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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) 1992-2011, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
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. N has
107 -- the same usage as in Freeze_Entity.
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.
138 procedure Process_Default_Expressions
141 -- This procedure is called for each subprogram to complete processing of
142 -- default expressions at the point where all types are known to be frozen.
143 -- The expressions must be analyzed in full, to make sure that all error
144 -- processing is done (they have only been pre-analyzed). If the expression
145 -- is not an entity or literal, its analysis may generate code which must
146 -- not be executed. In that case we build a function body to hold that
147 -- code. This wrapper function serves no other purpose (it used to be
148 -- called to evaluate the default, but now the default is inlined at each
149 -- point of call).
152 -- Typ is a record or array type that is being frozen. This routine sets
153 -- the default component alignment from the scope stack values if the
154 -- alignment is otherwise not specified.
157 -- As each entity is frozen, this routine is called to deal with the
158 -- setting of Debug_Info_Needed for the entity. This flag is set if
159 -- the entity comes from source, or if we are in Debug_Generated_Code
160 -- mode or if the -gnatdV debug flag is set. However, it never sets
161 -- the flag if Debug_Info_Off is set. This procedure also ensures that
162 -- subsidiary entities have the flag set as required.
165 -- T is a type of a component that we know to be an Itype. We don't want
166 -- this to have a Freeze_Node, so ensure it doesn't. Do the same for any
167 -- Full_View or Corresponding_Record_Type.
169 procedure Warn_Overlay
173 -- Expr is the expression for an address clause for entity Nam whose type
174 -- is Typ. If Typ has a default initialization, and there is no explicit
175 -- initialization in the source declaration, check whether the address
176 -- clause might cause overlaying of an entity, and emit a warning on the
177 -- side effect that the initialization will cause.
179 -------------------------------
180 -- Adjust_Esize_For_Alignment --
181 -------------------------------
186 begin
192 then
198 ------------------------------------
199 -- Build_And_Analyze_Renamed_Body --
200 ------------------------------------
202 procedure Build_And_Analyze_Renamed_Body
206 is
212 begin
213 -- If the renamed subprogram is intrinsic, there is no need for a
214 -- wrapper body: we set the alias that will be called and expanded which
215 -- completes the declaration. This transformation is only legal if the
216 -- renamed entity has already been elaborated.
218 -- Note that it is legal for a renaming_as_body to rename an intrinsic
219 -- subprogram, as long as the renaming occurs before the new entity
220 -- is frozen. See RM 8.5.4 (5).
224 then
226 else
232 and then
236 -- We can make the renaming entity intrinsic if the renamed function
237 -- has an interface name, or if it is one of the shift/rotate
238 -- operations known to the compiler.
246 then
251 else
258 else
267 ------------------------
268 -- Build_Renamed_Body --
269 ------------------------
271 function Build_Renamed_Body
274 is
276 -- We use for the source location of the renamed body, the location of
277 -- the spec entity. It might seem more natural to use the location of
278 -- the renaming declaration itself, but that would be wrong, since then
279 -- the body we create would look as though it was created far too late,
280 -- and this could cause problems with elaboration order analysis,
281 -- particularly in connection with instantiations.
296 -- If the renamed entity is a primitive operation given in prefix form,
297 -- the prefix is the target object and it has to be added as the first
298 -- actual in the generated call.
300 begin
301 -- Determine the entity being renamed, which is the target of the call
302 -- statement. If the name is an explicit dereference, this is a renaming
303 -- of a subprogram type rather than a subprogram. The name itself is
304 -- fully analyzed.
315 else
322 else
328 -- If the renamed entity is a predefined operator, retain full name
329 -- to ensure its visibility.
333 then
335 else
339 else
342 and then
345 then
347 -- Retrieve the target object, to be added as a first actual
348 -- in the call.
353 else
357 -- Original name may have been overloaded, but is fully resolved now
362 -- For simple renamings, subsequent calls can be expanded directly as
363 -- calls to the renamed entity. The body must be generated in any case
364 -- for calls that may appear elsewhere. This is not done in the case
365 -- where the subprogram is an instantiation because the actual proper
366 -- body has not been built yet.
371 then
375 -- The body generated for this renaming is an internal artifact, and
376 -- does not constitute a freeze point for the called entity.
383 declare
387 begin
388 -- The controlling formal may be an access parameter, or the
389 -- actual may be an access value, so adjust accordingly.
393 then
394 Actuals := New_List
399 then
400 Actuals := New_List
404 else
412 else
423 -- If the renamed entity is an entry, inherit its profile. For other
424 -- renamings as bodies, both profiles must be subtype conformant, so it
425 -- is not necessary to replace the profile given in the declaration.
426 -- However, default values that are aggregates are rewritten when
427 -- partially analyzed, so we recover the original aggregate to insure
428 -- that subsequent conformity checking works. Similarly, if the default
429 -- expression was constant-folded, recover the original expression.
439 N_Access_Definition
440 then
448 then
459 -- If the renamed entity is a function, the generated body contains a
460 -- return statement. Otherwise, build a procedure call. If the entity is
461 -- an entry, subsequent analysis of the call will transform it into the
462 -- proper entry or protected operation call. If the renamed entity is
463 -- a character literal, return it directly.
469 then
470 Call_Node :=
472 Expression =>
478 Call_Node :=
483 Call_Node :=
487 else
488 Call_Node :=
494 -- Create entities for subprogram body and formals
507 Body_Node :=
511 Handled_Statement_Sequence =>
521 -- Link the body to the entity whose declaration it completes. If
522 -- the body is analyzed when the renamed entity is frozen, it may
523 -- be necessary to restore the proper scope (see package Exp_Ch13).
527 then
529 else
536 --------------------------
537 -- Check_Address_Clause --
538 --------------------------
546 begin
553 -- Has_Delayed_Freeze was set on E when the address clause was
554 -- analyzed. Reset the flag now unless freeze actions were
555 -- attached to it in the mean time.
562 -- If Rep_Clauses are to be ignored, remove address clause from
563 -- list attached to entity, because it may be illegal for gigi,
564 -- for example by breaking order of elaboration..
567 declare
570 begin
576 else
579 loop
593 then
599 -----------------------------
600 -- Check_Compile_Time_Size --
601 -----------------------------
606 -- Sets the compile time known size (32 bits or less) in the Esize
607 -- field, of T checking for a size clause that was given which attempts
608 -- to give a smaller size, and also checking for an alignment clause.
611 -- Recursive function that does all the work
614 -- If T is a constrained subtype, its size is not known if any of its
615 -- discriminant constraints is not static and it is not a null record.
616 -- The test is conservative and doesn't check that the components are
617 -- in fact constrained by non-static discriminant values. Could be made
618 -- more precise ???
620 --------------------
621 -- Set_Small_Size --
622 --------------------
625 begin
629 -- Check for bad size clause given
634 Error_Msg_NE
639 -- Set size if not set already
646 ----------------
647 -- Size_Known --
648 ----------------
657 begin
661 -- Always True for scalar types. This is true even for generic formal
662 -- scalar types. We used to return False in the latter case, but the
663 -- size is known at compile time, even in the template, we just do
664 -- not know the exact size but that's not the point of this routine.
668 then
671 -- Array types
675 -- String literals always have known size, and we can set it
682 -- Unconstrained types never have known at compile time size
687 -- Don't do any recursion on type with error posted, since we may
688 -- have a malformed type that leads us into a loop.
693 -- Otherwise if component size unknown, then array size unknown
699 -- Check for all indexes static, and also compute possible size
700 -- (in case it is less than 32 and may be packable).
702 declare
706 begin
715 else
723 then
726 else
731 else
743 -- Access types always have known at compile time sizes
748 -- For non-generic private types, go to underlying type if present
753 then
754 -- Don't do any recursion on type with error posted, since we may
755 -- have a malformed type that leads us into a loop.
759 else
763 -- Record types
767 -- A class-wide type is never considered to have a known size
772 -- A subtype of a variant record must not have non-static
773 -- discriminated components.
777 then
780 -- Don't do any recursion on type with error posted, since we may
781 -- have a malformed type that leads us into a loop.
787 -- Now look at the components of the record
789 declare
790 -- The following two variables are used to keep track of the
791 -- size of packed records if we can tell the size of the packed
792 -- record in the front end. Packed_Size_Known is True if so far
793 -- we can figure out the size. It is initialized to True for a
794 -- packed record, unless the record has discriminants. The
795 -- reason we eliminate the discriminated case is that we don't
796 -- know the way the back end lays out discriminated packed
797 -- records. If Packed_Size_Known is True, then Packed_Size is
798 -- the size in bits so far.
806 begin
807 -- Test for variant part present
813 N_Record_Definition
817 then
818 -- If variant part is present, and type is unconstrained,
819 -- then we must have defaulted discriminants, or a size
820 -- clause must be present for the type, or else the size
821 -- is definitely not known at compile time.
824 and then
827 then
832 -- Loop through components
838 -- We do not know the packed size if there is a component
839 -- clause present (we possibly could, but this would only
840 -- help in the case of a record with partial rep clauses.
841 -- That's because in the case of full rep clauses, the
842 -- size gets figured out anyway by a different circuit).
848 -- We need to identify a component that is an array where
849 -- the index type is an enumeration type with non-standard
850 -- representation, and some bound of the type depends on a
851 -- discriminant.
853 -- This is because gigi computes the size by doing a
854 -- substitution of the appropriate discriminant value in
855 -- the size expression for the base type, and gigi is not
856 -- clever enough to evaluate the resulting expression (which
857 -- involves a call to rep_to_pos) at compile time.
859 -- It would be nice if gigi would either recognize that
860 -- this expression can be computed at compile time, or
861 -- alternatively figured out the size from the subtype
862 -- directly, where all the information is at hand ???
866 then
867 declare
875 begin
882 then
888 then
893 then
903 -- Clearly size of record is not known if the size of one of
904 -- the components is not known.
910 -- Accumulate packed size if possible
914 -- We can only deal with elementary types, since for
915 -- non-elementary components, alignment enters into the
916 -- picture, and we don't know enough to handle proper
917 -- alignment in this context. Packed arrays count as
918 -- elementary if the representation is a modular type.
923 and then Is_Modular_Integer_Type
925 then
926 -- If RM_Size is known and static, then we can keep
927 -- accumulating the packed size.
931 -- A little glitch, to be removed sometime ???
932 -- gigi does not understand zero sizes yet.
937 -- Normal case where we can keep accumulating the
938 -- packed array size.
940 else
944 -- If we have a field whose RM_Size is not known then
945 -- we can't figure out the packed size here.
947 else
951 -- If we have a non-elementary type we can't figure out
952 -- the packed array size (alignment issues).
