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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) 1992-2009, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
17 -- --
18 -- You should have received a copy of the GNU General Public License along --
19 -- with this program; see file COPYING3. If not see --
20 -- <http://www.gnu.org/licenses/>. --
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 ------------------------------------------------------------------------------
69 -----------------------
70 -- Local Subprograms --
71 -----------------------
74 -- Typ is a type that is being frozen. If no size clause is given,
75 -- but a default Esize has been computed, then this default Esize is
76 -- adjusted up if necessary to be consistent with a given alignment,
77 -- but never to a value greater than Long_Long_Integer'Size. This
78 -- is used for all discrete types and for fixed-point types.
80 procedure Build_And_Analyze_Renamed_Body
84 -- Build body for a renaming declaration, insert in tree and analyze
87 -- Apply legality checks to address clauses for object declarations,
88 -- at the point the object is frozen.
91 -- E is a base type. If E is tagged or has a component that is aliased
92 -- or tagged or contains something this is aliased or tagged, set
93 -- Strict_Alignment.
97 -- If E is a fixed-point or discrete type, then all the necessary work
98 -- to freeze it is completed except for possible setting of the flag
99 -- Is_Unsigned_Type, which is done by this procedure. The call has no
100 -- effect if the entity E is not a discrete or fixed-point type.
102 procedure Freeze_And_Append
106 -- Freezes Ent using Freeze_Entity, and appends the resulting list of
107 -- nodes to Result, modifying Result from No_List if necessary.
110 -- Freeze enumeration type. The Esize field is set as processing
111 -- proceeds (i.e. set by default when the type is declared and then
112 -- adjusted by rep clauses. What this procedure does is to make sure
113 -- that if a foreign convention is specified, and no specific size
114 -- is given, then the size must be at least Integer'Size.
117 -- If an object is frozen which has Is_Statically_Allocated set, then
118 -- all referenced types must also be marked with this flag. This routine
119 -- is in charge of meeting this requirement for the object entity E.
122 -- Perform freezing actions for a subprogram (create extra formals,
123 -- and set proper default mechanism values). Note that this routine
124 -- is not called for internal subprograms, for which neither of these
125 -- actions is needed (or desirable, we do not want for example to have
126 -- these extra formals present in initialization procedures, where they
127 -- would serve no purpose). In this call E is either a subprogram or
128 -- a subprogram type (i.e. an access to a subprogram).
131 -- True if T is not private and has no private components, or has a full
132 -- view. Used to determine whether the designated type of an access type
133 -- should be frozen when the access type is frozen. This is done when an
134 -- allocator is frozen, or an expression that may involve attributes of
135 -- the designated type. Otherwise freezing the access type does not freeze
136 -- the designated type.
139 -- For a tagged type, generate implicit references to its primitive
140 -- operations, for source navigation.
142 procedure Process_Default_Expressions
145 -- This procedure is called for each subprogram to complete processing
146 -- of default expressions at the point where all types are known to be
147 -- frozen. The expressions must be analyzed in full, to make sure that
148 -- all error processing is done (they have only been pre-analyzed). If
149 -- the expression is not an entity or literal, its analysis may generate
150 -- code which must not be executed. In that case we build a function
151 -- body to hold that code. This wrapper function serves no other purpose
152 -- (it used to be called to evaluate the default, but now the default is
153 -- inlined at each point of call).
156 -- Typ is a record or array type that is being frozen. This routine
157 -- sets the default component alignment from the scope stack values
158 -- if the alignment is otherwise not specified.
161 -- As each entity is frozen, this routine is called to deal with the
162 -- setting of Debug_Info_Needed for the entity. This flag is set if
163 -- the entity comes from source, or if we are in Debug_Generated_Code
164 -- mode or if the -gnatdV debug flag is set. However, it never sets
165 -- the flag if Debug_Info_Off is set. This procedure also ensures that
166 -- subsidiary entities have the flag set as required.
169 -- T is a type of a component that we know to be an Itype.
170 -- We don't want this to have a Freeze_Node, so ensure it doesn't.
171 -- Do the same for any Full_View or Corresponding_Record_Type.
173 procedure Warn_Overlay
177 -- Expr is the expression for an address clause for entity Nam whose type
178 -- is Typ. If Typ has a default initialization, and there is no explicit
179 -- initialization in the source declaration, check whether the address
180 -- clause might cause overlaying of an entity, and emit a warning on the
181 -- side effect that the initialization will cause.
183 -------------------------------
184 -- Adjust_Esize_For_Alignment --
185 -------------------------------
190 begin
196 then
202 ------------------------------------
203 -- Build_And_Analyze_Renamed_Body --
204 ------------------------------------
206 procedure Build_And_Analyze_Renamed_Body
210 is
212 begin
219 ------------------------
220 -- Build_Renamed_Body --
221 ------------------------
223 function Build_Renamed_Body
226 is
228 -- We use for the source location of the renamed body, the location
229 -- of the spec entity. It might seem more natural to use the location
230 -- of the renaming declaration itself, but that would be wrong, since
231 -- then the body we create would look as though it was created far
232 -- too late, and this could cause problems with elaboration order
233 -- analysis, particularly in connection with instantiations.
248 -- If the renamed entity is a primitive operation given in prefix form,
249 -- the prefix is the target object and it has to be added as the first
250 -- actual in the generated call.
252 begin
253 -- Determine the entity being renamed, which is the target of the call
254 -- statement. If the name is an explicit dereference, this is a renaming
255 -- of a subprogram type rather than a subprogram. The name itself is
256 -- fully analyzed.
267 else
274 else
280 -- If the renamed entity is a predefined operator, retain full name
281 -- to ensure its visibility.
285 then
287 else
291 else
294 and then
297 then
299 -- Retrieve the target object, to be added as a first actual
300 -- in the call.
305 else
309 -- The original name may have been overloaded, but
310 -- is fully resolved now.
315 -- For simple renamings, subsequent calls can be expanded directly as
316 -- called to the renamed entity. The body must be generated in any case
317 -- for calls they may appear elsewhere.
322 then
326 -- The body generated for this renaming is an internal artifact, and
327 -- does not constitute a freeze point for the called entity.
334 declare
338 begin
340 -- The controlling formal may be an access parameter, or the
341 -- actual may be an access value, so adjust accordingly.
345 then
346 Actuals := New_List
351 then
352 Actuals := New_List
356 else
364 else
375 -- If the renamed entity is an entry, inherit its profile. For other
376 -- renamings as bodies, both profiles must be subtype conformant, so it
377 -- is not necessary to replace the profile given in the declaration.
378 -- However, default values that are aggregates are rewritten when
379 -- partially analyzed, so we recover the original aggregate to insure
380 -- that subsequent conformity checking works. Similarly, if the default
381 -- expression was constant-folded, recover the original expression.
393 N_Access_Definition
394 then
402 then
413 -- If the renamed entity is a function, the generated body contains a
414 -- return statement. Otherwise, build a procedure call. If the entity is
415 -- an entry, subsequent analysis of the call will transform it into the
416 -- proper entry or protected operation call. If the renamed entity is
417 -- a character literal, return it directly.
423 then
424 Call_Node :=
426 Expression =>
432 Call_Node :=
437 Call_Node :=
441 else
442 Call_Node :=
448 -- Create entities for subprogram body and formals
462 Body_Node :=
466 Handled_Statement_Sequence =>
476 -- Link the body to the entity whose declaration it completes. If
477 -- the body is analyzed when the renamed entity is frozen, it may
478 -- be necessary to restore the proper scope (see package Exp_Ch13).
482 then
484 else
491 --------------------------
492 -- Check_Address_Clause --
493 --------------------------
501 begin
505 -- If we have no initialization of any kind, then we don't need to
506 -- place any restrictions on the address clause, because the object
507 -- will be elaborated after the address clause is evaluated. This
508 -- happens if the declaration has no initial expression, or the type
509 -- has no implicit initialization, or the object is imported.
511 -- The same holds for all initialized scalar types and all access
512 -- types. Packed bit arrays of size up to 64 are represented using a
513 -- modular type with an initialization (to zero) and can be processed
514 -- like other initialized scalar types.
516 -- If the type is controlled, code to attach the object to a
517 -- finalization chain is generated at the point of declaration,
518 -- and therefore the elaboration of the object cannot be delayed:
519 -- the address expression must be a constant.
523 and then
527 or else
531 or else
534 or else
536 and then
538 then
541 -- Otherwise, we require the address clause to be constant because
542 -- the call to the initialization procedure (or the attach code) has
543 -- to happen at the point of the declaration.
545 else
552 then
558 -----------------------------
559 -- Check_Compile_Time_Size --
560 -----------------------------
565 -- Sets the compile time known size (32 bits or less) in the Esize
566 -- field, of T checking for a size clause that was given which attempts
567 -- to give a smaller size.
570 -- Recursive function that does all the work
573 -- If T is a constrained subtype, its size is not known if any of its
574 -- discriminant constraints is not static and it is not a null record.
575 -- The test is conservative and doesn't check that the components are
576 -- in fact constrained by non-static discriminant values. Could be made
577 -- more precise ???
579 --------------------
580 -- Set_Small_Size --
581 --------------------
584 begin
591 Error_Msg_NE
599 -- Set sizes if not set already
601 else
612 ----------------
613 -- Size_Known --
614 ----------------
623 begin
627 -- Always True for scalar types. This is true even for generic formal
628 -- scalar types. We used to return False in the latter case, but the
629 -- size is known at compile time, even in the template, we just do
630 -- not know the exact size but that's not the point of this routine.
634 then
637 -- Array types
641 -- String literals always have known size, and we can set it
648 -- Unconstrained types never have known at compile time size
653 -- Don't do any recursion on type with error posted, since we may
654 -- have a malformed type that leads us into a loop.
659 -- Otherwise if component size unknown, then array size unknown
665 -- Check for all indexes static, and also compute possible size
666 -- (in case it is less than 32 and may be packable).
668 declare
672 begin
681 else
689 then
692 else
697 else
709 -- Access types always have known at compile time sizes
714 -- For non-generic private types, go to underlying type if present
719 then
720 -- Don't do any recursion on type with error posted, since we may
721 -- have a malformed type that leads us into a loop.
