| blob | 494b24e21119c74513fb25913ed3d640089a78cb |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2023, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License along with GCC; see the file COPYING3. If not see *
19 * <http://www.gnu.org/licenses/>. *
20 * *
21 * GNAT was originally developed by the GNAT team at New York University. *
22 * Extensive contributions were provided by Ada Core Technologies Inc. *
23 * *
24 ****************************************************************************/
56 /* The "stdcall" convention is really supported on 32-bit x86/Windows only.
57 The following macro is a helper to avoid having to check for a Windows
58 specific attribute throughout this unit. */
60 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
61 #ifdef TARGET_64BIT
62 #define Has_Stdcall_Convention(E) \
63 (!TARGET_64BIT && Convention (E) == Convention_Stdcall)
64 #else
65 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
66 #endif
67 #else
68 #define Has_Stdcall_Convention(E) 0
69 #endif
73 /* Stack realignment is necessary for functions with foreign conventions when
74 the ABI doesn't mandate as much as what the compiler assumes - that is, up
75 to PREFERRED_STACK_BOUNDARY.
77 Such realignment can be requested with a dedicated function type attribute
78 on the targets that support it. We define FOREIGN_FORCE_REALIGN_STACK to
79 characterize the situations where the attribute should be set. We rely on
80 compiler configuration settings for 'main' to decide. */
82 #ifdef MAIN_STACK_BOUNDARY
83 #define FOREIGN_FORCE_REALIGN_STACK \
84 (MAIN_STACK_BOUNDARY < PREFERRED_STACK_BOUNDARY)
85 #else
86 #define FOREIGN_FORCE_REALIGN_STACK 0
87 #endif
89 /* The largest TYPE_ARRAY_MAX_SIZE value we set on an array type.
90 It's an artibrary limit (256 MB) above which we consider that
91 the allocation is essentially unbounded. */
93 #define TYPE_ARRAY_SIZE_LIMIT (1 << 28)
95 struct incomplete
96 {
98 tree old_type;
99 Entity_Id full_type;
100 };
102 /* These variables are used to defer recursively expanding incomplete types
103 while we are processing a record, an array or a subprogram type. */
107 /* This variable is used to delay expanding types coming from a limited with
108 clause and completed Taft Amendment types until the end of the spec. */
112 tree discriminant;
113 tree replacement;
118 /* The type of the variant. */
119 tree type;
121 /* The associated field. */
122 tree field;
124 /* The value of the qualifier. */
125 tree qual;
127 /* The type of the variant after transformation. */
128 tree new_type;
130 /* The auxiliary data. */
131 tree aux;
135 /* A map used to cache the result of annotate_value. */
137 {
140 {
142 }
146 {
148 }
150 static int
152 {
154 }
155 };
159 /* A map used to associate a dummy type with a list of subprogram entities. */
161 {
164 };
166 void
168 {
169 }
171 void
173 {
175 }
178 {
181 {
183 }
187 {
189 }
191 static int
193 {
195 }
196 };
231 tree *);
259 /* The relevant constituents of a subprogram binding to a GCC builtin. Used
260 to pass around calls performing profile compatibility checks. */
270 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
271 entity, return the equivalent GCC tree for that entity (a ..._DECL node)
272 and associate the ..._DECL node with the input GNAT defining identifier.
274 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
275 initial value (in GCC tree form). This is optional for a variable. For
276 a renamed entity, GNU_EXPR gives the object being renamed.
278 DEFINITION is true if this call is intended for a definition. This is used
279 for separate compilation where it is necessary to know whether an external
280 declaration or a definition must be created if the GCC equivalent was not
281 created previously. */
283 tree
285 {
286 /* The construct that declared the entity. */
288 /* The object that the entity renames, if any. */
290 /* The kind of the entity. */
292 /* True if this is a type. */
294 /* True if this is an artificial entity. */
296 /* True if debug info is requested for this entity. */
298 /* True if this entity is to be considered as imported. */
299 const bool imported_p
301 /* True if this entity has a foreign convention. */
303 /* For a type, contains the equivalent GNAT node to be used in gigi. */
305 /* For a subtype, contains the GNAT node to be used as cloned subtype. */
307 /* Temporary used to walk the GNAT tree. */
308 Entity_Id gnat_temp;
309 /* Contains the GCC DECL node which is equivalent to the input GNAT node.
310 This node will be associated with the GNAT node by calling at the end
311 of the `switch' statement. */
313 /* Contains the GCC type to be used for the GCC node. */
315 /* Contains the GCC size tree to be used for the GCC node. */
317 /* Contains the GCC name to be used for the GCC node. */
318 tree gnu_entity_name;
319 /* True if we have already saved gnu_decl as a GNAT association. This can
320 also be used to purposely avoid making such an association but this use
321 case ought not to be applied to types because it can break the deferral
322 mechanism implemented for access types. */
324 /* True if we incremented defer_incomplete_level. */
326 /* True if we incremented force_global. */
328 /* True if we should check to see if elaborated during processing. */
330 /* True if we made GNU_DECL and its type here. */
332 /* Size and alignment of the GCC node, if meaningful. */
334 /* Contains the list of attributes directly attached to the entity. */
337 /* Since a use of an itype is a definition, process it as such if it is in
338 the main unit, except for E_Access_Subtype because it's actually a use
339 of its base type, and for E_Class_Wide_Subtype with an Equivalent_Type
340 because it's actually a use of the latter type. */
342 && is_type
349 {
350 /* Unless it's for an anonymous access type, whose scope is irrelevant,
351 ensure that we are in a subprogram mentioned in the Scope chain of
352 this entity, our current scope is global, or we encountered a task
353 or entry (where we can't currently accurately check scoping). */
355 || !current_function_decl
357 {
360 }
365 {
378 && (current_function_decl
380 {
383 }
384 }
386 /* This abort means the itype has an incorrect scope, i.e. that its
387 scope does not correspond to the subprogram it is first used in. */
389 }
391 /* If we've already processed this entity, return what we got last time.
392 If we are defining the node, we should not have already processed it.
393 In that case, we will abort below when we try to save a new GCC tree
394 for this object. We also need to handle the case of getting a dummy
395 type when a Full_View exists but be careful so as not to trigger its
396 premature elaboration. Likewise for a cloned subtype without its own
397 freeze node, which typically happens when a generic gets instantiated
398 on an incomplete or private type. */
401 {
410 {
411 gnu_decl
416 }
425 {
426 gnu_decl
431 }
434 }
436 /* If this is a numeric or enumeral type, or an access type, a nonzero Esize
437 must be specified unless it was specified by the programmer. Exceptions
438 are for access-to-protected-subprogram types and all access subtypes, as
439 another GNAT type is used to lay out the GCC type for them, as well as
440 access-to-subprogram types if front-end unnesting is enabled. */
455 /* The RM size must be specified for all discrete and fixed-point types. */
459 /* If we get here, it means we have not yet done anything with this entity.
460 If we are not defining it, it must be a type or an entity that is defined
461 elsewhere or externally, otherwise we should have defined it already.
463 In other words, the failure of this assertion typically arises when a
464 reference to an entity (type or object) is made before its declaration,
465 either directly or by means of a freeze node which is incorrectly placed.
466 This can also happen for an entity referenced out of context, for example
467 a parameter outside of the subprogram where it is declared. GNAT_ENTITY
468 is the N_Defining_Identifier of the entity, the problematic N_Identifier
469 being the argument passed to Identifier_to_gnu in the parent frame.
471 One exception is for an entity, typically an inherited operation, which is
472 a local alias for the parent's operation. It is neither defined, since it
473 is an inherited operation, nor public, since it is declared in the current
474 compilation unit, so we test Is_Public on the Alias entity instead. */
476 || is_type
486 /* Get the name of the entity and set up the line number and filename of
487 the original definition for use in any decl we make. Make sure we do
488 not inherit another source location. */
493 /* For cases when we are not defining (i.e., we are referencing from
494 another compilation unit) public entities, show we are at global level
495 for the purpose of computing scopes. Don't do this for components or
496 discriminants since the relevant test is whether or not the record is
497 being defined. */
505 /* Handle any attributes directly attached to the entity. */
509 /* Do some common processing for types. */
511 {
512 /* Compute the equivalent type to be used in gigi. */
515 /* Machine_Attributes on types are expected to be propagated to
516 subtypes. The corresponding Gigi_Rep_Items are only attached
517 to the first subtype though, so we handle the propagation here. */
524 /* Compute a default value for the size of an elementary type. */
526 {
536 else
541 }
542 }
545 {
548 {
549 /* The GNAT record where the component was defined. */
552 /* If the entity is a discriminant of an extended tagged type used to
553 rename a discriminant of the parent type, return the latter. */
557 {
558 gnu_decl
563 }
565 /* If the entity is an inherited component (in the case of extended
566 tagged record types), just return the original entity, which must
567 be a FIELD_DECL. Likewise for discriminants. If the entity is a
568 non-stored discriminant (in the case of derived untagged record
569 types), return the stored discriminant it renames. */
572 {
573 gnu_decl
576 /* GNU_DECL contains a PLACEHOLDER_EXPR for discriminants. */
580 }
582 /* Otherwise, if we are not defining this and we have no GCC type
583 for the containing record, make one for it. Then we should
584 have made our own equivalent. */
586 {
587 /* ??? If this is in a record whose scope is a protected
588 type and we have an Original_Record_Component, use it.
589 This is a workaround for major problems in protected type
590 handling. */
594 {
595 gnu_decl
599 }
600 else
601 {
604 }
608 }
610 /* Here we have no GCC type and this is a reference rather than a
611 definition. This should never happen. Most likely the cause is
612 reference before declaration in the GNAT tree for gnat_entity. */
614 }
618 {
624 /* All references are supposed to be folded in the front-end. */
630 /* Build a CONST_DECL for debugging purposes exclusively. */
631 gnu_decl
636 }
640 /* Ignore constant definitions already marked with the error node. See
641 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
645 {
648 }
650 /* Ignore deferred constant definitions without address clause since
651 they are processed fully in the front-end. If No_Initialization
652 is set, this is not a deferred constant but a constant whose value
653 is built manually. And constants that are renamings are handled
654 like variables. */
656 && !gnu_expr
660 {
664 }
666 /* If this is a use of a deferred constant without address clause,
667 get its full definition. */
671 {
672 gnu_decl
676 }
678 /* If we have a constant that we are not defining, get the expression it
679 was defined to represent. This is necessary to avoid generating dumb
680 elaboration code in simple cases, and we may throw it away later if it
681 is not a constant. But do not do it for dispatch tables because they
682 are only referenced indirectly and we need to have a consistent view
683 of the exported and of the imported declarations of the tables from
684 external units for them to be properly merged in LTO mode. Moreover
685 simply do not retrieve the expression if it is an allocator because
686 the designated type might still be dummy at this point. Note that we
687 invoke gnat_to_gnu_external and not gnat_to_gnu because the expression
688 may contain N_Expression_With_Actions nodes and thus declarations of
689 objects from other units that we need to discard. Note also that we
690 need to do it even if we are only annotating types, so as to be able
691 to validate representation clauses using constants. */
700 /* ... fall through ... */
706 {
709 /* Always create a variable for volatile objects and variables seen
710 constant but with a Linker_Section pragma. */
711 bool const_flag
723 /* We implement RM 13.3(19) for exported and imported (non-constant)
724 objects by making them volatile. */
725 bool volatile_flag
733 /* We need to translate the renamed object even though we are only
734 referencing the renaming. But it may contain a call for which
735 we'll generate a temporary to hold the return value and which
736 is part of the definition of the renaming, so discard it. */
738 {
742 else
744 }
746 /* Get the type after elaborating the renamed object. */
749 else
752 /* For a debug renaming declaration, build a debug-only entity. */
754 {
755 /* Force a non-null value to make sure the symbol is retained. */
759 integer_minus_one_node));
767 }
769 /* If this is a loop variable, its type should be the base type.
770 This is because the code for processing a loop determines whether
771 a normal loop end test can be done by comparing the bounds of the
772 loop against those of the base type, which is presumed to be the
773 size used for computation. But this is not correct when the size
774 of the subtype is smaller than the type. */
778 /* If this is a simple constant, strip the qualifiers from its type,
779 since the constant represents only its value. */
783 /* Reject non-renamed objects whose type is an unconstrained array or
784 any object whose type is a dummy type or void. */
789 {
792 force_global--;
794 }
796 /* If an alignment is specified, use it if valid. Note that exceptions
797 are objects but don't have an alignment and there is also no point in
798 setting it for an address clause, since the final type of the object
799 will be a reference type. */
806 /* Likewise, if a size is specified, use it if valid. */
808 gnu_size
813 {
814 gnu_type
820 }
822 /* If this object has self-referential size, it must be a record with
823 a default discriminant. We are supposed to allocate an object of
824 the maximum size in this case, unless it is a constant with an
825 initializing expression, in which case we can get the size from
826 that. Note that the resulting size may still be a variable, so
827 this may end up with an indirect allocation. */
830 {
832 {
836 {
837 /* If the initializing expression is itself a constant,
838 despite having a nominal type with self-referential
839 size, we can get the size directly from it. */
841 && TYPE_IS_PADDING_P
845 || DECL_READONLY_ONCE_ELAB
847 {
850 }
851 else
852 {
853 gnu_size
855 gnu_expr);
856 gnu_ada_size
858 gnu_expr);
859 }
860 }
861 }
862 /* We may have no GNU_EXPR because No_Initialization is
863 set even though there's an Expression. */
867 {
868 tree gnu_expr_type
872 }
873 else
874 {
876 /* We can be called on unconstrained arrays in this mode. */
880 }
882 /* If the size isn't constant and we are at global level, call
883 elaborate_expression_1 to make a variable for it rather than
884 calculating it each time. */
888 }
890 /* If the size is zero byte, make it one byte since some linkers have
891 troubles with zero-sized objects. If the object will have a
892 template, that will make it nonzero so don't bother. Also avoid
893 doing that for an object renaming or an object with an address
894 clause, as we would lose useful information on the view size
895 (e.g. for null array slices) and we are not allocating the object
896 here anyway. */
908 /* If this is an object with no specified size and alignment, and
909 if either it is full access or we are not optimizing alignment for
910 space and it is composite and not an exception, an Out parameter
911 or a reference to another object, and the size of its type is a
912 constant, set the alignment to the smallest one which is not
913 smaller than the size, with an appropriate cap. */
923 && !imported_p
929 /* If the object is set to have atomic components, find the component
930 type and validate it.
932 ??? Note that we ignore Has_Volatile_Components on objects; it's
933 not at all clear what to do in that case. */
935 {
944 }
946 /* If this is an aliased object with an unconstrained array nominal
947 subtype, make a type that includes the template. We will either
948 allocate or create a variable of that type, see below. */
952 {
954 gnu_type
956 gnu_type,
959 debug_info_p);
960 }
962 /* ??? If this is an object of CW type initialized to a value, try to
963 ensure that the object is sufficient aligned for this value, but
964 without pessimizing the allocation. This is a kludge necessary
965 because we don't support dynamic alignment. */
972 #ifdef MINIMUM_ATOMIC_ALIGNMENT
973 /* If the size is a constant and no alignment is specified, force
974 the alignment to be the minimum valid atomic alignment. The
975 restriction on constant size avoids problems with variable-size
976 temporaries; if the size is variable, there's no issue with
977 atomic access. Also don't do this for a constant, since it isn't
978 necessary and can interfere with constant replacement. Finally,
979 do not do it for Out parameters since that creates an
980 size inconsistency with In parameters. */
990 #endif
992 /* Do not take into account aliased adjustments or alignment promotions
993 to compute the size of the object. */
996 /* If the object is aliased, of a constrained nominal subtype and its
997 size might be zero at run time, we force at least the unit size. */
1005 /* Make a new type with the desired size and alignment, if needed. */
1007 {
1013 /* If the nominal subtype of the object is unconstrained and its
1014 size is not fixed, compute the Ada size from the Ada size of
1015 the subtype and/or the expression; this will make it possible
1016 for gnat_type_max_size to easily compute a maximum size. */
1020 /* If a padding record was made, declare it now since it will
1021 never be declared otherwise. This is necessary to ensure
1022 that its subtrees are properly marked. */
1026 }
1028 /* Now check if the type of the object allows atomic access. */
1032 /* If this is a renaming, avoid as much as possible to create a new
1033 object. However, in some cases, creating it is required because
1034 renaming can be applied to objects that are not names in Ada.
1035 This processing needs to be applied to the raw expression so as
1036 to make it more likely to rename the underlying object. */
1038 {
1039 /* If the renamed object had padding, strip off the reference to
1040 the inner object and reset our type. */
1043 /* Strip useless conversions around the object. */
1045 {
1048 }
1050 /* Or else, if the renamed object has an unconstrained type with
1051 default discriminant, use the padded type. */
1055 /* If this is a constant renaming stemming from a function call,
1056 treat it as a normal object whose initial value is what is being
1057 renamed. RM 3.3 says that the result of evaluating a function
1058 call is a constant object. Therefore, it can be the inner
1059 object of a constant renaming and the renaming must be fully
1060 instantiated, i.e. it cannot be a reference to (part of) an
1061 existing object. And treat other rvalues the same way. */
1065 /* Expand_Dispatching_Call can prepend a comparison of the tags
1066 before the call to "=". */
1077 /* We need to detect the case where a temporary is created to
1078 hold the return value, since we cannot safely rename it at
1079 top level because it lives only in the elaboration routine.
1080 But, at a lower level, an object initialized by a function
1081 call may be (implicitly) renamed as this temporary by the
1082 front-end and, in this case, we cannot make a copy. */
1086 /* We also need to detect the case where the front-end creates
1087 a dangling 'reference to a function call at top level and
1088 substitutes it in the renaming, for example:
1090 q__b : boolean renames r__f.e (1);
1092 can be rewritten into:
1094 q__R1s : constant q__A2s := r__f'reference;
1095 [...]
1096 q__b : boolean renames q__R1s.all.e (1);
1098 We cannot safely rename the rewritten expression since the
1099 underlying object lives only in the elaboration routine but,
1100 as above, this cannot be done at a lower level. */
1102 && (inner
1107 ;
1109 /* Otherwise, this is an lvalue being renamed, so it needs to be
1110 elaborated as a reference and substituted for the entity. But
1111 this means that we must evaluate the address of the renaming
1112 in the definition case to instantiate the SAVE_EXPRs. */
1113 else
1114 {
1120 gnu_expr
1124 /* No DECL_EXPR might be created so the expression needs to be
1125 marked manually because it will likely be shared. */
1129 /* This assertion will fail if the renamed object isn't aligned
1130 enough as to make it possible to honor the alignment set on
1131 the renaming. */
1133 {
1134 const unsigned int ralign
1139 }
1141 /* The expression might not be a DECL so save it manually. */
1147 /* If this is only a reference to the entity, we are done. */
1151 /* Otherwise, emit the initialization statement, if any. */
1155 /* If it needs to be materialized for debugging purposes, build
1156 the entity as indirect reference to the renamed object. */
1158 {
1171 }
1173 /* Otherwise, instantiate the SAVE_EXPRs if needed. */
1178 }
1179 }
1181 /* If we are defining an aliased object whose nominal subtype is
1182 unconstrained, the object is a record that contains both the
1183 template and the object. If there is an initializer, it will
1184 have already been converted to the right type, but we need to
1185 create the template if there is no initializer. */
1187 && !gnu_expr
1190 /* Beware that padding might have been introduced above. */
1193 == RECORD_TYPE
1194 && TYPE_CONTAINS_TEMPLATE_P
1196 {
1197 tree template_field
1205 NULL_TREE);
1208 }
1210 /* Convert the expression to the type of the object if need be. */
1214 /* If this is a pointer that doesn't have an initializing expression,
1215 initialize it to NULL, unless the object is declared imported as
1216 per RM B.1(24). */
1219 && !gnu_expr
1223 /* If we are defining the object and it has an Address clause, we must
1224 either get the address expression from the saved GCC tree for the
1225 object if it has a Freeze node, or elaborate the address expression
1226 here since the front-end has guaranteed that the elaboration has no
1227 effects in this case. */
1229 {
1238 /* Convert the type of the object to a reference type that can
1239 alias everything as per RM 13.3(19). */
1242 gnu_type
1246 const_flag
1252 /* If this is an aliased object with an unconstrained array nominal
1253 subtype, then it can overlay only another aliased object with an
1254 unconstrained array nominal subtype and compatible template. */
1258 {
1262 /* This is the pattern built for a regular object. */
1267 /* This is the pattern built for an overaligned object. */
1270 == PLUS_EXPR
1273 gnu_address
1278 /* We make an exception for an absolute address but we warn
1279 that there is a descriptor at the start of the object. */
1281 {
1284 gnat_entity);
1287 }
1289 else
1290 {
1293 gnat_entity);
1296 }
1297 }
1299 /* If we don't have an initializing expression for the underlying
1300 variable, the initializing expression for the pointer is the
1301 specified address. Otherwise, we have to make a COMPOUND_EXPR
1302 to assign both the address and the initial value. */
1305 else
1306 gnu_expr
1310 NULL_TREE,
1311 gnu_address),
1312 gnu_expr),
1313 gnu_address);
1314 }
1316 /* If it has an address clause and we are not defining it, mark it
1317 as an indirect object. Likewise for Stdcall objects that are
1318 imported. */
1321 {
1322 /* Convert the type of the object to a reference type that can
1323 alias everything as per RM 13.3(19). */
1326 gnu_type
1333 /* No point in taking the address of an initializing expression
1334 that isn't going to be used. */
1337 /* If it has an address clause whose value is known at compile
1338 time, make the object a CONST_DECL. This will avoid a
1339 useless dereference. */
1341 {
1342 Node_Id gnat_address
1346 {
1349 }
1350 }
1351 }
1353 /* If we are at top level and this object is of variable size,
1354 make the actual type a hidden pointer to the real type and
1355 make the initializer be a memory allocation and initialization.
