| blob | 14fcd634b610ad400520cb87c4de1de4961b9262 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2008, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License along with GCC; see the file COPYING3. If not see *
19 * <http://www.gnu.org/licenses/>. *
20 * *
21 * GNAT was originally developed by the GNAT team at New York University. *
22 * Extensive contributions were provided by Ada Core Technologies Inc. *
23 * *
24 ****************************************************************************/
56 #ifndef MAX_FIXED_MODE_SIZE
57 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
58 #endif
60 /* Convention_Stdcall should be processed in a specific way on Windows targets
61 only. The macro below is a helper to avoid having to check for a Windows
62 specific attribute throughout this unit. */
64 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
65 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
66 #else
67 #define Has_Stdcall_Convention(E) (0)
68 #endif
70 /* Stack realignment for functions with foreign conventions is provided on a
71 per back-end basis now, as it is handled by the prologue expanders and not
72 as part of the function's body any more. It might be requested by way of a
73 dedicated function type attribute on the targets that support it.
75 We need a way to avoid setting the attribute on the targets that don't
76 support it and use FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN for this purpose.
78 It is defined on targets where the circuitry is available, and indicates
79 whether the realignment is needed for 'main'. We use this to decide for
80 foreign subprograms as well.
82 It is not defined on targets where the circuitry is not implemented, and
83 we just never set the attribute in these cases.
85 Whether it is defined on all targets that would need it in theory is
86 not entirely clear. We currently trust the base GCC settings for this
87 purpose. */
89 #ifndef FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN
90 #define FORCE_PREFERRED_STACK_BOUNDARY_IN_MAIN 0
91 #endif
93 struct incomplete
94 {
96 tree old_type;
97 Entity_Id full_type;
98 };
100 /* These variables are used to defer recursively expanding incomplete types
101 while we are processing an array, a record or a subprogram type. */
105 /* This variable is used to delay expanding From_With_Type types until the
106 end of the spec. */
109 /* These variables are used to defer finalizing types. The element of the
110 list is the TYPE_DECL associated with the type. */
114 /* A hash table used to cache the result of annotate_value. */
148 /* Return true if GNAT_ADDRESS is a compile time known value.
149 In particular catch System'To_Address. */
151 static bool
153 {
157 }
159 /* Given GNAT_ENTITY, an entity in the incoming GNAT tree, return a
160 GCC type corresponding to that entity. GNAT_ENTITY is assumed to
161 refer to an Ada type. */
163 tree
165 {
166 tree gnu_decl;
168 /* The back end never attempts to annotate generic types */
172 /* Convert the ada entity type into a GCC TYPE_DECL node. */
176 }
177 \f
178 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
179 entity, this routine returns the equivalent GCC tree for that entity
180 (an ..._DECL node) and associates the ..._DECL node with the input GNAT
181 defining identifier.
183 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
184 initial value (in GCC tree form). This is optional for variables.
185 For renamed entities, GNU_EXPR gives the object being renamed.
187 DEFINITION is nonzero if this call is intended for a definition. This is
188 used for separate compilation where it necessary to know whether an
189 external declaration or a definition should be created if the GCC equivalent
190 was not created previously. The value of 1 is normally used for a nonzero
191 DEFINITION, but a value of 2 is used in special circumstances, defined in
192 the code. */
194 tree
196 {
198 tree gnu_entity_id;
200 /* Contains the gnu XXXX_DECL tree node which is equivalent to the input
201 GNAT tree. This node will be associated with the GNAT node by calling
202 the save_gnu_tree routine at the end of the `switch' statement. */
204 /* true if we have already saved gnu_decl as a gnat association. */
206 /* Nonzero if we incremented defer_incomplete_level. */
208 /* Nonzero if we incremented force_global. */
210 /* Nonzero if we should check to see if elaborated during processing. */
212 /* Nonzero if we made GNU_DECL and its type here. */
218 Entity_Id gnat_temp;
219 unsigned int esize
229 bool imported_p
233 /* Since a use of an Itype is a definition, process it as such if it
234 is not in a with'ed unit. */
239 {
240 /* Ensure that we are in a subprogram mentioned in the Scope
241 chain of this entity, our current scope is global,
242 or that we encountered a task or entry (where we can't currently
243 accurately check scoping). */
246 {
249 }
253 {
258 gnat_temp
270 && (current_function_decl
272 {
275 }
276 }
278 /* This abort means the entity "gnat_entity" has an incorrect scope,
279 i.e. that its scope does not correspond to the subprogram in which
280 it is declared */
282 }
284 /* If this is entity 0, something went badly wrong. */
287 /* If we've already processed this entity, return what we got last time.
288 If we are defining the node, we should not have already processed it.
289 In that case, we will abort below when we try to save a new GCC tree for
290 this object. We also need to handle the case of getting a dummy type
291 when a Full_View exists. */
295 {
302 {
308 }
311 }
313 /* If this is a numeric or enumeral type, or an access type, a nonzero
314 Esize must be specified unless it was specified by the programmer. */
323 /* Likewise, RM_Size must be specified for all discrete and fixed-point
324 types. */
328 /* Get the name of the entity and set up the line number and filename of
329 the original definition for use in any decl we make. */
333 /* If we get here, it means we have not yet done anything with this
334 entity. If we are not defining it here, it must be external,
335 otherwise we should have defined it already. */
342 /* For cases when we are not defining (i.e., we are referencing from
343 another compilation unit) Public entities, show we are at global level
344 for the purpose of computing scopes. Don't do this for components or
345 discriminants since the relevant test is whether or not the record is
346 being defined. But do this for Imported functions or procedures in
347 all cases. */
355 /* Handle any attributes directly attached to the entity. */
359 /* Machine_Attributes on types are expected to be propagated to subtypes.
360 The corresponding Gigi_Rep_Items are only attached to the first subtype
361 though, so we handle the propagation here. */
368 {
370 /* If this is a use of a deferred constant without address clause,
371 get its full definition. */
375 {
376 gnu_decl
380 }
382 /* If we have an external constant that we are not defining, get the
383 expression that is was defined to represent. We may throw that
384 expression away later if it is not a constant. Do not retrieve the
385 expression if it is an aggregate or allocator, because in complex
386 instantiation contexts it may not be expanded */
396 /* Ignore deferred constant definitions without address clause since
397 they are processed fully in the front-end. If No_Initialization
398 is set, this is not a deferred constant but a constant whose value
399 is built manually. And constants that are renamings are handled
400 like variables. */
402 && !gnu_expr
406 {
410 }
412 /* Ignore constant definitions already marked with the error node. See
413 the N_Object_Declaration case of gnat_to_gnu for the rationale. */
415 && gnu_expr
418 {
421 }
426 /* We used to special case VMS exceptions here to directly map them to
427 their associated condition code. Since this code had to be masked
428 dynamically to strip off the severity bits, this caused trouble in
429 the GCC/ZCX case because the "type" pointers we store in the tables
430 have to be static. We now don't special case here anymore, and let
431 the regular processing take place, which leaves us with a regular
432 exception data object for VMS exceptions too. The condition code
433 mapping is taken care of by the front end and the bitmasking by the
434 runtime library. */
439 {
440 /* The GNAT record where the component was defined. */
443 /* If the variable is an inherited record component (in the case of
444 extended record types), just return the inherited entity, which
445 must be a FIELD_DECL. Likewise for discriminants.
446 For discriminants of untagged records which have explicit
447 stored discriminants, return the entity for the corresponding
448 stored discriminant. Also use Original_Record_Component
449 if the record has a private extension. */
453 {
454 gnu_decl
459 }
461 /* If the enclosing record has explicit stored discriminants,
462 then it is an untagged record. If the Corresponding_Discriminant
463 is not empty then this must be a renamed discriminant and its
464 Original_Record_Component must point to the corresponding explicit
465 stored discriminant (i.e., we should have taken the previous
466 branch). */
470 {
471 /* A tagged record has no explicit stored discriminants. */
475 gnu_decl
480 }
484 {
489 }
491 /* If the enclosing record has explicit stored discriminants, then
492 it is an untagged record. If the Corresponding_Discriminant
493 is not empty then this must be a renamed discriminant and its
494 Original_Record_Component must point to the corresponding explicit
495 stored discriminant (i.e., we should have taken the first
496 branch). */
503 /* Otherwise, if we are not defining this and we have no GCC type
504 for the containing record, make one for it. Then we should
505 have made our own equivalent. */
507 {
508 /* ??? If this is in a record whose scope is a protected
509 type and we have an Original_Record_Component, use it.
510 This is a workaround for major problems in protected type
511 handling. */
518 {
519 gnu_decl
525 }
531 }
533 else
534 /* Here we have no GCC type and this is a reference rather than a
535 definition. This should never happen. Most likely the cause is
536 reference before declaration in the gnat tree for gnat_entity. */
538 }
544 /* Simple variables, loop variables, Out parameters, and exceptions. */
545 object:
546 {
548 bool const_flag
561 tree gnu_object_size;
564 {
568 else
570 }
572 /* Get the type after elaborating the renamed object. */
575 /* For a debug renaming declaration, build a pure debug entity. */
577 {
578 rtx addr;
580 /* The (MEM (CONST (0))) pattern is prescribed by STABS. */
583 else
588 }
590 /* If this is a loop variable, its type should be the base type.
591 This is because the code for processing a loop determines whether
592 a normal loop end test can be done by comparing the bounds of the
593 loop against those of the base type, which is presumed to be the
594 size used for computation. But this is not correct when the size
595 of the subtype is smaller than the type. */
599 /* Reject non-renamed objects whose types are unconstrained arrays or
600 any object whose type is a dummy type or VOID_TYPE. */
606 {
609 force_global--;
611 }
613 /* If an alignment is specified, use it if valid. Note that
614 exceptions are objects but don't have alignments. We must do this
615 before we validate the size, since the alignment can affect the
616 size. */
618 {
624 }
626 /* If we are defining the object, see if it has a Size value and
627 validate it if so. If we are not defining the object and a Size
628 clause applies, simply retrieve the value. We don't want to ignore
629 the clause and it is expected to have been validated already. Then
630 get the new type, if any. */
639 {
640 gnu_type
646 }
648 /* If this object has self-referential size, it must be a record with
649 a default value. We are supposed to allocate an object of the
650 maximum size in this case unless it is a constant with an
651 initializing expression, in which case we can get the size from
652 that. Note that the resulting size may still be a variable, so
653 this may end up with an indirect allocation. */
656 {
658 {
661 {
662 /* If the initializing expression is itself a constant,
663 despite having a nominal type with self-referential
664 size, we can get the size directly from it. */
667 == RECORD_TYPE
668 && TYPE_IS_PADDING_P
672 || DECL_READONLY_ONCE_ELAB
675 else
676 gnu_size
678 }
679 else
681 }
682 /* We may have no GNU_EXPR because No_Initialization is
683 set even though there's an Expression. */
688 gnu_size
690 (Etype
692 else
693 {
696 }
697 }
699 /* If the size is zero bytes, make it one byte since some linkers have
700 trouble with zero-sized objects. If the object will have a
701 template, that will make it nonzero so don't bother. Also avoid
702 doing that for an object renaming or an object with an address
703 clause, as we would lose useful information on the view size
704 (e.g. for null array slices) and we are not allocating the object
705 here anyway. */
718 /* If this is an object with no specified size and alignment, and
719 if either it is atomic or we are not optimizing alignment for
720 space and it is composite and not an exception, an Out parameter
721 or a reference to another object, and the size of its type is a
722 constant, set the alignment to the smallest one which is not
723 smaller than the size, with an appropriate cap. */
731 && !imported_p
735 {
736 /* No point in jumping through all the hoops needed in order
737 to support BIGGEST_ALIGNMENT if we don't really have to.
738 So we cap to the smallest alignment that corresponds to
739 a known efficient memory access pattern of the target. */
741 ? BIGGEST_ALIGNMENT
747 else
750 /* But make sure not to under-align the object. */
754 /* And honor the minimum valid atomic alignment, if any. */
755 #ifdef MINIMUM_ATOMIC_ALIGNMENT
758 #endif
759 }
761 /* If the object is set to have atomic components, find the component
762 type and validate it.
764 ??? Note that we ignore Has_Volatile_Components on objects; it's
765 not at all clear what to do in that case. */
768 {
777 }
779 /* Now check if the type of the object allows atomic access. Note
780 that we must test the type, even if this object has size and
781 alignment to allow such access, because we will be going
782 inside the padded record to assign to the object. We could fix
783 this by always copying via an intermediate value, but it's not
784 clear it's worth the effort. */
788 /* If this is an aliased object with an unconstrained nominal subtype,
789 make a type that includes the template. */
793 {
794 tree gnu_fat
797 gnu_type
801 }
803 #ifdef MINIMUM_ATOMIC_ALIGNMENT
804 /* If the size is a constant and no alignment is specified, force
805 the alignment to be the minimum valid atomic alignment. The
806 restriction on constant size avoids problems with variable-size
807 temporaries; if the size is variable, there's no issue with
808 atomic access. Also don't do this for a constant, since it isn't
809 necessary and can interfere with constant replacement. Finally,
810 do not do it for Out parameters since that creates an
811 size inconsistency with In parameters. */
820 #endif
822 /* Make a new type with the desired size and alignment, if needed.
823 But do not take into account alignment promotions to compute the
824 size of the object. */
831 /* If this is a renaming, avoid as much as possible to create a new
832 object. However, in several cases, creating it is required.
