| blob | 5b3a3b4961b422682d87c59bd7df2b18981f6997 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2024, 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 ****************************************************************************/
57 /* The "stdcall" convention is really supported on 32-bit x86/Windows only.
58 The following macro is a helper to avoid having to check for a Windows
59 specific attribute throughout this unit. */
61 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
62 #ifdef TARGET_64BIT
63 #define Has_Stdcall_Convention(E) \
64 (!TARGET_64BIT && Convention (E) == Convention_Stdcall)
65 #else
66 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
67 #endif
68 #else
69 #define Has_Stdcall_Convention(E) 0
70 #endif
74 /* Stack realignment is necessary for functions with foreign conventions when
75 the ABI doesn't mandate as much as what the compiler assumes - that is, up
76 to PREFERRED_STACK_BOUNDARY.
78 Such realignment can be requested with a dedicated function type attribute
79 on the targets that support it. We define FOREIGN_FORCE_REALIGN_STACK to
80 characterize the situations where the attribute should be set. We rely on
81 compiler configuration settings for 'main' to decide. */
83 #ifdef MAIN_STACK_BOUNDARY
84 #define FOREIGN_FORCE_REALIGN_STACK \
85 (MAIN_STACK_BOUNDARY < PREFERRED_STACK_BOUNDARY)
86 #else
87 #define FOREIGN_FORCE_REALIGN_STACK 0
88 #endif
90 /* The largest TYPE_ARRAY_MAX_SIZE value we set on an array type.
91 It's an artibrary limit (256 MB) above which we consider that
92 the allocation is essentially unbounded. */
94 #define TYPE_ARRAY_SIZE_LIMIT (1 << 28)
96 struct incomplete
97 {
99 tree old_type;
100 Entity_Id full_type;
101 };
103 /* These variables are used to defer recursively expanding incomplete types
104 while we are processing a record, an array or a subprogram type. */
108 /* This variable is used to delay expanding types coming from a limited with
109 clause and completed Taft Amendment types until the end of the spec. */
113 tree discriminant;
114 tree replacement;
119 /* The type of the variant. */
120 tree type;
122 /* The associated field. */
123 tree field;
125 /* The value of the qualifier. */
126 tree qual;
128 /* The type of the variant after transformation. */
129 tree new_type;
131 /* The auxiliary data. */
132 tree aux;
136 /* A map used to cache the result of annotate_value. */
138 {
141 {
143 }
147 {
149 }
151 static int
153 {
155 }
156 };
160 /* A map used to associate a dummy type with a list of subprogram entities. */
162 {
165 };
168 {
171 {
173 }
177 {
179 }
181 static int
183 {
185 }
186 };
223 tree *);
251 /* The relevant constituents of a subprogram binding to a GCC builtin. Used
252 to pass around calls performing profile compatibility checks. */
262 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
263 entity, return the equivalent GCC tree for that entity (a ..._DECL node)
264 and associate the ..._DECL node with the input GNAT defining identifier.
266 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
267 initial value (in GCC tree form). This is optional for a variable. For
268 a renamed entity, GNU_EXPR gives the object being renamed.
270 DEFINITION is true if this call is intended for a definition. This is used
271 for separate compilation where it is necessary to know whether an external
272 declaration or a definition must be created if the GCC equivalent was not
273 created previously. */
275 tree
277 {
278 /* The construct that declared the entity. */
280 /* The object that the entity renames, if any. */
282 /* The kind of the entity. */
284 /* True if this is a type. */
286 /* True if this is an artificial entity. */
288 /* True if debug info is requested for this entity. */
290 /* True if this entity is to be considered as imported. */
291 const bool imported_p
293 /* True if this entity has a foreign convention. */
295 /* For a type, contains the equivalent GNAT node to be used in gigi. */
297 /* For a subtype, contains the GNAT node to be used as cloned subtype. */
299 /* Temporary used to walk the GNAT tree. */
300 Entity_Id gnat_temp;
301 /* Contains the GCC DECL node which is equivalent to the input GNAT node.
302 This node will be associated with the GNAT node by calling at the end
303 of the `switch' statement. */
305 /* Contains the GCC type to be used for the GCC node. */
307 /* Contains the GCC size tree to be used for the GCC node. */
309 /* Contains the GCC name to be used for the GCC node. */
310 tree gnu_entity_name;
311 /* True if we have already saved gnu_decl as a GNAT association. This can
312 also be used to purposely avoid making such an association but this use
313 case ought not to be applied to types because it can break the deferral
314 mechanism implemented for access types. */
316 /* True if we incremented defer_incomplete_level. */
318 /* True if we incremented force_global. */
320 /* True if we should check to see if elaborated during processing. */
322 /* True if we made GNU_DECL and its type here. */
324 /* Size and alignment of the GCC node, if meaningful. */
326 /* Contains the list of attributes directly attached to the entity. */
329 /* Since a use of an itype is a definition, process it as such if it is in
330 the main unit, except for E_Access_Subtype because it's actually a use
331 of its base type, and for E_Class_Wide_Subtype with an Equivalent_Type
332 because it's actually a use of the latter type. */
334 && is_type
341 {
342 /* Unless it's for an anonymous access type, whose scope is irrelevant,
343 ensure that we are in a subprogram mentioned in the Scope chain of
344 this entity, our current scope is global, or we encountered a task
345 or entry (where we can't currently accurately check scoping). */
347 || !current_function_decl
349 {
352 }
357 {
370 && (current_function_decl
372 {
375 }
376 }
378 /* This abort means the itype has an incorrect scope, i.e. that its
379 scope does not correspond to the subprogram it is first used in. */
381 }
383 /* If we've already processed this entity, return what we got last time.
384 If we are defining the node, we should not have already processed it.
385 In that case, we will abort below when we try to save a new GCC tree
386 for this object. We also need to handle the case of getting a dummy
387 type when a Full_View exists but be careful so as not to trigger its
388 premature elaboration. Likewise for a cloned subtype without its own
389 freeze node, which typically happens when a generic gets instantiated
390 on an incomplete or private type. */
393 {
402 {
403 gnu_decl
408 }
417 {
418 gnu_decl
423 }
426 }
428 /* If this is a numeric or enumeral type, or an access type, a nonzero Esize
429 must be specified unless it was specified by the programmer. Exceptions
430 are for access-to-protected-subprogram types and all access subtypes, as
431 another GNAT type is used to lay out the GCC type for them, as well as
432 access-to-subprogram types if front-end unnesting is enabled. */
447 /* The RM size must be specified for all discrete and fixed-point types. */
451 /* If we get here, it means we have not yet done anything with this entity.
452 If we are not defining it, it must be a type or an entity that is defined
453 elsewhere or externally, otherwise we should have defined it already.
455 In other words, the failure of this assertion typically arises when a
456 reference to an entity (type or object) is made before its declaration,
457 either directly or by means of a freeze node which is incorrectly placed.
458 This can also happen for an entity referenced out of context, for example
459 a parameter outside of the subprogram where it is declared. GNAT_ENTITY
460 is the N_Defining_Identifier of the entity, the problematic N_Identifier
461 being the argument passed to Identifier_to_gnu in the parent frame.
463 One exception is for an entity, typically an inherited operation, which is
464 a local alias for the parent's operation. It is neither defined, since it
465 is an inherited operation, nor public, since it is declared in the current
466 compilation unit, so we test Is_Public on the Alias entity instead. */
468 || is_type
478 /* Get the name of the entity and set up the line number and filename of
479 the original definition for use in any decl we make. Make sure we do
480 not inherit another source location. */
485 /* For cases when we are not defining (i.e., we are referencing from
486 another compilation unit) public entities, show we are at global level
487 for the purpose of computing scopes. Don't do this for components or
488 discriminants since the relevant test is whether or not the record is
489 being defined. */
497 /* Handle any attributes directly attached to the entity. */
501 /* Do some common processing for types. */
503 {
504 /* Compute the equivalent type to be used in gigi. */
507 /* Machine_Attributes on types are expected to be propagated to
508 subtypes. The corresponding Gigi_Rep_Items are only attached
509 to the first subtype though, so we handle the propagation here. */
515 /* Compute a default value for the size of an elementary type. */
517 {
524 max_esize
528 else
533 }
534 }
537 {
540 {
541 /* The GNAT record where the component was defined. */
544 /* If the entity is a discriminant of an extended tagged type used to
545 rename a discriminant of the parent type, return the latter. */
549 {
550 gnu_decl
555 }
557 /* If the entity is an inherited component (in the case of extended
558 tagged record types), just return the original entity, which must
559 be a FIELD_DECL. Likewise for discriminants. If the entity is a
560 non-stored discriminant (in the case of derived untagged record
561 types), return the stored discriminant it renames. */
564 {
565 gnu_decl
568 /* GNU_DECL contains a PLACEHOLDER_EXPR for discriminants. */
572 }
574 /* Otherwise, if we are not defining this and we have no GCC type
575 for the containing record, make one for it. Then we should
576 have made our own equivalent. */
578 {
579 /* ??? If this is in a record whose scope is a protected
580 type and we have an Original_Record_Component, use it.
581 This is a workaround for major problems in protected type
582 handling. */
586 {
587 gnu_decl
591 }
592 else
593 {
596 }
600 }
602 /* Here we have no GCC type and this is a reference rather than a
603 definition. This should never happen. Most likely the cause is
604 reference before declaration in the GNAT tree for gnat_entity. */
606 }
610 {
616 /* All references are supposed to be folded in the front-end. */
622 /* Build a CONST_DECL for debugging purposes exclusively. */
623 gnu_decl
628 }
632 /* Ignore constant definitions already marked with the error node. See
633 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
637 {
640 }
642 /* Ignore deferred constant definitions without address clause since
643 they are processed fully in the front-end. If No_Initialization
644 is set, this is not a deferred constant but a constant whose value
645 is built manually. And constants that are renamings are handled
646 like variables. */
648 && !gnu_expr
652 {
656 }
658 /* If this is a use of a deferred constant without address clause,
659 get its full definition. */
663 {
664 gnu_decl
668 }
670 /* If we have a constant that we are not defining, get the expression it
671 was defined to represent. This is necessary to avoid generating dumb
672 elaboration code in simple cases, and we may throw it away later if it
673 is not a constant. But do not do it for dispatch tables because they
674 are only referenced indirectly and we need to have a consistent view
675 of the exported and of the imported declarations of the tables from
676 external units for them to be properly merged in LTO mode. Moreover
677 simply do not retrieve the expression if it is an allocator because
678 the designated type might still be dummy at this point. Note that we
679 invoke gnat_to_gnu_external and not gnat_to_gnu because the expression
680 may contain N_Expression_With_Actions nodes and thus declarations of
681 objects from other units that we need to discard. Note also that we
682 need to do it even if we are only annotating types, so as to be able
683 to validate representation clauses using constants. */
692 /* ... fall through ... */
698 {
701 /* Always create a variable for volatile objects and variables seen
702 constant but with a Linker_Section pragma. */
703 bool const_flag
715 /* We implement RM 13.3(19) for exported and imported (non-constant)
716 objects by making them volatile. */
717 bool volatile_flag
725 /* We need to translate the renamed object even though we are only
726 referencing the renaming. But it may contain a call for which
727 we'll generate a temporary to hold the return value and which
728 is part of the definition of the renaming, so discard it. */
730 {
734 else
736 }
738 /* Get the type after elaborating the renamed object. */
741 else
744 /* For a debug renaming declaration, build a debug-only entity. */
746 {
747 /* Force a non-null value to make sure the symbol is retained. */
751 integer_minus_one_node));
759 }
761 /* If this is a loop variable, its type should be the base type.
762 This is because the code for processing a loop determines whether
763 a normal loop end test can be done by comparing the bounds of the
764 loop against those of the base type, which is presumed to be the
765 size used for computation. But this is not correct when the size
766 of the subtype is smaller than the type. */
770 /* If this is a simple constant, strip the qualifiers from its type,
771 since the constant represents only its value. */
775 /* Reject non-renamed objects whose type is an unconstrained array or
776 any object whose type is a dummy type or void. */
781 {
784 force_global--;
786 }
788 /* If an alignment is specified, use it if valid. Note that exceptions
789 are objects but don't have an alignment and there is also no point in
790 setting it for an address clause, since the final type of the object
791 will be a reference type. */
798 /* Likewise, if a size is specified, use it if valid. */
800 gnu_size
805 {
806 gnu_type
812 }
814 /* If this object has self-referential size, it must be a record with
815 a default discriminant. We are supposed to allocate an object of
816 the maximum size in this case, unless it is a constant with an
817 initializing expression, in which case we can get the size from
818 that. Note that the resulting size may still be a variable, so
819 this may end up with an indirect allocation. */
822 {
824 {
828 {
829 /* If the initializing expression is itself a constant,
830 despite having a nominal type with self-referential
831 size, we can get the size directly from it. */
833 && TYPE_IS_PADDING_P
837 || DECL_READONLY_ONCE_ELAB
839 {
842 }
843 else
844 {
845 gnu_size
847 gnu_expr);
848 gnu_ada_size
850 gnu_expr);
851 }
852 }
853 }
854 /* We may have no GNU_EXPR because No_Initialization is
855 set even though there's an Expression. */
859 {
860 tree gnu_expr_type
864 }
865 else
866 {
868 /* We can be called on unconstrained arrays in this mode. */
872 }
874 /* If the size isn't constant and we are at global level, call
875 elaborate_expression_1 to make a variable for it rather than
876 calculating it each time. */
880 }
882 /* If the size is zero byte, make it one byte since some linkers have
883 troubles with zero-sized objects. If the object will have a
884 template, that will make it nonzero so don't bother. Also avoid
885 doing that for an object renaming or an object with an address
886 clause, as we would lose useful information on the view size
887 (e.g. for null array slices) and we are not allocating the object
888 here anyway. */
900 /* If this is an object with no specified size and alignment, and
901 if either it is full access or we are not optimizing alignment for
902 space and it is composite and not an exception, an Out parameter
903 or a reference to another object, and the size of its type is a
904 constant, set the alignment to the smallest one which is not
905 smaller than the size, with an appropriate cap. */
915 && !imported_p
921 /* If the object is set to have atomic components, find the component
922 type and validate it.
924 ??? Note that we ignore Has_Volatile_Components on objects; it's
925 not at all clear what to do in that case. */
927 {
936 }
938 /* If this is an array allocated with its bounds, make a type that
939 includes the template. We will either allocate it or create a
940 variable of that type, see below. */
943 {
945 /* Make sure to have an array type for the template. */
948 gnu_type
950 gnu_type,
953 debug_info_p);
954 }
956 /* ??? If this is an object of CW type initialized to a value, try to
957 ensure that the object is sufficient aligned for this value, but
958 without pessimizing the allocation. This is a kludge necessary
959 because we don't support dynamic alignment. */
966 #ifdef MINIMUM_ATOMIC_ALIGNMENT
967 /* If the size is a constant and no alignment is specified, force
968 the alignment to be the minimum valid atomic alignment. The
969 restriction on constant size avoids problems with variable-size
970 temporaries; if the size is variable, there's no issue with
971 atomic access. Also don't do this for a constant, since it isn't
972 necessary and can interfere with constant replacement. Finally,
973 do not do it for Out parameters since that creates an
974 size inconsistency with In parameters. */
984 #endif
986 /* Do not take into account aliased adjustments or alignment promotions
987 to compute the size of the object. */
990 /* If the object is aliased, of a constrained nominal subtype and its
991 size might be zero at run time, we force at least the unit size. */
999 /* Make a new type with the desired size and alignment, if needed. */
1001 {
1007 /* If the nominal subtype of the object is unconstrained and its
1008 size is not fixed, compute the Ada size from the Ada size of
1009 the subtype and/or the expression; this will make it possible
1010 for gnat_type_max_size to easily compute a maximum size. */
1014 /* If a padding record was made, declare it now since it will
1015 never be declared otherwise. This is necessary to ensure
1016 that its subtrees are properly marked. */
1020 }
1022 /* Now check if the type of the object allows atomic access. */
1026 /* If this is a renaming, avoid as much as possible to create a new
1027 object. However, in some cases, creating it is required because
1028 renaming can be applied to objects that are not names in Ada.
1029 This processing needs to be applied to the raw expression so as
1030 to make it more likely to rename the underlying object. */
1032 {
1033 /* If the renamed object had padding, strip off the reference to
1034 the inner object and reset our type. */
1037 /* Strip useless conversions around the object. */
1039 {
1042 }
1044 /* Or else, if the renamed object has an unconstrained type with
1045 default discriminant, use the padded type. */
1049 /* If this is a constant renaming stemming from a function call,
1050 treat it as a normal object whose initial value is what is being
1051 renamed. RM 3.3 says that the result of evaluating a function
1052 call is a constant object. Therefore, it can be the inner
1053 object of a constant renaming and the renaming must be fully
1054 instantiated, i.e. it cannot be a reference to (part of) an
1055 existing object. And treat other rvalues the same way. */
1059 /* Expand_Dispatching_Call can prepend a comparison of the tags
1060 before the call to "=". */
1071 /* We need to detect the case where a temporary is created to
1072 hold the return value, since we cannot safely rename it at
1073 top level because it lives only in the elaboration routine.
1074 But, at a lower level, an object initialized by a function
1075 call may be (implicitly) renamed as this temporary by the
1076 front-end and, in this case, we cannot make a copy. */
1080 /* We also need to detect the case where the front-end creates
1081 a dangling 'reference to a function call at top level and
1082 substitutes it in the renaming, for example:
1084 q__b : boolean renames r__f.e (1);
1086 can be rewritten into:
1088 q__R1s : constant q__A2s := r__f'reference;
1089 [...]
1090 q__b : boolean renames q__R1s.all.e (1);
1092 We cannot safely rename the rewritten expression since the
1093 underlying object lives only in the elaboration routine but,
1094 as above, this cannot be done at a lower level. */
1096 && (inner
1101 ;
1103 /* Otherwise, this is an lvalue being renamed, so it needs to be
1104 elaborated as a reference and substituted for the entity. But
1105 this means that we must evaluate the address of the renaming
1106 in the definition case to instantiate the SAVE_EXPRs. */
1107 else
1108 {
1114 gnu_expr
1118 /* No DECL_EXPR might be created so the expression needs to be
1119 marked manually because it will likely be shared. */
1123 /* This assertion will fail if the renamed object isn't aligned
1124 enough as to make it possible to honor the alignment set on
1125 the renaming. */
1127 {
1128 const unsigned int ralign
1133 }
1135 /* The expression might not be a DECL so save it manually. */
1141 /* If this is only a reference to the entity, we are done. */
1145 /* Otherwise, emit the initialization statement, if any. */
1149 /* If it needs to be materialized for debugging purposes, build
1150 the entity as indirect reference to the renamed object. */
1152 {
1153 /* If this is an array allocated with its bounds, we make
1154 its type a thin reference, the reference counterpart of
1155 a thin pointer, exactly as we would have done in the
1156 non-renaming case below. */
1159 {
1160 tree gnu_array
1163 }
1176 }
1178 /* Otherwise, instantiate the SAVE_EXPRs if needed. */
1183 }
1184 }
1186 /* If we are defining an aliased object whose nominal subtype is
1187 unconstrained, the object is a record that contains both the
1188 template and the object. If there is an initializer, it will
1189 have already been converted to the right type, but we need to
1190 create the template if there is no initializer. */
1192 && !gnu_expr
1195 /* Beware that padding might have been introduced above. */
1198 == RECORD_TYPE
1199 && TYPE_CONTAINS_TEMPLATE_P
1201 {
1202 tree template_field
1210 NULL_TREE);
1213 }
1215 /* Convert the expression to the type of the object if need be. */
1219 /* If this is a pointer that doesn't have an initializing expression,
1220 initialize it to NULL, unless the object is declared imported as
1221 per RM B.1(24). */
1224 && !gnu_expr
1228 /* If we are defining the object and it has an Address clause, we must
1229 either get the address expression from the saved GCC tree for the
1230 object if it has a Freeze node, or elaborate the address expression
1231 here since the front-end has guaranteed that the elaboration has no
1232 effects in this case. */
1234 {
1243 /* Convert the type of the object to a reference type that can
1244 alias everything as per RM 13.3(19). */
1247 gnu_type
1251 const_flag
1257 /* If this is an aliased object with an unconstrained array nominal
1258 subtype, then it can overlay only another aliased object with an
1259 unconstrained array nominal subtype and compatible template. */
1262 {
1266 /* This is the pattern built for a regular object. */
1271 /* This is the pattern built for an overaligned object. */
1274 == PLUS_EXPR
1277 gnu_address
1282 /* We make an exception for an absolute address but we warn
1283 that there is a descriptor at the start of the object. */
1285 {
1288 gnat_entity);
1291 }
1293 else
1294 {
1297 gnat_entity);
1300 }
1301 }
1303 /* If we don't have an initializing expression for the underlying
1304 variable, the initializing expression for the pointer is the
1305 specified address. Otherwise, we have to make a COMPOUND_EXPR
1306 to assign both the address and the initial value. */
1309 else
1310 gnu_expr
1314 NULL_TREE,
1315 gnu_address),
1316 gnu_expr),
1317 gnu_address);
1318 }
1320 /* If it has an address clause and we are not defining it, mark it
1321 as an indirect object. Likewise for Stdcall objects that are
1322 imported. */
1325 {
1326 /* Convert the type of the object to a reference type that can
1327 alias everything as per RM 13.3(19). */
1330 gnu_type
1337 /* No point in taking the address of an initializing expression
1338 that isn't going to be used. */
1341 /* If it has an address clause whose value is known at compile
1342 time, make the object a CONST_DECL. This will avoid a
1343 useless dereference. */
1345 {
1346 Node_Id gnat_address
1350 {
1353 }
1354 }
1355 }
1357 /* If we are at top level and this object is of variable size,
1358 make the actual type a hidden pointer to the real type and
1359 make the initializer be a memory allocation and initialization.