954 else
969 -- All other cases, size not known at compile time
971 else
976 -------------------------------------
977 -- Static_Discriminated_Components --
978 -------------------------------------
980 function Static_Discriminated_Components
982 is
985 begin
989 then
1003 -- Start of processing for Check_Compile_Time_Size
1005 begin
1009 -----------------------------
1010 -- Check_Debug_Info_Needed --
1011 -----------------------------
1014 begin
1019 or else Debug_Generated_Code
1020 or else Debug_Flag_VV
1022 then
1027 ----------------------------
1028 -- Check_Strict_Alignment --
1029 ----------------------------
1034 begin
1052 then
1062 -------------------------
1063 -- Check_Unsigned_Type --
1064 -------------------------
1071 begin
1076 -- Do not attempt to analyze case where range was in error
1080 then
1084 -- The situation that is non trivial is something like
1086 -- subtype x1 is integer range -10 .. +10;
1087 -- subtype x2 is x1 range 0 .. V1;
1088 -- subtype x3 is x2 range V2 .. V3;
1089 -- subtype x4 is x3 range V4 .. V5;
1091 -- where Vn are variables. Here the base type is signed, but we still
1092 -- know that x4 is unsigned because of the lower bound of x2.
1094 -- The only way to deal with this is to look up the ancestor chain
1097 loop
1112 else
1115 -- If no ancestor had a static lower bound, go to base type
1119 -- Note: the reason we still check for a compile time known
1120 -- value for the base type is that at least in the case of
1121 -- generic formals, we can have bounds that fail this test,
1122 -- and there may be other cases in error situations.
1134 then
1144 -------------------------
1145 -- Is_Atomic_Aggregate --
1146 -------------------------
1148 function Is_Atomic_Aggregate
1151 is
1157 begin
1160 -- Array may be qualified, so find outer context
1168 then
1170 New_N :=
1181 else
1186 ----------------
1187 -- Freeze_All --
1188 ----------------
1190 -- Note: the easy coding for this procedure would be to just build a
1191 -- single list of freeze nodes and then insert them and analyze them
1192 -- all at once. This won't work, because the analysis of earlier freeze
1193 -- nodes may recursively freeze types which would otherwise appear later
1194 -- on in the freeze list. So we must analyze and expand the freeze nodes
1195 -- as they are generated.
1202 -- This is the internal recursive routine that does freezing of entities
1203 -- (but NOT the analysis of default expressions, which should not be
1204 -- recursive, we don't want to analyze those till we are sure that ALL
1205 -- the types are frozen).
1207 --------------------
1208 -- Freeze_All_Ent --
1209 --------------------
1217 -- If freeze nodes are present, insert and analyze, and reset cursor
1218 -- for next insertion.
1220 -------------------
1221 -- Process_Flist --
1222 -------------------
1225 begin
1232 else
1238 -- Start or processing for Freeze_All_Ent
1240 begin
1244 -- If the entity is an inner package which is not a package
1245 -- renaming, then its entities must be frozen at this point. Note
1246 -- that such entities do NOT get frozen at the end of the nested
1247 -- package itself (only library packages freeze).
1249 -- Same is true for task declarations, where anonymous records
1250 -- created for entry parameters must be frozen.
1256 then
1267 then
1273 and then
1275 or else
1277 then
1280 End_Scope;
1282 -- For a derived tagged type, we must ensure that all the
1283 -- primitive operations of the parent have been frozen, so that
1284 -- their addresses will be in the parent's dispatch table at the
1285 -- point it is inherited.
1291 then
1292 declare
1299 begin
1306 then
1308 Process_Flist;
1318 Process_Flist;
1320 -- If already frozen, and there are delayed aspects, this is where
1321 -- we do the visibility check for these aspects (see Sem_Ch13 spec
1322 -- for a description of how we handle aspect visibility).
1325 declare
1328 begin
1334 then
1343 -- If an incomplete type is still not frozen, this may be a
1344 -- premature freezing because of a body declaration that follows.
1345 -- Indicate where the freezing took place.
1347 -- If the freezing is caused by the end of the current declarative
1348 -- part, it is a Taft Amendment type, and there is no error.
1352 then
1353 declare
1356 begin
1358 N_Entry_Body,
1359 N_Package_Body,
1360 N_Protected_Body,
1361 N_Task_Body)
1363 and then
1365 then
1367 Error_Msg_NE
1378 -- Start of processing for Freeze_All
1380 begin
1383 -- Now that all types are frozen, we can deal with default expressions
1384 -- that require us to build a default expression functions. This is the
1385 -- point at which such functions are constructed (after all types that
1386 -- might be used in such expressions have been frozen).
1388 -- For subprograms that are renaming_as_body, we create the wrapper
1389 -- bodies as needed.
1391 -- We also add finalization chains to access types whose designated
1392 -- types are controlled. This is normally done when freezing the type,
1393 -- but this misses recursive type definitions where the later members
1394 -- of the recursion introduce controlled components.
1396 -- Loop through entities
1412 else
1418 and then
1420 = N_Subprogram_Renaming_Declaration
1421 then
1422 Build_And_Analyze_Renamed_Body
1428 and then
1430 or else
1432 then
1433 declare
1436 begin
1441 then
1449 -- We add finalization masters to access types whose designated types
1450 -- require finalization. This is normally done when freezing the
1451 -- type, but this misses recursive type definitions where the later
1452 -- members of the recursion introduce controlled components (such as
1453 -- can happen when incomplete types are involved), as well cases
1454 -- where a component type is private and the controlled full type
1455 -- occurs after the access type is frozen. Cases that don't need a
1456 -- finalization master are generic formal types (the actual type will
1457 -- have it) and types with Java and CIL conventions, since those are
1458 -- used for API bindings. (Are there any other cases that should be
1459 -- excluded here???)
1465 then
1473 -----------------------
1474 -- Freeze_And_Append --
1475 -----------------------
1477 procedure Freeze_And_Append
1481 is
1483 begin
1487 else
1493 -------------------
1494 -- Freeze_Before --
1495 -------------------
1499 begin
1505 -------------------
1506 -- Freeze_Entity --
1507 -------------------
1519 -- List of freezing actions, left at No_List if none
1522 -- This flag gets set to true for a variable with default initialization
1525 -- N is a freezing action to be appended to the Result
1528 -- Check that an Access or Unchecked_Access attribute with a prefix
1529 -- which is the current instance type can only be applied when the type
1530 -- is limited.
1533 -- Give warning for modulus of 8, 16, 32, or 64 given as an explicit
1534 -- integer literal without an explicit corresponding size clause. The
1535 -- caller has checked that Utype is a modular integer type.
1538 -- If Loc is a freeze_entity that appears after the last declaration
1539 -- in the scope, inhibit error messages on late completion.
1542 -- Freeze each component, handle some representation clauses, and freeze
1543 -- primitive operations if this is a tagged type.
1545 -------------------
1546 -- Add_To_Result --
1547 -------------------
1550 begin
1553 else
1558 ----------------------------
1559 -- After_Last_Declaration --
1560 ----------------------------
1564 begin
1570 else
1573 else
1578 ----------------------------
1579 -- Check_Current_Instance --
1580 ----------------------------
1590 -- Process routine to apply check to given node
1592 -------------
1593 -- Process --
1594 -------------
1597 begin
1601 or else
1606 then
1607 Error_Msg_N
1610 else
1620 -- Start of processing for Check_Current_Instance
1622 begin
1623 -- In Ada 95, the (imprecise) rule is that the current instance
1624 -- of a limited type is aliased. In Ada 2005, limitedness must be
1625 -- explicit: either a tagged type, or a limited record.
1629 then
1634 then
1637 else
1642 ------------------------------
1643 -- Check_Suspicious_Modulus --
1644 ------------------------------
1649 begin
1651 declare
1654 begin
1656 declare
1659 begin
1661 declare
1665 begin
1666 -- First case, modulus and size are the same. This
1667 -- happens if you have something like mod 32, with
1668 -- an explicit size of 32, this is for sure a case
1669 -- where the warning is given, since it is seems
1670 -- very unlikely that someone would want e.g. a
1671 -- five bit type stored in 32 bits. It is much
1672 -- more likely they wanted a 32-bit type.
1677 -- Second case, the modulus is 32 or 64 and no
1678 -- size clause is present. This is a less clear
1679 -- case for giving the warning, but in the case
1680 -- of 32/64 (5-bit or 6-bit types) these seem rare
1681 -- enough that it is a likely error (and in any
1682 -- case using 2**5 or 2**6 in these cases seems
1683 -- clearer. We don't include 8 or 16 here, simply
1684 -- because in practice 3-bit and 4-bit types are
1685 -- more common and too many false positives if
1686 -- we warn in these cases.
1690 then
1693 -- No warning needed
1695 else
1699 -- If we fall through, give warning
1702 Error_Msg_N
1704 Modulus);
1713 ------------------------
1714 -- Freeze_Record_Type --
1715 ------------------------
1727 -- Set True if we find at least one component with no component
1728 -- clause (used to warn about useless Pack pragmas).
1731 -- Set True if we find at least one component with a component
1732 -- clause (used to warn about useless Bit_Order pragmas, and also
1733 -- to detect cases where Implicit_Packing may have an effect).
1736 -- Set False if we encounter a component of a non-scalar type
1740 -- Accumulates total RM_Size values and total Esize values of all
1741 -- scalar components. Used for processing of Implicit_Packing.
1744 -- If N is an allocator, possibly wrapped in one or more level of
1745 -- qualified expression(s), return the inner allocator node, else
1746 -- return Empty.
1749 -- If the component subtype is an access to a constrained subtype of
1750 -- an already frozen type, make the subtype frozen as well. It might
1751 -- otherwise be frozen in the wrong scope, and a freeze node on
1752 -- subtype has no effect. Similarly, if the component subtype is a
1753 -- regular (not protected) access to subprogram, set the anonymous
1754 -- subprogram type to frozen as well, to prevent an out-of-scope
1755 -- freeze node at some eventual point of call. Protected operations
1756 -- are handled elsewhere.
1758 ---------------------
1759 -- Check_Allocator --
1760 ---------------------
1764 begin
1766 loop
1771 else
1777 -----------------
1778 -- Check_Itype --
1779 -----------------
1784 begin
1787 then
1790 -- In addition, add an Itype_Reference to ensure that the
1791 -- access subtype is elaborated early enough. This cannot be
1792 -- done if the subtype may depend on discriminants.
1797 then
1805 then
1810 -- Start of processing for Freeze_Record_Type
1812 begin
1813 -- Freeze components and embedded subtypes
1819 -- First handle the component case
1823 then
1824 declare
1827 begin
1828 -- Freezing a record type freezes the type of each of its
1829 -- components. However, if the type of the component is
1830 -- part of this record, we do not want or need a separate
1831 -- Freeze_Node. Note that Is_Itype is wrong because that's
1832 -- also set in private type cases. We also can't check for
1833 -- the Scope being exactly Rec because of private types and
1834 -- record extensions.
