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1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2005, 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 ****************************************************************************/
55 /* Provide default values for the macros controlling stack checking.
56 This is copied from GCC's expr.h. */
58 #ifndef STACK_CHECK_BUILTIN
59 #define STACK_CHECK_BUILTIN 0
60 #endif
61 #ifndef STACK_CHECK_PROBE_INTERVAL
62 #define STACK_CHECK_PROBE_INTERVAL 4096
63 #endif
64 #ifndef STACK_CHECK_MAX_FRAME_SIZE
65 #define STACK_CHECK_MAX_FRAME_SIZE \
66 (STACK_CHECK_PROBE_INTERVAL - UNITS_PER_WORD)
67 #endif
68 #ifndef STACK_CHECK_MAX_VAR_SIZE
69 #define STACK_CHECK_MAX_VAR_SIZE (STACK_CHECK_MAX_FRAME_SIZE / 100)
70 #endif
72 /* These two variables are used to defer recursively expanding incomplete
73 types while we are processing a record or subprogram type. */
76 static struct incomplete
77 {
79 tree old_type;
80 Entity_Id full_type;
83 /* These two variables are used to defer emission of debug information for
84 nested incomplete record types */
112 /* Given GNAT_ENTITY, an entity in the incoming GNAT tree, return a
113 GCC type corresponding to that entity. GNAT_ENTITY is assumed to
114 refer to an Ada type. */
116 tree
118 {
119 tree gnu_decl;
121 /* The back end never attempts to annotate generic types */
125 /* Convert the ada entity type into a GCC TYPE_DECL node. */
129 }
130 \f
131 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
132 entity, this routine returns the equivalent GCC tree for that entity
133 (an ..._DECL node) and associates the ..._DECL node with the input GNAT
134 defining identifier.
136 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
137 initial value (in GCC tree form). This is optional for variables.
138 For renamed entities, GNU_EXPR gives the object being renamed.
140 DEFINITION is nonzero if this call is intended for a definition. This is
141 used for separate compilation where it necessary to know whether an
142 external declaration or a definition should be created if the GCC equivalent
143 was not created previously. The value of 1 is normally used for a non-zero
144 DEFINITION, but a value of 2 is used in special circumstances, defined in
145 the code. */
147 tree
149 {
150 tree gnu_entity_id;
152 /* Contains the gnu XXXX_DECL tree node which is equivalent to the input
153 GNAT tree. This node will be associated with the GNAT node by calling
154 the save_gnu_tree routine at the end of the `switch' statement. */
156 /* true if we have already saved gnu_decl as a gnat association. */
158 /* Nonzero if we incremented defer_incomplete_level. */
160 /* Nonzero if we incremented defer_debug_level. */
162 /* Nonzero if we incremented force_global. */
164 /* Nonzero if we should check to see if elaborated during processing. */
166 /* Nonzero if we made GNU_DECL and its type here. */
172 Entity_Id gnat_temp;
173 unsigned int esize
183 bool imported_p
188 /* Since a use of an Itype is a definition, process it as such if it
189 is not in a with'ed unit. */
194 {
195 /* Ensure that we are in a subprogram mentioned in the Scope
196 chain of this entity, our current scope is global,
197 or that we encountered a task or entry (where we can't currently
198 accurately check scoping). */
201 {
204 }
208 {
213 gnat_temp
225 && (current_function_decl
227 {
230 }
231 }
233 /* This abort means the entity "gnat_entity" has an incorrect scope,
234 i.e. that its scope does not correspond to the subprogram in which
235 it is declared */
237 }
239 /* If this is entity 0, something went badly wrong. */
242 /* If we've already processed this entity, return what we got last time.
243 If we are defining the node, we should not have already processed it.
244 In that case, we will abort below when we try to save a new GCC tree for
245 this object. We also need to handle the case of getting a dummy type
246 when a Full_View exists. */
249 && (! definition
251 {
258 {
264 }
267 }
269 /* If this is a numeric or enumeral type, or an access type, a nonzero
270 Esize must be specified unless it was specified by the programmer. */
278 /* Likewise, RM_Size must be specified for all discrete and fixed-point
279 types. */
283 /* Get the name of the entity and set up the line number and filename of
284 the original definition for use in any decl we make. */
288 /* If we get here, it means we have not yet done anything with this
289 entity. If we are not defining it here, it must be external,
290 otherwise we should have defined it already. */
297 /* For cases when we are not defining (i.e., we are referencing from
298 another compilation unit) Public entities, show we are at global level
299 for the purpose of computing scopes. Don't do this for components or
300 discriminants since the relevant test is whether or not the record is
301 being defined. But do this for Imported functions or procedures in
302 all cases. */
310 /* Handle any attributes directly attached to the entity. */
314 /* Machine_Attributes on types are expected to be propagated to subtypes.
315 The corresponding Gigi_Rep_Items are only attached to the first subtype
316 though, so we handle the propagation here. */
323 {
325 /* If this is a use of a deferred constant, get its full
326 declaration. */
328 {
333 }
335 /* If we have an external constant that we are not defining,
336 get the expression that is was defined to represent. We
337 may throw that expression away later if it is not a
338 constant.
339 Do not retrieve the expression if it is an aggregate, because
340 in complex instantiation contexts it may not be expanded */
349 /* Ignore deferred constant definitions; they are processed fully in the
350 front-end. For deferred constant references, get the full
351 definition. On the other hand, constants that are renamings are
352 handled like variable renamings. If No_Initialization is set, this is
353 not a deferred constant but a constant whose value is built
354 manually. */
359 {
363 }
366 {
371 }
376 /* We used to special case VMS exceptions here to directly map them to
377 their associated condition code. Since this code had to be masked
378 dynamically to strip off the severity bits, this caused trouble in
379 the GCC/ZCX case because the "type" pointers we store in the tables
380 have to be static. We now don't special case here anymore, and let
381 the regular processing take place, which leaves us with a regular
382 exception data object for VMS exceptions too. The condition code
383 mapping is taken care of by the front end and the bitmasking by the
384 runtime library. */
389 {
390 /* The GNAT record where the component was defined. */
393 /* If the variable is an inherited record component (in the case of
394 extended record types), just return the inherited entity, which
395 must be a FIELD_DECL. Likewise for discriminants.
396 For discriminants of untagged records which have explicit
397 stored discriminants, return the entity for the corresponding
398 stored discriminant. Also use Original_Record_Component
399 if the record has a private extension. */
403 {
404 gnu_decl
409 }
411 /* If the enclosing record has explicit stored discriminants,
412 then it is an untagged record. If the Corresponding_Discriminant
413 is not empty then this must be a renamed discriminant and its
414 Original_Record_Component must point to the corresponding explicit
415 stored discriminant (i.e., we should have taken the previous
416 branch). */
420 {
421 /* A tagged record has no explicit stored discriminants. */
425 gnu_decl
430 }
432 /* If the enclosing record has explicit stored discriminants,
433 then it is an untagged record. If the Corresponding_Discriminant
434 is not empty then this must be a renamed discriminant and its
435 Original_Record_Component must point to the corresponding explicit
436 stored discriminant (i.e., we should have taken the first
437 branch). */
444 /* Otherwise, if we are not defining this and we have no GCC type
445 for the containing record, make one for it. Then we should
446 have made our own equivalent. */
448 {
449 /* ??? If this is in a record whose scope is a protected
450 type and we have an Original_Record_Component, use it.
451 This is a workaround for major problems in protected type
452 handling. */
460 {
461 gnu_decl
467 }
473 }
475 else
476 /* Here we have no GCC type and this is a reference rather than a
477 definition. This should never happen. Most likely the cause is a
478 reference before declaration in the gnat tree for gnat_entity. */
480 }
486 /* Simple variables, loop variables, OUT parameters, and exceptions. */
487 object:
488 {
490 bool const_flag
505 {
509 else
511 }
513 /* Get the type after elaborating the renamed object. */
516 /* If this is a loop variable, its type should be the base type.
517 This is because the code for processing a loop determines whether
518 a normal loop end test can be done by comparing the bounds of the
519 loop against those of the base type, which is presumed to be the
520 size used for computation. But this is not correct when the size
521 of the subtype is smaller than the type. */
525 /* Reject non-renamed objects whose types are unconstrained arrays or
526 any object whose type is a dummy type or VOID_TYPE. */
532 {
535 }
537 /* If an alignment is specified, use it if valid. Note that
538 exceptions are objects but don't have alignments. We must do this
539 before we validate the size, since the alignment can affect the
540 size. */
542 {
548 }
550 /* If we are defining the object, see if it has a Size value and
551 validate it if so. If we are not defining the object and a Size
552 clause applies, simply retrieve the value. We don't want to ignore
553 the clause and it is expected to have been validated already. Then
554 get the new type, if any. */
563 {
564 gnu_type
570 }
572 /* If this object has self-referential size, it must be a record with
573 a default value. We are supposed to allocate an object of the
574 maximum size in this case unless it is a constant with an
575 initializing expression, in which case we can get the size from
576 that. Note that the resulting size may still be a variable, so
577 this may end up with an indirect allocation. */
581 {
583 gnu_size
584 = SUBSTITUTE_PLACEHOLDER_IN_EXPR
587 /* We may have no GNU_EXPR because No_Initialization is
588 set even though there's an Expression. */
593 gnu_size
595 (Etype
597 else
598 {
601 }
602 }
604 /* If the size is zero bytes, make it one byte since some linkers have
605 trouble with zero-sized objects. If the object will have a
606 template, that will make it nonzero so don't bother. Also avoid
607 doing that for an object renaming or an object with an address
608 clause, as we would lose useful information on the view size
609 (e.g. for null array slices) and we are not allocating the object
610 here anyway. */
619 /* If this is an atomic object with no specified size and alignment,
620 but where the size of the type is a constant, set the alignment to
621 the lowest power of two greater than the size, or to the
622 biggest meaningful alignment, whichever is smaller. */
626 {
629 BIGGEST_ALIGNMENT))
631 else
636 }
638 /* If the object is set to have atomic components, find the component
639 type and validate it.
641 ??? Note that we ignore Has_Volatile_Components on objects; it's
642 not at all clear what to do in that case. */
645 {
654 }
656 /* Now check if the type of the object allows atomic access. Note
657 that we must test the type, even if this object has size and
658 alignment to allow such access, because we will be going
659 inside the padded record to assign to the object. We could fix
660 this by always copying via an intermediate value, but it's not
661 clear it's worth the effort. */
665 /* If this is an aliased object with an unconstrained nominal subtype,
666 make a type that includes the template. */
670 {
671 tree gnu_fat
673 tree gnu_temp_type
676 gnu_type
680 }
682 #ifdef MINIMUM_ATOMIC_ALIGNMENT
683 /* If the size is a constant and no alignment is specified, force
684 the alignment to be the minimum valid atomic alignment. The
685 restriction on constant size avoids problems with variable-size
686 temporaries; if the size is variable, there's no issue with
687 atomic access. Also don't do this for a constant, since it isn't
688 necessary and can interfere with constant replacement. Finally,
689 do not do it for Out parameters since that creates an
690 size inconsistency with In parameters. */
699 #endif
701 /* Make a new type with the desired size and alignment, if needed. */
705 /* Make a volatile version of this object's type if we are to
706 make the object volatile. Note that 13.3(19) says that we
707 should treat other types of objects as volatile as well. */
717 /* Convert the expression to the type of the object except in the
718 case where the object's type is unconstrained or the object's type
719 is a padded record whose field is of self-referential size. In
720 the former case, converting will generate unnecessary evaluations
721 of the CONSTRUCTOR to compute the size and in the latter case, we
722 want to only copy the actual data. */
728 && (CONTAINS_PLACEHOLDER_P
732 /* See if this is a renaming. If this is a constant renaming, treat
733 it as a normal variable whose initial value is what is being
734 renamed. We cannot do this if the type is unconstrained or
735 class-wide.
