| blob | 6edda454a0c81742732112081b5368f52de76c9f |
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, 59 Temple Place - Suite 330, Boston, *
20 * MA 02111-1307, 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;
106 /* Given GNAT_ENTITY, an entity in the incoming GNAT tree, return a
107 GCC type corresponding to that entity. GNAT_ENTITY is assumed to
108 refer to an Ada type. */
110 tree
112 {
113 tree gnu_decl;
115 /* The back end never attempts to annotate generic types */
119 /* Convert the ada entity type into a GCC TYPE_DECL node. */
123 }
124 \f
125 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
126 entity, this routine returns the equivalent GCC tree for that entity
127 (an ..._DECL node) and associates the ..._DECL node with the input GNAT
128 defining identifier.
130 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
131 initial value (in GCC tree form). This is optional for variables.
132 For renamed entities, GNU_EXPR gives the object being renamed.
134 DEFINITION is nonzero if this call is intended for a definition. This is
135 used for separate compilation where it necessary to know whether an
136 external declaration or a definition should be created if the GCC equivalent
137 was not created previously. The value of 1 is normally used for a non-zero
138 DEFINITION, but a value of 2 is used in special circumstances, defined in
139 the code. */
141 tree
143 {
144 tree gnu_entity_id;
146 /* Contains the gnu XXXX_DECL tree node which is equivalent to the input
147 GNAT tree. This node will be associated with the GNAT node by calling
148 the save_gnu_tree routine at the end of the `switch' statement. */
150 /* true if we have already saved gnu_decl as a gnat association. */
152 /* Nonzero if we incremented defer_incomplete_level. */
154 /* Nonzero if we incremented force_global. */
156 /* Nonzero if we should check to see if elaborated during processing. */
158 /* Nonzero if we made GNU_DECL and its type here. */
164 Entity_Id gnat_temp;
165 unsigned int esize
175 bool imported_p
180 /* Since a use of an Itype is a definition, process it as such if it
181 is not in a with'ed unit. */
186 {
187 /* Ensure that we are in a subprogram mentioned in the Scope
188 chain of this entity, our current scope is global,
189 or that we encountered a task or entry (where we can't currently
190 accurately check scoping). */
193 {
196 }
200 {
205 gnat_temp
217 && (current_function_decl
219 {
222 }
223 }
225 /* This abort means the entity "gnat_entity" has an incorrect scope,
226 i.e. that its scope does not correspond to the subprogram in which
227 it is declared */
229 }
231 /* If this is entity 0, something went badly wrong. */
234 /* If we've already processed this entity, return what we got last time.
235 If we are defining the node, we should not have already processed it.
236 In that case, we will abort below when we try to save a new GCC tree for
237 this object. We also need to handle the case of getting a dummy type
238 when a Full_View exists. */
241 && (! definition
243 {
250 {
256 }
259 }
261 /* If this is a numeric or enumeral type, or an access type, a nonzero
262 Esize must be specified unless it was specified by the programmer. */
270 /* Likewise, RM_Size must be specified for all discrete and fixed-point
271 types. */
275 /* Get the name of the entity and set up the line number and filename of
276 the original definition for use in any decl we make. */
280 /* If we get here, it means we have not yet done anything with this
281 entity. If we are not defining it here, it must be external,
282 otherwise we should have defined it already. */
289 /* For cases when we are not defining (i.e., we are referencing from
290 another compilation unit) Public entities, show we are at global level
291 for the purpose of computing scopes. Don't do this for components or
292 discriminants since the relevant test is whether or not the record is
293 being defined. But do this for Imported functions or procedures in
294 all cases. */
302 /* Handle any attributes directly attached to the entity. */
306 /* Machine_Attributes on types are expected to be propagated to subtypes.
307 The corresponding Gigi_Rep_Items are only attached to the first subtype
308 though, so we handle the propagation here. */
315 {
317 /* If this is a use of a deferred constant, get its full
318 declaration. */
320 {
325 }
327 /* If we have an external constant that we are not defining,
328 get the expression that is was defined to represent. We
329 may throw that expression away later if it is not a
330 constant.
331 Do not retrieve the expression if it is an aggregate, because
332 in complex instantiation contexts it may not be expanded */
341 /* Ignore deferred constant definitions; they are processed fully in the
342 front-end. For deferred constant references, get the full
343 definition. On the other hand, constants that are renamings are
344 handled like variable renamings. If No_Initialization is set, this is
345 not a deferred constant but a constant whose value is built
346 manually. */
351 {
355 }
358 {
363 }
368 /* We used to special case VMS exceptions here to directly map them to
369 their associated condition code. Since this code had to be masked
370 dynamically to strip off the severity bits, this caused trouble in
371 the GCC/ZCX case because the "type" pointers we store in the tables
372 have to be static. We now don't special case here anymore, and let
373 the regular processing take place, which leaves us with a regular
374 exception data object for VMS exceptions too. The condition code
375 mapping is taken care of by the front end and the bitmasking by the
376 runtime library. */
381 {
382 /* The GNAT record where the component was defined. */
385 /* If the variable is an inherited record component (in the case of
386 extended record types), just return the inherited entity, which
387 must be a FIELD_DECL. Likewise for discriminants.
388 For discriminants of untagged records which have explicit
389 stored discriminants, return the entity for the corresponding
390 stored discriminant. Also use Original_Record_Component
391 if the record has a private extension. */
399 {
400 gnu_decl
405 }
407 /* If the enclosing record has explicit stored discriminants,
408 then it is an untagged record. If the Corresponding_Discriminant
409 is not empty then this must be a renamed discriminant and its
410 Original_Record_Component must point to the corresponding explicit
411 stored discriminant (i.e., we should have taken the previous
412 branch). */
416 {
417 /* A tagged record has no explicit stored discriminants. */
421 gnu_decl
426 }
428 /* If the enclosing record has explicit stored discriminants,
429 then it is an untagged record. If the Corresponding_Discriminant
430 is not empty then this must be a renamed discriminant and its
431 Original_Record_Component must point to the corresponding explicit
432 stored discriminant (i.e., we should have taken the first
433 branch). */
440 /* Otherwise, if we are not defining this and we have no GCC type
441 for the containing record, make one for it. Then we should
442 have made our own equivalent. */
444 {
445 /* ??? If this is in a record whose scope is a protected
446 type and we have an Original_Record_Component, use it.
447 This is a workaround for major problems in protected type
448 handling. */
456 {
457 gnu_decl
463 }
469 }
471 else
472 /* Here we have no GCC type and this is a reference rather than a
473 definition. This should never happen. Most likely the cause is a
474 reference before declaration in the gnat tree for gnat_entity. */
476 }
482 /* Simple variables, loop variables, OUT parameters, and exceptions. */
483 object:
484 {
486 bool const_flag
499 {
503 else
505 }
507 /* Get the type after elaborating the renamed object. */
510 /* If this is a loop variable, its type should be the base type.
511 This is because the code for processing a loop determines whether
512 a normal loop end test can be done by comparing the bounds of the
513 loop against those of the base type, which is presumed to be the
514 size used for computation. But this is not correct when the size
515 of the subtype is smaller than the type. */
519 /* Reject non-renamed objects whose types are unconstrained arrays or
520 any object whose type is a dummy type or VOID_TYPE. */
526 {
529 }
531 /* If an alignment is specified, use it if valid. Note that
532 exceptions are objects but don't have alignments. We must do this
533 before we validate the size, since the alignment can affect the
534 size. */
536 {
542 }
544 /* If we are defining the object, see if it has a Size value and
545 validate it if so. If we are not defining the object and a Size
546 clause applies, simply retrieve the value. We don't want to ignore
547 the clause and it is expected to have been validated already. Then
548 get the new type, if any. */
557 {
558 gnu_type
564 }
566 /* If this object has self-referential size, it must be a record with
567 a default value. We are supposed to allocate an object of the
568 maximum size in this case unless it is a constant with an
569 initializing expression, in which case we can get the size from
570 that. Note that the resulting size may still be a variable, so
571 this may end up with an indirect allocation. */
575 {
577 gnu_size
578 = SUBSTITUTE_PLACEHOLDER_IN_EXPR
581 /* We may have no GNU_EXPR because No_Initialization is
582 set even though there's an Expression. */
587 gnu_size
589 (Etype
591 else
593 }
595 /* If the size is zero bytes, make it one byte since some linkers have
596 trouble with zero-sized objects. If the object will have a
597 template, that will make it nonzero so don't bother. Also avoid
598 doing that for an object renaming or an object with an address
599 clause, as we would lose useful information on the view size
600 (e.g. for null array slices) and we are not allocating the object
601 here anyway. */
610 /* If this is an atomic object with no specified size and alignment,
611 but where the size of the type is a constant, set the alignment to
612 the lowest power of two greater than the size, or to the
613 biggest meaningful alignment, whichever is smaller. */
617 {
620 BIGGEST_ALIGNMENT))
622 else
627 }
629 /* If the object is set to have atomic components, find the component
630 type and validate it.
632 ??? Note that we ignore Has_Volatile_Components on objects; it's
633 not at all clear what to do in that case. */
636 {
645 }
647 /* Now check if the type of the object allows atomic access. Note
648 that we must test the type, even if this object has size and
649 alignment to allow such access, because we will be going
650 inside the padded record to assign to the object. We could fix
651 this by always copying via an intermediate value, but it's not
652 clear it's worth the effort. */
656 /* If this is an aliased object with an unconstrained nominal subtype,
657 make a type that includes the template. */
661 {
662 tree gnu_fat
664 tree gnu_temp_type
667 gnu_type
671 }
673 #ifdef MINIMUM_ATOMIC_ALIGNMENT
674 /* If the size is a constant and no alignment is specified, force
675 the alignment to be the minimum valid atomic alignment. The
676 restriction on constant size avoids problems with variable-size
677 temporaries; if the size is variable, there's no issue with
678 atomic access. Also don't do this for a constant, since it isn't
679 necessary and can interfere with constant replacement. Finally,
680 do not do it for Out parameters since that creates an
681 size inconsistency with In parameters. */
690 #endif
692 /* Make a new type with the desired size and alignment, if needed. */
696 /* Make a volatile version of this object's type if we are to
697 make the object volatile. Note that 13.3(19) says that we
698 should treat other types of objects as volatile as well. */
708 /* Convert the expression to the type of the object except in the
709 case where the object's type is unconstrained or the object's type
710 is a padded record whose field is of self-referential size. In
711 the former case, converting will generate unnecessary evaluations
712 of the CONSTRUCTOR to compute the size and in the latter case, we
713 want to only copy the actual data. */
719 && (CONTAINS_PLACEHOLDER_P
723 /* See if this is a renaming. If this is a constant renaming, treat
724 it as a normal variable whose initial value is what is being
725 renamed. We cannot do this if the type is unconstrained or
726 class-wide.