1360 Likewise for objects we aren't defining (presumed to be
1361 external references from other packages), but there we do
1362 not set up an initialization.
1364 If the object's size overflows, make an allocator too, so that
1365 Storage_Error gets raised. Note that we will never free
1366 such memory, so we presume it never will get allocated. */
1369 || !definition
1371 || (gnu_size
1373 size_binop
1375 bitsize_unit_node)),
1377 || !definition
1379 {
1388 /* In case this was an aliased object whose nominal subtype is
1389 unconstrained, the pointer above will be a thin pointer and
1390 build_allocator will automatically make the template.
1392 If we have a template initializer only (that we made above),
1393 pretend there is none and rely on what build_allocator creates
1394 again anyway. Otherwise (if we have a full initializer), get
1395 the data part and feed that to build_allocator.
1397 If we are elaborating a mutable object, tell build_allocator to
1398 ignore a possibly simpler size from the initializer, if any, as
1399 we must allocate the maximum possible size in this case. */
1401 {
1406 {
1407 gnu_alloc_type
1413 else
1414 gnu_expr
1415 = build_component_ref
1419 }
1421 /* Give a warning if the size is constant but too large. */
1423 {
1425 {
1426 post_error
1428 gnat_entity);
1430 gnat_entity);
1431 }
1433 else
1435 gnat_entity);
1436 }
1438 gnu_expr
1441 }
1442 else
1444 }
1446 /* If this object would go into the stack and has an alignment larger
1447 than the largest stack alignment the back-end can honor, resort to
1448 a variable of "aligning type". */
1451 && !imported_p
1452 && !static_flag
1454 {
1455 /* Create the new variable. No need for extra room before the
1456 aligned field as this is in automatic storage. */
1457 tree gnu_new_type
1461 tree gnu_new_var
1466 gnat_entity);
1468 /* Initialize the aligned field if we have an initializer. */
1470 add_stmt_with_node
1472 build_component_ref
1475 gnu_expr),
1476 gnat_entity);
1478 /* And setup this entity as a reference to the aligned field. */
1480 gnu_expr
1481 = build_unary_op
1491 }
1493 /* If this is an aggregate constant initialized to a constant, force it
1494 to be statically allocated. This saves an initialization copy. */
1496 && const_flag
1497 && gnu_expr
1506 /* If this is an array allocated with its bounds, we make its type a
1507 thin reference, i.e. the reference counterpart of a thin pointer,
1508 so that it points to the array part. This is aimed at making it
1509 easier for the debugger to decode the object. Note that we have
1510 to do it this late because of the couple of allocation adjustments
1511 that might be made above. */
1514 {
1515 /* In case the object with the template has already been allocated
1516 just above, we have nothing to do here. */
1518 {
1519 /* This variable is a GNAT encoding used by Workbench: let it
1520 go through the debugging information but mark it as
1521 artificial: users are not interested in it. */
1522 tree gnu_unc_var
1538 }
1541 gnu_type
1543 }
1545 /* Convert the expression to the type of the object if need be. */
1549 /* If this name is external or a name was specified, use it, but don't
1550 use the Interface_Name with an address clause (see cd30005). */
1556 /* Deal with a pragma Linker_Section on a constant or variable. */
1562 /* Now create the variable or the constant and set various flags. */
1563 gnu_decl
1569 gnat_entity);
1574 /* If we are defining an Out parameter and optimization isn't enabled,
1575 create a fake PARM_DECL for debugging purposes and make it point to
1576 the VAR_DECL. Suppress debug info for the latter but make sure it
1577 will live in memory so that it can be accessed from within the
1578 debugger through the PARM_DECL. */
1580 && definition
1581 && debug_info_p
1582 && !optimize
1584 {
1591 }
1593 /* If this is a loop parameter, set the corresponding flag. */
1597 /* If this is a constant and we are defining it or it generates a real
1598 symbol at the object level and we are referencing it, we may want
1599 or need to have a true variable to represent it:
1600 - if the constant is public and not overlaid on something else,
1601 - if its address is taken,
1602 - if it is aliased,
1603 - if optimization isn't enabled, for debugging purposes. */
1610 {
1611 tree gnu_corr_var
1620 }
1622 /* If this is a constant, even if we don't need a true variable, we
1623 may need to avoid returning the initializer in every case. That
1624 can happen for the address of a (constant) constructor because,
1625 upon dereferencing it, the constructor will be reinjected in the
1626 tree, which may not be valid in every case; see lvalue_required_p
1627 for more details. */
1631 /* If this is a local variable with non-BLKmode and aggregate type,
1632 and optimization isn't enabled, then force it in memory so that
1633 a register won't be allocated to it with possible subparts left
1634 uninitialized and reaching the register allocator. */
1644 /* Back-annotate Esize and Alignment of the object if not already
1645 known. Note that we pick the values of the type, not those of
1646 the object, to shield ourselves from low-level platform-dependent
1647 adjustments like alignment promotion. This is both consistent with
1648 all the treatment above, where alignment and size are set on the
1649 type of the object and not on the object directly, and makes it
1650 possible to support all confirming representation clauses. */
1652 used_by_ref);
1653 }
1657 /* Return a TYPE_DECL for "void" that we previously made. */
1662 /* A special case: for the types Character and Wide_Character in
1663 Standard, we do not list all the literals. So if the literals
1664 are not specified, make this an integer type. */
1666 {
1669 else
1673 /* Set TYPE_STRING_FLAG for Character and Wide_Character types.
1674 This is needed by the DWARF-2 back-end to distinguish between
1675 unsigned integer types and character types. */
1678 /* This flag is needed by the call just below. */
1682 }
1683 else
1684 {
1685 /* We have a list of enumeral constants in First_Literal. We make a
1686 CONST_DECL for each one and build into GNU_LITERAL_LIST the list
1687 to be placed into TYPE_FIELDS. Each node is itself a TREE_LIST
1688 whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
1689 value of the literal. But when we have a regular boolean type, we
1690 simplify this a little by using a BOOLEAN_TYPE. */
1695 Entity_Id gnat_literal;
1697 /* Boolean types with foreign convention have precision 1. */
1712 {
1713 tree gnu_value
1715 /* Do not generate debug info for individual enumerators. */
1716 tree gnu_literal
1722 gnu_list
1724 }
1729 /* Note that the bounds are updated at the end of this function
1730 to avoid an infinite recursion since they refer to the type. */
1732 }
1736 /* For integer types, just make a signed type the appropriate number
1737 of bits. */
1743 {
1744 /* Small_Value is the scale factor. */
1750 /* When encoded as 1/2**N or 1/10**N, describe the scale factor as a
1751 binary or decimal scale: it is easier to read for humans. */
1755 {
1756 tree base
1758 tree exponent
1761 scale_factor
1763 integer_one_node,
1766 }
1768 /* Use the arbitrary scale factor description. Note that we support
1769 a Small_Value whose magnitude is larger than 64-bit even on 32-bit
1770 platforms, so we unconditionally use a (dummy) 128-bit type. */
1771 else
1772 {
1779 scale_factor
1781 }
1785 }
1789 {
1790 /* Packed Array Impl. Types are supposed to be subtypes only. */
1793 /* For modular types, make the unsigned type of the proper number
1794 of bits and then set up the modulus, if required. */
1797 /* Get the modulus in this type. If the modulus overflows, assume
1798 that this is because it was equal to 2**Esize. Note that there
1799 is no overflow checking done on unsigned types, so we detect the
1800 overflow by looking for a modulus of zero, which is invalid. */
1803 /* If the modulus is not 2**Esize, then this also means that the upper
1804 bound of the type, i.e. modulus - 1, is not maximal, so we create an
1805 extra subtype to carry it and set the modulus on the base type. */
1807 {
1813 gnu_type
1815 gnu_high);
1816 }
1817 }
1829 /* For integral subtypes, we make a new INTEGER_TYPE. Note that we do
1830 not want to call create_range_type since we would like each subtype
1831 node to be distinct. ??? Historically this was in preparation for
1832 when memory aliasing is implemented, but that's obsolete now given
1833 the call to relate_alias_sets below.
1835 The TREE_TYPE field of the INTEGER_TYPE points to the base type;
1836 this fact is used by the arithmetic conversion functions.
1838 We elaborate the Ancestor_Subtype if it is not in the current unit
1839 and one of our bounds is non-static. We do this to ensure consistent
1840 naming in the case where several subtypes share the same bounds, by
1841 elaborating the first such subtype first, thus using its name. */
1850 /* Set the precision to the Esize except for bit-packed arrays. */
1854 /* Boolean types with foreign convention have precision 1. */
1856 {
1862 }
1863 /* First subtypes of Character are treated as Character; otherwise
1864 this should be an unsigned type if the base type is unsigned or
1865 if the lower bound is constant and non-negative or if the type
1866 is biased. However, even if the lower bound is constant and
1867 non-negative, we use a signed type for a subtype with the same
1868 size as its signed base type, because this eliminates useless
1869 conversions to it and gives more leeway to the optimizer; but
1870 this means that we will need to explicitly test for this case
1871 when we change the representation based on the RM size. */
1883 else
1887 SET_TYPE_RM_MIN_VALUE
1890 debug_info_p));
1892 SET_TYPE_RM_MAX_VALUE
1895 debug_info_p));
1901 /* Do the same processing for Character subtypes as for types. */
1904 {
1909 }
1911 /* Inherit our alias set from what we're a subtype of. Subtypes
1912 are not different types and a pointer can designate any instance
1913 within a subtype hierarchy. */
1916 /* One of the above calls might have caused us to be elaborated,
1917 so don't blow up if so. */
1919 {
1922 }
1924 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
1928 discrete_type:
1930 /* We have to handle clauses that under-align the type specially. */
1933 && Present
1936 {
1940 }
1942 /* If the type we are dealing with represents a bit-packed array,
1943 we need to have the bits left justified on big-endian targets
1944 and right justified on little-endian targets. We also need to
1945 ensure that when the value is read (e.g. for comparison of two
1946 such values), we only get the good bits, since the unused bits
1947 are uninitialized. Both goals are accomplished by wrapping up
1948 the modular type in an enclosing record type. */
1950 {
1956 /* Make the original array type a parallel/debug type. */
1958 {
1959 tree gnu_name
1961 gnat_entity);
1964 }
1966 /* Set the RM size before wrapping up the original type. */
1970 /* Create a stripped-down declaration, mainly for debugging. */
1972 gnat_entity);
1974 /* Now save it and build the enclosing record type. */
1985 /* Propagate the alignment of the modular type to the record type,
1986 unless there is an alignment clause that under-aligns the type.
1987 This means that bit-packed arrays are given "ceil" alignment for
1988 their size by default, which may seem counter-intuitive but makes
1989 it possible to overlay them on modular types easily. */
1993 /* Propagate the reverse storage order flag to the record type so
1994 that the required byte swapping is performed when retrieving the
1995 enclosed modular value. */
2001 /* Don't declare the field as addressable since we won't be taking
2002 its address and this would prevent create_field_decl from making
2003 a bitfield. */
2004 gnu_field
2008 /* We will output additional debug info manually below. */
2011 /* Make the original array type a parallel/debug type. Note that
2012 gnat_get_array_descr_info needs a TYPE_IMPL_PACKED_ARRAY_P type
2013 so we use an intermediate step for standard DWARF. */
2015 {
2020 }
2021 }
2023 /* If the type we are dealing with has got a smaller alignment than the
2024 natural one, we need to wrap it up in a record type and misalign the
2025 latter; we reuse the padding machinery for this purpose. */
2027 {
2030 /* Set the RM size before wrapping the type. */
2033 /* Create a stripped-down declaration, mainly for debugging. */
2035 gnat_entity);
2037 gnu_type
2043 }
2048 /* The type of the Low and High bounds can be our type if this is
2049 a type from Standard, so set them at the end of the function. */
2060 /* See the E_Signed_Integer_Subtype case for the rationale. */
2077 SET_TYPE_RM_MIN_VALUE
2080 debug_info_p));
2082 SET_TYPE_RM_MAX_VALUE
2085 debug_info_p));
2087 /* Inherit our alias set from what we're a subtype of, as for
2088 integer subtypes. */
2091 /* One of the above calls might have caused us to be elaborated,
2092 so don't blow up if so. */
2096 /* Array Types and Subtypes
2098 In GNAT unconstrained array types are represented by E_Array_Type and
2099 constrained array types are represented by E_Array_Subtype. They are
2100 translated into UNCONSTRAINED_ARRAY_TYPE and ARRAY_TYPE respectively.
2101 But there are no actual objects of an unconstrained array type; all we
2102 have are pointers to that type. In addition to the type node itself,
2103 4 other types associated with it are built in the process:
2105 1. the array type (suffix XUA) containing the actual data,
2107 2. the template type (suffix XUB) containing the bounds,
2109 3. the fat pointer type (suffix XUP) representing a pointer or a
2110 reference to the unconstrained array type:
2111 XUP = struct { XUA *, XUB * }
2113 4. the object record type (suffix XUT) containing bounds and data:
2114 XUT = struct { XUB, XUA }
2116 The bounds of the array type XUA (de)reference the XUB * field of a
2117 PLACEHOLDER_EXPR for the fat pointer type XUP, so the array type XUA
2118 is to be interpreted in the context of the fat pointer type XUB for
2119 debug info purposes. */
2122 {
2125 const bool convention_fortran_p
2134 Entity_Id gnat_index;
2138 /* Create the type for the component now, as it simplifies breaking
2139 type reference loops. */
2140 comp_type
2143 {
2144 /* As a side effect, the type may have been translated. */
2147 }
2149 /* We complete an existing dummy fat pointer type in place. This both
2150 avoids further complex adjustments in update_pointer_to and yields
2151 better debugging information in DWARF by leveraging the support for
2152 incomplete declarations of "tagged" types in the DWARF back-end. */
2155 {
2158 gnu_ptr_template =
2162 /* Save the contents of the dummy type for update_pointer_to. */
2168 }
2169 else
2170 {
2174 }
2176 /* Make a node for the array. If we are not defining the array
2177 suppress expanding incomplete types. */
2180 /* The component may refer to this type, so defer completion of any
2181 incomplete types. */
2183 {
2184 defer_incomplete_level++;
2186 }
2188 /* Build the fat pointer type. Use a "void *" object instead of
2189 a pointer to the array type since we don't have the array type
2190 yet (it will reference the fat pointer via the bounds). Note
2191 that we reuse the existing fields of a dummy type because for:
2193 type Arr is array (Positive range <>) of Element_Type;
2194 type Array_Ref is access Arr;
2195 Var : Array_Ref := Null;
2197 in a declarative part, Arr will be frozen only after Var, which
2198 means that the fields used in the CONSTRUCTOR built for Null are
2199 those of the dummy type, which in turn means that COMPONENT_REFs
2200 of Var may be built with these fields. Now if COMPONENT_REFs of
2201 Var are also built later with the fields of the final type, the
2202 aliasing machinery may consider that the accesses are distinct
2203 if the FIELD_DECLs are distinct as objects. */
2205 {
2214 }
2215 else
2216 {
2217 /* We make the fields addressable for the sake of compatibility
2218 with languages for which the regular fields are addressable. */
2219 fld
2229 }
2231 /* If the GNAT encodings are used, give the fat pointer type a name.
2232 If this is a packed type implemented specially, tell the debugger
2233 how to interpret the underlying bits by fetching the name of the
2234 implementation type. But, in any case, mark it as artificial so
2235 the debugger can skip it. */
2236 const Entity_Id gnat_name
2238 ? PAT
2240 tree xup_name
2245 gnat_entity);
2247 /* Build a reference to the template from a PLACEHOLDER_EXPR that
2248 is the fat pointer. This will be used to access the individual
2249 fields once we build them. */
2253 gnu_template_reference
2258 /* Now create the GCC type for each index and add the fields for that
2259 index to the template. */
2265 {
2267 const bool is_flb
2277 /* Update the maximum size of the array in elements. */
2279 gnu_max_size
2282 /* Now build the self-referential bounds of the index type. */
2286 /* Make the FIELD_DECLs for the low and high bounds of this
2287 type and then make extractions of these fields from the
2288 template. */
2291 gnu_index_type,
2294 /* Mark the field specifically for INSTANTIATE_LOAD_IN_EXPR. */
2301 gnu_index_type,
2304 /* Mark the field specifically for INSTANTIATE_LOAD_IN_EXPR. */
2311 /* We can't use build_component_ref here since the template type
2312 isn't complete yet. */
2314 {
2317 NULL_TREE);
2319 }
2323 NULL_TREE);
2329 /* Compute the size of this dimension. See the E_Array_Subtype
2330 case below for the rationale. */
2336 else
2337 gnu_high
2341 gnu_max,
2346 /* Make a range type with the new range in the Ada base type.
2347 Then make an index type with the size range in sizetype. */
2351 gnu_orig_min,
2352 gnu_orig_max),
2353 gnat_entity);
2357 }
2359 /* Install all the fields into the template. */
2364 gnu_template_fields
2367 debug_info_p);
2370 /* If Component_Size is not already specified, annotate it with the
2371 size of the component. */
2376 /* Compute the maximum size of the array in units. */
2378 gnu_max_size
2381 /* Now build the array type. */
2384 {
2395 }
2397 /* If an alignment is specified for an array that is not a packed type
2398 implemented specially, use the alignment if it is valid and, if it
2399 was requested with an explicit clause, preserve the information. */
2401 {
2404 gnat_entity,
2408 }
2410 /* Tag top-level ARRAY_TYPE nodes for packed arrays and their
2411 implementation types as such so that the debug information back-end
2412 can output the appropriate description for them. */
2425 /* Adjust the type of the pointer-to-array field of the fat pointer
2426 and preserve its existing alias set, if any. Note that calling
2427 again record_component_aliases on the fat pointer is not enough
2428 because this may leave dangling references to the existing alias
2429 set from types containing a fat pointer component. If this is
2430 a packed type implemented specially, then use a ref-all pointer
2431 type since the implementation type may vary between constrained
2432 subtypes and unconstrained base type. */
2435 else
2440 /* If the maximum size doesn't overflow, use it. */
2447 /* See the above description for the rationale. */
2448 tree gnu_tmp_decl
2454 /* Create the type to be designated by thin pointers: a record type for
2455 the array and its template. We used to shift the fields to have the
2456 template at a negative offset, but this was somewhat of a kludge; we
2457 now shift thin pointer values explicitly but only those which have a
2458 TYPE_UNCONSTRAINED_ARRAY attached to the designated RECORD_TYPE.
2459 If the GNAT encodings are used, give it a name. */
2460 tree xut_name
2465 debug_info_p);
2470 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2471 corresponding fat pointer. */
2478 /* If this is a packed type implemented specially, then process the
2479 implementation type so it is elaborated in the proper scope. */
2481 {
2482 /* Save the XUA type as our equivalent temporarily for the call
2483 to gnat_to_gnu_type on the OAT below. */
2487 }
2489 /* If this is precisely the implementation type and it has the same
2490 component as the original type (which happens for peculiar index
2491 types), copy the alias set from the latter; this ensures that all
2492 implementation types built on the fly have the same alias set. */
2496 }
2504 /* This is the actual data type for array variables. Multidimensional
2505 arrays are implemented as arrays of arrays. Note that arrays which
2506 have sparse enumeration subtypes as index components create sparse
2507 arrays, which is obviously space inefficient but so much easier to
2508 code for now.