833 This processing needs to be applied to the raw expression so
834 as to make it more likely to rename the underlying object. */
836 {
839 /* If the renamed object had padding, strip off the reference
840 to the inner object and reset our type. */
843 == RECORD_TYPE
845 /* Strip useless conversions around the object. */
847 {
850 }
852 /* Case 1: If this is a constant renaming stemming from a function
853 call, treat it as a normal object whose initial value is what
854 is being renamed. RM 3.3 says that the result of evaluating a
855 function call is a constant object. As a consequence, it can
856 be the inner object of a constant renaming. In this case, the
857 renaming must be fully instantiated, i.e. it cannot be a mere
858 reference to (part of) an existing object. */
860 {
866 }
868 /* Otherwise, see if we can proceed with a stabilized version of
869 the renamed entity or if we need to make a new object. */
871 {
875 /* Case 2: If the renaming entity need not be materialized and
876 the renamed expression is something we can stabilize, use
877 that for the renaming. At the global level, we can only do
878 this if we know no SAVE_EXPRs need be made, because the
879 expression we return might be used in arbitrary conditional
880 branches so we must force the SAVE_EXPRs evaluation
881 immediately and this requires a function context. */
886 {
887 maybe_stable_expr
891 {
893 /* ??? No DECL_EXPR is created so we need to mark
894 the expression manually lest it is shared. */
900 }
902 /* The stabilization failed. Keep maybe_stable_expr
903 untouched here to let the pointer case below know
904 about that failure. */
905 }
907 /* Case 3: If this is a constant renaming and creating a
908 new object is allowed and cheap, treat it as a normal
909 object whose initial value is what is being renamed. */
911 ;
913 /* Case 4: Make this into a constant pointer to the object we
914 are to rename and attach the object to the pointer if it is
915 something we can stabilize.
917 From the proper scope, attached objects will be referenced
918 directly instead of indirectly via the pointer to avoid
919 subtle aliasing problems with non-addressable entities.
920 They have to be stable because we must not evaluate the
921 variables in the expression every time the renaming is used.
922 The pointer is called a "renaming" pointer in this case.
924 In the rare cases where we cannot stabilize the renamed
925 object, we just make a "bare" pointer, and the renamed
926 entity is always accessed indirectly through it. */
927 else
928 {
933 /* If the previous attempt at stabilizing failed, there
934 is no point in trying again and we reuse the result
935 without attaching it to the pointer. In this case it
936 will only be used as the initializing expression of
937 the pointer and thus needs no special treatment with
938 regard to multiple evaluations. */
940 ;
942 /* Otherwise, try to stabilize and attach the expression
943 to the pointer if the stabilization succeeds.
945 Note that this might introduce SAVE_EXPRs and we don't
946 check whether we're at the global level or not. This
947 is fine since we are building a pointer initializer and
948 neither the pointer nor the initializing expression can
949 be accessed before the pointer elaboration has taken
950 place in a correct program.
952 These SAVE_EXPRs will be evaluated at the right place
953 by either the evaluation of the initializer for the
954 non-global case or the elaboration code for the global
955 case, and will be attached to the elaboration procedure
956 in the latter case. */
957 else
958 {
959 maybe_stable_expr
965 /* Attaching is actually performed downstream, as soon
966 as we have a VAR_DECL for the pointer we make. */
967 }
969 gnu_expr
974 }
975 }
976 }
978 /* Make a volatile version of this object's type if we are to make
979 the object volatile. We also interpret 13.3(19) conservatively
980 and disallow any optimizations for an object covered by it. */
983 /* Exclude exported constants created by the compiler,
984 which should boil down to static dispatch tables and
985 make it possible to put them in read-only memory. */
994 /* If we are defining an aliased object whose nominal subtype is
995 unconstrained, the object is a record that contains both the
996 template and the object. If there is an initializer, it will
997 have already been converted to the right type, but we need to
998 create the template if there is no initializer. */
1000 && !gnu_expr
1003 /* Beware that padding might have been introduced
1004 via maybe_pad_type above. */
1007 == RECORD_TYPE
1008 && TYPE_CONTAINS_TEMPLATE_P
1010 {
1011 tree template_field
1016 gnu_expr
1017 = gnat_build_constructor
1019 tree_cons
1023 NULL_TREE),
1024 NULL_TREE));
1025 }
1027 /* Convert the expression to the type of the object except in the
1028 case where the object's type is unconstrained or the object's type
1029 is a padded record whose field is of self-referential size. In
1030 the former case, converting will generate unnecessary evaluations
1031 of the CONSTRUCTOR to compute the size and in the latter case, we
1032 want to only copy the actual data. */
1038 && (CONTAINS_PLACEHOLDER_P
1042 /* If this is a pointer and it does not have an initializing
1043 expression, initialize it to NULL, unless the object is
1044 imported. */
1050 /* If we are defining the object and it has an Address clause, we must
1051 either get the address expression from the saved GCC tree for the
1052 object if it has a Freeze node, or elaborate the address expression
1053 here since the front-end has guaranteed that the elaboration has no
1054 effects in this case. */
1056 {
1057 tree gnu_address
1064 /* Ignore the size. It's either meaningless or was handled
1065 above. */
1067 /* Convert the type of the object to a reference type that can
1068 alias everything as per 13.3(19). */
1069 gnu_type
1077 /* If this is a deferred constant, the initializer is attached to
1078 the full view. */
1080 gnu_expr
1081 = gnat_to_gnu
1084 /* If we don't have an initializing expression for the underlying
1085 variable, the initializing expression for the pointer is the
1086 specified address. Otherwise, we have to make a COMPOUND_EXPR
1087 to assign both the address and the initial value. */
1090 else
1091 gnu_expr
1093 build_binary_op
1096 gnu_address),
1097 gnu_expr),
1098 gnu_address);
1099 }
1101 /* If it has an address clause and we are not defining it, mark it
1102 as an indirect object. Likewise for Stdcall objects that are
1103 imported. */
1107 {
1108 /* Convert the type of the object to a reference type that can
1109 alias everything as per 13.3(19). */
1110 gnu_type
1114 /* No point in taking the address of an initializing expression
1115 that isn't going to be used. */
1118 /* If it has an address clause whose value is known at compile
1119 time, make the object a CONST_DECL. This will avoid a
1120 useless dereference. */
1122 {
1123 Node_Id gnat_address
1127 {
1130 }
1131 }
1134 }
1136 /* If we are at top level and this object is of variable size,
1137 make the actual type a hidden pointer to the real type and
1138 make the initializer be a memory allocation and initialization.
1139 Likewise for objects we aren't defining (presumed to be
1140 external references from other packages), but there we do
1141 not set up an initialization.
1143 If the object's size overflows, make an allocator too, so that
1144 Storage_Error gets raised. Note that we will never free
1145 such memory, so we presume it never will get allocated. */
1150 || (gnu_size
1154 {
1160 /* In case this was a aliased object whose nominal subtype is
1161 unconstrained, the pointer above will be a thin pointer and
1162 build_allocator will automatically make the template.
1164 If we have a template initializer only (that we made above),
1165 pretend there is none and rely on what build_allocator creates
1166 again anyway. Otherwise (if we have a full initializer), get
1167 the data part and feed that to build_allocator.
1169 If we are elaborating a mutable object, tell build_allocator to
1170 ignore a possibly simpler size from the initializer, if any, as
1171 we must allocate the maximum possible size in this case. */
1174 {
1179 {
1180 gnu_alloc_type
1187 else
1188 gnu_expr
1189 = build_component_ref
1193 }
1199 gnat_entity);
1203 }
1204 else
1205 {
1208 }
1209 }
1211 /* If this object would go into the stack and has an alignment larger
1212 than the largest stack alignment the back-end can honor, resort to
1213 a variable of "aligning type". */
1216 {
1217 /* Create the new variable. No need for extra room before the
1218 aligned field as this is in automatic storage. */
1219 tree gnu_new_type
1223 tree gnu_new_var
1228 /* Initialize the aligned field if we have an initializer. */
1230 add_stmt_with_node
1232 build_component_ref
1235 gnu_expr),
1236 gnat_entity);
1238 /* And setup this entity as a reference to the aligned field. */
1240 gnu_expr
1241 = build_unary_op
1249 }
1255 /* Convert the expression to the type of the object except in the
1256 case where the object's type is unconstrained or the object's type
1257 is a padded record whose field is of self-referential size. In
1258 the former case, converting will generate unnecessary evaluations
1259 of the CONSTRUCTOR to compute the size and in the latter case, we
1260 want to only copy the actual data. */
1266 && (CONTAINS_PLACEHOLDER_P
1270 /* If this name is external or there was a name specified, use it,
1271 unless this is a VMS exception object since this would conflict
1272 with the symbol we need to export in addition. Don't use the
1273 Interface_Name if there is an address clause (see CD30005). */
1282 /* If this is constant initialized to a static constant and the
1283 object has an aggregate type, force it to be statically
1284 allocated. This will avoid an initialization copy. */
1303 {
1306 {
1309 }
1310 }
1322 gnat_entity);
1324 /* If we are defining an Out parameter and we're not optimizing,
1325 create a fake PARM_DECL for debugging purposes and make it
1326 point to the VAR_DECL. Suppress debug info for the latter
1327 but make sure it will still live on the stack so it can be
1328 accessed from within the debugger through the PARM_DECL. */
1330 {
1337 else
1340 }
1342 /* If this is a public constant or we're not optimizing and we're not
1343 making a VAR_DECL for it, make one just for export or debugger use.
1344 Likewise if the address is taken or if either the object or type is
1345 aliased. Make an external declaration for a reference, unless this
1346 is a Standard entity since there no real symbol at the object level
1347 for these. */
1352 || !optimize
1356 {
1357 tree gnu_corr_var
1361 gnat_entity);
1365 /* As debugging information will be generated for the variable,
1366 do not generate information for the constant. */
1368 }
1370 /* If this is declared in a block that contains a block with an
1371 exception handler, we must force this variable in memory to
1372 suppress an invalid optimization. */
1379 /* Back-annotate Alignment and Esize of the object if not already
1380 known, except for when the object is actually a pointer to the
1381 real object, since alignment and size of a pointer don't have
1382 anything to do with those of the designated object. Note that
1383 we pick the values of the type, not those of the object, to
1384 shield ourselves from low-level platform-dependent adjustments
1385 like alignment promotion. This is both consistent with all the
1386 treatment above, where alignment and size are set on the type of
1387 the object and not on the object directly, and makes it possible
1388 to support confirming representation clauses in all cases. */
1395 {
1398 gnu_object_size
1402 }
1403 }
1407 /* Return a TYPE_DECL for "void" that we previously made. */
1412 /* A special case, for the types Character and Wide_Character in
1413 Standard, we do not list all the literals. So if the literals
1414 are not specified, make this an unsigned type. */
1416 {
1420 /* Set TYPE_STRING_FLAG for Ada Character and Wide_Character types.
1421 This is needed by the DWARF-2 back-end to distinguish between
1422 unsigned integer types and character types. */
1425 }
1427 /* Normal case of non-character type, or non-Standard character type */
1428 {
1429 /* Here we have a list of enumeral constants in First_Literal.
1430 We make a CONST_DECL for each and build into GNU_LITERAL_LIST
1431 the list to be places into TYPE_FIELDS. Each node in the list
1432 is a TREE_LIST node whose TREE_VALUE is the literal name
1433 and whose TREE_PURPOSE is the value of the literal.
1435 Esize contains the number of bits needed to represent the enumeral
1436 type, Type_Low_Bound also points to the first literal and
1437 Type_High_Bound points to the last literal. */
1439 Entity_Id gnat_literal;
1444 else
1452 {
1454 gnu_type);
1455 tree gnu_literal
1463 }
1467 /* Note that the bounds are updated at the end of this function
1468 because to avoid an infinite recursion when we get the bounds of
1469 this type, since those bounds are objects of this type. */
1470 }
1476 /* For integer types, just make a signed type the appropriate number
1477 of bits. */
1482 /* For modular types, make the unsigned type of the proper number of
1483 bits and then set up the modulus, if required. */
1484 {
1486 tree gnu_modulus;
1492 /* Find the smallest mode at least ESIZE bits wide and make a class
1493 using that mode. */
1498 ;
1505 /* Get the modulus in this type. If it overflows, assume it is because
1506 it is equal to 2**Esize. Note that there is no overflow checking
1507 done on unsigned type, so we detect the overflow by looking for
1508 a modulus of zero, which is otherwise invalid. */
1512 {
1517 }
1519 /* If we have to set TYPE_PRECISION different from its natural value,
1520 make a subtype to do do. Likewise if there is a modulus and
1521 it is not one greater than TYPE_MAX_VALUE. */
1525 {
1543 }
1544 }
1553 /* For integral subtypes, we make a new INTEGER_TYPE. Note
1554 that we do not want to call build_range_type since we would
1555 like each subtype node to be distinct. This will be important
1556 when memory aliasing is implemented.
1558 The TREE_TYPE field of the INTEGER_TYPE we make points to the
1559 parent type; this fact is used by the arithmetic conversion
1560 functions.
1562 We elaborate the Ancestor_Subtype if it is not in the current
1563 unit and one of our bounds is non-static. We do this to ensure
1564 consistent naming in the case where several subtypes share the same
1565 bounds by always elaborating the first such subtype first, thus
1566 using its name. */
1579 /* Set the precision to the Esize except for bit-packed arrays and
1580 subtypes of Standard.Boolean. */
1583 {
1586 }
1595 gnat_entity,
1602 gnat_entity,
1606 /* One of the above calls might have caused us to be elaborated,
1607 so don't blow up if so. */
1609 {
1612 }
1617 /* This should be an unsigned type if the lower bound is constant
1618 and non-negative or if the base type is unsigned; a signed type
1619 otherwise. */
1629 /* Inherit our alias set from what we're a subtype of. Subtypes
1630 are not different types and a pointer can designate any instance
1631 within a subtype hierarchy. */
1634 /* If the type we are dealing with is to represent a packed array,
1635 we need to have the bits left justified on big-endian targets
1636 and right justified on little-endian targets. We also need to
1637 ensure that when the value is read (e.g. for comparison of two
1638 such values), we only get the good bits, since the unused bits
1639 are uninitialized. Both goals are accomplished by wrapping the
1640 modular value in an enclosing struct. */
1643 {
1645 tree gnu_field;
1652 /* Propagate the alignment of the modular type to the record.