728 Otherwise, if what we are renaming is a reference, we can simply
729 return a stabilized version of that reference, after forcing any
730 SAVE_EXPRs to be evaluated. But, if this is at global level, we
731 can only do this if we know no SAVE_EXPRs will be made.
733 Otherwise, make this into a constant pointer to the object we are
734 to rename. */
737 {
738 /* If the renamed object had padding, strip off the reference
739 to the inner object and reset our type. */
743 && (TYPE_IS_PADDING_P
745 {
748 }
756 ;
758 /* If this is a declaration or reference that we can stabilize,
759 just use that declaration or reference as this entity unless
760 the latter has to be materialized. */
766 {
771 }
773 /* Otherwise, make this into a constant pointer to the object we
774 are to rename.
776 Stabilize it if we are not at the global level since in this
777 case the renaming evaluation may directly dereference the
778 initial value we make here instead of the pointer we will
779 assign it to. We don't want variables in the expression to be
780 evaluated every time the renaming is used, since the value of
781 these variables may change in between.
783 If we are at the global level and the value is not constant,
784 create_var_decl generates a mere elaboration assignment and
785 does not attach the initial expression to the declaration.
786 There is no possible direct initial-value dereference then. */
787 else
788 {
795 {
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 obect 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. */
938 {
943 {
944 gnu_alloc_type
948 &&
951 else
952 gnu_expr
953 = build_component_ref
957 }
963 gnat_entity);
967 }
968 else
969 {
972 }
973 }
975 /* If this object would go into the stack and has an alignment
976 larger than the default largest alignment, make a variable
977 to hold the "aligning type" with a modified initial value,
978 if any, then point to it and make that the value of this
979 variable, which is now indirect. */
982 {
983 tree gnu_new_type
986 tree gnu_new_var;
988 gnu_new_var
994 add_stmt_with_node
996 build_component_ref
999 gnu_expr),
1000 gnat_entity);
1003 gnu_expr
1004 = build_unary_op
1012 }
1014 /* Convert the expression to the type of the object except in the
1015 case where the object's type is unconstrained or the object's type
1016 is a padded record whose field is of self-referential size. In
1017 the former case, converting will generate unnecessary evaluations
1018 of the CONSTRUCTOR to compute the size and in the latter case, we
1019 want to only copy the actual data. */
1025 && (CONTAINS_PLACEHOLDER_P
1029 /* If this name is external or there was a name specified, use it,
1030 unless this is a VMS exception object since this would conflict
1031 with the symbol we need to export in addition. Don't use the
1032 Interface_Name if there is an address clause (see CD30005). */
1042 {
1047 }
1049 /* If this is constant initialized to a static constant and the
1050 object has an aggregrate type, force it to be statically
1051 allocated. */
1067 /* If we have an address clause and we've made this indirect, it's
1068 not enough to merely mark the type as volatile since volatile
1069 references only conflict with other volatile references while this
1070 reference must conflict with all other references. So ensure that
1071 the dereferenced value has alias set 0. */
1080 STACK_CHECK_MAX_VAR_SIZE))))
1085 gnat_entity);
1087 /* If this is a public constant or we're not optimizing and we're not
1088 making a VAR_DECL for it, make one just for export or debugger
1089 use. Likewise if the address is taken or if the object or type is
1090 aliased. */
1097 {
1098 tree gnu_corr_var
1104 }
1106 /* If this is declared in a block that contains an block with an
1107 exception handler, we must force this variable in memory to
1108 suppress an invalid optimization. */
1113 /* Back-annotate the Alignment of the object if not already in the
1114 tree. Likewise for Esize if the object is of a constant size.
1115 But if the "object" is actually a pointer to an object, the
1116 alignment and size are the same as teh type, so don't back-annotate
1117 the values for the pointer. */
1124 {
1129 gnu_back_size
1134 }
1135 }
1139 /* Return a TYPE_DECL for "void" that we previously made. */
1144 /* A special case, for the types Character and Wide_Character in
1145 Standard, we do not list all the literals. So if the literals
1146 are not specified, make this an unsigned type. */
1148 {
1151 }
1153 /* Normal case of non-character type, or non-Standard character type */
1154 {
1155 /* Here we have a list of enumeral constants in First_Literal.
1156 We make a CONST_DECL for each and build into GNU_LITERAL_LIST
1157 the list to be places into TYPE_FIELDS. Each node in the list
1158 is a TREE_LIST node whose TREE_VALUE is the literal name
1159 and whose TREE_PURPOSE is the value of the literal.
1161 Esize contains the number of bits needed to represent the enumeral
1162 type, Type_Low_Bound also points to the first literal and
1163 Type_High_Bound points to the last literal. */
1165 Entity_Id gnat_literal;
1170 else
1178 {
1180 gnu_type);
1181 tree gnu_literal
1189 }
1193 /* Note that the bounds are updated at the end of this function
1194 because to avoid an infinite recursion when we get the bounds of
1195 this type, since those bounds are objects of this type. */
1196 }
1202 /* For integer types, just make a signed type the appropriate number
1203 of bits. */
1208 /* For modular types, make the unsigned type of the proper number of
1209 bits and then set up the modulus, if required. */
1210 {
1212 tree gnu_modulus;
1218 /* Find the smallest mode at least ESIZE bits wide and make a class
1219 using that mode. */
1224 ;
1230 /* Get the modulus in this type. If it overflows, assume it is because
1231 it is equal to 2**Esize. Note that there is no overflow checking
1232 done on unsigned type, so we detect the overflow by looking for
1233 a modulus of zero, which is otherwise invalid. */
1237 {
1242 }
1244 /* If we have to set TYPE_PRECISION different from its natural value,
1245 make a subtype to do do. Likewise if there is a modulus and
1246 it is not one greater than TYPE_MAX_VALUE. */
1250 {
1267 }
1268 }
1277 /* For integral subtypes, we make a new INTEGER_TYPE. Note
1278 that we do not want to call build_range_type since we would
1279 like each subtype node to be distinct. This will be important
1280 when memory aliasing is implemented.
1282 The TREE_TYPE field of the INTEGER_TYPE we make points to the
1283 parent type; this fact is used by the arithmetic conversion
1284 functions.
1286 We elaborate the Ancestor_Subtype if it is not in the current
1287 unit and one of our bounds is non-static. We do this to ensure
1288 consistent naming in the case where several subtypes share the same
1289 bounds by always elaborating the first such subtype first, thus
1290 using its name. */
1302 {
1305 }
1313 gnat_entity,
1320 gnat_entity,
1324 /* One of the above calls might have caused us to be elaborated,
1325 so don't blow up if so. */
1327 {
1330 }
1335 /* This should be an unsigned type if the lower bound is constant
1336 and non-negative or if the base type is unsigned; a signed type
1337 otherwise. */
1347 /* If the type we are dealing with is to represent a packed array,
1348 we need to have the bits left justified on big-endian targets
1349 and right justified on little-endian targets. We also need to
1350 ensure that when the value is read (e.g. for comparison of two
1351 such values), we only get the good bits, since the unused bits
1352 are uninitialized. Both goals are accomplished by wrapping the
1353 modular value in an enclosing struct. */
1355 {
1357 tree gnu_field;
1366 /* Create a stripped-down declaration of the original type, mainly
1367 for debugging. */
1371 /* Don't notify the field as "addressable", since we won't be taking
1372 it's address and it would prevent create_field_decl from making a
1373 bitfield. */
1380 }
1385 /* If this is a VAX floating-point type, use an integer of the proper
1386 size. All the operations will be handled with ASM statements. */
1388 {
1393 sizetype));
1395 }
1397 /* The type of the Low and High bounds can be our type if this is
1398 a type from Standard, so set them at the end of the function. */
1406 {
1409 }
1411 {
1438 /* One of the above calls might have caused us to be elaborated,
1439 so don't blow up if so. */
1441 {
1444 }
1447 }
1450 /* Array and String Types and Subtypes
1452 Unconstrained array types are represented by E_Array_Type and
1453 constrained array types are represented by E_Array_Subtype. There
1454 are no actual objects of an unconstrained array type; all we have
1455 are pointers to that type.
1457 The following fields are defined on array types and subtypes:
1459 Component_Type Component type of the array.
1460 Number_Dimensions Number of dimensions (an int).
1461 First_Index Type of first index. */
1465 {
1471 int firstdim
1473 int nextdim
1479 tree gnu_max_size_unit;
1481 Entity_Id gnat_ind_subtype;
1482 Entity_Id gnat_ind_base_subtype;
1483 tree gnu_template_reference;
1484 tree tem;
1492 /* Make a node for the array. If we are not defining the array
1493 suppress expanding incomplete types and save the node as the type
1494 for GNAT_ENTITY. */
1497 {
1498 defer_incomplete_level++;
1505 }
1507 /* Build the fat pointer type. Use a "void *" object instead of
1508 a pointer to the array type since we don't have the array type
1509 yet (it will reference the fat pointer via the bounds). */
1512 ptr_void_type_node,
1515 gnu_ptr_template,
1518 /* Make sure we can put this into a register. */
1522 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1523 is the fat pointer. This will be used to access the individual
1524 fields once we build them. */
1528 gnu_template_reference
1532 /* Now create the GCC type for each index and add the fields for
1533 that index to the template. */
1535 gnat_ind_base_subtype
1541 {
1543 tree gnu_ind_subtype
1545 tree gnu_base_subtype
1547 tree gnu_base_min
1549 tree gnu_base_max
1553 /* Make the FIELD_DECLs for the minimum and maximum of this
1554 type and then make extractions of that field from the
1555 template. */
1558 gnu_ind_subtype,
1562 gnu_ind_subtype,
1571 /* We can't use build_component_ref here since the template
1572 type isn't complete yet. */
1575 NULL_TREE);
1578 NULL_TREE);
1581 /* Make a range type with the new ranges, but using
1582 the Ada subtype. Then we convert to sizetype. */
1588 /* Update the maximum size of the array, in elements. */
1589 gnu_max_size
1593 gnu_base_min)));
1597 }
1600 gnu_template_fields
1603 /* Install all the fields into the template. */
1608 /* Now make the array of arrays and update the pointer to the array
1609 in the fat pointer. Note that it is the first field. */
1613 /* Get and validate any specified Component_Size, but if Packed,
1614 ignore it since the front end will have taken care of it. */
1615 gnu_comp_size
1617 gnat_entity,
1625 /* If the component type is a RECORD_TYPE that has a self-referential
1626 size, use the maxium size. */
1632 {
1636 }
1642 /* If Component_Size is not already specified, annotate it with the
1643 size of the component. */
1653 gnu_max_size),
1657 {
1661 /* If the type below this an multi-array type, then this
1662 does not not have aliased components.