2510 Also note that the subtype never refers to the unconstrained array
2511 type, which is somewhat at variance with Ada semantics.
2513 First check to see if this is simply a renaming of the array type.
2514 If so, the result is the array type. */
2518 ;
2519 else
2520 {
2523 const bool convention_fortran_p
2533 /* First create the GCC type for each index and find out whether
2534 special types are needed for debugging information. */
2537 gnat_base_index
2543 {
2549 tree gnu_base_index_type
2555 /* We try to create subtypes for discriminants used as bounds
2556 that are more restrictive than those declared, by using the
2557 bounds of the index type of the base array type. This will
2558 make it possible to calculate the maximum size of the record
2559 type more conservatively. This may have already been done by
2560 the front-end (Exp_Ch3.Adjust_Discriminants), in which case
2561 there will be a conversion that needs to be removed first. */
2566 {
2570 gnu_base_orig_min,
2571 gnu_base_orig_max);
2572 }
2578 {
2582 gnu_base_orig_min,
2583 gnu_base_orig_max);
2584 }
2586 /* Update the maximum size of the array in elements. Here we
2587 see if any constraint on the index type of the base type
2588 can be used in the case of self-referential bounds on the
2589 index type of the array type. We look for a non-"infinite"
2590 and non-self-referential bound from any type involved and
2591 handle each bound separately. */
2593 {
2596 else
2603 {
2608 }
2616 else
2623 {
2628 }
2634 gnu_max_size
2636 }
2638 /* Convert the bounds to the base type for consistency below. */
2646 /* See if the base array type is already flat. If it is, we
2647 are probably compiling an ACATS test but it will cause the
2648 code below to malfunction if we don't handle it specially. */
2652 {
2656 }
2658 /* Similarly, if one of the values overflows in sizetype and the
2659 range is null, use 1..0 for the sizetype bounds. */
2664 {
2668 }
2670 /* If the minimum and maximum values both overflow in sizetype,
2671 but the difference in the original type does not overflow in
2672 sizetype, ignore the overflow indication. */
2676 && !TREE_OVERFLOW
2679 gnu_index_base_type,
2680 gnu_orig_max,
2681 gnu_orig_min))))
2682 {
2686 }
2688 /* Compute the size of this dimension in the general case. We
2689 need to provide GCC with an upper bound to use but have to
2690 deal with the "superflat" case. There are three ways to do
2691 this. If we can prove that the array can never be superflat,
2692 we can just use the high bound of the index type. */
2695 /* Bit-Packed Array Impl. Types are never superflat. */
2697 && Is_Bit_Packed_Array
2701 /* Otherwise, if the high bound is constant but the low bound is
2702 not, we use the expression (hb >= lb) ? lb : hb + 1 for the
2703 lower bound. Note that the comparison must be done in the
2704 original type to avoid any overflow during the conversion. */
2707 {
2709 gnu_min
2712 boolean_type_node,
2713 gnu_orig_max,
2714 gnu_orig_min),
2715 gnu_min,
2717 size_one_node));
2718 }
2720 /* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
2721 in all the other cases. Note that we use int_const_binop for
2722 the shift by 1 if the bound is constant to avoid any unwanted
2723 overflow. */
2724 else
2725 gnu_high
2728 boolean_type_node,
2729 gnu_orig_max,
2730 gnu_orig_min),
2731 gnu_max,
2734 size_one_node)
2736 size_one_node));
2738 /* Reuse the index type for the range type. Then make an index
2739 type with the size range in sizetype. */
2742 gnat_entity);
2744 /* Record whether the range is known to be null at compile time
2745 to disambiguate it from too large ranges. */
2751 /* We need special types for debugging information to point to
2752 the index types if they have variable bounds, are not integer
2753 types, are biased or are wider than sizetype. These are GNAT
2754 encodings, so we have to include them only when all encodings
2755 are requested. */
2765 }
2767 /* Then flatten: create the array of arrays. For an array type
2768 used to implement a packed array, get the component type from
2769 the original array type since the representation clauses that
2770 can affect it are on the latter. */
2773 {
2778 /* One of the above calls might have caused us to be elaborated,
2779 so don't blow up if so. */
2781 {
2784 }
2785 }
2786 else
2787 {
2789 debug_info_p);
2791 /* One of the above calls might have caused us to be elaborated,
2792 so don't blow up if so. */
2794 {
2797 }
2798 }
2800 /* Compute the maximum size of the array in units. */
2802 gnu_max_size
2805 /* Now build the array type. */
2807 {
2820 /* Clear the TREE_OVERFLOW flag, if any, for null arrays. */
2822 {
2825 }
2827 /* Kludge to clear the TREE_OVERFLOW flag for the sake of LTO
2828 on maximally-sized array types designed by access types. */
2838 {
2841 }
2842 }
2844 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
2848 /* If this is a multi-dimensional array and we are at global level,
2849 we need to make a variable corresponding to the stride of the
2850 inner dimensions. */
2852 {
2853 tree gnu_arr_type;
2858 {
2868 /* ??? For now, store the size as a multiple of the
2869 alignment of the element type in bytes so that we
2870 can see the alignment from the tree. */
2878 /* ??? create_type_decl is not invoked on the inner types so
2879 the MULT_EXPR node built above will never be marked. */
2881 }
2882 }
2884 /* Set the TYPE_PACKED flag on packed array types and also on their
2885 implementation types, so that the DWARF back-end can output the
2886 appropriate description for them. */
2896 /* If the maximum size doesn't overflow, use it. */
2903 /* If we need to write out a record type giving the names of the
2904 bounds for debugging purposes, do it now and make the record
2905 type a parallel type. This is not needed for a packed array
2906 since the bounds are conveyed by the original array type. */
2908 && debug_info_p
2910 {
2913 tree gnu_field;
2919 {
2923 /* Make sure to reference the types themselves, and not just
2924 their names, as the debugger may fall back on them. */
2930 }
2934 }
2936 /* If this is a packed array type, make the original array type a
2937 parallel/debug type. Otherwise, if GNAT encodings are used, do
2938 it for the base array type if it is not artificial to make sure
2939 that it is kept in the debug info. */
2941 {
2943 {
2944 tree gnu_name
2946 gnat_entity);
2949 }
2952 {
2953 tree gnu_base_decl
2960 }
2961 }
2963 /* Set our alias set to that of our base type. This gives all
2964 array subtypes the same alias set. */
2967 /* If this is a packed type implemented specially, then replace our
2968 type with the implementation type. */
2970 {
2971 /* First finish the type we had been making so that we output
2972 debugging information for it. */
2975 {
2976 const int quals
2977 = TYPE_QUAL_VOLATILE
2980 }
2981 /* Make it artificial only if the base type was artificial too.
2982 That's sort of "morally" true and will make it possible for
2983 the debugger to look it up by name in DWARF, which is needed
2984 in order to decode the packed array type. */
2985 tree gnu_tmp_decl
2989 gnat_entity);
2990 /* Save it as our equivalent in case the call below elaborates
2991 this type again. */
2997 /* Set the ___XP suffix for GNAT encodings. */
3007 /* We need to attach the index type to the type we just made so
3008 that the actual bounds can later be put into a template. */
3013 {
3015 {
3016 /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
3017 TYPE_MODULUS for modular types so we make an extra
3018 subtype if necessary. */
3020 gnu_inner
3027 /* Check for other cases of overloading. */
3029 }
3034 SET_TYPE_ACTUAL_BOUNDS
3041 SET_TYPE_ACTUAL_BOUNDS
3047 }
3048 }
3050 /* Otherwise, if an alignment is specified, use it if valid and, if
3051 the alignment was requested with an explicit clause, state so. */
3053 {
3056 gnat_entity,
3060 }
3061 }
3065 /* Create the type for a string literal. */
3066 {
3067 Entity_Id gnat_full_type
3072 tree gnu_string_array_type
3074 tree gnu_string_index_type
3077 tree gnu_lower_bound
3080 tree gnu_length
3082 gnu_string_index_type);
3083 tree gnu_upper_bound
3085 gnu_lower_bound,
3088 integer_one_node)));
3089 tree gnu_index_type
3093 gnu_lower_bound,
3094 gnu_upper_bound),
3095 gnat_entity);
3097 gnu_type
3100 gnu_index_type);
3104 }
3107 /* Record Types and Subtypes
3109 A record type definition is transformed into the equivalent of a C
3110 struct definition. The fields that are the discriminants which are
3111 found in the Full_Type_Declaration node and the elements of the
3112 Component_List found in the Record_Type_Definition node. The
3113 Component_List can be a recursive structure since each Variant of
3114 the Variant_Part of the Component_List has a Component_List.
3116 Processing of a record type definition comprises starting the list of
3117 field declarations here from the discriminants and the calling the
3118 function components_to_record to add the rest of the fields from the
3119 component list and return the gnu type node. The function
3120 components_to_record will call itself recursively as it traverses
3121 the tree. */
3124 {
3128 {
3129 const Node_Id first_component
3131 tree gnu_component_type
3135 }
3137 Node_Id gnat_constr;
3140 tree gnu_get_parent;
3141 /* Set PACKED in keeping with gnat_to_gnu_field. */
3142 const int packed
3150 const bool is_extension
3153 const bool has_rep
3154 = is_extension
3160 /* See if all fields have a rep clause. Stop when we find one
3161 that doesn't. */
3170 {
3173 }
3175 /* If this is a record extension, go a level further to find the
3176 record definition. Also, verify we have a Parent_Subtype. */
3178 {
3185 }
3187 /* Make a node for the record type. */
3194 /* If the record type has discriminants, pointers to it may also point
3195 to constrained subtypes of it, so mark it as may_alias for LTO. */
3197 prepend_one_attribute
3200 gnat_entity);
3204 /* Some component may refer to this type, so defer completion of any
3205 incomplete types. */
3207 {
3208 defer_incomplete_level++;
3210 }
3212 /* If both a size and rep clause were specified, put the size on
3213 the record type now so that it can get the proper layout. */
3218 /* Always set the alignment on the record type here so that it can
3219 get the proper layout. */
3224 else
3225 {
3228 /* If a type needs strict alignment, then its type size will also
3229 be the RM size (see below). Cap the alignment if needed, lest
3230 it may cause this type size to become too large. */
3232 {
3237 }
3239 /* Similarly if an Object_Size clause has been specified. */
3241 {
3246 }
3247 }
3249 /* If we have a Parent_Subtype, make a field for the parent. If
3250 this record has rep clauses, force the position to zero. */
3252 {
3255 tree gnu_parent;
3258 /* A major complexity here is that the parent subtype will
3259 reference our discriminants in its Stored_Constraint list.
3260 But those must reference the parent component of this record
3261 which is precisely of the parent subtype we have not built yet!
3262 To break the circle we first build a dummy COMPONENT_REF which
3263 represents the "get to the parent" operation and initialize
3264 each of those discriminants to a COMPONENT_REF of the above
3265 dummy parent referencing the corresponding discriminant of the
3266 base type of the parent subtype. */
3271 gnu_dummy_parent_type),
3272 NULL_TREE);
3279 {
3280 tree gnu_field
3283 save_gnu_tree
3288 }
3290 /* Then we build the parent subtype. If it has discriminants but
3291 the type itself has unknown discriminants, this means that it
3292 doesn't contain information about how the discriminants are
3293 derived from those of the ancestor type, so it cannot be used
3294 directly. Instead it is built by cloning the parent subtype
3295 of the underlying record view of the type, for which the above
3296 derivation of discriminants has been made explicit. */
3299 {
3302 /* If we are defining the type, the underlying record
3303 view must already have been elaborated at this point.
3304 Otherwise do it now as its parent subtype cannot be
3305 technically elaborated on its own. */
3308 else
3313 /* Substitute the "get to the parent" of the type for that
3314 of its underlying record view in the cloned type. */
3319 {
3321 tree gnu_ref
3324 gnu_parent
3326 }
3327 }
3328 else
3331 /* The parent field needs strict alignment so, if it is to
3332 be created with a component clause below, then we need
3333 to apply the same adjustment as in gnat_to_gnu_field. */
3335 {
3336 /* ??? For historical reasons, we do it on strict-alignment
3337 platforms only, where it is really required. This means
3338 that a confirming representation clause will change the
3339 behavior of the compiler on the other platforms. */
3342 else
3343 parent_packed
3345 }
3347 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
3348 initially built. The discriminants must reference the fields
3349 of the parent subtype and not those of its base type for the
3350 placeholder machinery to properly work. */
3352 {
3353 /* The actual parent subtype is the full view. */
3355 {
3358 else
3360 }
3366 {
3367 Entity_Id field;
3376 }
3377 }
3379 /* The "get to the parent" COMPONENT_REF must be given its
3380 proper type... */
3383 /* ...and reference the _Parent field of this record. */
3384 gnu_field
3387 has_rep
3389 has_rep
3395 }
3397 /* Make the fields for the discriminants and put them into the record
3398 unless it's an Unchecked_Union. */
3403 {
3404 /* If this is a record extension and this discriminant is the
3405 renaming of another discriminant, we've handled it above. */
3410 gnu_field
3412 debug_info_p);
3414 /* Make an expression using a PLACEHOLDER_EXPR from the
3415 FIELD_DECL node just created and link that with the
3416 corresponding GNAT defining identifier. */
3424 {
3427 }
3428 }
3430 /* If we have a derived untagged type that renames discriminants in
3431 the parent type, the (stored) discriminants are just a copy of the
3432 discriminants of the parent type. This means that any constraints
3433 added by the renaming in the derivation are disregarded as far as
3434 the layout of the derived type is concerned. To rescue them, we
3435 change the type of the (stored) discriminants to a subtype with
3436 the bounds of the type of the visible discriminants. */
3438 && !is_extension
3444 /* Ignore access discriminants. */
3447 {
3450 tree gnu_ref
3454 /* GNU_REF must be an expression using a PLACEHOLDER_EXPR built
3455 just above for one of the stored discriminants. */
3463 }
3465 /* If this is a derived type with discriminants and these discriminants
3466 affect the initial shape it has inherited, factor them in. */
3468 && !is_extension
3476 {
3477 tree gnu_parent_type
3486 /* Set the layout of the type to match that of the parent type,
3487 doing required substitutions. Note that, if we do not use the
3488 GNAT encodings, we don't need debug info for the inner record
3489 types, as they will be part of the embedding variant record's
3490 debug info. */
3491 copy_and_substitute_in_layout
3493 gnu_subst_list,
3495 }
3496 else
3497 {
3498 /* Add the fields into the record type and finish it up. */
3505 NULL);
3507 /* Empty classes have the size of a storage unit in C++. */
3510 {
3514 }
3516 /* If the type needs strict alignment, then no object of the type
3517 may have a size smaller than the natural size, which means that
3518 the RM size of the type is equal to the type size. */
3522 /* If there are entities in the chain corresponding to components
3523 that we did not elaborate, ensure we elaborate their types if
3524 they are itypes. */
3533 }
3535 /* Fill in locations of fields. */
3537 }
3541 /* If an equivalent type is present, that is what we should use.
3542 Otherwise, fall through to handle this like a record subtype
3543 since it may have constraints. */
3545 {
3549 }
3551 /* ... fall through ... */
3558 /* Otherwise, first ensure the base type is elaborated. Then, if we are
3559 changing the type, make a new type with each field having the type of
3560 the field in the new subtype but the position computed by transforming
3561 every discriminant reference according to the constraints. We don't
3562 see any difference between private and non-private type here since
3563 derivations from types should have been deferred until the completion
3564 of the private type. */
3565 else
3566 {
3569 /* Some component may refer to this type, so defer completion of any
3570 incomplete types. We also need to do it for the special subtypes
3571 designated by access subtypes in case they are recursive, see the
3572 E_Access_Subtype case below. */
3577 {
3578 defer_incomplete_level++;
3580 }
3582 tree gnu_base_type
3586 {
3589 }
3591 /* When the subtype has discriminants and these discriminants affect
3592 the initial shape it has inherited, factor them in. But for an
3593 Unchecked_Union (it must be an itype), just return the type. */
3598 {
3601 tree gnu_unpad_base_type;
3610 /* Set the size, alignment and alias set of the type to match
3611 those of the base type, doing required substitutions. */
3613 gnu_subst_list);
3617 else
3620 /* Set the layout of the type to match that of the base type,
3621 doing required substitutions. We will output debug info
3622 manually below so pass false as last argument. */
3627 /* Fill in locations of fields. */
3630 /* If debugging information is being written for the type and if
3631 we are asked to output GNAT encodings, write a record that
3632 shows what we are a subtype of and also make a variable that
3633 indicates our size, if still variable. */
3636 {
3638 tree gnu_unpad_base_name
3646 build_reference_type
3648 gnu_subtype_marker,
3664 }
3666 /* Or else, if the subtype is artificial and GNAT encodings are
3667 not used, use the base record type as the debug type. */
3669 && artificial_p
3672 }
3674 /* Otherwise, go down all the components in the new type and make
3675 them equivalent to those in the base type. */
3676 else
3677 {
3687 gnat_to_gnu_field_decl
3690 }
3691 }
3696 /* Use the special descriptor type for dispatch tables if needed,
3697 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3698 Note that we are only required to do so for static tables in
3699 order to be compatible with the C++ ABI, but Ada 2005 allows
3700 to extend library level tagged types at the local level so
3701 we do it in the non-static case as well. */
3704 {
3708 }
3710 /* ... fall through ... */
3717 {
3718 /* The designated type and its equivalent type for gigi. */
3721 /* Whether it comes from a limited with. */
3722 const bool is_from_limited_with
3725 /* Whether it is a completed Taft Amendment type. Such a type is to
3726 be treated as coming from a limited with clause if it is not in
3727 the main unit, i.e. we break potential circularities here in case
3728 the body of an external unit is loaded for inter-unit inlining. */
3729 const bool is_completed_taft_type
3733 /* The "full view" of the designated type. If this is an incomplete
3734 entity from a limited with, treat its non-limited view as the full
3735 view. Otherwise, if this is an incomplete or private type, use the
3736 full view. In the former case, we might point to a private type,
3737 in which case, we need its full view. Also, we want to look at the
3738 actual type used for the representation, so this takes a total of
3739 three steps. */
3740 Entity_Id gnat_desig_full_direct_first
3741 = (is_from_limited_with
3745 Entity_Id gnat_desig_full_direct
3746 = ((is_from_limited_with
3751 Entity_Id gnat_desig_full
3753 /* The type actually used to represent the designated type, either
3754 gnat_desig_full or gnat_desig_equiv. */
3755 Entity_Id gnat_desig_rep;
3756 /* We want to know if we'll be seeing the freeze node for any
3757 incomplete type we may be pointing to. */
3758 const bool in_main_unit
3762 /* True if we make a dummy type here. */
3764 /* The mode to be used for the pointer type. */
3765 scalar_int_mode p_mode;
3766 /* The GCC type used for the designated type. */
3773 /* If either the designated type or its full view is an unconstrained
3774 array subtype, replace it with the type it's a subtype of. This
3775 avoids problems with multiple copies of unconstrained array types.
