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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) 1992-2008, 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 2, 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 COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
21 -- --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 -- --
25 ------------------------------------------------------------------------------
68 -----------------------
69 -- Local Subprograms --
70 -----------------------
73 -- Typ is a type that is being frozen. If no size clause is given,
74 -- but a default Esize has been computed, then this default Esize is
75 -- adjusted up if necessary to be consistent with a given alignment,
76 -- but never to a value greater than Long_Long_Integer'Size. This
77 -- is used for all discrete types and for fixed-point types.
79 procedure Build_And_Analyze_Renamed_Body
83 -- Build body for a renaming declaration, insert in tree and analyze
86 -- Apply legality checks to address clauses for object declarations,
87 -- at the point the object is frozen.
90 -- E is a base type. If E is tagged or has a component that is aliased
91 -- or tagged or contains something this is aliased or tagged, set
92 -- Strict_Alignment.
96 -- If E is a fixed-point or discrete type, then all the necessary work
97 -- to freeze it is completed except for possible setting of the flag
98 -- Is_Unsigned_Type, which is done by this procedure. The call has no
99 -- effect if the entity E is not a discrete or fixed-point type.
101 procedure Freeze_And_Append
105 -- Freezes Ent using Freeze_Entity, and appends the resulting list of
106 -- nodes to Result, modifying Result from No_List if necessary.
109 -- Freeze enumeration type. The Esize field is set as processing
110 -- proceeds (i.e. set by default when the type is declared and then
111 -- adjusted by rep clauses. What this procedure does is to make sure
112 -- that if a foreign convention is specified, and no specific size
113 -- is given, then the size must be at least Integer'Size.
116 -- If an object is frozen which has Is_Statically_Allocated set, then
117 -- all referenced types must also be marked with this flag. This routine
118 -- is in charge of meeting this requirement for the object entity E.
121 -- Perform freezing actions for a subprogram (create extra formals,
122 -- and set proper default mechanism values). Note that this routine
123 -- is not called for internal subprograms, for which neither of these
124 -- actions is needed (or desirable, we do not want for example to have
125 -- these extra formals present in initialization procedures, where they
126 -- would serve no purpose). In this call E is either a subprogram or
127 -- a subprogram type (i.e. an access to a subprogram).
130 -- True if T is not private and has no private components, or has a full
131 -- view. Used to determine whether the designated type of an access type
132 -- should be frozen when the access type is frozen. This is done when an
133 -- allocator is frozen, or an expression that may involve attributes of
134 -- the designated type. Otherwise freezing the access type does not freeze
135 -- the designated type.
138 -- For a tagged type, generate implicit references to its primitive
139 -- operations, for source navigation.
141 procedure Process_Default_Expressions
144 -- This procedure is called for each subprogram to complete processing
145 -- of default expressions at the point where all types are known to be
146 -- frozen. The expressions must be analyzed in full, to make sure that
147 -- all error processing is done (they have only been pre-analyzed). If
148 -- the expression is not an entity or literal, its analysis may generate
149 -- code which must not be executed. In that case we build a function
150 -- body to hold that code. This wrapper function serves no other purpose
151 -- (it used to be called to evaluate the default, but now the default is
152 -- inlined at each point of call).
155 -- Typ is a record or array type that is being frozen. This routine
156 -- sets the default component alignment from the scope stack values
157 -- if the alignment is otherwise not specified.
160 -- As each entity is frozen, this routine is called to deal with the
161 -- setting of Debug_Info_Needed for the entity. This flag is set if
162 -- the entity comes from source, or if we are in Debug_Generated_Code
163 -- mode or if the -gnatdV debug flag is set. However, it never sets
164 -- the flag if Debug_Info_Off is set. This procedure also ensures that
165 -- subsidiary entities have the flag set as required.
168 -- T is a type of a component that we know to be an Itype.
169 -- We don't want this to have a Freeze_Node, so ensure it doesn't.
170 -- Do the same for any Full_View or Corresponding_Record_Type.
172 procedure Warn_Overlay
176 -- Expr is the expression for an address clause for entity Nam whose type
177 -- is Typ. If Typ has a default initialization, and there is no explicit
178 -- initialization in the source declaration, check whether the address
179 -- clause might cause overlaying of an entity, and emit a warning on the
180 -- side effect that the initialization will cause.
182 -------------------------------
183 -- Adjust_Esize_For_Alignment --
184 -------------------------------
189 begin
195 then
201 ------------------------------------
202 -- Build_And_Analyze_Renamed_Body --
203 ------------------------------------
205 procedure Build_And_Analyze_Renamed_Body
209 is
211 begin
218 ------------------------
219 -- Build_Renamed_Body --
220 ------------------------
222 function Build_Renamed_Body
225 is
227 -- We use for the source location of the renamed body, the location
228 -- of the spec entity. It might seem more natural to use the location
229 -- of the renaming declaration itself, but that would be wrong, since
230 -- then the body we create would look as though it was created far
231 -- too late, and this could cause problems with elaboration order
232 -- analysis, particularly in connection with instantiations.
247 -- If the renamed entity is a primitive operation given in prefix form,
248 -- the prefix is the target object and it has to be added as the first
249 -- actual in the generated call.
251 begin
252 -- Determine the entity being renamed, which is the target of the call
253 -- statement. If the name is an explicit dereference, this is a renaming
254 -- of a subprogram type rather than a subprogram. The name itself is
255 -- fully analyzed.
266 else
273 else
279 -- If the renamed entity is a predefined operator, retain full name
280 -- to ensure its visibility.
284 then
286 else
290 else
293 and then
296 then
298 -- Retrieve the target object, to be added as a first actual
299 -- in the call.
304 else
308 -- The original name may have been overloaded, but
309 -- is fully resolved now.
314 -- For simple renamings, subsequent calls can be expanded directly as
315 -- called to the renamed entity. The body must be generated in any case
316 -- for calls they may appear elsewhere.
321 then
325 -- The body generated for this renaming is an internal artifact, and
326 -- does not constitute a freeze point for the called entity.
333 declare
337 begin
339 -- The controlling formal may be an access parameter, or the
340 -- actual may be an access value, so adjust accordingly.
344 then
345 Actuals := New_List
350 then
351 Actuals := New_List
355 else
363 else
374 -- If the renamed entity is an entry, inherit its profile. For other
375 -- renamings as bodies, both profiles must be subtype conformant, so it
376 -- is not necessary to replace the profile given in the declaration.
377 -- However, default values that are aggregates are rewritten when
378 -- partially analyzed, so we recover the original aggregate to insure
379 -- that subsequent conformity checking works. Similarly, if the default
380 -- expression was constant-folded, recover the original expression.
392 N_Access_Definition
393 then
401 then
412 -- If the renamed entity is a function, the generated body contains a
413 -- return statement. Otherwise, build a procedure call. If the entity is
414 -- an entry, subsequent analysis of the call will transform it into the
415 -- proper entry or protected operation call. If the renamed entity is
416 -- a character literal, return it directly.
422 then
423 Call_Node :=
425 Expression =>
431 Call_Node :=
436 Call_Node :=
440 else
441 Call_Node :=
447 -- Create entities for subprogram body and formals
461 Body_Node :=
465 Handled_Statement_Sequence =>
475 -- Link the body to the entity whose declaration it completes. If
476 -- the body is analyzed when the renamed entity is frozen, it may
477 -- be necessary to restore the proper scope (see package Exp_Ch13).
481 then
483 else
490 --------------------------
491 -- Check_Address_Clause --
492 --------------------------
500 begin
504 -- If we have no initialization of any kind, then we don't need to
505 -- place any restrictions on the address clause, because the object
506 -- will be elaborated after the address clause is evaluated. This
507 -- happens if the declaration has no initial expression, or the type
508 -- has no implicit initialization, or the object is imported.
510 -- The same holds for all initialized scalar types and all access
511 -- types. Packed bit arrays of size up to 64 are represented using a
512 -- modular type with an initialization (to zero) and can be processed
513 -- like other initialized scalar types.
515 -- If the type is controlled, code to attach the object to a
516 -- finalization chain is generated at the point of declaration,
517 -- and therefore the elaboration of the object cannot be delayed:
518 -- the address expression must be a constant.
522 and then
526 or else
530 or else
533 or else
535 and then
537 then
540 -- Otherwise, we require the address clause to be constant because
541 -- the call to the initialization procedure (or the attach code) has
542 -- to happen at the point of the declaration.
544 else
551 then
557 -----------------------------
558 -- Check_Compile_Time_Size --
559 -----------------------------
564 -- Sets the compile time known size (32 bits or less) in the Esize
565 -- field, of T checking for a size clause that was given which attempts
566 -- to give a smaller size.
569 -- Recursive function that does all the work
572 -- If T is a constrained subtype, its size is not known if any of its
573 -- discriminant constraints is not static and it is not a null record.
574 -- The test is conservative and doesn't check that the components are
575 -- in fact constrained by non-static discriminant values. Could be made
576 -- more precise ???
578 --------------------
579 -- Set_Small_Size --
580 --------------------
583 begin
590 Error_Msg_NE
598 -- Set sizes if not set already
600 else
611 ----------------
612 -- Size_Known --
613 ----------------
622 begin
626 -- Always True for scalar types. This is true even for generic formal
627 -- scalar types. We used to return False in the latter case, but the
628 -- size is known at compile time, even in the template, we just do
629 -- not know the exact size but that's not the point of this routine.
633 then
636 -- Array types
640 -- String literals always have known size, and we can set it
647 -- Unconstrained types never have known at compile time size
652 -- Don't do any recursion on type with error posted, since we may
653 -- have a malformed type that leads us into a loop.
658 -- Otherwise if component size unknown, then array size unknown
664 -- Check for all indexes static, and also compute possible size
665 -- (in case it is less than 32 and may be packable).
667 declare
671 begin
680 else
688 then
691 else
696 else
708 -- Access types always have known at compile time sizes
713 -- For non-generic private types, go to underlying type if present
718 then
719 -- Don't do any recursion on type with error posted, since we may
720 -- have a malformed type that leads us into a loop.
724 else
728 -- Record types
732 -- A class-wide type is never considered to have a known size
737 -- A subtype of a variant record must not have non-static
738 -- discriminanted components.
