| blob | b64463a53b619fcaa28b1887ea1549ad6ce7ae11 |
1 /****************************************************************************
2 * *
3 * GNAT COMPILER COMPONENTS *
4 * *
5 * D E C L *
6 * *
7 * C Implementation File *
8 * *
9 * Copyright (C) 1992-2005, Free Software Foundation, Inc. *
10 * *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 2, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License distributed with GNAT; see file COPYING. If not, write *
19 * to the Free Software Foundation, 51 Franklin Street, Fifth Floor, *
20 * Boston, MA 02110-1301, USA. *
21 * *
22 * GNAT was originally developed by the GNAT team at New York University. *
23 * Extensive contributions were provided by Ada Core Technologies Inc. *
24 * *
25 ****************************************************************************/
56 /* Convention_Stdcall should be processed in a specific way on Windows targets
57 only. The macro below is a helper to avoid having to check for a Windows
58 specific attribute throughout this unit. */
60 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
61 #define Has_Stdcall_Convention(E) (Convention (E) == Convention_Stdcall)
62 #else
63 #define Has_Stdcall_Convention(E) (0)
64 #endif
66 /* These two variables are used to defer recursively expanding incomplete
67 types while we are processing a record or subprogram type. */
70 static struct incomplete
71 {
73 tree old_type;
74 Entity_Id full_type;
77 /* These two variables are used to defer emission of debug information for
78 nested incomplete record types */
106 /* Given GNAT_ENTITY, an entity in the incoming GNAT tree, return a
107 GCC type corresponding to that entity. GNAT_ENTITY is assumed to
108 refer to an Ada type. */
110 tree
112 {
113 tree gnu_decl;
115 /* The back end never attempts to annotate generic types */
119 /* Convert the ada entity type into a GCC TYPE_DECL node. */
123 }
124 \f
125 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
126 entity, this routine returns the equivalent GCC tree for that entity
127 (an ..._DECL node) and associates the ..._DECL node with the input GNAT
128 defining identifier.
130 If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
131 initial value (in GCC tree form). This is optional for variables.
132 For renamed entities, GNU_EXPR gives the object being renamed.
134 DEFINITION is nonzero if this call is intended for a definition. This is
135 used for separate compilation where it necessary to know whether an
136 external declaration or a definition should be created if the GCC equivalent
137 was not created previously. The value of 1 is normally used for a non-zero
138 DEFINITION, but a value of 2 is used in special circumstances, defined in
139 the code. */
141 tree
143 {
144 tree gnu_entity_id;
146 /* Contains the gnu XXXX_DECL tree node which is equivalent to the input
147 GNAT tree. This node will be associated with the GNAT node by calling
148 the save_gnu_tree routine at the end of the `switch' statement. */
150 /* true if we have already saved gnu_decl as a gnat association. */
152 /* Nonzero if we incremented defer_incomplete_level. */
154 /* Nonzero if we incremented defer_debug_level. */
156 /* Nonzero if we incremented force_global. */
158 /* Nonzero if we should check to see if elaborated during processing. */
160 /* Nonzero if we made GNU_DECL and its type here. */
166 Entity_Id gnat_temp;
167 unsigned int esize
177 bool imported_p
182 /* Since a use of an Itype is a definition, process it as such if it
183 is not in a with'ed unit. */
188 {
189 /* Ensure that we are in a subprogram mentioned in the Scope
190 chain of this entity, our current scope is global,
191 or that we encountered a task or entry (where we can't currently
192 accurately check scoping). */
195 {
198 }
202 {
207 gnat_temp
219 && (current_function_decl
221 {
224 }
225 }
227 /* This abort means the entity "gnat_entity" has an incorrect scope,
228 i.e. that its scope does not correspond to the subprogram in which
229 it is declared */
231 }
233 /* If this is entity 0, something went badly wrong. */
236 /* If we've already processed this entity, return what we got last time.
237 If we are defining the node, we should not have already processed it.
238 In that case, we will abort below when we try to save a new GCC tree for
239 this object. We also need to handle the case of getting a dummy type
240 when a Full_View exists. */
243 && (! definition
245 {
252 {
258 }
261 }
263 /* If this is a numeric or enumeral type, or an access type, a nonzero
264 Esize must be specified unless it was specified by the programmer. */
272 /* Likewise, RM_Size must be specified for all discrete and fixed-point
273 types. */
277 /* Get the name of the entity and set up the line number and filename of
278 the original definition for use in any decl we make. */
282 /* If we get here, it means we have not yet done anything with this
283 entity. If we are not defining it here, it must be external,
284 otherwise we should have defined it already. */
291 /* For cases when we are not defining (i.e., we are referencing from
292 another compilation unit) Public entities, show we are at global level
293 for the purpose of computing scopes. Don't do this for components or
294 discriminants since the relevant test is whether or not the record is
295 being defined. But do this for Imported functions or procedures in
296 all cases. */
304 /* Handle any attributes directly attached to the entity. */
308 /* Machine_Attributes on types are expected to be propagated to subtypes.
309 The corresponding Gigi_Rep_Items are only attached to the first subtype
310 though, so we handle the propagation here. */
317 {
319 /* If this is a use of a deferred constant, get its full
320 declaration. */
322 {
327 }
329 /* If we have an external constant that we are not defining,
330 get the expression that is was defined to represent. We
331 may throw that expression away later if it is not a
332 constant.
333 Do not retrieve the expression if it is an aggregate, because
334 in complex instantiation contexts it may not be expanded */
343 /* Ignore deferred constant definitions; they are processed fully in the
344 front-end. For deferred constant references, get the full
345 definition. On the other hand, constants that are renamings are
346 handled like variable renamings. If No_Initialization is set, this is
347 not a deferred constant but a constant whose value is built
348 manually. */
353 {
357 }
360 {
365 }
370 /* We used to special case VMS exceptions here to directly map them to
371 their associated condition code. Since this code had to be masked
372 dynamically to strip off the severity bits, this caused trouble in
373 the GCC/ZCX case because the "type" pointers we store in the tables
374 have to be static. We now don't special case here anymore, and let
375 the regular processing take place, which leaves us with a regular
376 exception data object for VMS exceptions too. The condition code
377 mapping is taken care of by the front end and the bitmasking by the
378 runtime library. */
383 {
384 /* The GNAT record where the component was defined. */
387 /* If the variable is an inherited record component (in the case of
388 extended record types), just return the inherited entity, which
389 must be a FIELD_DECL. Likewise for discriminants.
390 For discriminants of untagged records which have explicit
391 stored discriminants, return the entity for the corresponding
392 stored discriminant. Also use Original_Record_Component
393 if the record has a private extension. */
397 {
398 gnu_decl
403 }
405 /* If the enclosing record has explicit stored discriminants,
406 then it is an untagged record. If the Corresponding_Discriminant
407 is not empty then this must be a renamed discriminant and its
408 Original_Record_Component must point to the corresponding explicit
409 stored discriminant (i.e., we should have taken the previous
410 branch). */
414 {
415 /* A tagged record has no explicit stored discriminants. */
419 gnu_decl
424 }
426 /* If the enclosing record has explicit stored discriminants,
427 then it is an untagged record. If the Corresponding_Discriminant
428 is not empty then this must be a renamed discriminant and its
429 Original_Record_Component must point to the corresponding explicit
430 stored discriminant (i.e., we should have taken the first
431 branch). */
438 /* Otherwise, if we are not defining this and we have no GCC type
439 for the containing record, make one for it. Then we should
440 have made our own equivalent. */
442 {
443 /* ??? If this is in a record whose scope is a protected
444 type and we have an Original_Record_Component, use it.
445 This is a workaround for major problems in protected type
446 handling. */
454 {
455 gnu_decl
461 }
467 }
469 else
470 /* Here we have no GCC type and this is a reference rather than a
471 definition. This should never happen. Most likely the cause is a
472 reference before declaration in the gnat tree for gnat_entity. */
474 }
480 /* Simple variables, loop variables, OUT parameters, and exceptions. */
481 object:
482 {
484 bool const_flag
499 {
503 else
505 }
507 /* Get the type after elaborating the renamed object. */
510 /* If this is a loop variable, its type should be the base type.
511 This is because the code for processing a loop determines whether
512 a normal loop end test can be done by comparing the bounds of the
513 loop against those of the base type, which is presumed to be the
514 size used for computation. But this is not correct when the size
515 of the subtype is smaller than the type. */
519 /* Reject non-renamed objects whose types are unconstrained arrays or
520 any object whose type is a dummy type or VOID_TYPE. */
526 {
529 force_global--;
531 }
533 /* If an alignment is specified, use it if valid. Note that
534 exceptions are objects but don't have alignments. We must do this
535 before we validate the size, since the alignment can affect the
536 size. */
538 {
544 }
546 /* If we are defining the object, see if it has a Size value and
547 validate it if so. If we are not defining the object and a Size
548 clause applies, simply retrieve the value. We don't want to ignore
549 the clause and it is expected to have been validated already. Then
550 get the new type, if any. */
559 {
560 gnu_type
566 }
568 /* If this object has self-referential size, it must be a record with
569 a default value. We are supposed to allocate an object of the
570 maximum size in this case unless it is a constant with an
571 initializing expression, in which case we can get the size from
572 that. Note that the resulting size may still be a variable, so
573 this may end up with an indirect allocation. */
577 {
579 gnu_size
580 = SUBSTITUTE_PLACEHOLDER_IN_EXPR
583 /* We may have no GNU_EXPR because No_Initialization is
584 set even though there's an Expression. */
589 gnu_size
591 (Etype
593 else
594 {
597 }
598 }
600 /* If the size is zero bytes, make it one byte since some linkers have
601 trouble with zero-sized objects. If the object will have a
602 template, that will make it nonzero so don't bother. Also avoid
603 doing that for an object renaming or an object with an address
604 clause, as we would lose useful information on the view size
605 (e.g. for null array slices) and we are not allocating the object
606 here anyway. */
615 /* If this is an atomic object with no specified size and alignment,
616 but where the size of the type is a constant, set the alignment to
617 the lowest power of two greater than the size, or to the
618 biggest meaningful alignment, whichever is smaller. */
622 {
625 BIGGEST_ALIGNMENT))
627 else
632 }
634 /* If the object is set to have atomic components, find the component
635 type and validate it.
