| blob | f7f4a0d1b61b58b9893cb6634abe1100c0908afa |
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, get its full
371 declaration. */
373 {
378 }
380 /* If we have an external constant that we are not defining, get the
381 expression that is was defined to represent. We may throw that
382 expression away later if it is not a constant. Do not retrieve the
383 expression if it is an aggregate or allocator, because in complex
384 instantiation contexts it may not be expanded */
394 /* Ignore deferred constant definitions; they are processed fully in the
395 front-end. For deferred constant references get the full definition.
396 On the other hand, constants that are renamings are handled like
397 variable renamings. If No_Initialization is set, this is not a
398 deferred constant but a constant whose value is built manually. */
402 {
406 }
409 {
414 }
419 /* We used to special case VMS exceptions here to directly map them to
420 their associated condition code. Since this code had to be masked
421 dynamically to strip off the severity bits, this caused trouble in
422 the GCC/ZCX case because the "type" pointers we store in the tables
423 have to be static. We now don't special case here anymore, and let
424 the regular processing take place, which leaves us with a regular
425 exception data object for VMS exceptions too. The condition code
426 mapping is taken care of by the front end and the bitmasking by the
427 runtime library. */
432 {
433 /* The GNAT record where the component was defined. */
436 /* If the variable is an inherited record component (in the case of
437 extended record types), just return the inherited entity, which
438 must be a FIELD_DECL. Likewise for discriminants.
439 For discriminants of untagged records which have explicit
440 stored discriminants, return the entity for the corresponding
441 stored discriminant. Also use Original_Record_Component
442 if the record has a private extension. */
446 {
447 gnu_decl
452 }
454 /* If the enclosing record has explicit stored discriminants,
455 then it is an untagged record. If the Corresponding_Discriminant
456 is not empty then this must be a renamed discriminant and its
457 Original_Record_Component must point to the corresponding explicit
458 stored discriminant (i.e., we should have taken the previous
459 branch). */
463 {
464 /* A tagged record has no explicit stored discriminants. */
468 gnu_decl
473 }
477 {
482 }
484 /* If the enclosing record has explicit stored discriminants,
485 then it is an untagged record. If the Corresponding_Discriminant
486 is not empty then this must be a renamed discriminant and its
487 Original_Record_Component must point to the corresponding explicit
488 stored discriminant (i.e., we should have taken the first
489 branch). */
496 /* Otherwise, if we are not defining this and we have no GCC type
497 for the containing record, make one for it. Then we should
498 have made our own equivalent. */
500 {
501 /* ??? If this is in a record whose scope is a protected
502 type and we have an Original_Record_Component, use it.
503 This is a workaround for major problems in protected type
504 handling. */
511 {
512 gnu_decl
518 }
524 }
526 else
527 /* Here we have no GCC type and this is a reference rather than a
528 definition. This should never happen. Most likely the cause is a
529 reference before declaration in the gnat tree for gnat_entity. */
531 }
537 /* Simple variables, loop variables, Out parameters, and exceptions. */
538 object:
539 {
541 bool const_flag
553 tree gnu_object_size;
556 {
560 else
562 }
564 /* Get the type after elaborating the renamed object. */
567 /* For a debug renaming declaration, build a pure debug entity. */
569 {
570 rtx addr;
572 /* The (MEM (CONST (0))) pattern is prescribed by STABS. */
575 else
580 }
582 /* If this is a loop variable, its type should be the base type.
583 This is because the code for processing a loop determines whether
584 a normal loop end test can be done by comparing the bounds of the
585 loop against those of the base type, which is presumed to be the
586 size used for computation. But this is not correct when the size
587 of the subtype is smaller than the type. */
591 /* Reject non-renamed objects whose types are unconstrained arrays or
592 any object whose type is a dummy type or VOID_TYPE. */
598 {
601 force_global--;
603 }
605 /* If an alignment is specified, use it if valid. Note that
606 exceptions are objects but don't have alignments. We must do this
607 before we validate the size, since the alignment can affect the
608 size. */
610 {
616 }
618 /* If we are defining the object, see if it has a Size value and
619 validate it if so. If we are not defining the object and a Size
620 clause applies, simply retrieve the value. We don't want to ignore
621 the clause and it is expected to have been validated already. Then
622 get the new type, if any. */
631 {
632 gnu_type
638 }
640 /* If this object has self-referential size, it must be a record with
641 a default value. We are supposed to allocate an object of the
642 maximum size in this case unless it is a constant with an
643 initializing expression, in which case we can get the size from
644 that. Note that the resulting size may still be a variable, so
645 this may end up with an indirect allocation. */
648 {
650 {
653 {
654 /* If the initializing expression is itself a constant,
655 despite having a nominal type with self-referential
656 size, we can get the size directly from it. */
659 == RECORD_TYPE
660 && TYPE_IS_PADDING_P
664 || DECL_READONLY_ONCE_ELAB
667 else
668 gnu_size
670 }
671 else
673 }
674 /* We may have no GNU_EXPR because No_Initialization is
675 set even though there's an Expression. */
680 gnu_size
682 (Etype
684 else
685 {
688 }
689 }
691 /* If the size is zero bytes, make it one byte since some linkers have
692 trouble with zero-sized objects. If the object will have a
693 template, that will make it nonzero so don't bother. Also avoid
694 doing that for an object renaming or an object with an address
695 clause, as we would lose useful information on the view size
696 (e.g. for null array slices) and we are not allocating the object
697 here anyway. */
710 /* If this is an object with no specified size and alignment, and
711 if either it is atomic or we are not optimizing alignment for
712 space and it is composite and not an exception, an Out parameter
713 or a reference to another object, and the size of its type is a
714 constant, set the alignment to the smallest one which is not
715 smaller than the size, with an appropriate cap. */
723 && !imported_p
727 {
728 /* No point in jumping through all the hoops needed in order
729 to support BIGGEST_ALIGNMENT if we don't really have to. */
731 ? BIGGEST_ALIGNMENT
737 else
740 /* But make sure not to under-align the object. */
744 /* And honor the minimum valid atomic alignment, if any. */
745 #ifdef MINIMUM_ATOMIC_ALIGNMENT
748 #endif
749 }
751 /* If the object is set to have atomic components, find the component
752 type and validate it.
754 ??? Note that we ignore Has_Volatile_Components on objects; it's
755 not at all clear what to do in that case. */
758 {
767 }
769 /* Now check if the type of the object allows atomic access. Note
770 that we must test the type, even if this object has size and
771 alignment to allow such access, because we will be going
772 inside the padded record to assign to the object. We could fix
773 this by always copying via an intermediate value, but it's not
774 clear it's worth the effort. */
778 /* If this is an aliased object with an unconstrained nominal subtype,
779 make a type that includes the template. */
783 {
784 tree gnu_fat
787 gnu_type
791 }
793 #ifdef MINIMUM_ATOMIC_ALIGNMENT
794 /* If the size is a constant and no alignment is specified, force
795 the alignment to be the minimum valid atomic alignment. The
796 restriction on constant size avoids problems with variable-size
797 temporaries; if the size is variable, there's no issue with
798 atomic access. Also don't do this for a constant, since it isn't
799 necessary and can interfere with constant replacement. Finally,
800 do not do it for Out parameters since that creates an
801 size inconsistency with In parameters. */
810 #endif
812 /* Make a new type with the desired size and alignment, if needed.
813 But do not take into account alignment promotions to compute the
814 size of the object. */
821 /* Make a volatile version of this object's type if we are to make
822 the object volatile. We also interpret 13.3(19) conservatively
823 and disallow any optimizations for an object covered by it. */
826 /* Exclude exported constants created by the compiler,
827 which should boil down to static dispatch tables and
828 make it possible to put them in read-only memory. */
837 /* If this is a renaming, avoid as much as possible to create a new
838 object. However, in several cases, creating it is required.
839 This processing needs to be applied to the raw expression so
840 as to make it more likely to rename the underlying object. */
842 {
845 /* If the renamed object had padding, strip off the reference
846 to the inner object and reset our type. */
849 == RECORD_TYPE
851 /* Strip useless conversions around the object. */
853 {
856 }
858 /* Case 1: If this is a constant renaming stemming from a function
859 call, treat it as a normal object whose initial value is what
860 is being renamed. RM 3.3 says that the result of evaluating a
861 function call is a constant object. As a consequence, it can
862 be the inner object of a constant renaming. In this case, the
863 renaming must be fully instantiated, i.e. it cannot be a mere
864 reference to (part of) an existing object. */
866 {
872 }
874 /* Otherwise, see if we can proceed with a stabilized version of
875 the renamed entity or if we need to make a new object. */
877 {
881 /* Case 2: If the renaming entity need not be materialized and
882 the renamed expression is something we can stabilize, use
883 that for the renaming. At the global level, we can only do
884 this if we know no SAVE_EXPRs need be made, because the
885 expression we return might be used in arbitrary conditional
886 branches so we must force the SAVE_EXPRs evaluation
887 immediately and this requires a function context. */
892 {
893 maybe_stable_expr
897 {
899 /* ??? No DECL_EXPR is created so we need to mark
900 the expression manually lest it is shared. */
906 }
908 /* The stabilization failed. Keep maybe_stable_expr
909 untouched here to let the pointer case below know
910 about that failure. */
911 }
913 /* Case 3: If this is a constant renaming and creating a
914 new object is allowed and cheap, treat it as a normal
915 object whose initial value is what is being renamed. */
917 ;
919 /* Case 4: Make this into a constant pointer to the object we
920 are to rename and attach the object to the pointer if it is
921 something we can stabilize.
923 From the proper scope, attached objects will be referenced
924 directly instead of indirectly via the pointer to avoid
925 subtle aliasing problems with non-addressable entities.
926 They have to be stable because we must not evaluate the
927 variables in the expression every time the renaming is used.
928 The pointer is called a "renaming" pointer in this case.
930 In the rare cases where we cannot stabilize the renamed
931 object, we just make a "bare" pointer, and the renamed
932 entity is always accessed indirectly through it. */
933 else
934 {
939 /* If the previous attempt at stabilizing failed, there
940 is no point in trying again and we reuse the result
941 without attaching it to the pointer. In this case it
942 will only be used as the initializing expression of
943 the pointer and thus needs no special treatment with
944 regard to multiple evaluations. */
946 ;
948 /* Otherwise, try to stabilize and attach the expression
949 to the pointer if the stabilization succeeds.
951 Note that this might introduce SAVE_EXPRs and we don't
952 check whether we're at the global level or not. This
953 is fine since we are building a pointer initializer and
954 neither the pointer nor the initializing expression can
955 be accessed before the pointer elaboration has taken
956 place in a correct program.
958 These SAVE_EXPRs will be evaluated at the right place
959 by either the evaluation of the initializer for the
960 non-global case or the elaboration code for the global
961 case, and will be attached to the elaboration procedure
962 in the latter case. */
963 else
964 {
965 maybe_stable_expr
971 /* Attaching is actually performed downstream, as soon
972 as we have a VAR_DECL for the pointer we make. */
973 }
975 gnu_expr
980 }
981 }
982 }
984 /* If this is an aliased object whose nominal subtype is unconstrained,
985 the object is a record that contains both the template and
986 the object. If there is an initializer, it will have already
987 been converted to the right type, but we need to create the
988 template if there is no initializer. */
992 /* Beware that padding might have been introduced
993 via maybe_pad_type above. */
996 == RECORD_TYPE
997 && TYPE_CONTAINS_TEMPLATE_P
1000 {
1001 tree template_field
1006 gnu_expr
1007 = gnat_build_constructor
1009 tree_cons
1013 NULL_TREE),
1014 NULL_TREE));
1015 }
1017 /* Convert the expression to the type of the object except in the
1018 case where the object's type is unconstrained or the object's type
1019 is a padded record whose field is of self-referential size. In
1020 the former case, converting will generate unnecessary evaluations
1021 of the CONSTRUCTOR to compute the size and in the latter case, we
1022 want to only copy the actual data. */
1028 && (CONTAINS_PLACEHOLDER_P
1032 /* If this is a pointer and it does not have an initializing
1033 expression, initialize it to NULL, unless the object is
1034 imported. */
1040 /* If we are defining the object and it has an Address clause we must
1041 get the address expression from the saved GCC tree for the
1042 object if the object has a Freeze_Node. Otherwise, we elaborate
1043 the address expression here since the front-end has guaranteed
1044 in that case that the elaboration has no effects. Note that
1045 only the latter mechanism is currently in use. */
1047 {
1048 tree gnu_address
1054 /* Ignore the size. It's either meaningless or was handled
1055 above. */
1057 /* Convert the type of the object to a reference type that can
1058 alias everything as per 13.3(19). */
1059 gnu_type
1067 /* If we don't have an initializing expression for the underlying
1068 variable, the initializing expression for the pointer is the
1069 specified address. Otherwise, we have to make a COMPOUND_EXPR
1070 to assign both the address and the initial value. */
1073 else
1074 gnu_expr
1076 build_binary_op
1079 gnu_address),
1080 gnu_expr),
1081 gnu_address);
1082 }
1084 /* If it has an address clause and we are not defining it, mark it
1085 as an indirect object. Likewise for Stdcall objects that are
1086 imported. */
1090 {
1091 /* Convert the type of the object to a reference type that can
1092 alias everything as per 13.3(19). */
1093 gnu_type
1097 /* No point in taking the address of an initializing expression
1098 that isn't going to be used. */
1101 /* If it has an address clause whose value is known at compile
1102 time, make the object a CONST_DECL. This will avoid a
1103 useless dereference. */
1105 {
1106 Node_Id gnat_address
1110 {
1113 }
1114 }
1117 }
1119 /* If we are at top level and this object is of variable size,
1120 make the actual type a hidden pointer to the real type and
1121 make the initializer be a memory allocation and initialization.
