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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- F R E E Z E --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
72 -----------------------
73 -- Local Subprograms --
74 -----------------------
77 -- Typ is a type that is being frozen. If no size clause is given,
78 -- but a default Esize has been computed, then this default Esize is
79 -- adjusted up if necessary to be consistent with a given alignment,
80 -- but never to a value greater than Long_Long_Integer'Size. This
81 -- is used for all discrete types and for fixed-point types.
83 procedure Build_And_Analyze_Renamed_Body
87 -- Build body for a renaming declaration, insert in tree and analyze
90 -- Apply legality checks to address clauses for object declarations,
91 -- at the point the object is frozen. Also ensure any initialization is
92 -- performed only after the object has been frozen.
94 procedure Check_Component_Storage_Order
99 -- For an Encl_Type that has a Scalar_Storage_Order attribute definition
100 -- clause, verify that the component type has an explicit and compatible
101 -- attribute/aspect. For arrays, Comp is Empty; for records, it is the
102 -- entity of the component under consideration. For an Encl_Type that
103 -- does not have a Scalar_Storage_Order attribute definition clause,
104 -- verify that the component also does not have such a clause.
105 -- ADC is the attribute definition clause if present (or Empty). On return,
106 -- Comp_ADC_Present is set True if the component has a Scalar_Storage_Order
107 -- attribute definition clause.
110 -- When an expression function is frozen by a use of it, the expression
111 -- itself is frozen. Check that the expression does not include references
112 -- to deferred constants without completion. We report this at the freeze
113 -- point of the function, to provide a better error message.
115 -- In most cases the expression itself is frozen by the time the function
116 -- itself is frozen, because the formals will be frozen by then. However,
117 -- Attribute references to outer types are freeze points for those types;
118 -- this routine generates the required freeze nodes for them.
121 -- E is a base type. If E is tagged or has a component that is aliased
122 -- or tagged or contains something this is aliased or tagged, set
123 -- Strict_Alignment.
127 -- If E is a fixed-point or discrete type, then all the necessary work
128 -- to freeze it is completed except for possible setting of the flag
129 -- Is_Unsigned_Type, which is done by this procedure. The call has no
130 -- effect if the entity E is not a discrete or fixed-point type.
132 procedure Freeze_And_Append
136 -- Freezes Ent using Freeze_Entity, and appends the resulting list of
137 -- nodes to Result, modifying Result from No_List if necessary. N has
138 -- the same usage as in Freeze_Entity.
141 -- Freeze enumeration type. The Esize field is set as processing
142 -- proceeds (i.e. set by default when the type is declared and then
143 -- adjusted by rep clauses. What this procedure does is to make sure
144 -- that if a foreign convention is specified, and no specific size
145 -- is given, then the size must be at least Integer'Size.
148 -- If an object is frozen which has Is_Statically_Allocated set, then
149 -- all referenced types must also be marked with this flag. This routine
150 -- is in charge of meeting this requirement for the object entity E.
153 -- Perform freezing actions for a subprogram (create extra formals,
154 -- and set proper default mechanism values). Note that this routine
155 -- is not called for internal subprograms, for which neither of these
156 -- actions is needed (or desirable, we do not want for example to have
157 -- these extra formals present in initialization procedures, where they
158 -- would serve no purpose). In this call E is either a subprogram or
159 -- a subprogram type (i.e. an access to a subprogram).
162 -- True if T is not private and has no private components, or has a full
163 -- view. Used to determine whether the designated type of an access type
164 -- should be frozen when the access type is frozen. This is done when an
165 -- allocator is frozen, or an expression that may involve attributes of
166 -- the designated type. Otherwise freezing the access type does not freeze
167 -- the designated type.
169 procedure Process_Default_Expressions
172 -- This procedure is called for each subprogram to complete processing of
173 -- default expressions at the point where all types are known to be frozen.
174 -- The expressions must be analyzed in full, to make sure that all error
175 -- processing is done (they have only been pre-analyzed). If the expression
176 -- is not an entity or literal, its analysis may generate code which must
177 -- not be executed. In that case we build a function body to hold that
178 -- code. This wrapper function serves no other purpose (it used to be
179 -- called to evaluate the default, but now the default is inlined at each
180 -- point of call).
183 -- Typ is a record or array type that is being frozen. This routine sets
184 -- the default component alignment from the scope stack values if the
185 -- alignment is otherwise not specified.
188 -- As each entity is frozen, this routine is called to deal with the
189 -- setting of Debug_Info_Needed for the entity. This flag is set if
190 -- the entity comes from source, or if we are in Debug_Generated_Code
191 -- mode or if the -gnatdV debug flag is set. However, it never sets
192 -- the flag if Debug_Info_Off is set. This procedure also ensures that
193 -- subsidiary entities have the flag set as required.
196 -- T is a record or array type that is being frozen. If it is a base type,
197 -- and if SSO_Set_Low/High_By_Default is set, then Reverse_Storage order
198 -- will be set appropriately. Note that an explicit occurrence of aspect
199 -- Scalar_Storage_Order or an explicit setting of this aspect with an
200 -- attribute definition clause occurs, then these two flags are reset in
201 -- any case, so call will have no effect.
204 -- T is a type of a component that we know to be an Itype. We don't want
205 -- this to have a Freeze_Node, so ensure it doesn't. Do the same for any
206 -- Full_View or Corresponding_Record_Type.
208 procedure Warn_Overlay
212 -- Expr is the expression for an address clause for entity Nam whose type
213 -- is Typ. If Typ has a default initialization, and there is no explicit
214 -- initialization in the source declaration, check whether the address
215 -- clause might cause overlaying of an entity, and emit a warning on the
216 -- side effect that the initialization will cause.
218 -------------------------------
219 -- Adjust_Esize_For_Alignment --
220 -------------------------------
225 begin
231 then
237 ------------------------------------
238 -- Build_And_Analyze_Renamed_Body --
239 ------------------------------------
241 procedure Build_And_Analyze_Renamed_Body
245 is
251 begin
252 -- If the renamed subprogram is intrinsic, there is no need for a
253 -- wrapper body: we set the alias that will be called and expanded which
254 -- completes the declaration. This transformation is only legal if the
255 -- renamed entity has already been elaborated.
257 -- Note that it is legal for a renaming_as_body to rename an intrinsic
258 -- subprogram, as long as the renaming occurs before the new entity
259 -- is frozen (RM 8.5.4 (5)).
263 then
265 else
271 and then
275 -- We can make the renaming entity intrinsic if the renamed function
276 -- has an interface name, or if it is one of the shift/rotate
277 -- operations known to the compiler.
279 and then
282 Name_Rotate_Right,
283 Name_Shift_Left,
284 Name_Shift_Right,
285 Name_Shift_Right_Arithmetic))
286 then
291 else
298 else
307 ------------------------
308 -- Build_Renamed_Body --
309 ------------------------
311 function Build_Renamed_Body
314 is
316 -- We use for the source location of the renamed body, the location of
317 -- the spec entity. It might seem more natural to use the location of
318 -- the renaming declaration itself, but that would be wrong, since then
319 -- the body we create would look as though it was created far too late,
320 -- and this could cause problems with elaboration order analysis,
321 -- particularly in connection with instantiations.
336 -- If the renamed entity is a primitive operation given in prefix form,
337 -- the prefix is the target object and it has to be added as the first
338 -- actual in the generated call.
340 begin
341 -- Determine the entity being renamed, which is the target of the call
342 -- statement. If the name is an explicit dereference, this is a renaming
343 -- of a subprogram type rather than a subprogram. The name itself is
344 -- fully analyzed.
355 else
362 else
368 -- If the renamed entity is a predefined operator, retain full name
369 -- to ensure its visibility.
373 then
375 else
379 else
382 and then
385 then
387 -- Retrieve the target object, to be added as a first actual
388 -- in the call.
393 else
397 -- Original name may have been overloaded, but is fully resolved now
402 -- For simple renamings, subsequent calls can be expanded directly as
403 -- calls to the renamed entity. The body must be generated in any case
404 -- for calls that may appear elsewhere. This is not done in the case
405 -- where the subprogram is an instantiation because the actual proper
406 -- body has not been built yet.
411 then
415 -- The body generated for this renaming is an internal artifact, and
416 -- does not constitute a freeze point for the called entity.
423 declare
427 begin
428 -- The controlling formal may be an access parameter, or the
429 -- actual may be an access value, so adjust accordingly.
433 then
434 Actuals := New_List
439 then
440 Actuals := New_List
444 else
452 else
463 -- If the renamed entity is an entry, inherit its profile. For other
464 -- renamings as bodies, both profiles must be subtype conformant, so it
465 -- is not necessary to replace the profile given in the declaration.
466 -- However, default values that are aggregates are rewritten when
467 -- partially analyzed, so we recover the original aggregate to insure
468 -- that subsequent conformity checking works. Similarly, if the default
469 -- expression was constant-folded, recover the original expression.
479 N_Access_Definition
480 then
488 then
499 -- If the renamed entity is a function, the generated body contains a
500 -- return statement. Otherwise, build a procedure call. If the entity is
501 -- an entry, subsequent analysis of the call will transform it into the
502 -- proper entry or protected operation call. If the renamed entity is
503 -- a character literal, return it directly.
509 then
510 Call_Node :=
512 Expression =>
518 Call_Node :=
523 Call_Node :=
527 else
528 Call_Node :=
534 -- Create entities for subprogram body and formals
547 Body_Node :=
551 Handled_Statement_Sequence =>
561 -- Link the body to the entity whose declaration it completes. If
562 -- the body is analyzed when the renamed entity is frozen, it may
563 -- be necessary to restore the proper scope (see package Exp_Ch13).
567 then
569 else
576 --------------------------
577 -- Check_Address_Clause --
578 --------------------------
589 begin
596 -- Has_Delayed_Freeze was set on E when the address clause was
597 -- analyzed, and must remain set because we want the address
598 -- clause to be elaborated only after any entity it references
599 -- has been elaborated.
602 -- If Rep_Clauses are to be ignored, remove address clause from
603 -- list attached to entity, because it may be illegal for gigi,
604 -- for example by breaking order of elaboration..
607 declare
610 begin
616 else
619 loop
629 -- And now remove the address clause
635 then
641 -- Capture initialization value at point of declaration,
642 -- and make explicit assignment legal, because object may
643 -- be a constant.
649 -- Move initialization to freeze actions (once the object has
650 -- been frozen, and the address clause alignment check has been
651 -- performed.
660 -- If the objet is tagged, check whether the tag must be
661 -- reassigned expliitly.
672 -----------------------------
673 -- Check_Compile_Time_Size --
674 -----------------------------
679 -- Sets the compile time known size (32 bits or less) in the Esize
680 -- field, of T checking for a size clause that was given which attempts
681 -- to give a smaller size, and also checking for an alignment clause.
684 -- Recursive function that does all the work
687 -- If T is a constrained subtype, its size is not known if any of its
688 -- discriminant constraints is not static and it is not a null record.
689 -- The test is conservative and doesn't check that the components are
690 -- in fact constrained by non-static discriminant values. Could be made
691 -- more precise ???
693 --------------------
694 -- Set_Small_Size --
695 --------------------
698 begin
702 -- Check for bad size clause given
707 Error_Msg_NE
712 -- Set size if not set already
719 ----------------
720 -- Size_Known --
721 ----------------
730 begin
734 -- Always True for scalar types. This is true even for generic formal
735 -- scalar types. We used to return False in the latter case, but the
736 -- size is known at compile time, even in the template, we just do
737 -- not know the exact size but that's not the point of this routine.
741 then
744 -- Array types
748 -- String literals always have known size, and we can set it
755 -- Unconstrained types never have known at compile time size
760 -- Don't do any recursion on type with error posted, since we may
761 -- have a malformed type that leads us into a loop.
766 -- Otherwise if component size unknown, then array size unknown
772 -- Check for all indexes static, and also compute possible size
773 -- (in case it is less than 32 and may be packable).
775 declare
779 begin
788 else
796 then
799 else
804 else
816 -- Access types always have known at compile time sizes
821 -- For non-generic private types, go to underlying type if present
826 then
827 -- Don't do any recursion on type with error posted, since we may
828 -- have a malformed type that leads us into a loop.
832 else
836 -- Record types
840 -- A class-wide type is never considered to have a known size
845 -- A subtype of a variant record must not have non-static
846 -- discriminated components.
850 then
853 -- Don't do any recursion on type with error posted, since we may
854 -- have a malformed type that leads us into a loop.
860 -- Now look at the components of the record
862 declare
863 -- The following two variables are used to keep track of the
864 -- size of packed records if we can tell the size of the packed
865 -- record in the front end. Packed_Size_Known is True if so far
866 -- we can figure out the size. It is initialized to True for a
867 -- packed record, unless the record has discriminants or atomic
868 -- components or independent components.
870 -- The reason we eliminate the discriminated case is that
871 -- we don't know the way the back end lays out discriminated
872 -- packed records. If Packed_Size_Known is True, then
873 -- Packed_Size is the size in bits so far.
882 -- Size in bits so far
884 begin
885 -- Test for variant part present
891 N_Record_Definition
893 and then
894 Present (Variant_Part
896 then
897 -- If variant part is present, and type is unconstrained,
898 -- then we must have defaulted discriminants, or a size
899 -- clause must be present for the type, or else the size
900 -- is definitely not known at compile time.
903 and then
906 then
911 -- Loop through components
917 -- We do not know the packed size if there is a component
918 -- clause present (we possibly could, but this would only
919 -- help in the case of a record with partial rep clauses.
920 -- That's because in the case of full rep clauses, the
921 -- size gets figured out anyway by a different circuit).
927 -- We do not know the packed size if we have a by reference
928 -- type, or an atomic type or an atomic component, or an
929 -- aliased component (because packing does not touch these).
935 then
939 -- We need to identify a component that is an array where
940 -- the index type is an enumeration type with non-standard
941 -- representation, and some bound of the type depends on a
942 -- discriminant.
944 -- This is because gigi computes the size by doing a
945 -- substitution of the appropriate discriminant value in
946 -- the size expression for the base type, and gigi is not
947 -- clever enough to evaluate the resulting expression (which
948 -- involves a call to rep_to_pos) at compile time.
950 -- It would be nice if gigi would either recognize that
951 -- this expression can be computed at compile time, or
952 -- alternatively figured out the size from the subtype
953 -- directly, where all the information is at hand ???
957 then
958 declare
966 begin
973 then
979 then
984 then
994 -- Clearly size of record is not known if the size of one of
995 -- the components is not known.
1001 -- Accumulate packed size if possible
1005 -- We can only deal with elementary types, since for
1006 -- non-elementary components, alignment enters into the
1007 -- picture, and we don't know enough to handle proper
1008 -- alignment in this context. Packed arrays count as
1009 -- elementary if the representation is a modular type.