3776 Likewise, if the designated type is a subtype of an incomplete
3777 record type, use the parent type to avoid order of elaboration
3778 issues. This can lose some code efficiency, but there is no
3779 alternative. */
3790 /* Set the type that's the representation of the designated type. */
3791 gnat_desig_rep
3794 /* If we already know what the full type is, use it. */
3798 /* Get the type of the thing we are to point to and build a pointer to
3799 it. If it is a reference to an incomplete or private type with a
3800 full view that is a record, an array or an access, make a dummy type
3801 and get the actual type later when we have verified it is safe. */
3808 /* Likewise if this is a reference to a record, an array or a
3809 subprogram type and we are to defer elaborating incomplete
3810 types. We do this because this access type may be the full
3811 view of a private type. */
3818 /* If this is a reference from a limited_with type back to our
3819 main unit and there's a freeze node for it, either we have
3820 already processed the declaration and made the dummy type,
3821 in which case we just reuse the latter, or we have not yet,
3822 in which case we make the dummy type and it will be reused
3823 when the declaration is finally processed. In both cases,
3824 the pointer eventually created below will be automatically
3825 adjusted when the freeze node is processed. */
3826 || (in_main_unit
3827 && is_from_limited_with
3829 {
3832 }
3834 /* Otherwise handle the case of a pointer to itself. */
3836 {
3837 gnu_type
3841 }
3843 /* If expansion is disabled, the equivalent type of a concurrent type
3844 is absent, so we use the void pointer type. */
3848 /* If the ultimately designated type is an incomplete type with no full
3849 view, we use the void pointer type in LTO mode to avoid emitting a
3850 dummy type in the GIMPLE IR. We cannot do that in regular mode as
3851 the name of the dummy type in used by GDB for a global lookup. */
3857 /* Finally, handle the default case where we can just elaborate our
3858 designated type. */
3859 else
3862 /* It is possible that a call to gnat_to_gnu_type above resolved our
3863 type. If so, just return it. */
3865 {
3868 }
3870 /* Access-to-unconstrained-array types need a special treatment. */
3872 {
3873 /* If the processing above got something that has a pointer, then
3874 we are done. This could have happened either because the type
3875 was elaborated or because somebody else executed the code. */
3880 }
3882 /* If we haven't done it yet, build the pointer type the usual way. */
3884 {
3885 /* Modify the designated type if we are pointing only to constant
3886 objects, but don't do it for a dummy type. */
3889 gnu_desig_type
3892 gnu_type
3895 }
3897 /* If the designated type is not declared in the main unit and we made
3898 a dummy node for it, save our definition, elaborate the actual type
3899 and replace the dummy type we made with the actual one. But if we
3900 are to defer actually looking up the actual type, make an entry in
3901 the deferred list instead. If this is from a limited with, we may
3902 have to defer until the end of the current unit. */
3904 {
3906 gnu_type
3912 gnat_entity);
3919 && !is_from_limited_with
3921 {
3924 }
3925 else
3926 {
3936 }
3937 }
3938 }
3943 /* If we are just annotating types and have no equivalent record type,
3944 just use the void pointer type. */
3948 /* The run-time representation is the equivalent type. */
3949 else
3950 {
3953 }
3955 /* The designated subtype must be elaborated as well, if it does
3956 not have its own freeze node. */
3971 /* We treat this as identical to its base type; any constraint is
3972 meaningful only to the front-end. */
3976 /* The designated subtype must be elaborated as well, if it does
3977 not have its own freeze node. */
3982 {
3983 tree gnu_design_base_type
3988 /* If we are to defer elaborating incomplete types, make a dummy
3989 type node and elaborate it later. */
3991 {
3994 p->old_type
3999 }
4001 /* Otherwise elaborate the designated subtype only if its base type
4002 has already been elaborated. */
4006 }
4009 /* Subprogram Entities
4011 The following access functions are defined for subprograms:
4013 Etype Return type or Standard_Void_Type.
4014 First_Formal The first formal parameter.
4015 Is_Imported Indicates that the subprogram has appeared in
4016 an INTERFACE or IMPORT pragma. For now we
4017 assume that the external language is C.
4018 Is_Exported Likewise but for an EXPORT pragma.
4019 Is_Inlined True if the subprogram is to be inlined.
4021 Each parameter is first checked by calling must_pass_by_ref on its
4022 type to determine if it is passed by reference. For parameters which
4023 are copied in, if they are Ada In Out or Out parameters, their return
4024 value becomes part of a record which becomes the return type of the
4025 function (C function - note that this applies only to Ada procedures
4026 so there is no Ada return type). Additional code to store back the
4027 parameters will be generated on the caller side. This transformation
4028 is done here, not in the front-end.
4030 The intended result of the transformation can be seen from the
4031 equivalent source rewritings that follow:
4033 struct temp {int a,b};
4034 procedure P (A,B: In Out ...) is temp P (int A,B)
4035 begin {
4036 .. ..
4037 end P; return {A,B};
4038 }
4040 temp t;
4041 P(X,Y); t = P(X,Y);
4042 X = t.a , Y = t.b;
4044 For subprogram types we need to perform mainly the same conversions to
4045 GCC form that are needed for procedures and function declarations. The
4046 only difference is that at the end, we make a type declaration instead
4047 of a function declaration. */
4052 {
4053 tree gnu_ext_name
4055 const enum inline_status_t inline_status
4057 /* Subprograms marked both Intrinsic and Always_Inline need not
4058 have a body of their own. */
4059 const bool extern_flag
4061 || imported_p
4064 tree gnu_param_list;
4066 /* A parameter may refer to this type, so defer completion of any
4067 incomplete types. */
4069 {
4070 defer_incomplete_level++;
4072 }
4074 /* If the subprogram has an alias, it is probably inherited, so
4075 we can use the original one. If the original "subprogram"
4076 is actually an enumeration literal, it may be the first use
4077 of its type, so we must elaborate that type now. */
4079 {
4087 /* Elaborate any itypes in the parameters of this entity. */
4094 /* Materialize renamed subprograms in the debugging information
4095 when the renamed object is known at compile time; we consider
4096 such renamings as imported declarations.
4098 Because the parameters in generic instantiations are generally
4099 materialized as renamings, we often end up having both the
4100 renamed subprogram and the renaming in the same context and with
4101 the same name; in this case, renaming is both useless debug-wise
4102 and potentially harmful as name resolution in the debugger could
4103 return twice the same entity! So avoid this case. */
4105 && !artificial_p
4112 {
4117 }
4120 }
4122 /* Get the GCC tree for the (underlying) subprogram type. If the
4123 entity is an actual subprogram, also get the parameter list. */
4124 gnu_type
4128 {
4133 }
4135 /* Deal with platform-specific calling conventions. */
4137 prepend_one_attribute
4140 gnat_entity);
4142 /* If we should request stack realignment for a foreign convention
4143 subprogram, do so. Note that this applies to task entry points
4144 in particular. */
4146 prepend_one_attribute
4149 gnat_entity);
4151 /* Deal with a pragma Linker_Section on a subprogram. */
4157 /* If we are defining the subprogram and it has an Address clause
4158 we must get the address expression from the saved GCC tree for the
4159 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4160 the address expression here since the front-end has guaranteed
4161 in that case that the elaboration has no effects. If there is
4162 an Address clause and we are not defining the object, just
4163 make it a constant. */
4165 {
4169 gnu_address
4176 /* Convert the type of the object to a reference type that can
4177 alias everything as per RM 13.3(19). */
4178 gnu_type
4183 gnu_decl
4189 }
4191 /* If this is a mere subprogram type, just create the declaration. */
4193 {
4196 gnu_decl
4199 }
4201 /* Otherwise create the subprogram declaration with the external name,
4202 the type and the parameter list. However, if this a reference to
4203 the allocation routines, reuse the canonical declaration nodes as
4204 they come with special properties. */
4205 else
4206 {
4211 else
4212 gnu_decl
4218 gnat_entity);
4219 }
4220 }
4231 {
4232 const bool is_from_limited_with
4234 /* Get the "full view" of this entity. If this is an incomplete
4235 entity from a limited with, treat its non-limited view as the
4236 full view. Otherwise, use either the full view or the underlying
4237 full view, whichever is present. This is used in all the tests
4238 below. */
4239 const Entity_Id full_view
4240 = is_from_limited_with
4248 /* If this is an incomplete type with no full view, it must be a Taft
4249 Amendment type or an incomplete type coming from a limited context,
4250 in which cases we return a dummy type. Otherwise, we just get the
4251 type from its Etype. */
4253 {
4255 {
4258 }
4259 else
4260 {
4261 gnu_decl
4264 }
4265 }
4267 /* Or else, if we already made a type for the full view, reuse it. */
4271 /* Or else, if we are not defining the type or there is no freeze
4272 node on it, get the type for the full view. Likewise if this is
4273 a limited_with'ed type not declared in the main unit, which can
4274 happen for incomplete formal types instantiated on a type coming
4275 from a limited_with clause. */
4278 || (is_from_limited_with
4280 {
4283 }
4285 /* Otherwise, make a dummy type entry which will be replaced later.
4286 Save it as the full declaration's type so we can do any needed
4287 updates when we see it. */
4288 else
4289 {
4295 }
4296 }
4300 /* Class-wide types are always transformed into their root type. */
4309 /* If we are just annotating types and have no equivalent record type,
4310 just return void_type, except for root types that have discriminants
4311 because the discriminants will very likely be used in the declarative
4312 part of the associated body so they need to be translated. */
4314 {
4318 {
4320 Entity_Id gnat_field;
4322 /* This is a minimal version of the E_Record_Type handling. */
4329 {
4330 tree gnu_field
4342 }
4346 }
4347 else
4349 }
4351 /* Concurrent types are always transformed into their record type. */
4352 else
4363 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4364 we've already saved it, so we don't try to. */
4370 /* This is a SPARK annotation that only reaches here when compiling in
4371 ASIS mode. */
4379 }
4381 /* If this is the clone of a subtype, just reuse the cloned subtype; another
4382 approach would be to set the cloned subtype as the DECL_ORIGINAL_TYPE of
4383 the entity, which would generate a DW_TAG_typedef in the debug info, but
4384 at the cost of the duplication of the GCC type and, more annoyingly, of
4385 the need to update the copy if the cloned subtype is not complete yet. */
4387 {
4392 {
4399 }
4400 }
4402 /* If we had a case where we evaluated another type and it might have
4403 defined this one, handle it here. */
4405 {
4408 }
4410 /* If we are processing a type and there is either no DECL for it or
4411 we just made one, do some common processing for the type, such as
4412 handling alignment and possible padding. */
4414 {
4419 /* Process the attributes, if not already done. Note that the type is
4420 already defined so we cannot pass true for IN_PLACE here. */
4423 /* See if a size was specified, by means of either an Object_Size or
4424 a regular Size clause, and validate it if so.
4426 ??? Don't set the size for a String_Literal since it is either
4427 confirming or we don't handle it properly (if the low bound is
4428 non-constant). */
4430 {
4435 gnu_size
4439 /* ??? The test on Has_Size_Clause must be removed when "unknown" is
4440 no longer represented as Uint_0 (i.e. Use_New_Unknown_Rep). */
4443 gnu_size
4447 }
4449 /* If a size was specified, see if we can make a new type of that size
4450 by rearranging the type, for example from a fat to a thin pointer. */
4452 {
4453 gnu_type
4460 }
4462 /* If the alignment has not already been processed and this is not
4463 an unconstrained array type, see if an alignment is specified.
4464 If not, we pick a default alignment for atomic objects. */
4466 ;
4468 {
4472 /* Warn on suspiciously large alignments. This should catch
4473 errors about the (alignment,byte)/(size,bit) discrepancy. */
4475 {
4476 tree size;
4478 /* If a size was specified, take it into account. Otherwise
4479 use the RM size for records or unions as the type size has
4480 already been adjusted to the alignment. */
4486 else
4489 /* Consider an alignment as suspicious if the alignment/size
4490 ratio is greater or equal to the byte/bit ratio. */
4495 gnat_entity);
4496 }
4497 }
4508 /* See if we need to pad the type. If we did and built a new type,
4509 then create a stripped-down declaration for the original type,
4510 mainly for debugging, unless there was already one. */
4512 {
4520 gnat_entity);
4521 }
4523 /* Now set the RM size of the type. We cannot do it before padding
4524 because we need to accept arbitrary RM sizes on integral types. */
4528 /* Back-annotate the alignment of the type if not already set. */
4530 {
4534 /* If the default alignment of "double" or larger scalar types is
4535 specifically capped and this is not an array with an alignment
4536 clause on the component type, return the cap. */
4538 is_capped_double
4541 is_capped_double
4543 else
4548 else
4552 }
4554 /* Likewise for the size, if any. */
4556 {
4559 /* If the size is self-referential, annotate the maximum value
4560 after saturating it, if need be, to avoid a No_Uint value.
4561 But do not do it for cases where Analyze_Object_Declaration
4562 in Sem_Ch3 would build a default subtype for objects. */
4566 {
4567 const unsigned int align
4570 }
4572 /* If we are just annotating types and the type is tagged, the tag
4573 and the parent components are not generated by the front-end so
4574 alignment and sizes must be adjusted. */
4576 {
4578 const Entity_Id gnat_parent
4580 /* The following test for Known_Alignment preserves the old behavior,
4581 but is probably wrong. */
4582 const unsigned int inherited_align
4583 = derived_p
4588 const unsigned int align
4593 /* If there is neither size clause nor representation clause, the
4594 sizes need to be adjusted. */
4599 {
4600 tree offset
4601 = derived_p
4605 offset
4608 }
4613 /* Tagged types are Strict_Alignment so RM_Size = Esize. */
4616 }
4618 /* Otherwise no adjustment is needed. */
4619 else
4621 }
4623 /* Likewise for the RM size, if any. */
4628 /* If we are at global level, GCC applied variable_size to the size but
4629 this has done nothing. So, if it's not constant or self-referential,
4630 call elaborate_expression_1 to make a variable for it rather than
4631 calculating it each time. */
4636 {
4643 /* ??? For now, store the size as a multiple of the alignment in
4644 bytes so that we can see the alignment from the tree. */
4650 /* ??? gnu_type may come from an existing type so the MULT_EXPR node
4651 may not be marked by the call to create_type_decl below. */
4654 /* For a record type, deal with the variant part, if any, and handle
4655 the Ada size as well. */
4657 {
4662 {
4666 /* If the position of the variant part is constant, subtract
4667 it from the size of the type of the parent to get the new
4668 size. This manual CSE reduces the data size. */
4670 {
4678 }
4679 else
4680 {
4686 /* ??? For now, store the size as a multiple of the
4687 alignment in bytes so that we can see the alignment
4688 from the tree. */
4695 /* ??? For now, store the offset as a multiple of the
4696 alignment in bytes so that we can see the alignment
4697 from the tree. */
4701 DECL_OFFSET_ALIGN
4703 }
4707 }
4711 else
4712 ada_size
4716 }
4717 }
4719 /* Similarly, if this is a record type or subtype at global level, call
4720 elaborate_expression_2 on any field position. Skip any fields that
4721 we haven't made trees for to avoid problems with class-wide types. */
4726 {
4729 /* ??? For now, store the offset as a multiple of the alignment
4730 in bytes so that we can see the alignment from the tree. */
4733 {
4740 /* ??? The context of gnu_field is not necessarily gnu_type
4741 so the MULT_EXPR node built above may not be marked by
4742 the call to create_type_decl below. */
4744 }
4745 }
4747 /* Now check if the type allows atomic access. */
4751 /* If this is not an unconstrained array type, set some flags. */
4753 {
4756 /* Record the property that objects of tagged types are guaranteed to
4757 be properly aligned. This is necessary because conversions to the
4758 class-wide type are translated into conversions to the root type,
4759 which can be less aligned than some of its derived types. */
4764 /* Record whether the type is passed by reference. */
4768 /* Record whether an alignment clause was specified. At this point
4769 scalar types with a non-confirming clause have been wrapped into
4770 a record type, so only scalar types with a confirming clause are
4771 left untouched; we do not set the flag on them except if they are
4772 types whose default alignment is specifically capped in order not
4773 to lose the specified alignment. */
4784 /* Record whether a pragma Universal_Aliasing was specified. Also
4785 consider that it is always present on interface types because,
4786 while they are abstract tagged types and thus no object of these
4787 types exists anywhere, they are used to access objects of types
4788 that implement them. */
4791 {
4792 /* Set TYPE_TYPELESS_STORAGE if this is an aggregate type and
4793 TYPE_UNIVERSAL_ALIASING_P otherwise, since the former is not
4794 available in the latter case Both will effectively put alias
4795 set 0 on the type, but the former is more robust because it
4796 will be streamed in LTO mode. */
4799 else
4801 }
4803 /* If it is passed by reference, force BLKmode to ensure that
4804 objects of this type will always be put in memory. */
4807 }
4809 /* If this is a derived type, relate its alias set to that of its parent
4810 to avoid troubles when a call to an inherited primitive is inlined in
4811 a context where a derived object is accessed. The inlined code works
4812 on the parent view so the resulting code may access the same object
4813 using both the parent and the derived alias sets, which thus have to
4814 conflict. As the same issue arises with component references, the
4815 parent alias set also has to conflict with composite types enclosing
4816 derived components. For instance, if we have:
4818 type D is new T;
4819 type R is record
4820 Component : D;
4821 end record;
4823 we want T to conflict with both D and R, in addition to R being a
4824 superset of D by record/component construction.
4826 One way to achieve this is to perform an alias set copy from the
4827 parent to the derived type. This is not quite appropriate, though,
4828 as we don't want separate derived types to conflict with each other:
4830 type I1 is new Integer;
4831 type I2 is new Integer;
4833 We want I1 and I2 to both conflict with Integer but we do not want
4834 I1 to conflict with I2, and an alias set copy on derivation would
4835 have that effect.
4837 The option chosen is to make the alias set of the derived type a
4838 superset of that of its parent type. It trivially fulfills the
4839 simple requirement for the Integer derivation example above, and
4840 the component case as well by superset transitivity:
4842 superset superset
4843 R ----------> D ----------> T
4845 However, for composite types, conversions between derived types are
4846 translated into VIEW_CONVERT_EXPRs so a sequence like:
4848 type Comp1 is new Comp;
4849 type Comp2 is new Comp;
4850 procedure Proc (C : Comp1);
4852 C : Comp2;
4853 Proc (Comp1 (C));
4855 is translated into:
4857 C : Comp2;
4858 Proc ((Comp1 &) &VIEW_CONVERT_EXPR <Comp1> (C));
4860 and gimplified into:
4862 C : Comp2;
4863 Comp1 *C.0;
4864 C.0 = (Comp1 *) &C;
4865 Proc (C.0);
4867 i.e. generates code involving type punning. Therefore, Comp1 needs
4868 to conflict with Comp2 and an alias set copy is required.
4870 The language rules ensure the parent type is already frozen here. */
4874 {
4876 /* For constrained packed array subtypes, the implementation type is
4877 used instead of the nominal type. */
4885 }
4887 /* Finally get to the appropriate variant, except for the implementation
4888 type of a packed array because the GNU type might be further adjusted
4889 when the original array type is itself processed. */
4892 {
4893 const int quals
4894 = TYPE_QUAL_VOLATILE
4896 /* This is required by free_lang_data_in_type to disable the ODR. */
4901 }
4903 /* If we already made a decl, just set the type, otherwise create it. */
4905 {
4908 }
4909 else
4912 }
4914 /* If we haven't already, associate the ..._DECL node that we just made with
4915 the input GNAT entity node. */
4919 /* Now we are sure gnat_entity has a corresponding ..._DECL node,
4920 eliminate as many deferred computations as possible. */
4923 /* If this is an enumeration or floating-point type, we were not able to set
4924 the bounds since they refer to the type. These are always static. */
4927 {
4931 /* If this is a padded type, we need to use the underlying type. */
4935 /* If this is a floating point type and we haven't set a floating
4936 point type yet, use this in the evaluation of the bounds. */
4944 {
4945 /* Enumeration types have specific RM bounds. */
4948 }
4949 else
4950 {
4951 /* Floating-point types don't have specific RM bounds. */
4954 }
4955 }
4957 /* If we deferred processing of incomplete types, re-enable it. If there
4958 were no other disables and we have deferred types to process, do so. */
4962 {
4965 /* We are back to level 0 for the deferring of incomplete types.
4966 But processing these incomplete types below may itself require
4967 deferring, so preserve what we have and restart from scratch. */
4972 {
4979 }
4980 }
4982 /* If we are not defining this type, see if it's on one of the lists of
4983 incomplete types. If so, handle the list entry now. */
4985 {
4990 {
4994 }
5000 {
5006 }
5007 }
5010 force_global--;
5012 /* If this is a packed array type whose original array type is itself
5013 an itype without freeze node, make sure the latter is processed. */
5021 }
5023 /* Similar, but if the returned value is a COMPONENT_REF, return the
5024 FIELD_DECL. */
5026 tree
5028 {
5035 }
5037 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5038 the GCC type corresponding to that entity. */
5040 tree
5042 {
5043 tree gnu_decl;
5045 /* The back end never attempts to annotate generic types. */
5053 }
5055 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5056 the unpadded version of the GCC type corresponding to that entity. */
5058 tree
5060 {
5067 }
5069 /* Return whether the E_Subprogram_Type/E_Function/E_Procedure GNAT_ENTITY is
5070 a C++ imported method or equivalent.
