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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) 1992-2015, 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
1801 -- Historical note: We used to create a finalization master for an
1802 -- access type whose designated type is not controlled, but contains
1803 -- private controlled compoments. This form of postprocessing is no
1804 -- longer needed because the finalization master is now created when
1805 -- the access type is frozen (see Exp_Ch3.Freeze_Type).
1811 -----------------------
1812 -- Freeze_And_Append --
1813 -----------------------
1815 procedure Freeze_And_Append
1819 is
1821 begin
1825 else
1831 -------------------
1832 -- Freeze_Before --
1833 -------------------
1838 begin
1848 -------------------
1849 -- Freeze_Entity --
1850 -------------------
1854 -- Save the current Ghost mode in effect in case the entity being frozen
1855 -- sets a different mode.
1865 -- This could use a comment ???
1868 -- Used to detect attempt to freeze function declared in another unit
1871 -- List of freezing actions, left at No_List if none
1874 -- This flag gets set to true for a variable with default initialization
1877 -- N is a freezing action to be appended to the Result
1880 -- If Loc is a freeze_entity that appears after the last declaration
1881 -- in the scope, inhibit error messages on late completion.
1884 -- Check that an Access or Unchecked_Access attribute with a prefix
1885 -- which is the current instance type can only be applied when the type
1886 -- is limited.
1889 -- Give warning for modulus of 8, 16, 32, or 64 given as an explicit
1890 -- integer literal without an explicit corresponding size clause. The
1891 -- caller has checked that Utype is a modular integer type.
1894 -- Freeze array type, including freezing index and component types
1897 -- Create Freeze_Generic_Entity nodes for types declared in a generic
1898 -- package. Recurse on inner generic packages.
1901 -- Freeze formals and return type of subprogram. If some type in the
1902 -- profile is a limited view, freezing of the entity will take place
1903 -- elsewhere, and the function returns False. This routine will be
1904 -- modified if and when we can implement AI05-019 efficiently ???
1907 -- Freeze record type, including freezing component types, and freezing
1908 -- primitive operations if this is a tagged type.
1911 -- Determine whether an arbitrary entity is subject to Boolean aspect
1912 -- Import and its value is specified as True.
1915 -- Following AI05-151, a function can return a limited view of a type
1916 -- declared elsewhere. In that case the function cannot be frozen at
1917 -- the end of its enclosing package. If its first use is in a different
1918 -- unit, it cannot be frozen there, but if the call is legal the full
1919 -- view of the return type is available and the subprogram can now be
1920 -- frozen. However the freeze node cannot be inserted at the point of
1921 -- call, but rather must go in the package holding the function, so that
1922 -- the backend can process it in the proper context.
1925 -- Restore the values of all saved global variables
1928 -- If E is an entity for an imported subprogram with pre/post-conditions
1929 -- then this procedure will create a wrapper to ensure that proper run-
1930 -- time checking of the pre/postconditions. See body for details.
1932 -------------------
1933 -- Add_To_Result --
1934 -------------------
1937 begin
1940 else
1945 ----------------------------
1946 -- After_Last_Declaration --
1947 ----------------------------
1952 begin
1958 else
1962 else
1967 ----------------------------
1968 -- Check_Current_Instance --
1969 ----------------------------
1974 -- Determine whether Typ is compatible with the rules for aliased
1975 -- views of types as defined in RM 3.10 in the various dialects.
1978 -- Process routine to apply check to given node
1980 -----------------------------
1981 -- Is_Aliased_View_Of_Type --
1982 -----------------------------
1987 begin
1988 -- Common case
1992 then
1995 -- The following paragraphs describe what a legal aliased view of
1996 -- a type is in the various dialects of Ada.
1998 -- Ada 95
2000 -- The current instance of a limited type, and a formal parameter
2001 -- or generic formal object of a tagged type.
2003 -- Ada 95 limited type
2004 -- * Type with reserved word "limited"
2005 -- * A protected or task type
2006 -- * A composite type with limited component
2011 -- Ada 2005
2013 -- The current instance of a limited tagged type, a protected
2014 -- type, a task type, or a type that has the reserved word
2015 -- "limited" in its full definition ... a formal parameter or
2016 -- generic formal object of a tagged type.
2018 -- Ada 2005 limited type
2019 -- * Type with reserved word "limited", "synchronized", "task"
2020 -- or "protected"
2021 -- * A composite type with limited component
2022 -- * A derived type whose parent is a non-interface limited type
2025 return
2027 or else
2032 -- Ada 2012 and beyond
2034 -- The current instance of an immutably limited type ... a formal
2035 -- parameter or generic formal object of a tagged type.
2037 -- Ada 2012 limited type
2038 -- * Type with reserved word "limited", "synchronized", "task"
2039 -- or "protected"
2040 -- * A composite type with limited component
2041 -- * A derived type whose parent is a non-interface limited type
2042 -- * An incomplete view
2044 -- Ada 2012 immutably limited type
2045 -- * Explicitly limited record type
2046 -- * Record extension with "limited" present
2047 -- * Non-formal limited private type that is either tagged
2048 -- or has at least one access discriminant with a default
2049 -- expression
2050 -- * Task type, protected type or synchronized interface
2051 -- * Type derived from immutably limited type
2053 else
2054 return
2060 -------------
2061 -- Process --
2062 -------------
2065 begin
2069 Name_Unchecked_Access)
2073 then
2075 Error_Msg_N
2078 else
2079 Error_Msg_N
2086 else
2096 -- Local variables
2101 -- Start of processing for Check_Current_Instance
2103 begin
2109 ------------------------------
2110 -- Check_Suspicious_Modulus --
2111 ------------------------------
2116 begin
2122 declare
2125 begin
2127 declare
2131 begin
2133 declare
2137 begin
2138 -- First case, modulus and size are the same. This
2139 -- happens if you have something like mod 32, with
2140 -- an explicit size of 32, this is for sure a case
2141 -- where the warning is given, since it is seems
2142 -- very unlikely that someone would want e.g. a
2143 -- five bit type stored in 32 bits. It is much
2144 -- more likely they wanted a 32-bit type.
2149 -- Second case, the modulus is 32 or 64 and no
2150 -- size clause is present. This is a less clear
2151 -- case for giving the warning, but in the case
2152 -- of 32/64 (5-bit or 6-bit types) these seem rare
2153 -- enough that it is a likely error (and in any
2154 -- case using 2**5 or 2**6 in these cases seems
2155 -- clearer. We don't include 8 or 16 here, simply
2156 -- because in practice 3-bit and 4-bit types are
2157 -- more common and too many false positives if
2158 -- we warn in these cases.
2162 then
2165 -- No warning needed
2167 else
2171 -- If we fall through, give warning
2174 Error_Msg_N
2176 Modulus);
2185 -----------------------
2186 -- Freeze_Array_Type --
2187 -----------------------
2195 -- Set true if any of the index types is an enumeration type with a
2196 -- non-standard representation.
2198 begin
2207 then
2214 -- Processing that is done only for base types
2218 -- Deal with default setting of reverse storage order
2222 -- Propagate flags for component type
2226 then
2234 -- Warn for pragma Pack overriding foreign convention
2238 then
2239 declare
2244 begin
2248 Error_Msg_N
2251 Error_Msg_N
2258 -- If packing was requested or if the component size was
2259 -- set explicitly, then see if bit packing is required. This
2260 -- processing is only done for base types, since all of the
2261 -- representation aspects involved are type-related.
2263 -- This is not just an optimization, if we start processing the
2264 -- subtypes, they interfere with the settings on the base type
2265 -- (this is because Is_Packed has a slightly different meaning
2266 -- before and after freezing).
2268 declare
2272 begin
2276 then
2285 else
2288 -- We can set the component size if it is less than 16,
2289 -- rounding it up to the next storage unit size.
2295 else
2299 -- Set component size up to match alignment if it would
2300 -- otherwise be less than the alignment. This deals with
2301 -- cases of types whose alignment exceeds their size (the
2302 -- padded type cases).
2305 declare
2307 begin
2315 -- Case of component size that may result in packing
2318 declare
2324 Get_Attribute_Definition_Clause
2327 begin
2328 -- Warn if we have pack and component size so that the
2329 -- pack is ignored.
2331 -- Note: here we must check for the presence of a
2332 -- component size before checking for a Pack pragma to
2333 -- deal with the case where the array type is a derived
2334 -- type whose parent is currently private.
2338 and then Warn_On_Redundant_Constructs
2339 then
2341 Error_Msg_NE
2343 Error_Msg_N
2349 -- Set component size if not already set by a component
2350 -- size clause.
2356 -- Check for base type of 8, 16, 32 bits, where an
2357 -- unsigned subtype has a length one less than the
2358 -- base type (e.g. Natural subtype of Integer).
2360 -- In such cases, if a component size was not set
2361 -- explicitly, then generate a warning.
2367 then
2371 Error_Msg_N
2373 Pack_Pragma);
2374 Error_Msg_N
2376 Pack_Pragma);
2380 -- Actual packing is not needed for 8, 16, 32, 64. Also
2381 -- not needed for 24 if alignment is 1.
2388 then
2389 -- Here the array was requested to be packed, but
2390 -- the packing request had no effect, so Is_Packed
2391 -- is reset.
2393 -- Note: semantically this means that we lose track
2394 -- of the fact that a derived type inherited a pragma
2395 -- Pack that was non- effective, but that seems fine.
2397 -- We regard a Pack pragma as a request to set a
2398 -- representation characteristic, and this request
2399 -- may be ignored.
2406 then
2410 -- In all other cases, packing is indeed needed
2412 else
2421 -- Check for Aliased or Atomic_Components/Atomic with unsuitable
2422 -- packing or explicit component size clause given.
2427 and then
2429 then
2433 -- Outputs error messages for incorrect CS clause or pragma
2434 -- Pack for aliased or atomic components (T is "aliased" or
2435 -- "atomic");
2437 -----------------
2438 -- Complain_CS --
2439 -----------------
2442 begin
2444 Clause :=
2445 Get_Attribute_Definition_Clause
2448 Error_Msg_N
2452 Error_Msg_N
2455 else
2456 Error_Msg_N
2462 -- Start of processing for Alias_Atomic_Check
2464 begin
2465 -- If object size of component type isn't known, we cannot
2466 -- be sure so we defer to the back end.
2471 -- Case where component size has no effect. First check for
2472 -- object size of component type multiple of the storage
2473 -- unit size.
2477 -- OK in both packing case and component size case if RM
2478 -- size is known and static and same as the object size.
2480 and then
2484 -- Or if we have an explicit component size clause and
2485 -- the component size and object size are equal.
2487 or else
2490 then
2497 then
2503 -- Warn for case of atomic type
2509 then
2510 Error_Msg_NE
2525 -- Check for scalar storage order
2527 declare
2529 begin
2530 Check_Component_Storage_Order
2533 ADC => Get_Attribute_Definition_Clause
2535 Attribute_Scalar_Storage_Order),
2539 -- Processing that is done only for subtypes
2541 else
2542 -- Acquire alignment from base type
2550 -- Specific checks for bit-packed arrays
2554 -- Check number of elements for bit packed arrays that come from
2555 -- source and have compile time known ranges. The bit-packed
2556 -- arrays circuitry does not support arrays with more than
2557 -- Integer'Last + 1 elements, and when this restriction is
2558 -- violated, causes incorrect data access.
2560 -- For the case where this is not compile time known, a run-time
2561 -- check should be generated???
2564 declare
2570 begin
2576 -- Never generate an error if any index is of a generic
2577 -- type. We will check this in instances.
2584 Ilen :=
2590 -- No attempt is made to check number of elements if not
2591 -- compile time known.
2604 then
2605 Error_Msg_N
2612 -- Check size
2615 declare
2619 begin
2620 -- It is not clear if it is possible to have no size clause
2621 -- at this stage, but it is not worth worrying about. Post
2622 -- error on the entity name in the size clause if present,
2623 -- else on the type entity itself.
2627 else
2634 -- If any of the index types was an enumeration type with a non-
2635 -- standard rep clause, then we indicate that the array type is
2636 -- always packed (even if it is not bit packed).
