| blob | 60dc32c9cd040964f49b639f32bf7e86b2354ff6 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2016, 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 ****************************************************************************/
54 /* "stdcall" and "thiscall" conventions should be processed in a specific way
55 on 32-bit x86/Windows only. The macros below are helpers to avoid having
56 to check for a Windows specific attribute throughout this unit. */
58 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
59 #ifdef TARGET_64BIT
60 #define Has_Stdcall_Convention(E) \
61 (!TARGET_64BIT && Convention (E) == Convention_Stdcall)
62 #define Has_Thiscall_Convention(E) \
63 (!TARGET_64BIT && is_cplusplus_method (E))
64 #else
65 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
66 #define Has_Thiscall_Convention(E) (is_cplusplus_method (E))
67 #endif
68 #else
69 #define Has_Stdcall_Convention(E) 0
70 #define Has_Thiscall_Convention(E) 0
71 #endif
75 /* Stack realignment is necessary for functions with foreign conventions when
76 the ABI doesn't mandate as much as what the compiler assumes - that is, up
77 to PREFERRED_STACK_BOUNDARY.
79 Such realignment can be requested with a dedicated function type attribute
80 on the targets that support it. We define FOREIGN_FORCE_REALIGN_STACK to
81 characterize the situations where the attribute should be set. We rely on
82 compiler configuration settings for 'main' to decide. */
84 #ifdef MAIN_STACK_BOUNDARY
85 #define FOREIGN_FORCE_REALIGN_STACK \
86 (MAIN_STACK_BOUNDARY < PREFERRED_STACK_BOUNDARY)
87 #else
88 #define FOREIGN_FORCE_REALIGN_STACK 0
89 #endif
91 struct incomplete
92 {
94 tree old_type;
95 Entity_Id full_type;
96 };
98 /* These variables are used to defer recursively expanding incomplete types
99 while we are processing a record, an array or a subprogram type. */
103 /* This variable is used to delay expanding From_Limited_With types until the
104 end of the spec. */
108 tree discriminant;
109 tree replacement;
114 /* The type of the variant. */
115 tree type;
117 /* The associated field. */
118 tree field;
120 /* The value of the qualifier. */
121 tree qual;
123 /* The type of the variant after transformation. */
124 tree new_type;
128 /* A map used to cache the result of annotate_value. */
130 {
133 {
135 }
139 {
141 }
143 static int
145 {
147 }
148 };
152 /* A map used to associate a dummy type with a list of subprogram entities. */
154 {
157 };
159 void
161 {
162 }
164 void
166 {
168 }
171 {
174 {
176 }
180 {
182 }
184 static int
186 {
188 }
189 };
242 /* The relevant constituents of a subprogram binding to a GCC builtin. Used
243 to pass around calls performing profile compatibility checks. */
252 \f
253 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
254 entity, return the equivalent GCC tree for that entity (a ..._DECL node)
255 and associate the ..._DECL node with the input GNAT defining identifier.
257 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
258 initial value (in GCC tree form). This is optional for a variable. For
259 a renamed entity, GNU_EXPR gives the object being renamed.
261 DEFINITION is true if this call is intended for a definition. This is used
262 for separate compilation where it is necessary to know whether an external
263 declaration or a definition must be created if the GCC equivalent was not
264 created previously. */
266 tree
268 {
269 /* Contains the kind of the input GNAT node. */
271 /* True if this is a type. */
273 /* True if this is an artificial entity. */
275 /* True if debug info is requested for this entity. */
277 /* True if this entity is to be considered as imported. */
278 const bool imported_p
280 /* For a type, contains the equivalent GNAT node to be used in gigi. */
282 /* Temporary used to walk the GNAT tree. */
283 Entity_Id gnat_temp;
284 /* Contains the GCC DECL node which is equivalent to the input GNAT node.
285 This node will be associated with the GNAT node by calling at the end
286 of the `switch' statement. */
288 /* Contains the GCC type to be used for the GCC node. */
290 /* Contains the GCC size tree to be used for the GCC node. */
292 /* Contains the GCC name to be used for the GCC node. */
293 tree gnu_entity_name;
294 /* True if we have already saved gnu_decl as a GNAT association. */
296 /* True if we incremented defer_incomplete_level. */
298 /* True if we incremented force_global. */
300 /* True if we should check to see if elaborated during processing. */
302 /* True if we made GNU_DECL and its type here. */
304 /* Size and alignment of the GCC node, if meaningful. */
306 /* Contains the list of attributes directly attached to the entity. */
309 /* Since a use of an Itype is a definition, process it as such if it
310 is not in a with'ed unit. */
312 && is_type
316 {
317 /* Ensure that we are in a subprogram mentioned in the Scope chain of
318 this entity, our current scope is global, or we encountered a task
319 or entry (where we can't currently accurately check scoping). */
322 {
325 }
330 {
335 gnat_temp
347 && (current_function_decl
349 {
352 }
353 }
355 /* This abort means the Itype has an incorrect scope, i.e. that its
356 scope does not correspond to the subprogram it is declared in. */
358 }
360 /* If we've already processed this entity, return what we got last time.
361 If we are defining the node, we should not have already processed it.
362 In that case, we will abort below when we try to save a new GCC tree
363 for this object. We also need to handle the case of getting a dummy
364 type when a Full_View exists but be careful so as not to trigger its
365 premature elaboration. */
368 {
377 {
378 gnu_decl
382 }
385 }
387 /* If this is a numeric or enumeral type, or an access type, a nonzero Esize
388 must be specified unless it was specified by the programmer. Exceptions
389 are for access-to-protected-subprogram types and all access subtypes, as
390 another GNAT type is used to lay out the GCC type for them. */
401 /* The RM size must be specified for all discrete and fixed-point types. */
405 /* If we get here, it means we have not yet done anything with this entity.
406 If we are not defining it, it must be a type or an entity that is defined
407 elsewhere or externally, otherwise we should have defined it already. */
409 || type_annotate_only
410 || is_type
417 /* Get the name of the entity and set up the line number and filename of
418 the original definition for use in any decl we make. Make sure we do not
419 inherit another source location. */
425 /* For cases when we are not defining (i.e., we are referencing from
426 another compilation unit) public entities, show we are at global level
427 for the purpose of computing scopes. Don't do this for components or
428 discriminants since the relevant test is whether or not the record is
429 being defined. */
437 /* Handle any attributes directly attached to the entity. */
441 /* Do some common processing for types. */
443 {
444 /* Compute the equivalent type to be used in gigi. */
447 /* Machine_Attributes on types are expected to be propagated to
448 subtypes. The corresponding Gigi_Rep_Items are only attached
449 to the first subtype though, so we handle the propagation here. */
456 /* Compute a default value for the size of an elementary type. */
458 {
468 else
473 }
474 }
477 {
480 {
481 /* The GNAT record where the component was defined. */
484 /* If the entity is a discriminant of an extended tagged type used to
485 rename a discriminant of the parent type, return the latter. */
488 {
489 gnu_decl
494 }
496 /* If the entity is an inherited component (in the case of extended
497 tagged record types), just return the original entity, which must
498 be a FIELD_DECL. Likewise for discriminants. If the entity is a
499 non-girder discriminant (in the case of derived untagged record
500 types), return the stored discriminant it renames. */
503 {
504 gnu_decl
509 }
511 /* Otherwise, if we are not defining this and we have no GCC type
512 for the containing record, make one for it. Then we should
513 have made our own equivalent. */
515 {
516 /* ??? If this is in a record whose scope is a protected
517 type and we have an Original_Record_Component, use it.
518 This is a workaround for major problems in protected type
519 handling. */
523 {
524 gnu_decl
528 }
529 else
530 {
533 }
537 }
539 /* Here we have no GCC type and this is a reference rather than a
540 definition. This should never happen. Most likely the cause is
541 reference before declaration in the GNAT tree for gnat_entity. */
543 }
546 /* Ignore constant definitions already marked with the error node. See
547 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
551 {
554 }
556 /* Ignore deferred constant definitions without address clause since
557 they are processed fully in the front-end. If No_Initialization
558 is set, this is not a deferred constant but a constant whose value
559 is built manually. And constants that are renamings are handled
560 like variables. */
562 && !gnu_expr
566 {
570 }
572 /* If this is a use of a deferred constant without address clause,
573 get its full definition. */
577 {
578 gnu_decl
582 }
584 /* If we have a constant that we are not defining, get the expression it
585 was defined to represent. This is necessary to avoid generating dumb
586 elaboration code in simple cases, but we may throw it away later if it
587 is not a constant. But do not retrieve it if it is an allocator since
588 the designated type might still be dummy at this point. */
594 /* The expression may contain N_Expression_With_Actions nodes and
595 thus object declarations from other units. Discard them. */
596 gnu_expr
599 /* fall through */
605 {
607 /* Always create a variable for volatile objects and variables seen
608 constant but with a Linker_Section pragma. */
609 bool const_flag
622 /* We implement RM 13.3(19) for exported and imported (non-constant)
623 objects by making them volatile. */
624 bool volatile_flag
631 tree gnu_object_size;
633 /* We need to translate the renamed object even though we are only
634 referencing the renaming. But it may contain a call for which
635 we'll generate a temporary to hold the return value and which
636 is part of the definition of the renaming, so discard it. */
638 {
642 else
644 }
646 /* Get the type after elaborating the renamed object. */
650 else
651 {
654 /* If this is a standard exception definition, use the standard
655 exception type. This is necessary to make sure that imported
656 and exported views of exceptions are merged in LTO mode. */
660 }
662 /* For a debug renaming declaration, build a debug-only entity. */
664 {
665 /* Force a non-null value to make sure the symbol is retained. */
669 integer_minus_one_node));
676 }
678 /* If this is a loop variable, its type should be the base type.
679 This is because the code for processing a loop determines whether
680 a normal loop end test can be done by comparing the bounds of the
681 loop against those of the base type, which is presumed to be the
682 size used for computation. But this is not correct when the size
683 of the subtype is smaller than the type. */
687 /* Reject non-renamed objects whose type is an unconstrained array or
688 any object whose type is a dummy type or void. */
693 {
696 force_global--;
698 }
700 /* If an alignment is specified, use it if valid. Note that exceptions
701 are objects but don't have an alignment. We must do this before we
702 validate the size, since the alignment can affect the size. */
704 {
710 /* No point in changing the type if there is an address clause
711 as the final type of the object will be a reference type. */
714 else
715 {
718 gnu_type
722 /* If a padding record was made, declare it now since it will
723 never be declared otherwise. This is necessary to ensure
724 that its subtrees are properly marked. */
728 }
729 }
731 /* If we are defining the object, see if it has a Size and validate it
732 if so. If we are not defining the object and a Size clause applies,
733 simply retrieve the value. We don't want to ignore the clause and
734 it is expected to have been validated already. Then get the new
735 type, if any. */
744 {
745 gnu_type
751 }
753 /* If this object has self-referential size, it must be a record with
754 a default discriminant. We are supposed to allocate an object of
755 the maximum size in this case, unless it is a constant with an
756 initializing expression, in which case we can get the size from
757 that. Note that the resulting size may still be a variable, so
758 this may end up with an indirect allocation. */
761 {
763 {
766 {
767 /* If the initializing expression is itself a constant,
768 despite having a nominal type with self-referential
769 size, we can get the size directly from it. */
771 && TYPE_IS_PADDING_P
775 || DECL_READONLY_ONCE_ELAB
778 else
779 gnu_size
781 }
782 else
784 }
785 /* We may have no GNU_EXPR because No_Initialization is
786 set even though there's an Expression. */
791 gnu_size
793 (Etype
795 else
796 {
799 }
801 /* If the size isn't constant and we are at global level, call
802 elaborate_expression_1 to make a variable for it rather than
803 calculating it each time. */
807 }
809 /* If the size is zero byte, make it one byte since some linkers have
810 troubles with zero-sized objects. If the object will have a
811 template, that will make it nonzero so don't bother. Also avoid
812 doing that for an object renaming or an object with an address
813 clause, as we would lose useful information on the view size
814 (e.g. for null array slices) and we are not allocating the object
815 here anyway. */
827 /* If this is an object with no specified size and alignment, and
828 if either it is atomic or we are not optimizing alignment for
829 space and it is composite and not an exception, an Out parameter
830 or a reference to another object, and the size of its type is a
831 constant, set the alignment to the smallest one which is not
832 smaller than the size, with an appropriate cap. */
841 && !imported_p
845 {
848 /* No point in promoting the alignment if this doesn't prevent
849 BLKmode access to the object, in particular block copy, as
850 this will for example disable the NRV optimization for it.
851 No point in jumping through all the hoops needed in order
852 to support BIGGEST_ALIGNMENT if we don't really have to.
853 So we cap to the smallest alignment that corresponds to
854 a known efficient memory access pattern of the target. */
856 {
859 }
860 else
861 {
864 }
871 else
874 /* But make sure not to under-align the object. */
878 /* And honor the minimum valid atomic alignment, if any. */
879 #ifdef MINIMUM_ATOMIC_ALIGNMENT
882 #endif
883 }
885 /* If the object is set to have atomic components, find the component
886 type and validate it.
888 ??? Note that we ignore Has_Volatile_Components on objects; it's
889 not at all clear what to do in that case. */
891 {
900 }
902 /* If this is an aliased object with an unconstrained array nominal
903 subtype, make a type that includes the template. We will either
904 allocate or create a variable of that type, see below. */
908 {
910 gnu_type
912 gnu_type,
915 debug_info_p);
916 }
918 /* ??? If this is an object of CW type initialized to a value, try to
919 ensure that the object is sufficient aligned for this value, but
920 without pessimizing the allocation. This is a kludge necessary
921 because we don't support dynamic alignment. */
928 #ifdef MINIMUM_ATOMIC_ALIGNMENT
929 /* If the size is a constant and no alignment is specified, force
930 the alignment to be the minimum valid atomic alignment. The
931 restriction on constant size avoids problems with variable-size
932 temporaries; if the size is variable, there's no issue with
933 atomic access. Also don't do this for a constant, since it isn't
934 necessary and can interfere with constant replacement. Finally,
935 do not do it for Out parameters since that creates an
936 size inconsistency with In parameters. */
946 #endif
948 /* Make a new type with the desired size and alignment, if needed.
949 But do not take into account alignment promotions to compute the
950 size of the object. */
953 {
959 /* If a padding record was made, declare it now since it will
960 never be declared otherwise. This is necessary to ensure
961 that its subtrees are properly marked. */
965 }
967 /* Now check if the type of the object allows atomic access. */
971 /* If this is a renaming, avoid as much as possible to create a new
972 object. However, in some cases, creating it is required because
973 renaming can be applied to objects that are not names in Ada.
974 This processing needs to be applied to the raw expression so as
975 to make it more likely to rename the underlying object. */
977 {
978 /* If the renamed object had padding, strip off the reference to
979 the inner object and reset our type. */
982 /* Strip useless conversions around the object. */
984 {
987 }
989 /* Or else, if the renamed object has an unconstrained type with
990 default discriminant, use the padded type. */
994 /* Case 1: if this is a constant renaming stemming from a function
995 call, treat it as a normal object whose initial value is what
996 is being renamed. RM 3.3 says that the result of evaluating a
997 function call is a constant object. Therefore, it can be the
998 inner object of a constant renaming and the renaming must be
999 fully instantiated, i.e. it cannot be a reference to (part of)
1000 an existing object. And treat other rvalues (addresses, null
1001 expressions, constructors and literals) the same way. */
1005 /* Expand_Dispatching_Call can prepend a comparison of the tags
1006 before the call to "=". */
1017 /* We need to detect the case where a temporary is created to
1018 hold the return value, since we cannot safely rename it at
1019 top level as it lives only in the elaboration routine. */
1022 /* We also need to detect the case where the front-end creates
1023 a dangling 'reference to a function call at top level and
1024 substitutes it in the renaming, for example:
1026 q__b : boolean renames r__f.e (1);
1028 can be rewritten into:
1030 q__R1s : constant q__A2s := r__f'reference;
1031 [...]
