| blob | bbbb471a3ae9a6592a82601da0728c25198c9c49 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2005, 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 2, 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 distributed with GNAT; see file COPYING. If not, write *
19 * to the Free Software Foundation, 51 Franklin Street, Fifth Floor, *
20 * Boston, MA 02110-1301, USA. *
21 * *
22 * GNAT was originally developed by the GNAT team at New York University. *
23 * Extensive contributions were provided by Ada Core Technologies Inc. *
24 * *
25 ****************************************************************************/
56 /* Convention_Stdcall should be processed in a specific way on Windows targets
57 only. The macro below is a helper to avoid having to check for a Windows
58 specific attribute throughout this unit. */
60 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
61 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
62 #else
63 #define Has_Stdcall_Convention(E) (0)
64 #endif
66 /* These two variables are used to defer recursively expanding incomplete
67 types while we are processing a record or subprogram type. */
70 static struct incomplete
71 {
73 tree old_type;
74 Entity_Id full_type;
77 /* These two variables are used to defer emission of debug information for
78 nested incomplete record types */
106 /* Given GNAT_ENTITY, an entity in the incoming GNAT tree, return a
107 GCC type corresponding to that entity. GNAT_ENTITY is assumed to
108 refer to an Ada type. */
110 tree
112 {
113 tree gnu_decl;
115 /* The back end never attempts to annotate generic types */
119 /* Convert the ada entity type into a GCC TYPE_DECL node. */
123 }
124 \f
125 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
126 entity, this routine returns the equivalent GCC tree for that entity
127 (an ..._DECL node) and associates the ..._DECL node with the input GNAT
128 defining identifier.
130 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
131 initial value (in GCC tree form). This is optional for variables.
132 For renamed entities, GNU_EXPR gives the object being renamed.
134 DEFINITION is nonzero if this call is intended for a definition. This is
135 used for separate compilation where it necessary to know whether an
136 external declaration or a definition should be created if the GCC equivalent
137 was not created previously. The value of 1 is normally used for a non-zero
138 DEFINITION, but a value of 2 is used in special circumstances, defined in
139 the code. */
141 tree
143 {
144 tree gnu_entity_id;
146 /* Contains the gnu XXXX_DECL tree node which is equivalent to the input
147 GNAT tree. This node will be associated with the GNAT node by calling
148 the save_gnu_tree routine at the end of the `switch' statement. */
150 /* true if we have already saved gnu_decl as a gnat association. */
152 /* Nonzero if we incremented defer_incomplete_level. */
154 /* Nonzero if we incremented defer_debug_level. */
156 /* Nonzero if we incremented force_global. */
158 /* Nonzero if we should check to see if elaborated during processing. */
160 /* Nonzero if we made GNU_DECL and its type here. */
166 Entity_Id gnat_temp;
167 unsigned int esize
177 bool imported_p
182 /* Since a use of an Itype is a definition, process it as such if it
183 is not in a with'ed unit. */
188 {
189 /* Ensure that we are in a subprogram mentioned in the Scope
190 chain of this entity, our current scope is global,
191 or that we encountered a task or entry (where we can't currently
192 accurately check scoping). */
195 {
198 }
202 {
207 gnat_temp
219 && (current_function_decl
221 {
224 }
225 }
227 /* This abort means the entity "gnat_entity" has an incorrect scope,
228 i.e. that its scope does not correspond to the subprogram in which
229 it is declared */
231 }
233 /* If this is entity 0, something went badly wrong. */
236 /* If we've already processed this entity, return what we got last time.
237 If we are defining the node, we should not have already processed it.
238 In that case, we will abort below when we try to save a new GCC tree for
239 this object. We also need to handle the case of getting a dummy type
240 when a Full_View exists. */
243 && (! definition
245 {
252 {
258 }
261 }
263 /* If this is a numeric or enumeral type, or an access type, a nonzero
264 Esize must be specified unless it was specified by the programmer. */
272 /* Likewise, RM_Size must be specified for all discrete and fixed-point
273 types. */
277 /* Get the name of the entity and set up the line number and filename of
278 the original definition for use in any decl we make. */
282 /* If we get here, it means we have not yet done anything with this
283 entity. If we are not defining it here, it must be external,
284 otherwise we should have defined it already. */
291 /* For cases when we are not defining (i.e., we are referencing from
292 another compilation unit) Public entities, show we are at global level
293 for the purpose of computing scopes. Don't do this for components or
294 discriminants since the relevant test is whether or not the record is
295 being defined. But do this for Imported functions or procedures in
296 all cases. */
304 /* Handle any attributes directly attached to the entity. */
308 /* Machine_Attributes on types are expected to be propagated to subtypes.
309 The corresponding Gigi_Rep_Items are only attached to the first subtype
310 though, so we handle the propagation here. */
317 {
319 /* If this is a use of a deferred constant, get its full
320 declaration. */
322 {
327 }
329 /* If we have an external constant that we are not defining,
330 get the expression that is was defined to represent. We
331 may throw that expression away later if it is not a
332 constant.
333 Do not retrieve the expression if it is an aggregate, because
334 in complex instantiation contexts it may not be expanded */
343 /* Ignore deferred constant definitions; they are processed fully in the
344 front-end. For deferred constant references, get the full
345 definition. On the other hand, constants that are renamings are
346 handled like variable renamings. If No_Initialization is set, this is
347 not a deferred constant but a constant whose value is built
348 manually. */
353 {
357 }
360 {
365 }
370 /* We used to special case VMS exceptions here to directly map them to
371 their associated condition code. Since this code had to be masked
372 dynamically to strip off the severity bits, this caused trouble in
373 the GCC/ZCX case because the "type" pointers we store in the tables
374 have to be static. We now don't special case here anymore, and let
375 the regular processing take place, which leaves us with a regular
376 exception data object for VMS exceptions too. The condition code
377 mapping is taken care of by the front end and the bitmasking by the
378 runtime library. */
383 {
384 /* The GNAT record where the component was defined. */
387 /* If the variable is an inherited record component (in the case of
388 extended record types), just return the inherited entity, which
389 must be a FIELD_DECL. Likewise for discriminants.
390 For discriminants of untagged records which have explicit
391 stored discriminants, return the entity for the corresponding
392 stored discriminant. Also use Original_Record_Component
393 if the record has a private extension. */
397 {
398 gnu_decl
403 }
405 /* If the enclosing record has explicit stored discriminants,
406 then it is an untagged record. If the Corresponding_Discriminant
407 is not empty then this must be a renamed discriminant and its
408 Original_Record_Component must point to the corresponding explicit
409 stored discriminant (i.e., we should have taken the previous
410 branch). */
414 {
415 /* A tagged record has no explicit stored discriminants. */
419 gnu_decl
424 }
426 /* If the enclosing record has explicit stored discriminants,
427 then it is an untagged record. If the Corresponding_Discriminant
428 is not empty then this must be a renamed discriminant and its
429 Original_Record_Component must point to the corresponding explicit
430 stored discriminant (i.e., we should have taken the first
431 branch). */
438 /* Otherwise, if we are not defining this and we have no GCC type
439 for the containing record, make one for it. Then we should
440 have made our own equivalent. */
442 {
443 /* ??? If this is in a record whose scope is a protected
444 type and we have an Original_Record_Component, use it.
445 This is a workaround for major problems in protected type
446 handling. */
454 {
455 gnu_decl
461 }
467 }
469 else
470 /* Here we have no GCC type and this is a reference rather than a
471 definition. This should never happen. Most likely the cause is a
472 reference before declaration in the gnat tree for gnat_entity. */
474 }
480 /* Simple variables, loop variables, OUT parameters, and exceptions. */
481 object:
482 {
484 bool const_flag
499 {
503 else
505 }
507 /* Get the type after elaborating the renamed object. */
510 /* If this is a loop variable, its type should be the base type.
511 This is because the code for processing a loop determines whether
512 a normal loop end test can be done by comparing the bounds of the
513 loop against those of the base type, which is presumed to be the
514 size used for computation. But this is not correct when the size
515 of the subtype is smaller than the type. */
519 /* Reject non-renamed objects whose types are unconstrained arrays or
520 any object whose type is a dummy type or VOID_TYPE. */
526 {
529 force_global--;
531 }
533 /* If an alignment is specified, use it if valid. Note that
534 exceptions are objects but don't have alignments. We must do this
535 before we validate the size, since the alignment can affect the
536 size. */
538 {
544 }
546 /* If we are defining the object, see if it has a Size value and
547 validate it if so. If we are not defining the object and a Size
548 clause applies, simply retrieve the value. We don't want to ignore
549 the clause and it is expected to have been validated already. Then
550 get the new type, if any. */
559 {
560 gnu_type
566 }
568 /* If this object has self-referential size, it must be a record with
569 a default value. We are supposed to allocate an object of the
570 maximum size in this case unless it is a constant with an
571 initializing expression, in which case we can get the size from
572 that. Note that the resulting size may still be a variable, so
573 this may end up with an indirect allocation. */
577 {
579 gnu_size
580 = SUBSTITUTE_PLACEHOLDER_IN_EXPR
583 /* We may have no GNU_EXPR because No_Initialization is
584 set even though there's an Expression. */
589 gnu_size
591 (Etype
593 else
594 {
597 }
598 }
600 /* If the size is zero bytes, make it one byte since some linkers have
601 trouble with zero-sized objects. If the object will have a
602 template, that will make it nonzero so don't bother. Also avoid
603 doing that for an object renaming or an object with an address
604 clause, as we would lose useful information on the view size
605 (e.g. for null array slices) and we are not allocating the object
606 here anyway. */
615 /* If this is an atomic object with no specified size and alignment,
616 but where the size of the type is a constant, set the alignment to
617 the lowest power of two greater than the size, or to the
618 biggest meaningful alignment, whichever is smaller. */
622 {
625 BIGGEST_ALIGNMENT))
627 else
632 }
634 /* If the object is set to have atomic components, find the component
635 type and validate it.
637 ??? Note that we ignore Has_Volatile_Components on objects; it's
638 not at all clear what to do in that case. */
641 {
650 }
652 /* Now check if the type of the object allows atomic access. Note
653 that we must test the type, even if this object has size and
654 alignment to allow such access, because we will be going
655 inside the padded record to assign to the object. We could fix
656 this by always copying via an intermediate value, but it's not
657 clear it's worth the effort. */
661 /* If this is an aliased object with an unconstrained nominal subtype,
662 make a type that includes the template. */
666 {
667 tree gnu_fat
670 gnu_type
674 }
676 #ifdef MINIMUM_ATOMIC_ALIGNMENT
677 /* If the size is a constant and no alignment is specified, force
678 the alignment to be the minimum valid atomic alignment. The
679 restriction on constant size avoids problems with variable-size
680 temporaries; if the size is variable, there's no issue with
681 atomic access. Also don't do this for a constant, since it isn't
682 necessary and can interfere with constant replacement. Finally,
683 do not do it for Out parameters since that creates an
684 size inconsistency with In parameters. */
693 #endif
695 /* Make a new type with the desired size and alignment, if needed. */
699 /* Make a volatile version of this object's type if we are to
700 make the object volatile. Note that 13.3(19) says that we
701 should treat other types of objects as volatile as well. */
711 /* Convert the expression to the type of the object except in the
712 case where the object's type is unconstrained or the object's type
713 is a padded record whose field is of self-referential size. In
714 the former case, converting will generate unnecessary evaluations
715 of the CONSTRUCTOR to compute the size and in the latter case, we
716 want to only copy the actual data. */
722 && (CONTAINS_PLACEHOLDER_P
726 /* See if this is a renaming, and handle appropriately depending on
727 what is renamed and in which context. There are three major
728 cases:
730 1/ This is a constant renaming and we can just make an object
731 with what is renamed as its initial value,
733 2/ We can reuse a stabilized version of what is renamed in place
734 of the renaming,
736 3/ If neither 1 or 2 applies, we make the renaming entity a constant
737 pointer to what is being renamed. */
740 {
741 /* If the renamed object had padding, strip off the reference
742 to the inner object and reset our type. */
746 && (TYPE_IS_PADDING_P
748 {
751 }
753 /* Case 1: If this is a constant renaming, treat it as a normal
754 object whose initial value is what is being renamed. We cannot
755 do this if the type is unconstrained or class-wide. */
762 ;
764 /* Otherwise, see if we can proceed with a stabilized version of
765 the renamed entity or if we need to make a pointer. */
766 else
767 {
771 /* Case 2: If the renaming entity need not be materialized and
772 the renamed expression is something we can stabilize, use
773 that for the renaming after forcing the evaluation of any
774 SAVE_EXPR. At the global level, we can only do this if we
775 know no SAVE_EXPRs will be made. */
780 {
781 maybe_stable_expr
786 {
791 }
793 /* The stabilization failed. Keep maybe_stable_expr
794 untouched here to let the pointer case below know
795 about that failure. */
796 }
798 /* Case 3: Make this into a constant pointer to the object we
799 are to rename and attach the object to the pointer if it is
800 an lvalue that can be stabilized.
