| blob | 7612c189b5c75ead426f74f8d8c523b27e9d3c43 |
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
428 Set_Result_Definition
434 -- The body generated for this renaming is an internal artifact, and
435 -- does not constitute a freeze point for the called entity.
442 declare
446 begin
447 -- The controlling formal may be an access parameter, or the
448 -- actual may be an access value, so adjust accordingly.
452 then
453 Actuals := New_List
458 then
459 Actuals :=
460 New_List (
464 else
472 else
483 -- If the renamed entity is an entry, inherit its profile. For other
484 -- renamings as bodies, both profiles must be subtype conformant, so it
485 -- is not necessary to replace the profile given in the declaration.
486 -- However, default values that are aggregates are rewritten when
487 -- partially analyzed, so we recover the original aggregate to insure
488 -- that subsequent conformity checking works. Similarly, if the default
489 -- expression was constant-folded, recover the original expression.
499 N_Access_Definition
500 then
508 then
519 -- If the renamed entity is a function, the generated body contains a
520 -- return statement. Otherwise, build a procedure call. If the entity is
521 -- an entry, subsequent analysis of the call will transform it into the
522 -- proper entry or protected operation call. If the renamed entity is
523 -- a character literal, return it directly.
529 then
530 Call_Node :=
532 Expression =>
538 Call_Node :=
543 Call_Node :=
546 else
547 Call_Node :=
553 -- Create entities for subprogram body and formals
566 Body_Node :=
570 Handled_Statement_Sequence =>
580 -- Link the body to the entity whose declaration it completes. If
581 -- the body is analyzed when the renamed entity is frozen, it may
582 -- be necessary to restore the proper scope (see package Exp_Ch13).
586 then
588 else
595 --------------------------
596 -- Check_Address_Clause --
597 --------------------------
608 begin
615 -- Has_Delayed_Freeze was set on E when the address clause was
616 -- analyzed, and must remain set because we want the address
617 -- clause to be elaborated only after any entity it references
618 -- has been elaborated.
621 -- If Rep_Clauses are to be ignored, remove address clause from
622 -- list attached to entity, because it may be illegal for gigi,
623 -- for example by breaking order of elaboration..
626 declare
629 begin
635 else
638 loop
648 -- And now remove the address clause
654 then
660 -- Capture initialization value at point of declaration,
661 -- and make explicit assignment legal, because object may
662 -- be a constant.
668 -- Move initialization to freeze actions (once the object has
669 -- been frozen, and the address clause alignment check has been
670 -- performed.
679 -- If the objet is tagged, check whether the tag must be
680 -- reassigned expliitly.
690 -----------------------------
691 -- Check_Compile_Time_Size --
692 -----------------------------
697 -- Sets the compile time known size (32 bits or less) in the Esize
698 -- field, of T checking for a size clause that was given which attempts
699 -- to give a smaller size, and also checking for an alignment clause.
702 -- Recursive function that does all the work
705 -- If T is a constrained subtype, its size is not known if any of its
706 -- discriminant constraints is not static and it is not a null record.
707 -- The test is conservative and doesn't check that the components are
708 -- in fact constrained by non-static discriminant values. Could be made
709 -- more precise ???
711 --------------------
712 -- Set_Small_Size --
713 --------------------
716 begin
720 -- Check for bad size clause given
725 Error_Msg_NE
730 -- Set size if not set already
737 ----------------
738 -- Size_Known --
739 ----------------
748 begin
752 -- Always True for scalar types. This is true even for generic formal
753 -- scalar types. We used to return False in the latter case, but the
754 -- size is known at compile time, even in the template, we just do
755 -- not know the exact size but that's not the point of this routine.
759 then
762 -- Array types
766 -- String literals always have known size, and we can set it
773 -- Unconstrained types never have known at compile time size
778 -- Don't do any recursion on type with error posted, since we may
779 -- have a malformed type that leads us into a loop.
784 -- Otherwise if component size unknown, then array size unknown
790 -- Check for all indexes static, and also compute possible size
791 -- (in case it is less than 32 and may be packable).
793 declare
797 begin
806 else
814 then
817 else
822 else
834 -- Access types always have known at compile time sizes
839 -- For non-generic private types, go to underlying type if present
844 then
845 -- Don't do any recursion on type with error posted, since we may
846 -- have a malformed type that leads us into a loop.
850 else
854 -- Record types
858 -- A class-wide type is never considered to have a known size
863 -- A subtype of a variant record must not have non-static
864 -- discriminated components.
868 then
871 -- Don't do any recursion on type with error posted, since we may
872 -- have a malformed type that leads us into a loop.
878 -- Now look at the components of the record
880 declare
881 -- The following two variables are used to keep track of the
882 -- size of packed records if we can tell the size of the packed
883 -- record in the front end. Packed_Size_Known is True if so far
884 -- we can figure out the size. It is initialized to True for a
885 -- packed record, unless the record has discriminants or atomic
886 -- components or independent components.
888 -- The reason we eliminate the discriminated case is that
889 -- we don't know the way the back end lays out discriminated
890 -- packed records. If Packed_Size_Known is True, then
891 -- Packed_Size is the size in bits so far.
900 -- Size in bits so far
902 begin
903 -- Test for variant part present
909 N_Record_Definition
911 and then
912 Present (Variant_Part
914 then
915 -- If variant part is present, and type is unconstrained,
916 -- then we must have defaulted discriminants, or a size
917 -- clause must be present for the type, or else the size
918 -- is definitely not known at compile time.
921 and then
924 then
929 -- Loop through components
935 -- We do not know the packed size if there is a component
936 -- clause present (we possibly could, but this would only
937 -- help in the case of a record with partial rep clauses.
938 -- That's because in the case of full rep clauses, the
939 -- size gets figured out anyway by a different circuit).
945 -- We do not know the packed size if we have an atomic type
946 -- or component, or an independent type or component, or a
947 -- by reference type or aliased component (because packing
948 -- does not touch these).
956 then
960 -- We need to identify a component that is an array where
961 -- the index type is an enumeration type with non-standard
962 -- representation, and some bound of the type depends on a
963 -- discriminant.
965 -- This is because gigi computes the size by doing a
966 -- substitution of the appropriate discriminant value in
967 -- the size expression for the base type, and gigi is not
968 -- clever enough to evaluate the resulting expression (which
969 -- involves a call to rep_to_pos) at compile time.
971 -- It would be nice if gigi would either recognize that
972 -- this expression can be computed at compile time, or
973 -- alternatively figured out the size from the subtype
974 -- directly, where all the information is at hand ???
978 then
979 declare
987 begin
994 then
1000 then
1005 then
1015 -- Clearly size of record is not known if the size of one of
1016 -- the components is not known.
1022 -- Accumulate packed size if possible
1026 -- We can only deal with elementary types, since for
1027 -- non-elementary components, alignment enters into the
1028 -- picture, and we don't know enough to handle proper
1029 -- alignment in this context. Packed arrays count as
1030 -- elementary if the representation is a modular type.
1034 and then Present
1036 and then Is_Modular_Integer_Type
1038 then
1039 -- Packed size unknown if we have an atomic type
1040 -- or a by reference type, since the back end
1041 -- knows how these are layed out.
1045 then
1048 -- If RM_Size is known and static, then we can keep
1049 -- accumulating the packed size
1053 -- A little glitch, to be removed sometime ???
1054 -- gigi does not understand zero sizes yet.
1059 -- Normal case where we can keep accumulating the
1060 -- packed array size.
1062 else
1066 -- If we have a field whose RM_Size is not known then
1067 -- we can't figure out the packed size here.
1069 else
1073 -- If we have a non-elementary type we can't figure out
1074 -- the packed array size (alignment issues).
1076 else
1091 -- All other cases, size not known at compile time
1093 else
1098 -------------------------------------
1099 -- Static_Discriminated_Components --
1100 -------------------------------------
1102 function Static_Discriminated_Components
1104 is
1107 begin
1111 then
1125 -- Start of processing for Check_Compile_Time_Size
1127 begin
1131 -----------------------------------
1132 -- Check_Component_Storage_Order --
1133 -----------------------------------
1135 procedure Check_Component_Storage_Order
1140 is
1146 -- Set for the record case, True if Comp starts on a byte boundary
1147 -- (in which case it is allowed to have different storage order).
1150 -- Set True when the component is a nested composite, and it does not
1151 -- have the same scalar storage order as Encl_Type.
1155 begin
1156 -- Record case
1166 else
1167 -- If a component clause is present, check if the component starts
1168 -- on a storage element boundary. Otherwise conservatively assume
1169 -- it does so only in the case where the record is not packed.
1172 Comp_Byte_Aligned :=
1174 else
1181 -- Array case
1183 else
1190 -- Note: the Reverse_Storage_Order flag is set on the base type, but
1191 -- the attribute definition clause is attached to the first subtype.
1194 Comp_ADC := Get_Attribute_Definition_Clause
1196 Attribute_Scalar_Storage_Order);
1199 -- Case of record or array component: check storage order compatibility
1202 Comp_SSO_Differs :=
1204 /=
1207 -- Parent and extension must have same storage order
1211 Error_Msg_N
1216 -- If enclosing composite has explicit SSO then nested composite must
1217 -- have explicit SSO as well.
1223 -- If component and composite SSO differs, check that component
1224 -- falls on byte boundaries and isn't packed.
1228 -- Component SSO differs from enclosing composite:
1230 -- Reject if component is a packed array, as it may be represented
1231 -- as a scalar internally.
1234 Error_Msg_N
1238 -- Reject if composite is a packed array, as it may be rewritten
1239 -- into an array of scalars.
1245 -- Reject if not byte aligned
1248 and then not Comp_Byte_Aligned
1249 then
1250 Error_Msg_N
1256 -- Enclosing type has explicit SSO: non-composite component must not
1257 -- be aliased.
1260 Error_Msg_N
1266 -----------------------------
1267 -- Check_Debug_Info_Needed --
1268 -----------------------------
1271 begin
1276 or else Debug_Generated_Code
1277 or else Debug_Flag_VV
1279 then
1284 -------------------------------
1285 -- Check_Expression_Function --
1286 -------------------------------
1292 -- Function to search for deferred constant
1294 -------------------
1295 -- Find_Constant --
1296 -------------------
1299 begin
1300 -- When a constant is initialized with the result of a dispatching
1301 -- call, the constant declaration is rewritten as a renaming of the
1302 -- displaced function result. This scenario is not a premature use of
1303 -- a constant even though the Has_Completion flag is not set.
1310 N_Object_Declaration
1313 then
1314 Error_Msg_NE
1322 then
1332 -- Start of processing for Check_Expression_Function
1334 begin
1339 then
1344 ----------------------------
1345 -- Check_Strict_Alignment --
1346 ----------------------------
1351 begin
1369 then
1379 -------------------------
1380 -- Check_Unsigned_Type --
1381 -------------------------
1388 begin
1393 -- Do not attempt to analyze case where range was in error
1399 -- The situation that is non trivial is something like
1401 -- subtype x1 is integer range -10 .. +10;
1402 -- subtype x2 is x1 range 0 .. V1;
1403 -- subtype x3 is x2 range V2 .. V3;
1404 -- subtype x4 is x3 range V4 .. V5;
1406 -- where Vn are variables. Here the base type is signed, but we still
1407 -- know that x4 is unsigned because of the lower bound of x2.
1409 -- The only way to deal with this is to look up the ancestor chain
1412 loop
1426 else
1429 -- If no ancestor had a static lower bound, go to base type
1433 -- Note: the reason we still check for a compile time known
1434 -- value for the base type is that at least in the case of
1435 -- generic formals, we can have bounds that fail this test,
1436 -- and there may be other cases in error situations.
1448 then
1458 -------------------------
1459 -- Is_Atomic_Aggregate --
1460 -------------------------
1462 function Is_Atomic_Aggregate
1465 is
1471 begin
1474 -- Array may be qualified, so find outer context
1482 then
1484 New_N :=
1495 else
1500 -----------------------------------------------
1501 -- Explode_Initialization_Compound_Statement --
1502 -----------------------------------------------
1507 begin
1510 then
1513 -- Note that we rewrite Init_Stmts into a NULL statement, rather than
1514 -- just removing it, because Freeze_All may rely on this particular
1515 -- Node_Id still being present in the enclosing list to know where to
1516 -- stop freezing.
1524 ----------------
1525 -- Freeze_All --
1526 ----------------
1528 -- Note: the easy coding for this procedure would be to just build a
1529 -- single list of freeze nodes and then insert them and analyze them
1530 -- all at once. This won't work, because the analysis of earlier freeze
1531 -- nodes may recursively freeze types which would otherwise appear later
1532 -- on in the freeze list. So we must analyze and expand the freeze nodes
1533 -- as they are generated.
1540 -- This is the internal recursive routine that does freezing of entities
1541 -- (but NOT the analysis of default expressions, which should not be
1542 -- recursive, we don't want to analyze those till we are sure that ALL
1543 -- the types are frozen).
1545 --------------------
1546 -- Freeze_All_Ent --
1547 --------------------
1555 -- If freeze nodes are present, insert and analyze, and reset cursor
1556 -- for next insertion.
1558 -------------------
1559 -- Process_Flist --
1560 -------------------
1563 begin
1570 else
1576 -- Start or processing for Freeze_All_Ent
1578 begin
1582 -- If the entity is an inner package which is not a package
1583 -- renaming, then its entities must be frozen at this point. Note
1584 -- that such entities do NOT get frozen at the end of the nested
1585 -- package itself (only library packages freeze).
1587 -- Same is true for task declarations, where anonymous records
1588 -- created for entry parameters must be frozen.
1594 then
1605 then
1612 N_Single_Task_Declaration)
1613 then
1616 End_Scope;
1618 -- For a derived tagged type, we must ensure that all the
1619 -- primitive operations of the parent have been frozen, so that
1620 -- their addresses will be in the parent's dispatch table at the
1621 -- point it is inherited.
1627 then
1628 declare
1635 begin
1642 then
1644 Process_Flist;
1654 Process_Flist;
1656 -- If already frozen, and there are delayed aspects, this is where
1657 -- we do the visibility check for these aspects (see Sem_Ch13 spec
1658 -- for a description of how we handle aspect visibility).
1662 -- Retrieve the visibility to the discriminants in order to
1663 -- analyze properly the aspects.
1667 declare
1670 begin
1676 then
1687 -- If an incomplete type is still not frozen, this may be a
1688 -- premature freezing because of a body declaration that follows.
