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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 an atomic type
948 -- or component, or an independent type or component, or a
949 -- by reference type or aliased component (because packing
950 -- does not touch these).
958 then
962 -- We need to identify a component that is an array where
963 -- the index type is an enumeration type with non-standard
964 -- representation, and some bound of the type depends on a
965 -- discriminant.
967 -- This is because gigi computes the size by doing a
968 -- substitution of the appropriate discriminant value in
969 -- the size expression for the base type, and gigi is not
970 -- clever enough to evaluate the resulting expression (which
971 -- involves a call to rep_to_pos) at compile time.
973 -- It would be nice if gigi would either recognize that
974 -- this expression can be computed at compile time, or
975 -- alternatively figured out the size from the subtype
976 -- directly, where all the information is at hand ???
980 then
981 declare
989 begin
996 then
1002 then
1007 then
1017 -- Clearly size of record is not known if the size of one of
1018 -- the components is not known.
1024 -- Accumulate packed size if possible
1028 -- We can only deal with elementary types, since for
1029 -- non-elementary components, alignment enters into the
1030 -- picture, and we don't know enough to handle proper
1031 -- alignment in this context. Packed arrays count as
1032 -- elementary if the representation is a modular type.
1036 and then Present
1038 and then Is_Modular_Integer_Type
1040 then
1041 -- Packed size unknown if we have an atomic type
1042 -- or a by reference type, since the back end
1043 -- knows how these are layed out.
1047 then
1050 -- If RM_Size is known and static, then we can keep
1051 -- accumulating the packed size
1055 -- A little glitch, to be removed sometime ???
1056 -- gigi does not understand zero sizes yet.
1061 -- Normal case where we can keep accumulating the
1062 -- packed array size.
1064 else
1068 -- If we have a field whose RM_Size is not known then
1069 -- we can't figure out the packed size here.
1071 else
1075 -- If we have a non-elementary type we can't figure out
1076 -- the packed array size (alignment issues).
1078 else
1093 -- All other cases, size not known at compile time
1095 else
1100 -------------------------------------
1101 -- Static_Discriminated_Components --
1102 -------------------------------------
1104 function Static_Discriminated_Components
1106 is
1109 begin
1113 then
1127 -- Start of processing for Check_Compile_Time_Size
1129 begin
1133 -----------------------------------
1134 -- Check_Component_Storage_Order --
1135 -----------------------------------
1137 procedure Check_Component_Storage_Order
1142 is
1148 -- Set for the record case, True if Comp starts on a byte boundary
1149 -- (in which case it is allowed to have different storage order).
1152 -- Set True when the component is a nested composite, and it does not
1153 -- have the same scalar storage order as Encl_Type.
1157 begin
1158 -- Record case
1168 else
1169 -- If a component clause is present, check if the component starts
1170 -- on a storage element boundary. Otherwise conservatively assume
1171 -- it does so only in the case where the record is not packed.
1174 Comp_Byte_Aligned :=
1176 else
1183 -- Array case
1185 else
1192 -- Note: the Reverse_Storage_Order flag is set on the base type, but
1193 -- the attribute definition clause is attached to the first subtype.
1196 Comp_ADC := Get_Attribute_Definition_Clause
1198 Attribute_Scalar_Storage_Order);
1201 -- Case of record or array component: check storage order compatibility
1204 Comp_SSO_Differs :=
1206 /=
1209 -- Parent and extension must have same storage order
1213 Error_Msg_N
1218 -- If enclosing composite has explicit SSO then nested composite must
1219 -- have explicit SSO as well.
1225 -- If component and composite SSO differs, check that component
1226 -- falls on byte boundaries and isn't packed.
1230 -- Component SSO differs from enclosing composite:
1232 -- Reject if component is a packed array, as it may be represented
1233 -- as a scalar internally.
1236 Error_Msg_N
1240 -- Reject if composite is a packed array, as it may be rewritten
1241 -- into an array of scalars.
1247 -- Reject if not byte aligned
1250 and then not Comp_Byte_Aligned
1251 then
1252 Error_Msg_N
1258 -- Enclosing type has explicit SSO: non-composite component must not
1259 -- be aliased.
1262 Error_Msg_N
1268 -----------------------------
1269 -- Check_Debug_Info_Needed --
1270 -----------------------------
1273 begin
1278 or else Debug_Generated_Code
1279 or else Debug_Flag_VV
1281 then
1286 -------------------------------
1287 -- Check_Expression_Function --
1288 -------------------------------
1294 -- Function to search for deferred constant
1296 -------------------
1297 -- Find_Constant --
1298 -------------------
1301 begin
1302 -- When a constant is initialized with the result of a dispatching
1303 -- call, the constant declaration is rewritten as a renaming of the
1304 -- displaced function result. This scenario is not a premature use of
1305 -- a constant even though the Has_Completion flag is not set.
1312 N_Object_Declaration
1315 then
1316 Error_Msg_NE
1324 then
1334 -- Start of processing for Check_Expression_Function
1336 begin
1341 then
1346 ----------------------------
1347 -- Check_Strict_Alignment --
1348 ----------------------------
1353 begin
1371 then
1381 -------------------------
1382 -- Check_Unsigned_Type --
1383 -------------------------
1390 begin
1395 -- Do not attempt to analyze case where range was in error
1401 -- The situation that is non trivial is something like
1403 -- subtype x1 is integer range -10 .. +10;
1404 -- subtype x2 is x1 range 0 .. V1;
1405 -- subtype x3 is x2 range V2 .. V3;
1406 -- subtype x4 is x3 range V4 .. V5;
1408 -- where Vn are variables. Here the base type is signed, but we still
1409 -- know that x4 is unsigned because of the lower bound of x2.
1411 -- The only way to deal with this is to look up the ancestor chain
1414 loop
1428 else
1431 -- If no ancestor had a static lower bound, go to base type
1435 -- Note: the reason we still check for a compile time known
1436 -- value for the base type is that at least in the case of
1437 -- generic formals, we can have bounds that fail this test,
1438 -- and there may be other cases in error situations.
1450 then
1460 -------------------------
1461 -- Is_Atomic_Aggregate --
1462 -------------------------
1464 function Is_Atomic_Aggregate
1467 is
1473 begin
1476 -- Array may be qualified, so find outer context
1484 then
1486 New_N :=
1497 else
1502 -----------------------------------------------
1503 -- Explode_Initialization_Compound_Statement --
1504 -----------------------------------------------
1509 begin
1512 then
1515 -- Note that we rewrite Init_Stmts into a NULL statement, rather than
1516 -- just removing it, because Freeze_All may rely on this particular
1517 -- Node_Id still being present in the enclosing list to know where to
1518 -- stop freezing.
1526 ----------------
1527 -- Freeze_All --
1528 ----------------
1530 -- Note: the easy coding for this procedure would be to just build a
1531 -- single list of freeze nodes and then insert them and analyze them
1532 -- all at once. This won't work, because the analysis of earlier freeze
1533 -- nodes may recursively freeze types which would otherwise appear later
1534 -- on in the freeze list. So we must analyze and expand the freeze nodes
1535 -- as they are generated.
1542 -- This is the internal recursive routine that does freezing of entities
1543 -- (but NOT the analysis of default expressions, which should not be
1544 -- recursive, we don't want to analyze those till we are sure that ALL
1545 -- the types are frozen).
1547 --------------------
1548 -- Freeze_All_Ent --
1549 --------------------
1557 -- If freeze nodes are present, insert and analyze, and reset cursor
1558 -- for next insertion.
1560 -------------------
1561 -- Process_Flist --
1562 -------------------
1565 begin
1572 else
1578 -- Start or processing for Freeze_All_Ent
1580 begin
1584 -- If the entity is an inner package which is not a package
1585 -- renaming, then its entities must be frozen at this point. Note
1586 -- that such entities do NOT get frozen at the end of the nested
1587 -- package itself (only library packages freeze).
1589 -- Same is true for task declarations, where anonymous records
1590 -- created for entry parameters must be frozen.
1596 then
1607 then
1614 N_Single_Task_Declaration)
1615 then
1618 End_Scope;
1620 -- For a derived tagged type, we must ensure that all the
1621 -- primitive operations of the parent have been frozen, so that
1622 -- their addresses will be in the parent's dispatch table at the
1623 -- point it is inherited.
1629 then
1630 declare
1637 begin
1644 then
1646 Process_Flist;
1656 Process_Flist;
1658 -- If already frozen, and there are delayed aspects, this is where
1659 -- we do the visibility check for these aspects (see Sem_Ch13 spec
1660 -- for a description of how we handle aspect visibility).
1664 -- Retrieve the visibility to the discriminants in order to
1665 -- analyze properly the aspects.
1669 declare
1672 begin
1678 then
1689 -- If an incomplete type is still not frozen, this may be a
1690 -- premature freezing because of a body declaration that follows.
1691 -- Indicate where the freezing took place. Freezing will happen
1692 -- if the body comes from source, but not if it is internally
1693 -- generated, for example as the body of a type invariant.
1695 -- If the freezing is caused by the end of the current declarative
1696 -- part, it is a Taft Amendment type, and there is no error.
1700 then
1701 declare
1704 begin
1705 -- The presence of a body freezes all entities previously
1706 -- declared in the current list of declarations, but this
1707 -- does not apply if the body does not come from source.
1708 -- A type invariant is transformed into a subprogram body
1709 -- which is placed at the end of the private part of the
1710 -- current package, but this body does not freeze incomplete
1711 -- types that may be declared in this private part.
1714 N_Entry_Body,
1715 N_Package_Body,
1716 N_Protected_Body,
1717 N_Task_Body)
1719 and then
1722 then
1724 Error_Msg_NE
1735 -- Start of processing for Freeze_All
1737 begin
1740 -- Now that all types are frozen, we can deal with default expressions
1741 -- that require us to build a default expression functions. This is the
1742 -- point at which such functions are constructed (after all types that
1743 -- might be used in such expressions have been frozen).
1745 -- For subprograms that are renaming_as_body, we create the wrapper
1746 -- bodies as needed.
1748 -- We also add finalization chains to access types whose designated
1749 -- types are controlled. This is normally done when freezing the type,
1750 -- but this misses recursive type definitions where the later members
1751 -- of the recursion introduce controlled components.
1753 -- Loop through entities
1768 else
1774 and then
1776 = N_Subprogram_Renaming_Declaration
1777 then
1778 Build_And_Analyze_Renamed_Body
1785 N_Single_Task_Declaration)
1786 then
1787 declare
1790 begin
1795 then
1804 -- Historical note: We used to create a finalization master for an
1805 -- access type whose designated type is not controlled, but contains
1806 -- private controlled compoments. This form of postprocessing is no
1807 -- longer needed because the finalization master is now created when
1808 -- the access type is frozen (see Exp_Ch3.Freeze_Type).
1814 -----------------------
1815 -- Freeze_And_Append --
1816 -----------------------
1818 procedure Freeze_And_Append
1822 is
1824 begin
1828 else
1834 -------------------
1835 -- Freeze_Before --
1836 -------------------
1841 begin
1851 -------------------
1852 -- Freeze_Entity --
1853 -------------------
1857 -- Save the current Ghost mode in effect in case the entity being frozen
1858 -- sets a different mode.
1868 -- This could use a comment ???
1871 -- Used to detect attempt to freeze function declared in another unit
1874 -- List of freezing actions, left at No_List if none
1877 -- This flag gets set to true for a variable with default initialization
1880 -- N is a freezing action to be appended to the Result
1883 -- If Loc is a freeze_entity that appears after the last declaration
1884 -- in the scope, inhibit error messages on late completion.
1887 -- Check that an Access or Unchecked_Access attribute with a prefix
1888 -- which is the current instance type can only be applied when the type
1889 -- is limited.
1892 -- Give warning for modulus of 8, 16, 32, or 64 given as an explicit
1893 -- integer literal without an explicit corresponding size clause. The
1894 -- caller has checked that Utype is a modular integer type.
1897 -- Freeze array type, including freezing index and component types
1900 -- Create Freeze_Generic_Entity nodes for types declared in a generic
1901 -- package. Recurse on inner generic packages.
1904 -- Freeze formals and return type of subprogram. If some type in the
1905 -- profile is a limited view, freezing of the entity will take place
1906 -- elsewhere, and the function returns False. This routine will be
1907 -- modified if and when we can implement AI05-019 efficiently ???
1910 -- Freeze record type, including freezing component types, and freezing
1911 -- primitive operations if this is a tagged type.
1914 -- Determine whether an arbitrary entity is subject to Boolean aspect
1915 -- Import and its value is specified as True.
1918 -- Following AI05-151, a function can return a limited view of a type
1919 -- declared elsewhere. In that case the function cannot be frozen at
1920 -- the end of its enclosing package. If its first use is in a different
1921 -- unit, it cannot be frozen there, but if the call is legal the full
1922 -- view of the return type is available and the subprogram can now be
1923 -- frozen. However the freeze node cannot be inserted at the point of
1924 -- call, but rather must go in the package holding the function, so that
1925 -- the backend can process it in the proper context.
1928 -- Restore the values of all saved global variables
1931 -- If E is an entity for an imported subprogram with pre/post-conditions
1932 -- then this procedure will create a wrapper to ensure that proper run-
1933 -- time checking of the pre/postconditions. See body for details.
1935 -------------------
1936 -- Add_To_Result --
1937 -------------------
1940 begin
1943 else
1948 ----------------------------
1949 -- After_Last_Declaration --
1950 ----------------------------
1955 begin
1961 else
1965 else
1970 ----------------------------
1971 -- Check_Current_Instance --
1972 ----------------------------
1977 -- Determine whether Typ is compatible with the rules for aliased
1978 -- views of types as defined in RM 3.10 in the various dialects.
