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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- F R E E Z E --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2023, 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 3, 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 COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
82 -----------------------
83 -- Local Subprograms --
84 -----------------------
87 -- Typ is a type that is being frozen. If no size clause is given,
88 -- but a default Esize has been computed, then this default Esize is
89 -- adjusted up if necessary to be consistent with a given alignment,
90 -- but never to a value greater than System_Max_Integer_Size. This is
91 -- used for all discrete types and for fixed-point types.
93 procedure Build_And_Analyze_Renamed_Body
97 -- Build body for a renaming declaration, insert in tree and analyze
100 -- Apply legality checks to address clauses for object declarations,
101 -- at the point the object is frozen. Also ensure any initialization is
102 -- performed only after the object has been frozen.
104 procedure Check_Component_Storage_Order
109 -- For an Encl_Type that has a Scalar_Storage_Order attribute definition
110 -- clause, verify that the component type has an explicit and compatible
111 -- attribute/aspect. For arrays, Comp is Empty; for records, it is the
112 -- entity of the component under consideration. For an Encl_Type that
113 -- does not have a Scalar_Storage_Order attribute definition clause,
114 -- verify that the component also does not have such a clause.
115 -- ADC is the attribute definition clause if present (or Empty). On return,
116 -- Comp_ADC_Present is set True if the component has a Scalar_Storage_Order
117 -- attribute definition clause.
120 -- As each entity is frozen, this routine is called to deal with the
121 -- setting of Debug_Info_Needed for the entity. This flag is set if
122 -- the entity comes from source, or if we are in Debug_Generated_Code
123 -- mode or if the -gnatdV debug flag is set. However, it never sets
124 -- the flag if Debug_Info_Off is set. This procedure also ensures that
125 -- subsidiary entities have the flag set as required.
128 -- When an expression function is frozen by a use of it, the expression
129 -- itself is frozen. Check that the expression does not include references
130 -- to deferred constants without completion. We report this at the freeze
131 -- point of the function, to provide a better error message.
132 --
133 -- In most cases the expression itself is frozen by the time the function
134 -- itself is frozen, because the formals will be frozen by then. However,
135 -- Attribute references to outer types are freeze points for those types;
136 -- this routine generates the required freeze nodes for them.
139 -- E is a base type. If E is tagged or has a component that is aliased
140 -- or tagged or contains something this is aliased or tagged, set
141 -- Strict_Alignment.
145 -- If E is a fixed-point or discrete type, then all the necessary work
146 -- to freeze it is completed except for possible setting of the flag
147 -- Is_Unsigned_Type, which is done by this procedure. The call has no
148 -- effect if the entity E is not a discrete or fixed-point type.
150 procedure Freeze_And_Append
154 -- Freezes Ent using Freeze_Entity, and appends the resulting list of
155 -- nodes to Result, modifying Result from No_List if necessary. N has
156 -- the same usage as in Freeze_Entity.
159 -- Freeze enumeration type. The Esize field is set as processing
160 -- proceeds (i.e. set by default when the type is declared and then
161 -- adjusted by rep clauses). What this procedure does is to make sure
162 -- that if a foreign convention is specified, and no specific size
163 -- is given, then the size must be at least Integer'Size.
166 -- If an object is frozen which has Is_Statically_Allocated set, then
167 -- all referenced types must also be marked with this flag. This routine
168 -- is in charge of meeting this requirement for the object entity E.
171 -- Perform freezing actions for a subprogram (create extra formals,
172 -- and set proper default mechanism values). Note that this routine
173 -- is not called for internal subprograms, for which neither of these
174 -- actions is needed (or desirable, we do not want for example to have
175 -- these extra formals present in initialization procedures, where they
176 -- would serve no purpose). In this call E is either a subprogram or
177 -- a subprogram type (i.e. an access to a subprogram).
180 -- True if T is not private and has no private components, or has a full
181 -- view. Used to determine whether the designated type of an access type
182 -- should be frozen when the access type is frozen. This is done when an
183 -- allocator is frozen, or an expression that may involve attributes of
184 -- the designated type. Otherwise freezing the access type does not freeze
185 -- the designated type.
187 function Should_Freeze_Type
189 -- If Typ is in the current scope, then return True.
190 -- N is a node whose source location corresponds to the freeze point.
191 -- ??? Expression functions (represented by E) shouldn't freeze types in
192 -- general, but our current expansion and freezing model requires an early
193 -- freezing when the dispatch table is needed or when building an aggregate
194 -- with a subtype of Typ, so return True also in this case.
195 -- Note that expression function completions do freeze and are
196 -- handled in Sem_Ch6.Analyze_Expression_Function.
198 ------------------------
199 -- Should_Freeze_Type --
200 ------------------------
202 function Should_Freeze_Type
204 is
205 function Is_Dispatching_Call_Or_Aggregate
207 -- Return Abandon if N is a dispatching call to a subprogram
208 -- declared in the same scope as Typ or an aggregate whose type
209 -- is Typ.
211 --------------------------------------
212 -- Is_Dispatching_Call_Or_Aggregate --
213 --------------------------------------
215 function Is_Dispatching_Call_Or_Aggregate
217 begin
222 then
226 then
228 else
233 -------------------------
234 -- Need_Dispatch_Table --
235 -------------------------
239 -- Return Abandon if the input expression requires access to
240 -- Typ's dispatch table.
245 -- Start of processing for Should_Freeze_Type
247 begin
256 procedure Process_Default_Expressions
259 -- This procedure is called for each subprogram to complete processing of
260 -- default expressions at the point where all types are known to be frozen.
261 -- The expressions must be analyzed in full, to make sure that all error
262 -- processing is done (they have only been preanalyzed). If the expression
263 -- is not an entity or literal, its analysis may generate code which must
264 -- not be executed. In that case we build a function body to hold that
265 -- code. This wrapper function serves no other purpose (it used to be
266 -- called to evaluate the default, but now the default is inlined at each
267 -- point of call).
270 -- Typ is a record or array type that is being frozen. This routine sets
271 -- the default component alignment from the scope stack values if the
272 -- alignment is otherwise not specified.
275 -- T is a record or array type that is being frozen. If it is a base type,
276 -- and if SSO_Set_Low/High_By_Default is set, then Reverse_Storage order
277 -- will be set appropriately. Note that an explicit occurrence of aspect
278 -- Scalar_Storage_Order or an explicit setting of this aspect with an
279 -- attribute definition clause occurs, then these two flags are reset in
280 -- any case, so call will have no effect.
283 -- T is a type of a component that we know to be an Itype. We don't want
284 -- this to have a Freeze_Node, so ensure it doesn't. Do the same for any
285 -- Full_View or Corresponding_Record_Type.
288 -- Expr is the expression for an address clause for the entity denoted by
289 -- Nam whose type is Typ. If Typ has a default initialization, and there is
290 -- no explicit initialization in the source declaration, check whether the
291 -- address clause might cause overlaying of an entity, and emit a warning
292 -- on the side effect that the initialization will cause.
294 -------------------------------
295 -- Adjust_Esize_For_Alignment --
296 -------------------------------
301 begin
311 ------------------------------------
312 -- Build_And_Analyze_Renamed_Body --
313 ------------------------------------
315 procedure Build_And_Analyze_Renamed_Body
319 is
325 begin
326 -- If the renamed subprogram is intrinsic, there is no need for a
327 -- wrapper body: we set the alias that will be called and expanded which
328 -- completes the declaration. This transformation is only legal if the
329 -- renamed entity has already been elaborated.
331 -- Note that it is legal for a renaming_as_body to rename an intrinsic
332 -- subprogram, as long as the renaming occurs before the new entity
333 -- is frozen (RM 8.5.4 (5)).
337 then
339 else
345 and then
349 -- We can make the renaming entity intrinsic if the renamed function
350 -- has an interface name, or if it is one of the shift/rotate
351 -- operations known to the compiler.
353 and then
356 | Name_Rotate_Right
357 | Name_Shift_Left
358 | Name_Shift_Right
359 | Name_Shift_Right_Arithmetic)
360 then
365 else
372 else
381 ------------------------
382 -- Build_Renamed_Body --
383 ------------------------
385 function Build_Renamed_Body
388 is
390 -- We use for the source location of the renamed body, the location of
391 -- the spec entity. It might seem more natural to use the location of
392 -- the renaming declaration itself, but that would be wrong, since then
393 -- the body we create would look as though it was created far too late,
394 -- and this could cause problems with elaboration order analysis,
395 -- particularly in connection with instantiations.
410 -- If the renamed entity is a primitive operation given in prefix form,
411 -- the prefix is the target object and it has to be added as the first
412 -- actual in the generated call.
414 begin
415 -- Determine the entity being renamed, which is the target of the call
416 -- statement. If the name is an explicit dereference, this is a renaming
417 -- of a subprogram type rather than a subprogram. The name itself is
418 -- fully analyzed.
429 else
436 else
442 -- If the renamed entity is a predefined operator, retain full name
443 -- to ensure its visibility.
447 then
449 else
453 else
456 and then
459 then
461 -- Retrieve the target object, to be added as a first actual
462 -- in the call.
467 else
471 -- Original name may have been overloaded, but is fully resolved now
482 -- For simple renamings, subsequent calls can be expanded directly as
483 -- calls to the renamed entity. The body must be generated in any case
484 -- for calls that may appear elsewhere. This is not done in the case
485 -- where the subprogram is an instantiation because the actual proper
486 -- body has not been built yet.
490 then
494 -- Check whether the return type is a limited view. If the subprogram
495 -- is already frozen the generated body may have a non-limited view
496 -- of the type, that must be used, because it is the one in the spec
497 -- of the renaming declaration.
501 then
502 declare
504 begin
506 Set_Result_Definition
512 -- The body generated for this renaming is an internal artifact, and
513 -- does not constitute a freeze point for the called entity.
520 declare
524 begin
525 -- The controlling formal may be an access parameter, or the
526 -- actual may be an access value, so adjust accordingly.
530 then
531 Actuals := New_List
536 then
537 Actuals :=
538 New_List (
542 else
550 else
559 -- If the renamed entity is an entry, inherit its profile. For other
560 -- renamings as bodies, both profiles must be subtype conformant, so it
561 -- is not necessary to replace the profile given in the declaration.
562 -- However, default values that are aggregates are rewritten when
563 -- partially analyzed, so we recover the original aggregate to insure
564 -- that subsequent conformity checking works. Similarly, if the default
565 -- expression was constant-folded, recover the original expression.
575 N_Access_Definition
576 then
584 then
595 -- If the renamed entity is a function, the generated body contains a
596 -- return statement. Otherwise, build a procedure call. If the entity is
597 -- an entry, subsequent analysis of the call will transform it into the
598 -- proper entry or protected operation call. If the renamed entity is
599 -- a character literal, return it directly.
605 then
606 Call_Node :=
608 Expression =>
614 Call_Node :=
619 Call_Node :=
622 else
623 Call_Node :=
629 -- Create entities for subprogram body and formals
642 -- In GNATprove, prefer to generate an expression function whenever
643 -- possible, to benefit from the more precise analysis in that case
644 -- (as if an implicit postcondition had been generated).
646 if GNATprove_Mode
648 then
649 Body_Node :=
653 else
654 Body_Node :=
658 Handled_Statement_Sequence =>
663 -- Link the body to the entity whose declaration it completes. If
664 -- the body is analyzed when the renamed entity is frozen, it may
665 -- be necessary to restore the proper scope (see package Exp_Ch13).
669 then
671 else
678 --------------------------
679 -- Check_Address_Clause --
680 --------------------------
691 begin
694 -- For a deferred constant, the initialization value is on full view
698 else
707 -- Has_Delayed_Freeze was set on E when the address clause was
708 -- analyzed, and must remain set because we want the address
709 -- clause to be elaborated only after any entity it references
710 -- has been elaborated.
713 -- If Rep_Clauses are to be ignored, remove address clause from
714 -- list attached to entity, because it may be illegal for gigi,
715 -- for example by breaking order of elaboration.
718 declare
721 begin
727 else
730 loop
740 -- And now remove the address clause
746 then
752 -- If a variable, or a non-imported constant, overlays a constant
753 -- object and has an initialization value, then the initialization
754 -- may end up writing into read-only memory. Detect the cases of
755 -- statically identical values and remove the initialization. In
756 -- the other cases, give a warning. We will give other warnings
757 -- later for the variable if it is assigned.
764 then
765 declare
769 begin
775 and then Compile_Time_Compare
779 then
784 and then Address_Clause_Overlay_Warnings
785 then
787 Error_Msg_NE
794 -- Remove side effects from initial expression, except in the case of
795 -- limited build-in-place calls and aggregates, which have their own
796 -- expansion elsewhere. This exception is necessary to avoid copying
797 -- limited objects.
801 then
802 -- Capture initialization value at point of declaration, and make
803 -- explicit assignment legal, because object may be a constant.
809 -- Move initialization to freeze actions, once the object has
810 -- been frozen and the address clause alignment check has been
811 -- performed.
820 -- If the object is tagged, check whether the tag must be
821 -- reassigned explicitly.
831 -----------------------------
832 -- Check_Compile_Time_Size --
833 -----------------------------
838 -- Sets the compile time known size in the RM_Size field of T, checking
839 -- for a size clause that was given which attempts to give a small size.
842 -- Recursive function that does all the work
845 -- If T is a constrained subtype, its size is not known if any of its
846 -- discriminant constraints is not static and it is not a null record.
847 -- The test is conservative and doesn't check that the components are
848 -- in fact constrained by non-static discriminant values. Could be made
849 -- more precise ???
851 --------------------
852 -- Set_Small_Size --
853 --------------------
856 begin
860 -- Check for bad size clause given
868 -- Set size if not set already. Do not set it to Uint_0, because in
869 -- some cases (notably array-of-record), the Component_Size is
870 -- No_Uint, which causes S to be Uint_0. Presumably the RM_Size and
871 -- Component_Size will eventually be set correctly by the back end.
878 ----------------
879 -- Size_Known --
880 ----------------
886 begin
890 -- Always True for elementary types, even generic formal elementary
891 -- types. We used to return False in the latter case, but the size
892 -- is known at compile time, even in the template, we just do not
893 -- know the exact size but that's not the point of this routine.
898 -- Array types
902 -- String literals always have known size, and we can set it
906 Set_Small_Size
909 else
910 -- The following is wrong, but does what previous versions
911 -- did. The Component_Size is unknown for the string in a
912 -- pragma Warnings.
918 -- Unconstrained types never have known at compile time size
923 -- Don't do any recursion on type with error posted, since we may
924 -- have a malformed type that leads us into a loop.
929 -- Otherwise if component size unknown, then array size unknown
935 -- Check for all indexes static, and also compute possible size
936 -- (in case it is not greater than System_Max_Integer_Size and
937 -- thus may be packable).
939 declare
946 begin
947 -- See comment in Set_Small_Size above
961 else
969 then
972 else
977 else
989 -- For non-generic private types, go to underlying type if present
994 then
995 -- Don't do any recursion on type with error posted, since we may
996 -- have a malformed type that leads us into a loop.
1000 else
1004 -- Record types
1008 -- A class-wide type is never considered to have a known size
1013 -- A subtype of a variant record must not have non-static
1014 -- discriminated components.
1018 then
1021 -- Don't do any recursion on type with error posted, since we may
1022 -- have a malformed type that leads us into a loop.
1028 -- Now look at the components of the record
1030 declare
1031 -- The following two variables are used to keep track of the
1032 -- size of packed records if we can tell the size of the packed
1033 -- record in the front end. Packed_Size_Known is True if so far
1034 -- we can figure out the size. It is initialized to True for a
1035 -- packed record, unless the record has either discriminants or
1036 -- independent components, or is a strict-alignment type, since
1037 -- it cannot be fully packed in this case.
1039 -- The reason we eliminate the discriminated case is that
1040 -- we don't know the way the back end lays out discriminated
1041 -- packed records. If Packed_Size_Known is True, then
1042 -- Packed_Size is the size in bits so far.
1051 -- Size in bits so far
1053 begin
1054 -- Test for variant part present
1060 N_Record_Definition
1062 and then
1063 Present (Variant_Part
1065 then
1066 -- If variant part is present, and type is unconstrained,
1067 -- then we must have defaulted discriminants, or a size
1068 -- clause must be present for the type, or else the size
1069 -- is definitely not known at compile time.
1072 and then
1075 then
1080 -- Loop through components
1086 -- We do not know the packed size if there is a component
1087 -- clause present (we possibly could, but this would only
1088 -- help in the case of a record with partial rep clauses.
1089 -- That's because in the case of full rep clauses, the
1090 -- size gets figured out anyway by a different circuit).
1096 -- We do not know the packed size for an independent
1097 -- component or if it is of a strict-alignment type,
1098 -- since packing does not touch these (RM 13.2(7)).
1103 then
1107 -- We need to identify a component that is an array where
1108 -- the index type is an enumeration type with non-standard
1109 -- representation, and some bound of the type depends on a
1110 -- discriminant.
1112 -- This is because gigi computes the size by doing a
1113 -- substitution of the appropriate discriminant value in
1114 -- the size expression for the base type, and gigi is not
1115 -- clever enough to evaluate the resulting expression (which
1116 -- involves a call to rep_to_pos) at compile time.
1118 -- It would be nice if gigi would either recognize that
1119 -- this expression can be computed at compile time, or
1120 -- alternatively figured out the size from the subtype
1121 -- directly, where all the information is at hand ???
1125 then
1126 declare
1134 begin
1141 then
1147 then
1152 then
1162 -- Clearly size of record is not known if the size of one of
1163 -- the components is not known.
1169 -- Accumulate packed size if possible
1173 -- We can deal with elementary types, small packed arrays
1174 -- if the representation is a modular type and also small
1175 -- record types as checked by Set_Small_Size.
1179 and then Present
1181 and then Is_Modular_Integer_Type
1184 then
1185 -- If RM_Size is known and static, then we can keep
1186 -- accumulating the packed size.
1192 -- If we have a field whose RM_Size is not known then
1193 -- we can't figure out the packed size here.
1195 else
1199 -- For other types we can't figure out the packed size
1201 else
1216 -- All other cases, size not known at compile time
1218 else
1223 -------------------------------------
1224 -- Static_Discriminated_Components --
1225 -------------------------------------
1227 function Static_Discriminated_Components
1229 is
1232 begin
1236 then
1250 -- Start of processing for Check_Compile_Time_Size
1252 begin
1256 -----------------------------------
1257 -- Check_Component_Storage_Order --
1258 -----------------------------------
1260 procedure Check_Component_Storage_Order
1265 is
1274 -- Set for the record case, True if Comp is aligned on byte boundaries
1275 -- (in which case it is allowed to have different storage order).
1278 -- Set True when the component is a nested composite, and it does not
1279 -- have the same scalar storage order as Encl_Type.
1281 begin
1282 -- Record case
1292 else
1293 -- If a component clause is present, check if the component starts
1294 -- and ends on byte boundaries. Otherwise conservatively assume it
1295 -- does so only in the case where the record is not packed.
1298 Comp_Byte_Aligned :=
1300 and then
1302 and then
1304 and then
1306 else
1313 -- Array case
1315 else
1322 -- Note: the Reverse_Storage_Order flag is set on the base type, but
1323 -- the attribute definition clause is attached to the first subtype.
1324 -- Also, if the base type is incomplete or private, go to full view
1325 -- if known
1337 Comp_ADC :=
1338 Get_Attribute_Definition_Clause
1342 -- Case of record or array component: check storage order compatibility.
1343 -- But, if the record has Complex_Representation, then it is treated as
1344 -- a scalar in the back end so the storage order is irrelevant.
1349 then
1350 Comp_SSO_Differs :=
1354 -- Parent and extension must have same storage order
1358 Error_Msg_N
1363 -- If component and composite SSO differs, check that component
1364 -- falls on byte boundaries and isn't bit packed.
1368 -- Component SSO differs from enclosing composite:
1370 -- Reject if composite is a bit-packed array, as it is rewritten
1371 -- into an array of scalars.
1374 Error_Msg_N
1378 -- Reject if not byte aligned
1381 and then not Comp_Byte_Aligned
1382 then
1384 Error_Msg_N
1387 else
1388 Error_Msg_N
1393 -- Warn if specified only for the outer composite
1396 Error_Msg_NE
1402 -- Enclosing type has explicit SSO: non-composite component must not
1403 -- be aliased.