737 Otherwise, if what we are renaming is a reference, we can simply
738 return a stabilized version of that reference, after forcing any
739 SAVE_EXPRs to be evaluated. But, if this is at global level, we
740 can only do this if we know no SAVE_EXPRs will be made.
742 Otherwise, make this into a constant pointer to the object we are
743 to rename. */
746 {
747 /* If the renamed object had padding, strip off the reference
748 to the inner object and reset our type. */
752 && (TYPE_IS_PADDING_P
754 {
757 }
765 ;
767 /* If this is a declaration or reference that we can stabilize,
768 just use that declaration or reference as this entity unless
769 the latter has to be materialized. */
775 {
780 }
782 /* Otherwise, make this into a constant pointer to the object we
783 are to rename and attach the object to the pointer. We need
784 to stabilize too since the renaming evaluation may directly
785 reference the renamed object instead of the pointer we will
786 attach it to. We don't want variables in the expression to
787 be evaluated every time the renaming is used, since their
788 value may change in between. */
789 else
790 {
799 {
800 /* If the original expression had side effects, put a
801 SAVE_EXPR around this whole thing. */
806 }
810 }
811 }
813 /* If this is an aliased object whose nominal subtype is unconstrained,
814 the object is a record that contains both the template and
815 the object. If there is an initializer, it will have already
816 been converted to the right type, but we need to create the
817 template if there is no initializer. */
820 /* Beware that padding might have been introduced
821 via maybe_pad_type above. */
824 == RECORD_TYPE
825 && TYPE_CONTAINS_TEMPLATE_P
828 {
829 tree template_field
834 gnu_expr
835 = gnat_build_constructor
837 tree_cons
841 NULL_TREE),
842 NULL_TREE));
843 }
845 /* If this is a pointer and it does not have an initializing
846 expression, initialize it to NULL, unless the object is
847 imported. */
853 /* If we are defining the object and it has an Address clause we must
854 get the address expression from the saved GCC tree for the
855 object if the object has a Freeze_Node. Otherwise, we elaborate
856 the address expression here since the front-end has guaranteed
857 in that case that the elaboration has no effects. Note that
858 only the latter mechanism is currently in use. */
860 {
861 tree gnu_address
867 /* Ignore the size. It's either meaningless or was handled
868 above. */
875 /* If we don't have an initializing expression for the underlying
876 variable, the initializing expression for the pointer is the
877 specified address. Otherwise, we have to make a COMPOUND_EXPR
878 to assign both the address and the initial value. */
881 else
882 gnu_expr
884 build_binary_op
887 gnu_address),
888 gnu_expr),
889 gnu_address);
890 }
892 /* If it has an address clause and we are not defining it, mark it
893 as an indirect object. Likewise for Stdcall objects that are
894 imported. */
898 {
902 }
904 /* If we are at top level and this object is of variable size,
905 make the actual type a hidden pointer to the real type and
906 make the initializer be a memory allocation and initialization.
907 Likewise for objects we aren't defining (presumed to be
908 external references from other packages), but there we do
909 not set up an initialization.
911 If the object's size overflows, make an allocator too, so that
912 Storage_Error gets raised. Note that we will never free
913 such memory, so we presume it never will get allocated. */
918 || (gnu_size
922 {
928 /* In case this was a aliased object whose nominal subtype is
929 unconstrained, the pointer above will be a thin pointer and
930 build_allocator will automatically make the template.
932 If we have a template initializer only (that we made above),
933 pretend there is none and rely on what build_allocator creates
934 again anyway. Otherwise (if we have a full initializer), get
935 the data part and feed that to build_allocator.
937 If we are elaborating a mutable object, tell build_allocator to
938 ignore a possibly simpler size from the initializer, if any, as
939 we must allocate the maximum possible size in this case. */
942 {
947 {
948 gnu_alloc_type
955 else
956 gnu_expr
957 = build_component_ref
961 }
967 gnat_entity);
971 }
972 else
973 {
976 }
977 }
979 /* If this object would go into the stack and has an alignment
980 larger than the default largest alignment, make a variable
981 to hold the "aligning type" with a modified initial value,
982 if any, then point to it and make that the value of this
983 variable, which is now indirect. */
986 {
987 tree gnu_new_type
990 tree gnu_new_var;
992 gnu_new_var
998 add_stmt_with_node
1000 build_component_ref
1003 gnu_expr),
1004 gnat_entity);
1007 gnu_expr
1008 = build_unary_op
1016 }
1022 /* Convert the expression to the type of the object except in the
1023 case where the object's type is unconstrained or the object's type
1024 is a padded record whose field is of self-referential size. In
1025 the former case, converting will generate unnecessary evaluations
1026 of the CONSTRUCTOR to compute the size and in the latter case, we
1027 want to only copy the actual data. */
1033 && (CONTAINS_PLACEHOLDER_P
1037 /* If this name is external or there was a name specified, use it,
1038 unless this is a VMS exception object since this would conflict
1039 with the symbol we need to export in addition. Don't use the
1040 Interface_Name if there is an address clause (see CD30005). */
1049 /* If this is constant initialized to a static constant and the
1050 object has an aggregate type, force it to be statically
1051 allocated. */
1067 {
1070 }
1072 /* If we have an address clause and we've made this indirect, it's
1073 not enough to merely mark the type as volatile since volatile
1074 references only conflict with other volatile references while this
1075 reference must conflict with all other references. So ensure that
1076 the dereferenced value has alias set 0. */
1085 STACK_CHECK_MAX_VAR_SIZE))))
1090 gnat_entity);
1092 /* If this is a public constant or we're not optimizing and we're not
1093 making a VAR_DECL for it, make one just for export or debugger
1094 use. Likewise if the address is taken or if the object or type is
1095 aliased. */
1102 {
1103 tree gnu_corr_var
1109 }
1111 /* If this is declared in a block that contains a block with an
1112 exception handler, we must force this variable in memory to
1113 suppress an invalid optimization. */
1118 /* Back-annotate the Alignment of the object if not already in the
1119 tree. Likewise for Esize if the object is of a constant size.
1120 But if the "object" is actually a pointer to an object, the
1121 alignment and size are the same as the type, so don't back-annotate
1122 the values for the pointer. */
1129 {
1134 gnu_back_size
1139 }
1140 }
1144 /* Return a TYPE_DECL for "void" that we previously made. */
1149 /* A special case, for the types Character and Wide_Character in
1150 Standard, we do not list all the literals. So if the literals
1151 are not specified, make this an unsigned type. */
1153 {
1156 }
1158 /* Normal case of non-character type, or non-Standard character type */
1159 {
1160 /* Here we have a list of enumeral constants in First_Literal.
1161 We make a CONST_DECL for each and build into GNU_LITERAL_LIST
1162 the list to be places into TYPE_FIELDS. Each node in the list
1163 is a TREE_LIST node whose TREE_VALUE is the literal name
1164 and whose TREE_PURPOSE is the value of the literal.
1166 Esize contains the number of bits needed to represent the enumeral
1167 type, Type_Low_Bound also points to the first literal and
1168 Type_High_Bound points to the last literal. */
1170 Entity_Id gnat_literal;
1175 else
1183 {
1185 gnu_type);
1186 tree gnu_literal
1194 }
1198 /* Note that the bounds are updated at the end of this function
1199 because to avoid an infinite recursion when we get the bounds of
1200 this type, since those bounds are objects of this type. */
1201 }
1207 /* For integer types, just make a signed type the appropriate number
1208 of bits. */
1213 /* For modular types, make the unsigned type of the proper number of
1214 bits and then set up the modulus, if required. */
1215 {
1217 tree gnu_modulus;
1223 /* Find the smallest mode at least ESIZE bits wide and make a class
1224 using that mode. */
1229 ;
1235 /* Get the modulus in this type. If it overflows, assume it is because
1236 it is equal to 2**Esize. Note that there is no overflow checking
1237 done on unsigned type, so we detect the overflow by looking for
1238 a modulus of zero, which is otherwise invalid. */
1242 {
1247 }
1249 /* If we have to set TYPE_PRECISION different from its natural value,
1250 make a subtype to do do. Likewise if there is a modulus and
1251 it is not one greater than TYPE_MAX_VALUE. */
1255 {
1272 }
1273 }
1282 /* For integral subtypes, we make a new INTEGER_TYPE. Note
1283 that we do not want to call build_range_type since we would
1284 like each subtype node to be distinct. This will be important
1285 when memory aliasing is implemented.
1287 The TREE_TYPE field of the INTEGER_TYPE we make points to the
1288 parent type; this fact is used by the arithmetic conversion
1289 functions.
1291 We elaborate the Ancestor_Subtype if it is not in the current
1292 unit and one of our bounds is non-static. We do this to ensure
1293 consistent naming in the case where several subtypes share the same
1294 bounds by always elaborating the first such subtype first, thus
1295 using its name. */
1307 {
1310 }
1318 gnat_entity,
1325 gnat_entity,
1329 /* One of the above calls might have caused us to be elaborated,
1330 so don't blow up if so. */
1332 {
1335 }
1340 /* This should be an unsigned type if the lower bound is constant
1341 and non-negative or if the base type is unsigned; a signed type
1342 otherwise. */
1352 /* If the type we are dealing with is to represent a packed array,
1353 we need to have the bits left justified on big-endian targets
1354 and right justified on little-endian targets. We also need to
1355 ensure that when the value is read (e.g. for comparison of two
1356 such values), we only get the good bits, since the unused bits
1357 are uninitialized. Both goals are accomplished by wrapping the
1358 modular value in an enclosing struct. */
1360 {
1362 tree gnu_field;
1371 /* Create a stripped-down declaration of the original type, mainly
1372 for debugging. */
1376 /* Don't notify the field as "addressable", since we won't be taking
1377 it's address and it would prevent create_field_decl from making a
1378 bitfield. */
1385 }
1390 /* If this is a VAX floating-point type, use an integer of the proper
1391 size. All the operations will be handled with ASM statements. */
1393 {
1398 sizetype));
1400 }
1402 /* The type of the Low and High bounds can be our type if this is
1403 a type from Standard, so set them at the end of the function. */
1411 {
1414 }
1416 {
1443 /* One of the above calls might have caused us to be elaborated,
1444 so don't blow up if so. */
1446 {
1449 }
1452 }
1455 /* Array and String Types and Subtypes
1457 Unconstrained array types are represented by E_Array_Type and
1458 constrained array types are represented by E_Array_Subtype. There
1459 are no actual objects of an unconstrained array type; all we have
1460 are pointers to that type.
