| blob | c57e145ff61c308b535257a0f5cd466f5a5fdaf7 |
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 /* Convention_Stdcall should be processed in a specific way on Windows targets
57 only. The macro below is a helper to avoid having to check for a Windows
58 specific attribute throughout this unit. */
60 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
61 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
62 #else
63 #define Has_Stdcall_Convention(E) (0)
64 #endif
66 struct incomplete
67 {
69 tree old_type;
70 Entity_Id full_type;
71 };
73 /* These variables are used to defer recursively expanding incomplete types
74 while we are processing an array, a record or a subprogram type. */
78 /* This variable is used to delay expanding From_With_Type types until the
79 end of the spec. */
82 /* These variables are used to defer finalizing types. The element of the
83 list is the TYPE_DECL associated with the type. */
87 /* A hash table used to cache the result of annotate_value. */
120 /* Given GNAT_ENTITY, an entity in the incoming GNAT tree, return a
121 GCC type corresponding to that entity. GNAT_ENTITY is assumed to
122 refer to an Ada type. */
124 tree
126 {
127 tree gnu_decl;
129 /* The back end never attempts to annotate generic types */
133 /* Convert the ada entity type into a GCC TYPE_DECL node. */
137 }
138 \f
139 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
140 entity, this routine returns the equivalent GCC tree for that entity
141 (an ..._DECL node) and associates the ..._DECL node with the input GNAT
142 defining identifier.
144 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
145 initial value (in GCC tree form). This is optional for variables.
146 For renamed entities, GNU_EXPR gives the object being renamed.
148 DEFINITION is nonzero if this call is intended for a definition. This is
149 used for separate compilation where it necessary to know whether an
150 external declaration or a definition should be created if the GCC equivalent
151 was not created previously. The value of 1 is normally used for a nonzero
152 DEFINITION, but a value of 2 is used in special circumstances, defined in
153 the code. */
155 tree
157 {
159 tree gnu_entity_id;
161 /* Contains the gnu XXXX_DECL tree node which is equivalent to the input
162 GNAT tree. This node will be associated with the GNAT node by calling
163 the save_gnu_tree routine at the end of the `switch' statement. */
165 /* true if we have already saved gnu_decl as a gnat association. */
167 /* Nonzero if we incremented defer_incomplete_level. */
169 /* Nonzero if we incremented force_global. */
171 /* Nonzero if we should check to see if elaborated during processing. */
173 /* Nonzero if we made GNU_DECL and its type here. */
179 Entity_Id gnat_temp;
180 unsigned int esize
190 bool imported_p
194 /* Since a use of an Itype is a definition, process it as such if it
195 is not in a with'ed unit. */
200 {
201 /* Ensure that we are in a subprogram mentioned in the Scope
202 chain of this entity, our current scope is global,
203 or that we encountered a task or entry (where we can't currently
204 accurately check scoping). */
207 {
210 }
214 {
219 gnat_temp
231 && (current_function_decl
233 {
236 }
237 }
239 /* This abort means the entity "gnat_entity" has an incorrect scope,
240 i.e. that its scope does not correspond to the subprogram in which
241 it is declared */
243 }
245 /* If this is entity 0, something went badly wrong. */
248 /* If we've already processed this entity, return what we got last time.
249 If we are defining the node, we should not have already processed it.
250 In that case, we will abort below when we try to save a new GCC tree for
251 this object. We also need to handle the case of getting a dummy type
252 when a Full_View exists. */
256 {
263 {
269 }
272 }
274 /* If this is a numeric or enumeral type, or an access type, a nonzero
275 Esize must be specified unless it was specified by the programmer. */
284 /* Likewise, RM_Size must be specified for all discrete and fixed-point
285 types. */
289 /* Get the name of the entity and set up the line number and filename of
290 the original definition for use in any decl we make. */
294 /* If we get here, it means we have not yet done anything with this
295 entity. If we are not defining it here, it must be external,
296 otherwise we should have defined it already. */
303 /* For cases when we are not defining (i.e., we are referencing from
304 another compilation unit) Public entities, show we are at global level
305 for the purpose of computing scopes. Don't do this for components or
306 discriminants since the relevant test is whether or not the record is
307 being defined. But do this for Imported functions or procedures in
308 all cases. */
316 /* Handle any attributes directly attached to the entity. */
320 /* Machine_Attributes on types are expected to be propagated to subtypes.
321 The corresponding Gigi_Rep_Items are only attached to the first subtype
322 though, so we handle the propagation here. */
329 {
331 /* If this is a use of a deferred constant, get its full
332 declaration. */
334 {
339 }
341 /* If we have an external constant that we are not defining, get the
342 expression that is was defined to represent. We may throw that
343 expression away later if it is not a constant. Do not retrieve the
344 expression if it is an aggregate or allocator, because in complex
345 instantiation contexts it may not be expanded */
355 /* Ignore deferred constant definitions; they are processed fully in the
356 front-end. For deferred constant references get the full definition.
357 On the other hand, constants that are renamings are handled like
358 variable renamings. If No_Initialization is set, this is not a
359 deferred constant but a constant whose value is built manually. */
363 {
367 }
370 {
375 }
380 /* We used to special case VMS exceptions here to directly map them to
381 their associated condition code. Since this code had to be masked
382 dynamically to strip off the severity bits, this caused trouble in
383 the GCC/ZCX case because the "type" pointers we store in the tables
384 have to be static. We now don't special case here anymore, and let
385 the regular processing take place, which leaves us with a regular
386 exception data object for VMS exceptions too. The condition code
387 mapping is taken care of by the front end and the bitmasking by the
388 runtime library. */
393 {
394 /* The GNAT record where the component was defined. */
397 /* If the variable is an inherited record component (in the case of
398 extended record types), just return the inherited entity, which
399 must be a FIELD_DECL. Likewise for discriminants.
400 For discriminants of untagged records which have explicit
401 stored discriminants, return the entity for the corresponding
402 stored discriminant. Also use Original_Record_Component
403 if the record has a private extension. */
407 {
408 gnu_decl
413 }
415 /* If the enclosing record has explicit stored discriminants,
416 then it is an untagged record. If the Corresponding_Discriminant
417 is not empty then this must be a renamed discriminant and its
418 Original_Record_Component must point to the corresponding explicit
419 stored discriminant (i.e., we should have taken the previous
420 branch). */
424 {
425 /* A tagged record has no explicit stored discriminants. */
429 gnu_decl
434 }
438 {
443 }
445 /* If the enclosing record has explicit stored discriminants,
446 then it is an untagged record. If the Corresponding_Discriminant
447 is not empty then this must be a renamed discriminant and its
448 Original_Record_Component must point to the corresponding explicit
449 stored discriminant (i.e., we should have taken the first
450 branch). */
457 /* Otherwise, if we are not defining this and we have no GCC type
458 for the containing record, make one for it. Then we should
459 have made our own equivalent. */
461 {
462 /* ??? If this is in a record whose scope is a protected
463 type and we have an Original_Record_Component, use it.
464 This is a workaround for major problems in protected type
465 handling. */
472 {
473 gnu_decl
479 }
485 }
487 else
488 /* Here we have no GCC type and this is a reference rather than a
489 definition. This should never happen. Most likely the cause is a
490 reference before declaration in the gnat tree for gnat_entity. */
492 }
498 /* Simple variables, loop variables, Out parameters, and exceptions. */
499 object:
500 {
502 bool const_flag
516 {
520 else
522 }
524 /* Get the type after elaborating the renamed object. */
527 /* For a debug renaming declaration, build a pure debug entity. */
529 {
530 rtx addr;
532 /* The (MEM (CONST (0))) pattern is prescribed by STABS. */
535 else
540 }
542 /* If this is a loop variable, its type should be the base type.
543 This is because the code for processing a loop determines whether
544 a normal loop end test can be done by comparing the bounds of the
545 loop against those of the base type, which is presumed to be the
546 size used for computation. But this is not correct when the size
547 of the subtype is smaller than the type. */
551 /* Reject non-renamed objects whose types are unconstrained arrays or
552 any object whose type is a dummy type or VOID_TYPE. */
558 {
561 force_global--;
563 }
565 /* If an alignment is specified, use it if valid. Note that
566 exceptions are objects but don't have alignments. We must do this
567 before we validate the size, since the alignment can affect the
568 size. */
570 {
576 }
578 /* If we are defining the object, see if it has a Size value and
579 validate it if so. If we are not defining the object and a Size
580 clause applies, simply retrieve the value. We don't want to ignore
581 the clause and it is expected to have been validated already. Then
582 get the new type, if any. */
591 {
592 gnu_type
598 }
600 /* If this object has self-referential size, it must be a record with
601 a default value. We are supposed to allocate an object of the
602 maximum size in this case unless it is a constant with an
603 initializing expression, in which case we can get the size from
604 that. Note that the resulting size may still be a variable, so
605 this may end up with an indirect allocation. */
609 {
611 gnu_size
612 = SUBSTITUTE_PLACEHOLDER_IN_EXPR
615 /* We may have no GNU_EXPR because No_Initialization is
616 set even though there's an Expression. */
621 gnu_size
623 (Etype
625 else
626 {
629 }
630 }
632 /* If the size is zero bytes, make it one byte since some linkers have
633 trouble with zero-sized objects. If the object will have a
634 template, that will make it nonzero so don't bother. Also avoid
635 doing that for an object renaming or an object with an address
636 clause, as we would lose useful information on the view size
637 (e.g. for null array slices) and we are not allocating the object
638 here anyway. */
647 /* If this is an atomic object with no specified size and alignment,
648 but where the size of the type is a constant, set the alignment to
649 the smallest not less than the size, or to the biggest meaningful
650 alignment, whichever is smaller. */
653 {
656 BIGGEST_ALIGNMENT))
658 else
660 }
662 /* If the object is set to have atomic components, find the component
663 type and validate it.
665 ??? Note that we ignore Has_Volatile_Components on objects; it's
666 not at all clear what to do in that case. */
669 {
678 }
680 /* Now check if the type of the object allows atomic access. Note
681 that we must test the type, even if this object has size and
682 alignment to allow such access, because we will be going
683 inside the padded record to assign to the object. We could fix
684 this by always copying via an intermediate value, but it's not
685 clear it's worth the effort. */
689 /* If this is an aliased object with an unconstrained nominal subtype,
690 make a type that includes the template. */
694 {
695 tree gnu_fat
698 gnu_type
702 }
704 #ifdef MINIMUM_ATOMIC_ALIGNMENT
705 /* If the size is a constant and no alignment is specified, force
706 the alignment to be the minimum valid atomic alignment. The
707 restriction on constant size avoids problems with variable-size
708 temporaries; if the size is variable, there's no issue with
709 atomic access. Also don't do this for a constant, since it isn't
710 necessary and can interfere with constant replacement. Finally,
711 do not do it for Out parameters since that creates an
712 size inconsistency with In parameters. */
721 #endif
723 /* Make a new type with the desired size and alignment, if needed. */
727 /* Make a volatile version of this object's type if we are to make
728 the object volatile. We also interpret 13.3(19) conservatively
729 and disallow any optimizations for an object covered by it. */
732 /* Exclude exported constants created by the compiler,
733 which should boil down to static dispatch tables and
734 make it possible to put them in read-only memory. */
743 /* If this is a renaming, avoid as much as possible to create a new
744 object. However, in several cases, creating it is required.
745 This processing needs to be applied to the raw expression so
746 as to make it more likely to rename the underlying object. */
748 {
751 /* If the renamed object had padding, strip off the reference
752 to the inner object and reset our type. */
755 == RECORD_TYPE
757 /* Strip useless conversions around the object. */
759 {
762 }
764 /* Case 1: If this is a constant renaming stemming from a function
765 call, treat it as a normal object whose initial value is what
766 is being renamed. RM 3.3 says that the result of evaluating a
767 function call is a constant object. As a consequence, it can
768 be the inner object of a constant renaming. In this case, the
769 renaming must be fully instantiated, i.e. it cannot be a mere
770 reference to (part of) an existing object. */
772 {
778 }
780 /* Otherwise, see if we can proceed with a stabilized version of
781 the renamed entity or if we need to make a new object. */
783 {
787 /* Case 2: If the renaming entity need not be materialized and
788 the renamed expression is something we can stabilize, use
789 that for the renaming. At the global level, we can only do
790 this if we know no SAVE_EXPRs need be made, because the
791 expression we return might be used in arbitrary conditional
792 branches so we must force the SAVE_EXPRs evaluation
793 immediately and this requires a function context. */
798 {
799 maybe_stable_expr
803 {
805 /* ??? No DECL_EXPR is created so we need to mark
806 the expression manually lest it is shared. */
812 }
814 /* The stabilization failed. Keep maybe_stable_expr
815 untouched here to let the pointer case below know
816 about that failure. */
817 }
819 /* Case 3: If this is a constant renaming and creating a
820 new object is allowed and cheap, treat it as a normal
821 object whose initial value is what is being renamed. */
823 ;
825 /* Case 4: Make this into a constant pointer to the object we
826 are to rename and attach the object to the pointer if it is
827 something we can stabilize.