2645 -- If the array is packed, we must create the packed array type to be
2646 -- used to actually implement the type. This is only needed for real
2647 -- array types (not for string literal types, since they are present
2648 -- only for the front end).
2652 then
2656 -- Make sure that we have the necessary routines to implement the
2657 -- packing, and complain now if not. Note that we only test this
2658 -- for constrained array types.
2664 then
2665 declare
2669 begin
2672 then
2673 Error_Msg_CRT
2677 -- Cancel the packing
2687 -- Size information of packed array type is copied to the array
2688 -- type, since this is really the representation. But do not
2689 -- override explicit existing size values. If the ancestor subtype
2690 -- is constrained the Packed_Array_Impl_Type will be inherited
2691 -- from it, but the size may have been provided already, and
2692 -- must not be overridden either.
2695 and then
2698 then
2710 -- For non-packed arrays set the alignment of the array to the
2711 -- alignment of the component type if it is unknown. Skip this
2712 -- in atomic case (atomic arrays may need larger alignments).
2721 then
2726 -----------------------------
2727 -- Freeze_Generic_Entities --
2728 -----------------------------
2735 begin
2754 --------------------
2755 -- Freeze_Profile --
2756 --------------------
2763 begin
2764 -- Loop through formals
2770 -- AI05-0151: incomplete types can appear in a profile. By the
2771 -- time the entity is frozen, the full view must be available,
2772 -- unless it is a limited view.
2777 then
2789 then
2790 -- If the type of a formal is incomplete, subprogram is being
2791 -- frozen prematurely. Within an instance (but not within a
2792 -- wrapper package) this is an artifact of our need to regard
2793 -- the end of an instantiation as a freeze point. Otherwise it
2794 -- is a definite error.
2801 elsif not After_Last_Declaration
2802 and then not Freezing_Library_Level_Tagged_Type
2803 then
2805 Error_Msg
2810 -- Check suspicious parameter for C function. These tests apply
2811 -- only to exported/imported subprograms.
2813 if Warn_On_Export_Import
2816 or else
2823 then
2824 -- Qualify mention of formals with subprogram name
2828 -- Check suspicious use of fat C pointer
2832 then
2833 Error_Msg_N
2836 -- Check suspicious return of boolean
2843 then
2844 Error_Msg_N
2846 Error_Msg_N
2850 -- Check suspicious tagged type
2853 or else
2857 then
2858 Error_Msg_N
2862 -- Check wrong convention subprogram pointer
2866 then
2867 Error_Msg_N
2871 Error_Msg_NE
2876 -- Turn off name qualification after message output
2881 -- Check for unconstrained array in exported foreign convention
2882 -- case.
2888 and then Warn_On_Export_Import
2890 -- Exclude VM case, since both .NET and JVM can handle
2891 -- unconstrained arrays without a problem.
2894 then
2897 -- If this is an inherited operation, place the warning on
2898 -- the derived type declaration, rather than on the original
2899 -- subprogram.
2902 then
2908 else
2924 -- If the formal is an anonymous_access_to_subprogram
2925 -- freeze the subprogram type as well, to prevent
2926 -- scope anomalies in gigi, because there is no other
2927 -- clear point at which it could be frozen.
2931 then
2939 -- Case of function: similar checks on return type
2943 -- Check whether function is declared elsewhere.
2945 Late_Freezing :=
2950 -- Freeze return type
2954 -- AI05-0151: the return type may have been incomplete
2955 -- at the point of declaration. Replace it with the full
2956 -- view, unless the current type is a limited view. In
2957 -- that case the full view is in a different unit, and
2958 -- gigi finds the non-limited view after the other unit
2959 -- is elaborated.
2964 then
2968 -- If the return type is a limited view and the non-
2969 -- limited view is still incomplete, the function has
2970 -- to be frozen at a later time.
2974 and then
2976 then
2984 -- Check suspicious return type for C function
2986 if Warn_On_Export_Import
2988 or else
2991 then
2992 -- Check suspicious return of fat C pointer
2998 then
3002 -- Check suspicious return of boolean
3010 then
3011 declare
3014 begin
3015 Error_Msg_NE
3017 Error_Msg_NE
3022 -- Check suspicious return tagged type
3026 and then
3027 Is_Tagged_Type
3032 then
3036 -- Check return of wrong convention subprogram pointer
3042 then
3046 Error_Msg_NE
3052 -- Give warning for suspicious return of a result of an
3053 -- unconstrained array type in a foreign convention function.
3057 -- We are looking for a return of unconstrained array
3062 -- Exclude imported routines, the warning does not belong on
3063 -- the import, but rather on the routine definition.
3067 -- Exclude VM case, since both .NET and JVM can handle return
3068 -- of unconstrained arrays without a problem.
3072 -- Check that general warning is enabled, and that it is not
3073 -- suppressed for this particular case.
3075 and then Warn_On_Export_Import
3078 then
3087 ------------------------
3088 -- Freeze_Record_Type --
3089 ------------------------
3101 -- Set True if the record type scope Rec has been pushed on the scope
3102 -- stack. Needed for the analysis of delayed aspects specified to the
3103 -- components of Rec.
3106 -- Scalar_Storage_Order attribute definition clause for the record
3109 -- Set True if we find at least one component with no component
3110 -- clause (used to warn about useless Pack pragmas).
3113 -- Set True if we find at least one component with a component
3114 -- clause (used to warn about useless Bit_Order pragmas, and also
3115 -- to detect cases where Implicit_Packing may have an effect).
3118 -- Set True if we find at least one component which is aliased. This
3119 -- is used to prevent Implicit_Packing of the record, since packing
3120 -- cannot modify the size of alignment of an aliased component.
3123 -- Set True if we find at least one component whose type has a
3124 -- Scalar_Storage_Order attribute definition clause.
3127 -- Set False if we encounter a component of a non-scalar type
3131 -- Accumulates total RM_Size values and total Esize values of all
3132 -- scalar components. Used for processing of Implicit_Packing.
3135 -- If N is an allocator, possibly wrapped in one or more level of
3136 -- qualified expression(s), return the inner allocator node, else
3137 -- return Empty.
3140 -- If the component subtype is an access to a constrained subtype of
3141 -- an already frozen type, make the subtype frozen as well. It might
3142 -- otherwise be frozen in the wrong scope, and a freeze node on
3143 -- subtype has no effect. Similarly, if the component subtype is a
3144 -- regular (not protected) access to subprogram, set the anonymous
3145 -- subprogram type to frozen as well, to prevent an out-of-scope
3146 -- freeze node at some eventual point of call. Protected operations
3147 -- are handled elsewhere.
3150 -- Make sure that all types mentioned in Discrete_Choices of the
3151 -- variants referenceed by the Variant_Part VP are frozen. This is
3152 -- a recursive routine to deal with nested variants.
3154 ---------------------
3155 -- Check_Allocator --
3156 ---------------------
3160 begin
3162 loop
3167 else
3173 -----------------
3174 -- Check_Itype --
3175 -----------------
3180 begin
3183 then
3186 -- In addition, add an Itype_Reference to ensure that the
3187 -- access subtype is elaborated early enough. This cannot be
3188 -- done if the subtype may depend on discriminants.
3193 then
3201 then
3206 ------------------------------------
3207 -- Freeze_Choices_In_Variant_Part --
3208 ------------------------------------
3217 begin
3218 -- Loop through variants
3223 -- Loop through choices, checking that all types are frozen
3229 then
3236 -- Check for nested variant part to process
3250 -- Start of processing for Freeze_Record_Type
3252 begin
3253 -- Deal with delayed aspect specifications for components. The
3254 -- analysis of the aspect is required to be delayed to the freeze
3255 -- point, thus we analyze the pragma or attribute definition
3256 -- clause in the tree at this point. We also analyze the aspect
3257 -- specification node at the freeze point when the aspect doesn't
3258 -- correspond to pragma/attribute definition clause.
3264 then
3269 -- The visibility to the discriminants must be restored in
3270 -- order to properly analyze the aspects.
3283 -- Pop the scope if Rec scope has been pushed on the scope stack
3284 -- during the delayed aspect analysis process.
3291 Pop_Scope;
3294 -- Freeze components and embedded subtypes
3303 -- Handle the component and discriminant case
3306 declare
3309 begin
3310 -- Freezing a record type freezes the type of each of its
3311 -- components. However, if the type of the component is
3312 -- part of this record, we do not want or need a separate
3313 -- Freeze_Node. Note that Is_Itype is wrong because that's
3314 -- also set in private type cases. We also can't check for
3315 -- the Scope being exactly Rec because of private types and
3316 -- record extensions.
3321 then
3327 -- Warn for pragma Pack overriding foreign convention
3332 -- Don't warn for aliased components, since override
3333 -- cannot happen in that case.
3336 then
3337 declare
3342 begin
3346 Error_Msg_N
3348 PP);
3350 Error_Msg_NE
3357 -- Check for error of component clause given for variable
3358 -- sized type. We have to delay this test till this point,
3359 -- since the component type has to be frozen for us to know
3360 -- if it is variable length.
3365 -- We omit this test in a generic context, it will be
3366 -- applied at instantiation time.
3371 -- Also omit this test in CodePeer mode, since we do not
3372 -- have sufficient info on size and rep clauses.
3377 -- Omit check if component has a generic type. This can
3378 -- happen in an instantiation within a generic in ASIS
3379 -- mode, where we force freeze actions without full
3380 -- expansion.
3385 -- Do the check
3387 elsif not
3388 Size_Known_At_Compile_Time
3390 then
3391 Error_Msg_N
3396 else
3400 -- Case of component requires byte alignment
3404 -- Set the enclosing record to also require byte align
3408 -- Check for component clause that is inconsistent with
3409 -- the required byte boundary alignment.
3414 then
3415 Error_Msg_N
3423 -- Gather data for possible Implicit_Packing later. Note that at
3424 -- this stage we might be dealing with a real component, or with
3425 -- an implicit subtype declaration.
3429 else
3430 Scalar_Component_Total_RM_Size :=
3432 Scalar_Component_Total_Esize :=
3436 -- If the component is an Itype with Delayed_Freeze and is either
3437 -- a record or array subtype and its base type has not yet been
3438 -- frozen, we must remove this from the entity list of this record
3439 -- and put it on the entity list of the scope of its base type.
3440 -- Note that we know that this is not the type of a component
3441 -- since we cleared Has_Delayed_Freeze for it in the previous
3442 -- loop. Thus this must be the Designated_Type of an access type,
3443 -- which is the type of a component.
3451 then
3452 declare
3456 begin
3457 -- We have a difficult case to handle here. Suppose Rec is
3458 -- subtype being defined in a subprogram that's created as
3459 -- part of the freezing of Rec'Base. In that case, we know
3460 -- that Comp'Base must have already been frozen by the time
3461 -- we get to elaborate this because Gigi doesn't elaborate
3462 -- any bodies until it has elaborated all of the declarative
3463 -- part. But Is_Frozen will not be set at this point because
3464 -- we are processing code in lexical order.
3466 -- We detect this case by going up the Scope chain of Rec
3467 -- and seeing if we have a subprogram scope before reaching
3468 -- the top of the scope chain or that of Comp'Base. If we
3469 -- do, then mark that Comp'Base will actually be frozen. If
3470 -- so, we merely undelay it.
3487 else
3490 else
3494 -- Insert in entity list of scope of base type (which
3495 -- must be an enclosing scope, because still unfrozen).
3501 -- If the component is an access type with an allocator as default
3502 -- value, the designated type will be frozen by the corresponding
3503 -- expression in init_proc. In order to place the freeze node for
3504 -- the designated type before that for the current record type,
3505 -- freeze it now.
3507 -- Same process if the component is an array of access types,
3508 -- initialized with an aggregate. If the designated type is
3509 -- private, it cannot contain allocators, and it is premature
3510 -- to freeze the type, so we check for this as well.
3515 then
3516 declare
3520 begin
3523 -- If component is pointer to a class-wide type, freeze
3524 -- the specific type in the expression being allocated.
3525 -- The expression may be a subtype indication, in which
3526 -- case freeze the subtype mark.