725 else
729 -- Record types
733 -- A class-wide type is never considered to have a known size
738 -- A subtype of a variant record must not have non-static
739 -- discriminanted components.
743 then
746 -- Don't do any recursion on type with error posted, since we may
747 -- have a malformed type that leads us into a loop.
753 -- Now look at the components of the record
755 declare
756 -- The following two variables are used to keep track of the
757 -- size of packed records if we can tell the size of the packed
758 -- record in the front end. Packed_Size_Known is True if so far
759 -- we can figure out the size. It is initialized to True for a
760 -- packed record, unless the record has discriminants. The
761 -- reason we eliminate the discriminated case is that we don't
762 -- know the way the back end lays out discriminated packed
763 -- records. If Packed_Size_Known is True, then Packed_Size is
764 -- the size in bits so far.
772 begin
773 -- Test for variant part present
779 N_Record_Definition
783 then
784 -- If variant part is present, and type is unconstrained,
785 -- then we must have defaulted discriminants, or a size
786 -- clause must be present for the type, or else the size
787 -- is definitely not known at compile time.
790 and then
791 No (Discriminant_Default_Value
794 then
799 -- Loop through components
805 -- We do not know the packed size if there is a component
806 -- clause present (we possibly could, but this would only
807 -- help in the case of a record with partial rep clauses.
808 -- That's because in the case of full rep clauses, the
809 -- size gets figured out anyway by a different circuit).
815 -- We need to identify a component that is an array where
816 -- the index type is an enumeration type with non-standard
817 -- representation, and some bound of the type depends on a
818 -- discriminant.
820 -- This is because gigi computes the size by doing a
821 -- substitution of the appropriate discriminant value in
822 -- the size expression for the base type, and gigi is not
823 -- clever enough to evaluate the resulting expression (which
824 -- involves a call to rep_to_pos) at compile time.
826 -- It would be nice if gigi would either recognize that
827 -- this expression can be computed at compile time, or
828 -- alternatively figured out the size from the subtype
829 -- directly, where all the information is at hand ???
833 then
834 declare
842 begin
849 then
855 then
860 then
870 -- Clearly size of record is not known if the size of one of
871 -- the components is not known.
877 -- Accumulate packed size if possible
881 -- We can only deal with elementary types, since for
882 -- non-elementary components, alignment enters into the
883 -- picture, and we don't know enough to handle proper
884 -- alignment in this context. Packed arrays count as
885 -- elementary if the representation is a modular type.
890 and then Is_Modular_Integer_Type
892 then
893 -- If RM_Size is known and static, then we can
894 -- keep accumulating the packed size.
898 -- A little glitch, to be removed sometime ???
899 -- gigi does not understand zero sizes yet.
904 -- Normal case where we can keep accumulating the
905 -- packed array size.
907 else
911 -- If we have a field whose RM_Size is not known then
912 -- we can't figure out the packed size here.
914 else
918 -- If we have a non-elementary type we can't figure out
919 -- the packed array size (alignment issues).
921 else
936 -- All other cases, size not known at compile time
938 else
943 -------------------------------------
944 -- Static_Discriminated_Components --
945 -------------------------------------
947 function Static_Discriminated_Components
949 is
952 begin
956 then
970 -- Start of processing for Check_Compile_Time_Size
972 begin
976 -----------------------------
977 -- Check_Debug_Info_Needed --
978 -----------------------------
981 begin
986 or else Debug_Generated_Code
987 or else Debug_Flag_VV
989 then
994 ----------------------------
995 -- Check_Strict_Alignment --
996 ----------------------------
1001 begin
1020 then
1030 -------------------------
1031 -- Check_Unsigned_Type --
1032 -------------------------
1039 begin
1044 -- Do not attempt to analyze case where range was in error
1050 -- The situation that is non trivial is something like
1052 -- subtype x1 is integer range -10 .. +10;
1053 -- subtype x2 is x1 range 0 .. V1;
1054 -- subtype x3 is x2 range V2 .. V3;
1055 -- subtype x4 is x3 range V4 .. V5;
1057 -- where Vn are variables. Here the base type is signed, but we still
1058 -- know that x4 is unsigned because of the lower bound of x2.
1060 -- The only way to deal with this is to look up the ancestor chain
1063 loop
1078 else
1081 -- If no ancestor had a static lower bound, go to base type
1085 -- Note: the reason we still check for a compile time known
1086 -- value for the base type is that at least in the case of
1087 -- generic formals, we can have bounds that fail this test,
1088 -- and there may be other cases in error situations.
1100 then
1110 -----------------------------
1111 -- Expand_Atomic_Aggregate --
1112 -----------------------------
1119 begin
1124 then
1125 Temp :=
1129 New_N :=
1139 -- To prevent the temporary from being constant-folded (which would
1140 -- lead to the same piecemeal assignment on the original target)
1141 -- indicate to the back-end that the temporary is a variable with
1142 -- real storage. See description of this flag in Einfo, and the notes
1143 -- on N_Assignment_Statement and N_Object_Declaration in Sinfo.
1149 ----------------
1150 -- Freeze_All --
1151 ----------------
1153 -- Note: the easy coding for this procedure would be to just build a
1154 -- single list of freeze nodes and then insert them and analyze them
1155 -- all at once. This won't work, because the analysis of earlier freeze
1156 -- nodes may recursively freeze types which would otherwise appear later
1157 -- on in the freeze list. So we must analyze and expand the freeze nodes
1158 -- as they are generated.
1166 -- This is the internal recursive routine that does freezing of entities
1167 -- (but NOT the analysis of default expressions, which should not be
1168 -- recursive, we don't want to analyze those till we are sure that ALL
1169 -- the types are frozen).
1171 --------------------
1172 -- Freeze_All_Ent --
1173 --------------------
1175 procedure Freeze_All_Ent
1178 is
1184 -- If freeze nodes are present, insert and analyze, and reset cursor
1185 -- for next insertion.
1187 -------------------
1188 -- Process_Flist --
1189 -------------------
1192 begin
1199 else
1205 -- Start or processing for Freeze_All_Ent
1207 begin
1211 -- If the entity is an inner package which is not a package
1212 -- renaming, then its entities must be frozen at this point. Note
1213 -- that such entities do NOT get frozen at the end of the nested
1214 -- package itself (only library packages freeze).
1216 -- Same is true for task declarations, where anonymous records
1217 -- created for entry parameters must be frozen.
1223 then
1233 and then
1235 or else
1237 then
1240 End_Scope;
1242 -- For a derived tagged type, we must ensure that all the
1243 -- primitive operations of the parent have been frozen, so that
1244 -- their addresses will be in the parent's dispatch table at the
1245 -- point it is inherited.
1251 then
1252 declare
1259 begin
1267 then
1269 Process_Flist;
1279 Process_Flist;
1282 -- If an incomplete type is still not frozen, this may be a
1283 -- premature freezing because of a body declaration that follows.
1284 -- Indicate where the freezing took place.
1286 -- If the freezing is caused by the end of the current declarative
1287 -- part, it is a Taft Amendment type, and there is no error.
1291 then
1292 declare
1295 begin
1302 and then
1304 then
1306 Error_Msg_NE
1317 -- Start of processing for Freeze_All
1319 begin
1322 -- Now that all types are frozen, we can deal with default expressions
1323 -- that require us to build a default expression functions. This is the
1324 -- point at which such functions are constructed (after all types that
1325 -- might be used in such expressions have been frozen).
1327 -- We also add finalization chains to access types whose designated
1328 -- types are controlled. This is normally done when freezing the type,
1329 -- but this misses recursive type definitions where the later members
1330 -- of the recursion introduce controlled components.
1332 -- Loop through entities
1350 and then
1352 = N_Subprogram_Renaming_Declaration
1353 then
1354 Build_And_Analyze_Renamed_Body
1360 and then
1362 or else
1364 then
1365 declare
1367 begin
1374 then
1387 then
1395 -----------------------
1396 -- Freeze_And_Append --
1397 -----------------------
1399 procedure Freeze_And_Append
1403 is
1405 begin
1409 else
1415 -------------------
1416 -- Freeze_Before --
1417 -------------------
1421 begin
1427 -------------------
1428 -- Freeze_Entity --
1429 -------------------
1441 -- This flag gets set to true for a variable with default initialization
1444 -- Check that an Access or Unchecked_Access attribute with a prefix
1445 -- which is the current instance type can only be applied when the type
1446 -- is limited.
1449 -- If Loc is a freeze_entity that appears after the last declaration
1450 -- in the scope, inhibit error messages on late completion.
1453 -- Freeze each component, handle some representation clauses, and freeze
1454 -- primitive operations if this is a tagged type.
1456 ----------------------------
1457 -- After_Last_Declaration --
1458 ----------------------------
1462 begin
1468 else
1471 else
1476 ----------------------------
1477 -- Check_Current_Instance --
1478 ----------------------------
1488 -- Process routine to apply check to given node
1490 -------------
1491 -- Process --
1492 -------------
1495 begin
1499 or else
1504 then
1505 Error_Msg_N
1508 else
1518 -- Start of processing for Check_Current_Instance
1520 begin
1521 -- In Ada95, the (imprecise) rule is that the current instance of a
1522 -- limited type is aliased. In Ada2005, limitedness must be explicit:
1523 -- either a tagged type, or a limited record.
1526 and then
1529 then
1534 then
1537 else
1542 ------------------------
1543 -- Freeze_Record_Type --
1544 ------------------------
1556 -- Set True if we find at least one component with no component
1557 -- clause (used to warn about useless Pack pragmas).
1560 -- Set True if we find at least one component with a component
1561 -- clause (used to warn about useless Bit_Order pragmas).
1564 -- If N is an allocator, possibly wrapped in one or more level of
1565 -- qualified expression(s), return the inner allocator node, else
1566 -- return Empty.
1569 -- If the component subtype is an access to a constrained subtype of
1570 -- an already frozen type, make the subtype frozen as well. It might
1571 -- otherwise be frozen in the wrong scope, and a freeze node on
1572 -- subtype has no effect. Similarly, if the component subtype is a
1573 -- regular (not protected) access to subprogram, set the anonymous
1574 -- subprogram type to frozen as well, to prevent an out-of-scope
1575 -- freeze node at some eventual point of call. Protected operations
1576 -- are handled elsewhere.
