /* If this is a standard exception definition, then use the standard
634 exception type. This is necessary to make sure that imported and
635 exported views of exceptions are properly merged in LTO mode. */
640 /* For a debug renaming declaration, build a debug-only entity. */
642 {
643 /* Force a non-null value to make sure the symbol is retained. */
647 integer_minus_one_node));
654 }
656 /* If this is a loop variable, its type should be the base type.
657 This is because the code for processing a loop determines whether
658 a normal loop end test can be done by comparing the bounds of the
659 loop against those of the base type, which is presumed to be the
660 size used for computation. But this is not correct when the size
661 of the subtype is smaller than the type. */
665 /* Reject non-renamed objects whose type is an unconstrained array or
666 any object whose type is a dummy type or void. */
671 {
674 force_global--;
676 }
678 /* If an alignment is specified, use it if valid. Note that exceptions
679 are objects but don't have an alignment. We must do this before we
680 validate the size, since the alignment can affect the size. */
682 {
688 /* No point in changing the type if there is an address clause
689 as the final type of the object will be a reference type. */
692 else
693 {
696 gnu_type
700 /* If a padding record was made, declare it now since it will
701 never be declared otherwise. This is necessary to ensure
702 that its subtrees are properly marked. */
706 }
707 }
709 /* If we are defining the object, see if it has a Size and validate it
710 if so. If we are not defining the object and a Size clause applies,
711 simply retrieve the value. We don't want to ignore the clause and
712 it is expected to have been validated already. Then get the new
713 type, if any. */
722 {
723 gnu_type
729 }
731 /* If this object has self-referential size, it must be a record with
732 a default discriminant. We are supposed to allocate an object of
733 the maximum size in this case, unless it is a constant with an
734 initializing expression, in which case we can get the size from
735 that. Note that the resulting size may still be a variable, so
736 this may end up with an indirect allocation. */
739 {
741 {
744 {
745 /* If the initializing expression is itself a constant,
746 despite having a nominal type with self-referential
747 size, we can get the size directly from it. */
749 && TYPE_IS_PADDING_P
753 || DECL_READONLY_ONCE_ELAB
756 else
757 gnu_size
759 }
760 else
762 }
763 /* We may have no GNU_EXPR because No_Initialization is
764 set even though there's an Expression. */
769 gnu_size
771 (Etype
773 else
774 {
777 }
779 /* If we are at global level and the size isn't constant, call
780 elaborate_expression_1 to make a variable for it rather than
781 calculating it each time. */
785 }
787 /* If the size is zero byte, make it one byte since some linkers have
788 troubles with zero-sized objects. If the object will have a
789 template, that will make it nonzero so don't bother. Also avoid
790 doing that for an object renaming or an object with an address
791 clause, as we would lose useful information on the view size
792 (e.g. for null array slices) and we are not allocating the object
793 here anyway. */
805 /* If this is an object with no specified size and alignment, and
806 if either it is atomic or we are not optimizing alignment for
807 space and it is composite and not an exception, an Out parameter
808 or a reference to another object, and the size of its type is a
809 constant, set the alignment to the smallest one which is not
810 smaller than the size, with an appropriate cap. */
819 && !imported_p
823 {
826 /* No point in promoting the alignment if this doesn't prevent
827 BLKmode access to the object, in particular block copy, as
828 this will for example disable the NRV optimization for it.
829 No point in jumping through all the hoops needed in order
830 to support BIGGEST_ALIGNMENT if we don't really have to.
831 So we cap to the smallest alignment that corresponds to
832 a known efficient memory access pattern of the target. */
834 {
837 }
838 else
839 {
842 }
849 else
852 /* But make sure not to under-align the object. */
856 /* And honor the minimum valid atomic alignment, if any. */
857 #ifdef MINIMUM_ATOMIC_ALIGNMENT
860 #endif
861 }
863 /* If the object is set to have atomic components, find the component
864 type and validate it.
866 ??? Note that we ignore Has_Volatile_Components on objects; it's
867 not at all clear what to do in that case. */
869 {
878 }
880 /* If this is an aliased object with an unconstrained array nominal
881 subtype, make a type that includes the template. We will either
882 allocate or create a variable of that type, see below. */
886 {
887 tree gnu_array
889 gnu_type
891 gnu_type,
894 debug_info_p);
895 }
897 /* ??? If this is an object of CW type initialized to a value, try to
898 ensure that the object is sufficient aligned for this value, but
899 without pessimizing the allocation. This is a kludge necessary
900 because we don't support dynamic alignment. */
907 #ifdef MINIMUM_ATOMIC_ALIGNMENT
908 /* If the size is a constant and no alignment is specified, force
909 the alignment to be the minimum valid atomic alignment. The
910 restriction on constant size avoids problems with variable-size
911 temporaries; if the size is variable, there's no issue with
912 atomic access. Also don't do this for a constant, since it isn't
913 necessary and can interfere with constant replacement. Finally,
914 do not do it for Out parameters since that creates an
915 size inconsistency with In parameters. */
925 #endif
927 /* Make a new type with the desired size and alignment, if needed.
928 But do not take into account alignment promotions to compute the
929 size of the object. */
932 {
938 /* If a padding record was made, declare it now since it will
939 never be declared otherwise. This is necessary to ensure
940 that its subtrees are properly marked. */
944 }
946 /* Now check if the type of the object allows atomic access. */
950 /* If this is a renaming, avoid as much as possible to create a new
951 object. However, in some cases, creating it is required because
952 renaming can be applied to objects that are not names in Ada.
953 This processing needs to be applied to the raw expression so as
954 to make it more likely to rename the underlying object. */
956 {
957 /* If the renamed object had padding, strip off the reference to
958 the inner object and reset our type. */
961 /* Strip useless conversions around the object. */
963 {
966 }
968 /* Or else, if the renamed object has an unconstrained type with
969 default discriminant, use the padded type. */
973 /* Case 1: if this is a constant renaming stemming from a function
974 call, treat it as a normal object whose initial value is what
975 is being renamed. RM 3.3 says that the result of evaluating a
976 function call is a constant object. Therefore, it can be the
977 inner object of a constant renaming and the renaming must be
978 fully instantiated, i.e. it cannot be a reference to (part of)
979 an existing object. And treat null expressions, constructors
980 and literals the same way. */
984 /* Expand_Dispatching_Call can prepend a comparison of the tags
985 before the call to "=". */
993 ;
995 /* Case 2: if the renaming entity need not be materialized, use
996 the elaborated renamed expression for the renaming. But this
997 means that the caller is responsible for evaluating the address
998 of the renaming in the correct place for the definition case to
999 instantiate the SAVE_EXPRs. */
1002 {
1005 gnu_decl
1009 /* We cannot evaluate the first arm of a COMPOUND_EXPR in the
1010 correct place for this case, hence the above test. */
1013 /* No DECL_EXPR will be created so the expression needs to be
1014 marked manually because it will likely be shared. */
1018 /* This assertion will fail if the renamed object isn't aligned
1019 enough as to make it possible to honor the alignment set on
1020 the renaming. */
1022 {
1027 }
1033 }
1035 /* Case 3: otherwise, make a constant pointer to the object we
1036 are renaming and attach the object to the pointer after it is
1037 elaborated. The object will be referenced directly instead
1038 of indirectly via the pointer to avoid aliasing problems with
1039 non-addressable entities. The pointer is called a "renaming"
1040 pointer in this case. Note that we also need to preserve the
1041 volatility of the renamed object through the indirection. */
1042 else
1043 {
1047 gnu_type
1056 renamed_obj
1060 /* If we are not defining the entity, the expression will not
1061 be attached through DECL_INITIAL so it needs to be marked
1062 manually because it will likely be shared. Likewise for a
1063 dereference as it will be folded by the ADDR_EXPR below. */
1071 else
1072 {
1073 gnu_expr
1076 gnu_expr
1078 gnu_expr);
1079 }
1080 }
1081 }
1083 /* Make a volatile version of this object's type if we are to make
1084 the object volatile. We also interpret 13.3(19) conservatively
1085 and disallow any optimizations for such a non-constant object. */
1087 || (!const_flag
1090 || imported_p
1093 {
1094 const int quals
1095 = TYPE_QUAL_VOLATILE
1098 }
1100 /* If we are defining an aliased object whose nominal subtype is
1101 unconstrained, the object is a record that contains both the
1102 template and the object. If there is an initializer, it will
1103 have already been converted to the right type, but we need to
1104 create the template if there is no initializer. */
1106 && !gnu_expr
1109 /* Beware that padding might have been introduced above. */
1112 == RECORD_TYPE
1113 && TYPE_CONTAINS_TEMPLATE_P
1115 {
1116 tree template_field
1124 NULL_TREE);
1127 }
1129 /* Convert the expression to the type of the object if need be. */
1133 /* If this is a pointer that doesn't have an initializing expression,
1134 initialize it to NULL, unless the object is imported. */
1137 && !gnu_expr
1141 /* If we are defining the object and it has an Address clause, we must
1142 either get the address expression from the saved GCC tree for the
1143 object if it has a Freeze node, or elaborate the address expression
1144 here since the front-end has guaranteed that the elaboration has no
1145 effects in this case. */
1147 {
1150 tree gnu_address
1156 /* Convert the type of the object to a reference type that can
1157 alias everything as per 13.3(19). */
1158 gnu_type
1162 const_flag
1167 /* If this is an aliased object with an unconstrained array nominal
1168 subtype, then it can overlay only another aliased object with an
1169 unconstrained array nominal subtype and compatible template. */
1173 {
1177 /* This is the pattern built for a regular object. */
1181 /* This is the pattern built for an overaligned object. */
1184 == PLUS_EXPR
1187 gnu_address
1191 else
1192 {
1195 gnat_entity);
1198 }
1199 }
1201 /* If this is a deferred constant, the initializer is attached to
1202 the full view. */
1204 gnu_expr
1205 = gnat_to_gnu
1208 /* If we don't have an initializing expression for the underlying
1209 variable, the initializing expression for the pointer is the
1210 specified address. Otherwise, we have to make a COMPOUND_EXPR
1211 to assign both the address and the initial value. */
1214 else
1215 gnu_expr
1219 NULL_TREE,
1220 gnu_address),
1221 gnu_expr),
1222 gnu_address);
1223 }
1225 /* If it has an address clause and we are not defining it, mark it
1226 as an indirect object. Likewise for Stdcall objects that are
1227 imported. */
1231 {
1232 /* Convert the type of the object to a reference type that can
1233 alias everything as per 13.3(19). */
1234 gnu_type
1239 /* No point in taking the address of an initializing expression
1240 that isn't going to be used. */
1243 /* If it has an address clause whose value is known at compile
1244 time, make the object a CONST_DECL. This will avoid a
1245 useless dereference. */
1247 {
1248 Node_Id gnat_address
1252 {
1255 }
1256 }
1257 }
1259 /* If we are at top level and this object is of variable size,
1260 make the actual type a hidden pointer to the real type and
1261 make the initializer be a memory allocation and initialization.
1262 Likewise for objects we aren't defining (presumed to be
1263 external references from other packages), but there we do
1264 not set up an initialization.
1266 If the object's size overflows, make an allocator too, so that
1267 Storage_Error gets raised. Note that we will never free
1268 such memory, so we presume it never will get allocated. */
1271 || !definition
1273 || (gnu_size
1275 size_binop
1277 bitsize_unit_node)),
1279 || !definition
1281 {
1287 /* In case this was a aliased object whose nominal subtype is
1288 unconstrained, the pointer above will be a thin pointer and
1289 build_allocator will automatically make the template.
1291 If we have a template initializer only (that we made above),
1292 pretend there is none and rely on what build_allocator creates
1293 again anyway. Otherwise (if we have a full initializer), get
1294 the data part and feed that to build_allocator.
1296 If we are elaborating a mutable object, tell build_allocator to
1297 ignore a possibly simpler size from the initializer, if any, as
1298 we must allocate the maximum possible size in this case. */
1300 {
1305 {
1306 gnu_alloc_type
1312 else
1313 gnu_expr
1314 = build_component_ref
1318 }
1323 gnat_entity);
1325 gnu_expr
1328 }
1329 else
1331 }
1333 /* If this object would go into the stack and has an alignment larger
1334 than the largest stack alignment the back-end can honor, resort to
1335 a variable of "aligning type". */
1338 && !static_p
1339 && !imported_p
1341 {
1342 /* Create the new variable. No need for extra room before the
1343 aligned field as this is in automatic storage. */
1344 tree gnu_new_type
1348 tree gnu_new_var
1354 /* Initialize the aligned field if we have an initializer. */
1356 add_stmt_with_node
1358 build_component_ref
1361 gnu_expr),
1362 gnat_entity);
1364 /* And setup this entity as a reference to the aligned field. */
1366 gnu_expr
1367 = build_unary_op
1376 }
1378 /* If this is an aliased object with an unconstrained array nominal
1379 subtype, we make its type a thin reference, i.e. the reference
1380 counterpart of a thin pointer, so it points to the array part.
1381 This is aimed to make it easier for the debugger to decode the
1382 object. Note that we have to do it this late because of the
1383 couple of allocation adjustments that might be made above. */
1387 {
1388 /* In case the object with the template has already been allocated
1389 just above, we have nothing to do here. */
1391 {
1392 tree gnu_unc_var
1405 }
1407 tree gnu_array
1409 gnu_type
1411 }
1416 /* Convert the expression to the type of the object if need be. */
1420 /* If this name is external or a name was specified, use it, but don't
1421 use the Interface_Name with an address clause (see cd30005). */
1428 /* If this is an aggregate constant initialized to a constant, force it
1429 to be statically allocated. This saves an initialization copy. */
1431 && const_flag
1440 /* Deal with a pragma Linker_Section on a constant or variable. */
1446 /* Now create the variable or the constant and set various flags. */
1447 gnu_decl
1456 /* If we are defining an Out parameter and optimization isn't enabled,
1457 create a fake PARM_DECL for debugging purposes and make it point to
1458 the VAR_DECL. Suppress debug info for the latter but make sure it
1459 will live in memory so that it can be accessed from within the
1460 debugger through the PARM_DECL. */
1462 && definition
1463 && debug_info_p
1464 && !optimize
1466 {
1473 }
1475 /* If this is a loop parameter, set the corresponding flag. */
1479 /* If this is a renaming pointer, attach the renamed object to it. */
1483 /* If this is a constant and we are defining it or it generates a real
1484 symbol at the object level and we are referencing it, we may want
1485 or need to have a true variable to represent it:
1486 - if optimization isn't enabled, for debugging purposes,
1487 - if the constant is public and not overlaid on something else,
1488 - if its address is taken,
1489 - if either itself or its type is aliased. */
1498 {
1499 tree gnu_corr_var
1503 gnat_entity);
1507 /* As debugging information will be generated for the variable,
1508 do not generate debugging information for the constant. */
1511 else
1513 }
1515 /* If this is a constant, even if we don't need a true variable, we
1516 may need to avoid returning the initializer in every case. That
1517 can happen for the address of a (constant) constructor because,
1518 upon dereferencing it, the constructor will be reinjected in the
1519 tree, which may not be valid in every case; see lvalue_required_p
1520 for more details. */
1524 /* If this object is declared in a block that contains a block with an
1525 exception handler, and we aren't using the GCC exception mechanism,
1526 we must force this variable in memory in order to avoid an invalid
1527 optimization. */
1532 /* If this is a local variable with non-BLKmode and aggregate type,
1533 and optimization isn't enabled, then force it in memory so that
1534 a register won't be allocated to it with possible subparts left
1535 uninitialized and reaching the register allocator. */
1545 /* If we are defining an object with variable size or an object with
1546 fixed size that will be dynamically allocated, and we are using the
1547 setjmp/longjmp exception mechanism, update the setjmp buffer. */
1560 gnat_entity);
1562 /* Back-annotate Esize and Alignment of the object if not already
1563 known. Note that we pick the values of the type, not those of
1564 the object, to shield ourselves from low-level platform-dependent
1565 adjustments like alignment promotion. This is both consistent with
1566 all the treatment above, where alignment and size are set on the
1567 type of the object and not on the object directly, and makes it
1568 possible to support all confirming representation clauses. */
1570 used_by_ref);
1571 }
1575 /* Return a TYPE_DECL for "void" that we previously made. */
1580 /* A special case: for the types Character and Wide_Character in
1581 Standard, we do not list all the literals. So if the literals
1582 are not specified, make this an unsigned integer type. */
1584 {
1588 /* Set TYPE_STRING_FLAG for Character and Wide_Character types.
