| blob | c7d61763db10e6f5f72c29e299bc1c6862bf171e |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2021, 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 ****************************************************************************/
55 /* The "stdcall" convention is really supported on 32-bit x86/Windows only.
56 The following macro is a helper to avoid having to check for a Windows
57 specific attribute throughout this unit. */
59 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
60 #ifdef TARGET_64BIT
61 #define Has_Stdcall_Convention(E) \
62 (!TARGET_64BIT && Convention (E) == Convention_Stdcall)
63 #else
64 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
65 #endif
66 #else
67 #define Has_Stdcall_Convention(E) 0
68 #endif
72 /* Stack realignment is necessary for functions with foreign conventions when
73 the ABI doesn't mandate as much as what the compiler assumes - that is, up
74 to PREFERRED_STACK_BOUNDARY.
76 Such realignment can be requested with a dedicated function type attribute
77 on the targets that support it. We define FOREIGN_FORCE_REALIGN_STACK to
78 characterize the situations where the attribute should be set. We rely on
79 compiler configuration settings for 'main' to decide. */
81 #ifdef MAIN_STACK_BOUNDARY
82 #define FOREIGN_FORCE_REALIGN_STACK \
83 (MAIN_STACK_BOUNDARY < PREFERRED_STACK_BOUNDARY)
84 #else
85 #define FOREIGN_FORCE_REALIGN_STACK 0
86 #endif
88 /* The largest TYPE_ARRAY_MAX_SIZE value we set on an array type.
89 It's an artibrary limit (256 MB) above which we consider that
90 the allocation is essentially unbounded. */
92 #define TYPE_ARRAY_SIZE_LIMIT (1 << 28)
94 struct incomplete
95 {
97 tree old_type;
98 Entity_Id full_type;
99 };
101 /* These variables are used to defer recursively expanding incomplete types
102 while we are processing a record, an array or a subprogram type. */
106 /* This variable is used to delay expanding types coming from a limited with
107 clause and completed Taft Amendment types until the end of the spec. */
111 tree discriminant;
112 tree replacement;
117 /* The type of the variant. */
118 tree type;
120 /* The associated field. */
121 tree field;
123 /* The value of the qualifier. */
124 tree qual;
126 /* The type of the variant after transformation. */
127 tree new_type;
129 /* The auxiliary data. */
130 tree aux;
134 /* A map used to cache the result of annotate_value. */
136 {
139 {
141 }
145 {
147 }
149 static int
151 {
153 }
154 };
158 /* A map used to associate a dummy type with a list of subprogram entities. */
160 {
163 };
165 void
167 {
168 }
170 void
172 {
174 }
177 {
180 {
182 }
186 {
188 }
190 static int
192 {
194 }
195 };
228 tree *);
254 /* The relevant constituents of a subprogram binding to a GCC builtin. Used
255 to pass around calls performing profile compatibility checks. */
265 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
266 entity, return the equivalent GCC tree for that entity (a ..._DECL node)
267 and associate the ..._DECL node with the input GNAT defining identifier.
269 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
270 initial value (in GCC tree form). This is optional for a variable. For
271 a renamed entity, GNU_EXPR gives the object being renamed.
273 DEFINITION is true if this call is intended for a definition. This is used
274 for separate compilation where it is necessary to know whether an external
275 declaration or a definition must be created if the GCC equivalent was not
276 created previously. */
278 tree
280 {
281 /* The construct that declared the entity. */
283 /* The object that the entity renames, if any. */
285 /* The kind of the entity. */
287 /* True if this is a type. */
289 /* True if this is an artificial entity. */
291 /* True if debug info is requested for this entity. */
293 /* True if this entity is to be considered as imported. */
294 const bool imported_p
296 /* True if this entity has a foreign convention. */
298 /* For a type, contains the equivalent GNAT node to be used in gigi. */
300 /* For a type, contains the GNAT node to be used for back-annotation. */
302 /* Temporary used to walk the GNAT tree. */
303 Entity_Id gnat_temp;
304 /* Contains the GCC DECL node which is equivalent to the input GNAT node.
305 This node will be associated with the GNAT node by calling at the end
306 of the `switch' statement. */
308 /* Contains the GCC type to be used for the GCC node. */
310 /* Contains the GCC size tree to be used for the GCC node. */
312 /* Contains the GCC name to be used for the GCC node. */
313 tree gnu_entity_name;
314 /* True if we have already saved gnu_decl as a GNAT association. This can
315 also be used to purposely avoid making such an association but this use
316 case ought not to be applied to types because it can break the deferral
317 mechanism implemented for access types. */
319 /* True if we incremented defer_incomplete_level. */
321 /* True if we incremented force_global. */
323 /* True if we should check to see if elaborated during processing. */
325 /* True if we made GNU_DECL and its type here. */
327 /* Size and alignment of the GCC node, if meaningful. */
329 /* Contains the list of attributes directly attached to the entity. */
332 /* Since a use of an itype is a definition, process it as such if it is in
333 the main unit, except for E_Access_Subtype because it's actually a use
334 of its base type, see below. */
336 && is_type
341 {
342 /* Ensure that we are in a subprogram mentioned in the Scope chain of
343 this entity, our current scope is global, or we encountered a task
344 or entry (where we can't currently accurately check scoping). */
347 {
350 }
355 {
360 gnat_temp
372 && (current_function_decl
374 {
377 }
378 }
380 /* This abort means the itype has an incorrect scope, i.e. that its
381 scope does not correspond to the subprogram it is first used in. */
383 }
385 /* If we've already processed this entity, return what we got last time.
386 If we are defining the node, we should not have already processed it.
387 In that case, we will abort below when we try to save a new GCC tree
388 for this object. We also need to handle the case of getting a dummy
389 type when a Full_View exists but be careful so as not to trigger its
390 premature elaboration. Likewise for a cloned subtype without its own
391 freeze node, which typically happens when a generic gets instantiated
392 on an incomplete or private type. */
395 {
404 {
405 gnu_decl
410 }
419 {
420 gnu_decl
425 }
428 }
430 /* If this is a numeric or enumeral type, or an access type, a nonzero Esize
431 must be specified unless it was specified by the programmer. Exceptions
432 are for access-to-protected-subprogram types and all access subtypes, as
433 another GNAT type is used to lay out the GCC type for them. */
445 /* The RM size must be specified for all discrete and fixed-point types. */
449 /* If we get here, it means we have not yet done anything with this entity.
450 If we are not defining it, it must be a type or an entity that is defined
451 elsewhere or externally, otherwise we should have defined it already.
453 In other words, the failure of this assertion typically arises when a
454 reference to an entity (type or object) is made before its declaration,
455 either directly or by means of a freeze node which is incorrectly placed.
456 This can also happen for an entity referenced out of context, for example
457 a parameter outside of the subprogram where it is declared. GNAT_ENTITY
458 is the N_Defining_Identifier of the entity, the problematic N_Identifier
459 being the argument passed to Identifier_to_gnu in the parent frame.
461 One exception is for an entity, typically an inherited operation, which is
462 a local alias for the parent's operation. It is neither defined, since it
463 is an inherited operation, nor public, since it is declared in the current
464 compilation unit, so we test Is_Public on the Alias entity instead. */
466 || is_type
476 /* Get the name of the entity and set up the line number and filename of
477 the original definition for use in any decl we make. Make sure we do
478 not inherit another source location. */
483 /* For cases when we are not defining (i.e., we are referencing from
484 another compilation unit) public entities, show we are at global level
485 for the purpose of computing scopes. Don't do this for components or
486 discriminants since the relevant test is whether or not the record is
487 being defined. */
495 /* Handle any attributes directly attached to the entity. */
499 /* Do some common processing for types. */
501 {
502 /* Compute the equivalent type to be used in gigi. */
505 /* Machine_Attributes on types are expected to be propagated to
506 subtypes. The corresponding Gigi_Rep_Items are only attached
507 to the first subtype though, so we handle the propagation here. */
514 /* Compute a default value for the size of an elementary type. */
516 {
526 else
531 }
532 }
535 {
538 {
539 /* The GNAT record where the component was defined. */
542 /* If the entity is a discriminant of an extended tagged type used to
543 rename a discriminant of the parent type, return the latter. */
547 {
548 gnu_decl
553 }
555 /* If the entity is an inherited component (in the case of extended
556 tagged record types), just return the original entity, which must
557 be a FIELD_DECL. Likewise for discriminants. If the entity is a
558 non-girder discriminant (in the case of derived untagged record
559 types), return the stored discriminant it renames. */
562 {
563 gnu_decl
566 /* GNU_DECL contains a PLACEHOLDER_EXPR for discriminants. */
570 }
572 /* Otherwise, if we are not defining this and we have no GCC type
573 for the containing record, make one for it. Then we should
574 have made our own equivalent. */
576 {
577 /* ??? If this is in a record whose scope is a protected
578 type and we have an Original_Record_Component, use it.
579 This is a workaround for major problems in protected type
580 handling. */
584 {
585 gnu_decl
589 }
590 else
591 {
594 }
598 }
600 /* Here we have no GCC type and this is a reference rather than a
601 definition. This should never happen. Most likely the cause is
602 reference before declaration in the GNAT tree for gnat_entity. */
604 }
608 {
614 /* All references are supposed to be folded in the front-end. */
620 /* Build a CONST_DECL for debugging purposes exclusively. */
621 gnu_decl
626 }
630 /* Ignore constant definitions already marked with the error node. See
631 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
635 {
638 }
640 /* Ignore deferred constant definitions without address clause since
641 they are processed fully in the front-end. If No_Initialization
642 is set, this is not a deferred constant but a constant whose value
643 is built manually. And constants that are renamings are handled
644 like variables. */
646 && !gnu_expr
650 {
654 }
656 /* If this is a use of a deferred constant without address clause,
657 get its full definition. */
661 {
662 gnu_decl
666 }
668 /* If we have a constant that we are not defining, get the expression it
669 was defined to represent. This is necessary to avoid generating dumb
670 elaboration code in simple cases, and we may throw it away later if it
671 is not a constant. But do not do it for dispatch tables because they
672 are only referenced indirectly and we need to have a consistent view
673 of the exported and of the imported declarations of the tables from
674 external units for them to be properly merged in LTO mode. Moreover
675 simply do not retrieve the expression if it is an allocator because
676 the designated type might still be dummy at this point. Note that we
677 invoke gnat_to_gnu_external and not gnat_to_gnu because the expression
678 may contain N_Expression_With_Actions nodes and thus declarations of
679 objects from other units that we need to discard. Note also that we
680 need to do it even if we are only annotating types, so as to be able
681 to validate representation clauses using constants. */
690 /* ... fall through ... */
696 {
698 /* Always create a variable for volatile objects and variables seen
699 constant but with a Linker_Section pragma. */
700 bool const_flag
712 /* We implement RM 13.3(19) for exported and imported (non-constant)
713 objects by making them volatile. */
714 bool volatile_flag
722 /* We need to translate the renamed object even though we are only
723 referencing the renaming. But it may contain a call for which
724 we'll generate a temporary to hold the return value and which
725 is part of the definition of the renaming, so discard it. */
727 {
731 else
733 }
735 /* Get the type after elaborating the renamed object. */
738 else
741 /* For a debug renaming declaration, build a debug-only entity. */
743 {
744 /* Force a non-null value to make sure the symbol is retained. */
748 integer_minus_one_node));
756 }
758 /* If this is a loop variable, its type should be the base type.
759 This is because the code for processing a loop determines whether
760 a normal loop end test can be done by comparing the bounds of the
761 loop against those of the base type, which is presumed to be the
762 size used for computation. But this is not correct when the size
763 of the subtype is smaller than the type. */
767 /* Reject non-renamed objects whose type is an unconstrained array or
768 any object whose type is a dummy type or void. */
773 {
776 force_global--;
778 }
780 /* If an alignment is specified, use it if valid. Note that exceptions
781 are objects but don't have an alignment and there is also no point in
782 setting it for an address clause, since the final type of the object
783 will be a reference type. */
790 /* Likewise, if a size is specified, use it if valid. */
792 gnu_size
797 {
798 gnu_type
804 }
806 /* If this object has self-referential size, it must be a record with
807 a default discriminant. We are supposed to allocate an object of
808 the maximum size in this case, unless it is a constant with an
809 initializing expression, in which case we can get the size from
810 that. Note that the resulting size may still be a variable, so
811 this may end up with an indirect allocation. */
814 {
816 {
820 {
821 /* If the initializing expression is itself a constant,
822 despite having a nominal type with self-referential
823 size, we can get the size directly from it. */
825 && TYPE_IS_PADDING_P
829 || DECL_READONLY_ONCE_ELAB
831 {
834 }
835 else
836 {
837 gnu_size
839 gnu_expr);
840 gnu_ada_size
842 gnu_expr);
843 }
844 }
845 }
846 /* We may have no GNU_EXPR because No_Initialization is
847 set even though there's an Expression. */
851 {
852 tree gnu_expr_type
856 }
857 else
858 {
860 /* We can be called on unconstrained arrays in this mode. */
864 }
866 /* If the size isn't constant and we are at global level, call
867 elaborate_expression_1 to make a variable for it rather than
868 calculating it each time. */
872 }
874 /* If the size is zero byte, make it one byte since some linkers have
875 troubles with zero-sized objects. If the object will have a
876 template, that will make it nonzero so don't bother. Also avoid
877 doing that for an object renaming or an object with an address
878 clause, as we would lose useful information on the view size
879 (e.g. for null array slices) and we are not allocating the object
880 here anyway. */
892 /* If this is an object with no specified size and alignment, and
893 if either it is full access or we are not optimizing alignment for
894 space and it is composite and not an exception, an Out parameter
895 or a reference to another object, and the size of its type is a
896 constant, set the alignment to the smallest one which is not
897 smaller than the size, with an appropriate cap. */
906 && !imported_p
912 /* If the object is set to have atomic components, find the component
913 type and validate it.
915 ??? Note that we ignore Has_Volatile_Components on objects; it's
916 not at all clear what to do in that case. */
918 {
927 }
929 /* If this is an aliased object with an unconstrained array nominal
930 subtype, make a type that includes the template. We will either
931 allocate or create a variable of that type, see below. */
935 {
937 gnu_type
939 gnu_type,
942 debug_info_p);
943 }
945 /* ??? If this is an object of CW type initialized to a value, try to
946 ensure that the object is sufficient aligned for this value, but
947 without pessimizing the allocation. This is a kludge necessary
948 because we don't support dynamic alignment. */
955 #ifdef MINIMUM_ATOMIC_ALIGNMENT
956 /* If the size is a constant and no alignment is specified, force
957 the alignment to be the minimum valid atomic alignment. The
958 restriction on constant size avoids problems with variable-size
959 temporaries; if the size is variable, there's no issue with
960 atomic access. Also don't do this for a constant, since it isn't
961 necessary and can interfere with constant replacement. Finally,
962 do not do it for Out parameters since that creates an
963 size inconsistency with In parameters. */
973 #endif
975 /* Do not take into account aliased adjustments or alignment promotions
976 to compute the size of the object. */
979 /* If the object is aliased, of a constrained nominal subtype and its
980 size might be zero at run time, we force at least the unit size. */
987 /* Make a new type with the desired size and alignment, if needed. */
989 {
995 /* If the nominal subtype of the object is unconstrained and its
996 size is not fixed, compute the Ada size from the Ada size of
997 the subtype and/or the expression; this will make it possible
998 for gnat_type_max_size to easily compute a maximum size. */
1002 /* If a padding record was made, declare it now since it will
1003 never be declared otherwise. This is necessary to ensure
1004 that its subtrees are properly marked. */
1008 }
1010 /* Now check if the type of the object allows atomic access. */
1014 /* If this is a renaming, avoid as much as possible to create a new
1015 object. However, in some cases, creating it is required because
1016 renaming can be applied to objects that are not names in Ada.
1017 This processing needs to be applied to the raw expression so as
1018 to make it more likely to rename the underlying object. */
1020 {
1021 /* If the renamed object had padding, strip off the reference to
1022 the inner object and reset our type. */
1025 /* Strip useless conversions around the object. */
1027 {
1030 }
1032 /* Or else, if the renamed object has an unconstrained type with
1033 default discriminant, use the padded type. */
1037 /* If this is a constant renaming stemming from a function call,
1038 treat it as a normal object whose initial value is what is being
1039 renamed. RM 3.3 says that the result of evaluating a function
1040 call is a constant object. Therefore, it can be the inner
1041 object of a constant renaming and the renaming must be fully
1042 instantiated, i.e. it cannot be a reference to (part of) an
1043 existing object. And treat other rvalues the same way. */
1047 /* Expand_Dispatching_Call can prepend a comparison of the tags
1048 before the call to "=". */
1059 /* We need to detect the case where a temporary is created to
1060 hold the return value, since we cannot safely rename it at
1061 top level as it lives only in the elaboration routine. */
1064 /* We also need to detect the case where the front-end creates
1065 a dangling 'reference to a function call at top level and
1066 substitutes it in the renaming, for example:
1068 q__b : boolean renames r__f.e (1);
1070 can be rewritten into:
1072 q__R1s : constant q__A2s := r__f'reference;
1073 [...]
1074 q__b : boolean renames q__R1s.all.e (1);
1076 We cannot safely rename the rewritten expression since the
1077 underlying object lives only in the elaboration routine. */
1079 && (inner
1083 ;
1085 /* Otherwise, this is an lvalue being renamed, so it needs to be
1086 elaborated as a reference and substituted for the entity. But
1087 this means that we must evaluate the address of the renaming
1088 in the definition case to instantiate the SAVE_EXPRs. */
1089 else
1090 {
1096 gnu_expr
1100 /* No DECL_EXPR might be created so the expression needs to be
1101 marked manually because it will likely be shared. */
1105 /* This assertion will fail if the renamed object isn't aligned
1106 enough as to make it possible to honor the alignment set on
1107 the renaming. */
1109 {
1110 const unsigned int ralign
1115 }
1117 /* The expression might not be a DECL so save it manually. */
1123 /* If this is only a reference to the entity, we are done. */
1127 /* Otherwise, emit the initialization statement, if any. */
1131 /* If it needs to be materialized for debugging purposes, build
1132 the entity as indirect reference to the renamed object. */
1134 {
1147 }
1149 /* Otherwise, instantiate the SAVE_EXPRs if needed. */
1154 }
1155 }
1157 /* If we are defining an aliased object whose nominal subtype is
1158 unconstrained, the object is a record that contains both the
1159 template and the object. If there is an initializer, it will
1160 have already been converted to the right type, but we need to
1161 create the template if there is no initializer. */
1163 && !gnu_expr
1166 /* Beware that padding might have been introduced above. */
1169 == RECORD_TYPE
1170 && TYPE_CONTAINS_TEMPLATE_P
1172 {
1173 tree template_field
1181 NULL_TREE);
1184 }
1186 /* Convert the expression to the type of the object if need be. */
1190 /* If this is a pointer that doesn't have an initializing expression,
1191 initialize it to NULL, unless the object is declared imported as
1192 per RM B.1(24). */
1195 && !gnu_expr
1199 /* If we are defining the object and it has an Address clause, we must
1200 either get the address expression from the saved GCC tree for the
1201 object if it has a Freeze node, or elaborate the address expression
1202 here since the front-end has guaranteed that the elaboration has no
1203 effects in this case. */
1205 {
1214 /* Convert the type of the object to a reference type that can
1215 alias everything as per RM 13.3(19). */
1218 gnu_type
1222 const_flag
1228 /* If this is an aliased object with an unconstrained array nominal
1229 subtype, then it can overlay only another aliased object with an
1230 unconstrained array nominal subtype and compatible template. */
1234 {
1238 /* This is the pattern built for a regular object. */
1243 /* This is the pattern built for an overaligned object. */
1246 == PLUS_EXPR
1249 gnu_address
1254 /* We make an exception for an absolute address but we warn
1255 that there is a descriptor at the start of the object. */
1257 {
1260 gnat_entity);
1263 }
1265 else
1266 {
1269 gnat_entity);
1272 }
1273 }
1275 /* If we don't have an initializing expression for the underlying
1276 variable, the initializing expression for the pointer is the
1277 specified address. Otherwise, we have to make a COMPOUND_EXPR
1278 to assign both the address and the initial value. */
1281 else
1282 gnu_expr
1286 NULL_TREE,
1287 gnu_address),
1288 gnu_expr),
1289 gnu_address);
1290 }
1292 /* If it has an address clause and we are not defining it, mark it
1293 as an indirect object. Likewise for Stdcall objects that are
1294 imported. */
1297 {
1298 /* Convert the type of the object to a reference type that can
1299 alias everything as per RM 13.3(19). */
1302 gnu_type
1309 /* No point in taking the address of an initializing expression
1310 that isn't going to be used. */
1313 /* If it has an address clause whose value is known at compile
1314 time, make the object a CONST_DECL. This will avoid a
1315 useless dereference. */
1317 {
1318 Node_Id gnat_address
1322 {
1325 }
1326 }
1327 }
1329 /* If we are at top level and this object is of variable size,
1330 make the actual type a hidden pointer to the real type and
1331 make the initializer be a memory allocation and initialization.
