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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.
137 procedure Process_Default_Expressions
140 -- This procedure is called for each subprogram to complete processing
141 -- of default expressions at the point where all types are known to be
142 -- frozen. The expressions must be analyzed in full, to make sure that
143 -- all error processing is done (they have only been pre-analyzed). If
144 -- the expression is not an entity or literal, its analysis may generate
145 -- code which must not be executed. In that case we build a function
146 -- body to hold that code. This wrapper function serves no other purpose
147 -- (it used to be called to evaluate the default, but now the default is
148 -- inlined at each point of call).
151 -- Typ is a record or array type that is being frozen. This routine
152 -- sets the default component alignment from the scope stack values
153 -- if the alignment is otherwise not specified.
156 -- As each entity is frozen, this routine is called to deal with the
157 -- setting of Debug_Info_Needed for the entity. This flag is set if
158 -- the entity comes from source, or if we are in Debug_Generated_Code
159 -- mode or if the -gnatdV debug flag is set. However, it never sets
160 -- the flag if Debug_Info_Off is set. This procedure also ensures that
161 -- subsidiary entities have the flag set as required.
164 -- T is a type of a component that we know to be an Itype.
165 -- We don't want this to have a Freeze_Node, so ensure it doesn't.
166 -- Do the same for any Full_View or Corresponding_Record_Type.
168 procedure Warn_Overlay
172 -- Expr is the expression for an address clause for entity Nam whose type
173 -- is Typ. If Typ has a default initialization, and there is no explicit
174 -- initialization in the source declaration, check whether the address
175 -- clause might cause overlaying of an entity, and emit a warning on the
176 -- side effect that the initialization will cause.
178 -------------------------------
179 -- Adjust_Esize_For_Alignment --
180 -------------------------------
185 begin
191 then
197 ------------------------------------
198 -- Build_And_Analyze_Renamed_Body --
199 ------------------------------------
201 procedure Build_And_Analyze_Renamed_Body
205 is
207 begin
214 ------------------------
215 -- Build_Renamed_Body --
216 ------------------------
218 function Build_Renamed_Body
221 is
223 -- We use for the source location of the renamed body, the location
224 -- of the spec entity. It might seem more natural to use the location
225 -- of the renaming declaration itself, but that would be wrong, since
226 -- then the body we create would look as though it was created far
227 -- too late, and this could cause problems with elaboration order
228 -- analysis, particularly in connection with instantiations.
243 -- If the renamed entity is a primitive operation given in prefix form,
244 -- the prefix is the target object and it has to be added as the first
245 -- actual in the generated call.
247 begin
248 -- Determine the entity being renamed, which is the target of the call
249 -- statement. If the name is an explicit dereference, this is a renaming
250 -- of a subprogram type rather than a subprogram. The name itself is
251 -- fully analyzed.
262 else
269 else
275 -- If the renamed entity is a predefined operator, retain full name
276 -- to ensure its visibility.
280 then
282 else
286 else
289 and then
292 then
294 -- Retrieve the target object, to be added as a first actual
295 -- in the call.
300 else
304 -- The original name may have been overloaded, but
305 -- is fully resolved now.
310 -- For simple renamings, subsequent calls can be expanded directly as
311 -- called to the renamed entity. The body must be generated in any case
312 -- for calls they may appear elsewhere.
317 then
321 -- The body generated for this renaming is an internal artifact, and
322 -- does not constitute a freeze point for the called entity.
329 declare
333 begin
335 -- The controlling formal may be an access parameter, or the
336 -- actual may be an access value, so adjust accordingly.
340 then
341 Actuals := New_List
346 then
347 Actuals := New_List
351 else
359 else
370 -- If the renamed entity is an entry, inherit its profile. For other
371 -- renamings as bodies, both profiles must be subtype conformant, so it
372 -- is not necessary to replace the profile given in the declaration.
373 -- However, default values that are aggregates are rewritten when
374 -- partially analyzed, so we recover the original aggregate to insure
375 -- that subsequent conformity checking works. Similarly, if the default
376 -- expression was constant-folded, recover the original expression.
388 N_Access_Definition
389 then
397 then
408 -- If the renamed entity is a function, the generated body contains a
409 -- return statement. Otherwise, build a procedure call. If the entity is
410 -- an entry, subsequent analysis of the call will transform it into the
411 -- proper entry or protected operation call. If the renamed entity is
412 -- a character literal, return it directly.
418 then
419 Call_Node :=
421 Expression =>
427 Call_Node :=
432 Call_Node :=
436 else
437 Call_Node :=
443 -- Create entities for subprogram body and formals
457 Body_Node :=
461 Handled_Statement_Sequence =>
471 -- Link the body to the entity whose declaration it completes. If
472 -- the body is analyzed when the renamed entity is frozen, it may
473 -- be necessary to restore the proper scope (see package Exp_Ch13).
477 then
479 else
486 --------------------------
487 -- Check_Address_Clause --
488 --------------------------
496 begin
500 -- If we have no initialization of any kind, then we don't need to
501 -- place any restrictions on the address clause, because the object
502 -- will be elaborated after the address clause is evaluated. This
503 -- happens if the declaration has no initial expression, or the type
504 -- has no implicit initialization, or the object is imported.
506 -- The same holds for all initialized scalar types and all access
507 -- types. Packed bit arrays of size up to 64 are represented using a
508 -- modular type with an initialization (to zero) and can be processed
509 -- like other initialized scalar types.
511 -- If the type is controlled, code to attach the object to a
512 -- finalization chain is generated at the point of declaration,
513 -- and therefore the elaboration of the object cannot be delayed:
514 -- the address expression must be a constant.
518 and then
522 or else
526 or else
529 or else
531 and then
533 then
536 -- Otherwise, we require the address clause to be constant because
537 -- the call to the initialization procedure (or the attach code) has
538 -- to happen at the point of the declaration.
540 else
547 then
553 -----------------------------
554 -- Check_Compile_Time_Size --
555 -----------------------------
560 -- Sets the compile time known size (32 bits or less) in the Esize
561 -- field, of T checking for a size clause that was given which attempts
562 -- to give a smaller size.
565 -- Recursive function that does all the work
568 -- If T is a constrained subtype, its size is not known if any of its
569 -- discriminant constraints is not static and it is not a null record.
570 -- The test is conservative and doesn't check that the components are
571 -- in fact constrained by non-static discriminant values. Could be made
572 -- more precise ???
574 --------------------
575 -- Set_Small_Size --
576 --------------------
579 begin
586 Error_Msg_NE
594 -- Set sizes if not set already
596 else
607 ----------------
608 -- Size_Known --
609 ----------------
618 begin
622 -- Always True for scalar types. This is true even for generic formal
623 -- scalar types. We used to return False in the latter case, but the
624 -- size is known at compile time, even in the template, we just do
625 -- not know the exact size but that's not the point of this routine.
629 then
632 -- Array types
636 -- String literals always have known size, and we can set it
643 -- Unconstrained types never have known at compile time size
648 -- Don't do any recursion on type with error posted, since we may
649 -- have a malformed type that leads us into a loop.
654 -- Otherwise if component size unknown, then array size unknown
660 -- Check for all indexes static, and also compute possible size
661 -- (in case it is less than 32 and may be packable).
663 declare
667 begin
676 else
684 then
687 else
692 else
704 -- Access types always have known at compile time sizes
709 -- For non-generic private types, go to underlying type if present
714 then
715 -- Don't do any recursion on type with error posted, since we may
716 -- have a malformed type that leads us into a loop.
720 else
724 -- Record types
728 -- A class-wide type is never considered to have a known size
733 -- A subtype of a variant record must not have non-static
734 -- discriminanted components.
738 then
741 -- Don't do any recursion on type with error posted, since we may
742 -- have a malformed type that leads us into a loop.
748 -- Now look at the components of the record
750 declare
751 -- The following two variables are used to keep track of the
752 -- size of packed records if we can tell the size of the packed
753 -- record in the front end. Packed_Size_Known is True if so far
754 -- we can figure out the size. It is initialized to True for a
755 -- packed record, unless the record has discriminants. The
756 -- reason we eliminate the discriminated case is that we don't
757 -- know the way the back end lays out discriminated packed
758 -- records. If Packed_Size_Known is True, then Packed_Size is
759 -- the size in bits so far.
767 begin
768 -- Test for variant part present
774 N_Record_Definition
778 then
779 -- If variant part is present, and type is unconstrained,
780 -- then we must have defaulted discriminants, or a size
781 -- clause must be present for the type, or else the size
782 -- is definitely not known at compile time.
785 and then
786 No (Discriminant_Default_Value
789 then
794 -- Loop through components
800 -- We do not know the packed size if there is a component
801 -- clause present (we possibly could, but this would only
802 -- help in the case of a record with partial rep clauses.
803 -- That's because in the case of full rep clauses, the
804 -- size gets figured out anyway by a different circuit).
810 -- We need to identify a component that is an array where
811 -- the index type is an enumeration type with non-standard
812 -- representation, and some bound of the type depends on a
813 -- discriminant.
815 -- This is because gigi computes the size by doing a
816 -- substitution of the appropriate discriminant value in
817 -- the size expression for the base type, and gigi is not
818 -- clever enough to evaluate the resulting expression (which
819 -- involves a call to rep_to_pos) at compile time.
821 -- It would be nice if gigi would either recognize that
822 -- this expression can be computed at compile time, or
823 -- alternatively figured out the size from the subtype
824 -- directly, where all the information is at hand ???
828 then
829 declare
837 begin
844 then
850 then
855 then
865 -- Clearly size of record is not known if the size of one of
866 -- the components is not known.
872 -- Accumulate packed size if possible
876 -- We can only deal with elementary types, since for
877 -- non-elementary components, alignment enters into the
878 -- picture, and we don't know enough to handle proper
879 -- alignment in this context. Packed arrays count as
880 -- elementary if the representation is a modular type.