1589 This is needed by the DWARF-2 back-end to distinguish between
1590 unsigned integer types and character types. */
1592 }
1593 else
1594 {
1595 /* We have a list of enumeral constants in First_Literal. We make a
1596 CONST_DECL for each one and build into GNU_LITERAL_LIST the list
1597 to be placed into TYPE_FIELDS. Each node is itself a TREE_LIST
1598 whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
1599 value of the literal. But when we have a regular boolean type, we
1600 simplify this a little by using a BOOLEAN_TYPE. */
1605 Entity_Id gnat_literal;
1618 {
1619 tree gnu_value
1621 tree gnu_literal
1625 /* Do not generate debug info for individual enumerators. */
1628 gnu_list
1630 }
1635 /* Note that the bounds are updated at the end of this function
1636 to avoid an infinite recursion since they refer to the type. */
1638 }
1644 /* For integer types, just make a signed type the appropriate number
1645 of bits. */
1650 {
1651 /* For modular types, make the unsigned type of the proper number
1652 of bits and then set up the modulus, if required. */
1655 /* Packed Array Impl. Types are supposed to be subtypes only. */
1660 /* Get the modulus in this type. If it overflows, assume it is because
1661 it is equal to 2**Esize. Note that there is no overflow checking
1662 done on unsigned type, so we detect the overflow by looking for
1663 a modulus of zero, which is otherwise invalid. */
1667 {
1672 }
1674 /* If the upper bound is not maximal, make an extra subtype. */
1677 {
1684 }
1685 }
1694 /* For integral subtypes, we make a new INTEGER_TYPE. Note that we do
1695 not want to call create_range_type since we would like each subtype
1696 node to be distinct. ??? Historically this was in preparation for
1697 when memory aliasing is implemented, but that's obsolete now given
1698 the call to relate_alias_sets below.
1700 The TREE_TYPE field of the INTEGER_TYPE points to the base type;
1701 this fact is used by the arithmetic conversion functions.
1703 We elaborate the Ancestor_Subtype if it is not in the current unit
1704 and one of our bounds is non-static. We do this to ensure consistent
1705 naming in the case where several subtypes share the same bounds, by
1706 elaborating the first such subtype first, thus using its name. */
1715 /* Set the precision to the Esize except for bit-packed arrays. */
1720 /* This should be an unsigned type if the base type is unsigned or
1721 if the lower bound is constant and non-negative or if the type
1722 is biased. */
1727 else
1731 SET_TYPE_RM_MIN_VALUE
1736 SET_TYPE_RM_MAX_VALUE
1744 /* Inherit our alias set from what we're a subtype of. Subtypes
1745 are not different types and a pointer can designate any instance
1746 within a subtype hierarchy. */
1749 /* One of the above calls might have caused us to be elaborated,
1750 so don't blow up if so. */
1752 {
1755 }
1757 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
1761 /* For a packed array, make the original array type a parallel type. */
1765 discrete_type:
1767 /* We have to handle clauses that under-align the type specially. */
1770 && Present
1773 {
1777 }
1779 /* If the type we are dealing with represents a bit-packed array,
1780 we need to have the bits left justified on big-endian targets
1781 and right justified on little-endian targets. We also need to
1782 ensure that when the value is read (e.g. for comparison of two
1783 such values), we only get the good bits, since the unused bits
1784 are uninitialized. Both goals are accomplished by wrapping up
1785 the modular type in an enclosing record type. */
1788 {
1791 /* Set the RM size before wrapping up the original type. */
1796 /* Create a stripped-down declaration, mainly for debugging. */
1798 gnat_entity);
1800 /* Now save it and build the enclosing record type. */
1810 /* Propagate the alignment of the modular type to the record type,
1811 unless there is an alignment clause that under-aligns the type.
1812 This means that bit-packed arrays are given "ceil" alignment for
1813 their size by default, which may seem counter-intuitive but makes
1814 it possible to overlay them on modular types easily. */
1820 /* Don't declare the field as addressable since we won't be taking
1821 its address and this would prevent create_field_decl from making
1822 a bitfield. */
1823 gnu_field
1827 /* Do not emit debug info until after the parallel type is added. */
1833 {
1834 /* Make the original array type a parallel type. */
1838 }
1839 }
1841 /* If the type we are dealing with has got a smaller alignment than the
1842 natural one, we need to wrap it up in a record type and misalign the
1843 latter; we reuse the padding machinery for this purpose. Note that,
1844 even if the record type is marked as packed because of misalignment,
1845 we don't pack the field so as to give it the size of the type. */
1847 {
1850 /* Set the RM size before wrapping up the type. */
1854 /* Create a stripped-down declaration, mainly for debugging. */
1856 gnat_entity);
1858 /* Now save it and build the enclosing record type. */
1870 /* Don't declare the field as addressable since we won't be taking
1871 its address and this would prevent create_field_decl from making
1872 a bitfield. */
1873 gnu_field
1881 }
1886 /* The type of the Low and High bounds can be our type if this is
1887 a type from Standard, so set them at the end of the function. */
1894 /* See the E_Signed_Integer_Subtype case for the rationale. */
1911 SET_TYPE_RM_MIN_VALUE
1916 SET_TYPE_RM_MAX_VALUE
1921 /* Inherit our alias set from what we're a subtype of, as for
1922 integer subtypes. */
1925 /* One of the above calls might have caused us to be elaborated,
1926 so don't blow up if so. */
1930 /* Array Types and Subtypes
1932 Unconstrained array types are represented by E_Array_Type and
1933 constrained array types are represented by E_Array_Subtype. There
1934 are no actual objects of an unconstrained array type; all we have
1935 are pointers to that type.
1937 The following fields are defined on array types and subtypes:
1939 Component_Type Component type of the array.
1940 Number_Dimensions Number of dimensions (an int).
1941 First_Index Type of first index. */
1944 {
1945 const bool convention_fortran_p
1948 tree gnu_template_type;
1949 tree gnu_ptr_template;
1956 tree comp_type;
1958 /* Create the type for the component now, as it simplifies breaking
1959 type reference loops. */
1960 comp_type
1963 {
1964 /* As a side effect, the type may have been translated. */
1967 }
1969 /* We complete an existing dummy fat pointer type in place. This both
1970 avoids further complex adjustments in update_pointer_to and yields
1971 better debugging information in DWARF by leveraging the support for
1972 incomplete declarations of "tagged" types in the DWARF back-end. */
1975 {
1978 /* Save the contents of the dummy type for update_pointer_to. */
1980 gnu_ptr_template =
1983 }
1984 else
1985 {
1989 }
1991 /* Make a node for the array. If we are not defining the array
1992 suppress expanding incomplete types. */
1996 {
1997 defer_incomplete_level++;
1999 }
2001 /* Build the fat pointer type. Use a "void *" object instead of
2002 a pointer to the array type since we don't have the array type
2003 yet (it will reference the fat pointer via the bounds). */
2004 tem
2012 {
2013 /* We are going to lay it out again so reset the alias set. */
2019 {
2022 }
2023 }
2024 else
2025 {
2028 }
2030 /* Build a reference to the template from a PLACEHOLDER_EXPR that
2031 is the fat pointer. This will be used to access the individual
2032 fields once we build them. */
2036 gnu_template_reference
2041 /* Now create the GCC type for each index and add the fields for that
2042 index to the template. */
2048 {
2050 tree gnu_index_base_type
2055 /* Make the FIELD_DECLs for the low and high bounds of this
2056 type and then make extractions of these fields from the
2057 template. */
2060 gnu_index_base_type,
2068 gnu_index_base_type,
2076 /* We can't use build_component_ref here since the template type
2077 isn't complete yet. */
2080 NULL_TREE);
2083 NULL_TREE);
2089 /* Compute the size of this dimension. See the E_Array_Subtype
2090 case below for the rationale. */
2091 gnu_high
2095 gnu_max,
2098 /* Make a range type with the new range in the Ada base type.
2099 Then make an index type with the size range in sizetype. */
2103 gnu_orig_min,
2104 gnu_orig_max),
2105 gnat_entity);
2107 /* Update the maximum size of the array in elements. */
2109 {
2111 tree gnu_min
2113 tree gnu_max
2115 tree gnu_this_max
2122 else
2123 gnu_max_size
2125 }
2129 }
2131 /* Install all the fields into the template. */
2136 gnu_template_fields
2139 debug_info_p);
2142 /* If Component_Size is not already specified, annotate it with the
2143 size of the component. */
2148 /* Compute the maximum size of the array in units and bits. */
2150 {
2156 }
2157 else
2160 /* Now build the array type. */
2163 {
2170 }
2172 /* If an alignment is specified, use it if valid. But ignore it
2173 for the original type of packed array types. If the alignment
2174 was requested with an explicit alignment clause, state so. */
2177 {
2183 }
2190 /* Adjust the type of the pointer-to-array field of the fat pointer
2191 and record the aliasing relationships if necessary. */
2196 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2197 corresponding fat pointer. */
2204 /* If the maximum size doesn't overflow, use it. */
2210 {
2215 }
2219 gnat_entity);
2221 /* Give the fat pointer type a name. If this is a packed array, tell
2222 the debugger how to interpret the underlying bits. */
2225 else
2229 gnat_entity);
2231 /* Create the type to be designated by thin pointers: a record type for
2232 the array and its template. We used to shift the fields to have the
2233 template at a negative offset, but this was somewhat of a kludge; we
2234 now shift thin pointer values explicitly but only those which have a
2235 TYPE_UNCONSTRAINED_ARRAY attached to the designated RECORD_TYPE. */
2238 debug_info_p);
2242 }
2247 /* This is the actual data type for array variables. Multidimensional
2248 arrays are implemented as arrays of arrays. Note that arrays which
2249 have sparse enumeration subtypes as index components create sparse
2250 arrays, which is obviously space inefficient but so much easier to
2251 code for now.
2253 Also note that the subtype never refers to the unconstrained array
2254 type, which is somewhat at variance with Ada semantics.
2256 First check to see if this is simply a renaming of the array type.
2257 If so, the result is the array type. */
2261 ;
2262 else
2263 {
2265 const bool convention_fortran_p
2274 /* First create the GCC type for each index and find out whether
2275 special types are needed for debugging information. */
2278 gnat_base_index
2284 {
2287 tree gnu_orig_min
2290 tree gnu_orig_max
2295 tree gnu_base_index_type
2297 tree gnu_base_index_base_type
2299 tree gnu_base_orig_min
2302 tree gnu_base_orig_max
2305 tree gnu_high;
2307 /* See if the base array type is already flat. If it is, we
2308 are probably compiling an ACATS test but it will cause the
2309 code below to malfunction if we don't handle it specially. */
2313 {
2317 }
2319 /* Similarly, if one of the values overflows in sizetype and the
2320 range is null, use 1..0 for the sizetype bounds. */
2325 {
2329 }
2331 /* If the minimum and maximum values both overflow in sizetype,
2332 but the difference in the original type does not overflow in
2333 sizetype, ignore the overflow indication. */
2337 && !TREE_OVERFLOW
2340 gnu_orig_max,
2341 gnu_orig_min))))
2342 {
2346 }
2348 /* Compute the size of this dimension in the general case. We
2349 need to provide GCC with an upper bound to use but have to
2350 deal with the "superflat" case. There are three ways to do
2351 this. If we can prove that the array can never be superflat,
2352 we can just use the high bound of the index type. */
2355 /* Bit-Packed Array Impl. Types are never superflat. */
2357 && Is_Bit_Packed_Array
2361 /* Otherwise, if the high bound is constant but the low bound is
2362 not, we use the expression (hb >= lb) ? lb : hb + 1 for the
2363 lower bound. Note that the comparison must be done in the
2364 original type to avoid any overflow during the conversion. */
2367 {
2369 gnu_min
2372 boolean_type_node,
2373 gnu_orig_max,
2374 gnu_orig_min),
2375 gnu_min,
2377 size_one_node));
2378 }
2380 /* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
2381 in all the other cases. Note that, here as well as above,
2382 the condition used in the comparison must be equivalent to
2383 the condition (length != 0). This is relied upon in order
2384 to optimize array comparisons in compare_arrays. Moreover
2385 we use int_const_binop for the shift by 1 if the bound is
2386 constant to avoid any unwanted overflow. */
2387 else
2388 gnu_high
2391 boolean_type_node,
2392 gnu_orig_max,
2393 gnu_orig_min),
2394 gnu_max,
2397 size_one_node)
2399 size_one_node));
2401 /* Reuse the index type for the range type. Then make an index
2402 type with the size range in sizetype. */
2405 gnat_entity);
2407 /* Update the maximum size of the array in elements. Here we
2408 see if any constraint on the index type of the base type
2409 can be used in the case of self-referential bound on the
2410 index type of the subtype. We look for a non-"infinite"
2411 and non-self-referential bound from any type involved and
2412 handle each bound separately. */
2414 {
2417 tree gnu_base_index_base_type
2419 tree gnu_base_base_min
2422 tree gnu_base_base_max
2443 else
2444 {
2445 tree gnu_this_max;
2447 /* Use int_const_binop if the bounds are constant to
2448 avoid any unwanted overflow. */
2451 gnu_this_max
2454 gnu_base_max,
2455 gnu_base_min));
2456 else
2457 gnu_this_max
2460 gnu_base_max,
2461 gnu_base_min));
2463 gnu_max_size
2465 }
2466 }
2468 /* We need special types for debugging information to point to
2469 the index types if they have variable bounds, are not integer
2470 types or are biased. */
2479 }
2481 /* Then flatten: create the array of arrays. For an array type
2482 used to implement a packed array, get the component type from
2483 the original array type since the representation clauses that
2484 can affect it are on the latter. */
2487 {
2492 /* One of the above calls might have caused us to be elaborated,
2493 so don't blow up if so. */
2495 {
2498 }
2499 }
2500 else
2501 {
2503 debug_info_p);
2505 /* One of the above calls might have caused us to be elaborated,
2506 so don't blow up if so. */
2508 {
2511 }
2512 }
2514 /* Compute the maximum size of the array in units and bits. */
2516 {
2522 }
2523 else
2526 /* Now build the array type. */
2528 {
2534 }
2536 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
2540 /* If we are at file level and this is a multi-dimensional array,
2541 we need to make a variable corresponding to the stride of the
2542 inner dimensions. */
2544 {
2545 tree gnu_arr_type;
2550 {
2560 /* ??? For now, store the size as a multiple of the
2561 alignment of the element type in bytes so that we
2562 can see the alignment from the tree. */
2570 /* ??? create_type_decl is not invoked on the inner types so
2571 the MULT_EXPR node built above will never be marked. */
2573 }
2574 }
2576 /* If we need to write out a record type giving the names of the
2577 bounds for debugging purposes, do it now and make the record
2578 type a parallel type. This is not needed for a packed array
2579 since the bounds are conveyed by the original array type. */
2581 && debug_info_p
2583 {
2586 tree gnu_field;
2592 {
2596 /* Make sure to reference the types themselves, and not just
2597 their names, as the debugger may fall back on them. */
2603 }
2607 }
2609 /* If this is a packed array type, make the original array type a
2610 parallel type. Otherwise, do it for the base array type if it
2611 isn't artificial to make sure it is kept in the debug info. */
2613 {
2616 else
2617 {
2618 tree gnu_base_decl
2623 }
2624 }
2631 /* If the size is self-referential and the maximum size doesn't
2632 overflow, use it. */
2634 && gnu_max_size
2639 {
2645 }
2647 /* Set our alias set to that of our base type. This gives all
2648 array subtypes the same alias set. */
2651 /* If this is a packed type, make this type the same as the packed
2652 array type, but do some adjusting in the type first. */
2654 {
2655 Entity_Id gnat_index;
2656 tree gnu_inner;
2658 /* First finish the type we had been making so that we output
2659 debugging information for it. */
2662 {
2663 const int quals
2664 = TYPE_QUAL_VOLATILE
2667 }
2668 /* Make it artificial only if the base type was artificial too.