1013 and then Present
1015 and then Is_Modular_Integer_Type
1017 then
1018 -- Packed size unknown if we have an atomic type
1019 -- or a by reference type, since the back end
1020 -- knows how these are layed out.
1024 then
1027 -- If RM_Size is known and static, then we can keep
1028 -- accumulating the packed size
1032 -- A little glitch, to be removed sometime ???
1033 -- gigi does not understand zero sizes yet.
1038 -- Normal case where we can keep accumulating the
1039 -- packed array size.
1041 else
1045 -- If we have a field whose RM_Size is not known then
1046 -- we can't figure out the packed size here.
1048 else
1052 -- If we have a non-elementary type we can't figure out
1053 -- the packed array size (alignment issues).
1055 else
1070 -- All other cases, size not known at compile time
1072 else
1077 -------------------------------------
1078 -- Static_Discriminated_Components --
1079 -------------------------------------
1081 function Static_Discriminated_Components
1083 is
1086 begin
1090 then
1104 -- Start of processing for Check_Compile_Time_Size
1106 begin
1110 -----------------------------------
1111 -- Check_Component_Storage_Order --
1112 -----------------------------------
1114 procedure Check_Component_Storage_Order
1119 is
1125 -- Set for the record case, True if Comp starts on a byte boundary
1126 -- (in which case it is allowed to have different storage order).
1129 -- Set True when the component is a nested composite, and it does not
1130 -- have the same scalar storage order as Encl_Type.
1134 begin
1135 -- Record case
1145 else
1146 -- If a component clause is present, check if the component starts
1147 -- on a storage element boundary. Otherwise conservatively assume
1148 -- it does so only in the case where the record is not packed.
1151 Comp_Byte_Aligned :=
1153 else
1160 -- Array case
1162 else
1169 -- Note: the Reverse_Storage_Order flag is set on the base type, but
1170 -- the attribute definition clause is attached to the first subtype.
1173 Comp_ADC := Get_Attribute_Definition_Clause
1175 Attribute_Scalar_Storage_Order);
1178 -- Case of record or array component: check storage order compatibility
1181 Comp_SSO_Differs :=
1183 /=
1186 -- Parent and extension must have same storage order
1190 Error_Msg_N
1195 -- If enclosing composite has explicit SSO then nested composite must
1196 -- have explicit SSO as well.
1202 -- If component and composite SSO differs, check that component
1203 -- falls on byte boundaries and isn't packed.
1207 -- Component SSO differs from enclosing composite:
1209 -- Reject if component is a packed array, as it may be represented
1210 -- as a scalar internally.
1213 Error_Msg_N
1217 -- Reject if composite is a packed array, as it may be rewritten
1218 -- into an array of scalars.
1224 -- Reject if not byte aligned
1227 and then not Comp_Byte_Aligned
1228 then
1229 Error_Msg_N
1235 -- Enclosing type has explicit SSO: non-composite component must not
1236 -- be aliased.
1239 Error_Msg_N
1245 -----------------------------
1246 -- Check_Debug_Info_Needed --
1247 -----------------------------
1250 begin
1255 or else Debug_Generated_Code
1256 or else Debug_Flag_VV
1258 then
1263 -------------------------------
1264 -- Check_Expression_Function --
1265 -------------------------------
1271 -- Function to search for deferred constant
1273 -------------------
1274 -- Find_Constant --
1275 -------------------
1278 begin
1279 -- When a constant is initialized with the result of a dispatching
1280 -- call, the constant declaration is rewritten as a renaming of the
1281 -- displaced function result. This scenario is not a premature use of
1282 -- a constant even though the Has_Completion flag is not set.
1289 N_Object_Declaration
1292 then
1293 Error_Msg_NE
1300 then
1310 -- Start of processing for Check_Expression_Function
1312 begin
1317 then
1322 ----------------------------
1323 -- Check_Strict_Alignment --
1324 ----------------------------
1329 begin
1347 then
1357 -------------------------
1358 -- Check_Unsigned_Type --
1359 -------------------------
1366 begin
1371 -- Do not attempt to analyze case where range was in error
1377 -- The situation that is non trivial is something like
1379 -- subtype x1 is integer range -10 .. +10;
1380 -- subtype x2 is x1 range 0 .. V1;
1381 -- subtype x3 is x2 range V2 .. V3;
1382 -- subtype x4 is x3 range V4 .. V5;
1384 -- where Vn are variables. Here the base type is signed, but we still
1385 -- know that x4 is unsigned because of the lower bound of x2.
1387 -- The only way to deal with this is to look up the ancestor chain
1390 loop
1404 else
1407 -- If no ancestor had a static lower bound, go to base type
1411 -- Note: the reason we still check for a compile time known
1412 -- value for the base type is that at least in the case of
1413 -- generic formals, we can have bounds that fail this test,
1414 -- and there may be other cases in error situations.
1426 then
1436 -------------------------
1437 -- Is_Atomic_Aggregate --
1438 -------------------------
1440 function Is_Atomic_Aggregate
1443 is
1449 begin
1452 -- Array may be qualified, so find outer context
1460 then
1462 New_N :=
1473 else
1478 -----------------------------------------------
1479 -- Explode_Initialization_Compound_Statement --
1480 -----------------------------------------------
1485 begin
1488 then
1491 -- Note that we rewrite Init_Stmts into a NULL statement, rather than
1492 -- just removing it, because Freeze_All may rely on this particular
1493 -- Node_Id still being present in the enclosing list to know where to
1494 -- stop freezing.
1502 ----------------
1503 -- Freeze_All --
1504 ----------------
1506 -- Note: the easy coding for this procedure would be to just build a
1507 -- single list of freeze nodes and then insert them and analyze them
1508 -- all at once. This won't work, because the analysis of earlier freeze
1509 -- nodes may recursively freeze types which would otherwise appear later
1510 -- on in the freeze list. So we must analyze and expand the freeze nodes
1511 -- as they are generated.
1518 -- This is the internal recursive routine that does freezing of entities
1519 -- (but NOT the analysis of default expressions, which should not be
1520 -- recursive, we don't want to analyze those till we are sure that ALL
1521 -- the types are frozen).
1523 --------------------
1524 -- Freeze_All_Ent --
1525 --------------------
1533 -- If freeze nodes are present, insert and analyze, and reset cursor
1534 -- for next insertion.
1536 -------------------
1537 -- Process_Flist --
1538 -------------------
1541 begin
1548 else
1554 -- Start or processing for Freeze_All_Ent
1556 begin
1560 -- If the entity is an inner package which is not a package
1561 -- renaming, then its entities must be frozen at this point. Note
1562 -- that such entities do NOT get frozen at the end of the nested
1563 -- package itself (only library packages freeze).
1565 -- Same is true for task declarations, where anonymous records
1566 -- created for entry parameters must be frozen.
1572 then
1583 then
1590 N_Single_Task_Declaration)
1591 then
1594 End_Scope;
1596 -- For a derived tagged type, we must ensure that all the
1597 -- primitive operations of the parent have been frozen, so that
1598 -- their addresses will be in the parent's dispatch table at the
1599 -- point it is inherited.
1605 then
1606 declare
1613 begin
1620 then
1622 Process_Flist;
1632 Process_Flist;
1634 -- If already frozen, and there are delayed aspects, this is where
1635 -- we do the visibility check for these aspects (see Sem_Ch13 spec
1636 -- for a description of how we handle aspect visibility).
1640 -- Retrieve the visibility to the discriminants in order to
1641 -- analyze properly the aspects.
1645 declare
1648 begin
1654 then
1665 -- If an incomplete type is still not frozen, this may be a
1666 -- premature freezing because of a body declaration that follows.
1667 -- Indicate where the freezing took place. Freezing will happen
1668 -- if the body comes from source, but not if it is internally
1669 -- generated, for example as the body of a type invariant.
1671 -- If the freezing is caused by the end of the current declarative
1672 -- part, it is a Taft Amendment type, and there is no error.
1676 then
1677 declare
1680 begin
1681 -- The presence of a body freezes all entities previously
1682 -- declared in the current list of declarations, but this
1683 -- does not apply if the body does not come from source.
1684 -- A type invariant is transformed into a subprogram body
1685 -- which is placed at the end of the private part of the
1686 -- current package, but this body does not freeze incomplete
1687 -- types that may be declared in this private part.
1690 N_Entry_Body,
1691 N_Package_Body,
1692 N_Protected_Body,
1693 N_Task_Body)
1695 and then
1698 then
1700 Error_Msg_NE
1711 -- Start of processing for Freeze_All
1713 begin
1716 -- Now that all types are frozen, we can deal with default expressions
1717 -- that require us to build a default expression functions. This is the
1718 -- point at which such functions are constructed (after all types that
1719 -- might be used in such expressions have been frozen).
1721 -- For subprograms that are renaming_as_body, we create the wrapper
1722 -- bodies as needed.
1724 -- We also add finalization chains to access types whose designated
1725 -- types are controlled. This is normally done when freezing the type,
1726 -- but this misses recursive type definitions where the later members
1727 -- of the recursion introduce controlled components.
1729 -- Loop through entities
1744 else
1750 and then
1752 = N_Subprogram_Renaming_Declaration
1753 then
1754 Build_And_Analyze_Renamed_Body
1761 N_Single_Task_Declaration)
1762 then
1763 declare
1766 begin
1771 then
1779 -- We add finalization masters to access types whose designated types
1780 -- require finalization. This is normally done when freezing the
1781 -- type, but this misses recursive type definitions where the later
1782 -- members of the recursion introduce controlled components (such as
1783 -- can happen when incomplete types are involved), as well cases
1784 -- where a component type is private and the controlled full type
1785 -- occurs after the access type is frozen. Cases that don't need a
1786 -- finalization master are generic formal types (the actual type will
1787 -- have it) and types derived from them, and types with Java and CIL
1788 -- conventions, since those are used for API bindings.
1789 -- (Are there any other cases that should be excluded here???)
1795 then
1803 -----------------------
1804 -- Freeze_And_Append --
1805 -----------------------
1807 procedure Freeze_And_Append
1811 is
1813 begin
1817 else
1823 -------------------
1824 -- Freeze_Before --
1825 -------------------
1830 begin
1840 -------------------
1841 -- Freeze_Entity --
1842 -------------------
1853 -- This could use a comment ???
1856 -- Used to detect attempt to freeze function declared in another unit
1859 -- List of freezing actions, left at No_List if none
1862 -- This flag gets set to true for a variable with default initialization
1865 -- N is a freezing action to be appended to the Result
1868 -- If Loc is a freeze_entity that appears after the last declaration
1869 -- in the scope, inhibit error messages on late completion.
1872 -- Check that an Access or Unchecked_Access attribute with a prefix
1873 -- which is the current instance type can only be applied when the type
1874 -- is limited.
1877 -- Give warning for modulus of 8, 16, 32, or 64 given as an explicit
1878 -- integer literal without an explicit corresponding size clause. The
1879 -- caller has checked that Utype is a modular integer type.
1882 -- Freeze array type, including freezing index and component types
1885 -- Create Freeze_Generic_Entity nodes for types declared in a generic
1886 -- package. Recurse on inner generic packages.
1889 -- Freeze formals and return type of subprogram. If some type in the
1890 -- profile is a limited view, freezing of the entity will take place
1891 -- elsewhere, and the function returns False. This routine will be
1892 -- modified if and when we can implement AI05-019 efficiently ???
1895 -- Freeze record type, including freezing component types, and freezing
1896 -- primitive operations if this is a tagged type.
1899 -- Determine whether an arbitrary entity is subject to Boolean aspect
1900 -- Import and its value is specified as True.
1903 -- Following AI05-151, a function can return a limited view of a type
1904 -- declared elsewhere. In that case the function cannot be frozen at
1905 -- the end of its enclosing package. If its first use is in a different
1906 -- unit, it cannot be frozen there, but if the call is legal the full
1907 -- view of the return type is available and the subprogram can now be
1908 -- frozen. However the freeze node cannot be inserted at the point of
1909 -- call, but rather must go in the package holding the function, so that
1910 -- the backend can process it in the proper context.
1913 -- If E is an entity for an imported subprogram with pre/post-conditions
1914 -- then this procedure will create a wrapper to ensure that proper run-
1915 -- time checking of the pre/postconditions. See body for details.
1917 -------------------
1918 -- Add_To_Result --
1919 -------------------
1922 begin
1925 else
1930 ----------------------------
1931 -- After_Last_Declaration --
1932 ----------------------------
1937 begin
1943 else
1947 else
1952 ----------------------------
1953 -- Check_Current_Instance --
1954 ----------------------------
1959 -- Determine whether Typ is compatible with the rules for aliased
1960 -- views of types as defined in RM 3.10 in the various dialects.
1963 -- Process routine to apply check to given node
1965 -----------------------------
1966 -- Is_Aliased_View_Of_Type --
1967 -----------------------------
1972 begin
1973 -- Common case
1977 then
1980 -- The following paragraphs describe what a legal aliased view of
1981 -- a type is in the various dialects of Ada.
1983 -- Ada 95
1985 -- The current instance of a limited type, and a formal parameter
1986 -- or generic formal object of a tagged type.
1988 -- Ada 95 limited type
1989 -- * Type with reserved word "limited"
1990 -- * A protected or task type
1991 -- * A composite type with limited component
1996 -- Ada 2005
1998 -- The current instance of a limited tagged type, a protected
1999 -- type, a task type, or a type that has the reserved word
2000 -- "limited" in its full definition ... a formal parameter or
2001 -- generic formal object of a tagged type.
2003 -- Ada 2005 limited type
2004 -- * Type with reserved word "limited", "synchronized", "task"
2005 -- or "protected"
2006 -- * A composite type with limited component
2007 -- * A derived type whose parent is a non-interface limited type
2010 return
2012 or else
2017 -- Ada 2012 and beyond
2019 -- The current instance of an immutably limited type ... a formal
2020 -- parameter or generic formal object of a tagged type.
2022 -- Ada 2012 limited type
2023 -- * Type with reserved word "limited", "synchronized", "task"
2024 -- or "protected"
2025 -- * A composite type with limited component
2026 -- * A derived type whose parent is a non-interface limited type
2027 -- * An incomplete view
2029 -- Ada 2012 immutably limited type
2030 -- * Explicitly limited record type
2031 -- * Record extension with "limited" present
2032 -- * Non-formal limited private type that is either tagged
2033 -- or has at least one access discriminant with a default
2034 -- expression
2035 -- * Task type, protected type or synchronized interface
2036 -- * Type derived from immutably limited type
2038 else
2039 return
2045 -------------
2046 -- Process --
2047 -------------
2050 begin
2054 Name_Unchecked_Access)
2058 then
2060 Error_Msg_N
2063 else
2064 Error_Msg_N
2071 else
2081 -- Local variables
2086 -- Start of processing for Check_Current_Instance
2088 begin
2094 ------------------------------
2095 -- Check_Suspicious_Modulus --
2096 ------------------------------
2101 begin
2107 declare
2110 begin
2112 declare
2116 begin
2118 declare
2122 begin
2123 -- First case, modulus and size are the same. This
2124 -- happens if you have something like mod 32, with
2125 -- an explicit size of 32, this is for sure a case
2126 -- where the warning is given, since it is seems
2127 -- very unlikely that someone would want e.g. a
2128 -- five bit type stored in 32 bits. It is much
2129 -- more likely they wanted a 32-bit type.