3528 if Is_Class_Wide_Type
3530 then
3532 Freeze_And_Append
3536 then
3537 Freeze_And_Append
3545 else
3546 Freeze_And_Append
3554 then
3557 -- Freeze the designated type when initializing a component with
3558 -- an aggregate in case the aggregate contains allocators.
3560 -- type T is ...;
3561 -- type T_Ptr is access all T;
3562 -- type T_Array is array ... of T_Ptr;
3564 -- type Rec is record
3565 -- Comp : T_Array := (others => ...);
3566 -- end record;
3570 then
3571 declare
3574 Designated_Type
3577 begin
3578 -- The only case when this sort of freezing is not done is
3579 -- when the designated type is class-wide and the root type
3580 -- is the record owning the component. This scenario results
3581 -- in a circularity because the class-wide type requires
3582 -- primitives that have not been created yet as the root
3583 -- type is in the process of being frozen.
3585 -- type Rec is tagged;
3586 -- type Rec_Ptr is access all Rec'Class;
3587 -- type Rec_Array is array ... of Rec_Ptr;
3589 -- type Rec is record
3590 -- Comp : Rec_Array := (others => ...);
3591 -- end record;
3595 then
3603 then
3613 -- Deal with default setting of reverse storage order
3617 -- Check consistent attribute setting on component types
3619 SSO_ADC := Get_Attribute_Definition_Clause
3622 declare
3624 begin
3627 Check_Component_Storage_Order
3637 -- Now deal with reverse storage order/bit order issues
3641 -- Check compatibility of Scalar_Storage_Order with Bit_Order, if
3642 -- the former is specified.
3646 -- Note: report error on Rec, not on SSO_ADC, as ADC may apply
3647 -- to some ancestor type.
3650 Error_Msg_N
3655 -- Warn if there is an Scalar_Storage_Order attribute definition
3656 -- clause but no component clause, no component that itself has
3657 -- such an attribute definition, and no pragma Pack.
3660 or else
3661 SSO_ADC_Component
3662 or else
3664 then
3665 Error_Msg_N
3667 SSO_ADC);
3671 -- Deal with Bit_Order aspect
3679 then
3680 -- Warn if clause has no effect when no component clause is
3681 -- present, but suppress warning if the Bit_Order is required
3682 -- due to the presence of a Scalar_Storage_Order attribute.
3684 Error_Msg_N
3686 Error_Msg_N
3689 -- Here is where we do the processing to adjust component clauses
3690 -- for reversed bit order, when not using reverse SSO.
3694 then
3697 -- Case where we have both an explicit Bit_Order and the same
3698 -- Scalar_Storage_Order: leave record untouched, the back-end
3699 -- will take care of required layout conversions.
3701 else
3707 -- Complete error checking on record representation clause (e.g.
3708 -- overlap of components). This is called after adjusting the
3709 -- record for reverse bit order.
3711 declare
3713 begin
3719 -- Set OK_To_Reorder_Components depending on debug flags
3723 or else
3725 then
3730 -- Check for useless pragma Pack when all components placed. We only
3731 -- do this check for record types, not subtypes, since a subtype may
3732 -- have all its components placed, and it still makes perfectly good
3733 -- sense to pack other subtypes or the parent type. We do not give
3734 -- this warning if Optimize_Alignment is set to Space, since the
3735 -- pragma Pack does have an effect in this case (it always resets
3736 -- the alignment to one).
3740 and then not Unplaced_Component
3742 then
3743 -- Reset packed status. Probably not necessary, but we do it so
3744 -- that there is no chance of the back end doing something strange
3745 -- with this redundant indication of packing.
3749 -- Give warning if redundant constructs warnings on
3752 Error_Msg_N -- CODEFIX
3758 -- If this is the record corresponding to a remote type, freeze the
3759 -- remote type here since that is what we are semantically freezing.
3760 -- This prevents the freeze node for that type in an inner scope.
3767 -- Check for controlled components and unchecked unions.
3772 -- Do not set Has_Controlled_Component on a class-wide
3773 -- equivalent type. See Make_CW_Equivalent_Type.
3776 and then
3778 or else
3781 or else
3783 and then
3785 and then
3786 Has_Controlled_Component
3788 then
3796 -- Scan component declaration for likely misuses of current
3797 -- instance, either in a constraint or a default expression.
3807 -- Enforce the restriction that access attributes with a current
3808 -- instance prefix can only apply to limited types. This comment
3809 -- is floating here, but does not seem to belong here???
3811 -- Set component alignment if not otherwise already set
3815 -- For first subtypes, check if there are any fixed-point fields with
3816 -- component clauses, where we must check the size. This is not done
3817 -- till the freeze point since for fixed-point types, we do not know
3818 -- the size until the type is frozen. Similar processing applies to
3819 -- bit packed arrays.
3827 then
3828 Check_Size
3832 Junk);
3839 -- Generate warning for applying C or C++ convention to a record
3840 -- with discriminants. This is suppressed for the unchecked union
3841 -- case, since the whole point in this case is interface C. We also
3842 -- do not generate this within instantiations, since we will have
3843 -- generated a message on the template.
3848 or else
3851 and then not In_Instance
3854 then
3855 declare
3859 begin
3864 Error_Msg_N
3866 A2);
3867 else
3868 Error_Msg_N
3870 A2);
3873 Error_Msg_NE
3879 -- See if Size is too small as is (and implicit packing might help)
3883 -- No implicit packing if even one component is explicitly placed
3885 and then not Placed_Component
3887 -- Or even one component is aliased
3889 and then not Aliased_Component
3891 -- Must have size clause and all scalar components
3894 and then All_Scalar_Components
3896 -- Do not try implicit packing on records with discriminants, too
3897 -- complicated, especially in the variant record case.
3901 -- We can implicitly pack if the specified size of the record is
3902 -- less than the sum of the object sizes (no point in packing if
3903 -- this is not the case).
3907 -- And the total RM size cannot be greater than the specified size
3908 -- since otherwise packing will not get us where we have to be.
3912 -- Never do implicit packing in CodePeer or SPARK modes since
3913 -- we don't do any packing in these modes, since this generates
3914 -- over-complex code that confuses static analysis, and in
3915 -- general, neither CodePeer not GNATprove care about the
3916 -- internal representation of objects.
3919 then
3920 -- If implicit packing enabled, do it
3925 -- Otherwise flag the size clause
3927 else
3928 declare
3930 begin
3931 Error_Msg_NE -- CODEFIX
3933 Error_Msg_N -- CODEFIX
3940 -- The following checks are only relevant when SPARK_Mode is on as
3941 -- they are not standard Ada legality rules.
3946 -- A discriminated type cannot be effectively volatile
3947 -- (SPARK RM C.6(4)).
3952 -- A tagged type cannot be effectively volatile
3953 -- (SPARK RM C.6(5)).
3959 -- A non-effectively volatile record type cannot contain
3960 -- effectively volatile components (SPARK RM C.6(2)).
3962 else
3967 then
3969 Error_Msg_N
3979 -- All done if not a full record definition
3985 -- Finally we need to check the variant part to make sure that
3986 -- all types within choices are properly frozen as part of the
3987 -- freezing of the record type.
3994 begin
3995 -- Find component list
4007 then
4012 -- Case of variant part present
4018 -- Note: we used to call Check_Choices here, but it is too early,
4019 -- since predicated subtypes are frozen here, but their freezing
4020 -- actions are in Analyze_Freeze_Entity, which has not been called
4021 -- yet for entities frozen within this procedure, so we moved that
4022 -- call to the Analyze_Freeze_Entity for the record type.
4026 -- Check that all the primitives of an interface type are abstract
4027 -- or null procedures.
4031 then
4032 declare
4036 begin
4043 -- Avoid reporting the error on inherited primitives
4046 then
4051 Error_Msg_N
4055 else
4056 Error_Msg_N
4068 -------------------------------
4069 -- Has_Boolean_Aspect_Import --
4070 -------------------------------
4077 begin
4083 -- The value of aspect Import is True when the expression is
4084 -- either missing or it is explicitly set to True.
4090 then
4101 ----------------------------
4102 -- Late_Freeze_Subprogram --
4103 ----------------------------
4110 begin
4113 else
4120 ---------------------
4121 -- Restore_Globals --
4122 ---------------------
4125 begin
4129 ------------------------------
4130 -- Wrap_Imported_Subprogram --
4131 ------------------------------
4133 -- The issue here is that our normal approach of checking preconditions
4134 -- and postconditions does not work for imported procedures, since we
4135 -- are not generating code for the body. To get around this we create
4136 -- a wrapper, as shown by the following example:
4138 -- procedure K (A : Integer);
4139 -- pragma Import (C, K);
4141 -- The spec is rewritten by removing the effects of pragma Import, but
4142 -- leaving the convention unchanged, as though the source had said:
4144 -- procedure K (A : Integer);
4145 -- pragma Convention (C, K);
4147 -- and we create a body, added to the entity K freeze actions, which
4148 -- looks like:
4150 -- procedure K (A : Integer) is
4151 -- procedure K (A : Integer);
4152 -- pragma Import (C, K);
4153 -- begin
4154 -- K (A);
4155 -- end K;
4157 -- Now the contract applies in the normal way to the outer procedure,
4158 -- and the inner procedure has no contracts, so there is no problem
4159 -- in just calling it to get the original effect.
4161 -- In the case of a function, we create an appropriate return statement
4162 -- for the subprogram body that calls the inner procedure.
4174 begin
4175 -- Nothing to do if not imported
4180 -- Test enabling conditions for wrapping
4185 and then not GNATprove_Mode
4186 then
4187 -- Here we do the wrap
4189 -- Note on calls to Copy_Separate_Tree. The trees we are copying
4190 -- here are fully analyzed, but we definitely want fully syntactic
4191 -- unanalyzed trees in the body we construct, so that the analysis
4192 -- generates the right visibility, and that is exactly what the
4193 -- calls to Copy_Separate_Tree give us.
4195 -- Acquire copy of Inline pragma, and indicate that it does not
4196 -- come from an aspect, as it applies to an internal entity.
4201 -- Fix up spec to be not imported any more
4208 -- Grab the subprogram declaration and specification
4212 -- Build parameter list that we need
4221 -- Build the call
4224 Stmt :=
4226 Expression =>
4231 else
4232 Stmt :=
4238 -- Now build the body
4240 Bod :=
4242 Specification =>
4246 Specification =>
4248 Iprag),
4249 Handled_Statement_Sequence =>
4254 -- Append the body to freeze result
4259 -- Case of imported subprogram that does not get wrapped
4261 else
4262 -- Set Is_Public. All imported entities need an external symbol
4263 -- created for them since they are always referenced from another
4264 -- object file. Note this used to be set when we set Is_Imported
4265 -- back in Sem_Prag, but now we delay it to this point, since we
4266 -- don't want to set this flag if we wrap an imported subprogram.
4272 -- Start of processing for Freeze_Entity
4274 begin
4275 -- The entity being frozen may be subject to pragma Ghost with policy
4276 -- Ignore. Set the mode now to ensure that any nodes generated during
4277 -- freezing are properly flagged as ignored Ghost.
4281 -- We are going to test for various reasons why this entity need not be
4282 -- frozen here, but in the case of an Itype that's defined within a
4283 -- record, that test actually applies to the record.
4289 then
4293 -- Do not freeze if already frozen since we only need one freeze node
4296 Restore_Globals;
4299 -- It is improper to freeze an external entity within a generic because
4300 -- its freeze node will appear in a non-valid context. The entity will
4301 -- be frozen in the proper scope after the current generic is analyzed.
4302 -- However, aspects must be analyzed because they may be queried later
4303 -- within the generic itself, and the corresponding pragma or attribute
4304 -- definition has not been analyzed yet.
4311 Restore_Globals;
4314 -- AI05-0213: A formal incomplete type does not freeze the actual. In
4315 -- the instance, the same applies to the subtype renaming the actual.