1462 The following fields are defined on array types and subtypes:
1464 Component_Type Component type of the array.
1465 Number_Dimensions Number of dimensions (an int).
1466 First_Index Type of first index. */
1470 {
1476 int firstdim
1478 int nextdim
1484 tree gnu_max_size_unit;
1486 Entity_Id gnat_ind_subtype;
1487 Entity_Id gnat_ind_base_subtype;
1488 tree gnu_template_reference;
1489 tree tem;
1497 /* Make a node for the array. If we are not defining the array
1498 suppress expanding incomplete types and save the node as the type
1499 for GNAT_ENTITY. */
1502 {
1503 defer_incomplete_level++;
1510 }
1512 /* Build the fat pointer type. Use a "void *" object instead of
1513 a pointer to the array type since we don't have the array type
1514 yet (it will reference the fat pointer via the bounds). */
1517 ptr_void_type_node,
1520 gnu_ptr_template,
1523 /* Make sure we can put this into a register. */
1527 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1528 is the fat pointer. This will be used to access the individual
1529 fields once we build them. */
1533 gnu_template_reference
1537 /* Now create the GCC type for each index and add the fields for
1538 that index to the template. */
1540 gnat_ind_base_subtype
1546 {
1548 tree gnu_ind_subtype
1550 tree gnu_base_subtype
1552 tree gnu_base_min
1554 tree gnu_base_max
1558 /* Make the FIELD_DECLs for the minimum and maximum of this
1559 type and then make extractions of that field from the
1560 template. */
1563 gnu_ind_subtype,
1567 gnu_ind_subtype,
1576 /* We can't use build_component_ref here since the template
1577 type isn't complete yet. */
1580 NULL_TREE);
1583 NULL_TREE);
1586 /* Make a range type with the new ranges, but using
1587 the Ada subtype. Then we convert to sizetype. */
1593 /* Update the maximum size of the array, in elements. */
1594 gnu_max_size
1598 gnu_base_min)));
1602 }
1605 gnu_template_fields
1608 /* Install all the fields into the template. */
1613 /* Now make the array of arrays and update the pointer to the array
1614 in the fat pointer. Note that it is the first field. */
1618 /* Get and validate any specified Component_Size, but if Packed,
1619 ignore it since the front end will have taken care of it. */
1620 gnu_comp_size
1622 gnat_entity,
1630 /* If the component type is a RECORD_TYPE that has a self-referential
1631 size, use the maxium size. */
1637 {
1641 }
1647 /* If Component_Size is not already specified, annotate it with the
1648 size of the component. */
1658 gnu_max_size),
1662 {
1666 /* If the type below this an multi-array type, then this
1667 does not not have aliased components.
1669 ??? Otherwise, for now, we say that any component of aggregate
1670 type is addressable because the front end may take 'Reference
1671 of it. But we have to make it addressable if it must be passed
1672 by reference or it that is the default. */
1678 }
1680 /* If an alignment is specified, use it if valid. But ignore it for
1681 types that represent the unpacked base type for packed arrays. */
1684 {
1689 }
1695 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
1696 corresponding fat pointer. */
1703 /* If the maximum size doesn't overflow, use it. */
1718 /* Create a record type for the object and its template and
1719 set the template at a negative offset. */
1731 /* Give the thin pointer type a name. */
1735 gnat_entity);
1736 }
1742 /* This is the actual data type for array variables. Multidimensional
1743 arrays are implemented in the gnu tree as arrays of arrays. Note
1744 that for the moment arrays which have sparse enumeration subtypes as
1745 index components create sparse arrays, which is obviously space
1746 inefficient but so much easier to code for now.
1748 Also note that the subtype never refers to the unconstrained
1749 array type, which is somewhat at variance with Ada semantics.
1751 First check to see if this is simply a renaming of the array
1752 type. If so, the result is the array type. */
1757 else
1758 {
1761 int first_dim
1764 int next_dim
1766 Entity_Id gnat_ind_subtype;
1767 Entity_Id gnat_ind_base_subtype;
1772 tree gnu_max_size_unit;
1776 /* First create the gnu types for each index. Create types for
1777 debugging information to point to the index types if the
1778 are not integer types, have variable bounds, or are
1779 wider than sizetype. */
1782 gnat_ind_base_subtype
1788 {
1789 tree gnu_index_subtype
1791 tree gnu_min
1793 tree gnu_max
1795 tree gnu_base_subtype
1797 tree gnu_base_min
1799 tree gnu_base_max
1802 tree gnu_base_base_min
1804 tree gnu_base_base_max
1806 tree gnu_high;
1807 tree gnu_this_max;
1809 /* If the minimum and maximum values both overflow in
1810 SIZETYPE, but the difference in the original type
1811 does not overflow in SIZETYPE, ignore the overflow
1812 indications. */
1820 && (!TREE_OVERFLOW
1828 /* Similarly, if the range is null, use bounds of 1..0 for
1829 the sizetype bounds. */
1841 /* Now compute the size of this bound. We need to provide
1842 GCC with an upper bound to use but have to deal with the
1843 "superflat" case. There are three ways to do this. If we
1844 can prove that the array can never be superflat, we can
1845 just use the high bound of the index subtype. If we can
1846 prove that the low bound minus one can't overflow, we
1847 can do this as MAX (hb, lb - 1). Otherwise, we have to use
1848 the expression hb >= lb ? hb : lb - 1. */
1851 /* See if the base array type is already flat. If it is, we
1852 are probably compiling an ACVC test, but it will cause the
1853 code below to malfunction if we don't handle it specially. */
1861 /* If gnu_high is now an integer which overflowed, the array
1862 cannot be superflat. */
1869 else
1870 gnu_high
1871 = build_cond_expr
1879 /* Also compute the maximum size of the array. Here we
1880 see if any constraint on the index type of the base type
1881 can be used in the case of self-referential bound on
1882 the index type of the subtype. We look for a non-"infinite"
1883 and non-self-referential bound from any type involved and
1884 handle each bound separately. */
1909 gnu_this_max
1913 gnu_base_min)),
1914 size_zero_node);
1920 gnu_max_size
1934 }
1936 /* Then flatten: create the array of arrays. */
1940 /* One of the above calls might have caused us to be elaborated,
1941 so don't blow up if so. */
1943 {
1946 }
1948 /* Get and validate any specified Component_Size, but if Packed,
1949 ignore it since the front end will have taken care of it. */
1950 gnu_comp_size
1952 gnat_entity,
1957 /* If the component type is a RECORD_TYPE that has a self-referential
1958 size, use the maxium size. */
1964 {
1969 }
1983 {
1986 /* If the type below this an multi-array type, then this
1987 does not not have aliased components.
1989 ??? Otherwise, for now, we say that any component of aggregate
1990 type is addressable because the front end may take 'Reference
1991 of it. But we have to make it addressable if it must be passed
1992 by reference or it that is the default. */
1998 }
2000 /* If we are at file level and this is a multi-dimensional array, we
2001 need to make a variable corresponding to the stride of the
2002 inner dimensions. */
2004 {
2006 tree gnu_arr_type;
2012 {
2020 /* ??? For now, store the size as a multiple of the
2021 alignment of the element type in bytes so that we
2022 can see the alignment from the tree. */
2024 = build_binary_op
2026 elaborate_expression_1
2035 }
2036 }
2038 /* If we need to write out a record type giving the names of
2039 the bounds, do it now. */
2041 {
2044 tree gnu_field;
2050 {
2051 tree gnu_type_name
2058 integer_type_node,
2059 gnu_bound_rec_type,
2063 }
2067 }
2074 /* If our size depends on a placeholder and the maximum size doesn't
2075 overflow, use it. */
2082 {
2088 }
2090 /* Set our alias set to that of our base type. This gives all
2091 array subtypes the same alias set. */
2093 }
2095 /* If this is a packed type, make this type the same as the packed
2096 array type, but do some adjusting in the type first. */
2099 {
2100 Entity_Id gnat_index;
2101 tree gnu_inner_type;
2103 /* First finish the type we had been making so that we output
2104 debugging information for it */
2105 gnu_type
2108 | (TYPE_QUAL_VOLATILE
2116 /* Save it as our equivalent in case the call below elaborates
2117 this type again. */
2131 /* We need to point the type we just made to our index type so
2132 the actual bounds can be put into a template. */
2138 {
2140 {
2141 /* The TYPE_ACTUAL_BOUNDS field is also used for the modulus.
2142 If it is, we need to make another type. */
2144 {
2145 tree gnu_subtype;
2162 }
2165 }
2171 SET_TYPE_ACTUAL_BOUNDS
2178 SET_TYPE_ACTUAL_BOUNDS
2185 }
2186 }
2188 /* Abort if packed array with no packed array type field set. */
2189 else
2195 /* Create the type for a string literal. */
2196 {
2197 Entity_Id gnat_full_type
2202 tree gnu_string_array_type
2204 tree gnu_string_index_type
2207 tree gnu_lower_bound
2212 tree gnu_upper_bound
2214 gnu_lower_bound,
2216 tree gnu_range_type
2219 tree gnu_index_type
2224 gnu_range_type);
2226 gnu_type
2228 gnu_index_type);
2230 }
2233 /* Record Types and Subtypes
2235 The following fields are defined on record types:
2237 Has_Discriminants True if the record has discriminants
2238 First_Discriminant Points to head of list of discriminants
2239 First_Entity Points to head of list of fields
2240 Is_Tagged_Type True if the record is tagged
2242 Implementation of Ada records and discriminated records:
2244 A record type definition is transformed into the equivalent of a C
2245 struct definition. The fields that are the discriminants which are
2246 found in the Full_Type_Declaration node and the elements of the
2247 Component_List found in the Record_Type_Definition node. The
2248 Component_List can be a recursive structure since each Variant of
2249 the Variant_Part of the Component_List has a Component_List.
2251 Processing of a record type definition comprises starting the list of
2252 field declarations here from the discriminants and the calling the
2253 function components_to_record to add the rest of the fields from the
2254 component list and return the gnu type node. The function
2255 components_to_record will call itself recursively as it traverses
2256 the tree. */
2260 {
2261 gnu_type
2262 = build_complex_type
2263 (get_unpadded_type
2266 (Component_List
2267 (Type_Definition
2271 }
2273 {
2276 Entity_Id gnat_field;
2277 tree gnu_field;
2279 tree gnu_get_parent;
2286 bool is_extension
2290 /* See if all fields have a rep clause. Stop when we find one
2291 that doesn't. */
2300 /* If this is a record extension, go a level further to find the
2301 record definition. Also, verify we have a Parent_Subtype. */
2303 {
2310 }
2312 /* Make a node for the record. If we are not defining the record,
2313 suppress expanding incomplete types and save the node as the type
2314 for GNAT_ENTITY. We use the same RECORD_TYPE as for a dummy type
2315 and reset TYPE_DUMMY_P to show it's no longer a dummy.
2317 It is very tempting to delay resetting this bit until we are done
2318 with completing the type, e.g. to let possible intermediate
2319 elaboration of access types designating the record know it is not
2320 complete and arrange for update_pointer_to to fix things up later.
2322 It would be wrong, however, because dummy types are expected only
2323 to be created for Ada incomplete or private types, which is not
2324 what we have here. Doing so would make other parts of gigi think
2325 we are dealing with a really incomplete or private type, and have
2326 nasty side effects, typically on the generation of the associated
2327 debugging information. */
2338 {
2339 defer_incomplete_level++;
2346 }
2348 /* If both a size and rep clause was specified, put the size in
2349 the record type now so that it can get the proper mode. */
2353 /* Always set the alignment here so that it can be used to
2354 set the mode, if it is making the alignment stricter. If
2355 it is invalid, it will be checked again below. If this is to
2356 be Atomic, choose a default alignment of a word unless we know
2357 the size and it's smaller. */
2366 /* If we have a Parent_Subtype, make a field for the parent. If
2367 this record has rep clauses, force the position to zero. */
2369 {
2370 tree gnu_parent;
2372 /* A major complexity here is that the parent subtype will
2373 reference our discriminants. But those must reference
2374 the parent component of this record. So here we will
2375 initialize each of those components to a COMPONENT_REF.