802 From the proper scope, attached objects will be referenced
803 directly instead of indirectly via the pointer to avoid
804 subtle aliasing problems with non addressable entities.
805 They have to be stable because we must not evaluate the
806 variables in the expression every time the renaming is used.
807 They also have to be lvalues because the context in which
808 they are reused sometimes requires so. We call pointers
809 with an attached object "renaming" pointers.
811 In the rare cases where we cannot stabilize the renamed
812 object, we just make a "bare" pointer, and the renamed
813 entity is always accessed indirectly through it. */
814 {
820 /* If a previous attempt at unrestricted
821 stabilization failed, there is no point trying
822 again and we can reuse the result without
823 attaching it to the pointer. */
825 ;
827 /* Otherwise, try to stabilize now, restricting to
828 lvalues only, and attach the expression to the pointer
829 if the stabilization succeeds. */
830 else
831 {
832 maybe_stable_expr
838 /* Attaching is actually performed downstream, as soon
839 as we have a DECL for the pointer we make. */
840 }
842 gnu_expr
846 {
847 /* If the original expression had side effects, put a
848 SAVE_EXPR around this whole thing. */
853 }
857 }
858 }
859 }
861 /* If this is an aliased object whose nominal subtype is unconstrained,
862 the object is a record that contains both the template and
863 the object. If there is an initializer, it will have already
864 been converted to the right type, but we need to create the
865 template if there is no initializer. */
868 /* Beware that padding might have been introduced
869 via maybe_pad_type above. */
872 == RECORD_TYPE
873 && TYPE_CONTAINS_TEMPLATE_P
876 {
877 tree template_field
882 gnu_expr
883 = gnat_build_constructor
885 tree_cons
889 NULL_TREE),
890 NULL_TREE));
891 }
893 /* If this is a pointer and it does not have an initializing
894 expression, initialize it to NULL, unless the object is
895 imported. */
901 /* If we are defining the object and it has an Address clause we must
902 get the address expression from the saved GCC tree for the
903 object if the object has a Freeze_Node. Otherwise, we elaborate
904 the address expression here since the front-end has guaranteed
905 in that case that the elaboration has no effects. Note that
906 only the latter mechanism is currently in use. */
908 {
909 tree gnu_address
915 /* Ignore the size. It's either meaningless or was handled
916 above. */
923 /* If we don't have an initializing expression for the underlying
924 variable, the initializing expression for the pointer is the
925 specified address. Otherwise, we have to make a COMPOUND_EXPR
926 to assign both the address and the initial value. */
929 else
930 gnu_expr
932 build_binary_op
935 gnu_address),
936 gnu_expr),
937 gnu_address);
938 }
940 /* If it has an address clause and we are not defining it, mark it
941 as an indirect object. Likewise for Stdcall objects that are
942 imported. */
946 {
951 /* No point in taking the address of an initializing expression
952 that isn't going to be used. */
955 }
957 /* If we are at top level and this object is of variable size,
958 make the actual type a hidden pointer to the real type and
959 make the initializer be a memory allocation and initialization.
960 Likewise for objects we aren't defining (presumed to be
961 external references from other packages), but there we do
962 not set up an initialization.
964 If the object's size overflows, make an allocator too, so that
965 Storage_Error gets raised. Note that we will never free
966 such memory, so we presume it never will get allocated. */
971 || (gnu_size
975 {
981 /* In case this was a aliased object whose nominal subtype is
982 unconstrained, the pointer above will be a thin pointer and
983 build_allocator will automatically make the template.
985 If we have a template initializer only (that we made above),
986 pretend there is none and rely on what build_allocator creates
987 again anyway. Otherwise (if we have a full initializer), get
988 the data part and feed that to build_allocator.
990 If we are elaborating a mutable object, tell build_allocator to
991 ignore a possibly simpler size from the initializer, if any, as
992 we must allocate the maximum possible size in this case. */
995 {
1000 {
1001 gnu_alloc_type
1008 else
1009 gnu_expr
1010 = build_component_ref
1014 }
1020 gnat_entity);
1024 }
1025 else
1026 {
1029 }
1030 }
1032 /* If this object would go into the stack and has an alignment
1033 larger than the default largest alignment, make a variable
1034 to hold the "aligning type" with a modified initial value,
1035 if any, then point to it and make that the value of this
1036 variable, which is now indirect. */
1039 {
1040 tree gnu_new_type
1043 tree gnu_new_var;
1045 gnu_new_var
1051 add_stmt_with_node
1053 build_component_ref
1056 gnu_expr),
1057 gnat_entity);
1060 gnu_expr
1061 = build_unary_op
1069 }
1075 /* Convert the expression to the type of the object except in the
1076 case where the object's type is unconstrained or the object's type
1077 is a padded record whose field is of self-referential size. In
1078 the former case, converting will generate unnecessary evaluations
1079 of the CONSTRUCTOR to compute the size and in the latter case, we
1080 want to only copy the actual data. */
1086 && (CONTAINS_PLACEHOLDER_P
1090 /* If this name is external or there was a name specified, use it,
1091 unless this is a VMS exception object since this would conflict
1092 with the symbol we need to export in addition. Don't use the
1093 Interface_Name if there is an address clause (see CD30005). */
1102 /* If this is constant initialized to a static constant and the
1103 object has an aggregate type, force it to be statically
1104 allocated. */
1120 {
1123 }
1125 /* If we have an address clause and we've made this indirect, it's
1126 not enough to merely mark the type as volatile since volatile
1127 references only conflict with other volatile references while this
1128 reference must conflict with all other references. So ensure that
1129 the dereferenced value has alias set 0. */
1138 STACK_CHECK_MAX_VAR_SIZE))))
1143 gnat_entity);
1145 /* If this is a public constant or we're not optimizing and we're not
1146 making a VAR_DECL for it, make one just for export or debugger
1147 use. Likewise if the address is taken or if the object or type is
1148 aliased. */
1155 {
1156 tree gnu_corr_var
1162 }
1164 /* If this is declared in a block that contains a block with an
1165 exception handler, we must force this variable in memory to
1166 suppress an invalid optimization. */
1171 /* Back-annotate the Alignment of the object if not already in the
1172 tree. Likewise for Esize if the object is of a constant size.
1173 But if the "object" is actually a pointer to an object, the
1174 alignment and size are the same as the type, so don't back-annotate
1175 the values for the pointer. */
1182 {
1187 gnu_back_size
1192 }
1193 }
1197 /* Return a TYPE_DECL for "void" that we previously made. */
1202 /* A special case, for the types Character and Wide_Character in
1203 Standard, we do not list all the literals. So if the literals
1204 are not specified, make this an unsigned type. */
1206 {
1209 }
1211 /* Normal case of non-character type, or non-Standard character type */
1212 {
1213 /* Here we have a list of enumeral constants in First_Literal.
1214 We make a CONST_DECL for each and build into GNU_LITERAL_LIST
1215 the list to be places into TYPE_FIELDS. Each node in the list
1216 is a TREE_LIST node whose TREE_VALUE is the literal name
1217 and whose TREE_PURPOSE is the value of the literal.
1219 Esize contains the number of bits needed to represent the enumeral
1220 type, Type_Low_Bound also points to the first literal and
1221 Type_High_Bound points to the last literal. */
1223 Entity_Id gnat_literal;
1228 else
1236 {
1238 gnu_type);
1239 tree gnu_literal
1247 }
1251 /* Note that the bounds are updated at the end of this function
1252 because to avoid an infinite recursion when we get the bounds of
1253 this type, since those bounds are objects of this type. */
1254 }
1260 /* For integer types, just make a signed type the appropriate number
1261 of bits. */
1266 /* For modular types, make the unsigned type of the proper number of
1267 bits and then set up the modulus, if required. */
1268 {
1270 tree gnu_modulus;
1276 /* Find the smallest mode at least ESIZE bits wide and make a class
1277 using that mode. */
1282 ;
1288 /* Get the modulus in this type. If it overflows, assume it is because
1289 it is equal to 2**Esize. Note that there is no overflow checking
1290 done on unsigned type, so we detect the overflow by looking for
1291 a modulus of zero, which is otherwise invalid. */
1295 {
1300 }
1302 /* If we have to set TYPE_PRECISION different from its natural value,
1303 make a subtype to do do. Likewise if there is a modulus and
1304 it is not one greater than TYPE_MAX_VALUE. */
1308 {
1325 }
1326 }
1335 /* For integral subtypes, we make a new INTEGER_TYPE. Note
1336 that we do not want to call build_range_type since we would
1337 like each subtype node to be distinct. This will be important
1338 when memory aliasing is implemented.
1340 The TREE_TYPE field of the INTEGER_TYPE we make points to the
1341 parent type; this fact is used by the arithmetic conversion
1342 functions.
1344 We elaborate the Ancestor_Subtype if it is not in the current
1345 unit and one of our bounds is non-static. We do this to ensure
1346 consistent naming in the case where several subtypes share the same
1347 bounds by always elaborating the first such subtype first, thus
1348 using its name. */
1360 {
1363 }
1371 gnat_entity,
1378 gnat_entity,
1382 /* One of the above calls might have caused us to be elaborated,
1383 so don't blow up if so. */
1385 {
1388 }
1393 /* This should be an unsigned type if the lower bound is constant
1394 and non-negative or if the base type is unsigned; a signed type
1395 otherwise. */
1405 /* If the type we are dealing with is to represent a packed array,
1406 we need to have the bits left justified on big-endian targets
1407 and right justified on little-endian targets. We also need to
1408 ensure that when the value is read (e.g. for comparison of two
1409 such values), we only get the good bits, since the unused bits
1410 are uninitialized. Both goals are accomplished by wrapping the
1411 modular value in an enclosing struct. */
1413 {
1415 tree gnu_field;
1424 /* Create a stripped-down declaration of the original type, mainly
1425 for debugging. */
1429 /* Don't notify the field as "addressable", since we won't be taking
1430 it's address and it would prevent create_field_decl from making a
1431 bitfield. */
1438 }
1443 /* If this is a VAX floating-point type, use an integer of the proper
1444 size. All the operations will be handled with ASM statements. */
1446 {
1451 sizetype));
1453 }
1455 /* The type of the Low and High bounds can be our type if this is
1456 a type from Standard, so set them at the end of the function. */
1464 {
1467 }
1469 {
1496 /* One of the above calls might have caused us to be elaborated,
1497 so don't blow up if so. */
1499 {
1502 }
1505 }
1508 /* Array and String Types and Subtypes
1510 Unconstrained array types are represented by E_Array_Type and
1511 constrained array types are represented by E_Array_Subtype. There
1512 are no actual objects of an unconstrained array type; all we have
1513 are pointers to that type.