4321 then
4322 Restore_Globals;
4325 -- Formal subprograms are never frozen
4328 Restore_Globals;
4331 -- Generic types are never frozen as they lack delayed semantic checks
4334 Restore_Globals;
4337 -- Do not freeze a global entity within an inner scope created during
4338 -- expansion. A call to subprogram E within some internal procedure
4339 -- (a stream attribute for example) might require freezing E, but the
4340 -- freeze node must appear in the same declarative part as E itself.
4341 -- The two-pass elaboration mechanism in gigi guarantees that E will
4342 -- be frozen before the inner call is elaborated. We exclude constants
4343 -- from this test, because deferred constants may be frozen early, and
4344 -- must be diagnosed (e.g. in the case of a deferred constant being used
4345 -- in a default expression). If the enclosing subprogram comes from
4346 -- source, or is a generic instance, then the freeze point is the one
4347 -- mandated by the language, and we freeze the entity. A subprogram that
4348 -- is a child unit body that acts as a spec does not have a spec that
4349 -- comes from source, but can only come from source.
4354 then
4355 declare
4358 begin
4365 then
4367 else
4368 Restore_Globals;
4377 -- Similarly, an inlined instance body may make reference to global
4378 -- entities, but these references cannot be the proper freezing point
4379 -- for them, and in the absence of inlining freezing will take place in
4380 -- their own scope. Normally instance bodies are analyzed after the
4381 -- enclosing compilation, and everything has been frozen at the proper
4382 -- place, but with front-end inlining an instance body is compiled
4383 -- before the end of the enclosing scope, and as a result out-of-order
4384 -- freezing must be prevented.
4386 elsif Front_End_Inlining
4387 and then In_Instance_Body
4389 then
4390 declare
4393 begin
4398 else
4404 Restore_Globals;
4412 Restore_Globals;
4416 -- Add checks to detect proper initialization of scalars that may appear
4417 -- as subprogram parameters.
4423 -- Deal with delayed aspect specifications. The analysis of the aspect
4424 -- is required to be delayed to the freeze point, thus we analyze the
4425 -- pragma or attribute definition clause in the tree at this point. We
4426 -- also analyze the aspect specification node at the freeze point when
4427 -- the aspect doesn't correspond to pragma/attribute definition clause.
4433 -- Here to freeze the entity
4437 -- Case of entity being frozen is other than a type
4441 -- If entity is exported or imported and does not have an external
4442 -- name, now is the time to provide the appropriate default name.
4443 -- Skip this if the entity is stubbed, since we don't need a name
4444 -- for any stubbed routine. For the case on intrinsics, if no
4445 -- external name is specified, then calls will be handled in
4446 -- Exp_Intr.Expand_Intrinsic_Call, and no name is needed. If an
4447 -- external name is provided, then Expand_Intrinsic_Call leaves
4448 -- calls in place for expansion by GIGI.
4454 then
4455 Set_Encoded_Interface_Name
4458 -- If entity is an atomic object appearing in a declaration and
4459 -- the expression is an aggregate, assign it to a temporary to
4460 -- ensure that the actual assignment is done atomically rather
4461 -- than component-wise (the assignment to the temp may be done
4462 -- component-wise, but that is harmless).
4469 then
4473 -- Subprogram case
4477 -- Check for needing to wrap imported subprogram
4481 -- Freeze all parameter types and the return type (RM 13.14(14)).
4482 -- However skip this for internal subprograms. This is also where
4483 -- any extra formal parameters are created since we now know
4484 -- whether the subprogram will use a foreign convention.
4486 -- In Ada 2012, freezing a subprogram does not always freeze
4487 -- the corresponding profile (see AI05-019). An attribute
4488 -- reference is not a freezing point of the profile.
4489 -- Other constructs that should not freeze ???
4491 -- This processing doesn't apply to internal entities (see below)
4495 Restore_Globals;
4500 -- Must freeze its parent first if it is a derived subprogram
4506 -- We don't freeze internal subprograms, because we don't normally
4507 -- want addition of extra formals or mechanism setting to happen
4508 -- for those. However we do pass through predefined dispatching
4509 -- cases, since extra formals may be needed in some cases, such as
4510 -- for the stream 'Input function (build-in-place formals).
4514 then
4520 Restore_Globals;
4524 -- If warning on suspicious contracts then check for the case of
4525 -- a postcondition other than False for a No_Return subprogram.
4528 and then Warn_On_Suspicious_Contract
4530 then
4531 declare
4535 begin
4538 Name_Postcondition,
4539 Name_Refined_Post)
4540 then
4541 Exp :=
4542 Expression
4547 then
4548 Error_Msg_NE
4559 -- Here for other than a subprogram or type
4561 else
4562 -- If entity has a type, and it is not a generic unit, then
4563 -- freeze it first (RM 13.14(10)).
4567 then
4570 -- For an object of an anonymous array type, aspects on the
4571 -- object declaration apply to the type itself. This is the
4572 -- case for Atomic_Components, Volatile_Components, and
4573 -- Independent_Components. In these cases analysis of the
4574 -- generated pragma will mark the anonymous types accordingly,
4575 -- and the object itself does not require a freeze node.
4581 then
4588 -- Special processing for objects created by object declaration
4592 -- Abstract type allowed only for C++ imported variables or
4593 -- constants.
4595 -- Note: we inhibit this check for objects that do not come
4596 -- from source because there is at least one case (the
4597 -- expansion of x'Class'Input where x is abstract) where we
4598 -- legitimately generate an abstract object.
4604 then
4609 Error_Msg_NE
4614 Error_Msg_N -- CODEFIX
4620 -- For object created by object declaration, perform required
4621 -- categorization (preelaborate and pure) checks. Defer these
4622 -- checks to freeze time since pragma Import inhibits default
4623 -- initialization and thus pragma Import affects these checks.
4627 -- If there is an address clause, check that it is valid
4631 -- Reset Is_True_Constant for non-constant aliased object. We
4632 -- consider that the fact that a non-constant object is aliased
4633 -- may indicate that some funny business is going on, e.g. an
4634 -- aliased object is passed by reference to a procedure which
4635 -- captures the address of the object, which is later used to
4636 -- assign a new value, even though the compiler thinks that
4637 -- it is not modified. Such code is highly dubious, but we
4638 -- choose to make it "work" for non-constant aliased objects.
4639 -- Note that we used to do this for all aliased objects,
4640 -- whether or not constant, but this caused anomalies down
4641 -- the line because we ended up with static objects that
4642 -- were not Is_True_Constant. Not resetting Is_True_Constant
4643 -- for (aliased) constant objects ensures that this anomaly
4644 -- never occurs.
4646 -- However, we don't do that for internal entities. We figure
4647 -- that if we deliberately set Is_True_Constant for an internal
4648 -- entity, e.g. a dispatch table entry, then we mean it.
4653 then
4657 -- If the object needs any kind of default initialization, an
4658 -- error must be issued if No_Default_Initialization applies.
4659 -- The check doesn't apply to imported objects, which are not
4660 -- ever default initialized, and is why the check is deferred
4661 -- until freezing, at which point we know if Import applies.
4662 -- Deferred constants are also exempted from this test because
4663 -- their completion is explicit, or through an import pragma.
4667 then
4673 and then
4678 or else
4681 then
4683 Check_Restriction
4687 -- Check that a Thread_Local_Storage variable does not have
4688 -- default initialization, and any explicit initialization must
4689 -- either be the null constant or a static constant.
4692 declare
4694 begin
4695 if Has_Default_Initialization
4696 or else
4698 and then
4700 or else not
4702 or else
4704 then
4705 Error_Msg_NE
4708 Error_Msg_NE
4715 -- For imported objects, set Is_Public unless there is also an
4716 -- address clause, which means that there is no external symbol
4717 -- needed for the Import (Is_Public may still be set for other
4718 -- unrelated reasons). Note that we delayed this processing
4719 -- till freeze time so that we can be sure not to set the flag
4720 -- if there is an address clause. If there is such a clause,
4721 -- then the only purpose of the Import pragma is to suppress
4722 -- implicit initialization.
4728 -- For source objects that are not Imported and are library
4729 -- level, if no linker section pragma was given inherit the
4730 -- appropriate linker section from the corresponding type.
4736 then
4737 Set_Linker_Section_Pragma
4741 -- For convention C objects of an enumeration type, warn if
4742 -- the size is not integer size and no explicit size given.
4743 -- Skip warning for Boolean, and Character, assume programmer
4744 -- expects 8-bit sizes for these cases.
4747 or else
4754 then
4756 Error_Msg_N
4758 E);
4763 -- Check that a constant which has a pragma Volatile[_Components]
4764 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
4766 -- Note: Atomic[_Components] also sets Volatile[_Components]
4772 then
4773 -- Make sure we actually have a pragma, and have not merely
4774 -- inherited the indication from elsewhere (e.g. an address
4775 -- clause, which is not good enough in RM terms).
4778 or else
4780 then
4781 Error_Msg_N
4786 or else
4788 then
4789 Error_Msg_N
4795 -- Static objects require special handling
4799 then
4803 -- Remaining step is to layout objects
4807 then
4811 -- For an object that does not have delayed freezing, and whose
4812 -- initialization actions have been captured in a compound
4813 -- statement, move them back now directly within the enclosing
4814 -- statement sequence.
4818 then
4823 -- Case of a type or subtype being frozen
4825 else
4826 -- We used to check here that a full type must have preelaborable
4827 -- initialization if it completes a private type specified with
4828 -- pragma Preelaborable_Initialization, but that missed cases where
4829 -- the types occur within a generic package, since the freezing
4830 -- that occurs within a containing scope generally skips traversal
4831 -- of a generic unit's declarations (those will be frozen within
4832 -- instances). This check was moved to Analyze_Package_Specification.
4834 -- The type may be defined in a generic unit. This can occur when
4835 -- freezing a generic function that returns the type (which is
4836 -- defined in a parent unit). It is clearly meaningless to freeze
4837 -- this type. However, if it is a subtype, its size may be determi-
4838 -- nable and used in subsequent checks, so might as well try to
4839 -- compute it.
4841 -- In Ada 2012, Freeze_Entities is also used in the front end to
4842 -- trigger the analysis of aspect expressions, so in this case we
4843 -- want to continue the freezing process.
4847 and then
4850 then
4852 Restore_Globals;
4856 -- Check for error of Type_Invariant'Class applied to an untagged
4857 -- type (check delayed to freeze time when full type is available).
4859 declare
4861 begin
4865 then
4866 Error_Msg_NE
4869 Error_Msg_N
4874 -- A Ghost type cannot be effectively volatile (SPARK RM 6.9(8))
4878 then
4882 -- Deal with special cases of freezing for subtype
4886 -- Before we do anything else, a specialized test for the case of
4887 -- a size given for an array where the array needs to be packed,
4888 -- but was not so the size cannot be honored. This is the case
4889 -- where implicit packing may apply. The reason we do this so
4890 -- early is that if we have implicit packing, the layout of the
4891 -- base type is affected, so we must do this before we freeze
4892 -- the base type.
4894 -- We could do this processing only if implicit packing is enabled
4895 -- since in all other cases, the error would be caught by the back
4896 -- end. However, we choose to do the check even if we do not have
4897 -- implicit packing enabled, since this allows us to give a more
4898 -- useful error message (advising use of pragmas Implicit_Packing
4899 -- or Pack).
4902 declare
4913 -- Number of elements in array
4915 begin
4916 -- Check enabling conditions. These are straightforward
4917 -- except for the test for a limited composite type. This
4918 -- eliminates the rare case of a array of limited components
4919 -- where there are issues of whether or not we can go ahead
4920 -- and pack the array (since we can't freely pack and unpack
4921 -- arrays if they are limited).
4923 -- Note that we check the root type explicitly because the
4924 -- whole point is we are doing this test before we have had
4925 -- a chance to freeze the base type (and it is that freeze
4926 -- action that causes stuff to be inherited).
4939 then
4940 -- Compute number of elements in array
4948 and then
4950 then
4954 Num_Elmts :=
4955 Num_Elmts *
4961 -- What we are looking for here is the situation where
4962 -- the RM_Size given would be exactly right if there was
4963 -- a pragma Pack (resulting in the component size being
4964 -- the same as the RM_Size). Furthermore, the component
4965 -- type size must be an odd size (not a multiple of
4966 -- storage unit). If the component RM size is an exact
4967 -- number of storage units that is a power of two, the
4968 -- array is not packed and has a standard representation.