1981 -- Process routine to apply check to given node
1983 -----------------------------
1984 -- Is_Aliased_View_Of_Type --
1985 -----------------------------
1990 begin
1991 -- Common case
1995 then
1998 -- The following paragraphs describe what a legal aliased view of
1999 -- a type is in the various dialects of Ada.
2001 -- Ada 95
2003 -- The current instance of a limited type, and a formal parameter
2004 -- or generic formal object of a tagged type.
2006 -- Ada 95 limited type
2007 -- * Type with reserved word "limited"
2008 -- * A protected or task type
2009 -- * A composite type with limited component
2014 -- Ada 2005
2016 -- The current instance of a limited tagged type, a protected
2017 -- type, a task type, or a type that has the reserved word
2018 -- "limited" in its full definition ... a formal parameter or
2019 -- generic formal object of a tagged type.
2021 -- Ada 2005 limited type
2022 -- * Type with reserved word "limited", "synchronized", "task"
2023 -- or "protected"
2024 -- * A composite type with limited component
2025 -- * A derived type whose parent is a non-interface limited type
2028 return
2030 or else
2035 -- Ada 2012 and beyond
2037 -- The current instance of an immutably limited type ... a formal
2038 -- parameter or generic formal object of a tagged type.
2040 -- Ada 2012 limited type
2041 -- * Type with reserved word "limited", "synchronized", "task"
2042 -- or "protected"
2043 -- * A composite type with limited component
2044 -- * A derived type whose parent is a non-interface limited type
2045 -- * An incomplete view
2047 -- Ada 2012 immutably limited type
2048 -- * Explicitly limited record type
2049 -- * Record extension with "limited" present
2050 -- * Non-formal limited private type that is either tagged
2051 -- or has at least one access discriminant with a default
2052 -- expression
2053 -- * Task type, protected type or synchronized interface
2054 -- * Type derived from immutably limited type
2056 else
2057 return
2063 -------------
2064 -- Process --
2065 -------------
2068 begin
2072 Name_Unchecked_Access)
2076 then
2078 Error_Msg_N
2081 else
2082 Error_Msg_N
2089 else
2099 -- Local variables
2104 -- Start of processing for Check_Current_Instance
2106 begin
2112 ------------------------------
2113 -- Check_Suspicious_Modulus --
2114 ------------------------------
2119 begin
2125 declare
2128 begin
2130 declare
2134 begin
2136 declare
2140 begin
2141 -- First case, modulus and size are the same. This
2142 -- happens if you have something like mod 32, with
2143 -- an explicit size of 32, this is for sure a case
2144 -- where the warning is given, since it is seems
2145 -- very unlikely that someone would want e.g. a
2146 -- five bit type stored in 32 bits. It is much
2147 -- more likely they wanted a 32-bit type.
2152 -- Second case, the modulus is 32 or 64 and no
2153 -- size clause is present. This is a less clear
2154 -- case for giving the warning, but in the case
2155 -- of 32/64 (5-bit or 6-bit types) these seem rare
2156 -- enough that it is a likely error (and in any
2157 -- case using 2**5 or 2**6 in these cases seems
2158 -- clearer. We don't include 8 or 16 here, simply
2159 -- because in practice 3-bit and 4-bit types are
2160 -- more common and too many false positives if
2161 -- we warn in these cases.
2165 then
2168 -- No warning needed
2170 else
2174 -- If we fall through, give warning
2177 Error_Msg_N
2179 Modulus);
2188 -----------------------
2189 -- Freeze_Array_Type --
2190 -----------------------
2198 -- Set true if any of the index types is an enumeration type with a
2199 -- non-standard representation.
2201 begin
2210 then
2217 -- Processing that is done only for base types
2221 -- Deal with default setting of reverse storage order
2225 -- Propagate flags for component type
2229 then
2237 -- Warn for pragma Pack overriding foreign convention
2241 then
2242 declare
2247 begin
2251 Error_Msg_N
2254 Error_Msg_N
2261 -- If packing was requested or if the component size was
2262 -- set explicitly, then see if bit packing is required. This
2263 -- processing is only done for base types, since all of the
2264 -- representation aspects involved are type-related.
2266 -- This is not just an optimization, if we start processing the
2267 -- subtypes, they interfere with the settings on the base type
2268 -- (this is because Is_Packed has a slightly different meaning
2269 -- before and after freezing).
2271 declare
2275 begin
2279 then
2288 else
2291 -- We can set the component size if it is less than 16,
2292 -- rounding it up to the next storage unit size.
2298 else
2302 -- Set component size up to match alignment if it would
2303 -- otherwise be less than the alignment. This deals with
2304 -- cases of types whose alignment exceeds their size (the
2305 -- padded type cases).
2308 declare
2310 begin
2318 -- Case of component size that may result in packing
2321 declare
2327 Get_Attribute_Definition_Clause
2330 begin
2331 -- Warn if we have pack and component size so that the
2332 -- pack is ignored.
2334 -- Note: here we must check for the presence of a
2335 -- component size before checking for a Pack pragma to
2336 -- deal with the case where the array type is a derived
2337 -- type whose parent is currently private.
2341 and then Warn_On_Redundant_Constructs
2342 then
2344 Error_Msg_NE
2346 Error_Msg_N
2352 -- Set component size if not already set by a component
2353 -- size clause.
2359 -- Check for base type of 8, 16, 32 bits, where an
2360 -- unsigned subtype has a length one less than the
2361 -- base type (e.g. Natural subtype of Integer).
2363 -- In such cases, if a component size was not set
2364 -- explicitly, then generate a warning.
2370 then
2374 Error_Msg_N
2376 Pack_Pragma);
2377 Error_Msg_N
2379 Pack_Pragma);
2383 -- Actual packing is not needed for 8, 16, 32, 64. Also
2384 -- not needed for 24 if alignment is 1.
2391 then
2392 -- Here the array was requested to be packed, but
2393 -- the packing request had no effect, so Is_Packed
2394 -- is reset.
2396 -- Note: semantically this means that we lose track
2397 -- of the fact that a derived type inherited a pragma
2398 -- Pack that was non- effective, but that seems fine.
2400 -- We regard a Pack pragma as a request to set a
2401 -- representation characteristic, and this request
2402 -- may be ignored.
2409 then
2413 -- In all other cases, packing is indeed needed
2415 else
2424 -- Check for Aliased or Atomic_Components/Atomic with unsuitable
2425 -- packing or explicit component size clause given.
2430 and then
2432 then
2436 -- Outputs error messages for incorrect CS clause or pragma
2437 -- Pack for aliased or atomic components (T is "aliased" or
2438 -- "atomic");
2440 -----------------
2441 -- Complain_CS --
2442 -----------------
2445 begin
2447 Clause :=
2448 Get_Attribute_Definition_Clause
2451 Error_Msg_N
2455 Error_Msg_N
2458 else
2459 Error_Msg_N
2465 -- Start of processing for Alias_Atomic_Check
2467 begin
2468 -- If object size of component type isn't known, we cannot
2469 -- be sure so we defer to the back end.
2474 -- Case where component size has no effect. First check for
2475 -- object size of component type multiple of the storage
2476 -- unit size.
2480 -- OK in both packing case and component size case if RM
2481 -- size is known and static and same as the object size.
2483 and then
2487 -- Or if we have an explicit component size clause and
2488 -- the component size and object size are equal.
2490 or else
2493 then
2500 then
2506 -- Check for Independent_Components/Independent with unsuitable
2507 -- packing or explicit component size clause given.
2510 and then
2512 then
2513 begin
2514 -- If object size of component type isn't known, we cannot
2515 -- be sure so we defer to the back end.
2520 -- Case where component size has no effect. First check for
2521 -- object size of component type multiple of the storage
2522 -- unit size.
2526 -- OK in both packing case and component size case if RM
2527 -- size is known and multiple of the storage unit size.
2529 and then
2533 -- Or if we have an explicit component size clause and
2534 -- the component size is larger than the object size.
2536 or else
2539 then
2542 else
2544 Clause :=
2545 Get_Attribute_Definition_Clause
2548 Error_Msg_N
2552 Error_Msg_N
2555 else
2556 Error_Msg_N
2564 -- Warn for case of atomic type
2570 then
2571 Error_Msg_NE
2586 -- Check for scalar storage order
2588 declare
2590 begin
2591 Check_Component_Storage_Order
2594 ADC => Get_Attribute_Definition_Clause
2596 Attribute_Scalar_Storage_Order),
2600 -- Processing that is done only for subtypes
2602 else
2603 -- Acquire alignment from base type
2611 -- Specific checks for bit-packed arrays
2615 -- Check number of elements for bit packed arrays that come from
2616 -- source and have compile time known ranges. The bit-packed
2617 -- arrays circuitry does not support arrays with more than
2618 -- Integer'Last + 1 elements, and when this restriction is
2619 -- violated, causes incorrect data access.
2621 -- For the case where this is not compile time known, a run-time
2622 -- check should be generated???
2625 declare
2631 begin
2637 -- Never generate an error if any index is of a generic
2638 -- type. We will check this in instances.
2645 Ilen :=
2651 -- No attempt is made to check number of elements if not
2652 -- compile time known.
2665 then
2666 Error_Msg_N
2673 -- Check size
2676 declare
2680 begin
2681 -- It is not clear if it is possible to have no size clause
2682 -- at this stage, but it is not worth worrying about. Post
2683 -- error on the entity name in the size clause if present,
2684 -- else on the type entity itself.
2688 else
2695 -- If any of the index types was an enumeration type with a non-
2696 -- standard rep clause, then we indicate that the array type is
2697 -- always packed (even if it is not bit packed).
2706 -- If the array is packed, we must create the packed array type to be
2707 -- used to actually implement the type. This is only needed for real
2708 -- array types (not for string literal types, since they are present
2709 -- only for the front end).
2713 then
2717 -- Make sure that we have the necessary routines to implement the
2718 -- packing, and complain now if not. Note that we only test this
2719 -- for constrained array types.
2725 then
2726 declare
2730 begin
2733 then
2734 Error_Msg_CRT
2738 -- Cancel the packing
2748 -- Size information of packed array type is copied to the array
2749 -- type, since this is really the representation. But do not
2750 -- override explicit existing size values. If the ancestor subtype
2751 -- is constrained the Packed_Array_Impl_Type will be inherited
2752 -- from it, but the size may have been provided already, and
2753 -- must not be overridden either.
2756 and then
2759 then
2771 -- For non-packed arrays set the alignment of the array to the
2772 -- alignment of the component type if it is unknown. Skip this
2773 -- in atomic case (atomic arrays may need larger alignments).
2782 then
2787 -----------------------------
2788 -- Freeze_Generic_Entities --
2789 -----------------------------
2796 begin
2815 --------------------
2816 -- Freeze_Profile --
2817 --------------------
2824 begin
2825 -- Loop through formals
2831 -- AI05-0151: incomplete types can appear in a profile. By the
2832 -- time the entity is frozen, the full view must be available,
2833 -- unless it is a limited view.
2838 then
2850 then
2851 -- If the type of a formal is incomplete, subprogram is being
2852 -- frozen prematurely. Within an instance (but not within a
2853 -- wrapper package) this is an artifact of our need to regard
2854 -- the end of an instantiation as a freeze point. Otherwise it
2855 -- is a definite error.
2862 elsif not After_Last_Declaration
2863 and then not Freezing_Library_Level_Tagged_Type
2864 then
2866 Error_Msg
2871 -- Check suspicious parameter for C function. These tests apply
2872 -- only to exported/imported subprograms.
2874 if Warn_On_Export_Import
2877 or else
2884 then
2885 -- Qualify mention of formals with subprogram name
2889 -- Check suspicious use of fat C pointer
2893 then
2894 Error_Msg_N
2897 -- Check suspicious return of boolean
2904 then
2905 Error_Msg_N
2907 Error_Msg_N
2911 -- Check suspicious tagged type
2914 or else
2918 then
2919 Error_Msg_N
2923 -- Check wrong convention subprogram pointer
2927 then
2928 Error_Msg_N
2932 Error_Msg_NE
2937 -- Turn off name qualification after message output
2942 -- Check for unconstrained array in exported foreign convention
2943 -- case.
2949 and then Warn_On_Export_Import
2951 -- Exclude VM case, since both .NET and JVM can handle
2952 -- unconstrained arrays without a problem.
2955 then
2958 -- If this is an inherited operation, place the warning on
2959 -- the derived type declaration, rather than on the original
2960 -- subprogram.
2963 then
2969 else
2985 -- If the formal is an anonymous_access_to_subprogram
2986 -- freeze the subprogram type as well, to prevent
2987 -- scope anomalies in gigi, because there is no other
2988 -- clear point at which it could be frozen.
2992 then
3000 -- Case of function: similar checks on return type
3004 -- Check whether function is declared elsewhere.
3006 Late_Freezing :=
3011 -- Freeze return type
3015 -- AI05-0151: the return type may have been incomplete
3016 -- at the point of declaration. Replace it with the full
3017 -- view, unless the current type is a limited view. In
3018 -- that case the full view is in a different unit, and
3019 -- gigi finds the non-limited view after the other unit
3020 -- is elaborated.
3025 then
3029 -- If the return type is a limited view and the non-limited
3030 -- view is still incomplete, the function has to be frozen at a
3031 -- later time. If the function is abstract there is no place at
3032 -- which the full view will become available, and no code to be
3033 -- generated for it, so mark type as frozen.