637 ??? Note that we ignore Has_Volatile_Components on objects; it's
638 not at all clear what to do in that case. */
641 {
650 }
652 /* Now check if the type of the object allows atomic access. Note
653 that we must test the type, even if this object has size and
654 alignment to allow such access, because we will be going
655 inside the padded record to assign to the object. We could fix
656 this by always copying via an intermediate value, but it's not
657 clear it's worth the effort. */
661 /* If this is an aliased object with an unconstrained nominal subtype,
662 make a type that includes the template. */
666 {
667 tree gnu_fat
670 gnu_type
674 }
676 #ifdef MINIMUM_ATOMIC_ALIGNMENT
677 /* If the size is a constant and no alignment is specified, force
678 the alignment to be the minimum valid atomic alignment. The
679 restriction on constant size avoids problems with variable-size
680 temporaries; if the size is variable, there's no issue with
681 atomic access. Also don't do this for a constant, since it isn't
682 necessary and can interfere with constant replacement. Finally,
683 do not do it for Out parameters since that creates an
684 size inconsistency with In parameters. */
693 #endif
695 /* Make a new type with the desired size and alignment, if needed. */
699 /* Make a volatile version of this object's type if we are to
700 make the object volatile. Note that 13.3(19) says that we
701 should treat other types of objects as volatile as well. */
711 /* Convert the expression to the type of the object except in the
712 case where the object's type is unconstrained or the object's type
713 is a padded record whose field is of self-referential size. In
714 the former case, converting will generate unnecessary evaluations
715 of the CONSTRUCTOR to compute the size and in the latter case, we
716 want to only copy the actual data. */
722 && (CONTAINS_PLACEHOLDER_P
726 /* See if this is a renaming, and handle appropriately depending on
727 what is renamed and in which context. There are three major
728 cases:
730 1/ This is a constant renaming and we can just make an object
731 with what is renamed as its initial value,
733 2/ We can reuse a stabilized version of what is renamed in place
734 of the renaming,
736 3/ If neither 1 or 2 applies, we make the renaming entity a constant
737 pointer to what is being renamed. */
740 {
741 /* If the renamed object had padding, strip off the reference
742 to the inner object and reset our type. */
746 && (TYPE_IS_PADDING_P
748 {
751 }
753 /* Case 1: If this is a constant renaming, treat it as a normal
754 object whose initial value is what is being renamed. We cannot
755 do this if the type is unconstrained or class-wide. */
762 ;
764 /* Otherwise, see if we can proceed with a stabilized version of
765 the renamed entity or if we need to make a pointer. */
766 else
767 {
771 /* Case 2: If the renaming entity need not be materialized and
772 the renamed expression is something we can stabilize, use
773 that for the renaming. 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 /* If the type we are dealing with is to represent a packed array,
1420 we need to have the bits left justified on big-endian targets
1421 and right justified on little-endian targets. We also need to
1422 ensure that when the value is read (e.g. for comparison of two
1423 such values), we only get the good bits, since the unused bits
1424 are uninitialized. Both goals are accomplished by wrapping the
1425 modular value in an enclosing struct. */
1427 {
1429 tree gnu_field;
1438 /* Create a stripped-down declaration of the original type, mainly
1439 for debugging. */
1443 /* Don't notify the field as "addressable", since we won't be taking
1444 it's address and it would prevent create_field_decl from making a
1445 bitfield. */
1452 }
1457 /* If this is a VAX floating-point type, use an integer of the proper
1458 size. All the operations will be handled with ASM statements. */
1460 {
1465 sizetype));
1467 }
1469 /* The type of the Low and High bounds can be our type if this is
1470 a type from Standard, so set them at the end of the function. */
1478 {
1481 }
1483 {
1510 /* One of the above calls might have caused us to be elaborated,
1511 so don't blow up if so. */
1513 {
1516 }
1519 }
1522 /* Array and String Types and Subtypes
1524 Unconstrained array types are represented by E_Array_Type and
1525 constrained array types are represented by E_Array_Subtype. There
1526 are no actual objects of an unconstrained array type; all we have
1527 are pointers to that type.
1529 The following fields are defined on array types and subtypes:
1531 Component_Type Component type of the array.
1532 Number_Dimensions Number of dimensions (an int).
1533 First_Index Type of first index. */
1537 {
1543 int firstdim
1545 int nextdim
1551 tree gnu_max_size_unit;
1553 Entity_Id gnat_ind_subtype;
1554 Entity_Id gnat_ind_base_subtype;
1555 tree gnu_template_reference;
1556 tree tem;
1564 /* Make a node for the array. If we are not defining the array
1565 suppress expanding incomplete types. */
1571 /* Build the fat pointer type. Use a "void *" object instead of
1572 a pointer to the array type since we don't have the array type
1573 yet (it will reference the fat pointer via the bounds). */
1576 ptr_void_type_node,
1579 gnu_ptr_template,
1582 /* Make sure we can put this into a register. */
1586 /* Build a reference to the template from a PLACEHOLDER_EXPR that
1587 is the fat pointer. This will be used to access the individual
1588 fields once we build them. */
1592 gnu_template_reference
1596 /* Now create the GCC type for each index and add the fields for
1597 that index to the template. */
1599 gnat_ind_base_subtype
1605 {
1607 tree gnu_ind_subtype
1609 tree gnu_base_subtype
1611 tree gnu_base_min
1613 tree gnu_base_max
1617 /* Make the FIELD_DECLs for the minimum and maximum of this
1618 type and then make extractions of that field from the
1619 template. */
1622 gnu_ind_subtype,
1626 gnu_ind_subtype,
1635 /* We can't use build_component_ref here since the template
1636 type isn't complete yet. */
1639 NULL_TREE);
1642 NULL_TREE);
1645 /* Make a range type with the new ranges, but using
1646 the Ada subtype. Then we convert to sizetype. */
1652 /* Update the maximum size of the array, in elements. */
1653 gnu_max_size
1657 gnu_base_min)));
1661 }
1664 gnu_template_fields
1667 /* Install all the fields into the template. */
1672 /* Now make the array of arrays and update the pointer to the array
1673 in the fat pointer. Note that it is the first field. */
1677 /* Get and validate any specified Component_Size, but if Packed,
1678 ignore it since the front end will have taken care of it. */
1679 gnu_comp_size
1681 gnat_entity,
1689 /* If the component type is a RECORD_TYPE that has a self-referential
1690 size, use the maxium size. */
1696 {
1700 }
1706 /* If Component_Size is not already specified, annotate it with the
1707 size of the component. */
1717 gnu_max_size),
1721 {
1725 /* If the type below this an multi-array type, then this
1726 does not not have aliased components.
1728 ??? Otherwise, for now, we say that any component of aggregate
1729 type is addressable because the front end may take 'Reference
1730 of it. But we have to make it addressable if it must be passed
1731 by reference or it that is the default. */
1737 }
1739 /* If an alignment is specified, use it if valid. But ignore it for
1740 types that represent the unpacked base type for packed arrays. */
1743 {
1748 }
1754 /* The result type is an UNCONSTRAINED_ARRAY_TYPE that indicates the
1755 corresponding fat pointer. */
1762 /* If the maximum size doesn't overflow, use it. */
1777 /* Create a record type for the object and its template and
1778 set the template at a negative offset. */
1790 /* Give the thin pointer type a name. */
1794 gnat_entity);
1795 }
1801 /* This is the actual data type for array variables. Multidimensional
1802 arrays are implemented in the gnu tree as arrays of arrays. Note
1803 that for the moment arrays which have sparse enumeration subtypes as
1804 index components create sparse arrays, which is obviously space
1805 inefficient but so much easier to code for now.
1807 Also note that the subtype never refers to the unconstrained
1808 array type, which is somewhat at variance with Ada semantics.
1810 First check to see if this is simply a renaming of the array
1811 type. If so, the result is the array type. */
1816 else
1817 {
1820 int first_dim
1823 int next_dim
1825 Entity_Id gnat_ind_subtype;
1826 Entity_Id gnat_ind_base_subtype;
1831 tree gnu_max_size_unit;
1835 /* First create the gnu types for each index. Create types for
1836 debugging information to point to the index types if the
1837 are not integer types, have variable bounds, or are
1838 wider than sizetype. */
1841 gnat_ind_base_subtype
1847 {
1848 tree gnu_index_subtype
1850 tree gnu_min
1852 tree gnu_max
1854 tree gnu_base_subtype
1856 tree gnu_base_min
1858 tree gnu_base_max
1861 tree gnu_base_base_min
1863 tree gnu_base_base_max
1865 tree gnu_high;
1866 tree gnu_this_max;
1868 /* If the minimum and maximum values both overflow in
1869 SIZETYPE, but the difference in the original type
1870 does not overflow in SIZETYPE, ignore the overflow
1871 indications. */
1879 && (!TREE_OVERFLOW
1887 /* Similarly, if the range is null, use bounds of 1..0 for
1888 the sizetype bounds. */
1900 /* Now compute the size of this bound. We need to provide
1901 GCC with an upper bound to use but have to deal with the
1902 "superflat" case. There are three ways to do this. If we
1903 can prove that the array can never be superflat, we can
1904 just use the high bound of the index subtype. If we can
1905 prove that the low bound minus one can't overflow, we
1906 can do this as MAX (hb, lb - 1). Otherwise, we have to use
1907 the expression hb >= lb ? hb : lb - 1. */
1910 /* See if the base array type is already flat. If it is, we
1911 are probably compiling an ACVC test, but it will cause the
1912 code below to malfunction if we don't handle it specially. */
1920 /* If gnu_high is now an integer which overflowed, the array
1921 cannot be superflat. */
1928 else
1929 gnu_high
1930 = build_cond_expr
1938 /* Also compute the maximum size of the array. Here we
1939 see if any constraint on the index type of the base type
1940 can be used in the case of self-referential bound on
1941 the index type of the subtype. We look for a non-"infinite"
1942 and non-self-referential bound from any type involved and
1943 handle each bound separately. */
1968 gnu_this_max
1972 gnu_base_min)),
1973 size_zero_node);
1979 gnu_max_size
1993 }
1995 /* Then flatten: create the array of arrays. */
1999 /* One of the above calls might have caused us to be elaborated,
2000 so don't blow up if so. */
2002 {
2005 }
2007 /* Get and validate any specified Component_Size, but if Packed,
2008 ignore it since the front end will have taken care of it. */
2009 gnu_comp_size
2011 gnat_entity,
2016 /* If the component type is a RECORD_TYPE that has a self-referential
2017 size, use the maxium size. */
2023 {
2028 }
2042 {
2045 /* If the type below this an multi-array type, then this
2046 does not not have aliased components.