4972 then
4973 -- For implicit packing mode, just set the component
4974 -- size silently.
4982 -- Otherwise give an error message
4984 else
4985 Error_Msg_NE
4987 Error_Msg_N -- CODEFIX
4993 and then Implicit_Packing
4994 and then
4996 or else
4998 or else
5000 then
5001 -- Not a packed array, but indicate the desired
5002 -- component size, for the back-end.
5012 -- If ancestor subtype present, freeze that first. Note that this
5013 -- will also get the base type frozen. Need RM reference ???
5020 -- No ancestor subtype present
5022 else
5023 -- See if we have a nearest ancestor that has a predicate.
5024 -- That catches the case of derived type with a predicate.
5025 -- Need RM reference here ???
5033 -- Freeze base type before freezing the entity (RM 13.14(15))
5040 -- A subtype inherits all the type-related representation aspects
5041 -- from its parents (RM 13.1(8)).
5045 -- For a derived type, freeze its parent type first (RM 13.14(15))
5051 -- A derived type inherits each type-related representation aspect
5052 -- of its parent type that was directly specified before the
5053 -- declaration of the derived type (RM 13.1(15)).
5058 -- Check for incompatible size and alignment for record type
5060 if Warn_On_Size_Alignment
5064 -- If explicit Object_Size clause given assume that the programmer
5065 -- knows what he is doing, and expects the compiler behavior.
5069 -- Check for size not a multiple of alignment
5072 then
5073 declare
5079 begin
5082 -- Give a warning
5086 Error_Msg_NE
5092 else
5094 Error_Msg_NE
5107 -- Array type
5112 -- For a class-wide type, the corresponding specific type is
5113 -- frozen as well (RM 13.14(15))
5118 -- If the base type of the class-wide type is still incomplete,
5119 -- the class-wide remains unfrozen as well. This is legal when
5120 -- E is the formal of a primitive operation of some other type
5121 -- which is being frozen.
5125 Restore_Globals;
5129 -- The equivalent type associated with a class-wide subtype needs
5130 -- to be frozen to ensure that its layout is done.
5134 then
5138 -- Generate an itype reference for a library-level class-wide type
5139 -- at the freeze point. Otherwise the first explicit reference to
5140 -- the type may appear in an inner scope which will be rejected by
5141 -- the back-end.
5145 then
5146 declare
5149 begin
5152 -- From a gigi point of view, a class-wide subtype derives
5153 -- from its record equivalent type. As a result, the itype
5154 -- reference must appear after the freeze node of the
5155 -- equivalent type or gigi will reject the reference.
5159 then
5161 else
5167 -- For a record type or record subtype, freeze all component types
5168 -- (RM 13.14(15)). We test for E_Record_(sub)Type here, rather than
5169 -- using Is_Record_Type, because we don't want to attempt the freeze
5170 -- for the case of a private type with record extension (we will do
5171 -- that later when the full type is frozen).
5176 then
5179 -- For a concurrent type, freeze corresponding record type. This does
5180 -- not correspond to any specific rule in the RM, but the record type
5181 -- is essentially part of the concurrent type. Also freeze all local
5182 -- entities. This includes record types created for entry parameter
5183 -- blocks and whatever local entities may appear in the private part.
5197 -- The guard on the presence of the Etype seems to be needed
5198 -- for some CodePeer (-gnatcC) cases, but not clear why???
5203 then
5214 -- Private types are required to point to the same freeze node as
5215 -- their corresponding full views. The freeze node itself has to
5216 -- point to the partial view of the entity (because from the partial
5217 -- view, we can retrieve the full view, but not the reverse).
5218 -- However, in order to freeze correctly, we need to freeze the full
5219 -- view. If we are freezing at the end of a scope (or within the
5220 -- scope) of the private type, the partial and full views will have
5221 -- been swapped, the full view appears first in the entity chain and
5222 -- the swapping mechanism ensures that the pointers are properly set
5223 -- (on scope exit).
5225 -- If we encounter the partial view before the full view (e.g. when
5226 -- freezing from another scope), we freeze the full view, and then
5227 -- set the pointers appropriately since we cannot rely on swapping to
5228 -- fix things up (subtypes in an outer scope might not get swapped).
5230 -- If the full view is itself private, the above requirements apply
5231 -- to the underlying full view instead of the full view. But there is
5232 -- no swapping mechanism for the underlying full view so we need to
5233 -- set the pointers appropriately in both cases.
5237 then
5238 -- The construction of the dispatch table associated with library
5239 -- level tagged types forces freezing of all the primitives of the
5240 -- type, which may cause premature freezing of the partial view.
5241 -- For example:
5243 -- package Pkg is
5244 -- type T is tagged private;
5245 -- type DT is new T with private;
5246 -- procedure Prim (X : in out T; Y : in out DT'Class);
5247 -- private
5248 -- type T is tagged null record;
5249 -- Obj : T;
5250 -- type DT is new T with null record;
5251 -- end;
5253 -- In this case the type will be frozen later by the usual
5254 -- mechanism: an object declaration, an instantiation, or the
5255 -- end of a declarative part.
5259 then
5261 Restore_Globals;
5264 -- Case of full view present
5268 -- If full view has already been frozen, then no further
5269 -- processing is required
5275 -- Otherwise freeze full view and patch the pointers so that
5276 -- the freeze node will elaborate both views in the back end.
5277 -- However, if full view is itself private, freeze underlying
5278 -- full view instead and patch the pointers so that the freeze
5279 -- node will elaborate the three views in the back end.
5281 else
5282 declare
5285 begin
5288 then
5296 then
5303 else
5316 else
5317 -- {Incomplete,Private}_Subtypes with Full_Views
5318 -- constrained by discriminants.
5329 -- AI-117 requires that the convention of a partial view be the
5330 -- same as the convention of the full view. Note that this is a
5331 -- recognized breach of privacy, but it's essential for logical
5332 -- consistency of representation, and the lack of a rule in
5333 -- RM95 was an oversight.
5340 -- Size information is copied from the full view to the
5341 -- incomplete or private view for consistency.
5343 -- We skip this is the full view is not a type. This is very
5344 -- strange of course, and can only happen as a result of
5345 -- certain illegalities, such as a premature attempt to derive
5346 -- from an incomplete type.
5353 Restore_Globals;
5356 -- Case of underlying full view present
5360 then
5365 -- Patch the pointers so that the freeze node will elaborate
5366 -- both views in the back end.
5375 else
5383 Restore_Globals;
5386 -- Case of no full view present. If entity is derived or subtype,
5387 -- it is safe to freeze, correctness depends on the frozen status
5388 -- of parent. Otherwise it is either premature usage, or a Taft
5389 -- amendment type, so diagnosis is at the point of use and the
5390 -- type might be frozen later.
5395 else
5397 Restore_Globals;
5401 -- For access subprogram, freeze types of all formals, the return
5402 -- type was already frozen, since it is the Etype of the function.
5403 -- Formal types can be tagged Taft amendment types, but otherwise
5404 -- they cannot be incomplete.
5412 then
5416 -- AI05-151: Incomplete types are allowed in access to
5417 -- subprogram specifications.
5420 Error_Msg_NE
5431 -- For access to a protected subprogram, freeze the equivalent type
5432 -- (however this is not set if we are not generating code or if this
5433 -- is an anonymous type used just for resolution).
5441 -- Generic types are never seen by the back-end, and are also not
5442 -- processed by the expander (since the expander is turned off for
5443 -- generic processing), so we never need freeze nodes for them.
5446 Restore_Globals;
5450 -- Some special processing for non-generic types to complete
5451 -- representation details not known till the freeze point.
5456 -- Some error checks required for ordinary fixed-point type. Defer
5457 -- these till the freeze-point since we need the small and range
5458 -- values. We only do these checks for base types
5463 Error_Msg_N
5468 Error_Msg_N
5474 Error_Msg_N
5480 Error_Msg_N
5492 and then Warn_On_Suspicious_Modulus_Value
5493 then
5497 -- The pool applies to named and anonymous access types, but not
5498 -- to subprogram and to internal types generated for 'Access
5499 -- references.
5504 then
5505 -- If a pragma Default_Storage_Pool applies, and this type has no
5506 -- Storage_Pool or Storage_Size clause (which must have occurred
5507 -- before the freezing point), then use the default. This applies
5508 -- only to base types.
5510 -- None of this applies to access to subprograms, for which there
5511 -- are clearly no pools.
5517 then
5518 -- Case of pragma Default_Storage_Pool (null)
5523 -- Case of pragma Default_Storage_Pool (storage_pool_NAME)
5525 else
5530 -- Check restriction for standard storage pool
5536 -- Deal with error message for pure access type. This is not an
5537 -- error in Ada 2005 if there is no pool (see AI-366).
5543 then
5547 Error_Msg_N
5551 Error_Msg_N
5554 else
5555 Error_Msg_N
5562 -- Case of composite types
5566 -- AI-117 requires that all new primitives of a tagged type must
5567 -- inherit the convention of the full view of the type. Inherited
5568 -- and overriding operations are defined to inherit the convention
5569 -- of their parent or overridden subprogram (also specified in
5570 -- AI-117), which will have occurred earlier (in Derive_Subprogram
5571 -- and New_Overloaded_Entity). Here we set the convention of
5572 -- primitives that are still convention Ada, which will ensure
5573 -- that any new primitives inherit the type's convention. Class-
5574 -- wide types can have a foreign convention inherited from their
5575 -- specific type, but are excluded from this since they don't have
5576 -- any associated primitives.
5581 then
5582 declare
5586 begin
5598 -- If the type is a simple storage pool type, then this is where
5599 -- we attempt to locate and validate its Allocate, Deallocate, and
5600 -- Storage_Size operations (the first is required, and the latter
5601 -- two are optional). We also verify that the full type for a
5602 -- private type is allowed to be a simple storage pool type.
5606 then
5607 -- If the type is marked Has_Private_Declaration, then this is
5608 -- a full type for a private type that was specified with the
5609 -- pragma Simple_Storage_Pool_Type, and here we ensure that the
5610 -- pragma is allowed for the full type (for example, it can't
5611 -- be an array type, or a nonlimited record type).
5616 then
5618 Error_Msg_N
5629 procedure Validate_Simple_Pool_Op_Formal
5636 -- Validate one formal Pool_Op_Formal of the candidate pool
5637 -- operation Pool_Op. The formal must be of Expected_Type
5638 -- and have mode Expected_Mode. OK_Formal will be set to
5639 -- False if the formal doesn't match. If OK_Formal is False
5640 -- on entry, then the formal will effectively be ignored
5641 -- (because validation of the pool op has already failed).
5642 -- Upon return, Pool_Op_Formal will be updated to the next
5643 -- formal, if any.
5645 procedure Validate_Simple_Pool_Operation
5647 -- Search for and validate a simple pool operation with the
5648 -- name Op_Name. If the name is Allocate, then there must be
5649 -- exactly one such primitive operation for the simple pool
5650 -- type. If the name is Deallocate or Storage_Size, then
5651 -- there can be at most one such primitive operation. The
5652 -- profile of the located primitive must conform to what
5653 -- is expected for each operation.
5655 ------------------------------------
5656 -- Validate_Simple_Pool_Op_Formal --
5657 ------------------------------------
5659 procedure Validate_Simple_Pool_Op_Formal
5666 is
5667 begin
5668 -- If OK_Formal is False on entry, then simply ignore
5669 -- the formal, because an earlier formal has already
5670 -- been flagged.
5675 -- If no formal is passed in, then issue an error for a
5676 -- missing formal.
5679 Error_Msg_NE
5689 -- If the pool type was expected for this formal, then
5690 -- this will not be considered a candidate operation
5691 -- for the simple pool, so we unset OK_Formal so that
5692 -- the op and any later formals will be ignored.