742 then
745 -- Don't do any recursion on type with error posted, since we may
746 -- have a malformed type that leads us into a loop.
752 -- Now look at the components of the record
754 declare
755 -- The following two variables are used to keep track of the
756 -- size of packed records if we can tell the size of the packed
757 -- record in the front end. Packed_Size_Known is True if so far
758 -- we can figure out the size. It is initialized to True for a
759 -- packed record, unless the record has discriminants. The
760 -- reason we eliminate the discriminated case is that we don't
761 -- know the way the back end lays out discriminated packed
762 -- records. If Packed_Size_Known is True, then Packed_Size is
763 -- the size in bits so far.
771 begin
772 -- Test for variant part present
778 N_Record_Definition
782 then
783 -- If variant part is present, and type is unconstrained,
784 -- then we must have defaulted discriminants, or a size
785 -- clause must be present for the type, or else the size
786 -- is definitely not known at compile time.
789 and then
790 No (Discriminant_Default_Value
793 then
798 -- Loop through components
804 -- We do not know the packed size if there is a component
805 -- clause present (we possibly could, but this would only
806 -- help in the case of a record with partial rep clauses.
807 -- That's because in the case of full rep clauses, the
808 -- size gets figured out anyway by a different circuit).
814 -- We need to identify a component that is an array where
815 -- the index type is an enumeration type with non-standard
816 -- representation, and some bound of the type depends on a
817 -- discriminant.
819 -- This is because gigi computes the size by doing a
820 -- substitution of the appropriate discriminant value in
821 -- the size expression for the base type, and gigi is not
822 -- clever enough to evaluate the resulting expression (which
823 -- involves a call to rep_to_pos) at compile time.
825 -- It would be nice if gigi would either recognize that
826 -- this expression can be computed at compile time, or
827 -- alternatively figured out the size from the subtype
828 -- directly, where all the information is at hand ???
832 then
833 declare
841 begin
848 then
854 then
859 then
869 -- Clearly size of record is not known if the size of one of
870 -- the components is not known.
876 -- Accumulate packed size if possible
880 -- We can only deal with elementary types, since for
881 -- non-elementary components, alignment enters into the
882 -- picture, and we don't know enough to handle proper
883 -- alignment in this context. Packed arrays count as
884 -- elementary if the representation is a modular type.
889 and then Is_Modular_Integer_Type
891 then
892 -- If RM_Size is known and static, then we can
893 -- keep accumulating the packed size.
897 -- A little glitch, to be removed sometime ???
898 -- gigi does not understand zero sizes yet.
903 -- Normal case where we can keep accumulating the
904 -- packed array size.
906 else
910 -- If we have a field whose RM_Size is not known then
911 -- we can't figure out the packed size here.
913 else
917 -- If we have a non-elementary type we can't figure out
918 -- the packed array size (alignment issues).
920 else
935 -- All other cases, size not known at compile time
937 else
942 -------------------------------------
943 -- Static_Discriminated_Components --
944 -------------------------------------
946 function Static_Discriminated_Components
948 is
951 begin
955 then
969 -- Start of processing for Check_Compile_Time_Size
971 begin
975 -----------------------------
976 -- Check_Debug_Info_Needed --
977 -----------------------------
980 begin
985 or else Debug_Generated_Code
986 or else Debug_Flag_VV
988 then
993 ----------------------------
994 -- Check_Strict_Alignment --
995 ----------------------------
1000 begin
1019 then
1029 -------------------------
1030 -- Check_Unsigned_Type --
1031 -------------------------
1038 begin
1043 -- Do not attempt to analyze case where range was in error
1049 -- The situation that is non trivial is something like
1051 -- subtype x1 is integer range -10 .. +10;
1052 -- subtype x2 is x1 range 0 .. V1;
1053 -- subtype x3 is x2 range V2 .. V3;
1054 -- subtype x4 is x3 range V4 .. V5;
1056 -- where Vn are variables. Here the base type is signed, but we still
1057 -- know that x4 is unsigned because of the lower bound of x2.
1059 -- The only way to deal with this is to look up the ancestor chain
1062 loop
1077 else
1080 -- If no ancestor had a static lower bound, go to base type
1084 -- Note: the reason we still check for a compile time known
1085 -- value for the base type is that at least in the case of
1086 -- generic formals, we can have bounds that fail this test,
1087 -- and there may be other cases in error situations.
1099 then
1109 -----------------------------
1110 -- Expand_Atomic_Aggregate --
1111 -----------------------------
1118 begin
1123 then
1124 Temp :=
1128 New_N :=
1138 -- To prevent the temporary from being constant-folded (which would
1139 -- lead to the same piecemeal assignment on the original target)
1140 -- indicate to the back-end that the temporary is a variable with
1141 -- real storage. See description of this flag in Einfo, and the notes
1142 -- on N_Assignment_Statement and N_Object_Declaration in Sinfo.
1148 ----------------
1149 -- Freeze_All --
1150 ----------------
1152 -- Note: the easy coding for this procedure would be to just build a
1153 -- single list of freeze nodes and then insert them and analyze them
1154 -- all at once. This won't work, because the analysis of earlier freeze
1155 -- nodes may recursively freeze types which would otherwise appear later
1156 -- on in the freeze list. So we must analyze and expand the freeze nodes
1157 -- as they are generated.
1165 -- This is the internal recursive routine that does freezing of entities
1166 -- (but NOT the analysis of default expressions, which should not be
1167 -- recursive, we don't want to analyze those till we are sure that ALL
1168 -- the types are frozen).
1170 --------------------
1171 -- Freeze_All_Ent --
1172 --------------------
1174 procedure Freeze_All_Ent
1177 is
1183 -- If freeze nodes are present, insert and analyze, and reset cursor
1184 -- for next insertion.
1186 -------------------
1187 -- Process_Flist --
1188 -------------------
1191 begin
1198 else
1204 -- Start or processing for Freeze_All_Ent
1206 begin
1210 -- If the entity is an inner package which is not a package
1211 -- renaming, then its entities must be frozen at this point. Note
1212 -- that such entities do NOT get frozen at the end of the nested
1213 -- package itself (only library packages freeze).
1215 -- Same is true for task declarations, where anonymous records
1216 -- created for entry parameters must be frozen.
1222 then
1232 and then
1234 or else
1236 then
1239 End_Scope;
1241 -- For a derived tagged type, we must ensure that all the
1242 -- primitive operations of the parent have been frozen, so that
1243 -- their addresses will be in the parent's dispatch table at the
1244 -- point it is inherited.
1250 then
1251 declare
1258 begin
1266 then
1268 Process_Flist;
1278 Process_Flist;
1281 -- If an incomplete type is still not frozen, this may be a
1282 -- premature freezing because of a body declaration that follows.
1283 -- Indicate where the freezing took place.
1285 -- If the freezing is caused by the end of the current declarative
1286 -- part, it is a Taft Amendment type, and there is no error.
1290 then
1291 declare
1294 begin
1301 and then
1303 then
1305 Error_Msg_NE
1316 -- Start of processing for Freeze_All
1318 begin
1321 -- Now that all types are frozen, we can deal with default expressions
1322 -- that require us to build a default expression functions. This is the
1323 -- point at which such functions are constructed (after all types that
1324 -- might be used in such expressions have been frozen).
1326 -- We also add finalization chains to access types whose designated
1327 -- types are controlled. This is normally done when freezing the type,
1328 -- but this misses recursive type definitions where the later members
1329 -- of the recursion introduce controlled components.
1331 -- Loop through entities
1349 and then
1351 = N_Subprogram_Renaming_Declaration
1352 then
1353 Build_And_Analyze_Renamed_Body
1359 and then
1361 or else
1363 then
1364 declare
1366 begin
1373 then
1386 then
1394 -----------------------
1395 -- Freeze_And_Append --
1396 -----------------------
1398 procedure Freeze_And_Append
1402 is
1404 begin
1408 else
1414 -------------------
1415 -- Freeze_Before --
1416 -------------------
1420 begin
1426 -------------------
1427 -- Freeze_Entity --
1428 -------------------
1440 -- Check that an Access or Unchecked_Access attribute with a prefix
1441 -- which is the current instance type can only be applied when the type
1442 -- is limited.
1445 -- If Loc is a freeze_entity that appears after the last declaration
1446 -- in the scope, inhibit error messages on late completion.
1449 -- Freeze each component, handle some representation clauses, and freeze
1450 -- primitive operations if this is a tagged type.
1452 ----------------------------
1453 -- After_Last_Declaration --
1454 ----------------------------
1458 begin
1464 else
1467 else
1472 ----------------------------
1473 -- Check_Current_Instance --
1474 ----------------------------
1484 -- Process routine to apply check to given node
1486 -------------
1487 -- Process --
1488 -------------
1491 begin
1495 or else
1500 then
1501 Error_Msg_N
1504 else
1514 -- Start of processing for Check_Current_Instance
1516 begin
1517 -- In Ada95, the (imprecise) rule is that the current instance of a
1518 -- limited type is aliased. In Ada2005, limitedness must be explicit:
1519 -- either a tagged type, or a limited record.
1522 and then
1525 then
1530 then
1533 else
1538 ------------------------
1539 -- Freeze_Record_Type --
1540 ------------------------
1552 -- Set True if we find at least one component with no component
1553 -- clause (used to warn about useless Pack pragmas).
1556 -- Set True if we find at least one component with a component
1557 -- clause (used to warn about useless Bit_Order pragmas).
1560 -- If N is an allocator, possibly wrapped in one or more level of
1561 -- qualified expression(s), return the inner allocator node, else
1562 -- return Empty.
1565 -- If the component subtype is an access to a constrained subtype of
1566 -- an already frozen type, make the subtype frozen as well. It might
1567 -- otherwise be frozen in the wrong scope, and a freeze node on
1568 -- subtype has no effect. Similarly, if the component subtype is a
1569 -- regular (not protected) access to subprogram, set the anonymous
1570 -- subprogram type to frozen as well, to prevent an out-of-scope
1571 -- freeze node at some eventual point of call. Protected operations
1572 -- are handled elsewhere.
1574 ---------------------
1575 -- Check_Allocator --
1576 ---------------------
1580 begin
1582 loop
1587 else
1593 -----------------
1594 -- Check_Itype --
1595 -----------------
1600 begin
1603 then
1606 -- In addition, add an Itype_Reference to ensure that the
1607 -- access subtype is elaborated early enough. This cannot be
1608 -- done if the subtype may depend on discriminants.
