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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) 1992-2014, 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 ------------------------------------------------------------------------------
73 -----------------------
74 -- Local Subprograms --
75 -----------------------
78 -- Typ is a type that is being frozen. If no size clause is given,
79 -- but a default Esize has been computed, then this default Esize is
80 -- adjusted up if necessary to be consistent with a given alignment,
81 -- but never to a value greater than Long_Long_Integer'Size. This
82 -- is used for all discrete types and for fixed-point types.
84 procedure Build_And_Analyze_Renamed_Body
88 -- Build body for a renaming declaration, insert in tree and analyze
91 -- Apply legality checks to address clauses for object declarations,
92 -- at the point the object is frozen. Also ensure any initialization is
93 -- performed only after the object has been frozen.
95 procedure Check_Component_Storage_Order
100 -- For an Encl_Type that has a Scalar_Storage_Order attribute definition
101 -- clause, verify that the component type has an explicit and compatible
102 -- attribute/aspect. For arrays, Comp is Empty; for records, it is the
103 -- entity of the component under consideration. For an Encl_Type that
104 -- does not have a Scalar_Storage_Order attribute definition clause,
105 -- verify that the component also does not have such a clause.
106 -- ADC is the attribute definition clause if present (or Empty). On return,
107 -- Comp_ADC_Present is set True if the component has a Scalar_Storage_Order
108 -- attribute definition clause.
111 -- When an expression function is frozen by a use of it, the expression
112 -- itself is frozen. Check that the expression does not include references
113 -- to deferred constants without completion. We report this at the freeze
114 -- point of the function, to provide a better error message.
115 --
116 -- In most cases the expression itself is frozen by the time the function
117 -- itself is frozen, because the formals will be frozen by then. However,
118 -- Attribute references to outer types are freeze points for those types;
119 -- this routine generates the required freeze nodes for them.
122 -- E is a base type. If E is tagged or has a component that is aliased
123 -- or tagged or contains something this is aliased or tagged, set
124 -- Strict_Alignment.
128 -- If E is a fixed-point or discrete type, then all the necessary work
129 -- to freeze it is completed except for possible setting of the flag
130 -- Is_Unsigned_Type, which is done by this procedure. The call has no
131 -- effect if the entity E is not a discrete or fixed-point type.
133 procedure Freeze_And_Append
137 -- Freezes Ent using Freeze_Entity, and appends the resulting list of
138 -- nodes to Result, modifying Result from No_List if necessary. N has
139 -- the same usage as in Freeze_Entity.
142 -- Freeze enumeration type. The Esize field is set as processing
143 -- proceeds (i.e. set by default when the type is declared and then
144 -- adjusted by rep clauses. What this procedure does is to make sure
145 -- that if a foreign convention is specified, and no specific size
146 -- is given, then the size must be at least Integer'Size.
149 -- If an object is frozen which has Is_Statically_Allocated set, then
150 -- all referenced types must also be marked with this flag. This routine
151 -- is in charge of meeting this requirement for the object entity E.
154 -- Perform freezing actions for a subprogram (create extra formals,
155 -- and set proper default mechanism values). Note that this routine
156 -- is not called for internal subprograms, for which neither of these
157 -- actions is needed (or desirable, we do not want for example to have
158 -- these extra formals present in initialization procedures, where they
159 -- would serve no purpose). In this call E is either a subprogram or
160 -- a subprogram type (i.e. an access to a subprogram).
163 -- True if T is not private and has no private components, or has a full
164 -- view. Used to determine whether the designated type of an access type
165 -- should be frozen when the access type is frozen. This is done when an
166 -- allocator is frozen, or an expression that may involve attributes of
167 -- the designated type. Otherwise freezing the access type does not freeze
168 -- the designated type.
170 procedure Process_Default_Expressions
173 -- This procedure is called for each subprogram to complete processing of
174 -- default expressions at the point where all types are known to be frozen.
175 -- The expressions must be analyzed in full, to make sure that all error
176 -- processing is done (they have only been pre-analyzed). If the expression
177 -- is not an entity or literal, its analysis may generate code which must
178 -- not be executed. In that case we build a function body to hold that
179 -- code. This wrapper function serves no other purpose (it used to be
180 -- called to evaluate the default, but now the default is inlined at each
181 -- point of call).
184 -- Typ is a record or array type that is being frozen. This routine sets
185 -- the default component alignment from the scope stack values if the
186 -- alignment is otherwise not specified.
189 -- As each entity is frozen, this routine is called to deal with the
190 -- setting of Debug_Info_Needed for the entity. This flag is set if
191 -- the entity comes from source, or if we are in Debug_Generated_Code
192 -- mode or if the -gnatdV debug flag is set. However, it never sets
193 -- the flag if Debug_Info_Off is set. This procedure also ensures that
194 -- subsidiary entities have the flag set as required.
197 -- T is a record or array type that is being frozen. If it is a base type,
198 -- and if SSO_Set_Low/High_By_Default is set, then Reverse_Storage order
199 -- will be set appropriately. Note that an explicit occurrence of aspect
200 -- Scalar_Storage_Order or an explicit setting of this aspect with an
201 -- attribute definition clause occurs, then these two flags are reset in
202 -- any case, so call will have no effect.
205 -- T is a type of a component that we know to be an Itype. We don't want
206 -- this to have a Freeze_Node, so ensure it doesn't. Do the same for any
207 -- Full_View or Corresponding_Record_Type.
209 procedure Warn_Overlay
213 -- Expr is the expression for an address clause for entity Nam whose type
214 -- is Typ. If Typ has a default initialization, and there is no explicit
215 -- initialization in the source declaration, check whether the address
216 -- clause might cause overlaying of an entity, and emit a warning on the
217 -- side effect that the initialization will cause.
219 -------------------------------
220 -- Adjust_Esize_For_Alignment --
221 -------------------------------
226 begin
232 then
238 ------------------------------------
239 -- Build_And_Analyze_Renamed_Body --
240 ------------------------------------
242 procedure Build_And_Analyze_Renamed_Body
246 is
252 begin
253 -- If the renamed subprogram is intrinsic, there is no need for a
254 -- wrapper body: we set the alias that will be called and expanded which
255 -- completes the declaration. This transformation is only legal if the
256 -- renamed entity has already been elaborated.
258 -- Note that it is legal for a renaming_as_body to rename an intrinsic
259 -- subprogram, as long as the renaming occurs before the new entity
260 -- is frozen (RM 8.5.4 (5)).
264 then
266 else
272 and then
276 -- We can make the renaming entity intrinsic if the renamed function
277 -- has an interface name, or if it is one of the shift/rotate
278 -- operations known to the compiler.
280 and then
283 Name_Rotate_Right,
284 Name_Shift_Left,
285 Name_Shift_Right,
286 Name_Shift_Right_Arithmetic))
287 then
292 else
299 else
308 ------------------------
309 -- Build_Renamed_Body --
310 ------------------------
312 function Build_Renamed_Body
315 is
317 -- We use for the source location of the renamed body, the location of
318 -- the spec entity. It might seem more natural to use the location of
319 -- the renaming declaration itself, but that would be wrong, since then
320 -- the body we create would look as though it was created far too late,
321 -- and this could cause problems with elaboration order analysis,
322 -- particularly in connection with instantiations.
337 -- If the renamed entity is a primitive operation given in prefix form,
338 -- the prefix is the target object and it has to be added as the first
339 -- actual in the generated call.
341 begin
342 -- Determine the entity being renamed, which is the target of the call
343 -- statement. If the name is an explicit dereference, this is a renaming
344 -- of a subprogram type rather than a subprogram. The name itself is
345 -- fully analyzed.
356 else
363 else
369 -- If the renamed entity is a predefined operator, retain full name
370 -- to ensure its visibility.
374 then
376 else
380 else
383 and then
386 then
388 -- Retrieve the target object, to be added as a first actual
389 -- in the call.
394 else
398 -- Original name may have been overloaded, but is fully resolved now
403 -- For simple renamings, subsequent calls can be expanded directly as
404 -- calls to the renamed entity. The body must be generated in any case
405 -- for calls that may appear elsewhere. This is not done in the case
406 -- where the subprogram is an instantiation because the actual proper
407 -- body has not been built yet.
412 then
416 -- Check whether the return type is a limited view. If the subprogram
417 -- is already frozen the generated body may have a non-limited view
418 -- of the type, that must be used, because it is the one in the spec
419 -- of the renaming declaration.
423 then
424 declare
426 begin
429 then
436 -- The body generated for this renaming is an internal artifact, and
437 -- does not constitute a freeze point for the called entity.
444 declare
448 begin
449 -- The controlling formal may be an access parameter, or the
450 -- actual may be an access value, so adjust accordingly.
454 then
455 Actuals := New_List
460 then
461 Actuals := New_List
465 else
473 else
484 -- If the renamed entity is an entry, inherit its profile. For other
485 -- renamings as bodies, both profiles must be subtype conformant, so it
486 -- is not necessary to replace the profile given in the declaration.
487 -- However, default values that are aggregates are rewritten when
488 -- partially analyzed, so we recover the original aggregate to insure
489 -- that subsequent conformity checking works. Similarly, if the default
490 -- expression was constant-folded, recover the original expression.
500 N_Access_Definition
501 then
509 then
520 -- If the renamed entity is a function, the generated body contains a
521 -- return statement. Otherwise, build a procedure call. If the entity is
522 -- an entry, subsequent analysis of the call will transform it into the
523 -- proper entry or protected operation call. If the renamed entity is
524 -- a character literal, return it directly.
530 then
531 Call_Node :=
533 Expression =>
539 Call_Node :=
544 Call_Node :=
548 else
549 Call_Node :=
555 -- Create entities for subprogram body and formals
568 Body_Node :=
572 Handled_Statement_Sequence =>
582 -- Link the body to the entity whose declaration it completes. If
583 -- the body is analyzed when the renamed entity is frozen, it may
584 -- be necessary to restore the proper scope (see package Exp_Ch13).
588 then
590 else
597 --------------------------
598 -- Check_Address_Clause --
599 --------------------------
610 begin
617 -- Has_Delayed_Freeze was set on E when the address clause was
618 -- analyzed, and must remain set because we want the address
619 -- clause to be elaborated only after any entity it references
620 -- has been elaborated.
623 -- If Rep_Clauses are to be ignored, remove address clause from
624 -- list attached to entity, because it may be illegal for gigi,
625 -- for example by breaking order of elaboration..
628 declare
631 begin
637 else
640 loop
650 -- And now remove the address clause
656 then
662 -- Capture initialization value at point of declaration,
663 -- and make explicit assignment legal, because object may
664 -- be a constant.
670 -- Move initialization to freeze actions (once the object has
671 -- been frozen, and the address clause alignment check has been
672 -- performed.
681 -- If the objet is tagged, check whether the tag must be
682 -- reassigned expliitly.
692 -----------------------------
693 -- Check_Compile_Time_Size --
694 -----------------------------
699 -- Sets the compile time known size (32 bits or less) in the Esize
700 -- field, of T checking for a size clause that was given which attempts
701 -- to give a smaller size, and also checking for an alignment clause.
704 -- Recursive function that does all the work
707 -- If T is a constrained subtype, its size is not known if any of its
708 -- discriminant constraints is not static and it is not a null record.
709 -- The test is conservative and doesn't check that the components are
710 -- in fact constrained by non-static discriminant values. Could be made
711 -- more precise ???
713 --------------------
714 -- Set_Small_Size --
715 --------------------
718 begin
722 -- Check for bad size clause given
727 Error_Msg_NE
732 -- Set size if not set already
739 ----------------
740 -- Size_Known --
741 ----------------
750 begin
754 -- Always True for scalar types. This is true even for generic formal
755 -- scalar types. We used to return False in the latter case, but the
756 -- size is known at compile time, even in the template, we just do
757 -- not know the exact size but that's not the point of this routine.
761 then
764 -- Array types
768 -- String literals always have known size, and we can set it
775 -- Unconstrained types never have known at compile time size
780 -- Don't do any recursion on type with error posted, since we may
781 -- have a malformed type that leads us into a loop.
786 -- Otherwise if component size unknown, then array size unknown
792 -- Check for all indexes static, and also compute possible size
793 -- (in case it is less than 32 and may be packable).
795 declare
799 begin
808 else
816 then
819 else
824 else
836 -- Access types always have known at compile time sizes
841 -- For non-generic private types, go to underlying type if present
846 then
847 -- Don't do any recursion on type with error posted, since we may
848 -- have a malformed type that leads us into a loop.
852 else
856 -- Record types
860 -- A class-wide type is never considered to have a known size
865 -- A subtype of a variant record must not have non-static
866 -- discriminated components.
870 then
873 -- Don't do any recursion on type with error posted, since we may
874 -- have a malformed type that leads us into a loop.
880 -- Now look at the components of the record
882 declare
883 -- The following two variables are used to keep track of the
884 -- size of packed records if we can tell the size of the packed
885 -- record in the front end. Packed_Size_Known is True if so far
886 -- we can figure out the size. It is initialized to True for a
887 -- packed record, unless the record has discriminants or atomic
888 -- components or independent components.
890 -- The reason we eliminate the discriminated case is that
891 -- we don't know the way the back end lays out discriminated
892 -- packed records. If Packed_Size_Known is True, then
893 -- Packed_Size is the size in bits so far.
902 -- Size in bits so far
904 begin
905 -- Test for variant part present
911 N_Record_Definition
913 and then
914 Present (Variant_Part
916 then
917 -- If variant part is present, and type is unconstrained,
918 -- then we must have defaulted discriminants, or a size
919 -- clause must be present for the type, or else the size
920 -- is definitely not known at compile time.
923 and then
926 then
931 -- Loop through components
937 -- We do not know the packed size if there is a component
938 -- clause present (we possibly could, but this would only
939 -- help in the case of a record with partial rep clauses.
940 -- That's because in the case of full rep clauses, the
941 -- size gets figured out anyway by a different circuit).
947 -- We do not know the packed size if we have a by reference
948 -- type, or an atomic type or an atomic component, or an
949 -- aliased component (because packing does not touch these).
955 then
959 -- We need to identify a component that is an array where
960 -- the index type is an enumeration type with non-standard
961 -- representation, and some bound of the type depends on a
962 -- discriminant.
964 -- This is because gigi computes the size by doing a
965 -- substitution of the appropriate discriminant value in
966 -- the size expression for the base type, and gigi is not
967 -- clever enough to evaluate the resulting expression (which
968 -- involves a call to rep_to_pos) at compile time.
970 -- It would be nice if gigi would either recognize that
971 -- this expression can be computed at compile time, or
972 -- alternatively figured out the size from the subtype
973 -- directly, where all the information is at hand ???
977 then
978 declare
986 begin
993 then
999 then
1004 then
1014 -- Clearly size of record is not known if the size of one of
1015 -- the components is not known.
1021 -- Accumulate packed size if possible
1025 -- We can only deal with elementary types, since for
1026 -- non-elementary components, alignment enters into the
1027 -- picture, and we don't know enough to handle proper
1028 -- alignment in this context. Packed arrays count as
1029 -- elementary if the representation is a modular type.
