| blob | 710d0f1a4f07e00ec4e3cdb3fc1625cf25a6b198 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2004, 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 }
755 ;
757 /* If this is a declaration or reference that we can stabilize,
758 just use that declaration or reference as this entity unless
759 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 {
798 }
802 }
803 }
805 /* If this is an aliased object whose nominal subtype is unconstrained,
806 the object is a record that contains both the template and
807 the object. If there is an initializer, it will have already
808 been converted to the right type, but we need to create the
809 template if there is no initializer. */
812 /* Beware that padding might have been introduced
813 via maybe_pad_type above. */
816 == RECORD_TYPE
817 && TYPE_CONTAINS_TEMPLATE_P
820 {
821 tree template_field
826 gnu_expr
827 = gnat_build_constructor
829 tree_cons
833 NULL_TREE),
834 NULL_TREE));
835 }
837 /* If this is a pointer and it does not have an initializing
838 expression, initialize it to NULL, unless the obect is
839 imported. */
845 /* If we are defining the object and it has an Address clause we must
846 get the address expression from the saved GCC tree for the
847 object if the object has a Freeze_Node. Otherwise, we elaborate
848 the address expression here since the front-end has guaranteed
849 in that case that the elaboration has no effects. Note that
850 only the latter mechanism is currently in use. */
852 {
853 tree gnu_address
859 /* Ignore the size. It's either meaningless or was handled
860 above. */
867 /* If we don't have an initializing expression for the underlying
868 variable, the initializing expression for the pointer is the
869 specified address. Otherwise, we have to make a COMPOUND_EXPR
870 to assign both the address and the initial value. */
873 else
874 gnu_expr
876 build_binary_op
879 gnu_address),
880 gnu_expr),
881 gnu_address);
882 }
884 /* If it has an address clause and we are not defining it, mark it
885 as an indirect object. Likewise for Stdcall objects that are
886 imported. */
890 {
894 }
896 /* If we are at top level and this object is of variable size,
897 make the actual type a hidden pointer to the real type and
898 make the initializer be a memory allocation and initialization.
899 Likewise for objects we aren't defining (presumed to be
900 external references from other packages), but there we do
901 not set up an initialization.
903 If the object's size overflows, make an allocator too, so that
904 Storage_Error gets raised. Note that we will never free
905 such memory, so we presume it never will get allocated. */
910 || (gnu_size
914 {
920 /* In case this was a aliased object whose nominal subtype is
921 unconstrained, the pointer above will be a thin pointer and
922 build_allocator will automatically make the template.
924 If we have a template initializer only (that we made above),
925 pretend there is none and rely on what build_allocator creates
926 again anyway. Otherwise (if we have a full initializer), get
927 the data part and feed that to build_allocator. */
930 {
935 {
936 gnu_alloc_type
940 &&
943 else
944 gnu_expr
945 = build_component_ref
949 }
955 gnat_entity);
959 }
960 else
961 {
964 }
965 }
967 /* If this object would go into the stack and has an alignment
968 larger than the default largest alignment, make a variable
969 to hold the "aligning type" with a modified initial value,
970 if any, then point to it and make that the value of this
971 variable, which is now indirect. */
974 {
975 tree gnu_new_type
978 tree gnu_new_var;
980 gnu_new_var
986 add_stmt_with_node
988 build_component_ref
991 gnu_expr),
992 gnat_entity);
995 gnu_expr
996 = build_unary_op
1004 }
1006 /* Convert the expression to the type of the object except in the
1007 case where the object's type is unconstrained or the object's type
1008 is a padded record whose field is of self-referential size. In
1009 the former case, converting will generate unnecessary evaluations
1010 of the CONSTRUCTOR to compute the size and in the latter case, we
1011 want to only copy the actual data. */
1017 && (CONTAINS_PLACEHOLDER_P
1021 /* If this name is external or there was a name specified, use it,
1022 unless this is a VMS exception object since this would conflict
1023 with the symbol we need to export in addition. Don't use the
1024 Interface_Name if there is an address clause (see CD30005). */
1034 {
1039 }
1041 /* If this is constant initialized to a static constant and the
1042 object has an aggregrate type, force it to be statically
1043 allocated. */
1059 /* If we have an address clause and we've made this indirect, it's
1060 not enough to merely mark the type as volatile since volatile
1061 references only conflict with other volatile references while this
1062 reference must conflict with all other references. So ensure that
1063 the dereferenced value has alias set 0. */
1072 STACK_CHECK_MAX_VAR_SIZE))))
1077 gnat_entity);
1079 /* If this is a public constant or we're not optimizing and we're not
1080 making a VAR_DECL for it, make one just for export or debugger
1081 use. Likewise if the address is taken or if the object or type is
1082 aliased. */
1089 {
1090 tree gnu_corr_var
1096 }
1098 /* If this is declared in a block that contains an block with an
1099 exception handler, we must force this variable in memory to
1100 suppress an invalid optimization. */
1105 /* Back-annotate the Alignment of the object if not already in the
1106 tree. Likewise for Esize if the object is of a constant size.
1107 But if the "object" is actually a pointer to an object, the
1108 alignment and size are the same as teh type, so don't back-annotate
1109 the values for the pointer. */
1116 {
1121 gnu_back_size
1126 }
1127 }
1131 /* Return a TYPE_DECL for "void" that we previously made. */
1136 /* A special case, for the types Character and Wide_Character in
1137 Standard, we do not list all the literals. So if the literals
1138 are not specified, make this an unsigned type. */
1140 {
1143 }
1145 /* Normal case of non-character type, or non-Standard character type */
1146 {
1147 /* Here we have a list of enumeral constants in First_Literal.
1148 We make a CONST_DECL for each and build into GNU_LITERAL_LIST
1149 the list to be places into TYPE_FIELDS. Each node in the list
1150 is a TREE_LIST node whose TREE_VALUE is the literal name
1151 and whose TREE_PURPOSE is the value of the literal.
1153 Esize contains the number of bits needed to represent the enumeral
1154 type, Type_Low_Bound also points to the first literal and
1155 Type_High_Bound points to the last literal. */
1157 Entity_Id gnat_literal;
1162 else
1170 {
1172 gnu_type);
1173 tree gnu_literal
1181 }
1185 /* Note that the bounds are updated at the end of this function
1186 because to avoid an infinite recursion when we get the bounds of
1187 this type, since those bounds are objects of this type. */
1188 }
1194 /* For integer types, just make a signed type the appropriate number
1195 of bits. */
1200 /* For modular types, make the unsigned type of the proper number of
1201 bits and then set up the modulus, if required. */
1202 {
1204 tree gnu_modulus;
1210 /* Find the smallest mode at least ESIZE bits wide and make a class
1211 using that mode. */
1216 ;
1222 /* Get the modulus in this type. If it overflows, assume it is because
1223 it is equal to 2**Esize. Note that there is no overflow checking
1224 done on unsigned type, so we detect the overflow by looking for
1225 a modulus of zero, which is otherwise invalid. */
1229 {
1234 }
1236 /* If we have to set TYPE_PRECISION different from its natural value,
1237 make a subtype to do do. Likewise if there is a modulus and
1238 it is not one greater than TYPE_MAX_VALUE. */
1242 {
1259 }
1260 }
1269 /* For integral subtypes, we make a new INTEGER_TYPE. Note
1270 that we do not want to call build_range_type since we would
1271 like each subtype node to be distinct. This will be important
1272 when memory aliasing is implemented.
1274 The TREE_TYPE field of the INTEGER_TYPE we make points to the
1275 parent type; this fact is used by the arithmetic conversion
1276 functions.
1278 We elaborate the Ancestor_Subtype if it is not in the current
1279 unit and one of our bounds is non-static. We do this to ensure
1280 consistent naming in the case where several subtypes share the same
1281 bounds by always elaborating the first such subtype first, thus
1282 using its name. */
1294 {
1297 }
1305 gnat_entity,
1312 gnat_entity,
1316 /* One of the above calls might have caused us to be elaborated,
1317 so don't blow up if so. */
1319 {
1322 }
1327 /* This should be an unsigned type if the lower bound is constant
1328 and non-negative or if the base type is unsigned; a signed type
1329 otherwise. */
1339 /* If the type we are dealing with is to represent a packed array,
1340 we need to have the bits left justified on big-endian targets
1341 and right justified on little-endian targets. We also need to
1342 ensure that when the value is read (e.g. for comparison of two
1343 such values), we only get the good bits, since the unused bits
1344 are uninitialized. Both goals are accomplished by wrapping the
1345 modular value in an enclosing struct. */
1347 {
1349 tree gnu_field;
1358 /* Create a stripped-down declaration of the original type, mainly
1359 for debugging. */
1363 /* Don't notify the field as "addressable", since we won't be taking
1364 it's address and it would prevent create_field_decl from making a
1365 bitfield. */
1372 }
1377 /* If this is a VAX floating-point type, use an integer of the proper
1378 size. All the operations will be handled with ASM statements. */
1380 {
1385 sizetype));
1387 }
1389 /* The type of the Low and High bounds can be our type if this is
1390 a type from Standard, so set them at the end of the function. */
1398 {
1401 }
1403 {
1430 /* One of the above calls might have caused us to be elaborated,
1431 so don't blow up if so. */
1433 {
1436 }
1439 }
1442 /* Array and String Types and Subtypes
1444 Unconstrained array types are represented by E_Array_Type and
1445 constrained array types are represented by E_Array_Subtype. There
1446 are no actual objects of an unconstrained array type; all we have
1447 are pointers to that type.