2669 That's sort of "morally" true and will make it possible for
2670 the debugger to look it up by name in DWARF, which is needed
2671 in order to decode the packed array type. */
2672 gnu_decl
2678 /* Save it as our equivalent in case the call below elaborates
2679 this type again. */
2682 gnu_decl
2695 /* We need to attach the index type to the type we just made so
2696 that the actual bounds can later be put into a template. */
2701 {
2703 {
2704 /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
2705 TYPE_MODULUS for modular types so we make an extra
2706 subtype if necessary. */
2708 {
2709 tree gnu_subtype
2718 }
2722 #ifdef ENABLE_CHECKING
2723 /* Check for other cases of overloading. */
2725 #endif
2726 }
2731 SET_TYPE_ACTUAL_BOUNDS
2738 SET_TYPE_ACTUAL_BOUNDS
2744 }
2745 }
2747 else
2748 /* Abort if packed array with no Packed_Array_Impl_Type. */
2750 }
2754 /* Create the type for a string literal. */
2755 {
2756 Entity_Id gnat_full_type
2761 tree gnu_string_array_type
2763 tree gnu_string_index_type
2766 tree gnu_lower_bound
2769 tree gnu_length
2771 gnu_string_index_type);
2772 tree gnu_upper_bound
2774 gnu_lower_bound,
2777 integer_one_node)));
2778 tree gnu_index_type
2782 gnu_lower_bound,
2783 gnu_upper_bound),
2784 gnat_entity);
2786 gnu_type
2789 gnu_index_type);
2793 }
2796 /* Record Types and Subtypes
2798 The following fields are defined on record types:
2800 Has_Discriminants True if the record has discriminants
2801 First_Discriminant Points to head of list of discriminants
2802 First_Entity Points to head of list of fields
2803 Is_Tagged_Type True if the record is tagged
2805 Implementation of Ada records and discriminated records:
2807 A record type definition is transformed into the equivalent of a C
2808 struct definition. The fields that are the discriminants which are
2809 found in the Full_Type_Declaration node and the elements of the
2810 Component_List found in the Record_Type_Definition node. The
2811 Component_List can be a recursive structure since each Variant of
2812 the Variant_Part of the Component_List has a Component_List.
2814 Processing of a record type definition comprises starting the list of
2815 field declarations here from the discriminants and the calling the
2816 function components_to_record to add the rest of the fields from the
2817 component list and return the gnu type node. The function
2818 components_to_record will call itself recursively as it traverses
2819 the tree. */
2823 {
2824 gnu_type
2825 = build_complex_type
2826 (get_unpadded_type
2829 (Component_List
2830 (Type_Definition
2834 }
2836 {
2839 Node_Id gnat_constr;
2840 Entity_Id gnat_field;
2842 tree gnu_get_parent;
2843 /* Set PACKED in keeping with gnat_to_gnu_field. */
2844 const int packed
2856 const bool is_extension
2862 /* See if all fields have a rep clause. Stop when we find one
2863 that doesn't. */
2871 {
2874 }
2876 /* If this is a record extension, go a level further to find the
2877 record definition. Also, verify we have a Parent_Subtype. */
2879 {
2886 }
2888 /* Make a node for the record. If we are not defining the record,
2889 suppress expanding incomplete types. */
2898 {
2899 defer_incomplete_level++;
2901 }
2903 /* If both a size and rep clause was specified, put the size in
2904 the record type now so that it can get the proper mode. */
2909 /* Always set the alignment here so that it can be used to
2910 set the mode, if it is making the alignment stricter. If
2911 it is invalid, it will be checked again below. If this is to
2912 be Atomic, choose a default alignment of a word unless we know
2913 the size and it's smaller. */
2918 {
2922 }
2923 /* If a type needs strict alignment, the minimum size will be the
2924 type size instead of the RM size (see validate_size). Cap the
2925 alignment, lest it causes this type size to become too large. */
2927 {
2932 }
2933 else
2936 /* If we have a Parent_Subtype, make a field for the parent. If
2937 this record has rep clauses, force the position to zero. */
2939 {
2942 tree gnu_parent;
2944 /* A major complexity here is that the parent subtype will
2945 reference our discriminants in its Stored_Constraint list.
2946 But those must reference the parent component of this record
2947 which is precisely of the parent subtype we have not built yet!
2948 To break the circle we first build a dummy COMPONENT_REF which
2949 represents the "get to the parent" operation and initialize
2950 each of those discriminants to a COMPONENT_REF of the above
2951 dummy parent referencing the corresponding discriminant of the
2952 base type of the parent subtype. */
2957 gnu_dummy_parent_type),
2958 NULL_TREE);
2965 {
2966 tree gnu_field
2969 save_gnu_tree
2974 }
2976 /* Then we build the parent subtype. If it has discriminants but
2977 the type itself has unknown discriminants, this means that it
2978 doesn't contain information about how the discriminants are
2979 derived from those of the ancestor type, so it cannot be used
2980 directly. Instead it is built by cloning the parent subtype
2981 of the underlying record view of the type, for which the above
2982 derivation of discriminants has been made explicit. */
2985 {
2988 /* If we are defining the type, the underlying record
2989 view must already have been elaborated at this point.
2990 Otherwise do it now as its parent subtype cannot be
2991 technically elaborated on its own. */
2994 else
2999 /* Substitute the "get to the parent" of the type for that
3000 of its underlying record view in the cloned type. */
3005 {
3007 tree gnu_ref
3010 gnu_parent
3012 }
3013 }
3014 else
3017 /* The parent field needs strict alignment so, if it is to
3018 be created with a component clause below, then we need
3019 to apply the same adjustment as in gnat_to_gnu_field. */
3023 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
3024 initially built. The discriminants must reference the fields
3025 of the parent subtype and not those of its base type for the
3026 placeholder machinery to properly work. */
3028 {
3029 /* The actual parent subtype is the full view. */
3031 {
3034 else
3036 }
3042 {
3043 Entity_Id field;
3052 }
3053 }
3055 /* The "get to the parent" COMPONENT_REF must be given its
3056 proper type... */
3059 /* ...and reference the _Parent field of this record. */
3060 gnu_field
3063 has_rep
3065 has_rep
3071 }
3073 /* Make the fields for the discriminants and put them into the record
3074 unless it's an Unchecked_Union. */
3079 {
3080 /* If this is a record extension and this discriminant is the
3081 renaming of another discriminant, we've handled it above. */
3086 gnu_field
3088 debug_info_p);
3090 /* Make an expression using a PLACEHOLDER_EXPR from the
3091 FIELD_DECL node just created and link that with the
3092 corresponding GNAT defining identifier. */
3100 {
3103 }
3104 }
3106 /* If we have a derived untagged type that renames discriminants in
3107 the root type, the (stored) discriminants are a just copy of the
3108 discriminants of the root type. This means that any constraints
3109 added by the renaming in the derivation are disregarded as far
3110 as the layout of the derived type is concerned. To rescue them,
3111 we change the type of the (stored) discriminants to a subtype
3112 with the bounds of the type of the visible discriminants. */
3114 && !is_extension
3120 /* Ignore access discriminants. */
3123 {
3127 /* If the scope of the discriminant is not the record type,
3128 this means that we're processing the implicit full view
3129 of a type derived from a private discriminated type: in
3130 this case, the Stored_Constraint list is simply copied
3131 from the partial view, see Build_Derived_Private_Type.
3132 So we need to retrieve the corresponding discriminant
3133 of the implicit full view, otherwise we will abort. */
3135 {
3136 Entity_Id field;
3145 }
3148 gnu_ref
3152 /* GNU_REF must be an expression using a PLACEHOLDER_EXPR built
3153 just above for one of the stored discriminants. */
3157 {
3159 tree gnu_subtype
3170 }
3171 }
3173 /* Add the fields into the record type and finish it up. */
3181 /* Fill in locations of fields. */
3184 /* If there are any entities in the chain corresponding to components
3185 that we did not elaborate, ensure we elaborate their types if they
3186 are Itypes. */
3196 /* If this is a record type associated with an exception definition,
3197 equate its fields to those of the standard exception type. This
3198 will make it possible to convert between them. */
3200 {
3201 tree gnu_std_field;
3204 gnu_field;
3209 }
3210 }
3214 /* If an equivalent type is present, that is what we should use.
3215 Otherwise, fall through to handle this like a record subtype
3216 since it may have constraints. */
3218 {
3222 }
3224 /* ... fall through ... */
3227 /* If Cloned_Subtype is Present it means this record subtype has
3228 identical layout to that type or subtype and we should use
3229 that GCC type for this one. The front end guarantees that
3230 the component list is shared. */
3232 {
3237 }
3239 /* Otherwise, first ensure the base type is elaborated. Then, if we are
3240 changing the type, make a new type with each field having the type of
3241 the field in the new subtype but the position computed by transforming
3242 every discriminant reference according to the constraints. We don't
3243 see any difference between private and non-private type here since
3244 derivations from types should have been deferred until the completion
3245 of the private type. */
3246 else
3247 {
3249 tree gnu_base_type;
3252 {
3253 defer_incomplete_level++;
3255 }
3257 gnu_base_type
3261 {
3264 }
3266 /* If this is a record subtype associated with a dispatch table,
3267 strip the suffix. This is necessary to make sure 2 different
3268 subtypes associated with the imported and exported views of a
3269 dispatch table are properly merged in LTO mode. */
3271 {
3278 }
3280 /* When the subtype has discriminants and these discriminants affect
3281 the initial shape it has inherited, factor them in. But for an
3282 Unchecked_Union (it must be an Itype), just return the type.
3283 We can't just test Is_Constrained because private subtypes without
3284 discriminants of types with discriminants with default expressions
3285 are Is_Constrained but aren't constrained! */
3292 {
3298 Entity_Id gnat_field;
3306 /* Set the size, alignment and alias set of the new type to
3307 match that of the old one, doing required substitutions. */
3309 gnu_subst_list);
3313 else
3316 /* Look for REP and variant parts in the base type. */
3320 /* If there is a variant part, we must compute whether the
3321 constraints statically select a particular variant. If
3322 so, we simply drop the qualified union and flatten the
3323 list of fields. Otherwise we'll build a new qualified
3324 union for the variants that are still relevant. */
3326 {
3330 gnu_variant_list
3332 gnu_subst_list,
3333 vNULL);
3335 /* If all the qualifiers are unconditionally true, the
3336 innermost variant is statically selected. */
3340 {
3343 }
3345 /* Otherwise, create the new variants. */
3348 {
3351 tree suffix
3353 IDENTIFIER_POINTER
3359 gnu_subst_list);
3361 }
3362 }
3363 else
3364 {
3367 }
3369 /* Make a list of fields and their position in the base type. */
3370 gnu_pos_list
3377 /* Now go down every component in the subtype and compute its
3378 size and position from those of the component in the base
3379 type and from the constraints of the subtype. */
3387 && Underlying_Type
3390 {
3392 Entity_Id gnat_old_field
3394 tree gnu_old_field
3400 /* If the type is the same, retrieve the GCC type from the
3401 old field to take into account possible adjustments. */
3404 else
3407 /* If there was a component clause, the field types must be
3408 the same for the type and subtype, so copy the data from
3409 the old field to avoid recomputation here. Also if the
3410 field is justified modular and the optimization in
3411 gnat_to_gnu_field was applied. */
3417 {
3420 }
3422 /* If the old field was packed and of constant size, we
3423 have to get the old size here, as it might differ from
3424 what the Etype conveys and the latter might overlap
3425 onto the following field. Try to arrange the type for
3426 possible better packing along the way. */
3430 {
3435 gnu_field_type
3437 }
3439 else
3442 /* If the context of the old field is the base type or its
3443 REP part (if any), put the field directly in the new
3444 type; otherwise look up the context in the variant list
3445 and put the field either in the new type if there is a
3446 selected variant or in one of the new variants. */
3448 || (gnu_rep_part
3451 else
3452 {
3455 tree rep_part;
3463 {
3466 else
3468 }
3469 else
3470 /* The front-end may pass us "ghost" components if
3471 it fails to recognize that a constrained subtype
3472 is statically constrained. Discard them. */
3474 }
3476 /* Now create the new field modeled on the old one. */
3477 gnu_field
3483 /* Put it in one of the new variants directly. */
3485 {
3488 }
3490 /* To match the layout crafted in components_to_record,
3491 if this is the _Tag or _Parent field, put it before
3492 any other fields. */
3497 /* Similarly, if this is the _Controller field, put
3498 it before the other fields except for the _Tag or
3499 _Parent field. */
3501 {
3504 }
3506 /* Otherwise, if this is a regular field, put it after
3507 the other fields. */
3508 else
3509 {
3516 }
3519 }
3521 /* If there is a variant list, a selected variant and the fields
3522 all have a constant position, put them in order of increasing
3523 position to match that of constant CONSTRUCTORs. Likewise if
3524 there is no variant list but a REP part, since the latter has
3525 been flattened in the process. */
3529 {
3541 {
3544 }
3545 }
3547 /* If there is a variant list and no selected variant, we need
3548 to create the nest of variant parts from the old nest. */
3550 {
3551 tree new_variant_part
3557 }
3559 /* Now go through the entities again looking for Itypes that
3560 we have not elaborated but should (e.g., Etypes of fields
3561 that have Original_Components). */
3569 /* Do not emit debug info for the type yet since we're going to
3570 modify it below. */
3575 /* Fill in locations of fields. */
3578 /* If debugging information is being written for the type, write
3579 a record that shows what we are a subtype of and also make a
3580 variable that indicates our size, if still variable. */
3582 {
3584 tree gnu_unpad_base_name
3592 build_reference_type
3594 gnu_subtype_marker,
3609 gnat_entity);
3610 }
3615 /* Now we can finalize it. */
3617 }
3619 /* Otherwise, go down all the components in the new type and make
3620 them equivalent to those in the base type. */
3621 else
3622 {
3632 gnat_to_gnu_field_decl
3635 }
3636 }
3640 /* Use the special descriptor type for dispatch tables if needed,
3641 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3642 Note that we are only required to do so for static tables in
3643 order to be compatible with the C++ ABI, but Ada 2005 allows
3644 to extend library level tagged types at the local level so
3645 we do it in the non-static case as well. */
3648 {
3652 }
3654 /* ... fall through ... */
3657 /* If we are not defining this entity, and we have incomplete
3658 entities being processed above us, make a dummy type and
3659 fill it in later. */
3661 {
3664 gnu_type
3665 = build_pointer_type
3680 }
3682 /* ... fall through ... */
3689 {
3690 /* The designated type and its equivalent type for gigi. */
3693 /* Whether it comes from a limited with. */
3694 bool is_from_limited_with
3697 /* The "full view" of the designated type. If this is an incomplete
3698 entity from a limited with, treat its non-limited view as the full
3699 view. Otherwise, if this is an incomplete or private type, use the
3700 full view. In the former case, we might point to a private type,
3701 in which case, we need its full view. Also, we want to look at the
3702 actual type used for the representation, so this takes a total of
3703 three steps. */
3704 Entity_Id gnat_desig_full_direct_first
3705 = (is_from_limited_with
3709 Entity_Id gnat_desig_full_direct
3710 = ((is_from_limited_with
3715 Entity_Id gnat_desig_full
3717 /* The type actually used to represent the designated type, either
3718 gnat_desig_full or gnat_desig_equiv. */
3719 Entity_Id gnat_desig_rep;
3720 /* True if this is a pointer to an unconstrained array. */
3722 /* We want to know if we'll be seeing the freeze node for any
3723 incomplete type we may be pointing to. */
3724 bool in_main_unit
3728 /* True if we make a dummy type here. */
3730 /* The mode to be used for the pointer type. */
3732 /* The GCC type used for the designated type. */
3738 /* If either the designated type or its full view is an unconstrained
3739 array subtype, replace it with the type it's a subtype of. This
3740 avoids problems with multiple copies of unconstrained array types.
