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1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2008, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 3, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License along with GCC; see the file COPYING3. If not see *
19 * <http://www.gnu.org/licenses/>. *
20 * *
21 * GNAT was originally developed by the GNAT team at New York University. *
22 * Extensive contributions were provided by Ada Core Technologies Inc. *
23 * *
24 ****************************************************************************/
56 #ifndef MAX_FIXED_MODE_SIZE
57 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
58 #endif
60 /* Convention_Stdcall should be processed in a specific way on Windows targets
61 only. The macro below is a helper to avoid having to check for a Windows
62 specific attribute throughout this unit. */
64 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
65 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
66 #else
67 #define Has_Stdcall_Convention(E) (0)
68 #endif
70 struct incomplete
71 {
73 tree old_type;
74 Entity_Id full_type;
75 };
77 /* These variables are used to defer recursively expanding incomplete types
78 while we are processing an array, a record or a subprogram type. */
82 /* This variable is used to delay expanding From_With_Type types until the
83 end of the spec. */
86 /* These variables are used to defer finalizing types. The element of the
87 list is the TYPE_DECL associated with the type. */
91 /* A hash table used to cache the result of annotate_value. */
125 /* Return true if GNAT_ADDRESS is a compile time known value.
126 In particular catch System'To_Address. */
128 static bool
130 {
134 }
136 /* Given GNAT_ENTITY, an entity in the incoming GNAT tree, return a
137 GCC type corresponding to that entity. GNAT_ENTITY is assumed to
138 refer to an Ada type. */
140 tree
142 {
143 tree gnu_decl;
145 /* The back end never attempts to annotate generic types */
149 /* Convert the ada entity type into a GCC TYPE_DECL node. */
153 }
154 \f
155 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
156 entity, this routine returns the equivalent GCC tree for that entity
157 (an ..._DECL node) and associates the ..._DECL node with the input GNAT
158 defining identifier.
160 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
161 initial value (in GCC tree form). This is optional for variables.
162 For renamed entities, GNU_EXPR gives the object being renamed.
164 DEFINITION is nonzero if this call is intended for a definition. This is
165 used for separate compilation where it necessary to know whether an
166 external declaration or a definition should be created if the GCC equivalent
167 was not created previously. The value of 1 is normally used for a nonzero
168 DEFINITION, but a value of 2 is used in special circumstances, defined in
169 the code. */
171 tree
173 {
175 tree gnu_entity_id;
177 /* Contains the gnu XXXX_DECL tree node which is equivalent to the input
178 GNAT tree. This node will be associated with the GNAT node by calling
179 the save_gnu_tree routine at the end of the `switch' statement. */
181 /* true if we have already saved gnu_decl as a gnat association. */
183 /* Nonzero if we incremented defer_incomplete_level. */
185 /* Nonzero if we incremented force_global. */
187 /* Nonzero if we should check to see if elaborated during processing. */
189 /* Nonzero if we made GNU_DECL and its type here. */
195 Entity_Id gnat_temp;
196 unsigned int esize
206 bool imported_p
210 /* Since a use of an Itype is a definition, process it as such if it
211 is not in a with'ed unit. */
216 {
217 /* Ensure that we are in a subprogram mentioned in the Scope
218 chain of this entity, our current scope is global,
219 or that we encountered a task or entry (where we can't currently
220 accurately check scoping). */
223 {
226 }
230 {
235 gnat_temp
247 && (current_function_decl
249 {
252 }
253 }
255 /* This abort means the entity "gnat_entity" has an incorrect scope,
256 i.e. that its scope does not correspond to the subprogram in which
257 it is declared */
259 }
261 /* If this is entity 0, something went badly wrong. */
264 /* If we've already processed this entity, return what we got last time.
265 If we are defining the node, we should not have already processed it.
266 In that case, we will abort below when we try to save a new GCC tree for
267 this object. We also need to handle the case of getting a dummy type
268 when a Full_View exists. */
272 {
279 {
285 }
288 }
290 /* If this is a numeric or enumeral type, or an access type, a nonzero
291 Esize must be specified unless it was specified by the programmer. */
300 /* Likewise, RM_Size must be specified for all discrete and fixed-point
301 types. */
305 /* Get the name of the entity and set up the line number and filename of
306 the original definition for use in any decl we make. */
310 /* If we get here, it means we have not yet done anything with this
311 entity. If we are not defining it here, it must be external,
312 otherwise we should have defined it already. */
319 /* For cases when we are not defining (i.e., we are referencing from
320 another compilation unit) Public entities, show we are at global level
321 for the purpose of computing scopes. Don't do this for components or
322 discriminants since the relevant test is whether or not the record is
323 being defined. But do this for Imported functions or procedures in
324 all cases. */
332 /* Handle any attributes directly attached to the entity. */
336 /* Machine_Attributes on types are expected to be propagated to subtypes.
337 The corresponding Gigi_Rep_Items are only attached to the first subtype
338 though, so we handle the propagation here. */
345 {
347 /* If this is a use of a deferred constant, get its full
348 declaration. */
350 {
355 }
357 /* If we have an external constant that we are not defining, get the
358 expression that is was defined to represent. We may throw that
359 expression away later if it is not a constant. Do not retrieve the
360 expression if it is an aggregate or allocator, because in complex
361 instantiation contexts it may not be expanded */
371 /* Ignore deferred constant definitions; they are processed fully in the
372 front-end. For deferred constant references get the full definition.
373 On the other hand, constants that are renamings are handled like
374 variable renamings. If No_Initialization is set, this is not a
375 deferred constant but a constant whose value is built manually. */
379 {
383 }
386 {
391 }
396 /* We used to special case VMS exceptions here to directly map them to
397 their associated condition code. Since this code had to be masked
398 dynamically to strip off the severity bits, this caused trouble in
399 the GCC/ZCX case because the "type" pointers we store in the tables
400 have to be static. We now don't special case here anymore, and let
401 the regular processing take place, which leaves us with a regular
402 exception data object for VMS exceptions too. The condition code
403 mapping is taken care of by the front end and the bitmasking by the
404 runtime library. */
409 {
410 /* The GNAT record where the component was defined. */
413 /* If the variable is an inherited record component (in the case of
414 extended record types), just return the inherited entity, which
415 must be a FIELD_DECL. Likewise for discriminants.
416 For discriminants of untagged records which have explicit
417 stored discriminants, return the entity for the corresponding
418 stored discriminant. Also use Original_Record_Component
419 if the record has a private extension. */
423 {
424 gnu_decl
429 }
431 /* If the enclosing record has explicit stored discriminants,
432 then it is an untagged record. If the Corresponding_Discriminant
433 is not empty then this must be a renamed discriminant and its
434 Original_Record_Component must point to the corresponding explicit
435 stored discriminant (i.e., we should have taken the previous
436 branch). */
440 {
441 /* A tagged record has no explicit stored discriminants. */
445 gnu_decl
450 }
454 {
459 }
461 /* If the enclosing record has explicit stored discriminants,
462 then it is an untagged record. If the Corresponding_Discriminant
463 is not empty then this must be a renamed discriminant and its
464 Original_Record_Component must point to the corresponding explicit
465 stored discriminant (i.e., we should have taken the first
466 branch). */
473 /* Otherwise, if we are not defining this and we have no GCC type
474 for the containing record, make one for it. Then we should
475 have made our own equivalent. */
477 {
478 /* ??? If this is in a record whose scope is a protected
479 type and we have an Original_Record_Component, use it.
480 This is a workaround for major problems in protected type
481 handling. */
488 {
489 gnu_decl
495 }
501 }
503 else
504 /* Here we have no GCC type and this is a reference rather than a
505 definition. This should never happen. Most likely the cause is a
506 reference before declaration in the gnat tree for gnat_entity. */
508 }
514 /* Simple variables, loop variables, Out parameters, and exceptions. */
515 object:
516 {
518 bool const_flag
530 tree gnu_object_size;
533 {
537 else
539 }
541 /* Get the type after elaborating the renamed object. */
544 /* For a debug renaming declaration, build a pure debug entity. */
546 {
547 rtx addr;
549 /* The (MEM (CONST (0))) pattern is prescribed by STABS. */
552 else
557 }
559 /* If this is a loop variable, its type should be the base type.
560 This is because the code for processing a loop determines whether
561 a normal loop end test can be done by comparing the bounds of the
562 loop against those of the base type, which is presumed to be the
563 size used for computation. But this is not correct when the size
564 of the subtype is smaller than the type. */
568 /* Reject non-renamed objects whose types are unconstrained arrays or
569 any object whose type is a dummy type or VOID_TYPE. */
575 {
578 force_global--;
580 }
582 /* If an alignment is specified, use it if valid. Note that
583 exceptions are objects but don't have alignments. We must do this
584 before we validate the size, since the alignment can affect the
585 size. */
587 {
593 }
595 /* If we are defining the object, see if it has a Size value and
596 validate it if so. If we are not defining the object and a Size
597 clause applies, simply retrieve the value. We don't want to ignore
598 the clause and it is expected to have been validated already. Then
599 get the new type, if any. */
608 {
609 gnu_type
615 }
617 /* If this object has self-referential size, it must be a record with
618 a default value. We are supposed to allocate an object of the
619 maximum size in this case unless it is a constant with an
620 initializing expression, in which case we can get the size from
621 that. Note that the resulting size may still be a variable, so
622 this may end up with an indirect allocation. */
625 {
627 {
630 {
631 /* If the initializing expression is itself a constant,
632 despite having a nominal type with self-referential
633 size, we can get the size directly from it. */
636 == RECORD_TYPE
637 && TYPE_IS_PADDING_P
641 || DECL_READONLY_ONCE_ELAB
644 else
645 gnu_size
647 }
648 else
650 }
651 /* We may have no GNU_EXPR because No_Initialization is
652 set even though there's an Expression. */
657 gnu_size
659 (Etype
661 else
662 {
665 }
666 }
668 /* If the size is zero bytes, make it one byte since some linkers have
669 trouble with zero-sized objects. If the object will have a
670 template, that will make it nonzero so don't bother. Also avoid
671 doing that for an object renaming or an object with an address
672 clause, as we would lose useful information on the view size
673 (e.g. for null array slices) and we are not allocating the object
674 here anyway. */
687 /* If this is an object with no specified size and alignment, and
688 if either it is atomic or we are not optimizing alignment for
689 space and it is composite and not an exception, an Out parameter
690 or a reference to another object, and the size of its type is a
691 constant, set the alignment to the smallest one which is not
692 smaller than the size, with an appropriate cap. */
700 && !imported_p
704 {
705 /* No point in jumping through all the hoops needed in order
706 to support BIGGEST_ALIGNMENT if we don't really have to. */
708 ? BIGGEST_ALIGNMENT
714 else
717 /* But make sure not to under-align the object. */
721 /* And honor the minimum valid atomic alignment, if any. */
722 #ifdef MINIMUM_ATOMIC_ALIGNMENT
725 #endif
726 }
728 /* If the object is set to have atomic components, find the component
729 type and validate it.
731 ??? Note that we ignore Has_Volatile_Components on objects; it's
732 not at all clear what to do in that case. */
735 {
744 }
746 /* Now check if the type of the object allows atomic access. Note
747 that we must test the type, even if this object has size and
748 alignment to allow such access, because we will be going
749 inside the padded record to assign to the object. We could fix
750 this by always copying via an intermediate value, but it's not
751 clear it's worth the effort. */
755 /* If this is an aliased object with an unconstrained nominal subtype,
756 make a type that includes the template. */
760 {
761 tree gnu_fat
764 gnu_type
768 }
770 #ifdef MINIMUM_ATOMIC_ALIGNMENT
771 /* If the size is a constant and no alignment is specified, force
772 the alignment to be the minimum valid atomic alignment. The
773 restriction on constant size avoids problems with variable-size
774 temporaries; if the size is variable, there's no issue with
775 atomic access. Also don't do this for a constant, since it isn't
776 necessary and can interfere with constant replacement. Finally,
777 do not do it for Out parameters since that creates an
778 size inconsistency with In parameters. */
787 #endif
789 /* Make a new type with the desired size and alignment, if needed.
790 But do not take into account alignment promotions to compute the
791 size of the object. */
798 /* Make a volatile version of this object's type if we are to make
799 the object volatile. We also interpret 13.3(19) conservatively
800 and disallow any optimizations for an object covered by it. */
803 /* Exclude exported constants created by the compiler,
804 which should boil down to static dispatch tables and
805 make it possible to put them in read-only memory. */
814 /* If this is a renaming, avoid as much as possible to create a new
815 object. However, in several cases, creating it is required.
816 This processing needs to be applied to the raw expression so
817 as to make it more likely to rename the underlying object. */
819 {
822 /* If the renamed object had padding, strip off the reference
823 to the inner object and reset our type. */
826 == RECORD_TYPE
828 /* Strip useless conversions around the object. */
830 {
833 }
835 /* Case 1: If this is a constant renaming stemming from a function
836 call, treat it as a normal object whose initial value is what
837 is being renamed. RM 3.3 says that the result of evaluating a
838 function call is a constant object. As a consequence, it can
839 be the inner object of a constant renaming. In this case, the
840 renaming must be fully instantiated, i.e. it cannot be a mere
841 reference to (part of) an existing object. */
843 {
849 }
851 /* Otherwise, see if we can proceed with a stabilized version of
852 the renamed entity or if we need to make a new object. */
854 {
858 /* Case 2: If the renaming entity need not be materialized and
859 the renamed expression is something we can stabilize, use
860 that for the renaming. At the global level, we can only do
861 this if we know no SAVE_EXPRs need be made, because the
862 expression we return might be used in arbitrary conditional
863 branches so we must force the SAVE_EXPRs evaluation
864 immediately and this requires a function context. */
869 {
870 maybe_stable_expr
874 {
876 /* ??? No DECL_EXPR is created so we need to mark
877 the expression manually lest it is shared. */
883 }
885 /* The stabilization failed. Keep maybe_stable_expr
886 untouched here to let the pointer case below know
887 about that failure. */
888 }
890 /* Case 3: If this is a constant renaming and creating a
891 new object is allowed and cheap, treat it as a normal
892 object whose initial value is what is being renamed. */
894 ;
896 /* Case 4: Make this into a constant pointer to the object we
897 are to rename and attach the object to the pointer if it is
898 something we can stabilize.