1578 ---------------------
1579 -- Check_Allocator --
1580 ---------------------
1584 begin
1586 loop
1591 else
1597 -----------------
1598 -- Check_Itype --
1599 -----------------
1604 begin
1607 then
1610 -- In addition, add an Itype_Reference to ensure that the
1611 -- access subtype is elaborated early enough. This cannot be
1612 -- done if the subtype may depend on discriminants.
1617 then
1623 else
1630 then
1635 -- Start of processing for Freeze_Record_Type
1637 begin
1638 -- If this is a subtype of a controlled type, declared without a
1639 -- constraint, the _controller may not appear in the component list
1640 -- if the parent was not frozen at the point of subtype declaration.
1641 -- Inherit the _controller component now.
1645 then
1648 then
1651 -- If this is an internal type without a declaration, as for
1652 -- record component, the base type may not yet be frozen, and its
1653 -- controller has not been created. Add an explicit freeze node
1654 -- for the itype, so it will be frozen after the base type. This
1655 -- freeze node is used to communicate with the expander, in order
1656 -- to create the controller for the enclosing record, and it is
1657 -- deleted afterwards (see exp_ch3). It must not be created when
1658 -- expansion is off, because it might appear in the wrong context
1659 -- for the back end.
1663 and then
1665 N_Component_Declaration
1666 and then Expander_Active
1667 then
1672 -- Freeze components and embedded subtypes
1678 -- First handle the (real) component case
1682 then
1683 declare
1686 begin
1687 -- Freezing a record type freezes the type of each of its
1688 -- components. However, if the type of the component is
1689 -- part of this record, we do not want or need a separate
1690 -- Freeze_Node. Note that Is_Itype is wrong because that's
1691 -- also set in private type cases. We also can't check for
1692 -- the Scope being exactly Rec because of private types and
1693 -- record extensions.
1698 then
1704 -- Check for error of component clause given for variable
1705 -- sized type. We have to delay this test till this point,
1706 -- since the component type has to be frozen for us to know
1707 -- if it is variable length. We omit this test in a generic
1708 -- context, it will be applied at instantiation time.
1716 elsif not
1717 Size_Known_At_Compile_Time
1719 then
1720 Error_Msg_N
1725 else
1729 -- Case of component requires byte alignment
1733 -- Set the enclosing record to also require byte align
1737 -- Check for component clause that is inconsistent with
1738 -- the required byte boundary alignment.
1743 then
1744 Error_Msg_N
1750 -- If component clause is present, then deal with the non-
1751 -- default bit order case for Ada 95 mode. The required
1752 -- processing for Ada 2005 mode is handled separately after
1753 -- processing all components.
1755 -- We only do this processing for the base type, and in
1756 -- fact that's important, since otherwise if there are
1757 -- record subtypes, we could reverse the bits once for
1758 -- each subtype, which would be incorrect.
1764 then
1765 declare
1778 begin
1779 -- Cases where field goes over storage unit boundary
1783 -- Allow multi-byte field but generate warning
1787 then
1788 Error_Msg_N
1793 Error_Msg_N
1796 else
1797 Error_Msg_N
1802 -- Do not allow non-contiguous field
1804 else
1805 Error_Msg_N
1808 Error_Msg_N
1811 Error_Msg_N
1816 -- Case where field fits in one storage unit
1818 else
1819 -- Give warning if suspicious component clause
1822 and then Warn_On_Reverse_Bit_Order
1823 then
1824 Error_Msg_N
1827 Error_Msg_Uint_1 :=
1829 System_Storage_Unit;
1830 Error_Msg_N
1835 -- Here is where we fix up the Component_Bit_Offset
1836 -- value to account for the reverse bit order.
1837 -- Some examples of what needs to be done are:
1839 -- First_Bit .. Last_Bit Component_Bit_Offset
1840 -- old new old new
1842 -- 0 .. 0 7 .. 7 0 7
1843 -- 0 .. 1 6 .. 7 0 6
1844 -- 0 .. 2 5 .. 7 0 5
1845 -- 0 .. 7 0 .. 7 0 4
1847 -- 1 .. 1 6 .. 6 1 6
1848 -- 1 .. 4 3 .. 6 1 3
1849 -- 4 .. 7 0 .. 3 4 0
1851 -- The general rule is that the first bit is
1852 -- is obtained by subtracting the old ending bit
1853 -- from storage_unit - 1.
1855 Set_Component_Bit_Offset
1861 Set_Normalized_First_Bit
1864 System_Storage_Unit);
1871 -- If the component is an Itype with Delayed_Freeze and is either
1872 -- a record or array subtype and its base type has not yet been
1873 -- frozen, we must remove this from the entity list of this
1874 -- record and put it on the entity list of the scope of its base
1875 -- type. Note that we know that this is not the type of a
1876 -- component since we cleared Has_Delayed_Freeze for it in the
1877 -- previous loop. Thus this must be the Designated_Type of an
1878 -- access type, which is the type of a component.
1886 then
1887 declare
1891 begin
1892 -- We have a pretty bad kludge here. Suppose Rec is subtype
1893 -- being defined in a subprogram that's created as part of
1894 -- the freezing of Rec'Base. In that case, we know that
1895 -- Comp'Base must have already been frozen by the time we
1896 -- get to elaborate this because Gigi doesn't elaborate any
1897 -- bodies until it has elaborated all of the declarative
1898 -- part. But Is_Frozen will not be set at this point because
1899 -- we are processing code in lexical order.
1901 -- We detect this case by going up the Scope chain of Rec
1902 -- and seeing if we have a subprogram scope before reaching
1903 -- the top of the scope chain or that of Comp'Base. If we
1904 -- do, then mark that Comp'Base will actually be frozen. If
1905 -- so, we merely undelay it.
1921 else
1924 else
1928 -- Insert in entity list of scope of base type (which
1929 -- must be an enclosing scope, because still unfrozen).
1935 -- If the component is an access type with an allocator as default
1936 -- value, the designated type will be frozen by the corresponding
1937 -- expression in init_proc. In order to place the freeze node for
1938 -- the designated type before that for the current record type,
1939 -- freeze it now.
1941 -- Same process if the component is an array of access types,
1942 -- initialized with an aggregate. If the designated type is
1943 -- private, it cannot contain allocators, and it is premature
1944 -- to freeze the type, so we check for this as well.
1949 then
1950 declare
1954 begin
1957 -- If component is pointer to a classwide type, freeze
1958 -- the specific type in the expression being allocated.
1959 -- The expression may be a subtype indication, in which
1960 -- case freeze the subtype mark.
1962 if Is_Class_Wide_Type
1964 then
1966 Freeze_And_Append
1968 elsif
1970 then
1971 Freeze_And_Append
1979 else
1980 Freeze_And_Append
1988 then
1997 and then Is_Fully_Defined
1999 then
2000 Freeze_And_Append
2001 (Designated_Type
2009 -- Deal with pragma Bit_Order
2013 ADC :=
2015 Error_Msg_N
2017 Error_Msg_N
2020 -- Here is where we do Ada 2005 processing for bit order (the Ada
2021 -- 95 case was already taken care of above).
2028 -- Set OK_To_Reorder_Components depending on debug flags
2032 then
2034 or else
2036 then
2041 -- Check for useless pragma Pack when all components placed. We only
2042 -- do this check for record types, not subtypes, since a subtype may
2043 -- have all its components placed, and it still makes perfectly good
2044 -- sense to pack other subtypes or the parent type. We do not give
2045 -- this warning if Optimize_Alignment is set to Space, since the
2046 -- pragma Pack does have an effect in this case (it always resets
2047 -- the alignment to one).
2051 and then not Unplaced_Component
2053 then
2054 -- Reset packed status. Probably not necessary, but we do it so
2055 -- that there is no chance of the back end doing something strange
2056 -- with this redundant indication of packing.
2060 -- Give warning if redundant constructs warnings on
2063 Error_Msg_N
2069 -- If this is the record corresponding to a remote type, freeze the
2070 -- remote type here since that is what we are semantically freezing.
2071 -- This prevents the freeze node for that type in an inner scope.
2073 -- Also, Check for controlled components and unchecked unions.
2074 -- Finally, enforce the restriction that access attributes with a
2075 -- current instance prefix can only apply to limited types.
2079 Freeze_And_Append
2089 and then Present
2091 and then Has_Controlled_Component
2093 then
2104 -- Scan component declaration for likely misuses of current
2105 -- instance, either in a constraint or a default expression.
2116 -- For first subtypes, check if there are any fixed-point fields with
2117 -- component clauses, where we must check the size. This is not done
2118 -- till the freeze point, since for fixed-point types, we do not know
2119 -- the size until the type is frozen. Similar processing applies to
2120 -- bit packed arrays.
2128 or else
2130 then
2131 Check_Size
2135 Junk);
2142 -- Generate warning for applying C or C++ convention to a record
2143 -- with discriminants. This is suppressed for the unchecked union
2144 -- case, since the whole point in this case is interface C. We also
2145 -- do not generate this within instantiations, since we will have
2146 -- generated a message on the template.
2151 or else
2154 and then not In_Instance
2157 then
2158 declare
2162 begin
2167 Error_Msg_N
2169 else
2170 Error_Msg_N
2174 Error_Msg_NE
2181 -- Start of processing for Freeze_Entity
2183 begin
2184 -- We are going to test for various reasons why this entity need not be
2185 -- frozen here, but in the case of an Itype that's defined within a
2186 -- record, that test actually applies to the record.
2192 then
2196 -- Do not freeze if already frozen since we only need one freeze node
2201 -- It is improper to freeze an external entity within a generic because
2202 -- its freeze node will appear in a non-valid context. The entity will
2203 -- be frozen in the proper scope after the current generic is analyzed.
2208 -- Do not freeze a global entity within an inner scope created during
2209 -- expansion. A call to subprogram E within some internal procedure
2210 -- (a stream attribute for example) might require freezing E, but the
2211 -- freeze node must appear in the same declarative part as E itself.