1032 q__b : boolean renames q__R1s.all.e (1);
1034 We cannot safely rename the rewritten expression since the
1035 underlying object lives only in the elaboration routine. */
1037 && (inner
1041 ;
1043 /* Case 2: if the renaming entity need not be materialized, use
1044 the elaborated renamed expression for the renaming. But this
1045 means that the caller is responsible for evaluating the address
1046 of the renaming in the correct place for the definition case to
1047 instantiate the SAVE_EXPRs. */
1049 {
1052 gnu_decl
1056 /* We cannot evaluate the first arm of a COMPOUND_EXPR in the
1057 correct place for this case. */
1060 /* No DECL_EXPR will be created so the expression needs to be
1061 marked manually because it will likely be shared. */
1065 /* This assertion will fail if the renamed object isn't aligned
1066 enough as to make it possible to honor the alignment set on
1067 the renaming. */
1069 {
1074 }
1076 /* The expression might not be a DECL so save it manually. */
1081 }
1083 /* Case 3: otherwise, make a constant pointer to the object we
1084 are renaming and attach the object to the pointer after it is
1085 elaborated. The object will be referenced directly instead
1086 of indirectly via the pointer to avoid aliasing problems with
1087 non-addressable entities. The pointer is called a "renaming"
1088 pointer in this case. Note that we also need to preserve the
1089 volatility of the renamed object through the indirection. */
1090 else
1091 {
1095 gnu_type
1104 renamed_obj
1108 /* The expression needs to be marked manually because it will
1109 likely be shared, even for a definition since the ADDR_EXPR
1110 built below can cause the first few nodes to be folded. */
1117 else
1118 {
1119 gnu_expr
1122 gnu_expr
1124 gnu_expr);
1125 }
1126 }
1127 }
1129 /* If we are defining an aliased object whose nominal subtype is
1130 unconstrained, the object is a record that contains both the
1131 template and the object. If there is an initializer, it will
1132 have already been converted to the right type, but we need to
1133 create the template if there is no initializer. */
1135 && !gnu_expr
1138 /* Beware that padding might have been introduced above. */
1141 == RECORD_TYPE
1142 && TYPE_CONTAINS_TEMPLATE_P
1144 {
1145 tree template_field
1153 NULL_TREE);
1156 }
1158 /* Convert the expression to the type of the object if need be. */
1162 /* If this is a pointer that doesn't have an initializing expression,
1163 initialize it to NULL, unless the object is declared imported as
1164 per RM B.1(24). */
1167 && !gnu_expr
1171 /* If we are defining the object and it has an Address clause, we must
1172 either get the address expression from the saved GCC tree for the
1173 object if it has a Freeze node, or elaborate the address expression
1174 here since the front-end has guaranteed that the elaboration has no
1175 effects in this case. */
1177 {
1180 tree gnu_address
1186 /* Convert the type of the object to a reference type that can
1187 alias everything as per RM 13.3(19). */
1190 gnu_type
1194 const_flag
1200 /* If this is an aliased object with an unconstrained array nominal
1201 subtype, then it can overlay only another aliased object with an
1202 unconstrained array nominal subtype and compatible template. */
1206 {
1210 /* This is the pattern built for a regular object. */
1214 /* This is the pattern built for an overaligned object. */
1217 == PLUS_EXPR
1220 gnu_address
1224 else
1225 {
1228 gnat_entity);
1231 }
1232 }
1234 /* If we don't have an initializing expression for the underlying
1235 variable, the initializing expression for the pointer is the
1236 specified address. Otherwise, we have to make a COMPOUND_EXPR
1237 to assign both the address and the initial value. */
1240 else
1241 gnu_expr
1245 NULL_TREE,
1246 gnu_address),
1247 gnu_expr),
1248 gnu_address);
1249 }
1251 /* If it has an address clause and we are not defining it, mark it
1252 as an indirect object. Likewise for Stdcall objects that are
1253 imported. */
1256 {
1257 /* Convert the type of the object to a reference type that can
1258 alias everything as per RM 13.3(19). */
1261 gnu_type
1268 /* No point in taking the address of an initializing expression
1269 that isn't going to be used. */
1272 /* If it has an address clause whose value is known at compile
1273 time, make the object a CONST_DECL. This will avoid a
1274 useless dereference. */
1276 {
1277 Node_Id gnat_address
1281 {
1284 }
1285 }
1286 }
1288 /* If we are at top level and this object is of variable size,
1289 make the actual type a hidden pointer to the real type and
1290 make the initializer be a memory allocation and initialization.
1291 Likewise for objects we aren't defining (presumed to be
1292 external references from other packages), but there we do
1293 not set up an initialization.
1295 If the object's size overflows, make an allocator too, so that
1296 Storage_Error gets raised. Note that we will never free
1297 such memory, so we presume it never will get allocated. */
1300 || !definition
1302 || (gnu_size
1304 size_binop
1306 bitsize_unit_node)),
1308 || !definition
1310 {
1319 /* In case this was a aliased object whose nominal subtype is
1320 unconstrained, the pointer above will be a thin pointer and
1321 build_allocator will automatically make the template.
1323 If we have a template initializer only (that we made above),
1324 pretend there is none and rely on what build_allocator creates
1325 again anyway. Otherwise (if we have a full initializer), get
1326 the data part and feed that to build_allocator.
1328 If we are elaborating a mutable object, tell build_allocator to
1329 ignore a possibly simpler size from the initializer, if any, as
1330 we must allocate the maximum possible size in this case. */
1332 {
1337 {
1338 gnu_alloc_type
1344 else
1345 gnu_expr
1346 = build_component_ref
1350 }
1355 gnat_entity);
1357 gnu_expr
1360 }
1361 else
1363 }
1365 /* If this object would go into the stack and has an alignment larger
1366 than the largest stack alignment the back-end can honor, resort to
1367 a variable of "aligning type". */
1370 && !imported_p
1371 && !static_flag
1373 {
1374 /* Create the new variable. No need for extra room before the
1375 aligned field as this is in automatic storage. */
1376 tree gnu_new_type
1380 tree gnu_new_var
1386 /* Initialize the aligned field if we have an initializer. */
1388 add_stmt_with_node
1390 build_component_ref
1393 gnu_expr),
1394 gnat_entity);
1396 /* And setup this entity as a reference to the aligned field. */
1398 gnu_expr
1399 = build_unary_op
1409 }
1411 /* If this is an aliased object with an unconstrained array nominal
1412 subtype, we make its type a thin reference, i.e. the reference
1413 counterpart of a thin pointer, so it points to the array part.
1414 This is aimed to make it easier for the debugger to decode the
1415 object. Note that we have to do it this late because of the
1416 couple of allocation adjustments that might be made above. */
1420 {
1421 /* In case the object with the template has already been allocated
1422 just above, we have nothing to do here. */
1424 {
1425 /* This variable is a GNAT encoding used by Workbench: let it
1426 go through the debugging information but mark it as
1427 artificial: users are not interested in it. */
1428 tree gnu_unc_var
1443 }
1446 gnu_type
1448 }
1450 /* Convert the expression to the type of the object if need be. */
1454 /* If this name is external or a name was specified, use it, but don't
1455 use the Interface_Name with an address clause (see cd30005). */
1461 /* If this is an aggregate constant initialized to a constant, force it
1462 to be statically allocated. This saves an initialization copy. */
1464 && const_flag
1473 /* Deal with a pragma Linker_Section on a constant or variable. */
1479 /* Now create the variable or the constant and set various flags. */
1480 gnu_decl
1490 /* If we are defining an Out parameter and optimization isn't enabled,
1491 create a fake PARM_DECL for debugging purposes and make it point to
1492 the VAR_DECL. Suppress debug info for the latter but make sure it
1493 will live in memory so that it can be accessed from within the
1494 debugger through the PARM_DECL. */
1496 && definition
1497 && debug_info_p
1498 && !optimize
1500 {
1507 }
1509 /* If this is a loop parameter, set the corresponding flag. */
1513 /* If this is a renaming pointer, attach the renamed object to it. */
1517 /* If this is a constant and we are defining it or it generates a real
1518 symbol at the object level and we are referencing it, we may want
1519 or need to have a true variable to represent it:
1520 - if optimization isn't enabled, for debugging purposes,
1521 - if the constant is public and not overlaid on something else,
1522 - if its address is taken,
1523 - if either itself or its type is aliased. */
1532 {
1533 tree gnu_corr_var
1541 }
1543 /* If this is a constant, even if we don't need a true variable, we
1544 may need to avoid returning the initializer in every case. That
1545 can happen for the address of a (constant) constructor because,
1546 upon dereferencing it, the constructor will be reinjected in the
1547 tree, which may not be valid in every case; see lvalue_required_p
1548 for more details. */
1552 /* If this object is declared in a block that contains a block with an
1553 exception handler, and we aren't using the GCC exception mechanism,
1554 we must force this variable in memory in order to avoid an invalid
1555 optimization. */
1560 /* If this is a local variable with non-BLKmode and aggregate type,
1561 and optimization isn't enabled, then force it in memory so that
1562 a register won't be allocated to it with possible subparts left
1563 uninitialized and reaching the register allocator. */
1573 /* If we are defining an object with variable size or an object with
1574 fixed size that will be dynamically allocated, and we are using the
1575 front-end setjmp/longjmp exception mechanism, update the setjmp
1576 buffer. */
1589 gnat_entity);
1591 /* Back-annotate Esize and Alignment of the object if not already
1592 known. Note that we pick the values of the type, not those of
1593 the object, to shield ourselves from low-level platform-dependent
1594 adjustments like alignment promotion. This is both consistent with
1595 all the treatment above, where alignment and size are set on the
1596 type of the object and not on the object directly, and makes it
1597 possible to support all confirming representation clauses. */
1599 used_by_ref);
1600 }
1604 /* Return a TYPE_DECL for "void" that we previously made. */
1609 /* A special case: for the types Character and Wide_Character in
1610 Standard, we do not list all the literals. So if the literals
1611 are not specified, make this an integer type. */
1613 {
1616 else
1620 /* Set TYPE_STRING_FLAG for Character and Wide_Character types.
1621 This is needed by the DWARF-2 back-end to distinguish between
1622 unsigned integer types and character types. */
1625 /* This flag is needed by the call just below. */
1629 }
1630 else
1631 {
1632 /* We have a list of enumeral constants in First_Literal. We make a
1633 CONST_DECL for each one and build into GNU_LITERAL_LIST the list
1634 to be placed into TYPE_FIELDS. Each node is itself a TREE_LIST
1635 whose TREE_VALUE is the literal name and whose TREE_PURPOSE is the
1636 value of the literal. But when we have a regular boolean type, we
1637 simplify this a little by using a BOOLEAN_TYPE. */
1642 Entity_Id gnat_literal;
1655 {
1656 tree gnu_value
1658 /* Do not generate debug info for individual enumerators. */
1659 tree gnu_literal
1665 gnu_list
1667 }
1672 /* Note that the bounds are updated at the end of this function
1673 to avoid an infinite recursion since they refer to the type. */
1675 }
1679 /* For integer types, just make a signed type the appropriate number
1680 of bits. */
1686 {
1687 /* Small_Value is the scale factor. */
1693 /* Try to decode the scale factor and to save it for the fixed-point
1694 types debug hook. */
1696 /* There are various ways to describe the scale factor, however there
1697 are cases where back-end internals cannot hold it. In such cases,
1698 we output invalid scale factor for such cases (i.e. the 0/0
1699 rational constant) but we expect GNAT to output GNAT encodings,
1700 then. Thus, keep this in sync with
1701 Exp_Dbug.Is_Handled_Scale_Factor. */
1703 /* When encoded as 1/2**N or 1/10**N, describe the scale factor as a
1704 binary or decimal scale: it is easier to read for humans. */
1708 {
1709 /* Given RM restrictions on 'Small values, we assume here that
1710 the denominator fits in an int. */
1713 const tree exponent
1716 scale_factor
1718 integer_one_node,
1721 }
1723 /* Default to arbitrary scale factors descriptions. */
1724 else
1725 {
1730 {
1731 const tree gnu_num
1734 const tree gnu_den
1739 }
1740 else
1741 /* If compiler internals cannot represent arbitrary scale
1742 factors, output an invalid scale factor so that debugger
1743 don't try to handle them but so that we still have a type
1744 in the output. Note that GNAT */
1746 }
1750 }
1754 {
1755 /* For modular types, make the unsigned type of the proper number
1756 of bits and then set up the modulus, if required. */
1759 /* Packed Array Impl. Types are supposed to be subtypes only. */
1764 /* Get the modulus in this type. If it overflows, assume it is because
1765 it is equal to 2**Esize. Note that there is no overflow checking
1766 done on unsigned type, so we detect the overflow by looking for
1767 a modulus of zero, which is otherwise invalid. */
1771 {
1776 }
1778 /* If the upper bound is not maximal, make an extra subtype. */
1781 {
1788 }
1789 }
1798 /* For integral subtypes, we make a new INTEGER_TYPE. Note that we do
1799 not want to call create_range_type since we would like each subtype
1800 node to be distinct. ??? Historically this was in preparation for
1801 when memory aliasing is implemented, but that's obsolete now given
1802 the call to relate_alias_sets below.
1804 The TREE_TYPE field of the INTEGER_TYPE points to the base type;
1805 this fact is used by the arithmetic conversion functions.
1807 We elaborate the Ancestor_Subtype if it is not in the current unit
1808 and one of our bounds is non-static. We do this to ensure consistent
1809 naming in the case where several subtypes share the same bounds, by
1810 elaborating the first such subtype first, thus using its name. */
1819 /* Set the precision to the Esize except for bit-packed arrays. */
1824 /* First subtypes of Character are treated as Character; otherwise
1825 this should be an unsigned type if the base type is unsigned or
1826 if the lower bound is constant and non-negative or if the type
1827 is biased. However, even if the lower bound is constant and
1828 non-negative, we use a signed type for a subtype with the same
1829 size as its signed base type, because this eliminates useless
1830 conversions to it and gives more leeway to the optimizer; but
1831 this means that we will need to explicitly test for this case
1832 when we change the representation based on the RM size. */
1844 else
1848 SET_TYPE_RM_MIN_VALUE
1851 debug_info_p));
1853 SET_TYPE_RM_MAX_VALUE
1856 debug_info_p));
1861 /* Set TYPE_STRING_FLAG for Character and Wide_Character subtypes. */
1864 /* Inherit our alias set from what we're a subtype of. Subtypes
1865 are not different types and a pointer can designate any instance
1866 within a subtype hierarchy. */
1869 /* One of the above calls might have caused us to be elaborated,
1870 so don't blow up if so. */
1872 {
1875 }
1877 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
1881 /* For a packed array, make the original array type a parallel/debug
1882 type. */
1886 discrete_type:
1888 /* We have to handle clauses that under-align the type specially. */
1891 && Present
1894 {
1898 }
1900 /* If the type we are dealing with represents a bit-packed array,
1901 we need to have the bits left justified on big-endian targets
1902 and right justified on little-endian targets. We also need to
1903 ensure that when the value is read (e.g. for comparison of two
1904 such values), we only get the good bits, since the unused bits
1905 are uninitialized. Both goals are accomplished by wrapping up
1906 the modular type in an enclosing record type. */
1909 {
1912 /* Set the RM size before wrapping up the original type. */
1917 /* Strip the ___XP suffix for standard DWARF. */
1921 /* Create a stripped-down declaration, mainly for debugging. */
1923 gnat_entity);
1925 /* Now save it and build the enclosing record type. */
1935 /* Propagate the alignment of the modular type to the record type,
1936 unless there is an alignment clause that under-aligns the type.
1937 This means that bit-packed arrays are given "ceil" alignment for
1938 their size by default, which may seem counter-intuitive but makes
1939 it possible to overlay them on modular types easily. */
1943 /* Propagate the reverse storage order flag to the record type so
1944 that the required byte swapping is performed when retrieving the
1945 enclosed modular value. */
1951 /* Don't declare the field as addressable since we won't be taking
1952 its address and this would prevent create_field_decl from making
1953 a bitfield. */
1954 gnu_field
1958 /* We will output additional debug info manually below. */
1964 {
1965 /* Make the original array type a parallel/debug type. */
1968 /* Since GNU_TYPE is a padding type around the packed array
1969 implementation type, the padded type is its debug type. */
1972 }
1973 }
1975 /* If the type we are dealing with has got a smaller alignment than the
1976 natural one, we need to wrap it up in a record type and misalign the
1977 latter; we reuse the padding machinery for this purpose. */
1979 {
1982 /* Set the RM size before wrapping the type. */
1985 gnu_type
1991 }
1996 /* The type of the Low and High bounds can be our type if this is
1997 a type from Standard, so set them at the end of the function. */
2004 /* See the E_Signed_Integer_Subtype case for the rationale. */
2021 SET_TYPE_RM_MIN_VALUE
2024 debug_info_p));
2026 SET_TYPE_RM_MAX_VALUE
2029 debug_info_p));
2031 /* Inherit our alias set from what we're a subtype of, as for
2032 integer subtypes. */
2035 /* One of the above calls might have caused us to be elaborated,
2036 so don't blow up if so. */
2040 /* Array Types and Subtypes
2042 Unconstrained array types are represented by E_Array_Type and
2043 constrained array types are represented by E_Array_Subtype. There
2044 are no actual objects of an unconstrained array type; all we have
2045 are pointers to that type.
2047 The following fields are defined on array types and subtypes:
2049 Component_Type Component type of the array.
2050 Number_Dimensions Number of dimensions (an int).
2051 First_Index Type of first index. */
2054 {
2055 const bool convention_fortran_p
2058 tree gnu_template_type;
2059 tree gnu_ptr_template;
2066 tree comp_type;
2068 /* Create the type for the component now, as it simplifies breaking
2069 type reference loops. */
2070 comp_type
2073 {
2074 /* As a side effect, the type may have been translated. */
2077 }
2079 /* We complete an existing dummy fat pointer type in place. This both
2080 avoids further complex adjustments in update_pointer_to and yields
2081 better debugging information in DWARF by leveraging the support for
2082 incomplete declarations of "tagged" types in the DWARF back-end. */
2085 {
2088 /* Save the contents of the dummy type for update_pointer_to. */
2090 gnu_ptr_template =
2093 }
2094 else
2095 {
2099 }
2101 /* Make a node for the array. If we are not defining the array
2102 suppress expanding incomplete types. */
2106 {
2107 defer_incomplete_level++;
2109 }
2111 /* Build the fat pointer type. Use a "void *" object instead of
2112 a pointer to the array type since we don't have the array type
2113 yet (it will reference the fat pointer via the bounds). */
2114 tem
2122 {
2123 /* We are going to lay it out again so reset the alias set. */
2129 {
2132 }
2133 }
2134 else
2135 {
2138 }
2140 /* Build a reference to the template from a PLACEHOLDER_EXPR that
2141 is the fat pointer. This will be used to access the individual
2142 fields once we build them. */
2146 gnu_template_reference
2151 /* Now create the GCC type for each index and add the fields for that
2152 index to the template. */
2158 {
2161 tree gnu_index_base_type
2166 /* Make the FIELD_DECLs for the low and high bounds of this
2167 type and then make extractions of these fields from the
2168 template. */
2171 gnu_index_base_type,
2179 gnu_index_base_type,
2187 /* We can't use build_component_ref here since the template type
2188 isn't complete yet. */
2191 NULL_TREE);
2194 NULL_TREE);
2200 /* Compute the size of this dimension. See the E_Array_Subtype
2201 case below for the rationale. */
2202 gnu_high
2206 gnu_max,
2209 /* Make a range type with the new range in the Ada base type.