1653 This means that bitpacked arrays have "ceil" alignment for
1654 their size, which may seem counter-intuitive but makes it
1655 possible to easily overlay them on modular types. */
1659 /* Create a stripped-down declaration of the original type, mainly
1660 for debugging. */
1664 /* Don't notify the field as "addressable", since we won't be taking
1665 it's address and it would prevent create_field_decl from making a
1666 bitfield. */
1675 }
1677 /* If the type we are dealing with has got a smaller alignment than the
1678 natural one, we need to wrap it up in a record type and under-align
1679 the latter. We reuse the padding machinery for this purpose. */
1684 {
1686 tree gnu_field;
1694 /* Create a stripped-down declaration of the original type, mainly
1695 for debugging. */
1699 /* Don't notify the field as "addressable", since we won't be taking
1700 it's address and it would prevent create_field_decl from making a
1701 bitfield. */
1710 }
1712 /* Otherwise reset the alignment lest we computed it above. */
1713 else
1719 /* If this is a VAX floating-point type, use an integer of the proper
1720 size. All the operations will be handled with ASM statements. */
1722 {
1727 sizetype));
1729 }
1731 /* The type of the Low and High bounds can be our type if this is
1732 a type from Standard, so set them at the end of the function. */
1740 {
1743 }
1745 {
1772 /* One of the above calls might have caused us to be elaborated,
1773 so don't blow up if so. */
1775 {
1778 }
1782 /* Inherit our alias set from what we're a subtype of, as for
1783 integer subtypes. */
1785 }
1788 /* Array and String Types and Subtypes
1790 Unconstrained array types are represented by E_Array_Type and
1791 constrained array types are represented by E_Array_Subtype. There
1792 are no actual objects of an unconstrained array type; all we have
1793 are pointers to that type.
1795 The following fields are defined on array types and subtypes:
1797 Component_Type Component type of the array.
1798 Number_Dimensions Number of dimensions (an int).
1799 First_Index Type of first index. */
1803 {
1809 int firstdim
1811 int nextdim
1818 tree gnu_max_size_unit;
1819 Entity_Id gnat_ind_subtype;
1820 Entity_Id gnat_ind_base_subtype;
1821 tree gnu_template_reference;
1822 tree tem;
1827 /* Make a node for the array. If we are not defining the array
1828 suppress expanding incomplete types. */
1834 /* Build the fat pointer type. Use a "void *" object instead of
1835 a pointer to the array type since we don't have the array type
1836 yet (it will reference the fat pointer via the bounds). */
1839 ptr_void_type_node,
1842 gnu_ptr_template,
1845 /* Make sure we can put this into a register. */
1848 /* Do not finalize this record type since the types of its fields
1849 are still incomplete at this point. */
1853 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1854 is the fat pointer. This will be used to access the individual
1855 fields once we build them. */
1859 gnu_template_reference
1863 /* Now create the GCC type for each index and add the fields for
1864 that index to the template. */
1866 gnat_ind_base_subtype
1872 {
1874 tree gnu_ind_subtype
1876 tree gnu_base_subtype
1878 tree gnu_base_min
1880 tree gnu_base_max
1884 /* Make the FIELD_DECLs for the minimum and maximum of this
1885 type and then make extractions of that field from the
1886 template. */
1889 gnu_ind_subtype,
1893 gnu_ind_subtype,
1902 /* We can't use build_component_ref here since the template
1903 type isn't complete yet. */
1906 NULL_TREE);
1909 NULL_TREE);
1912 /* Make a range type with the new ranges, but using
1913 the Ada subtype. Then we convert to sizetype. */
1919 gnat_entity);
1920 /* Update the maximum size of the array, in elements. */
1921 gnu_max_size
1925 gnu_base_min)));
1929 }
1932 gnu_template_fields
1935 /* Install all the fields into the template. */
1939 /* Now make the array of arrays and update the pointer to the array
1940 in the fat pointer. Note that it is the first field. */
1943 /* Try to get a smaller form of the component if needed. */
1956 /* Get and validate any specified Component_Size, but if Packed,
1957 ignore it since the front end will have taken care of it. */
1958 gnu_comp_size
1960 gnat_entity,
1965 /* If the component type is a RECORD_TYPE that has a self-referential
1966 size, use the maximum size. */
1972 {
1973 tree orig_tem;
1978 /* If a padding record was made, declare it now since it will
1979 never be declared otherwise. This is necessary to ensure
1980 that its subtrees are properly marked. */
1984 }
1990 /* If Component_Size is not already specified, annotate it with the
1991 size of the component. */
2001 gnu_max_size),
2005 {
2010 }
2012 /* If an alignment is specified, use it if valid. But ignore it for
2013 types that represent the unpacked base type for packed arrays. If
2014 the alignment was requested with an explicit user alignment clause,
2015 state so. */
2018 {
2025 }
2031 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
2032 corresponding fat pointer. */
2039 /* If the maximum size doesn't overflow, use it. */
2054 /* Give the fat pointer type a name. */
2059 /* Create the type to be used as what a thin pointer designates: an
2060 record type for the object and its template with the field offsets
2061 shifted to have the template at a negative offset. */
2069 /* Give the thin pointer type a name. */
2073 gnat_entity);
2074 }
2080 /* This is the actual data type for array variables. Multidimensional
2081 arrays are implemented in the gnu tree as arrays of arrays. Note
2082 that for the moment arrays which have sparse enumeration subtypes as
2083 index components create sparse arrays, which is obviously space
2084 inefficient but so much easier to code for now.
2086 Also note that the subtype never refers to the unconstrained
2087 array type, which is somewhat at variance with Ada semantics.
2089 First check to see if this is simply a renaming of the array
2090 type. If so, the result is the array type. */
2095 else
2096 {
2099 int first_dim
2102 int next_dim
2104 Entity_Id gnat_ind_subtype;
2105 Entity_Id gnat_ind_base_subtype;
2110 tree gnu_max_size_unit;
2114 /* First create the gnu types for each index. Create types for
2115 debugging information to point to the index types if the
2116 are not integer types, have variable bounds, or are
2117 wider than sizetype. */
2120 gnat_ind_base_subtype
2126 {
2127 tree gnu_index_subtype
2129 tree gnu_min
2131 tree gnu_max
2133 tree gnu_base_subtype
2135 tree gnu_base_min
2137 tree gnu_base_max
2140 tree gnu_base_base_min
2142 tree gnu_base_base_max
2144 tree gnu_high;
2145 tree gnu_this_max;
2147 /* If the minimum and maximum values both overflow in
2148 SIZETYPE, but the difference in the original type
2149 does not overflow in SIZETYPE, ignore the overflow
2150 indications. */
2158 && (!TREE_OVERFLOW
2162 {
2165 }
2167 /* Similarly, if the range is null, use bounds of 1..0 for
2168 the sizetype bounds. */
2180 /* Now compute the size of this bound. We need to provide
2181 GCC with an upper bound to use but have to deal with the
2182 "superflat" case. There are three ways to do this. If we
2183 can prove that the array can never be superflat, we can
2184 just use the high bound of the index subtype. If we can
2185 prove that the low bound minus one can't overflow, we
2186 can do this as MAX (hb, lb - 1). Otherwise, we have to use
2187 the expression hb >= lb ? hb : lb - 1. */
2190 /* See if the base array type is already flat. If it is, we
2191 are probably compiling an ACVC test, but it will cause the
2192 code below to malfunction if we don't handle it specially. */
2200 /* If gnu_high is now an integer which overflowed, the array
2201 cannot be superflat. */
2208 else
2209 gnu_high
2210 = build_cond_expr
2217 gnat_entity);
2219 /* Also compute the maximum size of the array. Here we
2220 see if any constraint on the index type of the base type
2221 can be used in the case of self-referential bound on
2222 the index type of the subtype. We look for a non-"infinite"
2223 and non-self-referential bound from any type involved and
2224 handle each bound separately. */
2253 gnu_this_max
2257 gnu_base_min)),
2258 size_zero_node);
2264 gnu_max_size
2278 }
2280 /* Then flatten: create the array of arrays. For an array type
2281 used to implement a packed array, get the component type from
2282 the original array type since the representation clauses that
2283 can affect it are on the latter. */
2286 {
2291 /* One of the above calls might have caused us to be elaborated,
2292 so don't blow up if so. */
2294 {
2297 }
2298 }
2299 else
2300 {
2303 /* One of the above calls might have caused us to be elaborated,
2304 so don't blow up if so. */
2306 {
2309 }
2311 /* Try to get a smaller form of the component if needed. */
2321 /* Get and validate any specified Component_Size, but if Packed,
2322 ignore it since the front end will have taken care of it. */
2323 gnu_comp_size
2325 gnat_entity,
2330 /* If the component type is a RECORD_TYPE that has a
2331 self-referential size, use the maximum size. */
2338 {
2339 tree orig_gnu_type;
2340 gnu_type
2346 /* If a padding record was made, declare it now since it
2347 will never be declared otherwise. This is necessary
2348 to ensure that its subtrees are properly marked. */
2352 }
2358 }
2367 {
2372 }
2374 /* If we are at file level and this is a multi-dimensional array, we
2375 need to make a variable corresponding to the stride of the
2376 inner dimensions. */
2378 {
2380 tree gnu_arr_type;
2386 {
2394 /* ??? For now, store the size as a multiple of the
2395 alignment of the element type in bytes so that we
2396 can see the alignment from the tree. */
2398 = build_binary_op
2400 elaborate_expression_1
2410 /* ??? create_type_decl is not invoked on the inner types so
2411 the MULT_EXPR node built above will never be marked. */
2413 }
2414 }
2416 /* If we need to write out a record type giving the names of
2417 the bounds, do it now. */
2419 {
2422 tree gnu_field;
2428 {
2429 tree gnu_type_name
2436 integer_type_node,
2437 gnu_bound_rec_type,
2441 }
2449 add_parallel_type
2451 }
2459 /* If our size depends on a placeholder and the maximum size doesn't
2460 overflow, use it. */
2467 {
2473 }
2475 /* Set our alias set to that of our base type. This gives all
2476 array subtypes the same alias set. */
2478 }
2480 /* If this is a packed type, make this type the same as the packed
2481 array type, but do some adjusting in the type first. */
2484 {
2485 Entity_Id gnat_index;
2486 tree gnu_inner_type;
2488 /* First finish the type we had been making so that we output
2489 debugging information for it */
2490 gnu_type
2493 | (TYPE_QUAL_VOLATILE
2501 /* Save it as our equivalent in case the call below elaborates
2502 this type again. */
2517 /* We need to point the type we just made to our index type so
2518 the actual bounds can be put into a template. */
2524 {
2526 {
2527 /* The TYPE_ACTUAL_BOUNDS field is also used for the modulus.
2528 If it is, we need to make another type. */
2530 {
2531 tree gnu_subtype;
2548 }
2551 }
2557 SET_TYPE_ACTUAL_BOUNDS
2564 SET_TYPE_ACTUAL_BOUNDS
2571 }
2572 }
2574 /* Abort if packed array with no packed array type field set. */
2575 else
2581 /* Create the type for a string literal. */
2582 {
2583 Entity_Id gnat_full_type
2588 tree gnu_string_array_type
2590 tree gnu_string_index_type
2593 tree gnu_lower_bound
2598 tree gnu_upper_bound
2600 gnu_lower_bound,
2602 tree gnu_range_type
2605 tree gnu_index_type
2612 gnu_type
2614 gnu_index_type);
2616 }
2619 /* Record Types and Subtypes
2621 The following fields are defined on record types:
2623 Has_Discriminants True if the record has discriminants
2624 First_Discriminant Points to head of list of discriminants
2625 First_Entity Points to head of list of fields
2626 Is_Tagged_Type True if the record is tagged
2628 Implementation of Ada records and discriminated records:
2630 A record type definition is transformed into the equivalent of a C
2631 struct definition. The fields that are the discriminants which are
2632 found in the Full_Type_Declaration node and the elements of the
2633 Component_List found in the Record_Type_Definition node. The
2634 Component_List can be a recursive structure since each Variant of
2635 the Variant_Part of the Component_List has a Component_List.
2637 Processing of a record type definition comprises starting the list of
2638 field declarations here from the discriminants and the calling the
2639 function components_to_record to add the rest of the fields from the
2640 component list and return the gnu type node. The function
2641 components_to_record will call itself recursively as it traverses
2642 the tree. */
2646 {
2647 gnu_type
2648 = build_complex_type
2649 (get_unpadded_type
2652 (Component_List
2653 (Type_Definition
2657 }
2659 {
2662 Entity_Id gnat_field;
2663 tree gnu_field;
2665 tree gnu_get_parent;
2666 /* Set PACKED in keeping with gnat_to_gnu_field. */
2667 int packed
2679 bool is_extension
2683 /* See if all fields have a rep clause. Stop when we find one
2684 that doesn't. */
2693 /* If this is a record extension, go a level further to find the
2694 record definition. Also, verify we have a Parent_Subtype. */
2696 {
2703 }
2705 /* Make a node for the record. If we are not defining the record,
2706 suppress expanding incomplete types. */
2714 /* If both a size and rep clause was specified, put the size in
2715 the record type now so that it can get the proper mode. */
2719 /* Always set the alignment here so that it can be used to
2720 set the mode, if it is making the alignment stricter. If
2721 it is invalid, it will be checked again below. If this is to
2722 be Atomic, choose a default alignment of a word unless we know
2723 the size and it's smaller. */
2730 /* If a type needs strict alignment, the minimum size will be the
2731 type size instead of the RM size (see validate_size). Cap the
2732 alignment, lest it causes this type size to become too large. */
2735 {
2740 }
2741 else
2744 /* If we have a Parent_Subtype, make a field for the parent. If
2745 this record has rep clauses, force the position to zero. */
2747 {
2749 tree gnu_parent;
2751 /* A major complexity here is that the parent subtype will
2752 reference our discriminants in its Discriminant_Constraint
2753 list. But those must reference the parent component of this
2754 record which is of the parent subtype we have not built yet!