2212 -- The two-pass elaboration mechanism in gigi guarantees that E will
2213 -- be frozen before the inner call is elaborated. We exclude constants
2214 -- from this test, because deferred constants may be frozen early, and
2215 -- must be diagnosed (e.g. in the case of a deferred constant being used
2216 -- in a default expression). If the enclosing subprogram comes from
2217 -- source, or is a generic instance, then the freeze point is the one
2218 -- mandated by the language, and we freeze the entity. A subprogram that
2219 -- is a child unit body that acts as a spec does not have a spec that
2220 -- comes from source, but can only come from source.
2225 then
2226 declare
2229 begin
2235 then
2237 else
2246 -- Similarly, an inlined instance body may make reference to global
2247 -- entities, but these references cannot be the proper freezing point
2248 -- for them, and in the absence of inlining freezing will take place in
2249 -- their own scope. Normally instance bodies are analyzed after the
2250 -- enclosing compilation, and everything has been frozen at the proper
2251 -- place, but with front-end inlining an instance body is compiled
2252 -- before the end of the enclosing scope, and as a result out-of-order
2253 -- freezing must be prevented.
2255 elsif Front_End_Inlining
2256 and then In_Instance_Body
2258 then
2259 declare
2262 begin
2266 else
2277 -- Here to freeze the entity
2282 -- Case of entity being frozen is other than a type
2286 -- If entity is exported or imported and does not have an external
2287 -- name, now is the time to provide the appropriate default name.
2288 -- Skip this if the entity is stubbed, since we don't need a name
2289 -- for any stubbed routine.
2294 then
2295 Set_Encoded_Interface_Name
2298 -- Special processing for atomic objects appearing in object decls
2303 then
2304 declare
2307 begin
2308 -- If expression is an aggregate, assign to a temporary to
2309 -- ensure that the actual assignment is done atomically rather
2310 -- than component-wise (the assignment to the temp may be done
2311 -- component-wise, but that is harmless).
2316 -- If the expression is a reference to a record or array object
2317 -- entity, then reset Is_True_Constant to False so that the
2318 -- compiler will not optimize away the intermediate object,
2319 -- which we need in this case for the same reason (to ensure
2320 -- that the actual assignment is atomic, rather than
2321 -- component-wise).
2325 or else
2327 then
2333 -- For a subprogram, freeze all parameter types and also the return
2334 -- type (RM 13.14(14)). However skip this for internal subprograms.
2335 -- This is also the point where any extra formal parameters are
2336 -- created since we now know whether the subprogram will use
2337 -- a foreign convention.
2341 declare
2346 begin
2347 -- Loop through formals
2359 then
2360 -- If the type of a formal is incomplete, subprogram
2361 -- is being frozen prematurely. Within an instance
2362 -- (but not within a wrapper package) this is an
2363 -- an artifact of our need to regard the end of an
2364 -- instantiation as a freeze point. Otherwise it is
2365 -- a definite error.
2367 -- and then not Is_Wrapper_Package (Current_Scope) ???
2373 elsif not After_Last_Declaration
2374 and then not Freezing_Library_Level_Tagged_Type
2375 then
2377 Error_Msg
2379 Loc);
2383 -- Check suspicious parameter for C function. These tests
2384 -- apply only to exported/imported subprograms.
2386 if Warn_On_Export_Import
2389 or else
2396 then
2399 -- Check suspicious use of fat C pointer
2403 then
2404 Error_Msg_N
2408 -- Check suspicious return of boolean
2414 then
2415 Error_Msg_N
2419 -- Check suspicious tagged type
2423 and then
2424 Is_Tagged_Type
2427 then
2428 Error_Msg_N
2432 -- Check wrong convention subprogram pointer
2436 then
2437 Error_Msg_N
2441 Error_Msg_NE
2449 -- Check for unconstrained array in exported foreign
2450 -- convention case.
2456 and then Warn_On_Export_Import
2457 then
2460 -- If this is an inherited operation, place the
2461 -- warning on the derived type declaration, rather
2462 -- than on the original subprogram.
2465 N_Full_Type_Declaration
2466 then
2470 Error_Msg_NE
2473 else
2477 Error_Msg_NE
2480 Error_Msg_NE
2491 -- If the formal is an anonymous_access_to_subprogram
2492 -- freeze the subprogram type as well, to prevent
2493 -- scope anomalies in gigi, because there is no other
2494 -- clear point at which it could be frozen.
2498 then
2506 -- Case of function: similar checks on return type
2510 -- Freeze return type
2515 -- Check suspicious return type for C function
2517 if Warn_On_Export_Import
2519 or else
2522 then
2523 -- Check suspicious return of fat C pointer
2529 then
2530 Error_Msg_N
2534 -- Check suspicious return of boolean
2541 then
2542 Error_Msg_N
2546 -- Check suspicious return tagged type
2550 and then
2551 Is_Tagged_Type
2556 then
2557 Error_Msg_N
2561 -- Check return of wrong convention subprogram pointer
2567 then
2568 Error_Msg_N
2572 Error_Msg_NE
2582 and then Warn_On_Export_Import
2585 then
2586 Error_Msg_N
2594 -- Must freeze its parent first if it is a derived subprogram
2600 -- We don't freeze internal subprograms, because we don't normally
2601 -- want addition of extra formals or mechanism setting to happen
2602 -- for those. However we do pass through predefined dispatching
2603 -- cases, since extra formals may be needed in some cases, such as
2604 -- for the stream 'Input function (build-in-place formals).
2608 then
2612 -- Here for other than a subprogram or type
2614 else
2615 -- For a generic package, freeze types within, so that proper
2616 -- cross-reference information is generated for tagged types.
2617 -- This is the only freeze processing needed for generic packages.
2620 declare
2623 begin
2634 -- If entity has a type, and it is not a generic unit, then
2635 -- freeze it first (RM 13.14(10)).
2639 then
2643 -- Special processing for objects created by object declaration
2647 -- For object created by object declaration, perform required
2648 -- categorization (preelaborate and pure) checks. Defer these
2649 -- checks to freeze time since pragma Import inhibits default
2650 -- initialization and thus pragma Import affects these checks.
2654 -- If there is an address clause, check that it is valid
2658 -- If the object needs any kind of default initialization, an
2659 -- error must be issued if No_Default_Initialization applies.
2660 -- The check doesn't apply to imported objects, which are not
2661 -- ever default initialized, and is why the check is deferred
2662 -- until freezing, at which point we know if Import applies.
2663 -- Deferred constants are also exempted from this test because
2664 -- their completion is explicit, or through an import pragma.
2668 then
2674 and then
2679 or else
2682 then
2684 Check_Restriction
2688 -- Check that a Thread_Local_Storage variable does not have
2689 -- default initialization, and any explicit initialization must
2690 -- either be the null constant or a static constant.
2693 declare
2695 begin
2696 if Has_Default_Initialization
2697 or else
2699 and then
2701 or else not
2703 or else
2705 then
2706 Error_Msg_NE
2709 Error_Msg_NE
2716 -- For imported objects, set Is_Public unless there is also an
2717 -- address clause, which means that there is no external symbol
2718 -- needed for the Import (Is_Public may still be set for other
2719 -- unrelated reasons). Note that we delayed this processing
2720 -- till freeze time so that we can be sure not to set the flag
2721 -- if there is an address clause. If there is such a clause,
2722 -- then the only purpose of the Import pragma is to suppress
2723 -- implicit initialization.
2727 then
2731 -- For convention C objects of an enumeration type, warn if
2732 -- the size is not integer size and no explicit size given.
2733 -- Skip warning for Boolean, and Character, assume programmer
2734 -- expects 8-bit sizes for these cases.
2737 or else
2744 then
2746 Error_Msg_N
2748 E);
2753 -- Check that a constant which has a pragma Volatile[_Components]
2754 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
2756 -- Note: Atomic[_Components] also sets Volatile[_Components]
2761 then
2762 -- Make sure we actually have a pragma, and have not merely
2763 -- inherited the indication from elsewhere (e.g. an address
2764 -- clause, which is not good enough in RM terms!)
2767 or else
2769 then
2770 Error_Msg_N
2775 or else
2777 then
2778 Error_Msg_N
2784 -- Static objects require special handling
2788 then
2792 -- Remaining step is to layout objects
2795 or else
2797 or else
2799 or else
2801 then
2806 -- Case of a type or subtype being frozen
2808 else
2809 -- We used to check here that a full type must have preelaborable
2810 -- initialization if it completes a private type specified with
2811 -- pragma Preelaborable_Intialization, but that missed cases where
2812 -- the types occur within a generic package, since the freezing
2813 -- that occurs within a containing scope generally skips traversal
2814 -- of a generic unit's declarations (those will be frozen within
2815 -- instances). This check was moved to Analyze_Package_Specification.
2817 -- The type may be defined in a generic unit. This can occur when
2818 -- freezing a generic function that returns the type (which is
2819 -- defined in a parent unit). It is clearly meaningless to freeze
2820 -- this type. However, if it is a subtype, its size may be determi-
2821 -- nable and used in subsequent checks, so might as well try to
2822 -- compute it.
2826 then
2831 -- Deal with special cases of freezing for subtype
2835 -- Before we do anything else, a specialized test for the case of
2836 -- a size given for an array where the array needs to be packed,
2837 -- but was not so the size cannot be honored. This would of course
2838 -- be caught by the backend, and indeed we don't catch all cases.
2839 -- The point is that we can give a better error message in those
2840 -- cases that we do catch with the circuitry here. Also if pragma
2841 -- Implicit_Packing is set, this is where the packing occurs.
2843 -- The reason we do this so early is that the processing in the
2844 -- automatic packing case affects the layout of the base type, so
2845 -- it must be done before we freeze the base type.
2848 declare
2852 begin
2853 -- Check enabling conditions. These are straightforward
2854 -- except for the test for a limited composite type. This
2855 -- eliminates the rare case of a array of limited components
2856 -- where there are issues of whether or not we can go ahead
2857 -- and pack the array (since we can't freely pack and unpack
2858 -- arrays if they are limited).
2860 -- Note that we check the root type explicitly because the
2861 -- whole point is we are doing this test before we have had
2862 -- a chance to freeze the base type (and it is that freeze
2863 -- action that causes stuff to be inherited).
