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1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2008, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License along with GCC; see the file COPYING3. If not see *
19 * <http://www.gnu.org/licenses/>. *
20 * *
21 * GNAT was originally developed by the GNAT team at New York University. *
22 * Extensive contributions were provided by Ada Core Technologies Inc. *
23 * *
24 ****************************************************************************/
56 #ifndef MAX_FIXED_MODE_SIZE
57 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
58 #endif
60 /* Convention_Stdcall should be processed in a specific way on Windows targets
61 only. The macro below is a helper to avoid having to check for a Windows
62 specific attribute throughout this unit. */
64 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
65 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
66 #else
67 #define Has_Stdcall_Convention(E) (0)
68 #endif
70 struct incomplete
71 {
73 tree old_type;
74 Entity_Id full_type;
75 };
77 /* These variables are used to defer recursively expanding incomplete types
78 while we are processing an array, a record or a subprogram type. */
82 /* This variable is used to delay expanding From_With_Type types until the
83 end of the spec. */
86 /* These variables are used to defer finalizing types. The element of the
87 list is the TYPE_DECL associated with the type. */
91 /* A hash table used to cache the result of annotate_value. */
125 /* Given GNAT_ENTITY, an entity in the incoming GNAT tree, return a
126 GCC type corresponding to that entity. GNAT_ENTITY is assumed to
127 refer to an Ada type. */
129 tree
131 {
132 tree gnu_decl;
134 /* The back end never attempts to annotate generic types */
138 /* Convert the ada entity type into a GCC TYPE_DECL node. */
142 }
143 \f
144 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
145 entity, this routine returns the equivalent GCC tree for that entity
146 (an ..._DECL node) and associates the ..._DECL node with the input GNAT
147 defining identifier.
149 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
150 initial value (in GCC tree form). This is optional for variables.
151 For renamed entities, GNU_EXPR gives the object being renamed.
153 DEFINITION is nonzero if this call is intended for a definition. This is
154 used for separate compilation where it necessary to know whether an
155 external declaration or a definition should be created if the GCC equivalent
156 was not created previously. The value of 1 is normally used for a nonzero
157 DEFINITION, but a value of 2 is used in special circumstances, defined in
158 the code. */
160 tree
162 {
164 tree gnu_entity_id;
166 /* Contains the gnu XXXX_DECL tree node which is equivalent to the input
167 GNAT tree. This node will be associated with the GNAT node by calling
168 the save_gnu_tree routine at the end of the `switch' statement. */
170 /* true if we have already saved gnu_decl as a gnat association. */
172 /* Nonzero if we incremented defer_incomplete_level. */
174 /* Nonzero if we incremented force_global. */
176 /* Nonzero if we should check to see if elaborated during processing. */
178 /* Nonzero if we made GNU_DECL and its type here. */
184 Entity_Id gnat_temp;
185 unsigned int esize
195 bool imported_p
199 /* Since a use of an Itype is a definition, process it as such if it
200 is not in a with'ed unit. */
205 {
206 /* Ensure that we are in a subprogram mentioned in the Scope
207 chain of this entity, our current scope is global,
208 or that we encountered a task or entry (where we can't currently
209 accurately check scoping). */
212 {
215 }
219 {
224 gnat_temp
236 && (current_function_decl
238 {
241 }
242 }
244 /* This abort means the entity "gnat_entity" has an incorrect scope,
245 i.e. that its scope does not correspond to the subprogram in which
246 it is declared */
248 }
250 /* If this is entity 0, something went badly wrong. */
253 /* If we've already processed this entity, return what we got last time.
254 If we are defining the node, we should not have already processed it.
255 In that case, we will abort below when we try to save a new GCC tree for
256 this object. We also need to handle the case of getting a dummy type
257 when a Full_View exists. */
261 {
268 {
274 }
277 }
279 /* If this is a numeric or enumeral type, or an access type, a nonzero
280 Esize must be specified unless it was specified by the programmer. */
289 /* Likewise, RM_Size must be specified for all discrete and fixed-point
290 types. */
294 /* Get the name of the entity and set up the line number and filename of
295 the original definition for use in any decl we make. */
299 /* If we get here, it means we have not yet done anything with this
300 entity. If we are not defining it here, it must be external,
301 otherwise we should have defined it already. */
308 /* For cases when we are not defining (i.e., we are referencing from
309 another compilation unit) Public entities, show we are at global level
310 for the purpose of computing scopes. Don't do this for components or
311 discriminants since the relevant test is whether or not the record is
312 being defined. But do this for Imported functions or procedures in
313 all cases. */
321 /* Handle any attributes directly attached to the entity. */
325 /* Machine_Attributes on types are expected to be propagated to subtypes.
326 The corresponding Gigi_Rep_Items are only attached to the first subtype
327 though, so we handle the propagation here. */
334 {
336 /* If this is a use of a deferred constant, get its full
337 declaration. */
339 {
344 }
346 /* If we have an external constant that we are not defining, get the
347 expression that is was defined to represent. We may throw that
348 expression away later if it is not a constant. Do not retrieve the
349 expression if it is an aggregate or allocator, because in complex
350 instantiation contexts it may not be expanded */
360 /* Ignore deferred constant definitions; they are processed fully in the
361 front-end. For deferred constant references get the full definition.
362 On the other hand, constants that are renamings are handled like
363 variable renamings. If No_Initialization is set, this is not a
364 deferred constant but a constant whose value is built manually. */
368 {
372 }
375 {
380 }
385 /* We used to special case VMS exceptions here to directly map them to
386 their associated condition code. Since this code had to be masked
387 dynamically to strip off the severity bits, this caused trouble in
388 the GCC/ZCX case because the "type" pointers we store in the tables
389 have to be static. We now don't special case here anymore, and let
390 the regular processing take place, which leaves us with a regular
391 exception data object for VMS exceptions too. The condition code
392 mapping is taken care of by the front end and the bitmasking by the
393 runtime library. */
398 {
399 /* The GNAT record where the component was defined. */
402 /* If the variable is an inherited record component (in the case of
403 extended record types), just return the inherited entity, which
404 must be a FIELD_DECL. Likewise for discriminants.
405 For discriminants of untagged records which have explicit
406 stored discriminants, return the entity for the corresponding
407 stored discriminant. Also use Original_Record_Component
408 if the record has a private extension. */
412 {
413 gnu_decl
418 }
420 /* If the enclosing record has explicit stored discriminants,
421 then it is an untagged record. If the Corresponding_Discriminant
422 is not empty then this must be a renamed discriminant and its
423 Original_Record_Component must point to the corresponding explicit
424 stored discriminant (i.e., we should have taken the previous
425 branch). */
429 {
430 /* A tagged record has no explicit stored discriminants. */
434 gnu_decl
439 }
443 {
448 }
450 /* If the enclosing record has explicit stored discriminants,
451 then it is an untagged record. If the Corresponding_Discriminant
452 is not empty then this must be a renamed discriminant and its
453 Original_Record_Component must point to the corresponding explicit
454 stored discriminant (i.e., we should have taken the first
455 branch). */
462 /* Otherwise, if we are not defining this and we have no GCC type
463 for the containing record, make one for it. Then we should
464 have made our own equivalent. */
466 {
467 /* ??? If this is in a record whose scope is a protected
468 type and we have an Original_Record_Component, use it.
469 This is a workaround for major problems in protected type
470 handling. */
477 {
478 gnu_decl
484 }
490 }
492 else
493 /* Here we have no GCC type and this is a reference rather than a
494 definition. This should never happen. Most likely the cause is a
495 reference before declaration in the gnat tree for gnat_entity. */
497 }
503 /* Simple variables, loop variables, Out parameters, and exceptions. */
504 object:
505 {
507 bool const_flag
519 tree gnu_object_size;
522 {
526 else
528 }
530 /* Get the type after elaborating the renamed object. */
533 /* For a debug renaming declaration, build a pure debug entity. */
535 {
536 rtx addr;
538 /* The (MEM (CONST (0))) pattern is prescribed by STABS. */
541 else
546 }
548 /* If this is a loop variable, its type should be the base type.
549 This is because the code for processing a loop determines whether
550 a normal loop end test can be done by comparing the bounds of the
551 loop against those of the base type, which is presumed to be the
552 size used for computation. But this is not correct when the size
553 of the subtype is smaller than the type. */
557 /* Reject non-renamed objects whose types are unconstrained arrays or
558 any object whose type is a dummy type or VOID_TYPE. */
564 {
567 force_global--;
569 }
571 /* If an alignment is specified, use it if valid. Note that
572 exceptions are objects but don't have alignments. We must do this
573 before we validate the size, since the alignment can affect the
574 size. */
576 {
582 }
584 /* If we are defining the object, see if it has a Size value and
585 validate it if so. If we are not defining the object and a Size
586 clause applies, simply retrieve the value. We don't want to ignore
587 the clause and it is expected to have been validated already. Then
588 get the new type, if any. */
597 {
598 gnu_type
604 }
606 /* If this object has self-referential size, it must be a record with
607 a default value. We are supposed to allocate an object of the
608 maximum size in this case unless it is a constant with an
609 initializing expression, in which case we can get the size from
610 that. Note that the resulting size may still be a variable, so
611 this may end up with an indirect allocation. */
614 {
616 {
619 {
620 /* If the initializing expression is itself a constant,
621 despite having a nominal type with self-referential
622 size, we can get the size directly from it. */
625 == RECORD_TYPE
626 && TYPE_IS_PADDING_P
630 || DECL_READONLY_ONCE_ELAB
633 else
634 gnu_size
636 }
637 else
639 }
640 /* We may have no GNU_EXPR because No_Initialization is
641 set even though there's an Expression. */
646 gnu_size
648 (Etype
650 else
651 {
654 }
655 }
657 /* If the size is zero bytes, make it one byte since some linkers have
658 trouble with zero-sized objects. If the object will have a
659 template, that will make it nonzero so don't bother. Also avoid
660 doing that for an object renaming or an object with an address
661 clause, as we would lose useful information on the view size
662 (e.g. for null array slices) and we are not allocating the object
663 here anyway. */
676 /* If this is an object with no specified size and alignment, and if
677 either it is atomic or we are not optimizing alignment for space
678 and it is a non-scalar variable, and the size of its type is a
679 constant, set the alignment to the smallest not less than the
680 size, or to the biggest meaningful one, whichever is smaller. */
689 {
690 /* No point in jumping through all the hoops needed in order
691 to support BIGGEST_ALIGNMENT if we don't really have to. */
693 ? BIGGEST_ALIGNMENT
699 else
702 /* But make sure not to under-align the object. */
706 /* And honor the minimum valid atomic alignment, if any. */
707 #ifdef MINIMUM_ATOMIC_ALIGNMENT
710 #endif
711 }
713 /* If the object is set to have atomic components, find the component
714 type and validate it.
716 ??? Note that we ignore Has_Volatile_Components on objects; it's
717 not at all clear what to do in that case. */
720 {
729 }
731 /* Now check if the type of the object allows atomic access. Note
732 that we must test the type, even if this object has size and
733 alignment to allow such access, because we will be going
734 inside the padded record to assign to the object. We could fix
735 this by always copying via an intermediate value, but it's not
736 clear it's worth the effort. */
740 /* If this is an aliased object with an unconstrained nominal subtype,
741 make a type that includes the template. */
745 {
746 tree gnu_fat
749 gnu_type
753 }
755 #ifdef MINIMUM_ATOMIC_ALIGNMENT
756 /* If the size is a constant and no alignment is specified, force
757 the alignment to be the minimum valid atomic alignment. The
758 restriction on constant size avoids problems with variable-size
759 temporaries; if the size is variable, there's no issue with
760 atomic access. Also don't do this for a constant, since it isn't
761 necessary and can interfere with constant replacement. Finally,
762 do not do it for Out parameters since that creates an
763 size inconsistency with In parameters. */
772 #endif
774 /* Make a new type with the desired size and alignment, if needed.
775 But do not take into account alignment promotions to compute the
776 size of the object. */
783 /* Make a volatile version of this object's type if we are to make
784 the object volatile. We also interpret 13.3(19) conservatively
785 and disallow any optimizations for an object covered by it. */
788 /* Exclude exported constants created by the compiler,
789 which should boil down to static dispatch tables and
790 make it possible to put them in read-only memory. */
799 /* If this is a renaming, avoid as much as possible to create a new
800 object. However, in several cases, creating it is required.
801 This processing needs to be applied to the raw expression so
802 as to make it more likely to rename the underlying object. */
804 {
807 /* If the renamed object had padding, strip off the reference
808 to the inner object and reset our type. */
811 == RECORD_TYPE
813 /* Strip useless conversions around the object. */
815 {
818 }
820 /* Case 1: If this is a constant renaming stemming from a function
821 call, treat it as a normal object whose initial value is what
822 is being renamed. RM 3.3 says that the result of evaluating a
823 function call is a constant object. As a consequence, it can
824 be the inner object of a constant renaming. In this case, the
825 renaming must be fully instantiated, i.e. it cannot be a mere
826 reference to (part of) an existing object. */
828 {
834 }
836 /* Otherwise, see if we can proceed with a stabilized version of
837 the renamed entity or if we need to make a new object. */
839 {
843 /* Case 2: If the renaming entity need not be materialized and
844 the renamed expression is something we can stabilize, use
845 that for the renaming. At the global level, we can only do
846 this if we know no SAVE_EXPRs need be made, because the
847 expression we return might be used in arbitrary conditional
848 branches so we must force the SAVE_EXPRs evaluation
849 immediately and this requires a function context. */
854 {
855 maybe_stable_expr
859 {
861 /* ??? No DECL_EXPR is created so we need to mark
862 the expression manually lest it is shared. */
868 }
870 /* The stabilization failed. Keep maybe_stable_expr
871 untouched here to let the pointer case below know
872 about that failure. */
873 }
875 /* Case 3: If this is a constant renaming and creating a
876 new object is allowed and cheap, treat it as a normal
877 object whose initial value is what is being renamed. */
879 ;
881 /* Case 4: Make this into a constant pointer to the object we
882 are to rename and attach the object to the pointer if it is
883 something we can stabilize.