829 From the proper scope, attached objects will be referenced
830 directly instead of indirectly via the pointer to avoid
831 subtle aliasing problems with non-addressable entities.
832 They have to be stable because we must not evaluate the
833 variables in the expression every time the renaming is used.
834 The pointer is called a "renaming" pointer in this case.
836 In the rare cases where we cannot stabilize the renamed
837 object, we just make a "bare" pointer, and the renamed
838 entity is always accessed indirectly through it. */
839 else
840 {
845 /* If the previous attempt at stabilizing failed, there
846 is no point in trying again and we reuse the result
847 without attaching it to the pointer. In this case it
848 will only be used as the initializing expression of
849 the pointer and thus needs no special treatment with
850 regard to multiple evaluations. */
852 ;
854 /* Otherwise, try to stabilize and attach the expression
855 to the pointer if the stabilization succeeds.
857 Note that this might introduce SAVE_EXPRs and we don't
858 check whether we're at the global level or not. This
859 is fine since we are building a pointer initializer and
860 neither the pointer nor the initializing expression can
861 be accessed before the pointer elaboration has taken
862 place in a correct program.
864 These SAVE_EXPRs will be evaluated at the right place
865 by either the evaluation of the initializer for the
866 non-global case or the elaboration code for the global
867 case, and will be attached to the elaboration procedure
868 in the latter case. */
869 else
870 {
871 maybe_stable_expr
877 /* Attaching is actually performed downstream, as soon
878 as we have a VAR_DECL for the pointer we make. */
879 }
881 gnu_expr
886 }
887 }
888 }
890 /* If this is an aliased object whose nominal subtype is unconstrained,
891 the object is a record that contains both the template and
892 the object. If there is an initializer, it will have already
893 been converted to the right type, but we need to create the
894 template if there is no initializer. */
898 /* Beware that padding might have been introduced
899 via maybe_pad_type above. */
902 == RECORD_TYPE
903 && TYPE_CONTAINS_TEMPLATE_P
906 {
907 tree template_field
912 gnu_expr
913 = gnat_build_constructor
915 tree_cons
919 NULL_TREE),
920 NULL_TREE));
921 }
923 /* Convert the expression to the type of the object except in the
924 case where the object's type is unconstrained or the object's type
925 is a padded record whose field is of self-referential size. In
926 the former case, converting will generate unnecessary evaluations
927 of the CONSTRUCTOR to compute the size and in the latter case, we
928 want to only copy the actual data. */
934 && (CONTAINS_PLACEHOLDER_P
938 /* If this is a pointer and it does not have an initializing
939 expression, initialize it to NULL, unless the object is
940 imported. */
946 /* If we are defining the object and it has an Address clause we must
947 get the address expression from the saved GCC tree for the
948 object if the object has a Freeze_Node. Otherwise, we elaborate
949 the address expression here since the front-end has guaranteed
950 in that case that the elaboration has no effects. Note that
951 only the latter mechanism is currently in use. */
953 {
954 tree gnu_address
960 /* Ignore the size. It's either meaningless or was handled
961 above. */
963 /* Convert the type of the object to a reference type that can
964 alias everything as per 13.3(19). */
965 gnu_type
971 /* If we don't have an initializing expression for the underlying
972 variable, the initializing expression for the pointer is the
973 specified address. Otherwise, we have to make a COMPOUND_EXPR
974 to assign both the address and the initial value. */
977 else
978 gnu_expr
980 build_binary_op
983 gnu_address),
984 gnu_expr),
985 gnu_address);
986 }
988 /* If it has an address clause and we are not defining it, mark it
989 as an indirect object. Likewise for Stdcall objects that are
990 imported. */
994 {
995 /* Convert the type of the object to a reference type that can
996 alias everything as per 13.3(19). */
997 gnu_type
1002 /* No point in taking the address of an initializing expression
1003 that isn't going to be used. */
1006 }
1008 /* If we are at top level and this object is of variable size,
1009 make the actual type a hidden pointer to the real type and
1010 make the initializer be a memory allocation and initialization.
1011 Likewise for objects we aren't defining (presumed to be
1012 external references from other packages), but there we do
1013 not set up an initialization.
1015 If the object's size overflows, make an allocator too, so that
1016 Storage_Error gets raised. Note that we will never free
1017 such memory, so we presume it never will get allocated. */
1022 || (gnu_size
1026 {
1032 /* In case this was a aliased object whose nominal subtype is
1033 unconstrained, the pointer above will be a thin pointer and
1034 build_allocator will automatically make the template.
1036 If we have a template initializer only (that we made above),
1037 pretend there is none and rely on what build_allocator creates
1038 again anyway. Otherwise (if we have a full initializer), get
1039 the data part and feed that to build_allocator.
1041 If we are elaborating a mutable object, tell build_allocator to
1042 ignore a possibly simpler size from the initializer, if any, as
1043 we must allocate the maximum possible size in this case. */
1046 {
1051 {
1052 gnu_alloc_type
1059 else
1060 gnu_expr
1061 = build_component_ref
1065 }
1071 gnat_entity);
1075 }
1076 else
1077 {
1080 }
1081 }
1083 /* If this object would go into the stack and has an alignment larger
1084 than the largest stack alignment the back-end can honor, resort to
1085 a variable of "aligning type". */
1088 {
1089 /* Create the new variable. No need for extra room before the
1090 aligned field as this is in automatic storage. */
1091 tree gnu_new_type
1095 tree gnu_new_var
1100 /* Initialize the aligned field if we have an initializer. */
1102 add_stmt_with_node
1104 build_component_ref
1107 gnu_expr),
1108 gnat_entity);
1110 /* And setup this entity as a reference to the aligned field. */
1112 gnu_expr
1113 = build_unary_op
1121 }
1127 /* Convert the expression to the type of the object except in the
1128 case where the object's type is unconstrained or the object's type
1129 is a padded record whose field is of self-referential size. In
1130 the former case, converting will generate unnecessary evaluations
1131 of the CONSTRUCTOR to compute the size and in the latter case, we
1132 want to only copy the actual data. */
1138 && (CONTAINS_PLACEHOLDER_P
1142 /* If this name is external or there was a name specified, use it,
1143 unless this is a VMS exception object since this would conflict
1144 with the symbol we need to export in addition. Don't use the
1145 Interface_Name if there is an address clause (see CD30005). */
1154 /* If this is constant initialized to a static constant and the
1155 object has an aggregate type, force it to be statically
1156 allocated. */
1172 {
1175 {
1178 }
1179 }
1186 STACK_CHECK_MAX_VAR_SIZE))))
1191 gnat_entity);
1193 /* If this is a public constant or we're not optimizing and we're not
1194 making a VAR_DECL for it, make one just for export or debugger use.
1195 Likewise if the address is taken or if either the object or type is
1196 aliased. Make an external declaration for a reference, unless this
1197 is a Standard entity since there no real symbol at the object level
1198 for these. */
1206 {
1207 tree gnu_corr_var
1211 gnat_entity);
1214 }
1216 /* If this is declared in a block that contains a block with an
1217 exception handler, we must force this variable in memory to
1218 suppress an invalid optimization. */
1225 /* Back-annotate Alignment and Esize of the object if not already
1226 known, except for when the object is actually a pointer to the
1227 real object, since alignment and size of a pointer don't have
1228 anything to do with those of the designated object. Note that
1229 we pick the values of the type, not those of the object, to
1230 shield ourselves from low-level platform-dependent adjustments
1231 like alignment promotion. This is both consistent with all the
1232 treatment above, where alignment and size are set on the type of
1233 the object and not on the object directly, and makes it possible
1234 to support confirming representation clauses in all cases. */
1241 {
1242 tree gnu_back_size;
1246 gnu_back_size
1248 else
1252 }
1253 }
1257 /* Return a TYPE_DECL for "void" that we previously made. */
1262 /* A special case, for the types Character and Wide_Character in
1263 Standard, we do not list all the literals. So if the literals
1264 are not specified, make this an unsigned type. */
1266 {
1270 /* Set the TYPE_STRING_FLAG for Ada Character and
1271 Wide_Character types. This is needed by the dwarf-2 debug writer to
1272 distinguish between unsigned integer types and character types. */
1275 }
1277 /* Normal case of non-character type, or non-Standard character type */
1278 {
1279 /* Here we have a list of enumeral constants in First_Literal.
1280 We make a CONST_DECL for each and build into GNU_LITERAL_LIST
1281 the list to be places into TYPE_FIELDS. Each node in the list
1282 is a TREE_LIST node whose TREE_VALUE is the literal name
1283 and whose TREE_PURPOSE is the value of the literal.
1285 Esize contains the number of bits needed to represent the enumeral
1286 type, Type_Low_Bound also points to the first literal and
1287 Type_High_Bound points to the last literal. */
1289 Entity_Id gnat_literal;
1294 else
1302 {
1304 gnu_type);
1305 tree gnu_literal
1313 }
1317 /* Note that the bounds are updated at the end of this function
1318 because to avoid an infinite recursion when we get the bounds of
1319 this type, since those bounds are objects of this type. */
1320 }
1326 /* For integer types, just make a signed type the appropriate number
1327 of bits. */
1332 /* For modular types, make the unsigned type of the proper number of
1333 bits and then set up the modulus, if required. */
1334 {
1336 tree gnu_modulus;
1342 /* Find the smallest mode at least ESIZE bits wide and make a class
1343 using that mode. */
1348 ;
1354 /* Get the modulus in this type. If it overflows, assume it is because
1355 it is equal to 2**Esize. Note that there is no overflow checking
1356 done on unsigned type, so we detect the overflow by looking for
1357 a modulus of zero, which is otherwise invalid. */
1361 {
1366 }
1368 /* If we have to set TYPE_PRECISION different from its natural value,
1369 make a subtype to do do. Likewise if there is a modulus and
1370 it is not one greater than TYPE_MAX_VALUE. */
1374 {
1391 }
1392 }
1401 /* For integral subtypes, we make a new INTEGER_TYPE. Note
1402 that we do not want to call build_range_type since we would
1403 like each subtype node to be distinct. This will be important
1404 when memory aliasing is implemented.
1406 The TREE_TYPE field of the INTEGER_TYPE we make points to the
1407 parent type; this fact is used by the arithmetic conversion
1408 functions.
1410 We elaborate the Ancestor_Subtype if it is not in the current
1411 unit and one of our bounds is non-static. We do this to ensure
1412 consistent naming in the case where several subtypes share the same
1413 bounds by always elaborating the first such subtype first, thus
1414 using its name. */
1426 {
1429 }
1437 gnat_entity,
1444 gnat_entity,
1448 /* One of the above calls might have caused us to be elaborated,
1449 so don't blow up if so. */
1451 {
1454 }
1459 /* This should be an unsigned type if the lower bound is constant
1460 and non-negative or if the base type is unsigned; a signed type
1461 otherwise. */
1471 /* Inherit our alias set from what we're a subtype of. Subtypes
1472 are not different types and a pointer can designate any instance
1473 within a subtype hierarchy. */
1476 /* If the type we are dealing with is to represent a packed array,
1477 we need to have the bits left justified on big-endian targets
1478 and right justified on little-endian targets. We also need to
1479 ensure that when the value is read (e.g. for comparison of two
1480 such values), we only get the good bits, since the unused bits
1481 are uninitialized. Both goals are accomplished by wrapping the
1482 modular value in an enclosing struct. */
1484 {
1486 tree gnu_field;
1496 /* Create a stripped-down declaration of the original type, mainly
1497 for debugging. */
1501 /* Don't notify the field as "addressable", since we won't be taking
1502 it's address and it would prevent create_field_decl from making a
1503 bitfield. */
1512 }
1517 /* If this is a VAX floating-point type, use an integer of the proper
1518 size. All the operations will be handled with ASM statements. */
1520 {
1525 sizetype));
1527 }
1529 /* The type of the Low and High bounds can be our type if this is
1530 a type from Standard, so set them at the end of the function. */
1538 {
1541 }
1543 {
1570 /* One of the above calls might have caused us to be elaborated,
1571 so don't blow up if so. */
1573 {
1576 }
1580 /* Inherit our alias set from what we're a subtype of, as for
1581 integer subtypes. */
1583 }
1586 /* Array and String Types and Subtypes
1588 Unconstrained array types are represented by E_Array_Type and
1589 constrained array types are represented by E_Array_Subtype. There
1590 are no actual objects of an unconstrained array type; all we have
1591 are pointers to that type.