1406 Error_Msg_N
1412 -----------------------------
1413 -- Check_Debug_Info_Needed --
1414 -----------------------------
1417 begin
1422 or else Debug_Generated_Code
1423 or else Debug_Flag_VV
1425 then
1430 -------------------------------
1431 -- Check_Expression_Function --
1432 -------------------------------
1436 -- Function to search for deferred constant
1438 -------------------
1439 -- Find_Constant --
1440 -------------------
1443 begin
1444 -- When a constant is initialized with the result of a dispatching
1445 -- call, the constant declaration is rewritten as a renaming of the
1446 -- displaced function result. This scenario is not a premature use of
1447 -- a constant even though the Has_Completion flag is not set.
1454 N_Object_Declaration
1459 then
1460 Error_Msg_NE
1468 then
1482 -- Local variables
1486 -- Start of processing for Check_Expression_Function
1488 begin
1491 -- The subprogram body created for the expression function is not
1492 -- itself a freeze point.
1497 then
1502 --------------------------------
1503 -- Check_Inherited_Conditions --
1504 --------------------------------
1506 procedure Check_Inherited_Conditions
1509 is
1517 function Build_DTW_Body
1523 -- Build the body of the dispatch table wrapper containing the given
1524 -- spec and declarations; the call to the wrapped subprogram includes
1525 -- the proper type conversion.
1528 -- Build the spec of the dispatch table wrapper
1530 procedure Build_Inherited_Condition_Pragmas
1533 -- Build corresponding pragmas for an operation whose ancestor has
1534 -- class-wide pre/postconditions. If the operation is inherited then
1535 -- Wrapper_Needed is returned True to force the creation of a wrapper
1536 -- for the inherited operation. If the ancestor is being overridden,
1537 -- the pragmas are constructed only to verify their legality, in case
1538 -- they contain calls to other primitives that may have been overridden.
1540 function Needs_Wrapper
1544 -- Checks whether the dispatch-table wrapper (DTW) for Subp must be
1545 -- built to evaluate the given class-wide condition.
1547 --------------------
1548 -- Build_DTW_Body --
1549 --------------------
1551 function Build_DTW_Body
1557 is
1565 begin
1566 -- Build parameter association for call to wrapped subprogram
1571 -- If the controlling argument is inherited, add conversion to
1572 -- parent type for the call.
1576 then
1581 else
1590 Call :=
1594 else
1595 Call :=
1597 Expression =>
1603 return
1607 Handled_Statement_Sequence =>
1614 --------------------
1615 -- Build_DTW_Spec --
1616 --------------------
1622 begin
1626 -- Clear the not-overriding indicator since the DTW wrapper overrides
1627 -- its wrapped subprogram; required because if present in the parent
1628 -- primitive, given that Build_Overriding_Spec inherits it, we report
1629 -- spurious errors.
1633 -- Add minimal decoration of fields
1640 -- The DTW wrapper is never a null procedure
1649 ---------------------------------------
1650 -- Build_Inherited_Condition_Pragmas --
1651 ---------------------------------------
1653 procedure Build_Inherited_Condition_Pragmas
1656 is
1663 begin
1670 -- For class-wide preconditions we just evaluate whether the wrapper
1671 -- is needed; there is no need to build the pragma since the check
1672 -- is performed on the caller side.
1676 then
1680 -- For class-wide postconditions we evaluate whether the wrapper is
1681 -- needed and we build the class-wide postcondition pragma to install
1682 -- it in the wrapper.
1686 then
1689 -- Update the class-wide postcondition
1692 Build_Class_Wide_Expression
1698 -- Install the updated class-wide postcondition in a copy of the
1699 -- pragma postcondition defined for the nearest ancestor.
1702 Pragma_Postcondition);
1705 declare
1708 begin
1711 Pragma_Postcondition);
1717 -- A_Post can be null here if the postcondition was inlined in the
1718 -- called subprogram.
1722 Rewrite
1724 Class_Post);
1730 -------------------
1731 -- Needs_Wrapper --
1732 -------------------
1734 function Needs_Wrapper
1738 is
1742 -- Check calls to overridden primitives
1744 --------------------
1745 -- Replace_Entity --
1746 --------------------
1751 begin
1754 and then
1756 and then
1759 then
1760 -- Determine whether entity has a renaming
1764 -- If the entity is an overridden primitive and we are not
1765 -- in GNATprove mode, we must build a wrapper for the current
1766 -- inherited operation. If the reference is the prefix of an
1767 -- attribute such as 'Result (or others ???) there is no need
1768 -- for a wrapper: the condition is just rewritten in terms of
1769 -- the inherited subprogram.
1775 and then not GNATprove_Mode
1776 then
1788 -- Start of processing for Needs_Wrapper
1790 begin
1801 -- Cache the list of interface operations inherited by R
1804 -- List containing identifiers of built wrappers. Used to defer building
1805 -- and analyzing their class-wide precondition subprograms.
1807 -- Start of processing for Check_Inherited_Conditions
1809 begin
1815 -- Map the overridden primitive to the overriding one
1819 then
1823 -- Force discarding previous mappings of its formals
1832 -- Perform validity checks on the inherited conditions of overriding
1833 -- operations, for conformance with LSP, and apply SPARK-specific
1834 -- restrictions on inherited conditions.
1843 then
1844 -- When the primitive is an LSP wrapper we climb to the parent
1845 -- primitive that has the inherited contract.
1849 then
1853 -- Check that overrider and overridden operations have
1854 -- the same strub mode.
1858 -- Analyze the contract items of the overridden operation, before
1859 -- they are rewritten as pragmas.
1863 -- In GNATprove mode this is where we can collect the inherited
1864 -- conditions, because we do not create the Check pragmas that
1865 -- normally convey the modified class-wide conditions on
1866 -- overriding operations.
1873 -- Go over operations inherited from interfaces and check
1874 -- them for strub mode compatibility as well.
1879 then
1880 declare
1886 begin
1887 -- Collect the interfaces only once. We haven't
1888 -- finished freezing yet, so we can't use the faster
1889 -- search from Sem_Disp.Covered_Interface_Primitives.
1909 then
1924 -- Now examine the inherited operations to check whether they require
1925 -- a wrapper to handle inherited conditions that call other primitives,
1926 -- so that LSP can be verified/enforced.
1935 -- Skip internal entities built for mapping interface primitives
1940 then
1943 -- When the primitive is an LSP wrapper we climb to the parent
1944 -- primitive that has the inherited contract.
1948 then
1952 -- Analyze the contract items of the parent operation, and
1953 -- determine whether a wrapper is needed. This is determined
1954 -- when the condition is rewritten in sem_prag, using the
1955 -- mapping between overridden and overriding operations built
1956 -- in the loop above.
1962 if Wrapper_Needed
1964 and then Expander_Active
1965 then
1966 -- Build the dispatch-table wrapper (DTW). The support for
1967 -- AI12-0195 relies on two kind of wrappers: one for indirect
1968 -- calls (also used for AI12-0220), and one for putting in the
1969 -- dispatch table:
1970 --
1971 -- 1) "indirect-call wrapper" (ICW) is needed anytime there are
1972 -- class-wide preconditions. Prim'Access will point directly
1973 -- at the ICW if any, or at the "pristine" body if Prim has
1974 -- no class-wide preconditions.
1975 --
1976 -- 2) "dispatch-table wrapper" (DTW) is needed anytime the class
1977 -- wide preconditions *or* the class-wide postconditions are
1978 -- affected by overriding.
1979 --
1980 -- The DTW holds a single statement that is a single call where
1981 -- the controlling actuals are conversions to the corresponding
1982 -- type in the parent primitive. If the primitive is a function
1983 -- the statement is a return statement with a call.
1985 declare
1996 begin
2002 -- The spec of the wrapper has been built using the source
2003 -- location of its parent primitive; we must update it now
2004 -- (with the source location of the internal primitive built
2005 -- by Derive_Subprogram that will override this wrapper) to
2006 -- avoid inlining conflicts between internally built helpers
2007 -- for class-wide pre/postconditions of the parent and the
2008 -- helpers built for this wrapper.
2012 -- For inherited class-wide preconditions the DTW wrapper
2013 -- reuses the ICW of the parent (which checks the parent
2014 -- interpretation of the class-wide preconditions); the
2015 -- interpretation of the class-wide preconditions for the
2016 -- inherited subprogram is checked at the caller side.
2018 -- When the subprogram inherits class-wide postconditions
2019 -- the DTW also checks the interpretation of the class-wide
2020 -- postconditions for the inherited subprogram, and the body
2021 -- of the parent checks its interpretation of the parent for
2022 -- the class-wide postconditions.
2024 -- procedure Prim (F1 : T1; ...) is
2025 -- [ pragma Check (Postcondition, Expr); ]
2026 -- begin
2027 -- Par_Prim_ICW (Par_Type (F1), ...);
2028 -- end;
2031 DTW_Body :=
2038 -- For subprograms that only inherit class-wide postconditions
2039 -- the DTW wrapper calls the parent primitive (which on its
2040 -- body checks the interpretation of the class-wide post-
2041 -- conditions for the parent subprogram), and the DTW checks
2042 -- the interpretation of the class-wide postconditions for the
2043 -- inherited subprogram.
2045 -- procedure Prim (F1 : T1; ...) is
2046 -- pragma Check (Postcondition, Expr);
2047 -- begin
2048 -- Par_Prim (Par_Type (F1), ...);
2049 -- end;
2051 else
2052 DTW_Body :=
2060 -- Insert the declaration of the wrapper before the freezing
2061 -- node of the record type declaration to ensure that it will
2062 -- override the internal primitive built by Derive_Subprogram.
2067 else
2072 -- The analyis of DTW_Decl has removed Prim from its scope
2073 -- chain and added DTW_Id at the end of the scope chain. Move
2074 -- DTW_Id to its correct place in the scope chain: the analysis
2075 -- of the wrapper declaration has just added DTW_Id at the end
2076 -- of the list of entities of its scope. However, given that
2077 -- this wrapper overrides Prim, we must move DTW_Id to the
2078 -- original place of Prim in its scope chain. This is required
2079 -- for wrappers of private type primitives to ensure their
2080 -- correct visibility since wrappers are built when the full
2081 -- tagged type declaration is frozen (in the private part of
2082 -- the package) but they may override primitives defined in the
2083 -- public part of the package.
2085 declare
2088 begin
2090 pragma Assert
2095 -- Remove DTW_Id from the end of the doubly-linked list of
2096 -- entities of this scope; no need to handle removing it
2097 -- from the beginning of the chain since such case can never
2098 -- occur for this entity.
2103 -- Place DTW_Id back in the original place of its wrapped
2104 -- primitive in the list of entities of this scope.
2110 -- Insert the body of the wrapper in the freeze actions of
2111 -- its record type declaration to ensure that it is placed
2112 -- in the scope of its declaration but not too early to cause
2113 -- premature freezing of other entities.
2118 -- Ensure correct decoration
2124 -- Inherit dispatch table slot
2129 -- Register the wrapper in the dispatch table
2131 if Late_Overriding
2133 then
2138 -- Defer building helpers and ICW for the DTW. Required to
2139 -- ensure uniqueness in their names because when building
2140 -- these wrappers for overlapped subprograms their homonym
2141 -- number is not definite until all these dispatch table
2142 -- wrappers of tagged type R have been analyzed.
2153 -- Build and analyze deferred class-wide precondition subprograms of
2154 -- built wrappers.
2157 declare
2164 begin
2178 -- If the DTW was built for a late-overriding primitive
2179 -- its body must be analyzed now (since the tagged type
2180 -- is already frozen).
2183 Body_N :=
2192 ----------------------------
2193 -- Check_Strict_Alignment --
2194 ----------------------------
2199 begin
2200 -- Bit-packed array types do not require strict alignment, even if they
2201 -- are by-reference types, because they are accessed in a special way.
2209 -- ??? AI12-001: Any component of a packed type that contains an
2210 -- aliased part must be aligned according to the alignment of its
2211 -- subtype (RM 13.2(7)). This means that the following test:
2213 -- if Has_Aliased_Components (E) then
2214 -- Set_Strict_Alignment (E);
2215 -- end if;
2217 -- should be implemented here. Unfortunately it would break Florist,
2218 -- which has the bad habit of overaligning all the types it declares
2219 -- on 32-bit platforms. Other legacy codebases could also be affected
2220 -- because this check has historically been missing in GNAT.
2228 then
2238 -------------------------
2239 -- Check_Unsigned_Type --
2240 -------------------------
2247 begin
2252 -- Do not attempt to analyze case where range was in error
2258 -- The situation that is nontrivial is something like:
2260 -- subtype x1 is integer range -10 .. +10;
2261 -- subtype x2 is x1 range 0 .. V1;
2262 -- subtype x3 is x2 range V2 .. V3;
2263 -- subtype x4 is x3 range V4 .. V5;
2265 -- where Vn are variables. Here the base type is signed, but we still
2266 -- know that x4 is unsigned because of the lower bound of x2.
2268 -- The only way to deal with this is to look up the ancestor chain
2271 loop
2285 else
2288 -- If no ancestor had a static lower bound, go to base type
2292 -- Note: the reason we still check for a compile time known
2293 -- value for the base type is that at least in the case of
2294 -- generic formals, we can have bounds that fail this test,
2295 -- and there may be other cases in error situations.
2307 then
2317 -----------------------------------------------
2318 -- Explode_Initialization_Compound_Statement --
2319 -----------------------------------------------
2324 begin
2327 then
2330 -- Note that we rewrite Init_Stmts into a NULL statement, rather than
2331 -- just removing it, because Freeze_All may rely on this particular
2332 -- Node_Id still being present in the enclosing list to know where to
2333 -- stop freezing.
2341 ----------------
2342 -- Freeze_All --
2343 ----------------
2345 -- Note: the easy coding for this procedure would be to just build a
2346 -- single list of freeze nodes and then insert them and analyze them
2347 -- all at once. This won't work, because the analysis of earlier freeze
2348 -- nodes may recursively freeze types which would otherwise appear later
2349 -- on in the freeze list. So we must analyze and expand the freeze nodes
2350 -- as they are generated.
2354 -- This is the internal recursive routine that does freezing of entities
2355 -- (but NOT the analysis of default expressions, which should not be
2356 -- recursive, we don't want to analyze those till we are sure that ALL
2357 -- the types are frozen).
2359 --------------------
2360 -- Freeze_All_Ent --
2361 --------------------
2368 -- If freeze nodes are present, insert and analyze, and reset cursor
2369 -- for next insertion.
2371 -------------------
2372 -- Process_Flist --
2373 -------------------
2377 begin
2384 else
2390 -- Start of processing for Freeze_All_Ent
2392 begin
2396 -- If the entity is an inner package which is not a package
2397 -- renaming, then its entities must be frozen at this point. Note
2398 -- that such entities do NOT get frozen at the end of the nested
2399 -- package itself (only library packages freeze).
2401 -- Same is true for task declarations, where anonymous records
2402 -- created for entry parameters must be frozen.
2408 then
2419 then
2426 N_Single_Task_Declaration | N_Task_Type_Declaration
2427 then
2430 End_Scope;
2432 -- For a derived tagged type, we must ensure that all the
2433 -- primitive operations of the parent have been frozen, so that
2434 -- their addresses will be in the parent's dispatch table at the
2435 -- point it is inherited.
2441 then
2442 declare
2449 begin
2456 then
2458 Process_Flist;
2468 Process_Flist;
2470 -- If already frozen, and there are delayed aspects, this is where
2471 -- we do the visibility check for these aspects (see Sem_Ch13 spec
2472 -- for a description of how we handle aspect visibility).
2475 declare
2478 begin
2484 then
2493 -- If an incomplete type is still not frozen, this may be a
2494 -- premature freezing because of a body declaration that follows.
2495 -- Indicate where the freezing took place. Freezing will happen
2496 -- if the body comes from source, but not if it is internally
2497 -- generated, for example as the body of a type invariant.
2499 -- If the freezing is caused by the end of the current declarative
2500 -- part, it is a Taft Amendment type, and there is no error.
2504 then
2505 declare
2508 begin
2509 -- The presence of a body freezes all entities previously
2510 -- declared in the current list of declarations, but this
2511 -- does not apply if the body does not come from source.
2512 -- A type invariant is transformed into a subprogram body
2513 -- which is placed at the end of the private part of the
2514 -- current package, but this body does not freeze incomplete
2515 -- types that may be declared in this private part.
2519 | N_Package_Body
2520 | N_Protected_Body
2521 | N_Subprogram_Body
2522 | N_Task_Body
2523 | N_Body_Stub
2524 and then
2526 then
2528 Error_Msg_NE
2539 -- Local variables
2545 -- Start of processing for Freeze_All
2547 begin
2550 -- Now that all types are frozen, we can deal with default expressions
2551 -- that require us to build a default expression functions. This is the
2552 -- point at which such functions are constructed (after all types that
2553 -- might be used in such expressions have been frozen).
2555 -- For subprograms that are renaming_as_body, we create the wrapper
2556 -- bodies as needed.
2558 -- We also add finalization chains to access types whose designated
2559 -- types are controlled. This is normally done when freezing the type,
2560 -- but this misses recursive type definitions where the later members
2561 -- of the recursion introduce controlled components.
2563 -- Loop through entities
2572 -- Check subprogram renamings for the same strub-mode.
2573 -- Avoid rechecking dispatching operations, that's taken
2574 -- care of in Check_Inherited_Conditions, that covers
2575 -- inherited interface operations.
2580 then
2590 else
2596 and then
2598 N_Subprogram_Renaming_Declaration
2599 then
2600 Build_And_Analyze_Renamed_Body
2605 -- Freeze the default expressions of entries, entry families, and
2606 -- protected subprograms.
2613 then
2621 -- Historical note: We used to create a finalization master for an
2622 -- access type whose designated type is not controlled, but contains
2623 -- private controlled compoments. This form of postprocessing is no
2624 -- longer needed because the finalization master is now created when
2625 -- the access type is frozen (see Exp_Ch3.Freeze_Type).
2631 -----------------------
2632 -- Freeze_And_Append --
2633 -----------------------
2635 procedure Freeze_And_Append
2639 is
2640 -- Freezing an Expression_Function does not freeze its profile:
2641 -- the formals will have been frozen otherwise before the E_F
2642 -- can be called.
2645 Freeze_Entity
2647 begin
2651 else
2657 -------------------
2658 -- Freeze_Before --
2659 -------------------
2661 procedure Freeze_Before
2665 is
2666 -- Freeze T, then insert the generated Freeze nodes before the node N.
2667 -- Flag Freeze_Profile is used when T is an overloadable entity, and
2668 -- indicates whether its profile should be frozen at the same time.
2674 begin
2681 -- If the entity is a type declared in an inner package, it may be
2682 -- frozen by an outer declaration before the package itself is
2683 -- frozen. Install the package scope to analyze the freeze nodes,
2684 -- which may include generated subprograms such as predicate
2685 -- functions, etc.
2694 else
2700 -------------------
2701 -- Freeze_Entity --
2702 -------------------
2704 -- WARNING: This routine manages Ghost regions. Return statements must be
2705 -- replaced by gotos which jump to the end of the routine and restore the
2706 -- Ghost mode.
2708 function Freeze_Entity
2712 is
2717 -- Save the Ghost-related attributes to restore on exit
2726 -- List of freezing actions, left at No_List if none
2729 -- A local temporary used to test if freezing is necessary for E, since
2730 -- its value can be set to something other than E in certain cases. For
2731 -- example, E cannot be used directly in cases such as when it is an
2732 -- Itype defined within a record - since it is the location of record
2733 -- which matters.
2736 -- Add freeze action Fnod to list Result
2739 -- If Loc is a freeze_entity that appears after the last declaration
2740 -- in the scope, inhibit error messages on late completion.
2743 -- Check that an Access or Unchecked_Access attribute with a prefix
2744 -- which is the current instance type can only be applied when the type
2745 -- is limited.
2747 procedure Check_No_Parts_Violations
2750 Aspect_No_Controlled_Parts | Aspect_No_Task_Parts;
2751 -- Check that Typ does not violate the semantics of the specified
2752 -- Aspect_No_Parts (No_Controlled_Parts or No_Task_Parts) when it is
2753 -- specified on Typ or one of its ancestors.
2756 -- Give a warning for pragma Convention with language C or C++ applied
2757 -- to a discriminated record type. This is suppressed for the unchecked
2758 -- union case, since the whole point in this case is interface C. We
2759 -- also do not generate this within instantiations, since we will have
2760 -- generated a message on the template.
2763 -- Give warning for modulus of 8, 16, 32, 64 or 128 given as an explicit
2764 -- integer literal without an explicit corresponding size clause. The
2765 -- caller has checked that Utype is a modular integer type.
2768 -- Freeze array type, including freezing index and component types
2771 -- Perform checks and generate freeze node if needed for a constant or
2772 -- variable declared by an object declaration.