1515 The following fields are defined on array types and subtypes:
1517 Component_Type Component type of the array.
1518 Number_Dimensions Number of dimensions (an int).
1519 First_Index Type of first index. */
1523 {
1529 int firstdim
1531 int nextdim
1537 tree gnu_max_size_unit;
1539 Entity_Id gnat_ind_subtype;
1540 Entity_Id gnat_ind_base_subtype;
1541 tree gnu_template_reference;
1542 tree tem;
1550 /* Make a node for the array. If we are not defining the array
1551 suppress expanding incomplete types. */
1557 /* Build the fat pointer type. Use a "void *" object instead of
1558 a pointer to the array type since we don't have the array type
1559 yet (it will reference the fat pointer via the bounds). */
1562 ptr_void_type_node,
1565 gnu_ptr_template,
1568 /* Make sure we can put this into a register. */
1572 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1573 is the fat pointer. This will be used to access the individual
1574 fields once we build them. */
1578 gnu_template_reference
1582 /* Now create the GCC type for each index and add the fields for
1583 that index to the template. */
1585 gnat_ind_base_subtype
1591 {
1593 tree gnu_ind_subtype
1595 tree gnu_base_subtype
1597 tree gnu_base_min
1599 tree gnu_base_max
1603 /* Make the FIELD_DECLs for the minimum and maximum of this
1604 type and then make extractions of that field from the
1605 template. */
1608 gnu_ind_subtype,
1612 gnu_ind_subtype,
1621 /* We can't use build_component_ref here since the template
1622 type isn't complete yet. */
1625 NULL_TREE);
1628 NULL_TREE);
1631 /* Make a range type with the new ranges, but using
1632 the Ada subtype. Then we convert to sizetype. */
1638 /* Update the maximum size of the array, in elements. */
1639 gnu_max_size
1643 gnu_base_min)));
1647 }
1650 gnu_template_fields
1653 /* Install all the fields into the template. */
1658 /* Now make the array of arrays and update the pointer to the array
1659 in the fat pointer. Note that it is the first field. */
1663 /* Get and validate any specified Component_Size, but if Packed,
1664 ignore it since the front end will have taken care of it. */
1665 gnu_comp_size
1667 gnat_entity,
1675 /* If the component type is a RECORD_TYPE that has a self-referential
1676 size, use the maxium size. */
1682 {
1686 }
1692 /* If Component_Size is not already specified, annotate it with the
1693 size of the component. */
1703 gnu_max_size),
1707 {
1711 /* If the type below this an multi-array type, then this
1712 does not not have aliased components.
1714 ??? Otherwise, for now, we say that any component of aggregate
1715 type is addressable because the front end may take 'Reference
1716 of it. But we have to make it addressable if it must be passed
1717 by reference or it that is the default. */
1723 }
1725 /* If an alignment is specified, use it if valid. But ignore it for
1726 types that represent the unpacked base type for packed arrays. */
1729 {
1734 }
1740 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
1741 corresponding fat pointer. */
1748 /* If the maximum size doesn't overflow, use it. */
1763 /* Create a record type for the object and its template and
1764 set the template at a negative offset. */
1776 /* Give the thin pointer type a name. */
1780 gnat_entity);
1781 }
1787 /* This is the actual data type for array variables. Multidimensional
1788 arrays are implemented in the gnu tree as arrays of arrays. Note
1789 that for the moment arrays which have sparse enumeration subtypes as
1790 index components create sparse arrays, which is obviously space
1791 inefficient but so much easier to code for now.
1793 Also note that the subtype never refers to the unconstrained
1794 array type, which is somewhat at variance with Ada semantics.
1796 First check to see if this is simply a renaming of the array
1797 type. If so, the result is the array type. */
1802 else
1803 {
1806 int first_dim
1809 int next_dim
1811 Entity_Id gnat_ind_subtype;
1812 Entity_Id gnat_ind_base_subtype;
1817 tree gnu_max_size_unit;
1821 /* First create the gnu types for each index. Create types for
1822 debugging information to point to the index types if the
1823 are not integer types, have variable bounds, or are
1824 wider than sizetype. */
1827 gnat_ind_base_subtype
1833 {
1834 tree gnu_index_subtype
1836 tree gnu_min
1838 tree gnu_max
1840 tree gnu_base_subtype
1842 tree gnu_base_min
1844 tree gnu_base_max
1847 tree gnu_base_base_min
1849 tree gnu_base_base_max
1851 tree gnu_high;
1852 tree gnu_this_max;
1854 /* If the minimum and maximum values both overflow in
1855 SIZETYPE, but the difference in the original type
1856 does not overflow in SIZETYPE, ignore the overflow
1857 indications. */
1865 && (!TREE_OVERFLOW
1873 /* Similarly, if the range is null, use bounds of 1..0 for
1874 the sizetype bounds. */
1886 /* Now compute the size of this bound. We need to provide
1887 GCC with an upper bound to use but have to deal with the
1888 "superflat" case. There are three ways to do this. If we
1889 can prove that the array can never be superflat, we can
1890 just use the high bound of the index subtype. If we can
1891 prove that the low bound minus one can't overflow, we
1892 can do this as MAX (hb, lb - 1). Otherwise, we have to use
1893 the expression hb >= lb ? hb : lb - 1. */
1896 /* See if the base array type is already flat. If it is, we
1897 are probably compiling an ACVC test, but it will cause the
1898 code below to malfunction if we don't handle it specially. */
1906 /* If gnu_high is now an integer which overflowed, the array
1907 cannot be superflat. */
1914 else
1915 gnu_high
1916 = build_cond_expr
1924 /* Also compute the maximum size of the array. Here we
1925 see if any constraint on the index type of the base type
1926 can be used in the case of self-referential bound on
1927 the index type of the subtype. We look for a non-"infinite"
1928 and non-self-referential bound from any type involved and
1929 handle each bound separately. */
1954 gnu_this_max
1958 gnu_base_min)),
1959 size_zero_node);
1965 gnu_max_size
1979 }
1981 /* Then flatten: create the array of arrays. */
1985 /* One of the above calls might have caused us to be elaborated,
1986 so don't blow up if so. */
1988 {
1991 }
1993 /* Get and validate any specified Component_Size, but if Packed,
1994 ignore it since the front end will have taken care of it. */
1995 gnu_comp_size
1997 gnat_entity,
2002 /* If the component type is a RECORD_TYPE that has a self-referential
2003 size, use the maxium size. */
2009 {
2014 }
2028 {
2031 /* If the type below this an multi-array type, then this
2032 does not not have aliased components.
2034 ??? Otherwise, for now, we say that any component of aggregate
2035 type is addressable because the front end may take 'Reference
2036 of it. But we have to make it addressable if it must be passed
2037 by reference or it that is the default. */
2043 }
2045 /* If we are at file level and this is a multi-dimensional array, we
2046 need to make a variable corresponding to the stride of the
2047 inner dimensions. */
2049 {
2051 tree gnu_arr_type;
2057 {
2065 /* ??? For now, store the size as a multiple of the
2066 alignment of the element type in bytes so that we
2067 can see the alignment from the tree. */
2069 = build_binary_op
2071 elaborate_expression_1
2080 }
2081 }
2083 /* If we need to write out a record type giving the names of
2084 the bounds, do it now. */
2086 {
2089 tree gnu_field;
2095 {
2096 tree gnu_type_name
2103 integer_type_node,
2104 gnu_bound_rec_type,
2108 }
2112 }
2119 /* If our size depends on a placeholder and the maximum size doesn't
2120 overflow, use it. */
2127 {
2133 }
2135 /* Set our alias set to that of our base type. This gives all
2136 array subtypes the same alias set. */
2138 }
2140 /* If this is a packed type, make this type the same as the packed
2141 array type, but do some adjusting in the type first. */
2144 {
2145 Entity_Id gnat_index;
2146 tree gnu_inner_type;
2148 /* First finish the type we had been making so that we output
2149 debugging information for it */
2150 gnu_type
2153 | (TYPE_QUAL_VOLATILE
2161 /* Save it as our equivalent in case the call below elaborates
2162 this type again. */
2176 /* We need to point the type we just made to our index type so
2177 the actual bounds can be put into a template. */
2183 {
2185 {
2186 /* The TYPE_ACTUAL_BOUNDS field is also used for the modulus.
2187 If it is, we need to make another type. */
2189 {
2190 tree gnu_subtype;
2207 }
2210 }
2216 SET_TYPE_ACTUAL_BOUNDS
2223 SET_TYPE_ACTUAL_BOUNDS
2230 }
2231 }
2233 /* Abort if packed array with no packed array type field set. */
2234 else
2240 /* Create the type for a string literal. */
2241 {
2242 Entity_Id gnat_full_type
2247 tree gnu_string_array_type
2249 tree gnu_string_index_type
2252 tree gnu_lower_bound
2257 tree gnu_upper_bound
2259 gnu_lower_bound,
2261 tree gnu_range_type
2264 tree gnu_index_type
2269 gnu_range_type);
2271 gnu_type
2273 gnu_index_type);
2275 }
2278 /* Record Types and Subtypes
2280 The following fields are defined on record types:
2282 Has_Discriminants True if the record has discriminants
2283 First_Discriminant Points to head of list of discriminants
2284 First_Entity Points to head of list of fields
2285 Is_Tagged_Type True if the record is tagged
2287 Implementation of Ada records and discriminated records:
2289 A record type definition is transformed into the equivalent of a C
2290 struct definition. The fields that are the discriminants which are
2291 found in the Full_Type_Declaration node and the elements of the
2292 Component_List found in the Record_Type_Definition node. The
2293 Component_List can be a recursive structure since each Variant of
2294 the Variant_Part of the Component_List has a Component_List.
2296 Processing of a record type definition comprises starting the list of
2297 field declarations here from the discriminants and the calling the
2298 function components_to_record to add the rest of the fields from the
2299 component list and return the gnu type node. The function
2300 components_to_record will call itself recursively as it traverses
2301 the tree. */
2305 {
2306 gnu_type
2307 = build_complex_type
2308 (get_unpadded_type
2311 (Component_List
2312 (Type_Definition
2316 }
2318 {
2321 Entity_Id gnat_field;
2322 tree gnu_field;
2324 tree gnu_get_parent;
2331 bool is_extension
2335 /* See if all fields have a rep clause. Stop when we find one
2336 that doesn't. */
2345 /* If this is a record extension, go a level further to find the
2346 record definition. Also, verify we have a Parent_Subtype. */
2348 {
2355 }
2357 /* Make a node for the record. If we are not defining the record,
2358 suppress expanding incomplete types. We use the same RECORD_TYPE
2359 as for a dummy type and reset TYPE_DUMMY_P to show it's no longer
2360 a dummy.
2362 It is very tempting to delay resetting this bit until we are done
2363 with completing the type, e.g. to let possible intermediate
2364 elaboration of access types designating the record know it is not
2365 complete and arrange for update_pointer_to to fix things up later.