1689 -- Indicate where the freezing took place. Freezing will happen
1690 -- if the body comes from source, but not if it is internally
1691 -- generated, for example as the body of a type invariant.
1693 -- If the freezing is caused by the end of the current declarative
1694 -- part, it is a Taft Amendment type, and there is no error.
1698 then
1699 declare
1702 begin
1703 -- The presence of a body freezes all entities previously
1704 -- declared in the current list of declarations, but this
1705 -- does not apply if the body does not come from source.
1706 -- A type invariant is transformed into a subprogram body
1707 -- which is placed at the end of the private part of the
1708 -- current package, but this body does not freeze incomplete
1709 -- types that may be declared in this private part.
1712 N_Entry_Body,
1713 N_Package_Body,
1714 N_Protected_Body,
1715 N_Task_Body)
1717 and then
1720 then
1722 Error_Msg_NE
1733 -- Start of processing for Freeze_All
1735 begin
1738 -- Now that all types are frozen, we can deal with default expressions
1739 -- that require us to build a default expression functions. This is the
1740 -- point at which such functions are constructed (after all types that
1741 -- might be used in such expressions have been frozen).
1743 -- For subprograms that are renaming_as_body, we create the wrapper
1744 -- bodies as needed.
1746 -- We also add finalization chains to access types whose designated
1747 -- types are controlled. This is normally done when freezing the type,
1748 -- but this misses recursive type definitions where the later members
1749 -- of the recursion introduce controlled components.
1751 -- Loop through entities
1766 else
1772 and then
1774 = N_Subprogram_Renaming_Declaration
1775 then
1776 Build_And_Analyze_Renamed_Body
1783 N_Single_Task_Declaration)
1784 then
1785 declare
1788 begin
1793 then
1802 -- Historical note: We used to create a finalization master for an
1803 -- access type whose designated type is not controlled, but contains
1804 -- private controlled compoments. This form of postprocessing is no
1805 -- longer needed because the finalization master is now created when
1806 -- the access type is frozen (see Exp_Ch3.Freeze_Type).
1812 -----------------------
1813 -- Freeze_And_Append --
1814 -----------------------
1816 procedure Freeze_And_Append
1820 is
1822 begin
1826 else
1832 -------------------
1833 -- Freeze_Before --
1834 -------------------
1839 begin
1849 -------------------
1850 -- Freeze_Entity --
1851 -------------------
1855 -- Save the current Ghost mode in effect in case the entity being frozen
1856 -- sets a different mode.
1866 -- This could use a comment ???
1869 -- Used to detect attempt to freeze function declared in another unit
1872 -- List of freezing actions, left at No_List if none
1875 -- This flag gets set to true for a variable with default initialization
1878 -- N is a freezing action to be appended to the Result
1881 -- If Loc is a freeze_entity that appears after the last declaration
1882 -- in the scope, inhibit error messages on late completion.
1885 -- Check that an Access or Unchecked_Access attribute with a prefix
1886 -- which is the current instance type can only be applied when the type
1887 -- is limited.
1890 -- Give warning for modulus of 8, 16, 32, or 64 given as an explicit
1891 -- integer literal without an explicit corresponding size clause. The
1892 -- caller has checked that Utype is a modular integer type.
1895 -- Freeze array type, including freezing index and component types
1898 -- Perform checks and generate freeze node if needed for a constant or
1899 -- variable declared by an object declaration.
1902 -- Create Freeze_Generic_Entity nodes for types declared in a generic
1903 -- package. Recurse on inner generic packages.
1906 -- Freeze formals and return type of subprogram. If some type in the
1907 -- profile is a limited view, freezing of the entity will take place
1908 -- elsewhere, and the function returns False. This routine will be
1909 -- modified if and when we can implement AI05-019 efficiently ???
1912 -- Freeze record type, including freezing component types, and freezing
1913 -- primitive operations if this is a tagged type.
1916 -- Determine whether an arbitrary entity is subject to Boolean aspect
1917 -- Import and its value is specified as True.
1920 -- Following AI05-151, a function can return a limited view of a type
1921 -- declared elsewhere. In that case the function cannot be frozen at
1922 -- the end of its enclosing package. If its first use is in a different
1923 -- unit, it cannot be frozen there, but if the call is legal the full
1924 -- view of the return type is available and the subprogram can now be
1925 -- frozen. However the freeze node cannot be inserted at the point of
1926 -- call, but rather must go in the package holding the function, so that
1927 -- the backend can process it in the proper context.
1930 -- Restore the values of all saved global variables
1933 -- If E is an entity for an imported subprogram with pre/post-conditions
1934 -- then this procedure will create a wrapper to ensure that proper run-
1935 -- time checking of the pre/postconditions. See body for details.
1937 -------------------
1938 -- Add_To_Result --
1939 -------------------
1942 begin
1945 else
1950 ----------------------------
1951 -- After_Last_Declaration --
1952 ----------------------------
1957 begin
1963 else
1967 else
1972 ----------------------------
1973 -- Check_Current_Instance --
1974 ----------------------------
1979 -- Determine whether Typ is compatible with the rules for aliased
1980 -- views of types as defined in RM 3.10 in the various dialects.
1983 -- Process routine to apply check to given node
1985 -----------------------------
1986 -- Is_Aliased_View_Of_Type --
1987 -----------------------------
1992 begin
1993 -- Common case
1997 then
2000 -- The following paragraphs describe what a legal aliased view of
2001 -- a type is in the various dialects of Ada.
2003 -- Ada 95
2005 -- The current instance of a limited type, and a formal parameter
2006 -- or generic formal object of a tagged type.
2008 -- Ada 95 limited type
2009 -- * Type with reserved word "limited"
2010 -- * A protected or task type
2011 -- * A composite type with limited component
2016 -- Ada 2005
2018 -- The current instance of a limited tagged type, a protected
2019 -- type, a task type, or a type that has the reserved word
2020 -- "limited" in its full definition ... a formal parameter or
2021 -- generic formal object of a tagged type.
2023 -- Ada 2005 limited type
2024 -- * Type with reserved word "limited", "synchronized", "task"
2025 -- or "protected"
2026 -- * A composite type with limited component
2027 -- * A derived type whose parent is a non-interface limited type
2030 return
2032 or else
2037 -- Ada 2012 and beyond
2039 -- The current instance of an immutably limited type ... a formal
2040 -- parameter or generic formal object of a tagged type.
2042 -- Ada 2012 limited type
2043 -- * Type with reserved word "limited", "synchronized", "task"
2044 -- or "protected"
2045 -- * A composite type with limited component
2046 -- * A derived type whose parent is a non-interface limited type
2047 -- * An incomplete view
2049 -- Ada 2012 immutably limited type
2050 -- * Explicitly limited record type
2051 -- * Record extension with "limited" present
2052 -- * Non-formal limited private type that is either tagged
2053 -- or has at least one access discriminant with a default
2054 -- expression
2055 -- * Task type, protected type or synchronized interface
2056 -- * Type derived from immutably limited type
2058 else
2059 return
2065 -------------
2066 -- Process --
2067 -------------
2070 begin
2074 Name_Unchecked_Access)
2078 then
2080 Error_Msg_N
2083 else
2084 Error_Msg_N
2091 else
2101 -- Local variables
2106 -- Start of processing for Check_Current_Instance
2108 begin
2114 ------------------------------
2115 -- Check_Suspicious_Modulus --
2116 ------------------------------
2121 begin
2127 declare
2130 begin
2132 declare
2136 begin
2138 declare
2142 begin
2143 -- First case, modulus and size are the same. This
2144 -- happens if you have something like mod 32, with
2145 -- an explicit size of 32, this is for sure a case
2146 -- where the warning is given, since it is seems
2147 -- very unlikely that someone would want e.g. a
2148 -- five bit type stored in 32 bits. It is much
2149 -- more likely they wanted a 32-bit type.
2154 -- Second case, the modulus is 32 or 64 and no
2155 -- size clause is present. This is a less clear
2156 -- case for giving the warning, but in the case
2157 -- of 32/64 (5-bit or 6-bit types) these seem rare
2158 -- enough that it is a likely error (and in any
2159 -- case using 2**5 or 2**6 in these cases seems
2160 -- clearer. We don't include 8 or 16 here, simply
2161 -- because in practice 3-bit and 4-bit types are
2162 -- more common and too many false positives if
2163 -- we warn in these cases.
2167 then
2170 -- No warning needed
2172 else
2176 -- If we fall through, give warning
2179 Error_Msg_N
2181 Modulus);
2190 -----------------------
2191 -- Freeze_Array_Type --
2192 -----------------------
2200 -- Set true if any of the index types is an enumeration type with a
2201 -- non-standard representation.
2203 begin
2212 then
2219 -- Processing that is done only for base types
2223 -- Deal with default setting of reverse storage order
2227 -- Propagate flags for component type
2231 then
2239 -- Warn for pragma Pack overriding foreign convention
2243 then
2244 declare
2249 begin
2253 Error_Msg_N
2256 Error_Msg_N
2263 -- If packing was requested or if the component size was
2264 -- set explicitly, then see if bit packing is required. This
2265 -- processing is only done for base types, since all of the
2266 -- representation aspects involved are type-related.
2268 -- This is not just an optimization, if we start processing the
2269 -- subtypes, they interfere with the settings on the base type
2270 -- (this is because Is_Packed has a slightly different meaning
2271 -- before and after freezing).
2273 declare
2277 begin
2281 then
2290 else
2293 -- We can set the component size if it is less than 16,
2294 -- rounding it up to the next storage unit size.
2300 else
2304 -- Set component size up to match alignment if it would
2305 -- otherwise be less than the alignment. This deals with
2306 -- cases of types whose alignment exceeds their size (the
2307 -- padded type cases).
2310 declare
2312 begin
2320 -- Case of component size that may result in packing
2323 declare
2329 Get_Attribute_Definition_Clause
2332 begin
2333 -- Warn if we have pack and component size so that the
2334 -- pack is ignored.
2336 -- Note: here we must check for the presence of a
2337 -- component size before checking for a Pack pragma to
2338 -- deal with the case where the array type is a derived
2339 -- type whose parent is currently private.
2343 and then Warn_On_Redundant_Constructs
2344 then
2346 Error_Msg_NE
2348 Error_Msg_N
2354 -- Set component size if not already set by a component
2355 -- size clause.
2361 -- Check for base type of 8, 16, 32 bits, where an
2362 -- unsigned subtype has a length one less than the
2363 -- base type (e.g. Natural subtype of Integer).
2365 -- In such cases, if a component size was not set
2366 -- explicitly, then generate a warning.
2372 then
2376 Error_Msg_N
2378 Pack_Pragma);
2379 Error_Msg_N
2381 Pack_Pragma);
2385 -- Actual packing is not needed for 8, 16, 32, 64. Also
2386 -- not needed for 24 if alignment is 1.
2393 then
2394 -- Here the array was requested to be packed, but
2395 -- the packing request had no effect, so Is_Packed
2396 -- is reset.
2398 -- Note: semantically this means that we lose track
2399 -- of the fact that a derived type inherited a pragma
2400 -- Pack that was non- effective, but that seems fine.
2402 -- We regard a Pack pragma as a request to set a
2403 -- representation characteristic, and this request
2404 -- may be ignored.
2411 then
2415 -- In all other cases, packing is indeed needed
2417 else
2426 -- Check for Aliased or Atomic_Components/Atomic with unsuitable
2427 -- packing or explicit component size clause given.
2432 and then
2434 then
2438 -- Outputs error messages for incorrect CS clause or pragma
2439 -- Pack for aliased or atomic components (T is "aliased" or
2440 -- "atomic");
2442 -----------------
2443 -- Complain_CS --
2444 -----------------
2447 begin
2449 Clause :=
2450 Get_Attribute_Definition_Clause
2453 Error_Msg_N
2457 Error_Msg_N
2460 else
2461 Error_Msg_N
2467 -- Start of processing for Alias_Atomic_Check
2469 begin
2470 -- If object size of component type isn't known, we cannot
2471 -- be sure so we defer to the back end.
2476 -- Case where component size has no effect. First check for
2477 -- object size of component type multiple of the storage
2478 -- unit size.
2482 -- OK in both packing case and component size case if RM
2483 -- size is known and static and same as the object size.
2485 and then
2489 -- Or if we have an explicit component size clause and
2490 -- the component size and object size are equal.
2492 or else
2495 then
2502 then
2508 -- Check for Independent_Components/Independent with unsuitable
2509 -- packing or explicit component size clause given.
2512 and then
2514 then
2515 begin
2516 -- If object size of component type isn't known, we cannot
2517 -- be sure so we defer to the back end.
2522 -- Case where component size has no effect. First check for
2523 -- object size of component type multiple of the storage
2524 -- unit size.
2528 -- OK in both packing case and component size case if RM
2529 -- size is known and multiple of the storage unit size.
2531 and then
2535 -- Or if we have an explicit component size clause and
2536 -- the component size is larger than the object size.
2538 or else
2541 then
2544 else
2546 Clause :=
2547 Get_Attribute_Definition_Clause
2550 Error_Msg_N
2554 Error_Msg_N
2557 else
2558 Error_Msg_N
2566 -- Warn for case of atomic type
2572 then
2573 Error_Msg_NE
2588 -- Check for scalar storage order
2590 declare
2592 begin
2593 Check_Component_Storage_Order
2596 ADC => Get_Attribute_Definition_Clause
2598 Attribute_Scalar_Storage_Order),
2602 -- Processing that is done only for subtypes
2604 else
2605 -- Acquire alignment from base type
2613 -- Specific checks for bit-packed arrays
2617 -- Check number of elements for bit packed arrays that come from
2618 -- source and have compile time known ranges. The bit-packed
2619 -- arrays circuitry does not support arrays with more than
2620 -- Integer'Last + 1 elements, and when this restriction is
2621 -- violated, causes incorrect data access.
2623 -- For the case where this is not compile time known, a run-time
2624 -- check should be generated???
2627 declare
2633 begin
2639 -- Never generate an error if any index is of a generic
2640 -- type. We will check this in instances.
2647 Ilen :=
2653 -- No attempt is made to check number of elements if not
2654 -- compile time known.
2667 then
2668 Error_Msg_N
2675 -- Check size
2678 declare
2682 begin
2683 -- It is not clear if it is possible to have no size clause
2684 -- at this stage, but it is not worth worrying about. Post
2685 -- error on the entity name in the size clause if present,
2686 -- else on the type entity itself.