2376 The first operand of that COMPONENT_REF is another
2377 COMPONENT_REF which will be filled in below, once
2378 the parent type can be safely built. */
2383 NULL_TREE),
2384 NULL_TREE);
2391 save_gnu_tree
2395 gnu_get_parent,
2398 NULL_TREE),
2403 gnu_field_list
2413 }
2415 /* Add the fields for the discriminants into the record. */
2421 {
2422 /* If this is a record extension and this discriminant
2423 is the renaming of another discriminant, we've already
2424 handled the discriminant above. */
2429 gnu_field
2432 /* Make an expression using a PLACEHOLDER_EXPR from the
2433 FIELD_DECL node just created and link that with the
2434 corresponding GNAT defining identifier. Then add to the
2435 list of fields. */
2445 }
2447 /* Put the discriminants into the record (backwards), so we can
2448 know the appropriate discriminant to use for the names of the
2449 variants. */
2452 /* Add the listed fields into the record and finish up. */
2458 {
2460 defer_debug_level++;
2462 defer_debug_incomplete_list
2464 defer_debug_incomplete_list);
2465 }
2467 /* We used to remove the associations of the discriminants and
2468 _Parent for validity checking, but we may need them if there's
2469 Freeze_Node for a subtype used in this record. */
2474 /* If it is a tagged record force the type to BLKmode to insure
2475 that these objects will always be placed in memory. Do the
2476 same thing for limited record types. */
2480 /* If this is a derived type, we must make the alias set of this type
2481 the same as that of the type we are derived from. We assume here
2482 that the other type is already frozen. */
2488 /* Fill in locations of fields. */
2491 /* If there are any entities in the chain corresponding to
2492 components that we did not elaborate, ensure we elaborate their
2493 types if they are Itypes. */
2501 }
2505 /* If an equivalent type is present, that is what we should use.
2506 Otherwise, fall through to handle this like a record subtype
2507 since it may have constraints. */
2510 {
2515 }
2517 /* ... fall through ... */
2521 /* If Cloned_Subtype is Present it means this record subtype has
2522 identical layout to that type or subtype and we should use
2523 that GCC type for this one. The front end guarantees that
2524 the component list is shared. */
2526 {
2530 }
2532 /* Otherwise, first ensure the base type is elaborated. Then, if we are
2533 changing the type, make a new type with each field having the
2534 type of the field in the new subtype but having the position
2535 computed by transforming every discriminant reference according
2536 to the constraints. We don't see any difference between
2537 private and nonprivate type here since derivations from types should
2538 have been deferred until the completion of the private type. */
2539 else
2540 {
2542 tree gnu_base_type;
2543 tree gnu_orig_type;
2548 /* Get the base type initially for its alignment and sizes. But
2549 if it is a padded type, we do all the other work with the
2550 unpadded type. */
2559 {
2562 }
2564 /* When the type has discriminants, and these discriminants
2565 affect the shape of what it built, factor them in.
2567 If we are making a subtype of an Unchecked_Union (must be an
2568 Itype), just return the type.
2570 We can't just use Is_Constrained because private subtypes without
2571 discriminants of full types with discriminants with default
2572 expressions are Is_Constrained but aren't constrained! */
2580 {
2581 Entity_Id gnat_field;
2583 tree gnu_pos_list
2586 BIGGEST_ALIGNMENT);
2587 tree gnu_subst_list
2589 definition);
2590 tree gnu_temp;
2596 gnat_entity);
2608 {
2609 tree gnu_old_field
2612 tree gnu_offset
2614 gnu_pos_list));
2617 tree gnu_field_type
2621 unsigned int offset_align
2624 tree gnu_field;
2626 /* If there was a component clause, the field types must be
2627 the same for the type and subtype, so copy the data from
2628 the old field to avoid recomputation here. Also if the
2629 field is justified modular and the optimization in
2630 gnat_to_gnu_field was applied. */
2637 {
2640 }
2642 /* If this was a bitfield, get the size from the old field.
2643 Also ensure the type can be placed into a bitfield. */
2645 {
2651 }
2660 /* If the size is now a constant, we can set it as the
2661 size of the field when we make it. Otherwise, we need
2662 to deal with it specially. */
2666 gnu_field
2667 = create_field_decl
2673 {
2682 bitsize_unit_node));
2684 }
2688 SET_DECL_ORIGINAL_FIELD
2699 }
2701 /* Now go through the entities again looking for Itypes that
2702 we have not elaborated but should (e.g., Etypes of fields
2703 that have Original_Components). */
2714 /* Now set the size, alignment and alias set of the new type to
2715 match that of the old one, doing any substitutions, as
2716 above. */
2742 SET_TYPE_ADA_SIZE
2747 /* Recompute the mode of this record type now that we know its
2748 actual size. */
2751 /* Fill in locations of fields. */
2753 }
2755 /* If we've made a new type, record it and make an XVS type to show
2756 what this is a subtype of. Some debuggers require the XVS
2757 type to be output first, so do it in that order. */
2759 {
2761 {
2772 integer_type_node,
2773 gnu_subtype_marker,
2777 }
2784 }
2786 /* Otherwise, go down all the components in the new type and
2787 make them equivalent to those in the base type. */
2788 else
2795 gnat_to_gnu_field_decl
2797 }
2802 /* If we are not defining this entity, and we have incomplete
2803 entities being processed above us, make a dummy type and
2804 fill it in later. */
2806 {
2810 gnu_type
2811 = build_pointer_type
2824 }
2826 /* ... fall through ... */
2833 {
2835 Entity_Id gnat_desig_full
2837 Incomplete_Or_Private_Kind))
2839 /* We want to know if we'll be seeing the freeze node for any
2840 incomplete type we may be pointing to. */
2841 bool in_main_unit
2857 {
2859 {
2863 }
2865 Incomplete_Or_Private_Kind))
2867 }
2872 /* If either the designated type or its full view is an
2873 unconstrained array subtype, replace it with the type it's a
2874 subtype of. This avoids problems with multiple copies of
2875 unconstrained array types. */
2884 /* If the designated type is a subtype of an incomplete record type,
2885 use the parent type to avoid order of elaboration issues. This
2886 can lose some code efficiency, but there is no alternative. */
2892 /* If we are pointing to an incomplete type whose completion is an
2893 unconstrained array, make a fat pointer type instead of a pointer
2894 to VOID. The two types in our fields will be pointers to VOID and
2895 will be replaced in update_pointer_to. Similarly, if the type
2896 itself is a dummy type or an unconstrained array. Also make
2897 a dummy TYPE_OBJECT_RECORD_TYPE in case we have any thin
2898 pointers to it. */
2914 && defer_incomplete_level
2918 {
2919 tree gnu_old
2923 tree fields;
2925 /* Show the dummy we get will be a fat pointer. */
2928 /* If the call above got something that has a pointer, that
2929 pointer is our type. This could have happened either
2930 because the type was elaborated or because somebody
2931 else executed the code below. */
2934 {
2940 fields
2942 create_field_decl
2947 ptr_void_type_node,
2950 /* Make sure we can place this into a register. */
2961 }
2962 }
2964 /* If we already know what the full type is, use it. */
2969 /* Get the type of the thing we are to point to and build a pointer
2970 to it. If it is a reference to an incomplete or private type with a
2971 full view that is a record, make a dummy type node and get the
2972 actual type later when we have verified it is safe. */
2978 {
2981 }
2983 /* Likewise if we are pointing to a record or array and we are to defer
2984 elaborating incomplete types. We do this since this access type
2985 may be the full view of some private type. Note that the
2986 unconstrained array case is handled above. */
2994 {
2997 }
2999 {
3000 gnu_type
3002 p_mode,
3005 }
3006 else
3009 /* It is possible that the above call to gnat_to_gnu_type resolved our
3010 type. If so, just return it. */
3012 {
3015 }
3017 /* If we have a GCC type for the designated type, possibly modify it
3018 if we are pointing only to constant objects and then make a pointer
3019 to it. Don't do this for unconstrained arrays. */
3021 {
3024 {
3025 gnu_desig_type
3026 = build_qualified_type
3030 /* Some extra processing is required if we are building a
3031 pointer to an incomplete type (in the GCC sense). We might
3032 have such a type if we just made a dummy, or directly out
3033 of the call to gnat_to_gnu_type above if we are processing
3034 an access type for a record component designating the
3035 record type itself. */
3037 {
3038 /* We must ensure that the pointer to variant we make will
3039 be processed by update_pointer_to when the initial type
3040 is completed. Pretend we made a dummy and let further
3041 processing act as usual. */
3044 /* We must ensure that update_pointer_to will not retrieve
3045 the dummy variant when building a properly qualified
3046 version of the complete type. We take advantage of the
3047 fact that get_qualified_type is requiring TYPE_NAMEs to
3048 match to influence build_qualified_type and then also
3049 update_pointer_to here. */
3052 }
3053 }
3055 gnu_type
3058 }
3060 /* If we are not defining this object and we made a dummy pointer,
3061 save our current definition, evaluate the actual type, and replace
3062 the tentative type we made with the actual one. If we are to defer
3063 actually looking up the actual type, make an entry in the
3064 deferred list. */
3067 {
3068 tree gnu_old_type
3074 gnu_type
3075 = build_pointer_type
3076 (TYPE_OBJECT_RECORD_TYPE
3086 /* Note that the call to gnat_to_gnu_type here might have
3087 updated gnu_old_type directly, in which case it is not a
3088 dummy type any more when we get into update_pointer_to.
3090 This may happen for instance when the designated type is a
3091 record type, because their elaboration starts with an
3092 initial node from make_dummy_type, which may yield the same
3093 node as the one we got.
3095 Besides, variants of this non-dummy type might have been
3096 created along the way. update_pointer_to is expected to
3097 properly take care of those situations. */
3100 else
3101 {
3109 }
3110 }
3111 }
3118 else
3119 /* The runtime representation is the equivalent type. */
3133 /* We treat this as identical to its base type; any constraint is
3134 meaningful only to the front end.
3136 The designated type must be elaborated as well, if it does
3137 not have its own freeze node. Designated (sub)types created
3138 for constrained components of records with discriminants are
3139 not frozen by the front end and thus not elaborated by gigi,
3140 because their use may appear before the base type is frozen,
3141 and because it is not clear that they are needed anywhere in
3142 Gigi. With the current model, there is no correct place where
3143 they could be elaborated. */
3150 {
3151 /* If we are not defining this entity, and we have incomplete
3152 entities being processed above us, make a dummy type and
3153 elaborate it later. */
3155 {
3158 tree gnu_ptr_type
3159 = build_pointer_type
3166 }
3169 Incomplete_Or_Private_Kind))
3170 ;
3171 else
3174 }
3179 /* Subprogram Entities
3181 The following access functions are defined for subprograms (functions
3182 or procedures):
3184 First_Formal The first formal parameter.
3185 Is_Imported Indicates that the subprogram has appeared in
3186 an INTERFACE or IMPORT pragma. For now we
3187 assume that the external language is C.
3188 Is_Inlined True if the subprogram is to be inlined.
3190 In addition for function subprograms we have:
3192 Etype Return type of the function.
3194 Each parameter is first checked by calling must_pass_by_ref on its
3195 type to determine if it is passed by reference. For parameters which
3196 are copied in, if they are Ada IN OUT or OUT parameters, their return
3197 value becomes part of a record which becomes the return type of the
3198 function (C function - note that this applies only to Ada procedures
3199 so there is no Ada return type). Additional code to store back the
3200 parameters will be generated on the caller side. This transformation
3201 is done here, not in the front-end.