3741 Likewise, if the designated type is a subtype of an incomplete
3742 record type, use the parent type to avoid order of elaboration
3743 issues. This can lose some code efficiency, but there is no
3744 alternative. */
3755 /* Set the type that's actually the representation of the designated
3756 type and also flag whether we have a unconstrained array. */
3757 gnat_desig_rep
3759 is_unconstrained_array
3762 /* If we are pointing to an incomplete type whose completion is an
3763 unconstrained array, make dummy fat and thin pointer types to it.
3764 Likewise if the type itself is dummy or an unconstrained array. */
3768 && TYPE_IS_DUMMY_P
3770 || (!in_main_unit
3773 || (in_main_unit
3774 && is_from_limited_with
3776 {
3779 else
3780 {
3783 }
3785 /* If the call above got something that has a pointer, the pointer
3786 is our type. This could have happened either because the type
3787 was elaborated or because somebody else executed the code. */
3791 }
3793 /* If we already know what the full type is, use it. */
3798 /* Get the type of the thing we are to point to and build a pointer to
3799 it. If it is a reference to an incomplete or private type with a
3800 full view that is a record, make a dummy type node and get the
3801 actual type later when we have verified it is safe. */
3807 /* Likewise if we are pointing to a record or array and we are
3808 to defer elaborating incomplete types. We do this as this
3809 access type may be the full view of a private type. Note
3810 that the unconstrained array case is handled above. */
3816 /* If this is a reference from a limited_with type back to our
3817 main unit and there's a freeze node for it, either we have
3818 already processed the declaration and made the dummy type,
3819 in which case we just reuse the latter, or we have not yet,
3820 in which case we make the dummy type and it will be reused
3821 when the declaration is finally processed. In both cases,
3822 the pointer eventually created below will be automatically
3823 adjusted when the freeze node is processed. Note that the
3824 unconstrained array case is handled above. */
3825 || (in_main_unit
3826 && is_from_limited_with
3828 {
3831 }
3833 /* Otherwise handle the case of a pointer to itself. */
3835 {
3836 gnu_type
3840 }
3842 /* If expansion is disabled, the equivalent type of a concurrent type
3843 is absent, so build a dummy pointer type. */
3847 /* Finally, handle the default case where we can just elaborate our
3848 designated type. */
3849 else
3852 /* It is possible that a call to gnat_to_gnu_type above resolved our
3853 type. If so, just return it. */
3855 {
3858 }
3860 /* If we haven't done it yet, build the pointer type the usual way. */
3862 {
3863 /* Modify the designated type if we are pointing only to constant
3864 objects, but don't do it for unconstrained arrays. */
3867 {
3868 gnu_desig_type
3871 /* Some extra processing is required if we are building a
3872 pointer to an incomplete type (in the GCC sense). We might
3873 have such a type if we just made a dummy, or directly out
3874 of the call to gnat_to_gnu_type above if we are processing
3875 an access type for a record component designating the
3876 record type itself. */
3878 {
3879 /* We must ensure that the pointer to variant we make will
3880 be processed by update_pointer_to when the initial type
3881 is completed. Pretend we made a dummy and let further
3882 processing act as usual. */
3885 /* We must ensure that update_pointer_to will not retrieve
3886 the dummy variant when building a properly qualified
3887 version of the complete type. We take advantage of the
3888 fact that get_qualified_type is requiring TYPE_NAMEs to
3889 match to influence build_qualified_type and then also
3890 update_pointer_to here. */
3893 }
3894 }
3896 gnu_type
3899 }
3901 /* If we are not defining this object and we have made a dummy pointer,
3902 save our current definition, evaluate the actual type, and replace
3903 the tentative type we made with the actual one. If we are to defer
3904 actually looking up the actual type, make an entry in the deferred
3905 list. If this is from a limited with, we may have to defer to the
3906 end of the current unit. */
3908 {
3909 tree gnu_old_desig_type;
3912 {
3915 gnu_type = build_pointer_type
3917 }
3918 else
3930 /* Note that the call to gnat_to_gnu_type on gnat_desig_equiv might
3931 update gnu_old_desig_type directly, in which case it will not be
3932 a dummy type any more when we get into update_pointer_to.
3934 This can happen e.g. when the designated type is a record type,
3935 because their elaboration starts with an initial node from
3936 make_dummy_type, which may be the same node as the one we got.
3938 Besides, variants of this non-dummy type might have been created
3939 along the way. update_pointer_to is expected to properly take
3940 care of those situations. */
3942 {
3945 }
3946 else
3947 {
3950 = (is_from_limited_with
3956 }
3957 }
3958 }
3965 else
3966 {
3967 /* The run-time representation is the equivalent type. */
3970 }
3983 /* We treat this as identical to its base type; any constraint is
3984 meaningful only to the front-end.
3986 The designated type must be elaborated as well, if it does
3987 not have its own freeze node. Designated (sub)types created
3988 for constrained components of records with discriminants are
3989 not frozen by the front-end and thus not elaborated by gigi,
3990 because their use may appear before the base type is frozen,
3991 and because it is not clear that they are needed anywhere in
3992 gigi. With the current model, there is no correct place where
3993 they could be elaborated. */
4000 {
4001 /* If we are not defining this entity, and we have incomplete
4002 entities being processed above us, make a dummy type and
4003 elaborate it later. */
4005 {
4008 p->old_type
4013 }
4016 Incomplete_Or_Private_Kind))
4019 }
4024 /* Subprogram Entities
4026 The following access functions are defined for subprograms:
4028 Etype Return type or Standard_Void_Type.
4029 First_Formal The first formal parameter.
4030 Is_Imported Indicates that the subprogram has appeared in
4031 an INTERFACE or IMPORT pragma. For now we
4032 assume that the external language is C.
4033 Is_Exported Likewise but for an EXPORT pragma.
4034 Is_Inlined True if the subprogram is to be inlined.
4036 Each parameter is first checked by calling must_pass_by_ref on its
4037 type to determine if it is passed by reference. For parameters which
4038 are copied in, if they are Ada In Out or Out parameters, their return
4039 value becomes part of a record which becomes the return type of the
4040 function (C function - note that this applies only to Ada procedures
4041 so there is no Ada return type). Additional code to store back the
4042 parameters will be generated on the caller side. This transformation
4043 is done here, not in the front-end.
4045 The intended result of the transformation can be seen from the
4046 equivalent source rewritings that follow:
4048 struct temp {int a,b};
4049 procedure P (A,B: In Out ...) is temp P (int A,B)
4050 begin {
4051 .. ..
4052 end P; return {A,B};
4053 }
4055 temp t;
4056 P(X,Y); t = P(X,Y);
4057 X = t.a , Y = t.b;
4059 For subprogram types we need to perform mainly the same conversions to
4060 GCC form that are needed for procedures and function declarations. The
4061 only difference is that at the end, we make a type declaration instead
4062 of a function declaration. */
4067 {
4068 /* The type returned by a function or else Standard_Void_Type for a
4069 procedure. */
4071 tree gnu_return_type;
4072 /* The first GCC parameter declaration (a PARM_DECL node). The
4073 PARM_DECL nodes are chained through the DECL_CHAIN field, so this
4074 actually is the head of this parameter list. */
4076 /* Non-null for subprograms containing parameters passed by copy-in
4077 copy-out (Ada In Out or Out parameters not passed by reference),
4078 in which case it is the list of nodes used to specify the values
4079 of the In Out/Out parameters that are returned as a record upon
4080 procedure return. The TREE_PURPOSE of an element of this list is
4081 a field of the record and the TREE_VALUE is the PARM_DECL
4082 corresponding to that field. This list will be saved in the
4083 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
4085 /* List of fields in return type of procedure with copy-in copy-out
4086 parameters. */
4088 /* If an import pragma asks to map this subprogram to a GCC builtin,
4089 this is the builtin DECL node. */
4092 Entity_Id gnat_param;
4093 enum inline_status_t inline_status
4095 ? is_suppressed
4097 ? is_required
4100 /* Subprograms marked both Intrinsic and Always_Inline need not
4101 have a body of their own. */
4102 bool extern_flag
4104 || imported_p
4108 /* The semantics of "pure" in Ada essentially matches that of "const"
4109 in the back-end. In particular, both properties are orthogonal to
4110 the "nothrow" property if the EH circuitry is explicit in the
4111 internal representation of the back-end. If we are to completely
4112 hide the EH circuitry from it, we need to declare that calls to pure
4113 Ada subprograms that can throw have side effects since they can
4114 trigger an "abnormal" transfer of control flow; thus they can be
4115 neither "const" nor "pure" in the back-end sense. */
4116 bool const_flag
4125 /* A parameter may refer to this type, so defer completion of any
4126 incomplete types. */
4128 {
4129 defer_incomplete_level++;
4131 }
4133 /* If the subprogram has an alias, it is probably inherited, so
4134 we can use the original one. If the original "subprogram"
4135 is actually an enumeration literal, it may be the first use
4136 of its type, so we must elaborate that type now. */
4138 {
4144 /* Elaborate any Itypes in the parameters of this entity. */
4152 }
4154 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
4155 corresponding DECL node. Proper generation of calls later on need
4156 proper parameter associations so we don't "break;" here. */
4159 {
4162 /* Inability to find the builtin decl most often indicates a
4163 genuine mistake, but imports of unregistered intrinsics are
4164 sometimes issued on purpose to allow hooking in alternate
4165 bodies. We post a warning conditioned on Wshadow in this case,
4166 to let developers be notified on demand without risking false
4167 positives with common default sets of options. */
4171 }
4173 /* ??? What if we don't find the builtin node above ? warn ? err ?
4174 In the current state we neither warn nor err, and calls will just
4175 be handled as for regular subprograms. */
4177 /* Look into the return type and get its associated GCC tree. If it
4178 is not void, compute various flags for the subprogram type. */
4181 else
4182 {
4183 /* Ada 2012 (AI05-0151): Incomplete types coming from a limited
4184 context may now appear in parameter and result profiles. If
4185 we are only annotating types, break circularities here. */
4189 else
4192 /* If this function returns by reference, make the actual return
4193 type the pointer type and make a note of that. */
4195 {
4198 }
4200 /* If the return type is an unconstrained array type, the return
4201 value will be allocated on the secondary stack so the actual
4202 return type is the fat pointer type. */
4204 {
4207 }
4209 /* Likewise, if the return type requires a transient scope, the
4210 return value will also be allocated on the secondary stack so
4211 the actual return type is the pointer type. */
4213 {
4216 }
4218 /* If the Mechanism is By_Reference, ensure this function uses the
4219 target's by-invisible-reference mechanism, which may not be the
4220 same as above (e.g. it might be passing an extra parameter). */
4225 /* Likewise, if the return type is itself By_Reference. */
4229 /* If the type is a padded type and the underlying type would not
4230 be passed by reference or the function has a foreign convention,
4231 return the underlying type. */
4233 && (!default_pass_by_ref
4238 /* If the return type is unconstrained, that means it must have a
4239 maximum size. Use the padded type as the effective return type.
4240 And ensure the function uses the target's by-invisible-reference
4241 mechanism to avoid copying too much data when it returns. */
4243 {
4245 tree max_return_size
4248 /* If the size overflows to 0, set it to an arbitrary positive
4249 value so that assignments in the type are preserved. Their
4250 actual size is independent of this positive value. */
4254 {
4257 }
4259 gnu_return_type
4264 /* Declare it now since it will never be declared otherwise.
4265 This is necessary to ensure that its subtrees are properly
4266 marked. */
4271 gnat_entity);
4274 }
4276 /* If the return type has a size that overflows, we cannot have
4277 a function that returns that type. This usage doesn't make
4278 sense anyway, so give an error here. */
4283 {
4285 gnat_entity);
4291 }
4292 }
4294 /* Loop over the parameters and get their associated GCC tree. While
4295 doing this, build a copy-in copy-out structure if we need one. */
4299 {
4306 /* Ada 2012 (AI05-0151): Incomplete types coming from a limited
4307 context may now appear in parameter and result profiles. If
4308 we are only annotating types, break circularities here. */
4311 {
4314 }
4315 else
4316 {
4319 }
4321 /* Builtins are expanded inline and there is no real call sequence
4322 involved. So the type expected by the underlying expander is
4323 always the type of each argument "as is". */
4326 /* Handle the first parameter of a valued procedure specially. */
4329 /* Otherwise, see if a Mechanism was supplied that forced this
4330 parameter to be passed one way or another. */
4334 ;
4336 {
4340 mech))
4342 else
4344 }
4345 else
4346 {
4349 }
4351 /* Do not call gnat_to_gnu_param for a fake parameter type since
4352 it will try to use the real type again. */
4354 {
4357 else
4358 {
4359 gnu_param
4366 }
4367 }
4368 else
4369 gnu_param
4374 /* We are returned either a PARM_DECL or a type if no parameter
4375 needs to be passed; in either case, adjust the type. */
4378 else
4379 {
4382 }
4384 /* The failure of this assertion will very likely come from an
4385 order of elaboration issue for the type of the parameter. */
4391 {
4397 /* If a parameter is a pointer, this function may modify
4398 memory through it and thus shouldn't be considered
4399 a const function. Also, the memory may be modified
4400 between two calls, so they can't be CSE'ed. The latter
4401 case also handles by-ref parameters. */
4405 }
4408 {
4410 {
4413 /* If this is a function, we also need a field for the
4414 return value to be placed. */
4416 {
4417 gnu_field
4419 gnu_return_type,
4425 gnu_cico_list
4427 }
4431 /* Set a default alignment to speed up accesses. But we
4432 shouldn't increase the size of the structure too much,
4433 lest it doesn't fit in return registers anymore. */
4436 }
4438 gnu_field
4446 gnu_cico_list
4448 }
4449 }
4452 {
4453 /* If we have a CICO list but it has only one entry, we convert
4454 this function into a function that returns this object. */
4458 /* Do not finalize the return type if the subprogram is stubbed
4459 since structures are incomplete for the back-end. */
4461 {
4465 /* Try to promote the mode of the return type if it is passed
4466 in registers, again to speed up accesses. */
4469 NULL_TREE))
4470 {
4471 unsigned int size
4474 machine_mode mode;
4480 {
4488 }
4489 }
4493 }
4494 }
4496 /* Deal with platform-specific calling conventions. */
4498 prepend_one_attribute
4501 gnat_entity);
4503 prepend_one_attribute
4506 gnat_entity);
4508 /* If we should request stack realignment for a foreign convention
4509 subprogram, do so. Note that this applies to task entry points
4510 in particular. */
4513 prepend_one_attribute
4516 gnat_entity);
4518 /* Deal with a pragma Linker_Section on a subprogram. */
4524 /* The lists have been built in reverse. */
4530 || return_by_direct_ref_p
4531 || return_by_invisi_ref_p
4533 gnu_type
4536 return_by_direct_ref_p,
4537 return_by_invisi_ref_p);
4539 /* A procedure (something that doesn't return anything) shouldn't be
4540 considered const since there would be no reason for calling such a
4541 subprogram. Note that procedures with Out (or In Out) parameters
4542 have already been converted into a function with a return type.