1332 Likewise for objects we aren't defining (presumed to be
1333 external references from other packages), but there we do
1334 not set up an initialization.
1336 If the object's size overflows, make an allocator too, so that
1337 Storage_Error gets raised. Note that we will never free
1338 such memory, so we presume it never will get allocated. */
1341 || !definition
1343 || (gnu_size
1345 size_binop
1347 bitsize_unit_node)),
1349 || !definition
1351 {
1360 /* In case this was a aliased object whose nominal subtype is
1361 unconstrained, the pointer above will be a thin pointer and
1362 build_allocator will automatically make the template.
1364 If we have a template initializer only (that we made above),
1365 pretend there is none and rely on what build_allocator creates
1366 again anyway. Otherwise (if we have a full initializer), get
1367 the data part and feed that to build_allocator.
1369 If we are elaborating a mutable object, tell build_allocator to
1370 ignore a possibly simpler size from the initializer, if any, as
1371 we must allocate the maximum possible size in this case. */
1373 {
1378 {
1379 gnu_alloc_type
1385 else
1386 gnu_expr
1387 = build_component_ref
1391 }
1396 gnat_entity);
1398 gnu_expr
1401 }
1402 else
1404 }
1406 /* If this object would go into the stack and has an alignment larger
1407 than the largest stack alignment the back-end can honor, resort to
1408 a variable of "aligning type". */
1411 && !imported_p
1412 && !static_flag
1414 {
1415 /* Create the new variable. No need for extra room before the
1416 aligned field as this is in automatic storage. */
1417 tree gnu_new_type
1421 tree gnu_new_var
1426 gnat_entity);
1428 /* Initialize the aligned field if we have an initializer. */
1430 add_stmt_with_node
1432 build_component_ref
1435 gnu_expr),
1436 gnat_entity);
1438 /* And setup this entity as a reference to the aligned field. */
1440 gnu_expr
1441 = build_unary_op
1451 }
1453 /* If this is an aggregate constant initialized to a constant, force it
1454 to be statically allocated. This saves an initialization copy. */
1456 && const_flag
1457 && gnu_expr
1466 /* If this is an aliased object with an unconstrained array nominal
1467 subtype, we make its type a thin reference, i.e. the reference
1468 counterpart of a thin pointer, so it points to the array part.
1469 This is aimed to make it easier for the debugger to decode the
1470 object. Note that we have to do it this late because of the
1471 couple of allocation adjustments that might be made above. */
1475 {
1476 /* In case the object with the template has already been allocated
1477 just above, we have nothing to do here. */
1479 {
1480 /* This variable is a GNAT encoding used by Workbench: let it
1481 go through the debugging information but mark it as
1482 artificial: users are not interested in it. */
1483 tree gnu_unc_var
1499 }
1502 gnu_type
1504 }
1506 /* Convert the expression to the type of the object if need be. */
1510 /* If this name is external or a name was specified, use it, but don't
1511 use the Interface_Name with an address clause (see cd30005). */
1517 /* Deal with a pragma Linker_Section on a constant or variable. */
1523 /* Now create the variable or the constant and set various flags. */
1524 gnu_decl
1535 /* If we are defining an Out parameter and optimization isn't enabled,
1536 create a fake PARM_DECL for debugging purposes and make it point to
1537 the VAR_DECL. Suppress debug info for the latter but make sure it
1538 will live in memory so that it can be accessed from within the
1539 debugger through the PARM_DECL. */
1541 && definition
1542 && debug_info_p
1543 && !optimize
1545 {
1552 }
1554 /* If this is a loop parameter, set the corresponding flag. */
1558 /* If this is a constant and we are defining it or it generates a real
1559 symbol at the object level and we are referencing it, we may want
1560 or need to have a true variable to represent it:
1561 - if the constant is public and not overlaid on something else,
1562 - if its address is taken,
1563 - if it is aliased,
1564 - if optimization isn't enabled, for debugging purposes. */
1571 {
1572 tree gnu_corr_var
1581 }
1583 /* If this is a constant, even if we don't need a true variable, we
1584 may need to avoid returning the initializer in every case. That
1585 can happen for the address of a (constant) constructor because,
1586 upon dereferencing it, the constructor will be reinjected in the
1587 tree, which may not be valid in every case; see lvalue_required_p
1588 for more details. */
1592 /* If this object is declared in a block that contains a block with an
1593 exception handler, and we aren't using the GCC exception mechanism,
1594 we must force this variable in memory in order to avoid an invalid
1595 optimization. */
1600 /* If this is a local variable with non-BLKmode and aggregate type,
1601 and optimization isn't enabled, then force it in memory so that
1602 a register won't be allocated to it with possible subparts left
1603 uninitialized and reaching the register allocator. */
1613 /* If we are defining an object with variable size or an object with
1614 fixed size that will be dynamically allocated, and we are using the
1615 front-end setjmp/longjmp exception mechanism, update the setjmp
1616 buffer. */
1629 gnat_entity);
1631 /* Back-annotate Esize and Alignment of the object if not already
1632 known. Note that we pick the values of the type, not those of
1633 the object, to shield ourselves from low-level platform-dependent
1634 adjustments like alignment promotion. This is both consistent with
1635 all the treatment above, where alignment and size are set on the
1636 type of the object and not on the object directly, and makes it
1637 possible to support all confirming representation clauses. */
1639 used_by_ref);
1640 }
1644 /* Return a TYPE_DECL for "void" that we previously made. */
1649 /* A special case: for the types Character and Wide_Character in
1650 Standard, we do not list all the literals. So if the literals
1651 are not specified, make this an integer type. */
1653 {
1656 else
1660 /* Set TYPE_STRING_FLAG for Character and Wide_Character types.
1661 This is needed by the DWARF-2 back-end to distinguish between
1662 unsigned integer types and character types. */
1665 /* This flag is needed by the call just below. */
1669 }
1670 else
1671 {
1672 /* We have a list of enumeral constants in First_Literal. We make a
1673 CONST_DECL for each one and build into GNU_LITERAL_LIST the list
1674 to be placed into TYPE_FIELDS. Each node is itself a TREE_LIST
1675 whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
1676 value of the literal. But when we have a regular boolean type, we
1677 simplify this a little by using a BOOLEAN_TYPE. */
1682 Entity_Id gnat_literal;
1684 /* Boolean types with foreign convention have precision 1. */
1699 {
1700 tree gnu_value
1702 /* Do not generate debug info for individual enumerators. */
1703 tree gnu_literal
1709 gnu_list
1711 }
1716 /* Note that the bounds are updated at the end of this function
1717 to avoid an infinite recursion since they refer to the type. */
1719 }
1723 /* For integer types, just make a signed type the appropriate number
1724 of bits. */
1730 {
1731 /* Small_Value is the scale factor. */
1737 /* When encoded as 1/2**N or 1/10**N, describe the scale factor as a
1738 binary or decimal scale: it is easier to read for humans. */
1742 {
1743 tree base
1745 tree exponent
1748 scale_factor
1750 integer_one_node,
1753 }
1755 /* Use the arbitrary scale factor description. Note that we support
1756 a Small_Value whose magnitude is larger than 64-bit even on 32-bit
1757 platforms, so we unconditionally use a (dummy) 128-bit type. */
1758 else
1759 {
1766 scale_factor
1768 }
1772 }
1776 {
1777 /* Packed Array Impl. Types are supposed to be subtypes only. */
1780 /* For modular types, make the unsigned type of the proper number
1781 of bits and then set up the modulus, if required. */
1784 /* Get the modulus in this type. If the modulus overflows, assume
1785 that this is because it was equal to 2**Esize. Note that there
1786 is no overflow checking done on unsigned types, so we detect the
1787 overflow by looking for a modulus of zero, which is invalid. */
1790 /* If the modulus is not 2**Esize, then this also means that the upper
1791 bound of the type, i.e. modulus - 1, is not maximal, so we create an
1792 extra subtype to carry it and set the modulus on the base type. */
1794 {
1800 gnu_type
1802 gnu_high);
1803 }
1804 }
1813 /* For integral subtypes, we make a new INTEGER_TYPE. Note that we do
1814 not want to call create_range_type since we would like each subtype
1815 node to be distinct. ??? Historically this was in preparation for
1816 when memory aliasing is implemented, but that's obsolete now given
1817 the call to relate_alias_sets below.
1819 The TREE_TYPE field of the INTEGER_TYPE points to the base type;
1820 this fact is used by the arithmetic conversion functions.
1822 We elaborate the Ancestor_Subtype if it is not in the current unit
1823 and one of our bounds is non-static. We do this to ensure consistent
1824 naming in the case where several subtypes share the same bounds, by
1825 elaborating the first such subtype first, thus using its name. */
1834 /* Set the precision to the Esize except for bit-packed arrays. */
1838 /* Boolean types with foreign convention have precision 1. */
1840 {
1846 }
1847 /* First subtypes of Character are treated as Character; otherwise
1848 this should be an unsigned type if the base type is unsigned or
1849 if the lower bound is constant and non-negative or if the type
1850 is biased. However, even if the lower bound is constant and
1851 non-negative, we use a signed type for a subtype with the same
1852 size as its signed base type, because this eliminates useless
1853 conversions to it and gives more leeway to the optimizer; but
1854 this means that we will need to explicitly test for this case
1855 when we change the representation based on the RM size. */
1867 else
1871 SET_TYPE_RM_MIN_VALUE
1874 debug_info_p));
1876 SET_TYPE_RM_MAX_VALUE
1879 debug_info_p));
1885 /* Do the same processing for Character subtypes as for types. */
1888 {
1893 }
1895 /* Inherit our alias set from what we're a subtype of. Subtypes
1896 are not different types and a pointer can designate any instance
1897 within a subtype hierarchy. */
1900 /* One of the above calls might have caused us to be elaborated,
1901 so don't blow up if so. */
1903 {
1906 }
1908 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
1912 discrete_type:
1914 /* We have to handle clauses that under-align the type specially. */
1917 && Present
1920 {
1924 }
1926 /* If the type we are dealing with represents a bit-packed array,
1927 we need to have the bits left justified on big-endian targets
1928 and right justified on little-endian targets. We also need to
1929 ensure that when the value is read (e.g. for comparison of two
1930 such values), we only get the good bits, since the unused bits
1931 are uninitialized. Both goals are accomplished by wrapping up
1932 the modular type in an enclosing record type. */
1934 {
1940 /* Make the original array type a parallel/debug type. */
1942 {
1943 tree gnu_name
1945 gnat_entity);
1948 }
1950 /* Set the RM size before wrapping up the original type. */
1954 /* Create a stripped-down declaration, mainly for debugging. */
1956 gnat_entity);
1958 /* Now save it and build the enclosing record type. */
1968 /* Propagate the alignment of the modular type to the record type,
1969 unless there is an alignment clause that under-aligns the type.
1970 This means that bit-packed arrays are given "ceil" alignment for
1971 their size by default, which may seem counter-intuitive but makes
1972 it possible to overlay them on modular types easily. */
1976 /* Propagate the reverse storage order flag to the record type so
1977 that the required byte swapping is performed when retrieving the
1978 enclosed modular value. */
1984 /* Don't declare the field as addressable since we won't be taking
1985 its address and this would prevent create_field_decl from making
1986 a bitfield. */
1987 gnu_field
1991 /* We will output additional debug info manually below. */
1995 /* Make the original array type a parallel/debug type. Note that
1996 gnat_get_array_descr_info needs a TYPE_IMPL_PACKED_ARRAY_P type
1997 so we use an intermediate step for standard DWARF. */
1999 {
2004 }
2005 }
2007 /* If the type we are dealing with has got a smaller alignment than the
2008 natural one, we need to wrap it up in a record type and misalign the
2009 latter; we reuse the padding machinery for this purpose. */
2011 {
2014 /* Set the RM size before wrapping the type. */
2017 /* Create a stripped-down declaration, mainly for debugging. */
2019 gnat_entity);
2021 gnu_type
2027 }
2032 /* The type of the Low and High bounds can be our type if this is
2033 a type from Standard, so set them at the end of the function. */
2040 /* See the E_Signed_Integer_Subtype case for the rationale. */
2057 SET_TYPE_RM_MIN_VALUE
2060 debug_info_p));
2062 SET_TYPE_RM_MAX_VALUE
2065 debug_info_p));
2067 /* Inherit our alias set from what we're a subtype of, as for
2068 integer subtypes. */
2071 /* One of the above calls might have caused us to be elaborated,
2072 so don't blow up if so. */
2076 /* Array Types and Subtypes
2078 In GNAT unconstrained array types are represented by E_Array_Type and
2079 constrained array types are represented by E_Array_Subtype. They are
2080 translated into UNCONSTRAINED_ARRAY_TYPE and ARRAY_TYPE respectively.
2081 But there are no actual objects of an unconstrained array type; all we
2082 have are pointers to that type. In addition to the type node itself,
2083 4 other types associated with it are built in the process:
2085 1. the array type (suffix XUA) containing the actual data,
2087 2. the template type (suffix XUB) containng the bounds,
2089 3. the fat pointer type (suffix XUP) representing a pointer or a
2090 reference to the unconstrained array type:
2091 XUP = struct { XUA *, XUB * }
2093 4. the object record type (suffix XUT) containing bounds and data:
2094 XUT = struct { XUB, XUA }
2096 The bounds of the array type XUA (de)reference the XUB * field of a
2097 PLACEHOLDER_EXPR for the fat pointer type XUP, so the array type XUA
2098 is to be interpreted in the context of the fat pointer type XUB for
2099 debug info purposes. */
2102 {
2103 const bool convention_fortran_p
2106 tree gnu_template_type;
2107 tree gnu_ptr_template;
2112 Entity_Id gnat_index;
2114 tree comp_type;
2116 /* Create the type for the component now, as it simplifies breaking
2117 type reference loops. */
2118 comp_type
2121 {
2122 /* As a side effect, the type may have been translated. */
2125 }
2127 /* We complete an existing dummy fat pointer type in place. This both
2128 avoids further complex adjustments in update_pointer_to and yields
2129 better debugging information in DWARF by leveraging the support for
2130 incomplete declarations of "tagged" types in the DWARF back-end. */
2133 {
2136 gnu_ptr_template =
2140 /* Save the contents of the dummy type for update_pointer_to. */
2146 }
2147 else
2148 {
2152 }
2154 /* Make a node for the array. If we are not defining the array
2155 suppress expanding incomplete types. */
2159 {
2160 defer_incomplete_level++;
2162 }
2164 /* Build the fat pointer type. Use a "void *" object instead of
2165 a pointer to the array type since we don't have the array type
2166 yet (it will reference the fat pointer via the bounds). Note
2167 that we reuse the existing fields of a dummy type because for:
2169 type Arr is array (Positive range <>) of Element_Type;
2170 type Array_Ref is access Arr;
2171 Var : Array_Ref := Null;
2173 in a declarative part, Arr will be frozen only after Var, which
2174 means that the fields used in the CONSTRUCTOR built for Null are
2175 those of the dummy type, which in turn means that COMPONENT_REFs
2176 of Var may be built with these fields. Now if COMPONENT_REFs of
2177 Var are also built later with the fields of the final type, the
2178 aliasing machinery may consider that the accesses are distinct
2179 if the FIELD_DECLs are distinct as objects. */
2181 {
2188 }
2189 else
2190 {
2191 /* We make the fields addressable for the sake of compatibility
2192 with languages for which the regular fields are addressable. */
2193 tem
2203 }
2205 /* If the GNAT encodings are used, give the fat pointer type a name.
2206 If this is a packed array, tell the debugger how to interpret the
2207 underlying bits by fetching that of the implementation type. But
2208 in any case, mark it as artificial so the debugger can skip it. */
2209 const Entity_Id gnat_name
2214 tree xup_name
2219 gnat_entity);
2221 /* Build a reference to the template from a PLACEHOLDER_EXPR that
2222 is the fat pointer. This will be used to access the individual
2223 fields once we build them. */
2227 gnu_template_reference
2232 /* Now create the GCC type for each index and add the fields for that
2233 index to the template. */
2239 {
2248 /* Update the maximum size of the array in elements. */
2250 gnu_max_size
2253 /* Now build the self-referential bounds of the index type. */
2257 /* Make the FIELD_DECLs for the low and high bounds of this
2258 type and then make extractions of these fields from the
2259 template. */
2262 gnu_index_type,
2270 gnu_index_type,
2278 /* We can't use build_component_ref here since the template type
2279 isn't complete yet. */
2282 NULL_TREE);
2285 NULL_TREE);
2291 /* Compute the size of this dimension. See the E_Array_Subtype
2292 case below for the rationale. */
2293 gnu_high
2297 gnu_max,
2300 /* Make a range type with the new range in the Ada base type.
2301 Then make an index type with the size range in sizetype. */
2305 gnu_orig_min,
2306 gnu_orig_max),
2307 gnat_entity);
2311 }
2313 /* Install all the fields into the template. */
2318 gnu_template_fields
2321 debug_info_p);
2324 /* If Component_Size is not already specified, annotate it with the
2325 size of the component. */
2330 /* Compute the maximum size of the array in units. */
2332 gnu_max_size
2335 /* Now build the array type. */
2338 {
2346 }
2348 /* If this is a packed type implemented specially, then process the
2349 implementation type so it is elaborated in the proper scope. */
2354 /* Otherwise, if an alignment is specified, use it if valid and, if
2355 the alignment was requested with an explicit clause, state so. */
2357 {
2360 gnat_entity,
2364 }
2366 /* Tag top-level ARRAY_TYPE nodes for packed arrays and their
2367 implementation types as such so that the debug information back-end
2368 can output the appropriate description for them. */
2376 /* Adjust the type of the pointer-to-array field of the fat pointer
2377 and record the aliasing relationships if necessary. */
2382 /* If the maximum size doesn't overflow, use it. */
2389 /* See the above description for the rationale. */
2395 /* Create the type to be designated by thin pointers: a record type for
2396 the array and its template. We used to shift the fields to have the
2397 template at a negative offset, but this was somewhat of a kludge; we
2398 now shift thin pointer values explicitly but only those which have a
2399 TYPE_UNCONSTRAINED_ARRAY attached to the designated RECORD_TYPE.
2400 Note that GDB can handle standard DWARF information for them, so we
2401 don't have to name them as a GNAT encoding, except if specifically
2402 asked to. */
2403 tree xut_name
2408 debug_info_p);
2413 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2414 corresponding fat pointer. */
2420 }
2425 /* This is the actual data type for array variables. Multidimensional
2426 arrays are implemented as arrays of arrays. Note that arrays which
2427 have sparse enumeration subtypes as index components create sparse
2428 arrays, which is obviously space inefficient but so much easier to
2429 code for now.