1593 The following fields are defined on array types and subtypes:
1595 Component_Type Component type of the array.
1596 Number_Dimensions Number of dimensions (an int).
1597 First_Index Type of first index. */
1601 {
1607 int firstdim
1609 int nextdim
1615 tree gnu_max_size_unit;
1617 Entity_Id gnat_ind_subtype;
1618 Entity_Id gnat_ind_base_subtype;
1619 tree gnu_template_reference;
1620 tree tem;
1625 /* Make a node for the array. If we are not defining the array
1626 suppress expanding incomplete types. */
1632 /* Build the fat pointer type. Use a "void *" object instead of
1633 a pointer to the array type since we don't have the array type
1634 yet (it will reference the fat pointer via the bounds). */
1637 ptr_void_type_node,
1640 gnu_ptr_template,
1643 /* Make sure we can put this into a register. */
1646 /* Do not finalize this record type since the types of its fields
1647 are still incomplete at this point. */
1651 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1652 is the fat pointer. This will be used to access the individual
1653 fields once we build them. */
1657 gnu_template_reference
1661 /* Now create the GCC type for each index and add the fields for
1662 that index to the template. */
1664 gnat_ind_base_subtype
1670 {
1672 tree gnu_ind_subtype
1674 tree gnu_base_subtype
1676 tree gnu_base_min
1678 tree gnu_base_max
1682 /* Make the FIELD_DECLs for the minimum and maximum of this
1683 type and then make extractions of that field from the
1684 template. */
1687 gnu_ind_subtype,
1691 gnu_ind_subtype,
1700 /* We can't use build_component_ref here since the template
1701 type isn't complete yet. */
1704 NULL_TREE);
1707 NULL_TREE);
1710 /* Make a range type with the new ranges, but using
1711 the Ada subtype. Then we convert to sizetype. */
1717 gnat_entity);
1718 /* Update the maximum size of the array, in elements. */
1719 gnu_max_size
1723 gnu_base_min)));
1727 }
1730 gnu_template_fields
1733 /* Install all the fields into the template. */
1737 /* Now make the array of arrays and update the pointer to the array
1738 in the fat pointer. Note that it is the first field. */
1741 /* Get and validate any specified Component_Size, but if Packed,
1742 ignore it since the front end will have taken care of it. */
1743 gnu_comp_size
1745 gnat_entity,
1753 /* If the component type is a RECORD_TYPE that has a self-referential
1754 size, use the maxium size. */
1760 {
1761 tree orig_tem;
1766 /* If a padding record was made, declare it now since it will
1767 never be declared otherwise. This is necessary in order to
1768 ensure that its subtrees are properly marked. */
1771 gnat_entity);
1772 }
1778 /* If Component_Size is not already specified, annotate it with the
1779 size of the component. */
1789 gnu_max_size),
1793 {
1798 }
1800 /* If an alignment is specified, use it if valid. But ignore it for
1801 types that represent the unpacked base type for packed arrays. If
1802 the alignment was requested with an explicit user alignment clause,
1803 state so. */
1806 {
1813 }
1819 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
1820 corresponding fat pointer. */
1827 /* If the maximum size doesn't overflow, use it. */
1842 /* Give the fat pointer type a name. */
1847 /* Create the type to be used as what a thin pointer designates: an
1848 record type for the object and its template with the field offsets
1849 shifted to have the template at a negative offset. */
1857 /* Give the thin pointer type a name. */
1861 gnat_entity);
1862 }
1868 /* This is the actual data type for array variables. Multidimensional
1869 arrays are implemented in the gnu tree as arrays of arrays. Note
1870 that for the moment arrays which have sparse enumeration subtypes as
1871 index components create sparse arrays, which is obviously space
1872 inefficient but so much easier to code for now.
1874 Also note that the subtype never refers to the unconstrained
1875 array type, which is somewhat at variance with Ada semantics.
1877 First check to see if this is simply a renaming of the array
1878 type. If so, the result is the array type. */
1883 else
1884 {
1887 int first_dim
1890 int next_dim
1892 Entity_Id gnat_ind_subtype;
1893 Entity_Id gnat_ind_base_subtype;
1898 tree gnu_max_size_unit;
1902 /* First create the gnu types for each index. Create types for
1903 debugging information to point to the index types if the
1904 are not integer types, have variable bounds, or are
1905 wider than sizetype. */
1908 gnat_ind_base_subtype
1914 {
1915 tree gnu_index_subtype
1917 tree gnu_min
1919 tree gnu_max
1921 tree gnu_base_subtype
1923 tree gnu_base_min
1925 tree gnu_base_max
1928 tree gnu_base_base_min
1930 tree gnu_base_base_max
1932 tree gnu_high;
1933 tree gnu_this_max;
1935 /* If the minimum and maximum values both overflow in
1936 SIZETYPE, but the difference in the original type
1937 does not overflow in SIZETYPE, ignore the overflow
1938 indications. */
1946 && (!TREE_OVERFLOW
1950 {
1953 }
1955 /* Similarly, if the range is null, use bounds of 1..0 for
1956 the sizetype bounds. */
1968 /* Now compute the size of this bound. We need to provide
1969 GCC with an upper bound to use but have to deal with the
1970 "superflat" case. There are three ways to do this. If we
1971 can prove that the array can never be superflat, we can
1972 just use the high bound of the index subtype. If we can
1973 prove that the low bound minus one can't overflow, we
1974 can do this as MAX (hb, lb - 1). Otherwise, we have to use
1975 the expression hb >= lb ? hb : lb - 1. */
1978 /* See if the base array type is already flat. If it is, we
1979 are probably compiling an ACVC test, but it will cause the
1980 code below to malfunction if we don't handle it specially. */
1988 /* If gnu_high is now an integer which overflowed, the array
1989 cannot be superflat. */
1996 else
1997 gnu_high
1998 = build_cond_expr
2005 gnat_entity);
2007 /* Also compute the maximum size of the array. Here we
2008 see if any constraint on the index type of the base type
2009 can be used in the case of self-referential bound on
2010 the index type of the subtype. We look for a non-"infinite"
2011 and non-self-referential bound from any type involved and
2012 handle each bound separately. */
2041 gnu_this_max
2045 gnu_base_min)),
2046 size_zero_node);
2052 gnu_max_size
2066 }
2068 /* Then flatten: create the array of arrays. */
2072 /* One of the above calls might have caused us to be elaborated,
2073 so don't blow up if so. */
2075 {
2078 }
2080 /* Get and validate any specified Component_Size, but if Packed,
2081 ignore it since the front end will have taken care of it. */
2082 gnu_comp_size
2084 gnat_entity,
2089 /* If the component type is a RECORD_TYPE that has a self-referential
2090 size, use the maxium size. */
2096 {
2097 tree orig_gnu_type;
2103 /* If a padding record was made, declare it now since it will
2104 never be declared otherwise. This is necessary in order to
2105 ensure that its subtrees are properly marked. */
2109 }
2123 {
2128 }
2130 /* If we are at file level and this is a multi-dimensional array, we
2131 need to make a variable corresponding to the stride of the
2132 inner dimensions. */
2134 {
2136 tree gnu_arr_type;
2142 {
2150 /* ??? For now, store the size as a multiple of the
2151 alignment of the element type in bytes so that we
2152 can see the alignment from the tree. */
2154 = build_binary_op
2156 elaborate_expression_1
2166 /* ??? create_type_decl is not invoked on the inner types so
2167 the MULT_EXPR node built above will never be marked. */
2169 }
2170 }
2172 /* If we need to write out a record type giving the names of
2173 the bounds, do it now. */
2175 {
2178 tree gnu_field;
2184 {
2185 tree gnu_type_name
2192 integer_type_node,
2193 gnu_bound_rec_type,
2197 }
2201 }
2208 /* If our size depends on a placeholder and the maximum size doesn't
2209 overflow, use it. */
2216 {
2222 }
2224 /* Set our alias set to that of our base type. This gives all
2225 array subtypes the same alias set. */
2227 }
2229 /* If this is a packed type, make this type the same as the packed
2230 array type, but do some adjusting in the type first. */
2233 {
2234 Entity_Id gnat_index;
2235 tree gnu_inner_type;
2237 /* First finish the type we had been making so that we output
2238 debugging information for it */
2239 gnu_type
2242 | (TYPE_QUAL_VOLATILE
2250 /* Save it as our equivalent in case the call below elaborates
2251 this type again. */
2266 /* We need to point the type we just made to our index type so
2267 the actual bounds can be put into a template. */
2273 {
2275 {
2276 /* The TYPE_ACTUAL_BOUNDS field is also used for the modulus.
2277 If it is, we need to make another type. */
2279 {
2280 tree gnu_subtype;
2297 }
2300 }
2306 SET_TYPE_ACTUAL_BOUNDS
2313 SET_TYPE_ACTUAL_BOUNDS
2320 }
2321 }
2323 /* Abort if packed array with no packed array type field set. */
2324 else
2330 /* Create the type for a string literal. */
2331 {
2332 Entity_Id gnat_full_type
2337 tree gnu_string_array_type
2339 tree gnu_string_index_type
2342 tree gnu_lower_bound
2347 tree gnu_upper_bound
2349 gnu_lower_bound,
2351 tree gnu_range_type
2354 tree gnu_index_type
2361 gnu_type
2363 gnu_index_type);
2365 }
2368 /* Record Types and Subtypes
2370 The following fields are defined on record types:
2372 Has_Discriminants True if the record has discriminants
2373 First_Discriminant Points to head of list of discriminants
2374 First_Entity Points to head of list of fields
2375 Is_Tagged_Type True if the record is tagged
2377 Implementation of Ada records and discriminated records:
2379 A record type definition is transformed into the equivalent of a C
2380 struct definition. The fields that are the discriminants which are
2381 found in the Full_Type_Declaration node and the elements of the
2382 Component_List found in the Record_Type_Definition node. The
2383 Component_List can be a recursive structure since each Variant of
2384 the Variant_Part of the Component_List has a Component_List.
2386 Processing of a record type definition comprises starting the list of
2387 field declarations here from the discriminants and the calling the
2388 function components_to_record to add the rest of the fields from the
2389 component list and return the gnu type node. The function
2390 components_to_record will call itself recursively as it traverses
2391 the tree. */
2395 {
2396 gnu_type
2397 = build_complex_type
2398 (get_unpadded_type
2401 (Component_List
2402 (Type_Definition
2406 }
2408 {
2411 Entity_Id gnat_field;
2412 tree gnu_field;
2414 tree gnu_get_parent;
2415 /* Set PACKED in keeping with gnat_to_gnu_field. */
2416 int packed
2428 bool is_extension
2432 /* See if all fields have a rep clause. Stop when we find one
2433 that doesn't. */
2442 /* If this is a record extension, go a level further to find the
2443 record definition. Also, verify we have a Parent_Subtype. */
2445 {
2452 }
2454 /* Make a node for the record. If we are not defining the record,
2455 suppress expanding incomplete types. */
2463 /* If both a size and rep clause was specified, put the size in
2464 the record type now so that it can get the proper mode. */
2468 /* Always set the alignment here so that it can be used to
2469 set the mode, if it is making the alignment stricter. If
2470 it is invalid, it will be checked again below. If this is to
2471 be Atomic, choose a default alignment of a word unless we know
2472 the size and it's smaller. */
2479 /* If a type needs strict alignment, the minimum size will be the
2480 type size instead of the RM size (see validate_size). Cap the
2481 alignment, lest it causes this type size to become too large. */
2484 {
2488 }
2489 else
2492 /* If we have a Parent_Subtype, make a field for the parent. If
2493 this record has rep clauses, force the position to zero. */
2495 {
2497 tree gnu_parent;
2499 /* A major complexity here is that the parent subtype will
2500 reference our discriminants in its Discriminant_Constraint
2501 list. But those must reference the parent component of this
2502 record which is of the parent subtype we have not built yet!
2503 To break the circle we first build a dummy COMPONENT_REF which
2504 represents the "get to the parent" operation and initialize
2505 each of those discriminants to a COMPONENT_REF of the above
2506 dummy parent referencing the corresponding discriminant of the
2507 base type of the parent subtype. */
2511 void_type_node),
2512 NULL_TREE);
2519 save_gnu_tree
2523 gnu_get_parent,
2526 NULL_TREE),
2529 /* Then we build the parent subtype. */
2532 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
2533 initially built. The discriminants must reference the fields
2534 of the parent subtype and not those of its base type for the
2535 placeholder machinery to properly work. */
2541 {
2551 }
2553 /* The "get to the parent" COMPONENT_REF must be given its
2554 proper type... */
2557 /* ...and reference the _parent field of this record. */
2558 gnu_field_list
2566 }
2568 /* Make the fields for the discriminants and put them into the record
2569 unless it's an Unchecked_Union. */
2574 {
2575 /* If this is a record extension and this discriminant
2576 is the renaming of another discriminant, we've already
2577 handled the discriminant above. */
2582 gnu_field
2585 /* Make an expression using a PLACEHOLDER_EXPR from the
2586 FIELD_DECL node just created and link that with the
2587 corresponding GNAT defining identifier. Then add to the
2588 list of fields. */
2597 {
2600 }
2601 }
2603 /* Put the discriminants into the record (backwards), so we can
2604 know the appropriate discriminant to use for the names of the
2605 variants. */
2608 /* Add the listed fields into the record and finish it up. */
2614 /* We used to remove the associations of the discriminants and
2615 _Parent for validity checking, but we may need them if there's
2616 Freeze_Node for a subtype used in this record. */
2620 /* If it is a tagged record force the type to BLKmode to insure
2621 that these objects will always be placed in memory. Do the
2622 same thing for limited record types. */
2626 /* If this is a derived type, we must make the alias set of this type
2627 the same as that of the type we are derived from. We assume here
2628 that the other type is already frozen. */
2634 /* Fill in locations of fields. */
2637 /* If there are any entities in the chain corresponding to
2638 components that we did not elaborate, ensure we elaborate their
2639 types if they are Itypes. */
2647 }
2651 /* If an equivalent type is present, that is what we should use.