1122 Likewise for objects we aren't defining (presumed to be
1123 external references from other packages), but there we do
1124 not set up an initialization.
1126 If the object's size overflows, make an allocator too, so that
1127 Storage_Error gets raised. Note that we will never free
1128 such memory, so we presume it never will get allocated. */
1133 || (gnu_size
1137 {
1143 /* In case this was a aliased object whose nominal subtype is
1144 unconstrained, the pointer above will be a thin pointer and
1145 build_allocator will automatically make the template.
1147 If we have a template initializer only (that we made above),
1148 pretend there is none and rely on what build_allocator creates
1149 again anyway. Otherwise (if we have a full initializer), get
1150 the data part and feed that to build_allocator.
1152 If we are elaborating a mutable object, tell build_allocator to
1153 ignore a possibly simpler size from the initializer, if any, as
1154 we must allocate the maximum possible size in this case. */
1157 {
1162 {
1163 gnu_alloc_type
1170 else
1171 gnu_expr
1172 = build_component_ref
1176 }
1182 gnat_entity);
1186 }
1187 else
1188 {
1191 }
1192 }
1194 /* If this object would go into the stack and has an alignment larger
1195 than the largest stack alignment the back-end can honor, resort to
1196 a variable of "aligning type". */
1199 {
1200 /* Create the new variable. No need for extra room before the
1201 aligned field as this is in automatic storage. */
1202 tree gnu_new_type
1206 tree gnu_new_var
1211 /* Initialize the aligned field if we have an initializer. */
1213 add_stmt_with_node
1215 build_component_ref
1218 gnu_expr),
1219 gnat_entity);
1221 /* And setup this entity as a reference to the aligned field. */
1223 gnu_expr
1224 = build_unary_op
1232 }
1238 /* Convert the expression to the type of the object except in the
1239 case where the object's type is unconstrained or the object's type
1240 is a padded record whose field is of self-referential size. In
1241 the former case, converting will generate unnecessary evaluations
1242 of the CONSTRUCTOR to compute the size and in the latter case, we
1243 want to only copy the actual data. */
1249 && (CONTAINS_PLACEHOLDER_P
1253 /* If this name is external or there was a name specified, use it,
1254 unless this is a VMS exception object since this would conflict
1255 with the symbol we need to export in addition. Don't use the
1256 Interface_Name if there is an address clause (see CD30005). */
1265 /* If this is constant initialized to a static constant and the
1266 object has an aggregate type, force it to be statically
1267 allocated. */
1283 {
1286 {
1289 }
1290 }
1297 STACK_CHECK_MAX_VAR_SIZE))))
1302 gnat_entity);
1304 /* If this is a public constant or we're not optimizing and we're not
1305 making a VAR_DECL for it, make one just for export or debugger use.
1306 Likewise if the address is taken or if either the object or type is
1307 aliased. Make an external declaration for a reference, unless this
1308 is a Standard entity since there no real symbol at the object level
1309 for these. */
1318 {
1319 tree gnu_corr_var
1323 gnat_entity);
1327 /* As debugging information will be generated for the variable,
1328 do not generate information for the constant. */
1330 }
1332 /* If this is declared in a block that contains a block with an
1333 exception handler, we must force this variable in memory to
1334 suppress an invalid optimization. */
1341 /* Back-annotate Alignment and Esize of the object if not already
1342 known, except for when the object is actually a pointer to the
1343 real object, since alignment and size of a pointer don't have
1344 anything to do with those of the designated object. Note that
1345 we pick the values of the type, not those of the object, to
1346 shield ourselves from low-level platform-dependent adjustments
1347 like alignment promotion. This is both consistent with all the
1348 treatment above, where alignment and size are set on the type of
1349 the object and not on the object directly, and makes it possible
1350 to support confirming representation clauses in all cases. */
1357 {
1360 gnu_object_size
1364 }
1365 }
1369 /* Return a TYPE_DECL for "void" that we previously made. */
1374 /* A special case, for the types Character and Wide_Character in
1375 Standard, we do not list all the literals. So if the literals
1376 are not specified, make this an unsigned type. */
1378 {
1382 /* Set the TYPE_STRING_FLAG for Ada Character and
1383 Wide_Character types. This is needed by the dwarf-2 debug writer to
1384 distinguish between unsigned integer types and character types. */
1387 }
1389 /* Normal case of non-character type, or non-Standard character type */
1390 {
1391 /* Here we have a list of enumeral constants in First_Literal.
1392 We make a CONST_DECL for each and build into GNU_LITERAL_LIST
1393 the list to be places into TYPE_FIELDS. Each node in the list
1394 is a TREE_LIST node whose TREE_VALUE is the literal name
1395 and whose TREE_PURPOSE is the value of the literal.
1397 Esize contains the number of bits needed to represent the enumeral
1398 type, Type_Low_Bound also points to the first literal and
1399 Type_High_Bound points to the last literal. */
1401 Entity_Id gnat_literal;
1406 else
1414 {
1416 gnu_type);
1417 tree gnu_literal
1425 }
1429 /* Note that the bounds are updated at the end of this function
1430 because to avoid an infinite recursion when we get the bounds of
1431 this type, since those bounds are objects of this type. */
1432 }
1438 /* For integer types, just make a signed type the appropriate number
1439 of bits. */
1444 /* For modular types, make the unsigned type of the proper number of
1445 bits and then set up the modulus, if required. */
1446 {
1448 tree gnu_modulus;
1454 /* Find the smallest mode at least ESIZE bits wide and make a class
1455 using that mode. */
1460 ;
1467 /* Get the modulus in this type. If it overflows, assume it is because
1468 it is equal to 2**Esize. Note that there is no overflow checking
1469 done on unsigned type, so we detect the overflow by looking for
1470 a modulus of zero, which is otherwise invalid. */
1474 {
1479 }
1481 /* If we have to set TYPE_PRECISION different from its natural value,
1482 make a subtype to do do. Likewise if there is a modulus and
1483 it is not one greater than TYPE_MAX_VALUE. */
1487 {
1505 }
1506 }
1515 /* For integral subtypes, we make a new INTEGER_TYPE. Note
1516 that we do not want to call build_range_type since we would
1517 like each subtype node to be distinct. This will be important
1518 when memory aliasing is implemented.
1520 The TREE_TYPE field of the INTEGER_TYPE we make points to the
1521 parent type; this fact is used by the arithmetic conversion
1522 functions.
1524 We elaborate the Ancestor_Subtype if it is not in the current
1525 unit and one of our bounds is non-static. We do this to ensure
1526 consistent naming in the case where several subtypes share the same
1527 bounds by always elaborating the first such subtype first, thus
1528 using its name. */
1541 /* Set the precision to the Esize except for bit-packed arrays and
1542 subtypes of Standard.Boolean. */
1545 {
1548 }
1557 gnat_entity,
1564 gnat_entity,
1568 /* One of the above calls might have caused us to be elaborated,
1569 so don't blow up if so. */
1571 {
1574 }
1579 /* This should be an unsigned type if the lower bound is constant
1580 and non-negative or if the base type is unsigned; a signed type
1581 otherwise. */
1591 /* Inherit our alias set from what we're a subtype of. Subtypes
1592 are not different types and a pointer can designate any instance
1593 within a subtype hierarchy. */
1596 /* If the type we are dealing with is to represent a packed array,
1597 we need to have the bits left justified on big-endian targets
1598 and right justified on little-endian targets. We also need to
1599 ensure that when the value is read (e.g. for comparison of two
1600 such values), we only get the good bits, since the unused bits
1601 are uninitialized. Both goals are accomplished by wrapping the
1602 modular value in an enclosing struct. */
1605 {
1607 tree gnu_field;
1614 /* Propagate the alignment of the modular type to the record.
1615 This means that bitpacked arrays have "ceil" alignment for
1616 their size, which may seem counter-intuitive but makes it
1617 possible to easily overlay them on modular types. */
1621 /* Create a stripped-down declaration of the original type, mainly
1622 for debugging. */
1626 /* Don't notify the field as "addressable", since we won't be taking
1627 it's address and it would prevent create_field_decl from making a
1628 bitfield. */
1637 }
1639 /* If the type we are dealing with has got a smaller alignment than the
1640 natural one, we need to wrap it up in a record type and under-align
1641 the latter. We reuse the padding machinery for this purpose. */
1646 {
1648 tree gnu_field;
1656 /* Create a stripped-down declaration of the original type, mainly
1657 for debugging. */
1661 /* Don't notify the field as "addressable", since we won't be taking
1662 it's address and it would prevent create_field_decl from making a
1663 bitfield. */
1672 }
1674 /* Otherwise reset the alignment lest we computed it above. */
1675 else
1681 /* If this is a VAX floating-point type, use an integer of the proper
1682 size. All the operations will be handled with ASM statements. */
1684 {
1689 sizetype));
1691 }
1693 /* The type of the Low and High bounds can be our type if this is
1694 a type from Standard, so set them at the end of the function. */
1702 {
1705 }
1707 {
1734 /* One of the above calls might have caused us to be elaborated,
1735 so don't blow up if so. */
1737 {
1740 }
1744 /* Inherit our alias set from what we're a subtype of, as for
1745 integer subtypes. */
1747 }
1750 /* Array and String Types and Subtypes
1752 Unconstrained array types are represented by E_Array_Type and
1753 constrained array types are represented by E_Array_Subtype. There
1754 are no actual objects of an unconstrained array type; all we have
1755 are pointers to that type.
1757 The following fields are defined on array types and subtypes:
1759 Component_Type Component type of the array.
1760 Number_Dimensions Number of dimensions (an int).
1761 First_Index Type of first index. */
1765 {
1771 int firstdim
1773 int nextdim
1780 tree gnu_max_size_unit;
1781 Entity_Id gnat_ind_subtype;
1782 Entity_Id gnat_ind_base_subtype;
1783 tree gnu_template_reference;
1784 tree tem;
1789 /* Make a node for the array. If we are not defining the array
1790 suppress expanding incomplete types. */
1796 /* Build the fat pointer type. Use a "void *" object instead of
1797 a pointer to the array type since we don't have the array type
1798 yet (it will reference the fat pointer via the bounds). */
1801 ptr_void_type_node,
1804 gnu_ptr_template,
1807 /* Make sure we can put this into a register. */
1810 /* Do not finalize this record type since the types of its fields
1811 are still incomplete at this point. */
1815 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1816 is the fat pointer. This will be used to access the individual
1817 fields once we build them. */
1821 gnu_template_reference
1825 /* Now create the GCC type for each index and add the fields for
1826 that index to the template. */
1828 gnat_ind_base_subtype
1834 {
1836 tree gnu_ind_subtype
1838 tree gnu_base_subtype
1840 tree gnu_base_min
1842 tree gnu_base_max
1846 /* Make the FIELD_DECLs for the minimum and maximum of this
1847 type and then make extractions of that field from the
1848 template. */
1851 gnu_ind_subtype,
1855 gnu_ind_subtype,
1864 /* We can't use build_component_ref here since the template
1865 type isn't complete yet. */
1868 NULL_TREE);
1871 NULL_TREE);
1874 /* Make a range type with the new ranges, but using
1875 the Ada subtype. Then we convert to sizetype. */
1881 gnat_entity);
1882 /* Update the maximum size of the array, in elements. */
1883 gnu_max_size
1887 gnu_base_min)));
1891 }
1894 gnu_template_fields
1897 /* Install all the fields into the template. */
1901 /* Now make the array of arrays and update the pointer to the array
1902 in the fat pointer. Note that it is the first field. */
1905 /* Try to get a smaller form of the component if needed. */
1918 /* Get and validate any specified Component_Size, but if Packed,
1919 ignore it since the front end will have taken care of it. */
1920 gnu_comp_size
1922 gnat_entity,
1927 /* If the component type is a RECORD_TYPE that has a self-referential
1928 size, use the maxium size. */
1934 {
1935 tree orig_tem;
1940 /* If a padding record was made, declare it now since it will
1941 never be declared otherwise. This is necessary to ensure
1942 that its subtrees are properly marked. */
1945 gnat_entity);
1946 }
1952 /* If Component_Size is not already specified, annotate it with the
1953 size of the component. */
1963 gnu_max_size),
1967 {
1972 }
1974 /* If an alignment is specified, use it if valid. But ignore it for
1975 types that represent the unpacked base type for packed arrays. If
1976 the alignment was requested with an explicit user alignment clause,
1977 state so. */
1980 {
1987 }
1993 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
1994 corresponding fat pointer. */
2001 /* If the maximum size doesn't overflow, use it. */
2016 /* Give the fat pointer type a name. */
2021 /* Create the type to be used as what a thin pointer designates: an
2022 record type for the object and its template with the field offsets
2023 shifted to have the template at a negative offset. */
2031 /* Give the thin pointer type a name. */
2035 gnat_entity);
2036 }
2042 /* This is the actual data type for array variables. Multidimensional
2043 arrays are implemented in the gnu tree as arrays of arrays. Note
2044 that for the moment arrays which have sparse enumeration subtypes as
2045 index components create sparse arrays, which is obviously space
2046 inefficient but so much easier to code for now.