885 and then Is_Modular_Integer_Type
887 then
888 -- If RM_Size is known and static, then we can
889 -- keep accumulating the packed size.
893 -- A little glitch, to be removed sometime ???
894 -- gigi does not understand zero sizes yet.
899 -- Normal case where we can keep accumulating the
900 -- packed array size.
902 else
906 -- If we have a field whose RM_Size is not known then
907 -- we can't figure out the packed size here.
909 else
913 -- If we have a non-elementary type we can't figure out
914 -- the packed array size (alignment issues).
916 else
931 -- All other cases, size not known at compile time
933 else
938 -------------------------------------
939 -- Static_Discriminated_Components --
940 -------------------------------------
942 function Static_Discriminated_Components
944 is
947 begin
951 then
965 -- Start of processing for Check_Compile_Time_Size
967 begin
971 -----------------------------
972 -- Check_Debug_Info_Needed --
973 -----------------------------
976 begin
981 or else Debug_Generated_Code
982 or else Debug_Flag_VV
984 then
989 ----------------------------
990 -- Check_Strict_Alignment --
991 ----------------------------
996 begin
1015 then
1025 -------------------------
1026 -- Check_Unsigned_Type --
1027 -------------------------
1034 begin
1039 -- Do not attempt to analyze case where range was in error
1045 -- The situation that is non trivial is something like
1047 -- subtype x1 is integer range -10 .. +10;
1048 -- subtype x2 is x1 range 0 .. V1;
1049 -- subtype x3 is x2 range V2 .. V3;
1050 -- subtype x4 is x3 range V4 .. V5;
1052 -- where Vn are variables. Here the base type is signed, but we still
1053 -- know that x4 is unsigned because of the lower bound of x2.
1055 -- The only way to deal with this is to look up the ancestor chain
1058 loop
1073 else
1076 -- If no ancestor had a static lower bound, go to base type
1080 -- Note: the reason we still check for a compile time known
1081 -- value for the base type is that at least in the case of
1082 -- generic formals, we can have bounds that fail this test,
1083 -- and there may be other cases in error situations.
1095 then
1105 -----------------------------
1106 -- Expand_Atomic_Aggregate --
1107 -----------------------------
1114 begin
1119 then
1120 Temp :=
1124 New_N :=
1134 -- To prevent the temporary from being constant-folded (which would
1135 -- lead to the same piecemeal assignment on the original target)
1136 -- indicate to the back-end that the temporary is a variable with
1137 -- real storage. See description of this flag in Einfo, and the notes
1138 -- on N_Assignment_Statement and N_Object_Declaration in Sinfo.
1144 ----------------
1145 -- Freeze_All --
1146 ----------------
1148 -- Note: the easy coding for this procedure would be to just build a
1149 -- single list of freeze nodes and then insert them and analyze them
1150 -- all at once. This won't work, because the analysis of earlier freeze
1151 -- nodes may recursively freeze types which would otherwise appear later
1152 -- on in the freeze list. So we must analyze and expand the freeze nodes
1153 -- as they are generated.
1161 -- This is the internal recursive routine that does freezing of entities
1162 -- (but NOT the analysis of default expressions, which should not be
1163 -- recursive, we don't want to analyze those till we are sure that ALL
1164 -- the types are frozen).
1166 --------------------
1167 -- Freeze_All_Ent --
1168 --------------------
1170 procedure Freeze_All_Ent
1173 is
1179 -- If freeze nodes are present, insert and analyze, and reset cursor
1180 -- for next insertion.
1182 -------------------
1183 -- Process_Flist --
1184 -------------------
1187 begin
1194 else
1200 -- Start or processing for Freeze_All_Ent
1202 begin
1206 -- If the entity is an inner package which is not a package
1207 -- renaming, then its entities must be frozen at this point. Note
1208 -- that such entities do NOT get frozen at the end of the nested
1209 -- package itself (only library packages freeze).
1211 -- Same is true for task declarations, where anonymous records
1212 -- created for entry parameters must be frozen.
1218 then
1228 and then
1230 or else
1232 then
1235 End_Scope;
1237 -- For a derived tagged type, we must ensure that all the
1238 -- primitive operations of the parent have been frozen, so that
1239 -- their addresses will be in the parent's dispatch table at the
1240 -- point it is inherited.
1246 then
1247 declare
1254 begin
1262 then
1264 Process_Flist;
1274 Process_Flist;
1277 -- If an incomplete type is still not frozen, this may be a
1278 -- premature freezing because of a body declaration that follows.
1279 -- Indicate where the freezing took place.
1281 -- If the freezing is caused by the end of the current declarative
1282 -- part, it is a Taft Amendment type, and there is no error.
1286 then
1287 declare
1290 begin
1297 and then
1299 then
1301 Error_Msg_NE
1312 -- Start of processing for Freeze_All
1314 begin
1317 -- Now that all types are frozen, we can deal with default expressions
1318 -- that require us to build a default expression functions. This is the
1319 -- point at which such functions are constructed (after all types that
1320 -- might be used in such expressions have been frozen).
1322 -- We also add finalization chains to access types whose designated
1323 -- types are controlled. This is normally done when freezing the type,
1324 -- but this misses recursive type definitions where the later members
1325 -- of the recursion introduce controlled components.
1327 -- Loop through entities
1345 and then
1347 = N_Subprogram_Renaming_Declaration
1348 then
1349 Build_And_Analyze_Renamed_Body
1355 and then
1357 or else
1359 then
1360 declare
1362 begin
1369 then
1382 then
1390 -----------------------
1391 -- Freeze_And_Append --
1392 -----------------------
1394 procedure Freeze_And_Append
1398 is
1400 begin
1404 else
1410 -------------------
1411 -- Freeze_Before --
1412 -------------------
1416 begin
1422 -------------------
1423 -- Freeze_Entity --
1424 -------------------
1436 -- Check that an Access or Unchecked_Access attribute with a prefix
1437 -- which is the current instance type can only be applied when the type
1438 -- is limited.
1441 -- If Loc is a freeze_entity that appears after the last declaration
1442 -- in the scope, inhibit error messages on late completion.
1445 -- Freeze each component, handle some representation clauses, and freeze
1446 -- primitive operations if this is a tagged type.
1448 ----------------------------
1449 -- After_Last_Declaration --
1450 ----------------------------
1454 begin
1460 else
1463 else
1468 ----------------------------
1469 -- Check_Current_Instance --
1470 ----------------------------
1480 -- Process routine to apply check to given node
1482 -------------
1483 -- Process --
1484 -------------
1487 begin
1491 or else
1496 then
1497 Error_Msg_N
1500 else
1510 -- Start of processing for Check_Current_Instance
1512 begin
1513 -- In Ada95, the (imprecise) rule is that the current instance of a
1514 -- limited type is aliased. In Ada2005, limitedness must be explicit:
1515 -- either a tagged type, or a limited record.
1518 and then
1521 then
1526 then
1529 else
1534 ------------------------
1535 -- Freeze_Record_Type --
1536 ------------------------
1548 -- Set True if we find at least one component with no component
1549 -- clause (used to warn about useless Pack pragmas).
1552 -- Set True if we find at least one component with a component
1553 -- clause (used to warn about useless Bit_Order pragmas).
1556 -- If N is an allocator, possibly wrapped in one or more level of
1557 -- qualified expression(s), return the inner allocator node, else
1558 -- return Empty.
1561 -- If the component subtype is an access to a constrained subtype of
1562 -- an already frozen type, make the subtype frozen as well. It might
1563 -- otherwise be frozen in the wrong scope, and a freeze node on
1564 -- subtype has no effect. Similarly, if the component subtype is a
1565 -- regular (not protected) access to subprogram, set the anonymous
1566 -- subprogram type to frozen as well, to prevent an out-of-scope
1567 -- freeze node at some eventual point of call. Protected operations
1568 -- are handled elsewhere.
1570 ---------------------
1571 -- Check_Allocator --
1572 ---------------------
1576 begin
1578 loop
1583 else
1589 -----------------
1590 -- Check_Itype --
1591 -----------------
1596 begin
1599 then
1602 -- In addition, add an Itype_Reference to ensure that the
1603 -- access subtype is elaborated early enough. This cannot be
1604 -- done if the subtype may depend on discriminants.
1609 then
1615 else
1622 then
1627 -- Start of processing for Freeze_Record_Type
1629 begin
1630 -- If this is a subtype of a controlled type, declared without a
1631 -- constraint, the _controller may not appear in the component list
1632 -- if the parent was not frozen at the point of subtype declaration.
1633 -- Inherit the _controller component now.
1637 then
1640 then
1643 -- If this is an internal type without a declaration, as for
1644 -- record component, the base type may not yet be frozen, and its
1645 -- controller has not been created. Add an explicit freeze node
1646 -- for the itype, so it will be frozen after the base type. This
1647 -- freeze node is used to communicate with the expander, in order
1648 -- to create the controller for the enclosing record, and it is
1649 -- deleted afterwards (see exp_ch3). It must not be created when
1650 -- expansion is off, because it might appear in the wrong context
1651 -- for the back end.
1655 and then
1657 N_Component_Declaration
1658 and then Expander_Active
1659 then
1664 -- Freeze components and embedded subtypes
1670 -- First handle the (real) component case
1674 then
1675 declare
1678 begin
1679 -- Freezing a record type freezes the type of each of its
1680 -- components. However, if the type of the component is
1681 -- part of this record, we do not want or need a separate
1682 -- Freeze_Node. Note that Is_Itype is wrong because that's
1683 -- also set in private type cases. We also can't check for
1684 -- the Scope being exactly Rec because of private types and
1685 -- record extensions.
1690 then
1696 -- Check for error of component clause given for variable
1697 -- sized type. We have to delay this test till this point,
1698 -- since the component type has to be frozen for us to know
1699 -- if it is variable length. We omit this test in a generic
1700 -- context, it will be applied at instantiation time.