2431 Also note that the subtype never refers to the unconstrained array
2432 type, which is somewhat at variance with Ada semantics.
2434 First check to see if this is simply a renaming of the array type.
2435 If so, the result is the array type. */
2439 ;
2440 else
2441 {
2443 const bool convention_fortran_p
2452 /* First create the GCC type for each index and find out whether
2453 special types are needed for debugging information. */
2456 gnat_base_index
2462 {
2467 tree gnu_base_index_type
2473 /* We try to create subtypes for discriminants used as bounds
2474 that are more restrictive than those declared, by using the
2475 bounds of the index type of the base array type. This will
2476 make it possible to calculate the maximum size of the record
2477 type more conservatively. This may have already been done by
2478 the front-end (Exp_Ch3.Adjust_Discriminants), in which case
2479 there will be a conversion that needs to be removed first. */
2484 {
2488 gnu_base_orig_min,
2489 gnu_base_orig_max);
2490 }
2496 {
2500 gnu_base_orig_min,
2501 gnu_base_orig_max);
2502 }
2504 /* Update the maximum size of the array in elements. Here we
2505 see if any constraint on the index type of the base type
2506 can be used in the case of self-referential bounds on the
2507 index type of the array type. We look for a non-"infinite"
2508 and non-self-referential bound from any type involved and
2509 handle each bound separately. */
2511 {
2514 else
2523 else
2530 gnu_max_size
2532 }
2534 /* Convert the bounds to the base type for consistency below. */
2542 /* See if the base array type is already flat. If it is, we
2543 are probably compiling an ACATS test but it will cause the
2544 code below to malfunction if we don't handle it specially. */
2548 {
2552 }
2554 /* Similarly, if one of the values overflows in sizetype and the
2555 range is null, use 1..0 for the sizetype bounds. */
2560 {
2564 }
2566 /* If the minimum and maximum values both overflow in sizetype,
2567 but the difference in the original type does not overflow in
2568 sizetype, ignore the overflow indication. */
2572 && !TREE_OVERFLOW
2575 gnu_index_base_type,
2576 gnu_orig_max,
2577 gnu_orig_min))))
2578 {
2582 }
2584 /* Compute the size of this dimension in the general case. We
2585 need to provide GCC with an upper bound to use but have to
2586 deal with the "superflat" case. There are three ways to do
2587 this. If we can prove that the array can never be superflat,
2588 we can just use the high bound of the index type. */
2591 /* Bit-Packed Array Impl. Types are never superflat. */
2593 && Is_Bit_Packed_Array
2597 /* Otherwise, if the high bound is constant but the low bound is
2598 not, we use the expression (hb >= lb) ? lb : hb + 1 for the
2599 lower bound. Note that the comparison must be done in the
2600 original type to avoid any overflow during the conversion. */
2603 {
2605 gnu_min
2608 boolean_type_node,
2609 gnu_orig_max,
2610 gnu_orig_min),
2611 gnu_min,
2613 size_one_node));
2614 }
2616 /* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
2617 in all the other cases. Note that we use int_const_binop for
2618 the shift by 1 if the bound is constant to avoid any unwanted
2619 overflow. */
2620 else
2621 gnu_high
2624 boolean_type_node,
2625 gnu_orig_max,
2626 gnu_orig_min),
2627 gnu_max,
2630 size_one_node)
2632 size_one_node));
2634 /* Reuse the index type for the range type. Then make an index
2635 type with the size range in sizetype. */
2638 gnat_entity);
2640 /* We need special types for debugging information to point to
2641 the index types if they have variable bounds, are not integer
2642 types, are biased or are wider than sizetype. These are GNAT
2643 encodings, so we have to include them only when all encodings
2644 are requested. */
2654 }
2656 /* Then flatten: create the array of arrays. For an array type
2657 used to implement a packed array, get the component type from
2658 the original array type since the representation clauses that
2659 can affect it are on the latter. */
2662 {
2667 /* One of the above calls might have caused us to be elaborated,
2668 so don't blow up if so. */
2670 {
2673 }
2674 }
2675 else
2676 {
2678 debug_info_p);
2680 /* One of the above calls might have caused us to be elaborated,
2681 so don't blow up if so. */
2683 {
2686 }
2687 }
2689 /* Compute the maximum size of the array in units. */
2691 gnu_max_size
2694 /* Now build the array type. */
2696 {
2706 /* Kludge to remove the TREE_OVERFLOW flag for the sake of LTO
2707 on maximally-sized array types designed by access types. */
2717 {
2720 }
2721 }
2723 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
2727 /* If this is a multi-dimensional array and we are at global level,
2728 we need to make a variable corresponding to the stride of the
2729 inner dimensions. */
2731 {
2732 tree gnu_arr_type;
2737 {
2747 /* ??? For now, store the size as a multiple of the
2748 alignment of the element type in bytes so that we
2749 can see the alignment from the tree. */
2757 /* ??? create_type_decl is not invoked on the inner types so
2758 the MULT_EXPR node built above will never be marked. */
2760 }
2761 }
2763 /* Set the TYPE_PACKED flag on packed array types and also on their
2764 implementation types, so that the DWARF back-end can output the
2765 appropriate description for them. */
2774 /* If the maximum size doesn't overflow, use it. */
2781 /* If we need to write out a record type giving the names of the
2782 bounds for debugging purposes, do it now and make the record
2783 type a parallel type. This is not needed for a packed array
2784 since the bounds are conveyed by the original array type. */
2786 && debug_info_p
2788 {
2791 tree gnu_field;
2797 {
2801 /* Make sure to reference the types themselves, and not just
2802 their names, as the debugger may fall back on them. */
2808 }
2812 }
2814 /* If this is a packed array type, make the original array type a
2815 parallel/debug type. Otherwise, if GNAT encodings are used, do
2816 it for the base array type if it is not artificial to make sure
2817 that it is kept in the debug info. */
2819 {
2821 {
2822 tree gnu_name
2824 gnat_entity);
2827 }
2830 {
2831 tree gnu_base_decl
2838 }
2839 }
2841 /* Set our alias set to that of our base type. This gives all
2842 array subtypes the same alias set. */
2845 /* If this is a packed type implemented specially, then replace our
2846 type with the implementation type. */
2848 {
2849 /* First finish the type we had been making so that we output
2850 debugging information for it. */
2853 {
2854 const int quals
2855 = TYPE_QUAL_VOLATILE
2858 }
2859 /* Make it artificial only if the base type was artificial too.
2860 That's sort of "morally" true and will make it possible for
2861 the debugger to look it up by name in DWARF, which is needed
2862 in order to decode the packed array type. */
2863 tree gnu_tmp_decl
2867 gnat_entity);
2868 /* Save it as our equivalent in case the call below elaborates
2869 this type again. */
2872 gnu_type
2876 /* Set the ___XP suffix for GNAT encodings. */
2886 /* We need to attach the index type to the type we just made so
2887 that the actual bounds can later be put into a template. */
2892 {
2894 {
2895 /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
2896 TYPE_MODULUS for modular types so we make an extra
2897 subtype if necessary. */
2899 gnu_inner
2906 /* Check for other cases of overloading. */
2908 }
2913 SET_TYPE_ACTUAL_BOUNDS
2920 SET_TYPE_ACTUAL_BOUNDS
2926 }
2927 }
2928 }
2932 /* Create the type for a string literal. */
2933 {
2934 Entity_Id gnat_full_type
2939 tree gnu_string_array_type
2941 tree gnu_string_index_type
2944 tree gnu_lower_bound
2947 tree gnu_length
2949 gnu_string_index_type);
2950 tree gnu_upper_bound
2952 gnu_lower_bound,
2955 integer_one_node)));
2956 tree gnu_index_type
2960 gnu_lower_bound,
2961 gnu_upper_bound),
2962 gnat_entity);
2964 gnu_type
2967 gnu_index_type);
2971 }
2974 /* Record Types and Subtypes
2976 A record type definition is transformed into the equivalent of a C
2977 struct definition. The fields that are the discriminants which are
2978 found in the Full_Type_Declaration node and the elements of the
2979 Component_List found in the Record_Type_Definition node. The
2980 Component_List can be a recursive structure since each Variant of
2981 the Variant_Part of the Component_List has a Component_List.
2983 Processing of a record type definition comprises starting the list of
2984 field declarations here from the discriminants and the calling the
2985 function components_to_record to add the rest of the fields from the
2986 component list and return the gnu type node. The function
2987 components_to_record will call itself recursively as it traverses
2988 the tree. */
2991 {
2995 {
2996 const Node_Id first_component
2998 tree gnu_component_type
3002 }
3004 Node_Id gnat_constr;
3007 tree gnu_get_parent;
3008 /* Set PACKED in keeping with gnat_to_gnu_field. */
3009 const int packed
3017 const bool is_extension
3020 const bool has_rep
3021 = is_extension
3027 /* See if all fields have a rep clause. Stop when we find one
3028 that doesn't. */
3036 {
3039 }
3041 /* If this is a record extension, go a level further to find the
3042 record definition. Also, verify we have a Parent_Subtype. */
3044 {
3051 }
3053 /* Make a node for the record type. */
3060 /* If the record type has discriminants, pointers to it may also point
3061 to constrained subtypes of it, so mark it as may_alias for LTO. */
3063 prepend_one_attribute
3066 gnat_entity);
3070 /* If we are not defining it, suppress expanding incomplete types. */
3072 {
3073 defer_incomplete_level++;
3075 }
3077 /* If both a size and rep clause were specified, put the size on
3078 the record type now so that it can get the proper layout. */
3083 /* Always set the alignment on the record type here so that it can
3084 get the proper layout. */
3089 else
3090 {
3093 /* If a type needs strict alignment, then its type size will also
3094 be the RM size (see below). Cap the alignment if needed, lest
3095 it may cause this type size to become too large. */
3097 {
3102 }
3104 /* Similarly if an Object_Size clause has been specified. */
3106 {
3111 }
3112 }
3114 /* If we have a Parent_Subtype, make a field for the parent. If
3115 this record has rep clauses, force the position to zero. */
3117 {
3120 tree gnu_parent;
3123 /* A major complexity here is that the parent subtype will
3124 reference our discriminants in its Stored_Constraint list.
3125 But those must reference the parent component of this record
3126 which is precisely of the parent subtype we have not built yet!
3127 To break the circle we first build a dummy COMPONENT_REF which
3128 represents the "get to the parent" operation and initialize
3129 each of those discriminants to a COMPONENT_REF of the above
3130 dummy parent referencing the corresponding discriminant of the
3131 base type of the parent subtype. */
3136 gnu_dummy_parent_type),
3137 NULL_TREE);
3144 {
3145 tree gnu_field
3148 save_gnu_tree
3153 }
3155 /* Then we build the parent subtype. If it has discriminants but
3156 the type itself has unknown discriminants, this means that it
3157 doesn't contain information about how the discriminants are
3158 derived from those of the ancestor type, so it cannot be used
3159 directly. Instead it is built by cloning the parent subtype
3160 of the underlying record view of the type, for which the above
3161 derivation of discriminants has been made explicit. */
3164 {
3167 /* If we are defining the type, the underlying record
3168 view must already have been elaborated at this point.
3169 Otherwise do it now as its parent subtype cannot be
3170 technically elaborated on its own. */
3173 else
3178 /* Substitute the "get to the parent" of the type for that
3179 of its underlying record view in the cloned type. */
3184 {
3186 tree gnu_ref
3189 gnu_parent
3191 }
3192 }
3193 else
3196 /* The parent field needs strict alignment so, if it is to
3197 be created with a component clause below, then we need
3198 to apply the same adjustment as in gnat_to_gnu_field. */
3200 {
3201 /* ??? For historical reasons, we do it on strict-alignment
3202 platforms only, where it is really required. This means
3203 that a confirming representation clause will change the
3204 behavior of the compiler on the other platforms. */
3207 else
3208 parent_packed
3210 }
3212 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
3213 initially built. The discriminants must reference the fields
3214 of the parent subtype and not those of its base type for the
3215 placeholder machinery to properly work. */
3217 {
3218 /* The actual parent subtype is the full view. */
3220 {
3223 else
3225 }
3231 {
3232 Entity_Id field;
3241 }
3242 }
3244 /* The "get to the parent" COMPONENT_REF must be given its
3245 proper type... */
3248 /* ...and reference the _Parent field of this record. */
3249 gnu_field
3252 has_rep
3254 has_rep
3260 }
3262 /* Make the fields for the discriminants and put them into the record
3263 unless it's an Unchecked_Union. */
3268 {
3269 /* If this is a record extension and this discriminant is the
3270 renaming of another discriminant, we've handled it above. */
3275 gnu_field
3277 debug_info_p);
3279 /* Make an expression using a PLACEHOLDER_EXPR from the
3280 FIELD_DECL node just created and link that with the
3281 corresponding GNAT defining identifier. */
3289 {
3292 }
3293 }
3295 /* If we have a derived untagged type that renames discriminants in
3296 the parent type, the (stored) discriminants are just a copy of the
3297 discriminants of the parent type. This means that any constraints
3298 added by the renaming in the derivation are disregarded as far as
3299 the layout of the derived type is concerned. To rescue them, we
3300 change the type of the (stored) discriminants to a subtype with
3301 the bounds of the type of the visible discriminants. */
3303 && !is_extension
3309 /* Ignore access discriminants. */
3312 {
3315 tree gnu_ref
3319 /* GNU_REF must be an expression using a PLACEHOLDER_EXPR built
3320 just above for one of the stored discriminants. */
3328 }
3330 /* If this is a derived type with discriminants and these discriminants
3331 affect the initial shape it has inherited, factor them in. */
3333 && !is_extension
3341 {
3342 tree gnu_parent_type
3351 /* Set the layout of the type to match that of the parent type,
3352 doing required substitutions. If we are in minimal GNAT
3353 encodings mode, we don't need debug info for the inner record
3354 types, as they will be part of the embedding variant record's
3355 debug info. */
3356 copy_and_substitute_in_layout
3358 gnu_subst_list,
3360 }
3361 else
3362 {
3363 /* Add the fields into the record type and finish it up. */
3370 NULL);
3372 /* Empty classes have the size of a storage unit in C++. */
3375 {
3379 }
3381 /* If the type needs strict alignment, then no object of the type
3382 may have a size smaller than the natural size, which means that
3383 the RM size of the type is equal to the type size. */
3387 /* If there are entities in the chain corresponding to components
3388 that we did not elaborate, ensure we elaborate their types if
3389 they are itypes. */
3398 }
3400 /* Fill in locations of fields. */
3402 }
3406 /* If an equivalent type is present, that is what we should use.
3407 Otherwise, fall through to handle this like a record subtype
3408 since it may have constraints. */
3410 {
3414 }
3416 /* ... fall through ... */
3419 /* If Cloned_Subtype is Present it means this record subtype has
3420 identical layout to that type or subtype and we should use
3421 that GCC type for this one. The front-end guarantees that
3422 the component list is shared. */
3424 {
3430 }
3432 /* Otherwise, first ensure the base type is elaborated. Then, if we are
3433 changing the type, make a new type with each field having the type of
3434 the field in the new subtype but the position computed by transforming
3435 every discriminant reference according to the constraints. We don't
3436 see any difference between private and non-private type here since
3437 derivations from types should have been deferred until the completion
3438 of the private type. */
3439 else
3440 {
3444 {
3445 defer_incomplete_level++;
3447 }
3449 tree gnu_base_type
3453 {
3456 }
3458 /* When the subtype has discriminants and these discriminants affect
3459 the initial shape it has inherited, factor them in. But for an
3460 Unchecked_Union (it must be an itype), just return the type. */
3465 {
3468 tree gnu_unpad_base_type;
3477 /* Set the size, alignment and alias set of the type to match
3478 those of the base type, doing required substitutions. */
3480 gnu_subst_list);
3484 else
3487 /* Set the layout of the type to match that of the base type,
3488 doing required substitutions. We will output debug info
3489 manually below so pass false as last argument. */
3494 /* Fill in locations of fields. */
3497 /* If debugging information is being written for the type and if
3498 we are asked to output such encodings, write a record that
3499 shows what we are a subtype of and also make a variable that
3500 indicates our size, if still variable. */
3503 {
3505 tree gnu_unpad_base_name
3513 build_reference_type
3515 gnu_subtype_marker,
3532 }
3534 /* Or else, if the subtype is artificial and encodings are not
3535 used, use the base record type as the debug type. */
3537 && artificial_p
3540 }
3542 /* Otherwise, go down all the components in the new type and make
3543 them equivalent to those in the base type. */
3544 else
3545 {
3555 gnat_to_gnu_field_decl
3558 }
3559 }
3564 /* Use the special descriptor type for dispatch tables if needed,
3565 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3566 Note that we are only required to do so for static tables in
3567 order to be compatible with the C++ ABI, but Ada 2005 allows
3568 to extend library level tagged types at the local level so
3569 we do it in the non-static case as well. */
3572 {
3576 }
3578 /* ... fall through ... */
3585 {
3586 /* The designated type and its equivalent type for gigi. */
3589 /* Whether it comes from a limited with. */
3590 const bool is_from_limited_with
3593 /* Whether it is a completed Taft Amendment type. Such a type is to
3594 be treated as coming from a limited with clause if it is not in
3595 the main unit, i.e. we break potential circularities here in case
3596 the body of an external unit is loaded for inter-unit inlining. */
3597 const bool is_completed_taft_type
3601 /* The "full view" of the designated type. If this is an incomplete
3602 entity from a limited with, treat its non-limited view as the full
3603 view. Otherwise, if this is an incomplete or private type, use the
3604 full view. In the former case, we might point to a private type,
3605 in which case, we need its full view. Also, we want to look at the
3606 actual type used for the representation, so this takes a total of
3607 three steps. */
3608 Entity_Id gnat_desig_full_direct_first
3609 = (is_from_limited_with
3613 Entity_Id gnat_desig_full_direct
3614 = ((is_from_limited_with
3619 Entity_Id gnat_desig_full
3621 /* The type actually used to represent the designated type, either
3622 gnat_desig_full or gnat_desig_equiv. */
3623 Entity_Id gnat_desig_rep;
3624 /* We want to know if we'll be seeing the freeze node for any
3625 incomplete type we may be pointing to. */
3626 const bool in_main_unit
3630 /* True if we make a dummy type here. */
3632 /* The mode to be used for the pointer type. */
3633 scalar_int_mode p_mode;
3634 /* The GCC type used for the designated type. */
3641 /* If either the designated type or its full view is an unconstrained
3642 array subtype, replace it with the type it's a subtype of. This
3643 avoids problems with multiple copies of unconstrained array types.