885 From the proper scope, attached objects will be referenced
886 directly instead of indirectly via the pointer to avoid
887 subtle aliasing problems with non-addressable entities.
888 They have to be stable because we must not evaluate the
889 variables in the expression every time the renaming is used.
890 The pointer is called a "renaming" pointer in this case.
892 In the rare cases where we cannot stabilize the renamed
893 object, we just make a "bare" pointer, and the renamed
894 entity is always accessed indirectly through it. */
895 else
896 {
901 /* If the previous attempt at stabilizing failed, there
902 is no point in trying again and we reuse the result
903 without attaching it to the pointer. In this case it
904 will only be used as the initializing expression of
905 the pointer and thus needs no special treatment with
906 regard to multiple evaluations. */
908 ;
910 /* Otherwise, try to stabilize and attach the expression
911 to the pointer if the stabilization succeeds.
913 Note that this might introduce SAVE_EXPRs and we don't
914 check whether we're at the global level or not. This
915 is fine since we are building a pointer initializer and
916 neither the pointer nor the initializing expression can
917 be accessed before the pointer elaboration has taken
918 place in a correct program.
920 These SAVE_EXPRs will be evaluated at the right place
921 by either the evaluation of the initializer for the
922 non-global case or the elaboration code for the global
923 case, and will be attached to the elaboration procedure
924 in the latter case. */
925 else
926 {
927 maybe_stable_expr
933 /* Attaching is actually performed downstream, as soon
934 as we have a VAR_DECL for the pointer we make. */
935 }
937 gnu_expr
942 }
943 }
944 }
946 /* If this is an aliased object whose nominal subtype is unconstrained,
947 the object is a record that contains both the template and
948 the object. If there is an initializer, it will have already
949 been converted to the right type, but we need to create the
950 template if there is no initializer. */
954 /* Beware that padding might have been introduced
955 via maybe_pad_type above. */
958 == RECORD_TYPE
959 && TYPE_CONTAINS_TEMPLATE_P
962 {
963 tree template_field
968 gnu_expr
969 = gnat_build_constructor
971 tree_cons
975 NULL_TREE),
976 NULL_TREE));
977 }
979 /* Convert the expression to the type of the object except in the
980 case where the object's type is unconstrained or the object's type
981 is a padded record whose field is of self-referential size. In
982 the former case, converting will generate unnecessary evaluations
983 of the CONSTRUCTOR to compute the size and in the latter case, we
984 want to only copy the actual data. */
990 && (CONTAINS_PLACEHOLDER_P
994 /* If this is a pointer and it does not have an initializing
995 expression, initialize it to NULL, unless the object is
996 imported. */
1002 /* If we are defining the object and it has an Address clause we must
1003 get the address expression from the saved GCC tree for the
1004 object if the object has a Freeze_Node. Otherwise, we elaborate
1005 the address expression here since the front-end has guaranteed
1006 in that case that the elaboration has no effects. Note that
1007 only the latter mechanism is currently in use. */
1009 {
1010 tree gnu_address
1016 /* Ignore the size. It's either meaningless or was handled
1017 above. */
1019 /* Convert the type of the object to a reference type that can
1020 alias everything as per 13.3(19). */
1021 gnu_type
1027 /* If we don't have an initializing expression for the underlying
1028 variable, the initializing expression for the pointer is the
1029 specified address. Otherwise, we have to make a COMPOUND_EXPR
1030 to assign both the address and the initial value. */
1033 else
1034 gnu_expr
1036 build_binary_op
1039 gnu_address),
1040 gnu_expr),
1041 gnu_address);
1042 }
1044 /* If it has an address clause and we are not defining it, mark it
1045 as an indirect object. Likewise for Stdcall objects that are
1046 imported. */
1050 {
1051 /* Convert the type of the object to a reference type that can
1052 alias everything as per 13.3(19). */
1053 gnu_type
1058 /* No point in taking the address of an initializing expression
1059 that isn't going to be used. */
1062 }
1064 /* If we are at top level and this object is of variable size,
1065 make the actual type a hidden pointer to the real type and
1066 make the initializer be a memory allocation and initialization.
1067 Likewise for objects we aren't defining (presumed to be
1068 external references from other packages), but there we do
1069 not set up an initialization.
1071 If the object's size overflows, make an allocator too, so that
1072 Storage_Error gets raised. Note that we will never free
1073 such memory, so we presume it never will get allocated. */
1078 || (gnu_size
1082 {
1088 /* In case this was a aliased object whose nominal subtype is
1089 unconstrained, the pointer above will be a thin pointer and
1090 build_allocator will automatically make the template.
1092 If we have a template initializer only (that we made above),
1093 pretend there is none and rely on what build_allocator creates
1094 again anyway. Otherwise (if we have a full initializer), get
1095 the data part and feed that to build_allocator.
1097 If we are elaborating a mutable object, tell build_allocator to
1098 ignore a possibly simpler size from the initializer, if any, as
1099 we must allocate the maximum possible size in this case. */
1102 {
1107 {
1108 gnu_alloc_type
1115 else
1116 gnu_expr
1117 = build_component_ref
1121 }
1127 gnat_entity);
1131 }
1132 else
1133 {
1136 }
1137 }
1139 /* If this object would go into the stack and has an alignment larger
1140 than the largest stack alignment the back-end can honor, resort to
1141 a variable of "aligning type". */
1144 {
1145 /* Create the new variable. No need for extra room before the
1146 aligned field as this is in automatic storage. */
1147 tree gnu_new_type
1151 tree gnu_new_var
1156 /* Initialize the aligned field if we have an initializer. */
1158 add_stmt_with_node
1160 build_component_ref
1163 gnu_expr),
1164 gnat_entity);
1166 /* And setup this entity as a reference to the aligned field. */
1168 gnu_expr
1169 = build_unary_op
1177 }
1183 /* Convert the expression to the type of the object except in the
1184 case where the object's type is unconstrained or the object's type
1185 is a padded record whose field is of self-referential size. In
1186 the former case, converting will generate unnecessary evaluations
1187 of the CONSTRUCTOR to compute the size and in the latter case, we
1188 want to only copy the actual data. */
1194 && (CONTAINS_PLACEHOLDER_P
1198 /* If this name is external or there was a name specified, use it,
1199 unless this is a VMS exception object since this would conflict
1200 with the symbol we need to export in addition. Don't use the
1201 Interface_Name if there is an address clause (see CD30005). */
1210 /* If this is constant initialized to a static constant and the
1211 object has an aggregate type, force it to be statically
1212 allocated. */
1228 {
1231 {
1234 }
1235 }
1242 STACK_CHECK_MAX_VAR_SIZE))))
1247 gnat_entity);
1249 /* If this is a public constant or we're not optimizing and we're not
1250 making a VAR_DECL for it, make one just for export or debugger use.
1251 Likewise if the address is taken or if either the object or type is
1252 aliased. Make an external declaration for a reference, unless this
1253 is a Standard entity since there no real symbol at the object level
1254 for these. */
1262 {
1263 tree gnu_corr_var
1267 gnat_entity);
1270 }
1272 /* If this is declared in a block that contains a block with an
1273 exception handler, we must force this variable in memory to
1274 suppress an invalid optimization. */
1281 /* Back-annotate Alignment and Esize of the object if not already
1282 known, except for when the object is actually a pointer to the
1283 real object, since alignment and size of a pointer don't have
1284 anything to do with those of the designated object. Note that
1285 we pick the values of the type, not those of the object, to
1286 shield ourselves from low-level platform-dependent adjustments
1287 like alignment promotion. This is both consistent with all the
1288 treatment above, where alignment and size are set on the type of
1289 the object and not on the object directly, and makes it possible
1290 to support confirming representation clauses in all cases. */
1297 {
1300 gnu_object_size
1304 }
1305 }
1309 /* Return a TYPE_DECL for "void" that we previously made. */
1314 /* A special case, for the types Character and Wide_Character in
1315 Standard, we do not list all the literals. So if the literals
1316 are not specified, make this an unsigned type. */
1318 {
1322 /* Set the TYPE_STRING_FLAG for Ada Character and
1323 Wide_Character types. This is needed by the dwarf-2 debug writer to
1324 distinguish between unsigned integer types and character types. */
1327 }
1329 /* Normal case of non-character type, or non-Standard character type */
1330 {
1331 /* Here we have a list of enumeral constants in First_Literal.
1332 We make a CONST_DECL for each and build into GNU_LITERAL_LIST
1333 the list to be places into TYPE_FIELDS. Each node in the list
1334 is a TREE_LIST node whose TREE_VALUE is the literal name
1335 and whose TREE_PURPOSE is the value of the literal.
1337 Esize contains the number of bits needed to represent the enumeral
1338 type, Type_Low_Bound also points to the first literal and
1339 Type_High_Bound points to the last literal. */
1341 Entity_Id gnat_literal;
1346 else
1354 {
1356 gnu_type);
1357 tree gnu_literal
1365 }
1369 /* Note that the bounds are updated at the end of this function
1370 because to avoid an infinite recursion when we get the bounds of
1371 this type, since those bounds are objects of this type. */
1372 }
1378 /* For integer types, just make a signed type the appropriate number
1379 of bits. */
1384 /* For modular types, make the unsigned type of the proper number of
1385 bits and then set up the modulus, if required. */
1386 {
1388 tree gnu_modulus;
1394 /* Find the smallest mode at least ESIZE bits wide and make a class
1395 using that mode. */
1400 ;
1407 /* Get the modulus in this type. If it overflows, assume it is because
1408 it is equal to 2**Esize. Note that there is no overflow checking
1409 done on unsigned type, so we detect the overflow by looking for
1410 a modulus of zero, which is otherwise invalid. */
1414 {
1419 }
1421 /* If we have to set TYPE_PRECISION different from its natural value,
1422 make a subtype to do do. Likewise if there is a modulus and
1423 it is not one greater than TYPE_MAX_VALUE. */
1427 {
1445 }
1446 }
1455 /* For integral subtypes, we make a new INTEGER_TYPE. Note
1456 that we do not want to call build_range_type since we would
1457 like each subtype node to be distinct. This will be important
1458 when memory aliasing is implemented.
1460 The TREE_TYPE field of the INTEGER_TYPE we make points to the
1461 parent type; this fact is used by the arithmetic conversion
1462 functions.
1464 We elaborate the Ancestor_Subtype if it is not in the current
1465 unit and one of our bounds is non-static. We do this to ensure
1466 consistent naming in the case where several subtypes share the same
1467 bounds by always elaborating the first such subtype first, thus
1468 using its name. */
1481 {
1484 }
1492 gnat_entity,
1499 gnat_entity,
1503 /* One of the above calls might have caused us to be elaborated,
1504 so don't blow up if so. */
1506 {
1509 }
1514 /* This should be an unsigned type if the lower bound is constant
1515 and non-negative or if the base type is unsigned; a signed type
1516 otherwise. */
1526 /* Inherit our alias set from what we're a subtype of. Subtypes
1527 are not different types and a pointer can designate any instance
1528 within a subtype hierarchy. */
1531 /* If the type we are dealing with is to represent a packed array,
1532 we need to have the bits left justified on big-endian targets
1533 and right justified on little-endian targets. We also need to
1534 ensure that when the value is read (e.g. for comparison of two
1535 such values), we only get the good bits, since the unused bits
1536 are uninitialized. Both goals are accomplished by wrapping the
1537 modular value in an enclosing struct. */
1540 {
1542 tree gnu_field;
1549 /* Propagate the alignment of the modular type to the record.
1550 This means that bitpacked arrays have "ceil" alignment for
1551 their size, which may seem counter-intuitive but makes it
1552 possible to easily overlay them on modular types. */
1556 /* Create a stripped-down declaration of the original type, mainly
1557 for debugging. */
1561 /* Don't notify the field as "addressable", since we won't be taking
1562 it's address and it would prevent create_field_decl from making a
1563 bitfield. */
1572 }
1574 /* If the type we are dealing with has got a smaller alignment than the
1575 natural one, we need to wrap it up in a record type and under-align
1576 the latter. We reuse the padding machinery for this purpose. */
1581 {
1583 tree gnu_field;
1591 /* Create a stripped-down declaration of the original type, mainly
1592 for debugging. */
1596 /* Don't notify the field as "addressable", since we won't be taking
1597 it's address and it would prevent create_field_decl from making a
1598 bitfield. */
1607 }
1609 /* Otherwise reset the alignment lest we computed it above. */
1610 else
1616 /* If this is a VAX floating-point type, use an integer of the proper
1617 size. All the operations will be handled with ASM statements. */
1619 {
1624 sizetype));
1626 }
1628 /* The type of the Low and High bounds can be our type if this is
1629 a type from Standard, so set them at the end of the function. */
1637 {
1640 }
1642 {
1669 /* One of the above calls might have caused us to be elaborated,
1670 so don't blow up if so. */
1672 {
1675 }
1679 /* Inherit our alias set from what we're a subtype of, as for
1680 integer subtypes. */
1682 }
1685 /* Array and String Types and Subtypes
1687 Unconstrained array types are represented by E_Array_Type and
1688 constrained array types are represented by E_Array_Subtype. There
1689 are no actual objects of an unconstrained array type; all we have
1690 are pointers to that type.