2690 else
2697 -- If any of the index types was an enumeration type with a non-
2698 -- standard rep clause, then we indicate that the array type is
2699 -- always packed (even if it is not bit packed).
2708 -- If the array is packed, we must create the packed array type to be
2709 -- used to actually implement the type. This is only needed for real
2710 -- array types (not for string literal types, since they are present
2711 -- only for the front end).
2715 then
2719 -- Make sure that we have the necessary routines to implement the
2720 -- packing, and complain now if not. Note that we only test this
2721 -- for constrained array types.
2727 then
2728 declare
2732 begin
2735 then
2736 Error_Msg_CRT
2740 -- Cancel the packing
2750 -- Size information of packed array type is copied to the array
2751 -- type, since this is really the representation. But do not
2752 -- override explicit existing size values. If the ancestor subtype
2753 -- is constrained the Packed_Array_Impl_Type will be inherited
2754 -- from it, but the size may have been provided already, and
2755 -- must not be overridden either.
2758 and then
2761 then
2773 -- For non-packed arrays set the alignment of the array to the
2774 -- alignment of the component type if it is unknown. Skip this
2775 -- in atomic case (atomic arrays may need larger alignments).
2784 then
2789 -------------------------------
2790 -- Freeze_Object_Declaration --
2791 -------------------------------
2794 begin
2795 -- Abstract type allowed only for C++ imported variables or constants
2797 -- Note: we inhibit this check for objects that do not come from
2798 -- source because there is at least one case (the expansion of
2799 -- x'Class'Input where x is abstract) where we legitimately
2800 -- generate an abstract object.
2805 then
2810 Error_Msg_NE
2815 Error_Msg_N -- CODEFIX
2821 -- For object created by object declaration, perform required
2822 -- categorization (preelaborate and pure) checks. Defer these
2823 -- checks to freeze time since pragma Import inhibits default
2824 -- initialization and thus pragma Import affects these checks.
2828 -- If there is an address clause, check that it is valid
2829 -- and if need be move initialization to the freeze node.
2833 -- Similar processing is needed for aspects that may affect
2834 -- object layout, like Alignment, if there is an initialization
2835 -- expression.
2838 and then Expander_Active
2841 then
2842 declare
2846 begin
2848 -- Capture initialization value at point of declaration, and
2849 -- make explicit assignment legal, because object may be a
2850 -- constant.
2855 -- Move initialization to freeze actions.
2863 -- Set_Is_Frozen (E, False);
2867 -- Reset Is_True_Constant for non-constant aliased object. We
2868 -- consider that the fact that a non-constant object is aliased may
2869 -- indicate that some funny business is going on, e.g. an aliased
2870 -- object is passed by reference to a procedure which captures the
2871 -- address of the object, which is later used to assign a new value,
2872 -- even though the compiler thinks that it is not modified. Such
2873 -- code is highly dubious, but we choose to make it "work" for
2874 -- non-constant aliased objects.
2876 -- Note that we used to do this for all aliased objects, whether or
2877 -- not constant, but this caused anomalies down the line because we
2878 -- ended up with static objects that were not Is_True_Constant. Not
2879 -- resetting Is_True_Constant for (aliased) constant objects ensures
2880 -- that this anomaly never occurs.
2882 -- However, we don't do that for internal entities. We figure that if
2883 -- we deliberately set Is_True_Constant for an internal entity, e.g.
2884 -- a dispatch table entry, then we mean it.
2889 then
2893 -- If the object needs any kind of default initialization, an error
2894 -- must be issued if No_Default_Initialization applies. The check
2895 -- doesn't apply to imported objects, which are not ever default
2896 -- initialized, and is why the check is deferred until freezing, at
2897 -- which point we know if Import applies. Deferred constants are also
2898 -- exempted from this test because their completion is explicit, or
2899 -- through an import pragma.
2907 and then
2912 or else
2915 then
2917 Check_Restriction
2921 -- Check that a Thread_Local_Storage variable does not have
2922 -- default initialization, and any explicit initialization must
2923 -- either be the null constant or a static constant.
2926 declare
2928 begin
2929 if Has_Default_Initialization
2930 or else
2932 and then
2934 or else not
2937 then
2938 Error_Msg_NE
2941 Error_Msg_NE
2948 -- For imported objects, set Is_Public unless there is also an
2949 -- address clause, which means that there is no external symbol
2950 -- needed for the Import (Is_Public may still be set for other
2951 -- unrelated reasons). Note that we delayed this processing
2952 -- till freeze time so that we can be sure not to set the flag
2953 -- if there is an address clause. If there is such a clause,
2954 -- then the only purpose of the Import pragma is to suppress
2955 -- implicit initialization.
2961 -- For source objects that are not Imported and are library
2962 -- level, if no linker section pragma was given inherit the
2963 -- appropriate linker section from the corresponding type.
2969 then
2970 Set_Linker_Section_Pragma
2974 -- For convention C objects of an enumeration type, warn if the
2975 -- size is not integer size and no explicit size given. Skip
2976 -- warning for Boolean, and Character, assume programmer expects
2977 -- 8-bit sizes for these cases.
2980 or else
2987 then
2989 Error_Msg_N
2995 -----------------------------
2996 -- Freeze_Generic_Entities --
2997 -----------------------------
3004 begin
3023 --------------------
3024 -- Freeze_Profile --
3025 --------------------
3032 begin
3033 -- Loop through formals
3039 -- AI05-0151: incomplete types can appear in a profile. By the
3040 -- time the entity is frozen, the full view must be available,
3041 -- unless it is a limited view.
3046 then
3058 then
3059 -- If the type of a formal is incomplete, subprogram is being
3060 -- frozen prematurely. Within an instance (but not within a
3061 -- wrapper package) this is an artifact of our need to regard
3062 -- the end of an instantiation as a freeze point. Otherwise it
3063 -- is a definite error.
3070 elsif not After_Last_Declaration
3071 and then not Freezing_Library_Level_Tagged_Type
3072 then
3074 Error_Msg
3079 -- Check suspicious parameter for C function. These tests apply
3080 -- only to exported/imported subprograms.
3082 if Warn_On_Export_Import
3085 or else
3092 then
3093 -- Qualify mention of formals with subprogram name
3097 -- Check suspicious use of fat C pointer
3101 then
3102 Error_Msg_N
3105 -- Check suspicious return of boolean
3112 then
3113 Error_Msg_N
3115 Error_Msg_N
3119 -- Check suspicious tagged type
3122 or else
3126 then
3127 Error_Msg_N
3131 -- Check wrong convention subprogram pointer
3135 then
3136 Error_Msg_N
3140 Error_Msg_NE
3145 -- Turn off name qualification after message output
3150 -- Check for unconstrained array in exported foreign convention
3151 -- case.
3157 and then Warn_On_Export_Import
3159 -- Exclude VM case, since both .NET and JVM can handle
3160 -- unconstrained arrays without a problem.
3163 then
3166 -- If this is an inherited operation, place the warning on
3167 -- the derived type declaration, rather than on the original
3168 -- subprogram.
3171 then
3177 else
3193 -- If the formal is an anonymous_access_to_subprogram
3194 -- freeze the subprogram type as well, to prevent
3195 -- scope anomalies in gigi, because there is no other
3196 -- clear point at which it could be frozen.
3200 then
3208 -- Case of function: similar checks on return type
3212 -- Check whether function is declared elsewhere.
3214 Late_Freezing :=
3219 -- Freeze return type
3223 -- AI05-0151: the return type may have been incomplete
3224 -- at the point of declaration. Replace it with the full
3225 -- view, unless the current type is a limited view. In
3226 -- that case the full view is in a different unit, and
3227 -- gigi finds the non-limited view after the other unit
3228 -- is elaborated.
3233 then
3237 -- If the return type is a limited view and the non-limited
3238 -- view is still incomplete, the function has to be frozen at a
3239 -- later time. If the function is abstract there is no place at
3240 -- which the full view will become available, and no code to be
3241 -- generated for it, so mark type as frozen.
3246 then
3249 else
3258 -- Check suspicious return type for C function
3260 if Warn_On_Export_Import
3262 or else
3265 then
3266 -- Check suspicious return of fat C pointer
3272 then
3276 -- Check suspicious return of boolean
3284 then
3285 declare
3288 begin
3289 Error_Msg_NE
3291 Error_Msg_NE
3296 -- Check suspicious return tagged type
3300 and then
3301 Is_Tagged_Type
3306 then
3310 -- Check return of wrong convention subprogram pointer
3316 then
3320 Error_Msg_NE
3326 -- Give warning for suspicious return of a result of an
3327 -- unconstrained array type in a foreign convention function.
3331 -- We are looking for a return of unconstrained array
3336 -- Exclude imported routines, the warning does not belong on
3337 -- the import, but rather on the routine definition.
3341 -- Exclude VM case, since both .NET and JVM can handle return
3342 -- of unconstrained arrays without a problem.
3346 -- Check that general warning is enabled, and that it is not
3347 -- suppressed for this particular case.
3349 and then Warn_On_Export_Import
3352 then
3358 -- Check suspicious use of Import in pure unit
3362 -- Ignore internally generated entity. This happens in some cases
3363 -- of subprograms in specs, where we generate an implied body.
3367 -- Assume run-time knows what it is doing
3369 and then not GNAT_Mode
3371 -- Assume explicit Pure_Function means import is pure
3375 -- Don't need warning in relaxed semantics mode
3377 and then not Relaxed_RM_Semantics
3379 -- Assume convention Intrinsic is OK, since this is specialized.
3380 -- This deals with the DEC unit current_exception.ads
3384 -- Assume that ASM interface knows what it is doing. This deals
3385 -- with unsigned.ads in the AAMP back end.
3388 then
3389 Error_Msg_N
3391 Error_Msg_NE
3399 ------------------------
3400 -- Freeze_Record_Type --
3401 ------------------------
3413 -- Set True if the record type scope Rec has been pushed on the scope
3414 -- stack. Needed for the analysis of delayed aspects specified to the
3415 -- components of Rec.
3418 -- Scalar_Storage_Order attribute definition clause for the record
3421 -- Set True if we find at least one component with no component
3422 -- clause (used to warn about useless Pack pragmas).
3425 -- Set True if we find at least one component with a component
3426 -- clause (used to warn about useless Bit_Order pragmas, and also
3427 -- to detect cases where Implicit_Packing may have an effect).
3430 -- Set True if we find at least one component which is aliased. This
3431 -- is used to prevent Implicit_Packing of the record, since packing
3432 -- cannot modify the size of alignment of an aliased component.
3435 -- Set True if we find at least one component whose type has a
3436 -- Scalar_Storage_Order attribute definition clause.
3439 -- Set False if we encounter a component of a non-scalar type
3443 -- Accumulates total RM_Size values and total Esize values of all
3444 -- scalar components. Used for processing of Implicit_Packing.
3447 -- If N is an allocator, possibly wrapped in one or more level of
3448 -- qualified expression(s), return the inner allocator node, else
3449 -- return Empty.
3452 -- If the component subtype is an access to a constrained subtype of
3453 -- an already frozen type, make the subtype frozen as well. It might
3454 -- otherwise be frozen in the wrong scope, and a freeze node on
3455 -- subtype has no effect. Similarly, if the component subtype is a
3456 -- regular (not protected) access to subprogram, set the anonymous
3457 -- subprogram type to frozen as well, to prevent an out-of-scope
3458 -- freeze node at some eventual point of call. Protected operations
3459 -- are handled elsewhere.
3462 -- Make sure that all types mentioned in Discrete_Choices of the
3463 -- variants referenceed by the Variant_Part VP are frozen. This is
3464 -- a recursive routine to deal with nested variants.
3466 ---------------------
3467 -- Check_Allocator --
3468 ---------------------
3472 begin
3474 loop
3479 else
3485 -----------------
3486 -- Check_Itype --
3487 -----------------
3492 begin
3495 then
3498 -- In addition, add an Itype_Reference to ensure that the
3499 -- access subtype is elaborated early enough. This cannot be
3500 -- done if the subtype may depend on discriminants.
3505 then
3513 then
3518 ------------------------------------
3519 -- Freeze_Choices_In_Variant_Part --
3520 ------------------------------------
3529 begin
3530 -- Loop through variants
3535 -- Loop through choices, checking that all types are frozen
3541 then
3548 -- Check for nested variant part to process
3562 -- Start of processing for Freeze_Record_Type
3564 begin
3565 -- Deal with delayed aspect specifications for components. The
3566 -- analysis of the aspect is required to be delayed to the freeze
3567 -- point, thus we analyze the pragma or attribute definition
3568 -- clause in the tree at this point. We also analyze the aspect
3569 -- specification node at the freeze point when the aspect doesn't
3570 -- correspond to pragma/attribute definition clause.
3576 then
3581 -- The visibility to the discriminants must be restored in
3582 -- order to properly analyze the aspects.
3595 -- Pop the scope if Rec scope has been pushed on the scope stack
3596 -- during the delayed aspect analysis process.
3603 Pop_Scope;
3606 -- Freeze components and embedded subtypes
3615 -- Handle the component and discriminant case
3618 declare
3621 begin
3622 -- Freezing a record type freezes the type of each of its
3623 -- components. However, if the type of the component is
3624 -- part of this record, we do not want or need a separate
3625 -- Freeze_Node. Note that Is_Itype is wrong because that's
3626 -- also set in private type cases. We also can't check for
3627 -- the Scope being exactly Rec because of private types and
3628 -- record extensions.
3633 then
3639 -- Warn for pragma Pack overriding foreign convention
3644 -- Don't warn for aliased components, since override
3645 -- cannot happen in that case.
3648 then
3649 declare
3654 begin
3658 Error_Msg_N
3660 PP);
3662 Error_Msg_NE
3669 -- Check for error of component clause given for variable
3670 -- sized type. We have to delay this test till this point,
3671 -- since the component type has to be frozen for us to know
3672 -- if it is variable length.
3677 -- We omit this test in a generic context, it will be
3678 -- applied at instantiation time.
3683 -- Also omit this test in CodePeer mode, since we do not
3684 -- have sufficient info on size and rep clauses.
3689 -- Omit check if component has a generic type. This can
3690 -- happen in an instantiation within a generic in ASIS
3691 -- mode, where we force freeze actions without full
3692 -- expansion.
