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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
3084 -- Check suspicious use of Import in pure unit
3088 -- Ignore internally generated entity. This happens in some cases
3089 -- of subprograms in specs, where we generate an implied body.
3093 -- Assume run-time knows what it is doing
3095 and then not GNAT_Mode
3097 -- Assume explicit Pure_Function means import is pure
3101 -- Don't need warning in relaxed semantics mode
3103 and then not Relaxed_RM_Semantics
3105 -- Assume convention Intrinsic is OK, since this is specialized.
3106 -- This deals with the DEC unit current_exception.ads
3110 -- Assume that ASM interface knows what it is doing. This deals
3111 -- with unsigned.ads in the AAMP back end.
3114 then
3115 Error_Msg_N
3117 Error_Msg_NE
3125 ------------------------
3126 -- Freeze_Record_Type --
3127 ------------------------
3139 -- Set True if the record type scope Rec has been pushed on the scope
3140 -- stack. Needed for the analysis of delayed aspects specified to the
3141 -- components of Rec.
3144 -- Scalar_Storage_Order attribute definition clause for the record
3147 -- Set True if we find at least one component with no component
3148 -- clause (used to warn about useless Pack pragmas).
3151 -- Set True if we find at least one component with a component
3152 -- clause (used to warn about useless Bit_Order pragmas, and also
3153 -- to detect cases where Implicit_Packing may have an effect).
3156 -- Set True if we find at least one component which is aliased. This
3157 -- is used to prevent Implicit_Packing of the record, since packing
3158 -- cannot modify the size of alignment of an aliased component.
3161 -- Set True if we find at least one component whose type has a
3162 -- Scalar_Storage_Order attribute definition clause.
3165 -- Set False if we encounter a component of a non-scalar type
3169 -- Accumulates total RM_Size values and total Esize values of all
3170 -- scalar components. Used for processing of Implicit_Packing.
3173 -- If N is an allocator, possibly wrapped in one or more level of
3174 -- qualified expression(s), return the inner allocator node, else
3175 -- return Empty.
3178 -- If the component subtype is an access to a constrained subtype of
3179 -- an already frozen type, make the subtype frozen as well. It might
3180 -- otherwise be frozen in the wrong scope, and a freeze node on
3181 -- subtype has no effect. Similarly, if the component subtype is a
3182 -- regular (not protected) access to subprogram, set the anonymous
3183 -- subprogram type to frozen as well, to prevent an out-of-scope
3184 -- freeze node at some eventual point of call. Protected operations
3185 -- are handled elsewhere.
3188 -- Make sure that all types mentioned in Discrete_Choices of the
3189 -- variants referenceed by the Variant_Part VP are frozen. This is
3190 -- a recursive routine to deal with nested variants.
3192 ---------------------
3193 -- Check_Allocator --
3194 ---------------------
3198 begin
3200 loop
3205 else
3211 -----------------
3212 -- Check_Itype --
3213 -----------------
3218 begin
3221 then
3224 -- In addition, add an Itype_Reference to ensure that the
3225 -- access subtype is elaborated early enough. This cannot be
3226 -- done if the subtype may depend on discriminants.
3231 then
3239 then
3244 ------------------------------------
3245 -- Freeze_Choices_In_Variant_Part --
3246 ------------------------------------
3255 begin
3256 -- Loop through variants
3261 -- Loop through choices, checking that all types are frozen
3267 then
3274 -- Check for nested variant part to process
3288 -- Start of processing for Freeze_Record_Type
3290 begin
3291 -- Deal with delayed aspect specifications for components. The
3292 -- analysis of the aspect is required to be delayed to the freeze
3293 -- point, thus we analyze the pragma or attribute definition
3294 -- clause in the tree at this point. We also analyze the aspect
3295 -- specification node at the freeze point when the aspect doesn't
3296 -- correspond to pragma/attribute definition clause.
3302 then
3307 -- The visibility to the discriminants must be restored in
3308 -- order to properly analyze the aspects.
3321 -- Pop the scope if Rec scope has been pushed on the scope stack
3322 -- during the delayed aspect analysis process.
3329 Pop_Scope;
3332 -- Freeze components and embedded subtypes
3341 -- Handle the component and discriminant case
3344 declare
3347 begin
3348 -- Freezing a record type freezes the type of each of its
3349 -- components. However, if the type of the component is
3350 -- part of this record, we do not want or need a separate
3351 -- Freeze_Node. Note that Is_Itype is wrong because that's
3352 -- also set in private type cases. We also can't check for
3353 -- the Scope being exactly Rec because of private types and
3354 -- record extensions.
3359 then
3365 -- Warn for pragma Pack overriding foreign convention
3370 -- Don't warn for aliased components, since override
3371 -- cannot happen in that case.
3374 then
3375 declare
3380 begin
3384 Error_Msg_N
3386 PP);
3388 Error_Msg_NE
3395 -- Check for error of component clause given for variable
3396 -- sized type. We have to delay this test till this point,
3397 -- since the component type has to be frozen for us to know
3398 -- if it is variable length.
3403 -- We omit this test in a generic context, it will be
3404 -- applied at instantiation time.
3409 -- Also omit this test in CodePeer mode, since we do not
3410 -- have sufficient info on size and rep clauses.
3415 -- Omit check if component has a generic type. This can
3416 -- happen in an instantiation within a generic in ASIS
3417 -- mode, where we force freeze actions without full
3418 -- expansion.
3423 -- Do the check
3425 elsif not
3426 Size_Known_At_Compile_Time
3428 then
3429 Error_Msg_N
3434 else
3438 -- Case of component requires byte alignment
3442 -- Set the enclosing record to also require byte align
3446 -- Check for component clause that is inconsistent with
3447 -- the required byte boundary alignment.
3452 then
3453 Error_Msg_N
3461 -- Gather data for possible Implicit_Packing later. Note that at
3462 -- this stage we might be dealing with a real component, or with
3463 -- an implicit subtype declaration.
3467 else
3468 Scalar_Component_Total_RM_Size :=
3470 Scalar_Component_Total_Esize :=
3474 -- If the component is an Itype with Delayed_Freeze and is either
3475 -- a record or array subtype and its base type has not yet been
3476 -- frozen, we must remove this from the entity list of this record
3477 -- and put it on the entity list of the scope of its base type.
3478 -- Note that we know that this is not the type of a component
3479 -- since we cleared Has_Delayed_Freeze for it in the previous
3480 -- loop. Thus this must be the Designated_Type of an access type,
3481 -- which is the type of a component.
3489 then
3490 declare
3494 begin
3495 -- We have a difficult case to handle here. Suppose Rec is
3496 -- subtype being defined in a subprogram that's created as
3497 -- part of the freezing of Rec'Base. In that case, we know
3498 -- that Comp'Base must have already been frozen by the time
3499 -- we get to elaborate this because Gigi doesn't elaborate
3500 -- any bodies until it has elaborated all of the declarative
3501 -- part. But Is_Frozen will not be set at this point because
3502 -- we are processing code in lexical order.
3504 -- We detect this case by going up the Scope chain of Rec
3505 -- and seeing if we have a subprogram scope before reaching
3506 -- the top of the scope chain or that of Comp'Base. If we
3507 -- do, then mark that Comp'Base will actually be frozen. If
3508 -- so, we merely undelay it.
3525 else
3528 else
3532 -- Insert in entity list of scope of base type (which
3533 -- must be an enclosing scope, because still unfrozen).
3539 -- If the component is an access type with an allocator as default
3540 -- value, the designated type will be frozen by the corresponding
3541 -- expression in init_proc. In order to place the freeze node for
3542 -- the designated type before that for the current record type,
3543 -- freeze it now.
3545 -- Same process if the component is an array of access types,
3546 -- initialized with an aggregate. If the designated type is
3547 -- private, it cannot contain allocators, and it is premature
3548 -- to freeze the type, so we check for this as well.
3553 then
3554 declare
3558 begin
3561 -- If component is pointer to a class-wide type, freeze
3562 -- the specific type in the expression being allocated.
3563 -- The expression may be a subtype indication, in which
3564 -- case freeze the subtype mark.
3566 if Is_Class_Wide_Type
3568 then
3570 Freeze_And_Append
3574 then
3575 Freeze_And_Append
3583 else
3584 Freeze_And_Append
3592 then
3595 -- Freeze the designated type when initializing a component with
3596 -- an aggregate in case the aggregate contains allocators.
3598 -- type T is ...;
3599 -- type T_Ptr is access all T;
3600 -- type T_Array is array ... of T_Ptr;
3602 -- type Rec is record
3603 -- Comp : T_Array := (others => ...);
3604 -- end record;
3608 then
3609 declare
3612 Designated_Type
3615 begin
3616 -- The only case when this sort of freezing is not done is
3617 -- when the designated type is class-wide and the root type
3618 -- is the record owning the component. This scenario results
3619 -- in a circularity because the class-wide type requires
3620 -- primitives that have not been created yet as the root
3621 -- type is in the process of being frozen.
3623 -- type Rec is tagged;
3624 -- type Rec_Ptr is access all Rec'Class;
3625 -- type Rec_Array is array ... of Rec_Ptr;
3627 -- type Rec is record
3628 -- Comp : Rec_Array := (others => ...);
3629 -- end record;
3633 then
3641 then
3651 -- Deal with default setting of reverse storage order
3655 -- Check consistent attribute setting on component types
3657 SSO_ADC := Get_Attribute_Definition_Clause
3660 declare
3662 begin
3665 Check_Component_Storage_Order
3675 -- Now deal with reverse storage order/bit order issues
3679 -- Check compatibility of Scalar_Storage_Order with Bit_Order, if
3680 -- the former is specified.
3684 -- Note: report error on Rec, not on SSO_ADC, as ADC may apply
3685 -- to some ancestor type.
3688 Error_Msg_N
3693 -- Warn if there is an Scalar_Storage_Order attribute definition
3694 -- clause but no component clause, no component that itself has
3695 -- such an attribute definition, and no pragma Pack.