2367 It would be wrong, however, because dummy types are expected only
2368 to be created for Ada incomplete or private types, which is not
2369 what we have here. Doing so would make other parts of gigi think
2370 we are dealing with a really incomplete or private type, and have
2371 nasty side effects, typically on the generation of the associated
2372 debugging information. */
2385 /* If both a size and rep clause was specified, put the size in
2386 the record type now so that it can get the proper mode. */
2390 /* Always set the alignment here so that it can be used to
2391 set the mode, if it is making the alignment stricter. If
2392 it is invalid, it will be checked again below. If this is to
2393 be Atomic, choose a default alignment of a word unless we know
2394 the size and it's smaller. */
2403 /* If we have a Parent_Subtype, make a field for the parent. If
2404 this record has rep clauses, force the position to zero. */
2406 {
2407 tree gnu_parent;
2409 /* A major complexity here is that the parent subtype will
2410 reference our discriminants. But those must reference
2411 the parent component of this record. So here we will
2412 initialize each of those components to a COMPONENT_REF.
2413 The first operand of that COMPONENT_REF is another
2414 COMPONENT_REF which will be filled in below, once
2415 the parent type can be safely built. */
2420 NULL_TREE),
2421 NULL_TREE);
2428 save_gnu_tree
2432 gnu_get_parent,
2435 NULL_TREE),
2440 gnu_field_list
2450 }
2452 /* Add the fields for the discriminants into the record. */
2458 {
2459 /* If this is a record extension and this discriminant
2460 is the renaming of another discriminant, we've already
2461 handled the discriminant above. */
2466 gnu_field
2469 /* Make an expression using a PLACEHOLDER_EXPR from the
2470 FIELD_DECL node just created and link that with the
2471 corresponding GNAT defining identifier. Then add to the
2472 list of fields. */
2482 }
2484 /* Put the discriminants into the record (backwards), so we can
2485 know the appropriate discriminant to use for the names of the
2486 variants. */
2489 /* Add the listed fields into the record and finish up. */
2495 {
2497 defer_debug_level++;
2499 defer_debug_incomplete_list
2501 defer_debug_incomplete_list);
2502 }
2504 /* We used to remove the associations of the discriminants and
2505 _Parent for validity checking, but we may need them if there's
2506 Freeze_Node for a subtype used in this record. */
2511 /* If it is a tagged record force the type to BLKmode to insure
2512 that these objects will always be placed in memory. Do the
2513 same thing for limited record types. */
2517 /* If this is a derived type, we must make the alias set of this type
2518 the same as that of the type we are derived from. We assume here
2519 that the other type is already frozen. */
2525 /* Fill in locations of fields. */
2528 /* If there are any entities in the chain corresponding to
2529 components that we did not elaborate, ensure we elaborate their
2530 types if they are Itypes. */
2538 }
2542 /* If an equivalent type is present, that is what we should use.
2543 Otherwise, fall through to handle this like a record subtype
2544 since it may have constraints. */
2547 {
2552 }
2554 /* ... fall through ... */
2558 /* If Cloned_Subtype is Present it means this record subtype has
2559 identical layout to that type or subtype and we should use
2560 that GCC type for this one. The front end guarantees that
2561 the component list is shared. */
2563 {
2567 }
2569 /* Otherwise, first ensure the base type is elaborated. Then, if we are
2570 changing the type, make a new type with each field having the
2571 type of the field in the new subtype but having the position
2572 computed by transforming every discriminant reference according
2573 to the constraints. We don't see any difference between
2574 private and nonprivate type here since derivations from types should
2575 have been deferred until the completion of the private type. */
2576 else
2577 {
2579 tree gnu_base_type;
2580 tree gnu_orig_type;
2585 /* Get the base type initially for its alignment and sizes. But
2586 if it is a padded type, we do all the other work with the
2587 unpadded type. */
2596 {
2599 }
2601 /* When the type has discriminants, and these discriminants
2602 affect the shape of what it built, factor them in.
2604 If we are making a subtype of an Unchecked_Union (must be an
2605 Itype), just return the type.
2607 We can't just use Is_Constrained because private subtypes without
2608 discriminants of full types with discriminants with default
2609 expressions are Is_Constrained but aren't constrained! */
2617 {
2618 Entity_Id gnat_field;
2620 tree gnu_pos_list
2623 BIGGEST_ALIGNMENT);
2624 tree gnu_subst_list
2626 definition);
2627 tree gnu_temp;
2633 gnat_entity);
2645 {
2646 tree gnu_old_field
2649 tree gnu_offset
2651 gnu_pos_list));
2654 tree gnu_field_type
2658 unsigned int offset_align
2661 tree gnu_field;
2663 /* If there was a component clause, the field types must be
2664 the same for the type and subtype, so copy the data from
2665 the old field to avoid recomputation here. Also if the
2666 field is justified modular and the optimization in
2667 gnat_to_gnu_field was applied. */
2674 {
2677 }
2679 /* If this was a bitfield, get the size from the old field.
2680 Also ensure the type can be placed into a bitfield. */
2682 {
2688 }
2697 /* If the size is now a constant, we can set it as the
2698 size of the field when we make it. Otherwise, we need
2699 to deal with it specially. */
2703 gnu_field
2704 = create_field_decl
2710 {
2719 bitsize_unit_node));
2721 }
2725 SET_DECL_ORIGINAL_FIELD
2736 }
2738 /* Now go through the entities again looking for Itypes that
2739 we have not elaborated but should (e.g., Etypes of fields
2740 that have Original_Components). */
2751 /* Now set the size, alignment and alias set of the new type to
2752 match that of the old one, doing any substitutions, as
2753 above. */
2779 SET_TYPE_ADA_SIZE
2784 /* Recompute the mode of this record type now that we know its
2785 actual size. */
2788 /* Fill in locations of fields. */
2790 }
2792 /* If we've made a new type, record it and make an XVS type to show
2793 what this is a subtype of. Some debuggers require the XVS
2794 type to be output first, so do it in that order. */
2796 {
2798 {
2809 integer_type_node,
2810 gnu_subtype_marker,
2814 }
2821 }
2823 /* Otherwise, go down all the components in the new type and
2824 make them equivalent to those in the base type. */
2825 else
2832 gnat_to_gnu_field_decl
2834 }
2839 /* If we are not defining this entity, and we have incomplete
2840 entities being processed above us, make a dummy type and
2841 fill it in later. */
2843 {
2847 gnu_type
2848 = build_pointer_type
2861 }
2863 /* ... fall through ... */
2870 {
2872 Entity_Id gnat_desig_full
2874 Incomplete_Or_Private_Kind))
2876 /* We want to know if we'll be seeing the freeze node for any
2877 incomplete type we may be pointing to. */
2878 bool in_main_unit
2894 {
2896 {
2900 }
2902 Incomplete_Or_Private_Kind))
2904 }
2909 /* If either the designated type or its full view is an
2910 unconstrained array subtype, replace it with the type it's a
2911 subtype of. This avoids problems with multiple copies of
2912 unconstrained array types. */
2921 /* If the designated type is a subtype of an incomplete record type,
2922 use the parent type to avoid order of elaboration issues. This
2923 can lose some code efficiency, but there is no alternative. */
2929 /* If we are pointing to an incomplete type whose completion is an
2930 unconstrained array, make a fat pointer type instead of a pointer
2931 to VOID. The two types in our fields will be pointers to VOID and
2932 will be replaced in update_pointer_to. Similarly, if the type
2933 itself is a dummy type or an unconstrained array. Also make
2934 a dummy TYPE_OBJECT_RECORD_TYPE in case we have any thin
2935 pointers to it. */
2951 && defer_incomplete_level
2955 {
2956 tree gnu_old
2960 tree fields;
2962 /* Show the dummy we get will be a fat pointer. */
2965 /* If the call above got something that has a pointer, that
2966 pointer is our type. This could have happened either
2967 because the type was elaborated or because somebody
2968 else executed the code below. */
2971 {
2977 fields
2979 create_field_decl
2984 ptr_void_type_node,
2987 /* Make sure we can place this into a register. */
2998 }
2999 }
3001 /* If we already know what the full type is, use it. */
3006 /* Get the type of the thing we are to point to and build a pointer
3007 to it. If it is a reference to an incomplete or private type with a
3008 full view that is a record, make a dummy type node and get the
3009 actual type later when we have verified it is safe. */
3015 {
3018 }
3020 /* Likewise if we are pointing to a record or array and we are to defer
3021 elaborating incomplete types. We do this since this access type
3022 may be the full view of some private type. Note that the
3023 unconstrained array case is handled above. */
3031 {
3034 }
3036 {
3037 gnu_type
3039 p_mode,
3042 }
3043 else
3046 /* It is possible that the above call to gnat_to_gnu_type resolved our
3047 type. If so, just return it. */
3049 {
3052 }
3054 /* If we have a GCC type for the designated type, possibly modify it
3055 if we are pointing only to constant objects and then make a pointer
3056 to it. Don't do this for unconstrained arrays. */
3058 {
3061 {
3062 gnu_desig_type
3063 = build_qualified_type
3067 /* Some extra processing is required if we are building a
3068 pointer to an incomplete type (in the GCC sense). We might
3069 have such a type if we just made a dummy, or directly out
3070 of the call to gnat_to_gnu_type above if we are processing
3071 an access type for a record component designating the
3072 record type itself. */
3074 {
3075 /* We must ensure that the pointer to variant we make will
3076 be processed by update_pointer_to when the initial type
3077 is completed. Pretend we made a dummy and let further
3078 processing act as usual. */
3081 /* We must ensure that update_pointer_to will not retrieve
3082 the dummy variant when building a properly qualified
3083 version of the complete type. We take advantage of the
3084 fact that get_qualified_type is requiring TYPE_NAMEs to
3085 match to influence build_qualified_type and then also
3086 update_pointer_to here. */
3089 }
3090 }
3092 gnu_type
3095 }
3097 /* If we are not defining this object and we made a dummy pointer,
3098 save our current definition, evaluate the actual type, and replace
3099 the tentative type we made with the actual one. If we are to defer
3100 actually looking up the actual type, make an entry in the
3101 deferred list. */
3104 {
3105 tree gnu_old_type
3111 gnu_type
3112 = build_pointer_type
3113 (TYPE_OBJECT_RECORD_TYPE
3123 /* Note that the call to gnat_to_gnu_type here might have
3124 updated gnu_old_type directly, in which case it is not a
3125 dummy type any more when we get into update_pointer_to.
3127 This may happen for instance when the designated type is a
3128 record type, because their elaboration starts with an
3129 initial node from make_dummy_type, which may yield the same
3130 node as the one we got.
3132 Besides, variants of this non-dummy type might have been
3133 created along the way. update_pointer_to is expected to
3134 properly take care of those situations. */
3137 else
3138 {
3146 }
3147 }
3148 }
3155 else
3156 /* The runtime representation is the equivalent type. */
3170 /* We treat this as identical to its base type; any constraint is
3171 meaningful only to the front end.
3173 The designated type must be elaborated as well, if it does
3174 not have its own freeze node. Designated (sub)types created
3175 for constrained components of records with discriminants are
3176 not frozen by the front end and thus not elaborated by gigi,
3177 because their use may appear before the base type is frozen,
3178 and because it is not clear that they are needed anywhere in
3179 Gigi. With the current model, there is no correct place where
3180 they could be elaborated. */
3187 {
3188 /* If we are not defining this entity, and we have incomplete
3189 entities being processed above us, make a dummy type and
3190 elaborate it later. */
3192 {
3195 tree gnu_ptr_type
3196 = build_pointer_type
3203 }
3206 Incomplete_Or_Private_Kind))
3207 ;
3208 else
3211 }
3216 /* Subprogram Entities
3218 The following access functions are defined for subprograms (functions
3219 or procedures):
3221 First_Formal The first formal parameter.
3222 Is_Imported Indicates that the subprogram has appeared in
3223 an INTERFACE or IMPORT pragma. For now we
3224 assume that the external language is C.