3203 The intended result of the transformation can be seen from the
3204 equivalent source rewritings that follow:
3206 struct temp {int a,b};
3207 procedure P (A,B: IN OUT ...) is temp P (int A,B) {
3208 .. ..
3209 end P; return {A,B};
3210 }
3211 procedure call
3213 {
3214 temp t;
3215 P(X,Y); t = P(X,Y);
3216 X = t.a , Y = t.b;
3217 }
3219 For subprogram types we need to perform mainly the same conversions to
3220 GCC form that are needed for procedures and function declarations. The
3221 only difference is that at the end, we make a type declaration instead
3222 of a function declaration. */
3227 {
3228 /* The first GCC parameter declaration (a PARM_DECL node). The
3229 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3230 actually is the head of this parameter list. */
3232 /* The type returned by a function. If the subprogram is a procedure
3233 this type should be void_type_node. */
3235 /* List of fields in return type of procedure with copy in copy out
3236 parameters. */
3238 /* Non-null for subprograms containing parameters passed by copy in
3239 copy out (Ada IN OUT or OUT parameters not passed by reference),
3240 in which case it is the list of nodes used to specify the values of
3241 the in out/out parameters that are returned as a record upon
3242 procedure return. The TREE_PURPOSE of an element of this list is
3243 a field of the record and the TREE_VALUE is the PARM_DECL
3244 corresponding to that field. This list will be saved in the
3245 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3247 /* If an import pragma asks to map this subprogram to a GCC builtin,
3248 this is the builtin DECL node. */
3250 Entity_Id gnat_param;
3253 bool extern_flag
3265 /* A parameter may refer to this type, so defer completion
3266 of any incomplete types. */
3269 /* If the subprogram has an alias, it is probably inherited, so
3270 we can use the original one. If the original "subprogram"
3271 is actually an enumeration literal, it may be the first use
3272 of its type, so we must elaborate that type now. */
3274 {
3281 /* Elaborate any Itypes in the parameters of this entity. */
3289 }
3291 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3292 corresponding DECL node.
3294 We still want the parameter associations to take place because the
3295 proper generation of calls depends on it (a GNAT parameter without
3296 a corresponding GCC tree has a very specific meaning), so we don't
3297 just break here. */
3301 /* ??? What if we don't find the builtin node above ? warn ? err ?
3302 In the current state we neither warn nor err, and calls will just
3303 be handled as for regular subprograms. */
3308 /* If this function returns by reference, make the actual
3309 return type of this function the pointer and mark the decl. */
3311 {
3314 }
3316 /* If the Mechanism is By_Reference, ensure the return type uses
3317 the machine's by-reference mechanism, which may not the same
3318 as above (e.g., it might be by passing a fake parameter). */
3321 {
3324 }
3326 /* If we are supposed to return an unconstrained array,
3327 actually return a fat pointer and make a note of that. Return
3328 a pointer to an unconstrained record of variable size. */
3330 {
3333 }
3335 /* If the type requires a transient scope, the result is allocated
3336 on the secondary stack, so the result type of the function is
3337 just a pointer. */
3339 {
3342 }
3344 /* If the type is a padded type and the underlying type would not
3345 be passed by reference or this function has a foreign convention,
3346 return the underlying type. */
3354 /* If the return type is unconstrained, that means it must have a
3355 maximum size. We convert the function into a procedure and its
3356 caller will pass a pointer to an object of that maximum size as the
3357 first parameter when we call the function. */
3359 {
3361 gnu_param_list
3366 }
3368 /* If the return type has a size that overflows, we cannot have
3369 a function that returns that type. This usage doesn't make
3370 sense anyway, so give an error here. */
3373 {
3375 gnat_entity);
3381 }
3383 /* Look at all our parameters and get the type of
3384 each. While doing this, build a copy-out structure if
3385 we need one. */
3390 {
3400 /* Builtins are expanded inline and there is no real call sequence
3401 involved. so the type expected by the underlying expander is
3402 always the type of each argument "as is". */
3406 /* Otherwise, see if a Mechanism was supplied that forced this
3407 parameter to be passed one way or another. */
3411 ;
3419 {
3425 else
3427 }
3428 else
3431 /* If this is either a foreign function or if the
3432 underlying type won't be passed by reference, strip off
3433 possible padding type. */
3439 && (req_by_copy
3441 (TYPE_FIELDS
3445 /* If this is an IN parameter it is read-only, so make a variant
3446 of the type that is read-only.
3448 ??? However, if this is an unconstrained array, that type can
3449 be very complex. So skip it for now. Likewise for any other
3450 self-referential type. */
3454 gnu_param_type
3459 /* For foreign conventions, pass arrays as a pointer to the
3460 underlying type. First check for unconstrained array and get
3461 the underlying array. Then get the component type and build
3462 a pointer to it. */
3465 gnu_param_type
3470 gnu_param_type
3471 = build_pointer_type
3476 && !req_by_copy
3478 {
3479 /* Strip off any multi-dimensional entries, then strip
3480 off the last array to get the component type. */
3489 gnu_param_type
3495 }
3497 /* Fat pointers are passed as thin pointers for foreign
3498 conventions. */
3501 gnu_param_type
3505 /* If we must pass or were requested to pass by reference, do so.
3506 If we were requested to pass by copy, do so.
3507 Otherwise, for foreign conventions, pass all in out parameters
3508 or aggregates by reference. For COBOL and Fortran, pass
3509 all integer and FP types that way too. For Convention Ada,
3510 use the standard Ada default. */
3512 || (!req_by_copy
3522 /* For convention Ada, see if we pass by reference
3523 by default. */
3526 {
3529 }
3537 /* If this is an OUT parameter that isn't passed by reference
3538 and isn't a pointer or aggregate, we don't make a PARM_DECL
3539 for it. Instead, it will be a VAR_DECL created when we process
3540 the procedure. For the special parameter of Valued_Procedure,
3541 never pass it in.
3543 An exception is made to cover the RM-6.4.1 rule requiring "by
3544 copy" out parameters with discriminants or implicit initial
3545 values to be handled like in out parameters. These type are
3546 normally built as aggregates, and hence passed by reference,
3547 except for some packed arrays which end up encoded in special
3548 integer types.
3550 The exception we need to make is then for packed arrays of
3551 records with discriminants or implicit initial values. We have
3552 no light/easy way to check for the latter case, so we merely
3553 check for packed arrays of records. This may lead to useless
3554 copy-in operations, but in very rare cases only, as these would
3555 be exceptions in a set of already exceptional situations. */
3558 || (!by_descr_p
3566 else
3567 {
3568 gnu_param
3569 = create_param_decl
3571 by_ref_p || by_component_ptr_p
3585 /* If a parameter is a pointer, this function may modify
3586 memory through it and thus shouldn't be considered
3587 a pure function. Also, the memory may be modified
3588 between two calls, so they can't be CSE'ed. The latter
3589 case also handles by-ref parameters. */
3593 }
3596 {
3598 {
3603 }
3612 gnu_return_list);
3613 }
3614 }
3616 /* Do not compute record for out parameters if subprogram is
3617 stubbed since structures are incomplete for the back-end. */
3620 {
3621 /* If all types are not complete, defer emission of debug
3622 information for this record types. Otherwise, we risk emitting
3623 debug information for a dummy type contained in the fields
3624 for that record. */
3629 {
3631 defer_debug_level++;
3633 defer_debug_incomplete_list
3635 defer_debug_incomplete_list);
3636 }
3637 }
3639 /* If we have a CICO list but it has only one entry, we convert
3640 this function into a function that simply returns that one
3641 object. */
3645 #ifdef TARGET_DLLIMPORT_DECL_ATTRIBUTES
3647 {
3657 }
3658 #endif
3660 /* Both lists ware built in reverse. */
3664 gnu_type
3667 returns_by_ref,
3669 returns_by_target_ptr);
3671 /* A subprogram (something that doesn't return anything) shouldn't
3672 be considered Pure since there would be no reason for such a
3673 subprogram. Note that procedures with Out (or In Out) parameters
3674 have already been converted into a function with a return type. */
3678 gnu_type
3686 /* If we have a builtin decl for that function, check the signatures
3687 compatibilities. If the signatures are compatible, use the builtin
3688 decl. If they are not, we expect the checker predicate to have
3689 posted the appropriate errors, and just continue with what we have
3690 so far. */
3692 {
3696 {
3700 }
3701 }
3703 /* If there was no specified Interface_Name and the external and
3704 internal names of the subprogram are the same, only use the
3705 internal name to allow disambiguation of nested subprograms. */
3709 /* If we are defining the subprogram and it has an Address clause
3710 we must get the address expression from the saved GCC tree for the
3711 subprogram if it has a Freeze_Node. Otherwise, we elaborate
3712 the address expression here since the front-end has guaranteed
3713 in that case that the elaboration has no effects. If there is
3714 an Address clause and we are not defining the object, just
3715 make it a constant. */
3717 {
3721 gnu_address
3732 gnu_decl
3737 }
3743 gnat_entity);
3744 else
3745 {
3750 gnat_entity);
3753 }
3754 }
3765 /* If this type does not have a full view in the unit we are
3766 compiling, then just get the type from its Etype. */
3768 {
3769 /* If this is an incomplete type with no full view, it must
3770 be a Taft Amendement type, so just return a dummy type. */
3777 else
3778 {
3782 }
3785 }
3787 /* Otherwise, if we are not defining the type now, get the
3788 type from the full view. But always get the type from the full
3789 view for define on use types, since otherwise we won't see them! */
3796 {
3801 }
3803 /* For incomplete types, make a dummy type entry which will be
3804 replaced later. */
3807 /* Save this type as the full declaration's type so we can do any needed
3808 updates when we see it. */
3815 /* Simple class_wide types are always viewed as their root_type
3816 by Gigi unless an Equivalent_Type is specified. */
3820 else
3832 else
3844 /* Nothing at all to do here, so just return an ERROR_MARK and claim
3845 we've already saved it, so we don't try to. */
3852 }
3854 /* If we had a case where we evaluated another type and it might have
3855 defined this one, handle it here. */
3857 {
3860 }
3862 /* If we are processing a type and there is either no decl for it or
3863 we just made one, do some common processing for the type, such as
3864 handling alignment and possible padding. */
3867 {
3875 /* ??? Don't set the size for a String_Literal since it is either
3876 confirming or we don't handle it properly (if the low bound is
3877 non-constant). */
3883 /* If a size was specified, see if we can make a new type of that size
3884 by rearranging the type, for example from a fat to a thin pointer. */
3886 {
3887 gnu_type
3894 }
3896 /* If the alignment hasn't already been processed and this is
3897 not an unconstrained array, see if an alignment is specified.
3898 If not, we pick a default alignment for atomic objects. */
3900 ;
3914 /* See if we need to pad the type. If we did, and made a record,
3915 the name of the new type may be changed. So get it back for
3916 us when we make the new TYPE_DECL below. */
3921 {
3925 }
3929 /* If we are at global level, GCC will have applied variable_size to
3930 the type, but that won't have done anything. So, if it's not
3931 a constant or self-referential, call elaborate_expression_1 to
3932 make a variable for the size rather than calculating it each time.