1839 then
1845 -- Check for error of component clause given for variable
1846 -- sized type. We have to delay this test till this point,
1847 -- since the component type has to be frozen for us to know
1848 -- if it is variable length. We omit this test in a generic
1849 -- context, it will be applied at instantiation time.
1851 -- We also omit this test in CodePeer mode, since we do not
1852 -- have sufficient info on size and representation clauses.
1863 elsif not
1864 Size_Known_At_Compile_Time
1866 then
1867 Error_Msg_N
1872 else
1876 -- Case of component requires byte alignment
1880 -- Set the enclosing record to also require byte align
1884 -- Check for component clause that is inconsistent with
1885 -- the required byte boundary alignment.
1890 then
1891 Error_Msg_N
1899 -- Gather data for possible Implicit_Packing later. Note that at
1900 -- this stage we might be dealing with a real component, or with
1901 -- an implicit subtype declaration.
1905 else
1906 Scalar_Component_Total_RM_Size :=
1908 Scalar_Component_Total_Esize :=
1912 -- If the component is an Itype with Delayed_Freeze and is either
1913 -- a record or array subtype and its base type has not yet been
1914 -- frozen, we must remove this from the entity list of this record
1915 -- and put it on the entity list of the scope of its base type.
1916 -- Note that we know that this is not the type of a component
1917 -- since we cleared Has_Delayed_Freeze for it in the previous
1918 -- loop. Thus this must be the Designated_Type of an access type,
1919 -- which is the type of a component.
1927 then
1928 declare
1932 begin
1933 -- We have a pretty bad kludge here. Suppose Rec is subtype
1934 -- being defined in a subprogram that's created as part of
1935 -- the freezing of Rec'Base. In that case, we know that
1936 -- Comp'Base must have already been frozen by the time we
1937 -- get to elaborate this because Gigi doesn't elaborate any
1938 -- bodies until it has elaborated all of the declarative
1939 -- part. But Is_Frozen will not be set at this point because
1940 -- we are processing code in lexical order.
1942 -- We detect this case by going up the Scope chain of Rec
1943 -- and seeing if we have a subprogram scope before reaching
1944 -- the top of the scope chain or that of Comp'Base. If we
1945 -- do, then mark that Comp'Base will actually be frozen. If
1946 -- so, we merely undelay it.
1962 else
1965 else
1969 -- Insert in entity list of scope of base type (which
1970 -- must be an enclosing scope, because still unfrozen).
1976 -- If the component is an access type with an allocator as default
1977 -- value, the designated type will be frozen by the corresponding
1978 -- expression in init_proc. In order to place the freeze node for
1979 -- the designated type before that for the current record type,
1980 -- freeze it now.
1982 -- Same process if the component is an array of access types,
1983 -- initialized with an aggregate. If the designated type is
1984 -- private, it cannot contain allocators, and it is premature
1985 -- to freeze the type, so we check for this as well.
1990 then
1991 declare
1995 begin
1998 -- If component is pointer to a classwide type, freeze
1999 -- the specific type in the expression being allocated.
2000 -- The expression may be a subtype indication, in which
2001 -- case freeze the subtype mark.
2003 if Is_Class_Wide_Type
2005 then
2007 Freeze_And_Append
2009 elsif
2011 then
2012 Freeze_And_Append
2020 else
2021 Freeze_And_Append
2029 then
2038 and then Is_Fully_Defined
2040 then
2041 Freeze_And_Append
2042 (Designated_Type
2050 -- Deal with Bit_Order aspect specifying a non-default bit order
2054 ADC :=
2057 Error_Msg_N
2060 -- Here is where we do the processing for reversed bit order
2062 else
2067 -- Complete error checking on record representation clause (e.g.
2068 -- overlap of components). This is called after adjusting the
2069 -- record for reverse bit order.
2071 declare
2073 begin
2079 -- Set OK_To_Reorder_Components depending on debug flags
2083 or else
2085 then
2090 -- Check for useless pragma Pack when all components placed. We only
2091 -- do this check for record types, not subtypes, since a subtype may
2092 -- have all its components placed, and it still makes perfectly good
2093 -- sense to pack other subtypes or the parent type. We do not give
2094 -- this warning if Optimize_Alignment is set to Space, since the
2095 -- pragma Pack does have an effect in this case (it always resets
2096 -- the alignment to one).
2100 and then not Unplaced_Component
2102 then
2103 -- Reset packed status. Probably not necessary, but we do it so
2104 -- that there is no chance of the back end doing something strange
2105 -- with this redundant indication of packing.
2109 -- Give warning if redundant constructs warnings on
2112 Error_Msg_N -- CODEFIX
2118 -- If this is the record corresponding to a remote type, freeze the
2119 -- remote type here since that is what we are semantically freezing.
2120 -- This prevents the freeze node for that type in an inner scope.
2122 -- Also, Check for controlled components and unchecked unions.
2123 -- Finally, enforce the restriction that access attributes with a
2124 -- current instance prefix can only apply to limited types.
2134 -- Do not set Has_Controlled_Component on a class-wide
2135 -- equivalent type. See Make_CW_Equivalent_Type.
2142 and then Present
2143 (Corresponding_Record_Type
2145 and then Has_Controlled_Component
2146 (Corresponding_Record_Type
2148 then
2159 -- Scan component declaration for likely misuses of current
2160 -- instance, either in a constraint or a default expression.
2171 -- For first subtypes, check if there are any fixed-point fields with
2172 -- component clauses, where we must check the size. This is not done
2173 -- till the freeze point, since for fixed-point types, we do not know
2174 -- the size until the type is frozen. Similar processing applies to
2175 -- bit packed arrays.
2182 or else
2184 then
2185 Check_Size
2189 Junk);
2196 -- Generate warning for applying C or C++ convention to a record
2197 -- with discriminants. This is suppressed for the unchecked union
2198 -- case, since the whole point in this case is interface C. We also
2199 -- do not generate this within instantiations, since we will have
2200 -- generated a message on the template.
2205 or else
2208 and then not In_Instance
2211 then
2212 declare
2216 begin
2221 Error_Msg_N
2223 else
2224 Error_Msg_N
2228 Error_Msg_NE
2234 -- See if Size is too small as is (and implicit packing might help)
2238 -- No implicit packing if even one component is explicitly placed
2240 and then not Placed_Component
2242 -- Must have size clause and all scalar components
2245 and then All_Scalar_Components
2247 -- Do not try implicit packing on records with discriminants, too
2248 -- complicated, especially in the variant record case.
2252 -- We can implicitly pack if the specified size of the record is
2253 -- less than the sum of the object sizes (no point in packing if
2254 -- this is not the case).
2258 -- And the total RM size cannot be greater than the specified size
2259 -- since otherwise packing will not get us where we have to be!
2263 -- Never do implicit packing in CodePeer or Alfa modes since
2264 -- we don't do any packing in these modes, since this generates
2265 -- over-complex code that confuses static analysis, and in
2266 -- general, neither CodePeer not GNATprove care about the
2267 -- internal representation of objects.
2270 then
2271 -- If implicit packing enabled, do it
2276 -- Otherwise flag the size clause
2278 else
2279 declare
2281 begin
2282 Error_Msg_NE -- CODEFIX
2284 Error_Msg_N -- CODEFIX
2292 -- Start of processing for Freeze_Entity
2294 begin
2295 -- We are going to test for various reasons why this entity need not be
2296 -- frozen here, but in the case of an Itype that's defined within a
2297 -- record, that test actually applies to the record.
2303 then
2307 -- Do not freeze if already frozen since we only need one freeze node
2312 -- It is improper to freeze an external entity within a generic because
2313 -- its freeze node will appear in a non-valid context. The entity will
2314 -- be frozen in the proper scope after the current generic is analyzed.
2319 -- AI05-0213: A formal incomplete type does not freeze the actual. In
2320 -- the instance, the same applies to the subtype renaming the actual.
2326 then
2329 -- Do not freeze a global entity within an inner scope created during
2330 -- expansion. A call to subprogram E within some internal procedure
2331 -- (a stream attribute for example) might require freezing E, but the
2332 -- freeze node must appear in the same declarative part as E itself.
2333 -- The two-pass elaboration mechanism in gigi guarantees that E will
2334 -- be frozen before the inner call is elaborated. We exclude constants
2335 -- from this test, because deferred constants may be frozen early, and
2336 -- must be diagnosed (e.g. in the case of a deferred constant being used
2337 -- in a default expression). If the enclosing subprogram comes from
2338 -- source, or is a generic instance, then the freeze point is the one
2339 -- mandated by the language, and we freeze the entity. A subprogram that
2340 -- is a child unit body that acts as a spec does not have a spec that
2341 -- comes from source, but can only come from source.
2346 then
2347 declare
2350 begin
2357 then
2359 else
2368 -- Similarly, an inlined instance body may make reference to global
2369 -- entities, but these references cannot be the proper freezing point
2370 -- for them, and in the absence of inlining freezing will take place in
2371 -- their own scope. Normally instance bodies are analyzed after the
2372 -- enclosing compilation, and everything has been frozen at the proper
2373 -- place, but with front-end inlining an instance body is compiled
2374 -- before the end of the enclosing scope, and as a result out-of-order
2375 -- freezing must be prevented.
2377 elsif Front_End_Inlining
2378 and then In_Instance_Body
2380 then
2381 declare
2384 begin
2389 else
2400 -- Deal with delayed aspect specifications. The analysis of the aspect
2401 -- is required to be delayed to the freeze point, so we evaluate the
2402 -- pragma or attribute definition clause in the tree at this point.
2405 declare
2409 begin
2410 -- Look for aspect specification entries for this entity
2418 then
2421 -- Skip if this is an aspect with no corresponding pragma
2422 -- or attribute definition node (such as Default_Value).
2435 -- Here to freeze the entity
2439 -- Case of entity being frozen is other than a type
2443 -- If entity is exported or imported and does not have an external
2444 -- name, now is the time to provide the appropriate default name.
2445 -- Skip this if the entity is stubbed, since we don't need a name
2446 -- for any stubbed routine. For the case on intrinsics, if no
2447 -- external name is specified, then calls will be handled in
2448 -- Exp_Intr.Expand_Intrinsic_Call, and no name is needed. If an
2449 -- external name is provided, then Expand_Intrinsic_Call leaves
2450 -- calls in place for expansion by GIGI.
2456 then
2457 Set_Encoded_Interface_Name
2460 -- If entity is an atomic object appearing in a declaration and
2461 -- the expression is an aggregate, assign it to a temporary to
2462 -- ensure that the actual assignment is done atomically rather
2463 -- than component-wise (the assignment to the temp may be done
2464 -- component-wise, but that is harmless).