3698 or else
3699 SSO_ADC_Component
3700 or else
3702 then
3703 Error_Msg_N
3705 SSO_ADC);
3709 -- Deal with Bit_Order aspect
3717 then
3718 -- Warn if clause has no effect when no component clause is
3719 -- present, but suppress warning if the Bit_Order is required
3720 -- due to the presence of a Scalar_Storage_Order attribute.
3722 Error_Msg_N
3724 Error_Msg_N
3727 -- Here is where we do the processing to adjust component clauses
3728 -- for reversed bit order, when not using reverse SSO.
3732 then
3735 -- Case where we have both an explicit Bit_Order and the same
3736 -- Scalar_Storage_Order: leave record untouched, the back-end
3737 -- will take care of required layout conversions.
3739 else
3745 -- Complete error checking on record representation clause (e.g.
3746 -- overlap of components). This is called after adjusting the
3747 -- record for reverse bit order.
3749 declare
3751 begin
3757 -- Set OK_To_Reorder_Components depending on debug flags
3761 or else
3763 then
3768 -- Check for useless pragma Pack when all components placed. We only
3769 -- do this check for record types, not subtypes, since a subtype may
3770 -- have all its components placed, and it still makes perfectly good
3771 -- sense to pack other subtypes or the parent type. We do not give
3772 -- this warning if Optimize_Alignment is set to Space, since the
3773 -- pragma Pack does have an effect in this case (it always resets
3774 -- the alignment to one).
3778 and then not Unplaced_Component
3780 then
3781 -- Reset packed status. Probably not necessary, but we do it so
3782 -- that there is no chance of the back end doing something strange
3783 -- with this redundant indication of packing.
3787 -- Give warning if redundant constructs warnings on
3790 Error_Msg_N -- CODEFIX
3796 -- If this is the record corresponding to a remote type, freeze the
3797 -- remote type here since that is what we are semantically freezing.
3798 -- This prevents the freeze node for that type in an inner scope.
3805 -- Check for controlled components and unchecked unions.
3810 -- Do not set Has_Controlled_Component on a class-wide
3811 -- equivalent type. See Make_CW_Equivalent_Type.
3814 and then
3816 or else
3819 or else
3821 and then
3823 and then
3824 Has_Controlled_Component
3826 then
3834 -- Scan component declaration for likely misuses of current
3835 -- instance, either in a constraint or a default expression.
3845 -- Enforce the restriction that access attributes with a current
3846 -- instance prefix can only apply to limited types. This comment
3847 -- is floating here, but does not seem to belong here???
3849 -- Set component alignment if not otherwise already set
3853 -- For first subtypes, check if there are any fixed-point fields with
3854 -- component clauses, where we must check the size. This is not done
3855 -- till the freeze point since for fixed-point types, we do not know
3856 -- the size until the type is frozen. Similar processing applies to
3857 -- bit packed arrays.
3865 then
3866 Check_Size
3870 Junk);
3877 -- Generate warning for applying C or C++ convention to a record
3878 -- with discriminants. This is suppressed for the unchecked union
3879 -- case, since the whole point in this case is interface C. We also
3880 -- do not generate this within instantiations, since we will have
3881 -- generated a message on the template.
3886 or else
3889 and then not In_Instance
3892 then
3893 declare
3897 begin
3902 Error_Msg_N
3904 A2);
3905 else
3906 Error_Msg_N
3908 A2);
3911 Error_Msg_NE
3917 -- See if Size is too small as is (and implicit packing might help)
3921 -- No implicit packing if even one component is explicitly placed
3923 and then not Placed_Component
3925 -- Or even one component is aliased
3927 and then not Aliased_Component
3929 -- Must have size clause and all scalar components
3932 and then All_Scalar_Components
3934 -- Do not try implicit packing on records with discriminants, too
3935 -- complicated, especially in the variant record case.
3939 -- We can implicitly pack if the specified size of the record is
3940 -- less than the sum of the object sizes (no point in packing if
3941 -- this is not the case).
3945 -- And the total RM size cannot be greater than the specified size
3946 -- since otherwise packing will not get us where we have to be.
3950 -- Never do implicit packing in CodePeer or SPARK modes since
3951 -- we don't do any packing in these modes, since this generates
3952 -- over-complex code that confuses static analysis, and in
3953 -- general, neither CodePeer not GNATprove care about the
3954 -- internal representation of objects.
3957 then
3958 -- If implicit packing enabled, do it
3963 -- Otherwise flag the size clause
3965 else
3966 declare
3968 begin
3969 Error_Msg_NE -- CODEFIX
3971 Error_Msg_N -- CODEFIX
3978 -- The following checks are only relevant when SPARK_Mode is on as
3979 -- they are not standard Ada legality rules.
3984 -- A discriminated type cannot be effectively volatile
3985 -- (SPARK RM C.6(4)).
3990 -- A tagged type cannot be effectively volatile
3991 -- (SPARK RM C.6(5)).
3997 -- A non-effectively volatile record type cannot contain
3998 -- effectively volatile components (SPARK RM C.6(2)).
4000 else
4005 then
4007 Error_Msg_N
4017 -- All done if not a full record definition
4023 -- Finally we need to check the variant part to make sure that
4024 -- all types within choices are properly frozen as part of the
4025 -- freezing of the record type.
4032 begin
4033 -- Find component list
4045 then
4050 -- Case of variant part present
4056 -- Note: we used to call Check_Choices here, but it is too early,
4057 -- since predicated subtypes are frozen here, but their freezing
4058 -- actions are in Analyze_Freeze_Entity, which has not been called
4059 -- yet for entities frozen within this procedure, so we moved that
4060 -- call to the Analyze_Freeze_Entity for the record type.
4064 -- Check that all the primitives of an interface type are abstract
4065 -- or null procedures.
4069 then
4070 declare
4074 begin
4081 -- Avoid reporting the error on inherited primitives
4084 then
4089 Error_Msg_N
4093 else
4094 Error_Msg_N
4106 -------------------------------
4107 -- Has_Boolean_Aspect_Import --
4108 -------------------------------
4115 begin
4121 -- The value of aspect Import is True when the expression is
4122 -- either missing or it is explicitly set to True.
4128 then
4139 ----------------------------
4140 -- Late_Freeze_Subprogram --
4141 ----------------------------
4148 begin
4151 else
4158 ---------------------
4159 -- Restore_Globals --
4160 ---------------------
4163 begin
4167 ------------------------------
4168 -- Wrap_Imported_Subprogram --
4169 ------------------------------
4171 -- The issue here is that our normal approach of checking preconditions
4172 -- and postconditions does not work for imported procedures, since we
4173 -- are not generating code for the body. To get around this we create
4174 -- a wrapper, as shown by the following example:
4176 -- procedure K (A : Integer);
4177 -- pragma Import (C, K);
4179 -- The spec is rewritten by removing the effects of pragma Import, but
4180 -- leaving the convention unchanged, as though the source had said:
4182 -- procedure K (A : Integer);
4183 -- pragma Convention (C, K);
4185 -- and we create a body, added to the entity K freeze actions, which
4186 -- looks like:
4188 -- procedure K (A : Integer) is
4189 -- procedure K (A : Integer);
4190 -- pragma Import (C, K);
4191 -- begin
4192 -- K (A);
4193 -- end K;
4195 -- Now the contract applies in the normal way to the outer procedure,
4196 -- and the inner procedure has no contracts, so there is no problem
4197 -- in just calling it to get the original effect.
4199 -- In the case of a function, we create an appropriate return statement
4200 -- for the subprogram body that calls the inner procedure.
4212 begin
4213 -- Nothing to do if not imported
4218 -- Test enabling conditions for wrapping
4223 and then not GNATprove_Mode
4224 then
4225 -- Here we do the wrap
4227 -- Note on calls to Copy_Separate_Tree. The trees we are copying
4228 -- here are fully analyzed, but we definitely want fully syntactic
4229 -- unanalyzed trees in the body we construct, so that the analysis
4230 -- generates the right visibility, and that is exactly what the
4231 -- calls to Copy_Separate_Tree give us.
4233 -- Acquire copy of Inline pragma, and indicate that it does not
4234 -- come from an aspect, as it applies to an internal entity.
4239 -- Fix up spec to be not imported any more
4246 -- Grab the subprogram declaration and specification
4250 -- Build parameter list that we need
4259 -- Build the call
4262 Stmt :=
4264 Expression =>
4269 else
4270 Stmt :=
4276 -- Now build the body
4278 Bod :=
4280 Specification =>
4284 Specification =>
4286 Iprag),
4287 Handled_Statement_Sequence =>
4292 -- Append the body to freeze result
4297 -- Case of imported subprogram that does not get wrapped
4299 else
4300 -- Set Is_Public. All imported entities need an external symbol
4301 -- created for them since they are always referenced from another
4302 -- object file. Note this used to be set when we set Is_Imported
4303 -- back in Sem_Prag, but now we delay it to this point, since we
4304 -- don't want to set this flag if we wrap an imported subprogram.
4310 -- Start of processing for Freeze_Entity
4312 begin
4313 -- The entity being frozen may be subject to pragma Ghost with policy
4314 -- Ignore. Set the mode now to ensure that any nodes generated during
4315 -- freezing are properly flagged as ignored Ghost.
4319 -- We are going to test for various reasons why this entity need not be
4320 -- frozen here, but in the case of an Itype that's defined within a
4321 -- record, that test actually applies to the record.
4327 then
4331 -- Do not freeze if already frozen since we only need one freeze node
4334 Restore_Globals;
4337 -- It is improper to freeze an external entity within a generic because
4338 -- its freeze node will appear in a non-valid context. The entity will
4339 -- be frozen in the proper scope after the current generic is analyzed.
4340 -- However, aspects must be analyzed because they may be queried later
4341 -- within the generic itself, and the corresponding pragma or attribute
4342 -- definition has not been analyzed yet.
4349 Restore_Globals;
4352 -- AI05-0213: A formal incomplete type does not freeze the actual. In
4353 -- the instance, the same applies to the subtype renaming the actual.
4359 then
4360 Restore_Globals;
4363 -- Formal subprograms are never frozen
4366 Restore_Globals;
4369 -- Generic types are never frozen as they lack delayed semantic checks
4372 Restore_Globals;
4375 -- Do not freeze a global entity within an inner scope created during
4376 -- expansion. A call to subprogram E within some internal procedure
4377 -- (a stream attribute for example) might require freezing E, but the
4378 -- freeze node must appear in the same declarative part as E itself.