4543 Similarly, if the function returns an unconstrained type, then the
4544 function will allocate the return value on the secondary stack and
4545 thus calls to it cannot be CSE'ed, lest the stack be reclaimed. */
4550 {
4551 const int quals
4555 }
4557 /* If we have a builtin decl for that function, use it. Check if the
4558 profiles are compatible and warn if they are not. The checker is
4559 expected to post extra diagnostics in this case. */
4561 {
4562 intrin_binding_t inb;
4569 post_error
4571 gnat_entity);
4576 }
4578 /* If there was no specified Interface_Name and the external and
4579 internal names of the subprogram are the same, only use the
4580 internal name to allow disambiguation of nested subprograms. */
4585 /* If we are defining the subprogram and it has an Address clause
4586 we must get the address expression from the saved GCC tree for the
4587 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4588 the address expression here since the front-end has guaranteed
4589 in that case that the elaboration has no effects. If there is
4590 an Address clause and we are not defining the object, just
4591 make it a constant. */
4593 {
4597 gnu_address
4604 /* Convert the type of the object to a reference type that can
4605 alias everything as per 13.3(19). */
4606 gnu_type
4611 gnu_decl
4616 }
4619 {
4621 gnu_decl
4624 }
4625 else
4626 {
4627 gnu_decl
4632 /* This is unrelated to the stub built right above. */
4635 }
4636 }
4647 {
4648 bool is_from_limited_with
4650 /* Get the "full view" of this entity. If this is an incomplete
4651 entity from a limited with, treat its non-limited view as the
4652 full view. Otherwise, use either the full view or the underlying
4653 full view, whichever is present. This is used in all the tests
4654 below. */
4655 Entity_Id full_view
4656 = is_from_limited_with
4664 /* If this is an incomplete type with no full view, it must be a Taft
4665 Amendment type, in which case we return a dummy type. Otherwise,
4666 just get the type from its Etype. */
4668 {
4670 {
4673 }
4674 else
4675 {
4679 }
4681 }
4683 /* If we already made a type for the full view, reuse it. */
4685 {
4688 }
4690 /* Otherwise, if we are not defining the type now, get the type
4691 from the full view. But always get the type from the full view
4692 for define on use types, since otherwise we won't see them.
4693 Likewise if this is a non-limited view not declared in the main
4694 unit, which can happen for incomplete formal types instantiated
4695 on a type coming from a limited_with clause. */
4699 || (is_from_limited_with
4701 {
4705 }
4707 /* For incomplete types, make a dummy type entry which will be
4708 replaced later. Save it as the full declaration's type so
4709 we can do any needed updates when we see it. */
4716 }
4719 /* Class-wide types are always transformed into their root type. */
4728 /* Concurrent types are always transformed into their record type. */
4731 else
4742 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4743 we've already saved it, so we don't try to. */
4749 /* This is a SPARK annotation that only reaches here when compiling in
4750 ASIS mode. */
4758 }
4760 /* If we had a case where we evaluated another type and it might have
4761 defined this one, handle it here. */
4763 {
4766 }
4768 /* If we are processing a type and there is either no decl for it or
4769 we just made one, do some common processing for the type, such as
4770 handling alignment and possible padding. */
4772 {
4773 /* Process the attributes, if not already done. Note that the type is
4774 already defined so we cannot pass true for IN_PLACE here. */
4777 /* Tell the middle-end that objects of tagged types are guaranteed to
4778 be properly aligned. This is necessary because conversions to the
4779 class-wide type are translated into conversions to the root type,
4780 which can be less aligned than some of its derived types. */
4785 /* Record whether the type is passed by reference. */
4789 /* ??? Don't set the size for a String_Literal since it is either
4790 confirming or we don't handle it properly (if the low bound is
4791 non-constant). */
4793 {
4796 gnu_size
4799 }
4801 /* If a size was specified, see if we can make a new type of that size
4802 by rearranging the type, for example from a fat to a thin pointer. */
4804 {
4805 gnu_type
4812 }
4814 /* If the alignment has not already been processed and this is not
4815 an unconstrained array type, see if an alignment is specified.
4816 If not, we pick a default alignment for atomic objects. */
4818 ;
4820 {
4824 /* Warn on suspiciously large alignments. This should catch
4825 errors about the (alignment,byte)/(size,bit) discrepancy. */
4827 {
4828 tree size;
4830 /* If a size was specified, take it into account. Otherwise
4831 use the RM size for records or unions as the type size has
4832 already been adjusted to the alignment. */
4838 else
4841 /* Consider an alignment as suspicious if the alignment/size
4842 ratio is greater or equal to the byte/bit ratio. */
4847 gnat_entity);
4848 }
4849 }
4860 /* See if we need to pad the type. If we did, and made a record,
4861 the name of the new type may be changed. So get it back for
4862 us when we make the new TYPE_DECL below. */
4870 /* Now set the RM size of the type. We cannot do it before padding
4871 because we need to accept arbitrary RM sizes on integral types. */
4874 /* If we are at global level, GCC will have applied variable_size to
4875 the type, but that won't have done anything. So, if it's not
4876 a constant or self-referential, call elaborate_expression_1 to
4877 make a variable for the size rather than calculating it each time.
4878 Handle both the RM size and the actual size. */
4883 {
4890 /* ??? For now, store the size as a multiple of the alignment in
4891 bytes so that we can see the alignment from the tree. */
4897 /* ??? gnu_type may come from an existing type so the MULT_EXPR node
4898 may not be marked by the call to create_type_decl below. */
4902 {
4907 {
4911 /* If the position of the variant part is constant, subtract
4912 it from the size of the type of the parent to get the new
4913 size. This manual CSE reduces the data size. */
4915 {
4923 }
4924 else
4925 {
4931 /* ??? For now, store the size as a multiple of the
4932 alignment in bytes so that we can see the alignment
4933 from the tree. */
4940 /* ??? For now, store the offset as a multiple of the
4941 alignment in bytes so that we can see the alignment
4942 from the tree. */
4946 DECL_OFFSET_ALIGN
4948 }
4952 }
4956 else
4957 ada_size
4961 }
4962 }
4964 /* If this is a record type or subtype, call elaborate_expression_2 on
4965 any field position. Do this for both global and local types.
4966 Skip any fields that we haven't made trees for to avoid problems with
4967 class wide types. */
4972 {
4975 /* ??? For now, store the offset as a multiple of the alignment
4976 in bytes so that we can see the alignment from the tree. */
4978 {
4985 /* ??? The context of gnu_field is not necessarily gnu_type
4986 so the MULT_EXPR node built above may not be marked by
4987 the call to create_type_decl below. */
4990 }
4991 }
4996 /* If this is not an unconstrained array type, set some flags. */
4998 {
5005 /* If it is passed by reference, force BLKmode to ensure that
5006 objects of this type will always be put in memory. */
5013 {
5014 const int quals
5015 = TYPE_QUAL_VOLATILE
5018 }
5019 }
5025 else
5026 {
5029 }
5030 }
5033 {
5036 /* If this is a derived type, relate its alias set to that of its parent
5037 to avoid troubles when a call to an inherited primitive is inlined in
5038 a context where a derived object is accessed. The inlined code works
5039 on the parent view so the resulting code may access the same object
5040 using both the parent and the derived alias sets, which thus have to
5041 conflict. As the same issue arises with component references, the
5042 parent alias set also has to conflict with composite types enclosing
5043 derived components. For instance, if we have:
5045 type D is new T;
5046 type R is record
5047 Component : D;
5048 end record;
5050 we want T to conflict with both D and R, in addition to R being a
5051 superset of D by record/component construction.
5053 One way to achieve this is to perform an alias set copy from the
5054 parent to the derived type. This is not quite appropriate, though,
5055 as we don't want separate derived types to conflict with each other:
5057 type I1 is new Integer;
5058 type I2 is new Integer;
5060 We want I1 and I2 to both conflict with Integer but we do not want
5061 I1 to conflict with I2, and an alias set copy on derivation would
5062 have that effect.
5064 The option chosen is to make the alias set of the derived type a
5065 superset of that of its parent type. It trivially fulfills the
5066 simple requirement for the Integer derivation example above, and
5067 the component case as well by superset transitivity:
5069 superset superset
5070 R ----------> D ----------> T
5072 However, for composite types, conversions between derived types are
5073 translated into VIEW_CONVERT_EXPRs so a sequence like:
5075 type Comp1 is new Comp;
5076 type Comp2 is new Comp;
5077 procedure Proc (C : Comp1);
5079 C : Comp2;
5080 Proc (Comp1 (C));
5082 is translated into:
5084 C : Comp2;
5085 Proc ((Comp1 &) &VIEW_CONVERT_EXPR <Comp1> (C));
5087 and gimplified into:
5089 C : Comp2;
5090 Comp1 *C.0;
5091 C.0 = (Comp1 *) &C;
5092 Proc (C.0);
5094 i.e. generates code involving type punning. Therefore, Comp1 needs
5095 to conflict with Comp2 and an alias set copy is required.
5097 The language rules ensure the parent type is already frozen here. */
5101 {
5103 /* For constrained packed array subtypes, the implementation type is
5104 used instead of the nominal type. */
5112 }
5114 /* Back-annotate the Alignment of the type if not already in the
5115 tree. Likewise for sizes. */
5117 {
5121 /* If the default alignment of "double" or larger scalar types is
5122 specifically capped and this is not an array with an alignment
5123 clause on the component type, return the cap. */
5125 is_capped_double
5128 is_capped_double
5130 else
5135 else
5139 }
5142 {
5145 /* If the size is self-referential, annotate the maximum value. */
5149 /* If we are just annotating types and the type is tagged, the tag
5150 and the parent components are not generated by the front-end so
5151 sizes must be adjusted if there is no representation clause. */
5157 {
5159 Uint uint_size;
5162 {
5166 }
5167 else
5171 offset
5179 }
5180 else
5182 }
5186 }
5188 /* If we really have a ..._DECL node, set a couple of flags on it. But we
5189 cannot do so if we are reusing the ..._DECL node made for an equivalent
5190 type or an alias or a renamed object as the predicates don't apply to it
5191 but to GNAT_ENTITY. */
5196 {
5197 /* ??? DECL_ARTIFICIAL, and possibly DECL_IGNORED_P below, should
5198 be set before calling rest_of_decl_compilation above (through
5199 create_var_decl_1). This is because rest_of_decl_compilation
5200 calls the debugging backend and will create a DIE without
5201 DW_AT_artificial.
5203 This is currently causing gnat.dg/specs/debug1.ads to FAIL. */
5209 }
5211 /* If we haven't already, associate the ..._DECL node that we just made with
5212 the input GNAT entity node. */
5216 /* Now we are sure gnat_entity has a corresponding ..._DECL node,
5217 eliminate as many deferred computations as possible. */
5220 /* If this is an enumeration or floating-point type, we were not able to set
5221 the bounds since they refer to the type. These are always static. */
5224 {
5228 /* If this is a padded type, we need to use the underlying type. */
5232 /* If this is a floating point type and we haven't set a floating
5233 point type yet, use this in the evaluation of the bounds. */
5241 {
5242 /* Enumeration types have specific RM bounds. */
5245 }
5246 else
5247 {
5248 /* Floating-point types don't have specific RM bounds. */
5251 }
5252 }
5254 /* If we deferred processing of incomplete types, re-enable it. If there
5255 were no other disables and we have deferred types to process, do so. */
5259 {
5262 /* We are back to level 0 for the deferring of incomplete types.
5263 But processing these incomplete types below may itself require
5264 deferring, so preserve what we have and restart from scratch. */
5269 {
5276 }
5277 }
5279 /* If we are not defining this type, see if it's on one of the lists of
5280 incomplete types. If so, handle the list entry now. */
5282 {
5287 {
5291 }
5295 {
5299 }
5300 }
5303 force_global--;
5305 /* If this is a packed array type whose original array type is itself
5306 an Itype without freeze node, make sure the latter is processed. */
5314 }
5316 /* Similar, but if the returned value is a COMPONENT_REF, return the
5317 FIELD_DECL. */
5319 tree
5321 {
5328 }
5330 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5331 the GCC type corresponding to that entity. */
5333 tree
5335 {
5336 tree gnu_decl;
5338 /* The back end never attempts to annotate generic types. */
5346 }
5348 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5349 the unpadded version of the GCC type corresponding to that entity. */
5351 tree
5353 {
5360 }
5362 /* Return the DECL associated with the public subprogram GNAT_ENTITY but whose
5363 type has been changed to that of the parameterless procedure, except if an
5364 alias is already present, in which case it is returned instead. */
5366 tree
5368 {
5372 /* See the E_Function/E_Procedure case of gnat_to_gnu_entity for the model
5373 of the handling applied here. */
5376 {
5380 }
5388 gnat_entity);
5392 gnat_entity);
5397 return
5400 }
5402 /* Return whether the E_Subprogram_Type/E_Function/E_Procedure GNAT_ENTITY is
5403 a C++ imported method or equivalent.
5405 We use the predicate on 32-bit x86/Windows to find out whether we need to
5406 use the "thiscall" calling convention for GNAT_ENTITY. This convention is
5407 used for C++ methods (functions with METHOD_TYPE) by the back-end. */
5409 bool
5411 {
5415 /* This is the main case: C++ method imported as a primitive operation.
5416 Note that a C++ class with no virtual functions can be imported as a
5417 limited record type so the operation is not necessarily dispatching. */
5421 /* A thunk needs to be handled like its associated primitive operation. */
5425 /* A constructor is a method on the C++ side. */
5429 /* This is set on the E_Subprogram_Type built for a dispatching call. */
5434 }
5436 /* Finalize the processing of From_Limited_With incomplete types. */
5438 void
5440 {
5447 {
5454 }
5455 }
5457 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
5458 kind of type (such E_Task_Type) that has a different type which Gigi
5459 uses for its representation. If the type does not have a special type
5460 for its representation, return GNAT_ENTITY. If a type is supposed to
5461 exist, but does not, abort unless annotating types, in which case
5462 return Empty. If GNAT_ENTITY is Empty, return Empty. */
5464 Entity_Id
5466 {
5473 {
5497 }
5502 }
5504 /* Return a GCC tree for a type corresponding to the component type of the
5505 array type or subtype GNAT_ARRAY. DEFINITION is true if this component
5506 is for an array being defined. DEBUG_INFO_P is true if we need to write
5507 debug information for other types that we may create in the process. */
5509 static tree
5512 {
5515 tree gnu_comp_size;
5517 /* Try to get a smaller form of the component if needed. */
5531 /* Get and validate any specified Component_Size. */
5532 gnu_comp_size
5537 /* If the array has aliased components and the component size can be zero,
5538 force at least unit size to ensure that the components have distinct
5539 addresses. */
5545 gnu_comp_size
5548 /* If the component type is a RECORD_TYPE that has a self-referential size,
5549 then use the maximum size for the component size. */
5555 /* Honor the component size. This is not needed for bit-packed arrays. */
5557 {
5561 /* If an alignment is specified, use it as a cap on the component type
5562 so that it can be honored for the whole type. But ignore it for the
5563 original type of packed array types. */
5567 else
5573 else
5579 /* If a padding record was made, declare it now since it will never be
5580 declared otherwise. This is necessary to ensure that its subtrees
5581 are properly marked. */
5584 gnat_array);
5585 }
5588 {
5589 const int quals
5590 = TYPE_QUAL_VOLATILE
5593 }
5596 }
5598 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
5599 using MECH as its passing mechanism, to be placed in the parameter
5600 list built for GNAT_SUBPROG. Assume a foreign convention for the
5601 latter if FOREIGN is true. Also set CICO to true if the parameter
5602 must use the copy-in copy-out implementation mechanism.