1692 The following fields are defined on array types and subtypes:
1694 Component_Type Component type of the array.
1695 Number_Dimensions Number of dimensions (an int).
1696 First_Index Type of first index. */
1700 {
1706 int firstdim
1708 int nextdim
1715 tree gnu_max_size_unit;
1716 Entity_Id gnat_ind_subtype;
1717 Entity_Id gnat_ind_base_subtype;
1718 tree gnu_template_reference;
1719 tree tem;
1724 /* Make a node for the array. If we are not defining the array
1725 suppress expanding incomplete types. */
1731 /* Build the fat pointer type. Use a "void *" object instead of
1732 a pointer to the array type since we don't have the array type
1733 yet (it will reference the fat pointer via the bounds). */
1736 ptr_void_type_node,
1739 gnu_ptr_template,
1742 /* Make sure we can put this into a register. */
1745 /* Do not finalize this record type since the types of its fields
1746 are still incomplete at this point. */
1750 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1751 is the fat pointer. This will be used to access the individual
1752 fields once we build them. */
1756 gnu_template_reference
1760 /* Now create the GCC type for each index and add the fields for
1761 that index to the template. */
1763 gnat_ind_base_subtype
1769 {
1771 tree gnu_ind_subtype
1773 tree gnu_base_subtype
1775 tree gnu_base_min
1777 tree gnu_base_max
1781 /* Make the FIELD_DECLs for the minimum and maximum of this
1782 type and then make extractions of that field from the
1783 template. */
1786 gnu_ind_subtype,
1790 gnu_ind_subtype,
1799 /* We can't use build_component_ref here since the template
1800 type isn't complete yet. */
1803 NULL_TREE);
1806 NULL_TREE);
1809 /* Make a range type with the new ranges, but using
1810 the Ada subtype. Then we convert to sizetype. */
1816 gnat_entity);
1817 /* Update the maximum size of the array, in elements. */
1818 gnu_max_size
1822 gnu_base_min)));
1826 }
1829 gnu_template_fields
1832 /* Install all the fields into the template. */
1836 /* Now make the array of arrays and update the pointer to the array
1837 in the fat pointer. Note that it is the first field. */
1840 /* Try to get a smaller form of the component if needed. */
1853 /* Get and validate any specified Component_Size, but if Packed,
1854 ignore it since the front end will have taken care of it. */
1855 gnu_comp_size
1857 gnat_entity,
1862 /* If the component type is a RECORD_TYPE that has a self-referential
1863 size, use the maxium size. */
1869 {
1870 tree orig_tem;
1875 /* If a padding record was made, declare it now since it will
1876 never be declared otherwise. This is necessary to ensure
1877 that its subtrees are properly marked. */
1880 gnat_entity);
1881 }
1887 /* If Component_Size is not already specified, annotate it with the
1888 size of the component. */
1898 gnu_max_size),
1902 {
1907 }
1909 /* If an alignment is specified, use it if valid. But ignore it for
1910 types that represent the unpacked base type for packed arrays. If
1911 the alignment was requested with an explicit user alignment clause,
1912 state so. */
1915 {
1922 }
1928 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
1929 corresponding fat pointer. */
1936 /* If the maximum size doesn't overflow, use it. */
1951 /* Give the fat pointer type a name. */
1956 /* Create the type to be used as what a thin pointer designates: an
1957 record type for the object and its template with the field offsets
1958 shifted to have the template at a negative offset. */
1966 /* Give the thin pointer type a name. */
1970 gnat_entity);
1971 }
1977 /* This is the actual data type for array variables. Multidimensional
1978 arrays are implemented in the gnu tree as arrays of arrays. Note
1979 that for the moment arrays which have sparse enumeration subtypes as
1980 index components create sparse arrays, which is obviously space
1981 inefficient but so much easier to code for now.
1983 Also note that the subtype never refers to the unconstrained
1984 array type, which is somewhat at variance with Ada semantics.
1986 First check to see if this is simply a renaming of the array
1987 type. If so, the result is the array type. */
1992 else
1993 {
1996 int first_dim
1999 int next_dim
2001 Entity_Id gnat_ind_subtype;
2002 Entity_Id gnat_ind_base_subtype;
2007 tree gnu_max_size_unit;
2011 /* First create the gnu types for each index. Create types for
2012 debugging information to point to the index types if the
2013 are not integer types, have variable bounds, or are
2014 wider than sizetype. */
2017 gnat_ind_base_subtype
2023 {
2024 tree gnu_index_subtype
2026 tree gnu_min
2028 tree gnu_max
2030 tree gnu_base_subtype
2032 tree gnu_base_min
2034 tree gnu_base_max
2037 tree gnu_base_base_min
2039 tree gnu_base_base_max
2041 tree gnu_high;
2042 tree gnu_this_max;
2044 /* If the minimum and maximum values both overflow in
2045 SIZETYPE, but the difference in the original type
2046 does not overflow in SIZETYPE, ignore the overflow
2047 indications. */
2055 && (!TREE_OVERFLOW
2059 {
2062 }
2064 /* Similarly, if the range is null, use bounds of 1..0 for
2065 the sizetype bounds. */
2077 /* Now compute the size of this bound. We need to provide
2078 GCC with an upper bound to use but have to deal with the
2079 "superflat" case. There are three ways to do this. If we
2080 can prove that the array can never be superflat, we can
2081 just use the high bound of the index subtype. If we can
2082 prove that the low bound minus one can't overflow, we
2083 can do this as MAX (hb, lb - 1). Otherwise, we have to use
2084 the expression hb >= lb ? hb : lb - 1. */
2087 /* See if the base array type is already flat. If it is, we
2088 are probably compiling an ACVC test, but it will cause the
2089 code below to malfunction if we don't handle it specially. */
2097 /* If gnu_high is now an integer which overflowed, the array
2098 cannot be superflat. */
2105 else
2106 gnu_high
2107 = build_cond_expr
2114 gnat_entity);
2116 /* Also compute the maximum size of the array. Here we
2117 see if any constraint on the index type of the base type
2118 can be used in the case of self-referential bound on
2119 the index type of the subtype. We look for a non-"infinite"
2120 and non-self-referential bound from any type involved and
2121 handle each bound separately. */
2150 gnu_this_max
2154 gnu_base_min)),
2155 size_zero_node);
2161 gnu_max_size
2175 }
2177 /* Then flatten: create the array of arrays. For an array type
2178 used to implement a packed array, get the component type from
2179 the original array type since the representation clauses that
2180 can affect it are on the latter. */
2183 {
2188 /* One of the above calls might have caused us to be elaborated,
2189 so don't blow up if so. */
2191 {
2194 }
2195 }
2196 else
2197 {
2200 /* One of the above calls might have caused us to be elaborated,
2201 so don't blow up if so. */
2203 {
2206 }
2208 /* Try to get a smaller form of the component if needed. */
2218 /* Get and validate any specified Component_Size, but if Packed,
2219 ignore it since the front end will have taken care of it. */
2220 gnu_comp_size
2222 gnat_entity,
2227 /* If the component type is a RECORD_TYPE that has a
2228 self-referential size, use the maxium size. */
2235 {
2236 tree orig_gnu_type;
2237 gnu_type
2243 /* If a padding record was made, declare it now since it
2244 will never be declared otherwise. This is necessary
2245 to ensure that its subtrees are properly marked. */
2249 }
2255 }
2264 {
2269 }
2271 /* If we are at file level and this is a multi-dimensional array, we
2272 need to make a variable corresponding to the stride of the
2273 inner dimensions. */
2275 {
2277 tree gnu_arr_type;
2283 {
2291 /* ??? For now, store the size as a multiple of the
2292 alignment of the element type in bytes so that we
2293 can see the alignment from the tree. */
2295 = build_binary_op
2297 elaborate_expression_1
2307 /* ??? create_type_decl is not invoked on the inner types so
2308 the MULT_EXPR node built above will never be marked. */
2310 }
2311 }
2313 /* If we need to write out a record type giving the names of
2314 the bounds, do it now. */
2316 {
2319 tree gnu_field;
2325 {
2326 tree gnu_type_name
2333 integer_type_node,
2334 gnu_bound_rec_type,
2338 }
2342 }
2350 /* If our size depends on a placeholder and the maximum size doesn't
2351 overflow, use it. */
2358 {
2364 }
2366 /* Set our alias set to that of our base type. This gives all
2367 array subtypes the same alias set. */
2369 }
2371 /* If this is a packed type, make this type the same as the packed
2372 array type, but do some adjusting in the type first. */
2375 {
2376 Entity_Id gnat_index;
2377 tree gnu_inner_type;
2379 /* First finish the type we had been making so that we output
2380 debugging information for it */
2381 gnu_type
2384 | (TYPE_QUAL_VOLATILE
2392 /* Save it as our equivalent in case the call below elaborates
2393 this type again. */
2408 /* We need to point the type we just made to our index type so
2409 the actual bounds can be put into a template. */
2415 {
2417 {
2418 /* The TYPE_ACTUAL_BOUNDS field is also used for the modulus.
2419 If it is, we need to make another type. */
2421 {
2422 tree gnu_subtype;
2439 }
2442 }
2448 SET_TYPE_ACTUAL_BOUNDS
2455 SET_TYPE_ACTUAL_BOUNDS
2462 }
2463 }
2465 /* Abort if packed array with no packed array type field set. */
2466 else
2472 /* Create the type for a string literal. */
2473 {
2474 Entity_Id gnat_full_type
2479 tree gnu_string_array_type
2481 tree gnu_string_index_type
2484 tree gnu_lower_bound
2489 tree gnu_upper_bound
2491 gnu_lower_bound,
2493 tree gnu_range_type
2496 tree gnu_index_type
2503 gnu_type
2505 gnu_index_type);
2507 }
2510 /* Record Types and Subtypes
2512 The following fields are defined on record types:
2514 Has_Discriminants True if the record has discriminants
2515 First_Discriminant Points to head of list of discriminants
2516 First_Entity Points to head of list of fields
2517 Is_Tagged_Type True if the record is tagged
2519 Implementation of Ada records and discriminated records:
2521 A record type definition is transformed into the equivalent of a C
2522 struct definition. The fields that are the discriminants which are
2523 found in the Full_Type_Declaration node and the elements of the
2524 Component_List found in the Record_Type_Definition node. The
2525 Component_List can be a recursive structure since each Variant of
2526 the Variant_Part of the Component_List has a Component_List.
2528 Processing of a record type definition comprises starting the list of
2529 field declarations here from the discriminants and the calling the
2530 function components_to_record to add the rest of the fields from the
2531 component list and return the gnu type node. The function
2532 components_to_record will call itself recursively as it traverses
2533 the tree. */
2537 {
2538 gnu_type
2539 = build_complex_type
2540 (get_unpadded_type
2543 (Component_List
2544 (Type_Definition
2548 }
2550 {
2553 Entity_Id gnat_field;
2554 tree gnu_field;
2556 tree gnu_get_parent;
2557 /* Set PACKED in keeping with gnat_to_gnu_field. */
2558 int packed
2570 bool is_extension
2574 /* See if all fields have a rep clause. Stop when we find one
2575 that doesn't. */
2584 /* If this is a record extension, go a level further to find the
2585 record definition. Also, verify we have a Parent_Subtype. */
2587 {
2594 }
2596 /* Make a node for the record. If we are not defining the record,
2597 suppress expanding incomplete types. */
2605 /* If both a size and rep clause was specified, put the size in
2606 the record type now so that it can get the proper mode. */
2610 /* Always set the alignment here so that it can be used to
2611 set the mode, if it is making the alignment stricter. If
2612 it is invalid, it will be checked again below. If this is to
2613 be Atomic, choose a default alignment of a word unless we know
2614 the size and it's smaller. */
2621 /* If a type needs strict alignment, the minimum size will be the
2622 type size instead of the RM size (see validate_size). Cap the
2623 alignment, lest it causes this type size to become too large. */
2626 {
2631 }
2632 else
2635 /* If we have a Parent_Subtype, make a field for the parent. If
2636 this record has rep clauses, force the position to zero. */
2638 {
2640 tree gnu_parent;
2642 /* A major complexity here is that the parent subtype will
2643 reference our discriminants in its Discriminant_Constraint
2644 list. But those must reference the parent component of this
2645 record which is of the parent subtype we have not built yet!