1033 and then Present
1035 and then Is_Modular_Integer_Type
1037 then
1038 -- Packed size unknown if we have an atomic type
1039 -- or a by reference type, since the back end
1040 -- knows how these are layed out.
1044 then
1047 -- If RM_Size is known and static, then we can keep
1048 -- accumulating the packed size
1052 -- A little glitch, to be removed sometime ???
1053 -- gigi does not understand zero sizes yet.
1058 -- Normal case where we can keep accumulating the
1059 -- packed array size.
1061 else
1065 -- If we have a field whose RM_Size is not known then
1066 -- we can't figure out the packed size here.
1068 else
1072 -- If we have a non-elementary type we can't figure out
1073 -- the packed array size (alignment issues).
1075 else
1090 -- All other cases, size not known at compile time
1092 else
1097 -------------------------------------
1098 -- Static_Discriminated_Components --
1099 -------------------------------------
1101 function Static_Discriminated_Components
1103 is
1106 begin
1110 then
1124 -- Start of processing for Check_Compile_Time_Size
1126 begin
1130 -----------------------------------
1131 -- Check_Component_Storage_Order --
1132 -----------------------------------
1134 procedure Check_Component_Storage_Order
1139 is
1145 -- Set for the record case, True if Comp starts on a byte boundary
1146 -- (in which case it is allowed to have different storage order).
1149 -- Set True when the component is a nested composite, and it does not
1150 -- have the same scalar storage order as Encl_Type.
1154 begin
1155 -- Record case
1165 else
1166 -- If a component clause is present, check if the component starts
1167 -- on a storage element boundary. Otherwise conservatively assume
1168 -- it does so only in the case where the record is not packed.
1171 Comp_Byte_Aligned :=
1173 else
1180 -- Array case
1182 else
1189 -- Note: the Reverse_Storage_Order flag is set on the base type, but
1190 -- the attribute definition clause is attached to the first subtype.
1193 Comp_ADC := Get_Attribute_Definition_Clause
1195 Attribute_Scalar_Storage_Order);
1198 -- Case of record or array component: check storage order compatibility
1201 Comp_SSO_Differs :=
1203 /=
1206 -- Parent and extension must have same storage order
1210 Error_Msg_N
1215 -- If enclosing composite has explicit SSO then nested composite must
1216 -- have explicit SSO as well.
1222 -- If component and composite SSO differs, check that component
1223 -- falls on byte boundaries and isn't packed.
1227 -- Component SSO differs from enclosing composite:
1229 -- Reject if component is a packed array, as it may be represented
1230 -- as a scalar internally.
1233 Error_Msg_N
1237 -- Reject if composite is a packed array, as it may be rewritten
1238 -- into an array of scalars.
1244 -- Reject if not byte aligned
1247 and then not Comp_Byte_Aligned
1248 then
1249 Error_Msg_N
1255 -- Enclosing type has explicit SSO: non-composite component must not
1256 -- be aliased.
1259 Error_Msg_N
1265 -----------------------------
1266 -- Check_Debug_Info_Needed --
1267 -----------------------------
1270 begin
1275 or else Debug_Generated_Code
1276 or else Debug_Flag_VV
1278 then
1283 -------------------------------
1284 -- Check_Expression_Function --
1285 -------------------------------
1291 -- Function to search for deferred constant
1293 -------------------
1294 -- Find_Constant --
1295 -------------------
1298 begin
1299 -- When a constant is initialized with the result of a dispatching
1300 -- call, the constant declaration is rewritten as a renaming of the
1301 -- displaced function result. This scenario is not a premature use of
1302 -- a constant even though the Has_Completion flag is not set.
1309 N_Object_Declaration
1312 then
1313 Error_Msg_NE
1321 then
1331 -- Start of processing for Check_Expression_Function
1333 begin
1338 then
1343 ----------------------------
1344 -- Check_Strict_Alignment --
1345 ----------------------------
1350 begin
1368 then
1378 -------------------------
1379 -- Check_Unsigned_Type --
1380 -------------------------
1387 begin
1392 -- Do not attempt to analyze case where range was in error
1398 -- The situation that is non trivial is something like
1400 -- subtype x1 is integer range -10 .. +10;
1401 -- subtype x2 is x1 range 0 .. V1;
1402 -- subtype x3 is x2 range V2 .. V3;
1403 -- subtype x4 is x3 range V4 .. V5;
1405 -- where Vn are variables. Here the base type is signed, but we still
1406 -- know that x4 is unsigned because of the lower bound of x2.
1408 -- The only way to deal with this is to look up the ancestor chain
1411 loop
1425 else
1428 -- If no ancestor had a static lower bound, go to base type
1432 -- Note: the reason we still check for a compile time known
1433 -- value for the base type is that at least in the case of
1434 -- generic formals, we can have bounds that fail this test,
1435 -- and there may be other cases in error situations.
1447 then
1457 -------------------------
1458 -- Is_Atomic_Aggregate --
1459 -------------------------
1461 function Is_Atomic_Aggregate
1464 is
1470 begin
1473 -- Array may be qualified, so find outer context
1481 then
1483 New_N :=
1494 else
1499 -----------------------------------------------
1500 -- Explode_Initialization_Compound_Statement --
1501 -----------------------------------------------
1506 begin
1509 then
1512 -- Note that we rewrite Init_Stmts into a NULL statement, rather than
1513 -- just removing it, because Freeze_All may rely on this particular
1514 -- Node_Id still being present in the enclosing list to know where to
1515 -- stop freezing.
1523 ----------------
1524 -- Freeze_All --
1525 ----------------
1527 -- Note: the easy coding for this procedure would be to just build a
1528 -- single list of freeze nodes and then insert them and analyze them
1529 -- all at once. This won't work, because the analysis of earlier freeze
1530 -- nodes may recursively freeze types which would otherwise appear later
1531 -- on in the freeze list. So we must analyze and expand the freeze nodes
1532 -- as they are generated.
1539 -- This is the internal recursive routine that does freezing of entities
1540 -- (but NOT the analysis of default expressions, which should not be
1541 -- recursive, we don't want to analyze those till we are sure that ALL
1542 -- the types are frozen).
1544 --------------------
1545 -- Freeze_All_Ent --
1546 --------------------
1554 -- If freeze nodes are present, insert and analyze, and reset cursor
1555 -- for next insertion.
1557 -------------------
1558 -- Process_Flist --
1559 -------------------
1562 begin
1569 else
1575 -- Start or processing for Freeze_All_Ent
1577 begin
1581 -- If the entity is an inner package which is not a package
1582 -- renaming, then its entities must be frozen at this point. Note
1583 -- that such entities do NOT get frozen at the end of the nested
1584 -- package itself (only library packages freeze).
1586 -- Same is true for task declarations, where anonymous records
1587 -- created for entry parameters must be frozen.
1593 then
1604 then
1611 N_Single_Task_Declaration)
1612 then
1615 End_Scope;
1617 -- For a derived tagged type, we must ensure that all the
1618 -- primitive operations of the parent have been frozen, so that
1619 -- their addresses will be in the parent's dispatch table at the
1620 -- point it is inherited.
1626 then
1627 declare
1634 begin
1641 then
1643 Process_Flist;
1653 Process_Flist;
1655 -- If already frozen, and there are delayed aspects, this is where
1656 -- we do the visibility check for these aspects (see Sem_Ch13 spec
1657 -- for a description of how we handle aspect visibility).
1661 -- Retrieve the visibility to the discriminants in order to
1662 -- analyze properly the aspects.
1666 declare
1669 begin
1675 then
1686 -- If an incomplete type is still not frozen, this may be a
1687 -- premature freezing because of a body declaration that follows.
1688 -- Indicate where the freezing took place. Freezing will happen
1689 -- if the body comes from source, but not if it is internally
1690 -- generated, for example as the body of a type invariant.
1692 -- If the freezing is caused by the end of the current declarative
1693 -- part, it is a Taft Amendment type, and there is no error.
1697 then
1698 declare
1701 begin
1702 -- The presence of a body freezes all entities previously
1703 -- declared in the current list of declarations, but this
1704 -- does not apply if the body does not come from source.
1705 -- A type invariant is transformed into a subprogram body
1706 -- which is placed at the end of the private part of the
1707 -- current package, but this body does not freeze incomplete
1708 -- types that may be declared in this private part.
1711 N_Entry_Body,
1712 N_Package_Body,
1713 N_Protected_Body,
1714 N_Task_Body)
1716 and then
1719 then
1721 Error_Msg_NE
1732 -- Start of processing for Freeze_All
1734 begin
1737 -- Now that all types are frozen, we can deal with default expressions
1738 -- that require us to build a default expression functions. This is the
1739 -- point at which such functions are constructed (after all types that
1740 -- might be used in such expressions have been frozen).
1742 -- For subprograms that are renaming_as_body, we create the wrapper
1743 -- bodies as needed.
1745 -- We also add finalization chains to access types whose designated
1746 -- types are controlled. This is normally done when freezing the type,
1747 -- but this misses recursive type definitions where the later members
1748 -- of the recursion introduce controlled components.
1750 -- Loop through entities
1765 else
1771 and then
1773 = N_Subprogram_Renaming_Declaration
1774 then
1775 Build_And_Analyze_Renamed_Body
1782 N_Single_Task_Declaration)
1783 then
1784 declare
1787 begin
1792 then
1800 -- We add finalization masters to access types whose designated types
1801 -- require finalization. This is normally done when freezing the
1802 -- type, but this misses recursive type definitions where the later
1803 -- members of the recursion introduce controlled components (such as
1804 -- can happen when incomplete types are involved), as well cases
1805 -- where a component type is private and the controlled full type
1806 -- occurs after the access type is frozen. Cases that don't need a
1807 -- finalization master are generic formal types (the actual type will
1808 -- have it) and types derived from them, and types with Java and CIL
1809 -- conventions, since those are used for API bindings.
1810 -- (Are there any other cases that should be excluded here???)
1816 then
1824 -----------------------
1825 -- Freeze_And_Append --
1826 -----------------------
1828 procedure Freeze_And_Append
1832 is
1834 begin
1838 else
1844 -------------------
1845 -- Freeze_Before --
1846 -------------------
1851 begin
1861 -------------------
1862 -- Freeze_Entity --
1863 -------------------
1867 -- Save the current Ghost mode in effect in case the entity being frozen
1868 -- sets a different mode.
1878 -- This could use a comment ???
1881 -- Used to detect attempt to freeze function declared in another unit
1884 -- List of freezing actions, left at No_List if none
1887 -- This flag gets set to true for a variable with default initialization
1890 -- N is a freezing action to be appended to the Result
1893 -- If Loc is a freeze_entity that appears after the last declaration
1894 -- in the scope, inhibit error messages on late completion.
1897 -- Check that an Access or Unchecked_Access attribute with a prefix
1898 -- which is the current instance type can only be applied when the type
1899 -- is limited.
1902 -- Give warning for modulus of 8, 16, 32, or 64 given as an explicit
1903 -- integer literal without an explicit corresponding size clause. The
1904 -- caller has checked that Utype is a modular integer type.
1907 -- Freeze array type, including freezing index and component types
1910 -- Create Freeze_Generic_Entity nodes for types declared in a generic
1911 -- package. Recurse on inner generic packages.
1914 -- Freeze formals and return type of subprogram. If some type in the
1915 -- profile is a limited view, freezing of the entity will take place
1916 -- elsewhere, and the function returns False. This routine will be
1917 -- modified if and when we can implement AI05-019 efficiently ???
1920 -- Freeze record type, including freezing component types, and freezing
1921 -- primitive operations if this is a tagged type.
1924 -- Determine whether an arbitrary entity is subject to Boolean aspect
1925 -- Import and its value is specified as True.
1928 -- Following AI05-151, a function can return a limited view of a type
1929 -- declared elsewhere. In that case the function cannot be frozen at
1930 -- the end of its enclosing package. If its first use is in a different
1931 -- unit, it cannot be frozen there, but if the call is legal the full
1932 -- view of the return type is available and the subprogram can now be
1933 -- frozen. However the freeze node cannot be inserted at the point of
1934 -- call, but rather must go in the package holding the function, so that
1935 -- the backend can process it in the proper context.
1938 -- Restore the values of all saved global variables
1941 -- If E is an entity for an imported subprogram with pre/post-conditions
1942 -- then this procedure will create a wrapper to ensure that proper run-
1943 -- time checking of the pre/postconditions. See body for details.
1945 -------------------
1946 -- Add_To_Result --
1947 -------------------
1950 begin
1953 else
1958 ----------------------------
1959 -- After_Last_Declaration --
1960 ----------------------------
1965 begin
1971 else
1975 else
1980 ----------------------------
1981 -- Check_Current_Instance --
1982 ----------------------------
1987 -- Determine whether Typ is compatible with the rules for aliased
1988 -- views of types as defined in RM 3.10 in the various dialects.
1991 -- Process routine to apply check to given node
1993 -----------------------------
1994 -- Is_Aliased_View_Of_Type --
1995 -----------------------------
2000 begin
2001 -- Common case
2005 then
2008 -- The following paragraphs describe what a legal aliased view of
2009 -- a type is in the various dialects of Ada.
2011 -- Ada 95
2013 -- The current instance of a limited type, and a formal parameter
2014 -- or generic formal object of a tagged type.
2016 -- Ada 95 limited type
2017 -- * Type with reserved word "limited"
2018 -- * A protected or task type
2019 -- * A composite type with limited component
2024 -- Ada 2005
2026 -- The current instance of a limited tagged type, a protected
2027 -- type, a task type, or a type that has the reserved word
2028 -- "limited" in its full definition ... a formal parameter or
2029 -- generic formal object of a tagged type.
2031 -- Ada 2005 limited type
2032 -- * Type with reserved word "limited", "synchronized", "task"
2033 -- or "protected"
2034 -- * A composite type with limited component
2035 -- * A derived type whose parent is a non-interface limited type
2038 return
2040 or else
2045 -- Ada 2012 and beyond
2047 -- The current instance of an immutably limited type ... a formal
2048 -- parameter or generic formal object of a tagged type.
2050 -- Ada 2012 limited type
2051 -- * Type with reserved word "limited", "synchronized", "task"
2052 -- or "protected"
2053 -- * A composite type with limited component
2054 -- * A derived type whose parent is a non-interface limited type
2055 -- * An incomplete view
2057 -- Ada 2012 immutably limited type
2058 -- * Explicitly limited record type
2059 -- * Record extension with "limited" present
2060 -- * Non-formal limited private type that is either tagged
2061 -- or has at least one access discriminant with a default
2062 -- expression
2063 -- * Task type, protected type or synchronized interface
2064 -- * Type derived from immutably limited type
2066 else
2067 return
2073 -------------
2074 -- Process --
2075 -------------
2078 begin
2082 Name_Unchecked_Access)
2086 then
2088 Error_Msg_N
2091 else
2092 Error_Msg_N
2099 else
2109 -- Local variables
2114 -- Start of processing for Check_Current_Instance
2116 begin
2122 ------------------------------
2123 -- Check_Suspicious_Modulus --
2124 ------------------------------
2129 begin
2135 declare
2138 begin
2140 declare
2144 begin
2146 declare
2150 begin
2151 -- First case, modulus and size are the same. This
2152 -- happens if you have something like mod 32, with
2153 -- an explicit size of 32, this is for sure a case
2154 -- where the warning is given, since it is seems
2155 -- very unlikely that someone would want e.g. a
2156 -- five bit type stored in 32 bits. It is much
2157 -- more likely they wanted a 32-bit type.