1664 ??? Otherwise, for now, we say that any component of aggregate
1665 type is addressable because the front end may take 'Reference
1666 of it. But we have to make it addressable if it must be passed
1667 by reference or it that is the default. */
1673 }
1675 /* If an alignment is specified, use it if valid. But ignore it for
1676 types that represent the unpacked base type for packed arrays. */
1679 {
1684 }
1690 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
1691 corresponding fat pointer. */
1698 /* If the maximum size doesn't overflow, use it. */
1713 /* Create a record type for the object and its template and
1714 set the template at a negative offset. */
1726 /* Give the thin pointer type a name. */
1730 gnat_entity);
1731 }
1737 /* This is the actual data type for array variables. Multidimensional
1738 arrays are implemented in the gnu tree as arrays of arrays. Note
1739 that for the moment arrays which have sparse enumeration subtypes as
1740 index components create sparse arrays, which is obviously space
1741 inefficient but so much easier to code for now.
1743 Also note that the subtype never refers to the unconstrained
1744 array type, which is somewhat at variance with Ada semantics.
1746 First check to see if this is simply a renaming of the array
1747 type. If so, the result is the array type. */
1752 else
1753 {
1756 int first_dim
1759 int next_dim
1761 Entity_Id gnat_ind_subtype;
1762 Entity_Id gnat_ind_base_subtype;
1767 tree gnu_max_size_unit;
1771 /* First create the gnu types for each index. Create types for
1772 debugging information to point to the index types if the
1773 are not integer types, have variable bounds, or are
1774 wider than sizetype. */
1777 gnat_ind_base_subtype
1783 {
1784 tree gnu_index_subtype
1786 tree gnu_min
1788 tree gnu_max
1790 tree gnu_base_subtype
1792 tree gnu_base_min
1794 tree gnu_base_max
1797 tree gnu_base_base_min
1799 tree gnu_base_base_max
1801 tree gnu_high;
1802 tree gnu_this_max;
1804 /* If the minimum and maximum values both overflow in
1805 SIZETYPE, but the difference in the original type
1806 does not overflow in SIZETYPE, ignore the overflow
1807 indications. */
1815 && (!TREE_OVERFLOW
1823 /* Similarly, if the range is null, use bounds of 1..0 for
1824 the sizetype bounds. */
1836 /* Now compute the size of this bound. We need to provide
1837 GCC with an upper bound to use but have to deal with the
1838 "superflat" case. There are three ways to do this. If we
1839 can prove that the array can never be superflat, we can
1840 just use the high bound of the index subtype. If we can
1841 prove that the low bound minus one can't overflow, we
1842 can do this as MAX (hb, lb - 1). Otherwise, we have to use
1843 the expression hb >= lb ? hb : lb - 1. */
1846 /* See if the base array type is already flat. If it is, we
1847 are probably compiling an ACVC test, but it will cause the
1848 code below to malfunction if we don't handle it specially. */
1856 /* If gnu_high is now an integer which overflowed, the array
1857 cannot be superflat. */
1864 else
1865 gnu_high
1866 = build_cond_expr
1874 /* Also compute the maximum size of the array. Here we
1875 see if any constraint on the index type of the base type
1876 can be used in the case of self-referential bound on
1877 the index type of the subtype. We look for a non-"infinite"
1878 and non-self-referential bound from any type involved and
1879 handle each bound separately. */
1904 gnu_this_max
1908 gnu_base_min)),
1909 size_zero_node);
1915 gnu_max_size
1929 }
1931 /* Then flatten: create the array of arrays. */
1935 /* One of the above calls might have caused us to be elaborated,
1936 so don't blow up if so. */
1938 {
1941 }
1943 /* Get and validate any specified Component_Size, but if Packed,
1944 ignore it since the front end will have taken care of it. */
1945 gnu_comp_size
1947 gnat_entity,
1952 /* If the component type is a RECORD_TYPE that has a self-referential
1953 size, use the maxium size. */
1959 {
1964 }
1978 {
1981 /* If the type below this an multi-array type, then this
1982 does not not have aliased components.
1984 ??? Otherwise, for now, we say that any component of aggregate
1985 type is addressable because the front end may take 'Reference
1986 of it. But we have to make it addressable if it must be passed
1987 by reference or it that is the default. */
1993 }
1995 /* If we are at file level and this is a multi-dimensional array, we
1996 need to make a variable corresponding to the stride of the
1997 inner dimensions. */
1999 {
2001 tree gnu_arr_type;
2007 {
2015 /* ??? For now, store the size as a multiple of the
2016 alignment of the element type in bytes so that we
2017 can see the alignment from the tree. */
2019 = build_binary_op
2021 elaborate_expression_1
2030 }
2031 }
2033 /* If we need to write out a record type giving the names of
2034 the bounds, do it now. */
2036 {
2039 tree gnu_field;
2045 {
2046 tree gnu_type_name
2053 integer_type_node,
2054 gnu_bound_rec_type,
2058 }
2062 }
2069 /* If our size depends on a placeholder and the maximum size doesn't
2070 overflow, use it. */
2077 {
2083 }
2085 /* Set our alias set to that of our base type. This gives all
2086 array subtypes the same alias set. */
2088 }
2090 /* If this is a packed type, make this type the same as the packed
2091 array type, but do some adjusting in the type first. */
2094 {
2095 Entity_Id gnat_index;
2096 tree gnu_inner_type;
2098 /* First finish the type we had been making so that we output
2099 debugging information for it */
2100 gnu_type
2103 | (TYPE_QUAL_VOLATILE
2111 /* Save it as our equivalent in case the call below elaborates
2112 this type again. */
2126 /* We need to point the type we just made to our index type so
2127 the actual bounds can be put into a template. */
2133 {
2135 {
2136 /* The TYPE_ACTUAL_BOUNDS field is also used for the modulus.
2137 If it is, we need to make another type. */
2139 {
2140 tree gnu_subtype;
2157 }
2160 }
2166 SET_TYPE_ACTUAL_BOUNDS
2173 SET_TYPE_ACTUAL_BOUNDS
2180 }
2181 }
2183 /* Abort if packed array with no packed array type field set. */
2184 else
2190 /* Create the type for a string literal. */
2191 {
2192 Entity_Id gnat_full_type
2197 tree gnu_string_array_type
2199 tree gnu_string_index_type
2202 tree gnu_lower_bound
2207 tree gnu_upper_bound
2209 gnu_lower_bound,
2211 tree gnu_range_type
2214 tree gnu_index_type
2219 gnu_range_type);
2221 gnu_type
2223 gnu_index_type);
2224 }
2227 /* Record Types and Subtypes
2229 The following fields are defined on record types:
2231 Has_Discriminants True if the record has discriminants
2232 First_Discriminant Points to head of list of discriminants
2233 First_Entity Points to head of list of fields
2234 Is_Tagged_Type True if the record is tagged
2236 Implementation of Ada records and discriminated records:
2238 A record type definition is transformed into the equivalent of a C
2239 struct definition. The fields that are the discriminants which are
2240 found in the Full_Type_Declaration node and the elements of the
2241 Component_List found in the Record_Type_Definition node. The
2242 Component_List can be a recursive structure since each Variant of
2243 the Variant_Part of the Component_List has a Component_List.
2245 Processing of a record type definition comprises starting the list of
2246 field declarations here from the discriminants and the calling the
2247 function components_to_record to add the rest of the fields from the
2248 component list and return the gnu type node. The function
2249 components_to_record will call itself recursively as it traverses
2250 the tree. */
2254 {
2255 gnu_type
2256 = build_complex_type
2257 (get_unpadded_type
2260 (Component_List
2261 (Type_Definition
2265 }
2267 {
2270 Entity_Id gnat_field;
2271 tree gnu_field;
2273 tree gnu_get_parent;
2280 bool is_extension
2284 /* See if all fields have a rep clause. Stop when we find one
2285 that doesn't. */
2294 /* If this is a record extension, go a level further to find the
2295 record definition. Also, verify we have a Parent_Subtype. */
2297 {
2304 }
2306 /* Make a node for the record. If we are not defining the record,
2307 suppress expanding incomplete types and save the node as the type
2308 for GNAT_ENTITY. We use the same RECORD_TYPE as for a dummy type
2309 and reset TYPE_DUMMY_P to show it's no longer a dummy.
2311 It is very tempting to delay resetting this bit until we are done
2312 with completing the type, e.g. to let possible intermediate
2313 elaboration of access types designating the record know it is not
2314 complete and arrange for update_pointer_to to fix things up later.
2316 It would be wrong, however, because dummy types are expected only
2317 to be created for Ada incomplete or private types, which is not
2318 what we have here. Doing so would make other parts of gigi think
2319 we are dealing with a really incomplete or private type, and have
2320 nasty side effects, typically on the generation of the associated
2321 debugging information. */
2332 {
2333 defer_incomplete_level++;
2340 }
2342 /* If both a size and rep clause was specified, put the size in
2343 the record type now so that it can get the proper mode. */
2347 /* Always set the alignment here so that it can be used to
2348 set the mode, if it is making the alignment stricter. If
2349 it is invalid, it will be checked again below. If this is to
2350 be Atomic, choose a default alignment of a word unless we know
2351 the size and it's smaller. */
2360 /* If we have a Parent_Subtype, make a field for the parent. If
2361 this record has rep clauses, force the position to zero. */
2363 {
2364 tree gnu_parent;
2366 /* A major complexity here is that the parent subtype will
2367 reference our discriminants. But those must reference
2368 the parent component of this record. So here we will
2369 initialize each of those components to a COMPONENT_REF.
2370 The first operand of that COMPONENT_REF is another
2371 COMPONENT_REF which will be filled in below, once
2372 the parent type can be safely built. */
2377 NULL_TREE),
2378 NULL_TREE);
2385 save_gnu_tree
2389 gnu_get_parent,
2393 NULL_TREE),
2398 gnu_field_list
2408 }
2410 /* Add the fields for the discriminants into the record. */
2416 {
2417 /* If this is a record extension and this discriminant
2418 is the renaming of another discriminant, we've already
2419 handled the discriminant above. */
2424 gnu_field
2427 /* Make an expression using a PLACEHOLDER_EXPR from the
2428 FIELD_DECL node just created and link that with the
2429 corresponding GNAT defining identifier. Then add to the
2430 list of fields. */
2440 }
2442 /* Put the discriminants into the record (backwards), so we can
2443 know the appropriate discriminant to use for the names of the
2444 variants. */
2447 /* Add the listed fields into the record and finish up. */
2455 /* If this is an extension type, reset the tree for any
2456 inherited discriminants. Also remove the PLACEHOLDER_EXPR
2457 for non-inherited discriminants. */
2463 {
2467 else
2468 {
2473 }
2474 }
2476 /* If it is a tagged record force the type to BLKmode to insure
2477 that these objects will always be placed in memory. Do the
2478 same thing for limited record types. */
2482 /* If this is a derived type, we must make the alias set of this type
2483 the same as that of the type we are derived from. We assume here
2484 that the other type is already frozen. */
2490 /* Fill in locations of fields. */
2493 /* If there are any entities in the chain corresponding to
2494 components that we did not elaborate, ensure we elaborate their
2495 types if they are Itypes. */
2503 }
2507 /* If an equivalent type is present, that is what we should use.