2134 -- Second case, the modulus is 32 or 64 and no
2135 -- size clause is present. This is a less clear
2136 -- case for giving the warning, but in the case
2137 -- of 32/64 (5-bit or 6-bit types) these seem rare
2138 -- enough that it is a likely error (and in any
2139 -- case using 2**5 or 2**6 in these cases seems
2140 -- clearer. We don't include 8 or 16 here, simply
2141 -- because in practice 3-bit and 4-bit types are
2142 -- more common and too many false positives if
2143 -- we warn in these cases.
2147 then
2150 -- No warning needed
2152 else
2156 -- If we fall through, give warning
2159 Error_Msg_N
2161 Modulus);
2170 -----------------------
2171 -- Freeze_Array_Type --
2172 -----------------------
2180 -- Set true if any of the index types is an enumeration type with a
2181 -- non-standard representation.
2183 begin
2192 then
2199 -- Processing that is done only for base types
2203 -- Deal with default setting of reverse storage order
2207 -- Propagate flags for component type
2211 then
2219 -- Warn for pragma Pack overriding foreign convention
2223 then
2224 declare
2229 begin
2233 Error_Msg_N
2236 Error_Msg_N
2243 -- If packing was requested or if the component size was
2244 -- set explicitly, then see if bit packing is required. This
2245 -- processing is only done for base types, since all of the
2246 -- representation aspects involved are type-related.
2248 -- This is not just an optimization, if we start processing the
2249 -- subtypes, they interfere with the settings on the base type
2250 -- (this is because Is_Packed has a slightly different meaning
2251 -- before and after freezing).
2253 declare
2257 begin
2261 then
2270 else
2273 -- We can set the component size if it is less than 16,
2274 -- rounding it up to the next storage unit size.
2280 else
2284 -- Set component size up to match alignment if it would
2285 -- otherwise be less than the alignment. This deals with
2286 -- cases of types whose alignment exceeds their size (the
2287 -- padded type cases).
2290 declare
2292 begin
2300 -- Case of component size that may result in packing
2303 declare
2309 Get_Attribute_Definition_Clause
2312 begin
2313 -- Warn if we have pack and component size so that the
2314 -- pack is ignored.
2316 -- Note: here we must check for the presence of a
2317 -- component size before checking for a Pack pragma to
2318 -- deal with the case where the array type is a derived
2319 -- type whose parent is currently private.
2323 and then Warn_On_Redundant_Constructs
2324 then
2326 Error_Msg_NE
2328 Error_Msg_N
2334 -- Set component size if not already set by a component
2335 -- size clause.
2341 -- Check for base type of 8, 16, 32 bits, where an
2342 -- unsigned subtype has a length one less than the
2343 -- base type (e.g. Natural subtype of Integer).
2345 -- In such cases, if a component size was not set
2346 -- explicitly, then generate a warning.
2352 then
2356 Error_Msg_N
2358 Pack_Pragma);
2359 Error_Msg_N
2361 Pack_Pragma);
2365 -- Actual packing is not needed for 8, 16, 32, 64. Also
2366 -- not needed for 24 if alignment is 1.
2373 then
2374 -- Here the array was requested to be packed, but
2375 -- the packing request had no effect, so Is_Packed
2376 -- is reset.
2378 -- Note: semantically this means that we lose track
2379 -- of the fact that a derived type inherited a pragma
2380 -- Pack that was non- effective, but that seems fine.
2382 -- We regard a Pack pragma as a request to set a
2383 -- representation characteristic, and this request
2384 -- may be ignored.
2391 then
2395 -- In all other cases, packing is indeed needed
2397 else
2402 -- Make sure that we have the necessary routines to
2403 -- implement the packing, and complain now if not.
2405 declare
2409 begin
2412 then
2413 Error_Msg_CRT
2424 -- Check for Atomic_Components or Aliased with unsuitable packing
2425 -- or explicit component size clause given.
2428 or else
2430 and then
2432 then
2436 -- Outputs error messages for incorrect CS clause or pragma
2437 -- Pack for aliased or atomic components (T is "aliased" or
2438 -- "atomic");
2440 -----------------
2441 -- Complain_CS --
2442 -----------------
2445 begin
2447 Clause :=
2448 Get_Attribute_Definition_Clause
2452 Error_Msg_N
2456 Error_Msg_N
2459 else
2460 Error_Msg_N
2465 else
2466 Error_Msg_N
2474 -- Start of processing for Alias_Atomic_Check
2476 begin
2477 -- If object size of component type isn't known, we cannot
2478 -- be sure so we defer to the back end.
2483 -- Case where component size has no effect. First check for
2484 -- object size of component type multiple of the storage
2485 -- unit size.
2489 -- OK in both packing case and component size case if RM
2490 -- size is known and static and same as the object size.
2492 and then
2496 -- Or if we have an explicit component size clause and
2497 -- the component size and object size are equal.
2499 or else
2502 then
2507 then
2512 then
2518 -- Warn for case of atomic type
2524 then
2525 Error_Msg_NE
2540 -- Check for scalar storage order
2542 declare
2544 begin
2545 Check_Component_Storage_Order
2548 ADC => Get_Attribute_Definition_Clause
2550 Attribute_Scalar_Storage_Order),
2554 -- Processing that is done only for subtypes
2556 else
2557 -- Acquire alignment from base type
2565 -- Specific checks for bit-packed arrays
2569 -- Check number of elements for bit packed arrays that come from
2570 -- source and have compile time known ranges. The bit-packed
2571 -- arrays circuitry does not support arrays with more than
2572 -- Integer'Last + 1 elements, and when this restriction is
2573 -- violated, causes incorrect data access.
2575 -- For the case where this is not compile time known, a run-time
2576 -- check should be generated???
2579 declare
2585 begin
2591 -- Never generate an error if any index is of a generic
2592 -- type. We will check this in instances.
2599 Ilen :=
2605 -- No attempt is made to check number of elements if not
2606 -- compile time known.
2619 then
2620 Error_Msg_N
2627 -- Check size
2630 declare
2634 begin
2635 -- It is not clear if it is possible to have no size clause
2636 -- at this stage, but it is not worth worrying about. Post
2637 -- error on the entity name in the size clause if present,
2638 -- else on the type entity itself.
2642 else
2649 -- If any of the index types was an enumeration type with a non-
2650 -- standard rep clause, then we indicate that the array type is
2651 -- always packed (even if it is not bit packed).
2660 -- If the array is packed, we must create the packed array type to be
2661 -- used to actually implement the type. This is only needed for real
2662 -- array types (not for string literal types, since they are present
2663 -- only for the front end).
2667 then
2671 -- Size information of packed array type is copied to the array
2672 -- type, since this is really the representation. But do not
2673 -- override explicit existing size values. If the ancestor subtype
2674 -- is constrained the Packed_Array_Impl_Type will be inherited
2675 -- from it, but the size may have been provided already, and
2676 -- must not be overridden either.
2679 and then
2682 then
2692 -- For non-packed arrays set the alignment of the array to the
2693 -- alignment of the component type if it is unknown. Skip this
2694 -- in atomic case (atomic arrays may need larger alignments).
2703 then
2708 -----------------------------
2709 -- Freeze_Generic_Entities --
2710 -----------------------------
2717 begin
2736 --------------------
2737 -- Freeze_Profile --
2738 --------------------
2745 begin
2746 -- Loop through formals
2752 -- AI05-0151: incomplete types can appear in a profile. By the
2753 -- time the entity is frozen, the full view must be available,
2754 -- unless it is a limited view.
2759 then
2771 then
2772 -- If the type of a formal is incomplete, subprogram is being
2773 -- frozen prematurely. Within an instance (but not within a
2774 -- wrapper package) this is an artifact of our need to regard
2775 -- the end of an instantiation as a freeze point. Otherwise it
2776 -- is a definite error.
2783 elsif not After_Last_Declaration
2784 and then not Freezing_Library_Level_Tagged_Type
2785 then
2787 Error_Msg
2792 -- Check suspicious parameter for C function. These tests apply
2793 -- only to exported/imported subprograms.
2795 if Warn_On_Export_Import
2798 or else
2805 then
2806 -- Qualify mention of formals with subprogram name
2810 -- Check suspicious use of fat C pointer
2814 then
2815 Error_Msg_N
2818 -- Check suspicious return of boolean
2825 then
2826 Error_Msg_N
2828 Error_Msg_N
2832 -- Check suspicious tagged type
2835 or else
2839 then
2840 Error_Msg_N
2844 -- Check wrong convention subprogram pointer
2848 then
2849 Error_Msg_N
2853 Error_Msg_NE
2858 -- Turn off name qualification after message output
2863 -- Check for unconstrained array in exported foreign convention
2864 -- case.
2870 and then Warn_On_Export_Import
2872 -- Exclude VM case, since both .NET and JVM can handle
2873 -- unconstrained arrays without a problem.
2876 then
2879 -- If this is an inherited operation, place the warning on
2880 -- the derived type declaration, rather than on the original
2881 -- subprogram.
2884 then
2890 else
2906 -- If the formal is an anonymous_access_to_subprogram
2907 -- freeze the subprogram type as well, to prevent
2908 -- scope anomalies in gigi, because there is no other
2909 -- clear point at which it could be frozen.
2913 then
2921 -- Case of function: similar checks on return type
2925 -- Check whether function is declared elsewhere.
2927 Late_Freezing :=
2932 -- Freeze return type
2936 -- AI05-0151: the return type may have been incomplete
2937 -- at the point of declaration. Replace it with the full
2938 -- view, unless the current type is a limited view. In
2939 -- that case the full view is in a different unit, and
2940 -- gigi finds the non-limited view after the other unit
2941 -- is elaborated.
2946 then
2950 -- If the return type is a limited view and the non-
2951 -- limited view is still incomplete, the function has
2952 -- to be frozen at a later time.
2956 and then
2958 then
2966 -- Check suspicious return type for C function
2968 if Warn_On_Export_Import
2970 or else
2973 then
2974 -- Check suspicious return of fat C pointer
2980 then
2984 -- Check suspicious return of boolean
2992 then
2993 declare
2996 begin
2997 Error_Msg_NE
2999 Error_Msg_NE
3004 -- Check suspicious return tagged type
3008 and then
3009 Is_Tagged_Type
3014 then
3018 -- Check return of wrong convention subprogram pointer
3024 then
3028 Error_Msg_NE
3034 -- Give warning for suspicious return of a result of an
3035 -- unconstrained array type in a foreign convention function.
3039 -- We are looking for a return of unconstrained array
3044 -- Exclude imported routines, the warning does not belong on
3045 -- the import, but rather on the routine definition.
3049 -- Exclude VM case, since both .NET and JVM can handle return
3050 -- of unconstrained arrays without a problem.
3054 -- Check that general warning is enabled, and that it is not
3055 -- suppressed for this particular case.
3057 and then Warn_On_Export_Import
3060 then
3069 ------------------------
3070 -- Freeze_Record_Type --
3071 ------------------------
3083 -- Set True if the record type scope Rec has been pushed on the scope
3084 -- stack. Needed for the analysis of delayed aspects specified to the
3085 -- components of Rec.
3088 -- Scalar_Storage_Order attribute definition clause for the record
3091 -- Set True if we find at least one component with no component
3092 -- clause (used to warn about useless Pack pragmas).
3095 -- Set True if we find at least one component with a component
3096 -- clause (used to warn about useless Bit_Order pragmas, and also
3097 -- to detect cases where Implicit_Packing may have an effect).
3100 -- Set True if we find at least one component which is aliased. This
3101 -- is used to prevent Implicit_Packing of the record, since packing
3102 -- cannot modify the size of alignment of an aliased component.
3105 -- Set True if we find at least one component whose type has a
3106 -- Scalar_Storage_Order attribute definition clause.
3109 -- Set False if we encounter a component of a non-scalar type
3113 -- Accumulates total RM_Size values and total Esize values of all
3114 -- scalar components. Used for processing of Implicit_Packing.
3117 -- If N is an allocator, possibly wrapped in one or more level of
3118 -- qualified expression(s), return the inner allocator node, else
3119 -- return Empty.
3122 -- If the component subtype is an access to a constrained subtype of
3123 -- an already frozen type, make the subtype frozen as well. It might
3124 -- otherwise be frozen in the wrong scope, and a freeze node on
3125 -- subtype has no effect. Similarly, if the component subtype is a
3126 -- regular (not protected) access to subprogram, set the anonymous
3127 -- subprogram type to frozen as well, to prevent an out-of-scope
3128 -- freeze node at some eventual point of call. Protected operations
3129 -- are handled elsewhere.
3132 -- Make sure that all types mentioned in Discrete_Choices of the
3133 -- variants referenceed by the Variant_Part VP are frozen. This is
3134 -- a recursive routine to deal with nested variants.
3136 ---------------------
3137 -- Check_Allocator --
3138 ---------------------
3142 begin
3144 loop
3149 else
3155 -----------------
3156 -- Check_Itype --
3157 -----------------
3162 begin
3165 then
3168 -- In addition, add an Itype_Reference to ensure that the
3169 -- access subtype is elaborated early enough. This cannot be
3170 -- done if the subtype may depend on discriminants.
3175 then
3183 then
3188 ------------------------------------
3189 -- Freeze_Choices_In_Variant_Part --
3190 ------------------------------------
3199 begin
3200 -- Loop through variants
3205 -- Loop through choices, checking that all types are frozen
3211 then
3218 -- Check for nested variant part to process
3232 -- Start of processing for Freeze_Record_Type
3234 begin
3235 -- Deal with delayed aspect specifications for components. The
3236 -- analysis of the aspect is required to be delayed to the freeze
3237 -- point, thus we analyze the pragma or attribute definition
3238 -- clause in the tree at this point. We also analyze the aspect
3239 -- specification node at the freeze point when the aspect doesn't
3240 -- correspond to pragma/attribute definition clause.
3246 then
3251 -- The visibility to the discriminants must be restored in
3252 -- order to properly analyze the aspects.
3265 -- Pop the scope if Rec scope has been pushed on the scope stack
3266 -- during the delayed aspect analysis process.