2471 then
2475 -- For a subprogram, freeze all parameter types and also the return
2476 -- type (RM 13.14(14)). However skip this for internal subprograms.
2477 -- This is also the point where any extra formal parameters are
2478 -- created since we now know whether the subprogram will use a
2479 -- foreign convention.
2483 declare
2488 begin
2489 -- Loop through formals
2495 -- AI05-0151 : incomplete types can appear in a profile.
2496 -- By the time the entity is frozen, the full view must
2497 -- be available, unless it is a limited view.
2501 then
2513 then
2514 -- If the type of a formal is incomplete, subprogram
2515 -- is being frozen prematurely. Within an instance
2516 -- (but not within a wrapper package) this is an
2517 -- artifact of our need to regard the end of an
2518 -- instantiation as a freeze point. Otherwise it is
2519 -- a definite error.
2525 elsif not After_Last_Declaration
2526 and then not Freezing_Library_Level_Tagged_Type
2527 then
2529 Error_Msg
2531 Loc);
2535 -- Check suspicious parameter for C function. These tests
2536 -- apply only to exported/imported subprograms.
2538 if Warn_On_Export_Import
2541 or else
2548 then
2549 -- Qualify mention of formals with subprogram name
2553 -- Check suspicious use of fat C pointer
2557 then
2558 Error_Msg_N
2560 Formal);
2562 -- Check suspicious return of boolean
2569 then
2571 Error_Msg_N
2575 -- Check suspicious tagged type
2579 and then
2580 Is_Tagged_Type
2583 then
2584 Error_Msg_N
2588 -- Check wrong convention subprogram pointer
2592 then
2593 Error_Msg_N
2597 Error_Msg_NE
2602 -- Turn off name qualification after message output
2607 -- Check for unconstrained array in exported foreign
2608 -- convention case.
2614 and then Warn_On_Export_Import
2616 -- Exclude VM case, since both .NET and JVM can handle
2617 -- unconstrained arrays without a problem.
2620 then
2623 -- If this is an inherited operation, place the
2624 -- warning on the derived type declaration, rather
2625 -- than on the original subprogram.
2628 N_Full_Type_Declaration
2629 then
2633 Error_Msg_NE
2636 else
2640 Error_Msg_NE
2643 Error_Msg_NE
2654 -- If the formal is an anonymous_access_to_subprogram
2655 -- freeze the subprogram type as well, to prevent
2656 -- scope anomalies in gigi, because there is no other
2657 -- clear point at which it could be frozen.
2661 then
2669 -- Case of function: similar checks on return type
2673 -- Freeze return type
2677 -- AI05-0151: the return type may have been incomplete
2678 -- at the point of declaration.
2682 then
2689 -- Check suspicious return type for C function
2691 if Warn_On_Export_Import
2693 or else
2696 then
2697 -- Check suspicious return of fat C pointer
2703 then
2704 Error_Msg_N
2708 -- Check suspicious return of boolean
2716 then
2717 declare
2720 begin
2721 Error_Msg_NE
2724 Error_Msg_NE
2729 -- Check suspicious return tagged type
2733 and then
2734 Is_Tagged_Type
2739 then
2740 Error_Msg_N
2744 -- Check return of wrong convention subprogram pointer
2750 then
2751 Error_Msg_N
2755 Error_Msg_NE
2761 -- Give warning for suspicious return of a result of an
2762 -- unconstrained array type in a foreign convention
2763 -- function.
2767 -- We are looking for a return of unconstrained array
2772 -- Exclude imported routines, the warning does not
2773 -- belong on the import, but rather on the routine
2774 -- definition.
2778 -- Exclude VM case, since both .NET and JVM can handle
2779 -- return of unconstrained arrays without a problem.
2783 -- Check that general warning is enabled, and that it
2784 -- is not suppressed for this particular case.
2786 and then Warn_On_Export_Import
2789 then
2790 Error_Msg_N
2798 -- Must freeze its parent first if it is a derived subprogram
2804 -- We don't freeze internal subprograms, because we don't normally
2805 -- want addition of extra formals or mechanism setting to happen
2806 -- for those. However we do pass through predefined dispatching
2807 -- cases, since extra formals may be needed in some cases, such as
2808 -- for the stream 'Input function (build-in-place formals).
2812 then
2816 -- Here for other than a subprogram or type
2818 else
2819 -- If entity has a type, and it is not a generic unit, then
2820 -- freeze it first (RM 13.14(10)).
2824 then
2828 -- Special processing for objects created by object declaration
2832 -- Abstract type allowed only for C++ imported variables or
2833 -- constants.
2835 -- Note: we inhibit this check for objects that do not come
2836 -- from source because there is at least one case (the
2837 -- expansion of x'Class'Input where x is abstract) where we
2838 -- legitimately generate an abstract object.
2844 then
2849 Error_Msg_NE
2855 -- For object created by object declaration, perform required
2856 -- categorization (preelaborate and pure) checks. Defer these
2857 -- checks to freeze time since pragma Import inhibits default
2858 -- initialization and thus pragma Import affects these checks.
2862 -- If there is an address clause, check that it is valid
2866 -- If the object needs any kind of default initialization, an
2867 -- error must be issued if No_Default_Initialization applies.
2868 -- The check doesn't apply to imported objects, which are not
2869 -- ever default initialized, and is why the check is deferred
2870 -- until freezing, at which point we know if Import applies.
2871 -- Deferred constants are also exempted from this test because
2872 -- their completion is explicit, or through an import pragma.
2876 then
2882 and then
2887 or else
2890 then
2892 Check_Restriction
2896 -- Check that a Thread_Local_Storage variable does not have
2897 -- default initialization, and any explicit initialization must
2898 -- either be the null constant or a static constant.
2901 declare
2903 begin
2904 if Has_Default_Initialization
2905 or else
2907 and then
2909 or else not
2911 or else
2913 then
2914 Error_Msg_NE
2917 Error_Msg_NE
2924 -- For imported objects, set Is_Public unless there is also an
2925 -- address clause, which means that there is no external symbol
2926 -- needed for the Import (Is_Public may still be set for other
2927 -- unrelated reasons). Note that we delayed this processing
2928 -- till freeze time so that we can be sure not to set the flag
2929 -- if there is an address clause. If there is such a clause,
2930 -- then the only purpose of the Import pragma is to suppress
2931 -- implicit initialization.
2935 then
2939 -- For convention C objects of an enumeration type, warn if
2940 -- the size is not integer size and no explicit size given.
2941 -- Skip warning for Boolean, and Character, assume programmer
2942 -- expects 8-bit sizes for these cases.
2945 or else
2952 then
2954 Error_Msg_N
2956 E);
2961 -- Check that a constant which has a pragma Volatile[_Components]
2962 -- or Atomic[_Components] also has a pragma Import (RM C.6(13)).
2964 -- Note: Atomic[_Components] also sets Volatile[_Components]
2969 then
2970 -- Make sure we actually have a pragma, and have not merely
2971 -- inherited the indication from elsewhere (e.g. an address
2972 -- clause, which is not good enough in RM terms!)
2975 or else
2977 then
2978 Error_Msg_N
2983 or else
2985 then
2986 Error_Msg_N
2992 -- Static objects require special handling
2996 then
3000 -- Remaining step is to layout objects
3003 or else
3005 or else
3007 or else
3009 then
3014 -- Case of a type or subtype being frozen
3016 else
3017 -- We used to check here that a full type must have preelaborable
3018 -- initialization if it completes a private type specified with
3019 -- pragma Preelaborable_Initialization, but that missed cases where
3020 -- the types occur within a generic package, since the freezing
3021 -- that occurs within a containing scope generally skips traversal
3022 -- of a generic unit's declarations (those will be frozen within
3023 -- instances). This check was moved to Analyze_Package_Specification.
3025 -- The type may be defined in a generic unit. This can occur when
3026 -- freezing a generic function that returns the type (which is
3027 -- defined in a parent unit). It is clearly meaningless to freeze
3028 -- this type. However, if it is a subtype, its size may be determi-
3029 -- nable and used in subsequent checks, so might as well try to
3030 -- compute it.
3034 then
3039 -- Deal with special cases of freezing for subtype
3043 -- Before we do anything else, a specialized test for the case of
3044 -- a size given for an array where the array needs to be packed,
3045 -- but was not so the size cannot be honored. This would of course
3046 -- be caught by the backend, and indeed we don't catch all cases.
3047 -- The point is that we can give a better error message in those
3048 -- cases that we do catch with the circuitry here. Also if pragma
3049 -- Implicit_Packing is set, this is where the packing occurs.
3051 -- The reason we do this so early is that the processing in the
3052 -- automatic packing case affects the layout of the base type, so
3053 -- it must be done before we freeze the base type.
3056 declare
3060 begin
3061 -- Check enabling conditions. These are straightforward
3062 -- except for the test for a limited composite type. This
3063 -- eliminates the rare case of a array of limited components
3064 -- where there are issues of whether or not we can go ahead
3065 -- and pack the array (since we can't freely pack and unpack
3066 -- arrays if they are limited).
3068 -- Note that we check the root type explicitly because the
3069 -- whole point is we are doing this test before we have had
3070 -- a chance to freeze the base type (and it is that freeze
3071 -- action that causes stuff to be inherited).
3084 then
3091 then
3092 declare
3102 -- What we are looking for here is the situation where
3103 -- the RM_Size given would be exactly right if there
3104 -- was a pragma Pack (resulting in the component size
3105 -- being the same as the RM_Size). Furthermore, the
3106 -- component type size must be an odd size (not a
3107 -- multiple of storage unit). If the component RM size
3108 -- is an exact number of storage units that is a power
3109 -- of two, the array is not packed and has a standard
3110 -- representation.
3112 begin
3115 then
3116 -- For implicit packing mode, just set the
3117 -- component size silently.
3125 -- Otherwise give an error message
3127 else
3128 Error_Msg_NE
3130 Error_Msg_N -- CODEFIX
3136 and then Implicit_Packing
3137 and then
3141 then
3143 -- Not a packed array, but indicate the desired
3144 -- component size, for the back-end.
3154 -- If ancestor subtype present, freeze that first. Note that this
3155 -- will also get the base type frozen. Need RM reference ???
3162 -- No ancestor subtype present
3164 else
3165 -- See if we have a nearest ancestor that has a predicate.
3166 -- That catches the case of derived type with a predicate.
3167 -- Need RM reference here ???
3175 -- Freeze base type before freezing the entity (RM 13.14(15))
3182 -- For a derived type, freeze its parent type first (RM 13.14(15))
3189 -- For array type, freeze index types and component type first
3190 -- before freezing the array (RM 13.14(15)).
3193 declare
3199 -- Set true if any of the index types is an enumeration type
3200 -- with a non-standard representation.