3933 Handle both the RM size and the actual size. */
3938 {
3942 {
3949 }
3950 else
3951 {
3958 /* ??? For now, store the size as a multiple of the alignment
3959 in bytes so that we can see the alignment from the tree. */
3961 = build_binary_op
3963 elaborate_expression_1
3974 SET_TYPE_ADA_SIZE
3977 gnat_entity,
3981 }
3982 }
3984 /* If this is a record type or subtype, call elaborate_expression_1 on
3985 any field position. Do this for both global and local types.
3986 Skip any fields that we haven't made trees for to avoid problems with
3987 class wide types. */
3992 {
3995 /* ??? Unfortunately, GCC needs to be able to prove the
3996 alignment of this offset and if it's a variable, it can't.
3997 In GCC 3.4, we'll use DECL_OFFSET_ALIGN in some way, but
3998 right now, we have to put in an explicit multiply and
3999 divide by that value. */
4002 = build_binary_op
4004 elaborate_expression_1
4013 }
4017 | (TYPE_QUAL_VOLATILE
4030 else
4032 }
4035 {
4038 /* Back-annotate the Alignment of the type if not already in the
4039 tree. Likewise for sizes. */
4045 {
4046 /* If the size is self-referential, we annotate the maximum
4047 value of that size. */
4056 {
4057 /* In this mode the tag and the parent components are not
4058 generated by the front-end, so the sizes must be adjusted
4059 explicitly now. */
4065 {
4066 size_offset
4070 }
4071 else
4079 }
4080 }
4084 }
4093 /* If we haven't already, associate the ..._DECL node that we just made with
4094 the input GNAT entity node. */
4098 /* If this is an enumeral or floating-point type, we were not able to set
4099 the bounds since they refer to the type. These bounds are always static.
4101 For enumeration types, also write debugging information and declare the
4102 enumeration literal table, if needed. */
4106 {
4109 /* If this is a padded type, we need to use the underlying type. */
4114 /* If this is a floating point type and we haven't set a floating
4115 point type yet, use this in the evaluation of the bounds. */
4125 {
4128 /* Since this has both a typedef and a tag, avoid outputting
4129 the name twice. */
4132 }
4133 }
4135 /* If we deferred processing of incomplete types, re-enable it. If there
4136 were no other disables and we have some to process, do so. */
4138 {
4144 {
4151 }
4152 }
4154 /* If we are not defining this type, see if it's in the incomplete list.
4155 If so, handle that list entry now. */
4157 {
4162 {
4166 }
4167 }
4169 /* If there are no incomplete types and we have deferred emission
4170 of debug information, check whether we have finished defining
4171 all nested records.
4172 If so, handle the list now. */
4175 defer_debug_level--;
4178 && !defer_incomplete_level
4180 {
4186 {
4189 }
4192 }
4195 force_global--;
4204 }
4206 /* Similar, but if the returned value is a COMPONENT_REF, return the
4207 FIELD_DECL. */
4209 tree
4211 {
4218 }
4219 \f
4220 /* Given GNAT_ENTITY, elaborate all expressions that are required to
4221 be elaborated at the point of its definition, but do nothing else. */
4223 void
4225 {
4227 {
4234 {
4238 /* ??? Tests for avoiding static constraint error expression
4239 is needed until the front stops generating bogus conversions
4240 on bounds of real types. */
4249 }
4252 {
4256 /* If this is a record extension, go a level further to find the
4257 record definition. */
4260 }
4270 {
4271 Node_Id gnat_discriminant_expr;
4272 Entity_Id gnat_field;
4275 gnat_discriminant_expr
4280 /* ??? For now, ignore access discriminants. */
4283 gnat_entity,
4285 }
4288 }
4289 }
4290 \f
4291 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
4292 any entities on its entity chain similarly. */
4294 void
4296 {
4297 Entity_Id gnat_sub_entity;
4300 /* If this has an entity list, process all in the list. */
4317 /* Now clear this if it has been defined, but only do so if it isn't
4318 a subprogram or parameter. We could refine this, but it isn't
4319 worth it. If this is statically allocated, it is supposed to
4320 hang around out of cope. */
4323 {
4326 }
4327 }
4328 \f
4329 /* Set the alias set of GNU_NEW_TYPE to be that of GNU_OLD_TYPE. If this
4330 is a multi-dimensional array type, do this recursively. */
4332 static void
4334 {
4335 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
4336 of a one-dimensional array, since the padding has the same alias set
4337 as the field type, but if it's a multi-dimensional array, we need to
4338 see the inner types. */
4344 /* We need to be careful here in case GNU_OLD_TYPE is an unconstrained
4345 array. In that case, it doesn't have the same shape as GNU_NEW_TYPE,
4346 so we need to go down to what does. */
4348 gnu_old_type
4358 }
4359 \f
4360 /* Return a TREE_LIST describing the substitutions needed to reflect
4361 discriminant substitutions from GNAT_SUBTYPE to GNAT_TYPE and add
4362 them to GNU_LIST. If GNAT_TYPE is not specified, use the base type
4363 of GNAT_SUBTYPE. The substitutions can be in any order. TREE_PURPOSE
4364 gives the tree for the discriminant and TREE_VALUES is the replacement
4365 value. They are in the form of operands to substitute_in_expr.
4366 DEFINITION is as in gnat_to_gnu_entity. */
4368 static tree
4371 {
4372 Entity_Id gnat_discrim;
4373 Node_Id gnat_value;
4384 /* Ignore access discriminants. */
4387 elaborate_expression
4391 gnu_list);
4394 }
4395 \f
4396 /* For the following two functions: for each GNAT entity, the GCC
4397 tree node used as a dummy for that entity, if any. */
4401 /* Initialize the above table. */
4403 void
4405 {
4406 Node_Id gnat_node;
4414 }
4416 /* Make a dummy type corresponding to GNAT_TYPE. */
4418 tree
4420 {
4421 Entity_Id gnat_underlying;
4422 tree gnu_type;
4424 /* Find a full type for GNAT_TYPE, taking into account any class wide
4425 types. */
4435 ;
4437 /* If it there already a dummy type, use that one. Else make one. */
4441 /* If this is a record, make this a RECORD_TYPE or UNION_TYPE; else make
4442 it a VOID_TYPE. */
4444 {
4447 }
4450 else
4461 }
4462 \f
4463 /* Return true if the size represented by GNU_SIZE can be handled by an
4464 allocation. If STATIC_P is true, consider only what can be done with a
4465 static allocation. */
4467 static bool
4469 {
4470 HOST_WIDE_INT our_size;
4472 /* If this is not a static allocation, the only case we want to forbid
4473 is an overflowing size. That will be converted into a raise a
4474 Storage_Error. */
4479 /* Otherwise, we need to deal with both variable sizes and constant
4480 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
4481 since assemblers may not like very large sizes. */
4487 }
4488 \f
4489 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
4491 static void
4493 {
4494 Node_Id gnat_temp;
4499 {
4509 {
4511 (gnat_to_gnu
4518 (gnat_to_gnu
4519 (Expression
4522 }
4525 {
4552 }
4559 /* If we have an argument specified together with an attribute name,
4560 make it a single TREE_VALUE entry in a list of arguments, as GCC
4561 expects it. */
4564 else
4567 attr->error_point
4571 }
4572 }
4573 \f
4574 /* Get the unpadded version of a GNAT type. */
4576 tree
4578 {
4585 }
4586 \f
4587 /* Called when we need to protect a variable object using a save_expr. */
4589 tree
4591 {
4598 {
4606 }
4607 else
4609 }
4610 \f
4611 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
4612 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
4613 return the GCC tree to use for that expression. GNU_NAME is the
4614 qualification to use if an external name is appropriate and DEFINITION is
4615 nonzero if this is a definition of GNAT_ENTITY. If NEED_VALUE is nonzero,
4616 we need a result. Otherwise, we are just elaborating this for
4617 side-effects. If NEED_DEBUG is nonzero we need the symbol for debugging
4618 purposes even if it isn't needed for code generation. */
4620 static tree
4624 {
4625 tree gnu_expr;
4627 /* If we already elaborated this expression (e.g., it was involved
4628 in the definition of a private type), use the old value. */
4632 /* If we don't need a value and this is static or a discriment, we
4633 don't need to do anything. */
4640 /* Otherwise, convert this tree to its GCC equivalent. */
4641 gnu_expr
4645 /* Save the expression in case we try to elaborate this entity again. Since
4646 this is not a DECL, don't check it. Don't save if it's a discriminant. */
4651 }
4653 /* Similar, but take a GNU expression. */
4655 static tree
4659 {
4661 /* Strip any conversions to see if the expression is a readonly variable.
4662 ??? This really should remain readonly, but we have to think about
4663 the typing of the tree here. */
4668 /* In most cases, we won't see a naked FIELD_DECL here because a
4669 discriminant reference will have been replaced with a COMPONENT_REF
4670 when the type is being elaborated. However, there are some cases
4671 involving child types where we will. So convert it to a COMPONENT_REF
4672 here. We have to hope it will be at the highest level of the
4673 expression in these cases. */
4679 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
4680 that is a constant, make a variable that is initialized to contain the
4681 bound when the package containing the definition is elaborated. If
4682 this entity is defined at top level and a bound or discriminant value
4683 isn't a constant or a reference to a discriminant, replace the bound
4684 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
4685 rely here on the fact that an expression cannot contain both the
4686 discriminant and some other variable. */
4693 /* If this is a static expression or contains a discriminant, we don't
4694 need the variable for debugging (and can't elaborate anyway if a
4695 discriminant). */
4701 /* Now create the variable if we need it. */
4703 gnu_decl
4708 gnat_entity);
4710 /* We only need to use this variable if we are in global context since GCC
4711 can do the right thing in the local case. */
4716 else
4718 }
4719 \f
4720 /* Create a record type that contains a field of TYPE with a starting bit
4721 position so that it is aligned to ALIGN bits and is SIZE bytes long. */
4723 tree
4725 {
4730 place));
4739 /* The bit position is obtained by "and"ing the alignment minus 1
4740 with the two's complement of the address and multiplying
4741 by the number of bits per unit. Do all this in sizetype. */
4746 size_addr_place),
4749 bitsize_unit_node);
4751 /* Create the field, with -1 as the 'addressable' indication to avoid the
4752 creation of a bitfield. We don't need one, it would have damaging
4753 consequences on the alignment computation, and create_field_decl would
4754 make one without this special argument, for instance because of the
4755 complex position expression. */
4764 bitsize_unit_node),
4770 }
4771 \f
4772 /* TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE, with BLKmode that's
4773 being used as the field type of a packed record. See if we can rewrite it
4774 as a record that has a non-BLKmode type, which we can pack tighter. If so,
4775 return the new type. If not, return the original type. */
4777 static tree
4779 {
4782 tree old_field;
4784 /* Copy the name and flags from the old type to that of the new and set
4785 the alignment to try for an integral type. For QUAL_UNION_TYPE,
4786 also copy the size. */
4795 {
4798 }
4804 /* Now copy the fields, keeping the position and size. */
4807 {
4809 tree new_field;
4825 SET_DECL_ORIGINAL_FIELD
4834 }
4839 }
4840 \f
4841 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
4842 if needed. We have already verified that SIZE and TYPE are large enough.
4844 GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
4845 to issue a warning.
