| blob | 6a8f23424c5e20198ff22c500e8114e2aff53c6c |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2006, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 2, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License distributed with GNAT; see file COPYING. If not, write *
19 * to the Free Software Foundation, 51 Franklin Street, Fifth Floor, *
20 * Boston, MA 02110-1301, USA. *
21 * *
22 * GNAT was originally developed by the GNAT team at New York University. *
23 * Extensive contributions were provided by Ada Core Technologies Inc. *
24 * *
25 ****************************************************************************/
56 /* Convention_Stdcall should be processed in a specific way on Windows targets
57 only. The macro below is a helper to avoid having to check for a Windows
58 specific attribute throughout this unit. */
60 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
61 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
62 #else
63 #define Has_Stdcall_Convention(E) (0)
64 #endif
66 /* These two variables are used to defer recursively expanding incomplete
67 types while we are processing a record or subprogram type. */
70 static struct incomplete
71 {
73 tree old_type;
74 Entity_Id full_type;
77 /* These two variables are used to defer emission of debug information for
78 nested incomplete record types */
106 /* Given GNAT_ENTITY, an entity in the incoming GNAT tree, return a
107 GCC type corresponding to that entity. GNAT_ENTITY is assumed to
108 refer to an Ada type. */
110 tree
112 {
113 tree gnu_decl;
115 /* The back end never attempts to annotate generic types */
119 /* Convert the ada entity type into a GCC TYPE_DECL node. */
123 }
124 \f
125 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
126 entity, this routine returns the equivalent GCC tree for that entity
127 (an ..._DECL node) and associates the ..._DECL node with the input GNAT
128 defining identifier.
130 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
131 initial value (in GCC tree form). This is optional for variables.
132 For renamed entities, GNU_EXPR gives the object being renamed.
134 DEFINITION is nonzero if this call is intended for a definition. This is
135 used for separate compilation where it necessary to know whether an
136 external declaration or a definition should be created if the GCC equivalent
137 was not created previously. The value of 1 is normally used for a nonzero
138 DEFINITION, but a value of 2 is used in special circumstances, defined in
139 the code. */
141 tree
143 {
144 tree gnu_entity_id;
146 /* Contains the gnu XXXX_DECL tree node which is equivalent to the input
147 GNAT tree. This node will be associated with the GNAT node by calling
148 the save_gnu_tree routine at the end of the `switch' statement. */
150 /* true if we have already saved gnu_decl as a gnat association. */
152 /* Nonzero if we incremented defer_incomplete_level. */
154 /* Nonzero if we incremented defer_debug_level. */
156 /* Nonzero if we incremented force_global. */
158 /* Nonzero if we should check to see if elaborated during processing. */
160 /* Nonzero if we made GNU_DECL and its type here. */
166 Entity_Id gnat_temp;
167 unsigned int esize
177 bool imported_p
182 /* Since a use of an Itype is a definition, process it as such if it
183 is not in a with'ed unit. */
188 {
189 /* Ensure that we are in a subprogram mentioned in the Scope
190 chain of this entity, our current scope is global,
191 or that we encountered a task or entry (where we can't currently
192 accurately check scoping). */
195 {
198 }
202 {
207 gnat_temp
219 && (current_function_decl
221 {
224 }
225 }
227 /* This abort means the entity "gnat_entity" has an incorrect scope,
228 i.e. that its scope does not correspond to the subprogram in which
229 it is declared */
231 }
233 /* If this is entity 0, something went badly wrong. */
236 /* If we've already processed this entity, return what we got last time.
237 If we are defining the node, we should not have already processed it.
238 In that case, we will abort below when we try to save a new GCC tree for
239 this object. We also need to handle the case of getting a dummy type
240 when a Full_View exists. */
243 && (! definition
245 {
252 {
258 }
261 }
263 /* If this is a numeric or enumeral type, or an access type, a nonzero
264 Esize must be specified unless it was specified by the programmer. */
272 /* Likewise, RM_Size must be specified for all discrete and fixed-point
273 types. */
277 /* Get the name of the entity and set up the line number and filename of
278 the original definition for use in any decl we make. */
282 /* If we get here, it means we have not yet done anything with this
283 entity. If we are not defining it here, it must be external,
284 otherwise we should have defined it already. */
291 /* For cases when we are not defining (i.e., we are referencing from
292 another compilation unit) Public entities, show we are at global level
293 for the purpose of computing scopes. Don't do this for components or
294 discriminants since the relevant test is whether or not the record is
295 being defined. But do this for Imported functions or procedures in
296 all cases. */
304 /* Handle any attributes directly attached to the entity. */
308 /* Machine_Attributes on types are expected to be propagated to subtypes.
309 The corresponding Gigi_Rep_Items are only attached to the first subtype
310 though, so we handle the propagation here. */
317 {
319 /* If this is a use of a deferred constant, get its full
320 declaration. */
322 {
327 }
329 /* If we have an external constant that we are not defining,
330 get the expression that is was defined to represent. We
331 may throw that expression away later if it is not a
332 constant.
333 Do not retrieve the expression if it is an aggregate, because
334 in complex instantiation contexts it may not be expanded */
343 /* Ignore deferred constant definitions; they are processed fully in the
344 front-end. For deferred constant references, get the full
345 definition. On the other hand, constants that are renamings are
346 handled like variable renamings. If No_Initialization is set, this is
347 not a deferred constant but a constant whose value is built
348 manually. */
353 {
357 }
360 {
365 }
370 /* We used to special case VMS exceptions here to directly map them to
371 their associated condition code. Since this code had to be masked
372 dynamically to strip off the severity bits, this caused trouble in
373 the GCC/ZCX case because the "type" pointers we store in the tables
374 have to be static. We now don't special case here anymore, and let
375 the regular processing take place, which leaves us with a regular
376 exception data object for VMS exceptions too. The condition code
377 mapping is taken care of by the front end and the bitmasking by the
378 runtime library. */
383 {
384 /* The GNAT record where the component was defined. */
387 /* If the variable is an inherited record component (in the case of
388 extended record types), just return the inherited entity, which
389 must be a FIELD_DECL. Likewise for discriminants.
390 For discriminants of untagged records which have explicit
391 stored discriminants, return the entity for the corresponding
392 stored discriminant. Also use Original_Record_Component
393 if the record has a private extension. */
397 {
398 gnu_decl
403 }
405 /* If the enclosing record has explicit stored discriminants,
406 then it is an untagged record. If the Corresponding_Discriminant
407 is not empty then this must be a renamed discriminant and its
408 Original_Record_Component must point to the corresponding explicit
409 stored discriminant (i.e., we should have taken the previous
410 branch). */
414 {
415 /* A tagged record has no explicit stored discriminants. */
419 gnu_decl
424 }
426 /* If the enclosing record has explicit stored discriminants,
427 then it is an untagged record. If the Corresponding_Discriminant
428 is not empty then this must be a renamed discriminant and its
429 Original_Record_Component must point to the corresponding explicit
430 stored discriminant (i.e., we should have taken the first
431 branch). */
438 /* Otherwise, if we are not defining this and we have no GCC type
439 for the containing record, make one for it. Then we should
440 have made our own equivalent. */
442 {
443 /* ??? If this is in a record whose scope is a protected
444 type and we have an Original_Record_Component, use it.
445 This is a workaround for major problems in protected type
446 handling. */
454 {
455 gnu_decl
461 }
467 }
469 else
470 /* Here we have no GCC type and this is a reference rather than a
471 definition. This should never happen. Most likely the cause is a
472 reference before declaration in the gnat tree for gnat_entity. */
474 }
480 /* Simple variables, loop variables, OUT parameters, and exceptions. */
481 object:
482 {
484 bool const_flag
499 {
503 else
505 }
507 /* Get the type after elaborating the renamed object. */
510 /* If this is a loop variable, its type should be the base type.
511 This is because the code for processing a loop determines whether
512 a normal loop end test can be done by comparing the bounds of the
513 loop against those of the base type, which is presumed to be the
514 size used for computation. But this is not correct when the size
515 of the subtype is smaller than the type. */
519 /* Reject non-renamed objects whose types are unconstrained arrays or
520 any object whose type is a dummy type or VOID_TYPE. */
526 {
529 force_global--;
531 }
533 /* If an alignment is specified, use it if valid. Note that
534 exceptions are objects but don't have alignments. We must do this
535 before we validate the size, since the alignment can affect the
536 size. */
538 {
544 }
546 /* If we are defining the object, see if it has a Size value and
547 validate it if so. If we are not defining the object and a Size
548 clause applies, simply retrieve the value. We don't want to ignore
549 the clause and it is expected to have been validated already. Then
550 get the new type, if any. */
559 {
560 gnu_type
566 }
568 /* If this object has self-referential size, it must be a record with
569 a default value. We are supposed to allocate an object of the
570 maximum size in this case unless it is a constant with an
571 initializing expression, in which case we can get the size from
572 that. Note that the resulting size may still be a variable, so
573 this may end up with an indirect allocation. */
577 {
579 gnu_size
580 = SUBSTITUTE_PLACEHOLDER_IN_EXPR
583 /* We may have no GNU_EXPR because No_Initialization is
584 set even though there's an Expression. */
589 gnu_size
591 (Etype
593 else
594 {
597 }
598 }
600 /* If the size is zero bytes, make it one byte since some linkers have
601 trouble with zero-sized objects. If the object will have a
602 template, that will make it nonzero so don't bother. Also avoid
603 doing that for an object renaming or an object with an address
604 clause, as we would lose useful information on the view size
605 (e.g. for null array slices) and we are not allocating the object
606 here anyway. */
615 /* If this is an atomic object with no specified size and alignment,
616 but where the size of the type is a constant, set the alignment to
617 the lowest power of two greater than the size, or to the
618 biggest meaningful alignment, whichever is smaller. */
622 {
625 BIGGEST_ALIGNMENT))
627 else
632 }
634 /* If the object is set to have atomic components, find the component
635 type and validate it.
637 ??? Note that we ignore Has_Volatile_Components on objects; it's
638 not at all clear what to do in that case. */
641 {
650 }
652 /* Now check if the type of the object allows atomic access. Note
653 that we must test the type, even if this object has size and
654 alignment to allow such access, because we will be going
655 inside the padded record to assign to the object. We could fix
656 this by always copying via an intermediate value, but it's not
657 clear it's worth the effort. */
661 /* If this is an aliased object with an unconstrained nominal subtype,
662 make a type that includes the template. */
666 {
667 tree gnu_fat
670 gnu_type
674 }
676 #ifdef MINIMUM_ATOMIC_ALIGNMENT
677 /* If the size is a constant and no alignment is specified, force
678 the alignment to be the minimum valid atomic alignment. The
679 restriction on constant size avoids problems with variable-size
680 temporaries; if the size is variable, there's no issue with
681 atomic access. Also don't do this for a constant, since it isn't
682 necessary and can interfere with constant replacement. Finally,
683 do not do it for Out parameters since that creates an
684 size inconsistency with In parameters. */
693 #endif
695 /* Make a new type with the desired size and alignment, if needed. */
699 /* Make a volatile version of this object's type if we are to
700 make the object volatile. Note that 13.3(19) says that we
701 should treat other types of objects as volatile as well. */
711 /* Convert the expression to the type of the object except in the
712 case where the object's type is unconstrained or the object's type
713 is a padded record whose field is of self-referential size. In
714 the former case, converting will generate unnecessary evaluations
715 of the CONSTRUCTOR to compute the size and in the latter case, we
716 want to only copy the actual data. */
722 && (CONTAINS_PLACEHOLDER_P
726 /* See if this is a renaming, and handle appropriately depending on
727 what is renamed and in which context. There are three major
728 cases:
730 1/ This is a constant renaming and we can just make an object
731 with what is renamed as its initial value,
733 2/ We can reuse a stabilized version of what is renamed in place
734 of the renaming,
736 3/ If neither 1 or 2 applies, we make the renaming entity a constant
737 pointer to what is being renamed. */
740 {
741 /* If the renamed object had padding, strip off the reference
742 to the inner object and reset our type. */
746 && (TYPE_IS_PADDING_P
748 {
751 }
753 /* Case 1: If this is a constant renaming, treat it as a normal
754 object whose initial value is what is being renamed. We cannot
755 do this if the type is unconstrained or class-wide. */
762 ;
764 /* Otherwise, see if we can proceed with a stabilized version of
765 the renamed entity or if we need to make a pointer. */
766 else
767 {
771 /* Case 2: If the renaming entity need not be materialized and
772 the renamed expression is something we can stabilize, use
773 that for the renaming. At the global level, we can only do
774 this if we know no SAVE_EXPRs need be made, because the
775 expression we return might be used in arbitrary conditional
776 branches so we must force the SAVE_EXPRs evaluation
777 immediately and this requires a function context. */
782 {
783 maybe_stable_expr
788 {
793 }
795 /* The stabilization failed. Keep maybe_stable_expr
796 untouched here to let the pointer case below know
797 about that failure. */
798 }
800 /* Case 3: Make this into a constant pointer to the object we
801 are to rename and attach the object to the pointer if it is
802 an lvalue that can be stabilized.