3202 begin
3211 then
3218 -- Processing that is done only for base types
3222 -- Propagate flags for component type
3226 then
3234 -- If packing was requested or if the component size was set
3235 -- explicitly, then see if bit packing is required. This
3236 -- processing is only done for base types, since all the
3237 -- representation aspects involved are type-related. This
3238 -- is not just an optimization, if we start processing the
3239 -- subtypes, they interfere with the settings on the base
3240 -- type (this is because Is_Packed has a slightly different
3241 -- meaning before and after freezing).
3243 declare
3247 begin
3251 then
3260 else
3263 -- We can set the component size if it is less than
3264 -- 16, rounding it up to the next storage unit size.
3270 else
3274 -- Set component size up to match alignment if it
3275 -- would otherwise be less than the alignment. This
3276 -- deals with cases of types whose alignment exceeds
3277 -- their size (padded types).
3280 declare
3282 begin
3290 -- Case of component size that may result in packing
3293 declare
3299 Get_Attribute_Definition_Clause
3301 begin
3302 -- Warn if we have pack and component size so that
3303 -- the pack is ignored.
3305 -- Note: here we must check for the presence of a
3306 -- component size before checking for a Pack pragma
3307 -- to deal with the case where the array type is a
3308 -- derived type whose parent is currently private.
3312 and then Warn_On_Redundant_Constructs
3313 then
3315 Error_Msg_NE
3318 Error_Msg_N
3320 Pack_Pragma);
3325 -- Set component size if not already set by a
3326 -- component size clause.
3332 -- Check for base type of 8, 16, 32 bits, where an
3333 -- unsigned subtype has a length one less than the
3334 -- base type (e.g. Natural subtype of Integer).
3336 -- In such cases, if a component size was not set
3337 -- explicitly, then generate a warning.
3341 and then
3344 then
3348 Error_Msg_N
3351 Error_Msg_N
3357 -- Actual packing is not needed for 8, 16, 32, 64.
3358 -- Also not needed for 24 if alignment is 1.
3365 then
3366 -- Here the array was requested to be packed,
3367 -- but the packing request had no effect, so
3368 -- Is_Packed is reset.
3370 -- Note: semantically this means that we lose
3371 -- track of the fact that a derived type
3372 -- inherited a pragma Pack that was non-
3373 -- effective, but that seems fine.
3375 -- We regard a Pack pragma as a request to set
3376 -- a representation characteristic, and this
3377 -- request may be ignored.
3384 then
3385 Set_Has_Non_Standard_Rep
3389 -- In all other cases, packing is indeed needed
3391 else
3400 -- Check for Atomic_Components or Aliased with unsuitable
3401 -- packing or explicit component size clause given.
3407 then
3411 -- Outputs error messages for incorrect CS clause or
3412 -- pragma Pack for aliased or atomic components (T is
3413 -- "aliased" or "atomic");
3415 -----------------
3416 -- Complain_CS --
3417 -----------------
3420 begin
3422 Clause :=
3423 Get_Attribute_Definition_Clause
3427 Error_Msg_N
3431 Error_Msg_N
3434 else
3435 Error_Msg_N
3440 else
3441 Error_Msg_N
3449 -- Start of processing for Alias_Atomic_Check
3451 begin
3453 -- If object size of component type isn't known, we
3454 -- cannot be sure so we defer to the back end.
3459 -- Case where component size has no effect. First
3460 -- check for object size of component type multiple
3461 -- of the storage unit size.
3465 -- OK in both packing case and component size case
3466 -- if RM size is known and static and the same as
3467 -- the object size.
3469 and then
3473 -- Or if we have an explicit component size
3474 -- clause and the component size and object size
3475 -- are equal.
3477 or else
3480 then
3485 then
3490 then
3496 -- Warn for case of atomic type
3502 then
3503 Error_Msg_NE
3508 Error_Msg_Sloc :=
3509 Sloc
3510 (Get_Attribute_Definition_Clause
3512 Error_Msg_N
3514 Clause);
3517 Error_Msg_Sloc :=
3519 Error_Msg_N
3524 -- Processing that is done only for subtypes
3526 else
3527 -- Acquire alignment from base type
3535 -- For bit-packed arrays, check the size
3538 declare
3544 begin
3545 -- It is not clear if it is possible to have no size
3546 -- clause at this stage, but it is not worth worrying
3547 -- about. Post error on the entity name in the size
3548 -- clause if present, else on the type entity itself.
3552 else
3558 -- If any of the index types was an enumeration type with a
3559 -- non-standard rep clause, then we indicate that the array
3560 -- type is always packed (even if it is not bit packed).
3569 -- If the array is packed, we must create the packed array
3570 -- type to be used to actually implement the type. This is
3571 -- only needed for real array types (not for string literal
3572 -- types, since they are present only for the front end).
3576 then
3580 -- Size information of packed array type is copied to the
3581 -- array type, since this is really the representation. But
3582 -- do not override explicit existing size values. If the
3583 -- ancestor subtype is constrained the packed_array_type
3584 -- will be inherited from it, but the size may have been
3585 -- provided already, and must not be overridden either.
3588 and then
3591 then
3601 -- For non-packed arrays set the alignment of the array to the
3602 -- alignment of the component type if it is unknown. Skip this
3603 -- in atomic case (atomic arrays may need larger alignments).
3612 then
3617 -- For a class-wide type, the corresponding specific type is
3618 -- frozen as well (RM 13.14(15))
3623 -- If the base type of the class-wide type is still incomplete,
3624 -- the class-wide remains unfrozen as well. This is legal when
3625 -- E is the formal of a primitive operation of some other type
3626 -- which is being frozen.
3633 -- If the Class_Wide_Type is an Itype (when type is the anonymous
3634 -- parent of a derived type) and it is a library-level entity,
3635 -- generate an itype reference for it. Otherwise, its first
3636 -- explicit reference may be in an inner scope, which will be
3637 -- rejected by the back-end.
3641 then
3642 declare
3645 begin
3651 -- The equivalent type associated with a class-wide subtype needs
3652 -- to be frozen to ensure that its layout is done.
3656 then
3660 -- For a record (sub)type, freeze all the component types (RM
3661 -- 13.14(15). We test for E_Record_(sub)Type here, rather than using
3662 -- Is_Record_Type, because we don't want to attempt the freeze for
3663 -- the case of a private type with record extension (we will do that
3664 -- later when the full type is frozen).
3668 then
3671 -- For a concurrent type, freeze corresponding record type. This
3672 -- does not correspond to any specific rule in the RM, but the
3673 -- record type is essentially part of the concurrent type.
3674 -- Freeze as well all local entities. This includes record types
3675 -- created for entry parameter blocks, and whatever local entities
3676 -- may appear in the private part.
3680 Freeze_And_Append
3692 then
3702 -- Private types are required to point to the same freeze node as
3703 -- their corresponding full views. The freeze node itself has to
3704 -- point to the partial view of the entity (because from the partial
3705 -- view, we can retrieve the full view, but not the reverse).
3706 -- However, in order to freeze correctly, we need to freeze the full
3707 -- view. If we are freezing at the end of a scope (or within the
3708 -- scope of the private type), the partial and full views will have
3709 -- been swapped, the full view appears first in the entity chain and
3710 -- the swapping mechanism ensures that the pointers are properly set
3711 -- (on scope exit).
3713 -- If we encounter the partial view before the full view (e.g. when
3714 -- freezing from another scope), we freeze the full view, and then
3715 -- set the pointers appropriately since we cannot rely on swapping to
3716 -- fix things up (subtypes in an outer scope might not get swapped).
3720 then
3721 -- The construction of the dispatch table associated with library
3722 -- level tagged types forces freezing of all the primitives of the
3723 -- type, which may cause premature freezing of the partial view.
3724 -- For example:
3726 -- package Pkg is
3727 -- type T is tagged private;
3728 -- type DT is new T with private;
3729 -- procedure Prim (X : in out T; Y : in out DT'Class);
3730 -- private
3731 -- type T is tagged null record;
3732 -- Obj : T;
3733 -- type DT is new T with null record;
3734 -- end;
3736 -- In this case the type will be frozen later by the usual
3737 -- mechanism: an object declaration, an instantiation, or the
3738 -- end of a declarative part.
3742 then
3746 -- Case of full view present
3750 -- If full view has already been frozen, then no further
3751 -- processing is required
3758 -- Otherwise freeze full view and patch the pointers so that
3759 -- the freeze node will elaborate both views in the back-end.
3761 else
3762 declare
3765 begin
3768 then
3769 Freeze_And_Append
3782 else
3783 -- {Incomplete,Private}_Subtypes with Full_Views
3784 -- constrained by discriminants.
3795 -- AI-117 requires that the convention of a partial view be the
3796 -- same as the convention of the full view. Note that this is a
3797 -- recognized breach of privacy, but it's essential for logical
3798 -- consistency of representation, and the lack of a rule in
3799 -- RM95 was an oversight.
3806 -- Size information is copied from the full view to the
3807 -- incomplete or private view for consistency.
3809 -- We skip this is the full view is not a type. This is very
3810 -- strange of course, and can only happen as a result of
3811 -- certain illegalities, such as a premature attempt to derive
3812 -- from an incomplete type.
3821 -- Case of no full view present. If entity is derived or subtype,
3822 -- it is safe to freeze, correctness depends on the frozen status
3823 -- of parent. Otherwise it is either premature usage, or a Taft
3824 -- amendment type, so diagnosis is at the point of use and the
3825 -- type might be frozen later.
3829 then
3832 else
3837 -- For access subprogram, freeze types of all formals, the return
3838 -- type was already frozen, since it is the Etype of the function.
3839 -- Formal types can be tagged Taft amendment types, but otherwise
3840 -- they cannot be incomplete.
3848 then
3852 -- AI05-151: Incomplete types are allowed in access to
3853 -- subprogram specifications.
3856 Error_Msg_NE
3867 -- For access to a protected subprogram, freeze the equivalent type
3868 -- (however this is not set if we are not generating code or if this
3869 -- is an anonymous type used just for resolution).
3877 -- Generic types are never seen by the back-end, and are also not
3878 -- processed by the expander (since the expander is turned off for
3879 -- generic processing), so we never need freeze nodes for them.
3885 -- Some special processing for non-generic types to complete
3886 -- representation details not known till the freeze point.
3891 -- Some error checks required for ordinary fixed-point type. Defer
3892 -- these till the freeze-point since we need the small and range
3893 -- values. We only do these checks for base types
3898 Error_Msg_N
3903 Error_Msg_N
3909 Error_Msg_N
3915 Error_Msg_N
3927 and then Warn_On_Suspicious_Modulus_Value
3928 then
3934 -- If a pragma Default_Storage_Pool applies, and this type has no
3935 -- Storage_Pool or Storage_Size clause (which must have occurred
3936 -- before the freezing point), then use the default. This applies
3937 -- only to base types.