3038 then
3041 else
3050 -- Check suspicious return type for C function
3052 if Warn_On_Export_Import
3054 or else
3057 then
3058 -- Check suspicious return of fat C pointer
3064 then
3068 -- Check suspicious return of boolean
3076 then
3077 declare
3080 begin
3081 Error_Msg_NE
3083 Error_Msg_NE
3088 -- Check suspicious return tagged type
3092 and then
3093 Is_Tagged_Type
3098 then
3102 -- Check return of wrong convention subprogram pointer
3108 then
3112 Error_Msg_NE
3118 -- Give warning for suspicious return of a result of an
3119 -- unconstrained array type in a foreign convention function.
3123 -- We are looking for a return of unconstrained array
3128 -- Exclude imported routines, the warning does not belong on
3129 -- the import, but rather on the routine definition.
3133 -- Exclude VM case, since both .NET and JVM can handle return
3134 -- of unconstrained arrays without a problem.
3138 -- Check that general warning is enabled, and that it is not
3139 -- suppressed for this particular case.
3141 and then Warn_On_Export_Import
3144 then
3150 -- Check suspicious use of Import in pure unit
3154 -- Ignore internally generated entity. This happens in some cases
3155 -- of subprograms in specs, where we generate an implied body.
3159 -- Assume run-time knows what it is doing
3161 and then not GNAT_Mode
3163 -- Assume explicit Pure_Function means import is pure
3167 -- Don't need warning in relaxed semantics mode
3169 and then not Relaxed_RM_Semantics
3171 -- Assume convention Intrinsic is OK, since this is specialized.
3172 -- This deals with the DEC unit current_exception.ads
3176 -- Assume that ASM interface knows what it is doing. This deals
3177 -- with unsigned.ads in the AAMP back end.
3180 then
3181 Error_Msg_N
3183 Error_Msg_NE
3191 ------------------------
3192 -- Freeze_Record_Type --
3193 ------------------------
3205 -- Set True if the record type scope Rec has been pushed on the scope
3206 -- stack. Needed for the analysis of delayed aspects specified to the
3207 -- components of Rec.
3210 -- Scalar_Storage_Order attribute definition clause for the record
3213 -- Set True if we find at least one component with no component
3214 -- clause (used to warn about useless Pack pragmas).
3217 -- Set True if we find at least one component with a component
3218 -- clause (used to warn about useless Bit_Order pragmas, and also
3219 -- to detect cases where Implicit_Packing may have an effect).
3222 -- Set True if we find at least one component which is aliased. This
3223 -- is used to prevent Implicit_Packing of the record, since packing
3224 -- cannot modify the size of alignment of an aliased component.
3227 -- Set True if we find at least one component whose type has a
3228 -- Scalar_Storage_Order attribute definition clause.
3231 -- Set False if we encounter a component of a non-scalar type
3235 -- Accumulates total RM_Size values and total Esize values of all
3236 -- scalar components. Used for processing of Implicit_Packing.
3239 -- If N is an allocator, possibly wrapped in one or more level of
3240 -- qualified expression(s), return the inner allocator node, else
3241 -- return Empty.
3244 -- If the component subtype is an access to a constrained subtype of
3245 -- an already frozen type, make the subtype frozen as well. It might
3246 -- otherwise be frozen in the wrong scope, and a freeze node on
3247 -- subtype has no effect. Similarly, if the component subtype is a
3248 -- regular (not protected) access to subprogram, set the anonymous
3249 -- subprogram type to frozen as well, to prevent an out-of-scope
3250 -- freeze node at some eventual point of call. Protected operations
3251 -- are handled elsewhere.
3254 -- Make sure that all types mentioned in Discrete_Choices of the
3255 -- variants referenceed by the Variant_Part VP are frozen. This is
3256 -- a recursive routine to deal with nested variants.
3258 ---------------------
3259 -- Check_Allocator --
3260 ---------------------
3264 begin
3266 loop
3271 else
3277 -----------------
3278 -- Check_Itype --
3279 -----------------
3284 begin
3287 then
3290 -- In addition, add an Itype_Reference to ensure that the
3291 -- access subtype is elaborated early enough. This cannot be
3292 -- done if the subtype may depend on discriminants.
3297 then
3305 then
3310 ------------------------------------
3311 -- Freeze_Choices_In_Variant_Part --
3312 ------------------------------------
3321 begin
3322 -- Loop through variants
3327 -- Loop through choices, checking that all types are frozen
3333 then
3340 -- Check for nested variant part to process
3354 -- Start of processing for Freeze_Record_Type
3356 begin
3357 -- Deal with delayed aspect specifications for components. The
3358 -- analysis of the aspect is required to be delayed to the freeze
3359 -- point, thus we analyze the pragma or attribute definition
3360 -- clause in the tree at this point. We also analyze the aspect
3361 -- specification node at the freeze point when the aspect doesn't
3362 -- correspond to pragma/attribute definition clause.
3368 then
3373 -- The visibility to the discriminants must be restored in
3374 -- order to properly analyze the aspects.
3387 -- Pop the scope if Rec scope has been pushed on the scope stack
3388 -- during the delayed aspect analysis process.
3395 Pop_Scope;
3398 -- Freeze components and embedded subtypes
3407 -- Handle the component and discriminant case
3410 declare
3413 begin
3414 -- Freezing a record type freezes the type of each of its
3415 -- components. However, if the type of the component is
3416 -- part of this record, we do not want or need a separate
3417 -- Freeze_Node. Note that Is_Itype is wrong because that's
3418 -- also set in private type cases. We also can't check for
3419 -- the Scope being exactly Rec because of private types and
3420 -- record extensions.
3425 then
3431 -- Warn for pragma Pack overriding foreign convention
3436 -- Don't warn for aliased components, since override
3437 -- cannot happen in that case.
3440 then
3441 declare
3446 begin
3450 Error_Msg_N
3452 PP);
3454 Error_Msg_NE
3461 -- Check for error of component clause given for variable
3462 -- sized type. We have to delay this test till this point,
3463 -- since the component type has to be frozen for us to know
3464 -- if it is variable length.
3469 -- We omit this test in a generic context, it will be
3470 -- applied at instantiation time.
3475 -- Also omit this test in CodePeer mode, since we do not
3476 -- have sufficient info on size and rep clauses.
3481 -- Omit check if component has a generic type. This can
3482 -- happen in an instantiation within a generic in ASIS
3483 -- mode, where we force freeze actions without full
3484 -- expansion.
3489 -- Do the check
3491 elsif not
3492 Size_Known_At_Compile_Time
3494 then
3495 Error_Msg_N
3500 else
3504 -- Case of component requires byte alignment
3508 -- Set the enclosing record to also require byte align
3512 -- Check for component clause that is inconsistent with
3513 -- the required byte boundary alignment.
3518 then
3519 Error_Msg_N
3527 -- Gather data for possible Implicit_Packing later. Note that at
3528 -- this stage we might be dealing with a real component, or with
3529 -- an implicit subtype declaration.
3533 else
3534 Scalar_Component_Total_RM_Size :=
3536 Scalar_Component_Total_Esize :=
3540 -- If the component is an Itype with Delayed_Freeze and is either
3541 -- a record or array subtype and its base type has not yet been
3542 -- frozen, we must remove this from the entity list of this record
3543 -- and put it on the entity list of the scope of its base type.
3544 -- Note that we know that this is not the type of a component
3545 -- since we cleared Has_Delayed_Freeze for it in the previous
3546 -- loop. Thus this must be the Designated_Type of an access type,
3547 -- which is the type of a component.
3555 then
3556 declare
3560 begin
3561 -- We have a difficult case to handle here. Suppose Rec is
3562 -- subtype being defined in a subprogram that's created as
3563 -- part of the freezing of Rec'Base. In that case, we know
3564 -- that Comp'Base must have already been frozen by the time
3565 -- we get to elaborate this because Gigi doesn't elaborate
3566 -- any bodies until it has elaborated all of the declarative
3567 -- part. But Is_Frozen will not be set at this point because
3568 -- we are processing code in lexical order.
3570 -- We detect this case by going up the Scope chain of Rec
3571 -- and seeing if we have a subprogram scope before reaching
3572 -- the top of the scope chain or that of Comp'Base. If we
3573 -- do, then mark that Comp'Base will actually be frozen. If
3574 -- so, we merely undelay it.
3591 else
3594 else
3598 -- Insert in entity list of scope of base type (which
3599 -- must be an enclosing scope, because still unfrozen).
3605 -- If the component is an access type with an allocator as default
3606 -- value, the designated type will be frozen by the corresponding
3607 -- expression in init_proc. In order to place the freeze node for
3608 -- the designated type before that for the current record type,
3609 -- freeze it now.
3611 -- Same process if the component is an array of access types,
3612 -- initialized with an aggregate. If the designated type is
3613 -- private, it cannot contain allocators, and it is premature
3614 -- to freeze the type, so we check for this as well.
3619 then
3620 declare
3624 begin
3627 -- If component is pointer to a class-wide type, freeze
3628 -- the specific type in the expression being allocated.
3629 -- The expression may be a subtype indication, in which
3630 -- case freeze the subtype mark.
3632 if Is_Class_Wide_Type
3634 then
3636 Freeze_And_Append
3640 then
3641 Freeze_And_Append
3649 else
3650 Freeze_And_Append
3658 then
3661 -- Freeze the designated type when initializing a component with
3662 -- an aggregate in case the aggregate contains allocators.
3664 -- type T is ...;
3665 -- type T_Ptr is access all T;
3666 -- type T_Array is array ... of T_Ptr;
3668 -- type Rec is record
3669 -- Comp : T_Array := (others => ...);
3670 -- end record;
3674 then
3675 declare
3678 Designated_Type
3681 begin
3682 -- The only case when this sort of freezing is not done is
3683 -- when the designated type is class-wide and the root type
3684 -- is the record owning the component. This scenario results
3685 -- in a circularity because the class-wide type requires
3686 -- primitives that have not been created yet as the root
3687 -- type is in the process of being frozen.
3689 -- type Rec is tagged;
3690 -- type Rec_Ptr is access all Rec'Class;
3691 -- type Rec_Array is array ... of Rec_Ptr;
3693 -- type Rec is record
3694 -- Comp : Rec_Array := (others => ...);
3695 -- end record;
3699 then
3707 then
3717 -- Deal with default setting of reverse storage order
3721 -- Check consistent attribute setting on component types
3723 SSO_ADC := Get_Attribute_Definition_Clause
3726 declare
3728 begin
3731 Check_Component_Storage_Order
3741 -- Now deal with reverse storage order/bit order issues
3745 -- Check compatibility of Scalar_Storage_Order with Bit_Order, if
3746 -- the former is specified.
3750 -- Note: report error on Rec, not on SSO_ADC, as ADC may apply
3751 -- to some ancestor type.
3754 Error_Msg_N
3759 -- Warn if there is an Scalar_Storage_Order attribute definition
3760 -- clause but no component clause, no component that itself has
3761 -- such an attribute definition, and no pragma Pack.
3764 or else
3765 SSO_ADC_Component
3766 or else
3768 then
3769 Error_Msg_N
3771 SSO_ADC);
3775 -- Deal with Bit_Order aspect
3783 then
3784 -- Warn if clause has no effect when no component clause is
3785 -- present, but suppress warning if the Bit_Order is required
3786 -- due to the presence of a Scalar_Storage_Order attribute.
3788 Error_Msg_N
3790 Error_Msg_N
3793 -- Here is where we do the processing to adjust component clauses
3794 -- for reversed bit order, when not using reverse SSO.
3798 then
3801 -- Case where we have both an explicit Bit_Order and the same
3802 -- Scalar_Storage_Order: leave record untouched, the back-end
3803 -- will take care of required layout conversions.
3805 else
3811 -- Complete error checking on record representation clause (e.g.
3812 -- overlap of components). This is called after adjusting the
3813 -- record for reverse bit order.
3815 declare
3817 begin
3823 -- Set OK_To_Reorder_Components depending on debug flags
3827 or else
3829 then
3834 -- Check for useless pragma Pack when all components placed. We only
3835 -- do this check for record types, not subtypes, since a subtype may
3836 -- have all its components placed, and it still makes perfectly good
3837 -- sense to pack other subtypes or the parent type. We do not give
3838 -- this warning if Optimize_Alignment is set to Space, since the
3839 -- pragma Pack does have an effect in this case (it always resets
3840 -- the alignment to one).
3844 and then not Unplaced_Component
3846 then
3847 -- Reset packed status. Probably not necessary, but we do it so
3848 -- that there is no chance of the back end doing something strange
3849 -- with this redundant indication of packing.
3853 -- Give warning if redundant constructs warnings on
3856 Error_Msg_N -- CODEFIX
3862 -- If this is the record corresponding to a remote type, freeze the
3863 -- remote type here since that is what we are semantically freezing.
3864 -- This prevents the freeze node for that type in an inner scope.
3871 -- Check for controlled components and unchecked unions.
3876 -- Do not set Has_Controlled_Component on a class-wide
3877 -- equivalent type. See Make_CW_Equivalent_Type.
3880 and then
3882 or else
3885 or else
3887 and then
3889 and then
3890 Has_Controlled_Component
3892 then
3900 -- Scan component declaration for likely misuses of current
3901 -- instance, either in a constraint or a default expression.
3911 -- Enforce the restriction that access attributes with a current
3912 -- instance prefix can only apply to limited types. This comment
3913 -- is floating here, but does not seem to belong here???
3915 -- Set component alignment if not otherwise already set
3919 -- For first subtypes, check if there are any fixed-point fields with
3920 -- component clauses, where we must check the size. This is not done
3921 -- till the freeze point since for fixed-point types, we do not know
3922 -- the size until the type is frozen. Similar processing applies to
3923 -- bit packed arrays.