2162 -- Second case, the modulus is 32 or 64 and no
2163 -- size clause is present. This is a less clear
2164 -- case for giving the warning, but in the case
2165 -- of 32/64 (5-bit or 6-bit types) these seem rare
2166 -- enough that it is a likely error (and in any
2167 -- case using 2**5 or 2**6 in these cases seems
2168 -- clearer. We don't include 8 or 16 here, simply
2169 -- because in practice 3-bit and 4-bit types are
2170 -- more common and too many false positives if
2171 -- we warn in these cases.
2175 then
2178 -- No warning needed
2180 else
2184 -- If we fall through, give warning
2187 Error_Msg_N
2189 Modulus);
2198 -----------------------
2199 -- Freeze_Array_Type --
2200 -----------------------
2208 -- Set true if any of the index types is an enumeration type with a
2209 -- non-standard representation.
2211 begin
2220 then
2227 -- Processing that is done only for base types
2231 -- Deal with default setting of reverse storage order
2235 -- Propagate flags for component type
2239 then
2247 -- Warn for pragma Pack overriding foreign convention
2251 then
2252 declare
2257 begin
2261 Error_Msg_N
2264 Error_Msg_N
2271 -- If packing was requested or if the component size was
2272 -- set explicitly, then see if bit packing is required. This
2273 -- processing is only done for base types, since all of the
2274 -- representation aspects involved are type-related.
2276 -- This is not just an optimization, if we start processing the
2277 -- subtypes, they interfere with the settings on the base type
2278 -- (this is because Is_Packed has a slightly different meaning
2279 -- before and after freezing).
2281 declare
2285 begin
2289 then
2298 else
2301 -- We can set the component size if it is less than 16,
2302 -- rounding it up to the next storage unit size.
2308 else
2312 -- Set component size up to match alignment if it would
2313 -- otherwise be less than the alignment. This deals with
2314 -- cases of types whose alignment exceeds their size (the
2315 -- padded type cases).
2318 declare
2320 begin
2328 -- Case of component size that may result in packing
2331 declare
2337 Get_Attribute_Definition_Clause
2340 begin
2341 -- Warn if we have pack and component size so that the
2342 -- pack is ignored.
2344 -- Note: here we must check for the presence of a
2345 -- component size before checking for a Pack pragma to
2346 -- deal with the case where the array type is a derived
2347 -- type whose parent is currently private.
2351 and then Warn_On_Redundant_Constructs
2352 then
2354 Error_Msg_NE
2356 Error_Msg_N
2362 -- Set component size if not already set by a component
2363 -- size clause.
2369 -- Check for base type of 8, 16, 32 bits, where an
2370 -- unsigned subtype has a length one less than the
2371 -- base type (e.g. Natural subtype of Integer).
2373 -- In such cases, if a component size was not set
2374 -- explicitly, then generate a warning.
2380 then
2384 Error_Msg_N
2386 Pack_Pragma);
2387 Error_Msg_N
2389 Pack_Pragma);
2393 -- Actual packing is not needed for 8, 16, 32, 64. Also
2394 -- not needed for 24 if alignment is 1.
2401 then
2402 -- Here the array was requested to be packed, but
2403 -- the packing request had no effect, so Is_Packed
2404 -- is reset.
2406 -- Note: semantically this means that we lose track
2407 -- of the fact that a derived type inherited a pragma
2408 -- Pack that was non- effective, but that seems fine.
2410 -- We regard a Pack pragma as a request to set a
2411 -- representation characteristic, and this request
2412 -- may be ignored.
2419 then
2423 -- In all other cases, packing is indeed needed
2425 else
2434 -- Check for Aliased or Atomic_Components/Atomic with unsuitable
2435 -- packing or explicit component size clause given.
2440 and then
2442 then
2446 -- Outputs error messages for incorrect CS clause or pragma
2447 -- Pack for aliased or atomic components (T is "aliased" or
2448 -- "atomic");
2450 -----------------
2451 -- Complain_CS --
2452 -----------------
2455 begin
2457 Clause :=
2458 Get_Attribute_Definition_Clause
2461 Error_Msg_N
2465 Error_Msg_N
2468 else
2469 Error_Msg_N
2475 -- Start of processing for Alias_Atomic_Check
2477 begin
2478 -- If object size of component type isn't known, we cannot
2479 -- be sure so we defer to the back end.
2484 -- Case where component size has no effect. First check for
2485 -- object size of component type multiple of the storage
2486 -- unit size.
2490 -- OK in both packing case and component size case if RM
2491 -- size is known and static and same as the object size.
2493 and then
2497 -- Or if we have an explicit component size clause and
2498 -- the component size and object size are equal.
2500 or else
2503 then
2510 then
2516 -- Warn for case of atomic type
2522 then
2523 Error_Msg_NE
2538 -- Check for scalar storage order
2540 declare
2542 begin
2543 Check_Component_Storage_Order
2546 ADC => Get_Attribute_Definition_Clause
2548 Attribute_Scalar_Storage_Order),
2552 -- Processing that is done only for subtypes
2554 else
2555 -- Acquire alignment from base type
2563 -- Specific checks for bit-packed arrays
2567 -- Check number of elements for bit packed arrays that come from
2568 -- source and have compile time known ranges. The bit-packed
2569 -- arrays circuitry does not support arrays with more than
2570 -- Integer'Last + 1 elements, and when this restriction is
2571 -- violated, causes incorrect data access.
2573 -- For the case where this is not compile time known, a run-time
2574 -- check should be generated???
2577 declare
2583 begin
2589 -- Never generate an error if any index is of a generic
2590 -- type. We will check this in instances.
2597 Ilen :=
2603 -- No attempt is made to check number of elements if not
2604 -- compile time known.
2617 then
2618 Error_Msg_N
2625 -- Check size
2628 declare
2632 begin
2633 -- It is not clear if it is possible to have no size clause
2634 -- at this stage, but it is not worth worrying about. Post
2635 -- error on the entity name in the size clause if present,
2636 -- else on the type entity itself.
2640 else
2647 -- If any of the index types was an enumeration type with a non-
2648 -- standard rep clause, then we indicate that the array type is
2649 -- always packed (even if it is not bit packed).
2658 -- If the array is packed, we must create the packed array type to be
2659 -- used to actually implement the type. This is only needed for real
2660 -- array types (not for string literal types, since they are present
2661 -- only for the front end).
2665 then
2669 -- Make sure that we have the necessary routines to implement the
2670 -- packing, and complain now if not. Note that we only test this
2671 -- for constrained array types.
2677 then
2678 declare
2682 begin
2685 then
2686 Error_Msg_CRT
2690 -- Cancel the packing
2700 -- Size information of packed array type is copied to the array
2701 -- type, since this is really the representation. But do not
2702 -- override explicit existing size values. If the ancestor subtype
2703 -- is constrained the Packed_Array_Impl_Type will be inherited
2704 -- from it, but the size may have been provided already, and
2705 -- must not be overridden either.
2708 and then
2711 then
2723 -- For non-packed arrays set the alignment of the array to the
2724 -- alignment of the component type if it is unknown. Skip this
2725 -- in atomic case (atomic arrays may need larger alignments).
2734 then
2739 -----------------------------
2740 -- Freeze_Generic_Entities --
2741 -----------------------------
2748 begin
2767 --------------------
2768 -- Freeze_Profile --
2769 --------------------
2776 begin
2777 -- Loop through formals
2783 -- AI05-0151: incomplete types can appear in a profile. By the
2784 -- time the entity is frozen, the full view must be available,
2785 -- unless it is a limited view.
2790 then
2802 then
2803 -- If the type of a formal is incomplete, subprogram is being
2804 -- frozen prematurely. Within an instance (but not within a
2805 -- wrapper package) this is an artifact of our need to regard
2806 -- the end of an instantiation as a freeze point. Otherwise it
2807 -- is a definite error.
2814 elsif not After_Last_Declaration
2815 and then not Freezing_Library_Level_Tagged_Type
2816 then
2818 Error_Msg
2823 -- Check suspicious parameter for C function. These tests apply
2824 -- only to exported/imported subprograms.
2826 if Warn_On_Export_Import
2829 or else
2836 then
2837 -- Qualify mention of formals with subprogram name
2841 -- Check suspicious use of fat C pointer
2845 then
2846 Error_Msg_N
2849 -- Check suspicious return of boolean
2856 then
2857 Error_Msg_N
2859 Error_Msg_N
2863 -- Check suspicious tagged type
2866 or else
2870 then
2871 Error_Msg_N
2875 -- Check wrong convention subprogram pointer
2879 then
2880 Error_Msg_N
2884 Error_Msg_NE
2889 -- Turn off name qualification after message output
2894 -- Check for unconstrained array in exported foreign convention
2895 -- case.
2901 and then Warn_On_Export_Import
2903 -- Exclude VM case, since both .NET and JVM can handle
2904 -- unconstrained arrays without a problem.
2907 then
2910 -- If this is an inherited operation, place the warning on
2911 -- the derived type declaration, rather than on the original
2912 -- subprogram.
2915 then
2921 else
2937 -- If the formal is an anonymous_access_to_subprogram
2938 -- freeze the subprogram type as well, to prevent
2939 -- scope anomalies in gigi, because there is no other
2940 -- clear point at which it could be frozen.
2944 then
2952 -- Case of function: similar checks on return type
2956 -- Check whether function is declared elsewhere.
2958 Late_Freezing :=
2963 -- Freeze return type
2967 -- AI05-0151: the return type may have been incomplete
2968 -- at the point of declaration. Replace it with the full
2969 -- view, unless the current type is a limited view. In
2970 -- that case the full view is in a different unit, and
2971 -- gigi finds the non-limited view after the other unit
2972 -- is elaborated.
2977 then
2981 -- If the return type is a limited view and the non-
2982 -- limited view is still incomplete, the function has
2983 -- to be frozen at a later time.
2987 and then
2989 then
2997 -- Check suspicious return type for C function
2999 if Warn_On_Export_Import
3001 or else
3004 then
3005 -- Check suspicious return of fat C pointer
3011 then
3015 -- Check suspicious return of boolean
3023 then
3024 declare
3027 begin
3028 Error_Msg_NE
3030 Error_Msg_NE
3035 -- Check suspicious return tagged type
3039 and then
3040 Is_Tagged_Type
3045 then
3049 -- Check return of wrong convention subprogram pointer
3055 then
3059 Error_Msg_NE
3065 -- Give warning for suspicious return of a result of an
3066 -- unconstrained array type in a foreign convention function.
3070 -- We are looking for a return of unconstrained array
3075 -- Exclude imported routines, the warning does not belong on
3076 -- the import, but rather on the routine definition.
3080 -- Exclude VM case, since both .NET and JVM can handle return
3081 -- of unconstrained arrays without a problem.
3085 -- Check that general warning is enabled, and that it is not
3086 -- suppressed for this particular case.
3088 and then Warn_On_Export_Import
3091 then
3100 ------------------------
3101 -- Freeze_Record_Type --
3102 ------------------------
3114 -- Set True if the record type scope Rec has been pushed on the scope
3115 -- stack. Needed for the analysis of delayed aspects specified to the
3116 -- components of Rec.
3119 -- Scalar_Storage_Order attribute definition clause for the record
3122 -- Set True if we find at least one component with no component
3123 -- clause (used to warn about useless Pack pragmas).
3126 -- Set True if we find at least one component with a component
3127 -- clause (used to warn about useless Bit_Order pragmas, and also
3128 -- to detect cases where Implicit_Packing may have an effect).
3131 -- Set True if we find at least one component which is aliased. This
3132 -- is used to prevent Implicit_Packing of the record, since packing
3133 -- cannot modify the size of alignment of an aliased component.
3136 -- Set True if we find at least one component whose type has a
3137 -- Scalar_Storage_Order attribute definition clause.
3140 -- Set False if we encounter a component of a non-scalar type
3144 -- Accumulates total RM_Size values and total Esize values of all
3145 -- scalar components. Used for processing of Implicit_Packing.
3148 -- If N is an allocator, possibly wrapped in one or more level of
3149 -- qualified expression(s), return the inner allocator node, else
3150 -- return Empty.
3153 -- If the component subtype is an access to a constrained subtype of
3154 -- an already frozen type, make the subtype frozen as well. It might
3155 -- otherwise be frozen in the wrong scope, and a freeze node on
3156 -- subtype has no effect. Similarly, if the component subtype is a
3157 -- regular (not protected) access to subprogram, set the anonymous
3158 -- subprogram type to frozen as well, to prevent an out-of-scope
3159 -- freeze node at some eventual point of call. Protected operations
3160 -- are handled elsewhere.
3163 -- Make sure that all types mentioned in Discrete_Choices of the
3164 -- variants referenceed by the Variant_Part VP are frozen. This is
3165 -- a recursive routine to deal with nested variants.
3167 ---------------------
3168 -- Check_Allocator --
3169 ---------------------
3173 begin
3175 loop
3180 else
3186 -----------------
3187 -- Check_Itype --
3188 -----------------
3193 begin
3196 then
3199 -- In addition, add an Itype_Reference to ensure that the
3200 -- access subtype is elaborated early enough. This cannot be
3201 -- done if the subtype may depend on discriminants.
3206 then
3214 then
3219 ------------------------------------
3220 -- Freeze_Choices_In_Variant_Part --
3221 ------------------------------------
3230 begin
3231 -- Loop through variants
3236 -- Loop through choices, checking that all types are frozen
3242 then
3249 -- Check for nested variant part to process
3263 -- Start of processing for Freeze_Record_Type
3265 begin
3266 -- Deal with delayed aspect specifications for components. The
3267 -- analysis of the aspect is required to be delayed to the freeze
3268 -- point, thus we analyze the pragma or attribute definition
3269 -- clause in the tree at this point. We also analyze the aspect
3270 -- specification node at the freeze point when the aspect doesn't
3271 -- correspond to pragma/attribute definition clause.
3277 then
3282 -- The visibility to the discriminants must be restored in
3283 -- order to properly analyze the aspects.
3296 -- Pop the scope if Rec scope has been pushed on the scope stack
3297 -- during the delayed aspect analysis process.
3304 Pop_Scope;
3307 -- Freeze components and embedded subtypes
3316 -- Handle the component and discriminant case
3319 declare
3322 begin
3323 -- Freezing a record type freezes the type of each of its
3324 -- components. However, if the type of the component is
3325 -- part of this record, we do not want or need a separate
3326 -- Freeze_Node. Note that Is_Itype is wrong because that's
3327 -- also set in private type cases. We also can't check for
3328 -- the Scope being exactly Rec because of private types and
3329 -- record extensions.
3334 then
3340 -- Warn for pragma Pack overriding foreign convention
3345 -- Don't warn for aliased components, since override
3346 -- cannot happen in that case.