1613 then
1619 else
1626 then
1631 -- Start of processing for Freeze_Record_Type
1633 begin
1634 -- If this is a subtype of a controlled type, declared without a
1635 -- constraint, the _controller may not appear in the component list
1636 -- if the parent was not frozen at the point of subtype declaration.
1637 -- Inherit the _controller component now.
1641 then
1644 then
1647 -- If this is an internal type without a declaration, as for
1648 -- record component, the base type may not yet be frozen, and its
1649 -- controller has not been created. Add an explicit freeze node
1650 -- for the itype, so it will be frozen after the base type. This
1651 -- freeze node is used to communicate with the expander, in order
1652 -- to create the controller for the enclosing record, and it is
1653 -- deleted afterwards (see exp_ch3). It must not be created when
1654 -- expansion is off, because it might appear in the wrong context
1655 -- for the back end.
1659 and then
1661 N_Component_Declaration
1662 and then Expander_Active
1663 then
1668 -- Freeze components and embedded subtypes
1674 -- First handle the (real) component case
1678 then
1679 declare
1682 begin
1683 -- Freezing a record type freezes the type of each of its
1684 -- components. However, if the type of the component is
1685 -- part of this record, we do not want or need a separate
1686 -- Freeze_Node. Note that Is_Itype is wrong because that's
1687 -- also set in private type cases. We also can't check for
1688 -- the Scope being exactly Rec because of private types and
1689 -- record extensions.
1694 then
1700 -- Check for error of component clause given for variable
1701 -- sized type. We have to delay this test till this point,
1702 -- since the component type has to be frozen for us to know
1703 -- if it is variable length. We omit this test in a generic
1704 -- context, it will be applied at instantiation time.
1712 elsif not
1713 Size_Known_At_Compile_Time
1715 then
1716 Error_Msg_N
1721 else
1725 -- Case of component requires byte alignment
1729 -- Set the enclosing record to also require byte align
1733 -- Check for component clause that is inconsistent with
1734 -- the required byte boundary alignment.
1739 then
1740 Error_Msg_N
1746 -- If component clause is present, then deal with the non-
1747 -- default bit order case for Ada 95 mode. The required
1748 -- processing for Ada 2005 mode is handled separately after
1749 -- processing all components.
1751 -- We only do this processing for the base type, and in
1752 -- fact that's important, since otherwise if there are
1753 -- record subtypes, we could reverse the bits once for
1754 -- each subtype, which would be incorrect.
1760 then
1761 declare
1774 begin
1775 -- Cases where field goes over storage unit boundary
1779 -- Allow multi-byte field but generate warning
1783 then
1784 Error_Msg_N
1789 Error_Msg_N
1792 else
1793 Error_Msg_N
1798 -- Do not allow non-contiguous field
1800 else
1801 Error_Msg_N
1804 Error_Msg_N
1807 Error_Msg_N
1812 -- Case where field fits in one storage unit
1814 else
1815 -- Give warning if suspicious component clause
1818 and then Warn_On_Reverse_Bit_Order
1819 then
1820 Error_Msg_N
1823 Error_Msg_Uint_1 :=
1825 System_Storage_Unit;
1826 Error_Msg_N
1831 -- Here is where we fix up the Component_Bit_Offset
1832 -- value to account for the reverse bit order.
1833 -- Some examples of what needs to be done are:
1835 -- First_Bit .. Last_Bit Component_Bit_Offset
1836 -- old new old new
1838 -- 0 .. 0 7 .. 7 0 7
1839 -- 0 .. 1 6 .. 7 0 6
1840 -- 0 .. 2 5 .. 7 0 5
1841 -- 0 .. 7 0 .. 7 0 4
1843 -- 1 .. 1 6 .. 6 1 6
1844 -- 1 .. 4 3 .. 6 1 3
1845 -- 4 .. 7 0 .. 3 4 0
1847 -- The general rule is that the first bit is
1848 -- is obtained by subtracting the old ending bit
1849 -- from storage_unit - 1.
1851 Set_Component_Bit_Offset
1857 Set_Normalized_First_Bit
1860 System_Storage_Unit);
1867 -- If the component is an Itype with Delayed_Freeze and is either
1868 -- a record or array subtype and its base type has not yet been
1869 -- frozen, we must remove this from the entity list of this
1870 -- record and put it on the entity list of the scope of its base
1871 -- type. Note that we know that this is not the type of a
1872 -- component since we cleared Has_Delayed_Freeze for it in the
1873 -- previous loop. Thus this must be the Designated_Type of an
1874 -- access type, which is the type of a component.
1882 then
1883 declare
1887 begin
1888 -- We have a pretty bad kludge here. Suppose Rec is subtype
1889 -- being defined in a subprogram that's created as part of
1890 -- the freezing of Rec'Base. In that case, we know that
1891 -- Comp'Base must have already been frozen by the time we
1892 -- get to elaborate this because Gigi doesn't elaborate any
1893 -- bodies until it has elaborated all of the declarative
1894 -- part. But Is_Frozen will not be set at this point because
1895 -- we are processing code in lexical order.
1897 -- We detect this case by going up the Scope chain of Rec
1898 -- and seeing if we have a subprogram scope before reaching
1899 -- the top of the scope chain or that of Comp'Base. If we
1900 -- do, then mark that Comp'Base will actually be frozen. If
1901 -- so, we merely undelay it.
1917 else
1920 else
1924 -- Insert in entity list of scope of base type (which
1925 -- must be an enclosing scope, because still unfrozen).
1931 -- If the component is an access type with an allocator as default
1932 -- value, the designated type will be frozen by the corresponding
1933 -- expression in init_proc. In order to place the freeze node for
1934 -- the designated type before that for the current record type,
1935 -- freeze it now.
1937 -- Same process if the component is an array of access types,
1938 -- initialized with an aggregate. If the designated type is
1939 -- private, it cannot contain allocators, and it is premature
1940 -- to freeze the type, so we check for this as well.
1945 then
1946 declare
1950 begin
1953 -- If component is pointer to a classwide type, freeze
1954 -- the specific type in the expression being allocated.
1955 -- The expression may be a subtype indication, in which
1956 -- case freeze the subtype mark.
1958 if Is_Class_Wide_Type
1960 then
1962 Freeze_And_Append
1964 elsif
1966 then
1967 Freeze_And_Append
1975 else
1976 Freeze_And_Append
1984 then
1993 and then Is_Fully_Defined
1995 then
1996 Freeze_And_Append
1997 (Designated_Type
2005 -- Deal with pragma Bit_Order
2009 ADC :=
2011 Error_Msg_N
2013 Error_Msg_N
2016 -- Here is where we do Ada 2005 processing for bit order (the Ada
2017 -- 95 case was already taken care of above).
2024 -- Set OK_To_Reorder_Components depending on debug flags
2028 then
2030 or else
2032 then
2037 -- Check for useless pragma Pack when all components placed. We only
2038 -- do this check for record types, not subtypes, since a subtype may
2039 -- have all its components placed, and it still makes perfectly good
2040 -- sense to pack other subtypes or the parent type. We do not give
2041 -- this warning if Optimize_Alignment is set to Space, since the
2042 -- pragma Pack does have an effect in this case (it always resets
2043 -- the alignment to one).
2047 and then not Unplaced_Component
2049 then
2050 -- Reset packed status. Probably not necessary, but we do it so
2051 -- that there is no chance of the back end doing something strange
2052 -- with this redundant indication of packing.
2056 -- Give warning if redundant constructs warnings on
2059 Error_Msg_N
2065 -- If this is the record corresponding to a remote type, freeze the
2066 -- remote type here since that is what we are semantically freezing.
2067 -- This prevents the freeze node for that type in an inner scope.
2069 -- Also, Check for controlled components and unchecked unions.
2070 -- Finally, enforce the restriction that access attributes with a
2071 -- current instance prefix can only apply to limited types.
2075 Freeze_And_Append
2085 and then Present
2087 and then Has_Controlled_Component
2089 then
2100 -- Scan component declaration for likely misuses of current
2101 -- instance, either in a constraint or a default expression.
2112 -- For first subtypes, check if there are any fixed-point fields with
2113 -- component clauses, where we must check the size. This is not done
2114 -- till the freeze point, since for fixed-point types, we do not know
2115 -- the size until the type is frozen. Similar processing applies to
2116 -- bit packed arrays.
2124 or else
2126 then
2127 Check_Size
2131 Junk);
2138 -- Generate warning for applying C or C++ convention to a record
2139 -- with discriminants. This is suppressed for the unchecked union
2140 -- case, since the whole point in this case is interface C. We also
2141 -- do not generate this within instantiations, since we will have
2142 -- generated a message on the template.
2147 or else
2150 and then not In_Instance
2153 then
2154 declare
2158 begin
2163 Error_Msg_N
2165 else
2166 Error_Msg_N
2170 Error_Msg_NE
2177 -- Start of processing for Freeze_Entity
2179 begin
2180 -- We are going to test for various reasons why this entity need not be
2181 -- frozen here, but in the case of an Itype that's defined within a
2182 -- record, that test actually applies to the record.
2188 then
2192 -- Do not freeze if already frozen since we only need one freeze node
2197 -- It is improper to freeze an external entity within a generic because
2198 -- its freeze node will appear in a non-valid context. The entity will
2199 -- be frozen in the proper scope after the current generic is analyzed.
2204 -- Do not freeze a global entity within an inner scope created during
2205 -- expansion. A call to subprogram E within some internal procedure
2206 -- (a stream attribute for example) might require freezing E, but the
2207 -- freeze node must appear in the same declarative part as E itself.
2208 -- The two-pass elaboration mechanism in gigi guarantees that E will
2209 -- be frozen before the inner call is elaborated. We exclude constants
2210 -- from this test, because deferred constants may be frozen early, and
2211 -- must be diagnosed (e.g. in the case of a deferred constant being used
2212 -- in a default expression). If the enclosing subprogram comes from
2213 -- source, or is a generic instance, then the freeze point is the one
2214 -- mandated by the language, and we freeze the entity. A subprogram that
2215 -- is a child unit body that acts as a spec does not have a spec that
2216 -- comes from source, but can only come from source.