3943 then
3944 -- Case of pragma Default_Storage_Pool (null)
3949 -- Case of pragma Default_Storage_Pool (storage_pool_NAME)
3951 else
3956 -- Check restriction for standard storage pool
3962 -- Deal with error message for pure access type. This is not an
3963 -- error in Ada 2005 if there is no pool (see AI-366).
3968 then
3972 Error_Msg_N
3976 Error_Msg_N
3979 else
3980 Error_Msg_N
3987 -- Case of composite types
3991 -- AI-117 requires that all new primitives of a tagged type must
3992 -- inherit the convention of the full view of the type. Inherited
3993 -- and overriding operations are defined to inherit the convention
3994 -- of their parent or overridden subprogram (also specified in
3995 -- AI-117), which will have occurred earlier (in Derive_Subprogram
3996 -- and New_Overloaded_Entity). Here we set the convention of
3997 -- primitives that are still convention Ada, which will ensure
3998 -- that any new primitives inherit the type's convention. Class-
3999 -- wide types can have a foreign convention inherited from their
4000 -- specific type, but are excluded from this since they don't have
4001 -- any associated primitives.
4006 then
4007 declare
4011 begin
4024 -- Now that all types from which E may depend are frozen, see if the
4025 -- size is known at compile time, if it must be unsigned, or if
4026 -- strict alignment is required
4035 -- Do not allow a size clause for a type which does not have a size
4036 -- that is known at compile time
4040 then
4041 -- Suppress this message if errors posted on E, even if we are
4042 -- in all errors mode, since this is often a junk message
4045 Error_Msg_N
4051 -- Now we set/verify the representation information, in particular
4052 -- the size and alignment values. This processing is not required for
4053 -- generic types, since generic types do not play any part in code
4054 -- generation, and so the size and alignment values for such types
4055 -- are irrelevant.
4060 -- Otherwise we call the layout procedure
4062 else
4066 -- If the type has a Defaut_Value/Default_Component_Value aspect,
4067 -- this is where we analye the expression (after the type is frozen,
4068 -- since in the case of Default_Value, we are analyzing with the
4069 -- type itself, and we treat Default_Component_Value similarly for
4070 -- the sake of uniformity.
4073 declare
4079 begin
4083 else
4095 Flag_Non_Static_Expr
4102 -- End of freeze processing for type entities
4105 -- Here is where we logically freeze the current entity. If it has a
4106 -- freeze node, then this is the point at which the freeze node is
4107 -- linked into the result list.
4111 -- If a freeze node is already allocated, use it, otherwise allocate
4112 -- a new one. The preallocation happens in the case of anonymous base
4113 -- types, where we preallocate so that we can set First_Subtype_Link.
4114 -- Note that we reset the Sloc to the current freeze location.
4120 else
4131 -- A final pass over record types with discriminants. If the type
4132 -- has an incomplete declaration, there may be constrained access
4133 -- subtypes declared elsewhere, which do not depend on the discrimi-
4134 -- nants of the type, and which are used as component types (i.e.
4135 -- the full view is a recursive type). The designated types of these
4136 -- subtypes can only be elaborated after the type itself, and they
4137 -- need an itype reference.
4141 then
4142 declare
4147 begin
4157 then
4169 -- When a type is frozen, the first subtype of the type is frozen as
4170 -- well (RM 13.14(15)). This has to be done after freezing the type,
4171 -- since obviously the first subtype depends on its own base type.
4176 -- If we just froze a tagged non-class wide record, then freeze the
4177 -- corresponding class-wide type. This must be done after the tagged
4178 -- type itself is frozen, because the class-wide type refers to the
4179 -- tagged type which generates the class.
4184 then
4191 -- Special handling for subprograms
4195 -- If subprogram has address clause then reset Is_Public flag, since
4196 -- we do not want the backend to generate external references.
4200 then
4203 -- If no address clause and not intrinsic, then for imported
4204 -- subprogram in main unit, generate descriptor if we are in
4205 -- Propagate_Exceptions mode.
4207 -- This is very odd code, it makes a null result, why ???
4209 elsif Propagate_Exceptions
4213 then
4223 -----------------------------
4224 -- Freeze_Enumeration_Type --
4225 -----------------------------
4228 begin
4229 -- By default, if no size clause is present, an enumeration type with
4230 -- Convention C is assumed to interface to a C enum, and has integer
4231 -- size. This applies to types. For subtypes, verify that its base
4232 -- type has no size clause either.
4238 then
4241 else
4242 -- If the enumeration type interfaces to C, and it has a size clause
4243 -- that specifies less than int size, it warrants a warning. The
4244 -- user may intend the C type to be an enum or a char, so this is
4245 -- not by itself an error that the Ada compiler can detect, but it
4246 -- it is a worth a heads-up. For Boolean and Character types we
4247 -- assume that the programmer has the proper C type in mind.
4254 then
4255 Error_Msg_N
4263 -----------------------
4264 -- Freeze_Expression --
4265 -----------------------
4276 -- This flag is set true if the entity must be frozen outside the
4277 -- current subprogram. This happens in the case of expander generated
4278 -- subprograms (_Init_Proc, _Input, _Output, _Read, _Write) which do
4279 -- not freeze all entities like other bodies, but which nevertheless
4280 -- may reference entities that have to be frozen before the body and
4281 -- obviously cannot be frozen inside the body.
4284 -- Given an N_Handled_Sequence_Of_Statements node N, determines whether
4285 -- it is the handled statement sequence of an expander-generated
4286 -- subprogram (init proc, stream subprogram, or renaming as body).
4287 -- If so, this is not a freezing context.
4289 -----------------
4290 -- In_Exp_Body --
4291 -----------------
4297 begin
4300 else
4307 else
4317 N_Subprogram_Renaming_Declaration)
4318 then
4320 else
4326 -- Start of processing for Freeze_Expression
4328 begin
4329 -- Immediate return if freezing is inhibited. This flag is set by the
4330 -- analyzer to stop freezing on generated expressions that would cause
4331 -- freezing if they were in the source program, but which are not
4332 -- supposed to freeze, since they are created.
4338 -- If expression is non-static, then it does not freeze in a default
4339 -- expression, see section "Handling of Default Expressions" in the
4340 -- spec of package Sem for further details. Note that we have to
4341 -- make sure that we actually have a real expression (if we have
4342 -- a subtype indication, we can't test Is_Static_Expression!)
4344 if In_Spec_Exp
4347 then
4351 -- Freeze type of expression if not frozen already
4359 -- Base type may be an derived numeric type that is frozen at
4360 -- the point of declaration, but first_subtype is still unfrozen.
4367 -- For entity name, freeze entity if not frozen already. A special
4368 -- exception occurs for an identifier that did not come from source.
4369 -- We don't let such identifiers freeze a non-internal entity, i.e.
4370 -- an entity that did come from source, since such an identifier was
4371 -- generated by the expander, and cannot have any semantic effect on
4372 -- the freezing semantics. For example, this stops the parameter of
4373 -- an initialization procedure from freezing the variable.
4380 then
4382 else
4386 -- For an allocator freeze designated type if not frozen already
4388 -- For an aggregate whose component type is an access type, freeze the
4389 -- designated type now, so that its freeze does not appear within the
4390 -- loop that might be created in the expansion of the aggregate. If the
4391 -- designated type is a private type without full view, the expression
4392 -- cannot contain an allocator, so the type is not frozen.
4394 -- For a function, we freeze the entity when the subprogram declaration
4395 -- is frozen, but a function call may appear in an initialization proc.
4396 -- before the declaration is frozen. We need to generate the extra
4397 -- formals, if any, to ensure that the expansion of the call includes
4398 -- the proper actuals. This only applies to Ada subprograms, not to
4399 -- imported ones.
4410 then
4414 when N_Selected_Component |
4415 N_Indexed_Component |
4416 N_Slice =>
4427 then
4438 then
4442 -- All done if nothing needs freezing
4447 then
4451 -- Loop for looking at the right place to insert the freeze nodes,
4452 -- exiting from the loop when it is appropriate to insert the freeze
4453 -- node before the current node P.
4455 -- Also checks some special exceptions to the freezing rules. These
4456 -- cases result in a direct return, bypassing the freeze action.
4459 loop
4462 -- If we don't have a parent, then we are not in a well-formed tree.
4463 -- This is an unusual case, but there are some legitimate situations
4464 -- in which this occurs, notably when the expressions in the range of
4465 -- a type declaration are resolved. We simply ignore the freeze
4466 -- request in this case. Is this right ???
4472 -- See if we have got to an appropriate point in the tree
4476 -- A special test for the exception of (RM 13.14(8)) for the case
4477 -- of per-object expressions (RM 3.8(18)) occurring in component
4478 -- definition or a discrete subtype definition. Note that we test
4479 -- for a component declaration which includes both cases we are
4480 -- interested in, and furthermore the tree does not have explicit
4481 -- nodes for either of these two constructs.
4485 -- The case we want to test for here is an identifier that is
4486 -- a per-object expression, this is either a discriminant that
4487 -- appears in a context other than the component declaration
4488 -- or it is a reference to the type of the enclosing construct.
4490 -- For either of these cases, we skip the freezing
4492 if not In_Spec_Expression
4495 then
4496 -- We recognize the discriminant case by just looking for
4497 -- a reference to a discriminant. It can only be one for
4498 -- the enclosing construct. Skip freezing in this case.
4503 -- For the case of a reference to the enclosing record,
4504 -- (or task or protected type), we look for a type that
4505 -- matches the current scope.
4512 -- If we have an enumeration literal that appears as the choice in
4513 -- the aggregate of an enumeration representation clause, then
4514 -- freezing does not occur (RM 13.14(10)).
4518 -- The case we are looking for is an enumeration literal
4522 then
4523 -- If enumeration literal appears directly as the choice,
4524 -- do not freeze (this is the normal non-overloaded case)
4528 then
4531 -- If enumeration literal appears as the name of function
4532 -- which is the choice, then also do not freeze. This
4533 -- happens in the overloaded literal case, where the
4534 -- enumeration literal is temporarily changed to a function
4535 -- call for overloading analysis purposes.
4538 and then
4540 and then
4542 then
4547 -- Normally if the parent is a handled sequence of statements,
4548 -- then the current node must be a statement, and that is an
4549 -- appropriate place to insert a freeze node.
4553 -- An exception occurs when the sequence of statements is for
4554 -- an expander generated body that did not do the usual freeze
4555 -- all operation. In this case we usually want to freeze
4556 -- outside this body, not inside it, and we skip past the
4557 -- subprogram body that we are inside.
4561 -- However, we *do* want to freeze at this point if we have
4562 -- an entity to freeze, and that entity is declared *inside*
4563 -- the body of the expander generated procedure. This case
4564 -- is recognized by the scope of the type, which is either
4565 -- the spec for some enclosing body, or (in the case of
4566 -- init_procs, for which there are no separate specs) the
4567 -- current scope.