3349 then
3350 declare
3355 begin
3359 Error_Msg_N
3361 PP);
3363 Error_Msg_NE
3370 -- Check for error of component clause given for variable
3371 -- sized type. We have to delay this test till this point,
3372 -- since the component type has to be frozen for us to know
3373 -- if it is variable length.
3378 -- We omit this test in a generic context, it will be
3379 -- applied at instantiation time.
3384 -- Also omit this test in CodePeer mode, since we do not
3385 -- have sufficient info on size and rep clauses.
3390 -- Omit check if component has a generic type. This can
3391 -- happen in an instantiation within a generic in ASIS
3392 -- mode, where we force freeze actions without full
3393 -- expansion.
3398 -- Do the check
3400 elsif not
3401 Size_Known_At_Compile_Time
3403 then
3404 Error_Msg_N
3409 else
3413 -- Case of component requires byte alignment
3417 -- Set the enclosing record to also require byte align
3421 -- Check for component clause that is inconsistent with
3422 -- the required byte boundary alignment.
3427 then
3428 Error_Msg_N
3436 -- Gather data for possible Implicit_Packing later. Note that at
3437 -- this stage we might be dealing with a real component, or with
3438 -- an implicit subtype declaration.
3442 else
3443 Scalar_Component_Total_RM_Size :=
3445 Scalar_Component_Total_Esize :=
3449 -- If the component is an Itype with Delayed_Freeze and is either
3450 -- a record or array subtype and its base type has not yet been
3451 -- frozen, we must remove this from the entity list of this record
3452 -- and put it on the entity list of the scope of its base type.
3453 -- Note that we know that this is not the type of a component
3454 -- since we cleared Has_Delayed_Freeze for it in the previous
3455 -- loop. Thus this must be the Designated_Type of an access type,
3456 -- which is the type of a component.
3464 then
3465 declare
3469 begin
3470 -- We have a difficult case to handle here. Suppose Rec is
3471 -- subtype being defined in a subprogram that's created as
3472 -- part of the freezing of Rec'Base. In that case, we know
3473 -- that Comp'Base must have already been frozen by the time
3474 -- we get to elaborate this because Gigi doesn't elaborate
3475 -- any bodies until it has elaborated all of the declarative
3476 -- part. But Is_Frozen will not be set at this point because
3477 -- we are processing code in lexical order.
3479 -- We detect this case by going up the Scope chain of Rec
3480 -- and seeing if we have a subprogram scope before reaching
3481 -- the top of the scope chain or that of Comp'Base. If we
3482 -- do, then mark that Comp'Base will actually be frozen. If
3483 -- so, we merely undelay it.
3500 else
3503 else
3507 -- Insert in entity list of scope of base type (which
3508 -- must be an enclosing scope, because still unfrozen).
3514 -- If the component is an access type with an allocator as default
3515 -- value, the designated type will be frozen by the corresponding
3516 -- expression in init_proc. In order to place the freeze node for
3517 -- the designated type before that for the current record type,
3518 -- freeze it now.
3520 -- Same process if the component is an array of access types,
3521 -- initialized with an aggregate. If the designated type is
3522 -- private, it cannot contain allocators, and it is premature
3523 -- to freeze the type, so we check for this as well.
3528 then
3529 declare
3533 begin
3536 -- If component is pointer to a class-wide type, freeze
3537 -- the specific type in the expression being allocated.
3538 -- The expression may be a subtype indication, in which
3539 -- case freeze the subtype mark.
3541 if Is_Class_Wide_Type
3543 then
3545 Freeze_And_Append
3549 then
3550 Freeze_And_Append
3558 else
3559 Freeze_And_Append
3567 then
3570 -- Freeze the designated type when initializing a component with
3571 -- an aggregate in case the aggregate contains allocators.
3573 -- type T is ...;
3574 -- type T_Ptr is access all T;
3575 -- type T_Array is array ... of T_Ptr;
3577 -- type Rec is record
3578 -- Comp : T_Array := (others => ...);
3579 -- end record;
3583 then
3584 declare
3587 Designated_Type
3590 begin
3591 -- The only case when this sort of freezing is not done is
3592 -- when the designated type is class-wide and the root type
3593 -- is the record owning the component. This scenario results
3594 -- in a circularity because the class-wide type requires
3595 -- primitives that have not been created yet as the root
3596 -- type is in the process of being frozen.
3598 -- type Rec is tagged;
3599 -- type Rec_Ptr is access all Rec'Class;
3600 -- type Rec_Array is array ... of Rec_Ptr;
3602 -- type Rec is record
3603 -- Comp : Rec_Array := (others => ...);
3604 -- end record;
3608 then
3616 then
3626 -- Deal with default setting of reverse storage order
3630 -- Check consistent attribute setting on component types
3632 SSO_ADC := Get_Attribute_Definition_Clause
3635 declare
3637 begin
3640 Check_Component_Storage_Order
3650 -- Now deal with reverse storage order/bit order issues
3654 -- Check compatibility of Scalar_Storage_Order with Bit_Order, if
3655 -- the former is specified.
3659 -- Note: report error on Rec, not on SSO_ADC, as ADC may apply
3660 -- to some ancestor type.
3663 Error_Msg_N
3668 -- Warn if there is an Scalar_Storage_Order attribute definition
3669 -- clause but no component clause, no component that itself has
3670 -- such an attribute definition, and no pragma Pack.
3673 or else
3674 SSO_ADC_Component
3675 or else
3677 then
3678 Error_Msg_N
3680 SSO_ADC);
3684 -- Deal with Bit_Order aspect
3692 then
3693 -- Warn if clause has no effect when no component clause is
3694 -- present, but suppress warning if the Bit_Order is required
3695 -- due to the presence of a Scalar_Storage_Order attribute.
3697 Error_Msg_N
3699 Error_Msg_N
3702 -- Here is where we do the processing to adjust component clauses
3703 -- for reversed bit order, when not using reverse SSO.
3707 then
3710 -- Case where we have both an explicit Bit_Order and the same
3711 -- Scalar_Storage_Order: leave record untouched, the back-end
3712 -- will take care of required layout conversions.
3714 else
3720 -- Complete error checking on record representation clause (e.g.
3721 -- overlap of components). This is called after adjusting the
3722 -- record for reverse bit order.
3724 declare
3726 begin
3732 -- Set OK_To_Reorder_Components depending on debug flags
3736 or else
3738 then
3743 -- Check for useless pragma Pack when all components placed. We only
3744 -- do this check for record types, not subtypes, since a subtype may
3745 -- have all its components placed, and it still makes perfectly good
3746 -- sense to pack other subtypes or the parent type. We do not give
3747 -- this warning if Optimize_Alignment is set to Space, since the
3748 -- pragma Pack does have an effect in this case (it always resets
3749 -- the alignment to one).
3753 and then not Unplaced_Component
3755 then
3756 -- Reset packed status. Probably not necessary, but we do it so
3757 -- that there is no chance of the back end doing something strange
3758 -- with this redundant indication of packing.
3762 -- Give warning if redundant constructs warnings on
3765 Error_Msg_N -- CODEFIX
3771 -- If this is the record corresponding to a remote type, freeze the
3772 -- remote type here since that is what we are semantically freezing.
3773 -- This prevents the freeze node for that type in an inner scope.
3780 -- Check for controlled components and unchecked unions.
3785 -- Do not set Has_Controlled_Component on a class-wide
3786 -- equivalent type. See Make_CW_Equivalent_Type.
3789 and then
3791 or else
3794 or else
3796 and then
3798 and then
3799 Has_Controlled_Component
3801 then
3809 -- Scan component declaration for likely misuses of current
3810 -- instance, either in a constraint or a default expression.
3820 -- Enforce the restriction that access attributes with a current
3821 -- instance prefix can only apply to limited types. This comment
3822 -- is floating here, but does not seem to belong here???
3824 -- Set component alignment if not otherwise already set
3828 -- For first subtypes, check if there are any fixed-point fields with
3829 -- component clauses, where we must check the size. This is not done
3830 -- till the freeze point since for fixed-point types, we do not know
3831 -- the size until the type is frozen. Similar processing applies to
3832 -- bit packed arrays.
3840 then
3841 Check_Size
3845 Junk);
3852 -- Generate warning for applying C or C++ convention to a record
3853 -- with discriminants. This is suppressed for the unchecked union
3854 -- case, since the whole point in this case is interface C. We also
3855 -- do not generate this within instantiations, since we will have
3856 -- generated a message on the template.
3861 or else
3864 and then not In_Instance
3867 then
3868 declare
3872 begin
3877 Error_Msg_N
3879 A2);
3880 else
3881 Error_Msg_N
3883 A2);
3886 Error_Msg_NE
3892 -- See if Size is too small as is (and implicit packing might help)
3896 -- No implicit packing if even one component is explicitly placed
3898 and then not Placed_Component
3900 -- Or even one component is aliased
3902 and then not Aliased_Component
3904 -- Must have size clause and all scalar components
3907 and then All_Scalar_Components
3909 -- Do not try implicit packing on records with discriminants, too
3910 -- complicated, especially in the variant record case.
3914 -- We can implicitly pack if the specified size of the record is
3915 -- less than the sum of the object sizes (no point in packing if
3916 -- this is not the case).
3920 -- And the total RM size cannot be greater than the specified size
3921 -- since otherwise packing will not get us where we have to be.
3925 -- Never do implicit packing in CodePeer or SPARK modes since
3926 -- we don't do any packing in these modes, since this generates
3927 -- over-complex code that confuses static analysis, and in
3928 -- general, neither CodePeer not GNATprove care about the
3929 -- internal representation of objects.
3932 then
3933 -- If implicit packing enabled, do it
3938 -- Otherwise flag the size clause
3940 else
3941 declare
3943 begin
3944 Error_Msg_NE -- CODEFIX
3946 Error_Msg_N -- CODEFIX
3953 -- The following checks are only relevant when SPARK_Mode is on as
3954 -- they are not standard Ada legality rules.
3959 -- A discriminated type cannot be effectively volatile
3960 -- (SPARK RM C.6(4)).
3965 -- A tagged type cannot be effectively volatile
3966 -- (SPARK RM C.6(5)).
3972 -- A non-effectively volatile record type cannot contain
3973 -- effectively volatile components (SPARK RM C.6(2)).
3975 else
3980 then
3982 Error_Msg_N
3992 -- All done if not a full record definition
3998 -- Finally we need to check the variant part to make sure that
3999 -- all types within choices are properly frozen as part of the
4000 -- freezing of the record type.
4007 begin
4008 -- Find component list
4020 then
4025 -- Case of variant part present
4031 -- Note: we used to call Check_Choices here, but it is too early,
4032 -- since predicated subtypes are frozen here, but their freezing
4033 -- actions are in Analyze_Freeze_Entity, which has not been called
4034 -- yet for entities frozen within this procedure, so we moved that
4035 -- call to the Analyze_Freeze_Entity for the record type.
4039 -- Check that all the primitives of an interface type are abstract
4040 -- or null procedures.
4044 then
4045 declare
4049 begin
4056 -- Avoid reporting the error on inherited primitives
4059 then
4064 Error_Msg_N
4068 else
4069 Error_Msg_N
4081 -------------------------------
4082 -- Has_Boolean_Aspect_Import --
4083 -------------------------------
4090 begin
4096 -- The value of aspect Import is True when the expression is
4097 -- either missing or it is explicitly set to True.
4103 then
4114 ----------------------------
4115 -- Late_Freeze_Subprogram --
4116 ----------------------------
4123 begin
4126 else
4133 ---------------------
4134 -- Restore_Globals --
4135 ---------------------
4138 begin
4142 ------------------------------
4143 -- Wrap_Imported_Subprogram --
4144 ------------------------------
4146 -- The issue here is that our normal approach of checking preconditions
4147 -- and postconditions does not work for imported procedures, since we
4148 -- are not generating code for the body. To get around this we create
4149 -- a wrapper, as shown by the following example:
4151 -- procedure K (A : Integer);
4152 -- pragma Import (C, K);
4154 -- The spec is rewritten by removing the effects of pragma Import, but
4155 -- leaving the convention unchanged, as though the source had said:
4157 -- procedure K (A : Integer);
4158 -- pragma Convention (C, K);
4160 -- and we create a body, added to the entity K freeze actions, which
4161 -- looks like:
4163 -- procedure K (A : Integer) is
4164 -- procedure K (A : Integer);
4165 -- pragma Import (C, K);
4166 -- begin
4167 -- K (A);
4168 -- end K;
4170 -- Now the contract applies in the normal way to the outer procedure,
4171 -- and the inner procedure has no contracts, so there is no problem
4172 -- in just calling it to get the original effect.
4174 -- In the case of a function, we create an appropriate return statement
4175 -- for the subprogram body that calls the inner procedure.
4187 begin
4188 -- Nothing to do if not imported
4193 -- Test enabling conditions for wrapping
4198 and then not GNATprove_Mode
4199 then
4200 -- Here we do the wrap
4202 -- Note on calls to Copy_Separate_Tree. The trees we are copying
4203 -- here are fully analyzed, but we definitely want fully syntactic
4204 -- unanalyzed trees in the body we construct, so that the analysis
4205 -- generates the right visibility, and that is exactly what the
4206 -- calls to Copy_Separate_Tree give us.
4208 -- Acquire copy of Inline pragma, and indicate that it does not
4209 -- come from an aspect, as it applies to an internal entity.
4214 -- Fix up spec to be not imported any more
4221 -- Grab the subprogram declaration and specification
4225 -- Build parameter list that we need
4234 -- Build the call
4237 Stmt :=
4239 Expression =>
4244 else
4245 Stmt :=
4251 -- Now build the body
4253 Bod :=
4255 Specification =>
4259 Specification =>
4261 Iprag),
4262 Handled_Statement_Sequence =>
4267 -- Append the body to freeze result
4272 -- Case of imported subprogram that does not get wrapped
4274 else
4275 -- Set Is_Public. All imported entities need an external symbol
4276 -- created for them since they are always referenced from another
4277 -- object file. Note this used to be set when we set Is_Imported
4278 -- back in Sem_Prag, but now we delay it to this point, since we
4279 -- don't want to set this flag if we wrap an imported subprogram.
4285 -- Start of processing for Freeze_Entity
4287 begin
4288 -- The entity being frozen may be subject to pragma Ghost with policy
4289 -- Ignore. Set the mode now to ensure that any nodes generated during
4290 -- freezing are properly flagged as ignored Ghost.
4294 -- We are going to test for various reasons why this entity need not be
4295 -- frozen here, but in the case of an Itype that's defined within a
4296 -- record, that test actually applies to the record.
4302 then
4306 -- Do not freeze if already frozen since we only need one freeze node
4309 Restore_Globals;
4312 -- It is improper to freeze an external entity within a generic because
4313 -- its freeze node will appear in a non-valid context. The entity will
4314 -- be frozen in the proper scope after the current generic is analyzed.
4315 -- However, aspects must be analyzed because they may be queried later
4316 -- within the generic itself, and the corresponding pragma or attribute
4317 -- definition has not been analyzed yet.
4324 Restore_Globals;
4327 -- AI05-0213: A formal incomplete type does not freeze the actual. In
4328 -- the instance, the same applies to the subtype renaming the actual.