3225 Is_Inlined True if the subprogram is to be inlined.
3227 In addition for function subprograms we have:
3229 Etype Return type of the function.
3231 Each parameter is first checked by calling must_pass_by_ref on its
3232 type to determine if it is passed by reference. For parameters which
3233 are copied in, if they are Ada IN OUT or OUT parameters, their return
3234 value becomes part of a record which becomes the return type of the
3235 function (C function - note that this applies only to Ada procedures
3236 so there is no Ada return type). Additional code to store back the
3237 parameters will be generated on the caller side. This transformation
3238 is done here, not in the front-end.
3240 The intended result of the transformation can be seen from the
3241 equivalent source rewritings that follow:
3243 struct temp {int a,b};
3244 procedure P (A,B: IN OUT ...) is temp P (int A,B) {
3245 .. ..
3246 end P; return {A,B};
3247 }
3248 procedure call
3250 {
3251 temp t;
3252 P(X,Y); t = P(X,Y);
3253 X = t.a , Y = t.b;
3254 }
3256 For subprogram types we need to perform mainly the same conversions to
3257 GCC form that are needed for procedures and function declarations. The
3258 only difference is that at the end, we make a type declaration instead
3259 of a function declaration. */
3264 {
3265 /* The first GCC parameter declaration (a PARM_DECL node). The
3266 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3267 actually is the head of this parameter list. */
3269 /* The type returned by a function. If the subprogram is a procedure
3270 this type should be void_type_node. */
3272 /* List of fields in return type of procedure with copy in copy out
3273 parameters. */
3275 /* Non-null for subprograms containing parameters passed by copy in
3276 copy out (Ada IN OUT or OUT parameters not passed by reference),
3277 in which case it is the list of nodes used to specify the values of
3278 the in out/out parameters that are returned as a record upon
3279 procedure return. The TREE_PURPOSE of an element of this list is
3280 a field of the record and the TREE_VALUE is the PARM_DECL
3281 corresponding to that field. This list will be saved in the
3282 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3284 /* If an import pragma asks to map this subprogram to a GCC builtin,
3285 this is the builtin DECL node. */
3287 Entity_Id gnat_param;
3290 bool extern_flag
3302 /* A parameter may refer to this type, so defer completion
3303 of any incomplete types. */
3306 /* If the subprogram has an alias, it is probably inherited, so
3307 we can use the original one. If the original "subprogram"
3308 is actually an enumeration literal, it may be the first use
3309 of its type, so we must elaborate that type now. */
3311 {
3318 /* Elaborate any Itypes in the parameters of this entity. */
3326 }
3328 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3329 corresponding DECL node.
3331 We still want the parameter associations to take place because the
3332 proper generation of calls depends on it (a GNAT parameter without
3333 a corresponding GCC tree has a very specific meaning), so we don't
3334 just break here. */
3338 /* ??? What if we don't find the builtin node above ? warn ? err ?
3339 In the current state we neither warn nor err, and calls will just
3340 be handled as for regular subprograms. */
3345 /* If this function returns by reference, make the actual
3346 return type of this function the pointer and mark the decl. */
3348 {
3351 }
3353 /* If the Mechanism is By_Reference, ensure the return type uses
3354 the machine's by-reference mechanism, which may not the same
3355 as above (e.g., it might be by passing a fake parameter). */
3358 {
3361 }
3363 /* If we are supposed to return an unconstrained array,
3364 actually return a fat pointer and make a note of that. Return
3365 a pointer to an unconstrained record of variable size. */
3367 {
3370 }
3372 /* If the type requires a transient scope, the result is allocated
3373 on the secondary stack, so the result type of the function is
3374 just a pointer. */
3376 {
3379 }
3381 /* If the type is a padded type and the underlying type would not
3382 be passed by reference or this function has a foreign convention,
3383 return the underlying type. */
3391 /* If the return type is unconstrained, that means it must have a
3392 maximum size. We convert the function into a procedure and its
3393 caller will pass a pointer to an object of that maximum size as the
3394 first parameter when we call the function. */
3396 {
3398 gnu_param_list
3403 }
3405 /* If the return type has a size that overflows, we cannot have
3406 a function that returns that type. This usage doesn't make
3407 sense anyway, so give an error here. */
3410 {
3412 gnat_entity);
3418 }
3420 /* Look at all our parameters and get the type of
3421 each. While doing this, build a copy-out structure if
3422 we need one. */
3427 {
3437 /* Builtins are expanded inline and there is no real call sequence
3438 involved. so the type expected by the underlying expander is
3439 always the type of each argument "as is". */
3443 /* Otherwise, see if a Mechanism was supplied that forced this
3444 parameter to be passed one way or another. */
3448 ;
3456 {
3462 else
3464 }
3465 else
3468 /* If this is either a foreign function or if the
3469 underlying type won't be passed by reference, strip off
3470 possible padding type. */
3476 && (req_by_copy
3478 (TYPE_FIELDS
3482 /* If this is an IN parameter it is read-only, so make a variant
3483 of the type that is read-only.
3485 ??? However, if this is an unconstrained array, that type can
3486 be very complex. So skip it for now. Likewise for any other
3487 self-referential type. */
3491 gnu_param_type
3496 /* For foreign conventions, pass arrays as a pointer to the
3497 underlying type. First check for unconstrained array and get
3498 the underlying array. Then get the component type and build
3499 a pointer to it. */
3502 gnu_param_type
3507 gnu_param_type
3508 = build_pointer_type
3513 && !req_by_copy
3515 {
3516 /* Strip off any multi-dimensional entries, then strip
3517 off the last array to get the component type. */
3526 gnu_param_type
3532 }
3534 /* Fat pointers are passed as thin pointers for foreign
3535 conventions. */
3538 gnu_param_type
3542 /* If we must pass or were requested to pass by reference, do so.
3543 If we were requested to pass by copy, do so.
3544 Otherwise, for foreign conventions, pass all in out parameters
3545 or aggregates by reference. For COBOL and Fortran, pass
3546 all integer and FP types that way too. For Convention Ada,
3547 use the standard Ada default. */
3549 || (!req_by_copy
3559 /* For convention Ada, see if we pass by reference
3560 by default. */
3563 {
3566 }
3574 /* If this is an OUT parameter that isn't passed by reference
3575 and isn't a pointer or aggregate, we don't make a PARM_DECL
3576 for it. Instead, it will be a VAR_DECL created when we process
3577 the procedure. For the special parameter of Valued_Procedure,
3578 never pass it in.
3580 An exception is made to cover the RM-6.4.1 rule requiring "by
3581 copy" out parameters with discriminants or implicit initial
3582 values to be handled like in out parameters. These type are
3583 normally built as aggregates, and hence passed by reference,
3584 except for some packed arrays which end up encoded in special
3585 integer types.
3587 The exception we need to make is then for packed arrays of
3588 records with discriminants or implicit initial values. We have
3589 no light/easy way to check for the latter case, so we merely
3590 check for packed arrays of records. This may lead to useless
3591 copy-in operations, but in very rare cases only, as these would
3592 be exceptions in a set of already exceptional situations. */
3595 || (!by_descr_p
3603 else
3604 {
3605 gnu_param
3606 = create_param_decl
3608 by_ref_p || by_component_ptr_p
3622 /* If a parameter is a pointer, this function may modify
3623 memory through it and thus shouldn't be considered
3624 a pure function. Also, the memory may be modified
3625 between two calls, so they can't be CSE'ed. The latter
3626 case also handles by-ref parameters. */
3630 }
3633 {
3635 {
3640 }
3649 gnu_return_list);
3650 }
3651 }
3653 /* Do not compute record for out parameters if subprogram is
3654 stubbed since structures are incomplete for the back-end. */
3657 {
3658 /* If all types are not complete, defer emission of debug
3659 information for this record types. Otherwise, we risk emitting
3660 debug information for a dummy type contained in the fields
3661 for that record. */
3666 {
3668 defer_debug_level++;
3670 defer_debug_incomplete_list
3672 defer_debug_incomplete_list);
3673 }
3674 }
3676 /* If we have a CICO list but it has only one entry, we convert
3677 this function into a function that simply returns that one
3678 object. */
3683 {
3693 }
3695 /* Both lists ware built in reverse. */
3699 gnu_type
3702 returns_by_ref,
3704 returns_by_target_ptr);
3706 /* A subprogram (something that doesn't return anything) shouldn't
3707 be considered Pure since there would be no reason for such a
3708 subprogram. Note that procedures with Out (or In Out) parameters
3709 have already been converted into a function with a return type. */
3713 gnu_type
3721 /* If we have a builtin decl for that function, check the signatures
3722 compatibilities. If the signatures are compatible, use the builtin
3723 decl. If they are not, we expect the checker predicate to have
3724 posted the appropriate errors, and just continue with what we have
3725 so far. */
3727 {
3731 {
3735 }
3736 }
3738 /* If there was no specified Interface_Name and the external and
3739 internal names of the subprogram are the same, only use the
3740 internal name to allow disambiguation of nested subprograms. */
3744 /* If we are defining the subprogram and it has an Address clause
3745 we must get the address expression from the saved GCC tree for the
3746 subprogram if it has a Freeze_Node. Otherwise, we elaborate
3747 the address expression here since the front-end has guaranteed
3748 in that case that the elaboration has no effects. If there is
3749 an Address clause and we are not defining the object, just
3750 make it a constant. */
3752 {
3756 gnu_address
3767 gnu_decl
3772 }
3778 gnat_entity);
3779 else
3780 {
3785 gnat_entity);
3788 }
3789 }
3800 /* If this type does not have a full view in the unit we are
3801 compiling, then just get the type from its Etype. */
3803 {
3804 /* If this is an incomplete type with no full view, it must be
3805 either a limited view brought in by a limited_with clause, in
3806 which case we use the non-limited view, or a Taft Amendement
3807 type, in which case we just return a dummy type. */
3809 {
3814 else
3816 }
3821 else
3822 {
3826 }
3829 }
3831 /* Otherwise, if we are not defining the type now, get the
3832 type from the full view. But always get the type from the full
3833 view for define on use types, since otherwise we won't see them! */
3840 {
3845 }
3847 /* For incomplete types, make a dummy type entry which will be
3848 replaced later. */
3851 /* Save this type as the full declaration's type so we can do any needed
3852 updates when we see it. */
3859 /* Simple class_wide types are always viewed as their root_type
3860 by Gigi unless an Equivalent_Type is specified. */
3864 else
3876 else
3888 /* Nothing at all to do here, so just return an ERROR_MARK and claim
3889 we've already saved it, so we don't try to. */
3896 }
3898 /* If we had a case where we evaluated another type and it might have
3899 defined this one, handle it here. */
3901 {
3904 }
3906 /* If we are processing a type and there is either no decl for it or
3907 we just made one, do some common processing for the type, such as
3908 handling alignment and possible padding. */
3911 {
3919 /* ??? Don't set the size for a String_Literal since it is either
3920 confirming or we don't handle it properly (if the low bound is
3921 non-constant). */
3927 /* If a size was specified, see if we can make a new type of that size
3928 by rearranging the type, for example from a fat to a thin pointer. */
3930 {
3931 gnu_type
3938 }
3940 /* If the alignment hasn't already been processed and this is
3941 not an unconstrained array, see if an alignment is specified.