5604 The returned tree is a PARM_DECL, except for those cases where no
5605 parameter needs to be actually passed to the subprogram; the type
5606 of this "shadow" parameter is then returned instead. */
5608 static tree
5611 {
5615 /* The parameter can be indirectly modified if its address is taken. */
5619 tree gnu_param;
5621 /* Copy-return is used only for the first parameter of a valued procedure.
5622 It's a copy mechanism for which a parameter is never allocated. */
5624 {
5628 }
5630 /* If this is either a foreign function or if the underlying type won't
5631 be passed by reference and is as aligned as the original type, strip
5632 off possible padding type. */
5634 {
5643 }
5645 /* If this is a read-only parameter, make a variant of the type that is
5646 read-only. ??? However, if this is an unconstrained array, that type
5647 can be very complex, so skip it for now. Likewise for any other
5648 self-referential type. */
5654 /* For foreign conventions, pass arrays as pointers to the element type.
5655 First check for unconstrained array and get the underlying array. */
5657 gnu_param_type
5660 /* For GCC builtins, pass Address integer types as (void *) */
5666 /* Arrays are passed as pointers to element type for foreign conventions. */
5668 {
5669 /* Strip off any multi-dimensional entries, then strip
5670 off the last array to get the component type. */
5679 gnu_param_type
5683 }
5685 /* Fat pointers are passed as thin pointers for foreign conventions. */
5687 gnu_param_type
5690 /* If we must pass or were requested to pass by reference, do so.
5691 If we were requested to pass by copy, do so.
5692 Otherwise, for foreign conventions, pass In Out or Out parameters
5693 or aggregates by reference. For COBOL and Fortran, pass all
5694 integer and FP types that way too. For Convention Ada, use
5695 the standard Ada default. */
5699 && ((foreign
5701 || (foreign
5706 || (!foreign
5708 {
5709 /* We take advantage of 6.2(12) by considering that references built for
5710 parameters whose type isn't by-ref and for which the mechanism hasn't
5711 been forced to by-ref are restrict-qualified in the C sense. */
5712 bool restrict_p
5716 gnu_param_type
5719 }
5721 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
5728 /* If this is an Out parameter that isn't passed by reference and isn't
5729 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
5730 it will be a VAR_DECL created when we process the procedure, so just
5731 return its type. For the special parameter of a valued procedure,
5732 never pass it in.
5734 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
5735 Out parameters with discriminants or implicit initial values to be
5736 handled like In Out parameters. These type are normally built as
5737 aggregates, hence passed by reference, except for some packed arrays
5738 which end up encoded in special integer types. Note that scalars can
5739 be given implicit initial values using the Default_Value aspect.
5741 The exception we need to make is then for packed arrays of records
5742 with discriminants or implicit initial values. We have no light/easy
5743 way to check for the latter case, so we merely check for packed arrays
5744 of records. This may lead to useless copy-in operations, but in very
5745 rare cases only, as these would be exceptions in a set of already
5746 exceptional situations. */
5748 && !by_ref
5749 && (by_return
5766 /* If no Mechanism was specified, indicate what we're using, then
5767 back-annotate it. */
5773 }
5775 /* Return true if GNAT_ENTITY is an incomplete entity coming from a limited
5776 with of the main unit and whose full view has not been elaborated yet. */
5778 static bool
5780 {
5781 /* Class-wide types are always transformed into their root type. */
5787 {
5794 }
5797 }
5799 /* Like build_qualified_type, but TYPE_QUALS is added to the existing
5800 qualifiers on TYPE. */
5802 static tree
5804 {
5806 }
5808 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
5810 static bool
5812 {
5819 return
5821 }
5823 /* Return true if the array type GNU_TYPE, which represents a dimension of
5824 GNAT_TYPE, has a non-aliased component in the back-end sense. */
5826 static bool
5828 {
5829 /* If the array type is not the innermost dimension of the GNAT type,
5830 then it has a non-aliased component. */
5835 /* If the array type has an aliased component in the front-end sense,
5836 then it also has an aliased component in the back-end sense. */
5840 /* If this is a derived type, then it has a non-aliased component if
5841 and only if its parent type also has one. */
5843 {
5847 gnu_parent_type
5852 }
5854 /* Otherwise, rely exclusively on properties of the element type. */
5856 }
5858 /* Return true if GNAT_ADDRESS is a value known at compile-time. */
5860 static bool
5862 {
5863 /* Catch System'To_Address. */
5868 }
5870 /* Return true if GNAT_RANGE, a N_Range node, cannot be superflat, i.e. if the
5871 inequality HB >= LB-1 is true. LB and HB are the low and high bounds. */
5873 static bool
5875 {
5877 Node_Id scalar_range;
5880 /* If the low bound is not constant, try to find an upper bound. */
5889 /* If the high bound is not constant, try to find a lower bound. */
5898 /* If we have failed to find constant bounds, punt. */
5903 /* We need at least a signed 64-bit type to catch most cases. */
5909 /* If the low bound is the smallest integer, nothing can be smaller. */
5915 }
5917 /* Return true if GNU_EXPR is (essentially) the address of a CONSTRUCTOR. */
5919 static bool
5921 {
5929 }
5931 /* Return true if the size in units represented by GNU_SIZE can be handled by
5932 an allocation. If STATIC_P is true, consider only what can be done with a
5933 static allocation. */
5935 static bool
5937 {
5938 /* We can allocate a fixed size if it is a valid for the middle-end. */
5942 /* We can allocate a variable size if this isn't a static allocation. */
5943 else
5945 }
5947 /* Return true if GNU_EXPR needs a conversion to GNU_TYPE when used as the
5948 initial value of an object of GNU_TYPE. */
5950 static bool
5952 {
5953 /* Do not convert if the object's type is unconstrained because this would
5954 generate useless evaluations of the CONSTRUCTOR to compute the size. */
5959 /* Do not convert if the object's type is a padding record whose field is of
5960 self-referential size because we want to copy only the actual data. */
5964 /* Do not convert a call to a function that returns with variable size since
5965 we want to use the return slot optimization in this case. */
5970 /* Do not convert to a record type with a variant part from a record type
5971 without one, to keep the object simpler. */
5978 /* In all the other cases, convert the expression to the object's type. */
5980 }
5981 \f
5982 /* Given GNAT_ENTITY, elaborate all expressions that are required to
5983 be elaborated at the point of its definition, but do nothing else. */
5985 void
5987 {
5989 {
5996 {
6000 /* ??? Tests to avoid Constraint_Error in static expressions
6001 are needed until after the front stops generating bogus
6002 conversions on bounds of real types. */
6010 }
6017 {
6018 Node_Id gnat_discriminant_expr;
6019 Entity_Id gnat_field;
6023 gnat_discriminant_expr
6028 /* Ignore access discriminants. */
6033 }
6036 }
6037 }
6038 \f
6039 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
6040 NAME, ARGS and ERROR_POINT. */
6042 static void
6045 tree attr_name,
6046 tree attr_args,
6047 Node_Id attr_error_point)
6048 {
6058 }
6060 /* Prepend to ATTR_LIST an entry for an attribute provided by GNAT_PRAGMA. */
6062 static void
6064 {
6069 /* Map the pragma at hand. Skip if this isn't one we know how to handle. */
6071 {
6102 }
6104 /* See what arguments we have and turn them into GCC trees for attribute
6105 handlers. These expect identifier for strings. We handle at most two
6106 arguments and static expressions only. */
6108 {
6114 {
6118 {
6122 }
6125 }
6129 {
6134 }
6135 }
6137 /* Prepend to the list. Make a list of the argument we might have, as GCC
6138 expects it. */
6140 gnu_arg1
6144 }
6146 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
6148 static void
6150 {
6151 Node_Id gnat_temp;
6153 /* Attributes are stored as Representation Item pragmas. */
6159 }
6160 \f
6161 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
6162 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
6163 return the GCC tree to use for that expression. S is the suffix to use
6164 if a variable needs to be created and DEFINITION is true if this is done
6165 for a definition of GNAT_ENTITY. If NEED_VALUE is true, we need a result;
6166 otherwise, we are just elaborating the expression for side-effects. If
6167 NEED_DEBUG is true, we need a variable for debugging purposes even if it
6168 isn't needed for code generation. */
6170 static tree
6173 {
6174 tree gnu_expr;
6176 /* If we already elaborated this expression (e.g. it was involved
6177 in the definition of a private type), use the old value. */
6181 /* If we don't need a value and this is static or a discriminant,
6182 we don't need to do anything. */
6189 /* If it's a static expression, we don't need a variable for debugging. */
6193 /* Otherwise, convert this tree to its GCC equivalent and elaborate it. */
6197 /* Save the expression in case we try to elaborate this entity again. Since
6198 it's not a DECL, don't check it. Don't save if it's a discriminant. */
6203 }
6205 /* Similar, but take a GNU expression and always return a result. */
6207 static tree
6210 {
6215 /* If GNU_EXPR contains a placeholder, just return it. We rely on the fact
6216 that an expression cannot contain both a discriminant and a variable. */
6220 /* If GNU_EXPR is neither a constant nor based on a read-only variable, make
6221 a variable that is initialized to contain the expression when the package
6222 containing the definition is elaborated. If this entity is defined at top
6223 level, replace the expression by the variable; otherwise use a SAVE_EXPR
6224 if this is necessary. */
6227 else
6228 {
6229 /* Skip any conversions and simple constant arithmetics to see if the
6230 expression is based on a read-only variable. */
6238 expr_variable_p
6239 = !(inner
6242 }
6244 /* We only need to use the variable if we are in a global context since GCC
6245 can do the right thing in the local case. However, when not optimizing,
6246 use it for bounds of loop iteration scheme to avoid code duplication. */
6247 use_variable = expr_variable_p
6248 && (expr_global_p
6249 || (!optimize
6250 && definition
6255 /* Now create it, possibly only for debugging purposes. */
6257 {
6258 /* The following variable creation can happen when processing the body
6259 of subprograms that are defined out of the extended main unit and
6260 inlined. In this case, we are not at the global scope, and thus the
6261 new variable must not be tagged "external", as we used to do here as
6262 soon as DEFINITION was false. */
6263 tree gnu_decl
6269 /* Whether or not gnat_entity comes from source, this variable is a
6270 compilation artifact. */
6273 /* Using this variable at debug time (if need_debug is true) requires a
6274 proper location. The back-end will compute a location for this
6275 variable only if the variable is used by the generated code.
6276 Returning the variable ensures the caller will use it in generated
6277 code. Note that there is no need for a location if the debug info
6278 contains an integer constant.
6279 FIXME: when the encoding-based debug scheme is dropped, move this
6280 condition to the top-level IF block: we will not need to create a
6281 variable anymore in such cases, then. */
6284 }
6287 }
6289 /* Similar, but take an alignment factor and make it explicit in the tree. */
6291 static tree
6294 {
6296 return
6299 gnu_expr,
6300 unit_align),
6302 need_debug),
6303 unit_align);
6304 }
6306 /* Structure to hold internal data for elaborate_reference. */
6308 struct er_data
6309 {
6310 Entity_Id entity;
6313 };
6315 /* Wrapper function around elaborate_expression_1 for elaborate_reference. */
6317 static tree
6319 {
6323 /* This is what elaborate_expression_1 does if NEED_DEBUG is false. */
6327 /* If this is a COMPONENT_REF of a fat pointer, elaborate the entire fat
6328 pointer. This may be more efficient, but will also allow us to more
6329 easily find the match for the PLACEHOLDER_EXPR. */
6337 return
6339 }
6341 /* Elaborate the reference REF to be used as renamed object for GNAT_ENTITY.
6342 DEFINITION is true if this is done for a definition of GNAT_ENTITY and
6343 INIT is set to the first arm of a COMPOUND_EXPR present in REF, if any. */
6345 static tree
6348 {
6351 }
6352 \f
6353 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
6354 the value passed against the list of choices. */
6356 tree
6358 {
6359 Node_Id choice;
6360 Node_Id gnat_temp;
6365 {
6367 {
6372 this_test
6386 this_test
6396 /* This represents either a subtype range, an enumeration
6397 literal, or a constant Ekind says which. If an enumeration
6398 literal or constant, fall through to the next case. */
6401 {
6407 this_test
6414 }
6416 /* ... fall through ... */
6422 single);
6431 }
6434 this_test);
6435 }
6438 }
6439 \f
6440 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
6441 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
6443 static int
6445 {
6446 /* If the field contains an item of variable size, we cannot pack it
6447 because we cannot create temporaries of non-fixed size in case
6448 we need to take the address of the field. See addressable_p and
6449 the notes on the addressability issues for further details. */
6453 /* If the alignment of the record is specified and the field type
6454 is over-aligned, request Storage_Unit alignment for the field. */
6456 {
6459 else
6461 }
6464 }
6466 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
6467 placed in GNU_RECORD_TYPE.
6469 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
6470 record has Component_Alignment of Storage_Unit, -2 if the enclosing
6471 record has a specified alignment.
6473 DEFINITION is true if this field is for a record being defined.
6475 DEBUG_INFO_P is true if we need to write debug information for types
6476 that we may create in the process. */
6478 static tree
6481 {
6483 const bool is_aliased
6485 const bool is_atomic
6487 const bool is_independent
6489 const bool is_volatile
6491 const bool needs_strict_alignment
6492 = (is_aliased
6493 || is_independent
6494 || is_volatile
6500 /* If this field requires strict alignment, we cannot pack it because
6501 it would very likely be under-aligned in the record. */
6504 else
6507 /* If a size is specified, use it. Otherwise, if the record type is packed,
6508 use the official RM size. See "Handling of Type'Size Values" in Einfo
6509 for further details. */
6516 else
6519 /* If we have a specified size that is smaller than that of the field's type,
6520 or a position is specified, and the field's type is a record that doesn't
6521 require strict alignment, see if we can get either an integral mode form
6522 of the type or a smaller form. If we can, show a size was specified for
6523 the field if there wasn't one already, so we know to make this a bitfield
6524 and avoid making things wider.
6526 Changing to an integral mode form is useful when the record is packed as
6527 we can then place the field at a non-byte-aligned position and so achieve
6528 tighter packing. This is in addition required if the field shares a byte
6529 with another field and the front-end lets the back-end handle the access
6530 to the field, because GCC cannot handle non-byte-aligned BLKmode fields.
6532 Changing to a smaller form is required if the specified size is smaller
6533 than that of the field's type and the type contains sub-fields that are
6534 padded, in order to avoid generating accesses to these sub-fields that
6535 are wider than the field.