4334 then
4335 Restore_Globals;
4338 -- Formal subprograms are never frozen
4341 Restore_Globals;
4344 -- Generic types are never frozen as they lack delayed semantic checks
4347 Restore_Globals;
4350 -- Do not freeze a global entity within an inner scope created during
4351 -- expansion. A call to subprogram E within some internal procedure
4352 -- (a stream attribute for example) might require freezing E, but the
4353 -- freeze node must appear in the same declarative part as E itself.
4354 -- The two-pass elaboration mechanism in gigi guarantees that E will
4355 -- be frozen before the inner call is elaborated. We exclude constants
4356 -- from this test, because deferred constants may be frozen early, and
4357 -- must be diagnosed (e.g. in the case of a deferred constant being used
4358 -- in a default expression). If the enclosing subprogram comes from
4359 -- source, or is a generic instance, then the freeze point is the one
4360 -- mandated by the language, and we freeze the entity. A subprogram that
4361 -- is a child unit body that acts as a spec does not have a spec that
4362 -- comes from source, but can only come from source.
4367 then
4368 declare
4371 begin
4378 then
4380 else
4381 Restore_Globals;
4390 -- Similarly, an inlined instance body may make reference to global
4391 -- entities, but these references cannot be the proper freezing point
4392 -- for them, and in the absence of inlining freezing will take place in
4393 -- their own scope. Normally instance bodies are analyzed after the
4394 -- enclosing compilation, and everything has been frozen at the proper
4395 -- place, but with front-end inlining an instance body is compiled
4396 -- before the end of the enclosing scope, and as a result out-of-order
4397 -- freezing must be prevented.
4399 elsif Front_End_Inlining
4400 and then In_Instance_Body
4402 then
4403 declare
4406 begin
4411 else
4417 Restore_Globals;
4425 Restore_Globals;
4429 -- Add checks to detect proper initialization of scalars that may appear
4430 -- as subprogram parameters.
4436 -- Deal with delayed aspect specifications. The analysis of the aspect
4437 -- is required to be delayed to the freeze point, thus we analyze the
4438 -- pragma or attribute definition clause in the tree at this point. We
4439 -- also analyze the aspect specification node at the freeze point when
4440 -- the aspect doesn't correspond to pragma/attribute definition clause.
4446 -- Here to freeze the entity
4450 -- Case of entity being frozen is other than a type
4454 -- If entity is exported or imported and does not have an external
4455 -- name, now is the time to provide the appropriate default name.
4456 -- Skip this if the entity is stubbed, since we don't need a name
4457 -- for any stubbed routine. For the case on intrinsics, if no
4458 -- external name is specified, then calls will be handled in
4459 -- Exp_Intr.Expand_Intrinsic_Call, and no name is needed. If an
4460 -- external name is provided, then Expand_Intrinsic_Call leaves
4461 -- calls in place for expansion by GIGI.
4467 then
4468 Set_Encoded_Interface_Name
4471 -- If entity is an atomic object appearing in a declaration and
4472 -- the expression is an aggregate, assign it to a temporary to
4473 -- ensure that the actual assignment is done atomically rather
4474 -- than component-wise (the assignment to the temp may be done
4475 -- component-wise, but that is harmless).
4482 then
4486 -- Subprogram case
4490 -- Check for needing to wrap imported subprogram
4494 -- Freeze all parameter types and the return type (RM 13.14(14)).
4495 -- However skip this for internal subprograms. This is also where
4496 -- any extra formal parameters are created since we now know
4497 -- whether the subprogram will use a foreign convention.
4499 -- In Ada 2012, freezing a subprogram does not always freeze
4500 -- the corresponding profile (see AI05-019). An attribute
4501 -- reference is not a freezing point of the profile.
4502 -- Other constructs that should not freeze ???
4504 -- This processing doesn't apply to internal entities (see below)
4508 Restore_Globals;
4513 -- Must freeze its parent first if it is a derived subprogram
4519 -- We don't freeze internal subprograms, because we don't normally
4520 -- want addition of extra formals or mechanism setting to happen
4521 -- for those. However we do pass through predefined dispatching
4522 -- cases, since extra formals may be needed in some cases, such as
4523 -- for the stream 'Input function (build-in-place formals).
4527 then
4533 Restore_Globals;
4537 -- If warning on suspicious contracts then check for the case of
4538 -- a postcondition other than False for a No_Return subprogram.
4541 and then Warn_On_Suspicious_Contract
4543 then
4544 declare
4548 begin
4551 Name_Postcondition,
4552 Name_Refined_Post)
4553 then
4554 Exp :=
4555 Expression
4560 then
4561 Error_Msg_NE
4572 -- Here for other than a subprogram or type
4574 else
4575 -- If entity has a type, and it is not a generic unit, then
4576 -- freeze it first (RM 13.14(10)).
4580 then
4583 -- For an object of an anonymous array type, aspects on the
4584 -- object declaration apply to the type itself. This is the
4585 -- case for Atomic_Components, Volatile_Components, and
4586 -- Independent_Components. In these cases analysis of the
4587 -- generated pragma will mark the anonymous types accordingly,
4588 -- and the object itself does not require a freeze node.
4594 then
4601 -- Special processing for objects created by object declaration
4605 -- Abstract type allowed only for C++ imported variables or
4606 -- constants.
4608 -- Note: we inhibit this check for objects that do not come
4609 -- from source because there is at least one case (the
4610 -- expansion of x'Class'Input where x is abstract) where we
4611 -- legitimately generate an abstract object.
4617 then
4622 Error_Msg_NE
4627 Error_Msg_N -- CODEFIX
4633 -- For object created by object declaration, perform required
4634 -- categorization (preelaborate and pure) checks. Defer these
4635 -- checks to freeze time since pragma Import inhibits default
4636 -- initialization and thus pragma Import affects these checks.
4640 -- If there is an address clause, check that it is valid
4644 -- Reset Is_True_Constant for non-constant aliased object. We
4645 -- consider that the fact that a non-constant object is aliased
4646 -- may indicate that some funny business is going on, e.g. an
4647 -- aliased object is passed by reference to a procedure which
4648 -- captures the address of the object, which is later used to
4649 -- assign a new value, even though the compiler thinks that
4650 -- it is not modified. Such code is highly dubious, but we
4651 -- choose to make it "work" for non-constant aliased objects.
4652 -- Note that we used to do this for all aliased objects,
4653 -- whether or not constant, but this caused anomalies down
4654 -- the line because we ended up with static objects that
4655 -- were not Is_True_Constant. Not resetting Is_True_Constant
4656 -- for (aliased) constant objects ensures that this anomaly
4657 -- never occurs.
4659 -- However, we don't do that for internal entities. We figure
4660 -- that if we deliberately set Is_True_Constant for an internal
4661 -- entity, e.g. a dispatch table entry, then we mean it.
4666 then
4670 -- If the object needs any kind of default initialization, an
4671 -- error must be issued if No_Default_Initialization applies.
4672 -- The check doesn't apply to imported objects, which are not
4673 -- ever default initialized, and is why the check is deferred
4674 -- until freezing, at which point we know if Import applies.
4675 -- Deferred constants are also exempted from this test because
4676 -- their completion is explicit, or through an import pragma.
4680 then
4686 and then
4691 or else
4694 then
4696 Check_Restriction
4700 -- Check that a Thread_Local_Storage variable does not have
4701 -- default initialization, and any explicit initialization must
4702 -- either be the null constant or a static constant.
4705 declare
4707 begin
4708 if Has_Default_Initialization
4709 or else
4711 and then
4713 or else not
4715 or else
4717 then
4718 Error_Msg_NE
4721 Error_Msg_NE
4728 -- For imported objects, set Is_Public unless there is also an
4729 -- address clause, which means that there is no external symbol
4730 -- needed for the Import (Is_Public may still be set for other
4731 -- unrelated reasons). Note that we delayed this processing
4732 -- till freeze time so that we can be sure not to set the flag
4733 -- if there is an address clause. If there is such a clause,
4734 -- then the only purpose of the Import pragma is to suppress
4735 -- implicit initialization.
4741 -- For source objects that are not Imported and are library
4742 -- level, if no linker section pragma was given inherit the
4743 -- appropriate linker section from the corresponding type.
4749 then
4750 Set_Linker_Section_Pragma
4754 -- For convention C objects of an enumeration type, warn if
4755 -- the size is not integer size and no explicit size given.
4756 -- Skip warning for Boolean, and Character, assume programmer
4757 -- expects 8-bit sizes for these cases.
4760 or else
4767 then
4769 Error_Msg_N
4771 E);
4776 -- Check that a constant which has a pragma Volatile[_Components]
4777 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
4779 -- Note: Atomic[_Components] also sets Volatile[_Components]
4785 then
4786 -- Make sure we actually have a pragma, and have not merely
4787 -- inherited the indication from elsewhere (e.g. an address
4788 -- clause, which is not good enough in RM terms).
4791 or else
4793 then
4794 Error_Msg_N
4799 or else
4801 then
4802 Error_Msg_N
4808 -- Static objects require special handling
4812 then
4816 -- Remaining step is to layout objects
4820 then
4824 -- For an object that does not have delayed freezing, and whose
4825 -- initialization actions have been captured in a compound
4826 -- statement, move them back now directly within the enclosing
4827 -- statement sequence.
4831 then
4836 -- Case of a type or subtype being frozen
4838 else
4839 -- We used to check here that a full type must have preelaborable
4840 -- initialization if it completes a private type specified with
4841 -- pragma Preelaborable_Initialization, but that missed cases where
4842 -- the types occur within a generic package, since the freezing
4843 -- that occurs within a containing scope generally skips traversal
4844 -- of a generic unit's declarations (those will be frozen within
4845 -- instances). This check was moved to Analyze_Package_Specification.
4847 -- The type may be defined in a generic unit. This can occur when
4848 -- freezing a generic function that returns the type (which is
4849 -- defined in a parent unit). It is clearly meaningless to freeze
4850 -- this type. However, if it is a subtype, its size may be determi-
4851 -- nable and used in subsequent checks, so might as well try to
4852 -- compute it.
4854 -- In Ada 2012, Freeze_Entities is also used in the front end to
4855 -- trigger the analysis of aspect expressions, so in this case we
4856 -- want to continue the freezing process.
4860 and then
4863 then
4865 Restore_Globals;
4869 -- Check for error of Type_Invariant'Class applied to an untagged
4870 -- type (check delayed to freeze time when full type is available).
4872 declare
4874 begin
4878 then
4879 Error_Msg_NE
4882 Error_Msg_N
4887 -- A Ghost type cannot be effectively volatile (SPARK RM 6.9(8))
4891 then
4895 -- Deal with special cases of freezing for subtype
4899 -- Before we do anything else, a specialized test for the case of
4900 -- a size given for an array where the array needs to be packed,
4901 -- but was not so the size cannot be honored. This is the case
4902 -- where implicit packing may apply. The reason we do this so
4903 -- early is that if we have implicit packing, the layout of the
4904 -- base type is affected, so we must do this before we freeze
4905 -- the base type.
4907 -- We could do this processing only if implicit packing is enabled
4908 -- since in all other cases, the error would be caught by the back
4909 -- end. However, we choose to do the check even if we do not have
4910 -- implicit packing enabled, since this allows us to give a more
4911 -- useful error message (advising use of pragmas Implicit_Packing
4912 -- or Pack).
4915 declare
4926 -- Number of elements in array
4928 begin
4929 -- Check enabling conditions. These are straightforward
4930 -- except for the test for a limited composite type. This
4931 -- eliminates the rare case of a array of limited components
4932 -- where there are issues of whether or not we can go ahead
4933 -- and pack the array (since we can't freely pack and unpack
4934 -- arrays if they are limited).
4936 -- Note that we check the root type explicitly because the
4937 -- whole point is we are doing this test before we have had
4938 -- a chance to freeze the base type (and it is that freeze
4939 -- action that causes stuff to be inherited).
4952 then
4953 -- Compute number of elements in array
4961 and then
4963 then
4967 Num_Elmts :=
4968 Num_Elmts *
4974 -- What we are looking for here is the situation where
4975 -- the RM_Size given would be exactly right if there was
4976 -- a pragma Pack (resulting in the component size being
4977 -- the same as the RM_Size). Furthermore, the component
4978 -- type size must be an odd size (not a multiple of
4979 -- storage unit). If the component RM size is an exact
4980 -- number of storage units that is a power of two, the
4981 -- array is not packed and has a standard representation.
4985 then
4986 -- For implicit packing mode, just set the component
4987 -- size silently.
4995 -- Otherwise give an error message
4997 else
4998 Error_Msg_NE
5000 Error_Msg_N -- CODEFIX
5006 and then Implicit_Packing
5007 and then
5009 or else
5011 or else
5013 then
5014 -- Not a packed array, but indicate the desired
5015 -- component size, for the back-end.
5025 -- If ancestor subtype present, freeze that first. Note that this
5026 -- will also get the base type frozen. Need RM reference ???
5033 -- No ancestor subtype present
5035 else
5036 -- See if we have a nearest ancestor that has a predicate.
5037 -- That catches the case of derived type with a predicate.
5038 -- Need RM reference here ???
5046 -- Freeze base type before freezing the entity (RM 13.14(15))
5053 -- A subtype inherits all the type-related representation aspects
5054 -- from its parents (RM 13.1(8)).
5058 -- For a derived type, freeze its parent type first (RM 13.14(15))
5064 -- A derived type inherits each type-related representation aspect
5065 -- of its parent type that was directly specified before the
5066 -- declaration of the derived type (RM 13.1(15)).
5071 -- Check for incompatible size and alignment for record type
5073 if Warn_On_Size_Alignment
5077 -- If explicit Object_Size clause given assume that the programmer
5078 -- knows what he is doing, and expects the compiler behavior.
5082 -- Check for size not a multiple of alignment
5085 then
5086 declare
5092 begin
5095 -- Give a warning
5099 Error_Msg_NE
5105 else
5107 Error_Msg_NE
5120 -- Array type
5125 -- For a class-wide type, the corresponding specific type is
5126 -- frozen as well (RM 13.14(15))
5131 -- If the base type of the class-wide type is still incomplete,
5132 -- the class-wide remains unfrozen as well. This is legal when
5133 -- E is the formal of a primitive operation of some other type
5134 -- which is being frozen.
5138 Restore_Globals;
5142 -- The equivalent type associated with a class-wide subtype needs
5143 -- to be frozen to ensure that its layout is done.
5147 then
5151 -- Generate an itype reference for a library-level class-wide type
5152 -- at the freeze point. Otherwise the first explicit reference to
5153 -- the type may appear in an inner scope which will be rejected by
5154 -- the back-end.
5158 then
5159 declare
5162 begin
5165 -- From a gigi point of view, a class-wide subtype derives
5166 -- from its record equivalent type. As a result, the itype
5167 -- reference must appear after the freeze node of the
5168 -- equivalent type or gigi will reject the reference.
5172 then
5174 else
5180 -- For a record type or record subtype, freeze all component types
5181 -- (RM 13.14(15)). We test for E_Record_(sub)Type here, rather than
5182 -- using Is_Record_Type, because we don't want to attempt the freeze
5183 -- for the case of a private type with record extension (we will do
5184 -- that later when the full type is frozen).