2210 Then make an index type with the size range in sizetype. */
2214 gnu_orig_min,
2215 gnu_orig_max),
2216 gnat_entity);
2218 /* Update the maximum size of the array in elements. */
2220 {
2221 tree gnu_min
2223 tree gnu_max
2225 tree gnu_this_max
2232 else
2233 gnu_max_size
2235 }
2239 }
2241 /* Install all the fields into the template. */
2246 gnu_template_fields
2249 debug_info_p);
2252 /* If Component_Size is not already specified, annotate it with the
2253 size of the component. */
2258 /* Compute the maximum size of the array in units and bits. */
2260 {
2266 }
2267 else
2270 /* Now build the array type. */
2273 {
2281 }
2283 /* If an alignment is specified, use it if valid. But ignore it
2284 for the original type of packed array types. If the alignment
2285 was requested with an explicit alignment clause, state so. */
2288 {
2291 gnat_entity,
2295 }
2297 /* Tag top-level ARRAY_TYPE nodes for packed arrays and their
2298 implementation types as such so that the debug information back-end
2299 can output the appropriate description for them. */
2307 /* Adjust the type of the pointer-to-array field of the fat pointer
2308 and record the aliasing relationships if necessary. */
2313 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2314 corresponding fat pointer. */
2321 /* If the maximum size doesn't overflow, use it. */
2327 {
2332 }
2337 /* If told to generate GNAT encodings for them (GDB rely on them at the
2338 moment): give the fat pointer type a name. If this is a packed
2339 array, tell the debugger how to interpret the underlying bits. */
2342 else
2344 tree xup_name
2349 gnat_entity);
2351 /* Create the type to be designated by thin pointers: a record type for
2352 the array and its template. We used to shift the fields to have the
2353 template at a negative offset, but this was somewhat of a kludge; we
2354 now shift thin pointer values explicitly but only those which have a
2355 TYPE_UNCONSTRAINED_ARRAY attached to the designated RECORD_TYPE.
2356 Note that GDB can handle standard DWARF information for them, so we
2357 don't have to name them as a GNAT encoding, except if specifically
2358 asked to. */
2359 tree xut_name
2364 debug_info_p);
2368 }
2373 /* This is the actual data type for array variables. Multidimensional
2374 arrays are implemented as arrays of arrays. Note that arrays which
2375 have sparse enumeration subtypes as index components create sparse
2376 arrays, which is obviously space inefficient but so much easier to
2377 code for now.
2379 Also note that the subtype never refers to the unconstrained array
2380 type, which is somewhat at variance with Ada semantics.
2382 First check to see if this is simply a renaming of the array type.
2383 If so, the result is the array type. */
2387 ;
2388 else
2389 {
2391 const bool convention_fortran_p
2400 /* First create the GCC type for each index and find out whether
2401 special types are needed for debugging information. */
2404 gnat_base_index
2410 {
2412 tree gnu_index_base_type
2414 tree gnu_orig_min
2417 tree gnu_orig_max
2422 tree gnu_base_index_type
2424 tree gnu_base_index_base_type
2426 tree gnu_base_orig_min
2429 tree gnu_base_orig_max
2432 tree gnu_high;
2434 /* See if the base array type is already flat. If it is, we
2435 are probably compiling an ACATS test but it will cause the
2436 code below to malfunction if we don't handle it specially. */
2440 {
2444 }
2446 /* Similarly, if one of the values overflows in sizetype and the
2447 range is null, use 1..0 for the sizetype bounds. */
2452 {
2456 }
2458 /* If the minimum and maximum values both overflow in sizetype,
2459 but the difference in the original type does not overflow in
2460 sizetype, ignore the overflow indication. */
2464 && !TREE_OVERFLOW
2467 gnu_orig_max,
2468 gnu_orig_min))))
2469 {
2473 }
2475 /* Compute the size of this dimension in the general case. We
2476 need to provide GCC with an upper bound to use but have to
2477 deal with the "superflat" case. There are three ways to do
2478 this. If we can prove that the array can never be superflat,
2479 we can just use the high bound of the index type. */
2482 /* Bit-Packed Array Impl. Types are never superflat. */
2484 && Is_Bit_Packed_Array
2488 /* Otherwise, if the high bound is constant but the low bound is
2489 not, we use the expression (hb >= lb) ? lb : hb + 1 for the
2490 lower bound. Note that the comparison must be done in the
2491 original type to avoid any overflow during the conversion. */
2494 {
2496 gnu_min
2499 boolean_type_node,
2500 gnu_orig_max,
2501 gnu_orig_min),
2502 gnu_min,
2504 size_one_node));
2505 }
2507 /* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
2508 in all the other cases. Note that, here as well as above,
2509 the condition used in the comparison must be equivalent to
2510 the condition (length != 0). This is relied upon in order
2511 to optimize array comparisons in compare_arrays. Moreover
2512 we use int_const_binop for the shift by 1 if the bound is
2513 constant to avoid any unwanted overflow. */
2514 else
2515 gnu_high
2518 boolean_type_node,
2519 gnu_orig_max,
2520 gnu_orig_min),
2521 gnu_max,
2524 size_one_node)
2526 size_one_node));
2528 /* Reuse the index type for the range type. Then make an index
2529 type with the size range in sizetype. */
2532 gnat_entity);
2534 /* Update the maximum size of the array in elements. Here we
2535 see if any constraint on the index type of the base type
2536 can be used in the case of self-referential bound on the
2537 index type of the subtype. We look for a non-"infinite"
2538 and non-self-referential bound from any type involved and
2539 handle each bound separately. */
2541 {
2544 tree gnu_base_base_min
2547 tree gnu_base_base_max
2568 else
2569 {
2570 tree gnu_this_max;
2572 /* Use int_const_binop if the bounds are constant to
2573 avoid any unwanted overflow. */
2576 gnu_this_max
2579 gnu_base_max,
2580 gnu_base_min));
2581 else
2582 gnu_this_max
2585 gnu_base_max,
2586 gnu_base_min));
2588 gnu_max_size
2590 }
2591 }
2593 /* We need special types for debugging information to point to
2594 the index types if they have variable bounds, are not integer
2595 types, are biased or are wider than sizetype. These are GNAT
2596 encodings, so we have to include them only when all encodings
2597 are requested. */
2607 }
2609 /* Then flatten: create the array of arrays. For an array type
2610 used to implement a packed array, get the component type from
2611 the original array type since the representation clauses that
2612 can affect it are on the latter. */
2615 {
2620 /* One of the above calls might have caused us to be elaborated,
2621 so don't blow up if so. */
2623 {
2626 }
2627 }
2628 else
2629 {
2631 debug_info_p);
2633 /* One of the above calls might have caused us to be elaborated,
2634 so don't blow up if so. */
2636 {
2639 }
2640 }
2642 /* Compute the maximum size of the array in units and bits. */
2644 {
2650 }
2651 else
2654 /* Now build the array type. */
2656 {
2665 }
2667 /* Strip the ___XP suffix for standard DWARF. */
2670 {
2671 Entity_Id gnat_original_array_type
2674 gnu_entity_name
2676 }
2678 /* Attach the TYPE_STUB_DECL in case we have a parallel type. */
2682 /* If this is a multi-dimensional array and we are at global level,
2683 we need to make a variable corresponding to the stride of the
2684 inner dimensions. */
2686 {
2687 tree gnu_arr_type;
2692 {
2702 /* ??? For now, store the size as a multiple of the
2703 alignment of the element type in bytes so that we
2704 can see the alignment from the tree. */
2712 /* ??? create_type_decl is not invoked on the inner types so
2713 the MULT_EXPR node built above will never be marked. */
2715 }
2716 }
2718 /* If we need to write out a record type giving the names of the
2719 bounds for debugging purposes, do it now and make the record
2720 type a parallel type. This is not needed for a packed array
2721 since the bounds are conveyed by the original array type. */
2723 && debug_info_p
2725 {
2728 tree gnu_field;
2734 {
2738 /* Make sure to reference the types themselves, and not just
2739 their names, as the debugger may fall back on them. */
2745 }
2749 }
2751 /* If this is a packed array type, make the original array type a
2752 parallel/debug type. Otherwise, if such GNAT encodings are
2753 required, do it for the base array type if it isn't artificial to
2754 make sure it is kept in the debug info. */
2756 {
2759 gnat_entity);
2760 else
2761 {
2762 tree gnu_base_decl
2769 }
2770 }
2776 /* Tag top-level ARRAY_TYPE nodes for packed arrays and their
2777 implementation types as such so that the debug information back-end
2778 can output the appropriate description for them. */
2783 /* If the size is self-referential and the maximum size doesn't
2784 overflow, use it. */
2786 && gnu_max_size
2791 {
2797 }
2799 /* Set our alias set to that of our base type. This gives all
2800 array subtypes the same alias set. */
2803 /* If this is a packed type, make this type the same as the packed
2804 array type, but do some adjusting in the type first. */
2806 {
2807 Entity_Id gnat_index;
2808 tree gnu_inner;
2810 /* First finish the type we had been making so that we output
2811 debugging information for it. */
2814 {
2815 const int quals
2816 = TYPE_QUAL_VOLATILE
2819 }
2820 /* Make it artificial only if the base type was artificial too.
2821 That's sort of "morally" true and will make it possible for
2822 the debugger to look it up by name in DWARF, which is needed
2823 in order to decode the packed array type. */
2824 gnu_decl
2828 gnat_entity);
2830 /* Save it as our equivalent in case the call below elaborates
2831 this type again. */
2834 gnu_decl
2849 /* We need to attach the index type to the type we just made so
2850 that the actual bounds can later be put into a template. */
2855 {
2857 {
2858 /* The TYPE_ACTUAL_BOUNDS field is overloaded with the
2859 TYPE_MODULUS for modular types so we make an extra
2860 subtype if necessary. */
2862 {
2863 tree gnu_subtype
2872 }
2876 /* Check for other cases of overloading. */
2878 }
2883 SET_TYPE_ACTUAL_BOUNDS
2890 SET_TYPE_ACTUAL_BOUNDS
2896 }
2897 }
2898 }
2902 /* Create the type for a string literal. */
2903 {
2904 Entity_Id gnat_full_type
2909 tree gnu_string_array_type
2911 tree gnu_string_index_type
2914 tree gnu_lower_bound
2917 tree gnu_length
2919 gnu_string_index_type);
2920 tree gnu_upper_bound
2922 gnu_lower_bound,
2925 integer_one_node)));
2926 tree gnu_index_type
2930 gnu_lower_bound,
2931 gnu_upper_bound),
2932 gnat_entity);
2934 gnu_type
2937 gnu_index_type);
2941 }
2944 /* Record Types and Subtypes
2946 The following fields are defined on record types:
2948 Has_Discriminants True if the record has discriminants
2949 First_Discriminant Points to head of list of discriminants
2950 First_Entity Points to head of list of fields
2951 Is_Tagged_Type True if the record is tagged
2953 Implementation of Ada records and discriminated records:
2955 A record type definition is transformed into the equivalent of a C
2956 struct definition. The fields that are the discriminants which are
2957 found in the Full_Type_Declaration node and the elements of the
2958 Component_List found in the Record_Type_Definition node. The
2959 Component_List can be a recursive structure since each Variant of
2960 the Variant_Part of the Component_List has a Component_List.
2962 Processing of a record type definition comprises starting the list of
2963 field declarations here from the discriminants and the calling the
2964 function components_to_record to add the rest of the fields from the
2965 component list and return the gnu type node. The function
2966 components_to_record will call itself recursively as it traverses
2967 the tree. */
2971 {
2972 gnu_type
2973 = build_complex_type
2974 (get_unpadded_type
2977 (Component_List
2978 (Type_Definition
2982 }
2984 {
2987 Node_Id gnat_constr;
2988 Entity_Id gnat_field;
2990 tree gnu_get_parent;
2991 /* Set PACKED in keeping with gnat_to_gnu_field. */
2992 const int packed
3001 const bool is_extension
3007 /* See if all fields have a rep clause. Stop when we find one
3008 that doesn't. */
3016 {
3019 }
3021 /* If this is a record extension, go a level further to find the
3022 record definition. Also, verify we have a Parent_Subtype. */
3024 {
3031 }
3033 /* Make a node for the record. If we are not defining the record,
3034 suppress expanding incomplete types. */
3043 {
3044 defer_incomplete_level++;
3046 }
3048 /* If both a size and rep clause were specified, put the size on
3049 the record type now so that it can get the proper layout. */
3054 /* Always set the alignment on the record type here so that it can
3055 get the proper layout. */
3060 else
3061 {
3064 /* If a type needs strict alignment, the minimum size will be the
3065 type size instead of the RM size (see validate_size). Cap the
3066 alignment lest it causes this type size to become too large. */
3068 {
3073 }
3074 }
3076 /* If we have a Parent_Subtype, make a field for the parent. If
3077 this record has rep clauses, force the position to zero. */
3079 {
3082 tree gnu_parent;
3084 /* A major complexity here is that the parent subtype will
3085 reference our discriminants in its Stored_Constraint list.
3086 But those must reference the parent component of this record
3087 which is precisely of the parent subtype we have not built yet!
3088 To break the circle we first build a dummy COMPONENT_REF which
3089 represents the "get to the parent" operation and initialize
3090 each of those discriminants to a COMPONENT_REF of the above
3091 dummy parent referencing the corresponding discriminant of the
3092 base type of the parent subtype. */
3097 gnu_dummy_parent_type),
3098 NULL_TREE);
3105 {
3106 tree gnu_field
3109 save_gnu_tree
3114 }
3116 /* Then we build the parent subtype. If it has discriminants but
3117 the type itself has unknown discriminants, this means that it
3118 doesn't contain information about how the discriminants are
3119 derived from those of the ancestor type, so it cannot be used
3120 directly. Instead it is built by cloning the parent subtype
3121 of the underlying record view of the type, for which the above
3122 derivation of discriminants has been made explicit. */
3125 {
3128 /* If we are defining the type, the underlying record
3129 view must already have been elaborated at this point.
3130 Otherwise do it now as its parent subtype cannot be
3131 technically elaborated on its own. */
3134 else
3139 /* Substitute the "get to the parent" of the type for that
3140 of its underlying record view in the cloned type. */
3145 {
3147 tree gnu_ref
3150 gnu_parent
3152 }
3153 }
3154 else
3157 /* The parent field needs strict alignment so, if it is to
3158 be created with a component clause below, then we need
3159 to apply the same adjustment as in gnat_to_gnu_field. */
3163 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
3164 initially built. The discriminants must reference the fields
3165 of the parent subtype and not those of its base type for the
3166 placeholder machinery to properly work. */
3168 {
3169 /* The actual parent subtype is the full view. */
3171 {
3174 else
3176 }
3182 {
3183 Entity_Id field;
3192 }
3193 }
3195 /* The "get to the parent" COMPONENT_REF must be given its
3196 proper type... */
3199 /* ...and reference the _Parent field of this record. */
3200 gnu_field
3203 has_rep
3205 has_rep
3211 }
3213 /* Make the fields for the discriminants and put them into the record
3214 unless it's an Unchecked_Union. */
3219 {
3220 /* If this is a record extension and this discriminant is the
3221 renaming of another discriminant, we've handled it above. */
3226 /* However, if we are just annotating types, the Parent_Subtype
3227 doesn't exist so we need skip the discriminant altogether. */
3234 gnu_field
3236 debug_info_p);
3238 /* Make an expression using a PLACEHOLDER_EXPR from the
3239 FIELD_DECL node just created and link that with the
3240 corresponding GNAT defining identifier. */
3248 {
3251 }
3252 }
3254 /* If we have a derived untagged type that renames discriminants in
3255 the root type, the (stored) discriminants are a just copy of the
3256 discriminants of the root type. This means that any constraints
3257 added by the renaming in the derivation are disregarded as far
3258 as the layout of the derived type is concerned. To rescue them,
3259 we change the type of the (stored) discriminants to a subtype
3260 with the bounds of the type of the visible discriminants. */
3262 && !is_extension
3268 /* Ignore access discriminants. */
3271 {
3275 /* If the scope of the discriminant is not the record type,
3276 this means that we're processing the implicit full view
3277 of a type derived from a private discriminated type: in
3278 this case, the Stored_Constraint list is simply copied
3279 from the partial view, see Build_Derived_Private_Type.
3280 So we need to retrieve the corresponding discriminant
3281 of the implicit full view, otherwise we will abort. */
3283 {
3284 Entity_Id field;
3293 }
3296 gnu_ref
3300 /* GNU_REF must be an expression using a PLACEHOLDER_EXPR built
3301 just above for one of the stored discriminants. */
3305 {
3307 tree gnu_subtype
3318 }
3319 }
3321 /* Add the fields into the record type and finish it up. */
3329 /* Fill in locations of fields. */
3332 /* If there are any entities in the chain corresponding to components
3333 that we did not elaborate, ensure we elaborate their types if they
3334 are Itypes. */
3344 /* If this is a record type associated with an exception definition,
3345 equate its fields to those of the standard exception type. This
3346 will make it possible to convert between them. */
3348 {
3349 tree gnu_std_field;
3352 gnu_field;
3357 }
3358 }
3362 /* If an equivalent type is present, that is what we should use.