6537 We avoid the transformation if it is not required or potentially useful,
6538 as it might entail an increase of the field's alignment and have ripple
6539 effects on the outer record type. A typical case is a field known to be
6540 byte-aligned and not to share a byte with another field. */
6546 || (gnu_size
6552 {
6555 {
6559 }
6560 }
6566 {
6568 Entity_Id gnat_parent
6575 /* Ensure the position does not overlap with the parent subtype, if there
6576 is one. This test is omitted if the parent of the tagged type has a
6577 full rep clause since, in this case, component clauses are allowed to
6578 overlay the space allocated for the parent type and the front-end has
6579 checked that there are no overlapping components. */
6581 {
6586 post_error_ne_tree
6589 }
6591 /* If this field needs strict alignment, make sure that the record is
6592 sufficiently aligned and that the position and size are consistent
6593 with the type. But don't do it if we are just annotating types and
6594 the field's type is tagged, since tagged types aren't fully laid out
6595 in this mode. Also, note that atomic implies volatile so the inner
6596 test sequences ordering is significant here. */
6599 {
6605 /* If the position is not a multiple of the alignment of the type,
6606 then error out and reset the position. */
6609 {
6623 else
6627 type_align);
6629 }
6632 {
6636 /* If the size is lower than that of the type, or greater for
6637 atomic and aliased, then error out and reset the size. */
6639 {
6653 else
6657 gnu_type_size);
6659 }
6661 /* Likewise if the size is not a multiple of a byte, */
6663 bitsize_unit_node)))
6664 {
6676 else
6681 }
6682 }
6683 }
6684 }
6686 /* If the record has rep clauses and this is the tag field, make a rep
6687 clause for it as well. */
6690 {
6693 }
6695 else
6696 {
6699 /* If we are packing the record and the field is BLKmode, round the
6700 size up to a byte boundary. */
6703 }
6705 /* We need to make the size the maximum for the type if it is
6706 self-referential and an unconstrained type. In that case, we can't
6707 pack the field since we can't make a copy to align it. */
6709 && !gnu_size
6712 {
6715 }
6717 /* If a size is specified, adjust the field's type to it. */
6719 {
6720 tree orig_field_type;
6722 /* If the field's type is justified modular, we would need to remove
6723 the wrapper to (better) meet the layout requirements. However we
6724 can do so only if the field is not aliased to preserve the unique
6725 layout and if the prescribed size is not greater than that of the
6726 packed array to preserve the justification. */
6734 /* Similarly if the field's type is a misaligned integral type, but
6735 there is no restriction on the size as there is no justification. */
6741 gnu_field_type
6749 /* If a padding record was made, declare it now since it will never be
6750 declared otherwise. This is necessary to ensure that its subtrees
6751 are properly marked. */
6756 }
6758 /* Otherwise (or if there was an error), don't specify a position. */
6759 else
6765 /* Now create the decl for the field. */
6766 gnu_field
6778 }
6779 \f
6780 /* Return true if at least one member of COMPONENT_LIST needs strict
6781 alignment. */
6783 static bool
6785 {
6786 Node_Id component_decl;
6791 {
6799 }
6802 }
6804 /* Return true if TYPE is a type with variable size or a padding type with a
6805 field of variable size or a record that has a field with such a type. */
6807 static bool
6809 {
6810 tree field;
6827 }
6828 \f
6829 /* Return true if FIELD is an artificial field. */
6831 static bool
6833 {
6834 /* These fields are generated by the front-end proper. */
6838 /* These fields are generated by gigi. */
6843 }
6845 /* Return true if FIELD is a non-artificial aliased field. */
6847 static bool
6849 {
6854 }
6856 /* Return true if FIELD is a non-artificial field with self-referential
6857 size. */
6859 static bool
6861 {
6869 }
6871 /* Return true if FIELD is a non-artificial field with variable size. */
6873 static bool
6875 {
6883 }
6885 /* qsort comparer for the bit positions of two record components. */
6887 static int
6889 {
6892 const int ret
6896 }
6898 /* Structure holding information for a given variant. */
6900 {
6901 /* The record type of the variant. */
6902 tree type;
6904 /* The name of the variant. */
6905 tree name;
6907 /* The qualifier of the variant. */
6908 tree qual;
6910 /* Whether the variant has a rep clause. */
6913 /* Whether the variant is packed. */
6918 /* Translate and chain the GNAT_COMPONENT_LIST to the GNU_FIELD_LIST, set the
6919 result as the field list of GNU_RECORD_TYPE and finish it up. Return true
6920 if GNU_RECORD_TYPE has a rep clause which affects the layout (see below).
6921 When called from gnat_to_gnu_entity during the processing of a record type
6922 definition, the GCC node for the parent, if any, will be the single field
6923 of GNU_RECORD_TYPE and the GCC nodes for the discriminants will be on the
6924 GNU_FIELD_LIST. The other calls to this function are recursive calls for
6925 the component list of a variant and, in this case, GNU_FIELD_LIST is empty.
6927 PACKED is 1 if this is for a packed record, -1 if this is for a record
6928 with Component_Alignment of Storage_Unit, -2 if this is for a record
6929 with a specified alignment.
6931 DEFINITION is true if we are defining this record type.
6933 CANCEL_ALIGNMENT is true if the alignment should be zeroed before laying
6934 out the record. This means the alignment only serves to force fields to
6935 be bitfields, but not to require the record to be that aligned. This is
6936 used for variants.
6938 ALL_REP is true if a rep clause is present for all the fields.
6940 UNCHECKED_UNION is true if we are building this type for a record with a
6941 Pragma Unchecked_Union.
6943 ARTIFICIAL is true if this is a type that was generated by the compiler.
6945 DEBUG_INFO is true if we need to write debug information about the type.
6947 MAYBE_UNUSED is true if this type may be unused in the end; this doesn't
6948 mean that its contents may be unused as well, only the container itself.
6950 REORDER is true if we are permitted to reorder components of this type.
6952 FIRST_FREE_POS, if nonzero, is the first (lowest) free field position in
6953 the outer record type down to this variant level. It is nonzero only if
6954 all the fields down to this level have a rep clause and ALL_REP is false.
6956 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
6957 with a rep clause is to be added; in this case, that is all that should
6958 be done with such fields and the return value will be false. */
6960 static bool
6967 {
6981 /* For each component referenced in a component declaration create a GCC
6982 field and add it to the list, skipping pragmas in the GNAT list. */
6989 {
6993 /* If present, the _Parent field must have been created as the single
6994 field of the record type. Put it before any other fields. */
6996 {
6999 }
7000 else
7001 {
7005 /* If this is the _Tag field, put it before any other fields. */
7009 /* If this is the _Controller field, put it before the other
7010 fields except for the _Tag or _Parent field. */
7012 {
7015 }
7017 /* If this is a regular field, put it after the other fields. */
7018 else
7019 {
7025 /* And record information for the final layout. */
7030 }
7031 }
7034 }
7036 /* At the end of the component list there may be a variant part. */
7039 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
7040 mutually exclusive and should go in the same memory. To do this we need
7041 to treat each variant as a record whose elements are created from the
7042 component list for the variant. So here we create the records from the
7043 lists for the variants and put them all into the QUAL_UNION_TYPE.
7044 If this is an Unchecked_Union, we make a UNION_TYPE instead or
7045 use GNU_RECORD_TYPE if there are no fields so far. */
7047 {
7051 tree gnu_var_name
7062 gnu_union_name
7065 /* Reuse the enclosing union if this is an Unchecked_Union whose fields
7066 are all in the variant part, to match the layout of C unions. There
7067 is an associated check below. */
7070 else
7071 {
7072 gnu_union_type
7078 }
7080 /* If all the fields down to this level have a rep clause, find out
7081 whether all the fields at this level also have one. If so, then
7082 compute the new first free position to be passed downward. */
7085 {
7087 gnu_field;
7090 {
7093 this_first_free_pos
7095 }
7096 else
7097 {
7100 }
7101 }
7103 /* We build the variants in two passes. The bulk of the work is done in
7104 the first pass, that is to say translating the GNAT nodes, building
7105 the container types and computing the associated properties. However
7106 we cannot finish up the container types during this pass because we
7107 don't know where the variant part will be placed until the end. */
7111 {
7116 vinfo_t vinfo;
7124 /* Set the alignment of the inner type in case we need to make
7125 inner objects into bitfields, but then clear it out so the
7126 record actually gets only the alignment required. */
7130 /* Similarly, if the outer record has a size specified and all
7131 the fields have a rep clause, we can propagate the size. */
7133 {
7137 }
7139 /* Add the fields into the record type for the variant. Note that
7140 we aren't sure to really use it at this point, see below. */
7141 has_rep
7145 unchecked_union,
7147 this_first_free_pos,
7148 all_rep || this_first_free_pos
7151 /* Translate the qualifier and annotate the GNAT node. */
7155 /* Deal with packedness like in gnat_to_gnu_field. */
7157 {
7160 }
7161 else
7162 field_packed
7165 /* Push this variant onto the stack for the second pass. */
7173 /* Compute the global properties that will determine the placement of
7174 the variant part. */
7178 }
7180 /* Round up the first free position to the alignment of the variant part
7181 for the variants without rep clause. This will guarantee a consistent
7182 layout independently of the placement of the variant part. */
7186 /* In the second pass, the container types are adjusted if necessary and
7187 finished up, then the corresponding fields of the variant part are
7188 built with their qualifier, unless this is an unchecked union. */
7190 {
7194 /* If this is an Unchecked_Union whose fields are all in the variant
7195 part and we have a single field with no representation clause or
7196 placed at offset zero, use the field directly to match the layout
7197 of C unions. */
7199 && gnu_field_list
7203 {
7206 }
7207 else
7208 {
7209 /* Finalize the variant type now. We used to throw away empty
7210 record types but we no longer do that because we need them to
7211 generate complete debug info for the variant; otherwise, the
7212 union type definition will be lacking the fields associated
7213 with these empty variants. */
7215 {
7216 /* The variant part will be at offset 0 so we need to ensure
7217 that the fields are laid out starting from the first free
7218 position at this level. */
7220 tree gnu_rep_part;
7222 gnu_rep_part
7224 this_first_free_pos);
7229 }
7236 gnu_field
7238 gnu_union_type,
7239 all_rep_and_size
7248 }
7252 }
7254 /* Only make the QUAL_UNION_TYPE if there are non-empty variants. */
7256 {
7260 {
7264 }
7269 /* If GNU_UNION_TYPE is our record type, it means we must have an
7270 Unchecked_Union with no fields. Verify that and, if so, just
7271 return. */
7273 {
7275 && !gnu_field_list
7278 }
7283 /* Deal with packedness like in gnat_to_gnu_field. */
7286 else
7287 union_field_packed
7290 gnu_variant_part
7292 all_rep_and_size
7298 }
7299 }
7301 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses and, if we are
7302 permitted to reorder components, self-referential sizes or variable sizes.
7303 If they do, pull them out and put them onto the appropriate list. We have
7304 to do this in a separate pass since we want to handle the discriminants
7305 but can't play with them until we've used them in debugging data above.
7307 Similarly, pull out the fields with zero size and no rep clause, as they
7308 would otherwise modify the layout and thus very likely run afoul of the
7309 Ada semantics, which are different from those of C here.
7311 ??? If we reorder them, debugging information will be wrong but there is
7312 nothing that can be done about this at the moment. */
7315 #define MOVE_FROM_FIELD_LIST_TO(LIST) \
7316 do { \
7317 if (gnu_last) \
7318 DECL_CHAIN (gnu_last) = gnu_next; \
7319 else \
7320 gnu_field_list = gnu_next; \
7321 \
7322 DECL_CHAIN (gnu_field) = (LIST); \
7323 (LIST) = gnu_field; \
7324 } while (0)
7327 {
7331 {
7334 }
7338 {
7341 }
7344 {
7347 }
7350 {
7360 }
7363 }
7365 #undef MOVE_FROM_FIELD_LIST_TO
7369 /* If permitted, we reorder the fields as follows:
7371 1) all fixed length fields,
7372 2) all fields whose length doesn't depend on discriminants,
7373 3) all fields whose length depends on discriminants,
7374 4) the variant part,
7376 within the record and within each variant recursively. */
7378 gnu_field_list
7381 /* Otherwise, if there is an aliased field placed after a field whose length
7382 depends on discriminants, we put all the fields of the latter sort, last.
7383 We need to do this in case an object of this record type is mutable. */
7387 /* If P_REP_LIST is nonzero, this means that we are asked to move the fields
7388 in our REP list to the previous level because this level needs them in
7389 order to do a correct layout, i.e. avoid having overlapping fields. */
7393 /* Otherwise, sort the fields by bit position and put them into their own
7394 record, before the others, if we also have fields without rep clause. */
7396 {
7401 /* If all the fields have a rep clause, we can do a flat layout. */
7402 layout_with_rep = !gnu_field_list
7404 gnu_rep_type
7408 gnu_field;
7414 /* Put the fields in the list in order of increasing position, which
7415 means we start from the end. */
7418 {
7422 }
7426 else
7427 {
7430 /* If FIRST_FREE_POS is nonzero, we need to ensure that the fields
7431 without rep clause are laid out starting from this position.
7432 Therefore, we force it as a minimal size on the REP part. */
7433 gnu_rep_part
7436 /* Chain the REP part at the beginning of the field list. */
7439 }
7440 }
7442 /* Chain the variant part at the end of the field list. */
7454 /* Chain the fields with zero size at the beginning of the field list. */
7460 }
7461 \f
7462 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
7463 placed into an Esize, Component_Bit_Offset, or Component_Size value
7464 in the GNAT tree. */
7466 static Uint
7468 {
7469 TCode tcode;
7474 /* See if we've already saved the value for this node. */
7476 {
7484 }
7485 else
7488 /* If we do not return inside this switch, TCODE will be set to the
7489 code to use for a Create_Node operand and LEN (set above) will be
7490 the number of recursive calls for us to make. */
7493 {
7498 /* The only case we handle here is a simple discriminant reference. */
7500 {
7503 /* Climb up the chain of successive extensions, if any. */
7510 return
7512 }
7519 /* Now just list the operations we handle. */
7550 /* For negative values in sizetype, build NEGATE_EXPR of the opposite.
7551 Such values appear in expressions with aligning patterns. Note that,
7552 since sizetype is unsigned, we have to jump through some hoops. */
7554 {
7558 {
7561 }
7562 }
7566 /* In regular mode, inline back only if symbolic annotation is requested
7567 in order to avoid memory explosion on big discriminated record types.
7568 But not in ASIS mode, as symbolic annotation is required for DDA. */
7570 {
7574 }
7575 else
7578 /* Fall through... */
7582 }
7584 /* Now get each of the operands that's relevant for this code. If any
7585 cannot be expressed as a repinfo node, say we can't. */
7590 {
7593 else
7597 }
7601 /* Save the result in the cache. */
7603 {
7605 /* We can't assume the hash table data hasn't moved since the initial
7606 look up, so we have to search again. Allocating and inserting an
7607 entry at that point would be an alternative, but then we'd better
7608 discard the entry if we decided not to cache it. */
7614 }
7617 }
7619 /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
7620 and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
7621 size and alignment used by Gigi. Prefer SIZE over TYPE_SIZE if non-null.
7622 BY_REF is true if the object is used by reference. */
7624 void
7626 {
7628 {
7631 else
7633 }
7636 {
7645 }
7650 }
7652 /* Return first element of field list whose TREE_PURPOSE is the same as ELEM.