5072 We use the predicate to find out whether we need to use METHOD_TYPE instead
5073 of FUNCTION_TYPE for GNAT_ENTITY for the sake compatibility with C++. This
5074 in turn determines whether the "thiscall" calling convention is used by the
5075 back-end for GNAT_ENTITY on 32-bit x86/Windows. */
5077 static bool
5079 {
5080 /* A constructor is a method on the C++ side. We deal with it now because
5081 it is declared without the 'this' parameter in the sources and, although
5082 the front-end will create a version with the 'this' parameter for code
5083 generation purposes, we want to return true for both versions. */
5087 /* Check that the subprogram has C++ convention. */
5091 /* And that the type of the first parameter (indirectly) has it too, but
5092 we make an exception for Interfaces because they need not be imported. */
5102 /* This is the main case: a C++ virtual method imported as a primitive
5103 operation of a tagged type. */
5107 /* This is set on the E_Subprogram_Type built for a dispatching call. */
5111 /* A thunk needs to be handled like its associated primitive operation. */
5115 /* Now on to the annoying case: a C++ non-virtual method, imported either
5116 as a non-primitive operation of a tagged type or as a primitive operation
5117 of an untagged type. We cannot reliably differentiate these cases from
5118 their static member or regular function equivalents in Ada, so we ask
5119 the C++ side through the mangled name of the function, as the implicit
5120 'this' parameter is not encoded in the mangled name of a method. */
5122 {
5130 DMGL_GNU_V3
5131 | DMGL_TYPES
5132 | DMGL_PARAMS
5138 /* We need to release MEM once we have a successful demangling. */
5145 {
5146 /* Make sure there is at least one parameter in C++ too. */
5148 {
5151 n_ada_args++;
5157 n_cpp_args++;
5163 }
5164 else
5166 }
5171 }
5174 }
5176 /* Return the inlining status of the GNAT subprogram SUBPROG. */
5178 static enum inline_status_t
5180 {
5188 {
5189 tree gnu_type;
5191 /* This is a kludge to work around a pass ordering issue: for small
5192 record types with many components, i.e. typically bitfields, the
5193 initialization routine can contain many assignments that will be
5194 merged by the GIMPLE store merging pass. But this pass runs very
5195 late in the pipeline, in particular after the inlining decisions
5196 are made, so the inlining heuristics cannot take its outcome into
5197 account. Therefore, we optimistically override the heuristics for
5198 the initialization routine in this case. */
5200 && flag_store_merging
5208 /* If this is an expression function and we're not optimizing for size,
5209 override the heuristics, unless -gnatd.8 is specified. */
5211 && !optimize_size
5216 }
5219 }
5221 /* Finalize the processing of From_Limited_With incomplete types. */
5223 void
5225 {
5232 {
5236 {
5241 }
5244 }
5245 }
5247 /* Return the cloned subtype to be used for GNAT_ENTITY, if the latter is a
5248 kind of subtype that needs to be considered as a clone by Gigi, otherwise
5249 return Empty. */
5251 static Entity_Id
5253 {
5254 Node_Id gnat_decl;
5257 {
5262 /* ... fall through ... */
5265 /* If Cloned_Subtype is Present, this means that this record subtype has
5266 the same layout as that of the specified (sub)type, and also that the
5267 front-end guarantees that the component list is shared. */
5281 /* We return true for the subtypes generated for the actuals of formal
5282 private types in instantiations, so that these actuals are the types
5283 of the instantiated objects in the debug info. */
5291 /* Likewise for the full view of such subtypes when they are private. */
5293 {
5302 }
5307 }
5310 }
5312 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a kind
5313 of type (such E_Task_Type) that has a different type which Gigi uses
5314 for its representation. If the type does not have a special type for
5315 its representation, return GNAT_ENTITY. */
5317 Entity_Id
5319 {
5326 {
5361 }
5364 }
5366 /* Return a GCC tree for a type corresponding to the component type of the
5367 array type or subtype GNAT_ARRAY. DEFINITION is true if this component
5368 is for an array being defined. DEBUG_INFO_P is true if we need to write
5369 debug information for other types that we may create in the process. */
5371 static tree
5374 {
5378 tree gnu_comp_size;
5382 /* If an alignment is specified, use it as a cap on the component type
5383 so that it can be honored for the whole type, but ignore it for the
5384 original type of packed array types. */
5388 else
5391 /* Try to get a packable form of the component if needed. */
5393 && !is_bit_packed
5399 {
5402 }
5403 else
5406 /* Get and validate any specified Component_Size. */
5407 gnu_comp_size
5412 /* If the component type is a RECORD_TYPE that has a self-referential size,
5413 then use the maximum size for the component size. */
5419 /* If the array has aliased components and the component size is zero, force
5420 the unit size to ensure that the components have distinct addresses. */
5426 /* Honor the component size. This is not needed for bit-packed arrays. */
5428 {
5435 else
5438 /* We need to make sure that the size is a multiple of the alignment.
5439 But we do not misalign the component type because of the alignment
5440 of the array type here; this either must have been done earlier in
5441 the packed case or should be rejected in the non-packed case. */
5443 {
5448 }
5449 else
5455 /* If a padding record was made, declare it now since it will never be
5456 declared otherwise. This is necessary to ensure that its subtrees
5457 are properly marked. */
5460 gnat_array);
5461 }
5463 /* This is a very special case where the array has aliased components and the
5464 component size might be zero at run time. As explained above, we force at
5465 least the unit size but we don't want to build a distinct padding type for
5466 each invocation (they are not canonicalized if they have variable size) so
5467 we cache this special padding type as TYPE_PADDING_FOR_COMPONENT. */
5471 {
5474 else
5475 {
5476 gnu_comp_size
5483 gnat_array);
5484 }
5485 }
5487 /* Now check if the type of the component allows atomic access. */
5491 /* If the component type is a padded type made for a non-bit-packed array
5492 of scalars with reverse storage order, we need to propagate the reverse
5493 storage order to the padding type since it is the innermost enclosing
5494 aggregate type around the scalar. */
5496 && !is_bit_packed
5502 {
5503 const int quals
5504 = TYPE_QUAL_VOLATILE
5507 }
5510 }
5512 /* Return whether TYPE requires that formal parameters of TYPE be initialized
5513 when they are Out parameters passed by copy.
5515 This just implements the set of conditions listed in RM 6.4.1(12). */
5517 static bool
5519 {
5536 {
5544 }
5547 }
5549 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM, to be placed
5550 in the parameter list of GNAT_SUBPROG. GNU_PARAM_TYPE is the GCC tree for
5551 the type of the parameter. FIRST is true if this is the first parameter in
5552 the list of GNAT_SUBPROG. Also set CICO to true if the parameter must use
5553 the copy-in copy-out implementation mechanism.
5555 The returned tree is a PARM_DECL, except for the cases where no parameter
5556 needs to be actually passed to the subprogram; the type of this "shadow"
5557 parameter is then returned instead. */
5559 static tree
5562 {
5567 /* The parameter can be indirectly modified if its address is taken. */
5574 tree gnu_param;
5576 /* Make sure to use the proper SLOC for vector ABI warnings. */
5580 /* Builtins are expanded inline and there is no real call sequence involved.
5581 So the type expected by the underlying expander is always the type of the
5582 argument "as is". */
5587 /* Handle the first parameter of a valued procedure specially: it's a copy
5588 mechanism for which the parameter is never allocated. */
5590 {
5594 }
5596 /* Or else, see if a Mechanism was supplied that forced this parameter
5597 to be passed one way or another. */
5599 forced_by_ref
5601 && !foreign
5605 /* Positive mechanism means by copy for sufficiently small parameters. */
5607 {
5612 else
5614 }
5616 /* Otherwise, it's an unsupported mechanism so error out. */
5617 else
5618 {
5621 }
5623 /* Either for foreign conventions, or if the underlying type is not passed
5624 by reference and is as large and aligned as the original type, strip off
5625 a possible padding type. */
5627 {
5638 }
5640 /* For foreign conventions, pass arrays as pointers to the element type.
5641 First check for unconstrained array and get the underlying array. */
5643 gnu_param_type
5646 /* Arrays are passed as pointers to element type for foreign conventions. */
5648 {
5649 /* Strip off any multi-dimensional entries, then strip
5650 off the last array to get the component type. */
5658 }
5660 /* Fat pointers are passed as thin pointers for foreign conventions. */
5662 gnu_param_type
5665 /* Use a pointer type for the "this" pointer of C++ constructors. */
5667 {
5671 }
5673 /* If we were requested or must pass by reference, do so.
5674 If we were requested to pass by copy, do so.
5675 Otherwise, for foreign conventions, pass In Out or Out parameters
5676 or aggregates by reference. For COBOL and Fortran, pass all
5677 integer and FP types that way too. For Convention Ada, use
5678 the standard Ada default. */
5682 && ((foreign
5684 || (foreign
5689 || (!foreign
5691 {
5692 /* We take advantage of 6.2(12) by considering that references built for
5693 parameters whose type isn't by-ref and for which the mechanism hasn't
5694 been forced to by-ref allow only a restricted form of aliasing. */
5695 restricted_aliasing_p
5699 }
5701 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
5707 /* Warn if we are asked to pass by copy but cannot. */
5711 /* If this is an Out parameter that isn't passed by reference and whose
5712 type doesn't require the initialization of formals, we don't make a
5713 PARM_DECL for it. Instead, it will be a VAR_DECL created when we
5714 process the procedure, so just return its type here. Likewise for
5715 the _Init parameter of an initialization procedure or the special
5716 parameter of a valued procedure, never pass them in. */
5718 && !by_ref
5719 && !by_component_ptr
5723 {
5726 }
5740 /* If no Mechanism was specified, indicate what we will use. */
5744 /* Back-annotate the mechanism in all cases. */
5748 }
5750 /* Associate GNAT_SUBPROG with GNU_TYPE, which must be a dummy type, so that
5751 GNAT_SUBPROG is updated when GNU_TYPE is completed.
5753 Ada 2012 (AI05-019) says that freezing a subprogram does not always freeze
5754 the corresponding profile, which means that, by the time the freeze node
5755 of the subprogram is encountered, types involved in its profile may still
5756 be not yet frozen. That's why we need to update GNAT_SUBPROG when we see
5757 the freeze node of types involved in its profile, either types of formal
5758 parameters or the return type. */
5760 static void
5762 {
5770 {
5775 }
5777 /* Even if there is already a slot for GNU_TYPE, we need to set the flag
5778 because the vector might have been just emptied by update_profiles_with.
5779 This can happen when there are 2 freeze nodes associated with different
5780 views of the same type; the type will be really complete only after the
5781 second freeze node is encountered. */
5786 /* Make sure GNAT_SUBPROG is not associated twice with the same dummy type,
5787 since this would mean updating twice its profile. */
5789 {
5793 /* Entity_Id is a simple integer so we can implement a stable order on
5794 the vector with an ordered insertion scheme and binary search. */
5796 {
5803 else
5805 }
5807 /* l == u and therefore is the insertion point. */
5809 }
5810 else
5814 }
5816 /* Update the GCC tree previously built for the profile of GNAT_SUBPROG. */
5818 static void
5820 {
5821 tree gnu_param_list;
5826 {
5827 /* Builtins cannot have their address taken so we can reset them. */
5832 }
5838 /* If GNAT_SUBPROG is an actual subprogram, GNU_SUBPROG is a FUNCTION_DECL
5839 and needs to be adjusted too. */
5841 {
5843 tree gnu_ext_name
5848 }
5849 }
5851 /* Update the GCC trees previously built for the profiles involving GNU_TYPE,
5852 a dummy type which appears in profiles. */
5854 void
5856 {
5864 /* The flag needs to be reset before calling update_profile, in case
5865 associate_subprog_with_dummy_type is again invoked on GNU_TYPE. */
5874 }
5876 /* Return the GCC tree for GNAT_TYPE present in the profile of a subprogram.
5878 Ada 2012 (AI05-0151) says that incomplete types coming from a limited
5879 context may now appear as parameter and result types. As a consequence,
5880 we may need to defer their translation until after a freeze node is seen
5881 or to the end of the current unit. We also aim at handling temporarily
5882 incomplete types created by the usual delayed elaboration scheme. */
5884 static tree
5886 {
5887 /* This is the same logic as the E_Access_Type case of gnat_to_gnu_entity
5888 so the rationale is exposed in that place. These processings probably
5889 ought to be merged at some point. */
5891 const bool is_from_limited_with
5894 Entity_Id gnat_full_direct_first
5895 = (is_from_limited_with
5899 Entity_Id gnat_full_direct
5900 = ((is_from_limited_with
5908 tree gnu_type;
5914 && ((!in_main_unit
5921 {
5925 {
5932 }
5933 }
5938 else
5941 /* Access-to-unconstrained-array types need a special treatment. */
5943 {
5946 }
5949 }
5951 /* Return true if TYPE contains only integral data, recursively if need be. */
5953 static bool
5955 {
5957 {
5972 }
5975 }
5977 /* Return a GCC tree for a subprogram type corresponding to GNAT_SUBPROG.
5978 DEFINITION is true if this is for a subprogram being defined. DEBUG_INFO_P
5979 is true if we need to write debug information for other types that we may
5980 create in the process. Also set PARAM_LIST to the list of parameters.
5981 If GNAT_SUBPROG is bound to a GCC builtin, return the DECL for the builtin
5982 directly instead of its type. */
5984 static tree
5987 {
5994 tree gnu_return_type;
5997 /* Non-null for subprograms containing parameters passed by copy-in copy-out
5998 (In Out or Out parameters not passed by reference), in which case it is
5999 the list of nodes used to specify the values of the In Out/Out parameters
6000 that are returned as a record upon procedure return. The TREE_PURPOSE of
6001 an element of this list is a FIELD_DECL of the record and the TREE_VALUE
6002 is the PARM_DECL corresponding to that field. This list will be saved in
6003 the TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
6008 /* Although the semantics of "pure" units in Ada essentially match those of
6009 "const" in GNU C, the semantics of the Is_Pure flag in GNAT do not say
6010 anything about access to global memory, that's why it needs to be mapped
6011 to "pure" instead of "const" in GNU C. The property is orthogonal to the
6012 "nothrow" property only if the EH circuitry is explicit in the internal
6013 representation of the middle-end: if we are to completely hide the EH
6014 circuitry from it, we need to declare that calls to pure Ada subprograms
6015 that can throw have side effects, since they can trigger an "abnormal"
6016 transfer of control; therefore they cannot be "pure" in the GCC sense. */
6022 /* Look into the return type and get its associated GCC tree if it is not
6023 void, and then compute various flags for the subprogram type. But make
6024 sure not to do this processing multiple times. */
6031 {
6035 }
6037 else
6038 {
6039 /* For foreign convention/intrinsic subprograms, return System.Address
6040 as void * or equivalent; this comprises GCC builtins. */
6045 else
6048 /* If this function returns by reference or on the secondary stack, make
6049 the actual return type the reference type and make a note of that. */
6053 {
6056 }
6058 /* If the Mechanism is By_Reference, ensure this function uses the
6059 target's by-invisible-reference mechanism, which may not be the
6060 same as above (e.g. it might be passing an extra parameter). */
6064 /* Likewise, if the return type is itself By_Reference. */
6068 /* If the type is a padded type and the underlying type would not be
6069 passed by reference or the function has a foreign convention, return
6070 the underlying type. */
6072 && (!default_pass_by_ref
6077 /* If the return type is unconstrained, it must have a maximum size.
6078 Use the padded type as the effective return type. And ensure the
6079 function uses the target's by-invisible-reference mechanism to
6080 avoid copying too much data when it returns. */
6082 {
6086 /* If the size overflows to 0, set it to an arbitrary positive
6087 value so that assignments in the type are preserved. Their
6088 actual size is independent of this positive value. */
6092 {
6095 }
6101 /* Declare it now since it will never be declared otherwise. This
6102 is necessary to ensure that its subtrees are properly marked. */
6109 }
6111 /* If the return type has a size that overflows, we usually cannot have
6112 a function that returns that type. This usage doesn't really make
6113 sense anyway, so issue an error here. */
6118 {
6123 }
6125 /* If the return type is incomplete, there are 2 cases: if the function
6126 returns by reference, then the return type is only linked indirectly
6127 in the profile, so the profile can be seen as complete since it need
6128 not be further modified, only the reference types need be adjusted;
6129 otherwise the profile is incomplete and need be adjusted too. */
6131 {
6134 }
6135 }
6137 /* A procedure (something that doesn't return anything) shouldn't be
6138 considered pure since there would be no reason for calling such a
6139 subprogram. Note that procedures with Out (or In Out) parameters
6140 have already been converted into a function with a return type.
6141 Similarly, if the function returns an unconstrained type, then the
6142 function will allocate the return value on the secondary stack and
6143 thus calls to it cannot be CSE'ed, lest the stack be reclaimed. */
6147 /* Loop over the parameters and get their associated GCC tree. While doing
6148 this, build a copy-in copy-out structure if we need one. */
6149 Entity_Id gnat_param;
6154 {
6155 const bool mech_is_by_ref
6162 /* For a variadic C function, do not build unnamed parameters. */
6167 /* Fetch an existing parameter with complete type and reuse it. But we
6168 didn't save the CICO property so we can only do it for In parameters
6169 or parameters passed by reference. */
6174 {
6177 }
6179 /* Otherwise translate the parameter type and act accordingly. */
6180 else
6181 {
6184 /* For foreign convention/intrinsic subprograms, pass System.Address
6185 as void * or equivalent; this comprises GCC builtins. */
6190 else
6193 /* If the parameter type is incomplete, there are 2 cases: if it is
6194 passed by reference, then the type is only linked indirectly in
6195 the profile, so the profile can be seen as complete since it need
6196 not be further modified, only the reference type need be adjusted;
6197 otherwise the profile is incomplete and need be adjusted too. */
6199 {
6200 Node_Id gnat_decl;
6204 && TYPE_IS_FAT_POINTER_P
6207 {
6209 gnu_param
6219 }
6221 /* ??? This is a kludge to support null procedures in spec taking
6222 a parameter with an untagged incomplete type coming from a
6223 limited context. The front-end creates a body without knowing
6224 anything about the non-limited view, which is illegal Ada and
6225 cannot be supported. Create a parameter with a fake type. */
6233 else
6234 {
6235 /* Build a minimal PARM_DECL without DECL_ARG_TYPE so that
6236 Call_to_gnu will stop if it encounters the PARM_DECL. */
6237 gnu_param
6239 gnu_param_type);
6241 gnu_param_type);
6243 }
6244 }
6246 /* Otherwise build the parameter declaration normally. */
6247 else
6248 {
6249 gnu_param
6253 /* We are returned either a PARM_DECL or a type if no parameter
6254 needs to be passed; in either case, adjust the type. */
6257 else
6258 {
6261 }
6262 }
6263 }
6265 /* If we have a GCC tree for the parameter, register it. */
6268 {
6269 gnu_param_type_list
6275 /* A pure function in the Ada sense which takes an access parameter
6276 may modify memory through it and thus cannot be considered pure
6277 in the GCC sense, unless it's access-to-function. Likewise it if
6278 takes a by-ref In Out or Out parameter. But if it takes a by-ref
6279 In parameter, then it may only read memory through it and can be
6280 considered pure in the GCC sense. */
6286 }
6288 /* If the parameter uses the copy-in copy-out mechanism, allocate a field
6289 for it in the return type and register the association. */
6291 {
6293 {
6296 /* If this is a function, we also need a field for the
6297 return value to be placed. */
6299 {
6300 tree gnu_field
6302 gnu_return_type,
6308 gnu_cico_list
6312 }
6315 /* Set a default alignment to speed up accesses. But we should
6316 not increase the size of the structure too much, lest it does
6317 not fit in return registers anymore. */
6320 }
6322 tree gnu_field
6333 }
6334 }
6336 /* If the subprogram uses the copy-in copy-out mechanism, possibly adjust
6337 and finish up the return type. */
6339 {
6340 /* If we have a CICO list but it has only one entry, we convert
6341 this function into a function that returns this object. */
6345 /* Do not finalize the return type if the subprogram is stubbed
6346 since structures are incomplete for the back-end. */
6348 {
6353 /* Try to promote the mode if the return type is fully returned
6354 in integer registers, again to speed up accesses. */
6356 && gnu_cico_only_integral_type
6358 NULL_TREE))
6359 {
6360 unsigned int size
6363 scalar_int_mode mode;
6368 {
6376 }
6377 }
6379 /* But demote the mode if the return type is partly returned in FP
6380 registers to avoid creating problematic paradoxical subregs.