2508 Otherwise, fall through to handle this like a record subtype
2509 since it may have constraints. */
2512 {
2517 }
2519 /* ... fall through ... */
2523 /* If Cloned_Subtype is Present it means this record subtype has
2524 identical layout to that type or subtype and we should use
2525 that GCC type for this one. The front end guarantees that
2526 the component list is shared. */
2528 {
2532 }
2534 /* Otherwise, first ensure the base type is elaborated. Then, if we are
2535 changing the type, make a new type with each field having the
2536 type of the field in the new subtype but having the position
2537 computed by transforming every discriminant reference according
2538 to the constraints. We don't see any difference between
2539 private and nonprivate type here since derivations from types should
2540 have been deferred until the completion of the private type. */
2541 else
2542 {
2544 tree gnu_base_type;
2545 tree gnu_orig_type;
2550 /* Get the base type initially for its alignment and sizes. But
2551 if it is a padded type, we do all the other work with the
2552 unpadded type. */
2561 {
2564 }
2566 /* When the type has discriminants, and these discriminants
2567 affect the shape of what it built, factor them in.
2569 If we are making a subtype of an Unchecked_Union (must be an
2570 Itype), just return the type.
2572 We can't just use Is_Constrained because private subtypes without
2573 discriminants of full types with discriminants with default
2574 expressions are Is_Constrained but aren't constrained! */
2582 {
2583 Entity_Id gnat_field;
2584 Entity_Id gnat_root_type;
2586 tree gnu_pos_list
2589 BIGGEST_ALIGNMENT);
2590 tree gnu_subst_list
2592 definition);
2594 tree gnu_temp;
2596 /* If this is a derived type, we may be seeing fields from any
2597 original records, so add those positions and discriminant
2598 substitutions to our lists. */
2602 {
2603 gnu_pos_list
2604 = compute_field_positions
2607 BIGGEST_ALIGNMENT);
2610 {
2611 gnu_subst_list
2614 definition);
2616 /* If there's a _Parent field, it may overlap the
2617 fields we have that appear to be in this record but
2618 actually are from the parent. So make note of that
2619 fact and later we'll make a UNION_TYPE instead of
2620 a RECORD_TYPE, since the latter may not have
2621 overlapping fields. */
2623 }
2624 }
2631 gnat_entity);
2638 {
2639 tree gnu_old_field
2640 = gnat_to_gnu_entity
2642 tree gnu_offset
2644 gnu_pos_list));
2647 tree gnu_field_type
2651 unsigned int offset_align
2654 tree gnu_field;
2656 /* If there was a component clause, the field types must be
2657 the same for the type and subtype, so copy the data from
2658 the old field to avoid recomputation here. Also if the
2659 field is justified modular and the optimization in
2660 gnat_to_gnu_field was applied. */
2667 {
2670 }
2672 /* If this was a bitfield, get the size from the old field.
2673 Also ensure the type can be placed into a bitfield. */
2675 {
2681 }
2690 /* If the size is now a constant, we can set it as the
2691 size of the field when we make it. Otherwise, we need
2692 to deal with it specially. */
2696 gnu_field
2697 = create_field_decl
2703 {
2712 bitsize_unit_node));
2714 }
2718 SET_DECL_ORIGINAL_FIELD
2729 }
2734 /* Now set the size, alignment and alias set of the new type to
2735 match that of the old one, doing any substitutions, as
2736 above. */
2762 SET_TYPE_ADA_SIZE
2767 /* Recompute the mode of this record type now that we know its
2768 actual size. */
2771 /* Fill in locations of fields. */
2773 }
2775 /* If we've made a new type, record it and make an XVS type to show
2776 what this is a subtype of. Some debuggers require the XVS
2777 type to be output first, so do it in that order. */
2779 {
2781 {
2792 integer_type_node,
2793 gnu_subtype_marker,
2797 }
2804 }
2806 /* Otherwise, go down all the components in the new type and
2807 make them equivalent to those in the base type. */
2808 else
2815 get_gnu_tree
2817 }
2822 /* If we are not defining this entity, and we have incomplete
2823 entities being processed above us, make a dummy type and
2824 fill it in later. */
2826 {
2830 gnu_type
2831 = build_pointer_type
2844 }
2846 /* ... fall through ... */
2853 {
2855 Entity_Id gnat_desig_full
2857 Incomplete_Or_Private_Kind))
2859 /* We want to know if we'll be seeing the freeze node for any
2860 incomplete type we may be pointing to. */
2861 bool in_main_unit
2877 {
2879 {
2883 }
2885 Incomplete_Or_Private_Kind))
2887 }
2892 /* If either the designated type or its full view is an
2893 unconstrained array subtype, replace it with the type it's a
2894 subtype of. This avoids problems with multiple copies of
2895 unconstrained array types. */
2904 /* If the designated type is a subtype of an incomplete record type,
2905 use the parent type to avoid order of elaboration issues. This
2906 can lose some code efficiency, but there is no alternative. */
2912 /* If we are pointing to an incomplete type whose completion is an
2913 unconstrained array, make a fat pointer type instead of a pointer
2914 to VOID. The two types in our fields will be pointers to VOID and
2915 will be replaced in update_pointer_to. Similiarly, if the type
2916 itself is a dummy type or an unconstrained array. Also make
2917 a dummy TYPE_OBJECT_RECORD_TYPE in case we have any thin
2918 pointers to it. */
2934 && defer_incomplete_level
2938 {
2939 tree gnu_old
2943 tree fields;
2945 /* Show the dummy we get will be a fat pointer. */
2948 /* If the call above got something that has a pointer, that
2949 pointer is our type. This could have happened either
2950 because the type was elaborated or because somebody
2951 else executed the code below. */
2954 {
2960 fields
2962 create_field_decl
2967 ptr_void_type_node,
2970 /* Make sure we can place this into a register. */
2981 }
2982 }
2984 /* If we already know what the full type is, use it. */
2989 /* Get the type of the thing we are to point to and build a pointer
2990 to it. If it is a reference to an incomplete or private type with a
2991 full view that is a record, make a dummy type node and get the
2992 actual type later when we have verified it is safe. */
2998 {
3001 }
3003 /* Likewise if we are pointing to a record or array and we are to defer
3004 elaborating incomplete types. We do this since this access type
3005 may be the full view of some private type. Note that the
3006 unconstrained array case is handled above. */
3014 {
3017 }
3019 {
3020 gnu_type
3022 p_mode,
3025 }
3026 else
3029 /* It is possible that the above call to gnat_to_gnu_type resolved our
3030 type. If so, just return it. */
3032 {
3035 }
3037 /* If we have a GCC type for the designated type, possibly modify it
3038 if we are pointing only to constant objects and then make a pointer
3039 to it. Don't do this for unconstrained arrays. */
3041 {
3044 {
3045 gnu_desig_type
3046 = build_qualified_type
3050 /* Some extra processing is required if we are building a
3051 pointer to an incomplete type (in the GCC sense). We might
3052 have such a type if we just made a dummy, or directly out
3053 of the call to gnat_to_gnu_type above if we are processing
3054 an access type for a record component designating the
3055 record type itself. */
3057 {
3058 /* We must ensure that the pointer to variant we make will
3059 be processed by update_pointer_to when the initial type
3060 is completed. Pretend we made a dummy and let further
3061 processing act as usual. */
3064 /* We must ensure that update_pointer_to will not retrieve
3065 the dummy variant when building a properly qualified
3066 version of the complete type. We take advantage of the
3067 fact that get_qualified_type is requiring TYPE_NAMEs to
3068 match to influence build_qualified_type and then also
3069 update_pointer_to here. */
3072 }
3073 }
3075 gnu_type
3078 }
3080 /* If we are not defining this object and we made a dummy pointer,
3081 save our current definition, evaluate the actual type, and replace
3082 the tentative type we made with the actual one. If we are to defer
3083 actually looking up the actual type, make an entry in the
3084 deferred list. */
3087 {
3088 tree gnu_old_type
3094 gnu_type
3095 = build_pointer_type
3096 (TYPE_OBJECT_RECORD_TYPE
3106 /* Note that the call to gnat_to_gnu_type here might have
3107 updated gnu_old_type directly, in which case it is not a
3108 dummy type any more when we get into update_pointer_to.
3110 This may happen for instance when the designated type is a
3111 record type, because their elaboration starts with an
3112 initial node from make_dummy_type, which may yield the same
3113 node as the one we got.
3115 Besides, variants of this non-dummy type might have been
3116 created along the way. update_pointer_to is expected to
3117 properly take care of those situations. */
3120 else
3121 {
3129 }
3130 }
3131 }
3138 else
3139 /* The runtime representation is the equivalent type. */
3153 /* We treat this as identical to its base type; any constraint is
3154 meaningful only to the front end.
3156 The designated type must be elaborated as well, if it does
3157 not have its own freeze node. Designated (sub)types created
3158 for constrained components of records with discriminants are
3159 not frozen by the front end and thus not elaborated by gigi,
3160 because their use may appear before the base type is frozen,
3161 and because it is not clear that they are needed anywhere in
3162 Gigi. With the current model, there is no correct place where
3163 they could be elaborated. */
3170 {
3171 /* If we are not defining this entity, and we have incomplete
3172 entities being processed above us, make a dummy type and
3173 elaborate it later. */
3175 {
3178 tree gnu_ptr_type
3179 = build_pointer_type
3186 }
3189 Incomplete_Or_Private_Kind))
3190 ;
3191 else
3194 }
3199 /* Subprogram Entities
3201 The following access functions are defined for subprograms (functions
3202 or procedures):
3204 First_Formal The first formal parameter.
3205 Is_Imported Indicates that the subprogram has appeared in
3206 an INTERFACE or IMPORT pragma. For now we
3207 assume that the external language is C.
3208 Is_Inlined True if the subprogram is to be inlined.
3210 In addition for function subprograms we have:
3212 Etype Return type of the function.
3214 Each parameter is first checked by calling must_pass_by_ref on its
3215 type to determine if it is passed by reference. For parameters which
3216 are copied in, if they are Ada IN OUT or OUT parameters, their return
3217 value becomes part of a record which becomes the return type of the
3218 function (C function - note that this applies only to Ada procedures
3219 so there is no Ada return type). Additional code to store back the
3220 parameters will be generated on the caller side. This transformation
3221 is done here, not in the front-end.