2048 ??? Otherwise, for now, we say that any component of aggregate
2049 type is addressable because the front end may take 'Reference
2050 of it. But we have to make it addressable if it must be passed
2051 by reference or it that is the default. */
2057 }
2059 /* If we are at file level and this is a multi-dimensional array, we
2060 need to make a variable corresponding to the stride of the
2061 inner dimensions. */
2063 {
2065 tree gnu_arr_type;
2071 {
2079 /* ??? For now, store the size as a multiple of the
2080 alignment of the element type in bytes so that we
2081 can see the alignment from the tree. */
2083 = build_binary_op
2085 elaborate_expression_1
2094 }
2095 }
2097 /* If we need to write out a record type giving the names of
2098 the bounds, do it now. */
2100 {
2103 tree gnu_field;
2109 {
2110 tree gnu_type_name
2117 integer_type_node,
2118 gnu_bound_rec_type,
2122 }
2126 }
2133 /* If our size depends on a placeholder and the maximum size doesn't
2134 overflow, use it. */
2141 {
2147 }
2149 /* Set our alias set to that of our base type. This gives all
2150 array subtypes the same alias set. */
2152 }
2154 /* If this is a packed type, make this type the same as the packed
2155 array type, but do some adjusting in the type first. */
2158 {
2159 Entity_Id gnat_index;
2160 tree gnu_inner_type;
2162 /* First finish the type we had been making so that we output
2163 debugging information for it */
2164 gnu_type
2167 | (TYPE_QUAL_VOLATILE
2175 /* Save it as our equivalent in case the call below elaborates
2176 this type again. */
2190 /* We need to point the type we just made to our index type so
2191 the actual bounds can be put into a template. */
2197 {
2199 {
2200 /* The TYPE_ACTUAL_BOUNDS field is also used for the modulus.
2201 If it is, we need to make another type. */
2203 {
2204 tree gnu_subtype;
2221 }
2224 }
2230 SET_TYPE_ACTUAL_BOUNDS
2237 SET_TYPE_ACTUAL_BOUNDS
2244 }
2245 }
2247 /* Abort if packed array with no packed array type field set. */
2248 else
2254 /* Create the type for a string literal. */
2255 {
2256 Entity_Id gnat_full_type
2261 tree gnu_string_array_type
2263 tree gnu_string_index_type
2266 tree gnu_lower_bound
2271 tree gnu_upper_bound
2273 gnu_lower_bound,
2275 tree gnu_range_type
2278 tree gnu_index_type
2283 gnu_range_type);
2285 gnu_type
2287 gnu_index_type);
2289 }
2292 /* Record Types and Subtypes
2294 The following fields are defined on record types:
2296 Has_Discriminants True if the record has discriminants
2297 First_Discriminant Points to head of list of discriminants
2298 First_Entity Points to head of list of fields
2299 Is_Tagged_Type True if the record is tagged
2301 Implementation of Ada records and discriminated records:
2303 A record type definition is transformed into the equivalent of a C
2304 struct definition. The fields that are the discriminants which are
2305 found in the Full_Type_Declaration node and the elements of the
2306 Component_List found in the Record_Type_Definition node. The
2307 Component_List can be a recursive structure since each Variant of
2308 the Variant_Part of the Component_List has a Component_List.
2310 Processing of a record type definition comprises starting the list of
2311 field declarations here from the discriminants and the calling the
2312 function components_to_record to add the rest of the fields from the
2313 component list and return the gnu type node. The function
2314 components_to_record will call itself recursively as it traverses
2315 the tree. */
2319 {
2320 gnu_type
2321 = build_complex_type
2322 (get_unpadded_type
2325 (Component_List
2326 (Type_Definition
2330 }
2332 {
2335 Entity_Id gnat_field;
2336 tree gnu_field;
2338 tree gnu_get_parent;
2345 bool is_extension
2349 /* See if all fields have a rep clause. Stop when we find one
2350 that doesn't. */
2359 /* If this is a record extension, go a level further to find the
2360 record definition. Also, verify we have a Parent_Subtype. */
2362 {
2369 }
2371 /* Make a node for the record. If we are not defining the record,
2372 suppress expanding incomplete types. We use the same RECORD_TYPE
2373 as for a dummy type and reset TYPE_DUMMY_P to show it's no longer
2374 a dummy.
2376 It is very tempting to delay resetting this bit until we are done
2377 with completing the type, e.g. to let possible intermediate
2378 elaboration of access types designating the record know it is not
2379 complete and arrange for update_pointer_to to fix things up later.
2381 It would be wrong, however, because dummy types are expected only
2382 to be created for Ada incomplete or private types, which is not
2383 what we have here. Doing so would make other parts of gigi think
2384 we are dealing with a really incomplete or private type, and have
2385 nasty side effects, typically on the generation of the associated
2386 debugging information. */
2399 /* If both a size and rep clause was specified, put the size in
2400 the record type now so that it can get the proper mode. */
2404 /* Always set the alignment here so that it can be used to
2405 set the mode, if it is making the alignment stricter. If
2406 it is invalid, it will be checked again below. If this is to
2407 be Atomic, choose a default alignment of a word unless we know
2408 the size and it's smaller. */
2417 /* If we have a Parent_Subtype, make a field for the parent. If
2418 this record has rep clauses, force the position to zero. */
2420 {
2421 tree gnu_parent;
2423 /* A major complexity here is that the parent subtype will
2424 reference our discriminants. But those must reference
2425 the parent component of this record. So here we will
2426 initialize each of those components to a COMPONENT_REF.
2427 The first operand of that COMPONENT_REF is another
2428 COMPONENT_REF which will be filled in below, once
2429 the parent type can be safely built. */
2434 NULL_TREE),
2435 NULL_TREE);
2442 save_gnu_tree
2446 gnu_get_parent,
2449 NULL_TREE),
2454 gnu_field_list
2464 }
2466 /* Add the fields for the discriminants into the record. */
2472 {
2473 /* If this is a record extension and this discriminant
2474 is the renaming of another discriminant, we've already
2475 handled the discriminant above. */
2480 gnu_field
2483 /* Make an expression using a PLACEHOLDER_EXPR from the
2484 FIELD_DECL node just created and link that with the
2485 corresponding GNAT defining identifier. Then add to the
2486 list of fields. */
2496 }
2498 /* Put the discriminants into the record (backwards), so we can
2499 know the appropriate discriminant to use for the names of the
2500 variants. */
2503 /* Add the listed fields into the record and finish up. */
2509 {
2511 defer_debug_level++;
2513 defer_debug_incomplete_list
2515 defer_debug_incomplete_list);
2516 }
2518 /* We used to remove the associations of the discriminants and
2519 _Parent for validity checking, but we may need them if there's
2520 Freeze_Node for a subtype used in this record. */
2525 /* If it is a tagged record force the type to BLKmode to insure
2526 that these objects will always be placed in memory. Do the
2527 same thing for limited record types. */
2531 /* If this is a derived type, we must make the alias set of this type
2532 the same as that of the type we are derived from. We assume here
2533 that the other type is already frozen. */
2539 /* Fill in locations of fields. */
2542 /* If there are any entities in the chain corresponding to
2543 components that we did not elaborate, ensure we elaborate their
2544 types if they are Itypes. */
2552 }
2556 /* If an equivalent type is present, that is what we should use.
2557 Otherwise, fall through to handle this like a record subtype
2558 since it may have constraints. */
2561 {
2566 }
2568 /* ... fall through ... */
2572 /* If Cloned_Subtype is Present it means this record subtype has
2573 identical layout to that type or subtype and we should use
2574 that GCC type for this one. The front end guarantees that
2575 the component list is shared. */
2577 {
2581 }
2583 /* Otherwise, first ensure the base type is elaborated. Then, if we are
2584 changing the type, make a new type with each field having the
2585 type of the field in the new subtype but having the position
2586 computed by transforming every discriminant reference according
2587 to the constraints. We don't see any difference between
2588 private and nonprivate type here since derivations from types should
2589 have been deferred until the completion of the private type. */
2590 else
2591 {
2593 tree gnu_base_type;
2594 tree gnu_orig_type;
2599 /* Get the base type initially for its alignment and sizes. But
2600 if it is a padded type, we do all the other work with the
2601 unpadded type. */
2610 {
2613 }
2615 /* When the type has discriminants, and these discriminants
2616 affect the shape of what it built, factor them in.
2618 If we are making a subtype of an Unchecked_Union (must be an
2619 Itype), just return the type.
2621 We can't just use Is_Constrained because private subtypes without
2622 discriminants of full types with discriminants with default
2623 expressions are Is_Constrained but aren't constrained! */
2631 {
2632 Entity_Id gnat_field;
2634 tree gnu_pos_list
2637 BIGGEST_ALIGNMENT);
2638 tree gnu_subst_list
2640 definition);
2641 tree gnu_temp;
2647 gnat_entity);
2659 {
2660 tree gnu_old_field
2663 tree gnu_offset
2665 gnu_pos_list));
2668 tree gnu_field_type
2672 unsigned int offset_align
2675 tree gnu_field;
2677 /* If there was a component clause, the field types must be
2678 the same for the type and subtype, so copy the data from
2679 the old field to avoid recomputation here. Also if the
2680 field is justified modular and the optimization in
2681 gnat_to_gnu_field was applied. */
2688 {
2691 }
2693 /* If this was a bitfield, get the size from the old field.