3273 Pop_Scope;
3276 -- Freeze components and embedded subtypes
3285 -- Handle the component and discriminant case
3288 declare
3291 begin
3292 -- Freezing a record type freezes the type of each of its
3293 -- components. However, if the type of the component is
3294 -- part of this record, we do not want or need a separate
3295 -- Freeze_Node. Note that Is_Itype is wrong because that's
3296 -- also set in private type cases. We also can't check for
3297 -- the Scope being exactly Rec because of private types and
3298 -- record extensions.
3303 then
3309 -- Warn for pragma Pack overriding foreign convention
3314 -- Don't warn for aliased components, since override
3315 -- cannot happen in that case.
3318 then
3319 declare
3324 begin
3328 Error_Msg_N
3330 PP);
3332 Error_Msg_NE
3339 -- Check for error of component clause given for variable
3340 -- sized type. We have to delay this test till this point,
3341 -- since the component type has to be frozen for us to know
3342 -- if it is variable length.
3347 -- We omit this test in a generic context, it will be
3348 -- applied at instantiation time.
3353 -- Also omit this test in CodePeer mode, since we do not
3354 -- have sufficient info on size and rep clauses.
3359 -- Omit check if component has a generic type. This can
3360 -- happen in an instantiation within a generic in ASIS
3361 -- mode, where we force freeze actions without full
3362 -- expansion.
3367 -- Do the check
3369 elsif not
3370 Size_Known_At_Compile_Time
3372 then
3373 Error_Msg_N
3378 else
3382 -- Case of component requires byte alignment
3386 -- Set the enclosing record to also require byte align
3390 -- Check for component clause that is inconsistent with
3391 -- the required byte boundary alignment.
3396 then
3397 Error_Msg_N
3405 -- Gather data for possible Implicit_Packing later. Note that at
3406 -- this stage we might be dealing with a real component, or with
3407 -- an implicit subtype declaration.
3411 else
3412 Scalar_Component_Total_RM_Size :=
3414 Scalar_Component_Total_Esize :=
3418 -- If the component is an Itype with Delayed_Freeze and is either
3419 -- a record or array subtype and its base type has not yet been
3420 -- frozen, we must remove this from the entity list of this record
3421 -- and put it on the entity list of the scope of its base type.
3422 -- Note that we know that this is not the type of a component
3423 -- since we cleared Has_Delayed_Freeze for it in the previous
3424 -- loop. Thus this must be the Designated_Type of an access type,
3425 -- which is the type of a component.
3433 then
3434 declare
3438 begin
3439 -- We have a difficult case to handle here. Suppose Rec is
3440 -- subtype being defined in a subprogram that's created as
3441 -- part of the freezing of Rec'Base. In that case, we know
3442 -- that Comp'Base must have already been frozen by the time
3443 -- we get to elaborate this because Gigi doesn't elaborate
3444 -- any bodies until it has elaborated all of the declarative
3445 -- part. But Is_Frozen will not be set at this point because
3446 -- we are processing code in lexical order.
3448 -- We detect this case by going up the Scope chain of Rec
3449 -- and seeing if we have a subprogram scope before reaching
3450 -- the top of the scope chain or that of Comp'Base. If we
3451 -- do, then mark that Comp'Base will actually be frozen. If
3452 -- so, we merely undelay it.
3469 else
3472 else
3476 -- Insert in entity list of scope of base type (which
3477 -- must be an enclosing scope, because still unfrozen).
3483 -- If the component is an access type with an allocator as default
3484 -- value, the designated type will be frozen by the corresponding
3485 -- expression in init_proc. In order to place the freeze node for
3486 -- the designated type before that for the current record type,
3487 -- freeze it now.
3489 -- Same process if the component is an array of access types,
3490 -- initialized with an aggregate. If the designated type is
3491 -- private, it cannot contain allocators, and it is premature
3492 -- to freeze the type, so we check for this as well.
3497 then
3498 declare
3502 begin
3505 -- If component is pointer to a class-wide type, freeze
3506 -- the specific type in the expression being allocated.
3507 -- The expression may be a subtype indication, in which
3508 -- case freeze the subtype mark.
3510 if Is_Class_Wide_Type
3512 then
3514 Freeze_And_Append
3518 then
3519 Freeze_And_Append
3527 else
3528 Freeze_And_Append
3536 then
3539 -- Freeze the designated type when initializing a component with
3540 -- an aggregate in case the aggregate contains allocators.
3542 -- type T is ...;
3543 -- type T_Ptr is access all T;
3544 -- type T_Array is array ... of T_Ptr;
3546 -- type Rec is record
3547 -- Comp : T_Array := (others => ...);
3548 -- end record;
3552 then
3553 declare
3556 Designated_Type
3559 begin
3560 -- The only case when this sort of freezing is not done is
3561 -- when the designated type is class-wide and the root type
3562 -- is the record owning the component. This scenario results
3563 -- in a circularity because the class-wide type requires
3564 -- primitives that have not been created yet as the root
3565 -- type is in the process of being frozen.
3567 -- type Rec is tagged;
3568 -- type Rec_Ptr is access all Rec'Class;
3569 -- type Rec_Array is array ... of Rec_Ptr;
3571 -- type Rec is record
3572 -- Comp : Rec_Array := (others => ...);
3573 -- end record;
3577 then
3585 then
3595 -- Deal with default setting of reverse storage order
3599 -- Check consistent attribute setting on component types
3601 SSO_ADC := Get_Attribute_Definition_Clause
3604 declare
3606 begin
3609 Check_Component_Storage_Order
3619 -- Now deal with reverse storage order/bit order issues
3623 -- Check compatibility of Scalar_Storage_Order with Bit_Order, if
3624 -- the former is specified.
3628 -- Note: report error on Rec, not on SSO_ADC, as ADC may apply
3629 -- to some ancestor type.
3632 Error_Msg_N
3637 -- Warn if there is an Scalar_Storage_Order attribute definition
3638 -- clause but no component clause, no component that itself has
3639 -- such an attribute definition, and no pragma Pack.
3642 or else
3643 SSO_ADC_Component
3644 or else
3646 then
3647 Error_Msg_N
3649 SSO_ADC);
3653 -- Deal with Bit_Order aspect
3661 then
3662 -- Warn if clause has no effect when no component clause is
3663 -- present, but suppress warning if the Bit_Order is required
3664 -- due to the presence of a Scalar_Storage_Order attribute.
3666 Error_Msg_N
3668 Error_Msg_N
3671 -- Here is where we do the processing to adjust component clauses
3672 -- for reversed bit order, when not using reverse SSO.
3676 then
3679 -- Case where we have both an explicit Bit_Order and the same
3680 -- Scalar_Storage_Order: leave record untouched, the back-end
3681 -- will take care of required layout conversions.
3683 else
3689 -- Complete error checking on record representation clause (e.g.
3690 -- overlap of components). This is called after adjusting the
3691 -- record for reverse bit order.
3693 declare
3695 begin
3701 -- Set OK_To_Reorder_Components depending on debug flags
3705 or else
3707 then
3712 -- Check for useless pragma Pack when all components placed. We only
3713 -- do this check for record types, not subtypes, since a subtype may
3714 -- have all its components placed, and it still makes perfectly good
3715 -- sense to pack other subtypes or the parent type. We do not give
3716 -- this warning if Optimize_Alignment is set to Space, since the
3717 -- pragma Pack does have an effect in this case (it always resets
3718 -- the alignment to one).
3722 and then not Unplaced_Component
3724 then
3725 -- Reset packed status. Probably not necessary, but we do it so
3726 -- that there is no chance of the back end doing something strange
3727 -- with this redundant indication of packing.
3731 -- Give warning if redundant constructs warnings on
3734 Error_Msg_N -- CODEFIX
3740 -- If this is the record corresponding to a remote type, freeze the
3741 -- remote type here since that is what we are semantically freezing.
3742 -- This prevents the freeze node for that type in an inner scope.
3749 -- Check for controlled components and unchecked unions.
3754 -- Do not set Has_Controlled_Component on a class-wide
3755 -- equivalent type. See Make_CW_Equivalent_Type.
3758 and then
3760 or else
3763 or else
3765 and then
3767 and then
3768 Has_Controlled_Component
3770 then
3778 -- Scan component declaration for likely misuses of current
3779 -- instance, either in a constraint or a default expression.
3789 -- Enforce the restriction that access attributes with a current
3790 -- instance prefix can only apply to limited types. This comment
3791 -- is floating here, but does not seem to belong here???
3793 -- Set component alignment if not otherwise already set
3797 -- For first subtypes, check if there are any fixed-point fields with
3798 -- component clauses, where we must check the size. This is not done
3799 -- till the freeze point since for fixed-point types, we do not know
3800 -- the size until the type is frozen. Similar processing applies to
3801 -- bit packed arrays.
3809 then
3810 Check_Size
3814 Junk);
3821 -- Generate warning for applying C or C++ convention to a record
3822 -- with discriminants. This is suppressed for the unchecked union
3823 -- case, since the whole point in this case is interface C. We also
3824 -- do not generate this within instantiations, since we will have
3825 -- generated a message on the template.
3830 or else
3833 and then not In_Instance
3836 then
3837 declare
3841 begin
3846 Error_Msg_N
3848 A2);
3849 else
3850 Error_Msg_N
3852 A2);
3855 Error_Msg_NE
3861 -- See if Size is too small as is (and implicit packing might help)
3865 -- No implicit packing if even one component is explicitly placed
3867 and then not Placed_Component
3869 -- Or even one component is aliased
3871 and then not Aliased_Component
3873 -- Must have size clause and all scalar components
3876 and then All_Scalar_Components
3878 -- Do not try implicit packing on records with discriminants, too
3879 -- complicated, especially in the variant record case.
3883 -- We can implicitly pack if the specified size of the record is
3884 -- less than the sum of the object sizes (no point in packing if
3885 -- this is not the case).
3889 -- And the total RM size cannot be greater than the specified size
3890 -- since otherwise packing will not get us where we have to be.
3894 -- Never do implicit packing in CodePeer or SPARK modes since
3895 -- we don't do any packing in these modes, since this generates
3896 -- over-complex code that confuses static analysis, and in
3897 -- general, neither CodePeer not GNATprove care about the
3898 -- internal representation of objects.
3901 then
3902 -- If implicit packing enabled, do it
3907 -- Otherwise flag the size clause
3909 else
3910 declare
3912 begin
3913 Error_Msg_NE -- CODEFIX
3915 Error_Msg_N -- CODEFIX
3922 -- The following checks are only relevant when SPARK_Mode is on as
3923 -- they are not standard Ada legality rules.
3928 -- A discriminated type cannot be effectively volatile
3929 -- (SPARK RM C.6(4)).
3934 -- A tagged type cannot be effectively volatile
3935 -- (SPARK RM C.6(5)).
3941 -- A non-effectively volatile record type cannot contain
3942 -- effectively volatile components (SPARK RM C.6(2)).
3944 else
3949 then
3951 Error_Msg_N
3961 -- All done if not a full record definition
3967 -- Finally we need to check the variant part to make sure that
3968 -- all types within choices are properly frozen as part of the
3969 -- freezing of the record type.
3976 begin
3977 -- Find component list
3989 then
3994 -- Case of variant part present
4000 -- Note: we used to call Check_Choices here, but it is too early,
4001 -- since predicated subtypes are frozen here, but their freezing
4002 -- actions are in Analyze_Freeze_Entity, which has not been called
4003 -- yet for entities frozen within this procedure, so we moved that
4004 -- call to the Analyze_Freeze_Entity for the record type.
4009 -------------------------------
4010 -- Has_Boolean_Aspect_Import --
4011 -------------------------------
4018 begin
4024 -- The value of aspect Import is True when the expression is
4025 -- either missing or it is explicitly set to True.
4031 then
4042 ----------------------------
4043 -- Late_Freeze_Subprogram --
4044 ----------------------------
4051 begin
4054 else
4061 ------------------------------
4062 -- Wrap_Imported_Subprogram --
4063 ------------------------------
4065 -- The issue here is that our normal approach of checking preconditions
4066 -- and postconditions does not work for imported procedures, since we
4067 -- are not generating code for the body. To get around this we create
4068 -- a wrapper, as shown by the following example:
4070 -- procedure K (A : Integer);
4071 -- pragma Import (C, K);
4073 -- The spec is rewritten by removing the effects of pragma Import, but
4074 -- leaving the convention unchanged, as though the source had said:
4076 -- procedure K (A : Integer);
4077 -- pragma Convention (C, K);
4079 -- and we create a body, added to the entity K freeze actions, which
4080 -- looks like:
4082 -- procedure K (A : Integer) is
4083 -- procedure K (A : Integer);
4084 -- pragma Import (C, K);
4085 -- begin
4086 -- K (A);
4087 -- end K;
4089 -- Now the contract applies in the normal way to the outer procedure,
4090 -- and the inner procedure has no contracts, so there is no problem
4091 -- in just calling it to get the original effect.
4093 -- In the case of a function, we create an appropriate return statement
4094 -- for the subprogram body that calls the inner procedure.
4106 begin
4107 -- Nothing to do if not imported
4112 -- Test enabling conditions for wrapping
4117 and then not GNATprove_Mode
4118 then
4119 -- Here we do the wrap
4121 -- Note on calls to Copy_Separate_Tree. The trees we are copying
4122 -- here are fully analyzed, but we definitely want fully syntactic
4123 -- unanalyzed trees in the body we construct, so that the analysis
4124 -- generates the right visibility, and that is exactly what the
4125 -- calls to Copy_Separate_Tree give us.
4127 -- Acquire copy of Inline pragma
4131 -- Fix up spec to be not imported any more
4138 -- Grab the subprogram declaration and specification
4142 -- Build parameter list that we need
4151 -- Build the call
4154 Stmt :=
4156 Expression =>
4161 else
4162 Stmt :=
4168 -- Now build the body
4170 Bod :=
4172 Specification =>
4176 Specification =>
4178 Iprag),
4179 Handled_Statement_Sequence =>
4184 -- Append the body to freeze result
4189 -- Case of imported subprogram that does not get wrapped
4191 else
4192 -- Set Is_Public. All imported entities need an external symbol
4193 -- created for them since they are always referenced from another
4194 -- object file. Note this used to be set when we set Is_Imported
4195 -- back in Sem_Prag, but now we delay it to this point, since we
4196 -- don't want to set this flag if we wrap an imported subprogram.
4202 -- Start of processing for Freeze_Entity
4204 begin
4205 -- We are going to test for various reasons why this entity need not be
4206 -- frozen here, but in the case of an Itype that's defined within a
4207 -- record, that test actually applies to the record.
4213 then
4217 -- Do not freeze if already frozen since we only need one freeze node
4222 -- It is improper to freeze an external entity within a generic because
4223 -- its freeze node will appear in a non-valid context. The entity will
4224 -- be frozen in the proper scope after the current generic is analyzed.