3223 The intended result of the transformation can be seen from the
3224 equivalent source rewritings that follow:
3226 struct temp {int a,b};
3227 procedure P (A,B: IN OUT ...) is temp P (int A,B) {
3228 .. ..
3229 end P; return {A,B};
3230 }
3231 procedure call
3233 {
3234 temp t;
3235 P(X,Y); t = P(X,Y);
3236 X = t.a , Y = t.b;
3237 }
3239 For subprogram types we need to perform mainly the same conversions to
3240 GCC form that are needed for procedures and function declarations. The
3241 only difference is that at the end, we make a type declaration instead
3242 of a function declaration. */
3247 {
3248 /* The first GCC parameter declaration (a PARM_DECL node). The
3249 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3250 actually is the head of this parameter list. */
3252 /* The type returned by a function. If the subprogram is a procedure
3253 this type should be void_type_node. */
3255 /* List of fields in return type of procedure with copy in copy out
3256 parameters. */
3258 /* Non-null for subprograms containing parameters passed by copy in
3259 copy out (Ada IN OUT or OUT parameters not passed by reference),
3260 in which case it is the list of nodes used to specify the values of
3261 the in out/out parameters that are returned as a record upon
3262 procedure return. The TREE_PURPOSE of an element of this list is
3263 a field of the record and the TREE_VALUE is the PARM_DECL
3264 corresponding to that field. This list will be saved in the
3265 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3267 /* If an import pragma asks to map this subprogram to a GCC builtin,
3268 this is the builtin DECL node. */
3270 Entity_Id gnat_param;
3273 bool extern_flag
3285 /* A parameter may refer to this type, so defer completion
3286 of any incomplete types. */
3289 /* If the subprogram has an alias, it is probably inherited, so
3290 we can use the original one. If the original "subprogram"
3291 is actually an enumeration literal, it may be the first use
3292 of its type, so we must elaborate that type now. */
3294 {
3301 /* Elaborate any Itypes in the parameters of this entity. */
3309 }
3311 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3312 corresponding DECL node.
3314 We still want the parameter associations to take place because the
3315 proper generation of calls depends on it (a GNAT parameter without
3316 a corresponding GCC tree has a very specific meaning), so we don't
3317 just break here. */
3321 /* ??? What if we don't find the builtin node above ? warn ? err ?
3322 In the current state we neither warn nor err, and calls will just
3323 be handled as for regular subprograms. */
3328 /* If this function returns by reference, make the actual
3329 return type of this function the pointer and mark the decl. */
3331 {
3334 }
3336 /* If the Mechanism is By_Reference, ensure the return type uses
3337 the machine's by-reference mechanism, which may not the same
3338 as above (e.g., it might be by passing a fake parameter). */
3341 {
3344 }
3346 /* If we are supposed to return an unconstrained array,
3347 actually return a fat pointer and make a note of that. Return
3348 a pointer to an unconstrained record of variable size. */
3350 {
3353 }
3355 /* If the type requires a transient scope, the result is allocated
3356 on the secondary stack, so the result type of the function is
3357 just a pointer. */
3359 {
3362 }
3364 /* If the type is a padded type and the underlying type would not
3365 be passed by reference or this function has a foreign convention,
3366 return the underlying type. */
3374 /* If the return type is unconstrained, that means it must have a
3375 maximum size. We convert the function into a procedure and its
3376 caller will pass a pointer to an object of that maximum size as the
3377 first parameter when we call the function. */
3379 {
3381 gnu_param_list
3386 }
3388 /* If the return type has a size that overflows, we cannot have
3389 a function that returns that type. This usage doesn't make
3390 sense anyway, so give an error here. */
3393 {
3395 gnat_entity);
3401 }
3403 /* Look at all our parameters and get the type of
3404 each. While doing this, build a copy-out structure if
3405 we need one. */
3410 {
3420 /* Builtins are expanded inline and there is no real call sequence
3421 involved. so the type expected by the underlying expander is
3422 always the type of each argument "as is". */
3426 /* Otherwise, see if a Mechanism was supplied that forced this
3427 parameter to be passed one way or another. */
3431 ;
3439 {
3445 else
3447 }
3448 else
3451 /* If this is either a foreign function or if the
3452 underlying type won't be passed by refererence, strip off
3453 possible padding type. */
3461 /* If this is an IN parameter it is read-only, so make a variant
3462 of the type that is read-only.
3464 ??? However, if this is an unconstrained array, that type can
3465 be very complex. So skip it for now. Likewise for any other
3466 self-referential type. */
3470 gnu_param_type
3475 /* For foreign conventions, pass arrays as a pointer to the
3476 underlying type. First check for unconstrained array and get
3477 the underlying array. Then get the component type and build
3478 a pointer to it. */
3481 gnu_param_type
3486 gnu_param_type
3487 = build_pointer_type
3492 && !req_by_copy
3494 {
3495 /* Strip off any multi-dimensional entries, then strip
3496 off the last array to get the component type. */
3505 gnu_param_type
3511 }
3513 /* Fat pointers are passed as thin pointers for foreign
3514 conventions. */
3517 gnu_param_type
3521 /* If we must pass or were requested to pass by reference, do so.
3522 If we were requested to pass by copy, do so.
3523 Otherwise, for foreign conventions, pass all in out parameters
3524 or aggregates by reference. For COBOL and Fortran, pass
3525 all integer and FP types that way too. For Convention Ada,
3526 use the standard Ada default. */
3528 || (!req_by_copy
3538 /* For convention Ada, see if we pass by reference
3539 by default. */
3542 {
3545 }
3553 /* If this is an OUT parameter that isn't passed by reference
3554 and isn't a pointer or aggregate, we don't make a PARM_DECL
3555 for it. Instead, it will be a VAR_DECL created when we process
3556 the procedure. For the special parameter of Valued_Procedure,
3557 never pass it in.
3559 An exception is made to cover the RM-6.4.1 rule requiring "by
3560 copy" out parameters with discriminants or implicit initial
3561 values to be handled like in out parameters. These type are
3562 normally built as aggregates, and hence passed by reference,
3563 except for some packed arrays which end up encoded in special
3564 integer types.
3566 The exception we need to make is then for packed arrays of
3567 records with discriminants or implicit initial values. We have
3568 no light/easy way to check for the latter case, so we merely
3569 check for packed arrays of records. This may lead to useless
3570 copy-in operations, but in very rare cases only, as these would
3571 be exceptions in a set of already exceptional situations. */
3574 || (!by_descr_p
3582 else
3583 {
3584 gnu_param
3585 = create_param_decl
3587 by_ref_p || by_component_ptr_p
3601 /* If a parameter is a pointer, this function may modify
3602 memory through it and thus shouldn't be considered
3603 a pure function. Also, the memory may be modified
3604 between two calls, so they can't be CSE'ed. The latter
3605 case also handles by-ref parameters. */
3609 }
3612 {
3614 {
3619 }
3628 gnu_return_list);
3629 }
3630 }
3632 /* Do not compute record for out parameters if subprogram is
3633 stubbed since structures are incomplete for the back-end. */
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 _WIN32
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 else
3744 {
3749 gnat_entity);
3752 }
3753 }
3764 /* If this type does not have a full view in the unit we are
3765 compiling, then just get the type from its Etype. */
3767 {
3768 /* If this is an incomplete type with no full view, it must
3769 be a Taft Amendement type, so just return a dummy type. */
3776 else
3777 {
3781 }
3784 }
3786 /* Otherwise, if we are not defining the type now, get the
3787 type from the full view. But always get the type from the full
3788 view for define on use types, since otherwise we won't see them! */
3795 {
3800 }
3802 /* For incomplete types, make a dummy type entry which will be
3803 replaced later. */
3806 /* Save this type as the full declaration's type so we can do any needed
3807 updates when we see it. */
3814 /* Simple class_wide types are always viewed as their root_type
3815 by Gigi unless an Equivalent_Type is specified. */
3819 else
3831 else
3843 /* Nothing at all to do here, so just return an ERROR_MARK and claim
3844 we've already saved it, so we don't try to. */
3851 }
3853 /* If we had a case where we evaluated another type and it might have
3854 defined this one, handle it here. */
3856 {
3859 }
3861 /* If we are processing a type and there is either no decl for it or
3862 we just made one, do some common processing for the type, such as
3863 handling alignment and possible padding. */
3866 {
3874 /* ??? Don't set the size for a String_Literal since it is either
3875 confirming or we don't handle it properly (if the low bound is
3876 non-constant). */
3882 /* If a size was specified, see if we can make a new type of that size
3883 by rearranging the type, for example from a fat to a thin pointer. */
3885 {
3886 gnu_type
3893 }
3895 /* If the alignment hasn't already been processed and this is
3896 not an unconstrained array, see if an alignment is specified.
3897 If not, we pick a default alignment for atomic objects. */
3899 ;
3913 /* See if we need to pad the type. If we did, and made a record,
3914 the name of the new type may be changed. So get it back for
3915 us when we make the new TYPE_DECL below. */
3920 {
3924 }
3928 /* If we are at global level, GCC will have applied variable_size to
3929 the type, but that won't have done anything. So, if it's not
3930 a constant or self-referential, call elaborate_expression_1 to
3931 make a variable for the size rather than calculating it each time.
3932 Handle both the RM size and the actual size. */
3937 {
3941 {
3948 }
3949 else
3950 {
3957 /* ??? For now, store the size as a multiple of the alignment
3958 in bytes so that we can see the alignment from the tree. */
3960 = build_binary_op
3962 elaborate_expression_1
3973 SET_TYPE_ADA_SIZE
3976 gnat_entity,
3980 }
3981 }
3983 /* If this is a record type or subtype, call elaborate_expression_1 on
3984 any field position. Do this for both global and local types.
3985 Skip any fields that we haven't made trees for to avoid problems with
3986 class wide types. */
3991 {
3994 /* ??? Unfortunately, GCC needs to be able to prove the
3995 alignment of this offset and if it's a variable, it can't.
3996 In GCC 3.4, we'll use DECL_OFFSET_ALIGN in some way, but
3997 right now, we have to put in an explicit multiply and
3998 divide by that value. */
4001 = build_binary_op
4003 elaborate_expression_1
4012 }
4016 | (TYPE_QUAL_VOLATILE
4029 else
4031 }
4034 {
4037 /* Back-annotate the Alignment of the type if not already in the
4038 tree. Likewise for sizes. */
4044 {
4045 /* If the size is self-referential, we annotate the maximum
4046 value of that size. */
4055 {
4056 /* In this mode the tag and the parent components are not
4057 generated by the front-end, so the sizes must be adjusted
4058 explicitly now. */
4064 {
4065 size_offset
4069 }
4070 else
4078 }
4079 }
4083 }
4092 /* If we haven't already, associate the ..._DECL node that we just made with
4093 the input GNAT entity node. */
4097 /* If this is an enumeral or floating-point type, we were not able to set
4098 the bounds since they refer to the type. These bounds are always static.