4379 -- The two-pass elaboration mechanism in gigi guarantees that E will
4380 -- be frozen before the inner call is elaborated. We exclude constants
4381 -- from this test, because deferred constants may be frozen early, and
4382 -- must be diagnosed (e.g. in the case of a deferred constant being used
4383 -- in a default expression). If the enclosing subprogram comes from
4384 -- source, or is a generic instance, then the freeze point is the one
4385 -- mandated by the language, and we freeze the entity. A subprogram that
4386 -- is a child unit body that acts as a spec does not have a spec that
4387 -- comes from source, but can only come from source.
4392 then
4393 declare
4396 begin
4403 then
4405 else
4406 Restore_Globals;
4415 -- Similarly, an inlined instance body may make reference to global
4416 -- entities, but these references cannot be the proper freezing point
4417 -- for them, and in the absence of inlining freezing will take place in
4418 -- their own scope. Normally instance bodies are analyzed after the
4419 -- enclosing compilation, and everything has been frozen at the proper
4420 -- place, but with front-end inlining an instance body is compiled
4421 -- before the end of the enclosing scope, and as a result out-of-order
4422 -- freezing must be prevented.
4424 elsif Front_End_Inlining
4425 and then In_Instance_Body
4427 then
4428 declare
4431 begin
4436 else
4442 Restore_Globals;
4450 Restore_Globals;
4454 -- Add checks to detect proper initialization of scalars that may appear
4455 -- as subprogram parameters.
4461 -- Deal with delayed aspect specifications. The analysis of the aspect
4462 -- is required to be delayed to the freeze point, thus we analyze the
4463 -- pragma or attribute definition clause in the tree at this point. We
4464 -- also analyze the aspect specification node at the freeze point when
4465 -- the aspect doesn't correspond to pragma/attribute definition clause.
4471 -- Here to freeze the entity
4475 -- Case of entity being frozen is other than a type
4479 -- If entity is exported or imported and does not have an external
4480 -- name, now is the time to provide the appropriate default name.
4481 -- Skip this if the entity is stubbed, since we don't need a name
4482 -- for any stubbed routine. For the case on intrinsics, if no
4483 -- external name is specified, then calls will be handled in
4484 -- Exp_Intr.Expand_Intrinsic_Call, and no name is needed. If an
4485 -- external name is provided, then Expand_Intrinsic_Call leaves
4486 -- calls in place for expansion by GIGI.
4492 then
4493 Set_Encoded_Interface_Name
4496 -- If entity is an atomic object appearing in a declaration and
4497 -- the expression is an aggregate, assign it to a temporary to
4498 -- ensure that the actual assignment is done atomically rather
4499 -- than component-wise (the assignment to the temp may be done
4500 -- component-wise, but that is harmless).
4507 then
4511 -- Subprogram case
4515 -- Check for needing to wrap imported subprogram
4519 -- Freeze all parameter types and the return type (RM 13.14(14)).
4520 -- However skip this for internal subprograms. This is also where
4521 -- any extra formal parameters are created since we now know
4522 -- whether the subprogram will use a foreign convention.
4524 -- In Ada 2012, freezing a subprogram does not always freeze
4525 -- the corresponding profile (see AI05-019). An attribute
4526 -- reference is not a freezing point of the profile.
4527 -- Other constructs that should not freeze ???
4529 -- This processing doesn't apply to internal entities (see below)
4533 Restore_Globals;
4538 -- Must freeze its parent first if it is a derived subprogram
4544 -- We don't freeze internal subprograms, because we don't normally
4545 -- want addition of extra formals or mechanism setting to happen
4546 -- for those. However we do pass through predefined dispatching
4547 -- cases, since extra formals may be needed in some cases, such as
4548 -- for the stream 'Input function (build-in-place formals).
4552 then
4558 Restore_Globals;
4562 -- If warning on suspicious contracts then check for the case of
4563 -- a postcondition other than False for a No_Return subprogram.
4566 and then Warn_On_Suspicious_Contract
4568 then
4569 declare
4573 begin
4576 Name_Postcondition,
4577 Name_Refined_Post)
4578 then
4579 Exp :=
4580 Expression
4585 then
4586 Error_Msg_NE
4597 -- Here for other than a subprogram or type
4599 else
4600 -- If entity has a type, and it is not a generic unit, then
4601 -- freeze it first (RM 13.14(10)).
4605 then
4608 -- For an object of an anonymous array type, aspects on the
4609 -- object declaration apply to the type itself. This is the
4610 -- case for Atomic_Components, Volatile_Components, and
4611 -- Independent_Components. In these cases analysis of the
4612 -- generated pragma will mark the anonymous types accordingly,
4613 -- and the object itself does not require a freeze node.
4619 then
4626 -- Special processing for objects created by object declaration
4630 -- Abstract type allowed only for C++ imported variables or
4631 -- constants.
4633 -- Note: we inhibit this check for objects that do not come
4634 -- from source because there is at least one case (the
4635 -- expansion of x'Class'Input where x is abstract) where we
4636 -- legitimately generate an abstract object.
4642 then
4647 Error_Msg_NE
4652 Error_Msg_N -- CODEFIX
4658 -- For object created by object declaration, perform required
4659 -- categorization (preelaborate and pure) checks. Defer these
4660 -- checks to freeze time since pragma Import inhibits default
4661 -- initialization and thus pragma Import affects these checks.
4665 -- If there is an address clause, check that it is valid
4669 -- Reset Is_True_Constant for non-constant aliased object. We
4670 -- consider that the fact that a non-constant object is aliased
4671 -- may indicate that some funny business is going on, e.g. an
4672 -- aliased object is passed by reference to a procedure which
4673 -- captures the address of the object, which is later used to
4674 -- assign a new value, even though the compiler thinks that
4675 -- it is not modified. Such code is highly dubious, but we
4676 -- choose to make it "work" for non-constant aliased objects.
4677 -- Note that we used to do this for all aliased objects,
4678 -- whether or not constant, but this caused anomalies down
4679 -- the line because we ended up with static objects that
4680 -- were not Is_True_Constant. Not resetting Is_True_Constant
4681 -- for (aliased) constant objects ensures that this anomaly
4682 -- never occurs.
4684 -- However, we don't do that for internal entities. We figure
4685 -- that if we deliberately set Is_True_Constant for an internal
4686 -- entity, e.g. a dispatch table entry, then we mean it.
4691 then
4695 -- If the object needs any kind of default initialization, an
4696 -- error must be issued if No_Default_Initialization applies.
4697 -- The check doesn't apply to imported objects, which are not
4698 -- ever default initialized, and is why the check is deferred
4699 -- until freezing, at which point we know if Import applies.
4700 -- Deferred constants are also exempted from this test because
4701 -- their completion is explicit, or through an import pragma.
4705 then
4711 and then
4716 or else
4719 then
4721 Check_Restriction
4725 -- Check that a Thread_Local_Storage variable does not have
4726 -- default initialization, and any explicit initialization must
4727 -- either be the null constant or a static constant.
4730 declare
4732 begin
4733 if Has_Default_Initialization
4734 or else
4736 and then
4738 or else not
4740 or else
4742 then
4743 Error_Msg_NE
4746 Error_Msg_NE
4753 -- For imported objects, set Is_Public unless there is also an
4754 -- address clause, which means that there is no external symbol
4755 -- needed for the Import (Is_Public may still be set for other
4756 -- unrelated reasons). Note that we delayed this processing
4757 -- till freeze time so that we can be sure not to set the flag
4758 -- if there is an address clause. If there is such a clause,
4759 -- then the only purpose of the Import pragma is to suppress
4760 -- implicit initialization.
4766 -- For source objects that are not Imported and are library
4767 -- level, if no linker section pragma was given inherit the
4768 -- appropriate linker section from the corresponding type.
4774 then
4775 Set_Linker_Section_Pragma
4779 -- For convention C objects of an enumeration type, warn if
4780 -- the size is not integer size and no explicit size given.
4781 -- Skip warning for Boolean, and Character, assume programmer
4782 -- expects 8-bit sizes for these cases.
4785 or else
4792 then
4794 Error_Msg_N
4796 E);
4801 -- Check that a constant which has a pragma Volatile[_Components]
4802 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
4804 -- Note: Atomic[_Components] also sets Volatile[_Components]
4810 then
4811 -- Make sure we actually have a pragma, and have not merely
4812 -- inherited the indication from elsewhere (e.g. an address
4813 -- clause, which is not good enough in RM terms).
4816 or else
4818 then
4819 Error_Msg_N
4824 or else
4826 then
4827 Error_Msg_N
4833 -- Static objects require special handling
4837 then
4841 -- Remaining step is to layout objects
4845 then
4849 -- For an object that does not have delayed freezing, and whose
4850 -- initialization actions have been captured in a compound
4851 -- statement, move them back now directly within the enclosing
4852 -- statement sequence.
4856 then
4861 -- Case of a type or subtype being frozen
4863 else
4864 -- We used to check here that a full type must have preelaborable
4865 -- initialization if it completes a private type specified with
4866 -- pragma Preelaborable_Initialization, but that missed cases where
4867 -- the types occur within a generic package, since the freezing
4868 -- that occurs within a containing scope generally skips traversal
4869 -- of a generic unit's declarations (those will be frozen within
4870 -- instances). This check was moved to Analyze_Package_Specification.
4872 -- The type may be defined in a generic unit. This can occur when
4873 -- freezing a generic function that returns the type (which is
4874 -- defined in a parent unit). It is clearly meaningless to freeze
4875 -- this type. However, if it is a subtype, its size may be determi-
4876 -- nable and used in subsequent checks, so might as well try to
4877 -- compute it.
4879 -- In Ada 2012, Freeze_Entities is also used in the front end to
4880 -- trigger the analysis of aspect expressions, so in this case we
4881 -- want to continue the freezing process.
4885 and then
4888 then
4890 Restore_Globals;
4894 -- Check for error of Type_Invariant'Class applied to an untagged
4895 -- type (check delayed to freeze time when full type is available).