1356 Likewise for objects we aren't defining (presumed to be
1357 external references from other packages), but there we do
1358 not set up an initialization.
1360 If the object's size overflows, make an allocator too, so that
1361 Storage_Error gets raised. Note that we will never free
1362 such memory, so we presume it never will get allocated. */
1365 || !definition
1367 || (gnu_size
1369 size_binop
1371 bitsize_unit_node)),
1373 || !definition
1375 {
1384 /* In case this was a aliased object whose nominal subtype is
1385 unconstrained, the pointer above will be a thin pointer and
1386 build_allocator will automatically make the template.
1388 If we have a template initializer only (that we made above),
1389 pretend there is none and rely on what build_allocator creates
1390 again anyway. Otherwise (if we have a full initializer), get
1391 the data part and feed that to build_allocator.
1393 If we are elaborating a mutable object, tell build_allocator to
1394 ignore a possibly simpler size from the initializer, if any, as
1395 we must allocate the maximum possible size in this case. */
1397 {
1402 {
1403 gnu_alloc_type
1409 else
1410 gnu_expr
1411 = build_component_ref
1415 }
1420 gnat_entity);
1422 gnu_expr
1425 }
1426 else
1428 }
1430 /* If this object would go into the stack and has an alignment larger
1431 than the largest stack alignment the back-end can honor, resort to
1432 a variable of "aligning type". */
1435 && !imported_p
1436 && !static_flag
1438 {
1439 /* Create the new variable. No need for extra room before the
1440 aligned field as this is in automatic storage. */
1441 tree gnu_new_type
1445 tree gnu_new_var
1450 gnat_entity);
1452 /* Initialize the aligned field if we have an initializer. */
1454 add_stmt_with_node
1456 build_component_ref
1459 gnu_expr),
1460 gnat_entity);
1462 /* And setup this entity as a reference to the aligned field. */
1464 gnu_expr
1465 = build_unary_op
1475 }
1477 /* If this is an aggregate constant initialized to a constant, force it
1478 to be statically allocated. This saves an initialization copy. */
1480 && const_flag
1481 && gnu_expr
1490 /* If this is an aliased object with an unconstrained array nominal
1491 subtype, we make its type a thin reference, i.e. the reference
1492 counterpart of a thin pointer, so it points to the array part.
1493 This is aimed to make it easier for the debugger to decode the
1494 object. Note that we have to do it this late because of the
1495 couple of allocation adjustments that might be made above. */
1499 {
1500 /* In case the object with the template has already been allocated
1501 just above, we have nothing to do here. */
1503 {
1504 /* This variable is a GNAT encoding used by Workbench: let it
1505 go through the debugging information but mark it as
1506 artificial: users are not interested in it. */
1507 tree gnu_unc_var
1523 }
1526 gnu_type
1528 }
1530 /* Convert the expression to the type of the object if need be. */
1534 /* If this name is external or a name was specified, use it, but don't
1535 use the Interface_Name with an address clause (see cd30005). */
1541 /* Deal with a pragma Linker_Section on a constant or variable. */
1547 /* Now create the variable or the constant and set various flags. */
1548 gnu_decl
1554 gnat_entity);
1559 /* If we are defining an Out parameter and optimization isn't enabled,
1560 create a fake PARM_DECL for debugging purposes and make it point to
1561 the VAR_DECL. Suppress debug info for the latter but make sure it
1562 will live in memory so that it can be accessed from within the
1563 debugger through the PARM_DECL. */
1565 && definition
1566 && debug_info_p
1567 && !optimize
1569 {
1576 }
1578 /* If this is a loop parameter, set the corresponding flag. */
1582 /* If this is a constant and we are defining it or it generates a real
1583 symbol at the object level and we are referencing it, we may want
1584 or need to have a true variable to represent it:
1585 - if the constant is public and not overlaid on something else,
1586 - if its address is taken,
1587 - if it is aliased,
1588 - if optimization isn't enabled, for debugging purposes. */
1595 {
1596 tree gnu_corr_var
1605 }
1607 /* If this is a constant, even if we don't need a true variable, we
1608 may need to avoid returning the initializer in every case. That
1609 can happen for the address of a (constant) constructor because,
1610 upon dereferencing it, the constructor will be reinjected in the
1611 tree, which may not be valid in every case; see lvalue_required_p
1612 for more details. */
1616 /* If this is a local variable with non-BLKmode and aggregate type,
1617 and optimization isn't enabled, then force it in memory so that
1618 a register won't be allocated to it with possible subparts left
1619 uninitialized and reaching the register allocator. */
1629 /* Back-annotate Esize and Alignment of the object if not already
1630 known. Note that we pick the values of the type, not those of
1631 the object, to shield ourselves from low-level platform-dependent
1632 adjustments like alignment promotion. This is both consistent with
1633 all the treatment above, where alignment and size are set on the
1634 type of the object and not on the object directly, and makes it
1635 possible to support all confirming representation clauses. */
1637 used_by_ref);
1638 }
1642 /* Return a TYPE_DECL for "void" that we previously made. */
1647 /* A special case: for the types Character and Wide_Character in
1648 Standard, we do not list all the literals. So if the literals
1649 are not specified, make this an integer type. */
1651 {
1654 else
1658 /* Set TYPE_STRING_FLAG for Character and Wide_Character types.
1659 This is needed by the DWARF-2 back-end to distinguish between
1660 unsigned integer types and character types. */
1663 /* This flag is needed by the call just below. */
1667 }
1668 else
1669 {
1670 /* We have a list of enumeral constants in First_Literal. We make a
1671 CONST_DECL for each one and build into GNU_LITERAL_LIST the list
1672 to be placed into TYPE_FIELDS. Each node is itself a TREE_LIST
1673 whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
1674 value of the literal. But when we have a regular boolean type, we
1675 simplify this a little by using a BOOLEAN_TYPE. */
1680 Entity_Id gnat_literal;
1682 /* Boolean types with foreign convention have precision 1. */
1697 {
1698 tree gnu_value
1700 /* Do not generate debug info for individual enumerators. */
1701 tree gnu_literal
1707 gnu_list
1709 }
1714 /* Note that the bounds are updated at the end of this function
1715 to avoid an infinite recursion since they refer to the type. */
1717 }
1721 /* For integer types, just make a signed type the appropriate number
1722 of bits. */
1728 {
1729 /* Small_Value is the scale factor. */
1735 /* When encoded as 1/2**N or 1/10**N, describe the scale factor as a
1736 binary or decimal scale: it is easier to read for humans. */
1740 {
1741 tree base
1743 tree exponent
1746 scale_factor
1748 integer_one_node,
1751 }
1753 /* Use the arbitrary scale factor description. Note that we support
1754 a Small_Value whose magnitude is larger than 64-bit even on 32-bit
1755 platforms, so we unconditionally use a (dummy) 128-bit type. */
1756 else
1757 {
1764 scale_factor
1766 }
1770 }
1774 {
1775 /* Packed Array Impl. Types are supposed to be subtypes only. */
1778 /* For modular types, make the unsigned type of the proper number
1779 of bits and then set up the modulus, if required. */
1782 /* Get the modulus in this type. If the modulus overflows, assume
1783 that this is because it was equal to 2**Esize. Note that there
1784 is no overflow checking done on unsigned types, so we detect the
1785 overflow by looking for a modulus of zero, which is invalid. */
1788 /* If the modulus is not 2**Esize, then this also means that the upper
1789 bound of the type, i.e. modulus - 1, is not maximal, so we create an
1790 extra subtype to carry it and set the modulus on the base type. */
1792 {
1798 gnu_type
1800 gnu_high);
1801 }
1802 }
1814 /* For integral subtypes, we make a new INTEGER_TYPE. Note that we do
1815 not want to call create_range_type since we would like each subtype
1816 node to be distinct. ??? Historically this was in preparation for
1817 when memory aliasing is implemented, but that's obsolete now given
1818 the call to relate_alias_sets below.
1820 The TREE_TYPE field of the INTEGER_TYPE points to the base type;
1821 this fact is used by the arithmetic conversion functions.
1823 We elaborate the Ancestor_Subtype if it is not in the current unit
1824 and one of our bounds is non-static. We do this to ensure consistent
1825 naming in the case where several subtypes share the same bounds, by
1826 elaborating the first such subtype first, thus using its name. */
1835 /* Set the precision to the Esize except for bit-packed arrays. */
1839 /* Boolean types with foreign convention have precision 1. */
1841 {
1847 }
1848 /* First subtypes of Character are treated as Character; otherwise
1849 this should be an unsigned type if the base type is unsigned or
1850 if the lower bound is constant and non-negative or if the type
1851 is biased. However, even if the lower bound is constant and
1852 non-negative, we use a signed type for a subtype with the same
1853 size as its signed base type, because this eliminates useless
1854 conversions to it and gives more leeway to the optimizer; but
1855 this means that we will need to explicitly test for this case
1856 when we change the representation based on the RM size. */
1868 else
1872 SET_TYPE_RM_MIN_VALUE
1875 debug_info_p));
1877 SET_TYPE_RM_MAX_VALUE
1880 debug_info_p));
1886 /* Do the same processing for Character subtypes as for types. */
1889 {
1894 }
1896 /* Inherit our alias set from what we're a subtype of. Subtypes
1897 are not different types and a pointer can designate any instance
1898 within a subtype hierarchy. */
1901 /* One of the above calls might have caused us to be elaborated,
1902 so don't blow up if so. */
1904 {
1907 }
1909 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
1913 discrete_type:
1915 /* We have to handle clauses that under-align the type specially. */
1918 && Present
1921 {
1925 }
1927 /* If the type we are dealing with represents a bit-packed array,
1928 we need to have the bits left justified on big-endian targets
1929 and right justified on little-endian targets. We also need to
1930 ensure that when the value is read (e.g. for comparison of two
1931 such values), we only get the good bits, since the unused bits
1932 are uninitialized. Both goals are accomplished by wrapping up
1933 the modular type in an enclosing record type. */
1935 {
1941 /* Make the original array type a parallel/debug type. */
1943 {
1944 tree gnu_name
1946 gnat_entity);
1949 }
1951 /* Set the RM size before wrapping up the original type. */
1955 /* Create a stripped-down declaration, mainly for debugging. */
1957 gnat_entity);
1959 /* Now save it and build the enclosing record type. */
1969 /* Propagate the alignment of the modular type to the record type,
1970 unless there is an alignment clause that under-aligns the type.
1971 This means that bit-packed arrays are given "ceil" alignment for
1972 their size by default, which may seem counter-intuitive but makes
1973 it possible to overlay them on modular types easily. */
1977 /* Propagate the reverse storage order flag to the record type so
1978 that the required byte swapping is performed when retrieving the
1979 enclosed modular value. */
1985 /* Don't declare the field as addressable since we won't be taking
1986 its address and this would prevent create_field_decl from making
1987 a bitfield. */
1988 gnu_field
1992 /* We will output additional debug info manually below. */
1996 /* Make the original array type a parallel/debug type. Note that
1997 gnat_get_array_descr_info needs a TYPE_IMPL_PACKED_ARRAY_P type
1998 so we use an intermediate step for standard DWARF. */
2000 {
2005 }
2006 }
2008 /* If the type we are dealing with has got a smaller alignment than the
2009 natural one, we need to wrap it up in a record type and misalign the
2010 latter; we reuse the padding machinery for this purpose. */
2012 {
2015 /* Set the RM size before wrapping the type. */
2018 /* Create a stripped-down declaration, mainly for debugging. */
2020 gnat_entity);
2022 gnu_type
2028 }
2033 /* The type of the Low and High bounds can be our type if this is
2034 a type from Standard, so set them at the end of the function. */
2045 /* See the E_Signed_Integer_Subtype case for the rationale. */
2062 SET_TYPE_RM_MIN_VALUE
2065 debug_info_p));
2067 SET_TYPE_RM_MAX_VALUE
2070 debug_info_p));
2072 /* Inherit our alias set from what we're a subtype of, as for
2073 integer subtypes. */
2076 /* One of the above calls might have caused us to be elaborated,
2077 so don't blow up if so. */
2081 /* Array Types and Subtypes
2083 In GNAT unconstrained array types are represented by E_Array_Type and
2084 constrained array types are represented by E_Array_Subtype. They are
2085 translated into UNCONSTRAINED_ARRAY_TYPE and ARRAY_TYPE respectively.
2086 But there are no actual objects of an unconstrained array type; all we
2087 have are pointers to that type. In addition to the type node itself,
2088 4 other types associated with it are built in the process:
2090 1. the array type (suffix XUA) containing the actual data,
2092 2. the template type (suffix XUB) containng the bounds,
2094 3. the fat pointer type (suffix XUP) representing a pointer or a
2095 reference to the unconstrained array type:
2096 XUP = struct { XUA *, XUB * }
2098 4. the object record type (suffix XUT) containing bounds and data:
2099 XUT = struct { XUB, XUA }
2101 The bounds of the array type XUA (de)reference the XUB * field of a
2102 PLACEHOLDER_EXPR for the fat pointer type XUP, so the array type XUA
2103 is to be interpreted in the context of the fat pointer type XUB for
2104 debug info purposes. */
2107 {
2109 const bool convention_fortran_p
2118 Entity_Id gnat_index;
2122 /* Create the type for the component now, as it simplifies breaking
2123 type reference loops. */
2124 comp_type
2127 {
2128 /* As a side effect, the type may have been translated. */
2131 }
2133 /* We complete an existing dummy fat pointer type in place. This both
2134 avoids further complex adjustments in update_pointer_to and yields
2135 better debugging information in DWARF by leveraging the support for
2136 incomplete declarations of "tagged" types in the DWARF back-end. */
2139 {
2142 gnu_ptr_template =
2146 /* Save the contents of the dummy type for update_pointer_to. */
2152 }
2153 else
2154 {
2158 }
2160 /* Make a node for the array. If we are not defining the array
2161 suppress expanding incomplete types. */
2164 /* The component may refer to this type, so defer completion of any
2165 incomplete types. */
2167 {
2168 defer_incomplete_level++;
2170 }
2172 /* Build the fat pointer type. Use a "void *" object instead of
2173 a pointer to the array type since we don't have the array type
2174 yet (it will reference the fat pointer via the bounds). Note
2175 that we reuse the existing fields of a dummy type because for:
2177 type Arr is array (Positive range <>) of Element_Type;
2178 type Array_Ref is access Arr;
2179 Var : Array_Ref := Null;
2181 in a declarative part, Arr will be frozen only after Var, which
2182 means that the fields used in the CONSTRUCTOR built for Null are
2183 those of the dummy type, which in turn means that COMPONENT_REFs
2184 of Var may be built with these fields. Now if COMPONENT_REFs of
2185 Var are also built later with the fields of the final type, the
2186 aliasing machinery may consider that the accesses are distinct
2187 if the FIELD_DECLs are distinct as objects. */
2189 {
2198 }
2199 else
2200 {
2201 /* We make the fields addressable for the sake of compatibility
2202 with languages for which the regular fields are addressable. */
2203 tem
2213 }
2215 /* If the GNAT encodings are used, give the fat pointer type a name.
2216 If this is a packed type implemented specially, tell the debugger
2217 how to interpret the underlying bits by fetching the name of the
2218 implementation type. But, in any case, mark it as artificial so
2219 the debugger can skip it. */
2220 const Entity_Id gnat_name
2222 ? PAT
2224 tree xup_name
2229 gnat_entity);
2231 /* Build a reference to the template from a PLACEHOLDER_EXPR that
2232 is the fat pointer. This will be used to access the individual
2233 fields once we build them. */
2237 gnu_template_reference
2242 /* Now create the GCC type for each index and add the fields for that
2243 index to the template. */
2249 {
2251 const bool is_flb
2261 /* Update the maximum size of the array in elements. */
2263 gnu_max_size
2266 /* Now build the self-referential bounds of the index type. */
2270 /* Make the FIELD_DECLs for the low and high bounds of this
2271 type and then make extractions of these fields from the
2272 template. */
2275 gnu_index_type,
2278 /* Mark the field specifically for INSTANTIATE_LOAD_IN_EXPR. */
2285 gnu_index_type,
2288 /* Mark the field specifically for INSTANTIATE_LOAD_IN_EXPR. */
2295 /* We can't use build_component_ref here since the template type
2296 isn't complete yet. */
2298 {
2301 NULL_TREE);
2303 }
2307 NULL_TREE);
2313 /* Compute the size of this dimension. See the E_Array_Subtype
2314 case below for the rationale. */
2320 else
2321 gnu_high
2325 gnu_max,
2330 /* Make a range type with the new range in the Ada base type.
2331 Then make an index type with the size range in sizetype. */
2335 gnu_orig_min,
2336 gnu_orig_max),
2337 gnat_entity);
2341 }
2343 /* Install all the fields into the template. */
2348 gnu_template_fields
2351 debug_info_p);
2354 /* If Component_Size is not already specified, annotate it with the
2355 size of the component. */
2360 /* Compute the maximum size of the array in units. */
2362 gnu_max_size
2365 /* Now build the array type. */
2368 {
2376 }
2378 /* If this is a packed type implemented specially, then process the
2379 implementation type so it is elaborated in the proper scope. */
2383 /* Otherwise, if an alignment is specified, use it if valid and, if
2384 the alignment was requested with an explicit clause, state so. */
2386 {
2389 gnat_entity,
2393 }
2395 /* Tag top-level ARRAY_TYPE nodes for packed arrays and their
2396 implementation types as such so that the debug information back-end
2397 can output the appropriate description for them. */
2405 /* Adjust the type of the pointer-to-array field of the fat pointer
2406 and preserve its existing alias set, if any. Note that calling
2407 again record_component_aliases on the fat pointer is not enough
2408 because this may leave dangling references to the existing alias
2409 set from types containing a fat pointer component. If this is
2410 a packed type implemented specially, then use a ref-all pointer
2411 type since the implementation type may vary between constrained
2412 subtypes and unconstrained base type. */
2416 else
2421 /* If the maximum size doesn't overflow, use it. */
2428 /* See the above description for the rationale. */
2434 /* Create the type to be designated by thin pointers: a record type for
2435 the array and its template. We used to shift the fields to have the
2436 template at a negative offset, but this was somewhat of a kludge; we
2437 now shift thin pointer values explicitly but only those which have a
2438 TYPE_UNCONSTRAINED_ARRAY attached to the designated RECORD_TYPE.
2439 If the GNAT encodings are used, give it a name. */
2440 tree xut_name
2445 debug_info_p);
2450 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2451 corresponding fat pointer. */
2457 }
2465 /* This is the actual data type for array variables. Multidimensional
2466 arrays are implemented as arrays of arrays. Note that arrays which
2467 have sparse enumeration subtypes as index components create sparse
2468 arrays, which is obviously space inefficient but so much easier to
2469 code for now.