2221 then
2222 declare
2225 begin
2231 then
2233 else
2242 -- Similarly, an inlined instance body may make reference to global
2243 -- entities, but these references cannot be the proper freezing point
2244 -- for them, and in the absence of inlining freezing will take place in
2245 -- their own scope. Normally instance bodies are analyzed after the
2246 -- enclosing compilation, and everything has been frozen at the proper
2247 -- place, but with front-end inlining an instance body is compiled
2248 -- before the end of the enclosing scope, and as a result out-of-order
2249 -- freezing must be prevented.
2251 elsif Front_End_Inlining
2252 and then In_Instance_Body
2254 then
2255 declare
2258 begin
2262 else
2273 -- Here to freeze the entity
2278 -- Case of entity being frozen is other than a type
2282 -- If entity is exported or imported and does not have an external
2283 -- name, now is the time to provide the appropriate default name.
2284 -- Skip this if the entity is stubbed, since we don't need a name
2285 -- for any stubbed routine.
2290 then
2291 Set_Encoded_Interface_Name
2294 -- Special processing for atomic objects appearing in object decls
2299 then
2300 declare
2303 begin
2304 -- If expression is an aggregate, assign to a temporary to
2305 -- ensure that the actual assignment is done atomically rather
2306 -- than component-wise (the assignment to the temp may be done
2307 -- component-wise, but that is harmless).
2312 -- If the expression is a reference to a record or array object
2313 -- entity, then reset Is_True_Constant to False so that the
2314 -- compiler will not optimize away the intermediate object,
2315 -- which we need in this case for the same reason (to ensure
2316 -- that the actual assignment is atomic, rather than
2317 -- component-wise).
2321 or else
2323 then
2329 -- For a subprogram, freeze all parameter types and also the return
2330 -- type (RM 13.14(14)). However skip this for internal subprograms.
2331 -- This is also the point where any extra formal parameters are
2332 -- created since we now know whether the subprogram will use
2333 -- a foreign convention.
2337 declare
2342 begin
2343 -- Loop through formals
2355 then
2356 -- If the type of a formal is incomplete, subprogram
2357 -- is being frozen prematurely. Within an instance
2358 -- (but not within a wrapper package) this is an
2359 -- an artifact of our need to regard the end of an
2360 -- instantiation as a freeze point. Otherwise it is
2361 -- a definite error.
2363 -- and then not Is_Wrapper_Package (Current_Scope) ???
2369 elsif not After_Last_Declaration
2370 and then not Freezing_Library_Level_Tagged_Type
2371 then
2373 Error_Msg
2375 Loc);
2379 -- Check suspicious parameter for C function. These tests
2380 -- apply only to exported/imported subprograms.
2382 if Warn_On_Export_Import
2385 or else
2392 then
2395 -- Check suspicious use of fat C pointer
2399 then
2400 Error_Msg_N
2404 -- Check suspicious return of boolean
2410 then
2411 Error_Msg_N
2415 -- Check suspicious tagged type
2419 and then
2420 Is_Tagged_Type
2423 then
2424 Error_Msg_N
2428 -- Check wrong convention subprogram pointer
2432 then
2433 Error_Msg_N
2437 Error_Msg_NE
2445 -- Check for unconstrained array in exported foreign
2446 -- convention case.
2452 and then Warn_On_Export_Import
2453 then
2456 -- If this is an inherited operation, place the
2457 -- warning on the derived type declaration, rather
2458 -- than on the original subprogram.
2461 N_Full_Type_Declaration
2462 then
2466 Error_Msg_NE
2469 else
2473 Error_Msg_NE
2476 Error_Msg_NE
2482 -- Ada 2005 (AI-326): Check wrong use of tag incomplete
2483 -- types with unknown discriminants. For example:
2485 -- type T (<>) is tagged;
2486 -- procedure P (X : access T); -- ERROR
2487 -- procedure P (X : T); -- ERROR
2498 and then Unknown_Discriminants_Present
2501 then
2502 Error_Msg_N
2506 -- If the formal is an anonymous_access_to_subprogram
2507 -- freeze the subprogram type as well, to prevent
2508 -- scope anomalies in gigi, because there is no other
2509 -- clear point at which it could be frozen.
2513 then
2521 -- Case of function
2525 -- Freeze return type
2530 -- Check suspicious return type for C function
2532 if Warn_On_Export_Import
2534 or else
2537 then
2538 -- Check suspicious return of fat C pointer
2544 then
2545 Error_Msg_N
2549 -- Check suspicious return of boolean
2556 then
2557 Error_Msg_N
2561 -- Check suspicious return tagged type
2565 and then
2566 Is_Tagged_Type
2571 then
2572 Error_Msg_N
2576 -- Check return of wrong convention subprogram pointer
2582 then
2583 Error_Msg_N
2587 Error_Msg_NE
2597 and then Warn_On_Export_Import
2600 then
2601 Error_Msg_N
2605 -- Ada 2005 (AI-326): Check wrong use of tagged
2606 -- incomplete type
2608 -- type T is tagged;
2609 -- function F (X : Boolean) return T; -- ERROR
2611 -- The type must be declared in the current scope for the
2612 -- use to be legal, and the full view must be available
2613 -- when the construct that mentions it is frozen.
2619 then
2620 Error_Msg_N
2622 E);
2628 -- Must freeze its parent first if it is a derived subprogram
2634 -- We don't freeze internal subprograms, because we don't normally
2635 -- want addition of extra formals or mechanism setting to happen
2636 -- for those. However we do pass through predefined dispatching
2637 -- cases, since extra formals may be needed in some cases, such as
2638 -- for the stream 'Input function (build-in-place formals).
2642 then
2646 -- Here for other than a subprogram or type
2648 else
2649 -- For a generic package, freeze types within, so that proper
2650 -- cross-reference information is generated for tagged types.
2651 -- This is the only freeze processing needed for generic packages.
2654 declare
2657 begin
2668 -- If entity has a type, and it is not a generic unit, then
2669 -- freeze it first (RM 13.14(10)).
2673 then
2677 -- Special processing for objects created by object declaration
2681 -- For object created by object declaration, perform required
2682 -- categorization (preelaborate and pure) checks. Defer these
2683 -- checks to freeze time since pragma Import inhibits default
2684 -- initialization and thus pragma Import affects these checks.
2688 -- If there is an address clause, check that it is valid
2692 -- If the object needs any kind of default initialization, an
2693 -- error must be issued if No_Default_Initialization applies.
2694 -- The check doesn't apply to imported objects, which are not
2695 -- ever default initialized, and is why the check is deferred
2696 -- until freezing, at which point we know if Import applies.
2697 -- Deferred constants are also exempted from this test because
2698 -- their completion is explicit, or through an import pragma.
2702 then
2708 and then
2713 or else
2716 then
2717 Check_Restriction
2721 -- For imported objects, set Is_Public unless there is also an
2722 -- address clause, which means that there is no external symbol
2723 -- needed for the Import (Is_Public may still be set for other
2724 -- unrelated reasons). Note that we delayed this processing
2725 -- till freeze time so that we can be sure not to set the flag
2726 -- if there is an address clause. If there is such a clause,
2727 -- then the only purpose of the Import pragma is to suppress
2728 -- implicit initialization.
2732 then
2736 -- For convention C objects of an enumeration type, warn if
2737 -- the size is not integer size and no explicit size given.
2738 -- Skip warning for Boolean, and Character, assume programmer
2739 -- expects 8-bit sizes for these cases.
2742 or else
2749 then
2751 Error_Msg_N
2753 E);
2758 -- Check that a constant which has a pragma Volatile[_Components]
2759 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
2761 -- Note: Atomic[_Components] also sets Volatile[_Components]
2766 then
2767 -- Make sure we actually have a pragma, and have not merely
2768 -- inherited the indication from elsewhere (e.g. an address
2769 -- clause, which is not good enough in RM terms!)
2772 or else
2774 then
2775 Error_Msg_N
2780 or else
2782 then
2783 Error_Msg_N
2789 -- Static objects require special handling
2793 then
2797 -- Remaining step is to layout objects
2800 or else
2802 or else
2804 or else
2806 then
2811 -- Case of a type or subtype being frozen
2813 else
2814 -- We used to check here that a full type must have preelaborable
2815 -- initialization if it completes a private type specified with
2816 -- pragma Preelaborable_Intialization, but that missed cases where
2817 -- the types occur within a generic package, since the freezing
2818 -- that occurs within a containing scope generally skips traversal
2819 -- of a generic unit's declarations (those will be frozen within
2820 -- instances). This check was moved to Analyze_Package_Specification.
2822 -- The type may be defined in a generic unit. This can occur when
2823 -- freezing a generic function that returns the type (which is
2824 -- defined in a parent unit). It is clearly meaningless to freeze
2825 -- this type. However, if it is a subtype, its size may be determi-
2826 -- nable and used in subsequent checks, so might as well try to
2827 -- compute it.
2831 then
2836 -- Deal with special cases of freezing for subtype
2840 -- Before we do anything else, a specialized test for the case of
2841 -- a size given for an array where the array needs to be packed,
2842 -- but was not so the size cannot be honored. This would of course
2843 -- be caught by the backend, and indeed we don't catch all cases.
2844 -- The point is that we can give a better error message in those
2845 -- cases that we do catch with the circuitry here. Also if pragma
2846 -- Implicit_Packing is set, this is where the packing occurs.
2848 -- The reason we do this so early is that the processing in the
2849 -- automatic packing case affects the layout of the base type, so
2850 -- it must be done before we freeze the base type.
2853 declare
2857 begin
2858 -- Check enabling conditions. These are straightforward
2859 -- except for the test for a limited composite type. This
2860 -- eliminates the rare case of a array of limited components
2861 -- where there are issues of whether or not we can go ahead
2862 -- and pack the array (since we can't freely pack and unpack
2863 -- arrays if they are limited).
2865 -- Note that we check the root type explicitly because the
2866 -- whole point is we are doing this test before we have had
2867 -- a chance to freeze the base type (and it is that freeze
2868 -- action that causes stuff to be inherited).