4897 declare
4899 begin
4903 then
4904 Error_Msg_NE
4907 Error_Msg_N
4912 -- A Ghost type cannot be effectively volatile (SPARK RM 6.9(8))
4916 then
4920 -- Deal with special cases of freezing for subtype
4924 -- Before we do anything else, a specialized test for the case of
4925 -- a size given for an array where the array needs to be packed,
4926 -- but was not so the size cannot be honored. This is the case
4927 -- where implicit packing may apply. The reason we do this so
4928 -- early is that if we have implicit packing, the layout of the
4929 -- base type is affected, so we must do this before we freeze
4930 -- the base type.
4932 -- We could do this processing only if implicit packing is enabled
4933 -- since in all other cases, the error would be caught by the back
4934 -- end. However, we choose to do the check even if we do not have
4935 -- implicit packing enabled, since this allows us to give a more
4936 -- useful error message (advising use of pragmas Implicit_Packing
4937 -- or Pack).
4940 declare
4951 -- Number of elements in array
4953 begin
4954 -- Check enabling conditions. These are straightforward
4955 -- except for the test for a limited composite type. This
4956 -- eliminates the rare case of a array of limited components
4957 -- where there are issues of whether or not we can go ahead
4958 -- and pack the array (since we can't freely pack and unpack
4959 -- arrays if they are limited).
4961 -- Note that we check the root type explicitly because the
4962 -- whole point is we are doing this test before we have had
4963 -- a chance to freeze the base type (and it is that freeze
4964 -- action that causes stuff to be inherited).
4977 then
4978 -- Compute number of elements in array
4986 and then
4988 then
4992 Num_Elmts :=
4993 Num_Elmts *
4999 -- What we are looking for here is the situation where
5000 -- the RM_Size given would be exactly right if there was
5001 -- a pragma Pack (resulting in the component size being
5002 -- the same as the RM_Size). Furthermore, the component
5003 -- type size must be an odd size (not a multiple of
5004 -- storage unit). If the component RM size is an exact
5005 -- number of storage units that is a power of two, the
5006 -- array is not packed and has a standard representation.
5010 then
5011 -- For implicit packing mode, just set the component
5012 -- size silently.
5020 -- Otherwise give an error message
5022 else
5023 Error_Msg_NE
5025 Error_Msg_N -- CODEFIX
5031 and then Implicit_Packing
5032 and then
5034 or else
5036 or else
5038 then
5039 -- Not a packed array, but indicate the desired
5040 -- component size, for the back-end.
5050 -- If ancestor subtype present, freeze that first. Note that this
5051 -- will also get the base type frozen. Need RM reference ???
5058 -- No ancestor subtype present
5060 else
5061 -- See if we have a nearest ancestor that has a predicate.
5062 -- That catches the case of derived type with a predicate.
5063 -- Need RM reference here ???
5071 -- Freeze base type before freezing the entity (RM 13.14(15))
5078 -- A subtype inherits all the type-related representation aspects
5079 -- from its parents (RM 13.1(8)).
5083 -- For a derived type, freeze its parent type first (RM 13.14(15))
5089 -- A derived type inherits each type-related representation aspect
5090 -- of its parent type that was directly specified before the
5091 -- declaration of the derived type (RM 13.1(15)).
5096 -- Check for incompatible size and alignment for record type
5098 if Warn_On_Size_Alignment
5102 -- If explicit Object_Size clause given assume that the programmer
5103 -- knows what he is doing, and expects the compiler behavior.
5107 -- Check for size not a multiple of alignment
5110 then
5111 declare
5117 begin
5120 -- Give a warning
5124 Error_Msg_NE
5130 else
5132 Error_Msg_NE
5145 -- Array type
5150 -- For a class-wide type, the corresponding specific type is
5151 -- frozen as well (RM 13.14(15))
5156 -- If the base type of the class-wide type is still incomplete,
5157 -- the class-wide remains unfrozen as well. This is legal when
5158 -- E is the formal of a primitive operation of some other type
5159 -- which is being frozen.
5163 Restore_Globals;
5167 -- The equivalent type associated with a class-wide subtype needs
5168 -- to be frozen to ensure that its layout is done.
5172 then
5176 -- Generate an itype reference for a library-level class-wide type
5177 -- at the freeze point. Otherwise the first explicit reference to
5178 -- the type may appear in an inner scope which will be rejected by
5179 -- the back-end.
5183 then
5184 declare
5187 begin
5190 -- From a gigi point of view, a class-wide subtype derives
5191 -- from its record equivalent type. As a result, the itype
5192 -- reference must appear after the freeze node of the
5193 -- equivalent type or gigi will reject the reference.
5197 then
5199 else
5205 -- For a record type or record subtype, freeze all component types
5206 -- (RM 13.14(15)). We test for E_Record_(sub)Type here, rather than
5207 -- using Is_Record_Type, because we don't want to attempt the freeze
5208 -- for the case of a private type with record extension (we will do
5209 -- that later when the full type is frozen).
5214 then
5217 -- For a concurrent type, freeze corresponding record type. This does
5218 -- not correspond to any specific rule in the RM, but the record type
5219 -- is essentially part of the concurrent type. Also freeze all local
5220 -- entities. This includes record types created for entry parameter
5221 -- blocks and whatever local entities may appear in the private part.
5235 -- The guard on the presence of the Etype seems to be needed
5236 -- for some CodePeer (-gnatcC) cases, but not clear why???
5241 then
5252 -- Private types are required to point to the same freeze node as
5253 -- their corresponding full views. The freeze node itself has to
5254 -- point to the partial view of the entity (because from the partial
5255 -- view, we can retrieve the full view, but not the reverse).
5256 -- However, in order to freeze correctly, we need to freeze the full
5257 -- view. If we are freezing at the end of a scope (or within the
5258 -- scope) of the private type, the partial and full views will have
5259 -- been swapped, the full view appears first in the entity chain and
5260 -- the swapping mechanism ensures that the pointers are properly set
5261 -- (on scope exit).
5263 -- If we encounter the partial view before the full view (e.g. when
5264 -- freezing from another scope), we freeze the full view, and then
5265 -- set the pointers appropriately since we cannot rely on swapping to
5266 -- fix things up (subtypes in an outer scope might not get swapped).
5268 -- If the full view is itself private, the above requirements apply
5269 -- to the underlying full view instead of the full view. But there is
5270 -- no swapping mechanism for the underlying full view so we need to
5271 -- set the pointers appropriately in both cases.
5275 then
5276 -- The construction of the dispatch table associated with library
5277 -- level tagged types forces freezing of all the primitives of the
5278 -- type, which may cause premature freezing of the partial view.
5279 -- For example:
5281 -- package Pkg is
5282 -- type T is tagged private;
5283 -- type DT is new T with private;
5284 -- procedure Prim (X : in out T; Y : in out DT'Class);
5285 -- private
5286 -- type T is tagged null record;
5287 -- Obj : T;
5288 -- type DT is new T with null record;
5289 -- end;
5291 -- In this case the type will be frozen later by the usual
5292 -- mechanism: an object declaration, an instantiation, or the
5293 -- end of a declarative part.
5297 then
5299 Restore_Globals;
5302 -- Case of full view present
5306 -- If full view has already been frozen, then no further
5307 -- processing is required
5313 -- Otherwise freeze full view and patch the pointers so that
5314 -- the freeze node will elaborate both views in the back end.
5315 -- However, if full view is itself private, freeze underlying
5316 -- full view instead and patch the pointers so that the freeze
5317 -- node will elaborate the three views in the back end.
5319 else
5320 declare
5323 begin
5326 then
5334 then
5341 else
5354 else
5355 -- {Incomplete,Private}_Subtypes with Full_Views
5356 -- constrained by discriminants.
5367 -- AI-117 requires that the convention of a partial view be the
5368 -- same as the convention of the full view. Note that this is a
5369 -- recognized breach of privacy, but it's essential for logical
5370 -- consistency of representation, and the lack of a rule in
5371 -- RM95 was an oversight.
5378 -- Size information is copied from the full view to the
5379 -- incomplete or private view for consistency.
5381 -- We skip this is the full view is not a type. This is very
5382 -- strange of course, and can only happen as a result of
5383 -- certain illegalities, such as a premature attempt to derive
5384 -- from an incomplete type.
5391 Restore_Globals;
5394 -- Case of underlying full view present
5398 then
5403 -- Patch the pointers so that the freeze node will elaborate
5404 -- both views in the back end.
5413 else
5421 Restore_Globals;
5424 -- Case of no full view present. If entity is derived or subtype,
5425 -- it is safe to freeze, correctness depends on the frozen status
5426 -- of parent. Otherwise it is either premature usage, or a Taft
5427 -- amendment type, so diagnosis is at the point of use and the
5428 -- type might be frozen later.
5433 else
5435 Restore_Globals;
5439 -- For access subprogram, freeze types of all formals, the return
5440 -- type was already frozen, since it is the Etype of the function.
5441 -- Formal types can be tagged Taft amendment types, but otherwise
5442 -- they cannot be incomplete.
5450 then
5454 -- AI05-151: Incomplete types are allowed in access to
5455 -- subprogram specifications.
5458 Error_Msg_NE
5469 -- For access to a protected subprogram, freeze the equivalent type
5470 -- (however this is not set if we are not generating code or if this
5471 -- is an anonymous type used just for resolution).
5479 -- Generic types are never seen by the back-end, and are also not
5480 -- processed by the expander (since the expander is turned off for
5481 -- generic processing), so we never need freeze nodes for them.
5484 Restore_Globals;
5488 -- Some special processing for non-generic types to complete
5489 -- representation details not known till the freeze point.
5494 -- Some error checks required for ordinary fixed-point type. Defer
5495 -- these till the freeze-point since we need the small and range
5496 -- values. We only do these checks for base types
5501 Error_Msg_N
5506 Error_Msg_N
5512 Error_Msg_N
5518 Error_Msg_N
5530 and then Warn_On_Suspicious_Modulus_Value
5531 then
5535 -- The pool applies to named and anonymous access types, but not
5536 -- to subprogram and to internal types generated for 'Access
5537 -- references.