2471 Also note that the subtype never refers to the unconstrained array
2472 type, which is somewhat at variance with Ada semantics.
2474 First check to see if this is simply a renaming of the array type.
2475 If so, the result is the array type. */
2479 ;
2480 else
2481 {
2484 const bool convention_fortran_p
2494 /* First create the GCC type for each index and find out whether
2495 special types are needed for debugging information. */
2498 gnat_base_index
2504 {
2510 tree gnu_base_index_type
2516 /* We try to create subtypes for discriminants used as bounds
2517 that are more restrictive than those declared, by using the
2518 bounds of the index type of the base array type. This will
2519 make it possible to calculate the maximum size of the record
2520 type more conservatively. This may have already been done by
2521 the front-end (Exp_Ch3.Adjust_Discriminants), in which case
2522 there will be a conversion that needs to be removed first. */
2527 {
2531 gnu_base_orig_min,
2532 gnu_base_orig_max);
2533 }
2539 {
2543 gnu_base_orig_min,
2544 gnu_base_orig_max);
2545 }
2547 /* Update the maximum size of the array in elements. Here we
2548 see if any constraint on the index type of the base type
2549 can be used in the case of self-referential bounds on the
2550 index type of the array type. We look for a non-"infinite"
2551 and non-self-referential bound from any type involved and
2552 handle each bound separately. */
2554 {
2557 else
2566 else
2573 gnu_max_size
2575 }
2577 /* Convert the bounds to the base type for consistency below. */
2585 /* See if the base array type is already flat. If it is, we
2586 are probably compiling an ACATS test but it will cause the
2587 code below to malfunction if we don't handle it specially. */
2591 {
2595 }
2597 /* Similarly, if one of the values overflows in sizetype and the
2598 range is null, use 1..0 for the sizetype bounds. */
2603 {
2607 }
2609 /* If the minimum and maximum values both overflow in sizetype,
2610 but the difference in the original type does not overflow in
2611 sizetype, ignore the overflow indication. */
2615 && !TREE_OVERFLOW
2618 gnu_index_base_type,
2619 gnu_orig_max,
2620 gnu_orig_min))))
2621 {
2625 }
2627 /* Compute the size of this dimension in the general case. We
2628 need to provide GCC with an upper bound to use but have to
2629 deal with the "superflat" case. There are three ways to do
2630 this. If we can prove that the array can never be superflat,
2631 we can just use the high bound of the index type. */
2634 /* Bit-Packed Array Impl. Types are never superflat. */
2636 && Is_Bit_Packed_Array
2640 /* Otherwise, if the high bound is constant but the low bound is
2641 not, we use the expression (hb >= lb) ? lb : hb + 1 for the
2642 lower bound. Note that the comparison must be done in the
2643 original type to avoid any overflow during the conversion. */
2646 {
2648 gnu_min
2651 boolean_type_node,
2652 gnu_orig_max,
2653 gnu_orig_min),
2654 gnu_min,
2656 size_one_node));
2657 }
2659 /* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
2660 in all the other cases. Note that we use int_const_binop for
2661 the shift by 1 if the bound is constant to avoid any unwanted
2662 overflow. */
2663 else
2664 gnu_high
2667 boolean_type_node,
2668 gnu_orig_max,
2669 gnu_orig_min),
2670 gnu_max,
2673 size_one_node)
2675 size_one_node));
2677 /* Reuse the index type for the range type. Then make an index
2678 type with the size range in sizetype. */
2681 gnat_entity);
2683 /* Record whether the range is known to be null at compile time
2684 to disambiguate it from too large ranges. */
2690 /* We need special types for debugging information to point to
2691 the index types if they have variable bounds, are not integer
2692 types, are biased or are wider than sizetype. These are GNAT
2693 encodings, so we have to include them only when all encodings
2694 are requested. */
2704 }
2706 /* Then flatten: create the array of arrays. For an array type
2707 used to implement a packed array, get the component type from
2708 the original array type since the representation clauses that
2709 can affect it are on the latter. */
2712 {
2717 /* One of the above calls might have caused us to be elaborated,
2718 so don't blow up if so. */
2720 {
2723 }
2724 }
2725 else
2726 {
2728 debug_info_p);
2730 /* One of the above calls might have caused us to be elaborated,
2731 so don't blow up if so. */
2733 {
2736 }
2737 }
2739 /* Compute the maximum size of the array in units. */
2741 gnu_max_size
2744 /* Now build the array type. */
2746 {
2756 /* Clear the TREE_OVERFLOW flag, if any, for null arrays. */
2758 {
2761 }
2763 /* Kludge to clear the TREE_OVERFLOW flag for the sake of LTO
2764 on maximally-sized array types designed by access types. */
2774 {
2777 }
2778 }
2780 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
2784 /* If this is a multi-dimensional array and we are at global level,
2785 we need to make a variable corresponding to the stride of the
2786 inner dimensions. */
2788 {
2789 tree gnu_arr_type;
2794 {
2804 /* ??? For now, store the size as a multiple of the
2805 alignment of the element type in bytes so that we
2806 can see the alignment from the tree. */
2814 /* ??? create_type_decl is not invoked on the inner types so
2815 the MULT_EXPR node built above will never be marked. */
2817 }
2818 }
2820 /* Set the TYPE_PACKED flag on packed array types and also on their
2821 implementation types, so that the DWARF back-end can output the
2822 appropriate description for them. */
2831 /* If the maximum size doesn't overflow, use it. */
2838 /* If we need to write out a record type giving the names of the
2839 bounds for debugging purposes, do it now and make the record
2840 type a parallel type. This is not needed for a packed array
2841 since the bounds are conveyed by the original array type. */
2843 && debug_info_p
2845 {
2848 tree gnu_field;
2854 {
2858 /* Make sure to reference the types themselves, and not just
2859 their names, as the debugger may fall back on them. */
2865 }
2869 }
2871 /* If this is a packed array type, make the original array type a
2872 parallel/debug type. Otherwise, if GNAT encodings are used, do
2873 it for the base array type if it is not artificial to make sure
2874 that it is kept in the debug info. */
2876 {
2878 {
2879 tree gnu_name
2881 gnat_entity);
2884 }
2887 {
2888 tree gnu_base_decl
2895 }
2896 }
2898 /* Set our alias set to that of our base type. This gives all
2899 array subtypes the same alias set. */
2902 /* If this is a packed type implemented specially, then replace our
2903 type with the implementation type. */
2905 {
2906 /* First finish the type we had been making so that we output
2907 debugging information for it. */
2910 {
2911 const int quals
2912 = TYPE_QUAL_VOLATILE
2915 }
2916 /* Make it artificial only if the base type was artificial too.
2917 That's sort of "morally" true and will make it possible for
2918 the debugger to look it up by name in DWARF, which is needed
2919 in order to decode the packed array type. */
2920 tree gnu_tmp_decl
2924 gnat_entity);
2925 /* Save it as our equivalent in case the call below elaborates
2926 this type again. */
2932 /* Set the ___XP suffix for GNAT encodings. */
2942 /* We need to attach the index type to the type we just made so
2943 that the actual bounds can later be put into a template. */
2948 {
2950 {
2951 /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
2952 TYPE_MODULUS for modular types so we make an extra
2953 subtype if necessary. */
2955 gnu_inner
2962 /* Check for other cases of overloading. */
2964 }
2969 SET_TYPE_ACTUAL_BOUNDS
2976 SET_TYPE_ACTUAL_BOUNDS
2982 }
2983 }
2984 }
2988 /* Create the type for a string literal. */
2989 {
2990 Entity_Id gnat_full_type
2995 tree gnu_string_array_type
2997 tree gnu_string_index_type
3000 tree gnu_lower_bound
3003 tree gnu_length
3005 gnu_string_index_type);
3006 tree gnu_upper_bound
3008 gnu_lower_bound,
3011 integer_one_node)));
3012 tree gnu_index_type
3016 gnu_lower_bound,
3017 gnu_upper_bound),
3018 gnat_entity);
3020 gnu_type
3023 gnu_index_type);
3027 }
3030 /* Record Types and Subtypes
3032 A record type definition is transformed into the equivalent of a C
3033 struct definition. The fields that are the discriminants which are
3034 found in the Full_Type_Declaration node and the elements of the
3035 Component_List found in the Record_Type_Definition node. The
3036 Component_List can be a recursive structure since each Variant of
3037 the Variant_Part of the Component_List has a Component_List.
3039 Processing of a record type definition comprises starting the list of
3040 field declarations here from the discriminants and the calling the
3041 function components_to_record to add the rest of the fields from the
3042 component list and return the gnu type node. The function
3043 components_to_record will call itself recursively as it traverses
3044 the tree. */
3047 {
3051 {
3052 const Node_Id first_component
3054 tree gnu_component_type
3058 }
3060 Node_Id gnat_constr;
3063 tree gnu_get_parent;
3064 /* Set PACKED in keeping with gnat_to_gnu_field. */
3065 const int packed
3073 const bool is_extension
3076 const bool has_rep
3077 = is_extension
3083 /* See if all fields have a rep clause. Stop when we find one
3084 that doesn't. */
3093 {
3096 }
3098 /* If this is a record extension, go a level further to find the
3099 record definition. Also, verify we have a Parent_Subtype. */
3101 {
3108 }
3110 /* Make a node for the record type. */
3117 /* If the record type has discriminants, pointers to it may also point
3118 to constrained subtypes of it, so mark it as may_alias for LTO. */
3120 prepend_one_attribute
3123 gnat_entity);
3127 /* Some component may refer to this type, so defer completion of any
3128 incomplete types. */
3130 {
3131 defer_incomplete_level++;
3133 }
3135 /* If both a size and rep clause were specified, put the size on
3136 the record type now so that it can get the proper layout. */
3141 /* Always set the alignment on the record type here so that it can
3142 get the proper layout. */
3147 else
3148 {
3151 /* If a type needs strict alignment, then its type size will also
3152 be the RM size (see below). Cap the alignment if needed, lest
3153 it may cause this type size to become too large. */
3155 {
3160 }
3162 /* Similarly if an Object_Size clause has been specified. */
3164 {
3169 }
3170 }
3172 /* If we have a Parent_Subtype, make a field for the parent. If
3173 this record has rep clauses, force the position to zero. */
3175 {
3178 tree gnu_parent;
3181 /* A major complexity here is that the parent subtype will
3182 reference our discriminants in its Stored_Constraint list.
3183 But those must reference the parent component of this record
3184 which is precisely of the parent subtype we have not built yet!
3185 To break the circle we first build a dummy COMPONENT_REF which
3186 represents the "get to the parent" operation and initialize
3187 each of those discriminants to a COMPONENT_REF of the above
3188 dummy parent referencing the corresponding discriminant of the
3189 base type of the parent subtype. */
3194 gnu_dummy_parent_type),
3195 NULL_TREE);
3202 {
3203 tree gnu_field
3206 save_gnu_tree
3211 }
3213 /* Then we build the parent subtype. If it has discriminants but
3214 the type itself has unknown discriminants, this means that it
3215 doesn't contain information about how the discriminants are
3216 derived from those of the ancestor type, so it cannot be used
3217 directly. Instead it is built by cloning the parent subtype
3218 of the underlying record view of the type, for which the above
3219 derivation of discriminants has been made explicit. */
3222 {
3225 /* If we are defining the type, the underlying record
3226 view must already have been elaborated at this point.
3227 Otherwise do it now as its parent subtype cannot be
3228 technically elaborated on its own. */
3231 else
3236 /* Substitute the "get to the parent" of the type for that
3237 of its underlying record view in the cloned type. */
3242 {
3244 tree gnu_ref
3247 gnu_parent
3249 }
3250 }
3251 else
3254 /* The parent field needs strict alignment so, if it is to
3255 be created with a component clause below, then we need
3256 to apply the same adjustment as in gnat_to_gnu_field. */
3258 {
3259 /* ??? For historical reasons, we do it on strict-alignment
3260 platforms only, where it is really required. This means
3261 that a confirming representation clause will change the
3262 behavior of the compiler on the other platforms. */
3265 else
3266 parent_packed
3268 }
3270 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
3271 initially built. The discriminants must reference the fields
3272 of the parent subtype and not those of its base type for the
3273 placeholder machinery to properly work. */
3275 {
3276 /* The actual parent subtype is the full view. */
3278 {
3281 else
3283 }
3289 {
3290 Entity_Id field;
3299 }
3300 }
3302 /* The "get to the parent" COMPONENT_REF must be given its
3303 proper type... */
3306 /* ...and reference the _Parent field of this record. */
3307 gnu_field
3310 has_rep
3312 has_rep
3318 }
3320 /* Make the fields for the discriminants and put them into the record
3321 unless it's an Unchecked_Union. */
3326 {
3327 /* If this is a record extension and this discriminant is the
3328 renaming of another discriminant, we've handled it above. */
3333 gnu_field
3335 debug_info_p);
3337 /* Make an expression using a PLACEHOLDER_EXPR from the
3338 FIELD_DECL node just created and link that with the
3339 corresponding GNAT defining identifier. */
3347 {
3350 }
3351 }
3353 /* If we have a derived untagged type that renames discriminants in
3354 the parent type, the (stored) discriminants are just a copy of the
3355 discriminants of the parent type. This means that any constraints
3356 added by the renaming in the derivation are disregarded as far as
3357 the layout of the derived type is concerned. To rescue them, we
3358 change the type of the (stored) discriminants to a subtype with
3359 the bounds of the type of the visible discriminants. */
3361 && !is_extension
3367 /* Ignore access discriminants. */
3370 {
3373 tree gnu_ref
3377 /* GNU_REF must be an expression using a PLACEHOLDER_EXPR built
3378 just above for one of the stored discriminants. */
3386 }
3388 /* If this is a derived type with discriminants and these discriminants
3389 affect the initial shape it has inherited, factor them in. */
3391 && !is_extension
3399 {
3400 tree gnu_parent_type
3409 /* Set the layout of the type to match that of the parent type,
3410 doing required substitutions. Note that, if we do not use the
3411 GNAT encodings, we don't need debug info for the inner record
3412 types, as they will be part of the embedding variant record's
3413 debug info. */
3414 copy_and_substitute_in_layout
3416 gnu_subst_list,
3418 }
3419 else
3420 {
3421 /* Add the fields into the record type and finish it up. */
3428 NULL);
3430 /* Empty classes have the size of a storage unit in C++. */
3433 {
3437 }
3439 /* If the type needs strict alignment, then no object of the type
3440 may have a size smaller than the natural size, which means that
3441 the RM size of the type is equal to the type size. */
3445 /* If there are entities in the chain corresponding to components
3446 that we did not elaborate, ensure we elaborate their types if
3447 they are itypes. */
3456 }
3458 /* Fill in locations of fields. */
3460 }
3464 /* If an equivalent type is present, that is what we should use.
3465 Otherwise, fall through to handle this like a record subtype
3466 since it may have constraints. */
3468 {
3472 }
3474 /* ... fall through ... */
3481 /* Otherwise, first ensure the base type is elaborated. Then, if we are
3482 changing the type, make a new type with each field having the type of
3483 the field in the new subtype but the position computed by transforming
3484 every discriminant reference according to the constraints. We don't
3485 see any difference between private and non-private type here since
3486 derivations from types should have been deferred until the completion
3487 of the private type. */
3488 else
3489 {
3492 /* Some component may refer to this type, so defer completion of any
3493 incomplete types. We also need to do it for the special subtypes
3494 designated by access subtypes in case they are recursive, see the
3495 E_Access_Subtype case below. */
3500 {
3501 defer_incomplete_level++;
3503 }
3505 tree gnu_base_type
3509 {
3512 }
3514 /* When the subtype has discriminants and these discriminants affect
3515 the initial shape it has inherited, factor them in. But for an
3516 Unchecked_Union (it must be an itype), just return the type. */
3521 {
3524 tree gnu_unpad_base_type;
3533 /* Set the size, alignment and alias set of the type to match
3534 those of the base type, doing required substitutions. */
3536 gnu_subst_list);
3540 else
3543 /* Set the layout of the type to match that of the base type,
3544 doing required substitutions. We will output debug info
3545 manually below so pass false as last argument. */
3550 /* Fill in locations of fields. */
3553 /* If debugging information is being written for the type and if
3554 we are asked to output GNAT encodings, write a record that
3555 shows what we are a subtype of and also make a variable that
3556 indicates our size, if still variable. */
3559 {
3561 tree gnu_unpad_base_name
3569 build_reference_type
3571 gnu_subtype_marker,
3587 }
3589 /* Or else, if the subtype is artificial and GNAT encodings are
3590 not used, use the base record type as the debug type. */
3592 && artificial_p
3595 }
3597 /* Otherwise, go down all the components in the new type and make
3598 them equivalent to those in the base type. */
3599 else
3600 {
3610 gnat_to_gnu_field_decl
3613 }
3614 }
3619 /* Use the special descriptor type for dispatch tables if needed,
3620 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3621 Note that we are only required to do so for static tables in
3622 order to be compatible with the C++ ABI, but Ada 2005 allows
3623 to extend library level tagged types at the local level so
3624 we do it in the non-static case as well. */
3627 {
3631 }
3633 /* ... fall through ... */
3640 {
3641 /* The designated type and its equivalent type for gigi. */
3644 /* Whether it comes from a limited with. */
3645 const bool is_from_limited_with
3648 /* Whether it is a completed Taft Amendment type. Such a type is to
3649 be treated as coming from a limited with clause if it is not in
3650 the main unit, i.e. we break potential circularities here in case
3651 the body of an external unit is loaded for inter-unit inlining. */
3652 const bool is_completed_taft_type
3656 /* The "full view" of the designated type. If this is an incomplete
3657 entity from a limited with, treat its non-limited view as the full
3658 view. Otherwise, if this is an incomplete or private type, use the
3659 full view. In the former case, we might point to a private type,
3660 in which case, we need its full view. Also, we want to look at the
3661 actual type used for the representation, so this takes a total of
3662 three steps. */
3663 Entity_Id gnat_desig_full_direct_first
3664 = (is_from_limited_with
3668 Entity_Id gnat_desig_full_direct
3669 = ((is_from_limited_with
3674 Entity_Id gnat_desig_full
3676 /* The type actually used to represent the designated type, either
3677 gnat_desig_full or gnat_desig_equiv. */
3678 Entity_Id gnat_desig_rep;
3679 /* We want to know if we'll be seeing the freeze node for any
3680 incomplete type we may be pointing to. */
3681 const bool in_main_unit
3685 /* True if we make a dummy type here. */
3687 /* The mode to be used for the pointer type. */
3688 scalar_int_mode p_mode;
3689 /* The GCC type used for the designated type. */
3696 /* If either the designated type or its full view is an unconstrained
3697 array subtype, replace it with the type it's a subtype of. This
3698 avoids problems with multiple copies of unconstrained array types.