2775 -- Create Freeze_Generic_Entity nodes for types declared in a generic
2776 -- package. Recurse on inner generic packages.
2779 -- Freeze formals and return type of subprogram. If some type in the
2780 -- profile is incomplete and we are in an instance, freezing of the
2781 -- entity will take place elsewhere, and the function returns False.
2784 -- Freeze record type, including freezing component types, and freezing
2785 -- primitive operations if this is a tagged type.
2788 -- Determine whether an arbitrary entity is subject to Boolean aspect
2789 -- Import and its value is specified as True.
2791 procedure Inherit_Freeze_Node
2794 -- Set type Typ's freeze node to refer to Fnode. This routine ensures
2795 -- that any attributes attached to Typ's original node are preserved.
2798 -- If E is an entity for an imported subprogram with pre/post-conditions
2799 -- then this procedure will create a wrapper to ensure that proper run-
2800 -- time checking of the pre/postconditions. See body for details.
2802 -------------------
2803 -- Add_To_Result --
2804 -------------------
2807 begin
2811 ----------------------------
2812 -- After_Last_Declaration --
2813 ----------------------------
2818 begin
2824 else
2828 else
2833 ----------------------------
2834 -- Check_Current_Instance --
2835 ----------------------------
2840 -- Determine whether Typ is compatible with the rules for aliased
2841 -- views of types as defined in RM 3.10 in the various dialects.
2844 -- Process routine to apply check to given node
2846 -----------------------------
2847 -- Is_Aliased_View_Of_Type --
2848 -----------------------------
2853 begin
2854 -- Common case
2858 then
2861 -- The following paragraphs describe what a legal aliased view of
2862 -- a type is in the various dialects of Ada.
2864 -- Ada 95
2866 -- The current instance of a limited type, and a formal parameter
2867 -- or generic formal object of a tagged type.
2869 -- Ada 95 limited type
2870 -- * Type with reserved word "limited"
2871 -- * A protected or task type
2872 -- * A composite type with limited component
2877 -- Ada 2005
2879 -- The current instance of a limited tagged type, a protected
2880 -- type, a task type, or a type that has the reserved word
2881 -- "limited" in its full definition ... a formal parameter or
2882 -- generic formal object of a tagged type.
2884 -- Ada 2005 limited type
2885 -- * Type with reserved word "limited", "synchronized", "task"
2886 -- or "protected"
2887 -- * A composite type with limited component
2888 -- * A derived type whose parent is a non-interface limited type
2891 return
2893 or else
2898 -- Ada 2012 and beyond
2900 -- The current instance of an immutably limited type ... a formal
2901 -- parameter or generic formal object of a tagged type.
2903 -- Ada 2012 limited type
2904 -- * Type with reserved word "limited", "synchronized", "task"
2905 -- or "protected"
2906 -- * A composite type with limited component
2907 -- * A derived type whose parent is a non-interface limited type
2908 -- * An incomplete view
2910 -- Ada 2012 immutably limited type
2911 -- * Explicitly limited record type
2912 -- * Record extension with "limited" present
2913 -- * Non-formal limited private type that is either tagged
2914 -- or has at least one access discriminant with a default
2915 -- expression
2916 -- * Task type, protected type or synchronized interface
2917 -- * Type derived from immutably limited type
2919 else
2920 return
2926 -------------
2927 -- Process --
2928 -------------
2931 begin
2938 then
2940 Error_Msg_N
2943 else
2944 Error_Msg_N
2951 else
2962 -- Local variables
2967 -- Start of processing for Check_Current_Instance
2969 begin
2975 -------------------------------
2976 -- Check_No_Parts_Violations --
2977 -------------------------------
2979 procedure Check_No_Parts_Violations
2981 is
2983 function Find_Aspect_No_Parts
2985 -- Search for Aspect_No_Parts on a given type. When
2986 -- the aspect is not explicity specified Empty is returned.
2988 function Get_Aspect_No_Parts_Value
2990 -- Obtain the value for the Aspect_No_Parts on a given
2991 -- type. When the aspect is not explicitly specified Empty is
2992 -- returned.
2994 function Has_Aspect_No_Parts
2996 -- Predicate function which identifies whether No_Parts
2997 -- is explicitly specified on a given type.
2999 -------------------------------------
3000 -- Find_Aspect_No_Parts --
3001 -------------------------------------
3003 function Find_Aspect_No_Parts
3005 is
3012 begin
3014 -- Examine Typ's associated node, when present, since aspect
3015 -- specifications do not get transferred when nodes get rewritten.
3017 -- For example, this can happen in the expansion of array types
3022 = N_Full_Type_Declaration
3023 then
3024 Aspect_Spec :=
3025 Find_Aspect
3031 -- Examine aspects specifications on private type declarations
3033 -- Should Find_Aspect be improved to handle this case ???
3037 and then Present
3038 (Aspect_Specifications
3039 (Declaration_Node
3041 then
3042 Curr_Aspect_Spec :=
3043 First
3044 (Aspect_Specifications
3045 (Declaration_Node
3048 -- Search through aspects present on the private type
3052 = Aspect_No_Parts
3053 then
3063 -- When errors are posted on the aspect return Empty
3072 ------------------------------------------
3073 -- Get_Aspect_No_Parts_Value --
3074 ------------------------------------------
3076 function Get_Aspect_No_Parts_Value
3078 is
3081 begin
3083 -- Return the value of the aspect when present
3087 -- No expression is the same as True
3093 -- Assume its expression has already been constant folded into
3094 -- a Boolean value and return its value.
3099 -- Otherwise, the aspect is not specified - so return Empty
3104 ------------------------------------
3105 -- Has_Aspect_No_Parts --
3106 ------------------------------------
3108 function Has_Aspect_No_Parts
3112 -- Generic instances
3114 -------------------------------------------
3115 -- Get_Generic_Formal_Types_In_Hierarchy --
3116 -------------------------------------------
3118 function Get_Generic_Formal_Types_In_Hierarchy
3120 -- Return a list of all types within a given type's hierarchy which
3121 -- are generic formals.
3123 ----------------------------------------
3124 -- Get_Types_With_Aspect_In_Hierarchy --
3125 ----------------------------------------
3127 function Get_Types_With_Aspect_In_Hierarchy
3128 is new Collect_Types_In_Hierarchy
3130 -- Returns a list of all types within a given type's hierarchy which
3131 -- have the Aspect_No_Parts specified.
3133 -- Local declarations
3145 -- Start of processing for Check_No_Parts_Violations
3147 begin
3148 -- Nothing to check if the type is elementary or artificial
3156 -- Nothing to check if there are no types with No_Parts specified
3162 -- Set name for all errors below
3166 -- Obtain the aspect value for No_Parts for comparison
3168 Aspect_Value :=
3169 Get_Aspect_No_Parts_Value
3172 -- When the value is True and there are controlled/task parts or the
3173 -- type itself is controlled/task, trigger the appropriate error.
3178 then
3179 Error_Msg_N
3185 Error_Msg_N
3187 Error_Msg_N
3192 else
3197 -- Move through Types_With_Aspect - checking that the value specified
3198 -- for their corresponding Aspect_No_Parts do not override each
3199 -- other.
3203 Curr_Value :=
3206 -- Compare the aspect value against the current type
3209 Error_Msg_NE
3218 -- Issue an error if the aspect applies to a type declared inside a
3219 -- generic body and if said type derives from or has a component
3220 -- of ageneric formal type - since those are considered to have
3221 -- controlled/task parts and have Aspect_No_Parts specified as
3222 -- False by default (RM H.4.1(4/5) is about the language-defined
3223 -- No_Controlled_Parts aspect, and we are using the same rules for
3224 -- No_Task_Parts).
3226 -- We do not check tagged types since deriving from a formal type
3227 -- within an enclosing generic unit is already illegal
3228 -- (RM 3.9.1 (4/2)).
3233 then
3235 Gen_Formals :=
3236 Get_Generic_Formal_Types_In_Hierarchy
3240 -- Climb scopes collecting generic bodies
3245 -- Generic package body
3249 then
3252 -- Generic subprogram body
3261 -- Warn about the improper use of Aspect_No_Parts on a type
3262 -- declaration deriving from or that has a component of a generic
3263 -- formal type within the formal type's corresponding generic
3264 -- body by moving through all formal types in Typ's hierarchy and
3265 -- checking if they are formals in any of the enclosing generic
3266 -- bodies.
3268 -- However, a special exception gets made for formal types which
3269 -- derive from a type which has Aspect_No_Parts True.
3271 -- For example:
3273 -- generic
3274 -- type Form is private;
3275 -- package G is
3276 -- type Type_A is new Form with No_Controlled_Parts; -- OK
3277 -- end;
3278 --
3279 -- package body G is
3280 -- type Type_B is new Form with No_Controlled_Parts; -- ERROR
3281 -- end;
3283 -- generic
3284 -- type Form is private;
3285 -- package G is
3286 -- type Type_A is record C : Form; end record
3287 -- with No_Controlled_Parts; -- OK
3288 -- end;
3289 --
3290 -- package body G is
3291 -- type Type_B is record C : Form; end record
3292 -- with No_Controlled_Parts; -- ERROR
3293 -- end;
3295 -- type Root is tagged null record with No_Controlled_Parts;
3296 --
3297 -- generic
3298 -- type Form is new Root with private;
3299 -- package G is
3300 -- type Type_A is record C : Form; end record
3301 -- with No_Controlled_Parts; -- OK
3302 -- end;
3303 --
3304 -- package body G is
3305 -- type Type_B is record C : Form; end record
3306 -- with No_Controlled_Parts; -- OK
3307 -- end;
3315 -- Obtain types in the formal type's hierarchy which have
3316 -- the aspect specified.
3318 Types_With_Aspect :=
3319 Get_Types_With_Aspect_In_Hierarchy
3322 -- We found a type declaration in a generic body where both
3323 -- Aspect_No_Parts is true and one of its ancestors is a
3324 -- generic formal type.
3329 -- Check that no ancestors of the formal type have
3330 -- Aspect_No_Parts True before issuing the error.
3333 or else
3334 Get_Aspect_No_Parts_Value
3337 then
3340 Error_Msg
3355 ---------------------------------
3356 -- Check_Suspicious_Convention --
3357 ---------------------------------
3360 begin
3365 or else
3368 and then not In_Instance
3370 then
3371 declare
3376 begin
3381 Error_Msg_N
3384 else
3385 Error_Msg_N
3390 Error_Msg_NE
3398 ------------------------------
3399 -- Check_Suspicious_Modulus --
3400 ------------------------------
3405 begin
3411 declare
3414 begin
3416 declare
3420 begin
3422 declare
3426 begin
3427 -- First case, modulus and size are the same. This
3428 -- happens if you have something like mod 32, with
3429 -- an explicit size of 32, this is for sure a case
3430 -- where the warning is given, since it is seems
3431 -- very unlikely that someone would want e.g. a
3432 -- five bit type stored in 32 bits. It is much
3433 -- more likely they wanted a 32-bit type.
3438 -- Second case, the modulus is 32 or 64 and no
3439 -- size clause is present. This is a less clear
3440 -- case for giving the warning, but in the case
3441 -- of 32/64 (5-bit or 6-bit types) these seem rare
3442 -- enough that it is a likely error (and in any
3443 -- case using 2**5 or 2**6 in these cases seems
3444 -- clearer. We don't include 8 or 16 here, simply
3445 -- because in practice 3-bit and 4-bit types are
3446 -- more common and too many false positives if
3447 -- we warn in these cases.
3451 then
3454 -- No warning needed
3456 else
3460 -- If we fall through, give warning
3463 Error_Msg_N
3465 Modulus);
3474 -----------------------
3475 -- Freeze_Array_Type --
3476 -----------------------
3484 -- Set true if any of the index types is an enumeration type with a
3485 -- non-standard representation.
3487 begin
3496 then
3503 -- Processing that is done only for base types
3507 -- Deal with default setting of reverse storage order
3511 -- Propagate flags for component type
3515 then
3523 -- The array type requires its own invariant procedure in order to
3524 -- verify the component invariant over all elements. In GNATprove
3525 -- mode, the component invariants are checked by other means. They
3526 -- should not be added to the array type invariant procedure, so
3527 -- that the procedure can be used to check the array type
3528 -- invariants if any.
3531 and then not GNATprove_Mode
3532 then
3536 -- Warn for pragma Pack overriding foreign convention
3540 then
3541 declare
3546 begin
3550 Error_Msg_N
3553 Error_Msg_N
3560 -- Check for Aliased or Atomic_Components or Full Access with
3561 -- unsuitable packing or explicit component size clause given.
3566 and then
3568 then
3572 -- Outputs error messages for incorrect CS clause or pragma
3573 -- Pack for aliased or full access components (T is either
3574 -- "aliased" or "atomic" or "volatile full access");
3576 -----------------
3577 -- Complain_CS --
3578 -----------------
3581 begin
3583 Clause :=
3584 Get_Attribute_Definition_Clause
3587 Error_Msg_N
3591 Error_Msg_N
3594 else
3595 Error_Msg_N
3602 -- Start of processing for Alias_Atomic_Check
3604 begin
3605 -- If object size of component type isn't known, we cannot
3606 -- be sure so we defer to the back end.
3611 -- Case where component size has no effect. First check for
3612 -- object size of component type multiple of the storage
3613 -- unit size.
3617 -- OK in both packing case and component size case if RM
3618 -- size is known and static and same as the object size.
3620 and then
3624 -- Or if we have an explicit component size clause and
3625 -- the component size and object size are equal.
3627 or else
3630 then
3638 then
3647 -- Check for Independent_Components/Independent with unsuitable
3648 -- packing or explicit component size clause given.
3651 and then
3653 then
3654 begin
3655 -- If object size of component type isn't known, we cannot
3656 -- be sure so we defer to the back end.
3661 -- Case where component size has no effect. First check for
3662 -- object size of component type multiple of the storage
3663 -- unit size.
3667 -- OK in both packing case and component size case if RM
3668 -- size is known and multiple of the storage unit size.
3670 and then
3674 -- Or if we have an explicit component size clause and
3675 -- the component size is larger than the object size.
3677 or else
3680 then
3683 else
3685 Clause :=
3686 Get_Attribute_Definition_Clause
3689 Error_Msg_N
3693 Error_Msg_N
3696 else
3697 Error_Msg_N
3706 -- If packing was requested or if the component size was
3707 -- set explicitly, then see if bit packing is required. This
3708 -- processing is only done for base types, since all of the
3709 -- representation aspects involved are type-related.
3711 -- This is not just an optimization, if we start processing the
3712 -- subtypes, they interfere with the settings on the base type
3713 -- (this is because Is_Packed has a slightly different meaning
3714 -- before and after freezing).
3716 declare
3720 begin
3724 then
3733 else
3736 -- We can set the component size if it is less than 16,
3737 -- rounding it up to the next storage unit size.
3743 else
3747 -- Set component size up to match alignment if it would
3748 -- otherwise be less than the alignment. This deals with
3749 -- cases of types whose alignment exceeds their size (the
3750 -- padded type cases).
3753 declare
3755 begin
3763 -- Case of component size that may result in bit packing
3766 declare
3772 Get_Attribute_Definition_Clause
3775 begin
3776 -- Warn if we have pack and component size so that the
3777 -- pack is ignored.
3779 -- Note: here we must check for the presence of a
3780 -- component size before checking for a Pack pragma to
3781 -- deal with the case where the array type is a derived
3782 -- type whose parent is currently private.
3786 and then Warn_On_Redundant_Constructs
3787 then
3789 Error_Msg_NE
3791 Error_Msg_N
3797 -- Set component size if not already set by a component
3798 -- size clause.
3804 -- Check for base type of 8, 16, 32 bits, where an
3805 -- unsigned subtype has a length one less than the
3806 -- base type (e.g. Natural subtype of Integer).
3808 -- In such cases, if a component size was not set
3809 -- explicitly, then generate a warning.
3816 then
3820 Error_Msg_N
3822 Pack_Pragma);
3823 Error_Msg_N
3825 Pack_Pragma);
3829 -- Bit packing is never needed for 8, 16, 32, 64 or 128
3833 -- If the Esize of the component is known and equal to
3834 -- the component size then even packing is not needed.
3838 then
3839 -- Here the array was requested to be packed, but
3840 -- the packing request had no effect whatsoever,
3841 -- so flag Is_Packed is reset.
3843 -- Note: semantically this means that we lose track
3844 -- of the fact that a derived type inherited pragma
3845 -- Pack that was non-effective, but that is fine.
3847 -- We regard a Pack pragma as a request to set a
3848 -- representation characteristic, and this request
3849 -- may be ignored.
3853 else
3860 -- Bit packing is not needed for multiples of the storage
3861 -- unit if the type is composite because the back end can
3862 -- byte pack composite types efficiently. That's not true
3863 -- for discrete types because every read would generate a
3864 -- lot of instructions, so we keep using the manipulation
3865 -- routines of the runtime for them.
3869 then
3874 -- In all other cases, bit packing is needed
3876 else
3885 -- Warn for case of atomic type
3891 then
3892 Error_Msg_NE
3907 -- Check for scalar storage order
3909 declare
3911 begin
3912 Check_Component_Storage_Order
3915 ADC => Get_Attribute_Definition_Clause
3917 Attribute_Scalar_Storage_Order),
3921 -- Processing that is done only for subtypes
3923 else
3924 -- Acquire alignment from base type. Known_Alignment of the base
3925 -- type is False for Wide_String, for example.
3929 then
3935 -- Specific checks for bit-packed arrays
3939 -- Check number of elements for bit-packed arrays that come from
3940 -- source and have compile time known ranges. The bit-packed
3941 -- arrays circuitry does not support arrays with more than
3942 -- Integer'Last + 1 elements, and when this restriction is
3943 -- violated, causes incorrect data access.
3945 -- For the case where this is not compile time known, a run-time
3946 -- check should be generated???
3949 declare
3955 begin
3961 -- Never generate an error if any index is of a generic
3962 -- type. We will check this in instances.
3969 Ilen :=
3975 -- No attempt is made to check number of elements if not
3976 -- compile time known.
3989 then
3990 Error_Msg_N
3997 -- Check size
4000 declare
4004 begin
4005 -- It is not clear if it is possible to have no size clause
4006 -- at this stage, but it is not worth worrying about. Post
4007 -- error on the entity name in the size clause if present,
4008 -- else on the type entity itself.
4012 else
4019 -- If any of the index types was an enumeration type with a non-
4020 -- standard rep clause, then we indicate that the array type is
4021 -- always packed (even if it is not bit-packed).
4030 -- If the array is packed and bit-packed or packed to eliminate holes
4031 -- in the non-contiguous enumeration index types, we must create the
4032 -- packed array type to be used to actually implement the type. This
4033 -- is only needed for real array types (not for string literal types,
4034 -- since they are present only for the front end).
4039 then
4043 -- Make sure that we have the necessary routines to implement the
4044 -- packing, and complain now if not. Note that we only test this
4045 -- for constrained array types.
4051 then
4052 declare
4056 begin
4059 then
4060 Error_Msg_CRT
4064 -- Cancel the packing
4074 -- Size information of packed array type is copied to the array
4075 -- type, since this is really the representation. But do not
4076 -- override explicit existing size values. If the ancestor subtype
4077 -- is constrained the Packed_Array_Impl_Type will be inherited
4078 -- from it, but the size may have been provided already, and
4079 -- must not be overridden either.
4082 and then
4085 then
4091 Copy_Alignment
4098 -- A Ghost type cannot have a component of protected or task type
4099 -- (SPARK RM 6.9(19)).
4102 Error_Msg_N
4104 Arr);
4108 -------------------------------
4109 -- Freeze_Object_Declaration --
4110 -------------------------------
4114 -- Check that the size of array type Typ can be computed without
4115 -- overflow, and generates a Storage_Error otherwise. This is only
4116 -- relevant for array types whose index has System_Max_Integer_Size
4117 -- bits, where wrap-around arithmetic might yield a meaningless value
4118 -- for the length of the array, or its corresponding attribute.
4121 -- Ensure that the initialization state of variable Var_Id subject
4122 -- to pragma Thread_Local_Storage agrees with the semantics of the
4123 -- pragma.
4125 function Has_Default_Initialization
4127 -- Determine whether object Obj_Id default initialized
4129 -------------------------------
4130 -- Check_Large_Modular_Array --
4131 -------------------------------
4137 begin
4138 -- Nothing to do when expansion is disabled because this routine
4139 -- generates a runtime check.
4144 -- Nothing to do for String literal subtypes because their index
4145 -- cannot be a modular type.