3644 Likewise, if the designated type is a subtype of an incomplete
3645 record type, use the parent type to avoid order of elaboration
3646 issues. This can lose some code efficiency, but there is no
3647 alternative. */
3658 /* Set the type that's the representation of the designated type. */
3659 gnat_desig_rep
3662 /* If we already know what the full type is, use it. */
3666 /* Get the type of the thing we are to point to and build a pointer to
3667 it. If it is a reference to an incomplete or private type with a
3668 full view that is a record, an array or an access, make a dummy type
3669 and get the actual type later when we have verified it is safe. */
3676 /* Likewise if this is a reference to a record, an array or a
3677 subprogram type and we are to defer elaborating incomplete
3678 types. We do this because this access type may be the full
3679 view of a private type. */
3686 /* If this is a reference from a limited_with type back to our
3687 main unit and there's a freeze node for it, either we have
3688 already processed the declaration and made the dummy type,
3689 in which case we just reuse the latter, or we have not yet,
3690 in which case we make the dummy type and it will be reused
3691 when the declaration is finally processed. In both cases,
3692 the pointer eventually created below will be automatically
3693 adjusted when the freeze node is processed. */
3694 || (in_main_unit
3695 && is_from_limited_with
3697 {
3700 }
3702 /* Otherwise handle the case of a pointer to itself. */
3704 {
3705 gnu_type
3709 }
3711 /* If expansion is disabled, the equivalent type of a concurrent type
3712 is absent, so we use the void pointer type. */
3716 /* If the ultimately designated type is an incomplete type with no full
3717 view, we use the void pointer type in LTO mode to avoid emitting a
3718 dummy type in the GIMPLE IR. We cannot do that in regular mode as
3719 the name of the dummy type in used by GDB for a global lookup. */
3725 /* Finally, handle the default case where we can just elaborate our
3726 designated type. */
3727 else
3730 /* It is possible that a call to gnat_to_gnu_type above resolved our
3731 type. If so, just return it. */
3733 {
3736 }
3738 /* Access-to-unconstrained-array types need a special treatment. */
3740 {
3741 /* If the processing above got something that has a pointer, then
3742 we are done. This could have happened either because the type
3743 was elaborated or because somebody else executed the code. */
3748 }
3750 /* If we haven't done it yet, build the pointer type the usual way. */
3752 {
3753 /* Modify the designated type if we are pointing only to constant
3754 objects, but don't do it for a dummy type. */
3757 gnu_desig_type
3760 gnu_type
3763 }
3765 /* If the designated type is not declared in the main unit and we made
3766 a dummy node for it, save our definition, elaborate the actual type
3767 and replace the dummy type we made with the actual one. But if we
3768 are to defer actually looking up the actual type, make an entry in
3769 the deferred list instead. If this is from a limited with, we may
3770 have to defer until the end of the current unit. */
3772 {
3774 gnu_type
3780 gnat_entity);
3787 && !is_from_limited_with
3789 {
3792 }
3793 else
3794 {
3804 }
3805 }
3806 }
3811 /* If we are just annotating types and have no equivalent record type,
3812 just use the void pointer type. */
3816 /* The run-time representation is the equivalent type. */
3817 else
3818 {
3821 }
3823 /* The designated subtype must be elaborated as well, if it does
3824 not have its own freeze node. */
3835 /* We treat this as identical to its base type; any constraint is
3836 meaningful only to the front-end. */
3840 /* The designated subtype must be elaborated as well, if it does
3841 not have its own freeze node. But designated subtypes created
3842 for constrained components of records with discriminants are
3843 not frozen by the front-end and not elaborated here, because
3844 their use may appear before the base type is frozen and it is
3845 not clear that they are needed in gigi. With the current model,
3846 there is no correct place where they could be elaborated. */
3851 {
3852 /* If we are to defer elaborating incomplete types, make a dummy
3853 type node and elaborate it later. */
3855 {
3858 p->old_type
3863 }
3868 }
3871 /* Subprogram Entities
3873 The following access functions are defined for subprograms:
3875 Etype Return type or Standard_Void_Type.
3876 First_Formal The first formal parameter.
3877 Is_Imported Indicates that the subprogram has appeared in
3878 an INTERFACE or IMPORT pragma. For now we
3879 assume that the external language is C.
3880 Is_Exported Likewise but for an EXPORT pragma.
3881 Is_Inlined True if the subprogram is to be inlined.
3883 Each parameter is first checked by calling must_pass_by_ref on its
3884 type to determine if it is passed by reference. For parameters which
3885 are copied in, if they are Ada In Out or Out parameters, their return
3886 value becomes part of a record which becomes the return type of the
3887 function (C function - note that this applies only to Ada procedures
3888 so there is no Ada return type). Additional code to store back the
3889 parameters will be generated on the caller side. This transformation
3890 is done here, not in the front-end.
3892 The intended result of the transformation can be seen from the
3893 equivalent source rewritings that follow:
3895 struct temp {int a,b};
3896 procedure P (A,B: In Out ...) is temp P (int A,B)
3897 begin {
3898 .. ..
3899 end P; return {A,B};
3900 }
3902 temp t;
3903 P(X,Y); t = P(X,Y);
3904 X = t.a , Y = t.b;
3906 For subprogram types we need to perform mainly the same conversions to
3907 GCC form that are needed for procedures and function declarations. The
3908 only difference is that at the end, we make a type declaration instead
3909 of a function declaration. */
3914 {
3915 tree gnu_ext_name
3917 const enum inline_status_t inline_status
3920 /* Subprograms marked both Intrinsic and Always_Inline need not
3921 have a body of their own. */
3922 bool extern_flag
3924 || imported_p
3927 tree gnu_param_list;
3929 /* A parameter may refer to this type, so defer completion of any
3930 incomplete types. */
3932 {
3933 defer_incomplete_level++;
3935 }
3937 /* If the subprogram has an alias, it is probably inherited, so
3938 we can use the original one. If the original "subprogram"
3939 is actually an enumeration literal, it may be the first use
3940 of its type, so we must elaborate that type now. */
3942 {
3950 /* Elaborate any itypes in the parameters of this entity. */
3957 /* Materialize renamed subprograms in the debugging information
3958 when the renamed object is known at compile time; we consider
3959 such renamings as imported declarations.
3961 Because the parameters in generic instantiations are generally
3962 materialized as renamings, we often end up having both the
3963 renamed subprogram and the renaming in the same context and with
3964 the same name; in this case, renaming is both useless debug-wise
3965 and potentially harmful as name resolution in the debugger could
3966 return twice the same entity! So avoid this case. */
3968 && !artificial_p
3975 {
3980 }
3983 }
3985 /* Get the GCC tree for the (underlying) subprogram type. If the
3986 entity is an actual subprogram, also get the parameter list. */
3987 gnu_type
3991 {
3995 }
3997 /* Deal with platform-specific calling conventions. */
3999 prepend_one_attribute
4002 gnat_entity);
4004 /* If we should request stack realignment for a foreign convention
4005 subprogram, do so. Note that this applies to task entry points
4006 in particular. */
4008 prepend_one_attribute
4011 gnat_entity);
4013 /* Deal with a pragma Linker_Section on a subprogram. */
4019 /* If we are defining the subprogram and it has an Address clause
4020 we must get the address expression from the saved GCC tree for the
4021 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4022 the address expression here since the front-end has guaranteed
4023 in that case that the elaboration has no effects. If there is
4024 an Address clause and we are not defining the object, just
4025 make it a constant. */
4027 {
4031 gnu_address
4038 /* Convert the type of the object to a reference type that can
4039 alias everything as per RM 13.3(19). */
4040 gnu_type
4045 gnu_decl
4051 }
4053 /* If this is a mere subprogram type, just create the declaration. */
4055 {
4058 gnu_decl
4061 }
4063 /* Otherwise create the subprogram declaration with the external name,
4064 the type and the parameter list. However, if this a reference to
4065 the allocation routines, reuse the canonical declaration nodes as
4066 they come with special properties. */
4067 else
4068 {
4073 else
4074 {
4075 gnu_decl
4080 debug_info_p,
4082 gnat_entity);
4086 }
4087 }
4088 }
4099 {
4100 const bool is_from_limited_with
4102 /* Get the "full view" of this entity. If this is an incomplete
4103 entity from a limited with, treat its non-limited view as the
4104 full view. Otherwise, use either the full view or the underlying
4105 full view, whichever is present. This is used in all the tests
4106 below. */
4107 const Entity_Id full_view
4108 = is_from_limited_with
4116 /* If this is an incomplete type with no full view, it must be a Taft
4117 Amendment type or an incomplete type coming from a limited context,
4118 in which cases we return a dummy type. Otherwise, we just get the
4119 type from its Etype. */
4121 {
4123 {
4126 }
4127 else
4128 {
4129 gnu_decl
4132 }
4133 }
4135 /* Or else, if we already made a type for the full view, reuse it. */
4139 /* Or else, if we are not defining the type or there is no freeze
4140 node on it, get the type for the full view. Likewise if this is
4141 a limited_with'ed type not declared in the main unit, which can
4142 happen for incomplete formal types instantiated on a type coming
4143 from a limited_with clause. */
4146 || (is_from_limited_with
4148 {
4151 }
4153 /* Otherwise, make a dummy type entry which will be replaced later.
4154 Save it as the full declaration's type so we can do any needed
4155 updates when we see it. */
4156 else
4157 {
4163 }
4164 }
4168 /* Class-wide types are always transformed into their root type. */
4177 /* If we are just annotating types and have no equivalent record type,
4178 just return void_type, except for root types that have discriminants
4179 because the discriminants will very likely be used in the declarative
4180 part of the associated body so they need to be translated. */
4182 {
4186 {
4188 Entity_Id gnat_field;
4190 /* This is a minimal version of the E_Record_Type handling. */
4197 {
4198 tree gnu_field
4210 }
4214 }
4215 else
4217 }
4219 /* Concurrent types are always transformed into their record type. */
4220 else
4231 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4232 we've already saved it, so we don't try to. */
4238 /* This is a SPARK annotation that only reaches here when compiling in
4239 ASIS mode. */
4247 }
4249 /* If we had a case where we evaluated another type and it might have
4250 defined this one, handle it here. */
4252 {
4255 }
4257 /* If we are processing a type and there is either no DECL for it or
4258 we just made one, do some common processing for the type, such as
4259 handling alignment and possible padding. */
4261 {
4264 /* Process the attributes, if not already done. Note that the type is
4265 already defined so we cannot pass true for IN_PLACE here. */
4268 /* See if a size was specified, by means of either an Object_Size or
4269 a regular Size clause, and validate it if so.
4271 ??? Don't set the size for a String_Literal since it is either
4272 confirming or we don't handle it properly (if the low bound is
4273 non-constant). */
4275 {
4277 gnu_size
4280 else
4281 gnu_size
4285 }
4287 /* If a size was specified, see if we can make a new type of that size
4288 by rearranging the type, for example from a fat to a thin pointer. */
4290 {
4291 gnu_type
4298 }
4300 /* If the alignment has not already been processed and this is not
4301 an unconstrained array type, see if an alignment is specified.
4302 If not, we pick a default alignment for atomic objects. */
4304 ;
4306 {
4310 /* Warn on suspiciously large alignments. This should catch
4311 errors about the (alignment,byte)/(size,bit) discrepancy. */
4313 {
4314 tree size;
4316 /* If a size was specified, take it into account. Otherwise
4317 use the RM size for records or unions as the type size has
4318 already been adjusted to the alignment. */
4324 else
4327 /* Consider an alignment as suspicious if the alignment/size
4328 ratio is greater or equal to the byte/bit ratio. */
4333 gnat_entity);
4334 }
4335 }
4346 /* See if we need to pad the type. If we did and built a new type,
4347 then create a stripped-down declaration for the original type,
4348 mainly for debugging, unless there was already one. */
4350 {
4358 gnat_entity);
4359 }
4361 /* Now set the RM size of the type. We cannot do it before padding
4362 because we need to accept arbitrary RM sizes on integral types. */
4365 /* Back-annotate the alignment of the type if not already set. */
4367 {
4371 /* If the default alignment of "double" or larger scalar types is
4372 specifically capped and this is not an array with an alignment
4373 clause on the component type, return the cap. */
4375 is_capped_double
4378 is_capped_double
4380 else
4385 else
4389 }
4391 /* Likewise for the size, if any. */
4393 {
4396 /* If the size is self-referential, annotate the maximum value
4397 after saturating it, if need be, to avoid a No_Uint value. */
4399 {
4400 const unsigned int align
4402 gnu_size
4404 }
4406 /* If we are just annotating types and the type is tagged, the tag
4407 and the parent components are not generated by the front-end so
4408 alignment and sizes must be adjusted. */
4410 {
4412 const Entity_Id gnat_parent
4414 const unsigned int inherited_align
4415 = derived_p
4418 const unsigned int align
4423 /* If there is neither size clause nor representation clause, the
4424 sizes need to be adjusted. */
4429 {
4430 tree offset
4431 = derived_p
4435 offset
4438 }
4440 gnu_size
4444 /* Tagged types are Strict_Alignment so RM_Size = Esize. */
4447 }
4449 /* Otherwise no adjustment is needed. */
4450 else
4452 }
4454 /* Likewise for the RM size, if any. */
4458 /* If we are at global level, GCC will have applied variable_size to
4459 the type, but that won't have done anything. So, if it's not
4460 a constant or self-referential, call elaborate_expression_1 to
4461 make a variable for the size rather than calculating it each time.
4462 Handle both the RM size and the actual size. */
4467 {
4474 /* ??? For now, store the size as a multiple of the alignment in
4475 bytes so that we can see the alignment from the tree. */
4481 /* ??? gnu_type may come from an existing type so the MULT_EXPR node
4482 may not be marked by the call to create_type_decl below. */
4486 {
4491 {
4495 /* If the position of the variant part is constant, subtract
4496 it from the size of the type of the parent to get the new
4497 size. This manual CSE reduces the data size. */
4499 {
4507 }
4508 else
4509 {
4515 /* ??? For now, store the size as a multiple of the
4516 alignment in bytes so that we can see the alignment
4517 from the tree. */
4524 /* ??? For now, store the offset as a multiple of the
4525 alignment in bytes so that we can see the alignment
4526 from the tree. */
4530 DECL_OFFSET_ALIGN
4532 }
4536 }
4540 else
4541 ada_size
4545 }
4546 }
4548 /* Similarly, if this is a record type or subtype at global level, call
4549 elaborate_expression_2 on any field position. Skip any fields that
4550 we haven't made trees for to avoid problems with class-wide types. */
4555 {
4558 /* ??? For now, store the offset as a multiple of the alignment
4559 in bytes so that we can see the alignment from the tree. */
4562 {
4569 /* ??? The context of gnu_field is not necessarily gnu_type
4570 so the MULT_EXPR node built above may not be marked by
4571 the call to create_type_decl below. */
4573 }
4574 }
4576 /* Now check if the type allows atomic access. */
4580 /* If this is not an unconstrained array type, set some flags. */
4582 {
4583 /* Record the property that objects of tagged types are guaranteed to
4584 be properly aligned. This is necessary because conversions to the
4585 class-wide type are translated into conversions to the root type,
4586 which can be less aligned than some of its derived types. */
4591 /* Record whether the type is passed by reference. */
4595 /* Record whether an alignment clause was specified. */
4599 /* Record whether a pragma Universal_Aliasing was specified. */
4603 /* If it is passed by reference, force BLKmode to ensure that
4604 objects of this type will always be put in memory. */
4607 }
4609 /* If this is a derived type, relate its alias set to that of its parent
4610 to avoid troubles when a call to an inherited primitive is inlined in
4611 a context where a derived object is accessed. The inlined code works
4612 on the parent view so the resulting code may access the same object
4613 using both the parent and the derived alias sets, which thus have to
4614 conflict. As the same issue arises with component references, the
4615 parent alias set also has to conflict with composite types enclosing
4616 derived components. For instance, if we have:
4618 type D is new T;
4619 type R is record
4620 Component : D;
4621 end record;
4623 we want T to conflict with both D and R, in addition to R being a
4624 superset of D by record/component construction.
4626 One way to achieve this is to perform an alias set copy from the
4627 parent to the derived type. This is not quite appropriate, though,
4628 as we don't want separate derived types to conflict with each other:
4630 type I1 is new Integer;
4631 type I2 is new Integer;
4633 We want I1 and I2 to both conflict with Integer but we do not want
4634 I1 to conflict with I2, and an alias set copy on derivation would
4635 have that effect.
4637 The option chosen is to make the alias set of the derived type a
4638 superset of that of its parent type. It trivially fulfills the
4639 simple requirement for the Integer derivation example above, and
4640 the component case as well by superset transitivity:
4642 superset superset
4643 R ----------> D ----------> T
4645 However, for composite types, conversions between derived types are
4646 translated into VIEW_CONVERT_EXPRs so a sequence like:
4648 type Comp1 is new Comp;
4649 type Comp2 is new Comp;
4650 procedure Proc (C : Comp1);
4652 C : Comp2;
4653 Proc (Comp1 (C));
4655 is translated into:
4657 C : Comp2;
4658 Proc ((Comp1 &) &VIEW_CONVERT_EXPR <Comp1> (C));
4660 and gimplified into:
4662 C : Comp2;
4663 Comp1 *C.0;
4664 C.0 = (Comp1 *) &C;
4665 Proc (C.0);
4667 i.e. generates code involving type punning. Therefore, Comp1 needs
4668 to conflict with Comp2 and an alias set copy is required.
4670 The language rules ensure the parent type is already frozen here. */
4674 {
4676 /* For constrained packed array subtypes, the implementation type is
4677 used instead of the nominal type. */
4685 }
4687 /* Finally get to the appropriate variant, except for the implementation
4688 type of a packed array because the GNU type might be further adjusted
4689 when the original array type is itself processed. */
4692 {
4693 const int quals
4694 = TYPE_QUAL_VOLATILE
4696 /* This is required by free_lang_data_in_type to disable the ODR. */
4701 }
4703 /* If we already made a decl, just set the type, otherwise create it. */
4705 {
4708 }
4709 else
4712 }
4714 /* Otherwise, for a type reusing an existing DECL, back-annotate values. */
4718 {
4725 }
4727 /* If we haven't already, associate the ..._DECL node that we just made with
4728 the input GNAT entity node. */
4732 /* Now we are sure gnat_entity has a corresponding ..._DECL node,
4733 eliminate as many deferred computations as possible. */
4736 /* If this is an enumeration or floating-point type, we were not able to set
4737 the bounds since they refer to the type. These are always static. */
4740 {
4744 /* If this is a padded type, we need to use the underlying type. */
4748 /* If this is a floating point type and we haven't set a floating
4749 point type yet, use this in the evaluation of the bounds. */
4757 {
4758 /* Enumeration types have specific RM bounds. */
4761 }
4762 else
4763 {
4764 /* Floating-point types don't have specific RM bounds. */
4767 }
4768 }
4770 /* If we deferred processing of incomplete types, re-enable it. If there
4771 were no other disables and we have deferred types to process, do so. */
4775 {
4778 /* We are back to level 0 for the deferring of incomplete types.
4779 But processing these incomplete types below may itself require
4780 deferring, so preserve what we have and restart from scratch. */
4785 {
4792 }
4793 }
4795 /* If we are not defining this type, see if it's on one of the lists of
4796 incomplete types. If so, handle the list entry now. */
4798 {
4803 {
4807 }
4813 {
4819 }
4820 }
4823 force_global--;
4825 /* If this is a packed array type whose original array type is itself
4826 an itype without freeze node, make sure the latter is processed. */
4834 }
4836 /* Similar, but if the returned value is a COMPONENT_REF, return the
4837 FIELD_DECL. */
4839 tree
4841 {
4848 }
4850 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
4851 the GCC type corresponding to that entity. */
4853 tree
4855 {
4856 tree gnu_decl;
4858 /* The back end never attempts to annotate generic types. */
4866 }
4868 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
4869 the unpadded version of the GCC type corresponding to that entity. */
4871 tree
4873 {
4880 }
4882 /* Return whether the E_Subprogram_Type/E_Function/E_Procedure GNAT_ENTITY is
4883 a C++ imported method or equivalent.