1449 The following fields are defined on array types and subtypes:
1451 Component_Type Component type of the array.
1452 Number_Dimensions Number of dimensions (an int).
1453 First_Index Type of first index. */
1457 {
1463 int firstdim
1465 int nextdim
1471 tree gnu_max_size_unit;
1473 Entity_Id gnat_ind_subtype;
1474 Entity_Id gnat_ind_base_subtype;
1475 tree gnu_template_reference;
1476 tree tem;
1484 /* Make a node for the array. If we are not defining the array
1485 suppress expanding incomplete types and save the node as the type
1486 for GNAT_ENTITY. */
1489 {
1490 defer_incomplete_level++;
1497 }
1499 /* Build the fat pointer type. Use a "void *" object instead of
1500 a pointer to the array type since we don't have the array type
1501 yet (it will reference the fat pointer via the bounds). */
1504 ptr_void_type_node,
1507 gnu_ptr_template,
1510 /* Make sure we can put this into a register. */
1514 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1515 is the fat pointer. This will be used to access the individual
1516 fields once we build them. */
1520 gnu_template_reference
1524 /* Now create the GCC type for each index and add the fields for
1525 that index to the template. */
1527 gnat_ind_base_subtype
1533 {
1535 tree gnu_ind_subtype
1537 tree gnu_base_subtype
1539 tree gnu_base_min
1541 tree gnu_base_max
1545 /* Make the FIELD_DECLs for the minimum and maximum of this
1546 type and then make extractions of that field from the
1547 template. */
1550 gnu_ind_subtype,
1554 gnu_ind_subtype,
1563 /* We can't use build_component_ref here since the template
1564 type isn't complete yet. */
1567 NULL_TREE);
1570 NULL_TREE);
1573 /* Make a range type with the new ranges, but using
1574 the Ada subtype. Then we convert to sizetype. */
1580 /* Update the maximum size of the array, in elements. */
1581 gnu_max_size
1585 gnu_base_min)));
1589 }
1592 gnu_template_fields
1595 /* Install all the fields into the template. */
1600 /* Now make the array of arrays and update the pointer to the array
1601 in the fat pointer. Note that it is the first field. */
1605 /* Get and validate any specified Component_Size, but if Packed,
1606 ignore it since the front end will have taken care of it. */
1607 gnu_comp_size
1609 gnat_entity,
1617 /* If the component type is a RECORD_TYPE that has a self-referential
1618 size, use the maxium size. */
1624 {
1628 }
1634 /* If Component_Size is not already specified, annotate it with the
1635 size of the component. */
1645 gnu_max_size),
1649 {
1653 /* If the type below this an multi-array type, then this
1654 does not not have aliased components.
1656 ??? Otherwise, for now, we say that any component of aggregate
1657 type is addressable because the front end may take 'Reference
1658 of it. But we have to make it addressable if it must be passed
1659 by reference or it that is the default. */
1665 }
1667 /* If an alignment is specified, use it if valid. But ignore it for
1668 types that represent the unpacked base type for packed arrays. */
1671 {
1676 }
1682 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
1683 corresponding fat pointer. */
1690 /* If the maximum size doesn't overflow, use it. */
1705 /* Create a record type for the object and its template and
1706 set the template at a negative offset. */
1718 /* Give the thin pointer type a name. */
1722 gnat_entity);
1723 }
1729 /* This is the actual data type for array variables. Multidimensional
1730 arrays are implemented in the gnu tree as arrays of arrays. Note
1731 that for the moment arrays which have sparse enumeration subtypes as
1732 index components create sparse arrays, which is obviously space
1733 inefficient but so much easier to code for now.
1735 Also note that the subtype never refers to the unconstrained
1736 array type, which is somewhat at variance with Ada semantics.
1738 First check to see if this is simply a renaming of the array
1739 type. If so, the result is the array type. */
1744 else
1745 {
1748 int first_dim
1751 int next_dim
1753 Entity_Id gnat_ind_subtype;
1754 Entity_Id gnat_ind_base_subtype;
1759 tree gnu_max_size_unit;
1763 /* First create the gnu types for each index. Create types for
1764 debugging information to point to the index types if the
1765 are not integer types, have variable bounds, or are
1766 wider than sizetype. */
1769 gnat_ind_base_subtype
1775 {
1776 tree gnu_index_subtype
1778 tree gnu_min
1780 tree gnu_max
1782 tree gnu_base_subtype
1784 tree gnu_base_min
1786 tree gnu_base_max
1789 tree gnu_base_base_min
1791 tree gnu_base_base_max
1793 tree gnu_high;
1794 tree gnu_this_max;
1796 /* If the minimum and maximum values both overflow in
1797 SIZETYPE, but the difference in the original type
1798 does not overflow in SIZETYPE, ignore the overflow
1799 indications. */
1807 && (!TREE_OVERFLOW
1815 /* Similarly, if the range is null, use bounds of 1..0 for
1816 the sizetype bounds. */
1828 /* Now compute the size of this bound. We need to provide
1829 GCC with an upper bound to use but have to deal with the
1830 "superflat" case. There are three ways to do this. If we
1831 can prove that the array can never be superflat, we can
1832 just use the high bound of the index subtype. If we can
1833 prove that the low bound minus one can't overflow, we
1834 can do this as MAX (hb, lb - 1). Otherwise, we have to use
1835 the expression hb >= lb ? hb : lb - 1. */
1838 /* See if the base array type is already flat. If it is, we
1839 are probably compiling an ACVC test, but it will cause the
1840 code below to malfunction if we don't handle it specially. */
1848 /* If gnu_high is now an integer which overflowed, the array
1849 cannot be superflat. */
1856 else
1857 gnu_high
1858 = build_cond_expr
1866 /* Also compute the maximum size of the array. Here we
1867 see if any constraint on the index type of the base type
1868 can be used in the case of self-referential bound on
1869 the index type of the subtype. We look for a non-"infinite"
1870 and non-self-referential bound from any type involved and
1871 handle each bound separately. */
1896 gnu_this_max
1900 gnu_base_min)),
1901 size_zero_node);
1907 gnu_max_size
1921 }
1923 /* Then flatten: create the array of arrays. */
1927 /* One of the above calls might have caused us to be elaborated,
1928 so don't blow up if so. */
1930 {
1933 }
1935 /* Get and validate any specified Component_Size, but if Packed,
1936 ignore it since the front end will have taken care of it. */
1937 gnu_comp_size
1939 gnat_entity,
1944 /* If the component type is a RECORD_TYPE that has a self-referential
1945 size, use the maxium size. */
1951 {
1956 }
1970 {
1973 /* If the type below this an multi-array type, then this
1974 does not not have aliased components.
1976 ??? Otherwise, for now, we say that any component of aggregate
1977 type is addressable because the front end may take 'Reference
1978 of it. But we have to make it addressable if it must be passed
1979 by reference or it that is the default. */
1985 }
1987 /* If we are at file level and this is a multi-dimensional array, we
1988 need to make a variable corresponding to the stride of the
1989 inner dimensions. */
1991 {
1993 tree gnu_arr_type;
1999 {
2007 /* ??? For now, store the size as a multiple of the
2008 alignment of the element type in bytes so that we
2009 can see the alignment from the tree. */
2011 = build_binary_op
2013 elaborate_expression_1
2022 }
2023 }
2025 /* If we need to write out a record type giving the names of
2026 the bounds, do it now. */
2028 {
2031 tree gnu_field;
2037 {
2038 tree gnu_type_name
2045 integer_type_node,
2046 gnu_bound_rec_type,
2050 }
2054 }
2061 /* If our size depends on a placeholder and the maximum size doesn't
2062 overflow, use it. */
2069 {
2075 }
2077 /* Set our alias set to that of our base type. This gives all
2078 array subtypes the same alias set. */
2080 }
2082 /* If this is a packed type, make this type the same as the packed
2083 array type, but do some adjusting in the type first. */
2086 {
2087 Entity_Id gnat_index;
2088 tree gnu_inner_type;
2090 /* First finish the type we had been making so that we output
2091 debugging information for it */
2092 gnu_type
2095 | (TYPE_QUAL_VOLATILE
2103 /* Save it as our equivalent in case the call below elaborates
2104 this type again. */
2118 /* We need to point the type we just made to our index type so
2119 the actual bounds can be put into a template. */
2125 {
2127 {
2128 /* The TYPE_ACTUAL_BOUNDS field is also used for the modulus.
2129 If it is, we need to make another type. */
2131 {
2132 tree gnu_subtype;
2149 }
2152 }
2158 SET_TYPE_ACTUAL_BOUNDS
2165 SET_TYPE_ACTUAL_BOUNDS
2172 }
2173 }
2175 /* Abort if packed array with no packed array type field set. */
2176 else
2182 /* Create the type for a string literal. */
2183 {
2184 Entity_Id gnat_full_type
2189 tree gnu_string_array_type
2191 tree gnu_string_index_type
2194 tree gnu_lower_bound
2199 tree gnu_upper_bound
2201 gnu_lower_bound,
2203 tree gnu_range_type
2206 tree gnu_index_type
2211 gnu_range_type);
2213 gnu_type
2215 gnu_index_type);
2216 }
2219 /* Record Types and Subtypes
2221 The following fields are defined on record types:
2223 Has_Discriminants True if the record has discriminants
2224 First_Discriminant Points to head of list of discriminants
2225 First_Entity Points to head of list of fields
2226 Is_Tagged_Type True if the record is tagged
2228 Implementation of Ada records and discriminated records:
2230 A record type definition is transformed into the equivalent of a C
2231 struct definition. The fields that are the discriminants which are
2232 found in the Full_Type_Declaration node and the elements of the
2233 Component_List found in the Record_Type_Definition node. The
2234 Component_List can be a recursive structure since each Variant of
2235 the Variant_Part of the Component_List has a Component_List.