3931 then
3932 Check_Size
3936 Junk);
3943 -- Generate warning for applying C or C++ convention to a record
3944 -- with discriminants. This is suppressed for the unchecked union
3945 -- case, since the whole point in this case is interface C. We also
3946 -- do not generate this within instantiations, since we will have
3947 -- generated a message on the template.
3952 or else
3955 and then not In_Instance
3958 then
3959 declare
3963 begin
3968 Error_Msg_N
3970 A2);
3971 else
3972 Error_Msg_N
3974 A2);
3977 Error_Msg_NE
3983 -- See if Size is too small as is (and implicit packing might help)
3987 -- No implicit packing if even one component is explicitly placed
3989 and then not Placed_Component
3991 -- Or even one component is aliased
3993 and then not Aliased_Component
3995 -- Must have size clause and all scalar components
3998 and then All_Scalar_Components
4000 -- Do not try implicit packing on records with discriminants, too
4001 -- complicated, especially in the variant record case.
4005 -- We can implicitly pack if the specified size of the record is
4006 -- less than the sum of the object sizes (no point in packing if
4007 -- this is not the case).
4011 -- And the total RM size cannot be greater than the specified size
4012 -- since otherwise packing will not get us where we have to be.
4016 -- Never do implicit packing in CodePeer or SPARK modes since
4017 -- we don't do any packing in these modes, since this generates
4018 -- over-complex code that confuses static analysis, and in
4019 -- general, neither CodePeer not GNATprove care about the
4020 -- internal representation of objects.
4023 then
4024 -- If implicit packing enabled, do it
4029 -- Otherwise flag the size clause
4031 else
4032 declare
4034 begin
4035 Error_Msg_NE -- CODEFIX
4037 Error_Msg_N -- CODEFIX
4044 -- The following checks are only relevant when SPARK_Mode is on as
4045 -- they are not standard Ada legality rules.
4050 -- A discriminated type cannot be effectively volatile
4051 -- (SPARK RM C.6(4)).
4056 -- A tagged type cannot be effectively volatile
4057 -- (SPARK RM C.6(5)).
4063 -- A non-effectively volatile record type cannot contain
4064 -- effectively volatile components (SPARK RM C.6(2)).
4066 else
4071 then
4073 Error_Msg_N
4083 -- All done if not a full record definition
4089 -- Finally we need to check the variant part to make sure that
4090 -- all types within choices are properly frozen as part of the
4091 -- freezing of the record type.
4098 begin
4099 -- Find component list
4111 then
4116 -- Case of variant part present
4122 -- Note: we used to call Check_Choices here, but it is too early,
4123 -- since predicated subtypes are frozen here, but their freezing
4124 -- actions are in Analyze_Freeze_Entity, which has not been called
4125 -- yet for entities frozen within this procedure, so we moved that
4126 -- call to the Analyze_Freeze_Entity for the record type.
4130 -- Check that all the primitives of an interface type are abstract
4131 -- or null procedures.
4135 then
4136 declare
4140 begin
4147 -- Avoid reporting the error on inherited primitives
4150 then
4155 Error_Msg_N
4159 else
4160 Error_Msg_N
4172 -------------------------------
4173 -- Has_Boolean_Aspect_Import --
4174 -------------------------------
4181 begin
4187 -- The value of aspect Import is True when the expression is
4188 -- either missing or it is explicitly set to True.
4194 then
4205 ----------------------------
4206 -- Late_Freeze_Subprogram --
4207 ----------------------------
4214 begin
4217 else
4224 ---------------------
4225 -- Restore_Globals --
4226 ---------------------
4229 begin
4233 ------------------------------
4234 -- Wrap_Imported_Subprogram --
4235 ------------------------------
4237 -- The issue here is that our normal approach of checking preconditions
4238 -- and postconditions does not work for imported procedures, since we
4239 -- are not generating code for the body. To get around this we create
4240 -- a wrapper, as shown by the following example:
4242 -- procedure K (A : Integer);
4243 -- pragma Import (C, K);
4245 -- The spec is rewritten by removing the effects of pragma Import, but
4246 -- leaving the convention unchanged, as though the source had said:
4248 -- procedure K (A : Integer);
4249 -- pragma Convention (C, K);
4251 -- and we create a body, added to the entity K freeze actions, which
4252 -- looks like:
4254 -- procedure K (A : Integer) is
4255 -- procedure K (A : Integer);
4256 -- pragma Import (C, K);
4257 -- begin
4258 -- K (A);
4259 -- end K;
4261 -- Now the contract applies in the normal way to the outer procedure,
4262 -- and the inner procedure has no contracts, so there is no problem
4263 -- in just calling it to get the original effect.
4265 -- In the case of a function, we create an appropriate return statement
4266 -- for the subprogram body that calls the inner procedure.
4278 begin
4279 -- Nothing to do if not imported
4284 -- Test enabling conditions for wrapping
4289 and then not GNATprove_Mode
4290 then
4291 -- Here we do the wrap
4293 -- Note on calls to Copy_Separate_Tree. The trees we are copying
4294 -- here are fully analyzed, but we definitely want fully syntactic
4295 -- unanalyzed trees in the body we construct, so that the analysis
4296 -- generates the right visibility, and that is exactly what the
4297 -- calls to Copy_Separate_Tree give us.
4299 -- Acquire copy of Inline pragma, and indicate that it does not
4300 -- come from an aspect, as it applies to an internal entity.
4305 -- Fix up spec to be not imported any more
4312 -- Grab the subprogram declaration and specification
4316 -- Build parameter list that we need
4325 -- Build the call
4328 Stmt :=
4330 Expression =>
4335 else
4336 Stmt :=
4342 -- Now build the body
4344 Bod :=
4346 Specification =>
4350 Specification =>
4352 Iprag),
4353 Handled_Statement_Sequence =>
4358 -- Append the body to freeze result
4363 -- Case of imported subprogram that does not get wrapped
4365 else
4366 -- Set Is_Public. All imported entities need an external symbol
4367 -- created for them since they are always referenced from another
4368 -- object file. Note this used to be set when we set Is_Imported
4369 -- back in Sem_Prag, but now we delay it to this point, since we
4370 -- don't want to set this flag if we wrap an imported subprogram.
4376 -- Start of processing for Freeze_Entity
4378 begin
4379 -- The entity being frozen may be subject to pragma Ghost with policy
4380 -- Ignore. Set the mode now to ensure that any nodes generated during
4381 -- freezing are properly flagged as ignored Ghost.
4385 -- We are going to test for various reasons why this entity need not be
4386 -- frozen here, but in the case of an Itype that's defined within a
4387 -- record, that test actually applies to the record.
4393 then
4397 -- Do not freeze if already frozen since we only need one freeze node
4400 Restore_Globals;
4403 -- It is improper to freeze an external entity within a generic because
4404 -- its freeze node will appear in a non-valid context. The entity will
4405 -- be frozen in the proper scope after the current generic is analyzed.
4406 -- However, aspects must be analyzed because they may be queried later
4407 -- within the generic itself, and the corresponding pragma or attribute
4408 -- definition has not been analyzed yet.
4415 Restore_Globals;
4418 -- AI05-0213: A formal incomplete type does not freeze the actual. In
4419 -- the instance, the same applies to the subtype renaming the actual.
4425 then
4426 Restore_Globals;
4429 -- Formal subprograms are never frozen
4432 Restore_Globals;
4435 -- Generic types are never frozen as they lack delayed semantic checks
4438 Restore_Globals;
4441 -- Do not freeze a global entity within an inner scope created during
4442 -- expansion. A call to subprogram E within some internal procedure
4443 -- (a stream attribute for example) might require freezing E, but the
4444 -- freeze node must appear in the same declarative part as E itself.
4445 -- The two-pass elaboration mechanism in gigi guarantees that E will
4446 -- be frozen before the inner call is elaborated. We exclude constants
4447 -- from this test, because deferred constants may be frozen early, and
4448 -- must be diagnosed (e.g. in the case of a deferred constant being used
4449 -- in a default expression). If the enclosing subprogram comes from
4450 -- source, or is a generic instance, then the freeze point is the one
4451 -- mandated by the language, and we freeze the entity. A subprogram that
4452 -- is a child unit body that acts as a spec does not have a spec that
4453 -- comes from source, but can only come from source.
4458 then
4459 declare
4462 begin
4469 then
4471 else
4472 Restore_Globals;
4481 -- Similarly, an inlined instance body may make reference to global
4482 -- entities, but these references cannot be the proper freezing point
4483 -- for them, and in the absence of inlining freezing will take place in
4484 -- their own scope. Normally instance bodies are analyzed after the
4485 -- enclosing compilation, and everything has been frozen at the proper
4486 -- place, but with front-end inlining an instance body is compiled
4487 -- before the end of the enclosing scope, and as a result out-of-order
4488 -- freezing must be prevented.
4490 elsif Front_End_Inlining
4491 and then In_Instance_Body
4493 then
4494 declare
4497 begin
4502 else
4508 Restore_Globals;
4516 Restore_Globals;
4520 -- Add checks to detect proper initialization of scalars that may appear
4521 -- as subprogram parameters.
4527 -- Deal with delayed aspect specifications. The analysis of the aspect
4528 -- is required to be delayed to the freeze point, thus we analyze the
4529 -- pragma or attribute definition clause in the tree at this point. We
4530 -- also analyze the aspect specification node at the freeze point when
4531 -- the aspect doesn't correspond to pragma/attribute definition clause.
4537 -- Here to freeze the entity
4541 -- Case of entity being frozen is other than a type
4545 -- If entity is exported or imported and does not have an external
4546 -- name, now is the time to provide the appropriate default name.
4547 -- Skip this if the entity is stubbed, since we don't need a name
4548 -- for any stubbed routine. For the case on intrinsics, if no
4549 -- external name is specified, then calls will be handled in
4550 -- Exp_Intr.Expand_Intrinsic_Call, and no name is needed. If an
4551 -- external name is provided, then Expand_Intrinsic_Call leaves
4552 -- calls in place for expansion by GIGI.
4558 then
4559 Set_Encoded_Interface_Name
4562 -- If entity is an atomic object appearing in a declaration and
4563 -- the expression is an aggregate, assign it to a temporary to
4564 -- ensure that the actual assignment is done atomically rather
4565 -- than component-wise (the assignment to the temp may be done
4566 -- component-wise, but that is harmless).
4573 then
4577 -- Subprogram case
4581 -- Check for needing to wrap imported subprogram
4585 -- Freeze all parameter types and the return type (RM 13.14(14)).
4586 -- However skip this for internal subprograms. This is also where
4587 -- any extra formal parameters are created since we now know
4588 -- whether the subprogram will use a foreign convention.
4590 -- In Ada 2012, freezing a subprogram does not always freeze
4591 -- the corresponding profile (see AI05-019). An attribute
4592 -- reference is not a freezing point of the profile.
4593 -- Other constructs that should not freeze ???
4595 -- This processing doesn't apply to internal entities (see below)
4599 Restore_Globals;
4604 -- Must freeze its parent first if it is a derived subprogram
4610 -- We don't freeze internal subprograms, because we don't normally
4611 -- want addition of extra formals or mechanism setting to happen
4612 -- for those. However we do pass through predefined dispatching
4613 -- cases, since extra formals may be needed in some cases, such as
4614 -- for the stream 'Input function (build-in-place formals).
4618 then
4624 Restore_Globals;
4628 -- If warning on suspicious contracts then check for the case of
4629 -- a postcondition other than False for a No_Return subprogram.
4632 and then Warn_On_Suspicious_Contract
4634 then
4635 declare
4639 begin
4642 Name_Postcondition,
4643 Name_Refined_Post)
4644 then
4645 Exp :=
4646 Expression
4651 then
4652 Error_Msg_NE
4663 -- Here for other than a subprogram or type
4665 else
4666 -- If entity has a type, and it is not a generic unit, then
4667 -- freeze it first (RM 13.14(10)).
4671 then
4674 -- For an object of an anonymous array type, aspects on the
4675 -- object declaration apply to the type itself. This is the
4676 -- case for Atomic_Components, Volatile_Components, and
4677 -- Independent_Components. In these cases analysis of the
4678 -- generated pragma will mark the anonymous types accordingly,
4679 -- and the object itself does not require a freeze node.
4685 then
4692 -- Special processing for objects created by object declaration
4696 -- Abstract type allowed only for C++ imported variables or
4697 -- constants.
4699 -- Note: we inhibit this check for objects that do not come
4700 -- from source because there is at least one case (the
4701 -- expansion of x'Class'Input where x is abstract) where we
4702 -- legitimately generate an abstract object.
4708 then
4713 Error_Msg_NE
4718 Error_Msg_N -- CODEFIX
4724 -- For object created by object declaration, perform required
4725 -- categorization (preelaborate and pure) checks. Defer these
4726 -- checks to freeze time since pragma Import inhibits default
4727 -- initialization and thus pragma Import affects these checks.
4731 -- If there is an address clause, check that it is valid
4735 -- Reset Is_True_Constant for non-constant aliased object. We
4736 -- consider that the fact that a non-constant object is aliased
4737 -- may indicate that some funny business is going on, e.g. an
4738 -- aliased object is passed by reference to a procedure which
4739 -- captures the address of the object, which is later used to
4740 -- assign a new value, even though the compiler thinks that
4741 -- it is not modified. Such code is highly dubious, but we
4742 -- choose to make it "work" for non-constant aliased objects.
4743 -- Note that we used to do this for all aliased objects,
4744 -- whether or not constant, but this caused anomalies down
4745 -- the line because we ended up with static objects that
4746 -- were not Is_True_Constant. Not resetting Is_True_Constant
4747 -- for (aliased) constant objects ensures that this anomaly
4748 -- never occurs.