6381 Note that we need to cater to historical 32-bit architectures
6382 that incorrectly use the mode to select the return mechanism. */
6384 && !gnu_cico_only_integral_type
6387 NULL_TREE))
6393 /* Declare it now since it will never be declared otherwise. This
6394 is necessary to ensure that its subtrees are properly marked. */
6396 gnu_cico_return_type,
6398 }
6401 }
6403 /* The lists have been built in reverse. */
6410 /* Turn imported C++ constructors into their callable form as done in the
6411 front-end, i.e. add the "this" pointer and void the return type. */
6415 {
6416 tree gnu_param_type
6419 tree gnu_param
6421 gnu_param_type);
6422 gnu_param_type_list
6427 }
6429 /* If the profile is incomplete, we only set the (temporary) return and
6430 parameter types; otherwise, we build the full type. In either case,
6431 we reuse an already existing GCC tree that we built previously here. */
6433 {
6435 ;
6436 else
6442 }
6443 else
6444 {
6446 {
6450 {
6454 }
6460 }
6461 else
6462 {
6464 {
6466 gnu_type
6469 }
6470 else
6471 gnu_type
6474 /* GNU_TYPE may be shared since GCC hashes types. Unshare it if it
6475 has a different TYPE_CI_CO_LIST or flags. */
6477 return_by_direct_ref_p,
6478 return_by_invisi_ref_p))
6479 {
6484 }
6485 }
6493 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
6494 corresponding DECL node and check the parameter association. */
6497 {
6501 /* If we have a builtin DECL for that function, use it. Check if
6502 the profiles are compatible and warn if they are not. Note that
6503 the checker is expected to post diagnostics in this case. */
6505 {
6507 {
6508 const enum built_in_function fncode
6512 {
6541 /* This is a generic builtin overloaded on its return
6542 type, so do type resolution based on it. */
6545 gnu_builtin_decl
6547 else
6548 {
6549 post_error
6551 gnat_subprog);
6552 post_error
6554 gnat_subprog);
6556 }
6561 /* This is a generic builtin overloaded on its second
6562 parameter type, so do type resolution based on it. */
6564 && type_for_atomic_builtin_p
6566 gnu_builtin_decl
6567 = resolve_atomic_builtin
6569 else
6570 {
6571 post_error
6573 gnat_subprog);
6574 post_error
6576 gnat_subprog);
6578 }
6582 /* This is a generic builtin overloaded on its third
6583 parameter type, so do type resolution based on it. */
6585 && type_for_atomic_builtin_p
6587 gnu_builtin_decl
6588 = resolve_atomic_builtin
6590 else
6591 {
6592 post_error
6594 gnat_subprog);
6595 post_error
6597 gnat_subprog);
6599 }
6603 post_error
6605 gnat_subprog);
6611 }
6612 }
6615 {
6616 const intrin_binding_t inb
6620 post_error
6622 gnat_subprog);
6625 }
6626 }
6628 /* Inability to find the builtin DECL most often indicates a genuine
6629 mistake, but imports of unregistered intrinsics are sometimes used
6630 on purpose to allow hooking in alternate bodies; we post a warning
6631 conditioned on Wshadow in this case, to let developers be notified
6632 on demand without risking false positives with common default sets
6633 of options. */
6636 }
6638 /* Finally deal with the return mechanism for a function. */
6640 {
6641 /* We return by reference either if this is required by the semantics
6642 of the language or if this is the default for the function. */
6644 || return_by_invisi_ref_p
6648 /* Warn if we are asked to return by copy but cannot. */
6652 /* If no mechanism was specified, indicate what we will use. */
6656 /* Back-annotate the mechanism in all cases. */
6658 }
6659 }
6664 }
6666 /* Return the external name for GNAT_SUBPROG given its entity name. */
6668 static tree
6670 {
6673 /* If there was no specified Interface_Name and the external and
6674 internal names of the subprogram are the same, only use the
6675 internal name to allow disambiguation of nested subprograms. */
6680 }
6682 /* Set TYPE_NONALIASED_COMPONENT on an array type built by means of
6683 build_nonshared_array_type. */
6685 static void
6687 {
6691 }
6693 /* Set TYPE_REVERSE_STORAGE_ORDER on an array type built by means of
6694 build_nonshared_array_type. */
6696 static void
6698 {
6702 }
6704 /* Set TYPE_TYPELESS_STORAGE on an aggregate type. */
6706 static void
6708 {
6712 }
6714 /* Set TYPE_UNIVERSAL_ALIASING_P on a type. */
6716 static void
6718 {
6722 }
6724 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
6726 static bool
6728 {
6735 return
6737 }
6739 /* Return true if the array type GNU_TYPE, which represents a dimension of
6740 GNAT_TYPE, has a non-aliased component in the back-end sense. */
6742 static bool
6744 {
6745 /* If the array type has an aliased component in the front-end sense,
6746 then it also has an aliased component in the back-end sense. */
6750 /* If this is a derived type, then it has a non-aliased component if
6751 and only if its parent type also has one. */
6753 {
6756 gnu_parent_type
6759 }
6761 /* For a multi-dimensional array type, find the component type. */
6766 /* Consider that an array of pointers has an aliased component, which is
6767 sort of logical and helps with Taft Amendment types in LTO mode. */
6771 /* Otherwise, rely exclusively on properties of the element type. */
6773 }
6775 /* Return true if GNAT_ADDRESS is a value known at compile-time. */
6777 static bool
6779 {
6780 /* Handle reference to a constant. */
6783 {
6787 }
6789 /* Catch System'To_Address. */
6794 }
6796 /* Return true if GNAT_INDIC, a N_Subtype_Indication node for the index of a
6797 FLB, cannot yield superflat objects, i.e. if the inequality HB >= LB - 1
6798 is true for these objects. LB and HB are the low and high bounds. */
6800 static bool
6802 {
6808 /* This is a FLB so LB is fixed. */
6812 {
6815 }
6816 else
6819 /* The low bound of the type is a lower bound for HB. */
6823 {
6826 }
6827 else
6830 /* We need at least a signed 64-bit type to catch most cases. */
6836 /* If the low bound is the smallest integer, nothing can be smaller. */
6842 }
6844 /* Return true if GNAT_RANGE, a N_Range node, cannot be superflat, i.e. if the
6845 inequality HB >= LB - 1 is true. LB and HB are the low and high bounds. */
6847 static bool
6849 {
6851 Node_Id gnat_scalar_range;
6854 /* This is the easy case. */
6858 /* If the low bound is not constant, take the worst case by finding an upper
6859 bound for its type, repeatedly if need be. */
6868 /* If the high bound is not constant, take the worst case by finding a lower
6869 bound for its type, repeatedly if need be. */
6878 /* If we have failed to find constant bounds, punt. */
6883 /* We need at least a signed 64-bit type to catch most cases. */
6889 /* If the low bound is the smallest integer, nothing can be smaller. */
6895 }
6897 /* Return true if GNU_EXPR is (essentially) the address of a CONSTRUCTOR. */
6899 static bool
6901 {
6908 }
6910 /* Return true if the size in units represented by GNU_SIZE can be handled by
6911 an allocation. If STATIC_P is true, consider only what can be done with a
6912 static allocation. */
6914 static bool
6916 {
6917 /* We can allocate a fixed size if it is a valid for the middle-end but, for
6918 a static allocation, we do not allocate more than 2 GB because this would
6919 very likely be unintended and problematic for usual code models. */
6924 /* We can allocate a variable size if this isn't a static allocation. */
6925 else
6927 }
6929 /* Return true if GNU_EXPR needs a conversion to GNU_TYPE when used as the
6930 initial value of an object of GNU_TYPE. */
6932 static bool
6934 {
6935 /* Do not convert if the object's type is unconstrained because this would
6936 generate useless evaluations of the CONSTRUCTOR to compute the size. */
6941 /* Do not convert if the object's type is a padding record whose field is of
6942 self-referential size because we want to copy only the actual data. */
6946 /* Do not convert a call to a function that returns with variable size since
6947 we want to use the return slot optimization in this case. */
6952 /* Do not convert to a record type with a variant part from a record type
6953 without one, to keep the object simpler. */
6960 /* In all the other cases, convert the expression to the object's type. */
6962 }
6964 /* Add the contribution of [MIN, MAX] to the current number of elements N_ELEM
6965 of an array type and return the result, or NULL_TREE if it overflowed. */
6967 static tree
6969 {
6970 /* First deal with the empty case. */
6979 /* Compute the number of elements in this dimension. */
6980 tree this_n_elem
6986 /* Multiply the current number of elements by the result. */
6993 }
6995 /* Given GNAT_ENTITY, elaborate all expressions that are required to
6996 be elaborated at the point of its definition, but do nothing else. */
6998 void
7000 {
7002 {
7009 {
7013 /* ??? Tests to avoid Constraint_Error in static expressions
7014 are needed until after the front stops generating bogus
7015 conversions on bounds of real types. */
7023 }
7030 {
7031 Node_Id gnat_discriminant_expr;
7032 Entity_Id gnat_field;
7036 gnat_discriminant_expr
7041 /* Ignore access discriminants. */
7046 }
7049 /* -Wswitch warning avoidance. */
7052 }
7053 }
7055 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
7056 NAME, ARGS and ERROR_POINT. */
7058 static void
7061 tree attr_name,
7062 tree attr_args,
7063 Node_Id attr_error_point)
7064 {
7074 }
7076 /* Prepend to ATTR_LIST an entry for an attribute provided by GNAT_PRAGMA. */
7078 static void
7080 {
7086 /* Map the pragma at hand. Skip if this isn't one we know how to handle. */
7088 {
7119 }
7121 /* See what arguments we have and turn them into GCC trees for attribute
7122 handlers. The first one is always expected to be a string meant to be
7123 turned into an identifier. The next ones are all static expressions,
7124 among which strings meant to be turned into an identifier, except for
7125 a couple of specific attributes that require raw strings. */
7127 {
7132 const bool string_args
7142 {
7146 gnu_arg_list
7149 }
7150 }
7155 }
7157 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
7159 static void
7161 {
7162 Node_Id gnat_temp;
7164 /* Attributes are stored as Representation Item pragmas. */
7170 }
7172 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
7173 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
7174 return the GCC tree to use for that expression. S is the suffix to use
7175 if a variable needs to be created and DEFINITION is true if this is done
7176 for a definition of GNAT_ENTITY. If NEED_VALUE is true, we need a result;
7177 otherwise, we are just elaborating the expression for side-effects. If
7178 NEED_FOR_DEBUG is true, we need a variable for debugging purposes even
7179 if it isn't needed for code generation. */
7181 static tree
7184 {
7185 tree gnu_expr;
7187 /* If we already elaborated this expression (e.g. it was involved
7188 in the definition of a private type), use the old value. */
7192 /* If we don't need a value and this is static or a discriminant,
7193 we don't need to do anything. */
7200 /* If it's a static expression, we don't need a variable for debugging. */
7204 /* Otherwise, convert this tree to its GCC equivalent and elaborate it. */
7208 /* Save the expression in case we try to elaborate this entity again. Since
7209 it's not a DECL, don't check it. Don't save if it's a discriminant. */
7214 }
7216 /* Similar, but take a GNU expression and always return a result. */
7218 static tree
7221 {
7226 /* If GNU_EXPR contains a placeholder, just return it. We rely on the fact
7227 that an expression cannot contain both a discriminant and a variable. */
7231 /* If GNU_EXPR is neither a constant nor based on a read-only variable, make
7232 a variable that is initialized to contain the expression when the package
7233 containing the definition is elaborated. If this entity is defined at top
7234 level, replace the expression by the variable; otherwise use a SAVE_EXPR
7235 if this is necessary. */
7238 else
7239 {
7240 /* Skip any conversions and simple constant arithmetics to see if the
7241 expression is based on a read-only variable. */
7249 expr_variable_p
7250 = !(inner
7253 }
7255 /* We only need to use the variable if we are in a global context since GCC
7256 can do the right thing in the local case. However, when not optimizing,
7257 use it for bounds of loop iteration scheme to avoid code duplication. */
7258 use_variable = expr_variable_p
7259 && (expr_global_p
7260 || (!optimize
7261 && definition
7266 /* If the GNAT encodings are not used, we don't need a variable for debug
7267 info purposes if the expression is a constant or another variable, but
7268 we must be careful because we do not generate debug info for external
7269 variables so DECL_IGNORED_P is not stable across units. */
7273 || (!expr_public_p
7278 /* Now create it, possibly only for debugging purposes. */
7280 {
7281 /* The following variable creation can happen when processing the body
7282 of subprograms that are defined outside of the extended main unit and
7283 inlined. In this case, we are not at the global scope, and thus the
7284 new variable must not be tagged "external", as we used to do here as
7285 soon as DEFINITION was false. And note that we test Needs_Debug_Info
7286 here instead of NEED_FOR_DEBUG because, once the variable is created,
7287 whether or not debug information is generated for it is orthogonal to
7288 the reason why it was created in the first place. */
7289 tree gnu_decl
7297 /* Using this variable for debug (if need_for_debug is true) requires
7298 a proper location. The back-end will compute a location for this
7299 variable only if the variable is used by the generated code.
7300 Returning the variable ensures the caller will use it in generated
7301 code. Note that there is no need for a location if the debug info
7302 contains an integer constant. */
7305 }
7308 }
7310 /* Similar, but take an alignment factor and make it explicit in the tree. */
7312 static tree
7315 {
7317 return
7320 gnu_expr,
7321 unit_align),
7323 need_for_debug),
7324 unit_align);
7325 }
7327 /* Structure to hold internal data for elaborate_reference. */
7329 struct er_data
7330 {
7331 Entity_Id entity;
7334 };
7336 /* Wrapper function around elaborate_expression_1 for elaborate_reference. */
7338 static tree
7340 {
7344 /* This is what elaborate_expression_1 does if NEED_DEBUG is false. */
7348 /* If this is a COMPONENT_REF of a fat pointer, elaborate the entire fat
7349 pointer. This may be more efficient, but will also allow us to more
7350 easily find the match for the PLACEHOLDER_EXPR. */
7357 /* If this is the displacement of a pointer, elaborate the pointer and then
7358 displace the result. The actual purpose here is to drop the location on
7359 the expression, which may be problematic if replicated on references. */
7367 return
7369 }
7371 /* Elaborate the reference REF to be used as renamed object for GNAT_ENTITY.
7372 DEFINITION is true if this is done for a definition of GNAT_ENTITY and
7373 INIT is set to the first arm of a COMPOUND_EXPR present in REF, if any. */
7375 static tree
7378 {
7381 }
7383 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
7384 the value passed against the list of choices. */
7386 static tree
7388 {
7397 {
7399 tree gnu_test;
7402 {
7417 /* This represents either a subtype range or a static value of
7418 some kind; Ekind says which. */
7420 {
7426 }
7428 /* ... fall through ... */
7440 }
7442 /* Everything should be folded into constants at this point. */
7452 gnu_test
7463 gnu_test
7466 else
7471 else
7472 gnu_result
7475 }
7478 }
7480 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
7481 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
7483 static int
7485 {
7486 /* If the field is an array of variable size, we'd better not pack it because
7487 this would misalign it and, therefore, probably cause large temporarie to
7488 be created in case we need to take its address. See addressable_p and the
7489 notes on the addressability issues for further details. */
7494 /* In the other cases, we can honor the packing. */
7498 /* If the alignment of the record is specified and the field type
7499 is over-aligned, request Storage_Unit alignment for the field. */
7504 /* Likewise if the maximum alignment of the record is specified. */
7510 }
7512 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
7513 placed in GNU_RECORD_TYPE.
7515 PACKED is 1 if the enclosing record is packed or -1 if the enclosing
7516 record has Component_Alignment of Storage_Unit.
7518 DEFINITION is true if this field is for a record being defined.
7520 DEBUG_INFO_P is true if we need to write debug information for types
7521 that we may create in the process. */
7523 static tree
7526 {
7533 const bool is_full_access
7535 const bool is_independent
7537 const bool is_volatile
7541 /* We used to consider that volatile fields also require strict alignment,
7542 but that was an interpolation and would cause us to reject a pragma
7543 volatile on a packed record type containing boolean components, while
7544 there is no basis to do so in the RM. In such cases, the writes will
7545 involve load-modify-store sequences, but that's OK for volatile. The
7546 only constraint is the implementation advice whereby only the bits of
7547 the components should be accessed if they both start and end on byte
7548 boundaries, but that should be guaranteed by the GCC memory model.
7549 Note that we have some redundancies (is_full_access => is_independent,
7550 is_aliased => is_independent and is_by_ref => is_strict_alignment)
7551 so the following formula is sufficient. */
7557 /* Force the type of the Not_Handled_By_Others field to be that of the
7558 field in struct Exception_Data declared in raise.h instead of using
7559 the declared boolean type. We need to do that because there is no
7560 easy way to make use of a C compatible boolean type for the latter. */
7565 /* The qualifier to be used in messages. */
7569 {
7573 else
7575 }
7582 else
7585 /* The message to be used for incompatible size. */
7591 /* If a field requires strict alignment, we cannot pack it (RM 13.2(7)). */
7594 else
7597 /* If a size is specified, use it. Otherwise, if the record type is packed,
7598 use the official RM size. See "Handling of Type'Size Values" in Einfo
7599 for further details. */
7604 {
7608 }
7609 else
7612 /* Likewise for the position. */
7614 {
7617 }
7619 /* If the record has rep clauses and this is the tag field, make a rep
7620 clause for it as well. */
7623 {
7627 }
7629 else
7630 {
7633 }
7635 /* If the field's type is a fixed-size record that does not require strict
7636 alignment, and the record is packed or we have a position specified for
7637 the field that makes it a bitfield or we have a specified size that is
7638 smaller than that of the field's type, then see if we can get either an
7639 integral mode form of the field's type or a smaller form. If we can,
7640 consider that a size was specified for the field if there wasn't one
7641 already, so we know to make it a bitfield and avoid making things wider.
7643 Changing to an integral mode form is useful when the record is packed as
7644 we can then place the field at a non-byte-aligned position and so achieve
7645 tighter packing. This is in addition required if the field shares a byte
7646 with another field and the front-end lets the back-end handle the access
7647 to the field, because GCC cannot handle non-byte-aligned BLKmode fields.
7649 Changing to a smaller form is required if the specified size is smaller
7650 than that of the field's type and the type contains sub-fields that are
7651 padded, in order to avoid generating accesses to these sub-fields that
7652 are wider than the field.
7654 We avoid the transformation if it is not required or potentially useful,
7655 as it might entail an increase of the field's alignment and have ripple
7656 effects on the outer record type. A typical case is a field known to be
7657 byte-aligned and not to share a byte with another field. */
7663 || is_bitfield
7664 || (gnu_size
7666 {
7667 tree gnu_packable_type
7670 {
7674 }
7675 }
7677 /* Now check if the type of the field allows atomic access. */
7679 {
7680 const unsigned int align
7683 gnu_field_type
7687 }
7689 /* If a position is specified, check that it is valid. */
7691 {
7694 /* Ensure the position doesn't overlap with the parent subtype if there
7695 is one. It would be impossible to build CONSTRUCTORs and accessing
7696 the parent could clobber the component in the extension if directly
7697 done. We accept it with -gnatd.K for the sake of compatibility. */
7700 {
7705 post_error_ne_tree
7708 }
7710 /* If this field needs strict alignment, make sure that the record is
7711 sufficiently aligned and that the position and size are consistent
7712 with the type. But don't do it if we are just annotating types and
7713 the field's type is tagged, since tagged types aren't fully laid out
7714 in this mode. Also, note that atomic implies volatile so the inner
7715 test sequences ordering is significant here. */
7718 {
7725 /* If the position is not a multiple of the storage unit, then error
7726 out and reset the position. */
7728 bitsize_unit_node)))
7729 {
7735 }
7737 /* If the position is not a multiple of the alignment of the type,
7738 then error out and reset the position. */
7742 {
7745 field_s);
7752 }
7755 {
7759 /* If the size is not a multiple of the storage unit, then error
7760 out and reset the size. */
7762 bitsize_unit_node)))
7763 {
7769 }
7771 /* If the size is lower than that of the type, or greater for
7772 atomic and aliased, then error out and reset the size. */
7775 {
7779 type_size);
7781 }
7782 }
7783 }
7784 }
7786 else
7787 {
7788 /* If we are packing the record and the field is BLKmode, round the
7789 size up to a byte boundary. */
7792 }
7794 /* We need to make the size the maximum for the type if it is
7795 self-referential and an unconstrained type. In that case, we can't
7796 pack the field since we can't make a copy to align it. */
7798 && !gnu_size
7801 {
7804 }
7806 /* If a size is specified, adjust the field's type to it. */
7808 {
7809 tree orig_field_type;
7811 /* If the field's type is justified modular, we would need to remove
7812 the wrapper to (better) meet the layout requirements. However we
7813 can do so only if the field is not aliased to preserve the unique
7814 layout, if it has the same storage order as the enclosing record
7815 and if the prescribed size is not greater than that of the packed
7816 array to preserve the justification. */
7826 /* Similarly if the field's type is a misaligned integral type, but
7827 there is no restriction on the size as there is no justification. */
7834 gnu_field_type
7838 /* If the type has been extended, we may need to cap the alignment. */
7848 /* For a bitfield, if the type still has BLKmode, try again to change it
7849 to an integral mode form. This may be necessary on strict-alignment
7850 platforms with a size clause that is much larger than the field type,
7851 because maybe_pad_type has preserved the alignment of the field type,
7852 which may be too low for the new size. */
7860 /* If a padding record was made, declare it now since it will never be
7861 declared otherwise. This is necessary to ensure that its subtrees
7862 are properly marked. */
7867 }
7869 /* Otherwise (or if there was an error), don't specify a position. */
7870 else
7873 /* If the field's type is a padded type made for a scalar field of a record
7874 type with reverse storage order, we need to propagate the reverse storage
7875 order to the padding type since it is the innermost enclosing aggregate
7876 type around the scalar. */
7885 /* Now create the decl for the field. */
7886 gnu_field
7893 /* If this is a discriminant, then we treat it specially: first, we set its
7894 index number for the back-annotation; second, we record whether it cannot
7895 be changed once it has been set for the computation of loop invariants;
7896 third, we make it addressable in order for the optimizer to more easily
7897 see that it cannot be modified by assignments to the other fields of the
7898 record (see create_field_decl for a more detailed explanation), which is
7899 crucial to hoist the offset and size computations of dynamic fields. */
7901 {
7907 }
7910 }
7912 /* Return true if at least one member of COMPONENT_LIST needs strict
7913 alignment. */
7915 static bool
7917 {
7918 Node_Id component_decl;
7923 {
7931 }
7934 }
7936 /* Return true if FIELD is an artificial field. */
7938 static bool
7940 {
7941 /* These fields are generated by the front-end proper. */
7945 /* These fields are generated by gigi. */
7950 }
7952 /* Return true if FIELD is a non-artificial field with self-referential
7953 size. */
7955 static bool
7957 {
7965 }
7967 /* Return true if FIELD is a non-artificial field with variable size. */
7969 static bool
7971 {
7979 }
7981 /* qsort comparer for the bit positions of two record components. */
7983 static int
7985 {
7988 const int ret
7992 }
7994 /* Sort the LIST of fields in reverse order of increasing position. */
7996 static tree
7998 {
8008 {
8011 }
8014 }
8016 /* Reverse function from gnat_to_gnu_field: return the GNAT field present in
8017 either GNAT_COMPONENT_LIST or the discriminants of GNAT_RECORD_TYPE, and
8018 corresponding to the GNU tree GNU_FIELD. */
8020 static Entity_Id
8022 Entity_Id gnat_record_type)
8023 {
8031 {
8035 }
8045 }
8047 /* Issue a warning for the problematic placement of GNU_FIELD present in
8048 either GNAT_COMPONENT_LIST or the discriminants of GNAT_RECORD_TYPE.