2646 To break the circle we first build a dummy COMPONENT_REF which
2647 represents the "get to the parent" operation and initialize
2648 each of those discriminants to a COMPONENT_REF of the above
2649 dummy parent referencing the corresponding discriminant of the
2650 base type of the parent subtype. */
2654 void_type_node),
2655 NULL_TREE);
2662 save_gnu_tree
2666 gnu_get_parent,
2669 NULL_TREE),
2672 /* Then we build the parent subtype. */
2675 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
2676 initially built. The discriminants must reference the fields
2677 of the parent subtype and not those of its base type for the
2678 placeholder machinery to properly work. */
2684 {
2694 }
2696 /* The "get to the parent" COMPONENT_REF must be given its
2697 proper type... */
2700 /* ...and reference the _parent field of this record. */
2701 gnu_field_list
2709 }
2711 /* Make the fields for the discriminants and put them into the record
2712 unless it's an Unchecked_Union. */
2717 {
2718 /* If this is a record extension and this discriminant
2719 is the renaming of another discriminant, we've already
2720 handled the discriminant above. */
2725 gnu_field
2728 /* Make an expression using a PLACEHOLDER_EXPR from the
2729 FIELD_DECL node just created and link that with the
2730 corresponding GNAT defining identifier. Then add to the
2731 list of fields. */
2740 {
2743 }
2744 }
2746 /* Put the discriminants into the record (backwards), so we can
2747 know the appropriate discriminant to use for the names of the
2748 variants. */
2751 /* Add the listed fields into the record and finish it up. */
2757 /* We used to remove the associations of the discriminants and
2758 _Parent for validity checking, but we may need them if there's
2759 Freeze_Node for a subtype used in this record. */
2763 /* If it is a tagged record force the type to BLKmode to insure
2764 that these objects will always be placed in memory. Do the
2765 same thing for limited record types. */
2769 /* If this is a derived type, we must make the alias set of this type
2770 the same as that of the type we are derived from. We assume here
2771 that the other type is already frozen. */
2777 /* Fill in locations of fields. */
2780 /* If there are any entities in the chain corresponding to
2781 components that we did not elaborate, ensure we elaborate their
2782 types if they are Itypes. */
2790 }
2794 /* If an equivalent type is present, that is what we should use.
2795 Otherwise, fall through to handle this like a record subtype
2796 since it may have constraints. */
2798 {
2802 }
2804 /* ... fall through ... */
2808 /* If Cloned_Subtype is Present it means this record subtype has
2809 identical layout to that type or subtype and we should use
2810 that GCC type for this one. The front end guarantees that
2811 the component list is shared. */
2813 {
2817 }
2819 /* Otherwise, first ensure the base type is elaborated. Then, if we are
2820 changing the type, make a new type with each field having the
2821 type of the field in the new subtype but having the position
2822 computed by transforming every discriminant reference according
2823 to the constraints. We don't see any difference between
2824 private and nonprivate type here since derivations from types should
2825 have been deferred until the completion of the private type. */
2826 else
2827 {
2829 tree gnu_base_type;
2830 tree gnu_orig_type;
2835 /* Get the base type initially for its alignment and sizes. But
2836 if it is a padded type, we do all the other work with the
2837 unpadded type. */
2843 else
2847 {
2850 }
2852 /* When the type has discriminants, and these discriminants
2853 affect the shape of what it built, factor them in.
2855 If we are making a subtype of an Unchecked_Union (must be an
2856 Itype), just return the type.
2858 We can't just use Is_Constrained because private subtypes without
2859 discriminants of full types with discriminants with default
2860 expressions are Is_Constrained but aren't constrained! */
2868 {
2869 Entity_Id gnat_field;
2871 tree gnu_pos_list
2874 BIGGEST_ALIGNMENT);
2875 tree gnu_subst_list
2877 definition);
2878 tree gnu_temp;
2894 {
2895 tree gnu_old_field
2898 tree gnu_offset
2900 gnu_pos_list));
2903 tree gnu_field_type
2907 unsigned int offset_align
2910 tree gnu_field;
2912 /* If there was a component clause, the field types must be
2913 the same for the type and subtype, so copy the data from
2914 the old field to avoid recomputation here. Also if the
2915 field is justified modular and the optimization in
2916 gnat_to_gnu_field was applied. */
2923 {
2926 }
2928 /* If the old field was packed and of constant size, we
2929 have to get the old size here, as it might differ from
2930 what the Etype conveys and the latter might overlap
2931 onto the following field. Try to arrange the type for
2932 possible better packing along the way. */
2936 {
2941 gnu_field_type
2943 }
2952 /* If the size is now a constant, we can set it as the
2953 size of the field when we make it. Otherwise, we need
2954 to deal with it specially. */
2958 gnu_field
2959 = create_field_decl
2965 {
2974 bitsize_unit_node));
2976 }
2980 SET_DECL_ORIGINAL_FIELD
2991 }
2993 /* Now go through the entities again looking for Itypes that
2994 we have not elaborated but should (e.g., Etypes of fields
2995 that have Original_Components). */
3003 /* Do not finalize it since we're going to modify it below. */
3007 /* Now set the size, alignment and alias set of the new type to
3008 match that of the old one, doing any substitutions, as
3009 above. */
3035 SET_TYPE_ADA_SIZE
3040 /* Reapply variable_size since we have changed the sizes. */
3045 /* Recompute the mode of this record type now that we know its
3046 actual size. */
3049 /* Fill in locations of fields. */
3052 /* We've built a new type, make an XVS type to show what this
3053 is a subtype of. Some debuggers require the XVS type to be
3054 output first, so do it in that order. */
3056 {
3067 integer_type_node,
3068 gnu_subtype_marker,
3072 }
3074 /* Now we can finalize it. */
3076 }
3078 /* Otherwise, go down all the components in the new type and
3079 make them equivalent to those in the base type. */
3080 else
3087 gnat_to_gnu_field_decl
3089 }
3093 /* Use the special descriptor type for dispatch tables if needed,
3094 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3095 Note that we are only required to do so for static tables in
3096 order to be compatible with the C++ ABI, but Ada 2005 allows
3097 to extend library level tagged types at the local level so
3098 we do it in the non-static case as well. */
3101 {
3105 }
3107 /* ... fall through ... */
3110 /* If we are not defining this entity, and we have incomplete
3111 entities being processed above us, make a dummy type and
3112 fill it in later. */
3114 {
3118 gnu_type
3119 = build_pointer_type
3134 }
3136 /* ... fall through ... */
3143 {
3146 bool is_from_limited_with
3150 /* Get the "full view" of this entity. If this is an incomplete
3151 entity from a limited with, treat its non-limited view as the full
3152 view. Otherwise, if this is an incomplete or private type, use the
3153 full view. In the former case, we might point to a private type,
3154 in which case, we need its full view. Also, we want to look at the
3155 actual type used for the representation, so this takes a total of
3156 three steps. */
3157 Entity_Id gnat_desig_full_direct_first
3161 Entity_Id gnat_desig_full_direct
3162 = ((is_from_limited_with
3167 Entity_Id gnat_desig_full
3170 /* This the type actually used to represent the designated type,
3171 either gnat_desig_full or gnat_desig_equiv. */
3172 Entity_Id gnat_desig_rep;
3174 /* Nonzero if this is a pointer to an unconstrained array. */
3177 /* We want to know if we'll be seeing the freeze node for any
3178 incomplete type we may be pointing to. */
3179 bool in_main_unit
3184 /* Nonzero if we make a dummy type here. */
3186 /* Nonzero if the dummy is a fat pointer. */
3194 /* If either the designated type or its full view is an unconstrained
3195 array subtype, replace it with the type it's a subtype of. This
3196 avoids problems with multiple copies of unconstrained array types.
3197 Likewise, if the designated type is a subtype of an incomplete
3198 record type, use the parent type to avoid order of elaboration
3199 issues. This can lose some code efficiency, but there is no
3200 alternative. */
3211 /* Now set the type that actually marks the representation of
3212 the designated type and also flag whether we have a unconstrained
3213 array. */
3215 is_unconstrained_array
3219 /* If we are pointing to an incomplete type whose completion is an
3220 unconstrained array, make a fat pointer type. The two types in our
3221 fields will be pointers to dummy nodes and will be replaced in
3222 update_pointer_to. Similarly, if the type itself is a dummy type or
3223 an unconstrained array. Also make a dummy TYPE_OBJECT_RECORD_TYPE
3224 in case we have any thin pointers to it. */
3235 {
3236 tree gnu_old
3240 tree fields;
3242 /* Show the dummy we get will be a fat pointer. */
3245 /* If the call above got something that has a pointer, that
3246 pointer is our type. This could have happened either
3247 because the type was elaborated or because somebody
3248 else executed the code below. */
3251 {
3272 fields
3274 create_field_decl
3276 gnu_ptr_array,
3279 gnu_ptr_template,
3282 /* Make sure we can place this into a register. */
3287 /* Do not finalize this record type since the types of
3288 its fields are incomplete. */
3296 }
3297 }
3299 /* If we already know what the full type is, use it. */
3304 /* Get the type of the thing we are to point to and build a pointer
3305 to it. If it is a reference to an incomplete or private type with a
3306 full view that is a record, make a dummy type node and get the
3307 actual type later when we have verified it is safe. */
3313 /* Likewise if we are pointing to a record or array and we
3314 are to defer elaborating incomplete types. We do this
3315 since this access type may be the full view of some
3316 private type. Note that the unconstrained array case is
3317 handled above. */
3323 /* If this is a reference from a limited_with type back to our
3324 main unit and there's a Freeze_Node for it, either we have
3325 already processed the declaration and made the dummy type,
3326 in which case we just reuse the latter, or we have not yet,
3327 in which case we make the dummy type and it will be reused
3328 when the declaration is processed. In both cases, the
3329 pointer eventually created below will be automatically
3330 adjusted when the Freeze_Node is processed. Note that the
3331 unconstrained array case is handled above. */
3334 {
3337 }
3339 /* Otherwise handle the case of a pointer to itself. */
3341 {
3342 gnu_type
3346 }
3348 /* If expansion is disabled, the equivalent type of a concurrent
3349 type is absent, so build a dummy pointer type. */
3353 /* Finally, handle the straightforward case where we can just
3354 elaborate our designated type and point to it. */
3355 else
3358 /* It is possible that a call to gnat_to_gnu_type above resolved our
3359 type. If so, just return it. */
3361 {
3364 }
3366 /* If we have a GCC type for the designated type, possibly modify it
3367 if we are pointing only to constant objects and then make a pointer
3368 to it. Don't do this for unconstrained arrays. */
3370 {
3373 {
3374 gnu_desig_type
3375 = build_qualified_type
3379 /* Some extra processing is required if we are building a
3380 pointer to an incomplete type (in the GCC sense). We might
3381 have such a type if we just made a dummy, or directly out
3382 of the call to gnat_to_gnu_type above if we are processing
3383 an access type for a record component designating the
3384 record type itself. */
3386 {
3387 /* We must ensure that the pointer to variant we make will
3388 be processed by update_pointer_to when the initial type
3389 is completed. Pretend we made a dummy and let further
3390 processing act as usual. */
3393 /* We must ensure that update_pointer_to will not retrieve
3394 the dummy variant when building a properly qualified
3395 version of the complete type. We take advantage of the
3396 fact that get_qualified_type is requiring TYPE_NAMEs to
3397 match to influence build_qualified_type and then also
3398 update_pointer_to here. */
3401 }
3402 }
3404 gnu_type
3407 }
3409 /* If we are not defining this object and we made a dummy pointer,
3410 save our current definition, evaluate the actual type, and replace
3411 the tentative type we made with the actual one. If we are to defer
3412 actually looking up the actual type, make an entry in the
3413 deferred list. If this is from a limited with, we have to defer
3414 to the end of the current spec in two cases: first if the
3415 designated type is in the current unit and second if the access
3416 type is. */
3418 {
3419 tree gnu_old_type
3425 gnu_type
3426 = build_pointer_type
3427 (TYPE_OBJECT_RECORD_TYPE
3439 && ! (is_from_limited_with
3440 && (in_main_unit
3445 /* Note that the call to gnat_to_gnu_type here might have
3446 updated gnu_old_type directly, in which case it is not a
3447 dummy type any more when we get into update_pointer_to.
3449 This may happen for instance when the designated type is a
3450 record type, because their elaboration starts with an
3451 initial node from make_dummy_type, which may yield the same
3452 node as the one we got.
3454 Besides, variants of this non-dummy type might have been
3455 created along the way. update_pointer_to is expected to
3456 properly take care of those situations. */
3457 else
3458 {
3463 = (is_from_limited_with
3464 && (in_main_unit
3472 }
3473 }
3474 }
3481 else
3482 {
3483 /* The runtime representation is the equivalent type. */
3486 }
3499 /* We treat this as identical to its base type; any constraint is
3500 meaningful only to the front end.
3502 The designated type must be elaborated as well, if it does
3503 not have its own freeze node. Designated (sub)types created
3504 for constrained components of records with discriminants are
3505 not frozen by the front end and thus not elaborated by gigi,
3506 because their use may appear before the base type is frozen,
3507 and because it is not clear that they are needed anywhere in
3508 Gigi. With the current model, there is no correct place where
3509 they could be elaborated. */
3516 {
3517 /* If we are not defining this entity, and we have incomplete
3518 entities being processed above us, make a dummy type and
3519 elaborate it later. */
3521 {
3524 tree gnu_ptr_type
3525 = build_pointer_type
3532 }
3535 Incomplete_Or_Private_Kind))
3538 }
3543 /* Subprogram Entities
3545 The following access functions are defined for subprograms (functions
3546 or procedures):
3548 First_Formal The first formal parameter.
3549 Is_Imported Indicates that the subprogram has appeared in
3550 an INTERFACE or IMPORT pragma. For now we
3551 assume that the external language is C.
3552 Is_Exported Likewise but for an EXPORT pragma.
3553 Is_Inlined True if the subprogram is to be inlined.
3555 In addition for function subprograms we have:
3557 Etype Return type of the function.
3559 Each parameter is first checked by calling must_pass_by_ref on its
3560 type to determine if it is passed by reference. For parameters which
3561 are copied in, if they are Ada In Out or Out parameters, their return
3562 value becomes part of a record which becomes the return type of the
3563 function (C function - note that this applies only to Ada procedures
3564 so there is no Ada return type). Additional code to store back the
3565 parameters will be generated on the caller side. This transformation
3566 is done here, not in the front-end.