2755 To break the circle we first build a dummy COMPONENT_REF which
2756 represents the "get to the parent" operation and initialize
2757 each of those discriminants to a COMPONENT_REF of the above
2758 dummy parent referencing the corresponding discriminant of the
2759 base type of the parent subtype. */
2763 void_type_node),
2764 NULL_TREE);
2771 save_gnu_tree
2775 gnu_get_parent,
2778 NULL_TREE),
2781 /* Then we build the parent subtype. */
2784 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
2785 initially built. The discriminants must reference the fields
2786 of the parent subtype and not those of its base type for the
2787 placeholder machinery to properly work. */
2793 {
2803 }
2805 /* The "get to the parent" COMPONENT_REF must be given its
2806 proper type... */
2809 /* ...and reference the _parent field of this record. */
2810 gnu_field_list
2818 }
2820 /* Make the fields for the discriminants and put them into the record
2821 unless it's an Unchecked_Union. */
2826 {
2827 /* If this is a record extension and this discriminant
2828 is the renaming of another discriminant, we've already
2829 handled the discriminant above. */
2834 gnu_field
2837 /* Make an expression using a PLACEHOLDER_EXPR from the
2838 FIELD_DECL node just created and link that with the
2839 corresponding GNAT defining identifier. Then add to the
2840 list of fields. */
2849 {
2852 }
2853 }
2855 /* Put the discriminants into the record (backwards), so we can
2856 know the appropriate discriminant to use for the names of the
2857 variants. */
2860 /* Add the listed fields into the record and finish it up. */
2866 /* We used to remove the associations of the discriminants and
2867 _Parent for validity checking, but we may need them if there's
2868 Freeze_Node for a subtype used in this record. */
2872 /* If it is a tagged record force the type to BLKmode to insure
2873 that these objects will always be placed in memory. Do the
2874 same thing for limited record types. */
2878 /* If this is a derived type, we must make the alias set of this type
2879 the same as that of the type we are derived from. We assume here
2880 that the other type is already frozen. */
2886 /* Fill in locations of fields. */
2889 /* If there are any entities in the chain corresponding to
2890 components that we did not elaborate, ensure we elaborate their
2891 types if they are Itypes. */
2899 }
2903 /* If an equivalent type is present, that is what we should use.
2904 Otherwise, fall through to handle this like a record subtype
2905 since it may have constraints. */
2907 {
2911 }
2913 /* ... fall through ... */
2917 /* If Cloned_Subtype is Present it means this record subtype has
2918 identical layout to that type or subtype and we should use
2919 that GCC type for this one. The front end guarantees that
2920 the component list is shared. */
2922 {
2926 }
2928 /* Otherwise, first ensure the base type is elaborated. Then, if we are
2929 changing the type, make a new type with each field having the
2930 type of the field in the new subtype but having the position
2931 computed by transforming every discriminant reference according
2932 to the constraints. We don't see any difference between
2933 private and nonprivate type here since derivations from types should
2934 have been deferred until the completion of the private type. */
2935 else
2936 {
2938 tree gnu_base_type;
2939 tree gnu_orig_type;
2944 /* Get the base type initially for its alignment and sizes. But
2945 if it is a padded type, we do all the other work with the
2946 unpadded type. */
2952 else
2956 {
2959 }
2961 /* When the type has discriminants, and these discriminants
2962 affect the shape of what it built, factor them in.
2964 If we are making a subtype of an Unchecked_Union (must be an
2965 Itype), just return the type.
2967 We can't just use Is_Constrained because private subtypes without
2968 discriminants of full types with discriminants with default
2969 expressions are Is_Constrained but aren't constrained! */
2977 {
2978 Entity_Id gnat_field;
2980 tree gnu_pos_list
2983 BIGGEST_ALIGNMENT);
2984 tree gnu_subst_list
2986 definition);
2987 tree gnu_temp;
2993 /* Set the size, alignment and alias set of the new type to
2994 match that of the old one, doing required substitutions.
2995 We do it this early because we need the size of the new
2996 type below to discard old fields if necessary. */
3022 SET_TYPE_ADA_SIZE
3036 {
3037 tree gnu_old_field
3040 tree gnu_offset
3042 gnu_pos_list));
3045 tree gnu_field_type
3049 unsigned int offset_align
3052 tree gnu_field;
3054 /* If there was a component clause, the field types must be
3055 the same for the type and subtype, so copy the data from
3056 the old field to avoid recomputation here. Also if the
3057 field is justified modular and the optimization in
3058 gnat_to_gnu_field was applied. */
3065 {
3068 }
3070 /* If the old field was packed and of constant size, we
3071 have to get the old size here, as it might differ from
3072 what the Etype conveys and the latter might overlap
3073 onto the following field. Try to arrange the type for
3074 possible better packing along the way. */
3078 {
3083 gnu_field_type
3085 }
3094 /* If the position is now a constant, we can set it as the
3095 position of the field when we make it. Otherwise, we need
3096 to deal with it specially below. */
3098 {
3101 /* Discard old fields that are outside the new type.
3102 This avoids confusing code scanning it to decide
3103 how to pass it to functions on some platforms. */
3110 }
3112 gnu_field
3113 = create_field_decl
3119 {
3128 bitsize_unit_node));
3130 }
3134 SET_DECL_ORIGINAL_FIELD
3145 }
3147 /* Now go through the entities again looking for Itypes that
3148 we have not elaborated but should (e.g., Etypes of fields
3149 that have Original_Components). */
3157 /* Do not finalize it since we're going to modify it below. */
3161 /* Finalize size and mode. */
3168 /* Fill in locations of fields. */
3171 /* We've built a new type, make an XVS type to show what this
3172 is a subtype of. Some debuggers require the XVS type to be
3173 output first, so do it in that order. */
3175 {
3186 integer_type_node,
3187 gnu_subtype_marker,
3193 gnu_subtype_marker);
3194 }
3196 /* Now we can finalize it. */
3198 }
3200 /* Otherwise, go down all the components in the new type and
3201 make them equivalent to those in the base type. */
3202 else
3209 gnat_to_gnu_field_decl
3211 }
3215 /* Use the special descriptor type for dispatch tables if needed,
3216 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3217 Note that we are only required to do so for static tables in
3218 order to be compatible with the C++ ABI, but Ada 2005 allows
3219 to extend library level tagged types at the local level so
3220 we do it in the non-static case as well. */
3223 {
3227 }
3229 /* ... fall through ... */
3232 /* If we are not defining this entity, and we have incomplete
3233 entities being processed above us, make a dummy type and
3234 fill it in later. */
3236 {
3240 gnu_type
3241 = build_pointer_type
3256 }
3258 /* ... fall through ... */
3265 {
3268 bool is_from_limited_with
3272 /* Get the "full view" of this entity. If this is an incomplete
3273 entity from a limited with, treat its non-limited view as the full
3274 view. Otherwise, if this is an incomplete or private type, use the
3275 full view. In the former case, we might point to a private type,
3276 in which case, we need its full view. Also, we want to look at the
3277 actual type used for the representation, so this takes a total of
3278 three steps. */
3279 Entity_Id gnat_desig_full_direct_first
3283 Entity_Id gnat_desig_full_direct
3284 = ((is_from_limited_with
3289 Entity_Id gnat_desig_full
3292 /* This the type actually used to represent the designated type,
3293 either gnat_desig_full or gnat_desig_equiv. */
3294 Entity_Id gnat_desig_rep;
3296 /* Nonzero if this is a pointer to an unconstrained array. */
3299 /* We want to know if we'll be seeing the freeze node for any
3300 incomplete type we may be pointing to. */
3301 bool in_main_unit
3306 /* Nonzero if we make a dummy type here. */
3308 /* Nonzero if the dummy is a fat pointer. */
3316 /* If either the designated type or its full view is an unconstrained
3317 array subtype, replace it with the type it's a subtype of. This
3318 avoids problems with multiple copies of unconstrained array types.
3319 Likewise, if the designated type is a subtype of an incomplete
3320 record type, use the parent type to avoid order of elaboration
3321 issues. This can lose some code efficiency, but there is no
3322 alternative. */
3333 /* Now set the type that actually marks the representation of
3334 the designated type and also flag whether we have a unconstrained
3335 array. */
3337 is_unconstrained_array
3341 /* If we are pointing to an incomplete type whose completion is an
3342 unconstrained array, make a fat pointer type. The two types in our
3343 fields will be pointers to dummy nodes and will be replaced in
3344 update_pointer_to. Similarly, if the type itself is a dummy type or
3345 an unconstrained array. Also make a dummy TYPE_OBJECT_RECORD_TYPE
3346 in case we have any thin pointers to it. */
3357 {
3358 tree gnu_old
3362 tree fields;
3364 /* Show the dummy we get will be a fat pointer. */
3367 /* If the call above got something that has a pointer, that
3368 pointer is our type. This could have happened either
3369 because the type was elaborated or because somebody
3370 else executed the code below. */
3373 {
3394 fields
3396 create_field_decl
3398 gnu_ptr_array,
3401 gnu_ptr_template,
3404 /* Make sure we can place this into a register. */
3409 /* Do not finalize this record type since the types of
3410 its fields are incomplete. */
3418 }
3419 }
3421 /* If we already know what the full type is, use it. */
3426 /* Get the type of the thing we are to point to and build a pointer
3427 to it. If it is a reference to an incomplete or private type with a
3428 full view that is a record, make a dummy type node and get the
3429 actual type later when we have verified it is safe. */
3435 /* Likewise if we are pointing to a record or array and we
3436 are to defer elaborating incomplete types. We do this
3437 since this access type may be the full view of some
3438 private type. Note that the unconstrained array case is
3439 handled above. */
3445 /* If this is a reference from a limited_with type back to our
3446 main unit and there's a Freeze_Node for it, either we have
3447 already processed the declaration and made the dummy type,
3448 in which case we just reuse the latter, or we have not yet,
3449 in which case we make the dummy type and it will be reused
3450 when the declaration is processed. In both cases, the
3451 pointer eventually created below will be automatically
3452 adjusted when the Freeze_Node is processed. Note that the
3453 unconstrained array case is handled above. */
3456 {
3459 }
3461 /* Otherwise handle the case of a pointer to itself. */
3463 {
3464 gnu_type
3468 }
3470 /* If expansion is disabled, the equivalent type of a concurrent
3471 type is absent, so build a dummy pointer type. */
3475 /* Finally, handle the straightforward case where we can just
3476 elaborate our designated type and point to it. */
3477 else
3480 /* It is possible that a call to gnat_to_gnu_type above resolved our
3481 type. If so, just return it. */
3483 {
3486 }
3488 /* If we have a GCC type for the designated type, possibly modify it
3489 if we are pointing only to constant objects and then make a pointer
3490 to it. Don't do this for unconstrained arrays. */
3492 {
3495 {
3496 gnu_desig_type
3497 = build_qualified_type
3501 /* Some extra processing is required if we are building a
3502 pointer to an incomplete type (in the GCC sense). We might
3503 have such a type if we just made a dummy, or directly out
3504 of the call to gnat_to_gnu_type above if we are processing
3505 an access type for a record component designating the
3506 record type itself. */
3508 {
3509 /* We must ensure that the pointer to variant we make will
3510 be processed by update_pointer_to when the initial type
3511 is completed. Pretend we made a dummy and let further
3512 processing act as usual. */
3515 /* We must ensure that update_pointer_to will not retrieve
3516 the dummy variant when building a properly qualified
3517 version of the complete type. We take advantage of the
3518 fact that get_qualified_type is requiring TYPE_NAMEs to
3519 match to influence build_qualified_type and then also
3520 update_pointer_to here. */
3523 }
3524 }
3526 gnu_type
3529 }
3531 /* If we are not defining this object and we made a dummy pointer,
3532 save our current definition, evaluate the actual type, and replace
3533 the tentative type we made with the actual one. If we are to defer
3534 actually looking up the actual type, make an entry in the
3535 deferred list. If this is from a limited with, we have to defer
3536 to the end of the current spec in two cases: first if the
3537 designated type is in the current unit and second if the access
3538 type is. */
3540 {
3541 tree gnu_old_type
3547 gnu_type
3548 = build_pointer_type
3549 (TYPE_OBJECT_RECORD_TYPE
3561 && ! (is_from_limited_with
3562 && (in_main_unit
3567 /* Note that the call to gnat_to_gnu_type here might have
3568 updated gnu_old_type directly, in which case it is not a
3569 dummy type any more when we get into update_pointer_to.
3571 This may happen for instance when the designated type is a
3572 record type, because their elaboration starts with an
3573 initial node from make_dummy_type, which may yield the same
3574 node as the one we got.
3576 Besides, variants of this non-dummy type might have been
3577 created along the way. update_pointer_to is expected to
3578 properly take care of those situations. */
3579 else
3580 {
3585 = (is_from_limited_with
3586 && (in_main_unit
3594 }
3595 }
3596 }
3603 else
3604 {
3605 /* The runtime representation is the equivalent type. */
3608 }
3621 /* We treat this as identical to its base type; any constraint is
3622 meaningful only to the front end.
3624 The designated type must be elaborated as well, if it does
3625 not have its own freeze node. Designated (sub)types created
3626 for constrained components of records with discriminants are
3627 not frozen by the front end and thus not elaborated by gigi,
3628 because their use may appear before the base type is frozen,
3629 and because it is not clear that they are needed anywhere in
3630 Gigi. With the current model, there is no correct place where
3631 they could be elaborated. */
3638 {
3639 /* If we are not defining this entity, and we have incomplete
3640 entities being processed above us, make a dummy type and
3641 elaborate it later. */
3643 {
3646 tree gnu_ptr_type
3647 = build_pointer_type
3654 }
3657 Incomplete_Or_Private_Kind))
3660 }
3665 /* Subprogram Entities
3667 The following access functions are defined for subprograms (functions
3668 or procedures):
3670 First_Formal The first formal parameter.
3671 Is_Imported Indicates that the subprogram has appeared in
3672 an INTERFACE or IMPORT pragma. For now we
3673 assume that the external language is C.