5542 then
5543 -- If a pragma Default_Storage_Pool applies, and this type has no
5544 -- Storage_Pool or Storage_Size clause (which must have occurred
5545 -- before the freezing point), then use the default. This applies
5546 -- only to base types.
5548 -- None of this applies to access to subprograms, for which there
5549 -- are clearly no pools.
5555 then
5556 -- Case of pragma Default_Storage_Pool (null)
5561 -- Case of pragma Default_Storage_Pool (storage_pool_NAME)
5563 else
5568 -- Check restriction for standard storage pool
5574 -- Deal with error message for pure access type. This is not an
5575 -- error in Ada 2005 if there is no pool (see AI-366).
5581 then
5585 Error_Msg_N
5589 Error_Msg_N
5592 else
5593 Error_Msg_N
5600 -- Case of composite types
5604 -- AI-117 requires that all new primitives of a tagged type must
5605 -- inherit the convention of the full view of the type. Inherited
5606 -- and overriding operations are defined to inherit the convention
5607 -- of their parent or overridden subprogram (also specified in
5608 -- AI-117), which will have occurred earlier (in Derive_Subprogram
5609 -- and New_Overloaded_Entity). Here we set the convention of
5610 -- primitives that are still convention Ada, which will ensure
5611 -- that any new primitives inherit the type's convention. Class-
5612 -- wide types can have a foreign convention inherited from their
5613 -- specific type, but are excluded from this since they don't have
5614 -- any associated primitives.
5619 then
5620 declare
5624 begin
5636 -- If the type is a simple storage pool type, then this is where
5637 -- we attempt to locate and validate its Allocate, Deallocate, and
5638 -- Storage_Size operations (the first is required, and the latter
5639 -- two are optional). We also verify that the full type for a
5640 -- private type is allowed to be a simple storage pool type.
5644 then
5645 -- If the type is marked Has_Private_Declaration, then this is
5646 -- a full type for a private type that was specified with the
5647 -- pragma Simple_Storage_Pool_Type, and here we ensure that the
5648 -- pragma is allowed for the full type (for example, it can't
5649 -- be an array type, or a nonlimited record type).
5654 then
5656 Error_Msg_N
5667 procedure Validate_Simple_Pool_Op_Formal
5674 -- Validate one formal Pool_Op_Formal of the candidate pool
5675 -- operation Pool_Op. The formal must be of Expected_Type
5676 -- and have mode Expected_Mode. OK_Formal will be set to
5677 -- False if the formal doesn't match. If OK_Formal is False
5678 -- on entry, then the formal will effectively be ignored
5679 -- (because validation of the pool op has already failed).
5680 -- Upon return, Pool_Op_Formal will be updated to the next
5681 -- formal, if any.
5683 procedure Validate_Simple_Pool_Operation
5685 -- Search for and validate a simple pool operation with the
5686 -- name Op_Name. If the name is Allocate, then there must be
5687 -- exactly one such primitive operation for the simple pool
5688 -- type. If the name is Deallocate or Storage_Size, then
5689 -- there can be at most one such primitive operation. The
5690 -- profile of the located primitive must conform to what
5691 -- is expected for each operation.
5693 ------------------------------------
5694 -- Validate_Simple_Pool_Op_Formal --
5695 ------------------------------------
5697 procedure Validate_Simple_Pool_Op_Formal
5704 is
5705 begin
5706 -- If OK_Formal is False on entry, then simply ignore
5707 -- the formal, because an earlier formal has already
5708 -- been flagged.
5713 -- If no formal is passed in, then issue an error for a
5714 -- missing formal.
5717 Error_Msg_NE
5727 -- If the pool type was expected for this formal, then
5728 -- this will not be considered a candidate operation
5729 -- for the simple pool, so we unset OK_Formal so that
5730 -- the op and any later formals will be ignored.
5737 else
5738 Error_Msg_NE
5745 -- Issue error if formal's mode is not the expected one
5748 Error_Msg_N
5750 Pool_Op_Formal);
5753 -- Advance to the next formal
5758 ------------------------------------
5759 -- Validate_Simple_Pool_Operation --
5760 ------------------------------------
5762 procedure Validate_Simple_Pool_Operation
5764 is
5770 begin
5771 pragma Assert
5773 Name_Deallocate,
5774 Name_Storage_Size));
5778 -- For each homonym declared immediately in the scope
5779 -- of the simple storage pool type, determine whether
5780 -- the homonym is an operation of the pool type, and,
5781 -- if so, check that its profile is as expected for
5782 -- a simple pool operation of that name.
5788 then
5793 -- The first parameter must be of the pool type
5794 -- in order for the operation to qualify.
5797 Validate_Simple_Pool_Op_Formal
5800 else
5801 Validate_Simple_Pool_Op_Formal
5806 -- If another operation with this name has already
5807 -- been located for the type, then flag an error,
5808 -- since we only allow the type to have a single
5809 -- such primitive.
5812 Error_Msg_NE
5817 -- In the case of Allocate and Deallocate, a formal
5818 -- of type System.Address is required.
5821 Validate_Simple_Pool_Op_Formal
5826 Validate_Simple_Pool_Op_Formal
5831 -- In the case of Allocate and Deallocate, formals
5832 -- of type Storage_Count are required as the third
5833 -- and fourth parameters.
5836 Validate_Simple_Pool_Op_Formal
5839 Validate_Simple_Pool_Op_Formal
5844 -- If no mismatched formals have been found (Is_OK)
5845 -- and no excess formals are present, then this
5846 -- operation has been validated, so record it.
5856 -- There must be a valid Allocate operation for the type,
5857 -- so issue an error if none was found.
5861 then
5867 -- Simple pool operations can't be abstract
5870 Error_Msg_N
5875 -- The Storage_Size operation must be a function with
5876 -- Storage_Count as its result type.
5880 Error_Msg_N
5884 Error_Msg_NE
5889 -- Allocate and Deallocate must be procedures
5892 Error_Msg_N
5898 -- Start of processing for Validate_Simple_Pool_Ops
5900 begin
5908 -- Now that all types from which E may depend are frozen, see if the
5909 -- size is known at compile time, if it must be unsigned, or if
5910 -- strict alignment is required
5919 -- Do not allow a size clause for a type which does not have a size
5920 -- that is known at compile time
5924 then
5925 -- Suppress this message if errors posted on E, even if we are
5926 -- in all errors mode, since this is often a junk message
5929 Error_Msg_N
5935 -- Now we set/verify the representation information, in particular
5936 -- the size and alignment values. This processing is not required for
5937 -- generic types, since generic types do not play any part in code
5938 -- generation, and so the size and alignment values for such types
5939 -- are irrelevant. Ditto for types declared within a generic unit,
5940 -- which may have components that depend on generic parameters, and
5941 -- that will be recreated in an instance.
5946 -- Otherwise we call the layout procedure
5948 else
5952 -- If this is an access to subprogram whose designated type is itself
5953 -- a subprogram type, the return type of this anonymous subprogram
5954 -- type must be decorated as well.
5958 then
5962 -- If the type has a Defaut_Value/Default_Component_Value aspect,
5963 -- this is where we analye the expression (after the type is frozen,
5964 -- since in the case of Default_Value, we are analyzing with the
5965 -- type itself, and we treat Default_Component_Value similarly for
5966 -- the sake of uniformity).
5969 declare
5974 begin
5979 else
5990 Flag_Non_Static_Expr
5997 -- End of freeze processing for type entities
6000 -- Here is where we logically freeze the current entity. If it has a
6001 -- freeze node, then this is the point at which the freeze node is
6002 -- linked into the result list.
6006 -- If a freeze node is already allocated, use it, otherwise allocate
6007 -- a new one. The preallocation happens in the case of anonymous base
6008 -- types, where we preallocate so that we can set First_Subtype_Link.
6009 -- Note that we reset the Sloc to the current freeze location.
6015 else
6026 -- A final pass over record types with discriminants. If the type
6027 -- has an incomplete declaration, there may be constrained access
6028 -- subtypes declared elsewhere, which do not depend on the discrimi-
6029 -- nants of the type, and which are used as component types (i.e.
6030 -- the full view is a recursive type). The designated types of these
6031 -- subtypes can only be elaborated after the type itself, and they
6032 -- need an itype reference.
6036 then
6037 declare
6042 begin
6052 then
6064 -- When a type is frozen, the first subtype of the type is frozen as
6065 -- well (RM 13.14(15)). This has to be done after freezing the type,
6066 -- since obviously the first subtype depends on its own base type.
6071 -- If we just froze a tagged non-class wide record, then freeze the
6072 -- corresponding class-wide type. This must be done after the tagged
6073 -- type itself is frozen, because the class-wide type refers to the
6074 -- tagged type which generates the class.
6079 then
6086 -- Special handling for subprograms
6090 -- If subprogram has address clause then reset Is_Public flag, since
6091 -- we do not want the backend to generate external references.
6095 then
6100 Restore_Globals;
6104 -----------------------------
6105 -- Freeze_Enumeration_Type --
6106 -----------------------------
6109 begin
6110 -- By default, if no size clause is present, an enumeration type with
6111 -- Convention C is assumed to interface to a C enum, and has integer
6112 -- size. This applies to types. For subtypes, verify that its base
6113 -- type has no size clause either. Treat other foreign conventions
6114 -- in the same way, and also make sure alignment is set right.
6121 -- Don't do this if Short_Enums on target
6123 and then not Target_Short_Enums
6124 then
6128 -- Normal Ada case or size clause present or not Long_C_Enums on target
6130 else
6131 -- If the enumeration type interfaces to C, and it has a size clause
6132 -- that specifies less than int size, it warrants a warning. The
6133 -- user may intend the C type to be an enum or a char, so this is
6134 -- not by itself an error that the Ada compiler can detect, but it
6135 -- it is a worth a heads-up. For Boolean and Character types we
6136 -- assume that the programmer has the proper C type in mind.