804 From the proper scope, attached objects will be referenced
805 directly instead of indirectly via the pointer to avoid
806 subtle aliasing problems with non addressable entities.
807 They have to be stable because we must not evaluate the
808 variables in the expression every time the renaming is used.
809 They also have to be lvalues because the context in which
810 they are reused sometimes requires so. We call pointers
811 with an attached object "renaming" pointers.
813 In the rare cases where we cannot stabilize the renamed
814 object, we just make a "bare" pointer, and the renamed
815 entity is always accessed indirectly through it. */
816 {
823 /* If a previous attempt at unrestricted stabilization
824 failed, there is no point trying again and we can reuse
825 the result without attaching it to the pointer. */
827 ;
829 /* Otherwise, try to stabilize now, restricting to
830 lvalues only, and attach the expression to the pointer
831 if the stabilization succeeds.
833 Note that this might introduce SAVE_EXPRs and we don't
834 check whether we're at the global level or not. This is
835 fine since we are building a pointer initializer and
836 neither the pointer nor the initializing expression can
837 be accessed before the pointer elaboration has taken
838 place in a correct program.
840 SAVE_EXPRs will be evaluated at the right spots by either
841 create_var_decl->expand_decl_init for the non-global case
842 or build_unit_elab for the global case, and will be
843 attached to the elaboration procedure by the RTL expander
844 in the latter case. We have no need to force an early
845 evaluation here. */
846 else
847 {
848 maybe_stable_expr
854 /* Attaching is actually performed downstream, as soon
855 as we have a DECL for the pointer we make. */
856 }
858 gnu_expr
861 /* If the initial expression has side effects, we might
862 still have an unstabilized version at this point (for
863 instance if it involves a function call). Wrap the
864 result into a SAVE_EXPR now, in case it happens to be
865 referenced several times. */
871 }
872 }
873 }
875 /* If this is an aliased object whose nominal subtype is unconstrained,
876 the object is a record that contains both the template and
877 the object. If there is an initializer, it will have already
878 been converted to the right type, but we need to create the
879 template if there is no initializer. */
882 /* Beware that padding might have been introduced
883 via maybe_pad_type above. */
886 == RECORD_TYPE
887 && TYPE_CONTAINS_TEMPLATE_P
890 {
891 tree template_field
896 gnu_expr
897 = gnat_build_constructor
899 tree_cons
903 NULL_TREE),
904 NULL_TREE));
905 }
907 /* If this is a pointer and it does not have an initializing
908 expression, initialize it to NULL, unless the object is
909 imported. */
915 /* If we are defining the object and it has an Address clause we must
916 get the address expression from the saved GCC tree for the
917 object if the object has a Freeze_Node. Otherwise, we elaborate
918 the address expression here since the front-end has guaranteed
919 in that case that the elaboration has no effects. Note that
920 only the latter mechanism is currently in use. */
922 {
923 tree gnu_address
929 /* Ignore the size. It's either meaningless or was handled
930 above. */
937 /* If we don't have an initializing expression for the underlying
938 variable, the initializing expression for the pointer is the
939 specified address. Otherwise, we have to make a COMPOUND_EXPR
940 to assign both the address and the initial value. */
943 else
944 gnu_expr
946 build_binary_op
949 gnu_address),
950 gnu_expr),
951 gnu_address);
952 }
954 /* If it has an address clause and we are not defining it, mark it
955 as an indirect object. Likewise for Stdcall objects that are
956 imported. */
960 {
965 /* No point in taking the address of an initializing expression
966 that isn't going to be used. */
969 }
971 /* If we are at top level and this object is of variable size,
972 make the actual type a hidden pointer to the real type and
973 make the initializer be a memory allocation and initialization.
974 Likewise for objects we aren't defining (presumed to be
975 external references from other packages), but there we do
976 not set up an initialization.
978 If the object's size overflows, make an allocator too, so that
979 Storage_Error gets raised. Note that we will never free
980 such memory, so we presume it never will get allocated. */
985 || (gnu_size
989 {
995 /* In case this was a aliased object whose nominal subtype is
996 unconstrained, the pointer above will be a thin pointer and
997 build_allocator will automatically make the template.
999 If we have a template initializer only (that we made above),
1000 pretend there is none and rely on what build_allocator creates
1001 again anyway. Otherwise (if we have a full initializer), get
1002 the data part and feed that to build_allocator.
1004 If we are elaborating a mutable object, tell build_allocator to
1005 ignore a possibly simpler size from the initializer, if any, as
1006 we must allocate the maximum possible size in this case. */
1009 {
1014 {
1015 gnu_alloc_type
1022 else
1023 gnu_expr
1024 = build_component_ref
1028 }
1034 gnat_entity);
1038 }
1039 else
1040 {
1043 }
1044 }
1046 /* If this object would go into the stack and has an alignment
1047 larger than the default largest alignment, make a variable
1048 to hold the "aligning type" with a modified initial value,
1049 if any, then point to it and make that the value of this
1050 variable, which is now indirect. */
1053 {
1054 tree gnu_new_type
1057 tree gnu_new_var;
1059 gnu_new_var
1065 add_stmt_with_node
1067 build_component_ref
1070 gnu_expr),
1071 gnat_entity);
1074 gnu_expr
1075 = build_unary_op
1083 }
1089 /* Convert the expression to the type of the object except in the
1090 case where the object's type is unconstrained or the object's type
1091 is a padded record whose field is of self-referential size. In
1092 the former case, converting will generate unnecessary evaluations
1093 of the CONSTRUCTOR to compute the size and in the latter case, we
1094 want to only copy the actual data. */
1100 && (CONTAINS_PLACEHOLDER_P
1104 /* If this name is external or there was a name specified, use it,
1105 unless this is a VMS exception object since this would conflict
1106 with the symbol we need to export in addition. Don't use the
1107 Interface_Name if there is an address clause (see CD30005). */
1116 /* If this is constant initialized to a static constant and the
1117 object has an aggregate type, force it to be statically
1118 allocated. */
1134 {
1137 }
1139 /* If we have an address clause and we've made this indirect, it's
1140 not enough to merely mark the type as volatile since volatile
1141 references only conflict with other volatile references while this
1142 reference must conflict with all other references. So ensure that
1143 the dereferenced value has alias set 0. */
1152 STACK_CHECK_MAX_VAR_SIZE))))
1157 gnat_entity);
1159 /* If this is a public constant or we're not optimizing and we're not
1160 making a VAR_DECL for it, make one just for export or debugger
1161 use. Likewise if the address is taken or if the object or type is
1162 aliased. */
1169 {
1170 tree gnu_corr_var
1176 }
1178 /* If this is declared in a block that contains a block with an
1179 exception handler, we must force this variable in memory to
1180 suppress an invalid optimization. */
1185 /* Back-annotate the Alignment of the object if not already in the
1186 tree. Likewise for Esize if the object is of a constant size.
1187 But if the "object" is actually a pointer to an object, the
1188 alignment and size are the same as the type, so don't back-annotate
1189 the values for the pointer. */
1196 {
1201 gnu_back_size
1206 }
1207 }
1211 /* Return a TYPE_DECL for "void" that we previously made. */
1216 /* A special case, for the types Character and Wide_Character in
1217 Standard, we do not list all the literals. So if the literals
1218 are not specified, make this an unsigned type. */
1220 {
1223 }
1225 /* Normal case of non-character type, or non-Standard character type */
1226 {
1227 /* Here we have a list of enumeral constants in First_Literal.
1228 We make a CONST_DECL for each and build into GNU_LITERAL_LIST
1229 the list to be places into TYPE_FIELDS. Each node in the list
1230 is a TREE_LIST node whose TREE_VALUE is the literal name
1231 and whose TREE_PURPOSE is the value of the literal.
1233 Esize contains the number of bits needed to represent the enumeral
1234 type, Type_Low_Bound also points to the first literal and
1235 Type_High_Bound points to the last literal. */
1237 Entity_Id gnat_literal;
1242 else
1250 {
1252 gnu_type);
1253 tree gnu_literal
1261 }
1265 /* Note that the bounds are updated at the end of this function
1266 because to avoid an infinite recursion when we get the bounds of
1267 this type, since those bounds are objects of this type. */
1268 }
1274 /* For integer types, just make a signed type the appropriate number
1275 of bits. */
1280 /* For modular types, make the unsigned type of the proper number of
1281 bits and then set up the modulus, if required. */
1282 {
1284 tree gnu_modulus;
1290 /* Find the smallest mode at least ESIZE bits wide and make a class
1291 using that mode. */
1296 ;
1302 /* Get the modulus in this type. If it overflows, assume it is because
1303 it is equal to 2**Esize. Note that there is no overflow checking
1304 done on unsigned type, so we detect the overflow by looking for
1305 a modulus of zero, which is otherwise invalid. */
1309 {
1314 }
1316 /* If we have to set TYPE_PRECISION different from its natural value,
1317 make a subtype to do do. Likewise if there is a modulus and
1318 it is not one greater than TYPE_MAX_VALUE. */
1322 {
1339 }
1340 }
1349 /* For integral subtypes, we make a new INTEGER_TYPE. Note
1350 that we do not want to call build_range_type since we would
1351 like each subtype node to be distinct. This will be important
1352 when memory aliasing is implemented.
1354 The TREE_TYPE field of the INTEGER_TYPE we make points to the
1355 parent type; this fact is used by the arithmetic conversion
1356 functions.
1358 We elaborate the Ancestor_Subtype if it is not in the current
1359 unit and one of our bounds is non-static. We do this to ensure
1360 consistent naming in the case where several subtypes share the same
1361 bounds by always elaborating the first such subtype first, thus
1362 using its name. */
1374 {
1377 }
1385 gnat_entity,
1392 gnat_entity,
1396 /* One of the above calls might have caused us to be elaborated,
1397 so don't blow up if so. */
1399 {
1402 }
1407 /* This should be an unsigned type if the lower bound is constant
1408 and non-negative or if the base type is unsigned; a signed type
1409 otherwise. */
1419 /* Inherit our alias set from what we're a subtype of. Subtypes
1420 are not different types and a pointer can designate any instance
1421 within a subtype hierarchy. */
1424 /* If the type we are dealing with is to represent a packed array,
1425 we need to have the bits left justified on big-endian targets
1426 and right justified on little-endian targets. We also need to
1427 ensure that when the value is read (e.g. for comparison of two
1428 such values), we only get the good bits, since the unused bits
1429 are uninitialized. Both goals are accomplished by wrapping the
1430 modular value in an enclosing struct. */
1432 {
1434 tree gnu_field;
1443 /* Create a stripped-down declaration of the original type, mainly
1444 for debugging. */
1448 /* Don't notify the field as "addressable", since we won't be taking
1449 it's address and it would prevent create_field_decl from making a
1450 bitfield. */
1459 }
1464 /* If this is a VAX floating-point type, use an integer of the proper
1465 size. All the operations will be handled with ASM statements. */
1467 {
1472 sizetype));
1474 }
1476 /* The type of the Low and High bounds can be our type if this is
1477 a type from Standard, so set them at the end of the function. */
1485 {
1488 }
1490 {
1517 /* One of the above calls might have caused us to be elaborated,
1518 so don't blow up if so. */
1520 {
1523 }
1527 /* Inherit our alias set from what we're a subtype of, as for
1528 integer subtypes. */
1530 }
1533 /* Array and String Types and Subtypes
1535 Unconstrained array types are represented by E_Array_Type and
1536 constrained array types are represented by E_Array_Subtype. There
1537 are no actual objects of an unconstrained array type; all we have
1538 are pointers to that type.