2880 then
2887 then
2888 declare
2898 -- What we are looking for here is the situation where
2899 -- the RM_Size given would be exactly right if there
2900 -- was a pragma Pack (resulting in the component size
2901 -- being the same as the RM_Size). Furthermore, the
2902 -- component type size must be an odd size (not a
2903 -- multiple of storage unit)
2905 begin
2908 then
2909 -- For implicit packing mode, just set the
2910 -- component size silently
2918 -- Otherwise give an error message
2920 else
2921 Error_Msg_NE
2923 Error_Msg_N
2934 -- If ancestor subtype present, freeze that first. Note that this
2935 -- will also get the base type frozen.
2942 -- Otherwise freeze the base type of the entity before freezing
2943 -- the entity itself (RM 13.14(15)).
2949 -- For a derived type, freeze its parent type first (RM 13.14(15))
2956 -- For array type, freeze index types and component type first
2957 -- before freezing the array (RM 13.14(15)).
2960 declare
2964 -- Set true if any of the index types is an enumeration type
2965 -- with a non-standard representation.
2967 begin
2976 then
2983 -- Processing that is done only for base types
2987 -- Propagate flags for component type
2991 then
2999 -- If packing was requested or if the component size was set
3000 -- explicitly, then see if bit packing is required. This
3001 -- processing is only done for base types, since all the
3002 -- representation aspects involved are type-related. This
3003 -- is not just an optimization, if we start processing the
3004 -- subtypes, they interfere with the settings on the base
3005 -- type (this is because Is_Packed has a slightly different
3006 -- meaning before and after freezing).
3008 declare
3012 begin
3016 then
3025 else
3028 -- We can set the component size if it is less than
3029 -- 16, rounding it up to the next storage unit size.
3035 else
3039 -- Set component size up to match alignment if it
3040 -- would otherwise be less than the alignment. This
3041 -- deals with cases of types whose alignment exceeds
3042 -- their size (padded types).
3045 declare
3047 begin
3055 -- Case of component size that may result in packing
3058 declare
3064 Get_Attribute_Definition_Clause
3066 begin
3067 -- Warn if we have pack and component size so that
3068 -- the pack is ignored.
3070 -- Note: here we must check for the presence of a
3071 -- component size before checking for a Pack pragma
3072 -- to deal with the case where the array type is a
3073 -- derived type whose parent is currently private.
3077 then
3079 Error_Msg_NE
3082 Error_Msg_N
3084 Pack_Pragma);
3087 -- Set component size if not already set by a
3088 -- component size clause.
3094 -- Check for base type of 8, 16, 32 bits, where an
3095 -- unsigned subtype has a length one less than the
3096 -- base type (e.g. Natural subtype of Integer).
3098 -- In such cases, if a component size was not set
3099 -- explicitly, then generate a warning.
3103 and then
3106 then
3110 Error_Msg_N
3113 Error_Msg_N
3119 -- Actual packing is not needed for 8, 16, 32, 64.
3120 -- Also not needed for 24 if alignment is 1.
3127 then
3128 -- Here the array was requested to be packed,
3129 -- but the packing request had no effect, so
3130 -- Is_Packed is reset.
3132 -- Note: semantically this means that we lose
3133 -- track of the fact that a derived type
3134 -- inherited a pragma Pack that was non-
3135 -- effective, but that seems fine.
3137 -- We regard a Pack pragma as a request to set
3138 -- a representation characteristic, and this
3139 -- request may be ignored.
3143 -- In all other cases, packing is indeed needed
3145 else
3154 -- Processing that is done only for subtypes
3156 else
3157 -- Acquire alignment from base type
3165 -- For bit-packed arrays, check the size
3169 then
3170 declare
3176 begin
3177 -- It is not clear if it is possible to have no size
3178 -- clause at this stage, but it is not worth worrying
3179 -- about. Post error on the entity name in the size
3180 -- clause if present, else on the type entity itself.
3184 else
3190 -- If any of the index types was an enumeration type with
3191 -- a non-standard rep clause, then we indicate that the
3192 -- array type is always packed (even if it is not bit packed).
3201 -- If the array is packed, we must create the packed array
3202 -- type to be used to actually implement the type. This is
3203 -- only needed for real array types (not for string literal
3204 -- types, since they are present only for the front end).
3208 then
3212 -- Size information of packed array type is copied to the
3213 -- array type, since this is really the representation. But
3214 -- do not override explicit existing size values. If the
3215 -- ancestor subtype is constrained the packed_array_type
3216 -- will be inherited from it, but the size may have been
3217 -- provided already, and must not be overridden either.
3220 and then
3223 then
3233 -- For non-packed arrays set the alignment of the array to the
3234 -- alignment of the component type if it is unknown. Skip this
3235 -- in atomic case (atomic arrays may need larger alignments).
3244 then
3249 -- For a class-wide type, the corresponding specific type is
3250 -- frozen as well (RM 13.14(15))
3255 -- If the base type of the class-wide type is still incomplete,
3256 -- the class-wide remains unfrozen as well. This is legal when
3257 -- E is the formal of a primitive operation of some other type
3258 -- which is being frozen.
3265 -- If the Class_Wide_Type is an Itype (when type is the anonymous
3266 -- parent of a derived type) and it is a library-level entity,
3267 -- generate an itype reference for it. Otherwise, its first
3268 -- explicit reference may be in an inner scope, which will be
3269 -- rejected by the back-end.
3273 then
3274 declare
3277 begin
3281 else
3287 -- The equivalent type associated with a class-wide subtype needs
3288 -- to be frozen to ensure that its layout is done. Class-wide
3289 -- subtypes are currently only frozen on targets requiring
3290 -- front-end layout (see New_Class_Wide_Subtype and
3291 -- Make_CW_Equivalent_Type in exp_util.adb).
3295 then
3299 -- For a record (sub)type, freeze all the component types (RM
3300 -- 13.14(15). We test for E_Record_(sub)Type here, rather than using
3301 -- Is_Record_Type, because we don't want to attempt the freeze for
3302 -- the case of a private type with record extension (we will do that
3303 -- later when the full type is frozen).
3307 then
3310 -- For a concurrent type, freeze corresponding record type. This
3311 -- does not correspond to any specific rule in the RM, but the
3312 -- record type is essentially part of the concurrent type.
3313 -- Freeze as well all local entities. This includes record types
3314 -- created for entry parameter blocks, and whatever local entities
3315 -- may appear in the private part.
3319 Freeze_And_Append
3332 then
3342 -- Private types are required to point to the same freeze node as
3343 -- their corresponding full views. The freeze node itself has to
3344 -- point to the partial view of the entity (because from the partial
3345 -- view, we can retrieve the full view, but not the reverse).
3346 -- However, in order to freeze correctly, we need to freeze the full
3347 -- view. If we are freezing at the end of a scope (or within the
3348 -- scope of the private type), the partial and full views will have
3349 -- been swapped, the full view appears first in the entity chain and
3350 -- the swapping mechanism ensures that the pointers are properly set
3351 -- (on scope exit).
3353 -- If we encounter the partial view before the full view (e.g. when
3354 -- freezing from another scope), we freeze the full view, and then
3355 -- set the pointers appropriately since we cannot rely on swapping to
3356 -- fix things up (subtypes in an outer scope might not get swapped).
3360 then
3361 -- The construction of the dispatch table associated with library
3362 -- level tagged types forces freezing of all the primitives of the
3363 -- type, which may cause premature freezing of the partial view.
3364 -- For example:
3366 -- package Pkg is
3367 -- type T is tagged private;
3368 -- type DT is new T with private;
3369 -- procedure Prim (X : in out T; Y : in out DT'class);
3370 -- private
3371 -- type T is tagged null record;
3372 -- Obj : T;
3373 -- type DT is new T with null record;
3374 -- end;
3376 -- In this case the type will be frozen later by the usual
3377 -- mechanism: an object declaration, an instantiation, or the
3378 -- end of a declarative part.
3382 then
3386 -- Case of full view present
3390 -- If full view has already been frozen, then no further
3391 -- processing is required
3399 -- Otherwise freeze full view and patch the pointers so that
3400 -- the freeze node will elaborate both views in the back-end.
3402 else
3403 declare
3406 begin
3409 then
3410 Freeze_And_Append
3423 else
3424 -- {Incomplete,Private}_Subtypes with Full_Views
3425 -- constrained by discriminants.
3436 -- AI-117 requires that the convention of a partial view be the
3437 -- same as the convention of the full view. Note that this is a
3438 -- recognized breach of privacy, but it's essential for logical
3439 -- consistency of representation, and the lack of a rule in
3440 -- RM95 was an oversight.
3447 -- Size information is copied from the full view to the
3448 -- incomplete or private view for consistency.
3450 -- We skip this is the full view is not a type. This is very
3451 -- strange of course, and can only happen as a result of
3452 -- certain illegalities, such as a premature attempt to derive
3453 -- from an incomplete type.
3462 -- Case of no full view present. If entity is derived or subtype,
3463 -- it is safe to freeze, correctness depends on the frozen status
3464 -- of parent. Otherwise it is either premature usage, or a Taft
3465 -- amendment type, so diagnosis is at the point of use and the
3466 -- type might be frozen later.
3470 then
3473 else
3478 -- For access subprogram, freeze types of all formals, the return
3479 -- type was already frozen, since it is the Etype of the function.
3490 -- Ada 2005 (AI-326): Check wrong use of tag incomplete type
3492 -- type T is tagged;
3493 -- type Acc is access function (X : T) return T; -- ERROR
3499 then
3500 Error_Msg_N
3504 -- For access to a protected subprogram, freeze the equivalent type
3505 -- (however this is not set if we are not generating code or if this
3506 -- is an anonymous type used just for resolution).
3510 -- AI-326: Check wrong use of tagged incomplete types
3512 -- type T is tagged;
3513 -- type As3D is access protected
3514 -- function (X : Float) return T; -- ERROR
3516 declare
3519 begin
3530 then
3531 Error_Msg_N
3541 -- Generic types are never seen by the back-end, and are also not
3542 -- processed by the expander (since the expander is turned off for
3543 -- generic processing), so we never need freeze nodes for them.
3549 -- Some special processing for non-generic types to complete
3550 -- representation details not known till the freeze point.