6144 -- Don't do this if Short_Enums on target
6146 and then not Target_Short_Enums
6147 then
6148 Error_Msg_N
6156 -----------------------
6157 -- Freeze_Expression --
6158 -----------------------
6169 -- This flag is set true if the entity must be frozen outside the
6170 -- current subprogram. This happens in the case of expander generated
6171 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
6172 -- not freeze all entities like other bodies, but which nevertheless
6173 -- may reference entities that have to be frozen before the body and
6174 -- obviously cannot be frozen inside the body.
6177 -- If the expression is an array aggregate, the type of the component
6178 -- expressions is also frozen. If the component type is an access type
6179 -- and the expressions include allocators, the designed type is frozen
6180 -- as well.
6183 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
6184 -- it is the handled statement sequence of an expander-generated
6185 -- subprogram (init proc, stream subprogram, or renaming as body).
6186 -- If so, this is not a freezing context.
6188 -----------------------------------------
6189 -- Find_Aggregate_Component_Desig_Type --
6190 -----------------------------------------
6196 begin
6222 ----------------------
6223 -- In_Expanded_Body --
6224 ----------------------
6230 begin
6233 else
6240 else
6243 -- The following are expander-created bodies, or bodies that
6244 -- are not freeze points.
6253 N_Subprogram_Renaming_Declaration,
6254 N_Expression_Function))
6255 then
6257 else
6263 -- Start of processing for Freeze_Expression
6265 begin
6266 -- Immediate return if freezing is inhibited. This flag is set by the
6267 -- analyzer to stop freezing on generated expressions that would cause
6268 -- freezing if they were in the source program, but which are not
6269 -- supposed to freeze, since they are created.
6275 -- If expression is non-static, then it does not freeze in a default
6276 -- expression, see section "Handling of Default Expressions" in the
6277 -- spec of package Sem for further details. Note that we have to make
6278 -- sure that we actually have a real expression (if we have a subtype
6279 -- indication, we can't test Is_OK_Static_Expression). However, we
6280 -- exclude the case of the prefix of an attribute of a static scalar
6281 -- subtype from this early return, because static subtype attributes
6282 -- should always cause freezing, even in default expressions, but
6283 -- the attribute may not have been marked as static yet (because in
6284 -- Resolve_Attribute, the call to Eval_Attribute follows the call of
6285 -- Freeze_Expression on the prefix).
6287 if In_Spec_Exp
6294 then
6298 -- Freeze type of expression if not frozen already
6306 -- Base type may be an derived numeric type that is frozen at
6307 -- the point of declaration, but first_subtype is still unfrozen.
6314 -- For entity name, freeze entity if not frozen already. A special
6315 -- exception occurs for an identifier that did not come from source.
6316 -- We don't let such identifiers freeze a non-internal entity, i.e.
6317 -- an entity that did come from source, since such an identifier was
6318 -- generated by the expander, and cannot have any semantic effect on
6319 -- the freezing semantics. For example, this stops the parameter of
6320 -- an initialization procedure from freezing the variable.
6327 then
6334 else
6338 -- For an allocator freeze designated type if not frozen already
6340 -- For an aggregate whose component type is an access type, freeze the
6341 -- designated type now, so that its freeze does not appear within the
6342 -- loop that might be created in the expansion of the aggregate. If the
6343 -- designated type is a private type without full view, the expression
6344 -- cannot contain an allocator, so the type is not frozen.
6346 -- For a function, we freeze the entity when the subprogram declaration
6347 -- is frozen, but a function call may appear in an initialization proc.
6348 -- before the declaration is frozen. We need to generate the extra
6349 -- formals, if any, to ensure that the expansion of the call includes
6350 -- the proper actuals. This only applies to Ada subprograms, not to
6351 -- imported ones.
6362 then
6364 -- Check whether aggregate includes allocators.
6369 when N_Selected_Component |
6370 N_Indexed_Component |
6371 N_Slice =>
6382 then
6393 then
6397 -- All done if nothing needs freezing
6402 then
6406 -- Examine the enclosing context by climbing the parent chain. The
6407 -- traversal serves two purposes - to detect scenarios where freezeing
6408 -- is not needed and to find the proper insertion point for the freeze
6409 -- nodes. Although somewhat similar to Insert_Actions, this traversal
6410 -- is freezing semantics-sensitive. Inserting freeze nodes blindly in
6411 -- the tree may result in types being frozen too early.
6414 loop
6417 -- If we don't have a parent, then we are not in a well-formed tree.
6418 -- This is an unusual case, but there are some legitimate situations
6419 -- in which this occurs, notably when the expressions in the range of
6420 -- a type declaration are resolved. We simply ignore the freeze
6421 -- request in this case. Is this right ???
6427 -- See if we have got to an appropriate point in the tree
6431 -- A special test for the exception of (RM 13.14(8)) for the case
6432 -- of per-object expressions (RM 3.8(18)) occurring in component
6433 -- definition or a discrete subtype definition. Note that we test
6434 -- for a component declaration which includes both cases we are
6435 -- interested in, and furthermore the tree does not have explicit
6436 -- nodes for either of these two constructs.
6440 -- The case we want to test for here is an identifier that is
6441 -- a per-object expression, this is either a discriminant that
6442 -- appears in a context other than the component declaration
6443 -- or it is a reference to the type of the enclosing construct.
6445 -- For either of these cases, we skip the freezing
6447 if not In_Spec_Expression
6450 then
6451 -- We recognize the discriminant case by just looking for
6452 -- a reference to a discriminant. It can only be one for
6453 -- the enclosing construct. Skip freezing in this case.
6458 -- For the case of a reference to the enclosing record,
6459 -- (or task or protected type), we look for a type that
6460 -- matches the current scope.
6467 -- If we have an enumeration literal that appears as the choice in
6468 -- the aggregate of an enumeration representation clause, then
6469 -- freezing does not occur (RM 13.14(10)).
6473 -- The case we are looking for is an enumeration literal
6477 then
6478 -- If enumeration literal appears directly as the choice,
6479 -- do not freeze (this is the normal non-overloaded case)
6483 then
6486 -- If enumeration literal appears as the name of function
6487 -- which is the choice, then also do not freeze. This
6488 -- happens in the overloaded literal case, where the
6489 -- enumeration literal is temporarily changed to a function
6490 -- call for overloading analysis purposes.
6493 and then
6495 and then
6497 then
6502 -- Normally if the parent is a handled sequence of statements,
6503 -- then the current node must be a statement, and that is an
6504 -- appropriate place to insert a freeze node.
6508 -- An exception occurs when the sequence of statements is for
6509 -- an expander generated body that did not do the usual freeze
6510 -- all operation. In this case we usually want to freeze
6511 -- outside this body, not inside it, and we skip past the
6512 -- subprogram body that we are inside.
6515 declare
6519 begin
6520 -- Freeze the entity only when it is declared inside the
6521 -- body of the expander generated procedure. This case
6522 -- is recognized by the scope of the entity or its type,
6523 -- which is either the spec for some enclosing body, or
6524 -- (in the case of init_procs, for which there are no
6525 -- separate specs) the current scope.
6531 or else
6533 then
6539 then
6544 -- An expression function may act as a completion of
6545 -- a function declaration. As such, it can reference
6546 -- entities declared between the two views:
6548 -- Hidden []; -- 1
6549 -- function F return ...;
6550 -- private
6551 -- function Hidden return ...;
6552 -- function F return ... is (Hidden); -- 2
6554 -- Refering to the example above, freezing the expression
6555 -- of F (2) would place Hidden's freeze node (1) in the
6556 -- wrong place. Avoid explicit freezing and let the usual
6557 -- scenarios do the job - for example, reaching the end
6558 -- of the private declarations, or a call to F.
6561 N_Expression_Function
6562 then
6565 -- Freeze outside the body
6567 else
6573 -- Here if normal case where we are in handled statement
6574 -- sequence and want to do the insertion right there.
6576 else
6580 -- If parent is a body or a spec or a block, then the current node
6581 -- is a statement or declaration and we can insert the freeze node
6582 -- before it.
6584 when N_Block_Statement |
6585 N_Entry_Body |
6586 N_Package_Body |
6587 N_Package_Specification |
6588 N_Protected_Body |
6589 N_Subprogram_Body |
6592 -- The expander is allowed to define types in any statements list,
6593 -- so any of the following parent nodes also mark a freezing point
6594 -- if the actual node is in a list of statements or declarations.
6596 when N_Abortable_Part |
6597 N_Accept_Alternative |
6598 N_And_Then |
6599 N_Case_Statement_Alternative |
6600 N_Compilation_Unit_Aux |
6601 N_Conditional_Entry_Call |
6602 N_Delay_Alternative |
6603 N_Elsif_Part |
6604 N_Entry_Call_Alternative |
6605 N_Exception_Handler |
6606 N_Extended_Return_Statement |
6607 N_Freeze_Entity |
6608 N_If_Statement |
6609 N_Or_Else |
6610 N_Selective_Accept |
6611 N_Triggering_Alternative =>
6615 -- Freeze nodes produced by an expression coming from the Actions
6616 -- list of a N_Expression_With_Actions node must remain within the
6617 -- Actions list. Inserting the freeze nodes further up the tree
6618 -- may lead to use before declaration issues in the case of array
6619 -- types.
6624 then
6628 -- Note: N_Loop_Statement is a special case. A type that appears
6629 -- in the source can never be frozen in a loop (this occurs only
6630 -- because of a loop expanded by the expander), so we keep on
6631 -- going. Otherwise we terminate the search. Same is true of any
6632 -- entity which comes from source. (if they have predefined type,
6633 -- that type does not appear to come from source, but the entity
6634 -- should not be frozen here).
6640 -- For all other cases, keep looking at parents
6646 -- We fall through the case if we did not yet find the proper
6647 -- place in the free for inserting the freeze node, so climb.
6652 -- If the expression appears in a record or an initialization procedure,
6653 -- the freeze nodes are collected and attached to the current scope, to
6654 -- be inserted and analyzed on exit from the scope, to insure that
6655 -- generated entities appear in the correct scope. If the expression is
6656 -- a default for a discriminant specification, the scope is still void.
6657 -- The expression can also appear in the discriminant part of a private
6658 -- or concurrent type.