3697 -- Do the check
3699 elsif not
3700 Size_Known_At_Compile_Time
3702 then
3703 Error_Msg_N
3708 else
3712 -- Case of component requires byte alignment
3716 -- Set the enclosing record to also require byte align
3720 -- Check for component clause that is inconsistent with
3721 -- the required byte boundary alignment.
3726 then
3727 Error_Msg_N
3735 -- Gather data for possible Implicit_Packing later. Note that at
3736 -- this stage we might be dealing with a real component, or with
3737 -- an implicit subtype declaration.
3741 else
3742 Scalar_Component_Total_RM_Size :=
3744 Scalar_Component_Total_Esize :=
3748 -- If the component is an Itype with Delayed_Freeze and is either
3749 -- a record or array subtype and its base type has not yet been
3750 -- frozen, we must remove this from the entity list of this record
3751 -- and put it on the entity list of the scope of its base type.
3752 -- Note that we know that this is not the type of a component
3753 -- since we cleared Has_Delayed_Freeze for it in the previous
3754 -- loop. Thus this must be the Designated_Type of an access type,
3755 -- which is the type of a component.
3763 then
3764 declare
3768 begin
3769 -- We have a difficult case to handle here. Suppose Rec is
3770 -- subtype being defined in a subprogram that's created as
3771 -- part of the freezing of Rec'Base. In that case, we know
3772 -- that Comp'Base must have already been frozen by the time
3773 -- we get to elaborate this because Gigi doesn't elaborate
3774 -- any bodies until it has elaborated all of the declarative
3775 -- part. But Is_Frozen will not be set at this point because
3776 -- we are processing code in lexical order.
3778 -- We detect this case by going up the Scope chain of Rec
3779 -- and seeing if we have a subprogram scope before reaching
3780 -- the top of the scope chain or that of Comp'Base. If we
3781 -- do, then mark that Comp'Base will actually be frozen. If
3782 -- so, we merely undelay it.
3799 else
3802 else
3806 -- Insert in entity list of scope of base type (which
3807 -- must be an enclosing scope, because still unfrozen).
3813 -- If the component is an access type with an allocator as default
3814 -- value, the designated type will be frozen by the corresponding
3815 -- expression in init_proc. In order to place the freeze node for
3816 -- the designated type before that for the current record type,
3817 -- freeze it now.
3819 -- Same process if the component is an array of access types,
3820 -- initialized with an aggregate. If the designated type is
3821 -- private, it cannot contain allocators, and it is premature
3822 -- to freeze the type, so we check for this as well.
3827 then
3828 declare
3832 begin
3835 -- If component is pointer to a class-wide type, freeze
3836 -- the specific type in the expression being allocated.
3837 -- The expression may be a subtype indication, in which
3838 -- case freeze the subtype mark.
3840 if Is_Class_Wide_Type
3842 then
3844 Freeze_And_Append
3848 then
3849 Freeze_And_Append
3857 else
3858 Freeze_And_Append
3866 then
3869 -- Freeze the designated type when initializing a component with
3870 -- an aggregate in case the aggregate contains allocators.
3872 -- type T is ...;
3873 -- type T_Ptr is access all T;
3874 -- type T_Array is array ... of T_Ptr;
3876 -- type Rec is record
3877 -- Comp : T_Array := (others => ...);
3878 -- end record;
3882 then
3883 declare
3886 Designated_Type
3889 begin
3890 -- The only case when this sort of freezing is not done is
3891 -- when the designated type is class-wide and the root type
3892 -- is the record owning the component. This scenario results
3893 -- in a circularity because the class-wide type requires
3894 -- primitives that have not been created yet as the root
3895 -- type is in the process of being frozen.
3897 -- type Rec is tagged;
3898 -- type Rec_Ptr is access all Rec'Class;
3899 -- type Rec_Array is array ... of Rec_Ptr;
3901 -- type Rec is record
3902 -- Comp : Rec_Array := (others => ...);
3903 -- end record;
3907 then
3915 then
3925 -- Deal with default setting of reverse storage order
3929 -- Check consistent attribute setting on component types
3931 SSO_ADC := Get_Attribute_Definition_Clause
3934 declare
3936 begin
3939 Check_Component_Storage_Order
3949 -- Now deal with reverse storage order/bit order issues
3953 -- Check compatibility of Scalar_Storage_Order with Bit_Order, if
3954 -- the former is specified.
3958 -- Note: report error on Rec, not on SSO_ADC, as ADC may apply
3959 -- to some ancestor type.
3962 Error_Msg_N
3967 -- Warn if there is an Scalar_Storage_Order attribute definition
3968 -- clause but no component clause, no component that itself has
3969 -- such an attribute definition, and no pragma Pack.
3972 or else
3973 SSO_ADC_Component
3974 or else
3976 then
3977 Error_Msg_N
3979 SSO_ADC);
3983 -- Deal with Bit_Order aspect
3991 then
3992 -- Warn if clause has no effect when no component clause is
3993 -- present, but suppress warning if the Bit_Order is required
3994 -- due to the presence of a Scalar_Storage_Order attribute.
3996 Error_Msg_N
3998 Error_Msg_N
4001 -- Here is where we do the processing to adjust component clauses
4002 -- for reversed bit order, when not using reverse SSO.
4006 then
4009 -- Case where we have both an explicit Bit_Order and the same
4010 -- Scalar_Storage_Order: leave record untouched, the back-end
4011 -- will take care of required layout conversions.
4013 else
4019 -- Complete error checking on record representation clause (e.g.
4020 -- overlap of components). This is called after adjusting the
4021 -- record for reverse bit order.
4023 declare
4025 begin
4031 -- Set OK_To_Reorder_Components depending on debug flags
4035 or else
4037 then
4042 -- Check for useless pragma Pack when all components placed. We only
4043 -- do this check for record types, not subtypes, since a subtype may
4044 -- have all its components placed, and it still makes perfectly good
4045 -- sense to pack other subtypes or the parent type. We do not give
4046 -- this warning if Optimize_Alignment is set to Space, since the
4047 -- pragma Pack does have an effect in this case (it always resets
4048 -- the alignment to one).
4052 and then not Unplaced_Component
4054 then
4055 -- Reset packed status. Probably not necessary, but we do it so
4056 -- that there is no chance of the back end doing something strange
4057 -- with this redundant indication of packing.
4061 -- Give warning if redundant constructs warnings on
4064 Error_Msg_N -- CODEFIX
4070 -- If this is the record corresponding to a remote type, freeze the
4071 -- remote type here since that is what we are semantically freezing.
4072 -- This prevents the freeze node for that type in an inner scope.
4079 -- Check for controlled components and unchecked unions.
4084 -- Do not set Has_Controlled_Component on a class-wide
4085 -- equivalent type. See Make_CW_Equivalent_Type.
4088 and then
4090 or else
4093 or else
4095 and then
4097 and then
4098 Has_Controlled_Component
4100 then
4108 -- Scan component declaration for likely misuses of current
4109 -- instance, either in a constraint or a default expression.
4119 -- Enforce the restriction that access attributes with a current
4120 -- instance prefix can only apply to limited types. This comment
4121 -- is floating here, but does not seem to belong here???
4123 -- Set component alignment if not otherwise already set
4127 -- For first subtypes, check if there are any fixed-point fields with
4128 -- component clauses, where we must check the size. This is not done
4129 -- till the freeze point since for fixed-point types, we do not know
4130 -- the size until the type is frozen. Similar processing applies to
4131 -- bit packed arrays.
4139 then
4140 Check_Size
4144 Junk);
4151 -- Generate warning for applying C or C++ convention to a record
4152 -- with discriminants. This is suppressed for the unchecked union
4153 -- case, since the whole point in this case is interface C. We also
4154 -- do not generate this within instantiations, since we will have
4155 -- generated a message on the template.
4160 or else
4163 and then not In_Instance
4166 then
4167 declare
4171 begin
4176 Error_Msg_N
4178 A2);
4179 else
4180 Error_Msg_N
4182 A2);
4185 Error_Msg_NE
4191 -- See if Size is too small as is (and implicit packing might help)
4195 -- No implicit packing if even one component is explicitly placed
4197 and then not Placed_Component
4199 -- Or even one component is aliased
4201 and then not Aliased_Component
4203 -- Must have size clause and all scalar components
4206 and then All_Scalar_Components
4208 -- Do not try implicit packing on records with discriminants, too
4209 -- complicated, especially in the variant record case.
4213 -- We can implicitly pack if the specified size of the record is
4214 -- less than the sum of the object sizes (no point in packing if
4215 -- this is not the case).
4219 -- And the total RM size cannot be greater than the specified size
4220 -- since otherwise packing will not get us where we have to be.
4224 -- Never do implicit packing in CodePeer or SPARK modes since
4225 -- we don't do any packing in these modes, since this generates
4226 -- over-complex code that confuses static analysis, and in
4227 -- general, neither CodePeer not GNATprove care about the
4228 -- internal representation of objects.
4231 then
4232 -- If implicit packing enabled, do it
4237 -- Otherwise flag the size clause
4239 else
4240 declare
4242 begin
4243 Error_Msg_NE -- CODEFIX
4245 Error_Msg_N -- CODEFIX
4252 -- The following checks are only relevant when SPARK_Mode is on as
4253 -- they are not standard Ada legality rules.
4258 -- A discriminated type cannot be effectively volatile
4259 -- (SPARK RM C.6(4)).
4264 -- A tagged type cannot be effectively volatile
4265 -- (SPARK RM C.6(5)).
4271 -- A non-effectively volatile record type cannot contain
4272 -- effectively volatile components (SPARK RM C.6(2)).
4274 else
4279 then
4281 Error_Msg_N
4291 -- All done if not a full record definition
4297 -- Finally we need to check the variant part to make sure that
4298 -- all types within choices are properly frozen as part of the
4299 -- freezing of the record type.
4306 begin
4307 -- Find component list
4319 then
4324 -- Case of variant part present
4330 -- Note: we used to call Check_Choices here, but it is too early,
4331 -- since predicated subtypes are frozen here, but their freezing
4332 -- actions are in Analyze_Freeze_Entity, which has not been called
4333 -- yet for entities frozen within this procedure, so we moved that
4334 -- call to the Analyze_Freeze_Entity for the record type.
4338 -- Check that all the primitives of an interface type are abstract
4339 -- or null procedures.
4343 then
4344 declare
4348 begin
4355 -- Avoid reporting the error on inherited primitives
4358 then
4363 Error_Msg_N
4367 else
4368 Error_Msg_N
4380 -------------------------------
4381 -- Has_Boolean_Aspect_Import --
4382 -------------------------------
4389 begin
4395 -- The value of aspect Import is True when the expression is
4396 -- either missing or it is explicitly set to True.
4402 then
4413 ----------------------------
4414 -- Late_Freeze_Subprogram --
4415 ----------------------------
4422 begin
4425 else
4432 ---------------------
4433 -- Restore_Globals --
4434 ---------------------
4437 begin
4441 ------------------------------
4442 -- Wrap_Imported_Subprogram --
4443 ------------------------------
4445 -- The issue here is that our normal approach of checking preconditions
4446 -- and postconditions does not work for imported procedures, since we
4447 -- are not generating code for the body. To get around this we create
4448 -- a wrapper, as shown by the following example:
4450 -- procedure K (A : Integer);
4451 -- pragma Import (C, K);
4453 -- The spec is rewritten by removing the effects of pragma Import, but
4454 -- leaving the convention unchanged, as though the source had said:
4456 -- procedure K (A : Integer);
4457 -- pragma Convention (C, K);
4459 -- and we create a body, added to the entity K freeze actions, which
4460 -- looks like:
4462 -- procedure K (A : Integer) is
4463 -- procedure K (A : Integer);
4464 -- pragma Import (C, K);
4465 -- begin
4466 -- K (A);
4467 -- end K;
4469 -- Now the contract applies in the normal way to the outer procedure,
4470 -- and the inner procedure has no contracts, so there is no problem
4471 -- in just calling it to get the original effect.
4473 -- In the case of a function, we create an appropriate return statement
4474 -- for the subprogram body that calls the inner procedure.
4486 begin
4487 -- Nothing to do if not imported
4492 -- Test enabling conditions for wrapping
4497 and then not GNATprove_Mode
4498 then
4499 -- Here we do the wrap
4501 -- Note on calls to Copy_Separate_Tree. The trees we are copying
4502 -- here are fully analyzed, but we definitely want fully syntactic
4503 -- unanalyzed trees in the body we construct, so that the analysis
4504 -- generates the right visibility, and that is exactly what the
4505 -- calls to Copy_Separate_Tree give us.
4507 -- Acquire copy of Inline pragma, and indicate that it does not
4508 -- come from an aspect, as it applies to an internal entity.
4513 -- Fix up spec to be not imported any more
4520 -- Grab the subprogram declaration and specification
4524 -- Build parameter list that we need
4533 -- Build the call
4536 Stmt :=
4538 Expression =>
4543 else
4544 Stmt :=
4550 -- Now build the body
4552 Bod :=
4554 Specification =>
4558 Specification =>
4560 Iprag),
4561 Handled_Statement_Sequence =>
4566 -- Append the body to freeze result
4571 -- Case of imported subprogram that does not get wrapped
4573 else
4574 -- Set Is_Public. All imported entities need an external symbol
4575 -- created for them since they are always referenced from another
4576 -- object file. Note this used to be set when we set Is_Imported
4577 -- back in Sem_Prag, but now we delay it to this point, since we
4578 -- don't want to set this flag if we wrap an imported subprogram.
4584 -- Start of processing for Freeze_Entity
4586 begin
4587 -- The entity being frozen may be subject to pragma Ghost with policy
4588 -- Ignore. Set the mode now to ensure that any nodes generated during
4589 -- freezing are properly flagged as ignored Ghost.
4593 -- We are going to test for various reasons why this entity need not be
4594 -- frozen here, but in the case of an Itype that's defined within a
4595 -- record, that test actually applies to the record.
4601 then
4605 -- Do not freeze if already frozen since we only need one freeze node
4608 Restore_Globals;
4611 -- It is improper to freeze an external entity within a generic because
4612 -- its freeze node will appear in a non-valid context. The entity will
4613 -- be frozen in the proper scope after the current generic is analyzed.
4614 -- However, aspects must be analyzed because they may be queried later
4615 -- within the generic itself, and the corresponding pragma or attribute
4616 -- definition has not been analyzed yet.
4623 Restore_Globals;
4626 -- AI05-0213: A formal incomplete type does not freeze the actual. In
4627 -- the instance, the same applies to the subtype renaming the actual.