900 From the proper scope, attached objects will be referenced
901 directly instead of indirectly via the pointer to avoid
902 subtle aliasing problems with non-addressable entities.
903 They have to be stable because we must not evaluate the
904 variables in the expression every time the renaming is used.
905 The pointer is called a "renaming" pointer in this case.
907 In the rare cases where we cannot stabilize the renamed
908 object, we just make a "bare" pointer, and the renamed
909 entity is always accessed indirectly through it. */
910 else
911 {
916 /* If the previous attempt at stabilizing failed, there
917 is no point in trying again and we reuse the result
918 without attaching it to the pointer. In this case it
919 will only be used as the initializing expression of
920 the pointer and thus needs no special treatment with
921 regard to multiple evaluations. */
923 ;
925 /* Otherwise, try to stabilize and attach the expression
926 to the pointer if the stabilization succeeds.
928 Note that this might introduce SAVE_EXPRs and we don't
929 check whether we're at the global level or not. This
930 is fine since we are building a pointer initializer and
931 neither the pointer nor the initializing expression can
932 be accessed before the pointer elaboration has taken
933 place in a correct program.
935 These SAVE_EXPRs will be evaluated at the right place
936 by either the evaluation of the initializer for the
937 non-global case or the elaboration code for the global
938 case, and will be attached to the elaboration procedure
939 in the latter case. */
940 else
941 {
942 maybe_stable_expr
948 /* Attaching is actually performed downstream, as soon
949 as we have a VAR_DECL for the pointer we make. */
950 }
952 gnu_expr
957 }
958 }
959 }
961 /* If this is an aliased object whose nominal subtype is unconstrained,
962 the object is a record that contains both the template and
963 the object. If there is an initializer, it will have already
964 been converted to the right type, but we need to create the
965 template if there is no initializer. */
969 /* Beware that padding might have been introduced
970 via maybe_pad_type above. */
973 == RECORD_TYPE
974 && TYPE_CONTAINS_TEMPLATE_P
977 {
978 tree template_field
983 gnu_expr
984 = gnat_build_constructor
986 tree_cons
990 NULL_TREE),
991 NULL_TREE));
992 }
994 /* Convert the expression to the type of the object except in the
995 case where the object's type is unconstrained or the object's type
996 is a padded record whose field is of self-referential size. In
997 the former case, converting will generate unnecessary evaluations
998 of the CONSTRUCTOR to compute the size and in the latter case, we
999 want to only copy the actual data. */
1005 && (CONTAINS_PLACEHOLDER_P
1009 /* If this is a pointer and it does not have an initializing
1010 expression, initialize it to NULL, unless the object is
1011 imported. */
1017 /* If we are defining the object and it has an Address clause we must
1018 get the address expression from the saved GCC tree for the
1019 object if the object has a Freeze_Node. Otherwise, we elaborate
1020 the address expression here since the front-end has guaranteed
1021 in that case that the elaboration has no effects. Note that
1022 only the latter mechanism is currently in use. */
1024 {
1025 tree gnu_address
1031 /* Ignore the size. It's either meaningless or was handled
1032 above. */
1034 /* Convert the type of the object to a reference type that can
1035 alias everything as per 13.3(19). */
1036 gnu_type
1044 /* If we don't have an initializing expression for the underlying
1045 variable, the initializing expression for the pointer is the
1046 specified address. Otherwise, we have to make a COMPOUND_EXPR
1047 to assign both the address and the initial value. */
1050 else
1051 gnu_expr
1053 build_binary_op
1056 gnu_address),
1057 gnu_expr),
1058 gnu_address);
1059 }
1061 /* If it has an address clause and we are not defining it, mark it
1062 as an indirect object. Likewise for Stdcall objects that are
1063 imported. */
1067 {
1068 /* Convert the type of the object to a reference type that can
1069 alias everything as per 13.3(19). */
1070 gnu_type
1074 /* No point in taking the address of an initializing expression
1075 that isn't going to be used. */
1078 /* If it has an address clause whose value is known at compile
1079 time, make the object a CONST_DECL. This will avoid a
1080 useless dereference. */
1082 {
1083 Node_Id gnat_address
1087 {
1090 }
1091 }
1094 }
1096 /* If we are at top level and this object is of variable size,
1097 make the actual type a hidden pointer to the real type and
1098 make the initializer be a memory allocation and initialization.
1099 Likewise for objects we aren't defining (presumed to be
1100 external references from other packages), but there we do
1101 not set up an initialization.
1103 If the object's size overflows, make an allocator too, so that
1104 Storage_Error gets raised. Note that we will never free
1105 such memory, so we presume it never will get allocated. */
1110 || (gnu_size
1114 {
1120 /* In case this was a aliased object whose nominal subtype is
1121 unconstrained, the pointer above will be a thin pointer and
1122 build_allocator will automatically make the template.
1124 If we have a template initializer only (that we made above),
1125 pretend there is none and rely on what build_allocator creates
1126 again anyway. Otherwise (if we have a full initializer), get
1127 the data part and feed that to build_allocator.
1129 If we are elaborating a mutable object, tell build_allocator to
1130 ignore a possibly simpler size from the initializer, if any, as
1131 we must allocate the maximum possible size in this case. */
1134 {
1139 {
1140 gnu_alloc_type
1147 else
1148 gnu_expr
1149 = build_component_ref
1153 }
1159 gnat_entity);
1163 }
1164 else
1165 {
1168 }
1169 }
1171 /* If this object would go into the stack and has an alignment larger
1172 than the largest stack alignment the back-end can honor, resort to
1173 a variable of "aligning type". */
1176 {
1177 /* Create the new variable. No need for extra room before the
1178 aligned field as this is in automatic storage. */
1179 tree gnu_new_type
1183 tree gnu_new_var
1188 /* Initialize the aligned field if we have an initializer. */
1190 add_stmt_with_node
1192 build_component_ref
1195 gnu_expr),
1196 gnat_entity);
1198 /* And setup this entity as a reference to the aligned field. */
1200 gnu_expr
1201 = build_unary_op
1209 }
1215 /* Convert the expression to the type of the object except in the
1216 case where the object's type is unconstrained or the object's type
1217 is a padded record whose field is of self-referential size. In
1218 the former case, converting will generate unnecessary evaluations
1219 of the CONSTRUCTOR to compute the size and in the latter case, we
1220 want to only copy the actual data. */
1226 && (CONTAINS_PLACEHOLDER_P
1230 /* If this name is external or there was a name specified, use it,
1231 unless this is a VMS exception object since this would conflict
1232 with the symbol we need to export in addition. Don't use the
1233 Interface_Name if there is an address clause (see CD30005). */
1242 /* If this is constant initialized to a static constant and the
1243 object has an aggregate type, force it to be statically
1244 allocated. */
1260 {
1263 {
1266 }
1267 }
1274 STACK_CHECK_MAX_VAR_SIZE))))
1279 gnat_entity);
1281 /* If this is a public constant or we're not optimizing and we're not
1282 making a VAR_DECL for it, make one just for export or debugger use.
1283 Likewise if the address is taken or if either the object or type is
1284 aliased. Make an external declaration for a reference, unless this
1285 is a Standard entity since there no real symbol at the object level
1286 for these. */
1295 {
1296 tree gnu_corr_var
1300 gnat_entity);
1304 /* As debugging information will be generated for the variable,
1305 do not generate information for the constant. */
1307 }
1309 /* If this is declared in a block that contains a block with an
1310 exception handler, we must force this variable in memory to
1311 suppress an invalid optimization. */
1318 /* Back-annotate Alignment and Esize of the object if not already
1319 known, except for when the object is actually a pointer to the
1320 real object, since alignment and size of a pointer don't have
1321 anything to do with those of the designated object. Note that
1322 we pick the values of the type, not those of the object, to
1323 shield ourselves from low-level platform-dependent adjustments
1324 like alignment promotion. This is both consistent with all the
1325 treatment above, where alignment and size are set on the type of
1326 the object and not on the object directly, and makes it possible
1327 to support confirming representation clauses in all cases. */
1334 {
1337 gnu_object_size
1341 }
1342 }
1346 /* Return a TYPE_DECL for "void" that we previously made. */
1351 /* A special case, for the types Character and Wide_Character in
1352 Standard, we do not list all the literals. So if the literals
1353 are not specified, make this an unsigned type. */
1355 {
1359 /* Set the TYPE_STRING_FLAG for Ada Character and
1360 Wide_Character types. This is needed by the dwarf-2 debug writer to
1361 distinguish between unsigned integer types and character types. */
1364 }
1366 /* Normal case of non-character type, or non-Standard character type */
1367 {
1368 /* Here we have a list of enumeral constants in First_Literal.
1369 We make a CONST_DECL for each and build into GNU_LITERAL_LIST
1370 the list to be places into TYPE_FIELDS. Each node in the list
1371 is a TREE_LIST node whose TREE_VALUE is the literal name
1372 and whose TREE_PURPOSE is the value of the literal.
1374 Esize contains the number of bits needed to represent the enumeral
1375 type, Type_Low_Bound also points to the first literal and
1376 Type_High_Bound points to the last literal. */
1378 Entity_Id gnat_literal;
1383 else
1391 {
1393 gnu_type);
1394 tree gnu_literal
1402 }
1406 /* Note that the bounds are updated at the end of this function
1407 because to avoid an infinite recursion when we get the bounds of
1408 this type, since those bounds are objects of this type. */
1409 }
1415 /* For integer types, just make a signed type the appropriate number
1416 of bits. */
1421 /* For modular types, make the unsigned type of the proper number of
1422 bits and then set up the modulus, if required. */
1423 {
1425 tree gnu_modulus;
1431 /* Find the smallest mode at least ESIZE bits wide and make a class
1432 using that mode. */
1437 ;
1444 /* Get the modulus in this type. If it overflows, assume it is because
1445 it is equal to 2**Esize. Note that there is no overflow checking
1446 done on unsigned type, so we detect the overflow by looking for
1447 a modulus of zero, which is otherwise invalid. */
1451 {
1456 }
1458 /* If we have to set TYPE_PRECISION different from its natural value,
1459 make a subtype to do do. Likewise if there is a modulus and
1460 it is not one greater than TYPE_MAX_VALUE. */
1464 {
1482 }
1483 }
1492 /* For integral subtypes, we make a new INTEGER_TYPE. Note
1493 that we do not want to call build_range_type since we would
1494 like each subtype node to be distinct. This will be important
1495 when memory aliasing is implemented.
1497 The TREE_TYPE field of the INTEGER_TYPE we make points to the
1498 parent type; this fact is used by the arithmetic conversion
1499 functions.
1501 We elaborate the Ancestor_Subtype if it is not in the current
1502 unit and one of our bounds is non-static. We do this to ensure
1503 consistent naming in the case where several subtypes share the same
1504 bounds by always elaborating the first such subtype first, thus
1505 using its name. */
1518 {
1521 }
1529 gnat_entity,
1536 gnat_entity,
1540 /* One of the above calls might have caused us to be elaborated,
1541 so don't blow up if so. */
1543 {
1546 }
1551 /* This should be an unsigned type if the lower bound is constant
1552 and non-negative or if the base type is unsigned; a signed type
1553 otherwise. */
1563 /* Inherit our alias set from what we're a subtype of. Subtypes
1564 are not different types and a pointer can designate any instance
1565 within a subtype hierarchy. */
1568 /* If the type we are dealing with is to represent a packed array,
1569 we need to have the bits left justified on big-endian targets
1570 and right justified on little-endian targets. We also need to
1571 ensure that when the value is read (e.g. for comparison of two
1572 such values), we only get the good bits, since the unused bits
1573 are uninitialized. Both goals are accomplished by wrapping the
1574 modular value in an enclosing struct. */
1577 {
1579 tree gnu_field;
1586 /* Propagate the alignment of the modular type to the record.
1587 This means that bitpacked arrays have "ceil" alignment for
1588 their size, which may seem counter-intuitive but makes it
1589 possible to easily overlay them on modular types. */
1593 /* Create a stripped-down declaration of the original type, mainly
1594 for debugging. */
1598 /* Don't notify the field as "addressable", since we won't be taking
1599 it's address and it would prevent create_field_decl from making a
1600 bitfield. */
1609 }
1611 /* If the type we are dealing with has got a smaller alignment than the
1612 natural one, we need to wrap it up in a record type and under-align
1613 the latter. We reuse the padding machinery for this purpose. */
1618 {
1620 tree gnu_field;
1628 /* Create a stripped-down declaration of the original type, mainly
1629 for debugging. */
1633 /* Don't notify the field as "addressable", since we won't be taking
1634 it's address and it would prevent create_field_decl from making a
1635 bitfield. */
1644 }
1646 /* Otherwise reset the alignment lest we computed it above. */
1647 else
1653 /* If this is a VAX floating-point type, use an integer of the proper
1654 size. All the operations will be handled with ASM statements. */
1656 {
1661 sizetype));
1663 }
1665 /* The type of the Low and High bounds can be our type if this is
1666 a type from Standard, so set them at the end of the function. */
1674 {
1677 }
1679 {
1706 /* One of the above calls might have caused us to be elaborated,
1707 so don't blow up if so. */
1709 {
1712 }
1716 /* Inherit our alias set from what we're a subtype of, as for
1717 integer subtypes. */
1719 }
1722 /* Array and String Types and Subtypes
1724 Unconstrained array types are represented by E_Array_Type and
1725 constrained array types are represented by E_Array_Subtype. There
1726 are no actual objects of an unconstrained array type; all we have
1727 are pointers to that type.