4150 -- Nothing to do for an imported object because the object will
4151 -- be created on the exporting side.
4156 -- Nothing to do for unconstrained array types. This case arises
4157 -- when the object declaration is illegal.
4165 -- To prevent arithmetic overflow with large values, we raise
4166 -- Storage_Error under the following guard:
4167 --
4168 -- (Arr'Last / 2 - Arr'First / 2) > (2 ** 30)
4169 --
4170 -- This takes care of the boundary case, but it is preferable to
4171 -- use a smaller limit, because even on 64-bit architectures an
4172 -- array of more than 2 ** 30 bytes is likely to raise
4173 -- Storage_Error.
4177 then
4180 Condition =>
4182 Left_Opnd =>
4184 Left_Opnd =>
4186 Left_Opnd =>
4188 Prefix =>
4191 Right_Opnd =>
4193 Right_Opnd =>
4195 Left_Opnd =>
4197 Prefix =>
4200 Right_Opnd =>
4202 Right_Opnd =>
4208 ---------------------------------------
4209 -- Check_Pragma_Thread_Local_Storage --
4210 ---------------------------------------
4213 function Has_Incompatible_Initialization
4215 -- Determine whether variable Var_Id with declaration Var_Decl is
4216 -- initialized with a value that violates the semantics of pragma
4217 -- Thread_Local_Storage.
4219 -------------------------------------
4220 -- Has_Incompatible_Initialization --
4221 -------------------------------------
4223 function Has_Incompatible_Initialization
4225 is
4228 begin
4229 -- The variable is default-initialized. This directly violates
4230 -- the semantics of the pragma.
4235 -- The variable has explicit initialization. In this case only
4236 -- a handful of values satisfy the semantics of the pragma.
4240 then
4241 -- "null" is a legal form of initialization
4246 -- A static expression is a legal form of initialization
4251 -- A static aggregate is a legal form of initialization
4255 then
4258 -- All other initialization expressions violate the semantic
4259 -- of the pragma.
4261 else
4265 -- The variable lacks any kind of initialization, which agrees
4266 -- with the semantics of the pragma.
4268 else
4273 -- Local declarations
4277 -- Start of processing for Check_Pragma_Thread_Local_Storage
4279 begin
4280 -- A variable whose initialization is suppressed lacks any kind of
4281 -- initialization.
4286 -- The variable has default initialization, or is explicitly
4287 -- initialized to a value other than null, static expression,
4288 -- or a static aggregate.
4291 Error_Msg_NE
4294 Error_Msg_NE
4300 --------------------------------
4301 -- Has_Default_Initialization --
4302 --------------------------------
4304 function Has_Default_Initialization
4306 is
4310 begin
4311 return
4315 and then
4319 or else
4324 -- Local variables
4329 -- Start of processing for Freeze_Object_Declaration
4331 begin
4332 -- Abstract type allowed only for C++ imported variables or constants
4334 -- Note: we inhibit this check for objects that do not come from
4335 -- source because there is at least one case (the expansion of
4336 -- x'Class'Input where x is abstract) where we legitimately
4337 -- generate an abstract object.
4342 then
4351 Error_Msg_N -- CODEFIX
4356 -- For object created by object declaration, perform required
4357 -- categorization (preelaborate and pure) checks. Defer these
4358 -- checks to freeze time since pragma Import inhibits default
4359 -- initialization and thus pragma Import affects these checks.
4363 -- If there is an address clause, check that it is valid and if need
4364 -- be move initialization to the freeze node.
4368 -- Similar processing is needed for aspects that may affect object
4369 -- layout, like Address, if there is an initialization expression.
4370 -- We don't do this if there is a pragma Linker_Section, because it
4371 -- would prevent the back end from statically initializing the
4372 -- object; we don't want elaboration code in that case.
4375 and then Expander_Active
4379 then
4380 declare
4384 begin
4385 -- Capture initialization value at point of declaration, and
4386 -- make explicit assignment legal, because object may be a
4387 -- constant.
4392 -- Move initialization to freeze actions
4400 -- Set_Is_Frozen (E, False);
4404 -- Reset Is_True_Constant for non-constant aliased object. We
4405 -- consider that the fact that a non-constant object is aliased may
4406 -- indicate that some funny business is going on, e.g. an aliased
4407 -- object is passed by reference to a procedure which captures the
4408 -- address of the object, which is later used to assign a new value,
4409 -- even though the compiler thinks that it is not modified. Such
4410 -- code is highly dubious, but we choose to make it "work" for
4411 -- non-constant aliased objects.
4413 -- Note that we used to do this for all aliased objects, whether or
4414 -- not constant, but this caused anomalies down the line because we
4415 -- ended up with static objects that were not Is_True_Constant. Not
4416 -- resetting Is_True_Constant for (aliased) constant objects ensures
4417 -- that this anomaly never occurs.
4419 -- However, we don't do that for internal entities. We figure that if
4420 -- we deliberately set Is_True_Constant for an internal entity, e.g.
4421 -- a dispatch table entry, then we mean it.
4426 then
4430 -- If the object needs any kind of default initialization, an error
4431 -- must be issued if No_Default_Initialization applies. The check
4432 -- doesn't apply to imported objects, which are not ever default
4433 -- initialized, and is why the check is deferred until freezing, at
4434 -- which point we know if Import applies. Deferred constants are also
4435 -- exempted from this test because their completion is explicit, or
4436 -- through an import pragma.
4442 Check_Restriction
4446 -- Ensure that a variable subject to pragma Thread_Local_Storage
4447 --
4448 -- * Lacks default initialization, or
4449 --
4450 -- * The initialization expression is either "null", a static
4451 -- constant, or a compile-time known aggregate.
4457 -- For imported objects, set Is_Public unless there is also an
4458 -- address clause, which means that there is no external symbol
4459 -- needed for the Import (Is_Public may still be set for other
4460 -- unrelated reasons). Note that we delayed this processing
4461 -- till freeze time so that we can be sure not to set the flag
4462 -- if there is an address clause. If there is such a clause,
4463 -- then the only purpose of the Import pragma is to suppress
4464 -- implicit initialization.
4470 -- For source objects that are not Imported and are library level, if
4471 -- no linker section pragma was given inherit the appropriate linker
4472 -- section from the corresponding type.
4478 then
4482 -- For convention C objects of an enumeration type, warn if the size
4483 -- is not integer size and no explicit size given. Skip warning for
4484 -- Boolean and Character, and assume programmer expects 8-bit sizes
4485 -- for these cases.
4488 or else
4495 then
4497 Error_Msg_N
4502 -- Declaring too big an array in disabled ghost code is OK
4509 -----------------------------
4510 -- Freeze_Generic_Entities --
4511 -----------------------------
4518 begin
4537 --------------------
4538 -- Freeze_Profile --
4539 --------------------
4546 begin
4547 -- Loop through formals
4553 -- AI05-0151: incomplete types can appear in a profile. By the
4554 -- time the entity is frozen, the full view must be available,
4555 -- unless it is a limited view.
4560 then
4567 then
4576 then
4577 -- If the type of a formal is incomplete, subprogram is being
4578 -- frozen prematurely. Within an instance (but not within a
4579 -- wrapper package) this is an artifact of our need to regard
4580 -- the end of an instantiation as a freeze point. Otherwise it
4581 -- is a definite error.
4589 Error_Msg_NE
4591 N,
4592 F_Type);
4596 -- Check suspicious parameter for C function. These tests apply
4597 -- only to exported/imported subprograms.
4599 if Warn_On_Export_Import
4607 then
4608 -- Qualify mention of formals with subprogram name
4612 -- Check suspicious use of fat C pointer, but do not emit
4613 -- a warning on an access to subprogram when unnesting is
4614 -- active.
4621 then
4622 Error_Msg_N
4625 -- Check suspicious return of boolean
4631 then
4632 Error_Msg_N
4634 Error_Msg_N
4638 -- Check suspicious tagged type
4641 or else
4645 then
4646 Error_Msg_N
4650 -- Check wrong convention subprogram pointer
4654 then
4655 Error_Msg_N
4659 Error_Msg_NE
4664 -- Turn off name qualification after message output
4669 -- Check for unconstrained array in exported foreign convention
4670 -- case.
4676 and then Warn_On_Export_Import
4677 then
4680 -- If this is an inherited operation, place the warning on
4681 -- the derived type declaration, rather than on the original
4682 -- subprogram.
4685 then
4691 else
4698 Warn_Node);
4711 -- Case of function: similar checks on return type
4715 -- Freeze return type
4719 -- AI05-0151: the return type may have been incomplete at the
4720 -- point of declaration. Replace it with the full view, unless the
4721 -- current type is a limited view. In that case the full view is
4722 -- in a different unit, and gigi finds the non-limited view after
4723 -- the other unit is elaborated.
4728 then
4737 -- Check suspicious return type for C function
4739 if Warn_On_Export_Import
4743 then
4744 -- Check suspicious return of fat C pointer
4751 then
4752 Error_Msg_N
4754 E);
4756 -- Check suspicious return of boolean
4763 then
4764 declare
4767 begin
4768 Error_Msg_NE
4770 Error_Msg_NE
4775 -- Check suspicious return tagged type
4779 and then
4780 Is_Tagged_Type
4785 then
4789 -- Check return of wrong convention subprogram pointer
4795 then
4799 Error_Msg_NE
4805 -- Give warning for suspicious return of a result of an
4806 -- unconstrained array type in a foreign convention function.
4810 -- We are looking for a return of unconstrained array
4815 -- Exclude imported routines, the warning does not belong on
4816 -- the import, but rather on the routine definition.
4820 -- Check that general warning is enabled, and that it is not
4821 -- suppressed for this particular case.
4823 and then Warn_On_Export_Import
4826 then
4827 Error_Msg_N
4833 -- Check suspicious use of Import in pure unit (cases where the RM
4834 -- allows calls to be omitted).
4838 -- It might be suspicious if the compilation unit has the Pure
4839 -- aspect/pragma.
4843 -- The RM allows omission of calls only in the case of
4844 -- library-level subprograms (see RM-10.2.1(18)).
4848 -- Ignore internally generated entity. This happens in some cases
4849 -- of subprograms in specs, where we generate an implied body.
4853 -- Assume run-time knows what it is doing
4855 and then not GNAT_Mode
4857 -- Assume explicit Pure_Function means import is pure
4861 -- Don't need warning in relaxed semantics mode
4863 and then not Relaxed_RM_Semantics
4865 -- Assume convention Intrinsic is OK, since this is specialized.
4866 -- This deals with the DEC unit current_exception.ads
4870 -- Assume that ASM interface knows what it is doing
4873 then
4874 Error_Msg_N
4876 Error_Msg_NE
4884 ------------------------
4885 -- Freeze_Record_Type --
4886 ------------------------
4898 -- Set True if we find at least one component which is aliased. This
4899 -- is used to prevent Implicit_Packing of the record, since packing
4900 -- cannot modify the size of alignment of an aliased component.
4903 -- True if all components are of a type whose underlying type is
4904 -- elementary.
4907 -- True if all components have a known RM_Size
4910 -- True if all components have an RM_Size that is a multiple of the
4911 -- storage unit.
4914 -- Accumulates total Esize values of all elementary components. Used
4915 -- for processing of Implicit_Packing.
4918 -- Set True if we find at least one component with a component
4919 -- clause (used to warn about useless Bit_Order pragmas, and also
4920 -- to detect cases where Implicit_Packing may have an effect).
4923 -- Accumulates total RM_Size values of all sized components. Used
4924 -- for processing of Implicit_Packing.
4927 -- Accumulates total RM_Size values of all sized components, rounded
4928 -- individually to a multiple of the storage unit.
4931 -- Scalar_Storage_Order attribute definition clause for the record
4934 -- Set True if we find at least one component whose type has a
4935 -- Scalar_Storage_Order attribute definition clause.
4938 -- Set True if we find at least one component with no component
4939 -- clause (used to warn about useless Pack pragmas).
4942 -- If the component subtype is an access to a constrained subtype of
4943 -- an already frozen type, make the subtype frozen as well. It might
4944 -- otherwise be frozen in the wrong scope, and a freeze node on
4945 -- subtype has no effect. Similarly, if the component subtype is a
4946 -- regular (not protected) access to subprogram, set the anonymous
4947 -- subprogram type to frozen as well, to prevent an out-of-scope
4948 -- freeze node at some eventual point of call. Protected operations
4949 -- are handled elsewhere.
4952 -- Make sure that all types mentioned in Discrete_Choices of the
4953 -- variants referenceed by the Variant_Part VP are frozen. This is
4954 -- a recursive routine to deal with nested variants.
4956 -----------------
4957 -- Check_Itype --
4958 -----------------
4963 begin
4966 then
4969 -- In addition, add an Itype_Reference to ensure that the
4970 -- access subtype is elaborated early enough. This cannot be
4971 -- done if the subtype may depend on discriminants.
4976 then
4984 then
4990 ------------------------------------
4991 -- Freeze_Choices_In_Variant_Part --
4992 ------------------------------------
5001 begin
5002 -- Loop through variants
5007 -- Loop through choices, checking that all types are frozen
5013 then
5020 -- Check for nested variant part to process
5034 -- Start of processing for Freeze_Record_Type
5036 begin
5037 -- Freeze components and embedded subtypes
5046 -- Handle the component and discriminant case
5049 declare
5052 begin
5053 -- Freezing a record type freezes the type of each of its
5054 -- components. However, if the type of the component is
5055 -- part of this record, we do not want or need a separate
5056 -- Freeze_Node. Note that Is_Itype is wrong because that's
5057 -- also set in private type cases. We also can't check for
5058 -- the Scope being exactly Rec because of private types and
5059 -- record extensions.
5064 then
5070 -- Warn for pragma Pack overriding foreign convention
5075 -- Don't warn for aliased components, since override
5076 -- cannot happen in that case.
5079 then
5080 declare
5085 begin
5089 Error_Msg_N
5091 PP);
5093 Error_Msg_NE
5100 -- Check for error of component clause given for variable
5101 -- sized type. We have to delay this test till this point,
5102 -- since the component type has to be frozen for us to know
5103 -- if it is variable length.
5108 -- We omit this test in a generic context, it will be
5109 -- applied at instantiation time.
5114 -- Also omit this test in CodePeer mode, since we do not
5115 -- have sufficient info on size and rep clauses.
5120 -- Do the check
5122 elsif not
5123 Size_Known_At_Compile_Time
5125 then
5126 Error_Msg_N
5131 else
5135 -- Case of component requires byte alignment
5139 -- Set the enclosing record to also require byte align
5143 -- Check for component clause that is inconsistent with
5144 -- the required byte boundary alignment.
5149 then
5150 Error_Msg_N
5158 -- Gather data for possible Implicit_Packing later. Note that at
5159 -- this stage we might be dealing with a real component, or with
5160 -- an implicit subtype declaration.
5163 declare
5168 begin
5169 Sized_Component_Total_RM_Size :=
5172 Sized_Component_Total_Round_RM_Size :=
5173 Sized_Component_Total_Round_RM_Size +
5178 then
5179 Elem_Component_Total_Esize :=
5181 else
5189 else
5193 -- If the component is an Itype with Delayed_Freeze and is either
5194 -- a record or array subtype and its base type has not yet been
5195 -- frozen, we must remove this from the entity list of this record
5196 -- and put it on the entity list of the scope of its base type.
5197 -- Note that we know that this is not the type of a component
5198 -- since we cleared Has_Delayed_Freeze for it in the previous
5199 -- loop. Thus this must be the Designated_Type of an access type,
5200 -- which is the type of a component.
5208 then
5209 declare
5213 begin
5214 -- We have a difficult case to handle here. Suppose Rec is
5215 -- subtype being defined in a subprogram that's created as
5216 -- part of the freezing of Rec'Base. In that case, we know
5217 -- that Comp'Base must have already been frozen by the time
5218 -- we get to elaborate this because Gigi doesn't elaborate
5219 -- any bodies until it has elaborated all of the declarative
5220 -- part. But Is_Frozen will not be set at this point because
5221 -- we are processing code in lexical order.
5223 -- We detect this case by going up the Scope chain of Rec
5224 -- and seeing if we have a subprogram scope before reaching
5225 -- the top of the scope chain or that of Comp'Base. If we
5226 -- do, then mark that Comp'Base will actually be frozen. If
5227 -- so, we merely undelay it.
5244 else
5247 else
5251 -- Insert in entity list of scope of base type (which
5252 -- must be an enclosing scope, because still unfrozen).
5258 -- If the component is an access type with an allocator as default
5259 -- value, the designated type will be frozen by the corresponding
5260 -- expression in init_proc. In order to place the freeze node for
5261 -- the designated type before that for the current record type,
5262 -- freeze it now.
5264 -- Same process if the component is an array of access types,
5265 -- initialized with an aggregate. If the designated type is
5266 -- private, it cannot contain allocators, and it is premature
5267 -- to freeze the type, so we check for this as well.
5271 and then
5273 in N_Component_Declaration | N_Discriminant_Specification
5275 then
5276 declare
5280 begin
5283 -- If component is pointer to a class-wide type, freeze
5284 -- the specific type in the expression being allocated.
5285 -- The expression may be a subtype indication, in which
5286 -- case freeze the subtype mark.
5289 then
5291 Freeze_And_Append
5295 then
5296 Freeze_And_Append
5302 else
5303 Freeze_And_Append
5310 then
5313 -- Freeze the designated type when initializing a component with
5314 -- an aggregate in case the aggregate contains allocators.
5316 -- type T is ...;
5317 -- type T_Ptr is access all T;
5318 -- type T_Array is array ... of T_Ptr;
5320 -- type Rec is record
5321 -- Comp : T_Array := (others => ...);
5322 -- end record;
5326 then
5327 declare
5330 Designated_Type
5333 begin
5334 -- The only case when this sort of freezing is not done is
5335 -- when the designated type is class-wide and the root type
5336 -- is the record owning the component. This scenario results
5337 -- in a circularity because the class-wide type requires
5338 -- primitives that have not been created yet as the root
5339 -- type is in the process of being frozen.
5341 -- type Rec is tagged;
5342 -- type Rec_Ptr is access all Rec'Class;
5343 -- type Rec_Array is array ... of Rec_Ptr;
5345 -- type Rec is record
5346 -- Comp : Rec_Array := (others => ...);
5347 -- end record;
5351 then
5359 then
5369 SSO_ADC :=
5370 Get_Attribute_Definition_Clause
5373 -- If the record type has Complex_Representation, then it is treated
5374 -- as a scalar in the back end so the storage order is irrelevant.
5378 Error_Msg_N
5380 SSO_ADC);
5383 else
5384 -- Deal with default setting of reverse storage order
5388 -- Check consistent attribute setting on component types
5390 declare
5392 begin
5395 Check_Component_Storage_Order
5405 -- Now deal with reverse storage order/bit order issues
5409 -- Check compatibility of Scalar_Storage_Order with Bit_Order,
5410 -- if the former is specified.
5414 -- Note: report error on Rec, not on SSO_ADC, as ADC may
5415 -- apply to some ancestor type.
5418 Error_Msg_N
5423 -- Warn if there is a Scalar_Storage_Order attribute definition
5424 -- clause but no component clause, no component that itself has
5425 -- such an attribute definition, and no pragma Pack.
5428 or else
5429 SSO_ADC_Component
5430 or else
5432 then
5433 Error_Msg_N
5440 -- Deal with Bit_Order aspect
5448 then
5449 -- Warn if clause has no effect when no component clause is
5450 -- present, but suppress warning if the Bit_Order is required
5451 -- due to the presence of a Scalar_Storage_Order attribute.
5453 Error_Msg_N
5455 Error_Msg_N
5458 -- Here is where we do the processing to adjust component clauses
5459 -- for reversed bit order, when not using reverse SSO. If an error
5460 -- has been reported on Rec already (such as SSO incompatible with
5461 -- bit order), don't bother adjusting as this may generate extra
5462 -- noise.
5467 then
5470 -- Case where we have both an explicit Bit_Order and the same
5471 -- Scalar_Storage_Order: leave record untouched, the back-end
5472 -- will take care of required layout conversions.
5474 else
5480 -- Check for useless pragma Pack when all components placed. We only
5481 -- do this check for record types, not subtypes, since a subtype may
5482 -- have all its components placed, and it still makes perfectly good
5483 -- sense to pack other subtypes or the parent type. We do not give
5484 -- this warning if Optimize_Alignment is set to Space, since the
5485 -- pragma Pack does have an effect in this case (it always resets
5486 -- the alignment to one).