2652 Otherwise, fall through to handle this like a record subtype
2653 since it may have constraints. */
2655 {
2659 }
2661 /* ... fall through ... */
2665 /* If Cloned_Subtype is Present it means this record subtype has
2666 identical layout to that type or subtype and we should use
2667 that GCC type for this one. The front end guarantees that
2668 the component list is shared. */
2670 {
2674 }
2676 /* Otherwise, first ensure the base type is elaborated. Then, if we are
2677 changing the type, make a new type with each field having the
2678 type of the field in the new subtype but having the position
2679 computed by transforming every discriminant reference according
2680 to the constraints. We don't see any difference between
2681 private and nonprivate type here since derivations from types should
2682 have been deferred until the completion of the private type. */
2683 else
2684 {
2686 tree gnu_base_type;
2687 tree gnu_orig_type;
2692 /* Get the base type initially for its alignment and sizes. But
2693 if it is a padded type, we do all the other work with the
2694 unpadded type. */
2700 else
2704 {
2707 }
2709 /* When the type has discriminants, and these discriminants
2710 affect the shape of what it built, factor them in.
2712 If we are making a subtype of an Unchecked_Union (must be an
2713 Itype), just return the type.
2715 We can't just use Is_Constrained because private subtypes without
2716 discriminants of full types with discriminants with default
2717 expressions are Is_Constrained but aren't constrained! */
2725 {
2726 Entity_Id gnat_field;
2728 tree gnu_pos_list
2731 BIGGEST_ALIGNMENT);
2732 tree gnu_subst_list
2734 definition);
2735 tree gnu_temp;
2751 {
2752 tree gnu_old_field
2755 tree gnu_offset
2757 gnu_pos_list));
2760 tree gnu_field_type
2764 unsigned int offset_align
2767 tree gnu_field;
2769 /* If there was a component clause, the field types must be
2770 the same for the type and subtype, so copy the data from
2771 the old field to avoid recomputation here. Also if the
2772 field is justified modular and the optimization in
2773 gnat_to_gnu_field was applied. */
2780 {
2783 }
2785 /* If the old field was packed and of constant size, we
2786 have to get the old size here, as it might differ from
2787 what the Etype conveys and the latter might overlap
2788 onto the following field. Try to arrange the type for
2789 possible better packing along the way. */
2793 {
2799 }
2808 /* If the size is now a constant, we can set it as the
2809 size of the field when we make it. Otherwise, we need
2810 to deal with it specially. */
2814 gnu_field
2815 = create_field_decl
2821 {
2830 bitsize_unit_node));
2832 }
2836 SET_DECL_ORIGINAL_FIELD
2847 }
2849 /* Now go through the entities again looking for Itypes that
2850 we have not elaborated but should (e.g., Etypes of fields
2851 that have Original_Components). */
2859 /* Do not finalize it since we're going to modify it below. */
2863 /* Now set the size, alignment and alias set of the new type to
2864 match that of the old one, doing any substitutions, as
2865 above. */
2891 SET_TYPE_ADA_SIZE
2896 /* Reapply variable_size since we have changed the sizes. */
2901 /* Recompute the mode of this record type now that we know its
2902 actual size. */
2905 /* Fill in locations of fields. */
2908 /* We've built a new type, make an XVS type to show what this
2909 is a subtype of. Some debuggers require the XVS type to be
2910 output first, so do it in that order. */
2912 {
2923 integer_type_node,
2924 gnu_subtype_marker,
2928 }
2930 /* Now we can finalize it. */
2932 }
2934 /* Otherwise, go down all the components in the new type and
2935 make them equivalent to those in the base type. */
2936 else
2943 gnat_to_gnu_field_decl
2945 }
2950 /* If we are not defining this entity, and we have incomplete
2951 entities being processed above us, make a dummy type and
2952 fill it in later. */
2954 {
2958 gnu_type
2959 = build_pointer_type
2974 }
2976 /* ... fall through ... */
2983 {
2986 bool is_from_limited_with
2990 /* Get the "full view" of this entity. If this is an incomplete
2991 entity from a limited with, treat its non-limited view as the full
2992 view. Otherwise, if this is an incomplete or private type, use the
2993 full view. In the former case, we might point to a private type,
2994 in which case, we need its full view. Also, we want to look at the
2995 actual type used for the representation, so this takes a total of
2996 three steps. */
2997 Entity_Id gnat_desig_full_direct_first
3001 Entity_Id gnat_desig_full_direct
3002 = ((is_from_limited_with
3007 Entity_Id gnat_desig_full
3010 /* This the type actually used to represent the designated type,
3011 either gnat_desig_full or gnat_desig_equiv. */
3012 Entity_Id gnat_desig_rep;
3014 /* Nonzero if this is a pointer to an unconstrained array. */
3017 /* We want to know if we'll be seeing the freeze node for any
3018 incomplete type we may be pointing to. */
3019 bool in_main_unit
3024 /* Nonzero if we make a dummy type here. */
3026 /* Nonzero if the dummy is a fat pointer. */
3034 /* If either the designated type or its full view is an unconstrained
3035 array subtype, replace it with the type it's a subtype of. This
3036 avoids problems with multiple copies of unconstrained array types.
3037 Likewise, if the designated type is a subtype of an incomplete
3038 record type, use the parent type to avoid order of elaboration
3039 issues. This can lose some code efficiency, but there is no
3040 alternative. */
3051 /* Now set the type that actually marks the representation of
3052 the designated type and also flag whether we have a unconstrained
3053 array. */
3055 is_unconstrained_array
3059 /* If we are pointing to an incomplete type whose completion is an
3060 unconstrained array, make a fat pointer type. The two types in our
3061 fields will be pointers to dummy nodes and will be replaced in
3062 update_pointer_to. Similarly, if the type itself is a dummy type or
3063 an unconstrained array. Also make a dummy TYPE_OBJECT_RECORD_TYPE
3064 in case we have any thin pointers to it. */
3075 {
3076 tree gnu_old
3080 tree fields;
3082 /* Show the dummy we get will be a fat pointer. */
3085 /* If the call above got something that has a pointer, that
3086 pointer is our type. This could have happened either
3087 because the type was elaborated or because somebody
3088 else executed the code below. */
3091 {
3112 fields
3114 create_field_decl
3116 gnu_ptr_array,
3119 gnu_ptr_template,
3122 /* Make sure we can place this into a register. */
3127 /* Do not finalize this record type since the types of
3128 its fields are incomplete. */
3136 }
3137 }
3139 /* If we already know what the full type is, use it. */
3144 /* Get the type of the thing we are to point to and build a pointer
3145 to it. If it is a reference to an incomplete or private type with a
3146 full view that is a record, make a dummy type node and get the
3147 actual type later when we have verified it is safe. */
3153 /* Likewise if we are pointing to a record or array and we
3154 are to defer elaborating incomplete types. We do this
3155 since this access type may be the full view of some
3156 private type. Note that the unconstrained array case is
3157 handled above. */
3163 /* If this is a reference from a limited_with type back to our
3164 main unit and there's a Freeze_Node for it, either we have
3165 already processed the declaration and made the dummy type,
3166 in which case we just reuse the latter, or we have not yet,
3167 in which case we make the dummy type and it will be reused
3168 when the declaration is processed. In both cases, the
3169 pointer eventually created below will be automatically
3170 adjusted when the Freeze_Node is processed. Note that the
3171 unconstrained array case is handled above. */
3174 {
3177 }
3179 /* Otherwise handle the case of a pointer to itself. */
3181 {
3182 gnu_type
3186 }
3188 /* If expansion is disabled, the equivalent type of a concurrent
3189 type is absent, so build a dummy pointer type. */
3193 /* Finally, handle the straightforward case where we can just
3194 elaborate our designated type and point to it. */
3195 else
3198 /* It is possible that a call to gnat_to_gnu_type above resolved our
3199 type. If so, just return it. */
3201 {
3204 }
3206 /* If we have a GCC type for the designated type, possibly modify it
3207 if we are pointing only to constant objects and then make a pointer
3208 to it. Don't do this for unconstrained arrays. */
3210 {
3213 {
3214 gnu_desig_type
3215 = build_qualified_type
3219 /* Some extra processing is required if we are building a
3220 pointer to an incomplete type (in the GCC sense). We might
3221 have such a type if we just made a dummy, or directly out
3222 of the call to gnat_to_gnu_type above if we are processing
3223 an access type for a record component designating the
3224 record type itself. */
3226 {
3227 /* We must ensure that the pointer to variant we make will
3228 be processed by update_pointer_to when the initial type
3229 is completed. Pretend we made a dummy and let further
3230 processing act as usual. */
3233 /* We must ensure that update_pointer_to will not retrieve
3234 the dummy variant when building a properly qualified
3235 version of the complete type. We take advantage of the
3236 fact that get_qualified_type is requiring TYPE_NAMEs to
3237 match to influence build_qualified_type and then also
3238 update_pointer_to here. */
3241 }
3242 }
3244 gnu_type
3247 }
3249 /* If we are not defining this object and we made a dummy pointer,
3250 save our current definition, evaluate the actual type, and replace
3251 the tentative type we made with the actual one. If we are to defer
3252 actually looking up the actual type, make an entry in the
3253 deferred list. If this is from a limited with, we have to defer
3254 to the end of the current spec in two cases: first if the
3255 designated type is in the current unit and second if the access
3256 type is. */
3258 {
3259 tree gnu_old_type
3265 gnu_type
3266 = build_pointer_type
3267 (TYPE_OBJECT_RECORD_TYPE
3279 && ! (is_from_limited_with
3280 && (in_main_unit
3285 /* Note that the call to gnat_to_gnu_type here might have
3286 updated gnu_old_type directly, in which case it is not a
3287 dummy type any more when we get into update_pointer_to.
3289 This may happen for instance when the designated type is a
3290 record type, because their elaboration starts with an
3291 initial node from make_dummy_type, which may yield the same
3292 node as the one we got.
3294 Besides, variants of this non-dummy type might have been
3295 created along the way. update_pointer_to is expected to
3296 properly take care of those situations. */
3297 else
3298 {
3303 = (is_from_limited_with
3304 && (in_main_unit
3312 }
3313 }
3314 }
3321 else
3322 {
3323 /* The runtime representation is the equivalent type. */
3326 }
3339 /* We treat this as identical to its base type; any constraint is
3340 meaningful only to the front end.
3342 The designated type must be elaborated as well, if it does
3343 not have its own freeze node. Designated (sub)types created
3344 for constrained components of records with discriminants are
3345 not frozen by the front end and thus not elaborated by gigi,
3346 because their use may appear before the base type is frozen,
3347 and because it is not clear that they are needed anywhere in
3348 Gigi. With the current model, there is no correct place where
3349 they could be elaborated. */
3356 {
3357 /* If we are not defining this entity, and we have incomplete
3358 entities being processed above us, make a dummy type and
3359 elaborate it later. */
3361 {
3364 tree gnu_ptr_type
3365 = build_pointer_type
3372 }
3375 Incomplete_Or_Private_Kind))
3378 }
3383 /* Subprogram Entities
3385 The following access functions are defined for subprograms (functions
3386 or procedures):
3388 First_Formal The first formal parameter.
3389 Is_Imported Indicates that the subprogram has appeared in
3390 an INTERFACE or IMPORT pragma. For now we
3391 assume that the external language is C.
3392 Is_Exported Likewise but for an EXPORT pragma.
3393 Is_Inlined True if the subprogram is to be inlined.
3395 In addition for function subprograms we have:
3397 Etype Return type of the function.
3399 Each parameter is first checked by calling must_pass_by_ref on its
3400 type to determine if it is passed by reference. For parameters which
3401 are copied in, if they are Ada In Out or Out parameters, their return
3402 value becomes part of a record which becomes the return type of the
3403 function (C function - note that this applies only to Ada procedures
3404 so there is no Ada return type). Additional code to store back the
3405 parameters will be generated on the caller side. This transformation
3406 is done here, not in the front-end.
3408 The intended result of the transformation can be seen from the
3409 equivalent source rewritings that follow:
3411 struct temp {int a,b};
3412 procedure P (A,B: In Out ...) is temp P (int A,B)
3413 begin {
3414 .. ..