4225 -- However, aspects must be analyzed because they may be queried later
4226 -- within the generic itself, and the corresponding pragma or attribute
4227 -- definition has not been analyzed yet.
4236 -- AI05-0213: A formal incomplete type does not freeze the actual. In
4237 -- the instance, the same applies to the subtype renaming the actual.
4243 then
4246 -- Formal subprograms are never frozen
4251 -- Generic types are never frozen as they lack delayed semantic checks
4256 -- Do not freeze a global entity within an inner scope created during
4257 -- expansion. A call to subprogram E within some internal procedure
4258 -- (a stream attribute for example) might require freezing E, but the
4259 -- freeze node must appear in the same declarative part as E itself.
4260 -- The two-pass elaboration mechanism in gigi guarantees that E will
4261 -- be frozen before the inner call is elaborated. We exclude constants
4262 -- from this test, because deferred constants may be frozen early, and
4263 -- must be diagnosed (e.g. in the case of a deferred constant being used
4264 -- in a default expression). If the enclosing subprogram comes from
4265 -- source, or is a generic instance, then the freeze point is the one
4266 -- mandated by the language, and we freeze the entity. A subprogram that
4267 -- is a child unit body that acts as a spec does not have a spec that
4268 -- comes from source, but can only come from source.
4273 then
4274 declare
4277 begin
4284 then
4286 else
4295 -- Similarly, an inlined instance body may make reference to global
4296 -- entities, but these references cannot be the proper freezing point
4297 -- for them, and in the absence of inlining freezing will take place in
4298 -- their own scope. Normally instance bodies are analyzed after the
4299 -- enclosing compilation, and everything has been frozen at the proper
4300 -- place, but with front-end inlining an instance body is compiled
4301 -- before the end of the enclosing scope, and as a result out-of-order
4302 -- freezing must be prevented.
4304 elsif Front_End_Inlining
4305 and then In_Instance_Body
4307 then
4308 declare
4311 begin
4316 else
4330 -- Add checks to detect proper initialization of scalars that may appear
4331 -- as subprogram parameters.
4337 -- Deal with delayed aspect specifications. The analysis of the aspect
4338 -- is required to be delayed to the freeze point, thus we analyze the
4339 -- pragma or attribute definition clause in the tree at this point. We
4340 -- also analyze the aspect specification node at the freeze point when
4341 -- the aspect doesn't correspond to pragma/attribute definition clause.
4347 -- Here to freeze the entity
4351 -- Case of entity being frozen is other than a type
4355 -- If entity is exported or imported and does not have an external
4356 -- name, now is the time to provide the appropriate default name.
4357 -- Skip this if the entity is stubbed, since we don't need a name
4358 -- for any stubbed routine. For the case on intrinsics, if no
4359 -- external name is specified, then calls will be handled in
4360 -- Exp_Intr.Expand_Intrinsic_Call, and no name is needed. If an
4361 -- external name is provided, then Expand_Intrinsic_Call leaves
4362 -- calls in place for expansion by GIGI.
4368 then
4369 Set_Encoded_Interface_Name
4372 -- If entity is an atomic object appearing in a declaration and
4373 -- the expression is an aggregate, assign it to a temporary to
4374 -- ensure that the actual assignment is done atomically rather
4375 -- than component-wise (the assignment to the temp may be done
4376 -- component-wise, but that is harmless).
4383 then
4387 -- Subprogram case
4391 -- Check for needing to wrap imported subprogram
4395 -- Freeze all parameter types and the return type (RM 13.14(14)).
4396 -- However skip this for internal subprograms. This is also where
4397 -- any extra formal parameters are created since we now know
4398 -- whether the subprogram will use a foreign convention.
4400 -- In Ada 2012, freezing a subprogram does not always freeze
4401 -- the corresponding profile (see AI05-019). An attribute
4402 -- reference is not a freezing point of the profile.
4403 -- Other constructs that should not freeze ???
4405 -- This processing doesn't apply to internal entities (see below)
4413 -- Must freeze its parent first if it is a derived subprogram
4419 -- We don't freeze internal subprograms, because we don't normally
4420 -- want addition of extra formals or mechanism setting to happen
4421 -- for those. However we do pass through predefined dispatching
4422 -- cases, since extra formals may be needed in some cases, such as
4423 -- for the stream 'Input function (build-in-place formals).
4427 then
4436 -- If warning on suspicious contracts then check for the case of
4437 -- a postcondition other than False for a No_Return subprogram.
4440 and then Warn_On_Suspicious_Contract
4442 then
4443 declare
4447 begin
4450 Name_Postcondition,
4451 Name_Refined_Post)
4452 then
4453 Exp :=
4454 Expression
4459 then
4460 Error_Msg_NE
4471 -- Here for other than a subprogram or type
4473 else
4474 -- If entity has a type, and it is not a generic unit, then
4475 -- freeze it first (RM 13.14(10)).
4479 then
4482 -- For an object of an anonymous array type, aspects on the
4483 -- object declaration apply to the type itself. This is the
4484 -- case for Atomic_Components, Volatile_Components, and
4485 -- Independent_Components. In these cases analysis of the
4486 -- generated pragma will mark the anonymous types accordingly,
4487 -- and the object itself does not require a freeze node.
4493 then
4500 -- Special processing for objects created by object declaration
4504 -- Abstract type allowed only for C++ imported variables or
4505 -- constants.
4507 -- Note: we inhibit this check for objects that do not come
4508 -- from source because there is at least one case (the
4509 -- expansion of x'Class'Input where x is abstract) where we
4510 -- legitimately generate an abstract object.
4516 then
4521 Error_Msg_NE
4526 Error_Msg_N -- CODEFIX
4532 -- For object created by object declaration, perform required
4533 -- categorization (preelaborate and pure) checks. Defer these
4534 -- checks to freeze time since pragma Import inhibits default
4535 -- initialization and thus pragma Import affects these checks.
4539 -- If there is an address clause, check that it is valid
4543 -- Reset Is_True_Constant for aliased object. We consider that
4544 -- the fact that something is aliased may indicate that some
4545 -- funny business is going on, e.g. an aliased object is passed
4546 -- by reference to a procedure which captures the address of
4547 -- the object, which is later used to assign a new value. Such
4548 -- code is highly dubious, but we choose to make it "work" for
4549 -- aliased objects.
4551 -- However, we don't do that for internal entities. We figure
4552 -- that if we deliberately set Is_True_Constant for an internal
4553 -- entity, e.g. a dispatch table entry, then we mean it.
4557 then
4561 -- If the object needs any kind of default initialization, an
4562 -- error must be issued if No_Default_Initialization applies.
4563 -- The check doesn't apply to imported objects, which are not
4564 -- ever default initialized, and is why the check is deferred
4565 -- until freezing, at which point we know if Import applies.
4566 -- Deferred constants are also exempted from this test because
4567 -- their completion is explicit, or through an import pragma.
4571 then
4577 and then
4582 or else
4585 then
4587 Check_Restriction
4591 -- Check that a Thread_Local_Storage variable does not have
4592 -- default initialization, and any explicit initialization must
4593 -- either be the null constant or a static constant.
4596 declare
4598 begin
4599 if Has_Default_Initialization
4600 or else
4602 and then
4604 or else not
4606 or else
4608 then
4609 Error_Msg_NE
4612 Error_Msg_NE
4619 -- For imported objects, set Is_Public unless there is also an
4620 -- address clause, which means that there is no external symbol
4621 -- needed for the Import (Is_Public may still be set for other
4622 -- unrelated reasons). Note that we delayed this processing
4623 -- till freeze time so that we can be sure not to set the flag
4624 -- if there is an address clause. If there is such a clause,
4625 -- then the only purpose of the Import pragma is to suppress
4626 -- implicit initialization.
4632 -- For source objects that are not Imported and are library
4633 -- level, if no linker section pragma was given inherit the
4634 -- appropriate linker section from the corresponding type.
4640 then
4641 Set_Linker_Section_Pragma
4645 -- For convention C objects of an enumeration type, warn if
4646 -- the size is not integer size and no explicit size given.
4647 -- Skip warning for Boolean, and Character, assume programmer
4648 -- expects 8-bit sizes for these cases.
4651 or else
4658 then
4660 Error_Msg_N
4662 E);
4667 -- Check that a constant which has a pragma Volatile[_Components]
4668 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
4670 -- Note: Atomic[_Components] also sets Volatile[_Components]
4676 then
4677 -- Make sure we actually have a pragma, and have not merely
4678 -- inherited the indication from elsewhere (e.g. an address
4679 -- clause, which is not good enough in RM terms).
4682 or else
4684 then
4685 Error_Msg_N
4690 or else
4692 then
4693 Error_Msg_N
4699 -- Static objects require special handling
4703 then
4707 -- Remaining step is to layout objects
4711 then
4715 -- For an object that does not have delayed freezing, and whose
4716 -- initialization actions have been captured in a compound
4717 -- statement, move them back now directly within the enclosing
4718 -- statement sequence.
4722 then
4727 -- Case of a type or subtype being frozen
4729 else
4730 -- We used to check here that a full type must have preelaborable
4731 -- initialization if it completes a private type specified with
4732 -- pragma Preelaborable_Initialization, but that missed cases where
4733 -- the types occur within a generic package, since the freezing
4734 -- that occurs within a containing scope generally skips traversal
4735 -- of a generic unit's declarations (those will be frozen within
4736 -- instances). This check was moved to Analyze_Package_Specification.
4738 -- The type may be defined in a generic unit. This can occur when
4739 -- freezing a generic function that returns the type (which is
4740 -- defined in a parent unit). It is clearly meaningless to freeze
4741 -- this type. However, if it is a subtype, its size may be determi-
4742 -- nable and used in subsequent checks, so might as well try to
4743 -- compute it.
4745 -- In Ada 2012, Freeze_Entities is also used in the front end to
4746 -- trigger the analysis of aspect expressions, so in this case we
4747 -- want to continue the freezing process.
4751 and then
4754 then
4759 -- Check for error of Type_Invariant'Class applied to an untagged
4760 -- type (check delayed to freeze time when full type is available).
4762 declare
4764 begin
4768 then
4769 Error_Msg_NE
4772 Error_Msg_N
4777 -- Deal with special cases of freezing for subtype
4781 -- Before we do anything else, a specialized test for the case of
4782 -- a size given for an array where the array needs to be packed,
4783 -- but was not so the size cannot be honored. This is the case
4784 -- where implicit packing may apply. The reason we do this so
4785 -- early is that if we have implicit packing, the layout of the
4786 -- base type is affected, so we must do this before we freeze
4787 -- the base type.
4789 -- We could do this processing only if implicit packing is enabled
4790 -- since in all other cases, the error would be caught by the back
4791 -- end. However, we choose to do the check even if we do not have
4792 -- implicit packing enabled, since this allows us to give a more
4793 -- useful error message (advising use of pragmas Implicit_Packing
4794 -- or Pack).
4797 declare
4808 -- Number of elements in array
4810 begin
4811 -- Check enabling conditions. These are straightforward
4812 -- except for the test for a limited composite type. This
4813 -- eliminates the rare case of a array of limited components
4814 -- where there are issues of whether or not we can go ahead
4815 -- and pack the array (since we can't freely pack and unpack
4816 -- arrays if they are limited).
4818 -- Note that we check the root type explicitly because the
4819 -- whole point is we are doing this test before we have had
4820 -- a chance to freeze the base type (and it is that freeze
4821 -- action that causes stuff to be inherited).
4834 then
4835 -- Compute number of elements in array
4843 and then
4845 then
4849 Num_Elmts :=
4850 Num_Elmts *
4856 -- What we are looking for here is the situation where
4857 -- the RM_Size given would be exactly right if there was
4858 -- a pragma Pack (resulting in the component size being
4859 -- the same as the RM_Size). Furthermore, the component
4860 -- type size must be an odd size (not a multiple of
4861 -- storage unit). If the component RM size is an exact
4862 -- number of storage units that is a power of two, the
4863 -- array is not packed and has a standard representation.
4867 then
4868 -- For implicit packing mode, just set the component
4869 -- size silently.
4877 -- Otherwise give an error message
4879 else
4880 Error_Msg_NE
4882 Error_Msg_N -- CODEFIX
4888 and then Implicit_Packing
4889 and then
4891 or else
4893 or else
4895 then
4896 -- Not a packed array, but indicate the desired
4897 -- component size, for the back-end.
4907 -- If ancestor subtype present, freeze that first. Note that this
4908 -- will also get the base type frozen. Need RM reference ???
4915 -- No ancestor subtype present
4917 else
4918 -- See if we have a nearest ancestor that has a predicate.
4919 -- That catches the case of derived type with a predicate.
4920 -- Need RM reference here ???
4928 -- Freeze base type before freezing the entity (RM 13.14(15))
4935 -- A subtype inherits all the type-related representation aspects
4936 -- from its parents (RM 13.1(8)).
4940 -- For a derived type, freeze its parent type first (RM 13.14(15))
4946 -- A derived type inherits each type-related representation aspect
4947 -- of its parent type that was directly specified before the
4948 -- declaration of the derived type (RM 13.1(15)).
4953 -- Check for incompatible size and alignment for record type
4955 if Warn_On_Size_Alignment
4959 -- If explicit Object_Size clause given assume that the programmer
4960 -- knows what he is doing, and expects the compiler behavior.
4964 -- Check for size not a multiple of alignment
4967 then
4968 declare
4974 begin
4977 -- Give a warning
4981 Error_Msg_NE
4987 else
4989 Error_Msg_NE
5002 -- Array type
5007 -- For a class-wide type, the corresponding specific type is
5008 -- frozen as well (RM 13.14(15))
5013 -- If the base type of the class-wide type is still incomplete,
5014 -- the class-wide remains unfrozen as well. This is legal when
5015 -- E is the formal of a primitive operation of some other type
5016 -- which is being frozen.
5023 -- The equivalent type associated with a class-wide subtype needs
5024 -- to be frozen to ensure that its layout is done.
5028 then
5032 -- Generate an itype reference for a library-level class-wide type
5033 -- at the freeze point. Otherwise the first explicit reference to
5034 -- the type may appear in an inner scope which will be rejected by
5035 -- the back-end.
5039 then
5040 declare
5043 begin
5046 -- From a gigi point of view, a class-wide subtype derives
5047 -- from its record equivalent type. As a result, the itype
5048 -- reference must appear after the freeze node of the
5049 -- equivalent type or gigi will reject the reference.
5053 then
5055 else
5061 -- For a record type or record subtype, freeze all component types
5062 -- (RM 13.14(15)). We test for E_Record_(sub)Type here, rather than
5063 -- using Is_Record_Type, because we don't want to attempt the freeze
5064 -- for the case of a private type with record extension (we will do
5065 -- that later when the full type is frozen).