5490 and then not Unplaced_Component
5492 then
5493 -- Reset packed status. Probably not necessary, but we do it so
5494 -- that there is no chance of the back end doing something strange
5495 -- with this redundant indication of packing.
5499 -- Give warning if redundant constructs warnings on
5502 Error_Msg_N -- CODEFIX
5508 -- If this is the record corresponding to a remote type, freeze the
5509 -- remote type here since that is what we are semantically freezing.
5510 -- This prevents the freeze node for that type in an inner scope.
5517 -- Check for controlled components, unchecked unions, and type
5518 -- invariants.
5523 -- Do not set Has_Controlled_Component on a class-wide
5524 -- equivalent type. See Make_CW_Equivalent_Type.
5527 and then
5529 or else
5532 or else
5534 and then
5536 and then
5537 Has_Controlled_Component
5539 then
5547 -- The record type requires its own invariant procedure in
5548 -- order to verify the invariant of each individual component.
5549 -- Do not consider internal components such as _parent because
5550 -- parent class-wide invariants are always inherited.
5551 -- In GNATprove mode, the component invariants are checked by
5552 -- other means. They should not be added to the record type
5553 -- invariant procedure, so that the procedure can be used to
5554 -- check the recordy type invariants if any.
5558 and then not GNATprove_Mode
5559 then
5563 -- Scan component declaration for likely misuses of current
5564 -- instance, either in a constraint or a default expression.
5574 -- Enforce the restriction that access attributes with a current
5575 -- instance prefix can only apply to limited types. This comment
5576 -- is floating here, but does not seem to belong here???
5578 -- Set component alignment if not otherwise already set
5582 -- For first subtypes, check if there are any fixed-point fields with
5583 -- component clauses, where we must check the size. This is not done
5584 -- till the freeze point since for fixed-point types, we do not know
5585 -- the size until the type is frozen. Similar processing applies to
5586 -- bit-packed arrays.
5594 then
5595 Check_Size
5599 Junk);
5606 -- See if Size is too small as is (and implicit packing might help)
5610 -- No implicit packing if even one component is explicitly placed
5612 and then not Placed_Component
5614 -- Or even one component is aliased
5616 and then not Aliased_Component
5618 -- Must have size clause and all sized components
5621 and then All_Sized_Components
5623 -- Do not try implicit packing on records with discriminants, too
5624 -- complicated, especially in the variant record case.
5628 -- We want to implicitly pack if the specified size of the record
5629 -- is less than the sum of the object sizes (no point in packing
5630 -- if this is not the case), if we can compute it, i.e. if we have
5631 -- only elementary components. Otherwise, we have at least one
5632 -- composite component and we want to implicitly pack only if bit
5633 -- packing is required for it, as we are sure in this case that
5634 -- the back end cannot do the expected layout without packing.
5636 and then
5637 ((All_Elem_Components
5639 or else
5641 and then not All_Storage_Unit_Components
5644 -- And the total RM size cannot be greater than the specified size
5645 -- since otherwise packing will not get us where we have to be.
5649 -- Never do implicit packing in CodePeer or SPARK modes since
5650 -- we don't do any packing in these modes, since this generates
5651 -- over-complex code that confuses static analysis, and in
5652 -- general, neither CodePeer not GNATprove care about the
5653 -- internal representation of objects.
5656 then
5657 -- If implicit packing enabled, do it
5662 -- Otherwise flag the size clause
5664 else
5665 declare
5667 begin
5668 Error_Msg_NE -- CODEFIX
5670 Error_Msg_N -- CODEFIX
5677 -- The following checks are relevant only when SPARK_Mode is on as
5678 -- they are not standard Ada legality rules.
5682 -- A discriminated type cannot be effectively volatile
5683 -- (SPARK RM 7.1.3(5)).
5690 -- A non-effectively volatile record type cannot contain
5691 -- effectively volatile components (SPARK RM 7.1.3(6)).
5693 else
5698 then
5700 Error_Msg_N
5709 -- A type which does not yield a synchronized object cannot have
5710 -- a component that yields a synchronized object (SPARK RM 9.5).
5717 then
5719 Error_Msg_N
5728 -- A Ghost type cannot have a component of protected or task type
5729 -- (SPARK RM 6.9(19)).
5736 then
5738 Error_Msg_N
5740 Comp);
5748 -- Make sure that if we have an iterator aspect, then we have
5749 -- either Constant_Indexing or Variable_Indexing.
5751 declare
5754 begin
5763 or else
5765 then
5767 else
5768 Error_Msg_N
5770 Iterator_Aspect);
5775 -- All done if not a full record definition
5781 -- Finally we need to check the variant part to make sure that
5782 -- all types within choices are properly frozen as part of the
5783 -- freezing of the record type.
5790 begin
5791 -- Find component list
5803 then
5808 -- Case of variant part present
5814 -- Note: we used to call Check_Choices here, but it is too early,
5815 -- since predicated subtypes are frozen here, but their freezing
5816 -- actions are in Analyze_Freeze_Entity, which has not been called
5817 -- yet for entities frozen within this procedure, so we moved that
5818 -- call to the Analyze_Freeze_Entity for the record type.
5822 -- Check that all the primitives of an interface type are abstract
5823 -- or null procedures.
5827 then
5828 declare
5832 begin
5839 -- Avoid reporting the error on inherited primitives
5842 then
5847 Error_Msg_N
5851 else
5852 Error_Msg_N
5863 -- For a derived tagged type, check whether inherited primitives
5864 -- might require a wrapper to handle class-wide conditions.
5871 -------------------------------
5872 -- Has_Boolean_Aspect_Import --
5873 -------------------------------
5880 begin
5886 -- The value of aspect Import is True when the expression is
5887 -- either missing or it is explicitly set to True.
5893 then
5904 -------------------------
5905 -- Inherit_Freeze_Node --
5906 -------------------------
5908 procedure Inherit_Freeze_Node
5911 is
5914 begin
5918 -- The input type had an existing node. Propagate relevant attributes
5919 -- from the old freeze node to the inherited freeze node.
5921 -- ??? if both freeze nodes have attributes, would they differ?
5925 -- Attribute Access_Types_To_Process
5929 then
5934 -- Attribute Actions
5940 -- Attribute First_Subtype_Link
5944 then
5948 -- Attribute TSS_Elist
5952 then
5958 ------------------------------
5959 -- Wrap_Imported_Subprogram --
5960 ------------------------------
5962 -- The issue here is that our normal approach of checking preconditions
5963 -- and postconditions does not work for imported procedures, since we
5964 -- are not generating code for the body. To get around this we create
5965 -- a wrapper, as shown by the following example:
5967 -- procedure K (A : Integer);
5968 -- pragma Import (C, K);
5970 -- The spec is rewritten by removing the effects of pragma Import, but
5971 -- leaving the convention unchanged, as though the source had said:
5973 -- procedure K (A : Integer);
5974 -- pragma Convention (C, K);
5976 -- and we create a body, added to the entity K freeze actions, which
5977 -- looks like:
5979 -- procedure K (A : Integer) is
5980 -- procedure K (A : Integer);
5981 -- pragma Import (C, K);
5982 -- begin
5983 -- K (A);
5984 -- end K;
5986 -- Now the contract applies in the normal way to the outer procedure,
5987 -- and the inner procedure has no contracts, so there is no problem
5988 -- in just calling it to get the original effect.
5990 -- In the case of a function, we create an appropriate return statement
5991 -- for the subprogram body that calls the inner procedure.
5995 -- Obtain a copy of the Import_Pragma which belongs to subprogram E
5997 ------------------------
5998 -- Copy_Import_Pragma --
5999 ------------------------
6003 -- The subprogram should have an import pragma, otherwise it does
6004 -- need a wrapper.
6009 -- Save all semantic fields of the pragma
6018 begin
6019 -- Reset all semantic fields. This avoids a potential infinite
6020 -- loop when the pragma comes from an aspect as the duplication
6021 -- will copy the aspect, then copy the corresponding pragma and
6022 -- so on.
6031 -- Restore the original semantic fields
6041 -- Local variables
6052 -- Start of processing for Wrap_Imported_Subprogram
6054 begin
6055 -- Nothing to do if not imported
6060 -- Test enabling conditions for wrapping
6065 and then not GNATprove_Mode
6066 then
6067 -- Here we do the wrap
6069 -- Note on calls to Copy_Separate_Tree. The trees we are copying
6070 -- here are fully analyzed, but we definitely want fully syntactic
6071 -- unanalyzed trees in the body we construct, so that the analysis
6072 -- generates the right visibility, and that is exactly what the
6073 -- calls to Copy_Separate_Tree give us.
6077 -- Fix up spec so it is no longer imported and has convention Ada
6085 -- Grab the subprogram declaration and specification
6089 -- Build parameter list that we need
6098 -- Build the call
6100 -- An imported function whose result type is anonymous access
6101 -- creates a new anonymous access type when it is relocated into
6102 -- the declarations of the body generated below. As a result, the
6103 -- accessibility level of these two anonymous access types may not
6104 -- be compatible even though they are essentially the same type.
6105 -- Use an unchecked type conversion to reconcile this case. Note
6106 -- that the conversion is safe because in the named access type
6107 -- case, both the body and imported function utilize the same
6108 -- type.
6111 Stmt :=
6113 Expression =>
6119 else
6120 Stmt :=
6126 -- Now build the body
6128 Bod :=
6130 Specification =>
6135 Prag),
6136 Handled_Statement_Sequence =>
6141 -- Append the body to freeze result
6146 -- Case of imported subprogram that does not get wrapped
6148 else
6149 -- Set Is_Public. All imported entities need an external symbol
6150 -- created for them since they are always referenced from another
6151 -- object file. Note this used to be set when we set Is_Imported
6152 -- back in Sem_Prag, but now we delay it to this point, since we
6153 -- don't want to set this flag if we wrap an imported subprogram.
6159 -- Start of processing for Freeze_Entity
6161 begin
6162 -- The entity being frozen may be subject to pragma Ghost. Set the mode
6163 -- now to ensure that any nodes generated during freezing are properly
6164 -- flagged as Ghost.
6168 -- We are going to test for various reasons why this entity need not be
6169 -- frozen here, but in the case of an Itype that's defined within a
6170 -- record, that test actually applies to the record.
6177 then
6181 -- Do not freeze if already frozen since we only need one freeze node
6187 -- Do not freeze if we are preanalyzing without freezing
6197 -- It is improper to freeze an external entity within a generic because
6198 -- its freeze node will appear in a non-valid context. The entity will
6199 -- be frozen in the proper scope after the current generic is analyzed.
6200 -- However, aspects must be analyzed because they may be queried later
6201 -- within the generic itself, and the corresponding pragma or attribute
6202 -- definition has not been analyzed yet. After this, indicate that the
6203 -- entity has no further delayed aspects, to prevent a later aspect
6204 -- analysis out of the scope of the generic.
6215 -- AI05-0213: A formal incomplete type does not freeze the actual. In
6216 -- the instance, the same applies to the subtype renaming the actual.
6222 then
6226 -- Formal subprograms are never frozen
6232 -- Generic types are never frozen as they lack delayed semantic checks
6238 -- Do not freeze a global entity within an inner scope created during
6239 -- expansion. A call to subprogram E within some internal procedure
6240 -- (a stream attribute for example) might require freezing E, but the
6241 -- freeze node must appear in the same declarative part as E itself.
6242 -- The two-pass elaboration mechanism in gigi guarantees that E will
6243 -- be frozen before the inner call is elaborated. We exclude constants
6244 -- from this test, because deferred constants may be frozen early, and
6245 -- must be diagnosed (e.g. in the case of a deferred constant being used
6246 -- in a default expression). If the enclosing subprogram comes from
6247 -- source, or is a generic instance, then the freeze point is the one
6248 -- mandated by the language, and we freeze the entity. A subprogram that
6249 -- is a child unit body that acts as a spec does not have a spec that
6250 -- comes from source, but can only come from source.
6255 then
6256 -- Here we deal with the special case of the expansion of
6257 -- postconditions. Previously this was handled by the loop below,
6258 -- since these postcondition checks got isolated to a separate,
6259 -- internally generated, subprogram. Now, however, the postcondition
6260 -- checks get contained within their corresponding subprogram
6261 -- directly.
6268 -- Now, verify the placement of the pragma is within an expanded
6269 -- subprogram which contains postcondition expansion - detected
6270 -- through the presence of the "Wrapped_Statements" field.
6275 then
6279 -- Otherwise, loop through scopes checking if an enclosing scope
6280 -- comes from source or is a generic. Note that, for the purpose
6281 -- of this test, we need to consider that the internally generated
6282 -- subprogram described above comes from source too if the original
6283 -- subprogram itself does.
6285 declare
6288 begin
6297 then
6299 else
6309 -- Similarly, an inlined instance body may make reference to global
6310 -- entities, but these references cannot be the proper freezing point
6311 -- for them, and in the absence of inlining freezing will take place in
6312 -- their own scope. Normally instance bodies are analyzed after the
6313 -- enclosing compilation, and everything has been frozen at the proper
6314 -- place, but with front-end inlining an instance body is compiled
6315 -- before the end of the enclosing scope, and as a result out-of-order
6316 -- freezing must be prevented.
6318 elsif Front_End_Inlining
6319 and then In_Instance_Body
6321 then
6322 declare
6325 begin
6330 else
6342 -- Add checks to detect proper initialization of scalars that may appear
6343 -- as subprogram parameters.
6349 -- Deal with delayed aspect specifications. The analysis of the aspect
6350 -- is required to be delayed to the freeze point, thus we analyze the
6351 -- pragma or attribute definition clause in the tree at this point. We
6352 -- also analyze the aspect specification node at the freeze point when
6353 -- the aspect doesn't correspond to pragma/attribute definition clause.
6354 -- In addition, a derived type may have inherited aspects that were
6355 -- delayed in the parent, so these must also be captured now.
6357 -- For a record type, we deal with the delayed aspect specifications on
6358 -- components first, which is consistent with the non-delayed case and
6359 -- makes it possible to have a single processing to detect conflicts.
6362 declare
6366 -- Set True if the record type E has been pushed on the scope
6367 -- stack. Needed for the analysis of delayed aspects specified
6368 -- to the components of Rec.
6370 begin
6378 -- The visibility to the discriminants must be restored
6379 -- in order to properly analyze the aspects.
6392 -- Pop the scope if Rec scope has been pushed on the scope stack
6393 -- during the delayed aspect analysis process.
6400 Pop_Scope;
6409 -- Here to freeze the entity
6413 -- Case of entity being frozen is other than a type
6417 -- If entity is exported or imported and does not have an external
6418 -- name, now is the time to provide the appropriate default name.
6419 -- Skip this if the entity is stubbed, since we don't need a name
6420 -- for any stubbed routine. For the case on intrinsics, if no
6421 -- external name is specified, then calls will be handled in
6422 -- Exp_Intr.Expand_Intrinsic_Call, and no name is needed. If an
6423 -- external name is provided, then Expand_Intrinsic_Call leaves
6424 -- calls in place for expansion by GIGI.
6430 then
6431 Set_Encoded_Interface_Name
6435 -- Subprogram case
6439 -- Check for needing to wrap imported subprogram
6443 -- Freeze all parameter types and the return type (RM 13.14(14)).
6444 -- However skip this for internal subprograms. This is also where
6445 -- any extra formal parameters are created since we now know
6446 -- whether the subprogram will use a foreign convention.
6448 -- In Ada 2012, freezing a subprogram does not always freeze the
6449 -- corresponding profile (see AI05-019). An attribute reference
6450 -- is not a freezing point of the profile. Similarly, we do not
6451 -- freeze the profile of primitives of a library-level tagged type
6452 -- when we are building its dispatch table. Flag Do_Freeze_Profile
6453 -- indicates whether the profile should be frozen now.
6455 -- This processing doesn't apply to internal entities (see below)
6463 -- Must freeze its parent first if it is a derived subprogram
6469 -- We don't freeze internal subprograms, because we don't normally
6470 -- want addition of extra formals or mechanism setting to happen
6471 -- for those. However we do pass through predefined dispatching
6472 -- cases, since extra formals may be needed in some cases, such as
6473 -- for the stream 'Input function (build-in-place formals).
6477 then
6481 -- If warning on suspicious contracts then check for the case of
6482 -- a postcondition other than False for a No_Return subprogram.
6485 and then Warn_On_Suspicious_Contract
6487 then
6488 declare
6492 begin
6495 | Name_Postcondition
6496 | Name_Refined_Post
6497 then
6498 Exp :=
6499 Expression
6504 then
6505 Error_Msg_NE
6516 -- Here for other than a subprogram or type
6518 else
6519 -- If entity has a type declared in the current scope, and it is
6520 -- not a generic unit, then freeze it first.
6525 then
6528 -- For an object of an anonymous array type, aspects on the
6529 -- object declaration apply to the type itself. This is the
6530 -- case for Atomic_Components, Volatile_Components, and
6531 -- Independent_Components. In these cases analysis of the
6532 -- generated pragma will mark the anonymous types accordingly,
6533 -- and the object itself does not require a freeze node.
6539 then
6546 -- Special processing for objects created by object declaration;
6547 -- we protect the call to Declaration_Node against entities of
6548 -- expressions replaced by the frontend with an N_Raise_CE node.
6552 then
6556 -- Check that a constant which has a pragma Volatile[_Components]
6557 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
6559 -- Note: Atomic[_Components] also sets Volatile[_Components]
6565 then
6566 -- Make sure we actually have a pragma, and have not merely
6567 -- inherited the indication from elsewhere (e.g. an address
6568 -- clause, which is not good enough in RM terms).
6571 or else
6573 then
6574 Error_Msg_N
6579 or else
6581 then
6582 Error_Msg_N
6588 -- Static objects require special handling
6592 then
6596 -- Remaining step is to layout objects
6600 then
6604 -- For an object that does not have delayed freezing, and whose
6605 -- initialization actions have been captured in a compound
6606 -- statement, move them back now directly within the enclosing
6607 -- statement sequence.
6611 then
6615 -- Do not generate a freeze node for a generic unit
6623 -- Case of a type or subtype being frozen
6625 else
6626 -- Verify several SPARK legality rules related to Ghost types now
6627 -- that the type is frozen.
6631 -- We used to check here that a full type must have preelaborable
6632 -- initialization if it completes a private type specified with
6633 -- pragma Preelaborable_Initialization, but that missed cases where
6634 -- the types occur within a generic package, since the freezing
6635 -- that occurs within a containing scope generally skips traversal
6636 -- of a generic unit's declarations (those will be frozen within
6637 -- instances). This check was moved to Analyze_Package_Specification.
6639 -- The type may be defined in a generic unit. This can occur when
6640 -- freezing a generic function that returns the type (which is
6641 -- defined in a parent unit). It is clearly meaningless to freeze
6642 -- this type. However, if it is a subtype, its size may be determi-
6643 -- nable and used in subsequent checks, so might as well try to
6644 -- compute it.
6646 -- In Ada 2012, Freeze_Entities is also used in the front end to
6647 -- trigger the analysis of aspect expressions, so in this case we
6648 -- want to continue the freezing process.
6650 -- Is_Generic_Unit (Scope (E)) is dubious here, do we want instead
6651 -- In_Generic_Scope (E)???
6655 and then
6658 then
6664 -- Check for error of Type_Invariant'Class applied to an untagged
6665 -- type (check delayed to freeze time when full type is available).
6667 declare
6669 begin
6673 then
6674 Error_Msg_NE
6676 Error_Msg_N
6681 -- Deal with special cases of freezing for subtype
6685 -- Before we do anything else, a specific test for the case of a
6686 -- size given for an array where the array would need to be packed
6687 -- in order for the size to be honored, but is not. This is the
6688 -- case where implicit packing may apply. The reason we do this so
6689 -- early is that, if we have implicit packing, the layout of the
6690 -- base type is affected, so we must do this before we freeze the
6691 -- base type.
6693 -- We could do this processing only if implicit packing is enabled
6694 -- since in all other cases, the error would be caught by the back
6695 -- end. However, we choose to do the check even if we do not have
6696 -- implicit packing enabled, since this allows us to give a more
6697 -- useful error message (advising use of pragma Implicit_Packing
6698 -- or pragma Pack).
6701 declare
6714 -- Number of elements in array
6716 begin
6717 -- Check enabling conditions. These are straightforward
6718 -- except for the test for a limited composite type. This
6719 -- eliminates the rare case of a array of limited components
6720 -- where there are issues of whether or not we can go ahead
6721 -- and pack the array (since we can't freely pack and unpack
6722 -- arrays if they are limited).