4569 declare
4573 begin
4578 or else
4580 then
4586 then
4592 -- If not that exception to the exception, then this is
4593 -- where we delay the freeze till outside the body.
4598 -- Here if normal case where we are in handled statement
4599 -- sequence and want to do the insertion right there.
4601 else
4605 -- If parent is a body or a spec or a block, then the current node
4606 -- is a statement or declaration and we can insert the freeze node
4607 -- before it.
4609 when N_Block_Statement |
4610 N_Entry_Body |
4611 N_Package_Body |
4612 N_Package_Specification |
4613 N_Protected_Body |
4614 N_Subprogram_Body |
4617 -- The expander is allowed to define types in any statements list,
4618 -- so any of the following parent nodes also mark a freezing point
4619 -- if the actual node is in a list of statements or declarations.
4621 when N_Abortable_Part |
4622 N_Accept_Alternative |
4623 N_And_Then |
4624 N_Case_Statement_Alternative |
4625 N_Compilation_Unit_Aux |
4626 N_Conditional_Entry_Call |
4627 N_Delay_Alternative |
4628 N_Elsif_Part |
4629 N_Entry_Call_Alternative |
4630 N_Exception_Handler |
4631 N_Extended_Return_Statement |
4632 N_Freeze_Entity |
4633 N_If_Statement |
4634 N_Or_Else |
4635 N_Selective_Accept |
4636 N_Triggering_Alternative =>
4640 -- Note: The N_Loop_Statement is a special case. A type that
4641 -- appears in the source can never be frozen in a loop (this
4642 -- occurs only because of a loop expanded by the expander), so we
4643 -- keep on going. Otherwise we terminate the search. Same is true
4644 -- of any entity which comes from source. (if they have predefined
4645 -- type, that type does not appear to come from source, but the
4646 -- entity should not be frozen here).
4652 -- For all other cases, keep looking at parents
4658 -- We fall through the case if we did not yet find the proper
4659 -- place in the free for inserting the freeze node, so climb!
4664 -- If the expression appears in a record or an initialization procedure,
4665 -- the freeze nodes are collected and attached to the current scope, to
4666 -- be inserted and analyzed on exit from the scope, to insure that
4667 -- generated entities appear in the correct scope. If the expression is
4668 -- a default for a discriminant specification, the scope is still void.
4669 -- The expression can also appear in the discriminant part of a private
4670 -- or concurrent type.
4672 -- If the expression appears in a constrained subcomponent of an
4673 -- enclosing record declaration, the freeze nodes must be attached to
4674 -- the outer record type so they can eventually be placed in the
4675 -- enclosing declaration list.
4677 -- The other case requiring this special handling is if we are in a
4678 -- default expression, since in that case we are about to freeze a
4679 -- static type, and the freeze scope needs to be the outer scope, not
4680 -- the scope of the subprogram with the default parameter.
4682 -- For default expressions and other spec expressions in generic units,
4683 -- the Move_Freeze_Nodes mechanism (see sem_ch12.adb) takes care of
4684 -- placing them at the proper place, after the generic unit.
4687 or else Freeze_Outside
4692 then
4693 declare
4698 begin
4711 -- The current scope may be that of a constrained component of
4712 -- an enclosing record declaration, which is above the current
4713 -- scope in the scope stack.
4714 -- If the expression is within a top-level pragma, as for a pre-
4715 -- condition on a library-level subprogram, nothing to do.
4719 then
4726 Freeze_Nodes;
4727 else
4737 -- Now we have the right place to do the freezing. First, a special
4738 -- adjustment, if we are in spec-expression analysis mode, these freeze
4739 -- actions must not be thrown away (normally all inserted actions are
4740 -- thrown away in this mode. However, the freeze actions are from static
4741 -- expressions and one of the important reasons we are doing this
4742 -- special analysis is to get these freeze actions. Therefore we turn
4743 -- off the In_Spec_Expression mode to propagate these freeze actions.
4744 -- This also means they get properly analyzed and expanded.
4748 -- Freeze the designated type of an allocator (RM 13.14(13))
4754 -- Freeze type of expression (RM 13.14(10)). Note that we took care of
4755 -- the enumeration representation clause exception in the loop above.
4761 -- Freeze name if one is present (RM 13.14(11))
4767 -- Restore In_Spec_Expression flag
4772 -----------------------------
4773 -- Freeze_Fixed_Point_Type --
4774 -----------------------------
4776 -- Certain fixed-point types and subtypes, including implicit base types
4777 -- and declared first subtypes, have not yet set up a range. This is
4778 -- because the range cannot be set until the Small and Size values are
4779 -- known, and these are not known till the type is frozen.
4781 -- To signal this case, Scalar_Range contains an unanalyzed syntactic range
4782 -- whose bounds are unanalyzed real literals. This routine will recognize
4783 -- this case, and transform this range node into a properly typed range
4784 -- with properly analyzed and resolved values.
4802 -- Returns size of type with given bounds. Also leaves these
4803 -- bounds set as the current bounds of the Typ.
4805 -----------
4806 -- Fsize --
4807 -----------
4810 begin
4816 -- Start of processing for Freeze_Fixed_Point_Type
4818 begin
4819 -- If Esize of a subtype has not previously been set, set it now
4826 else
4831 -- Immediate return if the range is already analyzed. This means that
4832 -- the range is already set, and does not need to be computed by this
4833 -- routine.
4839 -- Immediate return if either of the bounds raises Constraint_Error
4843 then
4850 -- Ordinary fixed-point case
4854 -- For the ordinary fixed-point case, we are allowed to fudge the
4855 -- end-points up or down by small. Generally we prefer to fudge up,
4856 -- i.e. widen the bounds for non-model numbers so that the end points
4857 -- are included. However there are cases in which this cannot be
4858 -- done, and indeed cases in which we may need to narrow the bounds.
4859 -- The following circuit makes the decision.
4861 -- Note: our terminology here is that Incl_EP means that the bounds
4862 -- are widened by Small if necessary to include the end points, and
4863 -- Excl_EP means that the bounds are narrowed by Small to exclude the
4864 -- end-points if this reduces the size.
4866 -- Note that in the Incl case, all we care about is including the
4867 -- end-points. In the Excl case, we want to narrow the bounds as
4868 -- much as permitted by the RM, to give the smallest possible size.
4885 begin
4886 -- First step. Base types are required to be symmetrical. Right
4887 -- now, the base type range is a copy of the first subtype range.
4888 -- This will be corrected before we are done, but right away we
4889 -- need to deal with the case where both bounds are non-negative.
4890 -- In this case, we set the low bound to the negative of the high
4891 -- bound, to make sure that the size is computed to include the
4892 -- required sign. Note that we do not need to worry about the
4893 -- case of both bounds negative, because the sign will be dealt
4894 -- with anyway. Furthermore we can't just go making such a bound
4895 -- symmetrical, since in a twos-complement system, there is an
4896 -- extra negative value which could not be accommodated on the
4897 -- positive side.
4902 then
4907 -- Compute the fudged bounds. If the number is a model number,
4908 -- then we do nothing to include it, but we are allowed to backoff
4909 -- to the next adjacent model number when we exclude it. If it is
4910 -- not a model number then we straddle the two values with the
4911 -- model numbers on either side.
4917 else
4921 -- The low value excluding the end point is Small greater, but
4922 -- we do not do this exclusion if the low value is positive,
4923 -- since it can't help the size and could actually hurt by
4924 -- crossing the high bound.
4929 -- If the value went from negative to zero, then we have the
4930 -- case where Loval_Incl_EP is the model number just below
4931 -- zero, so we want to stick to the negative value for the
4932 -- base type to maintain the condition that the size will
4933 -- include signed values.
4937 then
4941 else
4945 -- Similar processing for upper bound and high value
4951 else
4957 else
4961 -- One further adjustment is needed. In the case of subtypes, we
4962 -- cannot go outside the range of the base type, or we get
4963 -- peculiarities, and the base type range is already set. This
4964 -- only applies to the Incl values, since clearly the Excl values
4965 -- are already as restricted as they are allowed to be.
4972 -- Get size including and excluding end points
4977 -- No need to exclude end-points if it does not reduce size
4987 -- Now we set the actual size to be used. We want to use the
4988 -- bounds fudged up to include the end-points but only if this
4989 -- can be done without violating a specifically given size
4990 -- size clause or causing an unacceptable increase in size.
4992 -- Case of size clause given
4996 -- Use the inclusive size only if it is consistent with
4997 -- the explicitly specified size.
5004 -- If the inclusive size is too large, we try excluding
5005 -- the end-points (will be caught later if does not work).
5007 else
5013 -- Case of size clause not given
5015 else
5016 -- If we have a base type whose corresponding first subtype
5017 -- has an explicit size that is large enough to include our
5018 -- end-points, then do so. There is no point in working hard
5019 -- to get a base type whose size is smaller than the specified
5020 -- size of the first subtype.
5026 then
5031 -- If excluding the end-points makes the size smaller and
5032 -- results in a size of 8,16,32,64, then we take the smaller
5033 -- size. For the 64 case, this is compulsory. For the other
5034 -- cases, it seems reasonable. We like to include end points
5035 -- if we can, but not at the expense of moving to the next
5036 -- natural boundary of size.
5040 then
5045 -- Otherwise we can definitely include the end points
5047 else
5053 -- One pathological case: normally we never fudge a low bound
5054 -- down, since it would seem to increase the size (if it has
5055 -- any effect), but for ranges containing single value, or no
5056 -- values, the high bound can be small too large. Consider:
5058 -- type t is delta 2.0**(-14)
5059 -- range 131072.0 .. 0;
5061 -- That lower bound is *just* outside the range of 32 bits, and
5062 -- does need fudging down in this case. Note that the bounds
5063 -- will always have crossed here, since the high bound will be
5064 -- fudged down if necessary, as in the case of:
5066 -- type t is delta 2.0**(-14)
5067 -- range 131072.0 .. 131072.0;
5069 -- So we detect the situation by looking for crossed bounds,
5070 -- and if the bounds are crossed, and the low bound is greater
5071 -- than zero, we will always back it off by small, since this
5072 -- is completely harmless.
5079 -- And of course, we need to do exactly the same parallel
5080 -- fudge for flat ranges in the negative region.
5093 -- For the decimal case, none of this fudging is required, since there
5094 -- are no end-point problems in the decimal case (the end-points are
5095 -- always included).
5097 else
5101 -- At this stage, the actual size has been calculated and the proper
5102 -- required bounds are stored in the low and high bounds.
5106 Error_Msg_N
5108 Typ);
5112 -- Check size against explicit given size
5118 Error_Msg_NE
5122 else
5126 -- Increase size to next natural boundary if no size clause given
5128 else
5135 else
5143 -- If we have a base type, then expand the bounds so that they extend to
5144 -- the full width of the allocated size in bits, to avoid junk range
5145 -- checks on intermediate computations.