5189 then
5192 -- For a concurrent type, freeze corresponding record type. This does
5193 -- not correspond to any specific rule in the RM, but the record type
5194 -- is essentially part of the concurrent type. Also freeze all local
5195 -- entities. This includes record types created for entry parameter
5196 -- blocks and whatever local entities may appear in the private part.
5210 -- The guard on the presence of the Etype seems to be needed
5211 -- for some CodePeer (-gnatcC) cases, but not clear why???
5216 then
5227 -- Private types are required to point to the same freeze node as
5228 -- their corresponding full views. The freeze node itself has to
5229 -- point to the partial view of the entity (because from the partial
5230 -- view, we can retrieve the full view, but not the reverse).
5231 -- However, in order to freeze correctly, we need to freeze the full
5232 -- view. If we are freezing at the end of a scope (or within the
5233 -- scope) of the private type, the partial and full views will have
5234 -- been swapped, the full view appears first in the entity chain and
5235 -- the swapping mechanism ensures that the pointers are properly set
5236 -- (on scope exit).
5238 -- If we encounter the partial view before the full view (e.g. when
5239 -- freezing from another scope), we freeze the full view, and then
5240 -- set the pointers appropriately since we cannot rely on swapping to
5241 -- fix things up (subtypes in an outer scope might not get swapped).
5243 -- If the full view is itself private, the above requirements apply
5244 -- to the underlying full view instead of the full view. But there is
5245 -- no swapping mechanism for the underlying full view so we need to
5246 -- set the pointers appropriately in both cases.
5250 then
5251 -- The construction of the dispatch table associated with library
5252 -- level tagged types forces freezing of all the primitives of the
5253 -- type, which may cause premature freezing of the partial view.
5254 -- For example:
5256 -- package Pkg is
5257 -- type T is tagged private;
5258 -- type DT is new T with private;
5259 -- procedure Prim (X : in out T; Y : in out DT'Class);
5260 -- private
5261 -- type T is tagged null record;
5262 -- Obj : T;
5263 -- type DT is new T with null record;
5264 -- end;
5266 -- In this case the type will be frozen later by the usual
5267 -- mechanism: an object declaration, an instantiation, or the
5268 -- end of a declarative part.
5272 then
5274 Restore_Globals;
5277 -- Case of full view present
5281 -- If full view has already been frozen, then no further
5282 -- processing is required
5288 -- Otherwise freeze full view and patch the pointers so that
5289 -- the freeze node will elaborate both views in the back end.
5290 -- However, if full view is itself private, freeze underlying
5291 -- full view instead and patch the pointers so that the freeze
5292 -- node will elaborate the three views in the back end.
5294 else
5295 declare
5298 begin
5301 then
5309 then
5316 else
5329 else
5330 -- {Incomplete,Private}_Subtypes with Full_Views
5331 -- constrained by discriminants.
5342 -- AI-117 requires that the convention of a partial view be the
5343 -- same as the convention of the full view. Note that this is a
5344 -- recognized breach of privacy, but it's essential for logical
5345 -- consistency of representation, and the lack of a rule in
5346 -- RM95 was an oversight.
5353 -- Size information is copied from the full view to the
5354 -- incomplete or private view for consistency.
5356 -- We skip this is the full view is not a type. This is very
5357 -- strange of course, and can only happen as a result of
5358 -- certain illegalities, such as a premature attempt to derive
5359 -- from an incomplete type.
5366 Restore_Globals;
5369 -- Case of underlying full view present
5373 then
5378 -- Patch the pointers so that the freeze node will elaborate
5379 -- both views in the back end.
5388 else
5396 Restore_Globals;
5399 -- Case of no full view present. If entity is derived or subtype,
5400 -- it is safe to freeze, correctness depends on the frozen status
5401 -- of parent. Otherwise it is either premature usage, or a Taft
5402 -- amendment type, so diagnosis is at the point of use and the
5403 -- type might be frozen later.
5408 else
5410 Restore_Globals;
5414 -- For access subprogram, freeze types of all formals, the return
5415 -- type was already frozen, since it is the Etype of the function.
5416 -- Formal types can be tagged Taft amendment types, but otherwise
5417 -- they cannot be incomplete.
5425 then
5429 -- AI05-151: Incomplete types are allowed in access to
5430 -- subprogram specifications.
5433 Error_Msg_NE
5444 -- For access to a protected subprogram, freeze the equivalent type
5445 -- (however this is not set if we are not generating code or if this
5446 -- is an anonymous type used just for resolution).
5454 -- Generic types are never seen by the back-end, and are also not
5455 -- processed by the expander (since the expander is turned off for
5456 -- generic processing), so we never need freeze nodes for them.
5459 Restore_Globals;
5463 -- Some special processing for non-generic types to complete
5464 -- representation details not known till the freeze point.
5469 -- Some error checks required for ordinary fixed-point type. Defer
5470 -- these till the freeze-point since we need the small and range
5471 -- values. We only do these checks for base types
5476 Error_Msg_N
5481 Error_Msg_N
5487 Error_Msg_N
5493 Error_Msg_N
5505 and then Warn_On_Suspicious_Modulus_Value
5506 then
5510 -- The pool applies to named and anonymous access types, but not
5511 -- to subprogram and to internal types generated for 'Access
5512 -- references.
5517 then
5518 -- If a pragma Default_Storage_Pool applies, and this type has no
5519 -- Storage_Pool or Storage_Size clause (which must have occurred
5520 -- before the freezing point), then use the default. This applies
5521 -- only to base types.
5523 -- None of this applies to access to subprograms, for which there
5524 -- are clearly no pools.
5530 then
5531 -- Case of pragma Default_Storage_Pool (null)
5536 -- Case of pragma Default_Storage_Pool (storage_pool_NAME)
5538 else
5543 -- Check restriction for standard storage pool
5549 -- Deal with error message for pure access type. This is not an
5550 -- error in Ada 2005 if there is no pool (see AI-366).
5556 then
5560 Error_Msg_N
5564 Error_Msg_N
5567 else
5568 Error_Msg_N
5575 -- Case of composite types
5579 -- AI-117 requires that all new primitives of a tagged type must
5580 -- inherit the convention of the full view of the type. Inherited
5581 -- and overriding operations are defined to inherit the convention
5582 -- of their parent or overridden subprogram (also specified in
5583 -- AI-117), which will have occurred earlier (in Derive_Subprogram
5584 -- and New_Overloaded_Entity). Here we set the convention of
5585 -- primitives that are still convention Ada, which will ensure
5586 -- that any new primitives inherit the type's convention. Class-
5587 -- wide types can have a foreign convention inherited from their
5588 -- specific type, but are excluded from this since they don't have
5589 -- any associated primitives.
5594 then
5595 declare
5599 begin
5611 -- If the type is a simple storage pool type, then this is where
5612 -- we attempt to locate and validate its Allocate, Deallocate, and
5613 -- Storage_Size operations (the first is required, and the latter
5614 -- two are optional). We also verify that the full type for a
5615 -- private type is allowed to be a simple storage pool type.
5619 then
5620 -- If the type is marked Has_Private_Declaration, then this is
5621 -- a full type for a private type that was specified with the
5622 -- pragma Simple_Storage_Pool_Type, and here we ensure that the
5623 -- pragma is allowed for the full type (for example, it can't
5624 -- be an array type, or a nonlimited record type).
5629 then
5631 Error_Msg_N
5642 procedure Validate_Simple_Pool_Op_Formal
5649 -- Validate one formal Pool_Op_Formal of the candidate pool
5650 -- operation Pool_Op. The formal must be of Expected_Type
5651 -- and have mode Expected_Mode. OK_Formal will be set to
5652 -- False if the formal doesn't match. If OK_Formal is False
5653 -- on entry, then the formal will effectively be ignored
5654 -- (because validation of the pool op has already failed).
5655 -- Upon return, Pool_Op_Formal will be updated to the next
5656 -- formal, if any.
5658 procedure Validate_Simple_Pool_Operation
5660 -- Search for and validate a simple pool operation with the
5661 -- name Op_Name. If the name is Allocate, then there must be
5662 -- exactly one such primitive operation for the simple pool
5663 -- type. If the name is Deallocate or Storage_Size, then
5664 -- there can be at most one such primitive operation. The
5665 -- profile of the located primitive must conform to what
5666 -- is expected for each operation.
5668 ------------------------------------
5669 -- Validate_Simple_Pool_Op_Formal --
5670 ------------------------------------
5672 procedure Validate_Simple_Pool_Op_Formal
5679 is
5680 begin
5681 -- If OK_Formal is False on entry, then simply ignore
5682 -- the formal, because an earlier formal has already
5683 -- been flagged.
5688 -- If no formal is passed in, then issue an error for a
5689 -- missing formal.
5692 Error_Msg_NE
5702 -- If the pool type was expected for this formal, then
5703 -- this will not be considered a candidate operation
5704 -- for the simple pool, so we unset OK_Formal so that
5705 -- the op and any later formals will be ignored.
5712 else
5713 Error_Msg_NE
5720 -- Issue error if formal's mode is not the expected one
5723 Error_Msg_N
5725 Pool_Op_Formal);
5728 -- Advance to the next formal
5733 ------------------------------------
5734 -- Validate_Simple_Pool_Operation --
5735 ------------------------------------
5737 procedure Validate_Simple_Pool_Operation
5739 is
5745 begin
5746 pragma Assert
5748 Name_Deallocate,
5749 Name_Storage_Size));
5753 -- For each homonym declared immediately in the scope
5754 -- of the simple storage pool type, determine whether
5755 -- the homonym is an operation of the pool type, and,
5756 -- if so, check that its profile is as expected for
5757 -- a simple pool operation of that name.
5763 then
5768 -- The first parameter must be of the pool type
5769 -- in order for the operation to qualify.
5772 Validate_Simple_Pool_Op_Formal
5775 else
5776 Validate_Simple_Pool_Op_Formal
5781 -- If another operation with this name has already
5782 -- been located for the type, then flag an error,
5783 -- since we only allow the type to have a single
5784 -- such primitive.
5787 Error_Msg_NE
5792 -- In the case of Allocate and Deallocate, a formal
5793 -- of type System.Address is required.
5796 Validate_Simple_Pool_Op_Formal
5801 Validate_Simple_Pool_Op_Formal
5806 -- In the case of Allocate and Deallocate, formals
5807 -- of type Storage_Count are required as the third
5808 -- and fourth parameters.
5811 Validate_Simple_Pool_Op_Formal
5814 Validate_Simple_Pool_Op_Formal
5819 -- If no mismatched formals have been found (Is_OK)
5820 -- and no excess formals are present, then this
5821 -- operation has been validated, so record it.
5831 -- There must be a valid Allocate operation for the type,
5832 -- so issue an error if none was found.
5836 then
5842 -- Simple pool operations can't be abstract
5845 Error_Msg_N
5850 -- The Storage_Size operation must be a function with
5851 -- Storage_Count as its result type.
5855 Error_Msg_N
5859 Error_Msg_NE
5864 -- Allocate and Deallocate must be procedures
5867 Error_Msg_N
5873 -- Start of processing for Validate_Simple_Pool_Ops
5875 begin
5883 -- Now that all types from which E may depend are frozen, see if the
5884 -- size is known at compile time, if it must be unsigned, or if
5885 -- strict alignment is required
5894 -- Do not allow a size clause for a type which does not have a size
5895 -- that is known at compile time
5899 then
5900 -- Suppress this message if errors posted on E, even if we are
5901 -- in all errors mode, since this is often a junk message
5904 Error_Msg_N
5910 -- Now we set/verify the representation information, in particular
5911 -- the size and alignment values. This processing is not required for
5912 -- generic types, since generic types do not play any part in code
5913 -- generation, and so the size and alignment values for such types
5914 -- are irrelevant. Ditto for types declared within a generic unit,
5915 -- which may have components that depend on generic parameters, and
5916 -- that will be recreated in an instance.
5921 -- Otherwise we call the layout procedure
5923 else
5927 -- If this is an access to subprogram whose designated type is itself
5928 -- a subprogram type, the return type of this anonymous subprogram
5929 -- type must be decorated as well.
5933 then
5937 -- If the type has a Defaut_Value/Default_Component_Value aspect,
5938 -- this is where we analye the expression (after the type is frozen,
5939 -- since in the case of Default_Value, we are analyzing with the
5940 -- type itself, and we treat Default_Component_Value similarly for
5941 -- the sake of uniformity).
5944 declare
5949 begin
5954 else
5965 Flag_Non_Static_Expr
5972 -- End of freeze processing for type entities
5975 -- Here is where we logically freeze the current entity. If it has a
5976 -- freeze node, then this is the point at which the freeze node is
5977 -- linked into the result list.
5981 -- If a freeze node is already allocated, use it, otherwise allocate
5982 -- a new one. The preallocation happens in the case of anonymous base
5983 -- types, where we preallocate so that we can set First_Subtype_Link.
5984 -- Note that we reset the Sloc to the current freeze location.
5990 else
6001 -- A final pass over record types with discriminants. If the type
6002 -- has an incomplete declaration, there may be constrained access
6003 -- subtypes declared elsewhere, which do not depend on the discrimi-
6004 -- nants of the type, and which are used as component types (i.e.
6005 -- the full view is a recursive type). The designated types of these
6006 -- subtypes can only be elaborated after the type itself, and they
6007 -- need an itype reference.
6011 then
6012 declare
6017 begin
6027 then
6039 -- When a type is frozen, the first subtype of the type is frozen as
6040 -- well (RM 13.14(15)). This has to be done after freezing the type,
6041 -- since obviously the first subtype depends on its own base type.
6046 -- If we just froze a tagged non-class wide record, then freeze the
6047 -- corresponding class-wide type. This must be done after the tagged
6048 -- type itself is frozen, because the class-wide type refers to the
6049 -- tagged type which generates the class.
6054 then
6061 -- Special handling for subprograms
6065 -- If subprogram has address clause then reset Is_Public flag, since
6066 -- we do not want the backend to generate external references.
6070 then
6075 Restore_Globals;
6079 -----------------------------
6080 -- Freeze_Enumeration_Type --
6081 -----------------------------
6084 begin
6085 -- By default, if no size clause is present, an enumeration type with
6086 -- Convention C is assumed to interface to a C enum, and has integer
6087 -- size. This applies to types. For subtypes, verify that its base
6088 -- type has no size clause either. Treat other foreign conventions
6089 -- in the same way, and also make sure alignment is set right.
6096 -- Don't do this if Short_Enums on target
6098 and then not Target_Short_Enums
6099 then
6103 -- Normal Ada case or size clause present or not Long_C_Enums on target
6105 else
6106 -- If the enumeration type interfaces to C, and it has a size clause
6107 -- that specifies less than int size, it warrants a warning. The
6108 -- user may intend the C type to be an enum or a char, so this is
6109 -- not by itself an error that the Ada compiler can detect, but it
6110 -- it is a worth a heads-up. For Boolean and Character types we
6111 -- assume that the programmer has the proper C type in mind.