4750 -- However, we don't do that for internal entities. We figure
4751 -- that if we deliberately set Is_True_Constant for an internal
4752 -- entity, e.g. a dispatch table entry, then we mean it.
4757 then
4761 -- If the object needs any kind of default initialization, an
4762 -- error must be issued if No_Default_Initialization applies.
4763 -- The check doesn't apply to imported objects, which are not
4764 -- ever default initialized, and is why the check is deferred
4765 -- until freezing, at which point we know if Import applies.
4766 -- Deferred constants are also exempted from this test because
4767 -- their completion is explicit, or through an import pragma.
4771 then
4777 and then
4782 or else
4785 then
4787 Check_Restriction
4791 -- Check that a Thread_Local_Storage variable does not have
4792 -- default initialization, and any explicit initialization must
4793 -- either be the null constant or a static constant.
4796 declare
4798 begin
4799 if Has_Default_Initialization
4800 or else
4802 and then
4804 or else not
4806 or else
4808 then
4809 Error_Msg_NE
4812 Error_Msg_NE
4819 -- For imported objects, set Is_Public unless there is also an
4820 -- address clause, which means that there is no external symbol
4821 -- needed for the Import (Is_Public may still be set for other
4822 -- unrelated reasons). Note that we delayed this processing
4823 -- till freeze time so that we can be sure not to set the flag
4824 -- if there is an address clause. If there is such a clause,
4825 -- then the only purpose of the Import pragma is to suppress
4826 -- implicit initialization.
4832 -- For source objects that are not Imported and are library
4833 -- level, if no linker section pragma was given inherit the
4834 -- appropriate linker section from the corresponding type.
4840 then
4841 Set_Linker_Section_Pragma
4845 -- For convention C objects of an enumeration type, warn if
4846 -- the size is not integer size and no explicit size given.
4847 -- Skip warning for Boolean, and Character, assume programmer
4848 -- expects 8-bit sizes for these cases.
4851 or else
4858 then
4860 Error_Msg_N
4862 E);
4867 -- Check that a constant which has a pragma Volatile[_Components]
4868 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
4870 -- Note: Atomic[_Components] also sets Volatile[_Components]
4876 then
4877 -- Make sure we actually have a pragma, and have not merely
4878 -- inherited the indication from elsewhere (e.g. an address
4879 -- clause, which is not good enough in RM terms).
4882 or else
4884 then
4885 Error_Msg_N
4890 or else
4892 then
4893 Error_Msg_N
4899 -- Static objects require special handling
4903 then
4907 -- Remaining step is to layout objects
4911 then
4915 -- For an object that does not have delayed freezing, and whose
4916 -- initialization actions have been captured in a compound
4917 -- statement, move them back now directly within the enclosing
4918 -- statement sequence.
4922 then
4927 -- Case of a type or subtype being frozen
4929 else
4930 -- We used to check here that a full type must have preelaborable
4931 -- initialization if it completes a private type specified with
4932 -- pragma Preelaborable_Initialization, but that missed cases where
4933 -- the types occur within a generic package, since the freezing
4934 -- that occurs within a containing scope generally skips traversal
4935 -- of a generic unit's declarations (those will be frozen within
4936 -- instances). This check was moved to Analyze_Package_Specification.
4938 -- The type may be defined in a generic unit. This can occur when
4939 -- freezing a generic function that returns the type (which is
4940 -- defined in a parent unit). It is clearly meaningless to freeze
4941 -- this type. However, if it is a subtype, its size may be determi-
4942 -- nable and used in subsequent checks, so might as well try to
4943 -- compute it.
4945 -- In Ada 2012, Freeze_Entities is also used in the front end to
4946 -- trigger the analysis of aspect expressions, so in this case we
4947 -- want to continue the freezing process.
4951 and then
4954 then
4956 Restore_Globals;
4960 -- Check for error of Type_Invariant'Class applied to an untagged
4961 -- type (check delayed to freeze time when full type is available).
4963 declare
4965 begin
4969 then
4970 Error_Msg_NE
4973 Error_Msg_N
4978 -- A Ghost type cannot be effectively volatile (SPARK RM 6.9(8))
4982 then
4986 -- Deal with special cases of freezing for subtype
4990 -- Before we do anything else, a specialized test for the case of
4991 -- a size given for an array where the array needs to be packed,
4992 -- but was not so the size cannot be honored. This is the case
4993 -- where implicit packing may apply. The reason we do this so
4994 -- early is that if we have implicit packing, the layout of the
4995 -- base type is affected, so we must do this before we freeze
4996 -- the base type.
4998 -- We could do this processing only if implicit packing is enabled
4999 -- since in all other cases, the error would be caught by the back
5000 -- end. However, we choose to do the check even if we do not have
5001 -- implicit packing enabled, since this allows us to give a more
5002 -- useful error message (advising use of pragmas Implicit_Packing
5003 -- or Pack).
5006 declare
5017 -- Number of elements in array
5019 begin
5020 -- Check enabling conditions. These are straightforward
5021 -- except for the test for a limited composite type. This
5022 -- eliminates the rare case of a array of limited components
5023 -- where there are issues of whether or not we can go ahead
5024 -- and pack the array (since we can't freely pack and unpack
5025 -- arrays if they are limited).
5027 -- Note that we check the root type explicitly because the
5028 -- whole point is we are doing this test before we have had
5029 -- a chance to freeze the base type (and it is that freeze
5030 -- action that causes stuff to be inherited).
5043 then
5044 -- Compute number of elements in array
5052 and then
5054 then
5058 Num_Elmts :=
5059 Num_Elmts *
5065 -- What we are looking for here is the situation where
5066 -- the RM_Size given would be exactly right if there was
5067 -- a pragma Pack (resulting in the component size being
5068 -- the same as the RM_Size). Furthermore, the component
5069 -- type size must be an odd size (not a multiple of
5070 -- storage unit). If the component RM size is an exact
5071 -- number of storage units that is a power of two, the
5072 -- array is not packed and has a standard representation.
5076 then
5077 -- For implicit packing mode, just set the component
5078 -- size silently.
5086 -- Otherwise give an error message
5088 else
5089 Error_Msg_NE
5091 Error_Msg_N -- CODEFIX
5097 and then Implicit_Packing
5098 and then
5100 or else
5102 or else
5104 then
5105 -- Not a packed array, but indicate the desired
5106 -- component size, for the back-end.
5116 -- If ancestor subtype present, freeze that first. Note that this
5117 -- will also get the base type frozen. Need RM reference ???
5124 -- No ancestor subtype present
5126 else
5127 -- See if we have a nearest ancestor that has a predicate.
5128 -- That catches the case of derived type with a predicate.
5129 -- Need RM reference here ???
5137 -- Freeze base type before freezing the entity (RM 13.14(15))
5144 -- A subtype inherits all the type-related representation aspects
5145 -- from its parents (RM 13.1(8)).
5149 -- For a derived type, freeze its parent type first (RM 13.14(15))
5155 -- A derived type inherits each type-related representation aspect
5156 -- of its parent type that was directly specified before the
5157 -- declaration of the derived type (RM 13.1(15)).
5162 -- Check for incompatible size and alignment for record type
5164 if Warn_On_Size_Alignment
5168 -- If explicit Object_Size clause given assume that the programmer
5169 -- knows what he is doing, and expects the compiler behavior.
5173 -- Check for size not a multiple of alignment
5176 then
5177 declare
5183 begin
5186 -- Give a warning
5190 Error_Msg_NE
5196 else
5198 Error_Msg_NE
5211 -- Array type
5216 -- For a class-wide type, the corresponding specific type is
5217 -- frozen as well (RM 13.14(15))
5222 -- If the base type of the class-wide type is still incomplete,
5223 -- the class-wide remains unfrozen as well. This is legal when
5224 -- E is the formal of a primitive operation of some other type
5225 -- which is being frozen.
5229 Restore_Globals;
5233 -- The equivalent type associated with a class-wide subtype needs
5234 -- to be frozen to ensure that its layout is done.
5238 then
5242 -- Generate an itype reference for a library-level class-wide type
5243 -- at the freeze point. Otherwise the first explicit reference to
5244 -- the type may appear in an inner scope which will be rejected by
5245 -- the back-end.
5249 then
5250 declare
5253 begin
5256 -- From a gigi point of view, a class-wide subtype derives
5257 -- from its record equivalent type. As a result, the itype
5258 -- reference must appear after the freeze node of the
5259 -- equivalent type or gigi will reject the reference.
5263 then
5265 else
5271 -- For a record type or record subtype, freeze all component types
5272 -- (RM 13.14(15)). We test for E_Record_(sub)Type here, rather than
5273 -- using Is_Record_Type, because we don't want to attempt the freeze
5274 -- for the case of a private type with record extension (we will do
5275 -- that later when the full type is frozen).
5280 then
5283 -- For a concurrent type, freeze corresponding record type. This does
5284 -- not correspond to any specific rule in the RM, but the record type
5285 -- is essentially part of the concurrent type. Also freeze all local
5286 -- entities. This includes record types created for entry parameter
5287 -- blocks and whatever local entities may appear in the private part.
5301 -- The guard on the presence of the Etype seems to be needed
5302 -- for some CodePeer (-gnatcC) cases, but not clear why???
5307 then
5318 -- Private types are required to point to the same freeze node as
5319 -- their corresponding full views. The freeze node itself has to
5320 -- point to the partial view of the entity (because from the partial
5321 -- view, we can retrieve the full view, but not the reverse).
5322 -- However, in order to freeze correctly, we need to freeze the full
5323 -- view. If we are freezing at the end of a scope (or within the
5324 -- scope) of the private type, the partial and full views will have
5325 -- been swapped, the full view appears first in the entity chain and
5326 -- the swapping mechanism ensures that the pointers are properly set
5327 -- (on scope exit).
5329 -- If we encounter the partial view before the full view (e.g. when
5330 -- freezing from another scope), we freeze the full view, and then
5331 -- set the pointers appropriately since we cannot rely on swapping to
5332 -- fix things up (subtypes in an outer scope might not get swapped).
5334 -- If the full view is itself private, the above requirements apply
5335 -- to the underlying full view instead of the full view. But there is
5336 -- no swapping mechanism for the underlying full view so we need to
5337 -- set the pointers appropriately in both cases.
5341 then
5342 -- The construction of the dispatch table associated with library
5343 -- level tagged types forces freezing of all the primitives of the
5344 -- type, which may cause premature freezing of the partial view.
5345 -- For example:
5347 -- package Pkg is
5348 -- type T is tagged private;
5349 -- type DT is new T with private;
5350 -- procedure Prim (X : in out T; Y : in out DT'Class);
5351 -- private
5352 -- type T is tagged null record;
5353 -- Obj : T;
5354 -- type DT is new T with null record;
5355 -- end;
5357 -- In this case the type will be frozen later by the usual
5358 -- mechanism: an object declaration, an instantiation, or the
5359 -- end of a declarative part.
5363 then
5365 Restore_Globals;
5368 -- Case of full view present
5372 -- If full view has already been frozen, then no further
5373 -- processing is required
5379 -- Otherwise freeze full view and patch the pointers so that
5380 -- the freeze node will elaborate both views in the back end.
5381 -- However, if full view is itself private, freeze underlying
5382 -- full view instead and patch the pointers so that the freeze
5383 -- node will elaborate the three views in the back end.
5385 else
5386 declare
5389 begin
5392 then
5400 then
5407 else
5420 else
5421 -- {Incomplete,Private}_Subtypes with Full_Views
5422 -- constrained by discriminants.
5433 -- AI-117 requires that the convention of a partial view be the
5434 -- same as the convention of the full view. Note that this is a
5435 -- recognized breach of privacy, but it's essential for logical
5436 -- consistency of representation, and the lack of a rule in
5437 -- RM95 was an oversight.
5444 -- Size information is copied from the full view to the
5445 -- incomplete or private view for consistency.
5447 -- We skip this is the full view is not a type. This is very
5448 -- strange of course, and can only happen as a result of
5449 -- certain illegalities, such as a premature attempt to derive
5450 -- from an incomplete type.
5457 Restore_Globals;
5460 -- Case of underlying full view present
5464 then
5469 -- Patch the pointers so that the freeze node will elaborate
5470 -- both views in the back end.
5479 else
5487 Restore_Globals;
5490 -- Case of no full view present. If entity is derived or subtype,
5491 -- it is safe to freeze, correctness depends on the frozen status
5492 -- of parent. Otherwise it is either premature usage, or a Taft
5493 -- amendment type, so diagnosis is at the point of use and the
5494 -- type might be frozen later.
5499 else
5501 Restore_Globals;
5505 -- For access subprogram, freeze types of all formals, the return
5506 -- type was already frozen, since it is the Etype of the function.
5507 -- Formal types can be tagged Taft amendment types, but otherwise
5508 -- they cannot be incomplete.
5516 then
5520 -- AI05-151: Incomplete types are allowed in access to
5521 -- subprogram specifications.
5524 Error_Msg_NE
5535 -- For access to a protected subprogram, freeze the equivalent type
5536 -- (however this is not set if we are not generating code or if this
5537 -- is an anonymous type used just for resolution).
5545 -- Generic types are never seen by the back-end, and are also not
5546 -- processed by the expander (since the expander is turned off for
5547 -- generic processing), so we never need freeze nodes for them.
5550 Restore_Globals;
5554 -- Some special processing for non-generic types to complete
5555 -- representation details not known till the freeze point.