8049 IN_VARIANT is true if GNAT_COMPONENT_LIST is the list of a variant.
8050 DO_REORDER is true if fields of GNAT_RECORD_TYPE are being reordered. */
8052 static void
8056 {
8060 Entity_Id gnat_field
8065 = in_variant
8077 = do_reorder
8084 }
8086 /* Likewise but for every field present on GNU_FIELD_LIST. */
8088 static void
8092 {
8096 }
8098 /* Structure holding information for a given variant. */
8100 {
8101 /* The record type of the variant. */
8102 tree type;
8104 /* The name of the variant. */
8105 tree name;
8107 /* The qualifier of the variant. */
8108 tree qual;
8110 /* Whether the variant has a rep clause. */
8113 /* Whether the variant is packed. */
8118 /* Translate and chain GNAT_COMPONENT_LIST present in GNAT_RECORD_TYPE to
8119 GNU_FIELD_LIST, set the result as the field list of GNU_RECORD_TYPE and
8120 finish it up. Return true if GNU_RECORD_TYPE has a rep clause that affects
8121 the layout (see below). When called from gnat_to_gnu_entity during the
8122 processing of a record definition, the GCC node for the parent, if any,
8123 will be the single field of GNU_RECORD_TYPE and the GCC nodes for the
8124 discriminants will be on GNU_FIELD_LIST. The other call to this function
8125 is a recursive call for the component list of a variant and, in this case,
8126 GNU_FIELD_LIST is empty. Note that GNAT_COMPONENT_LIST may be Empty.
8128 PACKED is 1 if this is for a packed record or -1 if this is for a record
8129 with Component_Alignment of Storage_Unit.
8131 DEFINITION is true if we are defining this record type.
8133 CANCEL_ALIGNMENT is true if the alignment should be zeroed before laying
8134 out the record. This means the alignment only serves to force fields to
8135 be bitfields, but not to require the record to be that aligned. This is
8136 used for variants.
8138 ALL_REP is true if a rep clause is present for all the fields.
8140 UNCHECKED_UNION is true if we are building this type for a record with a
8141 Pragma Unchecked_Union.
8143 ARTIFICIAL is true if this is a type that was generated by the compiler.
8145 DEBUG_INFO is true if we need to write debug information about the type.
8147 IN_VARIANT is true if the componennt list is that of a variant.
8149 FIRST_FREE_POS, if nonzero, is the first (lowest) free field position in
8150 the outer record type down to this variant level. It is nonzero only if
8151 all the fields down to this level have a rep clause and ALL_REP is false.
8153 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
8154 with a rep clause is to be added; in this case, that is all that should
8155 be done with such fields and the return value will be false. */
8157 static bool
8164 {
8165 const bool needs_xv_encodings
8178 /* For each component referenced in a component declaration create a GCC
8179 field and add it to the list, skipping pragmas in the GNAT list. */
8187 {
8191 /* If present, the _Parent field must have been created as the single
8192 field of the record type. Put it before any other fields. */
8194 {
8197 }
8198 else
8199 {
8203 /* If this is the _Tag field, put it before any other fields. */
8207 /* If this is the _Controller field, put it before the other
8208 fields except for the _Tag or _Parent field. */
8210 {
8213 }
8215 /* If this is a regular field, put it after the other fields. */
8216 else
8217 {
8223 /* And record information for the final layout. */
8232 }
8233 }
8236 }
8238 /* At the end of the component list there may be a variant part. */
8241 else
8244 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
8245 mutually exclusive and should go in the same memory. To do this we need
8246 to treat each variant as a record whose elements are created from the
8247 component list for the variant. So here we create the records from the
8248 lists for the variants and put them all into the QUAL_UNION_TYPE.
8249 If this is an Unchecked_Union, we make a UNION_TYPE instead or
8250 use GNU_RECORD_TYPE if there are no fields so far. */
8252 {
8256 tree gnu_var_name
8259 tree gnu_union_name
8261 tree gnu_union_type;
8270 /* Reuse the enclosing union if this is an Unchecked_Union whose fields
8271 are all in the variant part, to match the layout of C unions. There
8272 is an associated check below. */
8275 else
8276 {
8277 gnu_union_type
8285 }
8287 /* If all the fields down to this level have a rep clause, find out
8288 whether all the fields at this level also have one. If so, then
8289 compute the new first free position to be passed downward. */
8292 {
8294 gnu_field;
8297 {
8300 this_first_free_pos
8302 }
8303 else
8304 {
8307 }
8308 }
8310 /* For an unchecked union with a fixed part, we need to compute whether
8311 we are at the innermost level of the variant part. */
8318 {
8321 }
8323 /* We build the variants in two passes. The bulk of the work is done in
8324 the first pass, that is to say translating the GNAT nodes, building
8325 the container types and computing the associated properties. However
8326 we cannot finish up the container types during this pass because we
8327 don't know where the variant part will be placed until the end. */
8331 {
8336 vinfo_t vinfo;
8344 /* Set the alignment of the inner type in case we need to make
8345 inner objects into bitfields, but then clear it out so the
8346 record actually gets only the alignment required. */
8352 /* Similarly, if the outer record has a size specified and all
8353 the fields have a rep clause, we can propagate the size. */
8355 {
8359 }
8361 /* Add the fields into the record type for the variant but note that
8362 we aren't sure to really use it at this point, see below. In the
8363 case of an unchecked union with a fixed part, we force the fields
8364 with a rep clause present in the innermost variant to be moved to
8365 the outer variant, so as to flatten the rep-ed layout as much as
8366 possible, the reason being that we cannot do any flattening when
8367 a subtype statically selects a variant later on, for example for
8368 an aggregate. */
8369 has_rep
8376 && !(unchecked_union
8377 && gnu_field_list
8381 /* Translate the qualifier and annotate the GNAT node. */
8385 /* Deal with packedness like in gnat_to_gnu_field. */
8387 {
8390 }
8391 else
8392 field_packed
8395 /* Push this variant onto the stack for the second pass. */
8403 /* Compute the global properties that will determine the placement of
8404 the variant part. */
8408 }
8410 /* Round up the first free position to the alignment of the variant part
8411 for the variants without rep clause. This will guarantee a consistent
8412 layout independently of the placement of the variant part. */
8416 /* In the second pass, the container types are adjusted if necessary and
8417 finished up, then the corresponding fields of the variant part are
8418 built with their qualifier, unless this is an unchecked union. */
8420 {
8424 /* If this is an Unchecked_Union whose fields are all in the variant
8425 part and we have a single field with no representation clause or
8426 placed at offset zero, use the field directly to match the layout
8427 of C unions. */
8429 && gnu_field_list
8433 {
8436 }
8437 else
8438 {
8439 /* Finalize the variant type now. We used to throw away empty
8440 record types but we no longer do that because we need them to
8441 generate complete debug info for the variant; otherwise, the
8442 union type definition will be lacking the fields associated
8443 with these empty variants. */
8445 {
8446 /* The variant part will be at offset 0 so we need to ensure
8447 that the fields are laid out starting from the first free
8448 position at this level. */
8450 tree gnu_rep_part;
8454 gnu_rep_part
8456 this_first_free_pos);
8461 }
8468 gnu_field
8470 gnu_union_type,
8471 all_rep_and_size
8480 }
8484 }
8486 /* Only make the QUAL_UNION_TYPE if there are non-empty variants. */
8488 {
8492 {
8496 }
8501 /* If GNU_UNION_TYPE is our record type, this means that we must have
8502 an Unchecked_Union whose fields are all in the variant part. Now
8503 verify that and, if so, just return. */
8505 {
8507 && !gnu_field_list
8510 }
8515 /* Deal with packedness like in gnat_to_gnu_field. */
8518 else
8519 union_field_packed
8522 gnu_variant_part
8524 all_rep_and_size
8530 }
8531 }
8533 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they do,
8534 pull them out and put them onto the appropriate list.
8536 Similarly, pull out the fields with zero size and no rep clause, as they
8537 would otherwise modify the layout and thus very likely run afoul of the
8538 Ada semantics, which are different from those of C here.
8540 Finally, if there is an aliased field placed in the list after fields
8541 with self-referential size, pull out the latter in the same way.
8543 Optionally, if the reordering mechanism is enabled, pull out the fields
8544 with self-referential size, variable size and fixed size not a multiple
8545 of a byte, so that they don't cause the regular fields to be either at
8546 self-referential/variable offset or misaligned. Note, in the latter
8547 case, that this can only happen in packed record types so the alignment
8548 is effectively capped to the byte for the whole record. But we don't
8549 do it for packed record types if not all fixed-size fiels can be packed
8550 and for non-packed record types if pragma Optimize_Alignment (Space) is
8551 specified, because this can prevent alignment gaps from being filled.
8553 Optionally, if the layout warning is enabled, keep track of the above 4
8554 different kinds of fields and issue a warning if some of them would be
8555 (or are being) reordered by the reordering mechanism.
8557 ??? If we reorder fields, the debugging information will be affected and
8558 the debugger print fields in a different order from the source code. */
8559 const bool do_reorder
8563 ? has_non_packed_fixed_size_field
8566 const bool w_reorder
8579 #define MOVE_FROM_FIELD_LIST_TO(LIST) \
8580 do { \
8581 if (gnu_last) \
8582 DECL_CHAIN (gnu_last) = gnu_next; \
8583 else \
8584 gnu_field_list = gnu_next; \
8585 \
8586 DECL_CHAIN (gnu_field) = (LIST); \
8587 (LIST) = gnu_field; \
8588 } while (0)
8592 {
8596 {
8599 }
8602 {
8613 }
8616 {
8619 }
8621 /* We don't need further processing in default mode. */
8623 {
8626 }
8629 {
8631 {
8635 do_reorder);
8636 else
8638 }
8641 {
8644 }
8645 }
8648 {
8650 {
8654 do_reorder);
8655 else
8657 }
8660 {
8663 }
8664 }
8666 else
8667 {
8668 /* If the field has no size, then it cannot be bit-packed. */
8669 const unsigned int bitp_size
8674 /* If the field is bit-packed, we move it to a temporary list that
8675 contains the contiguously preceding bit-packed fields, because
8676 we want to be able to put them back if the misalignment happens
8677 to cancel itself after several bit-packed fields. */
8679 {
8683 {
8686 }
8689 {
8692 }
8693 }
8695 /* No more bit-packed fields, move the existing ones to the end or
8696 put them back at their original location. */
8698 {
8702 {
8704 {
8707 gnat_component_list,
8709 do_reorder);
8710 else
8712 gnat_component_list,
8714 do_reorder);
8715 }
8722 }
8723 else
8724 {
8725 /* Rechain the temporary list in front of GNU_FIELD. */
8728 {
8733 else
8737 }
8738 }
8739 }
8741 else
8743 }
8746 }
8748 #undef MOVE_FROM_FIELD_LIST_TO
8752 /* If permitted, we reorder the fields as follows:
8754 1) all (groups of) fields whose length is fixed and multiple of a byte,
8755 2) the remaining fields whose length is fixed and not multiple of a byte,
8756 3) the remaining fields whose length doesn't depend on discriminants,
8757 4) all fields whose length depends on discriminants,
8758 5) the variant part,
8760 within the record and within each variant recursively. */
8763 {
8764 /* If we have pending bit-packed fields, warn if they would be moved
8765 to after regular fields. */
8769 {
8774 else
8778 }
8779 }
8782 {
8783 /* If we have pending bit-packed fields on the temporary list, we put
8784 them either on the bit-packed list or back on the regular list. */
8786 {
8789 else
8791 }
8793 gnu_field_list
8797 }
8799 /* Otherwise, if there is an aliased field placed after a field whose length
8800 depends on discriminants, we put all the fields of the latter sort, last.
8801 We need to do this in case an object of this record type is mutable. */
8805 /* If P_REP_LIST is nonzero, this means that we are asked to move the fields
8806 in our REP list to the previous level because this level needs them in
8807 order to do a correct layout, i.e. avoid having overlapping fields. */
8811 /* Deal with the case of an extension of a record type with variable size and
8812 partial rep clause, for which the _Parent field is forced at offset 0 and
8813 has variable size. Note that we cannot do it if the field has fixed size
8814 because we rely on the presence of the REP part built below to trigger the
8815 reordering of the fields in a derived record type when all the fields have
8816 a fixed position. */
8820 && !variants_have_rep
8821 && first_free_pos
8824 {
8828 }
8830 /* Otherwise, sort the fields by bit position and put them into their own
8831 record, before the others, if we also have fields without rep clause. */
8833 {
8836 /* If all the fields have a rep clause, we can do a flat layout. */
8837 layout_with_rep = !gnu_field_list
8840 /* Same as above but the extension itself has a rep clause, in which case
8841 we need to set aside the _Parent field to lay out the REP part. */
8843 && !layout_with_rep
8844 && !variants_have_rep
8845 && first_free_pos
8848 {
8851 }
8852 else
8855 gnu_rep_type
8858 /* Sort the fields in order of increasing bit position. */
8864 {
8867 }
8873 {
8877 }
8879 /* Do the layout of the REP part, if any. */
8882 else
8883 {
8890 /* If FIRST_FREE_POS is nonzero, we need to ensure that the fields
8891 without rep clause are laid out starting from this position.
8892 Therefore, we force it as a minimal size on the REP part. */
8893 tree gnu_rep_part
8896 /* If this is an extension, put back the _Parent field as the first
8897 field of the REP part at offset 0 and update its layout. */
8899 {
8905 {
8912 }
8913 }
8918 /* Chain the REP part at the beginning of the field list. */
8921 }
8922 }
8924 /* Chain the variant part at the end of the field list. */
8936 /* Chain the fields with zero size at the beginning of the field list. */
8942 }
8944 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
8945 placed into an Esize, Component_Bit_Offset, or Component_Size value
8946 in the GNAT tree. */
8948 static Uint
8950 {
8952 TCode tcode;
8956 /* See if we've already saved the value for this node. */
8958 {
8966 }
8967 else
8970 /* If we do not return inside this switch, TCODE will be set to the
8971 code to be used in a call to Create_Node. */
8973 {
8975 /* For negative values, build NEGATE_EXPR of the opposite. Such values
8976 can appear for discriminants in expressions for variants. */
8978 {
8982 }
8983 else
8988 /* The only case we handle here is a simple discriminant reference. */
8990 {
8994 /* Climb up the chain of successive extensions, if any. */
9001 {
9002 /* Fall through to common processing as a FIELD_DECL. */
9005 }
9006 else
9008 }
9009 else
9019 CASE_CONVERT:
9023 /* Now just list the operations we handle. */
9051 /* Turn addition of negative constant into subtraction. */
9054 {
9059 }
9061 /* ... fall through ... */
9065 /* Fold conversions from bytes to bits into inner operations. */
9068 {
9072 {
9076 widest_int op1;
9080 else
9081 {
9086 }
9088 }
9089 }
9094 /* For negative values in sizetype, build NEGATE_EXPR of the opposite.
9095 Such values can appear in expressions with aligning patterns. */
9097 {
9101 }
9105 /* In regular mode, inline back only if symbolic annotation is requested
9106 in order to avoid memory explosion on big discriminated record types.
9107 But not in ASIS mode, as symbolic annotation is required for DDA. */
9109 {
9112 }
9113 else
9118 }
9120 /* Now get each of the operands that's relevant for this code. If any
9121 cannot be expressed as a repinfo node, say we can't. */
9124 {
9128 }
9132 /* Save the result in the cache. */
9134 {
9136 /* We can't assume the hash table data hasn't moved since the initial
9137 look up, so we have to search again. Allocating and inserting an
9138 entry at that point would be an alternative, but then we'd better
9139 discard the entry if we decided not to cache it. */
9145 }
9148 }
9150 /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
9151 and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
9152 size and alignment used by Gigi. Prefer SIZE over TYPE_SIZE if non-null.
9153 BY_REF is true if the object is used by reference. */
9155 void
9157 {
9159 {
9162 else
9164 }
9167 {
9176 }
9181 }
9183 /* Return first element of field list whose TREE_PURPOSE is the same as ELEM.