2048 Also note that the subtype never refers to the unconstrained
2049 array type, which is somewhat at variance with Ada semantics.
2051 First check to see if this is simply a renaming of the array
2052 type. If so, the result is the array type. */
2057 else
2058 {
2061 int first_dim
2064 int next_dim
2066 Entity_Id gnat_ind_subtype;
2067 Entity_Id gnat_ind_base_subtype;
2072 tree gnu_max_size_unit;
2076 /* First create the gnu types for each index. Create types for
2077 debugging information to point to the index types if the
2078 are not integer types, have variable bounds, or are
2079 wider than sizetype. */
2082 gnat_ind_base_subtype
2088 {
2089 tree gnu_index_subtype
2091 tree gnu_min
2093 tree gnu_max
2095 tree gnu_base_subtype
2097 tree gnu_base_min
2099 tree gnu_base_max
2102 tree gnu_base_base_min
2104 tree gnu_base_base_max
2106 tree gnu_high;
2107 tree gnu_this_max;
2109 /* If the minimum and maximum values both overflow in
2110 SIZETYPE, but the difference in the original type
2111 does not overflow in SIZETYPE, ignore the overflow
2112 indications. */
2120 && (!TREE_OVERFLOW
2124 {
2127 }
2129 /* Similarly, if the range is null, use bounds of 1..0 for
2130 the sizetype bounds. */
2142 /* Now compute the size of this bound. We need to provide
2143 GCC with an upper bound to use but have to deal with the
2144 "superflat" case. There are three ways to do this. If we
2145 can prove that the array can never be superflat, we can
2146 just use the high bound of the index subtype. If we can
2147 prove that the low bound minus one can't overflow, we
2148 can do this as MAX (hb, lb - 1). Otherwise, we have to use
2149 the expression hb >= lb ? hb : lb - 1. */
2152 /* See if the base array type is already flat. If it is, we
2153 are probably compiling an ACVC test, but it will cause the
2154 code below to malfunction if we don't handle it specially. */
2162 /* If gnu_high is now an integer which overflowed, the array
2163 cannot be superflat. */
2170 else
2171 gnu_high
2172 = build_cond_expr
2179 gnat_entity);
2181 /* Also compute the maximum size of the array. Here we
2182 see if any constraint on the index type of the base type
2183 can be used in the case of self-referential bound on
2184 the index type of the subtype. We look for a non-"infinite"
2185 and non-self-referential bound from any type involved and
2186 handle each bound separately. */
2215 gnu_this_max
2219 gnu_base_min)),
2220 size_zero_node);
2226 gnu_max_size
2240 }
2242 /* Then flatten: create the array of arrays. For an array type
2243 used to implement a packed array, get the component type from
2244 the original array type since the representation clauses that
2245 can affect it are on the latter. */
2248 {
2253 /* One of the above calls might have caused us to be elaborated,
2254 so don't blow up if so. */
2256 {
2259 }
2260 }
2261 else
2262 {
2265 /* One of the above calls might have caused us to be elaborated,
2266 so don't blow up if so. */
2268 {
2271 }
2273 /* Try to get a smaller form of the component if needed. */
2283 /* Get and validate any specified Component_Size, but if Packed,
2284 ignore it since the front end will have taken care of it. */
2285 gnu_comp_size
2287 gnat_entity,
2292 /* If the component type is a RECORD_TYPE that has a
2293 self-referential size, use the maxium size. */
2300 {
2301 tree orig_gnu_type;
2302 gnu_type
2308 /* If a padding record was made, declare it now since it
2309 will never be declared otherwise. This is necessary
2310 to ensure that its subtrees are properly marked. */
2314 }
2320 }
2329 {
2334 }
2336 /* If we are at file level and this is a multi-dimensional array, we
2337 need to make a variable corresponding to the stride of the
2338 inner dimensions. */
2340 {
2342 tree gnu_arr_type;
2348 {
2356 /* ??? For now, store the size as a multiple of the
2357 alignment of the element type in bytes so that we
2358 can see the alignment from the tree. */
2360 = build_binary_op
2362 elaborate_expression_1
2372 /* ??? create_type_decl is not invoked on the inner types so
2373 the MULT_EXPR node built above will never be marked. */
2375 }
2376 }
2378 /* If we need to write out a record type giving the names of
2379 the bounds, do it now. */
2381 {
2384 tree gnu_field;
2390 {
2391 tree gnu_type_name
2398 integer_type_node,
2399 gnu_bound_rec_type,
2403 }
2411 add_parallel_type
2413 }
2421 /* If our size depends on a placeholder and the maximum size doesn't
2422 overflow, use it. */
2429 {
2435 }
2437 /* Set our alias set to that of our base type. This gives all
2438 array subtypes the same alias set. */
2440 }
2442 /* If this is a packed type, make this type the same as the packed
2443 array type, but do some adjusting in the type first. */
2446 {
2447 Entity_Id gnat_index;
2448 tree gnu_inner_type;
2450 /* First finish the type we had been making so that we output
2451 debugging information for it */
2452 gnu_type
2455 | (TYPE_QUAL_VOLATILE
2463 /* Save it as our equivalent in case the call below elaborates
2464 this type again. */
2479 /* We need to point the type we just made to our index type so
2480 the actual bounds can be put into a template. */
2486 {
2488 {
2489 /* The TYPE_ACTUAL_BOUNDS field is also used for the modulus.
2490 If it is, we need to make another type. */
2492 {
2493 tree gnu_subtype;
2510 }
2513 }
2519 SET_TYPE_ACTUAL_BOUNDS
2526 SET_TYPE_ACTUAL_BOUNDS
2533 }
2534 }
2536 /* Abort if packed array with no packed array type field set. */
2537 else
2543 /* Create the type for a string literal. */
2544 {
2545 Entity_Id gnat_full_type
2550 tree gnu_string_array_type
2552 tree gnu_string_index_type
2555 tree gnu_lower_bound
2560 tree gnu_upper_bound
2562 gnu_lower_bound,
2564 tree gnu_range_type
2567 tree gnu_index_type
2574 gnu_type
2576 gnu_index_type);
2578 }
2581 /* Record Types and Subtypes
2583 The following fields are defined on record types:
2585 Has_Discriminants True if the record has discriminants
2586 First_Discriminant Points to head of list of discriminants
2587 First_Entity Points to head of list of fields
2588 Is_Tagged_Type True if the record is tagged
2590 Implementation of Ada records and discriminated records:
2592 A record type definition is transformed into the equivalent of a C
2593 struct definition. The fields that are the discriminants which are
2594 found in the Full_Type_Declaration node and the elements of the
2595 Component_List found in the Record_Type_Definition node. The
2596 Component_List can be a recursive structure since each Variant of
2597 the Variant_Part of the Component_List has a Component_List.
2599 Processing of a record type definition comprises starting the list of
2600 field declarations here from the discriminants and the calling the
2601 function components_to_record to add the rest of the fields from the
2602 component list and return the gnu type node. The function
2603 components_to_record will call itself recursively as it traverses
2604 the tree. */
2608 {
2609 gnu_type
2610 = build_complex_type
2611 (get_unpadded_type
2614 (Component_List
2615 (Type_Definition
2619 }
2621 {
2624 Entity_Id gnat_field;
2625 tree gnu_field;
2627 tree gnu_get_parent;
2628 /* Set PACKED in keeping with gnat_to_gnu_field. */
2629 int packed
2641 bool is_extension
2645 /* See if all fields have a rep clause. Stop when we find one
2646 that doesn't. */
2655 /* If this is a record extension, go a level further to find the
2656 record definition. Also, verify we have a Parent_Subtype. */
2658 {
2665 }
2667 /* Make a node for the record. If we are not defining the record,
2668 suppress expanding incomplete types. */
2676 /* If both a size and rep clause was specified, put the size in
2677 the record type now so that it can get the proper mode. */
2681 /* Always set the alignment here so that it can be used to
2682 set the mode, if it is making the alignment stricter. If
2683 it is invalid, it will be checked again below. If this is to
2684 be Atomic, choose a default alignment of a word unless we know
2685 the size and it's smaller. */
2692 /* If a type needs strict alignment, the minimum size will be the
2693 type size instead of the RM size (see validate_size). Cap the
2694 alignment, lest it causes this type size to become too large. */
2697 {
2702 }
2703 else
2706 /* If we have a Parent_Subtype, make a field for the parent. If
2707 this record has rep clauses, force the position to zero. */
2709 {
2711 tree gnu_parent;
2713 /* A major complexity here is that the parent subtype will
2714 reference our discriminants in its Discriminant_Constraint
2715 list. But those must reference the parent component of this
2716 record which is of the parent subtype we have not built yet!
2717 To break the circle we first build a dummy COMPONENT_REF which
2718 represents the "get to the parent" operation and initialize
2719 each of those discriminants to a COMPONENT_REF of the above
2720 dummy parent referencing the corresponding discriminant of the
2721 base type of the parent subtype. */
2725 void_type_node),
2726 NULL_TREE);
2733 save_gnu_tree
2737 gnu_get_parent,
2740 NULL_TREE),
2743 /* Then we build the parent subtype. */
2746 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
2747 initially built. The discriminants must reference the fields
2748 of the parent subtype and not those of its base type for the
2749 placeholder machinery to properly work. */
2755 {
2765 }
2767 /* The "get to the parent" COMPONENT_REF must be given its
2768 proper type... */
2771 /* ...and reference the _parent field of this record. */
2772 gnu_field_list
2780 }
2782 /* Make the fields for the discriminants and put them into the record
2783 unless it's an Unchecked_Union. */
2788 {
2789 /* If this is a record extension and this discriminant
2790 is the renaming of another discriminant, we've already
2791 handled the discriminant above. */
2796 gnu_field
2799 /* Make an expression using a PLACEHOLDER_EXPR from the
2800 FIELD_DECL node just created and link that with the
2801 corresponding GNAT defining identifier. Then add to the
2802 list of fields. */
2811 {
2814 }
2815 }
2817 /* Put the discriminants into the record (backwards), so we can
2818 know the appropriate discriminant to use for the names of the
2819 variants. */
2822 /* Add the listed fields into the record and finish it up. */
2828 /* We used to remove the associations of the discriminants and
2829 _Parent for validity checking, but we may need them if there's
2830 Freeze_Node for a subtype used in this record. */
2834 /* If it is a tagged record force the type to BLKmode to insure
2835 that these objects will always be placed in memory. Do the
2836 same thing for limited record types. */
2840 /* If this is a derived type, we must make the alias set of this type
2841 the same as that of the type we are derived from. We assume here
2842 that the other type is already frozen. */
2848 /* Fill in locations of fields. */
2851 /* If there are any entities in the chain corresponding to
2852 components that we did not elaborate, ensure we elaborate their
2853 types if they are Itypes. */
2861 }
2865 /* If an equivalent type is present, that is what we should use.
2866 Otherwise, fall through to handle this like a record subtype
2867 since it may have constraints. */
2869 {
2873 }
2875 /* ... fall through ... */
2879 /* If Cloned_Subtype is Present it means this record subtype has
2880 identical layout to that type or subtype and we should use
2881 that GCC type for this one. The front end guarantees that
2882 the component list is shared. */
2884 {
2888 }
2890 /* Otherwise, first ensure the base type is elaborated. Then, if we are
2891 changing the type, make a new type with each field having the
2892 type of the field in the new subtype but having the position
2893 computed by transforming every discriminant reference according
2894 to the constraints. We don't see any difference between
2895 private and nonprivate type here since derivations from types should
2896 have been deferred until the completion of the private type. */
2897 else
2898 {
2900 tree gnu_base_type;
2901 tree gnu_orig_type;
2906 /* Get the base type initially for its alignment and sizes. But
2907 if it is a padded type, we do all the other work with the
2908 unpadded type. */
2914 else
2918 {
2921 }
2923 /* When the type has discriminants, and these discriminants
2924 affect the shape of what it built, factor them in.
2926 If we are making a subtype of an Unchecked_Union (must be an
2927 Itype), just return the type.
2929 We can't just use Is_Constrained because private subtypes without
2930 discriminants of full types with discriminants with default
2931 expressions are Is_Constrained but aren't constrained! */
2939 {
2940 Entity_Id gnat_field;
2942 tree gnu_pos_list
2945 BIGGEST_ALIGNMENT);
2946 tree gnu_subst_list
2948 definition);
2949 tree gnu_temp;
2955 /* Set the size, alignment and alias set of the new type to
2956 match that of the old one, doing required substitutions.