1729 The following fields are defined on array types and subtypes:
1731 Component_Type Component type of the array.
1732 Number_Dimensions Number of dimensions (an int).
1733 First_Index Type of first index. */
1737 {
1743 int firstdim
1745 int nextdim
1752 tree gnu_max_size_unit;
1753 Entity_Id gnat_ind_subtype;
1754 Entity_Id gnat_ind_base_subtype;
1755 tree gnu_template_reference;
1756 tree tem;
1761 /* Make a node for the array. If we are not defining the array
1762 suppress expanding incomplete types. */
1768 /* Build the fat pointer type. Use a "void *" object instead of
1769 a pointer to the array type since we don't have the array type
1770 yet (it will reference the fat pointer via the bounds). */
1773 ptr_void_type_node,
1776 gnu_ptr_template,
1779 /* Make sure we can put this into a register. */
1782 /* Do not finalize this record type since the types of its fields
1783 are still incomplete at this point. */
1787 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1788 is the fat pointer. This will be used to access the individual
1789 fields once we build them. */
1793 gnu_template_reference
1797 /* Now create the GCC type for each index and add the fields for
1798 that index to the template. */
1800 gnat_ind_base_subtype
1806 {
1808 tree gnu_ind_subtype
1810 tree gnu_base_subtype
1812 tree gnu_base_min
1814 tree gnu_base_max
1818 /* Make the FIELD_DECLs for the minimum and maximum of this
1819 type and then make extractions of that field from the
1820 template. */
1823 gnu_ind_subtype,
1827 gnu_ind_subtype,
1836 /* We can't use build_component_ref here since the template
1837 type isn't complete yet. */
1840 NULL_TREE);
1843 NULL_TREE);
1846 /* Make a range type with the new ranges, but using
1847 the Ada subtype. Then we convert to sizetype. */
1853 gnat_entity);
1854 /* Update the maximum size of the array, in elements. */
1855 gnu_max_size
1859 gnu_base_min)));
1863 }
1866 gnu_template_fields
1869 /* Install all the fields into the template. */
1873 /* Now make the array of arrays and update the pointer to the array
1874 in the fat pointer. Note that it is the first field. */
1877 /* Try to get a smaller form of the component if needed. */
1890 /* Get and validate any specified Component_Size, but if Packed,
1891 ignore it since the front end will have taken care of it. */
1892 gnu_comp_size
1894 gnat_entity,
1899 /* If the component type is a RECORD_TYPE that has a self-referential
1900 size, use the maxium size. */
1906 {
1907 tree orig_tem;
1912 /* If a padding record was made, declare it now since it will
1913 never be declared otherwise. This is necessary to ensure
1914 that its subtrees are properly marked. */
1917 gnat_entity);
1918 }
1924 /* If Component_Size is not already specified, annotate it with the
1925 size of the component. */
1935 gnu_max_size),
1939 {
1944 }
1946 /* If an alignment is specified, use it if valid. But ignore it for
1947 types that represent the unpacked base type for packed arrays. If
1948 the alignment was requested with an explicit user alignment clause,
1949 state so. */
1952 {
1959 }
1965 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
1966 corresponding fat pointer. */
1973 /* If the maximum size doesn't overflow, use it. */
1988 /* Give the fat pointer type a name. */
1993 /* Create the type to be used as what a thin pointer designates: an
1994 record type for the object and its template with the field offsets
1995 shifted to have the template at a negative offset. */
2003 /* Give the thin pointer type a name. */
2007 gnat_entity);
2008 }
2014 /* This is the actual data type for array variables. Multidimensional
2015 arrays are implemented in the gnu tree as arrays of arrays. Note
2016 that for the moment arrays which have sparse enumeration subtypes as
2017 index components create sparse arrays, which is obviously space
2018 inefficient but so much easier to code for now.
2020 Also note that the subtype never refers to the unconstrained
2021 array type, which is somewhat at variance with Ada semantics.
2023 First check to see if this is simply a renaming of the array
2024 type. If so, the result is the array type. */
2029 else
2030 {
2033 int first_dim
2036 int next_dim
2038 Entity_Id gnat_ind_subtype;
2039 Entity_Id gnat_ind_base_subtype;
2044 tree gnu_max_size_unit;
2048 /* First create the gnu types for each index. Create types for
2049 debugging information to point to the index types if the
2050 are not integer types, have variable bounds, or are
2051 wider than sizetype. */
2054 gnat_ind_base_subtype
2060 {
2061 tree gnu_index_subtype
2063 tree gnu_min
2065 tree gnu_max
2067 tree gnu_base_subtype
2069 tree gnu_base_min
2071 tree gnu_base_max
2074 tree gnu_base_base_min
2076 tree gnu_base_base_max
2078 tree gnu_high;
2079 tree gnu_this_max;
2081 /* If the minimum and maximum values both overflow in
2082 SIZETYPE, but the difference in the original type
2083 does not overflow in SIZETYPE, ignore the overflow
2084 indications. */
2092 && (!TREE_OVERFLOW
2096 {
2099 }
2101 /* Similarly, if the range is null, use bounds of 1..0 for
2102 the sizetype bounds. */
2114 /* Now compute the size of this bound. We need to provide
2115 GCC with an upper bound to use but have to deal with the
2116 "superflat" case. There are three ways to do this. If we
2117 can prove that the array can never be superflat, we can
2118 just use the high bound of the index subtype. If we can
2119 prove that the low bound minus one can't overflow, we
2120 can do this as MAX (hb, lb - 1). Otherwise, we have to use
2121 the expression hb >= lb ? hb : lb - 1. */
2124 /* See if the base array type is already flat. If it is, we
2125 are probably compiling an ACVC test, but it will cause the
2126 code below to malfunction if we don't handle it specially. */
2134 /* If gnu_high is now an integer which overflowed, the array
2135 cannot be superflat. */
2142 else
2143 gnu_high
2144 = build_cond_expr
2151 gnat_entity);
2153 /* Also compute the maximum size of the array. Here we
2154 see if any constraint on the index type of the base type
2155 can be used in the case of self-referential bound on
2156 the index type of the subtype. We look for a non-"infinite"
2157 and non-self-referential bound from any type involved and
2158 handle each bound separately. */
2187 gnu_this_max
2191 gnu_base_min)),
2192 size_zero_node);
2198 gnu_max_size
2212 }
2214 /* Then flatten: create the array of arrays. For an array type
2215 used to implement a packed array, get the component type from
2216 the original array type since the representation clauses that
2217 can affect it are on the latter. */
2220 {
2225 /* One of the above calls might have caused us to be elaborated,
2226 so don't blow up if so. */
2228 {
2231 }
2232 }
2233 else
2234 {
2237 /* One of the above calls might have caused us to be elaborated,
2238 so don't blow up if so. */
2240 {
2243 }
2245 /* Try to get a smaller form of the component if needed. */
2255 /* Get and validate any specified Component_Size, but if Packed,
2256 ignore it since the front end will have taken care of it. */
2257 gnu_comp_size
2259 gnat_entity,
2264 /* If the component type is a RECORD_TYPE that has a
2265 self-referential size, use the maxium size. */
2272 {
2273 tree orig_gnu_type;
2274 gnu_type
2280 /* If a padding record was made, declare it now since it
2281 will never be declared otherwise. This is necessary
2282 to ensure that its subtrees are properly marked. */
2286 }
2292 }
2301 {
2306 }
2308 /* If we are at file level and this is a multi-dimensional array, we
2309 need to make a variable corresponding to the stride of the
2310 inner dimensions. */
2312 {
2314 tree gnu_arr_type;
2320 {
2328 /* ??? For now, store the size as a multiple of the
2329 alignment of the element type in bytes so that we
2330 can see the alignment from the tree. */
2332 = build_binary_op
2334 elaborate_expression_1
2344 /* ??? create_type_decl is not invoked on the inner types so
2345 the MULT_EXPR node built above will never be marked. */
2347 }
2348 }
2350 /* If we need to write out a record type giving the names of
2351 the bounds, do it now. */
2353 {
2356 tree gnu_field;
2362 {
2363 tree gnu_type_name
2370 integer_type_node,
2371 gnu_bound_rec_type,
2375 }
2379 }
2387 /* If our size depends on a placeholder and the maximum size doesn't
2388 overflow, use it. */
2395 {
2401 }
2403 /* Set our alias set to that of our base type. This gives all
2404 array subtypes the same alias set. */
2406 }
2408 /* If this is a packed type, make this type the same as the packed
2409 array type, but do some adjusting in the type first. */
2412 {
2413 Entity_Id gnat_index;
2414 tree gnu_inner_type;
2416 /* First finish the type we had been making so that we output
2417 debugging information for it */
2418 gnu_type
2421 | (TYPE_QUAL_VOLATILE
2429 /* Save it as our equivalent in case the call below elaborates
2430 this type again. */
2445 /* We need to point the type we just made to our index type so
2446 the actual bounds can be put into a template. */
2452 {
2454 {
2455 /* The TYPE_ACTUAL_BOUNDS field is also used for the modulus.
2456 If it is, we need to make another type. */
2458 {
2459 tree gnu_subtype;
2476 }
2479 }
2485 SET_TYPE_ACTUAL_BOUNDS
2492 SET_TYPE_ACTUAL_BOUNDS
2499 }
2500 }
2502 /* Abort if packed array with no packed array type field set. */
2503 else
2509 /* Create the type for a string literal. */
2510 {
2511 Entity_Id gnat_full_type
2516 tree gnu_string_array_type
2518 tree gnu_string_index_type
2521 tree gnu_lower_bound
2526 tree gnu_upper_bound
2528 gnu_lower_bound,
2530 tree gnu_range_type
2533 tree gnu_index_type
2540 gnu_type
2542 gnu_index_type);
2544 }
2547 /* Record Types and Subtypes
2549 The following fields are defined on record types:
2551 Has_Discriminants True if the record has discriminants
2552 First_Discriminant Points to head of list of discriminants
2553 First_Entity Points to head of list of fields
2554 Is_Tagged_Type True if the record is tagged
2556 Implementation of Ada records and discriminated records:
2558 A record type definition is transformed into the equivalent of a C
2559 struct definition. The fields that are the discriminants which are
2560 found in the Full_Type_Declaration node and the elements of the
2561 Component_List found in the Record_Type_Definition node. The
2562 Component_List can be a recursive structure since each Variant of
2563 the Variant_Part of the Component_List has a Component_List.
2565 Processing of a record type definition comprises starting the list of
2566 field declarations here from the discriminants and the calling the
2567 function components_to_record to add the rest of the fields from the
2568 component list and return the gnu type node. The function
2569 components_to_record will call itself recursively as it traverses
2570 the tree. */
2574 {
2575 gnu_type
2576 = build_complex_type
2577 (get_unpadded_type
2580 (Component_List
2581 (Type_Definition
2585 }
2587 {
2590 Entity_Id gnat_field;
2591 tree gnu_field;
2593 tree gnu_get_parent;
2594 /* Set PACKED in keeping with gnat_to_gnu_field. */
2595 int packed
2607 bool is_extension
2611 /* See if all fields have a rep clause. Stop when we find one
2612 that doesn't. */
2621 /* If this is a record extension, go a level further to find the
2622 record definition. Also, verify we have a Parent_Subtype. */
2624 {
2631 }
2633 /* Make a node for the record. If we are not defining the record,
2634 suppress expanding incomplete types. */
2642 /* If both a size and rep clause was specified, put the size in
2643 the record type now so that it can get the proper mode. */
2647 /* Always set the alignment here so that it can be used to
2648 set the mode, if it is making the alignment stricter. If
2649 it is invalid, it will be checked again below. If this is to
2650 be Atomic, choose a default alignment of a word unless we know
2651 the size and it's smaller. */
2658 /* If a type needs strict alignment, the minimum size will be the
2659 type size instead of the RM size (see validate_size). Cap the
2660 alignment, lest it causes this type size to become too large. */
2663 {
2668 }
2669 else
2672 /* If we have a Parent_Subtype, make a field for the parent. If
2673 this record has rep clauses, force the position to zero. */
2675 {
2677 tree gnu_parent;
2679 /* A major complexity here is that the parent subtype will
2680 reference our discriminants in its Discriminant_Constraint
2681 list. But those must reference the parent component of this
2682 record which is of the parent subtype we have not built yet!
2683 To break the circle we first build a dummy COMPONENT_REF which
2684 represents the "get to the parent" operation and initialize
2685 each of those discriminants to a COMPONENT_REF of the above
2686 dummy parent referencing the corresponding discriminant of the
2687 base type of the parent subtype. */
2691 void_type_node),
2692 NULL_TREE);
2699 save_gnu_tree
2703 gnu_get_parent,
2706 NULL_TREE),
2709 /* Then we build the parent subtype. */
2712 /* Finally we fix up both kinds of twisted COMPONENT_REF we have
2713 initially built. The discriminants must reference the fields
2714 of the parent subtype and not those of its base type for the
2715 placeholder machinery to properly work. */
2721 {
2731 }
2733 /* The "get to the parent" COMPONENT_REF must be given its
2734 proper type... */
2737 /* ...and reference the _parent field of this record. */
2738 gnu_field_list
2746 }
2748 /* Make the fields for the discriminants and put them into the record
2749 unless it's an Unchecked_Union. */
2754 {
2755 /* If this is a record extension and this discriminant
2756 is the renaming of another discriminant, we've already
2757 handled the discriminant above. */
2762 gnu_field
2765 /* Make an expression using a PLACEHOLDER_EXPR from the
2766 FIELD_DECL node just created and link that with the
2767 corresponding GNAT defining identifier. Then add to the
2768 list of fields. */
2777 {
2780 }
2781 }
2783 /* Put the discriminants into the record (backwards), so we can
2784 know the appropriate discriminant to use for the names of the
2785 variants. */
2788 /* Add the listed fields into the record and finish it up. */
2794 /* We used to remove the associations of the discriminants and
2795 _Parent for validity checking, but we may need them if there's
2796 Freeze_Node for a subtype used in this record. */
2800 /* If it is a tagged record force the type to BLKmode to insure
2801 that these objects will always be placed in memory. Do the
2802 same thing for limited record types. */
2806 /* If this is a derived type, we must make the alias set of this type
2807 the same as that of the type we are derived from. We assume here
2808 that the other type is already frozen. */
2814 /* Fill in locations of fields. */
2817 /* If there are any entities in the chain corresponding to
2818 components that we did not elaborate, ensure we elaborate their
2819 types if they are Itypes. */
2827 }
2831 /* If an equivalent type is present, that is what we should use.