2237 Processing of a record type definition comprises starting the list of
2238 field declarations here from the discriminants and the calling the
2239 function components_to_record to add the rest of the fields from the
2240 component list and return the gnu type node. The function
2241 components_to_record will call itself recursively as it traverses
2242 the tree. */
2246 {
2247 gnu_type
2248 = build_complex_type
2249 (get_unpadded_type
2252 (Component_List
2253 (Type_Definition
2257 }
2259 {
2262 Entity_Id gnat_field;
2263 tree gnu_field;
2265 tree gnu_get_parent;
2272 bool is_extension
2276 /* See if all fields have a rep clause. Stop when we find one
2277 that doesn't. */
2286 /* If this is a record extension, go a level further to find the
2287 record definition. Also, verify we have a Parent_Subtype. */
2289 {
2296 }
2298 /* Make a node for the record. If we are not defining the record,
2299 suppress expanding incomplete types and save the node as the type
2300 for GNAT_ENTITY. We use the same RECORD_TYPE as for a dummy type
2301 and reset TYPE_DUMMY_P to show it's no longer a dummy.
2303 It is very tempting to delay resetting this bit until we are done
2304 with completing the type, e.g. to let possible intermediate
2305 elaboration of access types designating the record know it is not
2306 complete and arrange for update_pointer_to to fix things up later.
2308 It would be wrong, however, because dummy types are expected only
2309 to be created for Ada incomplete or private types, which is not
2310 what we have here. Doing so would make other parts of gigi think
2311 we are dealing with a really incomplete or private type, and have
2312 nasty side effects, typically on the generation of the associated
2313 debugging information. */
2324 {
2325 defer_incomplete_level++;
2332 }
2334 /* If both a size and rep clause was specified, put the size in
2335 the record type now so that it can get the proper mode. */
2339 /* Always set the alignment here so that it can be used to
2340 set the mode, if it is making the alignment stricter. If
2341 it is invalid, it will be checked again below. If this is to
2342 be Atomic, choose a default alignment of a word unless we know
2343 the size and it's smaller. */
2352 /* If we have a Parent_Subtype, make a field for the parent. If
2353 this record has rep clauses, force the position to zero. */
2355 {
2356 tree gnu_parent;
2358 /* A major complexity here is that the parent subtype will
2359 reference our discriminants. But those must reference
2360 the parent component of this record. So here we will
2361 initialize each of those components to a COMPONENT_REF.
2362 The first operand of that COMPONENT_REF is another
2363 COMPONENT_REF which will be filled in below, once
2364 the parent type can be safely built. */
2369 NULL_TREE),
2370 NULL_TREE);
2377 save_gnu_tree
2381 gnu_get_parent,
2385 NULL_TREE),
2390 gnu_field_list
2400 }
2402 /* Add the fields for the discriminants into the record. */
2408 {
2409 /* If this is a record extension and this discriminant
2410 is the renaming of another discriminant, we've already
2411 handled the discriminant above. */
2416 gnu_field
2419 /* Make an expression using a PLACEHOLDER_EXPR from the
2420 FIELD_DECL node just created and link that with the
2421 corresponding GNAT defining identifier. Then add to the
2422 list of fields. */
2432 }
2434 /* Put the discriminants into the record (backwards), so we can
2435 know the appropriate discriminant to use for the names of the
2436 variants. */
2439 /* Add the listed fields into the record and finish up. */
2447 /* If this is an extension type, reset the tree for any
2448 inherited discriminants. Also remove the PLACEHOLDER_EXPR
2449 for non-inherited discriminants. */
2455 {
2459 else
2460 {
2465 }
2466 }
2468 /* If it is a tagged record force the type to BLKmode to insure
2469 that these objects will always be placed in memory. Do the
2470 same thing for limited record types. */
2474 /* If this is a derived type, we must make the alias set of this type
2475 the same as that of the type we are derived from. We assume here
2476 that the other type is already frozen. */
2482 /* Fill in locations of fields. */
2485 /* If there are any entities in the chain corresponding to
2486 components that we did not elaborate, ensure we elaborate their
2487 types if they are Itypes. */
2495 }
2499 /* If an equivalent type is present, that is what we should use.
2500 Otherwise, fall through to handle this like a record subtype
2501 since it may have constraints. */
2504 {
2509 }
2511 /* ... fall through ... */
2515 /* If Cloned_Subtype is Present it means this record subtype has
2516 identical layout to that type or subtype and we should use
2517 that GCC type for this one. The front end guarantees that
2518 the component list is shared. */
2520 {
2524 }
2526 /* Otherwise, first ensure the base type is elaborated. Then, if we are
2527 changing the type, make a new type with each field having the
2528 type of the field in the new subtype but having the position
2529 computed by transforming every discriminant reference according
2530 to the constraints. We don't see any difference between
2531 private and nonprivate type here since derivations from types should
2532 have been deferred until the completion of the private type. */
2533 else
2534 {
2536 tree gnu_base_type;
2537 tree gnu_orig_type;
2542 /* Get the base type initially for its alignment and sizes. But
2543 if it is a padded type, we do all the other work with the
2544 unpadded type. */
2553 {
2556 }
2558 /* When the type has discriminants, and these discriminants
2559 affect the shape of what it built, factor them in.
2561 If we are making a subtype of an Unchecked_Union (must be an
2562 Itype), just return the type.
2564 We can't just use Is_Constrained because private subtypes without
2565 discriminants of full types with discriminants with default
2566 expressions are Is_Constrained but aren't constrained! */
2574 {
2575 Entity_Id gnat_field;
2576 Entity_Id gnat_root_type;
2578 tree gnu_pos_list
2581 BIGGEST_ALIGNMENT);
2582 tree gnu_subst_list
2584 definition);
2585 tree gnu_temp;
2587 /* If this is a derived type, we may be seeing fields from any
2588 original records, so add those positions and discriminant
2589 substitutions to our lists. */
2593 {
2594 gnu_pos_list
2595 = compute_field_positions
2598 BIGGEST_ALIGNMENT);
2601 gnu_subst_list
2604 }
2610 gnat_entity);
2617 {
2618 tree gnu_old_field
2619 = gnat_to_gnu_entity
2621 tree gnu_offset
2623 gnu_pos_list));
2626 tree gnu_field_type
2630 unsigned int offset_align
2633 tree gnu_field;
2635 /* If there was a component clause, the field types must be
2636 the same for the type and subtype, so copy the data from
2637 the old field to avoid recomputation here. Also if the
2638 field is justified modular and the optimization in
2639 gnat_to_gnu_field was applied. */
2646 {
2649 }
2651 /* If this was a bitfield, get the size from the old field.
2652 Also ensure the type can be placed into a bitfield. */
2654 {
2660 }
2669 /* If the size is now a constant, we can set it as the
2670 size of the field when we make it. Otherwise, we need
2671 to deal with it specially. */
2675 gnu_field
2676 = create_field_decl
2682 {
2691 bitsize_unit_node));
2693 }
2697 SET_DECL_ORIGINAL_FIELD
2708 }
2713 /* Now set the size, alignment and alias set of the new type to
2714 match that of the old one, doing any substitutions, as
2715 above. */
2741 SET_TYPE_ADA_SIZE
2746 /* Recompute the mode of this record type now that we know its
2747 actual size. */
2750 /* Fill in locations of fields. */
2752 }
2754 /* If we've made a new type, record it and make an XVS type to show
2755 what this is a subtype of. Some debuggers require the XVS
2756 type to be output first, so do it in that order. */
2758 {
2760 {
2771 integer_type_node,
2772 gnu_subtype_marker,
2776 }
2783 }
2785 /* Otherwise, go down all the components in the new type and
2786 make them equivalent to those in the base type. */
2787 else
2794 get_gnu_tree
2796 }
2801 /* If we are not defining this entity, and we have incomplete
2802 entities being processed above us, make a dummy type and
2803 fill it in later. */
2805 {
2809 gnu_type
2810 = build_pointer_type
2823 }
2825 /* ... fall through ... */
2832 {
2834 Entity_Id gnat_desig_full
2836 Incomplete_Or_Private_Kind))
2838 /* We want to know if we'll be seeing the freeze node for any
2839 incomplete type we may be pointing to. */
2840 bool in_main_unit
2856 {
2858 {
2862 }
2864 Incomplete_Or_Private_Kind))
2866 }
2871 /* If either the designated type or its full view is an
2872 unconstrained array subtype, replace it with the type it's a
2873 subtype of. This avoids problems with multiple copies of
2874 unconstrained array types. */
2883 /* If the designated type is a subtype of an incomplete record type,
2884 use the parent type to avoid order of elaboration issues. This
2885 can lose some code efficiency, but there is no alternative. */
2891 /* If we are pointing to an incomplete type whose completion is an
2892 unconstrained array, make a fat pointer type instead of a pointer
2893 to VOID. The two types in our fields will be pointers to VOID and
2894 will be replaced in update_pointer_to. Similiarly, if the type
2895 itself is a dummy type or an unconstrained array. Also make
2896 a dummy TYPE_OBJECT_RECORD_TYPE in case we have any thin
2897 pointers to it. */
2913 && defer_incomplete_level
2917 {
2918 tree gnu_old
2922 tree fields;
2924 /* Show the dummy we get will be a fat pointer. */
2927 /* If the call above got something that has a pointer, that
2928 pointer is our type. This could have happened either
2929 because the type was elaborated or because somebody
2930 else executed the code below. */
2933 {
2939 fields
2941 create_field_decl
2946 ptr_void_type_node,
2949 /* Make sure we can place this into a register. */
2960 }
2961 }
2963 /* If we already know what the full type is, use it. */
2968 /* Get the type of the thing we are to point to and build a pointer
2969 to it. If it is a reference to an incomplete or private type with a
2970 full view that is a record, make a dummy type node and get the
2971 actual type later when we have verified it is safe. */
2977 {
2980 }
2982 /* Likewise if we are pointing to a record or array and we are to defer
2983 elaborating incomplete types. We do this since this access type
2984 may be the full view of some private type. Note that the
2985 unconstrained array case is handled above. */
2993 {
2996 }
2998 {
2999 gnu_type
3001 p_mode,
3004 }
3005 else
3008 /* It is possible that the above call to gnat_to_gnu_type resolved our
3009 type. If so, just return it. */
3011 {
3014 }
3016 /* If we have a GCC type for the designated type, possibly modify it
3017 if we are pointing only to constant objects and then make a pointer
3018 to it. Don't do this for unconstrained arrays. */
3020 {
3023 {
3024 gnu_desig_type
3025 = build_qualified_type
3029 /* Some extra processing is required if we are building a
3030 pointer to an incomplete type (in the GCC sense). We might
3031 have such a type if we just made a dummy, or directly out
3032 of the call to gnat_to_gnu_type above if we are processing
3033 an access type for a record component designating the
3034 record type itself. */
3036 {
3037 /* We must ensure that the pointer to variant we make will
3038 be processed by update_pointer_to when the initial type
3039 is completed. Pretend we made a dummy and let further
3040 processing act as usual. */
3043 /* We must ensure that update_pointer_to will not retrieve
3044 the dummy variant when building a properly qualified
3045 version of the complete type. We take advantage of the
3046 fact that get_qualified_type is requiring TYPE_NAMEs to
3047 match to influence build_qualified_type and then also
3048 update_pointer_to here. */
3051 }
3052 }
3054 gnu_type
3057 }
3059 /* If we are not defining this object and we made a dummy pointer,
3060 save our current definition, evaluate the actual type, and replace
3061 the tentative type we made with the actual one. If we are to defer
3062 actually looking up the actual type, make an entry in the
3063 deferred list. */
3066 {
3067 tree gnu_old_type
3073 gnu_type
3074 = build_pointer_type
3075 (TYPE_OBJECT_RECORD_TYPE
3085 /* Note that the call to gnat_to_gnu_type here might have
3086 updated gnu_old_type directly, in which case it is not a
3087 dummy type any more when we get into update_pointer_to.