2957 We do it this early because we need the size of the new
2958 type below to discard old fields if necessary. */
2984 SET_TYPE_ADA_SIZE
2998 {
2999 tree gnu_old_field
3002 tree gnu_offset
3004 gnu_pos_list));
3007 tree gnu_field_type
3011 unsigned int offset_align
3014 tree gnu_field;
3016 /* If there was a component clause, the field types must be
3017 the same for the type and subtype, so copy the data from
3018 the old field to avoid recomputation here. Also if the
3019 field is justified modular and the optimization in
3020 gnat_to_gnu_field was applied. */
3027 {
3030 }
3032 /* If the old field was packed and of constant size, we
3033 have to get the old size here, as it might differ from
3034 what the Etype conveys and the latter might overlap
3035 onto the following field. Try to arrange the type for
3036 possible better packing along the way. */
3040 {
3045 gnu_field_type
3047 }
3056 /* If the position is now a constant, we can set it as the
3057 position of the field when we make it. Otherwise, we need
3058 to deal with it specially below. */
3060 {
3063 /* Discard old fields that are outside the new type.
3064 This avoids confusing code scanning it to decide
3065 how to pass it to functions on some platforms. */
3072 }
3074 gnu_field
3075 = create_field_decl
3081 {
3090 bitsize_unit_node));
3092 }
3096 SET_DECL_ORIGINAL_FIELD
3107 }
3109 /* Now go through the entities again looking for Itypes that
3110 we have not elaborated but should (e.g., Etypes of fields
3111 that have Original_Components). */
3119 /* Do not finalize it since we're going to modify it below. */
3123 /* Finalize size and mode. */
3130 /* Fill in locations of fields. */
3133 /* We've built a new type, make an XVS type to show what this
3134 is a subtype of. Some debuggers require the XVS type to be
3135 output first, so do it in that order. */
3137 {
3148 integer_type_node,
3149 gnu_subtype_marker,
3155 gnu_subtype_marker);
3156 }
3158 /* Now we can finalize it. */
3160 }
3162 /* Otherwise, go down all the components in the new type and
3163 make them equivalent to those in the base type. */
3164 else
3171 gnat_to_gnu_field_decl
3173 }
3177 /* Use the special descriptor type for dispatch tables if needed,
3178 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3179 Note that we are only required to do so for static tables in
3180 order to be compatible with the C++ ABI, but Ada 2005 allows
3181 to extend library level tagged types at the local level so
3182 we do it in the non-static case as well. */
3185 {
3189 }
3191 /* ... fall through ... */
3194 /* If we are not defining this entity, and we have incomplete
3195 entities being processed above us, make a dummy type and
3196 fill it in later. */
3198 {
3202 gnu_type
3203 = build_pointer_type
3218 }
3220 /* ... fall through ... */
3227 {
3230 bool is_from_limited_with
3234 /* Get the "full view" of this entity. If this is an incomplete
3235 entity from a limited with, treat its non-limited view as the full
3236 view. Otherwise, if this is an incomplete or private type, use the
3237 full view. In the former case, we might point to a private type,
3238 in which case, we need its full view. Also, we want to look at the
3239 actual type used for the representation, so this takes a total of
3240 three steps. */
3241 Entity_Id gnat_desig_full_direct_first
3245 Entity_Id gnat_desig_full_direct
3246 = ((is_from_limited_with
3251 Entity_Id gnat_desig_full
3254 /* This the type actually used to represent the designated type,
3255 either gnat_desig_full or gnat_desig_equiv. */
3256 Entity_Id gnat_desig_rep;
3258 /* Nonzero if this is a pointer to an unconstrained array. */
3261 /* We want to know if we'll be seeing the freeze node for any
3262 incomplete type we may be pointing to. */
3263 bool in_main_unit
3268 /* Nonzero if we make a dummy type here. */
3270 /* Nonzero if the dummy is a fat pointer. */
3278 /* If either the designated type or its full view is an unconstrained
3279 array subtype, replace it with the type it's a subtype of. This
3280 avoids problems with multiple copies of unconstrained array types.
3281 Likewise, if the designated type is a subtype of an incomplete
3282 record type, use the parent type to avoid order of elaboration
3283 issues. This can lose some code efficiency, but there is no
3284 alternative. */
3295 /* Now set the type that actually marks the representation of
3296 the designated type and also flag whether we have a unconstrained
3297 array. */
3299 is_unconstrained_array
3303 /* If we are pointing to an incomplete type whose completion is an
3304 unconstrained array, make a fat pointer type. The two types in our
3305 fields will be pointers to dummy nodes and will be replaced in
3306 update_pointer_to. Similarly, if the type itself is a dummy type or
3307 an unconstrained array. Also make a dummy TYPE_OBJECT_RECORD_TYPE
3308 in case we have any thin pointers to it. */
3319 {
3320 tree gnu_old
3324 tree fields;
3326 /* Show the dummy we get will be a fat pointer. */
3329 /* If the call above got something that has a pointer, that
3330 pointer is our type. This could have happened either
3331 because the type was elaborated or because somebody
3332 else executed the code below. */
3335 {
3356 fields
3358 create_field_decl
3360 gnu_ptr_array,
3363 gnu_ptr_template,
3366 /* Make sure we can place this into a register. */
3371 /* Do not finalize this record type since the types of
3372 its fields are incomplete. */
3380 }
3381 }
3383 /* If we already know what the full type is, use it. */
3388 /* Get the type of the thing we are to point to and build a pointer
3389 to it. If it is a reference to an incomplete or private type with a
3390 full view that is a record, make a dummy type node and get the
3391 actual type later when we have verified it is safe. */
3397 /* Likewise if we are pointing to a record or array and we
3398 are to defer elaborating incomplete types. We do this
3399 since this access type may be the full view of some
3400 private type. Note that the unconstrained array case is
3401 handled above. */
3407 /* If this is a reference from a limited_with type back to our
3408 main unit and there's a Freeze_Node for it, either we have
3409 already processed the declaration and made the dummy type,
3410 in which case we just reuse the latter, or we have not yet,
3411 in which case we make the dummy type and it will be reused
3412 when the declaration is processed. In both cases, the
3413 pointer eventually created below will be automatically
3414 adjusted when the Freeze_Node is processed. Note that the
3415 unconstrained array case is handled above. */
3418 {
3421 }
3423 /* Otherwise handle the case of a pointer to itself. */
3425 {
3426 gnu_type
3430 }
3432 /* If expansion is disabled, the equivalent type of a concurrent
3433 type is absent, so build a dummy pointer type. */
3437 /* Finally, handle the straightforward case where we can just
3438 elaborate our designated type and point to it. */
3439 else
3442 /* It is possible that a call to gnat_to_gnu_type above resolved our
3443 type. If so, just return it. */
3445 {
3448 }
3450 /* If we have a GCC type for the designated type, possibly modify it
3451 if we are pointing only to constant objects and then make a pointer
3452 to it. Don't do this for unconstrained arrays. */
3454 {
3457 {
3458 gnu_desig_type
3459 = build_qualified_type
3463 /* Some extra processing is required if we are building a
3464 pointer to an incomplete type (in the GCC sense). We might
3465 have such a type if we just made a dummy, or directly out
3466 of the call to gnat_to_gnu_type above if we are processing
3467 an access type for a record component designating the
3468 record type itself. */
3470 {
3471 /* We must ensure that the pointer to variant we make will
3472 be processed by update_pointer_to when the initial type
3473 is completed. Pretend we made a dummy and let further
3474 processing act as usual. */
3477 /* We must ensure that update_pointer_to will not retrieve
3478 the dummy variant when building a properly qualified
3479 version of the complete type. We take advantage of the
3480 fact that get_qualified_type is requiring TYPE_NAMEs to
3481 match to influence build_qualified_type and then also
3482 update_pointer_to here. */
3485 }
3486 }
3488 gnu_type
3491 }
3493 /* If we are not defining this object and we made a dummy pointer,
3494 save our current definition, evaluate the actual type, and replace
3495 the tentative type we made with the actual one. If we are to defer
3496 actually looking up the actual type, make an entry in the
3497 deferred list. If this is from a limited with, we have to defer
3498 to the end of the current spec in two cases: first if the
3499 designated type is in the current unit and second if the access
3500 type is. */
3502 {
3503 tree gnu_old_type
3509 gnu_type
3510 = build_pointer_type
3511 (TYPE_OBJECT_RECORD_TYPE
3523 && ! (is_from_limited_with
3524 && (in_main_unit
3529 /* Note that the call to gnat_to_gnu_type here might have
3530 updated gnu_old_type directly, in which case it is not a
3531 dummy type any more when we get into update_pointer_to.
3533 This may happen for instance when the designated type is a
3534 record type, because their elaboration starts with an
3535 initial node from make_dummy_type, which may yield the same
3536 node as the one we got.
3538 Besides, variants of this non-dummy type might have been
3539 created along the way. update_pointer_to is expected to
3540 properly take care of those situations. */
3541 else
3542 {
3547 = (is_from_limited_with
3548 && (in_main_unit
3556 }
3557 }
3558 }
3565 else
3566 {
3567 /* The runtime representation is the equivalent type. */
3570 }
3583 /* We treat this as identical to its base type; any constraint is
3584 meaningful only to the front end.
3586 The designated type must be elaborated as well, if it does
3587 not have its own freeze node. Designated (sub)types created
3588 for constrained components of records with discriminants are
3589 not frozen by the front end and thus not elaborated by gigi,
3590 because their use may appear before the base type is frozen,
3591 and because it is not clear that they are needed anywhere in
3592 Gigi. With the current model, there is no correct place where
3593 they could be elaborated. */
3600 {
3601 /* If we are not defining this entity, and we have incomplete
3602 entities being processed above us, make a dummy type and
3603 elaborate it later. */
3605 {
3608 tree gnu_ptr_type
3609 = build_pointer_type
3616 }
3619 Incomplete_Or_Private_Kind))
3622 }
3627 /* Subprogram Entities
3629 The following access functions are defined for subprograms (functions
3630 or procedures):
3632 First_Formal The first formal parameter.
3633 Is_Imported Indicates that the subprogram has appeared in
3634 an INTERFACE or IMPORT pragma. For now we
3635 assume that the external language is C.
3636 Is_Exported Likewise but for an EXPORT pragma.
3637 Is_Inlined True if the subprogram is to be inlined.
3639 In addition for function subprograms we have:
3641 Etype Return type of the function.
3643 Each parameter is first checked by calling must_pass_by_ref on its
3644 type to determine if it is passed by reference. For parameters which
3645 are copied in, if they are Ada In Out or Out parameters, their return
3646 value becomes part of a record which becomes the return type of the
3647 function (C function - note that this applies only to Ada procedures
3648 so there is no Ada return type). Additional code to store back the
3649 parameters will be generated on the caller side. This transformation
3650 is done here, not in the front-end.
3652 The intended result of the transformation can be seen from the
3653 equivalent source rewritings that follow:
3655 struct temp {int a,b};
3656 procedure P (A,B: In Out ...) is temp P (int A,B)
3657 begin {
3658 .. ..
3659 end P; return {A,B};
3660 }
3662 temp t;
3663 P(X,Y); t = P(X,Y);
3664 X = t.a , Y = t.b;
3666 For subprogram types we need to perform mainly the same conversions to
3667 GCC form that are needed for procedures and function declarations. The
3668 only difference is that at the end, we make a type declaration instead
3669 of a function declaration. */
3674 {
3675 /* The first GCC parameter declaration (a PARM_DECL node). The
3676 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3677 actually is the head of this parameter list. */
3679 /* Likewise for the stub associated with an exported procedure. */
3681 /* The type returned by a function. If the subprogram is a procedure
3682 this type should be void_type_node. */
3684 /* List of fields in return type of procedure with copy-in copy-out
3685 parameters. */
3687 /* Non-null for subprograms containing parameters passed by copy-in
3688 copy-out (Ada In Out or Out parameters not passed by reference),
3689 in which case it is the list of nodes used to specify the values of
3690 the in out/out parameters that are returned as a record upon
3691 procedure return. The TREE_PURPOSE of an element of this list is
3692 a field of the record and the TREE_VALUE is the PARM_DECL
3693 corresponding to that field. This list will be saved in the
3694 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3696 /* If an import pragma asks to map this subprogram to a GCC builtin,
3697 this is the builtin DECL node. */
3699 /* For the stub associated with an exported procedure. */
3702 Entity_Id gnat_param;
3705 bool extern_flag
3717 /* A parameter may refer to this type, so defer completion
3718 of any incomplete types. */
3721 /* If the subprogram has an alias, it is probably inherited, so
3722 we can use the original one. If the original "subprogram"
3723 is actually an enumeration literal, it may be the first use
3724 of its type, so we must elaborate that type now. */
3726 {
3733 /* Elaborate any Itypes in the parameters of this entity. */
3741 }
3743 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3744 corresponding DECL node.
3746 We still want the parameter associations to take place because the
3747 proper generation of calls depends on it (a GNAT parameter without
3748 a corresponding GCC tree has a very specific meaning), so we don't
3749 just break here. */
3753 /* ??? What if we don't find the builtin node above ? warn ? err ?