4885 We use the predicate to find out whether we need to use METHOD_TYPE instead
4886 of FUNCTION_TYPE for GNAT_ENTITY for the sake compatibility with C++. This
4887 in turn determines whether the "thiscall" calling convention is used by the
4888 back-end for GNAT_ENTITY on 32-bit x86/Windows. */
4890 static bool
4892 {
4893 /* A constructor is a method on the C++ side. We deal with it now because
4894 it is declared without the 'this' parameter in the sources and, although
4895 the front-end will create a version with the 'this' parameter for code
4896 generation purposes, we want to return true for both versions. */
4900 /* Check that the subprogram has C++ convention. */
4904 /* And that the type of the first parameter (indirectly) has it too, but
4905 we make an exception for Interfaces because they need not be imported. */
4915 /* This is the main case: a C++ virtual method imported as a primitive
4916 operation of a tagged type. */
4920 /* This is set on the E_Subprogram_Type built for a dispatching call. */
4924 /* A thunk needs to be handled like its associated primitive operation. */
4928 /* Now on to the annoying case: a C++ non-virtual method, imported either
4929 as a non-primitive operation of a tagged type or as a primitive operation
4930 of an untagged type. We cannot reliably differentiate these cases from
4931 their static member or regular function equivalents in Ada, so we ask
4932 the C++ side through the mangled name of the function, as the implicit
4933 'this' parameter is not encoded in the mangled name of a method. */
4935 {
4942 DMGL_GNU_V3
4943 | DMGL_TYPES
4944 | DMGL_PARAMS
4950 /* We need to release MEM once we have a successful demangling. */
4957 {
4958 /* Make sure there is at least one parameter in C++ too. */
4960 {
4963 n_ada_args++;
4969 n_cpp_args++;
4975 }
4976 else
4978 }
4983 }
4986 }
4988 /* Return the inlining status of the GNAT subprogram SUBPROG. */
4990 static enum inline_status_t
4992 {
5000 {
5001 tree gnu_type;
5003 /* This is a kludge to work around a pass ordering issue: for small
5004 record types with many components, i.e. typically bit-fields, the
5005 initialization routine can contain many assignments that will be
5006 merged by the GIMPLE store merging pass. But this pass runs very
5007 late in the pipeline, in particular after the inlining decisions
5008 are made, so the inlining heuristics cannot take its outcome into
5009 account. Therefore, we optimistically override the heuristics for
5010 the initialization routine in this case. */
5012 && flag_store_merging
5021 }
5024 }
5026 /* Finalize the processing of From_Limited_With incomplete types. */
5028 void
5030 {
5037 {
5041 {
5046 }
5049 }
5050 }
5052 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a kind
5053 of type (such E_Task_Type) that has a different type which Gigi uses
5054 for its representation. If the type does not have a special type for
5055 its representation, return GNAT_ENTITY. */
5057 Entity_Id
5059 {
5066 {
5101 }
5104 }
5106 /* Return a GCC tree for a type corresponding to the component type of the
5107 array type or subtype GNAT_ARRAY. DEFINITION is true if this component
5108 is for an array being defined. DEBUG_INFO_P is true if we need to write
5109 debug information for other types that we may create in the process. */
5111 static tree
5114 {
5118 tree gnu_comp_size;
5122 /* If an alignment is specified, use it as a cap on the component type
5123 so that it can be honored for the whole type, but ignore it for the
5124 original type of packed array types. */
5128 else
5131 /* Try to get a packable form of the component if needed. */
5133 && !is_bit_packed
5139 {
5142 }
5143 else
5146 /* Get and validate any specified Component_Size. */
5147 gnu_comp_size
5152 /* If the component type is a RECORD_TYPE that has a self-referential size,
5153 then use the maximum size for the component size. */
5159 /* If the array has aliased components and the component size is zero, force
5160 the unit size to ensure that the components have distinct addresses. */
5166 /* Honor the component size. This is not needed for bit-packed arrays. */
5168 {
5175 else
5178 /* We need to make sure that the size is a multiple of the alignment.
5179 But we do not misalign the component type because of the alignment
5180 of the array type here; this either must have been done earlier in
5181 the packed case or should be rejected in the non-packed case. */
5183 {
5188 }
5189 else
5195 /* If a padding record was made, declare it now since it will never be
5196 declared otherwise. This is necessary to ensure that its subtrees
5197 are properly marked. */
5200 gnat_array);
5201 }
5203 /* This is a very special case where the array has aliased components and the
5204 component size might be zero at run time. As explained above, we force at
5205 least the unit size but we don't want to build a distinct padding type for
5206 each invocation (they are not canonicalized if they have variable size) so
5207 we cache this special padding type as TYPE_PADDING_FOR_COMPONENT. */
5211 {
5214 else
5215 {
5216 gnu_comp_size
5223 gnat_array);
5224 }
5225 }
5227 /* Now check if the type of the component allows atomic access. */
5231 /* If the component type is a padded type made for a non-bit-packed array
5232 of scalars with reverse storage order, we need to propagate the reverse
5233 storage order to the padding type since it is the innermost enclosing
5234 aggregate type around the scalar. */
5236 && !is_bit_packed
5242 {
5243 const int quals
5244 = TYPE_QUAL_VOLATILE
5247 }
5250 }
5252 /* Return whether TYPE requires that formal parameters of TYPE be initialized
5253 when they are Out parameters passed by copy.
5255 This just implements the set of conditions listed in RM 6.4.1(12). */
5257 static bool
5259 {
5276 {
5284 }
5287 }
5289 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM, to be placed
5290 in the parameter list of GNAT_SUBPROG. GNU_PARAM_TYPE is the GCC tree for
5291 the type of the parameter. FIRST is true if this is the first parameter in
5292 the list of GNAT_SUBPROG. Also set CICO to true if the parameter must use
5293 the copy-in copy-out implementation mechanism.
5295 The returned tree is a PARM_DECL, except for the cases where no parameter
5296 needs to be actually passed to the subprogram; the type of this "shadow"
5297 parameter is then returned instead. */
5299 static tree
5302 {
5307 /* The parameter can be indirectly modified if its address is taken. */
5314 tree gnu_param;
5316 /* Make sure to use the proper SLOC for vector ABI warnings. */
5320 /* Builtins are expanded inline and there is no real call sequence involved.
5321 So the type expected by the underlying expander is always the type of the
5322 argument "as is". */
5327 /* Handle the first parameter of a valued procedure specially: it's a copy
5328 mechanism for which the parameter is never allocated. */
5330 {
5334 }
5336 /* Or else, see if a Mechanism was supplied that forced this parameter
5337 to be passed one way or another. */
5339 forced_by_ref
5341 && !foreign
5345 /* Positive mechanism means by copy for sufficiently small parameters. */
5347 {
5352 else
5354 }
5356 /* Otherwise, it's an unsupported mechanism so error out. */
5357 else
5358 {
5361 }
5363 /* If this is either a foreign function or if the underlying type won't
5364 be passed by reference and is as aligned as the original type, strip
5365 off possible padding type. */
5367 {
5376 }
5378 /* For foreign conventions, pass arrays as pointers to the element type.
5379 First check for unconstrained array and get the underlying array. */
5381 gnu_param_type
5384 /* Arrays are passed as pointers to element type for foreign conventions. */
5386 {
5387 /* Strip off any multi-dimensional entries, then strip
5388 off the last array to get the component type. */
5396 }
5398 /* Fat pointers are passed as thin pointers for foreign conventions. */
5400 gnu_param_type
5403 /* Use a pointer type for the "this" pointer of C++ constructors. */
5405 {
5409 }
5411 /* If we were requested or muss pass by reference, do so.
5412 If we were requested to pass by copy, do so.
5413 Otherwise, for foreign conventions, pass In Out or Out parameters
5414 or aggregates by reference. For COBOL and Fortran, pass all
5415 integer and FP types that way too. For Convention Ada, use
5416 the standard Ada default. */
5420 && ((foreign
5422 || (foreign
5427 || (!foreign
5429 {
5430 /* We take advantage of 6.2(12) by considering that references built for
5431 parameters whose type isn't by-ref and for which the mechanism hasn't
5432 been forced to by-ref allow only a restricted form of aliasing. */
5433 restricted_aliasing_p
5437 }
5439 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
5448 /* If this is an Out parameter that isn't passed by reference and whose
5449 type doesn't require the initialization of formals, we don't make a
5450 PARM_DECL for it. Instead, it will be a VAR_DECL created when we
5451 process the procedure, so just return its type here. Likewise for
5452 the _Init parameter of an initialization procedure or the special
5453 parameter of a valued procedure, never pass them in. */
5455 && !by_ref
5456 && !by_component_ptr
5460 {
5463 }
5476 /* If no Mechanism was specified, indicate what we're using, then
5477 back-annotate it. */
5483 }
5485 /* Associate GNAT_SUBPROG with GNU_TYPE, which must be a dummy type, so that
5486 GNAT_SUBPROG is updated when GNU_TYPE is completed.
5488 Ada 2012 (AI05-019) says that freezing a subprogram does not always freeze
5489 the corresponding profile, which means that, by the time the freeze node
5490 of the subprogram is encountered, types involved in its profile may still
5491 be not yet frozen. That's why we need to update GNAT_SUBPROG when we see
5492 the freeze node of types involved in its profile, either types of formal
5493 parameters or the return type. */
5495 static void
5497 {
5505 {
5510 }
5512 /* Even if there is already a slot for GNU_TYPE, we need to set the flag
5513 because the vector might have been just emptied by update_profiles_with.
5514 This can happen when there are 2 freeze nodes associated with different
5515 views of the same type; the type will be really complete only after the
5516 second freeze node is encountered. */
5521 /* Make sure GNAT_SUBPROG is not associated twice with the same dummy type,
5522 since this would mean updating twice its profile. */
5524 {
5528 /* Entity_Id is a simple integer so we can implement a stable order on
5529 the vector with an ordered insertion scheme and binary search. */
5531 {
5538 else
5540 }
5542 /* l == u and therefore is the insertion point. */
5544 }
5545 else
5549 }
5551 /* Update the GCC tree previously built for the profile of GNAT_SUBPROG. */
5553 static void
5555 {
5556 tree gnu_param_list;
5561 {
5562 /* Builtins cannot have their address taken so we can reset them. */
5567 }
5573 /* If GNAT_SUBPROG is an actual subprogram, GNU_SUBPROG is a FUNCTION_DECL
5574 and needs to be adjusted too. */
5576 {
5578 tree gnu_ext_name
5583 }
5584 }
5586 /* Update the GCC trees previously built for the profiles involving GNU_TYPE,
5587 a dummy type which appears in profiles. */
5589 void
5591 {
5599 /* The flag needs to be reset before calling update_profile, in case
5600 associate_subprog_with_dummy_type is again invoked on GNU_TYPE. */
5609 }
5611 /* Return the GCC tree for GNAT_TYPE present in the profile of a subprogram.
5613 Ada 2012 (AI05-0151) says that incomplete types coming from a limited
5614 context may now appear as parameter and result types. As a consequence,
5615 we may need to defer their translation until after a freeze node is seen
5616 or to the end of the current unit. We also aim at handling temporarily
5617 incomplete types created by the usual delayed elaboration scheme. */
5619 static tree
5621 {
5622 /* This is the same logic as the E_Access_Type case of gnat_to_gnu_entity
5623 so the rationale is exposed in that place. These processings probably
5624 ought to be merged at some point. */
5626 const bool is_from_limited_with
5629 Entity_Id gnat_full_direct_first
5630 = (is_from_limited_with
5634 Entity_Id gnat_full_direct
5635 = ((is_from_limited_with
5643 tree gnu_type;
5649 && ((!in_main_unit
5656 {
5660 {
5667 }
5668 }
5673 else
5676 /* Access-to-unconstrained-array types need a special treatment. */
5678 {
5681 }
5684 }
5686 /* Return true if TYPE contains only integral data, recursively if need be. */
5688 static bool
5690 {
5692 {
5707 }
5710 }
5712 /* Return a GCC tree for a subprogram type corresponding to GNAT_SUBPROG.
5713 DEFINITION is true if this is for a subprogram being defined. DEBUG_INFO_P
5714 is true if we need to write debug information for other types that we may
5715 create in the process. Also set PARAM_LIST to the list of parameters.
5716 If GNAT_SUBPROG is bound to a GCC builtin, return the DECL for the builtin
5717 directly instead of its type. */
5719 static tree
5722 {
5727 Entity_Id gnat_param;
5730 tree gnu_return_type;
5733 /* Non-null for subprograms containing parameters passed by copy-in copy-out
5734 (In Out or Out parameters not passed by reference), in which case it is
5735 the list of nodes used to specify the values of the In Out/Out parameters
5736 that are returned as a record upon procedure return. The TREE_PURPOSE of
5737 an element of this list is a FIELD_DECL of the record and the TREE_VALUE
5738 is the PARM_DECL corresponding to that field. This list will be saved in
5739 the TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
5744 /* Although the semantics of "pure" units in Ada essentially match those of
5745 "const" in GNU C, the semantics of the Is_Pure flag in GNAT do not say
5746 anything about access to global memory, that's why it needs to be mapped
5747 to "pure" instead of "const" in GNU C. The property is orthogonal to the
5748 "nothrow" property only if the EH circuitry is explicit in the internal
5749 representation of the middle-end: if we are to completely hide the EH
5750 circuitry from it, we need to declare that calls to pure Ada subprograms
5751 that can throw have side effects, since they can trigger an "abnormal"
5752 transfer of control; therefore they cannot be "pure" in the GCC sense. */
5760 /* Look into the return type and get its associated GCC tree if it is not
5761 void, and then compute various flags for the subprogram type. But make
5762 sure not to do this processing multiple times. */
5769 {
5774 }
5776 else
5777 {
5778 /* For foreign convention subprograms, return System.Address as void *
5779 or equivalent. Note that this comprises GCC builtins. */
5783 else
5786 /* If this function returns by reference, make the actual return type
5787 the reference type and make a note of that. */
5789 {
5792 }
5794 /* If the return type is an unconstrained array type, the return value
5795 will be allocated on the secondary stack so the actual return type
5796 is the fat pointer type. */
5798 {
5801 }
5803 /* This is the same unconstrained array case, but for a dummy type. */
5806 {
5809 }
5811 /* Likewise, if the return type requires a transient scope, the return
5812 value will also be allocated on the secondary stack so the actual
5813 return type is the reference type. */
5815 {
5818 }
5820 /* If the Mechanism is By_Reference, ensure this function uses the
5821 target's by-invisible-reference mechanism, which may not be the
5822 same as above (e.g. it might be passing an extra parameter). */
5826 /* Likewise, if the return type is itself By_Reference. */
5830 /* If the type is a padded type and the underlying type would not be
5831 passed by reference or the function has a foreign convention, return
5832 the underlying type. */
5834 && (!default_pass_by_ref
5839 /* If the return type is unconstrained, it must have a maximum size.
5840 Use the padded type as the effective return type. And ensure the
5841 function uses the target's by-invisible-reference mechanism to
5842 avoid copying too much data when it returns. */
5844 {
5848 /* If the size overflows to 0, set it to an arbitrary positive
5849 value so that assignments in the type are preserved. Their
5850 actual size is independent of this positive value. */
5854 {
5857 }
5863 /* Declare it now since it will never be declared otherwise. This
5864 is necessary to ensure that its subtrees are properly marked. */
5871 }
5873 /* If the return type has a size that overflows, we usually cannot have
5874 a function that returns that type. This usage doesn't really make
5875 sense anyway, so issue an error here. */
5880 {
5885 }
5887 /* If the return type is incomplete, there are 2 cases: if the function
5888 returns by reference, then the return type is only linked indirectly
5889 in the profile, so the profile can be seen as complete since it need
5890 not be further modified, only the reference types need be adjusted;
5891 otherwise the profile is incomplete and need be adjusted too. */
5893 {
5896 }
5900 || return_by_direct_ref_p
5901 || return_by_invisi_ref_p
5903 }
5905 /* A procedure (something that doesn't return anything) shouldn't be
5906 considered pure since there would be no reason for calling such a
5907 subprogram. Note that procedures with Out (or In Out) parameters
5908 have already been converted into a function with a return type.
5909 Similarly, if the function returns an unconstrained type, then the
5910 function will allocate the return value on the secondary stack and
5911 thus calls to it cannot be CSE'ed, lest the stack be reclaimed. */
5915 /* Loop over the parameters and get their associated GCC tree. While doing
5916 this, build a copy-in copy-out structure if we need one. */
5920 {
5921 const bool mech_is_by_ref
5928 /* For a variadic C function, do not build unnamed parameters. */
5933 /* Fetch an existing parameter with complete type and reuse it. But we
5934 didn't save the CICO property so we can only do it for In parameters
5935 or parameters passed by reference. */
5940 {
5943 }
5945 /* Otherwise translate the parameter type and act accordingly. */
5946 else
5947 {
5950 /* For foreign convention subprograms, pass System.Address as void *
5951 or equivalent. Note that this comprises GCC builtins. */
5955 else
5958 /* If the parameter type is incomplete, there are 2 cases: if it is
5959 passed by reference, then the type is only linked indirectly in
5960 the profile, so the profile can be seen as complete since it need
5961 not be further modified, only the reference type need be adjusted;
5962 otherwise the profile is incomplete and need be adjusted too. */
5964 {
5965 Node_Id gnat_decl;
5969 && TYPE_IS_FAT_POINTER_P
5972 {
5974 gnu_param
5984 }
5986 /* ??? This is a kludge to support null procedures in spec taking
5987 a parameter with an untagged incomplete type coming from a
5988 limited context. The front-end creates a body without knowing
5989 anything about the non-limited view, which is illegal Ada and
5990 cannot be supported. Create a parameter with a fake type. */
5998 else
5999 {
6000 /* Build a minimal PARM_DECL without DECL_ARG_TYPE so that
6001 Call_to_gnu will stop if it encounters the PARM_DECL. */
6002 gnu_param
6004 gnu_param_type);
6006 gnu_param_type);
6008 }
6009 }
6011 /* Otherwise build the parameter declaration normally. */
6012 else
6013 {
6014 gnu_param
6018 /* We are returned either a PARM_DECL or a type if no parameter
6019 needs to be passed; in either case, adjust the type. */
6022 else
6023 {
6026 }
6027 }
6028 }
6030 /* If we have a GCC tree for the parameter, register it. */
6033 {
6034 gnu_param_type_list
6040 /* A pure function in the Ada sense which takes an access parameter
6041 may modify memory through it and thus cannot be considered pure
6042 in the GCC sense, unless it's access-to-function. Likewise it if
6043 takes a by-ref In Out or Out parameter. But if it takes a by-ref
6044 In parameter, then it may only read memory through it and can be
6045 considered pure in the GCC sense. */
6051 }
6053 /* If the parameter uses the copy-in copy-out mechanism, allocate a field
6054 for it in the return type and register the association. */
6056 {
6058 {
6061 /* If this is a function, we also need a field for the
6062 return value to be placed. */
6064 {
6065 tree gnu_field
6067 gnu_return_type,
6073 gnu_cico_list
6077 }
6080 /* Set a default alignment to speed up accesses. But we should
6081 not increase the size of the structure too much, lest it does
6082 not fit in return registers anymore. */
6085 }
6087 tree gnu_field
6098 }
6099 }
6101 /* If the subprogram uses the copy-in copy-out mechanism, possibly adjust
6102 and finish up the return type. */
6104 {
6105 /* If we have a CICO list but it has only one entry, we convert
6106 this function into a function that returns this object. */
6110 /* Do not finalize the return type if the subprogram is stubbed
6111 since structures are incomplete for the back-end. */
6113 {
6118 /* Try to promote the mode if the return type is fully returned
6119 in integer registers, again to speed up accesses. */
6121 && gnu_cico_only_integral_type
6123 NULL_TREE))
6124 {
6125 unsigned int size
6128 scalar_int_mode mode;
6133 {
6141 }
6142 }
6144 /* But demote the mode if the return type is partly returned in FP
6145 registers to avoid creating problematic paradoxical subregs.