5699 else
5700 Error_Msg_NE
5707 -- Issue error if formal's mode is not the expected one
5710 Error_Msg_N
5712 Pool_Op_Formal);
5715 -- Advance to the next formal
5720 ------------------------------------
5721 -- Validate_Simple_Pool_Operation --
5722 ------------------------------------
5724 procedure Validate_Simple_Pool_Operation
5726 is
5732 begin
5733 pragma Assert
5735 Name_Deallocate,
5736 Name_Storage_Size));
5740 -- For each homonym declared immediately in the scope
5741 -- of the simple storage pool type, determine whether
5742 -- the homonym is an operation of the pool type, and,
5743 -- if so, check that its profile is as expected for
5744 -- a simple pool operation of that name.
5750 then
5755 -- The first parameter must be of the pool type
5756 -- in order for the operation to qualify.
5759 Validate_Simple_Pool_Op_Formal
5762 else
5763 Validate_Simple_Pool_Op_Formal
5768 -- If another operation with this name has already
5769 -- been located for the type, then flag an error,
5770 -- since we only allow the type to have a single
5771 -- such primitive.
5774 Error_Msg_NE
5779 -- In the case of Allocate and Deallocate, a formal
5780 -- of type System.Address is required.
5783 Validate_Simple_Pool_Op_Formal
5788 Validate_Simple_Pool_Op_Formal
5793 -- In the case of Allocate and Deallocate, formals
5794 -- of type Storage_Count are required as the third
5795 -- and fourth parameters.
5798 Validate_Simple_Pool_Op_Formal
5801 Validate_Simple_Pool_Op_Formal
5806 -- If no mismatched formals have been found (Is_OK)
5807 -- and no excess formals are present, then this
5808 -- operation has been validated, so record it.
5818 -- There must be a valid Allocate operation for the type,
5819 -- so issue an error if none was found.
5823 then
5829 -- Simple pool operations can't be abstract
5832 Error_Msg_N
5837 -- The Storage_Size operation must be a function with
5838 -- Storage_Count as its result type.
5842 Error_Msg_N
5846 Error_Msg_NE
5851 -- Allocate and Deallocate must be procedures
5854 Error_Msg_N
5860 -- Start of processing for Validate_Simple_Pool_Ops
5862 begin
5870 -- Now that all types from which E may depend are frozen, see if the
5871 -- size is known at compile time, if it must be unsigned, or if
5872 -- strict alignment is required
5881 -- Do not allow a size clause for a type which does not have a size
5882 -- that is known at compile time
5886 then
5887 -- Suppress this message if errors posted on E, even if we are
5888 -- in all errors mode, since this is often a junk message
5891 Error_Msg_N
5897 -- Now we set/verify the representation information, in particular
5898 -- the size and alignment values. This processing is not required for
5899 -- generic types, since generic types do not play any part in code
5900 -- generation, and so the size and alignment values for such types
5901 -- are irrelevant. Ditto for types declared within a generic unit,
5902 -- which may have components that depend on generic parameters, and
5903 -- that will be recreated in an instance.
5908 -- Otherwise we call the layout procedure
5910 else
5914 -- If this is an access to subprogram whose designated type is itself
5915 -- a subprogram type, the return type of this anonymous subprogram
5916 -- type must be decorated as well.
5920 then
5924 -- If the type has a Defaut_Value/Default_Component_Value aspect,
5925 -- this is where we analye the expression (after the type is frozen,
5926 -- since in the case of Default_Value, we are analyzing with the
5927 -- type itself, and we treat Default_Component_Value similarly for
5928 -- the sake of uniformity).
5931 declare
5936 begin
5941 else
5952 Flag_Non_Static_Expr
5959 -- End of freeze processing for type entities
5962 -- Here is where we logically freeze the current entity. If it has a
5963 -- freeze node, then this is the point at which the freeze node is
5964 -- linked into the result list.
5968 -- If a freeze node is already allocated, use it, otherwise allocate
5969 -- a new one. The preallocation happens in the case of anonymous base
5970 -- types, where we preallocate so that we can set First_Subtype_Link.
5971 -- Note that we reset the Sloc to the current freeze location.
5977 else
5988 -- A final pass over record types with discriminants. If the type
5989 -- has an incomplete declaration, there may be constrained access
5990 -- subtypes declared elsewhere, which do not depend on the discrimi-
5991 -- nants of the type, and which are used as component types (i.e.
5992 -- the full view is a recursive type). The designated types of these
5993 -- subtypes can only be elaborated after the type itself, and they
5994 -- need an itype reference.
5998 then
5999 declare
6004 begin
6014 then
6026 -- When a type is frozen, the first subtype of the type is frozen as
6027 -- well (RM 13.14(15)). This has to be done after freezing the type,
6028 -- since obviously the first subtype depends on its own base type.
6033 -- If we just froze a tagged non-class wide record, then freeze the
6034 -- corresponding class-wide type. This must be done after the tagged
6035 -- type itself is frozen, because the class-wide type refers to the
6036 -- tagged type which generates the class.
6041 then
6048 -- Special handling for subprograms
6052 -- If subprogram has address clause then reset Is_Public flag, since
6053 -- we do not want the backend to generate external references.
6057 then
6062 Restore_Globals;
6066 -----------------------------
6067 -- Freeze_Enumeration_Type --
6068 -----------------------------
6071 begin
6072 -- By default, if no size clause is present, an enumeration type with
6073 -- Convention C is assumed to interface to a C enum, and has integer
6074 -- size. This applies to types. For subtypes, verify that its base
6075 -- type has no size clause either. Treat other foreign conventions
6076 -- in the same way, and also make sure alignment is set right.
6083 -- Don't do this if Short_Enums on target
6085 and then not Target_Short_Enums
6086 then
6090 -- Normal Ada case or size clause present or not Long_C_Enums on target
6092 else
6093 -- If the enumeration type interfaces to C, and it has a size clause
6094 -- that specifies less than int size, it warrants a warning. The
6095 -- user may intend the C type to be an enum or a char, so this is
6096 -- not by itself an error that the Ada compiler can detect, but it
6097 -- it is a worth a heads-up. For Boolean and Character types we
6098 -- assume that the programmer has the proper C type in mind.
6106 -- Don't do this if Short_Enums on target
6108 and then not Target_Short_Enums
6109 then
6110 Error_Msg_N
6118 -----------------------
6119 -- Freeze_Expression --
6120 -----------------------
6131 -- This flag is set true if the entity must be frozen outside the
6132 -- current subprogram. This happens in the case of expander generated
6133 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
6134 -- not freeze all entities like other bodies, but which nevertheless
6135 -- may reference entities that have to be frozen before the body and
6136 -- obviously cannot be frozen inside the body.
6139 -- If the expression is an array aggregate, the type of the component
6140 -- expressions is also frozen. If the component type is an access type
6141 -- and the expressions include allocators, the designed type is frozen
6142 -- as well.
6145 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
6146 -- it is the handled statement sequence of an expander-generated
6147 -- subprogram (init proc, stream subprogram, or renaming as body).
6148 -- If so, this is not a freezing context.
6150 -----------------------------------------
6151 -- Find_Aggregate_Component_Desig_Type --
6152 -----------------------------------------
6158 begin
6184 ----------------------
6185 -- In_Expanded_Body --
6186 ----------------------
6192 begin
6195 else
6202 else
6205 -- The following are expander-created bodies, or bodies that
6206 -- are not freeze points.
6215 N_Subprogram_Renaming_Declaration,
6216 N_Expression_Function))
6217 then
6219 else
6225 -- Start of processing for Freeze_Expression
6227 begin
6228 -- Immediate return if freezing is inhibited. This flag is set by the
6229 -- analyzer to stop freezing on generated expressions that would cause
6230 -- freezing if they were in the source program, but which are not
6231 -- supposed to freeze, since they are created.
6237 -- If expression is non-static, then it does not freeze in a default
6238 -- expression, see section "Handling of Default Expressions" in the
6239 -- spec of package Sem for further details. Note that we have to make
6240 -- sure that we actually have a real expression (if we have a subtype
6241 -- indication, we can't test Is_OK_Static_Expression). However, we
6242 -- exclude the case of the prefix of an attribute of a static scalar
6243 -- subtype from this early return, because static subtype attributes
6244 -- should always cause freezing, even in default expressions, but
6245 -- the attribute may not have been marked as static yet (because in
6246 -- Resolve_Attribute, the call to Eval_Attribute follows the call of
6247 -- Freeze_Expression on the prefix).
6249 if In_Spec_Exp
6256 then
6260 -- Freeze type of expression if not frozen already
6268 -- Base type may be an derived numeric type that is frozen at
6269 -- the point of declaration, but first_subtype is still unfrozen.
6276 -- For entity name, freeze entity if not frozen already. A special
6277 -- exception occurs for an identifier that did not come from source.
6278 -- We don't let such identifiers freeze a non-internal entity, i.e.
6279 -- an entity that did come from source, since such an identifier was
6280 -- generated by the expander, and cannot have any semantic effect on
6281 -- the freezing semantics. For example, this stops the parameter of
6282 -- an initialization procedure from freezing the variable.
6289 then
6296 else
6300 -- For an allocator freeze designated type if not frozen already
6302 -- For an aggregate whose component type is an access type, freeze the
6303 -- designated type now, so that its freeze does not appear within the
6304 -- loop that might be created in the expansion of the aggregate. If the
6305 -- designated type is a private type without full view, the expression
6306 -- cannot contain an allocator, so the type is not frozen.
6308 -- For a function, we freeze the entity when the subprogram declaration
6309 -- is frozen, but a function call may appear in an initialization proc.
6310 -- before the declaration is frozen. We need to generate the extra
6311 -- formals, if any, to ensure that the expansion of the call includes
6312 -- the proper actuals. This only applies to Ada subprograms, not to
6313 -- imported ones.
6324 then
6326 -- Check whether aggregate includes allocators.
6331 when N_Selected_Component |
6332 N_Indexed_Component |
6333 N_Slice =>
6344 then
6355 then
6359 -- All done if nothing needs freezing
6364 then
6368 -- Examine the enclosing context by climbing the parent chain. The
6369 -- traversal serves two purposes - to detect scenarios where freezeing
6370 -- is not needed and to find the proper insertion point for the freeze
6371 -- nodes. Although somewhat similar to Insert_Actions, this traversal
6372 -- is freezing semantics-sensitive. Inserting freeze nodes blindly in
6373 -- the tree may result in types being frozen too early.
6376 loop
6379 -- If we don't have a parent, then we are not in a well-formed tree.
6380 -- This is an unusual case, but there are some legitimate situations
6381 -- in which this occurs, notably when the expressions in the range of
6382 -- a type declaration are resolved. We simply ignore the freeze
6383 -- request in this case. Is this right ???
6389 -- See if we have got to an appropriate point in the tree
6393 -- A special test for the exception of (RM 13.14(8)) for the case
6394 -- of per-object expressions (RM 3.8(18)) occurring in component
6395 -- definition or a discrete subtype definition. Note that we test
6396 -- for a component declaration which includes both cases we are
6397 -- interested in, and furthermore the tree does not have explicit
6398 -- nodes for either of these two constructs.
6402 -- The case we want to test for here is an identifier that is
6403 -- a per-object expression, this is either a discriminant that
6404 -- appears in a context other than the component declaration
6405 -- or it is a reference to the type of the enclosing construct.
6407 -- For either of these cases, we skip the freezing
6409 if not In_Spec_Expression
6412 then
6413 -- We recognize the discriminant case by just looking for
6414 -- a reference to a discriminant. It can only be one for
6415 -- the enclosing construct. Skip freezing in this case.
6420 -- For the case of a reference to the enclosing record,
6421 -- (or task or protected type), we look for a type that
6422 -- matches the current scope.
6429 -- If we have an enumeration literal that appears as the choice in
6430 -- the aggregate of an enumeration representation clause, then
6431 -- freezing does not occur (RM 13.14(10)).
6435 -- The case we are looking for is an enumeration literal
6439 then
6440 -- If enumeration literal appears directly as the choice,
6441 -- do not freeze (this is the normal non-overloaded case)
6445 then
6448 -- If enumeration literal appears as the name of function
6449 -- which is the choice, then also do not freeze. This
6450 -- happens in the overloaded literal case, where the
6451 -- enumeration literal is temporarily changed to a function
6452 -- call for overloading analysis purposes.