3415 end P; return {A,B};
3416 }
3418 temp t;
3419 P(X,Y); t = P(X,Y);
3420 X = t.a , Y = t.b;
3422 For subprogram types we need to perform mainly the same conversions to
3423 GCC form that are needed for procedures and function declarations. The
3424 only difference is that at the end, we make a type declaration instead
3425 of a function declaration. */
3430 {
3431 /* The first GCC parameter declaration (a PARM_DECL node). The
3432 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3433 actually is the head of this parameter list. */
3435 /* Likewise for the stub associated with an exported procedure. */
3437 /* The type returned by a function. If the subprogram is a procedure
3438 this type should be void_type_node. */
3440 /* List of fields in return type of procedure with copy-in copy-out
3441 parameters. */
3443 /* Non-null for subprograms containing parameters passed by copy-in
3444 copy-out (Ada In Out or Out parameters not passed by reference),
3445 in which case it is the list of nodes used to specify the values of
3446 the in out/out parameters that are returned as a record upon
3447 procedure return. The TREE_PURPOSE of an element of this list is
3448 a field of the record and the TREE_VALUE is the PARM_DECL
3449 corresponding to that field. This list will be saved in the
3450 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3452 /* If an import pragma asks to map this subprogram to a GCC builtin,
3453 this is the builtin DECL node. */
3455 /* For the stub associated with an exported procedure. */
3458 Entity_Id gnat_param;
3461 bool extern_flag
3473 /* A parameter may refer to this type, so defer completion
3474 of any incomplete types. */
3477 /* If the subprogram has an alias, it is probably inherited, so
3478 we can use the original one. If the original "subprogram"
3479 is actually an enumeration literal, it may be the first use
3480 of its type, so we must elaborate that type now. */
3482 {
3489 /* Elaborate any Itypes in the parameters of this entity. */
3497 }
3499 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3500 corresponding DECL node.
3502 We still want the parameter associations to take place because the
3503 proper generation of calls depends on it (a GNAT parameter without
3504 a corresponding GCC tree has a very specific meaning), so we don't
3505 just break here. */
3509 /* ??? What if we don't find the builtin node above ? warn ? err ?
3510 In the current state we neither warn nor err, and calls will just
3511 be handled as for regular subprograms. */
3516 /* If this function returns by reference, make the actual
3517 return type of this function the pointer and mark the decl. */
3519 {
3522 }
3524 /* If the Mechanism is By_Reference, ensure the return type uses
3525 the machine's by-reference mechanism, which may not the same
3526 as above (e.g., it might be by passing a fake parameter). */
3529 {
3532 /* We expect this bit to be reset by gigi shortly, so can avoid a
3533 type node copy here. This actually also prevents troubles with
3534 the generation of debug information for the function, because
3535 we might have issued such info for this type already, and would
3536 be attaching a distinct type node to the function if we made a
3537 copy here. */
3538 }
3540 /* If we are supposed to return an unconstrained array,
3541 actually return a fat pointer and make a note of that. Return
3542 a pointer to an unconstrained record of variable size. */
3544 {
3547 }
3549 /* If the type requires a transient scope, the result is allocated
3550 on the secondary stack, so the result type of the function is
3551 just a pointer. */
3553 {
3556 }
3558 /* If the type is a padded type and the underlying type would not
3559 be passed by reference or this function has a foreign convention,
3560 return the underlying type. */
3568 /* If the return type is unconstrained, that means it must have a
3569 maximum size. We convert the function into a procedure and its
3570 caller will pass a pointer to an object of that maximum size as the
3571 first parameter when we call the function. */
3573 {
3575 gnu_param_list
3580 }
3582 /* If the return type has a size that overflows, we cannot have
3583 a function that returns that type. This usage doesn't make
3584 sense anyway, so give an error here. */
3588 {
3590 gnat_entity);
3596 }
3598 /* Look at all our parameters and get the type of
3599 each. While doing this, build a copy-out structure if
3600 we need one. */
3602 /* Loop over the parameters and get their associated GCC tree.
3603 While doing this, build a copy-out structure if we need one. */
3607 {
3614 /* Builtins are expanded inline and there is no real call sequence
3615 involved. So the type expected by the underlying expander is
3616 always the type of each argument "as is". */
3619 /* Handle the first parameter of a valued procedure specially. */
3622 /* Otherwise, see if a Mechanism was supplied that forced this
3623 parameter to be passed one way or another. */
3626 ;
3630 {
3634 mech))
3636 else
3638 }
3639 else
3640 {
3643 }
3645 gnu_param
3650 /* We are returned either a PARM_DECL or a type if no parameter
3651 needs to be passed; in either case, adjust the type. */
3654 else
3655 {
3658 }
3661 {
3662 /* If it's an exported subprogram, we build a parameter list
3663 in parallel, in case we need to emit a stub for it. */
3665 {
3666 gnu_stub_param_list
3668 /* Change By_Descriptor parameter to By_Reference for
3669 the internal version of an exported subprogram. */
3671 {
3672 gnu_param
3677 }
3678 else
3680 }
3687 /* If a parameter is a pointer, this function may modify
3688 memory through it and thus shouldn't be considered
3689 a pure function. Also, the memory may be modified
3690 between two calls, so they can't be CSE'ed. The latter
3691 case also handles by-ref parameters. */
3695 }
3698 {
3700 {
3705 }
3714 gnu_return_list);
3715 }
3716 }
3718 /* Do not compute record for out parameters if subprogram is
3719 stubbed since structures are incomplete for the back-end. */
3724 /* If we have a CICO list but it has only one entry, we convert
3725 this function into a function that simply returns that one
3726 object. */
3731 prepend_one_attribute_to
3734 gnat_entity);
3736 /* The lists have been built in reverse. */
3746 gnu_type
3749 returns_by_ref,
3751 returns_by_target_ptr);
3754 gnu_stub_type
3757 returns_by_ref,
3759 returns_by_target_ptr);
3761 /* A subprogram (something that doesn't return anything) shouldn't
3762 be considered Pure since there would be no reason for such a
3763 subprogram. Note that procedures with Out (or In Out) parameters
3764 have already been converted into a function with a return type. */
3768 /* The semantics of "pure" in Ada essentially matches that of "const"
3769 in the back-end. In particular, both properties are orthogonal to
3770 the "nothrow" property. But this is true only if the EH circuitry
3771 is explicit in the internal representation of the back-end. If we
3772 are to completely hide the EH circuitry from it, we need to declare
3773 that calls to pure Ada subprograms that can throw have side effects
3774 since they can trigger an "abnormal" transfer of control flow; thus
3775 they can be neither "const" nor "pure" in the back-end sense. */
3776 gnu_type
3786 gnu_stub_type
3793 /* If we have a builtin decl for that function, check the signatures
3794 compatibilities. If the signatures are compatible, use the builtin
3795 decl. If they are not, we expect the checker predicate to have
3796 posted the appropriate errors, and just continue with what we have
3797 so far. */
3799 {
3803 {
3807 }
3808 }
3810 /* If there was no specified Interface_Name and the external and
3811 internal names of the subprogram are the same, only use the
3812 internal name to allow disambiguation of nested subprograms. */
3816 /* If we are defining the subprogram and it has an Address clause
3817 we must get the address expression from the saved GCC tree for the
3818 subprogram if it has a Freeze_Node. Otherwise, we elaborate
3819 the address expression here since the front-end has guaranteed
3820 in that case that the elaboration has no effects. If there is
3821 an Address clause and we are not defining the object, just
3822 make it a constant. */
3824 {
3828 gnu_address
3835 /* Convert the type of the object to a reference type that can
3836 alias everything as per 13.3(19). */
3837 gnu_type
3842 gnu_decl
3847 }
3853 else
3854 {
3856 {
3860 }
3866 gnat_entity);
3868 {
3869 tree gnu_stub_decl
3874 gnat_entity);
3876 }
3878 /* This is unrelated to the stub built right above. */
3881 }
3882 }
3893 {
3894 /* Get the "full view" of this entity. If this is an incomplete
3895 entity from a limited with, treat its non-limited view as the
3896 full view. Otherwise, use either the full view or the underlying
3897 full view, whichever is present. This is used in all the tests
3898 below. */
3899 Entity_Id full_view
3907 /* If this is an incomplete type with no full view, it must be a Taft
3908 Amendment type, in which case we return a dummy type. Otherwise,
3909 just get the type from its Etype. */
3911 {
3914 else
3915 {
3919 }
3921 }
3923 /* If we already made a type for the full view, reuse it. */
3925 {
3928 }
3930 /* Otherwise, if we are not defining the type now, get the type
3931 from the full view. But always get the type from the full view
3932 for define on use types, since otherwise we won't see them! */
3938 {
3942 }
3944 /* For incomplete types, make a dummy type entry which will be
3945 replaced later. */
3948 /* Save this type as the full declaration's type so we can do any
3949 needed updates when we see it. */
3955 }
3957 /* Simple class_wide types are always viewed as their root_type
3958 by Gigi unless an Equivalent_Type is specified. */
3970 else
3982 /* Nothing at all to do here, so just return an ERROR_MARK and claim
3983 we've already saved it, so we don't try to. */
3990 }
3992 /* If we had a case where we evaluated another type and it might have
3993 defined this one, handle it here. */
3995 {
3998 }
4000 /* If we are processing a type and there is either no decl for it or
4001 we just made one, do some common processing for the type, such as
4002 handling alignment and possible padding. */
4005 {
4013 /* ??? Don't set the size for a String_Literal since it is either
4014 confirming or we don't handle it properly (if the low bound is
4015 non-constant). */
4021 /* If a size was specified, see if we can make a new type of that size
4022 by rearranging the type, for example from a fat to a thin pointer. */
4024 {
4025 gnu_type
4032 }
4034 /* If the alignment hasn't already been processed and this is
4035 not an unconstrained array, see if an alignment is specified.
4036 If not, we pick a default alignment for atomic objects. */
4038 ;
4052 /* See if we need to pad the type. If we did, and made a record,
4053 the name of the new type may be changed. So get it back for
4054 us when we make the new TYPE_DECL below. */
4059 {
4063 }
4067 /* If we are at global level, GCC will have applied variable_size to
4068 the type, but that won't have done anything. So, if it's not
4069 a constant or self-referential, call elaborate_expression_1 to
4070 make a variable for the size rather than calculating it each time.
4071 Handle both the RM size and the actual size. */
4076 {
4080 {
4087 }
4088 else
4089 {
4096 /* ??? For now, store the size as a multiple of the alignment
4097 in bytes so that we can see the alignment from the tree. */
4099 = build_binary_op
4101 elaborate_expression_1
4112 SET_TYPE_ADA_SIZE
4115 gnat_entity,
4119 }
4120 }
4122 /* If this is a record type or subtype, call elaborate_expression_1 on
4123 any field position. Do this for both global and local types.
4124 Skip any fields that we haven't made trees for to avoid problems with
4125 class wide types. */
4130 {
4133 /* ??? Unfortunately, GCC needs to be able to prove the
4134 alignment of this offset and if it's a variable, it can't.
4135 In GCC 3.4, we'll use DECL_OFFSET_ALIGN in some way, but
4136 right now, we have to put in an explicit multiply and
4137 divide by that value. */
4139 {
4141 = build_binary_op
4143 elaborate_expression_1
4153 /* ??? The context of gnu_field is not necessarily gnu_type so
4154 the MULT_EXPR node built above may not be marked by the call
4155 to create_type_decl below. Mark it manually for now. */
4158 }
4159 }
4163 | (TYPE_QUAL_VOLATILE
4179 else
4181 }
4184 {
4187 /* Back-annotate the Alignment of the type if not already in the
4188 tree. Likewise for sizes. */
4194 {
4195 /* If the size is self-referential, we annotate the maximum
4196 value of that size. */
4205 {
4206 /* In this mode the tag and the parent components are not
4207 generated by the front-end, so the sizes must be adjusted
4208 explicitly now. */
4212 {
4213 size_offset
4217 }
4218 else
4226 }
4227 }
4231 }
4241 /* If we haven't already, associate the ..._DECL node that we just made with
4242 the input GNAT entity node. */
4246 /* If this is an enumeral or floating-point type, we were not able to set
4247 the bounds since they refer to the type. These bounds are always static.
4249 For enumeration types, also write debugging information and declare the
4250 enumeration literal table, if needed. */
4254 {
4257 /* If this is a padded type, we need to use the underlying type. */
4262 /* If this is a floating point type and we haven't set a floating
4263 point type yet, use this in the evaluation of the bounds. */
4273 {
4276 /* Since this has both a typedef and a tag, avoid outputting
4277 the name twice. */
4280 }
4281 }
4283 /* If we deferred processing of incomplete types, re-enable it. If there
4284 were no other disables and we have some to process, do so. */
4286 {
4288 {
4291 /* We are back to level 0 for the deferring of incomplete types.
4292 But processing these incomplete types below may itself require
4293 deferring, so preserve what we have and restart from scratch. */
4297 /* For finalization, however, all types must be complete so we
4298 cannot do the same because deferred incomplete types may end up
4299 referencing each other. Process them all recursively first. */
4300 defer_finalize_level++;
4303 {
4310 }
4312 defer_finalize_level--;
4313 }
4315 /* All the deferred incomplete types have been processed so we can
4316 now proceed with the finalization of the deferred types. */
4318 {
4321 tree t;
4327 }
4328 }
4330 /* If we are not defining this type, see if it's in the incomplete list.