6119 -- Don't do this if Short_Enums on target
6121 and then not Target_Short_Enums
6122 then
6123 Error_Msg_N
6131 -----------------------
6132 -- Freeze_Expression --
6133 -----------------------
6144 -- This flag is set true if the entity must be frozen outside the
6145 -- current subprogram. This happens in the case of expander generated
6146 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
6147 -- not freeze all entities like other bodies, but which nevertheless
6148 -- may reference entities that have to be frozen before the body and
6149 -- obviously cannot be frozen inside the body.
6152 -- If the expression is an array aggregate, the type of the component
6153 -- expressions is also frozen. If the component type is an access type
6154 -- and the expressions include allocators, the designed type is frozen
6155 -- as well.
6158 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
6159 -- it is the handled statement sequence of an expander-generated
6160 -- subprogram (init proc, stream subprogram, or renaming as body).
6161 -- If so, this is not a freezing context.
6163 -----------------------------------------
6164 -- Find_Aggregate_Component_Desig_Type --
6165 -----------------------------------------
6171 begin
6197 ----------------------
6198 -- In_Expanded_Body --
6199 ----------------------
6205 begin
6208 else
6215 else
6218 -- The following are expander-created bodies, or bodies that
6219 -- are not freeze points.
6228 N_Subprogram_Renaming_Declaration,
6229 N_Expression_Function))
6230 then
6232 else
6238 -- Start of processing for Freeze_Expression
6240 begin
6241 -- Immediate return if freezing is inhibited. This flag is set by the
6242 -- analyzer to stop freezing on generated expressions that would cause
6243 -- freezing if they were in the source program, but which are not
6244 -- supposed to freeze, since they are created.
6250 -- If expression is non-static, then it does not freeze in a default
6251 -- expression, see section "Handling of Default Expressions" in the
6252 -- spec of package Sem for further details. Note that we have to make
6253 -- sure that we actually have a real expression (if we have a subtype
6254 -- indication, we can't test Is_OK_Static_Expression). However, we
6255 -- exclude the case of the prefix of an attribute of a static scalar
6256 -- subtype from this early return, because static subtype attributes
6257 -- should always cause freezing, even in default expressions, but
6258 -- the attribute may not have been marked as static yet (because in
6259 -- Resolve_Attribute, the call to Eval_Attribute follows the call of
6260 -- Freeze_Expression on the prefix).
6262 if In_Spec_Exp
6269 then
6273 -- Freeze type of expression if not frozen already
6281 -- Base type may be an derived numeric type that is frozen at
6282 -- the point of declaration, but first_subtype is still unfrozen.
6289 -- For entity name, freeze entity if not frozen already. A special
6290 -- exception occurs for an identifier that did not come from source.
6291 -- We don't let such identifiers freeze a non-internal entity, i.e.
6292 -- an entity that did come from source, since such an identifier was
6293 -- generated by the expander, and cannot have any semantic effect on
6294 -- the freezing semantics. For example, this stops the parameter of
6295 -- an initialization procedure from freezing the variable.
6302 then
6309 else
6313 -- For an allocator freeze designated type if not frozen already
6315 -- For an aggregate whose component type is an access type, freeze the
6316 -- designated type now, so that its freeze does not appear within the
6317 -- loop that might be created in the expansion of the aggregate. If the
6318 -- designated type is a private type without full view, the expression
6319 -- cannot contain an allocator, so the type is not frozen.
6321 -- For a function, we freeze the entity when the subprogram declaration
6322 -- is frozen, but a function call may appear in an initialization proc.
6323 -- before the declaration is frozen. We need to generate the extra
6324 -- formals, if any, to ensure that the expansion of the call includes
6325 -- the proper actuals. This only applies to Ada subprograms, not to
6326 -- imported ones.
6337 then
6339 -- Check whether aggregate includes allocators.
6344 when N_Selected_Component |
6345 N_Indexed_Component |
6346 N_Slice =>
6357 then
6368 then
6372 -- All done if nothing needs freezing
6377 then
6381 -- Examine the enclosing context by climbing the parent chain. The
6382 -- traversal serves two purposes - to detect scenarios where freezeing
6383 -- is not needed and to find the proper insertion point for the freeze
6384 -- nodes. Although somewhat similar to Insert_Actions, this traversal
6385 -- is freezing semantics-sensitive. Inserting freeze nodes blindly in
6386 -- the tree may result in types being frozen too early.
6389 loop
6392 -- If we don't have a parent, then we are not in a well-formed tree.
6393 -- This is an unusual case, but there are some legitimate situations
6394 -- in which this occurs, notably when the expressions in the range of
6395 -- a type declaration are resolved. We simply ignore the freeze
6396 -- request in this case. Is this right ???
6402 -- See if we have got to an appropriate point in the tree
6406 -- A special test for the exception of (RM 13.14(8)) for the case
6407 -- of per-object expressions (RM 3.8(18)) occurring in component
6408 -- definition or a discrete subtype definition. Note that we test
6409 -- for a component declaration which includes both cases we are
6410 -- interested in, and furthermore the tree does not have explicit
6411 -- nodes for either of these two constructs.
6415 -- The case we want to test for here is an identifier that is
6416 -- a per-object expression, this is either a discriminant that
6417 -- appears in a context other than the component declaration
6418 -- or it is a reference to the type of the enclosing construct.
6420 -- For either of these cases, we skip the freezing
6422 if not In_Spec_Expression
6425 then
6426 -- We recognize the discriminant case by just looking for
6427 -- a reference to a discriminant. It can only be one for
6428 -- the enclosing construct. Skip freezing in this case.
6433 -- For the case of a reference to the enclosing record,
6434 -- (or task or protected type), we look for a type that
6435 -- matches the current scope.
6442 -- If we have an enumeration literal that appears as the choice in
6443 -- the aggregate of an enumeration representation clause, then
6444 -- freezing does not occur (RM 13.14(10)).
6448 -- The case we are looking for is an enumeration literal
6452 then
6453 -- If enumeration literal appears directly as the choice,
6454 -- do not freeze (this is the normal non-overloaded case)
6458 then
6461 -- If enumeration literal appears as the name of function
6462 -- which is the choice, then also do not freeze. This
6463 -- happens in the overloaded literal case, where the
6464 -- enumeration literal is temporarily changed to a function
6465 -- call for overloading analysis purposes.
6468 and then
6470 and then
6472 then
6477 -- Normally if the parent is a handled sequence of statements,
6478 -- then the current node must be a statement, and that is an
6479 -- appropriate place to insert a freeze node.
6483 -- An exception occurs when the sequence of statements is for
6484 -- an expander generated body that did not do the usual freeze
6485 -- all operation. In this case we usually want to freeze
6486 -- outside this body, not inside it, and we skip past the
6487 -- subprogram body that we are inside.
6490 declare
6494 begin
6495 -- Freeze the entity only when it is declared inside the
6496 -- body of the expander generated procedure. This case
6497 -- is recognized by the scope of the entity or its type,
6498 -- which is either the spec for some enclosing body, or
6499 -- (in the case of init_procs, for which there are no
6500 -- separate specs) the current scope.
6506 or else
6508 then
6514 then
6519 -- An expression function may act as a completion of
6520 -- a function declaration. As such, it can reference
6521 -- entities declared between the two views:
6523 -- Hidden []; -- 1
6524 -- function F return ...;
6525 -- private
6526 -- function Hidden return ...;
6527 -- function F return ... is (Hidden); -- 2
6529 -- Refering to the example above, freezing the expression
6530 -- of F (2) would place Hidden's freeze node (1) in the
6531 -- wrong place. Avoid explicit freezing and let the usual
6532 -- scenarios do the job - for example, reaching the end
6533 -- of the private declarations, or a call to F.
6536 N_Expression_Function
6537 then
6540 -- Freeze outside the body
6542 else
6548 -- Here if normal case where we are in handled statement
6549 -- sequence and want to do the insertion right there.
6551 else
6555 -- If parent is a body or a spec or a block, then the current node
6556 -- is a statement or declaration and we can insert the freeze node
6557 -- before it.
6559 when N_Block_Statement |
6560 N_Entry_Body |
6561 N_Package_Body |
6562 N_Package_Specification |
6563 N_Protected_Body |
6564 N_Subprogram_Body |
6567 -- The expander is allowed to define types in any statements list,
6568 -- so any of the following parent nodes also mark a freezing point
6569 -- if the actual node is in a list of statements or declarations.
6571 when N_Abortable_Part |
6572 N_Accept_Alternative |
6573 N_And_Then |
6574 N_Case_Statement_Alternative |
6575 N_Compilation_Unit_Aux |
6576 N_Conditional_Entry_Call |
6577 N_Delay_Alternative |
6578 N_Elsif_Part |
6579 N_Entry_Call_Alternative |
6580 N_Exception_Handler |
6581 N_Extended_Return_Statement |
6582 N_Freeze_Entity |
6583 N_If_Statement |
6584 N_Or_Else |
6585 N_Selective_Accept |
6586 N_Triggering_Alternative =>
6590 -- Freeze nodes produced by an expression coming from the Actions
6591 -- list of a N_Expression_With_Actions node must remain within the
6592 -- Actions list. Inserting the freeze nodes further up the tree
6593 -- may lead to use before declaration issues in the case of array
6594 -- types.
6599 then
6603 -- Note: N_Loop_Statement is a special case. A type that appears
6604 -- in the source can never be frozen in a loop (this occurs only
6605 -- because of a loop expanded by the expander), so we keep on
6606 -- going. Otherwise we terminate the search. Same is true of any
6607 -- entity which comes from source. (if they have predefined type,
6608 -- that type does not appear to come from source, but the entity
6609 -- should not be frozen here).
6615 -- For all other cases, keep looking at parents
6621 -- We fall through the case if we did not yet find the proper
6622 -- place in the free for inserting the freeze node, so climb.
6627 -- If the expression appears in a record or an initialization procedure,
6628 -- the freeze nodes are collected and attached to the current scope, to
6629 -- be inserted and analyzed on exit from the scope, to insure that
6630 -- generated entities appear in the correct scope. If the expression is
6631 -- a default for a discriminant specification, the scope is still void.
6632 -- The expression can also appear in the discriminant part of a private
6633 -- or concurrent type.
6635 -- If the expression appears in a constrained subcomponent of an
6636 -- enclosing record declaration, the freeze nodes must be attached to
6637 -- the outer record type so they can eventually be placed in the
6638 -- enclosing declaration list.
6640 -- The other case requiring this special handling is if we are in a
6641 -- default expression, since in that case we are about to freeze a
6642 -- static type, and the freeze scope needs to be the outer scope, not
6643 -- the scope of the subprogram with the default parameter.
6645 -- For default expressions and other spec expressions in generic units,
6646 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
6647 -- placing them at the proper place, after the generic unit.
6650 or else Freeze_Outside
6655 then
6656 declare
6661 begin
6674 -- The current scope may be that of a constrained component of
6675 -- an enclosing record declaration, or of a loop of an enclosing
6676 -- quantified expression, which is above the current scope in the
6677 -- scope stack. Indeed in the context of a quantified expression,
6678 -- a scope is created and pushed above the current scope in order
6679 -- to emulate the loop-like behavior of the quantified expression.
6680 -- If the expression is within a top-level pragma, as for a pre-
6681 -- condition on a library-level subprogram, nothing to do.
6686 N_Quantified_Expression)
6687 then
6694 Freeze_Nodes;
6695 else
6705 -- Now we have the right place to do the freezing. First, a special
6706 -- adjustment, if we are in spec-expression analysis mode, these freeze
6707 -- actions must not be thrown away (normally all inserted actions are
6708 -- thrown away in this mode. However, the freeze actions are from static
6709 -- expressions and one of the important reasons we are doing this
6710 -- special analysis is to get these freeze actions. Therefore we turn
6711 -- off the In_Spec_Expression mode to propagate these freeze actions.
6712 -- This also means they get properly analyzed and expanded.
6716 -- Freeze the designated type of an allocator (RM 13.14(13))
6722 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
6723 -- the enumeration representation clause exception in the loop above.
6729 -- Freeze name if one is present (RM 13.14(11))
6735 -- Restore In_Spec_Expression flag
6740 -----------------------------
6741 -- Freeze_Fixed_Point_Type --
6742 -----------------------------
6744 -- Certain fixed-point types and subtypes, including implicit base types
6745 -- and declared first subtypes, have not yet set up a range. This is
6746 -- because the range cannot be set until the Small and Size values are
6747 -- known, and these are not known till the type is frozen.
6749 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
6750 -- whose bounds are unanalyzed real literals. This routine will recognize
6751 -- this case, and transform this range node into a properly typed range
6752 -- with properly analyzed and resolved values.
6769 -- Save original bounds (for shaving tests)
6772 -- Actual size chosen
6775 -- Returns size of type with given bounds. Also leaves these
6776 -- bounds set as the current bounds of the Typ.
6778 -----------
6779 -- Fsize --
6780 -----------
6783 begin
6789 -- Start of processing for Freeze_Fixed_Point_Type
6791 begin
6792 -- If Esize of a subtype has not previously been set, set it now
6799 else
6804 -- Immediate return if the range is already analyzed. This means that
6805 -- the range is already set, and does not need to be computed by this
6806 -- routine.
6812 -- Immediate return if either of the bounds raises Constraint_Error
6816 then
6826 -- Ordinary fixed-point case
6830 -- For the ordinary fixed-point case, we are allowed to fudge the
6831 -- end-points up or down by small. Generally we prefer to fudge up,
6832 -- i.e. widen the bounds for non-model numbers so that the end points
6833 -- are included. However there are cases in which this cannot be
6834 -- done, and indeed cases in which we may need to narrow the bounds.
6835 -- The following circuit makes the decision.
6837 -- Note: our terminology here is that Incl_EP means that the bounds
6838 -- are widened by Small if necessary to include the end points, and
6839 -- Excl_EP means that the bounds are narrowed by Small to exclude the
6840 -- end-points if this reduces the size.
6842 -- Note that in the Incl case, all we care about is including the
6843 -- end-points. In the Excl case, we want to narrow the bounds as
6844 -- much as permitted by the RM, to give the smallest possible size.
6861 begin
6862 -- First step. Base types are required to be symmetrical. Right
6863 -- now, the base type range is a copy of the first subtype range.
6864 -- This will be corrected before we are done, but right away we
6865 -- need to deal with the case where both bounds are non-negative.
6866 -- In this case, we set the low bound to the negative of the high
6867 -- bound, to make sure that the size is computed to include the
6868 -- required sign. Note that we do not need to worry about the
6869 -- case of both bounds negative, because the sign will be dealt
6870 -- with anyway. Furthermore we can't just go making such a bound
6871 -- symmetrical, since in a twos-complement system, there is an
6872 -- extra negative value which could not be accommodated on the
6873 -- positive side.
6878 then
6883 -- Compute the fudged bounds. If the number is a model number,
6884 -- then we do nothing to include it, but we are allowed to backoff
6885 -- to the next adjacent model number when we exclude it. If it is
6886 -- not a model number then we straddle the two values with the
6887 -- model numbers on either side.