4100 For enumeration types, also write debugging information and declare the
4101 enumeration literal table, if needed. */
4105 {
4108 /* If this is a padded type, we need to use the underlying type. */
4113 /* If this is a floating point type and we haven't set a floating
4114 point type yet, use this in the evaluation of the bounds. */
4124 {
4127 /* Since this has both a typedef and a tag, avoid outputting
4128 the name twice. */
4131 }
4132 }
4134 /* If we deferred processing of incomplete types, re-enable it. If there
4135 were no other disables and we have some to process, do so. */
4137 {
4143 {
4150 }
4151 }
4153 /* If we are not defining this type, see if it's in the incomplete list.
4154 If so, handle that list entry now. */
4156 {
4161 {
4165 }
4166 }
4169 force_global--;
4178 }
4179 \f
4180 /* Given GNAT_ENTITY, elaborate all expressions that are required to
4181 be elaborated at the point of its definition, but do nothing else. */
4183 void
4185 {
4187 {
4194 {
4198 /* ??? Tests for avoiding static constaint error expression
4199 is needed until the front stops generating bogus conversions
4200 on bounds of real types. */
4209 }
4212 {
4216 /* If this is a record extension, go a level further to find the
4217 record definition. */
4220 }
4230 {
4231 Node_Id gnat_discriminant_expr;
4232 Entity_Id gnat_field;
4235 gnat_discriminant_expr
4240 /* ??? For now, ignore access discriminants. */
4243 gnat_entity,
4245 }
4248 }
4249 }
4250 \f
4251 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
4252 any entities on its entity chain similarly. */
4254 void
4256 {
4257 Entity_Id gnat_sub_entity;
4260 /* If this has an entity list, process all in the list. */
4277 /* Now clear this if it has been defined, but only do so if it isn't
4278 a subprogram or parameter. We could refine this, but it isn't
4279 worth it. If this is statically allocated, it is supposed to
4280 hang around out of cope. */
4283 {
4286 }
4287 }
4288 \f
4289 /* Set the alias set of GNU_NEW_TYPE to be that of GNU_OLD_TYPE. If this
4290 is a multi-dimensional array type, do this recursively. */
4292 static void
4294 {
4298 {
4299 /* We need to be careful here in case GNU_OLD_TYPE is an unconstrained
4300 array. In that case, it doesn't have the same shape as GNU_NEW_TYPE,
4301 so we need to go down to what does. */
4303 gnu_old_type
4307 }
4311 }
4312 \f
4313 /* Return a TREE_LIST describing the substitutions needed to reflect
4314 discriminant substitutions from GNAT_SUBTYPE to GNAT_TYPE and add
4315 them to GNU_LIST. If GNAT_TYPE is not specified, use the base type
4316 of GNAT_SUBTYPE. The substitions can be in any order. TREE_PURPOSE
4317 gives the tree for the discriminant and TREE_VALUES is the replacement
4318 value. They are in the form of operands to substitute_in_expr.
4319 DEFINITION is as in gnat_to_gnu_entity. */
4321 static tree
4324 {
4325 Entity_Id gnat_discrim;
4326 Node_Id gnat_value;
4337 /* Ignore access discriminants. */
4340 elaborate_expression
4344 gnu_list);
4347 }
4348 \f
4349 /* For the following two functions: for each GNAT entity, the GCC
4350 tree node used as a dummy for that entity, if any. */
4354 /* Initialize the above table. */
4356 void
4358 {
4359 Node_Id gnat_node;
4367 }
4369 /* Make a dummy type corresponding to GNAT_TYPE. */
4371 tree
4373 {
4374 Entity_Id gnat_underlying;
4375 tree gnu_type;
4377 /* Find a full type for GNAT_TYPE, taking into account any class wide
4378 types. */
4388 ;
4390 /* If it there already a dummy type, use that one. Else make one. */
4394 /* If this is a record, make this a RECORD_TYPE or UNION_TYPE; else make
4395 it a VOID_TYPE. */
4397 {
4400 }
4403 else
4414 }
4415 \f
4416 /* Return true if the size represented by GNU_SIZE can be handled by an
4417 allocation. If STATIC_P is true, consider only what can be done with a
4418 static allocation. */
4420 static bool
4422 {
4423 HOST_WIDE_INT our_size;
4425 /* If this is not a static allocation, the only case we want to forbid
4426 is an overflowing size. That will be converted into a raise a
4427 Storage_Error. */
4432 /* Otherwise, we need to deal with both variable sizes and constant
4433 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
4434 since assemblers may not like very large sizes. */
4440 }
4441 \f
4442 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
4444 static void
4446 {
4447 Node_Id gnat_temp;
4452 {
4462 {
4464 (gnat_to_gnu
4471 (gnat_to_gnu
4472 (Expression
4475 }
4478 {
4497 }
4504 /* If we have an argument specified together with an attribute name,
4505 make it a single TREE_VALUE entry in a list of arguments, as GCC
4506 expects it. */
4509 else
4512 attr->error_point
4516 }
4517 }
4518 \f
4519 /* Get the unpadded version of a GNAT type. */
4521 tree
4523 {
4530 }
4531 \f
4532 /* Called when we need to protect a variable object using a save_expr. */
4534 tree
4536 {
4543 {
4551 }
4552 else
4554 }
4555 \f
4556 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
4557 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
4558 return the GCC tree to use for that expression. GNU_NAME is the
4559 qualification to use if an external name is appropriate and DEFINITION is
4560 nonzero if this is a definition of GNAT_ENTITY. If NEED_VALUE is nonzero,
4561 we need a result. Otherwise, we are just elaborating this for
4562 side-effects. If NEED_DEBUG is nonzero we need the symbol for debugging
4563 purposes even if it isn't needed for code generation. */
4565 static tree
4569 {
4570 tree gnu_expr;
4572 /* If we already elaborated this expression (e.g., it was involved
4573 in the definition of a private type), use the old value. */
4577 /* If we don't need a value and this is static or a discriment, we
4578 don't need to do anything. */
4585 /* Otherwise, convert this tree to its GCC equivalant. */
4586 gnu_expr
4590 /* Save the expression in case we try to elaborate this entity again. Since
4591 this is not a DECL, don't check it. Don't save if it's a discriminant. */
4596 }
4598 /* Similar, but take a GNU expression. */
4600 static tree
4604 {
4606 /* Strip any conversions to see if the expression is a readonly variable.
4607 ??? This really should remain readonly, but we have to think about
4608 the typing of the tree here. */
4613 /* In most cases, we won't see a naked FIELD_DECL here because a
4614 discriminant reference will have been replaced with a COMPONENT_REF
4615 when the type is being elaborated. However, there are some cases
4616 involving child types where we will. So convert it to a COMPONENT_REF
4617 here. We have to hope it will be at the highest level of the
4618 expression in these cases. */
4624 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
4625 that is a constant, make a variable that is initialized to contain the
4626 bound when the package containing the definition is elaborated. If
4627 this entity is defined at top level and a bound or discriminant value
4628 isn't a constant or a reference to a discriminant, replace the bound
4629 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
4630 rely here on the fact that an expression cannot contain both the
4631 discriminant and some other variable. */
4638 /* If this is a static expression or contains a discriminant, we don't
4639 need the variable for debugging (and can't elaborate anyway if a
4640 discriminant). */
4646 /* Now create the variable if we need it. */
4648 gnu_decl
4653 gnat_entity);
4655 /* We only need to use this variable if we are in global context since GCC
4656 can do the right thing in the local case. */
4661 else
4663 }
4664 \f
4665 /* Create a record type that contains a field of TYPE with a starting bit
4666 position so that it is aligned to ALIGN bits and is SIZE bytes long. */
4668 tree
4670 {
4675 place));
4684 /* The bit position is obtained by "and"ing the alignment minus 1
4685 with the two's complement of the address and multiplying
4686 by the number of bits per unit. Do all this in sizetype. */
4691 size_addr_place),
4694 bitsize_unit_node);
4696 /* Create the field, with -1 as the 'addressable' indication to avoid the
4697 creation of a bitfield. We don't need one, it would have damaging
4698 consequences on the alignment computation, and create_field_decl would
4699 make one without this special argument, for instance because of the
4700 complex position expression. */
4709 bitsize_unit_node),
4715 }
4716 \f
4717 /* TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE, with BLKmode that's
4718 being used as the field type of a packed record. See if we can rewrite it
4719 as a record that has a non-BLKmode type, which we can pack tighter. If so,
4720 return the new type. If not, return the original type. */
4722 static tree
4724 {
4727 tree old_field;
4729 /* Copy the name and flags from the old type to that of the new and set
4730 the alignment to try for an integral type. For QUAL_UNION_TYPE,
4731 also copy the size. */
4740 {
4743 }
4749 /* Now copy the fields, keeping the position and size. */
4752 {
4754 tree new_field;
4770 SET_DECL_ORIGINAL_FIELD
4779 }
4784 }
4785 \f
4786 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
4787 if needed. We have already verified that SIZE and TYPE are large enough.
4789 GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
4790 to issue a warning.
4792 IS_USER_TYPE is true if we must be sure we complete the original type.
4794 DEFINITION is true if this type is being defined.
4796 SAME_RM_SIZE is true if the RM_Size of the resulting type is to be
4797 set to its TYPE_SIZE; otherwise, it's set to the RM_Size of the original
4798 type. */
4800 tree
4804 {
4806 tree record;
4807 tree field;
4809 /* If TYPE is a padded type, see if it agrees with any size and alignment
4810 we were given. If so, return the original type. Otherwise, strip
4811 off the padding, since we will either be returning the inner type
4812 or repadding it. If no size or alignment is specified, use that of
4813 the original padded type. */
4816 {
4833 }
4835 /* If the size is either not being changed or is being made smaller (which
4836 is not done here (and is only valid for bitfields anyway), show the size
4837 isn't changing. Likewise, clear the alignment if it isn't being
4838 changed. Then return if we aren't doing anything. */
4852 /* We used to modify the record in place in some cases, but that could
4853 generate incorrect debugging information. So make a new record
4854 type and name. */
4860 /* If we were making a type, complete the original type and give it a
4861 name. */
4868 gnat_entity);
4870 /* If we are changing the alignment and the input type is a record with
4871 BLKmode and a small constant size, try to make a form that has an
4872 integral mode. That might allow this record to have an integral mode,
4873 which will be much more efficient. There is no point in doing this if a
4874 size is specified unless it is also smaller than the biggest alignment
4875 and it is incorrect to do this if the size of the original type is not a
4876 multiple of the alignment. */
4882 && (!size
4904 /* Keep the RM_Size of the padded record as that of the old record
4905 if requested. */
4908 /* Unless debugging information isn't being written for the input type,
4909 write a record that shows what we are a subtype of and also make a
4910 variable that indicates our size, if variable. */
4914 {
4935 }
4942 /* If the size was widened explicitly, maybe give a warning. */
4948 {
4961 /* Generate message only for entities that come from source, since
4962 if we have an entity created by expansion, the message will be
4963 generated for some other corresponding source entity. */
4966 gnat_entity,
4973 }
4976 }
4977 \f
4978 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
4979 the value passed against the list of choices. */
4981 tree
4983 {
4984 Node_Id choice;
4985 Node_Id gnat_temp;
4990 {
4992 {
4997 /* There's no good type to use here, so we might as well use
4998 integer_type_node. */
4999 this_test
5013 this_test
5023 /* This represents either a subtype range, an enumeration
5024 literal, or a constant Ekind says which. If an enumeration
5025 literal or constant, fall through to the next case. */
5028 {
5034 this_test
5041 }
5042 /* ... fall through ... */
5047 single);
5056 }
5060 }
5063 }
5064 \f
5065 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
5066 placed in GNU_RECORD_TYPE.