2694 Also ensure the type can be placed into a bitfield. */
2696 {
2702 }
2711 /* If the size is now a constant, we can set it as the
2712 size of the field when we make it. Otherwise, we need
2713 to deal with it specially. */
2717 gnu_field
2718 = create_field_decl
2724 {
2733 bitsize_unit_node));
2735 }
2739 SET_DECL_ORIGINAL_FIELD
2750 }
2752 /* Now go through the entities again looking for Itypes that
2753 we have not elaborated but should (e.g., Etypes of fields
2754 that have Original_Components). */
2765 /* Now set the size, alignment and alias set of the new type to
2766 match that of the old one, doing any substitutions, as
2767 above. */
2793 SET_TYPE_ADA_SIZE
2798 /* Recompute the mode of this record type now that we know its
2799 actual size. */
2802 /* Fill in locations of fields. */
2804 }
2806 /* If we've made a new type, record it and make an XVS type to show
2807 what this is a subtype of. Some debuggers require the XVS
2808 type to be output first, so do it in that order. */
2810 {
2812 {
2823 integer_type_node,
2824 gnu_subtype_marker,
2828 }
2835 }
2837 /* Otherwise, go down all the components in the new type and
2838 make them equivalent to those in the base type. */
2839 else
2846 gnat_to_gnu_field_decl
2848 }
2853 /* If we are not defining this entity, and we have incomplete
2854 entities being processed above us, make a dummy type and
2855 fill it in later. */
2857 {
2861 gnu_type
2862 = build_pointer_type
2875 }
2877 /* ... fall through ... */
2884 {
2886 Entity_Id gnat_desig_full
2888 Incomplete_Or_Private_Kind))
2890 /* We want to know if we'll be seeing the freeze node for any
2891 incomplete type we may be pointing to. */
2892 bool in_main_unit
2908 {
2910 {
2914 }
2916 Incomplete_Or_Private_Kind))
2918 }
2923 /* If either the designated type or its full view is an
2924 unconstrained array subtype, replace it with the type it's a
2925 subtype of. This avoids problems with multiple copies of
2926 unconstrained array types. */
2935 /* If the designated type is a subtype of an incomplete record type,
2936 use the parent type to avoid order of elaboration issues. This
2937 can lose some code efficiency, but there is no alternative. */
2943 /* If we are pointing to an incomplete type whose completion is an
2944 unconstrained array, make a fat pointer type instead of a pointer
2945 to VOID. The two types in our fields will be pointers to VOID and
2946 will be replaced in update_pointer_to. Similarly, if the type
2947 itself is a dummy type or an unconstrained array. Also make
2948 a dummy TYPE_OBJECT_RECORD_TYPE in case we have any thin
2949 pointers to it. */
2965 && defer_incomplete_level
2969 {
2970 tree gnu_old
2974 tree fields;
2976 /* Show the dummy we get will be a fat pointer. */
2979 /* If the call above got something that has a pointer, that
2980 pointer is our type. This could have happened either
2981 because the type was elaborated or because somebody
2982 else executed the code below. */
2985 {
2991 fields
2993 create_field_decl
2998 ptr_void_type_node,
3001 /* Make sure we can place this into a register. */
3012 }
3013 }
3015 /* If we already know what the full type is, use it. */
3020 /* Get the type of the thing we are to point to and build a pointer
3021 to it. If it is a reference to an incomplete or private type with a
3022 full view that is a record, make a dummy type node and get the
3023 actual type later when we have verified it is safe. */
3029 {
3032 }
3034 /* Likewise if we are pointing to a record or array and we are to defer
3035 elaborating incomplete types. We do this since this access type
3036 may be the full view of some private type. Note that the
3037 unconstrained array case is handled above. */
3045 {
3048 }
3050 {
3051 gnu_type
3053 p_mode,
3056 }
3057 else
3060 /* It is possible that the above call to gnat_to_gnu_type resolved our
3061 type. If so, just return it. */
3063 {
3066 }
3068 /* If we have a GCC type for the designated type, possibly modify it
3069 if we are pointing only to constant objects and then make a pointer
3070 to it. Don't do this for unconstrained arrays. */
3072 {
3075 {
3076 gnu_desig_type
3077 = build_qualified_type
3081 /* Some extra processing is required if we are building a
3082 pointer to an incomplete type (in the GCC sense). We might
3083 have such a type if we just made a dummy, or directly out
3084 of the call to gnat_to_gnu_type above if we are processing
3085 an access type for a record component designating the
3086 record type itself. */
3088 {
3089 /* We must ensure that the pointer to variant we make will
3090 be processed by update_pointer_to when the initial type
3091 is completed. Pretend we made a dummy and let further
3092 processing act as usual. */
3095 /* We must ensure that update_pointer_to will not retrieve
3096 the dummy variant when building a properly qualified
3097 version of the complete type. We take advantage of the
3098 fact that get_qualified_type is requiring TYPE_NAMEs to
3099 match to influence build_qualified_type and then also
3100 update_pointer_to here. */
3103 }
3104 }
3106 gnu_type
3109 }
3111 /* If we are not defining this object and we made a dummy pointer,
3112 save our current definition, evaluate the actual type, and replace
3113 the tentative type we made with the actual one. If we are to defer
3114 actually looking up the actual type, make an entry in the
3115 deferred list. */
3118 {
3119 tree gnu_old_type
3125 gnu_type
3126 = build_pointer_type
3127 (TYPE_OBJECT_RECORD_TYPE
3137 /* Note that the call to gnat_to_gnu_type here might have
3138 updated gnu_old_type directly, in which case it is not a
3139 dummy type any more when we get into update_pointer_to.
3141 This may happen for instance when the designated type is a
3142 record type, because their elaboration starts with an
3143 initial node from make_dummy_type, which may yield the same
3144 node as the one we got.
3146 Besides, variants of this non-dummy type might have been
3147 created along the way. update_pointer_to is expected to
3148 properly take care of those situations. */
3151 else
3152 {
3160 }
3161 }
3162 }
3169 else
3170 /* The runtime representation is the equivalent type. */
3184 /* We treat this as identical to its base type; any constraint is
3185 meaningful only to the front end.
3187 The designated type must be elaborated as well, if it does
3188 not have its own freeze node. Designated (sub)types created
3189 for constrained components of records with discriminants are
3190 not frozen by the front end and thus not elaborated by gigi,
3191 because their use may appear before the base type is frozen,
3192 and because it is not clear that they are needed anywhere in
3193 Gigi. With the current model, there is no correct place where
3194 they could be elaborated. */
3201 {
3202 /* If we are not defining this entity, and we have incomplete
3203 entities being processed above us, make a dummy type and
3204 elaborate it later. */
3206 {
3209 tree gnu_ptr_type
3210 = build_pointer_type
3217 }
3220 Incomplete_Or_Private_Kind))
3221 ;
3222 else
3225 }
3230 /* Subprogram Entities
3232 The following access functions are defined for subprograms (functions
3233 or procedures):
3235 First_Formal The first formal parameter.
3236 Is_Imported Indicates that the subprogram has appeared in
3237 an INTERFACE or IMPORT pragma. For now we
3238 assume that the external language is C.
3239 Is_Inlined True if the subprogram is to be inlined.
3241 In addition for function subprograms we have:
3243 Etype Return type of the function.
3245 Each parameter is first checked by calling must_pass_by_ref on its
3246 type to determine if it is passed by reference. For parameters which
3247 are copied in, if they are Ada IN OUT or OUT parameters, their return
3248 value becomes part of a record which becomes the return type of the
3249 function (C function - note that this applies only to Ada procedures
3250 so there is no Ada return type). Additional code to store back the
3251 parameters will be generated on the caller side. This transformation
3252 is done here, not in the front-end.
3254 The intended result of the transformation can be seen from the
3255 equivalent source rewritings that follow:
3257 struct temp {int a,b};
3258 procedure P (A,B: IN OUT ...) is temp P (int A,B) {
3259 .. ..
3260 end P; return {A,B};
3261 }
3262 procedure call
3264 {
3265 temp t;
3266 P(X,Y); t = P(X,Y);
3267 X = t.a , Y = t.b;
3268 }
3270 For subprogram types we need to perform mainly the same conversions to
3271 GCC form that are needed for procedures and function declarations. The
3272 only difference is that at the end, we make a type declaration instead
3273 of a function declaration. */
3278 {
3279 /* The first GCC parameter declaration (a PARM_DECL node). The
3280 PARM_DECL nodes are chained through the TREE_CHAIN field, so this
3281 actually is the head of this parameter list. */
3283 /* The type returned by a function. If the subprogram is a procedure
3284 this type should be void_type_node. */
3286 /* List of fields in return type of procedure with copy in copy out
3287 parameters. */
3289 /* Non-null for subprograms containing parameters passed by copy in
3290 copy out (Ada IN OUT or OUT parameters not passed by reference),
3291 in which case it is the list of nodes used to specify the values of
3292 the in out/out parameters that are returned as a record upon
3293 procedure return. The TREE_PURPOSE of an element of this list is
3294 a field of the record and the TREE_VALUE is the PARM_DECL
3295 corresponding to that field. This list will be saved in the
3296 TYPE_CI_CO_LIST field of the FUNCTION_TYPE node we create. */
3298 /* If an import pragma asks to map this subprogram to a GCC builtin,
3299 this is the builtin DECL node. */
3301 Entity_Id gnat_param;
3304 bool extern_flag
3316 /* A parameter may refer to this type, so defer completion
3317 of any incomplete types. */
3320 /* If the subprogram has an alias, it is probably inherited, so
3321 we can use the original one. If the original "subprogram"
3322 is actually an enumeration literal, it may be the first use
3323 of its type, so we must elaborate that type now. */
3325 {
3332 /* Elaborate any Itypes in the parameters of this entity. */
3340 }
3342 /* If this subprogram is expectedly bound to a GCC builtin, fetch the
3343 corresponding DECL node.
3345 We still want the parameter associations to take place because the
3346 proper generation of calls depends on it (a GNAT parameter without
3347 a corresponding GCC tree has a very specific meaning), so we don't
3348 just break here. */
3352 /* ??? What if we don't find the builtin node above ? warn ? err ?
3353 In the current state we neither warn nor err, and calls will just
3354 be handled as for regular subprograms. */
3359 /* If this function returns by reference, make the actual
3360 return type of this function the pointer and mark the decl. */
3362 {
3365 }
3367 /* If the Mechanism is By_Reference, ensure the return type uses
3368 the machine's by-reference mechanism, which may not the same
3369 as above (e.g., it might be by passing a fake parameter). */
3372 {
3375 }
3377 /* If we are supposed to return an unconstrained array,
3378 actually return a fat pointer and make a note of that. Return
3379 a pointer to an unconstrained record of variable size. */
3381 {
3384 }
3386 /* If the type requires a transient scope, the result is allocated
3387 on the secondary stack, so the result type of the function is
3388 just a pointer. */
3390 {
3393 }
3395 /* If the type is a padded type and the underlying type would not
3396 be passed by reference or this function has a foreign convention,
3397 return the underlying type. */
3405 /* If the return type is unconstrained, that means it must have a
3406 maximum size. We convert the function into a procedure and its
3407 caller will pass a pointer to an object of that maximum size as the
3408 first parameter when we call the function. */
3410 {
3412 gnu_param_list
3417 }
3419 /* If the return type has a size that overflows, we cannot have
3420 a function that returns that type. This usage doesn't make
3421 sense anyway, so give an error here. */
3424 {
3426 gnat_entity);
3432 }
3434 /* Look at all our parameters and get the type of
3435 each. While doing this, build a copy-out structure if
3436 we need one. */
3441 {
3451 /* Builtins are expanded inline and there is no real call sequence
3452 involved. so the type expected by the underlying expander is
3453 always the type of each argument "as is". */
3457 /* Otherwise, see if a Mechanism was supplied that forced this
3458 parameter to be passed one way or another. */
3462 ;
3470 {
3476 else
3478 }
3479 else
3482 /* If this is either a foreign function or if the
3483 underlying type won't be passed by reference, strip off
3484 possible padding type. */
3490 && (req_by_copy
3492 (TYPE_FIELDS
3496 /* If this is an IN parameter it is read-only, so make a variant
3497 of the type that is read-only.