1708 elsif not
1709 Size_Known_At_Compile_Time
1711 then
1712 Error_Msg_N
1717 else
1721 -- Case of component requires byte alignment
1725 -- Set the enclosing record to also require byte align
1729 -- Check for component clause that is inconsistent with
1730 -- the required byte boundary alignment.
1735 then
1736 Error_Msg_N
1742 -- If component clause is present, then deal with the non-
1743 -- default bit order case for Ada 95 mode. The required
1744 -- processing for Ada 2005 mode is handled separately after
1745 -- processing all components.
1747 -- We only do this processing for the base type, and in
1748 -- fact that's important, since otherwise if there are
1749 -- record subtypes, we could reverse the bits once for
1750 -- each subtype, which would be incorrect.
1756 then
1757 declare
1770 begin
1771 -- Cases where field goes over storage unit boundary
1775 -- Allow multi-byte field but generate warning
1779 then
1780 Error_Msg_N
1785 Error_Msg_N
1788 else
1789 Error_Msg_N
1794 -- Do not allow non-contiguous field
1796 else
1797 Error_Msg_N
1800 Error_Msg_N
1805 -- Case where field fits in one storage unit
1807 else
1808 -- Give warning if suspicious component clause
1811 and then Warn_On_Reverse_Bit_Order
1812 then
1813 Error_Msg_N
1816 Error_Msg_Uint_1 :=
1818 System_Storage_Unit;
1819 Error_Msg_N
1824 -- Here is where we fix up the Component_Bit_Offset
1825 -- value to account for the reverse bit order.
1826 -- Some examples of what needs to be done are:
1828 -- First_Bit .. Last_Bit Component_Bit_Offset
1829 -- old new old new
1831 -- 0 .. 0 7 .. 7 0 7
1832 -- 0 .. 1 6 .. 7 0 6
1833 -- 0 .. 2 5 .. 7 0 5
1834 -- 0 .. 7 0 .. 7 0 4
1836 -- 1 .. 1 6 .. 6 1 6
1837 -- 1 .. 4 3 .. 6 1 3
1838 -- 4 .. 7 0 .. 3 4 0
1840 -- The general rule is that the first bit is
1841 -- is obtained by subtracting the old ending bit
1842 -- from storage_unit - 1.
1844 Set_Component_Bit_Offset
1850 Set_Normalized_First_Bit
1853 System_Storage_Unit);
1860 -- If the component is an Itype with Delayed_Freeze and is either
1861 -- a record or array subtype and its base type has not yet been
1862 -- frozen, we must remove this from the entity list of this
1863 -- record and put it on the entity list of the scope of its base
1864 -- type. Note that we know that this is not the type of a
1865 -- component since we cleared Has_Delayed_Freeze for it in the
1866 -- previous loop. Thus this must be the Designated_Type of an
1867 -- access type, which is the type of a component.
1875 then
1876 declare
1880 begin
1881 -- We have a pretty bad kludge here. Suppose Rec is subtype
1882 -- being defined in a subprogram that's created as part of
1883 -- the freezing of Rec'Base. In that case, we know that
1884 -- Comp'Base must have already been frozen by the time we
1885 -- get to elaborate this because Gigi doesn't elaborate any
1886 -- bodies until it has elaborated all of the declarative
1887 -- part. But Is_Frozen will not be set at this point because
1888 -- we are processing code in lexical order.
1890 -- We detect this case by going up the Scope chain of Rec
1891 -- and seeing if we have a subprogram scope before reaching
1892 -- the top of the scope chain or that of Comp'Base. If we
1893 -- do, then mark that Comp'Base will actually be frozen. If
1894 -- so, we merely undelay it.
1910 else
1913 else
1917 -- Insert in entity list of scope of base type (which
1918 -- must be an enclosing scope, because still unfrozen).
1924 -- If the component is an access type with an allocator as default
1925 -- value, the designated type will be frozen by the corresponding
1926 -- expression in init_proc. In order to place the freeze node for
1927 -- the designated type before that for the current record type,
1928 -- freeze it now.
1930 -- Same process if the component is an array of access types,
1931 -- initialized with an aggregate. If the designated type is
1932 -- private, it cannot contain allocators, and it is premature
1933 -- to freeze the type, so we check for this as well.
1938 then
1939 declare
1943 begin
1946 -- If component is pointer to a classwide type, freeze
1947 -- the specific type in the expression being allocated.
1948 -- The expression may be a subtype indication, in which
1949 -- case freeze the subtype mark.
1951 if Is_Class_Wide_Type
1953 then
1955 Freeze_And_Append
1957 elsif
1959 then
1960 Freeze_And_Append
1968 else
1969 Freeze_And_Append
1977 then
1986 and then Is_Fully_Defined
1988 then
1989 Freeze_And_Append
1990 (Designated_Type
1998 -- Deal with pragma Bit_Order
2002 ADC :=
2004 Error_Msg_N
2006 Error_Msg_N
2009 -- Here is where we do Ada 2005 processing for bit order (the Ada
2010 -- 95 case was already taken care of above).
2017 -- Set OK_To_Reorder_Components depending on debug flags
2021 then
2023 or else
2025 then
2030 -- Check for useless pragma Pack when all components placed. We only
2031 -- do this check for record types, not subtypes, since a subtype may
2032 -- have all its components placed, and it still makes perfectly good
2033 -- sense to pack other subtypes or the parent type. We do not give
2034 -- this warning if Optimize_Alignment is set to Space, since the
2035 -- pragma Pack does have an effect in this case (it always resets
2036 -- the alignment to one).
2040 and then not Unplaced_Component
2042 then
2043 -- Reset packed status. Probably not necessary, but we do it so
2044 -- that there is no chance of the back end doing something strange
2045 -- with this redundant indication of packing.
2049 -- Give warning if redundant constructs warnings on
2052 Error_Msg_N
2058 -- If this is the record corresponding to a remote type, freeze the
2059 -- remote type here since that is what we are semantically freezing.
2060 -- This prevents the freeze node for that type in an inner scope.
2062 -- Also, Check for controlled components and unchecked unions.
2063 -- Finally, enforce the restriction that access attributes with a
2064 -- current instance prefix can only apply to limited types.
2068 Freeze_And_Append
2078 and then Present
2080 and then Has_Controlled_Component
2082 then
2093 -- Scan component declaration for likely misuses of current
2094 -- instance, either in a constraint or a default expression.
2105 -- For first subtypes, check if there are any fixed-point fields with
2106 -- component clauses, where we must check the size. This is not done
2107 -- till the freeze point, since for fixed-point types, we do not know
2108 -- the size until the type is frozen. Similar processing applies to
2109 -- bit packed arrays.
2117 or else
2119 then
2120 Check_Size
2124 Junk);
2131 -- Generate warning for applying C or C++ convention to a record
2132 -- with discriminants. This is suppressed for the unchecked union
2133 -- case, since the whole point in this case is interface C. We also
2134 -- do not generate this within instantiations, since we will have
2135 -- generated a message on the template.
2140 or else
2143 and then not In_Instance
2146 then
2147 declare
2151 begin
2156 Error_Msg_N
2158 else
2159 Error_Msg_N
2163 Error_Msg_NE
2170 -- Start of processing for Freeze_Entity
2172 begin
2173 -- We are going to test for various reasons why this entity need not be
2174 -- frozen here, but in the case of an Itype that's defined within a
2175 -- record, that test actually applies to the record.
2181 then
2185 -- Do not freeze if already frozen since we only need one freeze node
2190 -- It is improper to freeze an external entity within a generic because
2191 -- its freeze node will appear in a non-valid context. The entity will
2192 -- be frozen in the proper scope after the current generic is analyzed.
2197 -- Do not freeze a global entity within an inner scope created during
2198 -- expansion. A call to subprogram E within some internal procedure
2199 -- (a stream attribute for example) might require freezing E, but the
2200 -- freeze node must appear in the same declarative part as E itself.
2201 -- The two-pass elaboration mechanism in gigi guarantees that E will
2202 -- be frozen before the inner call is elaborated. We exclude constants
2203 -- from this test, because deferred constants may be frozen early, and
2204 -- must be diagnosed (e.g. in the case of a deferred constant being used
2205 -- in a default expression). If the enclosing subprogram comes from
2206 -- source, or is a generic instance, then the freeze point is the one
2207 -- mandated by the language, and we freeze the entity. A subprogram that
2208 -- is a child unit body that acts as a spec does not have a spec that
2209 -- comes from source, but can only come from source.
2214 then
2215 declare
2218 begin
2224 then
2226 else
2235 -- Similarly, an inlined instance body may make reference to global
2236 -- entities, but these references cannot be the proper freezing point
2237 -- for them, and in the absence of inlining freezing will take place in
2238 -- their own scope. Normally instance bodies are analyzed after the
2239 -- enclosing compilation, and everything has been frozen at the proper
2240 -- place, but with front-end inlining an instance body is compiled
2241 -- before the end of the enclosing scope, and as a result out-of-order
2242 -- freezing must be prevented.
2244 elsif Front_End_Inlining
2245 and then In_Instance_Body
2247 then
2248 declare
2251 begin
2255 else
2266 -- Here to freeze the entity
2271 -- Case of entity being frozen is other than a type
2275 -- If entity is exported or imported and does not have an external
2276 -- name, now is the time to provide the appropriate default name.
2277 -- Skip this if the entity is stubbed, since we don't need a name
2278 -- for any stubbed routine.
2283 then
2284 Set_Encoded_Interface_Name
2287 -- Special processing for atomic objects appearing in object decls
2292 then
2293 declare
2296 begin
2297 -- If expression is an aggregate, assign to a temporary to
2298 -- ensure that the actual assignment is done atomically rather
2299 -- than component-wise (the assignment to the temp may be done
2300 -- component-wise, but that is harmless).