3699 Likewise, if the designated type is a subtype of an incomplete
3700 record type, use the parent type to avoid order of elaboration
3701 issues. This can lose some code efficiency, but there is no
3702 alternative. */
3713 /* Set the type that's the representation of the designated type. */
3714 gnat_desig_rep
3717 /* If we already know what the full type is, use it. */
3721 /* Get the type of the thing we are to point to and build a pointer to
3722 it. If it is a reference to an incomplete or private type with a
3723 full view that is a record, an array or an access, make a dummy type
3724 and get the actual type later when we have verified it is safe. */
3731 /* Likewise if this is a reference to a record, an array or a
3732 subprogram type and we are to defer elaborating incomplete
3733 types. We do this because this access type may be the full
3734 view of a private type. */
3741 /* If this is a reference from a limited_with type back to our
3742 main unit and there's a freeze node for it, either we have
3743 already processed the declaration and made the dummy type,
3744 in which case we just reuse the latter, or we have not yet,
3745 in which case we make the dummy type and it will be reused
3746 when the declaration is finally processed. In both cases,
3747 the pointer eventually created below will be automatically
3748 adjusted when the freeze node is processed. */
3749 || (in_main_unit
3750 && is_from_limited_with
3752 {
3755 }
3757 /* Otherwise handle the case of a pointer to itself. */
3759 {
3760 gnu_type
3764 }
3766 /* If expansion is disabled, the equivalent type of a concurrent type
3767 is absent, so we use the void pointer type. */
3771 /* If the ultimately designated type is an incomplete type with no full
3772 view, we use the void pointer type in LTO mode to avoid emitting a
3773 dummy type in the GIMPLE IR. We cannot do that in regular mode as
3774 the name of the dummy type in used by GDB for a global lookup. */
3780 /* Finally, handle the default case where we can just elaborate our
3781 designated type. */
3782 else
3785 /* It is possible that a call to gnat_to_gnu_type above resolved our
3786 type. If so, just return it. */
3788 {
3791 }
3793 /* Access-to-unconstrained-array types need a special treatment. */
3795 {
3796 /* If the processing above got something that has a pointer, then
3797 we are done. This could have happened either because the type
3798 was elaborated or because somebody else executed the code. */
3803 }
3805 /* If we haven't done it yet, build the pointer type the usual way. */
3807 {
3808 /* Modify the designated type if we are pointing only to constant
3809 objects, but don't do it for a dummy type. */
3812 gnu_desig_type
3815 gnu_type
3818 }
3820 /* If the designated type is not declared in the main unit and we made
3821 a dummy node for it, save our definition, elaborate the actual type
3822 and replace the dummy type we made with the actual one. But if we
3823 are to defer actually looking up the actual type, make an entry in
3824 the deferred list instead. If this is from a limited with, we may
3825 have to defer until the end of the current unit. */
3827 {
3829 gnu_type
3835 gnat_entity);
3842 && !is_from_limited_with
3844 {
3847 }
3848 else
3849 {
3859 }
3860 }
3861 }
3866 /* If we are just annotating types and have no equivalent record type,
3867 just use the void pointer type. */
3871 /* The run-time representation is the equivalent type. */
3872 else
3873 {
3876 }
3878 /* The designated subtype must be elaborated as well, if it does
3879 not have its own freeze node. */
3894 /* We treat this as identical to its base type; any constraint is
3895 meaningful only to the front-end. */
3899 /* The designated subtype must be elaborated as well, if it does
3900 not have its own freeze node. */
3905 {
3906 tree gnu_design_base_type
3911 /* If we are to defer elaborating incomplete types, make a dummy
3912 type node and elaborate it later. */
3914 {
3917 p->old_type
3922 }
3924 /* Otherwise elaborate the designated subtype only if its base type
3925 has already been elaborated. */
3929 }
3932 /* Subprogram Entities
3934 The following access functions are defined for subprograms:
3936 Etype Return type or Standard_Void_Type.
3937 First_Formal The first formal parameter.
3938 Is_Imported Indicates that the subprogram has appeared in
3939 an INTERFACE or IMPORT pragma. For now we
3940 assume that the external language is C.
3941 Is_Exported Likewise but for an EXPORT pragma.
3942 Is_Inlined True if the subprogram is to be inlined.
3944 Each parameter is first checked by calling must_pass_by_ref on its
3945 type to determine if it is passed by reference. For parameters which
3946 are copied in, if they are Ada In Out or Out parameters, their return
3947 value becomes part of a record which becomes the return type of the
3948 function (C function - note that this applies only to Ada procedures
3949 so there is no Ada return type). Additional code to store back the
3950 parameters will be generated on the caller side. This transformation
3951 is done here, not in the front-end.
3953 The intended result of the transformation can be seen from the
3954 equivalent source rewritings that follow:
3956 struct temp {int a,b};
3957 procedure P (A,B: In Out ...) is temp P (int A,B)
3958 begin {
3959 .. ..
3960 end P; return {A,B};
3961 }
3963 temp t;
3964 P(X,Y); t = P(X,Y);
3965 X = t.a , Y = t.b;
3967 For subprogram types we need to perform mainly the same conversions to
3968 GCC form that are needed for procedures and function declarations. The
3969 only difference is that at the end, we make a type declaration instead
3970 of a function declaration. */
3975 {
3976 tree gnu_ext_name
3978 const enum inline_status_t inline_status
3980 /* Subprograms marked both Intrinsic and Always_Inline need not
3981 have a body of their own. */
3982 const bool extern_flag
3984 || imported_p
3987 tree gnu_param_list;
3989 /* A parameter may refer to this type, so defer completion of any
3990 incomplete types. */
3992 {
3993 defer_incomplete_level++;
3995 }
3997 /* If the subprogram has an alias, it is probably inherited, so
3998 we can use the original one. If the original "subprogram"
3999 is actually an enumeration literal, it may be the first use
4000 of its type, so we must elaborate that type now. */
4002 {
4010 /* Elaborate any itypes in the parameters of this entity. */
4017 /* Materialize renamed subprograms in the debugging information
4018 when the renamed object is known at compile time; we consider
4019 such renamings as imported declarations.
4021 Because the parameters in generic instantiations are generally
4022 materialized as renamings, we often end up having both the
4023 renamed subprogram and the renaming in the same context and with
4024 the same name; in this case, renaming is both useless debug-wise
4025 and potentially harmful as name resolution in the debugger could
4026 return twice the same entity! So avoid this case. */
4028 && !artificial_p
4035 {
4040 }
4043 }
4045 /* Get the GCC tree for the (underlying) subprogram type. If the
4046 entity is an actual subprogram, also get the parameter list. */
4047 gnu_type
4051 {
4056 }
4058 /* Deal with platform-specific calling conventions. */
4060 prepend_one_attribute
4063 gnat_entity);
4065 /* If we should request stack realignment for a foreign convention
4066 subprogram, do so. Note that this applies to task entry points
4067 in particular. */
4069 prepend_one_attribute
4072 gnat_entity);
4074 /* Deal with a pragma Linker_Section on a subprogram. */
4080 /* If we are defining the subprogram and it has an Address clause
4081 we must get the address expression from the saved GCC tree for the
4082 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4083 the address expression here since the front-end has guaranteed
4084 in that case that the elaboration has no effects. If there is
4085 an Address clause and we are not defining the object, just
4086 make it a constant. */
4088 {
4092 gnu_address
4099 /* Convert the type of the object to a reference type that can
4100 alias everything as per RM 13.3(19). */
4101 gnu_type
4106 gnu_decl
4112 }
4114 /* If this is a mere subprogram type, just create the declaration. */
4116 {
4119 gnu_decl
4122 }
4124 /* Otherwise create the subprogram declaration with the external name,
4125 the type and the parameter list. However, if this a reference to
4126 the allocation routines, reuse the canonical declaration nodes as
4127 they come with special properties. */
4128 else
4129 {
4134 else
4135 gnu_decl
4141 gnat_entity);
4142 }
4143 }
4154 {
4155 const bool is_from_limited_with
4157 /* Get the "full view" of this entity. If this is an incomplete
4158 entity from a limited with, treat its non-limited view as the
4159 full view. Otherwise, use either the full view or the underlying
4160 full view, whichever is present. This is used in all the tests
4161 below. */
4162 const Entity_Id full_view
4163 = is_from_limited_with
4171 /* If this is an incomplete type with no full view, it must be a Taft
4172 Amendment type or an incomplete type coming from a limited context,
4173 in which cases we return a dummy type. Otherwise, we just get the
4174 type from its Etype. */
4176 {
4178 {
4181 }
4182 else
4183 {
4184 gnu_decl
4187 }
4188 }
4190 /* Or else, if we already made a type for the full view, reuse it. */
4194 /* Or else, if we are not defining the type or there is no freeze
4195 node on it, get the type for the full view. Likewise if this is
4196 a limited_with'ed type not declared in the main unit, which can
4197 happen for incomplete formal types instantiated on a type coming
4198 from a limited_with clause. */
4201 || (is_from_limited_with
4203 {
4206 }
4208 /* Otherwise, make a dummy type entry which will be replaced later.
4209 Save it as the full declaration's type so we can do any needed
4210 updates when we see it. */
4211 else
4212 {
4218 }
4219 }
4223 /* Class-wide types are always transformed into their root type. */
4232 /* If we are just annotating types and have no equivalent record type,
4233 just return void_type, except for root types that have discriminants
4234 because the discriminants will very likely be used in the declarative
4235 part of the associated body so they need to be translated. */
4237 {
4241 {
4243 Entity_Id gnat_field;
4245 /* This is a minimal version of the E_Record_Type handling. */
4252 {
4253 tree gnu_field
4265 }
4269 }
4270 else
4272 }
4274 /* Concurrent types are always transformed into their record type. */
4275 else
4286 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4287 we've already saved it, so we don't try to. */
4293 /* This is a SPARK annotation that only reaches here when compiling in
4294 ASIS mode. */
4302 }
4304 /* If this is the clone of a subtype, just reuse the cloned subtype; another
4305 approach would be to set the cloned subtype as the DECL_ORIGINAL_TYPE of
4306 the entity, which would generate a DW_TAG_typedef in the debug info, but
4307 at the cost of the duplication of the GCC type and, more annoyingly, of
4308 the need to update the copy if the cloned subtype is not complete yet. */
4310 {
4315 {
4322 }
4323 }
4325 /* If we had a case where we evaluated another type and it might have
4326 defined this one, handle it here. */
4328 {
4331 }
4333 /* If we are processing a type and there is either no DECL for it or
4334 we just made one, do some common processing for the type, such as
4335 handling alignment and possible padding. */
4337 {
4342 /* Process the attributes, if not already done. Note that the type is
4343 already defined so we cannot pass true for IN_PLACE here. */
4346 /* See if a size was specified, by means of either an Object_Size or
4347 a regular Size clause, and validate it if so.
4349 ??? Don't set the size for a String_Literal since it is either
4350 confirming or we don't handle it properly (if the low bound is
4351 non-constant). */
4353 {
4358 gnu_size
4362 /* ??? The test on Has_Size_Clause must be removed when "unknown" is
4363 no longer represented as Uint_0 (i.e. Use_New_Unknown_Rep). */
4366 gnu_size
4370 }
4372 /* If a size was specified, see if we can make a new type of that size
4373 by rearranging the type, for example from a fat to a thin pointer. */
4375 {
4376 gnu_type
4383 }
4385 /* If the alignment has not already been processed and this is not
4386 an unconstrained array type, see if an alignment is specified.
4387 If not, we pick a default alignment for atomic objects. */
4389 ;
4391 {
4395 /* Warn on suspiciously large alignments. This should catch
4396 errors about the (alignment,byte)/(size,bit) discrepancy. */
4398 {
4399 tree size;
4401 /* If a size was specified, take it into account. Otherwise
4402 use the RM size for records or unions as the type size has
4403 already been adjusted to the alignment. */
4409 else
4412 /* Consider an alignment as suspicious if the alignment/size
4413 ratio is greater or equal to the byte/bit ratio. */
4418 gnat_entity);
4419 }
4420 }
4431 /* See if we need to pad the type. If we did and built a new type,
4432 then create a stripped-down declaration for the original type,
4433 mainly for debugging, unless there was already one. */
4435 {
4443 gnat_entity);
4444 }
4446 /* Now set the RM size of the type. We cannot do it before padding
4447 because we need to accept arbitrary RM sizes on integral types. */
4451 /* Back-annotate the alignment of the type if not already set. */
4453 {
4457 /* If the default alignment of "double" or larger scalar types is
4458 specifically capped and this is not an array with an alignment
4459 clause on the component type, return the cap. */
4461 is_capped_double
4464 is_capped_double
4466 else
4471 else
4475 }
4477 /* Likewise for the size, if any. */
4479 {
4482 /* If the size is self-referential, annotate the maximum value
4483 after saturating it, if need be, to avoid a No_Uint value.
4484 But do not do it for cases where Analyze_Object_Declaration
4485 in Sem_Ch3 would build a default subtype for objects. */
4489 {
4490 const unsigned int align
4493 }
4495 /* If we are just annotating types and the type is tagged, the tag
4496 and the parent components are not generated by the front-end so
4497 alignment and sizes must be adjusted. */
4499 {
4501 const Entity_Id gnat_parent
4503 /* The following test for Known_Alignment preserves the old behavior,
4504 but is probably wrong. */
4505 const unsigned int inherited_align
4506 = derived_p
4511 const unsigned int align
4516 /* If there is neither size clause nor representation clause, the
4517 sizes need to be adjusted. */
4522 {
4523 tree offset
4524 = derived_p
4528 offset
4531 }
4536 /* Tagged types are Strict_Alignment so RM_Size = Esize. */
4539 }
4541 /* Otherwise no adjustment is needed. */
4542 else
4544 }
4546 /* Likewise for the RM size, if any. */
4551 /* If we are at global level, GCC applied variable_size to the size but
4552 this has done nothing. So, if it's not constant or self-referential,
4553 call elaborate_expression_1 to make a variable for it rather than
4554 calculating it each time. */
4559 {
4566 /* ??? For now, store the size as a multiple of the alignment in
4567 bytes so that we can see the alignment from the tree. */
4573 /* ??? gnu_type may come from an existing type so the MULT_EXPR node
4574 may not be marked by the call to create_type_decl below. */
4577 /* For a record type, deal with the variant part, if any, and handle
4578 the Ada size as well. */
4580 {
4585 {
4589 /* If the position of the variant part is constant, subtract
4590 it from the size of the type of the parent to get the new
4591 size. This manual CSE reduces the data size. */
4593 {
4601 }
4602 else
4603 {
4609 /* ??? For now, store the size as a multiple of the
4610 alignment in bytes so that we can see the alignment
4611 from the tree. */
4618 /* ??? For now, store the offset as a multiple of the
4619 alignment in bytes so that we can see the alignment
4620 from the tree. */
4624 DECL_OFFSET_ALIGN
4626 }
4630 }
4634 else
4635 ada_size
4639 }
4640 }
4642 /* Similarly, if this is a record type or subtype at global level, call
4643 elaborate_expression_2 on any field position. Skip any fields that
4644 we haven't made trees for to avoid problems with class-wide types. */
4649 {
4652 /* ??? For now, store the offset as a multiple of the alignment
4653 in bytes so that we can see the alignment from the tree. */
4656 {
4663 /* ??? The context of gnu_field is not necessarily gnu_type
4664 so the MULT_EXPR node built above may not be marked by
4665 the call to create_type_decl below. */
4667 }
4668 }
4670 /* Now check if the type allows atomic access. */
4674 /* If this is not an unconstrained array type, set some flags. */
4676 {
4679 /* Record the property that objects of tagged types are guaranteed to
4680 be properly aligned. This is necessary because conversions to the
4681 class-wide type are translated into conversions to the root type,
4682 which can be less aligned than some of its derived types. */
4687 /* Record whether the type is passed by reference. */
4691 /* Record whether an alignment clause was specified. At this point
4692 scalar types with a non-confirming clause have been wrapped into
4693 a record type, so only scalar types with a confirming clause are
4694 left untouched; we do not set the flag on them except if they are
4695 types whose default alignment is specifically capped in order not
4696 to lose the specified alignment. */
4707 /* Record whether a pragma Universal_Aliasing was specified. */
4711 /* If it is passed by reference, force BLKmode to ensure that
4712 objects of this type will always be put in memory. */
4715 }
4717 /* If this is a derived type, relate its alias set to that of its parent
4718 to avoid troubles when a call to an inherited primitive is inlined in
4719 a context where a derived object is accessed. The inlined code works
4720 on the parent view so the resulting code may access the same object
4721 using both the parent and the derived alias sets, which thus have to
4722 conflict. As the same issue arises with component references, the
4723 parent alias set also has to conflict with composite types enclosing
4724 derived components. For instance, if we have:
4726 type D is new T;
4727 type R is record
4728 Component : D;
4729 end record;
4731 we want T to conflict with both D and R, in addition to R being a
4732 superset of D by record/component construction.
4734 One way to achieve this is to perform an alias set copy from the
4735 parent to the derived type. This is not quite appropriate, though,
4736 as we don't want separate derived types to conflict with each other:
4738 type I1 is new Integer;
4739 type I2 is new Integer;
4741 We want I1 and I2 to both conflict with Integer but we do not want
4742 I1 to conflict with I2, and an alias set copy on derivation would
4743 have that effect.
4745 The option chosen is to make the alias set of the derived type a
4746 superset of that of its parent type. It trivially fulfills the
4747 simple requirement for the Integer derivation example above, and
4748 the component case as well by superset transitivity:
4750 superset superset
4751 R ----------> D ----------> T
4753 However, for composite types, conversions between derived types are
4754 translated into VIEW_CONVERT_EXPRs so a sequence like:
4756 type Comp1 is new Comp;
4757 type Comp2 is new Comp;
4758 procedure Proc (C : Comp1);
4760 C : Comp2;
4761 Proc (Comp1 (C));
4763 is translated into:
4765 C : Comp2;
4766 Proc ((Comp1 &) &VIEW_CONVERT_EXPR <Comp1> (C));
4768 and gimplified into:
4770 C : Comp2;
4771 Comp1 *C.0;
4772 C.0 = (Comp1 *) &C;
4773 Proc (C.0);
4775 i.e. generates code involving type punning. Therefore, Comp1 needs
4776 to conflict with Comp2 and an alias set copy is required.
4778 The language rules ensure the parent type is already frozen here. */
4782 {
4784 /* For constrained packed array subtypes, the implementation type is
4785 used instead of the nominal type. */
4793 }
4795 /* Finally get to the appropriate variant, except for the implementation
4796 type of a packed array because the GNU type might be further adjusted
4797 when the original array type is itself processed. */
4800 {
4801 const int quals
4802 = TYPE_QUAL_VOLATILE
4804 /* This is required by free_lang_data_in_type to disable the ODR. */
4809 }
4811 /* If we already made a decl, just set the type, otherwise create it. */
4813 {
4816 }
4817 else
4820 }
4822 /* If we haven't already, associate the ..._DECL node that we just made with
4823 the input GNAT entity node. */
4827 /* Now we are sure gnat_entity has a corresponding ..._DECL node,
4828 eliminate as many deferred computations as possible. */
4831 /* If this is an enumeration or floating-point type, we were not able to set
4832 the bounds since they refer to the type. These are always static. */
4835 {
4839 /* If this is a padded type, we need to use the underlying type. */
4843 /* If this is a floating point type and we haven't set a floating
4844 point type yet, use this in the evaluation of the bounds. */
4852 {
4853 /* Enumeration types have specific RM bounds. */
4856 }
4857 else
4858 {
4859 /* Floating-point types don't have specific RM bounds. */
4862 }
4863 }
4865 /* If we deferred processing of incomplete types, re-enable it. If there
4866 were no other disables and we have deferred types to process, do so. */
4870 {
4873 /* We are back to level 0 for the deferring of incomplete types.
4874 But processing these incomplete types below may itself require
4875 deferring, so preserve what we have and restart from scratch. */
4880 {
4887 }
4888 }
4890 /* If we are not defining this type, see if it's on one of the lists of
4891 incomplete types. If so, handle the list entry now. */
4893 {
4898 {
4902 }
4908 {
4914 }
4915 }
4918 force_global--;
4920 /* If this is a packed array type whose original array type is itself
4921 an itype without freeze node, make sure the latter is processed. */
4929 }
4931 /* Similar, but if the returned value is a COMPONENT_REF, return the
4932 FIELD_DECL. */
4934 tree
4936 {
4943 }
4945 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
4946 the GCC type corresponding to that entity. */
4948 tree
4950 {
4951 tree gnu_decl;
4953 /* The back end never attempts to annotate generic types. */
4961 }
4963 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
4964 the unpadded version of the GCC type corresponding to that entity. */
4966 tree
4968 {
4975 }
4977 /* Return whether the E_Subprogram_Type/E_Function/E_Procedure GNAT_ENTITY is
4978 a C++ imported method or equivalent.