3754 In the current state we neither warn nor err, and calls will just
3755 be handled as for regular subprograms. */
3760 /* If this function returns by reference, make the actual
3761 return type of this function the pointer and mark the decl. */
3763 {
3766 }
3768 /* If the Mechanism is By_Reference, ensure the return type uses
3769 the machine's by-reference mechanism, which may not the same
3770 as above (e.g., it might be by passing a fake parameter). */
3773 {
3776 /* We expect this bit to be reset by gigi shortly, so can avoid a
3777 type node copy here. This actually also prevents troubles with
3778 the generation of debug information for the function, because
3779 we might have issued such info for this type already, and would
3780 be attaching a distinct type node to the function if we made a
3781 copy here. */
3782 }
3784 /* If we are supposed to return an unconstrained array,
3785 actually return a fat pointer and make a note of that. Return
3786 a pointer to an unconstrained record of variable size. */
3788 {
3791 }
3793 /* If the type requires a transient scope, the result is allocated
3794 on the secondary stack, so the result type of the function is
3795 just a pointer. */
3797 {
3800 }
3802 /* If the type is a padded type and the underlying type would not
3803 be passed by reference or this function has a foreign convention,
3804 return the underlying type. */
3812 /* If the return type has a non-constant size, we convert the function
3813 into a procedure and its caller will pass a pointer to an object as
3814 the first parameter when we call the function. This can happen for
3815 an unconstrained type with a maximum size or a constrained type with
3816 a size not known at compile time. */
3819 {
3821 gnu_param_list
3826 }
3828 /* If the return type has a size that overflows, we cannot have
3829 a function that returns that type. This usage doesn't make
3830 sense anyway, so give an error here. */
3834 {
3836 gnat_entity);
3842 }
3844 /* Look at all our parameters and get the type of
3845 each. While doing this, build a copy-out structure if
3846 we need one. */
3848 /* Loop over the parameters and get their associated GCC tree.
3849 While doing this, build a copy-out structure if we need one. */
3853 {
3860 /* Builtins are expanded inline and there is no real call sequence
3861 involved. So the type expected by the underlying expander is
3862 always the type of each argument "as is". */
3865 /* Handle the first parameter of a valued procedure specially. */
3868 /* Otherwise, see if a Mechanism was supplied that forced this
3869 parameter to be passed one way or another. */
3872 ;
3881 {
3885 mech))
3887 else
3889 }
3890 else
3891 {
3894 }
3896 gnu_param
3901 /* We are returned either a PARM_DECL or a type if no parameter
3902 needs to be passed; in either case, adjust the type. */
3905 else
3906 {
3909 }
3912 {
3913 /* If it's an exported subprogram, we build a parameter list
3914 in parallel, in case we need to emit a stub for it. */
3916 {
3917 gnu_stub_param_list
3919 /* Change By_Descriptor parameter to By_Reference for
3920 the internal version of an exported subprogram. */
3922 {
3923 gnu_param
3928 }
3929 else
3931 }
3938 /* If a parameter is a pointer, this function may modify
3939 memory through it and thus shouldn't be considered
3940 a pure function. Also, the memory may be modified
3941 between two calls, so they can't be CSE'ed. The latter
3942 case also handles by-ref parameters. */
3946 }
3949 {
3951 {
3956 }
3965 gnu_return_list);
3966 }
3967 }
3969 /* Do not compute record for out parameters if subprogram is
3970 stubbed since structures are incomplete for the back-end. */
3975 /* If we have a CICO list but it has only one entry, we convert
3976 this function into a function that simply returns that one
3977 object. */
3982 prepend_one_attribute_to
3985 gnat_entity);
3987 /* If we are on a target where stack realignment is needed for 'main'
3988 to honor GCC's implicit expectations (stack alignment greater than
3989 what the base ABI guarantees), ensure we do the same for foreign
3990 convention subprograms as they might be used as callbacks from code
3991 breaking such expectations. Note that this applies to task entry
3992 points in particular. */
3995 prepend_one_attribute_to
3998 gnat_entity);
4000 /* The lists have been built in reverse. */
4010 gnu_type
4016 gnu_stub_type
4021 /* A subprogram (something that doesn't return anything) shouldn't
4022 be considered Pure since there would be no reason for such a
4023 subprogram. Note that procedures with Out (or In Out) parameters
4024 have already been converted into a function with a return type. */
4028 /* The semantics of "pure" in Ada essentially matches that of "const"
4029 in the back-end. In particular, both properties are orthogonal to
4030 the "nothrow" property. But this is true only if the EH circuitry
4031 is explicit in the internal representation of the back-end. If we
4032 are to completely hide the EH circuitry from it, we need to declare
4033 that calls to pure Ada subprograms that can throw have side effects
4034 since they can trigger an "abnormal" transfer of control flow; thus
4035 they can be neither "const" nor "pure" in the back-end sense. */
4036 gnu_type
4046 gnu_stub_type
4053 /* If we have a builtin decl for that function, check the signatures
4054 compatibilities. If the signatures are compatible, use the builtin
4055 decl. If they are not, we expect the checker predicate to have
4056 posted the appropriate errors, and just continue with what we have
4057 so far. */
4059 {
4063 {
4067 }
4068 }
4070 /* If there was no specified Interface_Name and the external and
4071 internal names of the subprogram are the same, only use the
4072 internal name to allow disambiguation of nested subprograms. */
4076 /* If we are defining the subprogram and it has an Address clause
4077 we must get the address expression from the saved GCC tree for the
4078 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4079 the address expression here since the front-end has guaranteed
4080 in that case that the elaboration has no effects. If there is
4081 an Address clause and we are not defining the object, just
4082 make it a constant. */
4084 {
4088 gnu_address
4095 /* Convert the type of the object to a reference type that can
4096 alias everything as per 13.3(19). */
4097 gnu_type
4102 gnu_decl
4107 }
4113 else
4114 {
4116 {
4120 }
4126 gnat_entity);
4128 {
4129 tree gnu_stub_decl
4134 gnat_entity);
4136 }
4138 /* This is unrelated to the stub built right above. */
4141 }
4142 }
4153 {
4154 /* Get the "full view" of this entity. If this is an incomplete
4155 entity from a limited with, treat its non-limited view as the
4156 full view. Otherwise, use either the full view or the underlying
4157 full view, whichever is present. This is used in all the tests
4158 below. */
4159 Entity_Id full_view
4167 /* If this is an incomplete type with no full view, it must be a Taft
4168 Amendment type, in which case we return a dummy type. Otherwise,
4169 just get the type from its Etype. */
4171 {
4174 else
4175 {
4179 }
4181 }
4183 /* If we already made a type for the full view, reuse it. */
4185 {
4188 }
4190 /* Otherwise, if we are not defining the type now, get the type
4191 from the full view. But always get the type from the full view
4192 for define on use types, since otherwise we won't see them! */
4198 {
4202 }
4204 /* For incomplete types, make a dummy type entry which will be
4205 replaced later. */
4208 /* Save this type as the full declaration's type so we can do any
4209 needed updates when we see it. */
4215 }
4217 /* Simple class_wide types are always viewed as their root_type
4218 by Gigi unless an Equivalent_Type is specified. */
4230 else
4242 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4243 we've already saved it, so we don't try to. */
4250 }
4252 /* If we had a case where we evaluated another type and it might have
4253 defined this one, handle it here. */
4255 {
4258 }
4260 /* If we are processing a type and there is either no decl for it or
4261 we just made one, do some common processing for the type, such as
4262 handling alignment and possible padding. */
4265 {
4273 /* ??? Don't set the size for a String_Literal since it is either
4274 confirming or we don't handle it properly (if the low bound is
4275 non-constant). */
4281 /* If a size was specified, see if we can make a new type of that size
4282 by rearranging the type, for example from a fat to a thin pointer. */
4284 {
4285 gnu_type
4292 }
4294 /* If the alignment hasn't already been processed and this is
4295 not an unconstrained array, see if an alignment is specified.
4296 If not, we pick a default alignment for atomic objects. */
4298 ;
4300 {
4304 /* Warn on suspiciously large alignments. This should catch
4305 errors about the (alignment,byte)/(size,bit) discrepancy. */
4307 {
4308 tree size;
4310 /* If a size was specified, take it into account. Otherwise
4311 use the RM size for records as the type size has already
4312 been adjusted to the alignment. */
4320 else
4323 /* Consider an alignment as suspicious if the alignment/size
4324 ratio is greater or equal to the byte/bit ratio. */
4329 gnat_entity);
4330 }
4331 }
4342 /* See if we need to pad the type. If we did, and made a record,
4343 the name of the new type may be changed. So get it back for
4344 us when we make the new TYPE_DECL below. */
4351 {
4355 }
4359 /* If we are at global level, GCC will have applied variable_size to
4360 the type, but that won't have done anything. So, if it's not
4361 a constant or self-referential, call elaborate_expression_1 to
4362 make a variable for the size rather than calculating it each time.
4363 Handle both the RM size and the actual size. */
4368 {
4372 {
4379 }
4380 else
4381 {
4388 /* ??? For now, store the size as a multiple of the alignment
4389 in bytes so that we can see the alignment from the tree. */
4391 = build_binary_op
4393 elaborate_expression_1
4404 SET_TYPE_ADA_SIZE
4407 gnat_entity,
4411 }
4412 }
4414 /* If this is a record type or subtype, call elaborate_expression_1 on
4415 any field position. Do this for both global and local types.
4416 Skip any fields that we haven't made trees for to avoid problems with
4417 class wide types. */
4422 {
4425 /* ??? Unfortunately, GCC needs to be able to prove the
4426 alignment of this offset and if it's a variable, it can't.
4427 In GCC 3.4, we'll use DECL_OFFSET_ALIGN in some way, but
4428 right now, we have to put in an explicit multiply and
4429 divide by that value. */
4431 {
4433 = build_binary_op
4435 elaborate_expression_1
4445 /* ??? The context of gnu_field is not necessarily gnu_type so
4446 the MULT_EXPR node built above may not be marked by the call
4447 to create_type_decl below. */
4450 }
4451 }
4455 | (TYPE_QUAL_VOLATILE
4471 else
4473 }
4476 {
4479 /* Back-annotate the Alignment of the type if not already in the
4480 tree. Likewise for sizes. */
4486 {
4487 /* If the size is self-referential, we annotate the maximum
4488 value of that size. */
4497 {
4498 /* In this mode the tag and the parent components are not
4499 generated by the front-end, so the sizes must be adjusted
4500 explicitly now. */
4504 {
4505 size_offset
4509 }
4510 else
4518 }
4519 }
4523 }
4533 /* If we haven't already, associate the ..._DECL node that we just made with
4534 the input GNAT entity node. */
4538 /* If this is an enumeral or floating-point type, we were not able to set
4539 the bounds since they refer to the type. These bounds are always static.
4541 For enumeration types, also write debugging information and declare the
4542 enumeration literal table, if needed. */
4546 {
4549 /* If this is a padded type, we need to use the underlying type. */
4554 /* If this is a floating point type and we haven't set a floating
4555 point type yet, use this in the evaluation of the bounds. */
4565 {
4566 /* Since this has both a typedef and a tag, avoid outputting
4567 the name twice. */
4570 }
4571 }
4573 /* If we deferred processing of incomplete types, re-enable it. If there
4574 were no other disables and we have some to process, do so. */
4576 {
4578 {
4581 /* We are back to level 0 for the deferring of incomplete types.
4582 But processing these incomplete types below may itself require
4583 deferring, so preserve what we have and restart from scratch. */
4587 /* For finalization, however, all types must be complete so we
4588 cannot do the same because deferred incomplete types may end up
4589 referencing each other. Process them all recursively first. */
4590 defer_finalize_level++;
4593 {
4600 }
4602 defer_finalize_level--;
4603 }
4605 /* All the deferred incomplete types have been processed so we can
4606 now proceed with the finalization of the deferred types. */
4608 {
4610 tree t;
4616 }
4617 }
4619 /* If we are not defining this type, see if it's in the incomplete list.
4620 If so, handle that list entry now. */
4622 {
4627 {
4631 }
4632 }
4635 force_global--;
4644 }
4646 /* Similar, but if the returned value is a COMPONENT_REF, return the
4647 FIELD_DECL. */
4649 tree
4651 {
4658 }
4660 /* Wrap up compilation of DECL, a TYPE_DECL, possibly deferring it.
4661 Every TYPE_DECL generated for a type definition must be passed
4662 to this function once everything else has been done for it. */
4664 void
4666 {
4667 /* We need to defer finalizing the type if incomplete types
4668 are being deferred or if they are being processed. */
4671 else
4673 }
4675 /* Same as above but without deferring the compilation. This
4676 function should not be invoked directly on a TYPE_DECL. */
4678 static void
4680 {
4686 /* Now process all the variants. This is needed for STABS. */
4688 {
4693 {
4696 }
4699 }
4700 }
4702 /* Finalize any From_With_Type incomplete types. We do this after processing
4703 our compilation unit and after processing its spec, if this is a body. */
4705 void
4707 {
4713 {
4720 }
4721 }
4723 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
4724 kind of type (such E_Task_Type) that has a different type which Gigi
4725 uses for its representation. If the type does not have a special type
4726 for its representation, return GNAT_ENTITY. If a type is supposed to
4727 exist, but does not, abort unless annotating types, in which case
4728 return Empty. If GNAT_ENTITY is Empty, return Empty. */
4730 Entity_Id
4732 {
4739 {
4765 }
4769 }
4771 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
4772 using MECH as its passing mechanism, to be placed in the parameter
4773 list built for GNAT_SUBPROG. Assume a foreign convention for the
4774 latter if FOREIGN is true. Also set CICO to true if the parameter
4775 must use the copy-in copy-out implementation mechanism.