2875 then
2882 then
2883 declare
2893 -- What we are looking for here is the situation where
2894 -- the RM_Size given would be exactly right if there
2895 -- was a pragma Pack (resulting in the component size
2896 -- being the same as the RM_Size). Furthermore, the
2897 -- component type size must be an odd size (not a
2898 -- multiple of storage unit)
2900 begin
2903 then
2904 -- For implicit packing mode, just set the
2905 -- component size silently
2913 -- Otherwise give an error message
2915 else
2916 Error_Msg_NE
2918 Error_Msg_N
2929 -- If ancestor subtype present, freeze that first. Note that this
2930 -- will also get the base type frozen.
2937 -- Otherwise freeze the base type of the entity before freezing
2938 -- the entity itself (RM 13.14(15)).
2944 -- For a derived type, freeze its parent type first (RM 13.14(15))
2951 -- For array type, freeze index types and component type first
2952 -- before freezing the array (RM 13.14(15)).
2955 declare
2959 -- Set true if any of the index types is an enumeration type
2960 -- with a non-standard representation.
2962 begin
2971 then
2978 -- Processing that is done only for base types
2982 -- Propagate flags for component type
2986 then
2994 -- If packing was requested or if the component size was set
2995 -- explicitly, then see if bit packing is required. This
2996 -- processing is only done for base types, since all the
2997 -- representation aspects involved are type-related. This
2998 -- is not just an optimization, if we start processing the
2999 -- subtypes, they interfere with the settings on the base
3000 -- type (this is because Is_Packed has a slightly different
3001 -- meaning before and after freezing).
3003 declare
3007 begin
3011 then
3020 else
3023 -- We can set the component size if it is less than
3024 -- 16, rounding it up to the next storage unit size.
3030 else
3034 -- Set component size up to match alignment if it
3035 -- would otherwise be less than the alignment. This
3036 -- deals with cases of types whose alignment exceeds
3037 -- their size (padded types).
3040 declare
3042 begin
3050 -- Case of component size that may result in packing
3053 declare
3059 Get_Attribute_Definition_Clause
3061 begin
3062 -- Warn if we have pack and component size so that
3063 -- the pack is ignored.
3065 -- Note: here we must check for the presence of a
3066 -- component size before checking for a Pack pragma
3067 -- to deal with the case where the array type is a
3068 -- derived type whose parent is currently private.
3072 then
3074 Error_Msg_NE
3077 Error_Msg_N
3079 Pack_Pragma);
3082 -- Set component size if not already set by a
3083 -- component size clause.
3089 -- Check for base type of 8, 16, 32 bits, where an
3090 -- unsigned subtype has a length one less than the
3091 -- base type (e.g. Natural subtype of Integer).
3093 -- In such cases, if a component size was not set
3094 -- explicitly, then generate a warning.
3098 and then
3101 then
3105 Error_Msg_N
3108 Error_Msg_N
3114 -- Actual packing is not needed for 8, 16, 32, 64.
3115 -- Also not needed for 24 if alignment is 1.
3122 then
3123 -- Here the array was requested to be packed,
3124 -- but the packing request had no effect, so
3125 -- Is_Packed is reset.
3127 -- Note: semantically this means that we lose
3128 -- track of the fact that a derived type
3129 -- inherited a pragma Pack that was non-
3130 -- effective, but that seems fine.
3132 -- We regard a Pack pragma as a request to set
3133 -- a representation characteristic, and this
3134 -- request may be ignored.
3138 -- In all other cases, packing is indeed needed
3140 else
3149 -- Processing that is done only for subtypes
3151 else
3152 -- Acquire alignment from base type
3160 -- For bit-packed arrays, check the size
3164 then
3165 declare
3171 begin
3172 -- It is not clear if it is possible to have no size
3173 -- clause at this stage, but it is not worth worrying
3174 -- about. Post error on the entity name in the size
3175 -- clause if present, else on the type entity itself.
3179 else
3185 -- If any of the index types was an enumeration type with
3186 -- a non-standard rep clause, then we indicate that the
3187 -- array type is always packed (even if it is not bit packed).
3196 -- If the array is packed, we must create the packed array
3197 -- type to be used to actually implement the type. This is
3198 -- only needed for real array types (not for string literal
3199 -- types, since they are present only for the front end).
3203 then
3207 -- Size information of packed array type is copied to the
3208 -- array type, since this is really the representation. But
3209 -- do not override explicit existing size values. If the
3210 -- ancestor subtype is constrained the packed_array_type
3211 -- will be inherited from it, but the size may have been
3212 -- provided already, and must not be overridden either.
3215 and then
3218 then
3228 -- For non-packed arrays set the alignment of the array to the
3229 -- alignment of the component type if it is unknown. Skip this
3230 -- in atomic case (atomic arrays may need larger alignments).
3239 then
3244 -- For a class-wide type, the corresponding specific type is
3245 -- frozen as well (RM 13.14(15))
3250 -- If the base type of the class-wide type is still incomplete,
3251 -- the class-wide remains unfrozen as well. This is legal when
3252 -- E is the formal of a primitive operation of some other type
3253 -- which is being frozen.
3260 -- If the Class_Wide_Type is an Itype (when type is the anonymous
3261 -- parent of a derived type) and it is a library-level entity,
3262 -- generate an itype reference for it. Otherwise, its first
3263 -- explicit reference may be in an inner scope, which will be
3264 -- rejected by the back-end.
3268 then
3269 declare
3272 begin
3276 else
3282 -- The equivalent type associated with a class-wide subtype needs
3283 -- to be frozen to ensure that its layout is done. Class-wide
3284 -- subtypes are currently only frozen on targets requiring
3285 -- front-end layout (see New_Class_Wide_Subtype and
3286 -- Make_CW_Equivalent_Type in exp_util.adb).
3290 then
3294 -- For a record (sub)type, freeze all the component types (RM
3295 -- 13.14(15). We test for E_Record_(sub)Type here, rather than using
3296 -- Is_Record_Type, because we don't want to attempt the freeze for
3297 -- the case of a private type with record extension (we will do that
3298 -- later when the full type is frozen).
3302 then
3305 -- For a concurrent type, freeze corresponding record type. This
3306 -- does not correspond to any specific rule in the RM, but the
3307 -- record type is essentially part of the concurrent type.
3308 -- Freeze as well all local entities. This includes record types
3309 -- created for entry parameter blocks, and whatever local entities
3310 -- may appear in the private part.
3314 Freeze_And_Append
3327 then
3337 -- Private types are required to point to the same freeze node as
3338 -- their corresponding full views. The freeze node itself has to
3339 -- point to the partial view of the entity (because from the partial
3340 -- view, we can retrieve the full view, but not the reverse).
3341 -- However, in order to freeze correctly, we need to freeze the full
3342 -- view. If we are freezing at the end of a scope (or within the
3343 -- scope of the private type), the partial and full views will have
3344 -- been swapped, the full view appears first in the entity chain and
3345 -- the swapping mechanism ensures that the pointers are properly set
3346 -- (on scope exit).
3348 -- If we encounter the partial view before the full view (e.g. when
3349 -- freezing from another scope), we freeze the full view, and then
3350 -- set the pointers appropriately since we cannot rely on swapping to
3351 -- fix things up (subtypes in an outer scope might not get swapped).
3355 then
3356 -- The construction of the dispatch table associated with library
3357 -- level tagged types forces freezing of all the primitives of the
3358 -- type, which may cause premature freezing of the partial view.
3359 -- For example:
3361 -- package Pkg is
3362 -- type T is tagged private;
3363 -- type DT is new T with private;
3364 -- procedure Prim (X : in out T; Y : in out DT'class);
3365 -- private
3366 -- type T is tagged null record;
3367 -- Obj : T;
3368 -- type DT is new T with null record;
3369 -- end;
3371 -- In this case the type will be frozen later by the usual
3372 -- mechanism: an object declaration, an instantiation, or the
3373 -- end of a declarative part.
3377 then
3381 -- Case of full view present
3385 -- If full view has already been frozen, then no further
3386 -- processing is required
3394 -- Otherwise freeze full view and patch the pointers so that
3395 -- the freeze node will elaborate both views in the back-end.
3397 else
3398 declare
3401 begin
3404 then
3405 Freeze_And_Append
3418 else
3419 -- {Incomplete,Private}_Subtypes with Full_Views
3420 -- constrained by discriminants.
3431 -- AI-117 requires that the convention of a partial view be the
3432 -- same as the convention of the full view. Note that this is a
3433 -- recognized breach of privacy, but it's essential for logical
3434 -- consistency of representation, and the lack of a rule in
3435 -- RM95 was an oversight.
3442 -- Size information is copied from the full view to the
3443 -- incomplete or private view for consistency.
3445 -- We skip this is the full view is not a type. This is very
3446 -- strange of course, and can only happen as a result of
3447 -- certain illegalities, such as a premature attempt to derive
3448 -- from an incomplete type.
3457 -- Case of no full view present. If entity is derived or subtype,
3458 -- it is safe to freeze, correctness depends on the frozen status
3459 -- of parent. Otherwise it is either premature usage, or a Taft
3460 -- amendment type, so diagnosis is at the point of use and the
3461 -- type might be frozen later.
3465 then
3468 else
3473 -- For access subprogram, freeze types of all formals, the return
3474 -- type was already frozen, since it is the Etype of the function.
3475 -- Formal types can be tagged Taft amendment types, but otherwise
3476 -- they cannot be incomplete.
3485 then
3488 else
3489 Error_Msg_NE
3500 -- For access to a protected subprogram, freeze the equivalent type
3501 -- (however this is not set if we are not generating code or if this
3502 -- is an anonymous type used just for resolution).
3510 -- Generic types are never seen by the back-end, and are also not
3511 -- processed by the expander (since the expander is turned off for
3512 -- generic processing), so we never need freeze nodes for them.
3518 -- Some special processing for non-generic types to complete
3519 -- representation details not known till the freeze point.
3524 -- Some error checks required for ordinary fixed-point type. Defer
3525 -- these till the freeze-point since we need the small and range
3526 -- values. We only do these checks for base types
3530 then
3533 Error_Msg_N
3538 Error_Msg_N
3544 Error_Msg_N
3550 Error_Msg_N
3563 -- Check restriction for standard storage pool
3569 -- Deal with error message for pure access type. This is not an
3570 -- error in Ada 2005 if there is no pool (see AI-366).