3568 The intended result of the transformation can be seen from the
3569 equivalent source rewritings that follow:
3571 struct temp {int a,b};
3572 procedure P (A,B: In Out ...) is temp P (int A,B)
3573 begin {
3574 .. ..
3575 end P; return {A,B};
3576 }
3578 temp t;
3579 P(X,Y); t = P(X,Y);
3580 X = t.a , Y = t.b;
3582 For subprogram types we need to perform mainly the same conversions to
3583 GCC form that are needed for procedures and function declarations. The
3584 only difference is that at the end, we make a type declaration instead
3585 of a function declaration. */
3590 {
3591 /* The first GCC parameter declaration (a PARM_DECL node). The
3592 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3593 actually is the head of this parameter list. */
3595 /* Likewise for the stub associated with an exported procedure. */
3597 /* The type returned by a function. If the subprogram is a procedure
3598 this type should be void_type_node. */
3600 /* List of fields in return type of procedure with copy-in copy-out
3601 parameters. */
3603 /* Non-null for subprograms containing parameters passed by copy-in
3604 copy-out (Ada In Out or Out parameters not passed by reference),
3605 in which case it is the list of nodes used to specify the values of
3606 the in out/out parameters that are returned as a record upon
3607 procedure return. The TREE_PURPOSE of an element of this list is
3608 a field of the record and the TREE_VALUE is the PARM_DECL
3609 corresponding to that field. This list will be saved in the
3610 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3612 /* If an import pragma asks to map this subprogram to a GCC builtin,
3613 this is the builtin DECL node. */
3615 /* For the stub associated with an exported procedure. */
3618 Entity_Id gnat_param;
3621 bool extern_flag
3633 /* A parameter may refer to this type, so defer completion
3634 of any incomplete types. */
3637 /* If the subprogram has an alias, it is probably inherited, so
3638 we can use the original one. If the original "subprogram"
3639 is actually an enumeration literal, it may be the first use
3640 of its type, so we must elaborate that type now. */
3642 {
3649 /* Elaborate any Itypes in the parameters of this entity. */
3657 }
3659 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3660 corresponding DECL node.
3662 We still want the parameter associations to take place because the
3663 proper generation of calls depends on it (a GNAT parameter without
3664 a corresponding GCC tree has a very specific meaning), so we don't
3665 just break here. */
3669 /* ??? What if we don't find the builtin node above ? warn ? err ?
3670 In the current state we neither warn nor err, and calls will just
3671 be handled as for regular subprograms. */
3676 /* If this function returns by reference, make the actual
3677 return type of this function the pointer and mark the decl. */
3679 {
3682 }
3684 /* If the Mechanism is By_Reference, ensure the return type uses
3685 the machine's by-reference mechanism, which may not the same
3686 as above (e.g., it might be by passing a fake parameter). */
3689 {
3692 /* We expect this bit to be reset by gigi shortly, so can avoid a
3693 type node copy here. This actually also prevents troubles with
3694 the generation of debug information for the function, because
3695 we might have issued such info for this type already, and would
3696 be attaching a distinct type node to the function if we made a
3697 copy here. */
3698 }
3700 /* If we are supposed to return an unconstrained array,
3701 actually return a fat pointer and make a note of that. Return
3702 a pointer to an unconstrained record of variable size. */
3704 {
3707 }
3709 /* If the type requires a transient scope, the result is allocated
3710 on the secondary stack, so the result type of the function is
3711 just a pointer. */
3713 {
3716 }
3718 /* If the type is a padded type and the underlying type would not
3719 be passed by reference or this function has a foreign convention,
3720 return the underlying type. */
3728 /* If the return type has a non-constant size, we convert the function
3729 into a procedure and its caller will pass a pointer to an object as
3730 the first parameter when we call the function. This can happen for
3731 an unconstrained type with a maximum size or a constrained type with
3732 a size not known at compile time. */
3735 {
3737 gnu_param_list
3742 }
3744 /* If the return type has a size that overflows, we cannot have
3745 a function that returns that type. This usage doesn't make
3746 sense anyway, so give an error here. */
3750 {
3752 gnat_entity);
3758 }
3760 /* Look at all our parameters and get the type of
3761 each. While doing this, build a copy-out structure if
3762 we need one. */
3764 /* Loop over the parameters and get their associated GCC tree.
3765 While doing this, build a copy-out structure if we need one. */
3769 {
3776 /* Builtins are expanded inline and there is no real call sequence
3777 involved. So the type expected by the underlying expander is
3778 always the type of each argument "as is". */
3781 /* Handle the first parameter of a valued procedure specially. */
3784 /* Otherwise, see if a Mechanism was supplied that forced this
3785 parameter to be passed one way or another. */
3788 ;
3792 {
3796 mech))
3798 else
3800 }
3801 else
3802 {
3805 }
3807 gnu_param
3812 /* We are returned either a PARM_DECL or a type if no parameter
3813 needs to be passed; in either case, adjust the type. */
3816 else
3817 {
3820 }
3823 {
3824 /* If it's an exported subprogram, we build a parameter list
3825 in parallel, in case we need to emit a stub for it. */
3827 {
3828 gnu_stub_param_list
3830 /* Change By_Descriptor parameter to By_Reference for
3831 the internal version of an exported subprogram. */
3833 {
3834 gnu_param
3839 }
3840 else
3842 }
3849 /* If a parameter is a pointer, this function may modify
3850 memory through it and thus shouldn't be considered
3851 a pure function. Also, the memory may be modified
3852 between two calls, so they can't be CSE'ed. The latter
3853 case also handles by-ref parameters. */
3857 }
3860 {
3862 {
3867 }
3876 gnu_return_list);
3877 }
3878 }
3880 /* Do not compute record for out parameters if subprogram is
3881 stubbed since structures are incomplete for the back-end. */
3886 /* If we have a CICO list but it has only one entry, we convert
3887 this function into a function that simply returns that one
3888 object. */
3893 prepend_one_attribute_to
3896 gnat_entity);
3898 /* The lists have been built in reverse. */
3908 gnu_type
3914 gnu_stub_type
3919 /* A subprogram (something that doesn't return anything) shouldn't
3920 be considered Pure since there would be no reason for such a
3921 subprogram. Note that procedures with Out (or In Out) parameters
3922 have already been converted into a function with a return type. */
3926 /* The semantics of "pure" in Ada essentially matches that of "const"
3927 in the back-end. In particular, both properties are orthogonal to
3928 the "nothrow" property. But this is true only if the EH circuitry
3929 is explicit in the internal representation of the back-end. If we
3930 are to completely hide the EH circuitry from it, we need to declare
3931 that calls to pure Ada subprograms that can throw have side effects
3932 since they can trigger an "abnormal" transfer of control flow; thus
3933 they can be neither "const" nor "pure" in the back-end sense. */
3934 gnu_type
3944 gnu_stub_type
3951 /* If we have a builtin decl for that function, check the signatures
3952 compatibilities. If the signatures are compatible, use the builtin
3953 decl. If they are not, we expect the checker predicate to have
3954 posted the appropriate errors, and just continue with what we have
3955 so far. */
3957 {
3961 {
3965 }
3966 }
3968 /* If there was no specified Interface_Name and the external and
3969 internal names of the subprogram are the same, only use the
3970 internal name to allow disambiguation of nested subprograms. */
3974 /* If we are defining the subprogram and it has an Address clause
3975 we must get the address expression from the saved GCC tree for the
3976 subprogram if it has a Freeze_Node. Otherwise, we elaborate
3977 the address expression here since the front-end has guaranteed
3978 in that case that the elaboration has no effects. If there is
3979 an Address clause and we are not defining the object, just
3980 make it a constant. */
3982 {
3986 gnu_address
3993 /* Convert the type of the object to a reference type that can
3994 alias everything as per 13.3(19). */
3995 gnu_type
4000 gnu_decl
4005 }
4011 else
4012 {
4014 {
4018 }
4024 gnat_entity);
4026 {
4027 tree gnu_stub_decl
4032 gnat_entity);
4034 }
4036 /* This is unrelated to the stub built right above. */
4039 }
4040 }
4051 {
4052 /* Get the "full view" of this entity. If this is an incomplete
4053 entity from a limited with, treat its non-limited view as the
4054 full view. Otherwise, use either the full view or the underlying
4055 full view, whichever is present. This is used in all the tests
4056 below. */
4057 Entity_Id full_view
4065 /* If this is an incomplete type with no full view, it must be a Taft
4066 Amendment type, in which case we return a dummy type. Otherwise,
4067 just get the type from its Etype. */
4069 {
4072 else
4073 {
4077 }
4079 }
4081 /* If we already made a type for the full view, reuse it. */
4083 {
4086 }
4088 /* Otherwise, if we are not defining the type now, get the type
4089 from the full view. But always get the type from the full view
4090 for define on use types, since otherwise we won't see them! */
4096 {
4100 }
4102 /* For incomplete types, make a dummy type entry which will be
4103 replaced later. */
4106 /* Save this type as the full declaration's type so we can do any
4107 needed updates when we see it. */
4113 }
4115 /* Simple class_wide types are always viewed as their root_type
4116 by Gigi unless an Equivalent_Type is specified. */
4128 else
4140 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4141 we've already saved it, so we don't try to. */
4148 }
4150 /* If we had a case where we evaluated another type and it might have
4151 defined this one, handle it here. */
4153 {
4156 }
4158 /* If we are processing a type and there is either no decl for it or
4159 we just made one, do some common processing for the type, such as
4160 handling alignment and possible padding. */
4163 {
4171 /* ??? Don't set the size for a String_Literal since it is either
4172 confirming or we don't handle it properly (if the low bound is
4173 non-constant). */
4179 /* If a size was specified, see if we can make a new type of that size
4180 by rearranging the type, for example from a fat to a thin pointer. */
4182 {
4183 gnu_type
4190 }
4192 /* If the alignment hasn't already been processed and this is
4193 not an unconstrained array, see if an alignment is specified.
4194 If not, we pick a default alignment for atomic objects. */
4196 ;
4198 {
4202 /* Warn on suspiciously large alignments. This should catch
4203 errors about the (alignment,byte)/(size,bit) discrepancy. */
4205 {
4206 tree size;
4208 /* If a size was specified, take it into account. Otherwise
4209 use the RM size for records as the type size has already
4210 been adjusted to the alignment. */
4218 else
4221 /* Consider an alignment as suspicious if the alignment/size
4222 ratio is greater or equal to the byte/bit ratio. */
4227 gnat_entity);
4228 }
4229 }
4240 /* See if we need to pad the type. If we did, and made a record,
4241 the name of the new type may be changed. So get it back for
4242 us when we make the new TYPE_DECL below. */
4249 {
4253 }
4257 /* If we are at global level, GCC will have applied variable_size to
4258 the type, but that won't have done anything. So, if it's not
4259 a constant or self-referential, call elaborate_expression_1 to
4260 make a variable for the size rather than calculating it each time.
4261 Handle both the RM size and the actual size. */
4266 {
4270 {
4277 }
4278 else
4279 {
4286 /* ??? For now, store the size as a multiple of the alignment
4287 in bytes so that we can see the alignment from the tree. */
4289 = build_binary_op
4291 elaborate_expression_1
4302 SET_TYPE_ADA_SIZE
4305 gnat_entity,
4309 }
4310 }
4312 /* If this is a record type or subtype, call elaborate_expression_1 on
4313 any field position. Do this for both global and local types.
4314 Skip any fields that we haven't made trees for to avoid problems with
4315 class wide types. */
4320 {
4323 /* ??? Unfortunately, GCC needs to be able to prove the
4324 alignment of this offset and if it's a variable, it can't.
4325 In GCC 3.4, we'll use DECL_OFFSET_ALIGN in some way, but
4326 right now, we have to put in an explicit multiply and
4327 divide by that value. */
4329 {
4331 = build_binary_op
4333 elaborate_expression_1
4343 /* ??? The context of gnu_field is not necessarily gnu_type so
4344 the MULT_EXPR node built above may not be marked by the call
4345 to create_type_decl below. Mark it manually for now. */
4348 }
4349 }
4353 | (TYPE_QUAL_VOLATILE
4369 else
4371 }
4374 {
4377 /* Back-annotate the Alignment of the type if not already in the
4378 tree. Likewise for sizes. */
4384 {
4385 /* If the size is self-referential, we annotate the maximum
4386 value of that size. */
4395 {
4396 /* In this mode the tag and the parent components are not
4397 generated by the front-end, so the sizes must be adjusted
4398 explicitly now. */
4402 {
4403 size_offset
4407 }
4408 else
4416 }
4417 }
4421 }
4431 /* If we haven't already, associate the ..._DECL node that we just made with
4432 the input GNAT entity node. */
4436 /* If this is an enumeral or floating-point type, we were not able to set
4437 the bounds since they refer to the type. These bounds are always static.
4439 For enumeration types, also write debugging information and declare the
4440 enumeration literal table, if needed. */
4444 {
4447 /* If this is a padded type, we need to use the underlying type. */
4452 /* If this is a floating point type and we haven't set a floating
4453 point type yet, use this in the evaluation of the bounds. */
4463 {
4464 /* Since this has both a typedef and a tag, avoid outputting
4465 the name twice. */
4468 }
4469 }
4471 /* If we deferred processing of incomplete types, re-enable it. If there
4472 were no other disables and we have some to process, do so. */
4474 {
4476 {
4479 /* We are back to level 0 for the deferring of incomplete types.