2832 Otherwise, fall through to handle this like a record subtype
2833 since it may have constraints. */
2835 {
2839 }
2841 /* ... fall through ... */
2845 /* If Cloned_Subtype is Present it means this record subtype has
2846 identical layout to that type or subtype and we should use
2847 that GCC type for this one. The front end guarantees that
2848 the component list is shared. */
2850 {
2854 }
2856 /* Otherwise, first ensure the base type is elaborated. Then, if we are
2857 changing the type, make a new type with each field having the
2858 type of the field in the new subtype but having the position
2859 computed by transforming every discriminant reference according
2860 to the constraints. We don't see any difference between
2861 private and nonprivate type here since derivations from types should
2862 have been deferred until the completion of the private type. */
2863 else
2864 {
2866 tree gnu_base_type;
2867 tree gnu_orig_type;
2872 /* Get the base type initially for its alignment and sizes. But
2873 if it is a padded type, we do all the other work with the
2874 unpadded type. */
2880 else
2884 {
2887 }
2889 /* When the type has discriminants, and these discriminants
2890 affect the shape of what it built, factor them in.
2892 If we are making a subtype of an Unchecked_Union (must be an
2893 Itype), just return the type.
2895 We can't just use Is_Constrained because private subtypes without
2896 discriminants of full types with discriminants with default
2897 expressions are Is_Constrained but aren't constrained! */
2905 {
2906 Entity_Id gnat_field;
2908 tree gnu_pos_list
2911 BIGGEST_ALIGNMENT);
2912 tree gnu_subst_list
2914 definition);
2915 tree gnu_temp;
2931 {
2932 tree gnu_old_field
2935 tree gnu_offset
2937 gnu_pos_list));
2940 tree gnu_field_type
2944 unsigned int offset_align
2947 tree gnu_field;
2949 /* If there was a component clause, the field types must be
2950 the same for the type and subtype, so copy the data from
2951 the old field to avoid recomputation here. Also if the
2952 field is justified modular and the optimization in
2953 gnat_to_gnu_field was applied. */
2960 {
2963 }
2965 /* If the old field was packed and of constant size, we
2966 have to get the old size here, as it might differ from
2967 what the Etype conveys and the latter might overlap
2968 onto the following field. Try to arrange the type for
2969 possible better packing along the way. */
2973 {
2978 gnu_field_type
2980 }
2989 /* If the size is now a constant, we can set it as the
2990 size of the field when we make it. Otherwise, we need
2991 to deal with it specially. */
2995 gnu_field
2996 = create_field_decl
3002 {
3011 bitsize_unit_node));
3013 }
3017 SET_DECL_ORIGINAL_FIELD
3028 }
3030 /* Now go through the entities again looking for Itypes that
3031 we have not elaborated but should (e.g., Etypes of fields
3032 that have Original_Components). */
3040 /* Do not finalize it since we're going to modify it below. */
3044 /* Now set the size, alignment and alias set of the new type to
3045 match that of the old one, doing any substitutions, as
3046 above. */
3072 SET_TYPE_ADA_SIZE
3077 /* Reapply variable_size since we have changed the sizes. */
3082 /* Recompute the mode of this record type now that we know its
3083 actual size. */
3086 /* Fill in locations of fields. */
3089 /* We've built a new type, make an XVS type to show what this
3090 is a subtype of. Some debuggers require the XVS type to be
3091 output first, so do it in that order. */
3093 {
3104 integer_type_node,
3105 gnu_subtype_marker,
3109 }
3111 /* Now we can finalize it. */
3113 }
3115 /* Otherwise, go down all the components in the new type and
3116 make them equivalent to those in the base type. */
3117 else
3124 gnat_to_gnu_field_decl
3126 }
3130 /* Use the special descriptor type for dispatch tables if needed,
3131 that is to say for the Prim_Ptr of a-tags.ads and its clones.
3132 Note that we are only required to do so for static tables in
3133 order to be compatible with the C++ ABI, but Ada 2005 allows
3134 to extend library level tagged types at the local level so
3135 we do it in the non-static case as well. */
3138 {
3142 }
3144 /* ... fall through ... */
3147 /* If we are not defining this entity, and we have incomplete
3148 entities being processed above us, make a dummy type and
3149 fill it in later. */
3151 {
3155 gnu_type
3156 = build_pointer_type
3171 }
3173 /* ... fall through ... */
3180 {
3183 bool is_from_limited_with
3187 /* Get the "full view" of this entity. If this is an incomplete
3188 entity from a limited with, treat its non-limited view as the full
3189 view. Otherwise, if this is an incomplete or private type, use the
3190 full view. In the former case, we might point to a private type,
3191 in which case, we need its full view. Also, we want to look at the
3192 actual type used for the representation, so this takes a total of
3193 three steps. */
3194 Entity_Id gnat_desig_full_direct_first
3198 Entity_Id gnat_desig_full_direct
3199 = ((is_from_limited_with
3204 Entity_Id gnat_desig_full
3207 /* This the type actually used to represent the designated type,
3208 either gnat_desig_full or gnat_desig_equiv. */
3209 Entity_Id gnat_desig_rep;
3211 /* Nonzero if this is a pointer to an unconstrained array. */
3214 /* We want to know if we'll be seeing the freeze node for any
3215 incomplete type we may be pointing to. */
3216 bool in_main_unit
3221 /* Nonzero if we make a dummy type here. */
3223 /* Nonzero if the dummy is a fat pointer. */
3231 /* If either the designated type or its full view is an unconstrained
3232 array subtype, replace it with the type it's a subtype of. This
3233 avoids problems with multiple copies of unconstrained array types.
3234 Likewise, if the designated type is a subtype of an incomplete
3235 record type, use the parent type to avoid order of elaboration
3236 issues. This can lose some code efficiency, but there is no
3237 alternative. */
3248 /* Now set the type that actually marks the representation of
3249 the designated type and also flag whether we have a unconstrained
3250 array. */
3252 is_unconstrained_array
3256 /* If we are pointing to an incomplete type whose completion is an
3257 unconstrained array, make a fat pointer type. The two types in our
3258 fields will be pointers to dummy nodes and will be replaced in
3259 update_pointer_to. Similarly, if the type itself is a dummy type or
3260 an unconstrained array. Also make a dummy TYPE_OBJECT_RECORD_TYPE
3261 in case we have any thin pointers to it. */
3272 {
3273 tree gnu_old
3277 tree fields;
3279 /* Show the dummy we get will be a fat pointer. */
3282 /* If the call above got something that has a pointer, that
3283 pointer is our type. This could have happened either
3284 because the type was elaborated or because somebody
3285 else executed the code below. */
3288 {
3309 fields
3311 create_field_decl
3313 gnu_ptr_array,
3316 gnu_ptr_template,
3319 /* Make sure we can place this into a register. */
3324 /* Do not finalize this record type since the types of
3325 its fields are incomplete. */
3333 }
3334 }
3336 /* If we already know what the full type is, use it. */
3341 /* Get the type of the thing we are to point to and build a pointer
3342 to it. If it is a reference to an incomplete or private type with a
3343 full view that is a record, make a dummy type node and get the
3344 actual type later when we have verified it is safe. */
3350 /* Likewise if we are pointing to a record or array and we
3351 are to defer elaborating incomplete types. We do this
3352 since this access type may be the full view of some
3353 private type. Note that the unconstrained array case is
3354 handled above. */
3360 /* If this is a reference from a limited_with type back to our
3361 main unit and there's a Freeze_Node for it, either we have
3362 already processed the declaration and made the dummy type,
3363 in which case we just reuse the latter, or we have not yet,
3364 in which case we make the dummy type and it will be reused
3365 when the declaration is processed. In both cases, the
3366 pointer eventually created below will be automatically
3367 adjusted when the Freeze_Node is processed. Note that the
3368 unconstrained array case is handled above. */
3371 {
3374 }
3376 /* Otherwise handle the case of a pointer to itself. */
3378 {
3379 gnu_type
3383 }
3385 /* If expansion is disabled, the equivalent type of a concurrent
3386 type is absent, so build a dummy pointer type. */
3390 /* Finally, handle the straightforward case where we can just
3391 elaborate our designated type and point to it. */
3392 else
3395 /* It is possible that a call to gnat_to_gnu_type above resolved our
3396 type. If so, just return it. */
3398 {
3401 }
3403 /* If we have a GCC type for the designated type, possibly modify it
3404 if we are pointing only to constant objects and then make a pointer
3405 to it. Don't do this for unconstrained arrays. */
3407 {
3410 {
3411 gnu_desig_type
3412 = build_qualified_type
3416 /* Some extra processing is required if we are building a
3417 pointer to an incomplete type (in the GCC sense). We might
3418 have such a type if we just made a dummy, or directly out
3419 of the call to gnat_to_gnu_type above if we are processing
3420 an access type for a record component designating the
3421 record type itself. */
3423 {
3424 /* We must ensure that the pointer to variant we make will
3425 be processed by update_pointer_to when the initial type
3426 is completed. Pretend we made a dummy and let further
3427 processing act as usual. */
3430 /* We must ensure that update_pointer_to will not retrieve
3431 the dummy variant when building a properly qualified
3432 version of the complete type. We take advantage of the
3433 fact that get_qualified_type is requiring TYPE_NAMEs to
3434 match to influence build_qualified_type and then also
3435 update_pointer_to here. */
3438 }
3439 }
3441 gnu_type
3444 }
3446 /* If we are not defining this object and we made a dummy pointer,
3447 save our current definition, evaluate the actual type, and replace
3448 the tentative type we made with the actual one. If we are to defer
3449 actually looking up the actual type, make an entry in the
3450 deferred list. If this is from a limited with, we have to defer
3451 to the end of the current spec in two cases: first if the
3452 designated type is in the current unit and second if the access
3453 type is. */
3455 {
3456 tree gnu_old_type
3462 gnu_type
3463 = build_pointer_type
3464 (TYPE_OBJECT_RECORD_TYPE
3476 && ! (is_from_limited_with
3477 && (in_main_unit
3482 /* Note that the call to gnat_to_gnu_type here might have
3483 updated gnu_old_type directly, in which case it is not a
3484 dummy type any more when we get into update_pointer_to.
3486 This may happen for instance when the designated type is a
3487 record type, because their elaboration starts with an
3488 initial node from make_dummy_type, which may yield the same
3489 node as the one we got.
3491 Besides, variants of this non-dummy type might have been
3492 created along the way. update_pointer_to is expected to
3493 properly take care of those situations. */
3494 else
3495 {
3500 = (is_from_limited_with
3501 && (in_main_unit
3509 }
3510 }
3511 }
3518 else
3519 {
3520 /* The runtime representation is the equivalent type. */
3523 }
3536 /* We treat this as identical to its base type; any constraint is
3537 meaningful only to the front end.
3539 The designated type must be elaborated as well, if it does
3540 not have its own freeze node. Designated (sub)types created
3541 for constrained components of records with discriminants are
3542 not frozen by the front end and thus not elaborated by gigi,
3543 because their use may appear before the base type is frozen,
3544 and because it is not clear that they are needed anywhere in
3545 Gigi. With the current model, there is no correct place where
3546 they could be elaborated. */
3553 {
3554 /* If we are not defining this entity, and we have incomplete
3555 entities being processed above us, make a dummy type and
3556 elaborate it later. */
3558 {
3561 tree gnu_ptr_type
3562 = build_pointer_type
3569 }
3572 Incomplete_Or_Private_Kind))
3575 }
3580 /* Subprogram Entities
3582 The following access functions are defined for subprograms (functions
3583 or procedures):
3585 First_Formal The first formal parameter.
3586 Is_Imported Indicates that the subprogram has appeared in
3587 an INTERFACE or IMPORT pragma. For now we
3588 assume that the external language is C.
3589 Is_Exported Likewise but for an EXPORT pragma.
3590 Is_Inlined True if the subprogram is to be inlined.
3592 In addition for function subprograms we have:
3594 Etype Return type of the function.
3596 Each parameter is first checked by calling must_pass_by_ref on its
3597 type to determine if it is passed by reference. For parameters which
3598 are copied in, if they are Ada In Out or Out parameters, their return
3599 value becomes part of a record which becomes the return type of the
3600 function (C function - note that this applies only to Ada procedures
3601 so there is no Ada return type). Additional code to store back the
3602 parameters will be generated on the caller side. This transformation
3603 is done here, not in the front-end.
3605 The intended result of the transformation can be seen from the
3606 equivalent source rewritings that follow:
3608 struct temp {int a,b};
3609 procedure P (A,B: In Out ...) is temp P (int A,B)
3610 begin {
3611 .. ..