3089 This may happen for instance when the designated type is a
3090 record type, because their elaboration starts with an
3091 initial node from make_dummy_type, which may yield the same
3092 node as the one we got.
3094 Besides, variants of this non-dummy type might have been
3095 created along the way. update_pointer_to is expected to
3096 properly take care of those situations. */
3099 else
3100 {
3108 }
3109 }
3110 }
3117 else
3118 /* The runtime representation is the equivalent type. */
3132 /* We treat this as identical to its base type; any constraint is
3133 meaningful only to the front end.
3135 The designated type must be elaborated as well, if it does
3136 not have its own freeze node. Designated (sub)types created
3137 for constrained components of records with discriminants are
3138 not frozen by the front end and thus not elaborated by gigi,
3139 because their use may appear before the base type is frozen,
3140 and because it is not clear that they are needed anywhere in
3141 Gigi. With the current model, there is no correct place where
3142 they could be elaborated. */
3149 {
3150 /* If we are not defining this entity, and we have incomplete
3151 entities being processed above us, make a dummy type and
3152 elaborate it later. */
3154 {
3157 tree gnu_ptr_type
3158 = build_pointer_type
3165 }
3166 else if
3168 Incomplete_Or_Private_Kind))
3169 { ;}
3170 else
3173 }
3178 /* Subprogram Entities
3180 The following access functions are defined for subprograms (functions
3181 or procedures):
3183 First_Formal The first formal parameter.
3184 Is_Imported Indicates that the subprogram has appeared in
3185 an INTERFACE or IMPORT pragma. For now we
3186 assume that the external language is C.
3187 Is_Inlined True if the subprogram is to be inlined.
3189 In addition for function subprograms we have:
3191 Etype Return type of the function.
3193 Each parameter is first checked by calling must_pass_by_ref on its
3194 type to determine if it is passed by reference. For parameters which
3195 are copied in, if they are Ada IN OUT or OUT parameters, their return
3196 value becomes part of a record which becomes the return type of the
3197 function (C function - note that this applies only to Ada procedures
3198 so there is no Ada return type). Additional code to store back the
3199 parameters will be generated on the caller side. This transformation
3200 is done here, not in the front-end.
3202 The intended result of the transformation can be seen from the
3203 equivalent source rewritings that follow:
3205 struct temp {int a,b};
3206 procedure P (A,B: IN OUT ...) is temp P (int A,B) {
3207 .. ..
3208 end P; return {A,B};
3209 }
3210 procedure call
3212 {
3213 temp t;
3214 P(X,Y); t = P(X,Y);
3215 X = t.a , Y = t.b;
3216 }
3218 For subprogram types we need to perform mainly the same conversions to
3219 GCC form that are needed for procedures and function declarations. The
3220 only difference is that at the end, we make a type declaration instead
3221 of a function declaration. */
3226 {
3227 /* The first GCC parameter declaration (a PARM_DECL node). The
3228 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3229 actually is the head of this parameter list. */
3231 /* The type returned by a function. If the subprogram is a procedure
3232 this type should be void_type_node. */
3234 /* List of fields in return type of procedure with copy in copy out
3235 parameters. */
3237 /* Non-null for subprograms containing parameters passed by copy in
3238 copy out (Ada IN OUT or OUT parameters not passed by reference),
3239 in which case it is the list of nodes used to specify the values of
3240 the in out/out parameters that are returned as a record upon
3241 procedure return. The TREE_PURPOSE of an element of this list is
3242 a field of the record and the TREE_VALUE is the PARM_DECL
3243 corresponding to that field. This list will be saved in the
3244 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3246 /* If an import pragma asks to map this subprogram to a GCC builtin,
3247 this is the builtin DECL node. */
3249 Entity_Id gnat_param;
3252 bool extern_flag
3264 /* A parameter may refer to this type, so defer completion
3265 of any incomplete types. */
3268 /* If the subprogram has an alias, it is probably inherited, so
3269 we can use the original one. If the original "subprogram"
3270 is actually an enumeration literal, it may be the first use
3271 of its type, so we must elaborate that type now. */
3273 {
3280 /* Elaborate any Itypes in the parameters of this entity. */
3288 }
3290 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3291 corresponding DECL node.
3293 We still want the parameter associations to take place because the
3294 proper generation of calls depends on it (a GNAT parameter without
3295 a corresponding GCC tree has a very specific meaning), so we don't
3296 just break here. */
3300 /* ??? What if we don't find the builtin node above ? warn ? err ?
3301 In the current state we neither warn nor err, and calls will just
3302 be handled as for regular subprograms. */
3307 /* If this function returns by reference, make the actual
3308 return type of this function the pointer and mark the decl. */
3310 {
3313 }
3315 /* If the Mechanism is By_Reference, ensure the return type uses
3316 the machine's by-reference mechanism, which may not the same
3317 as above (e.g., it might be by passing a fake parameter). */
3320 {
3323 }
3325 /* If we are supposed to return an unconstrained array,
3326 actually return a fat pointer and make a note of that. Return
3327 a pointer to an unconstrained record of variable size. */
3329 {
3332 }
3334 /* If the type requires a transient scope, the result is allocated
3335 on the secondary stack, so the result type of the function is
3336 just a pointer. */
3338 {
3341 }
3343 /* If the type is a padded type and the underlying type would not
3344 be passed by reference or this function has a foreign convention,
3345 return the underlying type. */
3353 /* If the return type is unconstrained, that means it must have a
3354 maximum size. We convert the function into a procedure and its
3355 caller will pass a pointer to an object of that maximum size as the
3356 first parameter when we call the function. */
3358 {
3360 gnu_param_list
3365 }
3367 /* If the return type has a size that overflows, we cannot have
3368 a function that returns that type. This usage doesn't make
3369 sense anyway, so give an error here. */
3372 {
3374 gnat_entity);
3380 }
3382 /* Look at all our parameters and get the type of
3383 each. While doing this, build a copy-out structure if
3384 we need one. */
3389 {
3399 /* Builtins are expanded inline and there is no real call sequence
3400 involved. so the type expected by the underlying expander is
3401 always the type of each argument "as is". */
3405 /* Otherwise, see if a Mechanism was supplied that forced this
3406 parameter to be passed one way or another. */
3410 ;
3418 {
3424 else
3426 }
3427 else
3430 /* If this is either a foreign function or if the
3431 underlying type won't be passed by refererence, strip off
3432 possible padding type. */
3440 /* If this is an IN parameter it is read-only, so make a variant
3441 of the type that is read-only.
3443 ??? However, if this is an unconstrained array, that type can
3444 be very complex. So skip it for now. Likewise for any other
3445 self-referential type. */
3449 gnu_param_type
3454 /* For foreign conventions, pass arrays as a pointer to the
3455 underlying type. First check for unconstrained array and get
3456 the underlying array. Then get the component type and build
3457 a pointer to it. */
3460 gnu_param_type
3465 gnu_param_type
3466 = build_pointer_type
3471 && !req_by_copy
3473 {
3474 /* Strip off any multi-dimensional entries, then strip
3475 off the last array to get the component type. */
3484 gnu_param_type
3490 }
3492 /* Fat pointers are passed as thin pointers for foreign
3493 conventions. */
3496 gnu_param_type
3500 /* If we must pass or were requested to pass by reference, do so.
3501 If we were requested to pass by copy, do so.
3502 Otherwise, for foreign conventions, pass all in out parameters
3503 or aggregates by reference. For COBOL and Fortran, pass
3504 all integer and FP types that way too. For Convention Ada,
3505 use the standard Ada default. */
3507 || (!req_by_copy
3517 /* For convention Ada, see if we pass by reference
3518 by default. */
3521 {
3524 }
3532 /* If this is an OUT parameter that isn't passed by reference
3533 and isn't a pointer or aggregate, we don't make a PARM_DECL
3534 for it. Instead, it will be a VAR_DECL created when we process
3535 the procedure. For the special parameter of Valued_Procedure,
3536 never pass it in.