3499 ??? However, if this is an unconstrained array, that type can
3500 be very complex. So skip it for now. Likewise for any other
3501 self-referential type. */
3505 gnu_param_type
3510 /* For foreign conventions, pass arrays as a pointer to the
3511 underlying type. First check for unconstrained array and get
3512 the underlying array. Then get the component type and build
3513 a pointer to it. */
3516 gnu_param_type
3521 gnu_param_type
3522 = build_pointer_type
3527 && !req_by_copy
3529 {
3530 /* Strip off any multi-dimensional entries, then strip
3531 off the last array to get the component type. */
3540 gnu_param_type
3546 }
3548 /* Fat pointers are passed as thin pointers for foreign
3549 conventions. */
3552 gnu_param_type
3556 /* If we must pass or were requested to pass by reference, do so.
3557 If we were requested to pass by copy, do so.
3558 Otherwise, for foreign conventions, pass all in out parameters
3559 or aggregates by reference. For COBOL and Fortran, pass
3560 all integer and FP types that way too. For Convention Ada,
3561 use the standard Ada default. */
3563 || (!req_by_copy
3573 /* For convention Ada, see if we pass by reference
3574 by default. */
3577 {
3580 }
3588 /* If this is an OUT parameter that isn't passed by reference
3589 and isn't a pointer or aggregate, we don't make a PARM_DECL
3590 for it. Instead, it will be a VAR_DECL created when we process
3591 the procedure. For the special parameter of Valued_Procedure,
3592 never pass it in.
3594 An exception is made to cover the RM-6.4.1 rule requiring "by
3595 copy" out parameters with discriminants or implicit initial
3596 values to be handled like in out parameters. These type are
3597 normally built as aggregates, and hence passed by reference,
3598 except for some packed arrays which end up encoded in special
3599 integer types.
3601 The exception we need to make is then for packed arrays of
3602 records with discriminants or implicit initial values. We have
3603 no light/easy way to check for the latter case, so we merely
3604 check for packed arrays of records. This may lead to useless
3605 copy-in operations, but in very rare cases only, as these would
3606 be exceptions in a set of already exceptional situations. */
3609 || (!by_descr_p
3617 else
3618 {
3619 gnu_param
3620 = create_param_decl
3622 by_ref_p || by_component_ptr_p
3636 /* If a parameter is a pointer, this function may modify
3637 memory through it and thus shouldn't be considered
3638 a pure function. Also, the memory may be modified
3639 between two calls, so they can't be CSE'ed. The latter
3640 case also handles by-ref parameters. */
3644 }
3647 {
3649 {
3654 }
3663 gnu_return_list);
3664 }
3665 }
3667 /* Do not compute record for out parameters if subprogram is
3668 stubbed since structures are incomplete for the back-end. */
3671 {
3672 /* If all types are not complete, defer emission of debug
3673 information for this record types. Otherwise, we risk emitting
3674 debug information for a dummy type contained in the fields
3675 for that record. */
3680 {
3682 defer_debug_level++;
3684 defer_debug_incomplete_list
3686 defer_debug_incomplete_list);
3687 }
3688 }
3690 /* If we have a CICO list but it has only one entry, we convert
3691 this function into a function that simply returns that one
3692 object. */
3697 {
3707 }
3709 /* Both lists ware built in reverse. */
3713 gnu_type
3716 returns_by_ref,
3718 returns_by_target_ptr);
3720 /* A subprogram (something that doesn't return anything) shouldn't
3721 be considered Pure since there would be no reason for such a
3722 subprogram. Note that procedures with Out (or In Out) parameters
3723 have already been converted into a function with a return type. */
3727 gnu_type
3735 /* If we have a builtin decl for that function, check the signatures
3736 compatibilities. If the signatures are compatible, use the builtin
3737 decl. If they are not, we expect the checker predicate to have
3738 posted the appropriate errors, and just continue with what we have
3739 so far. */
3741 {
3745 {
3749 }
3750 }
3752 /* If there was no specified Interface_Name and the external and
3753 internal names of the subprogram are the same, only use the
3754 internal name to allow disambiguation of nested subprograms. */
3758 /* If we are defining the subprogram and it has an Address clause
3759 we must get the address expression from the saved GCC tree for the
3760 subprogram if it has a Freeze_Node. Otherwise, we elaborate
3761 the address expression here since the front-end has guaranteed
3762 in that case that the elaboration has no effects. If there is
3763 an Address clause and we are not defining the object, just
3764 make it a constant. */
3766 {
3770 gnu_address
3781 gnu_decl
3786 }
3792 gnat_entity);
3793 else
3794 {
3799 gnat_entity);
3802 }
3803 }
3814 /* If this type does not have a full view in the unit we are
3815 compiling, then just get the type from its Etype. */
3817 {
3818 /* If this is an incomplete type with no full view, it must be
3819 either a limited view brought in by a limited_with clause, in
3820 which case we use the non-limited view, or a Taft Amendement
3821 type, in which case we just return a dummy type. */
3823 {
3828 else
3830 }
3835 else
3836 {
3840 }
3843 }
3845 /* Otherwise, if we are not defining the type now, get the
3846 type from the full view. But always get the type from the full
3847 view for define on use types, since otherwise we won't see them! */
3854 {
3859 }
3861 /* For incomplete types, make a dummy type entry which will be
3862 replaced later. */
3865 /* Save this type as the full declaration's type so we can do any needed
3866 updates when we see it. */
3873 /* Simple class_wide types are always viewed as their root_type
3874 by Gigi unless an Equivalent_Type is specified. */
3878 else
3890 else
3902 /* Nothing at all to do here, so just return an ERROR_MARK and claim
3903 we've already saved it, so we don't try to. */
3910 }
3912 /* If we had a case where we evaluated another type and it might have
3913 defined this one, handle it here. */
3915 {
3918 }
3920 /* If we are processing a type and there is either no decl for it or
3921 we just made one, do some common processing for the type, such as
3922 handling alignment and possible padding. */
3925 {
3933 /* ??? Don't set the size for a String_Literal since it is either
3934 confirming or we don't handle it properly (if the low bound is
3935 non-constant). */
3941 /* If a size was specified, see if we can make a new type of that size
3942 by rearranging the type, for example from a fat to a thin pointer. */
3944 {
3945 gnu_type
3952 }
3954 /* If the alignment hasn't already been processed and this is
3955 not an unconstrained array, see if an alignment is specified.
3956 If not, we pick a default alignment for atomic objects. */
3958 ;
3972 /* See if we need to pad the type. If we did, and made a record,
3973 the name of the new type may be changed. So get it back for
3974 us when we make the new TYPE_DECL below. */
3979 {
3983 }
3987 /* If we are at global level, GCC will have applied variable_size to
3988 the type, but that won't have done anything. So, if it's not
3989 a constant or self-referential, call elaborate_expression_1 to
3990 make a variable for the size rather than calculating it each time.
3991 Handle both the RM size and the actual size. */
3996 {
4000 {
4007 }
4008 else
4009 {
4016 /* ??? For now, store the size as a multiple of the alignment
4017 in bytes so that we can see the alignment from the tree. */
4019 = build_binary_op
4021 elaborate_expression_1
4032 SET_TYPE_ADA_SIZE
4035 gnat_entity,
4039 }
4040 }
4042 /* If this is a record type or subtype, call elaborate_expression_1 on
4043 any field position. Do this for both global and local types.
4044 Skip any fields that we haven't made trees for to avoid problems with
4045 class wide types. */
4050 {
4053 /* ??? Unfortunately, GCC needs to be able to prove the
4054 alignment of this offset and if it's a variable, it can't.
4055 In GCC 3.4, we'll use DECL_OFFSET_ALIGN in some way, but
4056 right now, we have to put in an explicit multiply and
4057 divide by that value. */
4060 = build_binary_op
4062 elaborate_expression_1
4071 }
4075 | (TYPE_QUAL_VOLATILE
4088 else
4090 }
4093 {
4096 /* Back-annotate the Alignment of the type if not already in the
4097 tree. Likewise for sizes. */
4103 {
4104 /* If the size is self-referential, we annotate the maximum
4105 value of that size. */
4114 {
4115 /* In this mode the tag and the parent components are not
4116 generated by the front-end, so the sizes must be adjusted
4117 explicitly now. */
4123 {
4124 size_offset
4128 }
4129 else
4137 }
4138 }
4142 }
4152 /* If we haven't already, associate the ..._DECL node that we just made with
4153 the input GNAT entity node. */
4157 /* If this is an enumeral or floating-point type, we were not able to set
4158 the bounds since they refer to the type. These bounds are always static.
4160 For enumeration types, also write debugging information and declare the
4161 enumeration literal table, if needed. */
4165 {
4168 /* If this is a padded type, we need to use the underlying type. */
4173 /* If this is a floating point type and we haven't set a floating
4174 point type yet, use this in the evaluation of the bounds. */
4184 {
4187 /* Since this has both a typedef and a tag, avoid outputting
4188 the name twice. */
4191 }
4192 }
4194 /* If we deferred processing of incomplete types, re-enable it. If there
4195 were no other disables and we have some to process, do so. */
4197 {
4203 {
4210 }
4211 }
4213 /* If we are not defining this type, see if it's in the incomplete list.
4214 If so, handle that list entry now. */
4216 {
4221 {
4225 }
4226 }
4228 /* If there are no incomplete types and we have deferred emission
4229 of debug information, check whether we have finished defining
4230 all nested records.
4231 If so, handle the list now. */
4234 defer_debug_level--;
4237 && !defer_incomplete_level
4239 {
4245 {
4248 }
4251 }
4254 force_global--;
4263 }
4265 /* Similar, but if the returned value is a COMPONENT_REF, return the
4266 FIELD_DECL. */
4268 tree
4270 {
4277 }
4278 \f
4279 /* Given GNAT_ENTITY, elaborate all expressions that are required to
4280 be elaborated at the point of its definition, but do nothing else. */
4282 void
4284 {
4286 {
4293 {
4297 /* ??? Tests for avoiding static constraint error expression
4298 is needed until the front stops generating bogus conversions
4299 on bounds of real types. */
4308 }
4311 {
4315 /* If this is a record extension, go a level further to find the
4316 record definition. */
4319 }
4329 {
4330 Node_Id gnat_discriminant_expr;
4331 Entity_Id gnat_field;
4334 gnat_discriminant_expr
4339 /* ??? For now, ignore access discriminants. */
4342 gnat_entity,
4344 }
4347 }
4348 }
4349 \f
4350 /* Mark GNAT_ENTITY as going out of scope at this point. Recursively mark
4351 any entities on its entity chain similarly. */
4353 void
4355 {
4356 Entity_Id gnat_sub_entity;
4359 /* If this has an entity list, process all in the list. */
4376 /* Now clear this if it has been defined, but only do so if it isn't
4377 a subprogram or parameter. We could refine this, but it isn't
4378 worth it. If this is statically allocated, it is supposed to
4379 hang around out of cope. */
4382 {
4385 }
4386 }
4387 \f
4388 /* Set the alias set of GNU_NEW_TYPE to be that of GNU_OLD_TYPE. If this
4389 is a multi-dimensional array type, do this recursively. */
4391 static void
4393 {
4394 /* Remove any padding from GNU_OLD_TYPE. It doesn't matter in the case
4395 of a one-dimensional array, since the padding has the same alias set
4396 as the field type, but if it's a multi-dimensional array, we need to
4397 see the inner types. */
4403 /* We need to be careful here in case GNU_OLD_TYPE is an unconstrained
4404 array. In that case, it doesn't have the same shape as GNU_NEW_TYPE,
4405 so we need to go down to what does. */
4407 gnu_old_type
4417 }
4418 \f
4419 /* Return a TREE_LIST describing the substitutions needed to reflect
4420 discriminant substitutions from GNAT_SUBTYPE to GNAT_TYPE and add
4421 them to GNU_LIST. If GNAT_TYPE is not specified, use the base type
4422 of GNAT_SUBTYPE. The substitutions can be in any order. TREE_PURPOSE
4423 gives the tree for the discriminant and TREE_VALUES is the replacement
4424 value. They are in the form of operands to substitute_in_expr.