1540 The following fields are defined on array types and subtypes:
1542 Component_Type Component type of the array.
1543 Number_Dimensions Number of dimensions (an int).
1544 First_Index Type of first index. */
1548 {
1554 int firstdim
1556 int nextdim
1562 tree gnu_max_size_unit;
1564 Entity_Id gnat_ind_subtype;
1565 Entity_Id gnat_ind_base_subtype;
1566 tree gnu_template_reference;
1567 tree tem;
1575 /* Make a node for the array. If we are not defining the array
1576 suppress expanding incomplete types. */
1582 /* Build the fat pointer type. Use a "void *" object instead of
1583 a pointer to the array type since we don't have the array type
1584 yet (it will reference the fat pointer via the bounds). */
1587 ptr_void_type_node,
1590 gnu_ptr_template,
1593 /* Make sure we can put this into a register. */
1597 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1598 is the fat pointer. This will be used to access the individual
1599 fields once we build them. */
1603 gnu_template_reference
1607 /* Now create the GCC type for each index and add the fields for
1608 that index to the template. */
1610 gnat_ind_base_subtype
1616 {
1618 tree gnu_ind_subtype
1620 tree gnu_base_subtype
1622 tree gnu_base_min
1624 tree gnu_base_max
1628 /* Make the FIELD_DECLs for the minimum and maximum of this
1629 type and then make extractions of that field from the
1630 template. */
1633 gnu_ind_subtype,
1637 gnu_ind_subtype,
1646 /* We can't use build_component_ref here since the template
1647 type isn't complete yet. */
1650 NULL_TREE);
1653 NULL_TREE);
1656 /* Make a range type with the new ranges, but using
1657 the Ada subtype. Then we convert to sizetype. */
1663 /* Update the maximum size of the array, in elements. */
1664 gnu_max_size
1668 gnu_base_min)));
1672 }
1675 gnu_template_fields
1678 /* Install all the fields into the template. */
1683 /* Now make the array of arrays and update the pointer to the array
1684 in the fat pointer. Note that it is the first field. */
1688 /* Get and validate any specified Component_Size, but if Packed,
1689 ignore it since the front end will have taken care of it. */
1690 gnu_comp_size
1692 gnat_entity,
1700 /* If the component type is a RECORD_TYPE that has a self-referential
1701 size, use the maxium size. */
1707 {
1711 }
1717 /* If Component_Size is not already specified, annotate it with the
1718 size of the component. */
1728 gnu_max_size),
1732 {
1736 /* If the type below this an multi-array type, then this
1737 does not not have aliased components.
1739 ??? Otherwise, for now, we say that any component of aggregate
1740 type is addressable because the front end may take 'Reference
1741 of it. But we have to make it addressable if it must be passed
1742 by reference or it that is the default. */
1748 }
1750 /* If an alignment is specified, use it if valid. But ignore it for
1751 types that represent the unpacked base type for packed arrays. */
1754 {
1759 }
1765 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
1766 corresponding fat pointer. */
1773 /* If the maximum size doesn't overflow, use it. */
1788 /* Create a record type for the object and its template and
1789 set the template at a negative offset. */
1801 /* Give the thin pointer type a name. */
1805 gnat_entity);
1806 }
1812 /* This is the actual data type for array variables. Multidimensional
1813 arrays are implemented in the gnu tree as arrays of arrays. Note
1814 that for the moment arrays which have sparse enumeration subtypes as
1815 index components create sparse arrays, which is obviously space
1816 inefficient but so much easier to code for now.
1818 Also note that the subtype never refers to the unconstrained
1819 array type, which is somewhat at variance with Ada semantics.
1821 First check to see if this is simply a renaming of the array
1822 type. If so, the result is the array type. */
1827 else
1828 {
1831 int first_dim
1834 int next_dim
1836 Entity_Id gnat_ind_subtype;
1837 Entity_Id gnat_ind_base_subtype;
1842 tree gnu_max_size_unit;
1846 /* First create the gnu types for each index. Create types for
1847 debugging information to point to the index types if the
1848 are not integer types, have variable bounds, or are
1849 wider than sizetype. */
1852 gnat_ind_base_subtype
1858 {
1859 tree gnu_index_subtype
1861 tree gnu_min
1863 tree gnu_max
1865 tree gnu_base_subtype
1867 tree gnu_base_min
1869 tree gnu_base_max
1872 tree gnu_base_base_min
1874 tree gnu_base_base_max
1876 tree gnu_high;
1877 tree gnu_this_max;
1879 /* If the minimum and maximum values both overflow in
1880 SIZETYPE, but the difference in the original type
1881 does not overflow in SIZETYPE, ignore the overflow
1882 indications. */
1890 && (!TREE_OVERFLOW
1898 /* Similarly, if the range is null, use bounds of 1..0 for
1899 the sizetype bounds. */
1911 /* Now compute the size of this bound. We need to provide
1912 GCC with an upper bound to use but have to deal with the
1913 "superflat" case. There are three ways to do this. If we
1914 can prove that the array can never be superflat, we can
1915 just use the high bound of the index subtype. If we can
1916 prove that the low bound minus one can't overflow, we
1917 can do this as MAX (hb, lb - 1). Otherwise, we have to use
1918 the expression hb >= lb ? hb : lb - 1. */
1921 /* See if the base array type is already flat. If it is, we
1922 are probably compiling an ACVC test, but it will cause the
1923 code below to malfunction if we don't handle it specially. */
1931 /* If gnu_high is now an integer which overflowed, the array
1932 cannot be superflat. */
1939 else
1940 gnu_high
1941 = build_cond_expr
1949 /* Also compute the maximum size of the array. Here we
1950 see if any constraint on the index type of the base type
1951 can be used in the case of self-referential bound on
1952 the index type of the subtype. We look for a non-"infinite"
1953 and non-self-referential bound from any type involved and
1954 handle each bound separately. */
1979 gnu_this_max
1983 gnu_base_min)),
1984 size_zero_node);
1990 gnu_max_size
2004 }
2006 /* Then flatten: create the array of arrays. */
2010 /* One of the above calls might have caused us to be elaborated,
2011 so don't blow up if so. */
2013 {
2016 }
2018 /* Get and validate any specified Component_Size, but if Packed,
2019 ignore it since the front end will have taken care of it. */
2020 gnu_comp_size
2022 gnat_entity,
2027 /* If the component type is a RECORD_TYPE that has a self-referential
2028 size, use the maxium size. */
2034 {
2039 }
2053 {
2056 /* If the type below this an multi-array type, then this
2057 does not not have aliased components.
2059 ??? Otherwise, for now, we say that any component of aggregate
2060 type is addressable because the front end may take 'Reference
2061 of it. But we have to make it addressable if it must be passed
2062 by reference or it that is the default. */
2068 }
2070 /* If we are at file level and this is a multi-dimensional array, we
2071 need to make a variable corresponding to the stride of the
2072 inner dimensions. */
2074 {
2076 tree gnu_arr_type;
2082 {
2090 /* ??? For now, store the size as a multiple of the
2091 alignment of the element type in bytes so that we
2092 can see the alignment from the tree. */
2094 = build_binary_op
2096 elaborate_expression_1
2105 }
2106 }
2108 /* If we need to write out a record type giving the names of
2109 the bounds, do it now. */
2111 {
2114 tree gnu_field;
2120 {
2121 tree gnu_type_name
2128 integer_type_node,
2129 gnu_bound_rec_type,
2133 }
2137 }
2144 /* If our size depends on a placeholder and the maximum size doesn't
2145 overflow, use it. */
2152 {
2158 }
2160 /* Set our alias set to that of our base type. This gives all
2161 array subtypes the same alias set. */
2163 }
2165 /* If this is a packed type, make this type the same as the packed
2166 array type, but do some adjusting in the type first. */
2169 {
2170 Entity_Id gnat_index;
2171 tree gnu_inner_type;
2173 /* First finish the type we had been making so that we output
2174 debugging information for it */
2175 gnu_type
2178 | (TYPE_QUAL_VOLATILE
2186 /* Save it as our equivalent in case the call below elaborates
2187 this type again. */
2201 /* We need to point the type we just made to our index type so
2202 the actual bounds can be put into a template. */
2208 {
2210 {
2211 /* The TYPE_ACTUAL_BOUNDS field is also used for the modulus.
2212 If it is, we need to make another type. */
2214 {
2215 tree gnu_subtype;
2232 }
2235 }
2241 SET_TYPE_ACTUAL_BOUNDS
2248 SET_TYPE_ACTUAL_BOUNDS
2255 }
2256 }
2258 /* Abort if packed array with no packed array type field set. */
2259 else
2265 /* Create the type for a string literal. */
2266 {
2267 Entity_Id gnat_full_type
2272 tree gnu_string_array_type
2274 tree gnu_string_index_type
2277 tree gnu_lower_bound
2282 tree gnu_upper_bound
2284 gnu_lower_bound,
2286 tree gnu_range_type
2289 tree gnu_index_type
2294 gnu_range_type);
2296 gnu_type
2298 gnu_index_type);
2300 }
2303 /* Record Types and Subtypes
2305 The following fields are defined on record types:
2307 Has_Discriminants True if the record has discriminants
2308 First_Discriminant Points to head of list of discriminants
2309 First_Entity Points to head of list of fields
2310 Is_Tagged_Type True if the record is tagged
2312 Implementation of Ada records and discriminated records:
2314 A record type definition is transformed into the equivalent of a C
2315 struct definition. The fields that are the discriminants which are
2316 found in the Full_Type_Declaration node and the elements of the
2317 Component_List found in the Record_Type_Definition node. The
2318 Component_List can be a recursive structure since each Variant of
2319 the Variant_Part of the Component_List has a Component_List.
2321 Processing of a record type definition comprises starting the list of
2322 field declarations here from the discriminants and the calling the
2323 function components_to_record to add the rest of the fields from the
2324 component list and return the gnu type node. The function
2325 components_to_record will call itself recursively as it traverses
2326 the tree. */
2330 {
2331 gnu_type
2332 = build_complex_type
2333 (get_unpadded_type
2336 (Component_List
2337 (Type_Definition
2341 }
2343 {
2346 Entity_Id gnat_field;
2347 tree gnu_field;
2349 tree gnu_get_parent;
2356 bool is_extension
2360 /* See if all fields have a rep clause. Stop when we find one
2361 that doesn't. */
2370 /* If this is a record extension, go a level further to find the
2371 record definition. Also, verify we have a Parent_Subtype. */
2373 {
2380 }
2382 /* Make a node for the record. If we are not defining the record,
2383 suppress expanding incomplete types. We use the same RECORD_TYPE
2384 as for a dummy type and reset TYPE_DUMMY_P to show it's no longer
2385 a dummy.
2387 It is very tempting to delay resetting this bit until we are done
2388 with completing the type, e.g. to let possible intermediate
2389 elaboration of access types designating the record know it is not
2390 complete and arrange for update_pointer_to to fix things up later.