5070 then
5073 -- For a concurrent type, freeze corresponding record type. This does
5074 -- not correspond to any specific rule in the RM, but the record type
5075 -- is essentially part of the concurrent type. Also freeze all local
5076 -- entities. This includes record types created for entry parameter
5077 -- blocks and whatever local entities may appear in the private part.
5091 -- The guard on the presence of the Etype seems to be needed
5092 -- for some CodePeer (-gnatcC) cases, but not clear why???
5097 then
5108 -- Private types are required to point to the same freeze node as
5109 -- their corresponding full views. The freeze node itself has to
5110 -- point to the partial view of the entity (because from the partial
5111 -- view, we can retrieve the full view, but not the reverse).
5112 -- However, in order to freeze correctly, we need to freeze the full
5113 -- view. If we are freezing at the end of a scope (or within the
5114 -- scope) of the private type, the partial and full views will have
5115 -- been swapped, the full view appears first in the entity chain and
5116 -- the swapping mechanism ensures that the pointers are properly set
5117 -- (on scope exit).
5119 -- If we encounter the partial view before the full view (e.g. when
5120 -- freezing from another scope), we freeze the full view, and then
5121 -- set the pointers appropriately since we cannot rely on swapping to
5122 -- fix things up (subtypes in an outer scope might not get swapped).
5124 -- If the full view is itself private, the above requirements apply
5125 -- to the underlying full view instead of the full view. But there is
5126 -- no swapping mechanism for the underlying full view so we need to
5127 -- set the pointers appropriately in both cases.
5131 then
5132 -- The construction of the dispatch table associated with library
5133 -- level tagged types forces freezing of all the primitives of the
5134 -- type, which may cause premature freezing of the partial view.
5135 -- For example:
5137 -- package Pkg is
5138 -- type T is tagged private;
5139 -- type DT is new T with private;
5140 -- procedure Prim (X : in out T; Y : in out DT'Class);
5141 -- private
5142 -- type T is tagged null record;
5143 -- Obj : T;
5144 -- type DT is new T with null record;
5145 -- end;
5147 -- In this case the type will be frozen later by the usual
5148 -- mechanism: an object declaration, an instantiation, or the
5149 -- end of a declarative part.
5153 then
5157 -- Case of full view present
5161 -- If full view has already been frozen, then no further
5162 -- processing is required
5168 -- Otherwise freeze full view and patch the pointers so that
5169 -- the freeze node will elaborate both views in the back end.
5170 -- However, if full view is itself private, freeze underlying
5171 -- full view instead and patch the pointers so that the freeze
5172 -- node will elaborate the three views in the back end.
5174 else
5175 declare
5178 begin
5181 then
5189 then
5196 else
5209 else
5210 -- {Incomplete,Private}_Subtypes with Full_Views
5211 -- constrained by discriminants.
5222 -- AI-117 requires that the convention of a partial view be the
5223 -- same as the convention of the full view. Note that this is a
5224 -- recognized breach of privacy, but it's essential for logical
5225 -- consistency of representation, and the lack of a rule in
5226 -- RM95 was an oversight.
5233 -- Size information is copied from the full view to the
5234 -- incomplete or private view for consistency.
5236 -- We skip this is the full view is not a type. This is very
5237 -- strange of course, and can only happen as a result of
5238 -- certain illegalities, such as a premature attempt to derive
5239 -- from an incomplete type.
5248 -- Case of underlying full view present
5252 then
5257 -- Patch the pointers so that the freeze node will elaborate
5258 -- both views in the back end.
5267 else
5277 -- Case of no full view present. If entity is derived or subtype,
5278 -- it is safe to freeze, correctness depends on the frozen status
5279 -- of parent. Otherwise it is either premature usage, or a Taft
5280 -- amendment type, so diagnosis is at the point of use and the
5281 -- type might be frozen later.
5286 else
5291 -- For access subprogram, freeze types of all formals, the return
5292 -- type was already frozen, since it is the Etype of the function.
5293 -- Formal types can be tagged Taft amendment types, but otherwise
5294 -- they cannot be incomplete.
5302 then
5306 -- AI05-151: Incomplete types are allowed in access to
5307 -- subprogram specifications.
5310 Error_Msg_NE
5321 -- For access to a protected subprogram, freeze the equivalent type
5322 -- (however this is not set if we are not generating code or if this
5323 -- is an anonymous type used just for resolution).
5331 -- Generic types are never seen by the back-end, and are also not
5332 -- processed by the expander (since the expander is turned off for
5333 -- generic processing), so we never need freeze nodes for them.
5339 -- Some special processing for non-generic types to complete
5340 -- representation details not known till the freeze point.
5345 -- Some error checks required for ordinary fixed-point type. Defer
5346 -- these till the freeze-point since we need the small and range
5347 -- values. We only do these checks for base types
5352 Error_Msg_N
5357 Error_Msg_N
5363 Error_Msg_N
5369 Error_Msg_N
5381 and then Warn_On_Suspicious_Modulus_Value
5382 then
5388 then
5389 -- If a pragma Default_Storage_Pool applies, and this type has no
5390 -- Storage_Pool or Storage_Size clause (which must have occurred
5391 -- before the freezing point), then use the default. This applies
5392 -- only to base types.
5394 -- None of this applies to access to subprograms, for which there
5395 -- are clearly no pools.
5401 then
5402 -- Case of pragma Default_Storage_Pool (null)
5407 -- Case of pragma Default_Storage_Pool (storage_pool_NAME)
5409 else
5414 -- Check restriction for standard storage pool
5420 -- Deal with error message for pure access type. This is not an
5421 -- error in Ada 2005 if there is no pool (see AI-366).
5427 then
5431 Error_Msg_N
5435 Error_Msg_N
5438 else
5439 Error_Msg_N
5446 -- Case of composite types
5450 -- AI-117 requires that all new primitives of a tagged type must
5451 -- inherit the convention of the full view of the type. Inherited
5452 -- and overriding operations are defined to inherit the convention
5453 -- of their parent or overridden subprogram (also specified in
5454 -- AI-117), which will have occurred earlier (in Derive_Subprogram
5455 -- and New_Overloaded_Entity). Here we set the convention of
5456 -- primitives that are still convention Ada, which will ensure
5457 -- that any new primitives inherit the type's convention. Class-
5458 -- wide types can have a foreign convention inherited from their
5459 -- specific type, but are excluded from this since they don't have
5460 -- any associated primitives.
5465 then
5466 declare
5470 begin
5482 -- If the type is a simple storage pool type, then this is where
5483 -- we attempt to locate and validate its Allocate, Deallocate, and
5484 -- Storage_Size operations (the first is required, and the latter
5485 -- two are optional). We also verify that the full type for a
5486 -- private type is allowed to be a simple storage pool type.
5490 then
5491 -- If the type is marked Has_Private_Declaration, then this is
5492 -- a full type for a private type that was specified with the
5493 -- pragma Simple_Storage_Pool_Type, and here we ensure that the
5494 -- pragma is allowed for the full type (for example, it can't
5495 -- be an array type, or a nonlimited record type).
5500 then
5502 Error_Msg_N
5513 procedure Validate_Simple_Pool_Op_Formal
5520 -- Validate one formal Pool_Op_Formal of the candidate pool
5521 -- operation Pool_Op. The formal must be of Expected_Type
5522 -- and have mode Expected_Mode. OK_Formal will be set to
5523 -- False if the formal doesn't match. If OK_Formal is False
5524 -- on entry, then the formal will effectively be ignored
5525 -- (because validation of the pool op has already failed).
5526 -- Upon return, Pool_Op_Formal will be updated to the next
5527 -- formal, if any.
5529 procedure Validate_Simple_Pool_Operation
5531 -- Search for and validate a simple pool operation with the
5532 -- name Op_Name. If the name is Allocate, then there must be
5533 -- exactly one such primitive operation for the simple pool
5534 -- type. If the name is Deallocate or Storage_Size, then
5535 -- there can be at most one such primitive operation. The
5536 -- profile of the located primitive must conform to what
5537 -- is expected for each operation.
5539 ------------------------------------
5540 -- Validate_Simple_Pool_Op_Formal --
5541 ------------------------------------
5543 procedure Validate_Simple_Pool_Op_Formal
5550 is
5551 begin
5552 -- If OK_Formal is False on entry, then simply ignore
5553 -- the formal, because an earlier formal has already
5554 -- been flagged.
5559 -- If no formal is passed in, then issue an error for a
5560 -- missing formal.
5563 Error_Msg_NE
5573 -- If the pool type was expected for this formal, then
5574 -- this will not be considered a candidate operation
5575 -- for the simple pool, so we unset OK_Formal so that
5576 -- the op and any later formals will be ignored.
5583 else
5584 Error_Msg_NE
5591 -- Issue error if formal's mode is not the expected one
5594 Error_Msg_N
5596 Pool_Op_Formal);
5599 -- Advance to the next formal
5604 ------------------------------------
5605 -- Validate_Simple_Pool_Operation --
5606 ------------------------------------
5608 procedure Validate_Simple_Pool_Operation
5610 is
5616 begin
5617 pragma Assert
5619 Name_Deallocate,
5620 Name_Storage_Size));
5624 -- For each homonym declared immediately in the scope
5625 -- of the simple storage pool type, determine whether
5626 -- the homonym is an operation of the pool type, and,
5627 -- if so, check that its profile is as expected for
5628 -- a simple pool operation of that name.
5634 then
5639 -- The first parameter must be of the pool type
5640 -- in order for the operation to qualify.
5643 Validate_Simple_Pool_Op_Formal
5646 else
5647 Validate_Simple_Pool_Op_Formal
5652 -- If another operation with this name has already
5653 -- been located for the type, then flag an error,
5654 -- since we only allow the type to have a single
5655 -- such primitive.
5658 Error_Msg_NE
5663 -- In the case of Allocate and Deallocate, a formal
5664 -- of type System.Address is required.
5667 Validate_Simple_Pool_Op_Formal
5672 Validate_Simple_Pool_Op_Formal
5677 -- In the case of Allocate and Deallocate, formals
5678 -- of type Storage_Count are required as the third
5679 -- and fourth parameters.
5682 Validate_Simple_Pool_Op_Formal
5685 Validate_Simple_Pool_Op_Formal
5690 -- If no mismatched formals have been found (Is_OK)
5691 -- and no excess formals are present, then this
5692 -- operation has been validated, so record it.
5702 -- There must be a valid Allocate operation for the type,
5703 -- so issue an error if none was found.
5707 then
5713 -- Simple pool operations can't be abstract
5716 Error_Msg_N
5721 -- The Storage_Size operation must be a function with
5722 -- Storage_Count as its result type.
5726 Error_Msg_N
5730 Error_Msg_NE
5735 -- Allocate and Deallocate must be procedures
5738 Error_Msg_N
5744 -- Start of processing for Validate_Simple_Pool_Ops
5746 begin
5754 -- Now that all types from which E may depend are frozen, see if the
5755 -- size is known at compile time, if it must be unsigned, or if
5756 -- strict alignment is required
5765 -- Do not allow a size clause for a type which does not have a size
5766 -- that is known at compile time
5770 then
5771 -- Suppress this message if errors posted on E, even if we are
5772 -- in all errors mode, since this is often a junk message
5775 Error_Msg_N
5781 -- Now we set/verify the representation information, in particular
5782 -- the size and alignment values. This processing is not required for
5783 -- generic types, since generic types do not play any part in code
5784 -- generation, and so the size and alignment values for such types
5785 -- are irrelevant. Ditto for types declared within a generic unit,
5786 -- which may have components that depend on generic parameters, and
5787 -- that will be recreated in an instance.
5792 -- Otherwise we call the layout procedure
5794 else
5798 -- If this is an access to subprogram whose designated type is itself
5799 -- a subprogram type, the return type of this anonymous subprogram
5800 -- type must be decorated as well.
5804 then
5808 -- If the type has a Defaut_Value/Default_Component_Value aspect,
5809 -- this is where we analye the expression (after the type is frozen,
5810 -- since in the case of Default_Value, we are analyzing with the
5811 -- type itself, and we treat Default_Component_Value similarly for
5812 -- the sake of uniformity).
5815 declare
5820 begin
5825 else
5836 Flag_Non_Static_Expr
5843 -- End of freeze processing for type entities
5846 -- Here is where we logically freeze the current entity. If it has a
5847 -- freeze node, then this is the point at which the freeze node is
5848 -- linked into the result list.
5852 -- If a freeze node is already allocated, use it, otherwise allocate
5853 -- a new one. The preallocation happens in the case of anonymous base
5854 -- types, where we preallocate so that we can set First_Subtype_Link.
5855 -- Note that we reset the Sloc to the current freeze location.
5861 else
5872 -- A final pass over record types with discriminants. If the type
5873 -- has an incomplete declaration, there may be constrained access
5874 -- subtypes declared elsewhere, which do not depend on the discrimi-
5875 -- nants of the type, and which are used as component types (i.e.
5876 -- the full view is a recursive type). The designated types of these
5877 -- subtypes can only be elaborated after the type itself, and they
5878 -- need an itype reference.
5882 then
5883 declare
5888 begin
5898 then
5910 -- When a type is frozen, the first subtype of the type is frozen as
5911 -- well (RM 13.14(15)). This has to be done after freezing the type,
5912 -- since obviously the first subtype depends on its own base type.
5917 -- If we just froze a tagged non-class wide record, then freeze the
5918 -- corresponding class-wide type. This must be done after the tagged
5919 -- type itself is frozen, because the class-wide type refers to the
5920 -- tagged type which generates the class.
5925 then
5932 -- Special handling for subprograms
5936 -- If subprogram has address clause then reset Is_Public flag, since
5937 -- we do not want the backend to generate external references.
5941 then
5949 -----------------------------
5950 -- Freeze_Enumeration_Type --
5951 -----------------------------
5954 begin
5955 -- By default, if no size clause is present, an enumeration type with
5956 -- Convention C is assumed to interface to a C enum, and has integer
5957 -- size. This applies to types. For subtypes, verify that its base
5958 -- type has no size clause either. Treat other foreign conventions
5959 -- in the same way, and also make sure alignment is set right.
5966 -- Don't do this if Short_Enums on target
5968 and then not Target_Short_Enums
5969 then
5973 -- Normal Ada case or size clause present or not Long_C_Enums on target
5975 else
5976 -- If the enumeration type interfaces to C, and it has a size clause
5977 -- that specifies less than int size, it warrants a warning. The
5978 -- user may intend the C type to be an enum or a char, so this is
5979 -- not by itself an error that the Ada compiler can detect, but it
5980 -- it is a worth a heads-up. For Boolean and Character types we
5981 -- assume that the programmer has the proper C type in mind.