5068 PACKED is 1 if the enclosing record is packed and -1 if the enclosing
5069 record has a Component_Alignment of Storage_Unit.
5071 DEFINITION is true if this field is for a record being defined. */
5073 static tree
5076 {
5082 tree gnu_field;
5083 bool needs_strict_alignment
5087 /* If this field requires strict alignment or contains an item of
5088 variable sized, pretend it isn't packed. */
5092 /* For packed records, this is one of the few occasions on which we use
5093 the official RM size for discrete or fixed-point components, instead
5094 of the normal GNAT size stored in Esize. See description in Einfo:
5095 "Handling of Type'Size Values" for further details. */
5105 /* If the field's type is justified modular and the size of the packed
5106 array it wraps is the same as that of the field, we can make the field
5107 the type of the inner object. Note that we may need to do so if the
5108 record is packed or the field has a component clause, but these cases
5109 are handled later. */
5116 /* If we are packing this record, have a specified size that's smaller than
5117 that of the field type, or a position is specified, and the field type
5118 is also a record that's BLKmode and with a small constant size, see if
5119 we can get a better form of the type that allows more packing. If we
5120 can, show a size was specified for it if there wasn't one so we know to
5121 make this a bitfield and avoid making things wider. */
5130 {
5135 }
5137 /* If we are packing the record and the field is BLKmode, round the
5138 size up to a byte boundary. */
5143 {
5148 /* Ensure the position does not overlap with the parent subtype,
5149 if there is one. */
5151 {
5152 tree gnu_parent
5158 {
5159 post_error_ne_tree
5163 }
5164 }
5166 /* If this field needs strict alignment, ensure the record is
5167 sufficiently aligned and that that position and size are
5168 consistent with the alignment. */
5170 {
5177 /* If Atomic, the size must match exactly and if aliased, the size
5178 must not be less than the rounded size. */
5181 {
5182 post_error_ne_tree
5188 }
5192 {
5193 post_error_ne_tree
5196 gnu_min_size);
5198 }
5203 {
5205 post_error_ne_num
5211 post_error_ne_num
5217 post_error_ne_num
5221 else
5225 }
5226 }
5230 }
5232 /* If the record has rep clauses and this is the tag field, make a rep
5233 clause for it as well. */
5236 {
5239 }
5241 /* We need to make the size the maximum for the type if it is
5242 self-referential and an unconstrained type. In that case, we can't
5243 pack the field since we can't make a copy to align it. */
5245 && !gnu_size
5248 {
5251 }
5253 /* If no size is specified (or if there was an error), don't specify a
5254 position. */
5257 else
5258 {
5259 /* If the field's type is justified modular, we would need to remove
5260 the wrapper to (better) meet the layout requirements. However we
5261 can do so only if the field is not aliased to preserve the unique
5262 layout and if the prescribed size is not greater than that of the
5263 packed array to preserve the justification. */
5271 gnu_field_type
5276 }
5281 /* Now create the decl for the field. */
5293 }
5294 \f
5295 /* Return true if TYPE is a type with variable size, a padding type with a
5296 field of variable size or is a record that has a field such a field. */
5298 static bool
5300 {
5301 tree field;
5303 /* We need not be concerned about this at all if we don't have
5304 strict alignment. */
5322 }
5323 \f
5324 /* Return a GCC tree for a record type given a GNAT Component_List and a chain
5325 of GCC trees for fields that are in the record and have already been
5326 processed. When called from gnat_to_gnu_entity during the processing of a
5327 record type definition, the GCC nodes for the discriminants will be on
5328 the chain. The other calls to this function are recursive calls from
5329 itself for the Component_List of a variant and the chain is empty.
5331 PACKED is 1 if this is for a record with "pragma pack" and -1 is this is
5332 for a record type with "pragma component_alignment (storage_unit)".
5334 DEFINITION is true if we are defining this record.
5336 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
5337 with a rep clause is to be added. If it is nonzero, that is all that
5338 should be done with such fields.
5340 CANCEL_ALIGNMENT, if true, means the alignment should be zeroed before
5341 laying out the record. This means the alignment only serves to force fields
5342 to be bitfields, but not require the record to be that aligned. This is
5343 used for variants.
5345 ALL_REP, if true, means a rep clause was found for all the fields. This
5346 simplifies the logic since we know we're not in the mixed case.
5348 The processing of the component list fills in the chain with all of the
5349 fields of the record and then the record type is finished. */
5351 static void
5356 {
5357 Node_Id component_decl;
5358 Entity_Id gnat_field;
5359 Node_Id variant_part;
5360 Node_Id variant;
5366 /* For each variable within each component declaration create a GCC field
5367 and add it to the list, skipping any pragmas in the list. */
5373 {
5378 else
5379 {
5383 /* If this is the _Tag field, put it before any discriminants,
5384 instead of after them as is the case for all other fields.
5385 Ignore field of void type if only annotating. */
5388 else
5389 {
5392 }
5393 }
5396 }
5398 /* At the end of the component list there may be a variant part. */
5401 /* If this is an unchecked union, each variant must have exactly one
5402 component, each of which becomes one component of this union. */
5409 {
5410 component_decl
5414 definition);
5418 }
5420 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
5421 mutually exclusive and should go in the same memory. To do this we need
5422 to treat each variant as a record whose elements are created from the
5423 component list for the variant. So here we create the records from the
5424 lists for the variants and put them all into the QUAL_UNION_TYPE. */
5426 {
5428 Node_Id variant;
5430 tree gnu_union_field;
5433 tree gnu_var_name
5434 = concat_id_with_name
5448 {
5450 tree gnu_inner_name;
5451 tree gnu_qual;
5459 /* Set the alignment of the inner type in case we need to make
5460 inner objects into bitfields, but then clear it out
5461 so the record actually gets only the alignment required. */
5465 /* Similarly, if the outer record has a size specified and all fields
5466 have record rep clauses, we can propagate the size into the
5467 variant part. */
5469 {
5473 }
5485 (all_rep_and_size
5487 (all_rep_and_size
5495 }
5497 /* We use to delete the empty variants from the end. However,
5498 we no longer do that because we need them to generate complete
5499 debugging information for the variant record. Otherwise,
5500 the union type definition will be missing the fields associated
5501 to these empty variants. */
5503 /* Only make the QUAL_UNION_TYPE if there are any non-empty variants. */
5505 {
5507 {
5511 }
5516 gnu_union_field
5518 packed,
5525 }
5526 }
5528 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
5529 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do this
5530 in a separate pass since we want to handle the discriminants but can't
5531 play with them until we've used them in debugging data above.
5533 ??? Note: if we then reorder them, debugging information will be wrong,
5534 but there's nothing that can be done about this at the moment. */
5537 {
5539 {
5544 else
5550 }
5551 else
5552 {
5555 }
5556 }
5558 /* If we have any items in our rep'ed field list, it is not the case that all
5559 the fields in the record have rep clauses, and P_REP_LIST is nonzero,
5560 set it and ignore the items. Otherwise, sort the fields by bit position
5561 and put them into their own record if we have any fields without
5562 rep clauses. */
5566 {
5567 tree gnu_rep_type
5573 /* Set DECL_SECTION_NAME to increasing integers so we have a
5574 stable sort. */
5577 {
5580 }
5584 /* Put the fields in the list in order of increasing position, which
5585 means we start from the end. */
5588 {
5593 }
5596 {
5602 }
5603 else
5604 {
5607 }
5608 }
5615 }
5616 \f
5617 /* Called via qsort from the above. Returns -1, 1, depending on the
5618 bit positions and ordinals of the two fields. */
5620 static int
5622 {
5627 return
5632 else
5634 }
5635 \f
5636 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
5637 placed into an Esize, Component_Bit_Offset, or Component_Size value
5638 in the GNAT tree. */
5640 static Uint
5642 {
5644 TCode tcode;
5649 /* If back annotation is suppressed by the front end, return No_Uint */
5653 /* See if we've already saved the value for this node. */
5657 /* If we do not return inside this switch, TCODE will be set to the
5658 code to use for a Create_Node operand and LEN (set above) will be
5659 the number of recursive calls for us to make. */
5662 {
5667 /* This may have come from a conversion from some smaller type,
5668 so ensure this is in bitsizetype. */
5671 /* For negative values, use NEGATE_EXPR of the supplied value. */
5673 {
5674 /* The rediculous code below is to handle the case of the largest
5675 negative integer. */
5678 tree temp;
5681 {
5682 negative_size
5685 bitsize_one_node));
5687 }
5694 }
5701 /* This peculiar test is to make sure that the size fits in an int
5702 on machines where HOST_WIDE_INT is not "int". */
5705 else
5709 /* The only case we handle here is a simple discriminant reference. */
5717 else
5723 /* Now just list the operations we handle. */
5754 }
5756 /* Now get each of the operands that's relevant for this code. If any
5757 cannot be expressed as a repinfo node, say we can't. */
5762 {
5766 }
5771 }
5773 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding
5774 GCC type, set Component_Bit_Offset and Esize to the position and size
5775 used by Gigi. */
5777 static void
5779 {
5780 tree gnu_list;
5781 tree gnu_entry;
5782 Entity_Id gnat_field;
5784 /* We operate by first making a list of all field and their positions
5785 (we can get the sizes easily at any time) by a recursive call
5786 and then update all the sizes into the tree. */
5789 BIGGEST_ALIGNMENT);
5796 {
5799 gnu_entry
5801 gnu_list);
5804 {
5806 {
5807 /* In this mode the tag and parent components have not been
5808 generated, so we add the appropriate offset to each
5809 component. For a component appearing in the current
5810 extension, the offset is the size of the parent. */
5813 parent_offset
5815 bitsizetype);
5816 else
5818 }
5820 Set_Component_Bit_Offset
5822 annotate_value
5827 parent_offset)));
5831 }
5835 {
5836 /* If there is no gnu_entry, this is an inherited component whose
5837 position is the same as in the parent type. */
5838 Set_Component_Bit_Offset
5843 }
5844 }
5845 }
5847 /* Scan all fields in GNU_TYPE and build entries where TREE_PURPOSE is the
5848 FIELD_DECL and TREE_VALUE a TREE_LIST with TREE_PURPOSE being the byte
5849 position and TREE_VALUE being a TREE_LIST with TREE_PURPOSE the value to be
5850 placed into DECL_OFFSET_ALIGN and TREE_VALUE the bit position. GNU_POS is
5851 to be added to the position, GNU_BITPOS to the bit position, OFFSET_ALIGN is
5852 the present value of DECL_OFFSET_ALIGN and GNU_LIST is a list of the entries
5853 so far. */
5855 static tree
5858 {
5859 tree gnu_field;
5864 {
5869 unsigned int our_offset_align
5872 gnu_result
5877 NULL_TREE),
5878 gnu_result);
5881 gnu_result
5884 our_offset_align);
5885 }
5888 }
5889 \f
5890 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
5891 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
5892 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
5893 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
5894 for the size of a field. COMPONENT_P is true if we are being called
5895 to process the Component_Size of GNAT_OBJECT. This is used for error
5896 message handling and to indicate to use the object size of GNU_TYPE.