2392 It would be wrong, however, because dummy types are expected only
2393 to be created for Ada incomplete or private types, which is not
2394 what we have here. Doing so would make other parts of gigi think
2395 we are dealing with a really incomplete or private type, and have
2396 nasty side effects, typically on the generation of the associated
2397 debugging information. */
2410 /* If both a size and rep clause was specified, put the size in
2411 the record type now so that it can get the proper mode. */
2415 /* Always set the alignment here so that it can be used to
2416 set the mode, if it is making the alignment stricter. If
2417 it is invalid, it will be checked again below. If this is to
2418 be Atomic, choose a default alignment of a word unless we know
2419 the size and it's smaller. */
2428 /* If we have a Parent_Subtype, make a field for the parent. If
2429 this record has rep clauses, force the position to zero. */
2431 {
2432 tree gnu_parent;
2434 /* A major complexity here is that the parent subtype will
2435 reference our discriminants. But those must reference
2436 the parent component of this record. So here we will
2437 initialize each of those components to a COMPONENT_REF.
2438 The first operand of that COMPONENT_REF is another
2439 COMPONENT_REF which will be filled in below, once
2440 the parent type can be safely built. */
2445 NULL_TREE),
2446 NULL_TREE);
2453 save_gnu_tree
2457 gnu_get_parent,
2460 NULL_TREE),
2465 gnu_field_list
2475 }
2477 /* Make the fields for the discriminants and put them into the record
2478 unless it's an Unchecked_Union. */
2483 {
2484 /* If this is a record extension and this discriminant
2485 is the renaming of another discriminant, we've already
2486 handled the discriminant above. */
2491 gnu_field
2494 /* Make an expression using a PLACEHOLDER_EXPR from the
2495 FIELD_DECL node just created and link that with the
2496 corresponding GNAT defining identifier. Then add to the
2497 list of fields. */
2506 {
2509 }
2510 }
2512 /* Put the discriminants into the record (backwards), so we can
2513 know the appropriate discriminant to use for the names of the
2514 variants. */
2517 /* Add the listed fields into the record and finish up. */
2524 {
2526 defer_debug_level++;
2528 defer_debug_incomplete_list
2530 defer_debug_incomplete_list);
2531 }
2533 /* We used to remove the associations of the discriminants and
2534 _Parent for validity checking, but we may need them if there's
2535 Freeze_Node for a subtype used in this record. */
2540 /* If it is a tagged record force the type to BLKmode to insure
2541 that these objects will always be placed in memory. Do the
2542 same thing for limited record types. */
2546 /* If this is a derived type, we must make the alias set of this type
2547 the same as that of the type we are derived from. We assume here
2548 that the other type is already frozen. */
2554 /* Fill in locations of fields. */
2557 /* If there are any entities in the chain corresponding to
2558 components that we did not elaborate, ensure we elaborate their
2559 types if they are Itypes. */
2567 }
2571 /* If an equivalent type is present, that is what we should use.
2572 Otherwise, fall through to handle this like a record subtype
2573 since it may have constraints. */
2576 {
2581 }
2583 /* ... fall through ... */
2587 /* If Cloned_Subtype is Present it means this record subtype has
2588 identical layout to that type or subtype and we should use
2589 that GCC type for this one. The front end guarantees that
2590 the component list is shared. */
2592 {
2596 }
2598 /* Otherwise, first ensure the base type is elaborated. Then, if we are
2599 changing the type, make a new type with each field having the
2600 type of the field in the new subtype but having the position
2601 computed by transforming every discriminant reference according
2602 to the constraints. We don't see any difference between
2603 private and nonprivate type here since derivations from types should
2604 have been deferred until the completion of the private type. */
2605 else
2606 {
2608 tree gnu_base_type;
2609 tree gnu_orig_type;
2614 /* Get the base type initially for its alignment and sizes. But
2615 if it is a padded type, we do all the other work with the
2616 unpadded type. */
2625 {
2628 }
2630 /* When the type has discriminants, and these discriminants
2631 affect the shape of what it built, factor them in.
2633 If we are making a subtype of an Unchecked_Union (must be an
2634 Itype), just return the type.
2636 We can't just use Is_Constrained because private subtypes without
2637 discriminants of full types with discriminants with default
2638 expressions are Is_Constrained but aren't constrained! */
2646 {
2647 Entity_Id gnat_field;
2649 tree gnu_pos_list
2652 BIGGEST_ALIGNMENT);
2653 tree gnu_subst_list
2655 definition);
2656 tree gnu_temp;
2662 gnat_entity);
2674 {
2675 tree gnu_old_field
2678 tree gnu_offset
2680 gnu_pos_list));
2683 tree gnu_field_type
2687 unsigned int offset_align
2690 tree gnu_field;
2692 /* If there was a component clause, the field types must be
2693 the same for the type and subtype, so copy the data from
2694 the old field to avoid recomputation here. Also if the
2695 field is justified modular and the optimization in
2696 gnat_to_gnu_field was applied. */
2703 {
2706 }
2708 /* If this was a bitfield, get the size from the old field.
2709 Also ensure the type can be placed into a bitfield. */
2711 {
2717 }
2726 /* If the size is now a constant, we can set it as the
2727 size of the field when we make it. Otherwise, we need
2728 to deal with it specially. */
2732 gnu_field
2733 = create_field_decl
2739 {
2748 bitsize_unit_node));
2750 }
2754 SET_DECL_ORIGINAL_FIELD
2765 }
2767 /* Now go through the entities again looking for Itypes that
2768 we have not elaborated but should (e.g., Etypes of fields
2769 that have Original_Components). */
2780 /* Now set the size, alignment and alias set of the new type to
2781 match that of the old one, doing any substitutions, as
2782 above. */
2808 SET_TYPE_ADA_SIZE
2813 /* Recompute the mode of this record type now that we know its
2814 actual size. */
2817 /* Fill in locations of fields. */
2819 }
2821 /* If we've made a new type, record it and make an XVS type to show
2822 what this is a subtype of. Some debuggers require the XVS
2823 type to be output first, so do it in that order. */
2825 {
2827 {
2838 integer_type_node,
2839 gnu_subtype_marker,
2843 }
2850 }
2852 /* Otherwise, go down all the components in the new type and
2853 make them equivalent to those in the base type. */
2854 else
2861 gnat_to_gnu_field_decl
2863 }
2868 /* If we are not defining this entity, and we have incomplete
2869 entities being processed above us, make a dummy type and
2870 fill it in later. */
2872 {
2876 gnu_type
2877 = build_pointer_type
2890 }
2892 /* ... fall through ... */
2899 {
2901 Entity_Id gnat_desig_full
2903 Incomplete_Or_Private_Kind))
2905 /* We want to know if we'll be seeing the freeze node for any
2906 incomplete type we may be pointing to. */
2907 bool in_main_unit
2923 {
2925 {
2929 }
2931 Incomplete_Or_Private_Kind))
2933 }
2938 /* If either the designated type or its full view is an
2939 unconstrained array subtype, replace it with the type it's a
2940 subtype of. This avoids problems with multiple copies of
2941 unconstrained array types. */
2950 /* If the designated type is a subtype of an incomplete record type,
2951 use the parent type to avoid order of elaboration issues. This
2952 can lose some code efficiency, but there is no alternative. */
2958 /* If we are pointing to an incomplete type whose completion is an
2959 unconstrained array, make a fat pointer type instead of a pointer
2960 to VOID. The two types in our fields will be pointers to VOID and
2961 will be replaced in update_pointer_to. Similarly, if the type
2962 itself is a dummy type or an unconstrained array. Also make
2963 a dummy TYPE_OBJECT_RECORD_TYPE in case we have any thin
2964 pointers to it. */
2980 && defer_incomplete_level
2984 {
2985 tree gnu_old
2989 tree fields;
2991 /* Show the dummy we get will be a fat pointer. */
2994 /* If the call above got something that has a pointer, that
2995 pointer is our type. This could have happened either
2996 because the type was elaborated or because somebody
2997 else executed the code below. */
3000 {
3006 fields
3008 create_field_decl
3013 ptr_void_type_node,
3016 /* Make sure we can place this into a register. */
3027 }
3028 }
3030 /* If we already know what the full type is, use it. */
3035 /* Get the type of the thing we are to point to and build a pointer
3036 to it. If it is a reference to an incomplete or private type with a
3037 full view that is a record, make a dummy type node and get the
3038 actual type later when we have verified it is safe. */
3044 {
3047 }
3049 /* Likewise if we are pointing to a record or array and we are to defer
3050 elaborating incomplete types. We do this since this access type
3051 may be the full view of some private type. Note that the
3052 unconstrained array case is handled above. */
3060 {
3063 }
3065 {
3066 gnu_type
3068 p_mode,
3071 }
3072 else
3075 /* It is possible that the above call to gnat_to_gnu_type resolved our
3076 type. If so, just return it. */
3078 {
3081 }
3083 /* If we have a GCC type for the designated type, possibly modify it
3084 if we are pointing only to constant objects and then make a pointer
3085 to it. Don't do this for unconstrained arrays. */
3087 {
3090 {
3091 gnu_desig_type
3092 = build_qualified_type
3096 /* Some extra processing is required if we are building a
3097 pointer to an incomplete type (in the GCC sense). We might
3098 have such a type if we just made a dummy, or directly out
3099 of the call to gnat_to_gnu_type above if we are processing
3100 an access type for a record component designating the
3101 record type itself. */
3103 {
3104 /* We must ensure that the pointer to variant we make will
3105 be processed by update_pointer_to when the initial type
3106 is completed. Pretend we made a dummy and let further
3107 processing act as usual. */
3110 /* We must ensure that update_pointer_to will not retrieve
3111 the dummy variant when building a properly qualified
3112 version of the complete type. We take advantage of the
3113 fact that get_qualified_type is requiring TYPE_NAMEs to
3114 match to influence build_qualified_type and then also
3115 update_pointer_to here. */
3118 }
3119 }
3121 gnu_type
3124 }
3126 /* If we are not defining this object and we made a dummy pointer,
3127 save our current definition, evaluate the actual type, and replace
3128 the tentative type we made with the actual one. If we are to defer
3129 actually looking up the actual type, make an entry in the
3130 deferred list. */
3133 {
3134 tree gnu_old_type
3140 gnu_type
3141 = build_pointer_type
3142 (TYPE_OBJECT_RECORD_TYPE
3152 /* Note that the call to gnat_to_gnu_type here might have
3153 updated gnu_old_type directly, in which case it is not a
3154 dummy type any more when we get into update_pointer_to.
3156 This may happen for instance when the designated type is a
3157 record type, because their elaboration starts with an
3158 initial node from make_dummy_type, which may yield the same
3159 node as the one we got.
3161 Besides, variants of this non-dummy type might have been
3162 created along the way. update_pointer_to is expected to
3163 properly take care of those situations. */
3166 else
3167 {
3175 }
3176 }
3177 }
3184 else
3185 /* The runtime representation is the equivalent type. */
3199 /* We treat this as identical to its base type; any constraint is
3200 meaningful only to the front end.
3202 The designated type must be elaborated as well, if it does
3203 not have its own freeze node. Designated (sub)types created
3204 for constrained components of records with discriminants are
3205 not frozen by the front end and thus not elaborated by gigi,
3206 because their use may appear before the base type is frozen,
3207 and because it is not clear that they are needed anywhere in
3208 Gigi. With the current model, there is no correct place where
3209 they could be elaborated. */
3216 {
3217 /* If we are not defining this entity, and we have incomplete
3218 entities being processed above us, make a dummy type and
3219 elaborate it later. */
3221 {
3224 tree gnu_ptr_type
3225 = build_pointer_type
3232 }
3235 Incomplete_Or_Private_Kind))
3236 ;
3237 else
3240 }
3245 /* Subprogram Entities
3247 The following access functions are defined for subprograms (functions
3248 or procedures):
3250 First_Formal The first formal parameter.
3251 Is_Imported Indicates that the subprogram has appeared in
3252 an INTERFACE or IMPORT pragma. For now we
3253 assume that the external language is C.