6146 Note that we need to cater to historical 32-bit architectures
6147 that incorrectly use the mode to select the return mechanism. */
6149 && !gnu_cico_only_integral_type
6152 NULL_TREE))
6157 }
6160 }
6162 /* The lists have been built in reverse. */
6169 /* Turn imported C++ constructors into their callable form as done in the
6170 front-end, i.e. add the "this" pointer and void the return type. */
6174 {
6175 tree gnu_param_type
6178 tree gnu_param
6180 gnu_param_type);
6181 gnu_param_type_list
6186 }
6188 /* If the profile is incomplete, we only set the (temporary) return and
6189 parameter types; otherwise, we build the full type. In either case,
6190 we reuse an already existing GCC tree that we built previously here. */
6192 {
6194 ;
6195 else
6202 }
6203 else
6204 {
6206 {
6210 {
6214 }
6221 }
6222 else
6223 {
6225 {
6227 gnu_type
6230 }
6231 else
6232 gnu_type
6235 /* GNU_TYPE may be shared since GCC hashes types. Unshare it if it
6236 has a different TYPE_CI_CO_LIST or flags. */
6238 return_unconstrained_p,
6239 return_by_direct_ref_p,
6240 return_by_invisi_ref_p))
6241 {
6247 }
6248 }
6256 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
6257 corresponding DECL node and check the parameter association. */
6260 {
6264 /* If we have a builtin DECL for that function, use it. Check if
6265 the profiles are compatible and warn if they are not. Note that
6266 the checker is expected to post diagnostics in this case. */
6268 {
6269 intrin_binding_t inb
6273 post_error
6275 gnat_subprog);
6278 }
6280 /* Inability to find the builtin DECL most often indicates a genuine
6281 mistake, but imports of unregistered intrinsics are sometimes used
6282 on purpose to allow hooking in alternate bodies; we post a warning
6283 conditioned on Wshadow in this case, to let developers be notified
6284 on demand without risking false positives with common default sets
6285 of options. */
6288 }
6289 }
6294 }
6296 /* Return the external name for GNAT_SUBPROG given its entity name. */
6298 static tree
6300 {
6303 /* If there was no specified Interface_Name and the external and
6304 internal names of the subprogram are the same, only use the
6305 internal name to allow disambiguation of nested subprograms. */
6310 }
6312 /* Set TYPE_NONALIASED_COMPONENT on an array type built by means of
6313 build_nonshared_array_type. */
6315 static void
6317 {
6321 }
6323 /* Set TYPE_REVERSE_STORAGE_ORDER on an array type built by means of
6324 build_nonshared_array_type. */
6326 static void
6328 {
6332 }
6334 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
6336 static bool
6338 {
6345 return
6347 }
6349 /* Return true if the array type GNU_TYPE, which represents a dimension of
6350 GNAT_TYPE, has a non-aliased component in the back-end sense. */
6352 static bool
6354 {
6355 /* If the array type has an aliased component in the front-end sense,
6356 then it also has an aliased component in the back-end sense. */
6360 /* If this is a derived type, then it has a non-aliased component if
6361 and only if its parent type also has one. */
6363 {
6366 gnu_parent_type
6369 }
6371 /* For a multi-dimensional array type, find the component type. */
6376 /* Consider that an array of pointers has an aliased component, which is
6377 sort of logical and helps with Taft Amendment types in LTO mode. */
6381 /* Otherwise, rely exclusively on properties of the element type. */
6383 }
6385 /* Return true if GNAT_ADDRESS is a value known at compile-time. */
6387 static bool
6389 {
6390 /* Handle reference to a constant. */
6393 {
6397 }
6399 /* Catch System'To_Address. */
6404 }
6406 /* Return true if GNAT_RANGE, a N_Range node, cannot be superflat, i.e. if the
6407 inequality HB >= LB-1 is true. LB and HB are the low and high bounds. */
6409 static bool
6411 {
6413 Node_Id scalar_range;
6416 /* If the low bound is not constant, try to find an upper bound. */
6425 /* If the high bound is not constant, try to find a lower bound. */
6434 /* If we have failed to find constant bounds, punt. */
6439 /* We need at least a signed 64-bit type to catch most cases. */
6445 /* If the low bound is the smallest integer, nothing can be smaller. */
6451 }
6453 /* Return true if GNU_EXPR is (essentially) the address of a CONSTRUCTOR. */
6455 static bool
6457 {
6465 }
6467 /* Return true if the size in units represented by GNU_SIZE can be handled by
6468 an allocation. If STATIC_P is true, consider only what can be done with a
6469 static allocation. */
6471 static bool
6473 {
6474 /* We can allocate a fixed size if it is a valid for the middle-end. */
6478 /* We can allocate a variable size if this isn't a static allocation. */
6479 else
6481 }
6483 /* Return true if GNU_EXPR needs a conversion to GNU_TYPE when used as the
6484 initial value of an object of GNU_TYPE. */
6486 static bool
6488 {
6489 /* Do not convert if the object's type is unconstrained because this would
6490 generate useless evaluations of the CONSTRUCTOR to compute the size. */
6495 /* Do not convert if the object's type is a padding record whose field is of
6496 self-referential size because we want to copy only the actual data. */
6500 /* Do not convert a call to a function that returns with variable size since
6501 we want to use the return slot optimization in this case. */
6506 /* Do not convert to a record type with a variant part from a record type
6507 without one, to keep the object simpler. */
6514 /* In all the other cases, convert the expression to the object's type. */
6516 }
6518 /* Add the contribution of [MIN, MAX] to the current number of elements N_ELEM
6519 of an array type and return the result, or NULL_TREE if it overflowed. */
6521 static tree
6523 {
6524 /* First deal with the empty case. */
6533 /* Compute the number of elements in this dimension. */
6534 tree this_n_elem
6540 /* Multiply the current number of elements by the result. */
6547 }
6549 /* Given GNAT_ENTITY, elaborate all expressions that are required to
6550 be elaborated at the point of its definition, but do nothing else. */
6552 void
6554 {
6556 {
6563 {
6567 /* ??? Tests to avoid Constraint_Error in static expressions
6568 are needed until after the front stops generating bogus
6569 conversions on bounds of real types. */
6577 }
6584 {
6585 Node_Id gnat_discriminant_expr;
6586 Entity_Id gnat_field;
6590 gnat_discriminant_expr
6595 /* Ignore access discriminants. */
6600 }
6603 }
6604 }
6606 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
6607 NAME, ARGS and ERROR_POINT. */
6609 static void
6612 tree attr_name,
6613 tree attr_args,
6614 Node_Id attr_error_point)
6615 {
6625 }
6627 /* Prepend to ATTR_LIST an entry for an attribute provided by GNAT_PRAGMA. */
6629 static void
6631 {
6637 /* Map the pragma at hand. Skip if this isn't one we know how to handle. */
6639 {
6670 }
6672 /* See what arguments we have and turn them into GCC trees for attribute
6673 handlers. The first one is always expected to be a string meant to be
6674 turned into an identifier. The next ones are all static expressions,
6675 among which strings meant to be turned into an identifier, except for
6676 a couple of specific attributes that require raw strings. */
6678 {
6683 const bool string_args
6691 {
6695 gnu_arg_list
6698 }
6699 }
6704 }
6706 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
6708 static void
6710 {
6711 Node_Id gnat_temp;
6713 /* Attributes are stored as Representation Item pragmas. */
6719 }
6721 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
6722 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
6723 return the GCC tree to use for that expression. S is the suffix to use
6724 if a variable needs to be created and DEFINITION is true if this is done
6725 for a definition of GNAT_ENTITY. If NEED_VALUE is true, we need a result;
6726 otherwise, we are just elaborating the expression for side-effects. If
6727 NEED_DEBUG is true, we need a variable for debugging purposes even if it
6728 isn't needed for code generation. */
6730 static tree
6733 {
6734 tree gnu_expr;
6736 /* If we already elaborated this expression (e.g. it was involved
6737 in the definition of a private type), use the old value. */
6741 /* If we don't need a value and this is static or a discriminant,
6742 we don't need to do anything. */
6749 /* If it's a static expression, we don't need a variable for debugging. */
6753 /* Otherwise, convert this tree to its GCC equivalent and elaborate it. */
6757 /* Save the expression in case we try to elaborate this entity again. Since
6758 it's not a DECL, don't check it. Don't save if it's a discriminant. */
6763 }
6765 /* Similar, but take a GNU expression and always return a result. */
6767 static tree
6770 {
6775 /* If GNU_EXPR contains a placeholder, just return it. We rely on the fact
6776 that an expression cannot contain both a discriminant and a variable. */
6780 /* If GNU_EXPR is neither a constant nor based on a read-only variable, make
6781 a variable that is initialized to contain the expression when the package
6782 containing the definition is elaborated. If this entity is defined at top
6783 level, replace the expression by the variable; otherwise use a SAVE_EXPR
6784 if this is necessary. */
6787 else
6788 {
6789 /* Skip any conversions and simple constant arithmetics to see if the
6790 expression is based on a read-only variable. */
6798 expr_variable_p
6799 = !(inner
6802 }
6804 /* We only need to use the variable if we are in a global context since GCC
6805 can do the right thing in the local case. However, when not optimizing,
6806 use it for bounds of loop iteration scheme to avoid code duplication. */
6807 use_variable = expr_variable_p
6808 && (expr_global_p
6809 || (!optimize
6810 && definition
6815 /* If the GNAT encodings are not used, we don't need a variable for debug
6816 info purposes if the expression is a constant or another variable, but
6817 we need to be careful because we do not generate debug info for external
6818 variables so DECL_IGNORED_P is not stable across units. */
6822 || (!expr_public_p
6827 /* Now create it, possibly only for debugging purposes. */
6829 {
6830 /* The following variable creation can happen when processing the body
6831 of subprograms that are defined out of the extended main unit and
6832 inlined. In this case, we are not at the global scope, and thus the
6833 new variable must not be tagged "external", as we used to do here as
6834 soon as DEFINITION was false. */
6835 tree gnu_decl
6842 /* Using this variable at debug time (if need_debug is true) requires a
6843 proper location. The back-end will compute a location for this
6844 variable only if the variable is used by the generated code.
6845 Returning the variable ensures the caller will use it in generated
6846 code. Note that there is no need for a location if the debug info
6847 contains an integer constant. */
6850 }
6853 }
6855 /* Similar, but take an alignment factor and make it explicit in the tree. */
6857 static tree
6860 {
6862 return
6865 gnu_expr,
6866 unit_align),
6868 need_debug),
6869 unit_align);
6870 }
6872 /* Structure to hold internal data for elaborate_reference. */
6874 struct er_data
6875 {
6876 Entity_Id entity;
6879 };
6881 /* Wrapper function around elaborate_expression_1 for elaborate_reference. */
6883 static tree
6885 {
6889 /* This is what elaborate_expression_1 does if NEED_DEBUG is false. */
6893 /* If this is a COMPONENT_REF of a fat pointer, elaborate the entire fat
6894 pointer. This may be more efficient, but will also allow us to more
6895 easily find the match for the PLACEHOLDER_EXPR. */
6902 /* If this is the displacement of a pointer, elaborate the pointer and then
6903 displace the result. The actual purpose here is to drop the location on
6904 the expression, which may be problematic if replicated on references. */
6912 return
6914 }
6916 /* Elaborate the reference REF to be used as renamed object for GNAT_ENTITY.
6917 DEFINITION is true if this is done for a definition of GNAT_ENTITY and
6918 INIT is set to the first arm of a COMPOUND_EXPR present in REF, if any. */
6920 static tree
6923 {
6926 }
6928 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
6929 the value passed against the list of choices. */
6931 static tree
6933 {
6942 {
6944 tree gnu_test;
6947 {
6962 /* This represents either a subtype range or a static value of
6963 some kind; Ekind says which. */
6965 {
6971 }
6973 /* ... fall through ... */
6985 }
6987 /* Everything should be folded into constants at this point. */
6997 gnu_test
7008 gnu_test
7011 else
7016 else
7017 gnu_result
7020 }
7023 }
7025 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
7026 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
7028 static int
7030 {
7031 /* If the field contains an array with self-referential size, we'd better
7032 not pack it because this would misalign it and, therefore, cause large
7033 temporaries to be created in case we need to take the address of the
7034 field. See addressable_p and the notes on the addressability issues
7035 for further details. */
7040 /* In the other cases, we can honor the packing. */
7044 /* If the alignment of the record is specified and the field type
7045 is over-aligned, request Storage_Unit alignment for the field. */
7050 /* Likewise if the maximum alignment of the record is specified. */
7056 }
7058 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
7059 placed in GNU_RECORD_TYPE.
7061 PACKED is 1 if the enclosing record is packed or -1 if the enclosing
7062 record has Component_Alignment of Storage_Unit.
7064 DEFINITION is true if this field is for a record being defined.
7066 DEBUG_INFO_P is true if we need to write debug information for types
7067 that we may create in the process. */
7069 static tree
7072 {
7079 const bool is_full_access
7081 const bool is_independent
7083 const bool is_volatile
7087 /* We used to consider that volatile fields also require strict alignment,
7088 but that was an interpolation and would cause us to reject a pragma
7089 volatile on a packed record type containing boolean components, while
7090 there is no basis to do so in the RM. In such cases, the writes will
7091 involve load-modify-store sequences, but that's OK for volatile. The
7092 only constraint is the implementation advice whereby only the bits of
7093 the components should be accessed if they both start and end on byte
7094 boundaries, but that should be guaranteed by the GCC memory model.
7095 Note that we have some redundancies (is_full_access => is_independent,
7096 is_aliased => is_independent and is_by_ref => is_strict_alignment)
7097 so the following formula is sufficient. */
7103 /* Force the type of the Not_Handled_By_Others field to be that of the
7104 field in struct Exception_Data declared in raise.h instead of using
7105 the declared boolean type. We need to do that because there is no
7106 easy way to make use of a C compatible boolean type for the latter. */
7111 /* The qualifier to be used in messages. */
7115 {
7119 else
7121 }
7128 else
7131 /* The message to be used for incompatible size. */
7137 /* If a field requires strict alignment, we cannot pack it (RM 13.2(7)). */
7140 else
7143 /* If a size is specified, use it. Otherwise, if the record type is packed,
7144 use the official RM size. See "Handling of Type'Size Values" in Einfo
7145 for further details. */
7150 {
7154 }
7155 else
7158 /* Likewise for the position. */
7160 {
7163 }
7165 /* If the record has rep clauses and this is the tag field, make a rep
7166 clause for it as well. */
7169 {
7173 }
7175 else
7176 {
7179 }
7181 /* If the field's type is a fixed-size record that does not require strict
7182 alignment, and the record is packed or we have a position specified for
7183 the field that makes it a bitfield or we have a specified size that is
7184 smaller than that of the field's type, then see if we can get either an
7185 integral mode form of the field's type or a smaller form. If we can,
7186 consider that a size was specified for the field if there wasn't one
7187 already, so we know to make it a bitfield and avoid making things wider.
7189 Changing to an integral mode form is useful when the record is packed as
7190 we can then place the field at a non-byte-aligned position and so achieve
7191 tighter packing. This is in addition required if the field shares a byte
7192 with another field and the front-end lets the back-end handle the access
7193 to the field, because GCC cannot handle non-byte-aligned BLKmode fields.
7195 Changing to a smaller form is required if the specified size is smaller
7196 than that of the field's type and the type contains sub-fields that are
7197 padded, in order to avoid generating accesses to these sub-fields that
7198 are wider than the field.
7200 We avoid the transformation if it is not required or potentially useful,
7201 as it might entail an increase of the field's alignment and have ripple
7202 effects on the outer record type. A typical case is a field known to be
7203 byte-aligned and not to share a byte with another field. */
7209 || is_bitfield
7210 || (gnu_size
7212 {
7213 tree gnu_packable_type
7216 {
7220 }
7221 }
7223 /* Now check if the type of the field allows atomic access. */
7225 {
7226 const unsigned int align
7229 gnu_field_type
7233 }
7235 /* If a position is specified, check that it is valid. */
7237 {
7240 /* Ensure the position doesn't overlap with the parent subtype if there
7241 is one. It would be impossible to build CONSTRUCTORs and accessing
7242 the parent could clobber the component in the extension if directly
7243 done. We accept it with -gnatd.K for the sake of compatibility. */
7246 {
7251 post_error_ne_tree
7254 }
7256 /* If this field needs strict alignment, make sure that the record is
7257 sufficiently aligned and that the position and size are consistent
7258 with the type. But don't do it if we are just annotating types and
7259 the field's type is tagged, since tagged types aren't fully laid out
7260 in this mode. Also, note that atomic implies volatile so the inner
7261 test sequences ordering is significant here. */
7264 {
7271 /* If the position is not a multiple of the storage unit, then error
7272 out and reset the position. */
7274 bitsize_unit_node)))
7275 {
7281 }
7283 /* If the position is not a multiple of the alignment of the type,
7284 then error out and reset the position. */
7288 {
7291 field_s);
7298 }
7301 {
7305 /* If the size is not a multiple of the storage unit, then error
7306 out and reset the size. */
7308 bitsize_unit_node)))
7309 {
7315 }
7317 /* If the size is lower than that of the type, or greater for
7318 atomic and aliased, then error out and reset the size. */
7321 {
7325 type_size);
7327 }
7328 }
7329 }
7330 }
7332 else
7333 {
7334 /* If we are packing the record and the field is BLKmode, round the
7335 size up to a byte boundary. */
7338 }
7340 /* We need to make the size the maximum for the type if it is
7341 self-referential and an unconstrained type. In that case, we can't
7342 pack the field since we can't make a copy to align it. */
7344 && !gnu_size
7347 {
7350 }
7352 /* If a size is specified, adjust the field's type to it. */
7354 {
7355 tree orig_field_type;
7357 /* If the field's type is justified modular, we would need to remove
7358 the wrapper to (better) meet the layout requirements. However we
7359 can do so only if the field is not aliased to preserve the unique
7360 layout, if it has the same storage order as the enclosing record
7361 and if the prescribed size is not greater than that of the packed
7362 array to preserve the justification. */
7372 /* Similarly if the field's type is a misaligned integral type, but
7373 there is no restriction on the size as there is no justification. */
7380 gnu_field_type
7384 /* If the type has been extended, we may need to cap the alignment. */
7394 /* If a padding record was made, declare it now since it will never be
7395 declared otherwise. This is necessary to ensure that its subtrees
7396 are properly marked. */
7401 }
7403 /* Otherwise (or if there was an error), don't specify a position. */
7404 else
7407 /* If the field's type is a padded type made for a scalar field of a record
7408 type with reverse storage order, we need to propagate the reverse storage
7409 order to the padding type since it is the innermost enclosing aggregate
7410 type around the scalar. */
7419 /* Now create the decl for the field. */
7420 gnu_field
7427 /* If this is a discriminant, then we treat it specially: first, we set its
7428 index number for the back-annotation; second, we record whether it cannot
7429 be changed once it has been set for the computation of loop invariants;
7430 third, we make it addressable in order for the optimizer to more easily
7431 see that it cannot be modified by assignments to the other fields of the
7432 record (see create_field_decl for a more detailed explanation), which is
7433 crucial to hoist the offset and size computations of dynamic fields. */
7435 {
7441 }
7444 }
7446 /* Return true if at least one member of COMPONENT_LIST needs strict
7447 alignment. */
7449 static bool
7451 {
7452 Node_Id component_decl;
7457 {
7465 }
7468 }
7470 /* Return true if FIELD is an artificial field. */
7472 static bool
7474 {
7475 /* These fields are generated by the front-end proper. */
7479 /* These fields are generated by gigi. */
7484 }
7486 /* Return true if FIELD is a non-artificial field with self-referential
7487 size. */
7489 static bool
7491 {
7499 }
7501 /* Return true if FIELD is a non-artificial field with variable size. */
7503 static bool
7505 {
7513 }
7515 /* qsort comparer for the bit positions of two record components. */
7517 static int
7519 {
7522 const int ret
7526 }
7528 /* Sort the LIST of fields in reverse order of increasing position. */
7530 static tree
7532 {
7542 {
7545 }
7548 }
7550 /* Reverse function from gnat_to_gnu_field: return the GNAT field present in
7551 either GNAT_COMPONENT_LIST or the discriminants of GNAT_RECORD_TYPE, and
7552 corresponding to the GNU tree GNU_FIELD. */
7554 static Entity_Id
7556 Entity_Id gnat_record_type)
7557 {
7565 {
7569 }
7579 }
7581 /* Issue a warning for the problematic placement of GNU_FIELD present in
7582 either GNAT_COMPONENT_LIST or the discriminants of GNAT_RECORD_TYPE.