2305 -- If the expression is a reference to a record or array object
2306 -- entity, then reset Is_True_Constant to False so that the
2307 -- compiler will not optimize away the intermediate object,
2308 -- which we need in this case for the same reason (to ensure
2309 -- that the actual assignment is atomic, rather than
2310 -- component-wise).
2314 or else
2316 then
2322 -- For a subprogram, freeze all parameter types and also the return
2323 -- type (RM 13.14(14)). However skip this for internal subprograms.
2324 -- This is also the point where any extra formal parameters are
2325 -- created since we now know whether the subprogram will use
2326 -- a foreign convention.
2330 declare
2335 begin
2336 -- Loop through formals
2348 then
2349 -- If the type of a formal is incomplete, subprogram
2350 -- is being frozen prematurely. Within an instance
2351 -- (but not within a wrapper package) this is an
2352 -- an artifact of our need to regard the end of an
2353 -- instantiation as a freeze point. Otherwise it is
2354 -- a definite error.
2356 -- and then not Is_Wrapper_Package (Current_Scope) ???
2362 elsif not After_Last_Declaration
2363 and then not Freezing_Library_Level_Tagged_Type
2364 then
2366 Error_Msg
2368 Loc);
2372 -- Check suspicious parameter for C function. These tests
2373 -- apply only to exported/imported subprograms.
2375 if Warn_On_Export_Import
2378 or else
2385 then
2388 -- Check suspicious use of fat C pointer
2392 then
2393 Error_Msg_N
2397 -- Check suspicious return of boolean
2401 then
2402 Error_Msg_N
2406 -- Check suspicious tagged type
2410 and then
2411 Is_Tagged_Type
2414 then
2415 Error_Msg_N
2419 -- Check wrong convention subprogram pointer
2423 then
2424 Error_Msg_N
2428 Error_Msg_NE
2436 -- Check for unconstrained array in exported foreign
2437 -- convention case.
2443 and then Warn_On_Export_Import
2444 then
2447 -- If this is an inherited operation, place the
2448 -- warning on the derived type declaration, rather
2449 -- than on the original subprogram.
2452 N_Full_Type_Declaration
2453 then
2457 Error_Msg_NE
2460 else
2464 Error_Msg_NE
2467 Error_Msg_NE
2473 -- Ada 2005 (AI-326): Check wrong use of tag incomplete
2474 -- types with unknown discriminants. For example:
2476 -- type T (<>) is tagged;
2477 -- procedure P (X : access T); -- ERROR
2478 -- procedure P (X : T); -- ERROR
2489 and then Unknown_Discriminants_Present
2492 then
2493 Error_Msg_N
2497 -- If the formal is an anonymous_access_to_subprogram
2498 -- freeze the subprogram type as well, to prevent
2499 -- scope anomalies in gigi, because there is no other
2500 -- clear point at which it could be frozen.
2504 then
2512 -- Case of function
2516 -- Freeze return type
2521 -- Check suspicious return type for C function
2523 if Warn_On_Export_Import
2525 or else
2528 then
2529 -- Check suspicious return of fat C pointer
2535 then
2536 Error_Msg_N
2540 -- Check suspicious return of boolean
2546 then
2547 Error_Msg_N
2551 -- Check suspicious return tagged type
2555 and then
2556 Is_Tagged_Type
2561 then
2562 Error_Msg_N
2566 -- Check return of wrong convention subprogram pointer
2572 then
2573 Error_Msg_N
2577 Error_Msg_NE
2587 and then Warn_On_Export_Import
2590 then
2591 Error_Msg_N
2595 -- Ada 2005 (AI-326): Check wrong use of tagged
2596 -- incomplete type
2597 --
2598 -- type T is tagged;
2599 -- function F (X : Boolean) return T; -- ERROR
2605 then
2606 Error_Msg_N
2608 E);
2614 -- Must freeze its parent first if it is a derived subprogram
2620 -- We don't freeze internal subprograms, because we don't normally
2621 -- want addition of extra formals or mechanism setting to happen
2622 -- for those. However we do pass through predefined dispatching
2623 -- cases, since extra formals may be needed in some cases, such as
2624 -- for the stream 'Input function (build-in-place formals).
2628 then
2632 -- Here for other than a subprogram or type
2634 else
2635 -- If entity has a type, and it is not a generic unit, then
2636 -- freeze it first (RM 13.14(10)).
2640 then
2644 -- Special processing for objects created by object declaration
2648 -- For object created by object declaration, perform required
2649 -- categorization (preelaborate and pure) checks. Defer these
2650 -- checks to freeze time since pragma Import inhibits default
2651 -- initialization and thus pragma Import affects these checks.
2655 -- If there is an address clause, check that it is valid
2659 -- If the object needs any kind of default initialization, an
2660 -- error must be issued if No_Default_Initialization applies.
2661 -- The check doesn't apply to imported objects, which are not
2662 -- ever default initialized, and is why the check is deferred
2663 -- until freezing, at which point we know if Import applies.
2667 and then
2672 or else
2675 then
2676 Check_Restriction
2680 -- For imported objects, set Is_Public unless there is also an
2681 -- address clause, which means that there is no external symbol
2682 -- needed for the Import (Is_Public may still be set for other
2683 -- unrelated reasons). Note that we delayed this processing
2684 -- till freeze time so that we can be sure not to set the flag
2685 -- if there is an address clause. If there is such a clause,
2686 -- then the only purpose of the Import pragma is to suppress
2687 -- implicit initialization.
2691 then
2695 -- For convention C objects of an enumeration type, warn if
2696 -- the size is not integer size and no explicit size given.
2697 -- Skip warning for Boolean, and Character, assume programmer
2698 -- expects 8-bit sizes for these cases.
2701 or else
2708 then
2710 Error_Msg_N
2712 E);
2717 -- Check that a constant which has a pragma Volatile[_Components]
2718 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
2720 -- Note: Atomic[_Components] also sets Volatile[_Components]
2725 then
2726 -- Make sure we actually have a pragma, and have not merely
2727 -- inherited the indication from elsewhere (e.g. an address
2728 -- clause, which is not good enough in RM terms!)
2731 or else
2733 then
2734 Error_Msg_N
2739 or else
2741 then
2742 Error_Msg_N
2748 -- Static objects require special handling
2752 then
2756 -- Remaining step is to layout objects
2759 or else
2761 or else
2763 or else
2765 then
2770 -- Case of a type or subtype being frozen
2772 else
2773 -- We used to check here that a full type must have preelaborable
2774 -- initialization if it completes a private type specified with
2775 -- pragma Preelaborable_Intialization, but that missed cases where
2776 -- the types occur within a generic package, since the freezing
2777 -- that occurs within a containing scope generally skips traversal
2778 -- of a generic unit's declarations (those will be frozen within
2779 -- instances). This check was moved to Analyze_Package_Specification.
2781 -- The type may be defined in a generic unit. This can occur when
2782 -- freezing a generic function that returns the type (which is
2783 -- defined in a parent unit). It is clearly meaningless to freeze
2784 -- this type. However, if it is a subtype, its size may be determi-
2785 -- nable and used in subsequent checks, so might as well try to
2786 -- compute it.
2790 then
2795 -- Deal with special cases of freezing for subtype
2799 -- Before we do anything else, a specialized test for the case of
2800 -- a size given for an array where the array needs to be packed,
2801 -- but was not so the size cannot be honored. This would of course
2802 -- be caught by the backend, and indeed we don't catch all cases.
2803 -- The point is that we can give a better error message in those
2804 -- cases that we do catch with the circuitry here. Also if pragma
2805 -- Implicit_Packing is set, this is where the packing occurs.
2807 -- The reason we do this so early is that the processing in the
2808 -- automatic packing case affects the layout of the base type, so
2809 -- it must be done before we freeze the base type.
2812 declare
2816 begin
2817 -- Check enabling conditions. These are straightforward
2818 -- except for the test for a limited composite type. This
2819 -- eliminates the rare case of a array of limited components
2820 -- where there are issues of whether or not we can go ahead
2821 -- and pack the array (since we can't freely pack and unpack
2822 -- arrays if they are limited).
2824 -- Note that we check the root type explicitly because the
2825 -- whole point is we are doing this test before we have had
2826 -- a chance to freeze the base type (and it is that freeze
2827 -- action that causes stuff to be inherited).
2839 then
2846 then
2847 declare
2857 -- What we are looking for here is the situation where
2858 -- the RM_Size given would be exactly right if there
2859 -- was a pragma Pack (resulting in the component size
2860 -- being the same as the RM_Size). Furthermore, the
2861 -- component type size must be an odd size (not a
2862 -- multiple of storage unit)
2864 begin
2867 then
2868 -- For implicit packing mode, just set the
2869 -- component size silently
2877 -- Otherwise give an error message
2879 else
2880 Error_Msg_NE
2882 Error_Msg_N
2893 -- If ancestor subtype present, freeze that first. Note that this
2894 -- will also get the base type frozen.
2901 -- Otherwise freeze the base type of the entity before freezing
2902 -- the entity itself (RM 13.14(15)).
2908 -- For a derived type, freeze its parent type first (RM 13.14(15))
2915 -- For array type, freeze index types and component type first
2916 -- before freezing the array (RM 13.14(15)).
2919 declare
2923 -- Set true if any of the index types is an enumeration type
2924 -- with a non-standard representation.
2926 begin
2935 then
2942 -- Processing that is done only for base types
2946 -- Propagate flags for component type
2950 then
2958 -- If packing was requested or if the component size was set
2959 -- explicitly, then see if bit packing is required. This
2960 -- processing is only done for base types, since all the
2961 -- representation aspects involved are type-related. This
2962 -- is not just an optimization, if we start processing the
2963 -- subtypes, they interfere with the settings on the base
2964 -- type (this is because Is_Packed has a slightly different
2965 -- meaning before and after freezing).
2967 declare
2971 begin
2975 then
2984 else
2987 -- We can set the component size if it is less than
2988 -- 16, rounding it up to the next storage unit size.