3942 If not, we pick a default alignment for atomic objects. */
3944 ;
3958 /* See if we need to pad the type. If we did, and made a record,
3959 the name of the new type may be changed. So get it back for
3960 us when we make the new TYPE_DECL below. */
3965 {
3969 }
3973 /* If we are at global level, GCC will have applied variable_size to
3974 the type, but that won't have done anything. So, if it's not
3975 a constant or self-referential, call elaborate_expression_1 to
3976 make a variable for the size rather than calculating it each time.
3977 Handle both the RM size and the actual size. */
3982 {
3986 {
3993 }
3994 else
3995 {
4002 /* ??? For now, store the size as a multiple of the alignment
4003 in bytes so that we can see the alignment from the tree. */
4005 = build_binary_op
4007 elaborate_expression_1
4018 SET_TYPE_ADA_SIZE
4021 gnat_entity,
4025 }
4026 }
4028 /* If this is a record type or subtype, call elaborate_expression_1 on
4029 any field position. Do this for both global and local types.
4030 Skip any fields that we haven't made trees for to avoid problems with
4031 class wide types. */
4036 {
4039 /* ??? Unfortunately, GCC needs to be able to prove the
4040 alignment of this offset and if it's a variable, it can't.
4041 In GCC 3.4, we'll use DECL_OFFSET_ALIGN in some way, but
4042 right now, we have to put in an explicit multiply and
4043 divide by that value. */
4046 = build_binary_op
4048 elaborate_expression_1
4057 }
4061 | (TYPE_QUAL_VOLATILE
4074 else
4076 }
4079 {
4082 /* Back-annotate the Alignment of the type if not already in the
4083 tree. Likewise for sizes. */
4089 {
4090 /* If the size is self-referential, we annotate the maximum
4091 value of that size. */
4100 {
4101 /* In this mode the tag and the parent components are not
4102 generated by the front-end, so the sizes must be adjusted
4103 explicitly now. */
4109 {
4110 size_offset
4114 }
4115 else
4123 }
4124 }
4128 }
4138 /* If we haven't already, associate the ..._DECL node that we just made with
4139 the input GNAT entity node. */
4143 /* If this is an enumeral or floating-point type, we were not able to set
4144 the bounds since they refer to the type. These bounds are always static.
4146 For enumeration types, also write debugging information and declare the
4147 enumeration literal table, if needed. */
4151 {
4154 /* If this is a padded type, we need to use the underlying type. */
4159 /* If this is a floating point type and we haven't set a floating
4160 point type yet, use this in the evaluation of the bounds. */
4170 {
4173 /* Since this has both a typedef and a tag, avoid outputting
4174 the name twice. */
4177 }
4178 }
4180 /* If we deferred processing of incomplete types, re-enable it. If there
4181 were no other disables and we have some to process, do so. */
4183 {
4189 {
4196 }
4197 }
4199 /* If we are not defining this type, see if it's in the incomplete list.
4200 If so, handle that list entry now. */
4202 {
4207 {
4211 }
4212 }
4214 /* If there are no incomplete types and we have deferred emission
4215 of debug information, check whether we have finished defining
4216 all nested records.
4217 If so, handle the list now. */
4220 defer_debug_level--;
4223 && !defer_incomplete_level
4225 {
4231 {
4234 }
4237 }
4240 force_global--;
4249 }
4251 /* Similar, but if the returned value is a COMPONENT_REF, return the
4252 FIELD_DECL. */
4254 tree
4256 {
4263 }
4264 \f
4265 /* Given GNAT_ENTITY, elaborate all expressions that are required to
4266 be elaborated at the point of its definition, but do nothing else. */
4268 void
4270 {
4272 {
4279 {
4283 /* ??? Tests for avoiding static constraint error expression
4284 is needed until the front stops generating bogus conversions
4285 on bounds of real types. */
4294 }
4297 {
4301 /* If this is a record extension, go a level further to find the
4302 record definition. */
4305 }
4315 {
4316 Node_Id gnat_discriminant_expr;
4317 Entity_Id gnat_field;
4320 gnat_discriminant_expr
4325 /* ??? For now, ignore access discriminants. */
4328 gnat_entity,
4330 }
4333 }
4334 }
4335 \f
4336 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
4337 any entities on its entity chain similarly. */
4339 void
4341 {
4342 Entity_Id gnat_sub_entity;
4345 /* If this has an entity list, process all in the list. */
4362 /* Now clear this if it has been defined, but only do so if it isn't
4363 a subprogram or parameter. We could refine this, but it isn't
4364 worth it. If this is statically allocated, it is supposed to
4365 hang around out of cope. */
4368 {
4371 }
4372 }
4373 \f
4374 /* Set the alias set of GNU_NEW_TYPE to be that of GNU_OLD_TYPE. If this
4375 is a multi-dimensional array type, do this recursively. */
4377 static void
4379 {
4380 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
4381 of a one-dimensional array, since the padding has the same alias set
4382 as the field type, but if it's a multi-dimensional array, we need to
4383 see the inner types. */
4389 /* We need to be careful here in case GNU_OLD_TYPE is an unconstrained
4390 array. In that case, it doesn't have the same shape as GNU_NEW_TYPE,
4391 so we need to go down to what does. */
4393 gnu_old_type
4403 }
4404 \f
4405 /* Return a TREE_LIST describing the substitutions needed to reflect
4406 discriminant substitutions from GNAT_SUBTYPE to GNAT_TYPE and add
4407 them to GNU_LIST. If GNAT_TYPE is not specified, use the base type
4408 of GNAT_SUBTYPE. The substitutions can be in any order. TREE_PURPOSE
4409 gives the tree for the discriminant and TREE_VALUES is the replacement
4410 value. They are in the form of operands to substitute_in_expr.
4411 DEFINITION is as in gnat_to_gnu_entity. */
4413 static tree
4416 {
4417 Entity_Id gnat_discrim;
4418 Node_Id gnat_value;
4429 /* Ignore access discriminants. */
4432 elaborate_expression
4436 gnu_list);
4439 }
4440 \f
4441 /* For the following two functions: for each GNAT entity, the GCC
4442 tree node used as a dummy for that entity, if any. */
4446 /* Initialize the above table. */
4448 void
4450 {
4451 Node_Id gnat_node;
4459 }
4461 /* Make a dummy type corresponding to GNAT_TYPE. */
4463 tree
4465 {
4466 Entity_Id gnat_underlying;
4467 tree gnu_type;
4469 /* Find a full type for GNAT_TYPE, taking into account any class wide
4470 types. */
4480 ;
4482 /* If it there already a dummy type, use that one. Else make one. */
4486 /* If this is a record, make this a RECORD_TYPE or UNION_TYPE; else make
4487 it a VOID_TYPE. */
4489 {
4492 }
4495 else
4506 }
4507 \f
4508 /* Return true if the size represented by GNU_SIZE can be handled by an
4509 allocation. If STATIC_P is true, consider only what can be done with a
4510 static allocation. */
4512 static bool
4514 {
4515 HOST_WIDE_INT our_size;
4517 /* If this is not a static allocation, the only case we want to forbid
4518 is an overflowing size. That will be converted into a raise a
4519 Storage_Error. */
4524 /* Otherwise, we need to deal with both variable sizes and constant
4525 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
4526 since assemblers may not like very large sizes. */
4532 }
4533 \f
4534 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
4536 static void
4538 {
4539 Node_Id gnat_temp;
4544 {
4554 {
4556 (gnat_to_gnu
4563 (gnat_to_gnu
4564 (Expression
4567 }
4570 {
4597 }
4604 /* If we have an argument specified together with an attribute name,
4605 make it a single TREE_VALUE entry in a list of arguments, as GCC
4606 expects it. */
4609 else
4612 attr->error_point
4616 }
4617 }
4618 \f
4619 /* Get the unpadded version of a GNAT type. */
4621 tree
4623 {
4630 }
4631 \f
4632 /* Called when we need to protect a variable object using a save_expr. */
4634 tree
4636 {
4643 {
4651 }
4652 else
4654 }
4655 \f
4656 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
4657 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
4658 return the GCC tree to use for that expression. GNU_NAME is the
4659 qualification to use if an external name is appropriate and DEFINITION is
4660 nonzero if this is a definition of GNAT_ENTITY. If NEED_VALUE is nonzero,
4661 we need a result. Otherwise, we are just elaborating this for
4662 side-effects. If NEED_DEBUG is nonzero we need the symbol for debugging
4663 purposes even if it isn't needed for code generation. */
4665 static tree
4669 {
4670 tree gnu_expr;
4672 /* If we already elaborated this expression (e.g., it was involved
4673 in the definition of a private type), use the old value. */
4677 /* If we don't need a value and this is static or a discriment, we
4678 don't need to do anything. */
4685 /* Otherwise, convert this tree to its GCC equivalent. */
4686 gnu_expr
4690 /* Save the expression in case we try to elaborate this entity again. Since
4691 this is not a DECL, don't check it. Don't save if it's a discriminant. */
4696 }
4698 /* Similar, but take a GNU expression. */
4700 static tree
4704 {
4706 /* Strip any conversions to see if the expression is a readonly variable.
4707 ??? This really should remain readonly, but we have to think about
4708 the typing of the tree here. */
4713 /* In most cases, we won't see a naked FIELD_DECL here because a
4714 discriminant reference will have been replaced with a COMPONENT_REF
4715 when the type is being elaborated. However, there are some cases
4716 involving child types where we will. So convert it to a COMPONENT_REF
4717 here. We have to hope it will be at the highest level of the
4718 expression in these cases. */
4724 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
4725 that is a constant, make a variable that is initialized to contain the
4726 bound when the package containing the definition is elaborated. If
4727 this entity is defined at top level and a bound or discriminant value
4728 isn't a constant or a reference to a discriminant, replace the bound
4729 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
4730 rely here on the fact that an expression cannot contain both the
4731 discriminant and some other variable. */
4738 /* If this is a static expression or contains a discriminant, we don't
4739 need the variable for debugging (and can't elaborate anyway if a
4740 discriminant). */
4746 /* Now create the variable if we need it. */
4748 gnu_decl
4755 /* We only need to use this variable if we are in global context since GCC
4756 can do the right thing in the local case. */
4761 else
4763 }
4764 \f
4765 /* Create a record type that contains a field of TYPE with a starting bit
4766 position so that it is aligned to ALIGN bits and is SIZE bytes long. */
4768 tree
4770 {
4775 place));
4784 /* The bit position is obtained by "and"ing the alignment minus 1
4785 with the two's complement of the address and multiplying
4786 by the number of bits per unit. Do all this in sizetype. */
4791 size_addr_place),
4794 bitsize_unit_node);
4796 /* Create the field, with -1 as the 'addressable' indication to avoid the
4797 creation of a bitfield. We don't need one, it would have damaging
4798 consequences on the alignment computation, and create_field_decl would
4799 make one without this special argument, for instance because of the
4800 complex position expression. */
4809 bitsize_unit_node),
4815 }
4816 \f
4817 /* TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE, with BLKmode that's
4818 being used as the field type of a packed record. See if we can rewrite it
4819 as a record that has a non-BLKmode type, which we can pack tighter. If so,
4820 return the new type. If not, return the original type. */
4822 static tree
4824 {
4827 tree old_field;
4829 /* Copy the name and flags from the old type to that of the new and set
4830 the alignment to try for an integral type. For QUAL_UNION_TYPE,
4831 also copy the size. */
4840 {
4843 }
4849 /* Now copy the fields, keeping the position and size. */
4852 {
4854 tree new_field;
4870 SET_DECL_ORIGINAL_FIELD
4879 }
4884 }
4885 \f
4886 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
4887 if needed. We have already verified that SIZE and TYPE are large enough.
4889 GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
4890 to issue a warning.