4633 then
4634 Restore_Globals;
4637 -- Formal subprograms are never frozen
4640 Restore_Globals;
4643 -- Generic types are never frozen as they lack delayed semantic checks
4646 Restore_Globals;
4649 -- Do not freeze a global entity within an inner scope created during
4650 -- expansion. A call to subprogram E within some internal procedure
4651 -- (a stream attribute for example) might require freezing E, but the
4652 -- freeze node must appear in the same declarative part as E itself.
4653 -- The two-pass elaboration mechanism in gigi guarantees that E will
4654 -- be frozen before the inner call is elaborated. We exclude constants
4655 -- from this test, because deferred constants may be frozen early, and
4656 -- must be diagnosed (e.g. in the case of a deferred constant being used
4657 -- in a default expression). If the enclosing subprogram comes from
4658 -- source, or is a generic instance, then the freeze point is the one
4659 -- mandated by the language, and we freeze the entity. A subprogram that
4660 -- is a child unit body that acts as a spec does not have a spec that
4661 -- comes from source, but can only come from source.
4666 then
4667 declare
4670 begin
4677 then
4679 else
4680 Restore_Globals;
4689 -- Similarly, an inlined instance body may make reference to global
4690 -- entities, but these references cannot be the proper freezing point
4691 -- for them, and in the absence of inlining freezing will take place in
4692 -- their own scope. Normally instance bodies are analyzed after the
4693 -- enclosing compilation, and everything has been frozen at the proper
4694 -- place, but with front-end inlining an instance body is compiled
4695 -- before the end of the enclosing scope, and as a result out-of-order
4696 -- freezing must be prevented.
4698 elsif Front_End_Inlining
4699 and then In_Instance_Body
4701 then
4702 declare
4705 begin
4710 else
4716 Restore_Globals;
4724 Restore_Globals;
4728 -- Add checks to detect proper initialization of scalars that may appear
4729 -- as subprogram parameters.
4735 -- Deal with delayed aspect specifications. The analysis of the aspect
4736 -- is required to be delayed to the freeze point, thus we analyze the
4737 -- pragma or attribute definition clause in the tree at this point. We
4738 -- also analyze the aspect specification node at the freeze point when
4739 -- the aspect doesn't correspond to pragma/attribute definition clause.
4745 -- Here to freeze the entity
4749 -- Case of entity being frozen is other than a type
4753 -- If entity is exported or imported and does not have an external
4754 -- name, now is the time to provide the appropriate default name.
4755 -- Skip this if the entity is stubbed, since we don't need a name
4756 -- for any stubbed routine. For the case on intrinsics, if no
4757 -- external name is specified, then calls will be handled in
4758 -- Exp_Intr.Expand_Intrinsic_Call, and no name is needed. If an
4759 -- external name is provided, then Expand_Intrinsic_Call leaves
4760 -- calls in place for expansion by GIGI.
4766 then
4767 Set_Encoded_Interface_Name
4770 -- If entity is an atomic object appearing in a declaration and
4771 -- the expression is an aggregate, assign it to a temporary to
4772 -- ensure that the actual assignment is done atomically rather
4773 -- than component-wise (the assignment to the temp may be done
4774 -- component-wise, but that is harmless).
4781 then
4785 -- Subprogram case
4789 -- Check for needing to wrap imported subprogram
4793 -- Freeze all parameter types and the return type (RM 13.14(14)).
4794 -- However skip this for internal subprograms. This is also where
4795 -- any extra formal parameters are created since we now know
4796 -- whether the subprogram will use a foreign convention.
4798 -- In Ada 2012, freezing a subprogram does not always freeze
4799 -- the corresponding profile (see AI05-019). An attribute
4800 -- reference is not a freezing point of the profile.
4801 -- Other constructs that should not freeze ???
4803 -- This processing doesn't apply to internal entities (see below)
4807 Restore_Globals;
4812 -- Must freeze its parent first if it is a derived subprogram
4818 -- We don't freeze internal subprograms, because we don't normally
4819 -- want addition of extra formals or mechanism setting to happen
4820 -- for those. However we do pass through predefined dispatching
4821 -- cases, since extra formals may be needed in some cases, such as
4822 -- for the stream 'Input function (build-in-place formals).
4826 then
4832 Restore_Globals;
4836 -- If warning on suspicious contracts then check for the case of
4837 -- a postcondition other than False for a No_Return subprogram.
4840 and then Warn_On_Suspicious_Contract
4842 then
4843 declare
4847 begin
4850 Name_Postcondition,
4851 Name_Refined_Post)
4852 then
4853 Exp :=
4854 Expression
4859 then
4860 Error_Msg_NE
4871 -- Here for other than a subprogram or type
4873 else
4874 -- If entity has a type, and it is not a generic unit, then
4875 -- freeze it first (RM 13.14(10)).
4879 then
4882 -- For an object of an anonymous array type, aspects on the
4883 -- object declaration apply to the type itself. This is the
4884 -- case for Atomic_Components, Volatile_Components, and
4885 -- Independent_Components. In these cases analysis of the
4886 -- generated pragma will mark the anonymous types accordingly,
4887 -- and the object itself does not require a freeze node.
4893 then
4900 -- Special processing for objects created by object declaration
4906 -- Check that a constant which has a pragma Volatile[_Components]
4907 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
4909 -- Note: Atomic[_Components] also sets Volatile[_Components]
4915 then
4916 -- Make sure we actually have a pragma, and have not merely
4917 -- inherited the indication from elsewhere (e.g. an address
4918 -- clause, which is not good enough in RM terms).
4921 or else
4923 then
4924 Error_Msg_N
4929 or else
4931 then
4932 Error_Msg_N
4938 -- Static objects require special handling
4942 then
4946 -- Remaining step is to layout objects
4950 then
4954 -- For an object that does not have delayed freezing, and whose
4955 -- initialization actions have been captured in a compound
4956 -- statement, move them back now directly within the enclosing
4957 -- statement sequence.
4961 then
4966 -- Case of a type or subtype being frozen
4968 else
4969 -- We used to check here that a full type must have preelaborable
4970 -- initialization if it completes a private type specified with
4971 -- pragma Preelaborable_Initialization, but that missed cases where
4972 -- the types occur within a generic package, since the freezing
4973 -- that occurs within a containing scope generally skips traversal
4974 -- of a generic unit's declarations (those will be frozen within
4975 -- instances). This check was moved to Analyze_Package_Specification.
4977 -- The type may be defined in a generic unit. This can occur when
4978 -- freezing a generic function that returns the type (which is
4979 -- defined in a parent unit). It is clearly meaningless to freeze
4980 -- this type. However, if it is a subtype, its size may be determi-
4981 -- nable and used in subsequent checks, so might as well try to
4982 -- compute it.
4984 -- In Ada 2012, Freeze_Entities is also used in the front end to
4985 -- trigger the analysis of aspect expressions, so in this case we
4986 -- want to continue the freezing process.
4990 and then
4993 then
4995 Restore_Globals;
4999 -- Check for error of Type_Invariant'Class applied to an untagged
5000 -- type (check delayed to freeze time when full type is available).
5002 declare
5004 begin
5008 then
5009 Error_Msg_NE
5012 Error_Msg_N
5017 -- A Ghost type cannot be effectively volatile (SPARK RM 6.9(8))
5021 then
5025 -- Deal with special cases of freezing for subtype
5029 -- Before we do anything else, a specialized test for the case of
5030 -- a size given for an array where the array needs to be packed,
5031 -- but was not so the size cannot be honored. This is the case
5032 -- where implicit packing may apply. The reason we do this so
5033 -- early is that if we have implicit packing, the layout of the
5034 -- base type is affected, so we must do this before we freeze
5035 -- the base type.
5037 -- We could do this processing only if implicit packing is enabled
5038 -- since in all other cases, the error would be caught by the back
5039 -- end. However, we choose to do the check even if we do not have
5040 -- implicit packing enabled, since this allows us to give a more
5041 -- useful error message (advising use of pragmas Implicit_Packing
5042 -- or Pack).
5045 declare
5056 -- Number of elements in array
5058 begin
5059 -- Check enabling conditions. These are straightforward
5060 -- except for the test for a limited composite type. This
5061 -- eliminates the rare case of a array of limited components
5062 -- where there are issues of whether or not we can go ahead
5063 -- and pack the array (since we can't freely pack and unpack
5064 -- arrays if they are limited).
5066 -- Note that we check the root type explicitly because the
5067 -- whole point is we are doing this test before we have had
5068 -- a chance to freeze the base type (and it is that freeze
5069 -- action that causes stuff to be inherited).
5082 then
5083 -- Compute number of elements in array
5091 and then
5093 then
5097 Num_Elmts :=
5098 Num_Elmts *
5104 -- What we are looking for here is the situation where
5105 -- the RM_Size given would be exactly right if there was
5106 -- a pragma Pack (resulting in the component size being
5107 -- the same as the RM_Size). Furthermore, the component
5108 -- type size must be an odd size (not a multiple of
5109 -- storage unit). If the component RM size is an exact
5110 -- number of storage units that is a power of two, the
5111 -- array is not packed and has a standard representation.
5115 then
5116 -- For implicit packing mode, just set the component
5117 -- size silently.
5125 -- Otherwise give an error message
5127 else
5128 Error_Msg_NE
5130 Error_Msg_N -- CODEFIX
5136 and then Implicit_Packing
5137 and then
5139 or else
5141 or else
5143 then
5144 -- Not a packed array, but indicate the desired
5145 -- component size, for the back-end.
5155 -- If ancestor subtype present, freeze that first. Note that this
5156 -- will also get the base type frozen. Need RM reference ???
5163 -- No ancestor subtype present
5165 else
5166 -- See if we have a nearest ancestor that has a predicate.
5167 -- That catches the case of derived type with a predicate.
5168 -- Need RM reference here ???
5176 -- Freeze base type before freezing the entity (RM 13.14(15))
5183 -- A subtype inherits all the type-related representation aspects
5184 -- from its parents (RM 13.1(8)).
5188 -- For a derived type, freeze its parent type first (RM 13.14(15))
5194 -- A derived type inherits each type-related representation aspect
5195 -- of its parent type that was directly specified before the
5196 -- declaration of the derived type (RM 13.1(15)).
5201 -- Check for incompatible size and alignment for record type
5203 if Warn_On_Size_Alignment
5207 -- If explicit Object_Size clause given assume that the programmer
5208 -- knows what he is doing, and expects the compiler behavior.
5212 -- Check for size not a multiple of alignment
5215 then
5216 declare
5222 begin
5225 -- Give a warning
5229 Error_Msg_NE
5235 else
5237 Error_Msg_NE
5250 -- Array type
5255 -- For a class-wide type, the corresponding specific type is
5256 -- frozen as well (RM 13.14(15))
5261 -- If the base type of the class-wide type is still incomplete,
5262 -- the class-wide remains unfrozen as well. This is legal when
5263 -- E is the formal of a primitive operation of some other type
5264 -- which is being frozen.
5268 Restore_Globals;
5272 -- The equivalent type associated with a class-wide subtype needs
5273 -- to be frozen to ensure that its layout is done.
5277 then
5281 -- Generate an itype reference for a library-level class-wide type
5282 -- at the freeze point. Otherwise the first explicit reference to
5283 -- the type may appear in an inner scope which will be rejected by
5284 -- the back-end.
5288 then
5289 declare
5292 begin
5295 -- From a gigi point of view, a class-wide subtype derives
5296 -- from its record equivalent type. As a result, the itype
5297 -- reference must appear after the freeze node of the
5298 -- equivalent type or gigi will reject the reference.
5302 then
5304 else
5310 -- For a record type or record subtype, freeze all component types
5311 -- (RM 13.14(15)). We test for E_Record_(sub)Type here, rather than
5312 -- using Is_Record_Type, because we don't want to attempt the freeze
5313 -- for the case of a private type with record extension (we will do
5314 -- that later when the full type is frozen).
5319 then
5322 -- For a concurrent type, freeze corresponding record type. This does
5323 -- not correspond to any specific rule in the RM, but the record type
5324 -- is essentially part of the concurrent type. Also freeze all local
5325 -- entities. This includes record types created for entry parameter
5326 -- blocks and whatever local entities may appear in the private part.
5340 -- The guard on the presence of the Etype seems to be needed
5341 -- for some CodePeer (-gnatcC) cases, but not clear why???
5346 then
5357 -- Private types are required to point to the same freeze node as
5358 -- their corresponding full views. The freeze node itself has to
5359 -- point to the partial view of the entity (because from the partial
5360 -- view, we can retrieve the full view, but not the reverse).
5361 -- However, in order to freeze correctly, we need to freeze the full
5362 -- view. If we are freezing at the end of a scope (or within the
5363 -- scope) of the private type, the partial and full views will have
5364 -- been swapped, the full view appears first in the entity chain and
5365 -- the swapping mechanism ensures that the pointers are properly set
5366 -- (on scope exit).
5368 -- If we encounter the partial view before the full view (e.g. when
5369 -- freezing from another scope), we freeze the full view, and then
5370 -- set the pointers appropriately since we cannot rely on swapping to
5371 -- fix things up (subtypes in an outer scope might not get swapped).
5373 -- If the full view is itself private, the above requirements apply
5374 -- to the underlying full view instead of the full view. But there is
5375 -- no swapping mechanism for the underlying full view so we need to
5376 -- set the pointers appropriately in both cases.
5380 then
5381 -- The construction of the dispatch table associated with library
5382 -- level tagged types forces freezing of all the primitives of the
5383 -- type, which may cause premature freezing of the partial view.
5384 -- For example:
5386 -- package Pkg is
5387 -- type T is tagged private;
5388 -- type DT is new T with private;
5389 -- procedure Prim (X : in out T; Y : in out DT'Class);
5390 -- private
5391 -- type T is tagged null record;
5392 -- Obj : T;
5393 -- type DT is new T with null record;
5394 -- end;
5396 -- In this case the type will be frozen later by the usual
5397 -- mechanism: an object declaration, an instantiation, or the
5398 -- end of a declarative part.
5402 then
5404 Restore_Globals;
5407 -- Case of full view present
5411 -- If full view has already been frozen, then no further
5412 -- processing is required
5418 -- Otherwise freeze full view and patch the pointers so that
5419 -- the freeze node will elaborate both views in the back end.