7583 IN_VARIANT is true if GNAT_COMPONENT_LIST is the list of a variant.
7584 DO_REORDER is true if fields of GNAT_RECORD_TYPE are being reordered. */
7586 static void
7590 {
7594 Entity_Id gnat_field
7599 = in_variant
7611 = do_reorder
7618 }
7620 /* Likewise but for every field present on GNU_FIELD_LIST. */
7622 static void
7626 {
7630 }
7632 /* Structure holding information for a given variant. */
7634 {
7635 /* The record type of the variant. */
7636 tree type;
7638 /* The name of the variant. */
7639 tree name;
7641 /* The qualifier of the variant. */
7642 tree qual;
7644 /* Whether the variant has a rep clause. */
7647 /* Whether the variant is packed. */
7652 /* Translate and chain GNAT_COMPONENT_LIST present in GNAT_RECORD_TYPE to
7653 GNU_FIELD_LIST, set the result as the field list of GNU_RECORD_TYPE and
7654 finish it up. Return true if GNU_RECORD_TYPE has a rep clause that affects
7655 the layout (see below). When called from gnat_to_gnu_entity during the
7656 processing of a record definition, the GCC node for the parent, if any,
7657 will be the single field of GNU_RECORD_TYPE and the GCC nodes for the
7658 discriminants will be on GNU_FIELD_LIST. The other call to this function
7659 is a recursive call for the component list of a variant and, in this case,
7660 GNU_FIELD_LIST is empty. Note that GNAT_COMPONENT_LIST may be Empty.
7662 PACKED is 1 if this is for a packed record or -1 if this is for a record
7663 with Component_Alignment of Storage_Unit.
7665 DEFINITION is true if we are defining this record type.
7667 CANCEL_ALIGNMENT is true if the alignment should be zeroed before laying
7668 out the record. This means the alignment only serves to force fields to
7669 be bitfields, but not to require the record to be that aligned. This is
7670 used for variants.
7672 ALL_REP is true if a rep clause is present for all the fields.
7674 UNCHECKED_UNION is true if we are building this type for a record with a
7675 Pragma Unchecked_Union.
7677 ARTIFICIAL is true if this is a type that was generated by the compiler.
7679 DEBUG_INFO is true if we need to write debug information about the type.
7681 MAYBE_UNUSED is true if this type may be unused in the end; this doesn't
7682 mean that its contents may be unused as well, only the container itself.
7684 FIRST_FREE_POS, if nonzero, is the first (lowest) free field position in
7685 the outer record type down to this variant level. It is nonzero only if
7686 all the fields down to this level have a rep clause and ALL_REP is false.
7688 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
7689 with a rep clause is to be added; in this case, that is all that should
7690 be done with such fields and the return value will be false. */
7692 static bool
7699 {
7700 const bool needs_xv_encodings
7713 /* For each component referenced in a component declaration create a GCC
7714 field and add it to the list, skipping pragmas in the GNAT list. */
7722 {
7726 /* If present, the _Parent field must have been created as the single
7727 field of the record type. Put it before any other fields. */
7729 {
7732 }
7733 else
7734 {
7738 /* If this is the _Tag field, put it before any other fields. */
7742 /* If this is the _Controller field, put it before the other
7743 fields except for the _Tag or _Parent field. */
7745 {
7748 }
7750 /* If this is a regular field, put it after the other fields. */
7751 else
7752 {
7758 /* And record information for the final layout. */
7767 }
7768 }
7771 }
7773 /* At the end of the component list there may be a variant part. */
7776 else
7779 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
7780 mutually exclusive and should go in the same memory. To do this we need
7781 to treat each variant as a record whose elements are created from the
7782 component list for the variant. So here we create the records from the
7783 lists for the variants and put them all into the QUAL_UNION_TYPE.
7784 If this is an Unchecked_Union, we make a UNION_TYPE instead or
7785 use GNU_RECORD_TYPE if there are no fields so far. */
7787 {
7791 tree gnu_var_name
7794 tree gnu_union_name
7796 tree gnu_union_type;
7804 /* Reuse the enclosing union if this is an Unchecked_Union whose fields
7805 are all in the variant part, to match the layout of C unions. There
7806 is an associated check below. */
7809 else
7810 {
7811 gnu_union_type
7819 }
7821 /* If all the fields down to this level have a rep clause, find out
7822 whether all the fields at this level also have one. If so, then
7823 compute the new first free position to be passed downward. */
7826 {
7828 gnu_field;
7831 {
7834 this_first_free_pos
7836 }
7837 else
7838 {
7841 }
7842 }
7844 /* We build the variants in two passes. The bulk of the work is done in
7845 the first pass, that is to say translating the GNAT nodes, building
7846 the container types and computing the associated properties. However
7847 we cannot finish up the container types during this pass because we
7848 don't know where the variant part will be placed until the end. */
7852 {
7857 vinfo_t vinfo;
7865 /* Set the alignment of the inner type in case we need to make
7866 inner objects into bitfields, but then clear it out so the
7867 record actually gets only the alignment required. */
7873 /* Similarly, if the outer record has a size specified and all
7874 the fields have a rep clause, we can propagate the size. */
7876 {
7880 }
7882 /* Add the fields into the record type for the variant. Note that
7883 we aren't sure to really use it at this point, see below. */
7884 has_rep
7890 all_rep || this_first_free_pos
7893 /* Translate the qualifier and annotate the GNAT node. */
7897 /* Deal with packedness like in gnat_to_gnu_field. */
7899 {
7902 }
7903 else
7904 field_packed
7907 /* Push this variant onto the stack for the second pass. */
7915 /* Compute the global properties that will determine the placement of
7916 the variant part. */
7920 }
7922 /* Round up the first free position to the alignment of the variant part
7923 for the variants without rep clause. This will guarantee a consistent
7924 layout independently of the placement of the variant part. */
7928 /* In the second pass, the container types are adjusted if necessary and
7929 finished up, then the corresponding fields of the variant part are
7930 built with their qualifier, unless this is an unchecked union. */
7932 {
7936 /* If this is an Unchecked_Union whose fields are all in the variant
7937 part and we have a single field with no representation clause or
7938 placed at offset zero, use the field directly to match the layout
7939 of C unions. */
7941 && gnu_field_list
7945 {
7948 }
7949 else
7950 {
7951 /* Finalize the variant type now. We used to throw away empty
7952 record types but we no longer do that because we need them to
7953 generate complete debug info for the variant; otherwise, the
7954 union type definition will be lacking the fields associated
7955 with these empty variants. */
7957 {
7958 /* The variant part will be at offset 0 so we need to ensure
7959 that the fields are laid out starting from the first free
7960 position at this level. */
7962 tree gnu_rep_part;
7966 gnu_rep_part
7968 this_first_free_pos);
7973 }
7980 gnu_field
7982 gnu_union_type,
7983 all_rep_and_size
7992 }
7996 }
7998 /* Only make the QUAL_UNION_TYPE if there are non-empty variants. */
8000 {
8004 {
8008 }
8013 /* If GNU_UNION_TYPE is our record type, it means we must have an
8014 Unchecked_Union with no fields. Verify that and, if so, just
8015 return. */
8017 {
8019 && !gnu_field_list
8022 }
8027 /* Deal with packedness like in gnat_to_gnu_field. */
8030 else
8031 union_field_packed
8034 gnu_variant_part
8036 all_rep_and_size
8042 }
8043 }
8045 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they do,
8046 pull them out and put them onto the appropriate list.
8048 Similarly, pull out the fields with zero size and no rep clause, as they
8049 would otherwise modify the layout and thus very likely run afoul of the
8050 Ada semantics, which are different from those of C here.
8052 Finally, if there is an aliased field placed in the list after fields
8053 with self-referential size, pull out the latter in the same way.
8055 Optionally, if the reordering mechanism is enabled, pull out the fields
8056 with self-referential size, variable size and fixed size not a multiple
8057 of a byte, so that they don't cause the regular fields to be either at
8058 self-referential/variable offset or misaligned. Note, in the latter
8059 case, that this can only happen in packed record types so the alignment
8060 is effectively capped to the byte for the whole record. But we don't
8061 do it for packed record types if not all fixed-size fiels can be packed
8062 and for non-packed record types if pragma Optimize_Alignment (Space) is
8063 specified, because this can prevent alignment gaps from being filled.
8065 Optionally, if the layout warning is enabled, keep track of the above 4
8066 different kinds of fields and issue a warning if some of them would be
8067 (or are being) reordered by the reordering mechanism.
8069 ??? If we reorder fields, the debugging information will be affected and
8070 the debugger print fields in a different order from the source code. */
8071 const bool do_reorder
8075 ? has_non_packed_fixed_size_field
8078 const bool w_reorder
8080 && Warn_On_Questionable_Layout
8092 #define MOVE_FROM_FIELD_LIST_TO(LIST) \
8093 do { \
8094 if (gnu_last) \
8095 DECL_CHAIN (gnu_last) = gnu_next; \
8096 else \
8097 gnu_field_list = gnu_next; \
8098 \
8099 DECL_CHAIN (gnu_field) = (LIST); \
8100 (LIST) = gnu_field; \
8101 } while (0)
8105 {
8109 {
8112 }
8115 {
8126 }
8129 {
8132 }
8134 /* We don't need further processing in default mode. */
8136 {
8139 }
8142 {
8144 {
8148 do_reorder);
8149 else
8151 }
8154 {
8157 }
8158 }
8161 {
8163 {
8167 do_reorder);
8168 else
8170 }
8173 {
8176 }
8177 }
8179 else
8180 {
8181 /* If the field has no size, then it cannot be bit-packed. */
8182 const unsigned int bitp_size
8187 /* If the field is bit-packed, we move it to a temporary list that
8188 contains the contiguously preceding bit-packed fields, because
8189 we want to be able to put them back if the misalignment happens
8190 to cancel itself after several bit-packed fields. */
8192 {
8196 {
8199 }
8202 {
8205 }
8206 }
8208 /* No more bit-packed fields, move the existing ones to the end or
8209 put them back at their original location. */
8211 {
8215 {
8217 {
8220 gnat_component_list,
8222 do_reorder);
8223 else
8225 gnat_component_list,
8227 do_reorder);
8228 }
8235 }
8236 else
8237 {
8238 /* Rechain the temporary list in front of GNU_FIELD. */
8241 {
8246 else
8250 }
8251 }
8252 }
8254 else
8256 }
8259 }
8261 #undef MOVE_FROM_FIELD_LIST_TO
8265 /* If permitted, we reorder the fields as follows:
8267 1) all (groups of) fields whose length is fixed and multiple of a byte,
8268 2) the remaining fields whose length is fixed and not multiple of a byte,
8269 3) the remaining fields whose length doesn't depend on discriminants,
8270 4) all fields whose length depends on discriminants,
8271 5) the variant part,
8273 within the record and within each variant recursively. */
8276 {
8277 /* If we have pending bit-packed fields, warn if they would be moved
8278 to after regular fields. */
8282 {
8287 else
8291 }
8292 }
8295 {
8296 /* If we have pending bit-packed fields on the temporary list, we put
8297 them either on the bit-packed list or back on the regular list. */
8299 {
8302 else
8304 }
8306 gnu_field_list
8310 }
8312 /* Otherwise, if there is an aliased field placed after a field whose length
8313 depends on discriminants, we put all the fields of the latter sort, last.
8314 We need to do this in case an object of this record type is mutable. */
8318 /* If P_REP_LIST is nonzero, this means that we are asked to move the fields
8319 in our REP list to the previous level because this level needs them in
8320 order to do a correct layout, i.e. avoid having overlapping fields. */
8324 /* Deal with the case of an extension of a record type with variable size and
8325 partial rep clause, for which the _Parent field is forced at offset 0 and
8326 has variable size. Note that we cannot do it if the field has fixed size
8327 because we rely on the presence of the REP part built below to trigger the
8328 reordering of the fields in a derived record type when all the fields have
8329 a fixed position. */
8333 && !variants_have_rep
8334 && first_free_pos
8337 {
8341 }
8343 /* Otherwise, sort the fields by bit position and put them into their own
8344 record, before the others, if we also have fields without rep clause. */
8346 {
8349 /* If all the fields have a rep clause, we can do a flat layout. */
8350 layout_with_rep = !gnu_field_list
8353 /* Same as above but the extension itself has a rep clause, in which case
8354 we need to set aside the _Parent field to lay out the REP part. */
8356 && !layout_with_rep
8357 && !variants_have_rep
8358 && first_free_pos
8361 {
8364 }
8365 else
8368 gnu_rep_type
8371 /* Sort the fields in order of increasing bit position. */
8377 {
8380 }
8386 {
8390 }
8392 /* Do the layout of the REP part, if any. */
8395 else
8396 {
8403 /* If FIRST_FREE_POS is nonzero, we need to ensure that the fields
8404 without rep clause are laid out starting from this position.
8405 Therefore, we force it as a minimal size on the REP part. */
8406 tree gnu_rep_part
8409 /* If this is an extension, put back the _Parent field as the first
8410 field of the REP part at offset 0 and update its layout. */
8412 {
8418 {
8425 }
8426 }
8431 /* Chain the REP part at the beginning of the field list. */
8434 }
8435 }
8437 /* Chain the variant part at the end of the field list. */
8449 /* Chain the fields with zero size at the beginning of the field list. */
8455 }
8457 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
8458 placed into an Esize, Component_Bit_Offset, or Component_Size value
8459 in the GNAT tree. */
8461 static Uint
8463 {
8465 TCode tcode;
8469 /* See if we've already saved the value for this node. */
8471 {
8479 }
8480 else
8483 /* If we do not return inside this switch, TCODE will be set to the
8484 code to be used in a call to Create_Node. */
8486 {
8488 /* For negative values, build NEGATE_EXPR of the opposite. Such values
8489 can appear for discriminants in expressions for variants. */
8491 {
8495 }
8496 else
8501 /* The only case we handle here is a simple discriminant reference. */
8503 {
8507 /* Climb up the chain of successive extensions, if any. */
8514 {
8515 /* Fall through to common processing as a FIELD_DECL. */
8518 }
8519 else
8521 }
8522 else
8531 CASE_CONVERT:
8535 /* Now just list the operations we handle. */
8563 /* Turn addition of negative constant into subtraction. */
8566 {
8571 }
8573 /* ... fall through ... */
8577 /* Fold conversions from bytes to bits into inner operations. */
8580 {
8584 {
8588 widest_int op1;
8592 else
8593 {
8598 }
8600 }
8601 }
8606 /* For negative values in sizetype, build NEGATE_EXPR of the opposite.
8607 Such values can appear in expressions with aligning patterns. */
8609 {
8613 }
8617 /* In regular mode, inline back only if symbolic annotation is requested
8618 in order to avoid memory explosion on big discriminated record types.
8619 But not in ASIS mode, as symbolic annotation is required for DDA. */
8621 {
8624 }
8625 else
8630 }
8632 /* Now get each of the operands that's relevant for this code. If any
8633 cannot be expressed as a repinfo node, say we can't. */
8636 {
8640 }
8644 /* Save the result in the cache. */
8646 {
8648 /* We can't assume the hash table data hasn't moved since the initial
8649 look up, so we have to search again. Allocating and inserting an
8650 entry at that point would be an alternative, but then we'd better
8651 discard the entry if we decided not to cache it. */
8657 }
8660 }
8662 /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
8663 and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
8664 size and alignment used by Gigi. Prefer SIZE over TYPE_SIZE if non-null.
8665 BY_REF is true if the object is used by reference. */
8667 void
8669 {
8671 {
8674 else
8676 }
8679 {
8688 }
8693 }
8695 /* Return first element of field list whose TREE_PURPOSE is the same as ELEM.