3555 -- Some error checks required for ordinary fixed-point type. Defer
3556 -- these till the freeze-point since we need the small and range
3557 -- values. We only do these checks for base types
3561 then
3564 Error_Msg_N
3569 Error_Msg_N
3575 Error_Msg_N
3581 Error_Msg_N
3594 -- Check restriction for standard storage pool
3600 -- Deal with error message for pure access type. This is not an
3601 -- error in Ada 2005 if there is no pool (see AI-366).
3606 then
3610 Error_Msg_N
3614 Error_Msg_N
3617 else
3618 Error_Msg_N
3625 -- Case of composite types
3629 -- AI-117 requires that all new primitives of a tagged type must
3630 -- inherit the convention of the full view of the type. Inherited
3631 -- and overriding operations are defined to inherit the convention
3632 -- of their parent or overridden subprogram (also specified in
3633 -- AI-117), which will have occurred earlier (in Derive_Subprogram
3634 -- and New_Overloaded_Entity). Here we set the convention of
3635 -- primitives that are still convention Ada, which will ensure
3636 -- that any new primitives inherit the type's convention. Class-
3637 -- wide types can have a foreign convention inherited from their
3638 -- specific type, but are excluded from this since they don't have
3639 -- any associated primitives.
3644 then
3645 declare
3648 begin
3661 -- Generate references to primitive operations for a tagged type
3665 -- Now that all types from which E may depend are frozen, see if the
3666 -- size is known at compile time, if it must be unsigned, or if
3667 -- strict alignment is required
3676 -- Do not allow a size clause for a type which does not have a size
3677 -- that is known at compile time
3681 then
3682 -- Suppress this message if errors posted on E, even if we are
3683 -- in all errors mode, since this is often a junk message
3686 Error_Msg_N
3692 -- Remaining process is to set/verify the representation information,
3693 -- in particular the size and alignment values. This processing is
3694 -- not required for generic types, since generic types do not play
3695 -- any part in code generation, and so the size and alignment values
3696 -- for such types are irrelevant.
3701 -- Otherwise we call the layout procedure
3703 else
3707 -- End of freeze processing for type entities
3710 -- Here is where we logically freeze the current entity. If it has a
3711 -- freeze node, then this is the point at which the freeze node is
3712 -- linked into the result list.
3716 -- If a freeze node is already allocated, use it, otherwise allocate
3717 -- a new one. The preallocation happens in the case of anonymous base
3718 -- types, where we preallocate so that we can set First_Subtype_Link.
3719 -- Note that we reset the Sloc to the current freeze location.
3725 else
3737 else
3741 -- A final pass over record types with discriminants. If the type
3742 -- has an incomplete declaration, there may be constrained access
3743 -- subtypes declared elsewhere, which do not depend on the discrimi-
3744 -- nants of the type, and which are used as component types (i.e.
3745 -- the full view is a recursive type). The designated types of these
3746 -- subtypes can only be elaborated after the type itself, and they
3747 -- need an itype reference.
3751 then
3752 declare
3757 begin
3768 then
3780 -- When a type is frozen, the first subtype of the type is frozen as
3781 -- well (RM 13.14(15)). This has to be done after freezing the type,
3782 -- since obviously the first subtype depends on its own base type.
3787 -- If we just froze a tagged non-class wide record, then freeze the
3788 -- corresponding class-wide type. This must be done after the tagged
3789 -- type itself is frozen, because the class-wide type refers to the
3790 -- tagged type which generates the class.
3795 then
3802 -- Special handling for subprograms
3806 -- If subprogram has address clause then reset Is_Public flag, since
3807 -- we do not want the backend to generate external references.
3811 then
3814 -- If no address clause and not intrinsic, then for imported
3815 -- subprogram in main unit, generate descriptor if we are in
3816 -- Propagate_Exceptions mode.
3818 elsif Propagate_Exceptions
3822 then
3832 -----------------------------
3833 -- Freeze_Enumeration_Type --
3834 -----------------------------
3837 begin
3838 -- By default, if no size clause is present, an enumeration type with
3839 -- Convention C is assumed to interface to a C enum, and has integer
3840 -- size. This applies to types. For subtypes, verify that its base
3841 -- type has no size clause either.
3847 then
3850 else
3851 -- If the enumeration type interfaces to C, and it has a size clause
3852 -- that specifies less than int size, it warrants a warning. The
3853 -- user may intend the C type to be an enum or a char, so this is
3854 -- not by itself an error that the Ada compiler can detect, but it
3855 -- it is a worth a heads-up. For Boolean and Character types we
3856 -- assume that the programmer has the proper C type in mind.
3863 then
3864 Error_Msg_N
3872 -----------------------
3873 -- Freeze_Expression --
3874 -----------------------
3885 -- This flag is set true if the entity must be frozen outside the
3886 -- current subprogram. This happens in the case of expander generated
3887 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
3888 -- not freeze all entities like other bodies, but which nevertheless
3889 -- may reference entities that have to be frozen before the body and
3890 -- obviously cannot be frozen inside the body.
3893 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
3894 -- it is the handled statement sequence of an expander-generated
3895 -- subprogram (init proc, stream subprogram, or renaming as body).
3896 -- If so, this is not a freezing context.
3898 -----------------
3899 -- In_Exp_Body --
3900 -----------------
3906 begin
3909 else
3916 else
3926 N_Subprogram_Renaming_Declaration)
3927 then
3929 else
3935 -- Start of processing for Freeze_Expression
3937 begin
3938 -- Immediate return if freezing is inhibited. This flag is set by the
3939 -- analyzer to stop freezing on generated expressions that would cause
3940 -- freezing if they were in the source program, but which are not
3941 -- supposed to freeze, since they are created.
3947 -- If expression is non-static, then it does not freeze in a default
3948 -- expression, see section "Handling of Default Expressions" in the
3949 -- spec of package Sem for further details. Note that we have to
3950 -- make sure that we actually have a real expression (if we have
3951 -- a subtype indication, we can't test Is_Static_Expression!)
3953 if In_Spec_Exp
3956 then
3960 -- Freeze type of expression if not frozen already
3968 -- Base type may be an derived numeric type that is frozen at
3969 -- the point of declaration, but first_subtype is still unfrozen.
3976 -- For entity name, freeze entity if not frozen already. A special
3977 -- exception occurs for an identifier that did not come from source.
3978 -- We don't let such identifiers freeze a non-internal entity, i.e.
3979 -- an entity that did come from source, since such an identifier was
3980 -- generated by the expander, and cannot have any semantic effect on
3981 -- the freezing semantics. For example, this stops the parameter of
3982 -- an initialization procedure from freezing the variable.
3989 then
3991 else
3995 -- For an allocator freeze designated type if not frozen already
3997 -- For an aggregate whose component type is an access type, freeze the
3998 -- designated type now, so that its freeze does not appear within the
3999 -- loop that might be created in the expansion of the aggregate. If the
4000 -- designated type is a private type without full view, the expression
4001 -- cannot contain an allocator, so the type is not frozen.
4012 then
4016 when N_Selected_Component |
4017 N_Indexed_Component |
4018 N_Slice =>
4031 then
4035 -- All done if nothing needs freezing
4040 then
4044 -- Loop for looking at the right place to insert the freeze nodes
4045 -- exiting from the loop when it is appropriate to insert the freeze
4046 -- node before the current node P.
4048 -- Also checks some special exceptions to the freezing rules. These
4049 -- cases result in a direct return, bypassing the freeze action.
4052 loop
4055 -- If we don't have a parent, then we are not in a well-formed tree.
4056 -- This is an unusual case, but there are some legitimate situations
4057 -- in which this occurs, notably when the expressions in the range of
4058 -- a type declaration are resolved. We simply ignore the freeze
4059 -- request in this case. Is this right ???
4065 -- See if we have got to an appropriate point in the tree
4069 -- A special test for the exception of (RM 13.14(8)) for the case
4070 -- of per-object expressions (RM 3.8(18)) occurring in component
4071 -- definition or a discrete subtype definition. Note that we test
4072 -- for a component declaration which includes both cases we are
4073 -- interested in, and furthermore the tree does not have explicit
4074 -- nodes for either of these two constructs.
4078 -- The case we want to test for here is an identifier that is
4079 -- a per-object expression, this is either a discriminant that
4080 -- appears in a context other than the component declaration
4081 -- or it is a reference to the type of the enclosing construct.
4083 -- For either of these cases, we skip the freezing
4085 if not In_Spec_Expression
4088 then
4089 -- We recognize the discriminant case by just looking for
4090 -- a reference to a discriminant. It can only be one for
4091 -- the enclosing construct. Skip freezing in this case.
4096 -- For the case of a reference to the enclosing record,
4097 -- (or task or protected type), we look for a type that
4098 -- matches the current scope.
4105 -- If we have an enumeration literal that appears as the choice in
4106 -- the aggregate of an enumeration representation clause, then
4107 -- freezing does not occur (RM 13.14(10)).
4111 -- The case we are looking for is an enumeration literal
4115 then
4116 -- If enumeration literal appears directly as the choice,
4117 -- do not freeze (this is the normal non-overloaded case)
4121 then
4124 -- If enumeration literal appears as the name of function
4125 -- which is the choice, then also do not freeze. This
4126 -- happens in the overloaded literal case, where the
4127 -- enumeration literal is temporarily changed to a function
4128 -- call for overloading analysis purposes.
4131 and then
4133 and then
4135 then
4140 -- Normally if the parent is a handled sequence of statements,
4141 -- then the current node must be a statement, and that is an
4142 -- appropriate place to insert a freeze node.
4146 -- An exception occurs when the sequence of statements is for
4147 -- an expander generated body that did not do the usual freeze
4148 -- all operation. In this case we usually want to freeze
4149 -- outside this body, not inside it, and we skip past the
4150 -- subprogram body that we are inside.
4154 -- However, we *do* want to freeze at this point if we have
4155 -- an entity to freeze, and that entity is declared *inside*
4156 -- the body of the expander generated procedure. This case
4157 -- is recognized by the scope of the type, which is either
4158 -- the spec for some enclosing body, or (in the case of
4159 -- init_procs, for which there are no separate specs) the
4160 -- current scope.
4162 declare
4166 begin
4171 or else
4173 then
4179 then
4185 -- If not that exception to the exception, then this is
4186 -- where we delay the freeze till outside the body.
4191 -- Here if normal case where we are in handled statement
4192 -- sequence and want to do the insertion right there.