4480 But processing these incomplete types below may itself require
4481 deferring, so preserve what we have and restart from scratch. */
4485 /* For finalization, however, all types must be complete so we
4486 cannot do the same because deferred incomplete types may end up
4487 referencing each other. Process them all recursively first. */
4488 defer_finalize_level++;
4491 {
4498 }
4500 defer_finalize_level--;
4501 }
4503 /* All the deferred incomplete types have been processed so we can
4504 now proceed with the finalization of the deferred types. */
4506 {
4508 tree t;
4514 }
4515 }
4517 /* If we are not defining this type, see if it's in the incomplete list.
4518 If so, handle that list entry now. */
4520 {
4525 {
4529 }
4530 }
4533 force_global--;
4542 }
4544 /* Similar, but if the returned value is a COMPONENT_REF, return the
4545 FIELD_DECL. */
4547 tree
4549 {
4556 }
4558 /* Wrap up compilation of DECL, a TYPE_DECL, possibly deferring it.
4559 Every TYPE_DECL generated for a type definition must be passed
4560 to this function once everything else has been done for it. */
4562 void
4564 {
4565 /* We need to defer finalizing the type if incomplete types
4566 are being deferred or if they are being processed. */
4569 else
4571 }
4573 /* Same as above but without deferring the compilation. This
4574 function should not be invoked directly on a TYPE_DECL. */
4576 static void
4578 {
4584 /* Now process all the variants. This is needed for STABS. */
4586 {
4591 {
4594 }
4597 }
4598 }
4600 /* Finalize any From_With_Type incomplete types. We do this after processing
4601 our compilation unit and after processing its spec, if this is a body. */
4603 void
4605 {
4611 {
4618 }
4619 }
4621 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
4622 kind of type (such E_Task_Type) that has a different type which Gigi
4623 uses for its representation. If the type does not have a special type
4624 for its representation, return GNAT_ENTITY. If a type is supposed to
4625 exist, but does not, abort unless annotating types, in which case
4626 return Empty. If GNAT_ENTITY is Empty, return Empty. */
4628 Entity_Id
4630 {
4637 {
4663 }
4667 }
4669 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
4670 using MECH as its passing mechanism, to be placed in the parameter
4671 list built for GNAT_SUBPROG. Assume a foreign convention for the
4672 latter if FOREIGN is true. Also set CICO to true if the parameter
4673 must use the copy-in copy-out implementation mechanism.
4675 The returned tree is a PARM_DECL, except for those cases where no
4676 parameter needs to be actually passed to the subprogram; the type
4677 of this "shadow" parameter is then returned instead. */
4679 static tree
4682 {
4686 /* The parameter can be indirectly modified if its address is taken. */
4689 tree gnu_param;
4691 /* Copy-return is used only for the first parameter of a valued procedure.
4692 It's a copy mechanism for which a parameter is never allocated. */
4694 {
4698 }
4700 /* If this is either a foreign function or if the underlying type won't
4701 be passed by reference, strip off possible padding type. */
4704 {
4708 || foreign
4712 }
4714 /* If this is a read-only parameter, make a variant of the type that is
4715 read-only. ??? However, if this is an unconstrained array, that type
4716 can be very complex, so skip it for now. Likewise for any other
4717 self-referential type. */
4725 /* For foreign conventions, pass arrays as pointers to the element type.
4726 First check for unconstrained array and get the underlying array. */
4728 gnu_param_type
4731 /* VMS descriptors are themselves passed by reference. */
4733 gnu_param_type
4736 gnat_subprog));
4738 /* Arrays are passed as pointers to element type for foreign conventions. */
4742 {
4743 /* Strip off any multi-dimensional entries, then strip
4744 off the last array to get the component type. */
4758 }
4760 /* Fat pointers are passed as thin pointers for foreign conventions. */
4762 gnu_param_type
4765 /* If we must pass or were requested to pass by reference, do so.
4766 If we were requested to pass by copy, do so.
4767 Otherwise, for foreign conventions, pass In Out or Out parameters
4768 or aggregates by reference. For COBOL and Fortran, pass all
4769 integer and FP types that way too. For Convention Ada, use
4770 the standard Ada default. */
4774 && ((foreign
4776 || (foreign
4781 || (!foreign
4783 {
4786 }
4788 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
4795 /* If this is an Out parameter that isn't passed by reference and isn't
4796 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
4797 it will be a VAR_DECL created when we process the procedure, so just
4798 return its type. For the special parameter of a valued procedure,
4799 never pass it in.
4801 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
4802 Out parameters with discriminants or implicit initial values to be
4803 handled like In Out parameters. These type are normally built as
4804 aggregates, hence passed by reference, except for some packed arrays
4805 which end up encoded in special integer types.
4807 The exception we need to make is then for packed arrays of records
4808 with discriminants or implicit initial values. We have no light/easy
4809 way to check for the latter case, so we merely check for packed arrays
4810 of records. This may lead to useless copy-in operations, but in very
4811 rare cases only, as these would be exceptions in a set of already
4812 exceptional situations. */
4814 && !by_ref
4815 && (by_return
4832 /* If no Mechanism was specified, indicate what we're using, then
4833 back-annotate it. */
4839 }
4841 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
4843 static bool
4845 {
4852 return
4854 }
4856 /* Return true if the array type specified by GNAT_TYPE and GNU_TYPE has
4857 a non-aliased component in the back-end sense. */
4859 static bool
4861 {
4862 /* If the type below this is a multi-array type, then
4863 this does not have aliased components. */
4872 }
4873 \f
4874 /* Given GNAT_ENTITY, elaborate all expressions that are required to
4875 be elaborated at the point of its definition, but do nothing else. */
4877 void
4879 {
4881 {
4888 {
4892 /* ??? Tests for avoiding static constraint error expression
4893 is needed until the front stops generating bogus conversions
4894 on bounds of real types. */
4903 }
4906 {
4910 /* If this is a record extension, go a level further to find the
4911 record definition. */
4914 }
4924 {
4925 Node_Id gnat_discriminant_expr;
4926 Entity_Id gnat_field;
4929 gnat_discriminant_expr
4934 /* ??? For now, ignore access discriminants. */
4937 gnat_entity,
4939 }
4942 }
4943 }
4944 \f
4945 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
4946 any entities on its entity chain similarly. */
4948 void
4950 {
4951 Entity_Id gnat_sub_entity;
4954 /* If this has an entity list, process all in the list. */
4971 /* Now clear this if it has been defined, but only do so if it isn't
4972 a subprogram or parameter. We could refine this, but it isn't
4973 worth it. If this is statically allocated, it is supposed to
4974 hang around out of cope. */
4977 {
4980 }
4981 }
4982 \f
4983 /* Set the alias set of GNU_NEW_TYPE to be that of GNU_OLD_TYPE. If this
4984 is a multi-dimensional array type, do this recursively. */
4986 static void
4988 {
4989 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
4990 of a one-dimensional array, since the padding has the same alias set
4991 as the field type, but if it's a multi-dimensional array, we need to
4992 see the inner types. */
4998 /* We need to be careful here in case GNU_OLD_TYPE is an unconstrained
4999 array. In that case, it doesn't have the same shape as GNU_NEW_TYPE,
5000 so we need to go down to what does. */
5002 gnu_old_type
5012 }
5013 \f
5014 /* Return a TREE_LIST describing the substitutions needed to reflect
5015 discriminant substitutions from GNAT_SUBTYPE to GNAT_TYPE and add
5016 them to GNU_LIST. If GNAT_TYPE is not specified, use the base type
5017 of GNAT_SUBTYPE. The substitutions can be in any order. TREE_PURPOSE
5018 gives the tree for the discriminant and TREE_VALUES is the replacement
5019 value. They are in the form of operands to substitute_in_expr.
5020 DEFINITION is as in gnat_to_gnu_entity. */
5022 static tree
5025 {
5026 Entity_Id gnat_discrim;
5027 Node_Id gnat_value;
5038 /* Ignore access discriminants. */
5041 elaborate_expression
5045 gnu_list);
5048 }
5049 \f
5050 /* Return true if the size represented by GNU_SIZE can be handled by an
5051 allocation. If STATIC_P is true, consider only what can be done with a
5052 static allocation. */
5054 static bool
5056 {
5057 HOST_WIDE_INT our_size;
5059 /* If this is not a static allocation, the only case we want to forbid
5060 is an overflowing size. That will be converted into a raise a
5061 Storage_Error. */
5066 /* Otherwise, we need to deal with both variable sizes and constant
5067 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
5068 since assemblers may not like very large sizes. */
5074 }
5075 \f
5076 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
5077 NAME, ARGS and ERROR_POINT. */
5079 static void
5082 tree attr_name,
5083 tree attr_args,
5084 Node_Id attr_error_point)
5085 {
5095 }
5097 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
5099 static void
5101 {
5102 Node_Id gnat_temp;
5107 {
5116 {
5118 (gnat_to_gnu
5125 (gnat_to_gnu
5126 (Expression
5129 }
5132 {
5159 }
5162 /* Prepend to the list now. Make a list of the argument we might
5163 have, as GCC expects it. */
5164 prepend_one_attribute_to
5171 }
5172 }
5173 \f
5174 /* Get the unpadded version of a GNAT type. */
5176 tree
5178 {
5185 }
5186 \f
5187 /* Called when we need to protect a variable object using a save_expr. */
5189 tree
5191 {
5198 {
5206 }
5207 else
5209 }
5210 \f
5211 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
5212 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
5213 return the GCC tree to use for that expression. GNU_NAME is the
5214 qualification to use if an external name is appropriate and DEFINITION is
5215 nonzero if this is a definition of GNAT_ENTITY. If NEED_VALUE is nonzero,
5216 we need a result. Otherwise, we are just elaborating this for
5217 side-effects. If NEED_DEBUG is nonzero we need the symbol for debugging
5218 purposes even if it isn't needed for code generation. */
5220 static tree
5224 {
5225 tree gnu_expr;
5227 /* If we already elaborated this expression (e.g., it was involved
5228 in the definition of a private type), use the old value. */
5232 /* If we don't need a value and this is static or a discriminant, we
5233 don't need to do anything. */
5240 /* Otherwise, convert this tree to its GCC equivalent. */
5241 gnu_expr
5245 /* Save the expression in case we try to elaborate this entity again. Since
5246 this is not a DECL, don't check it. Don't save if it's a discriminant. */
5251 }
5253 /* Similar, but take a GNU expression. */
5255 static tree
5259 {
5261 /* Strip any conversions to see if the expression is a readonly variable.
5262 ??? This really should remain readonly, but we have to think about
5263 the typing of the tree here. */
5268 /* In most cases, we won't see a naked FIELD_DECL here because a
5269 discriminant reference will have been replaced with a COMPONENT_REF
5270 when the type is being elaborated. However, there are some cases
5271 involving child types where we will. So convert it to a COMPONENT_REF
5272 here. We have to hope it will be at the highest level of the
5273 expression in these cases. */
5279 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
5280 that is a constant, make a variable that is initialized to contain the
5281 bound when the package containing the definition is elaborated. If
5282 this entity is defined at top level and a bound or discriminant value
5283 isn't a constant or a reference to a discriminant, replace the bound
5284 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
5285 rely here on the fact that an expression cannot contain both the
5286 discriminant and some other variable. */
5294 /* If this is a static expression or contains a discriminant, we don't
5295 need the variable for debugging (and can't elaborate anyway if a
5296 discriminant). */
5302 /* Now create the variable if we need it. */
5304 gnu_decl
5311 /* We only need to use this variable if we are in global context since GCC
5312 can do the right thing in the local case. */
5317 else
5319 }
5320 \f
5321 /* Create a record type that contains a SIZE bytes long field of TYPE with a
5322 starting bit position so that it is aligned to ALIGN bits, and leaving at
5323 least ROOM bytes free before the field. BASE_ALIGN is the alignment the
5324 record is guaranteed to get. */
5326 tree
5329 {
5330 /* We will be crafting a record type with one field at a position set to be
5331 the next multiple of ALIGN past record'address + room bytes. We use a
5332 record placeholder to express record'address. */
5337 tree record_addr_st
5340 /* The diagram below summarizes the shape of what we manipulate:
5342 <--------- pos ---------->
5343 { +------------+-------------+-----------------+
5344 record =>{ |############| ... | field (type) |
5345 { +------------+-------------+-----------------+
5346 |<-- room -->|<- voffset ->|<---- size ----->|
5347 o o
5348 | |
5349 record_addr vblock_addr
5351 Every length is in sizetype bytes there, except "pos" which has to be
5352 set as a bit position in the GCC tree for the record. */
5365 /* Compute VOFFSET and then POS. The next byte position multiple of some
5366 alignment after some address is obtained by "and"ing the alignment minus
5367 1 with the two's complement of the address. */
5373 /* POS = (ROOM + VOFFSET) * BIT_PER_UNIT, in bitsizetype. */
5378 bitsize_unit_node);
5380 /* Craft the GCC record representation. We exceptionally do everything
5381 manually here because 1) our generic circuitry is not quite ready to
5382 handle the complex position/size expressions we are setting up, 2) we
5383 have a strong simplifying factor at hand: we know the maximum possible
5384 value of voffset, and 3) we have to set/reset at least the sizes in
5385 accordance with this maximum value anyway, as we need them to convey
5386 what should be "alloc"ated for this type.