5560 -- Some error checks required for ordinary fixed-point type. Defer
5561 -- these till the freeze-point since we need the small and range
5562 -- values. We only do these checks for base types
5567 Error_Msg_N
5572 Error_Msg_N
5578 Error_Msg_N
5584 Error_Msg_N
5596 and then Warn_On_Suspicious_Modulus_Value
5597 then
5601 -- The pool applies to named and anonymous access types, but not
5602 -- to subprogram and to internal types generated for 'Access
5603 -- references.
5608 then
5609 -- If a pragma Default_Storage_Pool applies, and this type has no
5610 -- Storage_Pool or Storage_Size clause (which must have occurred
5611 -- before the freezing point), then use the default. This applies
5612 -- only to base types.
5614 -- None of this applies to access to subprograms, for which there
5615 -- are clearly no pools.
5621 then
5622 -- Case of pragma Default_Storage_Pool (null)
5627 -- Case of pragma Default_Storage_Pool (storage_pool_NAME)
5629 else
5634 -- Check restriction for standard storage pool
5640 -- Deal with error message for pure access type. This is not an
5641 -- error in Ada 2005 if there is no pool (see AI-366).
5647 then
5651 Error_Msg_N
5655 Error_Msg_N
5658 else
5659 Error_Msg_N
5666 -- Case of composite types
5670 -- AI-117 requires that all new primitives of a tagged type must
5671 -- inherit the convention of the full view of the type. Inherited
5672 -- and overriding operations are defined to inherit the convention
5673 -- of their parent or overridden subprogram (also specified in
5674 -- AI-117), which will have occurred earlier (in Derive_Subprogram
5675 -- and New_Overloaded_Entity). Here we set the convention of
5676 -- primitives that are still convention Ada, which will ensure
5677 -- that any new primitives inherit the type's convention. Class-
5678 -- wide types can have a foreign convention inherited from their
5679 -- specific type, but are excluded from this since they don't have
5680 -- any associated primitives.
5685 then
5686 declare
5690 begin
5702 -- If the type is a simple storage pool type, then this is where
5703 -- we attempt to locate and validate its Allocate, Deallocate, and
5704 -- Storage_Size operations (the first is required, and the latter
5705 -- two are optional). We also verify that the full type for a
5706 -- private type is allowed to be a simple storage pool type.
5710 then
5711 -- If the type is marked Has_Private_Declaration, then this is
5712 -- a full type for a private type that was specified with the
5713 -- pragma Simple_Storage_Pool_Type, and here we ensure that the
5714 -- pragma is allowed for the full type (for example, it can't
5715 -- be an array type, or a nonlimited record type).
5720 then
5722 Error_Msg_N
5733 procedure Validate_Simple_Pool_Op_Formal
5740 -- Validate one formal Pool_Op_Formal of the candidate pool
5741 -- operation Pool_Op. The formal must be of Expected_Type
5742 -- and have mode Expected_Mode. OK_Formal will be set to
5743 -- False if the formal doesn't match. If OK_Formal is False
5744 -- on entry, then the formal will effectively be ignored
5745 -- (because validation of the pool op has already failed).
5746 -- Upon return, Pool_Op_Formal will be updated to the next
5747 -- formal, if any.
5749 procedure Validate_Simple_Pool_Operation
5751 -- Search for and validate a simple pool operation with the
5752 -- name Op_Name. If the name is Allocate, then there must be
5753 -- exactly one such primitive operation for the simple pool
5754 -- type. If the name is Deallocate or Storage_Size, then
5755 -- there can be at most one such primitive operation. The
5756 -- profile of the located primitive must conform to what
5757 -- is expected for each operation.
5759 ------------------------------------
5760 -- Validate_Simple_Pool_Op_Formal --
5761 ------------------------------------
5763 procedure Validate_Simple_Pool_Op_Formal
5770 is
5771 begin
5772 -- If OK_Formal is False on entry, then simply ignore
5773 -- the formal, because an earlier formal has already
5774 -- been flagged.
5779 -- If no formal is passed in, then issue an error for a
5780 -- missing formal.
5783 Error_Msg_NE
5793 -- If the pool type was expected for this formal, then
5794 -- this will not be considered a candidate operation
5795 -- for the simple pool, so we unset OK_Formal so that
5796 -- the op and any later formals will be ignored.
5803 else
5804 Error_Msg_NE
5811 -- Issue error if formal's mode is not the expected one
5814 Error_Msg_N
5816 Pool_Op_Formal);
5819 -- Advance to the next formal
5824 ------------------------------------
5825 -- Validate_Simple_Pool_Operation --
5826 ------------------------------------
5828 procedure Validate_Simple_Pool_Operation
5830 is
5836 begin
5837 pragma Assert
5839 Name_Deallocate,
5840 Name_Storage_Size));
5844 -- For each homonym declared immediately in the scope
5845 -- of the simple storage pool type, determine whether
5846 -- the homonym is an operation of the pool type, and,
5847 -- if so, check that its profile is as expected for
5848 -- a simple pool operation of that name.
5854 then
5859 -- The first parameter must be of the pool type
5860 -- in order for the operation to qualify.
5863 Validate_Simple_Pool_Op_Formal
5866 else
5867 Validate_Simple_Pool_Op_Formal
5872 -- If another operation with this name has already
5873 -- been located for the type, then flag an error,
5874 -- since we only allow the type to have a single
5875 -- such primitive.
5878 Error_Msg_NE
5883 -- In the case of Allocate and Deallocate, a formal
5884 -- of type System.Address is required.
5887 Validate_Simple_Pool_Op_Formal
5892 Validate_Simple_Pool_Op_Formal
5897 -- In the case of Allocate and Deallocate, formals
5898 -- of type Storage_Count are required as the third
5899 -- and fourth parameters.
5902 Validate_Simple_Pool_Op_Formal
5905 Validate_Simple_Pool_Op_Formal
5910 -- If no mismatched formals have been found (Is_OK)
5911 -- and no excess formals are present, then this
5912 -- operation has been validated, so record it.
5922 -- There must be a valid Allocate operation for the type,
5923 -- so issue an error if none was found.
5927 then
5933 -- Simple pool operations can't be abstract
5936 Error_Msg_N
5941 -- The Storage_Size operation must be a function with
5942 -- Storage_Count as its result type.
5946 Error_Msg_N
5950 Error_Msg_NE
5955 -- Allocate and Deallocate must be procedures
5958 Error_Msg_N
5964 -- Start of processing for Validate_Simple_Pool_Ops
5966 begin
5974 -- Now that all types from which E may depend are frozen, see if the
5975 -- size is known at compile time, if it must be unsigned, or if
5976 -- strict alignment is required
5985 -- Do not allow a size clause for a type which does not have a size
5986 -- that is known at compile time
5990 then
5991 -- Suppress this message if errors posted on E, even if we are
5992 -- in all errors mode, since this is often a junk message
5995 Error_Msg_N
6001 -- Now we set/verify the representation information, in particular
6002 -- the size and alignment values. This processing is not required for
6003 -- generic types, since generic types do not play any part in code
6004 -- generation, and so the size and alignment values for such types
6005 -- are irrelevant. Ditto for types declared within a generic unit,
6006 -- which may have components that depend on generic parameters, and
6007 -- that will be recreated in an instance.
6012 -- Otherwise we call the layout procedure
6014 else
6018 -- If this is an access to subprogram whose designated type is itself
6019 -- a subprogram type, the return type of this anonymous subprogram
6020 -- type must be decorated as well.
6024 then
6028 -- If the type has a Defaut_Value/Default_Component_Value aspect,
6029 -- this is where we analye the expression (after the type is frozen,
6030 -- since in the case of Default_Value, we are analyzing with the
6031 -- type itself, and we treat Default_Component_Value similarly for
6032 -- the sake of uniformity).
6035 declare
6040 begin
6045 else
6056 Flag_Non_Static_Expr
6063 -- End of freeze processing for type entities
6066 -- Here is where we logically freeze the current entity. If it has a
6067 -- freeze node, then this is the point at which the freeze node is
6068 -- linked into the result list.
6072 -- If a freeze node is already allocated, use it, otherwise allocate
6073 -- a new one. The preallocation happens in the case of anonymous base
6074 -- types, where we preallocate so that we can set First_Subtype_Link.
6075 -- Note that we reset the Sloc to the current freeze location.
6081 else
6092 -- A final pass over record types with discriminants. If the type
6093 -- has an incomplete declaration, there may be constrained access
6094 -- subtypes declared elsewhere, which do not depend on the discrimi-
6095 -- nants of the type, and which are used as component types (i.e.
6096 -- the full view is a recursive type). The designated types of these
6097 -- subtypes can only be elaborated after the type itself, and they
6098 -- need an itype reference.
6102 then
6103 declare
6108 begin
6118 then
6130 -- When a type is frozen, the first subtype of the type is frozen as
6131 -- well (RM 13.14(15)). This has to be done after freezing the type,
6132 -- since obviously the first subtype depends on its own base type.
6137 -- If we just froze a tagged non-class wide record, then freeze the
6138 -- corresponding class-wide type. This must be done after the tagged
6139 -- type itself is frozen, because the class-wide type refers to the
6140 -- tagged type which generates the class.
6145 then
6152 -- Special handling for subprograms
6156 -- If subprogram has address clause then reset Is_Public flag, since
6157 -- we do not want the backend to generate external references.
6161 then
6166 Restore_Globals;
6170 -----------------------------
6171 -- Freeze_Enumeration_Type --
6172 -----------------------------
6175 begin
6176 -- By default, if no size clause is present, an enumeration type with
6177 -- Convention C is assumed to interface to a C enum, and has integer
6178 -- size. This applies to types. For subtypes, verify that its base
6179 -- type has no size clause either. Treat other foreign conventions
6180 -- in the same way, and also make sure alignment is set right.
6187 -- Don't do this if Short_Enums on target
6189 and then not Target_Short_Enums
6190 then
6194 -- Normal Ada case or size clause present or not Long_C_Enums on target
6196 else
6197 -- If the enumeration type interfaces to C, and it has a size clause
6198 -- that specifies less than int size, it warrants a warning. The
6199 -- user may intend the C type to be an enum or a char, so this is
6200 -- not by itself an error that the Ada compiler can detect, but it
6201 -- it is a worth a heads-up. For Boolean and Character types we
6202 -- assume that the programmer has the proper C type in mind.
6210 -- Don't do this if Short_Enums on target
6212 and then not Target_Short_Enums
6213 then
6214 Error_Msg_N
6222 -----------------------
6223 -- Freeze_Expression --
6224 -----------------------
6235 -- This flag is set true if the entity must be frozen outside the
6236 -- current subprogram. This happens in the case of expander generated
6237 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
6238 -- not freeze all entities like other bodies, but which nevertheless
6239 -- may reference entities that have to be frozen before the body and
6240 -- obviously cannot be frozen inside the body.
6243 -- If the expression is an array aggregate, the type of the component
6244 -- expressions is also frozen. If the component type is an access type
6245 -- and the expressions include allocators, the designed type is frozen
6246 -- as well.
6249 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
6250 -- it is the handled statement sequence of an expander-generated
6251 -- subprogram (init proc, stream subprogram, or renaming as body).
6252 -- If so, this is not a freezing context.
6254 -----------------------------------------
6255 -- Find_Aggregate_Component_Desig_Type --
6256 -----------------------------------------
6262 begin
6288 ----------------------
6289 -- In_Expanded_Body --
6290 ----------------------
6296 begin
6299 else
6306 else
6309 -- The following are expander-created bodies, or bodies that
6310 -- are not freeze points.
6319 N_Subprogram_Renaming_Declaration,
6320 N_Expression_Function))
6321 then
6323 else
6329 -- Start of processing for Freeze_Expression
6331 begin
6332 -- Immediate return if freezing is inhibited. This flag is set by the
6333 -- analyzer to stop freezing on generated expressions that would cause
6334 -- freezing if they were in the source program, but which are not
6335 -- supposed to freeze, since they are created.
6341 -- If expression is non-static, then it does not freeze in a default
6342 -- expression, see section "Handling of Default Expressions" in the
6343 -- spec of package Sem for further details. Note that we have to make
6344 -- sure that we actually have a real expression (if we have a subtype
6345 -- indication, we can't test Is_OK_Static_Expression). However, we
6346 -- exclude the case of the prefix of an attribute of a static scalar
6347 -- subtype from this early return, because static subtype attributes
6348 -- should always cause freezing, even in default expressions, but
6349 -- the attribute may not have been marked as static yet (because in
6350 -- Resolve_Attribute, the call to Eval_Attribute follows the call of
6351 -- Freeze_Expression on the prefix).
6353 if In_Spec_Exp
6360 then
6364 -- Freeze type of expression if not frozen already
6372 -- Base type may be an derived numeric type that is frozen at
6373 -- the point of declaration, but first_subtype is still unfrozen.
6380 -- For entity name, freeze entity if not frozen already. A special
6381 -- exception occurs for an identifier that did not come from source.
6382 -- We don't let such identifiers freeze a non-internal entity, i.e.
6383 -- an entity that did come from source, since such an identifier was
6384 -- generated by the expander, and cannot have any semantic effect on
6385 -- the freezing semantics. For example, this stops the parameter of
6386 -- an initialization procedure from freezing the variable.
6393 then
6400 else
6404 -- For an allocator freeze designated type if not frozen already
6406 -- For an aggregate whose component type is an access type, freeze the
6407 -- designated type now, so that its freeze does not appear within the
6408 -- loop that might be created in the expansion of the aggregate. If the
6409 -- designated type is a private type without full view, the expression
6410 -- cannot contain an allocator, so the type is not frozen.
6412 -- For a function, we freeze the entity when the subprogram declaration
6413 -- is frozen, but a function call may appear in an initialization proc.