6455 and then
6457 and then
6459 then
6464 -- Normally if the parent is a handled sequence of statements,
6465 -- then the current node must be a statement, and that is an
6466 -- appropriate place to insert a freeze node.
6470 -- An exception occurs when the sequence of statements is for
6471 -- an expander generated body that did not do the usual freeze
6472 -- all operation. In this case we usually want to freeze
6473 -- outside this body, not inside it, and we skip past the
6474 -- subprogram body that we are inside.
6477 declare
6481 begin
6482 -- Freeze the entity only when it is declared inside the
6483 -- body of the expander generated procedure. This case
6484 -- is recognized by the scope of the entity or its type,
6485 -- which is either the spec for some enclosing body, or
6486 -- (in the case of init_procs, for which there are no
6487 -- separate specs) the current scope.
6493 or else
6495 then
6501 then
6506 -- An expression function may act as a completion of
6507 -- a function declaration. As such, it can reference
6508 -- entities declared between the two views:
6510 -- Hidden []; -- 1
6511 -- function F return ...;
6512 -- private
6513 -- function Hidden return ...;
6514 -- function F return ... is (Hidden); -- 2
6516 -- Refering to the example above, freezing the expression
6517 -- of F (2) would place Hidden's freeze node (1) in the
6518 -- wrong place. Avoid explicit freezing and let the usual
6519 -- scenarios do the job - for example, reaching the end
6520 -- of the private declarations, or a call to F.
6523 N_Expression_Function
6524 then
6527 -- Freeze outside the body
6529 else
6535 -- Here if normal case where we are in handled statement
6536 -- sequence and want to do the insertion right there.
6538 else
6542 -- If parent is a body or a spec or a block, then the current node
6543 -- is a statement or declaration and we can insert the freeze node
6544 -- before it.
6546 when N_Block_Statement |
6547 N_Entry_Body |
6548 N_Package_Body |
6549 N_Package_Specification |
6550 N_Protected_Body |
6551 N_Subprogram_Body |
6554 -- The expander is allowed to define types in any statements list,
6555 -- so any of the following parent nodes also mark a freezing point
6556 -- if the actual node is in a list of statements or declarations.
6558 when N_Abortable_Part |
6559 N_Accept_Alternative |
6560 N_And_Then |
6561 N_Case_Statement_Alternative |
6562 N_Compilation_Unit_Aux |
6563 N_Conditional_Entry_Call |
6564 N_Delay_Alternative |
6565 N_Elsif_Part |
6566 N_Entry_Call_Alternative |
6567 N_Exception_Handler |
6568 N_Extended_Return_Statement |
6569 N_Freeze_Entity |
6570 N_If_Statement |
6571 N_Or_Else |
6572 N_Selective_Accept |
6573 N_Triggering_Alternative =>
6577 -- Freeze nodes produced by an expression coming from the Actions
6578 -- list of a N_Expression_With_Actions node must remain within the
6579 -- Actions list. Inserting the freeze nodes further up the tree
6580 -- may lead to use before declaration issues in the case of array
6581 -- types.
6586 then
6590 -- Note: N_Loop_Statement is a special case. A type that appears
6591 -- in the source can never be frozen in a loop (this occurs only
6592 -- because of a loop expanded by the expander), so we keep on
6593 -- going. Otherwise we terminate the search. Same is true of any
6594 -- entity which comes from source. (if they have predefined type,
6595 -- that type does not appear to come from source, but the entity
6596 -- should not be frozen here).
6602 -- For all other cases, keep looking at parents
6608 -- We fall through the case if we did not yet find the proper
6609 -- place in the free for inserting the freeze node, so climb.
6614 -- If the expression appears in a record or an initialization procedure,
6615 -- the freeze nodes are collected and attached to the current scope, to
6616 -- be inserted and analyzed on exit from the scope, to insure that
6617 -- generated entities appear in the correct scope. If the expression is
6618 -- a default for a discriminant specification, the scope is still void.
6619 -- The expression can also appear in the discriminant part of a private
6620 -- or concurrent type.
6622 -- If the expression appears in a constrained subcomponent of an
6623 -- enclosing record declaration, the freeze nodes must be attached to
6624 -- the outer record type so they can eventually be placed in the
6625 -- enclosing declaration list.
6627 -- The other case requiring this special handling is if we are in a
6628 -- default expression, since in that case we are about to freeze a
6629 -- static type, and the freeze scope needs to be the outer scope, not
6630 -- the scope of the subprogram with the default parameter.
6632 -- For default expressions and other spec expressions in generic units,
6633 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
6634 -- placing them at the proper place, after the generic unit.
6637 or else Freeze_Outside
6642 then
6643 declare
6648 begin
6661 -- The current scope may be that of a constrained component of
6662 -- an enclosing record declaration, or of a loop of an enclosing
6663 -- quantified expression, which is above the current scope in the
6664 -- scope stack. Indeed in the context of a quantified expression,
6665 -- a scope is created and pushed above the current scope in order
6666 -- to emulate the loop-like behavior of the quantified expression.
6667 -- If the expression is within a top-level pragma, as for a pre-
6668 -- condition on a library-level subprogram, nothing to do.
6673 N_Quantified_Expression)
6674 then
6681 Freeze_Nodes;
6682 else
6692 -- Now we have the right place to do the freezing. First, a special
6693 -- adjustment, if we are in spec-expression analysis mode, these freeze
6694 -- actions must not be thrown away (normally all inserted actions are
6695 -- thrown away in this mode. However, the freeze actions are from static
6696 -- expressions and one of the important reasons we are doing this
6697 -- special analysis is to get these freeze actions. Therefore we turn
6698 -- off the In_Spec_Expression mode to propagate these freeze actions.
6699 -- This also means they get properly analyzed and expanded.
6703 -- Freeze the designated type of an allocator (RM 13.14(13))
6709 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
6710 -- the enumeration representation clause exception in the loop above.
6716 -- Freeze name if one is present (RM 13.14(11))
6722 -- Restore In_Spec_Expression flag
6727 -----------------------------
6728 -- Freeze_Fixed_Point_Type --
6729 -----------------------------
6731 -- Certain fixed-point types and subtypes, including implicit base types
6732 -- and declared first subtypes, have not yet set up a range. This is
6733 -- because the range cannot be set until the Small and Size values are
6734 -- known, and these are not known till the type is frozen.
6736 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
6737 -- whose bounds are unanalyzed real literals. This routine will recognize
6738 -- this case, and transform this range node into a properly typed range
6739 -- with properly analyzed and resolved values.
6756 -- Save original bounds (for shaving tests)
6759 -- Actual size chosen
6762 -- Returns size of type with given bounds. Also leaves these
6763 -- bounds set as the current bounds of the Typ.
6765 -----------
6766 -- Fsize --
6767 -----------
6770 begin
6776 -- Start of processing for Freeze_Fixed_Point_Type
6778 begin
6779 -- If Esize of a subtype has not previously been set, set it now
6786 else
6791 -- Immediate return if the range is already analyzed. This means that
6792 -- the range is already set, and does not need to be computed by this
6793 -- routine.
6799 -- Immediate return if either of the bounds raises Constraint_Error
6803 then
6813 -- Ordinary fixed-point case
6817 -- For the ordinary fixed-point case, we are allowed to fudge the
6818 -- end-points up or down by small. Generally we prefer to fudge up,
6819 -- i.e. widen the bounds for non-model numbers so that the end points
6820 -- are included. However there are cases in which this cannot be
6821 -- done, and indeed cases in which we may need to narrow the bounds.
6822 -- The following circuit makes the decision.
6824 -- Note: our terminology here is that Incl_EP means that the bounds
6825 -- are widened by Small if necessary to include the end points, and
6826 -- Excl_EP means that the bounds are narrowed by Small to exclude the
6827 -- end-points if this reduces the size.
6829 -- Note that in the Incl case, all we care about is including the
6830 -- end-points. In the Excl case, we want to narrow the bounds as
6831 -- much as permitted by the RM, to give the smallest possible size.
6848 begin
6849 -- First step. Base types are required to be symmetrical. Right
6850 -- now, the base type range is a copy of the first subtype range.
6851 -- This will be corrected before we are done, but right away we
6852 -- need to deal with the case where both bounds are non-negative.
6853 -- In this case, we set the low bound to the negative of the high
6854 -- bound, to make sure that the size is computed to include the
6855 -- required sign. Note that we do not need to worry about the
6856 -- case of both bounds negative, because the sign will be dealt
6857 -- with anyway. Furthermore we can't just go making such a bound
6858 -- symmetrical, since in a twos-complement system, there is an
6859 -- extra negative value which could not be accommodated on the
6860 -- positive side.
6865 then
6870 -- Compute the fudged bounds. If the number is a model number,
6871 -- then we do nothing to include it, but we are allowed to backoff
6872 -- to the next adjacent model number when we exclude it. If it is
6873 -- not a model number then we straddle the two values with the
6874 -- model numbers on either side.
6880 else
6884 -- The low value excluding the end point is Small greater, but
6885 -- we do not do this exclusion if the low value is positive,
6886 -- since it can't help the size and could actually hurt by
6887 -- crossing the high bound.
6892 -- If the value went from negative to zero, then we have the
6893 -- case where Loval_Incl_EP is the model number just below
6894 -- zero, so we want to stick to the negative value for the
6895 -- base type to maintain the condition that the size will
6896 -- include signed values.
6900 then
6904 else
6908 -- Similar processing for upper bound and high value
6914 else
6920 else
6924 -- One further adjustment is needed. In the case of subtypes, we
6925 -- cannot go outside the range of the base type, or we get
6926 -- peculiarities, and the base type range is already set. This
6927 -- only applies to the Incl values, since clearly the Excl values
6928 -- are already as restricted as they are allowed to be.
6935 -- Get size including and excluding end points
6940 -- No need to exclude end-points if it does not reduce size
6950 -- Now we set the actual size to be used. We want to use the
6951 -- bounds fudged up to include the end-points but only if this
6952 -- can be done without violating a specifically given size
6953 -- size clause or causing an unacceptable increase in size.
6955 -- Case of size clause given
6959 -- Use the inclusive size only if it is consistent with
6960 -- the explicitly specified size.
6967 -- If the inclusive size is too large, we try excluding
6968 -- the end-points (will be caught later if does not work).
6970 else
6976 -- Case of size clause not given
6978 else
6979 -- If we have a base type whose corresponding first subtype
6980 -- has an explicit size that is large enough to include our
6981 -- end-points, then do so. There is no point in working hard
6982 -- to get a base type whose size is smaller than the specified
6983 -- size of the first subtype.
6989 then
6994 -- If excluding the end-points makes the size smaller and
6995 -- results in a size of 8,16,32,64, then we take the smaller
6996 -- size. For the 64 case, this is compulsory. For the other
6997 -- cases, it seems reasonable. We like to include end points
6998 -- if we can, but not at the expense of moving to the next
6999 -- natural boundary of size.
7003 then
7008 -- Otherwise we can definitely include the end points
7010 else
7016 -- One pathological case: normally we never fudge a low bound
7017 -- down, since it would seem to increase the size (if it has
7018 -- any effect), but for ranges containing single value, or no
7019 -- values, the high bound can be small too large. Consider:
7021 -- type t is delta 2.0**(-14)
7022 -- range 131072.0 .. 0;
7024 -- That lower bound is *just* outside the range of 32 bits, and
7025 -- does need fudging down in this case. Note that the bounds
7026 -- will always have crossed here, since the high bound will be
7027 -- fudged down if necessary, as in the case of:
7029 -- type t is delta 2.0**(-14)
7030 -- range 131072.0 .. 131072.0;
7032 -- So we detect the situation by looking for crossed bounds,
7033 -- and if the bounds are crossed, and the low bound is greater
7034 -- than zero, we will always back it off by small, since this
7035 -- is completely harmless.
7042 -- And of course, we need to do exactly the same parallel
7043 -- fudge for flat ranges in the negative region.
7056 -- For the decimal case, none of this fudging is required, since there
7057 -- are no end-point problems in the decimal case (the end-points are
7058 -- always included).