6724 -- Note that we check the root type explicitly because the
6725 -- whole point is we are doing this test before we have had
6726 -- a chance to freeze the base type (and it is that freeze
6727 -- action that causes stuff to be inherited).
6729 -- The conditions on the size are identical to those used in
6730 -- Freeze_Array_Type to set the Is_Packed flag.
6748 then
6749 -- Compute number of elements in array
6756 and then
6758 then
6766 else
6773 -- What we are looking for here is the situation where
6774 -- the RM_Size given would be exactly right if there was
6775 -- a pragma Pack, resulting in the component size being
6776 -- the RM_Size of the component type.
6780 -- For implicit packing mode, just set the component
6781 -- size and Freeze_Array_Type will do the rest.
6786 -- Otherwise give an error message, except that if the
6787 -- specified Size is zero, there is no need for pragma
6788 -- Pack. Note that size zero is not considered
6789 -- Addressable.
6792 Error_Msg_NE
6794 Error_Msg_N -- CODEFIX
6805 -- If ancestor subtype present, freeze that first. Note that this
6806 -- will also get the base type frozen. Need RM reference ???
6813 -- No ancestor subtype present
6815 else
6816 -- See if we have a nearest ancestor that has a predicate.
6817 -- That catches the case of derived type with a predicate.
6818 -- Need RM reference here ???
6826 -- Freeze base type before freezing the entity (RM 13.14(15))
6833 -- A subtype inherits all the type-related representation aspects
6834 -- from its parents (RM 13.1(8)).
6842 -- For a derived type, freeze its parent type first (RM 13.14(15))
6847 -- A derived type inherits each type-related representation aspect
6848 -- of its parent type that was directly specified before the
6849 -- declaration of the derived type (RM 13.1(15)).
6858 -- Case of array type
6864 -- Check for incompatible size and alignment for array/record type
6866 if Warn_On_Size_Alignment
6871 -- If explicit Object_Size clause given assume that the programmer
6872 -- knows what he is doing, and expects the compiler behavior.
6876 -- It does not really make sense to warn for the minimum alignment
6877 -- since the programmer could not get rid of the warning.
6881 -- Check for size not a multiple of alignment
6884 then
6885 declare
6891 begin
6894 -- Give a warning
6898 Error_Msg_NE
6905 else
6907 Error_Msg_NE
6921 -- For a class-wide type, the corresponding specific type is
6922 -- frozen as well (RM 13.14(15))
6927 -- If the base type of the class-wide type is still incomplete,
6928 -- the class-wide remains unfrozen as well. This is legal when
6929 -- E is the formal of a primitive operation of some other type
6930 -- which is being frozen.
6937 -- The equivalent type associated with a class-wide subtype needs
6938 -- to be frozen to ensure that its layout is done.
6942 then
6946 -- Generate an itype reference for a library-level class-wide type
6947 -- at the freeze point. Otherwise the first explicit reference to
6948 -- the type may appear in an inner scope which will be rejected by
6949 -- the back-end.
6953 then
6954 declare
6957 begin
6960 -- From a gigi point of view, a class-wide subtype derives
6961 -- from its record equivalent type. As a result, the itype
6962 -- reference must appear after the freeze node of the
6963 -- equivalent type or gigi will reject the reference.
6967 then
6969 else
6975 -- For a record type or record subtype, freeze all component types
6976 -- (RM 13.14(15)). We test for E_Record_(sub)Type here, rather than
6977 -- using Is_Record_Type, because we don't want to attempt the freeze
6978 -- for the case of a private type with record extension (we will do
6979 -- that later when the full type is frozen).
6986 -- Report a warning if a discriminated record base type has a
6987 -- convention with language C or C++ applied to it. This check is
6988 -- done even within generic scopes (but not in instantiations),
6989 -- which is why we don't do it as part of Freeze_Record_Type.
6993 -- For a concurrent type, freeze corresponding record type. This does
6994 -- not correspond to any specific rule in the RM, but the record type
6995 -- is essentially part of the concurrent type. Also freeze all local
6996 -- entities. This includes record types created for entry parameter
6997 -- blocks and whatever local entities may appear in the private part.
7011 -- The guard on the presence of the Etype seems to be needed
7012 -- for some CodePeer (-gnatcC) cases, but not clear why???
7017 then
7028 -- Private types are required to point to the same freeze node as
7029 -- their corresponding full views. The freeze node itself has to
7030 -- point to the partial view of the entity (because from the partial
7031 -- view, we can retrieve the full view, but not the reverse).
7032 -- However, in order to freeze correctly, we need to freeze the full
7033 -- view. If we are freezing at the end of a scope (or within the
7034 -- scope) of the private type, the partial and full views will have
7035 -- been swapped, the full view appears first in the entity chain and
7036 -- the swapping mechanism ensures that the pointers are properly set
7037 -- (on scope exit).
7039 -- If we encounter the partial view before the full view (e.g. when
7040 -- freezing from another scope), we freeze the full view, and then
7041 -- set the pointers appropriately since we cannot rely on swapping to
7042 -- fix things up (subtypes in an outer scope might not get swapped).
7044 -- If the full view is itself private, the above requirements apply
7045 -- to the underlying full view instead of the full view. But there is
7046 -- no swapping mechanism for the underlying full view so we need to
7047 -- set the pointers appropriately in both cases.
7051 then
7052 -- The construction of the dispatch table associated with library
7053 -- level tagged types forces freezing of all the primitives of the
7054 -- type, which may cause premature freezing of the partial view.
7055 -- For example:
7057 -- package Pkg is
7058 -- type T is tagged private;
7059 -- type DT is new T with private;
7060 -- procedure Prim (X : in out T; Y : in out DT'Class);
7061 -- private
7062 -- type T is tagged null record;
7063 -- Obj : T;
7064 -- type DT is new T with null record;
7065 -- end;
7067 -- In this case the type will be frozen later by the usual
7068 -- mechanism: an object declaration, an instantiation, or the
7069 -- end of a declarative part.
7073 then
7077 -- Case of full view present
7081 -- If full view has already been frozen, then no further
7082 -- processing is required
7088 -- Otherwise freeze full view and patch the pointers so that
7089 -- the freeze node will elaborate both views in the back end.
7090 -- However, if full view is itself private, freeze underlying
7091 -- full view instead and patch the pointers so that the freeze
7092 -- node will elaborate the three views in the back end.
7094 else
7095 declare
7098 begin
7101 then
7109 then
7113 Inherit_Freeze_Node
7115 else
7126 else
7127 -- {Incomplete,Private}_Subtypes with Full_Views
7128 -- constrained by discriminants.
7139 -- AI95-117 requires that the convention of a partial view be
7140 -- the same as the convention of the full view. Note that this
7141 -- is a recognized breach of privacy, but it's essential for
7142 -- logical consistency of representation, and the lack of a
7143 -- rule in RM95 was an oversight.
7150 -- Size information is copied from the full view to the
7151 -- incomplete or private view for consistency.
7153 -- We skip this is the full view is not a type. This is very
7154 -- strange of course, and can only happen as a result of
7155 -- certain illegalities, such as a premature attempt to derive
7156 -- from an incomplete type.
7165 -- Case of underlying full view present
7169 then
7174 -- Patch the pointers so that the freeze node will elaborate
7175 -- both views in the back end.
7181 Inherit_Freeze_Node
7184 else
7194 -- Case of no full view present. If entity is subtype or derived,
7195 -- it is safe to freeze, correctness depends on the frozen status
7196 -- of parent. Otherwise it is either premature usage, or a Taft
7197 -- amendment type, so diagnosis is at the point of use and the
7198 -- type might be frozen later.
7201 declare
7204 begin
7205 -- However, if the base type is itself private and has no
7206 -- (underlying) full view either, wait until the full type
7207 -- declaration is seen and all the full views are created.
7214 then
7224 else
7230 -- For access subprogram, freeze types of all formals, the return
7231 -- type was already frozen, since it is the Etype of the function.
7232 -- Formal types can be tagged Taft amendment types, but otherwise
7233 -- they cannot be incomplete.
7240 then
7244 -- AI05-151: Incomplete types are allowed in access to
7245 -- subprogram specifications.
7248 Error_Msg_NE
7259 -- For access to a protected subprogram, freeze the equivalent type
7260 -- (however this is not set if we are not generating code or if this
7261 -- is an anonymous type used just for resolution).
7269 -- Generic types are never seen by the back-end, and are also not
7270 -- processed by the expander (since the expander is turned off for
7271 -- generic processing), so we never need freeze nodes for them.
7277 -- Some special processing for non-generic types to complete
7278 -- representation details not known till the freeze point.
7290 and then Warn_On_Suspicious_Modulus_Value
7291 then
7295 -- The pool applies to named and anonymous access types, but not
7296 -- to subprogram and to internal types generated for 'Access
7297 -- references.
7301 then
7302 -- If a pragma Default_Storage_Pool applies, and this type has no
7303 -- Storage_Pool or Storage_Size clause (which must have occurred
7304 -- before the freezing point), then use the default. This applies
7305 -- only to base types.
7307 -- None of this applies to access to subprograms, for which there
7308 -- are clearly no pools.
7314 then
7315 -- Case of pragma Default_Storage_Pool (null)
7320 -- Case of pragma Default_Storage_Pool (Standard)
7325 -- Case of pragma Default_Storage_Pool (storage_pool_NAME)
7327 else
7332 -- Check restriction for standard storage pool
7338 -- Deal with error message for pure access type. This is not an
7339 -- error in Ada 2005 if there is no pool (see AI-366).
7345 then
7349 Error_Msg_N
7353 Error_Msg_N
7356 else
7357 Error_Msg_N
7364 -- Case of composite types
7368 -- AI95-117 requires that all new primitives of a tagged type must
7369 -- inherit the convention of the full view of the type. Inherited
7370 -- and overriding operations are defined to inherit the convention
7371 -- of their parent or overridden subprogram (also specified in
7372 -- AI-117), which will have occurred earlier (in Derive_Subprogram
7373 -- and New_Overloaded_Entity). Here we set the convention of
7374 -- primitives that are still convention Ada, which will ensure
7375 -- that any new primitives inherit the type's convention. Class-
7376 -- wide types can have a foreign convention inherited from their
7377 -- specific type, but are excluded from this since they don't have
7378 -- any associated primitives.
7383 then
7384 declare
7388 begin
7400 -- If the type is a simple storage pool type, then this is where
7401 -- we attempt to locate and validate its Allocate, Deallocate, and
7402 -- Storage_Size operations (the first is required, and the latter
7403 -- two are optional). We also verify that the full type for a
7404 -- private type is allowed to be a simple storage pool type.
7408 then
7409 -- If the type is marked Has_Private_Declaration, then this is
7410 -- a full type for a private type that was specified with the
7411 -- pragma Simple_Storage_Pool_Type, and here we ensure that the
7412 -- pragma is allowed for the full type (for example, it can't
7413 -- be an array type, or a nonlimited record type).
7418 then
7420 Error_Msg_N
7431 procedure Validate_Simple_Pool_Op_Formal
7438 -- Validate one formal Pool_Op_Formal of the candidate pool
7439 -- operation Pool_Op. The formal must be of Expected_Type
7440 -- and have mode Expected_Mode. OK_Formal will be set to
7441 -- False if the formal doesn't match. If OK_Formal is False
7442 -- on entry, then the formal will effectively be ignored
7443 -- (because validation of the pool op has already failed).
7444 -- Upon return, Pool_Op_Formal will be updated to the next
7445 -- formal, if any.
7447 procedure Validate_Simple_Pool_Operation
7449 -- Search for and validate a simple pool operation with the
7450 -- name Op_Name. If the name is Allocate, then there must be
7451 -- exactly one such primitive operation for the simple pool
7452 -- type. If the name is Deallocate or Storage_Size, then
7453 -- there can be at most one such primitive operation. The
7454 -- profile of the located primitive must conform to what
7455 -- is expected for each operation.
7457 ------------------------------------
7458 -- Validate_Simple_Pool_Op_Formal --
7459 ------------------------------------
7461 procedure Validate_Simple_Pool_Op_Formal
7468 is
7469 begin
7470 -- If OK_Formal is False on entry, then simply ignore
7471 -- the formal, because an earlier formal has already
7472 -- been flagged.
7477 -- If no formal is passed in, then issue an error for a
7478 -- missing formal.
7481 Error_Msg_NE
7491 -- If the pool type was expected for this formal, then
7492 -- this will not be considered a candidate operation
7493 -- for the simple pool, so we unset OK_Formal so that
7494 -- the op and any later formals will be ignored.
7501 else
7502 Error_Msg_NE
7509 -- Issue error if formal's mode is not the expected one
7512 Error_Msg_N
7514 Pool_Op_Formal);
7517 -- Advance to the next formal
7522 ------------------------------------
7523 -- Validate_Simple_Pool_Operation --
7524 ------------------------------------
7526 procedure Validate_Simple_Pool_Operation
7528 is
7534 begin
7535 pragma Assert
7537 | Name_Deallocate
7538 | Name_Storage_Size);
7542 -- For each homonym declared immediately in the scope
7543 -- of the simple storage pool type, determine whether
7544 -- the homonym is an operation of the pool type, and,
7545 -- if so, check that its profile is as expected for
7546 -- a simple pool operation of that name.
7552 then
7557 -- The first parameter must be of the pool type
7558 -- in order for the operation to qualify.
7561 Validate_Simple_Pool_Op_Formal
7564 else
7565 Validate_Simple_Pool_Op_Formal
7570 -- If another operation with this name has already
7571 -- been located for the type, then flag an error,
7572 -- since we only allow the type to have a single
7573 -- such primitive.
7576 Error_Msg_NE
7581 -- In the case of Allocate and Deallocate, a formal
7582 -- of type System.Address is required.
7585 Validate_Simple_Pool_Op_Formal
7590 Validate_Simple_Pool_Op_Formal
7595 -- In the case of Allocate and Deallocate, formals
7596 -- of type Storage_Count are required as the third
7597 -- and fourth parameters.
7600 Validate_Simple_Pool_Op_Formal
7603 Validate_Simple_Pool_Op_Formal
7608 -- If no mismatched formals have been found (Is_OK)
7609 -- and no excess formals are present, then this
7610 -- operation has been validated, so record it.
7620 -- There must be a valid Allocate operation for the type,
7621 -- so issue an error if none was found.
7625 then
7631 -- Simple pool operations can't be abstract
7634 Error_Msg_N
7639 -- The Storage_Size operation must be a function with
7640 -- Storage_Count as its result type.
7644 Error_Msg_N
7648 Error_Msg_NE
7653 -- Allocate and Deallocate must be procedures
7656 Error_Msg_N
7662 -- Start of processing for Validate_Simple_Pool_Ops
7664 begin
7672 -- Now that all types from which E may depend are frozen, see if
7673 -- strict alignment is required, a component clause on a record
7674 -- is correct, the size is known at compile time and if it must
7675 -- be unsigned, in that order.
7682 declare
7684 begin
7695 -- Do not allow a size clause for a type which does not have a size
7696 -- that is known at compile time
7700 then
7701 -- Suppress this message if errors posted on E, even if we are
7702 -- in all errors mode, since this is often a junk message
7705 Error_Msg_N
7711 -- Now we set/verify the representation information, in particular
7712 -- the size and alignment values. This processing is not required for
7713 -- generic types, since generic types do not play any part in code
7714 -- generation, and so the size and alignment values for such types
7715 -- are irrelevant. Ditto for types declared within a generic unit,
7716 -- which may have components that depend on generic parameters, and
7717 -- that will be recreated in an instance.
7722 -- Otherwise we call the layout procedure
7724 else
7728 -- If this is an access to subprogram whose designated type is itself
7729 -- a subprogram type, the return type of this anonymous subprogram
7730 -- type must be decorated as well.
7734 then
7738 -- If the type has a Defaut_Value/Default_Component_Value aspect,
7739 -- this is where we analyze the expression (after the type is frozen,
7740 -- since in the case of Default_Value, we are analyzing with the
7741 -- type itself, and we treat Default_Component_Value similarly for
7742 -- the sake of uniformity).
7745 declare
7750 begin
7755 else
7766 Flag_Non_Static_Expr
7773 -- Verify at this point that No_Controlled_Parts and No_Task_Parts,
7774 -- when specified on the current type or one of its ancestors, has
7775 -- not been overridden and that no violation of the aspect has
7776 -- occurred.
7778 -- It is important that we perform the checks here after the type has
7779 -- been processed because if said type depended on a private type it
7780 -- will not have been marked controlled or having tasks.
7785 -- End of freeze processing for type entities
7788 -- Here is where we logically freeze the current entity. If it has a
7789 -- freeze node, then this is the point at which the freeze node is
7790 -- linked into the result list.
7794 -- If a freeze node is already allocated, use it, otherwise allocate
7795 -- a new one. The preallocation happens in the case of anonymous base
7796 -- types, where we preallocate so that we can set First_Subtype_Link.
7797 -- Note that we reset the Sloc to the current freeze location.
7803 else
7814 -- A final pass over record types with discriminants. If the type
7815 -- has an incomplete declaration, there may be constrained access
7816 -- subtypes declared elsewhere, which do not depend on the discrimi-
7817 -- nants of the type, and which are used as component types (i.e.
7818 -- the full view is a recursive type). The designated types of these
7819 -- subtypes can only be elaborated after the type itself, and they
7820 -- need an itype reference.
7823 declare
7828 begin
7837 then
7849 -- When a type is frozen, the first subtype of the type is frozen as
7850 -- well (RM 13.14(15)). This has to be done after freezing the type,
7851 -- since obviously the first subtype depends on its own base type.
7856 -- If we just froze a tagged non-class-wide record, then freeze the
7857 -- corresponding class-wide type. This must be done after the tagged
7858 -- type itself is frozen, because the class-wide type refers to the
7859 -- tagged type which generates the class.
7861 -- For a tagged type, freeze explicitly those primitive operations
7862 -- that are expression functions, which otherwise have no clear
7863 -- freeze point: these have to be frozen before the dispatch table
7864 -- for the type is built, and before any explicit call to the
7865 -- primitive, which would otherwise be the freeze point for it.
7870 then
7873 declare
7879 begin
7897 -- If subprogram has address clause then reset Is_Public flag, since we
7898 -- do not want the backend to generate external references.
7903 then
7907 -- The Ghost mode of the enclosing context is ignored, while the
7908 -- entity being frozen is living. Insert the freezing action prior
7909 -- to the start of the enclosing ignored Ghost region. As a result
7910 -- the freezeing action will be preserved when the ignored Ghost
7911 -- context is eliminated. The insertion must take place even when
7912 -- the context is a spec expression, otherwise "Handling of Default
7913 -- and Per-Object Expressions" will suppress the insertion, and the
7914 -- freeze node will be dropped on the floor.
7919 then
7920 Insert_Actions
7934 -----------------------------
7935 -- Freeze_Enumeration_Type --
7936 -----------------------------
7939 begin
7940 -- By default, if no size clause is present, an enumeration type with
7941 -- Convention C is assumed to interface to a C enum and has integer
7942 -- size, except for a boolean type because it is assumed to interface
7943 -- to _Bool introduced in C99. This applies to types. For subtypes,
7944 -- verify that its base type has no size clause either. Treat other
7945 -- foreign conventions in the same way, and also make sure alignment
7946 -- is set right.
7954 -- Don't do this if Short_Enums on target
7956 and then not Target_Short_Enums
7957 then
7961 -- Normal Ada case or size clause present or not Long_C_Enums on target
7963 else
7964 -- If the enumeration type interfaces to C, and it has a size clause
7965 -- that is smaller than the size of int, it warrants a warning. The
7966 -- user may intend the C type to be a boolean or a char, so this is
7967 -- not by itself an error that the Ada compiler can detect, but it
7968 -- is worth a heads-up. For Boolean and Character types we
7969 -- assume that the programmer has the proper C type in mind.
7970 -- For explicit sizes larger than int, assume the user knows what
7971 -- he is doing and that the code is intentional.
7979 -- Don't do this if Short_Enums on target
7981 and then not Target_Short_Enums
7982 then
7983 Error_Msg_N
7986 Error_Msg_N
7996 -----------------------
7997 -- Freeze_Expression --
7998 -----------------------
8003 -- If the expression is an array aggregate, the type of the component
8004 -- expressions is also frozen. If the component type is an access type
8005 -- and the expressions include allocators, the designed type is frozen
8006 -- as well.
8009 -- Given an N_Handled_Sequence_Of_Statements node, determines whether it
8010 -- is the statement sequence of an expander-generated subprogram: body
8011 -- created for an expression function, for a predicate function, an init
8012 -- proc, a stream subprogram, or a renaming as body. If so, this is not
8013 -- a freezing context and the entity will be frozen at a later point.