5152 -- Final step is to reanalyze the bounds using the proper type
5153 -- and set the Corresponding_Integer_Value fields of the literals.
5159 -- Resolve with universal fixed if the base type, and the base type if
5160 -- it is a subtype. Note we can't resolve the base type with itself,
5161 -- that would be a reference before definition.
5165 else
5169 -- Set corresponding integer value for bound
5171 Set_Corresponding_Integer_Value
5174 -- Similar processing for high bound
5182 else
5186 Set_Corresponding_Integer_Value
5189 -- Set type of range to correspond to bounds
5193 -- Set Esize to calculated size if not set already
5199 -- Set RM_Size if not already set. If already set, check value
5201 declare
5204 begin
5209 Error_Msg_NE
5214 else
5220 ------------------
5221 -- Freeze_Itype --
5222 ------------------
5227 begin
5236 --------------------------
5237 -- Freeze_Static_Object --
5238 --------------------------
5243 -- Exception raised if the type of a static object cannot be made
5244 -- static. This happens if the type depends on non-global objects.
5247 -- Called to ensure that an expression used as part of a type definition
5248 -- is statically allocatable, which means that the expression type is
5249 -- statically allocatable, and the expression is either static, or a
5250 -- reference to a library level constant.
5253 -- Called to mark a type as static, checking that it is possible
5254 -- to set the type as static. If it is not possible, then the
5255 -- exception Cannot_Be_Static is raised.
5257 -----------------------------
5258 -- Ensure_Expression_Is_SA --
5259 -----------------------------
5264 begin
5276 then
5284 -----------------------
5285 -- Ensure_Type_Is_SA --
5286 -----------------------
5292 begin
5293 -- If type is library level, we are all set
5299 -- We are also OK if the type already marked as statically allocated,
5300 -- which means we processed it before.
5306 -- Mark type as statically allocated
5310 -- Check that it is safe to statically allocate this type
5328 declare
5332 begin
5344 else
5353 then
5372 else
5377 -- Start of processing for Freeze_Static_Object
5379 begin
5382 exception
5385 -- If the object that cannot be static is imported or exported, then
5386 -- issue an error message saying that this object cannot be imported
5387 -- or exported. If it has an address clause it is an overlay in the
5388 -- current partition and the static requirement is not relevant.
5389 -- Do not issue any error message when ignoring rep clauses.
5396 Error_Msg_N
5400 -- Otherwise must be exported, something is wrong if compiler
5401 -- is marking something as statically allocated which cannot be).
5404 Error_Msg_N
5409 -----------------------
5410 -- Freeze_Subprogram --
5411 -----------------------
5417 begin
5418 -- Subprogram may not have an address clause unless it is imported
5422 Error_Msg_N
5429 -- Reset the Pure indication on an imported subprogram unless an
5430 -- explicit Pure_Function pragma was present. We do this because
5431 -- otherwise it is an insidious error to call a non-pure function from
5432 -- pure unit and have calls mysteriously optimized away. What happens
5433 -- here is that the Import can bypass the normal check to ensure that
5434 -- pure units call only pure subprograms.
5439 then
5443 -- For non-foreign convention subprograms, this is where we create
5444 -- the extra formals (for accessibility level and constrained bit
5445 -- information). We delay this till the freeze point precisely so
5446 -- that we know the convention!
5452 -- If this is convention Ada and a Valued_Procedure, that's odd
5457 and then Warn_On_Export_Import
5458 then
5459 Error_Msg_N
5464 -- Case of foreign convention
5466 else
5469 -- For foreign conventions, warn about return of an
5470 -- unconstrained array.
5472 -- Note: we *do* allow a return by descriptor for the VMS case,
5473 -- though here there is probably more to be done ???
5478 -- If no return type, probably some other error, e.g. a
5479 -- missing full declaration, so ignore.
5484 -- If the return type is generic, we have emitted a warning
5485 -- earlier on, and there is nothing else to check here. Specific
5486 -- instantiations may lead to erroneous behavior.
5491 -- Display warning if returning unconstrained array
5496 -- Exclude cases where descriptor mechanism is set, since the
5497 -- VMS descriptor mechanisms allow such unconstrained returns.
5501 -- Check appropriate warning is enabled (should we check for
5502 -- Warnings (Off) on specific entities here, probably so???)
5504 and then Warn_On_Export_Import
5506 -- Exclude the VM case, since return of unconstrained arrays
5507 -- is properly handled in both the JVM and .NET cases.
5510 then
5511 Error_Msg_N
5518 -- If any of the formals for an exported foreign convention
5519 -- subprogram have defaults, then emit an appropriate warning since
5520 -- this is odd (default cannot be used from non-Ada code)
5525 if Warn_On_Export_Import
5527 then
5528 Error_Msg_N
5538 -- For VMS, descriptor mechanisms for parameters are allowed only for
5539 -- imported/exported subprograms. Moreover, the NCA descriptor is not
5540 -- allowed for parameters of exported subprograms.
5547 Error_Msg_N
5549 Error_Msg_N
5560 Error_Msg_N
5562 Error_Msg_N
5571 -- Pragma Inline_Always is disallowed for dispatching subprograms
5572 -- because the address of such subprograms is saved in the dispatch
5573 -- table to support dispatching calls, and dispatching calls cannot
5574 -- be inlined. This is consistent with the restriction against using
5575 -- 'Access or 'Address on an Inline_Always subprogram.
5579 then
5580 Error_Msg_N
5584 -- Because of the implicit representation of inherited predefined
5585 -- operators in the front-end, the overriding status of the operation
5586 -- may be affected when a full view of a type is analyzed, and this is
5587 -- not captured by the analysis of the corresponding type declaration.
5588 -- Therefore the correctness of a not-overriding indicator must be
5589 -- rechecked when the subprogram is frozen.
5593 then
5598 ----------------------
5599 -- Is_Fully_Defined --
5600 ----------------------
5603 begin
5612 then
5613 -- Verify that the record type has no components with private types
5614 -- without completion.
5616 declare
5619 begin
5631 -- For the designated type of an access to subprogram, all types in
5632 -- the profile must be fully defined.
5635 declare
5638 begin
5651 else
5657 ---------------------------------
5658 -- Process_Default_Expressions --
5659 ---------------------------------
5661 procedure Process_Default_Expressions
5664 is
5671 begin
5674 -- A subprogram instance and its associated anonymous subprogram share
5675 -- their signature. The default expression functions are defined in the
5676 -- wrapper packages for the anonymous subprogram, and should not be
5677 -- generated again for the instance.
5682 then
5690 -- We work with a copy of the default expression because we
5691 -- do not want to disturb the original, since this would mess
5692 -- up the conformance checking.
5696 -- The analysis of the expression may generate insert actions,
5697 -- which of course must not be executed. We wrap those actions
5698 -- in a procedure that is not called, and later on eliminated.
5699 -- The following cases have no side-effects, and are analyzed
5700 -- directly.
5711 and then
5713 then
5715 -- If there is no default function, we must still do a full
5716 -- analyze call on the default value, to ensure that all error
5717 -- checks are performed, e.g. those associated with static
5718 -- evaluation. Note: this branch will always be taken if the
5719 -- analyzer is turned off (but we still need the error checks).
5721 -- Note: the setting of parent here is to meet the requirement
5722 -- that we can only analyze the expression while attached to
5723 -- the tree. Really the requirement is that the parent chain
5724 -- be set, we don't actually need to be in the tree.
5729 -- Default expressions are resolved with their own type if the
5730 -- context is generic, to avoid anomalies with private types.
5734 else
5738 -- If that resolved expression will raise constraint error,
5739 -- then flag the default value as raising constraint error.
5740 -- This allows a proper error message on the calls.
5746 -- If the default is a parameterless call, we use the name of
5747 -- the called function directly, and there is no body to build.
5751 then
5754 -- Else construct and analyze the body of a wrapper procedure
5755 -- that contains an object declaration to hold the expression.
5756 -- Given that this is done only to complete the analysis, it
5757 -- simpler to build a procedure than a function which might
5758 -- involve secondary stack expansion.
5760 else
5763 Dbody :=
5765 Specification =>
5772 Object_Definition =>
5776 Handled_Statement_Sequence =>
5793 ----------------------------------------
5794 -- Set_Component_Alignment_If_Not_Set --
5795 ----------------------------------------
5798 begin
5799 -- Ignore if not base type, subtypes don't need anything
5805 -- Do not override existing representation
5816 else
5817 Set_Component_Alignment
5823 ------------------
5824 -- Undelay_Type --
5825 ------------------
5828 begin
5832 -- Since we don't want T to have a Freeze_Node, we don't want its
5833 -- Full_View or Corresponding_Record_Type to have one either.
5835 -- ??? Fundamentally, this whole handling is a kludge. What we really
5836 -- want is to be sure that for an Itype that's part of record R and is a
5837 -- subtype of type T, that it's frozen after the later of the freeze
5838 -- points of R and T. We have no way of doing that directly, so what we
5839 -- do is force most such Itypes to be frozen as part of freezing R via
5840 -- this procedure and only delay the ones that need to be delayed
5841 -- (mostly the designated types of access types that are defined as part
5842 -- of the record).
5848 then
5856 then
5861 ------------------
5862 -- Warn_Overlay --
5863 ------------------
5865 procedure Warn_Overlay
5869 is
5871 -- The object to which the address clause applies
5877 begin
5878 -- No warning if address clause overlay warnings are off
5884 -- No warning if there is an explicit initialization
5892 -- We only give the warning for non-imported entities of a type for
5893 -- which a non-null base init proc is defined, or for objects of access
5894 -- types with implicit null initialization, or when Normalize_Scalars
5895 -- applies and the type is scalar or a string type (the latter being
5896 -- tested for because predefined String types are initialized by inline
5897 -- code rather than by an init_proc). Note that we do not give the
5898 -- warning for Initialize_Scalars, since we suppressed initialization
5899 -- in this case. Also, do not warn if Suppress_Initialization is set.
5909 then
5912 then
5917 then
5924 then
5931 -- A function call (most likely to To_Address) is probably not an
5932 -- overlay, so skip warning. Ditto if the function call was inlined
5933 -- and transformed into an entity.
5941 -- If a pragma Import follows, we assume that it is for the current
5942 -- target of the address clause, and skip the warning.
5947 then
5953 Error_Msg_N
5955 Nam);
5956 else
5957 Error_Msg_N
5959 Nam);
5962 -- Add friendly warning if initialization comes from a packed array
5963 -- component.
5966 declare
5969 begin
5974 then
5978 then
5979 Error_Msg_NE
5984 else
5991 Error_Msg_N
5994 Nam);