5388 Use -1 as the 'addressable' indication for the field to prevent the
5389 creation of a bitfield. We don't need one, it would have damaging
5390 consequences on the alignment computation, and create_field_decl would
5391 make one without this special argument, for instance because of the
5392 complex position expression. */
5404 bitsize_unit_node),
5414 }
5415 \f
5416 /* Return the result of rounding T up to ALIGN. */
5420 {
5425 }
5427 /* TYPE is a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE that is being used
5428 as the field type of a packed record if IN_RECORD is true, or as the
5429 component type of a packed array if IN_RECORD is false. See if we can
5430 rewrite it either as a type that has a non-BLKmode, which we can pack
5431 tighter in the packed record case, or as a smaller type with BLKmode.
5432 If so, return the new type. If not, return the original type. */
5434 static tree
5436 {
5441 /* No point in doing anything if the size is zero. */
5447 /* Copy the name and flags from the old type to that of the new. Note
5448 that we rely on the pointer equality created here for TYPE_NAME at
5449 the end of gnat_to_gnu. */
5456 /* If we are in a record and have a small size, set the alignment to
5457 try for an integral mode. Otherwise set it to try for a smaller
5458 type with BLKmode. */
5460 {
5463 }
5464 else
5465 {
5468 /* Do not try to shrink the size if the RM size is not constant. */
5473 /* Round the RM size up to a unit boundary to get the minimal size
5474 for a BLKmode record. Give up if it's already the size. */
5482 }
5486 /* Now copy the fields, keeping the position and size as we don't
5487 want to propagate packedness downward. But make an exception
5488 for the last field in order to ditch the padding bits. */
5491 {
5504 else
5513 SET_DECL_ORIGINAL_FIELD
5522 }
5527 /* If this is a padding record, we never want to make the size smaller
5528 than what was specified. For QUAL_UNION_TYPE, also copy the size. */
5531 {
5534 }
5535 else
5536 {
5540 }
5547 /* Try harder to get a packable type if necessary, for example
5548 in case the record itself contains a BLKmode field. */
5553 /* If neither the mode nor the size has shrunk, return the old type. */
5558 }
5559 \f
5560 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
5561 if needed. We have already verified that SIZE and TYPE are large enough.
5563 GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
5564 to issue a warning.
5566 IS_USER_TYPE is true if we must be sure we complete the original type.
5568 DEFINITION is true if this type is being defined.
5570 SAME_RM_SIZE is true if the RM_Size of the resulting type is to be set
5571 to SIZE too; otherwise, it's set to the RM_Size of the original type. */
5573 tree
5577 {
5583 /* If TYPE is a padded type, see if it agrees with any size and alignment
5584 we were given. If so, return the original type. Otherwise, strip
5585 off the padding, since we will either be returning the inner type
5586 or repadding it. If no size or alignment is specified, use that of
5587 the original padded type. */
5589 {
5606 }
5608 /* If the size is either not being changed or is being made smaller (which
5609 is not done here (and is only valid for bitfields anyway), show the size
5610 isn't changing. Likewise, clear the alignment if it isn't being
5611 changed. Then return if we aren't doing anything. */
5624 /* We used to modify the record in place in some cases, but that could
5625 generate incorrect debugging information. So make a new record
5626 type and name. */
5632 /* If we were making a type, complete the original type and give it a
5633 name. */
5640 gnat_entity);
5642 /* If we are changing the alignment and the input type is a record with
5643 BLKmode and a small constant size, try to make a form that has an
5644 integral mode. That might allow this record to have an integral mode,
5645 which will be much more efficient. There is no point in doing this if a
5646 size is specified unless it is also smaller than the maximum mode size
5647 and it is incorrect to do this if the size of the original type is not a
5648 multiple of the alignment. */
5654 && (!size
5677 /* Do not finalize it until after the auxiliary record is built. */
5680 /* Set the same size for its RM_size if requested; otherwise reuse
5681 the RM_size of the original type. */
5684 /* Unless debugging information isn't being written for the input type,
5685 write a record that shows what we are a subtype of and also make a
5686 variable that indicates our size, if still variable. */
5692 {
5714 }
5718 /* If the size was widened explicitly, maybe give a warning. Take the
5719 original size as the maximum size of the input if there was an
5720 unconstrained record involved and round it up to the specified alignment,
5721 if one was specified. */
5733 {
5746 /* Generate message only for entities that come from source, since
5747 if we have an entity created by expansion, the message will be
5748 generated for some other corresponding source entity. */
5751 gnat_entity,
5758 }
5761 }
5762 \f
5763 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
5764 the value passed against the list of choices. */
5766 tree
5768 {
5769 Node_Id choice;
5770 Node_Id gnat_temp;
5775 {
5777 {
5782 /* There's no good type to use here, so we might as well use
5783 integer_type_node. */
5784 this_test
5798 this_test
5808 /* This represents either a subtype range, an enumeration
5809 literal, or a constant Ekind says which. If an enumeration
5810 literal or constant, fall through to the next case. */
5813 {
5819 this_test
5826 }
5827 /* ... fall through ... */
5832 single);
5841 }
5845 }
5848 }
5849 \f
5850 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
5851 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
5853 static int
5855 {
5856 /* If the field contains an item of variable size, we cannot pack it
5857 because we cannot create temporaries of non-fixed size in case
5858 we need to take the address of the field. See addressable_p and
5859 the notes on the addressability issues for further details. */
5863 /* If the alignment of the record is specified and the field type
5864 is over-aligned, request Storage_Unit alignment for the field. */
5866 {
5869 else
5871 }
5874 }
5876 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
5877 placed in GNU_RECORD_TYPE.
5879 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
5880 record has Component_Alignment of Storage_Unit, -2 if the enclosing
5881 record has a specified alignment.
5883 DEFINITION is true if this field is for a record being defined. */
5885 static tree
5888 {
5892 bool needs_strict_alignment
5896 /* If this field requires strict alignment, we cannot pack it because
5897 it would very likely be under-aligned in the record. */
5900 else
5903 /* If a size is specified, use it. Otherwise, if the record type is packed,
5904 use the official RM size. See "Handling of Type'Size Values" in Einfo
5905 for further details. */
5912 else
5915 /* If we have a specified size that's smaller than that of the field type,
5916 or a position is specified, and the field type is also a record that's
5917 BLKmode, see if we can get either an integral mode form of the type or
5918 a smaller BLKmode form. If we can, show a size was specified for the
5919 field if there wasn't one already, so we know to make this a bitfield
5920 and avoid making things wider.
5922 Doing this is first useful if the record is packed because we may then
5923 place the field at a non-byte-aligned position and so achieve tighter
5924 packing.
5926 This is in addition *required* if the field shares a byte with another
5927 field and the front-end lets the back-end handle the references, because
5928 GCC does not handle BLKmode bitfields properly.
5930 We avoid the transformation if it is not required or potentially useful,
5931 as it might entail an increase of the field's alignment and have ripple
5932 effects on the outer record type. A typical case is a field known to be
5933 byte aligned and not to share a byte with another field.
5935 Besides, we don't even look the possibility of a transformation in cases
5936 known to be in error already, for instance when an invalid size results
5937 from a component clause. */
5943 || (gnu_size
5946 {
5947 /* See what the alternate type and size would be. */
5950 bool has_byte_aligned_clause
5955 /* Compute whether we should avoid the substitution. */
5956 bool reject
5957 /* There is no point substituting if there is no change... */
5959 /* ... nor when the field is known to be byte aligned and not to
5960 share a byte with another field. */
5961 || (has_byte_aligned_clause
5963 /* The size of an aliased field must be an exact multiple of the
5964 type's alignment, which the substitution might increase. Reject
5965 substitutions that would so invalidate a component clause when the
5966 specified position is byte aligned, as the change would have no
5967 real benefit from the packing standpoint anyway. */
5969 && has_byte_aligned_clause
5972 /* Substitute unless told otherwise. */
5974 {
5979 }
5980 }
5982 /* If we are packing the record and the field is BLKmode, round the
5983 size up to a byte boundary. */
5988 {
5993 /* Ensure the position does not overlap with the parent subtype,
5994 if there is one. */
5996 {
5997 tree gnu_parent
6003 {
6004 post_error_ne_tree
6008 }
6009 }
6011 /* If this field needs strict alignment, ensure the record is
6012 sufficiently aligned and that that position and size are
6013 consistent with the alignment. */
6015 {
6021 {
6023 post_error_ne_tree
6029 post_error_ne_tree
6035 post_error_ne_tree
6041 }
6046 {
6048 post_error_ne_num
6054 post_error_ne_num
6060 post_error_ne_num
6065 else
6069 }
6070 }
6074 }
6076 /* If the record has rep clauses and this is the tag field, make a rep
6077 clause for it as well. */
6080 {
6083 }
6085 else
6088 /* We need to make the size the maximum for the type if it is
6089 self-referential and an unconstrained type. In that case, we can't
6090 pack the field since we can't make a copy to align it. */
6092 && !gnu_size
6095 {
6098 }
6100 /* If a size is specified, adjust the field's type to it. */
6102 {
6103 /* If the field's type is justified modular, we would need to remove
6104 the wrapper to (better) meet the layout requirements. However we
6105 can do so only if the field is not aliased to preserve the unique
6106 layout and if the prescribed size is not greater than that of the
6107 packed array to preserve the justification. */
6115 gnu_field_type
6120 }
6122 /* Otherwise (or if there was an error), don't specify a position. */
6123 else
6129 /* Now create the decl for the field. */
6141 }
6142 \f
6143 /* Return true if TYPE is a type with variable size, a padding type with a
6144 field of variable size or is a record that has a field such a field. */
6146 static bool
6148 {
6149 tree field;
6169 }
6170 \f
6171 /* qsort comparer for the bit positions of two record components. */
6173 static int
6175 {
6178 const int ret
6182 }
6184 /* Return a GCC tree for a record type given a GNAT Component_List and a chain
6185 of GCC trees for fields that are in the record and have already been
6186 processed. When called from gnat_to_gnu_entity during the processing of a
6187 record type definition, the GCC nodes for the discriminants will be on
6188 the chain. The other calls to this function are recursive calls from
6189 itself for the Component_List of a variant and the chain is empty.
6191 PACKED is 1 if this is for a packed record, -1 if this is for a record
6192 with Component_Alignment of Storage_Unit, -2 if this is for a record
6193 with a specified alignment.
6195 DEFINITION is true if we are defining this record.
6197 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
6198 with a rep clause is to be added. If it is nonzero, that is all that
6199 should be done with such fields.
6201 CANCEL_ALIGNMENT, if true, means the alignment should be zeroed before
6202 laying out the record. This means the alignment only serves to force fields
6203 to be bitfields, but not require the record to be that aligned. This is
6204 used for variants.
6206 ALL_REP, if true, means a rep clause was found for all the fields. This
6207 simplifies the logic since we know we're not in the mixed case.
6209 DO_NOT_FINALIZE, if true, means that the record type is expected to be
6210 modified afterwards so it will not be sent to the back-end for finalization.
6212 UNCHECKED_UNION, if true, means that we are building a type for a record
6213 with a Pragma Unchecked_Union.
6215 The processing of the component list fills in the chain with all of the
6216 fields of the record and then the record type is finished. */
6218 static void
6223 {
6224 Node_Id component_decl;
6225 Entity_Id gnat_field;
6226 Node_Id variant_part;
6232 /* For each variable within each component declaration create a GCC field
6233 and add it to the list, skipping any pragmas in the list. */
6238 {
6243 else
6244 {
6248 /* If this is the _Tag field, put it before any discriminants,
6249 instead of after them as is the case for all other fields.
6250 Ignore field of void type if only annotating. */
6253 else
6254 {
6257 }
6258 }
6261 }
6263 /* At the end of the component list there may be a variant part. */
6266 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
6267 mutually exclusive and should go in the same memory. To do this we need
6268 to treat each variant as a record whose elements are created from the
6269 component list for the variant. So here we create the records from the
6270 lists for the variants and put them all into the QUAL_UNION_TYPE.
6271 If this is an Unchecked_Union, we make a UNION_TYPE instead or
6272 use GNU_RECORD_TYPE if there are no fields so far. */
6274 {
6276 Node_Id variant;
6278 tree gnu_var_name
6282 tree gnu_union_type;
6283 tree gnu_union_name;
6284 tree gnu_union_field;
6293 /* Reuse an enclosing union if all fields are in the variant part
6294 and there is no representation clause on the record, to match
6295 the layout of C unions. There is an associated check below. */
6300 else
6301 {
6302 gnu_union_type
6307 }
6312 {
6314 tree gnu_inner_name;
6315 tree gnu_qual;
6323 /* Set the alignment of the inner type in case we need to make
6324 inner objects into bitfields, but then clear it out
6325 so the record actually gets only the alignment required. */
6329 /* Similarly, if the outer record has a size specified and all fields
6330 have record rep clauses, we can propagate the size into the
6331 variant part. */
6333 {
6337 }
6339 /* Create the record type for the variant. Note that we defer
6340 finalizing it until after we are sure to actually use it. */
6351 /* If this is an Unchecked_Union and we have exactly one field,
6352 use this field directly to match the layout of C unions. */
6357 else
6358 {
6359 /* Deal with packedness like in gnat_to_gnu_field. */
6360 int field_packed
6363 /* Finalize the record type now. We used to throw away
6364 empty records but we no longer do that because we need
6365 them to generate complete debug info for the variant;
6366 otherwise, the union type definition will be lacking
6367 the fields associated with these empty variants. */
6372 (all_rep_and_size
6375 (all_rep_and_size
6383 }
6387 }
6389 /* Only make the QUAL_UNION_TYPE if there are any non-empty variants. */
6391 {
6393 {
6397 }
6402 /* If GNU_UNION_TYPE is our record type, it means we must have an
6403 Unchecked_Union with no fields. Verify that and, if so, just
6404 return. */
6406 {
6408 && !gnu_field_list
6411 }
6413 gnu_union_field
6415 packed,
6422 }
6423 }
6425 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
6426 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do this
6427 in a separate pass since we want to handle the discriminants but can't
6428 play with them until we've used them in debugging data above.