3612 end P; return {A,B};
3613 }
3615 temp t;
3616 P(X,Y); t = P(X,Y);
3617 X = t.a , Y = t.b;
3619 For subprogram types we need to perform mainly the same conversions to
3620 GCC form that are needed for procedures and function declarations. The
3621 only difference is that at the end, we make a type declaration instead
3622 of a function declaration. */
3627 {
3628 /* The first GCC parameter declaration (a PARM_DECL node). The
3629 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3630 actually is the head of this parameter list. */
3632 /* Likewise for the stub associated with an exported procedure. */
3634 /* The type returned by a function. If the subprogram is a procedure
3635 this type should be void_type_node. */
3637 /* List of fields in return type of procedure with copy-in copy-out
3638 parameters. */
3640 /* Non-null for subprograms containing parameters passed by copy-in
3641 copy-out (Ada In Out or Out parameters not passed by reference),
3642 in which case it is the list of nodes used to specify the values of
3643 the in out/out parameters that are returned as a record upon
3644 procedure return. The TREE_PURPOSE of an element of this list is
3645 a field of the record and the TREE_VALUE is the PARM_DECL
3646 corresponding to that field. This list will be saved in the
3647 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3649 /* If an import pragma asks to map this subprogram to a GCC builtin,
3650 this is the builtin DECL node. */
3652 /* For the stub associated with an exported procedure. */
3655 Entity_Id gnat_param;
3658 bool extern_flag
3670 /* A parameter may refer to this type, so defer completion
3671 of any incomplete types. */
3674 /* If the subprogram has an alias, it is probably inherited, so
3675 we can use the original one. If the original "subprogram"
3676 is actually an enumeration literal, it may be the first use
3677 of its type, so we must elaborate that type now. */
3679 {
3686 /* Elaborate any Itypes in the parameters of this entity. */
3694 }
3696 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3697 corresponding DECL node.
3699 We still want the parameter associations to take place because the
3700 proper generation of calls depends on it (a GNAT parameter without
3701 a corresponding GCC tree has a very specific meaning), so we don't
3702 just break here. */
3706 /* ??? What if we don't find the builtin node above ? warn ? err ?
3707 In the current state we neither warn nor err, and calls will just
3708 be handled as for regular subprograms. */
3713 /* If this function returns by reference, make the actual
3714 return type of this function the pointer and mark the decl. */
3716 {
3719 }
3721 /* If the Mechanism is By_Reference, ensure the return type uses
3722 the machine's by-reference mechanism, which may not the same
3723 as above (e.g., it might be by passing a fake parameter). */
3726 {
3729 /* We expect this bit to be reset by gigi shortly, so can avoid a
3730 type node copy here. This actually also prevents troubles with
3731 the generation of debug information for the function, because
3732 we might have issued such info for this type already, and would
3733 be attaching a distinct type node to the function if we made a
3734 copy here. */
3735 }
3737 /* If we are supposed to return an unconstrained array,
3738 actually return a fat pointer and make a note of that. Return
3739 a pointer to an unconstrained record of variable size. */
3741 {
3744 }
3746 /* If the type requires a transient scope, the result is allocated
3747 on the secondary stack, so the result type of the function is
3748 just a pointer. */
3750 {
3753 }
3755 /* If the type is a padded type and the underlying type would not
3756 be passed by reference or this function has a foreign convention,
3757 return the underlying type. */
3765 /* If the return type has a non-constant size, we convert the function
3766 into a procedure and its caller will pass a pointer to an object as
3767 the first parameter when we call the function. This can happen for
3768 an unconstrained type with a maximum size or a constrained type with
3769 a size not known at compile time. */
3772 {
3774 gnu_param_list
3779 }
3781 /* If the return type has a size that overflows, we cannot have
3782 a function that returns that type. This usage doesn't make
3783 sense anyway, so give an error here. */
3787 {
3789 gnat_entity);
3795 }
3797 /* Look at all our parameters and get the type of
3798 each. While doing this, build a copy-out structure if
3799 we need one. */
3801 /* Loop over the parameters and get their associated GCC tree.
3802 While doing this, build a copy-out structure if we need one. */
3806 {
3813 /* Builtins are expanded inline and there is no real call sequence
3814 involved. So the type expected by the underlying expander is
3815 always the type of each argument "as is". */
3818 /* Handle the first parameter of a valued procedure specially. */
3821 /* Otherwise, see if a Mechanism was supplied that forced this
3822 parameter to be passed one way or another. */
3825 ;
3829 {
3833 mech))
3835 else
3837 }
3838 else
3839 {
3842 }
3844 gnu_param
3849 /* We are returned either a PARM_DECL or a type if no parameter
3850 needs to be passed; in either case, adjust the type. */
3853 else
3854 {
3857 }
3860 {
3861 /* If it's an exported subprogram, we build a parameter list
3862 in parallel, in case we need to emit a stub for it. */
3864 {
3865 gnu_stub_param_list
3867 /* Change By_Descriptor parameter to By_Reference for
3868 the internal version of an exported subprogram. */
3870 {
3871 gnu_param
3876 }
3877 else
3879 }
3886 /* If a parameter is a pointer, this function may modify
3887 memory through it and thus shouldn't be considered
3888 a pure function. Also, the memory may be modified
3889 between two calls, so they can't be CSE'ed. The latter
3890 case also handles by-ref parameters. */
3894 }
3897 {
3899 {
3904 }
3913 gnu_return_list);
3914 }
3915 }
3917 /* Do not compute record for out parameters if subprogram is
3918 stubbed since structures are incomplete for the back-end. */
3923 /* If we have a CICO list but it has only one entry, we convert
3924 this function into a function that simply returns that one
3925 object. */
3930 prepend_one_attribute_to
3933 gnat_entity);
3935 /* The lists have been built in reverse. */
3945 gnu_type
3951 gnu_stub_type
3956 /* A subprogram (something that doesn't return anything) shouldn't
3957 be considered Pure since there would be no reason for such a
3958 subprogram. Note that procedures with Out (or In Out) parameters
3959 have already been converted into a function with a return type. */
3963 /* The semantics of "pure" in Ada essentially matches that of "const"
3964 in the back-end. In particular, both properties are orthogonal to
3965 the "nothrow" property. But this is true only if the EH circuitry
3966 is explicit in the internal representation of the back-end. If we
3967 are to completely hide the EH circuitry from it, we need to declare
3968 that calls to pure Ada subprograms that can throw have side effects
3969 since they can trigger an "abnormal" transfer of control flow; thus
3970 they can be neither "const" nor "pure" in the back-end sense. */
3971 gnu_type
3981 gnu_stub_type
3988 /* If we have a builtin decl for that function, check the signatures
3989 compatibilities. If the signatures are compatible, use the builtin
3990 decl. If they are not, we expect the checker predicate to have
3991 posted the appropriate errors, and just continue with what we have
3992 so far. */
3994 {
3998 {
4002 }
4003 }
4005 /* If there was no specified Interface_Name and the external and
4006 internal names of the subprogram are the same, only use the
4007 internal name to allow disambiguation of nested subprograms. */
4011 /* If we are defining the subprogram and it has an Address clause
4012 we must get the address expression from the saved GCC tree for the
4013 subprogram if it has a Freeze_Node. Otherwise, we elaborate
4014 the address expression here since the front-end has guaranteed
4015 in that case that the elaboration has no effects. If there is
4016 an Address clause and we are not defining the object, just
4017 make it a constant. */
4019 {
4023 gnu_address
4030 /* Convert the type of the object to a reference type that can
4031 alias everything as per 13.3(19). */
4032 gnu_type
4037 gnu_decl
4042 }
4048 else
4049 {
4051 {
4055 }
4061 gnat_entity);
4063 {
4064 tree gnu_stub_decl
4069 gnat_entity);
4071 }
4073 /* This is unrelated to the stub built right above. */
4076 }
4077 }
4088 {
4089 /* Get the "full view" of this entity. If this is an incomplete
4090 entity from a limited with, treat its non-limited view as the
4091 full view. Otherwise, use either the full view or the underlying
4092 full view, whichever is present. This is used in all the tests
4093 below. */
4094 Entity_Id full_view
4102 /* If this is an incomplete type with no full view, it must be a Taft
4103 Amendment type, in which case we return a dummy type. Otherwise,
4104 just get the type from its Etype. */
4106 {
4109 else
4110 {
4114 }
4116 }
4118 /* If we already made a type for the full view, reuse it. */
4120 {
4123 }
4125 /* Otherwise, if we are not defining the type now, get the type
4126 from the full view. But always get the type from the full view
4127 for define on use types, since otherwise we won't see them! */
4133 {
4137 }
4139 /* For incomplete types, make a dummy type entry which will be
4140 replaced later. */
4143 /* Save this type as the full declaration's type so we can do any
4144 needed updates when we see it. */
4150 }
4152 /* Simple class_wide types are always viewed as their root_type
4153 by Gigi unless an Equivalent_Type is specified. */
4165 else
4177 /* Nothing at all to do here, so just return an ERROR_MARK and claim
4178 we've already saved it, so we don't try to. */
4185 }
4187 /* If we had a case where we evaluated another type and it might have
4188 defined this one, handle it here. */
4190 {
4193 }
4195 /* If we are processing a type and there is either no decl for it or
4196 we just made one, do some common processing for the type, such as
4197 handling alignment and possible padding. */
4200 {
4208 /* ??? Don't set the size for a String_Literal since it is either
4209 confirming or we don't handle it properly (if the low bound is
4210 non-constant). */
4216 /* If a size was specified, see if we can make a new type of that size
4217 by rearranging the type, for example from a fat to a thin pointer. */
4219 {
4220 gnu_type
4227 }
4229 /* If the alignment hasn't already been processed and this is
4230 not an unconstrained array, see if an alignment is specified.
4231 If not, we pick a default alignment for atomic objects. */
4233 ;
4235 {
4239 /* Warn on suspiciously large alignments. This should catch
4240 errors about the (alignment,byte)/(size,bit) discrepancy. */
4242 {
4243 tree size;
4245 /* If a size was specified, take it into account. Otherwise
4246 use the RM size for records as the type size has already
4247 been adjusted to the alignment. */
4255 else
4258 /* Consider an alignment as suspicious if the alignment/size
4259 ratio is greater or equal to the byte/bit ratio. */
4264 gnat_entity);
4265 }
4266 }
4277 /* See if we need to pad the type. If we did, and made a record,
4278 the name of the new type may be changed. So get it back for
4279 us when we make the new TYPE_DECL below. */
4286 {
4290 }
4294 /* If we are at global level, GCC will have applied variable_size to
4295 the type, but that won't have done anything. So, if it's not
4296 a constant or self-referential, call elaborate_expression_1 to
4297 make a variable for the size rather than calculating it each time.
4298 Handle both the RM size and the actual size. */
4303 {
4307 {
4314 }
4315 else
4316 {
4323 /* ??? For now, store the size as a multiple of the alignment
4324 in bytes so that we can see the alignment from the tree. */
4326 = build_binary_op
4328 elaborate_expression_1
4339 SET_TYPE_ADA_SIZE
4342 gnat_entity,
4346 }
4347 }
4349 /* If this is a record type or subtype, call elaborate_expression_1 on
4350 any field position. Do this for both global and local types.
4351 Skip any fields that we haven't made trees for to avoid problems with
4352 class wide types. */
4357 {
4360 /* ??? Unfortunately, GCC needs to be able to prove the
4361 alignment of this offset and if it's a variable, it can't.
4362 In GCC 3.4, we'll use DECL_OFFSET_ALIGN in some way, but
4363 right now, we have to put in an explicit multiply and
4364 divide by that value. */
4366 {
4368 = build_binary_op
4370 elaborate_expression_1
4380 /* ??? The context of gnu_field is not necessarily gnu_type so
4381 the MULT_EXPR node built above may not be marked by the call
4382 to create_type_decl below. */
4385 }
4386 }
4390 | (TYPE_QUAL_VOLATILE
4406 else
4408 }
4411 {
4414 /* Back-annotate the Alignment of the type if not already in the
4415 tree. Likewise for sizes. */
4421 {
4422 /* If the size is self-referential, we annotate the maximum
4423 value of that size. */
4432 {
4433 /* In this mode the tag and the parent components are not
4434 generated by the front-end, so the sizes must be adjusted
4435 explicitly now. */
4439 {
4440 size_offset
4444 }
4445 else
4453 }
4454 }
4458 }
4468 /* If we haven't already, associate the ..._DECL node that we just made with
4469 the input GNAT entity node. */
4473 /* If this is an enumeral or floating-point type, we were not able to set
4474 the bounds since they refer to the type. These bounds are always static.
4476 For enumeration types, also write debugging information and declare the
4477 enumeration literal table, if needed. */
4481 {
4484 /* If this is a padded type, we need to use the underlying type. */
4489 /* If this is a floating point type and we haven't set a floating
4490 point type yet, use this in the evaluation of the bounds. */
4500 {
4501 /* Since this has both a typedef and a tag, avoid outputting
4502 the name twice. */
4505 }
4506 }
4508 /* If we deferred processing of incomplete types, re-enable it. If there
4509 were no other disables and we have some to process, do so. */
4511 {
4513 {
4516 /* We are back to level 0 for the deferring of incomplete types.
4517 But processing these incomplete types below may itself require
4518 deferring, so preserve what we have and restart from scratch. */
4522 /* For finalization, however, all types must be complete so we
4523 cannot do the same because deferred incomplete types may end up
4524 referencing each other. Process them all recursively first. */
4525 defer_finalize_level++;
4528 {
4535 }
4537 defer_finalize_level--;
4538 }
4540 /* All the deferred incomplete types have been processed so we can
4541 now proceed with the finalization of the deferred types. */
4543 {
4545 tree t;
4551 }
4552 }
4554 /* If we are not defining this type, see if it's in the incomplete list.