3674 Is_Exported Likewise but for an EXPORT pragma.
3675 Is_Inlined True if the subprogram is to be inlined.
3677 In addition for function subprograms we have:
3679 Etype Return type of the function.
3681 Each parameter is first checked by calling must_pass_by_ref on its
3682 type to determine if it is passed by reference. For parameters which
3683 are copied in, if they are Ada In Out or Out parameters, their return
3684 value becomes part of a record which becomes the return type of the
3685 function (C function - note that this applies only to Ada procedures
3686 so there is no Ada return type). Additional code to store back the
3687 parameters will be generated on the caller side. This transformation
3688 is done here, not in the front-end.
3690 The intended result of the transformation can be seen from the
3691 equivalent source rewritings that follow:
3693 struct temp {int a,b};
3694 procedure P (A,B: In Out ...) is temp P (int A,B)
3695 begin {
3696 .. ..
3697 end P; return {A,B};
3698 }
3700 temp t;
3701 P(X,Y); t = P(X,Y);
3702 X = t.a , Y = t.b;
3704 For subprogram types we need to perform mainly the same conversions to
3705 GCC form that are needed for procedures and function declarations. The
3706 only difference is that at the end, we make a type declaration instead
3707 of a function declaration. */
3712 {
3713 /* The first GCC parameter declaration (a PARM_DECL node). The
3714 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3715 actually is the head of this parameter list. */
3717 /* Likewise for the stub associated with an exported procedure. */
3719 /* The type returned by a function. If the subprogram is a procedure
3720 this type should be void_type_node. */
3722 /* List of fields in return type of procedure with copy-in copy-out
3723 parameters. */
3725 /* Non-null for subprograms containing parameters passed by copy-in
3726 copy-out (Ada In Out or Out parameters not passed by reference),
3727 in which case it is the list of nodes used to specify the values of
3728 the in out/out parameters that are returned as a record upon
3729 procedure return. The TREE_PURPOSE of an element of this list is
3730 a field of the record and the TREE_VALUE is the PARM_DECL
3731 corresponding to that field. This list will be saved in the
3732 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3734 /* If an import pragma asks to map this subprogram to a GCC builtin,
3735 this is the builtin DECL node. */
3737 /* For the stub associated with an exported procedure. */
3740 Entity_Id gnat_param;
3743 bool extern_flag
3746 /* The semantics of "pure" in Ada essentially matches that of "const"
3747 in the back-end. In particular, both properties are orthogonal to
3748 the "nothrow" property if the EH circuitry is explicit in the
3749 internal representation of the back-end. If we are to completely
3750 hide the EH circuitry from it, we need to declare that calls to pure
3751 Ada subprograms that can throw have side effects since they can
3752 trigger an "abnormal" transfer of control flow; thus they can be
3753 neither "const" nor "pure" in the back-end sense. */
3754 bool const_flag
3767 /* A parameter may refer to this type, so defer completion
3768 of any incomplete types. */
3771 /* If the subprogram has an alias, it is probably inherited, so
3772 we can use the original one. If the original "subprogram"
3773 is actually an enumeration literal, it may be the first use
3774 of its type, so we must elaborate that type now. */
3776 {
3783 /* Elaborate any Itypes in the parameters of this entity. */
3791 }
3793 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3794 corresponding DECL node.
3796 We still want the parameter associations to take place because the
3797 proper generation of calls depends on it (a GNAT parameter without
3798 a corresponding GCC tree has a very specific meaning), so we don't
3799 just break here. */
3803 /* ??? What if we don't find the builtin node above ? warn ? err ?
3804 In the current state we neither warn nor err, and calls will just
3805 be handled as for regular subprograms. */
3810 /* If this function returns by reference, make the actual
3811 return type of this function the pointer and mark the decl. */
3813 {
3816 }
3818 /* If the Mechanism is By_Reference, ensure the return type uses
3819 the machine's by-reference mechanism, which may not the same
3820 as above (e.g., it might be by passing a fake parameter). */
3823 {
3826 /* We expect this bit to be reset by gigi shortly, so can avoid a
3827 type node copy here. This actually also prevents troubles with
3828 the generation of debug information for the function, because
3829 we might have issued such info for this type already, and would
3830 be attaching a distinct type node to the function if we made a
3831 copy here. */
3832 }
3834 /* If we are supposed to return an unconstrained array,
3835 actually return a fat pointer and make a note of that. Return
3836 a pointer to an unconstrained record of variable size. */
3838 {
3841 }
3843 /* If the type requires a transient scope, the result is allocated
3844 on the secondary stack, so the result type of the function is
3845 just a pointer. */
3847 {
3850 }
3852 /* If the type is a padded type and the underlying type would not
3853 be passed by reference or this function has a foreign convention,
3854 return the underlying type. */
3862 /* If the return type has a non-constant size, we convert the function
3863 into a procedure and its caller will pass a pointer to an object as
3864 the first parameter when we call the function. This can happen for
3865 an unconstrained type with a maximum size or a constrained type with
3866 a size not known at compile time. */
3869 {
3871 gnu_param_list
3876 }
3878 /* If the return type has a size that overflows, we cannot have
3879 a function that returns that type. This usage doesn't make
3880 sense anyway, so give an error here. */
3884 {
3886 gnat_entity);
3892 }
3894 /* Look at all our parameters and get the type of
3895 each. While doing this, build a copy-out structure if
3896 we need one. */
3898 /* Loop over the parameters and get their associated GCC tree.
3899 While doing this, build a copy-out structure if we need one. */
3903 {
3910 /* Builtins are expanded inline and there is no real call sequence
3911 involved. So the type expected by the underlying expander is
3912 always the type of each argument "as is". */
3915 /* Handle the first parameter of a valued procedure specially. */
3918 /* Otherwise, see if a Mechanism was supplied that forced this
3919 parameter to be passed one way or another. */
3922 ;
3931 {
3935 mech))
3937 else
3939 }
3940 else
3941 {
3944 }
3946 gnu_param
3951 /* We are returned either a PARM_DECL or a type if no parameter
3952 needs to be passed; in either case, adjust the type. */
3955 else
3956 {
3959 }
3962 {
3963 /* If it's an exported subprogram, we build a parameter list
3964 in parallel, in case we need to emit a stub for it. */
3966 {
3967 gnu_stub_param_list
3969 /* Change By_Descriptor parameter to By_Reference for
3970 the internal version of an exported subprogram. */
3972 {
3973 gnu_param
3978 }
3979 else
3981 }
3988 /* If a parameter is a pointer, this function may modify
3989 memory through it and thus shouldn't be considered
3990 a const function. Also, the memory may be modified
3991 between two calls, so they can't be CSE'ed. The latter
3992 case also handles by-ref parameters. */
3996 }
3999 {
4001 {
4006 }
4015 gnu_return_list);
4016 }
4017 }
4019 /* Do not compute record for out parameters if subprogram is
4020 stubbed since structures are incomplete for the back-end. */
4025 /* If we have a CICO list but it has only one entry, we convert
4026 this function into a function that simply returns that one
4027 object. */
4032 prepend_one_attribute_to
4035 gnat_entity);
4037 /* If we are on a target where stack realignment is needed for 'main'
4038 to honor GCC's implicit expectations (stack alignment greater than
4039 what the base ABI guarantees), ensure we do the same for foreign
4040 convention subprograms as they might be used as callbacks from code
4041 breaking such expectations. Note that this applies to task entry
4042 points in particular. */
4045 prepend_one_attribute_to
4048 gnat_entity);
4050 /* The lists have been built in reverse. */
4060 gnu_type
4066 gnu_stub_type
4071 /* A subprogram (something that doesn't return anything) shouldn't
4072 be considered const since there would be no reason for such a
4073 subprogram. Note that procedures with Out (or In Out) parameters
4074 have already been converted into a function with a return type. */
4078 gnu_type
4087 gnu_stub_type
4093 /* If we have a builtin decl for that function, check the signatures
4094 compatibilities. If the signatures are compatible, use the builtin
4095 decl. If they are not, we expect the checker predicate to have
4096 posted the appropriate errors, and just continue with what we have
4097 so far. */
4099 {
4103 {
4107 }
4108 }
4110 /* If there was no specified Interface_Name and the external and
4111 internal names of the subprogram are the same, only use the
4112 internal name to allow disambiguation of nested subprograms. */
4116 /* If we are defining the subprogram and it has an Address clause
4117 we must get the address expression from the saved GCC tree for the
4118 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4119 the address expression here since the front-end has guaranteed
4120 in that case that the elaboration has no effects. If there is
4121 an Address clause and we are not defining the object, just
4122 make it a constant. */
4124 {
4128 gnu_address
4135 /* Convert the type of the object to a reference type that can
4136 alias everything as per 13.3(19). */
4137 gnu_type
4142 gnu_decl
4147 }
4153 else
4154 {
4156 {
4160 }
4166 gnat_entity);
4168 {
4169 tree gnu_stub_decl
4174 gnat_entity);
4176 }
4178 /* This is unrelated to the stub built right above. */
4181 }
4182 }
4193 {
4194 /* Get the "full view" of this entity. If this is an incomplete
4195 entity from a limited with, treat its non-limited view as the
4196 full view. Otherwise, use either the full view or the underlying
4197 full view, whichever is present. This is used in all the tests
4198 below. */
4199 Entity_Id full_view
4207 /* If this is an incomplete type with no full view, it must be a Taft
4208 Amendment type, in which case we return a dummy type. Otherwise,
4209 just get the type from its Etype. */
4211 {
4214 else
4215 {
4219 }
4221 }
4223 /* If we already made a type for the full view, reuse it. */
4225 {
4228 }
4230 /* Otherwise, if we are not defining the type now, get the type
4231 from the full view. But always get the type from the full view
4232 for define on use types, since otherwise we won't see them! */
4238 {
4242 }
4244 /* For incomplete types, make a dummy type entry which will be
4245 replaced later. */
4248 /* Save this type as the full declaration's type so we can do any
4249 needed updates when we see it. */
4255 }
4257 /* Simple class_wide types are always viewed as their root_type
4258 by Gigi unless an Equivalent_Type is specified. */
4270 else
4282 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4283 we've already saved it, so we don't try to. */
4290 }
4292 /* If we had a case where we evaluated another type and it might have
4293 defined this one, handle it here. */
4295 {
4298 }
4300 /* If we are processing a type and there is either no decl for it or
4301 we just made one, do some common processing for the type, such as
4302 handling alignment and possible padding. */
4305 {
4313 /* ??? Don't set the size for a String_Literal since it is either
4314 confirming or we don't handle it properly (if the low bound is
4315 non-constant). */
4321 /* If a size was specified, see if we can make a new type of that size
4322 by rearranging the type, for example from a fat to a thin pointer. */
4324 {
4325 gnu_type
4332 }
4334 /* If the alignment hasn't already been processed and this is
4335 not an unconstrained array, see if an alignment is specified.
4336 If not, we pick a default alignment for atomic objects. */
4338 ;
4340 {
4344 /* Warn on suspiciously large alignments. This should catch
4345 errors about the (alignment,byte)/(size,bit) discrepancy. */
4347 {
4348 tree size;
4350 /* If a size was specified, take it into account. Otherwise
4351 use the RM size for records as the type size has already
4352 been adjusted to the alignment. */
4360 else
4363 /* Consider an alignment as suspicious if the alignment/size
4364 ratio is greater or equal to the byte/bit ratio. */
4369 gnat_entity);
4370 }
4371 }
4382 /* See if we need to pad the type. If we did, and made a record,
4383 the name of the new type may be changed. So get it back for
4384 us when we make the new TYPE_DECL below. */
4391 {
4395 }
4399 /* If we are at global level, GCC will have applied variable_size to
4400 the type, but that won't have done anything. So, if it's not
4401 a constant or self-referential, call elaborate_expression_1 to
4402 make a variable for the size rather than calculating it each time.
4403 Handle both the RM size and the actual size. */
4408 {
4412 {
4419 }
4420 else
4421 {
4428 /* ??? For now, store the size as a multiple of the alignment
4429 in bytes so that we can see the alignment from the tree. */
4431 = build_binary_op
4433 elaborate_expression_1
4444 SET_TYPE_ADA_SIZE
4447 gnat_entity,
4451 }
4452 }
4454 /* If this is a record type or subtype, call elaborate_expression_1 on
4455 any field position. Do this for both global and local types.
4456 Skip any fields that we haven't made trees for to avoid problems with
4457 class wide types. */
4462 {
4465 /* ??? Unfortunately, GCC needs to be able to prove the
4466 alignment of this offset and if it's a variable, it can't.
4467 In GCC 3.4, we'll use DECL_OFFSET_ALIGN in some way, but
4468 right now, we have to put in an explicit multiply and
4469 divide by that value. */
4471 {
4473 = build_binary_op
4475 elaborate_expression_1
4485 /* ??? The context of gnu_field is not necessarily gnu_type so
4486 the MULT_EXPR node built above may not be marked by the call
4487 to create_type_decl below. */
4490 }
4491 }
4495 | (TYPE_QUAL_VOLATILE
4511 else
4513 }
4516 {
4519 /* Back-annotate the Alignment of the type if not already in the
4520 tree. Likewise for sizes. */
4526 {
4527 /* If the size is self-referential, we annotate the maximum
4528 value of that size. */
4537 {
4538 /* In this mode the tag and the parent components are not
4539 generated by the front-end, so the sizes must be adjusted
4540 explicitly now. */
4544 {
4545 size_offset
4549 }
4550 else
4558 }
4559 }
4563 }
4573 /* If we haven't already, associate the ..._DECL node that we just made with
4574 the input GNAT entity node. */
4578 /* If this is an enumeral or floating-point type, we were not able to set
4579 the bounds since they refer to the type. These bounds are always static.
4581 For enumeration types, also write debugging information and declare the
4582 enumeration literal table, if needed. */
4586 {
4589 /* If this is a padded type, we need to use the underlying type. */
4594 /* If this is a floating point type and we haven't set a floating
4595 point type yet, use this in the evaluation of the bounds. */
4605 {
4606 /* Since this has both a typedef and a tag, avoid outputting
4607 the name twice. */
4610 }
4611 }
4613 /* If we deferred processing of incomplete types, re-enable it. If there
4614 were no other disables and we have some to process, do so. */
4616 {
4618 {
4621 /* We are back to level 0 for the deferring of incomplete types.