3363 Otherwise, fall through to handle this like a record subtype
3364 since it may have constraints. */
3366 {
3370 }
3372 /* fall through */
3375 /* If Cloned_Subtype is Present it means this record subtype has
3376 identical layout to that type or subtype and we should use
3377 that GCC type for this one. The front end guarantees that
3378 the component list is shared. */
3380 {
3385 }
3387 /* Otherwise, first ensure the base type is elaborated. Then, if we are
3388 changing the type, make a new type with each field having the type of
3389 the field in the new subtype but the position computed by transforming
3390 every discriminant reference according to the constraints. We don't
3391 see any difference between private and non-private type here since
3392 derivations from types should have been deferred until the completion
3393 of the private type. */
3394 else
3395 {
3397 tree gnu_base_type;
3400 {
3401 defer_incomplete_level++;
3403 }
3405 gnu_base_type
3409 {
3412 }
3414 /* If this is a record subtype associated with a dispatch table,
3415 strip the suffix. This is necessary to make sure 2 different
3416 subtypes associated with the imported and exported views of a
3417 dispatch table are properly merged in LTO mode. */
3419 {
3426 }
3428 /* When the subtype has discriminants and these discriminants affect
3429 the initial shape it has inherited, factor them in. But for an
3430 Unchecked_Union (it must be an Itype), just return the type.
3431 We can't just test Is_Constrained because private subtypes without
3432 discriminants of types with discriminants with default expressions
3433 are Is_Constrained but aren't constrained! */
3440 {
3446 Entity_Id gnat_field;
3458 /* Set the size, alignment and alias set of the new type to
3459 match that of the old one, doing required substitutions. */
3461 gnu_subst_list);
3465 else
3468 /* Look for REP and variant parts in the base type. */
3472 /* If there is a variant part, we must compute whether the
3473 constraints statically select a particular variant. If
3474 so, we simply drop the qualified union and flatten the
3475 list of fields. Otherwise we'll build a new qualified
3476 union for the variants that are still relevant. */
3478 {
3482 gnu_variant_list
3484 gnu_subst_list,
3485 vNULL);
3487 /* If all the qualifiers are unconditionally true, the
3488 innermost variant is statically selected. */
3492 {
3495 }
3497 /* Otherwise, create the new variants. */
3500 {
3503 tree suffix
3505 IDENTIFIER_POINTER
3513 gnu_subst_list);
3515 }
3516 }
3517 else
3518 {
3521 }
3523 /* Make a list of fields and their position in the base type. */
3524 gnu_pos_list
3531 /* Now go down every component in the subtype and compute its
3532 size and position from those of the component in the base
3533 type and from the constraints of the subtype. */
3541 && Underlying_Type
3544 {
3546 Entity_Id gnat_old_field
3548 tree gnu_old_field
3554 /* If the type is the same, retrieve the GCC type from the
3555 old field to take into account possible adjustments. */
3558 else
3561 /* If there was a component clause, the field types must be
3562 the same for the type and subtype, so copy the data from
3563 the old field to avoid recomputation here. Also if the
3564 field is justified modular and the optimization in
3565 gnat_to_gnu_field was applied. */
3571 {
3574 }
3576 /* If the old field was packed and of constant size, we
3577 have to get the old size here, as it might differ from
3578 what the Etype conveys and the latter might overlap
3579 onto the following field. Try to arrange the type for
3580 possible better packing along the way. */
3584 {
3589 gnu_field_type
3591 }
3593 else
3596 /* If the context of the old field is the base type or its
3597 REP part (if any), put the field directly in the new
3598 type; otherwise look up the context in the variant list
3599 and put the field either in the new type if there is a
3600 selected variant or in one of the new variants. */
3602 || (gnu_rep_part
3605 else
3606 {
3609 tree rep_part;
3617 {
3620 else
3622 }
3623 else
3624 /* The front-end may pass us "ghost" components if
3625 it fails to recognize that a constrained subtype
3626 is statically constrained. Discard them. */
3628 }
3630 /* Now create the new field modeled on the old one. */
3631 gnu_field
3637 /* Put it in one of the new variants directly. */
3639 {
3642 }
3644 /* To match the layout crafted in components_to_record,
3645 if this is the _Tag or _Parent field, put it before
3646 any other fields. */
3651 /* Similarly, if this is the _Controller field, put
3652 it before the other fields except for the _Tag or
3653 _Parent field. */
3655 {
3658 }
3660 /* Otherwise, if this is a regular field, put it after
3661 the other fields. */
3662 else
3663 {
3670 }
3673 }
3675 /* If there is a variant list, a selected variant and the fields
3676 all have a constant position, put them in order of increasing
3677 position to match that of constant CONSTRUCTORs. Likewise if
3678 there is no variant list but a REP part, since the latter has
3679 been flattened in the process. */
3683 {
3695 {
3698 }
3699 }
3701 /* If there is a variant list and no selected variant, we need
3702 to create the nest of variant parts from the old nest. */
3704 {
3705 tree new_variant_part
3711 }
3713 /* Now go through the entities again looking for Itypes that
3714 we have not elaborated but should (e.g., Etypes of fields
3715 that have Original_Components). */
3723 /* We will output additional debug info manually below. */
3728 /* Fill in locations of fields. */
3731 /* If debugging information is being written for the type and if
3732 we are asked to output such encodings, write a record that
3733 shows what we are a subtype of and also make a variable that
3734 indicates our size, if still variable. */
3736 {
3738 tree gnu_unpad_base_name
3746 build_reference_type
3748 gnu_subtype_marker,
3765 }
3769 }
3771 /* Otherwise, go down all the components in the new type and make
3772 them equivalent to those in the base type. */
3773 else
3774 {
3784 gnat_to_gnu_field_decl
3787 }
3788 }
3793 /* Use the special descriptor type for dispatch tables if needed,
3794 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3795 Note that we are only required to do so for static tables in
3796 order to be compatible with the C++ ABI, but Ada 2005 allows
3797 to extend library level tagged types at the local level so
3798 we do it in the non-static case as well. */
3801 {
3805 }
3807 /* fall through */
3814 {
3815 /* The designated type and its equivalent type for gigi. */
3818 /* Whether it comes from a limited with. */
3819 const bool is_from_limited_with
3822 /* The "full view" of the designated type. If this is an incomplete
3823 entity from a limited with, treat its non-limited view as the full
3824 view. Otherwise, if this is an incomplete or private type, use the
3825 full view. In the former case, we might point to a private type,
3826 in which case, we need its full view. Also, we want to look at the
3827 actual type used for the representation, so this takes a total of
3828 three steps. */
3829 Entity_Id gnat_desig_full_direct_first
3830 = (is_from_limited_with
3834 Entity_Id gnat_desig_full_direct
3835 = ((is_from_limited_with
3840 Entity_Id gnat_desig_full
3842 /* The type actually used to represent the designated type, either
3843 gnat_desig_full or gnat_desig_equiv. */
3844 Entity_Id gnat_desig_rep;
3845 /* We want to know if we'll be seeing the freeze node for any
3846 incomplete type we may be pointing to. */
3847 const bool in_main_unit
3851 /* True if we make a dummy type here. */
3853 /* The mode to be used for the pointer type. */
3855 /* The GCC type used for the designated type. */
3861 /* If either the designated type or its full view is an unconstrained
3862 array subtype, replace it with the type it's a subtype of. This
3863 avoids problems with multiple copies of unconstrained array types.
3864 Likewise, if the designated type is a subtype of an incomplete
3865 record type, use the parent type to avoid order of elaboration
3866 issues. This can lose some code efficiency, but there is no
3867 alternative. */
3878 /* Set the type that's the representation of the designated type. */
3879 gnat_desig_rep
3882 /* If we already know what the full type is, use it. */
3886 /* Get the type of the thing we are to point to and build a pointer to
3887 it. If it is a reference to an incomplete or private type with a
3888 full view that is a record or an array, make a dummy type node and
3889 get the actual type later when we have verified it is safe. */
3895 /* Likewise if this is a reference to a record, an array or a
3896 subprogram type and we are to defer elaborating incomplete
3897 types. We do this because this access type may be the full
3898 view of a private type. */
3905 /* If this is a reference from a limited_with type back to our
3906 main unit and there's a freeze node for it, either we have
3907 already processed the declaration and made the dummy type,
3908 in which case we just reuse the latter, or we have not yet,
3909 in which case we make the dummy type and it will be reused
3910 when the declaration is finally processed. In both cases,
3911 the pointer eventually created below will be automatically
3912 adjusted when the freeze node is processed. */
3913 || (in_main_unit
3914 && is_from_limited_with
3916 {
3919 }
3921 /* Otherwise handle the case of a pointer to itself. */
3923 {
3924 gnu_type
3928 }
3930 /* If expansion is disabled, the equivalent type of a concurrent type
3931 is absent, so we use the void pointer type. */
3935 /* If the ultimately designated type is an incomplete type with no full
3936 view, we use the void pointer type in LTO mode to avoid emitting a
3937 dummy type in the GIMPLE IR. We cannot do that in regular mode as
3938 the name of the dummy type in used by GDB for a global lookup. */
3944 /* Finally, handle the default case where we can just elaborate our
3945 designated type. */
3946 else
3949 /* It is possible that a call to gnat_to_gnu_type above resolved our
3950 type. If so, just return it. */
3952 {
3955 }
3957 /* Access-to-unconstrained-array types need a special treatment. */
3959 {
3960 /* If the processing above got something that has a pointer, then
3961 we are done. This could have happened either because the type
3962 was elaborated or because somebody else executed the code. */
3967 }
3969 /* If we haven't done it yet, build the pointer type the usual way. */
3971 {
3972 /* Modify the designated type if we are pointing only to constant
3973 objects, but don't do it for a dummy type. */
3976 gnu_desig_type
3979 gnu_type
3982 }
3984 /* If the designated type is not declared in the main unit and we made
3985 a dummy node for it, save our definition, elaborate the actual type
3986 and replace the dummy type we made with the actual one. But if we
3987 are to defer actually looking up the actual type, make an entry in
3988 the deferred list instead. If this is from a limited with, we may
3989 have to defer until the end of the current unit. */
3991 {
3993 gnu_type
3999 gnat_entity);
4006 {
4009 }
4010 else
4011 {
4014 = (is_from_limited_with
4021 }
4022 }
4023 }
4028 /* If we are just annotating types and have no equivalent record type,
4029 just use the void pointer type. */
4033 /* The run-time representation is the equivalent type. */
4034 else
4035 {
4038 }
4040 /* The designated subtype must be elaborated as well, if it does
4041 not have its own freeze node. */
4052 /* We treat this as identical to its base type; any constraint is
4053 meaningful only to the front-end. */
4056 /* The designated subtype must be elaborated as well, if it does
4057 not have its own freeze node. But designated subtypes created
4058 for constrained components of records with discriminants are
4059 not frozen by the front-end and not elaborated here, because
4060 their use may appear before the base type is frozen and it is
4061 not clear that they are needed in gigi. With the current model,
4062 there is no correct place where they could be elaborated. */
4067 {
4068 /* If we are to defer elaborating incomplete types, make a dummy
4069 type node and elaborate it later. */
4071 {
4074 p->old_type
4079 }
4082 Incomplete_Or_Private_Kind))
4085 }
4090 /* Subprogram Entities
4092 The following access functions are defined for subprograms:
4094 Etype Return type or Standard_Void_Type.
4095 First_Formal The first formal parameter.
4096 Is_Imported Indicates that the subprogram has appeared in
4097 an INTERFACE or IMPORT pragma. For now we
4098 assume that the external language is C.
4099 Is_Exported Likewise but for an EXPORT pragma.
4100 Is_Inlined True if the subprogram is to be inlined.
4102 Each parameter is first checked by calling must_pass_by_ref on its
4103 type to determine if it is passed by reference. For parameters which
4104 are copied in, if they are Ada In Out or Out parameters, their return
4105 value becomes part of a record which becomes the return type of the
4106 function (C function - note that this applies only to Ada procedures
4107 so there is no Ada return type). Additional code to store back the
4108 parameters will be generated on the caller side. This transformation
4109 is done here, not in the front-end.
4111 The intended result of the transformation can be seen from the
4112 equivalent source rewritings that follow:
4114 struct temp {int a,b};
4115 procedure P (A,B: In Out ...) is temp P (int A,B)
4116 begin {
4117 .. ..
4118 end P; return {A,B};
4119 }
4121 temp t;
4122 P(X,Y); t = P(X,Y);
4123 X = t.a , Y = t.b;
4125 For subprogram types we need to perform mainly the same conversions to
4126 GCC form that are needed for procedures and function declarations. The
4127 only difference is that at the end, we make a type declaration instead
4128 of a function declaration. */
4133 {
4134 tree gnu_ext_name
4136 enum inline_status_t inline_status
4138 ? is_suppressed
4140 ? is_required
4143 /* Subprograms marked both Intrinsic and Always_Inline need not
4144 have a body of their own. */
4145 bool extern_flag
4147 || imported_p
4150 tree gnu_param_list;
4152 /* A parameter may refer to this type, so defer completion of any
4153 incomplete types. */
4155 {
4156 defer_incomplete_level++;
4158 }
4160 /* If the subprogram has an alias, it is probably inherited, so
4161 we can use the original one. If the original "subprogram"
4162 is actually an enumeration literal, it may be the first use
4163 of its type, so we must elaborate that type now. */
4165 {
4172 gnu_decl
4175 /* Elaborate any Itypes in the parameters of this entity. */
4182 /* Materialize renamed subprograms in the debugging information
4183 when the renamed object is compile time known. We can consider
4184 such renamings as imported declarations.
4186 Because the parameters in generics instantiation are generally
4187 materialized as renamings, we ofter end up having both the
4188 renamed subprogram and the renaming in the same context and with
4189 the same name: in this case, renaming is both useless debug-wise
4190 and potentially harmful as name resolution in the debugger could
4191 return twice the same entity! So avoid this case. */
4200 && gnu_decl
4202 {
4207 }
4210 }
4212 /* Get the GCC tree for the (underlying) subprogram type. If the
4213 entity is an actual subprogram, also get the parameter list. */
4214 gnu_type
4218 {
4222 }
4224 /* Deal with platform-specific calling conventions. */
4226 prepend_one_attribute
4229 gnat_entity);
4231 prepend_one_attribute
4234 gnat_entity);
4236 /* If we should request stack realignment for a foreign convention
4237 subprogram, do so. Note that this applies to task entry points
4238 in particular. */
4241 prepend_one_attribute
4244 gnat_entity);
4246 /* Deal with a pragma Linker_Section on a subprogram. */
4252 /* If we are defining the subprogram and it has an Address clause
4253 we must get the address expression from the saved GCC tree for the
4254 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4255 the address expression here since the front-end has guaranteed
4256 in that case that the elaboration has no effects. If there is
4257 an Address clause and we are not defining the object, just
4258 make it a constant. */
4260 {
4264 gnu_address
4271 /* Convert the type of the object to a reference type that can
4272 alias everything as per RM 13.3(19). */
4273 gnu_type
4278 gnu_decl
4284 }
4286 /* If this is a mere subprogram type, just create the declaration. */
4288 {
4291 gnu_decl
4294 }
4296 /* Otherwise create the subprogram declaration with the external name,
4297 the type and the parameter list. However, if this a reference to
4298 the allocation routines, reuse the canonical declaration nodes as
4299 they come with special properties. */
4300 else
4301 {
4306 else
4307 {
4308 gnu_decl
4317 }
4318 }
4319 }
4330 {
4331 const bool is_from_limited_with
4333 /* Get the "full view" of this entity. If this is an incomplete
4334 entity from a limited with, treat its non-limited view as the
4335 full view. Otherwise, use either the full view or the underlying
4336 full view, whichever is present. This is used in all the tests
4337 below. */
4338 const Entity_Id full_view
4339 = is_from_limited_with
4347 /* If this is an incomplete type with no full view, it must be a Taft
4348 Amendment type or an incomplete type coming from a limited context,
4349 in which cases we return a dummy type. Otherwise, we just get the
4350 type from its Etype. */
4352 {
4354 {
4357 }
4358 else
4359 {
4360 gnu_decl
4363 }
4364 }
4366 /* Or else, if we already made a type for the full view, reuse it. */
4370 /* Or else, if we are not defining the type or there is no freeze
4371 node on it, get the type for the full view. Likewise if this is
4372 a limited_with'ed type not declared in the main unit, which can
4373 happen for incomplete formal types instantiated on a type coming
4374 from a limited_with clause. */
4377 || (is_from_limited_with
4379 {
4382 }
4384 /* Otherwise, make a dummy type entry which will be replaced later.
4385 Save it as the full declaration's type so we can do any needed
4386 updates when we see it. */
4387 else
4388 {
4394 }
4395 }
4399 /* Class-wide types are always transformed into their root type. */
4408 /* If we are just annotating types and have no equivalent record type,
4409 just return void_type, except for root types that have discriminants
4410 because the discriminants will very likely be used in the declarative
4411 part of the associated body so they need to be translated. */
4413 {
4416 {
4418 Entity_Id gnat_field;
4420 /* This is a minimal version of the E_Record_Type handling. */
4427 {
4428 tree gnu_field
4440 }
4444 }
4445 else
4447 }
4449 /* Concurrent types are always transformed into their record type. */
4450 else
4461 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4462 we've already saved it, so we don't try to. */
4468 /* This is a SPARK annotation that only reaches here when compiling in
4469 ASIS mode. */
4477 }
4479 /* If we had a case where we evaluated another type and it might have
4480 defined this one, handle it here. */
4482 {
4485 }
4487 /* If we are processing a type and there is either no decl for it or
4488 we just made one, do some common processing for the type, such as
4489 handling alignment and possible padding. */
4491 {
4494 /* Process the attributes, if not already done. Note that the type is
4495 already defined so we cannot pass true for IN_PLACE here. */
4498 /* Tell the middle-end that objects of tagged types are guaranteed to
4499 be properly aligned. This is necessary because conversions to the
4500 class-wide type are translated into conversions to the root type,
4501 which can be less aligned than some of its derived types. */
4506 /* Record whether the type is passed by reference. */
4510 /* ??? Don't set the size for a String_Literal since it is either
4511 confirming or we don't handle it properly (if the low bound is
4512 non-constant). */
4514 {
4517 gnu_size
4520 }
4522 /* If a size was specified, see if we can make a new type of that size
4523 by rearranging the type, for example from a fat to a thin pointer. */
4525 {
4526 gnu_type
4533 }
4535 /* If the alignment has not already been processed and this is not
4536 an unconstrained array type, see if an alignment is specified.