4777 The returned tree is a PARM_DECL, except for those cases where no
4778 parameter needs to be actually passed to the subprogram; the type
4779 of this "shadow" parameter is then returned instead. */
4781 static tree
4784 {
4789 /* The parameter can be indirectly modified if its address is taken. */
4792 tree gnu_param;
4794 /* Copy-return is used only for the first parameter of a valued procedure.
4795 It's a copy mechanism for which a parameter is never allocated. */
4797 {
4801 }
4803 /* If this is either a foreign function or if the underlying type won't
4804 be passed by reference, strip off possible padding type. */
4807 {
4811 || foreign
4815 }
4817 /* If this is a read-only parameter, make a variant of the type that is
4818 read-only. ??? However, if this is an unconstrained array, that type
4819 can be very complex, so skip it for now. Likewise for any other
4820 self-referential type. */
4828 /* For foreign conventions, pass arrays as pointers to the element type.
4829 First check for unconstrained array and get the underlying array. */
4831 gnu_param_type
4834 /* VMS descriptors are themselves passed by reference.
4835 Build both a 32bit and 64bit descriptor, one of which will be chosen
4836 in fill_vms_descriptor. */
4838 {
4839 gnu_param_type_alt
4842 gnat_subprog));
4843 gnu_param_type
4846 gnat_subprog));
4847 }
4849 {
4852 gnu_param_type
4855 gnat_subprog));
4856 }
4858 /* Arrays are passed as pointers to element type for foreign conventions. */
4862 {
4863 /* Strip off any multi-dimensional entries, then strip
4864 off the last array to get the component type. */
4878 }
4880 /* Fat pointers are passed as thin pointers for foreign conventions. */
4882 gnu_param_type
4885 /* If we must pass or were requested to pass by reference, do so.
4886 If we were requested to pass by copy, do so.
4887 Otherwise, for foreign conventions, pass In Out or Out parameters
4888 or aggregates by reference. For COBOL and Fortran, pass all
4889 integer and FP types that way too. For Convention Ada, use
4890 the standard Ada default. */
4894 && ((foreign
4896 || (foreign
4901 || (!foreign
4903 {
4906 }
4908 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
4915 /* If this is an Out parameter that isn't passed by reference and isn't
4916 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
4917 it will be a VAR_DECL created when we process the procedure, so just
4918 return its type. For the special parameter of a valued procedure,
4919 never pass it in.
4921 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
4922 Out parameters with discriminants or implicit initial values to be
4923 handled like In Out parameters. These type are normally built as
4924 aggregates, hence passed by reference, except for some packed arrays
4925 which end up encoded in special integer types.
4927 The exception we need to make is then for packed arrays of records
4928 with discriminants or implicit initial values. We have no light/easy
4929 way to check for the latter case, so we merely check for packed arrays
4930 of records. This may lead to useless copy-in operations, but in very
4931 rare cases only, as these would be exceptions in a set of already
4932 exceptional situations. */
4934 && !by_ref
4935 && (by_return
4954 /* Save the alternate descriptor for later. */
4957 /* If no Mechanism was specified, indicate what we're using, then
4958 back-annotate it. */
4964 }
4966 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
4968 static bool
4970 {
4977 return
4979 }
4981 /* Return true if the array type specified by GNAT_TYPE and GNU_TYPE has
4982 a non-aliased component in the back-end sense. */
4984 static bool
4986 {
4987 /* If the type below this is a multi-array type, then
4988 this does not have aliased components. */
4997 }
4998 \f
4999 /* Given GNAT_ENTITY, elaborate all expressions that are required to
5000 be elaborated at the point of its definition, but do nothing else. */
5002 void
5004 {
5006 {
5013 {
5017 /* ??? Tests for avoiding static constraint error expression
5018 is needed until the front stops generating bogus conversions
5019 on bounds of real types. */
5028 }
5031 {
5035 /* If this is a record extension, go a level further to find the
5036 record definition. */
5039 }
5049 {
5050 Node_Id gnat_discriminant_expr;
5051 Entity_Id gnat_field;
5054 gnat_discriminant_expr
5059 /* ??? For now, ignore access discriminants. */
5062 gnat_entity,
5064 }
5067 }
5068 }
5069 \f
5070 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
5071 any entities on its entity chain similarly. */
5073 void
5075 {
5076 Entity_Id gnat_sub_entity;
5079 /* If this has an entity list, process all in the list. */
5096 /* Now clear this if it has been defined, but only do so if it isn't
5097 a subprogram or parameter. We could refine this, but it isn't
5098 worth it. If this is statically allocated, it is supposed to
5099 hang around out of cope. */
5102 {
5105 }
5106 }
5107 \f
5108 /* Set the alias set of GNU_NEW_TYPE to be that of GNU_OLD_TYPE. If this
5109 is a multi-dimensional array type, do this recursively. */
5111 static void
5113 {
5114 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
5115 of a one-dimensional array, since the padding has the same alias set
5116 as the field type, but if it's a multi-dimensional array, we need to
5117 see the inner types. */
5123 /* We need to be careful here in case GNU_OLD_TYPE is an unconstrained
5124 array. In that case, it doesn't have the same shape as GNU_NEW_TYPE,
5125 so we need to go down to what does. */
5127 gnu_old_type
5137 }
5138 \f
5139 /* Return a TREE_LIST describing the substitutions needed to reflect
5140 discriminant substitutions from GNAT_SUBTYPE to GNAT_TYPE and add
5141 them to GNU_LIST. If GNAT_TYPE is not specified, use the base type
5142 of GNAT_SUBTYPE. The substitutions can be in any order. TREE_PURPOSE
5143 gives the tree for the discriminant and TREE_VALUES is the replacement
5144 value. They are in the form of operands to substitute_in_expr.
5145 DEFINITION is as in gnat_to_gnu_entity. */
5147 static tree
5150 {
5151 Entity_Id gnat_discrim;
5152 Node_Id gnat_value;
5163 /* Ignore access discriminants. */
5166 elaborate_expression
5170 gnu_list);
5173 }
5174 \f
5175 /* Return true if the size represented by GNU_SIZE can be handled by an
5176 allocation. If STATIC_P is true, consider only what can be done with a
5177 static allocation. */
5179 static bool
5181 {
5182 HOST_WIDE_INT our_size;
5184 /* If this is not a static allocation, the only case we want to forbid
5185 is an overflowing size. That will be converted into a raise a
5186 Storage_Error. */
5191 /* Otherwise, we need to deal with both variable sizes and constant
5192 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
5193 since assemblers may not like very large sizes. */
5199 }
5200 \f
5201 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
5202 NAME, ARGS and ERROR_POINT. */
5204 static void
5207 tree attr_name,
5208 tree attr_args,
5209 Node_Id attr_error_point)
5210 {
5220 }
5222 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
5224 static void
5226 {
5227 Node_Id gnat_temp;
5232 {
5241 {
5243 (gnat_to_gnu
5250 (gnat_to_gnu
5251 (Expression
5254 }
5257 {
5284 }
5287 /* Prepend to the list now. Make a list of the argument we might
5288 have, as GCC expects it. */
5289 prepend_one_attribute_to
5296 }
5297 }
5298 \f
5299 /* Get the unpadded version of a GNAT type. */
5301 tree
5303 {
5310 }
5311 \f
5312 /* Called when we need to protect a variable object using a save_expr. */
5314 tree
5316 {
5323 {
5331 }
5332 else
5334 }
5335 \f
5336 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
5337 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
5338 return the GCC tree to use for that expression. GNU_NAME is the
5339 qualification to use if an external name is appropriate and DEFINITION is
5340 nonzero if this is a definition of GNAT_ENTITY. If NEED_VALUE is nonzero,
5341 we need a result. Otherwise, we are just elaborating this for
5342 side-effects. If NEED_DEBUG is nonzero we need the symbol for debugging
5343 purposes even if it isn't needed for code generation. */
5345 static tree
5349 {
5350 tree gnu_expr;
5352 /* If we already elaborated this expression (e.g., it was involved
5353 in the definition of a private type), use the old value. */
5357 /* If we don't need a value and this is static or a discriminant, we
5358 don't need to do anything. */
5365 /* Otherwise, convert this tree to its GCC equivalent. */
5366 gnu_expr
5370 /* Save the expression in case we try to elaborate this entity again. Since
5371 this is not a DECL, don't check it. Don't save if it's a discriminant. */
5376 }
5378 /* Similar, but take a GNU expression. */
5380 static tree
5384 {
5386 /* Skip any conversions and simple arithmetics to see if the expression
5387 is a read-only variable.
5388 ??? This really should remain read-only, but we have to think about
5389 the typing of the tree here. */
5390 tree gnu_inner_expr
5395 /* In most cases, we won't see a naked FIELD_DECL here because a
5396 discriminant reference will have been replaced with a COMPONENT_REF
5397 when the type is being elaborated. However, there are some cases
5398 involving child types where we will. So convert it to a COMPONENT_REF
5399 here. We have to hope it will be at the highest level of the
5400 expression in these cases. */
5406 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
5407 that is read-only, make a variable that is initialized to contain the
5408 bound when the package containing the definition is elaborated. If
5409 this entity is defined at top level and a bound or discriminant value
5410 isn't a constant or a reference to a discriminant, replace the bound
5411 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
5412 rely here on the fact that an expression cannot contain both the
5413 discriminant and some other variable. */
5421 /* If this is a static expression or contains a discriminant, we don't
5422 need the variable for debugging (and can't elaborate anyway if a
5423 discriminant). */
5429 /* Now create the variable if we need it. */
5431 gnu_decl
5438 /* We only need to use this variable if we are in global context since GCC
5439 can do the right thing in the local case. */
5444 else
5446 }
5447 \f
5448 /* Create a record type that contains a SIZE bytes long field of TYPE with a
5449 starting bit position so that it is aligned to ALIGN bits, and leaving at
5450 least ROOM bytes free before the field. BASE_ALIGN is the alignment the
5451 record is guaranteed to get. */
5453 tree
5456 {
5457 /* We will be crafting a record type with one field at a position set to be
5458 the next multiple of ALIGN past record'address + room bytes. We use a
5459 record placeholder to express record'address. */
5464 tree record_addr_st
5467 /* The diagram below summarizes the shape of what we manipulate:
5469 <--------- pos ---------->
5470 { +------------+-------------+-----------------+
5471 record =>{ |############| ... | field (type) |
5472 { +------------+-------------+-----------------+
5473 |<-- room -->|<- voffset ->|<---- size ----->|
5474 o o
5475 | |
5476 record_addr vblock_addr
5478 Every length is in sizetype bytes there, except "pos" which has to be
5479 set as a bit position in the GCC tree for the record. */
5492 /* Compute VOFFSET and then POS. The next byte position multiple of some
5493 alignment after some address is obtained by "and"ing the alignment minus
5494 1 with the two's complement of the address. */
5500 /* POS = (ROOM + VOFFSET) * BIT_PER_UNIT, in bitsizetype. */
5505 bitsize_unit_node);
5507 /* Craft the GCC record representation. We exceptionally do everything
5508 manually here because 1) our generic circuitry is not quite ready to
5509 handle the complex position/size expressions we are setting up, 2) we
5510 have a strong simplifying factor at hand: we know the maximum possible
5511 value of voffset, and 3) we have to set/reset at least the sizes in
5512 accordance with this maximum value anyway, as we need them to convey
5513 what should be "alloc"ated for this type.
5515 Use -1 as the 'addressable' indication for the field to prevent the
5516 creation of a bitfield. We don't need one, it would have damaging
5517 consequences on the alignment computation, and create_field_decl would
5518 make one without this special argument, for instance because of the
5519 complex position expression. */
5531 bitsize_unit_node),
5541 }
5542 \f
5543 /* Return the result of rounding T up to ALIGN. */
5547 {
5552 }
5554 /* TYPE is a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE that is being used
5555 as the field type of a packed record if IN_RECORD is true, or as the
5556 component type of a packed array if IN_RECORD is false. See if we can
5557 rewrite it either as a type that has a non-BLKmode, which we can pack
5558 tighter in the packed record case, or as a smaller type with BLKmode.
5559 If so, return the new type. If not, return the original type. */
5561 static tree
5563 {
5568 /* No point in doing anything if the size is zero. */
5574 /* Copy the name and flags from the old type to that of the new.