5420 -- However, if full view is itself private, freeze underlying
5421 -- full view instead and patch the pointers so that the freeze
5422 -- node will elaborate the three views in the back end.
5424 else
5425 declare
5428 begin
5431 then
5439 then
5446 else
5459 else
5460 -- {Incomplete,Private}_Subtypes with Full_Views
5461 -- constrained by discriminants.
5472 -- AI-117 requires that the convention of a partial view be the
5473 -- same as the convention of the full view. Note that this is a
5474 -- recognized breach of privacy, but it's essential for logical
5475 -- consistency of representation, and the lack of a rule in
5476 -- RM95 was an oversight.
5483 -- Size information is copied from the full view to the
5484 -- incomplete or private view for consistency.
5486 -- We skip this is the full view is not a type. This is very
5487 -- strange of course, and can only happen as a result of
5488 -- certain illegalities, such as a premature attempt to derive
5489 -- from an incomplete type.
5496 Restore_Globals;
5499 -- Case of underlying full view present
5503 then
5508 -- Patch the pointers so that the freeze node will elaborate
5509 -- both views in the back end.
5518 else
5526 Restore_Globals;
5529 -- Case of no full view present. If entity is derived or subtype,
5530 -- it is safe to freeze, correctness depends on the frozen status
5531 -- of parent. Otherwise it is either premature usage, or a Taft
5532 -- amendment type, so diagnosis is at the point of use and the
5533 -- type might be frozen later.
5538 else
5540 Restore_Globals;
5544 -- For access subprogram, freeze types of all formals, the return
5545 -- type was already frozen, since it is the Etype of the function.
5546 -- Formal types can be tagged Taft amendment types, but otherwise
5547 -- they cannot be incomplete.
5555 then
5559 -- AI05-151: Incomplete types are allowed in access to
5560 -- subprogram specifications.
5563 Error_Msg_NE
5574 -- For access to a protected subprogram, freeze the equivalent type
5575 -- (however this is not set if we are not generating code or if this
5576 -- is an anonymous type used just for resolution).
5584 -- Generic types are never seen by the back-end, and are also not
5585 -- processed by the expander (since the expander is turned off for
5586 -- generic processing), so we never need freeze nodes for them.
5589 Restore_Globals;
5593 -- Some special processing for non-generic types to complete
5594 -- representation details not known till the freeze point.
5599 -- Some error checks required for ordinary fixed-point type. Defer
5600 -- these till the freeze-point since we need the small and range
5601 -- values. We only do these checks for base types
5606 Error_Msg_N
5611 Error_Msg_N
5617 Error_Msg_N
5623 Error_Msg_N
5635 and then Warn_On_Suspicious_Modulus_Value
5636 then
5640 -- The pool applies to named and anonymous access types, but not
5641 -- to subprogram and to internal types generated for 'Access
5642 -- references.
5647 then
5648 -- If a pragma Default_Storage_Pool applies, and this type has no
5649 -- Storage_Pool or Storage_Size clause (which must have occurred
5650 -- before the freezing point), then use the default. This applies
5651 -- only to base types.
5653 -- None of this applies to access to subprograms, for which there
5654 -- are clearly no pools.
5660 then
5661 -- Case of pragma Default_Storage_Pool (null)
5666 -- Case of pragma Default_Storage_Pool (storage_pool_NAME)
5668 else
5673 -- Check restriction for standard storage pool
5679 -- Deal with error message for pure access type. This is not an
5680 -- error in Ada 2005 if there is no pool (see AI-366).
5686 then
5690 Error_Msg_N
5694 Error_Msg_N
5697 else
5698 Error_Msg_N
5705 -- Case of composite types
5709 -- AI-117 requires that all new primitives of a tagged type must
5710 -- inherit the convention of the full view of the type. Inherited
5711 -- and overriding operations are defined to inherit the convention
5712 -- of their parent or overridden subprogram (also specified in
5713 -- AI-117), which will have occurred earlier (in Derive_Subprogram
5714 -- and New_Overloaded_Entity). Here we set the convention of
5715 -- primitives that are still convention Ada, which will ensure
5716 -- that any new primitives inherit the type's convention. Class-
5717 -- wide types can have a foreign convention inherited from their
5718 -- specific type, but are excluded from this since they don't have
5719 -- any associated primitives.
5724 then
5725 declare
5729 begin
5741 -- If the type is a simple storage pool type, then this is where
5742 -- we attempt to locate and validate its Allocate, Deallocate, and
5743 -- Storage_Size operations (the first is required, and the latter
5744 -- two are optional). We also verify that the full type for a
5745 -- private type is allowed to be a simple storage pool type.
5749 then
5750 -- If the type is marked Has_Private_Declaration, then this is
5751 -- a full type for a private type that was specified with the
5752 -- pragma Simple_Storage_Pool_Type, and here we ensure that the
5753 -- pragma is allowed for the full type (for example, it can't
5754 -- be an array type, or a nonlimited record type).
5759 then
5761 Error_Msg_N
5772 procedure Validate_Simple_Pool_Op_Formal
5779 -- Validate one formal Pool_Op_Formal of the candidate pool
5780 -- operation Pool_Op. The formal must be of Expected_Type
5781 -- and have mode Expected_Mode. OK_Formal will be set to
5782 -- False if the formal doesn't match. If OK_Formal is False
5783 -- on entry, then the formal will effectively be ignored
5784 -- (because validation of the pool op has already failed).
5785 -- Upon return, Pool_Op_Formal will be updated to the next
5786 -- formal, if any.
5788 procedure Validate_Simple_Pool_Operation
5790 -- Search for and validate a simple pool operation with the
5791 -- name Op_Name. If the name is Allocate, then there must be
5792 -- exactly one such primitive operation for the simple pool
5793 -- type. If the name is Deallocate or Storage_Size, then
5794 -- there can be at most one such primitive operation. The
5795 -- profile of the located primitive must conform to what
5796 -- is expected for each operation.
5798 ------------------------------------
5799 -- Validate_Simple_Pool_Op_Formal --
5800 ------------------------------------
5802 procedure Validate_Simple_Pool_Op_Formal
5809 is
5810 begin
5811 -- If OK_Formal is False on entry, then simply ignore
5812 -- the formal, because an earlier formal has already
5813 -- been flagged.
5818 -- If no formal is passed in, then issue an error for a
5819 -- missing formal.
5822 Error_Msg_NE
5832 -- If the pool type was expected for this formal, then
5833 -- this will not be considered a candidate operation
5834 -- for the simple pool, so we unset OK_Formal so that
5835 -- the op and any later formals will be ignored.
5842 else
5843 Error_Msg_NE
5850 -- Issue error if formal's mode is not the expected one
5853 Error_Msg_N
5855 Pool_Op_Formal);
5858 -- Advance to the next formal
5863 ------------------------------------
5864 -- Validate_Simple_Pool_Operation --
5865 ------------------------------------
5867 procedure Validate_Simple_Pool_Operation
5869 is
5875 begin
5876 pragma Assert
5878 Name_Deallocate,
5879 Name_Storage_Size));
5883 -- For each homonym declared immediately in the scope
5884 -- of the simple storage pool type, determine whether
5885 -- the homonym is an operation of the pool type, and,
5886 -- if so, check that its profile is as expected for
5887 -- a simple pool operation of that name.
5893 then
5898 -- The first parameter must be of the pool type
5899 -- in order for the operation to qualify.
5902 Validate_Simple_Pool_Op_Formal
5905 else
5906 Validate_Simple_Pool_Op_Formal
5911 -- If another operation with this name has already
5912 -- been located for the type, then flag an error,
5913 -- since we only allow the type to have a single
5914 -- such primitive.
5917 Error_Msg_NE
5922 -- In the case of Allocate and Deallocate, a formal
5923 -- of type System.Address is required.
5926 Validate_Simple_Pool_Op_Formal
5931 Validate_Simple_Pool_Op_Formal
5936 -- In the case of Allocate and Deallocate, formals
5937 -- of type Storage_Count are required as the third
5938 -- and fourth parameters.
5941 Validate_Simple_Pool_Op_Formal
5944 Validate_Simple_Pool_Op_Formal
5949 -- If no mismatched formals have been found (Is_OK)
5950 -- and no excess formals are present, then this
5951 -- operation has been validated, so record it.
5961 -- There must be a valid Allocate operation for the type,
5962 -- so issue an error if none was found.
5966 then
5972 -- Simple pool operations can't be abstract
5975 Error_Msg_N
5980 -- The Storage_Size operation must be a function with
5981 -- Storage_Count as its result type.
5985 Error_Msg_N
5989 Error_Msg_NE
5994 -- Allocate and Deallocate must be procedures
5997 Error_Msg_N
6003 -- Start of processing for Validate_Simple_Pool_Ops
6005 begin
6013 -- Now that all types from which E may depend are frozen, see if the
6014 -- size is known at compile time, if it must be unsigned, or if
6015 -- strict alignment is required
6024 -- Do not allow a size clause for a type which does not have a size
6025 -- that is known at compile time
6029 then
6030 -- Suppress this message if errors posted on E, even if we are
6031 -- in all errors mode, since this is often a junk message
6034 Error_Msg_N
6040 -- Now we set/verify the representation information, in particular
6041 -- the size and alignment values. This processing is not required for
6042 -- generic types, since generic types do not play any part in code
6043 -- generation, and so the size and alignment values for such types
6044 -- are irrelevant. Ditto for types declared within a generic unit,
6045 -- which may have components that depend on generic parameters, and
6046 -- that will be recreated in an instance.
6051 -- Otherwise we call the layout procedure
6053 else
6057 -- If this is an access to subprogram whose designated type is itself
6058 -- a subprogram type, the return type of this anonymous subprogram
6059 -- type must be decorated as well.
6063 then
6067 -- If the type has a Defaut_Value/Default_Component_Value aspect,
6068 -- this is where we analye the expression (after the type is frozen,
6069 -- since in the case of Default_Value, we are analyzing with the
6070 -- type itself, and we treat Default_Component_Value similarly for
6071 -- the sake of uniformity).
6074 declare
6079 begin
6084 else
6095 Flag_Non_Static_Expr
6102 -- End of freeze processing for type entities
6105 -- Here is where we logically freeze the current entity. If it has a
6106 -- freeze node, then this is the point at which the freeze node is
6107 -- linked into the result list.
6111 -- If a freeze node is already allocated, use it, otherwise allocate
6112 -- a new one. The preallocation happens in the case of anonymous base
6113 -- types, where we preallocate so that we can set First_Subtype_Link.
6114 -- Note that we reset the Sloc to the current freeze location.
6120 else
6131 -- A final pass over record types with discriminants. If the type
6132 -- has an incomplete declaration, there may be constrained access
6133 -- subtypes declared elsewhere, which do not depend on the discrimi-
6134 -- nants of the type, and which are used as component types (i.e.
6135 -- the full view is a recursive type). The designated types of these
6136 -- subtypes can only be elaborated after the type itself, and they
6137 -- need an itype reference.
6141 then
6142 declare
6147 begin
6157 then
6169 -- When a type is frozen, the first subtype of the type is frozen as
6170 -- well (RM 13.14(15)). This has to be done after freezing the type,
6171 -- since obviously the first subtype depends on its own base type.
6176 -- If we just froze a tagged non-class wide record, then freeze the
6177 -- corresponding class-wide type. This must be done after the tagged
6178 -- type itself is frozen, because the class-wide type refers to the
6179 -- tagged type which generates the class.
6184 then
6191 -- Special handling for subprograms
6195 -- If subprogram has address clause then reset Is_Public flag, since
6196 -- we do not want the backend to generate external references.
6200 then
6205 Restore_Globals;
6209 -----------------------------
6210 -- Freeze_Enumeration_Type --
6211 -----------------------------
6214 begin
6215 -- By default, if no size clause is present, an enumeration type with
6216 -- Convention C is assumed to interface to a C enum, and has integer
6217 -- size. This applies to types. For subtypes, verify that its base
6218 -- type has no size clause either. Treat other foreign conventions
6219 -- in the same way, and also make sure alignment is set right.
6226 -- Don't do this if Short_Enums on target
6228 and then not Target_Short_Enums
6229 then
6233 -- Normal Ada case or size clause present or not Long_C_Enums on target
6235 else
6236 -- If the enumeration type interfaces to C, and it has a size clause
6237 -- that specifies less than int size, it warrants a warning. The
6238 -- user may intend the C type to be an enum or a char, so this is
6239 -- not by itself an error that the Ada compiler can detect, but it
6240 -- it is a worth a heads-up. For Boolean and Character types we
6241 -- assume that the programmer has the proper C type in mind.
6249 -- Don't do this if Short_Enums on target
6251 and then not Target_Short_Enums
6252 then
6253 Error_Msg_N
6261 -----------------------
6262 -- Freeze_Expression --
6263 -----------------------
6274 -- This flag is set true if the entity must be frozen outside the
6275 -- current subprogram. This happens in the case of expander generated
6276 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
6277 -- not freeze all entities like other bodies, but which nevertheless
6278 -- may reference entities that have to be frozen before the body and
6279 -- obviously cannot be frozen inside the body.
6282 -- If the expression is an array aggregate, the type of the component
6283 -- expressions is also frozen. If the component type is an access type
6284 -- and the expressions include allocators, the designed type is frozen
6285 -- as well.
6288 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
6289 -- it is the handled statement sequence of an expander-generated
6290 -- subprogram (init proc, stream subprogram, or renaming as body).
6291 -- If so, this is not a freezing context.
6293 -----------------------------------------
6294 -- Find_Aggregate_Component_Desig_Type --
6295 -----------------------------------------
6301 begin
6327 ----------------------
6328 -- In_Expanded_Body --
6329 ----------------------
6335 begin
6338 else
6345 else
6348 -- The following are expander-created bodies, or bodies that
6349 -- are not freeze points.
6358 N_Subprogram_Renaming_Declaration,
6359 N_Expression_Function))
6360 then
6362 else
6368 -- Start of processing for Freeze_Expression
6370 begin
6371 -- Immediate return if freezing is inhibited. This flag is set by the
6372 -- analyzer to stop freezing on generated expressions that would cause
6373 -- freezing if they were in the source program, but which are not
6374 -- supposed to freeze, since they are created.