4622 But processing these incomplete types below may itself require
4623 deferring, so preserve what we have and restart from scratch. */
4627 /* For finalization, however, all types must be complete so we
4628 cannot do the same because deferred incomplete types may end up
4629 referencing each other. Process them all recursively first. */
4630 defer_finalize_level++;
4633 {
4640 }
4642 defer_finalize_level--;
4643 }
4645 /* All the deferred incomplete types have been processed so we can
4646 now proceed with the finalization of the deferred types. */
4648 {
4650 tree t;
4656 }
4657 }
4659 /* If we are not defining this type, see if it's in the incomplete list.
4660 If so, handle that list entry now. */
4662 {
4667 {
4671 }
4672 }
4675 force_global--;
4684 }
4686 /* Similar, but if the returned value is a COMPONENT_REF, return the
4687 FIELD_DECL. */
4689 tree
4691 {
4698 }
4700 /* Wrap up compilation of DECL, a TYPE_DECL, possibly deferring it.
4701 Every TYPE_DECL generated for a type definition must be passed
4702 to this function once everything else has been done for it. */
4704 void
4706 {
4707 /* We need to defer finalizing the type if incomplete types
4708 are being deferred or if they are being processed. */
4711 else
4713 }
4715 /* Same as above but without deferring the compilation. This
4716 function should not be invoked directly on a TYPE_DECL. */
4718 static void
4720 {
4726 /* Now process all the variants. This is needed for STABS. */
4728 {
4733 {
4736 }
4739 }
4740 }
4742 /* Finalize any From_With_Type incomplete types. We do this after processing
4743 our compilation unit and after processing its spec, if this is a body. */
4745 void
4747 {
4753 {
4760 }
4761 }
4763 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
4764 kind of type (such E_Task_Type) that has a different type which Gigi
4765 uses for its representation. If the type does not have a special type
4766 for its representation, return GNAT_ENTITY. If a type is supposed to
4767 exist, but does not, abort unless annotating types, in which case
4768 return Empty. If GNAT_ENTITY is Empty, return Empty. */
4770 Entity_Id
4772 {
4779 {
4805 }
4809 }
4811 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
4812 using MECH as its passing mechanism, to be placed in the parameter
4813 list built for GNAT_SUBPROG. Assume a foreign convention for the
4814 latter if FOREIGN is true. Also set CICO to true if the parameter
4815 must use the copy-in copy-out implementation mechanism.
4817 The returned tree is a PARM_DECL, except for those cases where no
4818 parameter needs to be actually passed to the subprogram; the type
4819 of this "shadow" parameter is then returned instead. */
4821 static tree
4824 {
4829 /* The parameter can be indirectly modified if its address is taken. */
4832 tree gnu_param;
4834 /* Copy-return is used only for the first parameter of a valued procedure.
4835 It's a copy mechanism for which a parameter is never allocated. */
4837 {
4841 }
4843 /* If this is either a foreign function or if the underlying type won't
4844 be passed by reference, strip off possible padding type. */
4847 {
4851 || foreign
4855 }
4857 /* If this is a read-only parameter, make a variant of the type that is
4858 read-only. ??? However, if this is an unconstrained array, that type
4859 can be very complex, so skip it for now. Likewise for any other
4860 self-referential type. */
4868 /* For foreign conventions, pass arrays as pointers to the element type.
4869 First check for unconstrained array and get the underlying array. */
4871 gnu_param_type
4874 /* VMS descriptors are themselves passed by reference. */
4877 gnu_param_type
4880 gnat_subprog));
4882 {
4883 /* Build both a 32-bit and 64-bit descriptor, one of which will be
4884 chosen in fill_vms_descriptor. */
4885 gnu_param_type_alt
4888 gnat_subprog));
4889 gnu_param_type
4892 gnat_subprog));
4893 }
4895 /* Arrays are passed as pointers to element type for foreign conventions. */
4899 {
4900 /* Strip off any multi-dimensional entries, then strip
4901 off the last array to get the component type. */
4915 }
4917 /* Fat pointers are passed as thin pointers for foreign conventions. */
4919 gnu_param_type
4922 /* If we must pass or were requested to pass by reference, do so.
4923 If we were requested to pass by copy, do so.
4924 Otherwise, for foreign conventions, pass In Out or Out parameters
4925 or aggregates by reference. For COBOL and Fortran, pass all
4926 integer and FP types that way too. For Convention Ada, use
4927 the standard Ada default. */
4931 && ((foreign
4933 || (foreign
4938 || (!foreign
4940 {
4943 }
4945 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
4952 /* If this is an Out parameter that isn't passed by reference and isn't
4953 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
4954 it will be a VAR_DECL created when we process the procedure, so just
4955 return its type. For the special parameter of a valued procedure,
4956 never pass it in.
4958 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
4959 Out parameters with discriminants or implicit initial values to be
4960 handled like In Out parameters. These type are normally built as
4961 aggregates, hence passed by reference, except for some packed arrays
4962 which end up encoded in special integer types.
4964 The exception we need to make is then for packed arrays of records
4965 with discriminants or implicit initial values. We have no light/easy
4966 way to check for the latter case, so we merely check for packed arrays
4967 of records. This may lead to useless copy-in operations, but in very
4968 rare cases only, as these would be exceptions in a set of already
4969 exceptional situations. */
4971 && !by_ref
4972 && (by_return
4991 /* Save the alternate descriptor type, if any. */
4995 /* If no Mechanism was specified, indicate what we're using, then
4996 back-annotate it. */
5002 }
5004 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
5006 static bool
5008 {
5015 return
5017 }
5019 /* Return true if the array type specified by GNAT_TYPE and GNU_TYPE has
5020 a non-aliased component in the back-end sense. */
5022 static bool
5024 {
5025 /* If the type below this is a multi-array type, then
5026 this does not have aliased components. */
5035 }
5036 \f
5037 /* Given GNAT_ENTITY, elaborate all expressions that are required to
5038 be elaborated at the point of its definition, but do nothing else. */
5040 void
5042 {
5044 {
5051 {
5055 /* ??? Tests for avoiding static constraint error expression
5056 is needed until the front stops generating bogus conversions
5057 on bounds of real types. */
5066 }
5069 {
5073 /* If this is a record extension, go a level further to find the
5074 record definition. */
5077 }
5087 {
5088 Node_Id gnat_discriminant_expr;
5089 Entity_Id gnat_field;
5092 gnat_discriminant_expr
5097 /* ??? For now, ignore access discriminants. */
5100 gnat_entity,
5102 }
5105 }
5106 }
5107 \f
5108 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
5109 any entities on its entity chain similarly. */
5111 void
5113 {
5114 Entity_Id gnat_sub_entity;
5117 /* If this has an entity list, process all in the list. */
5134 /* Now clear this if it has been defined, but only do so if it isn't
5135 a subprogram or parameter. We could refine this, but it isn't
5136 worth it. If this is statically allocated, it is supposed to
5137 hang around out of cope. */
5140 {
5143 }
5144 }
5145 \f
5146 /* Set the alias set of GNU_NEW_TYPE to be that of GNU_OLD_TYPE. If this
5147 is a multi-dimensional array type, do this recursively. */
5149 static void
5151 {
5152 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
5153 of a one-dimensional array, since the padding has the same alias set
5154 as the field type, but if it's a multi-dimensional array, we need to
5155 see the inner types. */
5161 /* We need to be careful here in case GNU_OLD_TYPE is an unconstrained
5162 array. In that case, it doesn't have the same shape as GNU_NEW_TYPE,
5163 so we need to go down to what does. */
5165 gnu_old_type
5175 }
5176 \f
5177 /* Return a TREE_LIST describing the substitutions needed to reflect
5178 discriminant substitutions from GNAT_SUBTYPE to GNAT_TYPE and add
5179 them to GNU_LIST. If GNAT_TYPE is not specified, use the base type
5180 of GNAT_SUBTYPE. The substitutions can be in any order. TREE_PURPOSE
5181 gives the tree for the discriminant and TREE_VALUES is the replacement
5182 value. They are in the form of operands to substitute_in_expr.
5183 DEFINITION is as in gnat_to_gnu_entity. */
5185 static tree
5188 {
5189 Entity_Id gnat_discrim;
5190 Node_Id gnat_value;
5201 /* Ignore access discriminants. */
5204 elaborate_expression
5208 gnu_list);
5211 }
5212 \f
5213 /* Return true if the size represented by GNU_SIZE can be handled by an
5214 allocation. If STATIC_P is true, consider only what can be done with a
5215 static allocation. */
5217 static bool
5219 {
5220 HOST_WIDE_INT our_size;
5222 /* If this is not a static allocation, the only case we want to forbid
5223 is an overflowing size. That will be converted into a raise a
5224 Storage_Error. */
5229 /* Otherwise, we need to deal with both variable sizes and constant
5230 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
5231 since assemblers may not like very large sizes. */
5237 }
5238 \f
5239 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
5240 NAME, ARGS and ERROR_POINT. */
5242 static void
5245 tree attr_name,
5246 tree attr_args,
5247 Node_Id attr_error_point)
5248 {
5258 }
5260 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
5262 static void
5264 {
5265 Node_Id gnat_temp;
5270 {
5279 {
5281 (gnat_to_gnu
5288 (gnat_to_gnu
5289 (Expression
5292 }
5295 {
5322 }
5325 /* Prepend to the list now. Make a list of the argument we might
5326 have, as GCC expects it. */
5327 prepend_one_attribute_to
5334 }
5335 }
5336 \f
5337 /* Get the unpadded version of a GNAT type. */
5339 tree
5341 {
5348 }
5349 \f
5350 /* Called when we need to protect a variable object using a save_expr. */
5352 tree
5354 {
5361 {
5369 }
5370 else
5372 }
5373 \f
5374 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
5375 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
5376 return the GCC tree to use for that expression. GNU_NAME is the
5377 qualification to use if an external name is appropriate and DEFINITION is
5378 nonzero if this is a definition of GNAT_ENTITY. If NEED_VALUE is nonzero,
5379 we need a result. Otherwise, we are just elaborating this for
5380 side-effects. If NEED_DEBUG is nonzero we need the symbol for debugging
5381 purposes even if it isn't needed for code generation. */
5383 static tree
5387 {
5388 tree gnu_expr;
5390 /* If we already elaborated this expression (e.g., it was involved
5391 in the definition of a private type), use the old value. */
5395 /* If we don't need a value and this is static or a discriminant, we
5396 don't need to do anything. */
5403 /* Otherwise, convert this tree to its GCC equivalent. */
5404 gnu_expr
5408 /* Save the expression in case we try to elaborate this entity again. Since
5409 it's not a DECL, don't check it. Don't save if it's a discriminant. */
5414 }
5416 /* Similar, but take a GNU expression. */
5418 static tree
5422 {
5424 /* Skip any conversions and simple arithmetics to see if the expression
5425 is a read-only variable.
5426 ??? This really should remain read-only, but we have to think about
5427 the typing of the tree here. */
5428 tree gnu_inner_expr
5433 /* In most cases, we won't see a naked FIELD_DECL here because a
5434 discriminant reference will have been replaced with a COMPONENT_REF
5435 when the type is being elaborated. However, there are some cases
5436 involving child types where we will. So convert it to a COMPONENT_REF
5437 here. We have to hope it will be at the highest level of the
5438 expression in these cases. */
5444 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
5445 that is read-only, make a variable that is initialized to contain the
5446 bound when the package containing the definition is elaborated. If
5447 this entity is defined at top level and a bound or discriminant value
5448 isn't a constant or a reference to a discriminant, replace the bound
5449 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
5450 rely here on the fact that an expression cannot contain both the
5451 discriminant and some other variable. */
5459 /* If this is a static expression or contains a discriminant, we don't
5460 need the variable for debugging (and can't elaborate anyway if a
5461 discriminant). */
5467 /* Now create the variable if we need it. */
5469 gnu_decl
5476 /* We only need to use this variable if we are in global context since GCC
5477 can do the right thing in the local case. */
5482 else
5484 }
5485 \f
5486 /* Create a record type that contains a SIZE bytes long field of TYPE with a
5487 starting bit position so that it is aligned to ALIGN bits, and leaving at
5488 least ROOM bytes free before the field. BASE_ALIGN is the alignment the
5489 record is guaranteed to get. */
5491 tree
5494 {
5495 /* We will be crafting a record type with one field at a position set to be
5496 the next multiple of ALIGN past record'address + room bytes. We use a
5497 record placeholder to express record'address. */
5502 tree record_addr_st
5505 /* The diagram below summarizes the shape of what we manipulate:
5507 <--------- pos ---------->
5508 { +------------+-------------+-----------------+
5509 record =>{ |############| ... | field (type) |
5510 { +------------+-------------+-----------------+
5511 |<-- room -->|<- voffset ->|<---- size ----->|
5512 o o
5513 | |
5514 record_addr vblock_addr
5516 Every length is in sizetype bytes there, except "pos" which has to be
5517 set as a bit position in the GCC tree for the record. */
5530 /* Compute VOFFSET and then POS. The next byte position multiple of some
5531 alignment after some address is obtained by "and"ing the alignment minus
5532 1 with the two's complement of the address. */
5538 /* POS = (ROOM + VOFFSET) * BIT_PER_UNIT, in bitsizetype. */
5543 bitsize_unit_node);
5545 /* Craft the GCC record representation. We exceptionally do everything
5546 manually here because 1) our generic circuitry is not quite ready to
5547 handle the complex position/size expressions we are setting up, 2) we
5548 have a strong simplifying factor at hand: we know the maximum possible
5549 value of voffset, and 3) we have to set/reset at least the sizes in
5550 accordance with this maximum value anyway, as we need them to convey
5551 what should be "alloc"ated for this type.