8015 function Has_Decl_In_List
8019 -- Determines whether an entity E referenced in node N is declared in
8020 -- the list L.
8022 -----------------------------------------
8023 -- Find_Aggregate_Component_Desig_Type --
8024 -----------------------------------------
8030 begin
8056 ----------------------
8057 -- In_Expanded_Body --
8058 ----------------------
8064 begin
8068 -- AI12-0157: An expression function that is a completion is a freeze
8069 -- point. If the body is the result of expansion, it is not.
8074 -- This is the body of a generated predicate function
8078 then
8081 else
8084 -- The following are expander-created bodies, or bodies that
8085 -- are not freeze points.
8095 N_Subprogram_Renaming_Declaration)
8096 then
8098 else
8104 ----------------------
8105 -- Has_Decl_In_List --
8106 ----------------------
8108 function Has_Decl_In_List
8112 is
8115 begin
8116 -- If E is an itype, pretend that it is declared in N
8120 else
8128 -- Local variables
8141 -- This flag is set true if the entity must be frozen outside the
8142 -- current subprogram. This happens in the case of expander generated
8143 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
8144 -- not freeze all entities like other bodies, but which nevertheless
8145 -- may reference entities that have to be frozen before the body and
8146 -- obviously cannot be frozen inside the body.
8149 -- This entity is set if we are inside a subprogram body and the frozen
8150 -- entity is defined in the enclosing scope of this subprogram. In such
8151 -- case we must skip the subprogram body when climbing the parents chain
8152 -- to locate the correct placement for the freezing node.
8154 -- Start of processing for Freeze_Expression
8156 begin
8157 -- Immediate return if freezing is inhibited. This flag is set by the
8158 -- analyzer to stop freezing on generated expressions that would cause
8159 -- freezing if they were in the source program, but which are not
8160 -- supposed to freeze, since they are created.
8166 -- If expression is non-static, then it does not freeze in a default
8167 -- expression, see section "Handling of Default Expressions" in the
8168 -- spec of package Sem for further details. Note that we have to make
8169 -- sure that we actually have a real expression (if we have a subtype
8170 -- indication, we can't test Is_OK_Static_Expression). However, we
8171 -- exclude the case of the prefix of an attribute of a static scalar
8172 -- subtype from this early return, because static subtype attributes
8173 -- should always cause freezing, even in default expressions, but
8174 -- the attribute may not have been marked as static yet (because in
8175 -- Resolve_Attribute, the call to Eval_Attribute follows the call of
8176 -- Freeze_Expression on the prefix).
8178 if In_Spec_Exp
8185 then
8189 -- Freeze type of expression if not frozen already
8197 -- Base type may be an derived numeric type that is frozen at the
8198 -- point of declaration, but first_subtype is still unfrozen.
8205 -- For entity name, freeze entity if not frozen already. A special
8206 -- exception occurs for an identifier that did not come from source.
8207 -- We don't let such identifiers freeze a non-internal entity, i.e.
8208 -- an entity that did come from source, since such an identifier was
8209 -- generated by the expander, and cannot have any semantic effect on
8210 -- the freezing semantics. For example, this stops the parameter of
8211 -- an initialization procedure from freezing the variable.
8219 then
8226 else
8230 -- For an allocator freeze designated type if not frozen already
8232 -- For an aggregate whose component type is an access type, freeze the
8233 -- designated type now, so that its freeze does not appear within the
8234 -- loop that might be created in the expansion of the aggregate. If the
8235 -- designated type is a private type without full view, the expression
8236 -- cannot contain an allocator, so the type is not frozen.
8238 -- For a function, we freeze the entity when the subprogram declaration
8239 -- is frozen, but a function call may appear in an initialization proc.
8240 -- before the declaration is frozen. We need to generate the extra
8241 -- formals, if any, to ensure that the expansion of the call includes
8242 -- the proper actuals. This only applies to Ada subprograms, not to
8243 -- imported ones.
8258 then
8259 -- Check whether aggregate includes allocators
8264 when N_Indexed_Component
8265 | N_Selected_Component
8266 | N_Slice
8267 =>
8277 then
8288 then
8292 -- All done if nothing needs freezing
8298 then
8302 -- Check if we are inside a subprogram body and the frozen entity is
8303 -- defined in the enclosing scope of this subprogram. In such case we
8304 -- must skip the subprogram when climbing the parents chain to locate
8305 -- the correct placement for the freezing node.
8307 -- This is not needed for default expressions and other spec expressions
8308 -- in generic units since the Move_Freeze_Nodes mechanism (sem_ch12.adb)
8309 -- takes care of placing them at the proper place, after the generic
8310 -- unit.
8315 then
8316 declare
8319 begin
8322 loop
8336 -- Examine the enclosing context by climbing the parent chain
8338 -- If we identified that we must freeze the entity outside of a given
8339 -- subprogram then we just climb up to that subprogram checking if some
8340 -- enclosing node is marked as Must_Not_Freeze (since in such case we
8341 -- must not freeze yet this entity).
8346 loop
8347 -- Do not freeze the current expression if another expression in
8348 -- the chain of parents must not be frozen.
8356 -- If we don't have a parent, then we are not in a well-formed
8357 -- tree. This is an unusual case, but there are some legitimate
8358 -- situations in which this occurs, notably when the expressions
8359 -- in the range of a type declaration are resolved. We simply
8360 -- ignore the freeze request in this case.
8366 -- If the parent is a subprogram body, the candidate insertion
8367 -- point is just ahead of it.
8371 Freeze_Outside_Subp
8372 then
8380 -- Otherwise the traversal serves two purposes - to detect scenarios
8381 -- where freezeing is not needed and to find the proper insertion point
8382 -- for the freeze nodes. Although somewhat similar to Insert_Actions,
8383 -- this traversal is freezing semantics-sensitive. Inserting freeze
8384 -- nodes blindly in the tree may result in types being frozen too early.
8386 else
8387 loop
8388 -- Do not freeze the current expression if another expression in
8389 -- the chain of parents must not be frozen.
8397 -- If we don't have a parent, then we are not in a well-formed
8398 -- tree. This is an unusual case, but there are some legitimate
8399 -- situations in which this occurs, notably when the expressions
8400 -- in the range of a type declaration are resolved. We simply
8401 -- ignore the freeze request in this case.
8407 -- See if we have got to an appropriate point in the tree
8411 -- A special test for the exception of (RM 13.14(8)) for the
8412 -- case of per-object expressions (RM 3.8(18)) occurring in
8413 -- component definition or a discrete subtype definition. Note
8414 -- that we test for a component declaration which includes both
8415 -- cases we are interested in, and furthermore the tree does
8416 -- not have explicit nodes for either of these two constructs.
8420 -- The case we want to test for here is an identifier that
8421 -- is a per-object expression, this is either a discriminant
8422 -- that appears in a context other than the component
8423 -- declaration or it is a reference to the type of the
8424 -- enclosing construct.
8426 -- For either of these cases, we skip the freezing
8428 if not In_Spec_Expression
8431 then
8432 -- We recognize the discriminant case by just looking for
8433 -- a reference to a discriminant. It can only be one for
8434 -- the enclosing construct. Skip freezing in this case.
8439 -- For the case of a reference to the enclosing record,
8440 -- (or task or protected type), we look for a type that
8441 -- matches the current scope.
8448 -- If we have an enumeration literal that appears as the choice
8449 -- in the aggregate of an enumeration representation clause,
8450 -- then freezing does not occur (RM 13.14(10)).
8454 -- The case we are looking for is an enumeration literal
8458 then
8459 -- If enumeration literal appears directly as the choice,
8460 -- do not freeze (this is the normal non-overloaded case)
8464 then
8467 -- If enumeration literal appears as the name of function
8468 -- which is the choice, then also do not freeze. This
8469 -- happens in the overloaded literal case, where the
8470 -- enumeration literal is temporarily changed to a
8471 -- function call for overloading analysis purposes.
8475 N_Component_Association
8478 then
8483 -- Normally if the parent is a handled sequence of statements,
8484 -- then the current node must be a statement, and that is an
8485 -- appropriate place to insert a freeze node.
8489 -- An exception occurs when the sequence of statements is
8490 -- for an expander generated body that did not do the usual
8491 -- freeze all operation. In this case we usually want to
8492 -- freeze outside this body, not inside it, and we skip
8493 -- past the subprogram body that we are inside.
8496 declare
8500 begin
8501 -- Freeze the entity only when it is declared inside
8502 -- the body of the expander generated procedure. This
8503 -- case is recognized by the subprogram scope of the
8504 -- entity or its type, which is either the spec of an
8505 -- enclosing body, or (in the case of init_procs for
8506 -- which there is no separate spec) the current scope.
8509 declare
8512 begin
8519 else
8525 loop
8534 and then
8536 then
8542 -- If the entity is not frozen by an expression
8543 -- function that is not a completion, continue
8544 -- climbing the tree.
8548 then
8551 -- Freeze outside the body
8553 else
8559 -- Here if normal case where we are in handled statement
8560 -- sequence and want to do the insertion right there.
8562 else
8566 -- If parent is a body or a spec or a block, then the current
8567 -- node is a statement or declaration and we can insert the
8568 -- freeze node before it.
8570 when N_Block_Statement
8571 | N_Entry_Body
8572 | N_Package_Body
8573 | N_Package_Specification
8574 | N_Protected_Body
8575 | N_Subprogram_Body
8576 | N_Task_Body
8577 =>
8580 -- The expander is allowed to define types in any statements
8581 -- list, so any of the following parent nodes also mark a
8582 -- freezing point if the actual node is in a list of
8583 -- statements or declarations.
8585 when N_Abortable_Part
8586 | N_Accept_Alternative
8587 | N_Case_Statement_Alternative
8588 | N_Compilation_Unit_Aux
8589 | N_Conditional_Entry_Call
8590 | N_Delay_Alternative
8591 | N_Elsif_Part
8592 | N_Entry_Call_Alternative
8593 | N_Exception_Handler
8594 | N_Extended_Return_Statement
8595 | N_Freeze_Entity
8596 | N_If_Statement
8597 | N_Selective_Accept
8598 | N_Triggering_Alternative
8599 =>
8602 -- The freeze nodes produced by an expression coming from the
8603 -- Actions list of an N_Expression_With_Actions, short-circuit
8604 -- expression or N_Case_Expression_Alternative node must remain
8605 -- within the Actions list if they freeze an entity declared in
8606 -- this list, as inserting the freeze nodes further up the tree
8607 -- may lead to use before declaration issues for the entity.
8609 when N_Case_Expression_Alternative
8610 | N_Expression_With_Actions
8611 | N_Short_Circuit
8612 =>
8614 and then
8617 and then
8620 -- Likewise for an N_If_Expression and its two Actions list
8623 declare
8627 begin
8629 and then
8632 and then
8635 and then
8638 and then
8642 -- N_Loop_Statement is a special case: a type that appears in
8643 -- the source can never be frozen in a loop (this occurs only
8644 -- because of a loop expanded by the expander), so we keep on
8645 -- going. Otherwise we terminate the search. Same is true of
8646 -- any entity which comes from source (if it has a predefined
8647 -- type, this type does not appear to come from source, but the
8648 -- entity should not be frozen here).
8654 -- For all other cases, keep looking at parents
8660 -- We fall through the case if we did not yet find the proper
8661 -- place in the tree for inserting the freeze node, so climb.
8667 -- If the expression appears in a record or an initialization procedure,
8668 -- the freeze nodes are collected and attached to the current scope, to
8669 -- be inserted and analyzed on exit from the scope, to insure that
8670 -- generated entities appear in the correct scope. If the expression is
8671 -- a default for a discriminant specification, the scope is still void.
8672 -- The expression can also appear in the discriminant part of a private
8673 -- or concurrent type.
8675 -- If the expression appears in a constrained subcomponent of an
8676 -- enclosing record declaration, the freeze nodes must be attached to
8677 -- the outer record type so they can eventually be placed in the
8678 -- enclosing declaration list.
8680 -- The other case requiring this special handling is if we are in a
8681 -- default expression, since in that case we are about to freeze a
8682 -- static type, and the freeze scope needs to be the outer scope, not
8683 -- the scope of the subprogram with the default parameter.
8685 -- For default expressions and other spec expressions in generic units,
8686 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
8687 -- placing them at the proper place, after the generic unit.
8690 or else Freeze_Outside
8695 then
8696 declare
8700 begin
8713 -- The current scope may be that of a constrained component of
8714 -- an enclosing record declaration, or of a loop of an enclosing
8715 -- quantified expression, which is above the current scope in the
8716 -- scope stack. Indeed in the context of a quantified expression,
8717 -- a scope is created and pushed above the current scope in order
8718 -- to emulate the loop-like behavior of the quantified expression.
8719 -- If the expression is within a top-level pragma, as for a pre-
8720 -- condition on a library-level subprogram, nothing to do.
8725 N_Quantified_Expression)
8726 then
8732 -- When the current scope is transient, insert the freeze nodes
8733 -- prior to the expression that produced them. Transient scopes
8734 -- may create additional declarations when finalizing objects
8735 -- or managing the secondary stack. Inserting the freeze nodes
8736 -- of those constructs prior to the scope would result in a
8737 -- freeze-before-declaration, therefore the freeze node must
8738 -- remain interleaved with their constructs.
8745 Freeze_Nodes;
8746 else
8756 -- Now we have the right place to do the freezing. First, a special
8757 -- adjustment, if we are in spec-expression analysis mode, these freeze
8758 -- actions must not be thrown away (normally all inserted actions are
8759 -- thrown away in this mode. However, the freeze actions are from static
8760 -- expressions and one of the important reasons we are doing this
8761 -- special analysis is to get these freeze actions. Therefore we turn
8762 -- off the In_Spec_Expression mode to propagate these freeze actions.
8763 -- This also means they get properly analyzed and expanded.
8767 -- Freeze the subtype mark before a qualified expression on an
8768 -- allocator as per AARM 13.14(4.a). This is needed in particular to
8769 -- generate predicate functions.
8775 -- Freeze the designated type of an allocator (RM 13.14(13))
8781 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
8782 -- the enumeration representation clause exception in the loop above.
8788 -- Freeze name if one is present (RM 13.14(11))
8794 -- Restore In_Spec_Expression flag
8799 -----------------------
8800 -- Freeze_Expr_Types --
8801 -----------------------
8803 procedure Freeze_Expr_Types
8808 is
8810 -- Build a duplicate of the expression of the return statement that has
8811 -- no defining entities shared with the original expression.
8814 -- Freeze all types referenced in the subtree rooted at Node
8816 -----------------------
8817 -- Cloned_Expression --
8818 -----------------------
8822 -- Tree traversal routine that clones the defining identifier of
8823 -- iterator and loop parameter specification nodes.
8825 --------------
8826 -- Clone_Id --
8827 --------------
8830 begin
8832 N_Iterator_Specification | N_Loop_Parameter_Specification
8833 then
8834 Set_Defining_Identifier
8843 -- Local variable
8847 -- Start of processing for Cloned_Expression
8849 begin
8850 -- We must duplicate the expression with semantic information to
8851 -- inherit the decoration of global entities in generic instances.
8852 -- Set the parent of the new node to be the parent of the original
8853 -- to get the proper context, which is needed for complete error
8854 -- reporting and for semantic analysis.
8858 -- Replace the defining identifier of iterators and loop param
8859 -- specifications by a clone to ensure that the cloned expression
8860 -- and the original expression don't have shared identifiers;
8861 -- otherwise, as part of the preanalysis of the expression, these
8862 -- shared identifiers may be left decorated with itypes which
8863 -- will not be available in the tree passed to the backend.
8870 ----------------------
8871 -- Freeze_Type_Refs --
8872 ----------------------
8876 -- Check that Typ is fully declared and freeze it if so
8878 ---------------------------
8879 -- Check_And_Freeze_Type --
8880 ---------------------------
8883 begin
8884 -- Skip Itypes created by the preanalysis, and itypes whose
8885 -- scope is another type (i.e. component subtypes that depend
8886 -- on a discriminant),
8891 then
8895 -- This provides a better error message than generating primitives
8896 -- whose compilation fails much later. Refine the error message if
8897 -- possible.
8904 then
8908 else
8913 -- Start of processing for Freeze_Type_Refs
8915 begin
8916 -- Check that a type referenced by an entity can be frozen
8919 -- The entity itself may be a type, as in a membership test
8920 -- or an attribute reference. Freezing its own type would be
8921 -- incomplete if the entity is derived or an extension.
8926 else
8930 -- Check that the enclosing record type can be frozen
8936 -- Freezing an access type does not freeze the designated type, but
8937 -- freezing conversions between access to interfaces requires that
8938 -- the interface types themselves be frozen, so that dispatch table
8939 -- entities are properly created.
8941 -- Unclear whether a more general rule is needed ???
8946 then
8950 -- An implicit dereference freezes the designated type. In the case
8951 -- of a dispatching call whose controlling argument is an access
8952 -- type, the dereference is not made explicit, so we must check for
8953 -- such a call and freeze the designated type.
8958 then
8961 then
8964 -- An explicit dereference freezes the designated type as well,
8965 -- even though that type is not attached to an entity in the
8966 -- expression.
8972 -- An iterator specification freezes the iterator type, even though
8973 -- that type is not attached to an entity in the construct.
8978 then
8979 declare
8983 begin
8990 -- No point in posting several errors on the same expression
8994 else
9001 -- Local variables
9007 -- Start of processing for Freeze_Expr_Types
9009 begin
9010 -- Preanalyze a duplicate of the expression to have available the
9011 -- minimum decoration needed to locate referenced unfrozen types
9012 -- without adding any decoration to the function expression.
9014 -- This routine is also applied to expressions in the contract for
9015 -- the subprogram. If that happens when expanding the code for
9016 -- pre/postconditions during expansion of the subprogram body, the
9017 -- subprogram is already installed.
9024 End_Scope;
9025 else
9029 -- Restore certain attributes of Def_Id since the preanalysis may
9030 -- have introduced itypes to this scope, thus modifying attributes
9031 -- First_Entity and Last_Entity.
9040 -- Freeze all types referenced in the expression
9045 -----------------------------
9046 -- Freeze_Fixed_Point_Type --
9047 -----------------------------
9049 -- Certain fixed-point types and subtypes, including implicit base types
9050 -- and declared first subtypes, have not yet set up a range. This is
9051 -- because the range cannot be set until the Small and Size values are
9052 -- known, and these are not known till the type is frozen.
9054 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
9055 -- whose bounds are unanalyzed real literals. This routine will recognize
9056 -- this case, and transform this range node into a properly typed range
9057 -- with properly analyzed and resolved values.
9076 -- Save original bounds (for shaving tests)
9079 -- Actual size chosen
9082 -- Returns size of type with given bounds. Also leaves these
9083 -- bounds set as the current bounds of the Typ.
9086 -- Returns true if A > B with a margin of Typ'Small
9089 -- Returns true if A < B with a margin of Typ'Small
9091 -----------
9092 -- Fsize --
9093 -----------
9096 begin
9102 ------------
9103 -- Larger --
9104 ------------
9107 begin
9111 -------------
9112 -- Smaller --
9113 -------------
9116 begin
9120 -- Start of processing for Freeze_Fixed_Point_Type
9122 begin
9123 -- The type, or its first subtype if we are freezing the anonymous
9124 -- base, may have a delayed Small aspect. It must be analyzed now,
9125 -- so that all characteristics of the type (size, bounds) can be
9126 -- computed and validated in the call to Minimum_Size that follows.
9138 -- Inherit the Small value from the first subtype in any case
9144 -- If Esize of a subtype has not previously been set, set it now
9151 else
9156 -- Immediate return if the range is already analyzed. This means that
9157 -- the range is already set, and does not need to be computed by this
9158 -- routine.
9164 -- Immediate return if either of the bounds raises Constraint_Error
9168 then
9179 -- Ordinary fixed-point case
9183 -- For the ordinary fixed-point case, we are allowed to fudge the
9184 -- end-points up or down by small. Generally we prefer to fudge up,
9185 -- i.e. widen the bounds for non-model numbers so that the end points
9186 -- are included. However there are cases in which this cannot be
9187 -- done, and indeed cases in which we may need to narrow the bounds.
9188 -- The following circuit makes the decision.
9190 -- Note: our terminology here is that Incl_EP means that the bounds
9191 -- are widened by Small if necessary to include the end points, and
9192 -- Excl_EP means that the bounds are narrowed by Small to exclude the
9193 -- end-points if this reduces the size.