6380 -- If expression is non-static, then it does not freeze in a default
6381 -- expression, see section "Handling of Default Expressions" in the
6382 -- spec of package Sem for further details. Note that we have to make
6383 -- sure that we actually have a real expression (if we have a subtype
6384 -- indication, we can't test Is_OK_Static_Expression). However, we
6385 -- exclude the case of the prefix of an attribute of a static scalar
6386 -- subtype from this early return, because static subtype attributes
6387 -- should always cause freezing, even in default expressions, but
6388 -- the attribute may not have been marked as static yet (because in
6389 -- Resolve_Attribute, the call to Eval_Attribute follows the call of
6390 -- Freeze_Expression on the prefix).
6392 if In_Spec_Exp
6399 then
6403 -- Freeze type of expression if not frozen already
6411 -- Base type may be an derived numeric type that is frozen at
6412 -- the point of declaration, but first_subtype is still unfrozen.
6419 -- For entity name, freeze entity if not frozen already. A special
6420 -- exception occurs for an identifier that did not come from source.
6421 -- We don't let such identifiers freeze a non-internal entity, i.e.
6422 -- an entity that did come from source, since such an identifier was
6423 -- generated by the expander, and cannot have any semantic effect on
6424 -- the freezing semantics. For example, this stops the parameter of
6425 -- an initialization procedure from freezing the variable.
6432 then
6439 else
6443 -- For an allocator freeze designated type if not frozen already
6445 -- For an aggregate whose component type is an access type, freeze the
6446 -- designated type now, so that its freeze does not appear within the
6447 -- loop that might be created in the expansion of the aggregate. If the
6448 -- designated type is a private type without full view, the expression
6449 -- cannot contain an allocator, so the type is not frozen.
6451 -- For a function, we freeze the entity when the subprogram declaration
6452 -- is frozen, but a function call may appear in an initialization proc.
6453 -- before the declaration is frozen. We need to generate the extra
6454 -- formals, if any, to ensure that the expansion of the call includes
6455 -- the proper actuals. This only applies to Ada subprograms, not to
6456 -- imported ones.
6467 then
6469 -- Check whether aggregate includes allocators.
6474 when N_Selected_Component |
6475 N_Indexed_Component |
6476 N_Slice =>
6487 then
6498 then
6502 -- All done if nothing needs freezing
6507 then
6511 -- Examine the enclosing context by climbing the parent chain. The
6512 -- traversal serves two purposes - to detect scenarios where freezeing
6513 -- is not needed and to find the proper insertion point for the freeze
6514 -- nodes. Although somewhat similar to Insert_Actions, this traversal
6515 -- is freezing semantics-sensitive. Inserting freeze nodes blindly in
6516 -- the tree may result in types being frozen too early.
6519 loop
6522 -- If we don't have a parent, then we are not in a well-formed tree.
6523 -- This is an unusual case, but there are some legitimate situations
6524 -- in which this occurs, notably when the expressions in the range of
6525 -- a type declaration are resolved. We simply ignore the freeze
6526 -- request in this case. Is this right ???
6532 -- See if we have got to an appropriate point in the tree
6536 -- A special test for the exception of (RM 13.14(8)) for the case
6537 -- of per-object expressions (RM 3.8(18)) occurring in component
6538 -- definition or a discrete subtype definition. Note that we test
6539 -- for a component declaration which includes both cases we are
6540 -- interested in, and furthermore the tree does not have explicit
6541 -- nodes for either of these two constructs.
6545 -- The case we want to test for here is an identifier that is
6546 -- a per-object expression, this is either a discriminant that
6547 -- appears in a context other than the component declaration
6548 -- or it is a reference to the type of the enclosing construct.
6550 -- For either of these cases, we skip the freezing
6552 if not In_Spec_Expression
6555 then
6556 -- We recognize the discriminant case by just looking for
6557 -- a reference to a discriminant. It can only be one for
6558 -- the enclosing construct. Skip freezing in this case.
6563 -- For the case of a reference to the enclosing record,
6564 -- (or task or protected type), we look for a type that
6565 -- matches the current scope.
6572 -- If we have an enumeration literal that appears as the choice in
6573 -- the aggregate of an enumeration representation clause, then
6574 -- freezing does not occur (RM 13.14(10)).
6578 -- The case we are looking for is an enumeration literal
6582 then
6583 -- If enumeration literal appears directly as the choice,
6584 -- do not freeze (this is the normal non-overloaded case)
6588 then
6591 -- If enumeration literal appears as the name of function
6592 -- which is the choice, then also do not freeze. This
6593 -- happens in the overloaded literal case, where the
6594 -- enumeration literal is temporarily changed to a function
6595 -- call for overloading analysis purposes.
6598 and then
6600 and then
6602 then
6607 -- Normally if the parent is a handled sequence of statements,
6608 -- then the current node must be a statement, and that is an
6609 -- appropriate place to insert a freeze node.
6613 -- An exception occurs when the sequence of statements is for
6614 -- an expander generated body that did not do the usual freeze
6615 -- all operation. In this case we usually want to freeze
6616 -- outside this body, not inside it, and we skip past the
6617 -- subprogram body that we are inside.
6620 declare
6624 begin
6625 -- Freeze the entity only when it is declared inside the
6626 -- body of the expander generated procedure. This case
6627 -- is recognized by the scope of the entity or its type,
6628 -- which is either the spec for some enclosing body, or
6629 -- (in the case of init_procs, for which there are no
6630 -- separate specs) the current scope.
6636 or else
6638 then
6644 then
6649 -- An expression function may act as a completion of
6650 -- a function declaration. As such, it can reference
6651 -- entities declared between the two views:
6653 -- Hidden []; -- 1
6654 -- function F return ...;
6655 -- private
6656 -- function Hidden return ...;
6657 -- function F return ... is (Hidden); -- 2
6659 -- Refering to the example above, freezing the expression
6660 -- of F (2) would place Hidden's freeze node (1) in the
6661 -- wrong place. Avoid explicit freezing and let the usual
6662 -- scenarios do the job - for example, reaching the end
6663 -- of the private declarations, or a call to F.
6666 N_Expression_Function
6667 then
6670 -- Freeze outside the body
6672 else
6678 -- Here if normal case where we are in handled statement
6679 -- sequence and want to do the insertion right there.
6681 else
6685 -- If parent is a body or a spec or a block, then the current node
6686 -- is a statement or declaration and we can insert the freeze node
6687 -- before it.
6689 when N_Block_Statement |
6690 N_Entry_Body |
6691 N_Package_Body |
6692 N_Package_Specification |
6693 N_Protected_Body |
6694 N_Subprogram_Body |
6697 -- The expander is allowed to define types in any statements list,
6698 -- so any of the following parent nodes also mark a freezing point
6699 -- if the actual node is in a list of statements or declarations.
6701 when N_Abortable_Part |
6702 N_Accept_Alternative |
6703 N_And_Then |
6704 N_Case_Statement_Alternative |
6705 N_Compilation_Unit_Aux |
6706 N_Conditional_Entry_Call |
6707 N_Delay_Alternative |
6708 N_Elsif_Part |
6709 N_Entry_Call_Alternative |
6710 N_Exception_Handler |
6711 N_Extended_Return_Statement |
6712 N_Freeze_Entity |
6713 N_If_Statement |
6714 N_Or_Else |
6715 N_Selective_Accept |
6716 N_Triggering_Alternative =>
6720 -- Freeze nodes produced by an expression coming from the Actions
6721 -- list of a N_Expression_With_Actions node must remain within the
6722 -- Actions list. Inserting the freeze nodes further up the tree
6723 -- may lead to use before declaration issues in the case of array
6724 -- types.
6729 then
6733 -- Note: N_Loop_Statement is a special case. A type that appears
6734 -- in the source can never be frozen in a loop (this occurs only
6735 -- because of a loop expanded by the expander), so we keep on
6736 -- going. Otherwise we terminate the search. Same is true of any
6737 -- entity which comes from source. (if they have predefined type,
6738 -- that type does not appear to come from source, but the entity
6739 -- should not be frozen here).
6745 -- For all other cases, keep looking at parents
6751 -- We fall through the case if we did not yet find the proper
6752 -- place in the free for inserting the freeze node, so climb.
6757 -- If the expression appears in a record or an initialization procedure,
6758 -- the freeze nodes are collected and attached to the current scope, to
6759 -- be inserted and analyzed on exit from the scope, to insure that
6760 -- generated entities appear in the correct scope. If the expression is
6761 -- a default for a discriminant specification, the scope is still void.
6762 -- The expression can also appear in the discriminant part of a private
6763 -- or concurrent type.
6765 -- If the expression appears in a constrained subcomponent of an
6766 -- enclosing record declaration, the freeze nodes must be attached to
6767 -- the outer record type so they can eventually be placed in the
6768 -- enclosing declaration list.
6770 -- The other case requiring this special handling is if we are in a
6771 -- default expression, since in that case we are about to freeze a
6772 -- static type, and the freeze scope needs to be the outer scope, not
6773 -- the scope of the subprogram with the default parameter.
6775 -- For default expressions and other spec expressions in generic units,
6776 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
6777 -- placing them at the proper place, after the generic unit.
6780 or else Freeze_Outside
6785 then
6786 declare
6791 begin
6804 -- The current scope may be that of a constrained component of
6805 -- an enclosing record declaration, or of a loop of an enclosing
6806 -- quantified expression, which is above the current scope in the
6807 -- scope stack. Indeed in the context of a quantified expression,
6808 -- a scope is created and pushed above the current scope in order
6809 -- to emulate the loop-like behavior of the quantified expression.
6810 -- If the expression is within a top-level pragma, as for a pre-
6811 -- condition on a library-level subprogram, nothing to do.
6816 N_Quantified_Expression)
6817 then
6824 Freeze_Nodes;
6825 else
6835 -- Now we have the right place to do the freezing. First, a special
6836 -- adjustment, if we are in spec-expression analysis mode, these freeze
6837 -- actions must not be thrown away (normally all inserted actions are
6838 -- thrown away in this mode. However, the freeze actions are from static
6839 -- expressions and one of the important reasons we are doing this
6840 -- special analysis is to get these freeze actions. Therefore we turn
6841 -- off the In_Spec_Expression mode to propagate these freeze actions.
6842 -- This also means they get properly analyzed and expanded.
6846 -- Freeze the designated type of an allocator (RM 13.14(13))
6852 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
6853 -- the enumeration representation clause exception in the loop above.
6859 -- Freeze name if one is present (RM 13.14(11))
6865 -- Restore In_Spec_Expression flag
6870 -----------------------------
6871 -- Freeze_Fixed_Point_Type --
6872 -----------------------------
6874 -- Certain fixed-point types and subtypes, including implicit base types
6875 -- and declared first subtypes, have not yet set up a range. This is
6876 -- because the range cannot be set until the Small and Size values are
6877 -- known, and these are not known till the type is frozen.
6879 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
6880 -- whose bounds are unanalyzed real literals. This routine will recognize
6881 -- this case, and transform this range node into a properly typed range
6882 -- with properly analyzed and resolved values.
6899 -- Save original bounds (for shaving tests)
6902 -- Actual size chosen
6905 -- Returns size of type with given bounds. Also leaves these
6906 -- bounds set as the current bounds of the Typ.
6908 -----------
6909 -- Fsize --
6910 -----------
6913 begin
6919 -- Start of processing for Freeze_Fixed_Point_Type
6921 begin
6922 -- If Esize of a subtype has not previously been set, set it now
6929 else
6934 -- Immediate return if the range is already analyzed. This means that
6935 -- the range is already set, and does not need to be computed by this
6936 -- routine.
6942 -- Immediate return if either of the bounds raises Constraint_Error
6946 then
6956 -- Ordinary fixed-point case
6960 -- For the ordinary fixed-point case, we are allowed to fudge the
6961 -- end-points up or down by small. Generally we prefer to fudge up,
6962 -- i.e. widen the bounds for non-model numbers so that the end points
6963 -- are included. However there are cases in which this cannot be
6964 -- done, and indeed cases in which we may need to narrow the bounds.
6965 -- The following circuit makes the decision.
6967 -- Note: our terminology here is that Incl_EP means that the bounds
6968 -- are widened by Small if necessary to include the end points, and
6969 -- Excl_EP means that the bounds are narrowed by Small to exclude the
6970 -- end-points if this reduces the size.
6972 -- Note that in the Incl case, all we care about is including the
6973 -- end-points. In the Excl case, we want to narrow the bounds as
6974 -- much as permitted by the RM, to give the smallest possible size.
6991 begin
6992 -- First step. Base types are required to be symmetrical. Right
6993 -- now, the base type range is a copy of the first subtype range.
6994 -- This will be corrected before we are done, but right away we
6995 -- need to deal with the case where both bounds are non-negative.
6996 -- In this case, we set the low bound to the negative of the high
6997 -- bound, to make sure that the size is computed to include the
6998 -- required sign. Note that we do not need to worry about the
6999 -- case of both bounds negative, because the sign will be dealt
7000 -- with anyway. Furthermore we can't just go making such a bound
7001 -- symmetrical, since in a twos-complement system, there is an
7002 -- extra negative value which could not be accommodated on the
7003 -- positive side.
7008 then
7013 -- Compute the fudged bounds. If the number is a model number,
7014 -- then we do nothing to include it, but we are allowed to backoff
7015 -- to the next adjacent model number when we exclude it. If it is
7016 -- not a model number then we straddle the two values with the
7017 -- model numbers on either side.
7023 else
7027 -- The low value excluding the end point is Small greater, but
7028 -- we do not do this exclusion if the low value is positive,
7029 -- since it can't help the size and could actually hurt by
7030 -- crossing the high bound.
7035 -- If the value went from negative to zero, then we have the
7036 -- case where Loval_Incl_EP is the model number just below
7037 -- zero, so we want to stick to the negative value for the
7038 -- base type to maintain the condition that the size will
7039 -- include signed values.
7043 then
7047 else
7051 -- Similar processing for upper bound and high value
7057 else
7063 else
7067 -- One further adjustment is needed. In the case of subtypes, we
7068 -- cannot go outside the range of the base type, or we get
7069 -- peculiarities, and the base type range is already set. This
7070 -- only applies to the Incl values, since clearly the Excl values
7071 -- are already as restricted as they are allowed to be.
7078 -- Get size including and excluding end points
7083 -- No need to exclude end-points if it does not reduce size
7093 -- Now we set the actual size to be used. We want to use the
7094 -- bounds fudged up to include the end-points but only if this
7095 -- can be done without violating a specifically given size
7096 -- size clause or causing an unacceptable increase in size.
7098 -- Case of size clause given
7102 -- Use the inclusive size only if it is consistent with
7103 -- the explicitly specified size.