4194 else
4198 -- If parent is a body or a spec or a block, then the current node
4199 -- is a statement or declaration and we can insert the freeze node
4200 -- before it.
4202 when N_Package_Specification |
4203 N_Package_Body |
4204 N_Subprogram_Body |
4205 N_Task_Body |
4206 N_Protected_Body |
4207 N_Entry_Body |
4210 -- The expander is allowed to define types in any statements list,
4211 -- so any of the following parent nodes also mark a freezing point
4212 -- if the actual node is in a list of statements or declarations.
4214 when N_Exception_Handler |
4215 N_If_Statement |
4216 N_Elsif_Part |
4217 N_Case_Statement_Alternative |
4218 N_Compilation_Unit_Aux |
4219 N_Selective_Accept |
4220 N_Accept_Alternative |
4221 N_Delay_Alternative |
4222 N_Conditional_Entry_Call |
4223 N_Entry_Call_Alternative |
4224 N_Triggering_Alternative |
4225 N_Abortable_Part |
4226 N_Freeze_Entity =>
4230 -- Note: The N_Loop_Statement is a special case. A type that
4231 -- appears in the source can never be frozen in a loop (this
4232 -- occurs only because of a loop expanded by the expander), so we
4233 -- keep on going. Otherwise we terminate the search. Same is true
4234 -- of any entity which comes from source. (if they have predefined
4235 -- type, that type does not appear to come from source, but the
4236 -- entity should not be frozen here).
4242 -- For all other cases, keep looking at parents
4248 -- We fall through the case if we did not yet find the proper
4249 -- place in the free for inserting the freeze node, so climb!
4254 -- If the expression appears in a record or an initialization procedure,
4255 -- the freeze nodes are collected and attached to the current scope, to
4256 -- be inserted and analyzed on exit from the scope, to insure that
4257 -- generated entities appear in the correct scope. If the expression is
4258 -- a default for a discriminant specification, the scope is still void.
4259 -- The expression can also appear in the discriminant part of a private
4260 -- or concurrent type.
4262 -- If the expression appears in a constrained subcomponent of an
4263 -- enclosing record declaration, the freeze nodes must be attached to
4264 -- the outer record type so they can eventually be placed in the
4265 -- enclosing declaration list.
4267 -- The other case requiring this special handling is if we are in a
4268 -- default expression, since in that case we are about to freeze a
4269 -- static type, and the freeze scope needs to be the outer scope, not
4270 -- the scope of the subprogram with the default parameter.
4272 -- For default expressions and other spec expressions in generic units,
4273 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
4274 -- placing them at the proper place, after the generic unit.
4277 or else Freeze_Outside
4282 then
4283 declare
4288 begin
4301 -- The current scope may be that of a constrained component of
4302 -- an enclosing record declaration, which is above the current
4303 -- scope in the scope stack.
4312 Freeze_Nodes;
4313 else
4323 -- Now we have the right place to do the freezing. First, a special
4324 -- adjustment, if we are in spec-expression analysis mode, these freeze
4325 -- actions must not be thrown away (normally all inserted actions are
4326 -- thrown away in this mode. However, the freeze actions are from static
4327 -- expressions and one of the important reasons we are doing this
4328 -- special analysis is to get these freeze actions. Therefore we turn
4329 -- off the In_Spec_Expression mode to propagate these freeze actions.
4330 -- This also means they get properly analyzed and expanded.
4334 -- Freeze the designated type of an allocator (RM 13.14(13))
4340 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
4341 -- the enumeration representation clause exception in the loop above.
4347 -- Freeze name if one is present (RM 13.14(11))
4353 -- Restore In_Spec_Expression flag
4358 -----------------------------
4359 -- Freeze_Fixed_Point_Type --
4360 -----------------------------
4362 -- Certain fixed-point types and subtypes, including implicit base types
4363 -- and declared first subtypes, have not yet set up a range. This is
4364 -- because the range cannot be set until the Small and Size values are
4365 -- known, and these are not known till the type is frozen.
4367 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
4368 -- whose bounds are unanalyzed real literals. This routine will recognize
4369 -- this case, and transform this range node into a properly typed range
4370 -- with properly analyzed and resolved values.
4388 -- Returns size of type with given bounds. Also leaves these
4389 -- bounds set as the current bounds of the Typ.
4391 -----------
4392 -- Fsize --
4393 -----------
4396 begin
4402 -- Start of processing for Freeze_Fixed_Point_Type
4404 begin
4405 -- If Esize of a subtype has not previously been set, set it now
4412 else
4417 -- Immediate return if the range is already analyzed. This means that
4418 -- the range is already set, and does not need to be computed by this
4419 -- routine.
4425 -- Immediate return if either of the bounds raises Constraint_Error
4429 then
4436 -- Ordinary fixed-point case
4440 -- For the ordinary fixed-point case, we are allowed to fudge the
4441 -- end-points up or down by small. Generally we prefer to fudge up,
4442 -- i.e. widen the bounds for non-model numbers so that the end points
4443 -- are included. However there are cases in which this cannot be
4444 -- done, and indeed cases in which we may need to narrow the bounds.
4445 -- The following circuit makes the decision.
4447 -- Note: our terminology here is that Incl_EP means that the bounds
4448 -- are widened by Small if necessary to include the end points, and
4449 -- Excl_EP means that the bounds are narrowed by Small to exclude the
4450 -- end-points if this reduces the size.
4452 -- Note that in the Incl case, all we care about is including the
4453 -- end-points. In the Excl case, we want to narrow the bounds as
4454 -- much as permitted by the RM, to give the smallest possible size.
4471 begin
4472 -- First step. Base types are required to be symmetrical. Right
4473 -- now, the base type range is a copy of the first subtype range.
4474 -- This will be corrected before we are done, but right away we
4475 -- need to deal with the case where both bounds are non-negative.
4476 -- In this case, we set the low bound to the negative of the high
4477 -- bound, to make sure that the size is computed to include the
4478 -- required sign. Note that we do not need to worry about the
4479 -- case of both bounds negative, because the sign will be dealt
4480 -- with anyway. Furthermore we can't just go making such a bound
4481 -- symmetrical, since in a twos-complement system, there is an
4482 -- extra negative value which could not be accommodated on the
4483 -- positive side.
4488 then
4493 -- Compute the fudged bounds. If the number is a model number,
4494 -- then we do nothing to include it, but we are allowed to backoff
4495 -- to the next adjacent model number when we exclude it. If it is
4496 -- not a model number then we straddle the two values with the
4497 -- model numbers on either side.
4503 else
4507 -- The low value excluding the end point is Small greater, but
4508 -- we do not do this exclusion if the low value is positive,
4509 -- since it can't help the size and could actually hurt by
4510 -- crossing the high bound.
4515 -- If the value went from negative to zero, then we have the
4516 -- case where Loval_Incl_EP is the model number just below
4517 -- zero, so we want to stick to the negative value for the
4518 -- base type to maintain the condition that the size will
4519 -- include signed values.
4523 then
4527 else
4531 -- Similar processing for upper bound and high value
4537 else
4543 else
4547 -- One further adjustment is needed. In the case of subtypes, we
4548 -- cannot go outside the range of the base type, or we get
4549 -- peculiarities, and the base type range is already set. This
4550 -- only applies to the Incl values, since clearly the Excl values
4551 -- are already as restricted as they are allowed to be.
4558 -- Get size including and excluding end points
4563 -- No need to exclude end-points if it does not reduce size
4573 -- Now we set the actual size to be used. We want to use the
4574 -- bounds fudged up to include the end-points but only if this
4575 -- can be done without violating a specifically given size
4576 -- size clause or causing an unacceptable increase in size.
4578 -- Case of size clause given
4582 -- Use the inclusive size only if it is consistent with
4583 -- the explicitly specified size.
4590 -- If the inclusive size is too large, we try excluding
4591 -- the end-points (will be caught later if does not work).
4593 else
4599 -- Case of size clause not given
4601 else
4602 -- If we have a base type whose corresponding first subtype
4603 -- has an explicit size that is large enough to include our
4604 -- end-points, then do so. There is no point in working hard
4605 -- to get a base type whose size is smaller than the specified
4606 -- size of the first subtype.
4612 then
4617 -- If excluding the end-points makes the size smaller and
4618 -- results in a size of 8,16,32,64, then we take the smaller
4619 -- size. For the 64 case, this is compulsory. For the other
4620 -- cases, it seems reasonable. We like to include end points
4621 -- if we can, but not at the expense of moving to the next
4622 -- natural boundary of size.
4625 and then
4630 then
4635 -- Otherwise we can definitely include the end points
4637 else
4643 -- One pathological case: normally we never fudge a low bound
4644 -- down, since it would seem to increase the size (if it has
4645 -- any effect), but for ranges containing single value, or no
4646 -- values, the high bound can be small too large. Consider:
4648 -- type t is delta 2.0**(-14)
4649 -- range 131072.0 .. 0;
4651 -- That lower bound is *just* outside the range of 32 bits, and
4652 -- does need fudging down in this case. Note that the bounds
4653 -- will always have crossed here, since the high bound will be
4654 -- fudged down if necessary, as in the case of:
4656 -- type t is delta 2.0**(-14)
4657 -- range 131072.0 .. 131072.0;
4659 -- So we detect the situation by looking for crossed bounds,
4660 -- and if the bounds are crossed, and the low bound is greater
4661 -- than zero, we will always back it off by small, since this
4662 -- is completely harmless.
4669 -- And of course, we need to do exactly the same parallel
4670 -- fudge for flat ranges in the negative region.
4683 -- For the decimal case, none of this fudging is required, since there
4684 -- are no end-point problems in the decimal case (the end-points are
4685 -- always included).
4687 else
4691 -- At this stage, the actual size has been calculated and the proper
4692 -- required bounds are stored in the low and high bounds.
4696 Error_Msg_N
4698 Typ);
4702 -- Check size against explicit given size
4708 Error_Msg_NE
4712 else
4716 -- Increase size to next natural boundary if no size clause given
4718 else
4725 else
4733 -- If we have a base type, then expand the bounds so that they extend to
4734 -- the full width of the allocated size in bits, to avoid junk range
4735 -- checks on intermediate computations.
4742 -- Final step is to reanalyze the bounds using the proper type
4743 -- and set the Corresponding_Integer_Value fields of the literals.