4555 If so, handle that list entry now. */
4557 {
4562 {
4566 }
4567 }
4570 force_global--;
4579 }
4581 /* Similar, but if the returned value is a COMPONENT_REF, return the
4582 FIELD_DECL. */
4584 tree
4586 {
4593 }
4595 /* Wrap up compilation of DECL, a TYPE_DECL, possibly deferring it.
4596 Every TYPE_DECL generated for a type definition must be passed
4597 to this function once everything else has been done for it. */
4599 void
4601 {
4602 /* We need to defer finalizing the type if incomplete types
4603 are being deferred or if they are being processed. */
4606 else
4608 }
4610 /* Same as above but without deferring the compilation. This
4611 function should not be invoked directly on a TYPE_DECL. */
4613 static void
4615 {
4621 /* Now process all the variants. This is needed for STABS. */
4623 {
4628 {
4631 }
4634 }
4635 }
4637 /* Finalize any From_With_Type incomplete types. We do this after processing
4638 our compilation unit and after processing its spec, if this is a body. */
4640 void
4642 {
4648 {
4655 }
4656 }
4658 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
4659 kind of type (such E_Task_Type) that has a different type which Gigi
4660 uses for its representation. If the type does not have a special type
4661 for its representation, return GNAT_ENTITY. If a type is supposed to
4662 exist, but does not, abort unless annotating types, in which case
4663 return Empty. If GNAT_ENTITY is Empty, return Empty. */
4665 Entity_Id
4667 {
4674 {
4700 }
4704 }
4706 /* Return a GCC tree for a parameter corresponding to GNAT_PARAM and
4707 using MECH as its passing mechanism, to be placed in the parameter
4708 list built for GNAT_SUBPROG. Assume a foreign convention for the
4709 latter if FOREIGN is true. Also set CICO to true if the parameter
4710 must use the copy-in copy-out implementation mechanism.
4712 The returned tree is a PARM_DECL, except for those cases where no
4713 parameter needs to be actually passed to the subprogram; the type
4714 of this "shadow" parameter is then returned instead. */
4716 static tree
4719 {
4723 /* The parameter can be indirectly modified if its address is taken. */
4726 tree gnu_param;
4728 /* Copy-return is used only for the first parameter of a valued procedure.
4729 It's a copy mechanism for which a parameter is never allocated. */
4731 {
4735 }
4737 /* If this is either a foreign function or if the underlying type won't
4738 be passed by reference, strip off possible padding type. */
4741 {
4745 || foreign
4749 }
4751 /* If this is a read-only parameter, make a variant of the type that is
4752 read-only. ??? However, if this is an unconstrained array, that type
4753 can be very complex, so skip it for now. Likewise for any other
4754 self-referential type. */
4762 /* For foreign conventions, pass arrays as pointers to the element type.
4763 First check for unconstrained array and get the underlying array. */
4765 gnu_param_type
4768 /* VMS descriptors are themselves passed by reference. */
4770 gnu_param_type
4773 gnat_subprog));
4775 /* Arrays are passed as pointers to element type for foreign conventions. */
4779 {
4780 /* Strip off any multi-dimensional entries, then strip
4781 off the last array to get the component type. */
4795 }
4797 /* Fat pointers are passed as thin pointers for foreign conventions. */
4799 gnu_param_type
4802 /* If we must pass or were requested to pass by reference, do so.
4803 If we were requested to pass by copy, do so.
4804 Otherwise, for foreign conventions, pass In Out or Out parameters
4805 or aggregates by reference. For COBOL and Fortran, pass all
4806 integer and FP types that way too. For Convention Ada, use
4807 the standard Ada default. */
4811 && ((foreign
4813 || (foreign
4818 || (!foreign
4820 {
4823 }
4825 /* Pass In Out or Out parameters using copy-in copy-out mechanism. */
4832 /* If this is an Out parameter that isn't passed by reference and isn't
4833 a pointer or aggregate, we don't make a PARM_DECL for it. Instead,
4834 it will be a VAR_DECL created when we process the procedure, so just
4835 return its type. For the special parameter of a valued procedure,
4836 never pass it in.
4838 An exception is made to cover the RM-6.4.1 rule requiring "by copy"
4839 Out parameters with discriminants or implicit initial values to be
4840 handled like In Out parameters. These type are normally built as
4841 aggregates, hence passed by reference, except for some packed arrays
4842 which end up encoded in special integer types.
4844 The exception we need to make is then for packed arrays of records
4845 with discriminants or implicit initial values. We have no light/easy
4846 way to check for the latter case, so we merely check for packed arrays
4847 of records. This may lead to useless copy-in operations, but in very
4848 rare cases only, as these would be exceptions in a set of already
4849 exceptional situations. */
4851 && !by_ref
4852 && (by_return
4869 /* If no Mechanism was specified, indicate what we're using, then
4870 back-annotate it. */
4876 }
4878 /* Return true if DISCR1 and DISCR2 represent the same discriminant. */
4880 static bool
4882 {
4889 return
4891 }
4893 /* Return true if the array type specified by GNAT_TYPE and GNU_TYPE has
4894 a non-aliased component in the back-end sense. */
4896 static bool
4898 {
4899 /* If the type below this is a multi-array type, then
4900 this does not have aliased components. */
4909 }
4910 \f
4911 /* Given GNAT_ENTITY, elaborate all expressions that are required to
4912 be elaborated at the point of its definition, but do nothing else. */
4914 void
4916 {
4918 {
4925 {
4929 /* ??? Tests for avoiding static constraint error expression
4930 is needed until the front stops generating bogus conversions
4931 on bounds of real types. */
4940 }
4943 {
4947 /* If this is a record extension, go a level further to find the
4948 record definition. */
4951 }
4961 {
4962 Node_Id gnat_discriminant_expr;
4963 Entity_Id gnat_field;
4966 gnat_discriminant_expr
4971 /* ??? For now, ignore access discriminants. */
4974 gnat_entity,
4976 }
4979 }
4980 }
4981 \f
4982 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
4983 any entities on its entity chain similarly. */
4985 void
4987 {
4988 Entity_Id gnat_sub_entity;
4991 /* If this has an entity list, process all in the list. */
5008 /* Now clear this if it has been defined, but only do so if it isn't
5009 a subprogram or parameter. We could refine this, but it isn't
5010 worth it. If this is statically allocated, it is supposed to
5011 hang around out of cope. */
5014 {
5017 }
5018 }
5019 \f
5020 /* Set the alias set of GNU_NEW_TYPE to be that of GNU_OLD_TYPE. If this
5021 is a multi-dimensional array type, do this recursively. */
5023 static void
5025 {
5026 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
5027 of a one-dimensional array, since the padding has the same alias set
5028 as the field type, but if it's a multi-dimensional array, we need to
5029 see the inner types. */
5035 /* We need to be careful here in case GNU_OLD_TYPE is an unconstrained
5036 array. In that case, it doesn't have the same shape as GNU_NEW_TYPE,
5037 so we need to go down to what does. */
5039 gnu_old_type
5049 }
5050 \f
5051 /* Return a TREE_LIST describing the substitutions needed to reflect
5052 discriminant substitutions from GNAT_SUBTYPE to GNAT_TYPE and add
5053 them to GNU_LIST. If GNAT_TYPE is not specified, use the base type
5054 of GNAT_SUBTYPE. The substitutions can be in any order. TREE_PURPOSE
5055 gives the tree for the discriminant and TREE_VALUES is the replacement
5056 value. They are in the form of operands to substitute_in_expr.
5057 DEFINITION is as in gnat_to_gnu_entity. */
5059 static tree
5062 {
5063 Entity_Id gnat_discrim;
5064 Node_Id gnat_value;
5075 /* Ignore access discriminants. */
5078 elaborate_expression
5082 gnu_list);
5085 }
5086 \f
5087 /* Return true if the size represented by GNU_SIZE can be handled by an
5088 allocation. If STATIC_P is true, consider only what can be done with a
5089 static allocation. */
5091 static bool
5093 {
5094 HOST_WIDE_INT our_size;
5096 /* If this is not a static allocation, the only case we want to forbid
5097 is an overflowing size. That will be converted into a raise a
5098 Storage_Error. */
5103 /* Otherwise, we need to deal with both variable sizes and constant
5104 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
5105 since assemblers may not like very large sizes. */
5111 }
5112 \f
5113 /* Prepend to ATTR_LIST an entry for an attribute with provided TYPE,
5114 NAME, ARGS and ERROR_POINT. */
5116 static void
5119 tree attr_name,
5120 tree attr_args,
5121 Node_Id attr_error_point)
5122 {
5132 }
5134 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
5136 static void
5138 {
5139 Node_Id gnat_temp;
5144 {
5153 {
5155 (gnat_to_gnu
5162 (gnat_to_gnu
5163 (Expression
5166 }
5169 {
5196 }
5199 /* Prepend to the list now. Make a list of the argument we might
5200 have, as GCC expects it. */
5201 prepend_one_attribute_to
5208 }
5209 }
5210 \f
5211 /* Get the unpadded version of a GNAT type. */
5213 tree
5215 {
5222 }
5223 \f
5224 /* Called when we need to protect a variable object using a save_expr. */
5226 tree
5228 {
5235 {
5243 }
5244 else
5246 }
5247 \f
5248 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
5249 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
5250 return the GCC tree to use for that expression. GNU_NAME is the
5251 qualification to use if an external name is appropriate and DEFINITION is
5252 nonzero if this is a definition of GNAT_ENTITY. If NEED_VALUE is nonzero,
5253 we need a result. Otherwise, we are just elaborating this for
5254 side-effects. If NEED_DEBUG is nonzero we need the symbol for debugging
5255 purposes even if it isn't needed for code generation. */
5257 static tree
5261 {
5262 tree gnu_expr;
5264 /* If we already elaborated this expression (e.g., it was involved
5265 in the definition of a private type), use the old value. */
5269 /* If we don't need a value and this is static or a discriminant, we
5270 don't need to do anything. */
5277 /* Otherwise, convert this tree to its GCC equivalent. */
5278 gnu_expr
5282 /* Save the expression in case we try to elaborate this entity again. Since
5283 this is not a DECL, don't check it. Don't save if it's a discriminant. */
5288 }
5290 /* Similar, but take a GNU expression. */
5292 static tree
5296 {
5298 /* Skip any conversions and simple arithmetics to see if the expression
5299 is a read-only variable.
5300 ??? This really should remain read-only, but we have to think about
5301 the typing of the tree here. */
5302 tree gnu_inner_expr
5307 /* In most cases, we won't see a naked FIELD_DECL here because a
5308 discriminant reference will have been replaced with a COMPONENT_REF
5309 when the type is being elaborated. However, there are some cases
5310 involving child types where we will. So convert it to a COMPONENT_REF
5311 here. We have to hope it will be at the highest level of the
5312 expression in these cases. */
5318 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
5319 that is read-only, make a variable that is initialized to contain the
5320 bound when the package containing the definition is elaborated. If
5321 this entity is defined at top level and a bound or discriminant value
5322 isn't a constant or a reference to a discriminant, replace the bound
5323 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
5324 rely here on the fact that an expression cannot contain both the
5325 discriminant and some other variable. */
5333 /* If this is a static expression or contains a discriminant, we don't
5334 need the variable for debugging (and can't elaborate anyway if a
5335 discriminant). */
5341 /* Now create the variable if we need it. */
5343 gnu_decl
5350 /* We only need to use this variable if we are in global context since GCC
5351 can do the right thing in the local case. */
5356 else
5358 }
5359 \f
5360 /* Create a record type that contains a SIZE bytes long field of TYPE with a
5361 starting bit position so that it is aligned to ALIGN bits, and leaving at
5362 least ROOM bytes free before the field. BASE_ALIGN is the alignment the
5363 record is guaranteed to get. */
5365 tree
5368 {
5369 /* We will be crafting a record type with one field at a position set to be
5370 the next multiple of ALIGN past record'address + room bytes. We use a
5371 record placeholder to express record'address. */
5376 tree record_addr_st
5379 /* The diagram below summarizes the shape of what we manipulate:
5381 <--------- pos ---------->
5382 { +------------+-------------+-----------------+
5383 record =>{ |############| ... | field (type) |
5384 { +------------+-------------+-----------------+
5385 |<-- room -->|<- voffset ->|<---- size ----->|
5386 o o
5387 | |
5388 record_addr vblock_addr
5390 Every length is in sizetype bytes there, except "pos" which has to be
5391 set as a bit position in the GCC tree for the record. */
5404 /* Compute VOFFSET and then POS. The next byte position multiple of some
5405 alignment after some address is obtained by "and"ing the alignment minus
5406 1 with the two's complement of the address. */
5412 /* POS = (ROOM + VOFFSET) * BIT_PER_UNIT, in bitsizetype. */
5417 bitsize_unit_node);
5419 /* Craft the GCC record representation. We exceptionally do everything
5420 manually here because 1) our generic circuitry is not quite ready to
5421 handle the complex position/size expressions we are setting up, 2) we
5422 have a strong simplifying factor at hand: we know the maximum possible
5423 value of voffset, and 3) we have to set/reset at least the sizes in
5424 accordance with this maximum value anyway, as we need them to convey
5425 what should be "alloc"ated for this type.
5427 Use -1 as the 'addressable' indication for the field to prevent the
5428 creation of a bitfield. We don't need one, it would have damaging
5429 consequences on the alignment computation, and create_field_decl would
5430 make one without this special argument, for instance because of the
5431 complex position expression. */
5443 bitsize_unit_node),
5453 }
5454 \f
5455 /* Return the result of rounding T up to ALIGN. */
5459 {
5464 }
5466 /* TYPE is a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE that is being used
5467 as the field type of a packed record if IN_RECORD is true, or as the
5468 component type of a packed array if IN_RECORD is false. See if we can
5469 rewrite it either as a type that has a non-BLKmode, which we can pack
5470 tighter in the packed record case, or as a smaller type with BLKmode.