3538 An exception is made to cover the RM-6.4.1 rule requiring "by
3539 copy" out parameters with discriminants or implicit initial
3540 values to be handled like in out parameters. These type are
3541 normally built as aggregates, and hence passed by reference,
3542 except for some packed arrays which end up encoded in special
3543 integer types.
3545 The exception we need to make is then for packed arrays of
3546 records with discriminants or implicit initial values. We have
3547 no light/easy way to check for the latter case, so we merely
3548 check for packed arrays of records. This may lead to useless
3549 copy-in operations, but in very rare cases only, as these would
3550 be exceptions in a set of already exceptional situations. */
3553 || (!by_descr_p
3561 else
3562 {
3563 gnu_param
3564 = create_param_decl
3566 by_ref_p || by_component_ptr_p
3580 /* If a parameter is a pointer, this function may modify
3581 memory through it and thus shouldn't be considered
3582 a pure function. Also, the memory may be modified
3583 between two calls, so they can't be CSE'ed. The latter
3584 case also handles by-ref parameters. */
3588 }
3591 {
3593 {
3598 }
3607 gnu_return_list);
3608 }
3609 }
3611 /* Do not compute record for out parameters if subprogram is
3612 stubbed since structures are incomplete for the back-end. */
3618 /* If we have a CICO list but it has only one entry, we convert
3619 this function into a function that simply returns that one
3620 object. */
3624 #ifdef _WIN32
3626 {
3636 }
3637 #endif
3639 /* Both lists ware built in reverse. */
3643 gnu_type
3646 returns_by_ref,
3648 returns_by_target_ptr);
3650 /* A subprogram (something that doesn't return anything) shouldn't
3651 be considered Pure since there would be no reason for such a
3652 subprogram. Note that procedures with Out (or In Out) parameters
3653 have already been converted into a function with a return type. */
3657 gnu_type
3665 /* If we have a builtin decl for that function, check the signatures
3666 compatibilities. If the signatures are compatible, use the builtin
3667 decl. If they are not, we expect the checker predicate to have
3668 posted the appropriate errors, and just continue with what we have
3669 so far. */
3671 {
3675 {
3679 }
3680 }
3682 /* If there was no specified Interface_Name and the external and
3683 internal names of the subprogram are the same, only use the
3684 internal name to allow disambiguation of nested subprograms. */
3688 /* If we are defining the subprogram and it has an Address clause
3689 we must get the address expression from the saved GCC tree for the
3690 subprogram if it has a Freeze_Node. Otherwise, we elaborate
3691 the address expression here since the front-end has guaranteed
3692 in that case that the elaboration has no effects. If there is
3693 an Address clause and we are not defining the object, just
3694 make it a constant. */
3696 {
3700 gnu_address
3711 gnu_decl
3716 }
3722 else
3723 {
3728 gnat_entity);
3731 }
3732 }
3743 /* If this type does not have a full view in the unit we are
3744 compiling, then just get the type from its Etype. */
3746 {
3747 /* If this is an incomplete type with no full view, it must
3748 be a Taft Amendement type, so just return a dummy type. */
3755 else
3756 {
3760 }
3763 }
3765 /* Otherwise, if we are not defining the type now, get the
3766 type from the full view. But always get the type from the full
3767 view for define on use types, since otherwise we won't see them! */
3774 {
3779 }
3781 /* For incomplete types, make a dummy type entry which will be
3782 replaced later. */
3785 /* Save this type as the full declaration's type so we can do any needed
3786 updates when we see it. */
3793 /* Simple class_wide types are always viewed as their root_type
3794 by Gigi unless an Equivalent_Type is specified. */
3798 else
3810 else
3822 /* Nothing at all to do here, so just return an ERROR_MARK and claim
3823 we've already saved it, so we don't try to. */
3830 }
3832 /* If we had a case where we evaluated another type and it might have
3833 defined this one, handle it here. */
3835 {
3838 }
3840 /* If we are processing a type and there is either no decl for it or
3841 we just made one, do some common processing for the type, such as
3842 handling alignment and possible padding. */
3845 {
3853 /* ??? Don't set the size for a String_Literal since it is either
3854 confirming or we don't handle it properly (if the low bound is
3855 non-constant). */
3861 /* If a size was specified, see if we can make a new type of that size
3862 by rearranging the type, for example from a fat to a thin pointer. */
3864 {
3865 gnu_type
3872 }
3874 /* If the alignment hasn't already been processed and this is
3875 not an unconstrained array, see if an alignment is specified.
3876 If not, we pick a default alignment for atomic objects. */
3878 ;
3892 /* See if we need to pad the type. If we did, and made a record,
3893 the name of the new type may be changed. So get it back for
3894 us when we make the new TYPE_DECL below. */
3899 {
3903 }
3907 /* If we are at global level, GCC will have applied variable_size to
3908 the type, but that won't have done anything. So, if it's not
3909 a constant or self-referential, call elaborate_expression_1 to
3910 make a variable for the size rather than calculating it each time.
3911 Handle both the RM size and the actual size. */
3916 {
3920 {
3927 }
3928 else
3929 {
3936 /* ??? For now, store the size as a multiple of the alignment
3937 in bytes so that we can see the alignment from the tree. */
3939 = build_binary_op
3941 elaborate_expression_1
3952 SET_TYPE_ADA_SIZE
3955 gnat_entity,
3959 }
3960 }
3962 /* If this is a record type or subtype, call elaborate_expression_1 on
3963 any field position. Do this for both global and local types.
3964 Skip any fields that we haven't made trees for to avoid problems with
3965 class wide types. */
3970 {
3973 /* ??? Unfortunately, GCC needs to be able to prove the
3974 alignment of this offset and if it's a variable, it can't.
3975 In GCC 3.4, we'll use DECL_OFFSET_ALIGN in some way, but
3976 right now, we have to put in an explicit multiply and
3977 divide by that value. */
3980 = build_binary_op
3982 elaborate_expression_1
3991 }
3995 | (TYPE_QUAL_VOLATILE
4008 else
4010 }
4013 {
4016 /* Back-annotate the Alignment of the type if not already in the
4017 tree. Likewise for sizes. */
4023 {
4024 /* If the size is self-referential, we annotate the maximum
4025 value of that size. */
4034 {
4035 /* In this mode the tag and the parent components are not
4036 generated by the front-end, so the sizes must be adjusted
4037 explicitly now. */
4043 {
4044 size_offset
4048 }
4049 else
4057 }
4058 }
4062 }
4071 /* If we haven't already, associate the ..._DECL node that we just made with
4072 the input GNAT entity node. */
4076 /* If this is an enumeral or floating-point type, we were not able to set
4077 the bounds since they refer to the type. These bounds are always static.
4079 For enumeration types, also write debugging information and declare the
4080 enumeration literal table, if needed. */
4084 {
4087 /* If this is a padded type, we need to use the underlying type. */
4092 /* If this is a floating point type and we haven't set a floating
4093 point type yet, use this in the evaluation of the bounds. */
4103 {
4106 /* Since this has both a typedef and a tag, avoid outputting
4107 the name twice. */
4110 }
4111 }
4113 /* If we deferred processing of incomplete types, re-enable it. If there
4114 were no other disables and we have some to process, do so. */
4116 {
4122 {
4129 }
4130 }
4132 /* If we are not defining this type, see if it's in the incomplete list.
4133 If so, handle that list entry now. */
4135 {
4140 {
4144 }
4145 }
4148 force_global--;
4157 }
4158 \f
4159 /* Given GNAT_ENTITY, elaborate all expressions that are required to
4160 be elaborated at the point of its definition, but do nothing else. */
4162 void
4164 {
4166 {
4173 {
4177 /* ??? Tests for avoiding static constaint error expression
4178 is needed until the front stops generating bogus conversions
4179 on bounds of real types. */
4188 }
4191 {
4195 /* If this is a record extension, go a level further to find the
4196 record definition. */
4199 }
4209 {
4210 Node_Id gnat_discriminant_expr;
4211 Entity_Id gnat_field;
4214 gnat_discriminant_expr
4219 /* ??? For now, ignore access discriminants. */
4222 gnat_entity,
4224 }
4227 }
4228 }
4229 \f
4230 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
4231 any entities on its entity chain similarly. */
4233 void
4235 {
4236 Entity_Id gnat_sub_entity;
4239 /* If this has an entity list, process all in the list. */
4256 /* Now clear this if it has been defined, but only do so if it isn't
4257 a subprogram or parameter. We could refine this, but it isn't
4258 worth it. If this is statically allocated, it is supposed to
4259 hang around out of cope. */
4262 {
4265 }
4266 }
4267 \f
4268 /* Set the alias set of GNU_NEW_TYPE to be that of GNU_OLD_TYPE. If this
4269 is a multi-dimensional array type, do this recursively. */
4271 static void
4273 {
4277 {
4278 /* We need to be careful here in case GNU_OLD_TYPE is an unconstrained
4279 array. In that case, it doesn't have the same shape as GNU_NEW_TYPE,
4280 so we need to go down to what does. */
4282 gnu_old_type
4286 }
4290 }
4291 \f
4292 /* Return a TREE_LIST describing the substitutions needed to reflect
4293 discriminant substitutions from GNAT_SUBTYPE to GNAT_TYPE and add
4294 them to GNU_LIST. If GNAT_TYPE is not specified, use the base type
4295 of GNAT_SUBTYPE. The substitions can be in any order. TREE_PURPOSE
4296 gives the tree for the discriminant and TREE_VALUES is the replacement
4297 value. They are in the form of operands to substitute_in_expr.