4749 -- Resolve with universal fixed if the base type, and the base type if
4750 -- it is a subtype. Note we can't resolve the base type with itself,
4751 -- that would be a reference before definition.
4755 else
4759 -- Set corresponding integer value for bound
4761 Set_Corresponding_Integer_Value
4764 -- Similar processing for high bound
4772 else
4776 Set_Corresponding_Integer_Value
4779 -- Set type of range to correspond to bounds
4783 -- Set Esize to calculated size if not set already
4789 -- Set RM_Size if not already set. If already set, check value
4791 declare
4794 begin
4799 Error_Msg_NE
4804 else
4810 ------------------
4811 -- Freeze_Itype --
4812 ------------------
4817 begin
4826 --------------------------
4827 -- Freeze_Static_Object --
4828 --------------------------
4833 -- Exception raised if the type of a static object cannot be made
4834 -- static. This happens if the type depends on non-global objects.
4837 -- Called to ensure that an expression used as part of a type definition
4838 -- is statically allocatable, which means that the expression type is
4839 -- statically allocatable, and the expression is either static, or a
4840 -- reference to a library level constant.
4843 -- Called to mark a type as static, checking that it is possible
4844 -- to set the type as static. If it is not possible, then the
4845 -- exception Cannot_Be_Static is raised.
4847 -----------------------------
4848 -- Ensure_Expression_Is_SA --
4849 -----------------------------
4854 begin
4866 then
4874 -----------------------
4875 -- Ensure_Type_Is_SA --
4876 -----------------------
4882 begin
4883 -- If type is library level, we are all set
4889 -- We are also OK if the type already marked as statically allocated,
4890 -- which means we processed it before.
4896 -- Mark type as statically allocated
4900 -- Check that it is safe to statically allocate this type
4918 declare
4922 begin
4935 else
4944 then
4963 else
4968 -- Start of processing for Freeze_Static_Object
4970 begin
4973 exception
4976 -- If the object that cannot be static is imported or exported,
4977 -- then we give an error message saying that this object cannot
4978 -- be imported or exported.
4981 Error_Msg_N
4984 -- Otherwise must be exported, something is wrong if compiler
4985 -- is marking something as statically allocated which cannot be).
4988 Error_Msg_N
4993 -----------------------
4994 -- Freeze_Subprogram --
4995 -----------------------
5001 begin
5002 -- Subprogram may not have an address clause unless it is imported
5006 Error_Msg_N
5013 -- Reset the Pure indication on an imported subprogram unless an
5014 -- explicit Pure_Function pragma was present. We do this because
5015 -- otherwise it is an insidious error to call a non-pure function from
5016 -- pure unit and have calls mysteriously optimized away. What happens
5017 -- here is that the Import can bypass the normal check to ensure that
5018 -- pure units call only pure subprograms.
5023 then
5027 -- For non-foreign convention subprograms, this is where we create
5028 -- the extra formals (for accessibility level and constrained bit
5029 -- information). We delay this till the freeze point precisely so
5030 -- that we know the convention!
5036 -- If this is convention Ada and a Valued_Procedure, that's odd
5041 and then Warn_On_Export_Import
5042 then
5043 Error_Msg_N
5048 -- Case of foreign convention
5050 else
5053 -- For foreign conventions, warn about return of an
5054 -- unconstrained array.
5056 -- Note: we *do* allow a return by descriptor for the VMS case,
5057 -- though here there is probably more to be done ???
5062 -- If no return type, probably some other error, e.g. a
5063 -- missing full declaration, so ignore.
5068 -- If the return type is generic, we have emitted a warning
5069 -- earlier on, and there is nothing else to check here. Specific
5070 -- instantiations may lead to erroneous behavior.
5078 and then Warn_On_Export_Import
5079 then
5080 Error_Msg_N
5087 -- If any of the formals for an exported foreign convention
5088 -- subprogram have defaults, then emit an appropriate warning since
5089 -- this is odd (default cannot be used from non-Ada code)
5094 if Warn_On_Export_Import
5096 then
5097 Error_Msg_N
5107 -- For VMS, descriptor mechanisms for parameters are allowed only
5108 -- for imported/exported subprograms. Moreover, the NCA descriptor
5109 -- is not allowed for parameters of exported subprograms.
5116 Error_Msg_N
5118 Error_Msg_N
5129 Error_Msg_N
5131 Error_Msg_N
5140 -- Pragma Inline_Always is disallowed for dispatching subprograms
5141 -- because the address of such subprograms is saved in the dispatch
5142 -- table to support dispatching calls, and dispatching calls cannot
5143 -- be inlined. This is consistent with the restriction against using
5144 -- 'Access or 'Address on an Inline_Always subprogram.
5148 then
5149 Error_Msg_N
5153 -- Because of the implicit representation of inherited predefined
5154 -- operators in the front-end, the overriding status of the operation
5155 -- may be affected when a full view of a type is analyzed, and this is
5156 -- not captured by the analysis of the corresponding type declaration.
5157 -- Therefore the correctness of a not-overriding indicator must be
5158 -- rechecked when the subprogram is frozen.
5162 then
5167 ----------------------
5168 -- Is_Fully_Defined --
5169 ----------------------
5172 begin
5181 then
5182 -- Verify that the record type has no components with private types
5183 -- without completion.
5185 declare
5188 begin
5201 else
5207 ---------------------------------
5208 -- Generate_Prim_Op_References --
5209 ---------------------------------
5217 begin
5218 -- Handle subtypes of synchronized types
5222 then
5224 else
5228 -- References to primitive operations are only relevant for tagged types
5232 then
5236 -- Ada 2005 (AI-345): For synchronized types generate reference
5237 -- to the wrapper that allow us to dispatch calls through their
5238 -- implemented abstract interface types.
5240 -- The check for Present here is to protect against previously
5241 -- reported critical errors.
5245 then
5246 Prim_List := Primitive_Operations
5248 else
5259 -- If the operation is derived, get the original for cross-reference
5260 -- reference purposes (it is the original for which we want the xref
5261 -- and for which the comes_from_source test must be performed).
5273 ---------------------------------
5274 -- Process_Default_Expressions --
5275 ---------------------------------
5277 procedure Process_Default_Expressions
5280 is
5287 begin
5290 -- A subprogram instance and its associated anonymous subprogram share
5291 -- their signature. The default expression functions are defined in the
5292 -- wrapper packages for the anonymous subprogram, and should not be
5293 -- generated again for the instance.
5298 then
5306 -- We work with a copy of the default expression because we
5307 -- do not want to disturb the original, since this would mess
5308 -- up the conformance checking.
5312 -- The analysis of the expression may generate insert actions,
5313 -- which of course must not be executed. We wrap those actions
5314 -- in a procedure that is not called, and later on eliminated.
5315 -- The following cases have no side-effects, and are analyzed
5316 -- directly.
5327 and then
5329 then
5331 -- If there is no default function, we must still do a full
5332 -- analyze call on the default value, to ensure that all error
5333 -- checks are performed, e.g. those associated with static
5334 -- evaluation. Note: this branch will always be taken if the
5335 -- analyzer is turned off (but we still need the error checks).
5337 -- Note: the setting of parent here is to meet the requirement
5338 -- that we can only analyze the expression while attached to
5339 -- the tree. Really the requirement is that the parent chain
5340 -- be set, we don't actually need to be in the tree.
5345 -- Default expressions are resolved with their own type if the
5346 -- context is generic, to avoid anomalies with private types.
5350 else
5354 -- If that resolved expression will raise constraint error,
5355 -- then flag the default value as raising constraint error.
5356 -- This allows a proper error message on the calls.
5362 -- If the default is a parameterless call, we use the name of
5363 -- the called function directly, and there is no body to build.
5367 then
5370 -- Else construct and analyze the body of a wrapper procedure
5371 -- that contains an object declaration to hold the expression.
5372 -- Given that this is done only to complete the analysis, it
5373 -- simpler to build a procedure than a function which might
5374 -- involve secondary stack expansion.
5376 else
5377 Dnam :=
5380 Dbody :=
5382 Specification =>
5388 Defining_Identifier =>
5391 Object_Definition =>
5395 Handled_Statement_Sequence =>
5412 ----------------------------------------
5413 -- Set_Component_Alignment_If_Not_Set --
5414 ----------------------------------------
5417 begin
5418 -- Ignore if not base type, subtypes don't need anything
5424 -- Do not override existing representation
5435 else
5436 Set_Component_Alignment
5442 ------------------
5443 -- Undelay_Type --
5444 ------------------
5447 begin
5451 -- Since we don't want T to have a Freeze_Node, we don't want its
5452 -- Full_View or Corresponding_Record_Type to have one either.
5454 -- ??? Fundamentally, this whole handling is a kludge. What we really
5455 -- want is to be sure that for an Itype that's part of record R and is a
5456 -- subtype of type T, that it's frozen after the later of the freeze
5457 -- points of R and T. We have no way of doing that directly, so what we
5458 -- do is force most such Itypes to be frozen as part of freezing R via
5459 -- this procedure and only delay the ones that need to be delayed
5460 -- (mostly the designated types of access types that are defined as part
5461 -- of the record).
5467 then
5475 then
5480 ------------------
5481 -- Warn_Overlay --
5482 ------------------
5484 procedure Warn_Overlay
5488 is
5490 -- The object to which the address clause applies
5496 begin
5497 -- No warning if address clause overlay warnings are off
5503 -- No warning if there is an explicit initialization
5511 -- We only give the warning for non-imported entities of a type for
5512 -- which a non-null base init proc is defined (or for access types which
5513 -- have implicit null initialization).
5519 then
5522 then
5527 then
5534 then
5541 -- A function call (most likely to To_Address) is probably not an
5542 -- overlay, so skip warning. Ditto if the function call was inlined
5543 -- and transformed into an entity.
5551 -- If a pragma Import follows, we assume that it is for the current
5552 -- target of the address clause, and skip the warning.
5557 then
5563 Error_Msg_N
5565 Nam);
5566 else
5567 Error_Msg_N
5569 Nam);
5572 -- Add friendly warning if initialization comes from a packed array
5573 -- component.
5576 declare
5579 begin
5585 then
5589 then
5590 Error_Msg_NE
5595 else
5602 Error_Msg_N
5605 Nam);