4980 We use the predicate to find out whether we need to use METHOD_TYPE instead
4981 of FUNCTION_TYPE for GNAT_ENTITY for the sake compatibility with C++. This
4982 in turn determines whether the "thiscall" calling convention is used by the
4983 back-end for GNAT_ENTITY on 32-bit x86/Windows. */
4985 static bool
4987 {
4988 /* A constructor is a method on the C++ side. We deal with it now because
4989 it is declared without the 'this' parameter in the sources and, although
4990 the front-end will create a version with the 'this' parameter for code
4991 generation purposes, we want to return true for both versions. */
4995 /* Check that the subprogram has C++ convention. */
4999 /* And that the type of the first parameter (indirectly) has it too, but
5000 we make an exception for Interfaces because they need not be imported. */
5010 /* This is the main case: a C++ virtual method imported as a primitive
5011 operation of a tagged type. */
5015 /* This is set on the E_Subprogram_Type built for a dispatching call. */
5019 /* A thunk needs to be handled like its associated primitive operation. */
5023 /* Now on to the annoying case: a C++ non-virtual method, imported either
5024 as a non-primitive operation of a tagged type or as a primitive operation
5025 of an untagged type. We cannot reliably differentiate these cases from
5026 their static member or regular function equivalents in Ada, so we ask
5027 the C++ side through the mangled name of the function, as the implicit
5028 'this' parameter is not encoded in the mangled name of a method. */
5030 {
5038 DMGL_GNU_V3
5039 | DMGL_TYPES
5040 | DMGL_PARAMS
5046 /* We need to release MEM once we have a successful demangling. */
5053 {
5054 /* Make sure there is at least one parameter in C++ too. */
5056 {
5059 n_ada_args++;
5065 n_cpp_args++;
5071 }
5072 else
5074 }
5079 }
5082 }
5084 /* Return the inlining status of the GNAT subprogram SUBPROG. */
5086 static enum inline_status_t
5088 {
5096 {
5097 tree gnu_type;
5099 /* This is a kludge to work around a pass ordering issue: for small
5100 record types with many components, i.e. typically bit-fields, the
5101 initialization routine can contain many assignments that will be
5102 merged by the GIMPLE store merging pass. But this pass runs very
5103 late in the pipeline, in particular after the inlining decisions
5104 are made, so the inlining heuristics cannot take its outcome into
5105 account. Therefore, we optimistically override the heuristics for
5106 the initialization routine in this case. */
5108 && flag_store_merging
5116 /* If this is an expression function and we're not optimizing for size,
5117 override the heuristics, unless -gnatd.8 is specified. */
5119 && !optimize_size
5124 }
5127 }
5129 /* Finalize the processing of From_Limited_With incomplete types. */
5131 void
5133 {
5140 {
5144 {
5149 }
5152 }
5153 }
5155 /* Return the cloned subtype to be used for GNAT_ENTITY, if the latter is a
5156 kind of subtype that needs to be considered as a clone by Gigi, otherwise
5157 return Empty. */
5159 static Entity_Id
5161 {
5162 Node_Id gnat_decl;
5165 {
5170 /* ... fall through ... */
5173 /* If Cloned_Subtype is Present, this means that this record subtype has
5174 the same layout as that of the specified (sub)type, and also that the
5175 front-end guarantees that the component list is shared. */
5189 /* We return true for the subtypes generated for the actuals of formal
5190 private types in instantiations, so that these actuals are the types
5191 of the instantiated objects in the debug info. */
5199 /* Likewise for the full view of such subtypes when they are private. */
5201 {
5210 }
5215 }
5218 }
5220 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a kind
5221 of type (such E_Task_Type) that has a different type which Gigi uses
5222 for its representation. If the type does not have a special type for
5223 its representation, return GNAT_ENTITY. */
5225 Entity_Id
5227 {
5234 {
5269 }
5272 }
5274 /* Return a GCC tree for a type corresponding to the component type of the
5275 array type or subtype GNAT_ARRAY. DEFINITION is true if this component
5276 is for an array being defined. DEBUG_INFO_P is true if we need to write
5277 debug information for other types that we may create in the process. */
5279 static tree
5282 {
5286 tree gnu_comp_size;
5290 /* If an alignment is specified, use it as a cap on the component type
5291 so that it can be honored for the whole type, but ignore it for the
5292 original type of packed array types. */
5296 else
5299 /* Try to get a packable form of the component if needed. */
5301 && !is_bit_packed
5307 {
5310 }
5311 else
5314 /* Get and validate any specified Component_Size. */
5315 gnu_comp_size
5320 /* If the component type is a RECORD_TYPE that has a self-referential size,
5321 then use the maximum size for the component size. */
5327 /* If the array has aliased components and the component size is zero, force
5328 the unit size to ensure that the components have distinct addresses. */
5334 /* Honor the component size. This is not needed for bit-packed arrays. */
5336 {
5343 else
5346 /* We need to make sure that the size is a multiple of the alignment.
5347 But we do not misalign the component type because of the alignment
5348 of the array type here; this either must have been done earlier in
5349 the packed case or should be rejected in the non-packed case. */
5351 {
5356 }
5357 else
5363 /* If a padding record was made, declare it now since it will never be
5364 declared otherwise. This is necessary to ensure that its subtrees
5365 are properly marked. */
5368 gnat_array);
5369 }
5371 /* This is a very special case where the array has aliased components and the
5372 component size might be zero at run time. As explained above, we force at
5373 least the unit size but we don't want to build a distinct padding type for
5374 each invocation (they are not canonicalized if they have variable size) so
5375 we cache this special padding type as TYPE_PADDING_FOR_COMPONENT. */
5379 {
5382 else
5383 {
5384 gnu_comp_size
5391 gnat_array);
5392 }
5393 }
5395 /* Now check if the type of the component allows atomic access. */
5399 /* If the component type is a padded type made for a non-bit-packed array
5400 of scalars with reverse storage order, we need to propagate the reverse
5401 storage order to the padding type since it is the innermost enclosing
5402 aggregate type around the scalar. */
5404 && !is_bit_packed
5410 {
5411 const int quals
5412 = TYPE_QUAL_VOLATILE
5415 }
5418 }
5420 /* Return whether TYPE requires that formal parameters of TYPE be initialized
5421 when they are Out parameters passed by copy.
5423 This just implements the set of conditions listed in RM 6.4.1(12). */
5425 static bool
5427 {
5444 {
5452 }
5455 }
5457 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM, to be placed
5458 in the parameter list of GNAT_SUBPROG. GNU_PARAM_TYPE is the GCC tree for
5459 the type of the parameter. FIRST is true if this is the first parameter in
5460 the list of GNAT_SUBPROG. Also set CICO to true if the parameter must use
5461 the copy-in copy-out implementation mechanism.
5463 The returned tree is a PARM_DECL, except for the cases where no parameter
5464 needs to be actually passed to the subprogram; the type of this "shadow"
5465 parameter is then returned instead. */
5467 static tree
5470 {
5475 /* The parameter can be indirectly modified if its address is taken. */
5482 tree gnu_param;
5484 /* Make sure to use the proper SLOC for vector ABI warnings. */
5488 /* Builtins are expanded inline and there is no real call sequence involved.
5489 So the type expected by the underlying expander is always the type of the
5490 argument "as is". */
5495 /* Handle the first parameter of a valued procedure specially: it's a copy
5496 mechanism for which the parameter is never allocated. */
5498 {
5502 }
5504 /* Or else, see if a Mechanism was supplied that forced this parameter
5505 to be passed one way or another. */
5507 forced_by_ref
5509 && !foreign
5513 /* Positive mechanism means by copy for sufficiently small parameters. */
5515 {
5520 else
5522 }
5524 /* Otherwise, it's an unsupported mechanism so error out. */
5525 else
5526 {
5529 }
5531 /* Either for foreign conventions, or if the underlying type is not passed
5532 by reference and is as large and aligned as the original type, strip off
5533 a possible padding type. */
5535 {
5546 }
5548 /* For foreign conventions, pass arrays as pointers to the element type.
5549 First check for unconstrained array and get the underlying array. */
5551 gnu_param_type
5554 /* Arrays are passed as pointers to element type for foreign conventions. */
5556 {
5557 /* Strip off any multi-dimensional entries, then strip
5558 off the last array to get the component type. */
5566 }
5568 /* Fat pointers are passed as thin pointers for foreign conventions. */
5570 gnu_param_type
5573 /* Use a pointer type for the "this" pointer of C++ constructors. */
5575 {
5579 }
5581 /* If we were requested or muss pass by reference, do so.
5582 If we were requested to pass by copy, do so.
5583 Otherwise, for foreign conventions, pass In Out or Out parameters
5584 or aggregates by reference. For COBOL and Fortran, pass all
5585 integer and FP types that way too. For Convention Ada, use
5586 the standard Ada default. */
5590 && ((foreign
5592 || (foreign
5597 || (!foreign
5599 {
5600 /* We take advantage of 6.2(12) by considering that references built for
5601 parameters whose type isn't by-ref and for which the mechanism hasn't
5602 been forced to by-ref allow only a restricted form of aliasing. */
5603 restricted_aliasing_p
5607 }
5609 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
5618 /* If this is an Out parameter that isn't passed by reference and whose
5619 type doesn't require the initialization of formals, we don't make a
5620 PARM_DECL for it. Instead, it will be a VAR_DECL created when we
5621 process the procedure, so just return its type here. Likewise for
5622 the _Init parameter of an initialization procedure or the special
5623 parameter of a valued procedure, never pass them in. */
5625 && !by_ref
5626 && !by_component_ptr
5630 {
5633 }
5647 /* If no Mechanism was specified, indicate what we're using, then
5648 back-annotate it. */
5654 }
5656 /* Associate GNAT_SUBPROG with GNU_TYPE, which must be a dummy type, so that
5657 GNAT_SUBPROG is updated when GNU_TYPE is completed.
5659 Ada 2012 (AI05-019) says that freezing a subprogram does not always freeze
5660 the corresponding profile, which means that, by the time the freeze node
5661 of the subprogram is encountered, types involved in its profile may still
5662 be not yet frozen. That's why we need to update GNAT_SUBPROG when we see
5663 the freeze node of types involved in its profile, either types of formal
5664 parameters or the return type. */
5666 static void
5668 {
5676 {
5681 }
5683 /* Even if there is already a slot for GNU_TYPE, we need to set the flag
5684 because the vector might have been just emptied by update_profiles_with.
5685 This can happen when there are 2 freeze nodes associated with different
5686 views of the same type; the type will be really complete only after the
5687 second freeze node is encountered. */
5692 /* Make sure GNAT_SUBPROG is not associated twice with the same dummy type,
5693 since this would mean updating twice its profile. */
5695 {
5699 /* Entity_Id is a simple integer so we can implement a stable order on
5700 the vector with an ordered insertion scheme and binary search. */
5702 {
5709 else
5711 }
5713 /* l == u and therefore is the insertion point. */
5715 }
5716 else
5720 }
5722 /* Update the GCC tree previously built for the profile of GNAT_SUBPROG. */
5724 static void
5726 {
5727 tree gnu_param_list;
5732 {
5733 /* Builtins cannot have their address taken so we can reset them. */
5738 }
5744 /* If GNAT_SUBPROG is an actual subprogram, GNU_SUBPROG is a FUNCTION_DECL
5745 and needs to be adjusted too. */
5747 {
5749 tree gnu_ext_name
5754 }
5755 }
5757 /* Update the GCC trees previously built for the profiles involving GNU_TYPE,
5758 a dummy type which appears in profiles. */
5760 void
5762 {
5770 /* The flag needs to be reset before calling update_profile, in case
5771 associate_subprog_with_dummy_type is again invoked on GNU_TYPE. */
5780 }
5782 /* Return the GCC tree for GNAT_TYPE present in the profile of a subprogram.
5784 Ada 2012 (AI05-0151) says that incomplete types coming from a limited
5785 context may now appear as parameter and result types. As a consequence,
5786 we may need to defer their translation until after a freeze node is seen
5787 or to the end of the current unit. We also aim at handling temporarily
5788 incomplete types created by the usual delayed elaboration scheme. */
5790 static tree
5792 {
5793 /* This is the same logic as the E_Access_Type case of gnat_to_gnu_entity
5794 so the rationale is exposed in that place. These processings probably
5795 ought to be merged at some point. */
5797 const bool is_from_limited_with
5800 Entity_Id gnat_full_direct_first
5801 = (is_from_limited_with
5805 Entity_Id gnat_full_direct
5806 = ((is_from_limited_with
5814 tree gnu_type;
5820 && ((!in_main_unit
5827 {
5831 {
5838 }
5839 }
5844 else
5847 /* Access-to-unconstrained-array types need a special treatment. */
5849 {
5852 }
5855 }
5857 /* Return true if TYPE contains only integral data, recursively if need be. */
5859 static bool
5861 {
5863 {
5878 }
5881 }
5883 /* Return a GCC tree for a subprogram type corresponding to GNAT_SUBPROG.
5884 DEFINITION is true if this is for a subprogram being defined. DEBUG_INFO_P
5885 is true if we need to write debug information for other types that we may
5886 create in the process. Also set PARAM_LIST to the list of parameters.
5887 If GNAT_SUBPROG is bound to a GCC builtin, return the DECL for the builtin
5888 directly instead of its type. */
5890 static tree
5893 {
5900 tree gnu_return_type;
5903 /* Non-null for subprograms containing parameters passed by copy-in copy-out
5904 (In Out or Out parameters not passed by reference), in which case it is
5905 the list of nodes used to specify the values of the In Out/Out parameters
5906 that are returned as a record upon procedure return. The TREE_PURPOSE of
5907 an element of this list is a FIELD_DECL of the record and the TREE_VALUE
5908 is the PARM_DECL corresponding to that field. This list will be saved in
5909 the TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
5914 /* Although the semantics of "pure" units in Ada essentially match those of
5915 "const" in GNU C, the semantics of the Is_Pure flag in GNAT do not say
5916 anything about access to global memory, that's why it needs to be mapped
5917 to "pure" instead of "const" in GNU C. The property is orthogonal to the
5918 "nothrow" property only if the EH circuitry is explicit in the internal
5919 representation of the middle-end: if we are to completely hide the EH
5920 circuitry from it, we need to declare that calls to pure Ada subprograms
5921 that can throw have side effects, since they can trigger an "abnormal"
5922 transfer of control; therefore they cannot be "pure" in the GCC sense. */
5928 /* Look into the return type and get its associated GCC tree if it is not
5929 void, and then compute various flags for the subprogram type. But make
5930 sure not to do this processing multiple times. */
5937 {
5941 }
5943 else
5944 {
5945 /* For foreign convention/intrinsic subprograms, return System.Address
5946 as void * or equivalent; this comprises GCC builtins. */
5951 else
5954 /* If this function returns by reference or on the secondary stack, make
5955 the actual return type the reference type and make a note of that. */
5959 {
5962 }
5964 /* If the Mechanism is By_Reference, ensure this function uses the
5965 target's by-invisible-reference mechanism, which may not be the
5966 same as above (e.g. it might be passing an extra parameter). */
5970 /* Likewise, if the return type is itself By_Reference. */
5974 /* If the type is a padded type and the underlying type would not be
5975 passed by reference or the function has a foreign convention, return
5976 the underlying type. */
5978 && (!default_pass_by_ref
5983 /* If the return type is unconstrained, it must have a maximum size.
5984 Use the padded type as the effective return type. And ensure the
5985 function uses the target's by-invisible-reference mechanism to
5986 avoid copying too much data when it returns. */
5988 {
5992 /* If the size overflows to 0, set it to an arbitrary positive
5993 value so that assignments in the type are preserved. Their
5994 actual size is independent of this positive value. */
5998 {
6001 }
6007 /* Declare it now since it will never be declared otherwise. This
6008 is necessary to ensure that its subtrees are properly marked. */
6015 }
6017 /* If the return type has a size that overflows, we usually cannot have
6018 a function that returns that type. This usage doesn't really make
6019 sense anyway, so issue an error here. */
6024 {
6029 }
6031 /* If the return type is incomplete, there are 2 cases: if the function
6032 returns by reference, then the return type is only linked indirectly
6033 in the profile, so the profile can be seen as complete since it need
6034 not be further modified, only the reference types need be adjusted;
6035 otherwise the profile is incomplete and need be adjusted too. */
6037 {
6040 }
6044 || return_by_invisi_ref_p
6046 }
6048 /* A procedure (something that doesn't return anything) shouldn't be
6049 considered pure since there would be no reason for calling such a
6050 subprogram. Note that procedures with Out (or In Out) parameters
6051 have already been converted into a function with a return type.
6052 Similarly, if the function returns an unconstrained type, then the
6053 function will allocate the return value on the secondary stack and
6054 thus calls to it cannot be CSE'ed, lest the stack be reclaimed. */
6058 /* Loop over the parameters and get their associated GCC tree. While doing
6059 this, build a copy-in copy-out structure if we need one. */
6060 Entity_Id gnat_param;
6065 {
6066 const bool mech_is_by_ref
6073 /* For a variadic C function, do not build unnamed parameters. */
6078 /* Fetch an existing parameter with complete type and reuse it. But we
6079 didn't save the CICO property so we can only do it for In parameters
6080 or parameters passed by reference. */
6085 {
6088 }
6090 /* Otherwise translate the parameter type and act accordingly. */
6091 else
6092 {
6095 /* For foreign convention/intrinsic subprograms, pass System.Address
6096 as void * or equivalent; this comprises GCC builtins. */
6101 else
6104 /* If the parameter type is incomplete, there are 2 cases: if it is
6105 passed by reference, then the type is only linked indirectly in
6106 the profile, so the profile can be seen as complete since it need
6107 not be further modified, only the reference type need be adjusted;
6108 otherwise the profile is incomplete and need be adjusted too. */
6110 {
6111 Node_Id gnat_decl;
6115 && TYPE_IS_FAT_POINTER_P
6118 {
6120 gnu_param
6130 }
6132 /* ??? This is a kludge to support null procedures in spec taking
6133 a parameter with an untagged incomplete type coming from a
6134 limited context. The front-end creates a body without knowing
6135 anything about the non-limited view, which is illegal Ada and
6136 cannot be supported. Create a parameter with a fake type. */
6144 else
6145 {
6146 /* Build a minimal PARM_DECL without DECL_ARG_TYPE so that
6147 Call_to_gnu will stop if it encounters the PARM_DECL. */
6148 gnu_param
6150 gnu_param_type);
6152 gnu_param_type);
6154 }
6155 }
6157 /* Otherwise build the parameter declaration normally. */
6158 else
6159 {
6160 gnu_param
6164 /* We are returned either a PARM_DECL or a type if no parameter
6165 needs to be passed; in either case, adjust the type. */
6168 else
6169 {
6172 }
6173 }
6174 }
6176 /* If we have a GCC tree for the parameter, register it. */
6179 {
6180 gnu_param_type_list
6186 /* A pure function in the Ada sense which takes an access parameter
6187 may modify memory through it and thus cannot be considered pure
6188 in the GCC sense, unless it's access-to-function. Likewise it if
6189 takes a by-ref In Out or Out parameter. But if it takes a by-ref
6190 In parameter, then it may only read memory through it and can be
6191 considered pure in the GCC sense. */
6197 }
6199 /* If the parameter uses the copy-in copy-out mechanism, allocate a field
6200 for it in the return type and register the association. */
6202 {
6204 {
6207 /* If this is a function, we also need a field for the
6208 return value to be placed. */
6210 {
6211 tree gnu_field
6213 gnu_return_type,
6219 gnu_cico_list
6223 }
6226 /* Set a default alignment to speed up accesses. But we should
6227 not increase the size of the structure too much, lest it does
6228 not fit in return registers anymore. */
6231 }
6233 tree gnu_field
6244 }
6245 }
6247 /* If the subprogram uses the copy-in copy-out mechanism, possibly adjust
6248 and finish up the return type. */
6250 {
6251 /* If we have a CICO list but it has only one entry, we convert
6252 this function into a function that returns this object. */
6256 /* Do not finalize the return type if the subprogram is stubbed
6257 since structures are incomplete for the back-end. */
6259 {
6264 /* Try to promote the mode if the return type is fully returned
6265 in integer registers, again to speed up accesses. */
6267 && gnu_cico_only_integral_type
6269 NULL_TREE))
6270 {
6271 unsigned int size
6274 scalar_int_mode mode;
6279 {
6287 }
6288 }
6290 /* But demote the mode if the return type is partly returned in FP
6291 registers to avoid creating problematic paradoxical subregs.