5989 -- Don't do this if Short_Enums on target
5991 and then not Target_Short_Enums
5992 then
5993 Error_Msg_N
6001 -----------------------
6002 -- Freeze_Expression --
6003 -----------------------
6014 -- This flag is set true if the entity must be frozen outside the
6015 -- current subprogram. This happens in the case of expander generated
6016 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
6017 -- not freeze all entities like other bodies, but which nevertheless
6018 -- may reference entities that have to be frozen before the body and
6019 -- obviously cannot be frozen inside the body.
6022 -- If the expression is an array aggregate, the type of the component
6023 -- expressions is also frozen. If the component type is an access type
6024 -- and the expressions include allocators, the designed type is frozen
6025 -- as well.
6028 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
6029 -- it is the handled statement sequence of an expander-generated
6030 -- subprogram (init proc, stream subprogram, or renaming as body).
6031 -- If so, this is not a freezing context.
6033 -----------------------------------------
6034 -- Find_Aggregate_Component_Desig_Type --
6035 -----------------------------------------
6041 begin
6067 ----------------------
6068 -- In_Expanded_Body --
6069 ----------------------
6075 begin
6078 else
6085 else
6088 -- The following are expander-created bodies, or bodies that
6089 -- are not freeze points.
6098 N_Subprogram_Renaming_Declaration,
6099 N_Expression_Function))
6100 then
6102 else
6108 -- Start of processing for Freeze_Expression
6110 begin
6111 -- Immediate return if freezing is inhibited. This flag is set by the
6112 -- analyzer to stop freezing on generated expressions that would cause
6113 -- freezing if they were in the source program, but which are not
6114 -- supposed to freeze, since they are created.
6120 -- If expression is non-static, then it does not freeze in a default
6121 -- expression, see section "Handling of Default Expressions" in the
6122 -- spec of package Sem for further details. Note that we have to make
6123 -- sure that we actually have a real expression (if we have a subtype
6124 -- indication, we can't test Is_OK_Static_Expression). However, we
6125 -- exclude the case of the prefix of an attribute of a static scalar
6126 -- subtype from this early return, because static subtype attributes
6127 -- should always cause freezing, even in default expressions, but
6128 -- the attribute may not have been marked as static yet (because in
6129 -- Resolve_Attribute, the call to Eval_Attribute follows the call of
6130 -- Freeze_Expression on the prefix).
6132 if In_Spec_Exp
6139 then
6143 -- Freeze type of expression if not frozen already
6151 -- Base type may be an derived numeric type that is frozen at
6152 -- the point of declaration, but first_subtype is still unfrozen.
6159 -- For entity name, freeze entity if not frozen already. A special
6160 -- exception occurs for an identifier that did not come from source.
6161 -- We don't let such identifiers freeze a non-internal entity, i.e.
6162 -- an entity that did come from source, since such an identifier was
6163 -- generated by the expander, and cannot have any semantic effect on
6164 -- the freezing semantics. For example, this stops the parameter of
6165 -- an initialization procedure from freezing the variable.
6172 then
6179 else
6183 -- For an allocator freeze designated type if not frozen already
6185 -- For an aggregate whose component type is an access type, freeze the
6186 -- designated type now, so that its freeze does not appear within the
6187 -- loop that might be created in the expansion of the aggregate. If the
6188 -- designated type is a private type without full view, the expression
6189 -- cannot contain an allocator, so the type is not frozen.
6191 -- For a function, we freeze the entity when the subprogram declaration
6192 -- is frozen, but a function call may appear in an initialization proc.
6193 -- before the declaration is frozen. We need to generate the extra
6194 -- formals, if any, to ensure that the expansion of the call includes
6195 -- the proper actuals. This only applies to Ada subprograms, not to
6196 -- imported ones.
6207 then
6209 -- Check whether aggregate includes allocators.
6214 when N_Selected_Component |
6215 N_Indexed_Component |
6216 N_Slice =>
6227 then
6238 then
6242 -- All done if nothing needs freezing
6247 then
6251 -- Examine the enclosing context by climbing the parent chain. The
6252 -- traversal serves two purposes - to detect scenarios where freezeing
6253 -- is not needed and to find the proper insertion point for the freeze
6254 -- nodes. Although somewhat similar to Insert_Actions, this traversal
6255 -- is freezing semantics-sensitive. Inserting freeze nodes blindly in
6256 -- the tree may result in types being frozen too early.
6259 loop
6262 -- If we don't have a parent, then we are not in a well-formed tree.
6263 -- This is an unusual case, but there are some legitimate situations
6264 -- in which this occurs, notably when the expressions in the range of
6265 -- a type declaration are resolved. We simply ignore the freeze
6266 -- request in this case. Is this right ???
6272 -- See if we have got to an appropriate point in the tree
6276 -- A special test for the exception of (RM 13.14(8)) for the case
6277 -- of per-object expressions (RM 3.8(18)) occurring in component
6278 -- definition or a discrete subtype definition. Note that we test
6279 -- for a component declaration which includes both cases we are
6280 -- interested in, and furthermore the tree does not have explicit
6281 -- nodes for either of these two constructs.
6285 -- The case we want to test for here is an identifier that is
6286 -- a per-object expression, this is either a discriminant that
6287 -- appears in a context other than the component declaration
6288 -- or it is a reference to the type of the enclosing construct.
6290 -- For either of these cases, we skip the freezing
6292 if not In_Spec_Expression
6295 then
6296 -- We recognize the discriminant case by just looking for
6297 -- a reference to a discriminant. It can only be one for
6298 -- the enclosing construct. Skip freezing in this case.
6303 -- For the case of a reference to the enclosing record,
6304 -- (or task or protected type), we look for a type that
6305 -- matches the current scope.
6312 -- If we have an enumeration literal that appears as the choice in
6313 -- the aggregate of an enumeration representation clause, then
6314 -- freezing does not occur (RM 13.14(10)).
6318 -- The case we are looking for is an enumeration literal
6322 then
6323 -- If enumeration literal appears directly as the choice,
6324 -- do not freeze (this is the normal non-overloaded case)
6328 then
6331 -- If enumeration literal appears as the name of function
6332 -- which is the choice, then also do not freeze. This
6333 -- happens in the overloaded literal case, where the
6334 -- enumeration literal is temporarily changed to a function
6335 -- call for overloading analysis purposes.
6338 and then
6340 and then
6342 then
6347 -- Normally if the parent is a handled sequence of statements,
6348 -- then the current node must be a statement, and that is an
6349 -- appropriate place to insert a freeze node.
6353 -- An exception occurs when the sequence of statements is for
6354 -- an expander generated body that did not do the usual freeze
6355 -- all operation. In this case we usually want to freeze
6356 -- outside this body, not inside it, and we skip past the
6357 -- subprogram body that we are inside.
6360 declare
6364 begin
6365 -- Freeze the entity only when it is declared inside the
6366 -- body of the expander generated procedure. This case
6367 -- is recognized by the scope of the entity or its type,
6368 -- which is either the spec for some enclosing body, or
6369 -- (in the case of init_procs, for which there are no
6370 -- separate specs) the current scope.
6376 or else
6378 then
6384 then
6389 -- An expression function may act as a completion of
6390 -- a function declaration. As such, it can reference
6391 -- entities declared between the two views:
6393 -- Hidden []; -- 1
6394 -- function F return ...;
6395 -- private
6396 -- function Hidden return ...;
6397 -- function F return ... is (Hidden); -- 2
6399 -- Refering to the example above, freezing the expression
6400 -- of F (2) would place Hidden's freeze node (1) in the
6401 -- wrong place. Avoid explicit freezing and let the usual
6402 -- scenarios do the job - for example, reaching the end
6403 -- of the private declarations, or a call to F.
6406 N_Expression_Function
6407 then
6410 -- Freeze outside the body
6412 else
6418 -- Here if normal case where we are in handled statement
6419 -- sequence and want to do the insertion right there.
6421 else
6425 -- If parent is a body or a spec or a block, then the current node
6426 -- is a statement or declaration and we can insert the freeze node
6427 -- before it.
6429 when N_Block_Statement |
6430 N_Entry_Body |
6431 N_Package_Body |
6432 N_Package_Specification |
6433 N_Protected_Body |
6434 N_Subprogram_Body |
6437 -- The expander is allowed to define types in any statements list,
6438 -- so any of the following parent nodes also mark a freezing point
6439 -- if the actual node is in a list of statements or declarations.
6441 when N_Abortable_Part |
6442 N_Accept_Alternative |
6443 N_And_Then |
6444 N_Case_Statement_Alternative |
6445 N_Compilation_Unit_Aux |
6446 N_Conditional_Entry_Call |
6447 N_Delay_Alternative |
6448 N_Elsif_Part |
6449 N_Entry_Call_Alternative |
6450 N_Exception_Handler |
6451 N_Extended_Return_Statement |
6452 N_Freeze_Entity |
6453 N_If_Statement |
6454 N_Or_Else |
6455 N_Selective_Accept |
6456 N_Triggering_Alternative =>
6460 -- Freeze nodes produced by an expression coming from the Actions
6461 -- list of a N_Expression_With_Actions node must remain within the
6462 -- Actions list. Inserting the freeze nodes further up the tree
6463 -- may lead to use before declaration issues in the case of array
6464 -- types.
6469 then
6473 -- Note: N_Loop_Statement is a special case. A type that appears
6474 -- in the source can never be frozen in a loop (this occurs only
6475 -- because of a loop expanded by the expander), so we keep on
6476 -- going. Otherwise we terminate the search. Same is true of any
6477 -- entity which comes from source. (if they have predefined type,
6478 -- that type does not appear to come from source, but the entity
6479 -- should not be frozen here).
6485 -- For all other cases, keep looking at parents
6491 -- We fall through the case if we did not yet find the proper
6492 -- place in the free for inserting the freeze node, so climb.
6497 -- If the expression appears in a record or an initialization procedure,
6498 -- the freeze nodes are collected and attached to the current scope, to
6499 -- be inserted and analyzed on exit from the scope, to insure that
6500 -- generated entities appear in the correct scope. If the expression is
6501 -- a default for a discriminant specification, the scope is still void.
6502 -- The expression can also appear in the discriminant part of a private
6503 -- or concurrent type.
6505 -- If the expression appears in a constrained subcomponent of an
6506 -- enclosing record declaration, the freeze nodes must be attached to
6507 -- the outer record type so they can eventually be placed in the
6508 -- enclosing declaration list.
6510 -- The other case requiring this special handling is if we are in a
6511 -- default expression, since in that case we are about to freeze a
6512 -- static type, and the freeze scope needs to be the outer scope, not
6513 -- the scope of the subprogram with the default parameter.
6515 -- For default expressions and other spec expressions in generic units,
6516 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
6517 -- placing them at the proper place, after the generic unit.
6520 or else Freeze_Outside
6525 then
6526 declare
6531 begin
6544 -- The current scope may be that of a constrained component of
6545 -- an enclosing record declaration, or of a loop of an enclosing
6546 -- quantified expression, which is above the current scope in the
6547 -- scope stack. Indeed in the context of a quantified expression,
6548 -- a scope is created and pushed above the current scope in order
6549 -- to emulate the loop-like behavior of the quantified expression.
6550 -- If the expression is within a top-level pragma, as for a pre-
6551 -- condition on a library-level subprogram, nothing to do.
6556 N_Quantified_Expression)
6557 then
6564 Freeze_Nodes;
6565 else
6575 -- Now we have the right place to do the freezing. First, a special
6576 -- adjustment, if we are in spec-expression analysis mode, these freeze
6577 -- actions must not be thrown away (normally all inserted actions are
6578 -- thrown away in this mode. However, the freeze actions are from static
6579 -- expressions and one of the important reasons we are doing this
6580 -- special analysis is to get these freeze actions. Therefore we turn
6581 -- off the In_Spec_Expression mode to propagate these freeze actions.
6582 -- This also means they get properly analyzed and expanded.
6586 -- Freeze the designated type of an allocator (RM 13.14(13))
6592 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
6593 -- the enumeration representation clause exception in the loop above.
6599 -- Freeze name if one is present (RM 13.14(11))
6605 -- Restore In_Spec_Expression flag
6610 -----------------------------
6611 -- Freeze_Fixed_Point_Type --
6612 -----------------------------
6614 -- Certain fixed-point types and subtypes, including implicit base types
6615 -- and declared first subtypes, have not yet set up a range. This is
6616 -- because the range cannot be set until the Small and Size values are
6617 -- known, and these are not known till the type is frozen.
6619 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
6620 -- whose bounds are unanalyzed real literals. This routine will recognize
6621 -- this case, and transform this range node into a properly typed range
6622 -- with properly analyzed and resolved values.
6640 -- Returns size of type with given bounds. Also leaves these
6641 -- bounds set as the current bounds of the Typ.
6643 -----------
6644 -- Fsize --
6645 -----------
6648 begin
6654 -- Start of processing for Freeze_Fixed_Point_Type
6656 begin
6657 -- If Esize of a subtype has not previously been set, set it now
6664 else
6669 -- Immediate return if the range is already analyzed. This means that
6670 -- the range is already set, and does not need to be computed by this
6671 -- routine.
6677 -- Immediate return if either of the bounds raises Constraint_Error
6681 then
6688 -- Ordinary fixed-point case
6692 -- For the ordinary fixed-point case, we are allowed to fudge the
6693 -- end-points up or down by small. Generally we prefer to fudge up,
6694 -- i.e. widen the bounds for non-model numbers so that the end points
6695 -- are included. However there are cases in which this cannot be
6696 -- done, and indeed cases in which we may need to narrow the bounds.
6697 -- The following circuit makes the decision.
6699 -- Note: our terminology here is that Incl_EP means that the bounds
6700 -- are widened by Small if necessary to include the end points, and
6701 -- Excl_EP means that the bounds are narrowed by Small to exclude the
6702 -- end-points if this reduces the size.
6704 -- Note that in the Incl case, all we care about is including the
6705 -- end-points. In the Excl case, we want to narrow the bounds as
6706 -- much as permitted by the RM, to give the smallest possible size.
6723 begin
6724 -- First step. Base types are required to be symmetrical. Right
6725 -- now, the base type range is a copy of the first subtype range.
6726 -- This will be corrected before we are done, but right away we
6727 -- need to deal with the case where both bounds are non-negative.
6728 -- In this case, we set the low bound to the negative of the high
6729 -- bound, to make sure that the size is computed to include the
6730 -- required sign. Note that we do not need to worry about the
6731 -- case of both bounds negative, because the sign will be dealt
6732 -- with anyway. Furthermore we can't just go making such a bound
6733 -- symmetrical, since in a twos-complement system, there is an
6734 -- extra negative value which could not be accommodated on the
6735 -- positive side.
6740 then
6745 -- Compute the fudged bounds. If the number is a model number,
6746 -- then we do nothing to include it, but we are allowed to backoff
6747 -- to the next adjacent model number when we exclude it. If it is
6748 -- not a model number then we straddle the two values with the
6749 -- model numbers on either side.