4537 If not, we pick a default alignment for atomic objects. */
4539 ;
4541 {
4545 /* Warn on suspiciously large alignments. This should catch
4546 errors about the (alignment,byte)/(size,bit) discrepancy. */
4548 {
4549 tree size;
4551 /* If a size was specified, take it into account. Otherwise
4552 use the RM size for records or unions as the type size has
4553 already been adjusted to the alignment. */
4559 else
4562 /* Consider an alignment as suspicious if the alignment/size
4563 ratio is greater or equal to the byte/bit ratio. */
4568 gnat_entity);
4569 }
4570 }
4581 /* See if we need to pad the type. If we did, and made a record,
4582 the name of the new type may be changed. So get it back for
4583 us when we make the new TYPE_DECL below. */
4591 /* Now set the RM size of the type. We cannot do it before padding
4592 because we need to accept arbitrary RM sizes on integral types. */
4595 /* If we are at global level, GCC will have applied variable_size to
4596 the type, but that won't have done anything. So, if it's not
4597 a constant or self-referential, call elaborate_expression_1 to
4598 make a variable for the size rather than calculating it each time.
4599 Handle both the RM size and the actual size. */
4604 {
4611 /* ??? For now, store the size as a multiple of the alignment in
4612 bytes so that we can see the alignment from the tree. */
4618 /* ??? gnu_type may come from an existing type so the MULT_EXPR node
4619 may not be marked by the call to create_type_decl below. */
4623 {
4628 {
4632 /* If the position of the variant part is constant, subtract
4633 it from the size of the type of the parent to get the new
4634 size. This manual CSE reduces the data size. */
4636 {
4644 }
4645 else
4646 {
4652 /* ??? For now, store the size as a multiple of the
4653 alignment in bytes so that we can see the alignment
4654 from the tree. */
4661 /* ??? For now, store the offset as a multiple of the
4662 alignment in bytes so that we can see the alignment
4663 from the tree. */
4667 DECL_OFFSET_ALIGN
4669 }
4673 }
4677 else
4678 ada_size
4682 }
4683 }
4685 /* Similarly, if this is a record type or subtype at global level, call
4686 elaborate_expression_2 on any field position. Skip any fields that
4687 we haven't made trees for to avoid problems with class-wide types. */
4692 {
4695 /* ??? For now, store the offset as a multiple of the alignment
4696 in bytes so that we can see the alignment from the tree. */
4699 {
4706 /* ??? The context of gnu_field is not necessarily gnu_type
4707 so the MULT_EXPR node built above may not be marked by
4708 the call to create_type_decl below. */
4710 }
4711 }
4716 /* If this is not an unconstrained array type, set some flags. */
4718 {
4725 /* If it is passed by reference, force BLKmode to ensure that
4726 objects of this type will always be put in memory. */
4733 {
4734 const int quals
4735 = TYPE_QUAL_VOLATILE
4738 }
4739 }
4741 /* If this is a derived type, relate its alias set to that of its parent
4742 to avoid troubles when a call to an inherited primitive is inlined in
4743 a context where a derived object is accessed. The inlined code works
4744 on the parent view so the resulting code may access the same object
4745 using both the parent and the derived alias sets, which thus have to
4746 conflict. As the same issue arises with component references, the
4747 parent alias set also has to conflict with composite types enclosing
4748 derived components. For instance, if we have:
4750 type D is new T;
4751 type R is record
4752 Component : D;
4753 end record;
4755 we want T to conflict with both D and R, in addition to R being a
4756 superset of D by record/component construction.
4758 One way to achieve this is to perform an alias set copy from the
4759 parent to the derived type. This is not quite appropriate, though,
4760 as we don't want separate derived types to conflict with each other:
4762 type I1 is new Integer;
4763 type I2 is new Integer;
4765 We want I1 and I2 to both conflict with Integer but we do not want
4766 I1 to conflict with I2, and an alias set copy on derivation would
4767 have that effect.
4769 The option chosen is to make the alias set of the derived type a
4770 superset of that of its parent type. It trivially fulfills the
4771 simple requirement for the Integer derivation example above, and
4772 the component case as well by superset transitivity:
4774 superset superset
4775 R ----------> D ----------> T
4777 However, for composite types, conversions between derived types are
4778 translated into VIEW_CONVERT_EXPRs so a sequence like:
4780 type Comp1 is new Comp;
4781 type Comp2 is new Comp;
4782 procedure Proc (C : Comp1);
4784 C : Comp2;
4785 Proc (Comp1 (C));
4787 is translated into:
4789 C : Comp2;
4790 Proc ((Comp1 &) &VIEW_CONVERT_EXPR <Comp1> (C));
4792 and gimplified into:
4794 C : Comp2;
4795 Comp1 *C.0;
4796 C.0 = (Comp1 *) &C;
4797 Proc (C.0);
4799 i.e. generates code involving type punning. Therefore, Comp1 needs
4800 to conflict with Comp2 and an alias set copy is required.
4802 The language rules ensure the parent type is already frozen here. */
4806 {
4808 /* For constrained packed array subtypes, the implementation type is
4809 used instead of the nominal type. */
4817 }
4822 gnat_entity);
4823 else
4824 {
4827 }
4828 }
4830 /* If we got a type that is not dummy, back-annotate the alignment of the
4831 type if not already in the tree. Likewise for the size, if any. */
4833 {
4837 {
4841 /* If the default alignment of "double" or larger scalar types is
4842 specifically capped and this is not an array with an alignment
4843 clause on the component type, return the cap. */
4845 is_capped_double
4848 is_capped_double
4850 else
4855 else
4859 }
4862 {
4865 /* If the size is self-referential, annotate the maximum value. */
4869 /* If we are just annotating types and the type is tagged, the tag
4870 and the parent components are not generated by the front-end so
4871 alignment and sizes must be adjusted if there is no rep clause. */
4878 {
4879 tree offset;
4882 {
4886 }
4887 else
4888 {
4889 unsigned int align
4893 }
4896 offset
4904 }
4906 /* If there is a rep clause, only adjust alignment and Esize. */
4908 {
4909 unsigned int align
4914 }
4916 /* Otherwise no adjustment is needed. */
4917 else
4919 }
4923 }
4925 /* If we haven't already, associate the ..._DECL node that we just made with
4926 the input GNAT entity node. */
4930 /* Now we are sure gnat_entity has a corresponding ..._DECL node,
4931 eliminate as many deferred computations as possible. */
4934 /* If this is an enumeration or floating-point type, we were not able to set
4935 the bounds since they refer to the type. These are always static. */
4938 {
4942 /* If this is a padded type, we need to use the underlying type. */
4946 /* If this is a floating point type and we haven't set a floating
4947 point type yet, use this in the evaluation of the bounds. */
4955 {
4956 /* Enumeration types have specific RM bounds. */
4959 }
4960 else
4961 {
4962 /* Floating-point types don't have specific RM bounds. */
4965 }
4966 }
4968 /* If we deferred processing of incomplete types, re-enable it. If there
4969 were no other disables and we have deferred types to process, do so. */
4973 {
4976 /* We are back to level 0 for the deferring of incomplete types.
4977 But processing these incomplete types below may itself require
4978 deferring, so preserve what we have and restart from scratch. */
4983 {
4990 }
4991 }
4993 /* If we are not defining this type, see if it's on one of the lists of
4994 incomplete types. If so, handle the list entry now. */
4996 {
5001 {
5005 }
5009 {
5015 }
5016 }
5019 force_global--;
5021 /* If this is a packed array type whose original array type is itself
5022 an Itype without freeze node, make sure the latter is processed. */
5030 }
5032 /* Similar, but if the returned value is a COMPONENT_REF, return the
5033 FIELD_DECL. */
5035 tree
5037 {
5044 }
5046 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5047 the GCC type corresponding to that entity. */
5049 tree
5051 {
5052 tree gnu_decl;
5054 /* The back end never attempts to annotate generic types. */
5062 }
5064 /* Similar, but GNAT_ENTITY is assumed to refer to a GNAT type. Return
5065 the unpadded version of the GCC type corresponding to that entity. */
5067 tree
5069 {
5076 }
5078 /* Return whether the E_Subprogram_Type/E_Function/E_Procedure GNAT_ENTITY is
5079 a C++ imported method or equivalent.
5081 We use the predicate on 32-bit x86/Windows to find out whether we need to
5082 use the "thiscall" calling convention for GNAT_ENTITY. This convention is
5083 used for C++ methods (functions with METHOD_TYPE) by the back-end. */
5085 bool
5087 {
5088 /* Check that the subprogram has C++ convention. */
5092 /* A constructor is a method on the C++ side. We deal with it now because
5093 it is declared without the 'this' parameter in the sources and, although
5094 the front-end will create a version with the 'this' parameter for code
5095 generation purposes, we want to return true for both versions. */
5099 /* And that the type of the first parameter (indirectly) has it too. */
5110 /* This is the main case: C++ method imported as a primitive operation.
5111 Note that a C++ class with no virtual functions can be imported as a
5112 limited record type so the operation is not necessarily dispatching. */
5116 /* A thunk needs to be handled like its associated primitive operation. */
5120 /* This is set on the E_Subprogram_Type built for a dispatching call. */
5125 }
5127 /* Finalize the processing of From_Limited_With incomplete types. */
5129 void
5131 {
5138 {
5142 {
5147 }
5150 }
5151 }
5153 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
5154 kind of type (such E_Task_Type) that has a different type which Gigi
5155 uses for its representation. If the type does not have a special type
5156 for its representation, return GNAT_ENTITY. If a type is supposed to
5157 exist, but does not, abort unless annotating types, in which case
5158 return Empty. If GNAT_ENTITY is Empty, return Empty. */
5160 Entity_Id
5162 {
5169 {
5195 }
5198 }
5200 /* Return a GCC tree for a type corresponding to the component type of the
5201 array type or subtype GNAT_ARRAY. DEFINITION is true if this component
5202 is for an array being defined. DEBUG_INFO_P is true if we need to write
5203 debug information for other types that we may create in the process. */
5205 static tree
5208 {
5211 tree gnu_comp_size;
5214 /* If an alignment is specified, use it as a cap on the component type
5215 so that it can be honored for the whole type. But ignore it for the
5216 original type of packed array types. */
5220 else
5223 /* Try to get a smaller form of the component if needed. */
5236 /* Get and validate any specified Component_Size. */
5237 gnu_comp_size
5242 /* If the array has aliased components and the component size can be zero,
5243 force at least unit size to ensure that the components have distinct
5244 addresses. */
5250 gnu_comp_size
5253 /* If the component type is a RECORD_TYPE that has a self-referential size,
5254 then use the maximum size for the component size. */
5260 /* Honor the component size. This is not needed for bit-packed arrays. */
5262 {
5268 else
5274 /* If a padding record was made, declare it now since it will never be
5275 declared otherwise. This is necessary to ensure that its subtrees
5276 are properly marked. */
5279 gnat_array);
5280 }
5282 /* If the component type is a padded type made for a non-bit-packed array
5283 of scalars with reverse storage order, we need to propagate the reverse
5284 storage order to the padding type since it is the innermost enclosing
5285 aggregate type around the scalar. */
5293 {
5294 const int quals
5295 = TYPE_QUAL_VOLATILE
5298 }
5301 }
5303 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM, to be placed
5304 in the parameter list of GNAT_SUBPROG. GNU_PARAM_TYPE is the GCC tree for
5305 the type of the parameter. FIRST is true if this is the first parameter in
5306 the list of GNAT_SUBPROG. Also set CICO to true if the parameter must use
5307 the copy-in copy-out implementation mechanism.
5309 The returned tree is a PARM_DECL, except for the cases where no parameter
5310 needs to be actually passed to the subprogram; the type of this "shadow"
5311 parameter is then returned instead. */
5313 static tree
5316 {
5322 /* The parameter can be indirectly modified if its address is taken. */
5328 tree gnu_param;
5330 /* Make sure to use the proper SLOC for vector ABI warnings. */
5334 /* Builtins are expanded inline and there is no real call sequence involved.
5335 So the type expected by the underlying expander is always the type of the
5336 argument "as is". */
5341 /* Handle the first parameter of a valued procedure specially: it's a copy
5342 mechanism for which the parameter is never allocated. */
5344 {
5348 }
5350 /* Or else, see if a Mechanism was supplied that forced this parameter
5351 to be passed one way or another. */
5353 ;
5355 /* Positive mechanism means by copy for sufficiently small parameters. */
5357 {
5362 else
5364 }
5366 /* Otherwise, it's an unsupported mechanism so error out. */
5367 else
5368 {
5371 }
5373 /* If this is either a foreign function or if the underlying type won't
5374 be passed by reference and is as aligned as the original type, strip
5375 off possible padding type. */
5377 {
5386 }
5388 /* If this is a read-only parameter, make a variant of the type that is
5389 read-only. ??? However, if this is an unconstrained array, that type
5390 can be very complex, so skip it for now. Likewise for any other
5391 self-referential type. */
5397 /* For foreign conventions, pass arrays as pointers to the element type.
5398 First check for unconstrained array and get the underlying array. */
5400 gnu_param_type
5403 /* For GCC builtins, pass Address integer types as (void *) */
5409 /* Arrays are passed as pointers to element type for foreign conventions. */
5411 {
5412 /* Strip off any multi-dimensional entries, then strip
5413 off the last array to get the component type. */
5422 gnu_param_type
5426 }
5428 /* Fat pointers are passed as thin pointers for foreign conventions. */
5430 gnu_param_type
5433 /* If we were requested or muss pass by reference, do so.
5434 If we were requested to pass by copy, do so.
5435 Otherwise, for foreign conventions, pass In Out or Out parameters
5436 or aggregates by reference. For COBOL and Fortran, pass all
5437 integer and FP types that way too. For Convention Ada, use
5438 the standard Ada default. */
5442 && ((foreign
5444 || (foreign
5449 || (!foreign
5451 {
5452 /* We take advantage of 6.2(12) by considering that references built for
5453 parameters whose type isn't by-ref and for which the mechanism hasn't
5454 been forced to by-ref allow only a restricted form of aliasing. */
5455 restricted_aliasing_p
5459 }
5461 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
5470 /* If this is an Out parameter that isn't passed by reference and isn't
5471 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
5472 it will be a VAR_DECL created when we process the procedure, so just
5473 return its type. For the special parameter of a valued procedure,
5474 never pass it in.
5476 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
5477 Out parameters with discriminants or implicit initial values to be
5478 handled like In Out parameters. These type are normally built as
5479 aggregates, hence passed by reference, except for some packed arrays
5480 which end up encoded in special integer types. Note that scalars can
5481 be given implicit initial values using the Default_Value aspect.
5483 The exception we need to make is then for packed arrays of records
5484 with discriminants or implicit initial values. We have no light/easy
5485 way to check for the latter case, so we merely check for packed arrays
5486 of records. This may lead to useless copy-in operations, but in very
5487 rare cases only, as these would be exceptions in a set of already
5488 exceptional situations. */
5490 && !by_ref
5491 && (by_return
5510 /* If no Mechanism was specified, indicate what we're using, then
5511 back-annotate it. */
5517 }
5519 /* Associate GNAT_SUBPROG with GNU_TYPE, which must be a dummy type, so that
5520 GNAT_SUBPROG is updated when GNU_TYPE is completed.
5522 Ada 2012 (AI05-019) says that freezing a subprogram does not always freeze
5523 the corresponding profile, which means that, by the time the freeze node
5524 of the subprogram is encountered, types involved in its profile may still
5525 be not yet frozen. That's why we need to update GNAT_SUBPROG when we see
5526 the freeze node of types involved in its profile, either types of formal
5527 parameters or the return type. */
5529 static void
5531 {
5539 {
5544 }
5546 /* Even if there is already a slot for GNU_TYPE, we need to set the flag
5547 because the vector might have been just emptied by update_profiles_with.
5548 This can happen when there are 2 freeze nodes associated with different
5549 views of the same type; the type will be really complete only after the
5550 second freeze node is encountered. */
5555 /* Make sure GNAT_SUBPROG is not associated twice with the same dummy type,
5556 since this would mean updating twice its profile. */
5558 {
5562 /* Entity_Id is a simple integer so we can implement a stable order on
5563 the vector with an ordered insertion scheme and binary search. */
5565 {
5572 else
5574 }
5576 /* l == u and therefore is the insertion point. */
5578 }
5579 else
5583 }
5585 /* Update the GCC tree previously built for the profile of GNAT_SUBPROG. */
5587 static void
5589 {
5590 tree gnu_param_list;
5595 {
5596 /* Builtins cannot have their address taken so we can reset them. */
5601 }
5607 /* If GNAT_SUBPROG is an actual subprogram, GNU_SUBPROG is a FUNCTION_DECL
5608 and needs to be adjusted too. */
5610 {
5612 tree gnu_ext_name
5617 }
5618 }
5620 /* Update the GCC trees previously built for the profiles involving GNU_TYPE,
5621 a dummy type which appears in profiles. */
5623 void
5625 {
5633 /* The flag needs to be reset before calling update_profile, in case
5634 associate_subprog_with_dummy_type is again invoked on GNU_TYPE. */
5643 }
5645 /* Return the GCC tree for GNAT_TYPE present in the profile of a subprogram.
5647 Ada 2012 (AI05-0151) says that incomplete types coming from a limited
5648 context may now appear as parameter and result types. As a consequence,
5649 we may need to defer their translation until after a freeze node is seen
5650 or to the end of the current unit. We also aim at handling temporarily
5651 incomplete types created by the usual delayed elaboration scheme. */
5653 static tree
5655 {
5656 /* This is the same logic as the E_Access_Type case of gnat_to_gnu_entity
5657 so the rationale is exposed in that place. These processings probably
5658 ought to be merged at some point. */
5660 const bool is_from_limited_with
5663 Entity_Id gnat_full_direct_first
5664 = (is_from_limited_with
5668 Entity_Id gnat_full_direct
5669 = ((is_from_limited_with
5677 tree gnu_type;
5683 && ((!in_main_unit
5690 {
5694 {
5701 }
5702 }
5707 else
5710 /* Access-to-unconstrained-array types need a special treatment. */
5712 {
5715 }
5718 }
5720 /* Return a GCC tree for a subprogram type corresponding to GNAT_SUBPROG.