3254 Is_Inlined True if the subprogram is to be inlined.
3256 In addition for function subprograms we have:
3258 Etype Return type of the function.
3260 Each parameter is first checked by calling must_pass_by_ref on its
3261 type to determine if it is passed by reference. For parameters which
3262 are copied in, if they are Ada IN OUT or OUT parameters, their return
3263 value becomes part of a record which becomes the return type of the
3264 function (C function - note that this applies only to Ada procedures
3265 so there is no Ada return type). Additional code to store back the
3266 parameters will be generated on the caller side. This transformation
3267 is done here, not in the front-end.
3269 The intended result of the transformation can be seen from the
3270 equivalent source rewritings that follow:
3272 struct temp {int a,b};
3273 procedure P (A,B: IN OUT ...) is temp P (int A,B) {
3274 .. ..
3275 end P; return {A,B};
3276 }
3277 procedure call
3279 {
3280 temp t;
3281 P(X,Y); t = P(X,Y);
3282 X = t.a , Y = t.b;
3283 }
3285 For subprogram types we need to perform mainly the same conversions to
3286 GCC form that are needed for procedures and function declarations. The
3287 only difference is that at the end, we make a type declaration instead
3288 of a function declaration. */
3293 {
3294 /* The first GCC parameter declaration (a PARM_DECL node). The
3295 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3296 actually is the head of this parameter list. */
3298 /* The type returned by a function. If the subprogram is a procedure
3299 this type should be void_type_node. */
3301 /* List of fields in return type of procedure with copy in copy out
3302 parameters. */
3304 /* Non-null for subprograms containing parameters passed by copy in
3305 copy out (Ada IN OUT or OUT parameters not passed by reference),
3306 in which case it is the list of nodes used to specify the values of
3307 the in out/out parameters that are returned as a record upon
3308 procedure return. The TREE_PURPOSE of an element of this list is
3309 a field of the record and the TREE_VALUE is the PARM_DECL
3310 corresponding to that field. This list will be saved in the
3311 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3313 /* If an import pragma asks to map this subprogram to a GCC builtin,
3314 this is the builtin DECL node. */
3316 Entity_Id gnat_param;
3319 bool extern_flag
3331 /* A parameter may refer to this type, so defer completion
3332 of any incomplete types. */
3335 /* If the subprogram has an alias, it is probably inherited, so
3336 we can use the original one. If the original "subprogram"
3337 is actually an enumeration literal, it may be the first use
3338 of its type, so we must elaborate that type now. */
3340 {
3347 /* Elaborate any Itypes in the parameters of this entity. */
3355 }
3357 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3358 corresponding DECL node.
3360 We still want the parameter associations to take place because the
3361 proper generation of calls depends on it (a GNAT parameter without
3362 a corresponding GCC tree has a very specific meaning), so we don't
3363 just break here. */
3367 /* ??? What if we don't find the builtin node above ? warn ? err ?
3368 In the current state we neither warn nor err, and calls will just
3369 be handled as for regular subprograms. */
3374 /* If this function returns by reference, make the actual
3375 return type of this function the pointer and mark the decl. */
3377 {
3380 }
3382 /* If the Mechanism is By_Reference, ensure the return type uses
3383 the machine's by-reference mechanism, which may not the same
3384 as above (e.g., it might be by passing a fake parameter). */
3387 {
3390 }
3392 /* If we are supposed to return an unconstrained array,
3393 actually return a fat pointer and make a note of that. Return
3394 a pointer to an unconstrained record of variable size. */
3396 {
3399 }
3401 /* If the type requires a transient scope, the result is allocated
3402 on the secondary stack, so the result type of the function is
3403 just a pointer. */
3405 {
3408 }
3410 /* If the type is a padded type and the underlying type would not
3411 be passed by reference or this function has a foreign convention,
3412 return the underlying type. */
3420 /* If the return type is unconstrained, that means it must have a
3421 maximum size. We convert the function into a procedure and its
3422 caller will pass a pointer to an object of that maximum size as the
3423 first parameter when we call the function. */
3425 {
3427 gnu_param_list
3432 }
3434 /* If the return type has a size that overflows, we cannot have
3435 a function that returns that type. This usage doesn't make
3436 sense anyway, so give an error here. */
3440 {
3442 gnat_entity);
3448 }
3450 /* Look at all our parameters and get the type of
3451 each. While doing this, build a copy-out structure if
3452 we need one. */
3457 {
3467 /* Builtins are expanded inline and there is no real call sequence
3468 involved. so the type expected by the underlying expander is
3469 always the type of each argument "as is". */
3473 /* Otherwise, see if a Mechanism was supplied that forced this
3474 parameter to be passed one way or another. */
3478 ;
3486 {
3492 else
3494 }
3495 else
3498 /* If this is either a foreign function or if the
3499 underlying type won't be passed by reference, strip off
3500 possible padding type. */
3506 && (req_by_copy
3508 (TYPE_FIELDS
3512 /* If this is an IN parameter it is read-only, so make a variant
3513 of the type that is read-only.
3515 ??? However, if this is an unconstrained array, that type can
3516 be very complex. So skip it for now. Likewise for any other
3517 self-referential type. */
3521 gnu_param_type
3526 /* For foreign conventions, pass arrays as a pointer to the
3527 underlying type. First check for unconstrained array and get
3528 the underlying array. Then get the component type and build
3529 a pointer to it. */
3532 gnu_param_type
3537 gnu_param_type
3538 = build_pointer_type
3543 && !req_by_copy
3545 {
3546 /* Strip off any multi-dimensional entries, then strip
3547 off the last array to get the component type. */
3556 gnu_param_type
3562 }
3564 /* Fat pointers are passed as thin pointers for foreign
3565 conventions. */
3568 gnu_param_type
3572 /* If we must pass or were requested to pass by reference, do so.
3573 If we were requested to pass by copy, do so.
3574 Otherwise, for foreign conventions, pass all in out parameters
3575 or aggregates by reference. For COBOL and Fortran, pass
3576 all integer and FP types that way too. For Convention Ada,
3577 use the standard Ada default. */
3579 || (!req_by_copy
3589 /* For convention Ada, see if we pass by reference
3590 by default. */
3593 {
3596 }
3604 /* If this is an OUT parameter that isn't passed by reference
3605 and isn't a pointer or aggregate, we don't make a PARM_DECL
3606 for it. Instead, it will be a VAR_DECL created when we process
3607 the procedure. For the special parameter of Valued_Procedure,
3608 never pass it in.
3610 An exception is made to cover the RM-6.4.1 rule requiring "by
3611 copy" out parameters with discriminants or implicit initial
3612 values to be handled like in out parameters. These type are
3613 normally built as aggregates, and hence passed by reference,
3614 except for some packed arrays which end up encoded in special
3615 integer types.
3617 The exception we need to make is then for packed arrays of
3618 records with discriminants or implicit initial values. We have
3619 no light/easy way to check for the latter case, so we merely
3620 check for packed arrays of records. This may lead to useless
3621 copy-in operations, but in very rare cases only, as these would
3622 be exceptions in a set of already exceptional situations. */
3625 || (!by_descr_p
3633 else
3634 {
3635 gnu_param
3636 = create_param_decl
3638 by_ref_p || by_component_ptr_p
3652 /* If a parameter is a pointer, this function may modify
3653 memory through it and thus shouldn't be considered
3654 a pure function. Also, the memory may be modified
3655 between two calls, so they can't be CSE'ed. The latter
3656 case also handles by-ref parameters. */
3660 }
3663 {
3665 {
3670 }
3679 gnu_return_list);
3680 }
3681 }
3683 /* Do not compute record for out parameters if subprogram is
3684 stubbed since structures are incomplete for the back-end. */
3687 {
3688 /* If all types are not complete, defer emission of debug
3689 information for this record types. Otherwise, we risk emitting
3690 debug information for a dummy type contained in the fields
3691 for that record. */
3696 {
3698 defer_debug_level++;
3700 defer_debug_incomplete_list
3702 defer_debug_incomplete_list);
3703 }
3704 }
3706 /* If we have a CICO list but it has only one entry, we convert
3707 this function into a function that simply returns that one
3708 object. */
3713 {
3723 }
3725 /* Both lists ware built in reverse. */
3729 gnu_type
3732 returns_by_ref,
3734 returns_by_target_ptr);
3736 /* A subprogram (something that doesn't return anything) shouldn't
3737 be considered Pure since there would be no reason for such a
3738 subprogram. Note that procedures with Out (or In Out) parameters
3739 have already been converted into a function with a return type. */
3743 gnu_type
3751 /* If we have a builtin decl for that function, check the signatures
3752 compatibilities. If the signatures are compatible, use the builtin
3753 decl. If they are not, we expect the checker predicate to have
3754 posted the appropriate errors, and just continue with what we have
3755 so far. */
3757 {
3761 {
3765 }
3766 }
3768 /* If there was no specified Interface_Name and the external and
3769 internal names of the subprogram are the same, only use the
3770 internal name to allow disambiguation of nested subprograms. */
3774 /* If we are defining the subprogram and it has an Address clause
3775 we must get the address expression from the saved GCC tree for the
3776 subprogram if it has a Freeze_Node. Otherwise, we elaborate
3777 the address expression here since the front-end has guaranteed
3778 in that case that the elaboration has no effects. If there is
3779 an Address clause and we are not defining the object, just
3780 make it a constant. */
3782 {
3786 gnu_address
3797 gnu_decl
3802 }
3808 gnat_entity);
3809 else
3810 {
3815 gnat_entity);
3818 }
3819 }
3830 /* If this type does not have a full view in the unit we are
3831 compiling, then just get the type from its Etype. */
3833 {
3834 /* If this is an incomplete type with no full view, it must be
3835 either a limited view brought in by a limited_with clause, in
3836 which case we use the non-limited view, or a Taft Amendement
3837 type, in which case we just return a dummy type. */
3839 {
3844 else
3846 }
3851 else
3852 {
3856 }
3859 }
3861 /* Otherwise, if we are not defining the type now, get the
3862 type from the full view. But always get the type from the full
3863 view for define on use types, since otherwise we won't see them! */
3870 {
3875 }
3877 /* For incomplete types, make a dummy type entry which will be
3878 replaced later. */
3881 /* Save this type as the full declaration's type so we can do any needed
3882 updates when we see it. */
3889 /* Simple class_wide types are always viewed as their root_type
3890 by Gigi unless an Equivalent_Type is specified. */
3894 else
3906 else
3918 /* Nothing at all to do here, so just return an ERROR_MARK and claim
3919 we've already saved it, so we don't try to. */
3926 }
3928 /* If we had a case where we evaluated another type and it might have
3929 defined this one, handle it here. */
3931 {
3934 }
3936 /* If we are processing a type and there is either no decl for it or
3937 we just made one, do some common processing for the type, such as
3938 handling alignment and possible padding. */
3941 {
3949 /* ??? Don't set the size for a String_Literal since it is either
3950 confirming or we don't handle it properly (if the low bound is
3951 non-constant). */
3957 /* If a size was specified, see if we can make a new type of that size
3958 by rearranging the type, for example from a fat to a thin pointer. */
3960 {
3961 gnu_type
3968 }
3970 /* If the alignment hasn't already been processed and this is
3971 not an unconstrained array, see if an alignment is specified.
3972 If not, we pick a default alignment for atomic objects. */
3974 ;
3988 /* See if we need to pad the type. If we did, and made a record,
3989 the name of the new type may be changed. So get it back for
3990 us when we make the new TYPE_DECL below. */
3995 {
3999 }
4003 /* If we are at global level, GCC will have applied variable_size to
4004 the type, but that won't have done anything. So, if it's not
4005 a constant or self-referential, call elaborate_expression_1 to
4006 make a variable for the size rather than calculating it each time.
4007 Handle both the RM size and the actual size. */
4012 {
4016 {
4023 }
4024 else
4025 {
4032 /* ??? For now, store the size as a multiple of the alignment
4033 in bytes so that we can see the alignment from the tree. */
4035 = build_binary_op
4037 elaborate_expression_1
4048 SET_TYPE_ADA_SIZE
4051 gnat_entity,
4055 }
4056 }
4058 /* If this is a record type or subtype, call elaborate_expression_1 on
4059 any field position. Do this for both global and local types.