5553 Use -1 as the 'addressable' indication for the field to prevent the
5554 creation of a bitfield. We don't need one, it would have damaging
5555 consequences on the alignment computation, and create_field_decl would
5556 make one without this special argument, for instance because of the
5557 complex position expression. */
5569 bitsize_unit_node),
5579 }
5580 \f
5581 /* Return the result of rounding T up to ALIGN. */
5585 {
5590 }
5592 /* TYPE is a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE that is being used
5593 as the field type of a packed record if IN_RECORD is true, or as the
5594 component type of a packed array if IN_RECORD is false. See if we can
5595 rewrite it either as a type that has a non-BLKmode, which we can pack
5596 tighter in the packed record case, or as a smaller type with BLKmode.
5597 If so, return the new type. If not, return the original type. */
5599 static tree
5601 {
5606 /* No point in doing anything if the size is zero. */
5612 /* Copy the name and flags from the old type to that of the new.
5613 Note that we rely on the pointer equality created here for
5614 TYPE_NAME to look through conversions in various places. */
5621 /* If we are in a record and have a small size, set the alignment to
5622 try for an integral mode. Otherwise set it to try for a smaller
5623 type with BLKmode. */
5625 {
5628 }
5629 else
5630 {
5633 /* Do not try to shrink the size if the RM size is not constant. */
5638 /* Round the RM size up to a unit boundary to get the minimal size
5639 for a BLKmode record. Give up if it's already the size. */
5647 }
5651 /* Now copy the fields, keeping the position and size as we don't want
5652 to change the layout by propagating the packedness downwards. */
5655 {
5666 /* However, for the last field in a not already packed record type
5667 that is of an aggregate type, we need to use the RM_Size in the
5668 packable version of the record type, see finish_record_type. */
5678 else
5687 SET_DECL_ORIGINAL_FIELD
5696 }
5701 /* If this is a padding record, we never want to make the size smaller
5702 than what was specified. For QUAL_UNION_TYPE, also copy the size. */
5705 {
5708 }
5709 else
5710 {
5714 }
5721 /* Try harder to get a packable type if necessary, for example
5722 in case the record itself contains a BLKmode field. */
5727 /* If neither the mode nor the size has shrunk, return the old type. */
5732 }
5733 \f
5734 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
5735 if needed. We have already verified that SIZE and TYPE are large enough.
5737 GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
5738 to issue a warning.
5740 IS_USER_TYPE is true if we must complete the original type.
5742 DEFINITION is true if this type is being defined.
5744 SAME_RM_SIZE is true if the RM_Size of the resulting type is to be set
5745 to SIZE too; otherwise, it's set to the RM_Size of the original type. */
5747 tree
5751 {
5757 /* If TYPE is a padded type, see if it agrees with any size and alignment
5758 we were given. If so, return the original type. Otherwise, strip
5759 off the padding, since we will either be returning the inner type
5760 or repadding it. If no size or alignment is specified, use that of
5761 the original padded type. */
5763 {
5780 }
5782 /* If the size is either not being changed or is being made smaller (which
5783 is not done here (and is only valid for bitfields anyway), show the size
5784 isn't changing. Likewise, clear the alignment if it isn't being
5785 changed. Then return if we aren't doing anything. */
5798 /* If requested, complete the original type and give it a name. */
5805 gnat_entity);
5807 /* We used to modify the record in place in some cases, but that could
5808 generate incorrect debugging information. So make a new record
5809 type and name. */
5827 bitsize_unit_node));
5829 /* If we are changing the alignment and the input type is a record with
5830 BLKmode and a small constant size, try to make a form that has an
5831 integral mode. This might allow the padding record to also have an
5832 integral mode, which will be much more efficient. There is no point
5833 in doing so if a size is specified unless it is also a small constant
5834 size and it is incorrect to do so if we cannot guarantee that the mode
5835 will be naturally aligned since the field must always be addressable.
5837 ??? This might not always be a win when done for a stand-alone object:
5838 since the nominal and the effective type of the object will now have
5839 different modes, a VIEW_CONVERT_EXPR will be required for converting
5840 between them and it might be hard to overcome afterwards, including
5841 at the RTL level when the stand-alone object is accessed as a whole. */
5848 && (!size
5851 {
5856 }
5858 /* Now create the field with the original size. */
5863 /* Do not finalize it until after the auxiliary record is built. */
5866 /* Set the same size for its RM_size if requested; otherwise reuse
5867 the RM_size of the original type. */
5870 /* Unless debugging information isn't being written for the input type,
5871 write a record that shows what we are a subtype of and also make a
5872 variable that indicates our size, if still variable. */
5878 {
5902 }
5906 /* If the size was widened explicitly, maybe give a warning. Take the
5907 original size as the maximum size of the input if there was an
5908 unconstrained record involved and round it up to the specified alignment,
5909 if one was specified. */
5921 {
5934 /* Generate message only for entities that come from source, since
5935 if we have an entity created by expansion, the message will be
5936 generated for some other corresponding source entity. */
5939 gnat_entity,
5946 }
5949 }
5950 \f
5951 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
5952 the value passed against the list of choices. */
5954 tree
5956 {
5957 Node_Id choice;
5958 Node_Id gnat_temp;
5963 {
5965 {
5970 /* There's no good type to use here, so we might as well use
5971 integer_type_node. */
5972 this_test
5986 this_test
5996 /* This represents either a subtype range, an enumeration
5997 literal, or a constant Ekind says which. If an enumeration
5998 literal or constant, fall through to the next case. */
6001 {
6007 this_test
6014 }
6016 /* ... fall through ... */
6022 single);
6031 }
6035 }
6038 }
6039 \f
6040 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
6041 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
6043 static int
6045 {
6046 /* If the field contains an item of variable size, we cannot pack it
6047 because we cannot create temporaries of non-fixed size in case
6048 we need to take the address of the field. See addressable_p and
6049 the notes on the addressability issues for further details. */
6053 /* If the alignment of the record is specified and the field type
6054 is over-aligned, request Storage_Unit alignment for the field. */
6056 {
6059 else
6061 }
6064 }
6066 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
6067 placed in GNU_RECORD_TYPE.
6069 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
6070 record has Component_Alignment of Storage_Unit, -2 if the enclosing
6071 record has a specified alignment.
6073 DEFINITION is true if this field is for a record being defined. */
6075 static tree
6078 {
6082 bool needs_strict_alignment
6086 /* If this field requires strict alignment, we cannot pack it because
6087 it would very likely be under-aligned in the record. */
6090 else
6093 /* If a size is specified, use it. Otherwise, if the record type is packed,
6094 use the official RM size. See "Handling of Type'Size Values" in Einfo
6095 for further details. */
6102 else
6105 /* If we have a specified size that's smaller than that of the field type,
6106 or a position is specified, and the field type is also a record that's
6107 BLKmode, see if we can get either an integral mode form of the type or
6108 a smaller BLKmode form. If we can, show a size was specified for the
6109 field if there wasn't one already, so we know to make this a bitfield
6110 and avoid making things wider.
6112 Doing this is first useful if the record is packed because we may then
6113 place the field at a non-byte-aligned position and so achieve tighter
6114 packing.
6116 This is in addition *required* if the field shares a byte with another
6117 field and the front-end lets the back-end handle the references, because
6118 GCC does not handle BLKmode bitfields properly.
6120 We avoid the transformation if it is not required or potentially useful,
6121 as it might entail an increase of the field's alignment and have ripple
6122 effects on the outer record type. A typical case is a field known to be
6123 byte aligned and not to share a byte with another field.
6125 Besides, we don't even look the possibility of a transformation in cases
6126 known to be in error already, for instance when an invalid size results
6127 from a component clause. */
6133 || (gnu_size
6136 {
6137 /* See what the alternate type and size would be. */
6140 bool has_byte_aligned_clause
6145 /* Compute whether we should avoid the substitution. */
6146 bool reject
6147 /* There is no point substituting if there is no change... */
6149 /* ... nor when the field is known to be byte aligned and not to
6150 share a byte with another field. */
6151 || (has_byte_aligned_clause
6153 /* The size of an aliased field must be an exact multiple of the
6154 type's alignment, which the substitution might increase. Reject
6155 substitutions that would so invalidate a component clause when the
6156 specified position is byte aligned, as the change would have no
6157 real benefit from the packing standpoint anyway. */
6159 && has_byte_aligned_clause
6162 /* Substitute unless told otherwise. */
6164 {
6169 }
6170 }
6172 /* If we are packing the record and the field is BLKmode, round the
6173 size up to a byte boundary. */
6178 {
6183 /* Ensure the position does not overlap with the parent subtype,
6184 if there is one. */
6186 {
6187 tree gnu_parent
6193 {
6194 post_error_ne_tree
6198 }
6199 }
6201 /* If this field needs strict alignment, ensure the record is
6202 sufficiently aligned and that that position and size are
6203 consistent with the alignment. */
6205 {
6211 {
6213 post_error_ne_tree
6219 post_error_ne_tree
6225 post_error_ne_tree
6231 }
6236 {
6238 post_error_ne_num
6244 post_error_ne_num
6250 post_error_ne_num
6255 else
6259 }
6260 }
6264 }
6266 /* If the record has rep clauses and this is the tag field, make a rep
6267 clause for it as well. */
6270 {
6273 }
6275 else
6278 /* We need to make the size the maximum for the type if it is
6279 self-referential and an unconstrained type. In that case, we can't
6280 pack the field since we can't make a copy to align it. */
6282 && !gnu_size
6285 {
6288 }
6290 /* If a size is specified, adjust the field's type to it. */
6292 {
6293 /* If the field's type is justified modular, we would need to remove
6294 the wrapper to (better) meet the layout requirements. However we
6295 can do so only if the field is not aliased to preserve the unique
6296 layout and if the prescribed size is not greater than that of the
6297 packed array to preserve the justification. */
6305 gnu_field_type
6310 }
6312 /* Otherwise (or if there was an error), don't specify a position. */
6313 else
6319 /* Now create the decl for the field. */
6331 }
6332 \f
6333 /* Return true if TYPE is a type with variable size, a padding type with a
6334 field of variable size or is a record that has a field such a field. */
6336 static bool
6338 {
6339 tree field;
6359 }
6360 \f
6361 /* qsort comparer for the bit positions of two record components. */
6363 static int
6365 {
6368 const int ret
6372 }
6374 /* Return a GCC tree for a record type given a GNAT Component_List and a chain
6375 of GCC trees for fields that are in the record and have already been
6376 processed. When called from gnat_to_gnu_entity during the processing of a
6377 record type definition, the GCC nodes for the discriminants will be on
6378 the chain. The other calls to this function are recursive calls from
6379 itself for the Component_List of a variant and the chain is empty.
6381 PACKED is 1 if this is for a packed record, -1 if this is for a record
6382 with Component_Alignment of Storage_Unit, -2 if this is for a record
6383 with a specified alignment.
6385 DEFINITION is true if we are defining this record.
6387 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
6388 with a rep clause is to be added. If it is nonzero, that is all that
6389 should be done with such fields.
6391 CANCEL_ALIGNMENT, if true, means the alignment should be zeroed before
6392 laying out the record. This means the alignment only serves to force fields
6393 to be bitfields, but not require the record to be that aligned. This is
6394 used for variants.
6396 ALL_REP, if true, means a rep clause was found for all the fields. This
6397 simplifies the logic since we know we're not in the mixed case.
6399 DO_NOT_FINALIZE, if true, means that the record type is expected to be
6400 modified afterwards so it will not be sent to the back-end for finalization.
6402 UNCHECKED_UNION, if true, means that we are building a type for a record
6403 with a Pragma Unchecked_Union.
6405 The processing of the component list fills in the chain with all of the
6406 fields of the record and then the record type is finished. */
6408 static void
6413 {
6414 Node_Id component_decl;
6415 Entity_Id gnat_field;
6416 Node_Id variant_part;
6422 /* For each variable within each component declaration create a GCC field
6423 and add it to the list, skipping any pragmas in the list. */
6428 {
6433 else
6434 {
6438 /* If this is the _Tag field, put it before any discriminants,
6439 instead of after them as is the case for all other fields.
6440 Ignore field of void type if only annotating. */
6443 else
6444 {
6447 }
6448 }
6451 }
6453 /* At the end of the component list there may be a variant part. */
6456 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
6457 mutually exclusive and should go in the same memory. To do this we need
6458 to treat each variant as a record whose elements are created from the
6459 component list for the variant. So here we create the records from the
6460 lists for the variants and put them all into the QUAL_UNION_TYPE.
6461 If this is an Unchecked_Union, we make a UNION_TYPE instead or
6462 use GNU_RECORD_TYPE if there are no fields so far. */
6464 {
6466 Node_Id variant;
6468 tree gnu_var_name
6472 tree gnu_union_type;
6473 tree gnu_union_name;
6474 tree gnu_union_field;
6483 /* Reuse an enclosing union if all fields are in the variant part
6484 and there is no representation clause on the record, to match
6485 the layout of C unions. There is an associated check below. */
6490 else
6491 {
6492 gnu_union_type
6498 }
6503 {
6505 tree gnu_inner_name;
6506 tree gnu_qual;
6514 /* Set the alignment of the inner type in case we need to make
6515 inner objects into bitfields, but then clear it out
6516 so the record actually gets only the alignment required. */
6520 /* Similarly, if the outer record has a size specified and all fields
6521 have record rep clauses, we can propagate the size into the
6522 variant part. */
6524 {
6528 }
6530 /* Create the record type for the variant. Note that we defer
6531 finalizing it until after we are sure to actually use it. */
6542 /* If this is an Unchecked_Union and we have exactly one field,
6543 use this field directly to match the layout of C unions. */
6548 else
6549 {
6550 /* Deal with packedness like in gnat_to_gnu_field. */
6551 int field_packed
6554 /* Finalize the record type now. We used to throw away
6555 empty records but we no longer do that because we need
6556 them to generate complete debug info for the variant;
6557 otherwise, the union type definition will be lacking
6558 the fields associated with these empty variants. */
6563 (all_rep_and_size
6566 (all_rep_and_size
6574 }
6578 }
6580 /* Only make the QUAL_UNION_TYPE if there are any non-empty variants. */
6582 {
6586 {
6590 }
6595 /* If GNU_UNION_TYPE is our record type, it means we must have an
6596 Unchecked_Union with no fields. Verify that and, if so, just
6597 return. */
6599 {
6601 && !gnu_field_list
6604 }
6606 /* Deal with packedness like in gnat_to_gnu_field. */
6607 union_field_packed
6610 gnu_union_field
6612 union_field_packed,
6619 }
6620 }
6622 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
6623 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do this
6624 in a separate pass since we want to handle the discriminants but can't
6625 play with them until we've used them in debugging data above.