2994 else
2998 -- Set component size up to match alignment if it
2999 -- would otherwise be less than the alignment. This
3000 -- deals with cases of types whose alignment exceeds
3001 -- their size (padded types).
3004 declare
3006 begin
3014 -- Case of component size that may result in packing
3017 declare
3023 Get_Attribute_Definition_Clause
3025 begin
3026 -- Warn if we have pack and component size so that
3027 -- the pack is ignored.
3029 -- Note: here we must check for the presence of a
3030 -- component size before checking for a Pack pragma
3031 -- to deal with the case where the array type is a
3032 -- derived type whose parent is currently private.
3036 then
3038 Error_Msg_NE
3041 Error_Msg_N
3043 Pack_Pragma);
3046 -- Set component size if not already set by a
3047 -- component size clause.
3053 -- Check for base type of 8, 16, 32 bits, where an
3054 -- unsigned subtype has a length one less than the
3055 -- base type (e.g. Natural subtype of Integer).
3057 -- In such cases, if a component size was not set
3058 -- explicitly, then generate a warning.
3062 and then
3065 then
3069 Error_Msg_N
3072 Error_Msg_N
3078 -- Actual packing is not needed for 8, 16, 32, 64.
3079 -- Also not needed for 24 if alignment is 1.
3086 then
3087 -- Here the array was requested to be packed,
3088 -- but the packing request had no effect, so
3089 -- Is_Packed is reset.
3091 -- Note: semantically this means that we lose
3092 -- track of the fact that a derived type
3093 -- inherited a pragma Pack that was non-
3094 -- effective, but that seems fine.
3096 -- We regard a Pack pragma as a request to set
3097 -- a representation characteristic, and this
3098 -- request may be ignored.
3102 -- In all other cases, packing is indeed needed
3104 else
3113 -- Processing that is done only for subtypes
3115 else
3116 -- Acquire alignment from base type
3124 -- For bit-packed arrays, check the size
3128 then
3129 declare
3135 begin
3136 -- It is not clear if it is possible to have no size
3137 -- clause at this stage, but it is not worth worrying
3138 -- about. Post error on the entity name in the size
3139 -- clause if present, else on the type entity itself.
3143 else
3149 -- If any of the index types was an enumeration type with
3150 -- a non-standard rep clause, then we indicate that the
3151 -- array type is always packed (even if it is not bit packed).
3160 -- If the array is packed, we must create the packed array
3161 -- type to be used to actually implement the type. This is
3162 -- only needed for real array types (not for string literal
3163 -- types, since they are present only for the front end).
3167 then
3171 -- Size information of packed array type is copied to the
3172 -- array type, since this is really the representation. But
3173 -- do not override explicit existing size values. If the
3174 -- ancestor subtype is constrained the packed_array_type
3175 -- will be inherited from it, but the size may have been
3176 -- provided already, and must not be overridden either.
3179 and then
3182 then
3192 -- For non-packed arrays set the alignment of the array to the
3193 -- alignment of the component type if it is unknown. Skip this
3194 -- in atomic case (atomic arrays may need larger alignments).
3203 then
3208 -- For a class-wide type, the corresponding specific type is
3209 -- frozen as well (RM 13.14(15))
3214 -- If the base type of the class-wide type is still incomplete,
3215 -- the class-wide remains unfrozen as well. This is legal when
3216 -- E is the formal of a primitive operation of some other type
3217 -- which is being frozen.
3224 -- If the Class_Wide_Type is an Itype (when type is the anonymous
3225 -- parent of a derived type) and it is a library-level entity,
3226 -- generate an itype reference for it. Otherwise, its first
3227 -- explicit reference may be in an inner scope, which will be
3228 -- rejected by the back-end.
3232 then
3233 declare
3236 begin
3240 else
3246 -- The equivalent type associated with a class-wide subtype needs
3247 -- to be frozen to ensure that its layout is done. Class-wide
3248 -- subtypes are currently only frozen on targets requiring
3249 -- front-end layout (see New_Class_Wide_Subtype and
3250 -- Make_CW_Equivalent_Type in exp_util.adb).
3254 then
3258 -- For a record (sub)type, freeze all the component types (RM
3259 -- 13.14(15). We test for E_Record_(sub)Type here, rather than using
3260 -- Is_Record_Type, because we don't want to attempt the freeze for
3261 -- the case of a private type with record extension (we will do that
3262 -- later when the full type is frozen).
3266 then
3269 -- For a concurrent type, freeze corresponding record type. This
3270 -- does not correspond to any specific rule in the RM, but the
3271 -- record type is essentially part of the concurrent type.
3272 -- Freeze as well all local entities. This includes record types
3273 -- created for entry parameter blocks, and whatever local entities
3274 -- may appear in the private part.
3278 Freeze_And_Append
3291 then
3301 -- Private types are required to point to the same freeze node as
3302 -- their corresponding full views. The freeze node itself has to
3303 -- point to the partial view of the entity (because from the partial
3304 -- view, we can retrieve the full view, but not the reverse).
3305 -- However, in order to freeze correctly, we need to freeze the full
3306 -- view. If we are freezing at the end of a scope (or within the
3307 -- scope of the private type), the partial and full views will have
3308 -- been swapped, the full view appears first in the entity chain and
3309 -- the swapping mechanism ensures that the pointers are properly set
3310 -- (on scope exit).
3312 -- If we encounter the partial view before the full view (e.g. when
3313 -- freezing from another scope), we freeze the full view, and then
3314 -- set the pointers appropriately since we cannot rely on swapping to
3315 -- fix things up (subtypes in an outer scope might not get swapped).
3319 then
3320 -- The construction of the dispatch table associated with library
3321 -- level tagged types forces freezing of all the primitives of the
3322 -- type, which may cause premature freezing of the partial view.
3323 -- For example:
3325 -- package Pkg is
3326 -- type T is tagged private;
3327 -- type DT is new T with private;
3328 -- procedure Prim (X : in out T; Y : in out DT'class);
3329 -- private
3330 -- type T is tagged null record;
3331 -- Obj : T;
3332 -- type DT is new T with null record;
3333 -- end;
3335 -- In this case the type will be frozen later by the usual
3336 -- mechanism: an object declaration, an instantiation, or the
3337 -- end of a declarative part.
3341 then
3345 -- Case of full view present
3349 -- If full view has already been frozen, then no further
3350 -- processing is required
3358 -- Otherwise freeze full view and patch the pointers so that
3359 -- the freeze node will elaborate both views in the back-end.
3361 else
3362 declare
3365 begin
3368 then
3369 Freeze_And_Append
3382 else
3383 -- {Incomplete,Private}_Subtypes with Full_Views
3384 -- constrained by discriminants.
3395 -- AI-117 requires that the convention of a partial view be the
3396 -- same as the convention of the full view. Note that this is a
3397 -- recognized breach of privacy, but it's essential for logical
3398 -- consistency of representation, and the lack of a rule in
3399 -- RM95 was an oversight.
3406 -- Size information is copied from the full view to the
3407 -- incomplete or private view for consistency.
3409 -- We skip this is the full view is not a type. This is very
3410 -- strange of course, and can only happen as a result of
3411 -- certain illegalities, such as a premature attempt to derive
3412 -- from an incomplete type.
3421 -- Case of no full view present. If entity is derived or subtype,
3422 -- it is safe to freeze, correctness depends on the frozen status
3423 -- of parent. Otherwise it is either premature usage, or a Taft
3424 -- amendment type, so diagnosis is at the point of use and the
3425 -- type might be frozen later.
3429 then
3432 else
3437 -- For access subprogram, freeze types of all formals, the return
3438 -- type was already frozen, since it is the Etype of the function.
3449 -- Ada 2005 (AI-326): Check wrong use of tag incomplete type
3451 -- type T is tagged;
3452 -- type Acc is access function (X : T) return T; -- ERROR
3458 then
3459 Error_Msg_N
3463 -- For access to a protected subprogram, freeze the equivalent type
3464 -- (however this is not set if we are not generating code or if this
3465 -- is an anonymous type used just for resolution).
3469 -- AI-326: Check wrong use of tagged incomplete types
3471 -- type T is tagged;
3472 -- type As3D is access protected
3473 -- function (X : Float) return T; -- ERROR
3475 declare
3478 begin
3489 then
3490 Error_Msg_N
3500 -- Generic types are never seen by the back-end, and are also not
3501 -- processed by the expander (since the expander is turned off for
3502 -- generic processing), so we never need freeze nodes for them.
3508 -- Some special processing for non-generic types to complete
3509 -- representation details not known till the freeze point.
3514 -- Some error checks required for ordinary fixed-point type. Defer
3515 -- these till the freeze-point since we need the small and range
3516 -- values. We only do these checks for base types
3520 then
3523 Error_Msg_N
3528 Error_Msg_N
3534 Error_Msg_N
3540 Error_Msg_N
3553 -- Check restriction for standard storage pool
3559 -- Deal with error message for pure access type. This is not an
3560 -- error in Ada 2005 if there is no pool (see AI-366).
3565 then
3569 Error_Msg_N
3573 Error_Msg_N
3576 else
3577 Error_Msg_N
3584 -- Case of composite types
3588 -- AI-117 requires that all new primitives of a tagged type must
3589 -- inherit the convention of the full view of the type. Inherited
3590 -- and overriding operations are defined to inherit the convention
3591 -- of their parent or overridden subprogram (also specified in
3592 -- AI-117), which will have occurred earlier (in Derive_Subprogram
3593 -- and New_Overloaded_Entity). Here we set the convention of
3594 -- primitives that are still convention Ada, which will ensure
3595 -- that any new primitives inherit the type's convention. Class-
3596 -- wide types can have a foreign convention inherited from their
3597 -- specific type, but are excluded from this since they don't have
3598 -- any associated primitives.