4060 Skip any fields that we haven't made trees for to avoid problems with
4061 class wide types. */
4066 {
4069 /* ??? Unfortunately, GCC needs to be able to prove the
4070 alignment of this offset and if it's a variable, it can't.
4071 In GCC 3.4, we'll use DECL_OFFSET_ALIGN in some way, but
4072 right now, we have to put in an explicit multiply and
4073 divide by that value. */
4076 = build_binary_op
4078 elaborate_expression_1
4087 }
4091 | (TYPE_QUAL_VOLATILE
4104 else
4106 }
4109 {
4112 /* Back-annotate the Alignment of the type if not already in the
4113 tree. Likewise for sizes. */
4119 {
4120 /* If the size is self-referential, we annotate the maximum
4121 value of that size. */
4130 {
4131 /* In this mode the tag and the parent components are not
4132 generated by the front-end, so the sizes must be adjusted
4133 explicitly now. */
4139 {
4140 size_offset
4144 }
4145 else
4153 }
4154 }
4158 }
4168 /* If we haven't already, associate the ..._DECL node that we just made with
4169 the input GNAT entity node. */
4173 /* If this is an enumeral or floating-point type, we were not able to set
4174 the bounds since they refer to the type. These bounds are always static.
4176 For enumeration types, also write debugging information and declare the
4177 enumeration literal table, if needed. */
4181 {
4184 /* If this is a padded type, we need to use the underlying type. */
4189 /* If this is a floating point type and we haven't set a floating
4190 point type yet, use this in the evaluation of the bounds. */
4200 {
4203 /* Since this has both a typedef and a tag, avoid outputting
4204 the name twice. */
4207 }
4208 }
4210 /* If we deferred processing of incomplete types, re-enable it. If there
4211 were no other disables and we have some to process, do so. */
4213 {
4219 {
4226 }
4227 }
4229 /* If we are not defining this type, see if it's in the incomplete list.
4230 If so, handle that list entry now. */
4232 {
4237 {
4241 }
4242 }
4244 /* If there are no incomplete types and we have deferred emission
4245 of debug information, check whether we have finished defining
4246 all nested records.
4247 If so, handle the list now. */
4250 defer_debug_level--;
4253 && !defer_incomplete_level
4255 {
4261 {
4264 }
4267 }
4270 force_global--;
4279 }
4281 /* Similar, but if the returned value is a COMPONENT_REF, return the
4282 FIELD_DECL. */
4284 tree
4286 {
4293 }
4294 \f
4295 /* Given GNAT_ENTITY, elaborate all expressions that are required to
4296 be elaborated at the point of its definition, but do nothing else. */
4298 void
4300 {
4302 {
4309 {
4313 /* ??? Tests for avoiding static constraint error expression
4314 is needed until the front stops generating bogus conversions
4315 on bounds of real types. */
4324 }
4327 {
4331 /* If this is a record extension, go a level further to find the
4332 record definition. */
4335 }
4345 {
4346 Node_Id gnat_discriminant_expr;
4347 Entity_Id gnat_field;
4350 gnat_discriminant_expr
4355 /* ??? For now, ignore access discriminants. */
4358 gnat_entity,
4360 }
4363 }
4364 }
4365 \f
4366 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
4367 any entities on its entity chain similarly. */
4369 void
4371 {
4372 Entity_Id gnat_sub_entity;
4375 /* If this has an entity list, process all in the list. */
4392 /* Now clear this if it has been defined, but only do so if it isn't
4393 a subprogram or parameter. We could refine this, but it isn't
4394 worth it. If this is statically allocated, it is supposed to
4395 hang around out of cope. */
4398 {
4401 }
4402 }
4403 \f
4404 /* Set the alias set of GNU_NEW_TYPE to be that of GNU_OLD_TYPE. If this
4405 is a multi-dimensional array type, do this recursively. */
4407 static void
4409 {
4410 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
4411 of a one-dimensional array, since the padding has the same alias set
4412 as the field type, but if it's a multi-dimensional array, we need to
4413 see the inner types. */
4419 /* We need to be careful here in case GNU_OLD_TYPE is an unconstrained
4420 array. In that case, it doesn't have the same shape as GNU_NEW_TYPE,
4421 so we need to go down to what does. */
4423 gnu_old_type
4433 }
4434 \f
4435 /* Return a TREE_LIST describing the substitutions needed to reflect
4436 discriminant substitutions from GNAT_SUBTYPE to GNAT_TYPE and add
4437 them to GNU_LIST. If GNAT_TYPE is not specified, use the base type
4438 of GNAT_SUBTYPE. The substitutions can be in any order. TREE_PURPOSE
4439 gives the tree for the discriminant and TREE_VALUES is the replacement
4440 value. They are in the form of operands to substitute_in_expr.
4441 DEFINITION is as in gnat_to_gnu_entity. */
4443 static tree
4446 {
4447 Entity_Id gnat_discrim;
4448 Node_Id gnat_value;
4459 /* Ignore access discriminants. */
4462 elaborate_expression
4466 gnu_list);
4469 }
4470 \f
4471 /* For the following two functions: for each GNAT entity, the GCC
4472 tree node used as a dummy for that entity, if any. */
4476 /* Initialize the above table. */
4478 void
4480 {
4481 Node_Id gnat_node;
4489 }
4491 /* Make a dummy type corresponding to GNAT_TYPE. */
4493 tree
4495 {
4496 Entity_Id gnat_underlying;
4497 tree gnu_type;
4500 /* Find a full type for GNAT_TYPE, taking into account any class wide
4501 types. */
4511 ;
4513 /* If it there already a dummy type, use that one. Else make one. */
4517 /* If this is a record, make this a RECORD_TYPE or UNION_TYPE; else make
4518 it an ENUMERAL_TYPE. */
4520 {
4521 Node_Id component_list
4523 (Declaration_Node
4525 Node_Id component;
4527 /* Make this a UNION_TYPE unless it's either not an Unchecked_Union or
4528 we have a non-discriminant field outside a variant. In either case,
4529 it's a RECORD_TYPE. */
4533 else
4538 }
4539 else
4551 }
4552 \f
4553 /* Return true if the size represented by GNU_SIZE can be handled by an
4554 allocation. If STATIC_P is true, consider only what can be done with a
4555 static allocation. */
4557 static bool
4559 {
4560 HOST_WIDE_INT our_size;
4562 /* If this is not a static allocation, the only case we want to forbid
4563 is an overflowing size. That will be converted into a raise a
4564 Storage_Error. */
4569 /* Otherwise, we need to deal with both variable sizes and constant
4570 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
4571 since assemblers may not like very large sizes. */
4577 }
4578 \f
4579 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
4581 static void
4583 {
4584 Node_Id gnat_temp;
4589 {
4599 {
4601 (gnat_to_gnu
4608 (gnat_to_gnu
4609 (Expression
4612 }
4615 {
4642 }
4649 /* If we have an argument specified together with an attribute name,
4650 make it a single TREE_VALUE entry in a list of arguments, as GCC
4651 expects it. */
4654 else
4657 attr->error_point
4661 }
4662 }
4663 \f
4664 /* Get the unpadded version of a GNAT type. */
4666 tree
4668 {
4675 }
4676 \f
4677 /* Called when we need to protect a variable object using a save_expr. */
4679 tree
4681 {
4688 {
4696 }
4697 else
4699 }
4700 \f
4701 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
4702 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
4703 return the GCC tree to use for that expression. GNU_NAME is the
4704 qualification to use if an external name is appropriate and DEFINITION is
4705 nonzero if this is a definition of GNAT_ENTITY. If NEED_VALUE is nonzero,
4706 we need a result. Otherwise, we are just elaborating this for
4707 side-effects. If NEED_DEBUG is nonzero we need the symbol for debugging
4708 purposes even if it isn't needed for code generation. */
4710 static tree
4714 {
4715 tree gnu_expr;
4717 /* If we already elaborated this expression (e.g., it was involved
4718 in the definition of a private type), use the old value. */
4722 /* If we don't need a value and this is static or a discriminant, we
4723 don't need to do anything. */
4730 /* Otherwise, convert this tree to its GCC equivalent. */
4731 gnu_expr
4735 /* Save the expression in case we try to elaborate this entity again. Since
4736 this is not a DECL, don't check it. Don't save if it's a discriminant. */
4741 }
4743 /* Similar, but take a GNU expression. */
4745 static tree
4749 {
4751 /* Strip any conversions to see if the expression is a readonly variable.
4752 ??? This really should remain readonly, but we have to think about
4753 the typing of the tree here. */
4758 /* In most cases, we won't see a naked FIELD_DECL here because a
4759 discriminant reference will have been replaced with a COMPONENT_REF
4760 when the type is being elaborated. However, there are some cases
4761 involving child types where we will. So convert it to a COMPONENT_REF
4762 here. We have to hope it will be at the highest level of the
4763 expression in these cases. */
4769 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
4770 that is a constant, make a variable that is initialized to contain the
4771 bound when the package containing the definition is elaborated. If
4772 this entity is defined at top level and a bound or discriminant value
4773 isn't a constant or a reference to a discriminant, replace the bound
4774 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
4775 rely here on the fact that an expression cannot contain both the
4776 discriminant and some other variable. */
4783 /* If this is a static expression or contains a discriminant, we don't
4784 need the variable for debugging (and can't elaborate anyway if a
4785 discriminant). */
4791 /* Now create the variable if we need it. */
4793 gnu_decl
4800 /* We only need to use this variable if we are in global context since GCC
4801 can do the right thing in the local case. */
4806 else
4808 }
4809 \f
4810 /* Create a record type that contains a field of TYPE with a starting bit
4811 position so that it is aligned to ALIGN bits and is SIZE bytes long. */
4813 tree
4815 {
4820 place));
4829 /* The bit position is obtained by "and"ing the alignment minus 1
4830 with the two's complement of the address and multiplying
4831 by the number of bits per unit. Do all this in sizetype. */
4836 size_addr_place),
4839 bitsize_unit_node);
4841 /* Create the field, with -1 as the 'addressable' indication to avoid the
4842 creation of a bitfield. We don't need one, it would have damaging
4843 consequences on the alignment computation, and create_field_decl would
4844 make one without this special argument, for instance because of the
4845 complex position expression. */
4854 bitsize_unit_node),
4860 }
4861 \f
4862 /* TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE, with BLKmode that's
4863 being used as the field type of a packed record. See if we can rewrite it
4864 as a record that has a non-BLKmode type, which we can pack tighter. If so,
4865 return the new type. If not, return the original type. */
4867 static tree
4869 {
4872 tree old_field;
4874 /* Copy the name and flags from the old type to that of the new and set
4875 the alignment to try for an integral type. For QUAL_UNION_TYPE,
4876 also copy the size. */
4885 {
4888 }
4894 /* Now copy the fields, keeping the position and size. */
4897 {
4899 tree new_field;
4915 SET_DECL_ORIGINAL_FIELD
4924 }
4929 }
4930 \f
4931 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
4932 if needed. We have already verified that SIZE and TYPE are large enough.
4934 GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
4935 to issue a warning.