5897 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
5898 it means that a size of zero should be treated as an unspecified size. */
5900 static tree
5903 {
5904 Node_Id gnat_error_node;
5905 tree type_size
5907 tree size;
5909 /* Find the node to use for errors. */
5916 else
5919 /* Return 0 if no size was specified, either because Esize was not Present or
5920 the specified size was zero. */
5924 /* Get the size as a tree. Give an error if a size was specified, but cannot
5925 be represented as in sizetype. */
5928 {
5933 }
5935 /* Ignore a negative size since that corresponds to our back-annotation.
5936 Also ignore a zero size unless a size clause exists. */
5940 /* The size of objects is always a multiple of a byte. */
5943 {
5947 else
5951 }
5953 /* If this is an integral type or a packed array type, the front-end has
5954 verified the size, so we need not do it here (which would entail
5955 checking against the bounds). However, if this is an aliased object, it
5956 may not be smaller than the type of the object. */
5961 /* If the object is a record that contains a template, add the size of
5962 the template to the specified size. */
5967 /* Modify the size of the type to be that of the maximum size if it has a
5968 discriminant or the size of a thin pointer if this is a fat pointer. */
5974 /* If this is an access type, the minimum size is that given by the smallest
5975 integral mode that's valid for pointers. */
5977 {
5983 ;
5986 }
5988 /* If the size of the object is a constant, the new size must not be
5989 smaller. */
5993 {
5995 post_error_ne_tree
5998 else
6005 post_error_ne_tree_2
6015 }
6018 }
6019 \f
6020 /* Similarly, but both validate and process a value of RM_Size. This
6021 routine is only called for types. */
6023 static void
6025 {
6026 /* Only give an error if a Value_Size clause was explicitly given.
6027 Otherwise, we'd be duplicating an error on the Size clause. */
6028 Node_Id gnat_attr_node
6031 tree size;
6033 /* Get the size as a tree. Do nothing if none was specified, either
6034 because RM_Size was not Present or if the specified size was zero.
6035 Give an error if a size was specified, but cannot be represented as
6036 in sizetype. */
6042 {
6045 gnat_entity);
6048 }
6050 /* Ignore a negative size since that corresponds to our back-annotation.
6051 Also ignore a zero size unless a size clause exists, a Value_Size
6052 clause exists, or this is an integer type, in which case the
6053 front end will have always set it. */
6060 /* If the old size is self-referential, get the maximum size. */
6064 /* If the size of the object is a constant, the new size must not be
6065 smaller (the front end checks this for scalar types). */
6070 {
6072 post_error_ne_tree
6077 }
6079 /* Otherwise, set the RM_Size. */
6090 }
6091 \f
6092 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
6093 If TYPE is the best type, return it. Otherwise, make a new type. We
6094 only support new integral and pointer types. BIASED_P is nonzero if
6095 we are making a biased type. */
6097 static tree
6099 {
6100 tree new_type;
6104 /* If size indicates an error, just return TYPE to avoid propagating the
6105 error. Likewise if it's too large to represent. */
6111 {
6114 /* Only do something if the type is not already the proper size and is
6115 not a packed array type. */
6127 new_type
6139 /* Do something if this is a fat pointer, in which case we
6140 may need to return the thin pointer. */
6142 return
6143 build_pointer_type
6148 /* Only do something if this is a thin pointer, in which case we
6149 may need to return the fat pointer. */
6151 return
6158 }
6161 }
6162 \f
6163 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
6164 a type or object whose present alignment is ALIGN. If this alignment is
6165 valid, return it. Otherwise, give an error and return ALIGN. */
6167 static unsigned int
6169 {
6173 #ifndef MAX_OFILE_ALIGNMENT
6174 #define MAX_OFILE_ALIGNMENT BIGGEST_ALIGNMENT
6175 #endif
6180 /* Don't worry about checking alignment if alignment was not specified
6181 by the source program and we already posted an error for this entity. */
6186 /* Within GCC, an alignment is an integer, so we must make sure a
6187 value is specified that fits in that range. Also, alignments of
6188 more than MAX_OFILE_ALIGNMENT can't be supported. */
6202 else
6206 }
6207 \f
6208 /* Verify that OBJECT, a type or decl, is something we can implement
6209 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
6210 if we require atomic components. */
6212 static void
6214 {
6216 Node_Id gnat_node;
6219 tree size;
6221 /* There are three case of what OBJECT can be. It can be a type, in which
6222 case we take the size, alignment and mode from the type. It can be a
6223 declaration that was indirect, in which case the relevant values are
6224 that of the type being pointed to, or it can be a normal declaration,
6225 in which case the values are of the decl. The code below assumes that
6226 OBJECT is either a type or a decl. */
6228 {
6232 }
6234 {
6238 }
6239 else
6240 {
6244 }
6246 /* Consider all floating-point types atomic and any types that that are
6247 represented by integers no wider than a machine word. */
6254 /* For the moment, also allow anything that has an alignment equal
6255 to its size and which is smaller than a word. */
6263 {
6271 }
6276 else
6279 }
6280 \f
6281 /* Check if FTYPE1 and FTYPE2, two potentially different function type nodes,
6282 have compatible signatures so that a call using one type may be safely
6283 issued if the actual target function type is the other. Return 1 if it is
6284 the case, 0 otherwise, and post errors on the incompatibilities.
6286 This is used when an Ada subprogram is mapped onto a GCC builtin, to ensure
6287 that calls to the subprogram will have arguments suitable for the later
6288 underlying builtin expansion. */
6290 static int
6292 {
6293 /* As of now, we only perform very trivial tests and consider it's the
6294 programmer's responsability to ensure the type correctness in the Ada
6295 declaration, as in the regular Import cases.
6297 Mismatches typically result in either error messages from the builtin
6298 expander, internal compiler errors, or in a real call sequence. This
6299 should be refined to issue diagnostics helping error detection and
6300 correction. */
6302 /* Almost fake test, ensuring a use of each argument. */
6307 }
6308 \f
6309 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new type
6310 with all size expressions that contain F updated by replacing F with R.
6311 This is identical to GCC's substitute_in_type except that it knows about
6312 TYPE_INDEX_TYPE. If F is NULL_TREE, always make a new RECORD_TYPE, even if
6313 nothing has changed. */
6315 tree
6317 {
6319 tree tem;
6322 {
6329 {
6338 SET_TYPE_INDEX_TYPE
6341 }
6348 {
6362 }
6377 /* Don't know how to do these yet. */
6381 {
6395 /* If we had bounded the sizes of T by a constant, bound the sizes of
6396 NEW by the same constant. */
6406 }
6411 {
6412 tree field;
6413 bool changed_field
6420 /* Start out with no fields, make new fields, and chain them
6421 in. If we haven't actually changed the type of any field,
6422 discard everything we've done and return the old type. */
6428 {
6439 /* If this is an internal field and the type of this field is
6440 a UNION_TYPE or RECORD_TYPE with no elements, ignore it. If
6441 the type just has one element, treat that as the field.
6442 But don't do this if we are processing a QUAL_UNION_TYPE. */
6447 {
6452 {
6453 tree next_new_field
6456 /* Make sure omitting the union doesn't change
6457 the layout. */
6460 }
6461 }
6468 /* If the size of the old field was set at a constant,
6469 propagate the size in case the type's size was variable.
6470 (This occurs in the case of a variant or discriminated
6471 record with a default size used as a field of another
6472 record.) */
6481 {
6487 /* Do the substitution inside the qualifier and if we find
6488 that this field will not be present, omit it. */
6493 }
6497 else
6502 /* If this is a qualified type and this field will always be
6503 present, we are done. */
6507 }
6509 /* If this used to be a qualified union type, but we now know what
6510 field will be present, make this a normal union. */
6521 /* If the size was originally a constant use it. */
6524 {
6528 }
6531 }
6535 }
6536 }
6537 \f
6538 /* Return the "RM size" of GNU_TYPE. This is the actual number of bits
6539 needed to represent the object. */
6541 tree
6543 {
6544 /* For integer types, this is the precision. For record types, we store
6545 the size explicitly. For other types, this is just the size. */
6551 /* Return the rm_size of the actual data plus the size of the template. */
6552 return
6562 else
6564 }
6565 \f
6566 /* Return an identifier representing the external name to be used for
6567 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
6568 and the specified suffix. */
6570 tree
6572 {
6579 #ifdef _WIN32
6580 /* A variable using the Stdcall convention (meaning we are running
6581 on a Windows box) live in a DLL. Here we adjust its name to use
6582 the jump-table, the _imp__NAME contains the address for the NAME
6583 variable. */
6584 {
6591 {
6596 }
6597 }
6598 #endif
6601 }
6603 /* Return the name to be used for GNAT_ENTITY. If a type, create a
6604 fully-qualified name, possibly with type information encoding.
6605 Otherwise, return the name. */
6607 tree
6609 {
6612 }
6614 /* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
6615 string, return a new IDENTIFIER_NODE that is the concatenation of
6616 the name in GNU_ID and SUFFIX. */
6618 tree
6620 {
6629 }