6627 ??? Note: if we then reorder them, debugging information will be wrong,
6628 but there's nothing that can be done about this at the moment. */
6630 {
6632 {
6637 else
6643 }
6644 else
6645 {
6648 }
6649 }
6651 /* If we have any items in our rep'ed field list, it is not the case that all
6652 the fields in the record have rep clauses, and P_REP_LIST is nonzero,
6653 set it and ignore the items. */
6657 {
6658 /* Otherwise, sort the fields by bit position and put them into their
6659 own record if we have any fields without rep clauses. */
6660 tree gnu_rep_type
6672 /* Put the fields in the list in order of increasing position, which
6673 means we start from the end. */
6676 {
6680 }
6683 {
6689 }
6690 else
6691 {
6694 }
6695 }
6702 }
6703 \f
6704 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
6705 placed into an Esize, Component_Bit_Offset, or Component_Size value
6706 in the GNAT tree. */
6708 static Uint
6710 {
6712 TCode tcode;
6718 /* See if we've already saved the value for this node. */
6720 {
6731 }
6733 /* If we do not return inside this switch, TCODE will be set to the
6734 code to use for a Create_Node operand and LEN (set above) will be
6735 the number of recursive calls for us to make. */
6738 {
6743 /* This may have come from a conversion from some smaller type,
6744 so ensure this is in bitsizetype. */
6747 /* For negative values, use NEGATE_EXPR of the supplied value. */
6749 {
6750 /* The ridiculous code below is to handle the case of the largest
6751 negative integer. */
6754 tree temp;
6757 {
6758 negative_size
6761 bitsize_one_node));
6763 }
6770 }
6777 /* This peculiar test is to make sure that the size fits in an int
6778 on machines where HOST_WIDE_INT is not "int". */
6781 else
6785 /* The only case we handle here is a simple discriminant reference. */
6793 else
6799 /* Now just list the operations we handle. */
6831 }
6833 /* Now get each of the operands that's relevant for this code. If any
6834 cannot be expressed as a repinfo node, say we can't. */
6839 {
6843 }
6847 /* Save the result in the cache. */
6849 {
6853 }
6856 }
6858 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding
6859 GCC type, set Component_Bit_Offset and Esize to the position and size
6860 used by Gigi. */
6862 static void
6864 {
6865 tree gnu_list;
6866 tree gnu_entry;
6867 Entity_Id gnat_field;
6869 /* We operate by first making a list of all fields and their positions
6870 (we can get the sizes easily at any time) by a recursive call
6871 and then update all the sizes into the tree. */
6874 BIGGEST_ALIGNMENT);
6881 {
6885 gnu_list);
6888 {
6890 {
6891 /* In this mode the tag and parent components have not been
6892 generated, so we add the appropriate offset to each
6893 component. For a component appearing in the current
6894 extension, the offset is the size of the parent. */
6897 parent_offset
6899 bitsizetype);
6900 else
6902 }
6904 Set_Component_Bit_Offset
6906 annotate_value
6911 parent_offset)));
6915 }
6918 {
6919 /* If there is no gnu_entry, this is an inherited component whose
6920 position is the same as in the parent type. */
6921 Set_Component_Bit_Offset
6926 }
6927 }
6928 }
6930 /* Scan all fields in GNU_TYPE and build entries where TREE_PURPOSE is the
6931 FIELD_DECL and TREE_VALUE a TREE_LIST with TREE_PURPOSE being the byte
6932 position and TREE_VALUE being a TREE_LIST with TREE_PURPOSE the value to be
6933 placed into DECL_OFFSET_ALIGN and TREE_VALUE the bit position. GNU_POS is
6934 to be added to the position, GNU_BITPOS to the bit position, OFFSET_ALIGN is
6935 the present value of DECL_OFFSET_ALIGN and GNU_LIST is a list of the entries
6936 so far. */
6938 static tree
6941 {
6942 tree gnu_field;
6947 {
6952 unsigned int our_offset_align
6955 gnu_result
6960 NULL_TREE),
6961 gnu_result);
6964 gnu_result
6967 our_offset_align);
6968 }
6971 }
6972 \f
6973 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
6974 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
6975 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
6976 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
6977 for the size of a field. COMPONENT_P is true if we are being called
6978 to process the Component_Size of GNAT_OBJECT. This is used for error
6979 message handling and to indicate to use the object size of GNU_TYPE.
6980 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
6981 it means that a size of zero should be treated as an unspecified size. */
6983 static tree
6986 {
6987 Node_Id gnat_error_node;
6991 /* If a type needs strict alignment, a component of this type in
6992 a packed record cannot be packed and thus uses the type size. */
6995 else
6998 /* Find the node to use for errors. */
7005 else
7008 /* Return 0 if no size was specified, either because Esize was not Present or
7009 the specified size was zero. */
7013 /* Get the size as a tree. Give an error if a size was specified, but cannot
7014 be represented as in sizetype. */
7017 {
7022 }
7024 /* Ignore a negative size since that corresponds to our back-annotation.
7025 Also ignore a zero size unless a size clause exists. */
7029 /* The size of objects is always a multiple of a byte. */
7032 {
7036 else
7040 }
7042 /* If this is an integral type or a packed array type, the front-end has
7043 verified the size, so we need not do it here (which would entail
7044 checking against the bounds). However, if this is an aliased object, it
7045 may not be smaller than the type of the object. */
7050 /* If the object is a record that contains a template, add the size of
7051 the template to the specified size. */
7056 /* Modify the size of the type to be that of the maximum size if it has a
7057 discriminant. */
7061 /* If this is an access type or a fat pointer, the minimum size is that given
7062 by the smallest integral mode that's valid for pointers. */
7064 {
7070 ;
7073 }
7075 /* If the size of the object is a constant, the new size must not be
7076 smaller. */
7080 {
7082 post_error_ne_tree
7085 else
7092 post_error_ne_tree_2
7102 }
7105 }
7106 \f
7107 /* Similarly, but both validate and process a value of RM_Size. This
7108 routine is only called for types. */
7110 static void
7112 {
7113 /* Only give an error if a Value_Size clause was explicitly given.
7114 Otherwise, we'd be duplicating an error on the Size clause. */
7115 Node_Id gnat_attr_node
7118 tree size;
7120 /* Get the size as a tree. Do nothing if none was specified, either
7121 because RM_Size was not Present or if the specified size was zero.
7122 Give an error if a size was specified, but cannot be represented as
7123 in sizetype. */
7129 {
7132 gnat_entity);
7135 }
7137 /* Ignore a negative size since that corresponds to our back-annotation.
7138 Also ignore a zero size unless a size clause exists, a Value_Size
7139 clause exists, or this is an integer type, in which case the
7140 front end will have always set it. */
7147 /* If the old size is self-referential, get the maximum size. */
7151 /* If the size of the object is a constant, the new size must not be
7152 smaller (the front end checks this for scalar types). */
7157 {
7159 post_error_ne_tree
7164 }
7166 /* Otherwise, set the RM_Size. */
7178 }
7179 \f
7180 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
7181 If TYPE is the best type, return it. Otherwise, make a new type. We
7182 only support new integral and pointer types. FOR_BIASED is nonzero if
7183 we are making a biased type. */
7185 static tree
7187 {
7190 tree new_type;
7192 /* If size indicates an error, just return TYPE to avoid propagating
7193 the error. Likewise if it's too large to represent. */
7200 {
7207 /* Only do something if the type is not a packed array type and
7208 doesn't already have the proper size. */
7218 else
7225 /* Propagate the name to avoid creating a fake subrange type. */
7227 {
7230 else
7232 }
7238 /* Do something if this is a fat pointer, in which case we
7239 may need to return the thin pointer. */
7241 {
7245 return
7246 build_pointer_type_for_mode
7249 }
7253 /* Only do something if this is a thin pointer, in which case we
7254 may need to return the fat pointer. */
7256 return
7262 }
7265 }
7266 \f
7267 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
7268 a type or object whose present alignment is ALIGN. If this alignment is
7269 valid, return it. Otherwise, give an error and return ALIGN. */
7271 static unsigned int
7273 {
7276 Node_Id gnat_error_node;
7278 /* Don't worry about checking alignment if alignment was not specified
7279 by the source program and we already posted an error for this entity. */
7283 /* Post the error on the alignment clause if any. */
7286 else
7289 /* Within GCC, an alignment is an integer, so we must make sure a value is
7290 specified that fits in that range. Also, there is an upper bound to
7291 alignments we can support/allow. */
7302 else
7303 {
7307 }
7310 }
7312 /* Return the smallest alignment not less than SIZE. */
7314 static unsigned int
7316 {
7318 }
7319 \f
7320 /* Verify that OBJECT, a type or decl, is something we can implement
7321 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
7322 if we require atomic components. */
7324 static void
7326 {
7328 Node_Id gnat_node;
7331 tree size;
7333 /* There are three case of what OBJECT can be. It can be a type, in which
7334 case we take the size, alignment and mode from the type. It can be a
7335 declaration that was indirect, in which case the relevant values are
7336 that of the type being pointed to, or it can be a normal declaration,
7337 in which case the values are of the decl. The code below assumes that
7338 OBJECT is either a type or a decl. */
7340 {
7344 }
7346 {
7350 }
7351 else
7352 {
7356 }
7358 /* Consider all floating-point types atomic and any types that that are
7359 represented by integers no wider than a machine word. */
7366 /* For the moment, also allow anything that has an alignment equal
7367 to its size and which is smaller than a word. */
7375 {
7384 }
7389 else
7392 }
7393 \f
7394 /* Check if FTYPE1 and FTYPE2, two potentially different function type nodes,
7395 have compatible signatures so that a call using one type may be safely
7396 issued if the actual target function type is the other. Return 1 if it is
7397 the case, 0 otherwise, and post errors on the incompatibilities.
7399 This is used when an Ada subprogram is mapped onto a GCC builtin, to ensure
7400 that calls to the subprogram will have arguments suitable for the later
7401 underlying builtin expansion. */
7403 static int
7405 {
7406 /* As of now, we only perform very trivial tests and consider it's the
7407 programmer's responsibility to ensure the type correctness in the Ada
7408 declaration, as in the regular Import cases.
7410 Mismatches typically result in either error messages from the builtin
7411 expander, internal compiler errors, or in a real call sequence. This
7412 should be refined to issue diagnostics helping error detection and
7413 correction. */
7415 /* Almost fake test, ensuring a use of each argument. */
7420 }
7421 \f
7422 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new
7423 type with all size expressions that contain F updated by replacing F
7424 with R. If F is NULL_TREE, always make a new RECORD_TYPE, even if
7425 nothing has changed. */
7427 tree
7429 {
7431 tree tem;
7434 {
7440 {
7449 SET_TYPE_INDEX_TYPE
7452 }
7459 {
7473 }
7487 /* Don't know how to do these yet. */
7491 {
7506 /* If we had bounded the sizes of T by a constant, bound the sizes of
7507 NEW by the same constant. */
7517 }
7522 {
7523 tree field;
7524 bool changed_field
7531 /* Start out with no fields, make new fields, and chain them
7532 in. If we haven't actually changed the type of any field,
7533 discard everything we've done and return the old type. */
7539 {
7550 /* If this is an internal field and the type of this field is
7551 a UNION_TYPE or RECORD_TYPE with no elements, ignore it. If
7552 the type just has one element, treat that as the field.
7553 But don't do this if we are processing a QUAL_UNION_TYPE. */
7558 {
7563 {
7564 tree next_new_field
7567 /* Make sure omitting the union doesn't change
7568 the layout. */
7571 }
7572 }
7579 /* If the size of the old field was set at a constant,
7580 propagate the size in case the type's size was variable.
7581 (This occurs in the case of a variant or discriminated
7582 record with a default size used as a field of another
7583 record.) */
7592 {
7598 /* Do the substitution inside the qualifier and if we find
7599 that this field will not be present, omit it. */
7604 }
7608 else
7613 /* If this is a qualified type and this field will always be
7614 present, we are done. */
7618 }
7620 /* If this used to be a qualified union type, but we now know what
7621 field will be present, make this a normal union. */
7632 /* If the size was originally a constant use it. */
7635 {
7639 }
7642 }
7646 }
7647 }
7648 \f
7649 /* Return the "RM size" of GNU_TYPE. This is the actual number of bits
7650 needed to represent the object. */
7652 tree
7654 {
7655 /* For integer types, this is the precision. For record types, we store
7656 the size explicitly. For other types, this is just the size. */
7662 /* Return the rm_size of the actual data plus the size of the template. */
7663 return
7673 else
7675 }
7676 \f
7677 /* Return an identifier representing the external name to be used for
7678 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
7679 and the specified suffix. */
7681 tree
7683 {
7692 /* A variable using the Stdcall convention (meaning we are running
7693 on a Windows box) live in a DLL. Here we adjust its name to use
7694 the jump-table, the _imp__NAME contains the address for the NAME
7695 variable. */
7698 {
7705 }
7708 }
7710 /* Return the name to be used for GNAT_ENTITY. If a type, create a
7711 fully-qualified name, possibly with type information encoding.
7712 Otherwise, return the name. */
7714 tree
7716 {
7719 }
7721 /* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
7722 string, return a new IDENTIFIER_NODE that is the concatenation of
7723 the name in GNU_ID and SUFFIX. */
7725 tree
7727 {
7735 }