4425 DEFINITION is as in gnat_to_gnu_entity. */
4427 static tree
4430 {
4431 Entity_Id gnat_discrim;
4432 Node_Id gnat_value;
4443 /* Ignore access discriminants. */
4446 elaborate_expression
4450 gnu_list);
4453 }
4454 \f
4455 /* For the following two functions: for each GNAT entity, the GCC
4456 tree node used as a dummy for that entity, if any. */
4460 /* Initialize the above table. */
4462 void
4464 {
4465 Node_Id gnat_node;
4473 }
4475 /* Make a dummy type corresponding to GNAT_TYPE. */
4477 tree
4479 {
4480 Entity_Id gnat_underlying;
4481 tree gnu_type;
4483 /* Find a full type for GNAT_TYPE, taking into account any class wide
4484 types. */
4494 ;
4496 /* If it there already a dummy type, use that one. Else make one. */
4500 /* If this is a record, make this a RECORD_TYPE or UNION_TYPE; else make
4501 it a VOID_TYPE. */
4503 {
4506 }
4509 else
4520 }
4521 \f
4522 /* Return true if the size represented by GNU_SIZE can be handled by an
4523 allocation. If STATIC_P is true, consider only what can be done with a
4524 static allocation. */
4526 static bool
4528 {
4529 HOST_WIDE_INT our_size;
4531 /* If this is not a static allocation, the only case we want to forbid
4532 is an overflowing size. That will be converted into a raise a
4533 Storage_Error. */
4538 /* Otherwise, we need to deal with both variable sizes and constant
4539 sizes that won't fit in a host int. We use int instead of HOST_WIDE_INT
4540 since assemblers may not like very large sizes. */
4546 }
4547 \f
4548 /* Prepend to ATTR_LIST the list of attributes for GNAT_ENTITY, if any. */
4550 static void
4552 {
4553 Node_Id gnat_temp;
4558 {
4568 {
4570 (gnat_to_gnu
4577 (gnat_to_gnu
4578 (Expression
4581 }
4584 {
4611 }
4618 /* If we have an argument specified together with an attribute name,
4619 make it a single TREE_VALUE entry in a list of arguments, as GCC
4620 expects it. */
4623 else
4626 attr->error_point
4630 }
4631 }
4632 \f
4633 /* Get the unpadded version of a GNAT type. */
4635 tree
4637 {
4644 }
4645 \f
4646 /* Called when we need to protect a variable object using a save_expr. */
4648 tree
4650 {
4657 {
4665 }
4666 else
4668 }
4669 \f
4670 /* Given a GNAT tree GNAT_EXPR, for an expression which is a value within a
4671 type definition (either a bound or a discriminant value) for GNAT_ENTITY,
4672 return the GCC tree to use for that expression. GNU_NAME is the
4673 qualification to use if an external name is appropriate and DEFINITION is
4674 nonzero if this is a definition of GNAT_ENTITY. If NEED_VALUE is nonzero,
4675 we need a result. Otherwise, we are just elaborating this for
4676 side-effects. If NEED_DEBUG is nonzero we need the symbol for debugging
4677 purposes even if it isn't needed for code generation. */
4679 static tree
4683 {
4684 tree gnu_expr;
4686 /* If we already elaborated this expression (e.g., it was involved
4687 in the definition of a private type), use the old value. */
4691 /* If we don't need a value and this is static or a discriment, we
4692 don't need to do anything. */
4699 /* Otherwise, convert this tree to its GCC equivalent. */
4700 gnu_expr
4704 /* Save the expression in case we try to elaborate this entity again. Since
4705 this is not a DECL, don't check it. Don't save if it's a discriminant. */
4710 }
4712 /* Similar, but take a GNU expression. */
4714 static tree
4718 {
4720 /* Strip any conversions to see if the expression is a readonly variable.
4721 ??? This really should remain readonly, but we have to think about
4722 the typing of the tree here. */
4727 /* In most cases, we won't see a naked FIELD_DECL here because a
4728 discriminant reference will have been replaced with a COMPONENT_REF
4729 when the type is being elaborated. However, there are some cases
4730 involving child types where we will. So convert it to a COMPONENT_REF
4731 here. We have to hope it will be at the highest level of the
4732 expression in these cases. */
4738 /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
4739 that is a constant, make a variable that is initialized to contain the
4740 bound when the package containing the definition is elaborated. If
4741 this entity is defined at top level and a bound or discriminant value
4742 isn't a constant or a reference to a discriminant, replace the bound
4743 by the variable; otherwise use a SAVE_EXPR if needed. Note that we
4744 rely here on the fact that an expression cannot contain both the
4745 discriminant and some other variable. */
4752 /* If this is a static expression or contains a discriminant, we don't
4753 need the variable for debugging (and can't elaborate anyway if a
4754 discriminant). */
4760 /* Now create the variable if we need it. */
4762 gnu_decl
4769 /* We only need to use this variable if we are in global context since GCC
4770 can do the right thing in the local case. */
4775 else
4777 }
4778 \f
4779 /* Create a record type that contains a field of TYPE with a starting bit
4780 position so that it is aligned to ALIGN bits and is SIZE bytes long. */
4782 tree
4784 {
4789 place));
4798 /* The bit position is obtained by "and"ing the alignment minus 1
4799 with the two's complement of the address and multiplying
4800 by the number of bits per unit. Do all this in sizetype. */
4805 size_addr_place),
4808 bitsize_unit_node);
4810 /* Create the field, with -1 as the 'addressable' indication to avoid the
4811 creation of a bitfield. We don't need one, it would have damaging
4812 consequences on the alignment computation, and create_field_decl would
4813 make one without this special argument, for instance because of the
4814 complex position expression. */
4823 bitsize_unit_node),
4829 }
4830 \f
4831 /* TYPE is a RECORD_TYPE, UNION_TYPE, or QUAL_UNION_TYPE, with BLKmode that's
4832 being used as the field type of a packed record. See if we can rewrite it
4833 as a record that has a non-BLKmode type, which we can pack tighter. If so,
4834 return the new type. If not, return the original type. */
4836 static tree
4838 {
4841 tree old_field;
4843 /* Copy the name and flags from the old type to that of the new and set
4844 the alignment to try for an integral type. For QUAL_UNION_TYPE,
4845 also copy the size. */
4854 {
4857 }
4863 /* Now copy the fields, keeping the position and size. */
4866 {
4868 tree new_field;
4884 SET_DECL_ORIGINAL_FIELD
4893 }
4898 }
4899 \f
4900 /* Ensure that TYPE has SIZE and ALIGN. Make and return a new padded type
4901 if needed. We have already verified that SIZE and TYPE are large enough.
4903 GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
4904 to issue a warning.
4906 IS_USER_TYPE is true if we must be sure we complete the original type.
4908 DEFINITION is true if this type is being defined.
4910 SAME_RM_SIZE is true if the RM_Size of the resulting type is to be
4911 set to its TYPE_SIZE; otherwise, it's set to the RM_Size of the original
4912 type. */
4914 tree
4918 {
4920 tree record;
4921 tree field;
4923 /* If TYPE is a padded type, see if it agrees with any size and alignment
4924 we were given. If so, return the original type. Otherwise, strip
4925 off the padding, since we will either be returning the inner type
4926 or repadding it. If no size or alignment is specified, use that of
4927 the original padded type. */
4930 {
4947 }
4949 /* If the size is either not being changed or is being made smaller (which
4950 is not done here (and is only valid for bitfields anyway), show the size
4951 isn't changing. Likewise, clear the alignment if it isn't being
4952 changed. Then return if we aren't doing anything. */
4966 /* We used to modify the record in place in some cases, but that could
4967 generate incorrect debugging information. So make a new record
4968 type and name. */
4974 /* If we were making a type, complete the original type and give it a
4975 name. */
4982 gnat_entity);
4984 /* If we are changing the alignment and the input type is a record with
4985 BLKmode and a small constant size, try to make a form that has an
4986 integral mode. That might allow this record to have an integral mode,
4987 which will be much more efficient. There is no point in doing this if a
4988 size is specified unless it is also smaller than the biggest alignment
4989 and it is incorrect to do this if the size of the original type is not a
4990 multiple of the alignment. */
4996 && (!size
5018 /* Keep the RM_Size of the padded record as that of the old record
5019 if requested. */
5022 /* Unless debugging information isn't being written for the input type,
5023 write a record that shows what we are a subtype of and also make a
5024 variable that indicates our size, if variable. */
5028 {
5049 }
5056 /* If the size was widened explicitly, maybe give a warning. */
5062 {
5075 /* Generate message only for entities that come from source, since
5076 if we have an entity created by expansion, the message will be
5077 generated for some other corresponding source entity. */
5080 gnat_entity,
5087 }
5090 }
5091 \f
5092 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
5093 the value passed against the list of choices. */
5095 tree
5097 {
5098 Node_Id choice;
5099 Node_Id gnat_temp;
5104 {
5106 {
5111 /* There's no good type to use here, so we might as well use
5112 integer_type_node. */
5113 this_test
5127 this_test
5137 /* This represents either a subtype range, an enumeration
5138 literal, or a constant Ekind says which. If an enumeration
5139 literal or constant, fall through to the next case. */
5142 {
5148 this_test
5155 }
5156 /* ... fall through ... */
5161 single);
5170 }
5174 }
5177 }
5178 \f
5179 /* Return a GCC tree for a field corresponding to GNAT_FIELD to be
5180 placed in GNU_RECORD_TYPE.
5182 PACKED is 1 if the enclosing record is packed and -1 if the enclosing
5183 record has a Component_Alignment of Storage_Unit.