5575 Note that we rely on the pointer equality created here for
5576 TYPE_NAME to look through conversions in various places. */
5583 /* If we are in a record and have a small size, set the alignment to
5584 try for an integral mode. Otherwise set it to try for a smaller
5585 type with BLKmode. */
5587 {
5590 }
5591 else
5592 {
5595 /* Do not try to shrink the size if the RM size is not constant. */
5600 /* Round the RM size up to a unit boundary to get the minimal size
5601 for a BLKmode record. Give up if it's already the size. */
5609 }
5613 /* Now copy the fields, keeping the position and size as we don't want
5614 to change the layout by propagating the packedness downwards. */
5617 {
5628 /* However, for the last field in a not already packed record type
5629 that is of an aggregate type, we need to use the RM_Size in the
5630 packable version of the record type, see finish_record_type. */
5640 else
5649 SET_DECL_ORIGINAL_FIELD
5658 }
5663 /* If this is a padding record, we never want to make the size smaller
5664 than what was specified. For QUAL_UNION_TYPE, also copy the size. */
5667 {
5670 }
5671 else
5672 {
5676 }
5683 /* Try harder to get a packable type if necessary, for example
5684 in case the record itself contains a BLKmode field. */
5689 /* If neither the mode nor the size has shrunk, return the old type. */
5694 }
5695 \f
5696 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
5697 if needed. We have already verified that SIZE and TYPE are large enough.
5699 GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
5700 to issue a warning.
5702 IS_USER_TYPE is true if we must complete the original type.
5704 DEFINITION is true if this type is being defined.
5706 SAME_RM_SIZE is true if the RM_Size of the resulting type is to be set
5707 to SIZE too; otherwise, it's set to the RM_Size of the original type. */
5709 tree
5713 {
5719 /* If TYPE is a padded type, see if it agrees with any size and alignment
5720 we were given. If so, return the original type. Otherwise, strip
5721 off the padding, since we will either be returning the inner type
5722 or repadding it. If no size or alignment is specified, use that of
5723 the original padded type. */
5725 {
5742 }
5744 /* If the size is either not being changed or is being made smaller (which
5745 is not done here (and is only valid for bitfields anyway), show the size
5746 isn't changing. Likewise, clear the alignment if it isn't being
5747 changed. Then return if we aren't doing anything. */
5760 /* If requested, complete the original type and give it a name. */
5767 gnat_entity);
5769 /* We used to modify the record in place in some cases, but that could
5770 generate incorrect debugging information. So make a new record
5771 type and name. */
5789 bitsize_unit_node));
5791 /* If we are changing the alignment and the input type is a record with
5792 BLKmode and a small constant size, try to make a form that has an
5793 integral mode. This might allow the padding record to also have an
5794 integral mode, which will be much more efficient. There is no point
5795 in doing so if a size is specified unless it is also a small constant
5796 size and it is incorrect to do so if we cannot guarantee that the mode
5797 will be naturally aligned since the field must always be addressable.
5799 ??? This might not always be a win when done for a stand-alone object:
5800 since the nominal and the effective type of the object will now have
5801 different modes, a VIEW_CONVERT_EXPR will be required for converting
5802 between them and it might be hard to overcome afterwards, including
5803 at the RTL level when the stand-alone object is accessed as a whole. */
5810 && (!size
5813 {
5818 }
5820 /* Now create the field with the original size. */
5825 /* Do not finalize it until after the auxiliary record is built. */
5828 /* Set the same size for its RM_size if requested; otherwise reuse
5829 the RM_size of the original type. */
5832 /* Unless debugging information isn't being written for the input type,
5833 write a record that shows what we are a subtype of and also make a
5834 variable that indicates our size, if still variable. */
5840 {
5864 }
5868 /* If the size was widened explicitly, maybe give a warning. Take the
5869 original size as the maximum size of the input if there was an
5870 unconstrained record involved and round it up to the specified alignment,
5871 if one was specified. */
5883 {
5896 /* Generate message only for entities that come from source, since
5897 if we have an entity created by expansion, the message will be
5898 generated for some other corresponding source entity. */
5901 gnat_entity,
5908 }
5911 }
5912 \f
5913 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
5914 the value passed against the list of choices. */
5916 tree
5918 {
5919 Node_Id choice;
5920 Node_Id gnat_temp;
5925 {
5927 {
5932 /* There's no good type to use here, so we might as well use
5933 integer_type_node. */
5934 this_test
5948 this_test
5958 /* This represents either a subtype range, an enumeration
5959 literal, or a constant Ekind says which. If an enumeration
5960 literal or constant, fall through to the next case. */
5963 {
5969 this_test
5976 }
5977 /* ... fall through ... */
5982 single);
5991 }
5995 }
5998 }
5999 \f
6000 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
6001 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
6003 static int
6005 {
6006 /* If the field contains an item of variable size, we cannot pack it
6007 because we cannot create temporaries of non-fixed size in case
6008 we need to take the address of the field. See addressable_p and
6009 the notes on the addressability issues for further details. */
6013 /* If the alignment of the record is specified and the field type
6014 is over-aligned, request Storage_Unit alignment for the field. */
6016 {
6019 else
6021 }
6024 }
6026 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
6027 placed in GNU_RECORD_TYPE.
6029 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
6030 record has Component_Alignment of Storage_Unit, -2 if the enclosing
6031 record has a specified alignment.
6033 DEFINITION is true if this field is for a record being defined. */
6035 static tree
6038 {
6042 bool needs_strict_alignment
6046 /* If this field requires strict alignment, we cannot pack it because
6047 it would very likely be under-aligned in the record. */
6050 else
6053 /* If a size is specified, use it. Otherwise, if the record type is packed,
6054 use the official RM size. See "Handling of Type'Size Values" in Einfo
6055 for further details. */
6062 else
6065 /* If we have a specified size that's smaller than that of the field type,
6066 or a position is specified, and the field type is also a record that's
6067 BLKmode, see if we can get either an integral mode form of the type or
6068 a smaller BLKmode form. If we can, show a size was specified for the
6069 field if there wasn't one already, so we know to make this a bitfield
6070 and avoid making things wider.
6072 Doing this is first useful if the record is packed because we may then
6073 place the field at a non-byte-aligned position and so achieve tighter
6074 packing.
6076 This is in addition *required* if the field shares a byte with another
6077 field and the front-end lets the back-end handle the references, because
6078 GCC does not handle BLKmode bitfields properly.
6080 We avoid the transformation if it is not required or potentially useful,
6081 as it might entail an increase of the field's alignment and have ripple
6082 effects on the outer record type. A typical case is a field known to be
6083 byte aligned and not to share a byte with another field.
6085 Besides, we don't even look the possibility of a transformation in cases
6086 known to be in error already, for instance when an invalid size results
6087 from a component clause. */
6093 || (gnu_size
6096 {
6097 /* See what the alternate type and size would be. */
6100 bool has_byte_aligned_clause
6105 /* Compute whether we should avoid the substitution. */
6106 bool reject
6107 /* There is no point substituting if there is no change... */
6109 /* ... nor when the field is known to be byte aligned and not to
6110 share a byte with another field. */
6111 || (has_byte_aligned_clause
6113 /* The size of an aliased field must be an exact multiple of the
6114 type's alignment, which the substitution might increase. Reject
6115 substitutions that would so invalidate a component clause when the
6116 specified position is byte aligned, as the change would have no
6117 real benefit from the packing standpoint anyway. */
6119 && has_byte_aligned_clause
6122 /* Substitute unless told otherwise. */
6124 {
6129 }
6130 }
6132 /* If we are packing the record and the field is BLKmode, round the
6133 size up to a byte boundary. */
6138 {
6143 /* Ensure the position does not overlap with the parent subtype,
6144 if there is one. */
6146 {
6147 tree gnu_parent
6153 {
6154 post_error_ne_tree
6158 }
6159 }
6161 /* If this field needs strict alignment, ensure the record is
6162 sufficiently aligned and that that position and size are
6163 consistent with the alignment. */
6165 {
6171 {
6173 post_error_ne_tree
6179 post_error_ne_tree
6185 post_error_ne_tree
6191 }
6196 {
6198 post_error_ne_num
6204 post_error_ne_num
6210 post_error_ne_num
6215 else
6219 }
6220 }
6224 }
6226 /* If the record has rep clauses and this is the tag field, make a rep
6227 clause for it as well. */
6230 {
6233 }
6235 else
6238 /* We need to make the size the maximum for the type if it is
6239 self-referential and an unconstrained type. In that case, we can't
6240 pack the field since we can't make a copy to align it. */
6242 && !gnu_size
6245 {
6248 }
6250 /* If a size is specified, adjust the field's type to it. */
6252 {
6253 /* If the field's type is justified modular, we would need to remove
6254 the wrapper to (better) meet the layout requirements. However we
6255 can do so only if the field is not aliased to preserve the unique
6256 layout and if the prescribed size is not greater than that of the
6257 packed array to preserve the justification. */
6265 gnu_field_type
6270 }
6272 /* Otherwise (or if there was an error), don't specify a position. */
6273 else
6279 /* Now create the decl for the field. */
6291 }
6292 \f
6293 /* Return true if TYPE is a type with variable size, a padding type with a
6294 field of variable size or is a record that has a field such a field. */
6296 static bool
6298 {
6299 tree field;
6319 }
6320 \f
6321 /* qsort comparer for the bit positions of two record components. */
6323 static int
6325 {
6328 const int ret
6332 }
6334 /* Return a GCC tree for a record type given a GNAT Component_List and a chain
6335 of GCC trees for fields that are in the record and have already been
6336 processed. When called from gnat_to_gnu_entity during the processing of a
6337 record type definition, the GCC nodes for the discriminants will be on
6338 the chain. The other calls to this function are recursive calls from
6339 itself for the Component_List of a variant and the chain is empty.
6341 PACKED is 1 if this is for a packed record, -1 if this is for a record
6342 with Component_Alignment of Storage_Unit, -2 if this is for a record
6343 with a specified alignment.
6345 DEFINITION is true if we are defining this record.
6347 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
6348 with a rep clause is to be added. If it is nonzero, that is all that
6349 should be done with such fields.
6351 CANCEL_ALIGNMENT, if true, means the alignment should be zeroed before
6352 laying out the record. This means the alignment only serves to force fields
6353 to be bitfields, but not require the record to be that aligned. This is
6354 used for variants.
6356 ALL_REP, if true, means a rep clause was found for all the fields. This
6357 simplifies the logic since we know we're not in the mixed case.
6359 DO_NOT_FINALIZE, if true, means that the record type is expected to be
6360 modified afterwards so it will not be sent to the back-end for finalization.
6362 UNCHECKED_UNION, if true, means that we are building a type for a record
6363 with a Pragma Unchecked_Union.
6365 The processing of the component list fills in the chain with all of the
6366 fields of the record and then the record type is finished. */
6368 static void
6373 {
6374 Node_Id component_decl;
6375 Entity_Id gnat_field;
6376 Node_Id variant_part;
6382 /* For each variable within each component declaration create a GCC field
6383 and add it to the list, skipping any pragmas in the list. */
6388 {
6393 else
6394 {
6398 /* If this is the _Tag field, put it before any discriminants,
6399 instead of after them as is the case for all other fields.
6400 Ignore field of void type if only annotating. */
6403 else
6404 {
6407 }
6408 }
6411 }
6413 /* At the end of the component list there may be a variant part. */
6416 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
6417 mutually exclusive and should go in the same memory. To do this we need
6418 to treat each variant as a record whose elements are created from the
6419 component list for the variant. So here we create the records from the
6420 lists for the variants and put them all into the QUAL_UNION_TYPE.
6421 If this is an Unchecked_Union, we make a UNION_TYPE instead or
6422 use GNU_RECORD_TYPE if there are no fields so far. */
6424 {
6426 Node_Id variant;
6428 tree gnu_var_name
6432 tree gnu_union_type;
6433 tree gnu_union_name;
6434 tree gnu_union_field;
6443 /* Reuse an enclosing union if all fields are in the variant part
6444 and there is no representation clause on the record, to match
6445 the layout of C unions. There is an associated check below. */
6450 else
6451 {
6452 gnu_union_type
6458 }
6463 {
6465 tree gnu_inner_name;
6466 tree gnu_qual;
6474 /* Set the alignment of the inner type in case we need to make
6475 inner objects into bitfields, but then clear it out
6476 so the record actually gets only the alignment required. */
6480 /* Similarly, if the outer record has a size specified and all fields
6481 have record rep clauses, we can propagate the size into the
6482 variant part. */
6484 {
6488 }
6490 /* Create the record type for the variant. Note that we defer
6491 finalizing it until after we are sure to actually use it. */
6502 /* If this is an Unchecked_Union and we have exactly one field,
6503 use this field directly to match the layout of C unions. */
6508 else
6509 {
6510 /* Deal with packedness like in gnat_to_gnu_field. */
6511 int field_packed
6514 /* Finalize the record type now. We used to throw away
6515 empty records but we no longer do that because we need
6516 them to generate complete debug info for the variant;
6517 otherwise, the union type definition will be lacking
6518 the fields associated with these empty variants. */
6523 (all_rep_and_size
6526 (all_rep_and_size
6534 }
6538 }
6540 /* Only make the QUAL_UNION_TYPE if there are any non-empty variants. */
6542 {
6546 {
6550 }
6555 /* If GNU_UNION_TYPE is our record type, it means we must have an
6556 Unchecked_Union with no fields. Verify that and, if so, just
6557 return. */
6559 {
6561 && !gnu_field_list
6564 }
6566 /* Deal with packedness like in gnat_to_gnu_field. */
6567 union_field_packed
6570 gnu_union_field
6572 union_field_packed,
6579 }
6580 }
6582 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
6583 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do this
6584 in a separate pass since we want to handle the discriminants but can't
6585 play with them until we've used them in debugging data above.