4331 If so, handle that list entry now. */
4333 {
4338 {
4342 }
4343 }
4346 force_global--;
4355 }
4357 /* Similar, but if the returned value is a COMPONENT_REF, return the
4358 FIELD_DECL. */
4360 tree
4362 {
4369 }
4371 /* Wrap up compilation of T, a TYPE_DECL, possibly deferring it. */
4373 void
4375 {
4376 /* We need to defer finalizing the type if incomplete types
4377 are being deferred or if they are being processed. */
4380 else
4382 }
4384 /* Finalize any From_With_Type incomplete types. We do this after processing
4385 our compilation unit and after processing its spec, if this is a body. */
4387 void
4389 {
4395 {
4402 }
4403 }
4405 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
4406 kind of type (such E_Task_Type) that has a different type which Gigi
4407 uses for its representation. If the type does not have a special type
4408 for its representation, return GNAT_ENTITY. If a type is supposed to
4409 exist, but does not, abort unless annotating types, in which case
4410 return Empty. If GNAT_ENTITY is Empty, return Empty. */
4412 Entity_Id
4414 {
4421 {
4447 }
4451 }
4453 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
4454 using MECH as its passing mechanism, to be placed in the parameter
4455 list built for GNAT_SUBPROG. Assume a foreign convention for the
4456 latter if FOREIGN is true. Also set CICO to true if the parameter
4457 must use the copy-in copy-out implementation mechanism.
4459 The returned tree is a PARM_DECL, except for those cases where no
4460 parameter needs to be actually passed to the subprogram; the type
4461 of this "shadow" parameter is then returned instead. */
4463 static tree
4466 {
4470 /* The parameter can be indirectly modified if its address is taken. */
4473 tree gnu_param;
4475 /* Copy-return is used only for the first parameter of a valued procedure.
4476 It's a copy mechanism for which a parameter is never allocated. */
4478 {
4482 }
4484 /* If this is either a foreign function or if the underlying type won't
4485 be passed by reference, strip off possible padding type. */
4488 {
4492 || foreign
4496 }
4498 /* If this is a read-only parameter, make a variant of the type that is
4499 read-only. ??? However, if this is an unconstrained array, that type
4500 can be very complex, so skip it for now. Likewise for any other
4501 self-referential type. */
4509 /* For foreign conventions, pass arrays as pointers to the element type.
4510 First check for unconstrained array and get the underlying array. */
4512 gnu_param_type
4515 /* VMS descriptors are themselves passed by reference. */
4517 gnu_param_type
4520 gnat_subprog));
4522 /* Arrays are passed as pointers to element type for foreign conventions. */
4526 {
4527 /* Strip off any multi-dimensional entries, then strip
4528 off the last array to get the component type. */
4542 }
4544 /* Fat pointers are passed as thin pointers for foreign conventions. */
4546 gnu_param_type
4549 /* If we must pass or were requested to pass by reference, do so.
4550 If we were requested to pass by copy, do so.
4551 Otherwise, for foreign conventions, pass In Out or Out parameters
4552 or aggregates by reference. For COBOL and Fortran, pass all
4553 integer and FP types that way too. For Convention Ada, use
4554 the standard Ada default. */
4558 && ((foreign
4560 || (foreign
4565 || (!foreign
4567 {
4570 }
4572 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
4579 /* If this is an Out parameter that isn't passed by reference and isn't
4580 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
4581 it will be a VAR_DECL created when we process the procedure, so just
4582 return its type. For the special parameter of a valued procedure,
4583 never pass it in.
4585 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
4586 Out parameters with discriminants or implicit initial values to be
4587 handled like In Out parameters. These type are normally built as
4588 aggregates, hence passed by reference, except for some packed arrays
4589 which end up encoded in special integer types.
4591 The exception we need to make is then for packed arrays of records
4592 with discriminants or implicit initial values. We have no light/easy
4593 way to check for the latter case, so we merely check for packed arrays
4594 of records. This may lead to useless copy-in operations, but in very
4595 rare cases only, as these would be exceptions in a set of already
4596 exceptional situations. */
4598 && !by_ref
4599 && (by_return
4616 /* If no Mechanism was specified, indicate what we're using, then
4617 back-annotate it. */
4623 }
4625 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
4627 static bool
4629 {
4636 return
4638 }
4640 /* Return true if the array type specified by GNAT_TYPE and GNU_TYPE has
4641 a non-aliased component in the back-end sense. */
4643 static bool
4645 {
4646 /* If the type below this is a multi-array type, then
4647 this does not have aliased components. */
4656 }
4657 \f
4658 /* Given GNAT_ENTITY, elaborate all expressions that are required to
4659 be elaborated at the point of its definition, but do nothing else. */
4661 void
4663 {
4665 {
4672 {
4676 /* ??? Tests for avoiding static constraint error expression
4677 is needed until the front stops generating bogus conversions
4678 on bounds of real types. */
4687 }
4690 {
4694 /* If this is a record extension, go a level further to find the
4695 record definition. */
4698 }
4708 {
4709 Node_Id gnat_discriminant_expr;
4710 Entity_Id gnat_field;
4713 gnat_discriminant_expr
4718 /* ??? For now, ignore access discriminants. */
4721 gnat_entity,
4723 }
4726 }
4727 }
4728 \f
4729 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
4730 any entities on its entity chain similarly. */
4732 void
4734 {
4735 Entity_Id gnat_sub_entity;
4738 /* If this has an entity list, process all in the list. */
4755 /* Now clear this if it has been defined, but only do so if it isn't
4756 a subprogram or parameter. We could refine this, but it isn't
4757 worth it. If this is statically allocated, it is supposed to
4758 hang around out of cope. */
4761 {
4764 }
4765 }
4766 \f
4767 /* Set the alias set of GNU_NEW_TYPE to be that of GNU_OLD_TYPE. If this
4768 is a multi-dimensional array type, do this recursively. */
4770 static void
4772 {
4773 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
4774 of a one-dimensional array, since the padding has the same alias set
4775 as the field type, but if it's a multi-dimensional array, we need to
4776 see the inner types. */
4782 /* We need to be careful here in case GNU_OLD_TYPE is an unconstrained
4783 array. In that case, it doesn't have the same shape as GNU_NEW_TYPE,
4784 so we need to go down to what does. */
4786 gnu_old_type
4796 }
4797 \f
4798 /* Return a TREE_LIST describing the substitutions needed to reflect
4799 discriminant substitutions from GNAT_SUBTYPE to GNAT_TYPE and add
4800 them to GNU_LIST. If GNAT_TYPE is not specified, use the base type
4801 of GNAT_SUBTYPE. The substitutions can be in any order. TREE_PURPOSE
4802 gives the tree for the discriminant and TREE_VALUES is the replacement
4803 value. They are in the form of operands to substitute_in_expr.
4804 DEFINITION is as in gnat_to_gnu_entity. */
4806 static tree
4809 {
4810 Entity_Id gnat_discrim;
4811 Node_Id gnat_value;
4822 /* Ignore access discriminants. */
4825 elaborate_expression
4829 gnu_list);
4832 }
4833 \f
4834 /* Return true if the size represented by GNU_SIZE can be handled by an
4835 allocation. If STATIC_P is true, consider only what can be done with a
4836 static allocation. */
4838 static bool
4840 {
4841 HOST_WIDE_INT our_size;
4843 /* If this is not a static allocation, the only case we want to forbid
4844 is an overflowing size. That will be converted into a raise a
4845 Storage_Error. */
4850 /* Otherwise, we need to deal with both variable sizes and constant
4851 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
4852 since assemblers may not like very large sizes. */
4858 }
4859 \f
4860 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
4861 NAME, ARGS and ERROR_POINT. */
4863 static void
4866 tree attr_name,
4867 tree attr_args,
4868 Node_Id attr_error_point)
4869 {
4879 }
4881 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
4883 static void
4885 {
4886 Node_Id gnat_temp;
4891 {
4900 {
4902 (gnat_to_gnu
4909 (gnat_to_gnu
4910 (Expression
4913 }
4916 {
4943 }
4946 /* Prepend to the list now. Make a list of the argument we might
4947 have, as GCC expects it. */
4948 prepend_one_attribute_to
4955 }
4956 }
4957 \f
4958 /* Get the unpadded version of a GNAT type. */
4960 tree
4962 {
4969 }
4970 \f
4971 /* Called when we need to protect a variable object using a save_expr. */
4973 tree
4975 {
4982 {
4990 }
4991 else
4993 }
4994 \f
4995 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
4996 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
4997 return the GCC tree to use for that expression. GNU_NAME is the
4998 qualification to use if an external name is appropriate and DEFINITION is
4999 nonzero if this is a definition of GNAT_ENTITY. If NEED_VALUE is nonzero,
5000 we need a result. Otherwise, we are just elaborating this for
5001 side-effects. If NEED_DEBUG is nonzero we need the symbol for debugging
5002 purposes even if it isn't needed for code generation. */
5004 static tree
5008 {
5009 tree gnu_expr;
5011 /* If we already elaborated this expression (e.g., it was involved
5012 in the definition of a private type), use the old value. */
5016 /* If we don't need a value and this is static or a discriminant, we
5017 don't need to do anything. */
5024 /* Otherwise, convert this tree to its GCC equivalent. */
5025 gnu_expr
5029 /* Save the expression in case we try to elaborate this entity again. Since
5030 this is not a DECL, don't check it. Don't save if it's a discriminant. */
5035 }
5037 /* Similar, but take a GNU expression. */
5039 static tree
5043 {
5045 /* Strip any conversions to see if the expression is a readonly variable.
5046 ??? This really should remain readonly, but we have to think about
5047 the typing of the tree here. */
5052 /* In most cases, we won't see a naked FIELD_DECL here because a
5053 discriminant reference will have been replaced with a COMPONENT_REF
5054 when the type is being elaborated. However, there are some cases
5055 involving child types where we will. So convert it to a COMPONENT_REF
5056 here. We have to hope it will be at the highest level of the
5057 expression in these cases. */
5063 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
5064 that is a constant, make a variable that is initialized to contain the
5065 bound when the package containing the definition is elaborated. If
5066 this entity is defined at top level and a bound or discriminant value
5067 isn't a constant or a reference to a discriminant, replace the bound
5068 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
5069 rely here on the fact that an expression cannot contain both the
5070 discriminant and some other variable. */
5078 /* If this is a static expression or contains a discriminant, we don't
5079 need the variable for debugging (and can't elaborate anyway if a
5080 discriminant). */
5086 /* Now create the variable if we need it. */
5088 gnu_decl
5095 /* We only need to use this variable if we are in global context since GCC
5096 can do the right thing in the local case. */
5101 else
5103 }
5104 \f
5105 /* Create a record type that contains a SIZE bytes long field of TYPE with a
5106 starting bit position so that it is aligned to ALIGN bits, and leaving at
5107 least ROOM bytes free before the field. BASE_ALIGN is the alignment the
5108 record is guaranteed to get. */
5110 tree
5113 {
5114 /* We will be crafting a record type with one field at a position set to be
5115 the next multiple of ALIGN past record'address + room bytes. We use a
5116 record placeholder to express record'address. */
5121 tree record_addr_st
5124 /* The diagram below summarizes the shape of what we manipulate:
5126 <--------- pos ---------->
5127 { +------------+-------------+-----------------+
5128 record =>{ |############| ... | field (type) |
5129 { +------------+-------------+-----------------+
5130 |<-- room -->|<- voffset ->|<---- size ----->|
5131 o o
5132 | |
5133 record_addr vblock_addr
5135 Every length is in sizetype bytes there, except "pos" which has to be
5136 set as a bit position in the GCC tree for the record. */
5149 /* Compute VOFFSET and then POS. The next byte position multiple of some
5150 alignment after some address is obtained by "and"ing the alignment minus
5151 1 with the two's complement of the address. */
5157 /* POS = (ROOM + VOFFSET) * BIT_PER_UNIT, in bitsizetype. */
5162 bitsize_unit_node);
5164 /* Craft the GCC record representation. We exceptionally do everything
5165 manually here because 1) our generic circuitry is not quite ready to
5166 handle the complex position/size expressions we are setting up, 2) we
5167 have a strong simplifying factor at hand: we know the maximum possible
5168 value of voffset, and 3) we have to set/reset at least the sizes in
5169 accordance with this maximum value anyway, as we need them to convey
5170 what should be "alloc"ated for this type.