4847 IS_USER_TYPE is true if we must be sure we complete the original type.
4849 DEFINITION is true if this type is being defined.
4851 SAME_RM_SIZE is true if the RM_Size of the resulting type is to be
4852 set to its TYPE_SIZE; otherwise, it's set to the RM_Size of the original
4853 type. */
4855 tree
4859 {
4861 tree record;
4862 tree field;
4864 /* If TYPE is a padded type, see if it agrees with any size and alignment
4865 we were given. If so, return the original type. Otherwise, strip
4866 off the padding, since we will either be returning the inner type
4867 or repadding it. If no size or alignment is specified, use that of
4868 the original padded type. */
4871 {
4888 }
4890 /* If the size is either not being changed or is being made smaller (which
4891 is not done here (and is only valid for bitfields anyway), show the size
4892 isn't changing. Likewise, clear the alignment if it isn't being
4893 changed. Then return if we aren't doing anything. */
4907 /* We used to modify the record in place in some cases, but that could
4908 generate incorrect debugging information. So make a new record
4909 type and name. */
4915 /* If we were making a type, complete the original type and give it a
4916 name. */
4923 gnat_entity);
4925 /* If we are changing the alignment and the input type is a record with
4926 BLKmode and a small constant size, try to make a form that has an
4927 integral mode. That might allow this record to have an integral mode,
4928 which will be much more efficient. There is no point in doing this if a
4929 size is specified unless it is also smaller than the biggest alignment
4930 and it is incorrect to do this if the size of the original type is not a
4931 multiple of the alignment. */
4937 && (!size
4959 /* Keep the RM_Size of the padded record as that of the old record
4960 if requested. */
4963 /* Unless debugging information isn't being written for the input type,
4964 write a record that shows what we are a subtype of and also make a
4965 variable that indicates our size, if variable. */
4969 {
4990 }
4997 /* If the size was widened explicitly, maybe give a warning. */
5003 {
5016 /* Generate message only for entities that come from source, since
5017 if we have an entity created by expansion, the message will be
5018 generated for some other corresponding source entity. */
5021 gnat_entity,
5028 }
5031 }
5032 \f
5033 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
5034 the value passed against the list of choices. */
5036 tree
5038 {
5039 Node_Id choice;
5040 Node_Id gnat_temp;
5045 {
5047 {
5052 /* There's no good type to use here, so we might as well use
5053 integer_type_node. */
5054 this_test
5068 this_test
5078 /* This represents either a subtype range, an enumeration
5079 literal, or a constant Ekind says which. If an enumeration
5080 literal or constant, fall through to the next case. */
5083 {
5089 this_test
5096 }
5097 /* ... fall through ... */
5102 single);
5111 }
5115 }
5118 }
5119 \f
5120 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
5121 placed in GNU_RECORD_TYPE.
5123 PACKED is 1 if the enclosing record is packed and -1 if the enclosing
5124 record has a Component_Alignment of Storage_Unit.
5126 DEFINITION is true if this field is for a record being defined. */
5128 static tree
5131 {
5136 tree gnu_field;
5137 bool needs_strict_alignment
5141 /* If this field requires strict alignment or contains an item of
5142 variable sized, pretend it isn't packed. */
5146 /* For packed records, this is one of the few occasions on which we use
5147 the official RM size for discrete or fixed-point components, instead
5148 of the normal GNAT size stored in Esize. See description in Einfo:
5149 "Handling of Type'Size Values" for further details. */
5159 /* If we are packing this record, have a specified size that's smaller than
5160 that of the field type, or a position is specified, and the field type is
5161 also a record that's BLKmode and with a small constant size, see if we
5162 can get a better form of the type that allows more packing. If we can,
5163 show a size was specified for it if there wasn't one so we know to make
5164 this a bitfield and avoid making things wider. */
5170 || (gnu_size
5173 {
5174 /* See what the alternate type and size would be. */
5177 /* Compute whether we should avoid the substitution. */
5179 /* There is no point substituting if there is no change. */
5181 ||
5182 /* The size of an aliased field must be an exact multiple of the
5183 type's alignment, which the substitution might increase. Reject
5184 substitutions that would so invalidate a component clause when the
5185 specified position is byte aligned, as the change would have no
5186 real benefit from the packing standpoint anyway. */
5191 );
5193 /* Substitute unless told otherwise. */
5195 {
5200 }
5201 }
5203 /* If we are packing the record and the field is BLKmode, round the
5204 size up to a byte boundary. */
5209 {
5214 /* Ensure the position does not overlap with the parent subtype,
5215 if there is one. */
5217 {
5218 tree gnu_parent
5224 {
5225 post_error_ne_tree
5229 }
5230 }
5232 /* If this field needs strict alignment, ensure the record is
5233 sufficiently aligned and that that position and size are
5234 consistent with the alignment. */
5236 {
5243 /* If Atomic, the size must match exactly that of the field. */
5246 {
5247 post_error_ne_tree
5253 }
5255 /* If Aliased, the size must match exactly the rounded size. We
5256 used to be more accommodating here and accept greater sizes, but
5257 fully supporting this case on big-endian platforms would require
5258 switching to a more involved layout for the field. */
5260 && gnu_size
5262 {
5263 post_error_ne_tree
5266 gnu_rounded_size);
5268 }
5273 {
5275 post_error_ne_num
5281 post_error_ne_num
5287 post_error_ne_num
5291 else
5295 }
5296 }
5300 }
5302 /* If the record has rep clauses and this is the tag field, make a rep
5303 clause for it as well. */
5306 {
5309 }
5311 /* We need to make the size the maximum for the type if it is
5312 self-referential and an unconstrained type. In that case, we can't
5313 pack the field since we can't make a copy to align it. */
5315 && !gnu_size
5318 {
5321 }
5323 /* If no size is specified (or if there was an error), don't specify a
5324 position. */
5327 else
5328 {
5329 /* If the field's type is justified modular, we would need to remove
5330 the wrapper to (better) meet the layout requirements. However we
5331 can do so only if the field is not aliased to preserve the unique
5332 layout and if the prescribed size is not greater than that of the
5333 packed array to preserve the justification. */
5341 gnu_field_type
5346 }
5351 /* Now create the decl for the field. */
5363 }
5364 \f
5365 /* Return true if TYPE is a type with variable size, a padding type with a
5366 field of variable size or is a record that has a field such a field. */
5368 static bool
5370 {
5371 tree field;
5373 /* We need not be concerned about this at all if we don't have
5374 strict alignment. */
5392 }
5393 \f
5394 /* Return a GCC tree for a record type given a GNAT Component_List and a chain
5395 of GCC trees for fields that are in the record and have already been
5396 processed. When called from gnat_to_gnu_entity during the processing of a
5397 record type definition, the GCC nodes for the discriminants will be on
5398 the chain. The other calls to this function are recursive calls from
5399 itself for the Component_List of a variant and the chain is empty.
5401 PACKED is 1 if this is for a record with "pragma pack" and -1 is this is
5402 for a record type with "pragma component_alignment (storage_unit)".
5404 DEFINITION is true if we are defining this record.
5406 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
5407 with a rep clause is to be added. If it is nonzero, that is all that
5408 should be done with such fields.
5410 CANCEL_ALIGNMENT, if true, means the alignment should be zeroed before
5411 laying out the record. This means the alignment only serves to force fields
5412 to be bitfields, but not require the record to be that aligned. This is
5413 used for variants.
5415 ALL_REP, if true, means a rep clause was found for all the fields. This
5416 simplifies the logic since we know we're not in the mixed case.
5418 DEFER_DEBUG, if true, means that the debugging routines should not be
5419 called when finishing constructing the record type.
5421 The processing of the component list fills in the chain with all of the
5422 fields of the record and then the record type is finished. */
5424 static void
5429 {
5430 Node_Id component_decl;
5431 Entity_Id gnat_field;
5432 Node_Id variant_part;
5433 Node_Id variant;
5439 /* For each variable within each component declaration create a GCC field
5440 and add it to the list, skipping any pragmas in the list. */
5446 {
5451 else
5452 {
5456 /* If this is the _Tag field, put it before any discriminants,
5457 instead of after them as is the case for all other fields.
5458 Ignore field of void type if only annotating. */
5461 else
5462 {
5465 }
5466 }
5469 }
5471 /* At the end of the component list there may be a variant part. */
5474 /* If this is an unchecked union, each variant must have exactly one
5475 component, each of which becomes one component of this union. */
5482 {
5483 component_decl
5487 definition);
5491 }
5493 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
5494 mutually exclusive and should go in the same memory. To do this we need
5495 to treat each variant as a record whose elements are created from the
5496 component list for the variant. So here we create the records from the
5497 lists for the variants and put them all into the QUAL_UNION_TYPE. */
5499 {
5501 Node_Id variant;
5503 tree gnu_union_field;
5506 tree gnu_var_name
5507 = concat_id_with_name
5521 {
5523 tree gnu_inner_name;
5524 tree gnu_qual;
5532 /* Set the alignment of the inner type in case we need to make
5533 inner objects into bitfields, but then clear it out
5534 so the record actually gets only the alignment required. */
5538 /* Similarly, if the outer record has a size specified and all fields
5539 have record rep clauses, we can propagate the size into the
5540 variant part. */
5542 {
5546 }
5559 (all_rep_and_size
5561 (all_rep_and_size
5569 }
5571 /* We use to delete the empty variants from the end. However,
5572 we no longer do that because we need them to generate complete
5573 debugging information for the variant record. Otherwise,
5574 the union type definition will be missing the fields associated
5575 to these empty variants. */
5577 /* Only make the QUAL_UNION_TYPE if there are any non-empty variants. */
5579 {
5581 {
5585 }
5590 gnu_union_field
5592 packed,
5599 }
5600 }
5602 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
5603 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do this
5604 in a separate pass since we want to handle the discriminants but can't
5605 play with them until we've used them in debugging data above.