6292 Note that we need to cater to historical 32-bit architectures
6293 that incorrectly use the mode to select the return mechanism. */
6295 && !gnu_cico_only_integral_type
6298 NULL_TREE))
6303 }
6306 }
6308 /* The lists have been built in reverse. */
6315 /* Turn imported C++ constructors into their callable form as done in the
6316 front-end, i.e. add the "this" pointer and void the return type. */
6320 {
6321 tree gnu_param_type
6324 tree gnu_param
6326 gnu_param_type);
6327 gnu_param_type_list
6332 }
6334 /* If the profile is incomplete, we only set the (temporary) return and
6335 parameter types; otherwise, we build the full type. In either case,
6336 we reuse an already existing GCC tree that we built previously here. */
6338 {
6340 ;
6341 else
6347 }
6348 else
6349 {
6351 {
6355 {
6359 }
6365 }
6366 else
6367 {
6369 {
6371 gnu_type
6374 }
6375 else
6376 gnu_type
6379 /* GNU_TYPE may be shared since GCC hashes types. Unshare it if it
6380 has a different TYPE_CI_CO_LIST or flags. */
6382 return_by_direct_ref_p,
6383 return_by_invisi_ref_p))
6384 {
6389 }
6390 }
6398 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
6399 corresponding DECL node and check the parameter association. */
6402 {
6406 /* If we have a builtin DECL for that function, use it. Check if
6407 the profiles are compatible and warn if they are not. Note that
6408 the checker is expected to post diagnostics in this case. */
6410 {
6412 {
6413 const enum built_in_function fncode
6417 {
6446 /* This is a generic builtin overloaded on its return
6447 type, so do type resolution based on it. */
6450 gnu_builtin_decl
6452 else
6453 {
6454 post_error
6456 gnat_subprog);
6457 post_error
6459 gnat_subprog);
6461 }
6465 /* This is a generic builtin overloaded on its third
6466 parameter type, so do type resolution based on it. */
6468 && type_for_atomic_builtin_p
6470 gnu_builtin_decl
6471 = resolve_atomic_builtin
6473 else
6474 {
6475 post_error
6477 gnat_subprog);
6478 post_error
6480 gnat_subprog);
6482 }
6488 post_error
6490 gnat_subprog);
6496 }
6497 }
6500 {
6501 const intrin_binding_t inb
6505 post_error
6507 gnat_subprog);
6510 }
6511 }
6513 /* Inability to find the builtin DECL most often indicates a genuine
6514 mistake, but imports of unregistered intrinsics are sometimes used
6515 on purpose to allow hooking in alternate bodies; we post a warning
6516 conditioned on Wshadow in this case, to let developers be notified
6517 on demand without risking false positives with common default sets
6518 of options. */
6521 }
6522 }
6527 }
6529 /* Return the external name for GNAT_SUBPROG given its entity name. */
6531 static tree
6533 {
6536 /* If there was no specified Interface_Name and the external and
6537 internal names of the subprogram are the same, only use the
6538 internal name to allow disambiguation of nested subprograms. */
6543 }
6545 /* Set TYPE_NONALIASED_COMPONENT on an array type built by means of
6546 build_nonshared_array_type. */
6548 static void
6550 {
6554 }
6556 /* Set TYPE_REVERSE_STORAGE_ORDER on an array type built by means of
6557 build_nonshared_array_type. */
6559 static void
6561 {
6565 }
6567 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
6569 static bool
6571 {
6578 return
6580 }
6582 /* Return true if the array type GNU_TYPE, which represents a dimension of
6583 GNAT_TYPE, has a non-aliased component in the back-end sense. */
6585 static bool
6587 {
6588 /* If the array type has an aliased component in the front-end sense,
6589 then it also has an aliased component in the back-end sense. */
6593 /* If this is a derived type, then it has a non-aliased component if
6594 and only if its parent type also has one. */
6596 {
6599 gnu_parent_type
6602 }
6604 /* For a multi-dimensional array type, find the component type. */
6609 /* Consider that an array of pointers has an aliased component, which is
6610 sort of logical and helps with Taft Amendment types in LTO mode. */
6614 /* Otherwise, rely exclusively on properties of the element type. */
6616 }
6618 /* Return true if GNAT_ADDRESS is a value known at compile-time. */
6620 static bool
6622 {
6623 /* Handle reference to a constant. */
6626 {
6630 }
6632 /* Catch System'To_Address. */
6637 }
6639 /* Return true if GNAT_INDIC, a N_Subtype_Indication node for the index of a
6640 FLB, cannot yield superflat objects, i.e. if the inequality HB >= LB - 1
6641 is true for these objects. LB and HB are the low and high bounds. */
6643 static bool
6645 {
6651 /* This is a FLB so LB is fixed. */
6655 {
6658 }
6659 else
6662 /* The low bound of the type is a lower bound for HB. */
6666 {
6669 }
6670 else
6673 /* We need at least a signed 64-bit type to catch most cases. */
6679 /* If the low bound is the smallest integer, nothing can be smaller. */
6685 }
6687 /* Return true if GNAT_RANGE, a N_Range node, cannot be superflat, i.e. if the
6688 inequality HB >= LB - 1 is true. LB and HB are the low and high bounds. */
6690 static bool
6692 {
6694 Node_Id gnat_scalar_range;
6697 /* This is the easy case. */
6701 /* If the low bound is not constant, take the worst case by finding an upper
6702 bound for its type, repeatedly if need be. */
6711 /* If the high bound is not constant, take the worst case by finding a lower
6712 bound for its type, repeatedly if need be. */
6721 /* If we have failed to find constant bounds, punt. */
6726 /* We need at least a signed 64-bit type to catch most cases. */
6732 /* If the low bound is the smallest integer, nothing can be smaller. */
6738 }
6740 /* Return true if GNU_EXPR is (essentially) the address of a CONSTRUCTOR. */
6742 static bool
6744 {
6751 }
6753 /* Return true if the size in units represented by GNU_SIZE can be handled by
6754 an allocation. If STATIC_P is true, consider only what can be done with a
6755 static allocation. */
6757 static bool
6759 {
6760 /* We can allocate a fixed size if it is a valid for the middle-end. */
6764 /* We can allocate a variable size if this isn't a static allocation. */
6765 else
6767 }
6769 /* Return true if GNU_EXPR needs a conversion to GNU_TYPE when used as the
6770 initial value of an object of GNU_TYPE. */
6772 static bool
6774 {
6775 /* Do not convert if the object's type is unconstrained because this would
6776 generate useless evaluations of the CONSTRUCTOR to compute the size. */
6781 /* Do not convert if the object's type is a padding record whose field is of
6782 self-referential size because we want to copy only the actual data. */
6786 /* Do not convert a call to a function that returns with variable size since
6787 we want to use the return slot optimization in this case. */
6792 /* Do not convert to a record type with a variant part from a record type
6793 without one, to keep the object simpler. */
6800 /* In all the other cases, convert the expression to the object's type. */
6802 }
6804 /* Add the contribution of [MIN, MAX] to the current number of elements N_ELEM
6805 of an array type and return the result, or NULL_TREE if it overflowed. */
6807 static tree
6809 {
6810 /* First deal with the empty case. */
6819 /* Compute the number of elements in this dimension. */
6820 tree this_n_elem
6826 /* Multiply the current number of elements by the result. */
6833 }
6835 /* Given GNAT_ENTITY, elaborate all expressions that are required to
6836 be elaborated at the point of its definition, but do nothing else. */
6838 void
6840 {
6842 {
6849 {
6853 /* ??? Tests to avoid Constraint_Error in static expressions
6854 are needed until after the front stops generating bogus
6855 conversions on bounds of real types. */
6863 }
6870 {
6871 Node_Id gnat_discriminant_expr;
6872 Entity_Id gnat_field;
6876 gnat_discriminant_expr
6881 /* Ignore access discriminants. */
6886 }
6889 }
6890 }
6892 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
6893 NAME, ARGS and ERROR_POINT. */
6895 static void
6898 tree attr_name,
6899 tree attr_args,
6900 Node_Id attr_error_point)
6901 {
6911 }
6913 /* Prepend to ATTR_LIST an entry for an attribute provided by GNAT_PRAGMA. */
6915 static void
6917 {
6923 /* Map the pragma at hand. Skip if this isn't one we know how to handle. */
6925 {
6956 }
6958 /* See what arguments we have and turn them into GCC trees for attribute
6959 handlers. The first one is always expected to be a string meant to be
6960 turned into an identifier. The next ones are all static expressions,
6961 among which strings meant to be turned into an identifier, except for
6962 a couple of specific attributes that require raw strings. */
6964 {
6969 const bool string_args
6979 {
6983 gnu_arg_list
6986 }
6987 }
6992 }
6994 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
6996 static void
6998 {
6999 Node_Id gnat_temp;
7001 /* Attributes are stored as Representation Item pragmas. */
7007 }
7009 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
7010 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
7011 return the GCC tree to use for that expression. S is the suffix to use
7012 if a variable needs to be created and DEFINITION is true if this is done
7013 for a definition of GNAT_ENTITY. If NEED_VALUE is true, we need a result;
7014 otherwise, we are just elaborating the expression for side-effects. If
7015 NEED_FOR_DEBUG is true, we need a variable for debugging purposes even
7016 if it isn't needed for code generation. */
7018 static tree
7021 {
7022 tree gnu_expr;
7024 /* If we already elaborated this expression (e.g. it was involved
7025 in the definition of a private type), use the old value. */
7029 /* If we don't need a value and this is static or a discriminant,
7030 we don't need to do anything. */
7037 /* If it's a static expression, we don't need a variable for debugging. */
7041 /* Otherwise, convert this tree to its GCC equivalent and elaborate it. */
7045 /* Save the expression in case we try to elaborate this entity again. Since
7046 it's not a DECL, don't check it. Don't save if it's a discriminant. */
7051 }
7053 /* Similar, but take a GNU expression and always return a result. */
7055 static tree
7058 {
7063 /* If GNU_EXPR contains a placeholder, just return it. We rely on the fact
7064 that an expression cannot contain both a discriminant and a variable. */
7068 /* If GNU_EXPR is neither a constant nor based on a read-only variable, make
7069 a variable that is initialized to contain the expression when the package
7070 containing the definition is elaborated. If this entity is defined at top
7071 level, replace the expression by the variable; otherwise use a SAVE_EXPR
7072 if this is necessary. */
7075 else
7076 {
7077 /* Skip any conversions and simple constant arithmetics to see if the
7078 expression is based on a read-only variable. */
7086 expr_variable_p
7087 = !(inner
7090 }
7092 /* We only need to use the variable if we are in a global context since GCC
7093 can do the right thing in the local case. However, when not optimizing,
7094 use it for bounds of loop iteration scheme to avoid code duplication. */
7095 use_variable = expr_variable_p
7096 && (expr_global_p
7097 || (!optimize
7098 && definition
7103 /* If the GNAT encodings are not used, we don't need a variable for debug
7104 info purposes if the expression is a constant or another variable, but
7105 we must be careful because we do not generate debug info for external
7106 variables so DECL_IGNORED_P is not stable across units. */
7110 || (!expr_public_p
7115 /* Now create it, possibly only for debugging purposes. */
7117 {
7118 /* The following variable creation can happen when processing the body
7119 of subprograms that are defined outside of the extended main unit and
7120 inlined. In this case, we are not at the global scope, and thus the
7121 new variable must not be tagged "external", as we used to do here as
7122 soon as DEFINITION was false. And note that we test Needs_Debug_Info
7123 here instead of NEED_FOR_DEBUG because, once the variable is created,
7124 whether or not debug information is generated for it is orthogonal to
7125 the reason why it was created in the first place. */
7126 tree gnu_decl
7134 /* Using this variable for debug (if need_for_debug is true) requires
7135 a proper location. The back-end will compute a location for this
7136 variable only if the variable is used by the generated code.
7137 Returning the variable ensures the caller will use it in generated
7138 code. Note that there is no need for a location if the debug info
7139 contains an integer constant. */
7142 }
7145 }
7147 /* Similar, but take an alignment factor and make it explicit in the tree. */
7149 static tree
7152 {
7154 return
7157 gnu_expr,
7158 unit_align),
7160 need_for_debug),
7161 unit_align);
7162 }
7164 /* Structure to hold internal data for elaborate_reference. */
7166 struct er_data
7167 {
7168 Entity_Id entity;
7171 };
7173 /* Wrapper function around elaborate_expression_1 for elaborate_reference. */
7175 static tree
7177 {
7181 /* This is what elaborate_expression_1 does if NEED_DEBUG is false. */
7185 /* If this is a COMPONENT_REF of a fat pointer, elaborate the entire fat
7186 pointer. This may be more efficient, but will also allow us to more
7187 easily find the match for the PLACEHOLDER_EXPR. */
7194 /* If this is the displacement of a pointer, elaborate the pointer and then
7195 displace the result. The actual purpose here is to drop the location on
7196 the expression, which may be problematic if replicated on references. */
7204 return
7206 }
7208 /* Elaborate the reference REF to be used as renamed object for GNAT_ENTITY.
7209 DEFINITION is true if this is done for a definition of GNAT_ENTITY and
7210 INIT is set to the first arm of a COMPOUND_EXPR present in REF, if any. */
7212 static tree
7215 {
7218 }
7220 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
7221 the value passed against the list of choices. */
7223 static tree
7225 {
7234 {
7236 tree gnu_test;
7239 {
7254 /* This represents either a subtype range or a static value of
7255 some kind; Ekind says which. */
7257 {
7263 }
7265 /* ... fall through ... */
7277 }
7279 /* Everything should be folded into constants at this point. */
7289 gnu_test
7300 gnu_test
7303 else
7308 else
7309 gnu_result
7312 }
7315 }
7317 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
7318 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
7320 static int
7322 {
7323 /* If the field is an array of variable size, we'd better not pack it because
7324 this would misalign it and, therefore, probably cause large temporarie to
7325 be created in case we need to take its address. See addressable_p and the
7326 notes on the addressability issues for further details. */
7331 /* In the other cases, we can honor the packing. */
7335 /* If the alignment of the record is specified and the field type
7336 is over-aligned, request Storage_Unit alignment for the field. */
7341 /* Likewise if the maximum alignment of the record is specified. */
7347 }
7349 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
7350 placed in GNU_RECORD_TYPE.
7352 PACKED is 1 if the enclosing record is packed or -1 if the enclosing
7353 record has Component_Alignment of Storage_Unit.
7355 DEFINITION is true if this field is for a record being defined.
7357 DEBUG_INFO_P is true if we need to write debug information for types
7358 that we may create in the process. */
7360 static tree
7363 {
7370 const bool is_full_access
7372 const bool is_independent
7374 const bool is_volatile
7378 /* We used to consider that volatile fields also require strict alignment,
7379 but that was an interpolation and would cause us to reject a pragma
7380 volatile on a packed record type containing boolean components, while
7381 there is no basis to do so in the RM. In such cases, the writes will
7382 involve load-modify-store sequences, but that's OK for volatile. The
7383 only constraint is the implementation advice whereby only the bits of
7384 the components should be accessed if they both start and end on byte
7385 boundaries, but that should be guaranteed by the GCC memory model.
7386 Note that we have some redundancies (is_full_access => is_independent,
7387 is_aliased => is_independent and is_by_ref => is_strict_alignment)
7388 so the following formula is sufficient. */
7394 /* Force the type of the Not_Handled_By_Others field to be that of the
7395 field in struct Exception_Data declared in raise.h instead of using
7396 the declared boolean type. We need to do that because there is no
7397 easy way to make use of a C compatible boolean type for the latter. */
7402 /* The qualifier to be used in messages. */
7406 {
7410 else
7412 }
7419 else
7422 /* The message to be used for incompatible size. */
7428 /* If a field requires strict alignment, we cannot pack it (RM 13.2(7)). */
7431 else
7434 /* If a size is specified, use it. Otherwise, if the record type is packed,
7435 use the official RM size. See "Handling of Type'Size Values" in Einfo
7436 for further details. */
7441 {
7445 }
7446 else
7449 /* Likewise for the position. */
7451 {
7454 }
7456 /* If the record has rep clauses and this is the tag field, make a rep
7457 clause for it as well. */
7460 {
7464 }
7466 else
7467 {
7470 }
7472 /* If the field's type is a fixed-size record that does not require strict
7473 alignment, and the record is packed or we have a position specified for
7474 the field that makes it a bitfield or we have a specified size that is
7475 smaller than that of the field's type, then see if we can get either an
7476 integral mode form of the field's type or a smaller form. If we can,
7477 consider that a size was specified for the field if there wasn't one
7478 already, so we know to make it a bitfield and avoid making things wider.
7480 Changing to an integral mode form is useful when the record is packed as
7481 we can then place the field at a non-byte-aligned position and so achieve
7482 tighter packing. This is in addition required if the field shares a byte
7483 with another field and the front-end lets the back-end handle the access
7484 to the field, because GCC cannot handle non-byte-aligned BLKmode fields.
7486 Changing to a smaller form is required if the specified size is smaller
7487 than that of the field's type and the type contains sub-fields that are
7488 padded, in order to avoid generating accesses to these sub-fields that
7489 are wider than the field.
7491 We avoid the transformation if it is not required or potentially useful,
7492 as it might entail an increase of the field's alignment and have ripple
7493 effects on the outer record type. A typical case is a field known to be
7494 byte-aligned and not to share a byte with another field. */
7500 || is_bitfield
7501 || (gnu_size
7503 {
7504 tree gnu_packable_type
7507 {
7511 }
7512 }
7514 /* Now check if the type of the field allows atomic access. */
7516 {
7517 const unsigned int align
7520 gnu_field_type
7524 }
7526 /* If a position is specified, check that it is valid. */
7528 {
7531 /* Ensure the position doesn't overlap with the parent subtype if there
7532 is one. It would be impossible to build CONSTRUCTORs and accessing
7533 the parent could clobber the component in the extension if directly
7534 done. We accept it with -gnatd.K for the sake of compatibility. */
7537 {
7542 post_error_ne_tree
7545 }
7547 /* If this field needs strict alignment, make sure that the record is
7548 sufficiently aligned and that the position and size are consistent
7549 with the type. But don't do it if we are just annotating types and
7550 the field's type is tagged, since tagged types aren't fully laid out
7551 in this mode. Also, note that atomic implies volatile so the inner
7552 test sequences ordering is significant here. */
7555 {
7562 /* If the position is not a multiple of the storage unit, then error
7563 out and reset the position. */
7565 bitsize_unit_node)))
7566 {
7572 }
7574 /* If the position is not a multiple of the alignment of the type,
7575 then error out and reset the position. */
7579 {
7582 field_s);
7589 }
7592 {
7596 /* If the size is not a multiple of the storage unit, then error
7597 out and reset the size. */
7599 bitsize_unit_node)))
7600 {
7606 }
7608 /* If the size is lower than that of the type, or greater for
7609 atomic and aliased, then error out and reset the size. */
7612 {
7616 type_size);
7618 }
7619 }
7620 }
7621 }
7623 else
7624 {
7625 /* If we are packing the record and the field is BLKmode, round the
7626 size up to a byte boundary. */
7629 }
7631 /* We need to make the size the maximum for the type if it is
7632 self-referential and an unconstrained type. In that case, we can't
7633 pack the field since we can't make a copy to align it. */
7635 && !gnu_size
7638 {
7641 }
7643 /* If a size is specified, adjust the field's type to it. */
7645 {
7646 tree orig_field_type;
7648 /* If the field's type is justified modular, we would need to remove
7649 the wrapper to (better) meet the layout requirements. However we
7650 can do so only if the field is not aliased to preserve the unique
7651 layout, if it has the same storage order as the enclosing record
7652 and if the prescribed size is not greater than that of the packed
7653 array to preserve the justification. */
7663 /* Similarly if the field's type is a misaligned integral type, but
7664 there is no restriction on the size as there is no justification. */
7671 gnu_field_type
7675 /* If the type has been extended, we may need to cap the alignment. */
7685 /* If a padding record was made, declare it now since it will never be
7686 declared otherwise. This is necessary to ensure that its subtrees
7687 are properly marked. */
7692 }
7694 /* Otherwise (or if there was an error), don't specify a position. */
7695 else
7698 /* If the field's type is a padded type made for a scalar field of a record
7699 type with reverse storage order, we need to propagate the reverse storage
7700 order to the padding type since it is the innermost enclosing aggregate
7701 type around the scalar. */
7710 /* Now create the decl for the field. */
7711 gnu_field
7718 /* If this is a discriminant, then we treat it specially: first, we set its
7719 index number for the back-annotation; second, we record whether it cannot
7720 be changed once it has been set for the computation of loop invariants;
7721 third, we make it addressable in order for the optimizer to more easily
7722 see that it cannot be modified by assignments to the other fields of the
7723 record (see create_field_decl for a more detailed explanation), which is
7724 crucial to hoist the offset and size computations of dynamic fields. */
7726 {
7732 }
7735 }
7737 /* Return true if at least one member of COMPONENT_LIST needs strict
7738 alignment. */
7740 static bool
7742 {
7743 Node_Id component_decl;
7748 {
7756 }
7759 }
7761 /* Return true if FIELD is an artificial field. */
7763 static bool
7765 {
7766 /* These fields are generated by the front-end proper. */
7770 /* These fields are generated by gigi. */
7775 }
7777 /* Return true if FIELD is a non-artificial field with self-referential
7778 size. */
7780 static bool
7782 {
7790 }
7792 /* Return true if FIELD is a non-artificial field with variable size. */
7794 static bool
7796 {
7804 }
7806 /* qsort comparer for the bit positions of two record components. */
7808 static int
7810 {
7813 const int ret
7817 }
7819 /* Sort the LIST of fields in reverse order of increasing position. */
7821 static tree
7823 {
7833 {
7836 }
7839 }
7841 /* Reverse function from gnat_to_gnu_field: return the GNAT field present in
7842 either GNAT_COMPONENT_LIST or the discriminants of GNAT_RECORD_TYPE, and
7843 corresponding to the GNU tree GNU_FIELD. */
7845 static Entity_Id
7847 Entity_Id gnat_record_type)
7848 {
7856 {
7860 }
7870 }
7872 /* Issue a warning for the problematic placement of GNU_FIELD present in
7873 either GNAT_COMPONENT_LIST or the discriminants of GNAT_RECORD_TYPE.