4892 IS_USER_TYPE is true if we must be sure we complete the original type.
4894 DEFINITION is true if this type is being defined.
4896 SAME_RM_SIZE is true if the RM_Size of the resulting type is to be
4897 set to its TYPE_SIZE; otherwise, it's set to the RM_Size of the original
4898 type. */
4900 tree
4904 {
4906 tree record;
4907 tree field;
4909 /* If TYPE is a padded type, see if it agrees with any size and alignment
4910 we were given. If so, return the original type. Otherwise, strip
4911 off the padding, since we will either be returning the inner type
4912 or repadding it. If no size or alignment is specified, use that of
4913 the original padded type. */
4916 {
4933 }
4935 /* If the size is either not being changed or is being made smaller (which
4936 is not done here (and is only valid for bitfields anyway), show the size
4937 isn't changing. Likewise, clear the alignment if it isn't being
4938 changed. Then return if we aren't doing anything. */
4952 /* We used to modify the record in place in some cases, but that could
4953 generate incorrect debugging information. So make a new record
4954 type and name. */
4960 /* If we were making a type, complete the original type and give it a
4961 name. */
4968 gnat_entity);
4970 /* If we are changing the alignment and the input type is a record with
4971 BLKmode and a small constant size, try to make a form that has an
4972 integral mode. That might allow this record to have an integral mode,
4973 which will be much more efficient. There is no point in doing this if a
4974 size is specified unless it is also smaller than the biggest alignment
4975 and it is incorrect to do this if the size of the original type is not a
4976 multiple of the alignment. */
4982 && (!size
5004 /* Keep the RM_Size of the padded record as that of the old record
5005 if requested. */
5008 /* Unless debugging information isn't being written for the input type,
5009 write a record that shows what we are a subtype of and also make a
5010 variable that indicates our size, if variable. */
5014 {
5035 }
5042 /* If the size was widened explicitly, maybe give a warning. */
5048 {
5061 /* Generate message only for entities that come from source, since
5062 if we have an entity created by expansion, the message will be
5063 generated for some other corresponding source entity. */
5066 gnat_entity,
5073 }
5076 }
5077 \f
5078 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
5079 the value passed against the list of choices. */
5081 tree
5083 {
5084 Node_Id choice;
5085 Node_Id gnat_temp;
5090 {
5092 {
5097 /* There's no good type to use here, so we might as well use
5098 integer_type_node. */
5099 this_test
5113 this_test
5123 /* This represents either a subtype range, an enumeration
5124 literal, or a constant Ekind says which. If an enumeration
5125 literal or constant, fall through to the next case. */
5128 {
5134 this_test
5141 }
5142 /* ... fall through ... */
5147 single);
5156 }
5160 }
5163 }
5164 \f
5165 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
5166 placed in GNU_RECORD_TYPE.
5168 PACKED is 1 if the enclosing record is packed and -1 if the enclosing
5169 record has a Component_Alignment of Storage_Unit.
5171 DEFINITION is true if this field is for a record being defined. */
5173 static tree
5176 {
5181 tree gnu_field;
5182 bool needs_strict_alignment
5186 /* If this field requires strict alignment or contains an item of
5187 variable sized, pretend it isn't packed. */
5191 /* For packed records, this is one of the few occasions on which we use
5192 the official RM size for discrete or fixed-point components, instead
5193 of the normal GNAT size stored in Esize. See description in Einfo:
5194 "Handling of Type'Size Values" for further details. */
5204 /* If we are packing this record, have a specified size that's smaller than
5205 that of the field type, or a position is specified, and the field type is
5206 also a record that's BLKmode and with a small constant size, see if we
5207 can get a better form of the type that allows more packing. If we can,
5208 show a size was specified for it if there wasn't one so we know to make
5209 this a bitfield and avoid making things wider. */
5215 || (gnu_size
5218 {
5219 /* See what the alternate type and size would be. */
5222 /* Compute whether we should avoid the substitution. */
5224 /* There is no point substituting if there is no change. */
5226 ||
5227 /* The size of an aliased field must be an exact multiple of the
5228 type's alignment, which the substitution might increase. Reject
5229 substitutions that would so invalidate a component clause when the
5230 specified position is byte aligned, as the change would have no
5231 real benefit from the packing standpoint anyway. */
5236 );
5238 /* Substitute unless told otherwise. */
5240 {
5245 }
5246 }
5248 /* If we are packing the record and the field is BLKmode, round the
5249 size up to a byte boundary. */
5254 {
5259 /* Ensure the position does not overlap with the parent subtype,
5260 if there is one. */
5262 {
5263 tree gnu_parent
5269 {
5270 post_error_ne_tree
5274 }
5275 }
5277 /* If this field needs strict alignment, ensure the record is
5278 sufficiently aligned and that that position and size are
5279 consistent with the alignment. */
5281 {
5288 /* If Atomic, the size must match exactly that of the field. */
5291 {
5292 post_error_ne_tree
5298 }
5300 /* If Aliased, the size must match exactly the rounded size. We
5301 used to be more accommodating here and accept greater sizes, but
5302 fully supporting this case on big-endian platforms would require
5303 switching to a more involved layout for the field. */
5305 && gnu_size
5307 {
5308 post_error_ne_tree
5311 gnu_rounded_size);
5313 }
5318 {
5320 post_error_ne_num
5326 post_error_ne_num
5332 post_error_ne_num
5336 else
5340 }
5341 }
5345 }
5347 /* If the record has rep clauses and this is the tag field, make a rep
5348 clause for it as well. */
5351 {
5354 }
5356 /* We need to make the size the maximum for the type if it is
5357 self-referential and an unconstrained type. In that case, we can't
5358 pack the field since we can't make a copy to align it. */
5360 && !gnu_size
5363 {
5366 }
5368 /* If no size is specified (or if there was an error), don't specify a
5369 position. */
5372 else
5373 {
5374 /* If the field's type is justified modular, we would need to remove
5375 the wrapper to (better) meet the layout requirements. However we
5376 can do so only if the field is not aliased to preserve the unique
5377 layout and if the prescribed size is not greater than that of the
5378 packed array to preserve the justification. */
5386 gnu_field_type
5391 }
5396 /* Now create the decl for the field. */
5408 }
5409 \f
5410 /* Return true if TYPE is a type with variable size, a padding type with a
5411 field of variable size or is a record that has a field such a field. */
5413 static bool
5415 {
5416 tree field;
5418 /* We need not be concerned about this at all if we don't have
5419 strict alignment. */
5437 }
5438 \f
5439 /* Return a GCC tree for a record type given a GNAT Component_List and a chain
5440 of GCC trees for fields that are in the record and have already been
5441 processed. When called from gnat_to_gnu_entity during the processing of a
5442 record type definition, the GCC nodes for the discriminants will be on
5443 the chain. The other calls to this function are recursive calls from
5444 itself for the Component_List of a variant and the chain is empty.
5446 PACKED is 1 if this is for a record with "pragma pack" and -1 is this is
5447 for a record type with "pragma component_alignment (storage_unit)".
5449 DEFINITION is true if we are defining this record.
5451 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
5452 with a rep clause is to be added. If it is nonzero, that is all that
5453 should be done with such fields.
5455 CANCEL_ALIGNMENT, if true, means the alignment should be zeroed before
5456 laying out the record. This means the alignment only serves to force fields
5457 to be bitfields, but not require the record to be that aligned. This is
5458 used for variants.
5460 ALL_REP, if true, means a rep clause was found for all the fields. This
5461 simplifies the logic since we know we're not in the mixed case.
5463 DEFER_DEBUG, if true, means that the debugging routines should not be
5464 called when finishing constructing the record type.
5466 The processing of the component list fills in the chain with all of the
5467 fields of the record and then the record type is finished. */
5469 static void
5474 {
5475 Node_Id component_decl;
5476 Entity_Id gnat_field;
5477 Node_Id variant_part;
5478 Node_Id variant;
5484 /* For each variable within each component declaration create a GCC field
5485 and add it to the list, skipping any pragmas in the list. */
5491 {
5496 else
5497 {
5501 /* If this is the _Tag field, put it before any discriminants,
5502 instead of after them as is the case for all other fields.
5503 Ignore field of void type if only annotating. */
5506 else
5507 {
5510 }
5511 }
5514 }
5516 /* At the end of the component list there may be a variant part. */
5519 /* If this is an unchecked union, each variant must have exactly one
5520 component, each of which becomes one component of this union. */
5527 {
5528 component_decl
5532 definition);
5536 }
5538 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
5539 mutually exclusive and should go in the same memory. To do this we need
5540 to treat each variant as a record whose elements are created from the
5541 component list for the variant. So here we create the records from the
5542 lists for the variants and put them all into the QUAL_UNION_TYPE. */
5544 {
5546 Node_Id variant;
5548 tree gnu_union_field;
5551 tree gnu_var_name
5552 = concat_id_with_name
5566 {
5568 tree gnu_inner_name;
5569 tree gnu_qual;
5577 /* Set the alignment of the inner type in case we need to make
5578 inner objects into bitfields, but then clear it out
5579 so the record actually gets only the alignment required. */
5583 /* Similarly, if the outer record has a size specified and all fields
5584 have record rep clauses, we can propagate the size into the
5585 variant part. */
5587 {
5591 }
5604 (all_rep_and_size
5606 (all_rep_and_size
5614 }
5616 /* We use to delete the empty variants from the end. However,
5617 we no longer do that because we need them to generate complete
5618 debugging information for the variant record. Otherwise,
5619 the union type definition will be missing the fields associated
5620 to these empty variants. */
5622 /* Only make the QUAL_UNION_TYPE if there are any non-empty variants. */
5624 {
5626 {
5630 }
5635 gnu_union_field
5637 packed,
5644 }
5645 }
5647 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
5648 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do this
5649 in a separate pass since we want to handle the discriminants but can't
5650 play with them until we've used them in debugging data above.