6660 -- If the expression appears in a constrained subcomponent of an
6661 -- enclosing record declaration, the freeze nodes must be attached to
6662 -- the outer record type so they can eventually be placed in the
6663 -- enclosing declaration list.
6665 -- The other case requiring this special handling is if we are in a
6666 -- default expression, since in that case we are about to freeze a
6667 -- static type, and the freeze scope needs to be the outer scope, not
6668 -- the scope of the subprogram with the default parameter.
6670 -- For default expressions and other spec expressions in generic units,
6671 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
6672 -- placing them at the proper place, after the generic unit.
6675 or else Freeze_Outside
6680 then
6681 declare
6686 begin
6699 -- The current scope may be that of a constrained component of
6700 -- an enclosing record declaration, or of a loop of an enclosing
6701 -- quantified expression, which is above the current scope in the
6702 -- scope stack. Indeed in the context of a quantified expression,
6703 -- a scope is created and pushed above the current scope in order
6704 -- to emulate the loop-like behavior of the quantified expression.
6705 -- If the expression is within a top-level pragma, as for a pre-
6706 -- condition on a library-level subprogram, nothing to do.
6711 N_Quantified_Expression)
6712 then
6719 Freeze_Nodes;
6720 else
6730 -- Now we have the right place to do the freezing. First, a special
6731 -- adjustment, if we are in spec-expression analysis mode, these freeze
6732 -- actions must not be thrown away (normally all inserted actions are
6733 -- thrown away in this mode. However, the freeze actions are from static
6734 -- expressions and one of the important reasons we are doing this
6735 -- special analysis is to get these freeze actions. Therefore we turn
6736 -- off the In_Spec_Expression mode to propagate these freeze actions.
6737 -- This also means they get properly analyzed and expanded.
6741 -- Freeze the designated type of an allocator (RM 13.14(13))
6747 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
6748 -- the enumeration representation clause exception in the loop above.
6754 -- Freeze name if one is present (RM 13.14(11))
6760 -- Restore In_Spec_Expression flag
6765 -----------------------------
6766 -- Freeze_Fixed_Point_Type --
6767 -----------------------------
6769 -- Certain fixed-point types and subtypes, including implicit base types
6770 -- and declared first subtypes, have not yet set up a range. This is
6771 -- because the range cannot be set until the Small and Size values are
6772 -- known, and these are not known till the type is frozen.
6774 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
6775 -- whose bounds are unanalyzed real literals. This routine will recognize
6776 -- this case, and transform this range node into a properly typed range
6777 -- with properly analyzed and resolved values.
6794 -- Save original bounds (for shaving tests)
6797 -- Actual size chosen
6800 -- Returns size of type with given bounds. Also leaves these
6801 -- bounds set as the current bounds of the Typ.
6803 -----------
6804 -- Fsize --
6805 -----------
6808 begin
6814 -- Start of processing for Freeze_Fixed_Point_Type
6816 begin
6817 -- If Esize of a subtype has not previously been set, set it now
6824 else
6829 -- Immediate return if the range is already analyzed. This means that
6830 -- the range is already set, and does not need to be computed by this
6831 -- routine.
6837 -- Immediate return if either of the bounds raises Constraint_Error
6841 then
6851 -- Ordinary fixed-point case
6855 -- For the ordinary fixed-point case, we are allowed to fudge the
6856 -- end-points up or down by small. Generally we prefer to fudge up,
6857 -- i.e. widen the bounds for non-model numbers so that the end points
6858 -- are included. However there are cases in which this cannot be
6859 -- done, and indeed cases in which we may need to narrow the bounds.
6860 -- The following circuit makes the decision.
6862 -- Note: our terminology here is that Incl_EP means that the bounds
6863 -- are widened by Small if necessary to include the end points, and
6864 -- Excl_EP means that the bounds are narrowed by Small to exclude the
6865 -- end-points if this reduces the size.
6867 -- Note that in the Incl case, all we care about is including the
6868 -- end-points. In the Excl case, we want to narrow the bounds as
6869 -- much as permitted by the RM, to give the smallest possible size.
6886 begin
6887 -- First step. Base types are required to be symmetrical. Right
6888 -- now, the base type range is a copy of the first subtype range.
6889 -- This will be corrected before we are done, but right away we
6890 -- need to deal with the case where both bounds are non-negative.
6891 -- In this case, we set the low bound to the negative of the high
6892 -- bound, to make sure that the size is computed to include the
6893 -- required sign. Note that we do not need to worry about the
6894 -- case of both bounds negative, because the sign will be dealt
6895 -- with anyway. Furthermore we can't just go making such a bound
6896 -- symmetrical, since in a twos-complement system, there is an
6897 -- extra negative value which could not be accommodated on the
6898 -- positive side.
6903 then
6908 -- Compute the fudged bounds. If the number is a model number,
6909 -- then we do nothing to include it, but we are allowed to backoff
6910 -- to the next adjacent model number when we exclude it. If it is
6911 -- not a model number then we straddle the two values with the
6912 -- model numbers on either side.
6918 else
6922 -- The low value excluding the end point is Small greater, but
6923 -- we do not do this exclusion if the low value is positive,
6924 -- since it can't help the size and could actually hurt by
6925 -- crossing the high bound.
6930 -- If the value went from negative to zero, then we have the
6931 -- case where Loval_Incl_EP is the model number just below
6932 -- zero, so we want to stick to the negative value for the
6933 -- base type to maintain the condition that the size will
6934 -- include signed values.
6938 then
6942 else
6946 -- Similar processing for upper bound and high value
6952 else
6958 else
6962 -- One further adjustment is needed. In the case of subtypes, we
6963 -- cannot go outside the range of the base type, or we get
6964 -- peculiarities, and the base type range is already set. This
6965 -- only applies to the Incl values, since clearly the Excl values
6966 -- are already as restricted as they are allowed to be.
6973 -- Get size including and excluding end points
6978 -- No need to exclude end-points if it does not reduce size
6988 -- Now we set the actual size to be used. We want to use the
6989 -- bounds fudged up to include the end-points but only if this
6990 -- can be done without violating a specifically given size
6991 -- size clause or causing an unacceptable increase in size.
6993 -- Case of size clause given
6997 -- Use the inclusive size only if it is consistent with
6998 -- the explicitly specified size.
7005 -- If the inclusive size is too large, we try excluding
7006 -- the end-points (will be caught later if does not work).
7008 else
7014 -- Case of size clause not given
7016 else
7017 -- If we have a base type whose corresponding first subtype
7018 -- has an explicit size that is large enough to include our
7019 -- end-points, then do so. There is no point in working hard
7020 -- to get a base type whose size is smaller than the specified
7021 -- size of the first subtype.
7027 then
7032 -- If excluding the end-points makes the size smaller and
7033 -- results in a size of 8,16,32,64, then we take the smaller
7034 -- size. For the 64 case, this is compulsory. For the other
7035 -- cases, it seems reasonable. We like to include end points
7036 -- if we can, but not at the expense of moving to the next
7037 -- natural boundary of size.
7041 then
7046 -- Otherwise we can definitely include the end points
7048 else
7054 -- One pathological case: normally we never fudge a low bound
7055 -- down, since it would seem to increase the size (if it has
7056 -- any effect), but for ranges containing single value, or no
7057 -- values, the high bound can be small too large. Consider:
7059 -- type t is delta 2.0**(-14)
7060 -- range 131072.0 .. 0;
7062 -- That lower bound is *just* outside the range of 32 bits, and
7063 -- does need fudging down in this case. Note that the bounds
7064 -- will always have crossed here, since the high bound will be
7065 -- fudged down if necessary, as in the case of:
7067 -- type t is delta 2.0**(-14)
7068 -- range 131072.0 .. 131072.0;
7070 -- So we detect the situation by looking for crossed bounds,
7071 -- and if the bounds are crossed, and the low bound is greater
7072 -- than zero, we will always back it off by small, since this
7073 -- is completely harmless.
7080 -- And of course, we need to do exactly the same parallel
7081 -- fudge for flat ranges in the negative region.
7094 -- For the decimal case, none of this fudging is required, since there
7095 -- are no end-point problems in the decimal case (the end-points are
7096 -- always included).
7098 else
7102 -- At this stage, the actual size has been calculated and the proper
7103 -- required bounds are stored in the low and high bounds.
7107 Error_Msg_N
7109 Typ);
7113 -- Check size against explicit given size
7119 Error_Msg_NE
7123 else
7127 -- Increase size to next natural boundary if no size clause given
7129 else
7136 else
7144 -- If we have a base type, then expand the bounds so that they extend to
7145 -- the full width of the allocated size in bits, to avoid junk range
7146 -- checks on intermediate computations.
7153 -- Final step is to reanalyze the bounds using the proper type
7154 -- and set the Corresponding_Integer_Value fields of the literals.
7160 -- Resolve with universal fixed if the base type, and the base type if
7161 -- it is a subtype. Note we can't resolve the base type with itself,
7162 -- that would be a reference before definition.
7166 else
7170 -- Set corresponding integer value for bound
7172 Set_Corresponding_Integer_Value
7175 -- Similar processing for high bound
7183 else
7187 Set_Corresponding_Integer_Value
7190 -- Set type of range to correspond to bounds
7194 -- Set Esize to calculated size if not set already
7200 -- Set RM_Size if not already set. If already set, check value
7202 declare
7205 begin
7210 Error_Msg_NE
7215 else
7220 -- Check for shaving
7224 Error_Msg_N
7226 Error_Msg_N
7231 Error_Msg_N
7233 Error_Msg_N
7239 ------------------
7240 -- Freeze_Itype --
7241 ------------------
7246 begin
7255 --------------------------
7256 -- Freeze_Static_Object --
7257 --------------------------
7262 -- Exception raised if the type of a static object cannot be made
7263 -- static. This happens if the type depends on non-global objects.
7266 -- Called to ensure that an expression used as part of a type definition
7267 -- is statically allocatable, which means that the expression type is
7268 -- statically allocatable, and the expression is either static, or a
7269 -- reference to a library level constant.
7272 -- Called to mark a type as static, checking that it is possible
7273 -- to set the type as static. If it is not possible, then the
7274 -- exception Cannot_Be_Static is raised.