5172 Use -1 as the 'addressable' indication for the field to prevent the
5173 creation of a bitfield. We don't need one, it would have damaging
5174 consequences on the alignment computation, and create_field_decl would
5175 make one without this special argument, for instance because of the
5176 complex position expression. */
5188 bitsize_unit_node),
5198 }
5199 \f
5200 /* TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE, with BLKmode that's
5201 being used as the field type of a packed record. See if we can rewrite it
5202 as a record that has a non-BLKmode type, which we can pack tighter. If so,
5203 return the new type. If not, return the original type. */
5205 static tree
5207 {
5210 tree old_field;
5212 /* Copy the name and flags from the old type to that of the new. Note
5213 that we rely on the pointer equality created here for TYPE_NAME at
5214 the end of gnat_to_gnu. For QUAL_UNION_TYPE, also copy the size. */
5222 {
5225 }
5227 /* Set the alignment to try for an integral type. */
5231 /* Now copy the fields, keeping the position and size. */
5234 {
5236 tree new_field;
5252 SET_DECL_ORIGINAL_FIELD
5261 }
5266 /* Try harder to get a packable type if necessary, for example
5267 in case the record itself contains a BLKmode field. */
5273 }
5274 \f
5275 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
5276 if needed. We have already verified that SIZE and TYPE are large enough.
5278 GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
5279 to issue a warning.
5281 IS_USER_TYPE is true if we must be sure we complete the original type.
5283 DEFINITION is true if this type is being defined.
5285 SAME_RM_SIZE is true if the RM_Size of the resulting type is to be
5286 set to its TYPE_SIZE; otherwise, it's set to the RM_Size of the original
5287 type. */
5289 tree
5293 {
5296 tree record;
5297 tree field;
5299 /* If TYPE is a padded type, see if it agrees with any size and alignment
5300 we were given. If so, return the original type. Otherwise, strip
5301 off the padding, since we will either be returning the inner type
5302 or repadding it. If no size or alignment is specified, use that of
5303 the original padded type. */
5306 {
5323 }
5325 /* If the size is either not being changed or is being made smaller (which
5326 is not done here (and is only valid for bitfields anyway), show the size
5327 isn't changing. Likewise, clear the alignment if it isn't being
5328 changed. Then return if we aren't doing anything. */
5342 /* We used to modify the record in place in some cases, but that could
5343 generate incorrect debugging information. So make a new record
5344 type and name. */
5350 /* If we were making a type, complete the original type and give it a
5351 name. */
5358 gnat_entity);
5360 /* If we are changing the alignment and the input type is a record with
5361 BLKmode and a small constant size, try to make a form that has an
5362 integral mode. That might allow this record to have an integral mode,
5363 which will be much more efficient. There is no point in doing this if a
5364 size is specified unless it is also smaller than the biggest alignment
5365 and it is incorrect to do this if the size of the original type is not a
5366 multiple of the alignment. */
5372 && (!size
5395 /* Do not finalize it until after the auxiliary record is built. */
5398 /* Keep the RM_Size of the padded record as that of the old record
5399 if requested. */
5402 /* Unless debugging information isn't being written for the input type,
5403 write a record that shows what we are a subtype of and also make a
5404 variable that indicates our size, if variable. */
5409 {
5431 }
5435 /* If the size was widened explicitly, maybe give a warning. Take the
5436 original size as the maximum size of the input if there was an
5437 unconstrained record involved and round it up to the specified alignment,
5438 if one was specified. */
5450 {
5463 /* Generate message only for entities that come from source, since
5464 if we have an entity created by expansion, the message will be
5465 generated for some other corresponding source entity. */
5468 gnat_entity,
5475 }
5478 }
5479 \f
5480 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
5481 the value passed against the list of choices. */
5483 tree
5485 {
5486 Node_Id choice;
5487 Node_Id gnat_temp;
5492 {
5494 {
5499 /* There's no good type to use here, so we might as well use
5500 integer_type_node. */
5501 this_test
5515 this_test
5525 /* This represents either a subtype range, an enumeration
5526 literal, or a constant Ekind says which. If an enumeration
5527 literal or constant, fall through to the next case. */
5530 {
5536 this_test
5543 }
5544 /* ... fall through ... */
5549 single);
5558 }
5562 }
5565 }
5566 \f
5567 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
5568 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
5570 static int
5572 {
5573 /* If the field contains an item of variable size, we cannot pack it
5574 because we cannot create temporaries of non-fixed size. */
5578 /* If the alignment of the record is specified and the field type
5579 is over-aligned, request Storage_Unit alignment for the field. */
5581 {
5584 else
5586 }
5589 }
5591 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
5592 placed in GNU_RECORD_TYPE.
5594 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
5595 record has Component_Alignment of Storage_Unit, -2 if the enclosing
5596 record has a specified alignment.
5598 DEFINITION is true if this field is for a record being defined. */
5600 static tree
5603 {
5607 bool needs_strict_alignment
5611 /* If this field requires strict alignment, we cannot pack it because
5612 it would very likely be under-aligned in the record. */
5615 else
5618 /* If a size is specified, use it. Otherwise, if the record type is packed,
5619 use the official RM size. See "Handling of Type'Size Values" in Einfo
5620 for further details. */
5627 else
5630 /* If we have a specified size that's smaller than that of the field type,
5631 or a position is specified, and the field type is also a record that's
5632 BLKmode and with a small constant size, see if we can get an integral
5633 mode form of the type when appropriate. If we can, show a size was
5634 specified for the field if there wasn't one already, so we know to make
5635 this a bitfield and avoid making things wider.
5637 Doing this is first useful if the record is packed because we can then
5638 place the field at a non-byte-aligned position and so achieve tighter
5639 packing.
5641 This is in addition *required* if the field shares a byte with another
5642 field and the front-end lets the back-end handle the references, because
5643 GCC does not handle BLKmode bitfields properly.
5645 We avoid the transformation if it is not required or potentially useful,
5646 as it might entail an increase of the field's alignment and have ripple
5647 effects on the outer record type. A typical case is a field known to be
5648 byte aligned and not to share a byte with another field.
5650 Besides, we don't even look the possibility of a transformation in cases
5651 known to be in error already, for instance when an invalid size results
5652 from a component clause. */
5659 || (gnu_size
5662 {
5663 /* See what the alternate type and size would be. */
5666 bool has_byte_aligned_clause
5671 /* Compute whether we should avoid the substitution. */
5672 bool reject
5673 /* There is no point substituting if there is no change... */
5675 /* ... nor when the field is known to be byte aligned and not to
5676 share a byte with another field. */
5677 || (has_byte_aligned_clause
5679 /* The size of an aliased field must be an exact multiple of the
5680 type's alignment, which the substitution might increase. Reject
5681 substitutions that would so invalidate a component clause when the
5682 specified position is byte aligned, as the change would have no
5683 real benefit from the packing standpoint anyway. */
5685 && has_byte_aligned_clause
5688 /* Substitute unless told otherwise. */
5690 {
5695 }
5696 }
5698 /* If we are packing the record and the field is BLKmode, round the
5699 size up to a byte boundary. */
5704 {
5709 /* Ensure the position does not overlap with the parent subtype,
5710 if there is one. */
5712 {
5713 tree gnu_parent
5719 {
5720 post_error_ne_tree
5724 }
5725 }
5727 /* If this field needs strict alignment, ensure the record is
5728 sufficiently aligned and that that position and size are
5729 consistent with the alignment. */
5731 {
5737 {
5739 post_error_ne_tree
5745 post_error_ne_tree
5751 post_error_ne_tree
5757 }
5762 {
5764 post_error_ne_num
5770 post_error_ne_num
5776 post_error_ne_num
5781 else
5785 }
5786 }
5790 }
5792 /* If the record has rep clauses and this is the tag field, make a rep
5793 clause for it as well. */
5796 {
5799 }
5801 else
5804 /* We need to make the size the maximum for the type if it is
5805 self-referential and an unconstrained type. In that case, we can't
5806 pack the field since we can't make a copy to align it. */
5808 && !gnu_size
5811 {
5814 }
5816 /* If a size is specified, adjust the field's type to it. */
5818 {
5819 /* If the field's type is justified modular, we would need to remove
5820 the wrapper to (better) meet the layout requirements. However we
5821 can do so only if the field is not aliased to preserve the unique
5822 layout and if the prescribed size is not greater than that of the
5823 packed array to preserve the justification. */
5831 gnu_field_type
5836 }
5838 /* Otherwise (or if there was an error), don't specify a position. */
5839 else
5845 /* Now create the decl for the field. */
5857 }
5858 \f
5859 /* Return true if TYPE is a type with variable size, a padding type with a
5860 field of variable size or is a record that has a field such a field. */
5862 static bool
5864 {
5865 tree field;
5867 /* We need not be concerned about this at all if we don't have
5868 strict alignment. */
5886 }
5887 \f
5888 /* qsort comparer for the bit positions of two record components. */
5890 static int
5892 {
5895 const int ret
5899 }
5901 /* Return a GCC tree for a record type given a GNAT Component_List and a chain
5902 of GCC trees for fields that are in the record and have already been
5903 processed. When called from gnat_to_gnu_entity during the processing of a
5904 record type definition, the GCC nodes for the discriminants will be on
5905 the chain. The other calls to this function are recursive calls from
5906 itself for the Component_List of a variant and the chain is empty.
5908 PACKED is 1 if this is for a packed record, -1 if this is for a record
5909 with Component_Alignment of Storage_Unit, -2 if this is for a record
5910 with a specified alignment.
5912 DEFINITION is true if we are defining this record.
5914 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
5915 with a rep clause is to be added. If it is nonzero, that is all that
5916 should be done with such fields.
5918 CANCEL_ALIGNMENT, if true, means the alignment should be zeroed before
5919 laying out the record. This means the alignment only serves to force fields
5920 to be bitfields, but not require the record to be that aligned. This is
5921 used for variants.
5923 ALL_REP, if true, means a rep clause was found for all the fields. This
5924 simplifies the logic since we know we're not in the mixed case.
5926 DO_NOT_FINALIZE, if true, means that the record type is expected to be
5927 modified afterwards so it will not be sent to the back-end for finalization.
5929 UNCHECKED_UNION, if true, means that we are building a type for a record
5930 with a Pragma Unchecked_Union.
5932 The processing of the component list fills in the chain with all of the
5933 fields of the record and then the record type is finished. */
5935 static void
5940 {
5941 Node_Id component_decl;
5942 Entity_Id gnat_field;
5943 Node_Id variant_part;
5949 /* For each variable within each component declaration create a GCC field
5950 and add it to the list, skipping any pragmas in the list. */
5955 {
5960 else
5961 {
5965 /* If this is the _Tag field, put it before any discriminants,
5966 instead of after them as is the case for all other fields.
5967 Ignore field of void type if only annotating. */
5970 else
5971 {
5974 }
5975 }
5978 }
5980 /* At the end of the component list there may be a variant part. */
5983 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
5984 mutually exclusive and should go in the same memory. To do this we need
5985 to treat each variant as a record whose elements are created from the
5986 component list for the variant. So here we create the records from the
5987 lists for the variants and put them all into the QUAL_UNION_TYPE.
5988 If this is an Unchecked_Union, we make a UNION_TYPE instead or
5989 use GNU_RECORD_TYPE if there are no fields so far. */
5991 {
5993 Node_Id variant;
5995 tree gnu_var_name
5999 tree gnu_union_type;
6000 tree gnu_union_name;
6001 tree gnu_union_field;
6010 /* Reuse an enclosing union if all fields are in the variant part
6011 and there is no representation clause on the record, to match
6012 the layout of C unions. There is an associated check below. */
6017 else
6018 {
6019 gnu_union_type
6024 }
6029 {
6031 tree gnu_inner_name;
6032 tree gnu_qual;
6040 /* Set the alignment of the inner type in case we need to make
6041 inner objects into bitfields, but then clear it out
6042 so the record actually gets only the alignment required. */
6046 /* Similarly, if the outer record has a size specified and all fields
6047 have record rep clauses, we can propagate the size into the
6048 variant part. */
6050 {
6054 }
6056 /* Create the record type for the variant. Note that we defer
6057 finalizing it until after we are sure to actually use it. */
6068 /* If this is an Unchecked_Union and we have exactly one field,
6069 use that field here. */
6073 else
6074 {
6075 /* Deal with packedness like in gnat_to_gnu_field. */
6076 int field_packed
6079 /* Finalize the record type now. We used to throw away
6080 empty records but we no longer do that because we need
6081 them to generate complete debug info for the variant;
6082 otherwise, the union type definition will be lacking
6083 the fields associated with these empty variants. */
6088 (all_rep_and_size
6091 (all_rep_and_size
6099 }
6103 }
6105 /* Only make the QUAL_UNION_TYPE if there are any non-empty variants. */
6107 {
6109 {
6113 }
6118 /* If GNU_UNION_TYPE is our record type, it means we must have an
6119 Unchecked_Union with no fields. Verify that and, if so, just
6120 return. */
6122 {
6124 && !gnu_field_list
6127 }
6129 gnu_union_field
6131 packed,
6138 }
6139 }
6141 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
6142 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do this
6143 in a separate pass since we want to handle the discriminants but can't
6144 play with them until we've used them in debugging data above.