4937 IS_USER_TYPE is true if we must be sure we complete the original type.
4939 DEFINITION is true if this type is being defined.
4941 SAME_RM_SIZE is true if the RM_Size of the resulting type is to be
4942 set to its TYPE_SIZE; otherwise, it's set to the RM_Size of the original
4943 type. */
4945 tree
4949 {
4951 tree record;
4952 tree field;
4954 /* If TYPE is a padded type, see if it agrees with any size and alignment
4955 we were given. If so, return the original type. Otherwise, strip
4956 off the padding, since we will either be returning the inner type
4957 or repadding it. If no size or alignment is specified, use that of
4958 the original padded type. */
4961 {
4978 }
4980 /* If the size is either not being changed or is being made smaller (which
4981 is not done here (and is only valid for bitfields anyway), show the size
4982 isn't changing. Likewise, clear the alignment if it isn't being
4983 changed. Then return if we aren't doing anything. */
4997 /* We used to modify the record in place in some cases, but that could
4998 generate incorrect debugging information. So make a new record
4999 type and name. */
5005 /* If we were making a type, complete the original type and give it a
5006 name. */
5013 gnat_entity);
5015 /* If we are changing the alignment and the input type is a record with
5016 BLKmode and a small constant size, try to make a form that has an
5017 integral mode. That might allow this record to have an integral mode,
5018 which will be much more efficient. There is no point in doing this if a
5019 size is specified unless it is also smaller than the biggest alignment
5020 and it is incorrect to do this if the size of the original type is not a
5021 multiple of the alignment. */
5027 && (!size
5049 /* Keep the RM_Size of the padded record as that of the old record
5050 if requested. */
5053 /* Unless debugging information isn't being written for the input type,
5054 write a record that shows what we are a subtype of and also make a
5055 variable that indicates our size, if variable. */
5059 {
5080 }
5087 /* If the size was widened explicitly, maybe give a warning. */
5093 {
5106 /* Generate message only for entities that come from source, since
5107 if we have an entity created by expansion, the message will be
5108 generated for some other corresponding source entity. */
5111 gnat_entity,
5118 }
5121 }
5122 \f
5123 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
5124 the value passed against the list of choices. */
5126 tree
5128 {
5129 Node_Id choice;
5130 Node_Id gnat_temp;
5135 {
5137 {
5142 /* There's no good type to use here, so we might as well use
5143 integer_type_node. */
5144 this_test
5158 this_test
5168 /* This represents either a subtype range, an enumeration
5169 literal, or a constant Ekind says which. If an enumeration
5170 literal or constant, fall through to the next case. */
5173 {
5179 this_test
5186 }
5187 /* ... fall through ... */
5192 single);
5201 }
5205 }
5208 }
5209 \f
5210 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
5211 placed in GNU_RECORD_TYPE.
5213 PACKED is 1 if the enclosing record is packed and -1 if the enclosing
5214 record has a Component_Alignment of Storage_Unit.
5216 DEFINITION is true if this field is for a record being defined. */
5218 static tree
5221 {
5226 tree gnu_field;
5227 bool needs_strict_alignment
5231 /* If this field requires strict alignment or contains an item of
5232 variable sized, pretend it isn't packed. */
5236 /* For packed records, this is one of the few occasions on which we use
5237 the official RM size for discrete or fixed-point components, instead
5238 of the normal GNAT size stored in Esize. See description in Einfo:
5239 "Handling of Type'Size Values" for further details. */
5249 /* If we have a specified size that's smaller than that of the field type,
5250 or a position is specified, and the field type is also a record that's
5251 BLKmode and with a small constant size, see if we can get an integral
5252 mode form of the type when appropriate. If we can, show a size was
5253 specified for the field if there wasn't one already, so we know to make
5254 this a bitfield and avoid making things wider.
5256 Doing this is first useful if the record is packed because we can then
5257 place the field at a non-byte-aligned position and so achieve tighter
5258 packing.
5260 This is in addition *required* if the field shares a byte with another
5261 field and the front-end lets the back-end handle the references, because
5262 GCC does not handle BLKmode bitfields properly.
5264 We avoid the transformation if it is not required or potentially useful,
5265 as it might entail an increase of the field's alignment and have ripple
5266 effects on the outer record type. A typical case is a field known to be
5267 byte aligned and not to share a byte with another field.
5269 Besides, we don't even look the possibility of a transformation in cases
5270 known to be in error already, for instance when an invalid size results
5271 from a component clause. */
5278 || (gnu_size
5281 {
5282 /* See what the alternate type and size would be. */
5285 bool has_byte_aligned_clause
5290 /* Compute whether we should avoid the substitution. */
5292 /* There is no point substituting if there is no change. */
5294 ||
5295 /* ... nor when the field is known to be byte aligned and not to
5296 share a byte with another field. */
5297 (has_byte_aligned_clause
5299 ||
5300 /* The size of an aliased field must be an exact multiple of the
5301 type's alignment, which the substitution might increase. Reject
5302 substitutions that would so invalidate a component clause when the
5303 specified position is byte aligned, as the change would have no
5304 real benefit from the packing standpoint anyway. */
5306 && has_byte_aligned_clause
5308 );
5310 /* Substitute unless told otherwise. */
5312 {
5317 }
5318 }
5320 /* If we are packing the record and the field is BLKmode, round the
5321 size up to a byte boundary. */
5326 {
5331 /* Ensure the position does not overlap with the parent subtype,
5332 if there is one. */
5334 {
5335 tree gnu_parent
5341 {
5342 post_error_ne_tree
5346 }
5347 }
5349 /* If this field needs strict alignment, ensure the record is
5350 sufficiently aligned and that that position and size are
5351 consistent with the alignment. */
5353 {
5360 /* If Atomic, the size must match exactly that of the field. */
5363 {
5364 post_error_ne_tree
5370 }
5372 /* If Aliased, the size must match exactly the rounded size. We
5373 used to be more accommodating here and accept greater sizes, but
5374 fully supporting this case on big-endian platforms would require
5375 switching to a more involved layout for the field. */
5377 && gnu_size
5379 {
5380 post_error_ne_tree
5383 gnu_rounded_size);
5385 }
5390 {
5392 post_error_ne_num
5398 post_error_ne_num
5404 post_error_ne_num
5408 else
5412 }
5413 }
5417 }
5419 /* If the record has rep clauses and this is the tag field, make a rep
5420 clause for it as well. */
5423 {
5426 }
5428 /* We need to make the size the maximum for the type if it is
5429 self-referential and an unconstrained type. In that case, we can't
5430 pack the field since we can't make a copy to align it. */
5432 && !gnu_size
5435 {
5438 }
5440 /* If no size is specified (or if there was an error), don't specify a
5441 position. */
5444 else
5445 {
5446 /* If the field's type is justified modular, we would need to remove
5447 the wrapper to (better) meet the layout requirements. However we
5448 can do so only if the field is not aliased to preserve the unique
5449 layout and if the prescribed size is not greater than that of the
5450 packed array to preserve the justification. */
5458 gnu_field_type
5463 }
5468 /* Now create the decl for the field. */
5480 }
5481 \f
5482 /* Return true if TYPE is a type with variable size, a padding type with a
5483 field of variable size or is a record that has a field such a field. */
5485 static bool
5487 {
5488 tree field;
5490 /* We need not be concerned about this at all if we don't have
5491 strict alignment. */
5509 }
5510 \f
5511 /* Return a GCC tree for a record type given a GNAT Component_List and a chain
5512 of GCC trees for fields that are in the record and have already been
5513 processed. When called from gnat_to_gnu_entity during the processing of a
5514 record type definition, the GCC nodes for the discriminants will be on
5515 the chain. The other calls to this function are recursive calls from
5516 itself for the Component_List of a variant and the chain is empty.
5518 PACKED is 1 if this is for a record with "pragma pack" and -1 is this is
5519 for a record type with "pragma component_alignment (storage_unit)".
5521 DEFINITION is true if we are defining this record.
5523 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
5524 with a rep clause is to be added. If it is nonzero, that is all that
5525 should be done with such fields.
5527 CANCEL_ALIGNMENT, if true, means the alignment should be zeroed before
5528 laying out the record. This means the alignment only serves to force fields
5529 to be bitfields, but not require the record to be that aligned. This is
5530 used for variants.
5532 ALL_REP, if true, means a rep clause was found for all the fields. This
5533 simplifies the logic since we know we're not in the mixed case.
5535 DEFER_DEBUG, if true, means that the debugging routines should not be
5536 called when finishing constructing the record type.
5538 UNCHECKED_UNION, if tree, means that we are building a type for a record
5539 with a Pragma Unchecked_Union.
5541 The processing of the component list fills in the chain with all of the
5542 fields of the record and then the record type is finished. */
5544 static void
5549 {
5550 Node_Id component_decl;
5551 Entity_Id gnat_field;
5552 Node_Id variant_part;
5558 /* For each variable within each component declaration create a GCC field
5559 and add it to the list, skipping any pragmas in the list. */
5565 {
5570 else
5571 {
5575 /* If this is the _Tag field, put it before any discriminants,
5576 instead of after them as is the case for all other fields.
5577 Ignore field of void type if only annotating. */
5580 else
5581 {
5584 }
5585 }
5588 }
5590 /* At the end of the component list there may be a variant part. */
5593 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
5594 mutually exclusive and should go in the same memory. To do this we need
5595 to treat each variant as a record whose elements are created from the
5596 component list for the variant. So here we create the records from the
5597 lists for the variants and put them all into the QUAL_UNION_TYPE.
5598 If this is an Unchecked_Union, we make a UNION_TYPE instead or
5599 use GNU_RECORD_TYPE if there are no fields so far. */
5601 {
5603 Node_Id variant;
5605 tree gnu_var_name
5609 tree gnu_union_type;
5610 tree gnu_union_name;
5611 tree gnu_union_field;
5622 else
5623 {
5625 gnu_union_type
5630 }
5635 {
5637 tree gnu_inner_name;
5638 tree gnu_qual;
5646 /* Set the alignment of the inner type in case we need to make
5647 inner objects into bitfields, but then clear it out
5648 so the record actually gets only the alignment required. */
5652 /* Similarly, if the outer record has a size specified and all fields
5653 have record rep clauses, we can propagate the size into the
5654 variant part. */
5656 {
5660 }
5672 /* If this is an Unchecked_Union and we have exactly one field,
5673 use that field here. */
5677 else
5678 {
5681 (all_rep_and_size
5684 (all_rep_and_size
5692 }
5696 }
5698 /* We used to delete the empty variants from the end. However,
5699 we no longer do that because we need them to generate complete
5700 debugging information for the variant record. Otherwise,
5701 the union type definition will be missing the fields associated
5702 to these empty variants. */
5704 /* Only make the QUAL_UNION_TYPE if there are any non-empty variants. */
5706 {
5708 {
5712 }
5717 /* If GNU_UNION_TYPE is our record type, it means we must have an
5718 Unchecked_Union with no fields. Verify that and, if so, just
5719 return. */
5721 {
5724 }
5726 gnu_union_field
5728 packed,
5735 }
5736 }
5738 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
5739 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do this
5740 in a separate pass since we want to handle the discriminants but can't
5741 play with them until we've used them in debugging data above.