8696 Return NULL_TREE if there is no such element in the list. */
8698 static tree
8700 {
8702 {
8707 }
8709 }
8711 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding GCC type,
8712 set Component_Bit_Offset and Esize of the components to the position and
8713 size used by Gigi. */
8715 static void
8717 {
8718 /* For an extension, the inherited components have not been translated because
8719 they are fetched from the _Parent component on the fly. */
8720 const bool is_extension
8723 /* We operate by first making a list of all fields and their position (we
8724 can get the size easily) and then update all the sizes in the tree. */
8725 tree gnu_list
8736 {
8738 gnu_list);
8740 {
8744 /* If we are just annotating types and the type is tagged, the tag
8745 and the parent components are not generated by the front-end so
8746 we need to add the appropriate offset to each component without
8747 representation clause. */
8751 {
8752 tree parent_bit_offset;
8754 /* For a component appearing in the current extension, the
8755 offset is the size of the parent. */
8758 parent_bit_offset
8760 bitsizetype);
8761 else
8765 parent_bit_offset
8769 offset
8773 parent_bit_offset,
8774 bitsize_unit_node)));
8775 }
8777 /* If the field has a variable offset, also compute the normalized
8778 position since it's easier to do on trees here than to deduce
8779 it from the annotated expression of Component_Bit_Offset. */
8781 {
8787 }
8789 Set_Component_Bit_Offset
8795 }
8797 {
8798 /* If there is no entry, this is an inherited component whose
8799 position is the same as in the parent type. */
8802 /* If we are just annotating types, discriminants renaming those of
8803 the parent have no entry so deal with them specifically. */
8810 {
8815 }
8821 }
8822 }
8823 }
8825 /* Scan all fields in GNU_TYPE and return a TREE_LIST where TREE_PURPOSE is
8826 the FIELD_DECL and TREE_VALUE a TREE_VEC containing the byte position, the
8827 value to be placed into DECL_OFFSET_ALIGN and the bit position. The list
8828 of fields is flattened, except for variant parts if DO_NOT_FLATTEN_VARIANT
8829 is set to true. GNU_POS is to be added to the position, GNU_BITPOS to the
8830 bit position, OFFSET_ALIGN is the present offset alignment. GNU_LIST is a
8831 pre-existing list to be chained to the newly created entries. */
8833 static tree
8836 {
8837 tree gnu_field;
8840 gnu_field;
8842 {
8847 unsigned int our_offset_align
8856 /* Recurse on internal fields, flattening the nested fields except for
8857 those in the variant part, if requested. */
8859 {
8863 gnu_list
8867 else
8868 gnu_list
8872 }
8873 }
8876 }
8878 /* Return a list describing the substitutions needed to reflect the
8879 discriminant substitutions from GNAT_TYPE to GNAT_SUBTYPE. They can
8880 be in any order. The values in an element of the list are in the form
8881 of operands to SUBSTITUTE_IN_EXPR. DEFINITION is true if this is for
8882 a definition of GNAT_SUBTYPE. */
8886 {
8888 Entity_Id gnat_discrim;
8889 Node_Id gnat_constr;
8896 /* Ignore access discriminants. */
8898 {
8900 tree replacement
8904 /* If this is a definition, we need to make sure that the SAVE_EXPRs
8905 are instantiated on every possibly path in size computations. */
8911 }
8914 }
8916 /* Scan all fields in {GNU_QUAL_UNION_TYPE,GNAT_VARIANT_PART} and return a list
8917 describing the variants of GNU_QUAL_UNION_TYPE that are still relevant after
8918 applying the substitutions described in SUBST_LIST. GNU_LIST is an existing
8919 list to be prepended to the newly created entries. */
8924 {
8925 Node_Id gnat_variant;
8926 tree gnu_field;
8929 gnat_variant
8933 gnu_field;
8935 gnat_variant
8939 {
8947 /* If the new qualifier is not unconditionally false, its variant may
8948 still be accessed. */
8950 {
8952 variant_desc v
8957 /* Annotate the GNAT node if present. */
8961 /* Recurse on the variant subpart of the variant, if any. */
8964 gnu_list
8967 ? Variant_Part
8970 subst_list,
8971 gnu_list);
8973 /* If the new qualifier is unconditionally true, the subsequent
8974 variants cannot be accessed. */
8977 }
8978 }
8981 }
8983 /* If SIZE has overflowed, return the maximum valid size, which is the upper
8984 bound of the signed sizetype in bits, rounded down to ALIGN. Otherwise
8985 return SIZE unmodified. */
8987 static tree
8989 {
8991 {
8992 size
8997 }
9000 }
9002 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
9003 corresponding to GNAT_OBJECT. If the size is valid, return an INTEGER_CST
9004 corresponding to its value. Otherwise, return NULL_TREE. KIND is set to
9005 VAR_DECL if we are specifying the size of an object, TYPE_DECL for the
9006 size of a type, and FIELD_DECL for the size of a field. COMPONENT_P is
9007 true if we are being called to process the Component_Size of GNAT_OBJECT;
9008 this is used only for error messages. ZERO_OK is true if a size of zero
9009 is permitted; if ZERO_OK is false, it means that a size of zero should be
9010 treated as an unspecified size. S1 and S2 are used for error messages. */
9012 static tree
9016 {
9017 Node_Id gnat_error_node;
9020 /* Return 0 if no size was specified. */
9024 /* Ignore a negative size since that corresponds to our back-annotation. */
9028 /* Find the node to use for error messages. */
9037 else
9040 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
9041 but cannot be represented in bitsizetype. */
9044 {
9047 gnat_object);
9048 else
9050 gnat_object);
9052 }
9054 /* Ignore a zero size if it is not permitted. */
9058 /* The size of objects is always a multiple of a byte. */
9061 {
9065 else
9069 }
9071 /* If this is an integral type or a bit-packed array type, the front-end has
9072 already verified the size, so we need not do it again (which would mean
9073 checking against the bounds). However, if this is an aliased object, it
9074 may not be smaller than the type of the object. */
9079 /* If the object is a record that contains a template, add the size of the
9080 template to the specified size. */
9087 /* If the old size is self-referential, get the maximum size. */
9091 /* If this is an access type or a fat pointer, the minimum size is that given
9092 by the smallest integral mode that's valid for pointers. */
9094 {
9099 }
9101 /* Issue an error either if the default size of the object isn't a constant
9102 or if the new size is smaller than it. */
9106 {
9111 {
9114 }
9117 else
9122 }
9125 }
9127 /* Similarly, but both validate and process a value of RM size. This routine
9128 is only called for types. */
9130 static void
9132 {
9133 Node_Id gnat_attr_node;
9136 /* Do nothing if no size was specified. */
9140 /* Only issue an error if a Value_Size clause was explicitly given for the
9141 entity; otherwise, we'd be duplicating an error on the Size clause. */
9142 gnat_attr_node
9147 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
9148 but cannot be represented in bitsizetype. */
9151 {
9154 gnat_entity);
9156 }
9158 /* Ignore a zero size unless a Value_Size clause exists, or a size clause
9159 exists, or this is an integer type, in which case the front-end will
9160 have always set it. */
9169 /* If the old size is self-referential, get the maximum size. */
9173 /* Issue an error either if the old size of the object isn't a constant or
9174 if the new size is smaller than it. The front-end has already verified
9175 this for scalar and bit-packed array types. */
9183 {
9185 post_error_ne_tree
9189 }
9191 /* Otherwise, set the RM size proper for integral types... */
9198 /* ...or the Ada size for record and union types. */
9202 }
9204 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
9205 a type or object whose present alignment is ALIGN. If this alignment is
9206 valid, return it. Otherwise, give an error and return ALIGN. */
9208 static unsigned int
9210 {
9213 Node_Id gnat_error_node;
9215 /* Don't worry about checking alignment if alignment was not specified
9216 by the source program and we already posted an error for this entity. */
9220 /* Post the error on the alignment clause if any. Note, for the implicit
9221 base type of an array type, the alignment clause is on the first
9222 subtype. */
9230 gnat_error_node =
9233 else
9236 /* Within GCC, an alignment is an integer, so we must make sure a value is
9237 specified that fits in that range. Also, there is an upper bound to
9238 alignments we can support/allow. */
9246 {
9250 /* If the default alignment of "double" or larger scalar types is
9251 specifically capped and the new alignment is above the cap, do
9252 not post an error and change the alignment only if there is an
9253 alignment clause; this makes it possible to have the associated
9254 GCC type overaligned by default for performance reasons. */
9256 {
9257 Entity_Id gnat_type
9259 is_capped_double
9261 }
9263 {
9264 Entity_Id gnat_type
9266 is_capped_double
9268 }
9269 else
9273 {
9276 }
9277 else
9278 {
9285 }
9286 }
9287 else
9288 {
9292 }
9295 }
9297 /* Promote the alignment of GNU_TYPE corresponding to GNAT_ENTITY. Return
9298 a positive value on success or zero on failure. */
9300 static unsigned int
9302 {
9305 /* No point in promoting the alignment if this doesn't prevent BLKmode access
9306 to the object, in particular block copy, as this will for example disable
9307 the NRV optimization for it. No point in jumping through all the hoops
9308 needed in order to support BIGGEST_ALIGNMENT if we don't really have to.
9309 So we cap to the smallest alignment that corresponds to a known efficient
9310 memory access pattern, except for a full access entity. */
9312 {
9315 }
9316 else
9317 {
9320 }
9322 /* Do the promotion within the above limits. */
9328 else
9331 /* But make sure not to under-align the object. */
9335 /* And honor the minimum valid atomic alignment, if any. */
9336 #ifdef MINIMUM_ATOMIC_ALIGNMENT
9339 #endif
9342 }
9344 /* Verify that TYPE is something we can implement atomically. If not, issue
9345 an error for GNAT_ENTITY. COMPONENT_P is true if we are being called to
9346 process a component type. */
9348 static void
9350 {
9352 Node_Id gnat_node;
9353 machine_mode mode;
9356 tree size;
9358 /* If this is an anonymous base type, nothing to check, the error will be
9359 reported on the source type if need be. */
9368 /* Consider all aligned floating-point types atomic and any aligned types
9369 that are represented by integers no wider than a machine word. */
9370 scalar_int_mode int_mode;
9377 /* For the moment, also allow anything that has an alignment equal to its
9378 size and which is smaller than a word. */
9389 {
9390 unsigned char pragma_id
9395 {
9398 }
9399 }
9407 else
9410 }
9413 /* Helper for the intrin compatibility checks family. Evaluate whether
9414 two types are definitely incompatible. */
9416 static bool
9418 {
9433 {
9440 /* Assume designated types are ok. We'd need to account for char * and
9441 void * variants to do better, which could rapidly get messy and isn't
9442 clearly worth the effort. */
9447 }
9450 }
9452 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
9453 on the Ada/builtin argument lists for the INB binding. */
9455 static bool
9457 {
9463 /* Sequence position of the last argument we checked. */
9467 {
9471 /* If we've exhausted both lists simultaneously, we're done. */
9475 /* If the internal builtin uses a variable list, accept anything. */
9479 /* If we're done with the Ada args and not with the internal builtin
9480 args, or the other way around, complain. */
9483 {
9486 }
9490 {
9494 }
9496 /* Otherwise, check that types match for the current argument. */
9497 argpos ++;
9499 {
9503 }
9508 }
9511 }
9513 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
9514 on the Ada/builtin return values for the INB binding. */
9516 static bool
9518 {
9522 /* Accept function imported as procedure, common and convenient. */
9527 /* Check return types compatibility otherwise. Note that this
9528 handles void/void as well. */
9530 {
9534 }
9537 }
9539 /* Check and return whether the Ada and gcc builtin profiles bound by INB are
9540 compatible. Issue relevant warnings when they are not.
9542 This is intended as a light check to diagnose the most obvious cases, not
9543 as a full fledged type compatibility predicate. It is the programmer's
9544 responsibility to ensure correctness of the Ada declarations in Imports,
9545 especially when binding straight to a compiler internal. */
9547 static bool
9549 {
9550 /* Check compatibility on return values and argument lists, each responsible
9551 for posting warnings as appropriate. Ensure use of the proper sloc for
9552 this purpose. */
9565 }
9567 /* Return a FIELD_DECL node modeled on OLD_FIELD. FIELD_TYPE is its type
9568 and RECORD_TYPE is the type of the parent. If SIZE is nonzero, it is the
9569 specified size for this field. POS_LIST is a position list describing
9570 the layout of OLD_FIELD and SUBST_LIST a substitution list to be applied
9571 to this layout. */
9573 static tree
9577 {
9589 /* If the position is now a constant, we can set it as the position of the
9590 field when we make it. Otherwise, we need to deal with it specially. */
9593 else
9596 new_field
9602 {
9604 /* Finalize the position. */
9613 }
9621 }
9623 /* Create the REP part of RECORD_TYPE with REP_TYPE. If MIN_SIZE is nonzero,
9624 it is the minimal size the REP_PART must have. */
9626 static tree
9628 {
9629 tree field;
9639 }
9641 /* Return the REP part of RECORD_TYPE, if any. Otherwise return NULL. */
9643 static tree
9645 {
9648 /* The REP part is the first field, internal, another record, and its name
9649 starts with an 'R'. */
9657 }
9659 /* Return the variant part of RECORD_TYPE, if any. Otherwise return NULL. */
9661 tree
9663 {
9664 tree field;
9666 /* The variant part is the only internal field that is a qualified union. */
9673 }
9675 /* Return a new variant part modeled on OLD_VARIANT_PART. VARIANT_LIST is
9676 the list of variants to be used and RECORD_TYPE is the type of the parent.
9677 POS_LIST is a position list describing the layout of fields present in
9678 OLD_VARIANT_PART and SUBST_LIST a substitution list to be applied to this
9679 layout. DEBUG_INFO_P is true if we need to write debug information. */
9681 static tree
9687 {
9695 /* First create the type of the variant part from that of the old one. */
9701 /* If the position of the variant part is constant, subtract it from the
9702 size of the type of the parent to get the new size. This manual CSE
9703 reduces the code size when not optimizing. */
9707 {
9717 first_bit));
9720 }
9721 else
9724 /* Now finish up the new variants and populate the union type. */
9726 {
9730 /* Skip variants that don't belong to this nesting level. */
9734 /* Retrieve the list of fields already added to the new variant. */
9738 /* If the old variant had a variant subpart, we need to create a new
9739 variant subpart and add it to the field list. */
9743 {
9744 tree new_variant_subpart
9747 debug_info_p);
9750 }
9752 /* Finish up the new variant and create the field. */
9757 new_field
9765 }
9767 /* Finish up the union type and create the variant part. Note that we don't
9768 reverse the field list because VARIANT_LIST has been traversed in reverse
9769 order. */
9774 new_variant_part
9780 /* With multiple discriminants it is possible for an inner variant to be
9781 statically selected while outer ones are not; in this case, the list
9782 of fields of the inner variant is not flattened and we end up with a
9783 qualified union with a single member. Drop the useless container. */
9785 {
9794 }
9797 }
9799 /* Copy the size (and alignment and alias set) from OLD_TYPE to NEW_TYPE,
9800 which are both RECORD_TYPE, after applying the substitutions described
9801 in SUBST_LIST. */
9803 static void
9806 {
9830 SET_TYPE_ADA_SIZE
9834 /* Finalize the size. */
9837 }
9839 /* Return true if DISC is a stored discriminant of RECORD_TYPE. */
9843 {
9850 else
9852 }
9854 /* Copy the layout from {GNAT,GNU}_OLD_TYPE to {GNAT,GNU}_NEW_TYPE, which are
9855 both record types, after applying the substitutions described in SUBST_LIST.
9856 DEBUG_INFO_P is true if we need to write debug information for NEW_TYPE. */
9858 static void
9860 Entity_Id gnat_old_type,
9861 tree gnu_new_type,
9862 tree gnu_old_type,
9865 {
9872 /* Look for REP and variant parts in the old type. */
9876 /* If there is a variant part, we must compute whether the constraints
9877 statically select a particular variant. If so, we simply drop the
9878 qualified union and flatten the list of fields. Otherwise we will
9879 build a new qualified union for the variants that are still relevant. */
9881 {
9886 gnu_variant_list
9888 is_subtype
9889 ? Empty
9890 : Variant_Part
9892 subst_list,
9893 vNULL);
9895 /* If all the qualifiers are unconditionally true, the innermost variant
9896 is statically selected. */
9900 {
9903 }
9905 /* Otherwise, create the new variants. */
9908 {
9911 tree suffix
9921 }
9922 }
9923 else
9924 {
9927 }
9929 /* Make a list of fields and their position in the old type. */
9930 tree gnu_pos_list
9936 /* Now go down every component in the new type and compute its size and
9937 position from those of the component in the old type and the stored
9938 constraints of the new type. */
9951 {
9961 /* If the type is the same, retrieve the GCC type from the
9962 old field to take into account possible adjustments. */
9965 else
9968 /* If there was a component clause, the field types must be the same
9969 for the old and new types, so copy the data from the old field to
9970 avoid recomputation here. Also if the field is justified modular
9971 and the optimization in gnat_to_gnu_field was applied. */
9977 {
9980 }
9982 /* If the old field was packed and of constant size, we have to get the
9983 old size here as it might differ from what the Etype conveys and the
9984 latter might overlap with the following field. Try to arrange the
9985 type for possible better packing along the way. */
9988 {
9994 }
9996 else
9999 /* If the context of the old field is the old type or its REP part,
10000 put the field directly in the new type; otherwise look up the
10001 context in the variant list and put the field either in the new
10002 type if there is a selected variant or in one new variant. */
10006 else
10007 {
10009 tree rep_part;
10019 else
10020 /* The front-end may pass us zombie components if it fails to
10021 recognize that a constrain statically selects a particular
10022 variant. Discard them. */
10024 }
10026 /* Now create the new field modeled on the old one. */
10027 gnu_field
10033 /* If the context is a variant, put it in the new variant directly. */
10035 {
10037 {
10040 }
10041 else
10042 {
10045 }
10046 }
10048 /* To match the layout crafted in components_to_record, if this is
10049 the _Tag or _Parent field, put it before any other fields. */
10053 /* Similarly, if this is the _Controller field, put it before the
10054 other fields except for the _Tag or _Parent field. */
10056 {
10059 }
10061 /* Otherwise, put it after the other fields. */
10062 else
10063 {
10065 {
10070 }
10071 else
10072 {
10075 }
10076 }
10078 /* For a stored discriminant in a derived type, replace the field. */
10080 {
10083 }
10084 else
10086 }
10088 /* Put the fields with fixed position in order of increasing position. */
10092 /* Put the fields with variable position at the end. */
10096 /* If there is a variant list and no selected variant, we need to create the
10097 nest of variant parts from the old nest. */
10099 {
10103 /* Same processing as above for the fields of each variant. */
10105 {
10112 }
10114 tree new_variant_part
10120 }
10125 /* If NEW_TYPE is a subtype, it inherits all the attributes from OLD_TYPE.
10126 Otherwise sizes and alignment must be computed independently. */
10130 /* Now go through the entities again looking for itypes that we have not yet
10131 elaborated (e.g. Etypes of fields that have Original_Components). */
10140 }
10142 /* Associate to the implementation type of a packed array type specified by
10143 GNU_TYPE, which is the translation of GNAT_ENTITY, the original array type
10144 if it has been translated. This association is a parallel type for GNAT
10145 encodings or a debug type for standard DWARF. Note that for standard DWARF,
10146 we also want to get the original type name and therefore we return it. */
10148 static tree
10150 {
10151 const Entity_Id gnat_original_array_type
10153 tree gnu_original_array_type;
10166 {
10173 }
10174 else
10175 {
10178 }
10179 }
10181 /* Given a type T, a FIELD_DECL F, and a replacement value R, return an
10182 equivalent type with adjusted size expressions where all occurrences
10183 of references to F in a PLACEHOLDER_EXPR have been replaced by R.
10185 The function doesn't update the layout of the type, i.e. it assumes
10186 that the substitution is purely formal. That's why the replacement
10187 value R must itself contain a PLACEHOLDER_EXPR. */
10189 tree
10191 {
10192 tree nt;
10197 {
10203 /* First the domain types of arrays. */
10206 {
10218 SET_TYPE_INDEX_TYPE
10222 }
10224 /* Then the subtypes. */
10227 {
10239 }
10252 /* These should never show up here. */
10256 {
10276 }
10281 {
10283 tree field;
10285 /* Start out with no fields, make new fields, and chain them
10286 in. If we haven't actually changed the type of any field,
10287 discard everything we've done and return the old type. */
10292 {
10297 {
10300 }
10304 {
10307 }
10309 /* Do the substitution inside the qualifier, if any. */
10311 {
10314 {
10317 }
10318 }
10325 }
10335 }
10339 }
10340 }
10342 /* Return the RM size of GNU_TYPE. This is the actual number of bits
10343 needed to represent the object. */
10345 tree
10347 {
10348 /* For integral types, we store the RM size explicitly. */
10352 /* If the type contains a template, return the padded size of the template
10353 plus the RM size of the actual data. */
10356 return
10361 /* For record or union types, we store the size explicitly. */
10367 /* For other types, this is just the size. */
10369 }
10371 /* Return the name to be used for GNAT_ENTITY. If a type, create a
10372 fully-qualified name, possibly with type information encoding.
10373 Otherwise, return the name. */
10377 {
10380 }
10382 tree
10384 {
10387 }
10389 /* Return an identifier representing the external name to be used for
10390 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
10391 and the specified suffix. */
10393 tree
10395 {
10403 /* A variable using the Stdcall convention lives in a DLL. We adjust
10404 its name to use the jump table, the _imp__NAME contains the address
10405 for the NAME variable. */
10408 {
10414 }
10417 }
10419 /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
10420 string, return a new IDENTIFIER_NODE that is the concatenation of
10421 the name followed by "___" and the specified suffix. */
10423 tree
10425 {
10432 }
10434 /* Initialize the data structures of the decl.c module. */
10436 void
10438 {
10439 /* Initialize the cache of annotated values. */
10442 /* Initialize the association of dummy types with subprograms. */
10444 }
10446 /* Destroy the data structures of the decl.c module. */
10448 void
10450 {
10451 /* Destroy the cache of annotated values. */
10455 /* Destroy the association of dummy types with subprograms. */
10458 }