6414 -- before the declaration is frozen. We need to generate the extra
6415 -- formals, if any, to ensure that the expansion of the call includes
6416 -- the proper actuals. This only applies to Ada subprograms, not to
6417 -- imported ones.
6428 then
6430 -- Check whether aggregate includes allocators.
6435 when N_Selected_Component |
6436 N_Indexed_Component |
6437 N_Slice =>
6448 then
6459 then
6463 -- All done if nothing needs freezing
6468 then
6472 -- Examine the enclosing context by climbing the parent chain. The
6473 -- traversal serves two purposes - to detect scenarios where freezeing
6474 -- is not needed and to find the proper insertion point for the freeze
6475 -- nodes. Although somewhat similar to Insert_Actions, this traversal
6476 -- is freezing semantics-sensitive. Inserting freeze nodes blindly in
6477 -- the tree may result in types being frozen too early.
6480 loop
6483 -- If we don't have a parent, then we are not in a well-formed tree.
6484 -- This is an unusual case, but there are some legitimate situations
6485 -- in which this occurs, notably when the expressions in the range of
6486 -- a type declaration are resolved. We simply ignore the freeze
6487 -- request in this case. Is this right ???
6493 -- See if we have got to an appropriate point in the tree
6497 -- A special test for the exception of (RM 13.14(8)) for the case
6498 -- of per-object expressions (RM 3.8(18)) occurring in component
6499 -- definition or a discrete subtype definition. Note that we test
6500 -- for a component declaration which includes both cases we are
6501 -- interested in, and furthermore the tree does not have explicit
6502 -- nodes for either of these two constructs.
6506 -- The case we want to test for here is an identifier that is
6507 -- a per-object expression, this is either a discriminant that
6508 -- appears in a context other than the component declaration
6509 -- or it is a reference to the type of the enclosing construct.
6511 -- For either of these cases, we skip the freezing
6513 if not In_Spec_Expression
6516 then
6517 -- We recognize the discriminant case by just looking for
6518 -- a reference to a discriminant. It can only be one for
6519 -- the enclosing construct. Skip freezing in this case.
6524 -- For the case of a reference to the enclosing record,
6525 -- (or task or protected type), we look for a type that
6526 -- matches the current scope.
6533 -- If we have an enumeration literal that appears as the choice in
6534 -- the aggregate of an enumeration representation clause, then
6535 -- freezing does not occur (RM 13.14(10)).
6539 -- The case we are looking for is an enumeration literal
6543 then
6544 -- If enumeration literal appears directly as the choice,
6545 -- do not freeze (this is the normal non-overloaded case)
6549 then
6552 -- If enumeration literal appears as the name of function
6553 -- which is the choice, then also do not freeze. This
6554 -- happens in the overloaded literal case, where the
6555 -- enumeration literal is temporarily changed to a function
6556 -- call for overloading analysis purposes.
6559 and then
6561 and then
6563 then
6568 -- Normally if the parent is a handled sequence of statements,
6569 -- then the current node must be a statement, and that is an
6570 -- appropriate place to insert a freeze node.
6574 -- An exception occurs when the sequence of statements is for
6575 -- an expander generated body that did not do the usual freeze
6576 -- all operation. In this case we usually want to freeze
6577 -- outside this body, not inside it, and we skip past the
6578 -- subprogram body that we are inside.
6581 declare
6585 begin
6586 -- Freeze the entity only when it is declared inside the
6587 -- body of the expander generated procedure. This case
6588 -- is recognized by the scope of the entity or its type,
6589 -- which is either the spec for some enclosing body, or
6590 -- (in the case of init_procs, for which there are no
6591 -- separate specs) the current scope.
6597 or else
6599 then
6605 then
6610 -- An expression function may act as a completion of
6611 -- a function declaration. As such, it can reference
6612 -- entities declared between the two views:
6614 -- Hidden []; -- 1
6615 -- function F return ...;
6616 -- private
6617 -- function Hidden return ...;
6618 -- function F return ... is (Hidden); -- 2
6620 -- Refering to the example above, freezing the expression
6621 -- of F (2) would place Hidden's freeze node (1) in the
6622 -- wrong place. Avoid explicit freezing and let the usual
6623 -- scenarios do the job - for example, reaching the end
6624 -- of the private declarations, or a call to F.
6627 N_Expression_Function
6628 then
6631 -- Freeze outside the body
6633 else
6639 -- Here if normal case where we are in handled statement
6640 -- sequence and want to do the insertion right there.
6642 else
6646 -- If parent is a body or a spec or a block, then the current node
6647 -- is a statement or declaration and we can insert the freeze node
6648 -- before it.
6650 when N_Block_Statement |
6651 N_Entry_Body |
6652 N_Package_Body |
6653 N_Package_Specification |
6654 N_Protected_Body |
6655 N_Subprogram_Body |
6658 -- The expander is allowed to define types in any statements list,
6659 -- so any of the following parent nodes also mark a freezing point
6660 -- if the actual node is in a list of statements or declarations.
6662 when N_Abortable_Part |
6663 N_Accept_Alternative |
6664 N_And_Then |
6665 N_Case_Statement_Alternative |
6666 N_Compilation_Unit_Aux |
6667 N_Conditional_Entry_Call |
6668 N_Delay_Alternative |
6669 N_Elsif_Part |
6670 N_Entry_Call_Alternative |
6671 N_Exception_Handler |
6672 N_Extended_Return_Statement |
6673 N_Freeze_Entity |
6674 N_If_Statement |
6675 N_Or_Else |
6676 N_Selective_Accept |
6677 N_Triggering_Alternative =>
6681 -- Freeze nodes produced by an expression coming from the Actions
6682 -- list of a N_Expression_With_Actions node must remain within the
6683 -- Actions list. Inserting the freeze nodes further up the tree
6684 -- may lead to use before declaration issues in the case of array
6685 -- types.
6690 then
6694 -- Note: N_Loop_Statement is a special case. A type that appears
6695 -- in the source can never be frozen in a loop (this occurs only
6696 -- because of a loop expanded by the expander), so we keep on
6697 -- going. Otherwise we terminate the search. Same is true of any
6698 -- entity which comes from source. (if they have predefined type,
6699 -- that type does not appear to come from source, but the entity
6700 -- should not be frozen here).
6706 -- For all other cases, keep looking at parents
6712 -- We fall through the case if we did not yet find the proper
6713 -- place in the free for inserting the freeze node, so climb.
6718 -- If the expression appears in a record or an initialization procedure,
6719 -- the freeze nodes are collected and attached to the current scope, to
6720 -- be inserted and analyzed on exit from the scope, to insure that
6721 -- generated entities appear in the correct scope. If the expression is
6722 -- a default for a discriminant specification, the scope is still void.
6723 -- The expression can also appear in the discriminant part of a private
6724 -- or concurrent type.
6726 -- If the expression appears in a constrained subcomponent of an
6727 -- enclosing record declaration, the freeze nodes must be attached to
6728 -- the outer record type so they can eventually be placed in the
6729 -- enclosing declaration list.
6731 -- The other case requiring this special handling is if we are in a
6732 -- default expression, since in that case we are about to freeze a
6733 -- static type, and the freeze scope needs to be the outer scope, not
6734 -- the scope of the subprogram with the default parameter.
6736 -- For default expressions and other spec expressions in generic units,
6737 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
6738 -- placing them at the proper place, after the generic unit.
6741 or else Freeze_Outside
6746 then
6747 declare
6752 begin
6765 -- The current scope may be that of a constrained component of
6766 -- an enclosing record declaration, or of a loop of an enclosing
6767 -- quantified expression, which is above the current scope in the
6768 -- scope stack. Indeed in the context of a quantified expression,
6769 -- a scope is created and pushed above the current scope in order
6770 -- to emulate the loop-like behavior of the quantified expression.
6771 -- If the expression is within a top-level pragma, as for a pre-
6772 -- condition on a library-level subprogram, nothing to do.
6777 N_Quantified_Expression)
6778 then
6785 Freeze_Nodes;
6786 else
6796 -- Now we have the right place to do the freezing. First, a special
6797 -- adjustment, if we are in spec-expression analysis mode, these freeze
6798 -- actions must not be thrown away (normally all inserted actions are
6799 -- thrown away in this mode. However, the freeze actions are from static
6800 -- expressions and one of the important reasons we are doing this
6801 -- special analysis is to get these freeze actions. Therefore we turn
6802 -- off the In_Spec_Expression mode to propagate these freeze actions.
6803 -- This also means they get properly analyzed and expanded.
6807 -- Freeze the designated type of an allocator (RM 13.14(13))
6813 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
6814 -- the enumeration representation clause exception in the loop above.
6820 -- Freeze name if one is present (RM 13.14(11))
6826 -- Restore In_Spec_Expression flag
6831 -----------------------------
6832 -- Freeze_Fixed_Point_Type --
6833 -----------------------------
6835 -- Certain fixed-point types and subtypes, including implicit base types
6836 -- and declared first subtypes, have not yet set up a range. This is
6837 -- because the range cannot be set until the Small and Size values are
6838 -- known, and these are not known till the type is frozen.
6840 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
6841 -- whose bounds are unanalyzed real literals. This routine will recognize
6842 -- this case, and transform this range node into a properly typed range
6843 -- with properly analyzed and resolved values.
6860 -- Save original bounds (for shaving tests)
6863 -- Actual size chosen
6866 -- Returns size of type with given bounds. Also leaves these
6867 -- bounds set as the current bounds of the Typ.
6869 -----------
6870 -- Fsize --
6871 -----------
6874 begin
6880 -- Start of processing for Freeze_Fixed_Point_Type
6882 begin
6883 -- If Esize of a subtype has not previously been set, set it now
6890 else
6895 -- Immediate return if the range is already analyzed. This means that
6896 -- the range is already set, and does not need to be computed by this
6897 -- routine.
6903 -- Immediate return if either of the bounds raises Constraint_Error
6907 then
6917 -- Ordinary fixed-point case
6921 -- For the ordinary fixed-point case, we are allowed to fudge the
6922 -- end-points up or down by small. Generally we prefer to fudge up,
6923 -- i.e. widen the bounds for non-model numbers so that the end points
6924 -- are included. However there are cases in which this cannot be
6925 -- done, and indeed cases in which we may need to narrow the bounds.
6926 -- The following circuit makes the decision.
6928 -- Note: our terminology here is that Incl_EP means that the bounds
6929 -- are widened by Small if necessary to include the end points, and
6930 -- Excl_EP means that the bounds are narrowed by Small to exclude the
6931 -- end-points if this reduces the size.
6933 -- Note that in the Incl case, all we care about is including the
6934 -- end-points. In the Excl case, we want to narrow the bounds as
6935 -- much as permitted by the RM, to give the smallest possible size.
6952 begin
6953 -- First step. Base types are required to be symmetrical. Right
6954 -- now, the base type range is a copy of the first subtype range.
6955 -- This will be corrected before we are done, but right away we
6956 -- need to deal with the case where both bounds are non-negative.
6957 -- In this case, we set the low bound to the negative of the high
6958 -- bound, to make sure that the size is computed to include the
6959 -- required sign. Note that we do not need to worry about the
6960 -- case of both bounds negative, because the sign will be dealt
6961 -- with anyway. Furthermore we can't just go making such a bound
6962 -- symmetrical, since in a twos-complement system, there is an
6963 -- extra negative value which could not be accommodated on the
6964 -- positive side.
6969 then
6974 -- Compute the fudged bounds. If the number is a model number,
6975 -- then we do nothing to include it, but we are allowed to backoff
6976 -- to the next adjacent model number when we exclude it. If it is
6977 -- not a model number then we straddle the two values with the
6978 -- model numbers on either side.
6984 else
6988 -- The low value excluding the end point is Small greater, but
6989 -- we do not do this exclusion if the low value is positive,
6990 -- since it can't help the size and could actually hurt by
6991 -- crossing the high bound.
6996 -- If the value went from negative to zero, then we have the
6997 -- case where Loval_Incl_EP is the model number just below
6998 -- zero, so we want to stick to the negative value for the
6999 -- base type to maintain the condition that the size will
7000 -- include signed values.
7004 then
7008 else
7012 -- Similar processing for upper bound and high value
7018 else
7024 else
7028 -- One further adjustment is needed. In the case of subtypes, we
7029 -- cannot go outside the range of the base type, or we get
7030 -- peculiarities, and the base type range is already set. This
7031 -- only applies to the Incl values, since clearly the Excl values
7032 -- are already as restricted as they are allowed to be.
7039 -- Get size including and excluding end points
7044 -- No need to exclude end-points if it does not reduce size
7054 -- Now we set the actual size to be used. We want to use the
7055 -- bounds fudged up to include the end-points but only if this
7056 -- can be done without violating a specifically given size
7057 -- size clause or causing an unacceptable increase in size.
7059 -- Case of size clause given
7063 -- Use the inclusive size only if it is consistent with
7064 -- the explicitly specified size.
7071 -- If the inclusive size is too large, we try excluding
7072 -- the end-points (will be caught later if does not work).
7074 else
7080 -- Case of size clause not given
7082 else
7083 -- If we have a base type whose corresponding first subtype
7084 -- has an explicit size that is large enough to include our
7085 -- end-points, then do so. There is no point in working hard
7086 -- to get a base type whose size is smaller than the specified
7087 -- size of the first subtype.
7093 then
7098 -- If excluding the end-points makes the size smaller and
7099 -- results in a size of 8,16,32,64, then we take the smaller
7100 -- size. For the 64 case, this is compulsory. For the other
7101 -- cases, it seems reasonable. We like to include end points
7102 -- if we can, but not at the expense of moving to the next
7103 -- natural boundary of size.