7874 IN_VARIANT is true if GNAT_COMPONENT_LIST is the list of a variant.
7875 DO_REORDER is true if fields of GNAT_RECORD_TYPE are being reordered. */
7877 static void
7881 {
7885 Entity_Id gnat_field
7890 = in_variant
7902 = do_reorder
7909 }
7911 /* Likewise but for every field present on GNU_FIELD_LIST. */
7913 static void
7917 {
7921 }
7923 /* Structure holding information for a given variant. */
7925 {
7926 /* The record type of the variant. */
7927 tree type;
7929 /* The name of the variant. */
7930 tree name;
7932 /* The qualifier of the variant. */
7933 tree qual;
7935 /* Whether the variant has a rep clause. */
7938 /* Whether the variant is packed. */
7943 /* Translate and chain GNAT_COMPONENT_LIST present in GNAT_RECORD_TYPE to
7944 GNU_FIELD_LIST, set the result as the field list of GNU_RECORD_TYPE and
7945 finish it up. Return true if GNU_RECORD_TYPE has a rep clause that affects
7946 the layout (see below). When called from gnat_to_gnu_entity during the
7947 processing of a record definition, the GCC node for the parent, if any,
7948 will be the single field of GNU_RECORD_TYPE and the GCC nodes for the
7949 discriminants will be on GNU_FIELD_LIST. The other call to this function
7950 is a recursive call for the component list of a variant and, in this case,
7951 GNU_FIELD_LIST is empty. Note that GNAT_COMPONENT_LIST may be Empty.
7953 PACKED is 1 if this is for a packed record or -1 if this is for a record
7954 with Component_Alignment of Storage_Unit.
7956 DEFINITION is true if we are defining this record type.
7958 CANCEL_ALIGNMENT is true if the alignment should be zeroed before laying
7959 out the record. This means the alignment only serves to force fields to
7960 be bitfields, but not to require the record to be that aligned. This is
7961 used for variants.
7963 ALL_REP is true if a rep clause is present for all the fields.
7965 UNCHECKED_UNION is true if we are building this type for a record with a
7966 Pragma Unchecked_Union.
7968 ARTIFICIAL is true if this is a type that was generated by the compiler.
7970 DEBUG_INFO is true if we need to write debug information about the type.
7972 IN_VARIANT is true if the componennt list is that of a variant.
7974 FIRST_FREE_POS, if nonzero, is the first (lowest) free field position in
7975 the outer record type down to this variant level. It is nonzero only if
7976 all the fields down to this level have a rep clause and ALL_REP is false.
7978 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
7979 with a rep clause is to be added; in this case, that is all that should
7980 be done with such fields and the return value will be false. */
7982 static bool
7989 {
7990 const bool needs_xv_encodings
8003 /* For each component referenced in a component declaration create a GCC
8004 field and add it to the list, skipping pragmas in the GNAT list. */
8012 {
8016 /* If present, the _Parent field must have been created as the single
8017 field of the record type. Put it before any other fields. */
8019 {
8022 }
8023 else
8024 {
8028 /* If this is the _Tag field, put it before any other fields. */
8032 /* If this is the _Controller field, put it before the other
8033 fields except for the _Tag or _Parent field. */
8035 {
8038 }
8040 /* If this is a regular field, put it after the other fields. */
8041 else
8042 {
8048 /* And record information for the final layout. */
8057 }
8058 }
8061 }
8063 /* At the end of the component list there may be a variant part. */
8066 else
8069 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
8070 mutually exclusive and should go in the same memory. To do this we need
8071 to treat each variant as a record whose elements are created from the
8072 component list for the variant. So here we create the records from the
8073 lists for the variants and put them all into the QUAL_UNION_TYPE.
8074 If this is an Unchecked_Union, we make a UNION_TYPE instead or
8075 use GNU_RECORD_TYPE if there are no fields so far. */
8077 {
8081 tree gnu_var_name
8084 tree gnu_union_name
8086 tree gnu_union_type;
8095 /* Reuse the enclosing union if this is an Unchecked_Union whose fields
8096 are all in the variant part, to match the layout of C unions. There
8097 is an associated check below. */
8100 else
8101 {
8102 gnu_union_type
8110 }
8112 /* If all the fields down to this level have a rep clause, find out
8113 whether all the fields at this level also have one. If so, then
8114 compute the new first free position to be passed downward. */
8117 {
8119 gnu_field;
8122 {
8125 this_first_free_pos
8127 }
8128 else
8129 {
8132 }
8133 }
8135 /* For an unchecked union with a fixed part, we need to compute whether
8136 we are at the innermost level of the variant part. */
8143 {
8146 }
8148 /* We build the variants in two passes. The bulk of the work is done in
8149 the first pass, that is to say translating the GNAT nodes, building
8150 the container types and computing the associated properties. However
8151 we cannot finish up the container types during this pass because we
8152 don't know where the variant part will be placed until the end. */
8156 {
8161 vinfo_t vinfo;
8169 /* Set the alignment of the inner type in case we need to make
8170 inner objects into bitfields, but then clear it out so the
8171 record actually gets only the alignment required. */
8177 /* Similarly, if the outer record has a size specified and all
8178 the fields have a rep clause, we can propagate the size. */
8180 {
8184 }
8186 /* Add the fields into the record type for the variant but note that
8187 we aren't sure to really use it at this point, see below. In the
8188 case of an unchecked union with a fixed part, we force the fields
8189 with a rep clause present in the innermost variant to be moved to
8190 the outer variant, so as to flatten the rep-ed layout as much as
8191 possible, the reason being that we cannot do any flattening when
8192 a subtype statically selects a variant later on, for example for
8193 an aggregate. */
8194 has_rep
8201 && !(unchecked_union
8202 && gnu_field_list
8206 /* Translate the qualifier and annotate the GNAT node. */
8210 /* Deal with packedness like in gnat_to_gnu_field. */
8212 {
8215 }
8216 else
8217 field_packed
8220 /* Push this variant onto the stack for the second pass. */
8228 /* Compute the global properties that will determine the placement of
8229 the variant part. */
8233 }
8235 /* Round up the first free position to the alignment of the variant part
8236 for the variants without rep clause. This will guarantee a consistent
8237 layout independently of the placement of the variant part. */
8241 /* In the second pass, the container types are adjusted if necessary and
8242 finished up, then the corresponding fields of the variant part are
8243 built with their qualifier, unless this is an unchecked union. */
8245 {
8249 /* If this is an Unchecked_Union whose fields are all in the variant
8250 part and we have a single field with no representation clause or
8251 placed at offset zero, use the field directly to match the layout
8252 of C unions. */
8254 && gnu_field_list
8258 {
8261 }
8262 else
8263 {
8264 /* Finalize the variant type now. We used to throw away empty
8265 record types but we no longer do that because we need them to
8266 generate complete debug info for the variant; otherwise, the
8267 union type definition will be lacking the fields associated
8268 with these empty variants. */
8270 {
8271 /* The variant part will be at offset 0 so we need to ensure
8272 that the fields are laid out starting from the first free
8273 position at this level. */
8275 tree gnu_rep_part;
8279 gnu_rep_part
8281 this_first_free_pos);
8286 }
8293 gnu_field
8295 gnu_union_type,
8296 all_rep_and_size
8305 }
8309 }
8311 /* Only make the QUAL_UNION_TYPE if there are non-empty variants. */
8313 {
8317 {
8321 }
8326 /* If GNU_UNION_TYPE is our record type, this means that we must have
8327 an Unchecked_Union whose fields are all in the variant part. Now
8328 verify that and, if so, just return. */
8330 {
8332 && !gnu_field_list
8335 }
8340 /* Deal with packedness like in gnat_to_gnu_field. */
8343 else
8344 union_field_packed
8347 gnu_variant_part
8349 all_rep_and_size
8355 }
8356 }
8358 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they do,
8359 pull them out and put them onto the appropriate list.
8361 Similarly, pull out the fields with zero size and no rep clause, as they
8362 would otherwise modify the layout and thus very likely run afoul of the
8363 Ada semantics, which are different from those of C here.
8365 Finally, if there is an aliased field placed in the list after fields
8366 with self-referential size, pull out the latter in the same way.
8368 Optionally, if the reordering mechanism is enabled, pull out the fields
8369 with self-referential size, variable size and fixed size not a multiple
8370 of a byte, so that they don't cause the regular fields to be either at
8371 self-referential/variable offset or misaligned. Note, in the latter
8372 case, that this can only happen in packed record types so the alignment
8373 is effectively capped to the byte for the whole record. But we don't
8374 do it for packed record types if not all fixed-size fiels can be packed
8375 and for non-packed record types if pragma Optimize_Alignment (Space) is
8376 specified, because this can prevent alignment gaps from being filled.
8378 Optionally, if the layout warning is enabled, keep track of the above 4
8379 different kinds of fields and issue a warning if some of them would be
8380 (or are being) reordered by the reordering mechanism.
8382 ??? If we reorder fields, the debugging information will be affected and
8383 the debugger print fields in a different order from the source code. */
8384 const bool do_reorder
8388 ? has_non_packed_fixed_size_field
8391 const bool w_reorder
8404 #define MOVE_FROM_FIELD_LIST_TO(LIST) \
8405 do { \
8406 if (gnu_last) \
8407 DECL_CHAIN (gnu_last) = gnu_next; \
8408 else \
8409 gnu_field_list = gnu_next; \
8410 \
8411 DECL_CHAIN (gnu_field) = (LIST); \
8412 (LIST) = gnu_field; \
8413 } while (0)
8417 {
8421 {
8424 }
8427 {
8438 }
8441 {
8444 }
8446 /* We don't need further processing in default mode. */
8448 {
8451 }
8454 {
8456 {
8460 do_reorder);
8461 else
8463 }
8466 {
8469 }
8470 }
8473 {
8475 {
8479 do_reorder);
8480 else
8482 }
8485 {
8488 }
8489 }
8491 else
8492 {
8493 /* If the field has no size, then it cannot be bit-packed. */
8494 const unsigned int bitp_size
8499 /* If the field is bit-packed, we move it to a temporary list that
8500 contains the contiguously preceding bit-packed fields, because
8501 we want to be able to put them back if the misalignment happens
8502 to cancel itself after several bit-packed fields. */
8504 {
8508 {
8511 }
8514 {
8517 }
8518 }
8520 /* No more bit-packed fields, move the existing ones to the end or
8521 put them back at their original location. */
8523 {
8527 {
8529 {
8532 gnat_component_list,
8534 do_reorder);
8535 else
8537 gnat_component_list,
8539 do_reorder);
8540 }
8547 }
8548 else
8549 {
8550 /* Rechain the temporary list in front of GNU_FIELD. */
8553 {
8558 else
8562 }
8563 }
8564 }
8566 else
8568 }
8571 }
8573 #undef MOVE_FROM_FIELD_LIST_TO
8577 /* If permitted, we reorder the fields as follows:
8579 1) all (groups of) fields whose length is fixed and multiple of a byte,
8580 2) the remaining fields whose length is fixed and not multiple of a byte,
8581 3) the remaining fields whose length doesn't depend on discriminants,
8582 4) all fields whose length depends on discriminants,
8583 5) the variant part,
8585 within the record and within each variant recursively. */
8588 {
8589 /* If we have pending bit-packed fields, warn if they would be moved
8590 to after regular fields. */
8594 {
8599 else
8603 }
8604 }
8607 {
8608 /* If we have pending bit-packed fields on the temporary list, we put
8609 them either on the bit-packed list or back on the regular list. */
8611 {
8614 else
8616 }
8618 gnu_field_list
8622 }
8624 /* Otherwise, if there is an aliased field placed after a field whose length
8625 depends on discriminants, we put all the fields of the latter sort, last.
8626 We need to do this in case an object of this record type is mutable. */
8630 /* If P_REP_LIST is nonzero, this means that we are asked to move the fields
8631 in our REP list to the previous level because this level needs them in
8632 order to do a correct layout, i.e. avoid having overlapping fields. */
8636 /* Deal with the case of an extension of a record type with variable size and
8637 partial rep clause, for which the _Parent field is forced at offset 0 and
8638 has variable size. Note that we cannot do it if the field has fixed size
8639 because we rely on the presence of the REP part built below to trigger the
8640 reordering of the fields in a derived record type when all the fields have
8641 a fixed position. */
8645 && !variants_have_rep
8646 && first_free_pos
8649 {
8653 }
8655 /* Otherwise, sort the fields by bit position and put them into their own
8656 record, before the others, if we also have fields without rep clause. */
8658 {
8661 /* If all the fields have a rep clause, we can do a flat layout. */
8662 layout_with_rep = !gnu_field_list
8665 /* Same as above but the extension itself has a rep clause, in which case
8666 we need to set aside the _Parent field to lay out the REP part. */
8668 && !layout_with_rep
8669 && !variants_have_rep
8670 && first_free_pos
8673 {
8676 }
8677 else
8680 gnu_rep_type
8683 /* Sort the fields in order of increasing bit position. */
8689 {
8692 }
8698 {
8702 }
8704 /* Do the layout of the REP part, if any. */
8707 else
8708 {
8715 /* If FIRST_FREE_POS is nonzero, we need to ensure that the fields
8716 without rep clause are laid out starting from this position.
8717 Therefore, we force it as a minimal size on the REP part. */
8718 tree gnu_rep_part
8721 /* If this is an extension, put back the _Parent field as the first
8722 field of the REP part at offset 0 and update its layout. */
8724 {
8730 {
8737 }
8738 }
8743 /* Chain the REP part at the beginning of the field list. */
8746 }
8747 }
8749 /* Chain the variant part at the end of the field list. */
8761 /* Chain the fields with zero size at the beginning of the field list. */
8767 }
8769 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
8770 placed into an Esize, Component_Bit_Offset, or Component_Size value
8771 in the GNAT tree. */
8773 static Uint
8775 {
8777 TCode tcode;
8781 /* See if we've already saved the value for this node. */
8783 {
8791 }
8792 else
8795 /* If we do not return inside this switch, TCODE will be set to the
8796 code to be used in a call to Create_Node. */
8798 {
8800 /* For negative values, build NEGATE_EXPR of the opposite. Such values
8801 can appear for discriminants in expressions for variants. */
8803 {
8807 }
8808 else
8813 /* The only case we handle here is a simple discriminant reference. */
8815 {
8819 /* Climb up the chain of successive extensions, if any. */
8826 {
8827 /* Fall through to common processing as a FIELD_DECL. */
8830 }
8831 else
8833 }
8834 else
8843 CASE_CONVERT:
8847 /* Now just list the operations we handle. */
8875 /* Turn addition of negative constant into subtraction. */
8878 {
8883 }
8885 /* ... fall through ... */
8889 /* Fold conversions from bytes to bits into inner operations. */
8892 {
8896 {
8900 widest_int op1;
8904 else
8905 {
8910 }
8912 }
8913 }
8918 /* For negative values in sizetype, build NEGATE_EXPR of the opposite.
8919 Such values can appear in expressions with aligning patterns. */
8921 {
8925 }
8929 /* In regular mode, inline back only if symbolic annotation is requested
8930 in order to avoid memory explosion on big discriminated record types.
8931 But not in ASIS mode, as symbolic annotation is required for DDA. */
8933 {
8936 }
8937 else
8942 }
8944 /* Now get each of the operands that's relevant for this code. If any
8945 cannot be expressed as a repinfo node, say we can't. */
8948 {
8952 }
8956 /* Save the result in the cache. */
8958 {
8960 /* We can't assume the hash table data hasn't moved since the initial
8961 look up, so we have to search again. Allocating and inserting an
8962 entry at that point would be an alternative, but then we'd better
8963 discard the entry if we decided not to cache it. */
8969 }
8972 }
8974 /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
8975 and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
8976 size and alignment used by Gigi. Prefer SIZE over TYPE_SIZE if non-null.
8977 BY_REF is true if the object is used by reference. */
8979 void
8981 {
8983 {
8986 else
8988 }
8991 {
9000 }
9005 }
9007 /* Return first element of field list whose TREE_PURPOSE is the same as ELEM.