4298 DEFINITION is as in gnat_to_gnu_entity. */
4300 static tree
4303 {
4304 Entity_Id gnat_discrim;
4305 Node_Id gnat_value;
4316 /* Ignore access discriminants. */
4319 elaborate_expression
4323 gnu_list);
4326 }
4327 \f
4328 /* For the following two functions: for each GNAT entity, the GCC
4329 tree node used as a dummy for that entity, if any. */
4333 /* Initialize the above table. */
4335 void
4337 {
4338 Node_Id gnat_node;
4346 }
4348 /* Make a dummy type corresponding to GNAT_TYPE. */
4350 tree
4352 {
4353 Entity_Id gnat_underlying;
4354 tree gnu_type;
4356 /* Find a full type for GNAT_TYPE, taking into account any class wide
4357 types. */
4367 ;
4369 /* If it there already a dummy type, use that one. Else make one. */
4373 /* If this is a record, make this a RECORD_TYPE or UNION_TYPE; else make
4374 it a VOID_TYPE. */
4378 else
4389 }
4390 \f
4391 /* Return true if the size represented by GNU_SIZE can be handled by an
4392 allocation. If STATIC_P is true, consider only what can be done with a
4393 static allocation. */
4395 static bool
4397 {
4398 HOST_WIDE_INT our_size;
4400 /* If this is not a static allocation, the only case we want to forbid
4401 is an overflowing size. That will be converted into a raise a
4402 Storage_Error. */
4407 /* Otherwise, we need to deal with both variable sizes and constant
4408 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
4409 since assemblers may not like very large sizes. */
4415 }
4416 \f
4417 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
4419 static void
4421 {
4422 Node_Id gnat_temp;
4427 {
4437 {
4439 (gnat_to_gnu
4446 (gnat_to_gnu
4447 (Expression
4450 }
4453 {
4472 }
4479 /* If we have an argument specified together with an attribute name,
4480 make it a single TREE_VALUE entry in a list of arguments, as GCC
4481 expects it. */
4484 else
4487 attr->error_point
4491 }
4492 }
4493 \f
4494 /* Get the unpadded version of a GNAT type. */
4496 tree
4498 {
4505 }
4506 \f
4507 /* Called when we need to protect a variable object using a save_expr. */
4509 tree
4511 {
4518 {
4526 }
4527 else
4529 }
4530 \f
4531 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
4532 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
4533 return the GCC tree to use for that expression. GNU_NAME is the
4534 qualification to use if an external name is appropriate and DEFINITION is
4535 nonzero if this is a definition of GNAT_ENTITY. If NEED_VALUE is nonzero,
4536 we need a result. Otherwise, we are just elaborating this for
4537 side-effects. If NEED_DEBUG is nonzero we need the symbol for debugging
4538 purposes even if it isn't needed for code generation. */
4540 static tree
4544 {
4545 tree gnu_expr;
4547 /* If we already elaborated this expression (e.g., it was involved
4548 in the definition of a private type), use the old value. */
4552 /* If we don't need a value and this is static or a discriment, we
4553 don't need to do anything. */
4560 /* Otherwise, convert this tree to its GCC equivalant. */
4561 gnu_expr
4565 /* Save the expression in case we try to elaborate this entity again. Since
4566 this is not a DECL, don't check it. Don't save if it's a discriminant. */
4571 }
4573 /* Similar, but take a GNU expression. */
4575 static tree
4579 {
4581 /* Strip any conversions to see if the expression is a readonly variable.
4582 ??? This really should remain readonly, but we have to think about
4583 the typing of the tree here. */
4588 /* In most cases, we won't see a naked FIELD_DECL here because a
4589 discriminant reference will have been replaced with a COMPONENT_REF
4590 when the type is being elaborated. However, there are some cases
4591 involving child types where we will. So convert it to a COMPONENT_REF
4592 here. We have to hope it will be at the highest level of the
4593 expression in these cases. */
4599 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
4600 that is a constant, make a variable that is initialized to contain the
4601 bound when the package containing the definition is elaborated. If
4602 this entity is defined at top level and a bound or discriminant value
4603 isn't a constant or a reference to a discriminant, replace the bound
4604 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
4605 rely here on the fact that an expression cannot contain both the
4606 discriminant and some other variable. */
4613 /* If this is a static expression or contains a discriminant, we don't
4614 need the variable for debugging (and can't elaborate anyway if a
4615 discriminant). */
4621 /* Now create the variable if we need it. */
4623 gnu_decl
4628 gnat_entity);
4630 /* We only need to use this variable if we are in global context since GCC
4631 can do the right thing in the local case. */
4636 else
4638 }
4639 \f
4640 /* Create a record type that contains a field of TYPE with a starting bit
4641 position so that it is aligned to ALIGN bits and is SIZE bytes long. */
4643 tree
4645 {
4650 place));
4659 /* The bit position is obtained by "and"ing the alignment minus 1
4660 with the two's complement of the address and multiplying
4661 by the number of bits per unit. Do all this in sizetype. */
4666 size_addr_place),
4669 bitsize_unit_node);
4671 /* Create the field, with -1 as the 'addressable' indication to avoid the
4672 creation of a bitfield. We don't need one, it would have damaging
4673 consequences on the alignment computation, and create_field_decl would
4674 make one without this special argument, for instance because of the
4675 complex position expression. */
4684 bitsize_unit_node),
4690 }
4691 \f
4692 /* TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE, with BLKmode that's
4693 being used as the field type of a packed record. See if we can rewrite it
4694 as a record that has a non-BLKmode type, which we can pack tighter. If so,
4695 return the new type. If not, return the original type. */
4697 static tree
4699 {
4702 tree old_field;
4704 /* Copy the name and flags from the old type to that of the new and set
4705 the alignment to try for an integral type. For QUAL_UNION_TYPE,
4706 also copy the size. */
4715 {
4718 }
4724 /* Now copy the fields, keeping the position and size. */
4727 {
4729 tree new_field;
4745 SET_DECL_ORIGINAL_FIELD
4754 }
4759 }
4760 \f
4761 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
4762 if needed. We have already verified that SIZE and TYPE are large enough.
4764 GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
4765 to issue a warning.
4767 IS_USER_TYPE is true if we must be sure we complete the original type.
4769 DEFINITION is true if this type is being defined.
4771 SAME_RM_SIZE is true if the RM_Size of the resulting type is to be
4772 set to its TYPE_SIZE; otherwise, it's set to the RM_Size of the original
4773 type. */
4775 tree
4779 {
4781 tree record;
4782 tree field;
4784 /* If TYPE is a padded type, see if it agrees with any size and alignment
4785 we were given. If so, return the original type. Otherwise, strip
4786 off the padding, since we will either be returning the inner type
4787 or repadding it. If no size or alignment is specified, use that of
4788 the original padded type. */
4791 {
4808 }
4810 /* If the size is either not being changed or is being made smaller (which
4811 is not done here (and is only valid for bitfields anyway), show the size
4812 isn't changing. Likewise, clear the alignment if it isn't being
4813 changed. Then return if we aren't doing anything. */
4827 /* We used to modify the record in place in some cases, but that could
4828 generate incorrect debugging information. So make a new record
4829 type and name. */
4835 /* If we were making a type, complete the original type and give it a
4836 name. */
4843 gnat_entity);
4845 /* If we are changing the alignment and the input type is a record with
4846 BLKmode and a small constant size, try to make a form that has an
4847 integral mode. That might allow this record to have an integral mode,
4848 which will be much more efficient. There is no point in doing this if a
4849 size is specified unless it is also smaller than the biggest alignment
4850 and it is incorrect to do this if the size of the original type is not a
4851 multiple of the alignment. */
4857 && (!size
4879 /* Keep the RM_Size of the padded record as that of the old record
4880 if requested. */
4883 /* Unless debugging information isn't being written for the input type,
4884 write a record that shows what we are a subtype of and also make a
4885 variable that indicates our size, if variable. */
4889 {
4910 }
4917 /* If the size was widened explicitly, maybe give a warning. */
4923 {
4936 /* Generate message only for entities that come from source, since
4937 if we have an entity created by expansion, the message will be
4938 generated for some other corresponding source entity. */
4941 gnat_entity,
4948 }
4951 }
4952 \f
4953 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
4954 the value passed against the list of choices. */
4956 tree
4958 {
4959 Node_Id choice;
4960 Node_Id gnat_temp;
4965 {
4967 {
4972 /* There's no good type to use here, so we might as well use
4973 integer_type_node. */
4974 this_test
4988 this_test
4998 /* This represents either a subtype range, an enumeration
4999 literal, or a constant Ekind says which. If an enumeration
5000 literal or constant, fall through to the next case. */
5003 {
5009 this_test
5016 }
5017 /* ... fall through ... */
5022 single);
5031 }
5035 }
5038 }
5039 \f
5040 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
5041 placed in GNU_RECORD_TYPE.
5043 PACKED is 1 if the enclosing record is packed and -1 if the enclosing
5044 record has a Component_Alignment of Storage_Unit.