7653 Return NULL_TREE if there is no such element in the list. */
7655 static tree
7657 {
7659 {
7664 }
7666 }
7668 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding GCC type,
7669 set Component_Bit_Offset and Esize of the components to the position and
7670 size used by Gigi. */
7672 static void
7674 {
7675 Entity_Id gnat_field;
7676 tree gnu_list;
7678 /* We operate by first making a list of all fields and their position (we
7679 can get the size easily) and then update all the sizes in the tree. */
7680 gnu_list
7690 {
7692 gnu_list);
7694 {
7695 tree parent_offset;
7697 /* If we are just annotating types and the type is tagged, the tag
7698 and the parent components are not generated by the front-end so
7699 we need to add the appropriate offset to each component without
7700 representation clause. */
7704 {
7705 /* For a component appearing in the current extension, the
7706 offset is the size of the parent. */
7709 parent_offset
7711 bitsizetype);
7712 else
7716 parent_offset
7719 }
7720 else
7723 Set_Component_Bit_Offset
7725 annotate_value
7729 parent_offset)));
7733 }
7735 {
7736 /* If there is no entry, this is an inherited component whose
7737 position is the same as in the parent type. */
7738 Set_Component_Bit_Offset
7744 }
7745 }
7746 }
7747 \f
7748 /* Scan all fields in GNU_TYPE and return a TREE_LIST where TREE_PURPOSE is
7749 the FIELD_DECL and TREE_VALUE a TREE_VEC containing the byte position, the
7750 value to be placed into DECL_OFFSET_ALIGN and the bit position. The list
7751 of fields is flattened, except for variant parts if DO_NOT_FLATTEN_VARIANT
7752 is set to true. GNU_POS is to be added to the position, GNU_BITPOS to the
7753 bit position, OFFSET_ALIGN is the present offset alignment. GNU_LIST is a
7754 pre-existing list to be chained to the newly created entries. */
7756 static tree
7759 {
7760 tree gnu_field;
7763 gnu_field;
7765 {
7770 unsigned int our_offset_align
7779 /* Recurse on internal fields, flattening the nested fields except for
7780 those in the variant part, if requested. */
7782 {
7786 gnu_list
7790 else
7791 gnu_list
7795 }
7796 }
7799 }
7801 /* Return a list describing the substitutions needed to reflect the
7802 discriminant substitutions from GNAT_TYPE to GNAT_SUBTYPE. They can
7803 be in any order. The values in an element of the list are in the form
7804 of operands to SUBSTITUTE_IN_EXPR. DEFINITION is true if this is for
7805 a definition of GNAT_SUBTYPE. */
7809 {
7811 Entity_Id gnat_discrim;
7812 Node_Id gnat_constr;
7819 /* Ignore access discriminants. */
7821 {
7824 elaborate_expression
7830 }
7833 }
7835 /* Scan all fields in QUAL_UNION_TYPE and return a list describing the
7836 variants of QUAL_UNION_TYPE that are still relevant after applying
7837 the substitutions described in SUBST_LIST. GNU_LIST is a pre-existing
7838 list to be prepended to the newly created entries. */
7843 {
7844 tree gnu_field;
7847 gnu_field;
7849 {
7857 /* If the new qualifier is not unconditionally false, its variant may
7858 still be accessed. */
7860 {
7866 /* Recurse on the variant subpart of the variant, if any. */
7872 /* If the new qualifier is unconditionally true, the subsequent
7873 variants cannot be accessed. */
7876 }
7877 }
7880 }
7881 \f
7882 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
7883 corresponding to GNAT_OBJECT. If the size is valid, return an INTEGER_CST
7884 corresponding to its value. Otherwise, return NULL_TREE. KIND is set to
7885 VAR_DECL if we are specifying the size of an object, TYPE_DECL for the
7886 size of a type, and FIELD_DECL for the size of a field. COMPONENT_P is
7887 true if we are being called to process the Component_Size of GNAT_OBJECT;
7888 this is used only for error messages. ZERO_OK is true if a size of zero
7889 is permitted; if ZERO_OK is false, it means that a size of zero should be
7890 treated as an unspecified size. */
7892 static tree
7895 {
7896 Node_Id gnat_error_node;
7899 /* Return 0 if no size was specified. */
7903 /* Ignore a negative size since that corresponds to our back-annotation. */
7907 /* Find the node to use for error messages. */
7914 else
7917 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
7918 but cannot be represented in bitsizetype. */
7921 {
7924 gnat_object);
7925 else
7927 gnat_object);
7929 }
7931 /* Ignore a zero size if it is not permitted. */
7935 /* The size of objects is always a multiple of a byte. */
7938 {
7942 else
7946 }
7948 /* If this is an integral type or a packed array type, the front-end has
7949 already verified the size, so we need not do it here (which would mean
7950 checking against the bounds). However, if this is an aliased object,
7951 it may not be smaller than the type of the object. */
7956 /* If the object is a record that contains a template, add the size of the
7957 template to the specified size. */
7963 /* If a type needs strict alignment, a component of this type in
7964 a packed record cannot be packed and thus uses the type size. */
7967 else
7970 /* Modify the size of a discriminated type to be the maximum size. */
7974 /* If this is an access type or a fat pointer, the minimum size is that given
7975 by the smallest integral mode that's valid for pointers. */
7977 {
7982 }
7984 /* Issue an error either if the default size of the object isn't a constant
7985 or if the new size is smaller than it. */
7989 {
7991 post_error_ne_tree
7994 else
7995 post_error_ne_tree
7999 }
8002 }
8003 \f
8004 /* Similarly, but both validate and process a value of RM size. This routine
8005 is only called for types. */
8007 static void
8009 {
8010 Node_Id gnat_attr_node;
8013 /* Do nothing if no size was specified. */
8017 /* Ignore a negative size since that corresponds to our back-annotation. */
8021 /* Only issue an error if a Value_Size clause was explicitly given.
8022 Otherwise, we'd be duplicating an error on the Size clause. */
8023 gnat_attr_node
8026 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
8027 but cannot be represented in bitsizetype. */
8030 {
8033 gnat_entity);
8035 }
8037 /* Ignore a zero size unless a Value_Size clause exists, or a size clause
8038 exists, or this is an integer type, in which case the front-end will
8039 have always set it. */
8048 /* If the old size is self-referential, get the maximum size. */
8052 /* Issue an error either if the old size of the object isn't a constant or
8053 if the new size is smaller than it. The front-end has already verified
8054 this for scalar and packed array types. */
8062 && TYPE_PACKED_ARRAY_TYPE_P
8065 {
8067 post_error_ne_tree
8071 }
8073 /* Otherwise, set the RM size proper for integral types... */
8080 /* ...or the Ada size for record and union types. */
8084 }
8085 \f
8086 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
8087 a type or object whose present alignment is ALIGN. If this alignment is
8088 valid, return it. Otherwise, give an error and return ALIGN. */
8090 static unsigned int
8092 {
8095 Node_Id gnat_error_node;
8097 /* Don't worry about checking alignment if alignment was not specified
8098 by the source program and we already posted an error for this entity. */
8102 /* Post the error on the alignment clause if any. Note, for the implicit
8103 base type of an array type, the alignment clause is on the first
8104 subtype. */
8112 gnat_error_node =
8115 else
8118 /* Within GCC, an alignment is an integer, so we must make sure a value is
8119 specified that fits in that range. Also, there is an upper bound to
8120 alignments we can support/allow. */
8128 {
8132 /* If the default alignment of "double" or larger scalar types is
8133 specifically capped and the new alignment is above the cap, do
8134 not post an error and change the alignment only if there is an
8135 alignment clause; this makes it possible to have the associated
8136 GCC type overaligned by default for performance reasons. */
8138 {
8139 Entity_Id gnat_type
8141 is_capped_double
8143 }
8145 {
8146 Entity_Id gnat_type
8148 is_capped_double
8150 }
8151 else
8155 {
8158 }
8159 else
8160 {
8167 }
8168 }
8169 else
8170 {
8174 }
8177 }
8178 \f
8179 /* Verify that TYPE is something we can implement atomically. If not, issue
8180 an error for GNAT_ENTITY. COMPONENT_P is true if we are being called to
8181 process a component type. */
8183 static void
8185 {
8187 Node_Id gnat_node;
8188 machine_mode mode;
8191 tree size;
8193 /* If this is an anonymous base type, nothing to check, the error will be
8194 reported on the source type if need be. */
8203 /* Consider all aligned floating-point types atomic and any aligned types
8204 that are represented by integers no wider than a machine word. */
8211 /* For the moment, also allow anything that has an alignment equal to its
8212 size and which is smaller than a word. */
8223 {
8224 unsigned char pragma_id
8229 {
8232 }
8233 }
8241 else
8244 }
8245 \f
8247 /* Helper for the intrin compatibility checks family. Evaluate whether
8248 two types are definitely incompatible. */
8250 static bool
8252 {
8267 {
8274 /* Assume designated types are ok. We'd need to account for char * and
8275 void * variants to do better, which could rapidly get messy and isn't
8276 clearly worth the effort. */
8281 }
8284 }
8286 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8287 on the Ada/builtin argument lists for the INB binding. */
8289 static bool
8291 {
8297 /* Sequence position of the last argument we checked. */
8301 {
8305 /* If we've exhausted both lists simultaneously, we're done. */
8309 /* If one list is shorter than the other, they fail to match. */
8313 /* If we're done with the Ada args and not with the internal builtin
8314 args, or the other way around, complain. */
8317 {
8320 }
8324 {
8328 }
8330 /* Otherwise, check that types match for the current argument. */
8331 argpos ++;
8333 {
8337 }
8342 }
8345 }
8347 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8348 on the Ada/builtin return values for the INB binding. */
8350 static bool
8352 {
8356 /* Accept function imported as procedure, common and convenient. */
8361 /* If return type is Address (integer type), map it to void *. */
8365 /* Check return types compatibility otherwise. Note that this
8366 handles void/void as well. */
8368 {
8372 }
8375 }
8377 /* Check and return whether the Ada and gcc builtin profiles bound by INB are
8378 compatible. Issue relevant warnings when they are not.
8380 This is intended as a light check to diagnose the most obvious cases, not
8381 as a full fledged type compatibility predicate. It is the programmer's
8382 responsibility to ensure correctness of the Ada declarations in Imports,
8383 especially when binding straight to a compiler internal. */
8385 static bool
8387 {
8388 /* Check compatibility on return values and argument lists, each responsible
8389 for posting warnings as appropriate. Ensure use of the proper sloc for
8390 this purpose. */
8403 }
8404 \f
8405 /* Return a FIELD_DECL node modeled on OLD_FIELD. FIELD_TYPE is its type
8406 and RECORD_TYPE is the type of the parent. If SIZE is nonzero, it is the
8407 specified size for this field. POS_LIST is a position list describing
8408 the layout of OLD_FIELD and SUBST_LIST a substitution list to be applied
8409 to this layout. */
8411 static tree
8415 {
8427 /* If the position is now a constant, we can set it as the position of the
8428 field when we make it. Otherwise, we need to deal with it specially. */
8431 else
8434 new_field
8440 {
8442 /* Finalize the position. */
8451 }
8459 }
8461 /* Create the REP part of RECORD_TYPE with REP_TYPE. If MIN_SIZE is nonzero,
8462 it is the minimal size the REP_PART must have. */
8464 static tree
8466 {
8467 tree field;
8477 }
8479 /* Return the REP part of RECORD_TYPE, if any. Otherwise return NULL. */
8481 static tree
8483 {
8486 /* The REP part is the first field, internal, another record, and its name
8487 starts with an 'R'. */
8495 }
8497 /* Return the variant part of RECORD_TYPE, if any. Otherwise return NULL. */
8499 tree
8501 {
8502 tree field;
8504 /* The variant part is the only internal field that is a qualified union. */
8511 }
8513 /* Return a new variant part modeled on OLD_VARIANT_PART. VARIANT_LIST is
8514 the list of variants to be used and RECORD_TYPE is the type of the parent.
8515 POS_LIST is a position list describing the layout of fields present in
8516 OLD_VARIANT_PART and SUBST_LIST a substitution list to be applied to this
8517 layout. */
8519 static tree
8524 {
8532 /* First create the type of the variant part from that of the old one. */
8538 /* If the position of the variant part is constant, subtract it from the
8539 size of the type of the parent to get the new size. This manual CSE
8540 reduces the code size when not optimizing. */
8542 {
8552 first_bit));
8555 }
8556 else
8559 /* Now finish up the new variants and populate the union type. */
8561 {
8565 /* Skip variants that don't belong to this nesting level. */
8569 /* Retrieve the list of fields already added to the new variant. */
8573 /* If the old variant had a variant subpart, we need to create a new
8574 variant subpart and add it to the field list. */
8578 {
8579 tree new_variant_subpart
8584 }
8586 /* Finish up the new variant and create the field. No need for debug
8587 info thanks to the XVS type. */
8591 Empty);
8593 new_field
8601 }
8603 /* Finish up the union type and create the variant part. No need for debug
8604 info thanks to the XVS type. Note that we don't reverse the field list
8605 because VARIANT_LIST has been traversed in reverse order. */
8609 Empty);
8611 new_variant_part
8617 /* With multiple discriminants it is possible for an inner variant to be
8618 statically selected while outer ones are not; in this case, the list
8619 of fields of the inner variant is not flattened and we end up with a
8620 qualified union with a single member. Drop the useless container. */
8622 {
8631 }
8634 }
8636 /* Copy the size (and alignment and alias set) from OLD_TYPE to NEW_TYPE,
8637 which are both RECORD_TYPE, after applying the substitutions described
8638 in SUBST_LIST. */
8640 static void
8643 {
8667 SET_TYPE_ADA_SIZE
8671 /* Finalize the size. */
8674 }
8676 /* Add a parallel type to GNU_TYPE, the translation of GNAT_ENTITY, which is
8677 the implementation type of a packed array type (Is_Packed_Array_Impl_Type).
8678 The parallel type is the original array type if it has been translated. */
8680 static void
8682 {
8683 Entity_Id gnat_original_array_type
8685 tree gnu_original_array_type;
8696 }
8697 \f
8698 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a
8699 type with all size expressions that contain F in a PLACEHOLDER_EXPR
8700 updated by replacing F with R.
8702 The function doesn't update the layout of the type, i.e. it assumes
8703 that the substitution is purely formal. That's why the replacement
8704 value R must itself contain a PLACEHOLDER_EXPR. */
8706 tree
8708 {
8709 tree nt;
8714 {
8720 /* First the domain types of arrays. */
8723 {
8735 SET_TYPE_INDEX_TYPE
8739 }
8741 /* Then the subtypes. */
8744 {
8756 }
8768 /* These should never show up here. */
8772 {
8789 }
8794 {
8796 tree field;
8798 /* Start out with no fields, make new fields, and chain them
8799 in. If we haven't actually changed the type of any field,
8800 discard everything we've done and return the old type. */
8805 {
8810 {
8813 }
8817 {
8820 }
8822 /* Do the substitution inside the qualifier, if any. */
8824 {
8827 {
8830 }
8831 }
8838 }
8848 }
8852 }
8853 }
8854 \f
8855 /* Return the RM size of GNU_TYPE. This is the actual number of bits
8856 needed to represent the object. */
8858 tree
8860 {
8861 /* For integral types, we store the RM size explicitly. */
8865 /* Return the RM size of the actual data plus the size of the template. */
8868 return
8873 /* For record or union types, we store the size explicitly. */
8879 /* For other types, this is just the size. */
8881 }
8882 \f
8883 /* Return the name to be used for GNAT_ENTITY. If a type, create a
8884 fully-qualified name, possibly with type information encoding.
8885 Otherwise, return the name. */
8889 {
8892 }
8894 tree
8896 {
8899 }
8901 /* Return an identifier representing the external name to be used for
8902 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
8903 and the specified suffix. */
8905 tree
8907 {
8915 /* A variable using the Stdcall convention lives in a DLL. We adjust
8916 its name to use the jump table, the _imp__NAME contains the address
8917 for the NAME variable. */
8920 {
8926 }
8929 }
8931 /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
8932 string, return a new IDENTIFIER_NODE that is the concatenation of
8933 the name followed by "___" and the specified suffix. */
8935 tree
8937 {
8944 }
8946 /* Initialize data structures of the decl.c module. */
8948 void
8950 {
8951 /* Initialize the cache of annotated values. */
8953 }
8955 /* Destroy data structures of the decl.c module. */
8957 void
8959 {
8960 /* Destroy the cache of annotated values. */
8963 }