5471 If so, return the new type. If not, return the original type. */
5473 static tree
5475 {
5480 /* No point in doing anything if the size is zero. */
5486 /* Copy the name and flags from the old type to that of the new.
5487 Note that we rely on the pointer equality created here for
5488 TYPE_NAME to look through conversions in various places. */
5495 /* If we are in a record and have a small size, set the alignment to
5496 try for an integral mode. Otherwise set it to try for a smaller
5497 type with BLKmode. */
5499 {
5502 }
5503 else
5504 {
5507 /* Do not try to shrink the size if the RM size is not constant. */
5512 /* Round the RM size up to a unit boundary to get the minimal size
5513 for a BLKmode record. Give up if it's already the size. */
5521 }
5525 /* Now copy the fields, keeping the position and size as we don't want
5526 to change the layout by propagating the packedness downwards. */
5529 {
5540 /* However, for the last field in a not already packed record type
5541 that is of an aggregate type, we need to use the RM_Size in the
5542 packable version of the record type, see finish_record_type. */
5552 else
5561 SET_DECL_ORIGINAL_FIELD
5570 }
5575 /* If this is a padding record, we never want to make the size smaller
5576 than what was specified. For QUAL_UNION_TYPE, also copy the size. */
5579 {
5582 }
5583 else
5584 {
5588 }
5595 /* Try harder to get a packable type if necessary, for example
5596 in case the record itself contains a BLKmode field. */
5601 /* If neither the mode nor the size has shrunk, return the old type. */
5606 }
5607 \f
5608 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
5609 if needed. We have already verified that SIZE and TYPE are large enough.
5611 GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
5612 to issue a warning.
5614 IS_USER_TYPE is true if we must complete the original type.
5616 DEFINITION is true if this type is being defined.
5618 SAME_RM_SIZE is true if the RM_Size of the resulting type is to be set
5619 to SIZE too; otherwise, it's set to the RM_Size of the original type. */
5621 tree
5625 {
5631 /* If TYPE is a padded type, see if it agrees with any size and alignment
5632 we were given. If so, return the original type. Otherwise, strip
5633 off the padding, since we will either be returning the inner type
5634 or repadding it. If no size or alignment is specified, use that of
5635 the original padded type. */
5637 {
5654 }
5656 /* If the size is either not being changed or is being made smaller (which
5657 is not done here (and is only valid for bitfields anyway), show the size
5658 isn't changing. Likewise, clear the alignment if it isn't being
5659 changed. Then return if we aren't doing anything. */
5672 /* If requested, complete the original type and give it a name. */
5679 gnat_entity);
5681 /* We used to modify the record in place in some cases, but that could
5682 generate incorrect debugging information. So make a new record
5683 type and name. */
5701 bitsize_unit_node));
5703 /* If we are changing the alignment and the input type is a record with
5704 BLKmode and a small constant size, try to make a form that has an
5705 integral mode. This might allow the padding record to also have an
5706 integral mode, which will be much more efficient. There is no point
5707 in doing so if a size is specified unless it is also a small constant
5708 size and it is incorrect to do so if we cannot guarantee that the mode
5709 will be naturally aligned since the field must always be addressable.
5711 ??? This might not always be a win when done for a stand-alone object:
5712 since the nominal and the effective type of the object will now have
5713 different modes, a VIEW_CONVERT_EXPR will be required for converting
5714 between them and it might be hard to overcome afterwards, including
5715 at the RTL level when the stand-alone object is accessed as a whole. */
5722 && (!size
5725 {
5730 }
5732 /* Now create the field with the original size. */
5737 /* Do not finalize it until after the auxiliary record is built. */
5740 /* Set the same size for its RM_size if requested; otherwise reuse
5741 the RM_size of the original type. */
5744 /* Unless debugging information isn't being written for the input type,
5745 write a record that shows what we are a subtype of and also make a
5746 variable that indicates our size, if still variable. */
5752 {
5774 }
5778 /* If the size was widened explicitly, maybe give a warning. Take the
5779 original size as the maximum size of the input if there was an
5780 unconstrained record involved and round it up to the specified alignment,
5781 if one was specified. */
5793 {
5806 /* Generate message only for entities that come from source, since
5807 if we have an entity created by expansion, the message will be
5808 generated for some other corresponding source entity. */
5811 gnat_entity,
5818 }
5821 }
5822 \f
5823 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
5824 the value passed against the list of choices. */
5826 tree
5828 {
5829 Node_Id choice;
5830 Node_Id gnat_temp;
5835 {
5837 {
5842 /* There's no good type to use here, so we might as well use
5843 integer_type_node. */
5844 this_test
5858 this_test
5868 /* This represents either a subtype range, an enumeration
5869 literal, or a constant Ekind says which. If an enumeration
5870 literal or constant, fall through to the next case. */
5873 {
5879 this_test
5886 }
5887 /* ... fall through ... */
5892 single);
5901 }
5905 }
5908 }
5909 \f
5910 /* Adjust PACKED setting as passed to gnat_to_gnu_field for a field of
5911 type FIELD_TYPE to be placed in RECORD_TYPE. Return the result. */
5913 static int
5915 {
5916 /* If the field contains an item of variable size, we cannot pack it
5917 because we cannot create temporaries of non-fixed size in case
5918 we need to take the address of the field. See addressable_p and
5919 the notes on the addressability issues for further details. */
5923 /* If the alignment of the record is specified and the field type
5924 is over-aligned, request Storage_Unit alignment for the field. */
5926 {
5929 else
5931 }
5934 }
5936 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
5937 placed in GNU_RECORD_TYPE.
5939 PACKED is 1 if the enclosing record is packed, -1 if the enclosing
5940 record has Component_Alignment of Storage_Unit, -2 if the enclosing
5941 record has a specified alignment.
5943 DEFINITION is true if this field is for a record being defined. */
5945 static tree
5948 {
5952 bool needs_strict_alignment
5956 /* If this field requires strict alignment, we cannot pack it because
5957 it would very likely be under-aligned in the record. */
5960 else
5963 /* If a size is specified, use it. Otherwise, if the record type is packed,
5964 use the official RM size. See "Handling of Type'Size Values" in Einfo
5965 for further details. */
5972 else
5975 /* If we have a specified size that's smaller than that of the field type,
5976 or a position is specified, and the field type is also a record that's
5977 BLKmode, see if we can get either an integral mode form of the type or
5978 a smaller BLKmode form. If we can, show a size was specified for the
5979 field if there wasn't one already, so we know to make this a bitfield
5980 and avoid making things wider.
5982 Doing this is first useful if the record is packed because we may then
5983 place the field at a non-byte-aligned position and so achieve tighter
5984 packing.
5986 This is in addition *required* if the field shares a byte with another
5987 field and the front-end lets the back-end handle the references, because
5988 GCC does not handle BLKmode bitfields properly.
5990 We avoid the transformation if it is not required or potentially useful,
5991 as it might entail an increase of the field's alignment and have ripple
5992 effects on the outer record type. A typical case is a field known to be
5993 byte aligned and not to share a byte with another field.
5995 Besides, we don't even look the possibility of a transformation in cases
5996 known to be in error already, for instance when an invalid size results
5997 from a component clause. */
6003 || (gnu_size
6006 {
6007 /* See what the alternate type and size would be. */
6010 bool has_byte_aligned_clause
6015 /* Compute whether we should avoid the substitution. */
6016 bool reject
6017 /* There is no point substituting if there is no change... */
6019 /* ... nor when the field is known to be byte aligned and not to
6020 share a byte with another field. */
6021 || (has_byte_aligned_clause
6023 /* The size of an aliased field must be an exact multiple of the
6024 type's alignment, which the substitution might increase. Reject
6025 substitutions that would so invalidate a component clause when the
6026 specified position is byte aligned, as the change would have no
6027 real benefit from the packing standpoint anyway. */
6029 && has_byte_aligned_clause
6032 /* Substitute unless told otherwise. */
6034 {
6039 }
6040 }
6042 /* If we are packing the record and the field is BLKmode, round the
6043 size up to a byte boundary. */
6048 {
6053 /* Ensure the position does not overlap with the parent subtype,
6054 if there is one. */
6056 {
6057 tree gnu_parent
6063 {
6064 post_error_ne_tree
6068 }
6069 }
6071 /* If this field needs strict alignment, ensure the record is
6072 sufficiently aligned and that that position and size are
6073 consistent with the alignment. */
6075 {
6081 {
6083 post_error_ne_tree
6089 post_error_ne_tree
6095 post_error_ne_tree
6101 }
6106 {
6108 post_error_ne_num
6114 post_error_ne_num
6120 post_error_ne_num
6125 else
6129 }
6130 }
6134 }
6136 /* If the record has rep clauses and this is the tag field, make a rep
6137 clause for it as well. */
6140 {
6143 }
6145 else
6148 /* We need to make the size the maximum for the type if it is
6149 self-referential and an unconstrained type. In that case, we can't
6150 pack the field since we can't make a copy to align it. */
6152 && !gnu_size
6155 {
6158 }
6160 /* If a size is specified, adjust the field's type to it. */
6162 {
6163 /* If the field's type is justified modular, we would need to remove
6164 the wrapper to (better) meet the layout requirements. However we
6165 can do so only if the field is not aliased to preserve the unique
6166 layout and if the prescribed size is not greater than that of the
6167 packed array to preserve the justification. */
6175 gnu_field_type
6180 }
6182 /* Otherwise (or if there was an error), don't specify a position. */
6183 else
6189 /* Now create the decl for the field. */
6201 }
6202 \f
6203 /* Return true if TYPE is a type with variable size, a padding type with a
6204 field of variable size or is a record that has a field such a field. */
6206 static bool
6208 {
6209 tree field;
6229 }
6230 \f
6231 /* qsort comparer for the bit positions of two record components. */
6233 static int
6235 {
6238 const int ret
6242 }
6244 /* Return a GCC tree for a record type given a GNAT Component_List and a chain
6245 of GCC trees for fields that are in the record and have already been
6246 processed. When called from gnat_to_gnu_entity during the processing of a
6247 record type definition, the GCC nodes for the discriminants will be on
6248 the chain. The other calls to this function are recursive calls from
6249 itself for the Component_List of a variant and the chain is empty.
6251 PACKED is 1 if this is for a packed record, -1 if this is for a record
6252 with Component_Alignment of Storage_Unit, -2 if this is for a record
6253 with a specified alignment.
6255 DEFINITION is true if we are defining this record.
6257 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
6258 with a rep clause is to be added. If it is nonzero, that is all that
6259 should be done with such fields.
6261 CANCEL_ALIGNMENT, if true, means the alignment should be zeroed before
6262 laying out the record. This means the alignment only serves to force fields
6263 to be bitfields, but not require the record to be that aligned. This is
6264 used for variants.
6266 ALL_REP, if true, means a rep clause was found for all the fields. This
6267 simplifies the logic since we know we're not in the mixed case.
6269 DO_NOT_FINALIZE, if true, means that the record type is expected to be
6270 modified afterwards so it will not be sent to the back-end for finalization.
6272 UNCHECKED_UNION, if true, means that we are building a type for a record
6273 with a Pragma Unchecked_Union.
6275 The processing of the component list fills in the chain with all of the
6276 fields of the record and then the record type is finished. */
6278 static void
6283 {
6284 Node_Id component_decl;
6285 Entity_Id gnat_field;
6286 Node_Id variant_part;
6292 /* For each variable within each component declaration create a GCC field
6293 and add it to the list, skipping any pragmas in the list. */
6298 {
6303 else
6304 {
6308 /* If this is the _Tag field, put it before any discriminants,
6309 instead of after them as is the case for all other fields.
6310 Ignore field of void type if only annotating. */
6313 else
6314 {
6317 }
6318 }
6321 }
6323 /* At the end of the component list there may be a variant part. */
6326 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
6327 mutually exclusive and should go in the same memory. To do this we need
6328 to treat each variant as a record whose elements are created from the
6329 component list for the variant. So here we create the records from the
6330 lists for the variants and put them all into the QUAL_UNION_TYPE.
6331 If this is an Unchecked_Union, we make a UNION_TYPE instead or
6332 use GNU_RECORD_TYPE if there are no fields so far. */
6334 {
6336 Node_Id variant;
6338 tree gnu_var_name
6342 tree gnu_union_type;
6343 tree gnu_union_name;
6344 tree gnu_union_field;
6353 /* Reuse an enclosing union if all fields are in the variant part
6354 and there is no representation clause on the record, to match
6355 the layout of C unions. There is an associated check below. */
6360 else
6361 {
6362 gnu_union_type
6368 }
6373 {
6375 tree gnu_inner_name;
6376 tree gnu_qual;
6384 /* Set the alignment of the inner type in case we need to make
6385 inner objects into bitfields, but then clear it out
6386 so the record actually gets only the alignment required. */
6390 /* Similarly, if the outer record has a size specified and all fields
6391 have record rep clauses, we can propagate the size into the
6392 variant part. */
6394 {
6398 }
6400 /* Create the record type for the variant. Note that we defer
6401 finalizing it until after we are sure to actually use it. */
6412 /* If this is an Unchecked_Union and we have exactly one field,
6413 use this field directly to match the layout of C unions. */
6418 else
6419 {
6420 /* Deal with packedness like in gnat_to_gnu_field. */
6421 int field_packed
6424 /* Finalize the record type now. We used to throw away
6425 empty records but we no longer do that because we need
6426 them to generate complete debug info for the variant;
6427 otherwise, the union type definition will be lacking
6428 the fields associated with these empty variants. */
6433 (all_rep_and_size
6436 (all_rep_and_size
6444 }
6448 }
6450 /* Only make the QUAL_UNION_TYPE if there are any non-empty variants. */
6452 {
6454 {
6458 }
6463 /* If GNU_UNION_TYPE is our record type, it means we must have an
6464 Unchecked_Union with no fields. Verify that and, if so, just
6465 return. */
6467 {
6469 && !gnu_field_list
6472 }
6474 gnu_union_field
6476 packed,
6483 }
6484 }
6486 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
6487 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do this
6488 in a separate pass since we want to handle the discriminants but can't
6489 play with them until we've used them in debugging data above.