6893 else
6897 -- The low value excluding the end point is Small greater, but
6898 -- we do not do this exclusion if the low value is positive,
6899 -- since it can't help the size and could actually hurt by
6900 -- crossing the high bound.
6905 -- If the value went from negative to zero, then we have the
6906 -- case where Loval_Incl_EP is the model number just below
6907 -- zero, so we want to stick to the negative value for the
6908 -- base type to maintain the condition that the size will
6909 -- include signed values.
6913 then
6917 else
6921 -- Similar processing for upper bound and high value
6927 else
6933 else
6937 -- One further adjustment is needed. In the case of subtypes, we
6938 -- cannot go outside the range of the base type, or we get
6939 -- peculiarities, and the base type range is already set. This
6940 -- only applies to the Incl values, since clearly the Excl values
6941 -- are already as restricted as they are allowed to be.
6948 -- Get size including and excluding end points
6953 -- No need to exclude end-points if it does not reduce size
6963 -- Now we set the actual size to be used. We want to use the
6964 -- bounds fudged up to include the end-points but only if this
6965 -- can be done without violating a specifically given size
6966 -- size clause or causing an unacceptable increase in size.
6968 -- Case of size clause given
6972 -- Use the inclusive size only if it is consistent with
6973 -- the explicitly specified size.
6980 -- If the inclusive size is too large, we try excluding
6981 -- the end-points (will be caught later if does not work).
6983 else
6989 -- Case of size clause not given
6991 else
6992 -- If we have a base type whose corresponding first subtype
6993 -- has an explicit size that is large enough to include our
6994 -- end-points, then do so. There is no point in working hard
6995 -- to get a base type whose size is smaller than the specified
6996 -- size of the first subtype.
7002 then
7007 -- If excluding the end-points makes the size smaller and
7008 -- results in a size of 8,16,32,64, then we take the smaller
7009 -- size. For the 64 case, this is compulsory. For the other
7010 -- cases, it seems reasonable. We like to include end points
7011 -- if we can, but not at the expense of moving to the next
7012 -- natural boundary of size.
7016 then
7021 -- Otherwise we can definitely include the end points
7023 else
7029 -- One pathological case: normally we never fudge a low bound
7030 -- down, since it would seem to increase the size (if it has
7031 -- any effect), but for ranges containing single value, or no
7032 -- values, the high bound can be small too large. Consider:
7034 -- type t is delta 2.0**(-14)
7035 -- range 131072.0 .. 0;
7037 -- That lower bound is *just* outside the range of 32 bits, and
7038 -- does need fudging down in this case. Note that the bounds
7039 -- will always have crossed here, since the high bound will be
7040 -- fudged down if necessary, as in the case of:
7042 -- type t is delta 2.0**(-14)
7043 -- range 131072.0 .. 131072.0;
7045 -- So we detect the situation by looking for crossed bounds,
7046 -- and if the bounds are crossed, and the low bound is greater
7047 -- than zero, we will always back it off by small, since this
7048 -- is completely harmless.
7055 -- And of course, we need to do exactly the same parallel
7056 -- fudge for flat ranges in the negative region.
7069 -- For the decimal case, none of this fudging is required, since there
7070 -- are no end-point problems in the decimal case (the end-points are
7071 -- always included).
7073 else
7077 -- At this stage, the actual size has been calculated and the proper
7078 -- required bounds are stored in the low and high bounds.
7082 Error_Msg_N
7084 Typ);
7088 -- Check size against explicit given size
7094 Error_Msg_NE
7098 else
7102 -- Increase size to next natural boundary if no size clause given
7104 else
7111 else
7119 -- If we have a base type, then expand the bounds so that they extend to
7120 -- the full width of the allocated size in bits, to avoid junk range
7121 -- checks on intermediate computations.
7128 -- Final step is to reanalyze the bounds using the proper type
7129 -- and set the Corresponding_Integer_Value fields of the literals.
7135 -- Resolve with universal fixed if the base type, and the base type if
7136 -- it is a subtype. Note we can't resolve the base type with itself,
7137 -- that would be a reference before definition.
7141 else
7145 -- Set corresponding integer value for bound
7147 Set_Corresponding_Integer_Value
7150 -- Similar processing for high bound
7158 else
7162 Set_Corresponding_Integer_Value
7165 -- Set type of range to correspond to bounds
7169 -- Set Esize to calculated size if not set already
7175 -- Set RM_Size if not already set. If already set, check value
7177 declare
7180 begin
7185 Error_Msg_NE
7190 else
7195 -- Check for shaving
7199 Error_Msg_N
7201 Error_Msg_N
7206 Error_Msg_N
7208 Error_Msg_N
7214 ------------------
7215 -- Freeze_Itype --
7216 ------------------
7221 begin
7230 --------------------------
7231 -- Freeze_Static_Object --
7232 --------------------------
7237 -- Exception raised if the type of a static object cannot be made
7238 -- static. This happens if the type depends on non-global objects.
7241 -- Called to ensure that an expression used as part of a type definition
7242 -- is statically allocatable, which means that the expression type is
7243 -- statically allocatable, and the expression is either static, or a
7244 -- reference to a library level constant.
7247 -- Called to mark a type as static, checking that it is possible
7248 -- to set the type as static. If it is not possible, then the
7249 -- exception Cannot_Be_Static is raised.
7251 -----------------------------
7252 -- Ensure_Expression_Is_SA --
7253 -----------------------------
7258 begin
7270 then
7278 -----------------------
7279 -- Ensure_Type_Is_SA --
7280 -----------------------
7286 begin
7287 -- If type is library level, we are all set
7293 -- We are also OK if the type already marked as statically allocated,
7294 -- which means we processed it before.
7300 -- Mark type as statically allocated
7304 -- Check that it is safe to statically allocate this type
7322 declare
7326 begin
7338 else
7347 then
7366 else
7371 -- Start of processing for Freeze_Static_Object
7373 begin
7376 exception
7379 -- If the object that cannot be static is imported or exported, then
7380 -- issue an error message saying that this object cannot be imported
7381 -- or exported. If it has an address clause it is an overlay in the
7382 -- current partition and the static requirement is not relevant.
7383 -- Do not issue any error message when ignoring rep clauses.
7390 Error_Msg_N
7394 -- Otherwise must be exported, something is wrong if compiler
7395 -- is marking something as statically allocated which cannot be).
7398 Error_Msg_N
7403 -----------------------
7404 -- Freeze_Subprogram --
7405 -----------------------
7411 begin
7412 -- Subprogram may not have an address clause unless it is imported
7416 Error_Msg_N
7423 -- Reset the Pure indication on an imported subprogram unless an
7424 -- explicit Pure_Function pragma was present or the subprogram is an
7425 -- intrinsic. We do this because otherwise it is an insidious error
7426 -- to call a non-pure function from pure unit and have calls
7427 -- mysteriously optimized away. What happens here is that the Import
7428 -- can bypass the normal check to ensure that pure units call only pure
7429 -- subprograms.
7431 -- The reason for the intrinsic exception is that in general, intrinsic
7432 -- functions (such as shifts) are pure anyway. The only exceptions are
7433 -- the intrinsics in GNAT.Source_Info, and that unit is not marked Pure
7434 -- in any case, so no problem arises.
7440 then
7444 -- For non-foreign convention subprograms, this is where we create
7445 -- the extra formals (for accessibility level and constrained bit
7446 -- information). We delay this till the freeze point precisely so
7447 -- that we know the convention.
7453 -- If this is convention Ada and a Valued_Procedure, that's odd
7458 and then Warn_On_Export_Import
7459 then
7460 Error_Msg_N
7465 -- Case of foreign convention
7467 else
7470 -- For foreign conventions, warn about return of unconstrained array
7475 -- If no return type, probably some other error, e.g. a
7476 -- missing full declaration, so ignore.
7481 -- If the return type is generic, we have emitted a warning
7482 -- earlier on, and there is nothing else to check here. Specific
7483 -- instantiations may lead to erroneous behavior.
7488 -- Display warning if returning unconstrained array
7493 -- Check appropriate warning is enabled (should we check for
7494 -- Warnings (Off) on specific entities here, probably so???)
7496 and then Warn_On_Export_Import
7498 -- Exclude the VM case, since return of unconstrained arrays
7499 -- is properly handled in both the JVM and .NET cases.
7502 then
7503 Error_Msg_N
7510 -- If any of the formals for an exported foreign convention
7511 -- subprogram have defaults, then emit an appropriate warning since
7512 -- this is odd (default cannot be used from non-Ada code)
7517 if Warn_On_Export_Import
7519 then
7520 Error_Msg_N
7530 -- Pragma Inline_Always is disallowed for dispatching subprograms
7531 -- because the address of such subprograms is saved in the dispatch
7532 -- table to support dispatching calls, and dispatching calls cannot
7533 -- be inlined. This is consistent with the restriction against using
7534 -- 'Access or 'Address on an Inline_Always subprogram.
7538 then
7539 Error_Msg_N
7543 -- Because of the implicit representation of inherited predefined
7544 -- operators in the front-end, the overriding status of the operation
7545 -- may be affected when a full view of a type is analyzed, and this is
7546 -- not captured by the analysis of the corresponding type declaration.
7547 -- Therefore the correctness of a not-overriding indicator must be
7548 -- rechecked when the subprogram is frozen.
7552 then
7557 ----------------------
7558 -- Is_Fully_Defined --
7559 ----------------------
7562 begin
7571 then
7572 -- Verify that the record type has no components with private types
7573 -- without completion.
7575 declare
7578 begin
7590 -- For the designated type of an access to subprogram, all types in
7591 -- the profile must be fully defined.
7594 declare
7597 begin
7610 else
7616 ---------------------------------
7617 -- Process_Default_Expressions --
7618 ---------------------------------
7620 procedure Process_Default_Expressions
7623 is
7630 begin
7633 -- A subprogram instance and its associated anonymous subprogram share
7634 -- their signature. The default expression functions are defined in the
7635 -- wrapper packages for the anonymous subprogram, and should not be
7636 -- generated again for the instance.
7641 then
7649 -- We work with a copy of the default expression because we
7650 -- do not want to disturb the original, since this would mess
7651 -- up the conformance checking.
7655 -- The analysis of the expression may generate insert actions,
7656 -- which of course must not be executed. We wrap those actions
7657 -- in a procedure that is not called, and later on eliminated.
7658 -- The following cases have no side-effects, and are analyzed
7659 -- directly.
7663 N_Integer_Literal,
7664 N_Character_Literal,
7665 N_String_Literal,
7666 N_Real_Literal)
7670 then
7671 -- If there is no default function, we must still do a full
7672 -- analyze call on the default value, to ensure that all error
7673 -- checks are performed, e.g. those associated with static
7674 -- evaluation. Note: this branch will always be taken if the
7675 -- analyzer is turned off (but we still need the error checks).
7677 -- Note: the setting of parent here is to meet the requirement
7678 -- that we can only analyze the expression while attached to
7679 -- the tree. Really the requirement is that the parent chain
7680 -- be set, we don't actually need to be in the tree.
7685 -- Default expressions are resolved with their own type if the
7686 -- context is generic, to avoid anomalies with private types.
7690 else
7694 -- If that resolved expression will raise constraint error,
7695 -- then flag the default value as raising constraint error.
7696 -- This allows a proper error message on the calls.
7702 -- If the default is a parameterless call, we use the name of
7703 -- the called function directly, and there is no body to build.
7707 then
7710 -- Else construct and analyze the body of a wrapper procedure
7711 -- that contains an object declaration to hold the expression.
7712 -- Given that this is done only to complete the analysis, it
7713 -- simpler to build a procedure than a function which might
7714 -- involve secondary stack expansion.
7716 else
7719 Dbody :=
7721 Specification =>
7728 Object_Definition =>
7732 Handled_Statement_Sequence =>
7749 ----------------------------------------
7750 -- Set_Component_Alignment_If_Not_Set --
7751 ----------------------------------------
7754 begin
7755 -- Ignore if not base type, subtypes don't need anything
7761 -- Do not override existing representation
7772 else
7773 Set_Component_Alignment
7779 --------------------------
7780 -- Set_SSO_From_Default --
7781 --------------------------
7786 begin
7787 -- Set default SSO for an array or record base type, except in case of
7788 -- a type extension (which always inherits the SSO of its parent type).
7795 then
7796 Reversed :=
7798 or else
7803 -- For a record type, if bit order is specified explicitly,
7804 -- then do not set SSO from default if not consistent. Note that
7805 -- we do not want to look at a Bit_Order attribute definition
7806 -- for a parent: if we were to inherit Bit_Order, then both
7807 -- SSO_Set_*_By_Default flags would have been cleared already
7808 -- (by Inherit_Aspects_At_Freeze_Point).
7810 and then not
7812 and then
7815 then
7816 -- If flags cause reverse storage order, then set the result. Note
7817 -- that we would have ignored the pragma setting the non default
7818 -- storage order in any case, hence the assertion at this point.
7820 pragma Assert
7825 -- For a record type, also set reversed bit order. Note: if a bit
7826 -- order has been specified explicitly, then this is a no-op.
7835 ------------------
7836 -- Undelay_Type --
7837 ------------------
7840 begin
7844 -- Since we don't want T to have a Freeze_Node, we don't want its
7845 -- Full_View or Corresponding_Record_Type to have one either.
7847 -- ??? Fundamentally, this whole handling is unpleasant. What we really
7848 -- want is to be sure that for an Itype that's part of record R and is a
7849 -- subtype of type T, that it's frozen after the later of the freeze
7850 -- points of R and T. We have no way of doing that directly, so what we
7851 -- do is force most such Itypes to be frozen as part of freezing R via
7852 -- this procedure and only delay the ones that need to be delayed
7853 -- (mostly the designated types of access types that are defined as part
7854 -- of the record).
7860 then
7868 then
7873 ------------------
7874 -- Warn_Overlay --
7875 ------------------
7877 procedure Warn_Overlay
7881 is
7883 -- The object to which the address clause applies
7889 begin
7890 -- No warning if address clause overlay warnings are off
7896 -- No warning if there is an explicit initialization
7904 -- We only give the warning for non-imported entities of a type for
7905 -- which a non-null base init proc is defined, or for objects of access
7906 -- types with implicit null initialization, or when Normalize_Scalars
7907 -- applies and the type is scalar or a string type (the latter being
7908 -- tested for because predefined String types are initialized by inline
7909 -- code rather than by an init_proc). Note that we do not give the
7910 -- warning for Initialize_Scalars, since we suppressed initialization
7911 -- in this case. Also, do not warn if Suppress_Initialization is set.
7921 then
7924 then
7929 then
7936 then
7943 -- A function call (most likely to To_Address) is probably not an
7944 -- overlay, so skip warning. Ditto if the function call was inlined
7945 -- and transformed into an entity.
7953 -- If a pragma Import follows, we assume that it is for the current
7954 -- target of the address clause, and skip the warning.
7959 then
7965 Error_Msg_N
7967 Nam);
7968 else
7969 Error_Msg_N
7971 Nam);
7974 -- Add friendly warning if initialization comes from a packed array
7975 -- component.
7978 declare
7981 begin
7986 then
7990 then
7991 Error_Msg_NE
7996 else
8003 Error_Msg_N
8006 Nam);