9184 Return NULL_TREE if there is no such element in the list. */
9186 static tree
9188 {
9190 {
9195 }
9197 }
9199 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding GCC type,
9200 set Component_Bit_Offset and Esize of the components to the position and
9201 size used by Gigi. */
9203 static void
9205 {
9206 /* For an extension, the inherited components have not been translated because
9207 they are fetched from the _Parent component on the fly. */
9208 const bool is_extension
9211 /* We operate by first making a list of all fields and their position (we
9212 can get the size easily) and then update all the sizes in the tree. */
9213 tree gnu_list
9224 {
9226 gnu_list);
9228 {
9232 /* If we are just annotating types and the type is tagged, the tag
9233 and the parent components are not generated by the front-end so
9234 we need to add the appropriate offset to each component without
9235 representation clause. */
9239 {
9240 tree parent_bit_offset;
9242 /* For a component appearing in the current extension, the
9243 offset is the size of the parent. */
9246 parent_bit_offset
9248 bitsizetype);
9249 else
9253 parent_bit_offset
9257 offset
9261 parent_bit_offset,
9262 bitsize_unit_node)));
9263 }
9265 /* If the field has a variable offset, also compute the normalized
9266 position since it's easier to do on trees here than to deduce
9267 it from the annotated expression of Component_Bit_Offset. */
9269 {
9275 }
9277 Set_Component_Bit_Offset
9281 Set_Esize
9284 }
9286 {
9287 /* If there is no entry, this is an inherited component whose
9288 position is the same as in the parent type. */
9291 /* If we are just annotating types, discriminants renaming those of
9292 the parent have no entry so deal with them specifically. */
9299 {
9304 }
9310 }
9311 }
9312 }
9314 /* Scan all fields in GNU_TYPE and return a TREE_LIST where TREE_PURPOSE is
9315 the FIELD_DECL and TREE_VALUE a TREE_VEC containing the byte position, the
9316 value to be placed into DECL_OFFSET_ALIGN and the bit position. The list
9317 of fields is flattened, except for variant parts if DO_NOT_FLATTEN_VARIANT
9318 is set to true. GNU_POS is to be added to the position, GNU_BITPOS to the
9319 bit position, OFFSET_ALIGN is the present offset alignment. GNU_LIST is a
9320 pre-existing list to be chained to the newly created entries. */
9322 static tree
9325 {
9326 tree gnu_field;
9329 gnu_field;
9331 {
9336 unsigned int our_offset_align
9345 /* Recurse on internal fields, flattening the nested fields except for
9346 those in the variant part, if requested. */
9348 {
9352 gnu_list
9356 else
9357 gnu_list
9361 }
9362 }
9365 }
9367 /* Return a list describing the substitutions needed to reflect the
9368 discriminant substitutions from GNAT_TYPE to GNAT_SUBTYPE. They can
9369 be in any order. The values in an element of the list are in the form
9370 of operands to SUBSTITUTE_IN_EXPR. DEFINITION is true if this is for
9371 a definition of GNAT_SUBTYPE. */
9375 {
9377 Entity_Id gnat_discrim;
9378 Node_Id gnat_constr;
9385 /* Ignore access discriminants. */
9387 {
9389 tree replacement
9393 /* If this is a definition, we need to make sure that the SAVE_EXPRs
9394 are instantiated on every possibly path in size computations. */
9400 }
9403 }
9405 /* Scan all fields in {GNU_QUAL_UNION_TYPE,GNAT_VARIANT_PART} and return a list
9406 describing the variants of GNU_QUAL_UNION_TYPE that are still relevant after
9407 applying the substitutions described in SUBST_LIST. GNU_LIST is an existing
9408 list to be prepended to the newly created entries. */
9413 {
9414 Node_Id gnat_variant;
9415 tree gnu_field;
9418 gnat_variant
9422 gnu_field;
9424 gnat_variant
9428 {
9436 /* If the new qualifier is not unconditionally false, its variant may
9437 still be accessed. */
9439 {
9441 variant_desc v
9446 /* Annotate the GNAT node if present. */
9450 /* Recurse on the variant subpart of the variant, if any. */
9453 gnu_list
9456 ? Variant_Part
9459 subst_list,
9460 gnu_list);
9462 /* If the new qualifier is unconditionally true, the subsequent
9463 variants cannot be accessed. */
9466 }
9467 }
9470 }
9472 /* If SIZE has overflowed, return the maximum valid size, which is the upper
9473 bound of the signed sizetype in bits, rounded down to ALIGN. Otherwise
9474 return SIZE unmodified. */
9476 static tree
9478 {
9480 {
9481 size
9486 }
9489 }
9491 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
9492 corresponding to GNAT_OBJECT. If the size is valid, return an INTEGER_CST
9493 corresponding to its value. Otherwise, return NULL_TREE. KIND is set to
9494 VAR_DECL if we are specifying the size of an object, TYPE_DECL for the
9495 size of a type, and FIELD_DECL for the size of a field. COMPONENT_P is
9496 true if we are being called to process the Component_Size of GNAT_OBJECT;
9497 this is used only for error messages. ZERO_OK is true if a size of zero
9498 is permitted; if ZERO_OK is false, it means that a size of zero should be
9499 treated as an unspecified size. S1 and S2 are used for error messages. */
9501 static tree
9505 {
9506 Node_Id gnat_error_node;
9509 /* Return 0 if no size was specified. */
9513 /* Ignore a negative size since that corresponds to our back-annotation. */
9517 /* Find the node to use for error messages. */
9526 else
9529 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
9530 but cannot be represented in bitsizetype. */
9533 {
9536 gnat_object);
9537 else
9539 gnat_object);
9541 }
9543 /* Ignore a zero size if it is not permitted. */
9547 /* The size of objects is always a multiple of a byte. */
9550 {
9554 else
9558 }
9560 /* If this is an integral type or a bit-packed array type, the front-end has
9561 already verified the size, so we need not do it again (which would mean
9562 checking against the bounds). However, if this is an aliased object, it
9563 may not be smaller than the type of the object. */
9568 /* If the object is a record that contains a template, add the size of the
9569 template to the specified size. */
9576 /* If the old size is self-referential, get the maximum size. */
9580 /* If this is an access type or a fat pointer, the minimum size is that given
9581 by the smallest integral mode that's valid for pointers. */
9583 {
9588 }
9590 /* Issue an error either if the default size of the object isn't a constant
9591 or if the new size is smaller than it. */
9594 {
9599 {
9602 }
9605 else
9611 }
9614 }
9616 /* Similarly, but both validate and process a value of RM size. This routine
9617 is only called for types. */
9619 static void
9621 {
9622 Node_Id gnat_attr_node;
9625 /* Do nothing if no size was specified. */
9629 /* Only issue an error if a Value_Size clause was explicitly given for the
9630 entity; otherwise, we'd be duplicating an error on the Size clause. */
9631 gnat_attr_node
9636 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
9637 but cannot be represented in bitsizetype. */
9640 {
9643 gnat_entity);
9645 }
9647 /* Ignore a zero size unless a Value_Size clause exists, or a size clause
9648 exists, or this is an integer type, in which case the front-end will
9649 have always set it. */
9658 /* If the old size is self-referential, get the maximum size. */
9662 /* Issue an error either if the old size of the object isn't a constant or
9663 if the new size is smaller than it. The front-end has already verified
9664 this for scalar and bit-packed array types. */
9672 {
9674 post_error_ne_tree
9678 }
9680 /* Otherwise, set the RM size proper for integral types... */
9687 /* ...or the Ada size for record and union types. */
9691 }
9693 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
9694 a type or object whose present alignment is ALIGN. If this alignment is
9695 valid, return it. Otherwise, give an error and return ALIGN. */
9697 static unsigned int
9699 {
9702 Node_Id gnat_error_node;
9704 /* Don't worry about checking alignment if alignment was not specified
9705 by the source program and we already posted an error for this entity. */
9709 /* Post the error on the alignment clause if any. Note, for the implicit
9710 base type of an array type, the alignment clause is on the first
9711 subtype. */
9719 gnat_error_node =
9722 else
9725 /* Within GCC, an alignment is an integer, so we must make sure a value is
9726 specified that fits in that range. Also, there is an upper bound to
9727 alignments we can support/allow. */
9735 {
9739 /* If the default alignment of "double" or larger scalar types is
9740 specifically capped and the new alignment is above the cap, do
9741 not post an error and change the alignment only if there is an
9742 alignment clause; this makes it possible to have the associated
9743 GCC type overaligned by default for performance reasons. */
9745 {
9746 Entity_Id gnat_type
9748 is_capped_double
9750 }
9752 {
9753 Entity_Id gnat_type
9755 is_capped_double
9757 }
9758 else
9762 {
9765 }
9766 else
9767 {
9774 }
9775 }
9776 else
9777 {
9781 }
9784 }
9786 /* Promote the alignment of GNU_TYPE for an object with GNU_SIZE corresponding
9787 to GNAT_ENTITY. Return a positive value on success or zero on failure. */
9789 static unsigned int
9791 {
9794 /* No point in promoting the alignment if this doesn't prevent BLKmode access
9795 to the object, in particular block copy, as this will for example disable
9796 the NRV optimization for it. No point in jumping through all the hoops
9797 needed in order to support BIGGEST_ALIGNMENT if we don't really have to.
9798 So we cap to the smallest alignment that corresponds to a known efficient
9799 memory access pattern, except for a full access entity. */
9801 {
9804 }
9805 else
9806 {
9809 }
9814 /* Do the promotion within the above limits. */
9820 else
9823 /* But make sure not to under-align the object. */
9827 /* And honor the minimum valid atomic alignment, if any. */
9828 #ifdef MINIMUM_ATOMIC_ALIGNMENT
9831 #endif
9834 }
9836 /* Return whether GNAT_ENTITY is a simple constant, i.e. it represents only
9837 its value and reading it has no side effects. */
9839 bool
9841 {
9847 }
9849 /* Verify that TYPE is something we can implement atomically. If not, issue
9850 an error for GNAT_ENTITY. COMPONENT_P is true if we are being called to
9851 process a component type. */
9853 static void
9855 {
9857 Node_Id gnat_node;
9858 machine_mode mode;
9861 tree size;
9863 /* If this is an anonymous base type, nothing to check, the error will be
9864 reported on the source type if need be. */
9873 /* Consider all aligned floating-point types atomic and any aligned types
9874 that are represented by integers no wider than a machine word. */
9875 scalar_int_mode int_mode;
9882 /* For the moment, also allow anything that has an alignment equal to its
9883 size and which is smaller than a word. */
9894 {
9895 const Pragma_Id pragma_id
9900 {
9903 }
9904 }
9912 else
9915 }
9917 /* Return true if TYPE is suitable for a type-generic atomic builtin. */
9919 static bool
9921 {
9926 scalar_int_mode imode;
9931 }
9933 /* Return the GCC atomic builtin based on CODE and sized for TYPE. */
9935 static tree
9937 {
9942 }
9944 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
9945 on the Ada/builtin argument lists for the INB binding. */
9947 static bool
9949 {
9955 /* Sequence position of the last argument we checked. */
9959 {
9963 /* If we've exhausted both lists simultaneously, we're done. */
9967 /* If the internal builtin uses a variable list, accept anything. */
9971 /* If we're done with the Ada args and not with the internal builtin
9972 args, or the other way around, complain. */
9974 {
9977 }
9980 {
9984 }
9986 /* Otherwise, check that types match for the current argument. */
9987 argpos++;
9989 {
9990 /* For vector builtins, issue an error to avoid an ICE. */
9992 post_error_ne_num
9995 else
9996 post_error_ne_num
10000 }
10005 }
10008 }
10010 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
10011 on the Ada/builtin return values for the INB binding. */
10013 static bool
10015 {
10019 /* Accept function imported as procedure, common and convenient. */
10023 /* Check return types compatibility otherwise. Note that this
10024 handles void/void as well. */
10026 {
10027 /* For vector builtins, issue an error to avoid an ICE. */
10031 else
10035 }
10038 }
10040 /* Check and return whether the Ada and gcc builtin profiles bound by INB are
10041 compatible. Issue relevant warnings when they are not.
10043 This is intended as a light check to diagnose the most obvious cases, not
10044 as a full fledged type compatibility predicate. It is the programmer's
10045 responsibility to ensure correctness of the Ada declarations in Imports,
10046 especially when binding straight to a compiler internal. */
10048 static bool
10050 {
10051 /* Check compatibility on return values and argument lists, each responsible
10052 for posting warnings as appropriate. Ensure use of the proper sloc for
10053 this purpose. */
10066 }
10068 /* Return a FIELD_DECL node modeled on OLD_FIELD. FIELD_TYPE is its type
10069 and RECORD_TYPE is the type of the parent. If SIZE is nonzero, it is the
10070 specified size for this field. POS_LIST is a position list describing
10071 the layout of OLD_FIELD and SUBST_LIST a substitution list to be applied
10072 to this layout. */
10074 static tree
10078 {
10090 /* If the position is now a constant, we can set it as the position of the
10091 field when we make it. Otherwise, we need to deal with it specially. */
10094 else
10097 new_field
10103 {
10105 /* Finalize the position. */
10114 }
10122 }
10124 /* Create the REP part of RECORD_TYPE with REP_TYPE. If MIN_SIZE is nonzero,
10125 it is the minimal size the REP_PART must have. */
10127 static tree
10129 {
10130 tree field;
10140 }
10142 /* Return the REP part of RECORD_TYPE, if any. Otherwise return NULL. */
10144 static tree
10146 {
10149 /* The REP part is the first field, internal, another record, and its name
10150 starts with an 'R'. */
10158 }
10160 /* Return the variant part of RECORD_TYPE, if any. Otherwise return NULL. */
10162 tree
10164 {
10165 tree field;
10167 /* The variant part is the only internal field that is a qualified union. */
10174 }
10176 /* Return a new variant part modeled on OLD_VARIANT_PART. VARIANT_LIST is
10177 the list of variants to be used and RECORD_TYPE is the type of the parent.
10178 POS_LIST is a position list describing the layout of fields present in
10179 OLD_VARIANT_PART and SUBST_LIST a substitution list to be applied to this
10180 layout. DEBUG_INFO_P is true if we need to write debug information. */
10182 static tree
10188 {
10196 /* First create the type of the variant part from that of the old one. */
10202 /* If the position of the variant part is constant, subtract it from the
10203 size of the type of the parent to get the new size. This manual CSE
10204 reduces the code size when not optimizing. */
10208 {
10218 first_bit));
10221 }
10222 else
10225 /* Now finish up the new variants and populate the union type. */
10227 {
10231 /* Skip variants that don't belong to this nesting level. */
10235 /* Retrieve the list of fields already added to the new variant. */
10239 /* If the old variant had a variant subpart, we need to create a new
10240 variant subpart and add it to the field list. */
10244 {
10245 tree new_variant_subpart
10248 debug_info_p);
10251 }
10253 /* Finish up the new variant and create the field. */
10258 new_field
10266 }
10268 /* Finish up the union type and create the variant part. Note that we don't
10269 reverse the field list because VARIANT_LIST has been traversed in reverse
10270 order. */
10275 new_variant_part
10281 /* With multiple discriminants it is possible for an inner variant to be
10282 statically selected while outer ones are not; in this case, the list
10283 of fields of the inner variant is not flattened and we end up with a
10284 qualified union with a single member. Drop the useless container. */
10286 {
10295 }
10298 }
10300 /* Copy the size (and alignment and alias set) from OLD_TYPE to NEW_TYPE,
10301 which are both RECORD_TYPE, after applying the substitutions described
10302 in SUBST_LIST. */
10304 static void
10307 {
10331 SET_TYPE_ADA_SIZE
10335 /* Finalize the size. */
10338 }
10340 /* Return true if DISC is a stored discriminant of RECORD_TYPE. */
10344 {
10351 else
10353 }
10355 /* Copy the layout from {GNAT,GNU}_OLD_TYPE to {GNAT,GNU}_NEW_TYPE, which are
10356 both record types, after applying the substitutions described in SUBST_LIST.
10357 DEBUG_INFO_P is true if we need to write debug information for NEW_TYPE. */
10359 static void
10361 Entity_Id gnat_old_type,
10362 tree gnu_new_type,
10363 tree gnu_old_type,
10366 {
10373 /* Look for REP and variant parts in the old type. */
10377 /* If there is a variant part, we must compute whether the constraints
10378 statically select a particular variant. If so, we simply drop the
10379 qualified union and flatten the list of fields. Otherwise we will
10380 build a new qualified union for the variants that are still relevant. */
10382 {
10387 gnu_variant_list
10389 is_subtype
10390 ? Empty
10391 : Variant_Part
10393 subst_list,
10394 vNULL);
10396 /* If all the qualifiers are unconditionally true, the innermost variant
10397 is statically selected. */
10401 {
10404 }
10406 /* Otherwise, create the new variants. */
10409 {
10412 tree suffix
10422 }
10423 }
10424 else
10425 {
10428 }
10430 /* Make a list of fields and their position in the old type. */
10431 tree gnu_pos_list
10437 /* Now go down every component in the new type and compute its size and
10438 position from those of the component in the old type and the stored
10439 constraints of the new type. */
10452 {
10462 /* If the type is the same, retrieve the GCC type from the
10463 old field to take into account possible adjustments. */
10466 else
10469 /* If there was a component clause, the field types must be the same
10470 for the old and new types, so copy the data from the old field to
10471 avoid recomputation here. Also if the field is justified modular
10472 and the optimization in gnat_to_gnu_field was applied. */
10478 {
10481 }
10483 /* If the old field was packed and of constant size, we have to get the
10484 old size here as it might differ from what the Etype conveys and the
10485 latter might overlap with the following field. Try to arrange the
10486 type for possible better packing along the way. */
10489 {
10495 }
10497 else
10500 /* If the context of the old field is the old type or its REP part,
10501 put the field directly in the new type; otherwise look up the
10502 context in the variant list and put the field either in the new
10503 type if there is a selected variant or in one new variant. */
10507 else
10508 {
10510 tree rep_part;
10520 else
10521 /* The front-end may pass us zombie components if it fails to
10522 recognize that a constrain statically selects a particular
10523 variant. Discard them. */
10525 }
10527 /* Now create the new field modeled on the old one. */
10528 gnu_field
10534 /* If the context is a variant, put it in the new variant directly. */
10536 {
10538 {
10541 }
10542 else
10543 {
10546 }
10547 }
10549 /* To match the layout crafted in components_to_record, if this is
10550 the _Tag or _Parent field, put it before any other fields. */
10554 /* Similarly, if this is the _Controller field, put it before the
10555 other fields except for the _Tag or _Parent field. */
10557 {
10560 }
10562 /* Otherwise, put it after the other fields. */
10563 else
10564 {
10566 {
10571 }
10572 else
10573 {
10576 }
10577 }
10579 /* For a stored discriminant in a derived type, replace the field. */
10581 {
10584 }
10585 else
10587 }
10589 /* Put the fields with fixed position in order of increasing position. */
10593 /* Put the fields with variable position at the end. */
10597 /* If there is a variant list and no selected variant, we need to create the
10598 nest of variant parts from the old nest. */
10600 {
10604 /* Same processing as above for the fields of each variant. */
10606 {
10613 }
10615 tree new_variant_part
10621 }
10626 /* If NEW_TYPE is a subtype, it inherits all the attributes from OLD_TYPE.
10627 Otherwise sizes and alignment must be computed independently. */
10631 /* Now go through the entities again looking for itypes that we have not yet
10632 elaborated (e.g. Etypes of fields that have Original_Components). */
10641 }
10643 /* Associate to the implementation type of a packed array type specified by
10644 GNU_TYPE, which is the translation of GNAT_ENTITY, the original array type
10645 if it has been translated. This association is a parallel type for GNAT
10646 encodings or a debug type for standard DWARF. Note that for standard DWARF,
10647 we also want to get the original type name and therefore we return it. */
10649 static tree
10651 {
10652 const Entity_Id gnat_original_array_type
10654 tree gnu_original_array_type;
10667 {
10670 }
10671 else
10672 {
10679 }
10680 }
10682 /* Given a type T, a FIELD_DECL F, and a replacement value R, return an
10683 equivalent type with adjusted size expressions where all occurrences
10684 of references to F in a PLACEHOLDER_EXPR have been replaced by R.
10686 The function doesn't update the layout of the type, i.e. it assumes
10687 that the substitution is purely formal. That's why the replacement
10688 value R must itself contain a PLACEHOLDER_EXPR. */
10690 tree
10692 {
10693 tree nt;
10698 {
10704 /* First the domain types of arrays. */
10707 {
10719 SET_TYPE_INDEX_TYPE
10723 }
10725 /* Then the subtypes. */
10728 {
10740 }
10753 /* These should never show up here. */
10757 {
10777 }
10782 {
10784 tree field;
10786 /* Start out with no fields, make new fields, and chain them
10787 in. If we haven't actually changed the type of any field,
10788 discard everything we've done and return the old type. */
10793 {
10798 {
10801 }
10805 {
10808 }
10810 /* Do the substitution inside the qualifier, if any. */
10812 {
10815 {
10818 }
10819 }
10826 }
10836 }
10840 }
10841 }
10843 /* Return the RM size of GNU_TYPE. This is the actual number of bits
10844 needed to represent the object. */
10846 tree
10848 {
10849 /* For integral types, we store the RM size explicitly. */
10853 /* If the type contains a template, return the padded size of the template
10854 plus the RM size of the actual data. */
10857 return
10862 /* For record or union types, we store the size explicitly. */
10868 /* For other types, this is just the size. */
10870 }
10872 /* Return the name to be used for GNAT_ENTITY. If a type, create a
10873 fully-qualified name, possibly with type information encoding.
10874 Otherwise, return the name. */
10878 {
10881 }
10883 tree
10885 {
10888 }
10890 /* Return an identifier representing the external name to be used for
10891 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
10892 and the specified suffix. */
10894 tree
10896 {
10904 /* A variable using the Stdcall convention lives in a DLL. We adjust
10905 its name to use the jump table, the _imp__NAME contains the address
10906 for the NAME variable. */
10909 {
10915 }
10918 }
10920 /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
10921 string, return a new IDENTIFIER_NODE that is the concatenation of
10922 the name followed by "___" and the specified suffix. */
10924 tree
10926 {
10933 }
10935 /* Initialize the data structures of the decl.cc module. */
10937 void
10939 {
10940 /* Initialize the cache of annotated values. */
10943 /* Initialize the association of dummy types with subprograms. */
10945 }
10947 /* Destroy the data structures of the decl.cc module. */
10949 void
10951 {
10952 /* Destroy the cache of annotated values. */
10956 /* Destroy the association of dummy types with subprograms. */
10959 }