7107 then
7112 -- Otherwise we can definitely include the end points
7114 else
7120 -- One pathological case: normally we never fudge a low bound
7121 -- down, since it would seem to increase the size (if it has
7122 -- any effect), but for ranges containing single value, or no
7123 -- values, the high bound can be small too large. Consider:
7125 -- type t is delta 2.0**(-14)
7126 -- range 131072.0 .. 0;
7128 -- That lower bound is *just* outside the range of 32 bits, and
7129 -- does need fudging down in this case. Note that the bounds
7130 -- will always have crossed here, since the high bound will be
7131 -- fudged down if necessary, as in the case of:
7133 -- type t is delta 2.0**(-14)
7134 -- range 131072.0 .. 131072.0;
7136 -- So we detect the situation by looking for crossed bounds,
7137 -- and if the bounds are crossed, and the low bound is greater
7138 -- than zero, we will always back it off by small, since this
7139 -- is completely harmless.
7146 -- And of course, we need to do exactly the same parallel
7147 -- fudge for flat ranges in the negative region.
7160 -- For the decimal case, none of this fudging is required, since there
7161 -- are no end-point problems in the decimal case (the end-points are
7162 -- always included).
7164 else
7168 -- At this stage, the actual size has been calculated and the proper
7169 -- required bounds are stored in the low and high bounds.
7173 Error_Msg_N
7175 Typ);
7179 -- Check size against explicit given size
7185 Error_Msg_NE
7189 else
7193 -- Increase size to next natural boundary if no size clause given
7195 else
7202 else
7210 -- If we have a base type, then expand the bounds so that they extend to
7211 -- the full width of the allocated size in bits, to avoid junk range
7212 -- checks on intermediate computations.
7219 -- Final step is to reanalyze the bounds using the proper type
7220 -- and set the Corresponding_Integer_Value fields of the literals.
7226 -- Resolve with universal fixed if the base type, and the base type if
7227 -- it is a subtype. Note we can't resolve the base type with itself,
7228 -- that would be a reference before definition.
7232 else
7236 -- Set corresponding integer value for bound
7238 Set_Corresponding_Integer_Value
7241 -- Similar processing for high bound
7249 else
7253 Set_Corresponding_Integer_Value
7256 -- Set type of range to correspond to bounds
7260 -- Set Esize to calculated size if not set already
7266 -- Set RM_Size if not already set. If already set, check value
7268 declare
7271 begin
7276 Error_Msg_NE
7281 else
7286 -- Check for shaving
7290 Error_Msg_N
7292 Error_Msg_N
7297 Error_Msg_N
7299 Error_Msg_N
7305 ------------------
7306 -- Freeze_Itype --
7307 ------------------
7312 begin
7321 --------------------------
7322 -- Freeze_Static_Object --
7323 --------------------------
7328 -- Exception raised if the type of a static object cannot be made
7329 -- static. This happens if the type depends on non-global objects.
7332 -- Called to ensure that an expression used as part of a type definition
7333 -- is statically allocatable, which means that the expression type is
7334 -- statically allocatable, and the expression is either static, or a
7335 -- reference to a library level constant.
7338 -- Called to mark a type as static, checking that it is possible
7339 -- to set the type as static. If it is not possible, then the
7340 -- exception Cannot_Be_Static is raised.
7342 -----------------------------
7343 -- Ensure_Expression_Is_SA --
7344 -----------------------------
7349 begin
7361 then
7369 -----------------------
7370 -- Ensure_Type_Is_SA --
7371 -----------------------
7377 begin
7378 -- If type is library level, we are all set
7384 -- We are also OK if the type already marked as statically allocated,
7385 -- which means we processed it before.
7391 -- Mark type as statically allocated
7395 -- Check that it is safe to statically allocate this type
7413 declare
7417 begin
7429 else
7438 then
7457 else
7462 -- Start of processing for Freeze_Static_Object
7464 begin
7467 exception
7470 -- If the object that cannot be static is imported or exported, then
7471 -- issue an error message saying that this object cannot be imported
7472 -- or exported. If it has an address clause it is an overlay in the
7473 -- current partition and the static requirement is not relevant.
7474 -- Do not issue any error message when ignoring rep clauses.
7481 Error_Msg_N
7485 -- Otherwise must be exported, something is wrong if compiler
7486 -- is marking something as statically allocated which cannot be).
7489 Error_Msg_N
7494 -----------------------
7495 -- Freeze_Subprogram --
7496 -----------------------
7502 begin
7503 -- Subprogram may not have an address clause unless it is imported
7507 Error_Msg_N
7514 -- Reset the Pure indication on an imported subprogram unless an
7515 -- explicit Pure_Function pragma was present or the subprogram is an
7516 -- intrinsic. We do this because otherwise it is an insidious error
7517 -- to call a non-pure function from pure unit and have calls
7518 -- mysteriously optimized away. What happens here is that the Import
7519 -- can bypass the normal check to ensure that pure units call only pure
7520 -- subprograms.
7522 -- The reason for the intrinsic exception is that in general, intrinsic
7523 -- functions (such as shifts) are pure anyway. The only exceptions are
7524 -- the intrinsics in GNAT.Source_Info, and that unit is not marked Pure
7525 -- in any case, so no problem arises.
7531 then
7535 -- For non-foreign convention subprograms, this is where we create
7536 -- the extra formals (for accessibility level and constrained bit
7537 -- information). We delay this till the freeze point precisely so
7538 -- that we know the convention.
7544 -- If this is convention Ada and a Valued_Procedure, that's odd
7549 and then Warn_On_Export_Import
7550 then
7551 Error_Msg_N
7556 -- Case of foreign convention
7558 else
7561 -- For foreign conventions, warn about return of unconstrained array
7566 -- If no return type, probably some other error, e.g. a
7567 -- missing full declaration, so ignore.
7572 -- If the return type is generic, we have emitted a warning
7573 -- earlier on, and there is nothing else to check here. Specific
7574 -- instantiations may lead to erroneous behavior.
7579 -- Display warning if returning unconstrained array
7584 -- Check appropriate warning is enabled (should we check for
7585 -- Warnings (Off) on specific entities here, probably so???)
7587 and then Warn_On_Export_Import
7589 -- Exclude the VM case, since return of unconstrained arrays
7590 -- is properly handled in both the JVM and .NET cases.
7593 then
7594 Error_Msg_N
7601 -- If any of the formals for an exported foreign convention
7602 -- subprogram have defaults, then emit an appropriate warning since
7603 -- this is odd (default cannot be used from non-Ada code)
7608 if Warn_On_Export_Import
7610 then
7611 Error_Msg_N
7621 -- Pragma Inline_Always is disallowed for dispatching subprograms
7622 -- because the address of such subprograms is saved in the dispatch
7623 -- table to support dispatching calls, and dispatching calls cannot
7624 -- be inlined. This is consistent with the restriction against using
7625 -- 'Access or 'Address on an Inline_Always subprogram.
7629 then
7630 Error_Msg_N
7634 -- Because of the implicit representation of inherited predefined
7635 -- operators in the front-end, the overriding status of the operation
7636 -- may be affected when a full view of a type is analyzed, and this is
7637 -- not captured by the analysis of the corresponding type declaration.
7638 -- Therefore the correctness of a not-overriding indicator must be
7639 -- rechecked when the subprogram is frozen.
7643 then
7648 ----------------------
7649 -- Is_Fully_Defined --
7650 ----------------------
7653 begin
7662 then
7663 -- Verify that the record type has no components with private types
7664 -- without completion.
7666 declare
7669 begin
7681 -- For the designated type of an access to subprogram, all types in
7682 -- the profile must be fully defined.
7685 declare
7688 begin
7701 else
7707 ---------------------------------
7708 -- Process_Default_Expressions --
7709 ---------------------------------
7711 procedure Process_Default_Expressions
7714 is
7721 begin
7724 -- A subprogram instance and its associated anonymous subprogram share
7725 -- their signature. The default expression functions are defined in the
7726 -- wrapper packages for the anonymous subprogram, and should not be
7727 -- generated again for the instance.
7732 then
7740 -- We work with a copy of the default expression because we
7741 -- do not want to disturb the original, since this would mess
7742 -- up the conformance checking.
7746 -- The analysis of the expression may generate insert actions,
7747 -- which of course must not be executed. We wrap those actions
7748 -- in a procedure that is not called, and later on eliminated.
7749 -- The following cases have no side-effects, and are analyzed
7750 -- directly.
7754 N_Integer_Literal,
7755 N_Character_Literal,
7756 N_String_Literal,
7757 N_Real_Literal)
7761 then
7762 -- If there is no default function, we must still do a full
7763 -- analyze call on the default value, to ensure that all error
7764 -- checks are performed, e.g. those associated with static
7765 -- evaluation. Note: this branch will always be taken if the
7766 -- analyzer is turned off (but we still need the error checks).
7768 -- Note: the setting of parent here is to meet the requirement
7769 -- that we can only analyze the expression while attached to
7770 -- the tree. Really the requirement is that the parent chain
7771 -- be set, we don't actually need to be in the tree.
7776 -- Default expressions are resolved with their own type if the
7777 -- context is generic, to avoid anomalies with private types.
7781 else
7785 -- If that resolved expression will raise constraint error,
7786 -- then flag the default value as raising constraint error.
7787 -- This allows a proper error message on the calls.
7793 -- If the default is a parameterless call, we use the name of
7794 -- the called function directly, and there is no body to build.
7798 then
7801 -- Else construct and analyze the body of a wrapper procedure
7802 -- that contains an object declaration to hold the expression.
7803 -- Given that this is done only to complete the analysis, it
7804 -- simpler to build a procedure than a function which might
7805 -- involve secondary stack expansion.
7807 else
7810 Dbody :=
7812 Specification =>
7819 Object_Definition =>
7823 Handled_Statement_Sequence =>
7840 ----------------------------------------
7841 -- Set_Component_Alignment_If_Not_Set --
7842 ----------------------------------------
7845 begin
7846 -- Ignore if not base type, subtypes don't need anything
7852 -- Do not override existing representation
7863 else
7864 Set_Component_Alignment
7870 --------------------------
7871 -- Set_SSO_From_Default --
7872 --------------------------
7877 begin
7878 -- Set default SSO for an array or record base type, except in case of
7879 -- a type extension (which always inherits the SSO of its parent type).
7886 then
7887 Reversed :=
7889 or else
7894 -- For a record type, if bit order is specified explicitly,
7895 -- then do not set SSO from default if not consistent. Note that
7896 -- we do not want to look at a Bit_Order attribute definition
7897 -- for a parent: if we were to inherit Bit_Order, then both
7898 -- SSO_Set_*_By_Default flags would have been cleared already
7899 -- (by Inherit_Aspects_At_Freeze_Point).
7901 and then not
7903 and then
7906 then
7907 -- If flags cause reverse storage order, then set the result. Note
7908 -- that we would have ignored the pragma setting the non default
7909 -- storage order in any case, hence the assertion at this point.
7911 pragma Assert
7916 -- For a record type, also set reversed bit order. Note: if a bit
7917 -- order has been specified explicitly, then this is a no-op.
7926 ------------------
7927 -- Undelay_Type --
7928 ------------------
7931 begin
7935 -- Since we don't want T to have a Freeze_Node, we don't want its
7936 -- Full_View or Corresponding_Record_Type to have one either.
7938 -- ??? Fundamentally, this whole handling is unpleasant. What we really
7939 -- want is to be sure that for an Itype that's part of record R and is a
7940 -- subtype of type T, that it's frozen after the later of the freeze
7941 -- points of R and T. We have no way of doing that directly, so what we
7942 -- do is force most such Itypes to be frozen as part of freezing R via
7943 -- this procedure and only delay the ones that need to be delayed
7944 -- (mostly the designated types of access types that are defined as part
7945 -- of the record).
7951 then
7959 then
7964 ------------------
7965 -- Warn_Overlay --
7966 ------------------
7968 procedure Warn_Overlay
7972 is
7974 -- The object to which the address clause applies
7980 begin
7981 -- No warning if address clause overlay warnings are off
7987 -- No warning if there is an explicit initialization
7995 -- We only give the warning for non-imported entities of a type for
7996 -- which a non-null base init proc is defined, or for objects of access
7997 -- types with implicit null initialization, or when Normalize_Scalars
7998 -- applies and the type is scalar or a string type (the latter being
7999 -- tested for because predefined String types are initialized by inline
8000 -- code rather than by an init_proc). Note that we do not give the
8001 -- warning for Initialize_Scalars, since we suppressed initialization
8002 -- in this case. Also, do not warn if Suppress_Initialization is set.
8012 then
8015 then
8020 then
8027 then
8034 -- A function call (most likely to To_Address) is probably not an
8035 -- overlay, so skip warning. Ditto if the function call was inlined
8036 -- and transformed into an entity.
8042 -- If a pragma Import follows, we assume that it is for the current
8043 -- target of the address clause, and skip the warning. There may be
8044 -- a source pragma or an aspect that specifies import and generates
8045 -- the corresponding pragma. These will indicate that the entity is
8046 -- imported and that is checked above so that the spurious warning
8047 -- (generated when the entity is frozen) will be suppressed. The
8048 -- pragma may be attached to the aspect, so it is not yet a list
8049 -- member.
8057 then
8062 -- Otherwise give warning message
8066 Error_Msg_N
8068 Nam);
8069 else
8070 Error_Msg_N
8072 Nam);
8075 -- Add friendly warning if initialization comes from a packed array
8076 -- component.
8079 declare
8082 begin
8087 then
8091 then
8092 Error_Msg_NE
8097 else
8104 Error_Msg_N
8107 Nam);