3603 then
3604 declare
3607 begin
3620 -- Generate primitive operation references for a tagged type
3624 then
3625 declare
3631 begin
3632 -- Handle subtypes
3636 then
3638 else
3642 -- Ada 2005 (AI-345): In case of concurrent type generate
3643 -- reference to the wrapper that allow us to dispatch calls
3644 -- through their implemented abstract interface types.
3646 -- The check for Present here is to protect against previously
3647 -- reported critical errors.
3651 then
3652 Prim_List := Primitive_Operations
3654 else
3658 -- Loop to generate references for primitive operations
3664 -- If the operation is derived, get the original for
3665 -- cross-reference purposes (it is the original for
3666 -- which we want the xref, and for which the comes
3667 -- from source test needs to be performed).
3681 -- Now that all types from which E may depend are frozen, see if the
3682 -- size is known at compile time, if it must be unsigned, or if
3683 -- strict alignment is required
3692 -- Do not allow a size clause for a type which does not have a size
3693 -- that is known at compile time
3697 then
3698 -- Suppress this message if errors posted on E, even if we are
3699 -- in all errors mode, since this is often a junk message
3702 Error_Msg_N
3708 -- Remaining process is to set/verify the representation information,
3709 -- in particular the size and alignment values. This processing is
3710 -- not required for generic types, since generic types do not play
3711 -- any part in code generation, and so the size and alignment values
3712 -- for such types are irrelevant.
3717 -- Otherwise we call the layout procedure
3719 else
3723 -- End of freeze processing for type entities
3726 -- Here is where we logically freeze the current entity. If it has a
3727 -- freeze node, then this is the point at which the freeze node is
3728 -- linked into the result list.
3732 -- If a freeze node is already allocated, use it, otherwise allocate
3733 -- a new one. The preallocation happens in the case of anonymous base
3734 -- types, where we preallocate so that we can set First_Subtype_Link.
3735 -- Note that we reset the Sloc to the current freeze location.
3741 else
3753 else
3757 -- A final pass over record types with discriminants. If the type
3758 -- has an incomplete declaration, there may be constrained access
3759 -- subtypes declared elsewhere, which do not depend on the discrimi-
3760 -- nants of the type, and which are used as component types (i.e.
3761 -- the full view is a recursive type). The designated types of these
3762 -- subtypes can only be elaborated after the type itself, and they
3763 -- need an itype reference.
3767 then
3768 declare
3773 begin
3784 then
3796 -- When a type is frozen, the first subtype of the type is frozen as
3797 -- well (RM 13.14(15)). This has to be done after freezing the type,
3798 -- since obviously the first subtype depends on its own base type.
3803 -- If we just froze a tagged non-class wide record, then freeze the
3804 -- corresponding class-wide type. This must be done after the tagged
3805 -- type itself is frozen, because the class-wide type refers to the
3806 -- tagged type which generates the class.
3811 then
3818 -- Special handling for subprograms
3822 -- If subprogram has address clause then reset Is_Public flag, since
3823 -- we do not want the backend to generate external references.
3827 then
3830 -- If no address clause and not intrinsic, then for imported
3831 -- subprogram in main unit, generate descriptor if we are in
3832 -- Propagate_Exceptions mode.
3834 elsif Propagate_Exceptions
3838 then
3848 -----------------------------
3849 -- Freeze_Enumeration_Type --
3850 -----------------------------
3853 begin
3854 -- By default, if no size clause is present, an enumeration type with
3855 -- Convention C is assumed to interface to a C enum, and has integer
3856 -- size. This applies to types. For subtypes, verify that its base
3857 -- type has no size clause either.
3863 then
3866 else
3867 -- If the enumeration type interfaces to C, and it has a size clause
3868 -- that specifies less than int size, it warrants a warning. The
3869 -- user may intend the C type to be an enum or a char, so this is
3870 -- not by itself an error that the Ada compiler can detect, but it
3871 -- it is a worth a heads-up. For Boolean and Character types we
3872 -- assume that the programmer has the proper C type in mind.
3879 then
3880 Error_Msg_N
3888 -----------------------
3889 -- Freeze_Expression --
3890 -----------------------
3901 -- This flag is set true if the entity must be frozen outside the
3902 -- current subprogram. This happens in the case of expander generated
3903 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
3904 -- not freeze all entities like other bodies, but which nevertheless
3905 -- may reference entities that have to be frozen before the body and
3906 -- obviously cannot be frozen inside the body.
3909 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
3910 -- it is the handled statement sequence of an expander-generated
3911 -- subprogram (init proc, stream subprogram, or renaming as body).
3912 -- If so, this is not a freezing context.
3914 -----------------
3915 -- In_Exp_Body --
3916 -----------------
3922 begin
3925 else
3932 else
3942 N_Subprogram_Renaming_Declaration)
3943 then
3945 else
3951 -- Start of processing for Freeze_Expression
3953 begin
3954 -- Immediate return if freezing is inhibited. This flag is set by the
3955 -- analyzer to stop freezing on generated expressions that would cause
3956 -- freezing if they were in the source program, but which are not
3957 -- supposed to freeze, since they are created.
3963 -- If expression is non-static, then it does not freeze in a default
3964 -- expression, see section "Handling of Default Expressions" in the
3965 -- spec of package Sem for further details. Note that we have to
3966 -- make sure that we actually have a real expression (if we have
3967 -- a subtype indication, we can't test Is_Static_Expression!)
3969 if In_Spec_Exp
3972 then
3976 -- Freeze type of expression if not frozen already
3984 -- Base type may be an derived numeric type that is frozen at
3985 -- the point of declaration, but first_subtype is still unfrozen.
3992 -- For entity name, freeze entity if not frozen already. A special
3993 -- exception occurs for an identifier that did not come from source.
3994 -- We don't let such identifiers freeze a non-internal entity, i.e.
3995 -- an entity that did come from source, since such an identifier was
3996 -- generated by the expander, and cannot have any semantic effect on
3997 -- the freezing semantics. For example, this stops the parameter of
3998 -- an initialization procedure from freezing the variable.
4005 then
4007 else
4011 -- For an allocator freeze designated type if not frozen already
4013 -- For an aggregate whose component type is an access type, freeze the
4014 -- designated type now, so that its freeze does not appear within the
4015 -- loop that might be created in the expansion of the aggregate. If the
4016 -- designated type is a private type without full view, the expression
4017 -- cannot contain an allocator, so the type is not frozen.
4028 then
4032 when N_Selected_Component |
4033 N_Indexed_Component |
4034 N_Slice =>
4047 then
4051 -- All done if nothing needs freezing
4056 then
4060 -- Loop for looking at the right place to insert the freeze nodes
4061 -- exiting from the loop when it is appropriate to insert the freeze
4062 -- node before the current node P.
4064 -- Also checks some special exceptions to the freezing rules. These
4065 -- cases result in a direct return, bypassing the freeze action.
4068 loop
4071 -- If we don't have a parent, then we are not in a well-formed tree.
4072 -- This is an unusual case, but there are some legitimate situations
4073 -- in which this occurs, notably when the expressions in the range of
4074 -- a type declaration are resolved. We simply ignore the freeze
4075 -- request in this case. Is this right ???
4081 -- See if we have got to an appropriate point in the tree
4085 -- A special test for the exception of (RM 13.14(8)) for the case
4086 -- of per-object expressions (RM 3.8(18)) occurring in component
4087 -- definition or a discrete subtype definition. Note that we test
4088 -- for a component declaration which includes both cases we are
4089 -- interested in, and furthermore the tree does not have explicit
4090 -- nodes for either of these two constructs.
4094 -- The case we want to test for here is an identifier that is
4095 -- a per-object expression, this is either a discriminant that
4096 -- appears in a context other than the component declaration
4097 -- or it is a reference to the type of the enclosing construct.
4099 -- For either of these cases, we skip the freezing
4101 if not In_Spec_Expression
4104 then
4105 -- We recognize the discriminant case by just looking for
4106 -- a reference to a discriminant. It can only be one for
4107 -- the enclosing construct. Skip freezing in this case.
4112 -- For the case of a reference to the enclosing record,
4113 -- (or task or protected type), we look for a type that
4114 -- matches the current scope.
4121 -- If we have an enumeration literal that appears as the choice in
4122 -- the aggregate of an enumeration representation clause, then
4123 -- freezing does not occur (RM 13.14(10)).
4127 -- The case we are looking for is an enumeration literal
4131 then
4132 -- If enumeration literal appears directly as the choice,
4133 -- do not freeze (this is the normal non-overloaded case)
4137 then
4140 -- If enumeration literal appears as the name of function
4141 -- which is the choice, then also do not freeze. This
4142 -- happens in the overloaded literal case, where the
4143 -- enumeration literal is temporarily changed to a function
4144 -- call for overloading analysis purposes.
4147 and then
4149 and then
4151 then
4156 -- Normally if the parent is a handled sequence of statements,
4157 -- then the current node must be a statement, and that is an
4158 -- appropriate place to insert a freeze node.
4162 -- An exception occurs when the sequence of statements is for
4163 -- an expander generated body that did not do the usual freeze
4164 -- all operation. In this case we usually want to freeze
4165 -- outside this body, not inside it, and we skip past the
4166 -- subprogram body that we are inside.
4170 -- However, we *do* want to freeze at this point if we have
4171 -- an entity to freeze, and that entity is declared *inside*
4172 -- the body of the expander generated procedure. This case
4173 -- is recognized by the scope of the type, which is either
4174 -- the spec for some enclosing body, or (in the case of
4175 -- init_procs, for which there are no separate specs) the
4176 -- current scope.
4178 declare
4182 begin
4187 or else
4189 then
4195 then
4201 -- If not that exception to the exception, then this is
4202 -- where we delay the freeze till outside the body.
4207 -- Here if normal case where we are in handled statement
4208 -- sequence and want to do the insertion right there.
4210 else
4214 -- If parent is a body or a spec or a block, then the current node
4215 -- is a statement or declaration and we can insert the freeze node
4216 -- before it.