5046 DEFINITION is true if this field is for a record being defined. */
5048 static tree
5051 {
5057 tree gnu_field;
5058 bool needs_strict_alignment
5062 /* If this field requires strict alignment or contains an item of
5063 variable sized, pretend it isn't packed. */
5067 /* For packed records, this is one of the few occasions on which we use
5068 the official RM size for discrete or fixed-point components, instead
5069 of the normal GNAT size stored in Esize. See description in Einfo:
5070 "Handling of Type'Size Values" for further details. */
5080 /* If the field's type is justified modular and the size of the packed
5081 array it wraps is the same as that of the field, we can make the field
5082 the type of the inner object. Note that we may need to do so if the
5083 record is packed or the field has a component clause, but these cases
5084 are handled later. */
5091 /* If we are packing this record, have a specified size that's smaller than
5092 that of the field type, or a position is specified, and the field type
5093 is also a record that's BLKmode and with a small constant size, see if
5094 we can get a better form of the type that allows more packing. If we
5095 can, show a size was specified for it if there wasn't one so we know to
5096 make this a bitfield and avoid making things wider. */
5101 && (packed
5105 {
5110 }
5112 /* If we are packing the record and the field is BLKmode, round the
5113 size up to a byte boundary. */
5118 {
5123 /* Ensure the position does not overlap with the parent subtype,
5124 if there is one. */
5126 {
5127 tree gnu_parent
5133 {
5134 post_error_ne_tree
5138 }
5139 }
5141 /* If this field needs strict alignment, ensure the record is
5142 sufficiently aligned and that that position and size are
5143 consistent with the alignment. */
5145 {
5152 /* If Atomic, the size must match exactly and if aliased, the size
5153 must not be less than the rounded size. */
5156 {
5157 post_error_ne_tree
5163 }
5167 {
5168 post_error_ne_tree
5171 gnu_min_size);
5173 }
5178 {
5180 post_error_ne_num
5186 post_error_ne_num
5192 post_error_ne_num
5196 else
5200 }
5201 }
5205 }
5207 /* If the record has rep clauses and this is the tag field, make a rep
5208 clause for it as well. */
5211 {
5214 }
5216 /* We need to make the size the maximum for the type if it is
5217 self-referential and an unconstrained type. In that case, we can't
5218 pack the field since we can't make a copy to align it. */
5220 && !gnu_size
5223 {
5226 }
5228 /* If no size is specified (or if there was an error), don't specify a
5229 position. */
5232 else
5233 {
5234 /* If the field's type is justified modular, we would need to remove
5235 the wrapper to (better) meet the layout requirements. However we
5236 can do so only if the field is not aliased to preserve the unique
5237 layout and if the prescribed size is not greater than that of the
5238 packed array to preserve the justification. */
5246 gnu_field_type
5251 }
5256 /* Now create the decl for the field. */
5268 }
5269 \f
5270 /* Return true if TYPE is a type with variable size, a padding type with a
5271 field of variable size or is a record that has a field such a field. */
5273 static bool
5275 {
5276 tree field;
5278 /* We need not be concerned about this at all if we don't have
5279 strict alignment. */
5297 }
5298 \f
5299 /* Return a GCC tree for a record type given a GNAT Component_List and a chain
5300 of GCC trees for fields that are in the record and have already been
5301 processed. When called from gnat_to_gnu_entity during the processing of a
5302 record type definition, the GCC nodes for the discriminants will be on
5303 the chain. The other calls to this function are recursive calls from
5304 itself for the Component_List of a variant and the chain is empty.
5306 PACKED is 1 if this is for a record with "pragma pack" and -1 is this is
5307 for a record type with "pragma component_alignment (storage_unit)".
5309 DEFINITION is true if we are defining this record.
5311 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
5312 with a rep clause is to be added. If it is nonzero, that is all that
5313 should be done with such fields.
5315 CANCEL_ALIGNMENT, if true, means the alignment should be zeroed before
5316 laying out the record. This means the alignment only serves to force fields
5317 to be bitfields, but not require the record to be that aligned. This is
5318 used for variants.
5320 ALL_REP, if true, means a rep clause was found for all the fields. This
5321 simplifies the logic since we know we're not in the mixed case.
5323 The processing of the component list fills in the chain with all of the
5324 fields of the record and then the record type is finished. */
5326 static void
5331 {
5332 Node_Id component_decl;
5333 Entity_Id gnat_field;
5334 Node_Id variant_part;
5335 Node_Id variant;
5341 /* For each variable within each component declaration create a GCC field
5342 and add it to the list, skipping any pragmas in the list. */
5348 {
5353 else
5354 {
5358 /* If this is the _Tag field, put it before any discriminants,
5359 instead of after them as is the case for all other fields.
5360 Ignore field of void type if only annotating. */
5363 else
5364 {
5367 }
5368 }
5371 }
5373 /* At the end of the component list there may be a variant part. */
5376 /* If this is an unchecked union, each variant must have exactly one
5377 component, each of which becomes one component of this union. */
5382 {
5383 component_decl
5387 definition);
5391 }
5393 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
5394 mutually exclusive and should go in the same memory. To do this we need
5395 to treat each variant as a record whose elements are created from the
5396 component list for the variant. So here we create the records from the
5397 lists for the variants and put them all into the QUAL_UNION_TYPE. */
5399 {
5401 Node_Id variant;
5403 tree gnu_union_field;
5406 tree gnu_var_name
5407 = concat_id_with_name
5421 {
5423 tree gnu_inner_name;
5424 tree gnu_qual;
5432 /* Set the alignment of the inner type in case we need to make
5433 inner objects into bitfields, but then clear it out
5434 so the record actually gets only the alignment required. */
5438 /* Similarly, if the outer record has a size specified and all fields
5439 have record rep clauses, we can propagate the size into the
5440 variant part. */
5442 {
5446 }
5458 (all_rep_and_size
5460 (all_rep_and_size
5468 }
5470 /* We use to delete the empty variants from the end. However,
5471 we no longer do that because we need them to generate complete
5472 debugging information for the variant record. Otherwise,
5473 the union type definition will be missing the fields associated
5474 to these empty variants. */
5476 /* Only make the QUAL_UNION_TYPE if there are any non-empty variants. */
5478 {
5480 {
5484 }
5489 gnu_union_field
5491 packed,
5498 }
5499 }
5501 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
5502 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do this
5503 in a separate pass since we want to handle the discriminants but can't
5504 play with them until we've used them in debugging data above.
5506 ??? Note: if we then reorder them, debugging information will be wrong,
5507 but there's nothing that can be done about this at the moment. */
5510 {
5512 {
5517 else
5523 }
5524 else
5525 {
5528 }
5529 }
5531 /* If we have any items in our rep'ed field list, it is not the case that all
5532 the fields in the record have rep clauses, and P_REP_LIST is nonzero,
5533 set it and ignore the items. Otherwise, sort the fields by bit position
5534 and put them into their own record if we have any fields without
5535 rep clauses. */
5539 {
5540 tree gnu_rep_type
5546 /* Set DECL_SECTION_NAME to increasing integers so we have a
5547 stable sort. */
5550 {
5553 }
5557 /* Put the fields in the list in order of increasing position, which
5558 means we start from the end. */
5561 {
5566 }
5569 {
5575 }
5576 else
5577 {
5580 }
5581 }
5588 }
5589 \f
5590 /* Called via qsort from the above. Returns -1, 1, depending on the
5591 bit positions and ordinals of the two fields. */
5593 static int
5595 {
5600 return
5605 else
5607 }
5608 \f
5609 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
5610 placed into an Esize, Component_Bit_Offset, or Component_Size value
5611 in the GNAT tree. */
5613 static Uint
5615 {
5617 TCode tcode;
5622 /* If back annotation is suppressed by the front end, return No_Uint */
5626 /* See if we've already saved the value for this node. */
5630 /* If we do not return inside this switch, TCODE will be set to the
5631 code to use for a Create_Node operand and LEN (set above) will be
5632 the number of recursive calls for us to make. */
5635 {
5640 /* This may have come from a conversion from some smaller type,
5641 so ensure this is in bitsizetype. */
5644 /* For negative values, use NEGATE_EXPR of the supplied value. */
5646 {
5647 /* The rediculous code below is to handle the case of the largest
5648 negative integer. */
5651 tree temp;
5654 {
5655 negative_size
5658 bitsize_one_node));
5660 }
5667 }
5674 /* This peculiar test is to make sure that the size fits in an int
5675 on machines where HOST_WIDE_INT is not "int". */
5678 else
5682 /* The only case we handle here is a simple discriminant reference. */
5690 else
5696 /* Now just list the operations we handle. */
5727 }
5729 /* Now get each of the operands that's relevant for this code. If any
5730 cannot be expressed as a repinfo node, say we can't. */
5735 {
5739 }
5744 }
5746 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding
5747 GCC type, set Component_Bit_Offset and Esize to the position and size
5748 used by Gigi. */
5750 static void
5752 {
5753 tree gnu_list;
5754 tree gnu_entry;
5755 Entity_Id gnat_field;
5757 /* We operate by first making a list of all field and their positions
5758 (we can get the sizes easily at any time) by a recursive call
5759 and then update all the sizes into the tree. */
5762 BIGGEST_ALIGNMENT);
5769 {
5772 gnu_entry
5774 gnu_list);
5777 {
5779 {
5780 /* In this mode the tag and parent components have not been
5781 generated, so we add the appropriate offset to each
5782 component. For a component appearing in the current
5783 extension, the offset is the size of the parent. */
5786 parent_offset
5788 bitsizetype);
5789 else
5791 }
5793 Set_Component_Bit_Offset
5795 annotate_value
5800 parent_offset)));
5804 }
5808 {
5809 /* If there is no gnu_entry, this is an inherited component whose
5810 position is the same as in the parent type. */
5811 Set_Component_Bit_Offset
5816 }
5817 }
5818 }
5820 /* Scan all fields in GNU_TYPE and build entries where TREE_PURPOSE is the
5821 FIELD_DECL and TREE_VALUE a TREE_LIST with TREE_PURPOSE being the byte
5822 position and TREE_VALUE being a TREE_LIST with TREE_PURPOSE the value to be
5823 placed into DECL_OFFSET_ALIGN and TREE_VALUE the bit position. GNU_POS is
5824 to be added to the position, GNU_BITPOS to the bit position, OFFSET_ALIGN is
5825 the present value of DECL_OFFSET_ALIGN and GNU_LIST is a list of the entries
5826 so far. */
5828 static tree
5831 {
5832 tree gnu_field;
5837 {
5842 unsigned int our_offset_align
5845 gnu_result
5850 NULL_TREE),
5851 gnu_result);
5854 gnu_result
5857 our_offset_align);
5858 }
5861 }
5862 \f
5863 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
5864 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
5865 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
5866 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
5867 for the size of a field. COMPONENT_P is true if we are being called
5868 to process the Component_Size of GNAT_OBJECT. This is used for error
5869 message handling and to indicate to use the object size of GNU_TYPE.