7060 else
7064 -- At this stage, the actual size has been calculated and the proper
7065 -- required bounds are stored in the low and high bounds.
7069 Error_Msg_N
7071 Typ);
7075 -- Check size against explicit given size
7081 Error_Msg_NE
7085 else
7089 -- Increase size to next natural boundary if no size clause given
7091 else
7098 else
7106 -- If we have a base type, then expand the bounds so that they extend to
7107 -- the full width of the allocated size in bits, to avoid junk range
7108 -- checks on intermediate computations.
7115 -- Final step is to reanalyze the bounds using the proper type
7116 -- and set the Corresponding_Integer_Value fields of the literals.
7122 -- Resolve with universal fixed if the base type, and the base type if
7123 -- it is a subtype. Note we can't resolve the base type with itself,
7124 -- that would be a reference before definition.
7128 else
7132 -- Set corresponding integer value for bound
7134 Set_Corresponding_Integer_Value
7137 -- Similar processing for high bound
7145 else
7149 Set_Corresponding_Integer_Value
7152 -- Set type of range to correspond to bounds
7156 -- Set Esize to calculated size if not set already
7162 -- Set RM_Size if not already set. If already set, check value
7164 declare
7167 begin
7172 Error_Msg_NE
7177 else
7182 -- Check for shaving
7186 Error_Msg_N
7188 Error_Msg_N
7193 Error_Msg_N
7195 Error_Msg_N
7201 ------------------
7202 -- Freeze_Itype --
7203 ------------------
7208 begin
7217 --------------------------
7218 -- Freeze_Static_Object --
7219 --------------------------
7224 -- Exception raised if the type of a static object cannot be made
7225 -- static. This happens if the type depends on non-global objects.
7228 -- Called to ensure that an expression used as part of a type definition
7229 -- is statically allocatable, which means that the expression type is
7230 -- statically allocatable, and the expression is either static, or a
7231 -- reference to a library level constant.
7234 -- Called to mark a type as static, checking that it is possible
7235 -- to set the type as static. If it is not possible, then the
7236 -- exception Cannot_Be_Static is raised.
7238 -----------------------------
7239 -- Ensure_Expression_Is_SA --
7240 -----------------------------
7245 begin
7257 then
7265 -----------------------
7266 -- Ensure_Type_Is_SA --
7267 -----------------------
7273 begin
7274 -- If type is library level, we are all set
7280 -- We are also OK if the type already marked as statically allocated,
7281 -- which means we processed it before.
7287 -- Mark type as statically allocated
7291 -- Check that it is safe to statically allocate this type
7309 declare
7313 begin
7325 else
7334 then
7353 else
7358 -- Start of processing for Freeze_Static_Object
7360 begin
7363 exception
7366 -- If the object that cannot be static is imported or exported, then
7367 -- issue an error message saying that this object cannot be imported
7368 -- or exported. If it has an address clause it is an overlay in the
7369 -- current partition and the static requirement is not relevant.
7370 -- Do not issue any error message when ignoring rep clauses.
7377 Error_Msg_N
7381 -- Otherwise must be exported, something is wrong if compiler
7382 -- is marking something as statically allocated which cannot be).
7385 Error_Msg_N
7390 -----------------------
7391 -- Freeze_Subprogram --
7392 -----------------------
7398 begin
7399 -- Subprogram may not have an address clause unless it is imported
7403 Error_Msg_N
7410 -- Reset the Pure indication on an imported subprogram unless an
7411 -- explicit Pure_Function pragma was present or the subprogram is an
7412 -- intrinsic. We do this because otherwise it is an insidious error
7413 -- to call a non-pure function from pure unit and have calls
7414 -- mysteriously optimized away. What happens here is that the Import
7415 -- can bypass the normal check to ensure that pure units call only pure
7416 -- subprograms.
7418 -- The reason for the intrinsic exception is that in general, intrinsic
7419 -- functions (such as shifts) are pure anyway. The only exceptions are
7420 -- the intrinsics in GNAT.Source_Info, and that unit is not marked Pure
7421 -- in any case, so no problem arises.
7427 then
7431 -- For non-foreign convention subprograms, this is where we create
7432 -- the extra formals (for accessibility level and constrained bit
7433 -- information). We delay this till the freeze point precisely so
7434 -- that we know the convention.
7440 -- If this is convention Ada and a Valued_Procedure, that's odd
7445 and then Warn_On_Export_Import
7446 then
7447 Error_Msg_N
7452 -- Case of foreign convention
7454 else
7457 -- For foreign conventions, warn about return of unconstrained array
7462 -- If no return type, probably some other error, e.g. a
7463 -- missing full declaration, so ignore.
7468 -- If the return type is generic, we have emitted a warning
7469 -- earlier on, and there is nothing else to check here. Specific
7470 -- instantiations may lead to erroneous behavior.
7475 -- Display warning if returning unconstrained array
7480 -- Check appropriate warning is enabled (should we check for
7481 -- Warnings (Off) on specific entities here, probably so???)
7483 and then Warn_On_Export_Import
7485 -- Exclude the VM case, since return of unconstrained arrays
7486 -- is properly handled in both the JVM and .NET cases.
7489 then
7490 Error_Msg_N
7497 -- If any of the formals for an exported foreign convention
7498 -- subprogram have defaults, then emit an appropriate warning since
7499 -- this is odd (default cannot be used from non-Ada code)
7504 if Warn_On_Export_Import
7506 then
7507 Error_Msg_N
7517 -- Pragma Inline_Always is disallowed for dispatching subprograms
7518 -- because the address of such subprograms is saved in the dispatch
7519 -- table to support dispatching calls, and dispatching calls cannot
7520 -- be inlined. This is consistent with the restriction against using
7521 -- 'Access or 'Address on an Inline_Always subprogram.
7525 then
7526 Error_Msg_N
7530 -- Because of the implicit representation of inherited predefined
7531 -- operators in the front-end, the overriding status of the operation
7532 -- may be affected when a full view of a type is analyzed, and this is
7533 -- not captured by the analysis of the corresponding type declaration.
7534 -- Therefore the correctness of a not-overriding indicator must be
7535 -- rechecked when the subprogram is frozen.
7539 then
7544 ----------------------
7545 -- Is_Fully_Defined --
7546 ----------------------
7549 begin
7558 then
7559 -- Verify that the record type has no components with private types
7560 -- without completion.
7562 declare
7565 begin
7577 -- For the designated type of an access to subprogram, all types in
7578 -- the profile must be fully defined.
7581 declare
7584 begin
7597 else
7603 ---------------------------------
7604 -- Process_Default_Expressions --
7605 ---------------------------------
7607 procedure Process_Default_Expressions
7610 is
7617 begin
7620 -- A subprogram instance and its associated anonymous subprogram share
7621 -- their signature. The default expression functions are defined in the
7622 -- wrapper packages for the anonymous subprogram, and should not be
7623 -- generated again for the instance.
7628 then
7636 -- We work with a copy of the default expression because we
7637 -- do not want to disturb the original, since this would mess
7638 -- up the conformance checking.
7642 -- The analysis of the expression may generate insert actions,
7643 -- which of course must not be executed. We wrap those actions
7644 -- in a procedure that is not called, and later on eliminated.
7645 -- The following cases have no side-effects, and are analyzed
7646 -- directly.
7650 N_Integer_Literal,
7651 N_Character_Literal,
7652 N_String_Literal,
7653 N_Real_Literal)
7657 then
7658 -- If there is no default function, we must still do a full
7659 -- analyze call on the default value, to ensure that all error
7660 -- checks are performed, e.g. those associated with static
7661 -- evaluation. Note: this branch will always be taken if the
7662 -- analyzer is turned off (but we still need the error checks).
7664 -- Note: the setting of parent here is to meet the requirement
7665 -- that we can only analyze the expression while attached to
7666 -- the tree. Really the requirement is that the parent chain
7667 -- be set, we don't actually need to be in the tree.
7672 -- Default expressions are resolved with their own type if the
7673 -- context is generic, to avoid anomalies with private types.
7677 else
7681 -- If that resolved expression will raise constraint error,
7682 -- then flag the default value as raising constraint error.
7683 -- This allows a proper error message on the calls.
7689 -- If the default is a parameterless call, we use the name of
7690 -- the called function directly, and there is no body to build.
7694 then
7697 -- Else construct and analyze the body of a wrapper procedure
7698 -- that contains an object declaration to hold the expression.
7699 -- Given that this is done only to complete the analysis, it
7700 -- simpler to build a procedure than a function which might
7701 -- involve secondary stack expansion.
7703 else
7706 Dbody :=
7708 Specification =>
7715 Object_Definition =>
7719 Handled_Statement_Sequence =>
7736 ----------------------------------------
7737 -- Set_Component_Alignment_If_Not_Set --
7738 ----------------------------------------
7741 begin
7742 -- Ignore if not base type, subtypes don't need anything
7748 -- Do not override existing representation
7759 else
7760 Set_Component_Alignment
7766 --------------------------
7767 -- Set_SSO_From_Default --
7768 --------------------------
7773 begin
7774 -- Set default SSO for an array or record base type, except in case of
7775 -- a type extension (which always inherits the SSO of its parent type).
7782 then
7783 Reversed :=
7785 or else
7790 -- For a record type, if bit order is specified explicitly,
7791 -- then do not set SSO from default if not consistent. Note that
7792 -- we do not want to look at a Bit_Order attribute definition
7793 -- for a parent: if we were to inherit Bit_Order, then both
7794 -- SSO_Set_*_By_Default flags would have been cleared already
7795 -- (by Inherit_Aspects_At_Freeze_Point).
7797 and then not
7799 and then
7802 then
7803 -- If flags cause reverse storage order, then set the result. Note
7804 -- that we would have ignored the pragma setting the non default
7805 -- storage order in any case, hence the assertion at this point.
7807 pragma Assert
7812 -- For a record type, also set reversed bit order. Note: if a bit
7813 -- order has been specified explicitly, then this is a no-op.
7822 ------------------
7823 -- Undelay_Type --
7824 ------------------
7827 begin
7831 -- Since we don't want T to have a Freeze_Node, we don't want its
7832 -- Full_View or Corresponding_Record_Type to have one either.
7834 -- ??? Fundamentally, this whole handling is unpleasant. What we really
7835 -- want is to be sure that for an Itype that's part of record R and is a
7836 -- subtype of type T, that it's frozen after the later of the freeze
7837 -- points of R and T. We have no way of doing that directly, so what we
7838 -- do is force most such Itypes to be frozen as part of freezing R via
7839 -- this procedure and only delay the ones that need to be delayed
7840 -- (mostly the designated types of access types that are defined as part
7841 -- of the record).
7847 then
7855 then
7860 ------------------
7861 -- Warn_Overlay --
7862 ------------------
7864 procedure Warn_Overlay
7868 is
7870 -- The object to which the address clause applies
7876 begin
7877 -- No warning if address clause overlay warnings are off
7883 -- No warning if there is an explicit initialization
7891 -- We only give the warning for non-imported entities of a type for
7892 -- which a non-null base init proc is defined, or for objects of access
7893 -- types with implicit null initialization, or when Normalize_Scalars
7894 -- applies and the type is scalar or a string type (the latter being
7895 -- tested for because predefined String types are initialized by inline
7896 -- code rather than by an init_proc). Note that we do not give the
7897 -- warning for Initialize_Scalars, since we suppressed initialization
7898 -- in this case. Also, do not warn if Suppress_Initialization is set.
7908 then
7911 then
7916 then
7923 then
7930 -- A function call (most likely to To_Address) is probably not an
7931 -- overlay, so skip warning. Ditto if the function call was inlined
7932 -- and transformed into an entity.
7940 -- If a pragma Import follows, we assume that it is for the current
7941 -- target of the address clause, and skip the warning.
7946 then
7952 Error_Msg_N
7954 Nam);
7955 else
7956 Error_Msg_N
7958 Nam);
7961 -- Add friendly warning if initialization comes from a packed array
7962 -- component.
7965 declare
7968 begin
7973 then
7977 then
7978 Error_Msg_NE
7983 else
7990 Error_Msg_N
7993 Nam);