6587 ??? Note: if we then reorder them, debugging information will be wrong,
6588 but there's nothing that can be done about this at the moment. */
6590 {
6592 {
6597 else
6603 }
6604 else
6605 {
6608 }
6609 }
6611 /* If we have any items in our rep'ed field list, it is not the case that all
6612 the fields in the record have rep clauses, and P_REP_LIST is nonzero,
6613 set it and ignore the items. */
6617 {
6618 /* Otherwise, sort the fields by bit position and put them into their
6619 own record if we have any fields without rep clauses. */
6620 tree gnu_rep_type
6632 /* Put the fields in the list in order of increasing position, which
6633 means we start from the end. */
6636 {
6640 }
6643 {
6649 }
6650 else
6651 {
6654 }
6655 }
6662 }
6663 \f
6664 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
6665 placed into an Esize, Component_Bit_Offset, or Component_Size value
6666 in the GNAT tree. */
6668 static Uint
6670 {
6672 TCode tcode;
6678 /* See if we've already saved the value for this node. */
6680 {
6691 }
6693 /* If we do not return inside this switch, TCODE will be set to the
6694 code to use for a Create_Node operand and LEN (set above) will be
6695 the number of recursive calls for us to make. */
6698 {
6703 /* This may have come from a conversion from some smaller type,
6704 so ensure this is in bitsizetype. */
6707 /* For negative values, use NEGATE_EXPR of the supplied value. */
6709 {
6710 /* The ridiculous code below is to handle the case of the largest
6711 negative integer. */
6714 tree temp;
6717 {
6718 negative_size
6721 bitsize_one_node));
6723 }
6730 }
6737 /* This peculiar test is to make sure that the size fits in an int
6738 on machines where HOST_WIDE_INT is not "int". */
6741 else
6745 /* The only case we handle here is a simple discriminant reference. */
6753 else
6759 /* Now just list the operations we handle. */
6791 }
6793 /* Now get each of the operands that's relevant for this code. If any
6794 cannot be expressed as a repinfo node, say we can't. */
6799 {
6803 }
6807 /* Save the result in the cache. */
6809 {
6813 }
6816 }
6818 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding
6819 GCC type, set Component_Bit_Offset and Esize to the position and size
6820 used by Gigi. */
6822 static void
6824 {
6825 tree gnu_list;
6826 tree gnu_entry;
6827 Entity_Id gnat_field;
6829 /* We operate by first making a list of all fields and their positions
6830 (we can get the sizes easily at any time) by a recursive call
6831 and then update all the sizes into the tree. */
6834 BIGGEST_ALIGNMENT);
6841 {
6845 gnu_list);
6848 {
6850 {
6851 /* In this mode the tag and parent components have not been
6852 generated, so we add the appropriate offset to each
6853 component. For a component appearing in the current
6854 extension, the offset is the size of the parent. */
6857 parent_offset
6859 bitsizetype);
6860 else
6862 }
6864 Set_Component_Bit_Offset
6866 annotate_value
6871 parent_offset)));
6875 }
6878 {
6879 /* If there is no gnu_entry, this is an inherited component whose
6880 position is the same as in the parent type. */
6881 Set_Component_Bit_Offset
6886 }
6887 }
6888 }
6890 /* Scan all fields in GNU_TYPE and build entries where TREE_PURPOSE is the
6891 FIELD_DECL and TREE_VALUE a TREE_LIST with TREE_PURPOSE being the byte
6892 position and TREE_VALUE being a TREE_LIST with TREE_PURPOSE the value to be
6893 placed into DECL_OFFSET_ALIGN and TREE_VALUE the bit position. GNU_POS is
6894 to be added to the position, GNU_BITPOS to the bit position, OFFSET_ALIGN is
6895 the present value of DECL_OFFSET_ALIGN and GNU_LIST is a list of the entries
6896 so far. */
6898 static tree
6901 {
6902 tree gnu_field;
6907 {
6912 unsigned int our_offset_align
6915 gnu_result
6920 NULL_TREE),
6921 gnu_result);
6924 gnu_result
6927 our_offset_align);
6928 }
6931 }
6932 \f
6933 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
6934 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
6935 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
6936 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
6937 for the size of a field. COMPONENT_P is true if we are being called
6938 to process the Component_Size of GNAT_OBJECT. This is used for error
6939 message handling and to indicate to use the object size of GNU_TYPE.
6940 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
6941 it means that a size of zero should be treated as an unspecified size. */
6943 static tree
6946 {
6947 Node_Id gnat_error_node;
6951 /* If a type needs strict alignment, a component of this type in
6952 a packed record cannot be packed and thus uses the type size. */
6955 else
6958 /* Find the node to use for errors. */
6965 else
6968 /* Return 0 if no size was specified, either because Esize was not Present or
6969 the specified size was zero. */
6973 /* Get the size as a tree. Give an error if a size was specified, but cannot
6974 be represented as in sizetype. */
6977 {
6982 }
6984 /* Ignore a negative size since that corresponds to our back-annotation.
6985 Also ignore a zero size unless a size clause exists. */
6989 /* The size of objects is always a multiple of a byte. */
6992 {
6996 else
7000 }
7002 /* If this is an integral type or a packed array type, the front-end has
7003 verified the size, so we need not do it here (which would entail
7004 checking against the bounds). However, if this is an aliased object, it
7005 may not be smaller than the type of the object. */
7010 /* If the object is a record that contains a template, add the size of
7011 the template to the specified size. */
7016 /* Modify the size of the type to be that of the maximum size if it has a
7017 discriminant. */
7021 /* If this is an access type or a fat pointer, the minimum size is that given
7022 by the smallest integral mode that's valid for pointers. */
7024 {
7030 ;
7033 }
7035 /* If the size of the object is a constant, the new size must not be
7036 smaller. */
7040 {
7042 post_error_ne_tree
7045 else
7052 post_error_ne_tree_2
7062 }
7065 }
7066 \f
7067 /* Similarly, but both validate and process a value of RM_Size. This
7068 routine is only called for types. */
7070 static void
7072 {
7073 /* Only give an error if a Value_Size clause was explicitly given.
7074 Otherwise, we'd be duplicating an error on the Size clause. */
7075 Node_Id gnat_attr_node
7078 tree size;
7080 /* Get the size as a tree. Do nothing if none was specified, either
7081 because RM_Size was not Present or if the specified size was zero.
7082 Give an error if a size was specified, but cannot be represented as
7083 in sizetype. */
7089 {
7092 gnat_entity);
7095 }
7097 /* Ignore a negative size since that corresponds to our back-annotation.
7098 Also ignore a zero size unless a size clause exists, a Value_Size
7099 clause exists, or this is an integer type, in which case the
7100 front end will have always set it. */
7107 /* If the old size is self-referential, get the maximum size. */
7111 /* If the size of the object is a constant, the new size must not be
7112 smaller (the front end checks this for scalar types). */
7117 {
7119 post_error_ne_tree
7124 }
7126 /* Otherwise, set the RM_Size. */
7138 }
7139 \f
7140 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
7141 If TYPE is the best type, return it. Otherwise, make a new type. We
7142 only support new integral and pointer types. FOR_BIASED is nonzero if
7143 we are making a biased type. */
7145 static tree
7147 {
7150 tree new_type;
7152 /* If size indicates an error, just return TYPE to avoid propagating
7153 the error. Likewise if it's too large to represent. */
7160 {
7175 /* Only do something if the type is not a packed array type and
7176 doesn't already have the proper size. */
7187 else
7199 else
7204 /* Do something if this is a fat pointer, in which case we
7205 may need to return the thin pointer. */
7207 {
7211 return
7212 build_pointer_type_for_mode
7215 }
7219 /* Only do something if this is a thin pointer, in which case we
7220 may need to return the fat pointer. */
7222 return
7228 }
7231 }
7232 \f
7233 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
7234 a type or object whose present alignment is ALIGN. If this alignment is
7235 valid, return it. Otherwise, give an error and return ALIGN. */
7237 static unsigned int
7239 {
7242 Node_Id gnat_error_node;
7244 /* Don't worry about checking alignment if alignment was not specified
7245 by the source program and we already posted an error for this entity. */
7249 /* Post the error on the alignment clause if any. */
7252 else
7255 /* Within GCC, an alignment is an integer, so we must make sure a value is
7256 specified that fits in that range. Also, there is an upper bound to
7257 alignments we can support/allow. */
7268 else
7269 {
7273 }
7276 }
7278 /* Return the smallest alignment not less than SIZE. */
7280 static unsigned int
7282 {
7284 }
7285 \f
7286 /* Verify that OBJECT, a type or decl, is something we can implement
7287 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
7288 if we require atomic components. */
7290 static void
7292 {
7294 Node_Id gnat_node;
7297 tree size;
7299 /* There are three case of what OBJECT can be. It can be a type, in which
7300 case we take the size, alignment and mode from the type. It can be a
7301 declaration that was indirect, in which case the relevant values are
7302 that of the type being pointed to, or it can be a normal declaration,
7303 in which case the values are of the decl. The code below assumes that
7304 OBJECT is either a type or a decl. */
7306 {
7310 }
7312 {
7316 }
7317 else
7318 {
7322 }
7324 /* Consider all floating-point types atomic and any types that that are
7325 represented by integers no wider than a machine word. */
7332 /* For the moment, also allow anything that has an alignment equal
7333 to its size and which is smaller than a word. */
7341 {
7350 }
7355 else
7358 }
7359 \f
7360 /* Check if FTYPE1 and FTYPE2, two potentially different function type nodes,
7361 have compatible signatures so that a call using one type may be safely
7362 issued if the actual target function type is the other. Return 1 if it is
7363 the case, 0 otherwise, and post errors on the incompatibilities.
7365 This is used when an Ada subprogram is mapped onto a GCC builtin, to ensure
7366 that calls to the subprogram will have arguments suitable for the later
7367 underlying builtin expansion. */
7369 static int
7371 {
7372 /* As of now, we only perform very trivial tests and consider it's the
7373 programmer's responsibility to ensure the type correctness in the Ada
7374 declaration, as in the regular Import cases.
7376 Mismatches typically result in either error messages from the builtin
7377 expander, internal compiler errors, or in a real call sequence. This
7378 should be refined to issue diagnostics helping error detection and
7379 correction. */
7381 /* Almost fake test, ensuring a use of each argument. */
7386 }
7387 \f
7388 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new
7389 type with all size expressions that contain F updated by replacing F
7390 with R. If F is NULL_TREE, always make a new RECORD_TYPE, even if
7391 nothing has changed. */
7393 tree
7395 {
7397 tree tem;
7400 {
7406 {
7415 SET_TYPE_INDEX_TYPE
7418 }
7425 {
7439 }
7453 /* Don't know how to do these yet. */
7457 {
7472 /* If we had bounded the sizes of T by a constant, bound the sizes of
7473 NEW by the same constant. */
7483 }
7488 {
7489 tree field;
7490 bool changed_field
7497 /* Start out with no fields, make new fields, and chain them
7498 in. If we haven't actually changed the type of any field,
7499 discard everything we've done and return the old type. */
7505 {
7516 /* If this is an internal field and the type of this field is
7517 a UNION_TYPE or RECORD_TYPE with no elements, ignore it. If
7518 the type just has one element, treat that as the field.
7519 But don't do this if we are processing a QUAL_UNION_TYPE. */
7524 {
7529 {
7530 tree next_new_field
7533 /* Make sure omitting the union doesn't change
7534 the layout. */
7537 }
7538 }
7545 /* If the size of the old field was set at a constant,
7546 propagate the size in case the type's size was variable.
7547 (This occurs in the case of a variant or discriminated
7548 record with a default size used as a field of another
7549 record.) */
7558 {
7564 /* Do the substitution inside the qualifier and if we find
7565 that this field will not be present, omit it. */
7570 }
7574 else
7579 /* If this is a qualified type and this field will always be
7580 present, we are done. */
7584 }
7586 /* If this used to be a qualified union type, but we now know what
7587 field will be present, make this a normal union. */
7598 /* If the size was originally a constant use it. */
7601 {
7605 }
7608 }
7612 }
7613 }
7614 \f
7615 /* Return the "RM size" of GNU_TYPE. This is the actual number of bits
7616 needed to represent the object. */
7618 tree
7620 {
7621 /* For integer types, this is the precision. For record types, we store
7622 the size explicitly. For other types, this is just the size. */
7628 /* Return the rm_size of the actual data plus the size of the template. */
7629 return
7639 else
7641 }
7642 \f
7643 /* Return an identifier representing the external name to be used for
7644 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
7645 and the specified suffix. */
7647 tree
7649 {
7658 /* A variable using the Stdcall convention (meaning we are running
7659 on a Windows box) live in a DLL. Here we adjust its name to use
7660 the jump-table, the _imp__NAME contains the address for the NAME
7661 variable. */
7664 {
7671 }
7674 }
7676 /* Return the name to be used for GNAT_ENTITY. If a type, create a
7677 fully-qualified name, possibly with type information encoding.
7678 Otherwise, return the name. */
7680 tree
7682 {
7685 }
7687 /* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
7688 string, return a new IDENTIFIER_NODE that is the concatenation of
7689 the name in GNU_ID and SUFFIX. */
7691 tree
7693 {
7701 }