5185 DEFINITION is true if this field is for a record being defined. */
5187 static tree
5190 {
5195 tree gnu_field;
5196 bool needs_strict_alignment
5200 /* If this field requires strict alignment or contains an item of
5201 variable sized, pretend it isn't packed. */
5205 /* For packed records, this is one of the few occasions on which we use
5206 the official RM size for discrete or fixed-point components, instead
5207 of the normal GNAT size stored in Esize. See description in Einfo:
5208 "Handling of Type'Size Values" for further details. */
5218 /* If we are packing this record, have a specified size that's smaller than
5219 that of the field type, or a position is specified, and the field type is
5220 also a record that's BLKmode and with a small constant size, see if we
5221 can get a better form of the type that allows more packing. If we can,
5222 show a size was specified for it if there wasn't one so we know to make
5223 this a bitfield and avoid making things wider. */
5229 || (gnu_size
5232 {
5233 /* See what the alternate type and size would be. */
5236 /* Compute whether we should avoid the substitution. */
5238 /* There is no point substituting if there is no change. */
5240 ||
5241 /* The size of an aliased field must be an exact multiple of the
5242 type's alignment, which the substitution might increase. Reject
5243 substitutions that would so invalidate a component clause when the
5244 specified position is byte aligned, as the change would have no
5245 real benefit from the packing standpoint anyway. */
5250 );
5252 /* Substitute unless told otherwise. */
5254 {
5259 }
5260 }
5262 /* If we are packing the record and the field is BLKmode, round the
5263 size up to a byte boundary. */
5268 {
5273 /* Ensure the position does not overlap with the parent subtype,
5274 if there is one. */
5276 {
5277 tree gnu_parent
5283 {
5284 post_error_ne_tree
5288 }
5289 }
5291 /* If this field needs strict alignment, ensure the record is
5292 sufficiently aligned and that that position and size are
5293 consistent with the alignment. */
5295 {
5302 /* If Atomic, the size must match exactly that of the field. */
5305 {
5306 post_error_ne_tree
5312 }
5314 /* If Aliased, the size must match exactly the rounded size. We
5315 used to be more accommodating here and accept greater sizes, but
5316 fully supporting this case on big-endian platforms would require
5317 switching to a more involved layout for the field. */
5319 && gnu_size
5321 {
5322 post_error_ne_tree
5325 gnu_rounded_size);
5327 }
5332 {
5334 post_error_ne_num
5340 post_error_ne_num
5346 post_error_ne_num
5350 else
5354 }
5355 }
5359 }
5361 /* If the record has rep clauses and this is the tag field, make a rep
5362 clause for it as well. */
5365 {
5368 }
5370 /* We need to make the size the maximum for the type if it is
5371 self-referential and an unconstrained type. In that case, we can't
5372 pack the field since we can't make a copy to align it. */
5374 && !gnu_size
5377 {
5380 }
5382 /* If no size is specified (or if there was an error), don't specify a
5383 position. */
5386 else
5387 {
5388 /* If the field's type is justified modular, we would need to remove
5389 the wrapper to (better) meet the layout requirements. However we
5390 can do so only if the field is not aliased to preserve the unique
5391 layout and if the prescribed size is not greater than that of the
5392 packed array to preserve the justification. */
5400 gnu_field_type
5405 }
5410 /* Now create the decl for the field. */
5422 }
5423 \f
5424 /* Return true if TYPE is a type with variable size, a padding type with a
5425 field of variable size or is a record that has a field such a field. */
5427 static bool
5429 {
5430 tree field;
5432 /* We need not be concerned about this at all if we don't have
5433 strict alignment. */
5451 }
5452 \f
5453 /* Return a GCC tree for a record type given a GNAT Component_List and a chain
5454 of GCC trees for fields that are in the record and have already been
5455 processed. When called from gnat_to_gnu_entity during the processing of a
5456 record type definition, the GCC nodes for the discriminants will be on
5457 the chain. The other calls to this function are recursive calls from
5458 itself for the Component_List of a variant and the chain is empty.
5460 PACKED is 1 if this is for a record with "pragma pack" and -1 is this is
5461 for a record type with "pragma component_alignment (storage_unit)".
5463 DEFINITION is true if we are defining this record.
5465 P_GNU_REP_LIST, if nonzero, is a pointer to a list to which each field
5466 with a rep clause is to be added. If it is nonzero, that is all that
5467 should be done with such fields.
5469 CANCEL_ALIGNMENT, if true, means the alignment should be zeroed before
5470 laying out the record. This means the alignment only serves to force fields
5471 to be bitfields, but not require the record to be that aligned. This is
5472 used for variants.
5474 ALL_REP, if true, means a rep clause was found for all the fields. This
5475 simplifies the logic since we know we're not in the mixed case.
5477 DEFER_DEBUG, if true, means that the debugging routines should not be
5478 called when finishing constructing the record type.
5480 The processing of the component list fills in the chain with all of the
5481 fields of the record and then the record type is finished. */
5483 static void
5488 {
5489 Node_Id component_decl;
5490 Entity_Id gnat_field;
5491 Node_Id variant_part;
5492 Node_Id variant;
5498 /* For each variable within each component declaration create a GCC field
5499 and add it to the list, skipping any pragmas in the list. */
5505 {
5510 else
5511 {
5515 /* If this is the _Tag field, put it before any discriminants,
5516 instead of after them as is the case for all other fields.
5517 Ignore field of void type if only annotating. */
5520 else
5521 {
5524 }
5525 }
5528 }
5530 /* At the end of the component list there may be a variant part. */
5533 /* If this is an unchecked union, each variant must have exactly one
5534 component, each of which becomes one component of this union. */
5541 {
5542 component_decl
5546 definition);
5550 }
5552 /* We create a QUAL_UNION_TYPE for the variant part since the variants are
5553 mutually exclusive and should go in the same memory. To do this we need
5554 to treat each variant as a record whose elements are created from the
5555 component list for the variant. So here we create the records from the
5556 lists for the variants and put them all into the QUAL_UNION_TYPE. */
5558 {
5560 Node_Id variant;
5562 tree gnu_union_field;
5565 tree gnu_var_name
5566 = concat_id_with_name
5580 {
5582 tree gnu_inner_name;
5583 tree gnu_qual;
5591 /* Set the alignment of the inner type in case we need to make
5592 inner objects into bitfields, but then clear it out
5593 so the record actually gets only the alignment required. */
5597 /* Similarly, if the outer record has a size specified and all fields
5598 have record rep clauses, we can propagate the size into the
5599 variant part. */
5601 {
5605 }
5618 (all_rep_and_size
5620 (all_rep_and_size
5628 }
5630 /* We use to delete the empty variants from the end. However,
5631 we no longer do that because we need them to generate complete
5632 debugging information for the variant record. Otherwise,
5633 the union type definition will be missing the fields associated
5634 to these empty variants. */
5636 /* Only make the QUAL_UNION_TYPE if there are any non-empty variants. */
5638 {
5640 {
5644 }
5649 gnu_union_field
5651 packed,
5658 }
5659 }
5661 /* Scan GNU_FIELD_LIST and see if any fields have rep clauses. If they
5662 do, pull them out and put them into GNU_OUR_REP_LIST. We have to do this
5663 in a separate pass since we want to handle the discriminants but can't
5664 play with them until we've used them in debugging data above.
5666 ??? Note: if we then reorder them, debugging information will be wrong,
5667 but there's nothing that can be done about this at the moment. */
5670 {
5672 {
5677 else
5683 }
5684 else
5685 {
5688 }
5689 }
5691 /* If we have any items in our rep'ed field list, it is not the case that all
5692 the fields in the record have rep clauses, and P_REP_LIST is nonzero,
5693 set it and ignore the items. */
5697 {
5698 /* Otherwise, sort the fields by bit position and put them into their
5699 own record if we have any fields without rep clauses. */
5700 tree gnu_rep_type
5712 /* Put the fields in the list in order of increasing position, which
5713 means we start from the end. */
5716 {
5720 }
5723 {
5729 }
5730 else
5731 {
5734 }
5735 }
5742 }
5743 \f
5744 /* Called via qsort from the above. Returns -1, 1, depending on the
5745 bit positions and ordinals of the two fields. Use DECL_UID to ensure
5746 a stable sort. */
5748 static int
5750 {
5758 else
5760 }
5761 \f
5762 /* Given GNU_SIZE, a GCC tree representing a size, return a Uint to be
5763 placed into an Esize, Component_Bit_Offset, or Component_Size value
5764 in the GNAT tree. */
5766 static Uint
5768 {
5770 TCode tcode;
5775 /* See if we've already saved the value for this node. */
5779 /* If we do not return inside this switch, TCODE will be set to the
5780 code to use for a Create_Node operand and LEN (set above) will be
5781 the number of recursive calls for us to make. */
5784 {
5789 /* This may have come from a conversion from some smaller type,
5790 so ensure this is in bitsizetype. */
5793 /* For negative values, use NEGATE_EXPR of the supplied value. */
5795 {
5796 /* The ridiculous code below is to handle the case of the largest
5797 negative integer. */
5800 tree temp;
5803 {
5804 negative_size
5807 bitsize_one_node));
5809 }
5816 }
5823 /* This peculiar test is to make sure that the size fits in an int
5824 on machines where HOST_WIDE_INT is not "int". */
5827 else
5831 /* The only case we handle here is a simple discriminant reference. */
5839 else
5845 /* Now just list the operations we handle. */
5877 }
5879 /* Now get each of the operands that's relevant for this code. If any
5880 cannot be expressed as a repinfo node, say we can't. */
5885 {
5889 }
5894 }
5896 /* Given GNAT_ENTITY, a record type, and GNU_TYPE, its corresponding
5897 GCC type, set Component_Bit_Offset and Esize to the position and size
5898 used by Gigi. */
5900 static void
5902 {
5903 tree gnu_list;
5904 tree gnu_entry;
5905 Entity_Id gnat_field;
5907 /* We operate by first making a list of all fields and their positions
5908 (we can get the sizes easily at any time) by a recursive call
5909 and then update all the sizes into the tree. */
5912 BIGGEST_ALIGNMENT);
5919 {
5923 gnu_list);
5926 {
5928 {
5929 /* In this mode the tag and parent components have not been
5930 generated, so we add the appropriate offset to each
5931 component. For a component appearing in the current
5932 extension, the offset is the size of the parent. */
5935 parent_offset
5937 bitsizetype);
5938 else
5940 }
5942 Set_Component_Bit_Offset
5944 annotate_value
5949 parent_offset)));
5953 }
5956 {
5957 /* If there is no gnu_entry, this is an inherited component whose
5958 position is the same as in the parent type. */
5959 Set_Component_Bit_Offset
5964 }
5965 }
5966 }
5968 /* Scan all fields in GNU_TYPE and build entries where TREE_PURPOSE is the
5969 FIELD_DECL and TREE_VALUE a TREE_LIST with TREE_PURPOSE being the byte
5970 position and TREE_VALUE being a TREE_LIST with TREE_PURPOSE the value to be
5971 placed into DECL_OFFSET_ALIGN and TREE_VALUE the bit position. GNU_POS is
5972 to be added to the position, GNU_BITPOS to the bit position, OFFSET_ALIGN is
5973 the present value of DECL_OFFSET_ALIGN and GNU_LIST is a list of the entries
5974 so far. */
5976 static tree
5979 {
5980 tree gnu_field;
5985 {
5990 unsigned int our_offset_align
5993 gnu_result
5998 NULL_TREE),
5999 gnu_result);
6002 gnu_result
6005 our_offset_align);
6006 }
6009 }
6010 \f
6011 /* UINT_SIZE is a Uint giving the specified size for an object of GNU_TYPE
6012 corresponding to GNAT_OBJECT. If size is valid, return a tree corresponding
6013 to its value. Otherwise return 0. KIND is VAR_DECL is we are specifying
6014 the size for an object, TYPE_DECL for the size of a type, and FIELD_DECL
6015 for the size of a field. COMPONENT_P is true if we are being called
6016 to process the Component_Size of GNAT_OBJECT. This is used for error
6017 message handling and to indicate to use the object size of GNU_TYPE.