5721 DEFINITION is true if this is for a subprogram being defined. DEBUG_INFO_P
5722 is true if we need to write debug information for other types that we may
5723 create in the process. Also set PARAM_LIST to the list of parameters.
5724 If GNAT_SUBPROG is bound to a GCC builtin, return the DECL for the builtin
5725 directly instead of its type. */
5727 static tree
5730 {
5733 Entity_Id gnat_param;
5736 tree gnu_return_type;
5739 /* Non-null for subprograms containing parameters passed by copy-in copy-out
5740 (In Out or Out parameters not passed by reference), in which case it is
5741 the list of nodes used to specify the values of the In Out/Out parameters
5742 that are returned as a record upon procedure return. The TREE_PURPOSE of
5743 an element of this list is a FIELD_DECL of the record and the TREE_VALUE
5744 is the PARM_DECL corresponding to that field. This list will be saved in
5745 the TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
5748 /* Fields in return type of procedure with copy-in copy-out parameters. */
5750 /* The semantics of "pure" in Ada essentially matches that of "const"
5751 in the back-end. In particular, both properties are orthogonal to
5752 the "nothrow" property if the EH circuitry is explicit in the
5753 internal representation of the back-end. If we are to completely
5754 hide the EH circuitry from it, we need to declare that calls to pure
5755 Ada subprograms that can throw have side effects since they can
5756 trigger an "abnormal" transfer of control flow; thus they can be
5757 neither "const" nor "pure" in the back-end sense. */
5765 /* Look into the return type and get its associated GCC tree if it is not
5766 void, and then compute various flags for the subprogram type. But make
5767 sure not to do this processing multiple times. */
5774 {
5779 }
5781 else
5782 {
5786 else
5789 /* If this function returns by reference, make the actual return type
5790 the reference type and make a note of that. */
5792 {
5795 }
5797 /* If the return type is an unconstrained array type, the return value
5798 will be allocated on the secondary stack so the actual return type
5799 is the fat pointer type. */
5801 {
5804 }
5806 /* This is the same unconstrained array case, but for a dummy type. */
5809 {
5812 }
5814 /* Likewise, if the return type requires a transient scope, the return
5815 value will also be allocated on the secondary stack so the actual
5816 return type is the reference type. */
5818 {
5821 }
5823 /* If the Mechanism is By_Reference, ensure this function uses the
5824 target's by-invisible-reference mechanism, which may not be the
5825 same as above (e.g. it might be passing an extra parameter). */
5829 /* Likewise, if the return type is itself By_Reference. */
5833 /* If the type is a padded type and the underlying type would not be
5834 passed by reference or the function has a foreign convention, return
5835 the underlying type. */
5837 && (!default_pass_by_ref
5842 /* If the return type is unconstrained, it must have a maximum size.
5843 Use the padded type as the effective return type. And ensure the
5844 function uses the target's by-invisible-reference mechanism to
5845 avoid copying too much data when it returns. */
5847 {
5851 /* If the size overflows to 0, set it to an arbitrary positive
5852 value so that assignments in the type are preserved. Their
5853 actual size is independent of this positive value. */
5857 {
5860 }
5866 /* Declare it now since it will never be declared otherwise. This
5867 is necessary to ensure that its subtrees are properly marked. */
5874 }
5876 /* If the return type has a size that overflows, we usually cannot have
5877 a function that returns that type. This usage doesn't really make
5878 sense anyway, so issue an error here. */
5883 {
5888 }
5890 /* If the return type is incomplete, there are 2 cases: if the function
5891 returns by reference, then the return type is only linked indirectly
5892 in the profile, so the profile can be seen as complete since it need
5893 not be further modified, only the reference types need be adjusted;
5894 otherwise the profile is incomplete and need be adjusted too. */
5896 {
5899 }
5903 || return_by_direct_ref_p
5904 || return_by_invisi_ref_p
5906 }
5908 /* A procedure (something that doesn't return anything) shouldn't be
5909 considered const since there would be no reason for calling such a
5910 subprogram. Note that procedures with Out (or In Out) parameters
5911 have already been converted into a function with a return type.
5912 Similarly, if the function returns an unconstrained type, then the
5913 function will allocate the return value on the secondary stack and
5914 thus calls to it cannot be CSE'ed, lest the stack be reclaimed. */
5918 /* Loop over the parameters and get their associated GCC tree. While doing
5919 this, build a copy-in copy-out structure if we need one. */
5923 {
5924 const bool mech_is_by_ref
5931 /* Fetch an existing parameter with complete type and reuse it. But we
5932 didn't save the CICO property so we can only do it for In parameters
5933 or parameters passed by reference. */
5938 {
5941 }
5943 /* Otherwise translate the parameter type and act accordingly. */
5944 else
5945 {
5951 else
5954 /* If the parameter type is incomplete, there are 2 cases: if it is
5955 passed by reference, then the type is only linked indirectly in
5956 the profile, so the profile can be seen as complete since it need
5957 not be further modified, only the reference type need be adjusted;
5958 otherwise the profile is incomplete and need be adjusted too. */
5960 {
5961 Node_Id gnat_decl;
5965 && TYPE_IS_FAT_POINTER_P
5968 {
5970 gnu_param
5980 }
5982 /* ??? This is a kludge to support null procedures in spec taking
5983 a parameter with an untagged incomplete type coming from a
5984 limited context. The front-end creates a body without knowing
5985 anything about the non-limited view, which is illegal Ada and
5986 cannot be supported. Create a parameter with a fake type. */
5994 else
5995 {
5996 /* Build a minimal PARM_DECL without DECL_ARG_TYPE so that
5997 Call_to_gnu will stop if it encounters the PARM_DECL. */
5998 gnu_param
6000 gnu_param_type);
6002 gnu_param_type);
6004 }
6005 }
6007 /* Otherwise build the parameter declaration normally. */
6008 else
6009 {
6010 gnu_param
6014 /* We are returned either a PARM_DECL or a type if no parameter
6015 needs to be passed; in either case, adjust the type. */
6018 else
6019 {
6022 }
6023 }
6024 }
6026 /* If we have a GCC tree for the parameter, register it. */
6029 {
6030 gnu_param_type_list
6035 /* If a parameter is a pointer, a function may modify memory through
6036 it and thus shouldn't be considered a const function. Also, the
6037 memory may be modified between two calls, so they can't be CSE'ed.
6038 The latter case also handles by-ref parameters. */
6042 }
6044 /* If the parameter uses the copy-in copy-out mechanism, allocate a field
6045 for it in the return type and register the association. */
6047 {
6049 {
6052 /* If this is a function, we also need a field for the
6053 return value to be placed. */
6055 {
6056 tree gnu_field
6058 gnu_return_type,
6064 gnu_cico_list
6066 }
6069 /* Set a default alignment to speed up accesses. But we should
6070 not increase the size of the structure too much, lest it does
6071 not fit in return registers anymore. */
6074 }
6076 tree gnu_field
6085 }
6086 }
6088 /* If the subprogram uses the copy-in copy-out mechanism, possibly adjust
6089 and finish up the return type. */
6091 {
6092 /* If we have a CICO list but it has only one entry, we convert
6093 this function into a function that returns this object. */
6097 /* Do not finalize the return type if the subprogram is stubbed
6098 since structures are incomplete for the back-end. */
6100 {
6104 /* Try to promote the mode of the return type if it is passed
6105 in registers, again to speed up accesses. */
6108 NULL_TREE))
6109 {
6110 unsigned int size
6113 machine_mode mode;
6119 {
6127 }
6128 }
6132 }
6135 }
6137 /* The lists have been built in reverse. */
6143 /* If the profile is incomplete, we only set the (temporary) return and
6144 parameter types; otherwise, we build the full type. In either case,
6145 we reuse an already existing GCC tree that we built previously here. */
6147 {
6149 ;
6150 else
6157 }
6158 else
6159 {
6161 {
6170 }
6171 else
6172 {
6173 gnu_type
6176 /* GNU_TYPE may be shared since GCC hashes types. Unshare it if it
6177 has a different TYPE_CI_CO_LIST or flags. */
6179 return_unconstrained_p,
6180 return_by_direct_ref_p,
6181 return_by_invisi_ref_p))
6182 {
6188 }
6189 }
6197 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
6198 corresponding DECL node and check the parameter association. */
6201 {
6205 /* If we have a builtin DECL for that function, use it. Check if
6206 the profiles are compatible and warn if they are not. Note that
6207 the checker is expected to post diagnostics in this case. */
6209 {
6210 intrin_binding_t inb
6214 post_error
6216 gnat_subprog);
6219 }
6221 /* Inability to find the builtin DECL most often indicates a genuine
6222 mistake, but imports of unregistered intrinsics are sometimes used
6223 on purpose to allow hooking in alternate bodies; we post a warning
6224 conditioned on Wshadow in this case, to let developers be notified
6225 on demand without risking false positives with common default sets
6226 of options. */
6229 }
6230 }
6233 }
6235 /* Return the external name for GNAT_SUBPROG given its entity name. */
6237 static tree
6239 {
6242 /* If there was no specified Interface_Name and the external and
6243 internal names of the subprogram are the same, only use the
6244 internal name to allow disambiguation of nested subprograms. */
6249 }
6251 /* Like build_qualified_type, but TYPE_QUALS is added to the existing
6252 qualifiers on TYPE. */
6254 static tree
6256 {
6258 }
6260 /* Set TYPE_NONALIASED_COMPONENT on an array type built by means of
6261 build_nonshared_array_type. */
6263 static void
6265 {
6268 }
6270 /* Set TYPE_REVERSE_STORAGE_ORDER on an array type built by means of
6271 build_nonshared_array_type. */
6273 static void
6275 {
6278 }
6280 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
6282 static bool
6284 {
6291 return
6293 }
6295 /* Return true if the array type GNU_TYPE, which represents a dimension of
6296 GNAT_TYPE, has a non-aliased component in the back-end sense. */
6298 static bool
6300 {
6301 /* If the array type is not the innermost dimension of the GNAT type,
6302 then it has a non-aliased component. */
6307 /* If the array type has an aliased component in the front-end sense,
6308 then it also has an aliased component in the back-end sense. */
6312 /* If this is a derived type, then it has a non-aliased component if
6313 and only if its parent type also has one. */
6315 {
6319 gnu_parent_type
6324 }
6326 /* Otherwise, rely exclusively on properties of the element type. */
6328 }
6330 /* Return true if GNAT_ADDRESS is a value known at compile-time. */
6332 static bool
6334 {
6335 /* Catch System'To_Address. */
6340 }
6342 /* Return true if GNAT_RANGE, a N_Range node, cannot be superflat, i.e. if the
6343 inequality HB >= LB-1 is true. LB and HB are the low and high bounds. */
6345 static bool
6347 {
6349 Node_Id scalar_range;
6352 /* If the low bound is not constant, try to find an upper bound. */
6361 /* If the high bound is not constant, try to find a lower bound. */
6370 /* If we have failed to find constant bounds, punt. */
6375 /* We need at least a signed 64-bit type to catch most cases. */
6381 /* If the low bound is the smallest integer, nothing can be smaller. */
6387 }
6389 /* Return true if GNU_EXPR is (essentially) the address of a CONSTRUCTOR. */
6391 static bool
6393 {
6401 }
6403 /* Return true if the size in units represented by GNU_SIZE can be handled by
6404 an allocation. If STATIC_P is true, consider only what can be done with a
6405 static allocation. */
6407 static bool
6409 {
6410 /* We can allocate a fixed size if it is a valid for the middle-end. */
6414 /* We can allocate a variable size if this isn't a static allocation. */
6415 else
6417 }
6419 /* Return true if GNU_EXPR needs a conversion to GNU_TYPE when used as the
6420 initial value of an object of GNU_TYPE. */
6422 static bool
6424 {
6425 /* Do not convert if the object's type is unconstrained because this would
6426 generate useless evaluations of the CONSTRUCTOR to compute the size. */
6431 /* Do not convert if the object's type is a padding record whose field is of
6432 self-referential size because we want to copy only the actual data. */
6436 /* Do not convert a call to a function that returns with variable size since
6437 we want to use the return slot optimization in this case. */
6442 /* Do not convert to a record type with a variant part from a record type
6443 without one, to keep the object simpler. */
6450 /* In all the other cases, convert the expression to the object's type. */
6452 }
6453 \f
6454 /* Given GNAT_ENTITY, elaborate all expressions that are required to
6455 be elaborated at the point of its definition, but do nothing else. */
6457 void
6459 {
6461 {
6468 {
6472 /* ??? Tests to avoid Constraint_Error in static expressions
6473 are needed until after the front stops generating bogus
6474 conversions on bounds of real types. */
6482 }
6489 {
6490 Node_Id gnat_discriminant_expr;
6491 Entity_Id gnat_field;
6495 gnat_discriminant_expr
6500 /* Ignore access discriminants. */
6505 }
6508 }
6509 }
6510 \f
6511 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
6512 NAME, ARGS and ERROR_POINT. */
6514 static void
6517 tree attr_name,
6518 tree attr_args,
6519 Node_Id attr_error_point)
6520 {
6530 }
6532 /* Prepend to ATTR_LIST an entry for an attribute provided by GNAT_PRAGMA. */
6534 static void
6536 {
6541 /* Map the pragma at hand. Skip if this isn't one we know how to handle. */
6543 {
6574 }
6576 /* See what arguments we have and turn them into GCC trees for attribute
6577 handlers. These expect identifier for strings. We handle at most two
6578 arguments and static expressions only. */
6580 {
6586 {
6590 {
6594 }
6597 }
6601 {
6606 }
6607 }
6609 /* Prepend to the list. Make a list of the argument we might have, as GCC
6610 expects it. */
6612 gnu_arg1
6616 }
6618 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
6620 static void
6622 {
6623 Node_Id gnat_temp;
6625 /* Attributes are stored as Representation Item pragmas. */
6631 }
6632 \f
6633 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
6634 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
6635 return the GCC tree to use for that expression. S is the suffix to use
6636 if a variable needs to be created and DEFINITION is true if this is done
6637 for a definition of GNAT_ENTITY. If NEED_VALUE is true, we need a result;
6638 otherwise, we are just elaborating the expression for side-effects. If
6639 NEED_DEBUG is true, we need a variable for debugging purposes even if it
6640 isn't needed for code generation. */
6642 static tree
6645 {
6646 tree gnu_expr;
6648 /* If we already elaborated this expression (e.g. it was involved
6649 in the definition of a private type), use the old value. */
6653 /* If we don't need a value and this is static or a discriminant,
6654 we don't need to do anything. */
6661 /* If it's a static expression, we don't need a variable for debugging. */
6665 /* Otherwise, convert this tree to its GCC equivalent and elaborate it. */
6669 /* Save the expression in case we try to elaborate this entity again. Since
6670 it's not a DECL, don't check it. Don't save if it's a discriminant. */
6675 }
6677 /* Similar, but take a GNU expression and always return a result. */
6679 static tree
6682 {
6687 /* If GNU_EXPR contains a placeholder, just return it. We rely on the fact
6688 that an expression cannot contain both a discriminant and a variable. */
6692 /* If GNU_EXPR is neither a constant nor based on a read-only variable, make
6693 a variable that is initialized to contain the expression when the package
6694 containing the definition is elaborated. If this entity is defined at top
6695 level, replace the expression by the variable; otherwise use a SAVE_EXPR
6696 if this is necessary. */
6699 else
6700 {
6701 /* Skip any conversions and simple constant arithmetics to see if the
6702 expression is based on a read-only variable. */
6710 expr_variable_p
6711 = !(inner
6714 }
6716 /* We only need to use the variable if we are in a global context since GCC
6717 can do the right thing in the local case. However, when not optimizing,
6718 use it for bounds of loop iteration scheme to avoid code duplication. */
6719 use_variable = expr_variable_p
6720 && (expr_global_p
6721 || (!optimize
6722 && definition
6727 /* Now create it, possibly only for debugging purposes. */
6729 {
6730 /* The following variable creation can happen when processing the body
6731 of subprograms that are defined out of the extended main unit and
6732 inlined. In this case, we are not at the global scope, and thus the
6733 new variable must not be tagged "external", as we used to do here as
6734 soon as DEFINITION was false. */
6735 tree gnu_decl
6742 /* Using this variable at debug time (if need_debug is true) requires a
6743 proper location. The back-end will compute a location for this
6744 variable only if the variable is used by the generated code.
6745 Returning the variable ensures the caller will use it in generated
6746 code. Note that there is no need for a location if the debug info
6747 contains an integer constant.
6748 TODO: when the encoding-based debug scheme is dropped, move this
6749 condition to the top-level IF block: we will not need to create a
6750 variable anymore in such cases, then. */
6753 }
6756 }
6758 /* Similar, but take an alignment factor and make it explicit in the tree. */
6760 static tree
6763 {
6765 return
6768 gnu_expr,
6769 unit_align),
6771 need_debug),
6772 unit_align);
6773 }
6775 /* Structure to hold internal data for elaborate_reference. */
6777 struct er_data
6778 {
6779 Entity_Id entity;
6782 };
6784 /* Wrapper function around elaborate_expression_1 for elaborate_reference. */
6786 static tree
6788 {
6792 /* This is what elaborate_expression_1 does if NEED_DEBUG is false. */
6796 /* If this is a COMPONENT_REF of a fat pointer, elaborate the entire fat
6797 pointer. This may be more efficient, but will also allow us to more
6798 easily find the match for the PLACEHOLDER_EXPR. */
6806 return
6808 }
6810 /* Elaborate the reference REF to be used as renamed object for GNAT_ENTITY.