3575 then
3579 Error_Msg_N
3583 Error_Msg_N
3586 else
3587 Error_Msg_N
3594 -- Case of composite types
3598 -- AI-117 requires that all new primitives of a tagged type must
3599 -- inherit the convention of the full view of the type. Inherited
3600 -- and overriding operations are defined to inherit the convention
3601 -- of their parent or overridden subprogram (also specified in
3602 -- AI-117), which will have occurred earlier (in Derive_Subprogram
3603 -- and New_Overloaded_Entity). Here we set the convention of
3604 -- primitives that are still convention Ada, which will ensure
3605 -- that any new primitives inherit the type's convention. Class-
3606 -- wide types can have a foreign convention inherited from their
3607 -- specific type, but are excluded from this since they don't have
3608 -- any associated primitives.
3613 then
3614 declare
3617 begin
3630 -- Generate references to primitive operations for a tagged type
3634 -- Now that all types from which E may depend are frozen, see if the
3635 -- size is known at compile time, if it must be unsigned, or if
3636 -- strict alignment is required
3645 -- Do not allow a size clause for a type which does not have a size
3646 -- that is known at compile time
3650 then
3651 -- Suppress this message if errors posted on E, even if we are
3652 -- in all errors mode, since this is often a junk message
3655 Error_Msg_N
3661 -- Remaining process is to set/verify the representation information,
3662 -- in particular the size and alignment values. This processing is
3663 -- not required for generic types, since generic types do not play
3664 -- any part in code generation, and so the size and alignment values
3665 -- for such types are irrelevant.
3670 -- Otherwise we call the layout procedure
3672 else
3676 -- End of freeze processing for type entities
3679 -- Here is where we logically freeze the current entity. If it has a
3680 -- freeze node, then this is the point at which the freeze node is
3681 -- linked into the result list.
3685 -- If a freeze node is already allocated, use it, otherwise allocate
3686 -- a new one. The preallocation happens in the case of anonymous base
3687 -- types, where we preallocate so that we can set First_Subtype_Link.
3688 -- Note that we reset the Sloc to the current freeze location.
3694 else
3706 else
3710 -- A final pass over record types with discriminants. If the type
3711 -- has an incomplete declaration, there may be constrained access
3712 -- subtypes declared elsewhere, which do not depend on the discrimi-
3713 -- nants of the type, and which are used as component types (i.e.
3714 -- the full view is a recursive type). The designated types of these
3715 -- subtypes can only be elaborated after the type itself, and they
3716 -- need an itype reference.
3720 then
3721 declare
3726 begin
3737 then
3749 -- When a type is frozen, the first subtype of the type is frozen as
3750 -- well (RM 13.14(15)). This has to be done after freezing the type,
3751 -- since obviously the first subtype depends on its own base type.
3756 -- If we just froze a tagged non-class wide record, then freeze the
3757 -- corresponding class-wide type. This must be done after the tagged
3758 -- type itself is frozen, because the class-wide type refers to the
3759 -- tagged type which generates the class.
3764 then
3771 -- Special handling for subprograms
3775 -- If subprogram has address clause then reset Is_Public flag, since
3776 -- we do not want the backend to generate external references.
3780 then
3783 -- If no address clause and not intrinsic, then for imported
3784 -- subprogram in main unit, generate descriptor if we are in
3785 -- Propagate_Exceptions mode.
3787 elsif Propagate_Exceptions
3791 then
3801 -----------------------------
3802 -- Freeze_Enumeration_Type --
3803 -----------------------------
3806 begin
3807 -- By default, if no size clause is present, an enumeration type with
3808 -- Convention C is assumed to interface to a C enum, and has integer
3809 -- size. This applies to types. For subtypes, verify that its base
3810 -- type has no size clause either.
3816 then
3819 else
3820 -- If the enumeration type interfaces to C, and it has a size clause
3821 -- that specifies less than int size, it warrants a warning. The
3822 -- user may intend the C type to be an enum or a char, so this is
3823 -- not by itself an error that the Ada compiler can detect, but it
3824 -- it is a worth a heads-up. For Boolean and Character types we
3825 -- assume that the programmer has the proper C type in mind.
3832 then
3833 Error_Msg_N
3841 -----------------------
3842 -- Freeze_Expression --
3843 -----------------------
3854 -- This flag is set true if the entity must be frozen outside the
3855 -- current subprogram. This happens in the case of expander generated
3856 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
3857 -- not freeze all entities like other bodies, but which nevertheless
3858 -- may reference entities that have to be frozen before the body and
3859 -- obviously cannot be frozen inside the body.
3862 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
3863 -- it is the handled statement sequence of an expander-generated
3864 -- subprogram (init proc, stream subprogram, or renaming as body).
3865 -- If so, this is not a freezing context.
3867 -----------------
3868 -- In_Exp_Body --
3869 -----------------
3875 begin
3878 else
3885 else
3895 N_Subprogram_Renaming_Declaration)
3896 then
3898 else
3904 -- Start of processing for Freeze_Expression
3906 begin
3907 -- Immediate return if freezing is inhibited. This flag is set by the
3908 -- analyzer to stop freezing on generated expressions that would cause
3909 -- freezing if they were in the source program, but which are not
3910 -- supposed to freeze, since they are created.
3916 -- If expression is non-static, then it does not freeze in a default
3917 -- expression, see section "Handling of Default Expressions" in the
3918 -- spec of package Sem for further details. Note that we have to
3919 -- make sure that we actually have a real expression (if we have
3920 -- a subtype indication, we can't test Is_Static_Expression!)
3922 if In_Spec_Exp
3925 then
3929 -- Freeze type of expression if not frozen already
3937 -- Base type may be an derived numeric type that is frozen at
3938 -- the point of declaration, but first_subtype is still unfrozen.
3945 -- For entity name, freeze entity if not frozen already. A special
3946 -- exception occurs for an identifier that did not come from source.
3947 -- We don't let such identifiers freeze a non-internal entity, i.e.
3948 -- an entity that did come from source, since such an identifier was
3949 -- generated by the expander, and cannot have any semantic effect on
3950 -- the freezing semantics. For example, this stops the parameter of
3951 -- an initialization procedure from freezing the variable.
3958 then
3960 else
3964 -- For an allocator freeze designated type if not frozen already
3966 -- For an aggregate whose component type is an access type, freeze the
3967 -- designated type now, so that its freeze does not appear within the
3968 -- loop that might be created in the expansion of the aggregate. If the
3969 -- designated type is a private type without full view, the expression
3970 -- cannot contain an allocator, so the type is not frozen.
3981 then
3985 when N_Selected_Component |
3986 N_Indexed_Component |
3987 N_Slice =>
4000 then
4004 -- All done if nothing needs freezing
4009 then
4013 -- Loop for looking at the right place to insert the freeze nodes
4014 -- exiting from the loop when it is appropriate to insert the freeze
4015 -- node before the current node P.
4017 -- Also checks some special exceptions to the freezing rules. These
4018 -- cases result in a direct return, bypassing the freeze action.
4021 loop
4024 -- If we don't have a parent, then we are not in a well-formed tree.
4025 -- This is an unusual case, but there are some legitimate situations
4026 -- in which this occurs, notably when the expressions in the range of
4027 -- a type declaration are resolved. We simply ignore the freeze
4028 -- request in this case. Is this right ???
4034 -- See if we have got to an appropriate point in the tree
4038 -- A special test for the exception of (RM 13.14(8)) for the case
4039 -- of per-object expressions (RM 3.8(18)) occurring in component
4040 -- definition or a discrete subtype definition. Note that we test
4041 -- for a component declaration which includes both cases we are
4042 -- interested in, and furthermore the tree does not have explicit
4043 -- nodes for either of these two constructs.
4047 -- The case we want to test for here is an identifier that is
4048 -- a per-object expression, this is either a discriminant that
4049 -- appears in a context other than the component declaration
4050 -- or it is a reference to the type of the enclosing construct.
4052 -- For either of these cases, we skip the freezing
4054 if not In_Spec_Expression
4057 then
4058 -- We recognize the discriminant case by just looking for
4059 -- a reference to a discriminant. It can only be one for
4060 -- the enclosing construct. Skip freezing in this case.
4065 -- For the case of a reference to the enclosing record,
4066 -- (or task or protected type), we look for a type that
4067 -- matches the current scope.
4074 -- If we have an enumeration literal that appears as the choice in
4075 -- the aggregate of an enumeration representation clause, then
4076 -- freezing does not occur (RM 13.14(10)).
4080 -- The case we are looking for is an enumeration literal
4084 then
4085 -- If enumeration literal appears directly as the choice,
4086 -- do not freeze (this is the normal non-overloaded case)
4090 then
4093 -- If enumeration literal appears as the name of function
4094 -- which is the choice, then also do not freeze. This
4095 -- happens in the overloaded literal case, where the
4096 -- enumeration literal is temporarily changed to a function
4097 -- call for overloading analysis purposes.
4100 and then
4102 and then
4104 then
4109 -- Normally if the parent is a handled sequence of statements,
4110 -- then the current node must be a statement, and that is an
4111 -- appropriate place to insert a freeze node.
4115 -- An exception occurs when the sequence of statements is for
4116 -- an expander generated body that did not do the usual freeze
4117 -- all operation. In this case we usually want to freeze
4118 -- outside this body, not inside it, and we skip past the
4119 -- subprogram body that we are inside.
4123 -- However, we *do* want to freeze at this point if we have
4124 -- an entity to freeze, and that entity is declared *inside*
4125 -- the body of the expander generated procedure. This case
4126 -- is recognized by the scope of the type, which is either
4127 -- the spec for some enclosing body, or (in the case of
4128 -- init_procs, for which there are no separate specs) the
4129 -- current scope.
4131 declare
4135 begin
4140 or else
4142 then
4148 then
4154 -- If not that exception to the exception, then this is
4155 -- where we delay the freeze till outside the body.
4160 -- Here if normal case where we are in handled statement
4161 -- sequence and want to do the insertion right there.
4163 else
4167 -- If parent is a body or a spec or a block, then the current node
4168 -- is a statement or declaration and we can insert the freeze node
4169 -- before it.