6018 ZERO_OK is true if a size of zero is permitted; if ZERO_OK is false,
6019 it means that a size of zero should be treated as an unspecified size. */
6021 static tree
6024 {
6025 Node_Id gnat_error_node;
6026 tree type_size
6028 tree size;
6030 /* Find the node to use for errors. */
6037 else
6040 /* Return 0 if no size was specified, either because Esize was not Present or
6041 the specified size was zero. */
6045 /* Get the size as a tree. Give an error if a size was specified, but cannot
6046 be represented as in sizetype. */
6049 {
6054 }
6056 /* Ignore a negative size since that corresponds to our back-annotation.
6057 Also ignore a zero size unless a size clause exists. */
6061 /* The size of objects is always a multiple of a byte. */
6064 {
6068 else
6072 }
6074 /* If this is an integral type or a packed array type, the front-end has
6075 verified the size, so we need not do it here (which would entail
6076 checking against the bounds). However, if this is an aliased object, it
6077 may not be smaller than the type of the object. */
6082 /* If the object is a record that contains a template, add the size of
6083 the template to the specified size. */
6088 /* Modify the size of the type to be that of the maximum size if it has a
6089 discriminant or the size of a thin pointer if this is a fat pointer. */
6095 /* If this is an access type, the minimum size is that given by the smallest
6096 integral mode that's valid for pointers. */
6098 {
6104 ;
6107 }
6109 /* If the size of the object is a constant, the new size must not be
6110 smaller. */
6114 {
6116 post_error_ne_tree
6119 else
6126 post_error_ne_tree_2
6136 }
6139 }
6140 \f
6141 /* Similarly, but both validate and process a value of RM_Size. This
6142 routine is only called for types. */
6144 static void
6146 {
6147 /* Only give an error if a Value_Size clause was explicitly given.
6148 Otherwise, we'd be duplicating an error on the Size clause. */
6149 Node_Id gnat_attr_node
6152 tree size;
6154 /* Get the size as a tree. Do nothing if none was specified, either
6155 because RM_Size was not Present or if the specified size was zero.
6156 Give an error if a size was specified, but cannot be represented as
6157 in sizetype. */
6163 {
6166 gnat_entity);
6169 }
6171 /* Ignore a negative size since that corresponds to our back-annotation.
6172 Also ignore a zero size unless a size clause exists, a Value_Size
6173 clause exists, or this is an integer type, in which case the
6174 front end will have always set it. */
6181 /* If the old size is self-referential, get the maximum size. */
6185 /* If the size of the object is a constant, the new size must not be
6186 smaller (the front end checks this for scalar types). */
6191 {
6193 post_error_ne_tree
6198 }
6200 /* Otherwise, set the RM_Size. */
6211 }
6212 \f
6213 /* Given a type TYPE, return a new type whose size is appropriate for SIZE.
6214 If TYPE is the best type, return it. Otherwise, make a new type. We
6215 only support new integral and pointer types. BIASED_P is nonzero if
6216 we are making a biased type. */
6218 static tree
6220 {
6221 tree new_type;
6225 /* If size indicates an error, just return TYPE to avoid propagating the
6226 error. Likewise if it's too large to represent. */
6232 {
6235 /* Only do something if the type is not already the proper size and is
6236 not a packed array type. */
6248 new_type
6260 /* Do something if this is a fat pointer, in which case we
6261 may need to return the thin pointer. */
6263 return
6264 build_pointer_type
6269 /* Only do something if this is a thin pointer, in which case we
6270 may need to return the fat pointer. */
6272 return
6279 }
6282 }
6283 \f
6284 /* ALIGNMENT is a Uint giving the alignment specified for GNAT_ENTITY,
6285 a type or object whose present alignment is ALIGN. If this alignment is
6286 valid, return it. Otherwise, give an error and return ALIGN. */
6288 static unsigned int
6290 {
6294 #ifndef MAX_OFILE_ALIGNMENT
6295 #define MAX_OFILE_ALIGNMENT BIGGEST_ALIGNMENT
6296 #endif
6301 /* Don't worry about checking alignment if alignment was not specified
6302 by the source program and we already posted an error for this entity. */
6307 /* Within GCC, an alignment is an integer, so we must make sure a
6308 value is specified that fits in that range. Also, alignments of
6309 more than MAX_OFILE_ALIGNMENT can't be supported. */
6323 else
6327 }
6328 \f
6329 /* Verify that OBJECT, a type or decl, is something we can implement
6330 atomically. If not, give an error for GNAT_ENTITY. COMP_P is true
6331 if we require atomic components. */
6333 static void
6335 {
6337 Node_Id gnat_node;
6340 tree size;
6342 /* There are three case of what OBJECT can be. It can be a type, in which
6343 case we take the size, alignment and mode from the type. It can be a
6344 declaration that was indirect, in which case the relevant values are
6345 that of the type being pointed to, or it can be a normal declaration,
6346 in which case the values are of the decl. The code below assumes that
6347 OBJECT is either a type or a decl. */
6349 {
6353 }
6355 {
6359 }
6360 else
6361 {
6365 }
6367 /* Consider all floating-point types atomic and any types that that are
6368 represented by integers no wider than a machine word. */
6375 /* For the moment, also allow anything that has an alignment equal
6376 to its size and which is smaller than a word. */
6384 {
6392 }
6397 else
6400 }
6401 \f
6402 /* Check if FTYPE1 and FTYPE2, two potentially different function type nodes,
6403 have compatible signatures so that a call using one type may be safely
6404 issued if the actual target function type is the other. Return 1 if it is
6405 the case, 0 otherwise, and post errors on the incompatibilities.
6407 This is used when an Ada subprogram is mapped onto a GCC builtin, to ensure
6408 that calls to the subprogram will have arguments suitable for the later
6409 underlying builtin expansion. */
6411 static int
6413 {
6414 /* As of now, we only perform very trivial tests and consider it's the
6415 programmer's responsibility to ensure the type correctness in the Ada
6416 declaration, as in the regular Import cases.
6418 Mismatches typically result in either error messages from the builtin
6419 expander, internal compiler errors, or in a real call sequence. This
6420 should be refined to issue diagnostics helping error detection and
6421 correction. */
6423 /* Almost fake test, ensuring a use of each argument. */
6428 }
6429 \f
6430 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new type
6431 with all size expressions that contain F updated by replacing F with R.
6432 This is identical to GCC's substitute_in_type except that it knows about
6433 TYPE_INDEX_TYPE. If F is NULL_TREE, always make a new RECORD_TYPE, even if
6434 nothing has changed. */
6436 tree
6438 {
6440 tree tem;
6443 {
6450 {
6459 SET_TYPE_INDEX_TYPE
6462 }
6469 {
6483 }
6497 /* Don't know how to do these yet. */
6501 {
6515 /* If we had bounded the sizes of T by a constant, bound the sizes of
6516 NEW by the same constant. */
6526 }
6531 {
6532 tree field;
6533 bool changed_field
6540 /* Start out with no fields, make new fields, and chain them
6541 in. If we haven't actually changed the type of any field,
6542 discard everything we've done and return the old type. */
6548 {
6559 /* If this is an internal field and the type of this field is
6560 a UNION_TYPE or RECORD_TYPE with no elements, ignore it. If
6561 the type just has one element, treat that as the field.
6562 But don't do this if we are processing a QUAL_UNION_TYPE. */
6567 {
6572 {
6573 tree next_new_field
6576 /* Make sure omitting the union doesn't change
6577 the layout. */
6580 }
6581 }
6588 /* If the size of the old field was set at a constant,
6589 propagate the size in case the type's size was variable.
6590 (This occurs in the case of a variant or discriminated
6591 record with a default size used as a field of another
6592 record.) */
6601 {
6607 /* Do the substitution inside the qualifier and if we find
6608 that this field will not be present, omit it. */
6613 }
6617 else
6622 /* If this is a qualified type and this field will always be
6623 present, we are done. */
6627 }
6629 /* If this used to be a qualified union type, but we now know what
6630 field will be present, make this a normal union. */
6641 /* If the size was originally a constant use it. */
6644 {
6648 }
6651 }
6655 }
6656 }
6657 \f
6658 /* Return the "RM size" of GNU_TYPE. This is the actual number of bits
6659 needed to represent the object. */
6661 tree
6663 {
6664 /* For integer types, this is the precision. For record types, we store
6665 the size explicitly. For other types, this is just the size. */
6671 /* Return the rm_size of the actual data plus the size of the template. */
6672 return
6682 else
6684 }
6685 \f
6686 /* Return an identifier representing the external name to be used for
6687 GNAT_ENTITY. If SUFFIX is specified, the name is followed by "___"
6688 and the specified suffix. */
6690 tree
6692 {
6701 /* A variable using the Stdcall convention (meaning we are running
6702 on a Windows box) live in a DLL. Here we adjust its name to use
6703 the jump-table, the _imp__NAME contains the address for the NAME
6704 variable. */
6707 {
6714 }
6717 }
6719 /* Return the name to be used for GNAT_ENTITY. If a type, create a
6720 fully-qualified name, possibly with type information encoding.
6721 Otherwise, return the name. */
6723 tree
6725 {
6728 }
6730 /* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
6731 string, return a new IDENTIFIER_NODE that is the concatenation of
6732 the name in GNU_ID and SUFFIX. */
6734 tree
6736 {
6745 }