6146 ??? Note: if we then reorder them, debugging information will be wrong,
6147 but there's nothing that can be done about this at the moment. */
6149 {
6151 {
6156 else
6162 }
6163 else
6164 {
6167 }
6168 }
6170 /* If we have any items in our rep'ed field list, it is not the case that all
6171 the fields in the record have rep clauses, and P_REP_LIST is nonzero,
6172 set it and ignore the items. */
6176 {
6177 /* Otherwise, sort the fields by bit position and put them into their
6178 own record if we have any fields without rep clauses. */
6179 tree gnu_rep_type
6191 /* Put the fields in the list in order of increasing position, which
6192 means we start from the end. */
6195 {
6199 }
6202 {
6208 }
6209 else
6210 {
6213 }
6214 }
6221 }
6222 \f
6223 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
6224 placed into an Esize, Component_Bit_Offset, or Component_Size value
6225 in the GNAT tree. */
6227 static Uint
6229 {
6231 TCode tcode;
6237 /* See if we've already saved the value for this node. */
6239 {
6250 }
6252 /* If we do not return inside this switch, TCODE will be set to the
6253 code to use for a Create_Node operand and LEN (set above) will be
6254 the number of recursive calls for us to make. */
6257 {
6262 /* This may have come from a conversion from some smaller type,
6263 so ensure this is in bitsizetype. */
6266 /* For negative values, use NEGATE_EXPR of the supplied value. */
6268 {
6269 /* The ridiculous code below is to handle the case of the largest
6270 negative integer. */
6273 tree temp;
6276 {
6277 negative_size
6280 bitsize_one_node));
6282 }
6289 }
6296 /* This peculiar test is to make sure that the size fits in an int
6297 on machines where HOST_WIDE_INT is not "int". */
6300 else
6304 /* The only case we handle here is a simple discriminant reference. */
6312 else
6318 /* Now just list the operations we handle. */
6350 }
6352 /* Now get each of the operands that's relevant for this code. If any
6353 cannot be expressed as a repinfo node, say we can't. */
6358 {
6362 }
6366 /* Save the result in the cache. */
6368 {
6372 }
6375 }
6377 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding
6378 GCC type, set Component_Bit_Offset and Esize to the position and size
6379 used by Gigi. */
6381 static void
6383 {
6384 tree gnu_list;
6385 tree gnu_entry;
6386 Entity_Id gnat_field;
6388 /* We operate by first making a list of all fields and their positions
6389 (we can get the sizes easily at any time) by a recursive call
6390 and then update all the sizes into the tree. */
6393 BIGGEST_ALIGNMENT);
6400 {
6404 gnu_list);
6407 {
6409 {
6410 /* In this mode the tag and parent components have not been
6411 generated, so we add the appropriate offset to each
6412 component. For a component appearing in the current
6413 extension, the offset is the size of the parent. */
6416 parent_offset
6418 bitsizetype);
6419 else
6421 }
6423 Set_Component_Bit_Offset
6425 annotate_value
6430 parent_offset)));
6434 }
6437 {
6438 /* If there is no gnu_entry, this is an inherited component whose
6439 position is the same as in the parent type. */
6440 Set_Component_Bit_Offset
6445 }
6446 }
6447 }
6449 /* Scan all fields in GNU_TYPE and build entries where TREE_PURPOSE is the
6450 FIELD_DECL and TREE_VALUE a TREE_LIST with TREE_PURPOSE being the byte
6451 position and TREE_VALUE being a TREE_LIST with TREE_PURPOSE the value to be
6452 placed into DECL_OFFSET_ALIGN and TREE_VALUE the bit position. GNU_POS is
6453 to be added to the position, GNU_BITPOS to the bit position, OFFSET_ALIGN is
6454 the present value of DECL_OFFSET_ALIGN and GNU_LIST is a list of the entries
6455 so far. */
6457 static tree
6460 {
6461 tree gnu_field;
6466 {
6471 unsigned int our_offset_align
6474 gnu_result
6479 NULL_TREE),
6480 gnu_result);
6483 gnu_result
6486 our_offset_align);
6487 }
6490 }
6491 \f
6492 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
6493 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
6494 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
6495 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
6496 for the size of a field. COMPONENT_P is true if we are being called
6497 to process the Component_Size of GNAT_OBJECT. This is used for error
6498 message handling and to indicate to use the object size of GNU_TYPE.
6499 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
6500 it means that a size of zero should be treated as an unspecified size. */
6502 static tree
6505 {
6506 Node_Id gnat_error_node;
6510 /* If a type needs strict alignment, a component of this type in
6511 a packed record cannot be packed and thus uses the type size. */
6514 else
6517 /* Find the node to use for errors. */
6524 else
6527 /* Return 0 if no size was specified, either because Esize was not Present or
6528 the specified size was zero. */
6532 /* Get the size as a tree. Give an error if a size was specified, but cannot
6533 be represented as in sizetype. */
6536 {
6541 }
6543 /* Ignore a negative size since that corresponds to our back-annotation.
6544 Also ignore a zero size unless a size clause exists. */
6548 /* The size of objects is always a multiple of a byte. */
6551 {
6555 else
6559 }
6561 /* If this is an integral type or a packed array type, the front-end has
6562 verified the size, so we need not do it here (which would entail
6563 checking against the bounds). However, if this is an aliased object, it
6564 may not be smaller than the type of the object. */
6569 /* If the object is a record that contains a template, add the size of
6570 the template to the specified size. */
6575 /* Modify the size of the type to be that of the maximum size if it has a
6576 discriminant or the size of a thin pointer if this is a fat pointer. */
6582 /* If this is an access type, the minimum size is that given by the smallest
6583 integral mode that's valid for pointers. */
6585 {
6591 ;
6594 }
6596 /* If the size of the object is a constant, the new size must not be
6597 smaller. */
6601 {
6603 post_error_ne_tree
6606 else
6613 post_error_ne_tree_2
6623 }
6626 }
6627 \f
6628 /* Similarly, but both validate and process a value of RM_Size. This
6629 routine is only called for types. */
6631 static void
6633 {
6634 /* Only give an error if a Value_Size clause was explicitly given.
6635 Otherwise, we'd be duplicating an error on the Size clause. */
6636 Node_Id gnat_attr_node
6639 tree size;
6641 /* Get the size as a tree. Do nothing if none was specified, either
6642 because RM_Size was not Present or if the specified size was zero.
6643 Give an error if a size was specified, but cannot be represented as
6644 in sizetype. */
6650 {
6653 gnat_entity);
6656 }
6658 /* Ignore a negative size since that corresponds to our back-annotation.
6659 Also ignore a zero size unless a size clause exists, a Value_Size
6660 clause exists, or this is an integer type, in which case the
6661 front end will have always set it. */
6668 /* If the old size is self-referential, get the maximum size. */
6672 /* If the size of the object is a constant, the new size must not be
6673 smaller (the front end checks this for scalar types). */
6678 {
6680 post_error_ne_tree
6685 }
6687 /* Otherwise, set the RM_Size. */
6698 }
6699 \f
6700 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
6701 If TYPE is the best type, return it. Otherwise, make a new type. We
6702 only support new integral and pointer types. BIASED_P is nonzero if
6703 we are making a biased type. */
6705 static tree
6707 {
6708 tree new_type;
6712 /* If size indicates an error, just return TYPE to avoid propagating the
6713 error. Likewise if it's too large to represent. */
6719 {
6722 /* Only do something if the type is not already the proper size and is
6723 not a packed array type. */
6735 new_type
6747 /* Do something if this is a fat pointer, in which case we
6748 may need to return the thin pointer. */
6750 return
6751 build_pointer_type
6756 /* Only do something if this is a thin pointer, in which case we
6757 may need to return the fat pointer. */
6759 return
6766 }
6769 }
6770 \f
6771 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
6772 a type or object whose present alignment is ALIGN. If this alignment is
6773 valid, return it. Otherwise, give an error and return ALIGN. */
6775 static unsigned int
6777 {
6786 /* Don't worry about checking alignment if alignment was not specified
6787 by the source program and we already posted an error for this entity. */
6792 /* Within GCC, an alignment is an integer, so we must make sure a value is
6793 specified that fits in that range. Also, there is an upper bound to
6794 alignments we can support/allow. */
6806 else
6810 }
6812 /* Return the smallest alignment not less than SIZE. */
6814 static unsigned int
6816 {
6818 }
6819 \f
6820 /* Verify that OBJECT, a type or decl, is something we can implement
6821 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
6822 if we require atomic components. */
6824 static void
6826 {
6828 Node_Id gnat_node;
6831 tree size;
6833 /* There are three case of what OBJECT can be. It can be a type, in which
6834 case we take the size, alignment and mode from the type. It can be a
6835 declaration that was indirect, in which case the relevant values are
6836 that of the type being pointed to, or it can be a normal declaration,
6837 in which case the values are of the decl. The code below assumes that
6838 OBJECT is either a type or a decl. */
6840 {
6844 }
6846 {
6850 }
6851 else
6852 {
6856 }
6858 /* Consider all floating-point types atomic and any types that that are
6859 represented by integers no wider than a machine word. */
6866 /* For the moment, also allow anything that has an alignment equal
6867 to its size and which is smaller than a word. */
6875 {
6883 }
6888 else
6891 }
6892 \f
6893 /* Check if FTYPE1 and FTYPE2, two potentially different function type nodes,
6894 have compatible signatures so that a call using one type may be safely
6895 issued if the actual target function type is the other. Return 1 if it is
6896 the case, 0 otherwise, and post errors on the incompatibilities.
6898 This is used when an Ada subprogram is mapped onto a GCC builtin, to ensure
6899 that calls to the subprogram will have arguments suitable for the later
6900 underlying builtin expansion. */
6902 static int
6904 {
6905 /* As of now, we only perform very trivial tests and consider it's the
6906 programmer's responsibility to ensure the type correctness in the Ada
6907 declaration, as in the regular Import cases.
6909 Mismatches typically result in either error messages from the builtin
6910 expander, internal compiler errors, or in a real call sequence. This
6911 should be refined to issue diagnostics helping error detection and
6912 correction. */
6914 /* Almost fake test, ensuring a use of each argument. */
6919 }
6920 \f
6921 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new
6922 type with all size expressions that contain F updated by replacing F
6923 with R. If F is NULL_TREE, always make a new RECORD_TYPE, even if
6924 nothing has changed. */
6926 tree
6928 {
6930 tree tem;
6933 {
6939 {
6948 SET_TYPE_INDEX_TYPE
6951 }
6958 {
6972 }
6986 /* Don't know how to do these yet. */
6990 {
7005 /* If we had bounded the sizes of T by a constant, bound the sizes of
7006 NEW by the same constant. */
7016 }
7021 {
7022 tree field;
7023 bool changed_field
7030 /* Start out with no fields, make new fields, and chain them
7031 in. If we haven't actually changed the type of any field,
7032 discard everything we've done and return the old type. */
7038 {
7049 /* If this is an internal field and the type of this field is
7050 a UNION_TYPE or RECORD_TYPE with no elements, ignore it. If
7051 the type just has one element, treat that as the field.
7052 But don't do this if we are processing a QUAL_UNION_TYPE. */
7057 {
7062 {
7063 tree next_new_field
7066 /* Make sure omitting the union doesn't change
7067 the layout. */
7070 }
7071 }
7078 /* If the size of the old field was set at a constant,
7079 propagate the size in case the type's size was variable.
7080 (This occurs in the case of a variant or discriminated
7081 record with a default size used as a field of another
7082 record.) */
7091 {
7097 /* Do the substitution inside the qualifier and if we find
7098 that this field will not be present, omit it. */
7103 }
7107 else
7112 /* If this is a qualified type and this field will always be
7113 present, we are done. */
7117 }
7119 /* If this used to be a qualified union type, but we now know what
7120 field will be present, make this a normal union. */
7131 /* If the size was originally a constant use it. */
7134 {
7138 }
7141 }
7145 }
7146 }
7147 \f
7148 /* Return the "RM size" of GNU_TYPE. This is the actual number of bits
7149 needed to represent the object. */
7151 tree
7153 {
7154 /* For integer types, this is the precision. For record types, we store
7155 the size explicitly. For other types, this is just the size. */
7161 /* Return the rm_size of the actual data plus the size of the template. */
7162 return
7172 else
7174 }
7175 \f
7176 /* Return an identifier representing the external name to be used for
7177 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
7178 and the specified suffix. */
7180 tree
7182 {
7191 /* A variable using the Stdcall convention (meaning we are running
7192 on a Windows box) live in a DLL. Here we adjust its name to use
7193 the jump-table, the _imp__NAME contains the address for the NAME
7194 variable. */
7197 {
7204 }
7207 }
7209 /* Return the name to be used for GNAT_ENTITY. If a type, create a
7210 fully-qualified name, possibly with type information encoding.
7211 Otherwise, return the name. */
7213 tree
7215 {
7218 }
7220 /* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
7221 string, return a new IDENTIFIER_NODE that is the concatenation of
7222 the name in GNU_ID and SUFFIX. */
7224 tree
7226 {
7235 }