6811 DEFINITION is true if this is done for a definition of GNAT_ENTITY and
6812 INIT is set to the first arm of a COMPOUND_EXPR present in REF, if any. */
6814 static tree
6817 {
6820 }
6821 \f
6822 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
6823 the value passed against the list of choices. */
6825 tree
6827 {
6828 Node_Id choice;
6829 Node_Id gnat_temp;
6834 {
6836 {
6841 this_test
6855 this_test
6865 /* This represents either a subtype range, an enumeration
6866 literal, or a constant Ekind says which. If an enumeration
6867 literal or constant, fall through to the next case. */
6870 {
6876 this_test
6883 }
6885 /* fall through */
6891 single);
6900 }
6903 this_test);
6904 }
6907 }
6908 \f
6909 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
6910 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
6912 static int
6914 {
6915 /* If the field contains an item of variable size, we cannot pack it
6916 because we cannot create temporaries of non-fixed size in case
6917 we need to take the address of the field. See addressable_p and
6918 the notes on the addressability issues for further details. */
6922 /* In the other cases, we can honor the packing. */
6926 /* If the alignment of the record is specified and the field type
6927 is over-aligned, request Storage_Unit alignment for the field. */
6932 /* Likewise if the maximum alignment of the record is specified. */
6938 }
6940 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
6941 placed in GNU_RECORD_TYPE.
6943 PACKED is 1 if the enclosing record is packed or -1 if the enclosing
6944 record has Component_Alignment of Storage_Unit.
6946 DEFINITION is true if this field is for a record being defined.
6948 DEBUG_INFO_P is true if we need to write debug information for types
6949 that we may create in the process. */
6951 static tree
6954 {
6956 const bool is_aliased
6958 const bool is_atomic
6960 const bool is_independent
6962 const bool is_volatile
6964 const bool needs_strict_alignment
6965 = (is_aliased
6966 || is_independent
6967 || is_volatile
6973 /* If this field requires strict alignment, we cannot pack it because
6974 it would very likely be under-aligned in the record. */
6977 else
6980 /* If a size is specified, use it. Otherwise, if the record type is packed,
6981 use the official RM size. See "Handling of Type'Size Values" in Einfo
6982 for further details. */
6989 else
6992 /* If we have a specified size that is smaller than that of the field's type,
6993 or a position is specified, and the field's type is a record that doesn't
6994 require strict alignment, see if we can get either an integral mode form
6995 of the type or a smaller form. If we can, show a size was specified for
6996 the field if there wasn't one already, so we know to make this a bitfield
6997 and avoid making things wider.
6999 Changing to an integral mode form is useful when the record is packed as
7000 we can then place the field at a non-byte-aligned position and so achieve
7001 tighter packing. This is in addition required if the field shares a byte
7002 with another field and the front-end lets the back-end handle the access
7003 to the field, because GCC cannot handle non-byte-aligned BLKmode fields.
7005 Changing to a smaller form is required if the specified size is smaller
7006 than that of the field's type and the type contains sub-fields that are
7007 padded, in order to avoid generating accesses to these sub-fields that
7008 are wider than the field.
7010 We avoid the transformation if it is not required or potentially useful,
7011 as it might entail an increase of the field's alignment and have ripple
7012 effects on the outer record type. A typical case is a field known to be
7013 byte-aligned and not to share a byte with another field. */
7019 || (gnu_size
7025 {
7028 {
7032 }
7033 }
7039 {
7041 Entity_Id gnat_parent
7048 /* Ensure the position does not overlap with the parent subtype, if there
7049 is one. This test is omitted if the parent of the tagged type has a
7050 full rep clause since, in this case, component clauses are allowed to
7051 overlay the space allocated for the parent type and the front-end has
7052 checked that there are no overlapping components. */
7054 {
7059 post_error_ne_tree
7062 }
7064 /* If this field needs strict alignment, make sure that the record is
7065 sufficiently aligned and that the position and size are consistent
7066 with the type. But don't do it if we are just annotating types and
7067 the field's type is tagged, since tagged types aren't fully laid out
7068 in this mode. Also, note that atomic implies volatile so the inner
7069 test sequences ordering is significant here. */
7072 {
7078 /* If the position is not a multiple of the alignment of the type,
7079 then error out and reset the position. */
7082 {
7096 else
7100 type_align);
7102 }
7105 {
7109 /* If the size is lower than that of the type, or greater for
7110 atomic and aliased, then error out and reset the size. */
7112 {
7126 else
7130 gnu_type_size);
7132 }
7134 /* Likewise if the size is not a multiple of a byte, */
7136 bitsize_unit_node)))
7137 {
7149 else
7154 }
7155 }
7156 }
7157 }
7159 /* If the record has rep clauses and this is the tag field, make a rep
7160 clause for it as well. */
7163 {
7166 }
7168 else
7169 {
7172 /* If we are packing the record and the field is BLKmode, round the
7173 size up to a byte boundary. */
7176 }
7178 /* We need to make the size the maximum for the type if it is
7179 self-referential and an unconstrained type. In that case, we can't
7180 pack the field since we can't make a copy to align it. */
7182 && !gnu_size
7185 {
7188 }
7190 /* If a size is specified, adjust the field's type to it. */
7192 {
7193 tree orig_field_type;
7195 /* If the field's type is justified modular, we would need to remove
7196 the wrapper to (better) meet the layout requirements. However we
7197 can do so only if the field is not aliased to preserve the unique
7198 layout and if the prescribed size is not greater than that of the
7199 packed array to preserve the justification. */
7207 /* Similarly if the field's type is a misaligned integral type, but
7208 there is no restriction on the size as there is no justification. */
7214 gnu_field_type
7222 /* If a padding record was made, declare it now since it will never be
7223 declared otherwise. This is necessary to ensure that its subtrees
7224 are properly marked. */
7229 }
7231 /* Otherwise (or if there was an error), don't specify a position. */
7232 else
7235 /* If the field's type is a padded type made for a scalar field of a record
7236 type with reverse storage order, we need to propagate the reverse storage
7237 order to the padding type since it is the innermost enclosing aggregate
7238 type around the scalar. */
7247 /* Now create the decl for the field. */
7248 gnu_field
7256 {
7261 }
7264 }
7265 \f
7266 /* Return true if at least one member of COMPONENT_LIST needs strict
7267 alignment. */
7269 static bool
7271 {
7272 Node_Id component_decl;
7277 {
7285 }
7288 }
7290 /* Return true if TYPE is a type with variable size or a padding type with a
7291 field of variable size or a record that has a field with such a type. */
7293 static bool
7295 {
7296 tree field;
7313 }
7314 \f
7315 /* Return true if FIELD is an artificial field. */
7317 static bool
7319 {
7320 /* These fields are generated by the front-end proper. */
7324 /* These fields are generated by gigi. */
7329 }
7331 /* Return true if FIELD is a non-artificial aliased field. */
7333 static bool
7335 {
7340 }
7342 /* Return true if FIELD is a non-artificial field with self-referential
7343 size. */
7345 static bool
7347 {
7355 }
7357 /* Return true if FIELD is a non-artificial field with variable size. */
7359 static bool
7361 {
7369 }
7371 /* qsort comparer for the bit positions of two record components. */
7373 static int
7375 {
7378 const int ret
7382 }
7384 /* Structure holding information for a given variant. */
7386 {
7387 /* The record type of the variant. */
7388 tree type;
7390 /* The name of the variant. */
7391 tree name;
7393 /* The qualifier of the variant. */
7394 tree qual;
7396 /* Whether the variant has a rep clause. */
7399 /* Whether the variant is packed. */
7404 /* Translate and chain the GNAT_COMPONENT_LIST to the GNU_FIELD_LIST, set the
7405 result as the field list of GNU_RECORD_TYPE and finish it up. Return true
7406 if GNU_RECORD_TYPE has a rep clause which affects the layout (see below).
7407 When called from gnat_to_gnu_entity during the processing of a record type
7408 definition, the GCC node for the parent, if any, will be the single field
7409 of GNU_RECORD_TYPE and the GCC nodes for the discriminants will be on the
7410 GNU_FIELD_LIST. The other calls to this function are recursive calls for
7411 the component list of a variant and, in this case, GNU_FIELD_LIST is empty.
7413 PACKED is 1 if this is for a packed record or -1 if this is for a record
7414 with Component_Alignment of Storage_Unit.
7416 DEFINITION is true if we are defining this record type.
7418 CANCEL_ALIGNMENT is true if the alignment should be zeroed before laying
7419 out the record. This means the alignment only serves to force fields to
7420 be bitfields, but not to require the record to be that aligned. This is
7421 used for variants.
7423 ALL_REP is true if a rep clause is present for all the fields.
7425 UNCHECKED_UNION is true if we are building this type for a record with a
7426 Pragma Unchecked_Union.
7428 ARTIFICIAL is true if this is a type that was generated by the compiler.
7430 DEBUG_INFO is true if we need to write debug information about the type.
7432 MAYBE_UNUSED is true if this type may be unused in the end; this doesn't
7433 mean that its contents may be unused as well, only the container itself.
7435 REORDER is true if we are permitted to reorder components of this type.
7437 FIRST_FREE_POS, if nonzero, is the first (lowest) free field position in
7438 the outer record type down to this variant level. It is nonzero only if
7439 all the fields down to this level have a rep clause and ALL_REP is false.
7441 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
7442 with a rep clause is to be added; in this case, that is all that should
7443 be done with such fields and the return value will be false. */
7445 static bool
7452 {
7453 const bool needs_xv_encodings
7468 /* For each component referenced in a component declaration create a GCC
7469 field and add it to the list, skipping pragmas in the GNAT list. */
7476 {
7480 /* If present, the _Parent field must have been created as the single
7481 field of the record type. Put it before any other fields. */
7483 {
7486 }
7487 else
7488 {
7492 /* If this is the _Tag field, put it before any other fields. */
7496 /* If this is the _Controller field, put it before the other
7497 fields except for the _Tag or _Parent field. */
7499 {
7502 }
7504 /* If this is a regular field, put it after the other fields. */
7505 else
7506 {
7512 /* And record information for the final layout. */
7517 }
7518 }
7521 }
7523 /* At the end of the component list there may be a variant part. */
7526 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
7527 mutually exclusive and should go in the same memory. To do this we need
7528 to treat each variant as a record whose elements are created from the
7529 component list for the variant. So here we create the records from the
7530 lists for the variants and put them all into the QUAL_UNION_TYPE.
7531 If this is an Unchecked_Union, we make a UNION_TYPE instead or
7532 use GNU_RECORD_TYPE if there are no fields so far. */
7534 {
7538 tree gnu_var_name
7549 gnu_union_name
7552 /* Reuse the enclosing union if this is an Unchecked_Union whose fields
7553 are all in the variant part, to match the layout of C unions. There
7554 is an associated check below. */
7557 else
7558 {
7559 gnu_union_type
7567 }
7569 /* If all the fields down to this level have a rep clause, find out
7570 whether all the fields at this level also have one. If so, then
7571 compute the new first free position to be passed downward. */
7574 {
7576 gnu_field;
7579 {
7582 this_first_free_pos
7584 }
7585 else
7586 {
7589 }
7590 }
7592 /* We build the variants in two passes. The bulk of the work is done in
7593 the first pass, that is to say translating the GNAT nodes, building
7594 the container types and computing the associated properties. However
7595 we cannot finish up the container types during this pass because we
7596 don't know where the variant part will be placed until the end. */
7600 {
7605 vinfo_t vinfo;
7613 /* Set the alignment of the inner type in case we need to make
7614 inner objects into bitfields, but then clear it out so the
7615 record actually gets only the alignment required. */
7621 /* Similarly, if the outer record has a size specified and all
7622 the fields have a rep clause, we can propagate the size. */
7624 {
7628 }
7630 /* Add the fields into the record type for the variant. Note that
7631 we aren't sure to really use it at this point, see below. */
7632 has_rep
7636 unchecked_union,
7638 this_first_free_pos,
7639 all_rep || this_first_free_pos
7642 /* Translate the qualifier and annotate the GNAT node. */
7646 /* Deal with packedness like in gnat_to_gnu_field. */
7648 {
7651 }
7652 else
7653 field_packed
7656 /* Push this variant onto the stack for the second pass. */
7664 /* Compute the global properties that will determine the placement of
7665 the variant part. */
7669 }
7671 /* Round up the first free position to the alignment of the variant part
7672 for the variants without rep clause. This will guarantee a consistent
7673 layout independently of the placement of the variant part. */
7677 /* In the second pass, the container types are adjusted if necessary and
7678 finished up, then the corresponding fields of the variant part are
7679 built with their qualifier, unless this is an unchecked union. */
7681 {
7685 /* If this is an Unchecked_Union whose fields are all in the variant
7686 part and we have a single field with no representation clause or
7687 placed at offset zero, use the field directly to match the layout
7688 of C unions. */
7690 && gnu_field_list
7694 {
7697 }
7698 else
7699 {
7700 /* Finalize the variant type now. We used to throw away empty
7701 record types but we no longer do that because we need them to
7702 generate complete debug info for the variant; otherwise, the
7703 union type definition will be lacking the fields associated
7704 with these empty variants. */
7706 {
7707 /* The variant part will be at offset 0 so we need to ensure
7708 that the fields are laid out starting from the first free
7709 position at this level. */
7711 tree gnu_rep_part;
7715 gnu_rep_part
7717 this_first_free_pos);
7722 }
7729 gnu_field
7731 gnu_union_type,
7732 all_rep_and_size
7741 }
7745 }
7747 /* Only make the QUAL_UNION_TYPE if there are non-empty variants. */
7749 {
7753 {
7757 }
7762 /* If GNU_UNION_TYPE is our record type, it means we must have an
7763 Unchecked_Union with no fields. Verify that and, if so, just
7764 return. */
7766 {
7768 && !gnu_field_list
7771 }
7776 /* Deal with packedness like in gnat_to_gnu_field. */
7779 else
7780 union_field_packed
7783 gnu_variant_part
7785 all_rep_and_size
7791 }
7792 }
7794 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses and, if we are
7795 permitted to reorder components, self-referential sizes or variable sizes.
7796 If they do, pull them out and put them onto the appropriate list. We have
7797 to do this in a separate pass since we want to handle the discriminants
7798 but can't play with them until we've used them in debugging data above.
7800 Similarly, pull out the fields with zero size and no rep clause, as they
7801 would otherwise modify the layout and thus very likely run afoul of the
7802 Ada semantics, which are different from those of C here.
7804 ??? If we reorder them, debugging information will be wrong but there is
7805 nothing that can be done about this at the moment. */
7808 #define MOVE_FROM_FIELD_LIST_TO(LIST) \
7809 do { \
7810 if (gnu_last) \
7811 DECL_CHAIN (gnu_last) = gnu_next; \
7812 else \
7813 gnu_field_list = gnu_next; \
7814 \
7815 DECL_CHAIN (gnu_field) = (LIST); \
7816 (LIST) = gnu_field; \
7817 } while (0)
7820 {
7824 {
7827 }
7831 {
7834 }
7837 {
7840 }
7843 {
7853 }
7856 }
7858 #undef MOVE_FROM_FIELD_LIST_TO
7862 /* If permitted, we reorder the fields as follows:
7864 1) all fixed length fields,
7865 2) all fields whose length doesn't depend on discriminants,
7866 3) all fields whose length depends on discriminants,
7867 4) the variant part,
7869 within the record and within each variant recursively. */
7871 gnu_field_list
7874 /* Otherwise, if there is an aliased field placed after a field whose length
7875 depends on discriminants, we put all the fields of the latter sort, last.
7876 We need to do this in case an object of this record type is mutable. */
7880 /* If P_REP_LIST is nonzero, this means that we are asked to move the fields
7881 in our REP list to the previous level because this level needs them in
7882 order to do a correct layout, i.e. avoid having overlapping fields. */
7886 /* Deal with the annoying case of an extension of a record with variable size
7887 and partial rep clause, for which the _Parent field is forced at offset 0
7888 and has variable size, which we do not support below. Note that we cannot
7889 do it if the field has fixed size because we rely on the presence of the
7890 REP part built below to trigger the reordering of the fields in a derived
7891 record type when all the fields have a fixed position. */
7895 && !variants_have_rep
7896 && first_free_pos
7899 {
7903 }
7905 /* Otherwise, sort the fields by bit position and put them into their own
7906 record, before the others, if we also have fields without rep clause. */
7908 {
7913 /* If all the fields have a rep clause, we can do a flat layout. */
7914 layout_with_rep = !gnu_field_list
7916 gnu_rep_type
7920 gnu_field;
7926 /* Put the fields in the list in order of increasing position, which
7927 means we start from the end. */
7930 {
7934 }
7938 else
7939 {
7944 /* If FIRST_FREE_POS is nonzero, we need to ensure that the fields
7945 without rep clause are laid out starting from this position.
7946 Therefore, we force it as a minimal size on the REP part. */
7947 gnu_rep_part
7950 /* Chain the REP part at the beginning of the field list. */
7953 }
7954 }
7956 /* Chain the variant part at the end of the field list. */
7968 /* Chain the fields with zero size at the beginning of the field list. */
7974 }
7975 \f
7976 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
7977 placed into an Esize, Component_Bit_Offset, or Component_Size value
7978 in the GNAT tree. */
7980 static Uint
7982 {
7983 TCode tcode;
7988 /* See if we've already saved the value for this node. */
7990 {
7998 }
7999 else
8002 /* If we do not return inside this switch, TCODE will be set to the
8003 code to use for a Create_Node operand and LEN (set above) will be
8004 the number of recursive calls for us to make. */
8007 {
8012 /* The only case we handle here is a simple discriminant reference. */
8014 {
8017 /* Climb up the chain of successive extensions, if any. */
8024 return
8026 }
8033 /* Now just list the operations we handle. */
8064 /* For negative values in sizetype, build NEGATE_EXPR of the opposite.
8065 Such values appear in expressions with aligning patterns. Note that,
8066 since sizetype is unsigned, we have to jump through some hoops. */
8068 {
8072 {
8075 }
8076 }
8080 /* In regular mode, inline back only if symbolic annotation is requested
8081 in order to avoid memory explosion on big discriminated record types.