4171 when N_Package_Specification |
4172 N_Package_Body |
4173 N_Subprogram_Body |
4174 N_Task_Body |
4175 N_Protected_Body |
4176 N_Entry_Body |
4179 -- The expander is allowed to define types in any statements list,
4180 -- so any of the following parent nodes also mark a freezing point
4181 -- if the actual node is in a list of statements or declarations.
4183 when N_Exception_Handler |
4184 N_If_Statement |
4185 N_Elsif_Part |
4186 N_Case_Statement_Alternative |
4187 N_Compilation_Unit_Aux |
4188 N_Selective_Accept |
4189 N_Accept_Alternative |
4190 N_Delay_Alternative |
4191 N_Conditional_Entry_Call |
4192 N_Entry_Call_Alternative |
4193 N_Triggering_Alternative |
4194 N_Abortable_Part |
4195 N_Freeze_Entity =>
4199 -- Note: The N_Loop_Statement is a special case. A type that
4200 -- appears in the source can never be frozen in a loop (this
4201 -- occurs only because of a loop expanded by the expander), so we
4202 -- keep on going. Otherwise we terminate the search. Same is true
4203 -- of any entity which comes from source. (if they have predefined
4204 -- type, that type does not appear to come from source, but the
4205 -- entity should not be frozen here).
4211 -- For all other cases, keep looking at parents
4217 -- We fall through the case if we did not yet find the proper
4218 -- place in the free for inserting the freeze node, so climb!
4223 -- If the expression appears in a record or an initialization procedure,
4224 -- the freeze nodes are collected and attached to the current scope, to
4225 -- be inserted and analyzed on exit from the scope, to insure that
4226 -- generated entities appear in the correct scope. If the expression is
4227 -- a default for a discriminant specification, the scope is still void.
4228 -- The expression can also appear in the discriminant part of a private
4229 -- or concurrent type.
4231 -- If the expression appears in a constrained subcomponent of an
4232 -- enclosing record declaration, the freeze nodes must be attached to
4233 -- the outer record type so they can eventually be placed in the
4234 -- enclosing declaration list.
4236 -- The other case requiring this special handling is if we are in a
4237 -- default expression, since in that case we are about to freeze a
4238 -- static type, and the freeze scope needs to be the outer scope, not
4239 -- the scope of the subprogram with the default parameter.
4241 -- For default expressions and other spec expressions in generic units,
4242 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
4243 -- placing them at the proper place, after the generic unit.
4246 or else Freeze_Outside
4251 then
4252 declare
4257 begin
4270 -- The current scope may be that of a constrained component of
4271 -- an enclosing record declaration, which is above the current
4272 -- scope in the scope stack.
4281 Freeze_Nodes;
4282 else
4292 -- Now we have the right place to do the freezing. First, a special
4293 -- adjustment, if we are in spec-expression analysis mode, these freeze
4294 -- actions must not be thrown away (normally all inserted actions are
4295 -- thrown away in this mode. However, the freeze actions are from static
4296 -- expressions and one of the important reasons we are doing this
4297 -- special analysis is to get these freeze actions. Therefore we turn
4298 -- off the In_Spec_Expression mode to propagate these freeze actions.
4299 -- This also means they get properly analyzed and expanded.
4303 -- Freeze the designated type of an allocator (RM 13.14(13))
4309 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
4310 -- the enumeration representation clause exception in the loop above.
4316 -- Freeze name if one is present (RM 13.14(11))
4322 -- Restore In_Spec_Expression flag
4327 -----------------------------
4328 -- Freeze_Fixed_Point_Type --
4329 -----------------------------
4331 -- Certain fixed-point types and subtypes, including implicit base types
4332 -- and declared first subtypes, have not yet set up a range. This is
4333 -- because the range cannot be set until the Small and Size values are
4334 -- known, and these are not known till the type is frozen.
4336 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
4337 -- whose bounds are unanalyzed real literals. This routine will recognize
4338 -- this case, and transform this range node into a properly typed range
4339 -- with properly analyzed and resolved values.
4357 -- Returns size of type with given bounds. Also leaves these
4358 -- bounds set as the current bounds of the Typ.
4360 -----------
4361 -- Fsize --
4362 -----------
4365 begin
4371 -- Start of processing for Freeze_Fixed_Point_Type
4373 begin
4374 -- If Esize of a subtype has not previously been set, set it now
4381 else
4386 -- Immediate return if the range is already analyzed. This means that
4387 -- the range is already set, and does not need to be computed by this
4388 -- routine.
4394 -- Immediate return if either of the bounds raises Constraint_Error
4398 then
4405 -- Ordinary fixed-point case
4409 -- For the ordinary fixed-point case, we are allowed to fudge the
4410 -- end-points up or down by small. Generally we prefer to fudge up,
4411 -- i.e. widen the bounds for non-model numbers so that the end points
4412 -- are included. However there are cases in which this cannot be
4413 -- done, and indeed cases in which we may need to narrow the bounds.
4414 -- The following circuit makes the decision.
4416 -- Note: our terminology here is that Incl_EP means that the bounds
4417 -- are widened by Small if necessary to include the end points, and
4418 -- Excl_EP means that the bounds are narrowed by Small to exclude the
4419 -- end-points if this reduces the size.
4421 -- Note that in the Incl case, all we care about is including the
4422 -- end-points. In the Excl case, we want to narrow the bounds as
4423 -- much as permitted by the RM, to give the smallest possible size.
4440 begin
4441 -- First step. Base types are required to be symmetrical. Right
4442 -- now, the base type range is a copy of the first subtype range.
4443 -- This will be corrected before we are done, but right away we
4444 -- need to deal with the case where both bounds are non-negative.
4445 -- In this case, we set the low bound to the negative of the high
4446 -- bound, to make sure that the size is computed to include the
4447 -- required sign. Note that we do not need to worry about the
4448 -- case of both bounds negative, because the sign will be dealt
4449 -- with anyway. Furthermore we can't just go making such a bound
4450 -- symmetrical, since in a twos-complement system, there is an
4451 -- extra negative value which could not be accommodated on the
4452 -- positive side.
4457 then
4462 -- Compute the fudged bounds. If the number is a model number,
4463 -- then we do nothing to include it, but we are allowed to backoff
4464 -- to the next adjacent model number when we exclude it. If it is
4465 -- not a model number then we straddle the two values with the
4466 -- model numbers on either side.
4472 else
4476 -- The low value excluding the end point is Small greater, but
4477 -- we do not do this exclusion if the low value is positive,
4478 -- since it can't help the size and could actually hurt by
4479 -- crossing the high bound.
4484 -- If the value went from negative to zero, then we have the
4485 -- case where Loval_Incl_EP is the model number just below
4486 -- zero, so we want to stick to the negative value for the
4487 -- base type to maintain the condition that the size will
4488 -- include signed values.
4492 then
4496 else
4500 -- Similar processing for upper bound and high value
4506 else
4512 else
4516 -- One further adjustment is needed. In the case of subtypes, we
4517 -- cannot go outside the range of the base type, or we get
4518 -- peculiarities, and the base type range is already set. This
4519 -- only applies to the Incl values, since clearly the Excl values
4520 -- are already as restricted as they are allowed to be.
4527 -- Get size including and excluding end points
4532 -- No need to exclude end-points if it does not reduce size
4542 -- Now we set the actual size to be used. We want to use the
4543 -- bounds fudged up to include the end-points but only if this
4544 -- can be done without violating a specifically given size
4545 -- size clause or causing an unacceptable increase in size.
4547 -- Case of size clause given
4551 -- Use the inclusive size only if it is consistent with
4552 -- the explicitly specified size.
4559 -- If the inclusive size is too large, we try excluding
4560 -- the end-points (will be caught later if does not work).
4562 else
4568 -- Case of size clause not given
4570 else
4571 -- If we have a base type whose corresponding first subtype
4572 -- has an explicit size that is large enough to include our
4573 -- end-points, then do so. There is no point in working hard
4574 -- to get a base type whose size is smaller than the specified
4575 -- size of the first subtype.
4581 then
4586 -- If excluding the end-points makes the size smaller and
4587 -- results in a size of 8,16,32,64, then we take the smaller
4588 -- size. For the 64 case, this is compulsory. For the other
4589 -- cases, it seems reasonable. We like to include end points
4590 -- if we can, but not at the expense of moving to the next
4591 -- natural boundary of size.
4594 and then
4599 then
4604 -- Otherwise we can definitely include the end points
4606 else
4612 -- One pathological case: normally we never fudge a low bound
4613 -- down, since it would seem to increase the size (if it has
4614 -- any effect), but for ranges containing single value, or no
4615 -- values, the high bound can be small too large. Consider:
4617 -- type t is delta 2.0**(-14)
4618 -- range 131072.0 .. 0;
4620 -- That lower bound is *just* outside the range of 32 bits, and
4621 -- does need fudging down in this case. Note that the bounds
4622 -- will always have crossed here, since the high bound will be
4623 -- fudged down if necessary, as in the case of:
4625 -- type t is delta 2.0**(-14)
4626 -- range 131072.0 .. 131072.0;
4628 -- So we detect the situation by looking for crossed bounds,
4629 -- and if the bounds are crossed, and the low bound is greater
4630 -- than zero, we will always back it off by small, since this
4631 -- is completely harmless.
4638 -- And of course, we need to do exactly the same parallel
4639 -- fudge for flat ranges in the negative region.
4652 -- For the decimal case, none of this fudging is required, since there
4653 -- are no end-point problems in the decimal case (the end-points are
4654 -- always included).
4656 else
4660 -- At this stage, the actual size has been calculated and the proper
4661 -- required bounds are stored in the low and high bounds.
4665 Error_Msg_N
4667 Typ);
4671 -- Check size against explicit given size
4677 Error_Msg_NE
4681 else
4685 -- Increase size to next natural boundary if no size clause given
4687 else
4694 else
4702 -- If we have a base type, then expand the bounds so that they extend to
4703 -- the full width of the allocated size in bits, to avoid junk range
4704 -- checks on intermediate computations.
4711 -- Final step is to reanalyze the bounds using the proper type
4712 -- and set the Corresponding_Integer_Value fields of the literals.
4718 -- Resolve with universal fixed if the base type, and the base type if
4719 -- it is a subtype. Note we can't resolve the base type with itself,
4720 -- that would be a reference before definition.