5743 ??? Note: if we then reorder them, debugging information will be wrong,
5744 but there's nothing that can be done about this at the moment. */
5747 {
5749 {
5754 else
5760 }
5761 else
5762 {
5765 }
5766 }
5768 /* If we have any items in our rep'ed field list, it is not the case that all
5769 the fields in the record have rep clauses, and P_REP_LIST is nonzero,
5770 set it and ignore the items. */
5774 {
5775 /* Otherwise, sort the fields by bit position and put them into their
5776 own record if we have any fields without rep clauses. */
5777 tree gnu_rep_type
5789 /* Put the fields in the list in order of increasing position, which
5790 means we start from the end. */
5793 {
5797 }
5800 {
5806 }
5807 else
5808 {
5811 }
5812 }
5819 }
5820 \f
5821 /* Called via qsort from the above. Returns -1, 1, depending on the
5822 bit positions and ordinals of the two fields. Use DECL_UID to ensure
5823 a stable sort. */
5825 static int
5827 {
5835 else
5837 }
5838 \f
5839 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
5840 placed into an Esize, Component_Bit_Offset, or Component_Size value
5841 in the GNAT tree. */
5843 static Uint
5845 {
5847 TCode tcode;
5852 /* See if we've already saved the value for this node. */
5856 /* If we do not return inside this switch, TCODE will be set to the
5857 code to use for a Create_Node operand and LEN (set above) will be
5858 the number of recursive calls for us to make. */
5861 {
5866 /* This may have come from a conversion from some smaller type,
5867 so ensure this is in bitsizetype. */
5870 /* For negative values, use NEGATE_EXPR of the supplied value. */
5872 {
5873 /* The ridiculous code below is to handle the case of the largest
5874 negative integer. */
5877 tree temp;
5880 {
5881 negative_size
5884 bitsize_one_node));
5886 }
5893 }
5900 /* This peculiar test is to make sure that the size fits in an int
5901 on machines where HOST_WIDE_INT is not "int". */
5904 else
5908 /* The only case we handle here is a simple discriminant reference. */
5916 else
5922 /* Now just list the operations we handle. */
5954 }
5956 /* Now get each of the operands that's relevant for this code. If any
5957 cannot be expressed as a repinfo node, say we can't. */
5962 {
5966 }
5971 }
5973 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding
5974 GCC type, set Component_Bit_Offset and Esize to the position and size
5975 used by Gigi. */
5977 static void
5979 {
5980 tree gnu_list;
5981 tree gnu_entry;
5982 Entity_Id gnat_field;
5984 /* We operate by first making a list of all fields and their positions
5985 (we can get the sizes easily at any time) by a recursive call
5986 and then update all the sizes into the tree. */
5989 BIGGEST_ALIGNMENT);
5996 {
6000 gnu_list);
6003 {
6005 {
6006 /* In this mode the tag and parent components have not been
6007 generated, so we add the appropriate offset to each
6008 component. For a component appearing in the current
6009 extension, the offset is the size of the parent. */
6012 parent_offset
6014 bitsizetype);
6015 else
6017 }
6019 Set_Component_Bit_Offset
6021 annotate_value
6026 parent_offset)));
6030 }
6033 {
6034 /* If there is no gnu_entry, this is an inherited component whose
6035 position is the same as in the parent type. */
6036 Set_Component_Bit_Offset
6041 }
6042 }
6043 }
6045 /* Scan all fields in GNU_TYPE and build entries where TREE_PURPOSE is the
6046 FIELD_DECL and TREE_VALUE a TREE_LIST with TREE_PURPOSE being the byte
6047 position and TREE_VALUE being a TREE_LIST with TREE_PURPOSE the value to be
6048 placed into DECL_OFFSET_ALIGN and TREE_VALUE the bit position. GNU_POS is
6049 to be added to the position, GNU_BITPOS to the bit position, OFFSET_ALIGN is
6050 the present value of DECL_OFFSET_ALIGN and GNU_LIST is a list of the entries
6051 so far. */
6053 static tree
6056 {
6057 tree gnu_field;
6062 {
6067 unsigned int our_offset_align
6070 gnu_result
6075 NULL_TREE),
6076 gnu_result);
6079 gnu_result
6082 our_offset_align);
6083 }
6086 }
6087 \f
6088 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
6089 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
6090 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
6091 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
6092 for the size of a field. COMPONENT_P is true if we are being called
6093 to process the Component_Size of GNAT_OBJECT. This is used for error
6094 message handling and to indicate to use the object size of GNU_TYPE.
6095 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
6096 it means that a size of zero should be treated as an unspecified size. */
6098 static tree
6101 {
6102 Node_Id gnat_error_node;
6103 tree type_size
6105 tree size;
6107 /* Find the node to use for errors. */
6114 else
6117 /* Return 0 if no size was specified, either because Esize was not Present or
6118 the specified size was zero. */
6122 /* Get the size as a tree. Give an error if a size was specified, but cannot
6123 be represented as in sizetype. */
6126 {
6131 }
6133 /* Ignore a negative size since that corresponds to our back-annotation.
6134 Also ignore a zero size unless a size clause exists. */
6138 /* The size of objects is always a multiple of a byte. */
6141 {
6145 else
6149 }
6151 /* If this is an integral type or a packed array type, the front-end has
6152 verified the size, so we need not do it here (which would entail
6153 checking against the bounds). However, if this is an aliased object, it
6154 may not be smaller than the type of the object. */
6159 /* If the object is a record that contains a template, add the size of
6160 the template to the specified size. */
6165 /* Modify the size of the type to be that of the maximum size if it has a
6166 discriminant or the size of a thin pointer if this is a fat pointer. */
6172 /* If this is an access type, the minimum size is that given by the smallest
6173 integral mode that's valid for pointers. */
6175 {
6181 ;
6184 }
6186 /* If the size of the object is a constant, the new size must not be
6187 smaller. */
6191 {
6193 post_error_ne_tree
6196 else
6203 post_error_ne_tree_2
6213 }
6216 }
6217 \f
6218 /* Similarly, but both validate and process a value of RM_Size. This
6219 routine is only called for types. */
6221 static void
6223 {
6224 /* Only give an error if a Value_Size clause was explicitly given.
6225 Otherwise, we'd be duplicating an error on the Size clause. */
6226 Node_Id gnat_attr_node
6229 tree size;
6231 /* Get the size as a tree. Do nothing if none was specified, either
6232 because RM_Size was not Present or if the specified size was zero.
6233 Give an error if a size was specified, but cannot be represented as
6234 in sizetype. */
6240 {
6243 gnat_entity);
6246 }
6248 /* Ignore a negative size since that corresponds to our back-annotation.
6249 Also ignore a zero size unless a size clause exists, a Value_Size
6250 clause exists, or this is an integer type, in which case the
6251 front end will have always set it. */
6258 /* If the old size is self-referential, get the maximum size. */
6262 /* If the size of the object is a constant, the new size must not be
6263 smaller (the front end checks this for scalar types). */
6268 {
6270 post_error_ne_tree
6275 }
6277 /* Otherwise, set the RM_Size. */
6288 }
6289 \f
6290 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
6291 If TYPE is the best type, return it. Otherwise, make a new type. We
6292 only support new integral and pointer types. BIASED_P is nonzero if
6293 we are making a biased type. */
6295 static tree
6297 {
6298 tree new_type;
6302 /* If size indicates an error, just return TYPE to avoid propagating the
6303 error. Likewise if it's too large to represent. */
6309 {
6312 /* Only do something if the type is not already the proper size and is
6313 not a packed array type. */
6325 new_type
6337 /* Do something if this is a fat pointer, in which case we
6338 may need to return the thin pointer. */
6340 return
6341 build_pointer_type
6346 /* Only do something if this is a thin pointer, in which case we
6347 may need to return the fat pointer. */
6349 return
6356 }
6359 }
6360 \f
6361 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
6362 a type or object whose present alignment is ALIGN. If this alignment is
6363 valid, return it. Otherwise, give an error and return ALIGN. */
6365 static unsigned int
6367 {
6371 #ifndef MAX_OFILE_ALIGNMENT
6372 #define MAX_OFILE_ALIGNMENT BIGGEST_ALIGNMENT
6373 #endif
6378 /* Don't worry about checking alignment if alignment was not specified
6379 by the source program and we already posted an error for this entity. */
6384 /* Within GCC, an alignment is an integer, so we must make sure a
6385 value is specified that fits in that range. Also, alignments of
6386 more than MAX_OFILE_ALIGNMENT can't be supported. */
6400 else
6404 }
6405 \f
6406 /* Verify that OBJECT, a type or decl, is something we can implement
6407 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
6408 if we require atomic components. */
6410 static void
6412 {
6414 Node_Id gnat_node;
6417 tree size;
6419 /* There are three case of what OBJECT can be. It can be a type, in which
6420 case we take the size, alignment and mode from the type. It can be a
6421 declaration that was indirect, in which case the relevant values are
6422 that of the type being pointed to, or it can be a normal declaration,
6423 in which case the values are of the decl. The code below assumes that
6424 OBJECT is either a type or a decl. */
6426 {
6430 }
6432 {
6436 }
6437 else
6438 {
6442 }
6444 /* Consider all floating-point types atomic and any types that that are
6445 represented by integers no wider than a machine word. */
6452 /* For the moment, also allow anything that has an alignment equal
6453 to its size and which is smaller than a word. */
6461 {
6469 }
6474 else
6477 }
6478 \f
6479 /* Check if FTYPE1 and FTYPE2, two potentially different function type nodes,
6480 have compatible signatures so that a call using one type may be safely
6481 issued if the actual target function type is the other. Return 1 if it is
6482 the case, 0 otherwise, and post errors on the incompatibilities.
6484 This is used when an Ada subprogram is mapped onto a GCC builtin, to ensure
6485 that calls to the subprogram will have arguments suitable for the later
6486 underlying builtin expansion. */
6488 static int
6490 {
6491 /* As of now, we only perform very trivial tests and consider it's the
6492 programmer's responsibility to ensure the type correctness in the Ada
6493 declaration, as in the regular Import cases.
6495 Mismatches typically result in either error messages from the builtin
6496 expander, internal compiler errors, or in a real call sequence. This
6497 should be refined to issue diagnostics helping error detection and
6498 correction. */
6500 /* Almost fake test, ensuring a use of each argument. */
6505 }
6506 \f
6507 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new type
6508 with all size expressions that contain F updated by replacing F with R.
6509 This is identical to GCC's substitute_in_type except that it knows about
6510 TYPE_INDEX_TYPE. If F is NULL_TREE, always make a new RECORD_TYPE, even if
6511 nothing has changed. */
6513 tree
6515 {
6517 tree tem;
6520 {
6526 {
6535 SET_TYPE_INDEX_TYPE
6538 }
6545 {
6559 }
6573 /* Don't know how to do these yet. */
6577 {
6591 /* If we had bounded the sizes of T by a constant, bound the sizes of
6592 NEW by the same constant. */
6602 }
6607 {
6608 tree field;
6609 bool changed_field
6616 /* Start out with no fields, make new fields, and chain them
6617 in. If we haven't actually changed the type of any field,
6618 discard everything we've done and return the old type. */
6624 {
6635 /* If this is an internal field and the type of this field is
6636 a UNION_TYPE or RECORD_TYPE with no elements, ignore it. If
6637 the type just has one element, treat that as the field.
6638 But don't do this if we are processing a QUAL_UNION_TYPE. */
6643 {
6648 {
6649 tree next_new_field
6652 /* Make sure omitting the union doesn't change
6653 the layout. */
6656 }
6657 }
6664 /* If the size of the old field was set at a constant,
6665 propagate the size in case the type's size was variable.
6666 (This occurs in the case of a variant or discriminated
6667 record with a default size used as a field of another
6668 record.) */
6677 {
6683 /* Do the substitution inside the qualifier and if we find
6684 that this field will not be present, omit it. */
6689 }
6693 else
6698 /* If this is a qualified type and this field will always be
6699 present, we are done. */
6703 }
6705 /* If this used to be a qualified union type, but we now know what
6706 field will be present, make this a normal union. */
6717 /* If the size was originally a constant use it. */
6720 {
6724 }
6727 }
6731 }
6732 }
6733 \f
6734 /* Return the "RM size" of GNU_TYPE. This is the actual number of bits
6735 needed to represent the object. */
6737 tree
6739 {
6740 /* For integer types, this is the precision. For record types, we store
6741 the size explicitly. For other types, this is just the size. */
6747 /* Return the rm_size of the actual data plus the size of the template. */
6748 return
6758 else
6760 }
6761 \f
6762 /* Return an identifier representing the external name to be used for
6763 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
6764 and the specified suffix. */
6766 tree
6768 {
6777 /* A variable using the Stdcall convention (meaning we are running
6778 on a Windows box) live in a DLL. Here we adjust its name to use
6779 the jump-table, the _imp__NAME contains the address for the NAME
6780 variable. */
6783 {
6790 }
6793 }
6795 /* Return the name to be used for GNAT_ENTITY. If a type, create a
6796 fully-qualified name, possibly with type information encoding.
6797 Otherwise, return the name. */
6799 tree
6801 {
6804 }
6806 /* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
6807 string, return a new IDENTIFIER_NODE that is the concatenation of
6808 the name in GNU_ID and SUFFIX. */
6810 tree
6812 {
6821 }