8082 But not in ASIS mode, as symbolic annotation is required for DDA. */
8084 {
8088 }
8089 else
8092 /* fall through */
8096 }
8098 /* Now get each of the operands that's relevant for this code. If any
8099 cannot be expressed as a repinfo node, say we can't. */
8104 {
8107 else
8111 }
8115 /* Save the result in the cache. */
8117 {
8119 /* We can't assume the hash table data hasn't moved since the initial
8120 look up, so we have to search again. Allocating and inserting an
8121 entry at that point would be an alternative, but then we'd better
8122 discard the entry if we decided not to cache it. */
8128 }
8131 }
8133 /* Given GNAT_ENTITY, an object (constant, variable, parameter, exception)
8134 and GNU_TYPE, its corresponding GCC type, set Esize and Alignment to the
8135 size and alignment used by Gigi. Prefer SIZE over TYPE_SIZE if non-null.
8136 BY_REF is true if the object is used by reference. */
8138 void
8140 {
8142 {
8145 else
8147 }
8150 {
8159 }
8164 }
8166 /* Return first element of field list whose TREE_PURPOSE is the same as ELEM.
8167 Return NULL_TREE if there is no such element in the list. */
8169 static tree
8171 {
8173 {
8178 }
8180 }
8182 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding GCC type,
8183 set Component_Bit_Offset and Esize of the components to the position and
8184 size used by Gigi. */
8186 static void
8188 {
8189 Entity_Id gnat_field;
8190 tree gnu_list;
8192 /* We operate by first making a list of all fields and their position (we
8193 can get the size easily) and then update all the sizes in the tree. */
8194 gnu_list
8204 {
8206 gnu_list);
8208 {
8209 tree parent_offset;
8211 /* If we are just annotating types and the type is tagged, the tag
8212 and the parent components are not generated by the front-end so
8213 we need to add the appropriate offset to each component without
8214 representation clause. */
8218 {
8219 /* For a component appearing in the current extension, the
8220 offset is the size of the parent. */
8223 parent_offset
8225 bitsizetype);
8226 else
8230 parent_offset
8233 }
8234 else
8237 Set_Component_Bit_Offset
8239 annotate_value
8243 parent_offset)));
8247 }
8249 {
8250 /* If there is no entry, this is an inherited component whose
8251 position is the same as in the parent type. */
8254 /* If we are just annotating types, discriminants renaming those of
8255 the parent have no entry so deal with them specifically. */
8265 }
8266 }
8267 }
8268 \f
8269 /* Scan all fields in GNU_TYPE and return a TREE_LIST where TREE_PURPOSE is
8270 the FIELD_DECL and TREE_VALUE a TREE_VEC containing the byte position, the
8271 value to be placed into DECL_OFFSET_ALIGN and the bit position. The list
8272 of fields is flattened, except for variant parts if DO_NOT_FLATTEN_VARIANT
8273 is set to true. GNU_POS is to be added to the position, GNU_BITPOS to the
8274 bit position, OFFSET_ALIGN is the present offset alignment. GNU_LIST is a
8275 pre-existing list to be chained to the newly created entries. */
8277 static tree
8280 {
8281 tree gnu_field;
8284 gnu_field;
8286 {
8291 unsigned int our_offset_align
8300 /* Recurse on internal fields, flattening the nested fields except for
8301 those in the variant part, if requested. */
8303 {
8307 gnu_list
8311 else
8312 gnu_list
8316 }
8317 }
8320 }
8322 /* Return a list describing the substitutions needed to reflect the
8323 discriminant substitutions from GNAT_TYPE to GNAT_SUBTYPE. They can
8324 be in any order. The values in an element of the list are in the form
8325 of operands to SUBSTITUTE_IN_EXPR. DEFINITION is true if this is for
8326 a definition of GNAT_SUBTYPE. */
8330 {
8332 Entity_Id gnat_discrim;
8333 Node_Id gnat_constr;
8340 /* Ignore access discriminants. */
8342 {
8345 elaborate_expression
8351 }
8354 }
8356 /* Scan all fields in QUAL_UNION_TYPE and return a list describing the
8357 variants of QUAL_UNION_TYPE that are still relevant after applying
8358 the substitutions described in SUBST_LIST. GNU_LIST is a pre-existing
8359 list to be prepended to the newly created entries. */
8364 {
8365 tree gnu_field;
8368 gnu_field;
8370 {
8378 /* If the new qualifier is not unconditionally false, its variant may
8379 still be accessed. */
8381 {
8387 /* Recurse on the variant subpart of the variant, if any. */
8393 /* If the new qualifier is unconditionally true, the subsequent
8394 variants cannot be accessed. */
8397 }
8398 }
8401 }
8402 \f
8403 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
8404 corresponding to GNAT_OBJECT. If the size is valid, return an INTEGER_CST
8405 corresponding to its value. Otherwise, return NULL_TREE. KIND is set to
8406 VAR_DECL if we are specifying the size of an object, TYPE_DECL for the
8407 size of a type, and FIELD_DECL for the size of a field. COMPONENT_P is
8408 true if we are being called to process the Component_Size of GNAT_OBJECT;
8409 this is used only for error messages. ZERO_OK is true if a size of zero
8410 is permitted; if ZERO_OK is false, it means that a size of zero should be
8411 treated as an unspecified size. */
8413 static tree
8416 {
8417 Node_Id gnat_error_node;
8420 /* Return 0 if no size was specified. */
8424 /* Ignore a negative size since that corresponds to our back-annotation. */
8428 /* Find the node to use for error messages. */
8435 else
8438 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
8439 but cannot be represented in bitsizetype. */
8442 {
8445 gnat_object);
8446 else
8448 gnat_object);
8450 }
8452 /* Ignore a zero size if it is not permitted. */
8456 /* The size of objects is always a multiple of a byte. */
8459 {
8463 else
8467 }
8469 /* If this is an integral type or a packed array type, the front-end has
8470 already verified the size, so we need not do it here (which would mean
8471 checking against the bounds). However, if this is an aliased object,
8472 it may not be smaller than the type of the object. */
8477 /* If the object is a record that contains a template, add the size of the
8478 template to the specified size. */
8484 /* If a type needs strict alignment, a component of this type in
8485 a packed record cannot be packed and thus uses the type size. */
8488 else
8491 /* Modify the size of a discriminated type to be the maximum size. */
8495 /* If this is an access type or a fat pointer, the minimum size is that given
8496 by the smallest integral mode that's valid for pointers. */
8498 {
8503 }
8505 /* Issue an error either if the default size of the object isn't a constant
8506 or if the new size is smaller than it. */
8510 {
8512 post_error_ne_tree
8515 else
8516 post_error_ne_tree
8520 }
8523 }
8524 \f
8525 /* Similarly, but both validate and process a value of RM size. This routine
8526 is only called for types. */
8528 static void
8530 {
8531 Node_Id gnat_attr_node;
8534 /* Do nothing if no size was specified. */
8538 /* Ignore a negative size since that corresponds to our back-annotation. */
8542 /* Only issue an error if a Value_Size clause was explicitly given.
8543 Otherwise, we'd be duplicating an error on the Size clause. */
8544 gnat_attr_node
8547 /* Get the size as an INTEGER_CST. Issue an error if a size was specified
8548 but cannot be represented in bitsizetype. */
8551 {
8554 gnat_entity);
8556 }
8558 /* Ignore a zero size unless a Value_Size clause exists, or a size clause
8559 exists, or this is an integer type, in which case the front-end will
8560 have always set it. */
8569 /* If the old size is self-referential, get the maximum size. */
8573 /* Issue an error either if the old size of the object isn't a constant or
8574 if the new size is smaller than it. The front-end has already verified
8575 this for scalar and packed array types. */
8583 && TYPE_PACKED_ARRAY_TYPE_P
8586 {
8588 post_error_ne_tree
8592 }
8594 /* Otherwise, set the RM size proper for integral types... */
8601 /* ...or the Ada size for record and union types. */
8605 }
8606 \f
8607 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
8608 a type or object whose present alignment is ALIGN. If this alignment is
8609 valid, return it. Otherwise, give an error and return ALIGN. */
8611 static unsigned int
8613 {
8616 Node_Id gnat_error_node;
8618 /* Don't worry about checking alignment if alignment was not specified
8619 by the source program and we already posted an error for this entity. */
8623 /* Post the error on the alignment clause if any. Note, for the implicit
8624 base type of an array type, the alignment clause is on the first
8625 subtype. */
8633 gnat_error_node =
8636 else
8639 /* Within GCC, an alignment is an integer, so we must make sure a value is
8640 specified that fits in that range. Also, there is an upper bound to
8641 alignments we can support/allow. */
8649 {
8653 /* If the default alignment of "double" or larger scalar types is
8654 specifically capped and the new alignment is above the cap, do
8655 not post an error and change the alignment only if there is an
8656 alignment clause; this makes it possible to have the associated
8657 GCC type overaligned by default for performance reasons. */
8659 {
8660 Entity_Id gnat_type
8662 is_capped_double
8664 }
8666 {
8667 Entity_Id gnat_type
8669 is_capped_double
8671 }
8672 else
8676 {
8679 }
8680 else
8681 {
8688 }
8689 }
8690 else
8691 {
8695 }
8698 }
8699 \f
8700 /* Verify that TYPE is something we can implement atomically. If not, issue
8701 an error for GNAT_ENTITY. COMPONENT_P is true if we are being called to
8702 process a component type. */
8704 static void
8706 {
8708 Node_Id gnat_node;
8709 machine_mode mode;
8712 tree size;
8714 /* If this is an anonymous base type, nothing to check, the error will be
8715 reported on the source type if need be. */
8724 /* Consider all aligned floating-point types atomic and any aligned types
8725 that are represented by integers no wider than a machine word. */
8732 /* For the moment, also allow anything that has an alignment equal to its
8733 size and which is smaller than a word. */
8744 {
8745 unsigned char pragma_id
8750 {
8753 }
8754 }
8762 else
8765 }
8766 \f
8768 /* Helper for the intrin compatibility checks family. Evaluate whether
8769 two types are definitely incompatible. */
8771 static bool
8773 {
8788 {
8795 /* Assume designated types are ok. We'd need to account for char * and
8796 void * variants to do better, which could rapidly get messy and isn't
8797 clearly worth the effort. */
8802 }
8805 }
8807 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8808 on the Ada/builtin argument lists for the INB binding. */
8810 static bool
8812 {
8818 /* Sequence position of the last argument we checked. */
8822 {
8826 /* If we've exhausted both lists simultaneously, we're done. */
8830 /* If one list is shorter than the other, they fail to match. */
8834 /* If we're done with the Ada args and not with the internal builtin
8835 args, or the other way around, complain. */
8838 {
8841 }
8845 {
8849 }
8851 /* Otherwise, check that types match for the current argument. */
8852 argpos ++;
8854 {
8858 }
8863 }
8866 }
8868 /* Helper for intrin_profiles_compatible_p, to perform compatibility checks
8869 on the Ada/builtin return values for the INB binding. */
8871 static bool
8873 {
8877 /* Accept function imported as procedure, common and convenient. */
8882 /* If return type is Address (integer type), map it to void *. */
8886 /* Check return types compatibility otherwise. Note that this
8887 handles void/void as well. */
8889 {
8893 }
8896 }
8898 /* Check and return whether the Ada and gcc builtin profiles bound by INB are
8899 compatible. Issue relevant warnings when they are not.
8901 This is intended as a light check to diagnose the most obvious cases, not
8902 as a full fledged type compatibility predicate. It is the programmer's
8903 responsibility to ensure correctness of the Ada declarations in Imports,
8904 especially when binding straight to a compiler internal. */
8906 static bool
8908 {
8909 /* Check compatibility on return values and argument lists, each responsible
8910 for posting warnings as appropriate. Ensure use of the proper sloc for
8911 this purpose. */
8924 }
8925 \f
8926 /* Return a FIELD_DECL node modeled on OLD_FIELD. FIELD_TYPE is its type
8927 and RECORD_TYPE is the type of the parent. If SIZE is nonzero, it is the
8928 specified size for this field. POS_LIST is a position list describing
8929 the layout of OLD_FIELD and SUBST_LIST a substitution list to be applied
8930 to this layout. */
8932 static tree
8936 {
8948 /* If the position is now a constant, we can set it as the position of the
8949 field when we make it. Otherwise, we need to deal with it specially. */
8952 else
8955 new_field
8961 {
8963 /* Finalize the position. */
8972 }
8980 }
8982 /* Create the REP part of RECORD_TYPE with REP_TYPE. If MIN_SIZE is nonzero,
8983 it is the minimal size the REP_PART must have. */
8985 static tree
8987 {
8988 tree field;
8998 }
9000 /* Return the REP part of RECORD_TYPE, if any. Otherwise return NULL. */
9002 static tree
9004 {
9007 /* The REP part is the first field, internal, another record, and its name
9008 starts with an 'R'. */
9016 }
9018 /* Return the variant part of RECORD_TYPE, if any. Otherwise return NULL. */
9020 tree
9022 {
9023 tree field;
9025 /* The variant part is the only internal field that is a qualified union. */
9032 }
9034 /* Return a new variant part modeled on OLD_VARIANT_PART. VARIANT_LIST is
9035 the list of variants to be used and RECORD_TYPE is the type of the parent.
9036 POS_LIST is a position list describing the layout of fields present in
9037 OLD_VARIANT_PART and SUBST_LIST a substitution list to be applied to this
9038 layout. */
9040 static tree
9045 {
9053 /* First create the type of the variant part from that of the old one. */
9059 /* If the position of the variant part is constant, subtract it from the
9060 size of the type of the parent to get the new size. This manual CSE
9061 reduces the code size when not optimizing. */
9063 {
9073 first_bit));
9076 }
9077 else
9080 /* Now finish up the new variants and populate the union type. */
9082 {
9086 /* Skip variants that don't belong to this nesting level. */
9090 /* Retrieve the list of fields already added to the new variant. */
9094 /* If the old variant had a variant subpart, we need to create a new
9095 variant subpart and add it to the field list. */
9099 {
9100 tree new_variant_subpart
9105 }
9107 /* Finish up the new variant and create the field. No need for debug
9108 info thanks to the XVS type. */
9112 Empty);
9114 new_field
9122 }
9124 /* Finish up the union type and create the variant part. No need for debug
9125 info thanks to the XVS type. Note that we don't reverse the field list
9126 because VARIANT_LIST has been traversed in reverse order. */
9130 Empty);
9132 new_variant_part
9138 /* With multiple discriminants it is possible for an inner variant to be
9139 statically selected while outer ones are not; in this case, the list
9140 of fields of the inner variant is not flattened and we end up with a
9141 qualified union with a single member. Drop the useless container. */
9143 {
9152 }
9155 }
9157 /* Copy the size (and alignment and alias set) from OLD_TYPE to NEW_TYPE,
9158 which are both RECORD_TYPE, after applying the substitutions described
9159 in SUBST_LIST. */
9161 static void
9164 {
9188 SET_TYPE_ADA_SIZE
9192 /* Finalize the size. */
9195 }
9197 /* Associate to GNU_TYPE, the translation of GNAT_ENTITY, which is
9198 the implementation type of a packed array type (Is_Packed_Array_Impl_Type),
9199 the original array type if it has been translated. This association is a
9200 parallel type for GNAT encodings or a debug type for standard DWARF. Note
9201 that for standard DWARF, we also want to get the original type name. */
9203 static void
9205 {
9206 Entity_Id gnat_original_array_type
9208 tree gnu_original_array_type;
9219 {
9227 }
9228 else
9230 }
9231 \f
9232 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a
9233 type with all size expressions that contain F in a PLACEHOLDER_EXPR
9234 updated by replacing F with R.
9236 The function doesn't update the layout of the type, i.e. it assumes
9237 that the substitution is purely formal. That's why the replacement
9238 value R must itself contain a PLACEHOLDER_EXPR. */
9240 tree
9242 {
9243 tree nt;
9248 {
9254 /* First the domain types of arrays. */
9257 {
9269 SET_TYPE_INDEX_TYPE
9273 }
9275 /* Then the subtypes. */
9278 {
9290 }
9302 /* These should never show up here. */
9306 {
9326 }
9331 {
9333 tree field;
9335 /* Start out with no fields, make new fields, and chain them
9336 in. If we haven't actually changed the type of any field,
9337 discard everything we've done and return the old type. */
9342 {
9347 {
9350 }
9354 {
9357 }
9359 /* Do the substitution inside the qualifier, if any. */
9361 {
9364 {
9367 }
9368 }
9375 }
9385 }
9389 }
9390 }
9391 \f
9392 /* Return the RM size of GNU_TYPE. This is the actual number of bits
9393 needed to represent the object. */
9395 tree
9397 {
9398 /* For integral types, we store the RM size explicitly. */
9402 /* Return the RM size of the actual data plus the size of the template. */
9405 return
9410 /* For record or union types, we store the size explicitly. */
9416 /* For other types, this is just the size. */
9418 }
9419 \f
9420 /* Return the name to be used for GNAT_ENTITY. If a type, create a
9421 fully-qualified name, possibly with type information encoding.
9422 Otherwise, return the name. */
9426 {
9429 }
9431 tree
9433 {
9436 }
9438 /* Return an identifier representing the external name to be used for
9439 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
9440 and the specified suffix. */
9442 tree
9444 {
9452 /* A variable using the Stdcall convention lives in a DLL. We adjust
9453 its name to use the jump table, the _imp__NAME contains the address
9454 for the NAME variable. */
9457 {
9463 }
9466 }
9468 /* Given GNU_NAME, an IDENTIFIER_NODE containing a name and SUFFIX, a
9469 string, return a new IDENTIFIER_NODE that is the concatenation of
9470 the name followed by "___" and the specified suffix. */
9472 tree
9474 {
9481 }
9483 /* Initialize data structures of the decl.c module. */
9485 void
9487 {
9488 /* Initialize the cache of annotated values. */
9491 /* Initialize the association of dummy types with subprograms. */
9493 }
9495 /* Destroy data structures of the decl.c module. */
9497 void
9499 {
9500 /* Destroy the cache of annotated values. */
9504 /* Destroy the association of dummy types with subprograms. */
9507 }