6755 else
6759 -- The low value excluding the end point is Small greater, but
6760 -- we do not do this exclusion if the low value is positive,
6761 -- since it can't help the size and could actually hurt by
6762 -- crossing the high bound.
6767 -- If the value went from negative to zero, then we have the
6768 -- case where Loval_Incl_EP is the model number just below
6769 -- zero, so we want to stick to the negative value for the
6770 -- base type to maintain the condition that the size will
6771 -- include signed values.
6775 then
6779 else
6783 -- Similar processing for upper bound and high value
6789 else
6795 else
6799 -- One further adjustment is needed. In the case of subtypes, we
6800 -- cannot go outside the range of the base type, or we get
6801 -- peculiarities, and the base type range is already set. This
6802 -- only applies to the Incl values, since clearly the Excl values
6803 -- are already as restricted as they are allowed to be.
6810 -- Get size including and excluding end points
6815 -- No need to exclude end-points if it does not reduce size
6825 -- Now we set the actual size to be used. We want to use the
6826 -- bounds fudged up to include the end-points but only if this
6827 -- can be done without violating a specifically given size
6828 -- size clause or causing an unacceptable increase in size.
6830 -- Case of size clause given
6834 -- Use the inclusive size only if it is consistent with
6835 -- the explicitly specified size.
6842 -- If the inclusive size is too large, we try excluding
6843 -- the end-points (will be caught later if does not work).
6845 else
6851 -- Case of size clause not given
6853 else
6854 -- If we have a base type whose corresponding first subtype
6855 -- has an explicit size that is large enough to include our
6856 -- end-points, then do so. There is no point in working hard
6857 -- to get a base type whose size is smaller than the specified
6858 -- size of the first subtype.
6864 then
6869 -- If excluding the end-points makes the size smaller and
6870 -- results in a size of 8,16,32,64, then we take the smaller
6871 -- size. For the 64 case, this is compulsory. For the other
6872 -- cases, it seems reasonable. We like to include end points
6873 -- if we can, but not at the expense of moving to the next
6874 -- natural boundary of size.
6878 then
6883 -- Otherwise we can definitely include the end points
6885 else
6891 -- One pathological case: normally we never fudge a low bound
6892 -- down, since it would seem to increase the size (if it has
6893 -- any effect), but for ranges containing single value, or no
6894 -- values, the high bound can be small too large. Consider:
6896 -- type t is delta 2.0**(-14)
6897 -- range 131072.0 .. 0;
6899 -- That lower bound is *just* outside the range of 32 bits, and
6900 -- does need fudging down in this case. Note that the bounds
6901 -- will always have crossed here, since the high bound will be
6902 -- fudged down if necessary, as in the case of:
6904 -- type t is delta 2.0**(-14)
6905 -- range 131072.0 .. 131072.0;
6907 -- So we detect the situation by looking for crossed bounds,
6908 -- and if the bounds are crossed, and the low bound is greater
6909 -- than zero, we will always back it off by small, since this
6910 -- is completely harmless.
6917 -- And of course, we need to do exactly the same parallel
6918 -- fudge for flat ranges in the negative region.
6931 -- For the decimal case, none of this fudging is required, since there
6932 -- are no end-point problems in the decimal case (the end-points are
6933 -- always included).
6935 else
6939 -- At this stage, the actual size has been calculated and the proper
6940 -- required bounds are stored in the low and high bounds.
6944 Error_Msg_N
6946 Typ);
6950 -- Check size against explicit given size
6956 Error_Msg_NE
6960 else
6964 -- Increase size to next natural boundary if no size clause given
6966 else
6973 else
6981 -- If we have a base type, then expand the bounds so that they extend to
6982 -- the full width of the allocated size in bits, to avoid junk range
6983 -- checks on intermediate computations.
6990 -- Final step is to reanalyze the bounds using the proper type
6991 -- and set the Corresponding_Integer_Value fields of the literals.
6997 -- Resolve with universal fixed if the base type, and the base type if
6998 -- it is a subtype. Note we can't resolve the base type with itself,
6999 -- that would be a reference before definition.
7003 else
7007 -- Set corresponding integer value for bound
7009 Set_Corresponding_Integer_Value
7012 -- Similar processing for high bound
7020 else
7024 Set_Corresponding_Integer_Value
7027 -- Set type of range to correspond to bounds
7031 -- Set Esize to calculated size if not set already
7037 -- Set RM_Size if not already set. If already set, check value
7039 declare
7042 begin
7047 Error_Msg_NE
7052 else
7058 ------------------
7059 -- Freeze_Itype --
7060 ------------------
7065 begin
7074 --------------------------
7075 -- Freeze_Static_Object --
7076 --------------------------
7081 -- Exception raised if the type of a static object cannot be made
7082 -- static. This happens if the type depends on non-global objects.
7085 -- Called to ensure that an expression used as part of a type definition
7086 -- is statically allocatable, which means that the expression type is
7087 -- statically allocatable, and the expression is either static, or a
7088 -- reference to a library level constant.
7091 -- Called to mark a type as static, checking that it is possible
7092 -- to set the type as static. If it is not possible, then the
7093 -- exception Cannot_Be_Static is raised.
7095 -----------------------------
7096 -- Ensure_Expression_Is_SA --
7097 -----------------------------
7102 begin
7114 then
7122 -----------------------
7123 -- Ensure_Type_Is_SA --
7124 -----------------------
7130 begin
7131 -- If type is library level, we are all set
7137 -- We are also OK if the type already marked as statically allocated,
7138 -- which means we processed it before.
7144 -- Mark type as statically allocated
7148 -- Check that it is safe to statically allocate this type
7166 declare
7170 begin
7182 else
7191 then
7210 else
7215 -- Start of processing for Freeze_Static_Object
7217 begin
7220 exception
7223 -- If the object that cannot be static is imported or exported, then
7224 -- issue an error message saying that this object cannot be imported
7225 -- or exported. If it has an address clause it is an overlay in the
7226 -- current partition and the static requirement is not relevant.
7227 -- Do not issue any error message when ignoring rep clauses.
7234 Error_Msg_N
7238 -- Otherwise must be exported, something is wrong if compiler
7239 -- is marking something as statically allocated which cannot be).
7242 Error_Msg_N
7247 -----------------------
7248 -- Freeze_Subprogram --
7249 -----------------------
7255 begin
7256 -- Subprogram may not have an address clause unless it is imported
7260 Error_Msg_N
7267 -- Reset the Pure indication on an imported subprogram unless an
7268 -- explicit Pure_Function pragma was present or the subprogram is an
7269 -- intrinsic. We do this because otherwise it is an insidious error
7270 -- to call a non-pure function from pure unit and have calls
7271 -- mysteriously optimized away. What happens here is that the Import
7272 -- can bypass the normal check to ensure that pure units call only pure
7273 -- subprograms.
7275 -- The reason for the intrinsic exception is that in general, intrinsic
7276 -- functions (such as shifts) are pure anyway. The only exceptions are
7277 -- the intrinsics in GNAT.Source_Info, and that unit is not marked Pure
7278 -- in any case, so no problem arises.
7284 then
7288 -- For non-foreign convention subprograms, this is where we create
7289 -- the extra formals (for accessibility level and constrained bit
7290 -- information). We delay this till the freeze point precisely so
7291 -- that we know the convention.
7297 -- If this is convention Ada and a Valued_Procedure, that's odd
7302 and then Warn_On_Export_Import
7303 then
7304 Error_Msg_N
7309 -- Case of foreign convention
7311 else
7314 -- For foreign conventions, warn about return of unconstrained array
7319 -- If no return type, probably some other error, e.g. a
7320 -- missing full declaration, so ignore.
7325 -- If the return type is generic, we have emitted a warning
7326 -- earlier on, and there is nothing else to check here. Specific
7327 -- instantiations may lead to erroneous behavior.
7332 -- Display warning if returning unconstrained array
7337 -- Check appropriate warning is enabled (should we check for
7338 -- Warnings (Off) on specific entities here, probably so???)
7340 and then Warn_On_Export_Import
7342 -- Exclude the VM case, since return of unconstrained arrays
7343 -- is properly handled in both the JVM and .NET cases.
7346 then
7347 Error_Msg_N
7354 -- If any of the formals for an exported foreign convention
7355 -- subprogram have defaults, then emit an appropriate warning since
7356 -- this is odd (default cannot be used from non-Ada code)
7361 if Warn_On_Export_Import
7363 then
7364 Error_Msg_N
7374 -- Pragma Inline_Always is disallowed for dispatching subprograms
7375 -- because the address of such subprograms is saved in the dispatch
7376 -- table to support dispatching calls, and dispatching calls cannot
7377 -- be inlined. This is consistent with the restriction against using
7378 -- 'Access or 'Address on an Inline_Always subprogram.
7382 then
7383 Error_Msg_N
7387 -- Because of the implicit representation of inherited predefined
7388 -- operators in the front-end, the overriding status of the operation
7389 -- may be affected when a full view of a type is analyzed, and this is
7390 -- not captured by the analysis of the corresponding type declaration.
7391 -- Therefore the correctness of a not-overriding indicator must be
7392 -- rechecked when the subprogram is frozen.
7396 then
7401 ----------------------
7402 -- Is_Fully_Defined --
7403 ----------------------
7406 begin
7415 then
7416 -- Verify that the record type has no components with private types
7417 -- without completion.
7419 declare
7422 begin
7434 -- For the designated type of an access to subprogram, all types in
7435 -- the profile must be fully defined.
7438 declare
7441 begin
7454 else
7460 ---------------------------------
7461 -- Process_Default_Expressions --
7462 ---------------------------------
7464 procedure Process_Default_Expressions
7467 is
7474 begin
7477 -- A subprogram instance and its associated anonymous subprogram share
7478 -- their signature. The default expression functions are defined in the
7479 -- wrapper packages for the anonymous subprogram, and should not be
7480 -- generated again for the instance.
7485 then
7493 -- We work with a copy of the default expression because we
7494 -- do not want to disturb the original, since this would mess
7495 -- up the conformance checking.
7499 -- The analysis of the expression may generate insert actions,
7500 -- which of course must not be executed. We wrap those actions
7501 -- in a procedure that is not called, and later on eliminated.
7502 -- The following cases have no side-effects, and are analyzed
7503 -- directly.
7507 N_Integer_Literal,
7508 N_Character_Literal,
7509 N_String_Literal,
7510 N_Real_Literal)
7514 then
7515 -- If there is no default function, we must still do a full
7516 -- analyze call on the default value, to ensure that all error
7517 -- checks are performed, e.g. those associated with static
7518 -- evaluation. Note: this branch will always be taken if the
7519 -- analyzer is turned off (but we still need the error checks).
7521 -- Note: the setting of parent here is to meet the requirement
7522 -- that we can only analyze the expression while attached to
7523 -- the tree. Really the requirement is that the parent chain
7524 -- be set, we don't actually need to be in the tree.
7529 -- Default expressions are resolved with their own type if the
7530 -- context is generic, to avoid anomalies with private types.
7534 else
7538 -- If that resolved expression will raise constraint error,
7539 -- then flag the default value as raising constraint error.
7540 -- This allows a proper error message on the calls.
7546 -- If the default is a parameterless call, we use the name of
7547 -- the called function directly, and there is no body to build.
7551 then
7554 -- Else construct and analyze the body of a wrapper procedure
7555 -- that contains an object declaration to hold the expression.
7556 -- Given that this is done only to complete the analysis, it
7557 -- simpler to build a procedure than a function which might
7558 -- involve secondary stack expansion.
7560 else
7563 Dbody :=
7565 Specification =>
7572 Object_Definition =>
7576 Handled_Statement_Sequence =>
7593 ----------------------------------------
7594 -- Set_Component_Alignment_If_Not_Set --
7595 ----------------------------------------
7598 begin
7599 -- Ignore if not base type, subtypes don't need anything
7605 -- Do not override existing representation
7616 else
7617 Set_Component_Alignment
7623 --------------------------
7624 -- Set_SSO_From_Default --
7625 --------------------------
7628 begin
7631 then
7633 or else
7636 -- For a record type, if native bit order is specified explicitly,
7637 -- then never set reverse SSO from default.
7639 and then not
7643 then
7644 -- If flags cause reverse storage order, then set the result. Note
7645 -- that we would have ignored the pragma setting the non default
7646 -- storage order in any case, hence the assertion at this point.
7651 -- For a record type, also set reversed bit order. Note that if
7652 -- a bit order has been specified explicitly, then this is a
7653 -- no-op, as per the guard above.
7662 ------------------
7663 -- Undelay_Type --
7664 ------------------
7667 begin
7671 -- Since we don't want T to have a Freeze_Node, we don't want its
7672 -- Full_View or Corresponding_Record_Type to have one either.
7674 -- ??? Fundamentally, this whole handling is unpleasant. What we really
7675 -- want is to be sure that for an Itype that's part of record R and is a
7676 -- subtype of type T, that it's frozen after the later of the freeze
7677 -- points of R and T. We have no way of doing that directly, so what we
7678 -- do is force most such Itypes to be frozen as part of freezing R via
7679 -- this procedure and only delay the ones that need to be delayed
7680 -- (mostly the designated types of access types that are defined as part
7681 -- of the record).
7687 then
7695 then
7700 ------------------
7701 -- Warn_Overlay --
7702 ------------------
7704 procedure Warn_Overlay
7708 is
7710 -- The object to which the address clause applies
7716 begin
7717 -- No warning if address clause overlay warnings are off
7723 -- No warning if there is an explicit initialization
7731 -- We only give the warning for non-imported entities of a type for
7732 -- which a non-null base init proc is defined, or for objects of access
7733 -- types with implicit null initialization, or when Normalize_Scalars
7734 -- applies and the type is scalar or a string type (the latter being
7735 -- tested for because predefined String types are initialized by inline
7736 -- code rather than by an init_proc). Note that we do not give the
7737 -- warning for Initialize_Scalars, since we suppressed initialization
7738 -- in this case. Also, do not warn if Suppress_Initialization is set.
7748 then
7751 then
7756 then
7763 then
7770 -- A function call (most likely to To_Address) is probably not an
7771 -- overlay, so skip warning. Ditto if the function call was inlined
7772 -- and transformed into an entity.
7780 -- If a pragma Import follows, we assume that it is for the current
7781 -- target of the address clause, and skip the warning.
7786 then
7792 Error_Msg_N
7794 Nam);
7795 else
7796 Error_Msg_N
7798 Nam);
7801 -- Add friendly warning if initialization comes from a packed array
7802 -- component.
7805 declare
7808 begin
7813 then
7817 then
7818 Error_Msg_NE
7823 else
7830 Error_Msg_N
7833 Nam);