6430 ??? Note: if we then reorder them, debugging information will be wrong,
6431 but there's nothing that can be done about this at the moment. */
6433 {
6435 {
6440 else
6446 }
6447 else
6448 {
6451 }
6452 }
6454 /* If we have any items in our rep'ed field list, it is not the case that all
6455 the fields in the record have rep clauses, and P_REP_LIST is nonzero,
6456 set it and ignore the items. */
6460 {
6461 /* Otherwise, sort the fields by bit position and put them into their
6462 own record if we have any fields without rep clauses. */
6463 tree gnu_rep_type
6475 /* Put the fields in the list in order of increasing position, which
6476 means we start from the end. */
6479 {
6483 }
6486 {
6492 }
6493 else
6494 {
6497 }
6498 }
6505 }
6506 \f
6507 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
6508 placed into an Esize, Component_Bit_Offset, or Component_Size value
6509 in the GNAT tree. */
6511 static Uint
6513 {
6515 TCode tcode;
6521 /* See if we've already saved the value for this node. */
6523 {
6534 }
6536 /* If we do not return inside this switch, TCODE will be set to the
6537 code to use for a Create_Node operand and LEN (set above) will be
6538 the number of recursive calls for us to make. */
6541 {
6546 /* This may have come from a conversion from some smaller type,
6547 so ensure this is in bitsizetype. */
6550 /* For negative values, use NEGATE_EXPR of the supplied value. */
6552 {
6553 /* The ridiculous code below is to handle the case of the largest
6554 negative integer. */
6557 tree temp;
6560 {
6561 negative_size
6564 bitsize_one_node));
6566 }
6573 }
6580 /* This peculiar test is to make sure that the size fits in an int
6581 on machines where HOST_WIDE_INT is not "int". */
6584 else
6588 /* The only case we handle here is a simple discriminant reference. */
6596 else
6602 /* Now just list the operations we handle. */
6634 }
6636 /* Now get each of the operands that's relevant for this code. If any
6637 cannot be expressed as a repinfo node, say we can't. */
6642 {
6646 }
6650 /* Save the result in the cache. */
6652 {
6656 }
6659 }
6661 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding
6662 GCC type, set Component_Bit_Offset and Esize to the position and size
6663 used by Gigi. */
6665 static void
6667 {
6668 tree gnu_list;
6669 tree gnu_entry;
6670 Entity_Id gnat_field;
6672 /* We operate by first making a list of all fields and their positions
6673 (we can get the sizes easily at any time) by a recursive call
6674 and then update all the sizes into the tree. */
6677 BIGGEST_ALIGNMENT);
6684 {
6688 gnu_list);
6691 {
6693 {
6694 /* In this mode the tag and parent components have not been
6695 generated, so we add the appropriate offset to each
6696 component. For a component appearing in the current
6697 extension, the offset is the size of the parent. */
6700 parent_offset
6702 bitsizetype);
6703 else
6705 }
6707 Set_Component_Bit_Offset
6709 annotate_value
6714 parent_offset)));
6718 }
6721 {
6722 /* If there is no gnu_entry, this is an inherited component whose
6723 position is the same as in the parent type. */
6724 Set_Component_Bit_Offset
6729 }
6730 }
6731 }
6733 /* Scan all fields in GNU_TYPE and build entries where TREE_PURPOSE is the
6734 FIELD_DECL and TREE_VALUE a TREE_LIST with TREE_PURPOSE being the byte
6735 position and TREE_VALUE being a TREE_LIST with TREE_PURPOSE the value to be
6736 placed into DECL_OFFSET_ALIGN and TREE_VALUE the bit position. GNU_POS is
6737 to be added to the position, GNU_BITPOS to the bit position, OFFSET_ALIGN is
6738 the present value of DECL_OFFSET_ALIGN and GNU_LIST is a list of the entries
6739 so far. */
6741 static tree
6744 {
6745 tree gnu_field;
6750 {
6755 unsigned int our_offset_align
6758 gnu_result
6763 NULL_TREE),
6764 gnu_result);
6767 gnu_result
6770 our_offset_align);
6771 }
6774 }
6775 \f
6776 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
6777 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
6778 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
6779 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
6780 for the size of a field. COMPONENT_P is true if we are being called
6781 to process the Component_Size of GNAT_OBJECT. This is used for error
6782 message handling and to indicate to use the object size of GNU_TYPE.
6783 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
6784 it means that a size of zero should be treated as an unspecified size. */
6786 static tree
6789 {
6790 Node_Id gnat_error_node;
6794 /* If a type needs strict alignment, a component of this type in
6795 a packed record cannot be packed and thus uses the type size. */
6798 else
6801 /* Find the node to use for errors. */
6808 else
6811 /* Return 0 if no size was specified, either because Esize was not Present or
6812 the specified size was zero. */
6816 /* Get the size as a tree. Give an error if a size was specified, but cannot
6817 be represented as in sizetype. */
6820 {
6825 }
6827 /* Ignore a negative size since that corresponds to our back-annotation.
6828 Also ignore a zero size unless a size clause exists. */
6832 /* The size of objects is always a multiple of a byte. */
6835 {
6839 else
6843 }
6845 /* If this is an integral type or a packed array type, the front-end has
6846 verified the size, so we need not do it here (which would entail
6847 checking against the bounds). However, if this is an aliased object, it
6848 may not be smaller than the type of the object. */
6853 /* If the object is a record that contains a template, add the size of
6854 the template to the specified size. */
6859 /* Modify the size of the type to be that of the maximum size if it has a
6860 discriminant. */
6864 /* If this is an access type or a fat pointer, the minimum size is that given
6865 by the smallest integral mode that's valid for pointers. */
6867 {
6873 ;
6876 }
6878 /* If the size of the object is a constant, the new size must not be
6879 smaller. */
6883 {
6885 post_error_ne_tree
6888 else
6895 post_error_ne_tree_2
6905 }
6908 }
6909 \f
6910 /* Similarly, but both validate and process a value of RM_Size. This
6911 routine is only called for types. */
6913 static void
6915 {
6916 /* Only give an error if a Value_Size clause was explicitly given.
6917 Otherwise, we'd be duplicating an error on the Size clause. */
6918 Node_Id gnat_attr_node
6921 tree size;
6923 /* Get the size as a tree. Do nothing if none was specified, either
6924 because RM_Size was not Present or if the specified size was zero.
6925 Give an error if a size was specified, but cannot be represented as
6926 in sizetype. */
6932 {
6935 gnat_entity);
6938 }
6940 /* Ignore a negative size since that corresponds to our back-annotation.
6941 Also ignore a zero size unless a size clause exists, a Value_Size
6942 clause exists, or this is an integer type, in which case the
6943 front end will have always set it. */
6950 /* If the old size is self-referential, get the maximum size. */
6954 /* If the size of the object is a constant, the new size must not be
6955 smaller (the front end checks this for scalar types). */
6960 {
6962 post_error_ne_tree
6967 }
6969 /* Otherwise, set the RM_Size. */
6980 }
6981 \f
6982 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
6983 If TYPE is the best type, return it. Otherwise, make a new type. We
6984 only support new integral and pointer types. BIASED_P is nonzero if
6985 we are making a biased type. */
6987 static tree
6989 {
6990 tree new_type;
6994 /* If size indicates an error, just return TYPE to avoid propagating the
6995 error. Likewise if it's too large to represent. */
7001 {
7004 /* Only do something if the type is not already the proper size and is
7005 not a packed array type. */
7017 new_type
7029 /* Do something if this is a fat pointer, in which case we
7030 may need to return the thin pointer. */
7032 return
7033 build_pointer_type
7038 /* Only do something if this is a thin pointer, in which case we
7039 may need to return the fat pointer. */
7041 return
7048 }
7051 }
7052 \f
7053 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
7054 a type or object whose present alignment is ALIGN. If this alignment is
7055 valid, return it. Otherwise, give an error and return ALIGN. */
7057 static unsigned int
7059 {
7062 Node_Id gnat_error_node;
7064 /* Don't worry about checking alignment if alignment was not specified
7065 by the source program and we already posted an error for this entity. */
7069 /* Post the error on the alignment clause if any. */
7072 else
7075 /* Within GCC, an alignment is an integer, so we must make sure a value is
7076 specified that fits in that range. Also, there is an upper bound to
7077 alignments we can support/allow. */
7088 else
7089 {
7093 }
7096 }
7098 /* Return the smallest alignment not less than SIZE. */
7100 static unsigned int
7102 {
7104 }
7105 \f
7106 /* Verify that OBJECT, a type or decl, is something we can implement
7107 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
7108 if we require atomic components. */
7110 static void
7112 {
7114 Node_Id gnat_node;
7117 tree size;
7119 /* There are three case of what OBJECT can be. It can be a type, in which
7120 case we take the size, alignment and mode from the type. It can be a
7121 declaration that was indirect, in which case the relevant values are
7122 that of the type being pointed to, or it can be a normal declaration,
7123 in which case the values are of the decl. The code below assumes that
7124 OBJECT is either a type or a decl. */
7126 {
7130 }
7132 {
7136 }
7137 else
7138 {
7142 }
7144 /* Consider all floating-point types atomic and any types that that are
7145 represented by integers no wider than a machine word. */
7152 /* For the moment, also allow anything that has an alignment equal
7153 to its size and which is smaller than a word. */
7161 {
7170 }
7175 else
7178 }
7179 \f
7180 /* Check if FTYPE1 and FTYPE2, two potentially different function type nodes,
7181 have compatible signatures so that a call using one type may be safely
7182 issued if the actual target function type is the other. Return 1 if it is
7183 the case, 0 otherwise, and post errors on the incompatibilities.
7185 This is used when an Ada subprogram is mapped onto a GCC builtin, to ensure
7186 that calls to the subprogram will have arguments suitable for the later
7187 underlying builtin expansion. */
7189 static int
7191 {
7192 /* As of now, we only perform very trivial tests and consider it's the
7193 programmer's responsibility to ensure the type correctness in the Ada
7194 declaration, as in the regular Import cases.
7196 Mismatches typically result in either error messages from the builtin
7197 expander, internal compiler errors, or in a real call sequence. This
7198 should be refined to issue diagnostics helping error detection and
7199 correction. */
7201 /* Almost fake test, ensuring a use of each argument. */
7206 }
7207 \f
7208 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new
7209 type with all size expressions that contain F updated by replacing F
7210 with R. If F is NULL_TREE, always make a new RECORD_TYPE, even if
7211 nothing has changed. */
7213 tree
7215 {
7217 tree tem;
7220 {
7226 {
7235 SET_TYPE_INDEX_TYPE
7238 }
7245 {
7259 }
7273 /* Don't know how to do these yet. */
7277 {
7292 /* If we had bounded the sizes of T by a constant, bound the sizes of
7293 NEW by the same constant. */
7303 }
7308 {
7309 tree field;
7310 bool changed_field
7317 /* Start out with no fields, make new fields, and chain them
7318 in. If we haven't actually changed the type of any field,
7319 discard everything we've done and return the old type. */
7325 {
7336 /* If this is an internal field and the type of this field is
7337 a UNION_TYPE or RECORD_TYPE with no elements, ignore it. If
7338 the type just has one element, treat that as the field.
7339 But don't do this if we are processing a QUAL_UNION_TYPE. */
7344 {
7349 {
7350 tree next_new_field
7353 /* Make sure omitting the union doesn't change
7354 the layout. */
7357 }
7358 }
7365 /* If the size of the old field was set at a constant,
7366 propagate the size in case the type's size was variable.
7367 (This occurs in the case of a variant or discriminated
7368 record with a default size used as a field of another
7369 record.) */
7378 {
7384 /* Do the substitution inside the qualifier and if we find
7385 that this field will not be present, omit it. */
7390 }
7394 else
7399 /* If this is a qualified type and this field will always be
7400 present, we are done. */
7404 }
7406 /* If this used to be a qualified union type, but we now know what
7407 field will be present, make this a normal union. */
7418 /* If the size was originally a constant use it. */
7421 {
7425 }
7428 }
7432 }
7433 }
7434 \f
7435 /* Return the "RM size" of GNU_TYPE. This is the actual number of bits
7436 needed to represent the object. */
7438 tree
7440 {
7441 /* For integer types, this is the precision. For record types, we store
7442 the size explicitly. For other types, this is just the size. */
7448 /* Return the rm_size of the actual data plus the size of the template. */
7449 return
7459 else
7461 }
7462 \f
7463 /* Return an identifier representing the external name to be used for
7464 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
7465 and the specified suffix. */
7467 tree
7469 {
7478 /* A variable using the Stdcall convention (meaning we are running
7479 on a Windows box) live in a DLL. Here we adjust its name to use
7480 the jump-table, the _imp__NAME contains the address for the NAME
7481 variable. */
7484 {
7491 }
7494 }
7496 /* Return the name to be used for GNAT_ENTITY. If a type, create a
7497 fully-qualified name, possibly with type information encoding.
7498 Otherwise, return the name. */
7500 tree
7502 {
7505 }
7507 /* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
7508 string, return a new IDENTIFIER_NODE that is the concatenation of
7509 the name in GNU_ID and SUFFIX. */
7511 tree
7513 {
7521 }