4218 when N_Package_Specification |
4219 N_Package_Body |
4220 N_Subprogram_Body |
4221 N_Task_Body |
4222 N_Protected_Body |
4223 N_Entry_Body |
4226 -- The expander is allowed to define types in any statements list,
4227 -- so any of the following parent nodes also mark a freezing point
4228 -- if the actual node is in a list of statements or declarations.
4230 when N_Exception_Handler |
4231 N_If_Statement |
4232 N_Elsif_Part |
4233 N_Case_Statement_Alternative |
4234 N_Compilation_Unit_Aux |
4235 N_Selective_Accept |
4236 N_Accept_Alternative |
4237 N_Delay_Alternative |
4238 N_Conditional_Entry_Call |
4239 N_Entry_Call_Alternative |
4240 N_Triggering_Alternative |
4241 N_Abortable_Part |
4242 N_Freeze_Entity =>
4246 -- Note: The N_Loop_Statement is a special case. A type that
4247 -- appears in the source can never be frozen in a loop (this
4248 -- occurs only because of a loop expanded by the expander), so we
4249 -- keep on going. Otherwise we terminate the search. Same is true
4250 -- of any entity which comes from source. (if they have predefined
4251 -- type, that type does not appear to come from source, but the
4252 -- entity should not be frozen here).
4258 -- For all other cases, keep looking at parents
4264 -- We fall through the case if we did not yet find the proper
4265 -- place in the free for inserting the freeze node, so climb!
4270 -- If the expression appears in a record or an initialization procedure,
4271 -- the freeze nodes are collected and attached to the current scope, to
4272 -- be inserted and analyzed on exit from the scope, to insure that
4273 -- generated entities appear in the correct scope. If the expression is
4274 -- a default for a discriminant specification, the scope is still void.
4275 -- The expression can also appear in the discriminant part of a private
4276 -- or concurrent type.
4278 -- If the expression appears in a constrained subcomponent of an
4279 -- enclosing record declaration, the freeze nodes must be attached to
4280 -- the outer record type so they can eventually be placed in the
4281 -- enclosing declaration list.
4283 -- The other case requiring this special handling is if we are in a
4284 -- default expression, since in that case we are about to freeze a
4285 -- static type, and the freeze scope needs to be the outer scope, not
4286 -- the scope of the subprogram with the default parameter.
4288 -- For default expressions and other spec expressions in generic units,
4289 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
4290 -- placing them at the proper place, after the generic unit.
4293 or else Freeze_Outside
4298 then
4299 declare
4304 begin
4317 -- The current scope may be that of a constrained component of
4318 -- an enclosing record declaration, which is above the current
4319 -- scope in the scope stack.
4328 Freeze_Nodes;
4329 else
4339 -- Now we have the right place to do the freezing. First, a special
4340 -- adjustment, if we are in spec-expression analysis mode, these freeze
4341 -- actions must not be thrown away (normally all inserted actions are
4342 -- thrown away in this mode. However, the freeze actions are from static
4343 -- expressions and one of the important reasons we are doing this
4344 -- special analysis is to get these freeze actions. Therefore we turn
4345 -- off the In_Spec_Expression mode to propagate these freeze actions.
4346 -- This also means they get properly analyzed and expanded.
4350 -- Freeze the designated type of an allocator (RM 13.14(13))
4356 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
4357 -- the enumeration representation clause exception in the loop above.
4363 -- Freeze name if one is present (RM 13.14(11))
4369 -- Restore In_Spec_Expression flag
4374 -----------------------------
4375 -- Freeze_Fixed_Point_Type --
4376 -----------------------------
4378 -- Certain fixed-point types and subtypes, including implicit base types
4379 -- and declared first subtypes, have not yet set up a range. This is
4380 -- because the range cannot be set until the Small and Size values are
4381 -- known, and these are not known till the type is frozen.
4383 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
4384 -- whose bounds are unanalyzed real literals. This routine will recognize
4385 -- this case, and transform this range node into a properly typed range
4386 -- with properly analyzed and resolved values.
4404 -- Returns size of type with given bounds. Also leaves these
4405 -- bounds set as the current bounds of the Typ.
4407 -----------
4408 -- Fsize --
4409 -----------
4412 begin
4418 -- Start of processing for Freeze_Fixed_Point_Type
4420 begin
4421 -- If Esize of a subtype has not previously been set, set it now
4428 else
4433 -- Immediate return if the range is already analyzed. This means that
4434 -- the range is already set, and does not need to be computed by this
4435 -- routine.
4441 -- Immediate return if either of the bounds raises Constraint_Error
4445 then
4452 -- Ordinary fixed-point case
4456 -- For the ordinary fixed-point case, we are allowed to fudge the
4457 -- end-points up or down by small. Generally we prefer to fudge up,
4458 -- i.e. widen the bounds for non-model numbers so that the end points
4459 -- are included. However there are cases in which this cannot be
4460 -- done, and indeed cases in which we may need to narrow the bounds.
4461 -- The following circuit makes the decision.
4463 -- Note: our terminology here is that Incl_EP means that the bounds
4464 -- are widened by Small if necessary to include the end points, and
4465 -- Excl_EP means that the bounds are narrowed by Small to exclude the
4466 -- end-points if this reduces the size.
4468 -- Note that in the Incl case, all we care about is including the
4469 -- end-points. In the Excl case, we want to narrow the bounds as
4470 -- much as permitted by the RM, to give the smallest possible size.
4487 begin
4488 -- First step. Base types are required to be symmetrical. Right
4489 -- now, the base type range is a copy of the first subtype range.
4490 -- This will be corrected before we are done, but right away we
4491 -- need to deal with the case where both bounds are non-negative.
4492 -- In this case, we set the low bound to the negative of the high
4493 -- bound, to make sure that the size is computed to include the
4494 -- required sign. Note that we do not need to worry about the
4495 -- case of both bounds negative, because the sign will be dealt
4496 -- with anyway. Furthermore we can't just go making such a bound
4497 -- symmetrical, since in a twos-complement system, there is an
4498 -- extra negative value which could not be accommodated on the
4499 -- positive side.
4504 then
4509 -- Compute the fudged bounds. If the number is a model number,
4510 -- then we do nothing to include it, but we are allowed to backoff
4511 -- to the next adjacent model number when we exclude it. If it is
4512 -- not a model number then we straddle the two values with the
4513 -- model numbers on either side.
4519 else
4523 -- The low value excluding the end point is Small greater, but
4524 -- we do not do this exclusion if the low value is positive,
4525 -- since it can't help the size and could actually hurt by
4526 -- crossing the high bound.
4531 -- If the value went from negative to zero, then we have the
4532 -- case where Loval_Incl_EP is the model number just below
4533 -- zero, so we want to stick to the negative value for the
4534 -- base type to maintain the condition that the size will
4535 -- include signed values.
4539 then
4543 else
4547 -- Similar processing for upper bound and high value
4553 else
4559 else
4563 -- One further adjustment is needed. In the case of subtypes, we
4564 -- cannot go outside the range of the base type, or we get
4565 -- peculiarities, and the base type range is already set. This
4566 -- only applies to the Incl values, since clearly the Excl values
4567 -- are already as restricted as they are allowed to be.
4574 -- Get size including and excluding end points
4579 -- No need to exclude end-points if it does not reduce size
4589 -- Now we set the actual size to be used. We want to use the
4590 -- bounds fudged up to include the end-points but only if this
4591 -- can be done without violating a specifically given size
4592 -- size clause or causing an unacceptable increase in size.
4594 -- Case of size clause given
4598 -- Use the inclusive size only if it is consistent with
4599 -- the explicitly specified size.
4606 -- If the inclusive size is too large, we try excluding
4607 -- the end-points (will be caught later if does not work).
4609 else
4615 -- Case of size clause not given
4617 else
4618 -- If we have a base type whose corresponding first subtype
4619 -- has an explicit size that is large enough to include our
4620 -- end-points, then do so. There is no point in working hard
4621 -- to get a base type whose size is smaller than the specified
4622 -- size of the first subtype.
4628 then
4633 -- If excluding the end-points makes the size smaller and
4634 -- results in a size of 8,16,32,64, then we take the smaller
4635 -- size. For the 64 case, this is compulsory. For the other
4636 -- cases, it seems reasonable. We like to include end points
4637 -- if we can, but not at the expense of moving to the next
4638 -- natural boundary of size.
4641 and then
4646 then
4651 -- Otherwise we can definitely include the end points
4653 else
4659 -- One pathological case: normally we never fudge a low bound
4660 -- down, since it would seem to increase the size (if it has
4661 -- any effect), but for ranges containing single value, or no
4662 -- values, the high bound can be small too large. Consider:
4664 -- type t is delta 2.0**(-14)
4665 -- range 131072.0 .. 0;
4667 -- That lower bound is *just* outside the range of 32 bits, and
4668 -- does need fudging down in this case. Note that the bounds
4669 -- will always have crossed here, since the high bound will be
4670 -- fudged down if necessary, as in the case of:
4672 -- type t is delta 2.0**(-14)
4673 -- range 131072.0 .. 131072.0;
4675 -- So we detect the situation by looking for crossed bounds,
4676 -- and if the bounds are crossed, and the low bound is greater
4677 -- than zero, we will always back it off by small, since this
4678 -- is completely harmless.
4685 -- And of course, we need to do exactly the same parallel
4686 -- fudge for flat ranges in the negative region.
4699 -- For the decimal case, none of this fudging is required, since there
4700 -- are no end-point problems in the decimal case (the end-points are
4701 -- always included).
4703 else
4707 -- At this stage, the actual size has been calculated and the proper
4708 -- required bounds are stored in the low and high bounds.