7110 -- If the inclusive size is too large, we try excluding
7111 -- the end-points (will be caught later if does not work).
7113 else
7119 -- Case of size clause not given
7121 else
7122 -- If we have a base type whose corresponding first subtype
7123 -- has an explicit size that is large enough to include our
7124 -- end-points, then do so. There is no point in working hard
7125 -- to get a base type whose size is smaller than the specified
7126 -- size of the first subtype.
7132 then
7137 -- If excluding the end-points makes the size smaller and
7138 -- results in a size of 8,16,32,64, then we take the smaller
7139 -- size. For the 64 case, this is compulsory. For the other
7140 -- cases, it seems reasonable. We like to include end points
7141 -- if we can, but not at the expense of moving to the next
7142 -- natural boundary of size.
7146 then
7151 -- Otherwise we can definitely include the end points
7153 else
7159 -- One pathological case: normally we never fudge a low bound
7160 -- down, since it would seem to increase the size (if it has
7161 -- any effect), but for ranges containing single value, or no
7162 -- values, the high bound can be small too large. Consider:
7164 -- type t is delta 2.0**(-14)
7165 -- range 131072.0 .. 0;
7167 -- That lower bound is *just* outside the range of 32 bits, and
7168 -- does need fudging down in this case. Note that the bounds
7169 -- will always have crossed here, since the high bound will be
7170 -- fudged down if necessary, as in the case of:
7172 -- type t is delta 2.0**(-14)
7173 -- range 131072.0 .. 131072.0;
7175 -- So we detect the situation by looking for crossed bounds,
7176 -- and if the bounds are crossed, and the low bound is greater
7177 -- than zero, we will always back it off by small, since this
7178 -- is completely harmless.
7185 -- And of course, we need to do exactly the same parallel
7186 -- fudge for flat ranges in the negative region.
7199 -- For the decimal case, none of this fudging is required, since there
7200 -- are no end-point problems in the decimal case (the end-points are
7201 -- always included).
7203 else
7207 -- At this stage, the actual size has been calculated and the proper
7208 -- required bounds are stored in the low and high bounds.
7212 Error_Msg_N
7214 Typ);
7218 -- Check size against explicit given size
7224 Error_Msg_NE
7228 else
7232 -- Increase size to next natural boundary if no size clause given
7234 else
7241 else
7249 -- If we have a base type, then expand the bounds so that they extend to
7250 -- the full width of the allocated size in bits, to avoid junk range
7251 -- checks on intermediate computations.
7258 -- Final step is to reanalyze the bounds using the proper type
7259 -- and set the Corresponding_Integer_Value fields of the literals.
7265 -- Resolve with universal fixed if the base type, and the base type if
7266 -- it is a subtype. Note we can't resolve the base type with itself,
7267 -- that would be a reference before definition.
7271 else
7275 -- Set corresponding integer value for bound
7277 Set_Corresponding_Integer_Value
7280 -- Similar processing for high bound
7288 else
7292 Set_Corresponding_Integer_Value
7295 -- Set type of range to correspond to bounds
7299 -- Set Esize to calculated size if not set already
7305 -- Set RM_Size if not already set. If already set, check value
7307 declare
7310 begin
7315 Error_Msg_NE
7320 else
7325 -- Check for shaving
7329 Error_Msg_N
7331 Error_Msg_N
7336 Error_Msg_N
7338 Error_Msg_N
7344 ------------------
7345 -- Freeze_Itype --
7346 ------------------
7351 begin
7360 --------------------------
7361 -- Freeze_Static_Object --
7362 --------------------------
7367 -- Exception raised if the type of a static object cannot be made
7368 -- static. This happens if the type depends on non-global objects.
7371 -- Called to ensure that an expression used as part of a type definition
7372 -- is statically allocatable, which means that the expression type is
7373 -- statically allocatable, and the expression is either static, or a
7374 -- reference to a library level constant.
7377 -- Called to mark a type as static, checking that it is possible
7378 -- to set the type as static. If it is not possible, then the
7379 -- exception Cannot_Be_Static is raised.
7381 -----------------------------
7382 -- Ensure_Expression_Is_SA --
7383 -----------------------------
7388 begin
7400 then
7408 -----------------------
7409 -- Ensure_Type_Is_SA --
7410 -----------------------
7416 begin
7417 -- If type is library level, we are all set
7423 -- We are also OK if the type already marked as statically allocated,
7424 -- which means we processed it before.
7430 -- Mark type as statically allocated
7434 -- Check that it is safe to statically allocate this type
7452 declare
7456 begin
7468 else
7477 then
7496 else
7501 -- Start of processing for Freeze_Static_Object
7503 begin
7506 exception
7509 -- If the object that cannot be static is imported or exported, then
7510 -- issue an error message saying that this object cannot be imported
7511 -- or exported. If it has an address clause it is an overlay in the
7512 -- current partition and the static requirement is not relevant.
7513 -- Do not issue any error message when ignoring rep clauses.
7520 Error_Msg_N
7524 -- Otherwise must be exported, something is wrong if compiler
7525 -- is marking something as statically allocated which cannot be).
7528 Error_Msg_N
7533 -----------------------
7534 -- Freeze_Subprogram --
7535 -----------------------
7541 begin
7542 -- Subprogram may not have an address clause unless it is imported
7546 Error_Msg_N
7553 -- Reset the Pure indication on an imported subprogram unless an
7554 -- explicit Pure_Function pragma was present or the subprogram is an
7555 -- intrinsic. We do this because otherwise it is an insidious error
7556 -- to call a non-pure function from pure unit and have calls
7557 -- mysteriously optimized away. What happens here is that the Import
7558 -- can bypass the normal check to ensure that pure units call only pure
7559 -- subprograms.
7561 -- The reason for the intrinsic exception is that in general, intrinsic
7562 -- functions (such as shifts) are pure anyway. The only exceptions are
7563 -- the intrinsics in GNAT.Source_Info, and that unit is not marked Pure
7564 -- in any case, so no problem arises.
7570 then
7574 -- For non-foreign convention subprograms, this is where we create
7575 -- the extra formals (for accessibility level and constrained bit
7576 -- information). We delay this till the freeze point precisely so
7577 -- that we know the convention.
7583 -- If this is convention Ada and a Valued_Procedure, that's odd
7588 and then Warn_On_Export_Import
7589 then
7590 Error_Msg_N
7595 -- Case of foreign convention
7597 else
7600 -- For foreign conventions, warn about return of unconstrained array
7605 -- If no return type, probably some other error, e.g. a
7606 -- missing full declaration, so ignore.
7611 -- If the return type is generic, we have emitted a warning
7612 -- earlier on, and there is nothing else to check here. Specific
7613 -- instantiations may lead to erroneous behavior.
7618 -- Display warning if returning unconstrained array
7623 -- Check appropriate warning is enabled (should we check for
7624 -- Warnings (Off) on specific entities here, probably so???)
7626 and then Warn_On_Export_Import
7628 -- Exclude the VM case, since return of unconstrained arrays
7629 -- is properly handled in both the JVM and .NET cases.
7632 then
7633 Error_Msg_N
7640 -- If any of the formals for an exported foreign convention
7641 -- subprogram have defaults, then emit an appropriate warning since
7642 -- this is odd (default cannot be used from non-Ada code)
7647 if Warn_On_Export_Import
7649 then
7650 Error_Msg_N
7660 -- Pragma Inline_Always is disallowed for dispatching subprograms
7661 -- because the address of such subprograms is saved in the dispatch
7662 -- table to support dispatching calls, and dispatching calls cannot
7663 -- be inlined. This is consistent with the restriction against using
7664 -- 'Access or 'Address on an Inline_Always subprogram.
7668 then
7669 Error_Msg_N
7673 -- Because of the implicit representation of inherited predefined
7674 -- operators in the front-end, the overriding status of the operation
7675 -- may be affected when a full view of a type is analyzed, and this is
7676 -- not captured by the analysis of the corresponding type declaration.
7677 -- Therefore the correctness of a not-overriding indicator must be
7678 -- rechecked when the subprogram is frozen.
7682 then
7687 ----------------------
7688 -- Is_Fully_Defined --
7689 ----------------------
7692 begin
7701 then
7702 -- Verify that the record type has no components with private types
7703 -- without completion.
7705 declare
7708 begin
7720 -- For the designated type of an access to subprogram, all types in
7721 -- the profile must be fully defined.
7724 declare
7727 begin
7740 else
7746 ---------------------------------
7747 -- Process_Default_Expressions --
7748 ---------------------------------
7750 procedure Process_Default_Expressions
7753 is
7760 begin
7763 -- A subprogram instance and its associated anonymous subprogram share
7764 -- their signature. The default expression functions are defined in the
7765 -- wrapper packages for the anonymous subprogram, and should not be
7766 -- generated again for the instance.
7771 then
7779 -- We work with a copy of the default expression because we
7780 -- do not want to disturb the original, since this would mess
7781 -- up the conformance checking.
7785 -- The analysis of the expression may generate insert actions,
7786 -- which of course must not be executed. We wrap those actions
7787 -- in a procedure that is not called, and later on eliminated.
7788 -- The following cases have no side-effects, and are analyzed
7789 -- directly.
7793 N_Integer_Literal,
7794 N_Character_Literal,
7795 N_String_Literal,
7796 N_Real_Literal)
7800 then
7801 -- If there is no default function, we must still do a full
7802 -- analyze call on the default value, to ensure that all error
7803 -- checks are performed, e.g. those associated with static
7804 -- evaluation. Note: this branch will always be taken if the
7805 -- analyzer is turned off (but we still need the error checks).
7807 -- Note: the setting of parent here is to meet the requirement
7808 -- that we can only analyze the expression while attached to
7809 -- the tree. Really the requirement is that the parent chain
7810 -- be set, we don't actually need to be in the tree.
7815 -- Default expressions are resolved with their own type if the
7816 -- context is generic, to avoid anomalies with private types.
7820 else
7824 -- If that resolved expression will raise constraint error,
7825 -- then flag the default value as raising constraint error.
7826 -- This allows a proper error message on the calls.
7832 -- If the default is a parameterless call, we use the name of
7833 -- the called function directly, and there is no body to build.
7837 then
7840 -- Else construct and analyze the body of a wrapper procedure
7841 -- that contains an object declaration to hold the expression.
7842 -- Given that this is done only to complete the analysis, it
7843 -- simpler to build a procedure than a function which might
7844 -- involve secondary stack expansion.
7846 else
7849 Dbody :=
7851 Specification =>
7858 Object_Definition =>
7862 Handled_Statement_Sequence =>
7879 ----------------------------------------
7880 -- Set_Component_Alignment_If_Not_Set --
7881 ----------------------------------------
7884 begin
7885 -- Ignore if not base type, subtypes don't need anything
7891 -- Do not override existing representation
7902 else
7903 Set_Component_Alignment
7909 --------------------------
7910 -- Set_SSO_From_Default --
7911 --------------------------
7916 begin
7917 -- Set default SSO for an array or record base type, except in case of
7918 -- a type extension (which always inherits the SSO of its parent type).
7925 then
7926 Reversed :=
7928 or else
7933 -- For a record type, if bit order is specified explicitly,
7934 -- then do not set SSO from default if not consistent. Note that
7935 -- we do not want to look at a Bit_Order attribute definition
7936 -- for a parent: if we were to inherit Bit_Order, then both
7937 -- SSO_Set_*_By_Default flags would have been cleared already
7938 -- (by Inherit_Aspects_At_Freeze_Point).
7940 and then not
7942 and then
7945 then
7946 -- If flags cause reverse storage order, then set the result. Note
7947 -- that we would have ignored the pragma setting the non default
7948 -- storage order in any case, hence the assertion at this point.
7950 pragma Assert
7955 -- For a record type, also set reversed bit order. Note: if a bit
7956 -- order has been specified explicitly, then this is a no-op.
7965 ------------------
7966 -- Undelay_Type --
7967 ------------------
7970 begin
7974 -- Since we don't want T to have a Freeze_Node, we don't want its
7975 -- Full_View or Corresponding_Record_Type to have one either.
7977 -- ??? Fundamentally, this whole handling is unpleasant. What we really
7978 -- want is to be sure that for an Itype that's part of record R and is a
7979 -- subtype of type T, that it's frozen after the later of the freeze
7980 -- points of R and T. We have no way of doing that directly, so what we
7981 -- do is force most such Itypes to be frozen as part of freezing R via
7982 -- this procedure and only delay the ones that need to be delayed
7983 -- (mostly the designated types of access types that are defined as part
7984 -- of the record).
7990 then
7998 then
8003 ------------------
8004 -- Warn_Overlay --
8005 ------------------
8007 procedure Warn_Overlay
8011 is
8013 -- The object to which the address clause applies
8019 begin
8020 -- No warning if address clause overlay warnings are off
8026 -- No warning if there is an explicit initialization
8034 -- We only give the warning for non-imported entities of a type for
8035 -- which a non-null base init proc is defined, or for objects of access
8036 -- types with implicit null initialization, or when Normalize_Scalars
8037 -- applies and the type is scalar or a string type (the latter being
8038 -- tested for because predefined String types are initialized by inline
8039 -- code rather than by an init_proc). Note that we do not give the
8040 -- warning for Initialize_Scalars, since we suppressed initialization
8041 -- in this case. Also, do not warn if Suppress_Initialization is set.
8051 then
8054 then
8059 then
8066 then
8073 -- A function call (most likely to To_Address) is probably not an
8074 -- overlay, so skip warning. Ditto if the function call was inlined
8075 -- and transformed into an entity.
8081 -- If a pragma Import follows, we assume that it is for the current
8082 -- target of the address clause, and skip the warning. There may be
8083 -- a source pragma or an aspect that specifies import and generates
8084 -- the corresponding pragma. These will indicate that the entity is
8085 -- imported and that is checked above so that the spurious warning
8086 -- (generated when the entity is frozen) will be suppressed. The
8087 -- pragma may be attached to the aspect, so it is not yet a list
8088 -- member.
8096 then
8101 -- Otherwise give warning message
8105 Error_Msg_N
8107 Nam);
8108 else
8109 Error_Msg_N
8111 Nam);
8114 -- Add friendly warning if initialization comes from a packed array
8115 -- component.
8118 declare
8121 begin
8126 then
8130 then
8131 Error_Msg_NE
8136 else
8143 Error_Msg_N
8146 Nam);