5652 ??? Note: if we then reorder them, debugging information will be wrong,
5653 but there's nothing that can be done about this at the moment. */
5656 {
5658 {
5663 else
5669 }
5670 else
5671 {
5674 }
5675 }
5677 /* If we have any items in our rep'ed field list, it is not the case that all
5678 the fields in the record have rep clauses, and P_REP_LIST is nonzero,
5679 set it and ignore the items. Otherwise, sort the fields by bit position
5680 and put them into their own record if we have any fields without
5681 rep clauses. */
5685 {
5686 tree gnu_rep_type
5692 /* Set/abuse DECL_FCONTEXT to increasing integers so we have a
5693 stable sort. */
5696 {
5699 }
5703 /* Put the fields in the list in order of increasing position, which
5704 means we start from the end. */
5707 {
5712 }
5715 {
5721 }
5722 else
5723 {
5726 }
5727 }
5734 }
5735 \f
5736 /* Called via qsort from the above. Returns -1, 1, depending on the
5737 bit positions and ordinals of the two fields. */
5739 static int
5741 {
5746 return
5751 else
5753 }
5754 \f
5755 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
5756 placed into an Esize, Component_Bit_Offset, or Component_Size value
5757 in the GNAT tree. */
5759 static Uint
5761 {
5763 TCode tcode;
5768 /* See if we've already saved the value for this node. */
5772 /* If we do not return inside this switch, TCODE will be set to the
5773 code to use for a Create_Node operand and LEN (set above) will be
5774 the number of recursive calls for us to make. */
5777 {
5782 /* This may have come from a conversion from some smaller type,
5783 so ensure this is in bitsizetype. */
5786 /* For negative values, use NEGATE_EXPR of the supplied value. */
5788 {
5789 /* The ridiculous code below is to handle the case of the largest
5790 negative integer. */
5793 tree temp;
5796 {
5797 negative_size
5800 bitsize_one_node));
5802 }
5809 }
5816 /* This peculiar test is to make sure that the size fits in an int
5817 on machines where HOST_WIDE_INT is not "int". */
5820 else
5824 /* The only case we handle here is a simple discriminant reference. */
5832 else
5838 /* Now just list the operations we handle. */
5870 }
5872 /* Now get each of the operands that's relevant for this code. If any
5873 cannot be expressed as a repinfo node, say we can't. */
5878 {
5882 }
5887 }
5889 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding
5890 GCC type, set Component_Bit_Offset and Esize to the position and size
5891 used by Gigi. */
5893 static void
5895 {
5896 tree gnu_list;
5897 tree gnu_entry;
5898 Entity_Id gnat_field;
5900 /* We operate by first making a list of all fields and their positions
5901 (we can get the sizes easily at any time) by a recursive call
5902 and then update all the sizes into the tree. */
5905 BIGGEST_ALIGNMENT);
5912 {
5916 gnu_list);
5919 {
5921 {
5922 /* In this mode the tag and parent components have not been
5923 generated, so we add the appropriate offset to each
5924 component. For a component appearing in the current
5925 extension, the offset is the size of the parent. */
5928 parent_offset
5930 bitsizetype);
5931 else
5933 }
5935 Set_Component_Bit_Offset
5937 annotate_value
5942 parent_offset)));
5946 }
5949 {
5950 /* If there is no gnu_entry, this is an inherited component whose
5951 position is the same as in the parent type. */
5952 Set_Component_Bit_Offset
5957 }
5958 }
5959 }
5961 /* Scan all fields in GNU_TYPE and build entries where TREE_PURPOSE is the
5962 FIELD_DECL and TREE_VALUE a TREE_LIST with TREE_PURPOSE being the byte
5963 position and TREE_VALUE being a TREE_LIST with TREE_PURPOSE the value to be
5964 placed into DECL_OFFSET_ALIGN and TREE_VALUE the bit position. GNU_POS is
5965 to be added to the position, GNU_BITPOS to the bit position, OFFSET_ALIGN is
5966 the present value of DECL_OFFSET_ALIGN and GNU_LIST is a list of the entries
5967 so far. */
5969 static tree
5972 {
5973 tree gnu_field;
5978 {
5983 unsigned int our_offset_align
5986 gnu_result
5991 NULL_TREE),
5992 gnu_result);
5995 gnu_result
5998 our_offset_align);
5999 }
6002 }
6003 \f
6004 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
6005 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
6006 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
6007 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
6008 for the size of a field. COMPONENT_P is true if we are being called
6009 to process the Component_Size of GNAT_OBJECT. This is used for error
6010 message handling and to indicate to use the object size of GNU_TYPE.
6011 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
6012 it means that a size of zero should be treated as an unspecified size. */
6014 static tree
6017 {
6018 Node_Id gnat_error_node;
6019 tree type_size
6021 tree size;
6023 /* Find the node to use for errors. */
6030 else
6033 /* Return 0 if no size was specified, either because Esize was not Present or
6034 the specified size was zero. */
6038 /* Get the size as a tree. Give an error if a size was specified, but cannot
6039 be represented as in sizetype. */
6042 {
6047 }
6049 /* Ignore a negative size since that corresponds to our back-annotation.
6050 Also ignore a zero size unless a size clause exists. */
6054 /* The size of objects is always a multiple of a byte. */
6057 {
6061 else
6065 }
6067 /* If this is an integral type or a packed array type, the front-end has
6068 verified the size, so we need not do it here (which would entail
6069 checking against the bounds). However, if this is an aliased object, it
6070 may not be smaller than the type of the object. */
6075 /* If the object is a record that contains a template, add the size of
6076 the template to the specified size. */
6081 /* Modify the size of the type to be that of the maximum size if it has a
6082 discriminant or the size of a thin pointer if this is a fat pointer. */
6088 /* If this is an access type, the minimum size is that given by the smallest
6089 integral mode that's valid for pointers. */
6091 {
6097 ;
6100 }
6102 /* If the size of the object is a constant, the new size must not be
6103 smaller. */
6107 {
6109 post_error_ne_tree
6112 else
6119 post_error_ne_tree_2
6129 }
6132 }
6133 \f
6134 /* Similarly, but both validate and process a value of RM_Size. This
6135 routine is only called for types. */
6137 static void
6139 {
6140 /* Only give an error if a Value_Size clause was explicitly given.
6141 Otherwise, we'd be duplicating an error on the Size clause. */
6142 Node_Id gnat_attr_node
6145 tree size;
6147 /* Get the size as a tree. Do nothing if none was specified, either
6148 because RM_Size was not Present or if the specified size was zero.
6149 Give an error if a size was specified, but cannot be represented as
6150 in sizetype. */
6156 {
6159 gnat_entity);
6162 }
6164 /* Ignore a negative size since that corresponds to our back-annotation.
6165 Also ignore a zero size unless a size clause exists, a Value_Size
6166 clause exists, or this is an integer type, in which case the
6167 front end will have always set it. */
6174 /* If the old size is self-referential, get the maximum size. */
6178 /* If the size of the object is a constant, the new size must not be
6179 smaller (the front end checks this for scalar types). */
6184 {
6186 post_error_ne_tree
6191 }
6193 /* Otherwise, set the RM_Size. */
6204 }
6205 \f
6206 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
6207 If TYPE is the best type, return it. Otherwise, make a new type. We
6208 only support new integral and pointer types. BIASED_P is nonzero if
6209 we are making a biased type. */
6211 static tree
6213 {
6214 tree new_type;
6218 /* If size indicates an error, just return TYPE to avoid propagating the
6219 error. Likewise if it's too large to represent. */
6225 {
6228 /* Only do something if the type is not already the proper size and is
6229 not a packed array type. */
6241 new_type
6253 /* Do something if this is a fat pointer, in which case we
6254 may need to return the thin pointer. */
6256 return
6257 build_pointer_type
6262 /* Only do something if this is a thin pointer, in which case we
6263 may need to return the fat pointer. */
6265 return
6272 }
6275 }
6276 \f
6277 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
6278 a type or object whose present alignment is ALIGN. If this alignment is
6279 valid, return it. Otherwise, give an error and return ALIGN. */
6281 static unsigned int
6283 {
6287 #ifndef MAX_OFILE_ALIGNMENT
6288 #define MAX_OFILE_ALIGNMENT BIGGEST_ALIGNMENT
6289 #endif
6294 /* Don't worry about checking alignment if alignment was not specified
6295 by the source program and we already posted an error for this entity. */
6300 /* Within GCC, an alignment is an integer, so we must make sure a
6301 value is specified that fits in that range. Also, alignments of
6302 more than MAX_OFILE_ALIGNMENT can't be supported. */
6316 else
6320 }
6321 \f
6322 /* Verify that OBJECT, a type or decl, is something we can implement
6323 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
6324 if we require atomic components. */
6326 static void
6328 {
6330 Node_Id gnat_node;
6333 tree size;
6335 /* There are three case of what OBJECT can be. It can be a type, in which
6336 case we take the size, alignment and mode from the type. It can be a
6337 declaration that was indirect, in which case the relevant values are
6338 that of the type being pointed to, or it can be a normal declaration,
6339 in which case the values are of the decl. The code below assumes that
6340 OBJECT is either a type or a decl. */
6342 {
6346 }
6348 {
6352 }
6353 else
6354 {
6358 }
6360 /* Consider all floating-point types atomic and any types that that are
6361 represented by integers no wider than a machine word. */
6368 /* For the moment, also allow anything that has an alignment equal
6369 to its size and which is smaller than a word. */
6377 {
6385 }
6390 else
6393 }
6394 \f
6395 /* Check if FTYPE1 and FTYPE2, two potentially different function type nodes,
6396 have compatible signatures so that a call using one type may be safely
6397 issued if the actual target function type is the other. Return 1 if it is
6398 the case, 0 otherwise, and post errors on the incompatibilities.
6400 This is used when an Ada subprogram is mapped onto a GCC builtin, to ensure
6401 that calls to the subprogram will have arguments suitable for the later
6402 underlying builtin expansion. */
6404 static int
6406 {
6407 /* As of now, we only perform very trivial tests and consider it's the
6408 programmer's responsibility to ensure the type correctness in the Ada
6409 declaration, as in the regular Import cases.
6411 Mismatches typically result in either error messages from the builtin
6412 expander, internal compiler errors, or in a real call sequence. This
6413 should be refined to issue diagnostics helping error detection and
6414 correction. */
6416 /* Almost fake test, ensuring a use of each argument. */
6421 }
6422 \f
6423 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new type
6424 with all size expressions that contain F updated by replacing F with R.
6425 This is identical to GCC's substitute_in_type except that it knows about
6426 TYPE_INDEX_TYPE. If F is NULL_TREE, always make a new RECORD_TYPE, even if
6427 nothing has changed. */
6429 tree
6431 {
6433 tree tem;
6436 {
6443 {
6452 SET_TYPE_INDEX_TYPE
6455 }
6462 {
6476 }
6490 /* Don't know how to do these yet. */
6494 {
6508 /* If we had bounded the sizes of T by a constant, bound the sizes of
6509 NEW by the same constant. */
6519 }
6524 {
6525 tree field;
6526 bool changed_field
6533 /* Start out with no fields, make new fields, and chain them
6534 in. If we haven't actually changed the type of any field,
6535 discard everything we've done and return the old type. */
6541 {
6552 /* If this is an internal field and the type of this field is
6553 a UNION_TYPE or RECORD_TYPE with no elements, ignore it. If
6554 the type just has one element, treat that as the field.
6555 But don't do this if we are processing a QUAL_UNION_TYPE. */
6560 {
6565 {
6566 tree next_new_field
6569 /* Make sure omitting the union doesn't change
6570 the layout. */
6573 }
6574 }
6581 /* If the size of the old field was set at a constant,
6582 propagate the size in case the type's size was variable.
6583 (This occurs in the case of a variant or discriminated
6584 record with a default size used as a field of another
6585 record.) */
6594 {
6600 /* Do the substitution inside the qualifier and if we find
6601 that this field will not be present, omit it. */
6606 }
6610 else
6615 /* If this is a qualified type and this field will always be
6616 present, we are done. */
6620 }
6622 /* If this used to be a qualified union type, but we now know what
6623 field will be present, make this a normal union. */
6634 /* If the size was originally a constant use it. */
6637 {
6641 }
6644 }
6648 }
6649 }
6650 \f
6651 /* Return the "RM size" of GNU_TYPE. This is the actual number of bits
6652 needed to represent the object. */
6654 tree
6656 {
6657 /* For integer types, this is the precision. For record types, we store
6658 the size explicitly. For other types, this is just the size. */
6664 /* Return the rm_size of the actual data plus the size of the template. */
6665 return
6675 else
6677 }
6678 \f
6679 /* Return an identifier representing the external name to be used for
6680 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
6681 and the specified suffix. */
6683 tree
6685 {
6694 /* A variable using the Stdcall convention (meaning we are running
6695 on a Windows box) live in a DLL. Here we adjust its name to use
6696 the jump-table, the _imp__NAME contains the address for the NAME
6697 variable. */
6700 {
6707 }
6710 }
6712 /* Return the name to be used for GNAT_ENTITY. If a type, create a
6713 fully-qualified name, possibly with type information encoding.
6714 Otherwise, return the name. */
6716 tree
6718 {
6721 }
6723 /* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
6724 string, return a new IDENTIFIER_NODE that is the concatenation of
6725 the name in GNU_ID and SUFFIX. */
6727 tree
6729 {
6738 }