6491 ??? Note: if we then reorder them, debugging information will be wrong,
6492 but there's nothing that can be done about this at the moment. */
6494 {
6496 {
6501 else
6507 }
6508 else
6509 {
6512 }
6513 }
6515 /* If we have any items in our rep'ed field list, it is not the case that all
6516 the fields in the record have rep clauses, and P_REP_LIST is nonzero,
6517 set it and ignore the items. */
6521 {
6522 /* Otherwise, sort the fields by bit position and put them into their
6523 own record if we have any fields without rep clauses. */
6524 tree gnu_rep_type
6536 /* Put the fields in the list in order of increasing position, which
6537 means we start from the end. */
6540 {
6544 }
6547 {
6553 }
6554 else
6555 {
6558 }
6559 }
6566 }
6567 \f
6568 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
6569 placed into an Esize, Component_Bit_Offset, or Component_Size value
6570 in the GNAT tree. */
6572 static Uint
6574 {
6576 TCode tcode;
6582 /* See if we've already saved the value for this node. */
6584 {
6595 }
6597 /* If we do not return inside this switch, TCODE will be set to the
6598 code to use for a Create_Node operand and LEN (set above) will be
6599 the number of recursive calls for us to make. */
6602 {
6607 /* This may have come from a conversion from some smaller type,
6608 so ensure this is in bitsizetype. */
6611 /* For negative values, use NEGATE_EXPR of the supplied value. */
6613 {
6614 /* The ridiculous code below is to handle the case of the largest
6615 negative integer. */
6618 tree temp;
6621 {
6622 negative_size
6625 bitsize_one_node));
6627 }
6634 }
6641 /* This peculiar test is to make sure that the size fits in an int
6642 on machines where HOST_WIDE_INT is not "int". */
6645 else
6649 /* The only case we handle here is a simple discriminant reference. */
6657 else
6663 /* Now just list the operations we handle. */
6695 }
6697 /* Now get each of the operands that's relevant for this code. If any
6698 cannot be expressed as a repinfo node, say we can't. */
6703 {
6707 }
6711 /* Save the result in the cache. */
6713 {
6717 }
6720 }
6722 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding
6723 GCC type, set Component_Bit_Offset and Esize to the position and size
6724 used by Gigi. */
6726 static void
6728 {
6729 tree gnu_list;
6730 tree gnu_entry;
6731 Entity_Id gnat_field;
6733 /* We operate by first making a list of all fields and their positions
6734 (we can get the sizes easily at any time) by a recursive call
6735 and then update all the sizes into the tree. */
6738 BIGGEST_ALIGNMENT);
6745 {
6749 gnu_list);
6752 {
6754 {
6755 /* In this mode the tag and parent components have not been
6756 generated, so we add the appropriate offset to each
6757 component. For a component appearing in the current
6758 extension, the offset is the size of the parent. */
6761 parent_offset
6763 bitsizetype);
6764 else
6766 }
6768 Set_Component_Bit_Offset
6770 annotate_value
6775 parent_offset)));
6779 }
6782 {
6783 /* If there is no gnu_entry, this is an inherited component whose
6784 position is the same as in the parent type. */
6785 Set_Component_Bit_Offset
6790 }
6791 }
6792 }
6794 /* Scan all fields in GNU_TYPE and build entries where TREE_PURPOSE is the
6795 FIELD_DECL and TREE_VALUE a TREE_LIST with TREE_PURPOSE being the byte
6796 position and TREE_VALUE being a TREE_LIST with TREE_PURPOSE the value to be
6797 placed into DECL_OFFSET_ALIGN and TREE_VALUE the bit position. GNU_POS is
6798 to be added to the position, GNU_BITPOS to the bit position, OFFSET_ALIGN is
6799 the present value of DECL_OFFSET_ALIGN and GNU_LIST is a list of the entries
6800 so far. */
6802 static tree
6805 {
6806 tree gnu_field;
6811 {
6816 unsigned int our_offset_align
6819 gnu_result
6824 NULL_TREE),
6825 gnu_result);
6828 gnu_result
6831 our_offset_align);
6832 }
6835 }
6836 \f
6837 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
6838 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
6839 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
6840 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
6841 for the size of a field. COMPONENT_P is true if we are being called
6842 to process the Component_Size of GNAT_OBJECT. This is used for error
6843 message handling and to indicate to use the object size of GNU_TYPE.
6844 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
6845 it means that a size of zero should be treated as an unspecified size. */
6847 static tree
6850 {
6851 Node_Id gnat_error_node;
6855 /* If a type needs strict alignment, a component of this type in
6856 a packed record cannot be packed and thus uses the type size. */
6859 else
6862 /* Find the node to use for errors. */
6869 else
6872 /* Return 0 if no size was specified, either because Esize was not Present or
6873 the specified size was zero. */
6877 /* Get the size as a tree. Give an error if a size was specified, but cannot
6878 be represented as in sizetype. */
6881 {
6886 }
6888 /* Ignore a negative size since that corresponds to our back-annotation.
6889 Also ignore a zero size unless a size clause exists. */
6893 /* The size of objects is always a multiple of a byte. */
6896 {
6900 else
6904 }
6906 /* If this is an integral type or a packed array type, the front-end has
6907 verified the size, so we need not do it here (which would entail
6908 checking against the bounds). However, if this is an aliased object, it
6909 may not be smaller than the type of the object. */
6914 /* If the object is a record that contains a template, add the size of
6915 the template to the specified size. */
6920 /* Modify the size of the type to be that of the maximum size if it has a
6921 discriminant. */
6925 /* If this is an access type or a fat pointer, the minimum size is that given
6926 by the smallest integral mode that's valid for pointers. */
6928 {
6934 ;
6937 }
6939 /* If the size of the object is a constant, the new size must not be
6940 smaller. */
6944 {
6946 post_error_ne_tree
6949 else
6956 post_error_ne_tree_2
6966 }
6969 }
6970 \f
6971 /* Similarly, but both validate and process a value of RM_Size. This
6972 routine is only called for types. */
6974 static void
6976 {
6977 /* Only give an error if a Value_Size clause was explicitly given.
6978 Otherwise, we'd be duplicating an error on the Size clause. */
6979 Node_Id gnat_attr_node
6982 tree size;
6984 /* Get the size as a tree. Do nothing if none was specified, either
6985 because RM_Size was not Present or if the specified size was zero.
6986 Give an error if a size was specified, but cannot be represented as
6987 in sizetype. */
6993 {
6996 gnat_entity);
6999 }
7001 /* Ignore a negative size since that corresponds to our back-annotation.
7002 Also ignore a zero size unless a size clause exists, a Value_Size
7003 clause exists, or this is an integer type, in which case the
7004 front end will have always set it. */
7011 /* If the old size is self-referential, get the maximum size. */
7015 /* If the size of the object is a constant, the new size must not be
7016 smaller (the front end checks this for scalar types). */
7021 {
7023 post_error_ne_tree
7028 }
7030 /* Otherwise, set the RM_Size. */
7041 }
7042 \f
7043 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
7044 If TYPE is the best type, return it. Otherwise, make a new type. We
7045 only support new integral and pointer types. BIASED_P is nonzero if
7046 we are making a biased type. */
7048 static tree
7050 {
7051 tree new_type;
7055 /* If size indicates an error, just return TYPE to avoid propagating the
7056 error. Likewise if it's too large to represent. */
7062 {
7065 /* Only do something if the type is not already the proper size and is
7066 not a packed array type. */
7078 new_type
7090 /* Do something if this is a fat pointer, in which case we
7091 may need to return the thin pointer. */
7093 return
7094 build_pointer_type
7099 /* Only do something if this is a thin pointer, in which case we
7100 may need to return the fat pointer. */
7102 return
7109 }
7112 }
7113 \f
7114 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
7115 a type or object whose present alignment is ALIGN. If this alignment is
7116 valid, return it. Otherwise, give an error and return ALIGN. */
7118 static unsigned int
7120 {
7123 Node_Id gnat_error_node;
7125 /* Don't worry about checking alignment if alignment was not specified
7126 by the source program and we already posted an error for this entity. */
7130 /* Post the error on the alignment clause if any. */
7133 else
7136 /* Within GCC, an alignment is an integer, so we must make sure a value is
7137 specified that fits in that range. Also, there is an upper bound to
7138 alignments we can support/allow. */
7149 else
7150 {
7154 }
7157 }
7159 /* Return the smallest alignment not less than SIZE. */
7161 static unsigned int
7163 {
7165 }
7166 \f
7167 /* Verify that OBJECT, a type or decl, is something we can implement
7168 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
7169 if we require atomic components. */
7171 static void
7173 {
7175 Node_Id gnat_node;
7178 tree size;
7180 /* There are three case of what OBJECT can be. It can be a type, in which
7181 case we take the size, alignment and mode from the type. It can be a
7182 declaration that was indirect, in which case the relevant values are
7183 that of the type being pointed to, or it can be a normal declaration,
7184 in which case the values are of the decl. The code below assumes that
7185 OBJECT is either a type or a decl. */
7187 {
7191 }
7193 {
7197 }
7198 else
7199 {
7203 }
7205 /* Consider all floating-point types atomic and any types that that are
7206 represented by integers no wider than a machine word. */
7213 /* For the moment, also allow anything that has an alignment equal
7214 to its size and which is smaller than a word. */
7222 {
7231 }
7236 else
7239 }
7240 \f
7241 /* Check if FTYPE1 and FTYPE2, two potentially different function type nodes,
7242 have compatible signatures so that a call using one type may be safely
7243 issued if the actual target function type is the other. Return 1 if it is
7244 the case, 0 otherwise, and post errors on the incompatibilities.
7246 This is used when an Ada subprogram is mapped onto a GCC builtin, to ensure
7247 that calls to the subprogram will have arguments suitable for the later
7248 underlying builtin expansion. */
7250 static int
7252 {
7253 /* As of now, we only perform very trivial tests and consider it's the
7254 programmer's responsibility to ensure the type correctness in the Ada
7255 declaration, as in the regular Import cases.
7257 Mismatches typically result in either error messages from the builtin
7258 expander, internal compiler errors, or in a real call sequence. This
7259 should be refined to issue diagnostics helping error detection and
7260 correction. */
7262 /* Almost fake test, ensuring a use of each argument. */
7267 }
7268 \f
7269 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new
7270 type with all size expressions that contain F updated by replacing F
7271 with R. If F is NULL_TREE, always make a new RECORD_TYPE, even if
7272 nothing has changed. */
7274 tree
7276 {
7278 tree tem;
7281 {
7287 {
7296 SET_TYPE_INDEX_TYPE
7299 }
7306 {
7320 }
7334 /* Don't know how to do these yet. */
7338 {
7353 /* If we had bounded the sizes of T by a constant, bound the sizes of
7354 NEW by the same constant. */
7364 }
7369 {
7370 tree field;
7371 bool changed_field
7378 /* Start out with no fields, make new fields, and chain them
7379 in. If we haven't actually changed the type of any field,
7380 discard everything we've done and return the old type. */
7386 {
7397 /* If this is an internal field and the type of this field is
7398 a UNION_TYPE or RECORD_TYPE with no elements, ignore it. If
7399 the type just has one element, treat that as the field.
7400 But don't do this if we are processing a QUAL_UNION_TYPE. */
7405 {
7410 {
7411 tree next_new_field
7414 /* Make sure omitting the union doesn't change
7415 the layout. */
7418 }
7419 }
7426 /* If the size of the old field was set at a constant,
7427 propagate the size in case the type's size was variable.
7428 (This occurs in the case of a variant or discriminated
7429 record with a default size used as a field of another
7430 record.) */
7439 {
7445 /* Do the substitution inside the qualifier and if we find
7446 that this field will not be present, omit it. */
7451 }
7455 else
7460 /* If this is a qualified type and this field will always be
7461 present, we are done. */
7465 }
7467 /* If this used to be a qualified union type, but we now know what
7468 field will be present, make this a normal union. */
7479 /* If the size was originally a constant use it. */
7482 {
7486 }
7489 }
7493 }
7494 }
7495 \f
7496 /* Return the "RM size" of GNU_TYPE. This is the actual number of bits
7497 needed to represent the object. */
7499 tree
7501 {
7502 /* For integer types, this is the precision. For record types, we store
7503 the size explicitly. For other types, this is just the size. */
7509 /* Return the rm_size of the actual data plus the size of the template. */
7510 return
7520 else
7522 }
7523 \f
7524 /* Return an identifier representing the external name to be used for
7525 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
7526 and the specified suffix. */
7528 tree
7530 {
7539 /* A variable using the Stdcall convention (meaning we are running
7540 on a Windows box) live in a DLL. Here we adjust its name to use
7541 the jump-table, the _imp__NAME contains the address for the NAME
7542 variable. */
7545 {
7552 }
7555 }
7557 /* Return the name to be used for GNAT_ENTITY. If a type, create a
7558 fully-qualified name, possibly with type information encoding.
7559 Otherwise, return the name. */
7561 tree
7563 {
7566 }
7568 /* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
7569 string, return a new IDENTIFIER_NODE that is the concatenation of
7570 the name in GNU_ID and SUFFIX. */
7572 tree
7574 {
7582 }