4712 Error_Msg_N
4714 Typ);
4718 -- Check size against explicit given size
4724 Error_Msg_NE
4728 else
4732 -- Increase size to next natural boundary if no size clause given
4734 else
4741 else
4749 -- If we have a base type, then expand the bounds so that they extend to
4750 -- the full width of the allocated size in bits, to avoid junk range
4751 -- checks on intermediate computations.
4758 -- Final step is to reanalyze the bounds using the proper type
4759 -- and set the Corresponding_Integer_Value fields of the literals.
4765 -- Resolve with universal fixed if the base type, and the base type if
4766 -- it is a subtype. Note we can't resolve the base type with itself,
4767 -- that would be a reference before definition.
4771 else
4775 -- Set corresponding integer value for bound
4777 Set_Corresponding_Integer_Value
4780 -- Similar processing for high bound
4788 else
4792 Set_Corresponding_Integer_Value
4795 -- Set type of range to correspond to bounds
4799 -- Set Esize to calculated size if not set already
4805 -- Set RM_Size if not already set. If already set, check value
4807 declare
4810 begin
4815 Error_Msg_NE
4820 else
4826 ------------------
4827 -- Freeze_Itype --
4828 ------------------
4833 begin
4842 --------------------------
4843 -- Freeze_Static_Object --
4844 --------------------------
4849 -- Exception raised if the type of a static object cannot be made
4850 -- static. This happens if the type depends on non-global objects.
4853 -- Called to ensure that an expression used as part of a type definition
4854 -- is statically allocatable, which means that the expression type is
4855 -- statically allocatable, and the expression is either static, or a
4856 -- reference to a library level constant.
4859 -- Called to mark a type as static, checking that it is possible
4860 -- to set the type as static. If it is not possible, then the
4861 -- exception Cannot_Be_Static is raised.
4863 -----------------------------
4864 -- Ensure_Expression_Is_SA --
4865 -----------------------------
4870 begin
4882 then
4890 -----------------------
4891 -- Ensure_Type_Is_SA --
4892 -----------------------
4898 begin
4899 -- If type is library level, we are all set
4905 -- We are also OK if the type already marked as statically allocated,
4906 -- which means we processed it before.
4912 -- Mark type as statically allocated
4916 -- Check that it is safe to statically allocate this type
4934 declare
4938 begin
4951 else
4960 then
4979 else
4984 -- Start of processing for Freeze_Static_Object
4986 begin
4989 exception
4992 -- If the object that cannot be static is imported or exported,
4993 -- then we give an error message saying that this object cannot
4994 -- be imported or exported.
4997 Error_Msg_N
5000 -- Otherwise must be exported, something is wrong if compiler
5001 -- is marking something as statically allocated which cannot be).
5004 Error_Msg_N
5009 -----------------------
5010 -- Freeze_Subprogram --
5011 -----------------------
5017 begin
5018 -- Subprogram may not have an address clause unless it is imported
5022 Error_Msg_N
5029 -- Reset the Pure indication on an imported subprogram unless an
5030 -- explicit Pure_Function pragma was present. We do this because
5031 -- otherwise it is an insidious error to call a non-pure function from
5032 -- pure unit and have calls mysteriously optimized away. What happens
5033 -- here is that the Import can bypass the normal check to ensure that
5034 -- pure units call only pure subprograms.
5039 then
5043 -- For non-foreign convention subprograms, this is where we create
5044 -- the extra formals (for accessibility level and constrained bit
5045 -- information). We delay this till the freeze point precisely so
5046 -- that we know the convention!
5052 -- If this is convention Ada and a Valued_Procedure, that's odd
5057 and then Warn_On_Export_Import
5058 then
5059 Error_Msg_N
5064 -- Case of foreign convention
5066 else
5069 -- For foreign conventions, warn about return of an
5070 -- unconstrained array.
5072 -- Note: we *do* allow a return by descriptor for the VMS case,
5073 -- though here there is probably more to be done ???
5078 -- If no return type, probably some other error, e.g. a
5079 -- missing full declaration, so ignore.
5084 -- If the return type is generic, we have emitted a warning
5085 -- earlier on, and there is nothing else to check here. Specific
5086 -- instantiations may lead to erroneous behavior.
5094 and then Warn_On_Export_Import
5095 then
5096 Error_Msg_N
5103 -- If any of the formals for an exported foreign convention
5104 -- subprogram have defaults, then emit an appropriate warning since
5105 -- this is odd (default cannot be used from non-Ada code)
5110 if Warn_On_Export_Import
5112 then
5113 Error_Msg_N
5123 -- For VMS, descriptor mechanisms for parameters are allowed only
5124 -- for imported/exported subprograms. Moreover, the NCA descriptor
5125 -- is not allowed for parameters of exported subprograms.
5132 Error_Msg_N
5134 Error_Msg_N
5145 Error_Msg_N
5147 Error_Msg_N
5156 -- Pragma Inline_Always is disallowed for dispatching subprograms
5157 -- because the address of such subprograms is saved in the dispatch
5158 -- table to support dispatching calls, and dispatching calls cannot
5159 -- be inlined. This is consistent with the restriction against using
5160 -- 'Access or 'Address on an Inline_Always subprogram.
5164 then
5165 Error_Msg_N
5169 -- Because of the implicit representation of inherited predefined
5170 -- operators in the front-end, the overriding status of the operation
5171 -- may be affected when a full view of a type is analyzed, and this is
5172 -- not captured by the analysis of the corresponding type declaration.
5173 -- Therefore the correctness of a not-overriding indicator must be
5174 -- rechecked when the subprogram is frozen.
5178 then
5183 ----------------------
5184 -- Is_Fully_Defined --
5185 ----------------------
5188 begin
5197 then
5198 -- Verify that the record type has no components with private types
5199 -- without completion.
5201 declare
5204 begin
5217 else
5223 ---------------------------------
5224 -- Process_Default_Expressions --
5225 ---------------------------------
5227 procedure Process_Default_Expressions
5230 is
5237 begin
5240 -- A subprogram instance and its associated anonymous subprogram share
5241 -- their signature. The default expression functions are defined in the
5242 -- wrapper packages for the anonymous subprogram, and should not be
5243 -- generated again for the instance.
5248 then
5256 -- We work with a copy of the default expression because we
5257 -- do not want to disturb the original, since this would mess
5258 -- up the conformance checking.
5262 -- The analysis of the expression may generate insert actions,
5263 -- which of course must not be executed. We wrap those actions
5264 -- in a procedure that is not called, and later on eliminated.
5265 -- The following cases have no side-effects, and are analyzed
5266 -- directly.
5277 and then
5279 then
5281 -- If there is no default function, we must still do a full
5282 -- analyze call on the default value, to ensure that all error
5283 -- checks are performed, e.g. those associated with static
5284 -- evaluation. Note: this branch will always be taken if the
5285 -- analyzer is turned off (but we still need the error checks).
5287 -- Note: the setting of parent here is to meet the requirement
5288 -- that we can only analyze the expression while attached to
5289 -- the tree. Really the requirement is that the parent chain
5290 -- be set, we don't actually need to be in the tree.
5295 -- Default expressions are resolved with their own type if the
5296 -- context is generic, to avoid anomalies with private types.
5300 else
5304 -- If that resolved expression will raise constraint error,
5305 -- then flag the default value as raising constraint error.
5306 -- This allows a proper error message on the calls.
5312 -- If the default is a parameterless call, we use the name of
5313 -- the called function directly, and there is no body to build.
5317 then
5320 -- Else construct and analyze the body of a wrapper procedure
5321 -- that contains an object declaration to hold the expression.
5322 -- Given that this is done only to complete the analysis, it
5323 -- simpler to build a procedure than a function which might
5324 -- involve secondary stack expansion.
5326 else
5327 Dnam :=
5330 Dbody :=
5332 Specification =>
5338 Defining_Identifier =>
5341 Object_Definition =>
5345 Handled_Statement_Sequence =>
5362 ----------------------------------------
5363 -- Set_Component_Alignment_If_Not_Set --
5364 ----------------------------------------
5367 begin
5368 -- Ignore if not base type, subtypes don't need anything
5374 -- Do not override existing representation
5385 else
5386 Set_Component_Alignment
5392 ------------------
5393 -- Undelay_Type --
5394 ------------------
5397 begin
5401 -- Since we don't want T to have a Freeze_Node, we don't want its
5402 -- Full_View or Corresponding_Record_Type to have one either.
5404 -- ??? Fundamentally, this whole handling is a kludge. What we really
5405 -- want is to be sure that for an Itype that's part of record R and is a
5406 -- subtype of type T, that it's frozen after the later of the freeze
5407 -- points of R and T. We have no way of doing that directly, so what we
5408 -- do is force most such Itypes to be frozen as part of freezing R via
5409 -- this procedure and only delay the ones that need to be delayed
5410 -- (mostly the designated types of access types that are defined as part
5411 -- of the record).
5417 then
5425 then
5430 ------------------
5431 -- Warn_Overlay --
5432 ------------------
5434 procedure Warn_Overlay
5438 is
5440 -- The object to which the address clause applies
5446 begin
5447 -- No warning if address clause overlay warnings are off
5453 -- No warning if there is an explicit initialization
5461 -- We only give the warning for non-imported entities of a type for
5462 -- which a non-null base init proc is defined (or for access types which
5463 -- have implicit null initialization).
5469 then
5472 then
5477 then
5484 then
5491 -- A function call (most likely to To_Address) is probably not an
5492 -- overlay, so skip warning. Ditto if the function call was inlined
5493 -- and transformed into an entity.
5501 -- If a pragma Import follows, we assume that it is for the current
5502 -- target of the address clause, and skip the warning.
5507 then
5513 Error_Msg_N
5515 Nam);
5516 else
5517 Error_Msg_N
5519 Nam);
5522 -- Add friendly warning if initialization comes from a packed array
5523 -- component.
5526 declare
5529 begin
5535 then
5539 then
5540 Error_Msg_NE
5545 else
5552 Error_Msg_N
5555 Nam);