9195 -- Note that in the Incl case, all we care about is including the
9196 -- end-points. In the Excl case, we want to narrow the bounds as
9197 -- much as permitted by the RM, to give the smallest possible size.
9213 begin
9214 -- First step. Base types are required to be symmetrical. Right
9215 -- now, the base type range is a copy of the first subtype range.
9216 -- This will be corrected before we are done, but right away we
9217 -- need to deal with the case where both bounds are non-negative.
9218 -- In this case, we set the low bound to the negative of the high
9219 -- bound, to make sure that the size is computed to include the
9220 -- required sign. Note that we do not need to worry about the
9221 -- case of both bounds negative, because the sign will be dealt
9222 -- with anyway. Furthermore we can't just go making such a bound
9223 -- symmetrical, since in a twos-complement system, there is an
9224 -- extra negative value which could not be accommodated on the
9225 -- positive side.
9230 then
9235 -- Compute the fudged bounds. If the bound is a model number, (or
9236 -- greater if given low bound, smaller if high bound) then we do
9237 -- nothing to include it, but we are allowed to backoff to the
9238 -- next adjacent model number when we exclude it. If it is not a
9239 -- model number then we straddle the two values with the model
9240 -- numbers on either side.
9246 else
9250 -- The low value excluding the end point is Small greater, but
9251 -- we do not do this exclusion if the low value is positive,
9252 -- since it can't help the size and could actually hurt by
9253 -- crossing the high bound.
9258 -- If the value went from negative to zero, then we have the
9259 -- case where Loval_Incl_EP is the model number just below
9260 -- zero, so we want to stick to the negative value for the
9261 -- base type to maintain the condition that the size will
9262 -- include signed values.
9266 then
9270 else
9274 -- Similar processing for upper bound and high value
9280 else
9286 else
9290 -- One further adjustment is needed. In the case of subtypes, we
9291 -- cannot go outside the range of the base type, or we get
9292 -- peculiarities, and the base type range is already set. This
9293 -- only applies to the Incl values, since clearly the Excl values
9294 -- are already as restricted as they are allowed to be.
9301 -- Get size including and excluding end points
9306 -- No need to exclude end-points if it does not reduce size
9316 -- Now we set the actual size to be used. We want to use the
9317 -- bounds fudged up to include the end-points but only if this
9318 -- can be done without violating a specifically given size
9319 -- size clause or causing an unacceptable increase in size.
9321 -- Case of size clause given
9325 -- Use the inclusive size only if it is consistent with
9326 -- the explicitly specified size.
9333 -- If the inclusive size is too large, we try excluding
9334 -- the end-points (will be caught later if does not work).
9336 else
9342 -- Case of size clause not given
9344 else
9345 -- If we have a base type whose corresponding first subtype
9346 -- has an explicit size that is large enough to include our
9347 -- end-points, then do so. There is no point in working hard
9348 -- to get a base type whose size is smaller than the specified
9349 -- size of the first subtype.
9353 then
9358 -- If excluding the end-points makes the size smaller and
9359 -- results in a size of 8,16,32,64, then we take the smaller
9360 -- size. For the 64 case, this is compulsory. For the other
9361 -- cases, it seems reasonable. We like to include end points
9362 -- if we can, but not at the expense of moving to the next
9363 -- natural boundary of size.
9367 then
9372 -- Otherwise we can definitely include the end points
9374 else
9380 -- One pathological case: normally we never fudge a low bound
9381 -- down, since it would seem to increase the size (if it has
9382 -- any effect), but for ranges containing single value, or no
9383 -- values, the high bound can be small too large. Consider:
9385 -- type t is delta 2.0**(-14)
9386 -- range 131072.0 .. 0;
9388 -- That lower bound is *just* outside the range of 32 bits, and
9389 -- does need fudging down in this case. Note that the bounds
9390 -- will always have crossed here, since the high bound will be
9391 -- fudged down if necessary, as in the case of:
9393 -- type t is delta 2.0**(-14)
9394 -- range 131072.0 .. 131072.0;
9396 -- So we detect the situation by looking for crossed bounds,
9397 -- and if the bounds are crossed, and the low bound is greater
9398 -- than zero, we will always back it off by small, since this
9399 -- is completely harmless.
9406 -- And of course, we need to do exactly the same parallel
9407 -- fudge for flat ranges in the negative region.
9420 -- Enforce some limitations for ordinary fixed-point types. They come
9421 -- from an exact algorithm used to implement Text_IO.Fixed_IO and the
9422 -- Fore, Image and Value attributes. The requirement on the Small is
9423 -- to lie in the range 2**(-(Siz - 1)) .. 2**(Siz - 1) for a type of
9424 -- Siz bits (Siz=32,64,128) and the requirement on the bounds is to
9425 -- be smaller in magnitude than 10.0**N * 2**(Siz - 1), where N is
9426 -- given by the formula N = floor ((Siz - 1) * log 2 / log 10).
9428 -- If the bounds of a 32-bit type are too large, force 64-bit type
9434 then
9438 -- If the bounds of a 64-bit type are too large, force 128-bit type
9445 then
9449 -- Give error messages for first subtypes and not base types, as the
9450 -- bounds of base types are always maximum for their size, see below.
9454 -- See the 128-bit case below for the reason why we cannot test
9455 -- against the 2**(-63) .. 2**63 range. This quirk should have
9456 -- been kludged around as in the 128-bit case below, but it was
9457 -- not and we end up with a ludicrous range as a result???
9461 Error_Msg_N
9466 Error_Msg_N
9472 Error_Msg_N
9478 Error_Msg_N
9484 -- ACATS c35902d tests a delta equal to 2**(-(Max_Mantissa + 1))
9485 -- but we cannot really support anything smaller than Fine_Delta
9486 -- because of the way we implement I/O for fixed point types???
9493 Error_Msg_N
9498 Error_Msg_N
9506 then
9508 Error_Msg_N
9514 Error_Msg_N
9520 Error_Msg_N
9525 -- For the decimal case, none of this fudging is required, since there
9526 -- are no end-point problems in the decimal case (the end-points are
9527 -- always included).
9529 else
9533 -- At this stage, the actual size has been calculated and the proper
9534 -- required bounds are stored in the low and high bounds.
9539 Error_Msg_N
9541 Typ);
9545 -- Check size against explicit given size
9551 Error_Msg_NE
9555 else
9559 -- Increase size to next natural boundary if no size clause given
9561 else
9570 else
9578 -- If we have a base type, then expand the bounds so that they extend to
9579 -- the full width of the allocated size in bits, to avoid junk range
9580 -- checks on intermediate computations.
9587 -- Final step is to reanalyze the bounds using the proper type
9588 -- and set the Corresponding_Integer_Value fields of the literals.
9594 -- Resolve with universal fixed if the base type, and with the base
9595 -- type if we are freezing a subtype. Note we can't resolve the base
9596 -- type with itself, that would be a reference before definition.
9597 -- The resolution of the bounds of a subtype, if they are given by real
9598 -- literals, includes the setting of the Corresponding_Integer_Value,
9599 -- as for other literals of a fixed-point type.
9603 Set_Corresponding_Integer_Value
9605 else
9609 -- Similar processing for high bound
9617 Set_Corresponding_Integer_Value
9619 else
9623 -- Set type of range to correspond to bounds
9627 -- Set Esize to calculated size if not set already
9633 -- Set RM_Size if not already set. If already set, check value
9635 declare
9638 begin
9643 Error_Msg_NE
9648 else
9653 -- Check for shaving
9657 -- In SPARK mode the given bounds must be strictly representable
9661 Error_Msg_NE
9667 Error_Msg_NE
9672 else
9674 Error_Msg_N
9676 Error_Msg_N
9681 Error_Msg_N
9683 Typ);
9684 Error_Msg_N
9691 ------------------
9692 -- Freeze_Itype --
9693 ------------------
9698 begin
9705 --------------------------
9706 -- Freeze_Static_Object --
9707 --------------------------
9712 -- Exception raised if the type of a static object cannot be made
9713 -- static. This happens if the type depends on non-global objects.
9716 -- Called to ensure that an expression used as part of a type definition
9717 -- is statically allocatable, which means that the expression type is
9718 -- statically allocatable, and the expression is either static, or a
9719 -- reference to a library level constant.
9722 -- Called to mark a type as static, checking that it is possible
9723 -- to set the type as static. If it is not possible, then the
9724 -- exception Cannot_Be_Static is raised.
9726 -----------------------------
9727 -- Ensure_Expression_Is_SA --
9728 -----------------------------
9733 begin
9745 then
9753 -----------------------
9754 -- Ensure_Type_Is_SA --
9755 -----------------------
9761 begin
9762 -- If type is library level, we are all set
9768 -- We are also OK if the type already marked as statically allocated,
9769 -- which means we processed it before.
9775 -- Mark type as statically allocated
9779 -- Check that it is safe to statically allocate this type
9797 declare
9801 begin
9813 else
9822 then
9841 else
9846 -- Start of processing for Freeze_Static_Object
9848 begin
9851 exception
9854 -- If the object that cannot be static is imported or exported, then
9855 -- issue an error message saying that this object cannot be imported
9856 -- or exported. If it has an address clause it is an overlay in the
9857 -- current partition and the static requirement is not relevant.
9858 -- Do not issue any error message when ignoring rep clauses.
9865 Error_Msg_N
9869 -- Otherwise must be exported, something is wrong if compiler
9870 -- is marking something as statically allocated which cannot be).
9873 Error_Msg_N
9878 -----------------------
9879 -- Freeze_Subprogram --
9880 -----------------------
9885 -- Set the conventions of all anonymous access-to-subprogram formals and
9886 -- result subtype of subprogram Subp_Id to the convention of Subp_Id.
9888 ----------------------------
9889 -- Set_Profile_Convention --
9890 ----------------------------
9896 -- Set the convention of anonymous access-to-subprogram type Typ and
9897 -- its designated type to Conv.
9899 -------------------------
9900 -- Set_Type_Convention --
9901 -------------------------
9904 begin
9905 -- Set the convention on both the anonymous access-to-subprogram
9906 -- type and the subprogram type it points to because both types
9907 -- participate in conformance-related checks.
9915 -- Local variables
9919 -- Start of processing for Set_Profile_Convention
9921 begin
9933 -- Local variables
9938 -- Start of processing for Freeze_Subprogram
9940 begin
9941 -- Subprogram may not have an address clause unless it is imported
9945 Error_Msg_N
9951 -- Reset the Pure indication on an imported subprogram unless an
9952 -- explicit Pure_Function pragma was present or the subprogram is an
9953 -- intrinsic. We do this because otherwise it is an insidious error
9954 -- to call a non-pure function from pure unit and have calls
9955 -- mysteriously optimized away. What happens here is that the Import
9956 -- can bypass the normal check to ensure that pure units call only pure
9957 -- subprograms.
9959 -- The reason for the intrinsic exception is that in general, intrinsic
9960 -- functions (such as shifts) are pure anyway. The only exceptions are
9961 -- the intrinsics in GNAT.Source_Info, and that unit is not marked Pure
9962 -- in any case, so no problem arises.
9968 then
9972 -- For C++ constructors check that their external name has been given
9973 -- (either in pragma CPP_Constructor or in a pragma import).
9977 and then
9979 or else String_Equal
9982 then
9983 Error_Msg_N
9987 -- We also reset the Pure indication on a subprogram with an Address
9988 -- parameter, because the parameter may be used as a pointer and the
9989 -- referenced data may change even if the address value does not.
9991 -- Note that if the programmer gave an explicit Pure_Function pragma,
9992 -- then we believe the programmer, and leave the subprogram Pure. We
9993 -- also suppress this check on run-time files.
9999 then
10003 -- Ensure that all anonymous access-to-subprogram types inherit the
10004 -- convention of their related subprogram (RM 6.3.1(13.1/5)). This is
10005 -- not done for a defaulted convention Ada because those types also
10006 -- default to Ada. Convention Protected must not be propagated when
10007 -- the subprogram is an entry because this would be illegal. The only
10008 -- way to force convention Protected on these kinds of types is to
10009 -- include keyword "protected" in the access definition. Conventions
10010 -- Entry and Intrinsic are also not propagated (specified by AI12-0207).
10016 then
10020 -- For non-foreign convention subprograms, this is where we create
10021 -- the extra formals (for accessibility level and constrained bit
10022 -- information). We delay this till the freeze point precisely so
10023 -- that we know the convention.
10027 -- Extra formals of dispatching operations are added later by
10028 -- Expand_Freeze_Record_Type, which also adds extra formals to
10029 -- internal entities built to handle interface types.
10034 pragma Assert
10037 or else
10040 and then
10048 -- If this is convention Ada and a Valued_Procedure, that's odd
10053 and then Warn_On_Export_Import
10054 then
10055 Error_Msg_N
10060 -- Case of foreign convention
10062 else
10065 -- For foreign conventions, warn about return of unconstrained array
10070 -- If no return type, probably some other error, e.g. a
10071 -- missing full declaration, so ignore.
10076 -- If the return type is generic, we have emitted a warning
10077 -- earlier on, and there is nothing else to check here. Specific
10078 -- instantiations may lead to erroneous behavior.
10083 -- Display warning if returning unconstrained array
10088 -- Check appropriate warning is enabled (should we check for
10089 -- Warnings (Off) on specific entities here, probably so???)
10091 and then Warn_On_Export_Import
10092 then
10093 Error_Msg_N
10100 -- If any of the formals for an exported foreign convention
10101 -- subprogram have defaults, then emit an appropriate warning since
10102 -- this is odd (default cannot be used from non-Ada code)
10107 if Warn_On_Export_Import
10109 then
10110 Error_Msg_N
10120 -- Pragma Inline_Always is disallowed for dispatching subprograms
10121 -- because the address of such subprograms is saved in the dispatch
10122 -- table to support dispatching calls, and dispatching calls cannot
10123 -- be inlined. This is consistent with the restriction against using
10124 -- 'Access or 'Address on an Inline_Always subprogram.
10128 then
10129 Error_Msg_N
10133 -- Because of the implicit representation of inherited predefined
10134 -- operators in the front-end, the overriding status of the operation
10135 -- may be affected when a full view of a type is analyzed, and this is
10136 -- not captured by the analysis of the corresponding type declaration.
10137 -- Therefore the correctness of a not-overriding indicator must be
10138 -- rechecked when the subprogram is frozen.
10142 then
10148 if Transform_Function_Array
10154 then
10159 ----------------------
10160 -- Is_Fully_Defined --
10161 ----------------------
10164 begin
10173 then
10174 -- Verify that the record type has no components with private types
10175 -- without completion.
10177 declare
10180 begin
10192 -- For the designated type of an access to subprogram, all types in
10193 -- the profile must be fully defined.
10196 declare
10199 begin
10212 else
10218 ---------------------------------
10219 -- Process_Default_Expressions --
10220 ---------------------------------
10222 procedure Process_Default_Expressions
10225 is
10232 begin
10235 -- A subprogram instance and its associated anonymous subprogram share
10236 -- their signature. The default expression functions are defined in the
10237 -- wrapper packages for the anonymous subprogram, and should not be
10238 -- generated again for the instance.
10243 then
10251 -- We work with a copy of the default expression because we
10252 -- do not want to disturb the original, since this would mess
10253 -- up the conformance checking.
10257 -- The analysis of the expression may generate insert actions,
10258 -- which of course must not be executed. We wrap those actions
10259 -- in a procedure that is not called, and later on eliminated.
10260 -- The following cases have no side effects, and are analyzed
10261 -- directly.
10265 | N_Integer_Literal
10266 | N_Character_Literal
10267 | N_String_Literal
10268 | N_Real_Literal
10272 then
10273 -- If there is no default function, we must still do a full
10274 -- analyze call on the default value, to ensure that all error
10275 -- checks are performed, e.g. those associated with static
10276 -- evaluation. Note: this branch will always be taken if the
10277 -- analyzer is turned off (but we still need the error checks).
10279 -- Note: the setting of parent here is to meet the requirement
10280 -- that we can only analyze the expression while attached to
10281 -- the tree. Really the requirement is that the parent chain
10282 -- be set, we don't actually need to be in the tree.
10287 -- Default expressions are resolved with their own type if the
10288 -- context is generic, to avoid anomalies with private types.
10292 else
10296 -- If that resolved expression will raise constraint error,
10297 -- then flag the default value as raising constraint error.
10298 -- This allows a proper error message on the calls.
10304 -- If the default is a parameterless call, we use the name of
10305 -- the called function directly, and there is no body to build.
10309 then
10312 -- Else construct and analyze the body of a wrapper procedure
10313 -- that contains an object declaration to hold the expression.
10314 -- Given that this is done only to complete the analysis, it is
10315 -- simpler to build a procedure than a function which might
10316 -- involve secondary stack expansion.
10318 else
10321 Dbody :=
10323 Specification =>
10330 Object_Definition =>
10334 Handled_Statement_Sequence =>
10351 ----------------------------------------
10352 -- Set_Component_Alignment_If_Not_Set --
10353 ----------------------------------------
10356 begin
10357 -- Ignore if not base type, subtypes don't need anything
10363 -- Do not override existing representation
10374 else
10375 Set_Component_Alignment
10381 --------------------------
10382 -- Set_SSO_From_Default --
10383 --------------------------
10388 begin
10389 -- Set default SSO for an array or record base type, except in case of
10390 -- a type extension (which always inherits the SSO of its parent type).
10397 then
10398 Reversed :=
10400 or else
10405 -- For a record type, if bit order is specified explicitly,
10406 -- then do not set SSO from default if not consistent. Note that
10407 -- we do not want to look at a Bit_Order attribute definition
10408 -- for a parent: if we were to inherit Bit_Order, then both
10409 -- SSO_Set_*_By_Default flags would have been cleared already
10410 -- (by Inherit_Aspects_At_Freeze_Point).
10412 and then not
10414 and then
10417 then
10418 -- If flags cause reverse storage order, then set the result. Note
10419 -- that we would have ignored the pragma setting the non default
10420 -- storage order in any case, hence the assertion at this point.
10422 pragma Assert
10427 -- For a record type, also set reversed bit order. Note: if a bit
10428 -- order has been specified explicitly, then this is a no-op.
10437 ------------------
10438 -- Undelay_Type --
10439 ------------------
10442 begin
10446 -- Since we don't want T to have a Freeze_Node, we don't want its
10447 -- Full_View or Corresponding_Record_Type to have one either.
10449 -- ??? Fundamentally, this whole handling is unpleasant. What we really
10450 -- want is to be sure that for an Itype that's part of record R and is a
10451 -- subtype of type T, that it's frozen after the later of the freeze
10452 -- points of R and T. We have no way of doing that directly, so what we
10453 -- do is force most such Itypes to be frozen as part of freezing R via
10454 -- this procedure and only delay the ones that need to be delayed
10455 -- (mostly the designated types of access types that are defined as part
10456 -- of the record).
10462 then
10470 then
10475 ------------------
10476 -- Warn_Overlay --
10477 ------------------
10481 -- The object to which the address clause applies
10487 begin
10488 -- No warning if address clause overlay warnings are off
10494 -- No warning if there is an explicit initialization
10502 -- We only give the warning for non-imported entities of a type for
10503 -- which a non-null base init proc is defined, or for objects of access
10504 -- types with implicit null initialization, or when Normalize_Scalars
10505 -- applies and the type is scalar or a string type (the latter being
10506 -- tested for because predefined String types are initialized by inline
10507 -- code rather than by an init_proc). Note that we do not give the
10508 -- warning for Initialize_Scalars, since we suppressed initialization
10509 -- in this case. Also, do not warn if Suppress_Initialization is set
10510 -- either on the type, or on the object via pragma or aspect.
10522 then
10525 then
10530 then
10537 then
10544 -- A function call (most likely to To_Address) is probably not an
10545 -- overlay, so skip warning. Ditto if the function call was inlined
10546 -- and transformed into an entity.
10552 -- If a pragma Import follows, we assume that it is for the current
10553 -- target of the address clause, and skip the warning. There may be
10554 -- a source pragma or an aspect that specifies import and generates
10555 -- the corresponding pragma. These will indicate that the entity is
10556 -- imported and that is checked above so that the spurious warning
10557 -- (generated when the entity is frozen) will be suppressed. The
10558 -- pragma may be attached to the aspect, so it is not yet a list
10559 -- member.
10567 then
10572 -- Otherwise give warning message
10576 Error_Msg_N
10578 Nam);
10579 else
10580 Error_Msg_N
10582 Nam);
10585 -- Add friendly warning if initialization comes from a packed array
10586 -- component.
10589 declare
10592 begin
10597 then
10601 then
10602 Error_Msg_NE
10607 else
10614 Error_Msg_N
10617 Nam);