5870 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
5871 it means that a size of zero should be treated as an unspecified size. */
5873 static tree
5876 {
5877 Node_Id gnat_error_node;
5878 tree type_size
5880 tree size;
5882 /* Find the node to use for errors. */
5889 else
5892 /* Return 0 if no size was specified, either because Esize was not Present or
5893 the specified size was zero. */
5897 /* Get the size as a tree. Give an error if a size was specified, but cannot
5898 be represented as in sizetype. */
5901 {
5906 }
5908 /* Ignore a negative size since that corresponds to our back-annotation.
5909 Also ignore a zero size unless a size clause exists. */
5913 /* The size of objects is always a multiple of a byte. */
5916 {
5920 else
5924 }
5926 /* If this is an integral type or a packed array type, the front-end has
5927 verified the size, so we need not do it here (which would entail
5928 checking against the bounds). However, if this is an aliased object, it
5929 may not be smaller than the type of the object. */
5934 /* If the object is a record that contains a template, add the size of
5935 the template to the specified size. */
5940 /* Modify the size of the type to be that of the maximum size if it has a
5941 discriminant or the size of a thin pointer if this is a fat pointer. */
5947 /* If this is an access type, the minimum size is that given by the smallest
5948 integral mode that's valid for pointers. */
5950 {
5956 ;
5959 }
5961 /* If the size of the object is a constant, the new size must not be
5962 smaller. */
5966 {
5968 post_error_ne_tree
5971 else
5978 post_error_ne_tree_2
5988 }
5991 }
5992 \f
5993 /* Similarly, but both validate and process a value of RM_Size. This
5994 routine is only called for types. */
5996 static void
5998 {
5999 /* Only give an error if a Value_Size clause was explicitly given.
6000 Otherwise, we'd be duplicating an error on the Size clause. */
6001 Node_Id gnat_attr_node
6004 tree size;
6006 /* Get the size as a tree. Do nothing if none was specified, either
6007 because RM_Size was not Present or if the specified size was zero.
6008 Give an error if a size was specified, but cannot be represented as
6009 in sizetype. */
6015 {
6018 gnat_entity);
6021 }
6023 /* Ignore a negative size since that corresponds to our back-annotation.
6024 Also ignore a zero size unless a size clause exists, a Value_Size
6025 clause exists, or this is an integer type, in which case the
6026 front end will have always set it. */
6033 /* If the old size is self-referential, get the maximum size. */
6037 /* If the size of the object is a constant, the new size must not be
6038 smaller (the front end checks this for scalar types). */
6043 {
6045 post_error_ne_tree
6050 }
6052 /* Otherwise, set the RM_Size. */
6063 }
6064 \f
6065 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
6066 If TYPE is the best type, return it. Otherwise, make a new type. We
6067 only support new integral and pointer types. BIASED_P is nonzero if
6068 we are making a biased type. */
6070 static tree
6072 {
6073 tree new_type;
6077 /* If size indicates an error, just return TYPE to avoid propagating the
6078 error. Likewise if it's too large to represent. */
6084 {
6087 /* Only do something if the type is not already the proper size and is
6088 not a packed array type. */
6100 new_type
6112 /* Do something if this is a fat pointer, in which case we
6113 may need to return the thin pointer. */
6115 return
6116 build_pointer_type
6121 /* Only do something if this is a thin pointer, in which case we
6122 may need to return the fat pointer. */
6124 return
6131 }
6134 }
6135 \f
6136 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
6137 a type or object whose present alignment is ALIGN. If this alignment is
6138 valid, return it. Otherwise, give an error and return ALIGN. */
6140 static unsigned int
6142 {
6146 #ifndef MAX_OFILE_ALIGNMENT
6147 #define MAX_OFILE_ALIGNMENT BIGGEST_ALIGNMENT
6148 #endif
6153 /* Don't worry about checking alignment if alignment was not specified
6154 by the source program and we already posted an error for this entity. */
6159 /* Within GCC, an alignment is an integer, so we must make sure a
6160 value is specified that fits in that range. Also, alignments of
6161 more than MAX_OFILE_ALIGNMENT can't be supported. */
6175 else
6179 }
6180 \f
6181 /* Verify that OBJECT, a type or decl, is something we can implement
6182 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
6183 if we require atomic components. */
6185 static void
6187 {
6189 Node_Id gnat_node;
6192 tree size;
6194 /* There are three case of what OBJECT can be. It can be a type, in which
6195 case we take the size, alignment and mode from the type. It can be a
6196 declaration that was indirect, in which case the relevant values are
6197 that of the type being pointed to, or it can be a normal declaration,
6198 in which case the values are of the decl. The code below assumes that
6199 OBJECT is either a type or a decl. */
6201 {
6205 }
6207 {
6211 }
6212 else
6213 {
6217 }
6219 /* Consider all floating-point types atomic and any types that that are
6220 represented by integers no wider than a machine word. */
6227 /* For the moment, also allow anything that has an alignment equal
6228 to its size and which is smaller than a word. */
6236 {
6244 }
6249 else
6252 }
6253 \f
6254 /* Check if FTYPE1 and FTYPE2, two potentially different function type nodes,
6255 have compatible signatures so that a call using one type may be safely
6256 issued if the actual target function type is the other. Return 1 if it is
6257 the case, 0 otherwise, and post errors on the incompatibilities.
6259 This is used when an Ada subprogram is mapped onto a GCC builtin, to ensure
6260 that calls to the subprogram will have arguments suitable for the later
6261 underlying builtin expansion. */
6263 static int
6265 {
6266 /* As of now, we only perform very trivial tests and consider it's the
6267 programmer's responsability to ensure the type correctness in the Ada
6268 declaration, as in the regular Import cases.
6270 Mismatches typically result in either error messages from the builtin
6271 expander, internal compiler errors, or in a real call sequence. This
6272 should be refined to issue diagnostics helping error detection and
6273 correction. */
6275 /* Almost fake test, ensuring a use of each argument. */
6280 }
6281 \f
6282 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new type
6283 with all size expressions that contain F updated by replacing F with R.
6284 This is identical to GCC's substitute_in_type except that it knows about
6285 TYPE_INDEX_TYPE. If F is NULL_TREE, always make a new RECORD_TYPE, even if
6286 nothing has changed. */
6288 tree
6290 {
6292 tree tem;
6295 {
6302 {
6311 SET_TYPE_INDEX_TYPE
6314 }
6321 {
6335 }
6350 /* Don't know how to do these yet. */
6354 {
6368 /* If we had bounded the sizes of T by a constant, bound the sizes of
6369 NEW by the same constant. */
6379 }
6384 {
6385 tree field;
6386 bool changed_field
6393 /* Start out with no fields, make new fields, and chain them
6394 in. If we haven't actually changed the type of any field,
6395 discard everything we've done and return the old type. */
6401 {
6412 /* If this is an internal field and the type of this field is
6413 a UNION_TYPE or RECORD_TYPE with no elements, ignore it. If
6414 the type just has one element, treat that as the field.
6415 But don't do this if we are processing a QUAL_UNION_TYPE. */
6420 {
6425 {
6426 tree next_new_field
6429 /* Make sure omitting the union doesn't change
6430 the layout. */
6433 }
6434 }
6441 /* If the size of the old field was set at a constant,
6442 propagate the size in case the type's size was variable.
6443 (This occurs in the case of a variant or discriminated
6444 record with a default size used as a field of another
6445 record.) */
6454 {
6460 /* Do the substitution inside the qualifier and if we find
6461 that this field will not be present, omit it. */
6466 }
6470 else
6475 /* If this is a qualified type and this field will always be
6476 present, we are done. */
6480 }
6482 /* If this used to be a qualified union type, but we now know what
6483 field will be present, make this a normal union. */
6494 /* If the size was originally a constant use it. */
6497 {
6501 }
6504 }
6508 }
6509 }
6510 \f
6511 /* Return the "RM size" of GNU_TYPE. This is the actual number of bits
6512 needed to represent the object. */
6514 tree
6516 {
6517 /* For integer types, this is the precision. For record types, we store
6518 the size explicitly. For other types, this is just the size. */
6524 /* Return the rm_size of the actual data plus the size of the template. */
6525 return
6535 else
6537 }
6538 \f
6539 /* Return an identifier representing the external name to be used for
6540 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
6541 and the specified suffix. */
6543 tree
6545 {
6552 #ifdef _WIN32
6553 /* A variable using the Stdcall convention (meaning we are running
6554 on a Windows box) live in a DLL. Here we adjust its name to use
6555 the jump-table, the _imp__NAME contains the address for the NAME
6556 variable. */
6557 {
6564 {
6569 }
6570 }
6571 #endif
6574 }
6576 /* Return the name to be used for GNAT_ENTITY. If a type, create a
6577 fully-qualified name, possibly with type information encoding.
6578 Otherwise, return the name. */
6580 tree
6582 {
6585 }
6587 /* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
6588 string, return a new IDENTIFIER_NODE that is the concatenation of
6589 the name in GNU_ID and SUFFIX. */
6591 tree
6593 {
6602 }