4724 else
4728 -- Set corresponding integer value for bound
4730 Set_Corresponding_Integer_Value
4733 -- Similar processing for high bound
4741 else
4745 Set_Corresponding_Integer_Value
4748 -- Set type of range to correspond to bounds
4752 -- Set Esize to calculated size if not set already
4758 -- Set RM_Size if not already set. If already set, check value
4760 declare
4763 begin
4768 Error_Msg_NE
4773 else
4779 ------------------
4780 -- Freeze_Itype --
4781 ------------------
4786 begin
4795 --------------------------
4796 -- Freeze_Static_Object --
4797 --------------------------
4802 -- Exception raised if the type of a static object cannot be made
4803 -- static. This happens if the type depends on non-global objects.
4806 -- Called to ensure that an expression used as part of a type definition
4807 -- is statically allocatable, which means that the expression type is
4808 -- statically allocatable, and the expression is either static, or a
4809 -- reference to a library level constant.
4812 -- Called to mark a type as static, checking that it is possible
4813 -- to set the type as static. If it is not possible, then the
4814 -- exception Cannot_Be_Static is raised.
4816 -----------------------------
4817 -- Ensure_Expression_Is_SA --
4818 -----------------------------
4823 begin
4835 then
4843 -----------------------
4844 -- Ensure_Type_Is_SA --
4845 -----------------------
4851 begin
4852 -- If type is library level, we are all set
4858 -- We are also OK if the type already marked as statically allocated,
4859 -- which means we processed it before.
4865 -- Mark type as statically allocated
4869 -- Check that it is safe to statically allocate this type
4887 declare
4891 begin
4904 else
4913 then
4932 else
4937 -- Start of processing for Freeze_Static_Object
4939 begin
4942 exception
4945 -- If the object that cannot be static is imported or exported,
4946 -- then we give an error message saying that this object cannot
4947 -- be imported or exported.
4950 Error_Msg_N
4953 -- Otherwise must be exported, something is wrong if compiler
4954 -- is marking something as statically allocated which cannot be).
4957 Error_Msg_N
4962 -----------------------
4963 -- Freeze_Subprogram --
4964 -----------------------
4970 begin
4971 -- Subprogram may not have an address clause unless it is imported
4975 Error_Msg_N
4982 -- Reset the Pure indication on an imported subprogram unless an
4983 -- explicit Pure_Function pragma was present. We do this because
4984 -- otherwise it is an insidious error to call a non-pure function from
4985 -- pure unit and have calls mysteriously optimized away. What happens
4986 -- here is that the Import can bypass the normal check to ensure that
4987 -- pure units call only pure subprograms.
4992 then
4996 -- For non-foreign convention subprograms, this is where we create
4997 -- the extra formals (for accessibility level and constrained bit
4998 -- information). We delay this till the freeze point precisely so
4999 -- that we know the convention!
5005 -- If this is convention Ada and a Valued_Procedure, that's odd
5010 and then Warn_On_Export_Import
5011 then
5012 Error_Msg_N
5017 -- Case of foreign convention
5019 else
5022 -- For foreign conventions, warn about return of an
5023 -- unconstrained array.
5025 -- Note: we *do* allow a return by descriptor for the VMS case,
5026 -- though here there is probably more to be done ???
5031 -- If no return type, probably some other error, e.g. a
5032 -- missing full declaration, so ignore.
5037 -- If the return type is generic, we have emitted a warning
5038 -- earlier on, and there is nothing else to check here. Specific
5039 -- instantiations may lead to erroneous behavior.
5047 and then Warn_On_Export_Import
5048 then
5049 Error_Msg_N
5056 -- If any of the formals for an exported foreign convention
5057 -- subprogram have defaults, then emit an appropriate warning since
5058 -- this is odd (default cannot be used from non-Ada code)
5063 if Warn_On_Export_Import
5065 then
5066 Error_Msg_N
5076 -- For VMS, descriptor mechanisms for parameters are allowed only
5077 -- for imported/exported subprograms. Moreover, the NCA descriptor
5078 -- is not allowed for parameters of exported subprograms.
5085 Error_Msg_N
5087 Error_Msg_N
5098 Error_Msg_N
5100 Error_Msg_N
5109 -- Pragma Inline_Always is disallowed for dispatching subprograms
5110 -- because the address of such subprograms is saved in the dispatch
5111 -- table to support dispatching calls, and dispatching calls cannot
5112 -- be inlined. This is consistent with the restriction against using
5113 -- 'Access or 'Address on an Inline_Always subprogram.
5117 then
5118 Error_Msg_N
5122 -- Because of the implicit representation of inherited predefined
5123 -- operators in the front-end, the overriding status of the operation
5124 -- may be affected when a full view of a type is analyzed, and this is
5125 -- not captured by the analysis of the corresponding type declaration.
5126 -- Therefore the correctness of a not-overriding indicator must be
5127 -- rechecked when the subprogram is frozen.
5131 then
5136 ----------------------
5137 -- Is_Fully_Defined --
5138 ----------------------
5141 begin
5150 then
5151 -- Verify that the record type has no components with private types
5152 -- without completion.
5154 declare
5157 begin
5170 else
5176 ---------------------------------
5177 -- Generate_Prim_Op_References --
5178 ---------------------------------
5186 begin
5187 -- Handle subtypes of synchronized types
5191 then
5193 else
5197 -- References to primitive operations are only relevant for tagged types
5201 then
5205 -- Ada 2005 (AI-345): For synchronized types generate reference
5206 -- to the wrapper that allow us to dispatch calls through their
5207 -- implemented abstract interface types.
5209 -- The check for Present here is to protect against previously
5210 -- reported critical errors.
5214 then
5215 Prim_List := Primitive_Operations
5217 else
5228 -- If the operation is derived, get the original for cross-reference
5229 -- reference purposes (it is the original for which we want the xref
5230 -- and for which the comes_from_source test must be performed).
5242 ---------------------------------
5243 -- Process_Default_Expressions --
5244 ---------------------------------
5246 procedure Process_Default_Expressions
5249 is
5256 begin
5259 -- A subprogram instance and its associated anonymous subprogram share
5260 -- their signature. The default expression functions are defined in the
5261 -- wrapper packages for the anonymous subprogram, and should not be
5262 -- generated again for the instance.
5267 then
5275 -- We work with a copy of the default expression because we
5276 -- do not want to disturb the original, since this would mess
5277 -- up the conformance checking.
5281 -- The analysis of the expression may generate insert actions,
5282 -- which of course must not be executed. We wrap those actions
5283 -- in a procedure that is not called, and later on eliminated.
5284 -- The following cases have no side-effects, and are analyzed
5285 -- directly.
5296 and then
5298 then
5300 -- If there is no default function, we must still do a full
5301 -- analyze call on the default value, to ensure that all error
5302 -- checks are performed, e.g. those associated with static
5303 -- evaluation. Note: this branch will always be taken if the
5304 -- analyzer is turned off (but we still need the error checks).
5306 -- Note: the setting of parent here is to meet the requirement
5307 -- that we can only analyze the expression while attached to
5308 -- the tree. Really the requirement is that the parent chain
5309 -- be set, we don't actually need to be in the tree.
5314 -- Default expressions are resolved with their own type if the
5315 -- context is generic, to avoid anomalies with private types.
5319 else
5323 -- If that resolved expression will raise constraint error,
5324 -- then flag the default value as raising constraint error.
5325 -- This allows a proper error message on the calls.
5331 -- If the default is a parameterless call, we use the name of
5332 -- the called function directly, and there is no body to build.
5336 then
5339 -- Else construct and analyze the body of a wrapper procedure
5340 -- that contains an object declaration to hold the expression.
5341 -- Given that this is done only to complete the analysis, it
5342 -- simpler to build a procedure than a function which might
5343 -- involve secondary stack expansion.
5345 else
5346 Dnam :=
5349 Dbody :=
5351 Specification =>
5357 Defining_Identifier =>
5360 Object_Definition =>
5364 Handled_Statement_Sequence =>
5381 ----------------------------------------
5382 -- Set_Component_Alignment_If_Not_Set --
5383 ----------------------------------------
5386 begin
5387 -- Ignore if not base type, subtypes don't need anything
5393 -- Do not override existing representation
5404 else
5405 Set_Component_Alignment
5411 ------------------
5412 -- Undelay_Type --
5413 ------------------
5416 begin
5420 -- Since we don't want T to have a Freeze_Node, we don't want its
5421 -- Full_View or Corresponding_Record_Type to have one either.
5423 -- ??? Fundamentally, this whole handling is a kludge. What we really
5424 -- want is to be sure that for an Itype that's part of record R and is a
5425 -- subtype of type T, that it's frozen after the later of the freeze
5426 -- points of R and T. We have no way of doing that directly, so what we
5427 -- do is force most such Itypes to be frozen as part of freezing R via
5428 -- this procedure and only delay the ones that need to be delayed
5429 -- (mostly the designated types of access types that are defined as part
5430 -- of the record).
5436 then
5444 then
5449 ------------------
5450 -- Warn_Overlay --
5451 ------------------
5453 procedure Warn_Overlay
5457 is
5459 -- The object to which the address clause applies
5465 begin
5466 -- No warning if address clause overlay warnings are off
5472 -- No warning if there is an explicit initialization
5480 -- We only give the warning for non-imported entities of a type for
5481 -- which a non-null base init proc is defined, or for objects of access
5482 -- types with implicit null initialization, or when Initialize_Scalars
5483 -- applies and the type is scalar or a string type (the latter being
5484 -- tested for because predefined String types are initialized by inline
5485 -- code rather than by an init_proc).
5494 then
5497 then
5502 then
5509 then
5516 -- A function call (most likely to To_Address) is probably not an
5517 -- overlay, so skip warning. Ditto if the function call was inlined
5518 -- and transformed into an entity.
5526 -- If a pragma Import follows, we assume that it is for the current
5527 -- target of the address clause, and skip the warning.
5532 then
5538 Error_Msg_N
5540 Nam);
5541 else
5542 Error_Msg_N
5544 Nam);
5547 -- Add friendly warning if initialization comes from a packed array
5548 -- component.
5551 declare
5554 begin
5560 then
5564 then
5565 Error_Msg_NE
5570 else
5577 Error_Msg_N
5580 Nam);