5607 ??? Note: if we then reorder them, debugging information will be wrong,
5608 but there's nothing that can be done about this at the moment. */
5611 {
5613 {
5618 else
5624 }
5625 else
5626 {
5629 }
5630 }
5632 /* If we have any items in our rep'ed field list, it is not the case that all
5633 the fields in the record have rep clauses, and P_REP_LIST is nonzero,
5634 set it and ignore the items. Otherwise, sort the fields by bit position
5635 and put them into their own record if we have any fields without
5636 rep clauses. */
5640 {
5641 tree gnu_rep_type
5647 /* Set/abuse DECL_FCONTEXT to increasing integers so we have a
5648 stable sort. */
5651 {
5654 }
5658 /* Put the fields in the list in order of increasing position, which
5659 means we start from the end. */
5662 {
5667 }
5670 {
5676 }
5677 else
5678 {
5681 }
5682 }
5689 }
5690 \f
5691 /* Called via qsort from the above. Returns -1, 1, depending on the
5692 bit positions and ordinals of the two fields. */
5694 static int
5696 {
5701 return
5706 else
5708 }
5709 \f
5710 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
5711 placed into an Esize, Component_Bit_Offset, or Component_Size value
5712 in the GNAT tree. */
5714 static Uint
5716 {
5718 TCode tcode;
5723 /* See if we've already saved the value for this node. */
5727 /* If we do not return inside this switch, TCODE will be set to the
5728 code to use for a Create_Node operand and LEN (set above) will be
5729 the number of recursive calls for us to make. */
5732 {
5737 /* This may have come from a conversion from some smaller type,
5738 so ensure this is in bitsizetype. */
5741 /* For negative values, use NEGATE_EXPR of the supplied value. */
5743 {
5744 /* The ridiculous code below is to handle the case of the largest
5745 negative integer. */
5748 tree temp;
5751 {
5752 negative_size
5755 bitsize_one_node));
5757 }
5764 }
5771 /* This peculiar test is to make sure that the size fits in an int
5772 on machines where HOST_WIDE_INT is not "int". */
5775 else
5779 /* The only case we handle here is a simple discriminant reference. */
5787 else
5793 /* Now just list the operations we handle. */
5824 }
5826 /* Now get each of the operands that's relevant for this code. If any
5827 cannot be expressed as a repinfo node, say we can't. */
5832 {
5836 }
5841 }
5843 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding
5844 GCC type, set Component_Bit_Offset and Esize to the position and size
5845 used by Gigi. */
5847 static void
5849 {
5850 tree gnu_list;
5851 tree gnu_entry;
5852 Entity_Id gnat_field;
5854 /* We operate by first making a list of all fields and their positions
5855 (we can get the sizes easily at any time) by a recursive call
5856 and then update all the sizes into the tree. */
5859 BIGGEST_ALIGNMENT);
5866 {
5870 gnu_list);
5873 {
5875 {
5876 /* In this mode the tag and parent components have not been
5877 generated, so we add the appropriate offset to each
5878 component. For a component appearing in the current
5879 extension, the offset is the size of the parent. */
5882 parent_offset
5884 bitsizetype);
5885 else
5887 }
5889 Set_Component_Bit_Offset
5891 annotate_value
5896 parent_offset)));
5900 }
5904 {
5905 /* If there is no gnu_entry, this is an inherited component whose
5906 position is the same as in the parent type. */
5907 Set_Component_Bit_Offset
5912 }
5913 }
5914 }
5916 /* Scan all fields in GNU_TYPE and build entries where TREE_PURPOSE is the
5917 FIELD_DECL and TREE_VALUE a TREE_LIST with TREE_PURPOSE being the byte
5918 position and TREE_VALUE being a TREE_LIST with TREE_PURPOSE the value to be
5919 placed into DECL_OFFSET_ALIGN and TREE_VALUE the bit position. GNU_POS is
5920 to be added to the position, GNU_BITPOS to the bit position, OFFSET_ALIGN is
5921 the present value of DECL_OFFSET_ALIGN and GNU_LIST is a list of the entries
5922 so far. */
5924 static tree
5927 {
5928 tree gnu_field;
5933 {
5938 unsigned int our_offset_align
5941 gnu_result
5946 NULL_TREE),
5947 gnu_result);
5950 gnu_result
5953 our_offset_align);
5954 }
5957 }
5958 \f
5959 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
5960 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
5961 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
5962 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
5963 for the size of a field. COMPONENT_P is true if we are being called
5964 to process the Component_Size of GNAT_OBJECT. This is used for error
5965 message handling and to indicate to use the object size of GNU_TYPE.
5966 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
5967 it means that a size of zero should be treated as an unspecified size. */
5969 static tree
5972 {
5973 Node_Id gnat_error_node;
5974 tree type_size
5976 tree size;
5978 /* Find the node to use for errors. */
5985 else
5988 /* Return 0 if no size was specified, either because Esize was not Present or
5989 the specified size was zero. */
5993 /* Get the size as a tree. Give an error if a size was specified, but cannot
5994 be represented as in sizetype. */
5997 {
6002 }
6004 /* Ignore a negative size since that corresponds to our back-annotation.
6005 Also ignore a zero size unless a size clause exists. */
6009 /* The size of objects is always a multiple of a byte. */
6012 {
6016 else
6020 }
6022 /* If this is an integral type or a packed array type, the front-end has
6023 verified the size, so we need not do it here (which would entail
6024 checking against the bounds). However, if this is an aliased object, it
6025 may not be smaller than the type of the object. */
6030 /* If the object is a record that contains a template, add the size of
6031 the template to the specified size. */
6036 /* Modify the size of the type to be that of the maximum size if it has a
6037 discriminant or the size of a thin pointer if this is a fat pointer. */
6043 /* If this is an access type, the minimum size is that given by the smallest
6044 integral mode that's valid for pointers. */
6046 {
6052 ;
6055 }
6057 /* If the size of the object is a constant, the new size must not be
6058 smaller. */
6062 {
6064 post_error_ne_tree
6067 else
6074 post_error_ne_tree_2
6084 }
6087 }
6088 \f
6089 /* Similarly, but both validate and process a value of RM_Size. This
6090 routine is only called for types. */
6092 static void
6094 {
6095 /* Only give an error if a Value_Size clause was explicitly given.
6096 Otherwise, we'd be duplicating an error on the Size clause. */
6097 Node_Id gnat_attr_node
6100 tree size;
6102 /* Get the size as a tree. Do nothing if none was specified, either
6103 because RM_Size was not Present or if the specified size was zero.
6104 Give an error if a size was specified, but cannot be represented as
6105 in sizetype. */
6111 {
6114 gnat_entity);
6117 }
6119 /* Ignore a negative size since that corresponds to our back-annotation.
6120 Also ignore a zero size unless a size clause exists, a Value_Size
6121 clause exists, or this is an integer type, in which case the
6122 front end will have always set it. */
6129 /* If the old size is self-referential, get the maximum size. */
6133 /* If the size of the object is a constant, the new size must not be
6134 smaller (the front end checks this for scalar types). */
6139 {
6141 post_error_ne_tree
6146 }
6148 /* Otherwise, set the RM_Size. */
6159 }
6160 \f
6161 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
6162 If TYPE is the best type, return it. Otherwise, make a new type. We
6163 only support new integral and pointer types. BIASED_P is nonzero if
6164 we are making a biased type. */
6166 static tree
6168 {
6169 tree new_type;
6173 /* If size indicates an error, just return TYPE to avoid propagating the
6174 error. Likewise if it's too large to represent. */
6180 {
6183 /* Only do something if the type is not already the proper size and is
6184 not a packed array type. */
6196 new_type
6208 /* Do something if this is a fat pointer, in which case we
6209 may need to return the thin pointer. */
6211 return
6212 build_pointer_type
6217 /* Only do something if this is a thin pointer, in which case we
6218 may need to return the fat pointer. */
6220 return
6227 }
6230 }
6231 \f
6232 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
6233 a type or object whose present alignment is ALIGN. If this alignment is
6234 valid, return it. Otherwise, give an error and return ALIGN. */
6236 static unsigned int
6238 {
6242 #ifndef MAX_OFILE_ALIGNMENT
6243 #define MAX_OFILE_ALIGNMENT BIGGEST_ALIGNMENT
6244 #endif
6249 /* Don't worry about checking alignment if alignment was not specified
6250 by the source program and we already posted an error for this entity. */
6255 /* Within GCC, an alignment is an integer, so we must make sure a
6256 value is specified that fits in that range. Also, alignments of
6257 more than MAX_OFILE_ALIGNMENT can't be supported. */
6271 else
6275 }
6276 \f
6277 /* Verify that OBJECT, a type or decl, is something we can implement
6278 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
6279 if we require atomic components. */
6281 static void
6283 {
6285 Node_Id gnat_node;
6288 tree size;
6290 /* There are three case of what OBJECT can be. It can be a type, in which
6291 case we take the size, alignment and mode from the type. It can be a
6292 declaration that was indirect, in which case the relevant values are
6293 that of the type being pointed to, or it can be a normal declaration,
6294 in which case the values are of the decl. The code below assumes that
6295 OBJECT is either a type or a decl. */
6297 {
6301 }
6303 {
6307 }
6308 else
6309 {
6313 }
6315 /* Consider all floating-point types atomic and any types that that are
6316 represented by integers no wider than a machine word. */
6323 /* For the moment, also allow anything that has an alignment equal
6324 to its size and which is smaller than a word. */
6332 {
6340 }
6345 else
6348 }
6349 \f
6350 /* Check if FTYPE1 and FTYPE2, two potentially different function type nodes,
6351 have compatible signatures so that a call using one type may be safely
6352 issued if the actual target function type is the other. Return 1 if it is
6353 the case, 0 otherwise, and post errors on the incompatibilities.
6355 This is used when an Ada subprogram is mapped onto a GCC builtin, to ensure
6356 that calls to the subprogram will have arguments suitable for the later
6357 underlying builtin expansion. */
6359 static int
6361 {
6362 /* As of now, we only perform very trivial tests and consider it's the
6363 programmer's responsibility to ensure the type correctness in the Ada
6364 declaration, as in the regular Import cases.
6366 Mismatches typically result in either error messages from the builtin
6367 expander, internal compiler errors, or in a real call sequence. This
6368 should be refined to issue diagnostics helping error detection and
6369 correction. */
6371 /* Almost fake test, ensuring a use of each argument. */
6376 }
6377 \f
6378 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new type
6379 with all size expressions that contain F updated by replacing F with R.
6380 This is identical to GCC's substitute_in_type except that it knows about
6381 TYPE_INDEX_TYPE. If F is NULL_TREE, always make a new RECORD_TYPE, even if
6382 nothing has changed. */
6384 tree
6386 {
6388 tree tem;
6391 {
6398 {
6407 SET_TYPE_INDEX_TYPE
6410 }
6417 {
6431 }
6445 /* Don't know how to do these yet. */
6449 {
6463 /* If we had bounded the sizes of T by a constant, bound the sizes of
6464 NEW by the same constant. */
6474 }
6479 {
6480 tree field;
6481 bool changed_field
6488 /* Start out with no fields, make new fields, and chain them
6489 in. If we haven't actually changed the type of any field,
6490 discard everything we've done and return the old type. */
6496 {
6507 /* If this is an internal field and the type of this field is
6508 a UNION_TYPE or RECORD_TYPE with no elements, ignore it. If
6509 the type just has one element, treat that as the field.
6510 But don't do this if we are processing a QUAL_UNION_TYPE. */
6515 {
6520 {
6521 tree next_new_field
6524 /* Make sure omitting the union doesn't change
6525 the layout. */
6528 }
6529 }
6536 /* If the size of the old field was set at a constant,
6537 propagate the size in case the type's size was variable.
6538 (This occurs in the case of a variant or discriminated
6539 record with a default size used as a field of another
6540 record.) */
6549 {
6555 /* Do the substitution inside the qualifier and if we find
6556 that this field will not be present, omit it. */
6561 }
6565 else
6570 /* If this is a qualified type and this field will always be
6571 present, we are done. */
6575 }
6577 /* If this used to be a qualified union type, but we now know what
6578 field will be present, make this a normal union. */
6589 /* If the size was originally a constant use it. */
6592 {
6596 }
6599 }
6603 }
6604 }
6605 \f
6606 /* Return the "RM size" of GNU_TYPE. This is the actual number of bits
6607 needed to represent the object. */
6609 tree
6611 {
6612 /* For integer types, this is the precision. For record types, we store
6613 the size explicitly. For other types, this is just the size. */
6619 /* Return the rm_size of the actual data plus the size of the template. */
6620 return
6630 else
6632 }
6633 \f
6634 /* Return an identifier representing the external name to be used for
6635 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
6636 and the specified suffix. */
6638 tree
6640 {
6647 #ifdef TARGET_DLLIMPORT_DECL_ATTRIBUTES
6648 /* A variable using the Stdcall convention (meaning we are running
6649 on a Windows box) live in a DLL. Here we adjust its name to use
6650 the jump-table, the _imp__NAME contains the address for the NAME
6651 variable. */
6652 {
6659 {
6664 }
6665 }
6666 #endif
6669 }
6671 /* Return the name to be used for GNAT_ENTITY. If a type, create a
6672 fully-qualified name, possibly with type information encoding.
6673 Otherwise, return the name. */
6675 tree
6677 {
6680 }
6682 /* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
6683 string, return a new IDENTIFIER_NODE that is the concatenation of
6684 the name in GNU_ID and SUFFIX. */
6686 tree
6688 {
6697 }