9008 Return NULL_TREE if there is no such element in the list. */
9010 static tree
9012 {
9014 {
9019 }
9021 }
9023 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding GCC type,
9024 set Component_Bit_Offset and Esize of the components to the position and
9025 size used by Gigi. */
9027 static void
9029 {
9030 /* For an extension, the inherited components have not been translated because
9031 they are fetched from the _Parent component on the fly. */
9032 const bool is_extension
9035 /* We operate by first making a list of all fields and their position (we
9036 can get the size easily) and then update all the sizes in the tree. */
9037 tree gnu_list
9048 {
9050 gnu_list);
9052 {
9056 /* If we are just annotating types and the type is tagged, the tag
9057 and the parent components are not generated by the front-end so
9058 we need to add the appropriate offset to each component without
9059 representation clause. */
9063 {
9064 tree parent_bit_offset;
9066 /* For a component appearing in the current extension, the
9067 offset is the size of the parent. */
9070 parent_bit_offset
9072 bitsizetype);
9073 else
9077 parent_bit_offset
9081 offset
9085 parent_bit_offset,
9086 bitsize_unit_node)));
9087 }
9089 /* If the field has a variable offset, also compute the normalized
9090 position since it's easier to do on trees here than to deduce
9091 it from the annotated expression of Component_Bit_Offset. */
9093 {
9099 }
9101 Set_Component_Bit_Offset
9105 Set_Esize
9108 }
9110 {
9111 /* If there is no entry, this is an inherited component whose
9112 position is the same as in the parent type. */
9115 /* If we are just annotating types, discriminants renaming those of
9116 the parent have no entry so deal with them specifically. */
9123 {
9128 }
9134 }
9135 }
9136 }
9138 /* Scan all fields in GNU_TYPE and return a TREE_LIST where TREE_PURPOSE is
9139 the FIELD_DECL and TREE_VALUE a TREE_VEC containing the byte position, the
9140 value to be placed into DECL_OFFSET_ALIGN and the bit position. The list
9141 of fields is flattened, except for variant parts if DO_NOT_FLATTEN_VARIANT
9142 is set to true. GNU_POS is to be added to the position, GNU_BITPOS to the
9143 bit position, OFFSET_ALIGN is the present offset alignment. GNU_LIST is a
9144 pre-existing list to be chained to the newly created entries. */
9146 static tree
9149 {
9150 tree gnu_field;
9153 gnu_field;
9155 {
9160 unsigned int our_offset_align
9169 /* Recurse on internal fields, flattening the nested fields except for
9170 those in the variant part, if requested. */
9172 {
9176 gnu_list
9180 else
9181 gnu_list
9185 }
9186 }
9189 }
9191 /* Return a list describing the substitutions needed to reflect the
9192 discriminant substitutions from GNAT_TYPE to GNAT_SUBTYPE. They can
9193 be in any order. The values in an element of the list are in the form
9194 of operands to SUBSTITUTE_IN_EXPR. DEFINITION is true if this is for
9195 a definition of GNAT_SUBTYPE. */
9199 {
9201 Entity_Id gnat_discrim;
9202 Node_Id gnat_constr;
9209 /* Ignore access discriminants. */
9211 {
9213 tree replacement
9217 /* If this is a definition, we need to make sure that the SAVE_EXPRs
9218 are instantiated on every possibly path in size computations. */
9224 }
9227 }
9229 /* Scan all fields in {GNU_QUAL_UNION_TYPE,GNAT_VARIANT_PART} and return a list
9230 describing the variants of GNU_QUAL_UNION_TYPE that are still relevant after
9231 applying the substitutions described in SUBST_LIST. GNU_LIST is an existing
9232 list to be prepended to the newly created entries. */
9237 {
9238 Node_Id gnat_variant;
9239 tree gnu_field;
9242 gnat_variant
9246 gnu_field;
9248 gnat_variant
9252 {
9260 /* If the new qualifier is not unconditionally false, its variant may
9261 still be accessed. */
9263 {
9265 variant_desc v
9270 /* Annotate the GNAT node if present. */
9274 /* Recurse on the variant subpart of the variant, if any. */
9277 gnu_list
9280 ? Variant_Part
9283 subst_list,
9284 gnu_list);
9286 /* If the new qualifier is unconditionally true, the subsequent
9287 variants cannot be accessed. */
9290 }
9291 }
9294 }
9296 /* If SIZE has overflowed, return the maximum valid size, which is the upper
9297 bound of the signed sizetype in bits, rounded down to ALIGN. Otherwise
9298 return SIZE unmodified. */
9300 static tree
9302 {
9304 {
9305 size
9310 }
9313 }
9315 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
9316 corresponding to GNAT_OBJECT. If the size is valid, return an INTEGER_CST
9317 corresponding to its value. Otherwise, return NULL_TREE. KIND is set to
9318 VAR_DECL if we are specifying the size of an object, TYPE_DECL for the
9319 size of a type, and FIELD_DECL for the size of a field. COMPONENT_P is
9320 true if we are being called to process the Component_Size of GNAT_OBJECT;
9321 this is used only for error messages. ZERO_OK is true if a size of zero
9322 is permitted; if ZERO_OK is false, it means that a size of zero should be
9323 treated as an unspecified size. S1 and S2 are used for error messages. */
9325 static tree
9329 {
9330 Node_Id gnat_error_node;
9333 /* Return 0 if no size was specified. */
9337 /* Ignore a negative size since that corresponds to our back-annotation. */
9341 /* Find the node to use for error messages. */
9350 else
9353 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
9354 but cannot be represented in bitsizetype. */
9357 {
9360 gnat_object);
9361 else
9363 gnat_object);
9365 }
9367 /* Ignore a zero size if it is not permitted. */
9371 /* The size of objects is always a multiple of a byte. */
9374 {
9378 else
9382 }
9384 /* If this is an integral type or a bit-packed array type, the front-end has
9385 already verified the size, so we need not do it again (which would mean
9386 checking against the bounds). However, if this is an aliased object, it
9387 may not be smaller than the type of the object. */
9392 /* If the object is a record that contains a template, add the size of the
9393 template to the specified size. */
9400 /* If the old size is self-referential, get the maximum size. */
9404 /* If this is an access type or a fat pointer, the minimum size is that given
9405 by the smallest integral mode that's valid for pointers. */
9407 {
9412 }
9414 /* Issue an error either if the default size of the object isn't a constant
9415 or if the new size is smaller than it. */
9418 {
9423 {
9426 }
9429 else
9435 }
9438 }
9440 /* Similarly, but both validate and process a value of RM size. This routine
9441 is only called for types. */
9443 static void
9445 {
9446 Node_Id gnat_attr_node;
9449 /* Do nothing if no size was specified. */
9453 /* Only issue an error if a Value_Size clause was explicitly given for the
9454 entity; otherwise, we'd be duplicating an error on the Size clause. */
9455 gnat_attr_node
9460 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
9461 but cannot be represented in bitsizetype. */
9464 {
9467 gnat_entity);
9469 }
9471 /* Ignore a zero size unless a Value_Size clause exists, or a size clause
9472 exists, or this is an integer type, in which case the front-end will
9473 have always set it. */
9482 /* If the old size is self-referential, get the maximum size. */
9486 /* Issue an error either if the old size of the object isn't a constant or
9487 if the new size is smaller than it. The front-end has already verified
9488 this for scalar and bit-packed array types. */
9496 {
9498 post_error_ne_tree
9502 }
9504 /* Otherwise, set the RM size proper for integral types... */
9511 /* ...or the Ada size for record and union types. */
9515 }
9517 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
9518 a type or object whose present alignment is ALIGN. If this alignment is
9519 valid, return it. Otherwise, give an error and return ALIGN. */
9521 static unsigned int
9523 {
9526 Node_Id gnat_error_node;
9528 /* Don't worry about checking alignment if alignment was not specified
9529 by the source program and we already posted an error for this entity. */
9533 /* Post the error on the alignment clause if any. Note, for the implicit
9534 base type of an array type, the alignment clause is on the first
9535 subtype. */
9543 gnat_error_node =
9546 else
9549 /* Within GCC, an alignment is an integer, so we must make sure a value is
9550 specified that fits in that range. Also, there is an upper bound to
9551 alignments we can support/allow. */
9559 {
9563 /* If the default alignment of "double" or larger scalar types is
9564 specifically capped and the new alignment is above the cap, do
9565 not post an error and change the alignment only if there is an
9566 alignment clause; this makes it possible to have the associated
9567 GCC type overaligned by default for performance reasons. */
9569 {
9570 Entity_Id gnat_type
9572 is_capped_double
9574 }
9576 {
9577 Entity_Id gnat_type
9579 is_capped_double
9581 }
9582 else
9586 {
9589 }
9590 else
9591 {
9598 }
9599 }
9600 else
9601 {
9605 }
9608 }
9610 /* Promote the alignment of GNU_TYPE for an object with GNU_SIZE corresponding
9611 to GNAT_ENTITY. Return a positive value on success or zero on failure. */
9613 static unsigned int
9615 {
9618 /* No point in promoting the alignment if this doesn't prevent BLKmode access
9619 to the object, in particular block copy, as this will for example disable
9620 the NRV optimization for it. No point in jumping through all the hoops
9621 needed in order to support BIGGEST_ALIGNMENT if we don't really have to.
9622 So we cap to the smallest alignment that corresponds to a known efficient
9623 memory access pattern, except for a full access entity. */
9625 {
9628 }
9629 else
9630 {
9633 }
9638 /* Do the promotion within the above limits. */
9644 else
9647 /* But make sure not to under-align the object. */
9651 /* And honor the minimum valid atomic alignment, if any. */
9652 #ifdef MINIMUM_ATOMIC_ALIGNMENT
9655 #endif
9658 }
9660 /* Return whether GNAT_ENTITY is a simple constant, i.e. it represents only
9661 its value and reading it has no side effects. */
9663 bool
9665 {
9671 }
9673 /* Verify that TYPE is something we can implement atomically. If not, issue
9674 an error for GNAT_ENTITY. COMPONENT_P is true if we are being called to
9675 process a component type. */
9677 static void
9679 {
9681 Node_Id gnat_node;
9682 machine_mode mode;
9685 tree size;
9687 /* If this is an anonymous base type, nothing to check, the error will be
9688 reported on the source type if need be. */
9697 /* Consider all aligned floating-point types atomic and any aligned types
9698 that are represented by integers no wider than a machine word. */
9699 scalar_int_mode int_mode;
9706 /* For the moment, also allow anything that has an alignment equal to its
9707 size and which is smaller than a word. */
9718 {
9719 unsigned char pragma_id
9724 {
9727 }
9728 }
9736 else
9739 }
9741 /* Return true if TYPE is suitable for a type-generic atomic builtin. */
9743 static bool
9745 {
9750 scalar_int_mode imode;
9755 }
9757 /* Return the GCC atomic builtin based on CODE and sized for TYPE. */
9759 static tree
9761 {
9766 }
9768 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
9769 on the Ada/builtin argument lists for the INB binding. */
9771 static bool
9773 {
9779 /* Sequence position of the last argument we checked. */
9783 {
9787 /* If we've exhausted both lists simultaneously, we're done. */
9791 /* If the internal builtin uses a variable list, accept anything. */
9795 /* If we're done with the Ada args and not with the internal builtin
9796 args, or the other way around, complain. */
9798 {
9801 }
9804 {
9808 }
9810 /* Otherwise, check that types match for the current argument. */
9811 argpos++;
9813 {
9814 /* For vector builtins, issue an error to avoid an ICE. */
9816 post_error_ne_num
9819 else
9820 post_error_ne_num
9824 }
9829 }
9832 }
9834 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
9835 on the Ada/builtin return values for the INB binding. */
9837 static bool
9839 {
9843 /* Accept function imported as procedure, common and convenient. */
9847 /* Check return types compatibility otherwise. Note that this
9848 handles void/void as well. */
9850 {
9851 /* For vector builtins, issue an error to avoid an ICE. */
9855 else
9859 }
9862 }
9864 /* Check and return whether the Ada and gcc builtin profiles bound by INB are
9865 compatible. Issue relevant warnings when they are not.
9867 This is intended as a light check to diagnose the most obvious cases, not
9868 as a full fledged type compatibility predicate. It is the programmer's
9869 responsibility to ensure correctness of the Ada declarations in Imports,
9870 especially when binding straight to a compiler internal. */
9872 static bool
9874 {
9875 /* Check compatibility on return values and argument lists, each responsible
9876 for posting warnings as appropriate. Ensure use of the proper sloc for
9877 this purpose. */
9890 }
9892 /* Return a FIELD_DECL node modeled on OLD_FIELD. FIELD_TYPE is its type
9893 and RECORD_TYPE is the type of the parent. If SIZE is nonzero, it is the
9894 specified size for this field. POS_LIST is a position list describing
9895 the layout of OLD_FIELD and SUBST_LIST a substitution list to be applied
9896 to this layout. */
9898 static tree
9902 {
9914 /* If the position is now a constant, we can set it as the position of the
9915 field when we make it. Otherwise, we need to deal with it specially. */
9918 else
9921 new_field
9927 {
9929 /* Finalize the position. */
9938 }
9946 }
9948 /* Create the REP part of RECORD_TYPE with REP_TYPE. If MIN_SIZE is nonzero,
9949 it is the minimal size the REP_PART must have. */
9951 static tree
9953 {
9954 tree field;
9964 }
9966 /* Return the REP part of RECORD_TYPE, if any. Otherwise return NULL. */
9968 static tree
9970 {
9973 /* The REP part is the first field, internal, another record, and its name
9974 starts with an 'R'. */
9982 }
9984 /* Return the variant part of RECORD_TYPE, if any. Otherwise return NULL. */
9986 tree
9988 {
9989 tree field;
9991 /* The variant part is the only internal field that is a qualified union. */
9998 }
10000 /* Return a new variant part modeled on OLD_VARIANT_PART. VARIANT_LIST is
10001 the list of variants to be used and RECORD_TYPE is the type of the parent.
10002 POS_LIST is a position list describing the layout of fields present in
10003 OLD_VARIANT_PART and SUBST_LIST a substitution list to be applied to this
10004 layout. DEBUG_INFO_P is true if we need to write debug information. */
10006 static tree
10012 {
10020 /* First create the type of the variant part from that of the old one. */
10026 /* If the position of the variant part is constant, subtract it from the
10027 size of the type of the parent to get the new size. This manual CSE
10028 reduces the code size when not optimizing. */
10032 {
10042 first_bit));
10045 }
10046 else
10049 /* Now finish up the new variants and populate the union type. */
10051 {
10055 /* Skip variants that don't belong to this nesting level. */
10059 /* Retrieve the list of fields already added to the new variant. */
10063 /* If the old variant had a variant subpart, we need to create a new
10064 variant subpart and add it to the field list. */
10068 {
10069 tree new_variant_subpart
10072 debug_info_p);
10075 }
10077 /* Finish up the new variant and create the field. */
10082 new_field
10090 }
10092 /* Finish up the union type and create the variant part. Note that we don't
10093 reverse the field list because VARIANT_LIST has been traversed in reverse
10094 order. */
10099 new_variant_part
10105 /* With multiple discriminants it is possible for an inner variant to be
10106 statically selected while outer ones are not; in this case, the list
10107 of fields of the inner variant is not flattened and we end up with a
10108 qualified union with a single member. Drop the useless container. */
10110 {
10119 }
10122 }
10124 /* Copy the size (and alignment and alias set) from OLD_TYPE to NEW_TYPE,
10125 which are both RECORD_TYPE, after applying the substitutions described
10126 in SUBST_LIST. */
10128 static void
10131 {
10155 SET_TYPE_ADA_SIZE
10159 /* Finalize the size. */
10162 }
10164 /* Return true if DISC is a stored discriminant of RECORD_TYPE. */
10168 {
10175 else
10177 }
10179 /* Copy the layout from {GNAT,GNU}_OLD_TYPE to {GNAT,GNU}_NEW_TYPE, which are
10180 both record types, after applying the substitutions described in SUBST_LIST.
10181 DEBUG_INFO_P is true if we need to write debug information for NEW_TYPE. */
10183 static void
10185 Entity_Id gnat_old_type,
10186 tree gnu_new_type,
10187 tree gnu_old_type,
10190 {
10197 /* Look for REP and variant parts in the old type. */
10201 /* If there is a variant part, we must compute whether the constraints
10202 statically select a particular variant. If so, we simply drop the
10203 qualified union and flatten the list of fields. Otherwise we will
10204 build a new qualified union for the variants that are still relevant. */
10206 {
10211 gnu_variant_list
10213 is_subtype
10214 ? Empty
10215 : Variant_Part
10217 subst_list,
10218 vNULL);
10220 /* If all the qualifiers are unconditionally true, the innermost variant
10221 is statically selected. */
10225 {
10228 }
10230 /* Otherwise, create the new variants. */
10233 {
10236 tree suffix
10246 }
10247 }
10248 else
10249 {
10252 }
10254 /* Make a list of fields and their position in the old type. */
10255 tree gnu_pos_list
10261 /* Now go down every component in the new type and compute its size and
10262 position from those of the component in the old type and the stored
10263 constraints of the new type. */
10276 {
10286 /* If the type is the same, retrieve the GCC type from the
10287 old field to take into account possible adjustments. */
10290 else
10293 /* If there was a component clause, the field types must be the same
10294 for the old and new types, so copy the data from the old field to
10295 avoid recomputation here. Also if the field is justified modular
10296 and the optimization in gnat_to_gnu_field was applied. */
10302 {
10305 }
10307 /* If the old field was packed and of constant size, we have to get the
10308 old size here as it might differ from what the Etype conveys and the
10309 latter might overlap with the following field. Try to arrange the
10310 type for possible better packing along the way. */
10313 {
10319 }
10321 else
10324 /* If the context of the old field is the old type or its REP part,
10325 put the field directly in the new type; otherwise look up the
10326 context in the variant list and put the field either in the new
10327 type if there is a selected variant or in one new variant. */
10331 else
10332 {
10334 tree rep_part;
10344 else
10345 /* The front-end may pass us zombie components if it fails to
10346 recognize that a constrain statically selects a particular
10347 variant. Discard them. */
10349 }
10351 /* Now create the new field modeled on the old one. */
10352 gnu_field
10358 /* If the context is a variant, put it in the new variant directly. */
10360 {
10362 {
10365 }
10366 else
10367 {
10370 }
10371 }
10373 /* To match the layout crafted in components_to_record, if this is
10374 the _Tag or _Parent field, put it before any other fields. */
10378 /* Similarly, if this is the _Controller field, put it before the
10379 other fields except for the _Tag or _Parent field. */
10381 {
10384 }
10386 /* Otherwise, put it after the other fields. */
10387 else
10388 {
10390 {
10395 }
10396 else
10397 {
10400 }
10401 }
10403 /* For a stored discriminant in a derived type, replace the field. */
10405 {
10408 }
10409 else
10411 }
10413 /* Put the fields with fixed position in order of increasing position. */
10417 /* Put the fields with variable position at the end. */
10421 /* If there is a variant list and no selected variant, we need to create the
10422 nest of variant parts from the old nest. */
10424 {
10428 /* Same processing as above for the fields of each variant. */
10430 {
10437 }
10439 tree new_variant_part
10445 }
10450 /* If NEW_TYPE is a subtype, it inherits all the attributes from OLD_TYPE.
10451 Otherwise sizes and alignment must be computed independently. */
10455 /* Now go through the entities again looking for itypes that we have not yet
10456 elaborated (e.g. Etypes of fields that have Original_Components). */
10465 }
10467 /* Associate to the implementation type of a packed array type specified by
10468 GNU_TYPE, which is the translation of GNAT_ENTITY, the original array type
10469 if it has been translated. This association is a parallel type for GNAT
10470 encodings or a debug type for standard DWARF. Note that for standard DWARF,
10471 we also want to get the original type name and therefore we return it. */
10473 static tree
10475 {
10476 const Entity_Id gnat_original_array_type
10478 tree gnu_original_array_type;
10491 {
10494 }
10495 else
10496 {
10503 }
10504 }
10506 /* Given a type T, a FIELD_DECL F, and a replacement value R, return an
10507 equivalent type with adjusted size expressions where all occurrences
10508 of references to F in a PLACEHOLDER_EXPR have been replaced by R.
10510 The function doesn't update the layout of the type, i.e. it assumes
10511 that the substitution is purely formal. That's why the replacement
10512 value R must itself contain a PLACEHOLDER_EXPR. */
10514 tree
10516 {
10517 tree nt;
10522 {
10528 /* First the domain types of arrays. */
10531 {
10543 SET_TYPE_INDEX_TYPE
10547 }
10549 /* Then the subtypes. */
10552 {
10564 }
10577 /* These should never show up here. */
10581 {
10601 }
10606 {
10608 tree field;
10610 /* Start out with no fields, make new fields, and chain them
10611 in. If we haven't actually changed the type of any field,
10612 discard everything we've done and return the old type. */
10617 {
10622 {
10625 }
10629 {
10632 }
10634 /* Do the substitution inside the qualifier, if any. */
10636 {
10639 {
10642 }
10643 }
10650 }
10660 }
10664 }
10665 }
10667 /* Return the RM size of GNU_TYPE. This is the actual number of bits
10668 needed to represent the object. */
10670 tree
10672 {
10673 /* For integral types, we store the RM size explicitly. */
10677 /* If the type contains a template, return the padded size of the template
10678 plus the RM size of the actual data. */
10681 return
10686 /* For record or union types, we store the size explicitly. */
10692 /* For other types, this is just the size. */
10694 }
10696 /* Return the name to be used for GNAT_ENTITY. If a type, create a
10697 fully-qualified name, possibly with type information encoding.
10698 Otherwise, return the name. */
10702 {
10705 }
10707 tree
10709 {
10712 }
10714 /* Return an identifier representing the external name to be used for
10715 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
10716 and the specified suffix. */
10718 tree
10720 {
10728 /* A variable using the Stdcall convention lives in a DLL. We adjust
10729 its name to use the jump table, the _imp__NAME contains the address
10730 for the NAME variable. */
10733 {
10739 }
10742 }
10744 /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
10745 string, return a new IDENTIFIER_NODE that is the concatenation of
10746 the name followed by "___" and the specified suffix. */
10748 tree
10750 {
10757 }
10759 /* Initialize the data structures of the decl.cc module. */
10761 void
10763 {
10764 /* Initialize the cache of annotated values. */
10767 /* Initialize the association of dummy types with subprograms. */
10769 }
10771 /* Destroy the data structures of the decl.cc module. */
10773 void
10775 {
10776 /* Destroy the cache of annotated values. */
10780 /* Destroy the association of dummy types with subprograms. */
10783 }