7276 -----------------------------
7277 -- Ensure_Expression_Is_SA --
7278 -----------------------------
7283 begin
7295 then
7303 -----------------------
7304 -- Ensure_Type_Is_SA --
7305 -----------------------
7311 begin
7312 -- If type is library level, we are all set
7318 -- We are also OK if the type already marked as statically allocated,
7319 -- which means we processed it before.
7325 -- Mark type as statically allocated
7329 -- Check that it is safe to statically allocate this type
7347 declare
7351 begin
7363 else
7372 then
7391 else
7396 -- Start of processing for Freeze_Static_Object
7398 begin
7401 exception
7404 -- If the object that cannot be static is imported or exported, then
7405 -- issue an error message saying that this object cannot be imported
7406 -- or exported. If it has an address clause it is an overlay in the
7407 -- current partition and the static requirement is not relevant.
7408 -- Do not issue any error message when ignoring rep clauses.
7415 Error_Msg_N
7419 -- Otherwise must be exported, something is wrong if compiler
7420 -- is marking something as statically allocated which cannot be).
7423 Error_Msg_N
7428 -----------------------
7429 -- Freeze_Subprogram --
7430 -----------------------
7436 begin
7437 -- Subprogram may not have an address clause unless it is imported
7441 Error_Msg_N
7448 -- Reset the Pure indication on an imported subprogram unless an
7449 -- explicit Pure_Function pragma was present or the subprogram is an
7450 -- intrinsic. We do this because otherwise it is an insidious error
7451 -- to call a non-pure function from pure unit and have calls
7452 -- mysteriously optimized away. What happens here is that the Import
7453 -- can bypass the normal check to ensure that pure units call only pure
7454 -- subprograms.
7456 -- The reason for the intrinsic exception is that in general, intrinsic
7457 -- functions (such as shifts) are pure anyway. The only exceptions are
7458 -- the intrinsics in GNAT.Source_Info, and that unit is not marked Pure
7459 -- in any case, so no problem arises.
7465 then
7469 -- For non-foreign convention subprograms, this is where we create
7470 -- the extra formals (for accessibility level and constrained bit
7471 -- information). We delay this till the freeze point precisely so
7472 -- that we know the convention.
7478 -- If this is convention Ada and a Valued_Procedure, that's odd
7483 and then Warn_On_Export_Import
7484 then
7485 Error_Msg_N
7490 -- Case of foreign convention
7492 else
7495 -- For foreign conventions, warn about return of unconstrained array
7500 -- If no return type, probably some other error, e.g. a
7501 -- missing full declaration, so ignore.
7506 -- If the return type is generic, we have emitted a warning
7507 -- earlier on, and there is nothing else to check here. Specific
7508 -- instantiations may lead to erroneous behavior.
7513 -- Display warning if returning unconstrained array
7518 -- Check appropriate warning is enabled (should we check for
7519 -- Warnings (Off) on specific entities here, probably so???)
7521 and then Warn_On_Export_Import
7523 -- Exclude the VM case, since return of unconstrained arrays
7524 -- is properly handled in both the JVM and .NET cases.
7527 then
7528 Error_Msg_N
7535 -- If any of the formals for an exported foreign convention
7536 -- subprogram have defaults, then emit an appropriate warning since
7537 -- this is odd (default cannot be used from non-Ada code)
7542 if Warn_On_Export_Import
7544 then
7545 Error_Msg_N
7555 -- Pragma Inline_Always is disallowed for dispatching subprograms
7556 -- because the address of such subprograms is saved in the dispatch
7557 -- table to support dispatching calls, and dispatching calls cannot
7558 -- be inlined. This is consistent with the restriction against using
7559 -- 'Access or 'Address on an Inline_Always subprogram.
7563 then
7564 Error_Msg_N
7568 -- Because of the implicit representation of inherited predefined
7569 -- operators in the front-end, the overriding status of the operation
7570 -- may be affected when a full view of a type is analyzed, and this is
7571 -- not captured by the analysis of the corresponding type declaration.
7572 -- Therefore the correctness of a not-overriding indicator must be
7573 -- rechecked when the subprogram is frozen.
7577 then
7582 ----------------------
7583 -- Is_Fully_Defined --
7584 ----------------------
7587 begin
7596 then
7597 -- Verify that the record type has no components with private types
7598 -- without completion.
7600 declare
7603 begin
7615 -- For the designated type of an access to subprogram, all types in
7616 -- the profile must be fully defined.
7619 declare
7622 begin
7635 else
7641 ---------------------------------
7642 -- Process_Default_Expressions --
7643 ---------------------------------
7645 procedure Process_Default_Expressions
7648 is
7655 begin
7658 -- A subprogram instance and its associated anonymous subprogram share
7659 -- their signature. The default expression functions are defined in the
7660 -- wrapper packages for the anonymous subprogram, and should not be
7661 -- generated again for the instance.
7666 then
7674 -- We work with a copy of the default expression because we
7675 -- do not want to disturb the original, since this would mess
7676 -- up the conformance checking.
7680 -- The analysis of the expression may generate insert actions,
7681 -- which of course must not be executed. We wrap those actions
7682 -- in a procedure that is not called, and later on eliminated.
7683 -- The following cases have no side-effects, and are analyzed
7684 -- directly.
7688 N_Integer_Literal,
7689 N_Character_Literal,
7690 N_String_Literal,
7691 N_Real_Literal)
7695 then
7696 -- If there is no default function, we must still do a full
7697 -- analyze call on the default value, to ensure that all error
7698 -- checks are performed, e.g. those associated with static
7699 -- evaluation. Note: this branch will always be taken if the
7700 -- analyzer is turned off (but we still need the error checks).
7702 -- Note: the setting of parent here is to meet the requirement
7703 -- that we can only analyze the expression while attached to
7704 -- the tree. Really the requirement is that the parent chain
7705 -- be set, we don't actually need to be in the tree.
7710 -- Default expressions are resolved with their own type if the
7711 -- context is generic, to avoid anomalies with private types.
7715 else
7719 -- If that resolved expression will raise constraint error,
7720 -- then flag the default value as raising constraint error.
7721 -- This allows a proper error message on the calls.
7727 -- If the default is a parameterless call, we use the name of
7728 -- the called function directly, and there is no body to build.
7732 then
7735 -- Else construct and analyze the body of a wrapper procedure
7736 -- that contains an object declaration to hold the expression.
7737 -- Given that this is done only to complete the analysis, it
7738 -- simpler to build a procedure than a function which might
7739 -- involve secondary stack expansion.
7741 else
7744 Dbody :=
7746 Specification =>
7753 Object_Definition =>
7757 Handled_Statement_Sequence =>
7774 ----------------------------------------
7775 -- Set_Component_Alignment_If_Not_Set --
7776 ----------------------------------------
7779 begin
7780 -- Ignore if not base type, subtypes don't need anything
7786 -- Do not override existing representation
7797 else
7798 Set_Component_Alignment
7804 --------------------------
7805 -- Set_SSO_From_Default --
7806 --------------------------
7811 begin
7812 -- Set default SSO for an array or record base type, except in case of
7813 -- a type extension (which always inherits the SSO of its parent type).
7820 then
7821 Reversed :=
7823 or else
7828 -- For a record type, if bit order is specified explicitly,
7829 -- then do not set SSO from default if not consistent. Note that
7830 -- we do not want to look at a Bit_Order attribute definition
7831 -- for a parent: if we were to inherit Bit_Order, then both
7832 -- SSO_Set_*_By_Default flags would have been cleared already
7833 -- (by Inherit_Aspects_At_Freeze_Point).
7835 and then not
7837 and then
7840 then
7841 -- If flags cause reverse storage order, then set the result. Note
7842 -- that we would have ignored the pragma setting the non default
7843 -- storage order in any case, hence the assertion at this point.
7845 pragma Assert
7850 -- For a record type, also set reversed bit order. Note: if a bit
7851 -- order has been specified explicitly, then this is a no-op.
7860 ------------------
7861 -- Undelay_Type --
7862 ------------------
7865 begin
7869 -- Since we don't want T to have a Freeze_Node, we don't want its
7870 -- Full_View or Corresponding_Record_Type to have one either.
7872 -- ??? Fundamentally, this whole handling is unpleasant. What we really
7873 -- want is to be sure that for an Itype that's part of record R and is a
7874 -- subtype of type T, that it's frozen after the later of the freeze
7875 -- points of R and T. We have no way of doing that directly, so what we
7876 -- do is force most such Itypes to be frozen as part of freezing R via
7877 -- this procedure and only delay the ones that need to be delayed
7878 -- (mostly the designated types of access types that are defined as part
7879 -- of the record).
7885 then
7893 then
7898 ------------------
7899 -- Warn_Overlay --
7900 ------------------
7902 procedure Warn_Overlay
7906 is
7908 -- The object to which the address clause applies
7914 begin
7915 -- No warning if address clause overlay warnings are off
7921 -- No warning if there is an explicit initialization
7929 -- We only give the warning for non-imported entities of a type for
7930 -- which a non-null base init proc is defined, or for objects of access
7931 -- types with implicit null initialization, or when Normalize_Scalars
7932 -- applies and the type is scalar or a string type (the latter being
7933 -- tested for because predefined String types are initialized by inline
7934 -- code rather than by an init_proc). Note that we do not give the
7935 -- warning for Initialize_Scalars, since we suppressed initialization
7936 -- in this case. Also, do not warn if Suppress_Initialization is set.
7946 then
7949 then
7954 then
7961 then
7968 -- A function call (most likely to To_Address) is probably not an
7969 -- overlay, so skip warning. Ditto if the function call was inlined
7970 -- and transformed into an entity.
7978 -- If a pragma Import follows, we assume that it is for the current
7979 -- target of the address clause, and skip the warning.
7984 then
7990 Error_Msg_N
7992 Nam);
7993 else
7994 Error_Msg_N
7996 Nam);
7999 -- Add friendly warning if initialization comes from a packed array
8000 -- component.
8003 declare
8006 begin
8011 then
8015 then
8016 Error_Msg_NE
8021 else
8028 Error_Msg_N
8031 Nam);